Sample records for platelet storage lesion

  1. Platelet storage lesion in interim platelet unit concentrates: A comparison with buffy-coat and apheresis concentrates.

    PubMed

    Singh, Sukhi; Shams Hakimi, Caroline; Jeppsson, Anders; Hesse, Camilla

    2017-12-01

    Platelet storage lesion is characterized by morphological changes and impaired platelet function. The collection method and storage medium may influence the magnitude of the storage lesion. The aim of this study was to compare the newly introduced interim platelet unit (IPU) platelet concentrates (PCs) (additive solution SSP+, 40% residual plasma content) with the more established buffy-coat PCs (SSP, 20% residual plasma content) and apheresis PCs (autologous plasma) in terms of platelet storage lesions. Thirty PCs (n=10 for each type) were assessed by measuring metabolic parameters (lactate, glucose, and pH), platelet activation markers, and in vitro platelet aggregability on days 1, 4, and 7 after donation. The expression of platelet activation markers CD62p (P-selectin), CD63 (LAMP-3), and phosphatidylserine was measured using flow cytometry and in vitro aggregability was measured with multiple electrode aggregometry. Higher platelet activation and lower in vitro aggregability was observed in IPU than in buffy-coat PCs on day 1 after donation. In contrast, metabolic parameters, expression of platelet activation markers, and in vitro aggregability were better maintained in IPU than in buffy-coat PCs at the end of the storage period. Compared to apheresis PCs, IPU PCs had higher expression of activation markers and lower in vitro aggregability throughout storage. In conclusion, the results indicate that there are significant differences in platelet storage lesions between IPU, buffy-coat, and apheresis PCs. The quality of IPU PCs appears to be at least comparable to buffy-coat preparations. Further studies are required to distinguish the effect of the preparation methods from storage conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Platelet Storage Lesions: What More Do We Know Now?

    PubMed

    Ng, Monica Suet Ying; Tung, John-Paul; Fraser, John Francis

    2018-04-17

    Platelet concentrate (PC) transfusions are a lifesaving adjunct to control and prevent bleeding in cancer, hematologic, surgical, and trauma patients. Platelet concentrate availability and safety are limited by the development of platelet storage lesions (PSLs) and risk of bacterial contamination. Platelet storage lesions are a series of biochemical, structural, and functional changes that occur from blood collection to transfusion. Understanding of PSLs is key for devising interventions that prolong PC shelf life to improve PC access and wastage. This article will review advancements in clinical and mechanistic PSL research. In brief, exposure to artificial surfaces and high centrifugation forces during PC preparation initiate PSLs by causing platelet activation, fragmentation, and biochemical release. During room temperature storage, enhanced glycolysis and reduced mitochondrial function lead to glucose depletion, lactate accumulation, and product acidification. Impaired adenosine triphosphate generation reduces platelet capacity to perform energetically demanding processes such as hypotonic stress responses and activation/aggregation. Storage-induced alterations in platelet surface proteins such as thrombin receptors and glycoproteins decrease platelet aggregation. During storage, there is an accumulation of immunoactive proteins such as leukocyte-derive cytokines (tumor necrosis factor α, interleukin (IL) 1α, IL-6, IL-8) and soluble CD40 ligand which can participate in transfusion-related acute lung injury and nonhemolytic transfusion reactions. Storage-induced microparticles have been linked to enhanced platelet aggregation and immune system modulation. Clinically, stored PCs have been correlated with reduced corrected count increment, posttransfusion platelet recovery, and survival across multiple meta-analyses. Fresh PC transfusions have been associated with superior platelet function in vivo; however, these differences were abrogated after a period of

  3. Responsiveness of platelets during storage studied with flow cytometry--formation of platelet subpopulations and LAMP-1 as new markers for the platelet storage lesion.

    PubMed

    Södergren, A L; Tynngård, N; Berlin, G; Ramström, S

    2016-02-01

    Storage lesions may prevent transfused platelets to respond to agonists and arrest bleeding. The aim of this study was to evaluate and quantify the capacity of platelet activation during storage using flow cytometry and new markers of platelet activation. Activation responses of platelets prepared by apheresis were measured on days 1, 5, 7 and 12. In addition, comparisons were made for platelet concentrates stored until swirling was affected. Lysosome-associated membrane protein-1 (LAMP-1), P-selectin and phosphatidylserine (PS) exposure were assessed by flow cytometry on platelets in different subpopulations in resting state or following stimulation with platelet agonists (cross-linked collagen-related peptide (CRP-XL), PAR1- and PAR4-activating peptides). The ability to form subpopulations upon activation was significantly decreased already at day 5 for some agonist combinations. The agonist-induced exposure of PS and LAMP-1 also gradually decreased with time. Spontaneous exposure of P-selectin and PS increased with time, while spontaneous LAMP-1 exposure was unchanged. In addition, agonist-induced LAMP-1 expression clearly discriminated platelet concentrates with reduced swirling from those with retained swirling. This suggests that LAMP-1 could be a good marker to capture changes in activation capacity in stored platelets. The platelet activation potential seen as LAMP-1 exposure and fragmentation into platelet subpopulations is potential sensitive markers for the platelet storage lesion. © 2015 International Society of Blood Transfusion.

  4. Overview on platelet preservation: better controls over storage lesion.

    PubMed

    Ohto, Hitoshi; Nollet, Kenneth E

    2011-06-01

    Platelet storage lesion (PSL), correlating with reduced in vivo recovery/survival and hemostatic capacity after transfusion, is characterized essentially by morphological and molecular evidence of platelet activation and energy consumption in the medium. Processes that limit shelf-life are multifactorial, and include both necrosis and apoptosis. PSL is greatly influenced by factors including duration of storage, temperature, ratio of platelet number to media volume, solution composition with respect to energy content and buffering capacity, and gas permeability of the container. Recent progress for slowing PSL has been made with storage media that more effectively fuel ATP production and buffer the inevitable effects of metabolism. Improved oxygen-permeability of containers also helps to maintain aerobic-dominant glycolysis. Patients stand to benefit from platelet products of higher intrinsic quality that store well until the moment of transfusion. Copyright © 2011. Published by Elsevier Ltd.

  5. A signaling pathway contributing to platelet storage lesion development: targeting PI3-kinase–dependent Rap1 activation slows storage-induced platelet deterioration

    PubMed Central

    Schubert, Peter; Thon, Jonathan N.; Walsh, Geraldine M.; Chen, Cindy H.I.; Moore, Edwin D.; Devine, Dana V.; Kast, Juergen

    2015-01-01

    BACKGROUND The term platelet storage lesion (PSL) describes the structural and biochemical changes in platelets (PLTs) during storage. These are typified by alterations of morphologic features and PLT metabolism leading to reduced functionality and hence reduced viability for transfusion. While the manifestations of the storage lesion are well characterized, the biochemical pathways involved in the initiation of this process are unknown. STUDY DESIGN AND METHODS A complementary proteomic approach has recently been applied to analyze changes in the PLT proteome during storage. By employing stringent proteomic criteria, 12 proteins were identified as significantly and consistently changing in relative concentration over a 7-day storage period. Microscopy, Western blot analysis, flow cytometry, and PLT functionality analyses were used to unravel the involvement of a subset of these 12 proteins, which are connected through integrin signaling in one potential signaling pathway underlying storage lesion development. RESULTS Microscopic analysis revealed changes in localization of glycoprotein IIIa, Rap1, and talin during storage. Rap1 activation was observed to correlate with expression of the PLT activation marker CD62P. PLTs incubated for 7 days with the PI3-kinase inhibitor LY294002 showed diminished Rap1 activation as well as a moderate reduction in integrin αIIbβ3 activation and release of α-granules. Furthermore, this inhibitor seemed to improve PLT integrity and quality during storage as several in vitro probes showed a deceleration of PLT activation. CONCLUSION These results provide the first evidence for a signaling pathway mediating PSL in which PI3-kinase–dependent Rap1 activation leads to integrin αIIbβ3 activation and PLT degranulation. PMID:19497060

  6. The role of microRNAs in platelet biology during storage.

    PubMed

    Yan, Yuzhong; Zhang, Jingjun; Zhang, Qi; Chen, Yanping; Zhu, Xinfang; Xia, Rong

    2017-04-01

    Platelet storage lesions seriously affect the quality of stored platelets, even causing them to be ineffective in vivo after transfusion. Past research have been focused on what mechanism(s) cause the formation of storage lesions. One proposed mechanism is microRNAs (miRNAs)-based molecular regulation of the platelet mRNAs that are relevant to the storage lesion. Platelets continue to translate proteins from mRNA while in a storage environment. A strong correlation exists between the platelet transcriptome and its subsequent proteomic profile, which supports de novo platelet translational capabilities. Thus, miRNA may play a crucial role in platelet biology during storage conditions. Importantly, this suggests the exciting possibility of post-transcriptional regulation of gene expression in platelets that are in storage. Given this, the differential profiling of miRNAs could be a useful tool in identifying changes to ex vivo stored platelets. Any identified miRNAs could then be considered as potential markers to assess the viability of platelet concentrates. The present review summarizes the current experimental and clinical evidence that clarifies the role miRNAs play during platelet ex vivo storage. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Platelet concentrates for transfusion-metabolic and storage aspects.

    PubMed

    Farrugia, A

    1994-01-01

    Transfusion of platelets concentrated from donated blood is an established therapeutic modality in clinical medicine. Over the past 25 years much effort has gone into optimising the conditions for the collection, preparation and storage of platelets for transfusion. Despite significant advances, platelet production is still a costly process requiring a dedicated environment and the use of specially formulated plastic storage containers. A progressive lesion over storage limits the shelf life and the availability of donated platelets, while the need to store platelets in the donor's autologous plasma also results in a loss of valuable fresh plasma for fractionation. Recent studies have addressed the issues of platelet quality and plasma economy by examining the possibility of storing platelets in a synthetic medium. Platelets stored in a variety of crystalloid solutions have been shown to retain in vitro and in vivo properties equivalent or superior to platelets stored in autologous donor plasma. Some additional insight has been gained on the metabolic patterns of stored platelets. In particular, studies have shown that, under these conditions, platelets are unable to oxidise dextrose to any significant extent, and that dextrose is invariably broken down to lactate, irrespective of the oxygen tensions in the platelet's environment. This in turn leads to the metabolic lesion of platelet storage, whereby low pH results in loss of platelet viability. Platelets stored in synthetic dextrose-free media are capable of maintaining aerobic ATP generation, and acetate-a component of many media studied-has been shown to be metabolised by platelets. Similarly, platelets prepared from blood collected into a dextrose-free anticoagulant have satisfactory properties both when suspended in autologous plasma or in a dextrose-free synthetic medium. The requirements for storage in special, high gas-permeable, containers, and for constant agitation during storage, were both found to be

  8. Storage of platelets: effects associated with high platelet content in platelet storage containers.

    PubMed

    Gulliksson, Hans; Sandgren, Per; Sjödin, Agneta; Hultenby, Kjell

    2012-04-01

    A major problem associated with platelet storage containers is that some platelet units show a dramatic fall in pH, especially above certain platelet contents. The aim of this study was a detailed investigation of the different in vitro effects occurring when the maximum storage capacity of a platelet container is exceeded as compared to normal storage. Buffy coats were combined in large-volume containers to create primary pools to be split into two equal aliquots for the preparation of platelets (450-520×10(9) platelets/unit) in SSP+ for 7-day storage in two containers (test and reference) with different platelet storage capacity (n=8). Exceeding the maximum storage capacity of the test platelet storage container resulted in immediate negative effects on platelet metabolism and energy supply, but also delayed effects on platelet function, activation and disintegration. Our study gives a very clear indication of the effects in different phases associated with exceeding the maximum storage capacity of platelet containers but throw little additional light on the mechanism initiating those negative effects. The problem appears to be complex and further studies in different media using different storage containers will be needed to understand the mechanisms involved.

  9. Early storage lesions in apheresis platelets are induced by the activation of the integrin αIIbβ₃ and focal adhesion signaling pathways.

    PubMed

    Thiele, Thomas; Iuga, Cristina; Janetzky, Susann; Schwertz, Hansjorg; Gesell Salazar, Manuela; Fürll, Birgit; Völker, Uwe; Greinacher, Andreas; Steil, Leif

    2012-12-05

    Production and storage of platelet concentrates (PC) induce protein changes in platelets leading to impaired platelet function. This study aimed to identify signaling pathways involved in the development of early platelet storage lesions in apheresis-PCs stored in plasma or additive solution (PAS). Apheresis-PCs from four donors were stored in plasma or in PAS at 22°C (n=4 each). Platelets were analyzed at day 0 (production day) and after 1, 6 and 9 days of storage. Platelet response to agonists (TRAP, collagen, ADP) and to hypotonic shock decreased, CD62P expression increased in both storage media over time. Using DIGE 1550 protein spots were monitored and compared to baseline values at day 0. Platelets in plasma displayed changes in 352 spots (166/day 1, 263/day 6 and 201/day 9); in PAS 325 spots changed (202/day 1, 221/day 6, 200/day 9). LC-ESI-MS/MS analysis of 405 platelet proteins revealed 32 proteins changed during storage in plasma (9/day 1, 15/day 6 and 26/day 9) and 28 in PAS (5/day 1, 20/day 6, 26/day 9). Ingenuity pathway analysis found integrin-αII(b)β(3) and focal adhesion signaling pathways involved in early alterations, being confirmed by Western blotting. Corresponding mRNAs in platelets were identified by next generation sequencing for 84 changed proteins. Integrin-αII(b)β(3) and focal adhesion signaling cause irreversible early storage lesions in apheresis platelets. This article is part of a Special Issue entitled: Integrated omics. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Impact of glucose and acetate on the characteristics of the platelet storage lesion in platelets suspended in additive solutions with minimal plasma.

    PubMed

    Saunders, C; Rowe, G; Wilkins, K; Collins, P

    2013-07-01

    Glucose and acetate have been proposed to be required elements in platelet storage media. This study investigated the role of these compounds on the varied elements that comprise the platelet storage lesion. For each replicate, four pooled and split ABO group-specific buffy coat-derived platelet concentrates were suspended in an in-house additive solution with minimal plasma and varying final concentrations of acetate or glucose. Units were sampled on days 2, 3, 6, 8 and 10 and tested for markers of platelet morphology, activation, function, metabolism and indicators of cell death. The absence of glucose was associated with a decrease in ATP, falling to a mean of 1·1 ± 0·1 μmol/10(11) plts in units with no added glucose compared with 4·2 ± 0·6 μmol/10(11) plts (P < 0·001) in units with 30 mm glucose. As glucose became depleted, the decrease in ATP to levels below 3 μmol/10(11) plts was associated with an increase in both annexin V binding and intracellular free calcium. In units lacking exogenous acetate, ATP levels on day 10 were 5·2 ± 1·5 μmol/10(11) plts compared with 2·7 ± 0·9 μmol/10(11) plts in units with 56 mm acetate (P = 0·006). Higher concentrations of exogenous acetate were associated with a lower hypotonic shock response and higher surface expression of CD62P suggestive of a dose dependency. Under current physical storage conditions, glucose appears necessary for the maintenance of platelets stored as concentrates in minimal volumes of plasma. The addition of acetate was associated with increased platelet activation and reduced ATP levels. © 2013 International Society of Blood Transfusion.

  11. Refrigeration, cryopreservation and pathogen inactivation: an updated perspective on platelet storage conditions.

    PubMed

    Waters, L; Cameron, M; Padula, M P; Marks, D C; Johnson, L

    2018-05-01

    Conventional storage of platelet concentrates limits their shelf life to between 5 and 7 days due to the risk of bacterial proliferation and the development of the platelet storage lesion. Cold storage and cryopreservation of platelets may facilitate extension of the shelf life to weeks and years, and may also provide the benefit of being more haemostatically effective than conventionally stored platelets. Further, treatment of platelet concentrates with pathogen inactivation systems reduces bacterial contamination and provides a safeguard against the risk of emerging and re-emerging pathogens. While each of these alternative storage techniques is gaining traction individually, little work has been done to examine the effect of combining treatments in an effort to further improve product safety and minimize wastage. This review aims to discuss the benefits of alternative storage techniques and how they may be combined to alleviate the problems associated with conventional platelet storage. © 2018 International Society of Blood Transfusion.

  12. Biochemistry of storage lesions of red cell and platelet concentrates: A continuous fight implying oxidative/nitrosative/phosphorylative stress and signaling.

    PubMed

    Rinalducci, Sara; Zolla, Lello

    2015-06-01

    The mechanisms responsible for the reduced lifespan of transfused red blood cells (RBCs) and platelets (PLTs) are still under investigation, however one explanation refers to the detrimental biochemical changes occurring during ex vivo storage of these blood products. A myriad of historical and more recent studies has contributed to advance our understanding of storage lesion. Without any doubts, proteomics had great impact on transfusion medicine by profiling the storage-dependent changes in the total detectable protein pool of both RBCs and PLTs. This review article focuses on the role of oxidative/nitrosative stress in developing RBC and PLT storage lesions, with a special glance at its biochemistry and cross-talk with phosphorylative signal transduction. In this sense, we enlighten the potential contribution of new branches of proteomics in identifying novel points of intervention for the improvement of blood product quality. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. The combined effect of platelet storage media and intercept pathogen reduction technology on platelet activation/activability and cellular apoptosis/necrosis: Lisbon-RBS experience.

    PubMed

    Carvalho, Helena; Alguero, Carmen; Santos, Matilde; de Sousa, Gracinda; Trindade, Helder; Seghatchian, Jerard

    2006-04-01

    Platelets are known to undergo shape change, activation, a release reaction and apoptosis/necrosis during processing and storage, all of which are collectively known as the platelet storage lesion. Any additional processing may have some deleterious impact on platelet activability and functional integrity, which need to be investigated. This preliminary investigation was undertaken to establish the combined effects of standard platelet storage media and the intercept pathogen reduction technology on platelet activation and activability during 7 day storage, using buffy-coat derived platelets in standard storage media containing 35% plasma (N=24). P-selectin (CD62p) expression, a classical marker of platelet activation, and phosphatidylserine (PS) exposure on the platelet surface membrane, a hallmark of cellular necrosis/apoptosis, were both measured by flow cytometry. The results reveal significant increases in activation, from an average of 22.7% on day 1 before treatment to 31.6% on day 2 after treatment and 58.7% at the end of storage. Concomitantly, the basal expression of PS was slightly increased from 1.9% to 2.8% at day 2 after treatment and 7.3% at the end of storage. However, the functional reserve of platelets during storage, which reflects their capability to undergo activation and the release reaction when platelets were challenged with either calcium ionophore or thrombin, was relatively well maintained. These preliminary data confirm the earlier data on the use of intercept, and for the first time, based on the assessment of platelet functional integrity, suggest that platelet functional reserve is relatively well maintained, with little change in the formation of apoptotic cells.

  14. A comprehensive proteomics study on platelet concentrates: Platelet proteome, storage time and Mirasol pathogen reduction technology.

    PubMed

    Salunkhe, Vishal; De Cuyper, Iris M; Papadopoulos, Petros; van der Meer, Pieter F; Daal, Brunette B; Villa-Fajardo, María; de Korte, Dirk; van den Berg, Timo K; Gutiérrez, Laura

    2018-03-19

    Platelet concentrates (PCs) represent a blood transfusion product with a major concern for safety as their storage temperature (20-24°C) allows bacterial growth, and their maximum storage time period (less than a week) precludes complete microbiological testing. Pathogen inactivation technologies (PITs) provide an additional layer of safety to the blood transfusion products from known and unknown pathogens such as bacteria, viruses, and parasites. In this context, PITs, such as Mirasol Pathogen Reduction Technology (PRT), have been developed and are implemented in many countries. However, several studies have shown in vitro that Mirasol PRT induces a certain level of platelet shape change, hyperactivation, basal degranulation, and increased oxidative damage during storage. It has been suggested that Mirasol PRT might accelerate what has been described as the platelet storage lesion (PSL), but supportive molecular signatures have not been obtained. We aimed at dissecting the influence of both variables, that is, Mirasol PRT and storage time, at the proteome level. We present comprehensive proteomics data analysis of Control PCs and PCs treated with Mirasol PRT at storage days 1, 2, 6, and 8. Our workflow was set to perform proteomics analysis using a gel-free and label-free quantification (LFQ) approach. Semi-quantification was based on LFQ signal intensities of identified proteins using MaxQuant/Perseus software platform. Data are available via ProteomeXchange with identifier PXD008119. We identified marginal differences between Mirasol PRT and Control PCs during storage. However, those significant changes at the proteome level were specifically related to the functional aspects previously described to affect platelets upon Mirasol PRT. In addition, the effect of Mirasol PRT on the platelet proteome appeared not to be exclusively due to an accelerated or enhanced PSL. In summary, semi-quantitative proteomics allows to discern between proteome changes due to

  15. Maximising platelet availability by delaying cold storage.

    PubMed

    Wood, B; Johnson, L; Hyland, R A; Marks, D C

    2018-04-06

    Cold-stored platelets may be an alternative to conventional room temperature (RT) storage. However, cold-stored platelets are cleared more rapidly from circulation, reducing their suitability for prophylactic transfusion. To minimise wastage, it may be beneficial to store platelets conventionally until near expiry (4 days) for prophylactic use, transferring them to refrigerated storage to facilitate an extended shelf life, reserving the platelets for the treatment of acute bleeding. Two ABO-matched buffy-coat-derived platelets (30% plasma/70% SSP+) were pooled and split to produce matched pairs (n = 8 pairs). One unit was stored at 2-6°C without agitation (day 1 postcollection; cold); the second unit was stored at 20-24°C with constant agitation until day 4 then stored at 2-6°C thereafter (delayed-cold). All units were tested for in vitro quality periodically over 21 days. During storage, cold and delayed-cold platelets maintained a similar platelet count. While pH and HSR were significantly higher in delayed-cold platelets, other metabolic markers, including lactate production and glucose consumption, did not differ significantly. Furthermore, surface expression of phosphatidylserine and CD62P, release of soluble CD62P and microparticles were not significantly different, suggesting similar activation profiles. Aggregation responses of delayed-cold platelets followed the same trend as cold platelets once transferred to cold storage, gradually declining over the storage period. The metabolic and activation profile of delayed-cold platelets was similar to cold-stored platelets. These data suggest that transferring platelets to refrigerated storage when near expiry may be a viable option for maximising platelet inventories. © 2018 International Society of Blood Transfusion.

  16. Exploratory studies of extended storage of apheresis platelets in a platelet additive solution (PAS)

    PubMed Central

    Corson, Jill; Jones, Mary Kay; Christoffel, Todd; Pellham, Esther; Bailey, S. Lawrence; Bolgiano, Doug

    2014-01-01

    To evaluate the poststorage viability of apheresis platelets stored for up to 18 days in 80% platelet additive solution (PAS)/20% plasma, 117 healthy subjects donated platelets using the Haemonetics MCS+, COBE Spectra (Spectra), or Trima Accel (Trima) systems. Control platelets from the same subjects were compared with their stored test PAS platelets by radiolabeling their stored and control platelets with either 51chromium or 111indium. Trima platelets met Food and Drug Administration poststorage platelet viability criteria for only 7 days vs almost 13 days for Haemonetics platelets; ie, platelet recoveries after these storage times averaged 44 ± 3% vs 49 ± 3% and survivals were 5.4 ± 0.3 vs 4.6 ± 0.3 days, respectively. The differences in storage duration are likely related to both the collection system and the storage bag. The Spectra and Trima platelets were hyperconcentrated during collection, and PAS was added, whereas the Haemonetics platelets were elutriated with PAS, which may have resulted in less collection injury. When Spectra and Trima platelets were stored in Haemonetics’ bags, poststorage viability was significantly improved. Platelet viability is better maintained in vitro than in vivo, allowing substantial increases in platelet storage times. However, implementation will require resolution of potential bacterial overgrowth during storage. PMID:24258816

  17. EXTENDED STORAGE OF BUFFY-COAT PLATELET CONCENTRATES IN PLASMA OR A PLATELET ADDITIVE SOLUTION

    PubMed Central

    Slichter, Sherrill J.; Bolgiano, Doug; Corson, Jill; Jones, Mary Kay; Christoffel, Todd; Bailey, S. Lawrence; Pellham, Esther

    2014-01-01

    Background Platelet concentrates prepared from whole blood in the U.S. are made using the platelet-rich-plasma (PRP) method. The platelet concentrates must be made within 8 hours of blood collection and stored for only 5 days. In Europe and Canada, platelet concentrates are made using the buffy-coat (BC) method from whole blood held overnight at 22°C and storage times may be up to 7 days. Our studies were designed to determine how long BC platelets can be stored in plasma or Plasmalyte while meeting the FDA’s post-storage viability criteria. Study Design, Materials, And Methods Normal subjects donated whole blood that was stored at 22°C for 22 ± 2 hours prior to preparation of BC platelets. Platelets were stored for 5 to 8 days in either plasma or Plasmalyte concentrations of 65% or 80%. Radiolabeled autologous stored versus fresh platelet recoveries and survivals were assessed as well as post-storage in vitro assays. Results BC platelets stored in either plasma or 65% Plasmalyte met FDA post-storage platelet recovery criteria for 7 days but survivals for only 6 days, while storage in 80% Plasmalyte gave very poor results. Both stored platelet recoveries and survivals correlated with the same donor’s fresh results, but the correlation was much stronger between recoveries than survivals. In vitro measures of extent of shape change, morphology score, and pH best predicted post-storage platelet recoveries, while annexin V binding best predicted platelet survivals. Conclusion BC platelets stored in either plasma or 65% Plasmalyte meet FDA’s post-storage viability criteria for 6 days. PMID:24673482

  18. Scott Murphy, MD: platelet storage pioneer.

    PubMed

    Vassallo, Ralph

    2011-04-01

    Dr Scott Murphy was a leading authority in the science of platelet storage for transfusion. Among the first to advocate room-temperature storage, his work enabled the extension of platelet shelf life, which facilitated the development of aggressive medical and surgical therapies requiring intensive platelet support. During a 38-year career, he characterized the metabolism of stored platelets, worked to optimize storage conditions, and developed a landmark standard for the assessment of platelet quality. As a clinical hematologist, he was devoted to his patients, providing compassionate, comforting care. He was also a cherished mentor, a sage advisor, a fast friend, and a dedicated family man. Dr Murphy was one of those rare, great, humble men who inspire and enrich everyone around him. Truly one of transfusion medicine's leaders, Scott is remembered by those whose lives he touched for his warmth, wit, and wisdom. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Intraplatelet reactive oxygen species (ROS) correlate with the shedding of adhesive receptors, microvesiculation and platelet adhesion to collagen during storage: Does endogenous ROS generation downregulate platelet adhesive function?

    PubMed

    Ghasemzadeh, Mehran; Hosseini, Ehteramolsadat; Roudsari, Zahra Oushyani; Zadkhak, Parvin

    2018-03-01

    Platelets storage lesion is mainly orchestrated by platelet activating signals during storage. Reactive oxygen species (ROS) are being considered as important signaling molecules modulating platelet function while their production has also been shown to be augmented by platelet activation. This study investigated to what extent endogenous ROS generation during platelet storage could be correlated with platelet receptor shedding, microvesiculation and adhesive function. 10 PRP-platelet concentrates were subjected to flow cytometry analysis to examine the generation of intraplatelet ROS on days 1, 5 and 7 after storage. In 5 day-stored platelets considering 40% of ROS generation as a cutoff point, samples were divided into two groups of those with higher or lower levels of ROS. The expression of adhesion receptors (GPVI, GPIbα), the amount of microparticles and phosphatidylserine exposure in each group were then examined by flow cytometry. Platelet receptor shedding and adhesion to collagen matrix were respectively measured by western blotting and microscopic assays. Our data showed lowered expression of GPIbα (p < 0.05) and GPVI in samples with ROS > 40% than those with ROS ≤ 40%, whereas receptors shedding and microvesiculation were (p < 0.05) elevated in platelets with higher levels of ROS. Functionally, we observed significantly (p < 0.05) lower levels of platelet adhesion to collagen matrix in samples with ROS generation more than 40%. Taken together, we showed correlations between intraplatelet ROS generation and either platelet receptors or microparticle shedding as well as platelet adhesive capacity to collagen. These findings suggest that augmented ROS generation during storage might be relevant to down-regulation of platelet adhesive function. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Amelioration of lesions associated with 24-hour suboptimal platelet storage at 16 °C by a p38MAPK inhibitor, VX-702.

    PubMed

    Wagner, S J; Skripchenko, A; Seetharaman, S; Kurtz, J

    2015-04-01

    Previous studies with p38MAPK inhibitors at room temperature demonstrated that they improve a large number of platelet storage parameters, but cannot substantially inhibit p38MAPK activation nor protect against widespread decrements in platelet quality parameters during 4 °C storage. In this study, platelet quality parameters and inhibition of p38MAPK by VX-702 were studied after incubation of platelets at 16 °C without agitation, suboptimal storage conditions which produce moderate platelet decrements. Trima apheresis units were collected and aliquoted into three 60-ml CLX storage bags: (i) a control aliquot which was held at 20-24 °C with constant agitation; (ii) a test aliquot which was held at 20-24 °C with agitation until Day 2, when it was reincubated at 16 ± 1 °C for 24 ± 0·5 h without agitation and then returned 20-24 °C with agitation; (iii) a test aliquot containing 1 μm VX-702 stored in an identical fashion as aliquot 2. Aliquots were tested for an array of platelet storage parameters and p38MAPK activation on Days 1, 4 and 7. Many platelet storage parameters and p38MAPK activation were adversely affected by 24-h incubation at 16 °C without agitation. With the exception of ESC, addition of VX-702 prevented p38MAPK activation and the decrements in most observed parameters. Unlike 4 °C storage, VX-702 prevents activation of p38MAPK and decrements in many platelet storage parameters after exposure to 16 °C without agitation for 24 h. © 2014 International Society of Blood Transfusion.

  1. In vitro storage characteristics of platelet concentrates suspended in 70% SSP+(TM) additive solution versus plasma over a 14-day storage period.

    PubMed

    Saunders, C; Rowe, G; Wilkins, K; Holme, S; Collins, P

    2011-08-01

    The non-paired two-arm study compared the in vitro storage characteristics of platelets suspended as concentrates in either 100% plasma or a mixture of additive solution (SSP+™, MacoPharma, Mouveaux, France) and autologous plasma in a 70:30 ratio over a 14-day storage period. The buffy coat-derived pooled platelet concentrates were sampled on days 1, 2, 3, 6, 8, 10 and 14 and tests performed to determine platelet morphology, function, metabolism, activation and apoptosis-like activity. Swirling remained strong (score=3) in SSP+™, whilst scores of 1 and 0 were noted for plasma units by end of storage. In contrast to units in plasma, pH levels remained above seven in SSP+™ units, increasing after day 10. Percent positive expression of CD62P was similar in both groups on day 1 (median of 54% and 56% for plasma (n=13) and SSP+™ (n=12), respectively), with SSP+™ units showing a more moderate increase in activation after day 10. A progressive decrease in mitochondrial membrane potential was evident in both groups from day 1, whilst annexin V binding was relatively stable from days 1 to 3, with median values remaining below 6%. Subsequent to this, the percentage of platelets binding annexin V increased to approximately 30% by day 14. Platelets suspended in a medium of 70:30 SSP+™ to plasma ratio performed at least as well as platelets in 100% autologous plasma for up to 10 days of storage. Further, results are suggestive of an apoptosis-like process being involved in the platelet storage lesion. © 2011 The Author(s). Vox Sanguinis © 2011 International Society of Blood Transfusion.

  2. Glucose ameliorates the metabolic profile and mitochondrial function of platelet concentrates during storage in autologous plasma

    PubMed Central

    Amorini, Angela M.; Tuttobene, Michele; Tomasello, Flora M.; Biazzo, Filomena; Gullotta, Stefano; De Pinto, Vito; Lazzarino, Giuseppe; Tavazzi, Barbara

    2013-01-01

    Background It is essential that the quality of platelet metabolism and function remains high during storage in order to ensure the clinical effectiveness of a platelet transfusion. New storage conditions and additives are constantly evaluated in order to achieve this. Using glucose as a substrate is controversial because of its potential connection with increased lactate production and decreased pH, both parameters triggering the platelet lesion during storage. Materials and methods In this study, we analysed the morphological status and metabolic profile of platelets stored for various periods in autologous plasma enriched with increasing glucose concentrations (13.75, 27.5 and 55 mM). After 0, 2, 4, 6 and 8 days, high energy phosphates (ATP, GTP, ADP, AMP), oxypurines (hypoxanthine, xanthine, uric acid), lactate, pH, mitochondrial function, cell lysis and morphology, were evaluated. Results The data showed a significant dose-dependent improvement of the different parameters in platelets stored with increasing glucose, compared to what detected in controls. Interestingly, this phenomenon was more marked at the highest level of glucose tested and in the period of time generally used for platelet transfusion (0–6 days). Conclusion These results indicate that the addition of glucose during platelet storage ameliorates, in a dose-dependent manner, the biochemical parameters related to energy metabolism and mitochondrial function. Since there was no correspondence between glucose addition, lactate increase and pH decrease in our experiments, it is conceivable that platelet derangement during storage is not directly caused by glucose through an increase of anaerobic glycolysis, but rather to a loss of mitochondrial functions caused by reduced substrate availability. PMID:22682337

  3. Platelet granule release is associated with reactive oxygen species generation during platelet storage: A direct link between platelet pro-inflammatory and oxidation states.

    PubMed

    Ghasemzadeh, Mehran; Hosseini, Ehteramolsadat

    2017-08-01

    Upon platelet stimulation with agonists, reactive oxygen species (ROS) generation enhances platelet activation and granule release. Whether ROS generation during platelet storage could be directly correlated with the expression of proinflammatory molecules and granule release has been investigated in this study. PRP-platelet concentrates were subjected to flowcytometry analysis to assess the expression of platelet activation marker, P-selectin and CD40L during storage. Intracellular ROS generation was also detected in platelet by flowcytometry using dihydrorhodamine (DHR) 123. Through the dual staining, ROS production was analyzed in either P-selectin positive or negative populations. ROS formation in platelet population was significantly increased by either TRAP (a potent agonist that induces granule release) or PMA (a classic inducer of ROS generation), while the effects of each agonists on P-selectin expression and ROS generation in platelets were comparable. Platelet storage was also associated with the increasing levels of ROS (day 0 vs. day 5; p<0.001) while this increasing pattern was directly correlated with the either expressed P-selectin or CD40L. In addition, in 5 day-stored platelets, samples with ROS levels above 40% showed significantly higher levels of P-selectin and CD40L expression. P-selectin negative population of platelet did not show significant amount of ROS. Our data demonstrated decreased levels of important platelet pro-inflammatory molecules in stored platelets with lower levels of intraplatelet ROS. However, whether quenching of ROS generation during platelet storage can attenuate adverse transfusion reactions raised by platelet pro-inflammatory status is required to be further studied. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. A critical role of platelet adhesion in the initiation of atherosclerotic lesion formation.

    PubMed

    Massberg, Steffen; Brand, Korbinian; Grüner, Sabine; Page, Sharon; Müller, Elke; Müller, Iris; Bergmeier, Wolfgang; Richter, Thomas; Lorenz, Michael; Konrad, Ildiko; Nieswandt, Bernhard; Gawaz, Meinrad

    2002-10-07

    The contribution of platelets to the process of atherosclerosis remains unclear. Here, we show in vivo that platelets adhere to the vascular endothelium of the carotid artery in ApoE(-)(/)(-) mice before the development of manifest atherosclerotic lesions. Platelet-endothelial cell interaction involved both platelet glycoprotein (GP)Ibalpha and GPIIb-IIIa. Platelet adhesion to the endothelium coincides with inflammatory gene expression and preceded atherosclerotic plaque invasion by leukocytes. Prolonged blockade of platelet adhesion in ApoE(-)(/)(-) mice profoundly reduced leukocyte accumulation in the arterial intima and attenuated atherosclerotic lesion formation in the carotid artery bifurcation, the aortic sinus, and the coronary arteries. These findings establish the platelet as a major player in initiation of the atherogenetic process.

  5. Studies of Platelet 5-Hydroxytryptamine (Serotonin) in Storage Pool Disease and Albinism

    PubMed Central

    Weiss, Harvey J.; Tschopp, Thomas B.; Rogers, John; Brand, Harvey

    1974-01-01

    Platelets in patients with storage pool disease are markedly deficient in a nonmetabolic (storage) pool of ADP that is important in platelet aggregation. They are also deficient in ATP, although to a lesser degree. In seven patients with this disorder, including one with albinism, platelet 5-hydroxytryptamine (5-HT) levels were reduced in proportion to the reduction in ATP (r = 0.94). Their platelets show diminished capacity to absorb [14C]5-HT, and the type of defect was similar to that produced in normal platelets by reserpine, a drug known to inhibit the uptake of 5-HT by the platelet dense granules. Storage pool-deficient platelets also converted more [3H]5-HT to [3H]5-hydroxyindoleacetic acid than did normal platelets, and the platelets in one of two patients studied contained increased amounts of 5-HT metabolites. The above findings, together with those reported previously, support the conclusion that the capacity of the dense granules (which may be either diminished or functionally abnormal) for storing 5-HT is decreased in storage pool disease; as a result, the 5-HT that enters the platelet may be more exposed to monoamine oxidases present on mitochondrial membranes. This diminished storage capacity (for 5-HT) may also explain why preincubating platelet-rich plasma with 5-HT for 45 min without stirring inhibits subsequent platelet aggregation by 5-HT to a greater degree in patients with storage pool disease than in normal subjects. The latter finding is also consistent with the theory that the aggregation of platelets by 5-HT is mediated by the same receptors on the plasma membrane that are involved in its uptake. The diminished release of platelet-bound [14C]5-HT by collagen that we found in these patients, as well as findings in previous studies, suggests that the release reaction may also be abnormal in storage pool disease. Images PMID:4847252

  6. 21 CFR 864.9575 - Environmental chamber for storage of platelet concentrate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... to hold platelet-rich plasma within a preselected temperature range. (b) Classification. Class II... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Environmental chamber for storage of platelet... Establishments That Manufacture Blood and Blood Products § 864.9575 Environmental chamber for storage of platelet...

  7. 21 CFR 864.9575 - Environmental chamber for storage of platelet concentrate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... to hold platelet-rich plasma within a preselected temperature range. (b) Classification. Class II... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Environmental chamber for storage of platelet... Establishments That Manufacture Blood and Blood Products § 864.9575 Environmental chamber for storage of platelet...

  8. 21 CFR 864.9575 - Environmental chamber for storage of platelet concentrate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... to hold platelet-rich plasma within a preselected temperature range. (b) Classification. Class II... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Environmental chamber for storage of platelet... Establishments That Manufacture Blood and Blood Products § 864.9575 Environmental chamber for storage of platelet...

  9. 21 CFR 864.9575 - Environmental chamber for storage of platelet concentrate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... to hold platelet-rich plasma within a preselected temperature range. (b) Classification. Class II... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Environmental chamber for storage of platelet... Establishments That Manufacture Blood and Blood Products § 864.9575 Environmental chamber for storage of platelet...

  10. 21 CFR 864.9575 - Environmental chamber for storage of platelet concentrate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... to hold platelet-rich plasma within a preselected temperature range. (b) Classification. Class II... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Environmental chamber for storage of platelet... Establishments That Manufacture Blood and Blood Products § 864.9575 Environmental chamber for storage of platelet...

  11. A Critical Role of Platelet Adhesion in the Initiation of Atherosclerotic Lesion Formation

    PubMed Central

    Massberg, Steffen; Brand, Korbinian; Grüner, Sabine; Page, Sharon; Müller, Elke; Müller, Iris; Bergmeier, Wolfgang; Richter, Thomas; Lorenz, Michael; Konrad, Ildiko; Nieswandt, Bernhard; Gawaz, Meinrad

    2002-01-01

    The contribution of platelets to the process of atherosclerosis remains unclear. Here, we show in vivo that platelets adhere to the vascular endothelium of the carotid artery in ApoE − / − mice before the development of manifest atherosclerotic lesions. Platelet–endothelial cell interaction involved both platelet glycoprotein (GP)Ibα and GPIIb-IIIa. Platelet adhesion to the endothelium coincides with inflammatory gene expression and preceded atherosclerotic plaque invasion by leukocytes. Prolonged blockade of platelet adhesion in ApoE − / − mice profoundly reduced leukocyte accumulation in the arterial intima and attenuated atherosclerotic lesion formation in the carotid artery bifurcation, the aortic sinus, and the coronary arteries. These findings establish the platelet as a major player in initiation of the atherogenetic process. PMID:12370251

  12. The Non-Hemostatic Aspects of Transfused Platelets

    PubMed Central

    Sut, Caroline; Tariket, Sofiane; Aubron, Cécile; Aloui, Chaker; Hamzeh-Cognasse, Hind; Berthelot, Philippe; Laradi, Sandrine; Greinacher, Andreas; Garraud, Olivier; Cognasse, Fabrice

    2018-01-01

    Platelets transfusion is a safe process, but during or after the process, the recipient may experience an adverse reaction and occasionally a serious adverse reaction (SAR). In this review, we focus on the inflammatory potential of platelet components (PCs) and their involvement in SARs. Recent evidence has highlighted a central role for platelets in the host inflammatory and immune responses. Blood platelets are involved in inflammation and various other aspects of innate immunity through the release of a plethora of immunomodulatory cytokines, chemokines, and associated molecules, collectively termed biological response modifiers that behave like ligands for endothelial and leukocyte receptors and for platelets themselves. The involvement of PCs in SARs—particularly on a critically ill patient’s context—could be related, at least in part, to the inflammatory functions of platelets, acquired during storage lesions. Moreover, we focus on causal link between platelet activation and immune-mediated disorders (transfusion-associated immunomodulation, platelets, polyanions, and bacterial defense and alloimmunization). This is linked to the platelets’ propensity to be activated even in the absence of deliberate stimuli and to the occurrence of time-dependent storage lesions. PMID:29536007

  13. Hexamoll DINCH plasticised PVC containers for the storage of platelets

    PubMed Central

    Nair, C. S. Bhaskaran; Vidya, R.; Ashalatha, P. M.

    2011-01-01

    Introduction: Containers for the storage of platelets are made using polyvinyl chloride plasticised with di, (2-ethyl hexyl) phthalate, n-butyryl, tri (n-hexyl) citrate and tri (2-ethyl hexyl) mellitate or using special poly olefins without plasticiser. Of these, the first two have disadvantages such as plasticiser leaching and impairment of platelet function. Polyolefin bags cannot be HF welded or steam sterilized. Mellitate plasticised bags can store platelets well for five days but they are not completely phthalate free. Research and Development: We have developed a new generation of containers made of PVC plasticised with the non DEHP, non aromatic plasticiser,1,2- Cyclohexanedicarboxylic acid, diisononyl ester (Hexamoll DINCH) which can store platelets without loss of function for at least six days. Observation: The present studies show that DINCH plasticised PVC bags (TPL-167) are well suited for the storage of platelet concentrates for more than five days. Conclusion: The present studies show that the PVC plasticised with the non phthalate, non aromatic, non toxic plasticiser DINCH is a viable alternative to other existing containers for the storage of platelets for more than five days. PMID:21572709

  14. Platelet lysate formulations based on mucoadhesive polymers for the treatment of corneal lesions.

    PubMed

    Sandri, Giuseppina; Bonferoni, Maria Cristina; Rossi, Silvia; Ferrari, Franca; Mori, Michela; Del Fante, Claudia; Perotti, Cesare; Scudeller, Luigia; Caramella, Carla

    2011-02-01

    Growth factors contained in platelet α-granules initiate and modulate tissue repair and are proposed for the treatment of soft and hard-tissue surgical conditions and in the management of non-healing wounds. Platelet lysate is a hemoderivative obtained from platelet-rich plasma and is capable of releasing a pool of growth factors. Many medical and surgical techniques have been proposed for the treatment of corneal lesions; management of these conditions remains problematic and healing with standard protocols is unattainable. The aim of this study was to develop formulations suitable for prolonging the contact of platelet lysate with the damaged cornea for the time necessary to exert a therapeutic effect. Two vehicles, one based on polyacrylic acid and one based on chitosan, were autoclaved and loaded with platelet lysate and the resultant formulations were characterized for rheology, mucoadhesion, vehicle compatibility and stability. The proliferation effect was tested on two cell culture types (rabbit corneal epithelial cells and fibroblasts). An in-vitro wound-healing test was performed on fibroblasts. In both cases the formulations were compared with platelet lysate diluted with saline at the same concentration. Both formulations maintained the rheological and mucoadhesive properties of the vehicles and the proliferative activity of platelet lysate. The chitosan formulation was able to significantly enhance epithelial cell growth even after storage of up to 2 weeks (in-use conditions), while the polyacrylic acid formulation was less efficient, probably due to the characteristics of the cell model used. The in-vitro wound-healing test performed on fibroblasts confirmed the differences between the two vehicles. The effect induced by the platelet lysate and chitosan formulation was faster than that of the polyacrylic acid formulation and complete in-vitro wound repair was achieved within 48 h. © 2010 The Authors. JPP © 2010 Royal Pharmaceutical Society.

  15. Soft tissue regeneration using leukocyte-platelet rich fibrin after exeresis of hyperplastic gingival lesions: two case reports.

    PubMed

    di Lauro, A E; Abbate, D; Dell'Angelo, B; Iannaccone, G A; Scotto, F; Sammartino, G

    2015-11-02

    Leukocyte-platelet rich fibrin belongs to a second generation of platelet concentrates that does not need biochemical blood manipulation. It is used for tissue healing and regeneration in periodontal and oral-maxillofacial surgery. We report two cases of hyperplastic gingival lesions treated by exeresis and application of leukocyte-platelet rich fibrin membranes in order to improve and accelerate tissue healing. Two patients (a 78-year-old Caucasian woman and a 30-year-old Caucasian man) were treated for hyperplastic gingival lesions. They underwent to exeresis of lesions and application of leukocyte-platelet rich fibrin membranes. Tissue healing was clinically evaluated after 1, 3, 7, 14 and 30 postoperative days. No recurrences were observed after 2 years of semi-annual follow up. We obtained rapid and good healing of soft tissues probably due to the elevated content of leukocytes, platelets and growth factors in the leukocyte-platelet rich fibrin. Based on our results we suggest the use of leukocyte-platelet rich fibrin to cover wounds after exeresis of oral neoformations such as hyperplastic gingival lesions.

  16. Proteomics meets blood banking: identification of protein targets for the improvement of platelet quality.

    PubMed

    Schubert, Peter; Devine, Dana V

    2010-01-03

    Proteomics has brought new perspectives to the fields of hematology and transfusion medicine in the last decade. The steady improvement of proteomic technology is propelling novel discoveries of molecular mechanisms by studying protein expression, post-translational modifications and protein interactions. This review article focuses on the application of proteomics to the identification of molecular mechanisms leading to the deterioration of blood platelets during storage - a critical aspect in the provision of platelet transfusion products. Several proteomic approaches have been employed to analyse changes in the platelet protein profile during storage and the obtained data now need to be translated into platelet biochemistry in order to connect the results to platelet function. Targeted biochemical applications then allow the identification of points for intervention in signal transduction pathways. Once validated and placed in a transfusion context, these data will provide further understanding of the underlying molecular mechanisms leading to platelet storage lesion. Future aspects of proteomics in blood banking will aim to make use of protein markers identified for platelet storage lesion development to monitor proteome changes when alterations such as the use of additive solutions or pathogen reduction strategies are put in place in order to improve platelet quality for patients. (c) 2009 Elsevier B.V. All rights reserved.

  17. Microparticle and mitochondrial release during extended storage of different types of platelet concentrates.

    PubMed

    Marcoux, Geneviève; Duchez, Anne-Claire; Rousseau, Matthieu; Lévesque, Tania; Boudreau, Luc H; Thibault, Louis; Boilard, Eric

    2017-05-01

    On activation, platelets release vesicles called microparticles (MPs). MPs are heterogeneous with regard to the presence or absence of mitochondria. We quantified MPs in platelet concentrates (PCs) taking their mitochondrial content into account. Platelet-rich plasma (PRP), buffy coat (BC) and apheresis (AP) PCs were tested through 7 days of storage. A combination of flow cytometry and spanning-tree progression analysis of density-normalized events (SPADE) was used to determine MP and mitochondrial release during storage. All the PC biochemical parameters complied with transfusion standards at all times. Platelet activation markers increased during storage and were higher for PRP than other types of PCs. Concentrations of MPs and extracellular mitochondria interpreted by SPADE algorithm were significantly higher in PRP than other in PCs and were stable throughout storage. The mode of preparation, rather than storage duration, impacts the release of MPs and mitochondria in PCs.

  18. A proteomic approach reveals the variation in human platelet protein composition after storage at different temperatures.

    PubMed

    Wang, Shichun; Jiang, Tianlun; Fan, Yahan; Zhao, Shuming

    2018-03-29

    Cryopreservation can slow down the metabolism and decrease the risk of bacterial contamination. But, chilled platelets (PLTs) show a reduced period in circulation due to the rapid clearance by hepatic cells or spleen macrophages after transfusion. The deleterious changes that PLTs undergo are mainly considered the result of PLT protein variation. However, the basis for proteomic variation of stored PLTs remains poorly understood. Besides count, activation markers (CD62P and Annexin V), and aggregation, we used quantitative mass spectrometry to create the first comprehensive and quantitative human PLT proteome of samples stored at different temperatures (22°C, 10°C and -80°C). We found different conditions caused different platelet storage lesion (PSL). PLT count was decreased no matter at what temperature stored. PLTs viability at low temperature dropped by 21.78% and 11.21%, respectively, as compared 10.26% at room temperature, there were no significant differences between the storage methods. Membrane expression of CD62P gradually increased in all groups especially stored at 22°C up to 40% and 10°C up to 30%. However, exposure of PS on the PLT membrane was below 1% in every group. The PLT proteome showed there were 575 and 454 potential proteins identified by general iTRAQ analysis and phosphorylation iTRAQ a nalysis, respectively, among them, 33 common differentially expressed proteins caused by storage time and 44 caused by storage temperature Especially, membrane-bound proteins (such as FERMT3, STX4, MYL9 and TAGLN2) played key roles in PLT storage lesion. The pathways "Endocytosis", "Fc gamma R-mediated phagocytosis" and "Regulation of actin cytoskeleton" were affected predominantly by storage time. And the pathways "SNARE interactions in vesicular transport" and "Vasopressin-regulated water reabsorption" were affected by cold storage in our study. Proteomic results can help us to understand PLT biochemistry and physiology and thus unravel the mechanisms

  19. Effects of platelet concentrate storage time reduction in patients after blood stem cell transplantation.

    PubMed

    Heuft, H-G; Goudeva, L; Krauter, J; Peest, D; Buchholz, S; Tiede, A

    2013-07-01

    To evaluate the clinical effect of platelet concentrate (PC) transfusions after PC storage time reduction to 4 days. This was a single-centre cohort study comparing two 3-month periods of time, before and after the reduction of PC storage time from 5 to 4 days. Seventy-seven consecutive patients with PC transfusions were enrolled after blood stem cell transplantation. Corrected platelet count increment (CCI) on the morning after transfusion, time to next platelet transfusion, need for red blood cell (RBC) transfusion and clinical bleeding symptoms were compared. Platelet concentrate storage time was reduced between period 1 (storage for up to 5 days, median storage time 78 h, range 11-136 h) and period 2 (storage for up to 4 days, median storage time 53 h, range 11-112 h). Patients were comparable for age, weight, body surface area, underlying disorder, type of transplantation and transfused platelet dose. The CCI increased from a median of 4 (range 0-20) to 8 (0-68) × 10(9) /l per 10(11) platelets/m(2) (P < 0·0001). Time to next PC transfusion increased from 1·1 to 2·0 days (P < 0·0001). Any bleeding symptom was noted in 20 of 36 patients (56%) vs. 9/41 patients (22%, P < 0·01). Nose bleeds, haematuria and bleeding at more than one site were significantly reduced. Frequency of RBC transfusion within 5 days after PC transfusion was reduced from 74 to 58% (P < 0·0001). Platelet concentrate storage time shortening was associated with highly significant CCI increase, reduced RC needs and lower patient numbers with bleeding events. © 2013 International Society of Blood Transfusion.

  20. Proteome changes in platelets after pathogen inactivation--an interlaboratory consensus.

    PubMed

    Prudent, Michel; D'Alessandro, Angelo; Cazenave, Jean-Pierre; Devine, Dana V; Gachet, Christian; Greinacher, Andreas; Lion, Niels; Schubert, Peter; Steil, Leif; Thiele, Thomas; Tissot, Jean-Daniel; Völker, Uwe; Zolla, Lello

    2014-04-01

    Pathogen inactivation (PI) of platelet concentrates (PCs) reduces the proliferation/replication of a large range of bacteria, viruses, and parasites as well as residual leucocytes. Pathogen-inactivated PCs were evaluated in various clinical trials showing their efficacy and safety. Today, there is some debate over the hemostatic activity of treated PCs as the overall survival of PI platelets seems to be somewhat reduced, and in vitro measurements have identified some alterations in platelet function. Although the specific lesions resulting from PI of PCs are still not fully understood, proteomic studies have revealed potential damages at the protein level. This review merges the key findings of the proteomic analyses of PCs treated by the Mirasol Pathogen Reduction Technology, the Intercept Blood System, and the Theraflex UV-C system, respectively, and discusses the potential impact on the biological functions of platelets. The complementarities of the applied proteomic approaches allow the coverage of a wide range of proteins and provide a comprehensive overview of PI-mediated protein damage. It emerges that there is a relatively weak impact of PI on the overall proteome of platelets. However, some data show that the different PI treatments lead to an acceleration of platelet storage lesions, which is in agreement with the current model of platelet storage lesion in pathogen-inactivated PCs. Overall, the impact of the PI treatment on the proteome appears to be different among the PI systems. Mirasol impacts adhesion and platelet shape change, whereas Intercept seems to impact proteins of intracellular platelet activation pathways. Theraflex influences platelet shape change and aggregation, but the data reported to date are limited. This information provides the basis to understand the impact of different PI on the molecular mechanisms of platelet function. Moreover, these data may serve as basis for future developments of PI technologies for PCs. Further studies

  1. Platelet lysate and chondroitin sulfate loaded contact lenses to heal corneal lesions.

    PubMed

    Sandri, Giuseppina; Bonferoni, Maria Cristina; Rossi, Silvia; Delfino, Alessio; Riva, Federica; Icaro Cornaglia, Antonia; Marrubini, Giorgio; Musitelli, Giorgio; Del Fante, Claudia; Perotti, Cesare; Caramella, Carla; Ferrari, Franca

    2016-07-25

    Hemoderivative tear substitutes contain various ephiteliotrophic factors, such as growth factors (GF), involved in ocular surface homeostasis without immunogenic properties. The aim of the present work was the loading of platelet lysate into contact lenses to improve the precorneal permanence of platelet lysate growth factors on the ocular surface to enhance the treatment of corneal lesions. To this purpose, chondroitin sulfate, a sulfated glycosaminoglycan, which is normally present in the extracellular matrix, was associated with platelet lysate. In fact, chondroitin sulfate is capable of electrostatic interaction with positively charged growth factors, in particular, with bFGF, IGF, VEGF, PDGF and TGF-β, resulting in their stabilization and reduced degradation in solution. In the present work, various types of commercially available contact lenses have been loaded with chondroitin sulfate or chondroitin sulfate in association with platelet lysate to achieve a release of growth factors directly onto the corneal surface lesions. One type of contact lenses (PureVision(®)) showed in vitro good proliferation properties towards corneal cells and were able to enhance cut closure in cornea constructs. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Initial blood storage experiment

    NASA Technical Reports Server (NTRS)

    Surgenor, Douglas MACN.

    1988-01-01

    The possibility of conducting experiments with the formed elements of the blood under conditions of microgravity opens up important opportunities to improve the understanding of basic formed element physiology, as well as, contribution to improved preservation of the formed elements for use in transfusion. The physiological, biochemical, and physical changes of the membrane of the erythrocyte, platelet, and leukocyte was studied during storage under two specific conditions: standard blood bank conditions and microgravity, utilizing three FDA approved plastic bags. Storage lesions; red cell storage on Earth; platelet storage on Earth; and leukocyte storage Earth were examined. The interaction of biomaterials and blood cells was studied during storage.

  3. Platelet utilization: a Canadian Blood Services research and development symposium.

    PubMed

    Webert, Kathryn E; Alam, Asim Q; Chargé, Sophie B; Sheffield, William P

    2014-04-01

    Considerable progress has been made in recent years in understanding platelet biology and in strengthening the clinical evidence base around platelet transfusion thresholds and appropriate platelet dosing. Platelet alloimmunization rates have also declined. Nevertheless, controversies and uncertainties remain that are relevant to how these products can best be used for the benefit of platelet transfusion recipients. Platelets are unique among the blood products directly derived from whole blood or apheresis donations in requiring storage, with shaking, at ambient temperature. Storage is accordingly constrained between the need to limit the growth of any microbes in the product and the need to minimize losses in platelet function associated with storage. Proteomic and genomic approaches are being applied to the platelet storage lesion. Platelet inventory management is made challenging by these constraints. Although bacterial screening has enhanced the safety of platelet transfusions, pathogen reduction technology may offer further benefits. Continuing clinical investigations are warranted to understand the value of transfusing platelets prophylactically or only in response to bleeding in different patient groups and how best to manage the most grievously injured trauma patients. Patients refractory to platelet transfusions also require expert clinical management. The engineering of platelet substitute products is an active area of research, but considerable hurdles remain before any clinical uses may be contemplated. Roles for platelets in biological areas distinct from hemostasis are also emerging. Platelet utilization is variably affected by all of the above factors, by demographic changes, by new medications, and by new patient care approaches. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Evaluation of in vitro storage characteristics of cold stored platelet concentrates with N acetylcysteine (NAC).

    PubMed

    Handigund, Mallikarjun; Bae, Tae Won; Lee, Jaehyeon; Cho, Yong Gon

    2016-02-01

    Platelets play a vital role in hemostasis and thrombosis, and their demand and usage has multiplied many folds over the years. However, due to the short life span and storage constraints on platelets, it is allowed to store them for up to 7 days at room temperature (RT); thus, there is a need for an alternative storage strategy for extension of shelf life. Current investigation involves the addition of 50 mM N acetylcysteine (NAC) in refrigerated concentrates. Investigation results revealed that addition of NAC to refrigerated concentrates prevented platelet activation and reduced the sialidase activity upon rewarming as well as on prolonged storage. Refrigerated concentrates with 50 mM NAC expressed a 23.91 ± 6.23% of CD62P (P-Selectin) and 22.33 ± 3.42% of phosphotidylserine (PS), whereas RT-stored platelets showed a 46.87 ± 5.23% of CD62P and 25.9 ± 6.48% of phosphotidylserine (PS) after 5 days of storage. Further, key metabolic parameters such as glucose and lactate accumulation indicated reduced metabolic activity. Taken together, investigation and observations indicate that addition of NAC potentially protects refrigerated concentrates by preventing platelet activation, stabilizing sialidase activity, and further reducing the metabolic activity. Hence, we believe that NAC can be a good candidate for an additive solution to retain platelet characteristics during cold storage and may pave the way for extension of storage shelf life. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Manufacture of pooled platelets in additive solution and storage in an ELX container after an overnight warm temperature hold of platelet-rich plasma.

    PubMed

    Alhumaidan, Hiba; Cheves, Tracey; Holme, Stein; Sweeney, Joseph D

    2011-10-01

    The processing of whole blood-derived platelet-rich plasma (PRP) to a platelet concentrate and platelet-poor plasma is currently performed within 8 hours to comply with the requirements to manufacture fresh frozen plasma. Maintaining PRP at room temperature for a longer period can have the advantage of shifting the completion of component manufacture onto day shifts. Pairs of ABO-identical prepooled platelets were manufactured by the PRP method, using the current approach with platelet storage in a CLX HP container (Pall Medical, Covina, CA) and plasma, or a novel approach with an 18- to a 24-hour room temperature hold of the PRP and the manufacture of pooled platelets in a glucose-containing additive solution (AS) and storage in a new ELX container (Pall Medical). Standard in vitro assays were performed on days 2, 5, and 7. The results showed that the AS platelets in ELX have in vitro characteristics that are equivalent or superior to those of the standard product.

  6. Improved extension of platelet storage in a polyolefin container with higher oxygen permeability.

    PubMed

    Yuasa, Takeshi; Ohto, Hitoshi; Yasunaga, Reiko; Kai, Takanori; Shirahama, Noriaki; Ogata, Takashi

    2004-07-01

    This study evaluated a newly developed polyolefin bag, which has a 50%/m(2) higher oxygen permeability to extend the shelf-life of platelets. Single-donor aphaeresis platelets were pooled, separated equally into two bags, PO-80 (0.8 l capacity) and KBP-PO (1 l capacity) for control, and stored in plasma for up to 7 d. Platelet biochemical and functional parameters were monitored in bags containing high (4.2 x 10(11)/250 ml/bag, n = 9) and low (2.0 x 10(11)/200 ml/bag, n = 3) concentrations of platelets over the storage period. After 7 d of storage, the PO-80 bags containing high concentrations of platelets had a better pH (mean pH 6.74) than those stored in KBP-PO (pH 6.32, P < 0.01); none of the nine PO-80 bags with a high platelet concentration had a pH below 6.2, compared with four of nine controls (P < 0.05). Similarly, lactate values were 20.19 mmol/l and 28.09 mmol/l respectively (P < 0.05). Aerobic metabolism was maintained better with greater O(2) consumption and less lactate generation in high-platelet concentration PO-80 bags than in the control bags. A significant difference was also found in pH, pCO(2) and lactate levels between the two bags containing low concentrations of platelets during the 7-d period. The in vitro characteristics of platelets declined less over 7 d when stored in a higher oxygen permeable container than in a marketed bag.

  7. Congenital platelet function defects

    MedlinePlus

    Platelet storage pool disorder; Glanzmann's thrombasthenia; Bernard-Soulier syndrome; Platelet function defects - congenital ... This disorder may also cause severe bleeding. Platelet storage pool disorder (also called platelet secretion disorder) occurs ...

  8. Improved platelet survival after cold storage by prevention of glycoprotein Ibα clustering in lipid rafts

    PubMed Central

    Gitz, Eelo; Koekman, Cornelis A; van den Heuvel, Dave J.; Deckmyn, Hans; Akkerman, Jan W.; Gerritsen, Hans C.; Urbanus, Rolf T.

    2012-01-01

    Background Storing platelets for transfusion at room temperature increases the risk of microbial infection and decreases platelet functionality, leading to out-date discard rates of up to 20%. Cold storage may be a better alternative, but this treatment leads to rapid platelet clearance after transfusion, initiated by changes in glycoprotein Ibα, the receptor for von Willebrand factor. Design and Methods: We examined the change in glycoprotein Ibα distribution using Förster resonance energy transfer by time-gated fluorescence lifetime imaging microscopy. Results Cold storage induced deglycosylation of glycoprotein Ibα ectodomain, exposing N-acetyl-Dglucosamine residues, which sequestered with GM1 gangliosides in lipid rafts. Raft-associated glycoprotein Ibα formed clusters upon binding of 14-3-3ζ adaptor proteins to its cytoplasmic tail, a process accompanied by mitochondrial injury and phosphatidyl serine exposure. Cold storage left glycoprotein Ibα surface expression unchanged and although glycoprotein V decreased, the fall did not affect glycoprotein Ibα clustering. Prevention of glycoprotein Ibα clustering by blockade of deglycosylation and 14-3-3ζ translocation increased the survival of cold-stored platelets to above the levels of platelets stored at room temperature without compromising hemostatic functions. Conclusions We conclude that glycoprotein Ibα translocates to lipid rafts upon cold-induced deglycosylation and forms clusters by associating with 14-3-3ζ. Interference with these steps provides a means to enable cold storage of platelet concentrates in the near future. PMID:22733027

  9. Ultraviolet-Based Pathogen Inactivation Systems: Untangling the Molecular Targets Activated in Platelets

    PubMed Central

    Schubert, Peter; Johnson, Lacey; Marks, Denese C.; Devine, Dana V.

    2018-01-01

    Transfusions of platelets are an important cornerstone of medicine; however, recipients may be subject to risk of adverse events associated with the potential transmission of pathogens, especially bacteria. Pathogen inactivation (PI) technologies based on ultraviolet illumination have been developed in the last decades to mitigate this risk. This review discusses studies of platelet concentrates treated with the current generation of PI technologies to assess their impact on quality, PI capacity, safety, and clinical efficacy. Improved safety seems to come with the cost of reduced platelet functionality, and hence transfusion efficacy. In order to understand these negative impacts in more detail, several molecular analyses have identified signaling pathways linked to platelet function that are altered by PI. Because some of these biochemical alterations are similar to those seen arising in the context of routine platelet storage lesion development occurring during blood bank storage, we lack a complete picture of the contribution of PI treatment to impaired platelet functionality. A model generated using data from currently available publications places the signaling protein kinase p38 as a central player regulating a variety of mechanisms triggered in platelets by PI systems. PMID:29868586

  10. Evaluation of Dried Storage of Platelets and RBC for Transfusion: Lyophilization and other Dehydration Techniques.

    DTIC Science & Technology

    1992-11-02

    linking agents. Water replacement molecules, such as trehalose or sucrose at concentrations up to 1 M, did not suffice to stabilize platelets for...concentration of albumin (5% w/v) or trehalose (250 mM - I M) is required in the final suspension prior to freeze-drying to ensure platelet yield and...structurally or functionally intact platelets post- rehydration; the presence of albumin or trehalose raises this yield to 90-100%. Lvophilization and Storage

  11. Platelet storage in Fresenius/NPBI polyolefin and BTHC-PVC bags: a direct comparison.

    PubMed

    Hornsey, V S; McColl, K; Drummond, O; Macgregor, I R; Prowse, C V

    2008-08-01

    New platelet storage systems, such as changes in the plastic of the storage bags, require validation. In this study, pooled buffy coat platelets stored in Fresenius/NPBI polyolefin bags were compared with those stored in Fresenius/NPBI butyryl-trihexyl citrate (BTHC) plasticized polyvinyl chloride (PVC). The CompoSelect thrombocyte polishing filter system (1000 mL polyolefin bag) and the CompoStop F730 system (1300 mL BTHC-PVC bag) were used to prepare paired, plasma-suspended, buffy coat platelet concentrates. Samples were taken up to day 7 for in vitro analysis. In a separate experiment, 12 units were prepared using the CompoStop F730 system and samples taken after leucofiltration for FXIIa assay. By day 7, platelet concentrates stored in BTHC-PVC demonstrated significantly higher pH levels (7.32 +/- 0.05 vs. 7.26 +/- 0.05) and a greater degree of cell lysis as shown by increased lactate dehydrogenase levels (497 +/- 107 vs. 392 +/- 81 U L(-1)). The supernatants contained higher concentrations of soluble P-selectin and the chemokine 'regulated on activation, normal T-cell expressed and presumably secreted', which are released from the alpha-granules during activation. The ATP concentrations were significantly lower in BTHC-PVC. Platelet counts, mean platelet volume and hypotonic shock response were similar for both bags. FXIIa antigen concentrations were 0.6 +/- 0.2 ng mL(-1) indicating that activation of the contact factor pathway had not occurred. Although the CompoStop F730 leucoreduction filter did not activate the contact system, platelets stored in 100% plasma in BTHC-PVC bags demonstrated different in vitro characteristics from those stored in polyolefin. Further work is required to demonstrate whether these differences will affect in vivo recovery and survival.

  12. Refrigeration and cryopreservation of platelets differentially affect platelet metabolism and function: a comparison with conventional platelet storage conditions.

    PubMed

    Johnson, Lacey; Tan, Shereen; Wood, Ben; Davis, April; Marks, Denese C

    2016-07-01

    Alternatives to room temperature storage of platelets (PLTs) may be beneficial to extend the limited shelf life and support transfusion logistics in rural and military areas. The aim of this study was to assess the morphologic, metabolic, and functional aspects of PLTs stored at room temperature or in refrigerated conditions or cryopreserved. A three-arm pool-and-split study was carried out using buffy coat-derived PLTs stored in 30% plasma/70% SSP+. The three matched treatment arms were room temperature stored (20-24°C), cold-stored (2-6°C), and cryopreserved (-80°C with dimethyl sulfoxide). Liquid-stored PLTs were tested over a 21-day period, while cryopreserved PLTs were examined immediately after thawing and after 6 and 24 hours of storage at room temperature. Cold-stored and cryopreserved PLTs underwent a significant shape change, although the cryopreserved PLTs appeared to recover from this during subsequent storage. Glycolytic metabolism was reduced in cold-stored PLTs, but accelerated in cryopreserved PLTs, while oxidative phosphorylation was negatively affected by both storage conditions. PLT aggregation was potentiated by cold storage and diminished by cryopreservation in comparison to room temperature-stored PLTs. Cold storage and cryopreservation resulted in faster clot formation (R-time; thromboelastography), which was associated with an increase in microparticles. Cold storage and cryopreservation of PLTs led to morphologic and metabolic changes. However, storage under these conditions appears to maintain or even enhance certain aspects of in vitro PLT function. © 2016 AABB.

  13. Pathogen inactivation by riboflavin and ultraviolet light illumination accelerates the red blood cell storage lesion and promotes eryptosis.

    PubMed

    Qadri, Syed M; Chen, Deborah; Schubert, Peter; Perruzza, Darian L; Bhakta, Varsha; Devine, Dana V; Sheffield, William P

    2017-03-01

    Pathogen reduction treatment using riboflavin and ultraviolet light illumination (Mirasol) effectively reduces the risk of transfusion-transmitted infections. This treatment is currently licensed for only platelets and plasma products, while its application to whole blood (WB) to generate pathogen-inactivated red blood cells (RBCs) is under development. RBC storage lesion, constituting numerous morphologic and biochemical changes, influences RBC quality and limits shelf life. Stored RBCs further show enhanced susceptibility to RBC programmed cell death (eryptosis) characterized by increased cytosolic Ca 2+ -provoked membrane phosphatidylserine (PS) externalization. Using a "pool-and-split" approach, we examined multiple variables of RBC storage lesion and eryptosis in RBC units, derived from Mirasol-treated or untreated WB, after 4 to 42 days of storage, under blood bank conditions. In comparison to untreated RBC units, Mirasol treatment significantly altered membrane microvesiculation, supernatant hemoglobin, osmotic fragility, and intracellular adenosine triphosphate levels but did not influence membrane CD47 expression and 2,3-diphosphoglycerate levels. Mirasol-treated RBCs showed significantly higher PS exposure after 42, but not after not more than 21, days of storage, which was accompanied by enhanced cytosolic Ca 2+ activity, ceramide abundance, and oxidative stress, but not p38 kinase activation. Mirasol treatment significantly augmented PS exposure, Ca 2+ entry, and protein kinase C activation after energy depletion, a pathophysiologic cell stressor. Mirasol-treated RBCs were, however, more resistant to cell shrinkage. Prolonged storage of Mirasol-treated RBCs significantly increases the proportion of eryptotic RBCs, while even short-term storage enhances the susceptibility of RBCs to stress-induced eryptosis, which could reduce posttransfusion RBC recovery in patients. © 2016 AABB.

  14. Management of an endo-perio lesion in an immature tooth using autologous platelet-rich fibrin: a case report.

    PubMed

    Nagaveni, N B; Kumari, K Nandini; Poornima, P; Reddy, V V Subba

    2015-01-01

    Treatment of an endo-perio lesion involving a non-vital young permanent tooth is a highly challenging task to Pediatric Dentists. There is a quest for the newer biological approach to management of these lesions as traditional methods have various disadvantages. Recently, platelet-rich fibrin (PRF), a second-generation platelet concentrate, is rich in growth factors have been used in the periodontal regeneration procedure. The purpose of this paper is to describe the efficacy of PRF in the treatment of a deep intra bony defect associated with an endo-perio lesion in an immature right mandibular first premolar of 12-year-old female patient. A freshly prepared autologous PRF membrane was placed in the bony defect following debridement. Clinical and radiographic follow-up were performed at regular intervals that revealed absence of pain, gain in clinical attachment level, reduction in probing depth, and excellent bone regeneration indicating successful outcome.

  15. Comparison of the platelet-rich plasma and buffy coat protocols for preparation of canine platelet concentrates.

    PubMed

    Hoareau, Guillaume L; Jandrey, Karl E; Burges, Julie; Bremer, Daphne; Tablin, Fern

    2014-12-01

    Platelet (PLT) concentrates (PC) can be produced via the buffy coat (BC) or platelet-rich plasma (PRP) protocols. The 2 methods have not been compared with canine blood. The aims of the study were to compare the PLT, WBC, and RBC concentrations, in vitro PLT function, and markers of platelet storage lesion (PSL) in canine PC generated by 2 different protocols, and determine microbial growth throughout storage. PC from 8 healthy donor dogs were produced using 2 standard protocols, PRP and BC. PLT, WBC, and RBC counts, optical aggregometry assays, and PSL markers (pH, pCO2 , HCO3 , lactate and glucose concentrations, and LDH activity) were determined on storage days 0, 1, 3, 5, and 7. Aerobic and anaerobic bacterial cultures were also performed. Mean PLT counts were comparable between protocols and remained stable throughout storage up to day 7, while median WBC and RBC counts on day 0 were significantly higher in the BC-PC group (17,800 WBCs/μL; 195,000 RBCs/μL) than in the PRP-PC group (200 WBCs/μL; 10,000 RBCs/μL) (P = .012). In PRP-PC aggregometry, the median slope and amplitude in response to γ-thrombin and convulxin (+ ADP) were significantly decreased, and virtually absent in BC-PC during storage. PSL markers (lactate, LDH activity) were higher in BC-PC. Aerobic bacterial growth was observed in 2 PRP-PC and 1 BC-PC. This in vitro study suggests that PRP-PC had lesser WBC and RBC contamination and superior PLT function compared with BC-PC. In vivo studies are required to address safety and efficacy of PRP-PC. © 2014 American Society for Veterinary Clinical Pathology.

  16. Platelet-, leucocyte- and red cell-derived microparticles in stored whole blood, with and without leucofiltration, with and without ionising radiation

    PubMed Central

    Saito, Shunnichi; Ngoma, Alain M.; Ono, Takako; Ohto, Hitoshi

    2018-01-01

    Background Storage lesion, including microparticle formation, has been partially characterised in whole blood, but not in all combinations of pre-storage leucofiltration and/or irradiation. Materials and methods Single-donor whole blood products were processed into four subunits: with and without leucofiltration, with and without X-irradiation (25 Gy). Platelet-, leucocyte-, and erythrocyte-derived microparticles and free haemoglobin were measured periodically throughout 42 days of storage. Results Pre-storage leucofiltration substantially reduced platelet- and leucocyte-derived microparticle counts throughout storage. Irradiation, in contrast, had no significant effect on microparticle counts. A gate for all microparticles showed a substantial time-dependent increase in unfiltered whole blood. A time-dependent increase in free haemoglobin was greatest in unfiltered, irradiated whole blood. Discussion This study indicates that leucofiltration can prevent the formation of leucocyte- and platelet-derived microparticles, and might reduce haemolysis in irradiated whole blood, either by removing factors that provoke haemolysis, or by selective retention of senescent or effete red cells most prone to haemolysis. PMID:27893349

  17. Platelet-, leucocyte- and red cell-derived microparticles in stored whole blood, with and without leucofiltration, with and without ionising radiation.

    PubMed

    Saito, Shunnichi; Nollet, Kenneth E; Ngoma, Alain M; Ono, Takako; Ohto, Hitoshi

    2018-02-01

    Storage lesion, including microparticle formation, has been partially characterised in whole blood, but not in all combinations of pre-storage leucofiltration and/or irradiation. Single-donor whole blood products were processed into four subunits: with and without leucofiltration, with and without X-irradiation (25 Gy). Platelet-, leucocyte-, and erythrocyte-derived microparticles and free haemoglobin were measured periodically throughout 42 days of storage. Pre-storage leucofiltration substantially reduced platelet- and leucocyte-derived microparticle counts throughout storage. Irradiation, in contrast, had no significant effect on microparticle counts. A gate for all microparticles showed a substantial time-dependent increase in unfiltered whole blood. A time-dependent increase in free haemoglobin was greatest in unfiltered, irradiated whole blood. This study indicates that leucofiltration can prevent the formation of leucocyte- and platelet-derived microparticles, and might reduce haemolysis in irradiated whole blood, either by removing factors that provoke haemolysis, or by selective retention of senescent or effete red cells most prone to haemolysis.

  18. Management of an endo perio lesion in a maxillary canine using platelet-rich plasma concentrate and an alloplastic bone substitute.

    PubMed

    Singh, Sangeeta

    2009-05-01

    To evaluate the efficacy of platelet-rich plasma concentrate in the management of a cirumferential, infrabony defect associated with an endoperio lesion in a maxillary canine. A 45 year-old male patient with an endoperio lesion in the left maxillary canine was initially treated with endodontic therapy. Following the endodontic treatment, the circumferential, infrabony defect was treated using platelet-rich plasma and an alloplastic bone substitute. At the end of three months, there was a gain in the clinical attachment level and reduction in probing depth. Radiographic evidence showed that there was significant bony fill. The results were maintained at the time of recall nine months later.

  19. Management of an endo perio lesion in a maxillary canine using platelet-rich plasma concentrate and an alloplastic bone substitute

    PubMed Central

    Singh, Sangeeta

    2009-01-01

    To evaluate the efficacy of platelet-rich plasma concentrate in the management of a cirumferential, infrabony defect associated with an endoperio lesion in a maxillary canine. A 45 year-old male patient with an endoperio lesion in the left maxillary canine was initially treated with endodontic therapy. Following the endodontic treatment, the circumferential, infrabony defect was treated using platelet-rich plasma and an alloplastic bone substitute. At the end of three months, there was a gain in the clinical attachment level and reduction in probing depth. Radiographic evidence showed that there was significant bony fill. The results were maintained at the time of recall nine months later. PMID:20407658

  20. Superior integrin activating capacity and higher adhesion to fibrinogen matrix in buffy coat-derived platelet concentrates (PCs) compared to PRP-PCs.

    PubMed

    Beshkar, Pezhman; Hosseini, Ehteramolsadat; Ghasemzadeh, Mehran

    2018-02-01

    Regardless of different sources, methods or devices which are applied for preparation of therapeutic platelets, these products are generally isolated from whole blood by the sedimentation techniques which are based on PRP or buffy coat (BC) separation. As a general fact, platelet preparation and storage are also associated with some deleterious changes that known as platelet storage lesion (PSL). Although these alternations in platelet functional activity are aggravated during storage, whether technical issues within preparation can affect integrin activation and platelet adhesion to fibrinogen were investigated in this study. PRP- and BC-platelet concentrates (PCs) were subjected to flowcytometry analysis to examine the expression of platelet activation marker, P-selectin as well as active confirmation of the GPIIb/IIIa (α IIb β 3 ) on day 0, 1, 3 and 5 post-storage. Platelet adhesion to fibrinogen matrix was evaluated by fluorescence microscopy. Glucose concentration and LDH activity were also measured by colorimetric methods. The increasing P-selectin expression during storage was in a reverse correlation with PAC-1 binding (r = -0.67; p = .001). PRP-PCs showed the higher level of P-selectin expression than BC-PCs, whereas the levels of PAC-1 binding and platelet adhesion to fibrinogen matrix were significantly lower in PRP-PCs. Higher levels of active confirmation of the GPIIb/IIIa in BC-PCs were also associated with greater concentration of glucose in these products. We demonstrated the superior capacities of integrin activation and adhesion to fibrinogen for BC-PCs compared to those of PRP-PCs. These findings may provide more advantages for BC method of platelet preparation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. RED BLOOD CELL STORAGE LESION

    PubMed Central

    Kor, Daryl J.; Van Buskirk, Camille M; Gajic, Ognjen

    2009-01-01

    The past two decades have witnessed increased scrutiny regarding efficacy and risk of the once unquestioned therapy of red blood cell (RBC) transfusion. Simultaneously, a variety of changes have been identified within the RBC and storage media during RBC preservation that are correlated with reduced tissue oxygenation and transfusion-associated adverse effects. These alterations are collectively termed the storage lesion and include extensive biochemical, biomechanical, and immunologic changes involving cells of diverse origin. Time-dependent falls is 2,3-diphosphoglycerate, intracellular RBC adenosine triphosphate, and nitric oxide have been shown to impact RBC deformability and delivery of oxygen to the end-organ. The accumulation of biologic response modifiers such as soluble CD40 ligand (sCD40L), lyso-phosphatidylcholine (lyso-PC), and Regulated on Activation, Normal T-cell Expressed and Secreted (RANTES) have been associated with altered recipient immune function as well. This review will address the alterations occurring within the RBC and storage media during RBC preservation and will address the potential clinical consequence thereof.

  2. Platelet biomechanics, platelet bioenergetics, and applications to clinical practice and translational research.

    PubMed

    George, Mitchell J; Bynum, James; Nair, Prajeeda; Cap, Andrew P; Wade, Charles E; Cox, Charles S; Gill, Brijesh S

    2018-07-01

    The purpose of this review is to explore the relationship between platelet bioenergetics and biomechanics and how this relationship affects the clinical interpretation of platelet function devices. Recent experimental and technological advances highlight platelet bioenergetics and biomechanics as alternative avenues for collecting clinically relevant data. Platelet bioenergetics drive energy production for key biomechanical processes like adhesion, spreading, aggregation, and contraction. Platelet function devices like thromboelastography, thromboelastometry, and aggregometry measure these biomechanical processes. Platelet storage, stroke, sepsis, trauma, or the activity of antiplatelet drugs alters measures of platelet function. However, the specific mechanisms governing these alterations in platelet function and how they relate to platelet bioenergetics are still under investigation.

  3. Biochemical Storage Lesions Occurring in Nonirradiated and Irradiated Red Blood Cells: A Brief Review

    PubMed Central

    Adams, F.; Bellairs, G.; Bird, A. R.; Oguntibeju, O. O.

    2015-01-01

    Red blood cells undergo a series of biochemical fluctuations during 35–42-day storage period at 1°C to 6°C. The sodium/potassium pump is immobilised causing a decrease in intracellular potassium with an increase in cytoplasmic sodium levels, glucose levels decline, and acidosis occurs as a result of low pH levels. The frailty of stored erythrocytes triggers the formation of haemoglobin-containing microparticles and the release of cell-free haemoglobin which may add to transfusion difficulties. Lipid peroxidation, oxidative stress to band 3 structures, and other morphological and structural molecular changes also occur leading to spheroechinocytes and osmotic fragility. These changes that transpire in the red cells during the storage period are referred to as “storage lesions.” It is well documented that gamma irradiation exacerbates storage lesions and the reports of increased potassium levels leading to adverse reactions observed in neonates and infants have been of particular concern. There are, however, remarkably few systematic studies comparing the in vitro storage lesions of irradiated and nonirradiated red cell concentrates and it has been suggested that the impact of storage lesions on leucocyte reduced red blood cell concentrate (RBCC) is incomplete. The review examines storage lesions in red blood cells and their adverse effects in reference to blood transfusion. PMID:25710038

  4. Previous Cryopreservation Alters the Natural History of the Red Blood Cell Storage Lesion.

    PubMed

    Chang, Alex L; Hoehn, Richard S; Jernigan, Peter; Cox, Daniel; Schreiber, Martin; Pritts, Timothy A

    2016-09-01

    During storage, packed red blood cells (pRBCs) undergo a number of biochemical, metabolic, and morphologic changes, collectively known as the "storage lesion." We aimed to determine the effect of cryopreservation on the red blood cell storage lesion compared with traditional 4°C storage. Previously cryopreserved human pRBCs were compared with age-matched never-frozen pRBCs obtained from the local blood bank. The development of the red cell storage lesion was evaluated after 7, 14, 21, 28, and 42 days of storage at 4°C in AS-3 storage medium. We measured physiological parameters including cell counts, lactic acid, and potassium concentrations as well as signs of eryptosis including loss of phosphatidylserine (PS) asymmetry, microparticle production, and osmotic fragility in hypotonic saline. Compared with controls, previously cryopreserved pRBC at 7 days of storage in AS-3 showed lower red cell counts (3.7 vs. 5.3 × 10 cells/μL, P < 0.01), hemoglobin (Hgb) (12.0 vs. 16.5 g/dL, P < 0.01), hematocrit (33.0% vs. 46.5%, P < 0.01), and pH (6.27 vs. 6.72, P < 0.01). Over 28 days of storage, storage cryopreserved pRBC developed increased cell-free Hgb (0.7 vs. 0.3 g/dL, P < 0.01), greater PS exposure (10.1% vs. 3.3%, P < 0.01), and microparticle production (30,836 vs. 1,802 MP/μL, P < 0.01). Previously cryopreserved cells were also less resistant to osmotic stress. The red blood cell storage lesion is accelerated in previously cryopreserved pRBC after thawing. Biochemical deterioration of thawed and deglycerolized red cells suggests that storage time before transfusion should be limited to achieve similar risk profiles as never-frozen standard liquid storage pRBC units.

  5. In vitro evaluation of COM.TEC apheresis platelet concentrates using a preparation set and pathogen inactivation over a storage period of five days.

    PubMed

    Moog, R; Fröhlich, A; Mayaudon, V; Lin, L

    2004-01-01

    The aim of the present study was to evaluate in vitro data on platelets collected by apheresis, processed on a preparation set followed by photochemical treatment (PCT). Fifteen single-donor platelet concentrates (PCs) were collected by apheresis (COM.TEC blood cell separator, Fresenius, Bad Homburg, Germany). The platelets were transferred to the preparation set and plasma was removed after centrifugation to resuspend the platelets in approximately 37% plasma and 63% platelet additive solution InterSol. PCT was done by exposing the platelets to amotosalen HCl followed by illumination with ultraviolet light. Blood cell counts and in vitro PLT function were measured up to 5 days. An average of 3.44 +/- 0.28 x 10(11) platelets were collected in a product volume of 351 +/- 21 mL. Plasma removal resulted in a mean platelet loss of 7.8%. After PCT, a progressive decrease in platelet function was observed. LDH level rose through storage (171 +/- 81 U/L) to levels approximating LDH levels observed post-collection (180 +/- 103 U/L). There was a gradual decrease of the platelets to respond to hypotonic shock response from 90 +/- 9 % post-plasma reduction to 48 +/- 16% at day 5. All PLT units met the European requirements for leukoreduction and the pH limit of 6.8 up to day 5 post-collection. The new preparation set was capable of producing platelet units meeting the requirements for PCT. Despite differences observed in in vitro platelet function parameters, PLTs at storage day 5 fit the German and European guidelines.

  6. Duration of platelet storage and outcomes of critically ill patients.

    PubMed

    Flint, Andrew; Aubron, Cécile; Bailey, Michael; Bellomo, Rinaldo; Pilcher, David; Cheng, Allen C; Hegarty, Colin; Reade, Michael C; McQuilten, Zoe

    2017-03-01

    The storage duration of platelet (PLT) units is limited to 5 to 7 days. This study investigates whether PLT storage duration is associated with patient outcomes in critically ill patients. This study was a retrospective analysis of critically ill patients admitted to the intensive care unit (ICU) of two hospitals in Australia who received one or more PLT transfusions from 2008 to 2014. Storage duration was approached in several different ways. Outcome variables were hospital mortality and ICU-acquired infection. Associations between PLT storage duration and outcomes were evaluated using multiple logistic regression and also by Cox regression. Among 2250 patients who received one or more PLT transfusions while in the ICU, the storage duration of PLTs was available for 64% of patients (1430). In-hospital mortality was 22.1% and ICU infection rate 7.2%. When comparing patients who received PLTs of a maximum storage duration of not more than 3, 4, or 5 days, there were no significant differences in baseline characteristics. After confounders were adjusted for, the storage duration of PLTs was not independently associated with mortality (4 days vs. ≤3 days, odds ratio [OR] 0.88, 95% confidence interval [CI] 0.59-1.30; 5 days vs. ≤3 days, OR 0.97, 95% CI 0.68-1.37) or infection (4 days vs. ≤3 days, OR 0.71, 95% CI 0.39-1.29; 5 days vs. ≤3 days, OR 1.11, 95% CI 0.67-1.83). Similar results were obtained regardless of how storage duration of PLTs was approached. In this large observational study in a heterogeneous ICU population, storage duration of PLTs was not associated with an increased risk of mortality or infection. © 2017 AABB.

  7. Toward correlating structure and mechanics of platelets.

    PubMed

    Sorrentino, Simona; Studt, Jan-Dirk; Horev, Melanie Bokstad; Medalia, Ohad; Sapra, K Tanuj

    2016-09-02

    The primary physiological function of blood platelets is to seal vascular lesions after injury and form hemostatic thrombi in order to prevent blood loss. This task relies on the formation of strong cellular-extracellular matrix interactions in the subendothelial lesions. The cytoskeleton of a platelet is key to all of its functions: its ability to spread, adhere and contract. Despite the medical significance of platelets, there is still no high-resolution structural information of their cytoskeleton. Here, we discuss and present 3-dimensional (3D) structural analysis of intact platelets by using cryo-electron tomography (cryo-ET) and atomic force microscopy (AFM). Cryo-ET provides in situ structural analysis and AFM gives stiffness maps of the platelets. In the future, combining high-resolution structural and mechanical techniques will bring new understanding of how structural changes modulate platelet stiffness during activation and adhesion.

  8. Storage of Buffy-coat-derived platelets in additive solutions: in vitro effects on platelets prepared by the novel TACSI system and stored in plastic containers with different gas permeability.

    PubMed

    Sandgren, P; Hild, M; Sjödin, A; Gulliksson, H

    2010-11-01

    The novel TACSI system is designed for automated preparation of platelets (PLTs) from pooled buffy coats (BCs). One TACSI device will handle 6 units at the same time. The aim of our in vitro study is to investigate the effects of using this automated equipment with subsequent storage in two different plastic containers and to compare these results with PLTs prepared by the OrbiSac system. Buffy-coat-derived PLTs (n=8) were prepared by using the TACSI system, including storage in polyvinyl chloride (PVC)-based plastic containers with di, n-decyl phthalate (DnDP) (TACSI R) and BTHC (TACSI T)-based plasticizers. As a reference, the OrbiSac System was used to prepare PLTs (n=8) with subsequent storage in a PVC plastic container with a citrate-based plasticizer (BTHC). In total, 16 TACSI and eight reference units, supplied by approximately 30% plasma and 70% SSP+, were analysed for various in vitro variables during the 7-day storage period. No significant difference in PLT counts, LDH, mean platelet volume (MPV) and adenosine triphosphate between the groups was detected. Glucose was lower (P<0·05) and lactate was higher (P<0·05) in TACSI R vs. OrbiSac. With exception of day 7 (P<0·05 TACSI R vs. OrbiSac), HSR reactivity were not different between groups. Extent of shape change was lower and CD62P higher in TACSI T when compared with TACSI R and OrbiSac units (P<0·05). pH was maintained at >6·8 (day 7) and swirling remained at the highest level (score=2) for all units throughout storage. Platelets prepared by the TACSI system with subsequent storage in two different PVC-based plastic containers were equivalent to reference PLTs with regard to in vitro characteristics during 7 days of storage. © 2010 The Author(s). Vox Sanguinis © 2010 International Society of Blood Transfusion.

  9. Collection, storage, inspection and quality control of platelet concentrates obtained by apheresis: The situation in Spain.

    PubMed

    Castrillo, Azucena; Jimenez-Marco, Teresa; Arroyo, José L; Jurado, María L; Larrea, Luis; Maymo, Rosa M; Monge, Jorge; Muñoz, Carmen; Pajares, Ángel; Yáñez, Marta

    2017-06-01

    Diverse variables are involved in apheresis platelet collection, processing and storage. This survey shows how these are realized in Spain. An analysis of collected data was performed in a questionnaire completed by ten Transfusion Centers (TC) which perform between 50 and 520 apheresis procedures per month. This information comprises the procedures used to collect, inspect and store apheresis platelet concentrates (PC), and quality control data. Macroscopic inspection of PC is performed in all TC, especially during the first few hours post-collection and before distribution. The type of processor, duration of post-collection resting periods and temperature from the time of collection until distribution are similar in all TC. In 80% of TC, PC with small and scarce aggregates are distributed to transfusion services. The presence of clumps is influenced by type of processor, female donor, cold ambient temperature and collection of hyperconcentrated platelets, and is often recurrent in the same donor, although some TC have not found any influential variables. Overall, no objective inspection methods are followed, although there are exceptions. The degree of compliance with quality control parameters, such as the number of units studied, mean platelet yield, residual leukocyte counts and pH at expiry date, is acceptable in all TC. Compliance in terms of number of microbiological culture samples is variable. The usual practice in Spanish TC with respect to the collection, post-collection handling and storage of apheresis PC can be considered uniform, although some specific aspects of analyses should follow more objective methods. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Treatment of endo-periodontal lesion using leukocyte-platelet-rich fibrin. A case report

    PubMed Central

    Elgueta, Ricardo; Fuentes, Ramon

    2017-01-01

    Abstract Case Description: The main objective of this paper was to report the clinical effectiveness of leukocyte- platelet- rich fibrin (L-PRF) in the treatment of a combined endo-periodontal lesion of an upper first premolar. Clinical Findings: The tooth had a profound abfraction on the vestibular aspect and presented no mobility but revealed a deep pocket measuring of 11 mm on the mesial vestibular aspect and 14 mm on the mesial palatine aspect. The three dimensional image analysis showed total bone loss in the mesial aspect and an extensively bone loss of the vestibular aspect of the vestibular root. Treatment and Outcome: Endodontic treatment was performed and periodontal access surgery (surgical periodontal therapy) was done with the application of autologous L-PRF. Three month and 6 months after surgery, the cone beam computed tomography (CBCT) exams showed no bone regeneration in any aspect of the tooth. However, periodontal examination showed a significative improvement in the deepness of surcus. The mesial vestibular aspect had a deep pocket of 3 mm and 5 mm on the mesial palatine aspect showing a reduction in deepness of 8 mm and 9 mm, respectively. Clinical Relevance: The actual treatment for teeth with bad prognosis is the extraction and replacement with implants. Even though implants are capable of restore function and aesthetic, the abuse of this approach have led to the loss of teeth that could be successfully treated with a less invasive technique. The prognosis of teeth with endoperiodontal lesion is poor but could be enhanced with regenerative therapies. Until now there are no clinical trials and just four case report about the treatment of these teeth with platelet rich fibrin. PMID:29662262

  11. Apheresis platelet concentrates contain platelet-derived and endothelial cell-derived microparticles.

    PubMed

    Rank, A; Nieuwland, R; Liebhardt, S; Iberer, M; Grützner, S; Toth, B; Pihusch, R

    2011-02-01

    Microparticles (MP) are membrane vesicles with thrombogenic and immunomodulatory properties. We determined MP subgroups from resting platelets, activated platelets and endothelial cells in donors and apheresis platelet concentrates (PC). MP were double stained with annexin V and CD61 (platelet-derived MP; PMP), P-selectin or CD63 (MP from activated platelets) and CD144 plus E-selectin (endothelial cell-derived MP; EMP) and detected by flow cytometry in platelet donors (n=36) and apheresis PC (n=11; Trima™). PC contained MP, mainly from resting platelets [93% (90-95)], and minor fractions of PMP from activated platelets [P-selectin(+) or CD63(+); 4·8% (3·2-7·7) and 2·6% (2·0-4·0)]. Compared to donors, levels of annexin V+ MP, PMP, P-selectin(+) and CD63(+) MP were 1·7-, 2·3-, 8·6- and 3·1-fold higher in PC (all P<0·05). During storage (1-5 days), levels of annexin V+ MP and PMP did not increase, although small increases in the fraction of P-selectin(+) or CD63(+) MP occurred (both P<0·05). PC also contained EMP, which were 2·6- to 3·7-fold enriched in PC compared to donors (P<0·05). Transfusion of apheresis PC also results in transfusion of HLA-carrying PMP and EMP. This might counteract the aim of reducing transfused HLA load by leucodepletion. The increases in PMP exposing P-selectin or CD63 reflect mild platelet activation during storage. We conclude that in leucodepleted platelet apheresis using fluidized particle bed technology, MP are harvested mainly from the donor by apheresis. Improvement in apheresis technology might reduce MP load. © 2010 The Author(s). Vox Sanguinis © 2010 International Society of Blood Transfusion.

  12. pH modulation ameliorates the red blood cell storage lesion in a murine model of transfusion.

    PubMed

    Chang, Alex L; Kim, Young; Seitz, Aaron P; Schuster, Rebecca M; Pritts, Timothy A

    2017-05-15

    Prolonged storage of packed red blood cells (pRBCs) induces a series of harmful biochemical and metabolic changes known as the RBC storage lesion. RBCs are currently stored in an acidic storage solution, but the effect of pH on the RBC storage lesion is unknown. We investigated the effect of modulation of storage pH on the RBC storage lesion and on erythrocyte survival after transfusion. Murine pRBCs were stored in Additive Solution-3 (AS3) under standard conditions (pH, 5.8), acidic AS3 (pH, 4.5), or alkalinized AS3 (pH, 8.5). pRBC units were analyzed at the end of the storage period. Several components of the storage lesion were measured, including cell-free hemoglobin, microparticle production, phosphatidylserine externalization, lactate accumulation, and byproducts of lipid peroxidation. Carboxyfluorescein-labeled erythrocytes were transfused into healthy mice to determine cell survival. Compared with pRBCs stored in standard AS3, those stored in alkaline solution exhibited decreased hemolysis, phosphatidylserine externalization, microparticle production, and lipid peroxidation. Lactate levels were greater after storage in alkaline conditions, suggesting that these pRBCs remained more metabolically viable. Storage in acidic AS3 accelerated erythrocyte deterioration. Compared with standard AS3 storage, circulating half-life of cells was increased by alkaline storage but decreased in acidic conditions. Storage pH significantly affects the quality of stored RBCs and cell survival after transfusion. Current erythrocyte storage solutions may benefit from refinements in pH levels. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Unraveling the Gordian knot: red blood cell storage lesion and transfusion outcomes

    PubMed Central

    Tzounakas, Vassilis L.; Kriebardis, Anastasios G.; Seghatchian, Jerard; Papassideri, Issidora S.; Antonelou, Marianna H.

    2017-01-01

    What is following the impressive progress that has been made? During the last couple of years several tremors have shaken the field of Transfusion Medicine. The epicentres of those tremors were located on novel insights into the RBC storage lesion, on emerging connections between storage lesion and post-transfusion performance and effects, and on acknowledging that storage time is only one (rather than the most prominent) of the parameters which contribute to the progression of storage lesion in any given unit of blood. The optimisation of bio-preservation conditions emerged at the same time with all-new scientific knowledge gained by advances in research tools, implementation of technological innovations, and application of elegant in vitro and in vivo models of transfusion. Simultaneously, one after another, all the reported randomised clinical trials concluded, with spectacular consensus, that there is no significant difference in the rate of adverse clinical events (including death) among patients who underwent transfusion with fresh (and presumably good) or standard of care (and presumably bad) blood. The comparative analysis and comprehension of the aforementioned data would set the context for the next generation of research in blood transfusion science, since the need for safer and more efficient transfusions remains. PMID:28263169

  14. Previous cryopreservation alters the natural history of the red blood cell storage lesion

    PubMed Central

    Chang, Alex L.; Hoehn, Richard S.; Jernigan, Peter; Cox, Daniel; Schreiber, Martin; Pritts, Timothy A.

    2016-01-01

    Background During storage, packed red blood cells (pRBCs) undergo a number of biochemical, metabolic and morphologic changes, collectively known as the “storage lesion”. We aimed to determine the effect of cryopreservation on the red blood cell storage lesion compared to traditional 4°C storage. Methods Previously cryopreserved human packed red blood cells were compared to age matched never frozen packed red blood cells obtained from the local blood bank. The development of the red cell storage lesion was evaluated after 7, 14, 21, 28, and 42 days of storage at 4°C in AS-3 storage medium. We measured physiological parameters including cell counts, lactic acid and potassium concentrations as well as signs of eryptosis including loss of phosphatidylserine (PS) asymmetry, microparticle production and osmotic fragility in hypotonic saline. Results Compared to controls, previously cryopreserved pRBC at 7 days of storage in AS-3 showed lower red cell counts (3.7 vs 5.3 ×10^6 cells/uL, p(<0.01), hemoglobin (12.0 vs 16.5 g/dL, p<0.01), hematocrit (33.0 vs 46.5%, p<0.01), and pH (6.27 vs 6.72, p<0.01). Over 28 days of storage, storage cryopreserved pRBC developed increased cell free hemoglobin (0.7 vs 0.3 g/dL, p<0.01), greater PS exposure (10.1 vs 3.3%, p<0.01), and microparticle production (30,836 vs 1,802 MP/uL, p<0.01). Previously cryopreserved cells were also less resistant to osmotic stress. Conclusion The red blood cell storage lesion is accelerated in previously cryopreserved pRBC after thawing. Biochemical deterioration of thawed and deglycerolized red cells suggests that storage time prior to transfusion should be limited in order to achieve similar risk profiles as never frozen standard liquid storage pRBC units. PMID:27380532

  15. Additive solution-7 reduces the red blood cell cold storage lesion.

    PubMed

    Cancelas, Jose A; Dumont, Larry J; Maes, Lou A; Rugg, Neeta; Herschel, Louise; Whitley, Pamela H; Szczepiokowski, Zbigniew M; Siegel, Alan H; Hess, John R; Zia, Majid

    2015-03-01

    Transfusion of long-stored red blood cells (RBCs) is associated with decreased in vivo RBC recovery, delivery of RBC breakdown products, and increased morbidity and mortality. Reducing the burden of this RBC "storage lesion" is a major challenge in transfusion medicine. Additive solution-7 (AS-7) is a new RBC storage solution designed to improve RBC metabolism by providing phosphate and increasing buffering capacity. Storage quality in AS-7 was measured in a prospective, randomized, three-center trial using units of whole blood from healthy human subjects whose RBCs were stored for up to 56 days in AS-7 (n = 120) or for 42 days in the control solution AS-1 (n = 60). Hemolysis and shedding of protein-containing microvesicles were significantly reduced in RBCs stored in AS-7 for 42 and 56 days compared with RBCs stored in AS-1. Autologous in vivo recoveries of RBCs stored in AS-7 was 88 ± 5% at 42 days (n = 27) and 82 ± 3% at 56 days (n = 27), exceeding recoveries of RBCs stored in currently used solutions. Increasing the phosphate, pH range, and buffer capacity of a RBC storage system allowed RBCs to be stored better and longer than currently approved storage systems. AS-7 ameliorates the long-term storage lesion resulting in significantly increased viability in vitro and in vivo. © 2014 AABB.

  16. Scintigraphic detection of carotid atherosclerosis with indium-111-labeled autologous platelets

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Davis, H.H.; Siegel, B.A.; Sherman, L.A.

    1980-05-01

    Using autologous platelets labeled with indium-111-oxine, we studied the localization of platelets on arterial lesions by radionuclide scintigraphy in 34 patients with suspected cerebrovascular disease. The imaging results were compared with the findings of contrast angiography in 23 patients, 16 of whom were receiving antiplatelet and/or anticoagulant drugs during the platelet imaging study. Angiography demonstrated atherosclerotic lesions at 33 sites in the extracranial arteries of 16 of these patients. There was accumulation of /sup 111/In-platelets at 20 of these sites (61%) and at three other sites without definite angiographic abnormalities. Lesions with stenoses <50% were slightly more frequent than thosemore » with greater stenosis (68% vs 45%). The frequency of true-positive scintigraphic results was slightly higher in patients not treated with antithrombotic agents than in those on such drugs (70% vs 57%). Our results suggest that imaging with /sup 111/In-labeled autologous platelets may be useful for evaluating the pathophysiologic characteristics of atherosclerotic lesions in patients with cerebrovascular disease.« less

  17. Platelet-rich plasma as treatment for persistent ocular epithelial defects.

    PubMed

    Ronci, Corrado; Ferraro, Angelo Salvatore; Lanti, Alessandro; Missiroli, Filippo; Sinopoli, Silvia; Del Proposto, Gianpaolo; Cipriani, Chiara; De Felici, Cecilia; Ricci, Federico; Ciotti, Marco; Cudillo, Laura; Arcese, William; Adorno, Gaspare

    2015-06-01

    Platelet- rich plasma (PRP) exhibits regenerative proprieties in wound healing but the biochemical mechanisms are unclear. In this study, autologous PRP with a mean value of 338 × 10(3) platelets/µL was used to treat corneal lesions of different aetiology, while homologous PRP with 1 × 10(6) platelets/µL was used to treat cornel lesions induced by a graft versus host disease. The impact of platelet count on the levels of PDGF AA and BB, VEGF, and EGF in the two PRPs was evaluated after a cycle of freezing/thawing. Treated corneal lesions healed or improved. The levels of PDGF AA and BB, VEGF, and EGF in the autologous PRP raised from 296 ± 61; 201.8 ± 24; 53 ± 14 and 8.9 ± 2 to 1017 ± 253; 924.7 ± 222; 101 ± 46.5 and 174 ± 15.5 pg/mL, while in the homologous PRP were 3.4, 4.5, 3.2 and 2 folds higher, respectively. High level of platelet counts seems not required to treat corneal lesions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Platelet-rich fibrin, "a faster healing aid" in the treatment of combined lesions: A report of two cases.

    PubMed

    Karunakar, Parupalli; Prasanna, Jammula Surya; Jayadev, Matapathi; Shravani, Guniganti Sushma

    2014-09-01

    Anatomically the pulp and periodontium are connected through apical foramen, and the lateral, accessory, and furcal canals. Diseases of one tissue may affect the other. In the present case report with two cases, a primary periodontal lesion with secondary endodontic involvement is described. In both cases, root canal treatment was done followed by periodontal therapy with the use of platelet-rich fibrin (PRF) as the regenerative material of choice. PRF has been a breakthrough in the stimulation and acceleration of tissue healing. It is used to achieve faster healing of the intrabony defects. Absence of an intraradicular lesion, pain, and swelling, along with tooth stability and adequate radiographic bone fill at 9 months of follow-up indicated a successful outcome.

  19. Prolonging shelf-life of platelets by low-level laser

    NASA Astrophysics Data System (ADS)

    Zhang, Qi; Lu, Min; Wu, Mei X.

    2018-02-01

    It remains significant challenges to extend a shelf life of platelets beyond the conventional five days. Unlike red blood cells that can be stored at 4°C for a few weeks, platelets are stored at room temperature only, which results in a gradual loss of their quality owing to a switch of energy metabolism from aerobic oxidative phosphorylation toward anaerobic glycolysis. Given the well-documented beneficial effect of near infrared low-level laser (LLL) on mitochondrial functions in a variety of cells under stress, we explored a potential for LLL to extend the shelf life of platelets beyond the five days. We found that exposure of a platelet-containing storage bag to LLL at 830nm at 0.5J/cm2 prior to storage could significantly retain a pH value and viability of the platelets stored within the bag under a standard condition for eight days with improved quality compared to those platelets stored similarly for five days in controls. LLL inhibited reactive oxygen species (ROS) and lactate production, but sustained ATP production, mitochondrial membrane potential, and morphology in the stored platelets. While preserving their metabolic activity, LLL didn't activate platelets but increased their aggregation capacity and in vivo survival as suggested by similar levels of surface CD62p expression and enhanced agonist-induced aggregation and recovery following infusion in the presence compared to the absence of LLL treatment. This simple, addition-free, cost-effective, noninvasive laser illumination can be readily incorporated into the current platelet storage system to prolong shelf life of platelets with improved quality of stored platelets.

  20. Platelet chemokines in vascular disease

    PubMed Central

    Gleissner, Christian A.; von Hundelshausen, Philipp; Ley, Klaus

    2009-01-01

    Platelets are a rich source of different chemokines and express chemokine receptors. CXCL4 is highly abundant in platelets and involved in promoting monocyte arrest from rolling and monocyte differentiation to macrophages. CXCL4 can also associate with CCL5 and amplify its effect on monocytes. The megakaryocyte CXCL7 gene product is proteolytically cleaved into the strong neutrophil chemoattractant, NAP-2, which has also been implicated in repair cell homing to vascular lesions. Platelet adhesion can induce release of CCL2 and CXCL8 from endothelial cells. Conversely, the chemokines CCL17, CCL22 and CXCL12 made by other cells amplify platelet activation. Platelet chemokines enhance recruitment of various hematopoietic cells to the vascular wall, fostering processes such as neointima formation, atherosclerosis, and thrombosis but also vessel repair and regeneration after vascular injury. PMID:18723831

  1. Maintenance of storage properties of pediatric aliquots of apheresis platelets in fluoroethylene propylene containers.

    PubMed

    Skripchenko, Andrey; Myrup, Andrew; Thompson-Montgomery, Dedeene; Awatefe, Helen; Wagner, Stephen J

    2013-04-01

    Platelet (PLT) aliquots for pediatric use have been shown to retain in vitro properties when stored in gas-impermeable syringes for up to 6 hours. As an alternative, PLT aliquots can be stored for longer periods in containers used for storage of whole blood-derived PLTs. These containers are not available separate from whole blood collection sets and PLT volumes less than 35 mL either have not been evaluated or may be unsuitable for PLT storage. Gas-permeable fluoroethylene propylene (FEP) containers have been used in the storage of cell therapy preparations and are available in multiple sizes as single containers but have not been evaluated for PLT storage. A single apheresis unit was divided on Day 3 into small aliquots with volume ranging from 20 to 60 mL, transferred using a sterile connection device, and stored for an additional 2 days either in CLX (control) or in FEP containers. PLT storage properties of PLTs stored in FEP containers were compared to those stored in CLX containers. Standard PLT in vitro assays were performed (n =6). PLT storage properties were either similar to those of CLX containers or differed by less than 20% excepting carbon dioxide levels, which varied less than 60%. Pediatric PLT aliquots of 20, 30, and 60mL transferred on Day 3 into FEP cell culture containers adequately maintain PLT properties for an additional 2days of storage. © 2012 American Association of Blood Banks.

  2. Novel and unexpected clearance mechanisms for cold platelets

    PubMed Central

    Rumjantseva, Viktoria; Hoffmeister, Karin M.

    2015-01-01

    Storage at room temperature is limited to 5 days because of the risk of bacterial growth and loss of platelet functionality. Platelet refrigeration remains impossible, because once chilled, platelets are rapidly removed from circulation. Chilling platelets (<4 h) clusters glycoprotein (GP) Ibα receptors, and β2 integrins on hepatic macrophages recognize clustered βGlcNAc residues leading to rapid clearance of acutely chilled platelets. Prolonged refrigeration increases the exposure of galactose residues such that, unexpectedly, hepatocytes remove platelets using their asialoglycoprotein receptors. Here we review current knowledge of the mechanisms of platelet removal, the existing knowledge of refrigerated platelet function, and methods to preserve platelet concentrates long-term for transfusion. PMID:19932055

  3. Improving platelet transfusion safety: biomedical and technical considerations

    PubMed Central

    Garraud, Olivier; Cognasse, Fabrice; Tissot, Jean-Daniel; Chavarin, Patricia; Laperche, Syria; Morel, Pascal; Lefrère, Jean-Jacques; Pozzetto, Bruno; Lozano, Miguel; Blumberg, Neil; Osselaer, Jean-Claude

    2016-01-01

    Platelet concentrates account for near 10% of all labile blood components but are responsible for more than 25% of the reported adverse events. Besides factors related to patients themselves, who may be particularly at risk of side effects because of their underlying illness, there are aspects of platelet collection and storage that predispose to adverse events. Platelets for transfusion are strongly activated by collection through disposal equipment, which can stress the cells, and by preservation at 22 °C with rotation or rocking, which likewise leads to platelet activation, perhaps more so than storage at 4 °C. Lastly, platelets constitutively possess a very large number of bioactive components that may elicit pro-inflammatory reactions when infused into a patient. This review aims to describe approaches that may be crucial to minimising side effects while optimising safety and quality. We suggest that platelet transfusion is complex, in part because of the complexity of the “material” itself: platelets are highly versatile cells and the transfusion process adds a myriad of variables that present many challenges for preserving basal platelet function and preventing dysfunctional activation of the platelets. The review also presents information showing - after years of exhaustive haemovigilance - that whole blood buffy coat pooled platelet components are extremely safe compared to the gold standard (i.e. apheresis platelet components), both in terms of acquired infections and of immunological/inflammatory hazards. PMID:26674828

  4. Platelet-rich fibrin, “a faster healing aid” in the treatment of combined lesions: A report of two cases

    PubMed Central

    Karunakar, Parupalli; Prasanna, Jammula Surya; Jayadev, Matapathi; Shravani, Guniganti Sushma

    2014-01-01

    Anatomically the pulp and periodontium are connected through apical foramen, and the lateral, accessory, and furcal canals. Diseases of one tissue may affect the other. In the present case report with two cases, a primary periodontal lesion with secondary endodontic involvement is described. In both cases, root canal treatment was done followed by periodontal therapy with the use of platelet-rich fibrin (PRF) as the regenerative material of choice. PRF has been a breakthrough in the stimulation and acceleration of tissue healing. It is used to achieve faster healing of the intrabony defects. Absence of an intraradicular lesion, pain, and swelling, along with tooth stability and adequate radiographic bone fill at 9 months of follow-up indicated a successful outcome. PMID:25425831

  5. The clearance mechanism of chilled blood platelets.

    PubMed

    Hoffmeister, Karin M; Felbinger, Thomas W; Falet, Hervé; Denis, Cécile V; Bergmeier, Wolfgang; Mayadas, Tanya N; von Andrian, Ulrich H; Wagner, Denisa D; Stossel, Thomas P; Hartwig, John H

    2003-01-10

    Platelet transfusion is a very common lifesaving medical procedure. Not widely known is the fact that platelets, unlike other blood cells, rapidly leave the circulation if refrigerated prior to transfusion. This peculiarity requires blood services to store platelets at room temperature, limiting platelet supplies for clinical needs. Here, we describe the mechanism of this clearance system, a longstanding mystery. Chilling platelets clusters their von Willebrand (vWf) receptors, eliciting recognition of mouse and human platelets by hepatic macrophage complement type 3 (CR3) receptors. CR3-expressing but not CR3-deficient mice exposed to cold rapidly decrease platelet counts. Cooling primes platelets for activation. We propose that platelets are thermosensors, primed at peripheral sites where most injuries occurred throughout evolution. Clearance prevents pathologic thrombosis by primed platelets. Chilled platelets bind vWf and function normally in vitro and ex vivo after transfusion into CR3-deficient mice. Therefore, GPIb modification might permit cold platelet storage.

  6. Overview of platelet physiology and laboratory evaluation of platelet function.

    PubMed

    Rodgers, G M

    1999-06-01

    Appropriate laboratory testing for the platelet-type bleeding disorders hinges on an adequate assessment in the history and physical examination. Patients with histories and screening laboratory results consistent with coagulation disorders (hemophilia, disseminated intravascular coagulation) are not appropriate candidates for platelet function testing. In contrast, patients with a lifelong history of platelet-type bleeding symptoms and perhaps a positive family history of bleeding would be appropriate for testing. Figure 6 depicts one strategy to evaluate these patients. Platelet morphology can easily be evaluated to screen for two uncommon qualitative platelet disorders: Bernard-Soulier syndrome (associated with giant platelets) and gray platelet syndrome, a subtype of storage pool disorder in which platelet granulation is morphologically abnormal by light microscopy. If the bleeding disorder occurred later in life (no bleeding with surgery or trauma early in life), the focus should be on acquired disorders of platelet function. For those patients thought to have an inherited disorder, testing for vWD should be done initially because approximately 1% of the population has vWD. The complete vWD panel (factor VIII coagulant activity, vWf antigen, ristocetin cofactor activity) should be performed because many patients will have abnormalities of only one particular panel component. Patients diagnosed with vWD should be classified using multimeric analysis to identify the type 1 vWD patients likely to respond to DDAVP. If vWD studies are normal, platelet aggregation testing should be performed, ensuring that no antiplatelet medications have been ingested at least 1 week before testing. If platelet aggregation tests are normal and if suspicion for an inherited disorder remains high, vWD testing should be repeated. The evaluation of thrombocytopenia may require bone marrow examination to exclude primary hematologic disorders. If future studies with thrombopoietin assays

  7. Platelet bioreactor-on-a-chip

    PubMed Central

    Mazutis, Linas; Wu, Stephen; Sylman, Joanna L.; Ehrlicher, Allen; Machlus, Kellie R.; Feng, Qiang; Lu, Shijiang; Lanza, Robert; Neeves, Keith B.; Weitz, David A.; Italiano, Joseph E.

    2014-01-01

    Platelet transfusions total >2.17 million apheresis-equivalent units per year in the United States and are derived entirely from human donors, despite clinically significant immunogenicity, associated risk of sepsis, and inventory shortages due to high demand and 5-day shelf life. To take advantage of known physiological drivers of thrombopoiesis, we have developed a microfluidic human platelet bioreactor that recapitulates bone marrow stiffness, extracellular matrix composition, micro-channel size, hemodynamic vascular shear stress, and endothelial cell contacts, and it supports high-resolution live-cell microscopy and quantification of platelet production. Physiological shear stresses triggered proplatelet initiation, reproduced ex vivo bone marrow proplatelet production, and generated functional platelets. Modeling human bone marrow composition and hemodynamics in vitro obviates risks associated with platelet procurement and storage to help meet growing transfusion needs. PMID:25606631

  8. Extended Storage of Pathogen-Reduced Platelet Concentrates (PRECON)

    DTIC Science & Technology

    2016-10-01

    J. Slichter, MD CONTRACTING ORGANIZATION: Bloodworks Northwest Seattle, WA 98104 REPORT DATE : October 2016 TYPE OF REPORT: Annual Report...NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE October 2016 2. REPORT TYPE Annual 3. DATES COVERED 26-SEP-15 to 25-SEP-16 4. TITLE AND...Platelet Concentrates (PRECON) dated 7/21/14 • Protocol - Cold Apheresis Platelets in Isoplate (CAPI) • Quad Chart 10 Date : 07-21-2014 Project Title

  9. pH value promotes growth of Staphylococcus epidermidis in platelet concentrates.

    PubMed

    Störmer, Melanie; Kleesiek, Knut; Dreier, Jens

    2008-05-01

    The platelet (PLT) storage lesion is characterized metabolically by a pH value associated with lactic acid generation. PLT storage conditions support the growth of Staphylococcus epidermidis, the most common organism implicated in bacterial contamination of PLT concentrates (PCs). Here, different factors that influence bacterial growth in PCs are discussed and the relation between pH values of PCs and citrate plasma (CP) is studied, with emphasis on bacterial proliferation. The PLT lesion with regard to pH decrease and lactic acid production was monitored during storage and correlated to bacterial proliferation properties. A total of 115 coagulase-negative staphylococci, especially S. epidermidis isolates, were characterized for their proliferation in different blood components (CP, buffy coat-derived, and apheresis PCs). Furthermore, the influence of donor-specific, product-specific, species-specific, and strain-specific factors on bacterial proliferation was investigated. PCs showed a lower pH value in comparison to plasma during storage. Bacterial proliferation in PCs and the failure to grow in CP were determined with all organisms tested. No correlation to donor-specific, species-specific, or strain-specific factors was observed. Lowering the pH of CP resulted in bacterial proliferation, whereas a pH increase in the PC unit inhibited the proliferation of S. epidermidis. With emphasis on bacterial proliferation, the significant difference between PC and CP is the presence of metabolizing PLTs. The pH values of stored PLTs, but not those of stored plasma, support the growth of S. epidermidis.

  10. Extended Storage of Pathogen Reduced Platelet Concentrates (PRECON)

    DTIC Science & Technology

    2015-10-01

    J. Slichter, MD CONTRACTING ORGANIZATION: Bloodworks Northwest Seattle, WA 98104 REPORT DATE : October 2015 TYPE OF REPORT: Annual PREPARED FOR...YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE October 2015 2. REPORT TYPE Annual 3. DATES COVERED 26 Sep 2014 - 25 Sep 2015 4. TITLE AND SUBTITLE...accomplishments to date . Brrr Study Our study of platelets stored as whole blood at 4°C demonstrated that end-over-end rotation is required to reduce platelet

  11. Omics markers of the red cell storage lesion and metabolic linkage

    PubMed Central

    D’Alessandro, Angelo; Nemkov, Travis; Reisz, Julie; Dzieciatkowska, Monika; Wither, Matthew J.; Hansen, Kirk C.

    2017-01-01

    The introduction of omics technologies in the field of Transfusion Medicine has significantly advanced our understanding of the red cell storage lesion. While the clinical relevance of such a lesion is still a matter of debate, quantitative and redox proteomics approaches, as well quantitative metabolic flux analysis and metabolic tracing experiments promise to revolutionise our understanding of the role of blood processing strategies, inform the design and testing of novel additives or technologies (such as pathogen reduction), and evaluate the clinical relevance of donor and recipient biological variability with respect to red cell storability and transfusion outcomes. By reviewing existing literature in this rapidly expanding research endeavour, we highlight for the first time a correlation between metabolic markers of the red cell storage age and protein markers of haemolysis. Finally, we introduce the concept of metabolic linkage, i.e. the appreciation of a network of highly correlated small molecule metabolites which results from biochemical constraints of erythrocyte metabolic enzyme activities. For the foreseeable future, red cell studies will advance Transfusion Medicine and haematology by addressing the alteration of metabolic linkage phenotypes in response to stimuli, including, but not limited to, storage additives, enzymopathies (e.g. glucose 6-phosphate dehydrogenase deficiency), hypoxia, sepsis or haemorrhage. PMID:28263171

  12. Blood platelets: computerized morphometry applied on optical images

    NASA Astrophysics Data System (ADS)

    Korobova, Farida V.; Ivanova, Tatyana V.; Gusev, Alexander A.; Shmarov, Dmitry A.; Kozinets, Gennady I.

    2000-11-01

    The new technology of computerized morphometric image analysis of platelets on blood smears was developed. In a basis of the device is included analysis of cytophotometric and morphometric parameters of platelets. Geometrical and optical parameters of platelets on 35 donors, platelet concentrates and 15 patients with haemorrhagic thrombocythaemia were investigated, average meanings for the area, diameter, its logarithms and optical density of platelets in norm were received. Distribution of the areas, diameters and optical densities of platelets of patients with haemorrhagic thrombocythaemia differed from those at the healthy people. After a course of treatment these meanings came nearer to normal. The important characteristics of platelets in platelet concentrates after three days of storage were in limits of normal meanings, but differed from those in whole blood platelets. Obtained data allow to enter the quantitative standards into investigation of platelets of the healthy people and at various alteration of thrombocytopoieses.

  13. Platelet-derived growth factor (PDGF) in neoplastic and non-neoplastic cystic lesions of the central nervous system and in the cerebrospinal fluid.

    PubMed Central

    Nistér, M.; Enblad, P.; Bäckström, G.; Söderman, T.; Persson, L.; Heldin, C. H.; Westermark, B.

    1994-01-01

    The aim of this study was to determine the concentration of PDGF in vivo in neoplastic and non-neoplastic brain lesions. Fluid from cystic lesions and cerebrospinal fluid was tested in a radioreceptor assay that detects all described PDGF isoforms. High concentration of PDGF were found in cyst fluids from several astrocytomas, one metastatic melanoma, one metastatic lung adenocarcinoma and one intracerebral abscess. The PDGF concentrations were several times higher than the levels known to be required for maximal PDGF effects on cells in vitro. PDGF could also be detected in some non-neoplastic lesions, especially one intracerebral abscess. The finding of high amounts of PDGF in neoplastic lesions strongly supports the possibility that PDGF can be a mediator of tumour and stromal cell growth and motility in vivo. Comparison of PDGF and beta-thromboglobulin concentrations in the same fluids strongly indicates that the PDGF protein is locally produced rather than a result of platelet activation and derangement of the blood-brain barrier. PMID:8180030

  14. Splenic release of platelets contributes to increased circulating platelet size and inflammation after myocardial infarction.

    PubMed

    Gao, Xiao-Ming; Moore, Xiao-Lei; Liu, Yang; Wang, Xin-Yu; Han, Li-Ping; Su, Yidan; Tsai, Alan; Xu, Qi; Zhang, Ming; Lambert, Gavin W; Kiriazis, Helen; Gao, Wei; Dart, Anthony M; Du, Xiao-Jun

    2016-07-01

    Acute myocardial infarction (AMI) is characterized by a rapid increase in circulating platelet size but the mechanism for this is unclear. Large platelets are hyperactive and associated with adverse clinical outcomes. We determined mean platelet volume (MPV) and platelet-monocyte conjugation (PMC) using blood samples from patients, and blood and the spleen from mice with AMI. We further measured changes in platelet size, PMC, cardiac and splenic contents of platelets and leucocyte infiltration into the mouse heart. In AMI patients, circulating MPV and PMC increased at 1-3 h post-MI and MPV returned to reference levels within 24 h after admission. In mice with MI, increases in platelet size and PMC became evident within 12 h and were sustained up to 72 h. Splenic platelets are bigger than circulating platelets in normal or infarct mice. At 24 h post-MI, splenic platelet storage was halved whereas cardiac platelets increased by 4-fold. Splenectomy attenuated all changes observed in the blood, reduced leucocyte and platelet accumulation in the infarct myocardium, limited infarct size and alleviated cardiac dilatation and dysfunction. AMI-induced elevated circulating levels of adenosine diphosphate and catecholamines in both human and the mouse, which may trigger splenic platelet release. Pharmacological inhibition of angiotensin-converting enzyme, β1-adrenergic receptor or platelet P2Y12 receptor reduced platelet abundance in the murine infarct myocardium albeit having diverse effects on platelet size and PMC. In conclusion, AMI evokes release of splenic platelets, which contributes to the increase in platelet size and PMC and facilitates myocardial accumulation of platelets and leucocytes, thereby promoting post-infarct inflammation. © 2016 The Author(s). published by Portland Press Limited on behalf of the Biochemical Society.

  15. Lipoprotein-associated phospholipase A(2), platelet-activating factor acetylhydrolase, is expressed by macrophages in human and rabbit atherosclerotic lesions.

    PubMed

    Häkkinen, T; Luoma, J S; Hiltunen, M O; Macphee, C H; Milliner, K J; Patel, L; Rice, S Q; Tew, D G; Karkola, K; Ylä-Herttuala, S

    1999-12-01

    We studied the expression of lipoprotein-associated phospholipase A(2) (Lp-PLA(2)), an enzyme capable of hydrolyzing platelet-activating factor (PAF), PAF-like phospholipids, and polar-modified phosphatidylcholines, in human and rabbit atherosclerotic lesions. Oxidative modification of low-density lipoprotein, which plays an important role in atherogenesis, generates biologically active PAF-like modified phospholipid derivatives with polar fatty acid chains. PAF is known to have a potent proinflammatory activity and is inactivated by its hydrolysis. On the other hand, lysophosphatidylcholine and oxidized fatty acids released from oxidized low-density lipoprotein as a result of Lp-PLA(2) activity are thought to be involved in the progression of atherosclerosis. Using combined in situ hybridization and immunocytochemistry, we detected Lp-PLA(2) mRNA and protein in macrophages in both human and rabbit atherosclerotic lesions. Reverse transcriptase-polymerase chain reaction analysis indicated an increased expression of Lp-PLA(2) mRNA in human atherosclerotic lesions. In addition, approximately 6-fold higher Lp-PLA(2) activity was detected in atherosclerotic aortas of Watanabe heritable hyperlipidemic rabbits compared with normal aortas from control rabbits. It is concluded that (1) macrophages in both human and rabbit atherosclerotic lesions express Lp-PLA(2), which could cleave any oxidatively modified phosphatidylcholine present in the lesion area, and (2) modulation of Lp-PLA(2) activity could lead to antiatherogenic effects in the vessel wall.

  16. Clinical effectiveness of combining platelet rich fibrin with alloplastic bone substitute for the management of combined endodontic periodontal lesion

    PubMed Central

    2014-01-01

    The term "endo-perio" lesion has been proposed to describe the destructive lesion resulting from inflammatory products found in varying degrees in both the periodontium and the pulpal tissues. In most of the cases, clinical symptoms disappear following successful endodontic therapy. However failure after conventional root canal treatment calls for surgical intervention. A 35 year old male patient with endo-perio lesion in right maxillary lateral incisor was treated with platelet rich fibrin (PRF) and alloplastic bone substitute after conventional endodontic therapy. At the end of 6 months there was gain in clinical attachment, increased radiographic bone fill and reduction in probing depth which was maintained till 18 month follow-up. Present case report aims to evaluate the efficacy of PRF and alloplastic bone substitute in the management of intrabony defect associated with endo-perio lesion in maxillary lateral incisor because the healing potential of PRF and bone graft has not been widely studied in endodontics. The use of PRF allows the clinician to optimize tissue remodelling, wound healing and angiogenesis by the local delivery of growth factors and proteins. The novel technique described here enables the clinician to be benefited from the full regenerative capacity of this autologous biologic material. PMID:24516830

  17. Clinical effectiveness of combining platelet rich fibrin with alloplastic bone substitute for the management of combined endodontic periodontal lesion.

    PubMed

    Goyal, Lata

    2014-02-01

    The term "endo-perio" lesion has been proposed to describe the destructive lesion resulting from inflammatory products found in varying degrees in both the periodontium and the pulpal tissues. In most of the cases, clinical symptoms disappear following successful endodontic therapy. However failure after conventional root canal treatment calls for surgical intervention. A 35 year old male patient with endo-perio lesion in right maxillary lateral incisor was treated with platelet rich fibrin (PRF) and alloplastic bone substitute after conventional endodontic therapy. At the end of 6 months there was gain in clinical attachment, increased radiographic bone fill and reduction in probing depth which was maintained till 18 month follow-up. Present case report aims to evaluate the efficacy of PRF and alloplastic bone substitute in the management of intrabony defect associated with endo-perio lesion in maxillary lateral incisor because the healing potential of PRF and bone graft has not been widely studied in endodontics. The use of PRF allows the clinician to optimize tissue remodelling, wound healing and angiogenesis by the local delivery of growth factors and proteins. The novel technique described here enables the clinician to be benefited from the full regenerative capacity of this autologous biologic material.

  18. Pathogen-Reduced, Extended Platelet Storage in Platelet Additive Solution (PAS)

    DTIC Science & Technology

    2016-10-01

    Sherrill J. Slichter, MD CONTRACTING ORGANIZATION: Bloodworks Northwest Seattle, WA 98104 REPORT DATE : October 2016 TYPE OF REPORT: Annual...PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE October 2016 2. REPORT TYPE Annual 3. DATES COVERED 15-SEP-15 to 14-SEP-16 4...the key research outcomes to date . Brrr Study Our study of platelets stored as whole blood at 4°C demonstrated that end-over-end rotation is required

  19. The origin and function of platelet glycosyltransferases

    PubMed Central

    Rumjantseva, Viktoria; Sørensen, Anne Louise Tølbøll; Patel-Hett, Sunita; Josefsson, Emma C.; Bennett, Eric P.; Italiano, Joseph E.; Clausen, Henrik; Hartwig, John H.; Hoffmeister, Karin M.

    2012-01-01

    Platelets are megakaryocyte subfragments that participate in hemostatic and host defense reactions and deliver pro- and antiangiogenic factors throughout the vascular system. Although they are anucleated cells that lack a complex secretory apparatus with distinct Golgi/endoplasmic reticulum compartments, past studies have shown that platelets have glycosyltransferase activities. In the present study, we show that members of 3 distinct glycosyltransferase families are found within and on the surface of platelets. Immunocytology and flow cytometry results indicated that megakaryocytes package these Golgi-derived glycosyltransferases into vesicles that are sent via proplatelets to nascent platelets, where they accumulate. These glycosyltransferases are active, and intact platelets glycosylate large exogenous substrates. Furthermore, we show that activation of platelets results in the release of soluble glycosyltransferase activities and that platelets contain sufficient levels of sugar nucleotides for detection of glycosylation of exogenously added substrates. Therefore, the results of the present study show that blood platelets are a rich source of both glycosyltransferases and donor sugar substrates that can be released to function in the extracellular space. This platelet-glycosylation machinery offers a pathway to a simple glycoengineering strategy improving storage of platelets and may serve hitherto unknown biologic functions. PMID:22613794

  20. Short-Term Storage of Platelet-Rich Plasma at Room Temperature Does Not Affect Growth Factor or Catabolic Cytokine Concentration.

    PubMed

    Wilson, Brooke H; Cole, Brian J; Goodale, Margaret B; Fortier, Lisa A

    2018-04-01

    The aim of this study was to provide clinical recommendations about the use of platelet-rich plasma (PRP) that was subjected to short-term storage at room temperature. We determined bioactive growth factor and cytokine concentrations as indicators of platelet and white blood cell degranulation in blood and PRP. Additionally, this study sought to validate the use of manual, direct smear analysis as an alternative to automated methods for platelet quantification in PRP. Blood was used to generate low-leukocyte PRP (Llo PRP) or high-leukocyte PRP (Lhi PRP). Blood was either processed immediately or kept at room temperature for 2 or 4 hours prior to generation of PRP, which was then held at room temperature for 0, 1, 2, or 4 hours. Subsequently, bioactive transforming growth factor beta-1 and matrix metalloproteinase-9 were measured by ELISA (enzyme-linked immunosorbent assay). Manual and automated platelet counts were performed on all blood and PRP samples. There were no differences in growth factor or cytokine concentration when blood or Llo PRP or Lhi PRP was retained at room temperature for up to 4 hours. Manual, direct smear analysis for platelet quantification was not different from the use of automated machine counting for PRP samples, but in the starting blood samples, manual platelet counts were significantly higher than those generated using automated technology. When there is a delay of up to 4 hours in the generation of PRP from blood or in the application of PRP to the patient, bioactive growth factor and cytokine concentrations remain stable in both blood and PRP. A manual direct counting method is a simple, cost-effective, and valid method to measure the contents of the PRP product being delivered to the patient.

  1. The behaviour of platelets in natural diamonds and the development of a new mantle thermometer

    NASA Astrophysics Data System (ADS)

    Speich, L.; Kohn, S. C.; Bulanova, G. P.; Smith, C. B.

    2018-05-01

    Platelets are one of the most common defects occurring in natural diamonds but their behaviour has not previously been well understood. Recent technical advances, and a much improved understanding of the correct interpretation of the main infrared (IR) feature associated with platelets (Speich et al. 2017), facilitated a systematic study of platelets in 40 natural diamonds. Three different types of platelet behaviour were identified here. Regular diamonds show linear correlations between both B-centre concentrations and platelet density and also between platelet size and platelet density. Irregular diamonds display reduced platelet density due to platelet breakdown, anomalously large or small platelets and a larger platelet size distribution. These features are indicative of high mantle storage temperatures. Finally, a previously unreported category of subregular diamonds is defined. These diamonds experienced low mantle residence temperatures and show smaller than expected platelets. Combining the systematic variation in platelet density with temperatures of mantle storage, determined by nitrogen aggregation, we can demonstrate that platelet degradation proceeds at a predictable rate. Thus, in platelet-bearing diamonds where N aggregation is complete, an estimate of annealing temperature can now be made for the first time.

  2. ( sup 3 H)Dopamine uptake by platelet storage granules in schizophrenia

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rabey, J.M.; Graff, E.; Oberman, Z.

    1992-01-01

    ({sup 3}H)Dopamine (DA) uptake by platelet storage granules was determined in 26 schizophrenic male patients, paranoid type (14 acute stage; 12 in remission) and 20 age-matched, normal controls. maximum velocity (Vmax) of DA uptake was significantly higher in acute patients, than patients in remission or controls (p>0.05). The apparent Michaelis constant (kM) of DA uptake in acute patients was also significantly different from chronic patients a substantial diminution of DA uptake, while haloperidol produced a substantial diminution of DA uptake, while haloperidol (10{sup {minus}4}, 10{sup {minus}5} M) did not affect the assay. Considering that a DA disequilibrium in schizophrenia maymore » be expressed not only in the brain, but also in the periphery and that an increased amount of DA accumulated in the vesicles, implies that an increased quantity of catecholamine is available for release, our findings suggest additional evidence for the role of DA overactivity in the pathophysiology of this disorder.« less

  3. Refrigerated storage of platelets initiates changes in platelet surface marker expression and localization of intracellular proteins.

    PubMed

    Wood, Ben; Padula, Matthew P; Marks, Denese C; Johnson, Lacey

    2016-10-01

    Platelets (PLTs) are currently stored at room temperature (22°C), which limits their shelf life, primarily due to the risk of bacterial growth. Alternatives to room temperature storage include PLT refrigeration (2-6°C), which inhibits bacterial growth, thus potentially allowing an extension of shelf life. Additionally, refrigerated PLTs appear more hemostatically active than conventional PLTs, which may be beneficial in certain clinical situations. However, the mechanisms responsible for this hemostatic function are not well characterized. The aim of this study was to assess the protein profile of refrigerated PLTs in an effort to understand these functional consequences. Buffy coat PLTs were pooled, split, and stored either at room temperature (20-24°C) or under refrigerated (2-6°C) conditions (n = 8 in each group). PLTs were assessed for changes in external receptor expression and actin filamentation using flow cytometry. Intracellular proteomic changes were assessed using two-dimensional gel electrophoresis and Western blotting. PLT refrigeration significantly reduced the abundance of glycoproteins (GPIb, GPIX, GPIIb, and GPIV) on the external membrane. However, refrigeration resulted in the increased expression of high-affinity integrins (αIIbβ3 and β1) and activation and apoptosis markers (CD62P, CD63, and phosphatidylserine). PLT refrigeration substantially altered the abundance and localization of several cytoskeletal proteins and resulted in an increase in actin filamentation, as measured by phalloidin staining. Refrigerated storage of PLTs induces significant changes in the expression and localization of both surface-expressed and intracellular proteins. Understanding these proteomic changes may help to identify the mechanisms resulting in the refrigeration-associated alterations in PLT function and clearance. © 2016 AABB.

  4. Progress in bio-manufacture of platelets for transfusion.

    PubMed

    Heazlewood, Shen Y; Nilsson, Susan K; Cartledge, Kellie; Be, Cheang Ly; Vinson, Andrew; Gel, Murat; Haylock, David N

    2017-11-01

    Blood transfusion services face an ever-increasing demand for donor platelets to meet clinical needs. Whilst strategies for increasing platelet storage life and improving the efficiency of donor platelet collection are important, in the longer term, platelets generated by bio-manufacturing processes will be required to meet demands. Production of sufficient numbers of in vitro-derived platelets for transfusion represents a significant bioengineering challenge. In this review, we highlight recent progress in this area of research and outline the main technical and biological obstacles that need to be met before this becomes feasible and economic. A critical consideration is assurance of the functional properties of these cells as compared to their fresh, donor collected, counterparts. We contend that platelet-like particles and in vitro-derived platelets that phenotypically resemble fresh platelets must deliver the same functions as these cells upon transfusion. We also note recent progress with immortalized megakaryocyte progenitor cell lines, molecular strategies for reducing expression of HLA Class I to generate universal donor platelets and the move to early clinical studies with in vitro-derived platelets.

  5. Quebec platelet disorder: features, pathogenesis and treatment.

    PubMed

    Diamandis, Maria; Veljkovic, D Kika; Maurer-Spurej, Elisabeth; Rivard, Georges E; Hayward, Catherine P M

    2008-03-01

    Quebec platelet disorder (QPD) is a rare, autosomal-dominant, inherited bleeding disorder that is associated with unique abnormalities in fibrinolysis. Its hallmark features are delayed-onset bleeding following hemostatic challenges that responds to fibrinolytic inhibitor therapy and increased expression and storage of the fibrinolytic enzyme urokinase plasminogen activator in platelets, without increased plasma urokinase plasminogen activator or systemic fibrinolysis. The increased urokinase plasminogen activator in QPD platelets is only partially inhibited, and, as a result, there is intraplatelet generation of plasmin, and secondary degradation of many platelet alpha-granule proteins. During clot formation, the urokinase plasminogen activator released by QPD platelets leads to platelet-dependent increased fibrinolysis, and this is postulated to be a major contributor to QPD bleeding. The focus of the present review is to summarize the current state of knowledge on QPD, including the history of this disorder, its clinical and laboratory features, and recommended approaches for its diagnosis and treatment.

  6. Platelets in blood stored in untreated and siliconed glass bottles and plastic bags

    PubMed Central

    Kissmeyer-Nielsen, F.; Madsen, C. B.; Nedergaard, Jytte

    1961-01-01

    Platelet survival was determined using untreated and siliconed glass bottles and plastic bags (Fenwal) for collecting and storing blood. The platelets were tagged in vivo with P32 in six polycythaemic patients undergoing treatment with P32. The results showed that fresh ACD blood collected in untreated glass, siliconed glass, and plastic gave the same recovery of platelets in the recipients. The use of EDTA (Fenwal formula) as anticoagulant gave results inferior to those obtained with blood using ACD as anticoagulant. Even after storage up to 24 hours in untreated glass bottles (ordinary bank blood) a satisfactory recovery of platelets was observed. After storage for 72 hours the recovery was less but not negligible. PMID:14456481

  7. Detection of microbial contamination in platelets

    NASA Astrophysics Data System (ADS)

    Berg, Tracy L.; Leparc, German; Huffman, Debra E.; Gennaccaro, Angela L.; Garcia-Lopez, Alicia; Klungness, Greta; Stephans, Christie; Garcia-Rubio, Luis H.

    2005-03-01

    In the United States, approximately 100 patients develop fatal sepsis associated with platelet transfusions every year. Current culture methods take 24-48 hours to acquire results, which in turn decrease the shelf life of platelets. Many of the microorganisms that contaminate platelets can replicate easily at room temperature, which is the necessary storage temperature to keep platelets functional. Therefore, there is a need for in-situ quality control assessment of the platelet quality. For this purpose, a real time spectrophotometric technique has been developed. The Spectral Acquisition Processing Detection (SAPD) method, comprised of a UV-vis spectrophotometer and modeling algorithms, is a rapid method that can be performed prior to platelet transfusion to decrease the risk of bacterial infection to patients. The SAPD method has been used to determine changes in cell suspensions, based on size, shape, chemical composition and internal structure. Changes in these cell characteristics can in turn be used to determine microbial contamination, platelet aging and other physiologic changes. Detection limits of this method for platelet suspensions seeded with bacterial contaminants were identified to be less than 100 cfu/ml of sample. Bacterial counts below 1000 cfu/ml are not considered clinically significant. The SAPD method can provide real-time identification of bacterial contamination of platelets affording patients an increased level of safety without causing undue strain on laboratory budgets or personnel while increasing the time frame that platelets can be used by dramatically shortening contaminant detection time.

  8. A novel second-generation polyolefin container for storage of single-donor apheresis platelets.

    PubMed

    Shimizu, T; Kouketsu, K; Kamiya, T; Futagawa, H; Hirose, S

    1989-01-01

    A non-blow-molded LE-2 polyolefin (PO) container was developed to store single-donor apheresis platelet concentrates (PCs) processed by the Haemonetics Plasma Collecting System (PCS) at 22 degrees C for over 1 day. We molded PO containers with heat-sealing of light-weight polymer alloy films with a thickness of 0.25 mm. The film was made of polymer blends consisting of polypropylene, styrene ethylene butylene styrene-block copolymer, and ethylene ethylacrylate copolymer. The PO container with enough strength and flexibility in routine practice has 2 and 1.6 times higher oxygen and carbon dioxide gas transfer properties than standard polyvinyl chloride (PVC) plastic containers. PCs (1-1.9 x 10(11) platelets) processed from 450 ml platelet-rich plasma were stored in 0.6-liter PO containers at 22 degrees C with flatbed agitation for up to 6 days. The pH of PCs was well maintained at the mean values of 7.0 in PO containers after 6 days in the well-oxygenated condition. The energy metabolism of stored platelets was determined. Oxygen consumption rates of platelets stored in PO containers averaged 1.5 nmol/min/10(9) platelets. The rates of glucose consumption and lactate production were 0.4 and 0.8 nmol/min/10(11) platelets, respectively. The rates of adenosine triphosphate (ATP) generation of platelets, 9.7 nmol/min/10(9) platelets, in PO containers did not differ from those in the PVC containers. Aggregation responses to adenosine diphosphate and hypotonic shock response of platelets were better maintained in PO containers. The morphological changes into sphere forms with projections and the appearance of unclassified forms were more frequently observed in PO than in PVC containers.(ABSTRACT TRUNCATED AT 250 WORDS)

  9. Platelet Dynamics during Natural and Pharmacologically Induced Torpor and Forced Hypothermia

    PubMed Central

    de Vrij, Edwin L.; Vogelaar, Pieter C.; Goris, Maaike; Houwertjes, Martin C.; Herwig, Annika; Dugbartey, George J.; Boerema, Ate S.; Strijkstra, Arjen M.; Bouma, Hjalmar R.; Henning, Robert H.

    2014-01-01

    Hibernation is an energy-conserving behavior in winter characterized by two phases: torpor and arousal. During torpor, markedly reduced metabolic activity results in inactivity and decreased body temperature. Arousal periods intersperse the torpor bouts and feature increased metabolism and euthermic body temperature. Alterations in physiological parameters, such as suppression of hemostasis, are thought to allow hibernators to survive periods of torpor and arousal without organ injury. While the state of torpor is potentially procoagulant, due to low blood flow, increased viscosity, immobility, hypoxia, and low body temperature, organ injury due to thromboembolism is absent. To investigate platelet dynamics during hibernation, we measured platelet count and function during and after natural torpor, pharmacologically induced torpor and forced hypothermia. Splenectomies were performed to unravel potential storage sites of platelets during torpor. Here we show that decreasing body temperature drives thrombocytopenia during torpor in hamster with maintained functionality of circulating platelets. Interestingly, hamster platelets during torpor do not express P-selectin, but expression is induced by treatment with ADP. Platelet count rapidly restores during arousal and rewarming. Platelet dynamics in hibernation are not affected by splenectomy before or during torpor. Reversible thrombocytopenia was also induced by forced hypothermia in both hibernating (hamster) and non-hibernating (rat and mouse) species without changing platelet function. Pharmacological torpor induced by injection of 5′-AMP in mice did not induce thrombocytopenia, possibly because 5′-AMP inhibits platelet function. The rapidness of changes in the numbers of circulating platelets, as well as marginal changes in immature platelet fractions upon arousal, strongly suggest that storage-and-release underlies the reversible thrombocytopenia during natural torpor. Possibly, margination of platelets

  10. Evaluation of Dried Storage of Platelets for Transfusion: Physiologic Integrity and Hemostatic Functionality

    DTIC Science & Technology

    1994-10-27

    paraformaidehyde in 500 mM Trehalose stored desiccated at RT, 4* C, or at -70,° C. Neither prep maintained good morphology at any temperature, and there...platelets, or para-platelets dried in Trehalose are as susceptible to loss of integrity over time as other preps. Our platelet handling techniques have

  11. Short term storage stability at room temperature of two different platelet-rich plasma preparations from equine donors and potential impact on growth factor concentrations.

    PubMed

    Hauschild, Gregor; Geburek, Florian; Gosheger, Georg; Eveslage, Maria; Serrano, Daniela; Streitbürger, Arne; Johannlükens, Sara; Menzel, Dirk; Mischke, Reinhard

    2017-01-05

    The increasing interest in platelet-rich plasma (PRP) based therapies is as yet accompanied by inconsistent information regarding nearly all aspects of handling and application. Among these storage stability of processed platelet-rich products may be the basis for a more flexible application mode. The objective of this study was (1) to estimate the storage stability of growth factors platelet derived growth factor BB (PDGF-BB) and transforming growth factor ß1 (TGF-ß1) in both, a single-step softspin centrifugation-based pure-PRP (P-PRP, ACP®), and a gravity filtration system-based leukocyte-rich-PRP (L-PRP, E-PET), over a six hours time span after preparation at room temperature and (2) to identify possible factors influencing these growth factor concentrations in an equine model. Growth factor concentrations remained stable over the entire investigation period in L-PRP as well as P-PRP preparations revealing a mean of 3569 pg/ml PDGF-BB for E-PET and means of 1276 pg/ml PDGF-BB and 5086 pg/ml TGF-ß1 for ACP®. Pearson correlations yielded no significant impact of whole blood platelet (PLT), white blood cell (WBC) and red blood cell (RBC) counts on resulting cytokine values. In case of ACP® no significant dependencies between PLT, WBC and RBC counts of the processed platelet-rich product and resulting cytokine content occurred with exception of TGF-ß1 concentrations showing a strong correlation with the WBC content. PDGF-BB content of E-PET preparations showed a strong positive correlation with PLT and a strong negative with WBC of these preparations but not with RBC. L-PRP ad modum E-PET and P-PRP ad modum ACP® are applicable over at least a six hours time span at room temperature without loss of growth factor content. Based on the results of this study factors influencing the resulting growth factor concentrations still remain questionable. Additional studies implicating a further standardization of preparation protocols are necessary to identify

  12. Electrospun silk fibroin fibers for storage and controlled release of human platelet lysate.

    PubMed

    Pignatelli, Cataldo; Perotto, Giovanni; Nardini, Marta; Cancedda, Ranieri; Mastrogiacomo, Maddalena; Athanassiou, Athanassia

    2018-04-17

    Human platelet lysate (hPL) is a pool of growth factors and cytokines able to induce regeneration of different tissues. Despite its good potentiality as therapeutic tool for regenerative medicine applications, hPL has been only moderately exploited in this field. A more widespread adoption has been limited because of its rapid degradation at room temperature that decreases its functionality. Another limiting factor for its extensive use is the difficulty of handling the hPL gels. In this work, silk fibroin-based patches were developed to address several points: improving the handling of hPL, enabling their delivery in a controlled manner and facilitating their storage by creating a device ready to use with expanded shelf life. Patches of fibroin loaded with hPL were synthesized by electrospinning to take advantage of the fibrous morphology. The release kinetics of the material was characterized and tuned through the control of fibroin crystallinity. Cell viability assays, performed with primary human dermal fibroblasts, demonstrated that fibroin is able to preserve the hPL biological activity and prolong its shelf-life. The strategy of storing and preserving small active molecules within a naturally-derived, protein-based fibrous scaffold was successfully implemented, leading to the design of a biocompatible device, which can potentially simplify the storage and the application of the hPL on a human patient, undergoing medical procedures such as surgery and wound care. Human platelets lysate (hPL) is a mixture of growth factors and cytokines able to induce the regeneration of damaged tissues. This study aims at enclosing hPL in a silk fibroin electrospun matrix to expand its utilization. Silk fibroin showed the ability to preserve the hPL activity at temperature up to 60 °C and the manipulation of fibroin's crystallinity provided a tool to modulate the hPL release kinetic. This entails the possibility to fabricate the hPL silk fibroin patches in advance and

  13. Platelet Vascular Endothelial Growth Factor is a Potential Mediator of Transfusion-Related Acute Lung Injury.

    PubMed

    Maloney, James P; Ambruso, Daniel R; Voelkel, Norbert F; Silliman, Christopher C

    The occurrence of non-hemolytic transfusion reactions is highest with platelet and plasma administration. Some of these reactions are characterized by endothelial leak, especially transfusion related acute lung injury (TRALI). Elevated concentrations of inflammatory mediators secreted by contaminating leukocytes during blood product storage may contribute to such reactions, but platelet-secreted mediators may also contribute. We hypothesized that platelet storage leads to accumulation of the endothelial permeability mediator vascular endothelial growth factor (VEGF), and that intravascular administration of exogenous VEGF leads to extensive binding to its lung receptors. Single donor, leukocyte-reduced apheresis platelet units were sampled over 5 days of storage. VEGF protein content of the centrifuged supernatant was determined by ELISA, and the potential contribution of VEGF from contaminating leukocytes was quantified. Isolated-perfused rat lungs were used to study the uptake of radiolabeled VEGF administered intravascularly, and the effect of unlabeled VEGF on lung leak. There was a time-dependent release of VEGF into the plasma fraction of the platelet concentrates (62 ± 9 pg/ml on day one, 149 ± 23 pg/ml on day 5; mean ± SEM, p<0.01, n=8) and a contribution by contaminating leukocytes was excluded. Exogenous 125I-VEGF bound avidly and specifically to the lung vasculature, and unlabeled VEGF in the lung perfusate caused vascular leak. Rising concentrations of VEGF occur during storage of single donor platelet concentrates due to platelet secretion or disintegration, but not due to leukocyte contamination. Exogenous VEGF at these concentrations rapidly binds to its receptors in the lung vessels. At higher VEGF concentrations, VEGF causes vascular leak in uninjured lungs. These data provide further evidence that VEGF may contribute to the increased lung permeability seen in TRALI associated with platelet products.

  14. Platelets and cancer: a casual or causal relationship: revisited

    PubMed Central

    Menter, David G.; Tucker, Stephanie C.; Kopetz, Scott; Sood, Anil K.; Crissman, John D.; Honn, Kenneth V.

    2014-01-01

    Human platelets arise as subcellular fragments of megakaryocytes in bone marrow. The physiologic demand, presence of disease such as cancer, or drug effects can regulate the production circulating platelets. Platelet biology is essential to hemostasis, vascular integrity, angiogenesis, inflammation, innate immunity, wound healing, and cancer biology. The most critical biological platelet response is serving as “First Responders” during the wounding process. The exposure of extracellular matrix proteins and intracellular components occurs after wounding. Numerous platelet receptors recognize matrix proteins that trigger platelet activation, adhesion, aggregation, and stabilization. Once activated, platelets change shape and degranulate to release growth factors and bioactive lipids into the blood stream. This cyclic process recruits and aggregates platelets along with thrombogenesis. This process facilitates wound closure or can recognize circulating pathologic bodies. Cancer cell entry into the blood stream triggers platelet-mediated recognition and is amplified by cell surface receptors, cellular products, extracellular factors, and immune cells. In some cases, these interactions suppress immune recognition and elimination of cancer cells or promote arrest at the endothelium, or entrapment in the microvasculature, and survival. This supports survival and spread of cancer cells and the establishment of secondary lesions to serve as important targets for prevention and therapy. PMID:24696047

  15. In vitro properties of concentrated canine platelets stored in two additive solutions: a comparative study.

    PubMed

    Hlavac, N; Lasta, C S; Dalmolin, M L; Lacerda, L A; de Korte, D; Marcondes, N A; Terra, S R; Fernandes, F B; González, F H D

    2017-11-15

    Platelet transfusion therapy poses many challenges in veterinary clinical practice. Lack of readily available blood donors, short shelf-life, and inability to administer a sufficient number of platelets to meet a dog's transfusion need are the major difficulties encountered. Platelet additive solutions are already in use at American and European human blood banks, showing to be a realistic alternative. This study compares the in vitro platelet function in plasma, Composol, or SSP+ during storage for 13 days. Platelet rich plasma-platelet concentrate with 35% plasma and 65% platelet additive solutions (Composol or SSP+) and a control group (100% plasma) were prepared. Swirling, platelet count, blood gases, metabolic variables, platelet activation markers, and apoptosis markers were analyzed on days 1, 5, 9 and 13. Swirling was well preserved and pH was acceptable (> 6.2) during storage for all platelet additive solutions units until day 9. SSP + units showed more stable pH and metabolic variables until day 13. Platelets in plasma showed higher glucose consumption than in Composol or in SSP+. The platelet additive solutions units showed better platelet metabolism maintenance, reduced glucose consumption and lactate production. The apoptotic markers were still low for 9 days in platelet concentrates with platelet additive solutions, suggesting the possibility to extend the shelf life with the use of SSP+ or Composol. Our findings suggest that the uses of Composol and SSP+ in canine platelet concentrates are potential alternatives in veterinary blood banks.

  16. Use of 8-methoxypsoralen and long-wavelength ultraviolet radiation for decontamination of platelet concentrates

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lin, L.; Wiesehahn, G.P.; Morel, P.A.

    1989-07-01

    Transmission of viral diseases through blood products remains an unsolved problem in transfusion medicine. We have developed a psoralen photochemical system for decontamination of platelet concentrates in which platelets are treated with long wavelength ultraviolet radiation (UVA, 320-400 nm) in the presence of 8-methoxypsoralen (8-MOP). Bacteria, RNA viruses, and DNA viruses ranging in genome size from 1.2 x 10(6) daltons, encompassing the size range of human pathogens, were inoculated into platelet concentrates and subjected to treatment. This system inactivated 25 to 30 logs/h of bacteria Escherichia coli or Staphylococcus aureus, 6 logs/h of bacteriophage fd, 0.9 log/h of bacteriophage R17more » and 1.1 logs/h of feline leukemia virus (FeLV) in platelet concentrates maintained in standard storage bags. Platelet integrity and in vitro function before, immediately following photochemical treatment, and during prolonged storage after treatment, were evaluated by measuring: (1) extracellular pH; (2) platelet yields; (3) extracellular lactate dehydrogenase (LDH) levels; (4) platelet morphology; (5) platelet aggregation responsiveness; (6) thromboxane beta-2 (TXB-2) production; (7) dense body secretion; and (8) alpha granule secretion. These assays demonstrated that this photochemical inactivation system inactivated bacteria and viruses in platelet concentrates with minimal adverse effects on the in vitro function of platelets in comparison to untreated control concentrates maintained under current, standard blood bank conditions.« less

  17. Dual roles for hepatic lectin receptors in the clearance of chilled platelets.

    PubMed

    Rumjantseva, Viktoria; Grewal, Prabhjit K; Wandall, Hans H; Josefsson, Emma C; Sørensen, Anne Louise; Larson, Göran; Marth, Jamey D; Hartwig, John H; Hoffmeister, Karin M

    2009-11-01

    Rapid chilling causes glycoprotein-Ib (GPIb) receptors to cluster on blood platelets. Hepatic macrophage beta(2) integrin binding to beta-N-acetylglucosamine (beta-GlcNAc) residues in the clusters leads to rapid clearance of acutely chilled platelets after transfusion. Although capping the beta-GlcNAc moieties by galactosylation prevents clearance of short-term-cooled platelets, this strategy is ineffective after prolonged refrigeration. We report here that prolonged refrigeration increased the density and concentration of exposed galactose residues on platelets such that hepatocytes, through Ashwell-Morell receptor binding, become increasingly involved in platelet removal. Macrophages rapidly removed a large fraction of transfused platelets independent of their storage conditions. With prolonged platelet chilling, hepatocyte-dependent clearance further diminishes platelet recovery and survival after transfusion. Inhibition of chilled platelet clearance by both beta(2) integrin and Ashwell-Morell receptors may afford a potentially simple method for storing platelets in the cold.

  18. Platelet Senescence and Phosphatidylserine Exposure

    PubMed Central

    Dasgupta, Swapan Kumar; Argaiz, Eduardo Rios; Chedid Mercado, Jose Emmanel; Elizondo Maul, Hector Omar; Garza, Jorge; Enriquez, Ana Bety; Abdel-Monem, Hanan; Prakasam, Anthony; Andreeff, Michael; Thiagarajan, Perumal

    2010-01-01

    Background The exposure of phosphatidylserine occurs during platelet activation and during in vitro storage. Phosphatidylserine exposure also occurs during apoptosis following the release of mitochondrial cytochrome c. We have examined the role of cytochrome c release, mitochondrial membrane potential (ΔΨm), and cyclophilin D (CypD) in phosphatidylserine exposure due to activation and storage. Study Design and Methods The exposure of phosphatidylserine and the loss ΔΨm were determined in a flow cytometer using FITC-lactadherin and JC-1, a lipophilic cationic reporter dye. The role of CypD was determined with cyclosporine A and CypD-deficient murine platelets. Cytochrome C induced caspase-3 and Rho associated kinase I (ROCK1) activation were determined by immunoblotting and using their inhibitors. Results Collagen and thrombin-induced exposure of phosphatidylserine was accompanied by a decrease in ΔΨm. Cyclosporin A inhibited the phosphatidylserine exposure and the loss of ΔΨm. CypD-/- mice had decreased loss of ΔΨm and impaired phosphatidylserine exposure. Collagen and thrombin did not induce the release of cytochrome c nor the activation of caspase-3 and ROCK1. In contrast, in platelets stored for more than 5 days, the phosphatidylserine exposure was associated with cytochrome c induced caspase-3 and ROCK1 activation. ABT737, a BH3 mimetic that induces mitochondrial pathway of apoptosis, induced cytochrome c release and activation of caspase-3 and ROCK1 and phosphatidylserine exposure independent of CypD. Conclusion These results show that in stored platelets cytochrome c release and the subsequent activation of caspase-3 and ROCK1 mediate phosphatidylserine exposure and it is distinct from activation-induced phosphatidylserine exposure. PMID:20456701

  19. In vitro platelet quality in storage containers used for pediatric transfusions.

    PubMed

    Weiss, Sandra; Scammell, Kenneth; Levin, Elena; Culibrk, Brankica; Zolfaghari, Sima; Gyöngyössy-Issa, Maria I C; Acker, Jason P

    2012-08-01

    The in vitro quality of small-volume platelet (PLT) aliquots for pediatric transfusions was assessed to determine the best practice approach. Small volumes (50 mL) of single apheresis PLT components (APCs), collected on either CaridianBCT Trima or Haemonetics MCS+ instruments, were aliquoted on Days 2, 3, 4, and 5 postcollection into Fenwal PL1240 or 4R2014 bags or 60-mL polypropylene syringes. Samples were tested for in vitro quality at their recommended expiry times (4 hr for 4R2014 bags and syringes or Day 5 for PL1240 bags). Assays included pH, CD62P expression, and metabolic measures. CD62P expression increased throughout storage in all containers. Among the small-volume containers, pH, pCO(2) , lactate, and bicarbonate varied considerably. Regardless of the day of aliquoting, pCO(2) was significantly higher and pO(2) was significantly lower in gas-impermeable syringes than other containers. No bacterial growth was detected in any sample. The quality of APCs aliquoted into small-volume containers meets regulatory requirements and is generally equivalent to that of full-volume APCs at expiry. © 2012 American Association of Blood Banks.

  20. Impact on storage quality of red blood cells and platelets by ultrahigh-frequency radiofrequency identification tags.

    PubMed

    Wang, Quan-Li; Wang, Xiao-Wei; Zhuo, Hai-Long; Shao, Chun-Yan; Wang, Jie; Wang, Hai-Ping

    2013-04-01

    Compared to ISBT128 code labels, radiofrequency identification (RFID) tags have incomparable advantages and gradually applied in blood management system. However, there is no global standard for the uses of RFID frequency. Even though ISBT recommended high-frequency RFID with 13.56MHz, 820- to 960-MHz ultrahigh frequency (UHF) RFID technology in many ways has even more advantages. For this reason, we studied the effect of UHF RFID tags with 820- to 960-MHz exposure on storage quality of red blood cells (RBCs) and platelets (PLTs). Thirty units of collected and prepared suspended RBCs (sRBCs) and PLTs were divided into two bags, one each for the test and control groups. The sRBCs were stored in 4±2°C refrigerator and the PLTs in a 22±2°C rocking box. The test groups were exposed to RF reader continuously during storage. Sampling at different time points and biologic changes were tested. As the extension of storage and the pH and chlorine levels in the supernatant of sRBCs were reduced, free hemoglobin, potassium, and sodium increased, but were not significant between test and control groups (p>0.05). During the storage period, the pH levels, PLT count, and PLT aggregation rate were decreased in both test and control groups, but were not significant (p>0.05). When exposed to 820- to 960-MHz RF, the biologic and biochemical indexes are not found to be exacerbated during 35 days of storage for sRBCs and 5 days for PLTs, respectively. © 2012 American Association of Blood Banks.

  1. Multiwavelength UV/visible spectroscopy for the quantitative investigation of platelet quality

    NASA Astrophysics Data System (ADS)

    Mattley, Yvette D.; Leparc, German F.; Potter, Robert L.; Garcia-Rubio, Luis H.

    1998-04-01

    The quality of platelets transfused is vital to the effectiveness of the transfusion. Freshly prepared, discoid platelets are the most effective treatment for preventing spontaneous hemorrhage or for stopping an abnormal bleeding event. Current methodology for the routine testing of platelet quality involves random pH testing of platelet rich plasma and visual inspection of platelet rich plasma for a swirling pattern indicative of the discoid shape of the cells. The drawback to these methods is that they do not provide a quantitative and objective assay for platelet functionality that can be used on each platelet unit prior to transfusion. As part of a larger project aimed at characterizing whole blood and blood components with multiwavelength UV/vis spectroscopy, isolated platelets and platelet in platelet rich plasma have been investigated. Models based on Mie theory have been developed which allow for the extraction of quantitative information on platelet size, number and quality from multi-wavelength UV/vis spectra. These models have been used to quantify changes in platelet rich plasma during storage. The overall goal of this work is to develop a simple, rapid quantitative assay for platelet quality that can be used prior to platelet transfusion to ensure the effectiveness of the treatment. As a result of this work, the optical properties for isolated platelets, platelet rich plasma and leukodepleted platelet rich plasma have been determined.

  2. High Fat Diet Induces Adhesion of Platelets to Endothelium in Two Models of Dyslipidemia

    PubMed Central

    Gonzalez, Jaime; Donoso, Wendy; Díaz, Natalia; Albornoz, María Eliana; Huilcaman, Ricardo; Morales, Erik

    2014-01-01

    Cardiovascular diseases (CVD) represent about 30% of all global deaths. It is currently accepted that, in the atherogenic process, platelets play an important role, contributing to endothelial activation and modulation of the inflammatory phenomenon, promoting the beginning and formation of lesions and their subsequent thrombotic complications. The objective of the present work was to study using immunohistochemistry, the presence of platelets, monocytes/macrophages, and cell adhesion molecules (CD61, CD163, and CD54), in two stages of the atheromatous process. CF-1 mice fed a fat diet were used to obtain early stages of atheromatous process, denominated early stage of atherosclerosis, and ApoE−/− mice fed a fat diet were used to observe advanced stages of atherosclerosis. The CF-1 mice model presented immunostaining on endothelial surface for all three markers studied; the advanced atherosclerosis model in ApoE−/− mice also presented granular immunostaining on lesion thickness, for the same markers. These results suggest that platelets participate in atheromatous process from early stages to advance d stages. High fat diet induces adhesion of platelets to endothelial cells in vivo. These findings support studying the participation of platelets in the formation of atheromatous plate. PMID:25328689

  3. High fat diet induces adhesion of platelets to endothelium in two models of dyslipidemia.

    PubMed

    Gonzalez, Jaime; Donoso, Wendy; Díaz, Natalia; Albornoz, María Eliana; Huilcaman, Ricardo; Morales, Erik; Moore-Carrasco, Rodrigo

    2014-01-01

    Cardiovascular diseases (CVD) represent about 30% of all global deaths. It is currently accepted that, in the atherogenic process, platelets play an important role, contributing to endothelial activation and modulation of the inflammatory phenomenon, promoting the beginning and formation of lesions and their subsequent thrombotic complications. The objective of the present work was to study using immunohistochemistry, the presence of platelets, monocytes/macrophages, and cell adhesion molecules (CD61, CD163, and CD54), in two stages of the atheromatous process. CF-1 mice fed a fat diet were used to obtain early stages of atheromatous process, denominated early stage of atherosclerosis, and ApoE(-/-) mice fed a fat diet were used to observe advanced stages of atherosclerosis. The CF-1 mice model presented immunostaining on endothelial surface for all three markers studied; the advanced atherosclerosis model in ApoE(-/-) mice also presented granular immunostaining on lesion thickness, for the same markers. These results suggest that platelets participate in atheromatous process from early stages to advance d stages. High fat diet induces adhesion of platelets to endothelial cells in vivo. These findings support studying the participation of platelets in the formation of atheromatous plate.

  4. Pharmacological modulation of platelet function in hypertension.

    PubMed

    Blann, Andrew D; Nadar, Sunil; Lip, Gregory Y H

    2003-07-01

    Platelets exert a considerable influence on human morbidity and mortality. The rationale for their study in hypertension follows the observation that the major consequences of hypertension are stroke and myocardial infarction. However, the etiology of these consequences in hypertension is, paradoxically, not hemorrhagic (as might be expected from the effects of high blood pressure), but occlusive, with thrombus being the culprit lesion. Mechanisms of platelet activation include high shear force, activation of the renin-angiotensin system, endothelial changes, and the presence of comorbidity, such as atrial fibrillation. The treatment of high blood pressure brings about a reversal of the changes seen in the cell. This could be in part due to the direct effect of the drug on the megakaryocyte and/or the platelets themselves, or it might simply be due to the reduction in blood pressure. Some drugs, such as calcium channel antagonists and angiotensin II receptor blockers, however, might have direct effects on platelet biochemistry other than reducing blood pressure. Finally, antiplatelet drugs are becoming an important part of the management of high-risk hypertensives, which aim to minimize vascular complications.

  5. Platelet-targeted gene therapy with human factor VIII establishes haemostasis in dogs with haemophilia A.

    PubMed

    Du, Lily M; Nurden, Paquita; Nurden, Alan T; Nichols, Timothy C; Bellinger, Dwight A; Jensen, Eric S; Haberichter, Sandra L; Merricks, Elizabeth; Raymer, Robin A; Fang, Juan; Koukouritaki, Sevasti B; Jacobi, Paula M; Hawkins, Troy B; Cornetta, Kenneth; Shi, Qizhen; Wilcox, David A

    2013-01-01

    It is essential to improve therapies for controlling excessive bleeding in patients with haemorrhagic disorders. As activated blood platelets mediate the primary response to vascular injury, we hypothesize that storage of coagulation Factor VIII within platelets may provide a locally inducible treatment to maintain haemostasis for haemophilia A. Here we show that haematopoietic stem cell gene therapy can prevent the occurrence of severe bleeding episodes in dogs with haemophilia A for at least 2.5 years after transplantation. We employ a clinically relevant strategy based on a lentiviral vector encoding the ITGA2B gene promoter, which drives platelet-specific expression of human FVIII permitting storage and release of FVIII from activated platelets. One animal receives a hybrid molecule of FVIII fused to the von Willebrand Factor propeptide-D2 domain that traffics FVIII more effectively into α-granules. The absence of inhibitory antibodies to platelet-derived FVIII indicates that this approach may have benefit in patients who reject FVIII replacement therapies. Thus, platelet FVIII may provide effective long-term control of bleeding in patients with haemophilia A.

  6. Platelet-targeted gene therapy with human factor VIII establishes haemostasis in dogs with haemophilia A

    PubMed Central

    Du, Lily M.; Nurden, Paquita; Nurden, Alan T.; Nichols, Timothy C.; Bellinger, Dwight A.; Jensen, Eric S.; Haberichter, Sandra L.; Merricks, Elizabeth; Raymer, Robin A.; Fang, Juan; Koukouritaki, Sevasti B.; Jacobi, Paula M.; Hawkins, Troy B.; Cornetta, Kenneth; Shi, Qizhen; Wilcox, David A.

    2013-01-01

    It is essential to improve therapies for controlling excessive bleeding in patients with haemorrhagic disorders. As activated blood platelets mediate the primary response to vascular injury, we hypothesize that storage of coagulation Factor VIII within platelets may provide a locally inducible treatment to maintain haemostasis for haemophilia A. Here we show that haematopoietic stem cell gene therapy can prevent the occurrence of severe bleeding episodes in dogs with haemophilia A for at least 2.5 years after transplantation. We employ a clinically relevant strategy based on a lentiviral vector encoding the ITGA2B gene promoter, which drives platelet-specific expression of human FVIII permitting storage and release of FVIII from activated platelets. One animal receives a hybrid molecule of FVIII fused to the von Willebrand Factor propeptide-D2 domain that traffics FVIII more effectively into α-granules. The absence of inhibitory antibodies to platelet-derived FVIII indicates that this approach may have benefit in patients who reject FVIII replacement therapies. Thus, platelet FVIII may provide effective long-term control of bleeding in patients with haemophilia A. PMID:24253479

  7. Quantitative investigation of red blood cell three-dimensional geometric and chemical changes in the storage lesion using digital holographic microscopy.

    PubMed

    Jaferzadeh, Keyvan; Moon, Inkyu

    2015-11-01

    Quantitative phase information obtained by digital holographic microscopy (DHM) can provide new insight into the functions and morphology of single red blood cells (RBCs). Since the functionality of a RBC is related to its three-dimensional (3-D) shape, quantitative 3-D geometric changes induced by storage time can help hematologists realize its optimal functionality period. We quantitatively investigate RBC 3-D geometric changes in the storage lesion using DHM. Our experimental results show that the substantial geometric transformation of the biconcave-shaped RBCs to the spherocyte occurs due to RBC storage lesion. This transformation leads to progressive loss of cell surface area, surface-to-volume ratio, and functionality of RBCs. Furthermore, our quantitative analysis shows that there are significant correlations between chemical and morphological properties of RBCs.

  8. Surfactants reduce platelet-bubble and platelet-platelet binding induced by in vitro air embolism.

    PubMed

    Eckmann, David M; Armstead, Stephen C; Mardini, Feras

    2005-12-01

    The effect of gas bubbles on platelet behavior is poorly characterized. The authors assessed platelet-bubble and platelet-platelet binding in platelet-rich plasma in the presence and absence of bubbles and three surface-active compounds. Platelet-rich plasma was prepared from blood drawn from 16 volunteers. Experimental groups were surfactant alone, sparging (microbubble embolization) alone, sparging with surfactant, and neither sparging nor surfactant. The surfactants were Pluronic F-127 (Molecular Probes, Eugene, OR), Perftoran (OJSC SPC Perftoran, Moscow, Russia), and Dow Corning Antifoam 1510US (Dow Corning, Midland, MI). Videomicroscopy images of specimens drawn through rectangular glass microcapillaries on an inverted microscope and Coulter counter measurements were used to assess platelet-bubble and platelet-platelet binding, respectively, in calcium-free and recalcified samples. Histamine-induced and adenosine diphosphate-induced platelet-platelet binding were measured in unsparged samples. Differences between groups were considered significant for P < 0.05 using analysis of variance and the Bonferroni correction. Sixty to 100 platelets adhered to bubbles in sparged, surfactant-free samples. With sparging and surfactant, few platelets adhered to bubbles. Numbers of platelet singlets and multimers not adherent to bubbles were different (P < 0.05) compared both with unsparged samples and sparged samples without surfactant. No significant platelet-platelet binding occurred in uncalcified, sparged samples, although 20-30 platelets adhered to bubbles. Without sparging, histamine and adenosine diphosphate provoked platelet-platelet binding with and without surfactants present. Sparging causes platelets to bind to air bubbles and each other. Surfactants added before sparging attenuate platelet-bubble and platelet-platelet binding. Surfactants may have a clinical role in attenuating gas embolism-induced platelet-bubble and platelet-platelet binding.

  9. Sphingosine 1-phosphate release from platelets during clot formation: close correlation between platelet count and serum sphingosine 1-phosphate concentration

    PubMed Central

    2013-01-01

    Background Sphingosine 1-phosphate (Sph-1-P), abundantly stored in platelets and released extracellularly upon activation, plays important roles as an extracellular mediator by interacting with specific cell surface receptors, especially in the area of vascular biology and immunology/hematology. Although the plasma Sph-1-P level is reportedly determined by red blood cells (RBCs), but not platelets, this may not be true in cases where the platelets have been substantially activated. Methods and results We measured the Sph-1-P and dihydrosphingosine 1-phosphate (DHSph-1-P) levels in serum samples (in which the platelets had been fully activated) from subjects with (n = 21) and without (n = 33) hematological disorders. We found that patients with essential thrombocythemia exhibited higher serum Sph-1-P and DHSph-1-P concentrations. The serum Sph-1-P concentration was closely correlated with the platelet count but was very weakly correlated with the RBC count. Similar results were obtained for DHSph-1-P. The serum Sph-1-P and DHSph-1-P levels were inversely correlated with the level of autotaxin (ATX), a lysophosphatidic acid-producing enzyme. A multiple regression analysis also revealed that the platelet count had the greatest explanatory impact on the serum Sph-1-P level. Conclusions Our present results showed close correlations between both the serum Sph-1-P and DHSph-1-P levels and the platelet count (but not the RBC count); these results suggest that high concentrations of these sphingoid base phosphates may be released from platelets and may mediate cross talk between platelet activation and the formation of atherosclerotic lesions. PMID:23418753

  10. Effects of delayed laboratory processing on platelet serotonin levels.

    PubMed

    Sanner, Jennifer E; Frazier, Lorraine; Udtha, Malini

    2013-01-01

    Despite the availability of established guidelines for measuring platelet serotonin, these guidelines may be difficult to follow in a hospital setting where time to processing may vary from sample to sample. The purpose of this study was to evaluate the effect of the time to processing of human blood samples on the stability of the enzyme-linked immunosorbent assay (ELISA) for the determination of platelet serotonin levels in human plasma. Human blood samples collected from a convenience sample of eight healthy volunteers were analyzed to determine platelet serotonin levels from plasma collected in ethylene diamine tetra acetic acid (EDTA) tubes and stored at 4°C for 3 hr, 5 hr, 8 hr, and 12 hr. Refrigeration storage at 4°C for 3 hr, 5 hr, 8 hr, and 12 hr altered the platelet serotonin measurement when compared to immediate processing. The bias for the samples stored at 4°C for 3 hr was 102.3 (±217.39 ng/10(9) platelets), for 5 hr was 200.1 (±132.76 ng/10(9) platelets), for 8 hr was 146.9 (±221.41 ng/10(9) platelets), and for 12 hr was -67.6 (±349.60 ng/10(9) platelets). Results from this study show that accurate measurement of platelet serotonin levels is dependent on time to processing. Researchers should therefore follow a standardized laboratory guideline for obtaining immediate platelet serotonin levels after blood sample collection.

  11. Platelet “First Responders” in Wound Response, Cancer, and Metastasis

    PubMed Central

    Menter, David G.; Kopetz, Scott; Hawk, Ernest; Sood, Anil K.; Loree, Jonathan M; Gresele, Paolo; Honn, Kenneth V.

    2017-01-01

    Platelets serve as “First Responders” during normal wounding and homeostasis. Arising from bone marrow stem cell lineage megakaryocytes, anucleate platelets can influence inflammation and immune regulation. Biophysically, platelets are optimized due to size and discoid morphology to distribute near vessel walls, monitor vascular integrity and initiate quick responses to vascular lesions. Adhesion receptors linked to a highly reactive filopodia-generating cytoskeleton maximizes their vascular surface contact allowing rapid response capabilities. Functionally, platelets normally initiate rapid clotting, vasoconstriction, inflammation and wound biology that leads to sterilization, tissue repair and resolution. Platelets also are among the first to sense, phagocytize, decorate, or react to pathogens in the circulation. These platelet first responder properties are commandeered during chronic inflammation, cancer progression and metastasis. Leaky or inflammatory reaction blood vessel genesis during carcinogenesis provides opportunities for platelet invasion into tumors. Cancer is thought of as a non-healing or chronic wound that can be actively aided by platelet mitogenic properties to stimulate tumor growth. This growth ultimately outstrips circulatory support leads to angiogenesis and intravasation of tumor cells into the blood stream. Circulating tumor cells reengage additional platelets, which facilitates tumor cell adhesion, arrest and extravasation and metastasis. This process, along with the hypercoagulable states associated with malignancy is amplified by IL6 production in tumors that stimulate liver thrombopoietin production and elevates circulating platelet numbers by thrombopoiesis in the bone marrow. These complex interactions and the “First Responder” role of platelets during diverse physiologic stresses provides a useful therapeutic target that deserves further exploration. PMID:28730545

  12. Blood platelet kinetics and platelet transfusion.

    PubMed

    Aster, Richard H

    2013-11-01

    The discovery of citrate anticoagulant in the 1920s and the development of plastic packs for blood collection in the 1960s laid the groundwork for platelet transfusion therapy on a scale not previously possible. A major limitation, however, was the finding that platelet concentrates prepared from blood anticoagulated with citrate were unsuitable for transfusion because of platelet clumping. We found that this could be prevented by simply reducing the pH of platelet-rich plasma to about 6.5 prior to centrifugation. We used this approach to characterize platelet kinetics and sites of platelet sequestration in normal and pathologic states and to define the influence of variables such as anticoagulant and ABO incompatibility on post-transfusion platelet recovery. The "acidification" approach enabled much wider use of platelet transfusion therapy until alternative means of producing concentrates suitable for transfusion became available.

  13. Extended Storage of Pathogen-Reduced Platelet Concentrates (PRECON)

    DTIC Science & Technology

    2017-12-01

    J. Slichter, MD CONTRACTING ORGANIZATION: Bloodworks Northwest Seattle, WA 98104 REPORT DATE : December 2017 TYPE OF REPORT: Final PREPARED FOR...YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE December 2017 2. REPORT TYPE Final 3. DATES COVERED 26-SEP-13 to 25-SEP-17 4. TITLE AND SUBTITLE...comparator. Both the stored and the fresh platelets 4 were administered simultaneously using two different radioisotopes ( ≤15 μCi of indium for the

  14. Composition of growth factors and cytokines in lysates obtained from fresh versus stored pathogen-inactivated platelet units.

    PubMed

    Sellberg, Felix; Berglund, Erik; Ronaghi, Martin; Strandberg, Gabriel; Löf, Helena; Sommar, Pehr; Lubenow, Norbert; Knutson, Folke; Berglund, David

    2016-12-01

    Platelet lysate is a readily available source of growth factors, and other mediators, which has been used in a variety of clinical applications. However, the product remains poorly standardized and the present investigation evaluates the composition of platelet lysate obtained from either fresh or stored pathogen-inactivated platelet units. Platelet pooled units (n = 10) were obtained from healthy blood donors and tested according to standard procedures. All units were pathogen inactivated using amotosalen hydrochloride and UVA exposure. Platelet lysate was subsequently produced at two separate time-points, either from fresh platelet units or after 5 days of storage, by repeated freeze-thaw cycles. The following mediators were determined at each time-point: EGF, FGF-2, VEGF, IGF-1, PDGF-AB/BB, BMP-2, PF4, TGF-β isoform 1, IL-1β, IL-2, IL-6, IL-10, IL-12p70, 1L-17A, TNF-α, and IFN-γ. The concentration of growth factors and cytokines was affected by time in storage. Notably, TGF-β, PDGF-AB/BB, and PF4 showed an increase of 27.2% (p < 0.0001), 29.5% (p = 0.04) and 8.2% (p = 0.0004), respectively. A decrease was seen in the levels of IGF-1 and FGF-2 with 22% (p = 0.041) and 11% (p = 0.01), respectively. Cytokines were present only in very low concentrations and all other growth factors remained stable with time in storage. The composition of mediators in platelet lysate obtained from pathogen-inactivated platelet units differs when produced from fresh and stored platelet units, respectively. This underscores the need for further standardization and optimization of this important product, which potentially may influence the clinical effects. Copyright © 2016. Published by Elsevier Ltd.

  15. Cholesterol efflux in megakaryocyte progenitors suppresses platelet production and thrombocytosis

    PubMed Central

    Murphy, Andrew J.; Bijl, Nora; Yvan-Charvet, Laurent; Welch, Carrie B.; Bhagwat, Neha; Reheman, Adili; Wang, Yiming; Shaw, James A.; Levine, Ross L.; Ni, Heyu; Tall, Alan R.; Wang, Nan

    2013-01-01

    Platelets play a key role in atherogenesis and its complications. Both hypercholesterolemia and increased platelet production promote athero-thrombosis; however, a potential link between altered cholesterol homeostasis and platelet production has not been explored. Transplantation of bone marrow (BM) deficient in ABCG4, a transporter of unknown function, into Ldlr−/− mice resulted in thrombocytosis, accelerated thrombosis and atherosclerosis. While not detected in lesions, Abcg4 was highly expressed in BM megakaryocyte progenitors (MkP). Abcg4−/− MkPs displayed defective cholesterol efflux to HDL, increased cell surface levels of thrombopoietin (TPO) receptor (c-MPL) and enhanced proliferation. This appeared to reflect disruption of the negative feedback regulation of c-MPL levels and signaling by E3 ligase c-CBL and cholesterol-sensing LYN kinase. HDL infusions reduced platelet counts in Ldlr−/− mice and in a mouse model of myeloproliferative neoplasm, in a completely ABCG4-dependent fashion. HDL infusions may offer a novel approach to reducing athero-thrombotic events associated with increased platelet production. PMID:23584088

  16. Evaluation of Dried Storage of Platelets and RBC for Transfusion: Lyophilization and Other Dehydration Techniques

    DTIC Science & Technology

    1991-01-31

    that a short incubation of platelets with 0.1% (final conc.) KMnO4 seems optimal, but a protective agent such as trehalose , sucrose, or albumin must...yields were improved also by inclusion of albumin during platelet washing and trehalose during the lyophilization step (74% recovery under best... trehalose is advantageous in this protocol has yet to be decided. Vesiculation of platelet membranes is still evident by flow cytometry in the

  17. Effects of plasma nitric oxide levels on platelet activation in single donor apheresis and random donor concentrates.

    PubMed

    Büyükkağnici, Demet Iren; Ilhan, Osman; Kavas, Güzin Ozelçi; Arslan, Onder; Arat, Mutlu; Dalva, Klara; Ayyildiz, Erol

    2007-02-01

    P-selectin is an useful marker to determine platelet activation and nitric oxide inhibits platelet activation, secretion, adhesion and aggregation. The aim of this study was to investigate the relationship between nitric oxide and P-selectin values in both single donor apheresis and random donor platelet concentrates. According to the results of this study, we found that the best platelet concentrate is freshly prepared single donor apheresis concentrate and it is important to prevent activation at the beginning of the donation. Nitric oxide, which is synthesized from platelets during the storage period, is not sufficient to prevent platelet activation.

  18. Hemoglobin-driven pathophysiology is an in vivo consequence of the red blood cell storage lesion that can be attenuated in guinea pigs by haptoglobin therapy.

    PubMed

    Baek, Jin Hyen; D'Agnillo, Felice; Vallelian, Florence; Pereira, Claudia P; Williams, Matthew C; Jia, Yiping; Schaer, Dominik J; Buehler, Paul W

    2012-04-01

    Massive transfusion of blood can lead to clinical complications, including multiorgan dysfunction and even death. Such severe clinical outcomes have been associated with longer red blood cell (rbc) storage times. Collectively referred to as the rbc storage lesion, rbc storage results in multiple biochemical changes that impact intracellular processes as well as membrane and cytoskeletal properties, resulting in cellular injury in vitro. However, how the rbc storage lesion triggers pathophysiology in vivo remains poorly defined. In this study, we developed a guinea pig transfusion model with blood stored under standard blood banking conditions for 2 (new), 21 (intermediate), or 28 days (old blood). Transfusion with old but not new blood led to intravascular hemolysis, acute hypertension, vascular injury, and kidney dysfunction associated with pathophysiology driven by hemoglobin (Hb). These adverse effects were dramatically attenuated when the high-affinity Hb scavenger haptoglobin (Hp) was administered at the time of transfusion with old blood. Pathologies observed after transfusion with old blood, together with the favorable response to Hp supplementation, allowed us to define the in vivo consequences of the rbc storage lesion as storage-related posttransfusion hemolysis producing Hb-driven pathophysiology. Hb sequestration by Hp might therefore be a therapeutic modality for enhancing transfusion safety in severely ill or massively transfused patients.

  19. Desialylation accelerates platelet clearance after refrigeration and initiates GPIbα metalloproteinase-mediated cleavage in mice.

    PubMed

    Jansen, A J Gerard; Josefsson, Emma C; Rumjantseva, Viktoria; Liu, Qiyong Peter; Falet, Hervé; Bergmeier, Wolfgang; Cifuni, Stephen M; Sackstein, Robert; von Andrian, Ulrich H; Wagner, Denisa D; Hartwig, John H; Hoffmeister, Karin M

    2012-02-02

    When refrigerated platelets are rewarmed, they secrete active sialidases, including the lysosomal sialidase Neu1, and express surface Neu3 that remove sialic acid from platelet von Willebrand factor receptor (VWFR), specifically the GPIbα subunit. The recovery and circulation of refrigerated platelets is greatly improved by storage in the presence of inhibitors of sialidases. Desialylated VWFR is also a target for metalloproteinases (MPs), because GPIbα and GPV are cleaved from the surface of refrigerated platelets. Receptor shedding is inhibited by the MP inhibitor GM6001 and does not occur in Adam17(ΔZn/ΔZn) platelets expressing inactive ADAM17. Critically, desialylation in the absence of MP-mediated receptor shedding is sufficient to cause the rapid clearance of platelets from circulation. Desialylation of platelet VWFR therefore triggers platelet clearance and primes GPIbα and GPV for MP-dependent cleavage.

  20. Arf6 controls platelet spreading and clot retraction via integrin αIIbβ3 trafficking

    PubMed Central

    Huang, Yunjie; Joshi, Smita; Xiang, Binggang; Kanaho, Yasunori; Li, Zhenyu; Bouchard, Beth A.; Moncman, Carole L.

    2016-01-01

    Platelet and megakaryocyte endocytosis is important for loading certain granule cargo (ie, fibrinogen [Fg] and vascular endothelial growth factor); however, the mechanisms of platelet endocytosis and its functional acute effects are understudied. Adenosine 5'-diphosphate–ribosylation factor 6 (Arf6) is a small guanosine triphosphate–binding protein that regulates endocytic trafficking, especially of integrins. To study platelet endocytosis, we generated platelet-specific Arf6 knockout (KO) mice. Arf6 KO platelets had less associated Fg suggesting that Arf6 affects αIIbβ3-mediated Fg uptake and/or storage. Other cargo was unaffected. To measure Fg uptake, mice were injected with biotinylated- or fluorescein isothiocyanate (FITC)–labeled Fg. Platelets from the injected Arf6 KO mice showed lower accumulation of tagged Fg, suggesting an uptake defect. Ex vivo, Arf6 KO platelets were also defective in FITC-Fg uptake and storage. Immunofluorescence analysis showed initial trafficking of FITC-Fg to a Rab4-positive compartment followed by colocalization with Rab11-positive structures, suggesting that platelets contain and use both early and recycling endosomes. Resting and activated αIIbβ3 levels, as measured by flow cytometry, were unchanged; yet, Arf6 KO platelets exhibited enhanced spreading on Fg and faster clot retraction. This was not the result of alterations in αIIbβ3 signaling, because myosin light-chain phosphorylation and Rac1/RhoA activation were unaffected. Consistent with the enhanced clot retraction and spreading, Arf6 KO mice showed no deficits in tail bleeding or FeCl3-induced carotid injury assays. Our studies present the first mouse model for defining the functions of platelet endocytosis and suggest that altered integrin trafficking may affect the efficacy of platelet function. PMID:26738539

  1. Arf6 controls platelet spreading and clot retraction via integrin αIIbβ3 trafficking.

    PubMed

    Huang, Yunjie; Joshi, Smita; Xiang, Binggang; Kanaho, Yasunori; Li, Zhenyu; Bouchard, Beth A; Moncman, Carole L; Whiteheart, Sidney W

    2016-03-17

    Platelet and megakaryocyte endocytosis is important for loading certain granule cargo (ie, fibrinogen [Fg] and vascular endothelial growth factor); however, the mechanisms of platelet endocytosis and its functional acute effects are understudied. Adenosine 5'-diphosphate-ribosylation factor 6 (Arf6) is a small guanosine triphosphate-binding protein that regulates endocytic trafficking, especially of integrins. To study platelet endocytosis, we generated platelet-specific Arf6 knockout (KO) mice. Arf6 KO platelets had less associated Fg suggesting that Arf6 affects αIIbβ3-mediated Fg uptake and/or storage. Other cargo was unaffected. To measure Fg uptake, mice were injected with biotinylated- or fluorescein isothiocyanate (FITC)-labeled Fg. Platelets from the injected Arf6 KO mice showed lower accumulation of tagged Fg, suggesting an uptake defect. Ex vivo, Arf6 KO platelets were also defective in FITC-Fg uptake and storage. Immunofluorescence analysis showed initial trafficking of FITC-Fg to a Rab4-positive compartment followed by colocalization with Rab11-positive structures, suggesting that platelets contain and use both early and recycling endosomes. Resting and activated αIIbβ3 levels, as measured by flow cytometry, were unchanged; yet, Arf6 KO platelets exhibited enhanced spreading on Fg and faster clot retraction. This was not the result of alterations in αIIbβ3 signaling, because myosin light-chain phosphorylation and Rac1/RhoA activation were unaffected. Consistent with the enhanced clot retraction and spreading, Arf6 KO mice showed no deficits in tail bleeding or FeCl3-induced carotid injury assays. Our studies present the first mouse model for defining the functions of platelet endocytosis and suggest that altered integrin trafficking may affect the efficacy of platelet function. © 2016 by The American Society of Hematology.

  2. Dietary calcium attenuates platelet aggregation and intracellular Ca2+ mobilization in spontaneously hypertensive rats

    NASA Technical Reports Server (NTRS)

    Otsuka, K.; Watanabe, M.; Yue, Q.; McCarron, D. A.; Hatton, D.

    1997-01-01

    Spontaneously hypertensive rats (SHR) are known to be blood pressure sensitive to dietary calcium. The effects of dietary calcium on platelet aggregation and intracellular Ca2+ mobilization were assessed by turbidimetric methods and fura-2 methods, respectively, in washed platelets of SHR. Ca2+ ATPase activity was examined in aortic membrane fractions. Six weeks of dietary calcium supplementation attenuated the increase of systolic blood pressure (SBP 199 +/- 16 v 170 +/- 9 mm Hg, P < .001) and thrombin-induced platelet aggregation (84.5 +/- 3.7 v 73.7 +/- 7.4%, P < .004) at 9 weeks of age. The ionomycin-induced intracellular calcium ([Ca2+]i) peak in the absence of external Ca2+, which reflects [Ca2+]i storage size, and thrombin-evoked [Ca2+]i release from [Ca2+]i storage were decreased by 2.0% Ca diet (472 +/- 55 v 370 +/- 23 nmol/L, P < .001, 339 +/- 29 v 278 +/- 33 nmol/L, P < .002). In addition, SBP was positively correlated with platelet aggregation (r = 0.703, P = .0088), thrombin-evoked [Ca2+]i (r = 0.739, P = .0044), and ionomycin-induced [Ca2+]i (r = 0.591, P = .0415), respectively. However, there was no significant effect of dietary calcium on Ca2+-ATPase activity in aortic membranes. These results suggest that dietary calcium supplementation had a beneficial effect on platelets of SHR by attenuating [Ca2+]i mobilization from [Ca2+]i storage. The hypotensive effect of dietary calcium might be associated with attenuated [Ca2+]i mobilization in SHR.

  3. Platelets in thrombosis and hemostasis: old topic with new mechanisms.

    PubMed

    Wang, Yiming; Andrews, Marc; Yang, Yan; Lang, Sean; Jin, Joseph W; Cameron-Vendrig, Alison; Zhu, Guangheng; Reheman, Adili; Ni, Heyu

    2012-12-01

    Platelets are small anucleate cells generated from megakaryocytes in the bone marrow. After being released into the circulation, platelets play key roles in the surveillance of vascular injury, and can quickly adhere and aggregate at the site of injury, which are critical events for vascular repair and hemostasis. However, the same biological processes of platelet adhesion and aggregation may also cause thrombotic disorders. The formation of a platelet plug at sites of atherosclerotic lesion rupture is the most common mechanism leading to myocardial or cerebral infarction. Platelet-related deep vein thrombosis is also one of the leading causes of mortality worldwide. The contribution of several platelet receptors and their ligands has been highlighted in these processes. In platelet adhesion, particularly at high shear stress, GPIbα-von Willebrand factor (VWF) interaction may initiate this event, which is followed by GPVI signalling and firm platelet adhesion mediated by members of the integrin family, such as β3 (αIIbβ3) and β1 (α2β1, α5β1) integrins. In platelet aggregation, although GPIbα-VWF, P selectin-sulfatides, and other molecules, may be involved, the process is mainly mediated by β3 (αIIbβ3) integrin and its ligands, such as fibrinogen and VWF. It is intriguing that platelet adhesion and aggregation still occur in mice lacking both fibrinogen and VWF, suggesting that other unforeseen molecule(s) may also be important in these processes. Identification and characterization of these molecules will enrich our knowledge in the basic science of hemostasis and thrombosis, and may lead to the development of new therapies against bleeding disorders and thrombotic diseases.

  4. Microparticles variability in fresh frozen plasma: preparation protocol and storage time effects.

    PubMed

    Kriebardis, Anastasios G; Antonelou, Marianna H; Georgatzakou, Hara T; Tzounakas, Vassilis L; Stamoulis, Konstantinos E; Papassideri, Issidora S

    2016-05-01

    Extracellular vesicles or microparticles exhibiting procoagulant and thrombogenic activity may contribute to the haemostatic potential of fresh frozen plasma. Fresh frozen plasma was prepared from platelet-rich plasma at 20 °C (Group-1 donors) or directly from whole blood at 4 °C (Group-2 donors). Each unit was aseptically divided into three parts, stored frozen for specific periods of time, and analysed by flow cytometry for procoagulant activity immediately after thaw or following post-thaw storage for 24 h at 4 °C. Donors' haematologic, biochemical and life-style profiles as well as circulating microparticles were analysed in parallel. Circulating microparticles exhibited a considerable interdonor but not intergroup variation. Fresh frozen plasma units were enriched in microparticles compared to plasma in vivo. Duration of storage significantly affected platelet- and red cell-derived microparticles. Fresh frozen plasma prepared directly from whole blood contained more residual platelets and more platelet-derived microparticles compared to fresh frozen plasma prepared from platelet-rich plasma. Consequently, there was a statistically significant difference in total, platelet- and red cell-derived microparticles between the two preparation protocols over storage time in the freezer. Preservation of the thawed units for 24 h at 4 °C did not significantly alter microparticle accumulation. Microparticle accumulation and anti-oxidant capacity of fresh frozen plasma was positively or negatively correlated, respectively, with the level of circulating microparticles in individual donors. The preparation protocol and the duration of storage in the freezer, independently and in combination, influenced the accumulation of microparticles in fresh frozen plasma units. In contrast, storage of thawed units for 24 h at 4 °C had no significant effect on the concentration of microparticles.

  5. Desialylation accelerates platelet clearance after refrigeration and initiates GPIbα metalloproteinase-mediated cleavage in mice

    PubMed Central

    Jansen, A. J. Gerard; Josefsson, Emma C.; Rumjantseva, Viktoria; Liu, Qiyong Peter; Falet, Hervé; Bergmeier, Wolfgang; Cifuni, Stephen M.; Sackstein, Robert; von Andrian, Ulrich H.; Wagner, Denisa D.; Hartwig, John H.

    2012-01-01

    When refrigerated platelets are rewarmed, they secrete active sialidases, including the lysosomal sialidase Neu1, and express surface Neu3 that remove sialic acid from platelet von Willebrand factor receptor (VWFR), specifically the GPIbα subunit. The recovery and circulation of refrigerated platelets is greatly improved by storage in the presence of inhibitors of sialidases. Desialylated VWFR is also a target for metalloproteinases (MPs), because GPIbα and GPV are cleaved from the surface of refrigerated platelets. Receptor shedding is inhibited by the MP inhibitor GM6001 and does not occur in Adam17ΔZn/ΔZn platelets expressing inactive ADAM17. Critically, desialylation in the absence of MP-mediated receptor shedding is sufficient to cause the rapid clearance of platelets from circulation. Desialylation of platelet VWFR therefore triggers platelet clearance and primes GPIbα and GPV for MP-dependent cleavage. PMID:22101895

  6. Quantitative, functional, morphological and ultrastructural recovery of platelets as predictor for cryopreservation.

    PubMed

    Balint, Bela; Vucetić, Dusan; Trajković-Lakić, Zlatija; Petakov, Marijana; Bugarski, Diana; Brajusković, Goran; Taseski, Jovan

    2002-01-01

    Cryopreservation of platelets is of great interest, since it could extend the shelf life of therapeutic platelet concentrates and facilitate stockpiling and inventory control in blood banking. Despite the use of many cryopreservation procedures the optimal cryopreservation procedure is not defined yet. We have compared the cryopreservation of human platelets by various protocols employing controlled-rate and non-controlled-rate freezing procedures in combination with different concentrations of DMSO (6% and 10%) or 5% DMSO + 6% HES combination. After storage for 1 to 3 months, samples were thawed and analyzed. Measurements included cell recovery, platelet viability according to hypotonic shock response (HSR), platelet aggregation with ADP, morphological and ultrastructural properties of defrozen platelets. Our findings show that the application of our original procedure for controlled-rate freezing consisting of six cooling steps (cooling rate 1 degree C/min) with compensation of released heat of fusion (cooling rate 2 degrees C/min) has significantly influenced the quality of thawed platelets. At the same time, a concentration of 6% DMSO proved to be the most effective. In summary, cryopreservation of human platelets using controlled-rate freezing procedure in combination with lower (6%) DMSO concentration resulted in less damage from freezing and higher recovered function of platelets.

  7. Platelet proteome reveals novel pathways of platelet activation and platelet-mediated immunoregulation in dengue.

    PubMed

    Trugilho, Monique Ramos de Oliveira; Hottz, Eugenio Damaceno; Brunoro, Giselle Villa Flor; Teixeira-Ferreira, André; Carvalho, Paulo Costa; Salazar, Gustavo Adolfo; Zimmerman, Guy A; Bozza, Fernando A; Bozza, Patrícia T; Perales, Jonas

    2017-05-01

    Dengue is the most prevalent human arbovirus disease worldwide. Dengue virus (DENV) infection causes syndromes varying from self-limiting febrile illness to severe dengue. Although dengue pathophysiology is not completely understood, it is widely accepted that increased inflammation plays important roles in dengue pathogenesis. Platelets are blood cells classically known as effectors of hemostasis which have been increasingly recognized to have major immune and inflammatory activities. Nevertheless, the phenotype and effector functions of platelets in dengue pathogenesis are not completely understood. Here we used quantitative proteomics to investigate the protein content of platelets in clinical samples from patients with dengue compared to platelets from healthy donors. Our assays revealed a set of 252 differentially abundant proteins. In silico analyses associated these proteins with key molecular events including platelet activation and inflammatory responses, and with events not previously attributed to platelets during dengue infection including antigen processing and presentation, proteasome activity, and expression of histones. From these results, we conducted functional assays using samples from a larger cohort of patients and demonstrated evidence for platelet activation indicated by P-selectin (CD62P) translocation and secretion of granule-stored chemokines by platelets. In addition, we found evidence that DENV infection triggers HLA class I synthesis and surface expression by a mechanism depending on functional proteasome activity. Furthermore, we demonstrate that cell-free histone H2A released during dengue infection binds to platelets, increasing platelet activation. These findings are consistent with functional importance of HLA class I, proteasome subunits, and histones that we found exclusively in proteome analysis of platelets in samples from dengue patients. Our study provides the first in-depth characterization of the platelet proteome in dengue

  8. Platelet proteome reveals novel pathways of platelet activation and platelet-mediated immunoregulation in dengue

    PubMed Central

    Teixeira-Ferreira, André; Carvalho, Paulo Costa; Salazar, Gustavo Adolfo; Zimmerman, Guy A.; Perales, Jonas

    2017-01-01

    Dengue is the most prevalent human arbovirus disease worldwide. Dengue virus (DENV) infection causes syndromes varying from self-limiting febrile illness to severe dengue. Although dengue pathophysiology is not completely understood, it is widely accepted that increased inflammation plays important roles in dengue pathogenesis. Platelets are blood cells classically known as effectors of hemostasis which have been increasingly recognized to have major immune and inflammatory activities. Nevertheless, the phenotype and effector functions of platelets in dengue pathogenesis are not completely understood. Here we used quantitative proteomics to investigate the protein content of platelets in clinical samples from patients with dengue compared to platelets from healthy donors. Our assays revealed a set of 252 differentially abundant proteins. In silico analyses associated these proteins with key molecular events including platelet activation and inflammatory responses, and with events not previously attributed to platelets during dengue infection including antigen processing and presentation, proteasome activity, and expression of histones. From these results, we conducted functional assays using samples from a larger cohort of patients and demonstrated evidence for platelet activation indicated by P-selectin (CD62P) translocation and secretion of granule-stored chemokines by platelets. In addition, we found evidence that DENV infection triggers HLA class I synthesis and surface expression by a mechanism depending on functional proteasome activity. Furthermore, we demonstrate that cell-free histone H2A released during dengue infection binds to platelets, increasing platelet activation. These findings are consistent with functional importance of HLA class I, proteasome subunits, and histones that we found exclusively in proteome analysis of platelets in samples from dengue patients. Our study provides the first in-depth characterization of the platelet proteome in dengue

  9. Microparticles variability in fresh frozen plasma: preparation protocol and storage time effects

    PubMed Central

    Kriebardis, Anastasios G.; Antonelou, Marianna H.; Georgatzakou, Hara T.; Tzounakas, Vassilis L.; Stamoulis, Konstantinos E.; Papassideri, Issidora S.

    2016-01-01

    Background Extracellular vesicles or microparticles exhibiting procoagulant and thrombogenic activity may contribute to the haemostatic potential of fresh frozen plasma. Materials and methods Fresh frozen plasma was prepared from platelet-rich plasma at 20 °C (Group-1 donors) or directly from whole blood at 4 °C (Group-2 donors). Each unit was aseptically divided into three parts, stored frozen for specific periods of time, and analysed by flow cytometry for procoagulant activity immediately after thaw or following post-thaw storage for 24 h at 4 °C. Donors’ haematologic, biochemical and life-style profiles as well as circulating microparticles were analysed in parallel. Results Circulating microparticles exhibited a considerable interdonor but not intergroup variation. Fresh frozen plasma units were enriched in microparticles compared to plasma in vivo. Duration of storage significantly affected platelet- and red cell-derived microparticles. Fresh frozen plasma prepared directly from whole blood contained more residual platelets and more platelet-derived microparticles compared to fresh frozen plasma prepared from platelet-rich plasma. Consequently, there was a statistically significant difference in total, platelet- and red cell-derived microparticles between the two preparation protocols over storage time in the freezer. Preservation of the thawed units for 24 h at 4 °C did not significantly alter microparticle accumulation. Microparticle accumulation and anti-oxidant capacity of fresh frozen plasma was positively or negatively correlated, respectively, with the level of circulating microparticles in individual donors. Discussion The preparation protocol and the duration of storage in the freezer, independently and in combination, influenced the accumulation of microparticles in fresh frozen plasma units. In contrast, storage of thawed units for 24 h at 4 °C had no significant effect on the concentration of microparticles. PMID:27136430

  10. Effect of aspirin and ticlopidine on platelet deposition in carotid atherosclerosis: assessment by indium-111 platelet scintigraphy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Isaka, Y.; Kimura, K.; Etani, H.

    The antiplatelet effects of aspirin and ticlopidine were studied by a dual-tracer method, using indium-111 labeled platelets and technetium-99m human serum albumin, in a group of 12 patients with suspected ischemic cerebrovascular disease. The magnitude of platelet accumulation at the carotid bifurcation was expressed as the ratio of radioactivity of indium-111 platelets deposited on the vascular wall to those circulating in the blood-pool (PAI, platelet accumulation index), 48 hr after injection of labeled platelets. PAI values were measured before (baseline studies) and after the antithrombotic therapies (aspirin studies: 325 mg bid for 22.3 +/- 1.3 days, ticlopidine studies: 100 mgmore » tid for 21.8 +/- 2.1 days). At the baseline, the mean PAI value at 24 carotid bifurcations in the patient group was 15.7 +/- 15.3% (mean +/- S.D.) compared to -4.3 +/- 9.1 at 24 carotid bifurcations in 12 normal subjects (p less than 0.01). We defined the upper limit for a normal PAI (%) value to be +13.9, namely the mean PAI plus 2 SD for the carotid bifurcation in normal subjects and used this value for semiquantitative analysis. At the baseline, significant elevation of PAI (more than 13.9%; positive scintigram) was observed at 12 of 24 vessels, while 12 other regions were negative (less than 13.9%). In the lesions with positive scintigraphic results at the baseline, the mean PAI (%) value from the baseline, aspirin and ticlopidine studies was 29.5 +/- 7.0, 11.2 +/- 8.5 (p less than 0.01 versus baseline) and 21.4 +/- 21.3 (not significant from baseline), respectively.« less

  11. Bacterial growth kinetics in ACD-A apheresis platelets: comparison of plasma and PAS III storage.

    PubMed

    Dumont, Larry J; Wood, Tammara A; Housman, Molly; Herschel, Louise; Brantigan, Barbara; Heber, Cheryl; Houghton, Jaime

    2011-05-01

    Our objective was to determine the growth kinetics of bacteria in leukoreduced apheresis platelets (LR-AP) in a platelet (PLT) additive solution (PAS; InterSol, Fenwal, Inc.) compared to LR-AP stored in plasma. Hyperconcentrated, double-dose LR-AP were collected from healthy donors with a separator (AMICUS, Fenwal, Inc.). LR-AP were evenly divided, InterSol was added to half (65% InterSol:35% plasma [PAS]), and PLTs in autologous plasma were used for a paired control (PL). Bacteria were inoculated into each LR-AP PAS/PL pair (0.5-1.6 colony-forming units [CFUs]/mL), and bacterial growth was followed for up to 7 days. Time to the end of the lag phase, doubling times, maximum concentration (conc-max), and time to maximum concentration (time-max) were estimated. Streptococcus viridans did not grow to detectable levels in either PAS or PL units. The other bacteria had no significant overall difference in the conc-max (p = 0.47) or time-max (p = 0.7) between PL and PAS LR-AP; PL had a 0.14 hours faster doubling rate (p = 0.023); and PAS had a 4.7 hours shorter lag time (p = 0.016). We observed that five index organisms will grow in LR-AP stored in a 35%:65% ratio of plasma to InterSol where initial bacterial concentrations are 0.5 to 1.6 CFUs/mL. The more rapid initiation of log-phase growth for bacteria within a PAS storage environment resulted in a bacterial concentration up to 4 logs higher in the PAS units compared to the plasma units at 24 hours, but with no difference in the conc-max. This may present an early bacterial detection advantage for PAS-stored PLTs. © 2010 American Association of Blood Banks.

  12. Platelet-derived-growth-factor-induced signalling in human platelets: phosphoinositide-3-kinase-dependent inhibition of platelet activation.

    PubMed Central

    Selheim, F; Fukami, M H; Holmsen, H; Vassbotn, F S

    2000-01-01

    Human platelets release platelet-derived growth factor (PDGF) from alpha-granules during platelet activation. We have previously shown that platelets have PDGF alpha-receptors, a transmembrane tyrosine kinase that takes part in negative feedback regulation during platelet activation. Here we have described a study of PDGF-induced tyrosine phosphorylation of platelet substrates and phosphoinositide 3-kinase (PI-3K) activity in collagen-stimulated platelets. By immunoblotting with phosphotyrosine antibodies of collagen-activated platelets we found that PDGF increased the phosphorylation of several platelet substrates, e.g. pp140, pp120 and pp85. PDGF inhibited collagen-induced platelet activation in the presence of inhibitors of autocrine stimulation, thus blocking the pure collagen-induced signal transduction. PDGF enhanced the collagen-induced formation of PtdIns(3,4)P(2) and PtdIns(3,4,5)P(3) as measured by HPLC. Wortmannin and LY294002, two unrelated inhibitors of PI-3K, were used to investigate the role of PI-3K in PDGF-induced platelet signalling. Incubation of platelets with wortmannin and LY294002 blocked the formation of three phosphorylated inositides as well as the inhibitory effect of PDGF on collagen-induced platelet activation. We conclude that the inhibitory effect of PDGF on platelet activation is PI-3K dependent. This is the first demonstration of a negative regulatory function of 3-phosphorylated inositides in platelets. PMID:10947961

  13. Platelet-derived-growth-factor-induced signalling in human platelets: phosphoinositide-3-kinase-dependent inhibition of platelet activation.

    PubMed

    Selheim, F; Fukami, M H; Holmsen, H; Vassbotn, F S

    2000-09-01

    Human platelets release platelet-derived growth factor (PDGF) from alpha-granules during platelet activation. We have previously shown that platelets have PDGF alpha-receptors, a transmembrane tyrosine kinase that takes part in negative feedback regulation during platelet activation. Here we have described a study of PDGF-induced tyrosine phosphorylation of platelet substrates and phosphoinositide 3-kinase (PI-3K) activity in collagen-stimulated platelets. By immunoblotting with phosphotyrosine antibodies of collagen-activated platelets we found that PDGF increased the phosphorylation of several platelet substrates, e.g. pp140, pp120 and pp85. PDGF inhibited collagen-induced platelet activation in the presence of inhibitors of autocrine stimulation, thus blocking the pure collagen-induced signal transduction. PDGF enhanced the collagen-induced formation of PtdIns(3,4)P(2) and PtdIns(3,4,5)P(3) as measured by HPLC. Wortmannin and LY294002, two unrelated inhibitors of PI-3K, were used to investigate the role of PI-3K in PDGF-induced platelet signalling. Incubation of platelets with wortmannin and LY294002 blocked the formation of three phosphorylated inositides as well as the inhibitory effect of PDGF on collagen-induced platelet activation. We conclude that the inhibitory effect of PDGF on platelet activation is PI-3K dependent. This is the first demonstration of a negative regulatory function of 3-phosphorylated inositides in platelets.

  14. Platelet-derived growth factor inhibits platelet activation in heparinized whole blood.

    PubMed

    Selheim, F; Holmsen, H; Vassbotn, F S

    1999-08-15

    We previously have demonstrated that human platelets have functionally active platelet-derived growth factor alpha-receptors. Studies with gel-filtered platelets showed that an autocrine inhibition pathway is transduced through this tyrosine kinase receptor during platelet activation. The physiological significance of this inhibitory effect of platelet-derived growth factor on gel-filtered platelets activation is, however, not known. In the present study, we investigated whether platelet-derived growth factor inhibits platelet activation under more physiological conditions in heparinized whole blood, which represents a more physiological condition than gel-filtered platelets. Using flow cytometric assays, we demonstrate here that platelet-derived growth factor inhibits thrombin-, thrombin receptor agonist peptide SFLLRN-, and collagen-induced platelet aggregation and shedding of platelet-derived microparticles from the platelet plasma membrane during platelet aggregation in stirred heparinized whole blood. The inhibitory effect of platelet-derived growth factor was dose dependent. However, under nonaggregating conditions (no stirring), we could not demonstrate any significant effect of platelet-derived growth factor on thrombin- and thrombin receptor agonist peptide-induced platelet surface expression of P-selectin. Our results demonstrate that platelet-derived growth factor appears to be a true antithrombotic agent only under aggregating conditions in heparinized whole blood.

  15. Quebec platelet disorder: update on pathogenesis, diagnosis, and treatment.

    PubMed

    Blavignac, Jessica; Bunimov, Natalia; Rivard, Georges E; Hayward, Catherine P M

    2011-09-01

    Quebec platelet disorder (QPD) is an autosomal dominant bleeding disorder associated with reduced platelet counts and a unique gain-of-function defect in fibrinolysis due to increased expression and storage of urokinase plasminogen activator (uPA) by megakaryocytes. QPD increases risks for bleeding and its key clinical feature is delayed-onset bleeding, following surgery, dental procedures or trauma, which responds only to treatment with fibrinolytic inhibitors. The genetic cause of the disorder is a tandem duplication mutation of the uPA gene, PLAU, which upregulates uPA expression in megakaryocytes by an unknown mechanism. The increased platelet stores of uPA trigger plasmin-mediated degradation of QPD α-granule proteins. The gain-of-function defect in fibrinolysis is thought to be central to the pathogenesis of QPD bleeding as the activation of QPD platelets leads to release of uPA from α-granules and accelerated clot lysis. The purpose of this review is to summarize current knowledge on QPD pathogenesis and the recommended approaches to QPD diagnosis and treatment. Thieme Medical Publishers.

  16. The influence of platelets, plasma and red blood cells on functional haemostatic assays.

    PubMed

    Bochsen, Louise; Johansson, Pär I; Kristensen, Annemarie T; Daugaard, Gedske; Ostrowski, Sisse R

    2011-04-01

    Functional whole blood haemostatic assays are used increasingly to guide transfusion therapy and monitor medical treatment and are also applied for in-vitro evaluations of the haemostatic potential of stored platelets. We investigated how the cellular and plasmatic elements, both isolated and combined, influenced the two methodologically different assays, thrombelastography (TEG) and impedance aggregometry (Multiplate). Platelet-rich plasma (200 × 10/l) or pure plasma (0 platelets), with and without added red blood cells (RBCs), hematocrit 0, 0.15 or 0.29, were produced in vitro from platelet concentrates, fresh frozen plasma and stored RBC. Pure platelets were investigated by removing plasma components from platelet concentrates by diafiltration against the platelet storage solution Intersol. Plasma was readded by diafiltration against plasma in Intersol. Haemostatic function was evaluated by TEG and Multiplate. In the TEG, increasing amounts of RBC reduced clot strength and clot kinetics (α-angle), most markedly in plasma/RBC without platelets. In contrast, RBC in a platelet concentrate matrix enhanced Multiplate aggregation in response to weak agonists (ADP and arachidonic acid). Furthermore, removing plasma from platelet concentrates eliminated the TEG response and diminished the Multiplate aggregation response, but readding plasma to the pure platelet concentrates restored the response. Each of the elements in whole blood, plasma, platelets and RBC, affected the Multiplate and TEG results differently. The results emphasize that the concentrations of all cellular and plasmatic components in whole blood should be taken into account when interpreting results obtained by TEG and multiplate.

  17. Additive solutions differentially affect metabolic and functional parameters of platelet concentrates.

    PubMed

    Leitner, G C; List, J; Horvath, M; Eichelberger, B; Panzer, S; Jilma-Stohlawetz, P

    2016-01-01

    Pathogen inactivation (PI) of platelet concentrates with extension of shelf life to 7 days requires the use of platelet additive solutions (PAS). We examined the quality of platelets resuspended in three different PAS stored for up to 7 days. Twelve triple adult dose platelet concentrates (PC) were collected using the TrimaAccel® collection system. Each highly concentrated product was divided into three equal parts, and the additive solutions (Composol® or SSP+® or Intersol™) were added to a final concentration of 56% PAS and 44% plasma. Samples were drawn on days 1, 5 and 7 to measure pH, glucose, lactate dehydrogenase (LDH), lactate, mean platelet volume (MPV) and the aggregation response to collagen and the thrombin receptor agonist peptide-6. Further, p-selectin expression on platelets was assessed. No statistically significant changes were observed for pH and MPV during 7 days of storage in all PAS containing PCs, whereas glucose decreased and LDH and lactate increased over time (P < 0·05). These changes were particularly evident in Intersol PCs on days 5 and 7 compared with Composol® PCs or SSP+® PCs (P < 0·05). Platelets from Intersol PCs exhibited the highest baseline activation of p-selectin and showed reduced collagen- and TRAP-6-induced aggregation. Resuspension of platelets in Intersol for 7 days results in increased platelet activation and platelet metabolism compared with SSP+® or Composol®. Further clinical studies are needed to evaluate whether the observed differences in PAS-PCs affect the recovery rate or the life span of transfused platelets. © 2015 International Society of Blood Transfusion.

  18. FlnA-null megakaryocytes prematurely release large and fragile platelets that circulate poorly

    PubMed Central

    Jurak Begonja, Antonija; Hoffmeister, Karin M.; Hartwig, John H.

    2011-01-01

    Filamin A (FlnA) is a large cytoplasmic protein that crosslinks actin filaments and anchors membrane receptors and signaling intermediates. FlnAloxP PF4-Cre mice that lack FlnA in the megakaryocyte (MK) lineage have a severe macrothrombocytopenia because of accelerated platelet clearance. Macrophage ablation by injection of clodronate-encapsulated liposomes increases blood platelet counts in FlnAloxP PF4-Cre mice and reveals the desintegration of FlnA-null platelets into microvesicles, a process that occurs spontaneously during storage. FlnAloxP PF4-Cre bone marrows and spleens have a 2.5- to 5-fold increase in MK numbers, indicating increased thrombopoiesis in vivo. Analysis of platelet production in vitro reveals that FlnA-null MKs prematurely convert their cytoplasm into large CD61+ platelet-sized particles, reminiscent of the large platelets observed in vivo. FlnA stabilizes the platelet von Willebrand factor receptor, as surface expression of von Willebrand factor receptor components is normal on FlnA-null MKs but decreased on FlnA-null platelets. Further, FlnA-null platelets contain multiple GPIbα degradation products and have increased expression of the ADAM17 and MMP9 metalloproteinases. Together, the findings indicate that FlnA-null MKs prematurely release large and fragile platelets that are removed rapidly from the circulation by macrophages. PMID:21652675

  19. Platelet adhesion via glycoprotein IIb integrin is critical for atheroprogression and focal cerebral ischemia: an in vivo study in mice lacking glycoprotein IIb.

    PubMed

    Massberg, Steffen; Schürzinger, Katrin; Lorenz, Michael; Konrad, Ildiko; Schulz, Christian; Plesnila, Nikolaus; Kennerknecht, Elisabeth; Rudelius, Martina; Sauer, Susanne; Braun, Siegmund; Kremmer, Elisabeth; Emambokus, Nikla R; Frampton, Jon; Gawaz, Meinrad

    2005-08-23

    The platelet glycoprotein (GP) IIb/IIIa integrin binds to fibrinogen and thereby mediates platelet aggregation. Here, we addressed the role of GP IIb for platelet adhesion and determined the relevance of platelet GP IIb for the processes of atherosclerosis and cerebral ischemia-reperfusion (I/R) injury. GP IIb(-/-) mice were generated and bred with ApoE(-/-) animals to create GP IIb(-/-)ApoE(-/-) mice. Platelet adhesion to the mechanically injured or atherosclerotic vessel wall was monitored by in vivo video fluorescence microscopy. In the presence of GP IIb, vascular injury and early atherosclerosis induced platelet adhesion in the carotid artery (CA). In contrast, platelet adhesion was significantly reduced in the absence of GP IIb integrin (P<0.05). To address the contribution of platelet GP IIb to atheroprogression, we determined atherosclerotic lesion formation in the CA and aortic arch (AA) of GP IIb(+/+)ApoE(-/-) or GP IIb(-/-)ApoE(-/-) mice. Interestingly, the absence of GP IIb attenuated lesion formation in CA and AA, indicating that platelets, via GP IIb, contribute substantially to atherosclerosis. Next, we assessed the implication of GP IIb for cerebral I/R injury. We observed that after occlusion of the middle cerebral artery, the cerebral infarct size was drastically reduced in mice lacking GP IIb compared with wild-types. These findings show for the first time in vivo that GP IIb not only mediates platelet aggregation but also triggers platelet adhesion to exposed extracellular matrices and dysfunctional endothelial cells. In a process strictly involving GP IIb, platelets, which are among the first blood cells to arrive at the scene of endothelial dysfunction, contribute essentially to atherosclerosis and cerebral I/R injury.

  20. Platelet glycoproteins associated with aspirin-treatment upon platelet activation

    PubMed Central

    Shah, Punit; Yang, Weiming; Sun, Shisheng; Pasay, Jered; Faraday, Nauder; Zhang, Hui

    2017-01-01

    Platelet glycoproteins are known to play central roles in hemostasis and vascular integrity and have pathologic roles in vascular occlusive diseases such as myocardial infarction and stroke. Characterizing glycoproteins within and secreted by platelets can provide insight into the mechanisms that underlie vascular pathologies and the therapeutic benefits or failure of anti-platelet agents. To study the impact of aspirin, which is commonly prescribed for primary and secondary cardiovascular prevention, on the platelet glycoproteome, we evaluated washed platelets from ten donors. The platelet glycoproteome, was studied using an iTRAQ in resting and stimulated states and with and without aspirin treatment. Using solid phase extraction of glycosite-containing peptides (SPEG), we were able to identify 799 unique N-linked glycosylation sites (glycosites) in platelets, representing the largest and the most comprehensive analysis to date. We were able to identity a number of glycoproteins impacted by aspirin treatment, which we validated using global proteomics analysis of platelets and their secreted proteins. In our analyses, metallopeptidase inhibitor 1 (TIMP1) was the single most significantly affected glycoprotein by aspirin treatment. ELISA assays confirmed proteomic results and validated our strategy. Functional analysis demonstrated that TIMP1 levels were highly correlated with platelet reactivity in vitro, with a correlation coefficient of −0.5. The release of TIMP1 from platelets, which was previously unknown to be affected by aspirin treatment, may play important roles in hemostasis and/or vascular integrity. If validated, our findings may be useful for developing assays that assess platelet response to aspirin or other anti-platelet therapies. PMID:27452734

  1. Platelet-TLR7 mediates host survival and platelet count during viral infection in the absence of platelet-dependent thrombosis

    PubMed Central

    Koupenova, Milka; Vitseva, Olga; MacKay, Christopher R.; Beaulieu, Lea M.; Benjamin, Emelia J.; Mick, Eric; Kurt-Jones, Evelyn A.; Ravid, Katya

    2014-01-01

    Viral infections have been associated with reduced platelet counts, the biological significance of which has remained elusive. Here, we show that infection with encephalomyocarditis virus (EMCV) rapidly reduces platelet count, and this response is attributed to platelet Toll-like receptor 7 (TLR7). Platelet-TLR7 stimulation mediates formation of large platelet-neutrophil aggregates, both in mouse and human blood. Intriguingly, this process results in internalization of platelet CD41-fragments by neutrophils, as assessed biochemically and visualized by microscopy, with no influence on platelet prothrombotic properties. The mechanism includes TLR7-mediated platelet granule release, translocation of P-selectin to the cell surface, and a consequent increase in platelet-neutrophil adhesion. Viral infection of platelet-depleted mice also led to increased mortality. Transfusion of wild-type, TLR7-expressing platelets into TLR7-deficient mice caused a drop in platelet count and increased survival post EMCV infection. Thus, this study identifies a new link between platelets and their response to single-stranded RNA viruses that involves activation of TLR7. Finally, platelet-TLR7 stimulation is independent of thrombosis and has implications to the host immune response and survival. PMID:24755410

  2. Platelet participation in the pathogenesis of dermonecrosis induced by Loxosceles gaucho venom.

    PubMed

    Tavares, F L; Peichoto, M E; Marcelino, J R; Barbaro, K C; Cirillo, M C; Santoro, M L; Sano-Martins, I S

    2016-06-01

    Loxosceles gaucho spider venom induces in vitro platelet activation and marked thrombocytopenia in rabbits. Herein, we investigated the involvement of platelets in the development of the dermonecrosis induced by L. gaucho venom, using thrombocytopenic rabbits as a model. L. gaucho venom evoked a drop in platelet and neutrophil counts 4 h after venom injection. Ecchymotic areas at the site of venom inoculation were noticed as soon as 4 h in thrombocytopenic animals but not in animals with initial normal platelet counts. After 5 days, areas of scars in thrombocytopenic animals were also larger, evidencing the marked development of lesions in the condition of thrombocytopenia. Histologically, local hemorrhage, collagen fiber disorganization, and edema were more severe in thrombocytopenic animals. Leukocyte infiltration, predominantly due to polymorphonuclears, was observed in the presence or not of thrombocytopenia. Thrombus formation was demonstrated by immunohistochemistry at the microvasculature, and it occurred even under marked thrombocytopenia. Taken together, platelets have an important role in minimizing not only the hemorrhagic phenomena but also the inflammatory and wound-healing processes, suggesting that cutaneous loxoscelism may be aggravated under thrombocytopenic conditions. © The Author(s) 2015.

  3. Propionibacterium acnes lacks the capability to proliferate in platelet concentrates.

    PubMed

    Störmer, M; Kleesiek, K; Dreier, J

    2008-04-01

    Propionibacterium acnes is considered to be one of the most frequent contaminants of platelet concentrates (PCs) when anaerobic culture-based detection methods are used. But Propionibacteria are often detected too late when blood products have already been transfused. Therefore, its transfusion relevance is still demanding clarification because studies of the outcome of patients transfused with P. acnes-contaminated PCs are still uncommon. In this study, we monitored clinical effects in patients after transfusion of PCs, which were detected too late in sterility testing. Furthermore, we assessed the bacterial proliferation of Propionibacterium species seeded into PCs to clarify their significance for platelet bacteria screening. In the look-back process, we followed the route of the putative contaminated PC units from storage to transfusion. In the in vitro study, PCs were inoculated with 1-100 colony-forming unit (CFU)/ml of clinical isolates of Propionibacteria (n = 10). Sampling was performed during 10-day aerobic storage at 22 degrees C. The presence of bacteria was assessed by plating culture and automated BacT/Alert culture system. Propionibacterium acnes shows slow or no growth under PC storage conditions. Clinical signs of adverse events after transfusion of potentially contaminated PC units were not reported. Propionibacteria do not proliferate under PC storage conditions and therefore may be missed or detected too late when blood products have already been transfused.

  4. The use of platelet-rich fibrin as a hemostatic material in oral soft tissues.

    PubMed

    de Almeida Barros Mourão, Carlos Fernando; Calasans-Maia, Mônica Diuana; de Mello Machado, Rafael Coutinho; de Brito Resende, Rodrigo Figueiredo; Alves, Gutemberg Gomes

    2018-06-26

    The control of postoperative bleeding represents one of the main intercurrent events associated with soft tissue surgical procedures in the oral cavity. In this context, platelet-rich fibrin (PRF) membranes are materials with great potential for optimizing soft tissue healing and induction of hemostasis. This interventional case series describes the treatment of 10 patients with excisional biopsy of benign oral cavity lesions, following a screening sequence at the surgery clinic of a Brazilian dental school between the years of 2015 and 2017. After treatment with PRF, patients presented mean time for postoperative hemostasis of 10.3 ± 2.5 s, requiring the average use of three membranes to cover the surgical area. The results suggest that the use of platelet-rich fibrin membranes may represent a feasible alternative hemostatic material for the treatment of oral lesions.

  5. Platelet-Derived MRP-14 Induces Monocyte Activation in Patients With Symptomatic Peripheral Artery Disease.

    PubMed

    Dann, Rebecca; Hadi, Tarik; Montenont, Emilie; Boytard, Ludovic; Alebrahim, Dornaszadat; Feinstein, Jordyn; Allen, Nicole; Simon, Russell; Barone, Krista; Uryu, Kunihiro; Guo, Yu; Rockman, Caron; Ramkhelawon, Bhama; Berger, Jeffrey S

    2018-01-02

    Peripheral artery disease (PAD), a diffuse manifestation of atherothrombosis, is a major cardiovascular threat. Although platelets are primary mediators of atherothrombosis, their role in the pathogenesis of PAD remains unclear. The authors sought to investigate the role of platelets in a cohort of symptomatic PAD. The authors profiled platelet activity, mRNA, and effector roles in patients with symptomatic PAD and in healthy controls. Patients with PAD and carotid artery stenosis were recruited into ongoing studies (NCT02106429 and NCT01897103) investigating platelet activity, platelet RNA, and cardiovascular disease. Platelet RNA sequence profiling mapped a robust up-regulation of myeloid-related protein (MRP)-14 mRNA, a potent calcium binding protein heterodimer, in PAD. Circulating activated platelets were enriched with MRP-14 protein, which augmented the expression of the adhesion mediator, P-selectin, thereby promoting monocyte-platelet aggregates. Electron microscopy confirmed the firm interaction of platelets with monocytes in vitro and colocalization of macrophages with MRP-14 confirmed their cross talk in atherosclerotic manifestations of PAD in vivo. Platelet-derived MRP-14 was channeled to monocytes, thereby fueling their expression of key PAD lesional hallmarks and increasing their directed locomotion, which were both suppressed in the presence of antibody-mediated blockade. Circulating MRP-14 was heightened in the setting of PAD, significantly correlated with PAD severity, and was associated with incident limb events. The authors identified a heightened platelet activity profile and unraveled a novel immunomodulatory effector role of platelet-derived MRP-14 in reprograming monocyte activation in symptomatic PAD. (Platelet Activity in Vascular Surgery and Cardiovascular Events [PACE]; NCT02106429; and Platelet Activity in Vascular Surgery for Thrombosis and Bleeding [PIVOTAL]; NCT01897103). Copyright © 2018 American College of Cardiology Foundation

  6. Platelet von Willebrand factor in Hermansky-Pudlak syndrome.

    PubMed

    McKeown, L P; Hansmann, K E; Wilson, O; Gahl, W; Gralnick, H R; Rosenfeld, K E; Rosenfeld, S J; Horne, M K; Rick, M E

    1998-10-01

    The Hermansky-Pudlak Syndrome (HPS) is an autosomal recessive inherited disorder characterized by oculocutaneous albinism, tissue accumulation of ceroid pigment, and a mild to moderate bleeding diathesis attributed to storage-pool deficient (SPD) platlets. Patients have platelet aggregation and release abnormalities. In addition, low levels of plasma von Willebrand factor (vWF) antigen in some HPS patients have been associated with a greater bleeding tendency than would be predicted from either condition alone. Other HPS patients have severe bleeding despite normal levels of plasma vWF, suggesting that at least one additional factor is responsible for their bleeding diathesis. Because platelet vWF levels have been well correlated with clinical bleeding times in patients with von Willebrand's disease, we have measured the platelet vWF activity and antigen levels in 30 HPS patients and have attempted to correlate their clinical bleeding with these values. The platelet vWF activity levels in patients was significantly lower than that of normal subjects (P < 0.0001). The patients as a group also had slightly lower values of plasma vWF activity when compared with normals (P-0.03). In 11 of the HPS patients, the multimeric structure of plasma vWF showed a decrease in the high molecular weight multimers and an increase in the low molecular weight multimers. In correlating the platelet and plasma vWF values with the bleeding histories, we were not able to show a predictable relationship in the majority of the patients.

  7. Comparison of bacterial attachment to platelet bags with and without preconditioning with plasma.

    PubMed

    Loza-Correa, M; Kalab, M; Yi, Q-L; Eltringham-Smith, L J; Sheffield, W P; Ramirez-Arcos, S

    2017-07-01

    Canadian Blood Services produces apheresis and buffy coat pooled platelet concentrates (PCs) stored in bags produced by two different manufacturers (A and B, respectively), both made of polyvinyl chloride-butyryl trihexyl citrate. This study was aimed at comparing Staphylococcus epidermidis adhesion to the inner surface of both bag types in the presence or absence of plasma factors. Sets (N = 2-6) of bags type A and B were left non-coated (control) or preconditioned with platelet-rich, platelet-poor or defibrinated plasma (PRP, PPP and DefibPPP, respectively). Each bag was inoculated with a 200-ml S. epidermidis culture adjusted to 0·5 colony-forming units/ml. Bags were incubated under platelet storage conditions for 7 days. After culture removal, bacteria attached to the plastic surface were either dislodged by sonication for bacterial quantification or examined in situ by scanning electron microscopy (SEM). Higher bacterial adhesion was observed to preconditioned PC bags than control containers for both bag types (P < 0·0001). Bacterial attachment to preconditioned bags was confirmed by SEM. Bacteria adhered equally to both types of containers in the presence of PRP, PPP and DefibPPP residues (P > 0·05). By contrast, a significant increase in bacterial adherence was observed to type A bags compared with type B bags in the absence of plasma (P < 0·05) [Correction added on 16 June 2017, after first online publication: this sentence has been corrected]. The ability of S. epidermidis to adhere to preconditioned platelet collection bags depends on the presence of plasma factors. Future efforts should be focused on reducing plasma proteins' attachment to platelet storage containers to decrease subsequent bacterial adhesion. © 2017 International Society of Blood Transfusion.

  8. Skin lesions in hospitalized cases of dengue Fever.

    PubMed

    Saleem, Khawer; Shaikh, Irfan

    2008-10-01

    To determine the frequency and types of skin lesions in cases of dengue fever in patients admitted in three hospitals of Karachi. Case series. Three tertiary care hospitals of Karachi, from November 2006 to February 2007. One hundred patients of dengue fever with positive anti-dengue Immunoglobulin M (IgM) serology were included in the study. The admitted patients in PNS Shifa Hospital, Jinnah Postgraduate Medical Centre (JPMC) and Civil Hospital, Karachi were selected for the study. Presenting features were noted. The patients were physically examined for the presence of skin and mucosal lesions and findings were recorded. Total and Differential Leukocyte Count (TLC and DLC), platelet count and Liver Function Tests (LFTs) were done in all the patients. All the patients had low leukocyte and low platelet counts. The common presenting symptoms were high-grade fever with or without rigors, headache, body aches, backache, vomiting, sore throat with cough and generalized weakness (seen in 86% patients). The uncommon presenting features were diarrhea, abdominal pain, bleeding from gums and nosebleeds (seen in 14% patients). Sixty-eight (68%) patients had skin lesions. The most common skin presentation was generalized macular blanchable erythema involving trunk and limbs, seen in 44 (65%) cases. Discrete petechial lesions were seen on various body areas in 24 (35%) cases. Palmer erythema was seen in 20 (30%) patients. Generalized itching was seen in 16 (23%) cases. Isolated itching of palms and soles was seen in 20 (30%) cases. Twenty-eight (28%) patients had deranged LFTs. Out of those, 4 patients had raised serum bilirubin level whereas rest of the 24 had raised ALT. Dengue fever commonly presents with specific skin lesions. The skin lesions can be a clue to the diagnosis in difficult cases.

  9. Relations of Platelet Indices with Endometrial Hyperplasia and Endometrial Cancer.

    PubMed

    Karateke, Atilla; Kaplanoglu, Mustafa; Baloglu, Ali

    2015-01-01

    Platelets are blood elements thought to play a role in the immune system and therefore tumor development and metastasis. Platelet activation parameters such as mean platelet volume (MPV), platelet distribution width (PDW), and plateletcrit (PCT) can be easily evaluated with the whole blood count and have been studied as markers of systemic inflammatory responses in various cancer types. Our aim in this study was to evaluate the correlation between endometrial pathologies and MPV, PDW and PCT. A total of 194 patients who presented to our clinic with abnormal vaginal bleeding were included in our study. The patients were divided into 3 groups (endometrial hyperplasia, endometrial cancer, control) according to their pathology results. The groups were compared for MPV, PDW, and PCT values obtained from the blood samples taken on endometrial biopsy day. The endometrial cancer patients were the oldest group (p=0.04). There was no significant difference between the three groups in terms of white blood cell count (WBC), platelet count (PC), and hemoglobin (Hb) level. The highest MPV (p<0.001), PDW (p=0.002), and PCT (p<0.001) levels were in the endometrial cancer group, and the lowest levels were in the control group. The easy evaluation of platelet parameters in patients who are suspected of having endometrial pathology is a significant advantage. We found MPV, PDW, and PCT to be correlated with the severity of endometrial pathology with the highest values in endometrial cancer. Studies to be conducted together with different laboratory parameters will further help evaluate the diagnosis and severity of endometrial cancer and precursor lesions.

  10. Moisture sorption characteristics of freeze-dried human platelets*

    PubMed Central

    Xu, Meng-jie; Chen, Guang-ming; Fan, Ju-li; Liu, Jin-hui; Xu, Xian-guo; Zhang, Shao-zhi

    2011-01-01

    Freeze-drying is a promising method for a long-term storage of human platelets. The moisture sorption characteristics of freeze-dried human platelets (FDHPs) were studied in this paper. The moisture sorption isotherms of FDHPs and freeze-dried lyophilization buffer (FDLB) were measured at 4, 25, and 37 °C. The experimental data were fitted to Brunauer-Emmett-Teller (BET) and Guggenheim-Anderson-de Boer (GAB) equations. There were no significant statistical differences (P>0.05) between the sorption characteristics of FDHPs and FDLB at 4 and 25 °C, while FDHPs absorbed more water at 37 °C. The net isosteric heat of sorption was derived. The heat for FDHPs showed an abnormal negative value at low moisture contents when 25 and 37 °C data were used. Dynamic sorption experiments were carried out at 25 °C with environmental water activity controlled at 0.75, 0.85, and 0.90. The moisture diffusion coefficient was fitted to be 8.24×10−12 m2/s when experimental data at initial time were used. These results would be helpful in choosing prehydration and storage condition for FDHPs. PMID:21370506

  11. Insomnia, platelet serotonin and platelet monoamine oxidase in chronic alcoholism.

    PubMed

    Nenadic Sviglin, Korona; Nedic, Gordana; Nikolac, Matea; Mustapic, Maja; Muck-Seler, Dorotea; Borovecki, Fran; Pivac, Nela

    2011-08-18

    Insomnia is a common sleep disorder frequently occurring in chronic alcoholic patients. Neurobiological basis of insomnia, as well as of alcoholism, is associated with disrupted functions of the main neurotransmitter systems, including the serotonin (5-hydroxytryptamine, 5-HT) system. Blood platelets are considered a limited peripheral model for the central 5-HT neurons, since both platelets and central 5-HT synaptosomes have similar dynamics of 5-HT. Platelet 5-HT concentration and platelet monoamine oxidase type B (MAO-B) are assumed to represent biomarkers for particular symptoms and behaviors in psychiatric disorders. The hypothesis of this study was that platelet 5-HT concentration and platelet MAO-B activity will be altered in chronic alcoholic patients with insomnia compared to comparable values in patients without insomnia. The study included 498 subjects: 395 male and 103 female medication-free patients with alcohol dependence and 502 healthy control subjects: 325 men and 177 women. The effects of early, middle and late insomnia (evaluated using the Hamilton Depression Rating Scale), as well as sex, age and smoking on platelet 5-HT concentration and platelet MAO-B activity were evaluated using one-way ANOVA and multiple regression analysis by the stepwise method. Platelet 5-HT concentration, but not platelet MAO-B activity, was significantly reduced in alcoholic patients with insomnia compared to patients without insomnia. Multiple regression analysis revealed that platelet 5-HT concentration was affected by middle insomnia, smoking and sex, while platelet MAO activity was affected only by sex and age. The present and previous data suggest that platelet 5-HT concentration might be used, after controlling for sex and smoking, as a biomarker for insomnia in alcoholism, PTSD and in rotating shift workers. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  12. [Platelet allo-antibodies identification strategies for preventing and managing platelet refractoriness].

    PubMed

    Basire, A; Picard, C

    2014-11-01

    Platelet refractoriness is a serious complication for patients receiving recurrent platelet transfusions, which can be explained by non-immune and immune causes. Human Leukocyte Antigens (HLA) allo-immunization, especially against HLA class I, is the major cause for immune platelet refractoriness. To a lesser extent, allo-antibodies against specific Human Platelet Antigen (HPA) are also involved. Pregnancy, transplantation and previous transfusions can lead to allo-immune reaction against platelet antigens. After transfusion, platelet count is decreased by accelerated platelet destruction related to antibodies fixation on incompatible platelet antigens. New laboratory tests for allo-antibodies identification were developed to improve sensibility and specificity, especially with the LUMINEX(®) technology. The good use and interpretation of these antibodies assays can improve strategies for platelet refractoriness prevention and management with a patient adapted response. Compatible platelets units can be selected according to their identity with recipient typing or immune compatibility regarding HLA or HPA antibodies or HLA epitope compatibility. Prospective studies are needed to further confirm the clinical benefit of new allo-antibodies identification methods and consensus strategies for immune platelet refractoriness management. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  13. IMMUNOREACTIONS INVOLVING PLATELETS

    PubMed Central

    Shulman, N. Raphael

    1958-01-01

    Quantitative aspects of platelet agglutination and inhibition of clot retraction by the antibody of quinidine purpura were described. The reactions appeared to depend on formation of types of antibody-quinidine-platelet complexes which could fix complement but complement was not necessary for these reactions. Complement fixation was at least 10 times more sensitive than platelet agglutination or inhibition of clot retraction for measurement and detection of antibody activity. Although it has been considered that antibodies of drug purpura act as platelet lysins in the presence of complement and that direct lysis of platelets accounts for development of thrombocytopenia in drug purpura, the present study suggests that attachment of antibody produces a change in platelets which is manifested in vitro only by increased susceptibility to non-specific factors which can alter the stability of platelets in the absence of antibody. The attachment of antibody to platelets in vivo may only indirectly affect platelet survival. In contrast to human platelets, dog, rabbit, and guinea pig platelets, and normal or trypsin-treated human red cells did not agglutinate, fix complement, or adsorb antibody; and intact human endothelial cells did not fix complement or adsorb antibody. Rhesus monkey platelets were not agglutinated by the antibody but did adsorb antibody and fix complement although their activity in these reactions differed quantitatively from that of human platelets. Cinchonine could be substituted for quinidine in agglutination and inhibition of clot retraction reactions but quinine and cinchonidine could not. Attempts to cause passive anaphylaxis in guinea pigs with the antibody of quinidine purpura were not successful. PMID:13525580

  14. Extended storage and glucose exhaustion are associated with apoptotic changes in platelets stored in additive solution.

    PubMed

    Johnson, Lacey; Schubert, Peter; Tan, Shereen; Devine, Dana V; Marks, Denese C

    2016-02-01

    The storage of platelets (PLTs) in additive solution (AS) may facilitate improved PLT quality and possibly extension of the PLT shelf life. A minimum amount of plasma is required when PLTs are stored in AS, as a source of glucose. The aim of this study was to assess the effect of reducing the plasma carryover to 20% on PLT quality when stored in SSP+ for an extended period. Using a pool-and-split design, buffy coat-derived PLTs were stored in either 30% plasma/SSP+ or 20% plasma/SSP+. In vitro analyses were carried out to Day 10. Metabolites and markers of PLT activation and apoptosis were measured using a blood gas analyzer and flow cytometry. PLT apoptotic protein expression was investigated by Western blotting. Glucose exhaustion occurred in the 20% plasma group between Day 7 and Day 10. The surface expression of P-selectin and PAC-1 was comparable on Day 10 in both groups, suggesting that the PLTs were not activated. However, the exposure of phosphatidylserine and the number of phosphatidylserine-positive microparticles were significantly higher in the 20% group on Day 10. The expression of the proapoptotic proteins Bak, Bax, and cleaved caspase-3 were higher in the 20% plasma group by Day 7 of storage, compared to the 30% plasma group. Exhaustion of glucose was associated with a proapoptotic phenotype. Results such as these should be considered before extending the PLT shelf life beyond 7 days, particularly when stored in ASs lacking glucose with low plasma carryover. © 2015 AABB.

  15. Platelet-Rich Plasma and Platelet Gel: A Review

    PubMed Central

    Everts, Peter A.M.; Knape, Johannes T.A.; Weibrich, Gernot; Schönberger, Jacques P.A.M.; Hoffmann, Johannes; Overdevest, Eddy P.; Box, Henk A.M.; van Zundert, André

    2006-01-01

    Abstract: Strategies to reduce blood loss and transfusion of allogeneic blood products during surgical procedures are important in modern times. The most important and well-known autologous techniques are preoperative autologous predonation, hemodilution, perioperative red cell salvage, postoperative wound blood autotransfusion, and pharmacologic modulation of the hemostatic process. At present, new developments in the preparation of preoperative autologous blood component therapy by whole blood platelet-rich plasma (PRP) and platelet-poor plasma (PPP) sequestration have evolved. This technique has been proven to reduce the number of allogeneic blood transfusions during open heart surgery and orthopedic operations. Moreover, platelet gel and fibrin sealant derived from PRP and PPP mixed with thrombin, respectively, can be exogenously applied to tissues to promote wound healing, bone growth, and tissue sealing. However, to our disappointment, not many well-designed scientific studies are available, and many anecdotic stories exist, whereas questions remain to be answered. We therefore decided to study perioperative blood management in more detail with emphasis on the application and production of autologous platelet gel and the use of fibrin sealant. This review addresses a large variety of aspects relevant to platelets, platelet-rich plasma, and the application of platelet gel. In addition, an overview of recent animal and human studies is presented. PMID:16921694

  16. Stability validation of paraformaldehyde-fixed samples for the assessment of the platelet PECAM-1, P-selectin, and PAR-1 thrombin receptor by flow cytometry.

    PubMed

    Atar, Oliver D; Eisert, Christian; Pokov, Ilya; Serebruany, Victor L

    2010-07-01

    Sample fixation for storage and/or transportation represents an unsolved challenge for multicenter clinical trials assessing serial changes in platelet activity, or monitoring various antiplatelet regimens. Whole blood flow cytometry represents a major advance in defining platelet function, although special training and expensive equipment is required. We sought to determine how fixation with 2% paraformaldehyde (PFA), and storage of blood samples over 1 week affects the flow cytometry readings for both intact and thrombin-activating four major surface platelet receptors. Whole blood platelet expression of PECAM-1, P-selectin, PAR-1 inactive receptor (SPAN-12), and cleaved (WEDE-15) epitope was assessed immediately after blood draw, after staining with 2% PFA, and at day 1, 3, 5, and 7. The study was performed in 6 volunteers with multiple risk factors for vascular disease, not receiving any antiplatelet agents. Staining with PFA resulted in a slight decrease of fluorescence intensity, especially for PECAM-1, while antigen expression at day 1, 3 and 5 remains consistent, and highly reproducible. At day 7 there was a small but inconsistent trend towards diminished fluorescence intensity. The platelet data were consistent while validated with the isotype-matched irrelevant antibody. These data suggest that there is a 5 day window to perform final flow cytometry readings of whole blood PFA-fixed inactivated platelet samples. In contrast, thrombin activation cause gradual loss of flow cytometry signal, and cannot be recommended for long-term storage. This is critical logistic information for conducting multicenter platelet substudies within the framework of major clinical trials.

  17. Assessment of Platelet Function in Traumatic Brain Injury-A Retrospective Observational Study in the Neuro-Critical Care Setting.

    PubMed

    Lindblad, Caroline; Thelin, Eric Peter; Nekludov, Michael; Frostell, Arvid; Nelson, David W; Svensson, Mikael; Bellander, Bo-Michael

    2018-01-01

    Despite seemingly functional coagulation, hemorrhagic lesion progression is a common and devastating condition following traumatic brain injury (TBI), stressing the need for new diagnostic techniques. Multiple electrode aggregometry (MEA) measures platelet function and could aid in coagulopathy assessment following TBI. The aims of this study were to evaluate MEA temporal dynamics, influence of concomitant therapy, and its capabilities to predict lesion progression and clinical outcome in a TBI cohort. Adult TBI patients in a neurointensive care unit that underwent MEA sampling were retrospectively included. MEA was sampled if the patient was treated with antiplatelet therapy, bled heavily during surgery, or had abnormal baseline coagulation values. We assessed platelet activation pathways involving the arachidonic acid receptor (ASPI), P2Y 12 receptor, and thrombin receptor (TRAP). ASPI was the primary focus of analysis. If several samples were obtained, they were included. Retrospective data were extracted from hospital charts. Outcome variables were radiologic hemorrhagic progression and Glasgow Outcome Scale assessed prospectively at 12 months posttrauma. MEA levels were compared between patients on antiplatelet therapy. Linear mixed effect models and uni-/multivariable regression models were used to study longitudinal dynamics, hemorrhagic progression and outcome, respectively. In total, 178 patients were included (48% unfavorable outcome). ASPI levels increased from initially low values in a time-dependent fashion ( p  < 0.001). Patients on cyclooxygenase inhibitors demonstrated low ASPI levels ( p  < 0.001), while platelet transfusion increased them ( p  < 0.001). The first ASPI ( p  = 0.039) and TRAP ( p  = 0.009) were significant predictors of outcome, but not lesion progression, in univariate analyses. In multivariable analysis, MEA values were not independently correlated with outcome. A general longitudinal trend of MEA is

  18. [Platelet function in acute myeloid leukemia. II. Aggregation of isolated platelets].

    PubMed

    Zawilska, K; Komarnicki, M; Mańka, B

    1978-01-01

    In 22 patients with acute myeloid leukaemia (17 cases of myeloblastic leukaemia, 4 cases of myelomonocytic leukaemia and 1 case of undifferentiated-cell leukaemia) platelets were isolated from the plasma by the method of Nicholls and Hampton as modified by Levy-Toledano by centrifugation in albumin gradient. The aim of platelet isolation was their "concentration" in cases of thrombocytopenia to values making possible aggregation tests, and platelet separation from the influence of plasma factors. Then aggregation of isolated platelets caused by ADP was studied. In 16 out of 22 patients a fall of aggregation was observed, with the mean values of aggregation rate and intensity were significantly lower. Parallelly done determinations of aggregating activity released from the platelets by thrombin showed lower values as compared with platelets from healthy subjects. In might be thought, in this connection, that the demonstrated reduction of isolated platelets is associated with a diminution of the nucleotide pool or disturbances of the platelet release reaction. The disturbances of the platelet release reaction. The disturbances of aggregation of isolated platelets and reduction of the aggregating activity were most pronounced in acute myelomonocytic leukaemia.

  19. Disorders of Platelet Function

    PubMed Central

    Huebsch, Lothar B.; Harker, Laurence A.

    1981-01-01

    Platelets play an important role in hemostasis, and alterations in platelet function may be the cause of abnormal bleeding in a wide variety of congenital and acquired clinical disorders. Platelet dysfunction may be classified as disorders of (1) substrate connective tissue, (2) adhesion, (3) aggregation and (4) platelet-release reaction. The congenital defects of platelet function, although uncommon, have provided important insights into platelet physiology and pathophysiology and, as a group, are less common, better characterized and more readily classified than the acquired defects. The severity of bleeding resulting from platelet dysfunction varies greatly and is substantially increased when another defect of hemostasis coexists. A disorder of platelet function is suspected on the basis of the history and physical examination and is confirmed by the finding of a prolonged bleeding time in the presence of an adequate number of platelets. A specific diagnosis often requires measurements of the factor VIII and von Willebrand factor complex and other tests of platelet function. Some of these tests may be available only in specialized laboratories. Therapy for bleeding episodes resulting from platelet dysfunction is directed at (1) removing or treating the underlying cause of the platelet disorder; (2) replacing the missing plasma cofactors needed to support normal platelet function (such as by the transfusion of cryoprecipitate in patients with von Willebrand disease, and (3) transfusing functional platelets in the form of platelet concentrates in patients with disorders of intrinsic platelet dysfunction. ImagesFigure 1.Figure 2.Figure 3. PMID:7013276

  20. Autologous Bone Marrow Concentrates and Concentrated Growth Factors Accelerate Bone Regeneration After Enucleation of Mandibular Pathologic Lesions.

    PubMed

    Talaat, Wael M; Ghoneim, Mohamed M; Salah, Omar; Adly, Osama A

    2018-02-23

    Stem cell therapy is a revolutionary new way to stimulate mesenchymal tissue regeneration. The platelets concentrate products started with platelet-rich plasma (PRP), followed by platelet-rich fibrin (PRF), whereas concentrated growth factors (CGF) are the latest generation of the platelets concentrate products which were found in 2011. The aim of the present study was to evaluate the potential of combining autologous bone marrow concentrates and CGF for treatment of bone defects resulting from enucleation of mandibular pathologic lesions. Twenty patients (13 males and 7 females) with mandibular benign unilateral lesions were included, and divided into 2 groups. Group I consisted of 10 patients who underwent enucleation of the lesions followed by grafting of the bony defects with autologous bone marrow concentrates and CGF. Group II consisted of 10 patients who underwent enucleation of the lesions without grafting (control). Radiographic examinations were done immediately postoperative, then at 1, 3, 6, and 12 months, to evaluate the reduction in size and changes in bone density at the bony defects. Results indicated a significant increase in bone density with respect to the baseline levels in both groups (P < 0.05). The increase in bone density was significantly higher in group I compared with group II at the 6- and 12-month follow-up examinations (P < 0.05). The percent of reduction in the defects' size was significantly higher in group I compared with group II after 12 months (P = 0.00001). In conclusion, the clinical application of autologous bone marrow concentrates with CGF is a cost effective and safe biotechnology, which accelerates bone regeneration and improves the density of regenerated bone.

  1. Phorbol ester stimulates calcium sequestration in saponized human platelets

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yoshida, K.; Nachmias, V.T.

    1987-11-25

    When platelets are activated by agonists, calcium (Ca2+) is released from an intracellular storage site. Recent studies using fura-2 show that, after thrombin stimulation, the rise in free calcium is transient and returns to base-line levels in 2-3 min, while the transient following ADP stimulation lasts only 15-20 s. We reported previously that the phorbol ester 12,13-phorbol myristate acetate (PMA), added at nanomolar levels after thrombin, immediately accelerated the rate of return of calcium to the base line severalfold. In the present study, we used both intact and saponized platelets to determine whether this is due to stimulation of calciummore » sequestration. Using fura-2 and intact platelets, we found 1) that PMA stimulated the restoration of free Ca2+ levels after ADP as well as after thrombin, and 2) that H-7, an inhibitor of protein kinase C (Ca2+/phospholipid-dependent enzyme), slowed the return of Ca2+ to baseline levels. Using saponized platelets, we also found 3) that pretreatment of platelets with PMA before saponin treatment increased the ATP-dependent /sup 45/Ca2+ uptake 2-fold, with a half-maximal effect at 5 nm; 4) that most of the Ca2+ released by ionomycin or by myoinositol 1,4,5-trisphosphate; and 5) that a GTP-binding protein inhibitor, guanosine 5'-O-(2-thiodiphosphate), decreased basal or PMA-stimulated /sup 45/Ca2+ uptake in saponin-treated platelets. Our data suggest that activation of protein kinase C stimulates the sequestration of Ca2+ independently of cAMP or myoinositol 1,4,5-trisphosphate.« less

  2. Dynamic adhesion of eryptotic erythrocytes to immobilized platelets via platelet phosphatidylserine receptors.

    PubMed

    Walker, Britta; Towhid, Syeda T; Schmid, Evi; Hoffmann, Sascha M; Abed, Majed; Münzer, Patrick; Vogel, Sebastian; Neis, Felix; Brucker, Sara; Gawaz, Meinrad; Borst, Oliver; Lang, Florian

    2014-02-01

    Glucose depletion of erythrocytes triggers suicidal erythrocyte death or eryptosis, which leads to cell membrane scrambling with phosphatidylserine exposure at the cell surface. Eryptotic erythrocytes adhere to endothelial cells by a mechanism involving phosphatidylserine at the erythrocyte surface and CXCL16 as well as CD36 at the endothelial cell membrane. Nothing has hitherto been known about an interaction between eryptotic erythrocytes and platelets, the decisive cells in primary hemostasis and major players in thrombotic vascular occlusion. The present study thus explored whether and how glucose-depleted erythrocytes adhere to platelets. To this end, adhesion of phosphatidylserine-exposing erythrocytes to platelets under flow conditions was examined in a flow chamber model at arterial shear rates. Platelets were immobilized on collagen and further stimulated with adenosine diphosphate (ADP, 10 μM) or thrombin (0.1 U/ml). As a result, a 48-h glucose depletion triggered phosphatidylserine translocation to the erythrocyte surface and augmented the adhesion of erythrocytes to immobilized platelets, an effect significantly increased upon platelet stimulation. Adherence of erythrocytes to platelets was blunted by coating of erythrocytic phosphatidylserine with annexin V or by neutralization of platelet phosphatidylserine receptors CXCL16 and CD36 with respective antibodies. In conclusion, glucose-depleted erythrocytes adhere to platelets. The adhesive properties of platelets are augmented by platelet activation. Erythrocyte adhesion to immobilized platelets requires phosphatidylserine at the erythrocyte surface and CXCL16 as well as CD36 expression on platelets. Thus platelet-mediated erythrocyte adhesion may foster thromboocclusive complications in diseases with stimulated phosphatidylserine exposure of erythrocytes.

  3. Bacterial screening by flow cytometry offers potential for extension of platelet storage: results of 14 months of active surveillance.

    PubMed

    Vollmer, T; Engemann, J; Kleesiek, K; Dreier, J

    2011-06-01

    Bacterial contamination is currently the major infectious hazard of platelet transfusion in developed countries. It has been demonstrated that a significant transfusion risk remains, in particular with older platelet concentrates (PCs). In 2009, the shelf life of PCs was therefore reduced in Germany to 4 days after the day of production according to Vote 38. The aim of the present study was the application and implementation of a recently developed flow cytometry-based rapid screening method (BactiFlow) for bacterial contamination at the end of PC shelf life as a routine in-process control. A total of 472 apheresis-derived PCs were tested using the BactiFlow flow cytometric assay to detect and count bacteria based on esterase activity in viable bacterial cells, while the BacT/Alert automated culture system served as the reference method. The automation potential of the flow cytometric assay was analysed by applying the semi-automated BactiFlow ALS system. An algorithm was developed for use in routine blood bank operations to extend the storage period of PCs. Two of the 472 apheresis PCs tested were positive in culture and identified as Propionibacterium species. One PC was positive for Staphylococcus aureus by both methods. All remaining specimens were tested negative by both methods. Our study demonstrates that routine bacterial testing of PCs was successfully implemented and the established algorithm proved efficient. The BactiFlow flow cytometric assay is the first rapid screening method which is suitable for a routine application combined with a high sensitivity. © 2011 The Authors. Transfusion Medicine © 2011 British Blood Transfusion Society.

  4. Differences in levels of platelet-derived microparticles in platelet components prepared using the platelet rich plasma, buffy coat, and apheresis procedures.

    PubMed

    Noulsri, Egarit; Udomwinijsilp, Prapaporn; Lerdwana, Surada; Chongkolwatana, Viroje; Permpikul, Parichart

    2017-04-01

    There has been an increased interest in platelet-derived microparticles (PMPs) in transfusion medicine. Little is known about PMP status during the preparation of platelet concentrates for transfusion. The aim of this study is to compare the PMP levels in platelet components prepared using the buffy coat (BC), platelet-rich plasma platelet concentrate (PRP-PC), and apheresis (AP) processes. Platelet components were prepared using the PRP-PC and BC processes. Apheresis platelets were prepared using the Trima Accel and Amicus instruments. The samples were incubated with annexin A5-FITC, CD41-PE, and CD62P-APC. At day 1 after processing, the PMPs and activated platelets were determined using flow cytometry. Both the percentage and number of PMPs were higher in platelet components prepared using the Amicus instrument (2.6±1.8, 32802±19036 particles/μL) than in platelet components prepared using the Trima Accel instrument (0.5±0.4, 7568±5298 particles/μL), BC (1.2±0.6, 12,920±6426 particles/μL), and PRP-PC (0.9±0.6, 10731±5514 particles/μL). Both the percentage and number of activated platelets were higher in platelet components prepared using the Amicus instrument (33.2±13.9, 427553±196965 cells/μL) than in platelet components prepared using the Trima Accel instrument (16.2±6.1, 211209±87706 cells/μL), BC (12.9±3.2, 140624±41003 cells/μL), and PRP-PC (21.1±6.3, 265210±86257 cells/μL). The study suggests high variability of PMPs and activated platelets in platelet components prepared using different processes. This result may be important in validating the instruments involved in platelet blood collection and processing. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Relationship between Platelet PPARs, cAMP Levels, and P-Selectin Expression: Antiplatelet Activity of Natural Products.

    PubMed

    Fuentes, Eduardo; Palomo, Iván

    2013-01-01

    Platelets are no longer considered simply as cells participating in thrombosis. In atherosclerosis, platelets are regulators of multiple processes, with the recruitment of inflammatory cells towards the lesion sites, inflammatory mediators release, and regulation of endothelial function. The antiplatelet therapy has been used for a long time in an effort to prevent and treat cardiovascular diseases. However, limited efficacy in some patients, drug resistance, and side effects are limitations of current antiplatelet therapy. In this context, a large number of natural products (polyphenols, terpenoids, alkaloids, and fatty acids) have been reported with antiplatelet activity. In this sense, the present paper describes mechanisms of antiplatelet action of natural products on platelet P-selectin expression through cAMP levels and its role as peroxisome proliferator-activated receptors agonists.

  6. Maintenance of platelet in vitro properties during 7-day storage in M-sol with a 30-hour interruption of agitation.

    PubMed

    Wagner, Stephen J; Myrup, Andrew; Awatefe, Helen; Thompson-Montgomery, Dedeene; Hirayama, Junichi; Skripchenko, Andrey

    2008-12-01

    Extensive periods without agitation can occasionally occur during platelet (PLT) shipment and can affect PLT quality during 5- to 7-day storage. The use of buffer-containing PLT additive solutions (ASs) may better preserve PLT quality during storage by maintaining PLT pH and other in vitro variables. A newly described bicarbonate-containing AS, M-sol, was compared to plasma for preservation of whole blood-derived PLT concentrates in which a 30-hour interruption of agitation was included. ABO-identical PLT-rich plasma intermediate products were pooled in sets of four, split, and centrifuged with subsequent plasma expression (n = 12). Two units were resuspended with M-sol AS to produce a 70 percent solution/30 percent plasma PLT concentrate; 2 units were resuspended in 100 percent plasma. One M-sol resuspended unit and 1 plasma unit were held on a laboratory bench in a standard shipping box for 30 hours between Day 2 and Day 3, while the other M-sol and plasma unit were continuously agitated. Standard in vitro testing for PLT quality variables on each set of 4 units was performed during storage (n = 12). Interrupting agitation of PLTs suspended in M-sol resulted in less of a pH decrement during storage than that of PLTs suspended in 100 percent plasma. On Days 5 and 7, the pH differences between M-sol and plasma units were 0.56 and 0.75 pH units, respectively (p < 0.0003). In addition, PLTs suspended in M-sol and subjected to an interruption of agitation had lesser Day 7 CD62+ cells, glucose utilization, and lactate production and greater hypotonic stress response, morphology, swirling, and aggregation response than those suspended in plasma (p storage than those of matched units suspended in plasma.

  7. Mean platelet volume: a potential biomarker of the risk and prognosis of heart disease.

    PubMed

    Choi, Dong-Hyun; Kang, Seong-Ho; Song, Heesang

    2016-11-01

    Platelets are essential for progression of atherosclerotic lesions, plaque destabilization, and thrombosis. They secrete and express many substances that are crucial mediators of coagulation, inflammation, and atherosclerosis. Mean platelet volume (MPV) is a precise measure of platelet size, and is routinely reported during complete blood count analysis. Emerging evidence supports the use of MPV as a biomarker predicting the risk of ischemic stroke in patients with atrial fibrillation, and as a guide for prescription of anticoagulation and rhythm-control therapy. In addition, MPV may predict the clinical outcome of percutaneous coronary intervention (PCI) in patients with coronary artery disease and indicate whether additional adjunctive therapy is needed to improve clinical outcomes. This review focuses on the current evidence that MPV may be a biomarker of the risk and prognosis of common heart diseases, particularly atrial fibrillation and coronary artery disease treated via PCI.

  8. Platelets generated from human embryonic stem cells are functional in vitro and in the microcirculation of living mice

    PubMed Central

    Lu, Shi-Jiang; Li, Feng; Yin, Hong; Feng, Qiang; Kimbrel, Erin A; Hahm, Eunsil; Thon, Jonathan N; Wang, Wei; Italiano, Joseph E; Cho, Jaehyung; Lanza, Robert

    2011-01-01

    Platelets play an essential role in hemostasis and atherothrombosis. Owing to their short storage time, there is constant demand for this life-saving blood component. In this study, we report that it is feasible to generate functional megakaryocytes and platelets from human embryonic stem cells (hESCs) on a large scale. Differential-interference contrast and electron microscopy analyses showed that ultrastructural and morphological features of hESC-derived platelets were indistinguishable from those of normal blood platelets. In functional assays, hESC-derived platelets responded to thrombin stimulation, formed microaggregates, and facilitated clot formation/retraction in vitro. Live cell microscopy demonstrated that hESC-platelets formed lamellipodia and filopodia in response to thrombin activation, and tethered to each other as observed in normal blood. Using real-time intravital imaging with high-speed video microscopy, we have also shown that hESC-derived platelets contribute to developing thrombi at sites of laser-induced vascular injury in mice, providing the first evidence for in vivo functionality of hESC-derived platelets. These results represent an important step toward generating an unlimited supply of platelets for transfusion. Since platelets contain no genetic material, they are ideal candidates for early clinical translation involving human pluripotent stem cells. PMID:21221130

  9. Platelet collection efficiencies of three different platelet-rich plasma preparation systems.

    PubMed

    Aydin, Fatma; Pancar Yuksel, Esra; Albayrak, Davut

    2015-06-01

    Different systems have been used for the preparation of platelet-rich plasma (PRP), but platelet collection efficiencies of these systems are not clear. To evaluate the platelet collection efficiencies of three different PRP preparation systems. Blood samples were obtained from the same 16 volunteers for each system. The samples were centrifuged and PRP was prepared by three systems. The ratio of the total number of platelets in PRP to the total number of platelets of the venous blood sample of the patient expressed in percentage was named as platelet collection efficiency and calculated for each system. Mean platelet collection efficiencies were 66.6 (min: 56.9, max: 76.9), 58.3 (min: 27.3, max: 102.8), 50.8 (min: 27.2, max: 73) for top and bottom bag system, system using citrated tube, and the system using tube with Ficoll and cell extraction kit, respectively. Statistically significant difference was found only between the platelet collection efficiencies of systems using the tube with ficoll and cell extraction kit and the top and bottom bag system (p = 0.002). All three systems could be used for PRP preparation, but top and bottom bag system offers a slight advantage over the system using Ficoll and cell extraction kit regarding the platelet collection efficiency.

  10. Preservation of Biological Activity of Plasma and Platelet-Derived Eye Drops After Their Different Time and Temperature Conditions of Storage.

    PubMed

    Anitua, Eduardo; de la Fuente, María; Riestra, Ana; Merayo-Lloves, Jesús; Muruzábal, Francisco; Orive, Gorka

    2015-09-01

    To analyze whether plasma rich in growth factors (PRGF) eye drops preserve their biological characteristics and activity after storage for 3 and 6 months at -20°C, at 4°C, and at room temperature for 72 hours, compared with fresh samples (t0). Blood from 6 healthy donors was harvested and centrifuged to obtain PRGF free of leukocytes. Resulting PRGF eye drops were stored for 3 and 6 months at -20°C. At each time, 2 aliquots were maintained at room temperature or at 4°C for 72 hours. Platelet-derived growth factor-AB, transforming growth factor-β1, vascular endothelial growth factor, epidermal growth factor, insulin-like growth factor-1, angiopoietin-1, and thrombospondin-1 were quantified at each time and temperature of storage. Also, the effect of PRGF eye drops on proliferation of primary human keratocytes was evaluated. All the analyzed growth factor levels remained constant at each time and storage condition. No differences were observed in the proliferative activity of keratocytes after treatment with PRGF eye drops at any studied time or temperature. Finally, there was no microbial contamination in any of the PRGF eye drops. The preservation of the PRGF eye drops at -20°C for up to 3 and 6 months does not mean reduction of the main growth factors and proteins implicated in ocular surface wound healing. Eye drop characteristics and in vitro biological activity were not affected by their usage and conservation for 72 hours at 4°C or at room temperature.

  11. Acute effects of 30 minutes of exposure to a smartphone call on in vitro platelet function

    PubMed Central

    Lippi, Giuseppe; Danese, Elisa; Brocco, Giorgio; Gelati, Matteo; Salvagno, Gian Luca; Montagnana, Martina

    2017-01-01

    Background Significant concerns are now regularly raised about the safety of excessive mobile phone use. This study was aimed to assess the acute effects of radiofrequency waves emitted by a commercial smartphone on platelet function. Materials and methods Two sequential citrated blood samples were collected from 16 healthy volunteers recruited from laboratory staff. The first sample was placed in a plastic rack, 1 cm distant from a commercial smartphone receiving a 30-min call and emitting 900 MHz radiofrequency waves. The second sample was placed in another plastic rack, isolated from radiofrequency wave sources, for the same period. The platelet count and the mean platelet volume were then assessed in all blood samples, whereas platelet function was evaluated using the platelet function analyser-100 (PFA-100). Results A 30-min exposure of citrated blood to smartphone radiofrequency waves induced significant prolongation of collagen-epinephrine aggregation (median increase, 10%) and a considerable increase of mean platelet volume (median increase, 5%), whereas collagen-adenosine diphosphate aggregation and platelet count remained unchanged. Discussion This study demonstrates that smartphone radiofrequency waves induce significant perturbation of platelet structure and function, thus providing further support to concerns regarding excessive use of mobile phones. Caution should also be taken with regards to blood products containing platelets, which should be kept far away from mobile phones and smartphones throughout the production pipeline and storage period. PMID:27177410

  12. Acute effects of 30 minutes of exposure to a smartphone call on in vitro platelet function.

    PubMed

    Lippi, Giuseppe; Danese, Elisa; Brocco, Giorgio; Gelati, Matteo; Salvagno, Gian Luca; Montagnana, Martina

    2017-05-01

    Significant concerns are now regularly raised about the safety of excessive mobile phone use. This study was aimed to assess the acute effects of radiofrequency waves emitted by a commercial smartphone on platelet function. Two sequential citrated blood samples were collected from 16 healthy volunteers recruited from laboratory staff. The first sample was placed in a plastic rack, 1 cm distant from a commercial smartphone receiving a 30-min call and emitting 900 MHz radiofrequency waves. The second sample was placed in another plastic rack, isolated from radiofrequency wave sources, for the same period. The platelet count and the mean platelet volume were then assessed in all blood samples, whereas platelet function was evaluated using the platelet function analyser-100 (PFA-100). A 30-min exposure of citrated blood to smartphone radiofrequency waves induced significant prolongation of collagen-epinephrine aggregation (median increase, 10%) and a considerable increase of mean platelet volume (median increase, 5%), whereas collagen-adenosine diphosphate aggregation and platelet count remained unchanged. This study demonstrates that smartphone radiofrequency waves induce significant perturbation of platelet structure and function, thus providing further support to concerns regarding excessive use of mobile phones. Caution should also be taken with regards to blood products containing platelets, which should be kept far away from mobile phones and smartphones throughout the production pipeline and storage period.

  13. LDL oxidation by platelets propagates platelet activation via an oxidative stress-mediated mechanism.

    PubMed

    Carnevale, Roberto; Bartimoccia, Simona; Nocella, Cristina; Di Santo, Serena; Loffredo, Lorenzo; Illuminati, Giulio; Lombardi, Elisabetta; Boz, Valentina; Del Ben, Maria; De Marco, Luigi; Pignatelli, Pasquale; Violi, Francesco

    2014-11-01

    Platelets generate oxidized LDL (ox-LDL) via NOX2-derived oxidative stress. We investigated if once generated by activated platelets ox-LDL can propagate platelet activation. Experiments were performed in platelets from healthy subjects (HS), hyper-cholesterolemic patients and patients with NOX2 hereditary deficiency. Agonist-stimulated platelets from HS added with LDL were associated with a dose-dependent increase of reactive oxidant species and ox-LDL. Agonist-stimulated platelets from HS added with a fixed dose of LDL (57.14 μmol/L) or added with homogenized human atherosclerotic plaque showed enhanced ox-LDL formation (approximately +50% and +30% respectively), which was lowered by a NOX2 inhibitor (approximately -35% and -25% respectively). Compared to HS, ox-LDL production was more pronounced in agonist-stimulated platelet rich plasma (PRP) from hyper-cholesterolemic patients but was almost absent in PRP from NOX2-deficient patients. Platelet aggregation and 8-iso-PGF2α-ΙΙΙ formation increased in LDL-treated washed platelets (+42% and +53% respectively) and PRP (+31% and +53% respectively). Also, LDL enhanced platelet-dependent thrombosis at arterial shear rate (+33%) but did not affect platelet activation in NOX2-deficient patients. Platelet activation by LDL was significantly inhibited by CD36 or LOX1 blocking peptides, two ox-LDL receptor antagonists, or by a NOX2 inhibitor. LDL-added platelets showed increased p38MAPK (+59%) and PKC (+51%) phosphorylation, p47(phox) translocation to platelet membrane (+34%) and NOX2 activation (+30%), which were inhibited by ox-LDL receptor antagonists. Platelets oxidize LDL, which in turn amplify platelet activation via specific ox-LDL receptors; both effects are mediated by NOX2 activation. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  14. Bacterial detection of platelets: current problems and possible resolutions.

    PubMed

    Blajchman, Morris A; Beckers, Erik A M; Dickmeiss, Ebbe; Lin, Lilly; Moore, Gillian; Muylle, Ludo

    2005-10-01

    The greatest transfusion-transmitted disease risk facing a transfusion recipient is that of bacterial sepsis. The prevalence of bacterial contamination in platelets and red blood cells is approximately 1 in 3,000 units transfused. The available data indicate that transfusion-associated sepsis develops after 1 in 25,000 platelet transfusions and 1 in 250,000 red blood cell transfusions. One of the most widely used strategies for decreasing bacterial sepsis risk is bacterial detection. A roundtable meeting of experts was convened during the XXVIII Annual Congress of the International Society of Blood Transfusion (Edinburgh, UK, July 2004) to provide a forum for experts to share their experiences in the routine bacterial detection of platelet products. This article summarizes the presentations, discussions, and recommendations of the panel. The data presented indicate that some of the current bacterial screening technology is useful for blocking the issuance of platelet units that contain relatively high levels of contaminating bacteria. Platelet units are usually released based on a test-negative status, which often become test-positive only upon longer storage. These data thus suggest that bacterial screening may not prevent all transfusion-transmitted bacterial infections. Two transfusion-transmitted case reports further highlighted the limitation of the routine bacterial screening of platelet products. It was felt that newer technologies, such as pathogen inactivation, may represent a more reliable process, with a higher level of safety. The panel thus recommended that the Transfusion Medicine community may need to change its thinking (paradigm) about bacterial detection, toward the possibility of the pathogen inactivation of blood products, to deal with the bacterial contamination issue. It was suggested, where permitted by regulatory agencies, that blood centers should consider adopting first-generation pathogen inactivation systems as a more effective approach

  15. Insights into abnormal hemostasis in the Quebec platelet disorder from analyses of clot lysis.

    PubMed

    Diamandis, M; Adam, F; Kahr, W H A; Wang, P; Chorneyko, K A; Arsenault, A L; Rivard, G E; Hayward, C P M

    2006-05-01

    The Quebec platelet disorder (QPD) is inherited and characterized by delayed-onset bleeding following hemostatic challenge. Other characteristics include increased expression and storage of active urokinase-type plasminogen activator (u-PA) in platelets in the setting of normal to increased u-PA in plasma. There is also consumption of platelet plasminogen activator inhibitor-1 and increased generation of plasmin in platelets accompanied by proteolysis of stored alpha-granule proteins, including Factor V. Although fibrinolysis has been proposed to contribute to QPD bleeding, the effects of QPD blood and platelets on clot lysis have not been evaluated. We used thromboelastography (TEG), biochemical evaluations of whole blood clot lysis, assessments of clot ultrastructure, and perfusion of blood over preformed fibrin to gain insights into the disturbed hemostasis in the QPD. Thromboelastography was not sensitive to the increased u-PA in QPD blood. However, there was abnormal plasmin generation in QPD whole blood clots, generated at low shear, with biochemical evidence of increased fibrinolysis. The incorporation of QPD platelets into a forming clot led to progressive disruption of fibrin and platelet aggregates unless drugs were added to inhibit plasmin. In whole blood perfusion studies, QPD platelets showed normal adherence to fibrin, but their adhesion was followed by accelerated fibrinolysis. The QPD is associated with "gain-of-function" abnormalities that increase the lysis of forming or preformed clots. These findings suggest accelerated fibrinolysis is an important contributor to QPD bleeding.

  16. NOD2 Receptor is Expressed in Platelets and Enhances Platelet Activation and Thrombosis

    PubMed Central

    Zhang, Si; Zhang, Shenghui; Hu, Liang; Zhai, Lili; Xue, Ruyi; Ye, Jianqin; Chen, Leilei; Cheng, Guanjun; Mruk, Jozef; Kunapuli, Satya P.; Ding, Zhongren

    2015-01-01

    Background Pattern recognition receptor NOD2 (nucleotide binding oligomerization domain 2) is well investigated in immunity, its expression and function in platelets has never been explored. Method and Results Using RT-PCR and Western blot we show that both human and mouse platelets express NOD2, and its agonist MDP induced NOD2 activation as evidenced by receptor dimerization. NOD2 activation potentiates platelet aggregation and secretion induced by low concentration of thrombin or collagen, as well as clot retraction. These potentiating effects of MDP were not seen in platelets from NOD2-deficient mice. Plasma from septic patients also potentiates platelet aggregation induced by thrombin or collagen NOD2-dependently. Using intravital microscopy, we found that MDP administration accelerated in vivo thrombosis in FeCl3-injured mesenteric arteriole thrombosis mouse model. Platelet depletion and transfusion experiments confirmed that NOD2 from platelets contributes to the in vivo thrombosis in mice. NOD2 activation also accelerates platelet-dependent hemostasis. We further found that platelets express RIP2 (receptor-interacting protein 2), and provided evidences suggesting that MAPK and NO/sGC/cGMP/PGK pathways downstream of RIP2 mediate the role of NOD2 in platelets. Finally, MDP stimulates proinflammatory cytokine IL-1β maturation and accumulation in human and mouse platelets NOD2-dependently. Conclusions NOD2 is expressed in platelets and functions in platelet activation and arterial thrombosis, possibly during infection. To our knowledge, this is the first study on NOD-like receptors in platelets which links thrombotic events to inflammation. PMID:25825396

  17. Phosphatidylserine-mediated platelet clearance by endothelium decreases platelet aggregates and procoagulant activity in sepsis.

    PubMed

    Ma, Ruishuang; Xie, Rui; Yu, Chengyuan; Si, Yu; Wu, Xiaoming; Zhao, Lu; Yao, Zhipeng; Fang, Shaohong; Chen, He; Novakovic, Valerie; Gao, Chunyan; Kou, Junjie; Bi, Yayan; Thatte, Hemant S; Yu, Bo; Yang, Shufen; Zhou, Jin; Shi, Jialan

    2017-07-10

    The mechanisms that eliminate activated platelets in inflammation-induced disseminated intravascular coagulation (DIC) in micro-capillary circulation are poorly understood. This study explored an alternate pathway for platelet disposal mediated by endothelial cells (ECs) through phosphatidylserine (PS) and examined the effect of platelet clearance on procoagulant activity (PCA) in sepsis. Platelets in septic patients demonstrated increased levels of surface activation markers and apoptotic vesicle formation, and also formed aggregates with leukocytes. Activated platelets adhered were and ultimately digested by ECs in vivo and in vitro. Blocking PS on platelets or αvβ3 integrin on ECs attenuated platelet clearance resulting in increased platelet count in a mouse model of sepsis. Furthermore, platelet removal by ECs resulted in a corresponding decrease in platelet-leukocyte complex formation and markedly reduced generation of factor Xa and thrombin on platelets. Pretreatment with lactadherin significantly increased phagocytosis of platelets by approximately 2-fold, diminished PCA by 70%, prolonged coagulation time, and attenuated fibrin formation by 50%. Our results suggest that PS-mediated clearance of activated platelets by the endothelium results in an anti-inflammatory, anticoagulant, and antithrombotic effect that contribute to maintaining platelet homeostasis during acute inflammation. These results suggest a new therapeutic target for impeding the development of DIC.

  18. Handling and storage of human body fluids for analysis of extracellular vesicles

    PubMed Central

    Yuana, Yuana; Böing, Anita N.; Grootemaat, Anita E.; van der Pol, Edwin; Hau, Chi M.; Cizmar, Petr; Buhr, Egbert; Sturk, Auguste; Nieuwland, Rienk

    2015-01-01

    Because procedures of handling and storage of body fluids affect numbers and composition of extracellular vesicles (EVs), standardization is important to ensure reliable and comparable measurements of EVs in a clinical environment. We aimed to develop standard protocols for handling and storage of human body fluids for EV analysis. Conditions such as centrifugation, single freeze–thaw cycle, effect of time delay between blood collection and plasma preparation and storage were investigated. Plasma is the most commonly studied body fluid in EV research. We mainly focused on EVs originating from platelets and erythrocytes and investigated the behaviour of these 2 types of EVs independently as well as in plasma samples of healthy subjects. EVs in urine and saliva were also studied for comparison. All samples were analysed simultaneously before and after freeze–thawing by resistive pulse sensing, nanoparticle tracking analysis, conventional flow cytometry (FCM) and transmission (scanning) electron microscopy. Our main finding is that the effect of centrifugation markedly depends on the cellular origin of EVs. Whereas erythrocyte EVs remain present as single EVs after centrifugation, platelet EVs form aggregates, which affect their measured concentration in plasma. Single erythrocyte and platelet EVs are present mainly in the range of 100–200 nm, far below the lower limit of what can be measured by conventional FCM. Furthermore, the effects of single freeze–thaw cycle, time delay between blood collection and plasma preparation up to 1 hour and storage up to 1 year are insignificant (p>0.05) on the measured concentration and diameter of EVs from erythrocyte and platelet concentrates and EVs in plasma, urine and saliva. In conclusion, in standard protocols for EV studies, centrifugation to isolate EVs from collected body fluids should be avoided. Freezing and storage of collected body fluids, albeit their insignificant effects, should be performed identically for

  19. Handling and storage of human body fluids for analysis of extracellular vesicles.

    PubMed

    Yuana, Yuana; Böing, Anita N; Grootemaat, Anita E; van der Pol, Edwin; Hau, Chi M; Cizmar, Petr; Buhr, Egbert; Sturk, Auguste; Nieuwland, Rienk

    2015-01-01

    Because procedures of handling and storage of body fluids affect numbers and composition of extracellular vesicles (EVs), standardization is important to ensure reliable and comparable measurements of EVs in a clinical environment. We aimed to develop standard protocols for handling and storage of human body fluids for EV analysis. Conditions such as centrifugation, single freeze-thaw cycle, effect of time delay between blood collection and plasma preparation and storage were investigated. Plasma is the most commonly studied body fluid in EV research. We mainly focused on EVs originating from platelets and erythrocytes and investigated the behaviour of these 2 types of EVs independently as well as in plasma samples of healthy subjects. EVs in urine and saliva were also studied for comparison. All samples were analysed simultaneously before and after freeze-thawing by resistive pulse sensing, nanoparticle tracking analysis, conventional flow cytometry (FCM) and transmission (scanning) electron microscopy. Our main finding is that the effect of centrifugation markedly depends on the cellular origin of EVs. Whereas erythrocyte EVs remain present as single EVs after centrifugation, platelet EVs form aggregates, which affect their measured concentration in plasma. Single erythrocyte and platelet EVs are present mainly in the range of 100-200 nm, far below the lower limit of what can be measured by conventional FCM. Furthermore, the effects of single freeze-thaw cycle, time delay between blood collection and plasma preparation up to 1 hour and storage up to 1 year are insignificant (p>0.05) on the measured concentration and diameter of EVs from erythrocyte and platelet concentrates and EVs in plasma, urine and saliva. In conclusion, in standard protocols for EV studies, centrifugation to isolate EVs from collected body fluids should be avoided. Freezing and storage of collected body fluids, albeit their insignificant effects, should be performed identically for

  20. Platelet Counts in Insoluble Platelet-Rich Fibrin Clots: A Direct Method for Accurate Determination.

    PubMed

    Kitamura, Yutaka; Watanabe, Taisuke; Nakamura, Masayuki; Isobe, Kazushige; Kawabata, Hideo; Uematsu, Kohya; Okuda, Kazuhiro; Nakata, Koh; Tanaka, Takaaki; Kawase, Tomoyuki

    2018-01-01

    Platelet-rich fibrin (PRF) clots have been used in regenerative dentistry most often, with the assumption that growth factor levels are concentrated in proportion to the platelet concentration. Platelet counts in PRF are generally determined indirectly by platelet counting in other liquid fractions. This study shows a method for direct estimation of platelet counts in PRF. To validate this method by determination of the recovery rate, whole-blood samples were obtained with an anticoagulant from healthy donors, and platelet-rich plasma (PRP) fractions were clotted with CaCl 2 by centrifugation and digested with tissue-plasminogen activator. Platelet counts were estimated before clotting and after digestion using an automatic hemocytometer. The method was then tested on PRF clots. The quality of platelets was examined by scanning electron microscopy and flow cytometry. In PRP-derived fibrin matrices, the recovery rate of platelets and white blood cells was 91.6 and 74.6%, respectively, after 24 h of digestion. In PRF clots associated with small and large red thrombi, platelet counts were 92.6 and 67.2% of the respective total platelet counts. These findings suggest that our direct method is sufficient for estimating the number of platelets trapped in an insoluble fibrin matrix and for determining that platelets are distributed in PRF clots and red thrombi roughly in proportion to their individual volumes. Therefore, we propose this direct digestion method for more accurate estimation of platelet counts in most types of platelet-enriched fibrin matrix.

  1. Platelet Counts in Insoluble Platelet-Rich Fibrin Clots: A Direct Method for Accurate Determination

    PubMed Central

    Kitamura, Yutaka; Watanabe, Taisuke; Nakamura, Masayuki; Isobe, Kazushige; Kawabata, Hideo; Uematsu, Kohya; Okuda, Kazuhiro; Nakata, Koh; Tanaka, Takaaki; Kawase, Tomoyuki

    2018-01-01

    Platelet-rich fibrin (PRF) clots have been used in regenerative dentistry most often, with the assumption that growth factor levels are concentrated in proportion to the platelet concentration. Platelet counts in PRF are generally determined indirectly by platelet counting in other liquid fractions. This study shows a method for direct estimation of platelet counts in PRF. To validate this method by determination of the recovery rate, whole-blood samples were obtained with an anticoagulant from healthy donors, and platelet-rich plasma (PRP) fractions were clotted with CaCl2 by centrifugation and digested with tissue-plasminogen activator. Platelet counts were estimated before clotting and after digestion using an automatic hemocytometer. The method was then tested on PRF clots. The quality of platelets was examined by scanning electron microscopy and flow cytometry. In PRP-derived fibrin matrices, the recovery rate of platelets and white blood cells was 91.6 and 74.6%, respectively, after 24 h of digestion. In PRF clots associated with small and large red thrombi, platelet counts were 92.6 and 67.2% of the respective total platelet counts. These findings suggest that our direct method is sufficient for estimating the number of platelets trapped in an insoluble fibrin matrix and for determining that platelets are distributed in PRF clots and red thrombi roughly in proportion to their individual volumes. Therefore, we propose this direct digestion method for more accurate estimation of platelet counts in most types of platelet-enriched fibrin matrix. PMID:29450197

  2. EMMPRIN (CD147/basigin) mediates platelet-monocyte interactions in vivo and augments monocyte recruitment to the vascular wall.

    PubMed

    Schulz, C; von Brühl, M-L; Barocke, V; Cullen, P; Mayer, K; Okrojek, R; Steinhart, A; Ahmad, Z; Kremmer, E; Nieswandt, B; Frampton, J; Massberg, S; Schmidt, R

    2011-05-01

    Platelets play a central role in hemostasis, in inflammatory diseases such as atherosclerosis, and during thrombus formation following vascular injury. Thereby, platelets interact intensively with monocytes and enhance their recruitment to the vascular wall. To investigate the role of the extracellular matrix metalloproteinase inducer (EMMPRIN) in platelet-monocyte interactions. Isolated human monocytes were perfused in vitro over firmly adherent platelets to allow investigation of the role of EMMPRIN in platelet-monocyte interactions under flow conditions. Monocytes readily bound to surface-adherent platelets. Both antibody blockade and gene silencing of monocyte EMMPRIN substantially attenuated firm adhesion of monocytes to platelets at arterial and venous shear rates. In vivo, platelet interactions with the murine monocyte cell line ANA-1 were significantly decreased when ANA-1 cells were pretreated with EMMPRIN-silencing small interfering RNA prior to injection into wild-type mice. Using intravital microscopy, we showed that recruitment of EMMPRIN-silenced ANA-1 to the injured carotid artery was significantly reduced as compared with control cells. Further silencing of EMMPRIN resulted in significantly fewer ANA-1-platelet aggregates in the mouse circulation as determined by flow cytometry. Finally, we identified glycoprotein (GP)VI as a critical corresponding receptor on platelets that mediates interaction with monocyte EMMPRIN. Thus, blocking of GPVI inhibited the effect of EMMPRIN on firm monocyte adhesion to platelets under arterial flow conditions in vitro, and abrogated EMMPRIN-mediated platelet-monocyte aggregate formation in vivo. EMMPRIN supports platelet-monocyte interactions and promotes monocyte recruitment to the arterial wall. Therefore, EMMPRIN might represent a novel target to reduce vascular inflammation and atherosclerotic lesion development. © 2011 International Society on Thrombosis and Haemostasis.

  3. Platelets rich plasma versus minoxidil 5% in treatment of alopecia areata: A trichoscopic evaluation.

    PubMed

    El Taieb, Moustafa A; Ibrahim, Hassan; Nada, Essam A; Seif Al-Din, Mai

    2017-01-01

    Alopecia areata is a common cause of nonscarring alopecia that occurs in a patchy, confluent, or diffuse pattern. Dermoscopy is a noninvasive technique for the clinical diagnosis of many skin diseases. Topical minoxidil solution 5% and platelet rich plasma are important modalities used in treatment of alopecia areata. We aimed to evaluate the efficacy of PRP versus topical minoxidil 5% in the treatment of AA by clinical evaluation and trichoscopic examination. Ninety patients were allocated into three groups; the first was treated with topical minoxidil 5% solution, the second with platelets rich plasma injections, and the third with placebo. Diagnosis and follow up were done by serial digital camera photography of lesions and dermoscopic scan before and every 1 month after treatment for 3 months. Patients treated with minoxidil 5% and platelets rich plasma both have significant hair growth than placebo (p < .05). Patients treated with platelets rich plasma had an earlier response in the form of hair regrowth, reduction in short vellus hair and dystrophic hair unlike patients treated with minoxidil and control (p < .05). In conclusion, platelets rich plasma is more effective in the treatment of alopecia areata than topical minoxidil 5% as evaluated by clinical and trichoscopic examination. © 2016 Wiley Periodicals, Inc.

  4. Effect of pacing-induced myocardial ischemia on platelet activation and fibrin formation in the coronary circulation.

    PubMed

    Nichols, A B; Gold, K D; Marcella, J J; Cannon, P J; Owen, J

    1987-07-01

    The effect of pacing-induced myocardial ischemia on platelet activation and fibrin formation was investigated in seven patients with severe proximal lesions of the left anterior descending coronary artery to determine if acute ischemia activates the coagulation system. Fibrin formation was assessed from plasma levels of fibrinopeptide A. Platelet activation was assessed by levels of platelet factor 4, beta-thromboglobulin and thromboxane B2. Plasma levels were measured before, during and after acute myocardial ischemia induced by rapid atrial pacing. Blood samples were collected from the ascending aorta and from the great cardiac vein through heparin-bonded catheters. The occurrence of anterior myocardial ischemia was established by electrocardiography and by myocardial lactate extraction. No significant transmyocardial gradients in the levels of fibrinopeptide A, platelet factor 4, beta-thromboglobulin or thromboxane B2 were found at rest, during ischemia or in the recovery period, and levels in the great cardiac vein did not change in response to ischemia. These data indicate that pacing-induced myocardial ischemia does not result in release of fibrinopeptide A, platelet factor 4, beta-thromboglobulin or thromboxane B2 into the coronary circulation, and imply that acute ischemia does not induce platelet activation or fibrin formation in the coronary circulation.

  5. Comparison of point-of-care methods for preparation of platelet concentrate (platelet-rich plasma).

    PubMed

    Weibrich, Gernot; Kleis, Wilfried K G; Streckbein, Philipp; Moergel, Maximilian; Hitzler, Walter E; Hafner, Gerd

    2012-01-01

    This study analyzed the concentrations of platelets and growth factors in platelet-rich plasma (PRP), which are likely to depend on the method used for its production. The cellular composition and growth factor content of platelet concentrates (platelet-rich plasma) produced by six different procedures were quantitatively analyzed and compared. Platelet and leukocyte counts were determined on an automatic cell counter, and analysis of growth factors was performed using enzyme-linked immunosorbent assay. The principal differences between the analyzed PRP production methods (blood bank method of intermittent flow centrifuge system/platelet apheresis and by the five point-of-care methods) and the resulting platelet concentrates were evaluated with regard to resulting platelet, leukocyte, and growth factor levels. The platelet counts in both whole blood and PRP were generally higher in women than in men; no differences were observed with regard to age. Statistical analysis of platelet-derived growth factor AB (PDGF-AB) and transforming growth factor β1 (TGF-β1) showed no differences with regard to age or gender. Platelet counts and TGF-β1 concentration correlated closely, as did platelet counts and PDGF-AB levels. There were only rare correlations between leukocyte counts and PDGF-AB levels, but comparison of leukocyte counts and PDGF-AB levels demonstrated certain parallel tendencies. TGF-β1 levels derive in substantial part from platelets and emphasize the role of leukocytes, in addition to that of platelets, as a source of growth factors in PRP. All methods of producing PRP showed high variability in platelet counts and growth factor levels. The highest growth factor levels were found in the PRP prepared using the Platelet Concentrate Collection System manufactured by Biomet 3i.

  6. Relationship between Platelet PPARs, cAMP Levels, and P-Selectin Expression: Antiplatelet Activity of Natural Products

    PubMed Central

    Fuentes, Eduardo; Palomo, Iván

    2013-01-01

    Platelets are no longer considered simply as cells participating in thrombosis. In atherosclerosis, platelets are regulators of multiple processes, with the recruitment of inflammatory cells towards the lesion sites, inflammatory mediators release, and regulation of endothelial function. The antiplatelet therapy has been used for a long time in an effort to prevent and treat cardiovascular diseases. However, limited efficacy in some patients, drug resistance, and side effects are limitations of current antiplatelet therapy. In this context, a large number of natural products (polyphenols, terpenoids, alkaloids, and fatty acids) have been reported with antiplatelet activity. In this sense, the present paper describes mechanisms of antiplatelet action of natural products on platelet P-selectin expression through cAMP levels and its role as peroxisome proliferator-activated receptors agonists. PMID:24324520

  7. [Adjusting Platelet Counts for Platelet Aggregation Tests].

    PubMed

    Ling, Li-Qin; Yang, Xin-Chun; Chen, Hao; Liu, Chao-Nan; Chen, Si; Jiang, Hong; Jin, Ya-Xiong; Zhou, Jing

    2018-03-01

    To explore a better method to adjust platelet counts for light transmission aggregometry (LTA). Blood samples from 36 healthy participants aged from 18 to 50 yr. were collected.Platelet-rich plasma (PRP) was diluted using platelet-poor plasma (PPP) and physiological saline (PS),respectively,in a ratio of 1.5,2,2.5 and 3 times. Platelet aggregation was induced by adenosine diphosphate (ADP),arachidonic acid (ARA),collagen (COL), epinephrine (EPI),or ristocetin (RIS). The maximal aggregation rates (MAs) of different approaches were compared. We also compared the MAs induced by RIS between PRP-obtained-PPP and whole blood-obtained-PPP (2 100× g, 5 min). Compared with the original PRP,the MAs induced by ADP,ARA,and EPI decreased in PPP-adjusted PRP (significant at 2-3 times dilution ratio, P <0.05),but not in PS-adjusted PRP ( P >0.05). The MA induced by RIS decreased in PS-adjusted PRP (significant at all dilution ratios, P <0.05),but not in PPP-adjusted PRP ( P >0.05). No changes in the MA induced by COL were found in PS-adjusted PRP and PPP-adjusted PRP ( P >0.05). Whole blood-obtained-PPP (2 100× g, 5 min) had the same MA induced by ristocetin compared with PRP-obtained-PPP ( P >0.05). PS is recommended for adjusting platelets counts for platelet aggregation induced by ADP,ARA,COL and EPI. Whole blood-obtained-PPP (2 100 × g, 5 min) is recommended for RIS-induced aggregation as a matter of convenience. Copyright© by Editorial Board of Journal of Sichuan University (Medical Science Edition).

  8. Comparison of ultrastructural and nanomechanical signature of platelets from acute myocardial infarction and platelet activation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Li, Aiqun; Chen, Jianwei; Liang, Zhi-Hong

    Acute myocardial infarction (AMI) initiation and progression follow complex molecular and structural changes in the nanoarchitecture of platelets. However, it remains poorly understood how the transformation from health to AMI alters the ultrastructural and biomechanical properties of platelets within the platelet activation microenvironment. Here, we show using an atomic force microscope (AFM) that platelet samples, including living human platelets from the healthy and AMI patient, activated platelets from collagen-stimulated model, show distinct ultrastructural imaging and stiffness profiles. Correlative morphology obtained on AMI platelets and collagen-activated platelets display distinct pseudopodia structure and nanoclusters on membrane. In contrast to normal platelets, AMImore » platelets have a stiffer distribution resulting from complicated pathogenesis, with a prominent high-stiffness peak representative of platelet activation using AFM-based force spectroscopy. Similar findings are seen in specific stages of platelet activation in collagen-stimulated model. Further evidence obtained from different force measurement region with activated platelets shows that platelet migration is correlated to the more elasticity of pseudopodia while high stiffness at the center region. Overall, ultrastructural and nanomechanical profiling by AFM provides quantitative indicators in the clinical diagnostics of AMI with mechanobiological significance.« less

  9. Administration of platelet concentrates suspended in bicarbonated Ringer's solution in children who had platelet transfusion reactions.

    PubMed

    Kobayashi, J; Yanagisawa, R; Ono, T; Tatsuzawa, Y; Tokutake, Y; Kubota, N; Hidaka, E; Sakashita, K; Kojima, S; Shimodaira, S; Nakamura, T

    2018-02-01

    Adverse reactions to platelet transfusions are a problem. Children with primary haematological and malignant diseases may experience allergic transfusion reactions (ATRs) to platelet concentrates (PCs), which can be prevented by giving washed PCs. A new platelet additive solution, using bicarbonated Ringer's solution and acid-citrate-dextrose formula A (BRS-A), may be better for platelet washing and storage, but clinical data are scarce. A retrospective cohort study for consecutive cases was performed between 2013 and 2017. For 24 months, we transfused washed PCs containing BRS-A to children with primary haematological and malignant diseases and previous adverse reactions. Patients transfused with conventional PCs (containing residual plasma) were assigned as controls, and results were compared in terms of frequency of ATRs, corrected count increment (CCI) and occurrence of bleeding. We also studied children transfused with PCs washed by a different system as historical controls. Thirty-two patients received 377 conventional PC transfusions. ATRs occurred in 12 (37·5%) patients from transfused with 18 (4·8%) bags. Thirteen patients, who experienced reactions to regular PCs in plasma, then received 119 transfusion bags of washed PCs containing BRS-A, and none had ATRs to washed PCs containing BRS-A. Before study period, six patients transfused 137 classical washed PCs with different platelet additive solution, under same indication, ATRs occurred in one (16·7%) patient from transfused with one (0·7%) bags. CCIs (24 h) in were lower with classical washed PCs (1·26 ± 0·54) compared to regular PCs in plasma (2·07 ± 0·76) (P < 0·001), but there was no difference between washed PCs containing BRS-A (2·14 ± 0·77) and regular PCs (2·21 ± 0·79) (P = 0·769), and we saw no post-transfusion bleeding. Washed PCs containing BRS-A appear to prevent ATRs without loss of transfusion efficacy in children with primary haematological and malignant

  10. Effect of Blood Shear Forces on Platelet Mediated Thrombosis Inside Arterial Stenosis.

    NASA Astrophysics Data System (ADS)

    Maalej, Nabil

    Shear induced activation of platelets plays a major role in the onset of thrombosis in atherosclerotic arteries. Blood hemodynamics and its effect on platelet kinetics has been studied mainly in in vitro and in ex vivo experiments. We designed new in vivo methods to study blood hemodynamic effects on platelet kinetics in canine stenosed carotid arteries. A carotid artery-jugular vein anastomotic shunt was produced. Intimal damage and controlled variations in the degree of stenosis were produced on the artery. An inflatable cuff was placed around the jugular vein to control vascular resistance. An electromagnetic flowmeter was used to measure blood flow. Doppler ultrasound crystals were used to measure the velocity profiles inside and distal to the stenosis. Stenosis geometry was obtained using digital subtraction angiography and quantitative arteriography. Using these measurements we calculated the wall shear stress using the finite difference solution of the Navier-Stokes equations. To study platelet kinetics, autologous platelets were labeled with Indium Oxine and injected IV. A collimated Nal gamma counter was placed over the stenosis to detect radio-labeled platelet accumulation as platelet mediated thrombi formed in the stenosis. The radioactive count rate increased in an inverse parallel fashion to the decline in flow rate during thrombus formation. The platelet accumulation increased with the increase of percent stenosis and was maximal at the narrow portion of the stenosis. Acute thrombus formation leading to arterial occlusion was only observed for stenosis higher than 70 +/- 5%. Platelet accumulation rate was not significant until the pressure gradient across the stenosis exceeded 40 +/- 10 mmHg. Totally occlusive thrombus formation was only observed for shear stresses greater than a critical value of 100 +/- 10 Pa. Beyond this critical value acute platelet thrombus formation increased exponentially with shear. Increased shear stresses were found to

  11. Clinical application of radiolabelled platelets

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kessler, C.

    1990-01-01

    This book presents papers on the clinical applications of radiolabelled platelets. The papers are grouped into six sections on platelet labelling techniques, radiolabelled platelets in cardiology, monitoring of antiplatelet therapy, platelet scintigraphy in stroke patients, platelet scintigraphy in angiology, and platelet scintigraphy in hematology and other clinical applications, including renal transplant rejection.

  12. Secreted Immunomodulatory Proteins of Staphylococcus aureus Activate Platelets and Induce Platelet Aggregation.

    PubMed

    Binsker, Ulrike; Palankar, Raghavendra; Wesche, Jan; Kohler, Thomas P; Prucha, Josephine; Burchhardt, Gerhard; Rohde, Manfred; Schmidt, Frank; Bröker, Barbara M; Mamat, Uwe; Pané-Farré, Jan; Graf, Anica; Ebner, Patrick; Greinacher, Andreas; Hammerschmidt, Sven

    2018-04-01

    Staphylococcus aureus can cause bloodstream infections associated with infective endocarditis (IE) and disseminated intravascular coagulopathy (DIC). Both complications involve platelets. In view of an increasing number of antibiotic-resistant strains, new approaches to control systemic S. aureus infection are gaining importance. Using a repertoire of 52 recombinant S. aureus proteins in flow cytometry-based platelet activation and aggregation assays, we identified, in addition to the extracellular adherence protein Eap, three secreted staphylococcal proteins as novel platelet activating proteins. Eap and the chemotaxis inhibitory protein of S. aureus (CHIPS), the formyl peptide receptor-like 1 inhibitory protein (FLIPr) and the major autolysin Atl induced P-selectin expression in washed platelets and platelet-rich plasma. Similarly, AtlA, CHIPS and Eap induced platelet aggregation in whole blood. Fluorescence microscopy illustrated that P-selectin expression is associated with calcium mobilization and re-organization of the platelet actin cytoskeleton. Characterization of the functionally active domains of the major autolysin AtlA and Eap indicates that the amidase domain of Atl and the tandem repeats 3 and 4 of Eap are crucial for platelet activation. These results provide new insights in S. aureus protein interactions with platelets and identify secreted proteins as potential treatment targets in case of antibiotic-resistant S. aureus infection. Schattauer GmbH Stuttgart.

  13. Platelet adhesion in hypertension: application of a novel assay of platelet adhesion.

    PubMed

    Nadar, Sunil K; Caine, Graham J; Blann, Andrew D; Lip, Gregory Y H

    2005-01-01

    The increased risk of thromboembolism in hypertension may be related to a prothrombotic or hypercoagulable state, with abnormalities in haemostasis and platelet function. To investigate the role of platelets in the pathogenesis of thrombosis in hypertension, we applied a novel new assay to detect and quantify the degree of platelet adhesion to a defined coagulation molecule. Platelet-rich plasma (PRP) and citrated plasma (CP) were obtained from 50 patients with hypertension (25 treated, and 25 untreated) and 30 healthy controls. A suspension of 2 x 10(7) platelets were incubated for one hour in microtitre plates pre-coated with 5mg/mL fibrinogen. The supernatant was carefully aspirated, lysed with 5% tween and stored at -70 degrees C as supernatant platelet lysate (SPL). The wells were carefully washed with saline and bound platelets lysed as before, and stored at -70 degrees C as bound-platelet lysate (BPL). Soluble P-selectin (sP-sel) was determined in CP, SPL and BPL by enzyme-linked immunosorbent assay (ELISA). Patients with hypertension (both treated and previously untreated) had increased platelet adhesion, as determined by increased lysate sP-sel (P=0.002) in BPL, with no change in SPL (P=0.5) compared to healthy controls. There was no significant difference between treated and previously untreated hypertensives. Platelets from patients with hypertension display increased adhesion to an important coagulation factor (fibrinogen). This may, in part, account for the increased risk of thrombosis seen in these patients.

  14. Mouse prenatal platelet-forming lineages share a core transcriptional program but divergent dependence on MPL.

    PubMed

    Potts, Kathryn S; Sargeant, Tobias J; Dawson, Caleb A; Josefsson, Emma C; Hilton, Douglas J; Alexander, Warren S; Taoudi, Samir

    2015-08-06

    The thrombopoietic environment of the neonate is established during prenatal life; therefore, a comprehensive understanding of platelet-forming cell development during embryogenesis is critical to understanding the etiology of early-onset thrombocytopenia. The recent discovery that the first platelet-forming cells of the conceptus are not megakaryocytes (MKs) but diploid platelet-forming cells (DPFCs) revealed a previously unappreciated complexity in thrombopoiesis. This raises important questions, including the following. When do conventional MKs appear? Do pathogenic genetic lesions of adult MKs affect DPFCs? What role does myeloproliferative leukemia virus (MPL), a key regulator of adult megakaryopoiesis, play in prenatal platelet-forming lineages? We performed a comprehensive study to determine the spatial and temporal appearance of prenatal platelet-forming lineages. We demonstrate that DPFCs originate in the yolk sac and then rapidly migrate to other extra- and intraembryonic tissues. Using gene disruption models of Gata1 and Nfe2, we demonstrate that perturbing essential adult MK genes causes an analogous phenotype in the early embryo before the onset of hematopoietic stem/progenitor cell-driven (definitive) hematopoiesis. Finally, we present the surprising finding that DPFC and MK commitment from their respective precursors is MPL independent in vivo but that completion of MK differentiation and establishment of the prenatal platelet mass is dependent on MPL expression. © 2015 by The American Society of Hematology.

  15. Platelet impedance adhesiometry: A novel technique for the measurement of platelet adhesion and spreading.

    PubMed

    Polgár, L; Soós, P; Lajkó, E; Láng, O; Merkely, B; Kőhidai, L

    2018-06-01

    Thrombogenesis plays an important role in today's morbidity and mortality. Antithrombotics are among the most frequently prescribed drugs. Thorough knowledge of platelet function is needed for optimal clinical care. Platelet adhesion is a separate subprocess of platelet thrombus formation; still, no well-standardized technique for the isolated measurement of platelet adhesion exists. Impedimetry is one of the most reliable, state-of-art techniques to analyze cell adhesion, proliferation, viability, and cytotoxicity. We propose impedimetry as a feasible novel method for the isolated measurement of 2 significant platelet functions: adhesion and spreading. Laboratory reference platelet agonists (epinephrine, ADP, and collagen) were applied to characterize platelet functions by impedimetry using the xCELLigence SP system. Platelet samples were obtained from 20 healthy patients under no drug therapy. Standard laboratory parameters and clinical patient history were also analyzed. Epinephrine and ADP increased platelet adhesion in a concentration-dependent manner, while collagen tended to have a negative effect. Serum sodium and calcium levels and age had a negative correlation with platelet adhesion induced by epinephrine and ADP, while increased immunoreactivity connected with allergic diseases was associated with increased platelet adhesion induced by epinephrine and ADP. ADP increased platelet spreading in a concentration-dependent manner. Impedimetry proved to be a useful and sensitive method for the qualitative and quantitated measurement of platelet adhesion, even differentiating between subgroups of a healthy population. This novel technique is offered as an important method in the further investigation of platelet function. © 2018 John Wiley & Sons Ltd.

  16. Classification of platelet concentrates: from pure platelet-rich plasma (P-PRP) to leucocyte- and platelet-rich fibrin (L-PRF).

    PubMed

    Dohan Ehrenfest, David M; Rasmusson, Lars; Albrektsson, Tomas

    2009-03-01

    The topical use of platelet concentrates is recent and its efficiency remains controversial. Several techniques for platelet concentrates are available; however, their applications have been confusing because each method leads to a different product with different biology and potential uses. Here, we present classification of the different platelet concentrates into four categories, depending on their leucocyte and fibrin content: pure platelet-rich plasma (P-PRP), such as cell separator PRP, Vivostat PRF or Anitua's PRGF; leucocyte- and platelet-rich plasma (L-PRP), such as Curasan, Regen, Plateltex, SmartPReP, PCCS, Magellan or GPS PRP; pure plaletet-rich fibrin (P-PRF), such as Fibrinet; and leucocyte- and platelet-rich fibrin (L-PRF), such as Choukroun's PRF. This classification should help to elucidate successes and failures that have occurred so far, as well as providing an objective approach for the further development of these techniques.

  17. Platelet-rich plasma and platelet gel preparation using Plateltex.

    PubMed

    Mazzucco, L; Balbo, V; Cattana, E; Borzini, P

    2008-04-01

    The platelet gel is made by embedding concentrate platelets within a semisolid (gel) network of polymerized fibrin. It is believed that this blood component will be used more and more in the treatment of several clinical conditions and as an adjunctive material in tissue engineering. Several systems are available to produce platelet-rich plasma (PRP) for topical therapy. Recently, a new system became commercially available, Plateltex. Here we report the technical performance of this system in comparison with the performance of other commercially available systems: PRGF, PRP-Landesber, Curasan, PCCS, Harvest, Vivostat, Regen and Fibrinet. Both the PRP and the gel were prepared according to the manufacturer's directions. The blood samples of 20 donors were used. The yield, the efficiency, and the amount of platelet-derived growth factor AB (PDGF-AB), transforming growth factor beta, vascular endothelial growth factor and fibroblast growth factor were measured in the resulting PRP. The feature of the batroxobin-induced gelation was evaluated. The yield, the collection efficiency and the growth factor content of Plateltex were comparable to those of most of the other available systems. The gelation time was not dependent on the fibrinogen concentration; however, it was strongly influenced by the contact surface area of the container where the clotting reaction took place (P < 0.0001). Plateltex provided platelet recovery, collection efficiency and PDGF-AB availability close to those provided by other systems marketed with the same intended use. Batroxobin, the enzyme provided to induce gelation, acts differently from thrombin, which is used by most other systems. Platelets treated with thrombin become activated; they release their growth factors quickly. Furthermore, thrombin-platelet interaction is a physiological mechanism that hastens the clot-retraction rate. On the contrary, platelets treated with batroxobin do not become activated; they are passively entrapped

  18. Mean Platelet Volume (MPV), Platelet Distribution Width (PDW), Platelet Count and Plateletcrit (PCT) as predictors of in-hospital paediatric mortality: a case-control Study.

    PubMed

    Golwala, Zainab Mohammedi; Shah, Hardik; Gupta, Neeraj; Sreenivas, V; Puliyel, Jacob M

    2016-06-01

    Thrombocytopenia has been shown to predict mortality. We hypothesize that platelet indices may be more useful prognostic indicators. Our study subjects were children one month to 14 years old admitted to our hospital. To determine whether platelet count, plateletcrit (PCT), mean platelet volume (MPV) and platelet distribution width (PDW) and their ratios can predict mortality in hospitalised children. Children who died during hospital stay were the cases. Controls were age matched children admitted contemporaneously. The first blood sample after admission was used for analysis. Receiver operating characteristic (ROC) curve was used to identify the best threshold for measured variables and the ratios studied. Multiple regression analysis was done to identify independent predictors of mortality. Forty cases and forty controls were studied. Platelet count, PCT and the ratios of MPV/Platelet count, MPV/PCT, PDW/Platelet count, PDW/PCT and MPV × PDW/Platelet count × PCT were significantly different among children who survived compared to those who died. On multiple regression analysis the ratio of MPV/PCT, PDW/Platelet count and MPV/Platelet count were risk factors for mortality with an odds ratio of 4.31(95% CI, 1.69-10.99), 3.86 (95% CI, 1.53-9.75), 3.45 (95% CI, 1.38-8.64) respectively. In 67% of the patients who died MPV/PCT ratio was above 41.8 and PDW/Platelet count was above 3.86. In 65% of patients who died MPV/Platelet count was above 3.45. The MPV/PCT, PDW/Platelet count and MPV/Platelet count, in the first sample after admission in this case control study were predictors of mortality and could predict 65% to 67% of deaths accurately.

  19. Early outgrowth cells versus endothelial colony forming cells functions in platelet aggregation.

    PubMed

    Bou Khzam, Lara; Bouchereau, Olivier; Boulahya, Rahma; Hachem, Ahmed; Zaid, Younes; Abou-Saleh, Haissam; Merhi, Yahye

    2015-11-09

    Endothelial progenitor cells (EPCs) have been implicated in neoangiogenesis, endothelial repair and cell-based therapies for cardiovascular diseases. We have previously shown that the recruitment of EPCs to sites of vascular lesions is facilitated by platelets where EPCs, in turn, modulate platelet function and thrombosis. However, EPCs encompass a heterogeneous population of progenitor cells that may exert different effects on platelet function. Recent evidence suggests the existence of two EPC subtypes: early outgrowth cells (EOCs) and endothelial colony-forming cells (ECFCs). We aimed at characterizing these two EPC subtypes and at identifying their role in platelet aggregation. EOCs and ECFCs were generated from human peripheral blood mononuclear cells (PBMCs) seeded in conditioned media on fibronectin and collagen, respectively. The morphological, phenotypical and functional characteristics of EOCs and ECFCs were assessed by optical and confocal laser scanning microscopes, cell surface markers expression, and Matrigel tube formation. The impact of EOCs and ECFCs on platelet aggregation was monitored in collagen-induced optical aggregometry and compared with PBMCs and human umbilical vein endothelial cells (HUVECs). The levels of the anti-platelet agents' nitric oxide (NO) and prostacyclin (PGI2) released from cultured cells as well as the expression of their respective producing enzymes NO synthases (NOS) and cyclooxygenases (COX) were also assessed. We showed that EOCs display a monocytic-like phenotype whereas ECFCs have an endothelial-like phenotype. We demonstrated that both EOCs and ECFCs and their supernatants inhibited platelet aggregation; however ECFCs were more efficient than EOCs. This could be related to the release of significantly higher amounts of NO and PGI2 from ECFCs, in comparison to EOCs. Indeed, ECFCs, like HUVECs, constitutively express the endothelial (eNOS)-and inducible (iNOS)-NOS isoforms, and COX-1 and weakly express COX-2, whereas

  20. Platelet ERK5 is a Redox Switch and Triggers Maladaptive Platelet Responses and Myocardial Infarct Expansion

    PubMed Central

    Cameron, Scott J.; Ture, Sara K.; Mickelsen, Deanne; Chakrabarti, Enakshi; Modjeski, Kristina L.; McNitt, Scott; Seaberry, Micheal; Field, David J.; Le, Nhat-Tu; Abe, Jun-ichi; Morrell, Craig N.

    2015-01-01

    Background Platelets have a pathophysiologic role in the ischemic microvascular environment of acute coronary syndromes (ACS). Compared to platelet activation in normal healthy conditions, less attention is given to mechanisms of platelet activation in diseased states. Platelet function and mechanisms of activation in ischemic and reactive oxygen species (ROS) rich environments may not be the same as in normal healthy conditions. Extracellular Regulated Protein Kinase 5 (ERK5) is a Mitogen Activated Protein Kinase (MAPK) family member activated in hypoxic, ROS rich environments, and in response to receptor signaling mechanisms. Prior studies suggest a protective effect of ERK5 in endothelial and myocardial cells following ischemia. We present evidence that platelets express ERK5 and platelet ERK5 has an adverse effect on platelet activation via selective receptor-dependent and receptor-independent ROS mediated mechanisms in ischemic myocardium. Methods and Results Using isolated human platelets and a mouse model of myocardial infarction (MI), we found that platelet ERK5 is activated post-MI and platelet specific ERK5−/− mice have less platelet activation, reduced MI size, and improved post-MI heart function. Furthermore, the expression of downstream ERK5 regulated proteins is reduced in ERK5−/− platelets post-MI. Conclusions ERK5 functions as a platelet activator in ischemic conditions and platelet ERK5 maintains the expression of some platelet proteins following MI, leading to infarct expansion. This demonstrates that platelet function in normal healthy conditions is different from platelet function in chronic ischemic and inflammatory conditions. Platelet ERK5 may be a target for acute therapeutic intervention in the thrombotic and inflammatory post-MI environment. PMID:25934838

  1. Antimicrobial effect of platelet-rich plasma and platelet-rich fibrin.

    PubMed

    Badade, Pallavi S; Mahale, Swapna A; Panjwani, Alisha A; Vaidya, Prutha D; Warang, Ayushya D

    2016-01-01

    Platelet concentrates have been extensively used in a variety of medical fields to promote soft- and hard-tissue regeneration. The significance behind their use lies in the abundance of growth factors (GFs) in platelets α-granules that promote wound healing. Other than releasing a pool of GFs upon activation, platelets also have many features that indicate their role in the anti-infective host defense. The aim of this study is to evaluate the antimicrobial activities of platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) against periodontal disease-associated bacteria. Blood samples were obtained from ten adult male patients. PRP and PRF were procured using centrifugation. The antimicrobial activity of PRP and PRF was evaluated by microbial culturing using bacterial strains of Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. P. gingivalis and A. actinomycetemcomitans were inhibited by PRP but not by PRF. PRP is a potentially useful substance in the fight against periodontal pathogens. This might represent a valuable property in adjunct to the enhancement of tissue regeneration.

  2. Comparative Effects of Platelet-Rich Plasma, Platelet Lysate, and Fetal Calf Serum on Mesenchymal Stem Cells.

    PubMed

    Lykov, A P; Bondarenko, N A; Surovtseva, M A; Kim, I I; Poveshchenko, O V; Pokushalov, E A; Konenkov, V I

    2017-10-01

    We studied the effects of human platelet-rich plasma and platelet lysate on proliferation, migration, and colony-forming properties of rat mesenchymal stem cells. Platelet-rich plasma and platelet lysate stimulated the proliferation, migration, and colony formation of mesenchymal stem cells. A real-time study showed that platelet-rich plasma produces the most potent stimulatory effect, while both platelet-rich plasma and platelet lysate stimulated migration of cells.

  3. Platelet receptor polymorphisms do not influence Staphylococcus aureus–platelet interactions or infective endocarditis

    PubMed Central

    Daga, Shruti; Shepherd, James G.; Callaghan, J. Garreth S.; Hung, Rachel K.Y.; Dawson, Dana K.; Padfield, Gareth J.; Hey, Shi Y.; Cartwright, Robyn A.; Newby, David E.; Fitzgerald, J. Ross

    2011-01-01

    Cardiac vegetations result from bacterium–platelet adherence, activation and aggregation, and are associated with increased morbidity and mortality in infective endocarditis. The GPIIb/IIIa and FcγRIIa platelet receptors play a central role in platelet adhesion, activation and aggregation induced by endocarditis pathogens such as Staphylococcus aureus, but the influence of known polymorphisms of these receptors on the pathogenesis of infective endocarditis is unknown. We determined the GPIIIa platelet antigen PlA1/A2 and FcγRIIa H131R genotype of healthy volunteers (n = 160) and patients with infective endocarditis (n = 40), and investigated the influence of these polymorphisms on clinical outcome in infective endocarditis and S. aureus–platelet interactions in vitro. Platelet receptor genotype did not correlate with development of infective endocarditis, vegetation characteristics on echocardiogram or the composite clinical end-point of embolism, heart failure, need for surgery or mortality (P > 0.05 for all), even though patients with the GPIIIa PlA1/A1 genotype had increased in vivo platelet activation (P = 0.001). Furthermore, neither GPIIIa PlA1/A2 nor FcγRIIa H131R genotype influenced S. aureus-induced platelet adhesion, activation or aggregation in vitro (P > 0.05). Taken together, our data suggest that the GPIIIa and FcγRIIa platelet receptor polymorphisms do not influence S. aureus–platelet interactions in vitro or the clinical course of infective endocarditis. PMID:21044892

  4. The Protective Effect of Poloxamer-188 on Platelet Functions.

    PubMed

    Guler, Nil; Abro, Schuharazad; Emanuele, Marty; Iqbal, Omer; Hoppensteadt, Debra; Fareed, Jawed

    2017-11-01

    Poloxamer-188 (MST-188) is effective in the repair/recovery of damaged cell membranes. MST-188 is a promising agent for protecting blood cell viability. The aim of the study is to test the hypothesis that MST-188 can extend the duration of platelet function. Blood samples were collected from 20 healthy volunteers. MST-188 (10 or 2 mg/mL) containing platelet-rich plasma (PRP) was prepared with 2 procedures. First, PRP prepared from MST-188 added whole blood (WB); second, MST-188 was added to PRP. These were referred to MST-188-WB preparation (WBP) and MST-188-PRP preparation (PRPP), respectively. For control, saline was used in the same manner. Agonist-induced aggregation (AIA) studies were performed at 30, 180, and 300 minutes using Platelet Aggregation Profiler (PAP-8) aggregometer (Bio/Data Corporation, Horsham, Pennsylvania) and Adenosine diphosphate (ADP), arachidonic acid, collagen, and epinephrine as agonists at final concentration of 20 µM, 500 µg/mL, 0.19 mg/mL, and 100 µM, respectively. There was a protective effect of MST-188 on ADP and collagen AIA. At 300 minutes, ADP AIA was found to be 50.2% higher than saline control in 2-mg WBP, 43% at 10-mg PRPP, and 10.4% at 2-mg PRPP. Protective effect of on collagen AIA was 65.9% in 2-mg WBP, 42.74% at 10-mg PRPP, and 11.42% at 2-mg PRPP. In comparison between 30 and 300 minutes, MST-188 showed significant protection in terms of ADP and collagen receptors and for both types of preparations (WBP and PRPP). The protective effects of MST-188 on ADP- and collagen-induced platelet aggregation may contribute to the preservation of platelet functionality upon storage in blood banks.

  5. How platelets safeguard vascular integrity

    PubMed Central

    Ho-Tin-Noé, Benoit; Demers, Mélanie; Wagner, Denisa D

    2011-01-01

    Summary The haemostatic role of platelets was established in the 1880s by Bizzozero who observed their ability to adhere and aggregate at sites of vascular injury. It was only some 80 years later that the function of platelets in maintaining the structural integrity of intact blood vessels was reported by Danielli. Danielli noted that platelets help preserve the barrier function of endothelium during organ perfusion. Subsequent studies have demonstrated further that platelets are continuously needed to support intact mature blood vessels. More recently, platelets were shown to safeguard developing vessels, lymphatics, as well as the microvasculature at sites of leukocyte infiltration, including inflamed organs and tumours. Interestingly, from a mechanistic point of view, the supporting role of platelets in these various vessels does not necessarily involve the well-understood process of platelet plug formation but, rather, may rely on secretion of the various platelet granules and their many active components. The present review focuses on these nonconventional aspects of platelet biology and function by presenting situations in which platelets intervene to maintain vascular integrity and discusses possible mechanisms of their actions. We propose that modulating these newly described platelet functions may help treat haemorrhage as well as treat cancer by increasing the efficacy of drug delivery to tumours. PMID:21781242

  6. Alternatives to allogeneic platelet transfusion.

    PubMed

    Desborough, Michael J R; Smethurst, Peter A; Estcourt, Lise J; Stanworth, Simon J

    2016-11-01

    Allogeneic platelet transfusions are widely used for the prevention and treatment of bleeding in thrombocytopenia. Recent evidence suggests platelet transfusions have limited efficacy and are associated with uncertain immunomodulatory risks and concerns about viral or bacterial transmission. Alternatives to transfusion are a well-recognised tenet of Patient Blood Management, but there has been less focus on different strategies to reduce bleeding risk by comparison to platelet transfusion. Direct alternatives to platelet transfusion include agents to stimulate endogenous platelet production (thrombopoietin mimetics), optimising platelet adhesion to endothelium by treating anaemia or increasing von Willebrand factor levels (desmopressin), increasing formation of cross-linked fibrinogen (activated recombinant factor VII, fibrinogen concentrate or recombinant factor XIII), decreasing fibrinolysis (tranexamic acid or epsilon aminocaproic acid) or using artificial or modified platelets (cryopreserved platelets, lyophilised platelets, haemostatic particles, liposomes, engineered nanoparticles or infusible platelet membranes). The evidence base to support the use of these alternatives is variable, but an area of active research. Much of the current randomised controlled trial focus is on evaluation of the use of thrombopoietin mimetics and anti-fibrinolytics. It is also recognised that one alternative strategy to platelet transfusion is choosing not to transfuse at all. © 2016 John Wiley & Sons Ltd.

  7. Normal platelet function in platelet concentrates requires non-platelet cells: a comparative in vitro evaluation of leucocyte-rich (type 1a) and leucocyte-poor (type 3b) platelet concentrates

    PubMed Central

    Parrish, William R; Roides, Breana; Hwang, Julia; Mafilios, Michael; Story, Brooks; Bhattacharyya, Samir

    2016-01-01

    Background Therapeutic success of platelet-rich plasma (PRP) may vary based on the composition and preparation method. The objective of this study was to evaluate the cellular components of platelet concentrates produced by a leucocyte-rich (LR-PRP) and a leucocyte-poor PRP systems (LP-PRP). Methods Parameters evaluated included platelet recovery, platelet concentration, red blood cell (RBC) and white blood cell (WBC) composition, platelet growth factor release and stimulation of human tendon cell proliferation in vitro. Results Platelet recoveries were 52% for LP-PRP and 89% for LR-PRP. LR-PRP demonstrated greater reproducibility with a 4.2% coefficient of variation (CV) compared with 19.4% for LP-PRP (p<0.001). LR-PRP demonstrated a greater increase in platelet concentration (7.9-fold) than LP-PRP (2.2-fold; p<0.001). LP-PRP showed 5.0-fold reductions in WBCs, while LR-PRP showed a 4.0-fold increase (p<0.001). LP-PRP reduced RBCs to a haematocrit of 0.25, while LR-PRP reduced haematocrit to 11.8. LP-PRP did not coagulate robustly on reactivation with CaCl2, and released significantly lower levels of epidermal growth factor (EGF) and transforming growth factor β1 (TGF-β1) than whole blood (p<0.03). LP-PRP also did not stimulate tendon cell proliferation greater than whole blood. In contrast, LR-PRP showed increases in each growth factor on activation with CaCl2 (p<0.01) and stimulated greater proliferation (p<0.05) compared with whole blood. Forced activation of LP-PRP with exogenous thrombin rescued the coagulation deficiency and induced greater growth factor release than comparable whole blood (p<0.03). Conclusions These data suggest that non-platelet cellular components in platelet concentrates are important for proper platelet function, including thrombin generation, growth factor release and clot retraction. PMID:27900155

  8. Normal platelet function in platelet concentrates requires non-platelet cells: a comparative in vitro evaluation of leucocyte-rich (type 1a) and leucocyte-poor (type 3b) platelet concentrates.

    PubMed

    Parrish, William R; Roides, Breana; Hwang, Julia; Mafilios, Michael; Story, Brooks; Bhattacharyya, Samir

    2016-01-01

    Therapeutic success of platelet-rich plasma (PRP) may vary based on the composition and preparation method. The objective of this study was to evaluate the cellular components of platelet concentrates produced by a leucocyte-rich (LR-PRP) and a leucocyte-poor PRP systems (LP-PRP). Parameters evaluated included platelet recovery, platelet concentration, red blood cell (RBC) and white blood cell (WBC) composition, platelet growth factor release and stimulation of human tendon cell proliferation in vitro. Platelet recoveries were 52% for LP-PRP and 89% for LR-PRP. LR-PRP demonstrated greater reproducibility with a 4.2% coefficient of variation (CV) compared with 19.4% for LP-PRP (p<0.001). LR-PRP demonstrated a greater increase in platelet concentration (7.9-fold) than LP-PRP (2.2-fold; p<0.001). LP-PRP showed 5.0-fold reductions in WBCs, while LR-PRP showed a 4.0-fold increase (p<0.001). LP-PRP reduced RBCs to a haematocrit of 0.25, while LR-PRP reduced haematocrit to 11.8. LP-PRP did not coagulate robustly on reactivation with CaCl 2 , and released significantly lower levels of epidermal growth factor (EGF) and transforming growth factor β1 (TGF-β1) than whole blood (p<0.03). LP-PRP also did not stimulate tendon cell proliferation greater than whole blood. In contrast, LR-PRP showed increases in each growth factor on activation with CaCl 2 (p<0.01) and stimulated greater proliferation (p<0.05) compared with whole blood. Forced activation of LP-PRP with exogenous thrombin rescued the coagulation deficiency and induced greater growth factor release than comparable whole blood (p<0.03). These data suggest that non-platelet cellular components in platelet concentrates are important for proper platelet function, including thrombin generation, growth factor release and clot retraction.

  9. Defining Platelet Function During Polytrauma

    DTIC Science & Technology

    2013-02-01

    calibrated automated thrombography, 3. Platelet-induced clot contraction and using viscoelastic measures such as TEG with Platelet Mapping™ and, 4. Flow...using calibrated automated thrombography (CAT). 3. Platelet-induced clot contraction and using viscoelastic measures such as TEG with Platelet Mapping...formation (such as Hemodyne’s platelet contractile force measurement and thromboelastrography). The degree to which certain injury patterns as well as

  10. Platelet lipidomics: a modern day perspective on lipid discovery and characterization in platelets

    PubMed Central

    O’Donnell, Valerie B; Murphy, Robert C.; Watson, Steve P

    2014-01-01

    Lipids are diverse families of biomolecules that perform essential structural and signaling roles in platelets. Their formation and metabolism is tightly controlled by enzymes and signal transduction pathways, and their dysregulation leads to significant defects in platelet function and disease. Platelet activation is associated with significant changes to membrane lipids, and formation of diverse bioactive lipids that play essential roles in hemostasis. In recent years, new generation mass spectrometry analysis of lipids (termed “lipidomics”) has begun to alter our understanding of how these molecules participate in key cellular processes. While, the application of lipidomics to platelet biology is still in its infancy, seminal earlier studies have shaped our knowledge of how lipids regulate key aspects of platelet biology, including aggregation, shape change, coagulation and degranulation, as well as how lipids generated by platelets influence other cells, such as leukocytes and the vascular wall, and thus how they regulate hemostasis, vascular integrity and inflammation, as well as contribute to pathologies including arterial/deep vein thrombosis and atherosclerosis. This review will provide a brief historical perspective on the characterization of lipids in platelets, then an overview of the new generation lipidomic approaches, their recent application to platelet biology, and future perspectives for research in this area. The major platelet-regulatory lipid families, their formation, metabolism, and their role in health and disease, will be summarized. PMID:24677238

  11. Short-term exposure of platelets to glucose impairs inhibition of platelet aggregation by cyclooxygenase inhibitors.

    PubMed

    Kobzar, Gennadi; Mardla, Vilja; Samel, Nigulas

    2011-01-01

    Aspirin treatment reduces cardiovascular events and deaths in high-risk non-diabetic patients, but not in patients suffering from diabetes. In these patients, hyperglycemia has been found to cause reduced platelet sensitivity to aspirin. It is supposed that long-term exposure of platelets to glucose leads to non-enzymatic glycosylation and impairs aspirin inhibition of platelet aggregation. On the other hand, short-term exposure of platelets to glucose also attenuates the effect of aspirin on platelets. The aim of the present work was to analyse the effect of short-term exposure of glucose on the inhibition of platelet aggregation by aspirin and other cyclooxygenase (COX) inhibitors. Already a 15 min exposure of platelets to glucose impaired aspirin inhibition of the platelet aggregation induced by collagen, thrombin, adenosine diphosphate (ADP), and arachidonic acid (AA). Aspirin inhibition of platelet aggregation in platelet-rich plasma (PRP) was attenuated by 5.6, 11.2, 16.8, and 22.4 mM of glucose in a concentration-dependent way. The same effect was observed with indomethacin and acetaminophen used as cyclooxygenase inhibitors instead of aspirin. N-methyl-L-arginine, an inhibitor of nitric oxide synthase, prevented the effect of glucose on aspirin, indomethacin and acetaminophen inhibition of platelet aggregation. Other monosaccharides, for example fructose and galactose, impaired aspirin inhibition as did glucose. Lactic acid (0.1, 0.2, 0.4, 0.8 mM), the end product of anaerobic glycolysis in platelets, impaired the inhibition of platelet aggregation with aspirin in a concentration-dependent way but did not affect indomethacin. It is suggested that lactic acid might be a mediator of the effect of glucose on aspirin inhibition in platelets.

  12. Evaluation of Plasma Platelet Microparticles in Thrombotic Thrombocytopenic Purpura.

    PubMed

    Tahmasbi, Leila; Karimi, Mehran; Kafiabadi, Sedigheh Amini; Nikougoftar, Mahin; Haghpanah, Sezaneh; Ranjbaran, Reza; Moghadam, Mohamad

    2017-01-01

    Platelet microparticles (PMPs) have a procoagulant activity about 50-100 times greater than active platelets due to high expression of negatively charged phospholipids on their surfaces. In this study, we evaluated microparticle immunophenotyping and also plasma PMPs level in patients with Thrombotic Thrombocytopenic Purpura (TTP) in Southern Iran. We had two study groups: 15 TTP patients and 15 healthy control group and PMPs from platelet concentrate (PC) at the 5 th day of storage. Microparticles were prepared in two steps, by low and high centrifugation followed by size confirmation via 'Dynamic Light Scattering (DLS)' Zetasizer. Immunophenotyping of PMPs was done via flow cytometry, using a FACS Calibur flow cytometer (BD, USA). PMPs counts were obtained using Partec-cyflow and Polysciences Microbeads (1 micron in diameter). Results were analyzed using FlowJo 7.6 (Treestar, USA) and Partec FlowMax software. Our results showed that the majority of microparticles in TTP patients and normal individuals were PMPs and also demonstrated that the plasma PMPs level in TTP patients was higher than the normal control group ( P -value<0.001). It seems that elevated PMPs level in TTP patients could be related to thrombotic events. Nevertheless, more studies are needed to confirm these results. © 2017 by the Association of Clinical Scientists, Inc.

  13. Effects of hormones on platelet aggregation.

    PubMed

    Farré, Antonio López; Modrego, Javier; Zamorano-León, José J

    2014-04-01

    Platelets and their activation/inhibition mechanisms play a central role in haemostasis. It is well known agonists and antagonists of platelet activation; however, during the last years novel evidences of hormone effects on platelet activation have been reported. Platelet functionality may be modulated by the interaction between different hormones and their platelet receptors, contributing to sex differences in platelet function and even in platelet-mediated vascular damage. It has suggested aspects that apparently are well established should be reviewed. Hormones effects on platelet activity are included among them. This article tries to review knowledge about the involvement of hormones in platelet biology and activity.

  14. Current concepts in platelet transfusion

    PubMed Central

    Mohanty, Dipika

    2009-01-01

    This is the era of component therapy. Therefore there is a need for rational use of platelet concentrate. Lot of knowledge has been added recently in the field of platelet specially about the platelet rich plasma and its application in clinical practice. The current review focuses on improvement in preparation of platelet rich plasma, the procedure to make the same more safe and its rational use. Furthermore newer aspects of platelet concentrate use in surgical practice and for regenerative medicine has also been discussed. It also covers some progress and hurdles in preparation of platelet substitutes. PMID:20041092

  15. Arachidonic acid depletion extends survival of cold-stored platelets by interfering with the [glycoprotein Ibα – 14-3-3ζ] association

    PubMed Central

    van der Wal, Dianne E.; Gitz, Eelo; Du, Vivian X.; Lo, Kimberly S.L.; Koekman, Cornelis A.; Versteeg, Sabine; Akkerman, Jan Willem N.

    2012-01-01

    Background Cold storage of platelets reduces bacterial growth and preserves their hemostatic properties better than current procedures do. However, storage at 0°C induces [14-3-3ζ-glycoprotein Ibα] association, 14-3-3ζ release from phospho-Bad, Bad activation and apoptosis. Design and Methods We investigated whether arachidonic acid, which also binds 14-3-3ζ, contributes to coldinduced apoptosis. Results Cold storage activated P38-mitogen-activated protein kinase and released arachidonic acid, which accumulated due to cold inactivation of cyclooxygenase-1/thromboxane synthase. Accumulated arachidonic acid released 14-3-3ζ from phospho-Bad and decreased the mitochondrial membrane potential, which are steps in the induction of apoptosis. Addition of arachidonic acid did the same and its depletion made platelets resistant to cold-induced apoptosis. Incubation with biotin-arachidonic acid revealed formation of an [arachidonic acid-14-3-3ζ-glycoprotein Ibα] complex. Indomethacin promoted complex formation by accumulating arachidonic acid and released 14-3-3ζ from cyclo-oxygenase-1. Arachidonic acid depletion prevented the cold-induced reduction of platelet survival in mice. Conclusions We conclude that cold storage induced apoptosis through an [arachidonic acid-14-3-3ζ-glycoprotein Ibα] complex, which released 14-3-3ζ from Bad in an arachidonic acid-dependent manner. Although arachidonic acid depletion reduced agonist-induced thromboxane A2 formation and aggregation, arachidonic acid repletion restored these functions, opening ways to reduce apoptosis during storage without compromising hemostatic functions post-transfusion. PMID:22371179

  16. Point of care platelet activity measurement in primary PCI [PINPOINT-PPCI]: a protocol paper

    PubMed Central

    2014-01-01

    Background Optimal treatment of acute ST-elevation myocardial infarction (STEMI) involves rapid diagnosis, and transfer to a cardiac centre capable of percutaneous coronary intervention (PCI) for immediate mechanical revascularisation. Successful treatment requires rapid return of perfusion to the myocardium achieved by thromboaspiration, passivation of the culprit lesion with stent scaffolding and systemic inhibition of thrombosis and platelet activation. A delicate balance exists between thrombosis and bleeding and consequently anti-thrombotic and antiplatelet treatment regimens continue to evolve. The desire to achieve reperfusion as soon as possible, in the setting of high platelet reactivity, requires potent and fast-acting anti-thrombotic/anti-platelet therapies. The associated bleeding risk may be minimised by use of short-acting anti-thrombotic intravenous agents. However, effective oral platelet inhibition is required to prevent recurrent thrombosis. The interaction between baseline platelet reactivity, timing of revascularisation and effective inhibition of thrombosis is yet to be formally investigated. Methods/Design We present a protocol for a prospective observational study in patients presenting with acute STEMI treated with primary PCI (PPCI) and receiving bolus/infusion bivalirudin and prasugrel therapy. The objective of this study is to describe variation in platelet reactivity, as measured by the multiplate platelet function analyser, at presentation, the end of the PPCI procedure and 1, 2, & 24 hours post-procedure. We intend to assess the prevalence of high residual platelet reactivity within 24 hours of PPCI in acute STEMI patients receiving prasugrel and bivalirudin. Additionally, we will investigate the association between high platelet reactivity before and after PPCI and the door-to-procedure completion time. This is a single centre study with a target sample size of 108 participants. Discussion The baseline platelet reactivity on

  17. Point of care platelet activity measurement in primary PCI [PINPOINT-PPCI]: a protocol paper.

    PubMed

    Johnson, Thomas W; Marsden, Debbie; Mumford, Andrew; Pike, Katie; Mundell, Stuart; Butler, Mark; Strange, Julian W; Bowles, Ruth; Rogers, Chris; Baumbach, Andreas; Reeves, Barnaby C

    2014-04-04

    Optimal treatment of acute ST-elevation myocardial infarction (STEMI) involves rapid diagnosis, and transfer to a cardiac centre capable of percutaneous coronary intervention (PCI) for immediate mechanical revascularisation. Successful treatment requires rapid return of perfusion to the myocardium achieved by thromboaspiration, passivation of the culprit lesion with stent scaffolding and systemic inhibition of thrombosis and platelet activation. A delicate balance exists between thrombosis and bleeding and consequently anti-thrombotic and antiplatelet treatment regimens continue to evolve. The desire to achieve reperfusion as soon as possible, in the setting of high platelet reactivity, requires potent and fast-acting anti-thrombotic/anti-platelet therapies. The associated bleeding risk may be minimised by use of short-acting anti-thrombotic intravenous agents. However, effective oral platelet inhibition is required to prevent recurrent thrombosis. The interaction between baseline platelet reactivity, timing of revascularisation and effective inhibition of thrombosis is yet to be formally investigated. We present a protocol for a prospective observational study in patients presenting with acute STEMI treated with primary PCI (PPCI) and receiving bolus/infusion bivalirudin and prasugrel therapy. The objective of this study is to describe variation in platelet reactivity, as measured by the multiplate platelet function analyser, at presentation, the end of the PPCI procedure and 1, 2, & 24 hours post-procedure. We intend to assess the prevalence of high residual platelet reactivity within 24 hours of PPCI in acute STEMI patients receiving prasugrel and bivalirudin. Additionally, we will investigate the association between high platelet reactivity before and after PPCI and the door-to-procedure completion time.This is a single centre study with a target sample size of 108 participants. The baseline platelet reactivity on presentation with a STEMI may impact on the

  18. Comparative analysis of human ex vivo–generated platelets vs megakaryocyte-generated platelets in mice: a cautionary tale

    PubMed Central

    Wang, Yuhuan; Hayes, Vincent; Jarocha, Danuta; Sim, Xiuli; Harper, Dawn C.; Fuentes, Rudy; Sullivan, Spencer K.; Gadue, Paul; Chou, Stella T.; Torok-Storb, Beverly J.; Marks, Michael S.; French, Deborah L.

    2015-01-01

    Thrombopoiesis is the process by which megakaryocytes release platelets that circulate as uniform small, disc-shaped anucleate cytoplasmic fragments with critical roles in hemostasis and related biology. The exact mechanism of thrombopoiesis and the maturation pathways of platelets released into the circulation remain incompletely understood. We showed that ex vivo–generated murine megakaryocytes infused into mice release platelets within the pulmonary vasculature. Here we now show that infused human megakaryocytes also release platelets within the lungs of recipient mice. In addition, we observed a population of platelet-like particles (PLPs) in the infusate, which include platelets released during ex vivo growth conditions. By comparing these 2 platelet populations to human donor platelets, we found marked differences: platelets derived from infused megakaryocytes closely resembled infused donor platelets in morphology, size, and function. On the other hand, the PLP was a mixture of nonplatelet cellular fragments and nonuniform-sized, preactivated platelets mostly lacking surface CD42b that were rapidly cleared by macrophages. These data raise a cautionary note for the clinical use of human platelets released under standard ex vivo conditions. In contrast, human platelets released by intrapulmonary-entrapped megakaryocytes appear more physiologic in nature and nearly comparable to donor platelets for clinical application. PMID:25852052

  19. In vitro effect of sodium nitrite on platelet aggregation in human platelet rich plasma--preliminary report.

    PubMed

    Kadan, M; Doğanci, S; Yildirim, V; Özgür, G; Erol, G; Karabacak, K; Avcu, F

    2015-10-01

    The role of nitrates and nitric oxide on platelet functions has obtained an increasing attention with respect to their potential effects on cardiovascular disorders. In this study we aimed to analyze the effect of sodium nitrite on platelet functions in human platelets. This in vitro study was designed to show the effect of sodium nitrite on platelet functions in seven healthy volunteers. Blood samples were centrifuged to prepare platelet rich plasma and platelet poor plasma. Platelet rich plasma was diluted with the platelet poor plasma to have a final count of 300,000 ± 25,000 platelets. Platelet rich plasma was incubated with six different increasing doses (from 10 μM to 5 mM) of sodium nitrite for 1 hour at 37°C. Then stimulating agents including collagen (3 μg ml-1), adenosine diphosphate (10 μM), and epinephrine (10 μM) were added to the cuvette. Changes in light transmission were observed for 10 minutes. In addition spontaneous aggregation were performed in control group with all aggregating agents separately. Effect of sodium nitrite on agonist-induced platelet aggregation depends on the concentration of sodium nitrite. Compared with control group, agonist-induced platelet aggregations were significantly suppressed by sodium nitrite at the concentration of 5, 1.0 and 0.5 mM. Our results suggested that sodium nitrite has inhibitory effects in vitro on platelet aggregation in a dose-dependent manner.

  20. Increasing platelet concentrations in leukocyte-reduced platelet-rich plasma decrease collagen gene synthesis in tendons.

    PubMed

    Boswell, Stacie G; Schnabel, Lauren V; Mohammed, Hussni O; Sundman, Emily A; Minas, Tom; Fortier, Lisa A

    2014-01-01

    Platelet-rich plasma (PRP) is used for the treatment of tendinopathy. There are numerous PRP preparations, and the optimal combination of platelets and leukocytes is not known. Within leukocyte-reduced PRP (lrPRP), there is a plateau effect of platelet concentration, with increasing platelet concentrations being detrimental to extracellular matrix synthesis. Controlled laboratory study. Different formulations of lrPRP with respect to the platelet:leukocyte ratio were generated from venous blood of 8 horses. Explants of the superficial digital flexor tendon were cultured in lrPRP products for 96 hours. Platelet-derived growth factor-BB (PDGF-BB), tumor necrosis factor-α (TNF-α), transforming growth factor-β1 (TGF-β1), and interleukin-1β (IL-1β) concentrations were determined in the media by enzyme-linked immunosorbent assay. Gene expression in tendon tissue for collagen type I and III (COL1A1 and COL3A1, respectively), matrix metalloproteinase-3 and -13 (MMP-3 and MMP-13, respectively), cartilage oligomeric matrix protein (COMP), and IL-1β was determined. Data were divided into 3 groups of lrPRP based on the ratio of platelets:leukocytes and evaluated to determine the effect of platelet concentration. Complete blood counts verified leukocyte reduction and platelet enrichment in all PRP preparations. In the lrPRP preparation, the anabolic growth factors PDGF-BB and TGF-β1 were increased with increasing platelet concentrations, and the catabolic cytokine IL-1β was decreased with increasing platelet concentrations. Increasing the platelet concentration resulted in a significant reduction in COL1A1 and COL3A1 synthesis in tendons. Increasing the platelet concentration within lrPRP preparations results in the delivery of more anabolic growth factors and less proinflammatory cytokines, but the biological effect on tendons is diminished metabolism as indicated by a decrease in the synthesis of both COL1A1 and COL3A1. Together, this information suggests that

  1. Prophylactic platelet transfusions prior to surgery for people with a low platelet count

    PubMed Central

    Estcourt, Lise J; Malouf, Reem; Doree, Carolyn; Trivella, Marialena; Hopewell, Sally; Birchall, Janet

    2017-01-01

    This is a protocol for a Cochrane Review (Intervention). The objectives are as follows: To determine the clinical effectiveness and safety of prophylactic platelet transfusions prior to surgery for people with a low platelet count or platelet dysfunction (inherited or acquired). PMID:29151812

  2. Comparison of Immature Platelet Count to Established Predictors of Platelet Reactivity During Thienopyridine Therapy.

    PubMed

    Stratz, Christian; Bömicke, Timo; Younas, Iris; Kittel, Anja; Amann, Michael; Valina, Christian M; Nührenberg, Thomas; Trenk, Dietmar; Neumann, Franz-Josef; Hochholzer, Willibald

    2016-07-19

    Previous data suggest that reticulated platelets significantly affect antiplatelet response to thienopyridines. It is unknown whether parameters describing reticulated platelets can predict antiplatelet response to thienopyridines. The authors sought to determine the extent to which parameters describing reticulated platelets can predict antiplatelet response to thienopyridine loading compared with established predictors. This study randomized 300 patients undergoing elective coronary stenting to loading with clopidogrel 600 mg, prasugrel 30 mg, or prasugrel 60 mg. Adenosine diphosphate (ADP)-induced platelet reactivity was assessed by impedance aggregometry before loading (intrinsic platelet reactivity) and again on day 1 after loading. Multiple parameters of reticulated platelets were assessed by automated whole blood flow cytometry: absolute immature platelet count (IPC), immature platelet fraction, and highly fluorescent immature platelet fraction. Each parameter of reticulated platelets correlated significantly with ADP-induced platelet reactivity (p < 0.01 for all 3 parameters). In a multivariable model including all 3 parameters, only IPC remained a significant predictor of platelet reactivity (p < 0.001). In models adjusting each of the 3 parameters for known predictors of on-treatment platelet reactivity including cytochrome P450 2C19 (CYP2C19) polymorphisms, age, body mass index, diabetes, and intrinsic platelet reactivity, only IPC prevailed as an independent predictor (p = 0.001). In this model, IPC was the strongest predictor of on-treatment platelet reactivity followed by intrinsic platelet reactivity. IPC is the strongest independent platelet count-derived predictor of antiplatelet response to thienopyridine treatment. Given its easy availability, together with its even stronger association with on-treatment platelet reactivity compared with known predictors, including the CYP2C19*2 polymorphism, IPC may become the preferred predictor of

  3. Platelets promote osteosarcoma cell growth through activation of the platelet-derived growth factor receptor-Akt signaling axis.

    PubMed

    Takagi, Satoshi; Takemoto, Ai; Takami, Miho; Oh-Hara, Tomoko; Fujita, Naoya

    2014-08-01

    The interactions of tumor cells with platelets contribute to the progression of tumor malignancy, and the expression levels of platelet aggregation-inducing factors positively correlate with the metastatic potential of osteosarcoma cells. However, it is unclear how tumor-platelet interaction contributes to the proliferation of osteosarcomas. We report here that osteosarcoma-platelet interactions induce the release of platelet-derived growth factor (PDGF) from platelets, which promotes the proliferation of osteosarcomas. Co-culture of platelets with MG63 or HOS osteosarcoma cells, which could induce platelet aggregation, enhanced the proliferation of each cell line in vitro. Analysis of phospho-antibody arrays revealed that co-culture of MG63 cells with platelets induced the phosphorylation of platelet derived growth factor receptor (PDGFR) and Akt. The addition of supernatants of osteosarcoma-platelet reactants also increased the growth of MG63 and HOS cells as well as the level of phosphorylated-PDGFR and -Akt. Sunitinib or LY294002, but not erlotinib, significantly inhibited the platelet-induced proliferation of osteosarcoma cells, indicating that PDGF released from platelets plays an important role in the proliferation of osteosarcomas by activating the PDGFR and then Akt. Our results suggest that inhibitors that specifically target osteosarcoma-platelet interactions may eradicate osteosarcomas. © 2014 The Authors. Cancer Science published by Wiley Publishing Asia Pty Ltd on behalf of Japanese Cancer Association.

  4. Aspirin inhibition of platelet deposition at angioplasty sites: demonstration by platelet scintigraphy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cuningham, D.A.; Kumar, B.; Siegel, B.A.

    In-111 platelet scintigraphy was used to evaluate the effects of prior aspirin administration on the accumulation of In-111-labeled autologous platelets at sites of arterial injury resulting from iliac, femoral, or popliteal transluminal angioplasty in a nonrandomized study of 17 men. The degree of platelet localization at angioplasty sites was significantly less in nine men who had received aspirin in varying doses within the 4 days before angioplasty than in eight men who had not received aspirin for at least two weeks. The results suggest that aspirin treatment before angioplasty limits the early platelet deposition at the angioplasty site in men.

  5. A novel platelet concentrate: titanium-prepared platelet-rich fibrin.

    PubMed

    Tunalı, Mustafa; Özdemir, Hakan; Küçükodacı, Zafer; Akman, Serhan; Yaprak, Emre; Toker, Hülya; Fıratlı, Erhan

    2014-01-01

    We developed a new product called titanium-prepared platelet-rich fibrin (T-PRF). The T-PRF method is based on the hypothesis that titanium may be more effective in activating platelets than the silica activators used with glass tubes in Chouckroun's leukocyte- and platelet-rich fibrin (L-PRF) method. In this study, we aimed to define the structural characteristics of T-PRF and compare it with L-PRF. Blood samples were collected from 10 healthy male volunteers. The blood samples were drawn using a syringe. Nine milliliters was transferred to a dry glass tube, and 9 mL was transferred to a titanium tube. Half of each clot (i.e., the blood that was clotted using T-PRF or L-PRF) was processed with a scanning electron microscope (SEM). The other half of each clot was processed for fluorescence microscopy analysis and light microscopy analysis. The T-PRF samples seemed to have a highly organized network with continuous integrity compared to the other L-PRF samples. Histomorphometric analysis showed that T-PRF fibrin network covers larger area than L-PRF fibrin network; also fibrin seemed thicker in the T-PRF samples. This is the first human study to define T-PRF as an autogenous leukocyte- and platelet-rich fibrin product. The platelet activation by titanium seems to offer some high characteristics to T-PRF.

  6. Negative feedback regulation of human platelets via autocrine activation of the platelet-derived growth factor alpha-receptor.

    PubMed

    Vassbotn, F S; Havnen, O K; Heldin, C H; Holmsen, H

    1994-05-13

    Human platelets contain platelet-derived growth factor (PDGF) in their alpha-granules which is released during platelet exocytosis. We show by immunoprecipitation and 125I-PDGF binding experiments that human platelets have functionally active PDGF alpha-receptors, but not beta-receptors. The PDGF alpha-receptor (PDGFR-alpha) was identified as a 170-kDa glycosylated protein-tyrosine kinase as found in other cell types. Stimulation of platelets with 0.1 unit/ml thrombin resulted in a significant increase (2-5-fold) of the tyrosine phosphorylation of the PDGFR-alpha, as determined by immunoprecipitation with phosphotyrosine antiserum as well as with PDGFR-alpha antiserum. The observed thrombin-induced autophosphorylation of the PDGFR-alpha was inhibited by the addition of a neutralizing monoclonal PDGF antibody. Thus, our results suggest that the platelet PDGFR-alpha is stimulated in an autocrine manner by PDGF secreted during platelet activation. Preincubation of platelets with PDGF inhibited thrombin-induced platelet aggregation and secretion of ATP + ADP and beta-hexosaminidase. Thrombin-induced platelet aggregation was also reversed when PDGF was added 30 s after thrombin stimulation. Inhibition of the autocrine PDGF pathway during platelet activation by the PDGF antibody led to a potentiation of thrombin-induced beta-hexosaminidase secretion. Thus, the PDGFR-alpha takes part in a negative feedback regulation during platelet activation. Our demonstration of PDGF alpha-receptors on human platelets and its inhibitory function during platelet activation identifies a new possible role of PDGF in the regulation of thrombosis.

  7. Flow cytometric assessment of activation of peripheral blood platelets in dogs with normal platelet count and asymptomatic thrombocytopenia.

    PubMed

    Żmigrodzka, M; Guzera, M; Winnicka, A

    2016-01-01

    Platelets play a crucial role in hemostasis. Their activation has not yet been evaluated in healthy dogs with a normal and low platelet count. The aim of this study was to determine the influence of activators on platelet activation in dogs with a normal platelet count and asymptomatic thrombocytopenia. 72 clinically healthy dogs were enrolled. Patients were allocated into three groups. Group 1 consisted of 30 dogs with a normal platelet count, group 2 included 22 dogs with a platelet count between 100 and 200×109/l and group 3 consisted of 20 dogs with a platelet count lower than 100×109/l. Platelet rich-plasma (PRP) was obtained from peripheral blood samples using tripotassium ethylenediaminetetraacetic acid (K3-EDTA) as anticoagulant. Next, platelets were stimulated using phorbol-12-myristate-13-acetate or thrombin, stabilized using procaine or left unstimulated. The expression of CD51 and CD41/CD61 was evaluated. Co-expression of CD41/CD61 and Annexin V served as a marker of platelet activation. The expression of CD41/CD61 and CD51 did not differ between the 3 groups. Thrombin-stimulated platelets had a significantly higher activity in dogs with a normal platelet count than in dogs with asymptomatic thrombocytopenia. Procaine inhibited platelet activity in all groups. In conclusion, activation of platelets of healthy dogs in vitro varied depending on the platelet count and platelet activator.

  8. Treatment of Knee Osteochondral Lesions Using a Novel Clot of Autologous Plasma Rich in Growth Factors Mixed with Healthy Hyaline Cartilage Chips and Intra-Articular Injection of PRGF

    PubMed Central

    Alentorn-Geli, Eduard; Steinbacher, Gilbert; Álvarez-Díaz, Pedro; Cuscó, Xavier; Seijas, Roberto; Barastegui, David; Navarro, Jordi; Laiz, Patricia; García-Balletbó, Montserrat

    2017-01-01

    Knee cartilage or osteochondral lesions are common and challenging injuries. To date, most symptomatic lesions warrant surgical treatment. We present two cases of patients with knee osteochondral defects treated with a one-step surgical procedure consisting of an autologous-based matrix composed of healthy hyaline cartilage chips, mixed plasma poor-rich in platelets clot, and plasma rich in growth factors (PRGF). Both patients returned to playing soccer at the preinjury activity level and demonstrated excellent defect filling in both magnetic resonance imaging and second-look arthroscopy (in one of them). The use of a clot of autologous plasma poor in platelets with healthy hyaline cartilage chips and intra-articular injection of plasma rich in platelets is an effective, easy, and cheap option to treat knee cartilage injuries in young and athletic patients. PMID:28798878

  9. Treatment of Knee Osteochondral Lesions Using a Novel Clot of Autologous Plasma Rich in Growth Factors Mixed with Healthy Hyaline Cartilage Chips and Intra-Articular Injection of PRGF.

    PubMed

    Cugat, Ramón; Alentorn-Geli, Eduard; Steinbacher, Gilbert; Álvarez-Díaz, Pedro; Cuscó, Xavier; Seijas, Roberto; Barastegui, David; Navarro, Jordi; Laiz, Patricia; García-Balletbó, Montserrat

    2017-01-01

    Knee cartilage or osteochondral lesions are common and challenging injuries. To date, most symptomatic lesions warrant surgical treatment. We present two cases of patients with knee osteochondral defects treated with a one-step surgical procedure consisting of an autologous-based matrix composed of healthy hyaline cartilage chips, mixed plasma poor-rich in platelets clot, and plasma rich in growth factors (PRGF). Both patients returned to playing soccer at the preinjury activity level and demonstrated excellent defect filling in both magnetic resonance imaging and second-look arthroscopy (in one of them). The use of a clot of autologous plasma poor in platelets with healthy hyaline cartilage chips and intra-articular injection of plasma rich in platelets is an effective, easy, and cheap option to treat knee cartilage injuries in young and athletic patients.

  10. Platelets and atherogenesis: Platelet anti-aggregation activity and endothelial protection from tomatoes (Solanum lycopersicum L.)

    PubMed Central

    PALOMO, IVÁN; FUENTES, EDUARDO; PADRÓ, TERESA; BADIMON, LINA

    2012-01-01

    In recent years, it has been shown that platelets are not only involved in the arterial thrombotic process, but also that they play an active role in the inflammatory process of atherogenesis from the beginning. The interaction between platelets and endothelial cells occurs in two manners: activated platelets unite with intact endothelial cells, or platelets in resting adhere to activated endothelium. In this context, inhibition of the platelet function (adhesion/aggregation) could contribute to the prevention of atherothrombosis, the leading cause of cardiovascular morbidity. This can be achieved with antiplatelet agents. However, at the public health level, the level of primary prevention, a healthy diet has also been shown to exert beneficial effects. Among those elements of a healthy diet, the consumption of tomatoes (Solanum lycopersicum L.) stands out for its effect on platelet anti-aggregation activity and endothelial protection, which may be beneficial for cardiovascular health. This article briefly discusses the involvement of platelets in atherogenesis and the possible mechanisms of action provided by tomatoes for platelet anti-aggregation activity and endothelial protection. PMID:22969932

  11. The role of platelets during reproduction.

    PubMed

    Isermann, Berend; Nawroth, Peter P

    2006-01-01

    The availability of mice with defined defects within the hemostatic system enabled researchers to identify a role the coagulation system for embryonic and placental development. However, the role of platelets during development has only recently been experimentally addressed, giving some insight into potential functions of platelets during development. Thus, a quantitative embryonic platelet defect (severe thrombopenia secondary to NF-E2 deficiency) is associated with an embryonic growth retardation and reduced vascularisation of the placenta. Maternal platelet deficiency is associated with placental hemorrhage, which, however, does not impair embryonic or maternal survival. In vitro studies established that platelets or platelet conditioned medium regulate the invasive properties of human extravillous trophoblast cells and induce a phenotypical switch of trophoblast cells. These data imply that platelets are of relevance during placentation. Conversely, platelets and the formation of platelet-fibrin aggregates are dispensable for the development of the embryo proper, establishing that the lethal phenotypes observed in some embryo slacking coagulation regulators does not result from an inability to form platelet-fibrin aggregates, but likely reflects altered protease dependent signaling during vascular development.

  12. Platelet-derived growth factor-BB has neurorestorative effects and modulates the pericyte response in a partial 6-hydroxydopamine lesion mouse model of Parkinson's disease.

    PubMed

    Padel, Thomas; Özen, Ilknur; Boix, Jordi; Barbariga, Marco; Gaceb, Abderahim; Roth, Michaela; Paul, Gesine

    2016-10-01

    Parkinson's disease (PD) is a neurodegenerative disease where the degeneration of the nigrostriatal pathway leads to specific motor deficits. There is an unmet medical need for regenerative treatments that stop or reverse disease progression. Several growth factors have been investigated in clinical trials to restore the dopaminergic nigrostriatal pathway damaged in PD. Platelet-derived growth factor-BB (PDGF-BB), a molecule that recruits pericytes to stabilize microvessels, was recently investigated in a phase-1 clinical trial, showing a dose-dependent increase in dopamine transporter binding in the putamen of PD patients. Interestingly, evidence is accumulating that PD is paralleled by microvascular changes, however, whether PDGF-BB modifies pericytes in PD is not known. Using a pericyte reporter mouse strain, we investigate the functional and restorative effect of PDGF-BB in a partial 6-hydroxydopamine medial forebrain bundle lesion mouse model of PD, and whether this restorative effect is accompanied by changes in pericyte features. We demonstrate that a 2-week treatment with PDGF-BB leads to behavioural recovery using several behavioural tests, and partially restores the nigrostriatal pathway. Interestingly, we find that pericytes are activated in the striatum of PD lesioned mice and that these changes are reversed by PDGF-BB treatment. The modulation of brain pericytes may contribute to the PDGF-BB-induced neurorestorative effects, PDGF-BB allowing for vascular stabilization in PD. Pericytes might be a new cell target of interest for future regenerative therapies. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  13. Platelet-activated clotting time does not measure platelet reactivity during cardiac surgery.

    PubMed

    Shore-Lesserson, L; Ammar, T; DePerio, M; Vela-Cantos, F; Fisher, C; Sarier, K

    1999-08-01

    Platelet dysfunction is a major contributor to bleeding after cardiopulmonary bypass (CPB), yet it remains difficult to diagnose. A point-of-care monitor, the platelet-activated clotting time (PACT), measures accelerated shortening of the kaolin-activated clotting time by addition of platelet activating factor. The authors sought to evaluate the clinical utility of the PACT by conducting serial measurements of PACT during cardiac surgery and correlating postoperative measurements with blood loss. In 50 cardiac surgical patients, blood was sampled at 10 time points to measure PACT. Simultaneously, platelet reactivity was measured by the thrombin receptor agonist peptide-induced expression of P-selectin, using flow cytometry. These tests were temporally analyzed. PACT values, P-selectin expression, and other coagulation tests were analyzed for correlation with postoperative chest tube drainage. PACT and P-selectin expression were maximally reduced after protamine administration. Changes in PACT did not correlate with changes in P-selectin expression at any time interval. Total 8-h chest tube drainage did not correlate with any coagulation test at any time point except with P-selectin expression after protamine administration (r = -0.4; P = 0.03). The platelet dysfunction associated with CPB may be a result of depressed platelet reactivity, as shown by thrombin receptor activating peptide-induced P-selectin expression. Changes in PACT did not correlate with blood loss or with changes in P-selectin expression suggesting that PACT is not a specific measure of platelet reactivity.

  14. Effects of isotretinoin on the platelet counts and the mean platelet volume in patients with acne vulgaris.

    PubMed

    Ataseven, Arzu; Ugur Bilgin, Aynur

    2014-01-01

    Aim. The aim of this study was to evaluate the platelet counts and the mean platelet volume in patients who received isotretinoin for the treatment of acne vulgaris. Method. A total of 110 patients were included in this retrospective study. Complete blood count parameters were recorded prior to and three-months following the treatment. Results. Both platelet counts and the mean platelet volume were significantly decreased following the treatment. No significant differences were noted on the levels of hemoglobin, hematocrit, and white blood cell count. Conclusion. Platelet counts and mean platelet volume significantly decreased following isotretinoin treatment. Since the decrease of platelet counts and the mean platelet volume was seen concomitantly, it is concluded that the effect of isotretinoin was through the suppression of bone marrow.

  15. Platelet response heterogeneity in thrombus formation.

    PubMed

    Munnix, Imke C A; Cosemans, Judith M E M; Auger, Jocelyn M; Heemskerk, Johan W M

    2009-12-01

    Vascular injury leads to formation of a structured thrombus as a consequence of platelet activation and aggregation, thrombin and fibrin formation, and trapping of leukocytes and red cells. This review summarises current evidence for heterogeneity of platelet responses and functions in the thrombus-forming process. Environmental factors contribute to response heterogeneity, as the platelets in a thrombus adhere to different substrates, and sense specific (ant)agonists and rheological conditions. Contraction of platelets and interaction with fibrin and other blood cells cause further response variation. On the other hand, response heterogeneity can also be due to intrinsic differences between platelets in age and in receptor and signalling proteins. As a result, at least three subpopulations of platelets are formed in a thrombus: aggregating platelets with (reversible) integrin activation, procoagulant (coated) platelets exposing phosphatidylserine and binding coagulation factors, and contracting platelets with cell-cell contacts. This recognition of thrombus heterogeneity has implications for the use and development of antiplatelet medication.

  16. Blocking of platelets or intrinsic coagulation pathway-driven thrombosis does not prevent cerebral infarctions induced by photothrombosis.

    PubMed

    Kleinschnitz, Christoph; Braeuninger, Stefan; Pham, Mirko; Austinat, Madeleine; Nölte, Ingo; Renné, Thomas; Nieswandt, Bernhard; Bendszus, Martin; Stoll, Guido

    2008-04-01

    Models of photochemically-induced thrombosis are widely used in cerebrovascular research. Photothrombotic brain infarctions can be induced by systemic application of photosensitizing dyes followed by focal illumination of the cerebral cortex. Although the ensuing activation of platelets is well established, their contribution for thrombosis and tissue damage has not formally been proved. Infarction to the cerebral cortex was induced in mice by Rose Bengal and a cold light source. To assess the functional role of platelets, animals were platelet-depleted by anti-GPIbalpha antibodies or treated with GPIIb/IIIa-blocking F(ab)(2) fragments. The significance of the plasmatic coagulation cascade was determined by using blood coagulation factor XII (FXII)-deficient mice or heparin. Infarct development and infarct volumes were determined by serial MRI and conventional and electron microscopy. There was no difference in development and final size of photothrombotic infarctions in mice with impaired platelet function. Moreover, deficiency of FXII, which initiates the intrinsic pathway of coagulation and is essential for thrombus formation, or blockade of FXa, the key protease during the waterfall cascade of plasmatic coagulation, by heparin likewise did not affect lesion development. Our data demonstrate that platelet activation, factor XII-driven thrombus formation, and plasmatic coagulation pathways downstream of FX are not a prerequisite for ensuing tissue damage in models of photothrombotic vessel injury indicating that other pathomechanisms are involved. We suggest that this widely used model does not depend on platelet- or plasmatic coagulation-derived thrombosis.

  17. Engineering Factor Xa Inhibitor with Multiple Platelet-Binding Sites Facilitates its Platelet Targeting

    NASA Astrophysics Data System (ADS)

    Zhu, Yuanjun; Li, Ruyi; Lin, Yuan; Shui, Mengyang; Liu, Xiaoyan; Chen, Huan; Wang, Yinye

    2016-07-01

    Targeted delivery of antithrombotic drugs centralizes the effects in the thrombosis site and reduces the hemorrhage side effects in uninjured vessels. We have recently reported that the platelet-targeting factor Xa (FXa) inhibitors, constructed by engineering one Arg-Gly-Asp (RGD) motif into Ancylostoma caninum anticoagulant peptide 5 (AcAP5), can reduce the risk of systemic bleeding than non-targeted AcAP5 in mouse arterial injury model. Increasing the number of platelet-binding sites of FXa inhibitors may facilitate their adhesion to activated platelets, and further lower the bleeding risks. For this purpose, we introduced three RGD motifs into AcAP5 to generate a variant NR4 containing three platelet-binding sites. NR4 reserved its inherent anti-FXa activity. Protein-protein docking showed that all three RGD motifs were capable of binding to platelet receptor αIIbβ3. Molecular dynamics simulation demonstrated that NR4 has more opportunities to interact with αIIbβ3 than single-RGD-containing NR3. Flow cytometry analysis and rat arterial thrombosis model further confirmed that NR4 possesses enhanced platelet targeting activity. Moreover, NR4-treated mice showed a trend toward less tail bleeding time than NR3-treated mice in carotid artery endothelium injury model. Therefore, our data suggest that engineering multiple binding sites in one recombinant protein is a useful tool to improve its platelet-targeting efficiency.

  18. Platelets Inhibit Migration of Canine Osteosarcoma Cells.

    PubMed

    Bulla, S C; Badial, P R; Silva, R C; Lunsford, K; Bulla, C

    2017-01-01

    The interaction between platelets and tumour cells is important for tumour growth and metastasis. Thrombocytopenia or antiplatelet treatment negatively impact on cancer metastasis, demonstrating potentially important roles for platelets in tumour progression. To our knowledge, there is no information regarding the role of platelets in cancer progression in dogs. This study was designed to test whether canine platelets affected the migratory behaviour of three canine osteosarcoma cell lines and to give insights of molecular mechanisms. Intact platelets, platelet lysate and platelet releasate inhibited the migration of canine osteosarcoma cell lines. Addition of blood leucocytes to the platelet samples did not alter the inhibitory effect on migration. Platelet treatment also significantly downregulated the transcriptional levels of SNAI2 and TWIST1 genes. The interaction between canine platelets or molecules released during platelet activation and these tumour cell lines inhibits their migration, which suggests that canine platelets might antagonize metastasis of canine osteosarcoma. This effect is probably due to, at least in part, downregulation of genes related to epithelial-mesenchymal transition. Copyright © 2016. Published by Elsevier Ltd.

  19. Reference Range of Platelet Delta Granules in the Pediatric Age Group: An Ultrastructural Study of Platelet Whole Mount Preparations from Healthy Volunteers.

    PubMed

    Sorokin, Victoria; Alkhoury, Razan; Al-Rawabdeh, Sura; Houston, Ronald H; Thornton, David; Kerlin, Bryce; O'Brien, Sarah; Baker, Peter; Boesel, Carl; Uddin, Minhaj; Yin, Han; Kahwash, Samir

    This study sought to determine delta granule normal ranges for children and to validate methodology for the appropriate diagnosis of delta granule deficiency (storage pool disease) by using the whole-mount technique in electron microscopy. Specimens obtained from 40 healthy volunteers (2 months of age through 21 years old, 21 females and 19 males) were tested. Results showed dense granules/platelet (DG/Plt) ranged from 1.78 to 5.25. The 5th percentile was 1.96 DG/Plt with an overall mean ± SEM 3.07 ± 0.12 DG/Plt. In comparison, a previously published lower cutoff value, 3.68 DG/Plt, was significantly higher than the mean from our volunteers (P < 0.0001). We found no variability in dense granules/platelet based on race or sex and no significant variation by age subgroup. Pending wider studies, the value of 2 DG/Plt is a more appropriate lower limit of normal. In the absence of wider studies (in healthy volunteers and patients), laboratories should consider establishing their own reference ranges.

  20. Clot lysis time in platelet-rich plasma: method assessment, comparison with assays in platelet-free and platelet-poor plasmas, and response to tranexamic acid.

    PubMed

    Panes, Olga; Padilla, Oslando; Matus, Valeria; Sáez, Claudia G; Berkovits, Alejandro; Pereira, Jaime; Mezzano, Diego

    2012-01-01

    Fibrinolysis dysfunctions cause bleeding or predisposition to thrombosis. Platelets contain several factors of the fibrinolytic system, which could up or down regulate this process. However, the temporal relationship and relative contributions of plasma and platelet components in clot lysis are mostly unknown. We developed a clot lysis time (CLT) assay in platelet-rich plasma (PRP-CLT, with and without stimulation) and compared it to a similar one in platelet-free plasma (PFP) and to another previously reported test in platelet-poor plasma (PPP). We also studied the differential effects of a single dose of tranexamic acid (TXA) on these tests in healthy subjects. PFP- and PPP-CLT were significantly shorter than PRP-CLT, and the three assays were highly correlated (p < 0.0001). PFP- and PPP-, but more significantly PRP-CLT, were positively correlated with age and plasma PAI-1, von Willebrand factor, fibrinogen, LDL-cholesterol, and triglycerides (p < 0.001). All these CLT assays had no significant correlations with platelet aggregation/secretion, platelet counts, and pro-coagulant tests to explore factor X activation by platelets, PRP clotting time, and thrombin generation in PRP. Among all the studied variables, PFP-CLT was independently associated with plasma PAI-1, LDL-cholesterol, and triglycerides and, additionally, stimulated PRP-CLT was also independently associated with plasma fibrinogen. A single 1 g dose of TXA strikingly prolonged all three CLTs, but in contrast to the results without the drug, the lysis times were substantially shorter in non-stimulated or stimulated PRP than in PFP and PPP. This standardized PRP-CLT may become a useful tool to study the role of platelets in clot resistance and lysis. Our results suggest that initially, the platelets enmeshed in the clot slow down the fibrinolysis process. However, the increased clot resistance to lysis induced by TXA is overcome earlier in platelet-rich clots than in PFP or PPP clots. This is

  1. Platelet compatibility of magnesium alloys.

    PubMed

    Yahata, Chie; Mochizuki, Akira

    2017-09-01

    Lately, Mg alloys have been investigated as a new class of biomaterials owing to their excellent biodegradability and biocompatibility. It has previously been reported that the in vitro compatibility of a Mg alloy containing aluminum and zinc (AZ) alloy with the blood coagulation system is excellent due to Mg 2+ ions eluting from the alloy. In this study, the compatibility of the AZ alloy with platelets was evaluated by scanning electron microscopy (SEM) and flow cytometry. In the flow cytometry analysis, the platelets were stained using PAC-1 and P-selectin antibodies. SEM images and PAC-1 analyses showed no negative effects on the platelets, whereas P-selectin analysis showed marked platelet activation. To understand these contradictory results, the amount of β-thromboglobulin (β-TG) released from the platelets was investigated. From that investigation, it was concluded that platelets are markedly activated by the alloys. In addition to clarifying divergent results depending on the analysis method used, the effects of Mg 2+ ions and pH on platelet activation were studied. These results show that platelet activation is caused by an increase in pH at the alloy surface owing to the erosion of the alloy. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Extension of platelet shelf life from 4 to 5 days by implementation of a new screening strategy in Germany.

    PubMed

    Sireis, W; Rüster, B; Daiss, C; Hourfar, M K; Capalbo, G; Pfeiffer, H-U; Janetzko, K; Goebel, M; Kempf, V A J; Seifried, E; Schmidt, M

    2011-10-01

    The Paul-Ehrlich-Institute analysed all fatalities due to bacterial infections between 1997 and 2007. Thereafter, the platelet shelf life was reduced to a maximum of 4 days after blood donation because the majority of all cases of severe transfusion-transmitted bacterial infections occurred with day 5 platelets. The current study compares the analytical sensitivity and the diagnostic specificity of four rapid bacterial detection procedures. Nine transfusion-relevant bacterial strains were spiked in pooled platelets or apheresis platelets at a low concentration (10 CFU/bag). Samples were collected after day 3, day 4 and day 5 and investigated by four rapid bacterial detection methods (modified BacT/ALERT, Bactiflow, FACS method and 16s DNA PCR methods). Seven out of nine bacterial strains were adequately detected by BacT/ALERT, Bactiflow and PCR in apheresis platelets and pooled platelets after sample collection at day 3, day 4 and day 5. For three bacterial strains, analytical sensitivity was reduced for the FACS method. Two bacterial strains did not grow under the storage conditions in either pooled or apheresis platelets. A late sample collection on day 3, day 4 or day 5 after blood donation in combination with a rapid bacterial detection method offers a new opportunity to improve blood safety and reduce errors due to sampling., BacT/ALERT, Bactiflow or 16s ID-NAT are feasible for late bacterial screening in platelets may provide data which support the extension of platelet shelf life in Germany to 5 days. © 2011 The Author(s). Vox Sanguinis © 2011 International Society of Blood Transfusion.

  3. Unaltered Angiogenesis-Regulating Activities of Platelets in Mild Type 2 Diabetes Mellitus despite a Marked Platelet Hyperreactivity.

    PubMed

    Miao, Xinyan; Zhang, Wei; Huang, Zhangsen; Li, Nailin

    2016-01-01

    Type 2 diabetes mellitus (T2DM) is associated with platelet dysfunction and impaired angiogenesis. Aim of the study is to investigate if platelet dysfunction might hamper platelet angiogenic activities in T2DM patients. Sixteen T2DM patients and gender/age-matched non-diabetic controls were studied. Flow cytometry and endothelial colony forming cell (ECFC) tube formation on matrigel were used to assess platelet reactivity and angiogenic activity, respectively. Thrombin receptor PAR1-activating peptide (PAR1-AP) induced higher platelet P-selectin expression, and evoked more rapid and intense platelet annexin V binding in T2DM patients, seen as a more rapid increase of annexin V+ platelets (24.3±6.4% vs 12.6±3.8% in control at 2 min) and a higher elevation (30.9±5.1% vs 24.3±3.0% at 8 min). However, PAR1-AP and PAR4-AP induced similar releases of angiogenic regulators from platelets, and both stimuli evoked platelet release of platelet angiogenic regulators to similar extents in T2DM and control subjects. Thus, PAR1-stimulated platelet releasate (PAR1-PR) and PAR4-PR similarly enhanced capillary-like network/tube formation of ECFCs, and the enhancements did not differ between T2DM and control subjects. Direct supplementation of platelets to ECFCs at the ratio of 1:200 enhanced ECFC tube formation even more markedly, leading to approximately 100% increases of the total branch points of ECFC tube formation, for which the enhancements were also similar between patients and controls. In conclusion, platelets from T2DM subjects are hyperreactive. Platelet activation induced by high doses of PAR1-AP, however, results in similar releases of angiogenic regulators in mild T2DM and control subjects. Platelets from T2DM and control subjects also demonstrate similar enhancements on ECFC angiogenic activities.

  4. Platelet factor XIII increases the fibrinolytic resistance of platelet-rich clots by accelerating the crosslinking of alpha 2-antiplasmin to fibrin

    NASA Technical Reports Server (NTRS)

    Reed, G. L.; Matsueda, G. R.; Haber, E.

    1992-01-01

    Platelet clots resist fibrinolysis by plasminogen activators. We hypothesized that platelet factor XIII may enhance the fibrinolytic resistance of platelet-rich clots by catalyzing the crosslinking of alpha 2-antiplasmin (alpha 2AP) to fibrin. Analysis of plasma clot structure by polyacrylamide gel electrophoresis and immunoblotting revealed accelerated alpha 2AP-fibrin crosslinking in platelet-rich compared with platelet-depleted plasma clots. A similar study of clots formed with purified fibrinogen (depleted of factor XIII activity), isolated platelets, and specific factor XIII inhibitors indicated that this accelerated crosslinking was due to the catalytic activity of platelet factor XIII. Moreover, when washed platelets were aggregated by thrombin, there was evidence of platelet factor XIII-mediated crosslinking between platelet alpha 2AP and platelet fibrin(ogen). Specific inhibition (by a monoclonal antibody) of the alpha 2AP associated with washed platelet aggregates accelerated the fibrinolysis of the platelet aggregate. Thus in platelet-rich plasma clots, and in thrombin-induced platelet aggregates, platelet factor XIII actively formed alpha 2AP-fibrin crosslinks, which appeared to enhance the resistance of platelet-rich clots to fibrinolysis.

  5. Acidosis downregulates platelet haemostatic functions and promotes neutrophil proinflammatory responses mediated by platelets.

    PubMed

    Etulain, Julia; Negrotto, Soledad; Carestia, Agostina; Pozner, Roberto Gabriel; Romaniuk, María Albertina; D'Atri, Lina Paola; Klement, Giannoula Lakka; Schattner, Mirta

    2012-01-01

    Acidosis is one of the hallmarks of tissue injury such as trauma, infection, inflammation, and tumour growth. Although platelets participate in the pathophysiology of all these processes, the impact of acidosis on platelet biology has not been studied outside of the quality control of laboratory aggregation assays or platelet transfusion optimization. Herein, we evaluate the effect of physiologically relevant changes in extracellular acidosis on the biological function of platelets, placing particular emphasis on haemostatic and secretory functions. Platelet haemostatic responses such as adhesion, spreading, activation of αIIbβ3 integrin, ATP release, aggregation, thromboxane B2 generation, clot retraction and procoagulant activity including phosphatidilserine exposure and microparticle formation, showed a statistically significant inhibition of thrombin-induced changes at pH of 7.0 and 6.5 compared to the physiological pH (7.4). The release of alpha granule content was differentially regulated by acidosis. At low pH, thrombin or collagen-induced secretion of vascular endothelial growth factor and endostatin were dramatically reduced. The release of von Willebrand factor and stromal derived factor-1α followed a similar, albeit less dramatic pattern. In contrast, the induction of CD40L was not changed by low pH, and P-selectin exposure was significantly increased. While the generation of mixed platelet-leukocyte aggregates and the increased chemotaxis of neutrophils mediated by platelets were further augmented under acidic conditions in a P-selectin dependent manner, the increased neutrophil survival was independent of P-selectin expression. In conclusion, our results indicate that extracellular acidosis downregulates most of the haemostatic platelet functions, and promotes those involved in amplifying the neutrophil-mediated inflammatory response.

  6. Changes in haematology measurements with the Sysmex XT-2000iV during storage of feline blood sampled in EDTA or EDTA plus CTAD.

    PubMed

    Granat, Fanny; Geffré, Anne; Bourgès-Abella, Nathalie; Braun, Jean-Pierre; Trumel, Catherine

    2013-06-01

    In veterinary medicine a complete blood cell count (CBC) cannot always be performed within 24 h as usually recommended, particularly for specimens shipped to a reference laboratory. This raises the question of the stability of the variables, especially in ethylenediamine tetra-acetic acid (EDTA) feline blood specimens, known to be prone to in vitro platelet aggregation. Citrate, theophylline, adenosine and dipyridamole (CTAD) has been reported to limit platelet aggregation in feline blood specimens. The aim of this study was to measure the stability of the haematological variables and the platelet aggregation score in EDTA and EDTA plus CTAD (EDCT) feline blood specimens during 48 h of storage at room temperature. Forty-six feline EDTA and EDCT blood specimens were analysed with a Sysmex XT-2000iV analyser, and the platelet count and score of platelet aggregation were estimated immediately and after 24 and 48 h of storage. A significant increase in mean corpuscular volume, haematocrit, reticulocyte and eosinophil counts, and a significant decrease in mean corpuscular haemoglobin concentration and monocyte count were observed. Haemoglobin, mean corpuscular haemoglobin, and red blood cell, white blood cell, neutrophil and lymphocyte counts remained stable. Changes in reticulocyte indexes with time (low fluorescence ratio, medium fluorescence ratio, high fluorescence ratio and immature reticulocyte fraction) were not significant. Changes were generally more pronounced in EDTA than in EDCT. Platelet aggregation decreased markedly in initially highly aggregated EDTA specimens, and increased slightly in initially non- or mildly-aggregated EDTA or EDCT specimens. Platelet counts increased and decreased, or remained stable, respectively. CTAD can reduce storage-induced changes of the haematological variables in feline samples, thus improving the reliability of a CBC and limiting clinical misinterpretations.

  7. 21 CFR 864.6675 - Platelet aggregometer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... shape and platelet aggregation following the addition of an aggregating reagent to a platelet rich... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Platelet aggregometer. 864.6675 Section 864.6675...) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6675 Platelet...

  8. 21 CFR 864.6675 - Platelet aggregometer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... shape and platelet aggregation following the addition of an aggregating reagent to a platelet rich... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Platelet aggregometer. 864.6675 Section 864.6675...) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6675 Platelet...

  9. 21 CFR 864.6675 - Platelet aggregometer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... shape and platelet aggregation following the addition of an aggregating reagent to a platelet rich... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Platelet aggregometer. 864.6675 Section 864.6675...) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6675 Platelet...

  10. 21 CFR 864.6675 - Platelet aggregometer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... shape and platelet aggregation following the addition of an aggregating reagent to a platelet rich... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Platelet aggregometer. 864.6675 Section 864.6675...) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6675 Platelet...

  11. 21 CFR 864.6675 - Platelet aggregometer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... shape and platelet aggregation following the addition of an aggregating reagent to a platelet rich... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Platelet aggregometer. 864.6675 Section 864.6675...) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6675 Platelet...

  12. Platelet Activation by Streptococcus pyogenes Leads to Entrapment in Platelet Aggregates, from Which Bacteria Subsequently Escape

    PubMed Central

    Svensson, Lisbeth; Baumgarten, Maria; Mörgelin, Matthias

    2014-01-01

    Platelet activation and aggregation have been reported to occur in response to a number of Gram-positive pathogens. Here, we show that platelet aggregates induced by Streptococcus pyogenes were unstable and that viable bacteria escaped from the aggregates over time. This was not due to differential activation in response to the bacteria compared with physiological activators. All the bacterial isolates induced significant platelet activation, including integrin activation and alpha and dense-granule release, at levels equivalent to those induced by potent physiological platelet activators that induced stable aggregates. The ability to escape the aggregates and to resist the antibacterial effects of platelets was dependent on active protein synthesis by the bacteria within the aggregate. We conclude that S. pyogenes bacteria can temporarily cover themselves with activated platelets, and we propose that this may facilitate survival of the bacteria in the presence of platelets. PMID:25069984

  13. Platelet activation in pregnancy-induced hypertension.

    PubMed

    Karalis, Ioannis; Nadar, Sunil K; Al Yemeni, Eman; Blann, Andrew D; Lip, Gregory Y H

    2005-01-01

    Although excess platelet activation, as indicated by increased plasma beta thromboglobulin (beta-TG), has been shown in pregnancy-induced hypertension (PIH), platelet adhesion, platelet morphology and a comparison of platelet and soluble (plasma) levels of the adhesion molecules P-selectin (pPsel and sPsel, respectively) have not been studied. We conducted a cross-sectional study of 35 consecutive women with PIH (age 31+/-6 years), 31 consecutive women with normotensive pregnancies (age 29+/-5 years) and 30 normotensive non pregnant women (age 30+/-5 years). Platelet adhesion was studied in vitro by binding to fibrinogen-coated microwells, platelet morphology [mass and volume by flow cytometry], whole-platelet P-selectin (pPsel) by ELISA of the lysate of 2 x 10(8) cells, and the plasma markers soluble P-selectin (sP-sel) and beta-TG, by ELISA. The women with PIH had significantly raised sPsel, pPsel and (as expected) beta-TG (all p<0.05), when compared to the normotensive pregnant women and controls. However, in PIH platelet adhesion was similar to that in the normotensive pregnancy, but still higher than the normal controls (p<0.001). There was no difference among the three groups with respect to platelet mass and volume. pPsel and platelet adhesion correlated with gestational age and with systolic and diastolic blood pressure (all p<0.05). Increased platelet activation and adhesion develop during normal pregnancy, with some indices being further altered in PIH.

  14. Autologous Platelet-Rich Plasma Preparations

    PubMed Central

    Schippinger, Gert; Prüller, Florian; Divjak, Manuela; Mahla, Elisabeth; Fankhauser, Florian; Rackemann, Steve; Raggam, Reinhard Bernd

    2015-01-01

    Background Autologous platelet-rich plasma (PRP) has been widely used for the treatment of sports injuries. It has been associated with improved healing and regeneration of soft tissues in elite athletes. Athletes are commonly receiving nonsteroidal anti-inflammatory drugs (NSAIDs). As yet, the effect of these drugs on platelet function in PRP formulations has not been taken into consideration. Hypothesis The function of platelets in PRP produced under the influence of NSAIDs is inhibited and may lessen a possible healing effect on the site of injury. Study Design Controlled laboratory study. Methods PRP was collected from patients receiving NSAIDs after elective orthopaedic surgery, and platelet function was evaluated using light transmission aggregometry (LTA). Results were compared with those obtained from healthy volunteers without a history of NSAID intake during the previous 2 weeks. Two different systems for blood collection and PRP production (Arthrex ACP double-syringe system and standard 4.5-mL sodium citrate blood collection tubes) were used and compared regarding the quality of PRP that was produced. Results For both groups, the baseline platelet counts of whole blood and the platelet counts of PRP formulations were found to be in the normal range. Both collection systems for PRP produced comparable results without significant differences between the groups. Platelet function testing with LTA revealed significantly impaired platelet aggregation in both PRP preparations, obtained from patients taking NSAIDs, irrespective of the type of NSAID (P < .001). All subjects from the control group showed normal platelet aggregation patterns when tested with LTA. Conclusion Autologous PRP produced from subjects after NSAID medication shows significantly impaired platelet function and may result in lower quality regarding the content of bioactive compounds. Clinical Relevance If required, the administration of NSAIDs should be performed after blood collection for

  15. Tocotrienols-induced inhibition of platelet thrombus formation and platelet aggregation in stenosed canine coronary arteries.

    PubMed

    Qureshi, Asaf A; Karpen, Charles W; Qureshi, Nilofer; Papasian, Christopher J; Morrison, David C; Folts, John D

    2011-04-14

    Dietary supplementation with tocotrienols has been shown to decrease the risk of coronary artery disease. Tocotrienols are plant-derived forms of vitamin E, which have potent anti-inflammatory, antioxidant, anticancer, hypocholesterolemic, and neuroprotective properties. Our objective in this study was to determine the extent to which tocotrienols inhibit platelet aggregation and reduce coronary thrombosis, a major risk factor for stroke in humans. The present study was carried out to determine the comparative effects of α-tocopherol, α-tocotrienol, or tocotrienol rich fraction (TRF; a mixture of α-+γ-+δ-tocotrienols) on in vivo platelet thrombosis and ex vivo platelet aggregation (PA) after intravenous injection in anesthetized dogs, by using a mechanically stenosed circumflex coronary artery model (Folts' cyclic flow model). Collagen-induced platelet aggregation (PA) in platelet rich plasma (PRP) was decreased markedly after treatment with α-tocotrienol (59%; P<0.001) and TRF (92%; P<0.001). α-Tocopherol treatment was less effective, producing only a 22% (P<0.05) decrease in PA. Adenosine diphosphate-induced (ADP) PA was also decreased after treatment with α-tocotrienol (34%; P<0.05) and TRF (42%; P<0.025). These results also indicate that intravenously administered tocotrienols were significantly better than tocopherols in inhibiting cyclic flow reductions (CFRs), a measure of the acute platelet-mediated thrombus formation. Tocotrienols (TRF) given intravenously (10 mg/kg), abolished CFRs after a mean of 68 min (range 22 -130 min), and this abolition of CFRs was sustained throughout the monitoring period (50-160 min).Next, pharmacokinetic studies were carried out and tocol levels in canine plasma and platelets were measured. As expected, α-Tocopherol treatment increased levels of total tocopherols in post- vs pre-treatment specimens (57 vs 18 μg/mL in plasma, and 42 vs 10 μg/mL in platelets). However, treatment with α-tocopherol resulted in slightly

  16. Tocotrienols-induced inhibition of platelet thrombus formation and platelet aggregation in stenosed canine coronary arteries

    PubMed Central

    2011-01-01

    Background Dietary supplementation with tocotrienols has been shown to decrease the risk of coronary artery disease. Tocotrienols are plant-derived forms of vitamin E, which have potent anti-inflammatory, antioxidant, anticancer, hypocholesterolemic, and neuroprotective properties. Our objective in this study was to determine the extent to which tocotrienols inhibit platelet aggregation and reduce coronary thrombosis, a major risk factor for stroke in humans. The present study was carried out to determine the comparative effects of α-tocopherol, α-tocotrienol, or tocotrienol rich fraction (TRF; a mixture of α- + γ- + δ-tocotrienols) on in vivo platelet thrombosis and ex vivo platelet aggregation (PA) after intravenous injection in anesthetized dogs, by using a mechanically stenosed circumflex coronary artery model (Folts' cyclic flow model). Results Collagen-induced platelet aggregation (PA) in platelet rich plasma (PRP) was decreased markedly after treatment with α-tocotrienol (59%; P < 0.001) and TRF (92%; P < 0.001). α-Tocopherol treatment was less effective, producing only a 22% (P < 0.05) decrease in PA. Adenosine diphosphate-induced (ADP) PA was also decreased after treatment with α-tocotrienol (34%; P < 0.05) and TRF (42%; P < 0.025). These results also indicate that intravenously administered tocotrienols were significantly better than tocopherols in inhibiting cyclic flow reductions (CFRs), a measure of the acute platelet-mediated thrombus formation. Tocotrienols (TRF) given intravenously (10 mg/kg), abolished CFRs after a mean of 68 min (range 22 -130 min), and this abolition of CFRs was sustained throughout the monitoring period (50 - 160 min). Next, pharmacokinetic studies were carried out and tocol levels in canine plasma and platelets were measured. As expected, α-Tocopherol treatment increased levels of total tocopherols in post- vs pre-treatment specimens (57 vs 18 μg/mL in plasma, and 42 vs 10 μg/mL in platelets). However, treatment with

  17. Relationship between platelet phospholipid FA and mean platelet volume in healthy men.

    PubMed

    Li, Duo; Turner, Alan; Sinclair, Andrew J

    2002-09-01

    Increased mean platelet volume (MPV) has been suggested as an independent risk factor for acute myocardial infarction and the increased reactivity of large platelets. The aim of this study was to investigate the correlation between platelet phospholipid (PL) PUFA composition and MPV in 139 free-living healthy men ages 20-55 yr (vegans, n = 18; ovolacto vegetarians, n = 43; moderate meat-eaters, n = 60; and high meateaters, n = 18). Each subject completed a semiquantitative Food Frequency Questionnaire and gave a blood sample. Platelet PL FA composition and MPV were determined by standard methods. MPV was significantly greater in the vegans than in the ovolacto vegetarian, moderate, or high meat-eater groups (P < 0.01). Both vegan and ovolacto vegetarian groups had significantly higher platelet PL 18:2n-6 and 22:4n-6, and lower 20:5n-3 and 22:6n-3 compared with the moderate and high meat-eater groups. The vegans demonstrated a significant reduction in 20:4n-6 and 22:5n-3 compared with the ovolacto vegetarian, high meat-eater, and moderate meat-eater groups. Bivariate analysis results showed that MPV was significantly positively correlated with platelet PL 18:2n-6 (P = 0.048) and negatively correlated with 20:3n-6 (P = 0.02), 20:5n-3 (P = 0.005), and 22:5n-3 (P< 0.0001), respectively. In a multiple linear regression analysis, after controlling for potential confounding factors such as dietary group, age, exercise, body mass index, and dietary polyunsaturated and saturated fat, cholesterol, carbohydrate, and fiber intake, the MPV was still strongly negatively correlated with platelet PL 20:3n-6 (P = 0.003) and 22:5n-3 (P = 0.001). The present data suggest that 22:5n-3 and 20:3n-6 may play a role in the structural function of the platelet membrane.

  18. Aerobic exercise training lowers platelet reactivity and improves platelet sensitivity to prostacyclin in pre- and postmenopausal women.

    PubMed

    Lundberg Slingsby, M H; Nyberg, M; Egelund, J; Mandrup, C M; Frikke-Schmidt, R; Kirkby, N S; Hellsten, Y

    2017-12-01

    Essentials It is unknown how regular exercise affects platelet function after menopause. We studied the effect of 3-months of high-intensity exercise in pre- and postmenopausal women. Platelet sensitivity to the inhibitory effect of arterially infused prostacyclin was increased. Reduced basal platelet reactivity was seen in the premenopausal women only. Background The risk of atherothrombotic events increases after the menopause. Regular physical activity has been shown to reduce platelet reactivity in younger women, but it is unknown how regular exercise affects platelet function after the menopause. Objectives To examine the effects of regular aerobic exercise in late premenopausal and recent postmenopausal women by testing basal platelet reactivity and platelet sensitivity to prostacyclin and nitric oxide. Methods Twenty-five sedentary, but healthy, late premenopausal and 24 matched recently postmenopausal women, mean (95% confidence interval) 49.1 (48.2-49.9) and 53.7 (52.5-55.0) years old, participated in an intervention study: 3-month high-intensity supervised aerobic spinning-cycle training (1 h, × 3/week). Basal platelet reactivity was analyzed in platelet-rich plasma from venous blood as agonist-induced % aggregation. In a subgroup of 13 premenopausal and 14 postmenopausal women, platelet reactivity was tested ex vivo after femoral arterial infusion of prostacyclin, acetylcholine, a cyclooxygenase inhibitor, and after acute one-leg knee extensor exercise. Results Basal platelet reactivity (%aggregation) to TRAP-6 (1 μm) was higher in the postmenopausal, 59% (50-68), than the premenopausal women, 45% (35-55). Exercise training reduced basal platelet reactivity to collagen (1 μg mL -1 ) in the premenopausal women only: from 63% (55-71%) to 51% (41-62%). After the training intervention, platelet aggregation was more inhibited by the arterial prostacyclin infusion and the acute exercise in both premenopausal and postmenopausal women. Conclusions These

  19. Platelets as delivery systems for disease treatments

    PubMed Central

    Shi, Qizhen; Montgomery, Robert R.

    2010-01-01

    Platelets are small, anucleate, discoid shaped blood cells that play a fundamental role in hemostasis. Platelets contain a large number of biologically active molecules within cytoplasmic granules that are critical to normal platelet function. Because platelets circulate in blood through out the body, release biological molecules and mediators on demand, and participate in hemostasis as well as many other pathophysiologic processes, targeting expression of proteins of interest to platelets and utilizing platelets as delivery systems for disease treatment would be a logical approach. This paper reviews the genetic therapy for inherited bleeding disorders utilizing platelets as delivery system, with a particular focus on platelet-derived FVIII for hemophilia A treatment. PMID:20619307

  20. Tendinopathies and platelet-rich plasma (PRP): from pre-clinical experiments to therapeutic use

    PubMed Central

    Kaux, Jean-François; Drion, Pierre; Croisier, Jean-Louis; Crielaard, Jean-Michel

    2015-01-01

    Objectives: The restorative properties of platelets, through the local release of growth factors, are used in various medical areas. This article reviews fundamental and clinical research relating to platelet-rich plasma applied to tendinous lesions. Materials and method: Articles in French and English, published between 1 January 2012 and 31 December 2014. dealing with PRP and tendons were searched for using the Medline and Scopus data bases. Results: Forty-seven articles were identified which addressed pre-clinical and clinical studies: 27 relating to in vitro and in vivo animal studies and 20 relating to human studies. Of these, five addressed lateral epicondylitis, two addressed rotator cuff tendinopathies, ten dealt with patellar tendinopathies and three looked at Achilles tendinopathies. Conclusions: The majority of pre-clinical studies show that PRP stimulates the tendon’s healing process. However, clinical series remain more controversial and level 1, controlled, randomised studies are still needed. PMID:26195890

  1. Aggregation and disaggregation kinetics of human blood platelets: Part II. Shear-induced platelet aggregation.

    PubMed Central

    Huang, P Y; Hellums, J D

    1993-01-01

    A population balance equation (PBE) mathematical model for analyzing platelet aggregation kinetics was developed in Part I (Huang, P. Y., and J. D. Hellums. 1993. Biophys. J. 65: 334-343) of a set of three papers. In this paper, Part II, platelet aggregation and related reactions are studied in the uniform, known shear stress field of a rotational viscometer, and interpreted by means of the model. Experimental determinations are made of the platelet-aggregate particle size distributions as they evolve in time under the aggregating influence of shear stress. The PBE model is shown to give good agreement with experimental determinations when either a reversible (aggregation and disaggregation) or an irreversible (no disaggregation) form of the model is used. This finding suggests that for the experimental conditions studied disaggregation processes are of only secondary importance. During shear-induced platelet aggregation, only a small fraction of platelet collisions result in the binding together of the involved platelets. The modified collision efficiency is approximately zero for shear rates below 3000 s-1. It increases with shear rates above 3000 s-1 to about 0.01 for a shear rate of 8000 s-1. Addition of platelet chemical agonists yields order of magnitude increases in collision efficiency. The collision efficiency for shear-induced platelet aggregation is about an order of magnitude less at 37 degrees C than at 24 degrees C. The PBE model gives a much more accurate representation of aggregation kinetics than an earlier model based on a monodispersed particle size distribution. PMID:8369442

  2. Assessment of canine autologous platelet-rich plasma produced with a commercial centrifugation and platelet recovery kit.

    PubMed

    Frye, Chris W; Enders, Andrew; Brooks, Marjory B; Struble, Angela M; Wakshlag, Joseph J

    2016-01-01

    To characterize the cellular composition (platelets, erythrocytes, and leukocytes) and confirm reproducibility of platelet enrichment, as well as determine the platelet activation status in the final product of a commercial platelet-rich plasma kit using canine blood. Venous blood from 20 sedated client-owned dogs was used to prepare platelet-rich plasma (PRP) from a commercial kit. Complete blood counts were performed to determine erythrocyte, leukocyte, and platelet numbers in both whole blood (WB) and resultant PRP. The WB and PRP samples from jugular (fast collection) and cephalic (slow collection) venipuncture were also compared. P-selectin externalization was measured in WB and PRP samples from 15 of 20 dogs. This commercial kit produced an average percent recovery in platelets of 64.7 ± 17.4; erythrocytes of 3.7 ± 0.8, and leukocytes of 31.6 ± 10.0. Neutrophil, monocyte, and lymphocyte percent recovery was 19.6 ± 7.2, 44.89 ± 19.8, and 57.5 ± 10.6, respectively. The recovery of platelets from jugular venipuncture (59.7 ± 13.6%) was lower than from cephalic recovery (68.8 ± 19.1%). The mean percent P-Selectin externalization for WB, PRP, and PRP with thrombin was 25.5 ± 30.9, 4.5 ± 6.4, and 90.6 ± 4.4 respectively. Cellular reproducibility of this kit was confirmed and platelets were concentrated within autologous serum. Additionally, measurements of P-selectin externalization showed that platelets are inactive in PRP unless stimulated to degranulate.

  3. Platelet-rich plasma in orthopedic therapy: a comparative systematic review of clinical and experimental data in equine and human musculoskeletal lesions.

    PubMed

    Brossi, Patrícia M; Moreira, Juliana J; Machado, Thaís S L; Baccarin, Raquel Y A

    2015-04-22

    This systematic review aimed to present and critically appraise the available information on the efficacy of platelet rich plasma (PRP) in equine and human orthopedic therapeutics and to verify the influence of study design and methodology on the assumption of PRP's efficacy. We searched Medline, PubMed, Embase, Bireme and Google Scholar without restrictions until July 2013. Randomized trials, human cohort clinical studies or case series with a control group on the use of PRP in tendons, ligaments or articular lesions were included. Equine clinical studies on the same topics were included independently of their design. Experimental studies relevant to the clarification of PRP's effects and mechanisms of action in tissues of interest, conducted in any animal species, were selected. This review included 123 studies. PRP's beneficial effects were observed in 46.7% of the clinical studies, while the absence of positive effects was observed in 43.3%. Among experimental studies, 73% yielded positive results, and 7.9% yielded negative results. The most frequent flaws in the clinical trials' designs were the lack of a true placebo group, poor product characterization, insufficient blinding, small sampling, short follow-up periods, and adoption of poor outcome measures. The methods employed for PRP preparation and administration and the selected outcome measures varied greatly. Poor study design was a common feature of equine clinical trials. From studies in which PRP had beneficial effects, 67.8% had an overall high risk of bias. From the studies in which PRP failed to exhibit beneficial effects, 67.8% had an overall low risk of bias. Most experimental studies revealed positive effects of PRP. Although the majority of equine clinical studies yielded positive results, the human clinical trials' results failed to corroborate these findings. In both species, beneficial results were more frequently observed in studies with a high risk of bias. The use of PRP in musculoskeletal

  4. Platelet count and platelet indices in women with preeclampsia.

    PubMed

    AlSheeha, Muneera A; Alaboudi, Rafi S; Alghasham, Mohammad A; Iqbal, Javed; Adam, Ishag

    2016-01-01

    Although the exact pathophysiology of preeclampsia is not completely understood, the utility of different platelets indices can be utilized to predict preeclampsia. To compare platelet indices, namely platelet count (PC), mean platelet volume (MPV), platelet distribution width (PDW), and PC to MPV ratio in women with preeclampsia compared with healthy controls. Qassim Hospital, Kingdom of Saudi Arabia. A case-control study. Sixty preeclamptic women were the cases and an equal number of healthy pregnant women were the controls. There was no significant difference in age, parity, and body mass index between the study groups. Sixteen and 44 of the cases were severe and mild preeclampsia, respectively. There was no significant difference in PDW and MPV between the preeclamptic and control women. Both PC and PC to MPV ratios were significantly lower in the women with preeclampsia compared with the controls. There was no significant difference in the PC, PDW, MPV, and PC to MPV ratio when women with mild and severe preeclampsia were compared. Using receiver operating characteristic (ROC) curves, the PC cutoff was 248.0×10 3 /µL for diagnosis of pre-eclampsia ( P =0.019; the area under the ROC curve was 62.4%). Binary regression suggests that women with PC <248.010×10 3 /µL were at higher risk of preeclampsia (odds ratio =2.2, 95% confidence interval =1.08-4.6, P =0.03). The PC/MPV cutoff was 31.2 for diagnosis of preeclampsia ( P =0.035, the area under the ROC curve was 62.2%). PC <248.010×10 3 /µL and PC to MPV ratio 31.2 are valid predictors of preeclampsia.

  5. Platelet Glycoprotein Ib-IX and Malignancy

    DTIC Science & Technology

    2010-09-01

    provide a unique microenvironment supporting the accumulation of more platelets and the elaboration of a fibrin - rich network produced by coagulation...process and can initiate the formation of a platelet - rich thrombus by tethering the platelet to a thrombogenic surface. Several ligands binding to GP Ib... Platelet Glycoprotein Ib-IX and Malignancy PRINCIPAL INVESTIGATOR: Jerry Ware, Ph.D

  6. Novel platelet substitutes: disk-shaped biodegradable nanosheets and their enhanced effects on platelet aggregation.

    PubMed

    Okamura, Yosuke; Fukui, Yoshihito; Kabata, Koki; Suzuki, Hidenori; Handa, Makoto; Ikeda, Yasuo; Takeoka, Shinji

    2009-10-21

    We have studied biocompatible spherical carriers carrying a dodecapeptide, HHLGGAKQAGDV (H12), on their surface as platelet substitutes. This peptide is a fibrinogen γ-chain carboxy-terminal sequence (γ400-411) and specifically recognizes the active form of glycoprotein IIb/IIIa on activated platelets. Our purpose is to assess the possibility of making a novel platelet substitute consisting of disk-shaped nanosheets having a large contact area for the targeting site, rather than conventional small contact area spherical carriers. The H12 peptide was conjugated to the surface of the free-standing nanosheets made of biodegradable poly(d,l-lactide-co-glycolide) (PLGA). These H12-PLGA nanosheets were fabricated onto 3 μm disk-shaped patterned hydrophobic octadecyl regions on a SiO(2) substrate. By way of comparison, spherical H12-PLGA microparticles with the same surface area and conjugation number of H12 were also prepared. The resulting H12-PLGA nanosheets specifically interacted with the activated platelets adhered on the collagen surface at twice the rate of the H12-PLGA microparticles under flow conditions, and showed platelet thrombus formation in a two-dimensional spreading manner. Thus, H12-PLGA nanosheets might be a suitable candidate novel platelet alternative substitute for infused human platelet concentrates for the treatment of bleeding in patients with severe thrombocytopenia.

  7. Platelet-rich preparations to improve healing. Part II: platelet activation and enrichment, leukocyte inclusion, and other selection criteria.

    PubMed

    Davis, Vicki L; Abukabda, Alaeddin B; Radio, Nicholas M; Witt-Enderby, Paula A; Clafshenkel, William P; Cairone, J Vito; Rutkowski, James L

    2014-08-01

    Multiple platelet-rich preparations have been reported to improve wound and bone healing, such as platelet-rich plasma (PRP) and platelet rich fibrin (PRF). The different methods employed during their preparation are important, as they influence the quality of the product applied to a wound or surgical site. Besides the general protocol for preparing the platelet-rich product (discussed in Part 1 of this review), multiple choices need to be considered during its preparation. For example, activation of the platelets is required for the release and enmeshment of growth factors, but the method of activation may influence the resulting matrix, growth factor availability, and healing. Additionally, some methods enrich leukocytes as well as platelets, but others are designed to be leukocyte-poor. Leukocytes have many important roles in healing and their inclusion in PRP results in increased platelet concentrations. Platelet and growth factor enrichment reported for the different types of platelet-rich preparations are also compared. Generally, TGF-β1 and PDGF levels were higher in preparations that contain leukocytes compared to leukocyte-poor PRP. However, platelet concentration may be the most reliable criterion for comparing different preparations. These and other criteria are described to help guide dental and medical professionals, in large and small practices, in selecting the best procedures for their patients. The healing benefits of platelet-rich preparations along with the low risk and availability of simple preparation procedures should encourage more clinicians to incorporate platelet-rich products in their practice to accelerate healing, reduce adverse events, and improve patient outcomes.

  8. Generation of Platelet Microparticles after Cryopreservation of Apheresis Platelet Concentrates Contributes to Hemostatic Activity.

    PubMed

    Eker, İbrahim; Yılmaz, Soner; Çetinkaya, Rıza Aytaç; Pekel, Aysel; Ünlü, Aytekin; Gürsel, Orhan; Yılmaz, Sebahattin; Avcu, Ferit; Muşabak, Uğur; Pekoğlu, Ahmet; Ertaş, Zerrin; Açıkel, Cengizhan; Zeybek, Nazif; Kürekçi, Ahmet Emin; Avcı, İsmail Yaşar

    2017-03-01

    In the last decade, substantial evidence has accumulated about the use of cryopreserved platelet concentrates, especially in trauma. However, little reference has been made in these studies to the morphological and functional changes of platelets. Recently platelets have been shown to be activated by cryopreservation processes and to undergo procoagulant membrane changes resulting in the generation of platelet-derived microparticles (PMPs), platelet degranulation, and release of platelet-derived growth factors (PDGFs). We assessed the viabilities and the PMP and PDGF levels of cryopreserved platelets, and their relation with thrombin generation. Apheresis platelet concentrates (APCs) from 20 donors were stored for 1 day and cryopreserved with 6% dimethyl sulfoxide. Cryopreserved APCs were kept at -80 °C for 1 day. Thawed APCs (100 mL) were diluted with 20 mL of autologous plasma and specimens were analyzed for viabilities and PMPs by flow cytometry, for thrombin generation by calibrated automated thrombogram, and for PDGFs by enzyme-linked immunosorbent assay testing. The mean PMP and PDGF levels in freeze-thawed APCs were significantly higher (2763±399.4/µL vs. 319.9±80.5/µL, p<0.001 and 550.9±73.6 pg/mL vs. 96.5±49 pg/mL, p<0.001, respectively), but the viability rates were significantly lower (68.2±13.7% vs. 94±7.5%, p<.001) than those of fresh APCs. The mean endogenous thrombin potential (ETP) of freeze-thawed APCs was significantly higher than that of the fresh APCs (3406.1±430.4 nM.min vs. 2757.6±485.7 nM.min, p<0.001). Moreover, there was a significant positive poor correlation between ETP levels and PMP levels (r=0.192, p=0.014). Our results showed that, after cryopreservation, while levels of PMPs were increasing, significantly higher and earlier thrombin formation was occurring in the samples analyzed despite the significant decrease in viability. Considering the damage caused by the freezing process and the scarcity of evidence for their in

  9. Platelets from patients with the Quebec platelet disorder contain and secrete abnormal amounts of urokinase-type plasminogen activator.

    PubMed

    Kahr, W H; Zheng, S; Sheth, P M; Pai, M; Cowie, A; Bouchard, M; Podor, T J; Rivard, G E; Hayward, C P

    2001-07-15

    The Quebec platelet disorder (QPD) is an autosomal dominant platelet disorder associated with delayed bleeding and alpha-granule protein degradation. The degradation of alpha-granule, but not plasma, fibrinogen in patients with the QPD led to the investigation of their platelets for a protease defect. Unlike normal platelets, QPD platelets contained large amounts of fibrinolytic serine proteases that had properties of plasminogen activators. Western blot analysis, zymography, and immunodepletion experiments indicated this was because QPD platelets contained large amounts of urokinase-type plasminogen activator (u-PA) within a secretory compartment. u-PA antigen was not increased in all QPD plasmas, whereas it was increased more than 100-fold in QPD platelets (P <.00009), which contained increased u-PA messenger RNA. Although QPD platelets contained 2-fold more plasminogen activator inhibitor 1 (PAI-1) (P <.0008) and 100-fold greater u-PA-PAI-1 complexes (P <.0002) than normal platelets, they contained excess u-PA activity, predominantly in the form of two chain (tcu-PA), which required additional PAI-1 for full inhibition. There was associated proteolysis of plasminogen in QPD platelets, to forms that comigrated with plasmin. When similar amounts of tcu-PA were incubated with normal platelet secretory proteins, many alpha-granule proteins were proteolyzed to forms that resembled degraded QPD platelet proteins. These data implicate u-PA in the pathogenesis of alpha-granule protein degradation in the QPD. Although patients with the QPD have normal to increased u-PA levels in their plasma, without evidence of systemic fibrinogenolysis, their increased platelet u-PA could contribute to bleeding by accelerating fibrinolysis within the hemostatic plug. QPD is the only inherited bleeding disorder in humans known to be associated with increased u-PA.

  10. Intrinsic platelet reactivity before start with clopidogrel as predictor for on-clopidogrel platelet function and long-term clinical outcome.

    PubMed

    Hochholzer, Willibald; Valina, Christian M; Bömicke, Timo; Amann, Michael; Stratz, Christian; Nührenberg, Thomas; Trenk, Dietmar; Neumann, Franz-Josef

    2015-07-01

    High on-clopidogrel platelet reactivity is associated with worse clinical outcome. Previous data suggest that intrinsic platelet reactivity before initiation of clopidogrel contributes significantly to on-clopidogrel platelet reactivity. It is unknown whether intrinsic reactivity can sufficiently predict on-clopidogrel reactivity and therefore identify patients with insufficient response to clopidogrel before initiation of treatment and at risk for worse clinical outcome. This analysis included 765 consecutive patients undergoing elective coronary stent implantation. Platelet reactivity was assessed by light transmission aggregometry (5 µM ADP) before administration of clopidogrel 600mg and after intake of first maintenance dose of clopidogrel on day 1 following coronary stenting. Patients were followed for up to seven years. The combined primary endpoint was death of any cause or non-fatal myocardial infarction. Intrinsic and on-clopidogrel platelet reactivity were significant correlated (r=0.31; p < 0.001). Among all tested clinical and genetic factors including the cytochrome P450 2C19*2 polymorphism, intrinsic platelet reactivity was the strongest predictor for on-clopidogrel platelet reactivity. However, intrinsic platelet reactivity could only explain 8 % of variability of on-clopidogrel platelet function. Only on-treatment platelet reactivity was predictive for long-term clinical outcome (HR 1.47, 95 % CI 1.05-2.05; p = 0.02) whereas intrinsic platelet reactivity was not (HR 1.03, 95 % CI 0.74-1.43; p = 0.86). In conclusion, intrinsic platelet reactivity before initiation of clopidogrel is the strongest predictor of early on-clopidogrel platelet reactivity but can only explain a minor proportion of its variability and is not significantly associated with clinical outcome. Thus, baseline testing cannot substitute on-clopidogrel platelet function testing.

  11. Pathogen-Reduced, Platelet Additive Solution, Extended Stored Platelets (PREPS)

    DTIC Science & Technology

    2015-10-01

    Sherrill J. Slichter, MD CONTRACTING ORGANIZATION: Bloodworks Northwest Seattle, WA 98104 REPORT DATE : October 2015 TYPE OF REPORT: Annual...NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE October 2015 2. REPORT TYPE Annual 3. DATES COVERED 15-SEP-14 to 14-SEP-15 4. TITLE AND...accomplishments to date . Brrr Study Our study of platelets stored as whole blood at 4°C demonstrated that end-over-end rotation is required to reduce platelet

  12. Characteristics of platelet gels combined with silk

    PubMed Central

    Pallotta, Isabella; Kluge, Jonathan A.; Moreau, Jodie; Calabrese, Rossella

    2014-01-01

    Platelet gel, a fibrin network containing activated platelets, is widely used in regenerative medicine due the capacity of platelet-derived growth factors to accelerate and direct healing processes. However, limitations to this approach include poor mechanical properties, relatively rapid degradation, and the lack of control of release of growth factors at the site of injection. These issues compromise the ability of platelet gels for sustained function in regenerative medicine. In the present study, a combination of platelet gels with silk fibroin gel was studied to address the above limitations. Mixing sonicated silk gels with platelet gels extended the release of growth factors without inhibiting gel forming ability. The released growth factors were biologically active and their delivery was modified further by manipulation of the charge of the silk protein. Moreover, the silk gel augmented both the rheological properties and compressive stiffness of the platelet gel, tuned by the silk concentration and/or silk/platelet gel ratio. Silk-platelet gel injections in nude rats supported enhanced cell infiltration and blood vessel formation representing a step towards new platelet gel formulations with enhanced therapeutic impact. PMID:24480538

  13. Acquired platelet function defect

    MedlinePlus

    ... Some cases cannot be prevented. Alternative Names Acquired qualitative platelet disorders; Acquired disorders of platelet function Images ... Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare ...

  14. Platelet microparticles: detection and assessment of their paradoxical functional roles in disease and regenerative medicine.

    PubMed

    Burnouf, Thierry; Goubran, Hadi Alphonse; Chou, Ming-Li; Devos, David; Radosevic, Mirjana

    2014-07-01

    There is increasing research on and clinical interest in the physiological role played by platelet microparticles (PMPs). PMPs are 0.1-1-μm fragments shed from plasma membranes of platelets that are undergoing activation, stress, or apoptosis. They have a phospholipid-based structure and express functional receptors from platelet membranes. As they are the most abundant microparticles in the blood and they express the procoagulant phosphatidylserine, PMPs likely complement, if not amplify, the functions of platelets in hemostasis, thrombosis, cancer, and inflammation, but also act as promoters of tissue regeneration. Their size and structure make them instrumental in platelet-cell communications as a delivery tool of platelet-borne bioactive molecules including growth factors, other signaling molecules and micro (mi)RNA. PMPs can therefore be a pathophysiological threat or benefit to the cellular environment when interacting with the blood vasculature. There is also increasing evidence that PMP generation is triggered during blood collection, separation into components, and storage, a phenomenon potentially leading to thrombotic and inflammatory side effects in transfused patients. Evaluating PMPs requires strict pre-analytical and analytical procedures to avoid artifactual generation and ensure accurate assessment of the number, size repartitioning, and functional properties. This review describes the physical and functional methods developed for analyzing and quantifying PMPs. It then presents the functional roles of PMPs as markers or triggers of diseases like thrombosis, atherosclerosis, and cancer, and discusses the possible detrimental immunological impact of their generation in blood components. Finally we review the potential function of PMPs in tissue regeneration and the prospects for their use in therapeutic strategies for human health. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Gallic Acid Attenuates Platelet Activation and Platelet-Leukocyte Aggregation: Involving Pathways of Akt and GSK3β

    PubMed Central

    Chang, Shih-Sheng; Lee, Viola S. Y.; Tseng, Yu-Lun; Chang, Kuan-Cheng; Chen, Kuen-Bao; Chen, Yuh-Lien; Li, Chi-Yuan

    2012-01-01

    Platelet activation and its interaction with leukocytes play an important role in atherothrombosis. Cardiovascular diseases resulted from atherothrombosis remain the major causes of death worldwide. Gallic acid, a major constituent of red wine and tea, has been believed to have properties of cardiovascular protection, which is likely to be related to its antioxidant effects. Nonetheless, there were few and inconsistent data regarding the effects of gallic acid on platelet function. Therefore, we designed this in vitro study to determine whether gallic acid could inhibit platelet activation and the possible mechanisms. From our results, gallic acid could concentration-dependently inhibit platelet aggregation, P-selectin expression, and platelet-leukocyte aggregation. Gallic acid prevented the elevation of intracellular calcium and attenuated phosphorylation of PKCα/p38 MAPK and Akt/GSK3β on platelets stimulated by the stimulants ADP or U46619. This is the first mechanistic explanation for the inhibitory effects on platelets from gallic acid. PMID:22811749

  16. Assessment of platelet function in healthy sedated cats using three whole blood platelet function tests.

    PubMed

    Ho, Kimberly K; Abrams-Ogg, Anthony C G; Wood, R Darren; O'Sullivan, M Lynne; Kirby, Gordon M; Blois, Shauna L

    2015-05-01

    The objectives of this study were to establish feline references intervals for 3 commercial whole blood platelet function test analyzer systems: Multiplate analyzer (MP; Roche Diagnostics International Ltd., Rotkreuz, Switzerland), Platelet Function Analyzer-100 (PF: Siemens Canada, Mississauga, Ontario, Canada), and Plateletworks Combo-25 kit (PW; Helena Laboratories, Beaumont, TX). Venipuncture was performed on 55 healthy sedated cats, and platelet aggregation in response to adenosine diphosphate (ADP), collagen (COL), and arachidonic acid (AA; MP only) was assessed using citrated blood. For the MP analyzer, median (95% confidence intervals [CIs]) area under curve (Units) for ADP, COL, and AA agonists were 87 (11-176), 81 (32-129), and 91 (59-129), respectively. For the PF analyzer, median (95% CIs) closure time, using COL-ADP cartridges, was 69 (46-89) sec. For the PW assay, median (95% CIs) percent aggregations for ADP and COL agonists were 71 (18-92) and 49 (9-96), respectively, using impedance hematology analyzer platelet counts, and 94 (25-98) and 68 (14-119), respectively, using flow cytometry hematology analyzer platelet counts. There were low correlations between the PF analyzer (COL-ADP cartridge) and MP analyzer (COL agonist; ρ = 0.11), and between the PF analyzer (COL-ADP cartridge) and PW assay (COL agonist using impedance platelet counts; ρ = 0.14). The PW assay percent aggregations using impedance and flow cytometric platelet counts were correlated for both ADP (ρ = 0.64) and COL (ρ = 0.64) agonists. Platelet function testing using these tests are feasible in cats, but 95% CIs are wide, so single results may be difficult to interpret. Platelet counting by impedance or flow cytometry may be used for the PW assay but are not interchangeable. © 2015 The Author(s).

  17. Clinical significance of residual platelet reactivity in patients treated with platelet P2Y12 inhibitors.

    PubMed

    Thomas, Mark R; Storey, Robert F

    2016-09-01

    Platelet P2Y12 inhibitors have become an essential component of the treatment strategy for patients with acute coronary syndromes and patients undergoing percutaneous coronary intervention. It is now well-established that approximately 30% of patients treated with the P2Y12 inhibitor clopidogrel display high residual platelet reactivity despite treatment. Patients with high on-treatment platelet reactivity have approximately 2-3-fold greater risk of adverse cardiovascular events and stent thrombosis than those without high platelet reactivity. Conversely, clopidogrel-treated patients with low platelet reactivity display approximately 1.7-fold increased risk of major bleeding. High platelet reactivity is uncommon during treatment with prasugrel and ticagrelor, which achieve a greater reduction in adverse cardiovascular events compared to clopidogrel in ACS patients treated with PCI. This is at the expense of an increase in spontaneous bleeding, however. Minor bleeding events, such as skin haematomas, are more common in prasugrel- and ticagrelor-treated patients that have particularly low platelet reactivity values. These minor bleeding events may occasionally prompt discontinuation of therapy, but their overall prognostic impact is uncertain. However, risk factors for bleeding tend to overlap with risk factors for adverse cardiovascular events. Therefore, patients with these minor bleeding events may also be at higher risk of adverse cardiovascular events, conferring a benefit from low platelet reactivity. Further work is needed to determine the optimal level of platelet reactivity in individuals by taking into account their risk of subsequent adverse cardiovascular events and bleeding. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Spore-forming organisms in platelet concentrates: a challenge in transfusion bacterial safety.

    PubMed

    Störmer, M; Vollmer, T; Kleesiek, K; Dreier, J

    2008-12-01

    Bacterial detection and pathogen reduction are widely used methods of minimizing the risk of transfusion-transmitted bacterial infection. But, bacterial spores are highly resistant to chemical and physical agents. In this study, we assessed the bacterial proliferation of spore-forming organisms seeded into platelet concentrates (PCs) to demonstrate that spores can enter the vegetative state in PCs during storage. In the in vitro study, PCs were inoculated with 1-10 spores mL(-1)of Bacillus cereus (n = 1), Bacillus subtilis (n = 2) and Clostridium sporogenes (n = 2). Sampling was performed during 6-day aerobic storage at 22 degrees C. The presence of bacteria was assessed by plating culture, automated culture and real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Spores of the C. sporogenes do not enter the vegetative phase under PC storage conditions, whereas B. subtilis and B. cereus showed growth in the PC and could be detected using RT-PCR and automated culture. Depending on the species and inoculums, bacterial spores may enter the vegetative phase during PC storage and can be detected by bacterial detection methods.

  19. Insufficient platelet inhibition is related to silent embolic cerebral infarctions after coronary angiography.

    PubMed

    Kim, Bum Joon; Lee, Seung-Whan; Park, Seong-Wook; Kang, Dong-Wha; Kim, Jong S; Kwon, Sun U

    2012-03-01

    Considering that insufficient platelet inhibition is related to thrombotic complications after coronary angiography, we hypothesized that the extent of platelet inhibition by antiplatelet agents is related to the occurrence of silent embolic cerebral infarction (SECI) after coronary angiography. Among the patients scheduled for coronary artery bypass surgery, we retrospectively analyzed the location of SECI on diffusion-weighted imaging of 272 patients, which was performed after coronary angiography, as a presurgical evaluation in Phase 1 study. In Phase 2 study, we have prospectively recruited 102 patients to compare the extent of platelet inhibition measured by the VerifyNow system among patients with and without SECI. SECI is observed in 45 patients (16.5%) in Phase 1 and 17 (16.7%) in Phase 2. The lesions were slightly more frequent in the right hemisphere. In the Phase 2 study, aspirin reaction units and P(2)Y(12) reaction units were higher in the patients with SECI than those without (aspirin reaction units: 490±72 versus 446±53, P=0.03; P(2)Y(12) reaction units: 352±65 versus 300±77, P=0.009). The incidence of SECI increased with the number of resistant antiplatelets; resistance to both antiplatelet agent (50%), resistance to 1 antiplatelet agent (22%), and no resistance (4%; P=0.023). From the result of logistic regression, higher aspirin reaction units, white blood cell count, low hemoglobin, and nonresponsiveness to antiplatelet agents were independent risk factors. Insufficient platelet inhibition after administration of antiplatelet agents is related with SECI appearing after coronary angiography.

  20. Platelet cyclooxygenase expression in normal dogs.

    PubMed

    Thomason, J; Lunsford, K; Mullins, K; Stokes, J; Pinchuk, L; Wills, R; McLaughlin, R; Langston, C; Pruett, S; Mackin, A

    2011-01-01

    Human platelets express both cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2). Variation in COX-2 expression could be a mechanism for variable response to aspirin. The hypotheses were that circulating canine platelets express COX-1 and COX-2, and that aspirin alters COX expression. The objective was to identify changes in platelet COX expression and in platelet function caused by aspirin administration to dogs. Eight female, intact hounds. A single population, repeated measures design was used to evaluate platelet COX-1 and COX-2 expression by flow cytometry before and after aspirin (10 mg/kg Q12h for 10 days). Platelet function was analyzed via PFA-100(®) (collagen/epinephrine), and urine 11-dehydro-thromboxane B(2) (11-dTXB(2)) was measured and normalized to urinary creatinine. Differences in COX expression, PFA-100(®) closure times, and urine 11-dTXB(2 ): creatinine ratio were analyzed before and after aspirin administration. Both COX-1 and COX-2 were expressed in canine platelets. COX-1 mean fluorescent intensity (MFI) increased in all dogs, by 250% (range 63-476%), while COX-2 expression did not change significantly (P = 0.124) after aspirin exposure, with large interindividual variation. PFA-100(®) closure times were prolonged and urine 11-dTXB(2) concentration decreased in all dogs after aspirin administration. Canine platelets express both COX isoforms. After aspirin exposure, COX-1 expression increased despite impairment of platelet function, while COX-2 expression varied markedly among dogs. Variability in platelet COX-2 expression should be explored as a potential mechanism for, or marker of, variable aspirin responsiveness. Copyright © 2011 by the American College of Veterinary Internal Medicine.

  1. Peri-Procedural Platelet Reactivity in Percutaneous Coronary Intervention.

    PubMed

    Alexopoulos, Dimitrios; Xenogiannis, Iosif; Vlachakis, Panagiotis; Tantry, Udaya; Gurbel, Paul A

    2018-06-04

    Platelet activation and aggregation play a pivotal role in thrombotic complications occurring during percutaneous coronary intervention (PCI), and peri-PCI anti-platelet therapy represents a standard of care. High platelet reactivity prior to PCI has been correlated with an increased incidence of peri-procedural myonecrosis. Pre-PCI platelet reactivity predicts post-PCI platelet reactivity and has a prognostic impact on subsequent ischaemic and bleeding events, so as the platelet inhibition measured post-PCI. Many anti-platelet treatment strategies, including aspirin, glycoprotein IIb/IIIa inhibitors, P2Y 12 receptor blockers and vorapaxar, are being used in the routine clinical practice to modify platelet reactivity at each stage, e.g. pre-, during and post-PCI. Anti-platelet strategies with a 'stronger and faster' pharmacodynamic effect than clopidogrel have been mostly adopted in patients with acute coronary syndromes. However, several issues regarding the anti-platelet treatment such as benefits/risks of anti-platelet therapy pre-treatment and duration, and definite association between speed and potency of various anti-platelet agents and clinical outcomes remain controversial. We believe that a better understanding of peri-PCI platelet reactivity and its relations to outcomes may lead to the development of more effective and safe treatment strategies. Schattauer GmbH Stuttgart.

  2. Peptide-Mediated Platelet Capture at Gold Micropore Arrays.

    PubMed

    Adamson, Kellie; Spain, Elaine; Prendergast, Una; Moran, Niamh; Forster, Robert J; Keyes, Tia E

    2016-11-30

    Ordered spherical cap gold cavity arrays with 5.4, 1.6, and 0.98 μm diameter apertures were explored as capture surfaces for human blood platelets to investigate the impact of surface geometry and chemical modification on platelet capture efficiency and their potential as platforms for surface enhanced Raman spectroscopy of single platelets. The substrates were chemically modified with single-constituent self-assembled monolayers (SAM) or mixed SAMs comprised of thiol-functionalized arginine-glycine-aspartic acid (RGD, a platelet integrin target) with or without 1-octanethiol (adhesion inhibitor). As expected, platelet adhesion was promoted and inhibited at RGD and alkanethiol modified surfaces, respectively. Platelet adhesion was reversible, and binding efficiency at the peptide modified substrates correlated inversely with pore diameter. Captured platelets underwent morphological change on capture, the extent of which depended on the topology of the underlying substrate. Regioselective capture of the platelets enabled study for the first time of the surface enhanced Raman spectroscopy of single blood platelets, yielding high quality Raman spectroscopy of individual platelets at 1.6 μm diameter pore arrays. Given the medical importance of blood platelets across a range of diseases from cancer to psychiatric illness, such approaches to platelet capture may provide a useful route to Raman spectroscopy for platelet related diagnostics.

  3. Novel whole blood assay for phenotyping platelet reactivity in mice identifies ICAM-1 as a mediator of platelet-monocyte interaction

    PubMed Central

    Kirkby, Nicholas S.; Chan, Melissa V.; Finsterbusch, Michaela; Hogg, Nancy; Nourshargh, Sussan; Warner, Timothy D.

    2015-01-01

    Testing of platelet function is central to the cardiovascular phenotyping of genetically modified mice. Traditional platelet function tests have been developed primarily for testing human samples and the volumes required make them highly unsuitable for the testing of mouse platelets. This limits research in this area. To address this problem, we have developed a miniaturized whole blood aggregometry assay, based on a readily accessible 96-well plate format coupled with quantification of single platelet depletion by flow cytometric analysis. Using this approach, we observed a concentration-dependent loss of single platelets in blood exposed to arachidonic acid, collagen, U46619 or protease activated receptor 4 activating peptide. This loss was sensitive to well-established antiplatelet agents and genetic manipulation of platelet activation pathways. Observations were more deeply analyzed by flow cytometric imaging, confocal imaging, and measurement of platelet releasates. Phenotypic analysis of the reactivity of platelets taken from mice lacking intercellular adhesion molecule (ICAM)-1 identified a marked decrease in fibrinogen-dependent platelet-monocyte interactions, especially under inflammatory conditions. Such findings exemplify the value of screening platelet phenotypes of genetically modified mice and shed further light upon the roles and interactions of platelets in inflammation. PMID:26215112

  4. Platelet morphology, soluble P selectin and platelet P-selectin in acute ischaemic stroke. The West Birmingham Stroke Project.

    PubMed

    Nadar, Sunil K; Lip, Gregory Y H; Blann, Andrew D

    2004-12-01

    The pathophysiology of ischaemic stroke involves the platelet. In this study, we hypothesised that abnormalities in platelet morphology, as well as soluble (sPsel) and total platelet P-selectin (pPsel) levels would be present in patients presenting with an acute ischaemic stroke, and that these changes would improve at > or = 3 months' follow-up. We studied 59 hypertensive patients (34 male; mean age 68 +/- 12 years) who presented with an acute ischaemic stroke (ictus < 24 hours), and compared them with 2 groups: (i) age-, sex- and ethnic- origin matched normotensive healthy controls; and (ii) uncomplicated 'high risk' hypertensive patients as 'risk factor control' subjects. Platelet morphology (volume and mass) was quantified, and sPsel (plasma marker of platelet activation) was measured (ELISA) in citrated plasma. The mass of P-selectin in each platelet (pPsel) was determined by lysing a fixed number of platelets and then determining the levels of P-selectin in the lysate. Results show that patients who presented with a stroke had significantly higher levels of sPsel and pPsel (both p < 0.001), compared to the normal controls and the hypertensive patients. Patients with an acute stroke had lower mean platelet mass (MPM) and mean platelet volume (MPV) as compared to the uncomplicated hypertensive patients, who had significantly higher mean MPM and MPV values, as compared to normal controls. On follow-up, the levels of both sPsel (p = 0.011), pPsel (< 0.001) and MPV (p = 0.03) were significantly lower. Mean MPM levels remained unchanged. We conclude that patients presenting with an acute ischaemic stroke have activated platelets, as evident by the increased levels of soluble and platelet P-selectin. Further study of platelet activation and the role of P-selectin is warranted.

  5. Regulating billions of blood platelets: glycans and beyond

    PubMed Central

    Grozovsky, Renata; Giannini, Silvia; Falet, Hervé

    2015-01-01

    The human body produces and removes 1011 platelets daily to maintain a normal steady state platelet count. Platelet production must be regulated to avoid spontaneous bleeding or arterial occlusion and organ damage. Multifaceted and complex mechanisms control platelet production and removal in physiological and pathological conditions. This review will focus on different mechanisms of platelet senescence and clearance with specific emphasis on the role of posttranslational modifications. It will also briefly address platelet transfusion and the role of glycans in the clearance of stored platelets. PMID:26330242

  6. Systems biology of stored blood cells: can it help to extend the expiration date?

    PubMed

    Paglia, Giuseppe; Palsson, Bernhard Ø; Sigurjonsson, Olafur E

    2012-12-05

    With increasingly stringent regulations regarding deferral and elimination of blood donors it will become increasingly important to extend the expiration date of blood components beyond the current allowed storage periods. One reason for the storage time limit for blood components is that platelets and red blood cells develop a condition called storage lesions during their storage in plastic blood containers. Systems biology provides comprehensive bio-chemical descriptions of organisms through quantitative measurements and data integration in mathematical models. The biological knowledge for a target organism can be translated in a mathematical format and used to compute physiological properties. The use of systems biology represents a concrete solution in the study of blood cell storage lesions, and it may open up new avenues towards developing better storage methods and better storage media, thereby extending the storage period of blood components. This article is part of a Special Issue entitled: Integrated omics. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Effect of photodynamic therapy on mouse platelets

    NASA Astrophysics Data System (ADS)

    Zhou, Chuannong; Chi, Shunji; Deng, Jinsheng; Zhang, Hua; Liang, Junlin; Ha, Xian-wen

    1993-06-01

    Normal mice received hematoporphyrin derivative (HpD) i.v. prior to red light irradiation and the platelet-rich plasma was prepared and irradiated by red light. The platelets were processed for EM examination and stereological analysis. It was shown the 16 hrs after irradiation almost all platelets were necrotized; 8 hours after irradiation about one fourth of the platelets were necrotized and the remaining were considerably damaged. Immediately after irradiation a small number of platelets became necrotic and most other platelets were swollen and deformated, showing significantly increased mean area, perimeter and short axis, and mean cell volume and cell surface area. The findings indicate that platelets are highly sensitive to PDT action and can be directly and rapidly damaged by PDT even in the absence of vascular endothelial cells. The early platelet photoactivation may play an important role in the initiation of early vascular damage and microcirculatory alterations induced by PDT in vivo.

  8. Mechanism of platelet functional changes and effects of anti-platelet agents on in vivo hemostasis under different gravity conditions.

    PubMed

    Li, Suping; Shi, Quanwei; Liu, Guanglei; Zhang, Weilin; Wang, Zhicheng; Wang, Yuedan; Dai, Kesheng

    2010-05-01

    Serious thrombotic and hemorrhagic problems or even fatalities evoked by either microgravity or hypergravity occur commonly in the world. We recently reported that platelet functions are inhibited in microgravity environments and activated under high-G conditions, which reveals the pathogenesis for gravity change-related hemorrhagic and thrombotic diseases. However, the mechanisms of platelet functional variations under different gravity conditions remain unclear. In this study we show that the amount of filamin A coimmunoprecipitated with GPIbalpha was enhanced in platelets exposed to modeled microgravity and, in contrast, was reduced in 8 G-exposed platelets. Hypergravity induced actin filament formation and redistribution, whereas actin filaments were reduced in platelets treated with modeled microgravity. Furthermore, intracellular Ca2+ levels were elevated by hypergravity. Pretreatment of platelets with the cell-permeable Ca2+ chelator BAPTA-AM had no effect on cytoskeleton reorganization induced by hypergravity but significantly reduced platelet aggregation induced by ristocetin/hypergravity. Two anti-platelet agents, aspirin and tirofiban, effectively reversed the shortened tail bleeding time and reduced the death rate of mice exposed to hypergravity. Furthermore, the increased P-selectin surface expression was obviously reduced in platelets from mice treated with aspirin/hypergravity compared with those from mice treated with hypergravity alone. These data suggest that the actin cytoskeleton reorganization and intracellular Ca2+ level play key roles in the regulation of platelet functions in different gravitational environments. The results with anti-platelet agents not only further confirm the activation of platelets in vivo but also suggest a therapeutic potential for hypergravity-induced thrombotic diseases.

  9. Use of photoactivated disinfection and platelet-rich fibrin in regenerative Endodontics

    PubMed Central

    Johns, Dexton Antony; Shivashankar, Vasundara Yayathi; Krishnamma, Shoba; Johns, Manu

    2014-01-01

    Aim: Photoactivated disinfection has been used as an adjunct to conventional endodontic treatment. Its use in regenerative endodontics is not reported in literature. The aim of this case report was to describe a new proposal for pulp revascularization with disinfection of pulp canal space using a unique combination of a photosensitizer solution and low-power laser light. Materials and Methods: A 9-year-old boy came with the chief complaint of discolored upper central incisors (#8, #9). A diagnosis of pulp necrosis was made on the basis of clinical and radiographic findings. The canal was irrigated with 5.25% sodium hypochlorite solution and dried with paper points. Photodynamic therapy was used to disinfect the root canal and platelet-rich fibrin was used to revitalize the pulp. Three millimeters of gray mineral trioxide aggregate was placed directly over the platelet-rich plasma clot. Three days later, the tooth was double-sealed with permanent filling materials. Results: Clinical examination revealed no sensitivity to percussion or palpation tests. Radiograph revealed continued thickening of the dentinal walls, root lengthening, regression of the peri-apical lesion and apical closure. Both the roots showed complete apical closure at the 10-month follow-up. However, the teeth were not responsive to electric pulp test. Conclusion: This report of pulp revascularization shows that disinfection with photodynamic therapy combined with platelet-rich fibrin leads to satisfactory root development in necrotic immature teeth. PMID:25298655

  10. Investigations of human platelet-type 12-lipoxygenase: role of lipoxygenase products in platelet activation1[S

    PubMed Central

    Ikei, Kenneth N.; Yeung, Jennifer; Apopa, Patrick L.; Ceja, Jesús; Vesci, Joanne; Holinstat, Michael

    2012-01-01

    Human platelet-type 12-lipoxygenase (12-LOX) has recently been shown to play an important role in regulation of human platelet function by reacting with arachidonic acid (AA). However, a number of other fatty acids are present on the platelet surface that, when cleaved from the phospholipid, can be oxidized by 12-LOX. We sought to characterize the substrate specificity of 12-LOX against six essential fatty acids: AA, dihomo-γ-linolenic acid (DGLA), eicosapentaenoic acid (EPA), α-linolenic acid (ALA), eicosadienoic acid (EDA), and linoleic acid (LA). Three fatty acids were comparable substrates (AA, DGLA, and EPA), one was 5-fold slower (ALA), and two showed no reactivity with 12-LOX (EDA and LA). The bioactive lipid products resulting from 12-LOX oxidation of DGLA, 12-(S)-hydroperoxy-8Z,10E,14Z-eicosatrienoic acid [12(S)-HPETrE], and its reduced product, 12(S)-HETrE, resulted in significant attenuation of agonist-mediated platelet aggregation, granule secretion, αIIbβ3 activation, Rap1 activation, and clot retraction. Treatment with DGLA similarly inhibited PAR1-mediated platelet activation as well as platelet clot retraction. These observations are in surprising contrast to our recent work showing 12(S)-HETE is a prothrombotic bioactive lipid and support our hypothesis that the overall effect of 12-LOX oxidation of fatty acids in the platelet is dependent on the fatty acid substrates available at the platelet membrane. PMID:22984144

  11. Coated platelets function in platelet-dependent fibrin formation via integrin αIIbβ3 and transglutaminase factor XIII

    PubMed Central

    Mattheij, Nadine J.A.; Swieringa, Frauke; Mastenbroek, Tom G.; Berny-Lang, Michelle A.; May, Frauke; Baaten, Constance C.F.M.J.; van der Meijden, Paola E.J.; Henskens, Yvonne M.C.; Beckers, Erik A.M.; Suylen, Dennis P.L.; Nolte, Marc W.; Hackeng, Tilman M.; McCarty, Owen J.T.; Heemskerk, Johan W.M.; Cosemans, Judith M.E.M.

    2016-01-01

    Coated platelets, formed by collagen and thrombin activation, have been characterized in different ways: i) by the formation of a protein coat of α-granular proteins; ii) by exposure of procoagulant phosphatidylserine; or iii) by high fibrinogen binding. Yet, their functional role has remained unclear. Here we used a novel transglutaminase probe, Rhod-A14, to identify a subpopulation of platelets with a cross-linked protein coat, and compared this with other platelet subpopulations using a panel of functional assays. Platelet stimulation with convulxin/thrombin resulted in initial integrin αIIbβ3 activation, the appearance of a platelet population with high fibrinogen binding, (independently of active integrins, but dependent on the presence of thrombin) followed by phosphatidylserine exposure and binding of coagulation factors Va and Xa. A subpopulation of phosphatidylserine-exposing platelets bound Rhod-A14 both in suspension and in thrombi generated on a collagen surface. In suspension, high fibrinogen and Rhod-A14 binding were antagonized by combined inhibition of transglutaminase activity and integrin αIIbβ3. Markedly, in thrombi from mice deficient in transglutaminase factor XIII, platelet-driven fibrin formation and Rhod-A14 binding were abolished by blockage of integrin αIIbβ3. Vice versa, star-like fibrin formation from platelets of a patient with deficiency in αIIbβ3 (Glanzmann thrombasthenia) was abolished upon blockage of transglutaminase activity. We conclude that coated platelets, with initial αIIbβ3 activation and high fibrinogen binding, form a subpopulation of phosphatidylserine-exposing platelets, and function in platelet-dependent star-like fibrin fiber formation via transglutaminase factor XIII and integrin αIIbβ3. PMID:26721892

  12. Effect of photodynamic therapy on mouse platelets

    NASA Astrophysics Data System (ADS)

    Zhou, Chuannong; Chi, Shunji; Deng, Jinsheng; Zhang, Hua; Liang, Junlin; Ha, Xian-wen

    1993-03-01

    Normal mice received hematoporphyrin derivative (10 mg/kg iv) immediately, 24 or 48 hrs prior to red light irradiation. The blood was collected and the platelet-rich plasma was irradiated by red light (100 J/cm2). The platelets were fixed immediately, 8 or 16 hrs after irradiation, and processed for EM examination. In comparison with those of control mice, the platelets of all experimental mice showed structural changes: 16 hrs after irradiation all platelets were necrotized; 8 hrs after irradiation almost one fourth of the platelets were necrotized and the remaining were considerably damaged; immediately after irradiation a small number of platelets became necrotic and most other platelets were swollen and deformed, often with many cytoplasmic projections and considerable dilatation of the canalicular membrane system. Our findings provided a clear evidence that platelets are highly sensitive to PDT action and can be directly and rapidly injured by PDT even in the absence of vascular endothelial cells. Our results give firm support to the hypothesis that both endothelial cells and platelets may play an important role in the initiation of early vascular damage and microcirculatory alterations induced by PDT in vivo.

  13. The platelet count in EDTA-anticoagulated blood from patients with thrombocytopenia may be underestimated when measured in routine laboratories.

    PubMed

    Podda, Gian Marco; Pugliano, Mariateresa; Femia, Eti Alessandra; Mezzasoma, Anna Maria; Gresele, Paolo; Carpani, Giovanni; Cattaneo, Marco

    2012-07-01

    Spuriously low platelet counts (PCs) can be observed in normal blood samples anticoagulated with ethylenediamine tetra-acetic acid (EDTA)and, much less frequently, with citrate-tris-pyridossalphosphate (CPT),due to time-dependent in vitro platelet agglutination. Accuracy in PC determination is essential as PC is one of the parameters that usually guides treatment for thrombocytopenic patients. PCs of 93 thrombocy to penic patients were measured in EDTA- or CPT-anticoagulated blood samples immediately after sampling (t0) and 90 min (t90) after storage at room temperature. The presence of platelet agglutinates in blood samples was determined by examining blood smears using optical microscopy.PCs decreased at t90 with both anticoagulants. Platelet agglutinates were present at t90 in 27% of EDTA-samples vs. 2% of CPT-samples with decreased PCs (P < 0.001). Based on PCs in EDTA-samples, 15 patients (16%) shifted from a lower bleeding risk at t0 to a higher bleeding risk category at t90 (P 5 0.019), compared to 5 (5%) patients, based on PCs in CPT-samples. Therefore, time-dependent in vitro platelet agglutination in EDTA-blood samples may cause underestimation of PCs in thrombocytopenic patients, possibly leading to improper management.

  14. The Slc35d3 gene, encoding an orphan nucleotide sugar transporter, regulates platelet-dense granules

    PubMed Central

    Chintala, Sreenivasulu; Tan, Jian; Gautam, Rashi; Rusiniak, Michael E.; Guo, Xiaoli; Li, Wei; Gahl, William A.; Huizing, Marjan; Spritz, Richard A.; Hutton, Saunie; Novak, Edward K.; Swank, Richard T.

    2007-01-01

    Platelet dense granules are lysosome-related organelles which contain high concentrations of several biologically important low-molecular-weight molecules. These include calcium, serotonin, adenine nucleotides, pyrophosphate, and polyphosphate, which are necessary for normal blood hemostasis. The synthesis of dense granules and other lysosome-related organelles is defective in inherited diseases such as Hermansky-Pudlak syndrome (HPS) and Chediak-Higashi syndrome (CHS). HPS and CHS mutations in 8 human and at least 16 murine genes have been identified. Previous studies produced contradictory findings for the function of the murine ashen (Rab27a) gene in platelet-dense granules. We have used a positional cloning approach with one line of ashen mutants to establish that a new mutation in a second gene, Slc35d3, on mouse chromosome 10 is the basis of this discrepancy. The platelet-dense granule defect is rescued in BAC transgenic mice containing the normal Slc35d3 gene. Thus, Slc35d3, an orphan member of a nucleotide sugar transporter family, specifically regulates the contents of platelet-dense granules. Unlike HPS or CHS genes, it has no apparent effect on other lysosome-related organelles such as melanosomes or lysosomes. The ash-Roswell mouse mutant is an appropriate model for human congenital-isolated delta-storage pool deficiency. PMID:17062724

  15. von Willebrand factor (VWF) propeptide binding to VWF D'D3 domain attenuates platelet activation and adhesion.

    PubMed

    Madabhushi, Sri R; Shang, Chengwei; Dayananda, Kannayakanahalli M; Rittenhouse-Olson, Kate; Murphy, Mary; Ryan, Thomas E; Montgomery, Robert R; Neelamegham, Sriram

    2012-05-17

    Noncovalent association between the von Willebrand factor (VWF) propeptide (VWFpp) and mature VWF aids N-terminal multimerization and protein compartmentalization in storage granules. This association is currently thought to dissipate after secretion into blood. In the present study, we examined this proposition by quantifying the affinity and kinetics of VWFpp binding to mature VWF using surface plasmon resonance and by developing novel anti-VWF D'D3 mAbs. Our results show that the only binding site for VWFpp in mature VWF is in its D'D3 domain. At pH 6.2 and 10mM Ca(2+), conditions mimicking intracellular compartments, VWFpp-VWF binding occurs with high affinity (K(D) = 0.2nM, k(off) = 8 × 10(-5) s(-1)). Significant, albeit weaker, binding (K(D) = 25nM, k(off) = 4 × 10(-3) s(-1)) occurs under physiologic conditions of pH 7.4 and 2.5mM Ca(2+). This interaction was also observed in human plasma (K(D) = 50nM). The addition of recombinant VWFpp in both flow-chamber-based platelet adhesion assays and viscometer-based shear-induced platelet aggregation and activation studies reduced platelet adhesion and activation partially. Anti-D'D3 mAb DD3.1, which blocks VWFpp binding to VWF-D'D3, also abrogated platelet adhesion, as shown by shear-induced platelet aggregation and activation studies. Our data demonstrate that VWFpp binding to mature VWF occurs in the circulation, which can regulate the hemostatic potential of VWF by reducing VWF binding to platelet GpIbα.

  16. 21 CFR 864.6650 - Platelet adhesion test.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Platelet adhesion test. 864.6650 Section 864.6650...) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6650 Platelet adhesion test. (a) Identification. A platelet adhesion test is a device used to determine in vitro platelet...

  17. 21 CFR 864.6650 - Platelet adhesion test.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Platelet adhesion test. 864.6650 Section 864.6650...) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6650 Platelet adhesion test. (a) Identification. A platelet adhesion test is a device used to determine in vitro platelet...

  18. Necrotic platelets provide a procoagulant surface during thrombosis

    PubMed Central

    Hua, Vu Minh; Abeynaike, Latasha; Glaros, Elias; Campbell, Heather; Pasalic, Leonardo; Chen, Vivien M. Y.

    2015-01-01

    A subpopulation of platelets fulfills a procoagulant role in hemostasis and thrombosis by enabling the thrombin burst required for fibrin formation and clot stability at the site of vascular injury. Excess procoagulant activity is linked with pathological thrombosis. The identity of the procoagulant platelet has been elusive. The cell death marker 4-[N-(S-glutathionylacetyl)amino]phenylarsonous acid (GSAO) rapidly enters a subpopulation of agonist-stimulated platelets via an organic anion-transporting polypeptide and is retained in the cytosol through covalent reaction with protein dithiols. Labeling with GSAO, together with exposure of P-selectin, distinguishes necrotic from apoptotic platelets and correlates with procoagulant potential. GSAO+ platelets form in occluding murine thrombi after ferric chloride injury and are attenuated with megakaryocyte-directed deletion of the cyclophilin D gene. These platelets form a procoagulant surface, supporting fibrin formation, and reduction in GSAO+ platelets is associated with reduction in platelet thrombus size and fibrin formation. Analysis of platelets from human subjects receiving aspirin therapy indicates that these procoagulant platelets form despite aspirin therapy, but are attenuated by inhibition of the necrosis pathway. These findings indicate that the major subpopulation of platelets involved in fibrin formation are formed via regulated necrosis involving cyclophilin D, and that they may be targeted independent of platelet activation. PMID:26474813

  19. Exogenous modification of platelet membranes with the omega-3 fatty acids EPA and DHA reduces platelet procoagulant activity and thrombus formation.

    PubMed

    Larson, Mark K; Tormoen, Garth W; Weaver, Lucinda J; Luepke, Kristen J; Patel, Ishan A; Hjelmen, Carl E; Ensz, Nicole M; McComas, Leah S; McCarty, Owen J T

    2013-02-01

    Several studies have implicated the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in inhibition of normal platelet function, suggesting a role for platelets in EPA- and DHA-mediated cardioprotection. However, it is unclear whether the cardioprotective mechanisms arise from alterations to platelet-platelet, platelet-matrix, or platelet-coagulation factor interactions. Our previous results led us to hypothesize that EPA and DHA alter the ability of platelets to catalyze the generation of thrombin. We tested this hypothesis by exogenously modifying platelet membranes with EPA and DHA, which resulted in compositional changes analogous to increased dietary EPA and DHA intake. Platelets treated with EPA and DHA showed reductions in the rate of thrombin generation and exposure of platelet phosphatidylserine. In addition, treatment of platelets with EPA and DHA decreased thrombus formation and altered the processing of thrombin precursor proteins. Furthermore, treatment of whole blood with EPA and DHA resulted in increased occlusion time and a sharply reduced accumulation of fibrin under flow conditions. These results demonstrate that EPA and DHA inhibit, but do not eliminate, the ability of platelets to catalyze thrombin generation in vitro. The ability of EPA and DHA to reduce the procoagulant function of platelets provides a possible mechanism behind the cardioprotective phenotype in individuals consuming high levels of EPA and DHA.

  20. Stochastic response of human blood platelets to stimulation of shape changes and secretion.

    PubMed Central

    Deranleau, D A; Lüthy, R; Lüscher, E F

    1986-01-01

    Stopped-flow turbidimetric data indicate that platelets stimulated with low levels of thrombin undergo a shape transformation from disc to "sphere" to smaller spiny sphere that is indistinguishable from the shape change induced by ADP through different membrane receptor sites and a dissimilar receptor trigger mechanism. Under conditions where neither secretion nor aggregation occur, the extinction coefficients for total scattering by each of the three platelet forms are independent of the stimulus applied, and both reaction mechanisms can be described as stochastic (Poisson) processes in which the rate constant for the formation of the transient species is equal to the rate constant for its disappearance. This observation is independent of the shape assignment, and as the concentration of thrombin is increased and various storage organelles secrete increasing amounts of their contents into the external medium, the stochastic pattern persists. Progressively larger decreases in the extinction coefficients of the intermediate and final platelet forms, over and above those that reflect shape alterations alone, accompany or parallel the reaction induced by the higher thrombin concentrations. The excess turbidity decrease observed when full secretion occurs can be wholly accounted for by a decrease in platelet volume equal in magnitude to the fraction of the total platelet volume occupied by alpha granules. Platelet activation, as reported by the whole body light scattering of either shape changes alone or shape changes plus parallel (but not necessarily also stochastic) alpha granule secretion, thus manifests itself as a random series of transient events conceivably with its origins in the superposition of a set of more elementary stochastic processes that could include microtubule depolymerization, actin polymerization, and possibly diffusion. Although the real nature of the control mechanism remains obscure, certain properties of pooled stochastic processes suggest

  1. Platelet morphology and plasma indices of platelet activation in essential hypertension: effects of amlodipine-based antihypertensive therapy.

    PubMed

    Nadar, Sunil; Blann, Andrew D; Lip, Gregory Y H

    2004-01-01

    Platelet abnormalities have been described in hypertension, especially in the presence of target organ damage. Our aim was to study the differences in morphology and indices of platelet activation in treatment-naive patients with essential hypertension as compared to normotensive controls and secondly, to study the effects of amlodipine-based antihypertensive therapy on these indices. We recruited 42 previously untreated, newly diagnosed hypertensive patients (25 men; mean age 53 years) for the cross-sectional study, where data were compared with those from 30 normotensive controls (20 men; mean age 57 years). Of the 42 untreated hypertensive patients who were recruited, 27 patients successfully completed, the six-month treatment phase with amlodipine-based antihypertensive therapy. Platelet morphology (volume and mass) was quantified, and plasma markers of platelet activation (betaTG and sPsel) measured in citrated plasma. The mass of P-selectin in each platelet (pPsel) was determined by lysing a fixed number of platelets and then determining the levels of P-selectin in the lysate. Hypertensive patients had significantly higher platelet volume (P = 0.01) and mass (P = 0.003), plasma betaTG and sPsel, and pPsel levels (all P < 0.001) compared to the controls. After a mean treatment time of 6 months, there was a decrease in platelet volume (P < 0.001) and mass (P = 0.02), with lower pPsel, sPsel and BTG levels (all P < 0.001) compared to the untreated state. Treatment of uncomplicated essential hypertension using amlodipine-based anti-hypertensive therapy results in a reversal of the platelet morphology abnormalities and indices of platelet activation. This may contribute to a reduction in thrombosis-related complications seen in those whose blood pressure lowering is effective.

  2. A Novel Variant in the Platelet Endothelial Aggregation Receptor-1 Gene is Associated with Increased Platelet Aggregabili

    PubMed Central

    Herrera-Galeano, J. Enrique; Becker, Diane M.; Wilson, Alexander F.; Yanek, Lisa R.; Bray, Paul; Vaidya, Dhananjay; Faraday, Nauder; Becker, Lewis C

    2009-01-01

    Objective: Platelet endothelial aggregation receptor-1 (PEAR1) is a recently identified platelet transmembrane protein that becomes activated by platelet contact. We looked for novel genetic variants in PEAR1 and studied their association with agonist-induced native platelet aggregation and with aspirin's inhibitory effect on platelets. Methods and Results: We genotyped PEAR1 for 10 single nucleotide polymorphisms (SNPs), selected for optimal gene coverage at a density of 4kb, in 1486 apparently healthy individuals from two generations of families with premature CAD. Subjects had a mean age of 45 years; 62% were white and 38% African American. Platelet aggregation to collagen, epinephrine, and ADP was measured in platelet rich plasma, at baseline and after 2 weeks of aspirin (ASA, 81 mg/day), and genotype-phenotype associations were examined separately by ethnicity using multivariable generalized linear models adjusted for covariates. The C allele of SNP rs2768759 [A/C], located in the promoter region of the gene, was common in whites and uncommon in African Americans (allele frequency 70.2% vs 17.7%). The C allele was generally associated in both ethnic groups with increased aggregation of native platelets to each agonist. Following ASA, the associations were stronger and more consistent, and remained significant when post ASA aggregation was adjusted for baseline aggregation, consistent with a relationship between the C allele and reduced platelet responsiveness to ASA. The PEAR1 SNP explained up to 6.9% of the locus specific genetic variance in African Americans and up to 2.5% of the genetic variance in whites following ASA. Conclusion: PEAR1 appears to play an important role in agonist-induced platelet aggregation and in the response to ASA in both whites and African Americans. PMID:18511696

  3. Platelet concentration in platelet-rich plasma affects tenocyte behavior in vitro.

    PubMed

    Giusti, Ilaria; D'Ascenzo, Sandra; Mancò, Annalisa; Di Stefano, Gabriella; Di Francesco, Marianna; Rughetti, Anna; Dal Mas, Antonella; Properzi, Gianfranco; Calvisi, Vittorio; Dolo, Vincenza

    2014-01-01

    Since tendon injuries and tendinopathy are a growing problem, sometimes requiring surgery, new strategies that improve conservative therapies are needed. Platelet-rich plasma (PRP) seems to be a good candidate by virtue of its high content of growth factors, most of which are involved in tendon healing. This study aimed to evaluate if different concentrations of platelets in PRP have different effects on the biological features of normal human tenocytes that are usually required during tendon healing. The different platelet concentrations tested (up to 5 × 10(6) plt/µL) stimulated differently tenocytes behavior; intermediate concentrations (0.5 × 10(6), 1 × 10(6) plt/µL) strongly induced all tested processes (proliferation, migration, collagen, and MMPs production) if compared to untreated cells; on the contrary, the highest concentration had inhibitory effects on proliferation and strongly reduced migration abilities and overall collagen production but, at the same time, induced increasing MMP production, which could be counterproductive because excessive proteolysis could impair tendon mechanical stability. Thus, these in vitro data strongly suggest the need for a compromise between extremely high and low platelet concentrations to obtain an optimal global effect when inducing in vivo tendon healing.

  4. Platelet Concentration in Platelet-Rich Plasma Affects Tenocyte Behavior In Vitro

    PubMed Central

    Rughetti, Anna; Dal Mas, Antonella; Properzi, Gianfranco; Calvisi, Vittorio

    2014-01-01

    Since tendon injuries and tendinopathy are a growing problem, sometimes requiring surgery, new strategies that improve conservative therapies are needed. Platelet-rich plasma (PRP) seems to be a good candidate by virtue of its high content of growth factors, most of which are involved in tendon healing. This study aimed to evaluate if different concentrations of platelets in PRP have different effects on the biological features of normal human tenocytes that are usually required during tendon healing. The different platelet concentrations tested (up to 5 × 106 plt/µL) stimulated differently tenocytes behavior; intermediate concentrations (0.5 × 106, 1 × 106 plt/µL) strongly induced all tested processes (proliferation, migration, collagen, and MMPs production) if compared to untreated cells; on the contrary, the highest concentration had inhibitory effects on proliferation and strongly reduced migration abilities and overall collagen production but, at the same time, induced increasing MMP production, which could be counterproductive because excessive proteolysis could impair tendon mechanical stability. Thus, these in vitro data strongly suggest the need for a compromise between extremely high and low platelet concentrations to obtain an optimal global effect when inducing in vivo tendon healing. PMID:25147809

  5. Identification of functional VEGF receptors on human platelets.

    PubMed

    Selheim, Frode; Holmsen, Holm; Vassbotn, Flemming S

    2002-02-13

    Platelets secrete platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF) upon stimulation. We have demonstrated that platelets have functionally active PDGF alpha-receptors, a transmembrane tyrosine kinase involved in negative feedback regulation. Here we demonstrate the presence of the related VEGF receptors fms-like tyrosine kinase-1 and kinase-insert domain region on human platelets. VEGF itself did not cause platelet aggregation. However, addition of exogenous VEGF to SFRLLN or thrombin-stimulated platelets potentiated platelet aggregation. Moreover, thrombin-induced phosphoinositide 3-kinase and mitogen-activated protein kinase activity were enhanced in the presence of VEGF.

  6. High-frequency (13.56-MHz) and ultrahigh-frequency (915-MHz) radio identification systems do not affect platelet activation and functions.

    PubMed

    Rogowska, Anna; Chabowska, Anna Małgorzata; Lipska, Alina; Boczkowska-Radziwon, Barbara; Bujno, Magdalena; Rusak, Tomasz; Dziemianczuk, Mateusz; Radziwon, Piotr

    2016-05-01

    In radiofrequency identification (RFID) systems used in labeling of blood components, blood cells are subjected to the direct influence of electromagnetic waves throughout the storage period. The aim of this study was to prove the safety of storage of platelet concentrates (PCs) in containers labeled with RFID tags. Ten pooled PCs obtained from 12 buffy coats each suspended in additive solution were divided into three separate containers that were assigned to three groups: control, PCs labeled with ultrahigh frequency (UHF) range tags and exposed to 915-MHz radio waves, and PCs labeled with high-frequency (HF) range tags and exposed to 13.56-MHz radio waves. PCs were stored at 20 to 24°C for 7 days. In vitro tests of platelet (PLT) function were performed on the first, fifth, and seventh days of storage. There were no significant differences in pH; hypotonic shock resistance; surface expression of CD62P, CD42a, or CD63; release of PLT-derived microparticles; PLT aggregation; and number of PLTs between PCs stored at a constant exposure to radio waves of two different frequencies and the control group on the first, fifth, and seventh days of storage. The results of the study indicate no impact of electromagnetic radiation generated in HF and UHF RFID systems and constant contact with the tags on the quality of stored PCs. © 2016 AABB.

  7. Preclinical Investigation of Lyophilized Platelet Preparations

    DTIC Science & Technology

    1994-10-31

    Western blots of rehydrated platelet preparations. The AMAC antibody reacted strongly with a high molecular weight protein in the fresh platelet lysate , and...to a lesser degree with a protein of identical molecular weight in the rehydrated platelet lysate . The antibody to fibrinogen reacted strongly with

  8. Effects of protopine on blood platelet aggregation. II. Effect on metabolic system of adenosine 3',5'-cyclic monophosphate in platelets.

    PubMed

    Shiomoto, H; Matsuda, H; Kubo, M

    1990-08-01

    The mode of action of protopine on rabbit platelet aggregation was investigated in the metabolic system of adenosine 3',5'-cyclic monophosphate (cyclic AMP) in vitro experimental models. The inhibitory activity of protopine on adenosine 5'-diphosphate induced platelet aggregation was increased in the presence of prostaglandin I2 or papaverine in platelets. Protopine elevated content of the basal cyclic AMP accumulation in platelets and enhanced activity of crude adenylate cyclase prepared from platelets, but was ineffective on cyclic AMP phosphodiesterase. It is concluded that protopine has an inhibitory activity on platelet aggregation, activates adenylate cyclase and increases cyclic AMP content in platelets, in addition to other inhibitory actions in the metabolic system of cyclic AMP.

  9. Human plasma platelet-derived exosomes: effects of aspirin.

    PubMed

    Goetzl, Edward J; Goetzl, Laura; Karliner, Joel S; Tang, Norina; Pulliam, Lynn

    2016-05-01

    Platelet-derived exosomes mediate platelet atherogenic interactions with endothelial cells and monocytes. A new method for isolation of plasma platelet-derived exosomes is described and used to examine effects of aging and aspirin on exosome cargo proteins. Exosome secretion by purified platelets in vitro did not increase after exposure to thrombin or collagen, as assessed by exosome counts and quantification of the CD81 exosome marker. Thrombin and collagen increased exosome content of α-granule chemokines CXCL4 and CXCL7 and cytoplasmic high-mobility group box 1 (HMGB1) protein, but not membrane platelet glycoprotein VI (GPVI), with dependence on extracellular calcium. Aspirin consumption significantly blocked thrombin- and collagen-induced increases in exosome cargo levels of chemokines and HMGB1, without altering total exosome secretion or GPVI cargo. Plasma platelet-derived exosomes, enriched by absorption with mouse antihuman CD42b [platelet glycoprotein Ib (GPIb)] mAb, had sizes and cargo protein contents similar to those of exosomes from purified platelets. The plasma platelet-derived exosome number is lower and its chemokine and HMGB1 levels higher after age 65 yr. Aspirin consumption significantly suppressed cargo protein levels of plasma platelet-derived exosomes without altering total levels of exosomes. Cargo proteins of human plasma platelet-derived exosomes may biomark platelet abnormalities and in vivo effects of drugs.- Goetzl, E. J., Goetzl, L., Karliner, J. S., Tang, N., Pulliam, L. Human plasma platelet-derived exosomes: effects of aspirin. © FASEB.

  10. Depressed reticuloendothelial clearance of platelets in rats after trauma.

    PubMed

    Kaplan, J E; Moon, D G; Minnear, F L; Saba, T M

    1984-02-01

    Platelet microembolization may contribute to microcirculatory and organ damage following trauma and shock. It is hypothesized that posttraumatic reticuloendothelial depression predisposes to such microembolization by failure to clear altered platelets from the circulation. The present study evaluated the short-term (1 h) clearance and organ localization of radiolabeled homologous damaged platelets in normal rats and in rats following sublethal Noble-Collip drum trauma. Platelets were collected in citrated platelet-rich plasma from normal rats and labeled with 51Cr in citrated saline. Platelets were altered by repeated centrifugation in protein-free medium. These platelets differed functionally and morphologically from normal platelets. Disappearance of iv injected damaged platelets conformed to a two-compartment exponential clearance. Velocity of clearance in the rapid compartment correlated with hepatic platelet localization, whereas velocity of clearance in the second compartment correlated with splenic platelet localization. Clearance rate of the rapid compartment was depressed at 1 h after trauma and elevated at 24 h. These changes were associated with a decrease in hepatic platelet localization at 1 h and an increase above normal at 24 h. Splenic platelet localization was decreased by 3 h following trauma. Pulmonary platelet localization was increased at all times following trauma. It is concluded that the posttrauma state is associated with a defect in the reticuloendothelial system clearance of altered platelets, which may augment embolization of platelets in the lung.

  11. Dabigatran and rivaroxaban do not affect AA- and ADP-induced platelet aggregation in patients receiving concomitant platelet inhibitors.

    PubMed

    Olivier, Christoph B; Weik, Patrick; Meyer, Melanie; Weber, Susanne; Diehl, Philipp; Bode, Christoph; Moser, Martin; Zhou, Qian

    2016-08-01

    Dabigatran and rivaroxaban are novel, vitamin K-independent oral anticoagulants (NOACs) and act via antagonism of the coagulation factor (F) IIa (dabigatran) or FXa (rivaroxaban), respectively. Compared to vitamin-K-antagonists, NOACs have shown non-inferiority of risk and benefit in patients with non valvular atrial fibrillation (AF). In clinical practice there is increasing use of NOACs combined with platelet inhibitors in patients with AF and coronary artery disease. However, whether NOACs affect the function of platelet inhibitors remains incompletely known. This observational study aimed to assess the platelet function in patients receiving dabigatran or rivaroxaban and concomitant platelet inhibitors. A single centre observational study was performed analysing the platelet aggregation of patients treated with dabigatran or rivaroxaban with or without concomitant platelet inhibitors. Measurements before the initiation of NOAC therapy served as the respective control group. Platelet aggregation was measured by multiple electrode aggregometry and was induced with adenosine diphosphate (ADP, 6.5 µM) and arachidonic acid (AA, 0.5 mM), respectively. In order to evaluate whether NOACs interact with platelet inhibition by ASA or the P2Y12-antagonist clopidogrel, 87 patients were grouped according to their concomitant antiplatelet medication. Comparing the ADP- and AA-induced platelet aggregation in patients without concomitant platelet inhibitors (n = 45) no significant differences under therapy with dabigatran (d) or rivaroxaban (r) compared to the control group (c) were observed. In patients taking clopidogrel as a concomitant platelet inhibitor (n = 21), neither dabigatran nor rivaroxaban affected the ADP-induced platelet aggregation (c 20 ± 11, d 21 ± 14, r 18 ± 8 AU*min, p = 0.200). Patients receiving dabigatran or rivaroxaban in combination with ASA (n = 42; 21 ASA only, 21 ASA + clopidogrel) showed no significant differences of the AA

  12. Heterogeneity of antibody response to human platelet transfusion.

    PubMed Central

    Wu, K K; Thompson, J S; Koepke, J A; Hoak, J C; Flink, R

    1976-01-01

    To study the antibody response to human platelet transfusions, nine thrombocytopenia patients with bone marrow failure were given 6 U (3X10(11)) of random platelet concentrates twice a week. Before transfusion, none of the patients had preexisting antibodies detectable with lymphocytotoxicity, platelet aggregation, or capillary leukoagglutination techniques. After receiving 18-78 U of platelets, they became refractory to further transfusions of random platelets and alloantibodies were detectable. Two patterns of antibody response could be identified. In three patients, the sera were not lymphocytotoxic with a panel of standard cells in which all the known HLA antigens in the first and second series were represented at least once. Yet, they caused platelet aggregation with 30, 24, and 60%, respectively, of a donor population studied. The aggregating activities were inhibited by antihuman IgG but not by antihuman IgA or antihuman IgM antiserum. The aggregating antibodies could be absorbed out with donor platelets but not lymphocytes or granulocytes. Antibodies from two of these patients aggregated platelets of their respective siblings matched for both HLA haplotypes. Transfusion of platelets from these two siblings did not increase the platelet count while platelets obtained from aggregation-negative donors did. The sera from the remaining six patients were lymphocytotoxic with 15-100% of the panel of standard cells. They also had aggregating antibodies, which could be absorbed out by both platelets and lymphocytes, suggesting that they were HLA antibodies. These data suggest that the development of platelet-specific antibodies may play an important role in the immunological rejection of isologous platelets, and should be considered in the selection of donors for patients who are refractory to platelets from random donors. PMID:956376

  13. Platelet activation by Histophilus somni and its lipooligosaccharide induces endothelial cell proinflammatory responses and platelet internalization.

    PubMed

    Kuckleburg, Christopher J; McClenahan, Dave J; Czuprynski, Charles J

    2008-02-01

    Histophilus somni is a gram-negative coccobacillus that causes respiratory and reproductive disease in cattle. The hallmark of systemic H. somni infection is diffuse vascular inflammation that can lead to an acute central nervous system disease known as thrombotic meningoencephalitis. Previously, we demonstrated that H. somni and its lipooligosaccharide (LOS) activate bovine platelets, leading to expression of P selectin, CD40L, and FasL. Because activated platelets have been reported to induce endothelial cell cytokine production and adhesion molecule expression, we sought to determine if bovine platelets induce proinflammatory and procoagulative changes in bovine pulmonary artery endothelial cells. Endothelial cells were incubated with platelets activated with adenosine diphosphate, H. somni, or H. somni LOS. Incubation with activated bovine platelets significantly increased expression of in adhesion molecules (intercellular adhesion molecule 1, E selectin) and tissue factor, as measured by flow cytometry, real-time polymerase chain reaction, and Western blot analysis. Activated platelets also up-regulated expression of endothelial cell IL-1beta, monocyte chemoattractant protein 1, and macrophage inflammatory protein 1alpha as determined by real-time polymerase chain reaction and an IL-1beta enzyme-linked immunosorbent assay. An interesting and surprising finding was that bovine platelets activated by H. somni or its LOS were internalized by bovine endothelial cells as visualized by transmission electron microscopy. This internalization seemed to correlate with endothelial cell activation and morphological changes indicative of cell stress. These findings suggest that activated platelets might play a role in promoting vascular inflammation during H. somni infection.

  14. Pathogen reduction by ultraviolet C light effectively inactivates human white blood cells in platelet products.

    PubMed

    Pohler, Petra; Müller, Meike; Winkler, Carla; Schaudien, Dirk; Sewald, Katherina; Müller, Thomas H; Seltsam, Axel

    2015-02-01

    Residual white blood cells (WBCs) in cellular blood components induce a variety of adverse immune events, including nonhemolytic febrile transfusion reactions, alloimmunization to HLA antigens, and transfusion-associated graft-versus-host disease (TA-GVHD). Pathogen reduction (PR) methods such as the ultraviolet C (UVC) light-based THERAFLEX UV-Platelets system were developed to reduce the risk of transfusion-transmitted infection. As UVC light targets nucleic acids, it interferes with the replication of both pathogens and WBCs. This preclinical study aimed to evaluate the ability of UVC light to inactivate contaminating WBCs in platelet concentrates (PCs). The in vitro and in vivo function of WBCs from UVC-treated PCs was compared to that of WBCs from gamma-irradiated and untreated PCs by measuring cell viability, proliferation, cytokine secretion, antigen presentation in vitro, and xenogeneic GVHD responses in a humanized mouse model. UVC light was at least as effective as gamma irradiation in preventing GVHD in the mouse model. It was more effective in suppressing T-cell proliferation (>5-log reduction in the limiting dilution assay), cytokine secretion, and antigen presentation than gamma irradiation. The THERAFLEX UV-Platelets (MacoPharma) PR system can substitute gamma irradiation for TA-GVHD prophylaxis in platelet (PLT) transfusion. Moreover, UVC treatment achieves suppression of antigen presentation and inhibition of cytokine accumulation during storage of PCs, which has potential benefits for transfusion recipients. © 2014 AABB.

  15. Platelet lysate mucohadesive formulation to treat oral mucositis in graft versus host disease patients: a new therapeutic approach.

    PubMed

    Del Fante, Claudia; Perotti, Cesare; Bonferoni, Maria Cristina; Rossi, Silvia; Sandri, Giuseppina; Ferrari, Franca; Scudeller, Luigia; Caramella, Carla Marcella

    2011-09-01

    Optimal treatment of oral mucositis (OM) due to graft versus host disease (GvHD) is currently not available. Platelet-derived growth factors (PDGFs) have high capability for tissue healing and may play a role in repairing the mucosal barrier. The aim of the present work was to develop a mucoadhesive formulation to administer platelet lysate to oral cavity prolonging contact time of platelet lysate with oral mucosa. The mucoadhesive formulation was characterized for in vitro properties (PDGF-AB concentration, mucoadhesive properties, cytotoxicity, fibroblast proliferation, wound healing). Moreover, a preliminary clinical study on seven GvHD patients with OM refractory to other therapies was conducted, to evaluate feasibility, safety, and efficacy. GVPL (mucoadhesive gel vehicle mixed with platelet lysate)showed good mucoadhesive properties; additionally, it was characterized by good biocompatibility in vitro on fibroblasts and it was able to enhance fibroblast proliferation and wound healing, maintaining the efficacy for up to 14 days following storage at 2-8°C. In vivo, clinical response was good-to-complete in five, fair in one, none in the remaining one. The in vitro results indicate that GVPL has optimal mucoadhesive and healing enhancer properties, maintained over time (up to 14 days); preliminary clinical results suggest that oral application of platelet lysate-loaded mucoadhesive formulation is feasible, safe, well tolerated, and effective. A larger controlled randomized study is needed.

  16. Evaluation of four methods for platelet compatibility testing

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    McFarland, J.G.; Aster, R.H.

    1987-05-01

    Four platelet compatibility assays were performed on serum and platelet or lymphocyte samples from 38 closely HLA-matched donor/recipient pairs involved in 55 single-donor platelet transfusions. The 22 patients studied were refractory to transfusions of pooled random-donor platelets. Of the four assays (platelet suspension immunofluorescence, PSIFT; /sup 51/Cr release; microlymphocytotoxicity; and a monoclonal anti-IgG assay, MAIA), the MAIA was most predictive of platelet transfusion outcome (predictability, 74% for one-hour posttransfusion platelet recovery and 76% for 24-hour recovery). The only other assay to reach statistical significance was the PSIFT (63% predictability for one-hour posttransfusion recovery). The degree of HLA compatibility between donormore » and recipient (exact matches v those utilizing cross-reactive associations) was unrelated to the ability of the MAIA to predict transfusion results. The MAIA may be capable of differentiating HLA antibodies, ABO antibodies, and platelet-specific antibodies responsible for failure of HLA-matched and selectively mismatched single-donor platelet transfusions.« less

  17. The effect of molar pregnancies on platelet parameters.

    PubMed

    Soylu Karapınar, Oya; Benk Şilfeler, Dilek; Dolapçıoğlu, Kenan; Keskin Kurt, Raziye; Beyazıt, Ahmet

    2016-10-01

    The aim of this study was to compare platelet parameters between abortus groups with gestational trophoblastic disease (GTD) (molar pregnancy, invasive mole, choriocarcinoma, etc) and without disease according to pathological result. The study population consisted of patients with GTD (n = 53) and aborted patients without disease as a control group (n = 53) who were seen in our clinic between January 2010 and December 2013. In this retrospective study, age, gravidity, levels of haemoglobin, white blood cell count, platelets, platelet parameters (mean platelet volume (MPV), platelet distrubition width (PDW), platelet crit (PCT), which shows platelet functions were recorded. The pathological diagnosis of GTD was recorded. The mean platelet count, MPV, PDW and PCT levels were similar between the groups. There is no statistically significiant difference between types of GTN in these parameters according to pathological diagnosis. According to our study results, platelet count and levels of MPV, PDW ve PCT in GTD patients were similar to aborted patients without disease.

  18. The life cycle of platelet granules.

    PubMed

    Sharda, Anish; Flaumenhaft, Robert

    2018-01-01

    Platelet granules are unique among secretory vesicles in both their content and their life cycle. Platelets contain three major granule types-dense granules, α-granules, and lysosomes-although other granule types have been reported. Dense granules and α-granules are the most well-studied and the most physiologically important. Platelet granules are formed in large, multilobulated cells, termed megakaryocytes, prior to transport into platelets. The biogenesis of dense granules and α-granules involves common but also distinct pathways. Both are formed from the trans -Golgi network and early endosomes and mature in multivesicular bodies, but the formation of dense granules requires trafficking machinery different from that of α-granules. Following formation in the megakaryocyte body, both granule types are transported through and mature in long proplatelet extensions prior to the release of nascent platelets into the bloodstream. Granules remain stored in circulating platelets until platelet activation triggers the exocytosis of their contents. Soluble N -ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins, located on both the granules and target membranes, provide the mechanical energy that enables membrane fusion during both granulogenesis and exocytosis. The function of these core fusion engines is controlled by SNARE regulators, which direct the site, timing, and extent to which these SNAREs interact and consequently the resulting membrane fusion. In this review, we assess new developments in the study of platelet granules, from their generation to their exocytosis.

  19. Glutamate mediates platelet activation through the AMPA receptor

    PubMed Central

    Morrell, Craig N.; Sun, Henry; Ikeda, Masahiro; Beique, Jean-Claude; Swaim, Anne Marie; Mason, Emily; Martin, Tanika V.; Thompson, Laura E.; Gozen, Oguz; Ampagoomian, David; Sprengel, Rolf; Rothstein, Jeffrey; Faraday, Nauder; Huganir, Richard; Lowenstein, Charles J.

    2008-01-01

    Glutamate is an excitatory neurotransmitter that binds to the kainate receptor, the N-methyl-D-aspartate (NMDA) receptor, and the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor (AMPAR). Each receptor was first characterized and cloned in the central nervous system (CNS). Glutamate is also present in the periphery, and glutamate receptors have been identified in nonneuronal tissues, including bone, heart, kidney, pancreas, and platelets. Platelets play a central role in normal thrombosis and hemostasis, as well as contributing greatly to diseases such as stroke and myocardial infarction. Despite the presence of glutamate in platelet granules, the role of glutamate during hemostasis is unknown. We now show that activated platelets release glutamate, that platelets express AMPAR subunits, and that glutamate increases agonist-induced platelet activation. Furthermore, we demonstrate that glutamate binding to the AMPAR increases intracellular sodium concentration and depolarizes platelets, which are important steps in platelet activation. In contrast, platelets treated with the AMPAR antagonist CNQX or platelets derived from GluR1 knockout mice are resistant to AMPA effects. Importantly, mice lacking GluR1 have a prolonged time to thrombosis in vivo. Our data identify glutamate as a regulator of platelet activation, and suggest that the AMPA receptor is a novel antithrombotic target. PMID:18283118

  20. Platelet growth factors from allogeneic platelet-rich plasma for clinical improvement in split-thickness skin graft.

    PubMed

    Sonker, Atul; Dubey, Anju; Bhatnagar, Ankur; Chaudhary, Rajendra

    2015-01-01

    Platelets are a source of numerous growth factors which facilitate repair and healing. Thus platelet rich plasma has been increasingly used as a treatment modality in the field of reconstructive surgeries for wound healing. This preliminary study was carried out to explore whether platelet growth factors from platelet rich plasma could be used for enhancement of split thickness skin graft survival. Twenty patients (13 males and 7 females) requiring split thickness skin graft for various clinical reasons were enrolled in the study. Platelet rich plasma was collected by apheresis and frozen at -80° C. It was thawed at room temperature immediately before its intended application. PRP was applied only on one half of the wound, while another half served as control. Patient was followed for 6 weeks. The effect was assessed at first dressing in terms of graft uptake and subsequently as time taken for complete healing. There was 100% uptake of the graft in the area where platelet rich plasma was applied. In the control area, there was complete graft loss in 4 cases, partial loss in 7 cases and complete uptake in 9 cases. This study demonstrated promising results on application of PRP to split thickness skin grafts. Further randomized studies with greater sample size may be undertaken to establish platelet rich plasma as a validated treatment modality.

  1. Chitosan inhibits platelet-mediated clot retraction, increases platelet-derived growth factor release, and increases residence time and bioactivity of platelet-rich plasma in vivo.

    PubMed

    Deprés-Tremblay, Gabrielle; Chevrier, Anik; Tran-Khanh, Nicolas; Nelea, Monica; Buschmann, Michael D

    2017-11-10

    Platelet-rich plasma (PRP) has been used to treat different orthopedic conditions, however, the clinical benefits of using PRP remain uncertain. Chitosan (CS)-PRP implants have been shown to improve meniscus, rotator cuff and cartilage repair in pre-clinical models. The purpose of this current study was to investigate in vitro and in vivo mechanisms of action of CS-PRP implants. Freeze-dried formulations containing 1% (w/v) CS (80% degree of deacetylation and number average molar mass 38 kDa), 1% (w/v) trehalose as a lyoprotectant and 42.2 mM calcium chloride as a clot activator were solubilized in PRP. Gravimetric measurements and molecular/cellular imaging studies revealed that clot retraction is inhibited in CS-PRP hybrid clots through physical coating of platelets, blood cells and fibrin strands by chitosan, which interferes with platelet aggregation and platelet-mediated clot retraction. Flow cytometry and ELISA assays revealed that platelets are activated and granules secreted in CS-PRP hybrid clots and that cumulative release of platelet-derived growth factor (PDGF-AB) and epidermal growth factor is higher from CS-PRP hybrid clots compared to PRP clots in vitro. Finally, CS-PRP implants resided for up to 6 weeks in a subcutaneous implantation model and induced cell recruitment and granulation tissue synthesis, confirming greater residency and bioactivity compared to PRP in vivo.

  2. Platelet Glycoprotein lb-1X and Malignancy

    DTIC Science & Technology

    2010-09-01

    supporting the accumulation of more platelets and the elaboration of a fibrin - rich network produced by coagulation factors. This paradigm has been...a platelet - rich thrombus by tethering the platelet to a thrombogenic surface. Several ligands binding to GP Ib-IX have been identified, including...08-1-0576 TITLE: Platelet Glycoprotein lb-1X and Malignancy PRINCIPAL INVESTIGATOR: Dr. Jerry Ware

  3. Is platelet function as measured by Thrombelastograph monitoring in whole blood affected by platelet inhibitors?

    PubMed

    Bailey, Lori A; Sistino, Joseph J; Uber, Walter E

    2005-03-01

    Platelet inhibitors, especially the glycoprotein (GP) IIb/IIIa receptor antagonists, have demonstrated their effectiveness in reducing the acute ischemic complications of percutaneous coronary intervention (PCI) and in improving clinical outcomes in patients with acute coronary crisis. Three common platelet inhibitors observed in emergent cardiopulmonary bypass (CPB) for failed PCI are abciximab, eptifibatide, and tirofiban. An in vitro model was constructed in two parts to determine whether platelet aggregation inhibition induced by platelet inhibitors would be demonstrated by the Thrombelastograph (TEG) monitor when compared with baseline samples with no platelet inhibitor. In part A, 20 mL of fresh whole blood was divided into four groups: group I = baseline, group A = abcix-imab microg/mL, group E = eptifibatide ng/mL, and group T = tirofiban ng/mL. Platelet inhibitor concentrations in whole blood were derived starting with reported serum concentrations with escalation to achieve 80% platelet inhibition using the Medtronic hemoSTATUS and/or Lumi-aggregometer. A concentration range determined by our in vitro tests were chosen for each drug using concentrations achieving less than, equal to, or greater than 80% platelet inhibition. In part B, TEG analysis was then performed using baseline and concentrations for each drug derived in part A. Parameters measured were clot formation reaction time (R), coagulation time (K), maximum amplitude (MA) and alpha angle (A). Groups E1000 and E2000 extended R over control by 37% and 23%, respectively (p = 0.01 and 0.03). Groups E1000 and E2000 increased K times by 45% and 58% (p = .02 and .04). T160 samples prolonged K by 20% (p = 0.01). The angle or clot strength (A) was decreased in groups T160 and E1000 by 23% (+ 7.06 SD) and 18% (+ 11.23 SD), respectively (p = 0.001 and 0.01). The MA decrease was statistically significant in the T160, E1000 and E2000 by 9%, 6% and 13% respectively (p = 0.01). Samples treated with abciximab

  4. Nicergoline inhibits human platelet Ca(2+) signalling through triggering a microtubule-dependent reorganization of the platelet ultrastructure.

    PubMed

    Walford, T; Musa, F I; Harper, A G S

    2016-01-01

    Recently, we demonstrated that a pericellular Ca(2+) recycling system potentiates agonist-evoked Ca(2+) signalling and granule secretion in human platelets and hypothesized a role for the membrane complex (MC) in orchestrating the accumulation of Ca(2+) in the pericellular region. Previous work has demonstrated that treatment with high concentrations of nicergoline may disrupt the MC through an ability to trigger a re-organization of the dense tubular system. Experiments were therefore performed to assess whether nicergoline-induced changes in platelet ultrastructure affects thrombin-evoked Ca(2+) fluxes and dense granule secretion. Thrombin-evoked Ca(2+) fluxes were monitored in Fura-2- or Fluo-5N-loaded human platelets, or using platelet suspensions containing Fluo-4 or Rhod-5N K(+) salts. Fluorescence microscopy was utilized to monitor microtubule structure and intracellular Ca(2+) store distribution in TubulinTracker- and Fluo-5N-loaded platelets respectively. Dense granule secretion was monitored using luciferin-luciferase. Nicergoline treatment inhibited thrombin-evoked Ca(2+) signalling and induced alterations in the microtubule structure and the distribution of intracellular Ca(2+) stores in platelets. Nicergoline altered the generation and spreading of thrombin-induced pericellular Ca(2+) signals and almost completely prevented dense granule secretion. Stabilization of microtubules using taxol reversed most effects of nicergoline on platelet Ca(2+) signalling and partially reversed its effects on dense granule secretion. Nicergoline-induced alterations to platelet ultrastructure disrupt platelet Ca(2+) signalling in a manner that would be predicted if the MC had been disrupted. These data suggest that nicergoline may be a useful prototype for the discovery of novel MC-disrupting anti-thrombotics. © 2015 The British Pharmacological Society.

  5. [Effect of protopine on rabbit platelet function].

    PubMed

    Ma, G Y; Zhang, Z Z; Chen, Z H

    1994-07-01

    Protopine (Pro) inhibited dose-dependently rabbit platelet aggregation induced by ADP, arachidonic acid (AA), collagen, or aggregoserpentin of Trimeresurus mucrosquamatus venom (TMVA) in vitro. Their IC50 were 25.3, 30.5, 46.9, 33.4 mumol.L-1, respectively. Pro 10, 20 mg.kg-1 iv also inhibited the platelet aggregation induced by these inducers. The effects (maximal at 5 min) lasted 1 h. By using fluorophotometry and RIA, it was seen that Pro suppressed the release of 5-HT from platelets during aggregation induced by collagen, AA, or TMVM in vitro. Pro did not block the formation of thromboxane A2 during aggregation induced by AA and did not increase the content of cAMP in rabbit platelet, but increased the content of cGMP in rabbit platelets. The antiplatelet effect of Pro may be related to an increase cGMP in rabbit platelets and the suppression of the release of the active substances from platelets.

  6. Characterization of the aggregation responses of camel platelets.

    PubMed

    Al Ghumlas, Abeer K; Gader, Abdel Galil M Abdel

    2013-09-01

    Despite evidence of active hemostasis, camel platelets barely respond to common aggregating agents at standard doses used for human platelet aggregation. The purpose of the study was to find out whether camel platelets can be activated by high doses or combinations of aggregation agonists, and to characterize the receptor that mediates the aggregation response to adenosine diphosphate (ADP), the most potent agonist for camel platelets known so far. Aggregation studies were performed with platelet-rich plasma (PRP) in response to multiple doses or combinations of ADP, epinephrine (EPN), collagen, and arachidonic acid (AA). Aggregation responses to ADP were performed before and after the addition of the ADP receptor (P2Y12) antagonist Clopidogrel. Camel platelets responded to ADP at doses higher than the standard dose for human platelets, and to combinations of EPN and other agonists, while no aggregation was elicited with EPN or AA alone. Clopidogrel blocked the ADP-induced aggregation responses in a dose-dependent fashion in vitro. Camel platelet aggregation can be activated by increasing the dose of some agonists such as ADP, but not AA or EPN. Irreversible aggregation of camel platelets could also be triggered by a combination of EPN and ADP, and collagen and AA. Inhibition with clopidogrel suggests that camel platelets express the ADP receptor, P2Y12. Understanding platelet function in camels will add to the understanding of platelet function in health and disease. © 2013 American Society for Veterinary Clinical Pathology.

  7. Immature platelet fraction in bacterial sepsis severity assessment

    NASA Astrophysics Data System (ADS)

    Djuang, M. H.; Ginting, F.; Hariman, H.

    2018-03-01

    Sepsis is an infection-induced syndrome, mostly caused by bacteria, of organ dysfunctions that caused by host response dysregulations. One of the simplest sepsis-indicator is platelet and its indexes. A new platelet parameter called immature platelet count (IPF) became theinterest in this study. The study aims to see whether IPF could assess sepsis severity by procalcitonin (PCT).Sixty-four of seventy-one patients with increased PCT were included in this cross-sectional study and separated into three groups based on their PCT levels. IPF showed no significance among the three groups (p-value>0.05) while platelet count was significant (p-value<0.05). Mean Platelet Volume (MPV) and Platelet Distribution Width (PDW) showed a strongpositive correlation with IPF. Higher sepsis severity based on PCT showed larger platelet count, as the result of platelet destructions caused by pro-inflammatory cytokines and endotoxins.

  8. An Inherited Platelet Function Defect in Basset Hounds

    PubMed Central

    Johnstone, I. B.; Lotz, F.

    1979-01-01

    An inherited platelet function defect occurring in a family of basset hounds has been described. The trait is transmitted as an autosomal characteristic and appears to be expressed clinically only in the homozygous state. The characteristics of this platelet defect include: 1) marked bleeding tendencies and prolonged skin bleeding times in either male or female dogs. 2) normal blood coagulation mechanism. 3) adequate numbers of circulating platelets which appear morphologically normal by light microscopy. 4) normal whole blood clot retraction. 5) deficient in vivo platelet consumption and in vitro platelet retention in glass bead columns. 6) defective ADP-induced platelet aggregation in homozygotes, apparently normal ADP response in heterozygotes, and defective collagen-induced platelet aggregation in both. PMID:509382

  9. Differential Dynamics of Platelet Contact and Spreading

    PubMed Central

    Lee, Dooyoung; Fong, Karen P.; King, Michael R.; Brass, Lawrence F.; Hammer, Daniel A.

    2012-01-01

    Platelet spreading is critical for hemostatic plug formation and thrombosis. However, the detailed dynamics of platelet spreading as a function of receptor-ligand adhesive interactions has not been thoroughly investigated. Using reflection interference contrast microscopy, we found that both adhesive interactions and PAR4 activation affect the dynamics of platelet membrane contact formation during spreading. The initial growth of close contact area during spreading was controlled by the combination of different immobilized ligands or PAR4 activation on fibrinogen, whereas the growth of the total area of spreading was independent of adhesion type and PAR4 signaling. We found that filopodia extend to their maximal length and then contract over time; and that filopodial protrusion and expansion were affected by PAR4 signaling. Upon PAR4 activation, the integrin αIIbβ3 mediated close contact to fibrinogen substrata and led to the formation of ringlike patterns in the platelet contact zone. A systematic study of platelet spreading of GPVI-, α2-, or β3-deficient platelets on collagen or fibrinogen suggests the integrin α2 is indispensable for spreading on collagen. The platelet collagen receptors GPVI and α2 regulate integrin αIIbβ3-mediated platelet spreading on fibrinogen. This work elucidates quantitatively how receptor-ligand adhesion and biochemical signals synergistically control platelet spreading. PMID:22325269

  10. Effects of Platelet-Poor Plasma, Platelet-Rich Plasma, and Platelet-Rich Fibrin on Healing of Extraction Sockets with Buccal Dehiscence in Dogs

    PubMed Central

    Hatakeyama, Ichiro; Takahashi, Yukinobu; Omura, Ken

    2014-01-01

    Alveolar bone resorption generally occurs during healing after tooth extraction. This study aimed to evaluate the effects of platelet-poor plasma (PPP), platelet-rich plasma (PRP), and platelet-rich fibrin (PRF) on healing in a ridge-augmentation model of the canine socket with dehiscence of the buccal wall. The third mandibular premolars of 12 beagle dogs were extracted and a 3 mm buccal dehiscence from the alveolar crest to the buccal wall of the extraction socket was created. These sockets were then divided into four groups on the basis of the material used to fill the sockets: PPP, PRP, PRF, and control (no graft material) groups. Results were evaluated at 4 and 8 weeks after surgery. The ultrastructural morphology and constructs of each blood product were studied by a scanning electron microscope (SEM) or calculating concentrations of platelets, fibrinogen, platelet-derived growth factor, and transforming growth factor-β. A total of five microcomputed tomography images of specimens were selected for measurement, and the area occupied by the newly formed bone as well as the horizontal bone width were measured. Moreover, decalcified tissue specimens from each defect were analyzed histologically. The median area of new bone at 4 and 8 weeks and median horizontal bone width at 8 weeks were the highest in the PPP group. However, bone maturation in the PRF and the PRP groups was more progressed than that in the PPP and control groups. By SEM findings, the PRF group showed a more highly condensed fibrin fiber network that was regularly arranged when compared with the PPP and PRP groups. The growth factors released from platelets in PRP indicated higher concentrations than that in PRF. Under more severe conditions for bone formation, as in this experiment, the growth factors released from platelets had a negative effect on bone formation. This study showed that PPP is an effective material for the preservation of sockets with buccal dehiscence. PMID:24098948

  11. Effects of platelet-poor plasma, platelet-rich plasma, and platelet-rich fibrin on healing of extraction sockets with buccal dehiscence in dogs.

    PubMed

    Hatakeyama, Ichiro; Marukawa, Eriko; Takahashi, Yukinobu; Omura, Ken

    2014-02-01

    Alveolar bone resorption generally occurs during healing after tooth extraction. This study aimed to evaluate the effects of platelet-poor plasma (PPP), platelet-rich plasma (PRP), and platelet-rich fibrin (PRF) on healing in a ridge-augmentation model of the canine socket with dehiscence of the buccal wall. The third mandibular premolars of 12 beagle dogs were extracted and a 3 mm buccal dehiscence from the alveolar crest to the buccal wall of the extraction socket was created. These sockets were then divided into four groups on the basis of the material used to fill the sockets: PPP, PRP, PRF, and control (no graft material) groups. Results were evaluated at 4 and 8 weeks after surgery. The ultrastructural morphology and constructs of each blood product were studied by a scanning electron microscope (SEM) or calculating concentrations of platelets, fibrinogen, platelet-derived growth factor, and transforming growth factor-β. A total of five microcomputed tomography images of specimens were selected for measurement, and the area occupied by the newly formed bone as well as the horizontal bone width were measured. Moreover, decalcified tissue specimens from each defect were analyzed histologically. The median area of new bone at 4 and 8 weeks and median horizontal bone width at 8 weeks were the highest in the PPP group. However, bone maturation in the PRF and the PRP groups was more progressed than that in the PPP and control groups. By SEM findings, the PRF group showed a more highly condensed fibrin fiber network that was regularly arranged when compared with the PPP and PRP groups. The growth factors released from platelets in PRP indicated higher concentrations than that in PRF. Under more severe conditions for bone formation, as in this experiment, the growth factors released from platelets had a negative effect on bone formation. This study showed that PPP is an effective material for the preservation of sockets with buccal dehiscence.

  12. Blood Platelets in the Progression of Alzheimer’s Disease

    PubMed Central

    Gowert, Nina S.; Donner, Lili; Chatterjee, Madhumita; Eisele, Yvonne S.; Towhid, Seyda T.; Münzer, Patrick; Walker, Britta; Ogorek, Isabella; Borst, Oliver; Grandoch, Maria; Schaller, Martin; Fischer, Jens W.; Gawaz, Meinrad; Weggen, Sascha; Lang, Florian; Jucker, Mathias; Elvers, Margitta

    2014-01-01

    Alzheimer’s disease (AD) is characterized by neurotoxic amyloid-ß plaque formation in brain parenchyma and cerebral blood vessels known as cerebral amyloid angiopathy (CAA). Besides CAA, AD is strongly related to vascular diseases such as stroke and atherosclerosis. Cerebrovascular dysfunction occurs in AD patients leading to alterations in blood flow that might play an important role in AD pathology with neuronal loss and memory deficits. Platelets are the major players in hemostasis and thrombosis, but are also involved in neuroinflammatory diseases like AD. For many years, platelets were accepted as peripheral model to study the pathophysiology of AD because platelets display the enzymatic activities to generate amyloid-ß (Aß) peptides. In addition, platelets are considered to be a biomarker for early diagnosis of AD. Effects of Aß peptides on platelets and the impact of platelets in the progression of AD remained, however, ill-defined. The present study explored the cellular mechanisms triggered by Aß in platelets. Treatment of platelets with Aß led to platelet activation and enhanced generation of reactive oxygen species (ROS) and membrane scrambling, suggesting enhanced platelet apoptosis. More important, platelets modulate soluble Aß into fibrillar structures that were absorbed by apoptotic but not vital platelets. This together with enhanced platelet adhesion under flow ex vivo and in vivo and platelet accumulation at amyloid deposits of cerebral vessels of AD transgenic mice suggested that platelets are major contributors of CAA inducing platelet thrombus formation at vascular amyloid plaques leading to vessel occlusion critical for cerebrovascular events like stroke. PMID:24587388

  13. Platelet Transfusion Practices in Critically Ill Children.

    PubMed

    Nellis, Marianne E; Karam, Oliver; Mauer, Elizabeth; Cushing, Melissa M; Davis, Peter J; Steiner, Marie E; Tucci, Marisa; Stanworth, Simon J; Spinella, Philip C

    2018-05-04

    Little is known about platelet transfusions in pediatric critical illness. We sought to describe the epidemiology, indications, and outcomes of platelet transfusions among critically ill children. Prospective cohort study. Multicenter (82 PICUs), international (16 countries) from September 2016 to April 2017. Children ages 3 days to 16 years prescribed a platelet transfusion in the ICU during screening days. None. Over 6 weeks, 16,934 patients were eligible, and 559 received at least one platelet transfusion (prevalence, 3.3%). The indications for transfusion included prophylaxis (67%), minor bleeding (21%), and major bleeding (12%). Thirty-four percent of prophylactic platelet transfusions were prescribed when the platelet count was greater than or equal to 50 × 10 cells/L. The median (interquartile range) change in platelet count post transfusion was 48 × 10 cells/L (17-82 × 10 cells/L) for major bleeding, 42 × 10 cells/L (16-80 × 10 cells/L) for prophylactic transfusions to meet a defined threshold, 38 × 10 cells/L (17-72 × 10 cells/L) for minor bleeding, and 25 × 10 cells/L (10-47 × 10 cells/L) for prophylaxis in patients at risk of bleeding from a device. Overall ICU mortality was 25% but varied from 18% to 35% based on indication for transfusion. Upon adjusted analysis, total administered platelet dose was independently associated with increased ICU mortality (odds ratio for each additional 1 mL/kg platelets transfused, 1.002; 95% CI, 1.001-1.003; p = 0.005). The majority of platelet transfusions are given as prophylaxis to nonbleeding children, and significant variation in platelet thresholds exists. Studies are needed to clarify appropriate indications, with focus on prophylactic transfusions.

  14. Concentration of platelets and growth factors in platelet-rich plasma from Goettingen minipigs.

    PubMed

    Jungbluth, Pascal; Grassmann, Jan-Peter; Thelen, Simon; Wild, Michael; Sager, Martin; Windolf, Joachim; Hakimi, Mohssen

    2014-01-01

    In minipigs little is known about the concentration of growth factors in plasma, despite their major role in several patho-physiological processes such as healing of fractures. This prompted us to study the concentration of platelets and selected growth factors in plasma and platelet-rich plasma (PRP) preparation of sixteen Goettingen minipigs. Platelet concentrations increased significantly in PRP in comparison to native blood plasma. Generally, significant increase in the concentration of all growth factors tested was observed in the PRP in comparison to the corresponding plasma or serum. Five of the plasma samples examined contained detectable levels of bone morphogenic protein 2 (BMP-2) whereas eleven of the plasma or serum samples contained minimal amounts of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF-bb) respectively. On the other hand variable concentrations of bone morphogenic protein 7 (BMP-7) and transforming growth factor β1 (TGF-β1) were measured in all plasma samples. In contrast, all PRP samples contained significantly increased amounts of growth factors. The level of BMP-2, BMP-7, TGF-β1, VEGF and PDGF-bb increased by 17.6, 1.5, 7.1, 7.2 and 103.3 fold, in comparison to the corresponding non-enriched preparations. Moreover significant positive correlations were found between platelet count and the concentrations of BMP-2 (r=0.62, p<0.001), TGF-β1 (r=0.85, p<0.001), VEGF (r=0.46, p<0.01) and PDGF-bb (r=0.9, p<0.001). Our results demonstrate that selected growth factors are present in the platelet-rich plasma of minipigs which might thus serve as a source of autologous growth factors.

  15. Time-dependent inhibitory effects of cGMP-analogues on thrombin-induced platelet-derived microparticles formation, platelet aggregation, and P-selectin expression

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Nygaard, Gyrid; Department of Biomedicine, University of Bergen, Bergen; Herfindal, Lars

    Highlights: • We investigated the impact of cyclic nucleotide analogues on platelet activation. • Different time dependence were found for inhibition of platelet activation. • Additive effect was found using PKA- and PKG-activating analogues. • Our results may explain some of the discrepancies reported for cNMP signalling. - Abstract: In platelets, nitric oxide (NO) activates cGMP/PKG signalling, whereas prostaglandins and adenosine signal through cAMP/PKA. Cyclic nucleotide signalling has been considered to play an inhibitory role in platelets. However, an early stimulatory effect of NO and cGMP-PKG signalling in low dose agonist-induced platelet activation have recently been suggested. Here, we investigatedmore » whether different experimental conditions could explain some of the discrepancy reported for platelet cGMP-PKG-signalling. We treated gel-filtered human platelets with cGMP and cAMP analogues, and used flow cytometric assays to detect low dose thrombin-induced formation of small platelet aggregates, single platelet disappearance (SPD), platelet-derived microparticles (PMP) and thrombin receptor agonist peptide (TRAP)-induced P-selectin expression. All four agonist-induced platelet activation phases were blocked when platelets were costimulated with the PKG activators 8-Br-PET-cGMP or 8-pCPT-cGMP and low-doses of thrombin or TRAP. However, extended incubation with 8-Br-PET-cGMP decreased its inhibition of TRAP-induced P-selectin expression in a time-dependent manner. This effect did not involve desensitisation of PKG or PKA activity, measured as site-specific VASP phosphorylation. Moreover, PKG activators in combination with the PKA activator Sp-5,6-DCL-cBIMPS revealed additive inhibitory effect on TRAP-induced P-selectin expression. Taken together, we found no evidence for a stimulatory role of cGMP/PKG in platelets activation and conclude rather that cGMP/PKG signalling has an important inhibitory function in human platelet activation.« less

  16. Role of the recombinant protein of the platelet receptor for type I collagen in the release of nitric oxide during platelet aggregation.

    PubMed

    Chiang, T M; Wang, Y B; Kang, E S

    2000-12-01

    Nitric oxide plays an important role in platelet function and platelets possess the endothelial isoform of nitric oxide synthase. Several reports have indicated that nitric oxide is released upon exposure of platelets to collagen. We have reported that a non-integrin platelet protein of 65 kDa is a receptor for type I collagen. By direct measurement of NO release from washed human platelets suspended in Tyrode buffer with a ISO-NO Mark II, World Precision Instruments, Sarasota, FL, USA, p30 sensor, type I collagen, but not ADP and epinephrine, induces the release of NO in a time-dependent manner. The production of NO is inhibited either by preincubation of type I collagen with the platelet type I collagen receptor recombinant protein or by preincubation of platelets with the antibody to the receptor protein, the anti-65 antibody. However, preincubation of platelets with anti-P-selectin and anti-glycoprotein IIb/IIIa did not affect the release of NO by platelets. These results suggest that the 65 kDa platelet receptor for type I collagen is specifically linked to the generation of NO, and that the 65 kDa platelet receptor for type I collagen plays an important new role in platelet function.

  17. Pathogen-reduced platelets for the prevention of bleeding

    PubMed Central

    Estcourt, Lise J; Malouf, Reem; Hopewell, Sally; Trivella, Marialena; Doree, Carolyn; Stanworth, Simon J; Murphy, Michael F

    2017-01-01

    Background Platelet transfusions are used to prevent and treat bleeding in people who are thrombocytopenic. Despite improvements in donor screening and laboratory testing, a small risk of viral, bacterial, or protozoal contamination of platelets remains. There is also an ongoing risk from newly emerging blood transfusion-transmitted infections for which laboratory tests may not be available at the time of initial outbreak. One solution to reduce the risk of blood transfusion-transmitted infections from platelet transfusion is photochemical pathogen reduction, in which pathogens are either inactivated or significantly depleted in number, thereby reducing the chance of transmission. This process might offer additional benefits, including platelet shelf-life extension, and negate the requirement for gamma-irradiation of platelets. Although current pathogen-reduction technologies have been proven to reduce pathogen load in platelet concentrates, a number of published clinical studies have raised concerns about the effectiveness of pathogen-reduced platelets for post-transfusion platelet count recovery and the prevention of bleeding when compared with standard platelets. This is an update of a Cochrane review first published in 2013. Objectives To assess the effectiveness of pathogen-reduced platelets for the prevention of bleeding in people of any age requiring platelet transfusions. Search methods We searched for randomised controlled trials (RCTs) in the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2016, Issue 9), MEDLINE (from 1946), Embase (from 1974), CINAHL (from 1937), the Transfusion Evidence Library (from 1950), and ongoing trial databases to 24 October 2016. Selection criteria We included RCTs comparing the transfusion of pathogen-reduced platelets with standard platelets, or comparing different types of pathogen-reduced platelets. Data collection and analysis We used the standard methodological procedures expected by

  18. The kinetics of unmatched and HLA-matched 111in-labelled homologous platelets in recipients with chronic marrow hypoplasia and anti-platelet immunity.

    PubMed

    Peters, A M; Porter, J B; Saverymuttu, S H; Malik, F; Zuiable, A; Lavender, J P; Schwarz, G; Lewis, S M; Gordon-Smith, E C

    1985-05-01

    The kinetics of homologous platelets, labelled in plasma with 111In-tropolonate, have been studied in five recipients with chronic marrow hypoplasia and severe thrombocytopenia, who were refractory to platelet transfusions as a result of alloimmunization. Mean platelet life span (MPLS), recovery, plasma 111In level and splenic and hepatic uptake kinetics were studied on two occasions, one using HLA-matched platelets and the other unmatched platelets. In each case, recovery of labelled platelets at 1 h post-injection and MPLS improved with HLA matching, although this improvement was highly variable. Only two of the five subjects would have derived any significant benefit from HLA-matched as compared with unmatched platelet transfusions. It was concluded that the need exists for additional cross-matching procedures, possibly related to platelet specific antigens, in patients who remain refractory to platelet transfusion.

  19. Platelet bioreactor: accelerated evolution of design and manufacture.

    PubMed

    Thon, Jonathan N; Dykstra, Brad J; Beaulieu, Lea M

    2017-07-01

    Platelets, responsible for clot formation and blood vessel repair, are produced by megakaryocytes in the bone marrow. Platelets are critical for hemostasis and wound healing, and are often provided following surgery, chemotherapy, and major trauma. Despite their importance, platelets today are derived exclusively from human volunteer donors. They have a shelf life of just five days, making platelet shortages common during long weekends, civic holidays, bad weather, and during major emergencies when platelets are needed most. Megakaryocytes in the bone marrow generate platelets by extruding long cytoplasmic extensions called proplatelets through gaps/fenestrations in blood vessels. Proplatelets serve as assembly lines for platelet production by sequentially releasing platelets and large discoid-shaped platelet intermediates called preplatelets into the circulation. Recent advances in platelet bioreactor development have aimed to mimic the key physiological characteristics of bone marrow, including extracellular matrix composition/stiffness, blood vessel architecture comprising tissue-specific microvascular endothelium, and shear stress. Nevertheless, how complex interactions within three-dimensional (3D) microenvironments regulate thrombopoiesis remains poorly understood, and the technical challenges associated with designing and manufacturing biomimetic microfluidic devices are often under-appreciated and under-reported. We have previously reviewed the major cell culture, platelet quality assessment, and regulatory roadblocks that must be overcome to make human platelet production possible for clinical use [1]. This review builds on our previous manuscript by: (1) detailing the historical evolution of platelet bioreactor design to recapitulate native platelet production ex vivo, and (2) identifying the associated challenges that still need to be addressed to further scale and validate these devices for commercial application. While platelets are among the first

  20. Opposing Effects of Platelet-Activating Factor and Lyso-Platelet-Activating Factor on Neutrophil and Platelet ActivationS⃞

    PubMed Central

    Welch, Emily J.; Naikawadi, Ram P.; Li, Zhenyu; Lin, Phoebe; Ishii, Satoshi; Shimizu, Takao; Tiruppathi, Chinnaswamy; Du, Xiaoping; Subbaiah, Papasani V.; Ye, Richard D.

    2009-01-01

    Platelet-activating factor (PAF) is a potent, bioactive phospholipid that acts on multiple cells and tissues through its G protein-coupled receptor (GPCR). PAF is not stored but is rapidly generated via enzymatic acetylation of the precursor 1-O-hexadecyl-2-hydroxy-sn-glycero-3-phosphocholine (lysoPAF). The bioactivity of PAF is effectively and tightly regulated by PAF acetylhydrolases, which convert PAF back to lysoPAF. Previous studies report that lysoPAF is an inactive precursor and metabolite of PAF. However, lysoPAF has not been carefully studied in its own context. Here we report that lysoPAF has an opposing effect of PAF in the activation of neutrophils and platelets. Whereas PAF potentiates neutrophil NADPH oxidase activation, lysoPAF dose-dependently inhibits this function. Inhibition by lysoPAF is not affected by the use of a PAF receptor antagonist or genetic deletion of the PAF receptor gene. The mechanism of lysoPAF-mediated inhibition of neutrophils involves an elevation in the intracellular cAMP level, and pharmacological blockade of adenylyl cyclase completely reverses the inhibitory effect of lysoPAF. In addition, lysoPAF increases intracellular cAMP levels in platelets and inhibits thrombin-induced platelet aggregation, which can be reversed by inhibition of protein kinase A. These findings identify lysoPAF as a bioactive lipid with opposing functions of PAF and suggest a novel and intrinsic regulatory mechanism for balance of the potent activity of PAF. PMID:18931035

  1. Combined aspirin and cilostazol treatment is associated with reduced platelet aggregation and prevention of exercise-induced platelet activation.

    PubMed

    Cleanthis, M; Bhattacharya, V; Smout, J; Ashour, H; Stansby, G

    2009-05-01

    Cilostazol has proven efficacy in increasing walking distance in claudicants, but it has not been demonstrated to be more effective than placebo in secondary cardiovascular prevention. The direct effect of exercise on platelet function remains less well defined. We have investigated the effect of combination treatment with aspirin and cilostazol on platelet activity in claudicants subjected to repeated treadmill exercise. Nineteen claudicants completed a double-blind, randomised, controlled, cross-over trial. Each subject received a 2-week course of aspirin (75mg) and placebo and aspirin and cilostazol (100mg twice daily). Following each 2-week treatment period, patients participated in a standardised treadmill test (3.2kmh(-1), 10 degrees incline) walking to maximal claudication distance. The exercise was repeated thrice in total, and blood was sampled before and after exercise. Platelet activation was measured using free platelet counting aggregation, flow cytometry for surface markers of platelet activation and soluble P-selectin assay. Compared to aspirin and placebo, combination treatment with aspirin and cilostazol was associated with reduced arachidonic-acid-induced platelet aggregation (p<0.01, Wilcoxon signed-rank test). Aspirin and placebo treatment were associated with elevated P-selectin expression, platelet-monocyte aggregation and reduced CD42b expression (p<0.05, Wilcoxon signed-rank test) post-exercise. No difference was seen in spontaneous platelet aggregation whilst soluble P-selectin was reduced post-exercise with combination treatment with aspirin and cilostazol (p<0.05, Wilcoxon signed-rank test). Combination treatment with aspirin and cilostazol results in suppression of platelet activation and reduces the effect of exercise on platelets. The benefit seen may be a result of cilostazol enhancing the inhibitory effect of aspirin on the cyclo-oxygenase pathway.

  2. Platelet Arachidonic Acid Deficiency May Contribute to Abnormal Platelet Function During Parenteral Fish Oil Monotherapy in a Piglet Model.

    PubMed

    Turner, Justine M; Field, Catherine J; Goruk, Sue; Wizzard, Pamela; Dicken, Bryan J; Bruce, Aisha; Wales, Paul W

    2016-05-01

    Fish oil monotherapy has been an advance for treating intestinal failure-associated liver disease (IFALD). However, such patients are at risk of bleeding complications from liver disease and because fish oil can inhibit thrombosis. We have previously reported abnormal platelet function in neonatal piglets given fish oil monotherapy during parenteral nutrition (PN). The purpose of this study was to determine if abnormal fatty acid composition of the platelets could explain the prior observed antiplatelet effect. Neonatal piglets were assigned to 2 treatments: PN with fish oil monotherapy (FO; n = 4) or PN with soy oil (SO; n = 5). On day 14, plasma was collected and platelets isolated by centrifuging. The fatty acid content in plasma and platelet plug were measured using gas liquid chromatography and compared with controls (CON; n = 5). The arachidonic acid (AA) content in the FO group was on average half that of the SO group, in both the platelets (FO, 3.5% vs SO, 7.6%; P = .021; CON, 4.5%-11%) and the plasma (FO, 3.8% vs SO, 9.2%; P = .002; CON, 6.1%-9.5%). No bleeding complications were observed for any piglets during PN treatment. Using platelet mapping, we have previously shown that neonatal piglets given fish oil monotherapy have abnormal platelet function in the AA pathway. This report demonstrates that such an abnormality can be explained by platelet AA deficiency. Platelet mapping and platelet fatty acid analysis should be undertaken in human infants treated with fish oil monotherapy during PN. © 2015 American Society for Parenteral and Enteral Nutrition.

  3. Platelet reactivity and mean platelet volume as risk markers of thrombogenesis in atrial fibrillation.

    PubMed

    Makowski, Marcin; Smorag, Ireneusz; Makowska, Joanna; Bissinger, Andrzej; Grycewicz, Tomasz; Paśnik, Jarek; Kidawa, Michal; Lubiński, Andrzej; Zielińska, Marzenna; Baj, Zbigniew

    2017-05-15

    Atrial fibrillation (AF) is associated with increased risk of thromboembolic complications. One of the markers of the increased risk of hypercoagulable state is platelet hyperreactivity. The aim of the study was to assess impact of arrhythmia on platelet reactivity. The study included 36 (mean age 48,3; range 21-60) male patients with lone atrial fibrillation, with exclusion of concomitant diseases known to trigger hypercoagulable state. The AF patients underwent cardioversion to restore sinus rhythm and were subsequently under observation for 1month. Echocardiography, ECG and blood collection was performed before cardioversion (T0) and 4weeks after successful cardioversion (T1). During the study period patients have been contacted and examined every week and 24h ECG monitoring was performed. Platelet reactivity was assessed based on changes of CD62 and CD42b expression on platelet surface after stimulation with thrombin. Also changes in MPV were assessed. In all patients sinus rhythm was maintained at the end of the study period, however in 14 patients recurrences of AF were observed, confirmed by 24h ECG monitoring (atrial fibrillation recurrence group - AFR) and 22 patients maintained sinus rhythm throughout the whole study period (SR group). Mean fluorescence intensity (MFI) of CD62 on thrombin stimulated platelets decreased significantly 4weeks after electrical cardioversion as compared to T0 (48.04±22.42 vs 41.47±16.03; p<0.01). Also MFI of CD42b on thrombin stimulated platelets decreased significantly 4weeks after electrical cardioversion as compared to T0 (22.16±10.82 vs 12.06±5.99; p<0.0001). Platelets reactivity estimated by CD 62 expression in SR group decreased significantly after 4weeks observation (58.01±15.26 vs 46.57±13.44; p<0.001) opposite to AFR group 35.66±21.87 vs 34.54±16.4; p-ns). Moreover there were significant differences between basal reactivity during AF between SR and AFR groups (58.01±15.26 vs 35.66±21.87; p-0.01). MFI of CD42

  4. Nicergoline inhibits human platelet Ca2+ signalling through triggering a microtubule‐dependent reorganization of the platelet ultrastructure

    PubMed Central

    Walford, T; Musa, F I

    2015-01-01

    Background and Purpose Recently, we demonstrated that a pericellular Ca2+ recycling system potentiates agonist‐evoked Ca2+ signalling and granule secretion in human platelets and hypothesized a role for the membrane complex (MC) in orchestrating the accumulation of Ca2+ in the pericellular region. Previous work has demonstrated that treatment with high concentrations of nicergoline may disrupt the MC through an ability to trigger a re‐organization of the dense tubular system. Experiments were therefore performed to assess whether nicergoline‐induced changes in platelet ultrastructure affects thrombin‐evoked Ca2+ fluxes and dense granule secretion. Experimental Approach Thrombin‐evoked Ca2+ fluxes were monitored in Fura‐2‐ or Fluo‐5N‐loaded human platelets, or using platelet suspensions containing Fluo‐4 or Rhod‐5N K+ salts. Fluorescence microscopy was utilized to monitor microtubule structure and intracellular Ca2+ store distribution in TubulinTracker‐ and Fluo‐5N‐loaded platelets respectively. Dense granule secretion was monitored using luciferin–luciferase. Key Results Nicergoline treatment inhibited thrombin‐evoked Ca2+ signalling and induced alterations in the microtubule structure and the distribution of intracellular Ca2+ stores in platelets. Nicergoline altered the generation and spreading of thrombin‐induced pericellular Ca2+ signals and almost completely prevented dense granule secretion. Stabilization of microtubules using taxol reversed most effects of nicergoline on platelet Ca2+ signalling and partially reversed its effects on dense granule secretion. Conclusions and Implications Nicergoline‐induced alterations to platelet ultrastructure disrupt platelet Ca2+ signalling in a manner that would be predicted if the MC had been disrupted. These data suggest that nicergoline may be a useful prototype for the discovery of novel MC‐disrupting anti‐thrombotics. PMID:26450366

  5. Platelets and hemophilia: A review of the literature.

    PubMed

    Riedl, Julia; Ay, Cihan; Pabinger, Ingrid

    2017-07-01

    Hemophilia A and B are inherited bleeding disorders due to deficiencies of the clotting factors VIII and IX, respectively. The severity of the disease correlates with remaining factor levels, although individual differences in bleeding tendency are seen despite similar factor levels. While thrombin generation is severely impaired in persons with hemophilia, primary hemostasis, i.e. platelet function, has been generally considered to be normal. However, some studies reported prolonged bleeding times in hemophilia, suggesting that also primary hemostasis is affected. In several other studies different aspects of platelet function in hemophilia have been investigated in more detail and various alterations were discovered, such as increased platelet P-selectin expression, a lower number of procoagulant, so-called 'coated' platelets, lower aggregation upon co-incubation with tissue factor, or reduced platelet contractile forces during clot formation in comparison to healthy individuals. An influence of platelet function on clinical phenotype was suggested, which might contribute in part to variations in bleeding tendency in hemophilic patients with similar factor levels. However, the available evidence is currently limited and no clear correlations between platelet function parameters and clinical phenotypes have been demonstrated. The impact of alterations of platelet function in hemophilia remains to be better defined. Another interesting role of platelets in hemophilia has been reported recently by establishing a novel gene-therapeutic strategy using platelets as a delivery system for FVIII, showing promising results in animal models. This review gives an overview on the currently published literature on platelet function and the potential roles of platelets in hemophilia. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Palladin is involved in platelet activation and arterial thrombosis.

    PubMed

    Chen, Xuejiao; Fan, Xuemei; Tan, Juan; Shi, Panlai; Wang, Xiyi; Wang, Jinjin; Kuang, Ying; Fei, Jian; Liu, Junling; Dang, Suying; Wang, Zhugang

    2017-01-01

    The dynamics of actin cytoskeleton have been shown to play a critical role during platelet activation. Palladin is an actin-associated protein, serving as a cytoskeleton scaffold to bundle actin fibers and actin cross linker. The functional role of palladin on platelet activation has not been investigated. Here, we characterized heterozygous palladin knockout (palladin +/- ) mice to elucidate the platelet-related functions of palladin. The results showed that palladin was expressed in platelets and moderate palladin deficiency accelerated hemostasis and arterial thrombosis. The aggregation of palladin +/- platelets was increased in response to low levels of thrombin, U46619, and collagen. We also observed enhanced spreading of palladin +/- platelets on immobilized fibrinogen (Fg) and increased rate of clot retraction in platelet-rich plasma (PRP) containing palladin +/- platelets. Furthermore, the activation of the small GTPase Rac1 and Cdc42, which is associated with cytoskeletal dynamics and platelet activation signalings, was increased in the spreading and aggregating palladin +/- platelets compared to that in wild type platelets. Taken together, these findings indicated that palladin is involved in platelet activation and arterial thrombosis, implying a potent role of palladin in pathophysiology of thrombotic diseases. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Implementation of buffy-coat-derived pooled platelet concentrates for internal quality control of light transmission aggregometry: a proof of concept study.

    PubMed

    Prüller, F; Rosskopf, K; Mangge, H; Mahla, E; von Lewinski, D; Weiss, E C; Riegler, A; Enko, D

    2017-12-01

    Essentials In platelet function testing, standardized internal controls (IQC) are not commercially provided. Platelet function testing was performed daily on aliquoted pooled platelet concentrates. Pooled platelet concentrates showed stability for control purposes from Monday to Friday. Pooled platelet concentrates provide the necessary steadiness to serve as IQC material. Background Standardized commercially available control material for internal quality control (IQC) of light transmission aggregometry (LTA) is still lacking. Moreover, the availability of normal blood donors to provide fresh platelets is difficult in small laboratories, where 'volunteers' may be in short supply. Objectives To evaluate the implementation of buffy-coat-derived pooled platelet concentrates (PCs) for IQC material for LTA. Methods We used buffy-coat-derived pooled PCs from the blood bank as IQC material for LTA. On each weekend one PC was prepared (> 200 mL) and aliquoted from the original storage bag on a daily basis in four baby bags (40-50 mL), which were delivered from Monday to Friday to our laboratory. The IQC measurements of at least 85 work-weeks (from Monday to Friday) were evaluated with this new IQC material. LTA was performed on a four-channel Chronolog 700 Aggregometer (Chronolog Corporation, Havertown, PA, USA) (agonists: collagen, adenosine diphosphate [ADP], arachidonic acid [AA] and thrombin receptor activator peptide-6 [TRAP-6]). Results The medians of platelet aggregation from IQC measurements with collagen, ADP and AA from Monday to Friday were 68.0-59.5, 3.0-2.0 and 51.0-50.0%, respectively, and the mean of platelet aggregation with TRAP-6 was 71.2-66.4%. Conclusions Buffy-coat-derived pooled PCs serve as a reliable and robust IQC material for LTA measurements and would be beneficial for the whole laboratory procedure and employees' safety. © 2017 International Society on Thrombosis and Haemostasis.

  8. Determinants of ABH expression on human blood platelets.

    PubMed

    Cooling, Laura L W; Kelly, Kathleen; Barton, James; Hwang, Debbie; Koerner, Theodore A W; Olson, John D

    2005-04-15

    Platelets express ABH antigens, which can adversely effect platelet transfusion recovery and survival in ABH-incompatible recipients. To date, there has been no large, comprehensive study comparing specific donor factors with ABH expression on platelet membranes and glycoconjugates. We studied ABH expression in 166 group A apheresis platelet donors by flow cytometry, Western blotting, and thin layer chromatography relative to donor age, sex, A1/A2 subgroup, and Lewis phenotype. Overall, A antigen on platelet membranes, glycoproteins, and glycosphingolipids was linked to an A1 red blood cell (RBC) phenotype. Among A1 donors, platelet ABH varied significantly between donors (0%-87%). Intradonor variability, however, was minimal, suggesting that platelet ABH expression is a stable, donor-specific characteristic, with 5% of A1 donors typing as either ABH high- or low-expressers. Group A2 donors, in contrast, possessed a Bombay-like phenotype, lacking both A and H antigens. Unlike RBCs, ABH expression on platelets may be determined primarily by H-glycosyltransferase (FUT1) activity. Identification of A2 and A1 low expressers may increase the availability and selection of crossmatched and HLA-matched platelets. Platelets from group A2 may also be a superior product for patients undergoing A/O major mismatch allogeneic progenitor cell transplantation.

  9. Antioxidants change platelet responses to various stimulating events

    PubMed Central

    Sobotková, Alžběta; Mášová-Chrastinová, Leona; Suttnar, Jiří; Štikarová, Jana; Májek, Pavel; Reicheltová, Zuzana; Kotlín, Roman; Weisel, John W.; Malý, Martin; Dyr, Jan E.

    2010-01-01

    The role of platelets in hemostasis may be influenced by alteration of the platelet redox state—the presence of antioxidants and the formation of reactive oxygen and nitrogen species. We investigated the effects of two antioxidants, resveratrol and trolox, on platelet activation. Trolox and resveratrol inhibited aggregation of washed platelets and platelet-rich plasma activated by ADP, collagen, and thrombin receptor-activating peptide. Resveratrol was a more effective agent in reducing platelet static and dynamic adhesion in comparison with trolox. The antioxidant capacity of resveratrol was, however, the same as that of trolox. After incubation of platelets with antioxidants, the resveratrol intraplatelet concentration was about five times lower than the intracellular concentration of trolox. Although both antioxidants comparably lowered hydroxyl radical and malondialdehyde production in platelets stimulated with collagen, TxB2 levels were decreased by resveratrol much more effectively than by trolox. Cyclooxygenase 1 was inhibited by resveratrol and not by trolox. Our data indicate that antioxidants, apart from nonspecific redox or radical-quenching mechanisms, inhibit platelet activation also by specific interaction with target proteins. The results also show the importance of studying platelet activation under conditions of real blood flow in contact with reactive surfaces, e.g., using dynamic adhesion experiments. PMID:19766712

  10. Antioxidants change platelet responses to various stimulating events.

    PubMed

    Sobotková, Alzbeta; Másová-Chrastinová, Leona; Suttnar, Jirí; Stikarová, Jana; Májek, Pavel; Reicheltová, Zuzana; Kotlín, Roman; Weisel, John W; Malý, Martin; Dyr, Jan E

    2009-12-15

    The role of platelets in hemostasis may be influenced by alteration of the platelet redox state-the presence of antioxidants and the formation of reactive oxygen and nitrogen species. We investigated the effects of two antioxidants, resveratrol and trolox, on platelet activation. Trolox and resveratrol inhibited aggregation of washed platelets and platelet-rich plasma activated by ADP, collagen, and thrombin receptor-activating peptide. Resveratrol was a more effective agent in reducing platelet static and dynamic adhesion in comparison with trolox. The antioxidant capacity of resveratrol was, however, the same as that of trolox. After incubation of platelets with antioxidants, the resveratrol intraplatelet concentration was about five times lower than the intracellular concentration of trolox. Although both antioxidants comparably lowered hydroxyl radical and malondialdehyde production in platelets stimulated with collagen, TxB(2) levels were decreased by resveratrol much more effectively than by trolox. Cyclooxygenase 1 was inhibited by resveratrol and not by trolox. Our data indicate that antioxidants, apart from nonspecific redox or radical-quenching mechanisms, inhibit platelet activation also by specific interaction with target proteins. The results also show the importance of studying platelet activation under conditions of real blood flow in contact with reactive surfaces, e.g., using dynamic adhesion experiments.

  11. In vitro platelet activation, aggregation and platelet-granulocyte complex formation induced by surface modified single-walled carbon nanotubes.

    PubMed

    Fent, János; Bihari, Péter; Vippola, Minnamari; Sarlin, Essi; Lakatos, Susan

    2015-08-01

    Surface modification of single-walled carbon nanotubes (SWCNTs) such as carboxylation, amidation, hydroxylation and pegylation is used to reduce the nanotube toxicity and render them more suitable for biomedical applications than their pristine counterparts. Toxicity can be manifested in platelet activation as it has been shown for SWCNTs. However, the effect of various surface modifications on the platelet activating potential of SWCNTs has not been tested yet. In vitro platelet activation (CD62P) as well as the platelet-granulocyte complex formation (CD15/CD41 double positivity) in human whole blood were measured by flow cytometry in the presence of 0.1mg/ml of pristine or various surface modified SWCNTs. The effect of various SWCNTs was tested by whole blood impedance aggregometry, too. All tested SWCNTs but the hydroxylated ones activate platelets and promote platelet-granulocyte complex formation in vitro. Carboxylated, pegylated and pristine SWCNTs induce whole blood aggregation as well. Although pegylation is preferred from biomedical point of view, among the samples tested by us pegylated SWCNTs induced far the most prominent activation and a well detectable aggregation of platelets in whole blood. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Platelet interactions in thrombosis.

    PubMed

    Andrews, Robert K; Gardiner, Elizabeth E; Shen, Yang; Berndt, Michael C

    2004-01-01

    Patho/physiological platelet aggregate (thrombus) formation is initiated by engagement of platelet surface receptors, glycoprotein (GP)Ib-IX-V and GPVI that bind von Willebrand factor or collagen. Although beneficial in response to vascular injury by preventing blood loss (haemostasis), platelet aggregation in a sclerotic coronary artery or other diseased blood vessel (thrombosis) can cause thrombotic diseases like heart attack and stroke. At the molecular level, ligand interactions with GPIb-IX-V or GPVI trigger signalling responses, including elevation of cytosolic Ca2+, dissociation of calmodulin from their cytoplasmic domains, cytoskeletal actin-filament rearrangements, activation of src-family kinases or PI 3-kinase, and 'inside-out' activation of the integrin, alphaIIbbeta3 (GPIIb-llla), that binds von Willebrand factor or fibrinogen and mediates platelet aggregation. Furthermore, emerging evidence supports a topographical co-association of these receptors of the leucine-rich repeat family (GPIb-IX-V) and immunoglobulin superfamily (GPVI) in an adhesive cluster or 'adhesosome'. This arrangement may underlie common mechanisms of initiating thrombus formation in haemostasis or thrombotic disease.

  13. Identification of platelet refractoriness in oncohematologic patients

    PubMed Central

    Ferreira, Aline Aparecida; Zulli, Roberto; Soares, Sheila; de Castro, Vagner; Moraes-Souza, Helio

    2011-01-01

    OBJECTIVES: To identify the occurrence and the causes of platelet refractoriness in oncohematologic patients. INTRODUCTION: Platelet refractoriness (unsatisfactory post-transfusion platelet increment) is a severe problem that impairs the treatment of oncohematologic patients and is not routinely investigated in most Brazilian services. METHODS: Forty-four episodes of platelet concentrate transfusion were evaluated in 16 patients according to the following parameters: corrected count increment, clinical conditions and detection of anti-platelet antibodies by the platelet immunofluorescence test (PIFT) and panel reactive antibodies against human leukocyte antigen class I (PRA-HLA). RESULTS: Of the 16 patients evaluated (median age: 53 years), nine (56%) were women, seven of them with a history of pregnancy. An unsatisfactory increment was observed in 43% of the transfusion events, being more frequent in transfusions of random platelet concentrates (54%). Platelet refractoriness was confirmed in three patients (19%), who presented immunologic and non-immunologic causes. Alloantibodies were identified in eight patients (50%) by the PIFT and in three (19%) by the PRA-HLA. Among alloimmunized patients, nine (64%) had a history of transfusion, and three as a result of pregnancy (43%). Of the former, two were refractory (29%). No significant differences were observed, probably as a result of the small sample size. CONCLUSION: The high rate of unsatisfactory platelet increment, refractoriness and alloimmunization observed support the need to set up protocols for the investigation of this complication in all chronically transfused patients, a fundamental requirement for the guarantee of adequate management. PMID:21437433

  14. Human Cancer and Platelet Interaction, a Potential Therapeutic Target.

    PubMed

    Wang, Shike; Li, Zhenyu; Xu, Ren

    2018-04-20

    Cancer patients experience a four-fold increase in thrombosis risk, indicating that cancer development and progression are associated with platelet activation. Xenograft experiments and transgenic mouse models further demonstrate that platelet activation and platelet-cancer cell interaction are crucial for cancer metastasis. Direct or indirect interaction of platelets induces cancer cell plasticity and enhances survival and extravasation of circulating cancer cells during dissemination. In vivo and in vitro experiments also demonstrate that cancer cells induce platelet aggregation, suggesting that platelet-cancer interaction is bidirectional. Therefore, understanding how platelets crosstalk with cancer cells may identify potential strategies to inhibit cancer metastasis and to reduce cancer-related thrombosis. Here, we discuss the potential function of platelets in regulating cancer progression and summarize the factors and signaling pathways that mediate the cancer cell-platelet interaction.

  15. Advances and controversies in neonatal ICU platelet transfusion practice.

    PubMed

    Christensen, Robert D

    2008-01-01

    Some of the platelet transfusions currently given to NICU patients are unnecessary and convey no benefits. Although ordered with good intentions, unnecessary platelet transfusions carry known and unknown risks. Identifying and eliminating any unnecessary platelet transfusions in NICUs would be a step toward better care, lower costs, and more careful preservation of blood component resources. A renewed interest in platelet transfusion studies is needed, if essential data is to be gathered to improve NICU platelet transfusion practice. Retrospective studies can be of value: for instance, seeking associations between bleeding events and platelet counts can suggest the possibility of cause and effect relationships. Such studies might identify approximate platelet count levels that convey high hemorrhagic risk and might help focus future prospective trials. Prospective indirect studies also can be of value, for instance, measuring the template bleeding time and the PFA-100 closure time as a function of platelet count and perhaps as a function of circulating platelet mass, and would provide new information with relevance to platelet transfusion benefits. Such studies might give a better awareness of how low the platelet count can fall before platelet plug formation is impaired. It seems inescapable, however, that new, multicentered, randomized, prospective studies are needed, where NICU patients are assigned different platelet transfusion triggers and then carefully tracked for bleeding events and long-term neurodevelopmental outcomes. Only that type of study is likely to generate the evidence base needed for widespread implementation of improvements in NICU platelet transfusion practice.

  16. 21 CFR 864.5700 - Automated platelet aggregation system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... addition of an aggregating reagent to a platelet-rich plasma. (b) Classification. Class II (performance... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Automated platelet aggregation system. 864.5700... § 864.5700 Automated platelet aggregation system. (a) Identification. An automated platelet aggregation...

  17. 21 CFR 864.5700 - Automated platelet aggregation system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... addition of an aggregating reagent to a platelet-rich plasma. (b) Classification. Class II (performance... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Automated platelet aggregation system. 864.5700... § 864.5700 Automated platelet aggregation system. (a) Identification. An automated platelet aggregation...

  18. 21 CFR 864.5700 - Automated platelet aggregation system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... addition of an aggregating reagent to a platelet-rich plasma. (b) Classification. Class II (performance... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Automated platelet aggregation system. 864.5700... § 864.5700 Automated platelet aggregation system. (a) Identification. An automated platelet aggregation...

  19. 21 CFR 864.5700 - Automated platelet aggregation system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... addition of an aggregating reagent to a platelet-rich plasma. (b) Classification. Class II (performance... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Automated platelet aggregation system. 864.5700... § 864.5700 Automated platelet aggregation system. (a) Identification. An automated platelet aggregation...

  20. 21 CFR 864.5700 - Automated platelet aggregation system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... addition of an aggregating reagent to a platelet-rich plasma. (b) Classification. Class II (performance... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Automated platelet aggregation system. 864.5700... § 864.5700 Automated platelet aggregation system. (a) Identification. An automated platelet aggregation...

  1. In vivo quantitation of platelet deposition on human peripheral arterial bypass grafts using indium-111-labeled platelets. Effect of dipyridamole and aspirin

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pumphrey, C.W.; Chesebro, J.H.; Dewanjee, M.K.

    Indium-111-labeled autologous platelets, injected 48 hours after operation, were used to evaluate the thrombogenicity of prosthetic material and the effect of platelet inhibitor therapy in vivo. Dacron double-velour (Microvel) aortofemoral artery bifurcation grafts were placed in 16 patients and unilateral polytetrafluoroethylene femoropopliteal grafts were placed in 10 patients. Half the patients in each group received platelet inhibitors before operation (dipyridamole, 100 mg 4 times a day) and after operation (dipyridamole, 75 mg, and acetylsalicylic acid, 325 mg 3 times a day); the rest of the patients served as control subjects. Five-minute scintigrams of the graft region were taken with amore » gamma camera interfaced with a computer 48, 72, and 96 hours after injection of the labeled platelets. Platelet deposition was estimated from the radioactivities of the grafts and expressed as counts per 100 pixels per microcurie injected. Dipyridamole and aspirin therapy significantly reduced the number of platelets deposited on Dacron grafts and prevented platelet accumulation over 3 days. With the small amount of platelet deposition on polytetrafluoroethylene femoropopliteal artery grafts even in control patients, platelet inhibitor therapy had no demonstrable effect on platelet deposition on these grafts. It is concluded that (1) platelet deposition on vascular grafts in vivo can be quantitated by noninvasive methods, and (2) dipyridamole and aspirin therapy reduced platelet deposition on Dacron aortofemoral artery grafts.« less

  2. Heparin-associated thrombocytopenia: antibody binding specificity to platelet antigens.

    PubMed

    Lynch, D M; Howe, S E

    1985-11-01

    Sera from four patients with heparin-associated thrombocytopenia (HAT) were evaluated by a quantitative enzyme-linked immunosorbent assay (ELISA) to detect heparin-dependent serum platelet-bindable immunoglobulin (S-PBIg) and by Western blotting and immunoprecipitation to investigate the specificity of the antibody binding. All HAT sera showed mildly increased S-PBIg (mean, 7.8 fg per platelet; normal, less than 6.0 fg per platelet) to intact target platelets in the ELISA, which was markedly increased in the presence of heparin (mean, 20.9 fg per platelet). This increase was 20-fold greater than normal control sera, which showed a mean differential increase of only 0.5 fg per platelet. Immunoglobulin binding specificity to platelet antigens was investigated using sodium dodecyl sulfate-polyacrylamide gel electrophoresis of platelet lysate with transfer of the platelet fractions onto nitrocellulose strips (Western blotting) and subsequent immunoassay using HAT and normal sera. In the presence of heparin, the four HAT patients demonstrated increased binding of immunoglobulin to platelet antigens of apparent molecular weights of 180, 124, and 82 kd. Radiolabeled heparin when incubated with HAT sera, normal sera, or albumin blanks bound to platelet proteins of the same apparent molecular weights. These observations are consistent with current hypotheses suggesting that HAT antibody is directed to heparin-platelet complexes or, alternatively, that heparin induces conformational change of antigenic sites on the platelet membrane.

  3. Evaluating platelet aggregation dynamics from laser speckle fluctuations.

    PubMed

    Hajjarian, Zeinab; Tshikudi, Diane M; Nadkarni, Seemantini K

    2017-07-01

    Platelets are key to maintaining hemostasis and impaired platelet aggregation could lead to hemorrhage or thrombosis. We report a new approach that exploits laser speckle intensity fluctuations, emanated from a drop of platelet-rich-plasma (PRP), to profile aggregation. Speckle fluctuation rate is quantified by the speckle intensity autocorrelation, g 2 (t) , from which the aggregate size is deduced. We first apply this approach to evaluate polystyrene bead aggregation, triggered by salt. Next, we assess dose-dependent platelet aggregation and inhibition in human PRP spiked with adenosine diphosphate and clopidogrel. Additional spatio-temporal speckle analyses yield 2-dimensional maps of particle displacements to visualize platelet aggregate foci within minutes and quantify aggregation dynamics. These findings demonstrate the unique opportunity for assessing platelet health within minutes for diagnosing bleeding disorders and monitoring anti-platelet therapies.

  4. Platelet activation suppresses HIV-1 infection of T cells

    PubMed Central

    2013-01-01

    Background Platelets, anucleate cell fragments abundant in human blood, can capture HIV-1 and platelet counts have been associated with viral load and disease progression. However, the impact of platelets on HIV-1 infection of T cells is unclear. Results We found that platelets suppress HIV-1 spread in co-cultured T cells in a concentration-dependent manner. Platelets containing granules inhibited HIV-1 spread in T cells more efficiently than degranulated platelets, indicating that the granule content might exert antiviral activity. Indeed, supernatants from activated and thus degranulated platelets suppressed HIV-1 infection. Infection was inhibited at the stage of host cell entry and inhibition was independent of the viral strain or coreceptor tropism. In contrast, blockade of HIV-2 and SIV entry was less efficient. The chemokine CXCL4, a major component of platelet granules, blocked HIV-1 entry and neutralization of CXCL4 in platelet supernatants largely abrogated their anti-HIV-1 activity. Conclusions Release of CXCL4 by activated platelets inhibits HIV-1 infection of adjacent T cells at the stage of virus entry. The inhibitory activity of platelet-derived CXCL4 suggests a role of platelets in the defense against infection by HIV-1 and potentially other pathogens. PMID:23634812

  5. Platelet activation suppresses HIV-1 infection of T cells.

    PubMed

    Solomon Tsegaye, Theodros; Gnirß, Kerstin; Rahe-Meyer, Niels; Kiene, Miriam; Krämer-Kühl, Annika; Behrens, Georg; Münch, Jan; Pöhlmann, Stefan

    2013-05-01

    Platelets, anucleate cell fragments abundant in human blood, can capture HIV-1 and platelet counts have been associated with viral load and disease progression. However, the impact of platelets on HIV-1 infection of T cells is unclear. We found that platelets suppress HIV-1 spread in co-cultured T cells in a concentration-dependent manner. Platelets containing granules inhibited HIV-1 spread in T cells more efficiently than degranulated platelets, indicating that the granule content might exert antiviral activity. Indeed, supernatants from activated and thus degranulated platelets suppressed HIV-1 infection. Infection was inhibited at the stage of host cell entry and inhibition was independent of the viral strain or coreceptor tropism. In contrast, blockade of HIV-2 and SIV entry was less efficient. The chemokine CXCL4, a major component of platelet granules, blocked HIV-1 entry and neutralization of CXCL4 in platelet supernatants largely abrogated their anti-HIV-1 activity. Release of CXCL4 by activated platelets inhibits HIV-1 infection of adjacent T cells at the stage of virus entry. The inhibitory activity of platelet-derived CXCL4 suggests a role of platelets in the defense against infection by HIV-1 and potentially other pathogens.

  6. Ristocetin induces phosphorylated-HSP27 (HSPB1) release from the platelets of type 2 DM patients: Anti-platelet agent-effect on the release.

    PubMed

    Tokuda, Haruhiko; Kuroyanagi, Gen; Onuma, Takashi; Enomoto, Yukiko; Doi, Tomoaki; Iida, Hiroki; Otsuka, Takanobu; Ogura, Shinji; Iwama, Toru; Kojima, Kumi; Kozawa, Osamu

    2018-04-01

    It has been previously reported that HSP27 is released from platelets in type 2 diabetes mellitus (DM) patients according to phosphorylation. In the present study, we investigated the effect of ristocetin, a glycoprotein (GP)Ib/IX/V activator, on the release of HSP27 and the effect of anti-platelet agents, such as acetylsalicylic acid (ASA), on this release. Forty-six patients with type 2 DM were recruited, and classified into two groups depending on administration of anti-platelet agents, resulting in 31 patients without these agents (control group) and 15 patients with them (anti-platelet group). Ristocetin potently induced the aggregation of platelets in the two groups. Ristocetin-induced changes of the area under the curve of light transmittance and the ratio of the size of platelet aggregates in the anti-platelet group were slightly different from those in the control group. On the other hand, the levels of phosphorylated-HSP27 induced by ristocetin in the platelets from a patient of the anti-platelet group taking ASA were significantly lower than those from a patient of the control group. The levels of HSP27 release from the ristocetin-stimulated platelets were significantly correlated with the levels of phosphorylated-HSP27 in the platelets from patients in the two groups. The levels of HSP27 release and those of platelet-derived growth factor-AB (PDGF-AB) secretion stimulated by ristocetin in the anti-platelet group were lower than those in the control group. In addition, the levels of HSP27 release and those of PDGF-AB secretion stimulated by ADP in the anti-platelet group were lower than those in the control group. These results strongly suggest that anti-platelet agents inhibit the HSP27 release from platelets stimulated by ristocetin but not the aggregation in type 2 DM patients.

  7. Thrombopoietin contributes to enhanced platelet activation in cigarette smokers.

    PubMed

    Lupia, Enrico; Bosco, Ornella; Goffi, Alberto; Poletto, Cesare; Locatelli, Stefania; Spatola, Tiziana; Cuccurullo, Alessandra; Montrucchio, Giuseppe

    2010-05-01

    Thrombopoietin (TPO) is a humoral growth factor that primes platelet activation in response to several agonists. We recently showed that TPO enhances platelet activation in unstable angina and sepsis. Aim of this study was to investigate the role of TPO in platelet function abnormalities described in cigarette smokers. In a case-control study we enrolled 20 healthy cigarette smokers and 20 nonsmokers, and measured TPO and C-reactive protein (CRP), as well as platelet-leukocyte binding and P-selectin expression. In vitro we evaluated the priming activity of smoker or control plasma on platelet activation, and the role of TPO in this effect. We then studied the effects of acute smoking and smoking cessation on TPO levels and platelet activation indices. Chronic cigarette smokers had higher circulating TPO levels than nonsmoking controls, as well as increased platelet-leukocyte binding, P-selectin expression, and CRP levels. Serum cotinine concentrations correlated with TPO concentrations, platelet-monocyte aggregates and P-selectin expression. In addition, TPO levels significantly correlated with ex vivo platelet-monocyte aggregation and P-selectin expression. In vitro, the plasma from cigarette smokers, but not from nonsmoking controls, primed platelet-monocyte binding, which was reduced when an inhibitor of TPO was used. We also found that acute smoking slightly increased TPO levels, but did not affect platelet-leukocyte binding, whereas smoking cessation induced a significant decrease in both circulating TPO and platelet-leukocyte aggregation. Elevated TPO contributes to enhance platelet activation and platelet-monocyte cross-talk in cigarette smokers. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.

  8. The important role of von Willebrand factor in platelet-derived FVIII gene therapy for murine hemophilia A in the presence of inhibitory antibodies.

    PubMed

    Shi, Q; Schroeder, J A; Kuether, E L; Montgomery, R R

    2015-07-01

    Our previous studies have demonstrated that targeting FVIII expression to platelets results in FVIII storage together with von Willebrand factor (VWF) in platelet α-granules and that platelet-derived FVIII (2bF8) corrects the murine hemophilia A phenotype even in the presence of high-titer anti-FVIII inhibitory antibodies (inhibitors). To explore how VWF has an impact on platelet gene therapy for hemophilia A with inhibitors. 2bF8 transgenic mice in the FVIII(-/-) background (2bF8(tg+/-) F8(-/-) ) with varying VWF phenotypes were used in this study. Animals were analyzed by VWF ELISA, FVIII activity assay, Bethesda assay and tail clip survival test. Only 18% of 2bF8(tg+/-) F8(-/-) VWF(-/-) animals, in which VWF was deficient, survived the tail clip challenge with inhibitor titers of 3-8000 BU mL(-1) . In contrast, 82% of 2bF8(tg+/-) F8(-/-) VWF(+/+) mice, which had normal VWF levels, survived tail clipping with inhibitor titers of 10-50,000 BU mL(-1) . All 2bF8(tg+/-) F8(-/-) VWF(-/-) mice without inhibitors survived tail clipping and no VWF(-/-) F8(-/-) mice survived this challenge. Because VWF is synthesized by endothelial cells and megakaryocytes and is distributed in both plasma and platelets in peripheral blood, we further investigated the effect of each compartment of VWF on platelet-FVIII gene therapy for hemophilia A with inhibitors. In the presence of inhibitors, 42% of animals survived tail clipping in the group with plasma-VWF and 50% survived in the platelet-VWF group. VWF is essential for platelet gene therapy for hemophilia A with inhibitors. Both platelet-VWF and plasma-VWF are required for optimal platelet-derived FVIII gene therapy for hemophilia A in the presence of inhibitors. © 2015 International Society on Thrombosis and Haemostasis.

  9. Equid Herpesvirus Type 1 Activates Platelets

    PubMed Central

    Stokol, Tracy; Yeo, Wee Ming; Burnett, Deborah; DeAngelis, Nicole; Huang, Teng; Osterrieder, Nikolaus; Catalfamo, James

    2015-01-01

    Equid herpesvirus type 1 (EHV-1) causes outbreaks of abortion and neurological disease in horses. One of the main causes of these clinical syndromes is thrombosis in placental and spinal cord vessels, however the mechanism for thrombus formation is unknown. Platelets form part of the thrombus and amplify and propagate thrombin generation. Here, we tested the hypothesis that EHV-1 activates platelets. We found that two EHV-1 strains, RacL11 and Ab4 at 0.5 or higher plaque forming unit/cell, activate platelets within 10 minutes, causing α-granule secretion (surface P-selectin expression) and platelet microvesiculation (increased small events double positive for CD41 and Annexin V). Microvesiculation was more pronounced with the RacL11 strain. Virus-induced P-selectin expression required plasma and 1.0 mM exogenous calcium. P-selectin expression was abolished and microvesiculation was significantly reduced in factor VII- or X-deficient human plasma. Both P-selectin expression and microvesiculation were re-established in factor VII-deficient human plasma with added purified human factor VIIa (1 nM). A glycoprotein C-deficient mutant of the Ab4 strain activated platelets as effectively as non-mutated Ab4. P-selectin expression was abolished and microvesiculation was significantly reduced by preincubation of virus with a goat polyclonal anti-rabbit tissue factor antibody. Infectious virus could be retrieved from washed EHV-1-exposed platelets, suggesting a direct platelet-virus interaction. Our results indicate that EHV-1 activates equine platelets and that α-granule secretion is a consequence of virus-associated tissue factor triggering factor X activation and thrombin generation. Microvesiculation was only partly tissue factor and thrombin-dependent, suggesting the virus causes microvesiculation through other mechanisms, potentially through direct binding. These findings suggest that EHV-1-induced platelet activation could contribute to the thrombosis that occurs in

  10. Platelets in liver disease, cancer and regeneration.

    PubMed

    Kurokawa, Tomohiro; Ohkohchi, Nobuhiro

    2017-05-14

    Although viral hepatitis treatments have evolved over the years, the resultant liver cirrhosis still does not completely heal. Platelets contain proteins required for hemostasis, as well as many growth factors required for organ development, tissue regeneration and repair. Thrombocytopenia, which is frequently observed in patients with chronic liver disease (CLD) and cirrhosis, can manifest from decreased thrombopoietin production and accelerated platelet destruction caused by hypersplenism; however, the relationship between thrombocytopenia and hepatic pathogenesis, as well as the role of platelets in CLD, is poorly understood. In this paper, experimental evidence of platelets improving liver fibrosis and accelerating liver regeneration is summarized and addressed based on studies conducted in our laboratory and current progress reports from other investigators. In addition, we describe our current perspective based on the results of these studies. Platelets improve liver fibrosis by inactivating hepatic stellate cells, which decreases collagen production. The regenerative effect of platelets in the liver involves a direct effect on hepatocytes, a cooperative effect with liver sinusoidal endothelial cells, and a collaborative effect with Kupffer cells. Based on these observations, we ascertained the direct effect of platelet transfusion on improving several indicators of liver function in patients with CLD and liver cirrhosis. However, unlike the results of our previous clinical study, the smaller incremental changes in liver function in patients with CLD who received eltrombopag for 6 mo were due to patient selection from a heterogeneous population. We highlight the current knowledge concerning the role of platelets in CLD and cancer and anticipate a novel application of platelet-based clinical therapies to treat liver disease.

  11. Influence of mental stress on platelet bioactivity

    PubMed Central

    Koudouovoh-Tripp, Pia; Sperner-Unterweger, Barbara

    2012-01-01

    It is well established that various mental stress conditions contribute, or at least influence, underlying pathophysiological mechanisms in somatic, as well as in psychiatric disorders; blood platelets are supposed to represent a possible link in this respect. The anculeated platelets are the smallest corpuscular elements circulating in the human blood. They display different serotonergic markers which seem to reflect the central nervous serotonin metabolism. They are known as main effectors in haematological processes but recent research highlights their role in the innate and adaptive immune system. Platelets are containing a multitude of pro-inflammatory and immune-modulatory bioactive compounds in their granules and are expressing immune-competent surface markers. Research gives hint that platelets activation and reactivity is increased by mental stress. This leads to enhanced cross talk with the immune system via paracrine secretion, receptor interaction and formation of platelet leucocyte-aggregates. Recently it has been demonstrated that the immune system can have a remarkable impact in the development of psychiatric disorders. Therefore platelets represent an interesting research area in psychiatry and their role as a possible biomarker has been investigated. We review the influence of mental stress on what is termed platelet bioactivity in this article, which subsumes the mainly immune-modulatory activity of platelets in healthy volunteers, elderly persons with chronic care-giving strain, patients with cardiovascular diseases who are prone to psychosocial stress, as well as in patients with posttraumatic stress disorder. Research data suggest that stress enhances platelet activity, reactivity and immune-modulatory capacities. PMID:24175179

  12. Evaluating platelet aggregation dynamics from laser speckle fluctuations

    PubMed Central

    Hajjarian, Zeinab; Tshikudi, Diane M.; Nadkarni, Seemantini K.

    2017-01-01

    Platelets are key to maintaining hemostasis and impaired platelet aggregation could lead to hemorrhage or thrombosis. We report a new approach that exploits laser speckle intensity fluctuations, emanated from a drop of platelet-rich-plasma (PRP), to profile aggregation. Speckle fluctuation rate is quantified by the speckle intensity autocorrelation, g2(t), from which the aggregate size is deduced. We first apply this approach to evaluate polystyrene bead aggregation, triggered by salt. Next, we assess dose-dependent platelet aggregation and inhibition in human PRP spiked with adenosine diphosphate and clopidogrel. Additional spatio-temporal speckle analyses yield 2-dimensional maps of particle displacements to visualize platelet aggregate foci within minutes and quantify aggregation dynamics. These findings demonstrate the unique opportunity for assessing platelet health within minutes for diagnosing bleeding disorders and monitoring anti-platelet therapies. PMID:28717586

  13. Platelet Factor 4 Mediates Inflammation in Cerebral Malaria

    PubMed Central

    Srivastava, Kalyan; Cockburn, Ian A.; Swaim, AnneMarie; Thompson, Laura E.; Tripathi, Abhai; Fletcher, Craig A.; Shirk, Erin M.; Sun, Henry; Kowalska, M. Anna; Fox-Talbot, Karen; Sullivan, David; Zavala, Fidel; Morrell, Craig N.

    2008-01-01

    Summary Cerebral malaria is a major complication of Plasmodium falciparum infection in children. The pathogenesis of cerebral malaria involves vascular inflammation, immune stimulation and obstruction of cerebral capillaries. Platelets have a prominent role in both immune responses and vascular obstruction. We now demonstrate that the platelet derived chemokine, platelet factor 4 (PF4)/CXCL4, promotes the development of experimental cerebral malaria. Plasmodium infected red blood cells (RBC) activated platelets independent of vascular effects, resulting in increased plasma PF4. PF4 or CXCR3 null mice had less ECM, decreased brain T-cell recruitment, and platelet depletion or aspirin treatment reduced the development of ECM. We conclude that Plasmodium infected RBC can activate platelets and platelet derived PF4 then contributes to immune activation and T-cell trafficking as part of the pathogenesis of ECM. PMID:18692777

  14. Platelets and Multi-Organ Failure in Sepsis.

    PubMed

    Greco, Elisabetta; Lupia, Enrico; Bosco, Ornella; Vizio, Barbara; Montrucchio, Giuseppe

    2017-10-20

    Platelets have received increasing attention for their role in the pathophysiology of infectious disease, inflammation, and immunity. In sepsis, a low platelet count is a well-known biomarker for disease severity and more recently authors have focused their attention on the active role of platelets in the pathogenesis of multi-organ failure. Septic shock is characterised by a dysregulated inflammatory response, which can impair the microcirculation and lead to organ injury. Being at the crossroads between the immune system, clotting cascade, and endothelial cells, platelets seem to be an appealing central mediator and possible therapeutic target in sepsis. This review focuses on the pathogenic role of platelets in septic organ dysfunction in humans and animal models.

  15. Platelets and Multi-Organ Failure in Sepsis

    PubMed Central

    Greco, Elisabetta; Lupia, Enrico; Bosco, Ornella; Vizio, Barbara; Montrucchio, Giuseppe

    2017-01-01

    Platelets have received increasing attention for their role in the pathophysiology of infectious disease, inflammation, and immunity. In sepsis, a low platelet count is a well-known biomarker for disease severity and more recently authors have focused their attention on the active role of platelets in the pathogenesis of multi-organ failure. Septic shock is characterised by a dysregulated inflammatory response, which can impair the microcirculation and lead to organ injury. Being at the crossroads between the immune system, clotting cascade, and endothelial cells, platelets seem to be an appealing central mediator and possible therapeutic target in sepsis. This review focuses on the pathogenic role of platelets in septic organ dysfunction in humans and animal models. PMID:29053592

  16. Comparison of growth factor and platelet concentration from commercial platelet-rich plasma separation systems.

    PubMed

    Castillo, Tiffany N; Pouliot, Michael A; Kim, Hyeon Joo; Dragoo, Jason L

    2011-02-01

    Clinical studies claim that platelet-rich plasma (PRP) shortens recovery times because of its high concentration of growth factors that may enhance the tissue repair process. Most of these studies obtained PRP using different separation systems, and few analyzed the content of the PRP used as treatment. This study characterized the composition of single-donor PRP produced by 3 commercially available PRP separation systems. Controlled laboratory study. Five healthy humans donated 100 mL of blood, which was processed to produce PRP using 3 PRP concentration systems (MTF Cascade, Arteriocyte Magellan, Biomet GPS III). Platelet, white blood cell (WBC), red blood cell, and fibrinogen concentrations were analyzed by automated systems in a clinical laboratory, whereas ELISA determined the concentrations of platelet-derived growth factor αβ and ββ (PDGF-αβ, PDGF-ββ), transforming growth factor β1 (TGF-β1), and vascular endothelial growth factor (VEGF). There was no significant difference in mean PRP platelet, red blood cell, active TGF-β1, or fibrinogen concentrations among PRP separation systems. There was a significant difference in platelet capture efficiency. The highest platelet capture efficiency was obtained with Cascade, which was comparable with Magellan but significantly higher than GPS III. There was a significant difference among all systems in the concentrations of WBC, PDGF-αβ, PDGF-ββ, and VEGF. The Cascade system concentrated leukocyte-poor PRP, compared with leukocyte-rich PRP from the GPS III and Magellan systems. The GPS III and Magellan concentrate leukocyte-rich PRP, which results in increased concentrations of WBCs, PDGF-αβ, PDGF-ββ, and VEGF as compared with the leukocyte-poor PRP from Cascade. Overall, there was no significant difference among systems in the platelet concentration, red blood cell, active TGF-β1, or fibrinogen levels. Products from commercially available PRP separation systems produce differing concentrations of

  17. Higher platelet reactivity and platelet-monocyte complex formation in Gram-positive sepsis compared to Gram-negative sepsis.

    PubMed

    Tunjungputri, Rahajeng N; van de Heijden, Wouter; Urbanus, Rolf T; de Groot, Philip G; van der Ven, Andre; de Mast, Quirijn

    2017-09-01

    Platelets may play a role in the high risk for vascular complications in Gram-positive sepsis. We compared the platelet reactivity of 15 patients with Gram-positive sepsis, 17 with Gram-negative sepsis and 20 healthy controls using a whole blood flow cytometry-based assay. Patients with Gram-positive sepsis had the highest median fluorescence intensity (MFI) of the platelet membrane expression of P-selectin upon stimulation with high dose adenosine diphosphate (ADP; P = 0.002 vs. Gram-negative and P = 0.005 vs. control groups) and cross-linked collagen-related peptide (CRP-XL; P = 0.02 vs. Gram-negative and P = 0.0001 vs. control groups). The Gram-positive group also demonstrated significantly higher ADP-induced fibrinogen binding (P = 0.001), as wll as platelet-monocyte complex formation (P = 0.02), compared to the Gram-negative group and had the highest plasma levels of platelet factor 4, β-thromboglobulin and soluble P-selectin. In contrast, thrombin-antithrombin complex and C-reactive protein levels were comparable in both patient groups. In conclusion, common Gram-positive pathogens induce platelet hyperreactivity, which may contribute to a higher risk for vascular complications.

  18. Failure Analysis in Platelet Molded Composite Systems

    NASA Astrophysics Data System (ADS)

    Kravchenko, Sergii G.

    Long-fiber discontinuous composite systems in the form of chopped prepreg tapes provide an advanced, structural grade, molding compound allowing for fabrication of complex three-dimensional components. Understanding of process-structure-property relationship is essential for application of prerpeg platelet molded components, especially because of their possible irregular disordered heterogeneous morphology. Herein, a structure-property relationship was analyzed in the composite systems of many platelets. Regular and irregular morphologies were considered. Platelet-based systems with more ordered morphology possess superior mechanical performance. While regular morphologies allow for a careful inspection of failure mechanisms derived from the morphological characteristics, irregular morphologies are representative of the composite architectures resulting from uncontrolled deposition and molding with chopped prerpegs. Progressive failure analysis (PFA) was used to study the damaged deformation up to ultimate failure in a platelet-based composite system. Computational damage mechanics approaches were utilized to conduct the PFA. The developed computational models granted understanding of how the composite structure details, meaning the platelet geometry and system morphology (geometrical arrangement and orientation distribution of platelets), define the effective mechanical properties of a platelet-molded composite system, its stiffness, strength and variability in properties.

  19. Constitutive modeling of the rheological behavior of platelet suspensions

    NASA Astrophysics Data System (ADS)

    Sommer, Drew E.

    Compression molding of chopped fiber composites is used to manufacture complex 3D geometries with high fiber volume fractions of 50-60% and long, discontinuous fibers and thermoplastic matrices. When prepreg, chopped into platelets, is used as a charge material, the individual platelets remain intact during the molding process and flow relative to one another, as experimental observations show. Heterogeneity of the platelet/resin suspension cannot be considered at the structural scale of molding simulation. Instead, the suspension should be idealized into the homogenized anisotropic and viscous system which obeys the prescribed anisotropic stress-strain rate constitutive relation. The viscosity tensor of the aforementioned constitutive law was analytically evaluated in this work through the representative volume element (RVE) based analysis. An idealized microstructure of platelets was developed to perform such an analysis. The platelets were aligned and arranged in a planar configuration with periodic boundary conditions. Analytic expressions for the effective, anisotropic viscosities were derived by micromechanical analysis for the idealized microstructure of rigid platelets. In this analysis, the load transfer mechanisms and their contribution to the viscosity of the platelet assembly were investigated. The kinematic assumption of linear velocity distributions consistent with the mechanism of shearing rate was adopted. While the platelets were assumed to be rigid, the resin was taken as an incompressible, isotropic fluid which provided for the platelet-to-platelet load transfer. Strain rate and temperature dependence were included by modeling the polymer matrix as a Carreau fluid. Shear strain in the resin was developed due to the relative motion of adjacent platelets. The resin shear strain rate was expressed in terms of the corresponding platelet velocities. Equilibrium of the platelet was used to relate the applied far-field stress to the average strain rate

  20. Regulation of platelet granule exocytosis by S-nitrosylation

    PubMed Central

    Morrell, Craig N.; Matsushita, Kenji; Chiles, Kelly; Scharpf, Robert B.; Yamakuchi, Munekazu; Mason, Rebecca J. A.; Bergmeier, Wolfgang; Mankowski, Joseph L.; Baldwin, William M.; Faraday, Nauder; Lowenstein, Charles J.

    2005-01-01

    Nitric oxide (NO) regulates platelet activation by cGMP-dependent mechanisms and by mechanisms that are not completely defined. Platelet activation includes exocytosis of platelet granules, releasing mediators that regulate interactions between platelets, leukocytes, and endothelial cells. Exocytosis is mediated in part by N-ethylmaleimide-sensitive factor (NSF), an ATPase that disassembles complexes of soluble NSF attachment protein receptors. We now demonstrate that NO inhibits exocytosis of dense granules, lysosomal granules, and α-granules from human platelets by S-nitrosylation of NSF. Platelets lacking endothelial NO synthase show increased rolling on venules, increased thrombosis in arterioles, and increased exocytosis in vivo. Regulation of exocytosis is thus a mechanism by which NO regulates thrombosis. PMID:15738422

  1. Platelet antiheparin activity. The isolation and characterisation of platelet factor 4 released from thrombin-aggregated washed human platelets and its dissociation into subunits and the isolation of membrane-bound antiheparin activity.

    PubMed

    Moore, S; Pepper, D S; Cash, J D

    1975-02-27

    Platelet factor 4 was isolated by gel filtration from the soluble release products of thrombin-aggregated washed human platelets as a proteoglycan-platelet factor 4 complex of molecular weight 358 000, Stokes radius (r-s) of 14.0 nm, sedimentation coefficient (s) of 7.1 S and frictional ratio (f/f-o) of 3.04. The complex was dissociated at high ionic strength (I equals 0.75) and the proteoglycan separated from platelet factor 4 by gel filtration. Platelet factor 4 had a molecular weight of 27 100, r-s of 2.52 nm, s of 2.4 S and f/f-o of 1.26, was insoluble under physiological conditions but readily soluble at pH 3. Under these conditions platelet factor 4 dissociated into four subunits with a molecular weight of 6900, r-s of 1.92 nm, s of 0.8 S, and f/f-o of 1.52. Qualitative N-terminal amino acid analysis showed the presence of glutamic acid or glutamine as the major end group. Platelet factor 4 was compared with protamine sulphate, which has similar biological properties, by electrophoresis at pH 2.2, in which both migrated as single bands but with differing mobility, and by amino acid analysis which showed a more normal distribution of residues than occurred in protamine sulphate. Of the basic amino acids platelet factor 4 (molecular weight 27 100) contained 5.97% arginine, 3.18% histidine, and 12.31% lysine compared to protamine sulphate with 64.2% arginine, 0.6% lysine and no histidine. A partial specific volume (v) of 0.747 was calculated for platelet factor 4 from its amino acid analysis. A membrane fraction with antiheparin activity, an isopycnic density of 1.090-1.110 and r-s of 15-35 nm, was also isolated by sucrose density gradient centrifugation from the ultrasonicated insoluble platelet residue remaining after thrombin-induced aggregation of washed human platelets. Trypsin treatment of the membrane fraction neither solubilised nor destroyed the activity.

  2. Time dependent reduction in platelet aggregation using the multiplate analyser and hirudin blood due to platelet clumping.

    PubMed

    Chapman, Kent; Favaloro, Emmanuel J

    2018-05-01

    The Multiplate is a popular instrument that measures platelet function using whole blood. Potentially considered a point of care instrument, it is also used by hemostasis laboratories. The instrument is usually utilized to assess antiplatelet medication or as a screen of platelet function. According to the manufacturer, testing should be performed within 0.5-3 hours of blood collection, and preferably using manufacturer provided hirudin tubes. We report time-associated reduction in platelet aggregation using the Multiplate and hirudin blood collection tubes, for all the major employed agonists. Blood for Multiplate analysis was collected into manufacturer supplied hirudin tubes, and 21 consecutive samples assessed using manufacturer supplied agonists (ADP, arachidonic acid, TRAP, collagen and ristocetin), at several time-points post-sample collection within the recommended test time period. Blood was also collected into EDTA as a reference method for platelet counts, with samples collected into sodium citrate and hirudin used for comparative counts. All platelet agonists showed a diminution of response with time. Depending on the agonist, the reduction caused 5-20% and 22-47% of responses initially in the normal reference range to fall below the reference range at 120min and 180min, respectively. Considering any agonist, 35% and 67% of initially "normal" responses became 'abnormal' at 120 min and 180 min, respectively. Platelet counts showed generally minimal changes in EDTA blood, but were markedly reduced over time in both citrate and hirudin blood, with up to 40% and 60% reduction, respectively, at 240 min. The presence of platelet clumping (micro-aggregate formation) was also observed in a time dependent manner, especially for hirudin. In conclusion, considering any platelet agonist, around two-thirds of samples can, within the recommended 0.5-3 hour testing window post-blood collection, yield a reduction in platelet aggregation that may lead to a change in

  3. Of von Willebrand factor and platelets.

    PubMed

    Bryckaert, Marijke; Rosa, Jean-Philippe; Denis, Cécile V; Lenting, Peter J

    2015-01-01

    Hemostasis and pathological thrombus formation are dynamic processes that require multiple adhesive receptor-ligand interactions, with blood platelets at the heart of such events. Many studies have contributed to shed light on the importance of von Willebrand factor (VWF) interaction with its platelet receptors, glycoprotein (GP) Ib-IX-V and αIIbβ3 integrin, in promoting primary platelet adhesion and aggregation following vessel injury. This review will recapitulate our current knowledge on the subject from the rheological aspect to the spatio-temporal development of thrombus formation. We will also discuss the signaling events generated by VWF/GPIb-IX-V interaction, leading to platelet activation. Additionally, we will review the growing body of evidence gathered from the recent development of pathological mouse models suggesting that VWF binding to GPIb-IX-V is a promising target in arterial and venous pathological thrombosis. Finally, the pathological aspects of VWF and its impact on platelets will be addressed.

  4. Platelet counting using the Coulter electronic counter.

    PubMed

    Eggleton, M J; Sharp, A A

    1963-03-01

    A method for counting platelets in dilutions of platelet-rich plasm using the Coulter electronic counter is described.(1) The results obtained show that such platelet counts are at least as accurate as the best methods of visual counting. The various technical difficulties encountered are discussed.

  5. Platelet RNA as a circulating biomarker trove for cancer diagnostics.

    PubMed

    Best, M G; Vancura, A; Wurdinger, T

    2017-07-01

    Platelets are multifunctional cell fragments, circulating in blood in high abundance. Platelets assist in thrombus formation, sensing of pathogens entering the blood stream, signaling to immune cells, releasing vascular remodeling factors, and, negatively, enhancing cancer metastasis. Platelets are 'educated' by their environment, including in patients with cancer. Cancer cells appear to initiate intraplatelet signaling, resulting in splicing of platelet pre-mRNAs, and enhance secretion of cytokines. Platelets can induce leukocyte and endothelial cell modeling factors, for example, through adenine nucleotides (ATP), thereby facilitating extravasation of cancer cells. Besides releasing factors, platelets can also sequester RNAs and proteins released by cancer cells. Thus, platelets actively respond to queues from local and systemic conditions, thereby altering their transcriptome and molecular content. Platelets contain a rich repertoire of RNA species, including mRNAs, small non-coding RNAs and circular RNAs; although studies regarding the functionality of the various platelet RNA species require more attention. Recent advances in high-throughput characterization of platelet mRNAs revealed 10 to > 1000 altered mRNAs in platelets in the presence of disease. Hence, platelet RNA appears to be dynamically affected by pathological conditions, thus possibly providing opportunities to use platelet RNA as diagnostic, prognostic, predictive, or monitoring biomarkers. In this review, we cover the literature regarding the platelet RNA families, processing of platelet RNAs, and the potential application of platelet RNA as disease biomarkers. © 2017 International Society on Thrombosis and Haemostasis.

  6. Brief Report: Platelet-Poor Plasma Serotonin in Autism

    ERIC Educational Resources Information Center

    Anderson, George M.; Hertzig, Margaret E.; McBride, P. A.

    2012-01-01

    Possible explanations for the well-replicated platelet hyperserotonemia of autism include an alteration in the platelet's handling of serotonin (5-hydroxyserotonin, 5-HT) or an increased exposure of the platelet to 5-HT. Measurement of platelet-poor plasma (PPP) levels of 5-HT appears to provide the best available index of in vivo exposure of the…

  7. Incomplete inhibition of platelet function as assessed by the platelet function analyzer (PFA-100) identifies a subset of cardiovascular patients with high residual platelet response while on aspirin.

    PubMed

    Crescente, M; Mezzasoma, A M; Del Pinto, M; Palmerini, F; Di Castelnuovo, A; Cerletti, C; De Gaetano, G; Gresele, P

    2011-01-01

    Sixty-six patients with a history of ischemic events (myocardial infarction, unstable angina, or stroke) on chronic aspirin therapy were studied by different platelet function tests: 37 patients had suffered a recurrent event while on aspirin and 29 were without recurrences. Based on results from light transmission aggregometry (LTA) induced by arachidonic acid (AA) and serum TxB(2) both COX-1-dependent methods, only one patient could be identified as aspirin "resistant". However, when methods only partially-dependent on platelet COX-1 activity were considered, the prevalence of aspirin non-responders ranged, according to the different tests, from 0 to 52%. No difference was observed between patients with recurrences and those without. Among patients with recurrent events, those with an incomplete inhibition of platelet function, as assessed by the PFA-100, had significantly higher residual serum TxB(2) (2.4 ± 2.4 ng/mL vs 0.4 ± 0.1 ng/mL, p = 0.03), residual LTA-AA (9.2 ± 10.6% vs 2.0 ± 1.6%, p = 0.008), LTA-Coll (49.3 ± 14.6% vs 10.2 ± 8.3%, p = 0.007) and LTA-ADP (50.9 ± 16.2% vs 34.3 ± 11.0%, p = 0.04). In conclusion, laboratory tests solely exploring the AA-mediated pathway of platelet function, while being the most appropriate to detect the effect of aspirin on its pharmacologic target (platelet COX-1), may fail to reveal the functional interactions between minimal residual TxA(2) and additional stimuli or primers potentially leading to aspirin-insensitive platelet aggregation. High residual platelet response in platelet function tests only partially dependent on COX-1 may reveal a condition of persistent platelet reactivity in a subset of aspirin-treated patients characterizing them as a subgroup at higher vascular risk.

  8. The role of lectins and glycans in platelet clearance

    PubMed Central

    Hoffmeister, Karin M.

    2015-01-01

    Summary In recent years, it has become increasingly apparent that the life span of transfused platelets in circulation is regulated, at least in part, by glycan-lectin mediated mechanisms. There is clear evidence that refrigerated platelets are cleared by glycan-lectin mediated clearance mechanisms. Acute platelet cooling clusters glycoprotein (GP) Ibα receptors bearing uncovered N-acetylglucosamine (GlcNAc), and αMβ2 integrins on hepatic macrophages recognise clustered GlcNAc to rapidly clear these platelets from circulation. With prolonged refrigeration GPIbα clustering bearing uncovered galactose increases, which mediates the removal of long-term refrigerated platelets via hepatic Ashwell-Morell receptors (AMR), originally named as asialoglycoprotein receptors. In contrast, little is known about the molecular mechanisms of transfused room temperature platelet clearance. This review examines the role of glycan-lectin mediated clearance of exogenous, i.e. transfused chilled platelet clearance and briefly addresses the current knowledge of stored platelet function, degradation and its relation to platelet clearance. PMID:21781240

  9. Rupture Forces among Human Blood Platelets at different Degrees of Activation

    PubMed Central

    Nguyen, Thi-Huong; Palankar, Raghavendra; Bui, Van-Chien; Medvedev, Nikolay; Greinacher, Andreas; Delcea, Mihaela

    2016-01-01

    Little is known about mechanics underlying the interaction among platelets during activation and aggregation. Although the strength of a blood thrombus has likely major biological importance, no previous study has measured directly the adhesion forces of single platelet-platelet interaction at different activation states. Here, we filled this void first, by minimizing surface mediated platelet-activation and second, by generating a strong adhesion force between a single platelet and an AFM cantilever, preventing early platelet detachment. We applied our setup to measure rupture forces between two platelets using different platelet activation states, and blockade of platelet receptors. The rupture force was found to increase proportionally to the degree of platelet activation, but reduced with blockade of specific platelet receptors. Quantification of single platelet-platelet interaction provides major perspectives for testing and improving biocompatibility of new materials; quantifying the effect of drugs on platelet function; and assessing the mechanical characteristics of acquired/inherited platelet defects. PMID:27146004

  10. Deletion of Crry and DAF on murine platelets stimulates thrombopoiesis and increases factor H-dependent resistance of peripheral platelets to complement attack.

    PubMed

    Barata, Lidia; Miwa, Takashi; Sato, Sayaka; Kim, David; Mohammed, Imran; Song, Wen-Chao

    2013-03-15

    Complement receptor 1-related gene/protein y (Crry) and decay-accelerating factor (DAF) are two murine membrane C3 complement regulators with overlapping functions. Crry deletion is embryonically lethal whereas DAF-deficient mice are generally healthy. Crry(-/-)DAF(-/-) mice were viable on a C3(-/-) background, but platelets from such mice were rapidly destroyed when transfused into C3-sufficient mice. In this study, we used the cre-lox system to delete platelet Crry in DAF(-/-) mice and studied Crry/DAF-deficient platelet development in vivo. Rather than displaying thrombocytopenia, Pf4-Cre(+)-Crry(flox/flox) mice had normal platelet counts and their peripheral platelets were resistant to complement attack. However, chimera mice generated with Pf4-Cre(+)-Crry(flox/flox) bone marrows showed platelets from C3(-/-) but not C3(+/+) recipients to be sensitive to complement activation, suggesting that circulating platelets in Pf4-Cre(+)-Crry(flox/flox) mice were naturally selected in a complement-sufficient environment. Notably, Pf4-Cre(+)-Crry(flox/flox) mouse platelets became complement susceptible when factor H function was blocked. Examination of Pf4-Cre(+)-Crry(flox/flox) mouse bone marrows revealed exceedingly active thrombopoiesis. Thus, under in vivo conditions, Crry/DAF deficiency on platelets led to abnormal platelet turnover, but peripheral platelet count was compensated for by increased thrombopoiesis. Selective survival of Crry/DAF-deficient platelets aided by factor H protection and compensatory thrombopoiesis demonstrates the cooperation between membrane and fluid phase complement inhibitors and the body's ability to adaptively respond to complement regulator deficiencies.

  11. Platelet counting using the Coulter electronic counter

    PubMed Central

    Eggleton, M. J.; Sharp, A. A.

    1963-01-01

    A method for counting platelets in dilutions of platelet-rich plasm using the Coulter electronic counter is described.1 The results obtained show that such platelet counts are at least as accurate as the best methods of visual counting. The various technical difficulties encountered are discussed. PMID:16811002

  12. Intracellular origin and ultrastructure of platelet-derived microparticles.

    PubMed

    Ponomareva, A A; Nevzorova, T A; Mordakhanova, E R; Andrianova, I A; Rauova, L; Litvinov, R I; Weisel, J W

    2017-08-01

    Essentials Platelet microparticles play a major role in pathologies, including hemostasis and thrombosis. Platelet microparticles have been analyzed and classified based on their ultrastructure. The structure and intracellular origin of microparticles depend on the cell-activating stimulus. Thrombin-treated platelets fall apart and form microparticles that contain cellular organelles. Background Platelet-derived microparticles comprise the major population of circulating blood microparticles that play an important role in hemostasis and thrombosis. Despite numerous studies on the (patho)physiological roles of platelet-derived microparticles, mechanisms of their formation and structural details remain largely unknown. Objectives Here we studied the formation, ultrastructure and composition of platelet-derived microparticles from isolated human platelets, either quiescent or stimulated with one of the following activators: arachidonic acid, ADP, collagen, thrombin or calcium ionophore A23187. Methods Using flow cytometry, transmission and scanning electron microscopy, we analyzed the intracellular origin, structural diversity and size distributions of the subcellular particles released from platelets. Results The structure, dimensions and intracellular origin of microparticles depend on the cell-activating stimulus. The main structural groups include a vesicle surrounded by one thin membrane or multivesicular structures. Thrombin, unlike other stimuli, induced formation of microparticles not only from the platelet plasma membrane and cytoplasm but also from intracellular structures. A fraction of these vesicular particles having an intracellular origin contained organelles, such as mitochondria, glycogen granules and vacuoles. The size of platelet-derived microparticles depended on the nature of the cell-activating stimulus. Conclusion The results obtained provide a structural basis for the qualitative differences of various platelet activators, for specific

  13. EMMPRIN (CD147) is a novel receptor for platelet GPVI and mediates platelet rolling via GPVI-EMMPRIN interaction.

    PubMed

    Seizer, Peter; Borst, Oliver; Langer, Harald F; Bültmann, Andreas; Münch, Götz; Herouy, Yared; Stellos, Konstantinos; Krämer, Björn; Bigalke, Boris; Büchele, Berthold; Bachem, Max G; Vestweber, Dietmar; Simmet, Thomas; Gawaz, Meinrad; May, Andreas E

    2009-04-01

    The Extracellular Matrix Metalloproteinase Inducer (EMMPRIN, CD147, basigin) is an immunoglobulin-like receptor expressed in various cell types. During cellular interactions homotypic EMMPRIN-EMMPRIN interactions are known to induce the synthesis of matrix metalloproteinases. Recently, we have identified EMMPRIN as a novel receptor on platelets. To our knowledge EMMPRIN has not been shown to serve as adhesion receptor, yet. Here we characterise platelet glycoprotein VI (GPVI) as a novel adhesion receptor for EMMPRIN. Human platelets were prestimulated with ADP and perfused over immobilised recombinant EMMPRIN-Fc or Fc-fragments under arterial shear conditions. ADP-stimulated platelets showed significantly enhanced rolling (but not enhanced firm adhesion) on immobilised EMMPRIN-Fc compared to Fc. Pretreatment of platelets with blocking mAbs anti-EMMPRIN or anti-GPVI leads to a significant reduction of rolling platelets on immobilised EMMPRIN-Fc, whereas pretreatment with blocking mAbs anti-p-selectin, anti-alpha4-integrin or anti-GPIIb/IIIa complex (20 microg/ml each) had no effect. Consistently, chinese hamster ovary (CHO) cells stably transfected with GPVI showed enhanced rolling (but not adhesion) on immobilised EMMPRIN-Fc in comparison to non-transfected CHO cells. Similarly, CHO cells stably transfected with EMMPRIN showed enhanced rolling on immobilised GPVI-Fc (or EMMPRIN-Fc) compared to non transfected CHO-cells. Finally, specific binding of EMMPRIN to GPVI was demonstrated by a modified ELISA and surface plasmon resonance technology with a dissociation constant of 88 nM. Platelet GPVI is a novel receptor for EMMPRIN and can mediate platelet rolling via GPVI-EMMPRIN interaction.

  14. Review of in vivo studies of dimethyl sulfoxide cryopreserved platelets.

    PubMed

    Slichter, Sherrill J; Jones, Melinh; Ransom, Janet; Gettinger, Irena; Jones, Mary Kay; Christoffel, Todd; Pellham, Esther; Bailey, S Lawrence; Corson, Jill; Bolgiano, Doug

    2014-10-01

    A literature review was conducted to assess the efficacy and safety of dimethyl sulfoxide (DMSO) cryopreserved platelets for potential military use. In vivo DMSO cryopreserved platelet studies published between 1972 and June of 2013 were reviewed. Assessed were the methods of cryopreservation, posttransfusion platelet responses, prevention or control of bleeding, and adverse events. Using the Department of Defense's preferred 6% DMSO cryopreservation method with centrifugation to remove the DMSO plasma before freezing at -65°C and no postthaw wash, mean radiolabeled platelet recoveries in 32 normal subjects were 33% ± 10% (52% ± 12% of the same subject's fresh platelet recoveries), and survivals were 7.5 ± 1.2 days (89% ± 15% of fresh platelet survivals). Using a variety of methods to freeze autologous platelets from 178 normal subjects, mean radiolabeled platelet recoveries were consistently 39% ± 9%, and survivals, 7.4 ± 1.4 days. More than 3000 cryopreserved platelet transfusions were given to 1334 patients. There were 19 hematology/oncology patient studies, and, in 9, mean 1-hour corrected count increments were 11 100 ± 3600 (range, 5700-15 800) after cryopreserved autologous platelet transfusions. In 5 studies, bleeding times improved after transfusion; in 3, there was either no improvement or a variable response. In 4 studies, there was immediate cessation of bleeding after transfusion; in 3 studies, patients being supported only with cryopreserved platelets had no bleeding. In 1 cardiopulmonary bypass study, cryopreserved platelets resulted in significantly less bleeding vs standard platelets. In 3 trauma studies, cryopreserved platelets were hemostatically effective. No significant adverse events were reported in any study. In summary, cryopreserved platelets have platelet recoveries that are about half of fresh platelets, but survivals are only minimally reduced. The platelets appear hemostatically effective and have no significant adverse events

  15. Analysis of aggregation of platelets in thrombosis

    NASA Astrophysics Data System (ADS)

    Ahuja, Suresh

    Platelets are key players in thrombus formation by first rolling over collagen bound von Willebrand factor followed by formation of a stable interaction with collagen. The first adhered platelets bind additional platelets until the whole injury is sealed off by a platelet aggregate. The coagulation system stabilizes the formed platelet plug by creating a tight fibrin network, and then wound contraction takes place because of morphological changes in platelets. Coagulation takes place by platelet activation and aggregation mainly through fibrinogen polymerization into fibrin fibers. The process includes multiple factors, such as thrombin, plasmin, and local shear-rate which regulate and control the process. Coagulation can be divided into two pathways: the intrinsic pathway and the extrinsic pathway. The intrinsic pathway is initiated by the exposure of a negatively charged. It is able to activate factor XII, using a complex reaction that includes prekallikrein and high-molecular-weight kininogen as cofactors.. Thrombin is the final enzyme that is needed to convert fibrinogen into fibrin. The extrinsic pathway starts with the exposure of tissue factor to the circulating blood, which is the major initiator of coagulation. There are several feedback loops that reinforce the coagulation cascade, resulting in large amounts of thrombin. It is dependent on the presence of pro-coagulant surfaces of cells expressing negatively charged phospholipids--which include phosphatidylserine (PS)--on their outer membrane. PS-bearing surfaces are able to increase the efficiency of the reactions by concentrating and co-localizing coagulation factors.. Aggregation of platelets are analyzed and compared to adhesion of platelet to erythrocyte and to endothelial cells. This abstract is replacing MAR16-2015-020003.

  16. Platelet gel: a new therapeutic tool with great potential

    PubMed Central

    Piccin, Andrea; Di Pierro, Angela M.; Canzian, Lucia; Primerano, Marco; Corvetta, Daisy; Negri, Giovanni; Mazzoleni, Guido; Gastl, Günther; Steurer, Michael; Gentilini, Ivo; Eisendle, Klaus; Fontanella, Fabrizio

    2017-01-01

    Chronic wounds, such as diabetic foot ulcers, represent a serious clinical problem for patients and clinicians. Management of these wounds has a strong economic impact worldwide. Complications resulting from injuries are a frequent cause of morbidity and mortality. Chronic wounds lead to infections, painful dressings and prolonged hospitalisation. This results in poor patient Quality of Life and in high healthcare costs. Platelet concentrates (PC) are defined as autologous or allogeneic platelet derivatives with a platelet concentration higher than baseline. PC are widely used in different areas of Regenerative Medicine in order to enhance wound healing processes; they include platelet-rich plasma (PRP), platelet gel (PG), platelet-rich fibrin (PRF), serum eye drops (E-S), and PRP eye drops (E-PRP). This review highlights the use of platelet-rich plasma (PRP) and platelet gel (PG) preparation for clinical use. PMID:27483482

  17. Second-generation Platelet Concentrate (Platelet-rich Fibrin) as a Scaffold in Regenerative Endodontics: A Case Series.

    PubMed

    Bakhtiar, Hengameh; Esmaeili, Shahram; Fakhr Tabatabayi, Setareh; Ellini, Mohammad Reza; Nekoofar, Mohammad Hossein; Dummer, Paul M H

    2017-03-01

    The purpose of this case series was to report the clinical and radiographic results of a pulp regenerative procedure using platelet-rich fibrin (PRF), a second-generation platelet concentrate, in immature teeth with necrotic pulps. Root canal revascularization using PRF was performed on 4 immature teeth with necrotic pulps. After access cavity preparation, the root canals were irrigated with low concentration sodium hypochlorite solution (1.5% sodium hypochlorite [20 mL/canal, 5 minutes]) and then irrigated with saline (20 mL/canal, 5 minutes). Equal proportions (167 mg) of ciprofloxacin, metronidazole, and cefaclor were mixed and diluted to a final concentration of 1 g/mL. Finally, the canal was sealed with 3-4 mm of a temporary restorative material, and patients were dismissed for 2 to 3 weeks. At the second appointment, 9 mL of the patient's whole blood was obtained and centrifuged to prepare a PRF clot. Canals were irrigated with 17% EDTA, and a sharp spreader was inserted beyond the apex. Then, the PRF clot was placed inside the root canals, and Biodentine (Septodont, Saint-Maur, France) was placed directly over the PRF. The teeth were restored permanently with glass ionomer cement and composite resin. Clinical examinations revealed that all cases were asymptomatic at the recall appointments at 1, 3, 6, 12, and 18 months. Radiographs revealed resolution of the periapical lesions, further root development, and apical closure in all cases. On the basis of the short-term results up to 12 months, PRF clots acted as successful scaffolds for the regeneration of pulpal contents in immature teeth with necrotic pulps. Copyright © 2016 American Association of Endodontists. All rights reserved.

  18. The Relationship of Mean Platelet Volume/Platelet Distribution Width and Duodenal Ulcer Perforation.

    PubMed

    Fan, Zhe; Zhuang, Chengjun

    2017-03-01

    Duodenal ulcer perforation (DUP) is a severe acute abdominal disease. Mean platelet volume (MPV) and platelet distribution width (PDW) are two platelet parameters, participating in many inflammatory processes. This study aims to investigate the relation of MPV/PDW and DUP. A total of 165 patients were studied retrospectively, including 21 females and 144 males. The study included two groups: 87 normal patients (control group) and 78 duodenal ulcer perforation patients (DUP group). Routine blood parameters were collected for analysis including white blood cell count (WBC), neutrophil ratio (NR), platelet count (PLT), MPV and PDW. Receiver operating curve (ROC) analysis was applied to evaluate the parameters' sensitivity. No significant differences were observed between the control group and DUP group in age and gender. WBC, NR and PDW were significantly increased in the DUP group ( P <0.001, respectively); PLT and MPV were significantly decreased in the DUP group ( P <0.001, respectively) compared to controls. MPV had the high sensitivity. Our results suggested a potential association between MPV/PDW and disease activity in DUP patients, and high sensitivity of MPV. © 2017 by the Association of Clinical Scientists, Inc.

  19. Treatment of platelets with riboflavin and ultraviolet light mediates complement activation and suppresses monocyte interleukin-12 production in whole blood.

    PubMed

    Loh, Y S; Dean, M M; Johnson, L; Marks, D C

    2015-11-01

    Pathogen inactivation (PI) and storage may alter the immunomodulatory capacity of platelets (PLTs). The aim of this study was to examine the effect of PI (Riboflavin and ultraviolet light treatment) and storage on the capacity of PLTs to induce cytokine responses in recipient inflammatory cells. A pool and split design was used to prepare untreated and PI-treated buffy coat-derived platelet concentrates (PCs). Samples were taken on days 2 and 7 postcollection and incubated with ABO/RhD-matched fresh whole blood for 6 h with or without lipopolysaccharide (LPS). The intracellular production of IP-10, MCP-1, MIP-1α, IL-8, IL-6, IL-10, IL-12, TNF-α and MIP-1β in monocytes and neutrophils was assessed using flow cytometry. Complement proteins in PLT supernatants were measured using a cytometric bead array. PLTs and PLT supernatant (both untreated and PI-treated) resulted in modulation of intracellular MIP-1β and IL-12 production in monocytes. Compared to untreated PLTs, PI-treated PLTs resulted in significantly lower LPS-induced monocyte IL-12 production (day 7). The concentration of C3a and C5a (and their desArg forms) was significantly increased in PLT supernatants following PI. PI results in decreased LPS-induced monocyte IL-12 production and increased complement activation. The association between platelet-induced complement activation and IL-12 production warrants further investigation. © 2015 International Society of Blood Transfusion.

  20. Regenerative medicine for the treatment of Teno-desmic injuries of the equine. A series of 150 horses treated with platelet-derived growth factors.

    PubMed

    Scala, Marco; Lenarduzzi, Silvia; Spagnolo, Francesco; Trapasso, Maria; Ottonello, Chiara; Muraglia, Anita; Barla, Annalisa; Squillario, Margherita; Strada, Paolo

    2014-01-01

    The aim of the present study was to evaluate the safety and the clinical outcome of platelet-rich plasma for the treatment of teno-desmic injures in competition horses. From January 2009 to December 2011, 150 sport horses suffering from teno-desmic injuries were treated with no-gelled platelet-concentrate. No horse showed any major adverse reaction as a result of the procedure. Full healing was obtained for 81% of the horses. Twelve percent had clinical improvement and only 7% a failure. Eight percent of cases of relapse were observed. No statistically significant correlation existed between clinical outcome and the area of the lesion. A statistically significant correlation existed between the clinical outcome and the age of the horse. Treatment with platelet-derived growth factors leads to the formation of a tendon with normal morphology and functionality, which translate in the resumption of the agonistic activity for the horses we treated. Copyright © 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  1. Use of a Cyclooxygenase-2 Inhibitor Does Not Inhibit Platelet Activation or Growth Factor Release From Platelet-Rich Plasma.

    PubMed

    Ludwig, Hilary C; Birdwhistell, Kate E; Brainard, Benjamin M; Franklin, Samuel P

    2017-12-01

    It remains unestablished whether use of cyclooxygenase (COX)-2 inhibitors impairs platelet activation and anabolic growth factor release from platelets in platelet-rich plasma (PRP). The purpose of this study was to assess the effects of a COX-2 inhibitor on platelet activation and anabolic growth factor release from canine PRP when using a clinically applicable PRP activator and to determine whether a 3-day washout would be sufficient to abrogate any COX-2 inhibitor-related impairment on platelet function. Controlled laboratory study. Ten healthy dogs underwent blood collection and PRP preparation. Dogs were then administered a COX-2 inhibitor for 7 days, after which PRP preparation was repeated. The COX-2 inhibitor was continued for 4 more days and PRP preparation performed a third time, 3 days after discontinuation of the COX-2 inhibitor. Immediately after PRP preparation, the PRP was divided into 4 aliquots: 2 unactivated and 2 activated using human γ-thrombin (HGT). One activated and 1 unactivated sample were assessed using flow cytometry for platelet expression of CD62P and platelet-bound fibrinogen using the canine activated platelet-1 (CAP1) antibody. The 2 remaining samples were centrifuged and the supernatant assayed for transforming growth factor-β1 (TGF-β1), platelet-derived growth factor-BB (PDGF-BB), and thromboxane B2 (TXB2) concentrations. Differences in platelet activation and TGF-β1, PDGF-BB, and TXB2 concentrations over the 3 study weeks were evaluated using a 1-way repeated-measures ANOVA, and comparisons between activated and unactivated samples within a study week were assessed with paired t tests. There were no statistically significant ( P > .05) effects of the COX-2 inhibitor on percentage of platelets positive for CD62P or CAP1 or on concentrations of TGF-β1, PDGF-BB, or TXB2. All unactivated samples had low levels of activation or growth factor concentrations and significantly ( P < .05) greater activation and growth factor

  2. Platelet Immunology in China: Research and Clinical Applications.

    PubMed

    Wu, Guoguang; Zhou, Yan; Li, Lilan; Zhong, Zhoulin; Li, Hengchong; Li, Haiyan; Yu, Mei; Shen, Weidong; Ni, Heyu

    2017-04-01

    Immunization against human platelet alloantigens (HPAs) is associated with a number of clinical complications. The detection and identification of clinically relevant platelet antibodies are important for the diagnosis and management of patients affected with immune-mediated thrombocytopenias. Human platelet alloantigen frequencies and the characteristics of antiplatelet antibodies vary widely between ethnic groups. Since 2008, the importance of platelet immunology in the field of transfusion medicine has gained greater recognition by clinical laboratories in China. Laboratories in China have established and improved methods for platelet antibody detection and HPA genotyping techniques, which are used for the diagnosis of alloimmune platelet disorders in clinic and research environments. Research has revealed the frequencies of HPA alleles in different Chinese ethnic groups and compared the differences in HPA gene frequencies between the Chinese Han and other ethnic groups of the world. Production of anti-CD36 isoantibodies is an important risk factor for immune-mediated thrombocytopenia in the Chinese population. Advances in research and clinical application of platelet immunology have significantly improved the clinical diagnosis, treatment including transfusion support, and prevention of alloimmune platelet disorders in the Chinese population. Copyright © 2017. Published by Elsevier Inc.

  3. An Evaluation of the Accuracy of the Subtraction Method Used for Determining Platelet Counts in Advanced Platelet-Rich Fibrin and Concentrated Growth Factor Preparations

    PubMed Central

    Watanabe, Taisuke; Isobe, Kazushige; Suzuki, Taiji; Kawabata, Hideo; Nakamura, Masayuki; Tsukioka, Tsuneyuki; Okudera, Toshimitsu; Okudera, Hajime; Uematsu, Kohya; Okuda, Kazuhiro; Nakata, Koh; Kawase, Tomoyuki

    2017-01-01

    Platelet concentrates should be quality-assured of purity and identity prior to clinical use. Unlike for the liquid form of platelet-rich plasma, platelet counts cannot be directly determined in solid fibrin clots and are instead calculated by subtracting the counts in other liquid or semi-clotted fractions from those in whole blood samples. Having long suspected the validity of this method, we herein examined the possible loss of platelets in the preparation process. Blood samples collected from healthy male donors were immediately centrifuged for advanced platelet-rich fibrin (A-PRF) and concentrated growth factors (CGF) according to recommended centrifugal protocols. Blood cells in liquid and semi-clotted fractions were directly counted. Platelets aggregated on clot surfaces were observed by scanning electron microscopy. A higher centrifugal force increased the numbers of platelets and platelet aggregates in the liquid red blood cell fraction and the semi-clotted red thrombus in the presence and absence of the anticoagulant, respectively. Nevertheless, the calculated platelet counts in A-PRF/CGF preparations were much higher than expected, rendering the currently accepted subtraction method inaccurate for determining platelet counts in fibrin clots. To ensure the quality of solid types of platelet concentrates chairside in a timely manner, a simple and accurate platelet-counting method should be developed immediately. PMID:29563413

  4. Red blood cell transfusion and increased length of storage are not associated with deep vein thrombosis in medical and surgical critically ill patients: a prospective observational cohort study

    PubMed Central

    2011-01-01

    Introduction With prolonged storage times, cell membranes of red blood cells (RBCs) undergo morphologic and biochemical changes, termed 'RBC storage lesions'. Storage lesions may promote inflammation and thrombophilia when transfused. In trauma patients, RBC transfusion was an independent risk factor for deep vein thrombosis (DVT), specifically when RBC units were stored > 21 days or when 5 or more units were transfused. The objective of this study was to determine if RBC transfusions or RBC storage age predicts incident DVT in medical or surgical intensive care unit (ICU) patients. Methods Using a database which prospectively enrolled 261 patients over the course of 1 year with an ICU stay of at least 3 days, we analyzed DVT and RBC transfusions using Cox proportional hazards regression. Transfusions were analyzed with 4 thresholds, and storage age using 3 thresholds. DVTs were identified by twice-weekly proximal leg ultrasounds. Multivariable analyses were adjusted for 4 significant DVT predictors in this population (venous thrombosis history, chronic dialysis, platelet transfusion and inotropes). Results Of 261 patients, 126 (48.3%) had at least 1 RBC transfusion; 46.8% of those transfused had ≥ 5 units in ICU. Patients receiving RBCs were older (68.8 vs 64.1 years), more likely to be female (47.0 vs 30.7), sicker (APACHEII 26.8 vs 24.4), and more likely to be surgical (21.4 vs 8.9) (P < 0.05). The total number of RBCs per patient was 1-64, mean was 6.3 (SD 7.5), median was 4 (IQR 2,8). In univariate analyses, there was no association between DVT and RBC exposure (1 day earlier, 3 days earlier, 7 days earlier, or ever) or RBC storage (≤ 7 or > 7 days, ≤ 14 or > 14 days, ≤ 21 or > 21 days). Among patients transfused, no multivariable analyses showed that RBC transfusion or storage age predicted DVT. Trends were counter to the hypothesis (e.g., RBC storage for ≤ 7 days suggested a higher DVT risk compared to > 7 days (HR 5.3; 95% CI 1

  5. Scalable Functionalized Graphene Nano-platelets as Tunable Cathodes for High-performance Lithium Rechargeable Batteries

    PubMed Central

    Kim, Haegyeom; Lim, Hee-Dae; Kim, Sung-Wook; Hong, Jihyun; Seo, Dong-Hwa; Kim, Dae-chul; Jeon, Seokwoo; Park, Sungjin; Kang, Kisuk

    2013-01-01

    High-performance and cost-effective rechargeable batteries are key to the success of electric vehicles and large-scale energy storage systems. Extensive research has focused on the development of (i) new high-energy electrodes that can store more lithium or (ii) high-power nano-structured electrodes hybridized with carbonaceous materials. However, the current status of lithium batteries based on redox reactions of heavy transition metals still remains far below the demands required for the proposed applications. Herein, we present a novel approach using tunable functional groups on graphene nano-platelets as redox centers. The electrode can deliver high capacity of ~250 mAh g−1, power of ~20 kW kg−1 in an acceptable cathode voltage range, and provide excellent cyclability up to thousands of repeated charge/discharge cycles. The simple, mass-scalable synthetic route for the functionalized graphene nano-platelets proposed in this work suggests that the graphene cathode can be a promising new class of electrode. PMID:23514953

  6. Swarm Intelligence-Enhanced Detection of Non-Small-Cell Lung Cancer Using Tumor-Educated Platelets.

    PubMed

    Best, Myron G; Sol, Nik; In 't Veld, Sjors G J G; Vancura, Adrienne; Muller, Mirte; Niemeijer, Anna-Larissa N; Fejes, Aniko V; Tjon Kon Fat, Lee-Ann; Huis In 't Veld, Anna E; Leurs, Cyra; Le Large, Tessa Y; Meijer, Laura L; Kooi, Irsan E; Rustenburg, François; Schellen, Pepijn; Verschueren, Heleen; Post, Edward; Wedekind, Laurine E; Bracht, Jillian; Esenkbrink, Michelle; Wils, Leon; Favaro, Francesca; Schoonhoven, Jilian D; Tannous, Jihane; Meijers-Heijboer, Hanne; Kazemier, Geert; Giovannetti, Elisa; Reijneveld, Jaap C; Idema, Sander; Killestein, Joep; Heger, Michal; de Jager, Saskia C; Urbanus, Rolf T; Hoefer, Imo E; Pasterkamp, Gerard; Mannhalter, Christine; Gomez-Arroyo, Jose; Bogaard, Harm-Jan; Noske, David P; Vandertop, W Peter; van den Broek, Daan; Ylstra, Bauke; Nilsson, R Jonas A; Wesseling, Pieter; Karachaliou, Niki; Rosell, Rafael; Lee-Lewandrowski, Elizabeth; Lewandrowski, Kent B; Tannous, Bakhos A; de Langen, Adrianus J; Smit, Egbert F; van den Heuvel, Michel M; Wurdinger, Thomas

    2017-08-14

    Blood-based liquid biopsies, including tumor-educated blood platelets (TEPs), have emerged as promising biomarker sources for non-invasive detection of cancer. Here we demonstrate that particle-swarm optimization (PSO)-enhanced algorithms enable efficient selection of RNA biomarker panels from platelet RNA-sequencing libraries (n = 779). This resulted in accurate TEP-based detection of early- and late-stage non-small-cell lung cancer (n = 518 late-stage validation cohort, accuracy, 88%; AUC, 0.94; 95% CI, 0.92-0.96; p < 0.001; n = 106 early-stage validation cohort, accuracy, 81%; AUC, 0.89; 95% CI, 0.83-0.95; p < 0.001), independent of age of the individuals, smoking habits, whole-blood storage time, and various inflammatory conditions. PSO enabled selection of gene panels to diagnose cancer from TEPs, suggesting that swarm intelligence may also benefit the optimization of diagnostics readout of other liquid biopsy biosources. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  7. Interaction of human platelets with laminin and identification of the 67 kDa laminin receptor on platelets.

    PubMed Central

    Tandon, N N; Holland, E A; Kralisz, U; Kleinman, H K; Robey, F A; Jamieson, G A

    1991-01-01

    A microtitre adhesion assay has been developed to define parameters affecting the adherence of washed platelets to laminin. Adherence was optimally supported by Mg2+ and was inhibited by Ca2+ and by anti-laminin Fab fragments, but significant adhesion (75-90% of control) was found both in heparinized plasma containing physiological levels of bivalent cations and in plasma anti-coagulated with EGTA. Adherence was unaffected by platelet activation with ADP but was decreased by 50% by treatment with alpha-thrombin (1 unit/ml, 5 min). Adherence was unaffected by monospecific polyclonal antibodies to glycoprotein (GP) Ib and GPIV, and was normal with platelets from two patients with Glanzmann's thrombasthaenia, indicating that GPIb, the GPIIb/IIIa complex and GPIV are not involved in platelet-laminin interaction. Affinity chromatography of Triton-solubilized membranes on laminin-Sepharose followed by elution with 0.2 M-glycine/HCl (pH 2.85) identified a major band with a molecular mass of 67 kDa in the reduced and of 53 kDa in the unreduced form. This protein gave a positive reaction on Western blotting with a monospecific polyclonal antibody raised against the high-affinity laminin receptor isolated from human breast carcinoma tissue. The adhesion of platelets to laminin was inhibited by two monoclonal IgM antibodies specific to the LR-1 domain of the 67 kDa receptor. The binding protein was surface-oriented, as shown by flow cytofluorimetry and by the fact that it could be iodinated in intact platelets, but it was not labelled by the periodate-borotritide procedure, suggesting that it did not contain terminal sialic acid. The laminin-derived peptides Tyr-Ile-Gly-Ser-Arg and Cys-Asp-Pro-Gly-Tyr-Ile-Gly-Ser-Arg-NH2, which constitute a complementary binding domain in laminin for the 67 kDa receptor, themselves supported platelet adhesion, bound to the receptor and inhibited the adhesion of platelets to laminin. In addition, Fab fragments of anti

  8. Extramitochondrial energy production in platelets.

    PubMed

    Ravera, Silvia; Signorello, Maria Grazia; Bartolucci, Martina; Ferrando, Sara; Manni, Lucia; Caicci, Federico; Calzia, Daniela; Panfoli, Isabella; Morelli, Alessandro; Leoncini, Giuliana

    2018-05-01

    Energy demand in human platelets is very high, to carry out their functions. As for most human cells, the aerobic metabolism represents the primary energy source in platelets, even though mitochondria are negligibly represented. Following the hypothesis that other structures could be involved in chemical energy production, in this work, we have investigated the functional expression of an extramitochondrial aerobic metabolism in platelets. Oximetric and luminometric analyses showed that platelets consume large amounts of oxygen and produce ATP in the presence of common respiring substrates, such as pyruvate + malate or succinate, although morphological electron microscopy analysis showed that these contain few mitochondria. However, evaluation of the anaerobic glycolytic metabolism showed that only 13% of consumed glucose was converted to lactate. Interestingly, the highest OXPHOS activity was observed in the presence of NADH, not a readily permeant respiring substrate for mitochondria. Also, oxygen consumption and ATP synthesis fuelled by NADH were not affected by atractyloside, an inhibitor of the adenine nucleotide translocase, suggesting that these processes may not be ascribed to mitochondria. Functional data were confirmed by immunofluorescence microscopy and Western blot analyses, showing a consistent expression of the β subunit of F 1 F o -ATP synthase and COXII, a subunit of Complex IV, but a low signal of translocase of the inner mitochondrial membrane (a protein not involved in OXPHOS metabolism). Interestingly, the NADH-stimulated oxygen consumption and ATP synthesis increased in the presence of the physiological platelets agonists, thrombin or collagen. Data suggest that in platelets, aerobic energy production is mainly driven by an extramitochondrial OXPHOS machinery, originated inside the megakaryocyte, and that this metabolism plays a pivotal role in platelet activation. This work represents a further example of the existence of an

  9. Platelets and their chemokines in atherosclerosis—clinical applications

    PubMed Central

    von Hundelshausen, Philipp; Schmitt, Martin M. N.

    2014-01-01

    The concept of platelets as important players in the process of atherogenesis has become increasingly accepted due to accumulating experimental and clinical evidence. Despite the progress in understanding the molecular details of atherosclerosis, particularly by using animal models, the inflammatory and thrombotic roles of activated platelet s especially in the human system remain difficult to dissect, as often only the complications of atherosclerosis, i.e., stroke and myocardial infarction are definable but not the plaque burden. Platelet indices including platelet count and mean platelet volume (MPV) and soluble mediators released by activated platelets are associated with atherosclerosis. The chemokine CXCL4 has multiple atherogenic activities, e.g., altering the differentiation of T cells and macrophages by inhibiting neutrophil and monocyte apoptosis and by increasing the uptake of oxLDL and synergizing with CCL5. CCL5 is released and deposited on endothelium by activated platelets thereby triggering atherogenic monocyte recruitment, which can be attenuated by blocking the corresponding chemokine receptor CCR5. Atheroprotective and plaque stabilizing properties are attributed to CXCL12, which plays an important role in regenerative processes by attracting progenitor cells. Its release from luminal attached platelets accelerates endothelial healing after injury. Platelet surface molecules GPIIb/IIIa, GP1bα, P-selectin, JAM-A and the CD40/CD40L dyade are crucially involved in the interaction with endothelial cells, leukocytes and matrix molecules affecting atherogenesis. Beyond the effects on the arterial inflammatory infiltrate, platelets affect cholesterol metabolism by binding, modifying and endocytosing LDL particles via their scavenger receptors and contribute to the formation of lipid laden macrophages. Current medical therapies for the prevention of atherosclerotic therapies enable the elucidation of mechanisms linking platelets to inflammation and

  10. Platelets and Infections – Complex Interactions with Bacteria

    PubMed Central

    Hamzeh-Cognasse, Hind; Damien, Pauline; Chabert, Adrien; Pozzetto, Bruno; Cognasse, Fabrice; Garraud, Olivier

    2015-01-01

    Platelets can be considered sentinels of vascular system due to their high number in the circulation and to the range of functional immunoreceptors they express. Platelets express a wide range of potential bacterial receptors, including complement receptors, FcγRII, Toll-like receptors but also integrins conventionally described in the hemostatic response, such as GPIIb–IIIa or GPIb. Bacteria bind these receptors either directly, or indirectly via fibrinogen, fibronectin, the first complement C1q, the von Willebrand Factor, etc. The fate of platelet-bound bacteria is questioned. Several studies reported the ability of activated platelets to internalize bacteria such as Staphylococcus aureus or Porphyromonas gingivalis, though there is no clue on what happens thereafter. Are they sheltered from the immune system in the cytoplasm of platelets or are they lysed? Indeed, while the presence of phagolysosome has not been demonstrated in platelets, they contain antimicrobial peptides that were shown to be efficient on S. aureus. Besides, the fact that bacteria can bind to platelets via receptors involved in hemostasis suggests that they may induce aggregation; this has indeed been described for Streptococcus sanguinis, S. epidermidis, or C. pneumoniae. On the other hand, platelets are able to display an inflammatory response to an infectious triggering. We, and others, have shown that platelet release soluble immunomodulatory factors upon stimulation by bacterial components. Moreover, interactions between bacteria and platelets are not limited to only these two partners. Indeed, platelets are also essential for the formation of neutrophil extracellular traps by neutrophils, resulting in bacterial clearance by trapping bacteria and concentrating antibacterial factors but in enhancing thrombosis. In conclusion, the platelet–bacteria interplay is a complex game; its fine analysis is complicated by the fact that the inflammatory component adds to the aggregation response

  11. Platelets: No longer bystanders in liver disease

    PubMed Central

    Adams, David H.; Watson, Steve P.; Lalor, Patricia F.

    2016-01-01

    Growing lines of evidence recognize that platelets play a central role in liver homeostasis and pathobiology. Platelets have important roles at every stage during the continuum of liver injury and healing. These cells contribute to the initiation of liver inflammation by promoting leukocyte recruitment through sinusoidal endothelium. They can activate effector cells, thus amplifying liver damage, and by modifying the hepatic cellular and cytokine milieu drive both hepatoprotective and hepatotoxic processes. Conclusion: In this review we summarize how platelets drive such pleiotropic actions and attempt to reconcile the paradox of platelets being both deleterious and beneficial to liver function; with increasingly novel methods of manipulating platelet function at our disposal, we highlight avenues for future therapeutic intervention in liver disease. (Hepatology 2016;64:1774‐1784) PMID:26934463

  12. Evaluation of three methods of platelet labelling.

    PubMed

    Mortelmans, L; Verbruggen, A; De Roo, M; Vermylen, J

    1986-07-01

    The study of the kinetics of labelled platelets makes sense only when the platelets preserve their viability after separation and labelling. The separation and labelling procedures described in the manual of two producers of 111In-oxinate (Amersham, Mallinckrodt) have been evaluated by in vitro aggregation tests. The method of Mallinckrodt diminished the aggregation capacities of the thrombocytes. The labelled platelets with normal in vitro aggregation response (Amersham) were tested in vivo in 11 patients who underwent peripheral bypass surgery. The platelet half-life and the platelet accumulation on bypass grafts were checked one week post-operatively. Because of the poor in vivo response of both methods (exponential half-life curve and bad graft visualization), a third method was optimized in our laboratory with good in vitro and in vivo results in 12 patients.

  13. Platelet-rich plasma stimulated by pulse electric fields: Platelet activation, procoagulant markers, growth factor release and cell proliferation.

    PubMed

    Frelinger, A L; Torres, A S; Caiafa, A; Morton, C A; Berny-Lang, M A; Gerrits, A J; Carmichael, S L; Neculaes, V B; Michelson, A D

    2016-01-01

    Therapeutic use of activated platelet-rich plasma (PRP) has been explored for wound healing, hemostasis and antimicrobial wound applications. Pulse electric field (PEF) stimulation may provide more consistent platelet activation and avoid complications associated with the addition of bovine thrombin, the current state of the art ex vivo activator of therapeutic PRP. The aim of this study was to compare the ability of PEF, bovine thrombin and thrombin receptor activating peptide (TRAP) to activate human PRP, release growth factors and induce cell proliferation in vitro. Human PRP was prepared in the Harvest SmartPreP2 System and treated with vehicle, PEF, bovine thrombin, TRAP or Triton X-100. Platelet activation and procoagulant markers and microparticle generation were measured by flow cytometry. Released growth factors were measured by ELISA. The releasates were tested for their ability to stimulate proliferation of human epithelial cells in culture. PEF produced more platelet-derived microparticles, P-selectin-positive particles and procoagulant annexin V-positive particles than bovine thrombin or TRAP. These differences were associated with higher levels of released epidermal growth factor after PEF than after bovine thrombin or TRAP but similar levels of platelet-derived, vascular-endothelial, and basic fibroblast growth factors, and platelet factor 4. Supernatant from PEF-treated platelets significantly increased cell proliferation compared to plasma. In conclusion, PEF treatment of fresh PRP results in generation of microparticles, exposure of prothrombotic platelet surfaces, differential release of growth factors compared to bovine thrombin and TRAP and significant cell proliferation. These results, together with PEF's inherent advantages, suggest that PEF may be a superior alternative to bovine thrombin activation of PRP for therapeutic applications.

  14. HMGB1 binds to activated platelets via the receptor for advanced glycation end products and is present in platelet rich human coronary artery thrombi.

    PubMed

    Ahrens, Ingo; Chen, Yung-Chih; Topcic, Danijal; Bode, Michael; Haenel, David; Hagemeyer, Christoph E; Seeba, Hannah; Duerschmied, Daniel; Bassler, Nicole; Jandeleit-Dahm, Karin A; Sweet, Matthew J; Agrotis, Alex; Bobik, Alex; Peter, Karlheinz

    2015-11-01

    High mobility group box 1 (HMGB1) acts as both a nuclear protein that regulates gene expression, as well as a pro-inflammatory alarmin that is released from necrotic or activated cells. Recently, HMGB1-expression in human atherosclerotic plaques was identified. Therapeutic blockade of HMGB1 reduced the development of diet-induced atherosclerosis in ApoE knockout mice. Thus, we hypothesised an interaction between HMGB1 and activated platelets. Binding of recombinant HMGB1 to platelets was assessed by flow cytometry. HMGB1 bound to thrombin-activated human platelets (MFI 2.49 vs 25.01, p=0.0079). Blood from wild-type, TLR4 and RAGE knockout mice was used to determine potential HMGB1 receptors on platelets. HMGB1 bound to platelets from wild type C57Bl6 (MFI 2.64 vs 20.3, p< 0.05), and TLR4-/- mice (MFI 2.11 vs 25.65, p< 0.05) but failed to show binding to platelets from RAGE-/- mice (p > 0.05). RAGE expression on human platelets was detected by RT-PCR with mRNA extracted from highly purified platelets and confirmed by Western blot and immunofluorescence microscopy. Platelet activation increased RAGE surface expression (MFI 4.85 vs 6.74, p< 0.05). Expression of HMGB1 in human coronary artery thrombi was demonstrated by immunohistochemistry and revealed high expression levels. Platelets bind HMGB1 upon thrombin-induced activation. Platelet specific expression of RAGE could be detected at the mRNA and protein level and is involved in the binding of HMGB1. Furthermore, platelet activation up-regulates platelet surface expression of RAGE. HMGB1 is highly expressed in platelet-rich human coronary artery thrombi pointing towards a central role for HMGB1 in atherothrombosis, thereby suggesting the possibility of platelet targeted anti-inflammatory therapies for atherothrombosis.

  15. Lymphocyte-platelet crosstalk in Graves' disease.

    PubMed

    Kuznik, Boris I; Vitkovsky, Yuri A; Gvozdeva, Olga V; Solpov, Alexey V; Magen, Eli

    2014-03-01

    Platelets can modulate lymphocytes' role in the pathophysiology of thyroid autoimmune diseases. The present study was performed to clarify the status of platelet-lymphocyte subpopulations aggregation in circulating blood in patients with Graves' disease (GD). One hundred and fifty patients with GD (GD group) and 45 hyperthyroid patients with toxic multinodular goiter (TMG group) were recruited in the study. Control group consisted 150 healthy subjects. Immunophenotyping of lymphocytes was performed by flow cytometry. Detection of lymphocyte-platelet aggregates (LPAs) was done using light microscope after Ficoll-gradient centrifugation. The group of GD patients exhibited reduced CD8 lymphocyte and higher CD19 cell counts compared with TMG group and healthy controls. A greater number of activated CD3, HLA-DR+ lymphocytes were observed in GD than in TMG group and control group. GD group was characterized by lower blood platelet count (232 ± 89 × 10 cells/µL) than TMG group (251 ± 97 × 10 cells/µL; P < 0.05) and control group (262 ± 95 × 10 cells/µL; P < 0.05). In GD group, more platelet-bound lymphocytes (332 ± 91 /µL) were found than that in TMG group (116 ± 67/µL, P < 0.005) and control group (104 ± 58 /µL; P < 0.001). GD is associated with higher levels of activated lymphocytes and lymphocyte-platelet aggregates.

  16. Mechanobiology of Platelets: Techniques to Study the Role of Fluid Flow and Platelet Retraction Forces at the Micro- and Nano-Scale

    PubMed Central

    Feghhi, Shirin; Sniadecki, Nathan J.

    2011-01-01

    Coagulation involves a complex set of events that are important in maintaining hemostasis. Biochemical interactions are classically known to regulate the hemostatic process, but recent evidence has revealed that mechanical interactions between platelets and their surroundings can also play a substantial role. Investigations into platelet mechanobiology have been challenging however, due to the small dimensions of platelets and their glycoprotein receptors. Platelet researchers have recently turned to microfabricated devices to control these physical, nanometer-scale interactions with a higher degree of precision. These approaches have enabled exciting, new insights into the molecular and biomechanical factors that affect platelets in clot formation. In this review, we highlight the new tools used to understand platelet mechanobiology and the roles of adhesion, shear flow, and retraction forces in clot formation. PMID:22272117

  17. Platelet kinetics and biodistribution in canine endotoxemia

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sostman, H.D.; Zoghbi, S.S.; Smith, G.J.

    Kinetics and magnitudes of changes in indium-labeled platelet biodistribution were studied in dogs given E. coli endotoxin. Marked, reversible, dose-dependent shifts of platelets from blood to lung and apparently irreversible shifts to liver were demonstrated. These were contemporaneous with alterations in blood gases and in pulmonary and systemic hemodynamics. Morphologic studies revealed atelectasis, sequestration of leukocytes and platelets in the lungs, and mild interstitial pulmonary edema. This study provides in vivo quantification of labeled platelet response to a specific stimulus, and illustrates a method that could be applied to more extensive study of blood element participation in acute lung injury.

  18. Potentiation by adrenaline of human platelet activation and the inhibition by the alpha-adrenergic antagonist nicergoline of platelet adhesion, secretion and aggregation.

    PubMed

    Lanza, F; Cazenave, J P; Beretz, A; Sutter-Bay, A; Kretz, J G; Kieny, R

    1986-08-01

    Adrenaline (1 to 10 microM) can induce the aggregation of human platelets suspended in citrated plasma but does not induce the aggregation of washed human platelets at doses as high as 1 mM, although these platelets respond normally to ADP, PAF-acether, collagen, arachidonic acid, thrombin, the endoperoxide analog U-46619 and the Ca2+ ionophore A23187. Adrenaline (0.5 microM) potentiates the aggregation and secretion induced by all the previous agonists in citrated platelet-rich plasma (cPRP) or in washed platelets. The activation by adrenaline of human platelets is mediated by alpha 2-adrenergic receptors, as demonstrated by inhibition with a series of adrenergic antagonists. The alpha-adrenergic antagonist nicergoline inhibits the activation of human platelets by adrenaline in the following situations: nicergoline inhibits the aggregation and secretion caused by adrenaline in cPRP (IC50 0.22 microM and 0.28 microM respectively); nicergoline inhibits the aggregation and secretion induced by the combination of adrenaline and each aggregating agent listed above in cPRP (IC50 ranging from 0.1 to 2.5 microM) or in washed platelets (IC50 ranging from 0.1 to 0.8 microM); nicergoline inhibits the binding of 3H-yohimbine to washed human platelets (IC50 0.26 microM); the intravenous administration of nicergoline (0.5 mg/kg per day) to patients inhibits significantly the ex vivo response of their platelets to adrenaline in cPRP. High concentrations of nicergoline also inhibit the aggregation and secretion induced by the aggregating agents listed above in cPRP (IC50 range 108 to 670 microM) and in washed platelets (IC50 range 27 to 140 microM) and the adhesion of platelets to collagen-coated surfaces. This latter effect is not mediated through blockade of alpha-adrenoceptors. A possible role of adrenaline in platelet activation in vivo could justify the use of nicergoline (Sermion), an alpha-adrenergic antagonist in combination therapy to prevent arterial thrombosis.

  19. A Recombinant Human Anti-Platelet scFv Antibody Produced in Pichia pastoris for Atheroma Targeting

    PubMed Central

    Vallet-Courbin, Amelie; Larivière, Mélusine; Hocquellet, Agnès; Hemadou, Audrey; Parimala, Sarjapura-Nagaraja; Laroche-Traineau, Jeanny; Santarelli, Xavier; Clofent-Sanchez, Gisèle; Jacobin-Valat, Marie-Josée; Noubhani, Abdelmajid

    2017-01-01

    Cells of the innate and adaptive immune system are key factors in the progression of atherosclerotic plaque, leading to plaque instability and rupture, potentially resulting in acute atherothrombotic events such as coronary artery disease, cerebrovascular disease and peripheral arterial disease. Here, we describe the cloning, expression, purification, and immunoreactivity assessment of a recombinant single-chain variable fragment (scFv) derived from a human anti-αIIbβ3 antibody (HuAb) selected to target atheromatous lesions for the presence of platelets. Indeed, platelets within atheroma plaques have been shown to play a role in inflammation, in platelet-leucocyte aggregates and in thrombi formation and might thus be considered relevant biomarkers of atherosclerotic progression. The DNA sequence that encodes the anti-αIIbβ3 TEG4 scFv previously obtained from a phage-display selection on activated platelets, was inserted into the eukaryote vector (pPICZαA) in fusion with a tag sequence encoding 2 cysteines useable for specific probes grafting experiments. The recombinant protein was expressed at high yields in Pichia pastoris (30 mg/L culture). The advantage of P. pastoris as an expression system is the production and secretion of recombinant proteins in the supernatant, ruling out the difficulties encountered when scFv are produced in the cytoplasm of bacteria (low yield, low solubility and reduced affinity). The improved conditions allowed for the recovery of highly purified and biologically active scFv fragments ready to be grafted in a site-directed way to nanoparticles for the imaging of atherosclerotic plaques involving inflammatory processes and thus at high risk of instability. PMID:28125612

  20. Identification of anti-Lea by platelet complement fixation.

    PubMed

    Ando, B; Ibayashi, H

    1986-01-01

    Two anti-Lea sera which were able to detect Lea antigen on platelets were identified in a screening for anti-platelet antibodies by means of a platelet complement fixation test. These two antisera hemolyzed erythrocytes without enzyme treatment. The anti-Lea activity could be completely absorbed by red cells, platelets and lymphocytes of Le(a+b-) donors but not by cells from Le(a-b+) or Le(a-b-) donors. The antibody activity against red cells was eliminated by treatment of the antisera with dithiothreitol, thereby suggesting that the activity resided in the IgM class of immunoglobulins. As the anti-Lea was more reactive at 37 degrees C than at room temperature against both red cells and platelets, we suggest that transfusion of platelets of Lea-negative donors should be considered for patients with this type of anti-Lea.

  1. Increasing platelet concentration in platelet-rich plasma inhibits anterior cruciate ligament cell function in three-dimensional culture.

    PubMed

    Yoshida, Ryu; Cheng, Mingyu; Murray, Martha M

    2014-02-01

    Tissue engineering is one new strategy being developed to treat ACL ruptures. One such approach is bio-enhanced ACL repair, where a suture repair is supplemented with a bio-active scaffold containing platelets. However, the optimal concentration of platelets to stimulate ACL healing is not known. We hypothesized that increasing platelet concentrations in the scaffold would enhance critical cell behaviors. Porcine ACL fibroblasts were obtained from explant culture and suspended in platelet poor plasma (PPP), 1× platelet-rich plasma (PRP), 3× PRP, 5× PRP, or phosphate buffered saline (PBS). The cell suspensions were cultured in a 3D collagen scaffold. Cellular metabolism (MTT assay), apoptosis (TUNEL assay), and gene expression for type I and type III collagen were measured. 1× PRP significantly outperformed 5× PRP in all parameters studied: Type I and III collagen gene expression, apoptosis prevention, and cell metabolism stimulation. ACL fibroblasts cultured with 1× PRP had the highest type I and type III collagen gene expression. 1× PRP and PPP groups had the highest cell metabolism and lowest apoptosis rates. Concentration of platelets had significant effects on the behavior of ACL fibroblasts; thus, it is an important parameter that should be specified in clinical or basic science studies. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  2. Umbilical Cord Blood Platelet Lysate as Serum Substitute in Expansion of Human Mesenchymal Stem Cells.

    PubMed

    Shirzad, Negin; Bordbar, Sima; Goodarzi, Alireza; Mohammad, Monire; Khosravani, Pardis; Sayahpour, Froughazam; Baghaban Eslaminejad, Mohamadreza; Ebrahimi, Marzieh

    2017-10-01

    The diverse clinical applications for human mesenchymal stem cells (hMSCs) in cellular therapy and regenerative medicine warrant increased focus on developing adequate culture supplements devoid of animal-derived products. In the present study, we have investigated the feasibility of umbilical cord blood-platelet lysate (UCB-PL) as a standard substitute for fetal bovine serum (FBS) and human peripheral blood-PL (PB-PL). In this experimental study, platelet concentrates (PC) from UCB and human PB donors were frozen, melted, and sterilized to obtain PL. Quality control included platelet cell counts, sterility testing (viral and microbial), total protein concentrations, growth factor levels, and PL stability. The effects of UCB-PL and PB-PL on hMSCs proliferation and differentiation into osteocytes, chondrocytes, and adipocytes were studied and the results compared with FBS. UCB-PL contained high levels of protein content, platelet-derived growth factor- AB (PDGF-AB), and transforming growth factor (TGF) compared to PB-PL. All growth factors were stable for at least nine months post-storage at -70˚C. hMSCs proliferation enhanced following treatment with UCB-PL. With all three supplements, hMSCs could differentiate into all three lineages. PB-PL and UCB-PL both were potent in hMSCs proliferation. However, PB promoted osteoblastic differentiation and UCB-PL induced chondrogenic differentiation. Because of availability, ease of use and feasible standardization of UCB-PL, we have suggested that UCB-PL be used as an alternative to FBS and PB-PL for the cultivation and expansion of hMSCs in cellular therapy. Copyright© by Royan Institute. All rights reserved.

  3. In search of a consensus terminology in the field of platelet concentrates for surgical use: platelet-rich plasma (PRP), platelet-rich fibrin (PRF), fibrin gel polymerization and leukocytes.

    PubMed

    Dohan Ehrenfest, David M; Bielecki, Tomasz; Mishra, Allan; Borzini, Piero; Inchingolo, Francesco; Sammartino, Gilberto; Rasmusson, Lars; Everts, Peter A

    2012-06-01

    In the field of platelet concentrates for surgical use, most products are termed Platelet-Rich Plasma (PRP). Unfortunately, this term is very general and incomplete, leading to many confusions in the scientific database. In this article, a panel of experts discusses this issue and proposes an accurate and simple terminology system for platelet concentrates for surgical use. Four main categories of products can be easily defined, depending on their leukocyte content and fibrin architecture: Pure Platelet-Rich Plasma (P-PRP), such as cell separator PRP, Vivostat PRF or Anitua's PRGF; Leukocyteand Platelet-Rich Plasma (L-PRP), such as Curasan, Regen, Plateltex, SmartPReP, PCCS, Magellan, Angel or GPS PRP; Pure Plaletet-Rich Fibrin (P-PRF), such as Fibrinet; and Leukocyte- and Platelet-Rich Fibrin (L-PRF), such as Choukroun's PRF. P-PRP and L-PRP refer to the unactivated liquid form of these products, their activated versions being respectively named P-PRP gels and L-PRP gels. The purpose of this search for a terminology consensus is to plead for a more serious characterization of these products. Researchers have to be aware of the complex nature of these living biomaterials, in order to avoid misunderstandings and erroneous conclusions. Understanding the biomaterials or believing in the magic of growth factors ? From this choice depends the future of the field.

  4. Comparison of the therapeutic effects of ultrasound-guided platelet-rich plasma injection and dry needling in rotator cuff disease: a randomized controlled trial.

    PubMed

    Rha, Dong-wook; Park, Gi-Young; Kim, Yong-Kyun; Kim, Min Tae; Lee, Sang Chul

    2013-02-01

    To compare the effects of platelet-rich plasma injection with those of dry needling on shoulder pain and function in patients with rotator cuff disease. A single-centre, prospective, randomized, double-blinded, controlled study. University rehabilitation hospital. Thirty-nine patients with a supraspinatus tendon lesion (tendinosis or a partial tear less than 1.0 cm, but not a complete tear) who met the inclusion criteria recruited between June 2010 and February 2011. Two dry needling procedures in the control group and two platelet-rich plasma injections in the experimental group were applied to the affected shoulder at four-week intervals using ultrasound guidance. The Shoulder Pain and Disability Index, passive range of motion of the shoulder, a physician global rating scale at the six-month follow-up, adverse effects monitoring and an ultrasound measurement were used as outcome measures. The clinical effect of the platelet-rich plasma injection was superior to the dry needling from six weeks to six months after initial injection (P < 0.05). At six months the mean Shoulder Pain and Disability Index was 17.7 ± 3.7 in the platelet-rich plasma group versus 29.5 ± 3.8 in the dry needling group (P < 0.05). No severe adverse effects were observed in either group. Autologous platelet-rich plasma injections lead to a progressive reduction in the pain and disability when compared to dry needling. This benefit is certainly still present at six months after treatment. These findings suggest that treatment with platelet-rich plasma injections is safe and useful for rotator cuff disease.

  5. The influence of environmental variables on platelet concentration in horse platelet-rich plasma.

    PubMed

    Rinnovati, Riccardo; Romagnoli, Noemi; Gentilini, Fabio; Lambertini, Carlotta; Spadari, Alessandro

    2016-07-04

    Platelet-rich plasma (PRP) commonly refers to blood products which contain a higher platelet (PLT) concentration as compared to normal plasma. Autologous PRP has been shown to be safe and effective in promoting the natural processes of soft tissue healing or reconstruction in humans and horses. Variability in PLT concentration has been observed in practice between PRP preparations from different patients or from the same individual under different conditions. A change in PLT concentration could modify PRP efficacy in routine applications. The aim of this study was to test the influence of environmental, individual and agonistic variables on the PLT concentration of PRP in horses. Six healthy Standardbred mares were exposed to six different variables with a one-week washout period between variables, and PRP was subsequently obtained from each horse. The variables were time of withdrawal during the day (morning/evening), hydration status (overhydration/dehydration) treatment with anti-inflammatory drugs and training periods on a treadmill. The platelet concentration was significantly higher in horses treated with a non-steroidal anti-inflammatory drug (P = 0.03). The leukocyte concentration increased 2-9 fold with respect to whole blood in the PRP which was obtained after exposure to all the variable considered. Environmental variation in platelet concentration should be taken into consideration during PRP preparation.

  6. Platelet-derived HMGB1 is a critical mediator of thrombosis.

    PubMed

    Vogel, Sebastian; Bodenstein, Rebecca; Chen, Qiwei; Feil, Susanne; Feil, Robert; Rheinlaender, Johannes; Schäffer, Tilman E; Bohn, Erwin; Frick, Julia-Stefanie; Borst, Oliver; Münzer, Patrick; Walker, Britta; Markel, Justin; Csanyi, Gabor; Pagano, Patrick J; Loughran, Patricia; Jessup, Morgan E; Watkins, Simon C; Bullock, Grant C; Sperry, Jason L; Zuckerbraun, Brian S; Billiar, Timothy R; Lotze, Michael T; Gawaz, Meinrad; Neal, Matthew D

    2015-12-01

    Thrombosis and inflammation are intricately linked in several major clinical disorders, including disseminated intravascular coagulation and acute ischemic events. The damage-associated molecular pattern molecule high-mobility group box 1 (HMGB1) is upregulated by activated platelets in multiple inflammatory diseases; however, the contribution of platelet-derived HMGB1 in thrombosis remains unexplored. Here, we generated transgenic mice with platelet-specific ablation of HMGB1 and determined that platelet-derived HMGB1 is a critical mediator of thrombosis. Mice lacking HMGB1 in platelets exhibited increased bleeding times as well as reduced thrombus formation, platelet aggregation, inflammation, and organ damage during experimental trauma/hemorrhagic shock. Platelets were the major source of HMGB1 within thrombi. In trauma patients, HMGB1 expression on the surface of circulating platelets was markedly upregulated. Moreover, evaluation of isolated platelets revealed that HMGB1 is critical for regulating platelet activation, granule secretion, adhesion, and spreading. These effects were mediated via TLR4- and MyD88-dependent recruitment of platelet guanylyl cyclase (GC) toward the plasma membrane, followed by MyD88/GC complex formation and activation of the cGMP-dependent protein kinase I (cGKI). Thus, we establish platelet-derived HMGB1 as an important mediator of thrombosis and identify a HMGB1-driven link between MyD88 and GC/cGKI in platelets. Additionally, these findings suggest a potential therapeutic target for patients sustaining trauma and other inflammatory disorders associated with abnormal coagulation.

  7. Global analysis of the rat and human platelet proteome – the molecular blueprint for illustrating multi-functional platelets and cross-species function evolution

    PubMed Central

    Yu, Yanbao; Leng, Taohua; Yun, Dong; Liu, Na; Yao, Jun; Dai, Ying; Yang, Pengyuan; Chen, Xian

    2013-01-01

    Emerging evidences indicate that blood platelets function in multiple biological processes including immune response, bone metastasis and liver regeneration in addition to their known roles in hemostasis and thrombosis. Global elucidation of platelet proteome will provide the molecular base of these platelet functions. Here, we set up a high throughput platform for maximum exploration of the rat/human platelet proteome using integrated proteomics technologies, and then applied to identify the largest number of the proteins expressed in both rat and human platelets. After stringent statistical filtration, a total of 837 unique proteins matched with at least two unique peptides were precisely identified, making it the first comprehensive protein database so far for rat platelets. Meanwhile, quantitative analyses of the thrombin-stimulated platelets offered great insights into the biological functions of platelet proteins and therefore confirmed our global profiling data. A comparative proteomic analysis between rat and human platelets was also conducted, which revealed not only a significant similarity, but also an across-species evolutionary link that the orthologous proteins representing ‘core proteome’, and the ‘evolutionary proteome’ is actually a relatively static proteome. PMID:20443191

  8. Alcohol, wine and platelet function.

    PubMed

    Ruf, Jean-Claude

    2004-01-01

    Epidemiological studies have demonstrated an inverse correlation between moderate wine and alcohol consumption and morbidity and mortality from coronary heart disease. The protective effect has been associated with an increase in the plasma level of HDL cholesterol, as it is well recognized that plasma HDL is inversely correlated with CHD. In addition, it has become evident that blood platelets contribute to the rate of development of atherosclerosis and CHD through several mechanisms. In recent studies it has been shown that the level of HDL cholesterol can explain only 50% of the protective effect of alcoholic beverages; the other 50% may be partly related to a decrease in platelet activity. This anti-platelet activity of wine is explained by ethanol but also by the polyphenolic components with which red wines are richly endowed. Several studies carried out on humans and animals have shown that wine phenolics could exert their effects by reducing prostanoid synthesis from arachidonate. In addition, it has been suggested that wine phenolics could reduce platelet activity mediated by nitric oxide. Moreover, wine phenolics increase vitamin E levels while decreasing the oxidation of platelets submitted to oxidative stress. However, a rebound phenomenon of hyperaggregability is observed after an acute alcohol consumption which is not observed with wine consumption. This protection afforded by wine has been duplicated in animals with grape phenolics added to alcohol. The rebound phenomenon may explain ischemic strokes or sudden deaths known to occur after episodes of drunkenness. It appears that wine, and wine phenolics in particular, could have a more significant inhibitory effect on platelet aggregation and could explain, in part, the hypothesis that red wine is more protective against atherosclerosis and coronary heart disease.

  9. Platelet Function Tests: Preanalytical Variables, Clinical Utility, Advantages, and Disadvantages.

    PubMed

    Hvas, Anne-Mette; Grove, Erik Lerkevang

    2017-01-01

    Platelet function tests are mainly used in the diagnostic work-up of platelet disorders. During the last decade, the additional use of platelet function tests to evaluate the effect of antiplatelet therapy has also emerged in an attempt to identify patients with an increased risk of arterial thrombosis. Furthermore, platelet function tests are increasingly used to measure residual effect of antiplatelet therapy prior to surgery with the aim of reducing the risk of bleeding. To a limited extend, platelet function tests are also used to evaluate hyperaggregability as a potential marker of a prothrombotic state outside the setting of antiplatelet therapy. This multifaceted use of platelet function tests and the development of simpler point-of-care tests with narrower application have increased the use of platelet function testing and also facilitated the use of platelet function tests outside the highly specialized laboratories. The present chapter describes the preanalytical variables, which should be taken into account when planning platelet function testing. Also, the most widely used platelet function tests are introduced, and their clinical utility and their relative advantages and disadvantages are discussed.

  10. Human plasma fibrinogen adsorption and platelet adhesion to polystyrene.

    PubMed

    Tsai, W B; Grunkemeier, J M; Horbett, T A

    1999-02-01

    The purpose of this study was to further investigate the role of fibrinogen adsorbed from plasma in mediating platelet adhesion to polymeric biomaterials. Polystyrene was used as a model hydrophobic polymer; i.e., we expected that the role of fibrinogen in platelet adhesion to polystyrene would be representative of other hydrophobic polymers. Platelet adhesion was compared to both the amount and conformation of adsorbed fibrinogen. The strategy was to compare platelet adhesion to surfaces preadsorbed with normal, afibrinogenemic, and fibrinogen-replenished afibrinogenemic plasmas. Platelet adhesion was determined by the lactate dehydrogenase (LDH) method, which was found to be closely correlated with adhesion of 111In-labeled platelets. Fibrinogen adsorption from afibrinogenemic plasma to polystyrene (Immulon I(R)) was low and <10 ng/cm2. Platelet adhesion was absent on surfaces preadsorbed with afibrinogenemic plasma when the residual fibrinogen was low enough (<60 microg/mL). Platelet adhesion was restored on polystyrene preadsorbed with fibrinogen-replenished afibrinogenemic plasma. Addition of even small, subnormal concentrations of fibrinogen to afibrinogenemic plasma greatly increased platelet adhesion. In addition, surface-bound fibrinogen's ability to mediate platelet adhesion was different, depending on the plasma concentration from which fibrinogen was adsorbed. These differences correlated with changes in the binding of a monoclonal antibody that binds to the Aalpha chain RGDS (572-575), suggesting alteration in the conformation or orientation of the adsorbed fibrinogen. Platelet adhesion to polystyrene preadsorbed with blood plasma thus appears to be a strongly bivariate function of adsorbed fibrinogen, responsive to both low amounts and altered states of the adsorbed molecule. Copyright 1999 John Wiley & Sons, Inc.

  11. Cationic PAMAM dendrimers disrupt key platelet functions

    PubMed Central

    Jones, Clinton F.; Campbell, Robert A.; Franks, Zechariah; Gibson, Christopher C.; Thiagarajan, Giridhar; Vieira-de-Abreu, Adriana; Sukavaneshvar, Sivaprasad; Mohammad, S. Fazal; Li, Dean Y.; Ghandehari, Hamidreza; Weyrich, Andrew S.; Brooks, Benjamin D.; Grainger, David W.

    2012-01-01

    Poly(amidoamine) (PAMAM) dendrimers have been proposed for a variety of biomedical applications and are increasingly studied as model nanomaterials for such use. The dendritic structure features both modular synthetic control of molecular size and shape and presentation of multiple equivalent terminal groups. These properties make PAMAM dendrimers highly functionalizable, versatile single-molecule nanoparticles with a high degree of consistency and low polydispersity. Recent nanotoxicological studies showed that intravenous administration of amine-terminated PAMAM dendrimers to mice was lethal, causing a disseminated intravascular coagulation-like condition. To elucidate the mechanisms underlying this coagulopathy, in vitro assessments of platelet functions in contact with PAMAM dendrimers were undertaken. This study demonstrates that cationic G7 PAMAM dendrimers activate platelets and dramatically alter their morphology. These changes to platelet morphology and activation state substantially altered platelet function, including increased aggregation and adherence to surfaces. Surprisingly, dendrimer exposure also attenuated platelet-dependent thrombin generation, indicating that not all platelet functions remained intact. These findings provide additional insight into PAMAM dendrimer effects on blood components and underscore the necessity for further research on the effects and mechanisms of PAMAM-specific and general nanoparticle toxicity in blood. PMID:22497592

  12. Platelets Toll-like receptor-4 in Crohns disease.

    PubMed

    Schmid, Werner; Novacek, Gottfried; Vogelsang, Harald; Papay, Pavol; Primas, Christian; Eser, Alexander; Panzer, Simon

    2017-02-01

    Platelets are activated in Crohn's disease (CD) and interplay with leukocytes. Engagement of Toll-like receptor-4 (TLR-4), which is expressed in human platelets, may be involved in crosstalks between platelets and leukocytes leading to their mutual activation for host defense. Human neutrophil peptides (HNPs), lipoprotein binding peptides, and sCD14 were determined by enzyme-linked immunosorbent assays in 42 patients with active CD, in 43 patients with CD in remission, and in 30 healthy individuals. Neutrophil-platelet aggregates and binding of the TLR-4 monoclonal antibody to platelets were determined by flow cytometry. Levels of HNPs were higher in patients with CD than in controls (P = 0.0003 vs. active CD and P = 0.01 vs. CD in remission). Likewise, neutrophils with adhering platelets were higher in patients with active CD than in controls (P = 0.004). Binding of the TLR-4 antibody in patients with active CD was similar to that in controls, while patients in remission had significantly higher binding capacities (P = 0.59 and P = 0.003). Incubation of plasma from patients with active disease or patients in remission with platelets from healthy controls confirmed lower binding of the TLR-4 antibody in the presence of plasma from active diseased patients compared to controls (P = 0.039), possibly due to high levels of lipopolysaccharides, as suggested by high levels of sCD14 and lipoprotein binding protein. Our study indicates involvement of platelet TLR-4 in enhancing the secretion of antimicrobial peptides from neutrophils. While platelet aggregation can be due to a variety of mechanisms in inflammatory disease, the mutual activation of platelets and neutrophils may augment host defense. © 2016 Stichting European Society for Clinical Investigation Journal Foundation.

  13. Thioredoxin Inhibitors Attenuate Platelet Function and Thrombus Formation

    PubMed Central

    Metcalfe, Clive; Ramasubramoni, Anjana; Pula, Giordano; Harper, Matthew T.; Mundell, Stuart J.; Coxon, Carmen H.

    2016-01-01

    Thioredoxin (Trx) is an oxidoreductase with important physiological function. Imbalances in the NADPH/thioredoxin reductase/thioredoxin system are associated with a number of pathologies, particularly cancer, and a number of clinical trials for thioredoxin and thioredoxin reductase inhibitors have been carried out or are underway. Due to the emerging role and importance of oxidoreductases for haemostasis and the current interest in developing inhibitors for clinical use, we thought it pertinent to assess whether inhibition of the NADPH/thioredoxin reductase/thioredoxin system affects platelet function and thrombosis. We used small molecule inhibitors of Trx (PMX 464 and PX-12) to determine whether Trx activity influences platelet function, as well as an unbiased proteomics approach to identify potential Trx substrates on the surface of platelets that might contribute to platelet reactivity and function. Using LC-MS/MS we found that PMX 464 and PX-12 affected the oxidation state of thiols in a number of cell surface proteins. Key surface receptors for platelet adhesion and activation were affected, including the collagen receptor GPVI and the von Willebrand factor receptor, GPIb. To experimentally validate these findings we assessed platelet function in the presence of PMX 464, PX-12, and rutin (a selective inhibitor of the related protein disulphide isomerase). In agreement with the proteomics data, small molecule inhibitors of thioredoxin selectively inhibited GPVI-mediated platelet activation, and attenuated ristocetin-induced GPIb-vWF-mediated platelet agglutination, thus validating the findings of the proteomics study. These data reveal a novel role for thioredoxin in regulating platelet reactivity via proteins required for early platelet responses at sites of vessel injury (GPVI and GPIb). This work also highlights a potential opportunity for repurposing of PMX 464 and PX-12 as antiplatelet agents. PMID:27716777

  14. Thioredoxin Inhibitors Attenuate Platelet Function and Thrombus Formation.

    PubMed

    Metcalfe, Clive; Ramasubramoni, Anjana; Pula, Giordano; Harper, Matthew T; Mundell, Stuart J; Coxon, Carmen H

    2016-01-01

    Thioredoxin (Trx) is an oxidoreductase with important physiological function. Imbalances in the NADPH/thioredoxin reductase/thioredoxin system are associated with a number of pathologies, particularly cancer, and a number of clinical trials for thioredoxin and thioredoxin reductase inhibitors have been carried out or are underway. Due to the emerging role and importance of oxidoreductases for haemostasis and the current interest in developing inhibitors for clinical use, we thought it pertinent to assess whether inhibition of the NADPH/thioredoxin reductase/thioredoxin system affects platelet function and thrombosis. We used small molecule inhibitors of Trx (PMX 464 and PX-12) to determine whether Trx activity influences platelet function, as well as an unbiased proteomics approach to identify potential Trx substrates on the surface of platelets that might contribute to platelet reactivity and function. Using LC-MS/MS we found that PMX 464 and PX-12 affected the oxidation state of thiols in a number of cell surface proteins. Key surface receptors for platelet adhesion and activation were affected, including the collagen receptor GPVI and the von Willebrand factor receptor, GPIb. To experimentally validate these findings we assessed platelet function in the presence of PMX 464, PX-12, and rutin (a selective inhibitor of the related protein disulphide isomerase). In agreement with the proteomics data, small molecule inhibitors of thioredoxin selectively inhibited GPVI-mediated platelet activation, and attenuated ristocetin-induced GPIb-vWF-mediated platelet agglutination, thus validating the findings of the proteomics study. These data reveal a novel role for thioredoxin in regulating platelet reactivity via proteins required for early platelet responses at sites of vessel injury (GPVI and GPIb). This work also highlights a potential opportunity for repurposing of PMX 464 and PX-12 as antiplatelet agents.

  15. Prevention of red cell storage lesion: a comparison of five different additive solutions.

    PubMed

    Lagerberg, Johan W; Korsten, Herbert; Van Der Meer, Pieter F; De Korte, Dirk

    2017-09-01

    In Europe, red cell concentrates (RCC) are usually stored in SAGM (saline-adenine-glucose-mannitol). During storage, in vitro red cell quality declines, including lowered energy status and increased cell lysis. Recently, several additive solutions (ASs), designed to diminish the decline in in vitro quality during storage, have been developed. These new solutions have mainly been developed to better maintain red blood cell (RBC) 2,3-biphosphoglycerate (2,3 BPG) levels and energy status during storage. High levels of 2,3 BPG allow for better oxygen release while high energy status is necessary for function and survival of RBC in vivo. In a paired study design, RBC ASs were compared for their ability to provide improved in vitro quality during hypothermic storage. For each experiment, 5 whole blood units held overnight were pooled and split. The whole blood units were processed according to the buffy coat method. RBCs were resuspended in either SAGM, PAGGSM, PAG3M, E-Sol 5 or AS-7 and leucoreduced by filtration. RCCs were stored for eight weeks at 2-6 °C and sampled weekly for analysis of in vitro quality parameters. Red cell concentrates stored in PAG3M, E-Sol 5 and AS-7 showed significantly higher lactate production and higher levels of intracellular adenosine triphosphate (ATP) and total adenylate. 2,3 BPG levels rapidly declined during storage in SAGM and PAGGSM. The decline in 2,3 BPG was inhibited during storage in E-Sol 5 and AS-7, while in PAG3M, 2,3 BPG level increased above the initial level till day 35 and remained detectable till day 56. Haemolysis was comparable for all ASs until day 35, upon prolonged storage, haemolysis in SAGM was higher than with the other ASs. As compared to SAGM, storage in PAGGSM, PAG3M, E-Sol 5 and AS-7 better maintained morphological properties. Storage of RBCs in the new generation ASs yield RBCs with more stable metabolite levels and improved overall quality during storage as compared with RBCs stored in SAGM.

  16. Platelet-rich plasma: combinational treatment modalities for musculoskeletal conditions.

    PubMed

    Andia, Isabel; Abate, Michele

    2018-04-01

    Current research on common musculoskeletal problems, including osteoarticular conditions, tendinopathies, and muscle injuries, focuses on regenerative translational medicine. Platelet-rich plasma therapies have emerged as a potential approach to enhance tissue repair and regeneration. Platelet-rich plasma application aims to provide supraphysiological concentrations of platelets and optionally leukocytes at injured/pathological tissues mimicking the initial stages of healing. However, the efficacy of platelet-rich plasma is controversial in chronic diseases because patients' outcomes show partial improvements. Platelet-rich plasma can be customized to specific conditions by selecting the most appropriate formulation and timing for application or by combining platelet-rich plasma with synergistic or complementary treatments. To achieve this goal, researchers should identify and enhance the main mechanisms of healing. In this review, the interactions between platelet-rich plasma and healing mechanisms were addressed and research opportunities for customized treatment modalities were outlined. The development of combinational platelet-rich plasma treatments that can be used safely and effectively to manipulate healing mechanisms would be valuable and would provide insights into the processes involved in physiological healing and pathological failure.

  17. Platelet Aggregometry Testing: Molecular Mechanisms, Techniques and Clinical Implications

    PubMed Central

    Koltai, Katalin; Kesmarky, Gabor; Feher, Gergely; Tibold, Antal

    2017-01-01

    Platelets play a fundamental role in normal hemostasis, while their inherited or acquired dysfunctions are involved in a variety of bleeding disorders or thrombotic events. Several laboratory methodologies or point-of-care testing methods are currently available for clinical and experimental settings. These methods describe different aspects of platelet function based on platelet aggregation, platelet adhesion, the viscoelastic properties during clot formation, the evaluation of thromboxane metabolism or certain flow cytometry techniques. Platelet aggregometry is applied in different clinical settings as monitoring response to antiplatelet therapies, the assessment of perioperative bleeding risk, the diagnosis of inherited bleeding disorders or in transfusion medicine. The rationale for platelet function-driven antiplatelet therapy was based on the result of several studies on patients undergoing percutaneous coronary intervention (PCI), where an association between high platelet reactivity despite P2Y12 inhibition and ischemic events as stent thrombosis or cardiovascular death was found. However, recent large scale randomized, controlled trials have consistently failed to demonstrate a benefit of personalised antiplatelet therapy based on platelet function testing. PMID:28820484

  18. Platelet aggregation responses in clinically healthy adult llamas.

    PubMed

    Gilbert, Rosanne M; Bird, Karyn E; Kutzler, Michelle A

    2009-03-01

    Limited information exists regarding hemostasis in camelids despite the importance of platelet function testing in the accurate identification of platelet disorders. As further importation of llamas to North America is restricted, variability in breeding stock will continue to decrease, potentially leading to an increase in heritable bleeding disorders. The objective of this study was to measure platelet aggregation responses in clinically healthy llamas and provide baseline data to which abnormal platelet function may be compared in the future. Blood samples were collected from 39 healthy adult llamas, citrated, and centrifuged to produce platelet-rich plasma (PRP). Within 4 hours of the blood draw, 20 microL of each agonist reagent were added to 180 microL of PRP. Final concentrations of agonists were 2 x 10(-5) M ADP, 0.19 mg collagen/mL PRP, 1 x 10(-4) M epinephrine, and 500 microg arachidonic acid/mL PRP. Llama platelets were most responsive to ADP and collagen, with a maximum percent aggregation (mean+/-SD) of 71.3+/-18.6% and 55.8+/-19% and aggregation rates of 9.5+/-3.9 and 6.7+/-3.7 cm/min, respectively. Llama platelet aggregation in response to epinephrine and arachidonic acid was minimal to absent. This study is the first of its kind to establish baseline values for platelet aggregation in healthy adult llamas.

  19. [Influence of raising oxygen content on function of platelet concentrate during preservation].

    PubMed

    Zhan, Tong; Xiao, Jian-Yu; Tao, Jing; Miao, Xi-Feng; Liu, Yan-Cun; Tang, Rong-Cai

    2006-08-01

    To explore the influence of raising oxygen (dissolved oxygen) content on function of platelet concentrate, the platelet concentrate was prepared by a CS-3000 plus blood cell separator. Experiments were divided into 2 groups: test group and control group. After raising oxygen content in platelet plasma under sterile operation, the platelet samples of two groups were preserved in oscillator with horizontal oscillation at 22 +/- 2 degrees C. The platelet count, platelet aggregation rate, lactic acid content and CD62p expression level of platelet were detected on 0, 1, 2, 3, 4, 5 days of platelet preservation. The results showed that the platelet count and platelet aggregation rate decreased with prolongation of preserved time, while the lactic acid content and CD62p expression level of platelet increased gradually. Compared with control group, there were significant differences in aggregation rate of platelet preserved for 2-3 days, and in CD62p expression level of platelet preserved for 1-3 days, while significant difference was found in lactic acid content of platelet preserved for 1-3 days. It is concluded that raising content of oxygen in platelet plasma can provide more oxygen to compensate oxygen supply deficiency for platelet metabolism and improve the efficiency of platelet oxygenic metabolism and the quality of platelet during preservation.

  20. Platelet proteomics: from discovery to diagnosis.

    PubMed

    Looße, Christina; Swieringa, Frauke; Heemskerk, Johan W M; Sickmann, Albert; Lorenz, Christin

    2018-05-22

    Platelets are the smallest cells within the circulating blood with key roles in physiological haemostasis and pathological thrombosis regulated by the onset of activating/inhibiting processes via receptor responses and signalling cascades. Areas covered: Proteomics as well as genomic approaches have been fundamental in identifying and quantifying potential targets for future diagnostic strategies in the prevention of bleeding and thrombosis, and uncovering the complexity of platelet functions in health and disease. In this article, we provide a critical overview on current functional tests used in diagnostics and the future perspectives for platelet proteomics in clinical applications. Expert commentary: Proteomics represents a valuable tool for the identification of patients with diverse platelet associated defects. In-depth validation of identified biomarkers, e.g. receptors, signalling proteins, post-translational modifications, in large cohorts is decisive for translation into routine clinical diagnostics.

  1. Assessment of platelet function in healthy cats in response to commonly prescribed antiplatelet drugs using three point-of-care platelet function tests.

    PubMed

    Ho, Kimberly K; Abrams-Ogg, Anthony Cg; Wood, R Darren; O'Sullivan, M Lynne; Kirby, Gordon M; Blois, Shauna L

    2017-06-01

    Objectives The objective was to determine if decreased platelet function could be detected after treatment with aspirin and/or clopidogrel in healthy cats using three point-of-care platelet function tests that evaluate platelet function by different methods: Multiplate (by impedance), Platelet Function Analyzer 100 (by mechanical aperture closure) and Plateletworks (by platelet counting). Methods Thirty-six healthy cats were randomly assigned to receive one of three oral treatments over an 8 day period: (1) aspirin 5 mg q72h; (2) aspirin 20.25 mg q72h; or (3) clopidogrel 18.75 mg q24h. Cats treated with 5 and 20.25 mg aspirin also received clopidogrel on days 4-8. Platelet aggregation in response to adenosine diphosphate and collagen ± arachidonic acid was assessed on days 1 (baseline), 4 and 8. Aspirin and clopidogrel metabolites were measured by high-performance liquid chromatography. Platelet function in response to treatment was analyzed by ANCOVA, linear regression and Spearman correlation. Results The only solitary aspirin effect was detected using Plateletworks with collagen in cats treated with 20.25 mg. The only effect detected by Multiplate was using arachidonic acid in cats treated with both aspirin 20.25 mg and clopidogrel. All clopidogrel treatment effects were detected by Platelet Function Analyzer 100, Plateletworks (adenosine diphosphate) and Plateletworks (collagen). Drug metabolites were present in all cats, but concentrations were minimally correlated to platelet function test results. Conclusions and relevance Platelet Function Analyzer 100 and Plateletworks using adenosine diphosphate ± collagen agonists may be used to detect decreased platelet function in response to clopidogrel treatment. Either aspirin is not as effective an antiplatelet drug as clopidogrel, or the tests used were not optimal to measure aspirin effect. Cats with heart disease are commonly prescribed antiplatelet drugs to decrease the risk of aortic thromboembolism

  2. Platelets and their interactions with other immune cells

    PubMed Central

    Lam, Fong W.; Vijayan, K. Vinod; Rumbaut, Rolando E.

    2015-01-01

    Platelets are anucleate blood cells, long known to be critically involved in hemostasis and thrombosis. In addition to their role in blood clots, increasing evidence reveals significant roles for platelets in inflammation and immunity. However, the notion that platelets represent immune cells is not broadly recognized in the field of Physiology. This manuscript reviews the role of platelets in inflammation and immune responses, and highlights their interactions with other immune cells, including examples of major functional consequences of these interactions. PMID:26140718

  3. Does platelet count in platelet-rich plasma influence slope, maximal amplitude and lag phase in healthy individuals? Results of light transmission aggregometry.

    PubMed

    Chandrashekar, Vani

    2015-01-01

    Light transmission aggregometry lacks in standardisation and normal reference values are not widely available. The aims of our study were to establish reference ranges for aggregation, slope and lag phase in healthy controls with platelet counts between 150 and 450 × 10(9)/l in platelet-rich plasma (PRP) as well as evaluate the influence of platelet count. Ninety-nine subjects were evaluated with four agonists and divided into two groups based on platelet count and the groups were compared by Student's t-test. There was no difference between the means of the two groups for amplitude and slope barring the lag phase for collagen. Platelet counts between 150 and 450 × 10(9)/l have no effects on light transmission aggregometry and hence adjustment of platelet count is not necessary.

  4. Scalable Generation of Universal Platelets from Human Induced Pluripotent Stem Cells

    PubMed Central

    Feng, Qiang; Shabrani, Namrata; Thon, Jonathan N.; Huo, Hongguang; Thiel, Austin; Machlus, Kellie R.; Kim, Kyungho; Brooks, Julie; Li, Feng; Luo, Chenmei; Kimbrel, Erin A.; Wang, Jiwu; Kim, Kwang-Soo; Italiano, Joseph; Cho, Jaehyung; Lu, Shi-Jiang; Lanza, Robert

    2014-01-01

    Summary Human induced pluripotent stem cells (iPSCs) provide a potentially replenishable source for the production of transfusable platelets. Here, we describe a method to generate megakaryocytes (MKs) and functional platelets from iPSCs in a scalable manner under serum/feeder-free conditions. The method also permits the cryopreservation of MK progenitors, enabling a rapid “surge” capacity when large numbers of platelets are needed. Ultrastructural/morphological analyses show no major differences between iPSC platelets and human blood platelets. iPSC platelets form aggregates, lamellipodia, and filopodia after activation and circulate in macrophage-depleted animals and incorporate into developing mouse thrombi in a manner identical to human platelets. By knocking out the β2-microglobulin gene, we have generated platelets that are negative for the major histocompatibility antigens. The scalable generation of HLA-ABC-negative platelets from a renewable cell source represents an important step toward generating universal platelets for transfusion as well as a potential strategy for the management of platelet refractoriness. PMID:25418726

  5. Scalable generation of universal platelets from human induced pluripotent stem cells.

    PubMed

    Feng, Qiang; Shabrani, Namrata; Thon, Jonathan N; Huo, Hongguang; Thiel, Austin; Machlus, Kellie R; Kim, Kyungho; Brooks, Julie; Li, Feng; Luo, Chenmei; Kimbrel, Erin A; Wang, Jiwu; Kim, Kwang-Soo; Italiano, Joseph; Cho, Jaehyung; Lu, Shi-Jiang; Lanza, Robert

    2014-11-11

    Human induced pluripotent stem cells (iPSCs) provide a potentially replenishable source for the production of transfusable platelets. Here, we describe a method to generate megakaryocytes (MKs) and functional platelets from iPSCs in a scalable manner under serum/feeder-free conditions. The method also permits the cryopreservation of MK progenitors, enabling a rapid "surge" capacity when large numbers of platelets are needed. Ultrastructural/morphological analyses show no major differences between iPSC platelets and human blood platelets. iPSC platelets form aggregates, lamellipodia, and filopodia after activation and circulate in macrophage-depleted animals and incorporate into developing mouse thrombi in a manner identical to human platelets. By knocking out the β2-microglobulin gene, we have generated platelets that are negative for the major histocompatibility antigens. The scalable generation of HLA-ABC-negative platelets from a renewable cell source represents an important step toward generating universal platelets for transfusion as well as a potential strategy for the management of platelet refractoriness.

  6. Staurosporine potentiates platelet activating factor stimulated phospholipase C activity in rabbit platelets but does not block desensitization by platelet activating factor.

    PubMed

    Morrison, W J; Dhar, A; Shukla, S D

    1989-01-01

    The possible involvement of protein kinase C activation in regulating PAF-stimulated PLC activity was studied in rabbit platelets. PAF (100 nM for 5 seconds) stimulated incorporation of 32P into proteins and caused [3H]InsP3 levels to increase about 260% of control. These responses were compared after platelets were pretreated with either PAF, phorbol 12-myristate 13-acetate (PMA) or staurosporine and also after pretreatments with staurosporine followed by PAF or PMA. Pretreating platelets with staurosporine potentiated PAF-stimulated [3H]InsP3 levels by 54% and blocked protein phosphorylation. Pretreatments with PAF and PMA caused PAF-stimulated [3H]InsP3 levels to decrease to 115 and 136%, respectively. Staurosporine pretreatment blocked the decrease caused by the PMA pretreatment but not that by PAF. This study demonstrates that PAF-stimulated PLC activity is negatively affected by protein kinase C (PKC) activation and that inhibition of PKC activity did not prevent desensitization of PLC by PAF.

  7. Single-platelet nanomechanics measured by high-throughput cytometry

    NASA Astrophysics Data System (ADS)

    Myers, David R.; Qiu, Yongzhi; Fay, Meredith E.; Tennenbaum, Michael; Chester, Daniel; Cuadrado, Jonas; Sakurai, Yumiko; Baek, Jong; Tran, Reginald; Ciciliano, Jordan C.; Ahn, Byungwook; Mannino, Robert G.; Bunting, Silvia T.; Bennett, Carolyn; Briones, Michael; Fernandez-Nieves, Alberto; Smith, Michael L.; Brown, Ashley C.; Sulchek, Todd; Lam, Wilbur A.

    2017-02-01

    Haemostasis occurs at sites of vascular injury, where flowing blood forms a clot, a dynamic and heterogeneous fibrin-based biomaterial. Paramount in the clot's capability to stem haemorrhage are its changing mechanical properties, the major drivers of which are the contractile forces exerted by platelets against the fibrin scaffold. However, how platelets transduce microenvironmental cues to mediate contraction and alter clot mechanics is unknown. This is clinically relevant, as overly softened and stiffened clots are associated with bleeding and thrombotic disorders. Here, we report a high-throughput hydrogel-based platelet-contraction cytometer that quantifies single-platelet contraction forces in different clot microenvironments. We also show that platelets, via the Rho/ROCK pathway, synergistically couple mechanical and biochemical inputs to mediate contraction. Moreover, highly contractile platelet subpopulations present in healthy controls are conspicuously absent in a subset of patients with undiagnosed bleeding disorders, and therefore may function as a clinical diagnostic biophysical biomarker.

  8. Rare platelet GPCR variants: what can we learn?

    PubMed

    Nisar, S P; Jones, M L; Cunningham, M R; Mumford, A D; Mundell, S J

    2015-07-01

    Platelet-expressed GPCRs are critical regulators of platelet function. Pharmacological blockade of these receptors forms a powerful therapeutic tool in the treatment and prevention of arterial thrombosis associated with coronary atherosclerosis and ischaemic stroke. However, anti-thrombotic drug therapy is associated with high inter-patient variability in therapeutic response and adverse bleeding side effects. In order to optimize the use of existing anti-platelet drugs and to develop new therapies, more detailed knowledge is required relating to the molecular mechanisms that regulate GPCR and therefore platelet function. One approach has been to identify rare, function-disrupting mutations within key platelet proteins in patients with bleeding disorders. In this review, we describe how an integrated functional genomics strategy has contributed important structure-function information about platelet GPCRs with specific emphasis upon purinergic and thromboxane A2 receptors. We also discuss the potential implications these findings have for pharmacotherapy and for understanding the molecular basis of mild bleeding disorders. © 2014 The British Pharmacological Society.

  9. Potential fluid mechanic pathways of platelet activation.

    PubMed

    Shadden, Shawn C; Hendabadi, Sahar

    2013-06-01

    Platelet activation is a precursor for blood clotting, which plays leading roles in many vascular complications and causes of death. Platelets can be activated by chemical or mechanical stimuli. Mechanically, platelet activation has been shown to be a function of elevated shear stress and exposure time. These contributions can be combined by considering the cumulative stress or strain on a platelet as it is transported. Here, we develop a framework for computing a hemodynamic-based activation potential that is derived from a Lagrangian integral of strain rate magnitude. We demonstrate that such a measure is generally maximized along, and near to, distinguished material surfaces in the flow. The connections between activation potential and these structures are illustrated through stenotic flow computations. We uncover two distinct structures that may explain observed thrombus formation at the apex and downstream of stenoses. More broadly, these findings suggest fundamental relationships may exist between potential fluid mechanic pathways for mechanical platelet activation and the mechanisms governing their transport.

  10. Potential fluid mechanic pathways of platelet activation

    PubMed Central

    Shadden, Shawn C.; Hendabadi, Sahar

    2012-01-01

    Platelet activation is a precursor for blood clotting, which plays leading roles in many vascular complications and causes of death. Platelets can be activated by chemical or mechanical stimuli. Mechanically, platelet activation has been shown to be a function of elevated shear stress and exposure time. These contributions can be combined by considering the cumulative stress or strain on a platelet as it is transported. Here we develop a framework for computing a hemodynamic-based activation potential that is derived from a Lagrangian integral of strain rate magnitude. We demonstrate that such a measure is generally maximized along, and near to, distinguished material surfaces in the flow. The connections between activation potential and these structures are illustrated through stenotic flow computations. We uncover two distinct structures that may explain observed thrombus formation at the apex and downstream of stenoses. More broadly, these findings suggest fundamental relationships may exist between potential fluid mechanic pathways for mechanical platelet activation and the mechanisms governing their transport. PMID:22782543

  11. Classification of platelet concentrates (Platelet-Rich Plasma-PRP, Platelet-Rich Fibrin-PRF) for topical and infiltrative use in orthopedic and sports medicine: current consensus, clinical implications and perspectives

    PubMed Central

    Dohan Ehrenfest, David M.; Andia, Isabel; Zumstein, Matthias A.; Zhang, Chang-Qing; Pinto, Nelson R.; Bielecki, Tomasz

    2014-01-01

    Summary Platelet concentrates for topical and infiltrative use – commonly termed Platetet-Rich Plasma (PRP) or Platelet-Rich Fibrin (PRF) – are used or tested as surgical adjuvants or regenerative medicine preparations in most medical fields, particularly in sports medicine and orthopaedic surgery. Even if these products offer interesting therapeutic perspectives, their clinical relevance is largely debated, as the literature on the topic is often confused and contradictory. The long history of these products was always associated with confusions, mostly related to the lack of consensual terminology, characterization and classification of the many products that were tested in the last 40 years. The current consensus is based on a simple classification system dividing the many products in 4 main families, based on their fibrin architecture and cell content: Pure Platelet-Rich Plasma (P-PRP), such as the PRGF-Endoret technique; Leukocyte- and Platelet-Rich Plasma (LPRP), such as Biomet GPS system; Pure Platelet-Rich Fibrin (P-PRF), such as Fibrinet; Leukocyte- and Platelet-Rich Fibrin (L-PRF), such as Intra-Spin L-PRF. The 4 main families of products present different biological signatures and mechanisms, and obvious differences for clinical applications. This classification serves as a basis for further investigations of the effects of these products. Perspectives of evolutions of this classification and terminology are also discussed, particularly concerning the impact of the cell content, preservation and activation on these products in sports medicine and orthopaedics. PMID:24932440

  12. Classification of platelet concentrates (Platelet-Rich Plasma-PRP, Platelet-Rich Fibrin-PRF) for topical and infiltrative use in orthopedic and sports medicine: current consensus, clinical implications and perspectives.

    PubMed

    Dohan Ehrenfest, David M; Andia, Isabel; Zumstein, Matthias A; Zhang, Chang-Qing; Pinto, Nelson R; Bielecki, Tomasz

    2014-01-01

    Platelet concentrates for topical and infiltrative use - commonly termed Platetet-Rich Plasma (PRP) or Platelet-Rich Fibrin (PRF) - are used or tested as surgical adjuvants or regenerative medicine preparations in most medical fields, particularly in sports medicine and orthopaedic surgery. Even if these products offer interesting therapeutic perspectives, their clinical relevance is largely debated, as the literature on the topic is often confused and contradictory. The long history of these products was always associated with confusions, mostly related to the lack of consensual terminology, characterization and classification of the many products that were tested in the last 40 years. The current consensus is based on a simple classification system dividing the many products in 4 main families, based on their fibrin architecture and cell content: Pure Platelet-Rich Plasma (P-PRP), such as the PRGF-Endoret technique; Leukocyte- and Platelet-Rich Plasma (LPRP), such as Biomet GPS system; Pure Platelet-Rich Fibrin (P-PRF), such as Fibrinet; Leukocyte- and Platelet-Rich Fibrin (L-PRF), such as Intra-Spin L-PRF. The 4 main families of products present different biological signatures and mechanisms, and obvious differences for clinical applications. This classification serves as a basis for further investigations of the effects of these products. Perspectives of evolutions of this classification and terminology are also discussed, particularly concerning the impact of the cell content, preservation and activation on these products in sports medicine and orthopaedics.

  13. Thrombopoietin contributes to enhanced platelet activation in patients with unstable angina.

    PubMed

    Lupia, Enrico; Bosco, Ornella; Bergerone, Serena; Dondi, Anna Erna; Goffi, Alberto; Oliaro, Elena; Cordero, Marco; Del Sorbo, Lorenzo; Trevi, Giampaolo; Montrucchio, Giuseppe

    2006-12-05

    We sought to investigate the potential role of elevated levels of thrombopoietin (TPO) in platelet activation during unstable angina (UA). Thrombopoietin is a humoral growth factor that does not induce platelet aggregation per se, but primes platelet activation in response to several agonists. No data concerning its contribution to platelet function abnormalities described in patients with UA are available. We studied 15 patients with UA and, as controls, 15 patients with stable angina (SA) and 15 healthy subjects. We measured TPO and C-reactive protein (CRP), as well as monocyte-platelet binding and the platelet expression of P-selectin and of the TPO receptor, c-Mpl. The priming activity of patient or control plasma on platelet aggregation and monocyte-platelet binding and the role of TPO in this effect also were studied. Patients with UA showed higher circulating TPO levels, as well as increased monocyte-platelet binding, platelet P-selectin expression, and CRP levels, than those with SA and healthy control subjects. The UA patients also showed reduced platelet expression of the TPO receptor, c-Mpl. In vitro, the plasma from UA patients, but not from SA patients or healthy controls, primed platelet aggregation and monocyte-platelet binding, which were both reduced when an inhibitor of TPO was used. Thrombopoietin may enhance platelet activation in the early phases of UA, potentially participating in the pathogenesis of acute coronary syndromes.

  14. BH3-mimetic ABT-737 induces strong mitochondrial membrane depolarization in platelets but only weakly stimulates apoptotic morphological changes, platelet shrinkage and microparticle formation.

    PubMed

    Gyulkhandanyan, Armen V; Mutlu, Asuman; Allen, David J; Freedman, John; Leytin, Valery

    2014-01-01

    Depolarization of mitochondrial inner transmembrane potential (ΔΨm) is a key biochemical manifestation of the intrinsic apoptosis pathway in anucleate platelets. Little is known, however, about the relationship between ΔΨm depolarization and downstream morphological manifestations of platelet apoptosis, cell shrinkage and microparticle (MP) formation. To elucidate this relationship in human platelets. Using flow cytometry, we analyzed ΔΨm depolarization, platelet shrinkage and MP formation in platelets treated with BH3-mimetic ABT-737 and calcium ionophore A23187, well-known inducers of intrinsic platelet apoptosis. We found that at optimal treatment conditions (90min, 37°C) both ABT-737 and A23187 induce ΔΨm depolarization in the majority (88-94%) of platelets and strongly increase intracellular free calcium. In contrast, effects of A23187 and ABT-737 on platelet shrinkage and MP formation are quite different. A23187 strongly stimulates cell shrinkage and MP formation, whereas ABT-737 only weakly induces these events (10-20% of the effect seen with A23187, P<0.0001). These data indicate that a high level of ΔΨm depolarization and intracellular free calcium does not obligatorily ensure strong platelet shrinkage and MP formation. Since ABT-737 efficiently induces clearance of platelets from the circulation, our results suggest that platelet clearance may occur in the absence of the morphological manifestations of apoptosis. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  15. Physiopathology of blood platelets and development of platelets substitutes. Progress report, August 1, 1976--October 31, 1977. [/sup 51/Cr

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Baldini, M G

    1977-07-31

    Progress is reported on the following research projects: the effect of estrogen on platelet aggregability and thrombus formation; the antithrombotic effect of platelet inhibiting agents in a bench model of artificial kidney; the arrest of hemorrhage in severely alloimmunized thrombocytopenic patients; and in vivo elution of /sup 51/Cr from labeled platelets induced by antibody. (HLW)

  16. Platelets in pulmonary vascular physiology and pathology

    PubMed Central

    Kroll, Michael H.; Afshar-Kharghan, Vahid

    2012-01-01

    Almost a trillion platelets pass through the pulmonary circulation every minute, yet little is known about how they support pulmonary physiology or contribute to the pathogenesis of lung diseases. When considering this conundrum, three questions jump out: Does platelet production in the lungs occur? Why does severe thrombocytopenia—which undercuts the principal physiological role of platelets to effect hemostasis—not lead to pulmonary hemorrhage? Why does atherothrombosis—which platelets initiate, maintain, and trigger is other critically important arterial beds—not develop in the pulmonary artery? The purpose of this review is to explore these and derivative questions by providing data within a conceptual framework that begins to organize a subject that is largely unassembled. PMID:23130099

  17. Platelet factor XIIIa release during platelet aggregation and plasma clot strength measured by thrombelastography in patients with coronary artery disease treated with clopidogrel.

    PubMed

    Kreutz, Rolf P; Owens, Janelle; Lu, Deshun; Nystrom, Perry; Jin, Yan; Kreutz, Yvonne; Desta, Zeruesenay; Flockhart, David A

    2015-01-01

    It has been estimated that up to half of circulating factor XIIIa (FXIIIa) is stored in platelets. The release of FXIIIa from platelets upon stimulation with adenosine diphosphate (ADP) in patients with coronary artery disease treated with dual antiplatelet therapy has not been previously examined. Samples from 96 patients with established coronary artery disease treated with aspirin and clopidogrel were examined. Platelet aggregation was performed by light transmittance aggregometry in platelet-rich plasma (PRP), with platelet-poor plasma (PPP) as reference, and ADP 5 µM as agonist. Kaolin-activated thrombelastography (TEG) was performed in citrate PPP. PRP after aggregation was centrifuged and plasma supernatant (PSN) collected. FXIIIa was measured in PPP and PSN. Platelet aggregation after stimulation with ADP 5 µM resulted in 24% additional FXIIIa release in PSN as compared to PPP (99.3 ± 27 vs. 80.3 ± 24%, p < 0.0001). FXIIIa concentration in PSN correlated with maximal plasma clot strength (TEG-G) (r = 0.48, p < 0.0001), but not in PPP (r = 0.15, p = 0.14). Increasing quartiles of platelet-derived FXIIIa were associated with incrementally higher TEG-G (p = 0.012). FXIIIa release was similar between clopidogrel responders and non-responders (p = 0.18). In summary, platelets treated with aspirin and clopidogrel release a significant amount of FXIIIa upon aggregation by ADP. Platelet-derived FXIIIa may contribute to differences in plasma TEG-G, and thus, in part, provide a mechanistic explanation for high clot strength observed as a consequence of platelet activation. Variability in clopidogrel response does not significantly influence FXIIIa release from platelets.

  18. Complement Activation Alters Platelet Function

    DTIC Science & Technology

    2015-12-01

    haemostatic and coagulation properties of platelets. 15. SUBJECT TERMS Platelets, Complement, Trauma, Tissue Damage 16. SECURITY CLASSIFICATION... coagulation , there is mounting evidence that they may also be important in the development and progression of inflammatory processes (Coppinger et al...receptor-ligand interactions and/or through exposure to cytokines including IL-6, other acute-phase reactants, and pro- coagulant factors such as thrombin

  19. Effect of serotonin on platelet function in cocaine exposed blood

    PubMed Central

    Ziu, Endrit; Hadden, Coedy; Li, Yicong; Lowery, Curtis Lee; Singh, Preeti; Ucer, Serra S.; Mercado, Charles P.; Gu, Howard H.; Kilic, Fusun

    2014-01-01

    5-hydroxytryptamine (5-HT) reuptake inhibitors counteract the pro-thrombotic effect of elevated plasma 5-HT by down-regulating the 5-HT uptake rates of platelets. Cocaine also down-regulates the platelet 5-HT uptake rates but in contrast, the platelets of cocaine-injected mice show a much higher aggregation rate than the platelets of control mice. To examine the involvement of plasma 5-HT in cocaine-mediated platelet aggregation, we studied the function of platelets isolated from wild-type and transgenic, peripheral 5-HT knock-out (TPH1-KO) mice, and cocaine-insensitive dopamine transporter knock in (DAT-KI) mice. In cocaine-injected mice compared to the control mice, the plasma 5-HT level as well as the surface level of P-selectin was elevated; in vitro platelet aggregation in the presence of type I fibrillar collagen was enhanced. However, cocaine injection lowered the 5-HT uptake rates of platelets and increased the plasma 5-HT levels of the DAT-KI mice but did not change their platelets aggregation rates further which are already hyper-reactive. Furthermore, the in vitro studies supporting these in vivo findings suggest that cocaine mimics the effect of elevated plasma 5-HT level on platelets and in 5-HT receptor- and transporter-dependent pathways in a two-step process propagates platelet aggregation by an additive effect of 5-HT and nonserotonergic catecholamine. PMID:25091505

  20. Complement Activation on Platelets Correlates with a Decrease in Circulating Immature Platelets in Patients with Immune Thrombocytopenic Purpura

    PubMed Central

    Peerschke, Ellinor I.B.; Andemariam, Biree; Yin, Wei; Bussel, James B.

    2010-01-01

    The role of the complement system in immune thrombocytopenic purpura (ITP) is not well defined. We examined plasma from 79 patients with ITP, 50 healthy volunteers, and 25 patients with non-immune mediated thrombocytopenia, to investigate their complement activation/fixation capacity (CAC) on immobilized heterologous platelets. Enhanced CAC was found in 46 plasma samples (59%) from patients with ITP, but no samples from patients with non-immune mediated thrombocytopenia. Plasma from healthy volunteers was used for comparison. In patients with ITP, an enhanced plasma CAC was associated with a decreased circulating absolute immature platelet fraction (A-IPF) (<15 × 109/L) (p = 0.027) and thrombocytopenia (platelet count less than 100K/μl) (p= 0.024). The positive predictive value of an enhanced CAC for a low A-IPF was 93%, with a specificity of 77%. The specificity and positive predictive values increased to 100% when plasma CAC was defined strictly by enhanced C1q and/or C4d deposition on test platelets. Although no statistically significant correlation emerged between CAC and response to different pharmacologic therapies, an enhanced response to splenectomy was noted (p <0.063). Thus, complement fixation may contribute to the thrombocytopenia of ITP by enhancing clearance of opsonized platelets from the circulation, and/or directly damaging platelets and megakaryocytes. PMID:19925495

  1. PLATELET ADHESION TO POLYURETHANE UREA UNDER PULSATILE FLOW CONDITIONS

    PubMed Central

    Navitsky, Michael A.; Taylor, Joshua O.; Smith, Alexander B.; Slattery, Margaret J.; Deutsch, Steven; Siedlecki, Christopher A.; Manning, Keefe B.

    2014-01-01

    Platelet adhesion to a polyurethane urea surface is a precursor to thrombus formation within blood-contacting cardiovascular devices, and platelets have been found to adhere strongly to polyurethane surfaces below a shear rate of approximately 500 s−1. The aim of the current work is to determine platelet adhesion properties to the polyurethane urea surface as a function of time varying shear exposure. A rotating disk system is used to study the influence of steady and pulsatile flow conditions (e.g. cardiac inflow and sawtooth waveforms) for platelet adhesion to the biomaterial surface. All experiments retain the same root mean square angular rotation velocity (29.63 rad/s) and waveform period. The disk is rotated in platelet rich bovine plasma for two hours with adhesion quantified by confocal microscopy measurements of immunofluorescently labeled bovine platelets. Platelet adhesion under pulsating flow is found to exponentially decay with increasing shear rate. Adhesion levels are found to depend upon peak platelet flux and shear rate regardless of rotational waveform. In combination with flow measurements, these results may be useful for predicting regions susceptible to thrombus formation within ventricular assist devices. PMID:24721222

  2. Effects of protopine on blood platelet aggregation. III. Effect of protopine on the metabolic system of arachidonic acid in platelets.

    PubMed

    Shiomoto, H; Matsuda, H; Kubo, M

    1991-02-01

    The mode of action of protopine on blood platelet aggregation was investigated in the metabolic system of arachidonic acid and in liberation of platelet activating factor using in vitro experimental models. Protopine inhibited the releases of arachidonic acid and platelet activating factor from platelet membrane phospholipids. Protopine also inhibited the conversion of prostaglandin G2 to thromboxane A2, as well as carboxyheptyl imidazole, a thromboxane synthetase inhibitor. These results indicated that protopine functions both as a phospholipase inhibitor and a thromboxane synthetase inhibitor. It is expected that protopine can be applied for treatment of thrombosis as an antiplatelet drug.

  3. Evaluation of mean platelet volume in localized scleroderma.

    PubMed

    Bahali, Anil Gulsel; Su, Ozlem; Emiroglu, Nazan; Cengiz, Fatma Pelin; Kaya, Mehmet Onur; Onsun, Nahide

    2017-01-01

    Localized scleroderma is a chronic inflammatory skin disease characterized by sclerosis of the dermis and subcutaneous tissue. Platelets play an important role in inflammation. Following activation, platelets rapidly release numerous mediators and cytokines, which contribute to inflammation. To evaluate whether there was any relation between localized scleroderma and platelet parameters. Forty-one patients with localized scleroderma were enrolled in the study. The control group consisted of 30 healthy subjects. The mean platelet volume level in the patient group was 9.9 ± 1.3 fl and in the control group was 7.6 ± 1.1 fl. This difference was statistically significant (p< 0.001). The plateletcrit values are minimally higher in the patient group as compared to the control group. It was statistically significant (p<0.001). There was no significant difference in the platelet counts between the two groups (p= 0.560) In the patient group, there was no significant relation between the mean platelet volume levels and clinical signs of disease (p=0.09). However, plateletcrit values are higher in generalized than localized forms of disease (p=0.01). The limited number of patients and the retrospective nature of the study were our limitations. This study suggests that platelets might play a role in the pathogenesis of scleroderma. Platelet parameters may be used as markers for evaluating disease severity and inflammatory processes. Thus, there is a need for more detailed and prospective studies.

  4. Thrombocytopenia and Platelet Dysfunction in Acute Tropical Infectious Diseases.

    PubMed

    Hapsari Putri, Indri; Tunjungputri, Rahajeng N; De Groot, Philip G; van der Ven, Andre J; de Mast, Quirijn

    2018-06-18

    Thrombocytopenia is a well-known manifestation of acute tropical infectious diseases. The role of platelets in infections has received much attention recently because of their emerging activities in modulation of inflammatory responses, host defense, and vascular integrity. However, while many studies have addressed thrombocytopenia in tropical infections, abnormalities in platelet function have been largely overlooked. This is an important research gap, as platelet dysfunction may contribute to the bleeding tendency that characterizes some tropical infections. The development of novel platelet function assays that can be used in thrombocytopenic conditions (e.g., flow cytometry assays) has contributed to important new insights in recent years. In this review, the importance of platelets in tropical infections is discussed with special emphasis on the underlying mechanisms and consequences of thrombocytopenia and platelet dysfunction in these infections. Special attention is paid to malaria, a disease characterized by microvascular obstruction in which bleeding is rare, and to infections in which bleeding is common, such as dengue, other viral hemorrhagic fevers, and the bacterial infection leptospirosis. Given the importance of platelet function abnormalities in these infections, the development of affordable assays for monitoring of platelet function in low-resource countries, as well as pharmacologic interventions to prevent or reverse platelet function abnormalities, might improve clinical care and the prognosis of these infections. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  5. Dose of Prophylactic Platelet Transfusions and Prevention of Hemorrhage

    PubMed Central

    Slichter, Sherrill J.; Kaufman, Richard M.; Assmann, Susan F.; McCullough, Jeffrey; Triulzi, Darrell J.; Strauss, Ronald G.; Gernsheimer, Terry B.; Ness, Paul M.; Brecher, Mark E.; Josephson, Cassandra D.; Konkle, Barbara A.; Woodson, Robert D.; Ortel, Thomas L.; Hillyer, Christopher D.; Skerrett, Donna L.; McCrae, Keith R.; Sloan, Steven R.; Uhl, Lynne; George, James N.; Aquino, Victor M.; Manno, Catherine S.; McFarland, Janice G.; Hess, John R.; Leissinger, Cindy; Granger, Suzanne

    2010-01-01

    BACKGROUND We conducted a trial of prophylactic platelet transfusions to evaluate the effect of platelet dose on bleeding in patients with hypoproliferative thrombocytopenia. METHODS We randomly assigned hospitalized patients undergoing hematopoietic stem-cell transplantation or chemotherapy for hematologic cancers or solid tumors to receive prophylactic platelet transfusions at a low dose, a medium dose, or a high dose (1.1×1011, 2.2×1011, or 4.4×1011 platelets per square meter of body-surface area, respectively), when morning platelet counts were 10,000 per cubic millimeter or lower. Clinical signs of bleeding were assessed daily. The primary end point was bleeding of grade 2 or higher (as defined on the basis of World Health Organization criteria). RESULTS In the 1272 patients who received at least one platelet transfusion, the primary end point was observed in 71%, 69%, and 70% of the patients in the low-dose group, the medium-dose group, and the high-dose group, respectively (differences were not significant). The incidences of higher grades of bleeding, and other adverse events, were similar among the three groups. The median number of platelets transfused was significantly lower in the low-dose group (9.25×1011) than in the medium-dose group (11.25×1011) or the high-dose group (19.63×1011) (P = 0.002 for low vs. medium, P<0.001 for high vs. low and high vs. medium), but the median number of platelet transfusions given was significantly higher in the low-dose group (five, vs. three in the medium-dose and three in the high-dose group; P<0.001 for low vs. medium and low vs. high). Bleeding occurred on 25% of the study days on which morning platelet counts were 5000 per cubic millimeter or lower, as compared with 17% of study days on which platelet counts were 6000 to 80,000 per cubic millimeter (P<0.001). CONCLUSIONS Low doses of platelets administered as a prophylactic transfusion led to a decreased number of platelets transfused per patient but an

  6. Platelet-rich fibrin: the benefits.

    PubMed

    Kumar, Yuvika Raj; Mohanty, Sujata; Verma, Mahesh; Kaur, Raunaq Reet; Bhatia, Priyanka; Kumar, Varun Raj; Chaudhary, Zainab

    2016-01-01

    Current published data presents confusing results about the effects of platelet-rich fibrin on bone, and there is a need for studies that throw light on its effect. Our main objective therefore was to evaluate (by fractal analysis) osseous regeneration in extraction sockets with and without platelet-rich fibrin in a study with a substantial sample and a reliable technique to calibrate its effects on bone cells. We also assessed the soft tissue response. Thirty-four patients had their bilaterally impacted third molars (68 surgical sites) extracted in this split-mouth study, following which platelet-rich fibrin was placed in one of the sockets. Patients were followed up clinically and radiographically, and a pain score and fractal analysis were used to evaluate healing of soft tissue and bone, respectively. We conclude that platelet-rich fibrin improves healing of both soft and hard tissues. Although osseous healing did not differ significantly between the groups, healing of soft tissue as judged by the pain score was significantly better in the experimental group. Copyright © 2015 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  7. Expression of platelet-derived growth factor and its receptors in proliferative disorders of fibroblastic origin.

    PubMed

    Smits, A; Funa, K; Vassbotn, F S; Beausang-Linder, M; af Ekenstam, F; Heldin, C H; Westermark, B; Nistér, M

    1992-03-01

    Platelet-derived growth factor (PDGF) is known to stimulate the proliferation of connective tissue-derived cells in vitro. Less is known about its functions in vivo, and the role of PDGF in the development of human tumors has not been clarified. The authors have investigated the occurrence of PDGF and PDGF receptors in a series of proliferative disorders of fibroblastic origin using immunohistochemical and in situ hybridization techniques. High expression of PDGF beta-receptor mRNA and protein was found in the malignant tumors, and also in some benign lesions, such as dermatofibroma. In all these cases, benign as well as malignant, the PDGF B-chain mRNA, and less clearly, the PDGF A-chain mRNA, were coexpressed with the beta-receptor. In contrast, high expression of PDGF alpha-receptor mRNA was only found in fully malignant lesions, i.e., malignant fibrous histiocytoma. These data indicate that an autocrine growth stimulation via the PDGF beta-receptor could occur in an early phase of tumorigenesis, and may be a necessary but insufficient event for the progression into fully malignant human connective tissue lesions.

  8. Expression of platelet-derived growth factor and its receptors in proliferative disorders of fibroblastic origin.

    PubMed Central

    Smits, A.; Funa, K.; Vassbotn, F. S.; Beausang-Linder, M.; af Ekenstam, F.; Heldin, C. H.; Westermark, B.; Nistér, M.

    1992-01-01

    Platelet-derived growth factor (PDGF) is known to stimulate the proliferation of connective tissue-derived cells in vitro. Less is known about its functions in vivo, and the role of PDGF in the development of human tumors has not been clarified. The authors have investigated the occurrence of PDGF and PDGF receptors in a series of proliferative disorders of fibroblastic origin using immunohistochemical and in situ hybridization techniques. High expression of PDGF beta-receptor mRNA and protein was found in the malignant tumors, and also in some benign lesions, such as dermatofibroma. In all these cases, benign as well as malignant, the PDGF B-chain mRNA, and less clearly, the PDGF A-chain mRNA, were coexpressed with the beta-receptor. In contrast, high expression of PDGF alpha-receptor mRNA was only found in fully malignant lesions, i.e., malignant fibrous histiocytoma. These data indicate that an autocrine growth stimulation via the PDGF beta-receptor could occur in an early phase of tumorigenesis, and may be a necessary but insufficient event for the progression into fully malignant human connective tissue lesions. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:1372158

  9. Platelet Donation

    MedlinePlus

    ... Friday and when we left the hospital Friday night! I just can’t put it in to words!” Megan Stoy describing how platelets help her daughter Olivia who is fighting cancer "The truly frustrating thing about cancer, is that ...

  10. Passive participation of fixed platelets in aggregation facilitated by covalently bound fibrinogen.

    PubMed

    Agam, G; Livne, A

    1983-01-01

    The role of fibrinogen in interplatelet recognition during aggregation was examined by combining two cell types: fresh platelets (in limiting density) activated by thrombin or A23187, and formaldehyde-fixed platelets, bearing cross-linked fibrinogen. The fixed platelets did not aggregate by themselves, nor with resting platelets, but were capable of interacting with activated platelets and of participating passively in aggregation. The participation, expressed by enhanced aggregation, was assayed by the conventional turbidometric traces and by cosedimentation of fixed 3H-platelets with aggregates of fresh platelets. Platelet suspensions, prepared without special means to avert spontaneous activation, retained plasma fibrinogen to the extent of 50 micrograms/ml of a suspension containing 10(8) platelets, and the derived fixed platelets participated in aggregation, independently of added fibrinogen. The capability of such fixed platelets to participate in aggregation was sensitive to proteolytic digestion and to massive acetylation. When platelet separation was aided by apyrase or aspirin, PGE1 and gel filtration, the residual plasma fibrinogen was limited to 0.4 micrograms/ml of 10(8) platelet suspension. The derived fixed platelets were incapable of participating in aggregation unless fibrinogen was added prior to fixation. The affixed fibrinogen could not be replaced by soluble fibrinogen or affixed albumin. It is concluded that fibrinogen, which binds to platelets upon activation or is linked to them covalently, is a recognition site for platelet-platelet interaction during aggregation.

  11. N-acetylcysteine potentiates platelet inhibition by endothelium-derived relaxing factor.

    PubMed

    Stamler, J; Mendelsohn, M E; Amarante, P; Smick, D; Andon, N; Davies, P F; Cooke, J P; Loscalzo, J

    1989-09-01

    Recent evidence suggests that endothelium-derived relaxing factor exhibits properties of nitric oxide. Like nitric oxide, it inhibits platelet function and mediates its effects by elevating intracellular cyclic GMP. In this study we have investigated the role of reduced thiol in the mechanism of action of endothelium-derived relaxing factor on platelets. Bovine aortic endothelial cells were grown on microcarrier beads and pretreated with aspirin before use. Endothelial cells stimulated with bradykinin or exposed to stirred medium expressed a dose-dependent inhibition of platelet aggregation that was potentiated by the reduced thiol, N-acetylcysteine. Endothelial cell-mediated platelet inhibition was attenuated by methylene blue. Inhibition of platelet aggregation by endothelial cells was associated with a rise in platelet intracellular cyclic GMP, an effect that was enhanced by N-acetylcysteine. These data show that 1) the reduced thiol N-acetylcysteine potentiates platelet inhibition by endothelium-derived relaxing factor and 2) this effect is associated with increasing intracellular platelet cyclic GMP levels.

  12. Inhibitory effects of ethyl pyruvate on platelet aggregation and phosphatidylserine exposure.

    PubMed

    Li, Wenjin; Yang, Xinyu; Peng, Minyuan; Li, Can; Mu, Guangfu; Chen, Fangping

    2017-06-03

    Ethyl pyruvate (EP) is a stable lipophilic pyruvate derivative. Studies demonstrated that EP shows potent anti-oxidation, anti-inflammatory and anti-coagulant effects. Inflammation and coagulation are closely interacted with platelet activation. However, it is unclear whether EP has anti-platelet effects. Therefore, we investigated the anti-platelet effect of EP in this study in vitro. We found that EP inhibited agonists induced platelets aggregation, ATP release and adhesion to collagen. Flow cytometric analysis revealed that EP inhibited agonist induced platelets PAC-1 binding, as well as P-selectin and CD40L expression. The underlying mechanism of action may involve the inhibition of platelet PI3K/Akt and Protein Kinase C (PKC) signaling pathways. Additionally, EP dose dependently inhibited platelet PS exposure induced by high concentration thrombin. Lactate dehydrogenase (LDH) activity assay and mice platelet count implied that EP may have no toxic effect on platelets. Therefore, we are the first to report that EP has potent anti-platelet activity and attenuates platelet PS exposure in vitro, suggesting that the inhibitory effects of EP on platelets may also play important roles in improvement of inflammation and coagulation disorder in related animal models. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Casual chocolate consumption and inhibition of platelet function.

    PubMed

    Bordeaux, Bryan; Yanek, Lisa R; Moy, Taryn F; White, Linda W; Becker, Lewis C; Faraday, Nauder; Becker, Diane M

    2007-01-01

    Observational studies have associated reduced cardiovascular mortality with chocolate consumption. Feeding studies of high-dose, flavanol-rich chocolate show antiplatelet effects, but the effect of casual chocolate consumption on platelet function is unknown. Healthy adults (N=1535) were proscribed from consuming foods affecting platelet function, including chocolate, for 48 hours and completed a 24-hour dietary recall before ex vivo platelet testing with the Platelet Function Analyzer (PFA)-100 (Dade Behring, Inc, Deerfield, IL) test and in vivo testing with urinary 11-dehydro thromboxane B2 (Tx-M) measurements. Some participants (n=141) reported ignoring the prohibition of consuming chocolate before platelet testing. Despite having similar baseline characteristics, chocolate consumers had longer PFA closure times (130 vs 123 seconds, P=.005) and decreased Tx-M levels (175 vs 290 ng/mol creatinine, P=.03). Chocolate remained a significant independent predictor of both ex vivo and in vivo platelet function testing after adjusting for confounders. The authors concluded that even consuming modest amounts of commercial chocolate has important antiplatelet effects.

  14. R1: Platelets and Megakaryocytes contain functional NF-κB

    PubMed Central

    Spinelli, Sherry L.; Casey, Ann E.; Pollock, Stephen J.; Gertz, Jacqueline M.; McMillan, David H.; Narasipura, Srinivasa D.; Mody, Nipa A.; King, Michael R.; Maggirwar, Sanjay B.; Francis, Charles W.; Taubman, Mark B.; Blumberg, Neil; Phipps, Richard P.

    2010-01-01

    The Nuclear Factor (NF)-κB transcription factor family is well-known for their role in eliciting inflammation and promoting cell survival. We discovered that human megakaryocytes and platelets express the majority of NF-κB family members including the regulatory Inhibitor (I)-κB and Inhibitor Kappa Kinase (IKK) molecules. Objective Investigate the presence and role of NF-κB proteins in megakaryocytes and platelets. Methods and Results Anucleate platelets exposed to NF-κB inhibitors demonstrated impaired fundamental functions involved in repairing vascular injury and thrombus formation. Specifically, NF-κB inhibition diminished lamellapodia formation, decreased clot retraction times and reduced thrombus stability. Moreover, inhibition of I-κB-α phosphorylation (BAY-11-7082) reverts fully spread platelets back to a spheroid morphology. Addition of recombinant IKK-β or I-κB-α protein to BAY inhibitor-treated platelets partially restore platelet spreading in I-κB-α inhibited platelets, and addition of active IKK-β increased endogenous I-κB-α phosphorylation levels. Conclusions These novel findings support a crucial and non-classical role for the NF-κB family in modulating platelet function and reveal that platelets are sensitive to NF-κB inhibitors. As NF-κB inhibitors are being developed as anti-inflammatory and anti-cancer agents, they may have unintended effects on platelets. Based on these data, NF-κB is also identified as a new target to dampen unwanted platelet activation. PMID:20042710

  15. Platelet-Rich Plasma Peptides: Key for Regeneration

    PubMed Central

    Sánchez-González, Dolores Javier; Méndez-Bolaina, Enrique; Trejo-Bahena, Nayeli Isabel

    2012-01-01

    Platelet-derived Growth Factors (GFs) are biologically active peptides that enhance tissue repair mechanisms such as angiogenesis, extracellular matrix remodeling, and cellular effects as stem cells recruitment, chemotaxis, cell proliferation, and differentiation. Platelet-rich plasma (PRP) is used in a variety of clinical applications, based on the premise that higher GF content should promote better healing. Platelet derivatives represent a promising therapeutic modality, offering opportunities for treatment of wounds, ulcers, soft-tissue injuries, and various other applications in cell therapy. PRP can be combined with cell-based therapies such as adipose-derived stem cells, regenerative cell therapy, and transfer factors therapy. This paper describes the biological background of the platelet-derived substances and their potential use in regenerative medicine. PMID:22518192

  16. Dose response of surfactants to attenuate gas embolism related platelet aggregation

    NASA Astrophysics Data System (ADS)

    Eckmann, David M.; Eckmann, Yonaton Y.; Tomczyk, Nancy

    2014-03-01

    Intravascular gas embolism promotes blood clot formation, cellular activation, and adhesion events, particularly with platelets. Populating the interface with surfactants is a chemical-based intervention to reduce injury from gas embolism. We studied platelet activation and platelet aggregation, prominent adverse responses to blood contact with bubbles. We examined dose-response relationships for two chemically distinct surfactants to attenuate the rise in platelet function stimulated by exposure to microbubbles. Significant reduction in platelet aggregation and platelet activation occurred with increasing concentration of the surfactants, indicating presence of a saturable system. A population balance model for platelet aggregation in the presence of embolism bubbles and surfactants was developed. Monte Carlo simulations for platelet aggregation were performed. Results agree qualitatively with experimental findings. Surfactant dose-dependent reductions in platelet activation and aggregation indicate inhibition of the gas/liquid interface's ability to stimulate cellular activation mechanically.

  17. Evaluation of two platelet-rich plasma processing methods and two platelet-activation techniques for use in llamas and alpacas.

    PubMed

    Semevolos, Stacy A; Youngblood, Cori D; Grissom, Stephanie K; Gorman, M Elena; Larson, Maureen K

    2016-11-01

    OBJECTIVE To evaluate 2 processing methods (commercial kit vs conical tube centrifugation) for preparing platelet rich plasma (PRP) for use in llamas and alpacas. SAMPLES Blood samples (30 mL each) aseptically collected from 6 healthy llamas and 6 healthy alpacas. PROCEDURES PRP was prepared from blood samples by use of a commercial kit and by double-step conical tube centrifugation. A CBC was performed for blood and PRP samples. Platelets in PRP samples were activated by means of a freeze-thaw method with or without 23mM CaCl 2 , and concentrations of platelet-derived growth factor-BB and transforming growth factor-β 1 were measured. Values were compared between processing methods and camelid species. RESULTS Blood CBC values for llamas and alpacas were similar. The commercial kit yielded a significantly greater degree of platelet enrichment (mean increase, 8.5 fold vs 2.8 fold) and WBC enrichment (mean increase, 3.7 fold vs 1.9 fold) than did conical tube centrifugation. Llamas had a significantly greater degree of platelet enrichment than alpacas by either processing method. No difference in WBC enrichment was identified between species. Concentrations of both growth factors were significantly greater in PRP samples obtained by use of the commercial kit versus those obtained by conical tube centrifugation. CONCLUSIONS AND CLINICAL RELEVANCE For blood samples from camelids, the commercial kit yielded a PRP product with a higher platelet and WBC concentration than achieved by conical tube centrifugation. Optimal PRP platelet and WBC concentrations for various applications need to be determined for llamas and alpacas.

  18. Platelet size and density affect shear-induced thrombus formation in tortuous arterioles

    NASA Astrophysics Data System (ADS)

    Chesnutt, Jennifer K. W.; Han, Hai-Chao

    2013-10-01

    Thrombosis accounts for 80% of deaths in patients with diabetes mellitus. Diabetic patients demonstrate tortuous microvessels and larger than normal platelets. Large platelets are associated with increased platelet activation and thrombosis, but the physical effects of large platelets in the microscale processes of thrombus formation are not clear. Therefore, the objective of this study was to determine the physical effects of mean platelet volume (MPV), mean platelet density (MPD) and vessel tortuosity on platelet activation and thrombus formation in tortuous arterioles. A computational model of the transport, shear-induced activation, collision, adhesion and aggregation of individual platelets was used to simulate platelet interactions and thrombus formation in tortuous arterioles. Our results showed that an increase in MPV resulted in a larger number of activated platelets, though MPD and level of tortuosity made little difference on platelet activation. Platelets with normal MPD yielded the lowest amount of mural thrombus. With platelets of normal MPD, the amount of mural thrombus decreased with increasing level of tortuosity but did not have a simple monotonic relationship with MPV. The physical mechanisms associated with MPV, MPD and arteriole tortuosity play important roles in platelet activation and thrombus formation.

  19. Platelet-released growth factors can accelerate tenocyte proliferation and activate the anti-oxidant response element.

    PubMed

    Tohidnezhad, M; Varoga, D; Wruck, C J; Brandenburg, L O; Seekamp, A; Shakibaei, M; Sönmez, T T; Pufe, Thomas; Lippross, S

    2011-05-01

    Little is know about the pathophysiology of acute and degenerative tendon injuries. Although most lesions are uncomplicated, treatment is long and unsatisfactory in a considerable number of cases. Besides the common growth factors that were shown to be relevant for tendon integrity more recently protection against oxidative stress was shown to promote tendon healing. To improve tendon regeneration, many have advocated the use of platelet-rich plasma (PRP), a thrombocyte concentrate that can serve as an autologous source of growth factors. In this study, we investigated the effect of platelet-released growth factors (PRGF) on tenocytes. Tenocytes were isolated from the Achilles tendon of postnatal rats. Tenocyte cell cultures were stimulated with PRGF. We used a CyQuant assay and WST assay to analyse tendon cell growth and viability in different concentrations of PRGF. Migration and proliferation of cells grown in PRGF were assessed by a scratch test. A dual-luciferase assay was used to demonstrate the activation of the anti-oxidant response element (ARE) in tenocytes. A positive effect of PRGF could be shown on tendon cell growth and migratory capacity. PRGF activated the Nrf2-ARE pathway in a dose-dependent manner. Here, we provide evidence of a biological effect of PRGF on tenocytes by the promotion of tenocyte growth and activation of the Nrf2-ARE pathway. This is a novel aspect of the action of platelet concentrates on tendon growth.

  20. The influence of Rubus idaeus and Rubus caesius leaf extracts on platelet aggregation in whole blood. Cross-talk of platelets and neutrophils.

    PubMed

    Dudzinska, Dominika; Bednarska, Katarzyna; Boncler, Magdalena; Luzak, Boguslawa; Watala, Cezary

    2016-07-01

    Recently, polyphenols have gained attention as potential natural cardioprotective therapeutics, due to their antiplatelet, anti-inflammatory and anticoagulant activity. Species belonging to the genus Rubus sp. have been reported to be a source of polyphenolic compounds with antioxidative proprieties and beneficial biological activities. This study investigates the effects of leaf extracts obtained from red raspberry (Rubus idaeus L.) and European dewberry (Rubus caesius L.) on the reactivity of blood platelets. In ADP-stimulated blood, raspberry and dewberry extracts (15 µg/ml) markedly decreased platelet surface membrane expression of activated GPIIbIIIa receptor by 16% and 21%, respectively (P < 0.01) and significantly inhibited platelet aggregation (by 31-41% for raspberry and by 38-55% for dewberry, P < 0.01). In platelet-rich plasma (PRP), the extracts had no effect on ADP-induced platelet aggregation. The effectiveness of the extracts in whole blood and the lack of their activity in PRP indicate that leukocytes are likely to participate in the platelet response to the extracts. Our experiments show that the extracts significantly reduced the amount of free radicals released by activated neutrophils in whole blood (P < 0.001), as well as in suspensions of isolated neutrophils (P < 0.05). Moreover, the reduced number of neutrophils leads to the decreased efficiency of the extracts in the inhibition of platelet aggregation. In summary, our findings show that the raspberry and dewberry leaf extracts considerably modulated blood platelet reactivity in whole blood: they influenced blood platelet aggregation, possibly via the modulation of the redox status dependent on the oxidative activity of neutrophils.