The Impact of Stress on Tumor Growth; the Significance of Peripheral Corticotropin Releasing Factor

DTIC Science & Technology

2009-05-01

peripheral CRF on breast cancer . Aim of our studies was to determine the impact of peripheral CRF on breast tumor growth and propose a novel potential... breast cancer growth and metastasis. 15. SUBJECT TERMS Stress, Corticotropin Releasing Factor, Wnt, 4T1 mammary epithelial cells 16. SECURITY...13 4 Introduction Aim of the grant proposal was to investigate the role of peripheral CRF on breast cancer cell growth and

Acoustically-Responsive Scaffolds: Control of Growth Factor Release for Tissue Regeneration Using Ultrasound

NASA Astrophysics Data System (ADS)

Moncion, Alexander

Administration of exogenous growth factors (GFs) is a proposed method of stimulating tissue regeneration. Conventional administration routes, such as at-site or systemic injections, have yielded problems with efficacy and/or safety, thus hindering the translation of GF-based regenerative techniques. Hydrogel scaffolds are commonly used as biocompatible delivery vehicles for GFs. Yet hydrogels do not afford spatial or temporal control of GF release - two critical parameters for tissue regeneration. Controlled delivery of GFs is critical for angiogenesis, which is a crucial process in tissue engineering that provides oxygen and nutrients to cells within an implanted hydrogel scaffold. Angiogenesis requires multiple GFs that are presented with distinct spatial and temporal profiles. Thus, controlled release of GFs with spatiotemporal modulation would significantly improve tissue regeneration by recapitulating endogenous GF presentation. In order to achieve this goal, we have developed acoustically-responsive scaffolds (ARSs), which are fibrin hydrogels doped with sonosensitive perfluorocarbon (PFC) emulsions capable of encapsulating various payloads. Focused, mega-Hertz range, ultrasound (US) can modulate the release of a payload non-invasively and in an on-demand manner from ARSs via physical mechanisms termed acoustic droplet vaporization (ADV) and inertial cavitation (IC). This work presents the relationship between the ADV/IC thresholds and various US and hydrogel parameters. These physical mechanisms were used for the controlled release of fluorescent dextran in vitro and in vivo to determine the ARS and US parameters that yielded optimal payload release. The optimal ARS and US parameters were used to demonstrate the controlled release of basic fibroblast growth factor from an in vivo subcutaneous implant model - leading to enhanced angiogenesis and perfusion. Additionally, different acoustic parameters and PFCs were tested and optimized to demonstrate the

Effect of centrifugation time on growth factor and MMP release of an experimental platelet-rich fibrin-type product.

PubMed

Eren, Gülnihal; Gürkan, Ali; Atmaca, Harika; Dönmez, Ayhan; Atilla, Gül

2016-07-01

Platelet-rich fibrin (PRF) has a controlled release of growth factors due to the fibrin matrix structure. Different centrifugation protocols were suggested for PRF preparation. Since the derivation method of PRF can alter its contents, in the present study it is aimed to investigate the cell contents and transforming growth factor beta-1 (TGF-β1), platelet-derived growth factor (PDGF-AB), vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP)-1 and-8 release from experimental PRF-type membranes obtained with different centrifugation times at 400 gravity. Three blood samples were collected from 20 healthy non-smoker volunteers. One tube was used for whole blood analyses. The other two tubes were centrifuged at 400 g for 10 minutes (group A) or 12 minutes (group B). Each experimental PRF-type membrane was placed in Dulbecco's Modified Eagle's Medium (DMEM)and at 1, 24 and 72 hours, TGF-β1, PDGF-AB, VEGF, MMP-1 and -8 release amounts were analysed by enzyme-linked immunosorbent assay (ELISA). The blood cell count of membranes was determined by subtracting plasma supernatant and red blood cell (RBC) mixture from the whole blood cell counts. At 72 hours, the VEGF level of group B was statistically higher than that of group A (p = 0.040). The centrifugation time was not found to influence the release of other growth factors, enzymes and cell counts. Within the limits of the present study, it might be suggested that centrifugation time at a constant gravity has a significant effect on the VEGF levels released from experimental PRF-type membrane. It can be concluded that due to the importance of VEGF in the tissue healing process, membranes obtained at 12-minute centrifugation time may show a superior potential in wound healing.

Gelatin-based hydrogel for vascular endothelial growth factor release in peripheral nerve tissue engineering.

PubMed

Gnavi, S; di Blasio, L; Tonda-Turo, C; Mancardi, A; Primo, L; Ciardelli, G; Gambarotta, G; Geuna, S; Perroteau, I

2017-02-01

Hydrogels are promising materials in regenerative medicine applications, due to their hydrophilicity, biocompatibility and capacity to release drugs and growth factors in a controlled manner. In this study, biocompatible and biodegradable hydrogels based on blends of natural polymers were used in in vitro and ex vivo experiments as a tool for VEGF-controlled release to accelerate the nerve regeneration process. Among different candidates, the angiogenic factor VEGF was selected, since angiogenesis has been long recognized as an important and necessary step during tissue repair. Recent studies have pointed out that VEGF has a beneficial effect on motor neuron survival and Schwann cell vitality and proliferation. Moreover, VEGF administration can sustain and enhance the growth of regenerating peripheral nerve fibres. The hydrogel preparation process was optimized to allow functional incorporation of VEGF, while preventing its degradation and denaturation. VEGF release was quantified through ELISA assay, whereas released VEGF bioactivity was validated in human umbilical vein endothelial cells (HUVECs) and in a Schwann cell line (RT4-D6P2T) by assessing VEGFR-2 and downstream effectors Akt and Erk1/2 phosphorylation. Moreover, dorsal root ganglia explants cultured on VEGF-releasing hydrogels displayed increased neurite outgrowth, providing confirmation that released VEGF maintained its effect, as also confirmed in a tubulogenesis assay. In conclusion, a gelatin-based hydrogel system for bioactive VEGF delivery was developed and characterized for its applicability in neural tissue engineering. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd.

Platelet-Released Growth Factors Induce Differentiation of Primary Keratinocytes

PubMed Central

Tohidnezhad, Mersedeh; Lammel, Justus; Lippross, Sebastian; Behrendt, Peter; Klüter, Tim; Pufe, Thomas; Jahr, Holger; Cremer, Jochen; Rademacher, Franziska; Gläser, Regine; Harder, Jürgen

2017-01-01

Autologous thrombocyte concentrate lysates, for example, platelet-released growth factors, (PRGFs) or their clinically related formulations (e.g., Vivostat PRF®) came recently into the physicians' focus as they revealed promising effects in regenerative and reparative medicine such as the support of healing of chronic wounds. To elucidate the underlying mechanisms, we analyzed the influence of PRGF and Vivostat PRF on human keratinocyte differentiation in vitro and on epidermal differentiation status of skin wounds in vivo. Therefore, we investigated the expression of early (keratin 1 and keratin 10) and late (transglutaminase-1 and involucrin) differentiation markers. PRGF treatment of primary human keratinocytes decreased keratin 1 and keratin 10 gene expression but induced involucrin and transglutaminase-1 gene expression in an epidermal growth factor receptor- (EGFR-) dependent manner. In concordance with these results, microscopic analyses revealed that PRGF-treated human keratinocytes displayed morphological features typical of keratinocytes undergoing terminal differentiation. In vivo treatment of artificial human wounds with Vivostat PRF revealed a significant induction of involucrin and transglutaminase-1 gene expression. Together, our results indicate that PRGF and Vivostat PRF induce terminal differentiation of primary human keratinocytes. This potential mechanism may contribute to the observed beneficial effects in the treatment of hard-to-heal wounds with autologous thrombocyte concentrate lysates in vivo. PMID:28808357

Dual growth factor delivery from biofunctionalized allografts: Sequential VEGF and BMP-2 release to stimulate allograft remodeling.

PubMed

Sharmin, Farzana; McDermott, Casey; Lieberman, Jay; Sanjay, Archana; Khan, Yusuf

2017-05-01

Autografts have been shown to stimulate osteogenesis, osteoclastogenesis, and angiogenesis, and subsequent rapid graft incorporation. Large structural allografts, however, suffer from limited new bone formation and remodeling, both of which are directly associated with clinical failure due to non-unions, late graft fractures, and infections, making it a priority to improve large structural allograft healing. We have previously shown the osteogenic ability of a polymer-coated allograft that delivers bone morphogenetic protein-2 both in vitro and in vivo through both burst release and sustained release kinetics. In this study, we have demonstrated largely sequential delivery of bone morphogenetic protein-2 and vascular endothelial growth factor from the same coated allograft. Release data showed that loading both growth factors onto a polymeric coating with two different techniques resulted in short-term (95% release within 2 weeks) and long-term (95% release within 5 weeks) delivery kinetics. We have also demonstrated how released VEGF, traditionally associated with angiogenesis, can also provide a stimulus for allograft remodeling via resorption. Bone marrow derived mononuclear cells were co-cultured with VEGF released from the coated allograft and showed a statistically significant (p < 0.05) and dose dependent increase in the number of tartrate-resistant acid phosphatase-positive multinucleated osteoclasts. Functionality of these osteoclasts was assessed quantitatively and qualitatively by evaluating resorption pit area from both osteo-assay plates and harvested bone. Data indicated a statistically significant higher resorption area from the cells exposed to VEGF released from the allografts over controls (p < 0.05). These results indicate that by using different loading protocols temporal control can be achieved when delivering multiple growth factors from a polymer-coated allograft. Further, released VEGF can also stimulate osteoclastogenesis that may

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

In vitro effects of 0 to 120 Grays of irradiation on bone viability and release of growth factors.

PubMed

Sawada, Kosaku; Fujioka-Kobayashi, Masako; Kobayashi, Eizaburo; Brömme, Jens O; Schaller, Benoit; Miron, Richard J

2016-07-04

High dose radiation therapy is commonly used in maxillofacial surgeries to treat a number of head and neck tumors. Despite its widespread use, little information is available regarding the effects of irradiation on bone cell viability and release of growth factors following dose-dependent irradiation. Bone samples were collected from porcine mandibular cortical bone and irradiated at doses of 0, 7.5, 15, 30, 60 and 120 Grays. Thereafter, cell viability was quantified, and the release of growth factors including TGFβ1, BMP2, VEGF, IL1β and RANKL were investigated over time. It was observed that at only 7.5Gy of irradiation, over 85 % of cells were non-vital and by 60 Gy, all cells underwent apoptosis. Furthermore, over a 7-fold decrease in VEGF and a 2-fold decrease in TGFβ1 were observed following irradiation at all tested doses. Little change was observed for BMP2 and IL1β whereas RANKL was significantly increased for all irradiated samples. These results demonstrate the pronounced effects of irradiation on bone-cell vitality and subsequent release of growth factors. Interestingly, the largest observed change in gene expression was the 7-fold decrease in VEGF protein following irradiation. Future research aimed at improving our understanding of bone following irradiation is necessary to further improve future clinical treatments.

Red blood cells release factors with growth and survival bioactivities for normal and leukemic T cells.

PubMed

Antunes, Ricardo F; Brandão, Cláudia; Maia, Margarida; Arosa, Fernando A

2011-01-01

Human red blood cells are emerging as a cell type capable to regulate biological processes of neighboring cells. Hereby, we show that human red blood cell conditioned media contains bioactive factors that favor proliferation of normal activated T cells and leukemic Jurkat T cells, and therefore called erythrocyte-derived growth and survival factors. Flow cytometry and electron microscopy in parallel with bioactivity assays revealed that the erythrocyte factors are present in the vesicle-free supernatant, which contains up to 20 different proteins. The erythrocyte factors are thermosensitive and do not contain lipids. Native polyacrylamide gel electrophoresis followed by passive elution and mass spectrometry identification reduced the potential erythrocyte factors to hemoglobin and peroxiredoxin II. Two-dimensional differential gel electrophoresis of the erythrocyte factors revealed the presence of multiple hemoglobin oxy-deoxy states and peroxiredoxin II isoforms differing in their isoelectric point akin to the presence of β-globin chains. Our results show that red blood cells release protein factors with the capacity to sustain T-cell growth and survival. These factors may have an unforeseen role in sustaining malignant cell growth and survival in vivo.

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.

Calcium-Alginate Hydrogel-Encapsulated Fibroblasts Provide Sustained Release of Vascular Endothelial Growth Factor

PubMed Central

Hunt, Nicola C.; Shelton, Richard M.; Henderson, Deborah J.

2013-01-01

Vascularization of engineered or damaged tissues is essential to maintain cell viability and proper tissue function. Revascularization of the left ventricle (LV) of the heart after myocardial infarction is particularly important, since hypoxia can give rise to chronic heart failure due to inappropriate remodeling of the LV after death of cardiomyocytes (CMs). Fibroblasts can express vascular endothelial growth factor (VEGF), which plays a major role in angiogenesis and also acts as a chemoattractant and survival factor for CMs and cardiac progenitors. In this in vitro model study, mouse NIH 3T3 fibroblasts encapsulated in 2% w/v Ca-alginate were shown to remain viable for 150 days. Semiquantitative reverse transcription–polymerase chain reaction and immunohistochemistry demonstrated that over 21 days of encapsulation, fibroblasts continued to express VEGF, while enzyme-linked immunosorbent assay showed that there was sustained release of VEGF from the Ca-alginate during this period. The scaffold degraded gradually over the 21 days, without reduction in volume. Cells released from the Ca-alginate at 7 and 21 days as a result of scaffold degradation were shown to retain viability, to adhere to fibronectin in a normal manner, and continue to express VEGF, demonstrating their potential to further contribute to maintenance of cardiac function after scaffold degradation. This model in vitro study therefore demonstrates that fibroblasts encapsulated in Ca-alginate provide sustained release of VEGF. PMID:23082964

Heparin-binding epidermal growth factor-like growth factor promotes neuroblastoma differentiation.

PubMed

Gaviglio, Angela L; Knelson, Erik H; Blobe, Gerard C

2017-05-01

High-risk neuroblastoma is characterized by undifferentiated neuroblasts and low schwannian stroma content. The tumor stroma contributes to the suppression of tumor growth by releasing soluble factors that promote neuroblast differentiation. Here we identify heparin-binding epidermal growth factor-like growth factor (HBEGF) as a potent prodifferentiating factor in neuroblastoma. HBEGF mRNA expression is decreased in human neuroblastoma tumors compared with benign tumors, with loss correlating with decreased survival. HBEGF protein is expressed only in stromal compartments of human neuroblastoma specimens, with tissue from high-stage disease containing very little stroma or HBEGF expression. In 3 human neuroblastoma cell lines (SK-N-AS, SK-N-BE2, and SH-SY5Y), soluble HBEGF is sufficient to promote neuroblast differentiation and decrease proliferation. Heparan sulfate proteoglycans and heparin derivatives further enhance HBEGF-induced differentiation by forming a complex with the epidermal growth factor receptor, leading to activation of the ERK1/2 and STAT3 pathways and up-regulation of the inhibitor of DNA binding transcription factor. These data support a role for loss of HBEGF in the neuroblastoma tumor microenvironment in neuroblastoma pathogenesis.-Gaviglio, A. L., Knelson, E. H., Blobe, G. C. Heparin-binding epidermal growth factor-like growth factor promotes neuroblastoma differentiation. © FASEB.

Heparin-binding epidermal growth factor-like growth factor promotes neuroblastoma differentiation

PubMed Central

Gaviglio, Angela L.; Knelson, Erik H.; Blobe, Gerard C.

2017-01-01

High-risk neuroblastoma is characterized by undifferentiated neuroblasts and low schwannian stroma content. The tumor stroma contributes to the suppression of tumor growth by releasing soluble factors that promote neuroblast differentiation. Here we identify heparin-binding epidermal growth factor–like growth factor (HBEGF) as a potent prodifferentiating factor in neuroblastoma. HBEGF mRNA expression is decreased in human neuroblastoma tumors compared with benign tumors, with loss correlating with decreased survival. HBEGF protein is expressed only in stromal compartments of human neuroblastoma specimens, with tissue from high-stage disease containing very little stroma or HBEGF expression. In 3 human neuroblastoma cell lines (SK-N-AS, SK-N-BE2, and SH-SY5Y), soluble HBEGF is sufficient to promote neuroblast differentiation and decrease proliferation. Heparan sulfate proteoglycans and heparin derivatives further enhance HBEGF-induced differentiation by forming a complex with the epidermal growth factor receptor, leading to activation of the ERK1/2 and STAT3 pathways and up-regulation of the inhibitor of DNA binding transcription factor. These data support a role for loss of HBEGF in the neuroblastoma tumor microenvironment in neuroblastoma pathogenesis.—Gaviglio, A. L., Knelson, E. H., Blobe, G. C. Heparin-binding epidermal growth factor-like growth factor promotes neuroblastoma differentiation. PMID:28174207

Growth hormone response to growth hormone-releasing peptide-2 in growth hormone-deficient Little mice

PubMed Central

Peroni, Cibele N.; Hayashida, Cesar Y.; Nascimento, Nancy; Longuini, Viviane C.; Toledo, Rodrigo A.; Bartolini, Paolo; Bowers, Cyril Y.; Toledo, Sergio P.A.

2012-01-01

OBJECTIVE: To investigate a possible direct, growth hormone-releasing, hormone-independent action of a growth hormone secretagogue, GHRP-2, in pituitary somatotroph cells in the presence of inactive growth hormone-releasing hormone receptors. MATERIALS AND METHODS: The responses of serum growth hormone to acutely injected growth hormone-releasing P-2 in lit/lit mice, which represent a model of GH deficiency arising from mutated growth hormone-releasing hormone-receptors, were compared to those observed in the heterozygous (lit/+) littermates and wild-type (+/+) C57BL/6J mice. RESULTS: After the administration of 10 mcg of growth hormone-releasing P-2 to lit/lit mice, a growth hormone release of 9.3±1.5 ng/ml was observed compared with 1.04±1.15 ng/ml in controls (p<0.001). In comparison, an intermediate growth hormone release of 34.5±9.7 ng/ml and a higher growth hormone release of 163±46 ng/ml were induced in the lit/+ mice and wild-type mice, respectively. Thus, GHRP-2 stimulated growth hormone in the lit/lit mice, and the release of growth hormone in vivo may be only partially dependent on growth hormone-releasing hormone. Additionally, the plasma leptin and ghrelin levels were evaluated in the lit/lit mice under basal and stimulated conditions. CONCLUSIONS: Here, we have demonstrated that lit/lit mice, which harbor a germline mutation in the Growth hormone-releasing hormone gene, maintain a limited but statistically significant growth hormone elevation after exogenous stimulation with GHRP-2. The present data probably reflect a direct, growth hormone-independent effect on Growth hormone S (ghrelin) stimulation in the remaining pituitary somatotrophs of little mice that is mediated by growth hormone S-R 1a. PMID:22473409

Fluid flow releases fibroblast growth factor-2 from human aortic smooth muscle cells

NASA Technical Reports Server (NTRS)

Rhoads, D. N.; Eskin, S. G.; McIntire, L. V.

2000-01-01

This study tested the hypothesis that fluid shear stress regulates the release of fibroblast growth factor (FGF)-2 from human aortic smooth muscle cells. FGF-2 is a potent mitogen that is involved in the response to vascular injury and is expressed in a wide variety of cell types. FGF-2 is found in the cytoplasm of cells and outside cells, where it associates with extracellular proteoglycans. To test the hypothesis that shear stress regulates FGF-2 release, cells were exposed to flow, and FGF-2 amounts were measured from the conditioned medium, pericellular fraction (extracted by heparin treatment), and cell lysate. Results from the present study show that after 15 minutes of shear stress at 25 dyne/cm(2) in a parallel-plate flow system, a small but significant fraction (17%) of the total FGF-2 was released from human aortic smooth muscle cells. FGF-2 levels in the circulating medium increased 10-fold over medium from static controls (P<0.01). A 50% increase in FGF-2 content versus control (P<0.01) was found in the pericellular fraction (extracted by heparin treatment). Furthermore, a significant decrease in FGF-2 was detected in the cell lysate, indicating that FGF-2 was released from inside the cell. Cell permeability studies with fluorescent dextran were performed to examine whether transient membrane disruption caused FGF-2 release. Flow cytometry detected a 50% increase in mean fluorescence of cells exposed to 25 dyne/cm(2) versus control cells. This indicates that the observed FGF-2 release from human aortic smooth muscle cells is likely due to transient membrane disruption on initiation of flow.

Growth factor release by vesicular phospholipid gels: in-vitro results and application for rotator cuff repair in a rat model.

PubMed

Buchmann, Stefan; Sandmann, Gunther H; Walz, Lars; Reichel, Thomas; Beitzel, Knut; Wexel, Gabriele; Tian, Weiwei; Battmann, Achim; Vogt, Stephan; Winter, Gerhard; Imhoff, Andreas B

2015-04-10

Biological augmentation of rotator cuff repair is of growing interest to improve biomechanical properties and prevent re-tearing. But intraoperative single shot growth factor application appears not sufficient to provide healing support in the physiologic growth factor expression peaks. The purpose of this study was to establish a sustained release of granulocyte-colony stimulating factor (G-CSF) from injectable vesicular phospholipid gels (VPGs) in vitro and to examine biocompatibility and influence on histology and biomechanical behavior of G-CSF loaded VPGs in a chronic supraspinatus tear rat model. G-CSF loaded VPGs were produced by dual asymmetric centrifugation. In vitro the integrity, stability and release rate were analyzed. In vivo supraspinatus tendons of 60 rats were detached and after 3 weeks a transosseous refixation with G-CSF loaded VPGs augmentation (n = 15; control, placebo, 1 and 10 μg G-CSF/d) was performed. 6 weeks postoperatively the healing site was analyzed histologically (n = 9; H&E by modified MOVIN score/Collagen I/III) and biomechanically (n = 6). In vitro testing revealed stable proteins after centrifugation and a continuous G-CSF release of up to 4 weeks. Placebo VPGs showed histologically no negative side effects on the healing process. Histologically in vivo testing demonstrated significant advantages for G-CSF 1 μg/d but not for G-CSF 10 μg/d in Collagen III content (p = 0.035) and a higher Collagen I/III ratio compared to the other groups. Biomechanically G-CSF 1 μg/d revealed a significant higher load to failure ratio (p = 0.020) compared to control but no significant differences in stiffness. By use of VPGs a continuous growth factor release could be obtained in vitro. The in vivo results demonstrate an improvement of immunohistology and biomechanical properties with a low dose G-CSF application via VPG. The VPG itself was well tolerated and had no negative influence on the healing behavior. Due to the favorable properties

Suckling induced insulin-like growth factor-1 (IGF-1) release in mother rats.

PubMed

Lékó, András H; Cservenák, Melinda; Dobolyi, Árpád

2017-12-01

Lactation involves significant neuroendocrine changes. The elevated prolactin (PRL) release from the pituitary, induced markedly by suckling, is the most relevant example. Suckling also causes a significant and rapid elevation in growth hormone (GH) levels. GH is necessary for milk synthesis as milk yield is stopped completely in the absence of PRL and GH, while the absence of PRL alone causes only a 50% reduction. Insulin-like growth factor-1 (IGF-1) plays an important role in the GH axis. GH exerts its effects through IGF-1 in the periphery, for example in the mammary gland. In addition, IGF-1 is responsible for the long-loop feedback control of GH secretion. IGF-1 secretion has not been established yet in mothers. Therefore, in the present study, we investigated the effect of suckling on serum IGF-1 level in rat mothers and correlated it with serum PRL levels. We examined a potential mechanism of the regulation of IGF-1 level during suckling by administering IGF-1 into the lateral ventricle of rat mothers continuously for 12days, or acutely, right before the start of suckling. We described that suckling affected IGF-1 release based on one-way repeated measures ANOVA (F=10.8 and p<0.001) and caused a marked increase of IGF-1 level 30min after the start of suckling (p<0.001). We demonstrated a significant (p<0.05; the correlation coefficient was 0.29) correlation to PRL level during suckling which supports that PRL could induce IGF-1 release. The prolonged central IGF-1 administration diminished the suckling-induced IGF-1 surge (F=9.19 and p<0.001) while the acute treatment did not have any effect compared to artificial cerebrospinal fluid injection, analysed with two-way repeated measures ANOVA. In conclusion, suckling induces IGF-1 release either by elevating PRL or GH. Long-loop feedback via IGF-1 in the GH axis can diminish this action. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of trehalose coating on basic fibroblast growth factor release from tailor-made bone implants.

PubMed

Choi, Sungjin; Lee, Jongil; Igawa, Kazuyo; Suzuki, Shigeki; Mochizuki, Manabu; Nishimura, Ryohei; Chung, Ung-il; Sasaki, Nobuo

2011-12-01

Artificial bone implants are often incorporated with osteoinductive factors to facilitate early bone regeneration. Calcium phosphate, the main component in artificial bone implants, strongly binds these factors, and in a few cases, the incorporated proteins are not released from the implant under conditions of physiological pH, thereby leading to reduction in their osteoinductivity. In this study, we coated tailor-made bone implants with trehalose to facilitate the release of basic fibroblast growth factor (bFGF). In an in vitro study, mouse osteoblastic cells were separately cultured for 48 hr in a medium with a untreated implant (T-), trehalose-coated implant (T+), bFGF-incorporated implant (FT-), and bFGF-incorporated implant with trehalose coating (FT+). In the FT+ group, cell viability was significantly higher than that in the other groups (P<0.05). Scanning electron microscopy (SEM) and X-ray diffraction (XRD) revealed that trehalose effectively covered the surface of the artificial bone implant without affecting the crystallinity or the mechanical strength of the artificial bone implant. These results suggest that coating artificial bone implants with trehalose could limit the binding of bFGF to calcium phosphate.

Inhibition of growth hormone-releasing factor suppresses both sleep and growth hormone secretion in the rat.

PubMed

Obál, F; Payne, L; Kapás, L; Opp, M; Krueger, J M

1991-08-23

To study the possible involvement of hypothalamic growth hormone-releasing factor (GRF) in sleep regulation, a competitive GRF-antagonist, the peptide (N-Ac-Tyr1,D-Arg2)-GRF(1-29)-NH2, was intracerebroventricularly injected into rats (0.003, 0.3, and 14 nmol), and the EEG and brain temperature were recorded for 12 h during the light cycle of the day. Growth hormone (GH) concentrations were determined from plasma samples taken at 20-min intervals for 3 h after 14 nmol GRF-antagonist. The onset of non-rapid eye movement sleep (NREMS) was delayed in response to 0.3 and 14 nmol GRF-antagonist, the duration of NREMS was decreased for one or more hours and after 14 nmol EEG slow wave amplitudes were decreased during NREMS in postinjection hour 1. The high dose of GRF-antagonist also suppressed REMS for 4 h, inhibited GH secretion, and elicited a slight biphasic variation in brain temperature. These findings, together with previous observations indicating a sleep-promoting effect for GRF, support the hypothesis that hypothalamic GRF is involved in sleep regulation and might be responsible for the correlation between NREMS and GH secretion reported in various species.

Experiment K-7-22: Growth Hormone Regulation Synthesis and Secretion in Microgravity. Part 2; Hypothalamic Growth Hormone-Releasing Factor, Somatostatin Immunoreactivity, and Messenger RNA Levels in Microgravity

NASA Technical Reports Server (NTRS)

Sawchenko, P. E.; Arias, C.; Krasnov, I.; Grindeland, R. E.; Vale, W.

1994-01-01

Immunohistochemical analyses of hypothalamic hormones carried out on tissue from rats flown on an earlier flight (Cosmos 1887) suggested preferential effects on hypophysiotropic principles involved in the regulation of growth hormone secretion and synthesis. We found that staining in the median eminence for peptides that provide both stimulatory (growth hormone-releasing factor, or GRF) and inhibitory (somatostatin, SS) influences on growth hormone secretion were depressed in flight animals relative to synchronous controls, while staining for other neuroendocrine peptides, cortocotropin-releasing factor and arginine vasopressin, were similar in these two groups. While this suggests some selective impact of weightlessness on the two principal central nervous system regulators of growth hormone dynamics, the fact that both GRF- and SS-immunoreactivity (IR) appeared affected in the same direction is somewhat problematic, and makes tentative any intimation that effects on CNS control mechanisms may be etiologically significant contributors to the sequelae of reduced growth hormone secretion seen in prolonged space flight. To provide an additional, and more penetrating, analysis we attempted in hypothalamic material harvested from animals flown on Cosmos 2044 to complement immunohistochemical analyses of GRF and SS staining with quantitative, in situ assessments of messenger RNAs encoding the precursors for both these hormones.

Minoxidil Promotes Hair Growth through Stimulation of Growth Factor Release from Adipose-Derived Stem Cells

PubMed Central

Choi, Nahyun; Shin, Soyoung; Song, Sun U.; Sung, Jong-Hyuk

2018-01-01

Minoxidil directly promotes hair growth via the stimulation of dermal papilla (DP) and epithelial cells. Alternatively, there is little evidence for indirect promotion of hair growth via stimulation of adipose-derived stem cells (ASCs). We investigated whether minoxidil stimulates ASCs and if increased growth factor secretion by ASCs facilitates minoxidil-induced hair growth. Telogen-to-anagen induction was examined in mice. Cultured DP cells and vibrissae hair follicle organ cultures were used to further examine the underlying mechanisms. Subcutaneous injection of minoxidil-treated ASCs accelerated telogen-to-anagen transition in mice, and increased hair weight at day 14 post-injection. Minoxidil did not alter ASC proliferation, but increased migration and tube formation. Minoxidil also increased the secretion of growth factors from ASCs, including chemokine (C-X-C motif) ligand 1 (CXCL1), platelet-derived endothelial cell growth factor (PD-ECGF), and platelet-derived growth factor-C (PDGF-C). Minoxidil increased extracellular signal–regulated kinases 1/2 (ERK1/2) phosphorylation, and concomitant upregulation of PD-ECGF and PDGF-C mRNA levels were attenuated by an ERK inhibitor. Subcutaneous injection of CXCL1, PD-ECGF, or PDGF-C enhanced anagen induction in mice, and both CXCL1 and PDGF-C increased hair length in ex vivo organ culture. Treatment with CXCL1, PD-ECGF, or PDGF-C also increased the proliferation index in DP cells. Finally, topical application of CXCL1, PD-ECGF, or PDGF-C with 2% minoxidil enhanced anagen induction when compared to minoxidil alone. Minoxidil stimulates ASC motility and increases paracrine growth factor signaling. Minoxidil-stimulated secretion of growth factors by ASCs may enhance hair growth by promoting DP proliferation. Therefore, minoxidil can be used as an ASC preconditioning agent for hair regeneration. PMID:29495622

Minoxidil Promotes Hair Growth through Stimulation of Growth Factor Release from Adipose-Derived Stem Cells.

PubMed

Choi, Nahyun; Shin, Soyoung; Song, Sun U; Sung, Jong-Hyuk

2018-02-28

Minoxidil directly promotes hair growth via the stimulation of dermal papilla (DP) and epithelial cells. Alternatively, there is little evidence for indirect promotion of hair growth via stimulation of adipose-derived stem cells (ASCs). We investigated whether minoxidil stimulates ASCs and if increased growth factor secretion by ASCs facilitates minoxidil-induced hair growth. Telogen-to-anagen induction was examined in mice. Cultured DP cells and vibrissae hair follicle organ cultures were used to further examine the underlying mechanisms. Subcutaneous injection of minoxidil-treated ASCs accelerated telogen-to-anagen transition in mice, and increased hair weight at day 14 post-injection. Minoxidil did not alter ASC proliferation, but increased migration and tube formation. Minoxidil also increased the secretion of growth factors from ASCs, including chemokine (C-X-C motif) ligand 1 (CXCL1), platelet-derived endothelial cell growth factor (PD-ECGF), and platelet-derived growth factor-C (PDGF-C). Minoxidil increased extracellular signal-regulated kinases 1/2 (ERK1/2) phosphorylation, and concomitant upregulation of PD-ECGF and PDGF-C mRNA levels were attenuated by an ERK inhibitor. Subcutaneous injection of CXCL1, PD-ECGF, or PDGF-C enhanced anagen induction in mice, and both CXCL1 and PDGF-C increased hair length in ex vivo organ culture. Treatment with CXCL1, PD-ECGF, or PDGF-C also increased the proliferation index in DP cells. Finally, topical application of CXCL1, PD-ECGF, or PDGF-C with 2% minoxidil enhanced anagen induction when compared to minoxidil alone. Minoxidil stimulates ASC motility and increases paracrine growth factor signaling. Minoxidil-stimulated secretion of growth factors by ASCs may enhance hair growth by promoting DP proliferation. Therefore, minoxidil can be used as an ASC preconditioning agent for hair regeneration.

The portal-drained viscera release fibroblast growth factor 19 in humans.

PubMed

Koelfat, Kiran V K; Bloemen, Johanne G; Jansen, Peter L M; Dejong, Cornelis H C; Schaap, Frank G; Olde Damink, Steven W M

2016-12-01

Fibroblast growth factor 19 (FGF19) is an ileum-derived endrocrine factor that is produced in response to transepithelial bile salt flux. FGF19 represses bile salt synthesis in the liver. Despite the general assumption that FGF19 signals to the liver via portal blood, no human data are available to support this notion. The aim was to study portal FGF19 levels, and determined bile salt and FGF19 fluxes across visceral organs in humans. Bile salt and FGF19 levels were assessed in arterial, portal, and hepatic venous blood collected from fasted patients who underwent partial liver resection for colorectal liver metastases (n = 30). Fluxes across the portal-drained viscera (PDV), liver, and splanchnic area were calculated. Portal bile salt levels (7.8 [5.0-12.4] μmol/L) were higher than levels in arterial (2.7 [1.7-5.5] μmol/L, P < 0.0001) and hepatic venous blood (3.4 [2.5-6.5] μmol/L, P < 0.0001). Bile salts released by the PDV (+1.2 [+0.7-+2.0] mmol kg -1  h -1 , P < 0.0001) were largely taken up by the liver (-1.0 [-1.8 to -0.4] mmol kg -1  h -1 , P < 0.0001). Portal levels of FGF19 (161 ± 78 pg/mL) were higher than arterial levels (135 ± 65 pg/mL, P = 0.046). A net release of FGF19 by the PDV (+4.0 [+2.1 to +9.9] ng kg -1  h -1 , P < 0.0001) was calculated. There was no significant flux of FGF19 across the liver (-0.2 [-3.7 to +7.4] ng kg -1  h -1 , P = 0.93). In conclusion, FGF19 levels in human portal blood are higher than in arterial blood. FGF19 is released by the portal-drained viscera under fasted steady state conditions. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Interleukin-6 and vascular endothelial growth factor release by renal cell carcinoma cells impedes lymphocyte-dendritic cell cross-talk.

PubMed

Cabillic, F; Bouet-Toussaint, F; Toutirais, O; Rioux-Leclercq, N; Fergelot, P; de la Pintière, C Thomas; Genetet, N; Patard, J-J; Catros-Quemener, V

2006-12-01

Anti-tumour T cell response requires antigen presentation via efficient immunological synapse between antigen presenting cells, e.g. dendritic cells (DC), and specific T cells in an adapted Th1 cytokine context. Nine renal cell carcinoma (RCC) primary culture cells were used as sources of tumour antigens which were loaded on DC (DC-Tu) for autologous T cell activation assays. Cytotoxic activity of lymphocytes stimulated with DC-Tu was evaluated against autologous tumour cells. Assays were performed with 75 grays irradiated tumour cells (Tu irr) and with hydrogen peroxide +/- heat shock (Tu H(2)O(2) +/- HS) treated cells. DC-Tu irr failed to enhance cytotoxic activity of autologous lymphocytes in seven of 13 assays. In all these defective assays, irradiated tumour cells displayed high interleukin (IL)-6 and vascular endothelial growth factor (VEGF) release. Conversely, when tumour cells released low IL-6 levels (n = 4), DC-Tu irr efficiently enhanced CTL activity. When assays were performed with the same RCC cells treated with H(2)O(2) + HS, DC-Tu stimulation resulted in improved CTL activity. H(2)O(2) + HS treatment induced post-apoptotic cell necrosis of tumour cells, totally abrogated their cytokine release [IL-6, VEGF, transforming growth factor (TGF)-beta1] and induced HSP70 expression. Taken together, data show that reduction in IL-6 and VEGF release in the environment of the tumour concomitantly to tumour cell HSP expression favours induction of a stronger anti-tumour CTL response.

Differential effect of ethanol and hydrogen peroxide on barrier function and prostaglandin E2 release in differentiated Caco-2 cells: selective prevention by growth factors.

PubMed

Catalioto, Rose-Marie; Festa, Carla; Triolo, Antonio; Altamura, Maria; Maggi, Carlo Alberto; Giuliani, Sandro

2009-02-01

The present study investigates the effects of ethanol and hydrogen peroxide (H(2)O(2)) on the barrier function and prostaglandin E(2) (PGE(2)) release in differentiated Caco-2 cells. Epithelial barrier integrity was estimated by measuring transepithelial electrical resistance (TEER), the transport of reference compounds and lactate dehydrogenase leakage, the PGE(2) release by enzyme immunoassay. Ethanol and H(2)O(2) decreased TEER and increased the transport of lucifer yellow without affecting that of propranolol and phenylalanine. Only the effects of ethanol were accompanied by PGE(2) production and were reversible without causing long-term cytotoxicity. The cyclooxygenase-2 inhibitor, NS-398, prevented the effect of ethanol on both PGE(2) release and TEER, while inhibition of both cyclooxygenase-2 and tyrosine kinase drastically compromised cell viability and TEER recovery. Hepatocyte growth factor, keratinocyte growth factor or insulin prevented the effect of ethanol on cell permeability, but not on PGE(2) release. Their combination prevented the effect of H(2)O(2). In conclusion, ethanol and H(2)O(2) increased paracellular permeability in differentiated Caco-2 cells without affecting transcellular and active transport. Cyclooxygenase-2 stimulated PGE(2) release mediated the reversible effect of ethanol on tight junctions and, meanwhile, contributed to cell survival. Growth factors, normally present in the intestine, exerted a selective protective effect toward paracellular permeability increase induced by irritants.

Release of growth factors and the effect of age, sex, and severity of injury after long bone fracture. A preliminary report.

PubMed

Pountos, Ippokratis; Georgouli, Theodora; Henshaw, Karen; Bird, Howard; Giannoudis, Peter V

2013-02-01

The systemic response after fracture is regulated by a complex mechanism involving numerous growth factors. In this study, we analyzed the kinetics of key growth factors following lower-limb long bone fracture. Human serum was isolated from 15 patients suffering from lower-limb long bone fracture (tibia/femur) requiring surgical fixation. The levels of platelet-derived growth factor (PDGF-BB), vascular edothelial growth factor (VEGF), insulin growth factor-I (IGF-I), and transforming growth factor β1 (TGF-β1) were assayed by colorimetric ELISA at different time points during the first week after fracture. 10 healthy volunteers made up the control group of the study. Serum levels of the growth factors measured were compared to age, sex, and injury severity score. We found that there was a decline in the levels of PDGF-BB, IGF-I and TGF-β1 during the first 3 days after fracture. However, VEGF levels remained unchanged. The levels of all the growth factors studied then increased, with the highest concentrations noted at day 7 after surgery. No correlation was found between circulating levels of growth factors and age, injury severity score (ISS), blood loss, or fluid administration. There are systemic mitogenic and osteogenic signals after fracture. Important growth factors are released into the peripheral circulation, but early after surgery it appears that serum levels of key growth factors fall. By 7 days postoperatively, the levels had increased considerably. Our findings should be considered in cases where autologous serum is used for ex vivo expansion of mesenchymal stem cells. There should be further evaluation of the use of these molecules as biomarkers of bone union.

Effects of peritoneal fluid from endometriosis patients on the release of vascular endothelial growth factor by neutrophils and monocytes.

PubMed

Na, Yong-Jin; Yang, Seung-Hong; Baek, Dae-Won; Lee, Dong-Hyung; Kim, Ki-Hyung; Choi, Young-Min; Oh, Sung-Tack; Hong, Young-Seoub; Kwak, Jong-Young; Lee, Kyu-Sup

2006-07-01

An increase in the level of the vascular endothelial growth factor (VEGF) production has been reported in the peritoneal fluid (PF) of endometriosis patients. This suggests that changes in the vascular permeability and angiogenesis play an important role in the pathophysiology of this disease. This study examined the effects of the PF obtained from endometriosis patients on the release of VEGF by neutrophils and monocytes. Neutrophils and monocytes were obtained from young healthy volunteers and cultured with the PF obtained from either endometriosis patients (EPF) (n=18) or a control group (CPF) (n=4). A human monocyte/macrophage cell line, THP-1, was cultured with either 10% EPF or 10% CPF. The PF and culture supernatants were assayed for VEGF using ELISA. Real-time PCR and Western blotting were used to measure the VEGF mRNA and protein expression level, respectively. The VEGF levels were higher in the EPF than in the CPF (591+/-75 versus 185+/-31 pg/ml, P<0.05). However, the level of VEGF released by THP-1 cells in CPF and EPF was similar. The EPF induced the release of VEGF by neutrophils, but no VEGF was released by monocytes. The VEGF mRNA expression levels in the neutrophils were higher in the EPF, which was abrogated by cycloheximide, suggesting that the EPF induces the production of VEGF in neutrophils. Neutralizing antibodies against IL-8 and TNF-alpha did not completely prevent the EPF-induced release of VEGF by the neutrophils, even though these growth factors stimulated the release of VEGF by neutrophils. There was a positive correlation between the VEGF and IL-10 concentrations in the EPF (correlation coefficient=0.549, P=0.012, n=18), but the neutralizing antibody of IL-10 did not affect the release of VEGF by the EPF-treated neutrophils. The EPF induced the production and release of VEGF by neutrophils, suggesting that neutrophils may be a source of peritoneal VEGF. In addition, neutrophil-derived VEGF might be a marker for diagnosing endometriosis.

Platelet-Released Growth Factors Modulate the Secretion of Cytokines in Synoviocytes under Inflammatory Joint Disease

PubMed Central

Rasuo, Biljana; Hock, Jennifer Vanessa Phi; Kweider, Nisreen; Fragoulis, Athanassios; Sönmez, Tolga Taha; Jahr, Holger; Pufe, Thomas; Lippross, Sebastian

2017-01-01

The etiology and pathogenesis of rheumatoid arthritis (RA) are marked by a complex interplay of various cell populations and is mediated by different signaling pathways. Traditionally, therapies have primarily focused on pain relief, reducing inflammation and the recovery of joint function. More recently, however, researchers have discussed the therapeutic efficacy of autologous platelet-rich plasma (PRP). The main objective of this work is to examine the influences of platelet-released growth factor (PRGF) on human synoviocytes under inflammatory conditions. Additionally, it is checked to which extend treatment with platelet concentrate influences the release of cytokines form synoviocytes. For this purpose, an in vitro RA model was created by stimulating the cells with the TNF-α. The release of cytokines was measured by ELISA. The cytokine gene expression was analyzed by real-time PCR. It has been observed that the stimulation concentration of 10 ng/ml TNF-α resulted in a significantly increased endogenous secretion and gene expression of IL-6 and TNF-α. The anti-inflammatory effect of PRGF could be confirmed through significant reduction of TNF-α and IL-1β. An induced inflammatory condition seems to cause PRGF to inhibit the release of proinflammatory cytokines. Further study is required to understand the exact effect mechanism of PRGF on synoviocytes. PMID:29348703

Nerve growth factor alters microtubule targeting agent-induced neurotransmitter release but not MTA-induced neurite retraction in sensory neurons.

PubMed

Pittman, Sherry K; Gracias, Neilia G; Fehrenbacher, Jill C

2016-05-01

Peripheral neuropathy is a dose-limiting side effect of anticancer treatment with the microtubule-targeted agents (MTAs), paclitaxel and epothilone B (EpoB); however, the mechanisms by which the MTAs alter neuronal function and morphology are unknown. We previously demonstrated that paclitaxel alters neuronal sensitivity, in vitro, in the presence of nerve growth factor (NGF). Evidence in the literature suggests that NGF may modulate the neurotoxic effects of paclitaxel. Here, we examine whether NGF modulates changes in neuronal sensitivity and morphology induced by paclitaxel and EpoB. Neuronal sensitivity was assessed using the stimulated release of calcitonin gene-related peptide (CGRP), whereas morphology of established neurites was evaluated using a high content screening system. Dorsal root ganglion cultures, maintained in the absence or presence of NGF, were treated from day 7 to day 12 in culture with paclitaxel (300nM) or EpoB (30nM). Following treatment, the release of CGRP was stimulated using capsaicin or high extracellular potassium. In the presence of NGF, EpoB mimicked the effects of paclitaxel: capsaicin-stimulated release was attenuated, potassium-stimulated release was slightly enhanced and the total peptide content was unchanged. In the absence of NGF, both paclitaxel and EpoB decreased capsaicin- and potassium-stimulated release and the total peptide content, suggesting that NGF may reverse MTA-induced hyposensitivity. Paclitaxel and EpoB both decreased neurite length and branching, and this attenuation was unaffected by NGF in the growth media. These differential effects of NGF on neuronal sensitivity and morphology suggest that neurite retraction is not a causative factor to alter neuronal sensitivity. Copyright © 2016 Elsevier Inc. All rights reserved.

Priming Dental Pulp Stem Cells With Fibroblast Growth Factor-2 Increases Angiogenesis of Implanted Tissue-Engineered Constructs Through Hepatocyte Growth Factor and Vascular Endothelial Growth Factor Secretion

PubMed Central

Gorin, Caroline; Rochefort, Gael Y.; Bascetin, Rumeyza; Ying, Hanru; Lesieur, Julie; Sadoine, Jérémy; Beckouche, Nathan; Berndt, Sarah; Novais, Anita; Lesage, Matthieu; Hosten, Benoit; Vercellino, Laetitia; Merlet, Pascal; Le-Denmat, Dominique; Marchiol, Carmen; Letourneur, Didier; Nicoletti, Antonino; Vital, Sibylle Opsahl; Poliard, Anne; Salmon, Benjamin; Germain, Stéphane

2016-01-01

Tissue engineering strategies based on implanting cellularized biomaterials are promising therapeutic approaches for the reconstruction of large tissue defects. A major hurdle for the reliable establishment of such therapeutic approaches is the lack of rapid blood perfusion of the tissue construct to provide oxygen and nutrients. Numerous sources of mesenchymal stem cells (MSCs) displaying angiogenic potential have been characterized in the past years, including the adult dental pulp. Establishment of efficient strategies for improving angiogenesis in tissue constructs is nevertheless still an important challenge. Hypoxia was proposed as a priming treatment owing to its capacity to enhance the angiogenic potential of stem cells through vascular endothelial growth factor (VEGF) release. The present study aimed to characterize additional key factors regulating the angiogenic capacity of such MSCs, namely, dental pulp stem cells derived from deciduous teeth (SHED). We identified fibroblast growth factor-2 (FGF-2) as a potent inducer of the release of VEGF and hepatocyte growth factor (HGF) by SHED. We found that FGF-2 limited hypoxia-induced downregulation of HGF release. Using three-dimensional culture models of angiogenesis, we demonstrated that VEGF and HGF were both responsible for the high angiogenic potential of SHED through direct targeting of endothelial cells. In addition, FGF-2 treatment increased the fraction of Stro-1+/CD146+ progenitor cells. We then applied in vitro FGF-2 priming to SHED before encapsulation in hydrogels and in vivo subcutaneous implantation. Our results showed that FGF-2 priming is more efficient than hypoxia at increasing SHED-induced vascularization compared with nonprimed controls. Altogether, these data demonstrate that FGF-2 priming enhances the angiogenic potential of SHED through the secretion of both HGF and VEGF. Significance The results from the present study show that fibroblast growth factor-2 (FGF-2) priming is more

The Antimicrobial Peptide Human Beta-Defensin-3 Is Induced by Platelet-Released Growth Factors in Primary Keratinocytes

PubMed Central

Lammel, Justus; Tohidnezhad, Mersedeh; Lippross, Sebastian; Behrendt, Peter; Klüter, Tim; Pufe, Thomas; Cremer, Jochen; Jahr, Holger; Rademacher, Franziska; Gläser, Regine; Harder, Jürgen

2017-01-01

Platelet-released growth factors (PRGF) and its related clinically used formulations (e.g., Vivostat Platelet-Rich Fibrin (PRF®)) contain a variety of chemokines, cytokines, and growth factors and are therefore used to support healing of chronic, hard-to-heal, or infected wounds. Human beta-defensin-3 (hBD-3) is an antimicrobial peptide inducibly expressed in human keratinocytes especially upon wounding. The potent antimicrobial activity of hBD-3 together with its wound closure-promoting activities suggests that hBD-3 may play a crucial role in wound healing. Therefore, we analyzed the influence of PRGF on hBD-3 expression in human primary keratinocytes in vitro. In addition, we investigated the influence of Vivostat PRF on hBD-3 expression in artificially generated human skin wounds in vivo. PRGF treatment of primary keratinocytes induced a significant, concentration- and time-dependent increase in hBD-3 gene expression which was partially mediated by the epidermal growth factor receptor (EGFR). In line with these cell culture data, in vivo experiments revealed an enhanced hBD-3 expression in experimentally produced human wounds after the treatment with Vivostat PRF. Thus, the induction of hBD-3 may contribute to the beneficial effects of thrombocyte concentrate lysates in the treatment of chronic or infected wounds. PMID:28811680

Release characteristics and bioactivity of gelatin-tricalcium phosphate membranes covalently immobilized with nerve growth factors.

PubMed

Chen, Pei-Ru; Chen, Ming-Hong; Lin, Feng-Huei; Su, Wen-Yu

2005-11-01

The gelatin-tricalcium phosphate membranes were cross-linking with low concentration glutaraldehyde solution (GTG). This material has good mechanical property, biocompatibility, and is feasible for surgical manipulation. For axonal regeneration, nerve growth factors (NGF) were immobilized onto the composite (GTG) with carbodiimide. The purpose of this study was to evaluate the release characteristics and bioactivity of NGF after covalent immobilization onto the GTG membranes (GEN). NGF immobilized onto and released from the composite was quantified using ELISA method. PC 12 cells were cultured on the GTG and GEN composites. Cell survival, cytotoxicity, and cellular activity were evaluated by total protein content, LDH activity, and MTT assay respectively. Neurite outgrowth assay was used to evaluate the biological activity of NGF released from GEN composite. From ELISA measurement, the releasing curve for NGF showing two distinctive parts with different slopes indicated that NGF were released from the composite in diffusion-controlled mechanism and degradation-controlled mechanism respectively. While culturing with PC 12 cells, LDH leakage results implied that whether GTG composite cross-linked with NGF or not showed little cytotoxicity. The total protein content and cellular activity of PC 12 cells were lower on GTG and GEN membranes than control group. However, 56%+/-3.98 of PC 12 cells showed significant neurite outgrowth on GEN membranes which was statistically higher than GTG without NGF immobilization. In addition, sustained release of bioactive NGF for two months had been demonstrated by neurite outgrowth assay. From these experiments, it can be concluded that the technique used in the present study is capable of immobilizing NGF onto GTG membranes covalently and remaining the bioactivity of NGF. Therefore, GEN composite can be materials for sustained release of bioactive NGF and a candidate for future therapeutic application in nerve repair.

Transforming growth factor-β released by apoptotic white blood cells during red blood cell storage promotes transfusion-induced alloimmunomodulation.

PubMed

Vallion, Romain; Bonnefoy, Francis; Daoui, Anna; Vieille, Loredane; Tiberghien, Pierre; Saas, Philippe; Perruche, Sylvain

2015-07-01

Red blood cell (RBC) alloimmunization is a major immunologic risk of transfusion. However, RBC storage facilitates white blood cell (WBC) apoptosis and apoptotic cells have immunomodulatory properties. We investigated the behavior of WBCs, and apoptosis in particular, in RBC units during storage and then studied the impact of WBC apoptosis on the modulation of posttransfusion alloimmunization in RBC products stored short term. We used a mouse model of alloimmunization to transfused HEL-ovalbumin-Duffy (HOD) surface antigen expressed specifically on RBCs. The presence of circulating anti-HOD immunoglobulin G detected by flow cytometry confirmed immunization to HOD+ RBCs. WBC apoptosis and factors released by apoptotic WBCs during storage were determined and in particular the role of transforming growth factor (TGF)-β was assessed on RBC alloimmunization. In blood stored 72 hours, 30% of WBCs were apoptotic, and transfusion of short-term-stored blood resulted in lesser immunization than did fresh blood or stored leukoreduced (LR) RBCs. WBCs undergoing apoptosis released during short-term storage factors modulating RBC alloimmunization. Indeed apoptotic cell-released factors modulate alloimmunization whereas exogenous apoptotic cells directly transfused with LR RBCs did not. While microparticles released during RBC storage had no immunomodulatory role, TGF-β found in the supernatant of stored blood demonstrated the capacity to favor Treg polarization of naïve CD4+CD25- T cells in vitro and limited RBC alloimmunization in vivo. Indeed, addition of recombinant TGF-β to stored LR RBC transfusion strongly limited posttransfusion RBC alloimmunization. Our findings show that short-term storage of non-LR blood facilitates WBC apoptosis therefore releasing TGF-β that modulates posttransfusion RBC alloimmunization. © 2015 AABB.

Growth factor involvement in tension-induced skeletal muscle growth

NASA Technical Reports Server (NTRS)

Vandenburgh, Herman H.

1993-01-01

Long-term manned space travel will require a better understanding of skeletal muscle atrophy which results from microgravity. Astronaut strength and dexterity must be maintained for normal mission operations and for emergency situations. Although exercise in space slows the rate of muscle loss, it does not prevent it. A biochemical understanding of how gravity/tension/exercise help to maintain muscle size by altering protein synthesis and/or degradation rate should ultimately allow pharmacological intervention to prevent muscle atrophy in microgravity. The overall objective is to examine some of the basic biochemical processes involved in tension-induced muscle growth. With an experimental in vitro system, the role of exogenous and endogenous muscle growth factors in mechanically stimulated muscle growth are examined. Differentiated avian skeletal myofibers can be 'exercised' in tissue culture using a newly developed dynamic mechanical cell stimulator device which simulates different muscle activity patterns. Patterns of mechanical activity which significantly affect muscle growth and metabolic characteristics were found. Both exogenous and endogenous growth factors are essential for tension-induced muscle growth. Exogenous growth factors found in serum, such as insulin, insulin-like growth factors, and steroids, are important regulators of muscle protein turnover rates and mechanically-induced muscle growth. Endogenous growth factors are synthesized and released into the culture medium when muscle cells are mechanically stimulated. At least one family of mechanically induced endogenous factors, the prostaglandins, help to regulate the rates of protein turnover in muscle cells. Endogenously synthesized IGF-1 is another. The interaction of muscle mechanical activity and these growth factors in the regulation of muscle protein turnover rates with our in vitro model system is studied.

Role of platelet-released growth factors in detoxification of reactive oxygen species in osteoblasts.

PubMed

Tohidnezhad, Mersedeh; Wruck, Christoph-Jan; Slowik, Alexander; Kweider, Nisreen; Beckmann, Rainer; Bayer, Andreas; Houben, Astrid; Brandenburg, Lars-Ove; Varoga, Deike; Sönmez, Tolga-Taha; Stoffel, Marcus; Jahr, Holger; Lippross, Sebastian; Pufe, Thomas

2014-08-01

Oxidative stress can impair fracture healing. To protect against oxidative damage, a system of detoxifying and antioxidative enzymes works to reduce the cellular stress. The transcription of these enzymes is regulated by antioxidant response element (ARE). The nuclear factor (erythroid-derived 2)-like2 (Nrf2) plays a major role in transcriptional activation of ARE-driven genes. Recently it has been shown that vascular endothelial growth factor (VEGF) prevents oxidative damage via activation of the Nrf2 pathway in vitro. Platelet-released growth factor (PRGF) is a mixture of autologous proteins and growth factors, prepared from a determined volume of platelet-rich plasma (PRP). It has already used to enhance fracture healing in vitro. The aim of the present study was to elucidate if platelets can lead to upregulation of VEGF and if platelets can regulate the activity of Nrf2-ARE system in primary human osteoblast (hOB) and in osteoblast-like cell line (SAOS-2). Platelets and PRGF were obtained from healthy human donors. HOB and SAOS-2 osteosarcoma cell line were used. The ARE activity was analysed using a dual luciferase reporter assay system. We used Western blot to detect the nuclear accumulation of Nrf2 and the amount of cytosolic antioxidant Thioredoxin Reductase-1 (TXNRD-1), Heme Oxygenase-1 (HO-1) and NAD(P)H quinine oxidoreductase-1 (NQO1). Gene expression analysis was performed by real-time RT PCR. ELISA was used for the quantification of growth factors. The activity of ARE was increased in the presence of PRGF up to 50%. Western blotting demonstrated enhanced nuclear accumulation of Nrf2. This was followed by an increase in the protein expression of the aforementioned downstream targets of Nrf2. Real-time RT PCR data showed an upregulation in the gene expression of the VEGF after PRGF treatment. This was confirmed by ELISA, where the treatment with PRGF induced the protein level of VEGF in both cells. These results provide a new insight into PRGF's mode of

Platelet-released growth factors inhibit proliferation of primary keratinocytes in vitro.

PubMed

Bayer, Andreas; Tohidnezhad, Mersedeh; Berndt, Rouven; Lippross, Sebastian; Behrendt, Peter; Klüter, Tim; Pufe, Thomas; Jahr, Holger; Cremer, Jochen; Rademacher, Franziska; Simanski, Maren; Gläser, Regine; Harder, Jürgen

2018-01-01

Autologous thrombocyte concentrate lysates as platelet-released growth factors (PRGF) or Vivostat Platelet Rich Fibrin (PRF ® ) represent important tools in modern wound therapy, especially in the treatment of chronic, hard-to-heal or infected wounds. Nevertheless, underlying cellular and molecular mechanisms of the beneficial clinical effects of a local wound therapy with autologous thrombocyte concentrate lysates are poorly understood. Recently, we have demonstrated that PRGF induces antimicrobial peptides in primary keratinocytes and accelerates keratinocytes' differentiation. In the present study we analyzed the influence of PRGF on primary human keratinocytes' proliferation. Using the molecular proliferation marker Ki-67 we observed a concentration- and time dependent inhibition of Ki-67 gene expression in PRGF treated primary keratinocytes. These effects were independent from the EGFR- and the IL-6-R pathway. Inhibition of primary keratinocytes' proliferation by PRGF treatment was confirmed in colorimetric cell proliferation assays. Together, these data indicate that the clinically observed positive effects of autologous thrombocytes concentrates in the treatment of chronic, hard-to-heal wounds are not based on an increased keratinocytes proliferation. Copyright © 2017 Elsevier GmbH. All rights reserved.

The characterization of protein release from sericin film in the presence of an enzyme: towards fibroblast growth factor-2 delivery.

PubMed

Nishida, Ayumu; Naganuma, Tsuyoshi; Kanazawa, Takanori; Takashima, Yuuki; Yamada, Masaki; Okada, Hiroaki

2011-07-29

Aqueous preparations of silk protein (sericin) films were prepared to evaluate their biodegradation properties. In the absence of trypsin, sericin film swelled rapidly, kept its shape, and remained unaltered for 28 days or longer due to form β-sheet structures. In the presence of trypsin, sericin film gradually degraded; since the rate depended on the concentration of trypsin, the films likely underwent enzymatic hydrolysis. Sericin film incorporating the model protein drug fluorescein isothiocyanate-albumin (FA) also gradually degraded in the presence of trypsin and resulted in the sustained release of FA for 2 weeks or longer; in contrast, FA release was quite slow in the absence of trypsin. It is expected that sericin film has potential as a biodegradable and drug-releasing carrier. To evaluate the practical applicability of sericin film for the repair of defective tissues, fibroblast growth factor-2 (FGF-2) was incorporated into sericin films and the films were implanted on skull defects in rats. Whereas FGF-2 release was suppressed in the absence of trypsin in vitro, it appears that FGF-2, immobilized by ionic interactions between sericin and FGF-2, can be sustained-released in vivo from films incorporating 2500 or 250 ng of FGF-2 to support the growth of tissue around wounds. Copyright © 2011 Elsevier B.V. All rights reserved.

Dwarf mistletoe-infected red fir: growth after release

Treesearch

Robert F. Scharpf

1979-01-01

Release cutting, live crown ratio, diameter-at-breast height, and dwarf mistletoe (Arceuthobium abietinum f. sp. magnificae). acted to affect radial and height growth of red firs (Abies magnifica A. Murr.). Infected and noninfected red firs responded well to release as expressed by increased radial growth: growth...

Bioresponsive release of insulin-like growth factor-I from its PEGylated conjugate.

PubMed

Braun, Alexandra C; Gutmann, Marcus; Mueller, Thomas D; Lühmann, Tessa; Meinel, Lorenz

2018-06-10

PEGylation of protein ligands, the attachment of polyethylene glycol (PEG) polymers to a therapeutic protein, increases therapeutics' half-life but frequently comes at the cost of reduced bioactivity. We are now presenting a bioinspired strategy leading out of this dilemma. To this end, we selected a position within insulin-like growth factor I (IGF-I) for decoration with a PEG 30kDa -modified protease-sensitive peptide linker (PSL) using a combination of enzymatic and chemical bioorthogonal coupling strategies. The PSL sequence responded to matrix metalloproteinases (MMP) to provide a targeted release in diseased tissue. The IGF-PSL-PEG conjugate had different binding protein affinity, cell proliferation, and endocytosis patterns as compared to the wild type. Exposure of the conjugate to elevated levels of activated MMPs, as present in inflamed tissues, fully reestablished the wild type properties through effective PSL cleavage. In conclusion, this bioinspired approach provided a blueprint for PEGylated therapeutics combining the pharmacokinetic advantages of PEGylation, while locally restoring the full suite of biological potential of therapeutics. Copyright © 2018 Elsevier B.V. All rights reserved.

Chitosan conduits combined with nerve growth factor microspheres repair facial nerve defects

PubMed Central

Liu, Huawei; Wen, Weisheng; Hu, Min; Bi, Wenting; Chen, Lijie; Liu, Sanxia; Chen, Peng; Tan, Xinying

2013-01-01

Microspheres containing nerve growth factor for sustained release were prepared by a compound method, and implanted into chitosan conduits to repair 10-mm defects on the right buccal branches of the facial nerve in rabbits. In addition, chitosan conduits combined with nerve growth factor or normal saline, as well as autologous nerve, were used as controls. At 90 days post-surgery, the muscular atrophy on the right upper lip was more evident in the nerve growth factor and normal sa-line groups than in the nerve growth factor-microspheres and autologous nerve groups. physiological analysis revealed that the nerve conduction velocity and amplitude were significantly higher in the nerve growth factor-microspheres and autologous nerve groups than in the nerve growth factor and normal saline groups. Moreover, histological observation illustrated that the di-ameter, number, alignment and myelin sheath thickness of myelinated nerves derived from rabbits were higher in the nerve growth factor-microspheres and autologous nerve groups than in the nerve growth factor and normal saline groups. These findings indicate that chitosan nerve conduits bined with microspheres for sustained release of nerve growth factor can significantly improve facial nerve defect repair in rabbits. PMID:25206635

Constitutive production and thrombin-induced release of vascular endothelial growth factor by human megakaryocytes and platelets

PubMed Central

Möhle, Robert; Green, David; Moore, Malcolm A. S.; Nachman, Ralph L.; Rafii, Shahin

1997-01-01

We have shown that coculture of bone marrow microvascular endothelial cells with hematopoietic progenitor cells results in proliferation and differentiation of megakaryocytes. In these long-term cultures, bone marrow microvascular endothelial cell monolayers maintain their cellular integrity in the absence of exogenous endothelial growth factors. Because this interaction may involve paracrine secretion of cytokines, we evaluated megakaryocytic cells for secretion of vascular endothelial growth factor (VEGF). Megakaryocytes (CD41a+) were generated by ex vivo expansion of hematopoietic progenitor cells with kit-ligand and thrombopoietin for 10 days and further purified with immunomagnetic microbeads. Using reverse transcription–PCR, we showed that megakaryocytic cell lines (Dami, HEL) and purified megakaryocytes expressed mRNA of the three VEGF isoforms (121, 165, and 189 amino acids). Large quantities of VEGF (>1 ng/106 cells/3 days) were detected in the supernatant of Dami cells, ex vivo-generated megakaryocytes, and CD41a+ cells isolated from bone marrow. The constitutive secretion of VEGF by CD41a+ cells was stimulated by growth factors of the megakaryocytic lineage (interleukin 3, thrombopoietin). Western blotting of heparin–Sepharose-enriched supernatant mainly detected the isoform VEGF165. In addition, immunohistochemistry showed intracytoplasmic VEGF in polyploid megakaryocytes. Thrombin stimulation of megakaryocytes and platelets resulted in rapid release of VEGF within 30 min. We conclude that human megakaryocytes produce and secrete VEGF in an inducible manner. Within the bone marrow microenvironment, VEGF secreted by megakaryocytes may contribute to the proliferation of endothelial cells. VEGF delivered to sites of vascular injury by activated platelets may initiate angiogenesis. PMID:9012841

Encapsulation of basic fibroblast growth factor by polyelectrolyte multilayer microcapsules and its controlled release for enhancing cell proliferation.

PubMed

She, Zhen; Wang, Chunxia; Li, Jun; Sukhorukov, Gleb B; Antipina, Maria N

2012-07-09

Basic fibroblast growth factor (FGF2) is an important protein for cellular activity and highly vulnerable to environmental conditions. FGF2 protected by heparin and bovine serum albumin was loaded into the microcapsules by a coprecipitation-based layer-by-layer encapsulation method. Low cytotoxic and biodegradable polyelectrolytes dextran sulfate and poly-L-arginine were used for capsule shell assembly. The shell thickness-dependent encapsulation efficiency was measured by enzyme-linked immunosorbent assay. A maximum encapsulation efficiency of 42% could be achieved by microcapsules with a shell thickness of 14 layers. The effects of microcapsule concentration and shell thickness on cytotoxicity, FGF2 release kinetics, and L929 cell proliferation were evaluated in vitro. The advantage of using microcapsules as the carrier for FGF2 controlled release for enhancing L929 cell proliferation was analyzed.

Novel drug delivery systems for releasing growth factors to the CNS: focus on Alzheimer's and Parkinson's diseases.

PubMed

Herran, E; Igartua, M; Pedraz, J L; Hernandez, R M

2014-01-01

Alzheimer's disease (AD) and Parkinson's disease (PD) represent the most common neurodegenerative disorders and affect more than 35 million people. Due to the limited effectiveness of available treatments in halting the neurodegenerative process, new therapies, such therapies based on growth factors (GFs), have been investigated. Nevertheless, the efficacies of these new treatments depend not only on the application of neurotrophins but also on the approaches used to deliver these proteins such that they can reach the brain. This review summarises the most widely used drug delivery systems (DDSs) for releasing GFs as possible treatments for AD and PD.

Priming Dental Pulp Stem Cells With Fibroblast Growth Factor-2 Increases Angiogenesis of Implanted Tissue-Engineered Constructs Through Hepatocyte Growth Factor and Vascular Endothelial Growth Factor Secretion.

PubMed

Gorin, Caroline; Rochefort, Gael Y; Bascetin, Rumeyza; Ying, Hanru; Lesieur, Julie; Sadoine, Jérémy; Beckouche, Nathan; Berndt, Sarah; Novais, Anita; Lesage, Matthieu; Hosten, Benoit; Vercellino, Laetitia; Merlet, Pascal; Le-Denmat, Dominique; Marchiol, Carmen; Letourneur, Didier; Nicoletti, Antonino; Vital, Sibylle Opsahl; Poliard, Anne; Salmon, Benjamin; Muller, Laurent; Chaussain, Catherine; Germain, Stéphane

2016-03-01

Tissue engineering strategies based on implanting cellularized biomaterials are promising therapeutic approaches for the reconstruction of large tissue defects. A major hurdle for the reliable establishment of such therapeutic approaches is the lack of rapid blood perfusion of the tissue construct to provide oxygen and nutrients. Numerous sources of mesenchymal stem cells (MSCs) displaying angiogenic potential have been characterized in the past years, including the adult dental pulp. Establishment of efficient strategies for improving angiogenesis in tissue constructs is nevertheless still an important challenge. Hypoxia was proposed as a priming treatment owing to its capacity to enhance the angiogenic potential of stem cells through vascular endothelial growth factor (VEGF) release. The present study aimed to characterize additional key factors regulating the angiogenic capacity of such MSCs, namely, dental pulp stem cells derived from deciduous teeth (SHED). We identified fibroblast growth factor-2 (FGF-2) as a potent inducer of the release of VEGF and hepatocyte growth factor (HGF) by SHED. We found that FGF-2 limited hypoxia-induced downregulation of HGF release. Using three-dimensional culture models of angiogenesis, we demonstrated that VEGF and HGF were both responsible for the high angiogenic potential of SHED through direct targeting of endothelial cells. In addition, FGF-2 treatment increased the fraction of Stro-1+/CD146+ progenitor cells. We then applied in vitro FGF-2 priming to SHED before encapsulation in hydrogels and in vivo subcutaneous implantation. Our results showed that FGF-2 priming is more efficient than hypoxia at increasing SHED-induced vascularization compared with nonprimed controls. Altogether, these data demonstrate that FGF-2 priming enhances the angiogenic potential of SHED through the secretion of both HGF and VEGF. ©AlphaMed Press.

Long-term cytokine and growth factor release from equine platelet-rich fibrin clots obtained with two different centrifugation protocols.

PubMed

Jiménez-Aristizabal, Román F; López, Catalina; Álvarez, María E; Giraldo, Carlos; Prades, Marta; Carmona, Jorge U

2017-09-01

To compare the temporal release (over three weeks) of tumor necrosis factor alpha (TNF-α), interleukin 4 (IL-4), IL-1 receptor antagonist (IL-1ra), platelet-derived growth factor BB (PDGF-BB) and transforming growth factor beta-1 (TGF-β 1 ) from two platelet-rich fibrin (PRF) preparations from equine blood obtained at either 240g/8min or 416g/10min. Whole blood from 10 horses was used to obtain PRF clots by two different centrifugation protocols. After 1h of rest, PRF clots were deposited in wells with culture medium, which was changed at 6h, 24h and then every 48h to 21days. Cytokines and GFs were measured by ELISA at 1h (serum supernatants from PRF clots) and all time points of culture medium change. A negative control (plasma) and a positive control (blood lysate) were also included. There were no relevant differences between the two protocols for the temporal release of proteins. However, a significant (p=0.01) effect of time was noted. All cytokines were detected after 6h of PRF clot culture until day 21. GF were detected at 1h until day 21. The concentrations for these proteins diminished gradually over time. A highly significant (p=0.01) correlation was noticed between all the proteins evaluated. Leukocytes enmeshed in PRF clots were able to produce cytokines, TGF-β 1 and PDGF-BB. These findings demonstrate a paramount role of leukocytes in wound healing induced or modified by PRF clots in mammals. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Physiology of Growth Hormone-Releasing Hormone (GHRH) in Breast Cancer

DTIC Science & Technology

2003-06-01

production of growth hormone-releasing factor by carcinoid and pancreatic islet tumors associated with acromegaly . Prog Clin Biol Res 1981; 74:259-271. (16...promotion of apop- cause of acromegaly . More recently, expression has been tosis. These results indicate that disruption of enaog- demonstrated in tumors

Regulated release of serotonin from axonal growth cones isolated from the fetal rat brain.

PubMed

Mercado, R; Floran, B; Hernandez, J

1998-01-01

In the present work we propose an hypothetical model related to a molecular recognizing system for serotonin in isolated growth cone particles. This model is supported by previous results from our laboratory plus new ones which show that growth cones release serotonin tonically and such release can be stimulated by potassium in a calcium-dependent manner. The present results, together with other author's data, suggest a physiological basis for the putative role of serotonin as a trophic factor during nervous system development.

Growth hormone-releasing peptides.

PubMed

Ghigo, E; Arvat, E; Muccioli, G; Camanni, F

1997-05-01

Growth hormone-releasing peptides (GHRPs) are synthetic, non-natural peptides endowed with potent stimulatory effects on somatotrope secretion in animals and humans. They have no structural homology with GHRH and act via specific receptors present either at the pituitary or the hypothalamic level both in animals and in humans. The GHRP receptor has recently been cloned and, interestingly, it does not show sequence homology with other G-protein-coupled receptors known so far. This evidence strongly suggests the existence of a natural GHRP-like ligand which, however, has not yet been found. The mechanisms underlying the GHRP effect are still unclear. At present, several data favor the hypothesis that GHRPs could act by counteracting somatostatinergic activity both at the pituitary and the hypothalamic level and/or, at least partially, via a GHRH-mediated mechanism. However, the possibility that GHRPs act via an unknown hypothalamic factor (U factor) is still open. GHRP-6 was the first hexapeptide to be extensively studied in humans. More recently, a heptapeptide, GHRP-1, and two other hexapeptides, GHRP-2 and Hexarelin, have been synthesized and are now available for human studies. Moreover, non-peptidyl GHRP mimetics have been developed which act via GHRP receptors and their effects have been clearly demonstrated in animals and in humans in vivo. Among non-peptidyl GHRPs, MK-0677 seems the most interesting molecule. The GH-releasing activity of GHRPs is marked and dose-related after intravenous, subcutaneous, intranasal and even oral administration. The effect of GHRPs is reproducible and undergoes partial desensitization, more during continuous infusion, less during intermittent administration: in fact, prolonged administration of GHRPs increases IGF-1 levels both in animals and in humans. The GH-releasing effect of GHRPs does not depend on sex but undergoes age-related variations. It increases from birth to puberty, persists at a similar level in adulthood and

Human Dental Pulp Stem Cells Suppress Alloantigen-induced Immunity by Stimulating T Cells to Release Transforming Growth Factor Beta.

PubMed

Kwack, Kyu Hwan; Lee, Jung Min; Park, Sang Hyuk; Lee, Hyeon Woo

2017-01-01

Human dental pulp stem cells (hDPSCs) are ideal candidates for regenerating damaged dental tissue. To examine the possibility that hDPSCs may be used to regenerate pulp, we tested their in vitro effects on acute allogeneic immune responses. A peripheral blood mononuclear cell (PBMC) proliferation assay and immunoglobulin (Ig) production assay were performed to evaluate the immunosuppressive properties of hDPSCs. The mixed lymphocyte reaction was suppressed by incubation with hDPSCs. Transforming growth factor beta (TGF-β) was the major soluble factor responsible for inhibiting the allogeneic proliferation of PBMCs. The production of IgM and IgG by allogeneic activation of responder B lymphocytes was also completely abrogated by TGF-β released from hDPSCs via interferon gamma in response to activation of the responder T lymphocytes. hDPSCs inhibit acute allogeneic immune responses by their release of TGF-β as a result of allogeneic stimulation of T lymphocytes. This study provides an insight into the potential clinical use of hDPSCs for allogeneic transplantation. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Modeling Vascularized Bone Regeneration Within a Porous Biodegradable CaP Scaffold Loaded with Growth Factors

PubMed Central

Sun, X; Kang, Y; Bao, J; Zhang, Y; Yang, Y; Zhou, X

2013-01-01

Osteogenetic microenvironment is a complex constitution in which extracellular matrix (ECM) molecules, stem cells and growth factors each interact to direct the coordinate regulation of bone tissue development. Importantly, angiogenesis improvement and revascularization are critical for osteogenesis during bone tissue regeneration processes. In this study, we developed a three-dimensional (3D) multi-scale system model to study cell response to growth factors released from a 3D biodegradable porous calcium phosphate (CaP) scaffold. Our model reconstructed the 3D bone regeneration system and examined the effects of pore size and porosity on bone formation and angiogenesis. The results suggested that scaffold porosity played a more dominant role in affecting bone formation and angiogenesis compared with pore size, while the pore size could be controlled to tailor the growth factor release rate and release fraction. Furthermore, a combination of gradient VEGF with BMP2 and Wnt released from the multi-layer scaffold promoted angiogenesis and bone formation more readily than single growth factors. These results demonstrated that the developed model can be potentially applied to predict vascularized bone regeneration with specific scaffold and growth factors. PMID:23566802

Effects of artemisinin sustained-release granules on mixed alga growth and microcystins production and release.

PubMed

Ni, Lixiao; Li, Danye; Hu, Shuzhen; Wang, Peifang; Li, Shiyin; Li, Yiping; Li, Yong; Acharya, Kumud

2015-12-01

To safely and effectively apply artemisinin sustained-release granules to control and prevent algal water-blooms, the effects of artemisinin and its sustained-release granules on freshwater alga (Scenedesmus obliquus (S. obliquus) and Microcystis aeruginosa (M. aeruginosa)), as well as the production and release of microcystins (MCs) were studied. The results showed that artemisinin sustained-release granules inhibited the growth of M. aeruginosa (above 95% IR) and S. obliquus (about 90% IR), with M. aeruginosa more sensitive. The artemisinin sustained-release granules had a longer inhibition effect on growth of pure algae and algal coexistence than direct artemisinin dosing. The artemisinin sustained-release granules could decrease the production and release of algal toxins due to the continued stress of artemisinin released from artemisinin sustained-release granules. There was no increase in the total amount of MC-LR in the algal cell culture medium.

Controlled-release of epidermal growth factor from cationized gelatin hydrogel enhances corneal epithelial wound healing.

PubMed

Hori, Kuniko; Sotozono, Chie; Hamuro, Junji; Yamasaki, Kenta; Kimura, Yu; Ozeki, Makoto; Tabata, Yasuhiko; Kinoshita, Shigeru

2007-04-02

We designed a new ophthalmic drug-delivery system for epidermal growth factor (EGF) from the biodegradable hydrogel of cationized gelatin. We placed a cationized gelatin hydrogel (CGH) with incorporated (125)I-labelled EGF in the conjunctival sac of mice and measured the residual radioactivity at different times to evaluate the in vivo profile of EGF release. Approximately 60-67% and 10-12% of EGF applied initially remained 1 and 7 days after application, respectively; whereas EGF delivered in topically applied solution or via EGF impregnation of soft contact lenses disappeared within the first day. We also placed CGH films with 5.0 mug of incorporated EGF on round corneal defects in rabbits to evaluate the healing process using image analysis software and to assess epithelial proliferation immunohistochemically by counting the number of Ki67-positive cells. The application of a CGH film with incorporated EGF resulted in a reduction in the epithelial defect in rabbit corneas accompanied by significantly enhanced epithelial proliferation compared with the reduction seen after the topical application of EGF solution or the placement of an EGF-free CGH film. The controlled release of EGF from a CGH placed over a corneal epithelial defect accelerated ocular surface wound healing.

Targeted delivery of growth factors in ischemic stroke animal models.

PubMed

Rhim, Taiyoun; Lee, Minhyung

2016-01-01

Ischemic stroke is caused by reduced blood supply and leads to loss of brain function. The reduced oxygen and nutrient supply stimulates various physiological responses, including induction of growth factors. Growth factors prevent neuronal cell death, promote neovascularization, and induce cell growth. However, the concentration of growth factors is not sufficient to recover brain function after the ischemic damage, suggesting that delivery of growth factors into the ischemic brain may be a useful treatment for ischemic stroke. In this review, various approaches for the delivery of growth factors to ischemic brain tissue are discussed, including local and targeting delivery systems. To develop growth factor therapy for ischemic stroke, important considerations should be taken into account. First, growth factors may have possible side effects. Thus, concentration of growth factors should be restricted to the ischemic tissues by local administration or targeted delivery. Second, the duration of growth factor therapy should be optimized. Growth factor proteins may be degraded too fast to have a high enough therapeutic effect. Therefore, delivery systems for controlled release or gene delivery may be useful. Third, the delivery systems to the brain should be optimized according to the delivery route.

Role of Fibroblast Growth Factor Binding Protein-1 in Mammary Development and Tumorigenesis

DTIC Science & Technology

2009-10-01

AD_________________ Award Number: W81XWH-06-1-0763 TITLE: Role of Fibroblast Growth Factor ...2009 4. TITLE AND SUBTITLE Role of Fibroblast Growth Factor Binding Protein-1 in Mammary Development 5a. CONTRACT NUMBER and Tumorigenesis...Release; Distribution Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT 15. SUBJECT TERMS Fibroblast Growth Factor Binding Protein-1

Inhibition of vascular endothelial growth factor-induced angiogenesis suppresses tumour growth in vivo

NASA Astrophysics Data System (ADS)

Kim, K. Jin; Li, Bing; Winer, Jane; Armanini, Mark; Gillett, Nancy; Phillips, Heidi S.; Ferrara, Napoleone

1993-04-01

THE development of new blood vessels (angiogenesis) is required for many physiological processes including embryogenesis, wound healing and corpus luteum formation1,2. Blood vessel neoformation is also important in the pathogenesis of many disorders1-5, particularly rapid growth and metastasis of solid tumours3-5. There are several potential mediators of tumour angiogenesis, including basic and acidic fibroblast growth factors, tumour necrosis factor-α and transforming factors-α and -β 1,2. But it is unclear whether any of these agents actually mediates angiogenesis and tumour growth in vivo. Vascular endothelial growth factor (VEGF) is an endothelial cell-specific mitogen and an angiogenesis inducer released by a variety of tumour cells and expressed in human tumours in situ. To test whether VEGF may be a tumour angiogenesis factor in vivo, we injected human rhabdomyosar-coma, glioblastoma multiforme or leiomyosarcoma cell lines into nude mice. We report here that treatment with a monoclonal antibody specific for VEGF inhibited the growth of the tumours, but had no effect on the growth rate of the tumour cells In vitro. The density of vessels was decreased in the antibody-treated tumours. These findings demonstrate that inhibition of the action of an angiogenic factor spontaneously produced by tumour cells may suppress tumour growth in vivo.

Combination Growth Factor Therapy via Electrostatically Assembled Wound Dressings Improves Diabetic Ulcer Healing In Vivo.

PubMed

Almquist, Benjamin D; Castleberry, Steven A; Sun, Julia B; Lu, Alice Y; Hammond, Paula T

2015-10-01

Chronic skin ulcerations are a common complication of diabetes mellitus, affecting up to one in four diabetic individuals. Despite the prevalence of these wounds, current pharmacologic options for treating them remain limited. Growth factor-based therapies have displayed a mixed ability to drive successful healing, which may be due to nonoptimal delivery strategies. Here, a method for coating commercially available nylon dressings using the layer-by-layer process is described to enable both sustained release and independent control over the release kinetics of vascular endothelial growth factor 165 and platelet-derived growth factor BB. It is shown that the use of strategically spaced diffusion barriers formed spontaneously by disulfide bonds enables independent control over the release rates of incorporated growth factors, and that in vivo these dressings improve several aspects of wound healing in db/db mice. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Collagen and Stretch Modulate Autocrine Secretion of Insulin-like Growth Factor-1 and Insulin-like Growth Factor Binding Proteins from Differentiated Skeletal Muscle Cells

NASA Technical Reports Server (NTRS)

Perrone, Carmen E.; Fenwick-Smith, Daniela; Vandenburgh, Herman H.

1995-01-01

Stretch-induced skeletal muscle growth may involve increased autocrine secretion of insulin-like growth factor-1 (IGF-1) since IGF-1 is a potent growth factor for skeletal muscle hypertrophy, and stretch elevates IGF-1 mRNA levels in vivo. In tissue cultures of differentiated avian pectoralis skeletal muscle cells, nanomolar concentrations of exogenous IGF-1 stimulated growth in mechanically stretched but not static cultures. These cultures released up to 100 pg of endogenously produced IGF-1/micro-g of protein/day, as well as three major IGF binding proteins of 31, 36, and 43 kilodaltons (kDa). IGF-1 was secreted from both myofibers and fibroblasts coexisting in the muscle cultures. Repetitive stretch/relaxation of the differentiated skeletal muscle cells stimulated the acute release of IGF-1 during the first 4 h after initiating mechanical activity, but caused no increase in the long-term secretion over 24-72 h of IGF-1, or its binding proteins. Varying the intensity and frequency of stretch had no effect on the long-term efflux of IGF-1. In contrast to stretch, embedding the differentiated muscle cells in a three-dimensional collagen (Type I) matrix resulted in a 2-5-fold increase in long-term IGF-1 efflux over 24-72 h. Collagen also caused a 2-5-fold increase in the release of the IGF binding proteins. Thus, both the extracellular matrix protein type I collagen and stretch stimulate the autocrine secretion of IGF-1, but with different time kinetics. This endogenously produced growth factor may be important for the growth response of skeletal myofibers to both types of external stimuli.

In Vivo Evidence for Epidermal Growth Factor Receptor (EGFR)-mediated Release of Prolactin from the Pituitary Gland

PubMed Central

Dahlhoff, Maik; Blutke, Andreas; Wanke, Rüdiger; Wolf, Eckhard; Schneider, Marlon R.

2011-01-01

Members of the epidermal growth factor receptor (EGFR/ERBB) system are essential local regulators of mammary gland development and function. Emerging evidence suggests that EGFR signaling may also influence mammary gland activity indirectly by promoting the release of prolactin from the pituitary gland in a MAPK and estrogen receptor-α (ERα)-dependent manner. Here, we report that overexpression of the EGFR ligand betacellulin (BTC) causes a lactating-like phenotype in the mammary gland of virgin female mice including the major hallmarks of lactogenesis. BTC transgenic (BTC-tg) females showed reduced levels of prolactin in the pituitary gland and increased levels of the hormone in the circulation. Furthermore, treatment of BTC-tg females with bromocriptine, an inhibitor of prolactin secretion, blocked the development of the lactation-like phenotype, suggesting that it is caused by central release of prolactin rather than by local actions of BTC in the mammary gland. Introduction of the antimorphic Egfr allele Wa5 also blocked the appearance of the mammary gland alterations, revealing that the phenotype is EGFR-dependent. We detected an increase in MAPK activity, but unchanged phosphorylation of ERα in the pituitary gland of BTC-tg females as compared with control mice. These results provide the first functional evidence in vivo for a role of the EGFR system in regulating mammary gland activity by modulating prolactin release from the pituitary gland. PMID:21914800

Structural study of human growth hormone-releasing factor fragment (1?29) by vibrational spectroscopy

NASA Astrophysics Data System (ADS)

Carmona, P.; Molina, M.; Lasagabaster, A.

1995-05-01

The conformational structure of fragment 1-29 of human growth hormone releasing factor, hGHRF (1-29), in aqueous solution and in the solid state is investigated by infrared and Raman spectroscopy. The polypeptide backbone is found to be unordered in the solid state. However, the spectra of the peptide prepared as 5% (w/w) aqueous solutions show that approximately 28% of the peptide is involved in intermolecular β-sheet aggregation. The remainder of the peptide exists largely as disordered and β-sheet conformations with a small portion of α-helices. Tyrosine residues are found to be exposed to the solvent. The secondary structures are quantitatively examined through infrared spectroscopy, the conformational percentages being near those obtained by HONDAet al. [ Biopolymers31, 869 (1991)] using circular dichroism. The fast hydrogen/deuterium exchange in peptide groups and the absence of any NMR sign indicative of ordered structure [ G. M. CLOREet al., J. Molec. Biol.191, 553 (1986)] support that the solution conformations of the non-aggregated peptide interconvert in dynamic equilibrium. Some physiological advantages that may derive from this conformational flexibility are also discussed

Epidermal growth factor-like growth factors prevent apoptosis of alcohol-exposed human placental cytotrophoblast cells.

PubMed

Wolff, Garen S; Chiang, Po Jen; Smith, Susan M; Romero, Roberto; Armant, D Randall

2007-07-01

Maternal alcohol abuse during pregnancy can produce an array of birth defects comprising fetal alcohol syndrome. A hallmark of fetal alcohol syndrome is intrauterine growth retardation, which is associated with elevated apoptosis of placental cytotrophoblast cells. Using a human first trimester cytotrophoblast cell line, we examined the relationship between exposure to ethanol and cytotrophoblast survival, as well as the ameliorating effects of epidermal growth factor (EGF)-like growth factors produced by human cytotrophoblast cells. After exposure to 0-100 mM ethanol, cell death was quantified by the TUNEL method, and expression of the nuclear proliferation marker, Ki67, was measured by immunohistochemistry. The mode of cell death was determined by assessing annexin V binding, caspase 3 activation, pyknotic nuclear morphology, reduction of TUNEL by caspase inhibition, and cellular release of lactate dehydrogenase. Ethanol significantly reduced proliferation and increased cell death approximately 2.5-fold through the apoptotic pathway within 1-2 h of exposure to 50 mM alcohol. Exposure to 25-50 mM ethanol significantly increased transforming growth factor alpha (TGFA) and heparin-binding EGF-like growth factor (HBEGF), but not EGF or amphiregulin (AREG). When cytotrophoblasts were exposed concurrently to 100 mM ethanol and 1 nM HBEGF or TGFA, the increase in apoptosis was prevented, while EGF ameliorated at 10 nM and AREG was weakly effective. HBEGF survival-promoting activity required ligation of either of its cognate receptors, HER1 or HER4. These findings reveal the potential for ethanol to rapidly induce cytotrophoblast apoptosis. However, survival factor induction could provide cytotrophoblasts with an endogenous cytoprotective mechanism.

Multifunctional mesoporous bioactive glasses for effective delivery of therapeutic ions and drug/growth factors.

PubMed

Wu, Chengtie; Chang, Jiang

2014-11-10

Regeneration of large-size bone defects represents a significant challenge clinically, which requires the use of scaffolds with multifunction, such as anti-bacterial activity, and stimulation of osteogenesis and angiogenesis. It is known that functional ions or drug/growth factors play an important role to stimulate tissue regeneration. Mesoporous bioactive glasses (MBG) possess excellent bioactivity and drug-delivery ability as well as effective ionic release in the body fluids microenvironment due to its specific mesoporous structure and large surface area. For these reasons, functional ions (e.g. lithium (Li), strontium (Sr), Copper (Cu) and Boron (B)) and drug/growth factors (e.g. dexamethasone, vascular endothelial growth factor (VEGF) and bone morphogenetic protein (BMP)) have been incorporated into MBG, which shows high loading efficiency and effective release. The release of therapeutic ions and drug/growth factors from MBG offers it multifunctional properties, such as improved osteogenesis, angiogenesis, anti-bacterial/cancer activity. However, there is no a systematic review about delivery of therapeutic ions and drugs/growth factors from MBG for the functional effect on the tissue regeneration despite that significant progress has been achieved in the past five years. Therefore, in this review, we mainly focused on the new advances for the functional effect of delivering therapeutic ions and drugs/growth factors on the ostegeogenesis, angiogenesis and antibacterial activity. It is expected that the review will offer new concept to develop multifunctional biomaterials for bone regeneration by the synergistic effect of therapeutic ions and drug/growth factors. Copyright © 2014 Elsevier B.V. All rights reserved.

Do growth hormone-releasing peptides act as ghrelin secretagogues?

PubMed

Ahnfelt-Rønne, I; Nowak, J; Olsen, U B

2001-02-01

NN703 is an orally active and selective growth hormone secretagogue (GHS) that was derived from growth hormone-releasing peptide-1(GHRP-1) via ipamorelin by a peptidomimetic approach and has now entered into phase II clinical trials. When the disposition in rats of NN703 and GHRP-6 was studied using whole-body autoradiography following administration of an iv dose of radiolabeled material, we found that a substantial amount of these secretagogues accumulate in the glandular part of the stomach. Because this is the site of synthesis and secretion of ghrelin, the endogenous GHS, we investigated the effect of resection of the gastrointestinal (GI) tract on growth hormone (GH) release induced by GHRP-6. This procedure significantly attenuated the GH secretion response by 60-70%. By contrast, the effect of GH-releasing hormone on GH release was not inhibited. The binding of GHRPs to the glandular part of the stomach and the blunted GH response to GHRP-6 following resection of the GI tract suggest a role for ghrelin as a mediator of part of the GH-releasing effect of GHRPs.

Sustained Release of Transforming Growth Factor-β1 from Platelet-Rich Chondroitin Sulfate Glycosaminoglycan Gels

PubMed Central

Birdwhistell, Kate E.; Karumbaiah, Lohitash; Franklin, Samuel P.

2018-01-01

Activated platelet-rich plasma (PRP), also referred to as platelet-rich fibrin (PRF), has been used to augment numerous techniques of cartilage repair in the knee but does not always result in superior quality of repair tissue. One possible reason that PRF does not consistently result in excellent cartilage regeneration is the transiency of growth factor provision with PRF. The objective of this study was to compare the release of transforming growth factor (TGF)-β1 from PRF and from PRP combined with a novel chondroitin sulfate glycosaminoglycan (CS-GAG) gel. PRP was prepared from nine healthy dogs and split into two aliquots: one activated with bovine thrombin and calcium chloride (CaCl2) to form PRF and the other aliquot was used to rehydrate a lyophilized CS-GAG gel. Both PRF and the CS-GAG gels were incubated in media for 13 days and media were collected, stored, and replaced every 48 hours and the concentration of TGF-β1 quantified in the media using an enzyme-linked immunosorbent assay. Concentrations of TGF-β1 in the media were up to three times greater with the CS-GAG gels and were significantly (p < 0.05) greater than with PRF on days 3, 5, 7, 9, and 13. Furthermore, TGF-β1 elution was still substantial at day 13 with the use of the CS-GAG gels. Additional in vitro work is warranted to characterize TGF-β1 elution from this CS-GAG gel with human PRP and to determine whether the use of these CS-GAG gels can augment cartilage repair in vivo. PMID:28645130

Oral administration of arginine enhances the growth hormone response to growth hormone releasing hormone in short children.

PubMed

Loche, S; Carta, D; Muntoni, A C; Corda, R; Pintor, C

1993-10-01

We have evaluated the effect of oral administration of arginine chlorhydrate on the growth hormone response to growth hormone releasing hormone in a group of nine short prepubertal children (six boys and four girls). Arginine chlorhydrate 10 g, administered orally 60 min before an i.v. bolus injection of growth hormone releasing hormone 1-29, 1 microgram/kg, significantly enhanced the growth hormone response to the neuropeptide, confirming the results of previous studies which used the i.v. route. Furthermore, our data strengthen the view that the effects of arginine chlorhydrate on growth hormone secretion are mediated by inhibition of endogenous somatostatin release.

Evaluation of an injectable polymeric delivery system for controlled and localized release of biological factors to promote therapeutic angiogenesis

NASA Astrophysics Data System (ADS)

Rocker, Adam John

Cardiovascular disease remains as the leading cause of death worldwide and is frequently associated with partial or full occlusion of coronary arteries. Currently, angioplasty and bypass surgery are the standard approaches for treating patients with these ischemic heart conditions. However, a large number of patients cannot undergo these procedures. Therapeutic angiogenesis provides a minimally invasive tool for treating cardiovascular diseases by inducing new blood vessel growth from the existing vasculature. Angiogenic growth factors can be delivered locally through gene, cell, and protein therapy. Natural and synthetic polymer growth factor delivery systems are under extensive investigation due their widespread applications and promising therapeutic potential. Although biocompatible, natural polymers often suffer from batch-to-batch variability which can cause unpredictable growth factor release rates. Synthetic polymers offer advantages for growth factor delivery as they can be easily modified to control release kinetics. During the angiogenesis process, vascular endothelial growth factor (VEGF) is necessary to initiate neovessel formation while platelet-derived growth factor (PDGF) is needed later to help stabilize and mature new vessels. In the setting of myocardial infarction, additional anti-inflammatory cytokines like IL-10 are needed to help optimize cardiac repair and limit the damaging effects of inflammation following infarction. To meet these angiogenic and anti-inflammatory needs, an injectable polymer delivery system created from a sulfonated reverse thermal gel encapsulating micelle nanoparticles was designed and evaluated. The sulfonate groups on the thermal gel electrostatically bind to VEGF which controls its release rate, while the micelles are loaded with PDGF and are slowly released as the gel degrades. IL-10 was loaded into the system as well and diffused from the gel over time. An in vitro release study was performed which demonstrated the

A novel mechanism of vascular endothelial growth factor, leptin and transforming growth factor-beta2 sequestration in a subpopulation of human ovarian follicle cells.

PubMed

Antczak, M; Van Blerkom, J; Clark, A

1997-10-01

This study describes the occurrence of a highly specialized subpopulation of granulosa and cumulus oophorus cells that accumulate and sequester specific growth factors by a novel mechanism. These cells are characterized by multiple balloon-like processes tethered to the cell by means of a slender stalk of plasma membrane. Time-lapse analyses demonstrate that these tethered structures (TS) form in minutes and frequently detach from the cell with the bulbous portion remaining motile on the cell surface. Serial section reconstruction of transmission electron microscopic images shows a specific and stable intracellular organization in which an apparent secretory compartment composed of densely packed vacuoles, vesicles, and cisternae is separated by a thick filamentous network from a nuclear compartment containing mitochondria, polyribosomes, lipid inclusions, and rough-surfaced endoplasmic reticulum. Immunofluorescent analysis performed during the formation of these structures showed a progressive accumulation of vascular endothelial growth factor, leptin, and transforming growth factor-beta2 in the bulbous region. TS were identified in newly aspirated masses of granulosa and cumulus oophorus, and their production persists for months in culture. Observations of TS-forming cells made over several days of culture indicates that their production is episodic and factor release from these cells may be pulsatile. The findings suggest that a novel method of growth factor storage and release by an apparent apocrine-like mechanism occurs in the human ovarian follicle. The results are discussed with respect to possible roles in pre- and post-ovulatory follicular development.

Role of G protein-coupled estrogen receptor-1, matrix metalloproteinases 2 and 9, and heparin binding epidermal growth factor-like growth factor in estradiol-17β-stimulated bovine satellite cell proliferation.

PubMed

Kamanga-Sollo, E; Thornton, K J; White, M E; Dayton, W R

2014-10-01

In feedlot steers, estradiol-17β (E2) and combined E2 and trenbolone acetate (a testosterone analog) implants enhance rate and efficiency of muscle growth; and, consequently, these compounds are widely used as growth promoters. Although the positive effects of E2 on rate and efficiency of bovine muscle growth are well established, the mechanisms involved in these effects are not well understood. Combined E2 and trenbolone acetate implants result in significantly increased muscle satellite cell number in feedlot steers. Additionally, E2 treatment stimulates proliferation of cultured bovine satellite cells (BSC). Studies in nonmuscle cells have shown that binding of E2 to G protein-coupled estrogen receptor (GPER)-1 results in activation of matrix metalloproteinases 2 and 9 (MMP2/9) resulting in proteolytic release of heparin binding epidermal growth factor-like growth factor (hbEGF) from the cell surface. Released hbEGF binds to and activates the epidermal growth factor receptor resulting in increased proliferation. To assess if GPER-1, MMP2/9, and/or hbEGF are involved in the mechanism of E2-stimulated BSC proliferation, we have examined the effects of G36 (a specific inhibitor of GPER-1), CRM197 (a specific inhibitor of hbEGF), and MMP-2/MMP-9 Inhibitor II (an inhibitor of MMP2/9 activity) on E2-stimulated BSC proliferation. Inhibition of GPER-1, MMP2/9, or hbEGF suppresses E2-stimulated BSC proliferation (P < 0.001) suggesting that all these are required in order for E2 to stimulate BSC proliferation. These results strongly suggest that E2 may stimulate BSC proliferation by binding to GPER-1 resulting in MMP2/9-catalyzed release of cell membrane-bound hbEGF and subsequent activation of epidermal growth factor receptor by binding of released hbEGF. Copyright © 2014 Elsevier Inc. All rights reserved.

Transforming growth factor alpha, Shope fibroma growth factor, and vaccinia growth factor can replace myxoma growth factor in the induction of myxomatosis in rabbits.

PubMed

Opgenorth, A; Nation, N; Graham, K; McFadden, G

1993-02-01

The epidermal growth factor (EGF) homologues encoded by vaccinia virus, myxoma virus, and malignant rabbit fibroma virus have been shown to contribute to the pathogenicity of virus infection upon inoculation of susceptible hosts. However, since the primary structures of these growth factors and the disease profiles induced by different poxvirus genera vary substantially, the degree to which the various EGF homologues perform similar roles in viral pathogenesis remains unclear. In order to determine whether different EGF-like growth factors can perform qualitatively similar functions in the induction of myxomatosis in rabbits, we created recombinant myxoma virus variants in which the native growth factor, myxoma growth factor (MGF), was disrupted and replaced with either vaccinia virus growth factor, Shope fibroma growth factor, or rat transforming growth factor alpha. Unlike the control virus containing an inactivated MGF gene, which caused marked attenuation of the disease syndrome and substantially less proliferation of the epithelial cell layers in the conjunctiva and respiratory tract, the recombinant myxoma virus strains expressing heterologous growth factors produced infections which were both clinically and histopathologically indistinguishable from wild-type myxomatosis. We conclude that these poxviral and cellular EGF-like growth factors, which are diverse with respect to primary structure and origin, have similar biological functions in the context of myxoma virus pathogenesis and are mitogenic for the same target cells.

Localized delivery of growth factors for periodontal tissue regeneration: role, strategies, and perspectives.

PubMed

Chen, Fa-Ming; Shelton, Richard M; Jin, Yan; Chapple, Iain L C

2009-05-01

Difficulties associated with achieving predictable periodontal regeneration, means that novel techniques need to be developed in order to regenerate the extensive soft and hard tissue destruction that results from periodontitis. Localized delivery of growth factors to the periodontium is an emerging and versatile therapeutic approach, with the potential to become a powerful tool in future regenerative periodontal therapy. Optimized delivery regimes and well-defined release kinetics appear to be logical prerequisites for safe and efficacious clinical application of growth factors and to avoid unwanted side effects and toxicity. While adequate concentrations of growth factor(s) need to be appropriately localized, delivery vehicles are also expected to possess properties such as protein protection, precision in controlled release, biocompatibility and biodegradability, self-regulated therapeutic activity, potential for multiple delivery, and good cell/tissue penetration. Here, current knowledge, recent advances, and future possibilities of growth factor delivery strategies are outlined for periodontal regeneration. First, the role of those growth factors that have been implicated in the periodontal healing/regeneration process, general requirements for their delivery, and the different material types available are described. A detailed discussion follows of current strategies for the selection of devices for localized growth factor delivery, with particular emphasis placed upon their advantages and disadvantages and future prospects for ongoing studies in reconstructing the tooth supporting apparatus.

Resveratrol inhibits proteinase-activated receptor-2-induced release of soluble vascular endothelial growth factor receptor-1 from human endothelial cells

PubMed Central

Al-Ani, Bahjat

2013-01-01

We recently reported that (i) activation of the proinflammatory receptor, proteinase-activated receptor-2 (PAR-2) caused the release of an important biomarker in preeclampsia, soluble vascular endothelial growth factor receptor-1 (sVEGFR-1, also known as sFlt-1) from human umbilical vein endothelial cells (HUVECs), and (ii) that the anti-oxidant and anti-inflammatory agent, resveratrol, is capable of inhibiting the proinflammatory cytokine-induced sVEGFR-1 release from human placenta. Based on these findings and because PAR-2 is upregulated by proinflammatory cytokines, we sought to determine whether resveratrol can inhibit PAR-2-induced sVEGFR-1 release. PAR-2 expressing cells, HUVECs and human embryonic kidney cells (HEK-293) transfected with a human VEGFR-1 promoter-luciferase reporter construct were incubated with PAR-2-activating peptide and/or resveratrol. Cell supernatants were assayed for sVEGFR-1 by enzyme-linked immunosorbent assay (ELISA), and VEGFR-1 promoter-luciferase assay was performed on the harvested cell lysates. Preincubation of HEK-293 cells with resveratrol significantly inhibited PAR-2-induced VEGFR-1 promoter activity without affecting cell viability as assessed by MTT assay. The addition of resveratrol also blocked PAR-2-mediated sVEGFR-1 release from HUVECs. The present study demonstrates that resveratrol suppressed both VEGFR-1 promoter activity and sVEGFR-1 protein release induced by PAR-2 activation, which further endorses our recent findings of a potential therapeutic role for resveratrol in preeclampsia. PMID:26933402

Crown Release Promotes Faster Diameter Growth of Pole-Size Black Walnut

Treesearch

Robert E. Phares; Robert D. Williams

1971-01-01

Complete crown release more than doubles the diameter growth of pole-size black walnut trees in southern Indiana over a 10-year period. Partially released trees gew about 50 percent more than unreleased trees. The faster growth of the released trees was directly related to increases in crown-area expansion. Most of the study trees produced bole sprouts; however, the...

Generating favorable growth factor and protease release profiles to enable extracellular matrix accumulation within an in vitro tissue engineering environment.

PubMed

Zhang, Xiaoqing; Battiston, Kyle G; Labow, Rosalind S; Simmons, Craig A; Santerre, J Paul

2017-05-01

Tissue engineering (particularly for the case of load-bearing cardiovascular and connective tissues) requires the ability to promote the production and accumulation of extracellular matrix (ECM) components (e.g., collagen, glycosaminoglycan and elastin). Although different approaches have been attempted in order to enhance ECM accumulation in tissue engineered constructs, studies of underlying signalling mechanisms that influence ECM deposition and degradation during tissue remodelling and regeneration in multi-cellular culture systems have been limited. The current study investigated vascular smooth muscle cell (VSMC)-monocyte co-culture systems using different VSMC:monocyte ratios, within a degradable polyurethane scaffold, to assess their influence on ECM generation and degradation processes, and to elucidate relevant signalling molecules involved in this in vitro vascular tissue engineering system. It was found that a desired release profile of growth factors (e.g. insulin growth factor-1 (IGF-1)) and hydrolytic proteases (e.g. matrix-metalloproteinases 2, 9, 13 and 14 (MMP2, MMP9, MMP13 and MMP14)), could be achieved in co-culture systems, yielding an accumulation of ECM (specifically for 2:1 and 4:1 VSMC:monocyte culture systems). This study has significant implications for the tissue engineering field (including vascular tissue engineering), not only because it identified important cytokines and proteases that control ECM accumulation/degradation within synthetic tissue engineering scaffolds, but also because the established culture systems could be applied to improve the development of different types of tissue constructs. Sufficient extracellular matrix accumulation within cardiovascular and connective tissue engineered constructs is a prerequisite for their appropriate function in vivo. This study established co-culture systems with tissue specific cells (vascular smooth muscle cells (VSMCs)) and defined ratios of immune cells (monocytes) to investigate

Immobilization and Application of Electrospun Nanofiber Scaffold-based Growth Factor in Bone Tissue Engineering.

PubMed

Chen, Guobao; Lv, Yonggang

2015-01-01

Electrospun nanofibers have been extensively used in growth factor delivery and regenerative medicine due to many advantages including large surface area to volume ratio, high porosity, excellent loading capacity, ease of access and cost effectiveness. Their relatively large surface area is helpful for cell adhesion and growth factor loading, while storage and release of growth factor are essential to guide cellular behaviors and tissue formation and organization. In bone tissue engineering, growth factors are expected to transmit signals that stimulate cellular proliferation, migration, differentiation, metabolism, apoptosis and extracellular matrix (ECM) deposition. Bolus administration is not always an effective method for the delivery of growth factors because of their rapid diffusion from the target site and quick deactivation. Therefore, the integration of controlled release strategy within electrospun nanofibers can provide protection for growth factors against in vivo degradation, and can manipulate desired signal at an effective level with extended duration in local microenvironment to support tissue regeneration and repair which normally takes a much longer time. In this review, we provide an overview of growth factor delivery using biomimetic electrospun nanofiber scaffolds in bone tissue engineering. It begins with a brief introduction of different kinds of polymers that were used in electrospinning and their applications in bone tissue engineering. The review further focuses on the nanofiber-based growth factor delivery and summarizes the strategies of growth factors loading on the nanofiber scaffolds for bone tissue engineering applications. The perspectives on future challenges in this area are also pointed out.

Myogenic expression of an injectable protease-resistant growth hormone-releasing hormone augments long-term growth in pigs

NASA Technical Reports Server (NTRS)

Draghia-Akli, R.; Fiorotto, M. L.; Hill, L. A.; Malone, P. B.; Deaver, D. R.; Schwartz, R. J.

1999-01-01

Ectopic expression of a new serum protease-resistant porcine growth hormone-releasing hormone, directed by an injectable muscle-specific synthetic promoter plasmid vector (pSP-HV-GHRH), elicits growth in pigs. A single 10 mg intramuscular injection of pSP-HV-GHRH DNA followed by electroporation in three-week-old piglets elevated serum GHRH levels by twofold to fourfold, enhanced growth hormone secretion, and increased serum insulin-like growth factor-I by threefold to sixfold over control pigs. After 65 days the average body weight of the pigs injected with pSP-HV-GHRH was approximately 37% greater than the placebo-injected controls and resulted in a significant reduction in serum urea concentration, indicating a decrease in amino acid catabolism. Evaluation of body composition indicated a uniform increase in mass, with no organomegaly or associated pathology.

A virally inactivated functional growth factor preparation from human platelet concentrates.

PubMed

Su, C-Y; Kuo, Y P; Lin, Y C; Huang, C-T; Tseng, Y H; Burnouf, T

2009-08-01

Human platelet growth factors (HPGF) are essential for tissue regeneration and may replace fetal bovine serum (FBS) in cell therapy. No method for the manufacture of standardized virally inactivated HPGF has been developed yet. Platelet concentrates (PC) were subjected to solvent/detergent (S/D) treatment (1% TnBP/1% Triton X-45), oil extraction, hydrophobic interaction chromatography and sterile filtration. Platelet-derived growth factor (PDGF)-AB, -BB and -AA, transforming growth factor-beta1 (TGF-beta1), epidermal growth factor (EGF), insulin-like growth factor-1 (IGF-1) and vascular endothelium growth factor (VEGF) were measured by ELISA. Composition in proteins and lipids was determined, protein profiles were obtained by SDS-PAGE, and TnBP and Triton X-45 were assessed by gas chromatography and high-performance liquid chromatography, respectively. Cell growth promoting activity of HPGF was evaluated by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay using human embryonic kidney (HEK293A) fibroblast and Statens Seruminstitute rabbit corneal (SIRC) epithelial cell lines. The GF preparation contained a mean of 16.66, 2.04, 1.53, 72.19, 0.33, 48.59 and 0.44 ng/ml of PDGF-AB, -BB, -AA, TGF-beta1, EGF, IGF-1 and VEGF, respectively. The protein profile was typical of platelet releasates and had less than 2 p.p.m. of residual S/D agents. MTS assay of HEK293A and SIRC cultures showed that the GF preparation at 10% and 0.1% (v/v), respectively, could successfully replace 10% FBS for cell proliferation. Cell-stimulating activity of HPGF on HEK293A was over twice that of PC releasates. STANDARDIZED and functional virally inactivated HPGF can be prepared from human PC for possible applications in cell therapy and regenerative medicine.

Adaptive growth factor delivery from a polyelectrolyte coating promotes synergistic bone tissue repair and reconstruction

PubMed Central

Shah, Nisarg J.; Hyder, Md. Nasim; Quadir, Mohiuddin A.; Dorval Courchesne, Noémie-Manuelle; Seeherman, Howard J.; Nevins, Myron; Spector, Myron; Hammond, Paula T.

2014-01-01

Traumatic wounds and congenital defects that require large-scale bone tissue repair have few successful clinical therapies, particularly for craniomaxillofacial defects. Although bioactive materials have demonstrated alternative approaches to tissue repair, an optimized materials system for reproducible, safe, and targeted repair remains elusive. We hypothesized that controlled, rapid bone formation in large, critical-size defects could be induced by simultaneously delivering multiple biological growth factors to the site of the wound. Here, we report an approach for bone repair using a polyelectrolye multilayer coating carrying as little as 200 ng of bone morphogenetic protein-2 and platelet-derived growth factor-BB that were eluted over readily adapted time scales to induce rapid bone repair. Based on electrostatic interactions between the polymer multilayers and growth factors alone, we sustained mitogenic and osteogenic signals with these growth factors in an easily tunable and controlled manner to direct endogenous cell function. To prove the role of this adaptive release system, we applied the polyelectrolyte coating on a well-studied biodegradable poly(lactic-co-glycolic acid) support membrane. The released growth factors directed cellular processes to induce bone repair in a critical-size rat calvaria model. The released growth factors promoted local bone formation that bridged a critical-size defect in the calvaria as early as 2 wk after implantation. Mature, mechanically competent bone regenerated the native calvaria form. Such an approach could be clinically useful and has significant benefits as a synthetic, off-the-shelf, cell-free option for bone tissue repair and restoration. PMID:25136093

Enhancing human islet transplantation by localized release of trophic factors from PLG scaffolds.

PubMed

Hlavaty, K A; Gibly, R F; Zhang, X; Rives, C B; Graham, J G; Lowe, W L; Luo, X; Shea, L D

2014-07-01

Islet transplantation represents a potential cure for type 1 diabetes, yet the clinical approach of intrahepatic delivery is limited by the microenvironment. Microporous scaffolds enable extrahepatic transplantation, and the microenvironment can be designed to enhance islet engraftment and function. We investigated localized trophic factor delivery in a xenogeneic human islet to mouse model of islet transplantation. Double emulsion microspheres containing exendin-4 (Ex4) or insulin-like growth factor-1 (IGF-1) were incorporated into a layered scaffold design consisting of porous outer layers for islet transplantation and a center layer for sustained factor release. Protein encapsulation and release were dependent on both the polymer concentration and the identity of the protein. Proteins retained bioactivity upon release from scaffolds in vitro. A minimal human islet mass transplanted on Ex4-releasing scaffolds demonstrated significant improvement and prolongation of graft function relative to blank scaffolds carrying no protein, and the release profile significantly impacted the duration over which the graft functioned. Ex4-releasing scaffolds enabled better glycemic control in animals subjected to an intraperitoneal glucose tolerance test. Scaffolds releasing IGF-1 lowered blood glucose levels, yet the reduction was insufficient to achieve euglycemia. Ex4-delivering scaffolds provide an extrahepatic transplantation site for modulating the islet microenvironment to enhance islet function posttransplant. © Copyright 2014 The American Society of Transplantation and the American Society of Transplant Surgeons.

Effect of Escherichia coli and Lactobacillus rhamnosus on Macrophage Inflammatory Protein 3α, Tumor Necrosis Factor Alpha, and Transforming Growth Factor β Release by Polarized Rat Uterine Epithelial Cells in Culture

PubMed Central

Crane-Godreau, Mardi A.; Wira, Charles R.

2004-01-01

Entry of bacteria from the vagina into the uterus raises the question of uterine epithelial cell (UEC) signaling in response to the presence of bacteria. Our model system helps to define microbially elicited UEC basolateral cytokine release, important in regulating underlying stromal immune cell protection. UECs from adult rats were grown in cell culture inserts to establish a confluent polarized monolayer as was determined by transepithelial resistance (TER). Polarized epithelial cell cultures were treated apically with live or heat-killed Escherichia coli or Lactobacillus rhamnosus prior to collection of basolateral media after 24 h of incubation. Coculture of polarized UECs with live E. coli had no effect on epithelial cell TER. In response to exposure to live E. coli, epithelial cell basolateral release of macrophage inflammatory protein 3α (MIP3α) and tumor necrosis factor alpha (TNF-α) increased at a time when basolateral release of biologically active transforming growth factor β (TGF-β) decreased. Incubation of UECs with heat-killed E. coli resulted in an increased basolateral release of MIP3α and TNF-α, without affecting TER or TGF-β. In contrast to E. coli, live or heat-killed L. rhamnosus had no effect on TER or cytokine release. These studies indicate that polarized rat UECs respond to gram-negative E. coli by releasing the cytokines MIP3α and TNF-α, signals important to both the innate and adaptive immune systems. These findings suggest that UEC responses to bacteria are selective and important in initiating and regulating immune protection in the female reproductive tract. PMID:15039305

The use of autologous blood-derived growth factors in bone regeneration

PubMed Central

Civinini, Roberto; Macera, Armando; Nistri, Lorenzo; Redl, Birgit; Innocenti, Massimo

2011-01-01

Platelet-rich plasma (PRP) is defined as a portion of the plasma fraction of autologous blood having platelet concentrations above baseline. When activated the platelets release growth factors that play an essential role in bone healing such as Platelet-derived Growth Factor, Transforming Growth Factor-β, Vascular Endothelial Growth Factor and others. Multiple basic science and in vivo animal studies agree that PRP has a role in the stimulation of the healing cascade in ligament, tendon, muscle cartilage and in bone regeneration in the last years PRP had a widespread diffusion in the treatment of soft tissue and bone healing. The purpose of this review is to describe the biological properties of platelets and its factors, the methods used for producing PRP, to provide a background on the underlying basic science and an overview of evidence based medicine on clinical application of PRP in bone healing. PMID:22461800

Delivery of Alginate Scaffold Releasing Two Trophic Factors for Spinal Cord Injury Repair

PubMed Central

Grulova, I.; Slovinska, L.; Blaško, J.; Devaux, S.; Wisztorski, M.; Salzet, M.; Fournier, I.; Kryukov, O.; Cohen, S.; Cizkova, D.

2015-01-01

Spinal cord injury (SCI) has been implicated in neural cell loss and consequently functional motor and sensory impairment. In this study, we propose an alginate -based neurobridge enriched with/without trophic growth factors (GFs) that can be utilized as a therapeutic approach for spinal cord repair. The bioavailability of key GFs, such as Epidermal Growth factor (EGF) and basic Fibroblast Growth Factor (bFGF) released from injected alginate biomaterial to the central lesion site significantly enhanced the sparing of spinal cord tissue and increased the number of surviving neurons (choline acetyltransferase positive motoneurons) and sensory fibres. In addition, we document enhanced outgrowth of corticospinal tract axons and presence of blood vessels at the central lesion. Tissue proteomics was performed at 3, 7 and 10 days after SCI in rats indicated the presence of anti-inflammatory factors in segments above the central lesion site, whereas in segments below, neurite outgrowth factors, inflammatory cytokines and chondroitin sulfate proteoglycan of the lectican protein family were overexpressed. Collectively, based on our data, we confirm that functional recovery was significantly improved in SCI groups receiving alginate scaffold with affinity-bound growth factors (ALG +GFs), compared to SCI animals without biomaterial treatment. PMID:26348665

Growth hormone (GH)-releasing activity of chicken GH-releasing hormone (GHRH) in chickens.

PubMed

Harvey, S; Gineste, C; Gaylinn, B D

2014-08-01

Two peptides with sequence similarities to growth hormone releasing hormone (GHRH) have been identified by analysis of the chicken genome. One of these peptides, chicken (c) GHRH-LP (like peptide) was previously found to poorly bind to chicken pituitary membranes or to cloned and expressed chicken GHRH receptors and had little, if any, growth hormone (GH)-releasing activity in vivo or in vitro. In contrast, a second more recently discovered peptide, cGHRH, does bind to cloned and expressed cGHRH receptors and increases cAMP activity in transfected cells. The possibility that this peptide may have in vivo GH-releasing activity was therefore assessed. The intravenous (i.v.) administration of cGHRH to immature chickens, at doses of 3-100 μg/kg, significantly increased circulating GH concentrations within 10 min of injection and the plasma GH levels remained elevated for at least 30 min after the injection of maximally effective doses. The plasma GH responses to cGHRH were comparable with those induced by human (h) or porcine (p) GHRH preparations and to that induced by thyrotropin releasing hormone (TRH). In marked contrast, the i.v. injection of cGHRH-LP had no significant effect on circulating GH concentrations in immature chicks. GH release was also increased from slaughterhouse chicken pituitary glands perifused for 5 min with cGHRH at doses of 0.1 μg/ml or 1.0 μg/ml, comparable with GH responses to hGHRH1-44. In contrast, the perifusion of chicken pituitary glands with cGHRH-LP had no significant effect on GH release. In summary, these results demonstrate that cGHRH has GH-releasing activity in chickens and support the possibility that it is the endogenous ligand of the cGHRH receptor. Copyright © 2014 Elsevier Inc. All rights reserved.

E2F1 transcription factor and its impact on growth factor and cytokine signaling.

PubMed

Ertosun, Mustafa Gokhan; Hapil, Fatma Zehra; Osman Nidai, Ozes

2016-10-01

E2F1 is a transcription factor involved in cell cycle regulation and apoptosis. The transactivation capacity of E2F1 is regulated by pRb. In its hypophosphorylated form, pRb binds and inactivates DNA binding and transactivating functions of E2F1. The growth factor stimulation of cells leads to activation of CDKs (cyclin dependent kinases), which in turn phosphorylate Rb and hyperphosphorylated Rb is released from E2F1 or E2F1/DP complex, and free E2F1 can induce transcription of several genes involved in cell cycle entry, induction or inhibition of apoptosis. Thus, growth factors and cytokines generally utilize E2F1 to direct cells to either fate. Furthermore, E2F1 regulates expressions of various cytokines and growth factor receptors, establishing positive or negative feedback mechanisms. This review focuses on the relationship between E2F1 transcription factor and cytokines (IL-1, IL-2, IL-3, IL-6, TGF-beta, G-CSF, LIF), growth factors (EGF, KGF, VEGF, IGF, FGF, PDGF, HGF, NGF), and interferons (IFN-α, IFN-β and IFN-γ). Copyright © 2016 Elsevier Ltd. All rights reserved.

Media composition: growth factors.

PubMed

Hegde, Aparna; Behr, Barry

2012-01-01

Despite the fact that the fundamental principle underlying the most common method of culture media constitution is that of mimicking the natural environment of the preimplantation embryo, one major difference that remains between current embryo culture media and in vivo conditions is the absence of growth factors in vitro. Numerous growth factors are known to be present in the in vivo environment of human and nonhuman preimplantation embryos, often with peak concentrations corresponding to when fertilization and preimplantation embryo growth would occur. Although these growth factors are found in very small concentrations, they have a profound effect on tissue growth and differentiation through attachment to factor-specific receptors on cell surfaces. Receptors for many different growth factors have also been detected in human preimplantation embryos. Preimplantation embryos themselves express many growth factors. The growth factors and receptors are metabolically costly to produce, and thus their presence in the environment of the preimplantation embryo and in the embryo respectively strongly implies that embryos are designed to encounter and respond to the corresponding factors. Studies of embryo coculture also indirectly suggest that growth factors can improve in vitro development. Several animal and human studies attest to a probable beneficial effect of addition of growth factors to culture media. However, there is still ambiguity regarding the exact role of growth factors in embryonic development, the optimal dose of growth factors to be added to culture media, the combinatorial effect and endocrine of growth factors in embryonic development.

Controlled Release Strategies for Bone, Cartilage, and Osteochondral Engineering—Part II: Challenges on the Evolution from Single to Multiple Bioactive Factor Delivery

PubMed Central

Santo, Vítor E.; Mano, João F.; Reis, Rui L.

2013-01-01

The development of controlled release systems for the regeneration of bone, cartilage, and osteochondral interface is one of the hot topics in the field of tissue engineering and regenerative medicine. However, the majority of the developed systems consider only the release of a single growth factor, which is a limiting step for the success of the therapy. More recent studies have been focused on the design and tailoring of appropriate combinations of bioactive factors to match the desired goals regarding tissue regeneration. In fact, considering the complexity of extracellular matrix and the diversity of growth factors and cytokines involved in each biological response, it is expected that an appropriate combination of bioactive factors could lead to more successful outcomes in tissue regeneration. In this review, the evolution on the development of dual and multiple bioactive factor release systems for bone, cartilage, and osteochondral interface is overviewed, specifically the relevance of parameters such as dosage and spatiotemporal distribution of bioactive factors. A comprehensive collection of studies focused on the delivery of bioactive factors is also presented while highlighting the increasing impact of platelet-rich plasma as an autologous source of multiple growth factors. PMID:23249320

Sustained release of hepatocyte growth factor by cationic self-assembling peptide/heparin hybrid hydrogel improves β-cell survival and function through modulating inflammatory response

PubMed Central

Liu, Shuyun; Zhang, Lanlan; Cheng, Jingqiu; Lu, Yanrong; Liu, Jingping

2016-01-01

Inflammatory response is a major cause of grafts dysfunction in islet transplantation. Hepatocyte growth factor (HGF) had shown anti-inflammatory activity in multiple diseases. In this study, we aim to deliver HGF by self-assembling peptide/heparin (SAP/Hep) hybrid gel to protect β-cell from inflammatory injury. The morphological and slow release properties of SAPs were analyzed. Rat INS-1 β-cell line was treated with tumor necrosis factor α in vitro and transplanted into rat kidney capsule in vivo, and the viability, apoptosis, function, and inflammation of β-cells were evaluated. Cationic KLD1R and KLD2R self-assembled to nanofiber hydrogel, which showed higher binding affinity for Hep and HGF because of electrostatic interaction. Slow release of HGF from cationic SAP/Hep gel is a two-step mechanism involving binding affinity with Hep and molecular diffusion. In vitro and in vivo results showed that HGF-loaded KLD2R/Hep gel promoted β-cell survival and insulin secretion, and inhibited cell apoptosis, cytokine release, T-cell infiltration, and activation of NFκB/p38 MAPK pathways in β-cells. This study suggested that SAP/Hep gel is a promising carrier for local delivery of bioactive proteins in islet transplantation. PMID:27729786

[Growth Factors and Interleukins in Amniotic Membrane Tissue Homogenate].

PubMed

Stachon, T; Bischoff, M; Seitz, B; Huber, M; Zawada, M; Langenbucher, A; Szentmáry, N

2015-07-01

Application of amniotic membrane homogenate eye drops may be a potential treatment alternative for therapy resistant corneal epithelial defects. The purpose of this study was to determine the concentrations of epidermal growth factor (EGF), fibroblast growth factor basic (bFGF), hepatocyte growth factor (HGF), keratinocyte growth factor (KGF), interleukin-6 (IL-6) and interleukin-8 (IL-8) in amniotic membrane homogenates. Amniotic membranes of 8 placentas were prepared and thereafter stored at - 80 °C using the standard methods of the LIONS Cornea Bank Saar-Lor-Lux, Trier/Westpfalz. Following defreezing, amniotic membranes were cut in two pieces and homogenized in liquid nitrogen. One part of the homogenate was prepared in cell-lysis buffer, the other part was prepared in PBS. The tissue homogenates were stored at - 20 °C until enzyme-linked immunosorbent assay (ELISA) analysis for EGF, bFGF, HGF, KGF, IL-6 and IL-8 concentrations. Concentrations of KGF, IL-6 and IL-8 were below the detection limit using both preparation techniques. The EGF concentration in tissue homogenates treated with cell-lysis buffer (2412 pg/g tissue) was not significantly different compared to that of tissue homogenates treated with PBS (1586 pg/g tissue, p = 0.72). bFGF release was also not significantly different using cell-lysis buffer (3606 pg/g tissue) or PBS treated tissue homogenates (4649 pg/g tissue, p = 0.35). HGF release was significantly lower using cell-lysis buffer (23,555 pg/g tissue), compared to PBS treated tissue (47,766 pg/g tissue, p = 0.007). Containing EGF, bFGF and HGF, and lacking IL-6 and IL-8, the application of amniotic membrane homogenate eye drops may be a potential treatment alternative for therapy-resistant corneal epithelial defects. Georg Thieme Verlag KG Stuttgart · New York.

Extracellular Matrix (ECM) Multilayer Membrane as a Sustained Releasing Growth Factor Delivery System for rhTGF-β3 in Articular Cartilage Repair

PubMed Central

Park, Sang-Hyug; Kim, Moon Suk; Kim, Young Jick; Choi, Byung Hyune; Lee, Chun Tek; Park, So Ra; Min, Byoung-Hyun

2016-01-01

Recombinant human transforming growth factor beta-3 (rhTGF-β3) is a key regulator of chondrogenesis in stem cells and cartilage formation. We have developed a novel drug delivery system that continuously releases rhTGF-β3 using a multilayered extracellular matrix (ECM) membrane. We hypothesize that the sustained release of rhTGF-β3 could activate stem cells and result in enhanced repair of cartilage defects. The properties and efficacy of the ECM multilayer-based delivery system (EMLDS) are investigated using rhTGF-β3 as a candidate drug. The bioactivity of the released rhTGF-ß3 was evaluated through chondrogenic differentiation of mesenchymal stem cells (MSCs) using western blot and circular dichroism (CD) analyses in vitro. The cartilage reparability was evaluated through implanting EMLDS with endogenous and exogenous MSC in both in vivo and ex vivo models, respectively. In the results, the sustained release of rhTGF-ß3 was clearly observed over a prolonged period of time in vitro and the released rhTGF-β3 maintained its structural stability and biological activity. Successful cartilage repair was also demonstrated when rabbit MSCs were treated with rhTGF-β3-loaded EMLDS ((+) rhTGF-β3 EMLDS) in an in vivo model and when rabbit chondrocytes and MSCs were treated in ex vivo models. Therefore, the multilayer ECM membrane could be a useful drug delivery system for cartilage repair. PMID:27258120

Spectroscopic studies on the conformational transitions of a bovine growth hormone releasing factor analog

NASA Astrophysics Data System (ADS)

Sarver, Ronald W.; Friedman, Alan R.; Thamann, Thomas J.

1997-10-01

The secondary structure of the bovine growth hormone releasing factor analog, [Ile 2, Ser 8,28, Ala 15, Leu 27, Hse 30] bGRF(1-30)-NH-Ethyl, acetate salt (U-90699F) was studied in solution by Fourier transform infrared and Raman spectroscopies. Spectroscopic studies revealed that concentrated aqueous solutions of U-90699F (100 mg ml -1) undergo a secondary structure transition from disordered coil/α-helix to intermolecular β-sheet. Disordered coil and α-helical structure were grouped together in the infrared and Raman studies since the amide I vibrations are close in frequency and overlap in assignments was possible. Before the conformational transition, the facile exchange of the peptide's amide hydrogens for deuterium indicated that the majority of amide hydrogens were readily accessible to solvent. The kinetics of the conformational transition coincided with an increase in solution viscosity and turbidity. An initiation phase preceded the conformational transition during which only minor spectral changes were observed by infrared spectroscopy. The initiation phase and reaction kinetics were consistent with a highly cooperative nucleation ultimately leading to a network of intermolecular β-sheet structure and gel formation. Increased temperature accelerated the conformational transition. The conformational transition was thermally irreversible but the β-sheet structure of aggregated or gelled peptide could be disrupted by dilution and agitation.

Quantification of platelets and platelet derived growth factors from platelet-rich-plasma (PRP) prepared at different centrifugal force (g) and time.

PubMed

Arora, Satyam; Doda, Veena; Kotwal, Urvershi; Dogra, Mitu

2016-02-01

Platelet derived biomaterials represent a key source of cytokines and growth factors extensively used for tissue regeneration; wound healing and tissue repair. Our study was to quantify platelets and growth factors released by PRP when prepared at different centrifugal force (g) and time. Our study was approved by the institutional ethical committee. One hundred millilitres of whole blood (WB) was collected in bag with CPDA as the anticoagulant(AC); (14 mL for 100 mL WB ratio). Nine aliquots of 10 mL each were made from the bag and set of three aliquots were made a group. PRP was prepared at varying centrifugal force (group A: -110 g, group B: -208 g & group C: -440 g) & time (1: -5 min, 2: -10 min & 3: -20 min). Contents of each PRP prepared were analysed. Commercial sandwich ELISA kits were used to quantify the concentrations of CD62P (Diaclone SAS; France), Platelet derived growth factors-AB (Qayee-Bio; China), transforming growth factor-β1 (DRG; Germany) and vascular endothelial growth factor (Boster Immuno Leader; USA) released in each PRP prepared. Eight volunteers were enrolled in the study (24-30 years). The baseline blood counts of all the volunteers were comparable (p ≥ 0.05). Mean ± SD of platelet yield of all nine groups ranged from 17.2 ± 4.2% to 78.7 ± 5.7%. Each PRP was activated with calcified thromboplastin to quantify the growth factors released by them. Significantly higher (p < 0.05) transforming growth factor-β1 and vascular endothelial growth factor were released compared to the baseline. Our study highlights the variation in both force (g) and time results in changes at cellular level and growth factor concentrations. Copyright © 2016 Elsevier Ltd. All rights reserved.

Plasma growth hormone response to human growth hormone releasing factor in rats administered with chlorpromazine and antiserum against somatostatin. Effects of hypo- and hyperthyroidism.

PubMed

Wakabayashi, I; Tonegawa, Y; Ihara, T; Hattori, M; Shibasaki, T; Ling, N

1985-10-01

The effect of hypo- and hyperthyroidism on the plasma growth hormone (GH) response to synthetic human growth hormone releasing factor (GRF) was determined in conscious, freely moving rats pretreated with chlorpromazine and antiserum against somatostatin. Chlorpromazine plus somatostatin antiserum pretreated rats gave consistent response to GRF which was not observed in untreated rats. Chlorpromazine alone has no effect on GH secretion induced by GRF in rat pituitary monolayer culture. In rats made hypothyroid by thyroidectomy, both basal and peak plasma GH responses to a small (0.25 microgram/kg bw) and a moderate dose of GRF (1 microgram/kg bw) were significantly reduced as compared to controls. In rats made hyperthyroid by the administration of thyroxine, basal and peak plasma GH responses to a small but not to a moderate dose of GRF were significantly reduced as compared to controls. A reduced plasma GH response to a small dose of GRF was observed 8 days after the cessation of thyroxine administration. The pituitary GH reserve was markedly reduced in hypothyroid but not in hyperthyroid rats as compared to their respective controls. These results indicate that plasma GH response to GRF is reduced both in hypo- and hyperthyroidism. The mechanism involved in the phenomenon appears to be different between the two conditions.

Design and characteristics of cytotoxic fibroblast growth factor 1 conjugate for fibroblast growth factor receptor-targeted cancer therapy.

PubMed

Szlachcic, Anna; Zakrzewska, Malgorzata; Lobocki, Michal; Jakimowicz, Piotr; Otlewski, Jacek

2016-01-01

Fibroblast growth factor receptors (FGFRs) are attractive candidate cancer therapy targets as they are overexpressed in multiple types of tumors, such as breast, prostate, bladder, and lung cancer. In this study, a natural ligand of FGFR, an engineered variant of fibroblast growth factor 1 (FGF1V), was conjugated to a potent cytotoxic drug, monomethyl auristatin E (MMAE), and used as a targeting agent for cancer cells overexpressing FGFRs, similar to antibodies in antibody-drug conjugates. The FGF1V-valine-citrulline-MMAE conjugate showed a favorable stability profile, bound FGFRs on the cell surface specifically, and efficiently released the drug (MMAE) upon cleavage by the lysosomal protease cathepsin B. Importantly, the conjugate showed a prominent cytotoxic effect toward cell lines expressing FGFR. FGF1V-vcMMAE was highly cytotoxic at concentrations even an order of magnitude lower than those found for free MMAE. This effect was FGFR-specific as cells lacking FGFR did not show any increased mortality.

Design and characteristics of cytotoxic fibroblast growth factor 1 conjugate for fibroblast growth factor receptor-targeted cancer therapy

PubMed Central

Szlachcic, Anna; Zakrzewska, Malgorzata; Lobocki, Michal; Jakimowicz, Piotr; Otlewski, Jacek

2016-01-01

Fibroblast growth factor receptors (FGFRs) are attractive candidate cancer therapy targets as they are overexpressed in multiple types of tumors, such as breast, prostate, bladder, and lung cancer. In this study, a natural ligand of FGFR, an engineered variant of fibroblast growth factor 1 (FGF1V), was conjugated to a potent cytotoxic drug, monomethyl auristatin E (MMAE), and used as a targeting agent for cancer cells overexpressing FGFRs, similar to antibodies in antibody–drug conjugates. The FGF1V–valine–citrulline–MMAE conjugate showed a favorable stability profile, bound FGFRs on the cell surface specifically, and efficiently released the drug (MMAE) upon cleavage by the lysosomal protease cathepsin B. Importantly, the conjugate showed a prominent cytotoxic effect toward cell lines expressing FGFR. FGF1V–vcMMAE was highly cytotoxic at concentrations even an order of magnitude lower than those found for free MMAE. This effect was FGFR-specific as cells lacking FGFR did not show any increased mortality. PMID:27563235

Double emulsion electrospun nanofibers as a growth factor delivery vehicle for salivary gland regeneration

NASA Astrophysics Data System (ADS)

Foraida, Zahraa I.; Sharikova, Anna; Peerzada, Lubna N.; Khmaladze, Alexander; Larsen, Melinda; Castracane, James

2017-08-01

Sustained delivery of growth factors, proteins, drugs and other biologically active molecules is necessary for tissue engineering applications. Electrospun fibers are attractive tissue engineering scaffolds as they partially mimic the topography of the extracellular matrix (ECM). However, they do not provide continuous nourishment to the tissue. In search of a biomimetic scaffold for salivary gland tissue regeneration, we previously developed a blend nanofiber scaffold composed of the protein elastin and the synthetic polymer polylactic-co-glycolic acid (PLGA). The nanofiber scaffold promoted in vivo-like salivary epithelial cell tissue organization and apicobasal polarization. However, in order to enhance the salivary cell proliferation and biomimetic character of the scaffold, sustained growth factor delivery is needed. The composite nanofiber scaffold was optimized to act as a growth factor delivery system using epidermal growth factor (EGF) as a model protein. The nanofiber/EGF hybrid nanofibers were synthesized by double emulsion electrospinning where EGF is emulsified within a water/oil/water (w/o/w) double emulsion system. Successful incorporation of EGF was confirmed using Raman spectroscopy. EGF release profile was characterized using enzyme-linked immunosorbent assay (ELIZA) of the EGF content. Double emulsion electrospinning resulted in slower release of EGF. We demonstrated the potential of the proposed double emulsion electrospun nanofiber scaffold for the delivery of growth factors and/or drugs for tissue engineering and pharmaceutical applications.

Chronic ethanol consumption modulates growth factor release, mucosal cytokine production, and microRNA expression in nonhuman primates.

PubMed

Asquith, Mark; Pasala, Sumana; Engelmann, Flora; Haberthur, Kristen; Meyer, Christine; Park, Byung; Grant, Kathleen A; Messaoudi, Ilhem

2014-04-01

Chronic alcohol consumption has been associated with enhanced susceptibility to both systemic and mucosal infections. However, the exact mechanisms underlying this enhanced susceptibility remain incompletely understood. Using a nonhuman primate model of ethanol (EtOH) self-administration, we examined the impact of chronic alcohol exposure on immune homeostasis, cytokine, and growth factor production in peripheral blood, lung, and intestinal mucosa following 12 months of chronic EtOH exposure. EtOH exposure inhibited activation-induced production of growth factors hepatocyte growth factor (HGF), granulocyte colony-stimulating factor (G-CSF), and vascular-endothelial growth factor (VEGF) by peripheral blood mononuclear cells (PBMC). Moreover, EtOH significantly reduced the frequency of colonic Th1 and Th17 cells in a dose-dependent manner. In contrast, we did not observe differences in lymphocyte frequency or soluble factor production in the lung of EtOH-consuming animals. To uncover mechanisms underlying reduced growth factor and Th1/Th17 cytokine production, we compared expression levels of microRNAs in PBMC and intestinal mucosa. Our analysis revealed EtOH-dependent up-regulation of distinct microRNAs in affected tissues (miR-181a and miR-221 in PBMC; miR-155 in colon). Moreover, we were able to detect reduced expression of the transcription factors STAT3 and ARNT, which regulate expression of VEGF, G-CSF, and HGF and contain targets for these microRNAs. To confirm and extend these observations, PBMC were transfected with either mimics or antagomirs of miR-181 and miR-221, and protein levels of the transcription factors and growth factors were determined. Transfection of microRNA mimics led to a reduction in both STAT3/ARNT as well as VEGF/HGF/G-CSF levels. The opposite outcome was observed when microRNA antagomirs were transfected. Chronic EtOH consumption significantly disrupts both peripheral and mucosal immune homeostasis, and this dysregulation may be

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.

The course of growth response in released white spruce--10-year results

Treesearch

Robert M. Frank; Robert M. Frank

1973-01-01

Weekly bole measurements at 4.5 feet in height were made on individual codominant white spruce trees released on one, two, three, and four sides, and on untreated controls. Results showed that after 10 years annual circumference growth was still significantly related to the degree of release. The growth trend was established the first year but significant differences...

Growth differentiation factor-15 promotes glutamate release in medial prefrontal cortex of mice through upregulation of T-type calcium channels.

PubMed

Liu, Dong-Dong; Lu, Jun-Mei; Zhao, Qian-Ru; Hu, Changlong; Mei, Yan-Ai

2016-06-29

Growth differentiation factor-15 (GDF-15) has been implicated in ischemic brain injury and synapse development, but its involvement in modulating neuronal excitability and synaptic transmission remain poorly understood. In this study, we investigated the effects of GDF-15 on non-evoked miniature excitatory post-synaptic currents (mEPSCs) and neurotransmitter release in the medial prefrontal cortex (mPFC) in mice. Incubation of mPFC slices with GDF-15 for 60 min significantly increased the frequency of mEPSCs without effect on their amplitude. GDF-15 also significantly elevated presynaptic glutamate release, as shown by HPLC. These effects were blocked by dual TGF-β type I receptor (TβRI) and TGF-β type II receptor (TβRII) antagonists, but not by a TβRI antagonist alone. Meanwhile, GDF-15 enhanced pERK level, and inhibition of MAPK/ERK activity attenuated the GDF-15-induced increases in mEPSC and glutamate release. Blocking T-type calcium channels reduced the GDF-15 induced up-regulation of synaptic transmission. Membrane-protein extraction and use of an intracellular protein-transport inhibitor showed that GDF-15 promoted CaV3.1 and CaV3.3 α-subunit expression by trafficking to the membrane. These results confirm previous findings in cerebellar granule neurons, in which GDF-15 induces its neurobiological effects via TβRII and activation of the ERK pathway, providing novel insights into the mechanism of GDF-15 function in cortical neurons.

Mental illness, criminal risk factors and parole release decisions.

PubMed

Matejkowski, Jason; Draine, Jeffrey; Solomon, Phyllis; Salzer, Mark S

2011-01-01

Research has not examined whether higher rates of parole denial among inmates with mental illness (MI) are the result of the increased presence of criminal risk factors among this population. Employing a representative sample of inmates with (n  =  219) and without (n  =  184) MI receiving parole release decisions in 2007, this study tested whether the central eight risk factors for recidivism considered in parole release decisions intervened in the relationship between MI and parole release. MI was associated with possession of a substance use disorder, antisocial personality disorder and violent charges while incarcerated; however, these factors were not related to release decisions. MI was found to have neither a direct nor an indirect effect on release decisions. While results indicate that release decisions appear, to some extent, to be evidence-based, they also suggest considerable discretion is being implemented by parole board members in release decisions above and beyond consideration of criminal risk factors. Copyright © 2011 John Wiley & Sons, Ltd.

The protective effect of platelet released growth factors and bone augmentation (Bio-Oss®) on ethanol impaired osteoblasts.

PubMed

Sönmez, Tolga Taha; Bayer, Andreas; Cremer, Tillman; Hock, Jennifer Vanessa Phi; Lethaus, Bernd; Kweider, Nisreen; Wruck, Christoph Jan; Drescher, Wolf; Jahr, Holger; Lippross, Sebastian; Pufe, Thomas; Tohidnezhad, Mersedeh

2017-11-01

Chronic alcohol consumption is a known limiting factor for bone healing. One promising strategy to improve bone augmentation techniques with Bio-Oss ® in oral and maxillofacial surgery might be the supportive application of platelet-concentrated biomaterials as platelet-released growth factor (PRGF). To address this matter, we performed an in vitro study investigating the protective effects of PRGF and Bio-Oss ® in ethanol (EtOH) treated osteoblasts. The SAOS-2 osteosarcoma cell line, with and without EtOH pretreatment was used. The cell viability, proliferation and alkali phosphatase activity (ALP) after application of 0%, 5% and 10% PRGF and Bio-Oss ® were assessed. The application of PRGF and Bio-Oss ® in EtOH impaired osteoblasts showed a significant beneficial influence increasing the viability of the osteoblasts in cell culture. The synergistic effect of Bio-Oss ® and 5% PRGF on the proliferation of osteoblasts was also demonstrated. Bio-Oss ® only in combination with PRGF increases the alkaline phosphatase (ALP) activity in EtOH pretreated cells. These results indicate that the simultaneous application of PRGF and Bio-Oss ® inhibits EtOH induced bone healing impairment. Furthermore, in the cells, PRGF induced a protective mechanism which might promote bone regeneration. Copyright © 2017 Elsevier GmbH. All rights reserved.

A novel grapheme oxide-modified collagen-chitosan bio-film for controlled growth factor release in wound healing applications.

PubMed

Liu, Ting; Dan, Weihua; Dan, Nianhua; Liu, Xinhua; Liu, Xuexu; Peng, Xu

2017-08-01

Collagen-chitosan composite film modified with grapheme oxide (GO) and 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC), termed CC-G-E film, was loaded with basic fibroblast growth factor (bFGF) as the development of an efficacious wound healing device. In this study we report a novel drug delivery system that prevents the initial burst release and loss of bioactivity of drugs in vitro and in vivo applications. The results showed that CC-G-E film possessed improved thermal stability and a higher rate of crosslinking with increased mechanical properties when the dosage of GO was between 0.03% and 0.07%. It was shown that the in vitro release of bFGF from CC-G-E film continued for more than 28d. Furthermore, the CC-G-E films demonstrated excellent in vitro biocompatibility following culture with L929 fibroblasts in terms of cell adhesion and proliferation. CC-G-E films were implanted into Sprague-Dawley rats to characterize their ability to repair full-thickness skin wounds. Results showed that the CC-G-E film accelerated the wound healing process compared with the blank control. Based on all the results, it was concluded that CC-G-E film operates as a novel drug delivery system and due to its performance in wound remodeling, has potential to be developed as a wound dressing material. Copyright © 2017 Elsevier B.V. All rights reserved.

Estradiol Protects Dermal Hyaluronan/Versican Matrix during Photoaging by Release of Epidermal Growth Factor from Keratinocytes*

PubMed Central

Röck, Katharina; Meusch, Michael; Fuchs, Nikola; Tigges, Julia; Zipper, Petra; Fritsche, Ellen; Krutmann, Jean; Homey, Bernhard; Reifenberger, Julia; Fischer, Jens W.

2012-01-01

Hyaluronan (HA) and versican are key components of the dermis and are responsive to ultraviolet (UV)B-induced remodeling. The aim of this study was to explore the molecular mechanisms mediating the effects of estrogen (E2) on HA-rich extracellular matrix during photoaging. Hairless skh-1 mice were irradiated with UVB (three times, 1 minimal erythema dose (80 mJ/cm2), weekly) for 10 weeks, and endogenous sex hormone production was abrogated by ovariectomy. Subcutaneous substitution of E2 by means of controlled-release pellets caused a strong increase in the dermal HA content in both irradiated and nonirradiated skin. The increase in dermal HA correlated with induction of HA synthase HAS3 by E2. Expression of splice variant 2 of the HA-binding proteoglycan versican was also increased by E2. In search of candidate mediators of these effects, it was found that E2 strongly induced the expression of epidermal growth factor (EGF) in UVB-irradiated epidermis in vivo and in keratinocytes in vitro. EGF in turn up-regulated the expression of HAS3 and versican V2 in dermal fibroblasts. HAS3 knockdown by shRNA caused inhibition of fibroblast proliferation. Furthermore, HAS3 and versican V2 induction by E2 correlated positively with proliferation in vivo. In addition, the accumulation of inflammatory macrophages, expression of inducible cyclooxygenase 2, as well as proinflammatory monocyte chemotactic protein 1 were decreased in response to E2 in the dermis. Collectively, these data suggest that E2 treatment increases the amount of dermal HA and versican V2 via paracrine release of EGF, which may be implicated in the pro-proliferative and anti-inflammatory effects of E2 during photoaging. PMID:22493503

Diseases associated with growth hormone-releasing hormone receptor (GHRHR) mutations.

PubMed

Martari, Marco; Salvatori, Roberto

2009-01-01

The growth hormone (GH)-releasing hormone (GHRH) receptor (GHRHR) belongs to the G protein-coupled receptors family. It is expressed almost exclusively in the anterior pituitary, where it is necessary for somatotroph cells proliferation and for GH synthesis and secretion. Mutations in the human GHRHR gene (GHRHR) can impair ligand binding and signal transduction, and have been estimated to cause about 10% of autosomal recessive familial isolated growth hormone deficiency (IGHD). Mutations reported to date include five splice donor site mutations, two microdeletions, two nonsense mutations, seven missense mutations, and one mutation in the promoter. These mutations have an autosomal recessive mode of inheritance, and heterozygous individuals do not show signs of IGHD, although the presence of an intermediate phenotype has been hypothesized. Conversely, patients with biallelic mutations have low serum insulin-like growth factor-1 and GH levels (with absent or reduced GH response to exogenous stimuli), resulting--if not treated--in proportionate dwarfism. This chapter reviews the biology of the GHRHR, the mutations that affect its gene and their effects in homozygous and heterozygous individuals. Copyright © 2009 Elsevier Inc. All rights reserved.

Evidence of insulin-like growth factor binding protein-3 proteolysis during growth hormone stimulation testing.

PubMed

Nwosu, Benjamin U; Soyka, Leslie A; Angelescu, Amanda; Lee, Mary M

2011-01-01

The ternary complex is composed of insulin-like growth factor (IGF)-I, IGF binding protein (IGFBP)-3 and acid labile subunit (ALS). Growth hormone (GH) promotes IGFBP-3 proteolysis to release free IGF-I, ALS, and IGFBP-3 fragments. Our aim was to determine whether elevated GH levels during GH stimulation testing would trigger IGFBP-3 proteolysis. This prospective study of 10 short prepubertal children (height standard deviation score -2.37 +/- 0.31) used arginine and GH releasing hormone stimulation to study dynamic changes in the ternary complex moieties. IGFBP-3 was measured in two assays: a radioimmunoassay (RIA) that detects both cleaved and intact IGFBP-3; and an immunochemiluminescence assay (ICMA) that detects only intact IGFBP-3. IGFBP-3 measured by RIA increased by 19% (p < 0.05), while IGFBP-3 measured by ICMA did not significantly increase (6.1%). The significant increase in IGFBP-3 measured by RIA, but not ICMA, provides evidence of IGFBP-3 proteolysis during acute GH stimulation.

Metalloproteinase-dependent transforming growth factor-alpha release mediates neurotensin-stimulated MAP kinase activation in human colonic epithelial cells.

PubMed

Zhao, Dezheng; Zhan, Yanai; Koon, Hon Wai; Zeng, Huiyan; Keates, Sarah; Moyer, Mary P; Pothoulakis, Charalabos

2004-10-15

Expression of the neuropeptide neurotensin (NT) and its high affinity receptor (NTR1) is increased during the course of Clostridium difficile toxin A-induced acute colitis, and NTR1 antagonism attenuates the severity of toxin A-induced inflammation. We recently demonstrated in non-transformed human colonic epithelial NCM460 cells that NT treatment caused activation of a Ras-mediated MAP kinase pathway that significantly contributes to NT-induced interleukin-8 (IL-8) secretion. Here we used NCM460 cells, which normally express low levels of NTR1, and NCM460 cells stably transfected with NTR1 to identify the upstream signaling molecules involved in NT-NTR1-mediated MAP kinase activation. We found that inhibition of the epidermal growth factor receptor (EGFR) by either an EGFR neutralizing antibody or by its specific inhibitor AG1478 (0.2 microm) blocked NT-induced MAP kinase activation. Moreover, NT stimulated tyrosine phosphorylation of the EGFR, and pretreatment with a broad spectrum metalloproteinase inhibitor batimastat reduced NT-induced MAP kinase activation. Using neutralizing antibodies against the EGFR ligands EGF, heparin-binding-EGF, transforming growth factor-alpha (TGFalpha), or amphiregulin we have shown that only the anti-TGFalpha antibody significantly decreases NT-induced phosphorylation of EGFR and MAP kinases. Furthermore, inhibition of the EGF receptor by AG1478 significantly reduced NT-induced IL-8 promoter activity and IL-8 secretion. This is the first report demonstrating that NT binding to NTR1 transactivates the EGFR and that this response is linked to NT-mediated proinflammatory signaling. Our findings indicate that matrix metalloproteinase-mediated release of TGFalpha and subsequent EGFR transactivation triggers a NT-mediated MAP kinase pathway that leads to IL-8 gene expression in human colonic epithelial cells.

Insulin-like growth factor and fibroblast growth factor expression profiles in growth-restricted fetal sheep pancreas.

PubMed

Chen, Xiaochuan; Rozance, Paul J; Hay, William W; Limesand, Sean W

2012-05-01

Placental insufficiency results in intrauterine growth restriction (IUGR), impaired fetal insulin secretion and less fetal pancreatic β-cell mass, partly due to lower β-cell proliferation rates. Insulin-like growth factors (IGFs) and fibroblast growth factors (FGFs) regulate fetal β-cell proliferation and pancreas development, along with transcription factors, such as pancreatic and duodenal homeobox 1 (PDX-1). We determined expression levels for these growth factors, their receptors and IGF binding proteins in ovine fetal pancreas and isolated islets. In the IUGR pancreas, relative mRNA expression levels of IGF-I, PDX-1, FGF7 and FGFR2IIIb were 64% (P < 0.01), 76% (P < 0.05), 76% (P < 0.05) and 52% (P < 0.01) lower, respectively, compared with control fetuses. Conversely, insulin-like growth factor binding protein 2 (IGFBP-2) mRNA and protein concentrations were 2.25- and 1.2-fold greater (P < 0.05) in the IUGR pancreas compared with controls. In isolated islets from IUGR fetuses, IGF-II and IGFBP-2 mRNA concentrations were 1.5- and 3.7-fold greater (P < 0.05), and insulin mRNA was 56% less (P < 0.05) than control islets. The growth factor expression profiles for IGF and FGF signaling pathways indicate that declines in β-cell mass are due to decreased growth factor signals for both pancreatic progenitor epithelial cell and mature β-cell replication.

Placental Growth Factor Administration Abolishes Placental Ischemia-Induced Hypertension.

PubMed

Spradley, Frank T; Tan, Adelene Y; Joo, Woo S; Daniels, Garrett; Kussie, Paul; Karumanchi, S Ananth; Granger, Joey P

2016-04-01

Preeclampsia is a pregnancy-specific disorder of new-onset hypertension. Unfortunately, the most effective treatment is early delivery of the fetus and placenta. Placental ischemia appears central to the pathogenesis of preeclampsia because placental ischemia/hypoxia induced in animals by reduced uterine perfusion pressure (RUPP) or in humans stimulates release of hypertensive placental factors into the maternal circulation. The anti-angiogenic factor soluble fms-like tyrosine kinase-1 (sFlt-1), which antagonizes and reduces bioavailable vascular endothelial growth factor and placental growth factor (PlGF), is elevated in RUPP rats and preeclampsia. Although PlGF and vascular endothelial growth factor are both natural ligands for sFlt-1, vascular endothelial growth factor also has high affinity to VEGFR2 (Flk-1) causing side effects like edema. PlGF is specific for sFlt-1. We tested the hypothesis that PlGF treatment reduces placental ischemia-induced hypertension by antagonizing sFlt-1 without adverse consequences to the mother or fetus. On gestational day 14, rats were randomized to 4 groups: normal pregnant or RUPP±infusion of recombinant human PlGF (180 μg/kg per day; AG31, a purified, recombinant human form of PlGF) for 5 days via intraperitoneal osmotic minipumps. On day 19, mean arterial blood pressure and plasma sFlt-1 were higher and glomerular filtration rate lower in RUPP than normal pregnant rats. Infusion of recombinant human PlGF abolished these changes seen with RUPP along with reducing oxidative stress. These data indicate that the increased sFlt-1 and reduced PlGF resulting from placental ischemia contribute to maternal hypertension. Our novel finding that recombinant human PlGF abolishes placental ischemia-induced hypertension, without major adverse consequences, suggests a strong therapeutic potential for this growth factor in preeclampsia. © 2016 American Heart Association, Inc.

Free amino acids exhibit anthozoan "host factor" activity: they induce the release of photosynthate from symbiotic dinoflagellates in vitro.

PubMed Central

Gates, R D; Hoegh-Guldberg, O; McFall-Ngai, M J; Bil, K Y; Muscatine, L

1995-01-01

Reef-building corals and other tropical anthozoans harbor endosymbiotic dinoflagellates. It is now recognized that the dinoflagellates are fundamental to the biology of their hosts, and their carbon and nitrogen metabolisms are linked in important ways. Unlike free living species, growth of symbiotic dinoflagellates is unbalanced and a substantial fraction of the carbon fixed daily by symbiont photosynthesis is released and used by the host for respiration and growth. Release of fixed carbon as low molecular weight compounds by freshly isolated symbiotic dinoflagellates is evoked by a factor (i.e., a chemical agent) present in a homogenate of host tissue. We have identified this "host factor" in the Hawaiian coral Pocillopora damicornis as a set of free amino acids. Synthetic amino acid mixtures, based on the measured free amino acid pools of P. damicornis tissues, not only elicit the selective release of 14C-labeled photosynthetic products from isolated symbiotic dinoflagellates but also enhance total 14CO2 fixation. Images Fig. 2 PMID:11607567

Free amino acids exhibit anthozoan "host factor" activity: they induce the release of photosynthate from symbiotic dinoflagellates in vitro.

PubMed

Gates, R D; Hoegh-Guldberg, O; McFall-Ngai, M J; Bil, K Y; Muscatine, L

1995-08-01

Reef-building corals and other tropical anthozoans harbor endosymbiotic dinoflagellates. It is now recognized that the dinoflagellates are fundamental to the biology of their hosts, and their carbon and nitrogen metabolisms are linked in important ways. Unlike free living species, growth of symbiotic dinoflagellates is unbalanced and a substantial fraction of the carbon fixed daily by symbiont photosynthesis is released and used by the host for respiration and growth. Release of fixed carbon as low molecular weight compounds by freshly isolated symbiotic dinoflagellates is evoked by a factor (i.e., a chemical agent) present in a homogenate of host tissue. We have identified this "host factor" in the Hawaiian coral Pocillopora damicornis as a set of free amino acids. Synthetic amino acid mixtures, based on the measured free amino acid pools of P. damicornis tissues, not only elicit the selective release of 14C-labeled photosynthetic products from isolated symbiotic dinoflagellates but also enhance total 14CO2 fixation.

Mast Cells Synthesize, Store, and Release Nerve Growth Factor

NASA Astrophysics Data System (ADS)

Leon, A.; Buriani, A.; dal Toso, R.; Fabris, M.; Romanello, S.; Aloe, L.; Levi-Montalcini, R.

1994-04-01

Mast cells and nerve growth factor (NGF) have both been reported to be involved in neuroimmune interactions and tissue inflammation. In many peripheral tissues, mast cells interact with the innervating fibers. Changes in the behaviors of both of these elements occur after tissue injury/inflammation. As such conditions are typically associated with rapid mast cell activation and NGF accumulation in inflammatory exudates, we hypothesized that mast cells may be capable of producing NGF. Here we report that (i) NGF mRNA is expressed in adult rat peritoneal mast cells; (ii) anti-NGF antibodies clearly stain vesicular compartments of purified mast cells and mast cells in histological sections of adult rodent mesenchymal tissues; and (iii) medium conditioned by peritoneal mast cells contains biologically active NGF. Mast cells thus represent a newly recognized source of NGF. The known actions of NGF on peripheral nerve fibers and immune cells suggest that mast cell-derived NGF may control adaptive/reactive responses of the nervous and immune systems toward noxious tissue perturbations. Conversely, alterations in normal mast cell behaviors may provoke maladaptive neuroimmune tissue responses whose consequences could have profound implications in inflammatory disease states, including those of an autoimmune nature.

Compound deficiencies in multiple fibroblast growth factor signalling components differentially impact the murine gonadotrophin-releasing hormone system.

PubMed

Chung, W C J; Matthews, T A; Tata, B K; Tsai, P-S

2010-08-01

Gonadotrophin-releasing hormone (GnRH) neurones control the onset and maintenance of fertility. Aberrant development of the GnRH system underlies infertility in Kallmann syndrome [KS; idiopathic hypogonadotropic hypogonadism (IHH) and anosmia]. Some KS patients harbour mutations in the fibroblast growth factor receptor 1 (Fgfr1) and Fgf8 genes. The biological significance of these two genes in GnRH neuronal development was corroborated by the observation that GnRH neurones were severely reduced in newborn transgenic mice deficient in either gene. In the present study, we hypothesised that the compound deficiency of Fgf8 and its cognate receptors, Fgfr1 and Fgfr3, may lead to more deleterious effects on the GnRH system, thereby resulting in a more severe reproductive phenotype in patients harbouring these mutations. This hypothesis was tested by counting the number of GnRH neurones in adult transgenic mice with digenic heterozygous mutations in Fgfr1/Fgf8, Fgfr3/Fgf8 or Fgfr1/Fgfr3. Monogenic heterozygous mutations in Fgfr1, Fgf8 or Fgfr3 caused a 30-50% decrease in the total number of GnRH neurones. Interestingly, mice with digenic mutations in Fgfr1/Fgf8 showed a greater decrease in GnRH neurones compared to mice with a heterozygous defect in the Fgfr1 or Fgf8 alone. This compounding effect was not detected in mice with digenic heterozygous mutations in Fgfr3/Fgf8 or Fgfr1/Fgfr3. These results support the hypothesis that IHH/KS patients with digenic mutations in Fgfr1/Fgf8 may have a further reduction in the GnRH neuronal population compared to patients harbouring monogenic haploid mutations in Fgfr1 or Fgf8. Because only Fgfr1/Fgf8 compound deficiency leads to greater GnRH system defect, this also suggests that these fibroblast growth factor signalling components interact in a highly specific fashion to support GnRH neuronal development.

A nanoparticulate injectable hydrogel as a tissue engineering scaffold for multiple growth factor delivery for bone regeneration.

PubMed

Dyondi, Deepti; Webster, Thomas J; Banerjee, Rinti

2013-01-01

Gellan xanthan gels have been shown to be excellent carriers for growth factors and as matrices for several tissue engineering applications. Gellan xanthan gels along with chitosan nanoparticles of 297 ± 61 nm diameter, basic fibroblast growth factor (bFGF), and bone morphogenetic protein 7 (BMP7) were employed in a dual growth factor delivery system to promote the differentiation of human fetal osteoblasts. An injectable system with ionic and temperature gelation was optimized and characterized. The nanoparticle loaded gels showed significantly improved cell proliferation and differentiation due to the sustained release of growth factors. A differentiation marker study was conducted, analyzed, and compared to understand the effect of single vs dual growth factors and free vs encapsulated growth factors. Dual growth factor loaded gels showed a higher alkaline phosphatase and calcium deposition compared to single growth factor loaded gels. The results suggest that encapsulation and stabilization of growth factors within nanoparticles and gels are promising for bone regeneration. Gellan xanthan gels also showed antibacterial effects against Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis, the common pathogens in implant failure.

Tissue Factor-Factor VIIa Complex Triggers Protease Activated Receptor 2-Dependent Growth Factor Release and Migration in Ovarian Cancer

PubMed Central

Chanakira, Alice; Westmark, Pamela R.; Ong, Irene M.; Sheehan, John P.

2017-01-01

Objective Enhanced tissue factor (TF) expression in epithelial ovarian cancer (EOC) is associated with aggressive disease. Our objective was to evaluate the role of the TF-factor VIIa-protease-activated receptor-2 (PAR-2) pathway in human EOC. Methods TCGA RNAseq data from EOC databases were analyzed for PAR expression. Cell and microparticle (MP) associated TF protein expression (Western blot) and MP-associated coagulant activity were determined in human EOC (SKOV-3, OVCAR-3 and CaOV-3) and control cell lines. PAR-1 and PAR-2 protein expression were similarly examined. The PAR dependence of VEGF-A release (ELISA) and chemotactic migration in response to FVIIa and cellular proliferation in response to thrombin was evaluated with small molecule antagonists. Results Relative mRNA expression consistently demonstrated PAR-2>PAR-1≫PAR-3/4 in multiple EOC datasets. Human EOC cell line lysates confirmed expression of TF, PAR-1 and PAR-2 proteins. MPs isolated from EOC cell lines demonstrated markedly enhanced (4–10 fold) TF coagulant activity relative to control cell lines. FVIIa induced a dose-dependent increase in VEGF-A release (2.5-3 fold) from EOC cell lines that was abrogated by the PAR-2 antagonist ENMD-1068. FVIIa treatment of CaOV-3 and OVCAR-3 cells resulted in increased chemotactic migration that was abolished by ENMD-1068. Thrombin induced dose-dependent EOC cell line proliferation was completely reversed by the PAR-1 antagonist vorapaxar. Small molecule antagonists had no effect on these phenotypes without protease present. Conclusions Enhanced activity of the TF-FVIIa-PAR-2 axis may contribute to the EOC progression via PAR-2 dependent signaling that supports an angiogenic and invasive phenotype and local thrombin generation supporting PAR-1 dependent proliferation. PMID:28148395

Growth response of suppressed true fir and mountain hemlock after release.

Treesearch

K.W. Seidel

1985-01-01

The diameter and height growth of advance reproduction of suppressed true fir (Abies spp.) and mountain hemlock (Tsuga mertensiana (Bong.) Carr.) was measured in south-central Oregon after release by overstory removal in clearcuttings, shelterwood units, and uncut stands. Postrelease growth was greatest in clearcuttings,...

Prohormone convertase and autocrine growth factor mRNAs are coexpressed in small cell lung carcinoma.

PubMed

Rounseville, M P; Davis, T P

2000-08-01

A hallmark of small cell lung carcinoma (SCLC) is the expression of autocrine growth factors such as neurotensin and gastrin-releasing peptide, which bind to cellular receptors and stimulate cell division. The biological activity of autocrine growth factors requires the concurrent expression of prohormone convertases that cleave the growth factors to their active form, suggesting the expression of these genes is linked in SCLCs. RNase protection assays were used to detect the expression of autocrine growth factor and prohormone convertase mRNAs in a panel of lung cancer cell lines. These mRNAs are coexpressed in SCLC and lung carcinoid cell lines, but not in normal lung epithelium or in non-small cell lung cancers. These findings, together with earlier results from our laboratory, suggest the expression of prohormone convertases has an important role in the development and maintenance of the SCLC phenotype and that autocrine growth factor and prohormone convertase genes respond to a common transcriptional activator in SCLC.

Ultrastructure and growth factor content of equine platelet-rich fibrin gels.

PubMed

Textor, Jamie A; Murphy, Kaitlin C; Leach, J Kent; Tablin, Fern

2014-04-01

To compare fiber diameter, pore area, compressive stiffness, gelation properties, and selected growth factor content of platelet-rich fibrin gels (PRFGs) and conventional fibrin gels (FGs). PRFGs and conventional FGs prepared from the blood of 10 healthy horses. Autologous fibrinogen was used to form conventional FGs. The PRFGs were formed from autologous platelet-rich plasma of various platelet concentrations (100 × 10³ platelets/μL, 250 × 10³ platelets/μL, 500 × 10³ platelets/μL, and 1,000 × 10³ platelets/μL). All gels contained an identical fibrinogen concentration (20 mg/mL). Fiber diameter and pore area were evaluated with scanning electron microscopy. Maximum gelation rate was assessed with spectrophotometry, and gel stiffness was determined by measuring the compressive modulus. Gel weights were measured serially over 14 days as an index of contraction (volume loss). Platelet-derived growth factor-BB and transforming growth factor-β1 concentrations were quantified with ELISAs. Fiber diameters were significantly larger and mean pore areas were significantly smaller in PRFGs than in conventional FGs. Gel weight decreased significantly over time, differed significantly between PRFGs and conventional FGs, and was significantly correlated with platelet concentration. Platelet-derived growth factor-BB and transforming growth factor-β1 concentrations were highest in gels and releasates derived from 1,000 × 10³ platelets/μL. The inclusion of platelets in FGs altered the architecture and increased the growth factor content of the resulting scaffold. Platelets may represent a useful means of modifying these gels for applications in veterinary and human regenerative medicine.

Effects of hyperthyroidism and hypothyroidism on rat growth hormone release induced by thyrotropin-releasing hormone.

PubMed

Chihara, K; Kato, Y; Ohgo, S; Iwasaki, Y; Maeda, K

1976-06-01

The effect of synthetic thyrotropin-releasing hormone (TRH) on the release of growth hormone (GH) and thyroid-stimulating hormone (TSH) was investigated in euthyroid, hypothyroid, and hyperthyroid rats under urethane anesthesia. In euthyroid control rats, intravenous injection of TRH (200 ng/100 g BW) resulted in a significant increase in both plasma GH and TSH. In rats made hypothyroid by treatment with propylthiouracil or by thyroidectomy, basal GH and TSH levels were significantly elevated with exaggerated responses to TRH. In contrast, plasma GH and TSH responses to TRH were both significantly inhibited in rats made hyperthyroid by L-thyroxine (T4) treatment. These results suggest that altered thyroid status influences GH release as well as TSH secretion induced by TRH in rats.

Chronic Ethanol consumption modulates growth factor release, mucosal cytokine production and microRNA expression in nonhuman primates

PubMed Central

Asquith, Mark; Pasala, Sumana; Engelmann, Flora; Haberthur, Kristen; Meyer, Christine; Park, Byung; Grant, Kathleen A.; Messaoudi, Ilhem

2013-01-01

BACKGROUND Chronic alcohol consumption has been associated with enhanced susceptibility to both systemic and mucosal infections. However, the exact mechanisms underlying this enhanced susceptibility remain incompletely understood. METHODS Using a nonhuman primate model of ethanol self-administration, we examined the impact of chronic alcohol exposure on immune homeostasis, cytokine and growth factor production in peripheral blood, lung and intestinal mucosa following twelve months of chronic ethanol exposure. RESULTS Ethanol exposure inhibited activation-induced production of growth factors HGF, G-CSF and VEGF by peripheral blood mononuclear cells (PBMC). Moreover, ethanol significantly reduced the frequency of colonic Th1 and Th17 cells in a dose-dependent manner. In contrast, we did not observe differences in lymphocyte frequency or soluble factor production in the lung of ethanol-consuming animals. To uncover mechanisms underlying reduced growth factor and Th1/Th17 cytokine production, we compared expression levels of microRNAs in PBMC and intestinal mucosa. Our analysis revealed ethanol-dependent upregulation of distinct microRNAs in affected tissues (miR-181a and miR-221 in PBMC; miR-155 in colon). Moreover, we were able to detect reduced expression of the transcription factors STAT3 and ARNT, which regulate expression of VEGF, G-CSF and HGF and contain targets for these microRNAs. To confirm and extend these observations, PBMC were transfected with either mimics or antagomirs of miR181 and 221and protein levels of the transcription factors and growth factors were determined. Transfection of microRNA mimics led to a reduction in both STAT-3/ARNT as well as VEGF/HGF/G-CSF levels. The opposite outcome was observed when microRNA antagomirs were transfected CONCLUSION Chronic ethanol consumption significantly disrupts both peripheral and mucosal immune homeostasis, and this dysregulation may be mediated by changes in microRNA expression. PMID:24329418

Enhanced angiogenesis and osteogenesis in critical bone defects by the controlled release of BMP-2 and VEGF: implantation of electron beam melting-fabricated porous Ti6Al4V scaffolds incorporating growth factor-doped fibrin glue.

PubMed

Lv, Jia; Xiu, Peng; Tan, Jie; Jia, Zhaojun; Cai, Hong; Liu, Zhongjun

2015-06-24

Electron beam melting (EBM)-fabricated porous titanium implants possessing low elastic moduli and tailored structures are promising biomaterials for orthopedic applications. However, the bio-inert nature of porous titanium makes reinforcement with growth factors (GFs) a promising method to enhance implant in vivo performance. Bone-morphogenic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF) are key factors of angiogenesis and osteogenesis. Therefore, the present study is aimed at evaluating EBM-fabricated porous titanium implants incorporating GF-doped fibrin glue (FG) as composite scaffolds providing GFs for improvement of angiogenesis and osteogenesis in rabbit femoral condyle defects. BMP-2 and VEGF were added into the constituent compounds of FG, and then this GF-doped FG was subsequently injected into the porous scaffolds. In five groups of implants, angiogenesis and osteogenesis were evaluated at 4 weeks post-implantation using Microfil perfusion and histological analysis: eTi (empty scaffolds), cTi (containing undoped FG), BMP/cTi (containing 50 μg rhBMP-2), VEGF/cTi (containing 0.5 μg VEGF) and Dual/cTi (containing 50 μg rhBMP-2 and 0.5 μg VEGF). The results demonstrate that these composite implants are biocompatible and provide the desired gradual release of the bioactive growth factors. Incorporation of GF delivery, whether a single factor or dual factors, significantly enhanced both angiogenesis and osteogenesis inside the porous scaffolds. However, the synergistic effect of the dual factors combination was observable on angiogenesis but absent on osteogenesis. In conclusion, fibrin glue is a biocompatible material that could be employed as a delivery vehicle in EBM-fabricated porous titanium for controlled release of BMP-2 and VEGF. Application of this method for loading a porous titanium scaffold to incorporate growth factors is a convenient and promising strategy for improving osteogenesis of critical-sized bone defects.

Therapeutic effect of exogenous ghrelin in the healing of gingival ulcers is mediated by the release of endogenous growth hormone and insulin-like growth factor-1.

PubMed

Cieszkowski, J; Warzecha, Z; Ceranowicz, P; Ceranowicz, D; Kusnierz-Cabala, B; Pedziwiatr, M; Dembinski, M; Ambrozy, T; Kaczmarzyk, T; Pihut, M; Wieckiewicz, M; Olszanecki, R; Dembinski, A

2017-08-01

Ghrelin, an acylated 28-amino acid polypeptide, was primary isolated from the stomach, and the stomach is a main source of circulating ghrelin. Ghrelin strongly and dose-dependently stimulates release of growth hormone from the anterior pituitary, as well as increases food intake and fat deposition. Previous studies showed that ghrelin exhibits protective and therapeutic effect in different parts of the gastrointestinal system, including the oral cavity. The aim of present study was to examine the role of growth hormone and insulin-like growth factor-1 (IGF-1) in the healing of gingival ulcers. Studies were performed on rats with the intact pituitary gland and hypophysectomized rats. In anesthetized rats, chronic ulcers of the gum were induced by acetic acid. Rats were treated intraperitoneally twice a day with saline or ghrelin (4, 8 or 16 nmol/kg/dose) for six days. In pituitary-intact rats, administration of ghrelin significantly increased serum concentration of growth hormone and IGF-1 and this effect was associated with a significant increase in the healing rate of gingival ulcers. Moreover, treatment with ghrelin increased mucosal blood flow and DNA synthesis in the gum, while a local inflammation was decreased what was observed as a reduction in mucosal concentration of pro-inflammatory interleukin-1β. Hypophysectomy decreased serum level of growth hormone below a detection limit; whereas serum concentration of IGF-1 was reduced by 90%. On the other hand, removal of the pituitary gland was without any significant effect on the healing rate of gingival ulcers or on the ulcer-induced increase in DNA synthesis and concentration of pro-inflammatory interleukin-1β in gingival mucosa. Administration of ghrelin failed to affect serum level of growth hormone and IGF-1 in hypophysectomized rats, and was without any effect on the healing rate of gingival ulcers, mucosal blood flow, DNA synthesis or concentration of interleukin-1β in gingival mucosa. Neither

Blockade of GpIIb/IIIa inhibits the release of vascular endothelial growth factor (VEGF) from tumor cell-activated platelets and experimental metastasis.

PubMed

Amirkhosravi, A; Amaya, M; Siddiqui, F; Biggerstaff, J P; Meyer, T V; Francis, J L

1999-01-01

Evidence that platelets play a role in tumor metastasis includes the observation of circulating tumor cell-platelet aggregates and the anti-metastatic effect of thrombocytopenia and anti-platelet drugs. Platelets have recently been shown to contain vascular endothelial growth factor (VEGF) which is released during clotting. We therefore studied the effects of (1) tumor cell-platelet adherence and tumor cell TF activity on platelet VEGF release; and (2) the effects of GpIIb/IIIa blockade on tumor cell-induced platelet VEGF release, tumor cell-induced thrombocytopenia and experimental metastasis. Adherent A375 human melanoma cells (TF+) and KG1 myeloid leukemia (TF-) cells were cultured in RPMI containing 10% fetal bovine serum. Platelet-rich plasma was obtained from normal citrated whole blood and the presence of VEGF (34 and 44 kDa isoforms) confirmed by immunoblotting. Platelet-rich plasma with or without anti-GpIIb/IIIa (Abciximab) was added to A375 monolayers and supernatant VEGF measured by ELISA. Tumor cell-induced platelet activation and release were determined by CD62P expression and serotonin release respectively. In vitro, tumor cell-platelet adherence was evaluated by flow cytometry. In vivo, thrombocytopenia and lung seeding were assessed 30 min and 18 days, respectively, after i.v. injection of Lewis Lung carcinoma (LL2) cells into control or murine 7E3 F(ab')(2) (6 mg/ kg) athymic rats. Maximal in vitro platelet activation (72% serotonin release) occurred 30 min after adding platelets to tumor cells. At this time, 87% of the A375 cells had adhered to platelets. Abciximab significantly (P<0.05) reduced platelet adherence to tumor cells as evidenced by flow cytometry. Incubation of A375 cells with platelets induced VEGF release in a time-dependent manner. This release was significantly inhibited by Abciximab (81% at 30 min; P<0.05). In the presence of fibrinogen and FII, VEGF release induced by A375 (TF+) cells was significantly higher than that induced

Magnetic alginate microspheres: system for the position controlled delivery of nerve growth factor.

PubMed

Ciofani, Gianni; Raffa, Vittoria; Menciassi, Arianna; Cuschieri, Alfred; Micera, Silvestro

2009-04-01

The use of polymeric carriers containing dispersed magnetic nanocrystalline particles for targeted delivery of drugs in clinical practice has attracted the interest of the scientific community. In this paper a system comprised of alginate microparticles with a core of magnetite and carrying nerve growth factor (NGF) is described. The magnetic properties of these microspheres, typical of superparamagnetic materials, allow precise and controlled delivery to the intended tissue environment. Experiments carried out on PC12 cells with magnetic alginate microspheres loaded with NGF have confirmed the induction of cell differentiation which is strongly dependent on the distance from the microsphere cluster. In addition, finite element modelling (FEM) of the release profile from the microspheres in culture, indicated the possibility of creating defined and predictable NGF gradients from the loaded microspheres. These observations on the carriage and release of growth factors by the proposed microparticles open new therapeutic options for both neuronal regeneration and of the development of effective neuronal interfaces.

Cholangiocyte Endothelin 1 and Transforming Growth Factor β1 Production in Rat Experimental Hepatopulmonary Syndrome

PubMed Central

LUO, BAO; TANG, LIPING; WANG, ZHISHAN; ZHANG, JUNLAN; LING, YIQUN; FENG, WENGUANG; SUN, JU-ZHONG; STOCKARD, CECIL R.; FROST, ANDRA R.; CHEN, YIU-FAI; GRIZZLE, WILLIAM E.; FALLON, MICHAEL B.

2010-01-01

Background & Aims Hepatic production and release of endothelin 1 plays a central role in experimental hepatopulmonary syndrome after common bile duct ligation by stimulating pulmonary endothelial nitric oxide production. In thioacetamide-induced nonbiliary cirrhosis, hepatic endothelin 1 production and release do not occur, and hepatopulmonary syndrome does not develop. However, the source and regulation of hepatic endothelin 1 after common bile duct ligation are not fully characterized. We evaluated the sources of hepatic endothelin 1 production after common bile duct ligation in relation to thioacetamide cirrhosis and assessed whether transforming growth factor β1 regulates endothelin 1 production. Methods Hepatopulmonary syndrome and hepatic and plasma endothelin 1 levels were evaluated after common bile duct ligation or thioacetamide administration. Cellular sources of endothelin 1 were assessed by immunohistochemistry and laser capture microdissection of cholangiocytes. Transforming growth factor β1 expression and signaling were assessed by using immunohistochemistry and Western blotting and by evaluating normal rat cholangiocytes. Results Hepatic and plasma endothelin 1 levels increased and hepatopulmonary syndrome developed only after common bile duct ligation. Hepatic endothelin 1 and transforming growth factor β1 levels increased over a similar time frame, and cholangiocytes were a major source of each peptide. Transforming growth factor β1 signaling in cholangiocytes in vivo was evident by increased phosphorylation and nuclear localization of Smad2, and hepatic endothelin 1 levels correlated directly with liver transforming growth factor β1 and phosphorylated Smad2 levels. Transforming growth factor β1 also stimulated endothelin 1 promoter activity, expression, and production in normal rat cholangiocytes. Conclusions Cholangiocytes are a major source of hepatic endothelin 1 production during the development of hepatopulmonary syndrome after common

Growth Factors and Tension-Induced Skeletal Muscle Growth

NASA Technical Reports Server (NTRS)

Vandenburgh, Herman H.

1994-01-01

The project investigated biochemical mechanisms to enhance skeletal muscle growth, and developed a computer based mechanical cell stimulator system. The biochemicals investigated in this study were insulin/(Insulin like Growth Factor) IGF-1 and Steroids. In order to analyze which growth factors are essential for stretch-induced muscle growth in vitro, we developed a defined, serum-free medium in which the differentiated, cultured avian muscle fibers could be maintained for extended periods of time. The defined medium (muscle maintenance medium, MM medium) maintains the nitrogen balance of the myofibers for 3 to 7 days, based on myofiber diameter measurements and myosin heavy chain content. Insulin and IGF-1, but not IGF-2, induced pronounced myofiber hypertrophy when added to this medium. In 5 to 7 days, muscle fiber diameters increase by 71 % to 98% compared to untreated controls. Mechanical stimulation of the avian muscle fibers in MM medium increased the sensitivity of the cells to insulin and IGF-1, based on a leftward shift of the insulin dose/response curve for protein synthesis rates. (54). We developed a ligand binding assay for IGF-1 binding proteins and found that the avian skeletal muscle cultures produced three major species of 31, 36 and 43 kD molecular weight (54) Stretch of the myofibers was found to have no significant effect on the efflux of IGF-1 binding proteins, but addition of exogenous collagen stimulated IGF-1 binding protein production 1.5 to 5 fold. Steroid hormones have a profound effect on muscle protein turnover rates in vivo, with the stress-related glucocorticoids inducing rapid skeletal muscle atrophy while androgenic steroids induce skeletal muscle growth. Exercise in humans and animals reduces the catabolic effects of glucocorticoids and may enhance the anabolic effects of androgenic steroids on skeletal muscle. In our continuing work on the involvement of exogenrus growth factors in stretch-induced avian skeletal muscle growth, we

Vascular endothelial growth factor and platelet-derived growth factor are potential angiogenic and metastatic factors in human breast cancer.

PubMed

Anan, K; Morisaki, T; Katano, M; Ikubo, A; Kitsuki, H; Uchiyama, A; Kuroki, S; Tanaka, M; Torisu, M

1996-03-01

Angiogenesis is a prerequisite for tumor growth and metastasis. Tumor angiogenesis may be mediated by several angiogenic factors such as vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), transforming growth factor-alpha, and basic fibroblast growth factor. Differential mRNA expressions of VEGF, PDGF (A chain), transforming growth factor-alpha and basic fibroblast growth factor in 32 primary invasive breast tumors were examined by reverse transcriptase-polymerase chain reaction. We analyzed relationships between mRNA expressions of these angiogenic factors and the degree of angiogenesis, tumor size, and metastasis. Quantification of angiogenesis was achieved by the immunohistochemical staining of endothelial cells with antibody to CD31. VEGF and PDGF-A mRNAs were expressed more frequently in breast tumors than in nontumor breast tissues, whereas no difference was found in expression frequency of either transforming growth factor-alpha or basic fibroblast growth factor mRNA. Vascular counts in tumors correlated with each expression frequency of VEGF and PDGF-A mRNA. PDGF-A mRNA was expressed more frequently in tumors with lymph node metastasis than in those without metastasis. Expression of VEGF and PDGF mRNAs detected by reverse transcriptase-polymerase chain reaction in breast tumors correlates with tumor-related characteristics of angiogenesis and metastatic potential. Analysis of these mRNAs by reverse transcriptase-polymerase chain reaction may be useful for assessing the biologic behavior of a breast tumor before surgical treatment.

Resin-modified glass ionomer cements: fluoride release and influence on Streptococcus mutans growth.

PubMed

Friedl, K H; Schmalz, G; Hiller, K A; Shams, M

1997-02-01

The aims of the present study were to measure the fluoride release of 1 glass ionomer cement, 1 cermet, 3 resin-modified glass ionomer cements and 1 compomer, and to determine the influence of each material on bacterial growth. Test specimens were eluted in saline for 180 days. Every 2 days, the specimens were transferred into fresh saline and the fluoride content of the solution was measured. Furthermore, 48-h, 14-d, 90-d, and 180-d eluates were inoculated with Streptococcus mutans and bacterial growth was recorded nephelometrically. Fluoride release dropped significantly over time for each material with values between 6.2 (Ketac-Silver) and 29.3 (Photac-Fil) ppm after 48 h to values between 0.6 (Ketac-Silver) and 1.7 (Ketac-Fil, Vitremer) ppm after 180 days. Each material reduced bacterial growth at each time of examination, but the effect decreased significantly over time with a maximum growth of 71.7% (Ketac-Fil) to 85.6% (Ketac-Silver) after 48 h and 94.7 (Vitremer) to 99.0% (Ketac-Silver) after 180 days (growth control = 100%). Both Ketac-Silver and Dyract showed a significantly lower inhibiting effect on bacterial growth than the other materials. The tested materials showed a good correlation between fluoride release and influence on bacterial growth. However, both effects dropped dramatically over the 180-days period.

The Regulation and Function of Fibroblast Growth Factor 8 and Its Function during Gonadotropin-Releasing Hormone Neuron Development.

PubMed

Chung, Wilson C J; Linscott, Megan L; Rodriguez, Karla M; Stewart, Courtney E

2016-01-01

Over the last few years, numerous studies solidified the hypothesis that fibroblast growth factor (FGF) signaling regulates neuroendocrine progenitor cell proliferation, fate specification, and cell survival and, therefore, is critical for the regulation and maintenance of homeostasis of the body. One important example that underscores the involvement of FGF signaling during neuroendocrine cell development is gonadotropin-releasing hormone (GnRH) neuron ontogenesis. Indeed, transgenic mice with reduced olfactory placode (OP) Fgf8 expression do not have GnRH neurons. This observation indicates the requirement of FGF8 signaling for the emergence of the GnRH neuronal system in the embryonic OP, the putative birth place of GnRH neurons. Mammalian reproductive success depends on the presence of GnRH neurons to stimulate gonadotropin secretion from the anterior pituitary, which activates gonadal steroidogenesis and gametogenesis. Together, these observations are critical for understanding the function of GnRH neurons and their control of the hypothalamus-pituitary-gonadal (HPG) axis to maintain fertility. Taken together, these studies illustrate that GnRH neuron emergence and hence HPG function is vulnerable to genomic and molecular signals that abnormally modify Fgf8 expression in the developing mouse OP. In this short review, we focus on research that is aimed at unraveling how androgen, all-trans retinoic acid, and how epigenetic factors modify control mouse OP Fgf8 transcription in the context of GnRH neuronal development and mammalian reproductive success.

Dihydrotestosterone inhibits hair growth in mice by inhibiting insulin-like growth factor-I production in dermal papillae.

PubMed

Zhao, Juan; Harada, Naoaki; Okajima, Kenji

2011-10-01

We demonstrated that insulin-like growth factor-I (IGF-I) production in dermal papillae was increased and hair growth was promoted after sensory neuron stimulation in mice. Although the androgen metabolite dihydrotestosterone (DHT) inhibits hair growth by negatively modulating growth-regulatory effects of dermal papillae, relationship between androgen metabolism and IGF-I production in dermal papillae is not fully understood. We examined whether DHT inhibits IGF-I production by inhibiting sensory neuron stimulation, thereby preventing hair growth in mice. Effect of DHT on sensory neuron stimulation was examined using cultured dorsal root ganglion (DRG) neurons isolated from mice. DHT inhibits calcitonin gene-related peptide (CGRP) release from cultured DRG neurons. The non-steroidal androgen-receptor antagonist flutamide reversed DHT-induced inhibition of CGRP release. Dermal levels of IGF-I and IGF-I mRNA, and the number of IGF-I-positive fibroblasts around hair follicles were increased at 6h after CGRP administration. DHT administration for 3weeks decreased dermal levels of CGRP, IGF-I, and IGF-I mRNA in mice. Immunohistochemical expression of IGF-I and the number of proliferating cells in hair follicles were decreased and hair re-growth was inhibited in animals administered DHT. Co-administration of flutamide and CGRP reversed these changes induced by DHT administration. These observations suggest that DHT may decrease IGF-I production in dermal papillae by inhibiting sensory neuron stimulation through interaction with the androgen receptor, thereby inhibiting hair growth in mice. Copyright © 2011 Elsevier Ltd. All rights reserved.

Extracellular Matrix and Growth Factors Improve the Efficacy of Intramuscular Islet Transplantation.

PubMed

Tsuchiya, Haruyuki; Sakata, Naoaki; Yoshimatsu, Gumpei; Fukase, Masahiko; Aoki, Takeshi; Ishida, Masaharu; Katayose, Yu; Egawa, Shinichi; Unno, Michiaki

2015-01-01

The efficacy of intramuscular islet transplantation is poor despite being technically simple, safe, and associated with reduced rates of severe complications. We evaluated the efficacy of combined treatment with extracellular matrix (ECM) and growth factors in intramuscular islet transplantation. Male BALB/C mice were used for the in vitro and transplantation studies. The following three groups were evaluated: islets without treatment (islets-only group), islets embedded in ECM with growth factors (Matrigel group), and islets embedded in ECM without growth factors [growth factor-reduced (GFR) Matrigel group]. The viability and insulin-releasing function of islets cultured for 96 h were significantly improved in Matrigel and GFR Matrigel groups compared with the islets-only group. Blood glucose and serum insulin levels immediately following transplantation were significantly improved in the Matrigel and GFR Matrigel groups and remained significantly improved in the Matrigel group at postoperative day (POD) 28. On histological examination, significantly decreased numbers of TdT-mediated deoxyuridine triphosphate-biotin nick end labeling-positive islet cells and significantly increased numbers of Ki67-positive cells were observed in the Matrigel and GFR Matrigel groups at POD 3. Peri-islet revascularization was most prominent in the Matrigel group at POD 14. The efficacy of intramuscular islet transplantation was improved by combination treatment with ECM and growth factors through the inhibition of apoptosis, increased proliferation of islet cells, and promotion of revascularization.

Different Effects of Human Umbilical Cord Mesenchymal Stem Cells on Glioblastoma Stem Cells by Direct Cell Interaction or Via Released Soluble Factors.

PubMed

Bajetto, Adriana; Pattarozzi, Alessandra; Corsaro, Alessandro; Barbieri, Federica; Daga, Antonio; Bosio, Alessia; Gatti, Monica; Pisaturo, Valerio; Sirito, Rodolfo; Florio, Tullio

2017-01-01

Glioblastoma (GBM), the most common primary brain tumor in adults, is an aggressive, fast-growing and highly vascularized tumor, characterized by extensive invasiveness and local recurrence. In GBM and other malignancies, cancer stem cells (CSCs) are believed to drive invasive tumor growth and recurrence, being responsible for radio- and chemo-therapy resistance. Mesenchymal stem cells (MSCs) are multipotent progenitors that exhibit tropism for tumor microenvironment mediated by cytokines, chemokines and growth factors. Initial studies proposed that MSCs might exert inhibitory effects on tumor development, although, to date, contrasting evidence has been provided. Different studies reported either MSC anti-tumor activity or their support to tumor growth. Here, we examined the effects of umbilical cord (UC)-MSCs on in vitro GBM-derived CSC growth, by direct cell-to-cell interaction or indirect modulation, via the release of soluble factors. We demonstrate that UC-MSCs and CSCs exhibit reciprocal tropism when co-cultured as 3D spheroids and their direct cell interaction reduces the proliferation of both cell types. Contrasting effects were obtained by UC-MSC released factors: CSCs, cultured in the presence of conditioned medium (CM) collected from UC-MSCs, increased proliferation rate through transient ERK1/2 and Akt phosphorylation/activation. Analysis of the profile of the cytokines released by UC-MSCs in the CM revealed a strong production of molecules involved in inflammation, angiogenesis, cell migration and proliferation, such as IL-8, GRO, ENA-78 and IL-6. Since CXC chemokine receptor 2 (CXCR2), a receptor shared by several of these ligands, is expressed in GBM CSCs, we evaluated its involvement in CSC proliferation induced by UC-MSC-CM. Using the CXCR2 antagonist SB225002, we observed a partial but statistically significant inhibition of CSC proliferation and migration induced by the UC-MSC-released cytokines. Conversely, CXCR2 blockade did not reduce the

Methylation of bacterial release factors RF1 and RF2 is required for normal translation termination in vivo.

PubMed

Mora, Liliana; Heurgué-Hamard, Valérie; de Zamaroczy, Miklos; Kervestin, Stephanie; Buckingham, Richard H

2007-12-07

Bacterial release factors RF1 and RF2 are methylated on the Gln residue of a universally conserved tripeptide motif GGQ, which interacts with the peptidyl transferase center of the large ribosomal subunit, triggering hydrolysis of the ester bond in peptidyl-tRNA and releasing the newly synthesized polypeptide from the ribosome. In vitro experiments have shown that the activity of RF2 is stimulated by Gln methylation. The viability of Escherichia coli K12 strains depends on the integrity of the release factor methyltransferase PrmC, because K12 strains are partially deficient in RF2 activity due to the presence of a Thr residue at position 246 instead of Ala. Here, we study in vivo RF1 and RF2 activity at termination codons in competition with programmed frameshifting and the effect of the Ala-246 --> Thr mutation. PrmC inactivation reduces the specific termination activity of RF1 and RF2(Ala-246) by approximately 3- to 4-fold. The mutation Ala-246 --> Thr in RF2 reduces the termination activity in cells approximately 5-fold. After correction for the decrease in level of RF2 due to the autocontrol of RF2 synthesis, the mutation Ala-246 --> Thr reduced RF2 termination activity by approximately 10-fold at UGA codons and UAA codons. PrmC inactivation had no effect on cell growth in rich media but reduced growth considerably on poor carbon sources. This suggests that the expression of some genes needed for optimal growth under such conditions can become growth limiting as a result of inefficient translation termination.

Corticotropin-releasing factor accelerates metamorphosis in Bufo arenarum: effect on pituitary ACTH and TSH cells.

PubMed

Miranda, L A; Affanni, J M; Paz, D A

2000-04-01

The actions of several neuropeptides as hypothalamic mediators in the regulation of Bufo arenarum metamorphosis were investigated. Prometamorphic larvae were injected with 1.5 microg thyrotropin-releasing hormone (TRH), 2 microg ovine corticotropin-releasing factor (oCRF), 2 microg mammalian gonadotropin-releasing hormone (mGnRH), 2 microg human growth hormone-releasing hormone (hGHRH), or Holtfreter solution (control group). Larvae received two injections with the same dose: one at the beginning of the experiment and the other 7 days later. Several morphologic parameters (total length, tail length, wet weight, hind limb length, and metamorphic stages) were measured as indicators of growth and metamorphic development. These measurements were taken in 20 larvae per treatment or control group at the beginning of the experiment, at day 7 and at day 14 when the experiment ended. We observed that only the administration of exogenous CRF stimulated resorption of the tail and accelerated the rate of metamorphosis. In the pituitary of CRF-treated larvae we observed that thyrotropin (TSH) and adrenocorticotropic hormone (ACTH) producing cells showed a weaker immunoreactivity, a decrease in cell number and a reduction of volume density when compared with normal larvae. In conclusion, the results obtained indicate a possible role for CRF in Bufo arenarum metamorphosis. CRF may regulate interrenal and thyroid activity by acting directly upon TSH and ACTH cells. On the other hand, TRH, GnRH and GHRH were inactive in stimulating growth or metamorphosis of Bufo arenarum. J. Exp. Zool. 286:473-480, 2000. Copyright 2000 Wiley-Liss, Inc.

Epidermal growth factor- and hepatocyte growth factor-receptor activity in serum-free cultures of human hepatocytes.

PubMed

Runge, D M; Runge, D; Dorko, K; Pisarov, L A; Leckel, K; Kostrubsky, V E; Thomas, D; Strom, S C; Michalopoulos, G K

1999-02-01

Serum-free primary cultures of hepatocytes are a useful tool to study factors triggering hepatocyte proliferation and regeneration. We have developed a chemically defined serum-free system that allows human hepatocyte proliferation in the presence of epidermal growth factor and hepatocyte growth factor. DNA synthesis and accumulation were determined by [3H]thymidine incorporation and fluorometry, respectively. Western blot analyses and co-immunoprecipitations were used to investigate the association of proteins involved in epidermal growth factor and hepatocyte growth factor activation and signaling: epidermal growth factor receptor, hepatocyte growth factor receptor (MET), urokinase-type plasminogen activator and its receptor, and a member of the signal transducer and activator of transcription family, STAT-3. Primary human hepatocytes proliferated under serum-free conditions in a chemically defined medium for up to 12 days. Epidermal growth factor-receptor and MET were present and functional, decreasing over time. MET, urokinase-type plasminogen activator and urokinase-type plasminogen activator receptor co-precipitated to varying degrees during the culture period. STAT-3 co-precipitated with epidermal growth factor-receptor and MET to varying degrees. Proliferation of human hepatocytes can improve by modification of a chemically defined medium originally used for rat hepatocyte cultures. In these long-term cultures of human hepatocytes, hepatocyte growth factor and epidermal growth factor can stimulate growth and differentiation by interacting with their receptors and initiating downstream signaling. This involves complex formation of the receptors with other plasma membrane components for MET (urokinase-type plasminogen activator in context of its receptor) and activation of STAT-3 for both receptors.

Leukocyte- and platelet-rich fibrin (L-PRF) for long-term delivery of growth factor in rotator cuff repair: review, preliminary results and future directions.

PubMed

Zumstein, Matthias A; Berger, Simon; Schober, Martin; Boileau, Pascal; Nyffeler, Richard W; Horn, Michael; Dahinden, Clemens A

2012-06-01

Surgical repair of the rotator cuff repair is one of the most common procedures in orthopedic surgery. Despite it being the focus of much research, the physiological tendon-bone insertion is not recreated following repair and there is an anatomic non-healing rate of up to 94%. During the healing phase, several growth factors are upregulated that induce cellular proliferation and matrix deposition. Subsequently, this provisional matrix is replaced by the definitive matrix. Leukocyte- and platelet-rich fibrin (L-PRF) contain growth factors and has a stable dense fibrin matrix. Therefore, use of LPRF in rotator cuff repair is theoretically attractive. The aim of the present study was to determine 1) the optimal protocol to achieve the highest leukocyte content; 2) whether L-PRF releases growth factors in a sustained manner over 28 days; 3) whether standard/gelatinous or dry/compressed matrix preparation methods result in higher growth factor concentrations. 1) The standard L-PRF centrifugation protocol with 400 x g showed the highest concentration of platelets and leukocytes. 2) The L-PRF clots cultured in medium showed a continuous slow release with an increase in the absolute release of growth factors TGF-β1, VEGF and MPO in the first 7 days, and for IGF1, PDGF-AB and platelet activity (PF4=CXCL4) in the first 8 hours, followed by a decrease to close to zero at 28 days. Significantly higher levels of growth factor were expressed relative to the control values of normal blood at each culture time point. 3) Except for MPO and the TGFβ-1, there was always a tendency towards higher release of growth factors (i.e., CXCL4, IGF-1, PDGF-AB, and VEGF) in the standard/gelatinous- compared to the dry/compressed group. L-PRF in its optimal standard/gelatinous-type matrix can store and deliver locally specific healing growth factors for up to 28 days and may be a useful adjunct in rotator cuff repair.

The sludge loading rate regulates the growth and release of heterotrophic bacteria resistant to six types of antibiotics in wastewater activated sludge.

PubMed

Yuan, Qing-Bin; Guo, Mei-Ting; Yang, Jian

2015-01-01

Wastewater treatment plants are considered as hot reservoirs of antimicrobial resistance. However, the fates of antibiotic-resistant bacteria during biological treatment processes and relevant influencing factors have not been fully understood. This study evaluated the effects of the sludge loading rate on the growth and release of six kinds of antibiotic-resistant bacteria in an activated sludge system. The results indicated that higher sludge loading rates amplified the growth of all six types of antibiotic resistant bacteria. The release of most antibiotic-resistant bacteria through both the effluent and biosolids was amplified with increased sludge loading rate. Biosolids were the main pattern for all antibiotic-resistant bacteria release in an activated sludge system, which was determined primarily by their growth in the activated sludge. A higher sludge loading rate reactor tended to retain more antibiotic resistance. An activated sludge system with lower sludge loading rates was considered more conducive to the control of antibiotic resistance.

Extracellular vesicles released from mesenchymal stromal cells stimulate bone growth in osteogenesis imperfecta.

PubMed

Otsuru, Satoru; Desbourdes, Laura; Guess, Adam J; Hofmann, Ted J; Relation, Theresa; Kaito, Takashi; Dominici, Massimo; Iwamoto, Masahiro; Horwitz, Edwin M

2018-01-01

Systemic infusion of mesenchymal stromal cells (MSCs) has been shown to induce acute acceleration of growth velocity in children with osteogenesis imperfecta (OI) despite minimal engraftment of infused MSCs in bones. Using an animal model of OI we have previously shown that MSC infusion stimulates chondrocyte proliferation in the growth plate and that this enhanced proliferation is also observed with infusion of MSC conditioned medium in lieu of MSCs, suggesting that bone growth is due to trophic effects of MSCs. Here we sought to identify the trophic factor secreted by MSCs that mediates this therapeutic activity. To examine whether extracellular vesicles (EVs) released from MSCs have therapeutic activity, EVs were isolated from MSC conditioned medium by ultracentrifugation. To further characterize the trophic factor, RNA or microRNA (miRNA) within EVs was depleted by either ribonuclease (RNase) treatment or suppressing miRNA biogenesis in MSCs. The functional activity of these modified EVs was evaluated using an in vitro chondrocyte proliferation assay. Finally, bone growth was evaluated in an animal model of OI treated with EVs. We found that infusion of MSC-derived EVs stimulated chondrocyte proliferation in the growth plate, resulting in improved bone growth in a mouse model of OI. However, infusion of neither RNase-treated EVs nor miRNA-depleted EVs enhanced chondrocyte proliferation. MSCs exert therapeutic effects in OI by secreting EVs containing miRNA, and EV therapy has the potential to become a novel cell-free therapy for OI that will overcome some of the current limitations in MSC therapy. Copyright © 2017 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Oligosaccharides Released from Milk Glycoproteins Are Selective Growth Substrates for Infant-Associated Bifidobacteria

PubMed Central

Karav, Sercan; Le Parc, Annabelle; Leite Nobrega de Moura Bell, Juliana Maria; Frese, Steven A.; Kirmiz, Nina; Block, David E.; Barile, Daniela

2016-01-01

ABSTRACT Milk, in addition to nourishing the neonate, provides a range of complex glycans whose construction ensures a specific enrichment of key members of the gut microbiota in the nursing infant, a consortium known as the milk-oriented microbiome. Milk glycoproteins are thought to function similarly, as specific growth substrates for bifidobacteria common to the breast-fed infant gut. Recently, a cell wall-associated endo-β-N-acetylglucosaminidase (EndoBI-1) found in various infant-borne bifidobacteria was shown to remove a range of intact N-linked glycans. We hypothesized that these released oligosaccharide structures can serve as a sole source for the selective growth of bifidobacteria. We demonstrated that EndoBI-1 released N-glycans from concentrated bovine colostrum at the pilot scale. EndoBI-1-released N-glycans supported the rapid growth of Bifidobacterium longum subsp. infantis (B. infantis), a species that grows well on human milk oligosaccharides, but did not support growth of Bifidobacterium animalis subsp. lactis (B. lactis), a species which does not. Conversely, B. infantis ATCC 15697 did not grow on the deglycosylated milk protein fraction, clearly demonstrating that the glycan portion of milk glycoproteins provided the key substrate for growth. Mass spectrometry-based profiling revealed that B. infantis consumed 73% of neutral and 92% of sialylated N-glycans, while B. lactis degraded only 11% of neutral and virtually no (<1%) sialylated N-glycans. These results provide mechanistic support that N-linked glycoproteins from milk serve as selective substrates for the enrichment of infant-associated bifidobacteria capable of carrying out the initial deglycosylation. Moreover, released N-glycans were better growth substrates than the intact milk glycoproteins, suggesting that EndoBI-1 cleavage is a key initial step in consumption of glycoproteins. Finally, the variety of N-glycans released from bovine milk glycoproteins suggests that they may serve as

Does growth hormone releasing factor desensitize the somatotroph? Interpretation of responses of growth hormone during and after 10-hour infusion of GRF 1-29 amide in man.

PubMed

Davis, J R; Sheppard, M C; Shakespear, R A; Lynch, S S; Clayton, R N

1986-02-01

It is unclear whether growth hormone releasing factor (GRF) administration in vivo may desensitize the somatotroph. To investigate this possibility we have examined the effects of 10-h infusion of the equipotent 1-29 amide analogue of hpGRF on serum GH levels and on the subsequent GH response to a bolus dose of GRF (1-29). Four normal adult males received an intravenous infusion of 1-29 GRF (1 microgram/kg/h) from 0800 to 1800 h, with blood samples taken at 10 min intervals. A 100 micrograms intravenous bolus dose of GRF was given at 1800 h, and sampling continued for a further 90 min. GH levels were near or below the limit of detection (0.5 mU/l) throughout the control 10 h period. During GRF infusion there was increased GH release with pulses of irregular frequency and amplitude (up to 80 mU/l) continuing throughout the entire infusion period. There was no apparent reduction in total GH released towards the latter part of the infusion. On the control day, 100 micrograms GRF bolus increased mean (+/- SEM) GH from 0.82 +/- 0.21 mU/l to a peak of 59.0 +/- 44.8 mU/l (P less than 0.002). Following 10-GRF infusion, responses to bolus injection of GRF were reduced, but variable. In two subjects a small rise in GH levels occurred (basal 6.4 and 7.2 rising to peak values of 11.2 and 23.0 mU/l respectively). In the other two subjects, GH levels fell but in these the GRF bolus had coincided with a GH peak. The loss of GRF responsiveness after GRF infusion may be due to 'desensitization'.(ABSTRACT TRUNCATED AT 250 WORDS)

Prolactin, thyrotropin, and growth hormone release during stress associated with parachute jumping.

PubMed

Noel, G L; Dimond, R C; Earll, J M; Frantz, A G

1976-05-01

Prolactin, growth hormone, and thyrotropin (TSH) release during the stress of parachute jumping has been evaluated in 14 male subjects. Subjects were studied at several times before and immediately after their first military parachute jump. All three hormones had risen significantly 1 to 14 min after the jump, compared to mean levels measured immediately beforehand. Earlier studies of physical exercise by ourselves and others would suggest that emotional stress played a role in producing changes of this magnitude. We conclude that prolactin, TSH, and growth hormone are released in physiologically significant amounts in association with the stress of parachute jumping.

Comparative survival and growth of Atlantic salmon from egg stocking and fry releases

USGS Publications Warehouse

Johnson, James H.

2004-01-01

First summer survival and subsequent growth of Atlantic salmon Salmo salar planted as eggs and fry in a tributary of Cayuga Lake, New York, were examined for 3 years. Atlantic salmon were planted in December 1999-2001 in 20 Whitlock-Vibert (W-V) egg incubators, each containing 300 eyed eggs. The following May, 500 fin-clipped Atlantic salmon fry were released in the same stream section. In autumn, a backpack electroshocker was used to capture fry to assess survival and growth. Mean survival was significantly greater for fry (27.9%) than eggs (0.8%). In autumn, mean length was significantly greater for Atlantic salmon released as fry (90.1 mm) than those planted as eggs (76.2 mm), probably owing to accelerated growth in the hatchery caused by warmer water temperatures (i.e., hatchery, 9.4A?C; stream, 5.1A?C). Releasing Atlantic salmon fry in May was nearly 11 times more costly in terms of hatchery effort than was releasing eggs in December. Although the survival of Atlantic salmon eggs in W-V incubators was low, when considering production costs, the use of egg plantings may warrant consideration under certain restoration or enhancement situations.

Growth hormone-binding protein activity is inversely related to 24-hour growth hormone release in normal boys.

PubMed

Martha, P M; Rogol, A D; Blizzard, R M; Shaw, M A; Baumann, G

1991-07-01

To investigate the physiological relationship between serum GH-binding proteins and 24-h GH release, we compared the 24-h GH pulse attributes in serum samples obtained at 20-min intervals to the serum GH-binding protein activity (GH-BP) from 38 normal boys between 7 5/12 and 18 4/12 yr of age. GH-BP was determined in a serum sample from each study (containing less than 1.0 micrograms/L GH) using a standardized GH-BP assay. GH-BP results are expressed as the percentage of [125I]human GH bound to the high affinity GH-BP complex (peak II) per 160 microL serum. There were significant inverse relationships between the high affinity (receptor-related) GH-BP and several characteristics of 24-h GH release. Specifically, GH-BP was significantly (P less than 0.005 for all), but negatively, correlated with mean 24-h GH concentration (r = -0.62), sum of the GH pulse amplitudes (r = -0.57), sum of the GH pulse areas (r = -0.55), interpulse mean GH concentration (r = -0.53), and number of GH pulses per 24 h (r = -0.53). In addition, GH-BP correlated positively with the mean time interval between pulses (r = 0.59). There was also a significant positive correlation (r = 0.75; P less than 0.001) between GH-BP and the subject's age-adjusted body mass index SD score (BMI-SDS). Each characteristic of 24-h GH release correlating inversely with GH-BP also correlated inversely with BMI-SDS (P less than 0.01 for all comparisons). GH-BP did not, however, correlate with plasma insulin-like growth factor-I levels, serum testosterone concentrations, or height SDS. Binding to the low affinity GH-BP (peak I) did not correlate significantly with any of the examined GH pulse attributes, BMI-SDS, or the degree of binding to the high affinity GH-BP (peak II). We conclude that an inverse relationship exists between the high affinity serum GH-BP and 24-h GH release in boys under normal physiological conditions. We speculate that abnormalities in this relationship probably also exist and may underlie

Coupling growth-factor engineering with nanotechnology for therapeutic angiogenesis.

PubMed

Sinha Roy, Rituparna; Soni, Shivani; Harfouche, Rania; Vasudevan, Pooja R; Holmes, Oliver; de Jonge, Hugo; Rowe, Arthur; Paraskar, Abhimanyu; Hentschel, Dirk M; Chirgadze, Dimitri; Blundell, Tom L; Gherardi, Ermanno; Mashelkar, Raghunath A; Sengupta, Shiladitya

2010-08-03

Therapeutic angiogenesis is an emerging paradigm for the management of ischemic pathologies. Proangiogenic Therapy is limited, however, by the current inability to deliver angiogenic factors in a sustained manner at the site of pathology. In this study, we investigated a unique nonglycosylated active fragment of hepatocyte growth factor/scatter factor, 1K1, which acts as a potent angiogenic agent in vitro and in a zebrafish embryo and a murine matrigel implant model. Furthermore, we demonstrate that nanoformulating 1K1 for sustained release temporally alters downstream signaling through the mitogen activated protein kinase pathway, and amplifies the angiogenic outcome. Merging protein engineering and nanotechnology offers exciting possibilities for the treatment of ischemic disease, and furthermore allows the selective targeting of downstream signaling pathways, which translates into discrete phenotypes.

Ipamorelin, a new growth-hormone-releasing peptide, induces longitudinal bone growth in rats.

PubMed

Johansen, P B; Nowak, J; Skjaerbaek, C; Flyvbjerg, A; Andreassen, T T; Wilken, M; Orskov, H

1999-04-01

Ipamorelin is a new and potent synthetic pentapeptide which has distinct and specific growth hormone (GH)-releasing properties. With the objective of investigating the effects on longitudinal bone growth rate (LGR), body weight (BW), and GH release, ipamorelin in different doses (0, 18, 90 and 450 microg/day) was injected s.c. three times daily for 15 days to adult female rats. After intravital tetracycline labelling on days 0, 6, and 13, LGR was determined by measuring the distance between the respective fluorescent bands in the proximal tibia metaphysis. Ipamorelin dose-dependently increased LGR from 42 microm/day in the vehicle group to 44, 50, and 52 microm/day in the treatment groups (P<0.0001). There was also a pronounced and dose-dependent effect on BW gain. The treatment did not affect total IGF-I levels, IGFBPs, or serum markers of bone formation and resorption. The number of tartrate-resistant acid phosphatase-positive multinuclear cells in the metaphysis of the tibia did not change significantly with treatment. The responsiveness of the pituitary to a provocative i.v. dose of ipamorelin or GHRH showed that the plasma GH response was marginally reduced (P<0.03) after ipamorelin, but unchanged after GHRH. The pituitary GH content was unchanged by ipamorelin treatment. Whether ipamorelin or other GH secretagogues may have a place in the treatment of children with growth retardation requires demonstration in future clinical studies. Copyright 1999 Harcourt Publishers Ltd.

Lactoferrin release and interleukin-1, interleukin-6, and tumor necrosis factor production by human polymorphonuclear cells stimulated by various lipopolysaccharides: relationship to growth inhibition of Candida albicans.

PubMed

Palma, C; Cassone, A; Serbousek, D; Pearson, C A; Djeu, J Y

1992-11-01

Lipopolysaccharides (LPSs) from Escherichia coli, Serratia marcescens, and Salmonella typhimurium, at doses from 1 to 100 ng/ml, strongly enhanced growth inhibition of Candida albicans by human polymorphonuclear leukocytes (PMN) in vitro. Flow cytometry analysis demonstrated that LPS markedly augmented phagocytosis of Candida cells by increasing the number of yeasts ingested per neutrophil as well as the number of neutrophils capable of ingesting fungal cells. LPS activation caused augmented release of lactoferrin, an iron-binding protein which itself could inhibit the growth of C. albicans in vitro. Antibodies against lactoferrin effectively and specifically reduced the anti-C. albicans activity of both LPS-stimulated and unstimulated PMN. Northern (RNA blot) analysis showed enhanced production of mRNAs for interleukin-1 beta, tumor necrosis factor alpha, and interleukin-6 and in neutrophils within 1 h of stimulation with LPS. The cytokines were also detected in the supernatant of the activated PMN, and their synthesis was prevented by pretreatment of LPS-stimulated PMN with protein synthesis inhibitors, such as emetine and cycloheximide. These inhibitors, however, did not block either lactoferrin release or the anti-Candida activity of LPS-stimulated PMN. These results demonstrate the ability of various bacterial LPSs to augment neutrophil function against C. albicans and suggest that the release of a candidastatic, iron-binding protein, lactoferrin, may contribute to the antifungal effect of PMN. Moreover, the ability to produce cytokines upon stimulation by ubiquitous microbial products such as the endotoxins points to an extraphagocytic, immunomodulatory role of PMN during infection.

Seasonal growth and mortality of juveniles of Lampsilis fasciola (Bivalvia: Unionidae) released to a fish hatchery raceway

USGS Publications Warehouse

Hanlon, Shane D.; Neves, Richard J.

2006-01-01

Recent efforts to restore remnant or extirpated populations of freshwater mussels have focused on artificial propagation as an effective and practical conservation strategy. Although artificially cultured juveniles have been produced and released to the wild at various times of the year, no study has investigated the best time of year to release these juveniles. Newly metamorphosed juveniles of the wavyrayed lampmussel (Lampsilis fasciola) were released into a stream-fed fish hatchery raceway during March, June, and September. Growth and survival rates were measured 32, 52, 72, and 92 days post-metamorphosis. Juveniles released in June experienced the greatest growth and survival rates. Juveniles released in September and March experienced high mortality within the first month of release and exhibited poor growth in the cool water conditions typical of those seasons. Overwinter survival exhibited a size-dependent relationship.

Strategies for Controlled Delivery of Growth Factors and Cells for Bone Regeneration

PubMed Central

Vo, Tiffany N.; Kasper, F. Kurtis; Mikos, Antonios G.

2012-01-01

The controlled delivery of growth factors and cells within biomaterial carriers can enhance and accelerate functional bone formation. The carrier system can be designed with preprogrammed release kinetics to deliver bioactive molecules in a localized, spatiotemporal manner most similar to the natural wound healing process. The carrier can also act as an extracellular matrix-mimicking substrate for promoting osteoprogenitor cellular infiltration and proliferation for integrative tissue repair. This review discusses the role of various regenerative factors involved in bone healing and their appropriate combinations with different delivery systems for augmenting bone regeneration. The general requirements of protein, cell and gene therapy are described, with elaboration on how the selection of materials, configurations and processing affects growth factor and cell delivery and regenerative efficacy in both in vitro and in vivo applications for bone tissue engineering. PMID:22342771

Neonatal hyperthyroidism impairs epinephrine-provoked secretion of nerve growth factor and epidermal growth factor in mouse saliva.

PubMed

Lakshmanan, J; Landel, C P

1986-07-01

We examined long-term effects of neonatal hyperthyroidism on salivary secretions of nerve growth factor and epidermal growth factor in male and female mice at the age of 31 days. Hyperthyroidism was induced by thyroxine (T4) injections (0.4 microgram/g body weight/day) during days 0-6. Littermate control mice were treated with vehicle. T4 treatment did not alter the amounts of protein secreted into saliva but hormone administration induced alteration in the types of protein secreted. T4 treatment decreased the contents of both nerve growth factor and epidermal growth factor secreted into the saliva. A Sephadex G-200 column chromatographic profile revealed the presence of two distinct nerve growth factor immunoreactive peaks, while epidermal growth factor immunoreactivity predominantly eluted as a single low molecular weight form. T4 treatment did not alter the molecular nature of their secretion, but the treatment decreased their contents. These results indicate an impairment in salivary secretion of nerve growth factor and epidermal growth factor long after T4 treatment has been discontinued.

Microporous silk fibroin scaffolds embedding PLGA microparticles for controlled growth factor delivery in tissue engineering.

PubMed

Wenk, Esther; Meinel, Anne J; Wildy, Sarah; Merkle, Hans P; Meinel, Lorenz

2009-05-01

The development of prototype scaffolds for either direct implantation or tissue engineering purposes and featuring spatiotemporal control of growth factor release is highly desirable. Silk fibroin (SF) scaffolds with interconnective pores, carrying embedded microparticles that were loaded with insulin-like growth factor I (IGF-I), were prepared by a porogen leaching protocol. Treatments with methanol or water vapor induced water insolubility of SF based on an increase in beta-sheet content as analyzed by FTIR. Pore interconnectivity was demonstrated by SEM. Porosities were in the range of 70-90%, depending on the treatment applied, and were better preserved when methanol or water vapor treatments were prior to porogen leaching. IGF-I was encapsulated into two different types of poly(lactide-co-glycolide) microparticles (PLGA MP) using uncapped PLGA (50:50) with molecular weights of either 14 or 35 kDa to control IGF-I release kinetics from the SF scaffold. Embedded PLGA MP were located in the walls or intersections of the SF scaffold. Embedment of the PLGA MP into the scaffolds led to more sustained release rates as compared to the free PLGA MP, whereas the hydrolytic degradation of the two PLGA MP types was not affected. The PLGA types used had distinct effects on IGF-I release kinetics. Particularly the supernatants of the lower molecular weight PLGA formulations turned out to release bioactive IGF-I. Our studies justify future investigations of the developed constructs for tissue engineering applications.

Fibroblast growth factor receptors in breast cancer.

PubMed

Wang, Shuwei; Ding, Zhongyang

2017-05-01

Fibroblast growth factor receptors are growth factor receptor tyrosine kinases, exerting their roles in embryogenesis, tissue homeostasis, and development of breast cancer. Recent genetic studies have identified some subtypes of fibroblast growth factor receptors as strong genetic loci associated with breast cancer. In this article, we review the recent epidemiological findings and experiment results of fibroblast growth factor receptors in breast cancer. First, we summarized the structure and physiological function of fibroblast growth factor receptors in humans. Then, we discussed the common genetic variations in fibroblast growth factor receptors that affect breast cancer risk. In addition, we also introduced the potential roles of each fibroblast growth factor receptors isoform in breast cancer. Finally, we explored the potential therapeutics targeting fibroblast growth factor receptors for breast cancer. Based on the biological mechanisms of fibroblast growth factor receptors leading to the pathogenesis in breast cancer, targeting fibroblast growth factor receptors may provide new opportunities for breast cancer therapeutic strategies.

Released advance reproduction of white and red fir. . . growth, damage, mortality

Treesearch

Donald T. Gordon

1973-01-01

Advance reproduction of white fir and red fir released by cutting overmature over-story was studied at the Swain Mountain Experimental Forest in northern California, at 6,300 feet elevation. Seedling and sapling height growth before logging was only 0.1-0.2 foot per year. Five years after cutting, seedling and sapling height growth had accelerated to about 0.5 to 0.8...

Mediation of wound-related Rous sarcoma virus tumorigenesis by TFG (transforming growth factor)-. beta

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

Sieweke, M.H.; Bissell, M.J.; Thompson, N.L.

1990-06-29

In Rous sarcoma virus (RSV)-infected chickens, wounding leads to tumor formation with nearly 100% frequency in tissues that would otherwise remain tumor-free. Identifying molecular mediators of this phenomenon should yield important clues to the mechanisms involved in RSV tumorigenesis. Immunohistochemical staining showed that TGF-{beta} is present locally shortly after wounding, but not in unwounded controls. In addition, subcutaneous administration of recombinant transforming growth factor {beta}1 (TGF-{beta}1) could substitute completely for wounding in tumor induction. A treatment protocol of four doses of 800 nanograms of TGF-{beta} resulted in v-src-expressing tumors with 100% frequency; four doses of only 10 nanograms still ledmore » to tumor formation in 80% of the animals. This effect was specific, as other growth factors with suggested roles in would healing did not elicit the same response. Epidermal growth factor (EGF) or TGF-{alpha} had no effect, and platelet-derived growth factor (PDGF) or insulin-like growth factor-1 (IGF-1) yielded only occasional tumors after longer latency. TGF-{beta} release during the would-healing response may thus be a critical event that creates a conducive environment for RSV tumorigenesis and may act as a cofactor for transformation in this system. 31 refs., 3 figs., 2 tabs.« less

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.

Liposomal gene transfer of keratinocyte growth factor improves wound healing by altering growth factor and collagen expression.

PubMed

Pereira, Clifford T; Herndon, David N; Rocker, Roland; Jeschke, Marc G

2007-05-15

Growth factors affect the complex cascade of wound healing; however, interaction between different growth factors during dermal and epidermal regeneration are still not entirely defined. In the present study, we thought to determine the interaction between keratinocyte growth factor (KGF) administered as liposomal cDNA with other dermal and epidermal growth factors and collagen synthesis in an acute wound. Rats received an acute wound and were divided into two groups to receive weekly subcutaneous injections of liposomes plus the Lac-Z gene (0.22 microg, vehicle), or liposomes plus the KGF cDNA (2.2 microg) and Lac-Z gene (0.22 microg). Histological and immunohistochemical techniques were used to determine growth factor, collagen expression, and dermal and epidermal structure. KGF cDNA increased insulin-like growth factor-I (IGF-I), insulin-like growth factor binding protein-3 (IGFBP-3), and fibroblast growth factor (FGF), decreased transforming growth factor-beta (TGF-beta), while it had no effect on platelet-derived growth factor (PDGF) levels in the wound. KGF cDNA significantly increased collagen Type IV at both the wound edge as well as the wound bed, while it had no effect on collagen Type I and III. KGF cDNA increased re-epithelialization, improved dermal regeneration, and increased neovascularization. Exogenous administered KGF cDNA causes increases in IGF-I, IGF-BP3, FGF, and collagen IV and decreases TGF-beta concentration. KGF gene transfer accelerates wound healing without causing an increase in collagen I or III.

Impacts of environmental factors on arsenate biotransformation and release in Microcystis aeruginosa using the Taguchi experimental design approach.

PubMed

Wang, Zhenhong; Luo, Zhuanxi; Yan, Changzhou; Xing, Baoshan

2017-07-01

Very limited information is available on how and to what extent environmental factors influence arsenic (As) biotransformation and release in freshwater algae. These factors include concentrations of arsenate (As(V)), dissolved inorganic nitrogen (N), phosphate (P), and ambient pH. This study conducted a series of experiments using Taguchi methods to determine optimum conditions for As biotransformation. We assessed principal effective factors of As(V), N, P, and pH and determined that As biotransformation and release actuate at 10.0 μM As(V) in dead alga cells, the As efflux ratio and organic As efflux content actuate at 1.0 mg/L P, algal growth and intracellular arsenite (As(III)) content actuate at 10.0 mg/L N, and the total sum of As(III) efflux from dead alga cells actuates at a pH level of 10. Moreover, N is the critical component for As(V) biotransformation in M. aeruginosa, specifically for As(III) transformation, because N can accelerate algal growth, subsequently improving As(III) accumulation and its efflux, which results in an As(V) to As(III) reduction. Furthermore, low P concentrations in combination with high N concentrations promote As accumulation. Following As(V), P was the primary impacting factor for As accumulation. In addition, small amounts of As accumulation under low concentrations of As and high P were securely stored in living algal cells and were easily released after cell death. Results from this study will help to assess practical applications and the overall control of key environmental factors, particularly those associated with algal bioremediation in As polluted water. Copyright © 2017 Elsevier Ltd. All rights reserved.

Different Effects of Human Umbilical Cord Mesenchymal Stem Cells on Glioblastoma Stem Cells by Direct Cell Interaction or Via Released Soluble Factors

PubMed Central

Bajetto, Adriana; Pattarozzi, Alessandra; Corsaro, Alessandro; Barbieri, Federica; Daga, Antonio; Bosio, Alessia; Gatti, Monica; Pisaturo, Valerio; Sirito, Rodolfo; Florio, Tullio

2017-01-01

Glioblastoma (GBM), the most common primary brain tumor in adults, is an aggressive, fast-growing and highly vascularized tumor, characterized by extensive invasiveness and local recurrence. In GBM and other malignancies, cancer stem cells (CSCs) are believed to drive invasive tumor growth and recurrence, being responsible for radio- and chemo-therapy resistance. Mesenchymal stem cells (MSCs) are multipotent progenitors that exhibit tropism for tumor microenvironment mediated by cytokines, chemokines and growth factors. Initial studies proposed that MSCs might exert inhibitory effects on tumor development, although, to date, contrasting evidence has been provided. Different studies reported either MSC anti-tumor activity or their support to tumor growth. Here, we examined the effects of umbilical cord (UC)-MSCs on in vitro GBM-derived CSC growth, by direct cell-to-cell interaction or indirect modulation, via the release of soluble factors. We demonstrate that UC-MSCs and CSCs exhibit reciprocal tropism when co-cultured as 3D spheroids and their direct cell interaction reduces the proliferation of both cell types. Contrasting effects were obtained by UC-MSC released factors: CSCs, cultured in the presence of conditioned medium (CM) collected from UC-MSCs, increased proliferation rate through transient ERK1/2 and Akt phosphorylation/activation. Analysis of the profile of the cytokines released by UC-MSCs in the CM revealed a strong production of molecules involved in inflammation, angiogenesis, cell migration and proliferation, such as IL-8, GRO, ENA-78 and IL-6. Since CXC chemokine receptor 2 (CXCR2), a receptor shared by several of these ligands, is expressed in GBM CSCs, we evaluated its involvement in CSC proliferation induced by UC-MSC-CM. Using the CXCR2 antagonist SB225002, we observed a partial but statistically significant inhibition of CSC proliferation and migration induced by the UC-MSC-released cytokines. Conversely, CXCR2 blockade did not reduce the

Crown Release Increases Diameter Growth and Bole Sprouting of Pole-Size Yellow Birch

Treesearch

Gayne G. Erdmann; Ralph M. Jr. Peterson

1971-01-01

During the second and third years after release, dominant, codominant, and intermediate pole-size yellow birch grew nearly twice as fast in diameter as unreleased poles. Growth rates were also related to foliage density. Epicormic sprouting was increased by crown release but most sprouting occured in the second log.

Structural Variability of Tropospheric Growth Factors Transforming Mid-latitude Cyclones to Severe Storms over the North Atlantic

NASA Astrophysics Data System (ADS)

Wild, Simon; Befort, Daniel J.; Leckebusch, Gregor C.

2015-04-01

The development of European surface wind storms out of normal mid-latitude cyclones is substantially influenced by upstream tropospheric growth factors over the Northern Atlantic. The main factors include divergence and vorticity advection in the upper troposphere, latent heat release and the presence of instabilities of short baroclinic waves of suitable wave lengths. In this study we examine a subset of these potential growth factors and their related influences on the transformation of extra-tropical cyclones into severe damage prone surface storm systems. Previous studies have shown links between specific growth factors and surface wind storms related to extreme cyclones. In our study we investigate in further detail spatial and temporal variability patterns of these upstream processes at different vertical levels of the troposphere. The analyses will comprise of the three growth factors baroclinicity, latent heat release and upper tropospheric divergence. Our definition of surface wind storms is based on the Storm Severity Index (SSI) alongside a wind tracking algorithm identifying areas of exceedances of the local 98th percentile of the 10m wind speed. We also make use of a well-established extra-tropical cyclone identification and tracking algorithm. These cyclone tracks form the base for a composite analysis of the aforementioned growth factors using ERA-Interim Reanalysis from 1979 - 2014 for the extended winter season (ONDJFM). Our composite analysis corroborates previous similar studies but extends them by using an impact based algorithm for the identification of strong wind systems. Based on this composite analysis we further identify variability patterns for each growth factor most important for the transformation of a cyclone into a surface wind storm. We thus also address the question whether the link between storm intensity and related growth factor anomaly taking into account its spatial variability is stable and can be quantified. While the

Endurance exercise modulates levodopa induced growth hormone release in patients with Parkinson's disease.

PubMed

Müller, Thomas; Welnic, Jacub; Woitalla, Dirk; Muhlack, Siegfried

2007-07-11

Acute levodopa (LD) application and exercise release human growth hormone (GH). An earlier trial showed, that combined stimulus of exercise and LD administration is the best provocative test for GH response in healthy participants. Objective was to show this combined effect of LD application and exercise on GH response and to investigate the impact on LD metabolism in 20 previously treated patients with Parkinson's disease (PD). We measured GH- and LD plasma concentrations following soluble 200 mg LD/50 mg benserazide administration during endurance exercise and rest on two separate consecutive days. GH concentrations significantly increased on both days, but GH release was significantly delayed during rest. LD metabolism was not altered due to exercise in a clinical relevant manner. Exercise induced a significant faster LD stimulated GH release in comparison with the rest condition. We did not find the supposed increase of LD induced GH release by endurance exercise. We assume, that only a limited amount of GH is available for GH release in the anterior pituitary following an acute 200 mg LD administration. GH disposal also depends on growth hormone releasing hormone (GHRH), which is secreted into hypothalamic portal capillaries. During the exercise condition, the resulting higher blood pressure supports blood flow and thus GHRH transport towards the GH producing cells in the pituitary. This might additionally have caused the significant faster GH release during exercise.

Evaluation of Autologous Fascia Implantation With Controlled Release of Fibroblast Growth Factor for Recurrent Laryngeal Nerve Paralysis Due to Long-term Denervation.

PubMed

Nagai, Hiromi; Nishiyama, Koichiro; Seino, Yutomo; Tabata, Yasuhiko; Okamoto, Makito

2016-06-01

Paralyzed tissue due to long-term denervation is resistant to many treatments because it induces irreversible histological changes and disorders of deglutition or phonation. We sought to determine the effect of autologous transplantation of fascia into the vocal fold (ATFV) with controlled release of basic fibroblast growth factor (bFGF) on long-term unilateral vocal fold paralysis (UVFP). Unilateral recurrent laryngeal nerve (RLN) section was performed on 20 rats. Five rats were implanted with autologous fascia only (fascia group), and 10 rats were implanted with autologous fascia and a gelatin hydrogel sheet with 1 μg (1 μg bFGF + fascia group) or 0.1 μg (0.1 μg bFGF + fascia group) of bFGF 4 months after RLN section. We evaluated the normalized glottal gap and laryngeal volume and histological changes 3 months after implantation. The normalized glottal gap was significantly reduced in the 3 fascia implantation groups. Normalized laryngeal volume, fat volume, and lateral thyroarytenoid muscle volume were significantly increased in the 2 fascia implantation with bFGF groups. The ATFV with controlled release of bFGF repaired the glottal gap and laryngeal volume after RLN section and may reduce the occurrence of aspiration and hoarseness. We speculate that this treatment improves laryngeal function in long-term RLN denervation. © The Author(s) 2016.

Platelet released growth factors boost expansion of bone marrow derived CD34(+) and CD133(+) endothelial progenitor cells for autologous grafting.

PubMed

Lippross, Sebastian; Loibl, Markus; Hoppe, Sven; Meury, Thomas; Benneker, Lorin; Alini, Mauro; Verrier, Sophie

2011-01-01

Stem cell based autologous grafting has recently gained mayor interest in various surgical fields for the treatment of extensive tissue defects. CD34(+) and CD133(+) cells that can be isolated from the pool of bone marrow mononuclear cells (BMC) are capable of differentiating into mature endothelial cells in vivo. These endothelial progenitor cells (EPC) are believed to represent a major portion of the angiogenic regenerative cells that are released from bone marrow when tissue injury has occurred. In recent years tissue engineers increasingly looked at the process of vessel neoformation because of its major importance for successful cell grafting to replace damaged tissue. Up to now one of the greatest problems preventing a clinical application is the large scale of expansion that is required for such purpose. We established a method to effectively enhance the expansion of CD34(+) and CD133(+) cells by the use of platelet-released growth factors (PRGF) as a media supplement. PRGF were prepared from thrombocyte concentrates and used as a media supplement to iscove's modified dulbecco's media (IMDM). EPC were immunomagnetically separated from human bone morrow monocyte cells and cultured in IMDM + 10% fetal calf serum (FCS), IMDM + 5%, FCS + 5% PRGF and IMDM + 10% PRGF. We clearly demonstrate a statistically significant higher and faster cell proliferation rate at 7, 14, 21, and 28 days of culture when both PRGF and FCS were added to the medium as opposed to 10% FCS or 10% PRGF alone. The addition of 10% PRGF to IMDM in the absence of FCS leads to a growth arrest from day 14 on. In histochemical, immunocytochemical, and gene-expression analysis we showed that angiogenic and precursor markers of CD34(+) and CD133(+) cells are maintained during long-term culture. In summary, we established a protocol to boost the expansion of CD34(+) and CD133(+) cells. Thereby we provide a technical step towards the clinical application of autologous stem cell

New microbial growth factor

NASA Technical Reports Server (NTRS)

Bok, S. H.; Casida, L. E., Jr.

1977-01-01

A screening procedure was used to isolate from soil a Penicillium sp., two bacterial isolates, and a Streptomyces sp. that produced a previously unknown microbial growth factor. This factor was an absolute growth requirement for three soil bacteria. The Penicillium sp. and one of the bacteria requiring the factor, an Arthrobacter sp., were selected for more extensive study concerning the production and characteristics of the growth factor. It did not seem to be related to the siderochromes. It was not present in soil extract, rumen fluid, or any other medium component tested. It appears to be a glycoprotein of high molecular weight and has high specific activity. When added to the diets for a meadow-vole mammalian test system, it caused an increased consumption of diet without a concurrent increase in rate of weight gain.

Cardioprotective effects of growth hormone-releasing hormone agonist after myocardial infarction

PubMed Central

Kanashiro-Takeuchi, Rosemeire M.; Tziomalos, Konstantinos; Takeuchi, Lauro M.; Treuer, Adriana V.; Lamirault, Guillaume; Dulce, Raul; Hurtado, Michael; Song, Yun; Block, Norman L.; Rick, Ferenc; Klukovits, Anna; Hu, Qinghua; Varga, Jozsef L.; Schally, Andrew V.; Hare, Joshua M.

2010-01-01

Whether the growth hormone (GH)/insulin-like growth factor 1(IGF-1) axis exerts cardioprotective effects remains controversial; and the underlying mechanism(s) for such actions are unclear. Here we tested the hypothesis that growth hormone-releasing hormone (GHRH) directly activates cellular reparative mechanisms within the injured heart, in a GH/IGF-1 independent fashion. After experimental myocardial infarction (MI), rats were randomly assigned to receive, during a 4-week period, either placebo (n = 14), rat recombinant GH (n = 8) or JI-38 (n = 8; 50 µg/kg per day), a potent GHRH agonist. JI-38 did not elevate serum levels of GH or IGF-1, but it markedly attenuated the degree of cardiac functional decline and remodeling after injury. In contrast, GH administration markedly elevated body weight, heart weight, and circulating GH and IGF-1, but it did not offset the decline in cardiac structure and function. Whereas both JI-38 and GH augmented levels of cardiac precursor cell proliferation, only JI-38 increased antiapoptotic gene expression. The receptor for GHRH was detectable on myocytes, supporting direct activation of cardiac signal transduction. Collectively, these findings demonstrate that within the heart, GHRH agonists can activate cardiac repair after MI, suggesting the existence of a potential signaling pathway based on GHRH in the heart. The phenotypic profile of the response to a potent GHRH agonist has therapeutic implications. PMID:20133784

[Effects of crop tree release on stand growth and stand structure of Cunninghamia lanceolata plantation].

PubMed

Wu, Jian-qiang; Wang, Yi-xiang; Yang, Yi; Zhu, Ting-ting; Zhu, Xu-dan

2015-02-01

Crop trees were selected in a 26-year-old even-aged Cunninghamia lanceolata plantation in Lin' an, and compared in plots that were released and unreleased to examine growth and structure responses for 3 years after thinning. Crop tree release significantly increased the mean increments of diameter and volume of individual tree by 1.30 and 1.25 times relative to trees in control stands, respectively. The increments of diameter and volume of crop trees were significantly higher than those of general trees in thinning plots, crop trees and general trees in control plots, which suggested that the responses from different tree types to crop tree release treatment were different. Crop tree release increased the average distances of crop trees to the nearest neighboring trees, reducing competition among crop trees by about 68.2%. 3-year stand volume increment for thinning stands had no significant difference with that of control stands although the number of trees was only 81.5% of the control. Crop trees in thinned plots with diameters over than 14 cm reached 18.0% over 3 years, compared with 12.0% for trees without thinning, suggesting that crop tree release benefited the larger individual trees. The pattern of tree locations in thinning plots tended to be random, complying with the rule that tree distribution pattern changes with growth. Crop tree release in C. lanceolata plantation not only promoted the stand growth, but also optimized the stand structure, benefiting crop trees sustained rapid growth and larger diameter trees production.

High molecular weight FGF2: the biology of a nuclear growth factor

PubMed Central

Chlebova, K.; Bryja, V.; Dvorak, P.; Kozubik, A.; Wilcox, W. R.

2011-01-01

Fibroblast growth factor 2 (FGF2) is one of the most studied growth factors to date. Most attention has been dedicated to the smallest, 18kDa FGF2 variant that is released by cells and acts through activation of cell-surface FGF-receptor tyrosine kinases. There are, however, several higher molecular weight (HMW) variants of FGF2 that rarely leave their producing cells, are retained in the nucleus and act independently of FGF-receptors (FGFR). Despite significant evidence documenting the expression and intracellular trafficking of HMW FGF2, many important questions remain about the physiological roles and mechanisms of action of HMW FGF2. In this review, we summarize the current knowledge about the biology of HMW FGF2, its role in disease and areas for future investigation. PMID:18850066

Effects of crown release on growth and quality of even-aged red maple stands

Treesearch

Terry F. Strong; Audra E. Hubbell; Adam H. Weise; Gayne G. Erdmann

2006-01-01

The effects of six crown-release treatments on growth and bole quality of 54 dominant, codominant, and intermediate red maples (Acer rubrum L.) were examined in an even-aged stand in upper Michigan. Treatments included an unreleased control, a single-tree and a two-tree crown release, and a full crown-to-crown release of 5, 10, and 15ft. Twenty-two...

Factors That Influence Language Growth.

ERIC Educational Resources Information Center

McCarthy, Dorothea, Ed.; And Others

This booklet contains four articles that discuss factors influencing language growth. The first, "The Child's Equipment for Language Growth" by Charlotte Wells, examines what the child needs for language learning, how the child uses his equipment for language growth, and what school factors facilitate the child's use of his equipment for language…

A Prodomain Fragment from the Proteolytic Activation of Growth Differentiation Factor 11 Remains Associated with the Mature Growth Factor and Keeps It Soluble.

PubMed

Pepinsky, Blake; Gong, Bang-Jian; Gao, Yan; Lehmann, Andreas; Ferrant, Janine; Amatucci, Joseph; Sun, Yaping; Bush, Martin; Walz, Thomas; Pederson, Nels; Cameron, Thomas; Wen, Dingyi

2017-08-22

Growth differentiation factor 11 (GDF11), a member of the transforming growth factor β (TGF-β) family, plays diverse roles in mammalian development. It is synthesized as a large, inactive precursor protein containing a prodomain, pro-GDF11, and exists as a homodimer. Activation requires two proteolytic processing steps that release the prodomains and transform latent pro-GDF11 into active mature GDF11. In studying proteolytic activation in vitro, we discovered that a 6-kDa prodomain peptide containing residues 60-114, PDP 60-114 , remained associated with the mature growth factor. Whereas the full-length prodomain of GDF11 is a functional antagonist, PDP 60-114 had no impact on activity. The specific activity of the GDF11/PDP 60-114 complex (EC 50 = 1 nM) in a SMAD2/3 reporter assay was identical to that of mature GDF11 alone. PDP 60-114 improved the solubility of mature GDF11 at neutral pH. As the growth factor normally aggregates/precipitates at neutral pH, PDP 60-114 can be used as a solubility-enhancing formulation. Expression of two engineered constructs with PDP 60-114 genetically fused to the mature domain of GDF11 through a 2x or 3x G4S linker produced soluble monomeric products that could be dimerized through redox reactions. The construct with a 3x G4S linker retained 10% activity (EC 50 = 10 nM), whereas the construct connected with a 2x G4S linker could only be activated (EC 50 = 2 nM) by protease treatment. Complex formation with PDP 60-114 represents a new strategy for stabilizing GDF11 in an active state that may translate to other members of the TGF-β family that form latent pro/mature domain complexes.

A review of the influence of growth factors and cytokines in in vitro human keratinocyte migration.

PubMed

Peplow, Philip V; Chatterjee, Marissa P

2013-04-01

Keratinocyte migration from the wound edge is a crucial step in the reepithelization of cutaneous wounds. Growth factors and cytokines, released from cells that invade the wound matrix, play an important role, and several in vitro assays have been performed to elucidate this. The purposes of this study were to review in vitro human studies on keratinocyte migration to identify those growth factors or cytokines that stimulate keratinocyte migration and whether these assays might serve as a screening procedure prior to testing combinations of growth factors or cytokines to promote wound closure in vivo. Research papers investigating effect of growth factors and cytokines on human keratinocyte migration in vitro were retrieved from library sources, PubMed databases, reference lists of papers, and searches of relevant journals. Fourteen different growth factors and cytokines enhanced migration in scratch wound assay and HGF together with TGF-β, and IGF-1 with EGF, were more stimulatory than either growth factor alone. HGF with TGF-β1 had a greater chemokinetic effect than either growth factor alone in transmigration assay. TGF-β1, FGF-7, FGF-2 and AGF were chemotactic to keratinocytes. EGF, TGF-α, IL-1α, IGF and MGSA enhanced cell migration on ECM proteins. Many growth factors and cytokines enhanced migration of keratinocytes in vitro, and certain combinations of growth factors were more stimulatory than either alone. These and other combinations that stimulate keratinocyte migration in vitro should be tested for effect on wound closure and repair in vivo. The scratch wound assay provides a useful, inexpensive and easy-to-perform screening method for testing individual or combinations of growth factors or cytokines, or growth factors combined with other modalities such as laser irradiation, prior to performing wound healing studies with laboratory animals. Copyright © 2013 Elsevier Ltd. All rights reserved.

Dual growth factor-immobilized asymmetrically porous membrane for bone-to-tendon interface regeneration on rat patellar tendon avulsion model.

PubMed

Kim, Joong-Hyun; Oh, Se Heang; Min, Hyun Ki; Lee, Jin Ho

2018-01-01

Insufficient repair of the bone-to-tendon interface (BTI) with structural/compositional gradients has been a significant challenge in orthopedics. In this study, dual growth factor (platelet-derived growth factor-BB [PDGF-BB] and bone morphogenetic protein-2 [BMP-2])-immobilized polycaprolactone (PCL)/Pluronic F127 asymmetrically porous membrane was fabricated to estimate its feasibility as a potential strategy for effective regeneration of BTI injury. The growth factors immobilized (via heparin-intermediated interactions) on the membrane were continuously released for up to ∼80% of the initial loading amount after 5 weeks without a significant initial burst. From the in vivo animal study using a rat patellar tendon avulsion model, it was observed that the PDGF-BB/BMP-2-immobilized membrane accelerates the regeneration of the BTI injury, probably because of the continuous release of both growth factors (biological stimuli) and their complementary effect to create a multiphasic structure (bone, fibrocartilage, and tendon) like a native structure, as well as the role of the asymmetrically porous membrane as a physical barrier (nanopore side; prevention of fibrous tissue invasion into the defect site) and scaffold (micropore side; guidance for tissue regeneration). © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 115-125, 2018. © 2017 Wiley Periodicals, Inc.

Insulin-like growth factor 1: common mediator of multiple enterotrophic hormones and growth factors.

PubMed

Bortvedt, Sarah F; Lund, P Kay

2012-03-01

To summarize the recent evidence that insulin-like growth factor 1 (IGF1) mediates growth effects of multiple trophic factors and discuss clinical relevance. Recent reviews and original reports indicate benefits of growth hormone (GH) and long-acting glucagon-like peptide 2 (GLP2) analogs in short bowel syndrome and Crohn's disease. This review highlights the evidence that biomarkers of sustained small intestinal growth or mucosal healing and evaluation of intestinal epithelial stem cell biomarkers may improve clinical measures of intestinal growth or response to trophic hormones. Compelling evidence that IGF1 mediates growth effects of GH and GLP2 on intestine or linear growth in preclinical models of resection or Crohn's disease is presented, along with a concept that these hormones or IGF1 may enhance sustained growth if given early after bowel resection. Evidence that suppressor of cytokine signaling protein induction by GH or GLP2 in normal or inflamed intestine may limit IGF1-induced growth, but protect against risk of dysplasia or fibrosis, is reviewed. Whether IGF1 receptor mediates IGF1 action and potential roles of insulin receptors are addressed. IGF1 has a central role in mediating trophic hormone action in small intestine. Better understanding of benefits and risks of IGF1, receptors that mediate IGF1 action, and factors that limit undesirable growth are needed.

FGF growth factor analogs

DOEpatents

Zamora, Paul O [Gaithersburg, MD; Pena, Louis A [Poquott, NY; Lin, Xinhua [Plainview, NY; Takahashi, Kazuyuki [Germantown, MD

2012-07-24

The present invention provides a fibroblast growth factor heparin-binding analog of the formula: ##STR00001## where R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, X, Y and Z are as defined, pharmaceutical compositions, coating compositions and medical devices including the fibroblast growth factor heparin-binding analog of the foregoing formula, and methods and uses thereof.

Growth factors in porcine full and partial thickness burn repair. Differing targets and effects of keratinocyte growth factor, platelet-derived growth factor-BB, epidermal growth factor, and neu differentiation factor.

PubMed Central

Danilenko, D. M.; Ring, B. D.; Tarpley, J. E.; Morris, B.; Van, G. Y.; Morawiecki, A.; Callahan, W.; Goldenberg, M.; Hershenson, S.; Pierce, G. F.

1995-01-01

The topical application of recombinant growth factors such as epidermal growth factor, platelet-derived growth factor-BB homodimer (rPDGF-BB), keratinocyte growth factor (rKGF), and neu differentiation factor has resulted in significant acceleration of healing in several animal models of wound repair. In this study, we established highly reproducible and quantifiable full and deep partial thickness porcine burn models in which burns were escharectomized 4 or 5 days postburn and covered with an occlusive dressing to replicate the standard treatment in human burn patients. We then applied these growth factors to assess their efficacy on several parameters of wound repair: extracellular matrix and granulation tissue production, percent reepithelialization, and new epithelial area. In full thickness burns, only rPDGF-BB and the combination of rPDGF-BB and rKGF induced significant changes in burn repair. rPDGF-BB induced marked extracellular matrix and granulation tissue production (P = 0.013) such that the burn defect was filled within several days of escharectomy, but had no effect on new epithelial area or reepithelialization. The combination of rPDGF-BB and rKGF in full thickness burns resulted in a highly significant increase in extracellular matrix and granulation tissue area (P = 0.0009) and a significant increase in new epithelial area (P = 0.007), but had no effect on reepithelialization. In deep partial thickness burns, rKGF induced the most consistent changes. Daily application of rKGF induced a highly significant increase in new epithelial area (P < 0.0001) but induced only a modest increase in reepithelialization (83.7% rKGF-treated versus 70.2% control; P = 0.016) 12 days postburn. rKGF also doubled the number of fully reepithelialized burns (P = 0.02) at 13 days postburn, at least partially because of marked stimulation of both epidermal and follicular proliferation as assessed by proliferating cell nuclear antigen expression. In situ hybridization for

Regulation of Transforming Growth Factor β1, Platelet-Derived Growth Factor, and Basic Fibroblast Growth Factor by Silicone Gel Sheeting in Early-Stage Scarring.

PubMed

Choi, Jaehoon; Lee, Eun Hee; Park, Sang Woo; Chang, Hak

2015-01-01

Hypertrophic scars and keloids are associated with abnormal levels of growth factors. Silicone gel sheets are effective in treating and preventing hypertrophic scars and keloids. There has been no report on the change in growth factors in the scar tissue following the use of silicone gel sheeting for scar prevention. A prospective controlled trial was performed to evaluate whether growth factors are altered by the application of a silicone gel sheet on a fresh surgical scar. Four of seven enrolled patients completed the study. Transforming growth factor (TGF)-β1, platelet-derived growth factor (PDGF), and basic fibroblast growth factor (bFGF) were investigated immunohistochemically in biopsies taken from five scars at 4 months following surgery. In both the epidermis and the dermis, the expression of TGF-β1 (P=0.042 and P=0.042) and PDGF (P=0.043 and P=0.042) was significantly lower in the case of silicone gel sheet-treated scars than in the case of untreated scars. The expression of bFGF in the dermis was significantly higher in the case of silicone gel sheet-treated scars than in the case of untreated scars (P=0.042), but in the epidermis, the expression of bFGF showed no significant difference between the groups (P=0.655). The levels of TGF-β1, PDGF, and bFGF are altered by the silicone gel sheet treatment, which might be one of the mechanisms of action in scar prevention.

Growth factors, nutrient signaling, and cardiovascular aging.

PubMed

Fontana, Luigi; Vinciguerra, Manlio; Longo, Valter D

2012-04-13

Growth factors regulated by specific macronutrients have been shown to promote aging and accelerate mortality in the majority of the organisms studied. In particular, the enzymes activated by growth hormone, insulin, and insulin-like growth factor-1 in mammals and their orthologs in simple model organisms represent perhaps the best-understood proteins involved in the aging process. Dietary restriction, which reduces the level of insulin-like growth factor-1 and of other growth factors, has been associated with protection from diabetes, cancer, and cardiovascular diseases, and deficiencies in growth hormone signaling and insulin-like growth factor-1 are strongly associated with protection from cancer and diabetes in both mice and humans; however, their role in cardiac function and cardiovascular diseases is controversial. Here, we review the link between growth factors, cardiac function, and heart disease with focus on the cardioprotective and sensitizing effect of growth factors in both model organisms and humans.

Synthetic design of growth factor sequestering extracellular matrix mimetic hydrogel for promoting in vivo bone formation.

PubMed

Yan, Hong Ji; Casalini, Tommaso; Hulsart-Billström, Gry; Wang, Shujiang; Oommen, Oommen P; Salvalaglio, Matteo; Larsson, Sune; Hilborn, Jöns; Varghese, Oommen P

2018-04-01

Synthetic scaffolds that possess an intrinsic capability to protect and sequester sensitive growth factors is a primary requisite for developing successful tissue engineering strategies. Growth factors such as recombinant human bone morphogenetic protein-2 (rhBMP-2) is highly susceptible to premature degradation and to provide a meaningful clinical outcome require high doses that can cause serious side effects. We discovered a unique strategy to stabilize and sequester rhBMP-2 by enhancing its molecular interactions with hyaluronic acid (HA), an extracellular matrix (ECM) component. We found that by tuning the initial protonation state of carboxylic acid residues of HA in a covalently crosslinked hydrogel modulate BMP-2 release at physiological pH by minimizing the electrostatic repulsion and maximizing the Van der Waals interactions. At neutral pH, BMP-2 release is primarily governed by Fickian diffusion, whereas at acidic pH both diffusion and electrostatic interactions between HA and BMP-2 become important as confirmed by molecular dynamics simulations. Our results were also validated in an in vivo rat ectopic model with rhBMP-2 loaded hydrogels, which demonstrated superior bone formation with acidic hydrogel as compared to the neutral counterpart. We believe this study provides new insight on growth factor stabilization and highlights the therapeutic potential of engineered matrices for rhBMP-2 delivery and may help to curtail the adverse side effects associated with the high dose of the growth factor. Copyright © 2018 Elsevier Ltd. All rights reserved.

Stanniocalcin-2 Inhibits Mammalian Growth by Proteolytic Inhibition of the Insulin-like Growth Factor Axis*

PubMed Central

Jepsen, Malene R.; Kløverpris, Søren; Mikkelsen, Jakob H.; Pedersen, Josefine H.; Füchtbauer, Ernst-Martin; Laursen, Lisbeth S.; Oxvig, Claus

2015-01-01

Mammalian stanniocalcin-2 (STC2) is a secreted polypeptide widely expressed in developing and adult tissues. However, although transgenic expression in mice is known to cause severe dwarfism, and targeted deletion of STC2 causes increased postnatal growth, its precise biological role is still unknown. We found that STC2 potently inhibits the proteolytic activity of the growth-promoting metalloproteinase, pregnancy-associated plasma protein-A (PAPP-A). Proteolytic inhibition requires covalent binding of STC2 to PAPP-A and is mediated by a disulfide bond, which involves Cys-120 of STC2. Binding of STC2 prevents PAPP-A cleavage of insulin-like growth factor-binding protein (IGFBP)-4 and hence release within tissues of bioactive IGF, required for normal growth. Concordantly, we show that STC2 efficiently inhibits PAPP-A-mediated IGF receptor signaling in vitro and that transgenic mice expressing a mutated variant of STC2, STC2(C120A), which is unable to inhibit PAPP-A, grow like wild-type mice. Our work identifies STC2 as a novel proteinase inhibitor and a previously unrecognized extracellular component of the IGF system. PMID:25533459

Peripheral blood "endothelial progenitor cells" are derived from monocyte/macrophages and secrete angiogenic growth factors.

PubMed

Rehman, Jalees; Li, Jingling; Orschell, Christie M; March, Keith L

2003-03-04

Endothelial progenitor cells (EPCs) have been isolated from peripheral blood and can enhance angiogenesis after infusion into host animals. It is not known whether the proangiogenic effects are a result of such events as endothelial differentiation and subsequent proliferation of EPCs or secondary to secretion of angiogenic growth factors. Human EPCs were isolated as previously described, and their phenotypes were confirmed by uptake of acetylated LDL and binding of ulex-lectin. EPC proliferation and surface marker expression were analyzed by flow cytometry, and conditioned medium was assayed for growth factors. The majority of EPCs expressed monocyte/macrophage markers such as CD14 (95.7+/-0.3%), Mac-1 (57.6+/-13.5%), and CD11c (90.8+/-4.9%). A much lower percentage of cells expressed the specific endothelial marker VE-cadherin (5.2+/-0.7%) or stem/progenitor-cell markers AC133 (0.16+/-0.05%) and c-kit (1.3+/-0.7%). Compared with circulating monocytes, cultured EPCs showed upregulation of monocyte activation and macrophage differentiation markers. EPCs did not demonstrate any significant proliferation but did secrete the angiogenic growth factors vascular endothelial growth factor, hepatocyte growth factor, granulocyte colony-stimulating factor, and granulocyte-macrophage colony-stimulating factor. Our findings suggest that acetylated LDL(+)ulex-lectin(+) cells, commonly referred to as EPCs, do not proliferate but release potent proangiogenic growth factors. The majority of acetylated LDL(+)ulex-lectin(+) cells are derived from monocyte/macrophages. The findings of low proliferation and endothelial differentiation suggest that their angiogenic effects are most likely mediated by growth factor secretion. These findings may allow for development of novel angiogenic therapies relying on secreted growth factors or on recruitment of endogenous monocytes/macrophages to sites of ischemia.

Temporal growth factor release from platelet-rich plasma, trehalose lyophilized platelets, and bone marrow aspirate and their effect on tendon and ligament gene expression.

PubMed

McCarrel, Taralyn; Fortier, Lisa

2009-08-01

Platelet-rich plasma (PRP) has generated substantial interest for tendon and ligament regeneration because of the high concentrations of growth factors in platelet alpha-granules. This study compared the temporal release of growth factors from bone marrow aspirate (BMA), PRP, and lyophilized platelet product (PP), and measured their effects on tendon and ligament gene expression. Blood and BMA were collected and processed to yield PRP and plasma. Flexor digitorum superficialis tendon (FDS) and suspensory ligament (SL) explants were cultured in 10% plasma in DMEM (control), BMA, PRP, or PP. TGF-beta1 and PDGF-BB concentrations were determined at 0, 24, and 96 h of culture using ELISA. Quantitative RT-PCR for collagen types I and III (COL1A1, COL3A1), cartilage oligomeric matrix protein (COMP), decorin, and matrix metalloproteinases-3 and 13 (MMP-3, MMP-13) was performed. TGF-beta1 and PDGF-BB concentrations were highest in PRP and PP. Growth factor quantity was unchanged in BMA, increased in PRP, and decreased in PP over 4 days. TGF-beta1 and platelet concentrations were positively correlated. Lyophilized PP and PRP resulted in increased COL1A1:COL3A1 ratio, increased COMP, and decreased MMP-13 expression. BMA resulted in decreased COMP and increased MMP-3 and MMP-13 gene expression. Platelet concentration was positively correlated with COL1A1, ratio of COL1A1:COL3A1, and COMP, and negatively correlated with COL3A1, MMP-13, and MMP-3. White blood cell concentration was positively correlated with COL3A1, MMP3, and MMP13, and negatively correlated with a ratio of COL1A1:COL3A1, COMP, and decorin. These findings support further in vivo investigation of PRP and PP for treatment of tendonitis and desmitis. Copyright 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

A novel sustained-release formulation of recombinant human growth hormone and its pharmacokinetic, pharmacodynamic and safety profiles.

PubMed

Wei, Yi; Wang, Yuxia; Kang, Aijun; Wang, Wei; Ho, Sa V; Gao, Junfeng; Ma, Guanghui; Su, Zhiguo

2012-07-02

An effective and safe formulation of sustained-release rhGH for two months using poly(monomethoxypolyethylene glycol-co-D,L-lactide) (mPEG-PLA, PELA) microspheres was developed to reduce the frequency of medication. The rhGH-loaded PELA microspheres with a narrow size distribution were successfully prepared by a double emulsion method combined with a premix membrane emulsification technique without any exogenous stabilizing excipients. The narrow size distribution of the microspheres would guarantee repeatable productivity and release behavior. Moreover, the amphiphilic PELA improved the bioactivity retention of protein drugs since it prevented protein contact with the oil/water interface and the hydrophobic network, and modulated diffusion of acidic degradation products from the carrier system. These PELA microspheres were compared in vivo with commercial rhGH solution, conventional poly(D,L-lactic acid) (PLA) and poly(D,L-lactic-co-glycolic acid) (PLGA) microspheres. Administration of rhGH-PELA could extend the duration of rhGH release (for up to 56 days) and increase area under the curve (AUC) compared to rhGH solution, PLA or PLGA microspheres in Sprague-Dawley (SD) rats. In addition, rhGH-PELA microspheres induced a greater response in total insulin-like growth factor-1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) than other rhGH formulations. With a hypophysectomized SD rat model, the pharmacological efficacy of rhGH-PELA microspheres was shown to be better than that from daily administration of rhGH solutions over 6 days based on body weight gain and width of the tibial growth plate. Histological examination of the injection sites indicated a significantly milder inflammatory response than that observed after injection of PLA and PLGA microspheres. Neither anti-rhGH antibodies nor the toxic effects on heart, liver and kidney were detectable after administration of rhGH-PELA microspheres in SD rats. These results suggest that rh

Growth/differentiation factor-11: an evolutionary conserved growth factor in vertebrates.

PubMed

Funkenstein, Bruria; Olekh, Elena

2010-11-01

Growth and differentiation factor-11 (GDF-11) is a member of the transforming growth factor-β superfamily and is thought to be derived together with myostatin (known also as GDF-8) from an ancestral gene. In the present study, we report the isolation and characterization of GDF-11 homolog from a marine teleost, the gilthead sea bream Sparus aurata, and show that this growth factor is highly conserved throughout vertebrates. Using bioinformatics, we identified GDF-11 in Tetraodon, Takifugu, medaka, and stickleback and found that they are highly conserved at the amino acid sequence as well as gene organization. Moreover, we found conservation of syntenic relationships among vertebrates in the GDF-11 locus. Transcripts for GDF-11 can be found in eggs and early embryos, albeit at low levels, while in post-hatching larvae expression levels are high and decreases as development progresses, suggesting that GDF-11 might have a role during early development of fish as found in tetrapods and zebrafish. Finally, GDF-11 is expressed in various tissues in the adult fish including muscle, brain, and eye.

Effect of catch-and-release angling on growth and survival of rainbow trout, Oncorhynchus mykiss

USGS Publications Warehouse

Pope, K.L.; Wilde, G.R.; Knabe, D.W.

2007-01-01

Catch-and-release angling is popular in many parts of the world and plays an increasingly important role in fish conservation efforts. Although survival rates associated with catch-and-release angling are well documented for many species, sublethal effects have been less studied. An experiment was conducted to directly assess the effects of catch-and-release angling on growth and survival of rainbow trout, Oncorhynchus mykiss (Walbaum). Catch-and-release events were simulated in laboratory tanks maintained at 15-16 ??C with hooks manually placed in pre-designated locations in the mouths of the fish. There were no differences in standard length (P = 0.59) or wet weight (P = 0.81) gained between caught and uncaught fish over a 1-month angling and recovery period. Survival was 96.99 ?? 0.06% for rainbow trout caught and released, and did not vary with number (one, two or four) of captures. Thus, catch-and-release angling appears to have little effect on growth and mortality of rainbow trout hooked in the mouth. ?? 2007 The Authors. Journal compilation 2007 Blackwell Publishing Ltd.

PLACENTAL GROWTH FACTOR ADMINISTRATION ABOLISHES PLACENTAL ISCHEMIA-INDUCED HYPERTENSION

PubMed Central

Spradley, Frank T.; Tan, Adelene Y.; Joo, Woo S.; Daniels, Garrett; Kussie, Paul; Karumanchi, S. Ananth; Granger, Joey P.

2016-01-01

Preeclampsia is a pregnancy-specific disorder of new-onset hypertension. Unfortunately, the most effective treatment is early delivery of the fetus and placenta. Placental ischemia appears central to the pathogenesis of preeclampsia as placental ischemia/hypoxia induced in animals by reduced uterine perfusion pressure (RUPP) or in humans stimulates release of hypertensive placental factors into the maternal circulation. The anti-angiogenic factor soluble fms-like tyrosine kinase-1 (sFlt-1), which antagonizes and reduces bioavailable vascular endothelial growth factor (VEGF) and placental growth factor (PlGF), is elevated in RUPP rats and preeclampsia. Although PlGF and VEGF are both natural ligands for sFlt-1, VEGF also has high affinity to VEGFR2 (Flk-1) causing side effects like edema. PlGF is specific for sFlt-1. We tested the hypothesis that PlGF treatment reduces placental ischemia-induced hypertension by antagonizing sFlt-1 without adverse consequences to the mother or fetus. On gestational day 14, rats were randomized to four groups: normal pregnant (NP) or RUPP ± infusion of rhPlGF (180 μg/kg/day; AG31, a purified, recombinant human form of PlGF) for 5 days via intraperitoneal osmotic minipumps. On day 19, mean arterial blood pressure and plasma sFlt-1 were higher and glomerular filtration rate lower in RUPP than NP rats. Infusion of rhPlGF abolished these changes seen with RUPP along with reducing oxidative stress. These data indicate that the increased sFlt-1 and reduced PlGF resulting from placental ischemia contribute to maternal hypertension. Our novel finding that rhPlGF abolishes placental ischemia-induced hypertension, without major adverse consequences, suggests a strong therapeutic potential for this growth factor in preeclampsia. PMID:26831193

Delivering growth factors through a polymeric scaffold to cell cultures containing both nucleus pulposus and annulus fibrosus.

PubMed

Akyuva, Yener; Kaplan, Necati; Yilmaz, Ibrahim; Ozbek, Hanefi; Sirin, Duygu Yasar; Karaaslan, Numan; Guler, Olcay; Ateş, Özkan

2018-04-09

The aim of this in vitro experimental study was to design a novel, polyvinyl alcohol(PVA)-basedpolymericscaffold that permits the controlled release of insulin-likegrowthfactor1(IGF-1)/bonemorphogenetic protein-2(BMP-2) following intervertebral disc administration. The drug delivery system was composed of two different solutions that formed a scaffold within seconds after coming into contact with each other. We performed swelling,pH,temperature tests and analysis of the controlled release of growth factors from this system.The release kinetics of the growth factors was determined through enzyme linked immunosorbent assay(ELISA). Cell proliferation and viability was monitored with microscopy and analyzed using an MTT assay and acridine orange/propidium iodide(AO/PI) staining. Chondroadherin(CHAD), hypoxiainduciblefactor-1alpha(HIF-1α),collagentypeII(COL2A1) gene expressions were determined with quantitative real-timepolymerasechainreaction(qRT-PCR) analysis to show the effects of IGF-1/BMP-2 administration on annulus fibrosus cell(AFC)/nucleus pulposus cell(NPC) cultures. The scaffold allowed for the controlled release of IGF-1 and BMP-2 in different time intervals. It was observed that as the application time increased, the number of cells and the degree of extracellular matrix development increased in AFC/NPC cultures. AO/PI staining and an MTT analysis showed that cells retained their specific morphology and continued to proliferate. It was observed that HIF-1α and CHAD expression increased in a time-dependent manner, and there wasn't any COL2A1 expression in the AFC/NPC cultures. The designed scaffold may be used as an alternative method for intervertebral disc administration of growth factors after further in vivo studies. We believe that such prototype scaffolds may be an innovative technology in targeted drug therapies after reconstructive neurosurgeries.

Insulin-Like Growth Factor and Epidermal Growth Factor Signaling in Breast Cancer Cell Growth: Focus on Endocrine Resistant Disease

PubMed Central

Berdiaki, Aikaterini; Tzardi, Maria

2015-01-01

Breast cancer is the most common type of cancer for women worldwide with a lifetime risk amounting to a staggering total of 10%. It is well established that the endogenous synthesis of insulin-like growth factor (IGF) and epidermal growth factor (EGF) polypeptide growth factors are closely correlated to malignant transformation and all the steps of the breast cancer metastatic cascade. Numerous studies have demonstrated that both estrogens and growth factors stimulate the proliferation of steroid-dependent tumor cells, and that the interaction between these signaling pathways occurs at several levels. Importantly, the majority of breast cancer cases are estrogen receptor- (ER-) positive which have a more favorable prognosis and pattern of recurrence with endocrine therapy being the backbone of treatment. Unfortunately, the majority of patients progress to endocrine therapy resistant disease (acquired resistance) whereas a proportion of patients may fail to respond to initial therapy (de novo resistance). The IGF-I and EGF downstream signaling pathways are closely involved in the process of progression to therapy resistant disease. Modifications in the bioavailability of these growth factors contribute critically to disease progression. In the present review therefore, we will discuss in depth how IGF and EGF signaling participate in breast cancer pathogenesis and progression to endocrine resistant disease. PMID:26258011

Evaluation of growth hormone release and human growth hormone treatment in children with cranial irradiation-associated short stature

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

Romshe, C.A.; Zipf, W.B.; Miser, A.

1984-02-01

We studied nine children who had received cranial irradiation for various malignancies and subsequently experienced decreased growth velocity. Their response to standard growth hormone stimulation and release tests were compared with that in seven children with classic GH deficiency and in 24 short normal control subjects. With arginine and L-dopa stimulation, six of nine patients who received radiation had a normal GH response (greater than 7 ng/ml), whereas by design none of the GH deficient and all of the normal children had a positive response. Only two of nine patients had a normal response to insulin hypoglycemia, with no significantmore » differences in the mean maximal response of the radiation and the GH-deficient groups. Pulsatile secretion was not significantly different in the radiation and GH-deficient groups, but was different in the radiation and normal groups. All subjects in the GH-deficient and radiation groups were given human growth hormone for 1 year. Growth velocity increased in all, with no significant difference in the response of the two groups when comparing the z scores for growth velocity of each subject's bone age. We recommend a 6-month trial of hGH in children who have had cranial radiation and are in prolonged remission with a decreased growth velocity, as there is no completely reliable combination of GH stimulation or release tests to determine their response.« less

Insulin-like growth factor I (IGF-1) Ec/Mechano Growth factor--a splice variant of IGF-1 within the growth plate.

PubMed

Schlegel, Werner; Raimann, Adalbert; Halbauer, Daniel; Scharmer, Daniela; Sagmeister, Susanne; Wessner, Barbara; Helmreich, Magdalena; Haeusler, Gabriele; Egerbacher, Monika

2013-01-01

Human insulin-like growth factor 1 Ec (IGF-1Ec), also called mechano growth factor (MGF), is a splice variant of insulin-like growth factor 1 (IGF-1), which has been shown in vitro as well as in vivo to induce growth and hypertrophy in mechanically stimulated or damaged muscle. Growth, hypertrophy and responses to mechanical stimulation are important reactions of cartilaginous tissues, especially those in growth plates. Therefore, we wanted to ascertain if MGF is expressed in growth plate cartilage and if it influences proliferation of chondrocytes, as it does in musculoskeletal tissues. MGF expression was analyzed in growth plate and control tissue samples from piglets aged 3 to 6 weeks. Furthermore, growth plate chondrocyte cell culture was used to evaluate the effects of the MGF peptide on proliferation. We showed that MGF is expressed in considerable amounts in the tissues evaluated. We found the MGF peptide to be primarily located in the cytoplasm, and in some instances, it was also found in the nucleus of the cells. Addition of MGF peptides was not associated with growth plate chondrocyte proliferation.

Cytotoxic T lymphocyte-dependent tumor growth inhibition by a vascular endothelial growth factor-superantigen conjugate

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

Sun, Qingwen; State Key Laboratory of Genetic Engineering, Fudan University, Shanghai 200433; Jiang, Songmin

2012-11-02

Highlights: Black-Right-Pointing-Pointer We construct and purify a fusion protein VEGF-SEA. Black-Right-Pointing-Pointer VEGF-SEA strongly repressed the growth of murine solid sarcoma 180 (S180) tumors. Black-Right-Pointing-Pointer T cells driven by VEGF-SEA were accumulated around tumor cells bearing VEGFR by mice image model. Black-Right-Pointing-Pointer VEGF-SEA can serve as a tumor targeting agent and sequester CTLs into the tumor site. Black-Right-Pointing-Pointer The induced CTLs could release the cytokines, perforins and granzyme B to kill the tumor cells. -- Abstract: T cells are major lymphocytes in the blood and passengers across the tumor vasculature. If these T cells are retained in the tumor site, amore » therapeutic potential will be gained by turning them into tumor-reactive cytotoxic T lymphocytes (CTLs). A fusion protein composed of human vascular endothelial growth factor (VEGF) and staphylococcal enterotoxin A (SEA) with a D227A mutation strongly repressed the growth of murine solid sarcoma 180 (S180) tumors (control versus VEGF-SEA treated with 15 {mu}g, mean tumor weight: 1.128 g versus 0.252 g, difference = 0.876 g). CD4{sup +} and CD8{sup +} T cells driven by VEGF-SEA were accumulated around VEGFR expressing tumor cells and the induced CTLs could release the tumoricidal cytokines, such as interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha). Meanwhile, intratumoral CTLs secreted cytolytic pore-forming perforin and granzyme B proteins around tumor cells, leading to the death of tumor cells. The labeled fusion proteins were gradually targeted to the tumor site in an imaging mice model. These results show that VEGF-SEA can serve as a tumor targeting agent and sequester active infiltrating CTLs into the tumor site to kill tumor cells, and could therefore be a potential therapeutical drug for a variety of cancers.« less

The Effect of Desulfation of Chondroitin Sulfate on Interactions with Positively Charged Growth Factors and Upregulation of Cartilaginous Markers in Encapsulated MSCs

PubMed Central

Lim, Jeremy J.; Temenoff, Johnna S.

2013-01-01

Sulfated glycosaminoglycans (GAGs) are known to interact electrostatically with positively charged growth factors to modulate signaling. Therefore, regulating the degree of sulfation of GAGs may be a promising approach to tailor biomaterial carriers for controlled growth factor delivery and release. For this study, chondroitin sulfate (CS) was first desulfated to form chondroitin, and resulting crosslinked CS and chondroitin hydrogels were examined in vitro for release of positively charged model protein (histone) and for their effect on cartilaginous differentiation of encapsulated human mesenchymal stem cells (MSCs). Desulfation significantly increased the release of histone from chondroitin hydrogels (30.6±2.3 ìg released over 8 days, compared to natively sulfated CS with 20.2±0.8 ìg), suggesting that sulfation alone plays a significant role in modulating protein interactions with GAG hydrogels. MSCs in chondroitin hydrogels significantly upregulated gene expression of collagen II and aggrecan by day 21 in chondrogenic medium (115±100 and 23.1±7.9 fold upregulation of collagen II and aggrecan, respectively), compared to CS and PEG-based swelling controls, indicating that desulfation may actually enhance the response of MSCs to soluble chondrogenic cues, such as TGF-â1. Thus, desulfated chondroitin materials present a promising biomaterial tool to further investigate electrostatic GAG/growth factor interactions, especially for repair of cartilaginous tissues. PMID:23570717

The effect of desulfation of chondroitin sulfate on interactions with positively charged growth factors and upregulation of cartilaginous markers in encapsulated MSCs.

PubMed

Lim, Jeremy J; Temenoff, Johnna S

2013-07-01

Sulfated glycosaminoglycans (GAGs) are known to interact electrostatically with positively charged growth factors to modulate signaling. Therefore, regulating the degree of sulfation of GAGs may be a promising approach to tailor biomaterial carriers for controlled growth factor delivery and release. For this study, chondroitin sulfate (CS) was first desulfated to form chondroitin, and resulting crosslinked CS and chondroitin hydrogels were examined in vitro for release of positively charged model protein (histone) and for their effect on cartilaginous differentiation of encapsulated human mesenchymal stem cells (MSCs). Desulfation significantly increased the release of histone from chondroitin hydrogels (30.6 ± 2.3 μg released over 8 days, compared to natively sulfated CS with 20.2 ± 0.8 μg), suggesting that sulfation alone plays a significant role in modulating protein interactions with GAG hydrogels. MSCs in chondroitin hydrogels significantly upregulated gene expression of collagen II and aggrecan by day 21 in chondrogenic medium (115 ± 100 and 23.1 ± 7.9 fold upregulation of collagen II and aggrecan, respectively), compared to CS hydrogels and PEG-based swelling controls, indicating that desulfation may actually enhance the response of MSCs to soluble chondrogenic cues, such as TGF-β1. Thus, desulfated chondroitin materials present a promising biomaterial tool to further investigate electrostatic GAG/growth factor interactions, especially for repair of cartilaginous tissues. Copyright © 2013 Elsevier Ltd. All rights reserved.

Endocrinological control of growth.

PubMed

Sizonenko, P C

1978-01-01

Many endocrinological factors control cellular growth of different tissues (cell multiplication and cell volume) and skeletal growth. The role of neuro-transmitters and of hypothalamic releasing and inhibiting factors of growth hormone secretion will be reviewed. The importance of the somatomedins on cartilage growth will be stressed. Thyroid hormones, androgens, and oestrogens have important stimulating actions on skeletal growth and maturation. Conversely, glucocorticoids have an important inhibitory effect on growth. The precise roles of these hormone factors in the regulation of growth hormone secretion, somatomedin production and tissue growth, particularly the cartilage, remain to be completely elucidated.

Growth factors for nanobacteria

NASA Astrophysics Data System (ADS)

Ciftcioglu, Neva; Kajander, E. Olavi

1999-12-01

Nanobacteria are novel microorganisms recently isolated from fetal bovine serum and blood of cows and humans. These coccoid, gram negative bacteria in alpha-2 subgroup of Proteobacteria grow slowly under mammalian cell culture conditions but not in common media for microbes. Now we have found two different kinds of culture supplement preparations that improve their growth and make them culturable in the classical sense. These are supernatant fractions of conditioned media obtained from 1 - 3 months old nanobacteria cultures and from about a 2 weeks old Bacillus species culture. Both improved multiplication and particle yields and the latter increased their resistance to gentamicin. Nanobacteria cultured with any of the methods shared similar immunological property, structure and protein pattern. The growth supporting factors were heat-stabile and nondialyzable, and dialysis improved the growth promoting action. Nanobacteria formed stony colonies in a bacteriological medium supplemented with the growth factors. This is an implication that nanobacterial growth is influenced by pre-existing bacterial flora.

Effects of release procedures on the primary stress response and post-release survival and growth of hatchery-reared spotted seatrout Cynoscion nebulosus.

PubMed

Guest, T W; Rakocinski, C F; Evans, A N; Blaylock, R B

2017-03-01

To help explain the apparent poor post-release success of hatchery-reared (HR) spotted seatrout Cynoscion nebulosus, this study examined the effects of handling, transport and release procedures on the stress response of two age classes [48 and 80 day post-hatch (dph)] of HR C. nebulosus, as measured by cortisol concentrations and the post-release survival and growth of 48 and 80 dph HR C. nebulosus. As a proxy for stress, tissue cortisol was measured at various times during the handling, tagging (80 dph), transport, acclimation and release process. To consider the implications of the pre-release stressors, growth and survival were monitored in separate field experiments for each age class of acclimated post-transport C. nebulosus using control C. nebulosus that only experienced anaesthesia, transport, acclimation and a net release v. experimental C. nebulosus that underwent the entire routine procedure, including anaesthesia, tagging, transport, acclimation and gravity release through a pipe. For 48 dph C. nebulosus, mean cortisol varied significantly throughout handling and transport, increasing more than six-fold from controls before decreasing in mean concentration just prior to release. For 80 dph C. nebulosus, cortisol varied throughout handling, tagging and transport, first increasing more than three-fold compared with control C. nebulosus, before decreasing and rising slightly just prior to release. For 48 dph C. nebulosus within field enclosures, survival was high and similar for control and experimental groups; experimental C. nebulosus, however, were shorter, lighter and lower in condition than control C. nebulosus. For 80 dph C. nebulosus within field enclosures, fewer experimental C. nebulosus survived and those that did survive were of lower condition than C. nebulosus from the control group. Small untagged C. nebulosus may survive the release procedure better than larger C. nebulosus carrying a coded-wire tag. These findings document

Research on growth factors in periodontology.

PubMed

Smith, Patricio C; Martínez, Constanza; Cáceres, Mónica; Martínez, Jorge

2015-02-01

Growth factors play critical roles in periodontal repair through the regulation of cell behavior. Many of the cell responses regulated by these proteins include cell adhesion, migration, proliferation and differentiation. Periodontal regeneration involves an organized response of different cells, tissues and growth factors implicated in the coordination of these events. However, periodontal tissue reconstruction is an extremely difficult task. Multiple studies have been performed to understand the specific role of growth factors in periodontal wound healing. In the present review we analyze the evidence that supports the roles of growth factors in periodontal wound healing and regeneration. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Prolonged controlled delivery of nerve growth factor using porous silicon nanostructures.

PubMed

Zilony, Neta; Rosenberg, Michal; Holtzman, Liran; Schori, Hadas; Shefi, Orit; Segal, Ester

2017-07-10

Although nerve growth factor (NGF) is beneficial for the treatment of numerous neurological and non-neurological diseases, its therapeutic administration represents a significant challenge, due to the difficulty to locally deliver relevant doses in a safe and non-invasive manner. In this work, we employ degradable nanostructured porous silicon (PSi) films as carriers for NGF, allowing its continuous and prolonged release, while retaining its bioactivity. The PSi carriers exhibit high loading efficacy (up to 90%) of NGF and a continuous release, with no burst, over a period of>26days. The released NGF bioactivity is compared to that of free NGF in both PC12 cells and dissociated dorsal root ganglion (DRG) neurons. We show that the NGF has retained its bioactivity and induces neurite outgrowth and profound differentiation (of >50% for PC12 cells) throughout the period of release within a single administration. Thus, this proof-of-concept study demonstrates the immense therapeutic potential of these tunable carriers as long-term implants of NGF reservoirs and paves the way for new localized treatment strategies of neurodegenerative diseases. Copyright © 2016 Elsevier B.V. All rights reserved.

Synthetic heparin-binding growth factor analogs

DOEpatents

Pena, Louis A.; Zamora, Paul; Lin, Xinhua; Glass, John D.

2007-01-23

The invention provides synthetic heparin-binding growth factor analogs having at least one peptide chain that binds a heparin-binding growth factor receptor, covalently bound to a hydrophobic linker, which is in turn covalently bound to a non-signaling peptide that includes a heparin-binding domain. The synthetic heparin-binding growth factor analogs are useful as soluble biologics or as surface coatings for medical devices.

Fibroblast growth factor regulates insulin-like growth factor-binding protein production by vascular smooth muscle cells.

PubMed

Ververis, J; Ku, L; Delafontaine, P

1994-02-01

Insulin-like growth factor I is an important mitogen for vascular smooth muscle cells, and its effects are regulated by several binding proteins. Western ligand blotting of conditioned medium from rat aortic smooth muscle cells detected a 24 kDa binding protein and a 28 kDa glycosylated variant of this protein, consistent with insulin-like growth factor binding protein-4 by size. Low amounts of a glycosylated 38 to 42 kDa doublet (consistent with binding protein-3) and a 31 kDa non-glycosylated protein also were present. Basic fibroblast growth factor markedly increased secretion of the 24 kDa binding protein and its 28 kDa glycosylated variant. This effect was dose- and time-dependent and was inhibited by co-incubation with cycloheximide. Crosslinking of [125I]-insulin-like growth factor I to cell monolayers revealed no surface-associated binding proteins, either basally or after agonist treatment. Induction of binding protein production by fibroblast growth factor at sites of vascular injury may be important in vascular proliferative responses in vivo.

Biomimetic Delivery of Keratinocyte Growth Factor upon Cellular Demand for Accelerated Wound Healing in Vitro and in Vivo

PubMed Central

Geer, David J.; Swartz, Daniel D.; Andreadis, Stelios T.

2005-01-01

Exogenous keratinocyte growth factor (KGF) significantly enhances wound healing, but its use is hampered by a short biological half-life and lack of tissue selectivity. We used a biomimetic approach to achieve cell-controlled delivery of KGF by covalently attaching a fluorescent matrix-binding peptide that contained two domains: one recognized by factor XIII and the other by plasmin. Modified KGF was incorporated into the fibrin matrix at high concentration in a factor XIII-dependent manner. Cell-mediated activation of plasminogen to plasmin degraded the fibrin matrix and cleaved the peptides, releasing active KGF to the local microenvironment and enhancing epithelial cell proliferation and migration. To demonstrate in vivo effectiveness, we used a hybrid model of wound healing that involved transplanting human bioengineered skin onto athymic mice. At 6 weeks after grafting, the transplanted tissues underwent full thickness wounding and treatment with fibrin gels containing bound KGF. In contrast to topical KGF, fibrin-bound KGF persisted in the wounds for several days and was released gradually, resulting in significantly enhanced wound closure. A fibrinolytic inhibitor prevented this healing, indicating the requirement for cell-mediated fibrin degradation to release KGF. In conclusion, this biomimetic approach of localized, cell-controlled delivery of growth factors may accelerate healing of large full-thickness wounds and chronic wounds that are notoriously difficult to heal. PMID:16314471

Novel therapeutic approach for pulmonary emphysema using gelatin microspheres releasing basic fibroblast growth factor in a canine model.

PubMed

Chang, Sung Soo; Yokomise, Hiroyasu; Matsuura, Natsumi; Gotoh, Masashi; Tabata, Yasuhiko

2014-08-01

The prognosis of patients with emphysema is poor as there is no truly effective treatment. Our previous study showed that the alveolar space was smaller and the microvessel density was higher in a canine emphysema model after the intrapulmonary arterial administration of gelatin microspheres slowly releasing basic fibroblast growth factor (bFGF-GMS). In the present study, we evaluated the functional effect of injecting bFGF-GMS via the pulmonary artery in this canine pulmonary emphysema model. Using the porcine pancreatic elastase (PPE)-induced total emphysema model, we approximated the value of lung compliance with a Power Lab System, and performed blood gas analysis in a control group, a total emphysema group, and a bFGF group in which bFGF-GMS were injected toward the whole pulmonary artery via the femoral vein. Each group comprised five dogs. Lung compliance was higher in the total emphysema group than in the control group (p = 0.031), and the bFGF group showed no significant improvement of lung compliance vs. the total emphysema group (p = 0.112). PaO2 (partial pressure of oxygen in arterial blood) was improved by administering bFGF-GMS in the total emphysema model (p = 0.027). In the canine total emphysema model, blood gas parameters were improved by the whole pulmonary arterial administration of bFGF-GMS. This method has the potential to be an effective novel therapy for pulmonary emphysema.

Effects of Epidermal Growth Factor-Loaded Mucoadhesive Films on Wounded Oral Tissue Rafts

PubMed Central

Ramineni, Sandeep K.; Fowler, Craig B.; Fisher, Paul D.; Cunningham, Larry L.; Puleo, David A.

2015-01-01

Current treatments for traumatic oral mucosal wounds include the gold standard of autologous tissue and alternative tissue engineered grafts. While use of autografts has disadvantages of minimal availability of oral keratinized tissue, second surgery, and donor site discomfort, tissue engineered grafts are limited by their unavailability as off-the-shelf products owing to their fabrication time of 4–8 weeks. Hence, the current work aimed to develop a potentially cost-effective, readily available device capable of enhancing native mucosal regeneration. Considering the key role of epidermal growth factor (EGF) in promoting mucosal wound regeneration and the advantages of mucoadhesive delivery systems, mucoadhesive films composed of polyvinylpyrrolidone and carboxymethylcellulose were developed to provide sustained release of EGF for minimum of 6 hours. Bioactivity of released EGF supernatants was then confirmed by its ability to promote proliferation of BALB/3T3 fibroblasts. Efficacy of the developed system was then investigated in vitro using buccal tissues (ORL 300-FT) as a potential replacement for small animal studies. Although the mucoadhesive films achieved their desired role of delivering bioactive EGF in a sustained manner, treatment with EGF, irrespective of its release from the films or solubilized in medium, caused a hyperparakeratotic response from in vitro tissues with distinguishable histological features including thickening of the spinous layer, intra- and intercellular edema, and pyknotic nuclei. These significant morphological changes were associated with no improvements in wound closure. These observations raise questions about the potential of using in vitro tissues as a wound healing model and substitute for small animal studies. The mucoadhesive delivery system developed, however, with its potential for sustained release of bioactive growth factors and small molecules, may be loaded with other desired compounds, with or without EGF, to

The Influence of Platelet-Derived Growth Factor and Fibroblast Growth Factor 2 on Oligodendrocyte Development and Remyelination

DTIC Science & Technology

2004-01-01

OLIGODENDROCYTE DEVELOPMENT AND REMYELINATION 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e...Z39-18 ABSTRACT Title: THE INFLUENCE OF PLATELET-DERIVED GROWTH FACTOR AND FIBROBLAST GROWTH FACTOR 2 ON OLIGODENDROCYTE DEVELOPMENT AND...GROWTH FACTOR 2 ON OLIGODENDROCYTE DEVELOPMENT AND REMYELINATION by Joshua C. Murtie Thesis/dissertation submitted to the

The effects of different preservation processes on the total protein and growth factor content in a new biological product developed from human amniotic membrane.

PubMed

Russo, Alessandra; Bonci, Paola; Bonci, Paolo

2012-06-01

The aim of this work is to quantify the total protein and growth factors content in a tissue-suspension obtained from processed human amniotic membrane (hAM). hAM was collected, frozen, freeze dried, powdered and sterilized by γ-irradiation. At each step of the process, samples were characterized for the total protein amounts by a Bradford protein assay and for the growth factor concentrations by ELISA test of the tissue suspensions. Frozen-hAM samples show higher release of total proteins and specific growth factors in the tissue suspension in comparison with freeze-dried hAM. We observed that even if the protein extraction is hindered once the tissue is dried, the powdering process allows a greater release in the tissue suspension of total proteins and growth factors after tissue re-solubilization in comparison with only the freeze-drying process (+91 ± 13% for EGF, +16 ± 4% for HGF, +11 ± 5% for FGF, +16 ± 9% for TGF-β1), and a greater release of EGF (85 ± 10%) in comparison with only the freezing process, because proteins become much readily solubilized in the solution. According with these results, we describe a protocol to obtain a new sterile biological product from hAM tissue, with well-known effects of thermal, mechanical and physical processes on the total protein and grow factors contents.

Insulin-Like Growth Factor I (IGF-1) Ec/Mechano Growth Factor – A Splice Variant of IGF-1 within the Growth Plate

PubMed Central

Schlegel, Werner; Raimann, Adalbert; Halbauer, Daniel; Scharmer, Daniela; Sagmeister, Susanne; Wessner, Barbara; Helmreich, Magdalena; Haeusler, Gabriele; Egerbacher, Monika

2013-01-01

Human insulin-like growth factor 1 Ec (IGF-1Ec), also called mechano growth factor (MGF), is a splice variant of insulin-like growth factor 1 (IGF-1), which has been shown in vitro as well as in vivo to induce growth and hypertrophy in mechanically stimulated or damaged muscle. Growth, hypertrophy and responses to mechanical stimulation are important reactions of cartilaginous tissues, especially those in growth plates. Therefore, we wanted to ascertain if MGF is expressed in growth plate cartilage and if it influences proliferation of chondrocytes, as it does in musculoskeletal tissues. MGF expression was analyzed in growth plate and control tissue samples from piglets aged 3 to 6 weeks. Furthermore, growth plate chondrocyte cell culture was used to evaluate the effects of the MGF peptide on proliferation. We showed that MGF is expressed in considerable amounts in the tissues evaluated. We found the MGF peptide to be primarily located in the cytoplasm, and in some instances, it was also found in the nucleus of the cells. Addition of MGF peptides was not associated with growth plate chondrocyte proliferation. PMID:24146828

Improved vascularization of planar membrane diffusion devices following continuous infusion of vascular endothelial growth factor.

PubMed

Trivedi, N; Steil, G M; Colton, C K; Bonner-Weir, S; Weir, G C

2000-01-01

Improving blood vessel formation around an immunobarrier device should improve the survival of the encapsulated tissue. In the present study we investigated the formation of new blood vessels around a planar membrane diffusion device (the Baxter Theracyte System) undergoing a continuous infusion of vascular endothelial growth factor through the membranes and into the surrounding tissue. Each device (20 microl) had both an inner immunoisolation membrane and an outer vascularizing membrane. Human recombinant vascular endothelial growth factor-165 was infused at 100 ng/day (low dose: n = 6) and 500 ng/day (high dose: n = 7) for 10 days into devices implanted s.c. in Sprague-Dawley rats; noninfused devices transplanted for an identical period were used as controls (n = 5). Two days following the termination of VEGF infusion, devices were loaded with 20 microl of Lispro insulin (1 U/kg) and the kinetics of insulin release from the lumen of the device was assessed. Devices were then explanted and the number of blood vessels (capillary and noncapillary) was quantified using morphometry. High-dose vascular endothelial growth factor infusion resulted in two- to threefold more blood vessels around the device than that obtained with the noninfused devices and devices infused with low-dose vascular endothelial growth factor. This increase in the number of blood vessels was accompanied by a modest increase in insulin diffusion from the device in the high-dose vascular endothelial growth factor infusion group. We conclude that vascular endothelial growth factor can be used to improve blood vessel formation adjacent to planar membrane diffusion devices.

Influence of factors on release of antimicrobials from antimicrobial packaging materials.

PubMed

Wu, Yu-Mei; Wang, Zhi-Wei; Hu, Chang-Ying; Nerín, Cristina

2018-05-03

Antimicrobial packaging materials (films or coatings) (APMs) have aroused great interest among the scientists or the experts specialized in material science, food science, packaging engineering, biology and chemistry. APMs have been used to package the food, such as dairy products, poultry, meat (e.g., beef), salmon muscle, pastry dough, fresh pasta, bakery products, fruits, vegetables and beverages. Some materials have been already commercialized. The ability of APMs to extend the shelf-life of the food depends on the release rate of the antimicrobials (AMs) from the materials to the food. The optimum rate is defined as target release rate (TRR). To achieve TRR, the influencing factors of the release rate should be considered. Herein we reviewed for the first time these factors and their influence on the release. These factors mainly include the AMs, food (or food simulant), packaging materials, the interactions among them, the temperature and environmental relative humidity (RH).

Puberty, statural growth, and growth hormone release in children with cerebral palsy

PubMed Central

Kuperminc, Michelle N.; Gurka, Matthew J.; Houlihan, Christine M.; Henderson, Richard C.; Roemmich, James N.; Rogol, Alan D.

2010-01-01

Objective Children with cerebral palsy (CP) are smaller than normally growing children.. The association between the growth hormone (GH) axis and growth in children with CP during puberty is unknown. We compared growth and markers of the GH axis in pre-pubertal and pubertal children with moderate to severe CP and without CP over a three-year period. Study design Twenty children with CP, ages 6–18, Gross Motor Function Classification System levels III–V, were compared to a group of sixty-three normally growing children of similar age. Anthropometry, Tanner stage, bone age, and laboratory analyses were performed every six months for three years. Laboratory values included spontaneous overnight GH release, fasting IGF-1 and IGFBP-3. Repeated measures models were used to evaluate interactions among Tanner stage and group (children with CP vs. reference children), taking into account gender, age, and nutritional status. Results Children with CP grew more slowly than those without CP at all Tanner stages (p<0.01). Patterns of IGF-1 and GH secretion in children with CP were similar to those of the reference group; however, the concentrations of IGF-1 (p<0.01) and GH (p<0.01) were lower in girls with CP, with a similar trend for boys (p=0.10 and 0.14, respectively). Conclusions Diminished circulating IGF-1 and GH concentrations may explain the differences in growth between the two groups. PMID:20216931

The effect of pasteurization on transforming growth factor alpha and transforming growth factor beta 2 concentrations in human milk.

PubMed

McPherson, R J; Wagner, C L

2001-01-01

+/- SEM: 99.4+/-6.7% of raw milk, range 79%-120%). In conclusion, both TGF-alpha and TGF-beta2 were well-preserved in whole milk after holder pasteurization at 56.5 degrees C. The relative increase in growth factor concentration in some of the samples may be attributable to the release of that factor from the cellular and/or fat compartments into the aqueous fraction of human milk. These findings have implications regarding use of donor milk as an alternate source of growth factors and cytokines for the newborn gut when mother's milk is unavailable.

Arsenic uptake, transformation, and release by three freshwater algae under conditions with and without growth stress.

PubMed

Xie, Shaowen; Liu, Jinxin; Yang, Fen; Feng, Hanxiao; Wei, Chaoyang; Wu, Fengchang

2018-05-04

This study was carried out using indoor controlled experiments to study the arsenic (As) uptake, biotransformation, and release behaviors of freshwater algae under growth stress. Three freshwater algae, Microcystis aeruginosa, Anabaena flosaquae, and Chlorella sp., were chosen. Two types of inhibitors, e.g., Cu 2+ and isothiazolinone, were employed to inhibit the growth of the algae. The algae were cultivated to a logarithmic stage in growth media containing 0.1 mg/L P; then, 0.8 mg/L As in the form of arsenate (iAs V ) was added, while both inhibitors were simultaneously added at dosages of 0.1 and 0.3 mg/L, with no addition of inhibitors in the control. After 2 days of exposure, the average growth rate (μ 2d ) was measured to represent the growth rates of the algae cells; the extra- and intracellular As concentrations in various forms, i.e., arsenate, arsenite (iAs III ), monomethyl arsenic (MMA), and dimethyl arsenic (DMA), were also measured. Without inhibitors, the average growth rate followed the order of M. aeruginosa, Chlorella sp., and A. flosaquae, with the growth rate of M. aeruginosa significantly higher than that of the other two algae. However, when Cu 2+ was added as an external inhibitor, the order of the average growth rate for the three algae became partially reversed, suggesting differentiation of the algae in response to the inhibitor. This differentiation can be seen by the reduction in the average growth rate of M. aeruginosa, which was as high as 1730% at the 0.3-mg/L Cu 2+ dosage when compared with the control, while for the other two algae, much fewer changes were seen. The great reduction in M. aeruginosa growth rate was accompanied by increases in extracellular iAs V and iAs III and intracellular iAs V concentrations in the algae, indicating that As transformation is related to the growth of this algae. Much fewer or neglectable changes in growth were observed that were consistent with the few changes in the extra- and intracellular

Effects of sodium citrate and acid citrate dextrose solutions on cell counts and growth factor release from equine pure-platelet rich plasma and pure-platelet rich gel.

PubMed

Giraldo, Carlos E; Álvarez, María E; Carmona, Jorge U

2015-03-14

There is a lack information on the effects of the most commonly used anticoagulants for equine platelet rich plasmas (PRPs) elaboration on cell counts and growth factor release from platelet rich gels (PRGs). The aims of this study were 1) to compare the effects of the anticoagulants sodium citrate (SC), acid citrate dextrose solution A (ACD-A) and ACD-B on platelet (PLT), leukocyte (WBC) and on some parameters associated to platelet activation including mean platelet volume (MPV) and platelet distribution width (PDW) between whole blood, pure PRP (P-PRP) and platelet-poor plasma (PPP); 2) to compare transforming growth factor beta 1 (TGF-β(1)) and platelet-derived growth factor isoform BB (PDGF-BB) concentrations in supernatants from pure PRG (P-PRG), platelet-poor gel (PPG), P-PRP lysate (positive control) and plasma (negative control); 3) to establish the possible correlations between all the studied cellular and molecular parameters. In all cases the three anticoagulants produced P-PRPs with significantly higher PLT counts compared with whole blood and PPP. The concentrations of WBCs were similar between P-PRP and whole blood, but significantly lower in PPP. The type of anticoagulant did not significantly affect the cell counts for each blood component. The anticoagulants also did not affect the MPV and PDW parameters. Independently of the anticoagulant used, all blood components presented significantly different concentrations of PDGF-BB and TGF-β(1). The highest growth factor (GF) concentrations were observed from P-PRP lysates, followed by PRG supernatants, PPP lysates, PPG supernatants and plasma. Significant correlations were observed between PLT and WBC counts (ρ = 0.80), PLT count and TGF-β(1) concentration (ρ = 0.85), PLT count and PDGF-BB concentration (ρ = 0.80) and PDGF-BB and TGF-β(1) concentrations (ρ = 0.75). The type of anticoagulant was not correlated with any of the variables evaluated. The anticoagulants did not

Growth factor transgenes interactively regulate articular chondrocytes.

PubMed

Shi, Shuiliang; Mercer, Scott; Eckert, George J; Trippel, Stephen B

2013-04-01

Adult articular chondrocytes lack an effective repair response to correct damage from injury or osteoarthritis. Polypeptide growth factors that stimulate articular chondrocyte proliferation and cartilage matrix synthesis may augment this response. Gene transfer is a promising approach to delivering such factors. Multiple growth factor genes regulate these cell functions, but multiple growth factor gene transfer remains unexplored. We tested the hypothesis that multiple growth factor gene transfer selectively modulates articular chondrocyte proliferation and matrix synthesis. We tested the hypothesis by delivering combinations of the transgenes encoding insulin-like growth factor I (IGF-I), fibroblast growth factor-2 (FGF-2), transforming growth factor beta1 (TGF-β1), bone morphogenetic protein-2 (BMP-2), and bone morphogenetic protien-7 (BMP-7) to articular chondrocytes and measured changes in the production of DNA, glycosaminoglycan, and collagen. The transgenes differentially regulated all these chondrocyte activities. In concert, the transgenes interacted to generate widely divergent responses from the cells. These interactions ranged from inhibitory to synergistic. The transgene pair encoding IGF-I and FGF-2 maximized cell proliferation. The three-transgene group encoding IGF-I, BMP-2, and BMP-7 maximized matrix production and also optimized the balance between cell proliferation and matrix production. These data demonstrate an approach to articular chondrocyte regulation that may be tailored to stimulate specific cell functions, and suggest that certain growth factor gene combinations have potential value for cell-based articular cartilage repair. Copyright © 2012 Wiley Periodicals, Inc.

Growth hormone-releasing hormone stimulates and somatostatin inhibits the release of a novel protein by cultured rat pituitary cells.

PubMed

Tachibana, K; Marquardt, H; Yokoya, S; Friesen, H G

1988-10-01

We have reported that the secretion of at least 17 distinct peptides [including rat (rGH)] GH by cultured rat pituitary cells was stimulated by GH-releasing hormone and inhibited by somatostatin, when analyzed by two-dimensional polyacrylamide gel electrophoresis. Three of these peptides (no. 23, 24, and 25) were not rGH immunoreactive. In order to determine whether these three peptides are fragments, degradation products or posttranscriptionally modified forms of rGH, rGH and peptide no. 23 were characterized structurally. From partial peptide maps of rGH and peptide no. 23 by V8 protease or chymotrypsin, it appeared that these peptides were not related to each other. By N-terminal microsequencing of two-dimensional polyacrylamide gel electrophoresis purified peptide, we have obtained the sequence of 24 N-terminal amino acid residues of peptide no. 23. This sequence has no significant homology with rGH or any other reported protein sequence. Antiserum was generated against a synthetic oligopeptide corresponding to amino acid residues 3-24 of peptide no. 23. The antiserum cross-reacted with peptides no. 23, 24, and 25 upon Western blot analysis. These results indicate that peptide no. 23 has a novel structure unrelated to other pituitary hormones. Since its secretion is influenced by GH-releasing hormone and somatostatin, peptide no. 23 may represent a previously unrecognized structurally unique growth factor.

Vascular Endothelial Growth Factor (VEGF) and Platelet (PF-4) Factor 4 Inputs Modulate Human Microvascular Endothelial Signaling in a Three-Dimensional Matrix Migration Context*

PubMed Central

Hang, Ta-Chun; Tedford, Nathan C.; Reddy, Raven J.; Rimchala, Tharathorn; Wells, Alan; White, Forest M.; Kamm, Roger D.; Lauffenburger, Douglas A.

2013-01-01

The process of angiogenesis is under complex regulation in adult organisms, particularly as it often occurs in an inflammatory post-wound environment. As such, there are many impacting factors that will regulate the generation of new blood vessels which include not only pro-angiogenic growth factors such as vascular endothelial growth factor, but also angiostatic factors. During initial postwound hemostasis, a large initial bolus of platelet factor 4 is released into localized areas of damage before progression of wound healing toward tissue homeostasis. Because of its early presence and high concentration, the angiostatic chemokine platelet factor 4, which can induce endothelial anoikis, can strongly affect angiogenesis. In our work, we explored signaling crosstalk interactions between vascular endothelial growth factor and platelet factor 4 using phosphotyrosine-enriched mass spectrometry methods on human dermal microvascular endothelial cells cultured under conditions facilitating migratory sprouting into collagen gel matrices. We developed new methods to enable mass spectrometry-based phosphorylation analysis of primary cells cultured on collagen gels, and quantified signaling pathways over the first 48 h of treatment with vascular endothelial growth factor in the presence or absence of platelet factor 4. By observing early and late signaling dynamics in tandem with correlation network modeling, we found that platelet factor 4 has significant crosstalk with vascular endothelial growth factor by modulating cell migration and polarization pathways, centered around P38α MAPK, Src family kinases Fyn and Lyn, along with FAK. Interestingly, we found EphA2 correlational topology to strongly involve key migration-related signaling nodes after introduction of platelet factor 4, indicating an influence of the angiostatic factor on this ambiguous but generally angiogenic signal in this complex environment. PMID:24023389

Metabolism of growth hormone releasing peptides.

PubMed

Thomas, Andreas; Delahaut, Philippe; Krug, Oliver; Schänzer, Wilhelm; Thevis, Mario

2012-12-04

New, potentially performance enhancing compounds have frequently been introduced to licit and illicit markets and rapidly distributed via worldwide operating Internet platforms. Developing fast analytical strategies to follow these new trends is one the most challenging issues for modern doping control analysis. Even if reference compounds for the active drugs are readily obtained, their unknown metabolism complicates effective testing strategies. Recently, a new class of small C-terminally amidated peptides comprising four to seven amino acid residues received considerable attention of sports drug testing authorities due to their ability to stimulate growth hormone release from the pituitary. The most promising candidates are the growth hormone releasing peptide (GHRP)-1, -2, -4, -5, -6, hexarelin, alexamorelin, and ipamorelin. With the exemption of GHRP-2, the entity of these peptides represents nonapproved pharmaceuticals; however, via Internet providers, all compounds are readily available. To date, only limited information on the metabolism of these substances is available and merely one metabolite for GHRP-2 is established. Therefore, a comprehensive in vivo (po and iv administration in rats) and in vitro (with human serum and recombinant amidase) study was performed in order to generate information on urinary metabolites potentially useful for routine doping controls. The urine samples from the in vivo experiments were purified by mixed-mode cation-exchange solid-phase extraction and analyzed by ultrahigh-performance liquid chromatography (UHPLC) separation followed by high-resolution/high-accuracy mass spectrometry. Combining the high resolution power of a benchtop Orbitrap mass analyzer for the first metabolite screening and the speed of a quadrupole/time-of-flight (Q-TOF) instrument for identification, urinary metabolites were screened by means of a sensitive full scan analysis and subsequently confirmed by high-accuracy product ion scan experiments. Two

Biomaterials with persistent growth factor gradients in vivo accelerate vascularized tissue formation.

PubMed

Akar, Banu; Jiang, Bin; Somo, Sami I; Appel, Alyssa A; Larson, Jeffery C; Tichauer, Kenneth M; Brey, Eric M

2015-12-01

Gradients of soluble factors play an important role in many biological processes, including blood vessel assembly. Gradients can be studied in detail in vitro, but methods that enable the study of spatially distributed soluble factors and multi-cellular processes in vivo are limited. Here, we report on a method for the generation of persistent in vivo gradients of growth factors in a three-dimensional (3D) biomaterial system. Fibrin loaded porous poly (ethylene glycol) (PEG) scaffolds were generated using a particulate leaching method. Platelet derived growth factor BB (PDGF-BB) was encapsulated into poly (lactic-co-glycolic acid) (PLGA) microspheres which were placed distal to the tissue-material interface. PLGA provides sustained release of PDGF-BB and its diffusion through the porous structure results in gradient formation. Gradients within the scaffold were confirmed in vivo using near-infrared fluorescence imaging and gradients were present for more than 3 weeks. The diffusion of PDGF-BB was modeled and verified with in vivo imaging findings. The depth of tissue invasion and density of blood vessels formed in response to the biomaterial increased with magnitude of the gradient. This biomaterial system allows for generation of sustained growth factor gradients for the study of tissue response to gradients in vivo. Published by Elsevier Ltd.

Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers.

PubMed

Gobburu, J V; Agersø, H; Jusko, W J; Ynddal, L

1999-09-01

To examine the pharmacokinetics (PK) and pharmacodynamics (PD) of ipamorelin, a growth hormone (GH) releasing peptide, in healthy volunteers. A trial was conducted with a dose escalation design comprising 5 different infusion rates (4.21, 14.02, 42.13, 84.27 and 140.45 nmol/kg over 15 minutes) with eight healthy male subjects at each dose level. Concentrations of ipamorelin and growth hormone were measured. The PK parameters showed dose-proportionality, with a short terminal half-life of 2 hours, a clearance of 0.078 L/h/kg and a volume of distribution at steady-state of 0.22 L/kg. The time course of GH stimulation by ipamorelin showed a single episode of GH release with a peak at 0.67 hours and an exponential decline to negligible GH concentration at all doses. The ipamorelin-GH concentration relationship was characterized using an indirect response model and population fitting. The model employed a zero-order GH release rate over a finite duration of time to describe the episodic release of GH. Ipamorelin induces the release of GH at all dose levels with the concentration (SC50) required for half-maximal GH stimulation of 214 nmol/L and a maximal GH production rate of 694 mIU/L/h. The inter-individual variability of the PD parameters was larger than that of the PK parameters. The proposed PK/PD model provides a useful characterization of ipamorelin disposition and GH responses across a range of doses.

Reduced growth factor requirement of keloid-derived fibroblasts may account for tumor growth

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

Russell, S.B.; Trupin, K.M.; Rodriguez-Eaton, S.

Keloids are benign dermal tumors that form during an abnormal wound-healing process is genetically susceptible individuals. Although growth of normal and keloid cells did not differ in medium containing 10% (vol/vol) fetal bovine serum, keloid culture grew to significantly higher densities than normal cells in medium containing 5% (vol/vol) fetal bovine serum, keloid cultures grew to significantly higher densities than normal cells in medium containing 5% (vol/vol) plasma or 1% fetal bovine serum. Conditioned medium from keloid cultures did not stimulate growth of normal cells in plasma nor did it contain detectable platelet-derived growth factor or epidermal growth factor. Keloidmore » fibroblasts responded differently than normal adult fibroblasts to transforming growth factor ..beta... Whereas transforming growth factor ..beta.. reduced growth stimulation by epidermal growth factor in cells from normal adult skin or scars, it enhanced the activity of epidermal growth factor in cells from normal adult skin or scars, it enhanced the activity of epidermal growth factor in cells from keloids. Normal and keloid fibroblasts also responded differently to hydrocortisone: growth was stimulated in normal adult cells and unaffected or inhibited in keloid cells. Fetal fibroblasts resembled keloid cells in their ability to grow in plasma and in their response to hydrocortisone. The ability of keloid fibroblasts to grow to higher cell densities in low-serum medium than cells from normal adult skin or from normal early or mature scars suggests that a reduced dependence on serum growth factors may account for their prolonged growth in vivo. Similarities between keloid and fetal cells suggest that keloids may result from the untimely expression of growth-control mechanism that is developmentally regulated.« less

Investigation of factors affecting in vitro doxorubicin release from PEGylated liposomal doxorubicin for the development of in vitro release testing conditions.

PubMed

Shibata, Hiroko; Izutsu, Ken-Ichi; Yomota, Chikako; Okuda, Haruhiro; Goda, Yukihiro

2015-01-01

Establishing appropriate drug release testing methods of liposomal products for assuring quality and performance requires the determination of factors affecting in vitro drug release. In this study, we investigated the effects of test conditions (human plasma lot, pH/salt concentration in the test media, dilution factor, temperature, ultrasound irradiation, etc.), and liposomal preparation conditions (pH/concentration of ammonium sulfate solution), on doxorubicin (DXR) release from PEGylated liposomal DXR. Higher temperature and lower pH significantly increased DXR release. The evaluation of DXR solubility indicated that the high DXR release induced by low pH may be attributed to the high solubility of DXR at low pH. Ultrasound irradiation induced rapid DXR release in an amplitude-dependent manner. The salt concentration in the test solution, human plasma lot, and dilution factor had a limited impact on DXR-release. Variations in the ammonium sulfate concentration used in solutions for the formation/hydration of liposomes significantly affected DXR release behavior, whereas differences in pH did not. In addition, heating condition in phosphate-buffered saline at lower pH (<6.5) exhibited higher discriminative ability for the release profiles from various liposomes with different concentrations of ammonium sulfate than did ultrasound irradiation. These results are expected to be helpful in the process of establishing appropriate drug release testing methods for PEGylated liposomal DXR.

The Dwarfs of Sindh: severe growth hormone (GH) deficiency caused by a mutation in the GH-releasing hormone receptor gene.

PubMed

Baumann, G; Maheshwari, H

1997-11-01

We report the discovery of a cluster of severe familial dwarfism in two villages in the Province of Sindh in Pakistan. Dwarfism is proportionate and occurs in members of a kindred with a high degree of consanguinity. Only the last generation is affected, with the oldest dwarf being 28 years old. The mode of inheritance is autosomal recessive. Phenotype analysis and endocrine testing revealed isolated growth hormone deficiency (GHD) as the reason for growth failure. Linkage analysis for the loci of several candidate genes yielded a high lod score for the growth hormone-releasing hormone receptor (GHRH-R) locus on chromosome 7. Amplification and sequencing of the GHRH-R gene in affected subjects demonstrated an amber nonsense mutation (GAG-->TAG; Glu50-->Stop) in exon 3. The mutation, in its homozygous form, segregated 100% with the dwarf phenotype. It predicts a truncation of the GHRH-R in its extracellular domain, which is likely to result in a severely disabled or non-existent receptor protein. Subjects who are heterozygous for the mutation show mild biochemical abnormalities in the growth hormone-releasing hormone (GHRH)--growth hormone--insulin-like growth factor axis, but have only minimal or no growth retardation. The occurrence of an offspring of two dwarfed parents indicates that the GHRH-R is not necessary for fertility in either sex. We conclude that Sindh dwarfism is caused by an inactivating mutation in the GHRH-R gene, resulting in the inability to transmit a GHRH signal and consequent severe isolated GHD.

Crop-tree release increases growth of 12-year-old yellow-poplar and black cherry

Treesearch

Neil I. Lamson; H. Clay Smith; H. Clay Smith

1989-01-01

Precommercial thinning was done in a 12-year-old Appalachian hardwood sapling stand in West Virginia. Two crop-tree release techniques were used--crown touching and crown touching plus 5 feet. Results indicated that both treatments significantly increased 5-year d.b.h. growth for released yellow-poplar and black cherry crop trees. Although there was a major increase in...

Factors Released from Endothelial Cells Exposed to Flow Impact Adhesion, Proliferation, and Fate Choice in the Adult Neural Stem Cell Lineage.

PubMed

Dumont, Courtney M; Piselli, Jennifer M; Kazi, Nadeem; Bowman, Evan; Li, Guoyun; Linhardt, Robert J; Temple, Sally; Dai, Guohao; Thompson, Deanna M

2017-08-15

The microvasculature within the neural stem cell (NSC) niche promotes self-renewal and regulates lineage progression. Previous work identified endothelial-produced soluble factors as key regulators of neural progenitor cell (NPC) fate and proliferation; however, endothelial cells (ECs) are sensitive to local hemodynamics, and the effect of this key physiological process has not been defined. In this study, we evaluated adult mouse NPC response to soluble factors isolated from static or dynamic (flow) EC cultures. Endothelial factors generated under dynamic conditions significantly increased neuronal differentiation, while those released under static conditions stimulated oligodendrocyte differentiation. Flow increases EC release of neurogenic factors and of heparin sulfate glycosaminoglycans that increase their bioactivity, likely underlying the enhanced neuronal differentiation. Additionally, endothelial factors, especially from static conditions, promoted adherent growth. Together, our data suggest that blood flow may impact proliferation, adhesion, and the neuron-glial fate choice of adult NPCs, with implications for diseases and aging that reduce flow.

Epidermal growth factor inhibits rat pancreatic cell proliferation, causes acinar cell hypertrophy, and prevents caerulein-induced desensitization of amylase release.

PubMed

Morisset, J; Larose, L; Korc, M

1989-06-01

The in vivo effects of epidermal growth factor (EGF) on pancreatic growth and digestive enzyme concentrations were compared with the actions of the pancreatic secretagogue caerulein in the adult rat. EGF (10 micrograms/kg BW) did not alter pancreatic weight or protein content. However, this concentration of EGF inhibited [3H]thymidine incorporation into DNA by 44%, decreased DNA content by 20%, and increased the concentrations of amylase, chymotrypsinogen, and protein by 106%, 232%, and 42%, respectively. Pancreatic acini prepared from EGF-treated rats exhibited a characteristic secretory response to caerulein that was superimposable to that obtained in acini from saline-treated rats. In both groups of acini half-maximal and maximal stimulation of amylase release occurred at approximately 5 pM and 50 pM caerulein, respectively. In contrast to EGF, caerulein (1 microgram/kg BW) increased pancreatic weight by 29% and protein content by 59%, and enhanced [3H]thymidine incorporation into DNA by 70%. Although caerulein increased the concentrations of pancreatic amylase and chymotrypsinogen by 38% and 297%, respectively, pancreatic acini prepared from caerulein-treated rats were less sensitive to the actions of caerulein in vitro when compared with acini from control rats. Indeed, the EC50 was shift from 4.8 pM to 9.8 pM after 4 days of treatment. EGF potentiated the actions of caerulein on pancreatic weight, protein content, and chymotrypsinogen concentration, and prevented the caerulein-induced alteration in the secretory responsiveness of the acinar cell. Conversely, caerulein reversed the inhibitory effect of EGF on thymidine incorporation. These findings suggest that EGF may modulate the trophic effects of certain gastrointestinal hormones, and may participate in the regulation of pancreatic exocrine function in vivo.

Role of pH Changes on Transforming Growth Factor-β1 Release and on the Fibrin Architecture of Platelet-rich Fibrin When Layered with Biodentine, Glass Ionomer Cement, and Intermediate Restorative Material.

PubMed

Mullaguri, Harish; Suresh, Nandini; Surendran, Smitha; Velmurugan, Natanasabapathy; Chitra, Selvarajan

2016-05-01

The purpose of this study was to evaluate the influence of pH that is due to setting reaction of Biodentine, glass ionomer cement (GIC), and intermediate restorative material (IRM) on transforming growth factor-β1 (TGF-β1) release and on the fibrin architecture of platelet-rich fibrin (PRF). PRF was obtained from 8 volunteers and layered over the freshly prepared GIC, IRM, and Biodentine mixtures. TGF-β1 release was estimated by using enzyme-linked immunosorbent assay (ELISA), and fibrin structure of PRF was analyzed by using scanning electron microscope at 1 and 5 hours. Biodentine, GIC, and IRM increased the TGF-β1 release in comparison with that of control group (PRF alone) at both 1 and 5 hours. Biodentine released significantly more TGF-β1 than GIC and IRM at 1 hour. At 5 hours both GIC and Biodentine released significantly more TGF-β1 than IRM. The fibrin architecture of the Biodentine group was similar to that of control group at both 1 and 5 hours. In GIC and IRM groups the fibrillar structure of fibrin was collapsed, ill-defined, and cloudy with very thick fibers and irregularly reduced porosities. Biodentine induces larger amount of TGF-β1 release and also maintains the integrity of fibrin structure when compared with GIC and IRM when layered over PRF. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Effect of thyrotropin-releasing factor on serum thyroid-stimulating hormone

PubMed Central

Costom, Bruce H.; Grumbach, Melvin M.; Kaplan, Selna L.

1971-01-01

To test the hypothesis that the primary defect in some patients with idiopathic hypopituitary dwarfism is failure to secrete hypothalamic hypophysiotropic-releasing factors, synthetic thyrotropin-releasing factor (TRF), 500 μg, wa given intravenously, and timed venous samples obtained for determination of the concentration of plasma TSH by radioimmunoassay in three groups of subjects: (a) 11 patients without evidence of endocrine or systemic disease, (group I) (b) 8 with isolated growth hormone deficiency and normal thyroid function, (group II) and (c) 9 patients with idiopathic hypopituitary dwarfism and thyroid-stimulating hormone (TSH) deficiency (group III). The mean fasting plasma TSH value was 4.1 μU/ml in group I, and 3.9 μU/ml in group II; in both groups there was a brisk rise in plasma TSH to peak levels of 12-45 μU/ml at 30-45 min, and a fall toward base line levels at 120 min. All children in group III had basal TSH levels of < 1.5 μU/ml; one failed to respond to TRF; eight exhibited a rise in plasma TSH with peak values comparable with those in groups I and II. In four of eight children in group III who responded to TRF, the TSH response was delayed and the initial rise in plasma TSH was not detectable until 10-60 min. In these four patients, plasma TSH levels continued to rise at 120 min. The mean fasting concentration of plasma thyroxine iodide (T4) in subjects with normal thyroid function (groups I and II) was 5.6 μg/100 ml, and the mean plasma T4 level at 120 min was 6.6 μg/100 ml. This difference between fasting and postTRF plasma T4 was significant (P < 0.001) by paired analysis. Mean fasting plasma T4 concentration in group III patients was 1.3 μg/100 ml; after TRF a significant rise in T4 concentration was not detected in this group. The results indicate that TRF test is useful in distinguishing between primary hypothalamic and pituitary forms of TSH deficiency. In light of the evidence of TRF deficiency in eight of nine patients with

Mechanical perturbation-induced ethylene releases apical dominance in Pharbitis nil by restricting shoot growth

NASA Technical Reports Server (NTRS)

Prasad, T. K.; Cline, M. G.

1985-01-01

Mechanical perturbation (MP, rubbing) or internodes of Pharbitis nil shoots initiates release of lateral buds (LB) from apical dominance within 48 h. Evidence is presented which suggests that MP promotion of LB outgrowth is mediated by ethylene-induced restriction of main shoot growth. Ethylene production in the internodes is stimulated by MP within 2 h. Effects of MP are mimicked by treatments with 1-aminocyclopropane-1-carboxylic acid (ACC) and are negated by the inhibitors of ethylene production or action, aminoethoxy vinylglycine (AVG) and AgNO3. The fact that effects of MP, ACC, and ethylene inhibitors are observed to occur on main shoot growth at least 24 h before they are observed to occur on LB growth suggests a possible cause and effect relationship. MP also causes an increase in internode diameter. MP stimulation of ethylene production appears to be mediated by ACC synthase. The results of this study and our previous studies suggest that apical dominance may be released by any mechanism which induces ethylene restriction of main shoot growth.

Treatment of periorbital edema with human corticotropin-releasing factor after blepharoplasty.

PubMed

Schendel, S A; Stephanides, M

1996-03-01

This prospective study of 32 patients was undertaken to ev evaluate the formation of postoperative periorbital edema after administration of human corticotropin-releasing factor (hCRF). Human corticotropin-releasing factor has strong antiedematous properties as a result of direct action on blood vessels independent of endocrine function and has been shown to have a positive effect on vascular permeability in animal studies independent of corticosteroid effects. Human corticotropin-releasing factor was administered intravenously preoperatively to patients undergoing blepharoplasty in doses of 2, 4, and 8 mu g/kg body weight as a randomized, double-blind, placebo-controlled study. The periorbital edema was measured by the use of a three-dimensional laser scanner to determine facial and eyelid volume changes as specified times postoperatively. Human corticotropin-releasing factor was well tolerated when administered intravenously over a ten-minute period to healthy patients undergoing blepharoplasty. Mild transitory flushing and hypotension were the most common adverse events. Transient decreases in systolic and diastolic blood pressure and increases in heart rate occurred at hCRF doses greater than 2 mu g/kg and were most prominent at 8 mu g/kg. The 8 mu g/kg hCRF dose also showed a trend toward less postoperative edema but this was not statistically significant at the p<0.05 level. Human corticotropin-releasing factor appears to be safe for intravenous use in patients undergoing blepharoplasty; however, its efficacy in reducing postoperative edema as a single preoperative administration was not conclusively demonstrated in this study. Further research with a larger study population and other dosing regimens is indicated.

Down-regulation of connective tissue growth factor by inhibition of transforming growth factor beta blocks the tumor-stroma cross-talk and tumor progression in hepatocellular carcinoma.

PubMed

Mazzocca, Antonio; Fransvea, Emilia; Dituri, Francesco; Lupo, Luigi; Antonaci, Salvatore; Giannelli, Gianluigi

2010-02-01

Tumor-stroma interactions in hepatocellular carcinoma (HCC) are of key importance to tumor progression. In this study, we show that HCC invasive cells produce high levels of connective tissue growth factor (CTGF) and generate tumors with a high stromal component in a xenograft model. A transforming growth factor beta (TGF-beta) receptor inhibitor, LY2109761, inhibited the synthesis and release of CTGF, as well as reducing the stromal component of the tumors. In addition, the TGF-beta-dependent down-regulation of CTGF diminished tumor growth, intravasation, and metastatic dissemination of HCC cells by inhibiting cancer-associated fibroblast proliferation. By contrast, noninvasive HCC cells were found to produce low levels of CTGF. Upon TGF-beta1 stimulation, noninvasive HCC cells form tumors with a high stromal content and CTGF expression, which is inhibited by treatment with LY2109761. In addition, the acquired intravasation and metastatic spread of noninvasive HCC cells after TGF-beta1 stimulation was blocked by LY2109761. LY2109761 interrupts the cross-talk between cancer cells and cancer-associated fibroblasts, leading to a significant reduction of HCC growth and dissemination. Interestingly, patients with high CTGF expression had poor prognosis, suggesting that treatment aimed at reducing TGF-beta-dependent CTGF expression may offer clinical benefits. Taken together, our preclinical results indicate that LY2109761 targets the cross-talk between HCC and the stroma and provide a rationale for future clinical trials.

Growth factors, nutrient signaling, and cardiovascular aging

PubMed Central

Fontana, Luigi; Vinciguerra, Manlio; Longo, Valter D.

2012-01-01

Growth factors regulated by specific macronutrients have been shown to promote aging and accelerate mortality in the great majority of the organisms studied. In particular, the enzymes activated by growth hormone (GH), insulin and insulin-like growth factor 1 (IGF-I) in mammals and their orthologs in simple model organisms represent perhaps the best-understood proteins involved in the aging process. Dietary restriction (DR), which reduces the level of IGF-I and of other growth factors, has been associated with protection from diabetes, cancer, and cardiovascular diseases and deficiencies in GH signaling and IGF-I are strongly associated with protection from cancer and diabetes in both mice and humans, but their role in cardiac function and cardiovascular diseases is controversial. Here we review the link between growth factors, cardiac function and heart disease with focus on the cardioprotective and sensitizing effect of growth factors in both model organisms and humans. PMID:22499903

Potentiation of cytotoxic chemotherapy by growth hormone-releasing hormone agonists.

PubMed

Jaszberenyi, Miklos; Rick, Ferenc G; Popovics, Petra; Block, Norman L; Zarandi, Marta; Cai, Ren-Zhi; Vidaurre, Irving; Szalontay, Luca; Jayakumar, Arumugam R; Schally, Andrew V

2014-01-14

The dismal prognosis of malignant brain tumors drives the development of new treatment modalities. In view of the multiple activities of growth hormone-releasing hormone (GHRH), we hypothesized that pretreatment with a GHRH agonist, JI-34, might increase the susceptibility of U-87 MG glioblastoma multiforme (GBM) cells to subsequent treatment with the cytotoxic drug, doxorubicin (DOX). This concept was corroborated by our findings, in vivo, showing that the combination of the GHRH agonist, JI-34, and DOX inhibited the growth of GBM tumors, transplanted into nude mice, more than DOX alone. In vitro, the pretreatment of GBM cells with JI-34 potentiated inhibitory effects of DOX on cell proliferation, diminished cell size and viability, and promoted apoptotic processes, as shown by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide proliferation assay, ApoLive-Glo multiplex assay, and cell volumetric assay. Proteomic studies further revealed that the pretreatment with GHRH agonist evoked differentiation decreasing the expression of the neuroectodermal stem cell antigen, nestin, and up-regulating the glial maturation marker, GFAP. The GHRH agonist also reduced the release of humoral regulators of glial growth, such as FGF basic and TGFβ. Proteomic and gene-expression (RT-PCR) studies confirmed the strong proapoptotic activity (increase in p53, decrease in v-myc and Bcl-2) and anti-invasive potential (decrease in integrin α3) of the combination of GHRH agonist and DOX. These findings indicate that the GHRH agonists can potentiate the anticancer activity of the traditional chemotherapeutic drug, DOX, by multiple mechanisms including the induction of differentiation of cancer cells.

Neurotrophins, growth-factor-regulated genes and the control of energy balance.

PubMed

Salton, Stephen R J

2003-03-01

Neurotrophic growth factors are proteins that control neuronal differentiation and survival, and consequently play important roles in the developing and adult stages of the nervous system. Study of the genes that are regulated by these growth factors has provided insight into the proteins that are critical to the maturation of the nervous system, suggesting that select neurotrophins may play a role in the control of body homeostasis by the brain and peripheral nervous system. Our understanding of the mechanisms of action of neurotrophic growth factors has increased through experimental manipulation of cultured neurons and neuronal cell lines. In particular, the PC12 pheochromocytoma cell line, which displays many properties of adrenal chromaffin cells and undergoes differentiation into sympathetic neuron-like cells when treated with nerve growth factor, has been extensively investigated to identify components of neurotrophin signaling pathways as well as the genes that they regulate. VGF was one of the first neurotrophin-regulated clones identified in NGF-treated PC12 cells. Subsequent studies indicate that the vgf gene is regulated in vivo in the nervous system by neurotrophins, by electrical activity, in response to injury or seizure, and by feeding and the circadian clock. The vgf gene encodes a polypeptide rich in paired basic amino acids; this polypeptide is differentially processed in neuronal and neuroendocrine cells and is released via the regulated secretory pathway. Generation and analysis of knockout mice that fail to synthesize VGF indicate that this protein plays a critical, non-redundant role in the regulation of energy homeostasis, providing a possible link between neurotrophin function in the nervous system and the peripheral control of feeding and metabolic activity. Future experiments should clarify the sites and mechanisms of action of this neurotrophin-regulated neuronal and neuroendocrine protein.

Release of Cyclic Phosphatidic Acid from Gelatin-based Hydrogels Inhibit Colon Cancer Cell Growth and Migration

PubMed Central

Tsukahara, Tamotsu; Murakami-Murofushi, Kimiko

2012-01-01

Microparticle and nanoparticle formulations are widely used to improve the bioavailability of low-solubility drugs and as vehicles for organ- and tissue-specific targeted drug delivery. We investigated the effect of a novel, controlled-release form of a bioactive lipid, cyclic phosphatidic acid (cPA), on human colon cancer cell line functions. We encapsulated cPA in gelatin-based hydrogels and examined its ability to inhibit the viability and migration of HT-29 and DLD-1 cells in vitro and the LPA-induced activity of the transcription factor peroxisome proliferator-activated receptor gamma (PPARγ). The hydrogel delivery system prolonged cPA release into the culture medium. Accordingly, cPA-hydrogel microspheres substantially inhibited LPA-induced PPARγ activity and cell growth and migration compared with that of cells cultured with cPA alone. Thus, hydrogel microspheres are a potential system for stable and efficient delivery of bioactive lipids such as cPA and may offer a new strategy for targeted colon cancer treatment. PMID:23008752

Role of epidermal growth factor and transforming growth factor α in the developing stomach

PubMed Central

Kelly, E; Newell, S; Brownlee, K; Farmery, S; Cullinane, C; Reid, W; Jackson, P; Gray, S; Primrose, J; Lagopoulos, M

1997-01-01

AIMS—To determine whether epidermal growth factor (EGF) or the related transforming growth factor α (TGFα) may have a role in the developing human stomach; to substantiate the presence of EGF in human liquor in the non-stressed infant and whether EGF in amniotic fluid is maternally or fetally derived.
METHODS—The temporal expression and localisation of EGF, TGFα, and their receptors during fetal and neonatal life were examined in 20 fetal and five infant stomachs. Simultaneously, samples of amniotic fluid and fetal urine from 10 newborn infants were collected and assayed for EGF by radioimmunoassay.
RESULTS—EGF immunoreactivity was not noted in any of the specimens examined. In contrast, TGFα immunoreactivity was shown in mucous cells from 18 weeks of gestation onwards. EGF receptor immunoreactivity was seen on superficial mucous cells in gastric mucosa from 18 weeks of gestation onwards. The median concentration of EGF was 30 and 8.5 pg/ml in amniotic fluid and fetal urine, respectively, suggesting that EGF is not produced by the fetus.
CONCLUSIONS—This study adds weight to the hypothesis that swallowed EGF, probably produced by the amniotic membranes, and locally produced TGFα, may have a role in the growth and maturation of the human stomach.

 Keywords: epidermal growth factor; transforming growth factor α; EGF receptors; stomach PMID:9175944

Preparation and features of polycaprolactone vascular grafts with the incorporated vascular endothelial growth factor

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

Sevostyanova, V. V., E-mail: sevostyanova.victoria@gmail.com; Khodyrevskaya, Y. I.; Glushkova, T. V.

The development of tissue-engineered small-diameter vascular grafts is an urgent issue in cardiovascular surgery. In this study, we assessed how the incorporation of the vascular endothelial growth factor (VEGF) affects morphological and mechanical properties of polycaprolactone (PCL) vascular grafts along with its release kinetics. Vascular grafts were prepared using two-phase electrospinning. In pursuing our aims, we performed scanning electron microscopy, mechanical testing, and enzyme-linked immunosorbent assay. Our results demonstrated the preservation of a highly porous structure and improvement of PCL/VEGF scaffold mechanical properties as compared to PCL grafts. A prolonged VEGF release testifies the use of this construct as amore » scaffold for tissue-engineered vascular grafts.« less

S100A13-C2A binary complex structure-a key component in the acidic fibroblast growth factor for the non-classical pathway

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

Mohan, Sepuru K.; Rani, Sandhya G.; Kumar, Sriramoju M.

2009-03-13

Fibroblast growth factors (FGFs) are key regulators of cell proliferation, differentiation, tumor-induced angiogenesis and migration. FGFs are essential for early embryonic development, organ formation and angiogenesis. They play important roles in tumor formation, inflammation, wound healing and restenosis. The biological effects of FGFs are mediated through the activation of the four transmembrane phosphotyrosine kinase receptors (FGFRs) in the presence of heparin sulfate proteoglycans (HSPGs) and therefore require the release of FGFs into the extracellular space. However, FGF-1 lacks the signal peptide required for the releasing of these proteins through the classical endoplasmic reticulum (ER)-Golgi secretary pathway. Maciag et al. demonstratedmore » that FGF-1 is exported through a non-classical release pathway involving the formation of a specific multiprotein complex [M. Landriscina, R. Soldi, C. Bagala, I. Micucci, S. Bellum, F. Tarantini, I. Prudovsky, T. Maciag, S100A13 participates in the release of fibroblast growth factor 1 in response to heat shock in vitro, J. Biol. Chem. 276 (2001) 22544-22552; C.M. Carreira, T.M. LaVallee, F. Tarantini, A. Jackson, J.T. Lathrop, B. Hampton, W.H. Burgess, T. Maciag, S100A13 is involved in the regulation of fibroblast growth factor-1 and p40 synaptotagmin-1 release in vitro, J. Biol. Chem. 273 (1998) 22224-22231; T.M. LaValle, F. Tarantini, S. Gamble, C.M. Carreira, A. Jackson, T. Maciag, Synaptotagmin-1 is required for fibroblast growth factor-1 release, J. Biol. Chem. 273 (1998) 22217-22223; C. Bagala, V. Kolev, A. Mandinova, R. Soldi, C. Mouta, I. Graziani, I, Prudovsky, T. Maciag, The alternative translation of synaptotagmin 1 mediates the non-classical release of FGF1, Biochem. Biophys. Res. Commun. 310 (2003) 1041-1047]. The protein constituents of this complex include FGF-1, S100A13 (a Ca{sup 2+}-binding protein), and the p40 form of synaptotagmin 1 (Syt1). To understand the molecular events in the FGF-1

Further characterization of [3H]gamma-aminobutyric acid release from isolated neuronal growth cones: role of intracellular Ca2+ stores.

PubMed

Lockerbie, R O; Gordon-Weeks, P R

1986-04-01

We have recently shown that growth cones isolated from neonatal rat forebrain possess uptake and release mechanisms for the neurotransmitter gamma-aminobutyric acid. About half of the K+-induced release of [3H]gamma-aminobutyric acid from isolated growth cones is dependent on extracellular Ca2+. The remaining component of the [3H]gamma-aminobutyric acid release is unaffected by removal of extracellular Ca2+ and is resistant to blockade by the voltage-sensitive Ca2+-channel blocker methoxyverapamil. In the present series of experiments we have used caffeine to assess the possible role of intracellular stores of Ca2+ in supporting that component of the K+-induced release of [3H]gamma-aminobutyric acid from isolated growth cones that is independent of extracellular Ca2+. We have chosen caffeine because of its well established effect of releasing Ca2+ from smooth endoplasmic reticulum in muscle. We found that caffeine can release [3H]gamma-aminobutyric acid from isolated growth cones. This effect persists in Ca2+-free medium, in the presence of methoxyverapamil and in the absence of Na+. Furthermore, isobutylmethylxanthine could not substitute for caffeine suggesting that the caffeine effect is not due to phosphodiesterase inhibition and the subsequent rise in intracellular cyclic nucleotides. A combination of the mitochondrial poisons, Antimycin A and sodium azide had no effect on the release of [3H]gamma-aminobutyric acid induced either by caffeine or by high K+. We conclude that caffeine causes the release of Ca2+ from a non-mitochondrial store within the growth cone and that this Ca2+ store supports that component of the K+-induced release of [3H]gamma-aminobutyric acid that is independent of extracellular Ca2+.

Evaluation of the Effect of Platelet-Released Growth Factor and Immediate Orthodontic Loading on the Removal Torque of Miniscrews.

PubMed

Bayani, Shahin; Masoomi, Fatemeh; Aghaabbasi, Sharereh; Farsinejad, Alireza

2016-01-01

The purpose of this study was to evaluate the effect of platelet-released growth factor (PRGF) and immediate orthodontic forces on the removal torque of miniscrews. This study was conducted on three male dogs aged 6 to 8 months with a body weight of 17.6 to 18.4 kg. Sixty miniscrews were inserted in the posterior aspect of the femur. There were four groups, including loaded miniscrews with application of PRGF, unloaded miniscrews without application of PRGF, unloaded miniscrews with PRGF, and loaded miniscrews without PRGF. Twenty miniscrews were inserted in the femoral bone of one foot of each dog, including all the aforementioned subgroups. After 12 weeks, the miniscrews were removed by a removal torque tester device and measured in newton centimeters. The mean removal torque values in four groups of immediately loaded screws with PRGF, unloaded screws with PRGF, immediately loaded screws without PRGF, and unloaded screws without PRGF were 19.68, 21.74, 13.65, and 15.46 Ncm, respectively. It was shown that the mean removal torque value for the group with PRGF was significantly higher than that in the other groups (P = .0001). Although there was a tendency toward a decrease in removal torque value with immediate loading, it was not statistically significant (P = .21). According to the results of this study, applying PRGF with miniscrews increased their stability, but the delivery of immediate force on miniscrews had no effect on the miniscrews' stability.

Effect of Nisin's Controlled Release on Microbial Growth as Modeled for Micrococcus luteus.

PubMed

Balasubramanian, Aishwarya; Lee, Dong Sun; Chikindas, Michael L; Yam, Kit L

2011-06-01

The need for safe food products has motivated food scientists and industry to find novel technologies for antimicrobial delivery for improving food safety and quality. Controlled release packaging is a novel technology that uses the package to deliver antimicrobials in a controlled manner and sustain antimicrobial stress on the targeted microorganism over the required shelf life. This work studied the effect of controlled release of nisin to inhibit growth of Micrococcus luteus (a model microorganism) using a computerized syringe pump system to mimic the release of nisin from packaging films which was characterized by an initially fast rate and a slower rate as time progressed. The results show that controlled release of nisin was strikingly more effective than instantly added ("formulated") nisin. While instant addition experiments achieved microbial inhibition only at the beginning, controlled release experiments achieved complete microbial inhibition for a longer time, even when as little as 15% of the amount of nisin was used as compared to instant addition.

Hyperphagia in male melanocortin 4 receptor deficient mice promotes growth independently of growth hormone.

PubMed

Tan, H Y; Steyn, F J; Huang, L; Cowley, M; Veldhuis, J D; Chen, C

2016-12-15

Loss of function of the melanocortin 4 receptor (MC4R) results in hyperphagia, obesity and increased growth. Despite knowing that MC4Rs control food intake, we are yet to understand why defects in the function of the MC4R receptor contribute to rapid linear growth. We show that hyperphagia following germline loss of MC4R in male mice promotes growth while suppressing the growth hormone-insulin-like growth factor-1 (GH-IGF-1) axis. We propose that hyperinsulinaemia promotes growth while suppressing the GH-IGF-1 axis. It is argued that physiological responses essential to maintain energy flux override conventional mechanisms of pubertal growth to promote the storage of excess energy while ensuring growth. Defects in melanocortin-4-receptor (MC4R) signalling result in hyperphagia, obesity and increased growth. Clinical observations suggest that loss of MC4R function may enhance growth hormone (GH)-mediated growth, although this remains untested. Using male mice with germline loss of the MC4R, we assessed pulsatile GH release and insulin-like growth factor-1 (IGF-1) production and/or release relative to pubertal growth. We demonstrate early-onset suppression of GH release in rapidly growing MC4R deficient (MC4RKO) mice, confirming that increased linear growth in MC4RKO mice does not occur in response to enhanced activation of the GH-IGF-1 axis. The progressive suppression of GH release in MC4RKO mice occurred alongside increased adiposity and the progressive worsening of hyperphagia-associated hyperinsulinaemia. We next prevented hyperphagia in MC4RKO mice through restricting calorie intake in these mice to match that of wild-type (WT) littermates. Pair feeding of MC4RKO mice did not prevent increased adiposity, but attenuated hyperinsulinaemia, recovered GH release, and normalized linear growth rate to that seen in pair-fed WT littermate controls. We conclude that the suppression of GH release in MC4RKO mice occurs independently of increased adipose mass, and is a

Growth Factor FGF2 Cooperates with Interleukin-17 to Repair Intestinal Epithelial Damage.

PubMed

Song, Xinyang; Dai, Dai; He, Xiao; Zhu, Shu; Yao, Yikun; Gao, Hanchao; Wang, Jingjing; Qu, Fangfang; Qiu, Ju; Wang, Honglin; Li, Xiaoxia; Shen, Nan; Qian, Youcun

2015-09-15

The intestinal epithelial barrier plays a critical role in the mucosal immunity. However, it remains largely unknown how the epithelial barrier is maintained after damage. Here we show that growth factor FGF2 synergized with interleukin-17 (IL-17) to induce genes for repairing of damaged epithelium. FGF2 or IL-17 deficiency resulted in impaired epithelial proliferation, increased pro-inflammatory microbiota outgrowth, and consequently worse pathology in a DSS-induced colitis model. The dysregulated microbiota in the model induced transforming growth factor beta 1 (TGFβ1) expression, which in turn induced FGF2 expression mainly in regulatory T cells. Act1, an essential adaptor in IL-17 signaling, suppressed FGF2-induced ERK activation through binding to adaptor molecule GRB2 to interfere with its association with guanine nucleotide exchange factor SOS1. Act1 preferentially bound to IL-17 receptor complex, releasing its suppressive effect on FGF2 signaling. Thus, microbiota-driven FGF2 and IL-17 cooperate to repair the damaged intestinal epithelium through Act1-mediated direct signaling cross-talk. Copyright © 2015 Elsevier Inc. All rights reserved.

Hydrogen sulfide-releasing naproxen suppresses colon cancer cell growth and inhibits NF-κB signaling.

PubMed

Kodela, Ravinder; Nath, Niharika; Chattopadhyay, Mitali; Nesbitt, Diandra E; Velázquez-Martínez, Carlos A; Kashfi, Khosrow

2015-01-01

Colorectal cancer (CRC) is the second leading cause of death due to cancer and the third most common cancer in men and women in the USA. Nuclear factor kappa B (NF-κB) is known to be activated in CRC and is strongly implicated in its development and progression. Therefore, activated NF-κB constitutes a bona fide target for drug development in this type of malignancy. Many epidemiological and interventional studies have established nonsteroidal anti-inflammatory drugs (NSAIDs) as a viable chemopreventive strategy against CRC. Our previous studies have shown that several novel hydrogen sulfide-releasing NSAIDs are promising anticancer agents and are safer derivatives of NSAIDs. In this study, we examined the growth inhibitory effect of a novel H2S-releasing naproxen (HS-NAP), which has a repertoire as a cardiovascular-safe NSAID, for its effects on cell proliferation, cell cycle phase transitions, and apoptosis using HT-29 human colon cancer cells. We also investigated its effect as a chemo-preventive agent in a xenograft mouse model. HS-NAP suppressed the growth of HT-29 cells by induction of G0/G1 arrest and apoptosis and downregulated NF-κB. Tumor xenografts in mice were significantly reduced in volume. The decrease in tumor mass was associated with a reduction of cell proliferation, induction of apoptosis, and decreases in NF-κB levels in vivo. Therefore, HS-NAP demonstrates strong anticancer potential in CRC.

Comparison of human dermal fibroblasts (HDFs) growth rate in culture media supplemented with or without basic fibroblast growth factor (bFGF).

PubMed

Abdian, Narges; Ghasemi-Dehkordi, Payam; Hashemzadeh-Chaleshtori, Morteza; Ganji-Arjenaki, Mahbobe; Doosti, Abbas; Amiri, Beheshteh

2015-12-01

Basic fibroblast growth factor (bFGF or FGF-2) is a member of the FGF family secreted by different kinds of cells like HDFs and it is an important nutritional factor for cell growth and differentiation. The HDFs release bFGF in culture media at very low. The present study aims to investigate the HDFs growth rate in culture media supplemented either with or without bFGF. In brief, HDFs were isolated from human foreskin sample and were cultured in vitro in media containing bFGF and lack of this factor. The cells growth rate was calculated by trypan blue. The karyotyping was performed using G-banding to investigate the chromosomal abnormality of HDFs in both groups. Total RNA of each groups were extracted and cDNA samples were synthesized then, real-time Q-PCR was used to measure the expression level of p27kip1 and cyclin D1 genes normalized to internal control gene (GAPDH). The karyotype analysis showed that HDFs cultured in media or without bFGF had normal karyotype (46 chromosomes, XY) and chromosomal abnormalities were not observed. The cell growth rates in both groups were normal with proliferated exponentially but the slope of growth curve in HDFs cultured in media containing bFGF was increased. Karyotyp test showed that bFGF does not affect on cytogenetic stability of cells. The survey of p27kip1 and cyclin D1 genes by real-time Q-PCR showed that the expression level of these genes were up-regulated when adding bFGF in culture media (p < 0.05). The findings of the present study demonstrate that appropriate supplementation of culture media with growth factor like bFGF could enhance the proliferation and differentiation capacity of cells and improve cells growth rate. Similarly, fibroblast growth factors did not induce any chromosomal abnormality in cells. Furthermore, in HDFs cultured in bFGF supplemented media, the p27kip1 and cyclin D1 genes were up-regulated and suggesting an important role for bFGF in cell-cycle regulation and progression and fibroblast

Growth factor and pro-inflammatory cytokine contents in platelet-rich plasma (PRP), plasma rich in growth factors (PRGF), advanced platelet-rich fibrin (A-PRF), and concentrated growth factors (CGF).

PubMed

Masuki, Hideo; Okudera, Toshimitsu; Watanebe, Taisuke; Suzuki, Masashi; Nishiyama, Kazuhiko; Okudera, Hajime; Nakata, Koh; Uematsu, Kohya; Su, Chen-Yao; Kawase, Tomoyuki

2016-12-01

The development of platelet-rich fibrin (PRF) drastically simplified the preparation procedure of platelet-concentrated biomaterials, such as platelet-rich plasma (PRP), and facilitated their clinical application. PRF's clinical effectiveness has often been demonstrated in pre-clinical and clinical studies; however, it is still controversial whether growth factors are significantly concentrated in PRF preparations to facilitate wound healing and tissue regeneration. To address this matter, we performed a comparative study of growth factor contents in PRP and its derivatives, such as advanced PRF (A-PRF) and concentrated growth factors (CGF). PRP and its derivatives were prepared from the same peripheral blood samples collected from healthy donors. A-PRF and CGF preparations were homogenized and centrifuged to produce extracts. Platelet and white blood cell counts in A-PRF and CGF preparations were determined by subtracting those counts in red blood cell fractions, supernatant acellular serum fractions, and A-PRF/CGF exudate fractions from those counts of whole blood samples. Concentrations of growth factors (TGF-β1, PDGF-BB, VEGF) and pro-inflammatory cytokines (IL-1β, IL-6) were determined using ELISA kits. Compared to PRP preparations, both A-PRF and CGF extracts contained compatible or higher levels of platelets and platelet-derived growth factors. In a cell proliferation assay, both A-PRF and CGF extracts significantly stimulated the proliferation of human periosteal cells without significant reduction at higher doses. These data clearly demonstrate that both A-PRF and CGF preparations contain significant amounts of growth factors capable of stimulating periosteal cell proliferation, suggesting that A-PRF and CGF preparations function not only as a scaffolding material but also as a reservoir to deliver certain growth factors at the site of application.

Growth factors, muscle function, and doping.

PubMed

Goldspink, Geoffrey; Wessner, Barbara; Tschan, Harald; Bachl, Norbert

2010-03-01

This article discusses the inevitable use of growth factors for enhancing muscle strength and athletic performance. Much effort has been expended on developing a treatment of muscle wasting associated with a range of diseases and aging. Frailty in the aging population is a major socioeconomic and medical problem. Emerging molecular techniques have made it possible to gain a better understanding of the growth factor genes and how they are activated by physical activity. The ways that misuse of growth factors may be detected and verified in athletes and future challenges for detecting manipulation of signaling pathways are discussed. Copyright 2010. Published by Elsevier Inc.

Strain energy release rate analysis of cyclic delamination growth in compressively loaded laminates

NASA Technical Reports Server (NTRS)

Whitcomb, J. D.

1983-01-01

Delamination growth in compressively loaded composite laminates was studied analytically and experimentally. The configuration used was a laminate with an across-the-width delamination. An approximate super-position stress analysis was developed to quantify the effects of various geometric, material, and load parameters on mode 2 and mode 2 strain energy release rates G sub/1 and G sub 2, respectively. Calculated values of G sub 1 and G sub 2 were then compared with measured cyclic delamination growth rates to determine the relative importance of G sub 1 and G sub 2. High growth rates were observed only when G sub 1 was large. However, slow growth was observed even when G sub 1 was negligibly small. This growth apparently was due to a large value of G sub 2.

Early release improves long-term growth and development of direct-seeded nuttall oak saplings

Treesearch

James S. Meadows; Robert L. Johnson; Roger M. Krinard

2015-01-01

Early growth of bottomland oaks is typically slow, and many oaks eventually become overtopped by trees of other species. Removal of these larger competitors in a young stand might improve growth of the oaks and lead to more free-to-grow oaks as the stand matures. Release treatments were applied in 1980 to an 11-year-old, direct-seeded Nuttall oak (Quercus texana Buckl...

Growth factors and chronic wound healing: past, present, and future.

PubMed

Goldman, Robert

2004-01-01

Growth substances (cytokines and growth factors) are soluble signaling proteins affecting the process of normal wound healing. Cytokines govern the inflammatory phase that clears cellular and extracellular matrix debris. Wound repair is controlled by growth factors (platelet-derived growth factor [PDGF], keratinocyte growth factor, and transforming growth factor beta). Endogenous growth factors communicate across the dermal-epidermal interface. PDGF is important for most phases of wound healing. Becaplermin (PDGF-BB), the only growth factor approved by the Food and Drug Administration, requires daily application for neuropathic wound healing. Gene therapy is under development for more efficient growth factor delivery; a single application will induce constitutive growth factor expression for weeks. Based on dramatic preclinical animal studies, a phase 1 clinical trial planned on a PDGF genetic construct appears promising.

Predictive factors for intrauterine growth restriction

PubMed Central

Albu, AR; Anca, AF; Horhoianu, VV; Horhoianu, IA

2014-01-01

Abstract Reduced fetal growth is seen in about 10% of the pregnancies but only a minority has a pathological background and is known as intrauterine growth restriction or fetal growth restriction (IUGR / FGR). Increased fetal and neonatal mortality and morbidity as well as adult pathologic conditions are often associated to IUGR. Risk factors for IUGR are easy to assess but have poor predictive value. For the diagnostic purpose, biochemical serum markers, ultrasound and Doppler study of uterine and spiral arteries, placental volume and vascularization, first trimester growth pattern are object of assessment today. Modern evaluations propose combined algorithms using these strategies, all with the goal of a better prediction of risk pregnancies. Abbreviations: SGA = small for gestational age; IUGR = intrauterine growth restriction; FGR = fetal growth restriction; IUFD = intrauterine fetal demise; HIV = human immunodeficiency virus; PAPP-A = pregnancy associated plasmatic protein A; β-hCG = beta human chorionic gonadotropin; MoM = multiple of median; ADAM-12 = A-disintegrin and metalloprotease 12; PP-13 = placental protein 13; VEGF = vascular endothelial growth factor; PlGF = placental growth factor; sFlt-1 = soluble fms-like tyrosine kinase-1; UAD = uterine arteries Doppler ultrasound; RI = resistence index; PI = pulsatility index; VOCAL = Virtual Organ Computer–Aided Analysis software; VI = vascularization index; FI = flow index; VFI = vascularization flow index; PQ = placental quotient PMID:25408721

Growth factors delivery from hybrid PCL-starch scaffolds processed using supercritical fluid technology.

PubMed

Diaz-Gomez, Luis; Concheiro, Angel; Alvarez-Lorenzo, Carmen; García-González, Carlos A

2016-05-20

Synthetic polymeric scaffolds to be used as surrogates of autologous bone grafts should not only have suitable physicochemical and mechanical properties, but also contain bioactive agents such as growth factors (GFs) to facilitate the tissue growth. For this purpose, cost-effective and autologous GFs sources are preferred to avoid some post-surgery complications after implantation, like immunogenicity or disease transmission, and the scaffolds should be processed using methods able to preserve GFs activity. In this work, poly(ɛ-caprolactone) (PCL) scaffolds incorporating GFs were processed using a green foaming process based on supercritical fluid technology. Preparation rich in growth factors (PRGF), a natural and highly available cocktail of GFs obtained from platelet rich plasma (PRP), was used as GF source. PCL:starch:PRGF (85:10:5 weight ratio) porous solid scaffolds were obtained by a supercritical CO2-assisted foaming process at 100 bar and 37 °C with no need of post-processing steps. Bioactivity of GFs after processing and scaffold cytocompatibility were confirmed using mesenchymal stem cells. The performance of starch as GF control release component was shown to be dependent on starch pre-gelification conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Growth factors and growth factor receptors in the hippocampus. Role in plasticity and response to injury.

PubMed

Nieto-Sampedro, M; Bovolenta, P

1990-01-01

Various growth factors are present in the hippocampal formation and appear responsible for the prominent plasticity of this brain area. Although hormone-like growth-promoting polypeptides are the best known, recent studies emphasize the importance in the growth response of molecules such as laminin proteoglycans, neurotransmitters and growth inhibitors. The progress and problems in the study of these substances are reviewed.

Identification of candidate angiogenic inhibitors processed by matrix metalloproteinase 2 (MMP-2) in cell-based proteomic screens: disruption of vascular endothelial growth factor (VEGF)/heparin affin regulatory peptide (pleiotrophin) and VEGF/Connective tissue growth factor angiogenic inhibitory complexes by MMP-2 proteolysis.

PubMed

Dean, Richard A; Butler, Georgina S; Hamma-Kourbali, Yamina; Delbé, Jean; Brigstock, David R; Courty, José; Overall, Christopher M

2007-12-01

Matrix metalloproteinases (MMPs) exert both pro- and antiangiogenic functions by the release of cytokines or proteolytically generated angiogenic inhibitors from extracellular matrix and basement membrane remodeling. In the Mmp2-/- mouse neovascularization is greatly reduced, but the mechanistic aspects of this remain unclear. Using isotope-coded affinity tag labeling of proteins analyzed by multidimensional liquid chromatography and tandem mass spectrometry we explored proteome differences between Mmp2-/- cells and those rescued by MMP-2 transfection. Proteome signatures that are hallmarks of proteolysis revealed cleavage of many known MMP-2 substrates in the cellular context. Proteomic evidence of MMP-2 processing of novel substrates was found. Insulin-like growth factor binding protein 6, follistatin-like 1, and cystatin C protein cleavage by MMP-2 was biochemically confirmed, and the cleavage sites in heparin affin regulatory peptide (HARP; pleiotrophin) and connective tissue growth factor (CTGF) were sequenced by matrix-assisted laser desorption ionization-time of flight mass spectrometry. MMP-2 processing of HARP and CTGF released vascular endothelial growth factor (VEGF) from angiogenic inhibitory complexes. The cleaved HARP N-terminal domain increased HARP-induced cell proliferation, whereas the HARP C-terminal domain was antagonistic and decreased cell proliferation and migration. Hence the unmasking of cytokines, such as VEGF, by metalloproteinase processing of their binding proteins is a new mechanism in the control of cytokine activation and angiogenesis.

Identification of Candidate Angiogenic Inhibitors Processed by Matrix Metalloproteinase 2 (MMP-2) in Cell-Based Proteomic Screens: Disruption of Vascular Endothelial Growth Factor (VEGF)/Heparin Affin Regulatory Peptide (Pleiotrophin) and VEGF/Connective Tissue Growth Factor Angiogenic Inhibitory Complexes by MMP-2 Proteolysis▿ †

PubMed Central

Dean, Richard A.; Butler, Georgina S.; Hamma-Kourbali, Yamina; Delbé, Jean; Brigstock, David R.; Courty, José; Overall, Christopher M.

2007-01-01

Matrix metalloproteinases (MMPs) exert both pro- and antiangiogenic functions by the release of cytokines or proteolytically generated angiogenic inhibitors from extracellular matrix and basement membrane remodeling. In the Mmp2−/− mouse neovascularization is greatly reduced, but the mechanistic aspects of this remain unclear. Using isotope-coded affinity tag labeling of proteins analyzed by multidimensional liquid chromatography and tandem mass spectrometry we explored proteome differences between Mmp2−/− cells and those rescued by MMP-2 transfection. Proteome signatures that are hallmarks of proteolysis revealed cleavage of many known MMP-2 substrates in the cellular context. Proteomic evidence of MMP-2 processing of novel substrates was found. Insulin-like growth factor binding protein 6, follistatin-like 1, and cystatin C protein cleavage by MMP-2 was biochemically confirmed, and the cleavage sites in heparin affin regulatory peptide (HARP; pleiotrophin) and connective tissue growth factor (CTGF) were sequenced by matrix-assisted laser desorption ionization-time of flight mass spectrometry. MMP-2 processing of HARP and CTGF released vascular endothelial growth factor (VEGF) from angiogenic inhibitory complexes. The cleaved HARP N-terminal domain increased HARP-induced cell proliferation, whereas the HARP C-terminal domain was antagonistic and decreased cell proliferation and migration. Hence the unmasking of cytokines, such as VEGF, by metalloproteinase processing of their binding proteins is a new mechanism in the control of cytokine activation and angiogenesis. PMID:17908800

Engineering growth factors for regenerative medicine applications.

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

Mitchell, Aaron C.; Briquez, Priscilla S.; Hubbell, Jeffrey A.

Growth factors are important morphogenetic proteins that instruct cell behavior and guide tissue repair and renewal. Although their therapeutic potential holds great promise in regenerative medicine applications, translation of growth factors into clinical treatments has been hindered by limitations including poor protein stability, low recombinant expression yield, and suboptimal efficacy. This review highlights current tools, technologies, and approaches to design integrated and effective growth factor-based therapies for regenerative medicine applications. The first section describes rational and combinatorial protein engineering approaches that have been utilized to improve growth factor stability, expression yield, biodistribution, and serum half-life, or alter their cell traffickingmore » behavior or receptor binding affinity. The second section highlights elegant biomaterial-based systems, inspired by the natural extracellular matrix milieu, that have been developed for effective spatial and temporal delivery of growth factors to cell surface receptors. Although appearing distinct, these two approaches are highly complementary and involve principles of molecular design and engineering to be considered in parallel when developing optimal materials for clinical applications.« less

Glucose impairs tamoxifen responsiveness modulating connective tissue growth factor in breast cancer cells.

PubMed

Ambrosio, Maria Rosaria; D'Esposito, Vittoria; Costa, Valerio; Liguoro, Domenico; Collina, Francesca; Cantile, Monica; Prevete, Nella; Passaro, Carmela; Mosca, Giusy; De Laurentiis, Michelino; Di Bonito, Maurizio; Botti, Gerardo; Franco, Renato; Beguinot, Francesco; Ciccodicola, Alfredo; Formisano, Pietro

2017-12-12

Type 2 diabetes and obesity are negative prognostic factors in patients with breast cancer (BC). We found that sensitivity to tamoxifen was reduced by 2-fold by 25 mM glucose (High Glucose; HG) compared to 5.5 mM glucose (Low Glucose; LG) in MCF7 BC cells. Shifting from HG to LG ameliorated MCF7 cell responsiveness to tamoxifen. RNA-Sequencing of MCF7 BC cells revealed that cell cycle-related genes were mainly affected by glucose. Connective Tissue Growth Factor (CTGF) was identified as a glucose-induced modulator of cell sensitivity to tamoxifen. Co-culturing MCF7 cells with human adipocytes exposed to HG, enhanced CTGF mRNA levels and reduced tamoxifen responsiveness of BC cells. Inhibition of adipocyte-released IL8 reverted these effects. Interestingly, CTGF immuno-detection in bioptic specimens from women with estrogen receptor positive (ER + ) BC correlated with hormone therapy resistance, distant metastases, reduced overall and disease-free survival. Thus, glucose affects tamoxifen responsiveness directly modulating CTGF in BC cells, and indirectly promoting IL8 release by adipocytes.

Effects of heparin-binding epidermal growth factor-like growth factor on cell repopulation and signal transduction in periodontal ligament cells after scratch wounding in vitro.

PubMed

Lee, J S; Kim, J M; Hong, E K; Kim, S-O; Yoo, Y-J; Cha, J-H

2009-02-01

A growing amount of attention has been placed on periodontal regeneration and wound healing for periodontal therapy. This study was conducted in an effort to determine the effects of heparin-binding epidermal growth factor-like growth factor on cell repopulation and signal transduction in periodontal ligament cells after scratch wounding in vitro. Human periodontal ligament cells were acquired from explant tissue of human healthy periodontal ligament. After the wounding of periodontal ligament cells, the change in expression of heparin-binding epidermal growth factor-like growth factor and epidermal growth factor receptors 1-4 mRNA was assessed. The effects of heparin-binding epidermal growth factor-like growth factor on periodontal ligament cell proliferation and repopulation were assessed in vitro via the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and by photographing the injuries, respectively. Extracellular signal-regulated kinase (Erk)1/2, p38 and Akt phosphorylation was characterized via western blotting. Scratch wounding resulted in a significant up-regulation of heparin-binding epidermal growth factor-like growth factor mRNA expression, whereas wounding had no effect on the expression levels of epidermal growth factor receptors 1-4. Interestingly, no expression of epidermal growth factor receptors 2 and 4 was detectable prior to or after wounding. Heparin-binding epidermal growth factor-like growth factor treatment promoted the proliferation and repopulation of periodontal ligament cells. The scratch wounding also stimulated the phosphorylation of Erk1/2 and p38, but not of Akt, in periodontal ligament cells, and heparin-binding epidermal growth factor-like growth factor treatment applied after wounding amplified and extended the activations of Erk1/2 and p38, but not of Akt. Furthermore, Erk1/2 inhibition blocked the process of cell repopulation induced by heparin-binding epidermal growth factor-like growth factor, whereas the

Growth factor involvement in tension-induced skeletal muscle growth

NASA Technical Reports Server (NTRS)

Vandenburgh, H. H.

1987-01-01

Muscle tissue culture techniques were developed to grow skeletal myofibers which differentiate into more adult-like myofibers. Mechanical simulation studies of these muscle cells in a newly developed mechanical cell simulator can now be performed to study growth processes in skeletal muscle. Conditions in the mechanical cell simulator were defined where mechanical activity can either prevent muscle wasting or stimulate muscle growth. The role of endogenous and exogenous growth factors in tension-induced muscle growth is being investigated under the defined conditions of tissue culture.

Fibroblast growth factor receptor inhibitors.

PubMed

Kumar, Suneel B V S; Narasu, Lakshmi; Gundla, Rambabu; Dayam, Raveendra; J A R P, Sarma

2013-01-01

Fibroblast growth factor receptors (FGFRs) play an important role in embryonic development, angiogenesis, wound healing, cell proliferation and differentiation. The fibroblast growth factor receptor (FGFR) isoforms have been under intense scrutiny for effective anticancer drug candidates. The fibroblast growth factor (FGF) and its receptor (FGFR) provide another pathway that seems critical to monitoring angiogenesis. Recent findings suggest that FGFR mediates signaling, regulates the PKM2 activity, and plays a crucial role in cancer metabolism. The current review also covers the recent findings on the role of FGFR1 in cancer metabolism. This paper reviews the progress, mechanism, and binding modes of recently known kinase inhibitors such as PD173074, SU series and other inhibitors still under clinical development. Some of the structural classes that will be highlighted in this review include Pyrido[2,3-d]pyrimidines, Indolin- 2-one, Pyrrolo[2,1-f][1,2,4]triazine, Pyrido[2,3-d]pyrimidin-7(8H)-one, and 1,6- Naphthyridin-2(1H)-ones.

Fibroblast Growth Factor Signaling Mediates Pulmonary Endothelial Glycocalyx Reconstitution

PubMed Central

Yang, Yimu; Haeger, Sarah M.; Suflita, Matthew A.; Zhang, Fuming; Dailey, Kyrie L.; Colbert, James F.; Ford, Joshay A.; Picon, Mario A.; Stearman, Robert S.; Lin, Lei; Liu, Xinyue; Han, Xiaorui; Linhardt, Robert J.

2017-01-01

The endothelial glycocalyx is a heparan sulfate (HS)–rich endovascular structure critical to endothelial function. Accordingly, endothelial glycocalyx degradation during sepsis contributes to tissue edema and organ injury. We determined the endogenous mechanisms governing pulmonary endothelial glycocalyx reconstitution, and if these reparative mechanisms are impaired during sepsis. We performed intravital microscopy of wild-type and transgenic mice to determine the rapidity of pulmonary endothelial glycocalyx reconstitution after nonseptic (heparinase-III mediated) or septic (cecal ligation and puncture mediated) endothelial glycocalyx degradation. We used mass spectrometry, surface plasmon resonance, and in vitro studies of human and mouse samples to determine the structure of HS fragments released during glycocalyx degradation and their impact on fibroblast growth factor receptor (FGFR) 1 signaling, a mediator of endothelial repair. Homeostatic pulmonary endothelial glycocalyx reconstitution occurred rapidly after nonseptic degradation and was associated with induction of the HS biosynthetic enzyme, exostosin (EXT)-1. In contrast, sepsis was characterized by loss of pulmonary EXT1 expression and delayed glycocalyx reconstitution. Rapid glycocalyx recovery after nonseptic degradation was dependent upon induction of FGFR1 expression and was augmented by FGF-promoting effects of circulating HS fragments released during glycocalyx degradation. Although sepsis-released HS fragments maintained this ability to activate FGFR1, sepsis was associated with the downstream absence of reparative pulmonary endothelial FGFR1 induction. Sepsis may cause vascular injury not only via glycocalyx degradation, but also by impairing FGFR1/EXT1–mediated glycocalyx reconstitution. PMID:28187268

Emerging vascular endothelial growth factor antagonists to treat neovascular age-related macular degeneration.

PubMed

Hussain, Rehan M; Ciulla, Thomas A

2017-09-01

Evolving anti-vascular endothelial growth factor (VEGF) treatments for neovascular age-related macular degeneration (nAMD) include long acting agents, combination strategies involving new pathways, topical agents, sustained-release, and genetic therapy strategies. Areas covered: Brolucizumab and abicipar pegol have smaller molecular size, facilitating higher concentrations and potentially longer duration than current anti-VEGF agents. Agents being combined with anti-VEGFs include OPT-302 (to inhibit VEGF-C and VEGF-D); pegpleranib and rinucumab (to inhibit platelet derived growth factor, PDGF - but both failed to show consistently improved visual outcomes compared to anti-VEGF monotherapy); and RG7716, ARP-1536 and nesvacumab (to activate the Tie-2 tyrosine kinase receptor, which reduces permeability). X-82 is an oral anti-VEGF and anti-PDGF being tested in phase 2 studies. Topical anti-VEGF ± anti-PDGF drugs under study include pazopanib, PAN-90806, squalamine lactate, regorafinib, and LHA510. Sustained-release anti-VEGF delivery treatments, such as the ranibizumab Port Delivery System, GB-102, NT-503, hydrogel depot, Durasert, and ENV1305 aim to reduce the burden of frequent injections. Gene therapies with new viral vectors hold the potential to induce sustained expression of anti-angiogenic proteins via the retina's cellular apparatus, and include AVA-101/201, ADVM-202/302, AAV2-sFLT01, RGX314, and Retinostat. Expert opinion: There are many emerging anti-VEGF treatments that aim to improve visual outcomes and reduce the treatment burden of nAMD.

Expression of a transmembrane phosphotyrosine phosphatase inhibits cellular response to platelet-derived growth factor and insulin-like growth factor-1.

PubMed

Mooney, R A; Freund, G G; Way, B A; Bordwell, K L

1992-11-25

Tyrosine phosphorylation is a mechanism of signal transduction shared by many growth factor receptors and oncogene products. Phosphotyrosine phosphatases (PTPases) potentially modulate or counter-regulate these signaling pathways. To test this hypothesis, the transmembrane PTPase CD45 (leukocyte common antigen) was expressed in the murine cell line C127. Hormone-dependent autophosphorylation of the platelet-derived growth factor (PDGF) and insulin-like growth factor-1 (IGF-1) receptors was markedly reduced in cells expressing the transmembrane PTPase. Tyrosine phosphorylation of other PDGF-dependent phosphoproteins (160, 140, and 55 kDa) and IGF-1-dependent phosphoproteins (145 kDa) was similarly decreased. Interestingly, the pattern of growth factor-independent tyrosine phosphorylations was comparable in cells expressing the PTPase and control cells. This suggests a selectivity or accessibility of the PTPase limited to a subset of cellular phosphotyrosyl proteins. The maximum mitogenic response to PDGF and IGF-1 in cells expressing the PTPase was decreased by 67 and 71%, respectively. These results demonstrate that a transmembrane PTPase can both affect the tyrosine phosphorylation state of growth factor receptors and modulate proximal and distal cellular responses to the growth factors.

Cross-talk between GPER and growth factor signaling.

PubMed

Lappano, Rosamaria; De Marco, Paola; De Francesco, Ernestina Marianna; Chimento, Adele; Pezzi, Vincenzo; Maggiolini, Marcello

2013-09-01

G protein-coupled receptors (GPCRs) and growth factor receptors mediate multiple physio-pathological responses to a diverse array of extracellular stimuli. In this regard, it has been largely demonstrated that GPCRs and growth factor receptors generate a multifaceted signaling network, which triggers relevant biological effects in normal and cancer cells. For instance, some GPCRs transactivate the epidermal growth factor receptor (EGFR), which stimulates diverse transduction pathways leading to gene expression changes, cell migration, survival and proliferation. Moreover, it has been reported that a functional interaction between growth factor receptors and steroid hormones like estrogens is involved in the growth of many types of tumors as well as in the resistance to endocrine therapy. This review highlights recent findings on the cross-talk between a member of the GPCR family, the G protein-coupled estrogen receptor 1 (GPER, formerly known as GPR30) and two main growth factor receptors like EGFR and insulin-like growth factor-I receptor (IGF-IR). The biological implications of the functional interaction between these important mediators of cell responses particularly in cancer are discussed. This article is part of a Special Issue entitled 'CSR 2013'. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effective Delivery of Doxycycline and Epidermal Growth Factor for Expedited Healing of Chronic Wounds

NASA Astrophysics Data System (ADS)

Kulkarni, Abhilash

The problems and high medical costs associated with chronic wounds necessitate an economical bioactive wound dressing. A new strategy was investigated to inhibit MMP-9 proteases and to release epidermal growth factor (EGF) to enhance healing. Doxycycline (DOX) and EGF were encapsulated on polyacrylic acid modified polyurethane film (PAA-PU) using Layer-by-Layer (LbL) assembly. The number of bilayers tuned the concentration of DOX and EGF released over time with over 94% bioactivity of EGF retained over 4 days. A simple wound model in which MMP-9 proteases were added to cell culture containing fibroblast cells demonstrated that DOX inhibited the proteases providing a protective environment for the released EGF to stimulate cell migration and proliferation at a faster healing rate. In the presence of DOX, only small amounts of the highly bioactive EGF are sufficient to close the wound. Results show that this is new and promising bioactive dressing for effective wound management.

Time dependent impact of perinatal hypoxia on growth hormone, insulin-like growth factor 1 and insulin-like growth factor binding protein-3.

PubMed

Kartal, Ömer; Aydınöz, Seçil; Kartal, Ayşe Tuğba; Kelestemur, Taha; Caglayan, Ahmet Burak; Beker, Mustafa Caglar; Karademir, Ferhan; Süleymanoğlu, Selami; Kul, Mustafa; Yulug, Burak; Kilic, Ertugrul

2016-08-01

Hypoxic-ischemia (HI) is a widely used animal model to mimic the preterm or perinatal sublethal hypoxia, including hypoxic-ischemic encephalopathy. It causes diffuse neurodegeneration in the brain and results in mental retardation, hyperactivity, cerebral palsy, epilepsy and neuroendocrine disturbances. Herein, we examined acute and subacute correlations between neuronal degeneration and serum growth factor changes, including growth hormone (GH), insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) after hypoxic-ischemia (HI) in neonatal rats. In the acute phase of hypoxia, brain volume was increased significantly as compared with control animals, which was associated with reduced GH and IGF-1 secretions. Reduced neuronal survival and increased DNA fragmentation were also noticed in these animals. However, in the subacute phase of hypoxia, neuronal survival and brain volume were significantly decreased, accompanied by increased apoptotic cell death in the hippocampus and cortex. Serum GH, IGF-1, and IGFBP-3 levels were significantly reduced in the subacute phase of HI. Significant retardation in the brain and body development were noted in the subacute phase of hypoxia. Here, we provide evidence that serum levels of growth-hormone and factors were decreased in the acute and subacute phase of hypoxia, which was associated with increased DNA fragmentation and decreased neuronal survival.

Role of G protein-coupled receptors (GPCR), matrix metalloproteinases 2 and 9 (MMP2 and MMP9), heparin-binding epidermal growth factor-like growth factor (hbEGF), epidermal growth factor receptor (EGFR), erbB2, and insulin-like growth factor 1 receptor (IGF-1R) in trenbolone acetate-stimulated bovine satellite cell proliferation.

PubMed

Thornton, K J; Kamange-Sollo, E; White, M E; Dayton, W R

2015-09-01

Implanting cattle with steroids significantly enhances feed efficiency, rate of gain, and muscle growth. However, the mechanisms responsible for these improvements in muscle growth have not been fully elucidated. Trenbolone acetate (TBA), a testosterone analog, has been shown to increase proliferation rate in bovine satellite cell (BSC) cultures. The classical genomic actions of testosterone have been well characterized; however, our results indicate that TBA may also initiate a quicker, nongenomic response that involves activation of G protein-coupled receptors (GPCR) resulting in activation of matrix metalloproteinases 2 and 9 (MMP2 and MMP9) that release membrane-bound heparin-binding epidermal growth factor-like growth factor (hbEGF), which then binds to and activates the epidermal growth factor receptor (EGFR) and/or erbB2. Furthermore, the EGFR has been shown to regulate expression of the IGF-1 receptor (IGF-1R), which is well known for its role in modulating muscle growth. To determine whether this nongenomic pathway is potentially involved in TBA-stimulated BSC proliferation, we analyzed the effects of treating BSC with guanosine 5'-O-2-thiodiphosphate (GDPβS), an inhibitor of all GPCR; a MMP2 and MMP9 inhibitor (MMPI); CRM19, a specific inhibitor of hbEGF; AG1478, a specific EGFR tyrosine kinase inhibitor; AG879, a specific erbB2 kinase inhibitor; and AG1024, an IGF-1R tyrosine kinase inhibitor on TBA-stimulated proliferation rate (H-thymidine incorporation). Assays were replicated at least 9 times for each inhibitor experiment using BSC cultures obtained from at least 3 different animals. Bovine satellite cell cultures were obtained from yearling steers that had no previous exposure to androgenic or estrogenic compounds. As expected, BSC cultures treated with 10 n TBA showed ( < 0.05) increased proliferation rate when compared with control cultures. Additionally, treatment with 5 ng hbEGF/mL stimulated proliferation in BSC cultures ( < 0.05). Treatment

Heparin/collagen encapsulating nerve growth factor multilayers coated aligned PLLA nanofibrous scaffolds for nerve tissue engineering.

PubMed

Zhang, Kuihua; Huang, Dianwu; Yan, Zhiyong; Wang, Chunyang

2017-07-01

Biomimicing topological structure of natural nerve tissue to direct axon growth and controlling sustained release of moderate neurotrophic factors are extremely propitious to the functional recovery of damaged nervous systems. In this study, the heparin/collagen encapsulating nerve growth factor (NGF) multilayers were coated onto the aligned poly-L-lactide (PLLA) nanofibrous scaffolds via a layer-by-layer (LbL) self-assembly technique to combine biomolecular signals, and physical guidance cues for peripheral nerve regeneration. Scanning electronic microscopy (SEM) revealed that the surface of aligned PLLA nanofibrous scaffolds coated with heparin/collagen multilayers became rougher and appeared some net-like filaments and protuberances in comparison with PLLA nanofibrous scaffolds. The heparin/collagen multilayers did not destroy the alignment of nanofibers. X-ray photoelectron spectroscopy and water contact angles displayed that heparin and collagen were successfully coated onto the aligned PLLA nanofibrous scaffolds and improved its hydrophilicity. Three-dimensional (3 D) confocal microscopy images further demonstrated that collagen, heparin, and NGF were not only coated onto the surface of aligned PLLA nanofibrous scaffolds but also permeated into the inner of scaffolds. Moreover, NGF presented a sustained release for 2 weeks from aligned nanofibrous scaffolds coated with 5.5 bilayers or above and remained good bioactivity. The heparin/collagen encapsulating NGF multilayers coated aligned nanofibrous scaffolds, in particular 5.5 bilayers or above, was more beneficial to Schwann cells (SCs) proliferation and PC12 cells differentiation as well as the SC cytoskeleton and neurite growth along the direction of nanofibrous alignment compared to the aligned PLLA nanofibrous scaffolds. This novel scaffolds combining sustained release of bioactive NGF and aligned nanofibrous topography presented an excellent potential in peripheral nerve regeneration. © 2016 Wiley

Impairment of Host Liver Repopulation by Transplanted Hepatocytes in Aged Rats and the Release by Short-Term Growth Hormone Treatment.

PubMed

Stock, Peggy; Bielohuby, Maximilian; Staege, Martin S; Hsu, Mei-Ju; Bidlingmaier, Martin; Christ, Bruno

2017-03-01

Hepatocyte transplantation is an alternative to whole liver transplantation. Yet, efficient liver repopulation by transplanted hepatocytes is low in livers of old animals. This restraint might be because of the poor proliferative capacity of aged donor hepatocytes or the regenerative impairment of the recipient livers. The age-dependent liver repopulation by transplanted wild-type hepatocytes was investigated in juvenile and senescent rats deficient in dipeptidyl-peptidase IV. Repopulation was quantified by flow cytometry and histochemical estimation of dipeptidyl-peptidase IV enzyme activity of donor cells in the negative host liver. As a potential pathway involved, expression of cell cycle proteins was assessed. Irrespective of the age of the donor hepatocytes, large cell clusters appeared in juvenile, but only small clusters in senescent host livers. Because juvenile and senescent donor hepatocytes were likewise functional, host-derived factor(s) impaired senescent host liver repopulation. Growth hormone levels were significantly higher in juvenile than in senescent rats, suggesting that growth hormone might promote host liver repopulation. Indeed, short-term treatment with growth hormone augmented senescent host liver repopulation involving the growth hormone-mediated release of the transcriptional blockade of genes associated with cell cycle progression. Short-term growth hormone substitution might improve liver repopulation by transplanted hepatocytes, thus augmenting the therapeutic benefit of clinical hepatocyte transplantation in older patients. Copyright © 2017 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Morphogen and proinflammatory cytokine release kinetics from PRGF-Endoret fibrin scaffolds: evaluation of the effect of leukocyte inclusion.

PubMed

Anitua, E; Zalduendo, M M; Prado, R; Alkhraisat, M H; Orive, G

2015-03-01

The potential influence of leukocyte incorporation in the kinetic release of growth factors from platelet-rich plasma (PRP) may explain the conflicting efficiency of leukocyte platelet-rich plasma (L-PRP) scaffolds in tissue regeneration. To assess this hypothesis, leukocyte-free (PRGF-Endoret) and L-PRP fibrin scaffolds were prepared, and both morphogen and proinflammatory cytokine release kinetics were analyzed. Clots were incubated with culture medium to monitor protein release over 8 days. Furthermore, the different fibrin scaffolds were morphologically characterized. Results show that leukocyte-free fibrin matrices were homogenous while leukocyte-containing ones were heterogeneous, loose and cellular. Leukocyte incorporation produced a significant increase in the contents of proinflammatory cytokines interleukin (IL)-1β and IL-16 but not in the platelet-derived growth factors release (<1.5-fold). Surprisingly, the availability of vascular endothelial growth factor suffered an important decrease after 3 days of incubation in the case of L-PRP matrices. While the release of proinflammatory cytokines was almost absent or very low from PRGF-Endoret, the inclusion of leukocytes induced a major increase in these cytokines, which was characterized by the presence of a latent period. The PRGF-Endoret matrices were stable during the 8 days of incubation. The inclusion of leukocytes alters the growth factors release profile and also increased the dose of proinflammatory cytokines. © 2014 Wiley Periodicals, Inc.

Effects of long-term treatment with growth hormone-releasing peptide-2 in the GHRH knockout mouse.

PubMed

Alba, Maria; Fintini, Danilo; Bowers, Cyril Y; Parlow, A F; Salvatori, Roberto

2005-11-01

Growth hormone (GH) secretagogues (GHS) stimulate GH secretion in vivo in humans and in animals. They act on the ghrelin receptor, expressed in both the hypothalamus and the pituitary. It is unknown whether GHSs act predominantly by increasing the release of hypothalamic GH-releasing hormone (GHRH) or by acting directly on the somatotroph cells. We studied whether a potent GHS could stimulate growth in the absence of endogenous GHRH. To this end, we used GHRH knockout (GHRH-KO) mice. These animals have proportionate dwarfism due to severe GH deficiency (GHD) and pituitary hypoplasia due to reduced somatotroph cell mass. We treated male GHRH-KO mice for 6 wk (from week 1 to week 7 of age) with GH-releasing peptide-2 (GHRP-2, 10 microg s.c. twice a day). Chronic treatment with GHRP-2 failed to stimulate somatotroph cell proliferation and GH secretion and to promote longitudinal growth. GHRP-2-treated mice showed an increase in total body weight compared with placebo-treated animals, due to worsening of the body composition alterations typical of GHD animals. These data demonstrate that GHRP-2 failed to reverse the severe GHD caused by lack of GHRH.

Effect of combined locally delivered growth factors and systemic sildenafil citrate on microrecanalization in biodegradable conduit for vas deferens reconstruction.

PubMed

Rosevear, Henry M; Krishnamachari, Yogita; Ariza, Carlos A; Mallapragada, Surya K; Salem, Aliasger K; Griffith, Thomas S; De Young, Barry R; Wald, Moshe

2012-04-01

To investigate the effect of the combination of locally delivered growth factors and oral sildenafil citrate on cross-conduit microrecanalization. A total of 42 rats were divided into 7 groups. Of the 42 rats, 6 underwent bilateral vasectomy and bilateral end-to-end vasovasostomy and 12 underwent bilateral vasectomy. Of the latter 12, 6 received sildenafil citrate orally (10 mg/kg/d) for 24 weeks and 6 received placebo. A total of 24 rats underwent bilateral vasectomy and bilateral reconstruction with implantation of a 5-mm biodegradable conduit that bridged the 2 vasal ends. Of the 24 rats with conduits, 12 also had 250 pg of transforming growth factor-β and 12.5 pg of platelet-derived growth factor-β sustained release nanoparticles placed in immediate proximity to the conduit. The remaining 12 rats with conduits (6 without growth factors and 6 with growth factors) also received sildenafil citrate orally (10 mg/kg/d) for 24 weeks; the others received placebo. The reconstructed segments were harvested for histologic examination at 24 weeks. Five of 6 primary vasovasostomy and no vasectomy-only rats sired litters. Significantly more microcanals per conduit were observed in rats receiving sildenafil citrate: without growth factors, 3.9 vs. 0 canals/conduit (P < 0.001); with growth factors, 5.5 vs. 0.25 canals/conduit (P < 0.001). The rats receiving sildenafil citrate with growth factors showed a trend toward more microcanals per conduit than the rats receiving sildenafil citrate without growth factors (5.5 vs 3.9; P = .10). Rats receiving growth factors but no sildenafil citrate did not produce more canals than the rats receiving neither growth factor nor sildenafil citrate (0.25 vs 0; P = NS). Orally administered sildenafil citrate enhances formation of microcanalization after postvasectomy reconstruction using a biodegradable conduit in a rat model. Locally delivered growth factors appear to increase the number of microcanals. Copyright © 2012 Elsevier Inc. All

Kisspeptin stimulates growth hormone release by utilizing Neuropeptide Y pathways and is dependent on the presence of ghrelin

USDA-ARS?s Scientific Manuscript database

Although kisspeptin is the primary stimulator of gonadotropin releasing hormone secretion and therefore the hypothalamic-pituitary gonadal axis, new findings suggest kisspeptin can also regulate additional neuroendocrine processes including release of growth hormone (GH). Central delivery of kisspep...

Role of growth hormone, insulin-like growth factor-I, and insulin-like growth factor binding proteins in the catabolic response to injury and infection.

PubMed

Lang, Charles H; Frost, Robert A

2002-05-01

The erosion of lean body mass resulting from protracted critical illness remains a significant risk factor for increased morbidity and mortality in this patient population. Previous studies have documented the well known impairment in nitrogen balance results from both an increase in muscle protein degradation as well as a decreased rate of both myofibrillar and sacroplasmic protein synthesis. This protein imbalance may be caused by an increased presence or activity of various catabolic agents, such as tumor necrosis factor-alpha, interleukin-1 beta, interleukin-6 or glucocorticoids, or may be mediated via a decreased concentration or responsiveness to various anabolic hormones, such as growth hormone or insulin-like growth factor-I. This review focuses on recent developments pertaining to the importance of alterations in the growth hormone-insulin-like growth factor-I axis as a mechanism for the observed defects in muscle protein balance.

Constructing a blood vessel on the porous scaffold modified with vascular endothelial growth factor and basic fibroblast growth factor

NASA Astrophysics Data System (ADS)

Sevostyanova, V. V.; Matveeva, V. G.; Antonova, L. V.; Velikanova, E. A.; Shabaev, A. R.; Senokosova, E. A.; Krivkina, E. O.; Vasyukov, G. Yu.; Glushkova, T. V.; Kudryavtseva, Yu. A.; Barbarash, O. L.; Barbarash, L. S.

2016-11-01

Incorporation of the growth factors into biodegradable polymers is a promising approach for the fabrication of tissue-engineered vascular grafts. Here we blended poly(ɛ-caprolactone) (PCL) with poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) following incorporation of either vascular endothelial growth factor (VEGF) or basic fibroblast growth factor (bFGF) and then fabricated electrospun 2 mm diameter vascular grafts. Grafts without the growth factors were used as a control group. Structure of the grafts was assessed utilizing scanning electron microscopy. We further implanted our grafts into rat abdominal aorta for 1 and 3 months with the aim to test endothelialization, cell infiltration, and patency in vivo. Histological and immunofluorescence examination demonstrated enhanced endothelialization and cell infiltration of the grafts with either VEGF or bFGF compared to those without the growth factors. Grafts with VEGF showed higher patency compared to those with bFGF; however, bFGF promoted migration of smooth muscle cells and fibroblasts into the graft. Therefore, we conclude that incorporation of VEGF and bFGF into the inner and medial/outer layer, respectively, can be a promising option for the fabrication of tissue-engineered vascular grafts.

Inhibition by somatostatin (growth-hormone release-inhibiting hormone, GH-RIH) of gastric acid and pepsin and G-cell release of gastrin.

PubMed Central

Barros D'sa, A A; Bloom, S R; Baron, J H

1978-01-01

Somatostatin (cyclic growth-hormone release-inhibiting hormone--GH-RIH) was infused into dogs with gastric fistulae. Somatostatin inhibited gastric acid response to four gastric stimulants--insulin, food, histamine, and pentagastrin. Histamine- and pentagastrin-stimulated pepsins were inhibited similarly to inhibition of acid. Somatostatin inhibited the gastrin response to insulin and food. PMID:348581

Growth of suppressed grand fir and Shasta red fir in central Oregon after release and thinning—10-year results.

Treesearch

Kenneth W. Seidel

1983-01-01

A 43-year-old, even-aged stand of advance reproduction of grand fir and Shasta red fir in central Oregon responded to release and thinning with diameter and height growth two to three times the prerelease rate. The response began immediately after the overstory was killed with 2,4-D. Diameter growth during the second 5 years after release increased significantly over...

TERATOGENIC RESPONSES ARE MODULATED IN MICE LACKING EXPRESSION OF EPIDERMAL GROWTH FACTOR (EGF) AND TRANSFORMING GROWTH FACTOR-ALPHA (TGF)

EPA Science Inventory

TITLE:
TERATOGENIC RESPONSES ARE MODULATED IN MICE LACKING EXPRESSION OF EPIDERMAL GROWTH FACTOR (EGF) AND TRANSFORMING GROWTH FACTOR-ALPHA (TGF). AUTHORS (ALL): Abbott, Barbara D.1; Best, Deborah S.1; Narotsky, Michael G.1. SPONSOR NAME: None INSTITUTIONS (ALL): 1. Repro Tox ...

Controlled release of TGF-beta 1 from RADA self-assembling peptide hydrogel scaffolds

PubMed Central

Zhou, Ao; Chen, Shuo; He, Bin; Zhao, Weikang; Chen, Xiaojun; Jiang, Dianming

2016-01-01

Bioactive mediators, cytokines, and chemokines have an important role in regulating and optimizing the synergistic action of materials, cells, and cellular microenvironments for tissue engineering. RADA self-assembling peptide hydrogels have been proved to have an excellent ability to promote cell proliferation, wound healing, tissue repair, and drug delivery. Here, we report that D-RADA16 and L-RADA16-RGD self-assembling peptides can form stable second structure and hydrogel scaffolds, affording the slow release of growth factor (transforming growth factor cytokine-beta 1 [TGF-beta 1]). In vitro tests demonstrated that the plateau release amount can be obtained till 72 hours. Moreover, L-RADA16, D-RADA16, and L-RADA16-RGD self-assembling peptide hydrogels containing TGF-beta 1 were used for 3D cell culture of bone mesenchymal stem cells of rats for 2 weeks. The results revealed that these three RADA16 peptide hydrogels had a significantly favorable influence on proliferation of bone mesenchymal stem cells and hold some promise in slow and sustained release of growth factor. PMID:27703332

Delivery of growth factors for tissue regeneration and wound healing.

PubMed

Koria, Piyush

2012-06-01

Growth factors are soluble secreted proteins capable of affecting a variety of cellular processes important for tissue regeneration. Consequently, the self-healing capacity of patients can be augmented by artificially enhancing one or more processes important for healing through the application of growth factors. However, their application in clinics remains limited due to lack of robust delivery systems and biomaterial carriers. Interestingly, all clinically approved therapies involving growth factors utilize some sort of a biomaterial carrier for growth factor delivery. This suggests that biomaterial delivery systems are extremely important for successful usage of growth factors in regenerative medicine. This review outlines the role of growth factors in tissue regeneration, and their application in both pre-clinical animal models of regeneration and clinical trials is discussed. Additionally, current status of biomaterial substrates and sophisticated delivery systems such as nanoparticles for delivery of exogenous growth factors and peptides in humans are reviewed. Finally, issues and possible future research directions for growth factor therapy in regenerative medicine are discussed.

Physiological role of somatostatin-mediated autofeedback regulation for growth hormone: importance of growth hormone in triggering somatostatin release during a trough period of pulsatile growth hormone release in conscious male rats.

PubMed

Sato, M; Chihara, K; Kita, T; Kashio, Y; Okimura, Y; Kitajima, N; Fujita, T

1989-08-01

In mammals including human, it is generally accepted that growth hormone (GH) can regulate its own secretion through an autofeedback mechanism in which somatostatin (SRIF) may be involved. To explore a physiological role of SRIF-mediated GH autoregulation, the effect of exogenous human GH administration on plasma rat GH response to [D-Ala2, Nle27]-human GH-releasing hormone-(1-28)-agmatine (hGHRH-analog), which does not crossreact with anti-rat GH-releasing hormone gamma-globulin (GHRH-Ab), was examined in conscious male rats treated with GHRH-Ab in the absence and presence of anti-SRIF gamma-globulin (SRIF-Ab). Enhanced SRIF release during a trough period of natural pulsatile GH secretion, suggested by the blunted GH response to exogenous hGHRH-analog, no longer occurred when major GH secretory bursts were abolished by GHRH-Ab treatment. On the other hand, when hGH was administered in GHRH-Ab-treated rats so as to simulate the quantity and dynamic change of GH in hypophysial portal circulation in rats exhibiting pulsatile GH secretion, hGHRH-analog-induced GH rises were significantly suppressed during the period corresponding to a GH trough. This suppression was completely prevented by simultaneous treatment with SRIF-Ab. Furthermore, administration of bovine GH, but not ovine prolactin, resulted in significant suppression of hGHRH-analog-provoked GH rises. These findings suggest that enhanced SRIF release during a trough period of spontaneous GH secretory rhythm is induced by the preceding GH secretory burst, and also suggest a possible role for SRIF-mediated GH autoregulation in a physiological state.

Using minimalist self-assembling peptides as hierarchical scaffolds to stabilise growth factors and promote stem cell integration in the injured brain.

PubMed

Rodriguez, A L; Bruggeman, K F; Wang, Y; Wang, T Y; Williams, R J; Parish, C L; Nisbet, D R

2018-03-01

Neurotrophic growth factors are effective in slowing progressive degeneration and/or promoting neural repair through the support of residual host and/or transplanted neurons. However, limitations including short half-life and enzyme susceptibility of growth factors highlight the need for alternative strategies to prolong localised delivery at a site of injury. Here, we establish the utility of minimalist N-fluorenylmethyloxycarbonyl (Fmoc) self-assembling peptides (SAPs) as growth factor delivery vehicle, targeted at supporting neural transplants in an animal model of Parkinson's disease. The neural tissue-specific SAP, Fmoc-DIKVAV, demonstrated sustained release of glial cell line derived neurotrophic factor, up to 172 hr after gel loading. This represents a significant advance in drug delivery, because its lifetime in phosphate buffered saline was less than 1 hr. In vivo transplantation of neural progenitor cells, together with our growth factor-loaded material, into the injured brain improved graft survival compared with cell transplants alone. We show for the first time the use of minimalist Fmoc-SAP in an in vivo disease model for sustaining the delivery of neurotrophic growth factors, facilitating their spatial and temporal delivery in vivo, whilst also providing an enhanced niche environment for transplanted cells. Copyright © 2017 John Wiley & Sons, Ltd.

Selenite-Releasing Bone Mineral Nanoparticles Retard Bone Tumor Growth and Improve Healthy Tissue Functions In Vivo.

PubMed

Wang, Yanhua; Hao, Hang; Liu, Haoming; Wang, Yifan; Li, Yan; Yang, Gaojie; Ma, Jun; Mao, Chuanbin; Zhang, Shengmin

2015-08-26

Selenite-doped bone mineral nanoparticles can retard the growth of osteosarcoma in a nude mice model, through sustained release of selenite ions. The selenite ions released from the nanoparticles through a degradation-mediated fashion inhibit tumor metastasis. Blood routine analysis indicates that selenite ions can also improve the functions of liver, kidney, and heart. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fibroblast Growth Factor 2: An Epithelial Ductal Cell Growth Inhibitor That Drops Out in Breast Cancer

DTIC Science & Technology

2009-10-01

AD_________________ Award Number: W81XWH-08-1-0708 TITLE: Fibroblast Growth Factor 2: an...September 2008 – 14 September 2009 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Fibroblast Growth Factor 2: an Epithelial Ductal Cell Growth Inhibitor...9 Fibroblast Growth Factor -2: an Epithelial Ductal Cell Growth Inhibitor that Drops Out in Breast Cancer

FACTORS RELATING TO THE RELEASE OF STACHYBOTRYS CHARTARUM SPORES FROM CONTAMINATED SOURCES

EPA Science Inventory

The paper describes preliminary results of a research project to determine the factors that control the release of S. chartarum spores from a contaminated source and test ways to reduce spore release and thus exposure. As anticipated, S. chartarum spore emissions from gypsum boar...

Effects of N-acetyl-L-cysteine on the membrane vesicle release and growth of respiratory pathogens.

PubMed

Volgers, Charlotte; Benedikter, Birke J; Grauls, Gert E; Hellebrand, Pauline H M; Savelkoul, Paul H M; Stassen, Frank R M

2017-05-01

Bacterial infections contribute to the disease progression of chronic obstructive pulmonary disease by stimulating mucus production in the airways. This increased mucus production and other symptoms are often alleviated when patients are treated with mucolytics such as N-acetyl-L-cysteine (NAC). Moreover, NAC has been suggested to inhibit bacterial growth. Bacteria can release membrane vesicles (MVs) in response to stress, and recent studies report a role for these proinflammatory MVs in the pathogenesis of airways disease. Yet, until now it is not clear whether NAC also affects the release of these MVs. This study set out to determine whether NAC, at concentrations reached during high-dose nebulization, affects bacterial growth and MV release of the respiratory pathogens non-typeable Haemophilus influenzae (NTHi), Moraxella catarrhalis (Mrc), Streptococcus pneumoniae (Spn) and Pseudomonas aeruginosa (Psa). We observed that NAC exerted a strong bacteriostatic effect, but also induced the release of proinflammatory MVs by NTHi, Mrc and Psa, but not by Spn. Interestingly, NAC also markedly blunted the release of TNF-α by naive macrophages in response to MVs. This suggests that the application of NAC by nebulization at a high dosage may be beneficial for patients with airway conditions associated with bacterial infections. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Cardiovascular actions of the ghrelin gene-derived peptides and growth hormone-releasing hormone.

PubMed

Granata, Riccarda; Isgaard, Jörgen; Alloatti, Giuseppe; Ghigo, Ezio

2011-05-01

In 1976, small peptide growth hormone secretagogues (GHSs) were discovered and found to promote growth hormone (GH) release from the pituitary. The GHS receptor (GHS-R) was subsequently cloned, and its endogenous ligand ghrelin was later isolated from the stomach. Ghrelin is a 28-amino acid peptide, whose acylation is essential for binding to GHS-R type 1a and for the endocrine functions, including stimulation of GH secretion and subsequent food intake. Unacylated ghrelin, the other ghrelin form, although devoid of GHS-R binding is an active peptide, sharing many peripheral effects with acylated ghrelin (AG). The ghrelin system is broadly expressed in myocardial tissues, where it exerts different functions. Indeed, ghrelin inhibits cardiomyocyte and endothelial cell apoptosis, and improves left ventricular (LV) function during ischemia-reperfusion (I/R) injury. In rats with heart failure (HF), ghrelin improves LV dysfunction and attenuates the development of cardiac cachexia. Similarly, ghrelin exerts vasodilatory effects in humans, improves cardiac function and decreases systemic vascular resistance in patients with chronic HF. Obestatin is a recently identified ghrelin gene peptide. The physiological role of obestatin and its binding to the putative GPR39 receptor are still unclear, although protective effects have been demonstrated in the pancreas and heart. Similarly to AG, the hypothalamic peptide growth hormone-releasing hormone (GHRH) stimulates GH release from the pituitary, through binding to the GHRH-receptor. Besides its proliferative effects in different cell types, at the cardiovascular level GHRH inhibits cardiomyocyte apoptosis, and reduces infarct size in both isolated rat heart after I/R and in vivo after myocardial infarction. Therefore, both ghrelin and GHRH exert cardioprotective effects, which make them candidate targets for therapeutic intervention in cardiovascular dysfunctions.

Endogenous versus Exogenous Growth Factor Regulation of Articular Chondrocytes

PubMed Central

Shi, Shuiliang; Chan, Albert G.; Mercer, Scott; Eckert, George J.; Trippel, Stephen B.

2014-01-01

Anabolic growth factors that regulate the function of articular chondrocytes are candidates for articular cartilage repair. Such factors may be delivered by pharmacotherapy in the form of exogenous proteins, or by gene therapy as endogenous proteins. It is unknown whether delivery method influences growth factor effectiveness in regulating articular chondrocyte reparative functions. We treated adult bovine articular chondrocytes with exogenous recombinant insulin-like growth factor-I (IGF-I) and transforming growth factor-beta1 (TGF-β1), or with the genes encoding these growth factors for endogenous production. Treatment effects were measured as change in chondrocyte DNA content, glycosaminoglycan production, and aggrecan gene expression. We found that IGF-I stimulated chondrocyte biosynthesis similarly when delivered by either exogenous or endogenous means. In contrast, exogenous TGF-ß1 stimulated these reparative functions, while endogenous TGF-ß1 had little effect. Endogenous TGF-ß1 became more bioactive following activation of the transgene protein product. These data indicate that effective mechanisms of growth factor delivery for articular cartilage repair may differ for different growth factors. In the case of IGF-I, gene therapy or protein therapy appear to be viable options. In contrast, TGF-ß1 gene therapy may be constrained by a limited ability of chondrocytes to convert latent complexes to an active form. PMID:24105960

Connective tissue growth factor is a substrate of ADAM28

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

Mochizuki, Satsuki; Tanaka, Rena; Shimoda, Masayuki

2010-11-26

Research highlights: {yields} The hyper-variable region in the cysteine-rich domain of ADAM28 binds to C-terminal domain of CTGF. {yields} ADAM28 cleaves CTGF alone and CTGF in the CTGF/VEGF{sub 165} complex. {yields} CTGF digestion by ADAM28 releases biologically active VEGF{sub 165} from the complex. {yields} ADAM28, CTGF and VEGF{sub 165} are commonly co-expressed by carcinoma cells in human breast carcinoma tissues. {yields} These suggest that ADAM28 promotes VEGF{sub 165}-induced angiogenesis in the breast carcinomas by selective CTGF digestion in the CTGF/VEGF{sub 165} complex. -- Abstract: ADAM28, a member of the ADAM (a disintegrin and metalloproteinase) gene family, is over-expressed by carcinomamore » cells and the expression correlates with carcinoma cell proliferation and progression in human lung and breast carcinomas. However, information about substrates of ADAM28 is limited. We screened interacting molecules of ADAM28 in human lung cDNA library by yeast two-hybrid system and identified connective tissue growth factor (CTGF). Binding of CTGF to proADAM28 was demonstrated by yeast two-hybrid assay and protein binding assay. ADAM28 cleaved CTGF in dose- and time-dependent manners at the Ala{sup 181}-Tyr{sup 182} and Asp{sup 191}-Pro{sup 192} bonds in the hinge region of the molecule. ADAM28 selectively digested CTGF in the complex of CTGF and vascular endothelial growth factor{sub 165} (VEGF{sub 165}), releasing biologically active VEGF{sub 165} from the complex. RT-PCR and immunohistochemical analyses demonstrated that ADAM28, CTGF and VEGF are commonly co-expressed in the breast carcinoma tissues. These data provide the first evidence that CTGF is a novel substrate of ADAM28 and suggest that ADAM28 may promote VEGF{sub 165}-induced angiogenesis in the breast carcinomas by the CTGF digestion in the CTGF/VEGF{sub 165} complex.« less

Fibroblast Growth Factors and Vascular Endothelial Growth Factor Promote Cardiac Reprogramming under Defined Conditions

PubMed Central

Yamakawa, Hiroyuki; Muraoka, Naoto; Miyamoto, Kazutaka; Sadahiro, Taketaro; Isomi, Mari; Haginiwa, Sho; Kojima, Hidenori; Umei, Tomohiko; Akiyama, Mizuha; Kuishi, Yuki; Kurokawa, Junko; Furukawa, Tetsushi; Fukuda, Keiichi; Ieda, Masaki

2015-01-01

Summary Fibroblasts can be directly reprogrammed into cardiomyocyte-like cells (iCMs) by overexpression of cardiac transcription factors, including Gata4, Mef2c, and Tbx5; however, this process is inefficient under serum-based culture conditions, in which conversion of partially reprogrammed cells into fully reprogrammed functional iCMs has been a major hurdle. Here, we report that a combination of fibroblast growth factor (FGF) 2, FGF10, and vascular endothelial growth factor (VEGF), termed FFV, promoted cardiac reprogramming under defined serum-free conditions, increasing spontaneously beating iCMs by 100-fold compared with those under conventional serum-based conditions. Mechanistically, FFV activated multiple cardiac transcriptional regulators and converted partially reprogrammed cells into functional iCMs through the p38 mitogen-activated protein kinase and phosphoinositol 3-kinase/AKT pathways. Moreover, FFV enabled cardiac reprogramming with only Mef2c and Tbx5 through the induction of cardiac reprogramming factors, including Gata4. Thus, defined culture conditions promoted the quality of cardiac reprogramming, and this finding provides new insight into the mechanism of cardiac reprogramming. PMID:26626177

Endorsement of Growth Factors in Experiential Training Groups

ERIC Educational Resources Information Center

Kiweewa, John; Gilbride, Dennis; Luke, Melissa; Seward, Derek

2013-01-01

The purpose of this study was to identify student growth factors during a semester long Master's level group counseling class. Results indicated that 12 growth factors accounted for 86% of the total number of critical incidents that participants reported as influencing their personal growth and awareness during the group experience. Two other…

Growth hormone releasing hormone (GHRH) signaling modulates intermittent hypoxia-induced oxidative stress and cognitive deficits in mouse.

PubMed

Nair, Deepti; Ramesh, Vijay; Li, Richard C; Schally, Andrew V; Gozal, David

2013-11-01

Intermittent hypoxia (IH) during sleep, such as occurs in obstructive sleep apnea (OSA), leads to degenerative changes in the hippocampus, and is associated with spatial learning deficits in adult mice. In both patients and murine models of OSA, the disease is associated with suppression of growth hormone (GH) secretion, which is actively involved in the growth, development, and function of the central nervous system (CNS). Recent work showed that exogenous GH therapy attenuated neurocognitive deficits elicited by IH during sleep in rats. Here, we show that administration of the Growth Hormone Releasing Hormone (GHRH) agonist JI-34 attenuates IH-induced neurocognitive deficits, anxiety, and depression in mice along with reduction in oxidative stress markers such as MDA and 8-hydroxydeoxyguanosine, and increases in hypoxia inducible factor-1α DNA binding and up-regulation of insulin growth factor-1 and erythropoietin expression. In contrast, treatment with a GHRH antagonist (MIA-602) during intermittent hypoxia did not affect any of the IH-induced deleterious effects in mice. Thus, exogenous GHRH administered as the formulation of a GHRH agonist may provide a viable therapeutic intervention to protect IH-vulnerable brain regions from OSA-associated neurocognitive dysfunction. Sleep apnea, characterized by chronic intermittent hypoxia (IH), is associated with substantial cognitive and behavioral deficits. Here, we show that administration of a GHRH agonist (JI-34) reduces oxidative stress, increases both HIF-1α nuclear binding and downstream expression of IGF1 and erythropoietin (EPO) in hippocampus and cortex, and markedly attenuates water maze performance deficits in mice exposed to intermittent hypoxia during sleep. © 2013 International Society for Neurochemistry.

Placenta Growth Factor in Diabetic Wound Healing

PubMed Central

Cianfarani, Francesca; Zambruno, Giovanna; Brogelli, Laura; Sera, Francesco; Lacal, Pedro Miguel; Pesce, Maurizio; Capogrossi, Maurizio C.; Failla, Cristina Maria; Napolitano, Monica; Odorisio, Teresa

2006-01-01

Reduced microcirculation and diminished expression of growth factors contribute to wound healing impairment in diabetes. Placenta growth factor (PlGF), an angiogenic mediator promoting pathophysiological neovascularization, is expressed during cutaneous wound healing and improves wound closure by enhancing angiogenesis. By using streptozotocin-induced diabetic mice, we here demonstrate that PlGF induction is strongly reduced in diabetic wounds. Diabetic transgenic mice overexpressing PlGF in the skin displayed accelerated wound closure compared with diabetic wild-type littermates. Moreover, diabetic wound treatment with an adenovirus vector expressing the human PlGF gene (AdCMV.PlGF) significantly accelerated the healing process compared with wounds treated with a control vector. The analysis of treated wounds showed that PlGF gene transfer improved granulation tissue formation, maturation, and vascularization, as well as monocytes/macrophages local recruitment. Platelet-derived growth factor, fibroblast growth factor-2, and vascular endothelial growth factor mRNA levels were increased in AdCMV.PlGF-treated wounds, possibly enhancing PlGF-mediated effects. Finally, PlGF treatment stimulated cultured dermal fibroblast migration, pointing to a direct role of PlGF in accelerating granulation tissue maturation. In conclusion, our data indicate that reduced PlGF expression contributes to impaired wound healing in diabetes and that PlGF gene transfer to diabetic wounds exerts therapeutic activity by promoting different aspects of the repair process. PMID:17003476

The impact of blood glucose levels on stimulated adrenocorticotropin hormone and growth hormone release in healthy subjects.

PubMed

Jakobsdóttir, S; Twisk, J W R; Drent, M L

2009-12-01

In studies investigating the influence of glucose levels on the pituitary function the methods used have been variable and mainly focused on the change in function as a reaction to unphysiological low or high blood glucose levels. In the present study the impact of physiological and elevated blood glucose levels on adrenocorticotropin hormone (ACTH) and growth hormone release are investigated. The euglycaemic and hyperglycaemic clamp techniques were used to reach stable levels of 4, 8 and 12 mmol/l blood glucose levels. After a stabilization phase of 2 h, a corticotropin releasing hormone (CRH) or a growth hormone releasing hormone (GHRH) stimulation test was performed. Seven and eight healthy male volunteers, belonging to two groups, participated in this study. The area under the curve (AUC), peak values and time to peak of ACTH, cortisol and growth hormone were calculated to evaluate the response to the CRH and GHRH stimulation test. The peak values of ACTH, cortisol and growth hormone seemed to be the highest during the 4 mmol/l clamp sessions, compared with the 8 and 12 mmol/l clamps, although the differences were not statistically significant when analysed for every subject individually. The AUC and time to peak measurements were comparable during the three clamp procedures. The pituitary reaction on CRH and GHRH was not significantly changed by various blood glucose levels. © 2009 Blackwell Publishing Ltd.

Scaffolds for Controlled Release of Cartilage Growth Factors.

PubMed

Morille, Marie; Venier-Julienne, Marie-Claire; Montero-Menei, Claudia N

2015-01-01

In recent years, cell-based therapies using adult stem cells have attracted considerable interest in regenerative medicine. A tissue-engineered construct for cartilage repair should provide a support for the cell and allow sustained in situ delivery of bioactive factors capable of inducing cell differentiation into chondrocytes. Pharmacologically active microcarriers (PAMs), made of biodegradable and biocompatible poly (D,L-lactide-co-glycolide acid) (PLGA), are a unique system which combines these properties in an adaptable and simple microdevice. This device relies on nanoprecipitation of proteins encapsulated in polymeric microspheres with a solid in oil in water emulsion-solvent evaporation process, and their subsequent coating with extracellular matrix protein molecules. Here, we describe their preparation process, and some of their characterization methods for an application in cartilage tissue engineering.

Cardiomyocyte-released factors stimulate oligodendrocyte precursor cells proliferation

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

Kuroda, Mariko; Muramatsu, Rieko; Precursory Research for Embryonic Science and Technology

The heart produces multiple diffusible factors that are involved in a number of physiological processes, but the action of these factors on the central nervous system is not well understood. In this study, we found that one or more factors released by cardiomyocytes promote oligodendrocyte precursor cell (OPC) proliferation in vitro. Mouse OPCs co-cultured with mouse cardiomyocytes showed higher proliferative ability than OPCs cultured alone. In addition, cardiomyocyte-conditioned media was sufficient to promote OPC proliferation. The phosphorylation of phosphatidylinositol (PI) 3-kinase and extracellular signal-regulated kinase (ERK) in OPCs is necessary for the enhancement of OPC proliferation by cardiomyocyte-conditioned media. These datamore » indicate that heart-derived factors have the ability to directly regulate the function of central nervous system (CNS) cells.« less

Fifth-year pine growth response to woody release treatments in young loblolly plantations

Treesearch

A.W. Ezell; J.L. Yeiser; L.R. Nelson

2013-01-01

The efficacy of adding Oust® XP to woody release treatments was evaluated on second-year pine plantations in Texas, Mississippi, and South Carolina. Overall, the residual control of herbaceous weeds on these sites was excellent the growing season following application. Pine height and diameter growth was evaluated for 5 years following application. Generally, the...

Fibroblast Growth Factor 2: An Epithelial Ductal Cell Growth Inhibitor That Drops Out in Breast Cancer

DTIC Science & Technology

2011-10-01

fibroblast   growth   factor   receptors  and  their  prognostic...AD_________________ Award Number: W81XWH-08-1-0708 TITLE: Fibroblast Growth Factor 2: an...September 2008 – 14 September 2011 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Fibroblast Growth Factor 2: an Epithelial Ductal Cell Growth

Therapeutic angiogenesis: angiogenic growth factors for ischemic heart disease.

PubMed

Henning, Robert J

2016-09-01

Stem cells encode vascular endothelial growth factors (VEGFs), fibroblastic growth factors (FGFs), stem cell factor, stromal cell-derived factor, platelet growth factor and angiopoietin that can contribute to myocardial vascularization. VEGFs and FGFs are the most investigated growth factors. VEGFs regulate angiogenesis and vasculogenesis. FGFs stimulate vessel cell proliferation and differentiation and are regulators of endothelial cell migration, proliferation and survival. Clinical trials of VEGF or FGF for myocardial angiogenesis have produced disparate results. The efficacy of therapeutic angiogenesis can be improved by: (1) identifying the most optimal patients; (2) increased knowledge of angiogenic factor pharmacokinetics and proper dose; (3) prolonging contact of angiogenic factors with the myocardium; (4) increasing the efficiency of VEGF or FGF gene transduction; and (5) utilizing PET or MRI to measure myocardial perfusion and perfusion reserve.

Corticotropin-Releasing Factor Mediates Pain-Induced Anxiety through the ERK1/2 Signaling Cascade in Locus Coeruleus Neurons

PubMed Central

Borges, Gisela Patrícia; Micó, Juan Antonio; Neto, Fani Lourença

2015-01-01

Background: The corticotropin-releasing factor is a stress-related neuropeptide that modulates locus coeruleus activity. As locus coeruleus has been involved in pain and stress-related patologies, we tested whether the pain-induced anxiety is a result of the corticotropin-releasing factor released in the locus coeruleus. Methods: Complete Freund’s adjuvant-induced monoarthritis was used as inflammatory chronic pain model. α-Helical corticotropin-releasing factor receptor antagonist was microinjected into the contralateral locus coeruleus of 4-week-old monoarthritic animals. The nociceptive and anxiety-like behaviors, as well as phosphorylated extracellular signal-regulated kinases 1/2 and corticotropin-releasing factor receptors expression, were quantified in the paraventricular nucleus and locus coeruleus. Results: Monoarthritic rats manifested anxiety and increased phosphorylated extracellular signal-regulated kinases 1/2 levels in the locus coeruleus and paraventricular nucleus, although the expression of corticotropin-releasing factor receptors was unaltered. α-Helical corticotropin-releasing factor antagonist administration reversed both the anxiogenic-like behavior and the phosphorylated extracellular signal-regulated kinases 1/2 levels in the locus coeruleus. Conclusions: Pain-induced anxiety is mediated by corticotropin-releasing factor neurotransmission in the locus coeruleus through extracellular signal-regulated kinases 1/2 signaling cascade. PMID:25716783

* Central Growth Factor Loaded Depots in Bone Tissue Engineering Scaffolds for Enhanced Cell Attraction.

PubMed

Quade, Mandy; Knaack, Sven; Akkineni, Ashwini Rahul; Gabrielyan, Anastasia; Lode, Anja; Rösen-Wolff, Angela; Gelinsky, Michael

2017-08-01

Tissue engineering, the application of stem and progenitor cells in combination with an engineered extracellular matrix, is a promising strategy for bone regeneration. However, its success is limited by the lack of vascularization after implantation. The concept of in situ tissue engineering envisages the recruitment of cells necessary for tissue regeneration from the host environment foregoing ex vivo cell seeding of the scaffold. In this study, we developed a novel scaffold system for enhanced cell attraction, which is based on biomimetic mineralized collagen scaffolds equipped with a central biopolymer depot loaded with chemotactic agents. In humid milieu, as after implantation, the signaling factors are expected to slowly diffuse out of the central depot forming a gradient that stimulates directed cell migration toward the scaffold center. Heparin, hyaluronic acid, and alginate have been shown to be capable of depot formation. By using vascular endothelial growth factor (VEGF) as model factor, it was demonstrated that the release kinetics can be adjusted by varying the depot composition. While alginate and hyaluronic acid are able to reduce the initial burst and prolong the release of VEGF, the addition of heparin led to a much stronger retention that resulted in an almost linear release over 28 days. The biological activity of released VEGF was proven for all variants using an endothelial cell proliferation assay. Furthermore, migration experiments with endothelial cells revealed a relationship between the degree of VEGF retention and migration distance: cells invaded deepest in scaffolds containing a heparin-based depot indicating that the formation of a steep gradient is crucial for cell attraction. In conclusion, this novel in situ tissue engineering approach, specifically designed to recruit and accommodate endogenous cells upon implantation, appeared highly promising to stimulate cell invasion, which in turn would promote vascularization and finally new

Impact of IGF-I release kinetics on bone healing: a preliminary study in sheep.

PubMed

Luginbuehl, Vera; Zoidis, Evangelos; Meinel, Lorenz; von Rechenberg, Brigitte; Gander, Bruno; Merkle, Hans P

2013-09-01

Spatiotemporal release of growth factors from a delivery device can profoundly affect the efficacy of bone growth induction. Here, we report on a delivery platform based on the encapsulation of insulin-like growth factor I (IGF-I) in different poly(D,L-lactide) (PLA) and poly(D,L-lactide-co-glycolide) (PLGA) microsphere (MS) formulations to control IGF-I release kinetics. In vitro IGF-I release profiles generally exhibited an initial burst (14-36% of total IGF-I content), which was followed by a more or less pronounced dormant phase with little release (2 to 34 days), and finally, a third phase of re-increased IGF-I release. The osteoinductive potential of these different IGF-I PL(G)A MS formulations was tested in studies using 8-mm metaphyseal drill hole bone defects in sheep. Histomorphometric analysis at 3 and 6 weeks after surgery showed that new bone formation was improved in the defects locally treated with IGF-I PL(G)A MS (n=5) as compared to defects filled with IGF-I-free PL(G)A MS (n=4). The extent of new bone formation was affected by the particular release kinetics, although a definitive relationship was not evident. Local administration of IGF-I resulted in down-regulation of inflammatory marker genes in all IGF-I treated defects. The over-expression of growth factor genes in response to IGF-I delivery was restricted to formulations that produced osteogenic responses. These experiments demonstrate the osteoinductive potential of sustained IGF-I delivery and show the importance of delivery kinetics for successful IGF-I-based therapies. Copyright © 2013 Elsevier B.V. All rights reserved.

Clinical Application of Growth Factors and Cytokines in Wound Healing

PubMed Central

Barrientos, Stephan; Brem, Harold; Stojadinovic, Olivera; Tomic-Canic, Marjana

2016-01-01

Wound healing is a complex and dynamic biological process that involves the coordinated efforts of multiple cell types and is executed and regulated by numerous growth factors and cytokines. There has been a drive in the past two decades to study the therapeutic effects of various growth factors in the clinical management of non-healing wounds (e.g. pressure ulcers, chronic venous ulcers, diabetic foot ulcers). For this review, we conducted a nonline search of Medline and Pub Medical and critically analyzed the literature regarding the role of growth factors and cytokines in the management of these wounds. We focused on currently approved therapies, emerging therapies and future research possibilities. In this review we discuss four growth factors and cytokines currently being used on and off label for the healing of wounds. These include: granulocyte-macrophage colony stimulating factor (GM-CSF), platelet derived growth factor (PDGF), vascular endothelial growth factor (VEGF), and basic fibroblast growth factor (bFGF). While the clinical results of using growth factors and cytokines are encouraging, many studies involved a small sample size and are disparate in measured endpoints. Therefore, further research is required to provide definitive evidence of efficacy. PMID:24942811

Ghrelin, a novel growth hormone-releasing peptide, in the treatment of cardiopulmonary-associated cachexia.

PubMed

Nagaya, Noritoshi; Kojima, Masakazu; Kangawa, Kenji

2006-01-01

Ghrelin is a novel growth hormone (GH)-releasing peptide, isolated from the stomach, which has been identified as an endogenous ligand for GH secretagogue receptor. The discovery of ghrelin indicates that the release of GH from the pituitary might be regulated not only by hypothalamic GH-releasing hormone, but also by ghrelin derived from the stomach. This peptide also stimulates food intake and induces adiposity through GH-independent mechanisms. In addition, ghrelin acts directly on the central nervous system to decrease sympathetic nerve activity. Thus, ghrelin plays important roles for maintaining GH release and energy homeostasis. Repeated administration of ghrelin improves body composition, muscle wasting, functional capacity, and sympathetic augmentation in cachectic patients with heart failure or chronic obstructive pulmonary disease. These results suggest that ghrelin has anti-cachectic effects through GH-dependent and independent mechanisms. Thus, administration of ghrelin may be a new therapeutic strategy for the treatment of cardiopulmonary-associated cachexia.

Divergent roles of growth factors in the GnRH regulation of puberty in mice

PubMed Central

DiVall, Sara A.; Williams, Tameeka R.; Carver, Sarah E.; Koch, Linda; Brüning, Jens C.; Kahn, C. Ronald; Wondisford, Fredric; Radovick, Sally; Wolfe, Andrew

2010-01-01

Pubertal onset, initiated by pulsatile gonadotropin-releasing hormone (GnRH), only occurs in a favorable, anabolic hormonal milieu. Anabolic factors that may signal nutritional status to the hypothalamus include the growth factors insulin and IGF-1. It is unclear which hypothalamic neuronal subpopulation these factors affect to ultimately regulate GnRH neuron function in puberty and reproduction. We examined the direct role of the GnRH neuron in growth factor regulation of reproduction using the Cre/lox system. Mice with the IR or IGF-1R deleted specifically in GnRH neurons were generated. Male and female mice with the IR deleted in GnRH neurons displayed normal pubertal timing and fertility, but male and female mice with the IGF-1R deleted in GnRH neurons experienced delayed pubertal development with normal fertility. With IGF-1 administration, puberty was advanced in control females, but not in females with the IGF-1R deleted in GnRH neurons, in control males, or in knockout males. These mice exhibited developmental differences in GnRH neuronal morphology but normal number and distribution of neurons. These studies define the role of IGF-1R signaling in the coordination of somatic development with reproductive maturation and provide insight into the mechanisms regulating pubertal timing in anabolic states. PMID:20628204

Advances in pubertal growth and factors influencing it: Can we increase pubertal growth?

PubMed Central

Soliman, Ashraf; De Sanctis, Vincenzo; Elalaily, Rania; Bedair, Said

2014-01-01

Puberty is a period of development characterized by partially concurrent changes which includes growth acceleration, alteration in body composition and appearance of secondary sex characteristics. Puberty is characterized by an acceleration and then deceleration in skeletal growth. The initiation, duration and amount of growth vary considerably during the growth spurt. Pubertal growth and biological maturation are dynamic processes regulated by a variety of genetic and environmental factors. Changes in skeletal maturation and bone mineral accretion concomitant with the stage of pubertal development constitute essential components in the evaluation of growth during this pubertal period. Genetic, endocrine and nutritional factors and ethnicity contribute variably to the amount of growth gained during this important period of rapid changes. Many studies investigated the possibility of increasing pubertal growth to gain taller final adult height in adolescents with idiopathic short stature (ISS). The pattern of pubertal growth, its relation to sex maturity rating and factors affecting them has been addressed in this review. The results of different trials to increase final adult height of adolescents using different hormones have been summarized. These data enables Endocrinologists to give in-depth explanations to patients and families about the efficacy and clinical significance as well as the safety of using these therapies in the treatment of adolescents with ISS. PMID:25538878

Intracellular processing of epidermal growth factor. I. Acidification of 125I-epidermal growth factor in intracellular organelles.

PubMed

Matrisian, L M; Planck, S R; Magun, B E

1984-03-10

We previously reported that 125I-labeled epidermal growth factor is processed intracellularly to acidic macromolecules in Rat-1 fibroblasts. The present study defines the precursor-product relationship and localization of the processing steps to subcellular organelles by the use of a single isoelectric species of 125I-epidermal growth factor and Percoll gradient fractionation. The native pI 4.55 125I-epidermal growth factor was rapidly processed to a pI 4.2 species on or near the cell surface and in organelles corresponding to clathrin-coated vesicles, Golgi, and endoplasmic reticulum. This species was then processed to a pI 4.35 species in similar organelles. The pI 4.2 and 4.35 species were converted to a pI 4.0 species in dense, lysosome-like organelles. This species was ultimately degraded and exocytosed from the cell as low molecular weight products.

Insulin-like growth factor-I and growth differentiation factor-5 promote the formation of tissue-engineered human nasal septal cartilage.

PubMed

Alexander, Thomas H; Sage, August B; Chen, Albert C; Schumacher, Barbara L; Shelton, Elliot; Masuda, Koichi; Sah, Robert L; Watson, Deborah

2010-10-01

Tissue engineering of human nasal septal chondrocytes offers the potential to create large quantities of autologous material for use in reconstructive surgery of the head and neck. Culture with recombinant human growth factors may improve the biochemical and biomechanical properties of engineered tissue. The objectives of this study were to (1) perform a high-throughput screen to assess multiple combinations of growth factors and (2) perform more detailed testing of candidates identified in part I. In part I, human nasal septal chondrocytes from three donors were expanded in monolayer with pooled human serum (HS). Cells were then embedded in alginate beads for 2 weeks of culture in medium supplemented with 2% or 10% HS and 1 of 90 different growth factor combinations. Combinations of insulin-like growth factor-I (IGF-1), bone morphogenetic protein (BMP)-2, BMP-7, BMP-13, growth differentiation factor-5 (GDF-5), transforming growth factor β (TGFβ)-2, insulin, and dexamethasone were evaluated. Glycosaminoglycan (GAG) accumulation was measured. A combination of IGF-1 and GDF-5 was selected for further testing based on the results of part I. Chondrocytes from four donors underwent expansion followed by three-dimensional alginate culture for 2 weeks in medium supplemented with 2% or 10% HS with or without IGF-1 and GDF-5. Chondrocytes and their associated matrix were then recovered and cultured for 4 weeks in 12 mm transwells in medium supplemented with 2% or 10% HS with or without IGF-1 and GDF-5 (the same medium used for alginate culture). Biochemical and biomechanical properties of the neocartilage were measured. In part I, GAG accumulation was highest for growth factor combinations including both IGF-1 and GDF-5. In part II, the addition of IGF-1 and GDF-5 to 2% HS resulted in a 12-fold increase in construct thickness compared with 2% HS alone (p < 0.0001). GAG and type II collagen accumulation was significantly higher with IGF-1 and GDF-5. Confined compression

Growth factor effects on costal chondrocytes for tissue engineering fibrocartilage

PubMed Central

Johns, D.E.; Athanasiou, K.A.

2010-01-01

Tissue engineered fibrocartilage could become a feasible option for replacing tissues like the knee meniscus or temporomandibular joint disc. This study employed five growth factors insulin-like growth factor-I, transforming growth factor-β1, epidermal growth factor, platelet-derived growth factor-BB, and basic fibroblast growth factor in a scaffoldless approach with costal chondrocytes, attempting to improve biochemical and mechanical properties of engineered constructs. Samples were quantitatively assessed for total collagen, glycosaminoglycans, collagen type I, collagen type II, cells, compressive properties, and tensile properties at two time points. Most treated constructs were worse than the no growth factor control, suggesting a detrimental effect, but the IGF treatment tended to improve the constructs. Additionally, the 6wk time point was consistently better than 3wks, with total collagen, glycosaminoglycans, and aggregate modulus doubling during this time. Further optimization of the time in culture and exogenous stimuli will be important in making a more functional replacement tissue. PMID:18597118

The future of recombinant growth factors in wound healing.

PubMed

Robson, M C; Mustoe, T A; Hunt, T K

1998-08-01

For more than a decade, clinical trials have been conducted of the application of topical exogenous recombinant growth factors in attempts to accelerate the healing of chronic wounds. Although the results of some of these trials have been encouraging, overall the results have been somewhat discouraging. Much of the difficulty lies in the paucity of carefully controlled clinical trials of wound healing. Since wound healing is a complex process that can be influenced, both positively and negatively, by many factors, designing these trials has proved difficult. To date, only a single recombinant growth factor-recombinant human platelet-derived growth factor-BB (rhPDGF-BB)- has been approved by the US Food and Drug Administration; and that only for use in diabetic foot ulcers. It is unlikely, however, that a single growth factor will be able to resolve all issues of repair or strengthen all vulnerabilities of chronic wounds. Our expectation, therefore, is that growth factors, cytokines, and other biologic agents will be used more specifically in the future, for example, by targeting growth factor therapy at those specific components or processes that a given wound uses to heal.

Effect of long-term administration of an analog of growth hormone-releasing factor on the GH response in rats.

PubMed

Karashima, T; Olsen, D; Schally, A V

1987-06-22

The effect of the repeated or continuous administration of an analog of GH releasing factor (GH-RF), D-Tyr-1, D-Ala-2, Nle-27, GH-RF(1-29)-NH2 (DBO-29), on the subsequent response to this peptide was investigated in pentobarbital-anesthetized male rats. A sc administration of this analog induced a greater and more prolonged GH release than doses 10 times larger of GH-RF(1-29). The GH increase after sc injection of 10 micrograms/kg bw of the analog was greater than that induced by iv administration of 2 micrograms/kg bw of GH-RF(1-44). Pretreatment with 10 micrograms/kg bw of the analog did not affect the pituitary response to a strong stimulus (20 micrograms/kg bw) of GH-RF(1-44), 24 h later. Pretreatment with the analog in doses of 10 micrograms/kg bw, sc twice a day, 5 days per week for 4 weeks, significantly diminished the GH release in response to a sc injection of the analog (10 micrograms/kg bw), as compared to vehicle-pretreated controls (P less than 0.01). On the other hand, a continuous sc administration of 0.4 micrograms/h of the analog to intact rats for 7 days did not result in a decrease in GH response to a sc injection of the analog (10 micrograms/kg bw). Since the rats injected repeatedly with the analog for 4 weeks still showed a marked, although somewhat reduced response, analogs of this type may be useful clinically.

Therapeutic potential of fibroblast growth factor-2 for hypertrophic scars: upregulation of MMP-1 and HGF expression.

PubMed

Eto, Hitomi; Suga, Hirotaka; Aoi, Noriyuki; Kato, Harunosuke; Doi, Kentaro; Kuno, Shinichiro; Tabata, Yasuhiko; Yoshimura, Kotaro

2012-02-01

Although hypertrophic scars (HTSs) and keloids are challenging problems, their pathogenesis is not well understood, making therapy difficult. We showed that matrix metalloproteinase (MMP)-1 expression was downregulated in HTS compared with normal skin from the same patients, whereas type 1 and 3 collagen and transforming growth factor-β (TGF-β) were upregulated. These differences, however, were not seen in cultured fibroblasts, suggesting the involvement of microenvironmental factors in the pathogenesis of HTS. Fibroblast growth factor-2 (FGF-2) highly upregulated the expression of MMP-1 and hepatocyte growth factor (HGF) in both HTS-derived and control fibroblasts; the upregulation was reversed by extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) inhibitors. An animal study using human HTS tissue implanted into nude mice indicated that controlled-release FGF-2 resulted in significantly less weight and decreased hydroxyproline content in HTS. Degradation of collagen fibers in FGF-2-treated HTS was also confirmed histologically. Western blotting showed that FGF-2-treated HTS expressed significantly higher MMP-1 protein than control. Decreased MMP-1 expression may be an important transcriptional change in HTS, and its reversal as well as upregulation of HGF by FGF-2 could be a new therapeutic approach for HTS.

Mesenchyme-derived factors enhance preneoplastic growth by non-genotoxic carcinogens in rat liver.

PubMed

Nejabat, Marzieh; Riegler, Teresa; Reitinger, Tabea; Subosits, Sandra; Römer, Michael; Eichner, Johannes; Bilban, Martin; Zell, Andreas; Huber, Wolfgang W; Schulte-Hermann, Rolf; Grasl-Kraupp, Bettina

2018-02-01

Many frequently prescribed drugs are non-genotoxic carcinogens (NGC) in rodent liver. Their mode of action and health risks for humans remain to be elucidated. Here, we investigated the impact of two model NGC, the anti-epileptic drug phenobarbital (PB) and the contraceptive cyproterone acetate (CPA), on intrahepatic epithelial-mesenchymal crosstalk and on growth of first stages of hepatocarcinogenesis. Unaltered hepatocytes (HC) and preneoplastic HC (HC PREN ) were isolated from rat liver for primary culture. DNA replication of HC and HC PREN was increased by in vitro treatment with 10 µM CPA, but not 1 mM PB. Next, mesenchymal cells (MC) obtained from liver of rats treated with either PB (50 mg/kg bw/day) or CPA (100 mg/kg bw/day), were cultured. Supernatants from both types of MC raised DNA synthesis of HC and HC PREN . This indicates that PB induces replication of HC and HC PREN only indirectly, via growth factors secreted by MC. CPA, however, acts on HC and HC PREN directly as well as indirectly via mesenchymal factors. Transcriptomics and bio-informatics revealed that PB and CPA induce extensive changes in the expression profile of MC affecting many growth factors and pathways. MC from PB-treated rats produced and secreted enhanced levels of HBEGF and GDF15, factors found to suppress apoptosis and/or induce DNA synthesis in cultured HC and HC PREN . MC from CPA-treated animals showed enhanced expression and secretion of HGF, which strongly raised DNA replication of HC and HC PREN . In conclusion, our findings reveal profound effects of two prototypical NGC on the hepatic mesenchyme. The resulting release of factors, which suppress apoptosis and/or enhance cell replication preferentially in cancer prestages, appears to be crucial for tumor promotion by NGC in the liver.

Fibroblast Growth Factors and Vascular Endothelial Growth Factor Promote Cardiac Reprogramming under Defined Conditions.

PubMed

Yamakawa, Hiroyuki; Muraoka, Naoto; Miyamoto, Kazutaka; Sadahiro, Taketaro; Isomi, Mari; Haginiwa, Sho; Kojima, Hidenori; Umei, Tomohiko; Akiyama, Mizuha; Kuishi, Yuki; Kurokawa, Junko; Furukawa, Tetsushi; Fukuda, Keiichi; Ieda, Masaki

2015-12-08

Fibroblasts can be directly reprogrammed into cardiomyocyte-like cells (iCMs) by overexpression of cardiac transcription factors, including Gata4, Mef2c, and Tbx5; however, this process is inefficient under serum-based culture conditions, in which conversion of partially reprogrammed cells into fully reprogrammed functional iCMs has been a major hurdle. Here, we report that a combination of fibroblast growth factor (FGF) 2, FGF10, and vascular endothelial growth factor (VEGF), termed FFV, promoted cardiac reprogramming under defined serum-free conditions, increasing spontaneously beating iCMs by 100-fold compared with those under conventional serum-based conditions. Mechanistically, FFV activated multiple cardiac transcriptional regulators and converted partially reprogrammed cells into functional iCMs through the p38 mitogen-activated protein kinase and phosphoinositol 3-kinase/AKT pathways. Moreover, FFV enabled cardiac reprogramming with only Mef2c and Tbx5 through the induction of cardiac reprogramming factors, including Gata4. Thus, defined culture conditions promoted the quality of cardiac reprogramming, and this finding provides new insight into the mechanism of cardiac reprogramming. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Co-delivery of vascular endothelial growth factor and angiopoietin-1 using injectable microsphere/hydrogel hybrid systems for therapeutic angiogenesis.

PubMed

Shin, Seung-Hwa; Lee, Jangwook; Ahn, Dong-Gyun; Lee, Kuen Yong

2013-08-01

We hypothesized that combined delivery of vascular endothelial growth factor (VEGF) and angiopoietin-1 (Ang-1) using microsphere/hydrogel hybrid systems could enhance mature vessel formation compared with administration of each factor alone. Hybrid delivery systems composed of alginate hydrogels and poly(D,L-lactic-co-glycolic acid) (PLGA) microspheres containing angiogenic factors were prepared. The release behavior of angiogenic factors from hybrid systems was monitored in vitro. The hybrid systems were injected into an ischemic rodent model, and blood vessel formation at the ischemic site was evaluated. The sustained release over 4 weeks of both VEGF and Ang-1 from hybrid systems was achieved in vitro. Co-delivery of VEGF and Ang-1 was advantageous to retain muscle tissues and significantly induced vessel enlargement at the ischemic site, compared to mice treated with either VEGF or Ang-1 alone. Sustained and combined delivery of VEGF and Ang-1 significantly enhances vessel enlargement at the ischemic site, compared with sustained delivery of either factor alone. Microsphere/hydrogel hybrid systems may be a promising vehicle for delivery of multiple drugs for many therapeutic applications.

The interrelationships of thyroid and growth hormones: effect of growth hormone releasing hormone in hypo- and hyperthyroid male rats.

PubMed

Root, A W; Shulman, D; Root, J; Diamond, F

1986-01-01

Growth hormone (GH) and the thyroid hormones interact in the hypothalamus, pituitary and peripheral tissues. Thyroid hormone exerts a permissive effect upon the anabolic and metabolic effects of GH, and increases pituitary synthesis of this protein hormone. GH depresses the secretion of thyrotropin and the thyroid hormones and increases the peripheral conversion of thyroxine to triiodothyronine. In the adult male rat experimental hypothyroidism produced by ingestion of propylthiouracil depresses the GH secretory response to GH-releasing hormone in vivo and in vitro, reflecting the lowered pituitary stores of GH in the hypothyroid state. Short term administration of large amounts of thyroxine with induction of the hyperthyroid state does not affect the in vivo GH secretory response to GH-releasing hormone in this animal.

Localisation of stem cell factor, stanniocalcin-1, connective tissue growth factor and heparin-binding epidermal growth factor in the bovine uterus at the time of blastocyst formation.

PubMed

Muñoz, M; Martin, D; Carrocera, S; Alonso-Guervos, M; Mora, M I; Corrales, F J; Peynot, N; Giraud-Delville, C; Duranthon, V; Sandra, O; Gómez, E

2017-10-01

Early embryonic losses before implantation account for the highest rates of reproductive failure in mammals, in particular when in vitro-produced embryos are transferred. In the present study, we used molecular biology techniques (real-time quantitative polymerase chain reaction), classical immunohistochemical staining coupled with confocal microscopy and proteomic analysis (multiple reaction monitoring and western blot analysis) to investigate the role of four growth factors in embryo-uterine interactions during blastocyst development. Supported by a validated embryo transfer model, the study investigated: (1) the expression of stem cell factor (SCF), stanniocalcin-1 (STC1), connective tissue growth factor (CTGF) and heparin-binding epidermal growth factor-like growth factor (HB-EGF) in bovine uterine fluid; (2) the presence of SCF, STC1, CTGF and HB-EGF mRNA and protein in the bovine endometrium and embryos; and (3) the existence of reciprocal regulation between endometrial and embryonic expression of SCF, STC1, CTGF and HB-EGF. The results suggest that these growth factors most likely play an important role during preimplantation embryo development in cattle. The information obtained from the present study can contribute to improving the performance of in vitro culture technology in cattle and other species.

Midcanopy growth following thinning in young-growth conifer forests on the Olympic Peninsula, western Washington

Treesearch

Emily J. Comfort; Scott D. Roberts; Constance A. Harrington

2010-01-01

Midcanopy layers are essential structures in "old-growth" forests on the Olympic Peninsula. Little is known about which stand and tree factors influence the ability of midcanopy trees in young-growth forests to respond to release; however, this information is important to managers interested in accelerating development of late-successional structural...

Temporal expression of growth factors triggered by epiregulin regulates inflammation development.

PubMed

Harada, Masaya; Kamimura, Daisuke; Arima, Yasunobu; Kohsaka, Hitoshi; Nakatsuji, Yuji; Nishida, Makoto; Atsumi, Toru; Meng, Jie; Bando, Hidenori; Singh, Rajeev; Sabharwal, Lavannya; Jiang, Jing-Jing; Kumai, Noriko; Miyasaka, Nobuyuki; Sakoda, Saburo; Yamauchi-Takihara, Keiko; Ogura, Hideki; Hirano, Toshio; Murakami, Masaaki

2015-02-01

In this study, we investigated the relationship between several growth factors and inflammation development. Serum concentrations of epiregulin, amphiregulin, betacellulin, TGF-α, fibroblast growth factor 2, placental growth factor (PLGF), and tenascin C were increased in rheumatoid arthritis patients. Furthermore, local blockades of these growth factors suppressed the development of cytokine-induced arthritis in mice by inhibiting chemokine and IL-6 expressions. We found that epiregulin expression was early and followed by the induction of other growth factors at different sites of the joints. The same growth factors then regulated the expression of epiregulin at later time points of the arthritis. These growth factors were increased in patients suffering from multiple sclerosis (MS) and also played a role in the development of an MS model, experimental autoimmune encephalomyelitis. The results suggest that the temporal expression of growth factors is involved in the inflammation development seen in several diseases, including rheumatoid arthritis and MS. Therefore, various growth factor pathways might be good therapeutic targets for various inflammatory diseases. Copyright © 2015 by The American Association of Immunologists, Inc.

The Effect of the Local Delivery of Platelet-derived Growth Factor from Reactive Two-Component Polyurethane Scaffolds on the Healing in Rat Skin Excisional Wounds

PubMed Central

Li, Bing; Davidson, Jeffrey M.; Guelcher, Scott A.

2009-01-01

A key tenet of tissue engineering is the principle that the scaffold can perform the dual roles of biomechanical and biochemical support through presentation of the appropriate mediators to surrounding tissue. While growth factors have been incorporated into scaffolds to achieve sustained release, there are a limited number of studies investigating release of biologically active molecules from reactive two-component polymers, which have potential application as injectable delivery systems. In this study, we report the sustained release of platelet-derived growth factor (PDGF) from a reactive two-component polyurethane. The release of PDGF was bi-phasic, characterized by an initial burst followed by a period of sustained release for up to 21 days. Despite the potential for amine and hydroxyl groups in the protein to react with the isocyanate groups in the reactive polyurethane, the in vitro bioactivity of the released PDGF was largely preserved when added as a lyophilized powder. PUR/PDGF scaffolds implanted in rat skin excisional wounds accelerated wound healing relative to the blank PUR control, resulting in almost complete healing with reepithelization at day 14. The presence of PDGF attracted both fibroblasts and mononuclear cells, significantly accelerating degradation of the polymer and enhancing formation of new granulation tissue as early as day 3. The ability of reactive two-component PUR scaffolds to promote new tissue formation in vivo through local delivery of PDGF may present compelling opportunities for the development of novel injectable therapeutics. PMID:19328544

A role of placental growth factor in hair growth.

PubMed

Yoon, Sun-Young; Yoon, Ji-Seon; Jo, Seong Jin; Shin, Chang Yup; Shin, Jong-Yeon; Kim, Jong-Il; Kwon, Ohsang; Kim, Kyu Han

2014-05-01

The dermal papilla (DP) comprises specialized mesenchymal cells at the bottom of the hair follicle and plays a pivotal role in hair formation, anagen induction and the hair cycle. In this study, DPs were isolated from human hair follicles and serially subcultured. From each subculture at passages 1, 3, and 5 (n=4), we compared gene expression profiles using mRNA sequencing. Among the growth factors that were down-regulated in later passages of human DP cells (hDPCs), placental growth factor (PlGF) was selected. To elucidate the effect of PlGF on hair growth. We evaluated the effect of PlGF on hDPCs and on ex vivo hair organ culture. We investigated the effect of PlGF on an in vivo model of depilation-induced hair regeneration. We confirmed that the mRNA and protein expression levels of PlGF significantly decreased following subculture of the cells. It was shown that PlGF enhanced hair shaft elongation in ex vivo hair organ culture. Furthermore, PlGF significantly accelerated hair follicle growth and markedly prolonged anagen hair growth in an in vivo model of depilation-induced hair regeneration. PlGF prevented cell death by increasing the levels of phosphorylated extracellular signal-regulated kinase (ERK) and cyclin D1 and promoted survival by up-regulation of phosphorylated Akt and Bcl2, as determined by Western blotting. Our results suggest that PlGF plays a role in the promotion of hair growth and therefore may serve as an additional therapeutic target for the treatment of alopecia. Copyright © 2014 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

The growth hormone-insulin-like growth factor axis in glycogen storage disease type 1: evidence of different growth patterns and insulin-like growth factor levels in patients with glycogen storage disease type 1a and 1b.

PubMed

Melis, Daniela; Pivonello, Rosario; Parenti, Giancarlo; Della Casa, Roberto; Salerno, Mariacarolina; Balivo, Francesca; Piccolo, Pasquale; Di Somma, Carolina; Colao, Annamaria; Andria, Generoso

2010-04-01

To investigate the growth hormone (GH)-insulin-like growth factor (IGF) system in patients with glycogen storage disease type 1 (GSD1). This was a prospective, case-control study. Ten patients with GSD1a and 7 patients with GSD1b who were given dietary treatment and 34 sex-, age-, body mass index-, and pubertal stage-matched control subjects entered the study. Auxological parameters were correlated with circulating GH, either at basal or after growth hormone releasing hormone plus arginine test, insulin-like growth factors (IGF-I and IGF-II), and anti-pituitary antibodies (APA). Short stature was detected in 10.0% of patients with GSD1a, 42.9% of patients with GSD1b (P = .02), and none of the control subjects. Serum IGF-I levels were lower in patients with GSD1b (P = .0001). An impaired GH secretion was found in 40% of patients with GSD1a (P = .008), 57.1% of patients with GSD1b (P = .006), and none of the control subjects. Short stature was demonstrated in 3 of 4 patients with GSD1b and GH deficiency. The prevalence of APA was significantly higher in patients with GSD1b than in patients with GSD1a (P = .02) and control subjects (P = .03). The GH response to the provocative test inversely correlated with the presence of APA (P = .003). Compared with levels in control subjects, serum IGF-II and insulin levels were higher in both groups of patients, in whom IGF-II levels directly correlated with height SD scores (P = .003). Patients with GSD1a have an impaired GH secretion associated with reference range serum IGF-I levels and normal stature, whereas in patients with GSD1b, the impaired GH secretion, probably because of the presence of APA, was associated with reduced IGF-I levels and increased prevalence of short stature. The increased IGF-II levels, probably caused by increased insulin levels, in patients with GSD1 are presumably responsible for the improved growth pattern observed in patients receiving strict dietary treatment. Copyright 2010 Mosby, Inc. All

Dual chain synthetic heparin-binding growth factor analogs

DOEpatents

Zamora, Paul O [Gaithersburg, MD; Pena, Louis A [Poquott, NY; Lin, Xinhua [Plainview, NY

2012-04-24

The invention provides synthetic heparin-binding growth factor analogs having two peptide chains each branched from a branch moiety, such as trifunctional amino acid residues, the branch moieties separated by a first linker of from 3 to about 20 backbone atoms, which peptide chains bind a heparin-binding growth factor receptor and are covalently bound to a non-signaling peptide that includes a heparin-binding domain, preferably by a second linker, which may be a hydrophobic second linker. The synthetic heparin-binding growth factor analogs are useful as pharmaceutical agents, soluble biologics or as surface coatings for medical devices.

Dual chain synthetic heparin-binding growth factor analogs

DOEpatents

Zamora, Paul O [Gaithersburg, MD; Pena, Louis A [Poquott, NY; Lin, Xinhua [Plainview, NY

2009-10-06

The invention provides synthetic heparin-binding growth factor analogs having two peptide chains each branched from a branch moiety, such as trifunctional amino acid residues, the branch moieties separated by a first linker of from 3 to about 20 backbone atoms, which peptide chains bind a heparin-binding growth factor receptor and are covalently bound to a non-signaling peptide that includes a heparin-binding domain, preferably by a second linker, which may be a hydrophobic second linker. The synthetic heparin-binding growth factor analogs are useful as pharmaceutical agents, soluble biologics or as surface coatings for medical devices.

Growth factors in urologic tissues: detection, characterization, and clinical applications.

PubMed

Mydlo, J H; Macchia, R J

1992-12-01

During the last two decades, enormous strides have been made in understanding cellular and molecular biology. The direction of treatment of many neoplasms and other diseases are starting at the microscopic level. Growth factors are polypeptides that play a part in the development and maintenance of living tissues. We, as well as others, have investigated the role that growth factors play particularly in urologic tissues, both benign and malignant. We review several well-known growth factors and their function in prostate, kidney, and bladder tissues, as well as their functions in other regulating processes of the human body, and also the use of growth factors as tumor markers, and antibodies to growth factors as possible treatment of disease.

Endothelial stress induces the release of vitamin D-binding protein, a novel growth factor

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

Raymond, Marc-Andre; Desormeaux, Anik; Labelle, Andree

2005-12-23

Endothelial cells (EC) under stress release paracrine mediators that facilitate accumulation of vascular smooth muscle cells (VSCM) at sites of vascular injury. We found that medium conditioned by serum-starved EC increase proliferation and migration of VSCM in vitro. Fractionation of the conditioned medium followed by mass spectral analysis identified one bioactive component as vitamin D-binding protein (DBP). DBP induced both proliferation and migration of VSMC in vitro in association with increased phosphorylation of ERK 1/2. PD 98059, a biochemical inhibitor of ERK 1/2, abrogated these proliferative and migratory responses in VSMC. DBP is an important carrier for the vitamin-D sterols,more » 25-hydroxyvitamin-D, and 1{alpha},25-dihydroxyvitamin-D. Both sterols inhibited the activity of DBP on VSMC, suggesting that vitamin D binding sites are important for initiating the activities of DBP on VSMC. Release of DBP at sites of endothelial injury represents a novel pathway favoring accumulation of VSMC at sites of vascular injury.« less

Insulin-like growth factor type-1 receptor down-regulation associated with dwarfism in Holstein calves.

PubMed

Blum, J W; Elsasser, T H; Greger, D L; Wittenberg, S; de Vries, F; Distl, O

2007-10-01

Perturbations in endocrine functions can impact normal growth. Endocrine traits were studied in three dwarf calves exhibiting retarded but proportionate growth and four phenotypically normal half-siblings, sired by the same bull, and four unrelated control calves. Plasma 3,5,3'-triiodothyronine and thyroxine concentrations in dwarfs and half-siblings were in the physiological range and responded normally to injected thyroid-releasing hormone. Plasma glucagon concentrations were different (dwarfs, controls>half-siblings; P<0.05). Plasma growth hormone (GH), insulin-like growth factor-1 (IGF-1) and insulin concentrations in the three groups during an 8-h period were similar, but integrated GH concentrations (areas under concentration curves) were different (dwarfs>controls, P<0.02; half-siblings>controls, P=0.08). Responses of GH to xylazine and to a GH-releasing-factor analogue were similar in dwarfs and half-siblings. Relative gene expression of IGF-1, IGF-2, GH receptor (GHR), insulin receptor, IGF-1 type-1 and -2 receptors (IGF-1R, IGF-2R), and IGF binding proteins were measured in liver and anconeus muscle. GHR mRNA levels were different in liver (dwarfs

Measles virus C protein suppresses gamma-activated factor formation and virus-induced cell growth arrest