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Sample records for dermal collagen implant

  1. Temporal variation in the deposition of different types of collagen within a porous biomaterial implant.

    PubMed

    White, Jacinta F; Werkmeister, Jerome A; Bisucci, Teresa; Darby, Ian A; Ramshaw, John A M

    2014-10-01

    The deposition of new collagen in association with a medical implant has been studied using expanded polytetrafluoroethylene vascular replacement samples implanted subcutaneously in sheep, for up to 28 days. New type I collagen mRNA synthesis was followed by in situ hybridization, while the accumulation of new collagen types III, V, VI, XII, and XIV was followed by immunohistochemistry. All the collagen detected in the pores of the implant were newly deposited at various times after implantation and were not due to any pre-existing dermal collagen that may have been present around the implant. Collagen deposition was seen initially surrounding the implant and, with time, was seen to infiltrate within its pores. In situ hybridization showed that the majority of infiltrating cells had switched on mRNA that coded for type I collagen production. Histology showed that cellular infiltration increased with time, accompanied by increasing collagen deposition. The deposition of different collagen types happened at different rates. The type V and VI collagens preceded the major interstitial collagens in the newly deposited tissue, although at longer time points, detection of type V collagen appeared to decrease. After disruption of the interstitial collagens with enzyme, the "masked" type V collagen was clearly still visible by immunohistochemistry. Little type XII collagen could be seen within the porous mesh, although it was seen in the surrounding tissues. By contrast, type XIV was seen throughout the porous structure of the implanted mesh, with less being visible outside the material where type XII was more abundant.

  2. Estrogen Depletion Results in Nanoscale Morphology Changes in Dermal Collagen

    PubMed Central

    Fang, Ming; Liroff, Kaitlin G.; Turner, A. Simon; Les, Clifford M.; Orr, Bradford G.; Holl, Mark M. Banaszak

    2012-01-01

    Tissue cryo-sectioning combined with Atomic Force Microscopy (AFM) imaging reveals that the nanoscale morphology of dermis collagen fibrils, quantified using the metric of D-periodic spacing, changes under the condition of estrogen depletion. Specifically, a new subpopulation of fibrils with D-spacings in the region between 56 and 59 nm is present two years following ovariectomy in ovine dermal samples. In addition, the overall width of the distribution, both values above and below the mean, has increased. The change in width due to an increase in lower values of D-spacings was previously reported for ovine bone; however, this report demonstrates that the effect is also present in non-mineralized collagen fibrils. A non-parametric Kolmogrov-Smirnov test of the cumulative density function indicates a statistical difference in the sham and OVX D-spacing distributions (p < 0.01). PMID:22437310

  3. Epidermal and dermal integration into sphere-templated porous poly(2-hydroxyethyl methacrylate) implants in mice.

    PubMed

    Fukano, Y; Usui, M L; Underwood, R A; Isenhath, S; Marshall, A J; Hauch, K D; Ratner, B D; Olerud, J E; Fleckman, P

    2010-09-15

    Percutaneous medical devices remain susceptible to infection and failure. We hypothesize that healing of the skin into the percutaneous device will provide a seal, preventing bacterial attachment, biofilm formation, and subsequent device failure. Porous poly(2-hydroxyethyl methacrylate) [poly(HEMA)] with sphere-templated pores (40 microm) and interconnecting throats (16 microm) were implanted in normal C57BL/6 mice for 7, 14, and 28 days. Poly(HEMA) was either untreated, keeping the surface nonadhesive for cells and proteins, or modified with carbonyldiimidazole (CDI) or CDI reacted with laminin 332 to enhance adhesion. No clinical signs of infection were observed. Epidermal and dermal response within the poly(HEMA) pores was evaluated using light and transmission electron microscopy. Cells (keratinocytes, fibroblasts, endothelial cells, inflammatory cells) and basement membrane proteins (laminin 332, beta4 integrin, type VII collagen) could be demonstrated within the poly(HEMA) pores of all implants. Blood vessels and dermal collagen bundles were evident in all of the 14- and 28-day implants. Fibrous capsule formation and permigration were not observed. Sphere-templated polymers with 40 microm pores demonstrate an ability to recapitulate key elements of both the dermal and the epidermal layers of skin. Our morphological findings indicate that the implant model can be used to study the effects of biomaterial pore size, pore interconnect (throat) size, and surface treatments on cutaneous biointegration. Further, this model may be used for bacterial challenge studies.

  4. Dermal type I collagen assessment by digital image analysis*

    PubMed Central

    Brianezi, Gabrielli; Grandi, Fabrizio; Bagatin, Ediléia; Enokihara, Mílvia Maria S. S.; Miot, Hélio Amante

    2015-01-01

    Type I collagen is the main dermal component, and its evaluation is relevant to quantitative studies in dermatopathology. However, visual gradation (0 to 4+) has low precision and high subjectivity levels. This study aimed to develop and validate a digital morphometric analysis technique to estimate type I collagen levels in the papillary dermis. Four evaluators visually quantified (0 to 4+) the density of type I collagen in 63 images of forearm skin biopsies marked by immunohistochemistry and two evaluators analyzed the same images using digital morphometric techniques (RGB split colors (I) and color deconvolution (II)). Automated type I collagen density estimation in the papillary dermis (two techniques) were correlated with visual evaluations (Spearman's rho coefficients of 0.48 and 0.62 (p<0.01)). With regard to the inter-observer repeatability, the four evaluators who used visual classification had an intraclass correlation coefficient (for absolute agreement) of 0.53, while the other two evaluators who used digital analysis (algorithm II) had an intraclass correlation coefficient of 0.97. PMID:26560217

  5. Collagen-Binding Peptidoglycans Inhibit MMP Mediated Collagen Degradation and Reduce Dermal Scarring

    PubMed Central

    Snyder, Paul W.; Freeman, Lynetta; Panitch, Alyssa

    2011-01-01

    Scarring of the skin is a large unmet clinical problem that is of high patient concern and impact. Wound healing is complex and involves numerous pathways that are highly orchestrated, leaving the skin sealed, but with abnormal organization and composition of tissue components, namely collagen and proteoglycans, that are then remodeled over time. To improve healing and reduce or eliminate scarring, more rapid restoration of healthy tissue composition and organization offers a unique approach for development of new therapeutics. A synthetic collagen-binding peptidoglycan has been developed that inhibits matrix metalloproteinase-1 and 13 (MMP-1 and MMP-13) mediated collagen degradation. We investigated the synthetic peptidoglycan in a rat incisional model in which a single dose was delivered in a hyaluronic acid (HA) vehicle at the time of surgery prior to wound closure. The peptidoglycan treatment resulted in a significant reduction in scar tissue at 21 days as measured by histology and visual analysis. Improved collagen architecture of the treated wounds was demonstrated by increased tensile strength and transmission electron microscopy (TEM) analysis of collagen fibril diameters compared to untreated and HA controls. The peptidoglycan's mechanism of action includes masking existing collagen and inhibiting MMP-mediated collagen degradation while modulating collagen organization. The peptidoglycan can be synthesized at low cost with unique design control, and together with demonstrated preclinical efficacy in reducing scarring, warrants further investigation for dermal wound healing. PMID:21779387

  6. Cytotoxic evaluation of biomechanically improved crosslinked ovine collagen on human dermal fibroblasts.

    PubMed

    Awang, M A; Firdaus, M A B; Busra, M B; Chowdhury, S R; Fadilah, N R; Wan Hamirul, W K; Reusmaazran, M Y; Aminuddin, M Y; Ruszymah, B H I

    2014-01-01

    Earlier studies in our laboratory demonstrated that collagen extracted from ovine tendon is biocompatible towards human dermal fibroblast. To be able to use this collagen as a scaffold in skin tissue engineering, a mechanically stronger scaffold is required that can withstand manipulation before transplantation. This study was conducted to improve the mechanical strength of this collagen sponge using chemical crosslinkers, and evaluate their effect on physical, chemical and biocompatible properties. Collagen sponge was crosslinked with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and glutaraldehyde (GA). Tensile test, FTIR study and mercury porosimetry were used to evaluate mechanical properties, chemical property and porosity, respectively. MTT assay was performed to evaluate the cytotoxic effect of crosslinked collagen sponge on human dermal fibroblasts. The FTIR study confirmed the successful crosslinking of collagen sponge. Crosslinking with EDC and GA significantly increased the mechanical strength of collagen sponge, with GA being more superior. Crosslinking of collagen sponge significantly reduced the porosity and the effect was predominant in GA-crosslinked collagen sponge. The GA-crosslinked collagen showed significantly lower, 60% cell viability towards human dermal fibroblasts compared to that of EDC-crosslinked collagen, 80% and non-crosslinked collagen, 100%. Although the mechanical strength was better when using GA but the more toxic effect on dermal fibroblast makes EDC a more suitable crosslinker for future skin tissue engineering.

  7. Preparation of (3H)collagen for studies of the biologic fate of xenogenic collagen implants in vivo

    SciTech Connect

    McPherson, J.M.; Sawamura, S.J.; Conti, A.

    1986-06-01

    Reduction of a commercially available, pepsin-solubilized, bovine dermal collagen (Vitrogen 100) with sodium (3H)borohydride provided radiolabeled collagen preparations with specific activities ranging from 7.1-12.0 muCi/mg collagen. These specific activities were 2-3 times greater than those obtained by reduction of intact rat tail tendon collagen under similar conditions. The alpha, beta, and higher aggregate components of type I collagen were radiolabeled as well as the alpha component of a small amount of type III collagen present in the samples. Fractionation of cyanogen bromide peptides showed that alpha 1(I)CB7, alpha 1(I)CB8, and alpha 2(I)CB3,5 were the predominant peptides labeled by this procedure. Amino acid analysis indicated that the majority of the radioactivity was in reducible cross-links, precursors of these cross-links, and in hexosyllysine residues. Reconstitution experiments comparing this radiolabeled collagen with nonlabeled collagen showed them to be indistinguishable. Bacterial collagenase digestion of this reconstituted fibrillar collagen in both a lightly cross-linked (glutaraldehyde 0.0075%) and noncross-linked form provided evidence that digestion of labeled and nonlabeled collagens proceeded at similar rates. Thus, labeling did not change the properties of the collagen. Cross-linking made the preparation refractory to proteolytic degradation. Injection of fibrillar collagen preparations, spiked with radiolabeled collagen, into the guinea pig dermis followed by quantitation of the amount of radioactivity recovered from implant sites as a function of time, indicated that the lightly cross-linked samples also were more resistant to degradation in vivo than the noncross-linked preparation. The half-life of noncross-linked collagen was about 4 days while that of the cross-linked collagen was about 25 days.

  8. Laminin peptide YIGSR induces collagen synthesis in Hs27 human dermal fibroblasts.

    PubMed

    Yoon, Jong Hyuk; Kim, Jaeyoon; Lee, Hyeongjoo; Kim, So Young; Jang, Hwan-Hee; Ryu, Sung Ho; Kim, Beom Joon; Lee, Taehoon G

    2012-11-23

    The dermal ECM is synthesized from fibroblasts and is primarily compromised of fibrillar collagen and elastic fibers, which support the mechanical strength and resiliency of skin, respectively. Laminin, a major glycoprotein located in the basement membrane, promotes cell adhesion, cell growth, differentiation, and migration. The laminin tyrosine-isoleucine-glycine-serine-arginine (YIGSR) peptide, corresponding to the 929-933 sequence of the β1 chain, is known to be a functional motif with effects on the inhibition of tumor metastasis, the regulation of sensory axonal response and the inhibition of angiogenesis through high affinity to the 67kDa laminin receptor. In this study, we identified a novel function of the YIGSR peptide to enhance collagen synthesis in human dermal fibroblasts. To elucidate this novel function regarding collagen synthesis, we treated human dermal fibroblasts with YIGSR peptide in both a time- and dose-dependent manner. According to subsequent experiments, we found that the YIGSR peptide strongly enhanced collagen type 1 synthesis without changing cell proliferation or cellular MMP-1 level. This YIGSR peptide-mediated collagen type 1 synthesis was modulated by FAK inhibitor and MEK inhibitor. This study clearly reveals that YIGSR peptide plays a novel function on the collagen type 1 synthesis of dermal fibroblasts and also suggests that YIGSR is a strong candidate peptide for the treatment of skin aging and wrinkles.

  9. Laminin peptide YIGSR induces collagen synthesis in Hs27 human dermal fibroblasts

    SciTech Connect

    Yoon, Jong Hyuk; Kim, Jaeyoon; Lee, Hyeongjoo; Kim, So Young; Jang, Hwan-Hee; Ryu, Sung Ho; Kim, Beom Joon; Lee, Taehoon G.

    2012-11-23

    Highlights: Black-Right-Pointing-Pointer We identify a function of the YIGSR peptide to enhance collagen synthesis in Hs27. Black-Right-Pointing-Pointer YIGSR peptide enhanced collagen type 1 synthesis both of gene and protein levels. Black-Right-Pointing-Pointer There were no changes in cell proliferation and MMP-1 level in YIGSR treatment. Black-Right-Pointing-Pointer The YIGSR effect on collagen synthesis mediated activation of FAK, pyk2 and ERK. Black-Right-Pointing-Pointer The YIGSR-induced FAK and ERK activation was modulated by FAK and MEK inhibitors. -- Abstract: The dermal ECM is synthesized from fibroblasts and is primarily compromised of fibrillar collagen and elastic fibers, which support the mechanical strength and resiliency of skin, respectively. Laminin, a major glycoprotein located in the basement membrane, promotes cell adhesion, cell growth, differentiation, and migration. The laminin tyrosine-isoleucine-glycine-serine-arginine (YIGSR) peptide, corresponding to the 929-933 sequence of the {beta}1 chain, is known to be a functional motif with effects on the inhibition of tumor metastasis, the regulation of sensory axonal response and the inhibition of angiogenesis through high affinity to the 67 kDa laminin receptor. In this study, we identified a novel function of the YIGSR peptide to enhance collagen synthesis in human dermal fibroblasts. To elucidate this novel function regarding collagen synthesis, we treated human dermal fibroblasts with YIGSR peptide in both a time- and dose-dependent manner. According to subsequent experiments, we found that the YIGSR peptide strongly enhanced collagen type 1 synthesis without changing cell proliferation or cellular MMP-1 level. This YIGSR peptide-mediated collagen type 1 synthesis was modulated by FAK inhibitor and MEK inhibitor. This study clearly reveals that YIGSR peptide plays a novel function on the collagen type 1 synthesis of dermal fibroblasts and also suggests that YIGSR is a strong candidate

  10. In vivo visualization of dermal collagen fiber in skin burn by collagen-sensitive second-harmonic-generation microscopy

    NASA Astrophysics Data System (ADS)

    Tanaka, Ryosuke; Fukushima, Shu-ichiro; Sasaki, Kunihiko; Tanaka, Yuji; Murota, Hiroyuki; Matsumoto, Takeshi; Araki, Tsutomu; Yasui, Takeshi

    2013-06-01

    Optical assessment of skin burns is possible with second-harmonic-generation (SHG) microscopy due to its high sensitivity to thermal denaturation of collagen molecules. In contrast to previous studies that were performed using excised tissue specimens ex vivo, in vivo observation of dermal collagen fibers in living rat burn models with SHG microscopy is demonstrated. Changes in signal vanishing patterns in the SHG images are confirmed to be dependent on the burn degree. Comparison of the SHG images with Masson's trichrome-stained images indicated that the observed patterns were caused by the coexistence of molten and fibrous structures of dermal collagen fibers. Furthermore, a quantitative parameter for burn assessment based on the depth profile of the mean SHG intensity across the entire SHG image is proposed. These results and discussions imply a potential of SHG microscopy as a minimally invasive, highly quantitative tool for skin burn assessment.

  11. Neck Contracture Release With Matriderm Collagen/Elastin Dermal Matrix

    PubMed Central

    Greenwood, John E.; Mackie, Ian P.

    2011-01-01

    Aims: To demonstrate success with immediate split-skin graft application over Matriderm dermal matrix in a difficult neck contracture release. Methods: An aggressive neck contracture release, accompanied by complete platysmectomy, was followed by application of Matriderm, split-skin graft, Mepitel, and vacuum-assisted closure (VAC) dressing. Results: At VAC removal (day 7), graft take was almost complete over the dermal matrix and with minor “touch-up” were complete by day 9 postrepair. Results at 4 months show graft contraction and a marked diminution of the release obtained. The results, however, are still good and the patient is very happy. Conclusion: Immediate grafting over a dermal matrix appears to provide a good solution, with a gentle surgical learning curve, in this difficult postburn scenario. Postrelease contraction is, however, as inevitable as with other techniques. PMID:21451729

  12. Apigenin induces dermal collagen synthesis via smad2/3 signaling pathway.

    PubMed

    Zhang, Y; Wang, J; Cheng, X; Yi, B; Zhang, X; Li, Q

    2015-04-13

    Decrease in fibroblast-produced collagen has been proven to be the pivotal cause of skin aging, but there is no satisfactory drug which directly increases dermal thickness and collage density. Here we found that a flavonoid natural product, apigenin, could significantly increase collagen synthesis. NIH/3T3 and primary human dermal fibroblasts (HDFs) were incubated with various concentrations of apigenin, with dimethyl sulfoxide (DMSO) serving as the negative control. Real-time reverse-transcription polymerase chain reaction (PCR), Western Blot, and Toluidine blue staining demonstrated that apigenin stimulated type-I and type-III collagen synthesis of fibroblasts on the mRNA and protein levels. Meanwhile, apigenin did not induce expression of alpha smooth muscle actin (α-SMA) in vitro and in vivo, a fibrotic marker in living tissues. Then the production of collagen was confirmed by Masson's trichrome stain, Picrosirius red stain and immunohistochemistry in mouse models. We also clarified that this compound induced collagen synthesis by activating smad2/3 signaling pathway. Taken together, without obvious influence on fibroblasts' apoptosis and viability, apigenin could promote the type-I and type-III collagen synthesis of dermal fibroblasts in vitro and in vivo, thus suggesting that apigenin may serve as a potential agent for esthetic and reconstructive skin rejuvenation.

  13. Apigenin Induces Dermal Collagen Synthesis Via smad2/3 Signaling Pathway

    PubMed Central

    Zhang, Y.; Wang, J.; Cheng, X.; Yi, B.; Zhang, X.; Li, Q.

    2015-01-01

    Decrease in fibroblast-produced collagen has been proven to be the pivotal cause of skin aging, but there is no satisfactory drug which directly increases dermal thickness and collage density. Here we found that a flavonoid natural product, apigenin, could significantly increase collagen synthesis. NIH/3T3 and primary human dermal fibroblasts (HDFs) were incubated with various concentrations of apigenin, with dimethyl sulfoxide (DMSO) serving as the negative control. Real-time reverse-transcription polymerase chain reaction (PCR), Western Blot, and Toluidine blue staining demonstrated that apigenin stimulated type-I and type-III collagen synthesis of fibroblasts on the mRNA and protein levels. Meanwhile, apigenin did not induce expression of alpha smooth muscle actin (α-SMA) in vitro and in vivo, a fibrotic marker in living tissues. Then the production of collagen was confirmed by Masson’s trichrome stain, Picrosirius red stain and immunohistochemistry in mouse models. We also clarified that this compound induced collagen synthesis by activating smad2/3 signaling pathway. Taken together, without obvious influence on fibroblasts’ apoptosis and viability, apigenin could promote the type-I and type-III collagen synthesis of dermal fibroblasts in vitro and in vivo, thus suggesting that apigenin may serve as a potential agent for esthetic and reconstructive skin rejuvenation. PMID:26150153

  14. In vivo imaging of dermal collagen in skin burn by collagen-sensitive second-harmonic-generation microscopy

    NASA Astrophysics Data System (ADS)

    Yasui, Takeshi; Tanaka, Ryosuke; Hase, Eiji; Fukushima, Shu-ichiro; Araki, Tsutomu

    2013-02-01

    Optical assessment of skin burns is possible with second-harmonic-generation (SHG) microscopy due to its high sensitivity to thermal denaturation of collagen molecules. In contrast to previous studies that were performed using excised tissue specimens ex vivo, in this study, we demonstrated in vivo observation of dermal collagen fibers in living rat burn models with SHG microscopy. We confirmed that changes in SHG vanishing patterns in the SHG images depended on the burn degree. The results imply that SHG microscopy can be used as a low-invasiveness, highly quantitative tool for skin burn assessment.

  15. Mesenchymal Stem Cells Increase Collagen Infiltration and Improve Wound Healing Response to Porous Titanium Percutaneous Implants

    PubMed Central

    Isackson, Dorthyann; Cook, Kevin J.; McGill, Lawrence D.; Bachus, Kent N.

    2012-01-01

    Epidermal downgrowth, commonly associated with long-term percutaneous implants, weakens the skin-implant seal and greatly increases the vulnerability of the site to infection. To improve the skin attachment and early tissue integration with porous metal percutaneous implants, we evaluated the effect of bone marrow-derived mesenchymal stem cells (BMMSCs) to provide wound healing cues and vascularization to the dermal and epidermal tissues in establishing a barrier with the implant. Two porous metal percutaneous implants, one treated with BMMSCs and one untreated, were placed subdermally on the dorsum of Lewis rats. Implants were evaluated at 0, 3, 7, 28, and 56 days after implantation. Histological analyses evaluated cellular infiltrates, vascularization, quantity and quality of tissue ingrowth, epidermal downgrowth, and fibrous encapsulation. The amount of collagen infiltrating the porous coating was significantly greater for the BMMSC-treated implants at 3 and 28 days post implantation compared to untreated implants. There was an early influx and resolution of cellular inflammatory infiltrates in the treated implants compared to the untreated, though not statistically significant. Vascularization increased over time in both treated and untreated implants, with no statistical significance. Epidermal downgrowth was minimally observed in all implants with or without the BMMSC treatment. Our results suggest that BMMSCs can influence an early and rapid resolution of acute and chronic inflammation in wound healing, and can stimulate early collagen deposition and granulation tissue associated with later stages of wound repair. These findings provide evidence that BMMSCs can stimulate a more rapid and improved barrier between the skin and porous metal percutaneous implant. PMID:22940446

  16. Effects of Panax ginseng extract on human dermal fibroblast proliferation and collagen synthesis.

    PubMed

    Lee, Geum-Young; Park, Kang-Gyun; Namgoong, Sik; Han, Seung-Kyu; Jeong, Seong-Ho; Dhong, Eun-Sang; Kim, Woo-Kyung

    2016-03-01

    Current studies of Panax ginseng (or Korean ginseng) have demonstrated that it has various biological effects, including angiogenesis, immunostimulation, antimicrobial and anti-inflammatory effects. Therefore, we hypothesised that P. ginseng may also play an important role in wound healing. However, few studies have been conducted on the wound-healing effects of P. ginseng. Thus, the purpose of this in vitro pilot study was to determine the effects of P. ginseng on the activities of fibroblasts, which are key wound-healing cells. Cultured human dermal fibroblasts were treated with one of six concentrations of P. ginseng: 0, 1, 10 and 100 ng/ml and 1 and 10 µg/ml. Cell proliferation was determined 3 days post-treatment using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide assay, and collagen synthesis was evaluated by the collagen type I carboxy-terminal propeptide method. Cell proliferation levels and collagen synthesis were compared among the groups. The 10 ng/ml to 1 µg/ml P. ginseng treatments significantly increased cell proliferation, and the 1 ng/ml to 1 µg/ml concentrations significantly increased collagen synthesis. The maximum effects for both parameters were observed at 10 ng/ml. P. ginseng stimulated human dermal fibroblast proliferation and collagen synthesis at an optimal concentration of 10 ng/ml.

  17. Effect of Collagen Nanotopography on Keloid Fibroblast Proliferation and Matrix Synthesis: Implications for Dermal Wound Healing

    PubMed Central

    Muthusubramaniam, Lalitha; Zaitseva, Tatiana; Paukshto, Michael; Martin, George

    2014-01-01

    Keloids are locally exuberant dermal scars characterized by excessive fibroblast proliferation and matrix accumulation. Although treatment strategies include surgical removal and intralesional steroid injections, an effective regimen is yet to be established due to a high rate of recurrence. The regressing center and growing margin of the keloid have different collagen architecture and also differ in the rate of proliferation. To investigate whether proliferation is responsive to collagen topography, keloid, scar, and dermal fibroblasts were cultured on nanopatterned scaffolds varying in collagen fibril diameter and alignment-small and large diameter, aligned and random fibrils, and compared to cells grown on flat collagen-coated substrates, respectively. Cell morphology, proliferation, and expression of six genes related to proliferation (cyclin D1), phenotype (α-smooth muscle actin), and matrix synthesis (collagens I and III, and matrix metalloproteinase-1 and -2) were measured to evaluate cell response. Fibril alignment was shown to reduce proliferation and matrix synthesis in all three types of fibroblasts. Further, keloid cells were found to be most responsive to nanotopography. PMID:24724556

  18. Collagen-Based Films Containing Liposome-Loaded Usnic Acid as Dressing for Dermal Burn Healing

    PubMed Central

    Nunes, Paula S.; Albuquerque-Júnior, Ricardo L. C.; Cavalcante, Danielle R. R.; Dantas, Marx D. M.; Cardoso, Juliana C.; Bezerra, Marília S.; Souza, Jamille C. C.; Serafini, Mairim Russo; Quitans-Jr, Lucindo J.; Bonjardim, Leonardo R.; Araújo, Adriano A. S.

    2011-01-01

    The aim of this study was assess the effect of collagen-based films containing usnic acid as a wound dressing for dermal burn healing. Second-degree burn wounds were performed in forty-five Wistar rats, assigned into nine groups: COL—animals treated with collagen-based films; PHO—animals treated with collagen films containing empty liposomes; UAL—animals treated with collagen-based films containing usnic acid incorporated into liposomes. After 7, 14, and 21 days the animals were euthanized. On 7th day there was a moderate infiltration of neutrophils, in UAL, distributed throughout the burn wounds, whereas in COL and PHO, the severity of the reaction was slighter and still limited to the margins of the burn wounds. On the 14th day, the inflammatory reaction was less intense in UAL, with remarkable plasma cells infiltration. On the 21st day, there was reduction of the inflammation, which was predominantly composed of plasma cells in all groups, particularly in UAL. The use of the usnic acid provided more rapid substitution of type-III for type-I collagen on the 14th day, and improved the collagenization density on the 21st day. It was concluded that the use of reconstituted bovine type-I collagen-based films containing usnic acid improved burn healing process in rats. PMID:21274404

  19. Engineered Pullulan–Collagen Composite Dermal Hydrogels Improve Early Cutaneous Wound Healing

    PubMed Central

    Wong, Victor W.; Rustad, Kristine C.; Galvez, Michael G.; Neofytou, Evgenios; Glotzbach, Jason P.; Januszyk, Michael; Major, Melanie R.; Sorkin, Michael; Longaker, Michael T.; Rajadas, Jayakumar

    2011-01-01

    New strategies for skin regeneration are needed to address the significant medical burden caused by cutaneous wounds and disease. In this study, pullulan–collagen composite hydrogel matrices were fabricated using a salt-induced phase inversion technique, resulting in a structured yet soft scaffold for skin engineering. Salt crystallization induced interconnected pore formation, and modification of collagen concentration permitted regulation of scaffold pore size. Hydrogel architecture recapitulated the reticular distribution of human dermal matrix while maintaining flexible properties essential for skin applications. In vitro, collagen hydrogel scaffolds retained their open porous architecture and viably sustained human fibroblasts and murine mesenchymal stem cells and endothelial cells. In vivo, hydrogel-treated murine excisional wounds demonstrated improved wound closure, which was associated with increased recruitment of stromal cells and formation of vascularized granulation tissue. In conclusion, salt-induced phase inversion techniques can be used to create modifiable pullulan–collagen composite dermal scaffolds that augment early wound healing. These novel biomatrices can potentially serve as a structured delivery template for cells and biomolecules in regenerative skin applications. PMID:20919949

  20. The exclusion of human serum albumin by human dermal collagenous fibres and within human dermis.

    PubMed Central

    Bert, J L; Mathieson, J M; Pearce, R H

    1982-01-01

    Preparations of dermal collagenous fibres and slices of human dermis have been equilibrated with 125I-labelled monomeric human serum albumin. The space inaccessible to the albumin in the fibres and in the dermis was determined by subtraction of the accessible space, calculated from the radioactivity of the specimen, from its total fluid. For a fibre preparation examined in detail, the fluid exclusion was independent of the concentration of either albumin or collagen. Binding of albumin to the fibres was not demonstrable. Three fibre preparations excluded albumin from 3.75 +/- 0.96, 3.55 +/- 0.67, and 2.05 +/- 0.39 g of fluid/g of collagen (+/-S.D.). Slices from three specimens of dermis excluded albumin from 1.45 +/- 0.08 g of fluid/g of insoluble solids or 1.57 +/- 0.11 g of fluid/g of collagen (+/-S.D.). Thus the exclusion of albumin by dermis was much less than expected from its content of collagenous fibres. On the basis of these data and the published composition of dermis, the concentration of albumin in the accessible interstitial space was estimated to be close to that in the plasma. PMID:7082298

  1. Preparation and characterization of an advanced collagen aggregate from porcine acellular dermal matrix.

    PubMed

    Liu, Xinhua; Dan, Nianhua; Dan, Weihua

    2016-07-01

    The objective of this study was to extract and characterize an advanced collagen aggregate (Ag-col) from porcine acellular dermal matrix (pADM). Based on histological examination, scanning electron microscopy (SEM) and atomic force microscope (AFM), Ag-col was composed of the D-periodic cross-striated collagen fibrils and thick collagen fiber bundles with uneven diameters and non-orientated arrangement. Fourier transform infrared (FTIR) spectra of pADM, Ag-col and Col were similar and revealed the presence of the triple helix. Circular dichroism (CD) analysis exhibited a slightly higher content of α-helix but inappreciably less amount of random coil structure in Ag-col compared to Col. Moreover, imino acid contents of pADM, Ag-col and Col were 222.43, 218.30 and 190.01 residues/1000 residues, respectively. From zeta potential analysis, a net charge of zero was found at pH 6.45 and 6.11 for Ag-col and Col, respectively. Differential scanning calorimetry (DSC) study suggested that the Td of Ag-col was 20°C higher than that of Col as expected, and dynamic mechanical analysis (DMA) indicated that Ag-col possessed a higher storage modulus but similar loss factor compared to Col. Therefore, the collagen aggregate from pADM could serve as a better alternative source of collagens for further applications in food and biological industries.

  2. Fibroblast migration and collagen deposition during dermal wound healing: mathematical modelling and clinical implications.

    PubMed

    McDougall, Steven; Dallon, John; Sherratt, Jonathan; Maini, Philip

    2006-06-15

    The extent to which collagen alignment occurs during dermal wound healing determines the severity of scar tissue formation. We have modelled this using a multiscale approach, in which extracellular materials, for example collagen and fibrin, are modelled as continua, while fibroblasts are considered as discrete units. Within this model framework, we have explored the effects that different parameters have on the alignment process, and we have used the model to investigate how manipulation of transforming growth factor-beta levels can reduce scar tissue formation. We briefly review this body of work, then extend the modelling framework to investigate the role played by leucocyte signalling in wound repair. To this end, fibroblast migration and collagen deposition within both the wound region and healthy peripheral tissue are considered. Trajectories of individual fibroblasts are determined as they migrate towards the wound region under the combined influence of collagen/fibrin alignment and gradients in a paracrine chemoattractant produced by leucocytes. The effects of a number of different physiological and cellular parameters upon the collagen alignment and repair integrity are assessed. These parameters include fibroblast concentration, cellular speed, fibroblast sensitivity to chemoattractant concentration and chemoattractant diffusion coefficient. Our results show that chemoattractant gradients lead to increased collagen alignment at the interface between the wound and the healthy tissue. Results show that there is a trade-off between wound integrity and the degree of scarring. The former is found to be optimized under conditions of a large chemoattractant diffusion coefficient, while the latter can be minimized when repair takes place in the presence of a competitive inhibitor to chemoattractants.

  3. The linker-free covalent attachment of collagen to plasma immersion ion implantation treated polytetrafluoroethylene and subsequent cell-binding activity.

    PubMed

    Bax, Daniel V; McKenzie, David R; Weiss, Anthony S; Bilek, Marcela M M

    2010-03-01

    It is desirable that polymers used for the fabrication of prosthetic implants promote biological functions such as cellular adhesion, differentiation and viability. In this study, we have used plasma immersion ion implantation (PIII) to modify the surface of polytetrafluoroethylene (PTFE), thereby modulating the binding mechanism of collagen. The amount of collagen bound to the polymer surface following PIII-treatment was similar to that bound by non-covalent physisorption. In a manner consistent with previous enzyme and tropoelastin binding data, the collagen bound to the PIII-treated PTFE surface was resistant to sodium dodecyl sulfate (SDS) elution whilst collagen bound to the untreated surface was fully removed. This demonstrates the capability of PIII-treated surfaces to covalently attach collagen without employing chemical linking molecules. Only the collagen bound to the PIII-treated PTFE surface supported human dermal fibroblast attachment and spreading. This indicates that collagen on the PIII-treated surface possesses increased adhesive activity as compared to that on the untreated surface. Cell adhesion was inhibited by EDTA when the collagen was bound to PIII-treated PTFE, as expected for integrin involvement. Additionally this adhesion was sensitive to the conformation of the bound collagen. Increased actin cytoskeletal assembly was observed on cells spreading onto collagen-coated PIII-treated PTFE compared to the collagen-coated untreated PTFE. These data demonstrate the retention of collagen's biological properties following its attachment to PIII-treated PTFE, suggesting advantages for tissue engineering and prosthetic design.

  4. Multiphoton microscopy of engineered dermal substitutes: assessment of 3D collagen matrix remodeling induced by fibroblasts contraction

    NASA Astrophysics Data System (ADS)

    Pena, A.-M.; Olive, C.; Michelet, J.-F.; Galey, J.-B.; Fagot, D.; Leroy, F.; Martin, J.-L.; Colonna, A.; Schanne-Klein, M.-C.

    2010-02-01

    One of the main functions of dermal fibroblasts is the generation of mechanical forces within their surrounding extracellular matrix. Investigating molecules that could modulate fibroblast contraction and act as potent anti aging ingredients requires the development of three-dimensional in situ imaging methodologies for dermal substitute analysis. Here we use multiphoton microscopy in order to investigate the fibroblast-induced collagen matrix reorganization in engineered dermal tissue and to evaluate the effect of Y27632, a RhoA kinase inhibitor on dermal substitutes contraction. We observe that collagen fibrils rearrange around fibroblast with increasing density in control samples, whereas collagen fibrils show no remodeling in the samples containing the RhoA kinase inhibitor. Moreover, when the culture medium containing the inhibitor was replaced with a control medium, the dermal substitutes presented the same 3D reorganization as the control samples, which indicates that the inhibitory effects are reversible. In conclusion, our study demonstrates the relevance of multiphoton microscopy to visualize three-dimensional remodeling of the matrix induced by fibroblast contraction.

  5. Glucose oxidase incorporated collagen matrices for dermal wound repair in diabetic rat models: a biochemical study.

    PubMed

    Arul, V; Masilamoni, J G; Jesudason, E P; Jaji, P J; Inayathullah, M; Dicky John, D G; Vignesh, S; Jayakumar, R

    2012-05-01

    Impaired wound healing in diabetes is a well-documented phenomenon. Emerging data favor the involvement of free radicals in the pathogenesis of diabetic wound healing. We investigated the beneficial role of the sustained release of reactive oxygen species (ROS) in diabetic dermal wound healing. In order to achieve the sustained delivery of ROS in the wound bed, we have incorporated glucose oxidase in the collagen matrix (GOIC), which is applied to the healing diabetic wound. Our in vitro proteolysis studies on incorporated GOIC show increased stability against the proteases in the collagen matrix. In this study, GOIC film and collagen film (CF) are used as dressing material on the wound of streptozotocin-induced diabetic rats. A significant increase in ROS (p < 0.05) was observed in the fibroblast of GOIC group during the inflammation period compared to the CF and control groups. This elevated level up regulated the antioxidant status in the granulation tissue and improved cellular proliferation in the GOIC group. Interestingly, our biochemical parameters nitric oxide, hydroxyproline, uronic acid, protein, and DNA content in the healing wound showed that there is an increase in proliferation of cells in GOIC when compared to the control and CF groups. In addition, evidence from wound contraction and histology reveals faster healing in the GOIC group. Our observations document that GOIC matrices could be effectively used for diabetic wound healing therapy.

  6. Investigation of the effect of hydration on dermal collagen in ex vivo human skin tissue using second harmonic generation microscopy

    NASA Astrophysics Data System (ADS)

    Samatham, Ravikant; Wang, Nicholas K.; Jacques, Steven L.

    2016-02-01

    Effect of hydration on the dermal collagen structure in human skin was investigated using second harmonic generation microscopy. Dog ears from the Mohs micrographic surgery department were procured for the study. Skin samples with subject aged between 58-90 years old were used in the study. Three dimensional Multiphoton (Two-photon and backward SHG) control data was acquired from the skin samples. After the control measurement, the skin tissue was either soaked in deionized water for 2 hours (Hydration) or kept at room temperature for 2 hours (Desiccation), and SHG data was acquired. The data was normalized for changes in laser power and detector gain. The collagen signal per unit volume from the dermis was calculated. The desiccated skin tissue gave higher backward SHG compared to respective control tissue, while hydration sample gave a lower backward SHG. The collagen signal decreased with increase in hydration of the dermal collagen. Hydration affected the packing of the collagen fibrils causing a change in the backward SHG signal. In this study, the use of multiphoton microscopy to study the effect of hydration on dermal structure was demonstrated in ex vivo tissue.

  7. Multiphoton microscopy of engineered dermal substitutes: assessment of 3-D collagen matrix remodeling induced by fibroblast contraction

    NASA Astrophysics Data System (ADS)

    Pena, Ana-Maria; Fagot, Dominique; Olive, Christian; Michelet, Jean-François; Galey, Jean-Baptiste; Leroy, Frédéric; Beaurepaire, Emmanuel; Martin, Jean-Louis; Colonna, Anne; Schanne-Klein, Marie-Claire

    2010-09-01

    Dermal fibroblasts are responsible for the generation of mechanical forces within their surrounding extracellular matrix and can be potentially targeted by anti-aging ingredients. Investigation of the modulation of fibroblast contraction by these ingredients requires the implementation of three-dimensional in situ imaging methodologies. We use multiphoton microscopy to visualize unstained engineered dermal tissue by combining second-harmonic generation that reveals specifically fibrillar collagen and two-photon excited fluorescence from endogenous cellular chromophores. We study the fibroblast-induced reorganization of the collagen matrix and quantitatively evaluate the effect of Y-27632, a RhoA-kinase inhibitor, on dermal substitute contraction. We observe that collagen fibrils rearrange around fibroblasts with increasing density in control samples, whereas collagen fibrils show no remodeling in the samples containing the RhoA-kinase inhibitor. Moreover, we show that the inhibitory effects are reversible. Our study demonstrates the relevance of multiphoton microscopy to visualize three-dimensional remodeling of the extracellular matrix induced by fibroblast contraction or other processes.

  8. Replacement of animal-derived collagen matrix by human fibroblast-derived dermal matrix for human skin equivalent products.

    PubMed

    El Ghalbzouri, Abdoelwaheb; Commandeur, Suzan; Rietveld, Marion H; Mulder, Aat A; Willemze, Rein

    2009-01-01

    Reconstructed human skin equivalents (HSEs) are representative models of human skin and widely used for research purposes and clinical applications. Traditional methods to generate HSEs are based on the seeding of human keratinocytes onto three-dimensional human fibroblast-populated non-human collagen matrices. Current HSEs have a limited lifespan of approximately 8 weeks, rendering them unsuitable for long-term studies. Here we present a new generation of HSEs being fully composed of human components and which can be cultured up to 20 weeks. This model is generated on a primary human fibroblast-derived dermal matrix. Pro-collagen type I secretion by human fibroblasts stabilized during long-term culture, providing a continuous and functional human dermal matrix. In contrast to rat-tail collagen-based HSEs, the present fibroblast-derived matrix-based HSEs contain more continuity in the number of viable cell layers in long-term cultures. In addition, these new skin models exhibit normal differentiation and proliferation, based on expression of K10/K15, and K16/K17, respectively. Detection of collagen types IV and VII and laminin 332 was confined to the epidermal-dermal junction, as in native skin. The presence of hemidesmosomes and anchoring fibrils was demonstrated by electron microscopy. Finally, we show that the presented HSE contained a higher concentration of the normal moisturizing factor compared to rat-tail collagen-based skin models, providing a further representation of functional normal human skin in vitro. This study, therefore, demonstrates the role of the dermal microenvironment on epidermal regeneration and lifespan in vitro.

  9. Modulation of human dermal microvascular endothelial cell and human gingival fibroblast behavior by micropatterned silica coating surfaces for zirconia dental implant applications.

    PubMed

    Laranjeira, Marta S; Carvalho, Ângela; Pelaez-Vargas, Alejandro; Hansford, Derek; Ferraz, Maria Pia; Coimbra, Susana; Costa, Elísio; Santos-Silva, Alice; Fernandes, Maria Helena; Monteiro, Fernando Jorge

    2014-04-01

    Dental ceramic implants have shown superior esthetic behavior and the absence of induced allergic disorders when compared to titanium implants. Zirconia may become a potential candidate to be used as an alternative to titanium dental implants if surface modifications are introduced. In this work, bioactive micropatterned silica coatings were produced on zirconia substrates, using a combined methodology of sol-gel processing and soft lithography. The aim of the work was to compare the in vitro behavior of human gingival fibroblasts (HGFs) and human dermal microvascular endothelial cells (HDMECs) on three types of silica-coated zirconia surfaces: flat and micropatterned (with pillars and with parallel grooves). Our results showed that cells had a higher metabolic activity (HGF, HDMEC) and increased gene expression levels of fibroblast-specific protein-1 (FSP-1) and collagen type I (COL I) on surfaces with pillars. Nevertheless, parallel grooved surfaces were able to guide cell growth. Even capillary tube-like networks of HDMEC were oriented according to the surface geometry. Zirconia and silica with different topographies have shown to be blood compatible and silica coating reduced bacteria adhesion. All together, the results indicated that microstructured bioactive coating seems to be an efficient strategy to improve soft tissue integration on zirconia implants, protecting implants from peri-implant inflammation and improving long-term implant stabilization. This new approach of micropatterned silica coating on zirconia substrates can generate promising novel dental implants, with surfaces that provide physical cues to guide cells and enhance their behavior.

  10. Modulation of human dermal microvascular endothelial cell and human gingival fibroblast behavior by micropatterned silica coating surfaces for zirconia dental implant applications

    PubMed Central

    Laranjeira, Marta S; Carvalho, Ângela; Pelaez-Vargas, Alejandro; Hansford, Derek; Ferraz, Maria Pia; Coimbra, Susana; Costa, Elísio; Santos-Silva, Alice; Fernandes, Maria Helena; Monteiro, Fernando Jorge

    2014-01-01

    Dental ceramic implants have shown superior esthetic behavior and the absence of induced allergic disorders when compared to titanium implants. Zirconia may become a potential candidate to be used as an alternative to titanium dental implants if surface modifications are introduced. In this work, bioactive micropatterned silica coatings were produced on zirconia substrates, using a combined methodology of sol–gel processing and soft lithography. The aim of the work was to compare the in vitro behavior of human gingival fibroblasts (HGFs) and human dermal microvascular endothelial cells (HDMECs) on three types of silica-coated zirconia surfaces: flat and micropatterned (with pillars and with parallel grooves). Our results showed that cells had a higher metabolic activity (HGF, HDMEC) and increased gene expression levels of fibroblast-specific protein-1 (FSP-1) and collagen type I (COL I) on surfaces with pillars. Nevertheless, parallel grooved surfaces were able to guide cell growth. Even capillary tube-like networks of HDMEC were oriented according to the surface geometry. Zirconia and silica with different topographies have shown to be blood compatible and silica coating reduced bacteria adhesion. All together, the results indicated that microstructured bioactive coating seems to be an efficient strategy to improve soft tissue integration on zirconia implants, protecting implants from peri-implant inflammation and improving long-term implant stabilization. This new approach of micropatterned silica coating on zirconia substrates can generate promising novel dental implants, with surfaces that provide physical cues to guide cells and enhance their behavior. PMID:27877662

  11. Modulation of human dermal microvascular endothelial cell and human gingival fibroblast behavior by micropatterned silica coating surfaces for zirconia dental implant applications

    NASA Astrophysics Data System (ADS)

    Laranjeira, Marta S.; Carvalho, Ângela; Pelaez-Vargas, Alejandro; Hansford, Derek; Ferraz, Maria Pia; Coimbra, Susana; Costa, Elísio; Santos-Silva, Alice; Fernandes, Maria Helena; Monteiro, Fernando Jorge

    2014-04-01

    Dental ceramic implants have shown superior esthetic behavior and the absence of induced allergic disorders when compared to titanium implants. Zirconia may become a potential candidate to be used as an alternative to titanium dental implants if surface modifications are introduced. In this work, bioactive micropatterned silica coatings were produced on zirconia substrates, using a combined methodology of sol-gel processing and soft lithography. The aim of the work was to compare the in vitro behavior of human gingival fibroblasts (HGFs) and human dermal microvascular endothelial cells (HDMECs) on three types of silica-coated zirconia surfaces: flat and micropatterned (with pillars and with parallel grooves). Our results showed that cells had a higher metabolic activity (HGF, HDMEC) and increased gene expression levels of fibroblast-specific protein-1 (FSP-1) and collagen type I (COL I) on surfaces with pillars. Nevertheless, parallel grooved surfaces were able to guide cell growth. Even capillary tube-like networks of HDMEC were oriented according to the surface geometry. Zirconia and silica with different topographies have shown to be blood compatible and silica coating reduced bacteria adhesion. All together, the results indicated that microstructured bioactive coating seems to be an efficient strategy to improve soft tissue integration on zirconia implants, protecting implants from peri-implant inflammation and improving long-term implant stabilization. This new approach of micropatterned silica coating on zirconia substrates can generate promising novel dental implants, with surfaces that provide physical cues to guide cells and enhance their behavior.

  12. Expression of catalytically active Matrix Metalloproteinase-1 in dermal fibroblasts induces collagen fragmentation and functional alterations that resemble aged human skin

    PubMed Central

    Xia, Wei; Hammerberg, Craig; Li, Yong; He, Tianyuan; Quan, Taihao; Voorhees, John J; Fisher, Gary J

    2013-01-01

    Summary Increased expression of matrix metalloproteinase-1 (MMP-1) and reduced production of type I collagen by dermal fibroblasts are prominent features of aged human skin. We have proposed that MMP-1-mediated collagen fibril fragmentation is a key driver of age-related decline of skin function. To investigate this hypothesis, we constructed, characterized, and expressed constitutively active MMP-1 mutant (MMP-1 V94G) in adult human skin in organ culture and fibroblasts in three dimensional collagen lattice cultures. Expression of MMP-1 V94G in young skin in organ culture caused fragmentation and ultrastructural alterations of collagen fibrils similar to those observed in aged human skin in vivo. Expression of MMP-1 V94G in dermal fibroblasts cultured in three-dimensional collagen lattices caused substantial collagen fragmentation, which was markedly reduced by MMP-1 siRNA-mediated knockdown or MMP inhibitor MMI270. Importantly, fibroblasts cultured in MMP-1 V94G-fragmented collagen lattices displayed many alterations observed in fibroblasts in aged human skin, including reduced cytoplasmic area, disassembled actin cytoskeleton, impaired TGF-β pathway, and reduced collagen production. These results support the concept that MMP-1-mediated fragmentation of dermal collagen fibrils alters the morphology and function of dermal fibroblasts, and provide a foundation for understanding specific mechanisms that link collagen fibril fragmentation to age-related decline of fibroblast function. PMID:23601157

  13. Effect of crosslinking on the performance of a collagen-derived biomaterial as an implant for soft tissue repair: a rodent model.

    PubMed

    de Castro Brás, Lisandra E; Proffitt, Joanne L; Bloor, Steve; Sibbons, Paul D

    2010-11-01

    One of the main problems in healthcare is the loss of tissues resulting from diseases, post-surgery complications or trauma. As a result there is a need for biomaterials designed to promote tissue regeneration and improve wound healing. This study assessed the effect of crosslinking of a porcine dermal collagen matrix with regard to strength of implant/host tissue integration, implant biocompatibility and general healing in a rodent model. Permacol™, a crosslinked acellular collagenous biomaterial was compared with its noncrosslinked equivalent at 3, 6, and 12 months postsubcutaneous implantation. Both matrices were well tolerated and showed no evidence of inflammation or adverse responses either in the host tissue or implants. Progressive integration of the implants with the surrounding tissue was observed. Cellular response was similar for both collagenous matrices although, at 3 and 6 months, noncrosslinked implants showed a significantly higher level of cellular penetration than crosslinked implants. However, at 12 months crosslinked implants showed significantly higher levels of cellular density, neo-vascularisation and integration with host tissue. Additionally, at long term, noncrosslinked implants lost volume suggesting some absorption. The crosslinking process does not seem to be detrimental to cellular response and biocompatibility.

  14. Periplanosides A-C: new insect-derived dihydroisocoumarin glucosides from Periplaneta americana stimulating collagen production in human dermal fibroblasts.

    PubMed

    Yang, Yong-Xun; Luo, Qi; Hou, Bo; Yan, Yong-Ming; Wang, Yue-Hu; Tang, Jian-Jun; Dong, Xiao-Ping; Ma, Xiu-Ying; Yang, Tong-Hua; Zuo, Zhi-Li; Cheng, Yong-Xian

    2015-01-01

    Three new dihydroisocoumarin glucosides, termed periplanosides A-C (1-3), a known analog, pericanaside (4), and the other twenty known compounds were isolated from the insect Periplaneta americana. Their structures including absolute configurations were determined by comprehensive spectroscopic analyses and computational methods. Biological evaluation showed that compound 2 could stimulate collagen production by 31.2% in human dermal fibroblasts-adult (HDFa) at the concentration of 30 μM, indicating its significance in skin repair and ulcer.

  15. Modulation of heat shock protein 90 affects TGF-β-induced collagen synthesis in human dermal fibroblast cells.

    PubMed

    Lee, Sae Bin; Lim, A-Ram; Rah, Dong Kyun; Kim, Kyung Soo; Min, Hyun Jin

    2016-12-01

    Heat shock protein 90 is a chaperone molecule that aids in proper folding of target proteins. Recently, heat shock protein 90 was found to play a role in would healing through regulation of fibroblast functions. The aim of the present study was to investigate the role of heat shock protein 90 in collagen synthesis in human dermal fibroblasts. The effects of transforming growth factor-β, 17-N-allylamino-17-demethoxygeldanamycin, and transfection of heat shock protein 90 were evaluated by real-time PCR, western blot, and immunofluorescence assays. The Smad 2/3 and Akt pathways were evaluated to identify the signaling pathways involved in collagen synthesis. Heat shock protein 90 and collagen levels were compared in keloid and control tissues by immunohistochemical analysis. The expression of collagen was significantly increased after treatment with transforming growth factor-β, while 17-N-allylamino-17-demethoxygeldanamycin inhibited transforming growth factor-β-induced collagen synthesis. Overexpression of heat shock protein 90 itself with or without transforming growth factor-β increased collagen synthesis. These effects were dependent on Smad 2/3 pathway signaling. Finally, expression of heat shock protein 90 was increased in keloid tissue compared with control tissues. Taken together, these results demonstrate that modulation of heat shock protein 90 influences transforming growth factor-β-induced collagen synthesis via regulation of Smad 2/3 phosphorylation.

  16. Comparative Host Response of 2 Human Acellular Dermal Matrices in a Primate Implant Model

    PubMed Central

    Sandor, Maryellen; Singh, Devinder; Silverman, Ronald P.; Xu, Hui; De Deyne, Patrick G.

    2014-01-01

    Objective: We examined the differences in capsule formation between 2 commercially available human acellular dermal matrices in a nonhuman primate model. Methods: Primates were implanted dorsally with a subcutaneously placed tissue expander and randomized into 3 groups, receiving skin coverage only, coverage with non-irradiated freeze-dried human acellular dermal matrix, or coverage with gamma-irradiated human acellular dermal matrix. After 9 weeks, soft tissue around the tissue expander was excised and evaluated qualitatively and quantitatively to assess extent of inflammation (CD68 antibodies and interleukin-6 levels), degradation and fibrosis (matrix metalloproteinase-1 and procollagen-1 staining), and mechanical (tensile) strength. Results: Histological evaluation of tissue around the tissue expander indicated differences in host response, suggesting capsule presence in the gamma-irradiated matrix group but not the freeze-dried matrix group. The extent of local inflammation was much higher in the gamma-irradiated matrix group which demonstrated mean (standard deviation) localized interleukin-6 concentration of 67.3 (53.6) vs 16.3 (6.7) pg/mg protein in the non-irradiated matrix group. There was robust degradation and fibrotic response in the gamma-irradiated matrix group versus the freeze-dried matrix group. Mechanical testing indicated mean (standard deviation) ultimate tensile strength of 12.0 (7.1) N in the gamma-irradiated matrix group versus 99.3 (48.8) N in the freeze-dried matrix group. Conclusions: Enclosure of a tissue expander with human acellular dermal matrix untreated by gamma irradiation led to minimal inflammation and minimal evidence of fibrosis/capsule around the tissue expander compared with robust capsule formation around the tissue expander that was covered by a gamma-irradiated human acellular dermal matrix. PMID:24570768

  17. Evaluation of porcine dermal collagen (Permacol) used in abdominal wall reconstruction.

    PubMed

    Hsu, Patrick W; Salgado, Christopher J; Kent, Kathryn; Finnegan, Matthew; Pello, Mark; Simons, Robert; Atabek, Umur; Kann, Brian

    2009-11-01

    Various methods have been employed to reconstruct complex abdominal wall defects. Structural prosthetic materials such as polypropylene mesh and ePTFE (expanded polytetrafluoroethylene) have been widely used to close these large fascial defects, however, complications with infection and adhesions have led to the recent use of more biocompatible implants. Permacol (acellular porcine dermis) is used as a dermal scaffold, which eventually becomes vascularised and remodelled to reconstruct the abdominal wall in these complex patients. A retrospective review was performed of all patients who underwent consecutive abdominal wall reconstruction with Permacol at our institution in the year 2006. Twenty-eight patients were identified and included in our study. Factors evaluated were: body mass index, relevant co-morbidities, aetiology of hernia, hernia defect size based on CT scan and intraoperative measurement, size of Permacol implant, length of hospital stay, and postoperative complications. Surgical technique was standardised among six surgeons and involved a single layer of acellular porcine dermis as a subfascial 'underlay' graft under moderate tension upon maximal hernia reduction. Tissue expanders were not required for skin closure. Out of 28 patients, 12 were male and 16 were female. Mean intraoperative hernia size was 150 cm(2) (range of 10 cm(2) to 600 cm(2)). Mean age was 55 years with an average body mass index (BMI) of 34 (largest BMI of 61.4). Defects were attributed to either a previous laparotomy incision or open abdomen. Mean hospital stay was 9.67 days. At a mean follow-up of sixteen months, there were three recurrent hernias (10.7%) based on physical examination and postoperative CT scan evaluation. One patient developed a superficial wound dehiscence which was successfully treated with local wound care and one patient developed a cellulitis which was successfully treated with antibiotic therapy. Four patients (14.3%) developed a chronic, non

  18. Three-dimensional, multiwavelength Monte Carlo simulations of dermally implantable luminescent sensors

    NASA Astrophysics Data System (ADS)

    Long, Ruiqi; McShane, Mike

    2010-03-01

    Dermally implanted luminescent sensors have been proposed for monitoring of tissue biochemistry, which has the potential to improve treatments for conditions such as diabetes and kidney failure. Effective in vivo monitoring via noninvasive transdermal measurement of emission from injected microparticles requires a matched optoelectronic system for excitation and collection of luminescence. We applied Monte Carlo modeling to predict the characteristics of output luminescence from microparticles in skin to facilitate hardware design. Three-dimensional, multiwavelength Monte Carlo simulations were used to determine the spatial and spectral distribution of the escaping luminescence for different implantation depths, excitation light source properties, particle characteristics, and particle packing density. Results indicate that the ratio of output emission to input excitation power ranged 10-3 to 10-6 for sensors at the upper and lower dermal boundaries, respectively, and 95% of the escaping emission photons induced by a 10-mm-diam excitation beam were confined within an 18-mm circle. Tightly packed sensor configurations yielded higher output intensity with fewer particles, even after luminophore concentration effects were removed. Most importantly, for the visible wavelengths studied, the ability to measure spectral changes in emission due to glucose changes was not significantly affected by absorption and scattering of tissue, which supports the potential to accurately track changes in luminescence of sensor implants that respond to the biochemistry of the skin.

  19. Altered dermal fibroblast behavior in a collagen V haploinsufficient murine model of classic Ehlers-Danlos syndrome.

    PubMed

    DeNigris, John; Yao, Qingmei; Birk, Erika K; Birk, David E

    2016-01-01

    Mutations in collagen V are associated with classic Ehlers-Danlos syndrome (EDS). A significant percentage of these mutations result in haploinsufficiency for collagen V. The purpose of this work was to determine if changes in collagen V expression are associated with altered dermal fibroblast behavior contributing to the poor wound healing response. A haploinsufficient Col5a1(+/-) mouse model of EDS was utilized. In vivo wound healing studies demonstrated that mutant mice healed significantly slower than Col5a1(+/+) mice. The basis for this difference was examined in vitro using dermal fibroblast strains isolated from Col5a1(+/-) and Col5a1(+/+) mice. Fibroblast proliferation was determined for each strain by counting cells at different time points after seeding as well as using the proliferation marker Ki-67. Fibroblast attachment to collagens I and III and fibronectin also was analyzed. In addition, in vitro scratch wounds were used to analyze fibroblast wound closure. Significantly decreased fibroblast proliferation was observed in Col5a1(+/-) compared to Col5a1(+/+) fibroblasts. Our data indicate that the decreased fibroblast number was not due to apoptosis. Wildtype Col5a1(+/+) fibroblasts attached significantly better to components of the wound matrix (collagens I and III and fibronectin) than Col5a1(+/-) fibroblasts. A significant difference in in vitro scratch wound closure rates also was observed. Col5a1(+/+) fibroblasts closed wounds in 22 h, while Col5a1(+/-) fibroblasts demonstrated ~80% closure. There were significant differences in closure at all time points analyzed. Our data suggest that decreased fibroblast proliferation, extracellular matrix attachment, and migration contribute to the decreased wound healing response in classic EDS.

  20. Collagen implants do not preserve periodontal ligament homeostasis in periodontal wounds.

    PubMed

    Nguyen, L; Lekic, P; McCulloch, C A

    1997-07-01

    An improved understanding of the differentiation of periodontal ligament cells could facilitate the development of new treatment approaches for overcoming the loss of specialized cell types caused by periodontitis. To study healing of wounded periodontal tissues and the differentiation of mineralizing connective tissue cells in periodontal ligament, we have examined the influence of wound size and collagen implantation on the regeneration of periodontium and on immunohistochemical staining for osteopontin and bone sialoprotein. Four groups of Wistar rats were wounded by drilling through the alveolar bone and by extirpation of the periodontal ligament. Wounds were 0.6 or 1.8 mm in diameter and defects were either implanted with collagen gels or were treated without implants. Rats were killed at 1 wk or 2 months after wounding and tissue sections were stained with monoclonal antibodies against rat osteopontin and bone sialoprotein. Collagen implants strongly increased staining for osteopontin and bone sialoprotein in defects at 1 wk. By 2 months alveolar bone healed completely regardless of the wound size but in large defects, periodontal ligament width was significantly reduced with or without implants. In large wounds at 2 months, collagen implants inhibited bone regeneration and there was stronger staining for osteopontin and bone sialoprotein in the bone replacing the implant, indicating that collagen prolonged bone remodelling. We conclude that implantation of exogenous collagen affects alveolar bone healing but does not preserve the width of the regenerated periodontal ligament. Therefore collagen does not appear to contribute to homeostasis in the periodontium following wounding.

  1. Platelet adhesion and plasma protein adsorption control of collagen surfaces by He + ion implantation

    NASA Astrophysics Data System (ADS)

    Kurotobi, K.; Suzuki, Y.; Nakajima, H.; Suzuki, H.; Iwaki, M.

    2003-05-01

    He + ion implanted collagen-coated tubes with a fluence of 1 × 10 14 ions/cm 2 were exhibited antithrombogenicity. To investigate the mechanisms of antithrombogenicity of these samples, plasma protein adsorption assay and platelet adhesion experiments were performed. The adsorption of fibrinogen (Fg) and von Willebrand factor (vWf) was minimum on the He + ion implanted collagen with a fluence of 1 × 10 14 ions/cm 2. Platelet adhesion (using platelet rich plasma) was inhibited on the He + ion implanted collagen with a fluence of 1 × 10 14 ions/cm 2 and was accelerated on the untreated collagen and ion implanted collagen with fluences of 1 × 10 13, 1 × 10 15 and 1 × 10 16 ions/cm 2. Platelet activation with washed platelets was observed on untreated collagen and He + ion implanted collagen with a fluence of 1 × 10 14 ions/cm 2 and was inhibited with fluences of 1 × 10 13, 1 × 10 15 and 1 × 10 16 ions/cm 2. Generally, platelets can react with a specific ligand inside the collagen (GFOGER sequence). The results of platelets adhesion experiments using washed platelets indicated that there were no ligands such as GFOGER on the He + ion implanted collagen over a fluence of 1 × 10 13 ions/cm 2. On the 1 × 10 14 ions/cm 2 implanted collagen, no platelet activation was observed due to the influence of plasma proteins. From the above, it is concluded that the decrease of adsorbed Fg and vWf caused the antithrombogenicity of He + ion implanted collagen with a fluence of 1 × 10 14 ions/cm 2 and that plasma protein adsorption took an important role repairing the graft surface.

  2. Aging decreases collagen IV expression in vivo in the dermo-epidermal junction and in vitro in dermal fibroblasts: possible involvement of TGF-β1.

    PubMed

    Feru, Jezabel; Delobbe, Etienne; Ramont, Laurent; Brassart, Bertrand; Terryn, Christine; Dupont-Deshorgue, Aurelie; Garbar, Christian; Monboisse, Jean-Claude; Maquart, Francois-Xavier; Brassart-Pasco, Sylvie

    2016-08-01

    Collagen IV is a major component of the dermo-epidermal junction (DEJ). To study expression of collagen IV upon aging in the DEJ and dermal fibroblasts isolated from the same patients. A model of senescent fibroblasts was developed in order to identify biological compounds that might restore the level of collagen IV. Skin fragments of women (30 to 70 years old) were collected. Localisation of collagen IV expression in the DEJ was studied by immunofluorescence. Fibroblast collagen IV expression was studied by real-time PCR, ELISA, and western blotting. Premature senescence was simulated by exposing fibroblasts to subcytotoxic H2O2 concentrations. Collagen IV decreased in the DEJ and fibroblasts relative to age. TGF-β1 treatment significantly increased collagen IV gene and protein expression in fibroblasts and restored expression in the model of senescence. Addition of TGF-β1-neutralizing antibody to fibroblast cultures decreased collagen IV expression. Taken together, the results suggest that the decrease in collagen IV in the DEJ, relative to age, could be due to a decrease in collagen IV expression by senescent dermal fibroblasts and may involve TGF-β1 signalling.

  3. Influence of Aloe vera on collagen turnover in healing of dermal wounds in rats.

    PubMed

    Chithra, P; Sajithlal, G B; Chandrakasan, G

    1998-09-01

    Treatment of full-thickness wounds with A. vera, on rats resulted in increased biosynthesis of collagen and its degradation. A corresponding increase in the urinary excretion of hydroxyproline was also observed. Elevated levels of lysyl oxidase also indicated increased crosslinking of newly synthesised collagen. The results suggest that A. vera influences the wound healing process by enhancing collagen turnover in the wound tissue.

  4. Modified Lower Pole Autologous Dermal Sling for Implant Reconstruction in Women Undergoing Immediate Breast Reconstruction after Mastectomy

    PubMed Central

    2016-01-01

    Background. Autologous dermal sling with wise pattern skin reducing mastectomy allows one-stage implant reconstruction in women with large and ptotic breasts needing mastectomy for cancer or risk reduction. However, this technique is not suitable for women who lack ptosis and also carries risk of T-junction breakdown. Method. We have performed one-stage nipple sparing mastectomies with implant reconstruction in 5 women (8 breasts) by modifying the autologous dermal sling approach. All these women had small to moderate breasts with no ptosis or pseudoptosis. Results. Three women had bilateral procedures, two underwent bilateral mastectomies simultaneously, and one had contralateral risk reduction surgery a year after the cancer side operation. All women underwent direct to implant reconstruction with implant volumes varying from 320 to 375 cc. There were no implant losses and only one required further surgery to excise the nipple for positive nipple shaves. A low complication rate was encountered in this series with good aesthetic outcome. Conclusion. The modified lower pole dermal sling allows direct to implant reconstruction in selected women with small to moderate sized breasts with minimal ptosis. The approach is safe and cost-effective and results in more natural reconstruction with preservation of nipple. PMID:27800186

  5. Implantation of sepiolite-collagen complexes in surgically created rat calvaria defects.

    PubMed

    Herrera, J I; Olmo, N; Turnay, J; Sicilia, A; Bascones, A; Gavilanes, J G; Lizarbe, M A

    1995-05-01

    The response of osseous tissue to the implantation of sepiolite-collagen complexes has been studied. Sepiolite, sepiolite-collagen complex and 0.5% glutaraldehyde-treated sepiolite-collagen complex were implanted in created circular defects in rat calvaria. The tissue reactions were analysed using light, transmission and scanning electron microscopies. The patterns of bone growth were radiographically analysed and the bone activity was indirectly quantified by using a point-count method. The reaction against the three implanted materials is characteristic of a foreign body reaction with abundant macrophages and giant cells. Implanted products have been detected in macrophages, which suggest the involvement of phagocytosis in the resorptive process. Bone grew at the implantation sites originating excrescences or sometimes a thin bridge at the defect margins. The studied materials, after implantation in contact with bone tissue, did not produce any toxic effect or necrosis, allowing bone activity.

  6. Subcutaneous Implant-based Breast Reconstruction with Acellular Dermal Matrix/Mesh: A Systematic Review

    PubMed Central

    Salibian, Ara A.; Frey, Jordan D.; Choi, Mihye

    2016-01-01

    Background: The availability of acellular dermal matrix (ADM) and synthetic mesh products has prompted plastic surgeons to revisit subcutaneous implant-based breast reconstruction. The literature is limited, however, with regards to evidence on patient selection, techniques, and outcomes. Methods: A systematic review of the Medline and Cochrane databases was performed for original studies reporting breast reconstruction with ADM or mesh, and subcutaneous implant placement. Studies were analyzed for level of evidence, inclusion/exclusion criteria for subcutaneous reconstruction, reconstruction characteristics, and outcomes. Results: Six studies (186 reconstructions) were identified for review. The majority of studies (66.7%) were level IV evidence case series. Eighty percent of studies had contraindications for subcutaneous reconstruction, most commonly preoperative radiation, high body mass index, and active smoking. Forty percent of studies commenting on patient selection assessed mastectomy flap perfusion for subcutaneous reconstruction. Forty-five percent of reconstructions were direct-to-implant, 33.3% 2-stage, and 21.5% single-stage adjustable implant, with ADM utilized in 60.2% of reconstructions versus mesh. Pooled complication rates included: major infection 1.2%, seroma 2.9%, hematoma 2.3%, full nipple-areola complex necrosis 1.1%, partial nipple-areola complex necrosis 4.5%, major flap necrosis 1.8%, wound healing complication 2.3%, explantation 4.1%, and grade III/IV capsular contracture 1.2%. Conclusions: Pooled short-term complication rates in subcutaneous alloplastic breast reconstruction with ADM or mesh are low in preliminary studies with selective patient populations, though techniques and outcomes are variable across studies. Larger comparative studies and better-defined selection criteria and outcomes reporting are needed to develop appropriate indications for performing subcutaneous implant-based reconstruction. PMID:27975034

  7. Inhibition of UV-induced ROS and collagen damage by Phyllanthus emblica extract in normal human dermal fibroblasts.

    PubMed

    Majeed, Muhammed; Bhat, Beena; Anand, Susmitha; Sivakumar, A; Paliwal, Pritee; Geetha, K G

    2011-01-01

    As a part of ongoing research for novel natural cosmeceutical actives from plant extracts, this study demonstrates that Phyllanthus emblica fruit extract has shown its efficacy in protection against ultraviolet-B (UVB) irradiation-induced reactive oxygen species (ROS) and collagen damage in normal human dermal fibroblasts. At a concentration of 0.5 mg/ml, emblica extract showed a significant response of 9.5 ± 0.28-fold protection from UVB induced-collagen damage as compared to untreated cells. A known active, ascorbic acid, at a concentration of 0.5 mg/ml, showed 3.7 ± 0.07-fold protection from UVB-induced collagen damage. While the untreated cells showed 84 ± 1.4% induction in ROS on UVB irradiation as compared to the non-irradiated cells, emblica extract treatment inhibited the induction of ROS to 15 ± 4% at a concentration of 0.5 mg/ml. Ascorbic acid inhibited the induction in ROS to 64 ± 2% at a concentration of 0.5 mg/ml. Emblica extract is a significantly better natural active, with promising cosmeceutical benefits against photoaging.

  8. Influence of Aloe vera on collagen characteristics in healing dermal wounds in rats.

    PubMed

    Chithra, P; Sajithlal, G B; Chandrakasan, G

    1998-04-01

    Wound healing is a fundamental response to tissue injury that results in restoration of tissue integrity. This end is achieved mainly by the synthesis of the connective tissue matrix. Collagen is the major protein of the extracellular matrix, and is the component which ultimately contributes to wound strength. In this work, we report the influence of Aloe vera on the collagen content and its characteristics in a healing wound. It was observed that Aloe vera increased the collagen content of the granulation tissue as well as its degree of crosslinking as seen by increased aldehyde content and decreased acid solubility. The type I/type III collagen ratio of treated groups were lower than that of the untreated controls, indicating enhanced levels of type III collagen. Wounds were treated either by topical application or oral administration of Aloe vera to rats and both treatments were found to result in similar effects.

  9. Plasma mediated collagen-I-coating of metal implant materials to improve biocompatibility.

    PubMed

    Hauser, Joerg; Koeller, Manfred; Bensch, Sebastian; Halfmann, Helmut; Awakowicz, Peter; Steinau, Hans-Ulrich; Esenwein, Stefan

    2010-07-01

    This study describes the collagen-I coating of titanium and steel implants via cold low-pressure gas plasma treatment. To analyze the coatings in terms of biocompatibility osteoblast-like osteosarcoma cells and human leukocytes were cultivated on the metal surfaces. Two different implant materials were assessed (Ti6Al4V, X2CrNiMo18) and four different surface properties were evaluated: (a) plasma pretreated and collagen-I coated implant materials; (b) collagen-I dip-coated without plasma pretreatment; (c) plasma treated but not collagen-I coated; (d) standard implant materials served as control. The different coating characteristics were analyzed by scanning electron microscopy (SEM). For adhesion and viability tests calcein-AM staining of the cells and Alamar blue assays were performed. The quantitative analysis was conducted by computer assisted microfluorophotography and spectrometer measurements. SEM analysis revealed that stable collagen-I coatings could not be achieved on the dip-coated steel and titanium alloys. Only due to pretreatment with low-pressure gas plasma a robust deposition of collagen I on the surface could be achieved. The cell viability and cell attachment rate on the plasma pretreated, collagen coated surfaces was significantly (p < 0.017) increased compared to the non coated surfaces. Gas plasma treatment is a feasible method for the deposition of proteins on metal implant materials resulting in an improved biocompatibility in vitro. (c) 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010.

  10. Chum salmon egg extracts induce upregulation of collagen type I and exert antioxidative effects on human dermal fibroblast cultures

    PubMed Central

    Yoshino, Atsushi; Polouliakh, Natalia; Meguro, Akira; Takeuchi, Masaki; Kawagoe, Tatsukata; Mizuki, Nobuhisa

    2016-01-01

    Components of fish roe possess antioxidant and antiaging activities, making them potentially very beneficial natural resources. Here, we investigated chum salmon eggs (CSEs) as a source of active ingredients, including vitamins, unsaturated fatty acids, and proteins. We incubated human dermal fibroblast cultures for 48 hours with high and low concentrations of CSE extracts and analyzed changes in gene expression. Cells treated with CSE extract showed concentration-dependent upregulation of collagen type I genes and of multiple antioxidative genes, including OXR1, TXNRD1, and PRDX family genes. We further conducted in silico phylogenetic footprinting analysis of promoter regions. These results suggested that transcription factors such as acute myeloid leukemia-1a and cyclic adenosine monophosphate response element-binding protein may be involved in the observed upregulation of antioxidative genes. Our results support the idea that CSEs are strong candidate sources of antioxidant materials and cosmeceutically effective ingredients. PMID:27621603

  11. Chum salmon egg extracts induce upregulation of collagen type I and exert antioxidative effects on human dermal fibroblast cultures.

    PubMed

    Yoshino, Atsushi; Polouliakh, Natalia; Meguro, Akira; Takeuchi, Masaki; Kawagoe, Tatsukata; Mizuki, Nobuhisa

    2016-01-01

    Components of fish roe possess antioxidant and antiaging activities, making them potentially very beneficial natural resources. Here, we investigated chum salmon eggs (CSEs) as a source of active ingredients, including vitamins, unsaturated fatty acids, and proteins. We incubated human dermal fibroblast cultures for 48 hours with high and low concentrations of CSE extracts and analyzed changes in gene expression. Cells treated with CSE extract showed concentration-dependent upregulation of collagen type I genes and of multiple antioxidative genes, including OXR1, TXNRD1, and PRDX family genes. We further conducted in silico phylogenetic footprinting analysis of promoter regions. These results suggested that transcription factors such as acute myeloid leukemia-1a and cyclic adenosine monophosphate response element-binding protein may be involved in the observed upregulation of antioxidative genes. Our results support the idea that CSEs are strong candidate sources of antioxidant materials and cosmeceutically effective ingredients.

  12. Induction of cartilage integration by a chondrocyte/collagen-scaffold implant.

    PubMed

    Pabbruwe, Moreica B; Esfandiari, Ehsanollah; Kafienah, Wael; Tarlton, John F; Hollander, Anthony P

    2009-09-01

    The integration of implanted cartilage is a major challenge for the success of tissue engineering protocols. We hypothesize that in order for effective cartilage integration to take place, matrix-free chondrocytes must be induced to migrate between the two tissue surfaces. A chondrocyte/collagen-scaffold implant system was developed as a method of delivering dividing cells at the interface between two cartilage surfaces. Chondrocytes were isolated from bovine nasal septum and seeded onto both surfaces of a collagen membrane to create the chondrocyte/collagen-scaffold implant. A model of two cartilage discs and the chondrocyte/collagen-scaffold sandwiched in between was used to effect integration in vitro. The resulting tissue was analysed histologically and biomechanically. The cartilage-implant-cartilage sandwich appeared macroscopically as one continuous piece of tissue at the end of 40 day cultures. Histological analysis showed tissue continuum across the cartilage-scaffold interface. The integration was dependent on both cells and scaffold. Fluorescent labeling of implanted chondrocytes demonstrated that these cells invade the surrounding mature tissue and drive a remodelling of the extracellular matrix. Using cell-free scaffolds we also demonstrated that some chondrocytes migrated from the natural cartilage into the collagen scaffold. Quantification of integration levels using a histomorphometric repair index showed that the chondrocyte/collagen-scaffold implant achieved the highest repair index compared to controls, reflected functionally through increased tensile strength. In conclusion, cartilage integration can be achieved using a chondrocyte/collagen-scaffold implant that permits controlled delivery of chondrocytes to both host and graft mature cartilage tissues. This approach has the potential to be used therapeutically for implantation of engineered tissue.

  13. Dermal fibroblasts participate in the formation of new muscle fibres when implanted into regenerating normal mouse muscle.

    PubMed

    Pye, D; Watt, D J

    2001-02-01

    Both in vitro and in vivo studies have described the conversion of fibroblasts to myogenesis when in the presence of dysfunctional myogenic cells. Myogenic conversion of fibroblasts subjected to a normal, as opposed to a diseased muscle environment has only been reported in vitro. The primary aim of this work was to determine if fibroblasts can convert to a myogenic lineage and contribute to new fibre formation when implanted into the regenerating muscle of a normal mouse. Dermal fibroblasts were prepared from neonatal mouse skin and labelled prior to implantation with the fluorescent nuclear marker 4',6-diamidino-2-phenylindole (DAPI). Cells were implanted into muscles of host mice that had been subjected to either cold/crush or minced muscle injury. Some host muscles were x-irradiated to deplete the muscle of endogenous muscle precursor cells. Muscles were removed at 3 wk postimplantation and analysed both histologically and for the presence of DAPI labelled nuclei. Fibres containing DAPI labelled central nuclei indicated that the implanted cells had participated in the regenerative process. Mouse dermal fibroblasts therefore do contribute to muscle fibre formation in regenerating normal mouse muscle but the extent of their contribution is dependent on the nature of the trauma induced in the host muscle. The study also showed that regeneration was more successful in muscles which had not been irradiated, which is contrary to the previous studies where dermal fibroblasts were introduced into myopathic mouse muscle.

  14. Dermal fibroblasts participate in the formation of new muscle fibres when implanted into regenerating normal mouse muscle

    PubMed Central

    PYE, DEBORAH; WATT, DIANA J.

    2001-01-01

    Both in vitro and in vivo studies have described the conversion of fibroblasts to myogenesis when in the presence of dysfunctional myogenic cells. Myogenic conversion of fibroblasts subjected to a normal, as opposed to a diseased muscle environment has only been reported in vitro. The primary aim of this work was to determine if fibroblasts can convert to a myogenic lineage and contribute to new fibre formation when implanted into the regenerating muscle of a normal mouse. Dermal fibroblasts were prepared from neonatal mouse skin and labelled prior to implantation with the fluorescent nuclear marker 4′,6-diamidino-2-phenylindole (DAPI). Cells were implanted into muscles of host mice that had been subjected to either cold/crush or minced muscle injury. Some host muscles were x-irradiated to deplete the muscle of endogenous muscle precursor cells. Muscles were removed at 3 wk postimplantation and analysed both histologically and for the presence of DAPI labelled nuclei. Fibres containing DAPI labelled central nuclei indicated that the implanted cells had participated in the regenerative process. Mouse dermal fibroblasts therefore do contribute to muscle fibre formation in regenerating normal mouse muscle but the extent of their contribution is dependent on the nature of the trauma induced in the host muscle. The study also showed that regeneration was more successful in muscles which had not been irradiated, which is contrary to the previous studies where dermal fibroblasts were introduced into myopathic mouse muscle. PMID:11273041

  15. Regulation of collagen synthesis in human dermal fibroblasts by ascorbic-induced lipid peroxidation

    SciTech Connect

    Geesin, J.C. Johnson and Johnson Consumer Products, Inc., Skillman, NJ ); Gordon, J.S. ); Gordon, J.S. ); Berg, R.A. )

    1991-03-11

    Ascorbic acid has been shown to stimulate collagen synthesis through the induction of lipid peroxidation which leads to increased transcription of the collagen genes. To test the ability of aldehyde products of lipid peroxidation to mediate this effect, the authors treated cultured fibroblasts with 1-200{mu}M of malondialdehyde, acetaldehyde, glyoxal or hexenal in the presence of lipid peroxidation inducing or noninducing concentrations of ascorbic acid. The treatment process involved either pretreatment of cells for 66hrs with either concentration of ascorbate before a 6hr treatment in the presence of ascorbate and the aldehydes, or 6 or 72hr treatment of the cells in the presence of either concentration of ascorbate plus the aldehydes. No effect of any of these aldehydes was seen on ascorbate-stimulated collagen synthesis. Also, pretreatment of fibroblasts for 24hrs with 100nM phorbol myristate acetate (PMA), which produces down regulation of protein kinase C(PKC), failed to alter the ascorbate-stimulation of collagen synthesis. Additionally, the authors tested the ability of benzamide, a poly ACP ribosylation inhibitor, to inhibit the ascorbate response with no specific effect noted. These results do not support the proposed roles for aldehydes, PKC, or poly ADP ribosylation in the mediation of the lipid peroxidation induced stimulation of collagen synthesis.

  16. Capsular contracture in implant based breast reconstruction—the effect of porcine acellular dermal matrix

    PubMed Central

    Ho-Asjoe, Mark; Junge, Klaus; Farhadi, Jian

    2017-01-01

    Background Irradiation of implant-based breast reconstructions (BR) is known to increase capsular contracture (CC) rates on average by 4-fold over non-irradiated reconstructions. The use of acellular dermal matrix (ADM) has been associated with lower CC rates in non-irradiated reconstructions (0-3%). Experimental and clinical studies suggest that ADM may also reduce CC rates in irradiated breasts. The aim of this study was to evaluate CC rates in non-irradiated and irradiated one- and two-stage BRs performed with the assistance of porcine ADM (PADM). Methods A single centre, retrospective, cohort study was designed from December 2008 to October 2012. A total of 200 immediate implant-based BRs were performed using PADM for inferior pole reinforcement. We included non-irradiated BR with a minimum follow up of 6 month from primary surgery (one stage) or from explantation of expander and implantation of the definitive implant (two stage). Of the postoperatively irradiated BR we included patients with 1 year or more follow up time from termination of radiotherapy. CC was graded using the conventional Spear-Baker classification and modified version for irradiated BR. According to the literature Grade III and IV CC were defined as clinically significant CC. Results Of 200 BRs with PADM, 122 were included in this study (84 non-irradiated and 38 irradiated). Sixty-five BR were one stage and 57 were two stage BR. Grade III/IV CC was remarkable low in non-irradiated (6%) and irradiated BR (13%). There was a non-significant trend to increased Grade III and IV CC in irradiated BR vs. non-irradiated BR (13% vs. 6%, P=0.216). In this study follow up time (P<0.001) and the stage of ADM reconstruction (two vs. one stage, P=0.022) were significant risk factors for occurrence of grade III/IV CC on univariate analysis and remained significant for the follow up time (P=0.013) and remarkable for the stages (P=0.093) in multivariate analysis. Conclusions Our data support the current

  17. Induction of cartilage integration by a chondrocyte/collagen-scaffold implant

    PubMed Central

    Pabbruwe, Moreica B.; Esfandiari, Ehsanollah; Kafienah, Wael; Tarlton, John F.; Hollander, Anthony P.

    2009-01-01

    The integration of implanted cartilage is a major challenge for the success of tissue engineering protocols. We hypothesize that in order for effective cartilage integration to take place, matrix-free chondrocytes must be induced to migrate between the two tissue surfaces. A chondrocyte/collagen-scaffold implant system was developed as a method of delivering dividing cells at the interface between two cartilage surfaces. Chondrocytes were isolated from bovine nasal septum and seeded onto both surfaces of a collagen membrane to create the chondrocyte/collagen-scaffold implant. A model of two cartilage discs and the chondrocyte/collagen-scaffold sandwiched in between was used to effect integration in vitro. The resulting tissue was analysed histologically and biomechanically. The cartilage–implant–cartilage sandwich appeared macroscopically as one continuous piece of tissue at the end of 40 day cultures. Histological analysis showed tissue continuum across the cartilage–scaffold interface. The integration was dependent on both cells and scaffold. Fluorescent labeling of implanted chondrocytes demonstrated that these cells invade the surrounding mature tissue and drive a remodelling of the extracellular matrix. Using cell-free scaffolds we also demonstrated that some chondrocytes migrated from the natural cartilage into the collagen scaffold. Quantification of integration levels using a histomorphometric repair index showed that the chondrocyte/collagen-scaffold implant achieved the highest repair index compared to controls, reflected functionally through increased tensile strength. In conclusion, cartilage integration can be achieved using a chondrocyte/collagen-scaffold implant that permits controlled delivery of chondrocytes to both host and graft mature cartilage tissues. This approach has the potential to be used therapeutically for implantation of engineered tissue. PMID:19539365

  18. Peri-implant collagen fibers around human cone Morse connection implants under polarized light: a report of three cases.

    PubMed

    Degidi, Marco; Piattelli, Adriano; Scarano, Antonio; Shibli, Jamil A; Iezzi, Giovanna

    2012-06-01

    Most of the histologic studies found in the literature on the peri-implant soft tissues have been done in animals and usually have been confined to mandibular implants fitted with healing or standard abutments. Few studies have investigated human peri-implant soft tissues. Moreover, the structure and dimensions of the peri-implant soft tissues in immediately loaded implants have not been investigated in depth. Human histologic data are valuable to validate animal models. This histologic and histomorphometric study evaluated the peri-implant soft tissues around three immediately loaded implants in humans. The implants were retrieved using a trephine and treated to obtain thin, ground sections. The sulcular epithelium was composed of approximately four to five layers of parakeratinized epithelial cells and had a length of approximately 1.2 to 1.3 mm. The junctional epithelium was composed of approximately three to four layers of epithelial cells and had a length of approximately 1.0 to 1.5 mm. Connective tissue attachment had a width of between 400 and 800 μm. Peri-implant collagen fibers, in the form of bundles (1- to 5-μm thick), began at the crestal bone and were oriented perpendicular to the abutment surface until 200 μm from the surface, where they became parallel running in several directions. Collagen fibers appeared to form a three-dimensional network around the abutment. No acute or chronic inflammatory cell infiltrate was present. Collagen fibers oriented in a perpendicular manner and in direct contact with the abutment surface were not observed in any of the specimens. This differentiated network of fibers may have clinical relevance as a mechanical protection of the underlying bone. These human histologic data are extremely valuable to validate and confirm those obtained from studies performed on animal models. Moreover, immediate loading of the implants did not compromise soft tissue integration.

  19. Effects of Gadodiamide on cell proliferation and collagen production in cultured human dermal fibroblasts.

    PubMed

    Ozawa, Yumi; Hayashi, Shujiro; Hamasaki, Yoichiro; Hatamochi, Atsushi

    2016-12-01

    Nephrogenic systemic fibrosis (NSF) is a disease characterized by fibrosis of the systemic organs in patients with renal failure. Following the findings of recent epidemiological studies and the finding of gadolinium (Gd) in the skin tissue of NSF patients, it is now definitely known that the use of Gd contrast agents can trigger NSF. To date, however, the exact mechanism underlying the induction of fibrosis in various organs by Gd remains unexplained. This study was undertaken to evaluate the influence of Gd on the proliferation activity and collagen production of cultured fibroblasts. Normal human dermis-derived fibroblasts were incubated in the presence of gadodiamide (GA) in the concentration range of 5 × 10(-7) to 5 × 10(-3) M. The proliferation activity of the cells was assessed on the basis of the cell counts in the fibroblast growth curve and the DNA-synthetic activity of the cells (indicator; level of (3)H-thymidine uptake by cells). The collagen production was evaluated by densitometric measurement of the quantity of collagen through electrophoresis and fluorography after incorporation of (3)H-proline into the procollagens. Furthermore, the expression levels of the genes for type I and III collagen were measured by real-time reverse transcription polymerase chain reaction (RT-PCR) assay. The cell count tended to be higher when the fibroblasts were incubated in medium containing GA in the concentration range of 5 × 10(-7) to 5 × 10(-4)M as compared to that in the GA-free control cultures; furthermore, the DNA-synthetic activity also rose in a concentration-dependent manner in the GA-treated group as compared to that in the control group. No significant changes in either the collagen production or the collagen gene expression levels were noted in cultures containing GA at concentrations between 5 × 10(-7) and 5 × 10(-3) M. These results suggest that the formation of sclerosing lesions in patients with NSF may be attributable to the effect

  20. Surface engineering of stainless steel materials by covalent collagen immobilization to improve implant biocompatibility.

    PubMed

    Müller, Rainer; Abke, Jochen; Schnell, Edith; Macionczyk, Frank; Gbureck, Uwe; Mehrl, Robert; Ruszczak, Zbigniev; Kujat, Richard; Englert, Carsten; Nerlich, Michael; Angele, Peter

    2005-12-01

    It was shown recently that the deposition of thin films of tantalum and tantalum oxide enhanced the long-term biocompatibility of stainless steel biomaterials due to an increase in their corrosion resistance. In this study, we used this tantalum oxide coating as a basis for covalent immobilization of a collagen layer, which should result in a further improvement of implant tissue integration. Because of the high degradation rate of natural collagen in vivo, covalent immobilization as well as carbodiimide induced cross-linking of the protein was performed. It was found that the combination of the silane-coupling agent aminopropyl triethoxysilane and the linker molecule N,N'-disulphosuccinimidyl suberate was a very effective system for collagen immobilizing. Mechanical and enzymatic stability testing revealed a higher stability of covalent bound collagen layers compared to physically adsorbed collagen layers. The biological response induced by the surface modifications was evaluated by in vitro cell culture with human mesenchymal stem cells as well as by in vivo subcutaneous implantation into nude mice. The presence of collagen clearly improved the cytocompatibility of the stainless steel implants which, nevertheless, significantly depended on the cross-linking degree of the collagen layer.

  1. Comparative analysis of collagen membranes for the treatment of implant dehiscence defects.

    PubMed

    Oh, Tae-Ju; Meraw, Stephen J; Lee, Eun-Ju; Giannobile, William V; Wang, Hom-Lay

    2003-02-01

    Guided bone regeneration (GBR) evolved from the concept of guided tissue regeneration (GTR) and has been used for reconstructing sites with bone deficiencies associated with dental implants. For GBR, the use of absorbable collagen membranes has been increasing, but, at present, scientific information on the use of collagen membranes for GBR is limited. This study was aimed to clinically and histomorphometrically compare two collagen membranes, Bio-Gide(R) and BioMend ExtendTM, for the treatment of implant dehiscence defects in eight mongrel dogs. Implant dehiscence defects were surgically created in edentulous ridges, followed by the placement of three endosseous implants bilaterally in the mandible. Each implant dehiscence defect was randomly assigned to one of three treatment groups: (1) control (no membrane), (2) porcine dermis collagen barrier (Bio-Gide) or (3) bovine tendon collagen barrier (BioMend Extend). Dogs were sacrificed at 4 and 16 weeks (four dogs each) after treatment. Histomorphometric analysis included percentage linear bone fill (LF), new bone-to-implant contact (BIC) and area of new bone fill (BF). The results of the study revealed no significant differences among groups for any parameter at 4 weeks. However, at 16 weeks, more LF, BIC, and BF were noted in the membrane-treated groups than controls. BioMend Extend-treated defects demonstrated significantly greater BIC than control (P < 0.05) at this time point. BIC at 16 weeks was significantly greater than 4-week BIC (P < 0.05). Membrane exposure occurred in 9 out of 15 sites examined, resulting in significantly less LF and BIC than the sites without membrane exposure (P < 0.05). The results of this study indicate that: (1) GBR treatment with collagen membranes may significantly enhance bone regeneration, manifested at late stage (16 weeks) of healing; and (2) space maintenance and membrane coverage were the two most important factors affecting GBR using bioabsorbable collagen membranes.

  2. Oxidant exposure induces cysteine-rich protein 61 (CCN1) via c-Jun/AP-1 to reduce collagen expression in human dermal fibroblasts.

    PubMed

    Qin, Zhaoping; Robichaud, Patrick; He, Tianyuan; Fisher, Gary J; Voorhees, John J; Quan, Taihao

    2014-01-01

    Human skin is a primary target of oxidative stress from reactive oxygen species (ROS) generated from both extrinsic and intrinsic sources. Oxidative stress inhibits the production of collagen, the most abundant protein in skin, and thus contributes to connective tissue aging. Here we report that cysteine-rich protein 61 (CCN1), a negative regulator of collagen production, is markedly induced by ROS and mediates loss of type I collagen in human dermal fibroblasts. Conversely, antioxidant N-acetyl-L-cysteine significantly reduced CCN1 expression and prevented ROS-induced loss of type I collagen in both human dermal fibroblasts and human skin in vivo. ROS increased c-Jun, a critical member of transcription factor AP-1 complex, and increased c-Jun binding to the AP-1 site of the CCN1 promoter. Functional blocking of c-Jun significantly reduced CCN1 promoter and gene expression and thus prevented ROS-induced loss of type I collagen. Targeting the c-Jun/CCN1 axis may provide clinical benefit for connective tissue aging in human skin.

  3. Oxidant Exposure Induces Cysteine-Rich Protein 61 (CCN1) via c-Jun/AP-1 to Reduce Collagen Expression in Human Dermal Fibroblasts

    PubMed Central

    Qin, Zhaoping; Robichaud, Patrick; He, Tianyuan; Fisher, Gary J.; Voorhees, John J.; Quan, Taihao

    2014-01-01

    Human skin is a primary target of oxidative stress from reactive oxygen species (ROS) generated from both extrinsic and intrinsic sources. Oxidative stress inhibits the production of collagen, the most abundant protein in skin, and thus contributes to connective tissue aging. Here we report that cysteine-rich protein 61 (CCN1), a negative regulator of collagen production, is markedly induced by ROS and mediates loss of type I collagen in human dermal fibroblasts. Conversely, antioxidant N-acetyl-L-cysteine significantly reduced CCN1 expression and prevented ROS-induced loss of type I collagen in both human dermal fibroblasts and human skin in vivo. ROS increased c-Jun, a critical member of transcription factor AP-1 complex, and increased c-Jun binding to the AP-1 site of the CCN1 promoter. Functional blocking of c-Jun significantly reduced CCN1 promoter and gene expression and thus prevented ROS-induced loss of type I collagen. Targeting the c-Jun/CCN1 axis may provide clinical benefit for connective tissue aging in human skin. PMID:25536346

  4. Osteogenicity of titanium implants coated with calcium phosphate or collagen type-I in osteoporotic rats.

    PubMed

    Alghamdi, Hamdan S; Bosco, Ruggero; van den Beucken, Jeroen J J P; Walboomers, X Frank; Jansen, John A

    2013-05-01

    This study hypothesized that modification of titanium implant surface, e.g. by the deposition of inorganic/organic coatings, can significantly improve the implant-bone response compared in osteoporotic vs. healthy conditions. After osteoporosis was induced in 15 female Wistar rats by ovariectomy (OVX) and confirmed by in vivo micro-CT analysis, implants coated with calcium phosphate (CaP) or collagen type-I and non-coated implants were placed into bilateral femoral condyles. Another 15 sham-operated rats served as controls. Twelve weeks after implantation, micro-CT bone volume (%BV) and histomorphometrical bone area (%BA) were lower around control implants in osteoporotic rats (BV = 60.4%, BA = 43.8%) compared to sham-operated rats (BV = 74.0%, BA = 62.0%). Interestingly, CaP and collagen type-I surface coatings enhanced bone-to-implant contact (%BIC) compared to non-coated implants in osteoporosis (51.9%, 58.2%) as well as in sham-operated (69.7%, 64.4%) groups. The study confirmed that an osteoporotic condition has a significant effect on the amount of bone present in close vicinity to implants. Evidently, the use of osteogenic surface coatings has a favorable effect on the bone implant interface in both osteoporotic and sham-operated conditions.

  5. Direct Hospital Cost of Outcome Pathways in Implant-Based Reconstruction with Acellular Dermal Matrices

    PubMed Central

    Qureshi, Ali A.; Broderick, Kristen; Funk, Susan; Reaven, Nancy; Tenenbaum, Marissa M.

    2016-01-01

    Background: Current cost data on tissue expansion followed by exchange for permanent implant (TE/I) reconstruction lack a necessary assessment of the experience of a heterogenous breast cancer patient population and their multiple outcome pathways. We extend our previous analysis to that of direct hospital cost as bundling of payments is likely to follow the changing centralization of cancer care at the hospital level. Methods: We performed a retrospective analysis (2003–2009) of TE/I reconstructions with or without an acellular dermal matrix (ADM), namely Alloderm RTM. Postreconstructive events were analyzed and organized into outcome pathways as previously described. Aggregated and normalized inpatient and outpatient hospital direct costs and physician reimbursement were generated for each outcome pathway with or without ADM. Results: Three hundred sixty-seven patients were analyzed. The average 2-year hospital direct cost per TE/I breast reconstruction patient was $11,862 in the +ADM and $12,319 in the −ADM groups (P > 0.05). Initial reconstructions were costlier in the +ADM ($6,868) than in the −ADM ($5,615) group, but the average cost of subsequent postreconstructive events within 2 years was significantly lower in +ADM ($5,176) than −ADM ($6,704) patients (P < 0.05). When a complication occurred, but reconstruction was still completed within 2 years, greater costs were incurred in the −ADM than in the +ADM group for most scenarios, leading to a net equalization of cost between study groups. Conclusion: Although direct hospital cost is an important factor for resource and fund allocation, it should not remain the sole factor when deciding to use ADM in TE/I reconstruction. PMID:27622099

  6. Pyropia yezoensis peptide promotes collagen synthesis by activating the TGF-β/Smad signaling pathway in the human dermal fibroblast cell line Hs27

    PubMed Central

    Kim, Cho-Rong; Kim, Young-Min; Lee, Min-Kyeong; Kim, In-Hye; Choi, Youn-Hee; Nam, Taek-Jeong

    2017-01-01

    Pyropia yezoensis (P. yezoensis) is a marine algae that exhibits antioxidant, anti-inflammatory, antitumor and anti-aging activities. In this study, we investigated the effects of the P. yezoensis peptide, PYP1-5, on collagen synthesis in the human dermal fibroblast cell line Hs27. Skin aging is related to reduced collagen production and the activities of multiple enzymes, including matrix metalloproteinases (MMPs), which degrade collagen structure in the dermis, and tissue inhibitor of tissue inhibitor of metalloproteinases (TIMPs), which inhibit the action of MMPs. While collagen synthesis is associated with a number of signaling pathways, we examined the increased collagen synthesis via the upregulation of the transforming growth factor-β (TGF-β)/Smad signaling pathway. Using MTS assay, we found that PYP1-5 did not affect cell viability. Moreover, we confirmed that PYP1-5 increased type 1 collagen expression using enzyme-linked immunosorbent assay (ELISA), western blot analysis and quantitative PCR. In addition, we identified changes in various enzymes, as well as the mechanisms behind the PYP1-5-induced collagen synthesis. PYP1-5 decreased the MMP-1 protein and mRNA levels, and increased the TIMP-1 and TIMP-2 protein and mRNA levels. In addition, PYP1-5 activated the TGF-β/Smad signaling pathway, which increased TGF-β1, p-Smad2 and p-Smad3 expression, while inhibiting Smad7, an inhibitor of the TGF-β/Smad pathway. Furthermore, PYP1-5 upregulated transcription factor specificity protein 1 (Sp1) expression, which is reportedly involved in type 1 collagen expression. These findings indicate that PYP1-5 activates the TGF-β/Smad signaling pathway, which subsequently induces collagen synthesis in Hs27 cells. PMID:27878236

  7. Dermal Stability and In Vitro Skin Permeation of Collagen Pentapeptides (KTTKS and palmitoyl-KTTKS)

    PubMed Central

    Choi, Yun Lim; Park, Eun Ji; Kim, Eunje; Na, Dong Hee; Shin, Young-Hee

    2014-01-01

    Collagen pentapeptide (Lys-Thr-Thr-Lys-Ser, KTTKS) and its palmitoylated derivative (pal-KTTKS) have received a great deal of attention as cosmeceutical ingredients for their anti-wrinkle effects. The objective of this study was to evaluate stability and permeability of KTTKS and pal-KTTKS in hairless mouse skin. In this study, a liquid chromatography-tandem mass spectrometric method was developed for the quantification of pal-KTTKS, and used for stability and permeability studies. Stability studies were performed using skin extracts and homogenates. Both KTTKS and pal-KTTKS were rapidly degraded, but pal-KTTKS was more stable than KTTKS. When protease inhibitors were added, the stability of both compounds (KTTKS and pal-KTTKS) improved significantly. In the skin permeation study, neither KTTKS nor pal-KTTKS was detected in the receptor solution, which indicates that neither compound could permeate through the full-thickness hairless mouse skin in the experimental conditions of this study. While KTTKS was not detected in any of the skin layers (the stratum corneum, epidermis, and dermis), pal-KTTKS was observed in all skin layers: 4.2 ± 0.7 μg/cm2 in the stratum corneum, 2.8 ± 0.5 μg/cm2 in the epidermis, and 0.3 ± 0.1 μg/cm2 in the dermis. In conclusion, this study indicated that pal-KTTKS had greater stability and permeability than that of un-modified KTTKS, and may be a useful anti-wrinkle and anti-aging cosmeceutical agent. PMID:25143811

  8. The Effect of Sterile Acellular Dermal Matrix Use on Complication Rates in Implant-Based Immediate Breast Reconstructions

    PubMed Central

    Park, Youngsoo; Choi, Kyoung Wook; Chung, Kyu-Jin; Kim, Tae Gon; Kim, Yong-Ha

    2016-01-01

    Background The use of acellular dermal matrix (ADM) in implant-based immediate breast reconstruction has been increasing. The current ADMs available for breast reconstruction are offered as aseptic or sterile. No published studies have compared aseptic and sterile ADM in implant-based immediate breast reconstruction. The authors performed a retrospective study to evaluate the outcomes of aseptic versus sterile ADM in implant-based immediate breast reconstruction. Methods Implant-based immediate breast reconstructions with ADM conducted between April 2013 and January 2016 were included. The patients were divided into 2 groups: the aseptic ADM (AlloDerm) group and the sterile ADM (MegaDerm) group. Archived records were reviewed for demographic data and postoperative complication types and frequencies. The complications included were infection, flap necrosis, capsular contracture, seroma, hematoma, and explantation for any cause. Results Twenty patients were reconstructed with aseptic ADM, and 68 patients with sterile ADM. Rates of infection (15.0% vs. 10.3%), flap necrosis (5.0% vs. 7.4%), capsular contracture (20.0% vs. 14.7%), seroma (10.0% vs. 14.7%), hematoma (0% vs. 1.5%), and explantation (10.0% vs. 8.8%) were not significantly different in the 2 groups. Conclusions Sterile ADM did not provide better results regarding infectious complications than aseptic ADM in implant-based immediate breast reconstruction. PMID:27896182

  9. A titanium surface with nano-ordered spikes and pores enhances human dermal fibroblastic extracellular matrix production and integration of collagen fibers.

    PubMed

    Yamada, Masahiro; Kato, Eiji; Yamamoto, Akiko; Sakurai, Kaoru

    2016-02-02

    The acquisition of substantial dermal sealing determines the prognosis of percutaneous titanium-based medical devices or prostheses. A nano-topographic titanium surface with ordered nano-spikes and pores has been shown to induce periodontal-like connective tissue attachment and activate gingival fibroblastic functions. This in vitro study aimed to determine whether an alkali-heat (AH) treatment-created nano-topographic titanium surface could enhance human dermal fibroblastic functions and binding strength to the deposited collagen on the titanium surface. The surface topographies of commercially pure titanium machined discs exposed to two different AH treatments were evaluated. Human dermal fibroblastic cultures grown on the discs were evaluated in terms of cellular morphology, proliferation, extracellular matrix (ECM) and proinflammatory cytokine synthesis, and physicochemical binding strength of surface-deposited collagen. An isotropically-patterned, shaggy nano-topography with a sponge-like inner network and numerous well-organized, anisotropically-patterned fine nano-spikes and pores were observed on each nano-topographic surface type via scanning electron microscopy. In contrast to the typical spindle-shaped cells on the machined surfaces, the isotropically- and anisotropically-patterned nano-topographic titanium surfaces had small circular/angular cells containing contractile ring-like structures and elongated, multi-shaped cells with a developed cytoskeletal network and multiple filopodia and lamellipodia, respectively. These nano-topographic surfaces enhanced dermal-related ECM synthesis at both the protein and gene levels, without proinflammatory cytokine synthesis or reduced proliferative activity. Deposited collagen fibers were included in these surfaces and sufficiently bound to the nano-topographies to resist the physical, enzymatic and chemical detachment treatments, in contrast to machined surfaces. Well-organized, isotropically

  10. Percutaneous Implants with Porous Titanium Dermal Barriers: An In Vivo Evaluation of Infection Risk

    PubMed Central

    Isackson, Dorthyann; McGill, Lawrence D.; Bachus, Kent N.

    2010-01-01

    Osseointegrated percutaneous implants are a promising prosthetic alternative for a subset of amputees. However, as with all percutaneous implants, they have an increased risk of infection since they breach the skin barrier. Theoretically, host tissues could attach to the metal implant creating a barrier to infection. When compared with smooth surfaces, it is hypothesized that porous surfaces improve the attachment of the host tissues to the implant, and decrease the infection risk. In this study, 4 titanium implants, manufactured with a percutaneous post and a subcutaneous disk, were placed subcutaneously on the dorsum of eight New Zealand White rabbits. Beginning at four weeks post-op, the implants were inoculated weekly with 108 CFU Staphylococcus aureus until signs of clinical infection presented. While we were unable to detect a difference in the incidence of infection of the porous metal implants, smooth surface (no porous coating) percutaneous and subcutaneous components had a 7-fold increased risk of infection compared to the implants with a porous coating on one or both components. The porous coated implants displayed excellent tissue ingrowth into the porous structures; whereas, the smooth implants were surrounded with a thick, organized fibrotic capsule that was separated from the implant surface. This study suggests that porous coated metal percutaneous implants are at a significantly lower risk of infection when compared to smooth metal implants. The smooth surface percutaneous implants were inadequate in allowing a long-term seal to develop with the soft tissue, thus increasing vulnerability to the migration of infecting microorganisms. PMID:21145778

  11. Characterization of a non-fibrillar-related collagen in the mollusc Haliotis tuberculata and its biological activity on human dermal fibroblasts.

    PubMed

    Fleury, Christophe; Serpentini, Antoine; Kypriotou, Magdalini; Renard, Emmanuelle; Galéra, Philippe; Lebel, Jean-Marc

    2011-10-01

    In invertebrates, members of the collagen family have been found in various phyla. Surprisingly, in mollusc, little is known about such molecules. In this study, we characterize the full-length abalone type IV collagen and we analysed its biological effects on human fibroblast in order to gain insights about this molecule in molluscs and particularly clues about its roles. We screened a cDNA library of Haliotis tuberculata hemocytes. The expression pattern of the transcript is determined using real-time polymerase chain reaction and in situ hybridization. The close identity between α1(IV) C-terminal domain and the vertebrate homologue led us to produce, purify and test in vitro a recombinant protein corresponding to this region using human dermal fibroblasts cell culture. The biological effects were evaluated on proliferation and on differentiation. We found that the 5,334-bp open reading frame transcript encodes a protein of 1,777 amino acids, including an interrupted 1,502-residue collagenous domain and a 232-residue C-terminal non-collagenous domain. The expression pattern of this transcript is mainly found in the mantle and hemocytes. The recombinant protein corresponding α1(IV) C-terminal domain increased fibroblast proliferation by 69% and doubled collagen synthesis produced in primary cultures. This work provides the first complete primary structure of a mollusc non-fibrillar collagen chain and the biological effects of its C-terminal domain on human cells. In this study, we prove that the NC1 domain from a molluscan collagen can improve human fibroblast proliferation as well as differentiation.

  12. [Implantation of collagen coated hydroxyapatite particles. A clinical-histological study in humans].

    PubMed

    Sanz, M; Bascones, A; Kessler, A; García Nuñez, J; Newman, M G; Robertson, M A; Carranza, F A

    1989-05-01

    In this study, histologic behaviour of collagen coated hydroxylapatite particles implanted in human periodontal osseous defects has been analyzed. This material was surgically implanted in four patients, and reentry and block biopsies were carried out 4 and 6 months later. The histologic results demonstrate that this material is well tolerated by surrounding tissues, not eliciting an inflammatory reaction. At four months, the hydroxylapatite particles appear encapsulated by a very cellular connective tissue and at 6 months are found in direct contact with osteoid and mature bone. This material acts as a filler material, being fully biocompatible and stimulating an osseoconductive reaction of the adjacent alveolar bone.

  13. Implantation of placenta-derived mesenchymal stem cells accelerates murine dermal wound closure through immunomodulation

    PubMed Central

    Wang, Haifeng; Chen, Lianyu; Liu, Yang; Luo, Bangzhen; Xie, Nanzi; Tan, Tao; Song, Lige; Erli, Pei; Luo, Ming

    2016-01-01

    Background: Diabetic foot ulcer (DFU) is a major complication of diabetes mellitus. Although previous studies have established that inflammation, ischemia and neuropathy contribute to the development of DFU, it is still an unmet medical need due to lack knowledge of cellular and molecular mechanisms associated with DFU. In the present study, we tested our hypothesis that subcutaneous application of human placental mesenchymal stem cells (PMSCs) can accelerate diabetic dermal wound healing by modulating immunoresponse. Methods and Results: By using an in vivo excisional wound healing model in Goto-Kakizaki (GK) rats, we found that injection of PMSCs accelerates wound closure. Further studies revealed that application of PMSCs can regulate inflammation associated with wound healing by controlling secretion of pro- and anti-inflammatory factors, the beneficial effects can be partially blocked by application of antibodies against interleukin-10 (IL-10). Furthermore, in vitro experiments suggested that co-culture of PMSCs with human dermal fibroblasts can significantly inhibit activation of NF-ĸB induced by lipopolysaccharides (LPS), indicating the molecular mechanism of PMSCs mediated immunomodulation. Conclusion: Taken together, our study suggested that the immunomodulation of PMSCs play an important role on diabetic dermal wound healing process, thus PMSCs might represent an attractive choice for treatment of diabetes dermal wound and DFU. PMID:27904691

  14. Cross-linked xenogenic collagen implantation in the sheep model for vaginal surgery.

    PubMed

    Endo, Masayuki; Urbankova, Iva; Vlacil, Jaromir; Sengupta, Siddarth; Deprest, Thomas; Klosterhalfen, Bernd; Feola, Andrew; Deprest, Jan

    The properties of meshes used in reconstructive surgery affect the host response and biomechanical characteristics of the grafted tissue. Whereas durable synthetics induce a chronic inflammation, biological grafts are usually considered as more biocompatible. The location of implantation is another determinant of the host response: the vagina is a different environment with specific function and anatomy. Herein, we evaluated a cross-linked acellular collagen matrix (ACM), pretreated by the anti-calcification procedure ADAPT® in a sheep model for vaginal surgery. Ten sheep were implanted with a cross-linked ACM, and six controls were implanted with a polypropylene (PP; 56 g/m(2)) control. One implant was inserted in the lower rectovaginal septum, and one was used for abdominal wall defect reconstruction. Grafts were removed after 180 days; all graft-related complications were recorded, and explants underwent bi-axial tensiometry and contractility testing. Half of ACM-implanted animals had palpable induration in the vaginal implantation area, two of these also on the abdominal implant. One animal had a vaginal exposure. Vaginal ACMs were 63 % less stiff compared to abdominal ACM explants (p = 0.01) but comparable to vaginal PP explants. Seven anterior vaginal ACM explants showed areas of graft degradation on histology. There was no overall difference in vaginal contractility. Considering histologic degradation in the anterior vaginal implant as representative for the host, posterior ACM explants of animals with degradation had a 60 % reduced contractility as compared to PP (p = 0.048). Three abdominal implants showed histologic degradation; those were more compliant than non-degraded implants. Vaginal implantation with ACM was associated with graft-related complications (GRCs) and biomechanical properties comparable to PP. Partially degraded ACM had a decreased vaginal contractility.

  15. Enriched Astaxanthin Extract from Haematococcus pluvialis Augments Growth Factor Secretions to Increase Cell Proliferation and Induces MMP1 Degradation to Enhance Collagen Production in Human Dermal Fibroblasts.

    PubMed

    Chou, Hsin-Yu; Lee, Chelsea; Pan, Jian-Liang; Wen, Zhi-Hong; Huang, Shu-Hung; Lan, Chi-Wei John; Liu, Wang-Ta; Hour, Tzyh-Chyuan; Hseu, You-Cheng; Hwang, Byeong Hee; Cheng, Kuo-Chen; Wang, Hui-Min David

    2016-06-16

    Among many antioxidants that are used for the repairing of oxidative stress induced skin damages, we identified the enriched astaxanthin extract (EAE) from Haematococcus pluvialis as a viable ingredient. EAE was extracted from the red microalgae through supercritical fluid carbon dioxide extraction. To compare the effectiveness, EAE wastreated on human dermal fibroblasts with other components, phorbol 12-myristate 13-acetate (PMA), and doxycycline. With sirius red staining and quantitative real-time polymerase chain reaction (qRT-PCR), we found that PMA decreased the collagen concentration and production while overall the addition of doxycycline and EAE increased the collagen concentration in a trial experiments. EAE increased collagen contents through inhibited MMP1 and MMP3 mRNA expression and induced TIMP1, the antagonists of MMPs protein, gene expression. As for when tested for various proteins through western blotting, it was seen that the addition of EAE increased the expression of certain proteins that promote cell proliferation. Testing those previous solutions using growth factor assay, it was noticeable that EAE had a positive impact on cell proliferation and vascular endothelial growth factor (VEGF) than doxycycline, indicating that it was a better alternative treatment for collagen production. To sum up, the data confirmed the possible applications as medical cosmetology agentsand food supplements.

  16. Enriched Astaxanthin Extract from Haematococcus pluvialis Augments Growth Factor Secretions to Increase Cell Proliferation and Induces MMP1 Degradation to Enhance Collagen Production in Human Dermal Fibroblasts

    PubMed Central

    Chou, Hsin-Yu; Lee, Chelsea; Pan, Jian-Liang; Wen, Zhi-Hong; Huang, Shu-Hung; Lan, Chi-Wei John; Liu, Wang-Ta; Hour, Tzyh-Chyuan; Hseu, You-Cheng; Hwang, Byeong Hee; Cheng, Kuo-Chen; Wang, Hui-Min David

    2016-01-01

    Among many antioxidants that are used for the repairing of oxidative stress induced skin damages, we identified the enriched astaxanthin extract (EAE) from Haematococcus pluvialis as a viable ingredient. EAE was extracted from the red microalgae through supercritical fluid carbon dioxide extraction. To compare the effectiveness, EAE wastreated on human dermal fibroblasts with other components, phorbol 12-myristate 13-acetate (PMA), and doxycycline. With sirius red staining and quantitative real-time polymerase chain reaction (qRT-PCR), we found that PMA decreased the collagen concentration and production while overall the addition of doxycycline and EAE increased the collagen concentration in a trial experiments. EAE increased collagen contents through inhibited MMP1 and MMP3 mRNA expression and induced TIMP1, the antagonists of MMPs protein, gene expression. As for when tested for various proteins through western blotting, it was seen that the addition of EAE increased the expression of certain proteins that promote cell proliferation. Testing those previous solutions using growth factor assay, it was noticeable that EAE had a positive impact on cell proliferation and vascular endothelial growth factor (VEGF) than doxycycline, indicating that it was a better alternative treatment for collagen production. To sum up, the data confirmed the possible applications as medical cosmetology agentsand food supplements. PMID:27322248

  17. Discoidin domain receptor 2-microRNA 196a-mediated negative feedback against excess type I collagen expression is impaired in scleroderma dermal fibroblasts.

    PubMed

    Makino, Katsunari; Jinnin, Masatoshi; Aoi, Jun; Hirano, Ayaka; Kajihara, Ikko; Makino, Takamitsu; Sakai, Keisuke; Fukushima, Satoshi; Inoue, Yuji; Ihn, Hironobu

    2013-01-01

    Systemic sclerosis (SSc) is characterized by excess collagen deposition in the skin, due to intrinsic transforming growth factor-β (TGF-β) activation. We tried to determine the expression and the role of discoidin domain receptor 2 (DDR2) in SSc. The expression of DDR2 mRNA and protein was significantly decreased in SSc dermal fibroblasts, which was recovered by knocking down TGF-β. The knockdown of DDR2 in normal fibroblasts induced microRNA-196a expression, which led to type I collagen downregulation, indicating that DDR2 itself has a negative effect on microRNA-196a expression and inducible effect on collagen expression. In SSc fibroblasts, however, the DDR2 knockdown did not affect TGF-β signaling and microRNA-196a expression. The microRNA-196a levels were significantly decreased in normal fibroblasts treated with TGF-β and in SSc fibroblasts. Taken together our data indicate that, in SSc fibroblasts, intrinsic TGF-β stimulation induces type I collagen expression, and also downregulates DDR2 expression. This probably acts as a negative feedback mechanism against excess collagen expression, as a decreased DDR2 expression is supposed to stimulate the microRNA-196a expression and further change the collagen expression. However, in SSc fibroblasts the microRNA-196a expression was downregulated by TGF-β signaling. DDR2-microRNA-196a pathway may be a previously unreported negative feedback system, and its impairment may be involved in the pathogenesis of SSc.

  18. Circular RNA profiling reveals that circCOL3A1-859267 regulate type I collagen expression in photoaged human dermal fibroblasts.

    PubMed

    Peng, Yating; Song, Xiaojing; Zheng, Yue; Wang, Xinyi; Lai, Wei

    2017-04-29

    Production of type I collagen declines is a main characteristic during photoaging, but the mechanism is still not fully understood. Circular RNAs (circRNAs) are a class of newly identified non-coding RNAs with regulatory potency by sequestering miRNAs like a sponge. It's more stable than linear RNAs, and would be a useful tool for regulation of gene expression. However, the role of circRNAs in collagen expression during photoaging is still unclear. Here we performed deep sequencing of RNA generated from UVA irradiated and no irradiated human dermal fibroblasts (HDFs) and identified 29 significantly differentially expressed circRNAs (fold change ≥ 1.5, P < 0.05), 12 circRNAs were up-regulated and 17 circRNAs were down-regulated.3 most differentially expressed circRNAs were verified by qRT-PCR and the down-regulated circCOL3A1-859267 exhibited the most significantly altered in photoaged HDFs. Overexpression of circCOL3A1-859267 inhibited UVA-induced decrease of type I collagen expression and silencing of it reduced type I collagen intensity. Via a bioinformatic method, 44 miRNAs were predicted to binding with circCOL3A1-859267, 5 of them have been confirmed or predicted to interact with type I collagen. This study show that circCOL3A1-859267 regulate type I collagen expression in photoaged HDFs, suggesting it may be a novel target for interfering photoaging.

  19. Quantitative characterization of collagen in the fibrotic capsule surrounding implanted polymeric microparticles through second harmonic generation imaging

    SciTech Connect

    Akilbekova, Dana; Bratlie, Kaitlin M.; Abraham, Thomas

    2015-06-30

    The collagenous capsule formed around an implant will ultimately determine the nature of its in vivo fate. To provide a better understanding of how surface modifications can alter the collagen orientation and composition in the fibrotic capsule, we used second harmonic generation (SHG) microscopy to evaluate collagen organization and structure generated in mice subcutaneously injected with chemically functionalized polystyrene particles. SHG is sensitive to the orientation of a molecule, making it a powerful tool for measuring the alignment of collagen fibers. Additionally, SHG arises from the second order susceptibility of the interrogated molecule in response to the electric field. Variation in these tensor components distinguishes different molecular sources of SHG, providing collagen type specificity. Here, we demonstrated the ability of SHG to differentiate collagen type I and type III quantitatively and used this method to examine fibrous capsules of implanted polystyrene particles. Data presented in this work shows a wide range of collagen fiber orientations and collagen compositions in response to surface functionalized polystyrene particles. Dimethylamino functionalized particles were able to form a thin collagenous matrix resembling healthy skin. These findings have the potential to improve the fundamental understanding of how material properties influence collagen organization and composition quantitatively.

  20. Quantitative characterization of collagen in the fibrotic capsule surrounding implanted polymeric microparticles through second harmonic generation imaging

    DOE PAGES

    Akilbekova, Dana; Bratlie, Kaitlin M.; Abraham, Thomas

    2015-06-30

    The collagenous capsule formed around an implant will ultimately determine the nature of its in vivo fate. To provide a better understanding of how surface modifications can alter the collagen orientation and composition in the fibrotic capsule, we used second harmonic generation (SHG) microscopy to evaluate collagen organization and structure generated in mice subcutaneously injected with chemically functionalized polystyrene particles. SHG is sensitive to the orientation of a molecule, making it a powerful tool for measuring the alignment of collagen fibers. Additionally, SHG arises from the second order susceptibility of the interrogated molecule in response to the electric field. Variationmore » in these tensor components distinguishes different molecular sources of SHG, providing collagen type specificity. Here, we demonstrated the ability of SHG to differentiate collagen type I and type III quantitatively and used this method to examine fibrous capsules of implanted polystyrene particles. Data presented in this work shows a wide range of collagen fiber orientations and collagen compositions in response to surface functionalized polystyrene particles. Dimethylamino functionalized particles were able to form a thin collagenous matrix resembling healthy skin. These findings have the potential to improve the fundamental understanding of how material properties influence collagen organization and composition quantitatively.« less

  1. Tissue integration of the collagen-hydroxylapatite implant: histological examination in canine bone and surrounding tissues.

    PubMed

    Remacle, M; Marbaix, E; Mustin, V

    1991-01-01

    Using the dog as an animal model, we have tested an implant material composed of purified fibrillar collagen (PFC) and particulate hydroxylapatite (HA) in the mandible and in surrounding tissues. Bone and tissue samples were taken at 2, 4 and 6 months for histological study. After 2 months, the PFC was replaced by fibro-connective host tissues. After 4 months, some small areas of ossification were observed around the HA particles. After 6 months, the fibro-connective tissue was replaced by neo-formed bone in the mandible. PFC was found to increase the interfaces between the HA particles and the host tissues, permitting HA integration into the bone. The PFC/HA implant was also molded when moistened by blood or saline solution and then became mis-sharpen by local pressures exerted. These findings show that the implant should preferably be reserved for the restoration of bones not subjected to significant forces or local stresses.

  2. One-stage Reconstruction of Soft Tissue Defects with the Sandwich Technique: Collagen-elastin Dermal Template and Skin Grafts

    PubMed Central

    Wollina, Uwe

    2011-01-01

    Background: A full-thickness soft tissue defect closure often needs complex procedures. The use of dermal templates can be helpful in improving the outcome. Objective: The objective was to evaluate a sandwich technique combining the dermal collagen–elastin matrix with skin grafts in a one-stage procedure. Materials and Methods: Twenty-three patients with 27 wounds were enrolled in this prospective single-centre observational study. The mean age was 74.8 ± 17.2 years. Included were full-thickness defects with exposed bone, cartilage and/ or tendons. The dermal collagen–elastin matrix was applied onto the wound bed accomplished by skin transplants, i.e. ‘sandwich’ transplantation. In six wounds, the transplants were treated with intermittent negative pressure therapy. Results: The size of defects was ≤875 cm2. The use of the dermal template resulted in a complete and stable granulation in 100% of wounds. Seventeen defects showed a complete closure and 19 achieved a complete granulation with an incomplete closure. There was a marked pain relief. No adverse events were noted due to the dermal template usage. Conclusions: Sandwich transplantation with the collagen–elastin matrix is a useful tool when dealing with full-thickness soft tissue defects with exposed bone, cartilage or tendons. PMID:22279382

  3. Actions of melatonin mixed with collagenized porcine bone versus porcine bone only on osteointegration of dental implants.

    PubMed

    Calvo-Guirado, José Luis; Gómez-Moreno, Gerardo; López-Marí, Laura; Guardia, Javier; Marínez-González, José María; Barone, Antonio; Tresguerres, Isabel F; Paredes, Sergio D; Fuentes-Breto, Lorena

    2010-04-01

    This study evaluated the effect of the topical application of melatonin mixed with collagenized porcine bone on the osteointegration on the rough discrete calcium deposit (DCD) surface implants in Beagle dogs 3 months after their insertion. In preparation for subsequent insertion of dental implants, lower molars were extracted from 12 Beagle dogs. Each mandible received two parallel wall expanded platform implants with a DCD surface of 4 mm in diameter and 10 mm in length. The implants were randomly assigned to the distal sites on each mandible in the molar area and the gaps were filled with 5 mg lyophilized powdered melatonin and porcine bone and collagenized porcine bone alone. Ten histological sections per implant were obtained for histomorphometric studies. After a 4-wk treatment period, melatonin plus porcine bone significantly increased the perimeter of bone that was in direct contact with the treated implants (P < 0.0001), bone density (P < 0.0001), and new bone formation (P < 0.0001) in comparison with porcine bone alone around the implants. Melatonin plus collagenized porcine bone on DCD surface may act as a biomimetic agent in the placement of endo-osseous dental implants and enhance the osteointegration. Melatonin combined with porcine bone on DCD implants reveals more bone in implant contact at 12 wk (84.5 +/- 1.5%) compared with porcine bone alone treated area (67.17 +/- 1.2%).

  4. Effect of defective collagen synthesis on epithelial implant interface: lathyritic model in dogs. An experimental preliminary study.

    PubMed

    Cengiz, Murat Inanç; Kirtiloğlu, Tuğrul; Acikgoz, Gökhan; Trisi, Paolo; Wang, Hom-Lay

    2012-04-01

    Peri-implant mucosa is composed of 2 compartments: a marginal junctional epithelium and a zone of connective tissue attachment. Both structures consist mainly of collagen. Lathyrism is characterized by defective collagen synthesis due to inhibition of lysyl oxidase, an enzyme that is essential for interfibrillar collagen cross-linking. The lathyritic agent beta-aminoproprionitrile (β-APN) is considered a suitable agent to disrupt the connective tissue metabolism. Therefore, the purpose of this study was to assess the effect of defective connective tissue metabolism on epithelial implant interface by using β-APN created chronic lathyrism in the canine model. Two 1-year-old male dogs were included in this study. A β-APN dosage of 5 mg/0.4 mL/volume 100 g/body weight was given to the test dog for 10 months, until lathyritic symptoms developed. After this, the mandibular premolar teeth (p2, p3, p4) of both dogs were atraumatically extracted, and the investigators waited 3 months before implants were placed. In the test dog, 3 implants were placed in the left mandible, and 2 implants were placed in the right mandible. In the control dog, 2 implants were placed in the left mandibular premolar site. The dogs were sacrificed 10 months after healing. Peri-implant tissues obtained from the dogs were examined histomorphologically and histopathologically. Bone to implant contact (BIC) values and bone volumes (BV) were lower in the lathyritic group compared to the control group; however, no statistical significance was found. Significant histologic and histomorphometric changes were observed in peri-implant bone, connective tissue, and peri-implant mucosal width between test and control implants. Defective collagen metabolism such as lathyrism may negatively influence the interface between implant and surrounding soft tissue attachment.

  5. Increase in dermal collagen fibril diameter and elastogenesis with UVB exposure: an optical and ultrastructural study in albino Balb/c mice.

    PubMed

    Carneiro, Sueli Coelho; Cassia, Flavia de Freire; Pascarelli, Bernardo Miguel; Souza, Sonia Oliveira; Ramos-e-Silva, Marcia; Filgueira, Absalom Lima; Japiassu, Maria Augusta; Takiya, Christina Maeda

    2007-01-01

    Cutaneous aging is a complex biological phenomenon, dependent not only on the innate or intrinsic process ("biological clock"), but also on extrinsic elements, primarily chronic sun exposure (photoaging). In order to verify dermal morphological changes in the elastic fiber system and collagen associated with aged skin, we performed a light and electron microscopic study on exposed-shaved albino mice, which were exposed to UVB radiation. The experimental group consisted of 48 exposed animals, randomly distributed in three groups and submitted to different radiation doses (A, 28800 J/m2; B, 57600 J/m2; and C, 86400 J/m2) and studied 0, 30, 60 and 90 days of exposure discontinuation. Nonexposed-shaved and nonexposed-nonshaved animals were included as controls. From the day of exposure discontinuation and subsequently, the elastic system and collagen network were progressively modified. The increase in collagen fibril diameter was prominent in the 60 and 90 day groups (p<0.05), as noticed on electron microscopy. Elastic fiber density also increased after irradiation (p<0.05). On electron microscopy, elastogenesis was seen in the deep dermis. The comparative study among the groups disclosed clear relationship between doses and "elastotic changes". It also showed that chronological aging of mice skin was apparently intensified after UVB exposure. Skin elastogenesis seems to be a major consequence of UVB exposure, apart from elastolysis, and occurs not only in humans but also in hairless mice submitted to continuous, long-term UVB exposure.

  6. Implants of polyanionic collagen matrix in bone defects of ovariectomized rats.

    PubMed

    Cunha, Marcelo Rodrigues; Santos, Arnaldo Rodrigues; Goissis, Gilberto; Genari, Selma C

    2008-03-01

    In recent years, there has been a great interest in the development of biomaterials that could be used in the repair of bone defects. Collagen matrix (CM) has the advantage that it can be modified chemically to improve its mechanical properties. The aim of the present study was to evaluate the effect of three-dimensional membranes of native or anionic (submitted to alkaline treatment for 48 or 96 h) collagen matrix on the consolidation of osteoporosis bone fractures resulting from the gonadal hormone alterations caused by ovariectomy in rats subjected to hormone replacement therapy. The animals received the implants 4 months after ovariectomy and were sacrificed 8 weeks after implantation of the membranes into 4-mm wide bone defects created in the distal third of the femur with a surgical bur. Macroscopic analysis revealed the absence of pathological alterations in the implanted areas, suggesting that the material was biocompatible. Microscopic analysis showed a lower amount of bone ingrowth in the areas receiving the native membrane compared to the bone defects filled with the anionic membranes. In ovariectomized animals receiving anionic membranes, a delay in bone regeneration was observed mainly in animals not subjected to hormone replacement therapy. We conclude that anionic membranes treated with alkaline solution for 48 and 96 h presented better results in terms of bone ingrowth.

  7. [Facial foreign body granulomas after dermal injection of a polylactate-based implant for wrinkles].

    PubMed

    Oppel, Tilmann; Schaller, Martin; Flaig, Michael; Korting, Hans Christina

    2003-03-01

    New methods are constantly introduced for soft tissue augmentation to correction of scars and wrinkles. Each method has its advantages and disadvantages. A 48 year old woman developed visible and palpable plaques and papules after treatment of the nasolabial and glabella folds with a poly L-lactic acid implant. Histological examination revealed a foreign body granuloma, while electron microscopy showed remnants of the implant material, demonstrating that poly L-lactic acid can also induce a foreign body reaction.

  8. Adaptation of the dermal collagen structure of human skin and scar tissue in response to stretch: an experimental study.

    PubMed

    Verhaegen, Pauline D; Schouten, Hennie J; Tigchelaar-Gutter, Wikky; van Marle, Jan; van Noorden, Cornelis J; Middelkoop, Esther; van Zuijlen, Paul P

    2012-01-01

    Surgeons are often faced with large defects that are difficult to close. Stretching adjacent skin can facilitate wound closure. In clinical practice, intraoperative stretching is performed in a cyclical or continuous fashion. However, exact mechanisms of tissue adaptation to stretch remain unclear. Therefore, we investigated collagen and elastin orientation and morphology of stretched and nonstretched healthy skin and scars. Tissue samples were stretched, fixed in stretched-out position, and processed for histology. Objective methods were used to quantify the collagen orientation index (COI), bundle thickness, and bundle spacing. Also sections were analyzed for elastin orientation and quantity. Significantly more parallel aligned collagen bundles were found after cyclical (COI = 0.57) and continuous stretch (COI = 0.57) compared with nonstretched skin (COI = 0.40). Similarly, more parallel aligned elastin was found after stretch. Also, significantly thicker collagen bundles and more bundle spacing were found after stretch. For stretched scars, significantly more parallel aligned collagen was found (COI = 0.61) compared with nonstretched scars (COI = 0.49). In conclusion, both elastin and collagen realign in a parallel fashion in response to stretch. For healthy skin, thicker bundles and more space between the bundles were found. Rapid changes in extension, alignment, and collagen morphology appear to be the underlying mechanisms of adaptation to stretching.

  9. Noninvasive and High-Resolution Optical Monitoring of Healing of Diabetic Dermal Excisional Wounds Implanted with Biodegradable In Situ Gelable Hydrogels

    PubMed Central

    Yuan, Zhijia; Zakhaleva, Julia; Ren, Hugang; Liu, Jingxuan; Chen, Weiliam

    2010-01-01

    Closure of diabetic dermal chronic wounds remains a clinical challenge. Implant-assisted healing is emerging as a potential class of therapy for dermal wound closure; this advancement has not been paralleled by the development in complementary diagnostic techniques to objectively monitor the wound-healing process in conjunction with assessing/monitoring of implant efficacy. Biopsies provide the most objective morphological assessments of wound healing; however, they not only perpetuate the wound presence but also increase the risk of infection. A noninvasive and high-resolution imaging technique is highly desirable to provide objective longitudinal diagnosis of implant-assisted wound healing. We investigated the feasibility of deploying optical coherence tomography (OCT) for noninvasive monitoring of the healing of full-thickness excisional dermal wounds implanted with a novel in situ gelable hydrogel composed of N-carboxyethyl chitosan, oxidized dextran, and hyaluronan, in both normal and db/db mice. The results showed that OCT was able to differentiate the morphological differences (e.g., thickness of dermis) between normal and diabetic mice as validated by their corresponding histological evaluations (p < 0.05). OCT could detect essential morphological changes during wound healing, including re-epithelization, inflammatory response, and granulation tissue formation as well as impaired wound repair in diabetic mice. Importantly, by tracking specific morphological changes in hydrogel-assisted wound healing (e.g., implants' degradation and resorption, cell-mediated hydrogel degradation, and accelerated re-epithelization), OCT could also be deployed to monitor and evaluate the transformation of implanted biomaterials, thus holding the promise for noninvasive and objective monitoring of wound healing longitudinally and for objective efficacy assessment of implantable therapeutics in tissue engineering. PMID:19496703

  10. Th17 cells favor inflammatory responses while inhibiting type I collagen deposition by dermal fibroblasts: differential effects in healthy and systemic sclerosis fibroblasts

    PubMed Central

    2013-01-01

    Introduction T helper (Th)-17 cells are increased in systemic sclerosis (SSc). We therefore assessed whether Th17 cells could modulate the inflammatory and fibrotic responses in dermal fibroblasts from healthy donors (HD) and SSc individuals. Methods Fibroblasts were obtained from 14 SSc and 8 HD skin biopsies. Th17 clones were generated from healthy peripheral blood upon enrichment of CC chemokine receptor (CCR)-4/CCR6/CD161 expressing cells. Their cytokine production was assessed by flow cytometry and multiplex beads immunoassay. Fibroblast production of monocyte chemoattractant protein (MCP)-1, interleukin (IL)-8, matrix metalloproteinase (MMP)-1, tissue inhibitor of metalloproteinase (TIMP)-1, MMP-2 and type-I collagen was quantified by enzyme-linked immunosorbent assay (ELISA) and radioimmunoassay (RIA), and changes in their transcription levels assessed by real-time PCR. Intracellular signals were dissected by western blot and the use of pharmacological inhibitors. IL-17A, tumor necrosis factor (TNF) and interferon-gamma (IFN-γ) blocking reagents were used to assess the specificity of the observed effects. Results IL-17A increased MCP-1, IL-8 and MMP-1 production in a dose-dependent manner while having no effect on type I collagen in HD and SSc fibroblasts both at protein and mRNA levels. Nuclear factor-kappa B (NF-κB) and p38 were preferentially involved in the induction of MCP-1 and IL-8, while MMP-1 was most dependent on c-Jun N-terminal kinase (JNK). Supernatants of activated Th17 clones largely enhanced MCP-1, IL-8 and MMP-1 while strongly inhibiting collagen production. Of note, the production of MCP-1 and IL-8 was higher, while collagen inhibition was lower in SSc compared to HD fibroblasts. The Th17 clone supernatant effects were mostly dependent on additive/synergistic activities between IL-17A, TNF and in part IFN-γ. Importantly, the inhibition of type I collagen production induced by the Th17 clone supernatants was completely abrogated by

  11. Role of xenogenous bovine platelet gel embedded within collagen implant on tendon healing: an in vitro and in vivo study

    PubMed Central

    Oryan, Ahmad; Meimandi-Parizi, Abdolhamid; Maffulli, Nicola

    2015-01-01

    Surgical reconstruction of large Achilles tendon defects is demanding. Platelet concentrates may be useful to favor healing in such conditions. The characteristics of bovine platelet-gel embedded within a collagen-implant were determined in vitro, and its healing efficacy was examined in a large Achilles tendon defect in rabbits. Two cm of the left Achilles tendon of 60 rabbits were excised, and the animals were randomly assigned to control (no implant), collagen-implant, or bovine-platelet-gel-collagen-implant groups. The tendon edges were maintained aligned using a Kessler suture. No implant was inserted in the control group. In the two other groups, a collagen-implant or bovine-platelet-gel-collagen-implant was inserted in the defect. The bioelectricity and serum platelet-derived growth factor levels were measured weekly and at 60 days post injury, respectively. After euthanasia at 60 days post injury, the tendons were tested at macroscopic, microscopic, and ultrastructural levels, and their dry matter and biomechanical performances were also assessed. Another 60 rabbits were assigned to receive no implant, a collagen-implant, or a bovine-platelet-gel-collagen-implant, euthanized at 10, 20, 30, and 40 days post injury, and their tendons were evaluated grossly and histologically to determine host-graft interactions. Compared to the control and collagen-implant, treatment with bovine-platelet-gel-collagen-implant improved tissue bioelectricity and serum platelet-derived growth factor levels, and increased cell proliferation, differentiation, and maturation. It also increased number, diameter, and density of the collagen fibrils, alignment and maturation of the collagen fibrils and fibers, biomechanical properties and dry matter content of the injured tendons at 60 days post injury. The bovine-platelet-gel-collagen-implant also increased biodegradability, biocompatibility, and tissue incorporation behavior of the implant compared to the collagen-implant alone

  12. Clinical and radiographic evaluation of copolymerized Polylactic/polyglycolic acids as a bone filler in combination with a cellular dermal matrix graft around immediate implants

    PubMed Central

    Soliman, Mahitab M.; Zaki, Azza Abdulrahman; El Gazaerly, Hanaa Mohamed; Shemmrani, Ammar Al; Sorour, Abd El Latif

    2014-01-01

    Objective This study was conducted to evaluate clinically and radiographically the use of a cellular dermal matrix allograft (Alloderm) in combination with PLA/PGA (Fisiograft) around immediate implants. Materials and Methods Fourteen patients were included in this study, three patients received two implants, total of seventeen implants were placed. Periapical radiographs and orthopantomographs were taken. The selected teeth were extracted atraumatically after the reflection of full thickness flaps. One-piece Zimmer implants were placed immediately into the sockets. Weeks from implantation, radiographic evaluation was made at 6 Fisiograft in powder form was placed in the osseous defects around the implants. The implants were immediately restored with provisional crowns free from occlusion. Patients were clinically evaluated at 3, 6, and 14 months after loading which was done after 6 weeks from implantation. Radiographic evaluation was made at 6 and 14 months from implant placement. Results showed that immediate implantation was successful in sixteen out of seventeen implants, clinical parameters regarding plaque index, gingival index, there was a slight decrease through the follow-up periods from 3 to 14 months but it was non-significant, while there was a significant decrease in the probing depth. Radiographically there was a significant increase in the bone density from 6 to 14 months post loading, while the vertical bone defect was significantly decreased. The fisiograft functioned well as space maker and scaffolding material. The Alloderm performed well as a membrane to be used in association with immediate implants and it has a good potentiality for increasing the width of the keratinized gingiva, which is an important feature for implant esthetics. Conclusion the combination technique between the bone graft and the membrane proved to be successful to overcome dehiscence and osseous defects around immediate implants. PMID:25780357

  13. In situ visualization of dermal collagen dynamics during skin burn healing using second-harmonic-generation microscopy

    NASA Astrophysics Data System (ADS)

    Yasui, Takeshi; Hase, Eiji; Tanaka, Ryosuke; Fukushima, Shu-ichiro; Araki, Tsutomu

    2015-06-01

    Burn healing is a process to repair thermally damaged tissues. Although burn healing has many aspects, it is common for dynamics of collagen fiber, such as decomposition, production, or growth, to be closely related with burn healing. If such healing process can be visualized from the viewpoint of the collagen dynamics, one may obtain new findings regarding biological repairing mechanisms in the healing process. To this end, second-harmonic-generation (SHG) light will be an effective optical probe because of high selectivity and good image contrast to collagen molecules as well as high spatial resolution, optical three-dimensional (3D) sectioning, minimal invasiveness, deep penetration, the absence of interference from background light, and in situ measurement without additional staining. Furthermore, since SHG light arises from a non-centrosymmetric triple helix of three polypeptide chains in the collagen molecule, its intensity decreases and finally disappears when thermal denaturation caused by the skin burn changes the structure of this molecule to a centrosymmetric random coil. Therefore, optical assessment of skin burn has been investigated by SHG microscopy. In this paper, we applied SHG microscopy for in situ imaging of the healing process in animal skin burn and successfully visualized the decomposition, production, and growth of renewal collagen fibers as a series of time-lapse images in the same subject.

  14. Composite poly-L-lactic acid/poly-(α,β)-DL-aspartic acid/collagen nanofibrous scaffolds for dermal tissue regeneration.

    PubMed

    Ravichandran, Rajeswari; Venugopal, Jayarama Reddy; Sundarrajan, Subramanian; Mukherjee, Shayanti; Sridhar, Radhakrishnan; Ramakrishna, Seeram

    2012-08-01

    Tissue engineering scaffolds for skin tissue regeneration is an ever expounding area of research, as the products that meet the necessary requirements are far and elite. The nanofibrous poly-L-lactic acid/poly-(α,β)-DL-aspartic acid/Collagen (PLLA/PAA/Col I&III) scaffolds were fabricated by electrospinning and characterized by SEM, contact angle and FTIR analysis for skin tissue regeneration. The cell-scaffold interactions were analyzed by cell proliferation and their morphology observed in SEM. The results showed that the cell proliferation was significantly increased (p≤0.05) in PLLA/PAA/Col I&III scaffolds compared to PLLA and PLLA/PAA nanofibrous scaffolds. The abundance and accessibility of adipose derived stem cells (ADSCs) may prove to be novel cell therapeutics for dermal tissue regeneration. The differentiation of ADSCs was confirmed using collagen expression and their morphology by CMFDA dye extrusion technique. The current study focuses on the application of PLLA/PAA/Col I&III nanofibrous scaffolds for skin tissue engineering and their potential use as substrate for the culture and differentiation of ADSCs. The objective for inclusion of a novel cell binding moiety like PAA was to replace damaged extracellular matrix and to guide new cells directly into the wound bed with enhanced proliferation and overall organization. This combinatorial epitome of PLLA/PAA/Col I&III nanofibrous scaffold with stem cell therapy to induce the necessary paracrine signalling effect would favour faster regeneration of the damaged skin tissues.

  15. Post implantation fate of adipogenic induced mesenchymal stem cells on Type I collagen scaffold in a rat model.

    PubMed

    Venugopal, Balu; Fernandez, Francis B; Harikrishnan, V S; John, Annie

    2017-02-01

    Regenerative medicine via its application in soft tissue reconstruction through novel methods in adipose tissue engineering (ATE) has gained remarkable attention and investment despite simultaneous reports on clinical incidence of graft resorption and impaired vascularization. The underlying malaise here once identified may play a critical role in optimizing implant function. Our work attempts to determine the fate of donor cells and the implant in recipient micro environment using adipose-derived mesenchymal stem cells (ASCs) on a type I collagen sponge, an established scaffold for ATE. Cell components within the construct were identified 21 days post implantation to delineate cell survival, proliferation & terminal roles in vivo. ASC's are multipotent, while collagen type I is a natural extra cellular matrix component. Commercially available bovine type I collagen was characterized for its physiochemical properties and cyto-compatibility. Nile red staining of induced ASCs identified red globular structures in cell cytoplasm indicating oil droplet accumulation. Similarly, in vivo implantation of the cell seeded collagen construct in rat model for 21 days in the dorsal muscle, showed genesis of chicken wire network of fat-like cells, which was demonstrated histologically using a variety of staining techniques. Furthermore, fluorescent in situ hybridization (FISH) technique established the efficiency of transplantation wherein the male donor cells with labeled Y chromosome was identified 21 days post implantation from female rat model. Retrieved samples at 21 days indicated adipogenesis in situ, with donor cells highlighted via FISH. The study provides an insight to stem cells in ATE from genesis to functionalization.

  16. Autologous implantation of BMP2-expressing dermal fibroblasts to improve bone mineral density and architecture in rabbit long bones.

    PubMed

    Ishihara, Akikazu; Weisbrode, Steve E; Bertone, Alicia L

    2015-10-01

    Cell-mediated gene therapy may treat bone fragility disorders. Dermal fibroblasts (DFb) may be an alternative cell source to stem cells for orthopedic gene therapy because of their rapid cell yield and excellent plasticity with bone morphogenetic protein-2 (BMP2) gene transduction. Autologous DFb or BMP2-expressing autologous DFb were administered in twelve rabbits by two delivery routes; a transcortical intra-medullar infusion into tibiae and delayed intra-osseous injection into femoral drill defects. Both delivery methods of DFb-BMP2 resulted in a successful cell engraftment, increased bone volume, bone mineral density, improved trabecular bone microarchitecture, greater bone defect filling, external callus formation, and trabecular surface area, compared to non-transduced DFb or no cells. Cell engraftment within trabecular bone and bone marrow tissue was most efficiently achieved by intra-osseous injection of DFb-BMP2. Our results suggested that BMP2-expressing autologous DFb have enhanced efficiency of engraftment in target bones resulting in a measurable biologic response by the bone of improved bone mineral density and bone microarchitecture. These results support that autologous implantation of DFb-BMP2 warrants further study on animal models of bone fragility disorders, such as osteogenesis imperfecta and osteoporosis to potentially enhance bone quality, particularly along with other gene modification of these diseases.

  17. Treatment of an early failing implant by guided bone regeneration using resorbable collagen membrane and bioactive glass

    PubMed Central

    Talreja, Prakash S.; Gayathri, G. V.; Mehta, D. S.

    2013-01-01

    Implant failure can be divided into early (prior to prosthetic treatment) or late (after prosthetic rehabilitation). Early failure is generally due to interference in the healing process after implant placement. Implants undergoing early failure will show progressive bone loss on radiographs during the healing period (4 to 6 weeks). In the present case report, early progressive bone loss was seen at 6 weeks, after placement of a non-submerged single piece mini implant. Clinical examination revealed peri-implant bleeding on probing and pocket and grade-1 mobility. Treatment protocol included mechanical debridement (plastic curettes), chemical detoxification with supersaturated solution of citric acid, antibiotics and guided bone regeneration therapy using the collagen membrane as guided bone regeneration barrier in combination with bioactive glass as bone grafting material. The 6 month postoperative examination showed complete resolution of the osseous defect, thus suggesting that this technique may hold promise in the treatment of implants undergoing early failure. PMID:23633789

  18. Collagen scaffold meniscus implant integration in a canine model: a histological analysis.

    PubMed

    Hansen, Robert; Bryk, Eli; Vigorita, Vincent

    2013-12-01

    In the situation of an irreparable meniscus tear, an implant comparable to a normal meniscus is an attractive option. Using a canine model, we assessed the early and late histologic response to a tissue engineered meniscal collagen scaffold (CS). All animals received bilateral arthrotomies, and all joints receiving the CS had an 80% resection of the meniscus. Animals were sacrificed at 3 and 6 weeks, and 12, 13, and 17 months. The CS/tissue complex and host meniscal rim were sectioned for histologic examination with specific focus on the extracellular matrix, angiogenesis, cellular resorption of the scaffold, scaffold appearance, and CS/Host integration. Early histologic samples (3-6 weeks) revealed active angiogenesis and fibrin clots evolving into cellular granulation type tissue. At 12 months, a mature fibrochondrocytic matrix was depositing with gradations of dissolution and integration of the CS implant. Maturing CS/host integration was observed at 18 months. Active cellular resorption of the implant decreased over time. Four cases showed a mild non-specific chronic inflammation and one additional case showed inflammatory engulfment of the scaffold with giant cells at 3 weeks. No evidence of infection either clinically or histologically was observed at any time point. Overall, this histologic analysis demonstrated the active integration of a meniscal like cartilage into a tissue engineered biological scaffold in a canine model.

  19. Changes of the peri-implant soft tissue thickness after grafting with a collagen matrix

    PubMed Central

    Zafiropoulos, Gregory-George; Deli, Giorgio; Hoffmann, Oliver; John, Gordon

    2016-01-01

    Background: The aim of this study was to determine the treatment outcome of the use of a porcine monolayer collagen matrix (mCM) to increase soft-tissue volume as a part of implant site development. Materials and Methods: Implants were placed in single sites in 27 patients. In the test group, mCM was used for soft-tissue augmentation. No graft was placed in the control group. Soft-tissue thickness (STTh) was measured at the time of surgery (T0) and 6 months postoperatively (T1) at two sites (STTh 1, 1 mm below the gingival margin; STTh 2, 3 mm below the mucogingival margin). Results: Significant increases (P < 0.001) in STTh (STTh 1 = 1.06 mm, 117%; STTh 2 = 0.89 mm, 81%) were observed in the test group. Biopsy results showed angiogenesis and mature connective tissue covered by keratinized epithelium. Conclusions: Within the limitations of this study, it could be concluded that mCM leads to a significant increase of peri-implant soft-tissue thickness, with good histological integration and replacement by soft tissue and may serve as an alternative to connective tissue grafting. PMID:28298828

  20. Alveolar ridge preservation with deproteinized bovine bone graft and collagen membrane and delayed implants.

    PubMed

    Pang, Chaoyuan; Ding, Yuxiang; Zhou, Hongzhi; Qin, Ruifeng; Hou, Rui; Zhang, Guoliang; Hu, Kaijin

    2014-09-01

    To evaluate clinically and radiographically an alveolar ridge, preservation technique with deproteinized bovine bone graft and absorbable collagen membrane and then restoration with delayed implants were done. The study included 30 patients. The trial group's sockets were filled with deproteinized bovine bone graft (Bio-Oss) and covered with absorbable collagen membrane (Bio-Gide). The control group's sockets healed without any treatment. Panoramic radiograph and computed tomography were taken immediately after graft and 3 and 6 months later to evaluate the height, width, and volume change of the alveolar ridge bone. Dental implants were inserted in all sockets at 6 months, and osseointegration condition was evaluated in the following 12 months. All sockets healed uneventfully. In the trial group, the mean (SD) height reduction of the alveolar ridge bone was 1.05 (0.24) mm at 3 months and 1.54 (0.25) mm at 6 months. The width reduction was 1.11 (0.13) mm at 3 months and 1.84 (0.35) mm at 6 months. Bone volume reduction was 193.79 (21.47) mm at 3 months and 262.06 (33.08) mm at 6 months. At the same trend, in the control group, the bone height reduction was 2.12 (0.15) mm at 3 months and 3.26 (0.29) mm at 6 months. The width reduction was 2.72 (0.19) mm at 3 months and 3.56 (0.28) mm at 6 months. Bone volume reduction was 252.19 (37.21) mm at 3 months and 342.32 (36.41) mm at 6 months. There was a significant difference in alveolar ridge bone height, width, and volume reduction in the 2 groups. The osseointegration condition had no significant difference between the 2 groups. This study suggested that the deproteinized bovine bone graft and absorbable collagen membrane were beneficial to preserve the alveolar ridge bone and had no influence on the osseointegration of delayed implant.

  1. Clinical safety and efficacy of implantation of octacalcium phosphate collagen composites in tooth extraction sockets and cyst holes.

    PubMed

    Kawai, Tadashi; Tanuma, Yuji; Matsui, Keiko; Suzuki, Osamu; Takahashi, Tetsu; Kamakura, Shinji

    2016-01-01

    It was demonstrated that octacalcium phosphate collagen composite achieved notable bone regeneration in bone defects in preclinical studies. On the basis of the research results, an investigator-initiated exploratory clinical trial was conducted after approval from a local Institutional Review Board. This clinical study was performed as a single-arm non-randomized intervention study. Octacalcium phosphate collagen composite was implanted into a total of 10 cases of alveolar bone defects after tooth extractions and cystectomy. Safety assessment was performed in terms of the clinical course and several consecutive laboratory examinations, and sequential radiographs were used for efficacy assessment. All participants uneventfully completed the clinical trial without major problems in their general condition. Postoperative wound swelling was observed, as also commonly seen in tooth extraction or cystectomy. Although no serious liver dysfunction, renal dysfunction, electrolyte imbalance, or abnormal urinalysis results were recognized, the number of white blood cells and C-reactive protein level temporarily increased after the operation. An increase in radiopacity in the octacalcium phosphate collagen composite-implanted site was observed in all cases. Finally, the border between the original bone and the octacalcium phosphate collagen composite-implanted site became indistinguishable. These results suggest that octacalcium phosphate collagen composite could be utilized safely in clinical situations in the future.

  2. Clinical safety and efficacy of implantation of octacalcium phosphate collagen composites in tooth extraction sockets and cyst holes

    PubMed Central

    Kawai, Tadashi; Tanuma, Yuji; Matsui, Keiko; Suzuki, Osamu; Takahashi, Tetsu; Kamakura, Shinji

    2016-01-01

    It was demonstrated that octacalcium phosphate collagen composite achieved notable bone regeneration in bone defects in preclinical studies. On the basis of the research results, an investigator-initiated exploratory clinical trial was conducted after approval from a local Institutional Review Board. This clinical study was performed as a single-arm non-randomized intervention study. Octacalcium phosphate collagen composite was implanted into a total of 10 cases of alveolar bone defects after tooth extractions and cystectomy. Safety assessment was performed in terms of the clinical course and several consecutive laboratory examinations, and sequential radiographs were used for efficacy assessment. All participants uneventfully completed the clinical trial without major problems in their general condition. Postoperative wound swelling was observed, as also commonly seen in tooth extraction or cystectomy. Although no serious liver dysfunction, renal dysfunction, electrolyte imbalance, or abnormal urinalysis results were recognized, the number of white blood cells and C-reactive protein level temporarily increased after the operation. An increase in radiopacity in the octacalcium phosphate collagen composite–implanted site was observed in all cases. Finally, the border between the original bone and the octacalcium phosphate collagen composite–implanted site became indistinguishable. These results suggest that octacalcium phosphate collagen composite could be utilized safely in clinical situations in the future. PMID:27757220

  3. Evaluation of dermal-epidermal skin equivalents ('composite-skin') of human keratinocytes in a collagen-glycosaminoglycan matrix(Integra artificial skin).

    PubMed

    Kremer, M; Lang, E; Berger, A C

    2000-09-01

    Integra artificial skin (Integra LifeSciences Corp., Plainsboro, NJ, USA) is a dermal template consisting of bovine collagen, chondroitin-6-sulphate and a silastic membrane manufactured as Integra. This product has gained widespread use in the clinical treatment of third degree burn wounds and full thickness skin defects of different aetiologies. The product was designed to significantly reduce the time needed to achieve final wound closure in the treatment of major burn wounds, to optimise the sparse autologous donor skin resources and to improve the durable mechanical quality of the skin substitute. The clinical procedure requires two stages. The first step creates a self neodermis, the second creates a self epidermis on the neodermis. However, it is desirable to cover major burn wounds early in a single step by a skin substitute consisting of a dermal equivalent seeded in vitro with autologous keratinocytes ('composite-skin') out of which a full thickness skin develops in vivo.The goal of this experimental study was to develop a method to integrate human keratinocytes in homogeneous distribution and depth into Integra Artificial Skin. The seeded cell-matrix composites were grafted onto athymic mice in order to evaluate their potential to reconstitute a human epidermis in vivo. We were able to demonstrate that the inoculated human keratinocytes reproducibly displayed a homogeneous pattern of distribution, adherence, proliferation and confluence. The cell-matrix composites grafted in this model exhibited good wound adherence, complete healing, minor wound contraction and had the potential to reconstitute an elastic, functional and durable human skin. Histologically we were able to show that the inoculated human keratinocytes in vivo colonised the matrix in a histomorphologically characteristic epidermal pattern (keratomorula, keratinocyte bubbling) and developed a persisting, stratified, keratinising epidermis which immunohistologically proved to be of human

  4. Fibrin and collagen differentially but synergistically regulate sprout angiogenesis of human dermal microvascular endothelial cells in 3-dimensional matrix.

    PubMed

    Feng, Xiaodong; Tonnesen, Marcia G; Mousa, Shaker A; Clark, Richard A F

    2013-01-01

    Angiogenesis is a highly regulated event involving complex, dynamic interactions between microvascular endothelial cells and extracellular matrix (ECM) proteins. Alteration of ECM composition and architecture is a hallmark feature of wound clot and tumor stroma. We previously reported that during angiogenesis, endothelial cell responses to growth factors are modulated by the compositional and mechanical properties of a surrounding three-dimensional (3D) extracellular matrix (ECM) that is dominated by either cross-linked fibrin or type I collagen. However, the role of 3D ECM in the regulation of angiogenesis associated with wound healing and tumor growth is not well defined. This study investigates the correlation of sprout angiogenesis and ECM microenvironment using in vivo and in vitro 3D angiogenesis models. It demonstrates that fibrin and type I collagen 3D matrices differentially but synergistically regulate sprout angiogenesis. Thus blocking both integrin alpha v beta 3 and integrin alpha 2 beta 1 might be a novel strategy to synergistically block sprout angiogenesis in solid tumors.

  5. Attachment of an aminoglycoside, amikacin, to implantable collagen for local delivery in wounds.

    PubMed Central

    Boyce, S T; Supp, A P; Warden, G D; Holder, I A

    1993-01-01

    Cultured skin substitutes consisting of implantable collagen (COL) and cultured human skin cells often fail clinically from destruction by microbial contamination. Hypothetically, addition of selected antimicrobial drugs to the implant may control microbial contamination and increase healing of skin wounds with these materials. As a model for drug delivery, bovine skin COL (1 mg/ml) and amikacin (AM; 46 micrograms/ml) were modified by covalent addition of biotin (B-COL and B-AM, respectively) from B-N-hydroxysuccinimide and bound together noncovalently with avidin (A). B-COL was incubated with A and then with B-peroxidase (B-P) or by serial incubation with B-AM and B-P, before P-dependent chromogen formation. Colorimetric data (n = 12 per condition) from spot tests on nitrocellulose paper were collected by transmission spectrophotometry. Specificity of drug binding in spot tests was determined by (i) serial dilution of B-COL; (ii) reactions with COL, AM, or P that had no B; (iii) removal of A; or (iv) preincubation of B-COL-A with B before incubation with B-P. Binding of B-AM was (i) dependent on the concentration of B-COL; (ii) specific to B-COL, A, and B-P (P < 0.05); and (iii) not eluted by incubation in 0.15 or 1.0 M NaCl. B-AM was found to block binding of B-P to the B-COL-A complex and to retain bacteriocidal activity against 10 clinical isolates of wound bacteria in the wet disc assay. Antimicrobial activity of B-AM was removed from solution by treatment with magnetic A and a permanent magnet. These results suggest that selected antimicrobial drugs can be biotinylated for attachments to COL-cultured cell implants without loss of pharmacologic activity. Because this chemistry utilizes a common ligand, any molar ratio of agents may be administered simultaneously and localized to the site of implantation. Images PMID:8239602

  6. Flexible Dermal Armor in Nature

    NASA Astrophysics Data System (ADS)

    Yang, Wen; Chen, Irene H.; Mckittrick, Joanna; Meyers, Marc A.

    2012-04-01

    Many animals possess dermal armor, which acts primarily as protection against predators. We illustrate this through examples from both our research and the literature: alligator, fish (alligator gar, arapaima, and Senegal bichir), armadillo, leatherback turtle, and a lizard, the Gila monster. The dermal armor in these animals is flexible and has a hierarchical structure with collagen fibers joining mineralized units (scales, tiles, or plates). This combination significantly increases the strength and flexibility in comparison with a simple monolithic mineral composite or rigid dermal armor. This dermal armor is being studied for future bioinspired armor applications providing increased mobility.

  7. Structural Alteration in Dermal Vessels and Collagen Bundles following Exposure of Skin Wound to Zeolite–Bentonite Compound

    PubMed Central

    Paydar, Shahram; Noorafshan, Ali; Jahanabadi, Shahram; Mortazavi, Seyed Mohammad Javad; Yahyavi, Seyedeh-Saeedeh; Khoshmohabat, Hadi

    2016-01-01

    Background. This study examines the impact of one-time direct application of haemostatic agent zeolite–bentonite powder to wounded skin on the healing process in rats. Materials and Methods. 24 male Sprague-Dawley rats were randomly allocated into two groups (n = 12): (1) the rats whose wounds were washed only with sterile normal saline (NS-treated) and (2) those treated with zeolite–bentonite compound (ZEO-treated). The wound was circular, full-thickness, and 2 cm in diameter. At the end of the 12th day, six animals from each group were randomly selected and terminated. The remaining rats were terminated after 21 days. Just after scarification, skin samples were excised and sent for stereological evaluation. Results. The results showed a significant difference between the two groups regarding the length density of the blood vessels and diameter of the large and small vessels on the 12th day after the wound was inflicted. Besides, volume density of both the dermis and collagen bundles was reduced by 25% in the ZEO-treated rats in comparison to the NS-treated animals after 21 days. Conclusions. One-time topical usage of zeolite–bentonite haemostatic powder on an animal skin wound might negatively affect the healing process through vasoconstriction and inhibition of neoangiogenesis. PMID:28116221

  8. In Vivo Magnetic Resonance Imaging of Type I Collagen Scaffold in Rat: Improving Visualization of Bladder and Subcutaneous Implants

    PubMed Central

    Sun, Yi; Geutjes, Paul; Oosterwijk, Egbert

    2014-01-01

    Noninvasive monitoring of implanted scaffolds is important to understand their behavior and role in tissue engineering, in particular to follow their degradation and interaction with host tissue. Magnetic resonance imaging (MRI) is well suited for this goal, but its application is often hampered by the low contrast of scaffolds that are prepared from biomaterials such as type I collagen. The aim of this study was to test iron oxide particles incorporation in improving their MRI contrasts, and to follow their degradation and tissue interactions. Scaffolds with and without iron oxide particles were implanted either subcutaneously or on the bladder of rats. At predetermined time points, in vivo MRI were obtained and tissues were then harvested for histology analysis and transmission electron microscopy. The result showed that the incorporation of iron oxide particles improved MRI contrast of the implants, providing information on their location, shapes, and degradation. Second, the host tissue reaction to the type I collagen implants could be observed in both MRI and histology. Finally, MRI also revealed that the degradation and host tissue reaction of iron particles-loaded scaffolds differed between subcutaneous and bladder implantation, which was substantiated by histology. PMID:24625324

  9. Immunohistochemical study of collagen types I and II and procollagen IIA in human cartilage repair tissue following autologous chondrocyte implantation.

    PubMed

    Roberts, S; Menage, J; Sandell, L J; Evans, E H; Richardson, J B

    2009-10-01

    This study has assessed the relative proportions of type I and II collagens and IIA procollagen in full depth biopsies of repair tissue in a large sample of patients treated with autologous chondrocyte implantation (ACI). Sixty five full depth biopsies were obtained from knees of 58 patients 8-60 months after treatment by ACI alone (n=55) or in combination with mosaicplasty (n=10). In addition articular cartilage was examined from eight individuals (aged 10-50) as controls. Morphology and semi-quantitative immunohistochemistry for collagen types I and II and procollagen IIA in the repair tissue were studied. Repair cartilage thickness was 2.89+/-1.5 mm and there was good basal integration between the repair cartilage, calcified cartilage and subchondral bone. Sixty five percent of the biopsies were predominantly fibrocartilage (mostly type I collagen and IIA procollagen), 15% were hyaline cartilage (mostly type II collagen), 17% were of mixed morphology and 3% were fibrous tissue (mostly type I collagen). Type II collagen and IIA procollagen were usually found in the lower regions near the bone and most type II collagen was present 30-60 months after treatment. The presence of type IIA procollagen in the repair tissue supports our hypothesis that this is indicative of a developing cartilage, with the ratio of type II collagen:procollagen IIA increasing from <2% in the first two years post-treatment to 30% three to five years after treatment. This suggests that cartilage repair tissue produced following ACI treatment, is likely to take some years to mature.

  10. Altered spatiotemporal expression of collagen types I, III, IV, and VI in Lpar3-deficient peri-implantation mouse uterus.

    PubMed

    Diao, Honglu; Aplin, John D; Xiao, Shuo; Chun, Jerold; Li, Zuguo; Chen, Shiyou; Ye, Xiaoqin

    2011-02-01

    Lpar3 is upregulated in the preimplantation uterus, and deletion of Lpar3 leads to delayed uterine receptivity in mice. Microarray analysis revealed that there was higher expression of Col3a1 and Col6a3 in the Preimplantation Day 3.5 Lpar3(-/-) uterus compared to Day 3.5 wild-type (WT) uterus. Since extracellular matrix (ECM) remodeling is indispensable during embryo implantation, and dynamic spatiotemporal alteration of specific collagen types is part of this process, this study aimed to characterize the expression of four main uterine collagen types: fibril-forming collagen (COL) I and COL III, basement membrane COL IV, and microfibrillar COL VI in the peri-implantation WT and Lpar3(-/-) uterus. An observed delay of COL III and COL VI clearance in the Lpar3(-/-) uterus may be associated with higher preimplantation expression of Col3a1 and Col6a3. There was also delayed clearance of COL I and delayed deposition of COL IV in the decidual zone in the Lpar3(-/-) uterus. These changes were different from the effects of 17beta-estradiol and progesterone on uterine collagen expression in ovariectomized WT uterus, indicating that the altered collagen expression in Lpar3(-/-) uterus is unlikely to be a result of alterations in ovarian hormones. Decreased expression of several genes encoding matrix-degrading metallo- and serine proteinases was observed in the Lpar3(-/-) uterus. These results demonstrate that pathways downstream of LPA3 are involved in the dynamic remodeling of ECM in the peri-implantation uterus.

  11. Collagen type-I leads to in vivo matrix mineralization and secondary stabilization of Mg-Zr-Ca alloy implants.

    PubMed

    Mushahary, Dolly; Wen, Cuie; Kumar, Jerald Mahesh; Lin, Jixing; Harishankar, Nemani; Hodgson, Peter; Pande, Gopal; Li, Yuncang

    2014-10-01

    Biodegradable magnesium-zirconia-calcium (Mg-Zr-Ca) alloy implants were coated with Collagen type-I (Coll-I) and assessed for their rate and efficacy of bone mineralization and implant stabilization. The phases, microstructure and mechanical properties of these alloys were analyzed using X-ray diffraction (XRD), optical microscopy and compression test, respectively, and the corrosion behavior was established by their hydrogen production rate in simulated body fluid (SBF). Coll-I extracted from rat tail, and characterized using fourier transform infrared (FT-IR) spectroscopy, was used for dip-coating the Mg-based alloys. The coated alloys were implanted into the femur bones of male New Zealand white rabbits. In vivo bone formation around the implants was quantified by measuring the bone mineral content/density (BMC/BMD) using dual-energy X-ray absorptiometry (DXA). Osseointegration of the implant and new bone mineralization was visualized by histological and immunohistochemical analysis. Upon surface coating with Coll-I, these alloys demonstrated high surface energy showing enhanced performance as an implant material that is suitable for rapid and efficient new bone tissue induction with optimal mineral content and cellular properties. The results demonstrate that Coll-I coated Mg-Zr-Ca alloys have a tendency to form superior trabecular bone structure with better osteoinduction around the implants and higher implant secondary stabilization, through the phenomenon of contact osteogenesis, compared to the control and uncoated ones in shorter periods of implantation. Hence, Coll-I surface coating of Mg-Zr-Ca alloys is a promising method for expediting new bone formation in vivo and enhancing osseointegration in load bearing implant applications.

  12. The Multi Centre Canadian Acellular Dermal Matrix Trial (MCCAT): study protocol for a randomized controlled trial in implant-based breast reconstruction

    PubMed Central

    2013-01-01

    Background The two-stage tissue expander/implant (TE/I) reconstruction is currently the gold standard method of implant-based immediate breast reconstruction in North America. Recently, however, there have been numerous case series describing the use of one-stage direct to implant reconstruction with the aid of acellular dermal matrix (ADM). In order to rigorously investigate the novel application of ADM in one-stage implant reconstruction, we are currently conducting a multicentre randomized controlled trial (RCT) designed to evaluate the impact on patient satisfaction and quality of life (QOL) compared to the two-stage TE/I technique. Methods/designs The MCCAT study is a multicenter Canadian ADM trial designed as a two-arm parallel superiority trial that will compare ADM-facilitated one-stage implant reconstruction compared to two-stage TE/I reconstruction following skin-sparing mastectomy (SSM) or nipple-sparing mastectomy (NSM) at 2 weeks, 6 months, and 12 months. The source population will be members of the mastectomy cohort with stage T0 to TII disease, proficient in English, over the age of 18 years, and planning to undergo SSM or NSM with immediate implant breast reconstruction. Stratified randomization will maintain a balanced distribution of important prognostic factors (study site and unilateral versus bilateral procedures). The primary outcome is patient satisfaction and QOL as measured by the validated and procedure-specific BREAST-Q. Secondary outcomes include short- and long-term complications, long-term aesthetic outcomes using five standardized photographs graded by three independent blinded observers, and a cost effectiveness analysis. Discussion There is tremendous interest in using ADM in implant breast reconstruction, particularly in the setting of one-stage direct to implant reconstruction where it was previously not possible without the intermediary use of a temporary tissue expander (TE). This unique advantage has led many patients and

  13. Transforming growth factor beta (TGF beta) causes a persistent increase in steady-state amounts of type I and type III collagen and fibronectin mRNAs in normal human dermal fibroblasts.

    PubMed Central

    Varga, J; Rosenbloom, J; Jimenez, S A

    1987-01-01

    It has been previously shown that transforming growth factor beta (TGF beta) is capable of stimulating fibroblast collagen and fibronectin biosynthesis. The purpose of this study was to examine the mechanisms involved in TGF beta stimulation of fibroblast biosynthetic activity. Our results indicate that TGF beta causes a marked enhancement of the production of types I and III collagens and fibronectin by cultured normal human dermal fibroblasts. The rate of collagen production by fibroblasts exposed to TGF beta was 2-3-fold greater than that of control cells. These effects were associated with a 2-3-fold increase in the steady-state amounts of types I and III collagen mRNAs and a 5-8-fold increase in the amounts of fibronectin mRNAs as determined by dot-blot hybridization with specific cloned cDNA probes. In addition, the increased production of collagen and fibronectin and the increased amounts of their corresponding mRNAs remained elevated for at least 72 h after removal of TGF beta. These findings suggest that TGF beta may play a major role in the normal regulation of extracellular matrix production in vivo and may contribute to the development of pathological states of fibrosis. Images Fig. 1. Fig. 4. PMID:3501287

  14. Permacol (porcine dermal collagen) and Alloderm (acellular cadaveric dermis) as a vascular patch repair for common carotid arteriotomy in a rabbit model.

    PubMed

    Tsai, John W; Ayubi, Farhan S; Rice, Robert D; Zhang, Zhou; Armstrong, Peter J

    2009-01-01

    Occult injuries to arteries are common in trauma and evolution of their repair has been observed throughout military conflicts. Currently, autogenous vein and polytetrafluoroethylene (PTFE) are used as patch agents for arterial trauma. However, suitable vein is often lacking in multitrauma patients, and PTFE is prone to infection in the contaminated combat wound. The purpose of this study is to evaluate Permacol, porcine dermal collagen, and Alloderm, acellular cadaveric dermis, as suitable alternatives to PTFE with the potential benefit of being used in contaminated wounds. A New Zealand White rabbit common carotid arteriotomy model was used to compare Permacol (n = 12), Alloderm (n = 11), and PTFE (n = 13) for patch repair. Thrombin generation was examined using an enzyme-linked immunosorbent assay for thrombin-antithrombin complex. Histological samples were taken to analyze vessel lumen area, vessel diameter, intimal thickness, and medial thickness. Pathological examinations were made to compare rates of intimal hyperplasia, aneurysm, patency, and thrombus formation. The Permacol group showed equivalent rates of thrombus, aneurysm, and patency compared with PTFE. Increased lumen area was seen in the Permacol group, 0.344 mm2 (p = 0.02) compared with the PTFE group, 0.204 mm2. Permacol also had decreased incidence of intimal hyperplasia compared with PTFE, 50.0% versus 92% (p < 0.05). Alloderm had increased rates of aneurysm formation, 63.6% (p = 0.004) compared with PTFE, 0.0%, and Permacol groups, 8.3%. Alloderm also had increased intimal thickness through the patch, 0.076 mm (p = 0.18), compared with PTFE, 0.026 mm, and Permacol groups, 0.024 mm. Vessel diameter through the patch showed the Alloderm group, 1.87 mm (p = 0.004), was significantly larger than both the Permacol, 1.41 mm, and PTFE groups, 1.28 mm. Furthermore, Alloderm showed leukocyte migration around the patch. Enzyme-linked immunosorbent assay for thrombin-antithrombin complex was only elevated

  15. The composition of engineered cartilage at the time of implantation determines the likelihood of regenerating tissue with a normal collagen architecture.

    PubMed

    Nagel, Thomas; Kelly, Daniel J

    2013-04-01

    The biomechanical functionality of articular cartilage is derived from both its biochemical composition and the architecture of the collagen network. Failure to replicate this normal Benninghoff architecture in regenerating articular cartilage may in turn predispose the tissue to failure. In this article, the influence of the maturity (or functionality) of a tissue-engineered construct at the time of implantation into a tibial chondral defect on the likelihood of recapitulating a normal Benninghoff architecture was investigated using a computational model featuring a collagen remodeling algorithm. Such a normal tissue architecture was predicted to form in the intact tibial plateau due to the interplay between the depth-dependent extracellular matrix properties, foremost swelling pressures, and external mechanical loading. In the presence of even small empty defects in the articular surface, the collagen architecture in the surrounding cartilage was predicted to deviate significantly from the native state, indicating a possible predisposition for osteoarthritic changes. These negative alterations were alleviated by the implantation of tissue-engineered cartilage, where a mature implant was predicted to result in the formation of a more native-like collagen architecture than immature implants. The results of this study highlight the importance of cartilage graft functionality to maintain and/or re-establish joint function and suggest that engineering a tissue with a native depth-dependent composition may facilitate the establishment of a normal Benninghoff collagen architecture after implantation into load-bearing defects.

  16. Characterization and evolution of dermal filaments from patients with Morgellons disease

    PubMed Central

    Middelveen, Marianne J; Mayne, Peter J; Kahn, Douglas G; Stricker, Raphael B

    2013-01-01

    Morgellons disease is an emerging skin disease characterized by formation of dermal filaments associated with multisystemic symptoms and tick-borne illness. Some clinicians hypothesize that these often colorful dermal filaments are textile fibers, either self-implanted by patients or accidentally adhering to lesions, and conclude that patients with this disease have delusions of infestation. We present histological observations and electron microscopic imaging from representative Morgellons disease samples revealing that dermal filaments in these cases are keratin and collagen in composition and result from proliferation and activation of keratinocytes and fibroblasts in the epidermis. Spirochetes were detected in the dermatological specimens from our study patients, providing evidence that Morgellons disease is associated with an infectious process. PMID:23326202

  17. Characterization and evolution of dermal filaments from patients with Morgellons disease.

    PubMed

    Middelveen, Marianne J; Mayne, Peter J; Kahn, Douglas G; Stricker, Raphael B

    2013-01-01

    Morgellons disease is an emerging skin disease characterized by formation of dermal filaments associated with multisystemic symptoms and tick-borne illness. Some clinicians hypothesize that these often colorful dermal filaments are textile fibers, either self-implanted by patients or accidentally adhering to lesions, and conclude that patients with this disease have delusions of infestation. We present histological observations and electron microscopic imaging from representative Morgellons disease samples revealing that dermal filaments in these cases are keratin and collagen in composition and result from proliferation and activation of keratinocytes and fibroblasts in the epidermis. Spirochetes were detected in the dermatological specimens from our study patients, providing evidence that Morgellons disease is associated with an infectious process.

  18. Successful treatment of complex traumatic and surgical wounds with a foetal bovine dermal matrix.

    PubMed

    Hayn, Ernesto

    2014-12-01

    A foetal bovine dermal repair scaffold (PriMatrix, TEI Biosciences) was used to treat complex surgical or traumatic wounds where the clinical need was to avoid skin flaps and to build new tissue in the wound that could be reepithelialised from the wound margins or closed with a subsequent application of a split-thickness skin graft (STSG). Forty-three consecutive cases were reviewed having an average size of 79·3 cm(2) , 50% of which had exposed tendon and/or bone. In a subset of wounds (44·7%), the implantation of the foetal dermal collagen scaffold was also augmented with negative pressure wound therapy (NPWT). Complete wound healing was documented in over 80% of the wounds treated, whether the wound was treated with the foetal bovine dermal scaffold alone (95·2%) or when supplemented with NPWT (82·4%). The scaffold successfully incorporated into wounds with exposed tendon and/or bone to build vascularised, dermal-like tissue. The new tissue in the wound supported STSGs however, in the majority of the cases (88·3%); wound closure was achieved through reepithelialisation of the incorporated dermal scaffold by endogenous wound keratinocytes. The foetal bovine dermal repair scaffold was found to offer an effective alternative treatment strategy for definitive closure of challenging traumatic or surgical wounds on patients who were not suitable candidates for tissue flaps.

  19. Tissue engineering of corneal stromal layer with dermal fibroblasts: phenotypic and functional switch of differentiated cells in cornea.

    PubMed

    Zhang, Yan Qing; Zhang, Wen Jie; Liu, Wei; Hu, Xiao Jie; Zhou, Guang Dong; Cui, Lei; Cao, Yilin

    2008-02-01

    Previously, we successfully engineered a corneal stromal layer using corneal stromal cells. However, the limited source and proliferation potential of corneal stromal cells has driven us to search for alternative cell sources for corneal stroma engineering. Based on the idea that the tissue-specific environment may alter cell fate, we proposed that dermal fibroblasts could switch their phenotype to that of corneal stromal cells in the corneal environment. Thus, dermal fibroblasts were harvested from newborn rabbits, seeded on biodegradable polyglycolic acid (PGA) scaffolds, cultured in vitro for 1 week, and then implanted into adult rabbit corneas. After 8 weeks of implantation, nearly transparent corneal stroma was formed, with a histological structure similar to that of its native counterpart. The existence of cells that had been retrovirally labeled with green fluorescence protein (GFP) demonstrated the survival of implanted cells. In addition, all GFP-positive cells that survived expressed keratocan, a specific marker for corneal stromal cells, and formed fine collagen fibrils with a highly organized pattern similar to that of native stroma. However, neither dermal fibroblast-PGA construct pre-incubated in vitro for 3 weeks nor chondrocyte-PGA construct could form transparent stroma. The results demonstrated that neonatal dermal fibroblasts could switch their phenotype in the new tissue environment under restricted conditions. The functional restoration of corneal transparency using dermal fibroblasts suggests that they could be an alternative cell source for corneal stroma engineering.

  20. A case report of semitendinosus tendon autograft for reconstruction of the meniscal wall supporting a collagen implant

    PubMed Central

    2013-01-01

    Purpose Describe the evolution of the reconstruction of meniscal rim with semitendinosus tendon in a patient with knee pain after a subtotal meniscectomy and absence of meniscal wall. Method 32 years old male with a six-month history of the left knee pain after a subtotal meniscectomy. The MRI indicated a small internal meniscal remainder without posterior horn attachment. Taking this absence as a relative contraindication for implant and meniscal transplantation, the reconstruction of a new meniscal wall with semitendinosus tendon autograft was considered. A collagen meniscal implant was attached to the new wall five months later. Results After two years the patient referred only non specific discomfort with full pain relief in the medial compartment. The MRI revealed integration of implants without significant degenerative changes compared to previous images. Conclusions This staged technique was designed to restore medial meniscus-like biologic tissue in a symptomatic patient following arthroscopic subtotal meniscectomy with a significant loss of the peripheral meniscus rim. Symptomatic improvement was obtained at two years follow-up. PMID:23557091

  1. Bilaminar Device of Poly(Lactic-co-Glycolic Acid)/Collagen Cultured With Adipose-Derived Stem Cells for Dermal Regeneration.

    PubMed

    Domingues, Juliana A; Cherutti, Giselle; Motta, Adriana C; Hausen, Moema A; Oliveira, Rômulo T D; Silva-Zacarin, Elaine C M; Barbo, Maria Lourdes P; Duek, Eliana A R

    2016-10-01

    Several materials are commercially available as substitutes for skin. However, new strategies are needed to improve the treatment of skin wounds. In this study, we developed and characterized a new device consisting of poly(lactic-co-glycolic acid) (PLGA) and collagen associated with mesenchymal stem cells derived from human adipose tissue. To develop the bilaminar device, we initially obtained a membrane of PLGA by dissolving the copolymer in chloroform and then produced a collagen type I scaffold by freeze-drying. The materials were characterized physically by gel permeation chromatography, scanning electron microscopy, and mass loss. Biological activity was assessed by cell proliferation assay. A preliminary study in vivo was performed with a pig model in which tissue regeneration was assessed macroscopically and histologically, the commercial device Integra being used as a control. The PLGA/collagen bilaminar material was porous, hydrolytically degradable, and compatible with skin growth. The polymer complex allowed cell adhesion and proliferation, making it a potentially useful cell carrier. In addition, the transparency of the material allowed monitoring of the lesion when the dressings were changed. Xenogeneic mesenchymal cells cultured on the device (PLGA/collagen/ASC) showed a reduced granulomatous reaction to bovine collagen, down-regulation of α-SMA, enhancement in the number of neoformed blood vessels, and collagen organization as compared with normal skin; the device was superior to other materials tested (PLGA/collagen and Integra) in its ability to stimulate the formation of new cutaneous tissue.

  2. Evaluation of 3D printed PCL/PLGA/β-TCP versus collagen membranes for guided bone regeneration in a beagle implant model.

    PubMed

    Won, J-Y; Park, C-Y; Bae, J-H; Ahn, G; Kim, C; Lim, D-H; Cho, D-W; Yun, W-S; Shim, J-H; Huh, J-B

    2016-10-07

    Here, we compared 3D-printed polycaprolactone/poly(lactic-co-glycolic acid)/β-tricalcium phosphate (PCL/PLGA/β-TCP) membranes with the widely used collagen membranes for guided bone regeneration (GBR) in beagle implant models. For mechanical property comparison in dry and wet conditions and cytocompatibility determination, we analyzed the rate and pattern of cell proliferation of seeded fibroblasts and preosteoblasts using the cell counting kit-8 assay and scanning electron microscopy. Osteogenic differentiation was verified using alizarin red S staining. At 8 weeks following implantation in vivo using beagle dogs, computed tomography and histological analyses were performed after sacrifice. Cell proliferation rates in vitro indicated that early cell attachment was higher in collagen than in PCL/PLGA/β-TCP membranes; however, the difference subsided by day 7. Similar outcomes were found for osteogenic differentiation, with approximately 2.5 times greater staining in collagen than PCL/PLGA/β-TCP, but without significant difference by day 14. In vivo, bone regeneration in the defect area, represented by new bone formation and bone-to-implant contact, paralleled those associated with collagen membranes. However, tensile testing revealed that whereas the PCL/PLGA/β-TCP membrane mechanical properties were conserved in both wet and dry states, the tensile property of collagen was reduced by 99% under wet conditions. Our results demonstrate in vitro and in vivo that PCL/PLGA/β-TCP membranes have similar levels of biocompatibility and bone regeneration as collagen membranes. In particular, considering that GBR is always applied to a wet environment (e.g. blood, saliva), we demonstrated that PCL/PLGA/β-TCP membranes maintained their form more reliably than collagen membranes in a wet setting, confirming their appropriateness as a GBR membrane.

  3. Expression in SPARC-null mice of collagen type I lacking the globular domain of the α1(I) N-propeptide results in abdominal hernias and loss of dermal collagen.

    PubMed

    Card, Lauren; Henderson, Nikki; Zhang, Yuhua; Bornstein, Paul; Bradshaw, Amy D

    2010-09-01

    The sequence encoding the N-propeptide of collagen I is characterized by significant conservation of amino acids across species; however, the function of the N-propeptide remains poorly defined. Studies in vitro have suggested that one activity of this propeptide might be to act as a feedback inhibitor of collagen I synthesis. To determine whether the N-propeptide contributed to decreased collagen content in SPARC-null mice, mice carrying a deletion of exon 2, which encodes the globular domain of the N-propeptide of collagen I, were crossed to SPARC-null animals. Mice lacking SPARC and expressing collagen I without the globular domain of the N-propeptide were viable and fertile. However, a significant number of animals developed abdominal hernias within the first 2 months of life with an approximate 20% penetrance (~35% of males). The dermis of SPARC-null/exon 2-deleted mice was thinner and contained fewer large collagen fibers in comparison with wild-type or in either single transgenic animal. The average collagen fibril diameter of exon 2-deleted mice did not significantly differ from wild-type mice (WT: 87.9 nm versus exon 2-deleted: 88.2 nm), whereas SPARC-null/exon 2-deleted fibrils were smaller than that of SPARC-null dermis (SPARC-null: 60.2 nm, SPARC-null/exon 2-deleted: 40.8 nm). As measured by hydroxyproline analysis, double transgenic skin biopsies contained significantly less collagen than those of wild-type, those of exon 2-deleted, and those of SPARC-null biopsies. Acetic acid extraction of collagen from skin biopsies revealed an increase in the proportion of soluble collagen in the SPARC-null/exon 2-deleted mice. These results support a function of the N-propeptide of collagen I in facilitating incorporation and stabilization of collagen I into the insoluble ECM and argue against a primary function of the N-propeptide as a negative regulator of collagen synthesis.

  4. Bone augmentation after ectopic implantation of a cell-free collagen-hydroxyapatite scaffold in the mouse

    PubMed Central

    Calabrese, Giovanna; Giuffrida, Raffaella; Forte, Stefano; Salvatorelli, Lucia; Fabbi, Claudia; Figallo, Elisa; Gulisano, Massimo; Parenti, Rosalba; Magro, Gaetano; Colarossi, Cristina; Memeo, Lorenzo; Gulino, Rosario

    2016-01-01

    The bone grafting is the classical way to treat large bone defects. Among the available techniques, autologous bone grafting is still the most used but, however, it can cause complications such as infection and donor site morbidity. Alternative and innovative methods rely on the development of biomaterials mimicking the structure and properties of natural bone. In this study, we characterized a cell-free scaffold, which was subcutaneously implanted in mice and then analyzed both in vivo and ex vivo after 1, 2, 4, 8 and 16 weeks, respectively. Two types of biomaterials, made of either collagen alone or collagen plus magnesium-enriched hydroxyapatite have been used. The results indicate that bone augmentation and angiogenesis could spontaneously occur into the biomaterial, probably by the recruitment of host cells, and that the composition of the scaffolds is crucial. In particular, the biomaterial more closely mimicking the native bone drives the process of bone augmentation more efficiently. Gene expression analysis and immunohistochemistry demonstrate the expression of typical markers of osteogenesis by the host cells populating the scaffold. Our data suggest that this biomaterial could represent a promising tool for the reconstruction of large bone defects, without using exogenous living cells or growth factors. PMID:27821853

  5. Biodegradable PTLGA Terpolymers versus Collagen Implants Used as an Adjuvant in Trabeculectomy in Rabbit Eye.

    PubMed

    Niu, Weiran; Shen, Guanglin; Yuan, Yuanzhi; Ma, Xiaoping; Li, Suming; Wang, Jingzhao; Fan, Zhongyong; Liao, Lan

    2015-01-01

    Purpose. To evaluate the effectiveness and safety of three biodegradable terpolymers prepared from L-lactide, trimethylene carbonate, and glycolide (PTLGA) as an aid for trabeculectomy compared with the Ologen (OLO). Methods. Trabeculectomy was carried out on rabbits with implantation made from OLO or three PTLGA terpolymers. Intraocular pressure (IOP) was recorded 1, 2, 3, and 6 months postoperatively and bleb evaluations were performed using ultrasound biomicroscopy (UBM) 3 months after surgery, optical coherence tomography (OCT) every month, and transmission electron microscopy (TEM) six months after surgery followed by histological examination 1, 2, 3, and 6 months postoperatively. Result. IOP was significantly reduced in all groups after surgery. There were no significant differences in the IOL between groups at any time after implantation. There was no significant difference between the groups examined by OCT, UBM, and TEM. Exposure of the implant was observed in one eye from the OLO group and one eye in the P1. Subconjunctiva hyperblastosis was observed in one eye from group P3 and two eyes from the OLO group. Conclusions. Subconjunctival implantation of filtering devices made from PTLGA may present a safe and effective additional surgical tool for the treatment of filtering surgery. Fewer complications were observed in the group with P2 implants compared to other groups.

  6. In vivo observation of age-related structural changes of dermal collagen in human facial skin using collagen-sensitive second harmonic generation microscope equipped with 1250-nm mode-locked Cr:Forsterite laser

    NASA Astrophysics Data System (ADS)

    Yasui, Takeshi; Yonetsu, Makoto; Tanaka, Ryosuke; Tanaka, Yuji; Fukushima, Shu-ichiro; Yamashita, Toyonobu; Ogura, Yuki; Hirao, Tetsuji; Murota, Hiroyuki; Araki, Tsutomu

    2013-03-01

    In vivo visualization of human skin aging is demonstrated using a Cr:Forsterite (Cr:F) laser-based, collagen-sensitive second harmonic generation (SHG) microscope. The deep penetration into human skin, as well as the specific sensitivity to collagen molecules, achieved by this microscope enables us to clearly visualize age-related structural changes of collagen fiber in the reticular dermis. Here we investigated intrinsic aging and/or photoaging in the male facial skin. Young subjects show dense distributions of thin collagen fibers, whereas elderly subjects show coarse distributions of thick collagen fibers. Furthermore, a comparison of SHG images between young and elderly subjects with and without a recent life history of excessive sun exposure show that a combination of photoaging with intrinsic aging significantly accelerates skin aging. We also perform image analysis based on two-dimensional Fourier transformation of the SHG images and extracted an aging parameter for human skin. The in vivo collagen-sensitive SHG microscope will be a powerful tool in fields such as cosmeceutical sciences and anti-aging dermatology.

  7. Relevant In Vitro Predictors of Human Acellular Dermal Matrix-Associated Inflammation and Capsule Formation in a Nonhuman Primate Subcutaneous Tissue Expander Model.

    PubMed

    Sandor, Maryellen; Leamy, Patrick; Assan, Pearl; Hoonjan, Amardeep; Huang, Li-Ting; Edwards, Marianne; Zuo, Wenqi; Li, Hui; Xu, Hui

    2017-01-01

    Objective: Benchtop methods were evaluated for preclinical inflammation/capsule formation correlation following implantation of human acellular dermal matrices. Methods: Dermal matrices were compared with native dermis for structure (histology, scanning electron microscopy), collagen solubility (hydroxyproline), enzymatic susceptibility (collagenase), and thermal stability (differential scanning calorimetry). Results were compared with implantation outcomes in a primate tissue expander model. Results: Native dermis, electron beam-sterilized, and freeze-dried human acellular dermal matrices had equivalent morphology, acid-soluble collagen (60.5% ± 6.3%, 65.3% ± 3.2%, and 63.3% ± 2.4%, respectively), and collagenase resistance. Implant results showed minimal inflammation/matrix degradation, lack of capsule formation, insignificant elastic modulus change (57.65 ± 20.24 MPa out-of-package/44.84 ± 23.87 MPa in vivo), and low antibody induction (2- to 8-fold increase) for electron beam-sterilized matrix. Similar results for freeze-dried dermal matrix were previously observed. γ-Irradiated, γ-irradiated/freeze-dried, and ethanol-stored dermal matrices were statistically different from native dermis for acid-soluble collagen (82.4% ± 5.8%, 72.2% ± 6.2%, and 76.8% ± 5.0%, respectively) and collagenase digestion rate, indicating matrix damage. γ-Irradiated matrix-implanted animals demonstrated elevated inflammatory response, foreign body giant cells, capsule formation at the tissue expander junction, and robust matrix metalloproteinase-1 staining with significant elastic modulus decrease (37.43 ± 7.52 MPa out-of-package/19.58 ± 1.16 MPa in vivo). Antibody increase (32- to 128-fold) was observed 6 to 10 weeks following γ-irradiated matrix implantation. Ethanol-stored dermal matrix elicited an acute antibody response (4- to 128-fold increase, 2-4 weeks) and macrophage-concentrated synovial-like hyperplasia at the tissue expander junction, moderate matrix

  8. Relevant In Vitro Predictors of Human Acellular Dermal Matrix-Associated Inflammation and Capsule Formation in a Nonhuman Primate Subcutaneous Tissue Expander Model

    PubMed Central

    Leamy, Patrick; Assan, Pearl; Hoonjan, Amardeep; Huang, Li-Ting; Edwards, Marianne; Zuo, Wenqi; Li, Hui; Xu, Hui

    2017-01-01

    Objective: Benchtop methods were evaluated for preclinical inflammation/capsule formation correlation following implantation of human acellular dermal matrices. Methods: Dermal matrices were compared with native dermis for structure (histology, scanning electron microscopy), collagen solubility (hydroxyproline), enzymatic susceptibility (collagenase), and thermal stability (differential scanning calorimetry). Results were compared with implantation outcomes in a primate tissue expander model. Results: Native dermis, electron beam–sterilized, and freeze-dried human acellular dermal matrices had equivalent morphology, acid-soluble collagen (60.5% ± 6.3%, 65.3% ± 3.2%, and 63.3% ± 2.4%, respectively), and collagenase resistance. Implant results showed minimal inflammation/matrix degradation, lack of capsule formation, insignificant elastic modulus change (57.65 ± 20.24 MPa out-of-package/44.84 ± 23.87 MPa in vivo), and low antibody induction (2- to 8-fold increase) for electron beam–sterilized matrix. Similar results for freeze-dried dermal matrix were previously observed. γ-Irradiated, γ-irradiated/freeze-dried, and ethanol-stored dermal matrices were statistically different from native dermis for acid-soluble collagen (82.4% ± 5.8%, 72.2% ± 6.2%, and 76.8% ± 5.0%, respectively) and collagenase digestion rate, indicating matrix damage. γ-Irradiated matrix-implanted animals demonstrated elevated inflammatory response, foreign body giant cells, capsule formation at the tissue expander junction, and robust matrix metalloproteinase-1 staining with significant elastic modulus decrease (37.43 ± 7.52 MPa out-of-package/19.58 ± 1.16 MPa in vivo). Antibody increase (32- to 128-fold) was observed 6 to 10 weeks following γ-irradiated matrix implantation. Ethanol-stored dermal matrix elicited an acute antibody response (4- to 128-fold increase, 2-4 weeks) and macrophage-concentrated synovial-like hyperplasia at the tissue expander junction, moderate matrix

  9. Almost Unilateral Focal Dermal Hypoplasia

    PubMed Central

    Lee, Solam; Choe, Sung Jay

    2017-01-01

    Focal dermal hypoplasia, caused by mutations in PORCN, is an X-linked ectodermal dysplasia, also known as Goltz syndrome. Only seven cases of unilateral or almost unilateral focal dermal hypoplasia have been reported in the English literature and there have been no previously reported cases in the Republic of Korea. A 19-year-old female presented with scalp defects, skin lesions on the right leg and the right trunk, and syndactyly of the right fourth and fifth toes. Cutaneous examination revealed multiple atrophic plaques and a brown and yellow mass with fat herniation and telangiectasia that was mostly located on the lower right leg. She had syndactyly on the right foot and the scalp lesion appeared to be an atrophic, membranous, fibrotic alopecic scar. A biopsy of the calf revealed upper dermal extension of fat cells, dermal atrophy, and loss of dermal collagen. A diagnosis of almost unilateral focal dermal hypoplasia was made on the basis of physical and histologic findings. Henceforth, the patient was referred to a plastic surgeon and an orthopedics department to repair her syndactyly. PMID:28223754

  10. Microporous Dermal-Like Electrospun Scaffolds Promote Accelerated Skin Regeneration

    PubMed Central

    Bonvallet, Paul P.; Culpepper, Bonnie K.; Bain, Jennifer L.; Schultz, Matthew J.; Thomas, Steven J.

    2014-01-01

    The goal of this study was to synthesize skin substitutes that blend native extracellular matrix (ECM) molecules with synthetic polymers which have favorable mechanical properties. To this end, scaffolds were electrospun from collagen I (col) and poly(ɛ-caprolactone) (PCL), and then pores were introduced mechanically to promote fibroblast infiltration, and subsequent filling of the pores with ECM. A 70:30 col/PCL ratio was determined to provide optimal support for dermal fibroblast growth, and a pore diameter, 160 μm, was identified that enabled fibroblasts to infiltrate and fill pores with native matrix molecules, including fibronectin and collagen I. Mechanical testing of 70:30 col/PCL scaffolds with 160 μm pores revealed a tensile strength of 1.4 MPa, and the scaffolds also exhibited a low rate of contraction (<19%). Upon implantation, scaffolds should support epidermal regeneration; we, therefore, evaluated keratinocyte growth on fibroblast-embedded scaffolds with matrix-filled pores. Keratinocytes formed a stratified layer on the surface of fibroblast-remodeled scaffolds, and staining for cytokeratin 10 revealed terminally differentiated keratinocytes at the apical surface. When implanted, 70:30 col/PCL scaffolds degraded within 3–4 weeks, an optimal time frame for degradation in vivo. Finally, 70:30 col/PCL scaffolds with or without 160 μm pores were implanted into full-thickness critical-sized skin defects. Relative to nonporous scaffolds or sham wounds, scaffolds with 160 μm pores induced accelerated wound closure, and stimulated regeneration of healthy dermal tissue, evidenced by a more normal-appearing matrix architecture, blood vessel in-growth, and hair follicle development. Collectively, these results suggest that microporous electrospun scaffolds are effective substrates for skin regeneration. PMID:24568584

  11. Microporous dermal-like electrospun scaffolds promote accelerated skin regeneration.

    PubMed

    Bonvallet, Paul P; Culpepper, Bonnie K; Bain, Jennifer L; Schultz, Matthew J; Thomas, Steven J; Bellis, Susan L

    2014-09-01

    The goal of this study was to synthesize skin substitutes that blend native extracellular matrix (ECM) molecules with synthetic polymers which have favorable mechanical properties. To this end, scaffolds were electrospun from collagen I (col) and poly(ɛ-caprolactone) (PCL), and then pores were introduced mechanically to promote fibroblast infiltration, and subsequent filling of the pores with ECM. A 70:30 col/PCL ratio was determined to provide optimal support for dermal fibroblast growth, and a pore diameter, 160 μm, was identified that enabled fibroblasts to infiltrate and fill pores with native matrix molecules, including fibronectin and collagen I. Mechanical testing of 70:30 col/PCL scaffolds with 160 μm pores revealed a tensile strength of 1.4 MPa, and the scaffolds also exhibited a low rate of contraction (<19%). Upon implantation, scaffolds should support epidermal regeneration; we, therefore, evaluated keratinocyte growth on fibroblast-embedded scaffolds with matrix-filled pores. Keratinocytes formed a stratified layer on the surface of fibroblast-remodeled scaffolds, and staining for cytokeratin 10 revealed terminally differentiated keratinocytes at the apical surface. When implanted, 70:30 col/PCL scaffolds degraded within 3-4 weeks, an optimal time frame for degradation in vivo. Finally, 70:30 col/PCL scaffolds with or without 160 μm pores were implanted into full-thickness critical-sized skin defects. Relative to nonporous scaffolds or sham wounds, scaffolds with 160 μm pores induced accelerated wound closure, and stimulated regeneration of healthy dermal tissue, evidenced by a more normal-appearing matrix architecture, blood vessel in-growth, and hair follicle development. Collectively, these results suggest that microporous electrospun scaffolds are effective substrates for skin regeneration.

  12. Microporous Dermal-Mimetic Electrospun Scaffolds Pre-Seeded with Fibroblasts Promote Tissue Regeneration in Full-Thickness Skin Wounds

    PubMed Central

    Bonvallet, Paul P.; Schultz, Matthew J.; Mitchell, Elizabeth H.; Bain, Jennifer L.; Culpepper, Bonnie K.; Thomas, Steven J.; Bellis, Susan L.

    2015-01-01

    Electrospun scaffolds serve as promising substrates for tissue repair due to their nanofibrous architecture and amenability to tailoring of chemical composition. In this study, the regenerative potential of a microporous electrospun scaffold pre-seeded with dermal fibroblasts was evaluated. Previously we reported that a 70% collagen I and 30% poly(Ɛ-caprolactone) electrospun scaffold (70:30 col/PCL) containing 160 μm diameter pores had favorable mechanical properties, supported fibroblast infiltration and subsequent cell-mediated deposition of extracellular matrix (ECM), and promoted more rapid and effective in vivo skin regeneration when compared to scaffolds lacking micropores. In the current study we tested the hypothesis that the efficacy of the 70:30 col/PCL microporous scaffolds could be further enhanced by seeding scaffolds with dermal fibroblasts prior to implantation into skin wounds. To address this hypothesis, a Fischer 344 (F344) rat syngeneic model was employed. In vitro studies showed that dermal fibroblasts isolated from F344 rat skin were able to adhere and proliferate on 70:30 col/PCL microporous scaffolds, and the cells also filled the 160 μm pores with native ECM proteins such as collagen I and fibronectin. Additionally, scaffolds seeded with F344 fibroblasts exhibited a low rate of contraction (~14%) over a 21 day time frame. To assess regenerative potential, scaffolds with or without seeded F344 dermal fibroblasts were implanted into full thickness, critical size defects created in F344 hosts. Specifically, we compared: microporous scaffolds containing fibroblasts seeded for 4 days; scaffolds containing fibroblasts seeded for only 1 day; acellular microporous scaffolds; and a sham wound (no scaffold). Scaffolds containing fibroblasts seeded for 4 days had the best response of all treatment groups with respect to accelerated wound healing, a more normal-appearing dermal matrix structure, and hair follicle regeneration. Collectively these

  13. Mechanical and biocompatible characterization of a cross-linked collagen-hyaluronic acid wound dressing.

    PubMed

    Kirk, James F; Ritter, Gregg; Finger, Isaac; Sankar, Dhyana; Reddy, Joseph D; Talton, James D; Nataraj, Chandra; Narisawa, Sonoko; Millán, José Luis; Cobb, Ronald R

    2013-01-01

    Collagen scaffolds have been widely employed as a dermal equivalent to induce fibroblast infiltrations and dermal regeneration in the treatment of chronic wounds and diabetic foot ulcers. Cross-linking methods have been developed to address the disadvantages of the rapid degradation associated with collagen-based scaffolds. To eliminate the potential drawbacks associated with glutaraldehyde cross-linking, methods using a water soluble carbodiimide have been developed. In the present study, the glycosaminoglycan (GAG) hyaluronic acid (HA), was covalently attached to an equine tendon derived collagen scaffold using 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) to create ntSPONGE The HA was shown to be homogeneously distributed throughout the collagen matrix. In vitro analyses of the scaffold indicated that the cross-linking enhanced the biological stability by decreasing the enzymatic degradation and increasing the thermal denaturation temperature. The material was shown to support the attachment and proliferation of mouse L929 fibroblast cells. In addition, the cross-linking decreased the resorption rate of the collagen as measured in an intramuscular implant model in rabbits. The material was also shown to be biocompatible in a variety of in vitro and in vivo assays. These results indicate that this cross-linked collagen-HA scaffold, ntSPONGE has the potential for use in chronic wound healing.

  14. A novel dermal matrix generated from burned skin as a promising substitute for deep-degree burns therapy.

    PubMed

    Yu, Guanying; Ye, Lan; Tan, Wei; Zhu, Xuguo; Li, Yaonan; Jiang, Duyin

    2016-03-01

    The extensive skin defects induced by severe burns are dangerous and can be fatal. Currently, the most common therapy is tangential excision to remove the necrotic or denatured areas of skin, followed by skin grafting. Xenogeneic dermal substitutes, such as porcine acellular dermal matrix (ADM), are typically used to cover the burn wounds, and may accelerate wound healing. It is assumed that burned skin that still maintains partial biological activity may be recycled to construct an autologous acellular dermal matrix, termed 'deep‑degree burned dermal matrix (DDBDM)'. In theory, DDBDM may avoid the histoincompatibility issues associated with foreign or xenogeneic dermal matrices, and reduce therapy costs by making full use of discarded skin. In the present study, the collagens within prepared DDBDM were thickened, disorganized and partially fractured, however, they still maintained their reticular structure and tensile strength (P<0.01). Through microarray analysis of the cytokines present in ADM and DDBDM, it was determined that the DDBDM did not produce excessive levels of harmful burn toxins. Following 4 weeks of subcutaneous implantation, ADM and DDBDM were incompletely degraded and maintained good integrity. No significant inflammatory reaction or rejection were observed, which indicated that ADM and DDBDM have good histocompatibility. Therefore, DDBDM may be a useful material for the treatment of deep‑degree burns.

  15. A novel dermal matrix generated from burned skin as a promising substitute for deep-degree burns therapy

    PubMed Central

    YU, GUANYING; YE, LAN; TAN, WEI; ZHU, XUGUO; LI, YAONAN; JIANG, DUYIN

    2016-01-01

    The extensive skin defects induced by severe burns are dangerous and can be fatal. Currently, the most common therapy is tangential excision to remove the necrotic or denatured areas of skin, followed by skin grafting. Xenogeneic dermal substitutes, such as porcine acellular dermal matrix (ADM), are typically used to cover the burn wounds, and may accelerate wound healing. It is assumed that burned skin that still maintains partial biological activity may be recycled to construct an autologous acellular dermal matrix, termed 'deep-degree burned dermal matrix (DDBDM)'. In theory, DDBDM may avoid the histoincompatibility issues associated with foreign or xenogeneic dermal matrices, and reduce therapy costs by making full use of discarded skin. In the present study, the collagens within prepared DDBDM were thickened, disorganized and partially fractured, however, they still maintained their reticular structure and tensile strength (P<0.01). Through microarray analysis of the cytokines present in ADM and DDBDM, it was determined that the DDBDM did not produce excessive levels of harmful burn toxins. Following 4 weeks of subcutaneous implantation, ADM and DDBDM were incompletely degraded and maintained good integrity. No significant inflammatory reaction or rejection were observed, which indicated that ADM and DDBDM have good histocompatibility. Therefore, DDBDM may be a useful material for the treatment of deep-degree burns. PMID:26846279

  16. Novel hydrogels based on carboxyl pullulan and collagen crosslinking with 1, 4-butanediol diglycidylether for use as a dermal filler: initial in vitro and in vivo investigations.

    PubMed

    Li, Xian; Xue, Wenjiao; Zhu, Chenhui; Fan, Daidi; Liu, Yannan; XiaoxuanMa

    2015-12-01

    Novel hydrogels based on carboxyl pullulan (PC) and human-like collagen (HLC) crosslinking with 1,4-butanediol diglycidyl ether (BDDE) are promising soft fillers for tissue engineering due to their highly tunable properties. Recent studies, however, have shown that incorporating hyaluronic acid and BDDE results in hydrogels with a microporous structure, a large pore size and high porosity, which reduce cell adhesion and enhance degradation in vivo. To improve biocompatibility and prevent biodegradation, the use of PC to replace hyaluronic acid in the fabrication of PC/BDDE (PCB) and PC/BDDE/HLC (PCBH) hydrogels was investigated. Preparation of gels with PC is a promising strategy due to the high reactivity, superb selectivity, and mild reaction conditions of PC. In particular, the Schiff base reaction of HLC and PC produces the novel functional group -RCONHR' in PCBH hydrogels. Twenty-four weeks after subcutaneous injection of either PCB or PCBH hydrogel in mice, the surrounding tissue inflammation, enzymatic response and cell attachment were better compared to hyaluronic acid-based hydrogels. However, the biocompatibility, cytocompatibility and non-biodegradability of PCBH were milder than those of the PCB hydrogels both in vivo and in vitro. These results show that the proposed use of PC and HLC for the fabrication of hydrogels is a promising strategy for generating soft filler for tissue engineering.

  17. Rapid onset of perfused blood vessels after implantation of ECFCs and MPCs in collagen, PuraMatrix and fibrin provisional matrices.

    PubMed

    Allen, Patrick; Kang, Kyu-Tae; Bischoff, Joyce

    2015-05-01

    We developed an in vivo vascularization model in which human endothelial colony-forming cells (ECFCs) and human mesenchymal progenitor cells (MPCs) form blood vessel networks when co-injected (ECFC + MPC) into nude mice in rat tail type I collagen, bovine fibrin or synthetic peptide PuraMatrix matrices. We used three approaches to determine the onset of functional vascularization when ECFC + MPC suspended in these matrices were implanted in vivo. The first was immunohistochemistry to detect vessels lined by human endothelial cells and filled with red blood cells. The second was in vivo vascular staining by tail vein injection of a mixture of Ulex europaeus agglutinin I (UEA-I), a lectin specific for human endothelium, and Griffonia simplicifolia isolectin B4 (GS-IB4 ), a lectin specific for rodent endothelium. The third approach employed contrast-enhanced ultrasound to measure the perfusion volumes of implants in individual animals over time. Human endothelial-lined tubular structures were detected in vivo on days 1 and 2 after implantation, with perfused human vessels detected on days 3 and 4. Contrast-enhanced ultrasound revealed significant perfusion of ECFC + MPC/collagen implants on days 1-4, at up to 14% perfused vascular volume. ECFC + MPC implanted in fibrin and PuraMatrix matrices also supported perfusion at day 1, as assessed by ultrasound (at 12% and 23% perfused vascular volume, respectively). This model demonstrates that ECFC + MPC suspended in any of the three matrices initiated a rapid onset of vascularization. We propose that ECFC + MPC delivered in vivo provide a means to achieve rapid perfusion of tissue-engineered organs or for in situ tissue repair.

  18. Epidermal cells adhere preferentially to type IV (basement membrane) collagen

    PubMed Central

    1979-01-01

    Epidermal cells from adult guinea pig skin attach and differentiate preferentially on substrates of type IV (basement membrane) collagen, compared to those of types I--III collagen. In contrast, guinea pig dermal fibroblasts attach equally well to all four collagen substrates. Fibronectin mediates the attachment of fibroblasts but not of epidermal cells to collagen. PMID:422650

  19. Occult peri-implant oroantral fistulae: posterior maxillary peri-implantitis/sinusitis of zygomatic or dental implant origin. Treatment and prevention with bone morphogenetic protein-2/absorbable collagen sponge sinus grafting.

    PubMed

    Jensen, Ole T; Adams, Mark; Cottam, Jared R; Ringeman, Jason

    2013-01-01

    Sinus floor grafting with bone morphogenetic protein-2 for transsinus implant placement or as a salvage technique for sinus-involved peri-implantitis has been found to be successful. Transsinus implants for All-on-Four treatment, zygomatic implants including quad zygomatics, and infected transsinus implants underwent peri-implant grafting, which was found to seal off the sinus cavity from the oral cavity in an effort to prevent or treat sinusitis/peri-implantitis.

  20. Reconstruction of the abdominal wall by using a combination of the human acellular dermal matrix implant and an interpositional omentum flap after extensive tumor resection in patients with abdominal wall neoplasm: A preliminary result

    PubMed Central

    Gu, Yan; Tang, Rui; Gong, Ding-Quan; Qian, Yun-Liang

    2008-01-01

    AIM: To present our trial using a combination of the human acellular dermal matrix (HADM) implant and an interpositional omentum flap to repair giant abdominal wall defects after extensive tumor resection. METHODS: Between February and October of 2007, three patients with giant defects of the abdominal wall after extensive tumor resection underwent reconstruction with a combination of HADM and omentum flap. Postoperative morbidities and signs of herniation were monitored. RESULTS: The abdominal wall reconstruction was successful in these three patients, there was no severe morbidity and no signs of herniation in the follow-up period. CONCLUSION: The combination of HADM and omentum flap offers a new, safe and effective alternative to traditional forms in the repair of giant abdominal wall defects. Further analysis of the long-term outcome and more cases are needed to assess the reliability of this technique. PMID:18205267

  1. Dermal exudate macrophages. Induction in dermal chambers and response to lymphokines.

    PubMed Central

    Goihman-Yahr, M; Ulrich, M; Noya-León, A; Rojas, A; Convit, J

    1975-01-01

    Chambers were implanted in the dorsum of guinea-pigs at the dermal-subcutaneous junction. Exudates were induced and harvested. Macrophages obtained were able to migrate in vitro. If procured from sensitized donors, macrophage migration was inhibited by the corresponding antigen. Dermal exudate macrophages are therefore subject to the effect of lymphokines. The chamber model may be useful for in vivo studies of cell to cell and cell-parasite interactions. PMID:1212821

  2. Structure of collagen adsorbed on a model implant surface resolved by polarization modulation infrared reflection-absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Brand, Izabella; Habecker, Florian; Ahlers, Michael; Klüner, Thorsten

    2015-03-01

    The polarization modulation infrared reflection-absorption spectra of collagen adsorbed on a titania surface and quantum chemical calculations are used to describe components of the amide I mode to the protein structure at a sub-molecular level. In this study, imino acid rich and poor fragments, representing the entire collagen molecule, are taken into account. The amide I mode of the collagen triple helix is composed of three absorption bands which involve: (i) (∼1690 cm-1) the Cdbnd O stretching modes at unhydrated groups, (ii) (1655-1673 cm-1) the Cdbnd O stretching at carbonyl groups at imino acids and glycine forming intramolecular hydrogen bonds with H atoms at both NH2 and, unusual for proteins, CH2 groups at glycine at a neighbouring chain and (iii) (∼1640 cm-1) the Cdbnd O stretching at carbonyl groups forming hydrogen bonds between two, often charged, amino acids as well as hydrogen bonds to water along the entire helix. The IR spectrum of films prepared from diluted solutions (c < 50 μg ml-1) corresponds to solution spectra indicating that native collagen molecules interact with water adsorbed on the titania surface. In films prepared from solutions (c ⩾ 50 μg ml-1) collagen multilayers are formed. The amide I mode is blue-shifted by 18 cm-1, indicating that intramolecular hydrogen bonds at imino acid rich fragments are weakened. Simultaneous red-shift of the amide A mode implies that the strength of hydrogen bonds at the imino acid poor fragments increases. Theoretically predicted distortion of the collagen structure upon adsorption on the titania surface is experimentally confirmed.

  3. Structure of collagen adsorbed on a model implant surface resolved by polarization modulation infrared reflection-absorption spectroscopy.

    PubMed

    Brand, Izabella; Habecker, Florian; Ahlers, Michael; Klüner, Thorsten

    2015-03-05

    The polarization modulation infrared reflection-absorption spectra of collagen adsorbed on a titania surface and quantum chemical calculations are used to describe components of the amide I mode to the protein structure at a sub-molecular level. In this study, imino acid rich and poor fragments, representing the entire collagen molecule, are taken into account. The amide I mode of the collagen triple helix is composed of three absorption bands which involve: (i) (∼1690cm(-1)) the CO stretching modes at unhydrated groups, (ii) (1655-1673cm(-1)) the CO stretching at carbonyl groups at imino acids and glycine forming intramolecular hydrogen bonds with H atoms at both NH2 and, unusual for proteins, CH2 groups at glycine at a neighbouring chain and (iii) (∼1640cm(-1)) the CO stretching at carbonyl groups forming hydrogen bonds between two, often charged, amino acids as well as hydrogen bonds to water along the entire helix. The IR spectrum of films prepared from diluted solutions (c<50μgml(-1)) corresponds to solution spectra indicating that native collagen molecules interact with water adsorbed on the titania surface. In films prepared from solutions (c⩾50μgml(-1)) collagen multilayers are formed. The amide I mode is blue-shifted by 18cm(-1), indicating that intramolecular hydrogen bonds at imino acid rich fragments are weakened. Simultaneous red-shift of the amide A mode implies that the strength of hydrogen bonds at the imino acid poor fragments increases. Theoretically predicted distortion of the collagen structure upon adsorption on the titania surface is experimentally confirmed.

  4. Reversibility of D-penicillamine induced collagen alterations in rat skin and granulation tissue.

    PubMed

    Junker, P; Lorenzen, I

    1983-06-01

    Granulation tissue was produced in rats by subcutaneous implantation of Visella sponges. D-penicillamine (D-pen) 100 or 500 mg/kg was administered daily for 42 days by gastric tubing. Pairfed, placebo treated animals were included as controls. Half of the groups were kept for additionally 28 days without medication. The inhibitory effect of D-pen on cross-link formation in newly synthesized collagen was readily reversible. By contrast, cross-link deficiency lasting beyond the observation period was observed in the higher polymeric collagen variants released by dilute acid, heat exposure or limited pepsin proteolysis as estimated by solubility, alpha/beta chain ratio and/or aldehyde content. By SDS-polyacrylamide gel electrophoresis on gels containing 3.6 M urea it was shown that purified dermal acid soluble collagen from treated animals consisted of a mixture of type I and III collagen, whereas only type I collagen was detected in controls. The band pattern was identical in reduced and unreduced collagen samples. Four weeks after D-pen discontinuance type III collagen had disappeared from the acid extract. Moreover, the ratio of type III to type I collagen in the pepsin digest from both granulation tissue and skin showed a persistent rise with D-pen. These observations indicate that D-pen destabilized type III collagen in particular by interference with its disulfide linkages. The amount of granulation tissue remained unaffected throughout the experiment, whereas the skin collagen content decreased at the higher dose level. The regeneration was not completed by the end of the observation period. Modulation of the molecular stability of granuloma collagens may be of relevance for the antirheumatoid effect of D-pen, but the sustained effect on normal tissues may imply a long standing impairment of their supportive capacity.

  5. Host tissue response by the expression of collagen to cyanoacrylate adhesives used in implant fixation for abdominal hernia repair.

    PubMed

    Pascual, Gemma; Rodríguez, Marta; Pérez-Köhler, Bárbara; Mesa-Ciller, Claudia; Fernández-Gutiérrez, Mar; San Román, Julio; Bellón, Juan M

    2017-04-01

    The less traumatic use of surgical adhesives rather than sutures for mesh fixation in hernia repair has started to gain popularity because they induce less host tissue damage and provoke less postoperative pain. This study examines the host tissue response to a new cyanoacrylate (CA) adhesive (n-octyl, OCA). Partial defects (3 × 5 cm) created in the rabbit anterior abdominal wall were repaired by mesh fixation using OCA, Glubran2(®)(n-butyl-CA), Ifabond(®)(n-hexyl-CA) or sutures. Samples were obtained at 14/90 days for morphology, collagens qRT-PCR/immunofluorescence and biomechanical studies. All meshes were successfully fixed. Seroma was detected mainly in the Glubran group at 14 days. Meshes fixed using all methods showed good host tissue incorporation. No signs of degradation of any of the adhesives were observed. At 14 days, collagen 1 and 3 mRNA expression levels were greater in the suture and OCA groups, and lower in Ifabond, with levels varying significantly in the latter group with respect to the others. By 90 days, expression levels had fallen in all groups, except for collagen 3 mRNA in Ifabond. Collagen I and III protein expression was marked in the suture and OCA groups at 90 days, but lower in Ifabond at both time points. Tensile strengths were similar across groups. Our findings indicate the similar behavior of the adhesives to sutures in terms of good tissue incorporation of the meshes and optimal repair zone strength. The lower seroma rate and similar collagenization to controls induced by OCA suggests its improved behavior over the other two glues. This article deals with a preclinical study to examine different aspects of the repair process in the host of three alkyl cyanoacrylates (n-butyl (GLUBRAN 2), n-hexyl (IFABOND), and n-octyl cyanoacrylate (EVOBOND)) compared to sutures (control), in the fixation of surgical meshes for hernia repair. It goes into detail about collagen deposition in the repair zone at short and medium term. The

  6. Evidence of healing of partial-thickness rotator cuff tears following arthroscopic augmentation with a collagen implant: a 2-year MRI follow-up

    PubMed Central

    Bokor, Desmond John; Sonnabend, David; Deady, Luke; Cass, Ben; Young, Allan; Van Kampen, Craig; Arnoczky, Steven

    2016-01-01

    Summary Background partial-thickness rotator cuff tears frequently enlarge due to increased local strain and often progress to full-thickness tears. Studies suggest the addition of new tendinous tissue to injured cuff tendons would significantly decrease peak strain, possibly protecting against tear progression. The aim of this study was to assess the ability of a highly-porous collagen implant to induce new tissue formation and limit tear progression when placed on the bursal surface of partial-thickness cuff tears. Methods following arthroscopic subacromial decompression, the implant was attached to the bursal surface of the supraspinatus tendon in a prospective series of 13 consecutive patients with intermediate – (3–6 mm) to high-grade (>6 mm) partial – thickness cuff tears (5 articular, 3 bursal, 5 intra-substance). Tendon thickness, defect size, and tendon quality were evaluated using magnetic resonance imaging (MRI) preoperatively and at 3, 6, 12, and 24 months postoperatively. Clinical outcomes were assessed using the Constant and American Shoulder and Elbow Society scores at the same preoperative and follow-up times. All 13 patients completed all follow-up exams (mean length of follow-up 27.0 months, range 23.3–32.0); no patients were lost to follow-up. Results the implant induced significant new tissue formation in all patients by 3 months (mean increase in tendon thickness 2.2 ± 0.26 mm). This tissue matured over time and became radiologically indistinguishable from the underlying tendon. The partial-thickness cuff tears showed consistent filling of the defects, with complete healing in 7 patients at 12 months, and a progressive improvement in tendon quality in the remaining patients. No tear progression was observed by MRI in any of the patients at 24 months. All clinical scores improved significantly over time. At 24 months, 12 of 13 patients (92%) had satisfactory or better results. Conclusions the results of this clinical study demonstrated

  7. The immunohistochemical and urodynamic evaluation towards the collagen-coated and non-coated polypropylene meshes implanted in the pelvic wall of the rats

    PubMed Central

    Lo, Tsia-Shu; Lin, Yi-Hao; Yusoff, Faridah Mohd; Chu, Hsiao-Chien; Hsieh, Wu-Chiao; Uy-Patrimonio, Ma. Clarissa

    2016-01-01

    Our aim is to study the inflammatory response towards the collagen-coated and non-coated polypropylene meshes in rats and the urodynamic investigation post-operatively. Forty-two female Sprague Dawley were divided into 7 groups of 6 rats; Control, Day 7 and 30 for Sham, Avaulta Plus (MPC), Perigee (MP). UDS were taken at days 7 and 30. Mesh with the vagina and bladder wall was removed and sent for immunohistochemical examination. Results showed intense inflammatory reaction on day 7 in the study groups which decreased on day 30. IL-1, TNF-α, MMP-2 and CD31 were observed to decrease from day 7 to day 30. NGF was almost normal on day 30 in all groups. UDS showed no difference in voiding pressure. Both Study and Sham groups had shorter voiding interval (VI) on day 7 but significantly lower in MPC. VI had significantly increased on day 30 in all groups. Voided volume was significantly lower in the mesh groups even when an increase was seen on day 30. In conclusion, the higher levels of IL-1, TNF-α and MMP-2 in collagen-coated polypropylene mesh imply greater inflammation than the non-coated polypropylene mesh. Mesh implantation can lead to shorter voiding interval and smaller bladder capacity. PMID:27991501

  8. PLLA-collagen and PLLA-gelatin hybrid scaffolds with funnel-like porous structure for skin tissue engineering

    NASA Astrophysics Data System (ADS)

    Lu, Hongxu; Oh, Hwan Hee; Kawazoe, Naoki; Yamagishi, Kozo; Chen, Guoping

    2012-12-01

    In skin tissue engineering, a three-dimensional porous scaffold is necessary to support cell adhesion and proliferation and to guide cells moving into the repair area in the wound healing process. Structurally, the porous scaffold should have an open and interconnected porous architecture to facilitate homogenous cell distribution. Moreover, the scaffolds should be mechanically strong to protect deformation during the formation of new skin. In this study, the hybrid scaffolds were prepared by forming funnel-like collagen or gelatin sponge on a woven poly(l-lactic acid) (PLLA) mesh. The hybrid scaffolds combined the advantages of both collagen or gelatin (good cell-interactions) and PLLA mesh (high mechanical strength). The hybrid scaffolds were used to culture dermal fibroblasts for dermal tissue engineering. The funnel-like porous structure promoted homogeneous cell distribution and extracellular matrix production. The PLLA mesh reinforced the scaffold to avoid deformation. Subcutaneous implantation showed that the PLLA-collagen and PLLA-gelatin scaffolds promoted the regeneration of dermal tissue and epidermis and reduced contraction during the formation of new tissue. These results indicate that funnel-like hybrid scaffolds can be used for skin tissue regeneration.

  9. Reversal of diabetes in mice with a bioengineered islet implant incorporating a type I collagen hydrogel and sustained release of vascular endothelial growth factor.

    PubMed

    Vernon, Robert B; Preisinger, Anton; Gooden, Michel D; D'Amico, Leonard A; Yue, Betty B; Bollyky, Paul L; Kuhr, Christian S; Hefty, Thomas R; Nepom, Gerald T; Gebe, John A

    2012-01-01

    We have developed a bioengineered implant (BI) to evaluate strategies to promote graft survival and function in models of islet transplantation in mice. The BI, sized for implantation within a fold of intestinal mesentery, consists of a disk-shaped, polyvinyl alcohol sponge infused with a type I collagen hydrogel that contains dispersed donor islets. To promote islet vascularization, the BI incorporates a spherical alginate hydrogel for sustained release of vascular endothelial growth factor (VEGF). BIs that contained 450-500 islets from syngeneic (C57Bl/6) donors and 20 ng of VEGF reversed streptozotocin (STZ)-induced diabetes in 100% of mice (8/8), whereas BIs that contained an equivalent number of islets, but which lacked VEGF, reversed STZ-induced diabetes in only 62.5% of mice (5/8). Between these "+VEGF" and "-VEGF" groups, the time to achieve normoglycemia (8-18 days after implantation) did not differ statistically; however, transitory, postoperative hypoglycemia was markedly reduced in the +VEGF group relative to the -VEGF group. Notably, none of the mice that achieved normoglycemia in these two groups required exogenous insulin therapy once the BIs began to fully regulate levels of blood glucose. Moreover, the transplanted mice responded to glucose challenge in a near-normal manner, as compared to the responses of healthy, nondiabetic (control) mice that had not received STZ. In future studies, the BIs described here will serve as platforms to evaluate the capability of immunomodulatory compounds, delivered locally within the BI, to prevent or reverse diabetes in the setting of autoimmune (type 1) diabetes.

  10. Reversal of Diabetes in Mice With a Bioengineered Islet Implant Incorporating a Type I Collagen Hydrogel and Sustained Release of Vascular Endothelial Growth Factor

    PubMed Central

    Vernon, Robert B.; Preisinger, Anton; Gooden, Michel D.; D’Amico, Leonard A.; Yue, Betty B.; Bollyky, Paul L.; Kuhr, Christian S.; Hefty, Thomas R.; Nepom, Gerald T.; Gebe, John A.

    2013-01-01

    We have developed a bioengineered implant (BI) to evaluate strategies to promote graft survival and function in models of islet transplantation in mice. The BI, sized for implantation within a fold of intestinal mesentery, consists of a disk-shaped, polyvinyl alcohol sponge infused with a type I collagen hydrogel that contains dispersed donor islets. To promote islet vascularization, the BI incorporates a spherical alginate hydrogel for sustained release of vascular endothelial growth factor (VEGF). BIs that contained 450–500 islets from syngeneic (C57Bl/6) donors and 20 ng of VEGF reversed streptozotocin (STZ)-induced diabetes in 100% of mice (8/8), whereas BIs that contained an equivalent number of islets, but which lacked VEGF, reversed STZ-induced diabetes in only 62.5% of mice (5/8). Between these “+VEGF” and “−VEGF” groups, the time to achieve normoglycemia (8–18 days after implantation) did not differ statistically; however, transitory, postoperative hypoglycemia was markedly reduced in the +VEGF group relative to the −VEGF group. Notably, none of the mice that achieved normoglycemia in these two groups required exogenous insulin therapy once the BIs began to fully regulate levels of blood glucose. Moreover, the transplanted mice responded to glucose challenge in a near-normal manner, as compared to the responses of healthy, nondiabetic (control) mice that had not received STZ. In future studies, the BIs described here will serve as platforms to evaluate the capability of immunomodulatory compounds, delivered locally within the BI, to prevent or reverse diabetes in the setting of autoimmune (type 1) diabetes. PMID:23231959

  11. Reconstruction of an Anterior Cervical Necrotizing Fasciitis Defect Using a Biodegradable Polyurethane Dermal Substitute

    PubMed Central

    Wagstaff, Marcus JD; Caplash, Yugesh

    2017-01-01

    Introduction: Although we have previously described the use of a novel polyurethane biodegradable dermal substitute in the reconstruction of 20 free flap donor sites, and extensive cutaneous defects, including a large area of exposed calvarium secondary to burn injury, our experience with this material now extends to 35 free flap donor site reconstructions and 13 major or complex burns. Methods: The polyurethane material (NovoSorb BTM; PolyNovo Biomaterials Pty Ltd, Port Melbourne, Victoria, Australia) was recently employed in another complex wound scenario, implanted into a large anterior cervical cutaneous and soft-tissue defect remaining after serial radical debridement for necrotizing fasciitis. Results: Implantation, integration, delamination, and split-skin graft application proceeded without complication, mirroring our previous experience in other wounds (including major burns). The result was a robust, supple, mobile, and well-contoured reconstruction over the deep tissues of the neck. The functional and cosmetic outcomes exceeded all expectation. Discussion: The wound environment created after necrotizing fasciitis infection and debridement is austere. In this particular case, reconstructive options were limited to large free flap repair, skin graft alone, and skin graft augmented by commercially available collagen/glycosaminoglycan dermal matrix. Each option was discarded for various reasons. Our previous success with NovoSorb BTM, developed at our center, prompted its use following regulatory approval. The patient was physiologically stronger after the temporization afforded by the biodegradable temporizing matrix over 4 weeks of integration. Conclusion: This is the first description of the successful use of an entirely synthetic biodegradable dermal substitute for the reconstruction of both necrotizing fasciitis and an anterior cervical defect. PMID:28197297

  12. Reconstruction of an Anterior Cervical Necrotizing Fasciitis Defect Using a Biodegradable Polyurethane Dermal Substitute.

    PubMed

    Wagstaff, Marcus Jd; Caplash, Yugesh; Greenwood, John E

    2017-01-01

    Introduction: Although we have previously described the use of a novel polyurethane biodegradable dermal substitute in the reconstruction of 20 free flap donor sites, and extensive cutaneous defects, including a large area of exposed calvarium secondary to burn injury, our experience with this material now extends to 35 free flap donor site reconstructions and 13 major or complex burns. Methods: The polyurethane material (NovoSorb BTM; PolyNovo Biomaterials Pty Ltd, Port Melbourne, Victoria, Australia) was recently employed in another complex wound scenario, implanted into a large anterior cervical cutaneous and soft-tissue defect remaining after serial radical debridement for necrotizing fasciitis. Results: Implantation, integration, delamination, and split-skin graft application proceeded without complication, mirroring our previous experience in other wounds (including major burns). The result was a robust, supple, mobile, and well-contoured reconstruction over the deep tissues of the neck. The functional and cosmetic outcomes exceeded all expectation. Discussion: The wound environment created after necrotizing fasciitis infection and debridement is austere. In this particular case, reconstructive options were limited to large free flap repair, skin graft alone, and skin graft augmented by commercially available collagen/glycosaminoglycan dermal matrix. Each option was discarded for various reasons. Our previous success with NovoSorb BTM, developed at our center, prompted its use following regulatory approval. The patient was physiologically stronger after the temporization afforded by the biodegradable temporizing matrix over 4 weeks of integration. Conclusion: This is the first description of the successful use of an entirely synthetic biodegradable dermal substitute for the reconstruction of both necrotizing fasciitis and an anterior cervical defect.

  13. CCN1 contributes to skin connective tissue aging by inducing age-associated secretory phenotype in human skin dermal fibroblasts.

    PubMed

    Quan, Taihao; Qin, Zhaoping; Robichaud, Patrick; Voorhees, John J; Fisher, Gary J

    2011-08-01

    Dermal connective tissue collagen is the major structural protein in skin. Fibroblasts within the dermis are largely responsible for collagen production and turnover. We have previously reported that dermal fibroblasts, in aged human skin in vivo, express elevated levels of CCN1, and that CCN1 negatively regulates collagen homeostasis by suppressing collagen synthesis and increasing collagen degradation (Quan et al. Am J Pathol 169:482-90, 2006, J Invest Dermatol 130:1697-706, 2010). In further investigations of CCN1 actions, we find that CCN1 alters collagen homeostasis by promoting expression of specific secreted proteins, which include matrix metalloproteinases and proinflammatory cytokines. We also find that CCN1-induced secretory proteins are elevated in aged human skin in vivo. We propose that CCN1 induces an "Age-Associated Secretory Phenotype", in dermal fibroblasts, which mediates collagen reduction and fragmentation in aged human skin.

  14. Collagen scaffolds loaded with collagen-binding NGF-beta accelerate ulcer healing.

    PubMed

    Sun, Wenjie; Lin, Hang; Chen, Bing; Zhao, Wenxue; Zhao, Yannan; Xiao, Zhifeng; Dai, Jianwu

    2010-03-01

    Studies have shown that exogenous nerve growth factor (NGF) accelerates ulcer healing, but the inefficient growth factor delivery system limits its clinical application. In this report, we found that the native human NGF-beta fused with a collagen-binding domain (CBD) could form a collagen-based NGF targeting delivery system, and the CBD-fused NGF-beta could bind to collagen membranes efficiently. Using the rabbit dermal ischemic ulcer model, we have found that this targeting delivery system maintains a higher concentration and stronger bioactivity of NGF-beta on the collagen membranes by promoting peripheral nerve growth. Furthermore, it enhances the rate of ulcer healing through accelerating the re-epithelialization of dermal ulcer wounds and the formation of capillary lumens within the newly formed tissue area. Thus, collagen membranes loaded with collagen-targeting human NGF-beta accelerate ulcer healing efficiently.

  15. Role of Age-Associated Alterations of the Dermal Extracellular Matrix Microenvironment in Human Skin Aging

    PubMed Central

    Quan, Taihao; Fisher, Gary J

    2015-01-01

    Human skin is largely composed of a collagen-rich connective tissue, which provides structural and functional support. The collagen-rich connective tissue is produced, organized, and maintained by dermal fibroblasts. During aging, dermal collagen fibrils undergo progressive loss and fragmentation, leading to thin and structurally weakened skin. Age-related alterations of collagen fibrils impairs skin structure and function and creates a tissue microenvironment that promotes age-related skin diseases, such as delayed wound healing and skin cancer development. This review describes cellular mechanisms that give rise to self-perpetuating, collagen fibril fragmentation that creates an age-associated dermal microenvironment (AADM), which contributes to decline of human skin function. PMID:25660807

  16. Development of oral and extra-oral endosseous craniofacial implants by using a mesh structure for connective tissue attachment.

    PubMed

    Mita, Atsushi; Yagihara, Atsushi; Wang, Wei; Takakuda, Kazuo

    2014-03-19

    Connective tissue attachment to a mesh structure incorporated on the surface of oral implants and extra-oral endosseous craniofacial implants (EOECI) was investigated. Two types of implants were prepared: TI and TI-Mesh. TI was composed of an upper and a lower component, both comprised of a titanium cylinder, which could be connected using a titanium screw. The composition of the TIMesh was similar, but the lower cylinder had a lateral groove that was covered with a titanium mesh. In animal experiments performed using rat calvaria, the lower component was first implanted and was left submerged for 3 weeks, then the upper component was mounted percutaneously. After an additional 2 weeks, each implant and the surrounding tissues were harvested and evaluated. Histological observations revealed collagen fibers originating from surrounding hypodermal tissues anchored to the mesh structures of the TI-Mesh whereas no such collagen fibers were observed around TI. Significantly greater values of the attachment strength, the thickness of the dermal tissue, the thickness of hypodermal tissue, and the attachment lengths were observed in TI-Mesh than those of TI. Thus connective tissue attachment with collagen fibers anchored to the mesh was achieved by incorporating mesh structures into the percutaneously placed implants.

  17. Complications of acellular dermal matrices in breast surgery.

    PubMed

    Israeli, Ron

    2012-11-01

    Acellular dermal matrices have been used in breast surgery for a decade. They are widely used in implant-based breast reconstruction to provide coverage of the inferolateral aspects of the prosthesis. Numerous benefits have been reported with this approach including improved fold control, better support and control of the implant pocket with concomitant reduced risk of malposition, and improved lower pole expansion. Seroma, infection, mastectomy skin necrosis, and expander/implant loss are the most commonly reported complications with this approach, and the incidences vary widely among studies. Patient selection and adherence to established intraoperative technique principles related to acellular dermal matrix use are both critical to minimizing the risk of complications. Acellular dermal matrices are also being used in aesthetic breast surgery, revision breast surgery, and nipple reconstruction, but clinical experience is limited. This article reviews the complications associated with the use of matrices in breast surgery from the published literature.

  18. Cysteine-rich protein 61 (CCN1) mediates replicative senescence-associated aberrant collagen homeostasis in human skin fibroblasts.

    PubMed

    Quan, Taihao; Qin, Zhaoping; Voorhees, John J; Fisher, Gary J

    2012-09-01

    Dermal fibroblasts produce a collagen-rich extracellular matrix, which confers mechanical strength and resiliency to human skin. During aging, collagen production is reduced and collagen fragmentation is increased, which is initiated by matrix metalloproteinase-1 (MMP-1). This aberrant collagen homeostasis results in net collagen deficiency, which impairs the structural integrity and function of skin. Cysteine-rich protein 61 (CCN1), a member of the CCN family, negatively regulates collagen homeostasis, in primary human skin dermal fibroblasts. As replicative senescence is a form of cellular aging, we have utilized replicative senescent dermal fibroblasts to further investigate the connection between elevated CCN1 and aberrant collagen homeostasis. CCN1 mRNA and protein levels were significantly elevated in replicative senescent dermal fibroblasts. Replicative senescent dermal fibroblasts also expressed significantly reduced levels of type I procollagen and increased levels of MMP-1. Knockdown of elevated CCN1 in senescent dermal fibroblasts partially normalized both type I procollagen and MMP-1 expression. These data further support a key role of CCN1 in regulation of collagen homeostasis. Elevated expression of CCN1 substantially increased collagen lattice contraction and fragmentation caused by replicative senescent dermal fibroblasts. Atomic force microscopy (AFM) further revealed collagen fibril fragmentation and disorganization were largely prevented by knockdown of CCN1 in replicative senescent dermal fibroblasts, suggesting CCN1 mediates MMP-1-induced alterations of collagen fibrils by replicative senescent dermal fibroblasts. Given the ability of CCN1 to regulate both production and degradation of type I collagen, it is likely that elevated-CCN1 functions as an important mediator of collagen loss, which is observed in aged human skin.

  19. Contribution of Fibroblasts to the Mechanical Stability of In Vitro Engineered Dermal-Like Tissue Through Extracellular Matrix Deposition

    PubMed Central

    Nair, Renjith P.; Joseph, Jasmin; Harikrishnan, V.S.; Krishnan, V.K.

    2014-01-01

    Abstract Tissue-engineered skin with mechanical and biological properties that match the native tissue could be a valuable graft to treat non-healing chronic wounds. Fibroblasts grown on a suitable biodegradable scaffold are a feasible strategy for the development of a dermal substitute above which epithelialization may occur naturally. Cell growth and phenotype maintenance are crucial to ensure the functional status of engineered tissue. In this study, an electrospun biodegradable polymer scaffold composed of a terpolymer PLGC [poly(lactide-glycolide-caprolactone)] with appropriate mechanical strength was used as a scaffold so that undesirable contraction of the wound could be prevented when it was implanted. To enhance cell growth, synthetic PLGC was incorporated with a fibrin-based biomimetic composite. The efficacy of the hybrid scaffold was evaluated by comparing it with bare PLGC in terms of fibroblast growth potential, extracellular matrix (ECM) deposition, polymer degradation, and mechanical strength. A significant increase was observed in fibroblast attachment, proliferation, and deposition of ECM proteins such as collagen and elastin in the hybrid scaffold. After growing fibroblasts for 20 d and 40 d, immunochemical staining of the decellularized scaffolds showed deposition of insoluble collagen and elastin on the hybrid scaffold but not on the bare scaffold. The loss of mechanical strength consequent to in vitro polymer degradation seemed to be balanced owing to the ECM deposition. Thus, tensile strength and elongation were better when cells were grown on the hybrid scaffold rather than the bare samples immersed in culture medium. Similar patterns of in vivo and in vitro degradation were observed during subcutaneous implantation and fibroblast culture, respectively. We therefore postulate that a hybrid scaffold comprising PLGC and fibrin is a potential candidate for the engineering of dermal tissue to be used in the regeneration of chronic wounds. PMID

  20. Dermal reflectivity determined by optical coherence tomography is an indicator of epidermal hyperplasia and dermal edema within inflamed skin

    NASA Astrophysics Data System (ADS)

    Phillips, Kevin G.; Wang, Yun; Levitz, David; Choudhury, Niloy; Swanzey, Emily; Lagowski, James; Kulesz-Martin, Molly; Jacques, Steven L.

    2011-04-01

    Psoriasis is a common inflammatory skin disease resulting from genetic and environmental alterations of cutaneous immune responses. While numerous therapeutic targets involved in the immunopathogenesis of psoriasis have been identified, the in vivo dynamics of inflammation in psoriasis remain unclear. We undertook in vivo time course focus-tracked optical coherence tomography (OCT) imaging to noninvasively document cutaneous alterations in mouse skin treated topically with Imiquimod (IMQ), an established model of a psoriasis-like disease. Quantitative appraisal of dermal architectural changes was achieved through a two parameter fit of OCT axial scans in the dermis of the form A(x, y, z) = ρ(x, y)exp [ - μ(x, y)z]. Ensemble averaging over 2000 axial scans per mouse in each treatment arm revealed no significant changes in the average dermal attenuation rate, <μ>, however the average local dermal reflectivity <ρ>, decreased significantly following 1, 3, and 6 days of IMQ treatment (p < 0.001) in comparison to vehicle-treated control mice. In contrast, epidermal and dermal thickness changes were only significant when comparing controls and 6-day IMQ treated mice. This suggests that dermal alterations, attributed to collagen fiber bundle enlargement, occur prior to epidermal thickness changes due to hyperplasia and dermal thickness changes due to edema. Dermal reflectivity positively correlated with epidermal hyperplasia (repi2 = 0.78) and dermal edema (rderm2 = 0.86). Our results suggest that dermal reflectivity as measured by OCT can be utilized to quantify a psoriasis-like disease in mice, and thus has the potential to aid in the quantitative assessment of psoriasis in humans.

  1. Age-related disruption of autophagy in dermal fibroblasts modulates extracellular matrix components

    SciTech Connect

    Tashiro, Kanae; Shishido, Mayumi; Fujimoto, Keiko; Hirota, Yuko; Yo, Kazuyuki; Gomi, Takamasa; Tanaka, Yoshitaka

    2014-01-03

    Highlights: •Autophagosomes accumulate in aged dermal fibroblasts. •Autophagic degradation is impaired in aged dermal fibroblasts. •Autophagy disruption affects extracellular matrix components in dermal fibroblasts. -- Abstract: Autophagy is an intracellular degradative system that is believed to be involved in the aging process. The contribution of autophagy to age-related changes in the human skin is unclear. In this study, we examined the relationship between autophagy and skin aging. Transmission electron microscopy and immunofluorescence microscopy analyses of skin tissue and cultured dermal fibroblasts derived from women of different ages revealed an increase in the number of nascent double-membrane autophagosomes with age. Western blot analysis showed that the amount of LC3-II, a form associated with autophagic vacuolar membranes, was significantly increased in aged dermal fibroblasts compared with that in young dermal fibroblasts. Aged dermal fibroblasts were minimally affected by inhibition of autophagic activity. Although lipofuscin autofluorescence was elevated in aged dermal fibroblasts, the expression of Beclin-1 and Atg5—genes essential for autophagosome formation—was similar between young and aged dermal fibroblasts, suggesting that the increase of autophagosomes in aged dermal fibroblasts was due to impaired autophagic flux rather than an increase in autophagosome formation. Treatment of young dermal fibroblasts with lysosomal protease inhibitors, which mimic the condition of aged dermal fibroblasts with reduced autophagic activity, altered the fibroblast content of type I procollagen, hyaluronan and elastin, and caused a breakdown of collagen fibrils. Collectively, these findings suggest that the autophagy pathway is impaired in aged dermal fibroblasts, which leads to deterioration of dermal integrity and skin fragility.

  2. Lipoid proteinosis: an inherited disorder of collagen metabolism?

    PubMed

    Harper, J I; Duance, V C; Sims, T J; Light, N D

    1985-08-01

    The dermal collagen of a patient with lipoid proteinosis was investigated by immunohistochemistry and biochemical analysis. The affected skin was found to contain significantly less collagen per unit dry weight than normal dermis but showed elevated levels of type 3 collagen with respect to type I. Purification of collagen types from affected skin after pepsin digestion showed no novel forms, but a doubling in the yield of type 5 collagen. These results correlated well with those of immunohistochemistry which showed a patchy, diffuse, widely distributed type 3 collagen and an increase in types 4 and 5 collagens associated with 'onion skin' endothelial basement membrane thickening. Estimation of collagen cross-links showed an abnormal pattern with a preponderance of the keto-imine form not normally associated with skin. These results strongly suggest that lipoid proteinosis involves a primary perturbation of collagen metabolism.

  3. Role of Age-Associated Alterations of the Dermal Extracellular Matrix Microenvironment in Human Skin Aging: A Mini-Review.

    PubMed

    Quan, Taihao; Fisher, Gary J

    2015-01-01

    Human skin is largely composed of a collagen-rich connective tissue, which provides structural and functional support. The collagen-rich connective tissue is produced, organized, and maintained by dermal fibroblasts. During aging, dermal collagen fibrils undergo progressive loss and fragmentation, leading to thin and structurally weakened skin. Age-related alterations of collagen fibrils impairs skin structure and function and creates a tissue microenvironment that promotes age-related skin diseases, such as delayed wound healing and skin cancer development. This mini-review describes cellular mechanisms that give rise to self-perpetuating, collagen fibril fragmentation that creates an age-associated dermal microenvironment, which contributes to decline of human skin function.

  4. Collagen telopeptides (cross-linking sites) play a role in collagen gel lattice contraction

    NASA Technical Reports Server (NTRS)

    Woodley, D. T.; Yamauchi, M.; Wynn, K. C.; Mechanic, G.; Briggaman, R. A.

    1991-01-01

    Solubilized interstitial collagens will form a fibrillar, gel-like lattice when brought to physiologic conditions. In the presence of human dermal fibroblasts the collagen lattice will contract. The rate of contraction can be determined by computer-assisted planemetry. The mechanisms involved in contraction are as yet unknown. Using this system it was found that the rate of contraction was markedly decreased when collagen lacking telopeptides was substituted for native collagen. Histidinohydroxylysinonorleucine (HHL) is a major stable trifunctional collagen cross-link in mature skin that involves a carboxyl terminal, telopeptide site 16c, the sixteenth amino acid residue from the carboxy terminal of the telopeptide region of alpha 1 (I) in type I collagen. Little, if any, HHL was present in native, purified, reconstituted, soluble collagen fibrils from 1% acetic acid-extracted 2-year-old bovine skin. In contrast, HHL cross-links were present (0.22 moles of cross-link per mole of collagen) in lattices of the same collagen contracted by fibroblasts. However, rat tail tendon does not contain HHL cross-links, and collagen lattices made of rat tail tendon collagen are capable of contraction. This suggests that telopeptide sites, and not mature HHL cross-links per se, are essential for fibroblasts to contract collagen lattices. Beta-aminopropionitrile fumarate (BAPN), a potent lathyrogen that perturbs collagen cross-linking by inhibition of lysyl oxidase, also inhibited the rate of lattice cell contraction in lattices composed of native collagen. However, the concentrations of BAPN that were necessary to inhibit the contraction of collagen lattices also inhibited fibroblast growth suggestive of cellular toxicity. In accordance with other studies, we found no inhibition of the rate of lattice contraction when fibronectin-depleted serum was used. Electron microscopy of contracted gels revealed typical collagen fibers with a characteristic axial periodicity. The data

  5. Dermal exposure assessment.

    PubMed

    Schneider, T; Cherrie, J W; Vermeulen, R; Kromhout, H

    2000-10-01

    Assessing dermal exposure is a complex task. Even the most commonly used methods face fundamental problems and there are large gaps in the documentation and validation of sampling methods. Still larger uncertainties exist regarding strategies for measurement. We propose a strategy based on a conceptual model and which draws on the considerable insight gained for airborne contaminants, including EN 689 for assessing exposure by inhalation. The vast amount of air sampling data has provided good insight into the statistical properties of short-term and long-term exposure levels, which is essential for designing cost-effective exposure studies. For surface and skin contaminants an understanding of the distribution types and parameter values is only beginning to emerge. Transport rates away from the skin contaminant layer determine the 'memory' of a dermal sample and measurement principles are proposed depending on these rates. It is argued that uptake is the ultimate dermal exposure metric for risk assessment and should be the basis for devising dermal occupational exposure limits.

  6. Histologic, Molecular, and Clinical Evaluation of Explanted Breast Prostheses, Capsules, and Acellular Dermal Matrices for Bacteria

    PubMed Central

    Poppler, Louis; Cohen, Justin; Dolen, Utku Can; Schriefer, Andrew E.; Tenenbaum, Marissa M.; Deeken, Corey; Chole, Richard A.; Myckatyn, Terence M.

    2015-01-01

    Background Subclinical infections, manifest as biofilms, are considered an important cause of capsular contracture. Acellular dermal matrices (ADMs) are frequently used in revision surgery to prevent recurrent capsular contractures. Objective We sought to identify an association between capsular contracture and biofilm formation on breast prostheses, capsules, and ADMs in a tissue expander/implant (TE/I) exchange clinical paradigm. Methods Biopsies of the prosthesis, capsule, and ADM from patients (N = 26) undergoing TE/I exchange for permanent breast implant were evaluated for subclinical infection. Capsular contracture was quantified with Baker Grade and intramammary pressure. Biofilm formation was evaluated with specialized cultures, rtPCR, bacterial taxonomy, live:dead staining, and scanning electron microscopy (SEM). Collagen distribution, capsular histology, and ADM remodeling were quantified following fluorescent and light microscopy. Results Prosthetic devices were implanted from 91 to 1115 days. Intramammary pressure increased with Baker Grade. Of 26 patients evaluated, one patient had a positive culture and one patient demonstrated convincing evidence of biofilm morphology on SEM. Following PCR amplification 5 samples randomly selected for 16S rRNA gene sequencing demonstrated an abundance of suborder Micrococcineae, consistent with contamination. Conclusions Our data suggest that bacterial biofilms likely contribute to a proportion, but not all diagnosed capsular contractures. Biofilm formation does not appear to differ significantly between ADMs or capsules. While capsular contracture remains an incompletely understood but common problem in breast implant surgery, advances in imaging, diagnostic, and molecular techniques can now provide more sophisticated insights into the pathophysiology of capsular contracture. Level of Evidence PMID:26229126

  7. Novel 11β-hydroxysteroid dehydrogenase 1 inhibitors reduce cortisol levels in keratinocytes and improve dermal collagen content in human ex vivo skin after exposure to cortisone and UV

    PubMed Central

    Geotti-Bianchini, Piero; Wandeler, Eliane; Kratschmar, Denise V.; Heidl, Marc; Campiche, Remo; Jackson, Eileen

    2017-01-01

    Activity and selectivity assessment of new bi-aryl amide 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) inhibitors, prepared in a modular manner via Suzuki cross-coupling, are described. Several compounds inhibiting 11β-HSD1 at nanomolar concentrations were identified. Compounds 2b, 3e, 7b and 12e were shown to selectively inhibit 11β-HSD1 over 11β-HSD2, 17β-HSD1 and 17β-HSD2. These inhibitors also potently inhibited 11β-HSD1 activity in intact HEK-293 cells expressing the recombinant enzyme and in intact primary human keratinocytes expressing endogenous 11β-HSD1. Moreover, compounds 2b, 3e and 12e were tested for their activity in human skin biopsies. They were able to prevent, at least in part, both the cortisone- and the UV-mediated decreases in collagen content. Thus, inhibition of 11β-HSD1 by these compounds can be further investigated to delay or prevent UV-mediated skin damage and skin aging. PMID:28152550

  8. Biological effects of glycolic acid on dermal matrix metabolism mediated by dermal fibroblasts and epidermal keratinocytes.

    PubMed

    Okano, Yuri; Abe, Yumiko; Masaki, Hitoshi; Santhanam, Uma; Ichihashi, Masamitsu; Funasaka, Yoko

    2003-01-01

    Glycolic acid (GA), one of the alpha-hydroxy acids, is widely used as an agent for chemical peeling. Although there are several reports about the clinical effects of GA in the literature, its biological mechanism remains mostly unclear, and there are only a few reports about its effects on skin rejuvenation mediated by keratinocytes. The aim of this study was to investigate the effect of GA on the dermal matrix metabolism of keratinocytes and fibroblasts using in vitro and ex vivo systems. Our study shows that GA not only directly accelerates collagen synthesis by fibroblasts, but it also modulates matrix degradation and collagen synthesis through keratinocyte-released cytokines. We confirm that IL-1alpha is one of the primary mediators for matrix degradation released from keratinocytes after GA treatment. These results suggest that GA contributes to the recovery of photodamaged skin through various actions, depending on the skin cell type.

  9. Defining dermal adipose tissue.

    PubMed

    Driskell, Ryan R; Jahoda, Colin A B; Chuong, Cheng-Ming; Watt, Fiona M; Horsley, Valerie

    2014-09-01

    Here, we explore the evolution and development of skin-associated adipose tissue with the goal of establishing nomenclature for this tissue. Underlying the reticular dermis, a thick layer of adipocytes exists that encases mature hair follicles in rodents and humans. The association of lipid-filled cells with the skin is found in many invertebrate and vertebrate species. Historically, this layer of adipocytes has been termed subcutaneous adipose, hypodermis and subcutis. Recent data have revealed a common precursor for dermal fibroblasts and intradermal adipocytes during development. Furthermore, the development of adipocytes in the skin is independent from that of subcutaneous adipose tissue development. Finally, the role of adipocytes has been shown to be relevant for epidermal homoeostasis during hair follicle regeneration and wound healing. Thus, we propose a refined nomenclature for the cells and adipose tissue underlying the reticular dermis as intradermal adipocytes and dermal white adipose tissue, respectively.

  10. Alteration of Skin Properties with Autologous Dermal Fibroblasts

    PubMed Central

    Thangapazham, Rajesh L.; Darling, Thomas N.; Meyerle, Jon

    2014-01-01

    Dermal fibroblasts are mesenchymal cells found between the skin epidermis and subcutaneous tissue. They are primarily responsible for synthesizing collagen and glycosaminoglycans; components of extracellular matrix supporting the structural integrity of the skin. Dermal fibroblasts play a pivotal role in cutaneous wound healing and skin repair. Preclinical studies suggest wider applications of dermal fibroblasts ranging from skin based indications to non-skin tissue regeneration in tendon repair. One clinical application for autologous dermal fibroblasts has been approved by the Food and Drug Administration (FDA) while others are in preclinical development or various stages of regulatory approval. In this context, we outline the role of fibroblasts in wound healing and discuss recent advances and the current development pipeline for cellular therapies using autologous dermal fibroblasts. The microanatomic and phenotypic differences of fibroblasts occupying particular locations within the skin are reviewed, emphasizing the therapeutic relevance of attributes exhibited by subpopulations of fibroblasts. Special focus is provided to fibroblast characteristics that define regional differences in skin, including the thick and hairless skin of the palms and soles as compared to hair-bearing skin. This regional specificity and functional identity of fibroblasts provides another platform for developing regional skin applications such as the induction of hair follicles in bald scalp or alteration of the phenotype of stump skin in amputees to better support their prosthetic devices. PMID:24828202

  11. Alteration of skin properties with autologous dermal fibroblasts.

    PubMed

    Thangapazham, Rajesh L; Darling, Thomas N; Meyerle, Jon

    2014-05-13

    Dermal fibroblasts are mesenchymal cells found between the skin epidermis and subcutaneous tissue. They are primarily responsible for synthesizing collagen and glycosaminoglycans; components of extracellular matrix supporting the structural integrity of the skin. Dermal fibroblasts play a pivotal role in cutaneous wound healing and skin repair. Preclinical studies suggest wider applications of dermal fibroblasts ranging from skin based indications to non-skin tissue regeneration in tendon repair. One clinical application for autologous dermal fibroblasts has been approved by the Food and Drug Administration (FDA) while others are in preclinical development or various stages of regulatory approval. In this context, we outline the role of fibroblasts in wound healing and discuss recent advances and the current development pipeline for cellular therapies using autologous dermal fibroblasts. The microanatomic and phenotypic differences of fibroblasts occupying particular locations within the skin are reviewed, emphasizing the therapeutic relevance of attributes exhibited by subpopulations of fibroblasts. Special focus is provided to fibroblast characteristics that define regional differences in skin, including the thick and hairless skin of the palms and soles as compared to hair-bearing skin. This regional specificity and functional identity of fibroblasts provides another platform for developing regional skin applications such as the induction of hair follicles in bald scalp or alteration of the phenotype of stump skin in amputees to better support their prosthetic devices.

  12. Human acellular dermal matrix grafts for rhinoplasty.

    PubMed

    Sherris, David A; Oriel, Brad S

    2011-09-01

    Rhinoplasty often relies on graft material for structural support in the form of cartilage, bone grafts, or fascia. In addition, pliable grafts are often helpful for contouring and can function as a barrier. Unfortunately, grafts carry the disadvantage of requiring an additional donor site, with associated complications. Human acellular dermal matrix (ADM) biological implants offer an exciting alternative for structural support and nonstructural implantation in rhinoplasty procedures. To examine the efficacy of ADM placement in rhinoplasty and septoplasty, the authors report the results from a series of 51 patients. In this series, there were no cases of infection, skin discoloration, seroma formation, septal perforation, significant resorption, extrusion, or other complications related to ADM placement. Therefore, the authors believe that ADM offers a safe and effective alternative to traditional grafting methods for functional and aesthetic rhinoplasty.

  13. Collagen for bone tissue regeneration.

    PubMed

    Ferreira, Ana Marina; Gentile, Piergiorgio; Chiono, Valeria; Ciardelli, Gianluca

    2012-09-01

    In the last decades, increased knowledge about the organization, structure and properties of collagen (particularly concerning interactions between cells and collagen-based materials) has inspired scientists and engineers to design innovative collagen-based biomaterials and to develop novel tissue-engineering products. The design of resorbable collagen-based medical implants requires understanding the tissue/organ anatomy and biological function as well as the role of collagen's physicochemical properties and structure in tissue/organ regeneration. Bone is a complex tissue that plays a critical role in diverse metabolic processes mediated by calcium delivery as well as in hematopoiesis whilst maintaining skeleton strength. A wide variety of collagen-based scaffolds have been proposed for different tissue engineering applications. These scaffolds are designed to promote a biological response, such as cell interaction, and to work as artificial biomimetic extracellular matrices that guide tissue regeneration. This paper critically reviews the current understanding of the complex hierarchical structure and properties of native collagen molecules, and describes the scientific challenge of manufacturing collagen-based materials with suitable properties and shapes for specific biomedical applications, with special emphasis on bone tissue engineering. The analysis of the state of the art in the field reveals the presence of innovative techniques for scaffold and material manufacturing that are currently opening the way to the preparation of biomimetic substrates that modulate cell interaction for improved substitution, restoration, retention or enhancement of bone tissue function.

  14. Genetics Home Reference: focal dermal hypoplasia

    MedlinePlus

    ... Home Health Conditions focal dermal hypoplasia focal dermal hypoplasia Enable Javascript to view the expand/collapse boxes. ... PDF Open All Close All Description Focal dermal hypoplasia is a genetic disorder that primarily affects the ...

  15. Bioengineered collagens

    PubMed Central

    Ramshaw, John AM; Werkmeister, Jerome A; Dumsday, Geoff J

    2014-01-01

    Mammalian collagen has been widely used as a biomedical material. Nevertheless, there are still concerns about the variability between preparations, particularly with the possibility that the products may transmit animal-based diseases. Many groups have examined the possible application of bioengineered mammalian collagens. However, translating laboratory studies into large-scale manufacturing has often proved difficult, although certain yeast and plant systems seem effective. Production of full-length mammalian collagens, with the required secondary modification to give proline hydroxylation, has proved difficult in E. coli. However, recently, a new group of collagens, which have the characteristic triple helical structure of collagen, has been identified in bacteria. These proteins are stable without the need for hydroxyproline and are able to be produced and purified from E. coli in high yield. Initial studies indicate that they would be suitable for biomedical applications. PMID:24717980

  16. UV-Induced Triggering of a Biomechanical Initiation Switch Within Collagen Promotes Development of a Melanoma-Permissive Microenvironment in the Skin

    DTIC Science & Technology

    2011-09-01

    Using similar experimental approaches we coated microtiter wells with UVA or UVB irradiated collagen type-I or type-IV and examined human dermal ...4). Human dermal fibroblast cell adhesion to collagen type-I was only minimally (20%-25%) enhanced following UVA or UVB irradiation, while high dose...findings suggest that UVA and UVB dose dependently and differentially trigger conformational changes in collagen type-I and IV resulting in the

  17. Cutaneous and inflammatory response to long-term percutaneous implants of sphere-templated porous/solid poly(HEMA) and silicone in mice.

    PubMed

    Fleckman, Philip; Usui, Marcia; Zhao, Ge; Underwood, Robert; Maginness, Max; Marshall, Andrew; Glaister, Christine; Ratner, Buddy; Olerud, John

    2012-05-01

    This study investigates mouse cutaneous responses to long-term percutaneously implanted rods surrounded by sphere-templated porous biomaterials engineered to mimic medical devices surrounded by a porous cuff. We hypothesized that keratinocytes would migrate through the pores and stop, permigrate, or marsupialize along the porous/solid interface. Porous/solid-core poly(2-hydroxyethyl methacrylate) [poly(HEMA)] and silicone rods were implanted in mice for 14 days, and for 1, 3, and 6 months. Implants with surrounding tissue were analyzed (immuno)histochemically by light microscopy. Poly(HEMA)/skin implants yielded better morphologic data than silicone implants. Keratinocytes at the poly(HEMA) interface migrated in two different directions. "Ventral" keratinocytes contiguous with the dermal-epidermal junction migrated into the outermost pores, forming an integrated collar surrounding the rods. "Dorsal" keratinocytes appearing to emanate from the differentiated epithelial layer, extended upward along and into the exterior portion of the rod, forming an integrated sheath. Leukocytes persisted in poly(HEMA) and silicone pores for the duration of the study. Vascular and collagen networks within the poly(HEMA) pores matured as a function of time up to 3-months implantation. Nerves were not observed within the pores. Poly(HEMA) underwent morphological changes by 6 months of implantation. Marsupialization, foreign body encapsulation, and infection were not observed in any implants.

  18. Dermal Lipogenesis Inhibits Adiponectin Production in Human Dermal Fibroblasts while Exogenous Adiponectin Administration Prevents against UVA-Induced Dermal Matrix Degradation in Human Skin

    PubMed Central

    Fang, Chien-Liang; Huang, Ling-Hung; Tsai, Hung-Yueh; Chang, Hsin-I

    2016-01-01

    Adiponectin is one of the most abundant adipokines from the subcutaneous fat, and regulates multiple activities through endocrine, paracrine, or autocrine mechanisms. However, its expression in adipogenic induced fibroblasts, and the potential role in photoaging has not been determined. Here, human dermal fibroblasts, Hs68, were presented as a cell model of dermal lipogenesis through stimulation of adipogenic differentiation medium (ADM). Similar to other studies in murine pre-adipocyte models (i.e., 3T3-L1), Hs68 fibroblasts showed a tendency to lipogenesis based on lipid accumulation, triglyceride formation, and the expressions of PPAR-γ, lipoprotein lipase (LPL), and FABP4 mRNA. As expected, ADM-treated fibroblasts displayed a reduction on adiponectin expression. Next, we emphasized the photoprotective effects of adiponectin against UVA-induced damage in Hs68 fibroblasts. UVA radiation can downregulate cell adhesion strength and elastic modulus of Hs68 fibroblasts. Moreover, UVA radiation could induce the mRNA expressions of epidermal growth factor receptor (EGFR), adiponectin receptor 1 (AdipoR1), matrix metalloproteinase-1 (MMP-1), MMP-3, and cyclooxygenase-2 (COX-2), but downregulate the mRNA expressions of type I and type III collagen. On the other hand, post-treatment of adiponectin can partially overcome UVA-induced reduction in the cell adhesion strength of Hs68 fibroblasts through the activation of AdipoR1 and the suppression of EGF-R. In addition, post-treatment of adiponectin indicated the increase of type III collagen and elastin mRNA expression and the decrease of MMP-1 and MMP-3 mRNA expression, but a limited degree of recovery of elastic modulus on UVA-irradiated Hs68 fibroblasts. Overall, these results suggest that dermal lipogenesis may inhibit the expression of adiponectin while exogenous adiponectin administration prevents against UVA-induced dermal matrix degradation in Hs68 fibroblasts. PMID:27428951

  19. Dermal Lipogenesis Inhibits Adiponectin Production in Human Dermal Fibroblasts while Exogenous Adiponectin Administration Prevents against UVA-Induced Dermal Matrix Degradation in Human Skin.

    PubMed

    Fang, Chien-Liang; Huang, Ling-Hung; Tsai, Hung-Yueh; Chang, Hsin-I

    2016-07-14

    Adiponectin is one of the most abundant adipokines from the subcutaneous fat, and regulates multiple activities through endocrine, paracrine, or autocrine mechanisms. However, its expression in adipogenic induced fibroblasts, and the potential role in photoaging has not been determined. Here, human dermal fibroblasts, Hs68, were presented as a cell model of dermal lipogenesis through stimulation of adipogenic differentiation medium (ADM). Similar to other studies in murine pre-adipocyte models (i.e., 3T3-L1), Hs68 fibroblasts showed a tendency to lipogenesis based on lipid accumulation, triglyceride formation, and the expressions of PPAR-γ, lipoprotein lipase (LPL), and FABP4 mRNA. As expected, ADM-treated fibroblasts displayed a reduction on adiponectin expression. Next, we emphasized the photoprotective effects of adiponectin against UVA-induced damage in Hs68 fibroblasts. UVA radiation can downregulate cell adhesion strength and elastic modulus of Hs68 fibroblasts. Moreover, UVA radiation could induce the mRNA expressions of epidermal growth factor receptor (EGFR), adiponectin receptor 1 (AdipoR1), matrix metalloproteinase-1 (MMP-1), MMP-3, and cyclooxygenase-2 (COX-2), but downregulate the mRNA expressions of type I and type III collagen. On the other hand, post-treatment of adiponectin can partially overcome UVA-induced reduction in the cell adhesion strength of Hs68 fibroblasts through the activation of AdipoR1 and the suppression of EGF-R. In addition, post-treatment of adiponectin indicated the increase of type III collagen and elastin mRNA expression and the decrease of MMP-1 and MMP-3 mRNA expression, but a limited degree of recovery of elastic modulus on UVA-irradiated Hs68 fibroblasts. Overall, these results suggest that dermal lipogenesis may inhibit the expression of adiponectin while exogenous adiponectin administration prevents against UVA-induced dermal matrix degradation in Hs68 fibroblasts.

  20. Characterization of acellular dermal matrices (ADMs) prepared by two different methods.

    PubMed

    Walter, R J; Matsuda, T; Reyes, H M; Walter, J M; Hanumadass, M

    1998-03-01

    The efficacy of acellular dermal matrix (ADM) in the treatment of full-thickness skin injuries as a dermal substitute depends on its low antigenicity, capacity for rapid vascularization, and stability as a dermal template. These properties will be determined largely by the final composition of the ADM. We have treated human skin with either Dispase followed by Triton X-100 detergent or NaCl followed by SDS detergent, cryosectioned the resulting ADMs, and then characterized them immunohistochemically. Staining for cell-associated antigens (HLA-ABC, HLA-DR, vimentin, desmin, talin), extracellular matrix components (chondroitin sulfate, fibronectin, laminin, vitronectin, hyaluronic acid), elastin, and collagen type VII was dramatically reduced or absent from ADMs prepared by both methods. However, significant amounts of elastin, keratan sulfate, laminin, and collagen types III and IV were still observed in both ADMs. Both methods of ADM preparation resulted in extensive extraction of both cellular and extracellular components of the skin but retention of the basic dermal architecture. In general, ADM prepared by the NaCl-SDS method retained larger amounts of each antigen than did that prepared by the Dispase-Triton method. This was most evident for laminin and type VII collagen but larger amounts of type IV collagen, fibronectin, desmin, elastin, and HLA-DR were also evident in the NaCl-SDS ADM.

  1. Phenotypic modulations of human umbilical vein endothelial cells and human dermal fibroblasts using two angiogenic assays.

    PubMed

    Bikfalvi, A; Cramer, E M; Tenza, D; Tobelem, G

    1991-01-01

    Different angiogenic assays in vitro have helped to define various events underlying angiogenesis. In this report we have compared the phenotypic modifications of human umbilical vein endothelial cells (HUVE cells) and human dermal fibroblasts using Matrigel and collagen gels. Both HUVE cells and human dermal fibroblasts form a network of anastomosing cords that apparently resemble blood capillaries when grown on Matrigel. The whole network was formed by several cellular aggregates joined to each other by cellular cords. Lumen formation was not observed in this angiogenic system. In opposite, considerable differences between HUVE cells and human dermal fibroblasts were observed in the three-dimensional angiogenic assay on collagen gels described by Montesano et al [14]. These results indicate that data obtained with angiogenic systems using Matrigel must be interpreted with caution and that the assay described by Montesano et al [14], is more reliable to describe angiogenesis.

  2. The role of collagen receptors Endo180 and DDR-2 in the foreign body reaction against non-crosslinked collagen and gelatin.

    PubMed

    Ye, Qingsong; Harmsen, Martin C; Ren, Yijin; Bank, Ruud A

    2011-02-01

    Despite the use of collagen-derived scaffolds in regenerative medicine, little is known about the degradation mechanisms of these scaffolds in vivo. Non-crosslinked dermal sheep (NDSC) and gelatin disks were implanted subcutaneously in mice. NDSC disks showed a very low degradation rate, despite the presence of high numbers of macrophages and the influx of neutrophils. This was attributed to the presence of the matrix metalloproteinase inhibitor TIMP-1. The limited degradation occurred mainly in the later stages of the foreign body reaction, and could be attributed to (1) phagocytosis by macrophages due to a co-expression of Endo180 and MT1-MMP on these cells (intracellular degradation) and (2) the presence of MMP-13 due to an upregulation of the expression of the DDR-2 receptor (extracellular degradation). In contrast, gelatin disks degraded quickly, due to the efficient formation of large giant cells as well as the presence of MMP-13; the inhibitor TIMP-1 was absent. The DDR-2 receptor was not expressed in the gelatin disks. Endo180 and MT1-MMP were expressed, but at most times no co-expression was seen. We conclude that the physical state of collagen (native or denatured) had a dramatic outcome on the degradation rate and provoked a completely different foreign body reaction.

  3. Evaluation of lymphangiogenesis in acellular dermal matrix

    PubMed Central

    Cherubino, Mario; Pellegatta, Igor; Tamborini, Federico; Cerati, Michele; Sessa, Fausto; Valdatta, Luigi

    2014-01-01

    Introduction: Much attention has been directed towards understanding the phenomena of angiogenesis and lymphangiogenesis in wound healing. Thanks to the manifold dermal substitute available nowadays, wound treatment has improved greatly. Many studies have been published about angiogenesis and cell invasion in INTEGRA®. On the other hand, the development of the lymphatic network in acellular dermal matrix (ADM) is a more obscure matter. In this article, we aim to characterize the different phases of host cell invasion in ADM. Special attention was given to lymphangiogenic aspects. Materials and Methods: Among 57 rats selected to analyse the role of ADM in lymphangiogenesis, we created four groups. We performed an excision procedure on both thighs of these rats: On the left one we did not perform any action except repairing the borders of the wound; while on the right one we used INTEGRA® implant. The excision biopsy was performed at four different times: First group after 7 days, second after 14 days, third after 21 days and fourth after 28 days. For our microscopic evaluation, we used the classical staining technique of haematoxylin and eosin and a semi-quantitative method in order to evaluate cellularity counts. To assess angiogenesis and lymphangiogenesis development we employed PROX-1 Ab and CD31/PECAM for immunohistochemical analysis. Results: We found remarkable wound contraction in defects that healed by secondary intention while minor wound contraction was observed in defects treated with ADM. At day 7, optical microscopy revealed a more plentiful cellularity in the granulation tissue compared with the dermal regeneration matrix. The immunohistochemical process highlighted vascular and lymphatic cells in both groups. After 14 days a high grade of fibrosis was noticeable in the non-treated group. At day 21, both lymphatic and vascular endothelial cells were better developed in the group with a dermal matrix application. At day 28, lymphatic endothelial

  4. EVALUATING COMMERCIALLY AVAILABLE DERMAL ...

    EPA Pesticide Factsheets

    As the Human Exposure Program focuses on the exposure of children to pesticides, there are concerns about the effect, or perceived effect, of components of the sampling procedure on the health and well-being of the infant and the ability to collect pesticide residues. One concern involves the materials in wipes used to collect pesticide residues or other contact materials on the skin. In recent studies (e.g., National Human Exposure Assessment Survey; NHEXAS), isopropyl alcohol has been used as a solvent in conjunction with a cloth wipe to obtain samples from the hands of adults and children. Although isopropyl alcohol is generally considered innocuous, the use of commercially available products could eliminate concerns about exposure to alcohol. A few studies have evaluated the potential of commercially available baby wipes to collect personal exposure samples for metals research, but not for the area of pesticide research (Millson et al., 1994; Campbell et al., 1993; Lichtenwalner et al., 1993). Therefore, there is a need to evaluate the potential for using commercially available baby wipes for collecting pesticide samples from skin and other surfaces. Another concern involves establishing a convenient and safe method for assessing overall dermal exposure for children, especially for those in crawling stage. One route that the U .S. Environmental Protection Agency (EPA) would like to investigate is the use of cotton body suits (infant sleepers) as an indicator

  5. Human acellular dermal matrix allograft: A randomized, controlled human trial for the long-term evaluation of patients with extensive burns.

    PubMed

    Li, Xueyong; Meng, Xianghai; Wang, Xiaolin; Li, Yuejun; Li, Wangzhou; Lv, Xiaoxing; Xu, Xiaoli; Lei, Zhanjun; Li, Jinqing

    2015-06-01

    The potential of acellular dermal matrix (ADM) to improve cosmetic and functional outcomes has been demonstrated; however, there have been few clinical comparative studies assessing the long-term morphological, histological and functional changes after ADM placement. This study was designed to retrospectively evaluate the long-term outcomes of the cograft acellular dermal matrix with autologous thin split-thickness skin for the coverage of wounds in extensively burned patients. Thirty burn patients treated with a composite graft of ADM with autologous split-thickness skin from January 2007 to December 2009 were enrolled in this study. Another group of thirty patients who received only an autogenous split-thickness skin implant served as the control. Our study revealed that the collagen in the dermis treated with ADM were ordered, and the proportion of collagen III/I was much higher in the control group than in the ADM group. The basement membrane was prominent and continuous. Meanwhile, the VBSS (Vancouver Burn Skin Score) was used to evaluate skin quality, which shows a significant differences between the two group (P<0.001). Then the functional level was evaluated by the BI (Barthel Index), and the ADM group was much better than the control group (P=0.005). Based on these results, we concluded that the composite graft of ADM with autologous thin split-thickness skin was suitable for repairing the defects in functional areas after a burn. This technique might facilitate wound management with acceptable esthetic outcomes, good functional recovery and less scar hyperplasia at the donor site.

  6. Biofunctionalization of silicone rubber with microgroove-patterned surface and carbon-ion implantation to enhance biocompatibility and reduce capsule formation

    PubMed Central

    Lei, Ze-yuan; Liu, Ting; Li, Wei-juan; Shi, Xiao-hua; Fan, Dong-li

    2016-01-01

    Purpose Silicone rubber implants have been widely used to repair soft tissue defects and deformities. However, poor biocompatibility can elicit capsule formation, usually resulting in prosthesis contracture and displacement in long-term usage. To overcome this problem, this study investigated the properties of silicone rubber materials with or without a microgroove-patterned surface and with or without carbon (C)-ion implantation. Materials and methods Atomic force microscopy, X-ray photoelectron spectroscopy, and a water contact angle test were used to characterize surface morphology and physicochemical properties. Cytocompatibility was investigated by a cell adhesion experiment, immunofluorescence staining, a Cell Counting Kit-8 assay, and scanning electron microscopy in vitro. Histocompatibility was evaluated by studying the inflammatory response and fiber capsule formation that developed after subcutaneous implantation in rats for 7 days, 15 days, and 30 days in vivo. Results Parallel microgrooves were found on the surfaces of patterned silicone rubber (P-SR) and patterned C-ion-implanted silicone rubber (PC-SR). Irregular larger peaks and deeper valleys were present on the surface of silicone rubber implanted with C ions (C-SR). The silicone rubber surfaces with microgroove patterns had stable physical and chemical properties and exhibited moderate hydrophobicity. PC-SR exhibited moderately increased dermal fibroblast cell adhesion and growth, and its surface microstructure promoted orderly cell growth. Histocompatibility experiments on animals showed that both the anti-inflammatory and antifibrosis properties of PC-SR were slightly better than those of the other materials, and there was also a lower capsular contracture rate and less collagen deposition around implants made from PC-SR. Conclusion Although the surface chemical properties, dermal fibroblast cell growth, and cell adhesion were not changed by microgroove pattern modification, a more orderly cell

  7. Collagenous colitis.

    PubMed Central

    Kingham, J G; Levison, D A; Morson, B C; Dawson, A M

    1986-01-01

    Clinical and pathological aspects of six patients with collagenous colitis are presented. These patients have been observed for between four and 15 years and the evolution of the condition is documented in three (cases 1, 3 and 5). Management and possible pathogenetic mechanisms of this enigmatic condition are discussed. Images Fig. 1 Fig. 2 PMID:3699567

  8. Collagenous gastritis.

    PubMed

    Jin, Xiaoyi; Koike, Tomoyuki; Chiba, Takashi; Kondo, Yutaka; Ara, Nobuyuki; Uno, Kaname; Asano, Naoki; Iijima, Katsunori; Imatani, Akira; Watanabe, Mika; Shirane, Akio; Shimosegawa, Tooru

    2013-09-01

    In the present paper, we report a case of rare collagenous gastritis. The patient was a 25-year-old man who had experienced nausea, abdominal distention and epigastralgia since 2005. Esophagogastroduodenoscopy (EGD) carried out at initial examination by the patient's local doctor revealed an extensively discolored depression from the upper gastric body to the lower gastric body, mainly including the greater curvature, accompanied by residual mucosa with multiple islands and nodularity with a cobblestone appearance. Initial biopsies sampled from the nodules and accompanying atrophic mucosa were diagnosed as chronic gastritis. In August, 2011, the patient was referred to Tohoku University Hospital for observation and treatment. EGD at our hospital showed the same findings as those by the patient's local doctor. Pathological findings included a membranous collagen band in the superficial layer area of the gastric mucosa, which led to a diagnosis of collagenous gastritis. Collagenous gastritis is an extremely rare disease, but it is important to recognize its characteristic endoscopic findings to make a diagnosis.

  9. Improved epidermal barrier formation in human skin models by chitosan modulated dermal matrices

    PubMed Central

    Mieremet, Arnout; Rietveld, Marion; Absalah, Samira; van Smeden, Jeroen

    2017-01-01

    Full thickness human skin models (FTMs) contain an epidermal and a dermal equivalent. The latter is composed of a collagen dermal matrix which harbours fibroblasts. Current epidermal barrier properties of FTMs do not fully resemble that of native human skin (NHS), which makes these human skin models less suitable for barrier related studies. To further enhance the resemblance of NHS for epidermal morphogenesis and barrier formation, we modulated the collagen dermal matrix with the biocompatible polymer chitosan. Herein, we report that these collagen-chitosan FTMs (CC-FTMs) possess a well-organized epidermis and maintain both the early and late differentiation programs as in FTMs. Distinctively, the epidermal cell activation is reduced in CC-FTMs to levels observed in NHS. Dermal-epidermal interactions are functional in both FTM types, based on the formation of the basement membrane. Evaluation of the barrier structure by the organization of the extracellular lipid matrix of the stratum corneum revealed an elongated repeat distance of the long periodicity phase. The ceramide composition exhibited a higher resemblance of the NHS, based on the carbon chain-length distribution and subclass profile. The inside-out barrier functionality indicated by the transepidermal water loss is significantly improved in the CC-FTMs. The expression of epidermal barrier lipid processing enzymes is marginally affected, although more restricted to a single granular layer. The novel CC-FTM resembles the NHS more closely, which makes them a promising tool for epidermal barrier related studies. PMID:28333992

  10. VEGF released by deferoxamine preconditioned mesenchymal stem cells seeded on collagen-GAG substrates enhances neovascularization

    PubMed Central

    Wahl, Elizabeth A.; Schenck, Thilo L.; Machens, Hans-Günther; Balmayor, Elizabeth R.

    2016-01-01

    Hypoxia preconditioning of mesenchymal stem cells (MSCs) has been shown to promote wound healing through HIF-1α stabilization. Preconditioned MSCs can be applied to three-dimensional biomaterials to further enhance the regenerative properties. While environmentally induced hypoxia has proven difficult in clinical settings, this study compares the wound healing capabilities of adipose derived (Ad) MSCs seeded on a collagen-glycosaminoglycan (GAG) dermal substrate exposed to either environmental hypoxia or FDA approved deferoxamine mesylate (DFO) to stabilize HIF-1α for wound healing. The release of hypoxia related reparative factors by the cells on the collagen-GAG substrate was evaluated to detect if DFO produces results comparable to environmentally induced hypoxia to facilitate optimal clinical settings. VEGF release increased in samples exposed to DFO. While the SDF-1α release was lower in cells exposed to environmental hypoxia in comparison to cells cultured in DFO in vitro. The AdMSC seeded biomaterial was further evaluated in a murine model. The implants where harvested after 1 days for histological, inflammatory, and protein analysis. The application of DFO to the cells could mimic and enhance the wound healing capabilities of environmentally induced hypoxia through VEGF expression and promises a more viable option in clinical settings that is not merely restricted to the laboratory. PMID:27830734

  11. Accelerated wound healing in a diabetic rat model using decellularized dermal matrix and human umbilical cord perivascular cells.

    PubMed

    Milan, P Brouki; Lotfibakhshaiesh, N; Joghataie, M T; Ai, J; Pazouki, A; Kaplan, D L; Kargozar, S; Amini, N; Hamblin, M R; Mozafari, M; Samadikuchaksaraei, A

    2016-11-01

    There is an unmet clinical need for novel wound healing strategies to treat full thickness skin defects, especially in diabetic patients. We hypothesized that a scaffold could perform dual roles of a biomechanical support and a favorable biochemical environment for stem cells. Human umbilical cord perivascular cells (HUCPVCs) have been recently reported as a type of mesenchymal stem cell that can accelerate early wound healing in skin defects. However, there are only a limited number of studies that have incorporated these cells into natural scaffolds for dermal tissue engineering. The aim of the present study was to promote angiogenesis and accelerate wound healing by using HUCPVCs and decellularized dermal matrix (DDM) in a rat model of diabetic wounds. The DDM scaffolds were prepared from harvested human skin samples and histological, ultrastructural, molecular and mechanical assessments were carried out. In comparison with the control (without any treatment) and DDM alone group, full thickness excisional wounds treated with HUCPVCs-loaded DDM scaffolds demonstrated an accelerated wound closure rate, faster re-epithelization, more granulation tissue formation and decreased collagen deposition. Furthermore, immunofluorescence analysis showed that the VEGFR-2 expression and vascular density in the HUCPVCs-loaded DDM scaffold treated group were also significantly higher than the other groups at 7days post implantation. Since the rates of angiogenesis, re-epithelization and formation of granulation tissue are directly correlated with full thickness wound healing in patients, the proposed HUCPVCs-loaded DDM scaffolds may fulfil a role neglected by current treatment strategies. This pre-clinical proof-of-concept study warrants further clinical evaluation.

  12. Acceleration of bone formation during fracture healing by injectable collagen powder and human basic fibroblast growth factor containing a collagen-binding domain from Clostridium histolyticum collagenase.

    PubMed

    Saito, Wataru; Uchida, Kentaro; Ueno, Masaki; Matsushita, Osamu; Inoue, Gen; Nishi, Nozomu; Ogura, Takayuki; Hattori, Shunji; Fujimaki, Hisako; Tanaka, Keisuke; Takaso, Masashi

    2014-09-01

    Growth factor delivered with implantable biomaterials has been used to both accelerate and ensure healing of open fractures in human patients. However, a major limitation of implantable biomaterials is the requirement for open surgical placement. Here, we developed an injectable collagen material-based bone formation system consisting of injectable collagen powder with fibril morphology and collagen triple helix conformation, and basic fibroblast growth factor (bFGF) fused to the collagen-binding domain (CBD) of Clostridium histolyticum collagenase. The affinity of the CBD towards collagen was confirmed by the results of collagen-binding assays. Moreover, the combination of the collagen binding-bFGF fusion protein (CB-bFGF) with injectable collagen powder induced bone formation at protein concentrations lower than those required for bFGF alone in mice fracture models. Taken together, these properties suggest that the CB-bFGF/collagen powder composite is a promising injectable material for bone repair in the clinical setting.

  13. Extracellular Matrix and Dermal Fibroblast Function in the Healing Wound

    PubMed Central

    Tracy, Lauren E.; Minasian, Raquel A.; Caterson, E.J.

    2016-01-01

    Significance: Fibroblasts play a critical role in normal wound healing. Various extracellular matrix (ECM) components, including collagens, fibrin, fibronectin, proteoglycans, glycosaminoglycans, and matricellular proteins, can be considered potent protagonists of fibroblast survival, migration, and metabolism. Recent Advances: Advances in tissue culture, tissue engineering, and ex vivo models have made the examination and precise measurements of ECM components in wound healing possible. Likewise, the development of specific transgenic animal models has created the opportunity to characterize the role of various ECM molecules in healing wounds. In addition, the recent characterization of new ECM molecules, including matricellular proteins, dermatopontin, and FACIT collagens (Fibril-Associated Collagens with Interrupted Triple helices), further demonstrates our cursory knowledge of the ECM in coordinated wound healing. Critical Issues: The manipulation and augmentation of ECM components in the healing wound is emerging in patient care, as demonstrated by the use of acellular dermal matrices, tissue scaffolds, and wound dressings or topical products bearing ECM proteins such as collagen, hyaluronan (HA), or elastin. Once thought of as neutral structural proteins, these molecules are now known to directly influence many aspects of cellular wound healing. Future Directions: The role that ECM molecules, such as CCN2, osteopontin, and secreted protein, acidic and rich in cysteine, play in signaling homing of fibroblast progenitor cells to sites of injury invites future research as we continue investigating the heterotopic origin of certain populations of fibroblasts in a healing wound. Likewise, research into differently sized fragments of the same polymeric ECM molecule is warranted as we learn that fragments of molecules such as HA and tenascin-C can have opposing effects on dermal fibroblasts. PMID:26989578

  14. Clinical Performance of a Dermal Filler Containing Natural Glycolic Acid and a Polylactic Acid Polymer

    PubMed Central

    Macchetto, Pedro Cervantes; Durán Páramo, Rosa Margarita

    2010-01-01

    Lipoatrophy is a condition that affects certain individuals, most commonly those who are infected with the human immunodeficiency virus.1–3 Injectable fillers are used for the treatment of these dermal contour deformities to smooth dermal depressions formed by the loss of volume. These dermal fillers (also known as soft tissue augmentation devices) can correct contour deformities caused by lipoatrophy in patients who are human immunodeficiency virus positive or negative. The product used in this study is a patented, second-generation, injectable, dermal collagen stimulator that combines glycolic acid and polylactic acid. The glycolic acid used is not a polymer, but rather an acid derived from sugar cane. Its chemical structure corresponds to that of an alpha-hydroxy acid. Glycolic acid is a well-characterized agent that is present in a number of cosmetic products. Polylactic acid is a synthetic, biocompatible, biodegradable, inert, synthetic polymer from the poly a-hydroxy-acid family that is believed to stimulate fibroblasts to produce more collagen, thus increasing facial volume. Together, polylactic acid and glycolic acid act in concert to 1) stimulate collagen production and 2) hydrate the outer layers of the skin. A multicenter, clinical investigation authorized by the Mexican Secretariat of Health was conducted between September 20, 2002, and September 19, 2004. This clinical study was conducted in male patients between 32 and 60 years of age with lipoatrophy as a result of highly active antiretroviral therapy for human immunodeficiency virus infection. The study objective was to measure the improvement of contour deformities after the injection of a dermal collagen stimulator containing glycolic acid and polylactic acid. In addition to safety, this dermal filler was assessed when used to correct volume deformities caused by lipoatrophy in subjects who are human immunodeficiency virus positive. Thirty male subjects participated and were treated as follows

  15. FIZZ1-induced myofibroblast transdifferentiation from adipocytes and its potential role in dermal fibrosis and lipoatrophy.

    PubMed

    Martins, Vanessa; Gonzalez De Los Santos, Francina; Wu, Zhe; Capelozzi, Vera; Phan, Sem H; Liu, Tianju

    2015-10-01

    Subcutaneous lipoatrophy characteristically accompanies dermal fibrosis with de novo emergence of myofibroblasts such as in systemic sclerosis or scleroderma. Recently dermal adipocytes were shown to have the capacity to differentiate to myofibroblasts in an animal model. Transforming growth factor β can induce this phenomenon in vitro; however its in vivo significance is unclear. Because found in inflammatory zone 1 (FIZZ1) is an inducer of myofibroblast differentiation but an inhibitor of adipocyte differentiation, we investigated its potential role in adipocyte transdifferentiation to myofibroblast in dermal fibrosis. FIZZ1 caused significant and rapid suppression of the expression of fatty acid binding protein 4 and peroxisome proliferator-activated receptor-γ in adipocytes, consistent with dedifferentiation with loss of lipid and Oil Red O staining. The suppression was accompanied subsequently with stimulation of α-smooth muscle actin and type I collagen expression, indicative of myofibroblast differentiation. In vivo FIZZ1 expression was significantly elevated in the murine bleomycin-induced dermal fibrosis model, which was associated with significant reduction in adipocyte marker gene expression and subcutaneous lipoatrophy. Finally, FIZZ1 knockout mice exhibited significantly reduced bleomycin-induced dermal fibrosis with greater preservation of the subcutaneous fat than wild-type mice. These findings suggested that the FIZZ1 induction of adipocyte transdifferentiation to myofibroblast might be a key pathogenic mechanism for the accumulation of myofibroblasts in dermal fibrosis.

  16. Fabrication of duck's feet collagen-silk hybrid biomaterial for tissue engineering.

    PubMed

    Kim, Soo Hyeon; Park, Hae Sang; Lee, Ok Joo; Chao, Janet Ren; Park, Hyun Jung; Lee, Jung Min; Ju, Hyung Woo; Moon, Bo Mi; Park, Ye Ri; Song, Jeong Eun; Khang, Gilson; Park, Chan Hum

    2016-04-01

    Collagen constituting the extracellular matrix has been widely used as biocompatible material for human use. In this study, we have selected duck's feet for extracting collagen. A simple method not utilizing harsh chemical had been employed to extract collagen from duck's feet. We fabricated duck's feet collagen/silk hybrid scaffold for the purpose of modifying the degradation rate of duck's feet collagen. This study suggests that extracted collagen from duck's feet is biocompatible and resembles collagen extracted from porcine which is commercially used. Duck's feet collagen is also economically feasible and it could therefore be a good candidate as a tissue engineering material. Further, addition of silk to fabricate a duck's feet collagen/silk hybrid scaffold could enhance the biostability of duck's feet collagen scaffold. Duck's feet collagen/silk scaffold increased the cell viability compared to silk alone. Animal studies also showed that duck's feet collagen/silk scaffold was more biocompatible than silk alone and more biostable than duck's feet or porcine collagen alone. Additionally, the results revealed that duck's feet collagen/silk hybrid scaffold had high porosity, cell infiltration and proliferation. We suggest that duck's feet collagen/silk hybrid scaffold could be used as a dermal substitution for full thickness skin defects.

  17. Collagen XVII: A Shared Antigen in Neurodermatological Interactions?

    PubMed Central

    2013-01-01

    Collagen XVII is a nonfibril-forming transmembrane collagen, which functions as both a matrix protein and a cell-surface receptor. It is particularly copious in the skin, where it is known to be a structural component of hemidesmosomes. In addition, collagen XVII has been found to be present in the central nervous system, thus offering an explanation for the statistical association between bullous pemphigoid, in which autoimmunity is directed against dermal collagen XVII, and neurological diseases. In support of the hypothesis that collagen XVII serves as a shared antigen mediating an immune response between skin and brain, research on animal and human tissue, as well as numerous epidemiological and case studies, is presented. PMID:23878581

  18. Efficient In Vitro Electropermeabilization of Reconstructed Human Dermal Tissue.

    PubMed

    Madi, Moinecha; Rols, Marie-Pierre; Gibot, Laure

    2015-10-01

    DNA electrotransfer is a successful technic for gene delivery. However, its use in clinical applications is limited since little is known about the mechanisms governing DNA electrotransfer in the complex environment occurring in a tissue. The objectives of this work were to investigate the role of the extracellular matrix (ECM) in that process. Tumor ECM composition was shown to modulate in vivo gene electrotransfer efficiency. In order to assess the effects of ECM composition and organization, as well as intercellular junctions and communication, in normal tissue response to electric pulses, we developed an innovative three-dimensional (3D) reconstructed human connective tissue model. 3D human dermal tissue was reconstructed in vitro by a tissue engineering approach and was representative of in vivo cell organization since cell-cell contacts were present as well as complex ECM. This human cell model presented multiple layers of primary dermal fibroblasts embedded in a native, collagen-rich ECM. This dermal tissue could become a useful tool to study skin DNA electrotransfer mechanisms. As proof of the concept, we show here that the cells within this standardized 3D tissue can be efficiently electropermeabilized by milliseconds electric pulses. We believe that a better comprehension of gene electrotransfer in such a model tissue would help improve electrogene therapy approaches such as the systemic delivery of therapeutic proteins and DNA vaccination.

  19. In vivo biological responses and bioresorption of tilapia scale collagen as a potential biomaterial.

    PubMed

    Sugiura, Hiroaki; Yunoki, Shunji; Kondo, Eiji; Ikoma, Toshiyuki; Tanaka, Junzo; Yasuda, Kazunori

    2009-01-01

    To date, collagen for biomedical uses has been obtained from mammalian sources. The purpose of this study was to evaluate the in vivo biological responses and bioresorption of collagen obtained from tilapia (Oreochromis niloticas) scales as compared to those of collagen from porcine dermis. Collagen sponges with micro-porous structures were fabricated from reconstituted collagen fibrils using freeze-drying and cross-linked by dehydrothermal treatment (DHT treatment) or additional treatment with a water-soluble carbodiimide (WSC treatment). The mechanical properties of the tilapia collagen sponges were similar to those of porcine collagen sponges with the same cross-linking methods, where WSC treatment remarkably improved the properties over DHT treatment alone. The pellet implantation tests into the paravertebral muscle of rabbits demonstrated that tilapia collagen caused rare inflammatory responses at 1- and 4-week implantations, statistically similar to those of porcine collagen and a high-density polyethylene as a negative control. The bioresorption rates of both the collagen implants were similar, except for the DHT-treated tilapia collagen sponges at 1-week implantation. These results suggest that tilapia collagen is a potential alternative to conventional mammalian collagens in biomedical uses.

  20. Antioxidant effects of the sarsaparilla via scavenging of reactive oxygen species and induction of antioxidant enzymes in human dermal fibroblasts.

    PubMed

    Park, Gunhyuk; Kim, Tae-mi; Kim, Jeong Hee; Oh, Myung Sook

    2014-07-01

    Ultraviolet (UV) radiation from sunlight causes distinct changes in collagenous skin tissues as a result of the breakdown of collagen, a major component of the extracellular matrix. UV irradiation downregulates reactive oxygen species (ROS)-elimination pathways, thereby promoting the production of ROS, which are implicated in skin aging. Smilax glabra Roxb (sarsaparilla) has been used in folk medicine because of its many effects. However, no study on the protective effects of sarsaparilla root (SR) on human dermal fibroblasts has been reported previously. Here, we investigated the protective effect of SR against oxidative stress in dermal fibroblasts. SR significantly inhibited oxidative damage and skin-aging factor via mitogen-activated protein kinase signaling pathways. Also, SR decreased Ca(2+) and ROS, mitochondrial membrane potential, dysfunction, and increased glutathione, NAD(P)H dehydrogenase and heme oxygenase-1. These results demonstrate that SR can protect dermal fibroblasts against UVB-induced skin aging via antioxidant effects.

  1. UV-Induced Triggering of a Biomechanical Initiation Switch within Collagen Promotes Development of a Melanoma-Permissive Microenvironment in the Skin

    DTIC Science & Technology

    2013-09-01

    MatrigelTM has on inflammatory cell, dermal fibroblast, and melanoma cell adhesion, migration, invasion and proliferation as compared to control ECM...indicated that UVA and UVB irradiation can dose dependently induce conformational changes in both collagen type-I and collagen type-IV resulting in the...expressed αSMA, a known marker of an activated phenotype. As shown in figure 1A the in vitro cultured human dermal fibroblast used in our studies

  2. Dermal uptake of petroleum substances.

    PubMed

    Jakasa, Ivone; Kezic, Sanja; Boogaard, Peter J

    2015-06-01

    Petroleum products are complex substances comprising varying amounts of linear and branched alkanes, alkenes, cycloalkanes, and aromatics which may penetrate the skin at different rates. For proper interpretation of toxic hazard data, understanding their percutaneous absorption is of paramount importance. The extent and significance of dermal absorption of eight petroleum substances, representing different classes of hydrocarbons, was evaluated. Literature data on the steady-state flux and permeability coefficient of these substances were evaluated and compared to those predicted by mathematical models. Reported results spanned over 5-6 orders of magnitude and were largely dependent on experimental conditions in particular on the type of the vehicle used. In general, aromatic hydrocarbons showed higher dermal absorption than more lipophilic aliphatics with similar molecular weight. The results showed high variation and were largely influenced by experimental conditions emphasizing the need of performing the experiments under "in use" scenario. The predictive models overestimated experimental absorption. The overall conclusion is that, based on the observed percutaneous penetration data, dermal exposure to petroleum hydrocarbons, even of aromatics with highest dermal absorption is limited and highly unlikely to be associated with health risks under real use scenarios.

  3. Collagen degradation in rat skin but not in intestine during rapid growth: effect on collagen types I and III from skin.

    PubMed Central

    Klein, L; ChandraRajan, J

    1977-01-01

    Metabolic degradation of prelabeled collagen in whole body skin and whole intestine was compared to that of types I and III collagens from skin in young, rapidly growing rats. Pregnant rats were given [3H]proline during the last week of gestation; and after birth, littermates were compared. Between the second and sixth weeks of age, there was a 43% loss of radioactivity from dermal collagen but no significant loss of radioactivity from intestinal collagen. Pepsin treatment solubilized 90% of the dermal collagen but only 12% of intestinal collagen. Skin from 2- and 6-week-old rats yielded the same proportions of type I and type III collagens (type I, 82%; type III, 18%). The relative losses of total radioactivity from types I and III were similar to each other (50 and 44%, respectively) and to the loss from whole skin. Because types I and III collagens are known to be present in both skin and intestine, the marked degradation of both collagen types in skin but not in the intestine may be related to the amount and kind of intermolecular crosslinks present. PMID:266184

  4. Tenascin-x deficiency mimics ehlers-danlos syndrome in mice through alteration of collagen deposition

    SciTech Connect

    Mao, J.R.; Taylor, G.; Dean, W.B.; Wagner, D.R.; Afzal, V.; Lotz, J.C.; Rubin, E.M.; Bristow, J.

    2002-03-01

    Tenascin-X is a large extracellular matrix protein of unknown function1-3. Tenascin-X deficiency in humans is associated with Ehlers-Danlos syndrome4,5, a generalized connective tissue disorder resulting from altered metabolism of the fibrillar collagens6. Because TNXB is the first Ehlers-Danlos syndrome gene that does not encode a fibrillar collagen or collagen-modifying enzyme7-14, we suggested that tenascin-X might regulate collagen synthesis or deposition15. To test this hypothesis, we inactivated Tnxb in mice. Tnxb-/- mice showed progressive skin hyperextensibility, similar to individuals with Ehlers-Danlos syndrome. Biomechanical testing confirmed increased deformability and reduced tensile strength of their skin. The skin of Tnxb-/- mice was histologically normal, but its collagen content was significantly reduced. At the ultrastructural level, collagen fibrils of Tnxb-/- mice were of normal size and shape, but the density of fibrils in their skin was reduced, commensurate with the reduction in collagen content. Studies of cultured dermal fibroblasts showed that although synthesis of collagen I by Tnxb-/- and wildtype cells was similar, Tnxb-/- fibroblasts failed to deposit collagen I into cell-associated matrix. This study confirms a causative role for TNXB in human Ehlers-Danlos syndrome and suggests that tenascin-X is an essential regulator of collagen deposition by dermal fibroblasts.

  5. Treatment of photoaged skin with topical tretinoin increases epidermal-dermal anchoring fibrils

    SciTech Connect

    Woodley, D.T.; Briggaman, R.A. ); Zelickson, A.S. ); Hamilton, T.A.; Weiss, J.S.; Ellis, C.N.; Voorhees, J.J. )

    1990-06-13

    Topical 0.1% tretinoin or vehicle control was applied daily to the forearm skin of six caucasian adults for 4 months. Two-millimeter punch biopsy specimens were obtained from treatment sites at the beginning and end of the study period for electron microscopy. Anchoring fibrils within the epidermal-dermal junction of skin treatment sites were quantitated by blinded, standardized, computer-assisted morphometry. After 4 months of continual daily treatment, skin sites that received topical tretinoin showed double the anchoring fibril density compared with vehicle control sites. The possible mechanism by which topical tretinoin increases anchoring fibrils in skin include the drug's property of inhibiting collagenase, a dermal enzyme that degrades anchoring fibril collagen. The authors speculate that increased numbers of collagenous anchoring fibrils within the papillary dermis of human skin is one of the connective-tissue correlates of the clinical improvement observed in photoaged skin after treatment with topical tretinoin.

  6. Chronic UVB-irradiation actuates perpetuated dermal matrix remodeling in female mice: Protective role of estrogen

    PubMed Central

    Röck, Katharina; Joosse, Simon Andreas; Müller, Julia; Heinisch, Nina; Fuchs, Nicola; Meusch, Michael; Zipper, Petra; Reifenberger, Julia; Pantel, Klaus; Fischer, Jens Walter

    2016-01-01

    Chronic UVB-exposure and declined estradiol production after menopause represent important factors leading to extrinsic and intrinsic aging, respectively. Remodeling of the extracellular matrix (ECM) plays a crucial role in both responses. Whether the dermal ECM is able to recover after cessation of UVB-irradiation in dependence of estradiol is not known, however of relevance when regarding possible treatment options. Therefore, the endogenous sex hormone production was depleted by ovariectomy in female mice. Half of the mice received estradiol substitution. Mice were UVB-irradiated for 20 weeks and afterwards kept for 10 weeks without irradiation. The collagen-, hyaluronan- and proteoglycan- (versican, biglycan, lumican) matrix, collagen cleavage products and functional skin parameters were analyzed. The intrinsic aging process was characterized by increased collagen fragmentation and accumulation of biglycan. Chronic UVB-irradiation additionally augmented the lumican, versican and hyaluronan content of the dermis. In the absence of further UVB-irradiation the degradation of collagen and accumulation of biglycan in the extrinsically aged group was perpetuated in an excessive matter. Whereas estradiol increased the proteoglycan content, it reversed the effects of the perpetuated extrinsic response on collagen degradation. Suspension of the intrinsic pathway might therefore be sufficient to antagonize UVB-evoked long-term damage to the dermal ECM. PMID:27460287

  7. Effect of photon energy in collagen generation by interstitial low level laser stimulation

    NASA Astrophysics Data System (ADS)

    Jun, Eunkwon; Ha, Myungjin; Lee, Sangyeob; Radfar, Edalat; Park, Jihoon; Jung, Byungjo

    2015-03-01

    Although the mechanism of low level laser therapy (LLLT) is unclear, many studies demonstrated the positive clinical performance of LLLT for skin rejuvenation. An increase in dermal collagen plays an important role in skin rejuvenation and wound healing. This study aimed to investigate collagen generation after interstitial low level laser stimulation (ILLS). Rabbits were divided into two groups: surfacing irradiation and minimally invasive irradiation. 660nm diode laser of 20mW with 10J, 13J and 15J was applied to the backside of rabbits. Collagen formation was evaluated with ultrasound skin scanner every 12 hours. Results shows that ILLS groups have denser collagen density than surfacing groups.

  8. Real-time in vivo imaging collagen in lymphedematous skin using multiphoton microscopy.

    PubMed

    Wu, Xiufeng; Zhuo, Shuangmu; Chen, Jianxin; Liu, Ningfei

    2011-01-01

    Changes of dermal collagen are characteristic for chronic lymphedema. To evaluate these changes, a real-time imaging based on two-photon excited fluorescence and second-harmonic generation was developed for investigating collagen of lymphedematous mouse and rat tail skin in vivo. Our findings showed that the technique could image the morphological changes and distribution of collagen in lymphedematous mouse and rat tail skin in vivo. More importantly, it may allow visualization of dynamic collagen alteration during the progression of lymphedema. Our findings demonstrated that multiphoton microscopy may have potential in a clinical setting as an in vivo diagnostic and monitoring system for therapy in lymphology.

  9. A Hydrogel Derived From Decellularized Dermal Extracellular Matrix

    PubMed Central

    Wolf, Matthew T.; Daly, Kerry A.; Brennan-Pierce, Ellen P.; Johnson, Scott A.; Carruthers, Christopher; D’Amore, Antonio; Nagarkar, Shailesh P.; Velankar, Sachin S.; Badylak, Stephen F.

    2012-01-01

    The ECM of mammalian tissues has been used as a scaffold to facilitate the repair and reconstruction of numerous tissues. Such scaffolds are prepared in many forms including sheets, powders, and hydrogels. ECM hydrogels provide advantages such as injectability, the ability to fill an irregularly shaped space, and the inherent bioactivity of native matrix. However, material properties of ECM hydrogels and the effect of these properties upon cell behavior are neither well understood nor controlled. The objective of this study was to prepare and determine the structure, mechanics, and the cell response in vitro and in vivo of ECM hydrogels prepared from decellularized porcine dermis and urinary bladder tissues. Dermal ECM hydrogels were characterized by a more dense fiber architecture and greater mechanical integrity than urinary bladder ECM hydrogels, and showed a dose dependent increase in mechanical properties with ECM concentration. In vitro, dermal ECM hydrogels supported greater C2C12 myoblast fusion, and less fibroblast infiltration and less fibroblast mediated hydrogel contraction than urinary bladder ECM hydrogels. Both hydrogels were rapidly infiltrated by host cells, primarily macrophages, when implanted in a rat abdominal wall defect. Both ECM hydrogels degraded by 35 days in vivo, but UBM hydrogels degraded more quickly, and with greater amounts of myogenesis than dermal ECM. These results show that ECM hydrogel properties can be varied and partially controlled by the scaffold tissue source, and that these properties can markedly affect cell behavior. PMID:22789723

  10. Quantitative analysis of intrinsic skin aging in dermal papillae by in vivo harmonic generation microscopy

    PubMed Central

    Liao, Yi-Hua; Kuo, Wei-Cheng; Chou, Sin-Yo; Tsai, Cheng-Shiun; Lin, Guan-Liang; Tsai, Ming-Rung; Shih, Yuan-Ta; Lee, Gwo-Giun; Sun, Chi-Kuang

    2014-01-01

    Chronological skin aging is associated with flattening of the dermal-epidermal junction (DEJ), but to date no quantitative analysis focusing on the aging changes in the dermal papillae (DP) has been performed. The aim of the study is to determine the architectural changes and the collagen density related to chronological aging in the dermal papilla zone (DPZ) by in vivo harmonic generation microscopy (HGM) with a sub-femtoliter spatial resolution. We recruited 48 Asian subjects and obtained in vivo images on the sun-protected volar forearm. Six parameters were defined to quantify 3D morphological changes of the DPZ, which we analyzed both manually and computationally to study their correlation with age. The depth of DPZ, the average height of isolated DP, and the 3D interdigitation index decreased with age, while DP number density, DP volume, and the collagen density in DP remained constant over time. In vivo high-resolution HGM technology has uncovered chronological aging-related variations in DP, and sheds light on real-time quantitative skin fragility assessment and disease diagnostics based on collagen density and morphology. PMID:25401037

  11. Possible association of elevated serum collagen type IV level with skin sclerosis in systemic sclerosis.

    PubMed

    Motegi, Sei-Ichiro; Sekiguchi, Akiko; Fujiwara, Chisako; Toki, Sayaka; Ishikawa, Osamu

    2016-08-29

    Collagen type IV is the primary collagen in the basement membranes around blood vessels and in the dermoepidermal junction in the skin. Perivascular collagen type IV is synthesized by endothelial cells and pericytes, and contributes to the homeostasis and remodeling of blood vessels. It has been well recognized that elevated serum collagen type IV levels are associated with the liver fibrosis. The objective was to examine serum collagen type IV levels and their clinical associations in patients with systemic sclerosis (SSc), and to examine the expression of collagen type IV in the fibrotic skin in SSc. Serum collagen type IV levels in SSc patients and diffuse cutaneous type SSc patients were significantly higher than those in healthy individuals. Serum collagen type IV levels were positively correlated with modified Rodnan total skin score. Serum collagen type IV levels in early stage (disease duration ≤3 years) diffuse cutaneous SSc patients were significantly elevated. Serum collagen type IV levels in SSc patients with digital ulcers (DU) were significantly elevated. In immunohistochemical staining, the expression of collagen type IV around dermal small vessels in the affected skin was reduced compared with those of normal individuals. These results suggest that elevated serum collagen type IV levels may be associated with the skin sclerosis in the early stage of SSc. The measurement of serum collagen type IV levels in SSc patients may be useful as a disease activity marker in skin sclerosis and DU.

  12. Prediction & Assessment of Dermal Exposure

    DTIC Science & Technology

    2007-11-02

    cutaneous exposure requires the transdermal penetration of the chemical. The unique permeation barrier properties of skin ensure that the kinetics of...following dermal exposure, therefore, requires that the rate of skin penetration in man be predictable. The specific aims of the project were: (1) to...derive, from a compre- hensive database of the percutaneous absorption/ penetration literature predictive ("structure-activity") algorithms to calculate a

  13. The effect of thrombocytopenia on dermal wound healing.

    PubMed

    Szpaderska, Anna M; Egozi, Eric I; Gamelli, Richard L; DiPietro, Luisa A

    2003-06-01

    The immediate appearance of platelets in wounds and the ability of platelets to release growth factors suggest that platelets are an important trigger of the tissue repair process. To examine the effect of systemic thrombocytopenia on both the inflammatory and proliferative aspects of wound healing, adult mice were rendered thrombocytopenic by intraperitoneal administration of a rabbit antimouse platelet serum. Full-thickness excisional dermal wounds were prepared and analyzed for inflammatory cell content, growth factor production, reepithelialization, collagen synthesis, and angiogenesis at multiple time points after injury. Compared to control mice, thrombocytopenic mice exhibited significantly altered wound inflammation. Wounds of thrombocytopenic mice contained significantly more macrophages and T cells, yet exhibited neutrophil content similar to wounds from control mice. Surprisingly, thrombocytopenic mice exhibited no delay in the reparative aspects of wound healing. The rate of wound reepithelialization, collagen synthesis, and angiogenesis was nearly identical for thrombocytopenic and control mice. Analysis of vascular endothelial growth factor, fibroblast growth factor 2, transforming growth factor beta1, keratinocyte growth factor, and epidermal growth factor revealed no difference in the levels of these growth factors in the wounds of control and thrombocytopenic mice. Taken together, the results suggest that the presence of platelets may influence wound inflammation, but that platelets do not significantly affect the proliferative aspects of repair, including wound closure, angiogenesis, and collagen synthesis.

  14. Triiodothyronine (T3) inhibits hyaluronate synthesis in a human dermal equivalent by downregulation of HAS2.

    PubMed

    Pouyani, Tara; Sadaka, Basma H; Papp, Suzanne; Schaffer, Lana

    2013-03-01

    Triiodothyronine (T3) is a thyroid hormone that can have varying effects on skin. In order to assess the effects of T3 on the human dermis, we prepared dermal equivalents using neonatal dermal cells via the process of self-assembly in the presence of differing concentrations of T3. These dermal equivalents were prepared in the absence of serum and a three dimensional matrix allowing for the direct assessment of different concentrations of T3 on dermal extracellular matrix formation. Three different concentrations of T3 were chosen, 20 pM, which is part of the base medium, 0.2 nM T3 and 2 nM T3. We find that self-assembled dermal equivalents formed under these conditions show a progressive "thinning" with increasing T3 concentrations. While we observed no change in total collagen content, inhibition of hyaluronate (HA) synthesis was observed in the 0.2- and 2-nM T3 constructs as compared to the 20-pM construct. Other glycosaminoglycan synthesis was not affected by increasing T3 concentrations. In order to identify the gene(s) responsible for inhibition of HA synthesis in the 2-nM T3 dermal equivalent, we conducted a differential gene array analysis. The results of these experiments demonstrate the differential expression of 40 genes, of these, 34 were upregulated and 6 genes were downregulated. The results from these experiments suggest that downregulation of HAS2 may be responsible for inhibition of hyaluronate synthesis in the self-assembled 2-nM T3 human dermal matrix.

  15. Effect of silicone on the collagen fibrillogenesis and stability.

    PubMed

    Kadziński, Leszek; Prokopowicz, Magdalena; Jakóbkiewicz-Banecka, Joanna; Gabig-Cimińska, Magdalena; Łukasiak, Jerzy; Banecki, Bogdan

    2015-04-01

    Collagen, the most abundant protein in mammals, is able to form fibrils, which have central role in tissue repair, fibrosis, and tumor invasion. As a component of skin, tendons, and cartilages, this protein contacts with any implanted materials. An inherent problem associated with implanted prostheses is their propensity to be coated with host proteins shortly after implantation. Also, silicone implants undergoing relatively long periods of contact with blood can lead to formation of thrombi and emboli. In this paper, we demonstrate the existence of interactions between siloxanes and collagen. Low-molecular-weight cyclic siloxane (hexamethylcyclotrisiloxane-D3) and polydimethylsiloxanes (PDMS) forming linear chains, ranging in viscosity from 20 to 12,000 cSt, were analyzed. We show that D3 as well as short-chain PDMS interact with collagen, resulting in a decrease in fibrillogenesis. However, loss of collagen native structure does not occur because of these interactions. Rather, collagen seems to be sequestered in its native form in an interlayer formed by collagen-siloxane complexes. On the other hand, silicone molecules with longer chains (i.e., PDMS with viscosity of 1000 and 12,000 cSt, the highest viscosity analyzed here) demonstrate little interaction with this protein and do not seem to affect collagen activity.

  16. Collagen Expression in Fibroblasts with a Novel LMNA Mutation

    PubMed Central

    Nguyen, Desiree; Leistritz, Dru F.; Turner, Lesley; MacGregor, David; Ohson, Kamal; Dancey, Paul; Martin, George M.; Oshima, Junko

    2007-01-01

    Laminopathies are a group of genetic disorders caused by LMNA mutations; they include muscular dystrophies, lipodystrophies and progeroid syndromes. We identified a novel heterozygous LMNA mutation, L59R, in a patient with the general appearance of mandibuloacral dysplasia and progeroid features. Examination of the nuclei of dermal fibroblasts revealed the irregular morphology characteristic of LMNA mutant cells. The nuclear morphological abnormalities of LMNA mutant lymphoblastoid cell lines were less prominent compared to those of primary fibroblasts. Since it has been reported that progeroid features are associated with increased extracellular matrix in dermal tissues, we compared a subset of these components in fibroblast cultures from LMNA mutants with those of control fibroblasts. There was no evidence of intracellular accumulation or altered mobility of collagen chains, or altered conversion of procollagen to collagen, suggesting that skin fibroblast-mediated matrix production may not play a significant role in the pathogenesis of this particular laminopathy. PMID:17150192

  17. Collagen expression in fibroblasts with a novel LMNA mutation

    SciTech Connect

    Nguyen, Desiree; Leistritz, Dru F.; Turner, Lesley; MacGregor, David; Ohson, Kamal; Dancey, Paul; Martin, George M.; Oshima, Junko . E-mail: picard@u.washington.edu

    2007-01-19

    Laminopathies are a group of genetic disorders caused by LMNA mutations; they include muscular dystrophies, lipodystrophies, and progeroid syndromes. We identified a novel heterozygous LMNA mutation, L59R, in a patient with the general appearance of mandibuloacral dysplasia and progeroid features. Examination of the nuclei of dermal fibroblasts revealed the irregular morphology characteristic of LMNA mutant cells. The nuclear morphological abnormalities of LMNA mutant lymphoblastoid cell lines were less prominent compared to those of primary fibroblasts. Since it has been reported that progeroid features are associated with increased extracellular matrix in dermal tissues, we compared a subset of these components in fibroblast cultures from LMNA mutants with those of control fibroblasts. There was no evidence of intracellular accumulation or altered mobility of collagen chains, or altered conversion of procollagen to collagen, suggesting that skin fibroblast-mediated matrix production may not play a significant role in the pathogenesis of this particular laminopathy.

  18. The biocompatibility of titanium in a buffer solution: compared effects of a thin film of TiO2 deposited by MOCVD and of collagen deposited from a gel.

    PubMed

    Popescu, Simona; Demetrescu, Ioana; Sarantopoulos, Christos; Gleizes, Alain N; Iordachescu, Dana

    2007-10-01

    This study aims at evaluating the biocompatibility of titanium surfaces modified according two different ways: (i) deposition of a bio-inert, thin film of rutile TiO(2) by chemical vapour deposition (MOCVD), and (ii) biochemical treatment with collagen gel, in order to obtain a bio-interactive coating. Behind the comparison is the idea that either the bio-inert or the bio-active coating has specific advantages when applied to implant treatment, such as the low price of the collagen treatment for instance. The stability in buffer solution was evaluated by open circuit potential (OCP) for medium time and cyclic voltametry. The OCP stabilized after 5.10(4) min for all the specimens except the collagen treated sample which presented a stable OCP from the first minutes. MOCVD treated samples stabilized to more electropositive values. Numeric results were statistically analysed to obtain the regression equations for long time predictable evolution. The corrosion parameters determined from cyclic curves revealed that the MOCVD treatment is an efficient way to improve corrosion resistance. Human dermal fibroblasts were selected for cell culture tests, taking into account that these cells are present in all bio-interfaces, being the main cellular type of connective tissue. The cells grew on either type of surface without phenotype modification. From the reduction of yellow, water-soluble 3-(4,5-dimethyldiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT cytotoxicity test), MOCVD treated samples offer better viability than mechanically polished Ti and collagen treated samples as well. Cell spreading, as evaluated from microscope images processed by the program Sigma Scan, showed also enhancement upon surface modification. Depending on the experimental conditions, MOCVD deposited TiO(2) exhibits different nanostructures that may influence biological behaviour. The results demonstrate the capacity of integration in simulated physiologic liquids for an implant pretreated by

  19. Type IV collagen aggregates promote keratinocyte proliferation and formation of epidermal layer in human skin equivalents.

    PubMed

    Matsuura-Hachiya, Yuko; Arai, Koji Y; Muraguchi, Taichi; Sasaki, Tasuku; Nishiyama, Toshio

    2017-03-07

    Type IV collagen isolated from lens capsule without enzymatic treatment is known to form a gel under physiological condition and influences cellular activities. In case of human keratinocytes, the suppression of proliferation on reconstituted type IV collagen gels was reported in monolayer culture. In this study, we examined effects of type IV collagen isolated from porcine lens capsule on epidermal formation in human skin equivalents. Type IV collagen aggregates were prepared under the culture condition and the aggregates suppressed keratinocyte proliferation in monolayer culture as well as the culture on the gels. In human skin equivalents type IV collagen aggregates were reconstituted on the surface of contracted collagen gels containing human dermal fibroblasts and the keratinocytes were then cultured on the aggregates for 14 days. Interestingly, in human skin equivalents with type IV collagen aggregates, the BrdU-positive keratinocytes were increased and the thickness of the epidermal layer was around twice than that of control culture. Epidermal differentiation markers were expressed in the upper layer of the epidermis and the defined deposition of human basement membrane components were increased at the dermal-epidermal junction. These results indicate that the type IV collagen aggregates stimulate the proliferation of basal keratinocytes and improve the stratification of epidermal layers in human skin equivalents. This article is protected by copyright. All rights reserved.

  20. Differentiation within autologous fibrin scaffolds of porcine dermal cells with the mesenchymal stem cell phenotype.

    PubMed

    de la Puente, Pilar; Ludeña, Dolores; López, Marta; Ramos, Jennifer; Iglesias, Javier

    2013-02-01

    Porcine mesenchymal stem cells (pMSCs) are an attractive source of cells for tissue engineering because their properties are similar to those of human stem cells. pMSCs can be found in different tissues but their dermal origin has not been studied in depth. Additionally, MSCs differentiation in monolayer cultures requires subcultured cells, and these cells are at risk of dedifferentiation when implanting them into living tissue. Following this, we attempted to characterize the MSCs phenotype of porcine dermal cells and to evaluate their cellular proliferation and differentiation in autologous fibrin scaffolds (AFSs). Dermal biopsies and blood samples were obtained from 12 pigs. Dermal cells were characterized by flow cytometry. Frozen autologous plasma was used to prepare AFSs. pMSC differentiation was studied in standard structures (monolayers and pellets) and in AFSs. The pMSCs expressed the CD90 and CD29 markers of the mesenchymal lineage. AFSs afforded adipogenic, osteogenic and chondrogenic differentiation. The porcine dermis can be proposed to be a good source of MSCs with adequate proliferative capacity and a suitable expression of markers. The pMSCs also showed optimal proliferation and differentiation in AFSs, such that these might serve as a promising autologous and implantable material for use in tissue engineering.

  1. ISSUES IN DERMAL EXPOSURE OF INFANTS

    EPA Science Inventory

    Infants' dermal exposures to environmental contaminants are expected to be different and, in many cases, much higher than adults. Because of the potential importance of the dermal exposure route, there is currently a significant amount of work being conducted to reduce the uncer...

  2. Titanium surface topography affects collagen biosynthesis of adherent cells.

    PubMed

    Mendonça, Daniela B S; Miguez, Patrícia A; Mendonça, Gustavo; Yamauchi, Mitsuo; Aragão, Francisco J L; Cooper, Lyndon F

    2011-09-01

    Collagen-dependent microstructure and physicochemical properties of newly formed bone around implant surfaces represent key determinants of implant biomechanics. This study investigated the effects of implant surface topography on collagen biosynthesis of adherent human mesenchymal stem cells (hMSCs). hMSCs were grown for 0 to 42 days on titanium disks (20.0 × 1.0 mm) with smooth or rough surfaces. Cell attachment and spreading were evaluated by incubating cells with Texas-Red-conjugated phalloidin antibody. Quantitative real-time PCR was used to measure the mRNA levels of Col1α1 and collagen modifying genes including prolyl hydroxylases (PHs), lysyl oxidases (LOXs) and lysyl hydroxylases (LHs). Osteogenesis was assessed at the level of osteoblast specific gene expression and alizarin red staining for mineralization. Cell layer-associated matrix and collagen content were determined by amino acid analysis. At 4h, 100% cells were flattened on both surfaces, however the cells on smooth surface had a fibroblast-like shape, while cells on rough surface lacked any defined long axis. PH, LH, and most LOX mRNA levels were greater in hMSCs grown on rough surfaces for 3 days. The mineralized area was greater for rough surface at 28 and 42 days. The collagen content (percent total protein) was also greater at rough surface compared to smooth surface at 28 (36% versus 26%) and 42 days (46% versus 29%), respectively (p<.05). In a cell culture model, rough surface topography positively modulates collagen biosynthesis and accumulation and the expression of genes associated with collagen cross-linking in adherent hMSC. The altered biosynthesis of the collagen-rich ECM adjacent to endosseous implants may influence the biomechanical properties of osseointegrated endosseous implants.

  3. Factors affecting the mechanical behavior of collagen hydrogels for skin tissue engineering.

    PubMed

    Pensalfini, Marco; Ehret, Alexander E; Stüdeli, Silvia; Marino, Daniela; Kaech, Andres; Reichmann, Ernst; Mazza, Edoardo

    2017-05-01

    The effect of the production factors yielding a functional dermal substitute was investigated by means of monotonic and cyclic uniaxial tensile tests, as well as electron microscopy visualizations. The role of (i) plastic compression, (ii) product incubation, and (iii) cell permanence in the collagenous matrix in order to achieve a skin-like behavior were characterized in terms of material and structural stiffness, in-plane kinematics, and cyclic response, as well as pore size and network density. The plastic compression resulted in a denser and stiffer material, while no corresponding change was observed in the behavior of the entire structure. This was related to the progressive reduction in product thickness and amount of excess water, rather than to formation of new crosslinks between fibers. Contrary, irrespective of the presence of human fibroblasts, the product incubation induced both material and structural stiffening, indicating the formation of a denser network. These results were confirmed by similar evolutions in the construct in-plane kinematics and cyclic stress reduction. Finally, comparison of constructs incubated in different culture media indicated a determinant contribution of the biochemical environment, rather than of the seeded cells, to the achieved mechanical properties. The observed features are relevant in terms of mechanical biocompatibility of the implant and might direct future optimizations of the production process in order to rapidly attain the desired mechanical properties.

  4. Differentiation of human umbilical cord mesenchymal stem cells into dermal fibroblasts in vitro

    SciTech Connect

    Han, Yanfu; Chai, Jiake; Sun, Tianjun; Li, Dongjie; Tao, Ran

    2011-10-07

    Highlights: {yields} Mesenchymal stem cells (MSCs) are potential seed cells for tissue-engineered skin. {yields} Tissue-derived umbilical cord MSCs (UCMSCs) can readily be isolated in vitro. {yields} We induce UCMSCs to differentiate into dermal fibroblasts via conditioned medium. {yields} Collagen type I and collagen type III mRNA level was higher in differentiated cells. {yields} UCMSCs-derived fibroblast-like cells strongly express fibroblast-specific protein. -- Abstract: Tissue-derived umbilical cord mesenchymal stem cells (UCMSCs) can be readily obtained, avoid ethical or moral constraints, and show excellent pluripotency and proliferation potential. UCMSCs are considered to be a promising source of stem cells in regenerative medicine. In this study, we collected newborn umbilical cord tissue under sterile conditions and isolated UCMSCs through a tissue attachment method. UCMSC cell surface markers were examined using flow cytometry. On the third passage, UCMSCs were induced to differentiate into dermal fibroblasts in conditioned induction media. The induction results were detected using immunofluorescence with a fibroblast-specific monoclonal antibody and real time PCR for type I and type III collagen. UCMSCs exhibited a fibroblast-like morphology and reached 90% confluency 14 to 18 days after primary culture. Cultured UCMSCs showed strong positive staining for CD73, CD29, CD44, CD105, and HLA-I, but not CD34, CD45, CD31, or HLA-DR. After differentiation, immunostaining for collagen type I, type III, fibroblast-specific protein, vimentin, and desmin were all strongly positive in induced cells, and staining was weak or negative in non-induced cells; total transcript production of collagen type I and collagen type III mRNA was higher in induced cells than in non-induced cells. These results demonstrate that UCMSCs can be induced to differentiate into fibroblasts with conditioned induction media and, in turn, could be used as seed cells for tissue

  5. Cell therapy for full-thickness wounds: are fetal dermal cells a potential source?

    PubMed

    Akershoek, J J; Vlig, M; Talhout, W; Boekema, B K H L; Richters, C D; Beelen, R H J; Brouwer, K M; Middelkoop, E; Ulrich, M M W

    2016-04-01

    The application of autologous dermal fibroblasts has been shown to improve burn wound healing. However, a major hurdle is the availability of sufficient healthy skin as a cell source. We investigated fetal dermal cells as an alternative source for cell-based therapy for skin regeneration. Human (hFF), porcine fetal (pFF) or autologous dermal fibroblasts (AF) were seeded in a collagen-elastin substitute (Novomaix, NVM), which was applied in combination with an autologous split thickness skin graft (STSG) to evaluate the effects of these cells on wound healing in a porcine excisional wound model. Transplantation of wounds with NVM+hFF showed an increased influx of inflammatory cells (e.g., neutrophils, macrophages, CD4(+) and CD8(+) lymphocytes) compared to STSG, acellular NVM (Acell-NVM) and NVM+AF at post-surgery days 7 and/or 14. Wounds treated with NVM+pFF presented only an increase in CD8(+) lymphocyte influx. Furthermore, reduced alpha-smooth muscle actin (αSMA) expression in wound areas and reduced contraction of the wounds was observed with NVM+AF compared to Acell-NVM. Xenogeneic transplantation of NVM+hFF increased αSMA expression in wounds compared to NVM+AF. An improved scar quality was observed for wounds treated with NVM+AF compared to Acell-NVM, NVM+hFF and NVM+pFF at day 56. In conclusion, application of autologous fibroblasts improved the overall outcome of wound healing in comparison to fetal dermal cells and Acell-NVM, whereas application of fetal dermal fibroblasts in NVM did not improve wound healing of full-thickness wounds in a porcine model. Although human fetal dermal cells demonstrated an increased immune response, this did not seem to affect scar quality.

  6. Fabrication and biocompatibility of collagen sponge reinforced with poly(glycolic acid) fiber.

    PubMed

    Hiraoka, Yosuke; Kimura, Yu; Ueda, Hiroki; Tabata, Yasuhiko

    2003-12-01

    This article describes an investigation of collagen sponge mechanically reinforced through the incorporation of poly(glycolic acid) (PGA) fiber. A collagen solution with PGA fiber homogeneously dispersed at collagen:PGA weight ratios of 1.5, 0.8, 0.4, and 0.2 was freeze-dried, followed by dehydrothermal cross-linking to obtain collagen sponges incorporating PGA fiber to various extents. By scanning electron microscopy observation, the collagen sponges exhibited isotropic and interconnected pore structures with an average size of 180 microm, irrespective of PGA fiber incorporation. As expected, PGA fiber incorporation enabled the collagen sponges to significantly enhance their compression strength. In vitro cell culture studies revealed that the number of L929 fibroblasts initially attached was significantly greater for any collagen sponge incorporating PGA fiber than for collagen sponge. The shrinkage of sponge after cell seeding was suppressed by fiber incorporation. It is possible that shrinkage suppression results in the superior cell attachment of sponge incorporating PGA fiber. After subcutaneous implantation into the backs of mice, the residual volume of collagen sponge incorporating PGA fiber was significant compared with that of collagen sponge and increased with a decrease in the collagen:PGA ratio. The greater number of cells infiltrated and deeper infiltration were observed for collagen sponge incorporating PGA fiber implanted subcutaneously. We conclude that the incorporation of PGA fiber is a simple and promising way to reinforce collagen sponge without impairing biocompatibility.

  7. Collagen-mediated hemostasis.

    PubMed

    Manon-Jensen, T; Kjeld, N G; Karsdal, M A

    2016-03-01

    Collagens mediate essential hemostasis by maintaining the integrity and stability of the vascular wall. Imbalanced turnover of collagens by uncontrolled formation and/or degradation may result in pathologic conditions such as fibrosis. Thickening of the vessel wall because of accumulation of collagens may lead to arterial occlusion or thrombosis. Thinning of the wall because of collagen degradation or deficiency may lead to rupture of the vessel wall or aneurysm. Preventing excessive hemorrhage or thrombosis relies on collagen-mediated actions. Von Willebrand factor, integrins and glycoprotein VI, as well as clotting factors, can bind collagen to restore normal hemostasis after trauma. This review outlines the essential roles of collagens in mediating hemostasis, with a focus on collagens types I, III, IV, VI, XV, and XVIII.

  8. Biomedical applications of collagens.

    PubMed

    Ramshaw, John A M

    2016-05-01

    Collagen-based biomedical materials have developed into important, clinically effective materials used in a range of devices that have gained wide acceptance. These devices come with collagen in various formats, including those based on stabilized natural tissues, those that are based on extracted and purified collagens, and designed composite, biosynthetic materials. Further knowledge on the structure and function of collagens has led to on-going developments and improvements. Among these developments has been the production of recombinant collagen materials that are well defined and are disease free. Most recently, a group of bacterial, non-animal collagens has emerged that may provide an excellent, novel source of collagen for use in biomaterials and other applications. These newer collagens are discussed in detail. They can be modified to direct their function, and they can be fabricated into various formats, including films and sponges, while solutions can also be adapted for use in surface coating technologies.

  9. Spatio-temporal modification of collagen scaffolds mediated by triple helical propensity.

    PubMed

    Wang, Allen Y; Foss, Catherine A; Leong, Shirley; Mo, Xiao; Pomper, Martin G; Yu, Seungju M

    2008-07-01

    Functionalized collagen that incorporates exogenous compounds may offer new and improved biomaterials applications, especially in drug-delivery, multifunctional implants, and tissue engineering. To that end, we developed a specific and reversible collagen modification technique utilizing associative chain interactions between synthetic collagen mimetic peptide (CMP) [(ProHypGly) chi; Hyp = hydroxyproline] and type I collagen. Here we show temperature-dependent collagen binding and subsequent release of a series of CMPs with varying chain lengths indicating a triple helical propensity driven binding mechanism. The binding took place when melted, single-strand CMPs were allowed to fold while in contact with reconstituted type I collagens. The binding affinity is highly specific to collagen as labeled CMP bound to nanometer scale periodic positions on type I collagen fibers and could be used to selectively image collagens in ex vivo human liver tissue. When heated to physiological temperature, bound CMPs discharged from the collagen at a sustained rate that correlated with CMP's triple helical propensity, suggesting that sustainability is mediated by dynamic collagen-CMP interactions. We also report on the spatially defined modification of collagen film with linear and multi-arm poly(ethylene glycol)-CMP conjugates; at 37 degrees C, these PEG-CMP conjugates exhibited temporary cell repelling activity lasting up to 9 days. These results demonstrate new opportunities for targeting pathologic collagens for diagnostic or therapeutic applications and for fabricating multifunctional collagen coatings and scaffolds that can temporally and spatially control the behavior of cells associated with the collagen matrices.

  10. Species Typing in Dermal Leishmaniasis

    PubMed Central

    Dujardin, Jean-Claude

    2015-01-01

    SUMMARY Leishmania is an infectious protozoan parasite related to African and American trypanosomes. All Leishmania species that are pathogenic to humans can cause dermal disease. When one is confronted with cutaneous leishmaniasis, identification of the causative species is relevant in both clinical and epidemiological studies, case management, and control. This review gives an overview of the currently existing and most used assays for species discrimination, with a critical appraisal of the limitations of each technique. The consensus taxonomy for the genus is outlined, including debatable species designations. Finally, a numerical literature analysis is presented that describes which methods are most used in various countries and regions in the world, and for which purposes. PMID:25672782

  11. [Cutaneous ultrasound and dermal fillers].

    PubMed

    Villegas Fernández, C; Burón Álvarez, I; Fernández-Tresguerres Centeno, A; Alfageme Roldán, F; de Cabo Francés, F

    2015-11-01

    Requests for fillers or dermatological implants have dramatically increased in dermatology consultations in the last few years, either for the correction of superficial age-related wrinkles and cutaneous creases or to increase the volume of specific areas (cheeks, lips...). Dermatologists are often the first professionals to provide these treatments. Nevertheless, in other situations, the patients have already been treated, and many of them do not know the type of material that has been implanted or may even deny previous treatment, even when evident on clinical examination. In these occasions, cutaneous ultrasound is an effective and reliable tool for the real-time diagnosis of the kind of implant that has been used, its location, and the study of its possible complications.

  12. Type II achondrogenesis-hypochondrogenesis: identification of abnormal type II collagen.

    PubMed

    Godfrey, M; Hollister, D W

    1988-12-01

    We have extended the study of a mild case of type II achondrogenesis-hypochondrogenesis to include biochemical analyses of cartilage, bone, and the collagens produced by dermal fibroblasts. Type I collagen extracted from bone and types I and III collagen produced by dermal fibroblasts were normal, as was the hexosamine ratio of cartilage proteoglycans. Hyaline cartilage, however, contained approximately equal amounts of types I and II collagen and decreased amounts of type XI collagen. Unlike the normal SDS-PAGE mobility. Two-dimensional SDS-PAGE revealed extensive overmodification of all type II cyanogen bromide peptides in a pattern consistent with heterozygosity for an abnormal pro alpha 1(II) chain which impaired the assembly and/or folding of type II collagen. This interpretation implies that dominant mutations of the COL2A1 gene may cause type II achondrogenesis-hypochondrogenesis. More generally, emerging data implicating defects of type II collagen in the type II achondrogenesis-hypochondrogenesis-spondyloepiphyseal dysplasia congenita spectrum and in the Kniest-Stickler syndrome spectrum suggest that diverse mutations of this gene may be associated with widely differing phenotypic outcome.

  13. Differentiation within autologous fibrin scaffolds of porcine dermal cells with the mesenchymal stem cell phenotype

    SciTech Connect

    Puente, Pilar de la

    2013-02-01

    Porcine mesenchymal stem cells (pMSCs) are an attractive source of cells for tissue engineering because their properties are similar to those of human stem cells. pMSCs can be found in different tissues but their dermal origin has not been studied in depth. Additionally, MSCs differentiation in monolayer cultures requires subcultured cells, and these cells are at risk of dedifferentiation when implanting them into living tissue. Following this, we attempted to characterize the MSCs phenotype of porcine dermal cells and to evaluate their cellular proliferation and differentiation in autologous fibrin scaffolds (AFSs). Dermal biopsies and blood samples were obtained from 12 pigs. Dermal cells were characterized by flow cytometry. Frozen autologous plasma was used to prepare AFSs. pMSC differentiation was studied in standard structures (monolayers and pellets) and in AFSs. The pMSCs expressed the CD90 and CD29 markers of the mesenchymal lineage. AFSs afforded adipogenic, osteogenic and chondrogenic differentiation. The porcine dermis can be proposed to be a good source of MSCs with adequate proliferative capacity and a suitable expression of markers. The pMSCs also showed optimal proliferation and differentiation in AFSs, such that these might serve as a promising autologous and implantable material for use in tissue engineering. -- Highlights: ► Low fibrinogen concentration provides a suitable matrix for cell migration and differentiation. ► Autologous fibrin scaffolds is a promising technique in tissue engineering. ► Dermal cells are an easily accessible mesenchymal stem cell source. ► Fibrin scaffolds afforded adipogenic, osteogenic and chondrogenic differentiation.

  14. Composite cell support membranes based on collagen and polycaprolactone for tissue engineering of skin.

    PubMed

    Dai, N-T; Williamson, M R; Khammo, N; Adams, E F; Coombes, A G A

    2004-08-01

    The preparation and characterisation of collagen:PCL composites for manufacture of tissue engineered skin substitutes and models are reported. Films having collagen:PCL (w/w) ratios of 1:4, 1:8 and 1:20 were prepared by impregnation of lyophilised collagen mats by PCL solutions followed by solvent evaporation. In vitro assays of collagen release and residual collagen content revealed an expected inverse relationship between the collagen release rate and the content of synthetic polymer in the composite that may be exploited for controlled presentation and release of biopharmaceuticals such as growth factors. DSC analysis revealed the characteristic melting point of PCL at around 60 degrees C and a tendency for the collagen component, at high loading, to impede crystallinity development within the PCL phase. The preparation of fibroblast/composite constructs was investigated using cell culture as a first stage in mimicking the dermal/epidermal structure of skin. Fibroblasts were found to attach and proliferate on all the composites investigated reaching a maximum of 2 x 10(5)/cm(2) on 1:20 collagen:PCL materials at day 8 with cell numbers declining thereafter. Keratinocyte growth rates were similar on all types of collagen:PCL materials investigated reaching a maximum of 6.6 x 10(4)/cm(2) at day 6. The results revealed that composite films of collagen and PCL are favourable substrates for growth of fibroblasts and keratinocytes and may find utility for skin repair.

  15. Antioxidant Nanoplatforms for Dermal Delivery: Melatonin.

    PubMed

    Milán, Aroha Belen Sánchez; Campmany, Ana C Calpena; Naveros, Beatriz Clares

    2017-02-22

    Melatonin (MLT) is emerging as a promising therapeutic agent, mainly due to its role as antioxidant. Substantial evidences show that melatonin is potentially effective on a variety of diseases as cancer, inflammation and neurodegenerative diseases. The excellent antioxidant capacity with pharmacokinetics characteristics and the emerging search for new pharmaceutical nanotechnology based systems, make it particularly attractive to elaborate nanoplatforms based on MLT for biomedical or cosmetic dermal applications. Different nanosystems for dermal delivery have been investigated. These nanosystems are expected to play a significant role in the protection of therapeutic functions of MLT, enhanced transdermal permeability and dermal delivery profiles. These nanocarriers not only transport MLT, but also increase the solubility, bioavailability, half-life and antioxidant activity. In the current review, we will focus on nanocarrier production strategies, dermal MLT application and delivery advances in vivo and in vitro. Equally, future perspectives of this assisted MLT delivery will be also discussed.

  16. Cochlear Implants.

    ERIC Educational Resources Information Center

    Clark, Catherine; Scott, Larry

    This brochure explains what a cochlear implant is, lists the types of individuals with deafness who may be helped by a cochlear implant, describes the process of evaluating people for cochlear implants, discusses the surgical process for implanting the aid, traces the path of sound through the cochlear implant to the brain, notes the costs of…

  17. Assessment of dermal exposure and histopathologic changes of different sized nano-silver in healthy adult rabbits

    NASA Astrophysics Data System (ADS)

    kazem Koohi, Mohammad; Hejazy, Marzie; Asadi, Farzad; Asadian, Peyman

    2011-07-01

    The purpose of this study is to evaluate the dermal toxicity (Irritation/Corrosion) of three sizes of nanosilver particles (10, 20 and 30 nm) during 3 min, 1 and 4 hours according to the OECD/OCDE guideline Histopathological effects in secondary organs from liver, kidney, heart, spleen and brain 14 day post dermal administration are also reported. 10 and 20 nm Ag nanoparticles treated group showed well defined dermal erythema and oedema. Histopathological findings of 10 and 20 nm (4 hours exposure) on 14-day post dermal administration showed hyperkeratosis, acanthosis, hair-filled follicles and papillomatosis in an irregular epidermis, fibrosis, hyperemia, erythema, intracellular oedema and hyalinisation of collagen in dermis of skin. Liver revealed midzonal and periacinar necrosis, portal mononuclear infiltration, liver fatty change, liver congestion and hyperemic central vein. Splenic red pulp congestion and white pulp hyperreactivity, splenic trabeculae and sinusoidal congestion and hyaline change were found in spleen. Fatty degeneration in some cardiovascular cells and subendocardial hemorrhage without inflammation was perceived. Picnotic appearance of pyramidal neurons in the brain cortex, gliosis and mild perineuronal oedema ischemic cell change and hyperemic meninges was observed in brain. Our research concluded that dermal exposure to lesser sizes of silver nanoparticles is more disastrous than greater ones.

  18. Development of dermal denticles in skates (Chondrichthyes, Batoidea): patterning and cellular differentiation.

    PubMed

    Miyake, T; Vaglia, J L; Taylor, L H; Hall, B K

    1999-07-01

    Patterning, cellular differentiation, and developmental sequences of dermal denticles (denticles) are described for the skate Leucoraja erinacea. Development of denticles proceeds caudo-rostrally in the tail and trunk. Once three rows of denticles form in the tail and trunk, denticles begin to appear in the region of the pelvic girdle, medio-caudal to the eyes and on the pectoral fins. Although timing of cellular differentiation of denticles differs among different locations of the body, cellular development of a denticle is identical in all locations. Thickening of the epidermis as a denticle lamina marks initiation of development. A single lamina for each denticle forms, and a small group of mesenchymal cells aggregates underneath it. The lamina then invaginates caudo-rostrally to form the inner- and outer-denticle epithelia (IDE and ODE, respectively). Before nuclei of IDE cells are polarized, enameloid matrix appears between the basement membrane of the IDE and the apical surface of the pre-odontoblasts. Pre-dentin is then laid down along with collagenous materials. Von Kossa stain visualizes initial mineralization of dentin, but not enameloid. During the growth of a denticle, dense fibrous connective tissue of the dermis forms the deep dermal tissue over the dorsal musculature. Attachment fibers and tendons anchor denticles and dorsal musculature, respectively, on deep dermal tissue. Basal tissue of the denticles develops as the denticle crown grows. If the basal tissue is bone of attachment, then the cells along the basal tissue would be osteoblasts. However, these cells could not be distinguished from odontoblasts using immunolocalization of type I pro-collagen (Col I), alkaline phosphatase (APase), and neural cell adhesion molecule (N-CAM). Well-developed dentin, (not pre-dentin), the enameloid matrix (probably when it begins to mineralize), and deep dermal tissue are Verhoeff stain-positive, suggesting that these tissues contain elastin and/or elastin

  19. Dermal filler complications: a clinicopathologic study with a spectrum of histologic reaction patterns.

    PubMed

    El-Khalawany, Mohamed; Fawzy, Sameh; Saied, Asmaa; Al Said, Mohammed; Amer, Ahmed; Eassa, Bayoumi

    2015-02-01

    Although dermal fillers are generally accepted as safe and well-tolerable cosmetic tools, adverse reaction still forms a prognostic problem. The aim of this study was to demonstrate the clinicopathologic patterns of dermal filler complications in our center. A 5-year single-center study that included patients complained from filler complications and referred to the dermatopathology unit in Al-Azhar University for histologic assessment. The study included 38 female patients with an average age of 47 years. The mean onset of complications was 14.6 ± 5.27 months after injection. The injected material included hyaluronic acid (18.4%), silicone (52.6%), bovine collagen (15.8%) and polyacrylamide hydrogel (13.2%). Most lesions were located on the face (55.3%), less commonly on the hands (18.4%), buttocks (21%), and rarely on the vulva (5.3%). The clinical spectrum included indurated plaque (23.7%), nodular lesion (31.6%), inflammatory mass (15.8%), atrophic lesion (10.5%), skin discoloration (13.1%) and ulceration (5.3%). Histologically, granulomatous reaction was the major finding, either a foreign body granuloma (34.2%) or infectious granuloma (13.2%). Other histologic reactions included dermal pseudocysts with chronic inflammation (26.3%), dermal fibrosis (15.8%), and eosinophilic panniculitis (10.5%). Our results confirmed that dermal fillers could be manifested with variable clinical presentations and show different histologic reactions. Because of long-standing duration until complications occur, history taking is crucial and should be emphasized in every suspected patient. It is hoped that this article will increase awareness for recognition of these variable complications and help select the appropriate therapy.

  20. TRPV4 ion channel is a novel regulator of dermal myofibroblast differentiation.

    PubMed

    Sharma, Shweta; Goswami, Rishov; Merth, Michael; Cohen, Jonathan; Lei, Kai Y; Zhang, David X; Rahaman, Shaik O

    2017-03-01

    Scleroderma is a multisystem fibroproliferative disease with no effective medical treatment. Myofibroblasts are critical to the fibrogenic tissue repair process in the skin and many internal organs. Emerging data support a role for both matrix stiffness, and transforming growth factor β1 (TGFβ1), in myofibroblast differentiation. Transient receptor potential vanilloid 4 (TRPV4) is a mechanosensitive ion channel activated by both mechanical and biochemical stimuli. The objective of this study was to determine the role of TRPV4 in TGFβ1- and matrix stiffness-induced differentiation of dermal fibroblasts. We found that TRPV4 channels are expressed and functional in both human (HDF) and mouse (MDF) dermal fibroblasts. TRPV4 activity (agonist-induced Ca(2+) influx) was induced by both matrix stiffness and TGFβ1 in dermal fibroblasts. TGFβ1 induced expression of TRPV4 proteins in a dose-dependent manner. Genetic ablation or pharmacologic antagonism of TRPV4 channel abrogated Ca(2+) influx and both TGFβ1-induced and matrix stiffness-induced myofibroblast differentiation as assessed by i) α-smooth muscle actin expression/incorporation into stress fibers, ii) generation of polymerized actin, and iii) expression of collagen-1. We found that TRPV4 inhibition abrogated TGFβ1-induced activation of AKT but not of Smad2/3, suggesting that the mechanism by which profibrotic TGFβ1 signaling in dermal fibroblasts is modified by TRPV4 may be through non-Smad pathways. Altogether, these data identify a novel reciprocal functional link between TRPV4 activation and TGFβ1 signals regulating dermal myofibroblast differentiation. These findings suggest that therapeutic inhibition of TRPV4 activity may provide a targeted approach to the treatment of scleroderma.

  1. Three Dimensional Collagen Scaffold Promotes Intrinsic Vascularisation for Tissue Engineering Applications.

    PubMed

    Chan, Elsa C; Kuo, Shyh-Ming; Kong, Anne M; Morrison, Wayne A; Dusting, Gregory J; Mitchell, Geraldine M; Lim, Shiang Y; Liu, Guei-Sheung

    2016-01-01

    Here, we describe a porous 3-dimensional collagen scaffold material that supports capillary formation in vitro, and promotes vascularization when implanted in vivo. Collagen scaffolds were synthesized from type I bovine collagen and have a uniform pore size of 80 μm. In vitro, scaffolds seeded with primary human microvascular endothelial cells suspended in human fibrin gel formed CD31 positive capillary-like structures with clear lumens. In vivo, after subcutaneous implantation in mice, cell-free collagen scaffolds were vascularized by host neovessels, whilst a gradual degradation of the scaffold material occurred over 8 weeks. Collagen scaffolds, impregnated with human fibrinogen gel, were implanted subcutaneously inside a chamber enclosing the femoral vessels in rats. Angiogenic sprouts from the femoral vessels invaded throughout the scaffolds and these degraded completely after 4 weeks. Vascular volume of the resulting constructs was greater than the vascular volume of constructs from chambers implanted with fibrinogen gel alone (42.7±5.0 μL in collagen scaffold vs 22.5±2.3 μL in fibrinogen gel alone; p<0.05, n = 7). In the same model, collagen scaffolds seeded with human adipose-derived stem cells (ASCs) produced greater increases in vascular volume than did cell-free collagen scaffolds (42.9±4.0 μL in collagen scaffold with human ASCs vs 25.7±1.9 μL in collagen scaffold alone; p<0.05, n = 4). In summary, these collagen scaffolds are biocompatible and could be used to grow more robust vascularized tissue engineering grafts with improved the survival of implanted cells. Such scaffolds could also be used as an assay model for studies on angiogenesis, 3-dimensional cell culture, and delivery of growth factors and cells in vivo.

  2. Comparison of Calcium and Barium Microcapsules as Scaffolds in the Development of Artificial Dermal Papillae

    PubMed Central

    Liu, Yang; Lin, Changmin; Zeng, Yang; Li, Haihong; Cai, Bozhi; Huang, Keng; Yuan, Yanping; Li, Yu

    2016-01-01

    This study aimed to develop and evaluate barium and calcium microcapsules as candidates for scaffolding in artificial dermal papilla. Dermal papilla cells (DPCs) were isolated and cultured by one-step collagenase treatment. The DPC-Ba and DPC-Ca microcapsules were prepared by using a specially designed, high-voltage, electric-field droplet generator. Selected microcapsules were assessed for long-term inductive properties with xenotransplantation into Sprague-Dawley rat ears. Both barium and calcium microcapsules maintained xenogenic dermal papilla cells in an immunoisolated environment and induced the formation of hair follicle structures. Calcium microcapsules showed better biocompatibility, permeability, and cell viability in comparison with barium microcapsules. Before 18 weeks, calcium microcapsules gathered together, with no substantial immune response. After 32 weeks, some microcapsules were near inflammatory cells and wrapped with fiber. A few large hair follicles were found. Control samples showed no marked changes at the implantation site. Barium microcapsules were superior to calcium microcapsules in structural and mechanical stability. The cells encapsulated in hydrogel barium microcapsules exhibited higher short-term viability. This study established a model to culture DPCs in 3D culture conditions. Barium microcapsules may be useful in short-term transplantation study. Calcium microcapsules may provide an effective scaffold for the development of artificial dermal papilla. PMID:27123456

  3. Comparison of Calcium and Barium Microcapsules as Scaffolds in the Development of Artificial Dermal Papillae.

    PubMed

    Liu, Yang; Lin, Changmin; Zeng, Yang; Li, Haihong; Cai, Bozhi; Huang, Keng; Yuan, Yanping; Li, Yu

    2016-01-01

    This study aimed to develop and evaluate barium and calcium microcapsules as candidates for scaffolding in artificial dermal papilla. Dermal papilla cells (DPCs) were isolated and cultured by one-step collagenase treatment. The DPC-Ba and DPC-Ca microcapsules were prepared by using a specially designed, high-voltage, electric-field droplet generator. Selected microcapsules were assessed for long-term inductive properties with xenotransplantation into Sprague-Dawley rat ears. Both barium and calcium microcapsules maintained xenogenic dermal papilla cells in an immunoisolated environment and induced the formation of hair follicle structures. Calcium microcapsules showed better biocompatibility, permeability, and cell viability in comparison with barium microcapsules. Before 18 weeks, calcium microcapsules gathered together, with no substantial immune response. After 32 weeks, some microcapsules were near inflammatory cells and wrapped with fiber. A few large hair follicles were found. Control samples showed no marked changes at the implantation site. Barium microcapsules were superior to calcium microcapsules in structural and mechanical stability. The cells encapsulated in hydrogel barium microcapsules exhibited higher short-term viability. This study established a model to culture DPCs in 3D culture conditions. Barium microcapsules may be useful in short-term transplantation study. Calcium microcapsules may provide an effective scaffold for the development of artificial dermal papilla.

  4. Synergistic effect of vitamin D and low concentration of transforming growth factor beta 1, a potential role in dermal wound healing.

    PubMed

    Ding, Jie; Kwan, Peter; Ma, Zengshuan; Iwashina, Takashi; Wang, Jianfei; Shankowsky, Heather A; Tredget, Edward E

    2016-09-01

    Dermal wound healing, in which transforming growth factor beta 1 (TGFβ1) plays an important role, is a complex process. Previous studies suggest that vitamin D has a potential regulatory role in TGFβ1 induced activation in bone formation, and there is cross-talk between their signaling pathways, but research on their effects in other types of wound healing is limited. The authors therefore wanted to explore the role of vitamin D and its interaction with low concentration of TGFβ1 in dermal fibroblast-mediated wound healing through an in vitro study. Human dermal fibroblasts were treated with vitamin D, TGFβ1, both, or vehicle, and then the wound healing functions of dermal fibroblasts were measured. To further explore possible mechanisms explaining the synergistic effect of vitamin D and TGFβ1, targeted gene silencing of the vitamin D receptor was performed. Compared to either factor alone, treatment of fibroblasts with both vitamin D and low concentration of TGFβ1 increased gene expression of TGFβ1, connective tissue growth factor, and fibronectin 1, and enhanced fibroblast migration, myofibroblast formation, and collagen production. Vitamin D receptor gene silencing blocked this synergistic effect of vitamin D and TGFβ1 on both collagen production and myofibroblast differentiation. Thus a synergistic effect of vitamin D and low TGFβ1 concentration was found in dermal fibroblast-mediated wound healing in vitro. This study suggests that supplementation of vitamin D may be an important step to improve wound healing and regeneration in patients with a vitamin D deficiency.

  5. Cutaneous collagenous vasculopathy: A rare case report

    PubMed Central

    Rambhia, Kinjal Deepak; Hadawale, Snehal D.; Khopkar, Uday S.

    2016-01-01

    Cutaneous collagenous vasculopathy (CCV) is a distinct, rare, and underdiagnosed condition. We report a case of CCV in a 50-year-old woman presenting as asymptomatic, erythematous to hyperpigmented nonblanchable macules over both the lower extremities. The clinical differential diagnosis of the lesions was pigmented purpuric dermatoses (Schamberg's purpura) and cutaneous small vessel vasculitis. Histology of the lesions revealed dilated superficial dermal vessels with abundant pink hyaline material in the vessel wall, which stained with periodic acid Schiff stain. The patient was diagnosed as CCV. This condition remains largely underdiagnosed and is commonly mistaken for pigmented purpuric dermatosis or generalized essential telangiectasia. Emphasis on the differentiation of CCV from its clinical and histological mimicks is made. PMID:26955587

  6. Enigmatic insight into collagen

    PubMed Central

    Deshmukh, Shrutal Narendra; Dive, Alka M; Moharil, Rohit; Munde, Prashant

    2016-01-01

    Collagen is a unique, triple helical molecule which forms the major part of extracellular matrix. It is the most abundant protein in the human body, representing 30% of its dry weight. It is the fibrous structural protein that makes up the white fibers (collagen fibers) of skin, tendons, bones, cartilage and all other connective tissues. Collagens are not only essential for the mechanical resistance and resilience of multicellular organisms, but are also signaling molecules defining cellular shape and behavior. The human body has at least 16 types of collagen, but the most prominent types are I, II and III. Collagens are produced by several cell types and are distinguishable by their molecular compositions, morphologic characteristics, distribution, functions and pathogenesis. This is the major fibrous glycoprotein present in the extracellular matrix and in connective tissue and helps in maintaining the structural integrity of these tissues. It has a triple helical structure. Various studies have proved that mutations that modify folding of the triple helix result in identifiable genetic disorders. Collagen diseases share certain similarities with autoimmune diseases, because autoantibodies specific to each collagen disease are produced. Therefore, this review highlights the role of collagen in normal health and also the disorders associated with structural and functional defects in collagen. PMID:27601823

  7. Collagen and gelatin.

    PubMed

    Liu, Dasong; Nikoo, Mehdi; Boran, Gökhan; Zhou, Peng; Regenstein, Joe M

    2015-01-01

    Collagen and gelatin have been widely used in the food, pharmaceutical, and cosmetic industries due to their excellent biocompatibility, easy biodegradability, and weak antigenicity. Fish collagen and gelatin are of renewed interest, owing to the safety and religious concerns of their mammalian counterparts. The structure of collagen has been studied using various modern technologies, and interpretation of the raw data should be done with caution. The structure of collagen may vary with sources and seasons, which may affect its applications and optimal extraction conditions. Numerous studies have investigated the bioactivities and biological effects of collagen, gelatin, and their hydrolysis peptides, using both in vitro and in vivo assay models. In addition to their established nutritional value as a protein source, collagen and collagen-derived products may exert various potential biological activities on cells in the extracellular matrix through the corresponding food-derived peptides after ingestion, and this might justify their applications in dietary supplements and pharmaceutical preparations. Moreover, an increasing number of novel applications have been found for collagen and gelatin. Therefore, this review covers the current understanding of the structure, bioactivities, and biological effects of collagen, gelatin, and gelatin hydrolysates as well as their most recent applications.

  8. Collagen XII and XIV, new partners of cartilage oligomeric matrix protein in the skin extracellular matrix suprastructure.

    PubMed

    Agarwal, Pallavi; Zwolanek, Daniela; Keene, Douglas R; Schulz, Jan-Niklas; Blumbach, Katrin; Heinegård, Dick; Zaucke, Frank; Paulsson, Mats; Krieg, Thomas; Koch, Manuel; Eckes, Beate

    2012-06-29

    The tensile and scaffolding properties of skin rely on the complex extracellular matrix (ECM) that surrounds cells, vasculature, nerves, and adnexus structures and supports the epidermis. In the skin, collagen I fibrils are the major structural component of the dermal ECM, decorated by proteoglycans and by fibril-associated collagens with interrupted triple helices such as collagens XII and XIV. Here we show that the cartilage oligomeric matrix protein (COMP), an abundant component of cartilage ECM, is expressed in healthy human skin. COMP expression is detected in the dermal compartment of skin and in cultured fibroblasts, whereas epidermis and HaCaT cells are negative. In addition to binding collagen I, COMP binds to collagens XII and XIV via their C-terminal collagenous domains. All three proteins codistribute in a characteristic narrow zone in the superficial papillary dermis of healthy human skin. Ultrastructural analysis by immunogold labeling confirmed colocalization and further revealed the presence of COMP along with collagens XII and XIV in anchoring plaques. On the basis of these observations, we postulate that COMP functions as an adapter protein in human skin, similar to its function in cartilage ECM, by organizing collagen I fibrils into a suprastructure, mainly in the vicinity of anchoring plaques that stabilize the cohesion between the upper dermis and the basement membrane zone.

  9. Mechanical adaptability of the Bouligand-type structure in natural dermal armour

    NASA Astrophysics Data System (ADS)

    Zimmermann, Elizabeth A.; Gludovatz, Bernd; Schaible, Eric; Dave, Neil K. N.; Yang, Wen; Meyers, Marc A.; Ritchie, Robert O.

    2013-10-01

    Arapaima gigas, a fresh water fish found in the Amazon Basin, resist predation by piranhas through the strength and toughness of their scales, which act as natural dermal armour. Arapaima scales consist of a hard, mineralized outer shell surrounding a more ductile core. This core region is composed of aligned mineralized collagen fibrils arranged in distinct lamellae. Here we show how the Bouligand-type (twisted plywood) arrangement of collagen fibril lamellae has a key role in developing their unique protective properties, by using in situ synchrotron small-angle X-ray scattering during mechanical tensile tests to observe deformation mechanisms in the fibrils. Specifically, the Bouligand-type structure allows the lamellae to reorient in response to the loading environment; remarkably, most lamellae reorient towards the tensile axis and deform in tension through stretching/sliding mechanisms, whereas other lamellae sympathetically rotate away from the tensile axis and compress, thereby enhancing the scale’s ductility and toughness to prevent fracture.

  10. Surface modification of implants in long bone.

    PubMed

    Förster, Yvonne; Rentsch, Claudia; Schneiders, Wolfgang; Bernhardt, Ricardo; Simon, Jan C; Worch, Hartmut; Rammelt, Stefan

    2012-01-01

    Coatings of orthopedic implants are investigated to improve the osteoinductive and osteoconductive properties of the implant surfaces and thus to enhance periimplant bone formation. By applying coatings that mimic the extracellular matrix a favorable environment for osteoblasts, osteoclasts and their progenitor cells is provided to promote early and strong fixation of implants. It is known that the early bone ongrowth increases primary implant fixation and reduces the risk of implant failure. This review presents an overview of coating titanium and hydroxyapatite implants with components of the extracellular matrix like collagen type I, chondroitin sulfate and RGD peptide in different small and large animal models. The influence of these components on cells, the inflammation process, new bone formation and bone/implant contact is summarized.

  11. UV-Induced Triggering of a Biomechanical Initiation Switch Within Collagen Promotes Development of a Melanoma-Permissive Microenvironment in the Skin

    DTIC Science & Technology

    2012-09-01

    human dermal fibroblasts, cell adhesion assays were carried out with collagen type-I that was not irradiated or irradiated with UVA over a dose... dermal fibroblasts to UVA -irradiated MatrigelTM. Given the differential impact of UVB-irradiated MatrigelTM had on cell adhesion, we examined the...or higher as compared to control. In addition, human dermal fibroblast adhesion was enhanced by nearly 40%, at a UVA dose of 5.0J/cm2 (figure 7B

  12. Site-specific rectocele repair with dermal graft augmentation: comparison of porcine dermal xenograft (Pelvicol) and human dermal allograft.

    PubMed

    Biehl, Roger C; Moore, Robert D; Miklos, John R; Kohli, Neeraj; Anand, Indu S; Mattox, T Fleming

    2008-01-01

    This study is a retrospective chart review comparing 195 women who underwent rectocele repair with either a porcine dermal xenograft or human allogenic cadaveric dermal graft augmentation over a two year period. A site-specific defect repair was completed prior to augmentation with the graft. Examinations were performed preoperatively and postoperatively using the pelvic organ prolapse quantification system. Questionnaires were used to assess constipation and dyspareunia. De novo dyspareunia and cure rates for constipation and dyspareunia were not statistically different between the two groups. Site-specific fascial rectocele repairs with xenograft or allograft augmentation were found to have similar complication rates as well as objective and subjective cure rates.

  13. Clinical performance of a dermal filler containing natural glycolic Acid and a polylactic Acid polymer: results of a clinical trial in human immunodeficiency virus subjects with facial lipoatrophy.

    PubMed

    Tagle, Jorge M; Macchetto, Pedro Cervantes; Durán Páramo, Rosa Margarita

    2010-02-01

    Lipoatrophy is a condition that affects certain individuals, most commonly those who are infected with the human immunodeficiency virus.(1-3) Injectable fillers are used for the treatment of these dermal contour deformities to smooth dermal depressions formed by the loss of volume. These dermal fillers (also known as soft tissue augmentation devices) can correct contour deformities caused by lipoatrophy in patients who are human immunodeficiency virus positive or negative. The product used in this study is a patented, second-generation, injectable, dermal collagen stimulator that combines glycolic acid and polylactic acid. The glycolic acid used is not a polymer, but rather an acid derived from sugar cane. Its chemical structure corresponds to that of an alpha-hydroxy acid. Glycolic acid is a well-characterized agent that is present in a number of cosmetic products. Polylactic acid is a synthetic, biocompatible, biodegradable, inert, synthetic polymer from the poly a-hydroxy-acid family that is believed to stimulate fibroblasts to produce more collagen, thus increasing facial volume. Together, polylactic acid and glycolic acid act in concert to 1) stimulate collagen production and 2) hydrate the outer layers of the skin. A multicenter, clinical investigation authorized by the Mexican Secretariat of Health was conducted between September 20, 2002, and September 19, 2004. This clinical study was conducted in male patients between 32 and 60 years of age with lipoatrophy as a result of highly active antiretroviral therapy for human immunodeficiency virus infection. The study objective was to measure the improvement of contour deformities after the injection of a dermal collagen stimulator containing glycolic acid and polylactic acid. In addition to safety, this dermal filler was assessed when used to correct volume deformities caused by lipoatrophy in subjects who are human immunodeficiency virus positive. Thirty male subjects participated and were treated as follows

  14. Estimating terrestrial amphibian pesticide body burden through dermal exposure

    EPA Science Inventory

    Dermal exposure presents a potentially significant but understudied route for pesticide uptake in terrestrial amphibians. Our study measured dermal uptake of pesticides of varying hydrophobicity (logKow) in frogs. Amphibians were indirectly exposed to one of five pesticide active...

  15. Collagen Matrix Remodeling in Stented Pulmonary Arteries after Transapical Heart Valve Replacement.

    PubMed

    Ghazanfari, Samaneh; Driessen-Mol, Anita; Hoerstrup, Simon P; Baaijens, Frank P T; Bouten, Carlijn V C

    2016-01-01

    The use of valved stents for minimally invasive replacement of semilunar heart valves is expected to change the extracellular matrix and mechanical function of the native artery and may thus impair long-term functionality of the implant. Here we investigate the impact of the stent on matrix remodeling of the pulmonary artery in a sheep model, focusing on matrix composition and collagen (re)orientation of the host tissue. Ovine native pulmonary arteries were harvested 8 (n = 2), 16 (n = 4) and 24 (n = 2) weeks after transapical implantation of self-expandable stented heart valves. Second harmonic generation (SHG) microscopy was used to assess the collagen (re)orientation of fresh tissue samples. The collagen and elastin content was quantified using biochemical assays. SHG microscopy revealed regional differences in collagen organization in all explants. In the adventitial layer of the arterial wall far distal to the stent (considered as the control tissue), we observed wavy collagen fibers oriented in the circumferential direction. These circumferential fibers were more straightened in the adventitial layer located behind the stent. On the luminal side of the wall behind the stent, collagen fibers were aligned along the stent struts and randomly oriented between the struts. Immediately distal to the stent, however, fibers on both the luminal and the adventitial side of the wall were oriented in the axial direction, demonstrating the stent impact on the collagen structure of surrounding arterial tissues. Collagen orientation patterns did not change with implantation time, and biochemical analyses showed no changes in the trend of collagen and elastin content with implantation time or location of the vascular wall. We hypothesize that the collagen fibers on the adventitial side of the arterial wall and behind the stent straighten in response to the arterial stretch caused by oversizing of the stent. However, the collagen organization on the luminal side suggests that

  16. Collagen Matrix Remodeling in Stented Pulmonary Arteries after Transapical Heart Valve Replacement

    PubMed Central

    Ghazanfari, Samaneh; Driessen-Mol, Anita; Hoerstrup, Simon P.; Baaijens, Frank P.T.; Bouten, Carlijn V.C.

    2016-01-01

    The use of valved stents for minimally invasive replacement of semilunar heart valves is expected to change the extracellular matrix and mechanical function of the native artery and may thus impair long-term functionality of the implant. Here we investigate the impact of the stent on matrix remodeling of the pulmonary artery in a sheep model, focusing on matrix composition and collagen (re)orientation of the host tissue. Ovine native pulmonary arteries were harvested 8 (n = 2), 16 (n = 4) and 24 (n = 2) weeks after transapical implantation of self-expandable stented heart valves. Second harmonic generation (SHG) microscopy was used to assess the collagen (re)orientation of fresh tissue samples. The collagen and elastin content was quantified using biochemical assays. SHG microscopy revealed regional differences in collagen organization in all explants. In the adventitial layer of the arterial wall far distal to the stent (considered as the control tissue), we observed wavy collagen fibers oriented in the circumferential direction. These circumferential fibers were more straightened in the adventitial layer located behind the stent. On the luminal side of the wall behind the stent, collagen fibers were aligned along the stent struts and randomly oriented between the struts. Immediately distal to the stent, however, fibers on both the luminal and the adventitial side of the wall were oriented in the axial direction, demonstrating the stent impact on the collagen structure of surrounding arterial tissues. Collagen orientation patterns did not change with implantation time, and biochemical analyses showed no changes in the trend of collagen and elastin content with implantation time or location of the vascular wall. We hypothesize that the collagen fibers on the adventitial side of the arterial wall and behind the stent straighten in response to the arterial stretch caused by oversizing of the stent. However, the collagen organization on the luminal side suggests that

  17. Platelet-Rich Fibrin Lysate Can Ameliorate Dysfunction of Chronically UVA-Irradiated Human Dermal Fibroblasts.

    PubMed

    Wirohadidjojo, Yohanes Widodo; Budiyanto, Arief; Soebono, Hardyanto

    2016-09-01

    To determine whether platelet-rich fibrin lysate (PRF-L) could restore the function of chronically ultraviolet-A (UVA)-irradiated human dermal fibroblasts (HDFs), we isolated and sub-cultured HDFs from six different human foreskins. HDFs were divided into two groups: those that received chronic UVA irradiation (total dosages of 10 J cm⁻²) and those that were not irradiated. We compared the proliferation rates, collagen deposition, and migration rates between the groups and between chronically UVA-irradiated HDFs in control and PRF-L-treated media. Our experiment showed that chronic UVA irradiation significantly decreased (p<0.05) the proliferation rates, migration rates, and collagen deposition of HDFs, compared to controls. Compared to control media, chronically UVA-irradiated HDFs in 50% PRF-L had significantly increased proliferation rates, migration rates, and collagen deposition (p<0.05), and the migration rates and collagen deposition of chronically UVA-irradiated HDFs in 50% PRF-L were equal to those of normal fibroblasts. Based on this experiment, we concluded that PRF-L is a good candidate material for treating UVA-induced photoaging of skin, although the best method for its clinical application remains to be determined.

  18. Platelet-Rich Fibrin Lysate Can Ameliorate Dysfunction of Chronically UVA-Irradiated Human Dermal Fibroblasts

    PubMed Central

    Budiyanto, Arief; Soebono, Hardyanto

    2016-01-01

    To determine whether platelet-rich fibrin lysate (PRF-L) could restore the function of chronically ultraviolet-A (UVA)-irradiated human dermal fibroblasts (HDFs), we isolated and sub-cultured HDFs from six different human foreskins. HDFs were divided into two groups: those that received chronic UVA irradiation (total dosages of 10 J cm-2) and those that were not irradiated. We compared the proliferation rates, collagen deposition, and migration rates between the groups and between chronically UVA-irradiated HDFs in control and PRF-L-treated media. Our experiment showed that chronic UVA irradiation significantly decreased (p<0.05) the proliferation rates, migration rates, and collagen deposition of HDFs, compared to controls. Compared to control media, chronically UVA-irradiated HDFs in 50% PRF-L had significantly increased proliferation rates, migration rates, and collagen deposition (p<0.05), and the migration rates and collagen deposition of chronically UVA-irradiated HDFs in 50% PRF-L were equal to those of normal fibroblasts. Based on this experiment, we concluded that PRF-L is a good candidate material for treating UVA-induced photoaging of skin, although the best method for its clinical application remains to be determined. PMID:27401663

  19. Relationship between canine visceral leishmaniosis and the Leishmania (Leishmania) chagasi burden in dermal inflammatory foci.

    PubMed

    Giunchetti, R C; Mayrink, W; Genaro, O; Carneiro, C M; Corrêa-Oliveira, R; Martins-Filho, O A; Marques, M J; Tafuri, W L; Reis, A B

    2006-01-01

    The skin is the first point of contact with organisms of the genus Leishmania from sand fly vectors, and apparently normal skin of sick dogs harbours amastigote forms of Leishmania chagasi. In relation to canine visceral leishmaniosis (CVL), the ear skin was examined in 10 uninfected dogs (UDs) and in 31 dogs dogs naturally infected with L. chagasi. The infected animals consisted of 10 symptomless dogs (SLDs), 12 mildly affected dogs (MADs) and nine affected dogs (ADs). A higher parasite burden was demonstrated in ADs than in SLDs by anti-Leishmania immunohistochemistry (P<0.01), and by Leishman Donivan Unit (LDU) indices (P=0.0024) obtained from Giemsa-stained impression smears. Sections stained with haematoxylin and eosin demonstrated a higher intensity of inflammatory changes in ADs than in SLDs (P<0.05), and in the latter group flow cytometry demonstrated a correlation (P=0.05/r=0.7454) between the percentage of CD14(+) monocytes in peripheral blood and chronic dermal inflammation. Extracellular matrix assessment for reticular fibres by staining of sections with Masson trichrome and Gomori ammoniacal silver demonstrated a decrease in collagen type I and an increase in collagen type III as the clinical signs increased. The data on correlation between cellular phenotypes and histological changes seemed to reflect cellular activation and migration from peripheral blood to the skin, mediated by antigenic stimulation. The results suggested that chronic dermal inflammation and cutaneous parasitism were directly related to the severity of clinical disease.

  20. Irradiated PVAl membrane swelled with chitosan solution as dermal equivalent

    NASA Astrophysics Data System (ADS)

    Rodas, A. C. D.; Ohnuki, T.; Mathor, M. B.; Lugao, A. B.

    2005-07-01

    Synthetic membranes as dermal equivalent can be applied at in vitro studies for developing new transdermal drugs or cosmetics. These membranes could be composed to mimic the dermis and seed cultivated keratinocytes as epidermal layer on it. The endothelial cells ingrowth to promote neovascularization and fibroblasts ingrowth to promote the substitution of this scaffold by natural components of the dermis. As, they can mimic the scaffold function of dermis; the membranes with biological interaction could be used for in vivo studies as dermal equivalent. For this application, poly(vinyl alcohol) (PVAl) membranes crosslinked by gamma radiation were swelled with chitosan solution. PVAl do not interact with the organism when implanted and is intended to mimic the mechanical characteristics of the dermal scaffold. The chitosan as a biocompatible biosynthetic polysaccharide were incorporated into PVAl membranes to improve the organism response. Degradation of chitosan by the organism occurs preferably by hydrolysis or enzymatic action, for example, by lysozyme. For this purpose the swelling kinetic of PVAl membranes with chitosan solution were performed and it was verified their degradation in vitro. The results showed that the swelling equilibrium of the PVAl membranes with chitosan membranes was reached in 120 h with average swelling of 1730%. After swelling, PVAl and chitosan/PVAl membranes were dried and immersed in phosphate buffer solution pH 5.7 and pH 7.4, with and without lysozyme, as those pH values are the specific physiologic pH for external skin and the general physiological pH for the organism, respectively. It was verified that the pure PVAl membrane did not showed change in their mass during 14 days. PVAl membranes swelled with chitosan solution showed mass decrease from 1 to 14 days inside these solutions. The highest mass decrease was verified at pH 5.7 in phosphate buffer solution without lysozyme. The smallest mass decrease was verified at pH 7.4 in

  1. Potential dermal wound healing agent in Blechnum orientale Linn

    PubMed Central

    2011-01-01

    Background Blechnum orientale Linn. (Blechnaceae) is used ethnomedicinally to treat wounds, boils, blisters or abscesses and sores, stomach pain and urinary bladder complaints. The aim of the study was to validate the ethnotherapeutic claim and to evaluate the effects of B. orientale water extract on wound healing activity. Methods Water extract of B. orientale was used. Excision wound healing activity was examined on Sprague-Dawley rats, dressed with 1% and 2% of the water extract. Control groups were dressed with the base cream (vehicle group, negative control) and 10% povidone-iodine (positive control) respectively. Healing was assessed based on contraction of wound size, mean epithelisation time, hydroxyproline content and histopathological examinations. Statistical analyses were performed using one way ANOVA followed by Tukey HSD test. Results Wound healing study revealed significant reduction in wound size and mean epithelisation time, and higher collagen synthesis in the 2% extract-treated group compared to the vehicle group. These findings were supported by histolopathological examinations of healed wound sections which showed greater tissue regeneration, more fibroblasts and angiogenesis in the 2% extract-treated group. Conclusions The ethnotherapeutic use of this fern is validated. The water extract of B. orientale is a potential candidate for the treatment of dermal wounds. Synergistic effects of both strong antioxidant and antibacterial activities in the extract are deduced to have accelerated the wound repair at the proliferative phase of the healing process. PMID:21835039

  2. Sunscreens promote repair of ultraviolet radiation-induced dermal damage.

    PubMed

    Kligman, L H; Akin, F J; Kligman, A M

    1983-08-01

    Chronic UV irradiation profoundly damages the dermis of human and animal skin. These alterations were thought to be irreversible. Recently, we showed that substantial repair occurred in hairless mice after stopping UV exposure. A band of new connective tissue was laid down subepidermally. The present study focussed on whether repair would occur if animals were protected by sunscreens after dermal damage was induced and irradiation was continued. Albino hairless mice were exposed to Westinghouse FS20 sunlamps thrice weekly for 30 weeks. The daily dose of UV (UVB + UVA) was 0.17 J/cm2. Sunscreens of sun protection factors (SPF) 6 and 15 were applied after 10 and 20 weeks of irradiation. Biopsies were taken at 10, 20, 30, and 45 weeks of the experiment. With both sunscreens, especially SPF-15, previously damaged dermis was repaired during continued irradiation. Repair occurred in situ and, in severely damaged skin, in the novel form of subepidermal reconstruction zones of new connective tissue with parallel collagen bundles and a network of fine elastic fibers.

  3. LINKING DERMAL MODELING AND LOADING DATA TO PREDICT LONG-TERM DOSES FROM INTERMITTENT DERMAL CONTACT

    EPA Science Inventory

    In this paper we assess dermal exposure and dose resulting from intermittent contact with residue-contaminated surfaces. These estimates require an understanding of (1) the quantitative relationship between exposure and absorbed dose; (2) the impact of intermittent exposure on ...

  4. Correlative nonlinear optical microscopy and infrared nanoscopy reveals collagen degradation in altered parchments.

    PubMed

    Latour, Gaël; Robinet, Laurianne; Dazzi, Alexandre; Portier, François; Deniset-Besseau, Ariane; Schanne-Klein, Marie-Claire

    2016-05-19

    This paper presents the correlative imaging of collagen denaturation by nonlinear optical microscopy (NLO) and nanoscale infrared (IR) spectroscopy to obtain morphological and chemical information at different length scales. Such multiscale correlated measurements are applied to the investigation of ancient parchments, which are mainly composed of dermal fibrillar collagen. The main issue is to characterize gelatinization, the ultimate and irreversible alteration corresponding to collagen denaturation to gelatin, which may also occur in biological tissues. Key information about collagen and gelatin signatures is obtained in parchments and assessed by characterizing the denaturation of pure collagen reference samples. A new absorbing band is observed near the amide I band in the IR spectra, correlated to the onset of fluorescence signals in NLO images. Meanwhile, a strong decrease is observed in Second Harmonic signals, which are a structural probe of the fibrillar organization of the collagen at the micrometer scale. NLO microscopy therefore appears as a powerful tool to reveal collagen degradation in a non-invasive way. It should provide a relevant method to assess or monitor the condition of collagen-based materials in museum and archival collections and opens avenues for a broad range of applications regarding this widespread biological material.

  5. Correlative nonlinear optical microscopy and infrared nanoscopy reveals collagen degradation in altered parchments

    NASA Astrophysics Data System (ADS)

    Latour, Gaël; Robinet, Laurianne; Dazzi, Alexandre; Portier, François; Deniset-Besseau, Ariane; Schanne-Klein, Marie-Claire

    2016-05-01

    This paper presents the correlative imaging of collagen denaturation by nonlinear optical microscopy (NLO) and nanoscale infrared (IR) spectroscopy to obtain morphological and chemical information at different length scales. Such multiscale correlated measurements are applied to the investigation of ancient parchments, which are mainly composed of dermal fibrillar collagen. The main issue is to characterize gelatinization, the ultimate and irreversible alteration corresponding to collagen denaturation to gelatin, which may also occur in biological tissues. Key information about collagen and gelatin signatures is obtained in parchments and assessed by characterizing the denaturation of pure collagen reference samples. A new absorbing band is observed near the amide I band in the IR spectra, correlated to the onset of fluorescence signals in NLO images. Meanwhile, a strong decrease is observed in Second Harmonic signals, which are a structural probe of the fibrillar organization of the collagen at the micrometer scale. NLO microscopy therefore appears as a powerful tool to reveal collagen degradation in a non-invasive way. It should provide a relevant method to assess or monitor the condition of collagen-based materials in museum and archival collections and opens avenues for a broad range of applications regarding this widespread biological material.

  6. Correlative nonlinear optical microscopy and infrared nanoscopy reveals collagen degradation in altered parchments

    PubMed Central

    Latour, Gaël; Robinet, Laurianne; Dazzi, Alexandre; Portier, François; Deniset-Besseau, Ariane; Schanne-Klein, Marie-Claire

    2016-01-01

    This paper presents the correlative imaging of collagen denaturation by nonlinear optical microscopy (NLO) and nanoscale infrared (IR) spectroscopy to obtain morphological and chemical information at different length scales. Such multiscale correlated measurements are applied to the investigation of ancient parchments, which are mainly composed of dermal fibrillar collagen. The main issue is to characterize gelatinization, the ultimate and irreversible alteration corresponding to collagen denaturation to gelatin, which may also occur in biological tissues. Key information about collagen and gelatin signatures is obtained in parchments and assessed by characterizing the denaturation of pure collagen reference samples. A new absorbing band is observed near the amide I band in the IR spectra, correlated to the onset of fluorescence signals in NLO images. Meanwhile, a strong decrease is observed in Second Harmonic signals, which are a structural probe of the fibrillar organization of the collagen at the micrometer scale. NLO microscopy therefore appears as a powerful tool to reveal collagen degradation in a non-invasive way. It should provide a relevant method to assess or monitor the condition of collagen-based materials in museum and archival collections and opens avenues for a broad range of applications regarding this widespread biological material. PMID:27194180

  7. 40 CFR 798.2250 - Dermal toxicity.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... clinical abnormalities, gross lesions, identified target organs, body weight changes, effect on mortality... (CONTINUED) HEALTH EFFECTS TESTING GUIDELINES Subchronic Exposure § 798.2250 Dermal toxicity. (a) Purpose. In...-observed-effect level and toxic effects associated with continuous or repeated exposure to a test...

  8. 40 CFR 798.2250 - Dermal toxicity.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... clinical abnormalities, gross lesions, identified target organs, body weight changes, effect on mortality... (CONTINUED) HEALTH EFFECTS TESTING GUIDELINES Subchronic Exposure § 798.2250 Dermal toxicity. (a) Purpose. In...-observed-effect level and toxic effects associated with continuous or repeated exposure to a test...

  9. A Dermal Piercing Complicated by Mycobacterium fortuitum.

    PubMed

    Patel, Trisha; Scroggins-Markle, Leslie; Kelly, Brent

    2013-01-01

    Background. Dermal piercings have recently become a fashion symbol. Common complications include hypertrophic scarring, rejection, local infection, contact allergy, and traumatic tearing. We report a rare case of Mycobacterium fortuitum following a dermal piercing and discuss its medical implications and treatments. Case. A previously healthy 19-year-old woman presented complaining of erythema and edema at the site of a dermal piercing on the right fourth dorsal finger. She was treated with a 10-day course of trimethoprim-sulfamethoxazole and one course of cephalexin by her primary care physician with incomplete resolution. The patient stated that she had been swimming at a local water park daily. A punch biopsy around the dermal stud was performed, and cultures with sensitivities revealed Mycobacterium fortuitum. The patient was treated with clarithromycin and ciprofloxacin for two months receiving full resolution. Discussion. Mycobacterium fortuitum is an infrequent human pathogen. This organism is a Runyon group IV, rapidly growing nontuberculous mycobacteria, often found in water,soil, and dust. Treatment options vary due to the size of the lesion. Small lesions are typically excised, while larger lesions require treatment for 2-6 months with antibiotics. We recommend a high level of suspicion for atypical mycobacterial infections in a piercing resistant to other therapies.

  10. Collagen/chitosan porous scaffolds with improved biostability for skin tissue engineering.

    PubMed

    Ma, Lie; Gao, Changyou; Mao, Zhengwei; Zhou, Jie; Shen, Jiacong; Hu, Xueqing; Han, Chunmao

    2003-11-01

    Porous scaffolds for skin tissue engineering were fabricated by freeze-drying the mixture of collagen and chitosan solutions. Glutaraldehyde (GA) was used to treat the scaffolds to improve their biostability. Confocal laser scanning microscopy observation confirmed the even distribution of these two constituent materials in the scaffold. The GA concentrations have a slight effect on the cross-section morphology and the swelling ratios of the cross-linked scaffolds. The collagenase digestion test proved that the presence of chitosan can obviously improve the biostability of the collagen/chitosan scaffold under the GA treatment, where chitosan might function as a cross-linking bridge. A detail investigation found that a steady increase of the biostability of the collagen/chitosan scaffold was achieved when GA concentration was lower than 0.1%, then was less influenced at a still higher GA concentration up to 0.25%. In vitro culture of human dermal fibroblasts proved that the GA-treated scaffold could retain the original good cytocompatibility of collagen to effectively accelerate cell infiltration and proliferation. In vivo animal tests further revealed that the scaffold could sufficiently support and accelerate the fibroblasts infiltration from the surrounding tissue. Immunohistochemistry analysis of the scaffold embedded for 28 days indicated that the biodegradation of the 0.25% GA-treated scaffold is a long-term process. All these results suggest that collagen/chitosan scaffold cross-linked by GA is a potential candidate for dermal equivalent with enhanced biostability and good biocompatibility.

  11. Collagen cross-linking in sun-exposed and unexposed sites of aged human skin

    NASA Technical Reports Server (NTRS)

    Yamauchi, M.; Prisayanh, P.; Haque, Z.; Woodley, D. T.

    1991-01-01

    A recently described nonreducible, acid-heat stable compound, histidinohydroxylysinonorleucine (HHL), is a collagen cross-link isolated from mature skin tissue. Its abundance is related to chronologic aging of skin. The present communication describes the quantity of HHL from aged human skin of the same individuals in sun-exposed (wrist) and unexposed (buttock) sites. Punch biopsies were obtained from these sites from nine people of age 60 or older. HHL contents (moles/mole of collagen) at these sites were for wrist 0.13 +/- 0.07 and for buttock 0.69 +/- 0.17 (mean +/- SD, p less than 0.001). In addition, it was found that acute irradiation of the cross-linked peptides with UVA (up to 250 J/cm2) and UVB (up to 1 J/cm2) had no effect on HHL structure. The same treatment significantly degraded another nonreducible, stable collagen cross-link, pyridinoline. The results suggest that chronic sunlight exposure may be associated with an impediment to normal maturation of human dermal collagen resulting in tenuous amount of HHL. Thus, the process of photoaging in dermal collagen is different from that of chronologic aging in human skin.

  12. EBI3 Downregulation Contributes to Type I Collagen Overexpression in Scleroderma Skin.

    PubMed

    Kudo, Hideo; Wang, Zhongzhi; Jinnin, Masatoshi; Nakayama, Wakana; Inoue, Kuniko; Honda, Noritoshi; Nakashima, Taiji; Kajihara, Ikko; Makino, Katsunari; Makino, Takamitsu; Fukushima, Satoshi; Ihn, Hironobu

    2015-10-15

    IL-12 family cytokines are implicated in the pathogenesis of various autoimmune diseases, but their role in the regulation of extracellular matrix expression and its contribution to the phenotype of systemic sclerosis (SSc) remain to be elucidated. Among the IL-12 family members, IL-35 decreases type I collagen expression in cultured dermal fibroblasts. IL-35 consists of p35 and EBI3 subunits, and EBI3 alone could downregulate the protein and mRNA expression of type I or type III collagen in the presence or absence of TGF-β costimulation. We found that collagen mRNA stability was reduced by EBI3 via the induction of miR-4500. The IL-35 levels in the sera or on the surface of T cells were not altered in SSc patients, while EBI3 expression was decreased in the keratinocytes of the epidermis and regulatory T cells of the dermis in SSc skin compared with normal skin, which may induce collagen synthesis in SSc dermal fibroblasts. We also found that gp130, the EBI3 receptor, was expressed in both normal and SSc fibroblasts. Moreover, we revealed that EBI3 supplementation by injection into the skin improves mice skin fibrosis. Decreased EBI3 in SSc skin may contribute to an increase in collagen accumulation and skin fibrosis. Clarifying the mechanism regulating the extracellular matrix expression by EBI3 in SSc skin may lead to better understanding of this disease and new therapeutic strategies using ointment or microinjection of the subunit.

  13. Collagen vascular disease

    MedlinePlus

    ... developed these disorders were previously said to have "connective tissue" or "collagen vascular" disease. We now have names ... be used. These include as undifferentiated systemic rheumatic (connective tissue) diseases or overlap syndromes. Images Dermatomyositis, heliotrope eyelids ...

  14. Novel collagen sponge reinforced with polyglycolic acid fiber produces robust, normal hair in murine hair reconstitution model.

    PubMed

    Itoh, M; Hiraoka, Y; Kataoka, K; Huh, N H; Tabata, Y; Okochi, H

    2004-01-01

    The hair reconstitution assay is a useful system for studying cell-cell and epithelial-mesenchymal interaction. The current method consists of transplantation of both epidermal and dermal cells, using a silicone chamber placed on an athymic nude mouse. However, because of leakage and tilting of the grafted cells, the rate and area of hair growth vary depending on the chamber. We modified this method by using a collagen sponge as a scaffold and compared two types of collagen sponges, each having different tensile strengths. A conventional collagen sponge disturbed normal hair follicle formation; in contrast, a collagen sponge containing polyglycolic acid (PGA) fiber supported proper restructuring of skin and hair follicles. These data suggested the usefulness of PGA fiber-containing collagen sponges for hair reconstitution in research and clinical applications.

  15. Nanomechanics of collagen microfibrils

    PubMed Central

    Vesentini, Simone; Redaelli, Alberto; Gautieri, Alfonso

    2013-01-01

    Summary Collagen constitutes one third of the human proteome, providing mechanical stability, elasticity and strength to organisms and is thus the prime construction material in biology. Collagen is also the dominating material in the extracellular matrix where its stiffness controls cell differentiation, growth and pathology. We use atomistic-based hierarchical multiscale modeling to describe this complex biological material from the bottom up. This includes the use and development of large-scale computational modeling tools to investigate several aspects related to collagen-based tissues, including source of visco-elasticity and deformation mechanisms at the nanoscale level. The key innovation of this research is that until now, collagen materials have primarily been described at macroscopic scales, without explicitly understanding the mechanical contributions at the molecular and fibrillar levels. The major impact of this research will be the development of fundamental models of collagenous tissues, important to the design of new scaffolding biomaterials for regenerative medicine as well as for the understanding of collagen-related diseases. PMID:23885342

  16. A Dermal Equivalent Engineered with TGF-β3 Expressing Bone Marrow Stromal Cells and Amniotic Membrane: Cosmetic Healing of Full-Thickness Skin Wounds in Rats.

    PubMed

    Samadikuchaksaraei, Ali; Mehdipour, Ahmad; Habibi Roudkenar, Mehryar; Verdi, Javad; Joghataei, Mohammad Taghi; As'adi, Kamran; Amiri, Fatemeh; Dehghan Harati, Mozhgan; Gholipourmalekabadi, Mazaher; Karkuki Osguei, Nushin

    2016-12-01

    Transforming growth factor beta-3 (TGF-β3) has been shown to decrease scar formation after scheduled topical applications to the cutaneous wounds. This study aimed to continuously deliver TGF-β3, during the early phase of wound healing, by engineering a dermal equivalent (DE) using TGF-β3 expressing bone marrow stromal cells (BM-SCs) and human dehydrated amniotic membrane (hDAM). To engineer a DE, rat BM-SCs were seeded on the hDAM and TGF-β3 was transiently transfected into the BM-SCs using a plasmid vector. Pieces of the dermal equivalent were transplanted onto the full-thickness excisional skin wounds in rats. The process of wound healing was assessed by image analysis, Manchester Scar Scale (MSS), and histopathological studies 7, 14, 21, and 85 days after the excision. The results confirmed accurate construction of recombinant pcDNA3.1-TGF-β3 expression system and showed that the transfected BM-SCs seeded on hDAM expressed TGF-β3 mRNA and protein from day 3 through day 7 after transfection. After implantation of the DE, contraction of the wounds was measured from day 7 through 21 and analyzed by linear regression, which revealed that the rate of wound contraction in all experimental groups was similar. Histologic evaluation demonstrated that transfected BM-SCs decreased retention and recruitment of the cells during the early stage of wound healing, decreased the formation of vascular structures and led to formation of uniformly parallel collagen bundles. MSS scores showed that TGF-β3 secreting cells significantly improved the cosmetic appearance of the healed skin and decreased the scar formation. From these results, it could be concluded that transient secretion of TGF-β3, during the early phase of healing, by BM-SCs seeded on hDAM can improve the cosmetic appearance of the scar in cutaneous wounds without negatively affecting the process of wound repair.

  17. Dental Implants.

    PubMed

    Zohrabian, Vahe M; Sonick, Michael; Hwang, Debby; Abrahams, James J

    2015-10-01

    Dental implants restore function to near normal in partially or completely edentulous patients. A root-form implant is the most frequently used type of dental implant today. The basis for dental implants is osseointegration, in which osteoblasts grow and directly integrate with the surface of titanium posts surgically embedded into the jaw. Radiologic assessment is critical in the preoperative evaluation of the dental implant patient, as the exact height, width, and contour of the alveolar ridge must be determined. Moreover, the precise locations of the maxillary sinuses and mandibular canals, as well as their relationships to the site of implant surgery must be ascertained. As such, radiologists must be familiar with implant design and surgical placement, as well as augmentation procedures utilized in those patients with insufficient bone in the maxilla and mandible to support dental implants.

  18. Cochlear Implants

    MedlinePlus

    ... NIDCD A cochlear implant is a small, complex electronic device that can help to provide a sense ... are better able to hear, comprehend sound and music, and speak than their peers who receive implants ...

  19. Cochlear implant

    MedlinePlus

    ... antenna. This part of the implant receives the sound, converts the sound into an electrical signal, and sends it to ... implants allow deaf people to receive and process sounds and speech. However, these devices do not restore ...

  20. Stability of collagen in the presence of 3,4-dihydroxyphenylalanine (DOPA).

    PubMed

    Usha, R; Rajaram, A; Ramasami, T

    2009-10-06

    Many cross-linking agents for collagen are available with varying levels of toxicity and some are in use in biomedical implants of collagen. L-DOPA (3,4-dihydroxyphenylalanine), a neurotransmitter, is a naturally present compound in the living system and is the target in therapeutic strategy of Parkinson's disease. This work reports the effect of the neurotransmitter DOPA on the stability of collagen solution using circular dichroism (CD), fluorescence spectroscopy, melting and shrinkage temperature. Collagen solution treated with various concentrations of DOPA ranging from 10(-2) to 10(-5)M was analyzed using fluorescence and CD spectra. When collagen was treated with DOPA, the intensity of emission was found to increase indicating the possibility of interaction of DOPA with collagen and maximum emission intensity was observed between 10(-3) and 10(-4)M for L-DOPA and DL-DOPA, respectively. CD studies show possible aggregation of collagen even in the presence of low concentrations of DOPA. The shrinkage temperature of DOPA treated collagen fibres was experimentally determined to be 69+/-1 degrees C. The melting temperature of DOPA cross linked collagen solution also exhibited a significant increase from 35 to 40 degrees C (+/-0.1) (P<0.05). The experimental results suggest that the optimum concentration for cross linking collagen with DOPA ranges between 10(-3) and 10(-4)M. Thus, DOPA may be a useful stabilizing agent for collagen for biomedical applications.

  1. Collagen bioengineered systems: in situ advanced optical spatiotemporal analysis

    NASA Astrophysics Data System (ADS)

    Hwang, Yu Jer; Lang, Xuye; Granelli, Joseph; Turgman, Cassandra C.; Gigante, Jackie; Lyubovitsky, Julia G.

    2014-05-01

    The architecture of collagen is important in maintenance and regeneration of higher vertebrates' tissues. We had been studying the changes to this architecture with in situ multi-photon optical microscopy that combines nonlinear optical phenomena of second harmonic generation (SHG) and two-photon fluorescence (TPF) signals from collagen hydrogels prepared from different collagen solid content, polymerized at different temperatures, with different ions as well as modified with reducing sugars. We incubated 2 g/l collagen hydrogels with 0.1 M fructose at 37 °C and after about 20 days observed a significant induction of in situ fluorescence. The twophoton fluorescence emission was centered at about 460 nm for 730 nm excitation wavelength and shifted to 480 nm when we changed the excitation wavelength to 790 nm. The one-photon fluorescence emission was centered at about 416 nm when excitation was 330 nm. It red shifted and split into two peaks centered at about 430 nm and 460 nm for 370 nm excitation; 460 nm peak became predominant for 385 nm excitation and further shifted to 470 nm for 390 nm excitation. SHG and TPF imaging showed restructuring of hydrogels upon this modification. We will discuss these findings within the context of our ongoing dermal wound repair research.

  2. Type IV collagen is a novel DEJ biomarker that is reduced by radiotherapy.

    PubMed

    McGuire, J D; Gorski, J P; Dusevich, V; Wang, Y; Walker, M P

    2014-10-01

    The dental basement membrane (BM) is composed of collagen types IV, VI, VII, and XVII, fibronectin, and laminin and plays an inductive role in epithelial-mesenchymal interactions during tooth development. The BM is degraded and removed during later-stage tooth morphogenesis; however, its original position defines the location of the dentin-enamel junction (DEJ) in mature teeth. We recently demonstrated that type VII collagen is a novel component of the inner enamel organic matrix layer contiguous with the DEJ. Since it is frequently co-expressed with and forms functional complexes with type VII collagen, we hypothesized that type IV collagen should also be localized to the DEJ in mature human teeth. To identify collagen IV, we first evaluated defect-free erupted teeth from various donors. To investigate a possible stabilizing role, we also evaluated extracted teeth exposed to high-dose radiotherapy--teeth that manifest post-radiotherapy DEJ instability. We now show that type IV collagen is a component within the morphological DEJ of posterior and anterior teeth from individuals aged 18 to 80 yr. Confocal microscopy revealed that immunostained type IV collagen was restricted to the 5- to 10-µm-wide optical DEJ, while collagenase treatment or previous in vivo tooth-level exposure to > 60 Gray irradiation severely reduced immunoreactivity. This assignment was confirmed by Western blotting with whole-tooth crown and enamel extracts. Without reduction, type IV collagen contained macromolecular α-chains of 225 and 250 kDa. Compositionally, our results identify type IV collagen as the first macromolecular biomarker of the morphological DEJ of mature teeth. Given its network structure and propensity to stabilize the dermal-epidermal junction, we propose that a collagen-IV-enriched DEJ may, in part, explain its well-known fracture toughness, crack propagation resistance, and stability. In contrast, loss of type IV collagen may represent a biochemical rationale for the DEJ

  3. Type IV Collagen is a Novel DEJ Biomarker that is Reduced by Radiotherapy

    PubMed Central

    McGuire, J.D.; Gorski, J.P.; Dusevich, V.; Wang, Y.; Walker, M.P.

    2014-01-01

    The dental basement membrane (BM) is composed of collagen types IV, VI, VII, and XVII, fibronectin, and laminin and plays an inductive role in epithelial-mesenchymal interactions during tooth development. The BM is degraded and removed during later-stage tooth morphogenesis; however, its original position defines the location of the dentin-enamel junction (DEJ) in mature teeth. We recently demonstrated that type VII collagen is a novel component of the inner enamel organic matrix layer contiguous with the DEJ. Since it is frequently co-expressed with and forms functional complexes with type VII collagen, we hypothesized that type IV collagen should also be localized to the DEJ in mature human teeth. To identify collagen IV, we first evaluated defect-free erupted teeth from various donors. To investigate a possible stabilizing role, we also evaluated extracted teeth exposed to high-dose radiotherapy – teeth that manifest post-radiotherapy DEJ instability. We now show that type IV collagen is a component within the morphological DEJ of posterior and anterior teeth from individuals aged 18 to 80 yr. Confocal microscopy revealed that immunostained type IV collagen was restricted to the 5- to 10-µm-wide optical DEJ, while collagenase treatment or previous in vivo tooth-level exposure to > 60 Gray irradiation severely reduced immunoreactivity. This assignment was confirmed by Western blotting with whole-tooth crown and enamel extracts. Without reduction, type IV collagen contained macromolecular α-chains of 225 and 250 kDa. Compositionally, our results identify type IV collagen as the first macromolecular biomarker of the morphological DEJ of mature teeth. Given its network structure and propensity to stabilize the dermal-epidermal junction, we propose that a collagen-IV-enriched DEJ may, in part, explain its well-known fracture toughness, crack propagation resistance, and stability. In contrast, loss of type IV collagen may represent a biochemical rationale for the

  4. Fibronectin functional domains coupled to hyaluronan stimulate adult human dermal fibroblast responses critical for wound healing.

    PubMed

    Ghosh, Kaustabh; Ren, Xiang-Dong; Shu, Xiao Zheng; Prestwich, Glenn D; Clark, Richard A F

    2006-03-01

    Fibronectin (FN) facilitates dermal fibroblast migration during normal wound healing. Proteolytic degradation of FN in chronic wounds hampers healing. Previously, three FN functional domains (FNfd) have been shown to be sufficient for optimal adult human dermal fibroblast migration. Here we report the development of an acellular hydrogel matrix comprised of the FNfds coupled to a hyaluronan (HA) backbone to stimulate wound repair. Employing Michael-type addition, the cysteine- tagged FNfds were first coupled to a homobifunctional PEG derivative. Thereafter, these PEG derivative FNfd solutions, containing bifunctional PEG-derivative crosslinker were coupled to thiol-modified HA (HA-DTPH) to obtain a crosslinked hydrogel matrix. When evaluated in vitro, these acellular hydrogels were completely cytocompatible. While spreading and proliferation of adult human dermal fibroblasts plateaued at higher FNfd bulk densities, their rapid and robust migration followed a typical bell-shaped response. When implanted in porcine cutaneous wounds, these acellular matrices, besides being completely biocompatible, induced rapid and en masse recruitment of stromal fibroblasts that was not observed with RGD-tethered or unmodified hydrogels. Such constructs might be of great benefit in clinical settings where rapid formation of new tissue is needed.

  5. Human dermal stem/progenitor cell-derived conditioned medium ameliorates ultraviolet a-induced damage of normal human dermal fibroblasts.

    PubMed

    Shim, Joong Hyun; Park, Ju-Yearl; Lee, Mi-Gi; Kang, Hak Hee; Lee, Tae Ryong; Shin, Dong Wook

    2013-01-01

    Adult skin stem cells are considered an attractive cell resource for therapeutic potential in aged skin. We previously reported that multipotent human dermal stem/progenitor cells (hDSPCs) can be enriched from (normal human dermal fibroblasts (NHDFs) using collagen type IV. However, the beneficial effects of hDSPCs on aged skin remain to be elucidated. In the present study, we analyzed the growth factors secreted from hDSPCs in conditioned medium (CM) derived from hDSPCs (hDSPC-CM) and found that hDSPCs secreted higher levels of bFGF, IGFBP-1, IGFBP-2, HGF, VEGF and IGF-1 compared with non-hDSPCs. We then investigated whether hDSPC-CM has an effect on ultraviolet A (UVA)-irradiated NHDFs. Real-time RT-PCR analysis revealed that the treatment of UVA-irradiated NHDFs with hDSPC-CM significantly antagonized the UVA-induced up-regulation of the MMP1 and the UVA-induced down-regulation of the collagen types I, IV and V and TIMP1 mRNA expressions. Furthermore, a scratch wound healing assay showed that hDSPC-CM enhanced the migratory properties of UVA-irradiated NHDFs. hDSPC-CM also significantly reduced the number of the early and late apoptotic cell population in UVA-irradiated NHDFs. Taken together, these data suggest that hDSPC-CM can exert some beneficial effects on aged skin and may be used as a therapeutic agent to improve skin regeneration and wound healing.

  6. Improving Large Cetacean Implantable Satellite Tag Designs to Maximize Tag Robustness and Minimize Health Effects to Individual Animals

    DTIC Science & Technology

    2013-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Improving Large Cetacean Implantable Satellite Tag...integrity of designs created in Objective (1) during laboratory experiments and in cetacean carcasses; (3) Examine structural tissue damage in the...blubber, sub-dermal sheath and muscle caused by penetrating dummy implantable tags in cetacean carcasses, including manipulation to simulate live motion

  7. Development of multifunctional collagen scaffolds directed by collagen mimetic peptides

    NASA Astrophysics Data System (ADS)

    Wang, Yi-Lan (Allen)

    Collagen is widely used for soft tissue replacement and tissue engineering scaffold. Functionalized collagen may offer new and improved applications for collagen-based biomaterials. But passively adsorbed molecules readily diffuse out from collagen matrix, and conventional chemical reactions on collagen are difficult to control and may compromise the biochemical feature of natural collagen. Hence, the aim of this dissertation is to develop a new physical collagen modification method through the non-covalent immobilization of collagen mimetic peptides (CMPs) and CMP derivatives on collagen scaffolds, thereby evading the drawbacks of passive and chemical modifications. Most of the research on CMPs over the past three decades has focused on synthesizing CMPs and understanding the effects of amino acid sequence on the peptide structural stability. Although few attempts have been made to develop biomaterials based on pure CMP, CMP has never used in complex with natural collagen. We demonstrate that CMPs with varying chain lengths have strong propensity to associate with natural 2-D and 3-D collagen substrates. We also show that CMPs can recognize and bind to reconstituted type I collagen fibers as well as collagens of ex vivo human liver tissue. The practical use of CMPs conjugated with linear and multi-arm poly(ethylene glycol)s allows to control cell organization in 2-D collagen substrates. Our cell adhesion studies suggest that under certain conditions (e.g. high incubation temperature, small CMP size), the bound CMP derivatives can be released from the collagen matrix, which may provide new opportunities for manipulating cell behavior especially by dynamically controlling the amount of signaling molecules in the collagen matrix. Polyanionic charged CMP was synthesized to modulate tubulogenesis of endothelial cells by attracting VEGF with 3-D collagen gel and a new PEG hydrogel using bifunctional CMP conjugates was synthesized as physico-chemical crosslinkers for

  8. Hydroxyapatite reinforced collagen scaffolds with improved architecture and mechanical properties.

    PubMed

    Kane, Robert J; Weiss-Bilka, Holly E; Meagher, Matthew J; Liu, Yongxing; Gargac, Joshua A; Niebur, Glen L; Wagner, Diane R; Roeder, Ryan K

    2015-04-01

    Hydroxyapatite (HA) reinforced collagen scaffolds have shown promise for synthetic bone graft substitutes and tissue engineering scaffolds. Freeze-dried HA-collagen scaffolds are readily fabricated and have exhibited osteogenicity in vivo, but are limited by an inherent scaffold architecture that results in a relatively small pore size and weak mechanical properties. In order to overcome these limitations, HA-collagen scaffolds were prepared by compression molding HA reinforcements and paraffin microspheres within a suspension of concentrated collagen fibrils (∼ 180 mg/mL), cross-linking the collagen matrix, and leaching the paraffin porogen. HA-collagen scaffolds exhibited an architecture with high porosity (85-90%), interconnected pores ∼ 300-400 μm in size, and struts ∼ 3-100 μm in thickness containing 0-80 vol% HA whisker or powder reinforcements. HA reinforcement enabled a compressive modulus of up to ∼ 1 MPa, which was an order of magnitude greater than unreinforced collagen scaffolds. The compressive modulus was also at least one order of magnitude greater than comparable freeze-dried HA-collagen scaffolds and two orders of magnitude greater than absorbable collagen sponges used clinically. Moreover, scaffolds reinforced with up to 60 vol% HA exhibited fully recoverable elastic deformation upon loading to 50% compressive strain for at least 100,000 cycles. Thus, the scaffold mechanical properties were well-suited for surgical handling, fixation, and bearing osteogenic loads during bone regeneration. The scaffold architecture, permeability, and composition were shown to be conducive to the infiltration and differentiation of adipose-derive stromal cells in vitro. Acellular scaffolds were demonstrated to induce angiogenesis and osteogenesis after subcutaneous ectopic implantation by recruiting endogenous cell populations, suggesting that the scaffolds were osteoinductive.

  9. Mass transfer of large molecules through collagen and collagen-silica hybrid membranes

    NASA Astrophysics Data System (ADS)

    Jofre-Lora, Pedro

    Diabetes is a growing concern in the United States and around the world that must be addressed through new treatment options. Current standard treatment options of diabetes are limiting and have tremendous impacts on patient's lives. Emerging therapies, such as the implantation of encapsulated islets, are promising treatment options, but have not yet materialized due to unsolved problems with material properties. Hybrid silica-collagen membranes address some of these unsolved problems and are a promising material for cell encapsulation. However, the mass transfer properties of large molecules, such as insulin, TNF-alpha, IL1beta, and other important proteins in the etiology of diabetes, through these hybrid membranes are poorly characterized. In order to begin characterizing these properties, a device was constructed to accurately and efficiently measure the mass transfer of other similar large molecules, fluorescein isothiocyanate dextrans (FITC-dextran), through collagen-silica hybrid membranes. The device was used to measure diffusion coefficients of 4, 20, 40, and 150 kDa FITC-dextrans through non-silicified and silicified samples of 200 and 1000 Pa porcine skin collagen. Diffusion coefficients were found to be in the 10-7-10-6 cm2s -1 range, which is in agreement with previously published data for similar molecules through similar hydrogels. The effects of collagen stiffness, FITC-dextran molecular weight, and silicification treatment on diffusion were investigated. It was found that collagen stiffness and FITC-dextran molecular weight had a negative correlation with diffusion, whereas silicification treatment had no global impact on diffusion. The device created, and the results of this preliminary investigation, can be used to develop collagen-silica hybrid membranes as an alternative material for cell encapsulation in a forward-design manner.

  10. Promotion of wound collagen formation in normal and diabetic mice by quadrol.

    PubMed

    Bhide, M V; Dunphy, M J; Mirkopulos, N; Smith, D J

    1988-01-01

    The rate of collagen deposition in implanted polytetrafluoroethylene (PTFE) tubing in non-diabetic and streptozotocin-induced (STZ) diabetic mice was measured during 14 days post-wounding. At the time of implantation, test groups received injections of either Quadrol [N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine], glucan, or buffer in an area adjacent to the wound site. The accumulation of collagen in the implants of Quadrol-treated non-diabetic animals was more than 200% above control on days 8 to 11 and was 50% above control on day 14. In Quadrol-treated STZ-diabetic mice, the collagen accumulation gradually increased from 50% above control on day 8 to 200% above control on day 14. Treatment with glucan increased the collagen accumulation in normal mice 200 to 300% above control from days 8 to 11 respectively and then 30% above control on day 14. Collagen accumulation in the implants of the glucan-treated STZ-diabetic mice was similar to the control group. These results indicate that Quadrol promotes in vivo collagen synthesis and that Quadrol may be effective as a stimulator of wound healing in diabetic and non-diabetic animals.

  11. Repair of Avascular Meniscus Tears with Electrospun Collagen Scaffolds Seeded with Human Cells.

    PubMed

    Baek, Jihye; Sovani, Sujata; Glembotski, Nicholas E; Du, Jiang; Jin, Sungho; Grogan, Shawn P; D'Lima, Darryl D

    2016-03-01

    The self-healing capacity of an injured meniscus is limited to the vascularized regions and is especially challenging in the inner avascular regions. As such, we investigated the use of human meniscus cell-seeded electrospun (ES) collagen type I scaffolds to produce meniscal tissue and explored whether these cell-seeded scaffolds can be implanted to repair defects created in meniscal avascular tissue explants. Human meniscal cells (derived from vascular and avascular meniscal tissue) were seeded on ES scaffolds and cultured. Constructs were evaluated for cell viability, gene expression, and mechanical properties. To determine potential for repair of meniscal defects, human meniscus avascular cells were seeded and cultured on aligned ES collagen scaffolds for 4 weeks before implantation. Surgical defects resembling "longitudinal tears" were created in the avascular zone of bovine meniscus and implanted with cell-seeded collagen scaffolds and cultured for 3 weeks. Tissue regeneration and integration were evaluated by histology, immunohistochemistry, mechanical testing, and magentic resonance imaging. Ex vivo implantation with cell-seeded collagen scaffolds resulted in neotissue that was significantly better integrated with the native tissue than acellular collagen scaffolds or untreated defects. Human meniscal cell-seeded ES collagen scaffolds may therefore be useful in facilitating meniscal repair of avascular meniscus tears.

  12. DERMAL ADIPOCYTES: FROM IRRELEVANCE TO METABOLIC TARGETS?

    PubMed Central

    Kruglikov, Ilja L.; Scherer, Philipp E.

    2015-01-01

    Dermal white adipose tissue (dWAT) has found little appreciation in the past as a distinct entity from the better recognized subcutaneous white adipose tissue (sWAT). However, recent work has established dWAT as an important contributor to a multitude of processes, including immune response, wound healing and scarring, hair follicle growth and thermoregulation. Unique metabolic contributions are attributed to dWAT as well, at least in part due to thermic insulation properties and its response to cold exposure. Dermal adipocytes can also undergo adipocyte-myofibroblast transition (AMT), a process that is suspected to play an important role in a number of pathophysiological processes within the skin. Here, we discuss emerging concepts regarding dWAT physiology and its significance to a variety of cellular processes. PMID:26643658

  13. Optical coherence tomography: imaging architect for dermal microdialysis in psoriasis

    NASA Astrophysics Data System (ADS)

    O'Connell, M.-L.; O'Connor, W.; Ramsay, B.; Guihen, E.; Ho, W. L.; Leahy, M. J.

    2011-03-01

    Optical coherence tomography (OCT) has been used as part of a ground breaking translational study to shed some light on one of the worlds most prevalent autoimmune diseases; psoriasis. The work successfully integrates the fields of optical imaging, biochemistry and dermatology in conducting a dermal microdialysis (DMD) trial for quantitative histamine assessment amongst a group of psoriasis sufferers. The DMD process involves temporary insertion of microscopic hollow tubes into a layer of skin to measure the levels of histamine and other important biological molecules in psoriasis. For comparison purposes, DMD catheters were implanted into healthy, peri-lesional and lesional skin regions. The catheters' entry and exit points and their precise locations in the epidermal layer of the skin were confirmed using OCT thus obtaining high resolution, wide-field images of the affected skin as well as catheter placement whilst local microdialysis enabled a tissue chemistry profile to be obtained from these three skin regions including histamine, a local immune system activator known to contribute towards itch and inflammation. Together these tools offer a synergistic approach in the clinical assessment of the disease. In addition, OCT delivered a non-invasive and rapid method for analyzing the affected skin architecture.

  14. Collagen Fragmentation Promotes Oxidative Stress and Elevates Matrix Metalloproteinase-1 in Fibroblasts in Aged Human Skin

    PubMed Central

    Fisher, Gary J.; Quan, Taihao; Purohit, Trupta; Shao, Yuan; Cho, Moon Kyun; He, Tianyuan; Varani, James; Kang, Sewon; Voorhees, John J.

    2009-01-01

    Aged human skin is fragile because of fragmentation and loss of type I collagen fibrils, which confer strength and resiliency. We report here that dermal fibroblasts express increased levels of collagen-degrading matrix metalloproteinases-1 (MMP-1) in aged (>80 years old) compared with young (21 to 30 years old) human skin in vivo. Transcription factor AP-1 and α2β1 integrin, which are key regulators of MMP-1 expression, are also elevated in fibroblasts in aged human skin in vivo. MMP-1 treatment of young skin in organ culture causes fragmentation of collagen fibrils and reduces fibroblast stretch, consistent with reduced mechanical tension, as observed in aged human skin. Limited fragmentation of three-dimensional collagen lattices with exogenous MMP-1 also reduces fibroblast stretch and mechanical tension. Furthermore, fibroblasts cultured in fragmented collagen lattices express elevated levels of MMP-1, AP-1, and α2β1 integrin. Importantly, culture in fragmented collagen raises intracellular oxidant levels and treatment with antioxidant MitoQ10 significantly reduces MMP-1 expression. These data identify positive feedback regulation that couples age-dependent MMP-1-catalyzed collagen fragmentation and oxidative stress. We propose that this self perpetuating cycle promotes human skin aging. These data extend the current understanding of the oxidative theory of aging beyond a cellular-centric view to include extracellular matrix and the critical role that connective tissue microenvironment plays in the biology of aging. PMID:19116368

  15. Changes of MMP-1 and collagen type Ialpha1 by UVA, UVB and IRA are differentially regulated by Trx-1.

    PubMed

    Buechner, Nicole; Schroeder, Peter; Jakob, Sascha; Kunze, Kerstin; Maresch, Tanja; Calles, Christian; Krutmann, Jean; Haendeler, Judith

    2008-07-01

    Exposure of human skin to solar radiation, which includes ultraviolet (UV) radiation (UVA and UVB) visible light and infrared radiation, induces skin aging. The effects of light have been attributed to irradiation-induced reactive oxygen species (ROS) formation, but the specific signaling pathways are not well understood. Detrimental effects of solar radiation are dermal diseases and photoaging. Exposure of cultured human dermal fibroblasts to UVA, UVB or IRA increased ROS formation in vitro. One important redox regulator is the oxidoreductase thioredoxin-1 (Trx). Trx is ubiquitously expressed and has anti-oxidative and anti-apoptotic properties. Besides its function to reduce H(2)O(2), Trx binds to and regulates transcription factors. The aim of this study was to investigate whether Trx influences the regulation of MMP-1 and collagen Ialpha1 by UVA, UVB and IRA. We irradiated human dermal fibroblasts with UVA, UVB and IRA. UVA, UVB and IRA upregulated MMP-1 expression. Trx inhibited UVA-induced MMP-1 upregulation in a NFkappaB dependent manner. UVA, UVB and IRA reduced collagen Ialpha1 expression. Incubation with Trx inhibited the effects of UVB and IRA on collagen Ialpha1 expression. In conclusion, MMP-1 and collagen Ialpha1, which play important roles in aging processes, seems to be regulated by different transcriptional mechanisms and Trx can only influence distinct signaling pathways induced by UVA, UVB and probably IRA. Thus, Trx may serve as an important contributor to an "anti-aging therapeutic cocktail".

  16. Condensed cellular seeded collagen gel as an improved biomaterial for tissue engineering of articular cartilage.

    PubMed

    Mueller-Rath, Ralf; Gavénis, Karsten; Andereya, Stefan; Mumme, Torsten; Albrand, Monique; Stoffel, Marcus; Weichert, Dieter; Schneider, Ulrich

    2010-01-01

    Three-dimensional autologous chondrocyte implantation based on collagen gel as matrix scaffold has become a clinically applied treatment for focal defects of articular cartilage. However, the low biomechanical properties of collagen gel makes intraoperative handling difficult and creates the risk of early damages to the vulnerable implant. The aim of the study was to create a stabilized form of collagen gel and to evaluate its biomechanical and biochemical properties.Collagen type-I gel was seeded with human articular chondrocytes. 20 samples were subject to condensation which was achieved mechanically by compression and filtration. Control samples were left uncondensed. From both types of gels 10 samples were used for initial biomechanical evaluation by means of unconfined compression and 10 samples were cultivated under standard conditions in vitro. Following cultivation the samples were evaluated by conventional histology and immunohistochemistry. The proliferation rate was calculated and matrix gene expression was quantified by real-time PCR.The biomechanical tests revealed a higher force carrying capacity of the condensed specimens. Strain rate dependency and relaxation was seen in both types of collagen gel representing viscoelastic material properties. Cells embedded within the condensed collagen gel were able to produce extracellular matrix proteins and showed proliferation.Condensed collagen gel represents a mechanically improved type of biomaterial which is suitable for three-dimensional autologous chondrocyte implantation.

  17. Exposure of bovine dermal tissue to ultraviolet light under the Antarctic ozone hole

    NASA Astrophysics Data System (ADS)

    Takahashi, Tetsuya; Ogura, Takayuki; Tanaka, Keisuke; Hattori, Shunji; Kudoh, Sakae; Imura, Satoshi

    2016-12-01

    Bovine dermis was exposed outdoors in the Antarctic in 2013 to study the skin damage caused by short-wavelength ultraviolet light under the ozone hole. Collagen was extracted from the exposed dermis with pepsin. The amount of solubilized collagen in the exposed dermis was only 20%-40% of that in dermis shielded from ultraviolet light. The dermis was most difficult to extract when exposed in summer, and then when exposed in spring. Differential scanning calorimetry was used to determine the melting endothermic behavior of the dermal tissue. The peak temperature was highest for the dermis exposed in summer. The exposed dermis was degraded with cyanogen bromide to determine whether cross-linking had occurred. Cross-linked peptides were detected in the dermis exposed in summer or spring, but the dermis exposed in autumn did not differ markedly from the light-shielded dermis. These data show that cross-linkages were readily formed in the collagen molecule chains in dermis exposed to ultraviolet light in summer, when solar elevation is highest and the period of sunshine is longest. A comparison of the dermis exposed in spring and that exposed in autumn showed that cross-linkages were formed more readily by ultraviolet light in spring, when the ozone hole occurred.

  18. Collagen fibrils: nanoscale ropes.

    PubMed

    Bozec, Laurent; van der Heijden, Gert; Horton, Michael

    2007-01-01

    The formation of collagen fibrils from staggered repeats of individual molecules has become "accepted" wisdom. However, for over thirty years now, such a model has failed to resolve several structural and functional questions. In a novel approach, it was found, using atomic force microscopy, that tendon collagen fibrils are composed of subcomponents in a spiral disposition-that is, their structure is similar to that of macroscale ropes. Consequently, this arrangement was modeled and confirmed using elastic rod theory. This work provides new insight into collagen fibril structure and will have wide application-from the design of scaffolds for tissue engineering and a better understanding of pathogenesis of diseases of bone and tendon, to the conservation of irreplaceable parchment-based museum exhibits.

  19. Collagen Hydrogel Scaffold and Fibroblast Growth Factor-2 Accelerate Periodontal Healing of Class II Furcation Defects in Dog

    PubMed Central

    Momose, Takehito; Miyaji, Hirofumi; Kato, Akihito; Ogawa, Kosuke; Yoshida, Takashi; Nishida, Erika; Murakami, Syusuke; Kosen, Yuta; Sugaya, Tsutomu; Kawanami, Masamitsu

    2016-01-01

    Objective: Collagen hydrogel scaffold exhibits bio-safe properties and facilitates periodontal wound healing. However, regenerated tissue volume is insufficient. Fibroblast growth factor-2 (FGF2) up-regulates cell behaviors and subsequent wound healing. We evaluated whether periodontal wound healing is promoted by application of collagen hydrogel scaffold in combination with FGF2 in furcation defects in beagle dogs. Methods: Collagen hydrogel was fabricated from bovine type I collagen with an ascorbate-copper ion cross-linking system. Collagen hydrogel was mingled with FGF2 and injected into sponge-form collagen. Subsequently, FGF2 (50 µg)/collagen hydrogel scaffold and collagen hydrogel scaffold alone were implanted into class II furcation defects in dogs. In addition, no implantation was performed as a control. Histometric parameters were assessed at 10 days and 4 weeks after surgery. Result: FGF2 application to scaffold promoted considerable cell and tissue ingrowth containing numerous cells and blood vessel-like structure at day 10. At 4 weeks, reconstruction of alveolar bone was stimulated by implantation of scaffold loaded with FGF2. Furthermore, periodontal attachment, consisting of cementum-like tissue, periodontal ligament-like tissue and Sharpey’s fibers, was also repaired, indicating that FGF2-loaded scaffold guided self-assembly and then re-established the function of periodontal organs. Aberrant healing, such as ankylosis and root resorption, was not observed. Conclusion: FGF2-loaded collagen hydrogel scaffold possessed excellent biocompatibility and strongly promoted periodontal tissue engineering, including periodontal attachment re-organization. PMID:27583044

  20. Dermal mass aspirate from a Persian cat.

    PubMed

    Zimmerman, Kurt; Feldman, Bernard; Robertson, John; Herring, Erin S; Manning, Thomas

    2003-01-01

    A 1-year-old spayed female Persian cat with alopecia and weight loss had numerous variably ulcerated dermal nodules. Cytologic examination of an aspirate of one of the nodules revealed pyogranulomatous inflammation along with septate hyphae and basophilic round bodies, 0.5-1.0 microm in diameter, surrounded by a thin clear halo (arthrospores). The cytologic diagnosis was dermatophytic pseudomycetoma. Histologically, there were dermal granulomas containing poorly staining, septate hyphae with bulbous spores embedded within abundant amorphous eosinophilic material (Splendore-Hoeppli reaction), and the histologic diagnosis was pseudomycetoma-associated chronic multifocal severe granulomatous dermatitis with lymphocytic perifolliculitis and furunculosis. Microsporum canis was cultured from the lesion. Pseudomycetomas are distinguished from fungal mycetomas, or eumycotic mycetomas, by the findings of multiple lesions, lack of a history of skin trauma, an association with dermatophytes, most commonly Microsporum canis, and, histologically, lack of true cement material and a more abundant Splendore-Hoeppli reaction in pseudomycetomas. Additionally, pseudomycetomas differ from dermatophytosis, in which lesions are restricted to epidermal structures. Persian cats have a high incidence of pseudomycetoma formation, suggesting a heritable predisposition. The prognosis is fair with systemic antifungal therapy. When examining cytologic specimens from Persian cats with single or multiple dermal nodules, especially if pyogranulomatous inflammation is present, a diagnosis of pseudomycetoma should be suspected and is warranted if arthrospores and refractile septate hyphae are present.

  1. A Comparison of Conventional Collagen Sponge and Collagen-Gelatin Sponge in Wound Healing

    PubMed Central

    Jinno, Chizuru; Morimoto, Naoki; Ito, Ran; Sakamoto, Michiharu; Ogino, Shuichi; Taira, Tsuguyoshi; Suzuki, Shigehiko

    2016-01-01

    The objective of this study was to compare the effectiveness of the collagen-gelatin sponge (CGS) with that of the collagen sponge (CS) in dermis-like tissue regeneration. CGS, which achieves the sustained release of basic fibroblast growth factor (bFGF), is a promising material in wound healing. In the present study, we evaluated and compared CGSs and conventional CSs. We prepared 8 mm full-thickness skin defects on the backs of rats. Either CGSs or CSs were impregnated with normal saline solution (NSS) or 7 μg/cm2 of bFGF solution and implanted into the defects. At 1 and 2 weeks after implantation, tissue specimens were obtained from the rats of each group (n = 3, total n = 24). The wound area, neoepithelial length, dermis-like tissue area, and the number and area of capillaries were evaluated at 1 and 2 weeks after implantation. There were no significant differences in the CGS without bFGF and CS groups. Significant improvements were observed in the neoepithelial length, the dermis-like tissue area, and the number of newly formed capillaries in the group of rats that received CGSs impregnated with bFGF. The effects on epithelialization, granulation, and vascularization of wound healing demonstrated that, as a scaffold, CGSs are equal or superior to conventional CSs. PMID:27218103

  2. A Comparison of Conventional Collagen Sponge and Collagen-Gelatin Sponge in Wound Healing.

    PubMed

    Jinno, Chizuru; Morimoto, Naoki; Ito, Ran; Sakamoto, Michiharu; Ogino, Shuichi; Taira, Tsuguyoshi; Suzuki, Shigehiko

    2016-01-01

    The objective of this study was to compare the effectiveness of the collagen-gelatin sponge (CGS) with that of the collagen sponge (CS) in dermis-like tissue regeneration. CGS, which achieves the sustained release of basic fibroblast growth factor (bFGF), is a promising material in wound healing. In the present study, we evaluated and compared CGSs and conventional CSs. We prepared 8 mm full-thickness skin defects on the backs of rats. Either CGSs or CSs were impregnated with normal saline solution (NSS) or 7 μg/cm(2) of bFGF solution and implanted into the defects. At 1 and 2 weeks after implantation, tissue specimens were obtained from the rats of each group (n = 3, total n = 24). The wound area, neoepithelial length, dermis-like tissue area, and the number and area of capillaries were evaluated at 1 and 2 weeks after implantation. There were no significant differences in the CGS without bFGF and CS groups. Significant improvements were observed in the neoepithelial length, the dermis-like tissue area, and the number of newly formed capillaries in the group of rats that received CGSs impregnated with bFGF. The effects on epithelialization, granulation, and vascularization of wound healing demonstrated that, as a scaffold, CGSs are equal or superior to conventional CSs.

  3. Characterization of dermal structural assembly in normal and pathological connective tissues by intrinsic signal multiphoton optical microscopy

    NASA Astrophysics Data System (ADS)

    Lyubovitsky, Julia G.; Xu, Xiaoman; Sun, Chung-ho; Andersen, Bogi; Krasieva, Tatiana B.; Tromberg, Bruce J.

    2008-02-01

    Employing a reflectance multi-photon microscopy (MPM) technique, we developed novel method to quantitatively study the three-dimensional assembly of structural proteins within bulk of dermal ECMs. Using a structurally simplified model of skin with enzymatically dissected epidermis, we find that low resolution MPM clearly discriminates between normal and pathological dermis. High-resolution images revealed that the backscattered MPM signals are affected by the assembly of collagen fibrils and fibers within this system. Exposure of tissues to high concentrations of potentially denaturing chemicals also resulted in the reduction of SHG signals from structural proteins which coincided with the appearance of aggregated fluorescent structures.

  4. Collagen in organ development

    NASA Technical Reports Server (NTRS)

    Hardman, P.; Spooner, B. S.

    1992-01-01

    It is important to know whether microgravity will adversely affect developmental processes. Collagens are macromolecular structural components of the extracellular matrix (ECM) which may be altered by perturbations in gravity. Interstitial collagens have been shown to be necessary for normal growth and morphogenesis in some embryonic organs, and in the mouse salivary gland, the biosynthetic pattern of these molecules changes during development. Determination of the effects of microgravity on epithelial organ development must be preceded by crucial ground-based studies. These will define control of normal synthesis, secretion, and deposition of ECM macromolecules and the relationship of these processes to morphogenesis.

  5. Evaluation of electric arc furnace-processed steel slag for dermal corrosion, irritation, and sensitization from dermal contact.

    PubMed

    Suh, Mina; Troese, Matthew J; Hall, Debra A; Yasso, Blair; Yzenas, John J; Proctor, Debora M

    2014-12-01

    Electric arc furnace (EAF) steel slag is alkaline (pH of ~11-12) and contains metals, most notably chromium and nickel, and thus has potential to cause dermal irritation and sensitization at sufficient dose. Dermal contact with EAF slag occurs in many occupational and environmental settings because it is used widely in construction and other industrial sectors for various applications including asphaltic paving, road bases, construction fill, and as feed for cement kilns construction. However, no published study has characterized the potential for dermal effects associated with EAF slag. To assess dermal irritation, corrosion and sensitizing potential of EAF slag, in vitro and in vivo dermal toxicity assays were conducted based on the Organisation for Economic Co-operation and Development (OECD) guidelines. In vitro dermal corrosion and irritation testing (OECD 431 and 439) of EAF slag was conducted using the reconstructed human epidermal (RHE) tissue model. In vivo dermal toxicity and delayed contact sensitization testing (OECD 404 and 406) were conducted in rabbits and guinea pigs, respectively. EAF slag was not corrosive and not irritating in any tests. The results of the delayed contact dermal sensitization test indicate that EAF slag is not a dermal sensitizer. These findings are supported by the observation that metals in EAF slag occur as oxides of low solubility with leachates that are well below toxicity characteristic leaching procedure (TCLP) limits. Based on these results and in accordance to the OECD guidelines, EAF slag is not considered a dermal sensitizer, corrosive or irritant.

  6. Corneal Collagen Cross-Linking

    PubMed Central

    Jankov II, Mirko R.; Jovanovic, Vesna; Nikolic, Ljubisa; Lake, Jonathan C.; Kymionis, Georgos; Coskunseven, Efekan

    2010-01-01

    Corneal collagen cross-linking (CXL) with riboflavin and ultraviolet-A (UVA) is a new technique of corneal tissue strengthening by using riboflavin as a photosensitizer and UVA to increase the formation of intra and interfibrillar covalent bonds by photosensitized oxidation. Keratocyte apoptosis in the anterior segment of the corneal stroma all the way down to a depth of about 300 microns has been described and a demarcation line between the treated and untreated cornea has been clearly shown. It is important to ensure that the cytotoxic threshold for the endothelium has not been exceeded by strictly respecting the minimal corneal thickness. Confocal microscopy studies show that repopulation of keratocytes is already visible 1 month after the treatment, reaching its pre-operative quantity and quality in terms of functional morphology within 6 months after the treatment. The major indication for the use of CXL is to inhibit the progression of corneal ectasias, such as keratoconus and pellucid marginal degeneration. CXL may also be effective in the treatment and prophylaxis of iatrogenic keratectasia, resulting from excessively aggressive photoablation. This treatment has also been used to treat infectious corneal ulcers with apparent favorable results. Combination with other treatments, such as intracorneal ring segment implantation, limited topography-guided photoablation and conductive keratoplasty have been used with different levels of success. PMID:20543933

  7. Structure and function of collagen types

    SciTech Connect

    Mayne, R.; Burgeson, R.E.

    1987-01-01

    This book contains 10 chapters. Some of the chapter titles are: The Classical Collagens: Types I, II, and III; Type IV Collagen; Type IX Collagen; and Analysis of Collagen Structure by Molecular Biology Techniques.

  8. [The genetics of collagen diseases].

    PubMed

    Kaplan, J; Maroteaux, P; Frezal, J

    1986-01-01

    Heritable disorders of collagen include Ehler-Danlos syndromes (11 types are actually known), Larsen syndrome and osteogenesis imperfecta. Their clinical, genetic and biochemical features are reviewed. Marfan syndrome is closely related to heritable disorders of collagen.

  9. Implantable Microimagers

    PubMed Central

    Ng, David C.; Tokuda, Takashi; Shiosaka, Sadao; Tano, Yasuo; Ohta, Jun

    2008-01-01

    Implantable devices such as cardiac pacemakers, drug-delivery systems, and defibrillators have had a tremendous impact on the quality of live for many disabled people. To date, many devices have been developed for implantation into various parts of the human body. In this paper, we focus on devices implanted in the head. In particular, we describe the technologies necessary to create implantable microimagers. Design, fabrication, and implementation issues are discussed vis-à-vis two examples of implantable microimagers; the retinal prosthesis and in vivo neuro-microimager. Testing of these devices in animals verify the use of the microimagers in the implanted state. We believe that further advancement of these devices will lead to the development of a new method for medical and scientific applications. PMID:27879873

  10. Evaluation of the immunogenicity and cell compatibility of avian collagen for biomedical applications.

    PubMed

    Peng, Yong Y; Glattauer, Veronica; Ramshaw, John A M; Werkmeister, Jerome A

    2010-06-15

    There have been concerns regarding the suitability of bovine collagen as a biomaterial since the emergence of bovine spongiform encephalopathy. Consequently, collagens from other species may be used if they can meet appropriate standards, including negligible or lack of immunogenicity. In this study, the potential immunogenicity of both monomeric and pepsin-solubilized chicken collagens have been compared with a commercial, pepsin-solubilized bovine collagen that is approved for biomedical implantation. All collagens were poor immunogens compared with ovalbumin. No IgE responses were detected in sera of three strains of mice, and no hypersensitivity reactions were found in guinea pigs in maximization and Buehler tests. IgG(1) antibodies were found although the titre was substantially lower than against ovalbumin. All responses in mice and rabbits were found only when immunizations were performed with adjuvant, and after multiple injections over a long period of time. The response from the monomeric chicken collagen was less than for pepsin-solubilized collagens. Collagen sponges prepared from the two chicken collagen preparations both supported the attachment and growth of mouse fibroblasts. These data indicate that chicken collagen, particularly when monomeric, may be useful in certain biomedical applications.

  11. Collagen Self-Assembly on Orthopedic Magnesium Biomaterials Surface and Subsequent Bone Cell Attachment

    PubMed Central

    Zhao, Nan; Zhu, Donghui

    2014-01-01

    Magnesium (Mg) biomaterials are a new generation of biodegradable materials and have promising potential for orthopedic applications. After implantation in bone tissues, these materials will directly interact with extracellular matrix (ECM) biomolecules and bone cells. Type I collagen, the major component of bone ECM, forms the architecture scaffold that provides physical support for bone cell attachment. However, it is still unknown how Mg substrate affects collagen assembly on top of it as well as subsequent cell attachment and growth. Here, we studied the effects of collagen monomer concentration, pH, assembly time, and surface roughness of two Mg materials (pure Mg and AZ31) on collagen fibril formation. Results showed that formation of fibrils would not initiate until the monomer concentration reached a certain level depending on the type of Mg material. The thickness of collagen fibril increased with the increase of assembly time. The structures of collagen fibrils formed on semi-rough surfaces of Mg materials have a high similarity to that of native bone collagen. Next, cell attachment and growth after collagen assembly were examined. Materials with rough surface showed higher collagen adsorption but compromised bone cell attachment. Interestingly, surface roughness and collagen structure did not affect cell growth on AZ31 for up to a week. Findings from this work provide some insightful information on Mg-tissue interaction at the interface and guidance for future surface modifications of Mg biomaterials. PMID:25303459

  12. Protective Effects of Triphala on Dermal Fibroblasts and Human Keratinocytes

    PubMed Central

    Varma, Sandeep R.; Sivaprakasam, Thiyagarajan O.; Mishra, Abheepsa; Kumar, L. M. Sharath; Prakash, N. S.; Prabhu, Sunil; Ramakrishnan, Shyam

    2016-01-01

    Human skin is body’s vital organ constantly exposed to abiotic oxidative stress. This can have deleterious effects on skin such as darkening, skin damage, and aging. Plant-derived products having skin-protective effects are well-known traditionally. Triphala, a formulation of three fruit products, is one of the most important rasayana drugs used in Ayurveda. Several skin care products based on Triphala are available that claim its protective effects on facial skin. However, the skin protective effects of Triphala extract (TE) and its mechanistic action on skin cells have not been elucidated in vitro. Gallic acid, ellagic acid, and chebulinic acid were deduced by LC-MS as the major constituents of TE. The identified key compounds were docked with skin-related proteins to predict their binding affinity. The IC50 values for TE on human dermal fibroblasts (HDF) and human keratinocytes (HaCaT) were 204.90 ± 7.6 and 239.13 ± 4.3 μg/mL respectively. The antioxidant capacity of TE was 481.33 ± 1.5 mM Trolox equivalents in HaCaT cells. Triphala extract inhibited hydrogen peroxide (H2O2) induced RBC haemolysis (IC50 64.95 μg/mL), nitric oxide production by 48.62 ± 2.2%, and showed high reducing power activity. TE also rescued HDF from H2O2-induced damage; inhibited H2O2 induced cellular senescence and protected HDF from DNA damage. TE increased collagen-I, involucrin and filaggrin synthesis by 70.72 ± 2.3%, 67.61 ± 2.1% and 51.91 ± 3.5% in HDF or HaCaT cells respectively. TE also exhibited anti-tyrosinase and melanin inhibition properties in a dose-dependent manner. TE increased the mRNA expression of collagen-I, elastin, superoxide dismutase (SOD-2), aquaporin-3 (AQP-3), filaggrin, involucrin, transglutaminase in HDF or HaCaT cells, and decreased the mRNA levels of tyrosinase in B16F10 cells. Thus, Triphala exhibits protective benefits on skin cells in vitro and can be used as a potential ingredient in skin care formulations. PMID:26731545

  13. Dimethyl 3,3'-dithiobispropionimidate: a novel crosslinking reagent for collagen.

    PubMed

    Charulatha, V; Rajaram, A

    2001-01-01

    Crosslinking agents are used for improving the physical properties and durability of collagenous implants, glutaraldehyde (GTA) being the most widely used. Many of these reagents, including GTA, are known to be cytotoxic and to induce calcification. Hence, it is desirable to develop new crosslinking methods for collagen, so that biocompatibility and physical properties are improved. In the present study, dimethyl 3,3' -dithiobispropionimidate (DTBP) has been tried as a novel crosslinking reagent for collagen. Collagen purified from rat tail tendon has been crosslinked with DTBP and GTA. An increase of 22 degrees C in shrinkage temperature is observed for collagen treated with DTBP under optimal conditions. Crosslinking density determination shows that DTBP induces 10 crosslinks per mole, compared to 13 by GTA. While the tensile strength of GTA-treated samples is greater than those treated with DTBP, the latter shows more extensibility. In vitro degradation studies show that both GTA- and DTBP-treated samples are resistant to degradation by collagenase. The biocompatibility of crosslinked collagen samples studied by subcutaneous implantation in rats show that while both GTA- and DTBP-treated collagen do not degrade for up to 4 weeks, ultrastructural and histological studies indicate that DTBP collagen is far more biocompatible than GTA-treated matrices.

  14. Endodontic implants

    PubMed Central

    Yadav, Rakesh K.; Tikku, A. P.; Chandra, Anil; Wadhwani, K. K.; Ashutosh kr; Singh, Mayank

    2014-01-01

    Endodontic implants were introduced back in 1960. Endodontic implants enjoyed few successes and many failures. Various reasons for failures include improper case selection, improper use of materials and sealers and poor preparation for implants. Proper case selection had given remarkable long-term success. Two different cases are being presented here, which have been treated successfully with endodontic implants and mineral trioxide aggregate Fillapex (Andreaus, Brazil), an MTA based sealer. We suggest that carefully selected cases can give a higher success rate and this method should be considered as one of the treatment modalities. PMID:25298723

  15. Collagen hydrolysate based collagen/hydroxyapatite composite materials

    NASA Astrophysics Data System (ADS)

    Ficai, Anton; Albu, Madalina Georgiana; Birsan, Mihaela; Sonmez, Maria; Ficai, Denisa; Trandafir, Viorica; Andronescu, Ecaterina

    2013-04-01

    The aim of this study was to study the influence of collagen hydrolysate (HAS) on the formation of ternary collagen-hydrolysate/hydroxyapatite composite materials (COLL-HAS/HA). During the precipitation process of HA, a large amount of brushite is resulted at pH = 7 but, practically pure HA is obtained at pH ⩾ 8. The FTIR data reveal the duplication of the most important collagen absorption bands due to the presence of the collagen hydrolysate. The presence of collagen hydrolysate is beneficial for the management of bone and joint disorders such as osteoarthritis and osteoporosis.

  16. Electrospun polyvinyl alcohol-collagen-hydroxyapatite nanofibers: a biomimetic extracellular matrix for osteoblastic cells

    NASA Astrophysics Data System (ADS)

    Song, Wei; Markel, David C.; Wang, Sunxi; Shi, Tong; Mao, Guangzhao; Ren, Weiping

    2012-03-01

    The failure of prosthesis after total joint replacement is due to the lack of early implant osseointegration. In this study polyvinyl alcohol-collagen-hydroxyapatite (PVA-Col-HA) electrospun nanofibrous meshes were fabricated as a biomimetic bone-like extracellular matrix for the modification of orthopedic prosthetic surfaces. In order to reinforce the PVA nanofibers, HA nanorods and Type I collagen were incorporated into the nanofibers. We investigated the morphology, biodegradability, mechanical properties and biocompatibility of the prepared nanofibers. Our results showed these inorganic-organic blended nanofibers to be degradable in vitro. The encapsulated nano-HA and collagen interacted with the PVA content, reinforcing the hydrolytic resistance and mechanical properties of nanofibers that provided longer lasting stability. The encapsulated nano-HA and collagen also enhanced the adhesion and proliferation of murine bone cells (MC3T3) in vitro. We propose the PVA-Col-HA nanofibers might be promising modifying materials on implant surfaces for orthopedic applications.

  17. Photopatterned collagen-hyaluronic acid interpenetrating polymer network hydrogels.

    PubMed

    Suri, Shalu; Schmidt, Christine E

    2009-09-01

    To engineer complex tissues, it is necessary to create hybrid scaffolds with micropatterned structural and biomechanical properties, which can closely mimic the intricate body tissues. The current report describes the synthesis of a novel photocrosslinkable interpenetrating polymeric network (IPN) of collagen and hyaluronic acid (HA) with precisely controlled structural and biomechanical properties. Both collagen and HA are present in crosslinked form in IPNs, and the two networks are entangled with each other. IPNs were also compared with semi-IPNs (SIPN), in which only collagen was in network form and HA chains were entangled in the collagen network without being photocrosslinked. Scanning electron microscopy images revealed that IPNs are denser than SIPNs, which results in their molecular reinforcement. This was further confirmed by rheological experiments. Because of the presence of the HA crosslinked network, the storage modulus of IPNs was almost two orders of magnitude higher than SIPNs. The degradation of the collagen-HA IPNs was slower than the SIPNs because of the presence of the crosslinked HA network. Increasing concentration of HA further altered the properties among IPNs. Cytocompatibility of IPNs was confirmed by Schwann cell and dermal fibroblasts adhesion and proliferation studies. We also fabricated patterned scaffolds with regions of IPNs and SIPNs within a bulk hydrogel, resulting in zonal distribution of crosslinking densities, viscoelasticities, water content and pore sizes at the micro- and macro-scales. With the ability to fine-tune the scaffold properties by performing structural modifications and to create patterned scaffolds, these hydrogels can be employed as potential candidates for regenerative medicine applications.

  18. Breast Implants

    MedlinePlus

    ... sale in the United States: saline-filled and silicone gel-filled. Both types have a silicone outer shell. They vary in size, shell thickness, ... implant them. Provide information on saline-filled and silicone gel-filled breast implants, including data supporting a ...

  19. Reduction of facial wrinkles by hydrolyzed water-soluble egg membrane associated with reduction of free radical stress and support of matrix production by dermal fibroblasts

    PubMed Central

    Jensen, Gitte S; Shah, Bijal; Holtz, Robert; Patel, Ashok; Lo, Donald C

    2016-01-01

    Objective The aim of this study was to evaluate the effects of water-soluble egg membrane (WSEM) on wrinkle reduction in a clinical pilot study and to elucidate specific mechanisms of action using primary human immune and dermal cell-based bioassays. Methods To evaluate the effects of topical application of WSEM (8%) on human skin, an open-label 8-week study was performed involving 20 healthy females between the age of 45 years and 65 years. High-resolution photography and digital analysis were used to evaluate the wrinkle depth in the facial skin areas beside the eye (crow’s feet). WSEM was tested for total antioxidant capacity and effects on the formation of reactive oxygen species by human polymorphonuclear cells. Human keratinocytes (HaCaT cells) were used for quantitative polymerase chain reaction analysis of the antioxidant response element genes Nqo1, Gclm, Gclc, and Hmox1. Evaluation of effects on human primary dermal fibroblasts in vitro included cellular viability and production of the matrix components collagen and elastin. Results Topical use of a WSEM-containing facial cream for 8 weeks resulted in a significant reduction of wrinkle depth (P<0.05). WSEM contained antioxidants and reduced the formation of reactive oxygen species by inflammatory cells in vitro. Despite lack of a quantifiable effect on Nrf2, WSEM induced the gene expression of downstream Nqo1, Gclm, Gclc, and Hmox1 in human keratinocytes. Human dermal fibroblasts treated with WSEM produced more collagen and elastin than untreated cells or cells treated with dbcAMP control. The increase in collagen production was statistically significant (P<0.05). Conclusion The topical use of WSEM on facial skin significantly reduced the wrinkle depth. The underlying mechanisms of this effect may be related to protection from free radical damage at the cellular level and induction of several antioxidant response elements, combined with stimulation of human dermal fibroblasts to secrete high levels of

  20. Controlled release of an extract of Calendula officinalis flowers from a system based on the incorporation of gelatin-collagen microparticles into collagen I scaffolds: design and in vitro performance.

    PubMed

    Jiménez, Ronald A; Millán, Diana; Suesca, Edward; Sosnik, Alejandro; Fontanilla, Marta R

    2015-06-01

    Aiming to develop biological skin dresses with improved performance in the treatment of skin wounds, acellular collagen I scaffolds were modified with polymeric microparticles and the subsequent loading of a hydroglycolic extract of Calendula officinalis flowers. Microparticles made of gelatin-collagen were produced by a water-in-oil emulsion/cross-linking method. Thereafter, these microparticles were mixed with collagen suspensions at three increasing concentrations and the resulting mixtures lyophilized to make microparticle-loaded porous collagen scaffolds. Resistance to enzymatic degradation, ability to associate with the C. officinalis extract, and the extract release profile of the three gelatin-collagen microparticle-scaffold prototypes were assessed in vitro and compared to collagen scaffolds without microparticles used as control. Data indicated that the incorporation of gelatin-collagen microparticles increased the resistance of the scaffolds to in vitro enzymatic degradation, as well as their association with the C. officinalis flower extract. In addition, a sharp decrease in cytotoxicity, as well as more prolonged release of the extract, was attained. Overall results support the potential of these systems to develop innovative dermal substitutes with improved features. Furthermore, the gelatin-collagen mixture represents a low-cost and scalable alternative with high clinical transferability, especially appealing in developing countries.

  1. Collagen-1 Membrane for Replacing the Bladder Wall.

    PubMed

    Kirpatovskii, V I; Efimenko, A Yu; Sysoeva, V Yu; Mudraya, I S; Kamalov, D M; Akopyan, Zh A; Kamalov, A A

    2016-11-01

    We studied the possibility of using membrane fabricated from type 1 collagen isolated from cattle tissues (group 1) or porcine tissues (group 2) for replacement of the resected bladder wall defect in rabbits in order to retain functional volume of the organ. Satisfactory take of both types of collagen membranes with formation of competent anastomosis was observed. Histological studies revealed inflammatory process in the bladder wall at the site of contact with the implanted membrane (more pronounced in case of membranes from cattle tissues) that decreased by day 21 of the experiment. Bladder tissue ingrowth into the implant from was observed starting from day 14. The bladder capacity decreased in 7 days after surgery in both groups, presumably because of increasing tone of the organ wall resulting from surgical trauma and inflammation. In group 2, the bladder volume increased by day 14 after surgery and returned to normal by day 21, whereas in group 1 it remained below the control despite a trend to increase. These findings confirm good prospects of using collagen-1 membranes for plastic repair of the urinary bladder, the membranes from porcine collagen being more preferable.

  2. Persistent cutaneous abdominal ulcerations secondary to diffuse dermal angiomatosis: an underestimated sign for severe atherosclerosis

    PubMed Central

    García-Colmenero, Lidia; Martin-Ezquerra, Gemma; Gómez-Martín, Ignacio; Mellado Joan, Meritxell; Barranco, Carlos; Albero-González, Raquel; Villar-García, Judith; Pujol, Ramon M.

    2016-01-01

    Abstract Background: Diffuse dermal angiomatosis (DDA) is a rare, acquired, reactive vascular proliferation, clinically characterized by livedoid erythematous–violaceous plaques, which frequently evolve to ulceration and necrosis. Histopathologically, it is manifested by a diffuse proliferation of endothelial cells within the full thickness of the dermis. DDA has been mainly associated with severe peripheral atherosclerosis. Methods: We report a 63-year-old woman who presented with multiple erythematous–violaceous plaques with central deep skin ulcers on thighs, lower abdomen, and perianal area, associated with intermittent claudication, low-grade fever, and weight loss. Initially, the clinical picture along with positive cultures for Klebsiella pneumoniae suggested a multifocal ecthyma gangrenosum; nevertheless, a skin biopsy showed a diffuse dermal proliferation of endothelial cells interstitially arranged between collagen bundles. A computed tomography scan revealed severe aortic atheromatosis with complete luminal occlusion of the infrarenal aorta and common iliac arteries. Results: The diagnosis of DDA secondary to severe atherosclerosis was established. The patient underwent a left axillofemoral bypass surgery with a rapidly healing of the ulcers in the next weeks. Conclusions: DDA should be considered in the differential diagnosis of livedoid ischemic lesions. Recognition of DDA as a cutaneous sign of severe peripheral vascular disease is important for both dermatologists and internists. Recognition of risk factors and their management with an early intervention to correct tissue ischemia can be curative. PMID:27442644

  3. Gelatin/Carboxymethyl chitosan based scaffolds for dermal tissue engineering applications.

    PubMed

    Agarwal, Tarun; Narayan, Rajan; Maji, Somnath; Behera, Shubhanath; Kulanthaivel, Senthilguru; Maiti, Tapas Kumar; Banerjee, Indranil; Pal, Kunal; Giri, Supratim

    2016-12-01

    The present study delineates the preparation, characterization and application of gelatin-carboxymethyl chitosan scaffolds for dermal tissue engineering. The effect of carboxymethyl chitosan and gelatin ratio was evaluated for variations in their physico-chemical-biological characteristics and drug release kinetics. The scaffolds were prepared by freeze drying method and characterized by SEM and FTIR. The study revealed that the scaffolds were highly porous with pore size ranging between 90 and 170μm, had high water uptake (400-1100%) and water retention capacity (>300%). The collagenase mediated degradation of the scaffolds was dependent on the amount of gelatin present in the formulation. A slight yet significant variation in their biological characteristics was also observed. All the formulations supported adhesion, spreading, growth and proliferation of 3T3 mouse fibroblasts. The cells seeded on the scaffolds also demonstrated expression of collagen type I, HIF1α and VEGF, providing a clue regarding their growth and proliferation along with potential to support angiogenesis during wound healing. In addition, the scaffolds showed sustained ampicillin and bovine serum albumin release, confirming their suitability as a therapeutic delivery vehicle during wound healing. All together, the results suggest that gelatin-carboxymethyl chitosan based scaffolds could be a suitable matrix for dermal tissue engineering applications.

  4. Hip Capsular Reconstruction Using Dermal Allograft.

    PubMed

    Chahla, Jorge; Dean, Chase S; Soares, Eduardo; Mook, William R; Philippon, Marc J

    2016-04-01

    Because hip arthroscopic procedures are increasing in number, complications related to the operation itself are starting to emerge. Whereas the capsule has been recognized as an important static stabilizer for the hip, it has not been until recently that surgeons have realized the importance of its preservation and restoration. Disruption of the capsule during arthroscopic procedures is a potential contributor to postoperative iatrogenic hip instability. In cases of a symptomatic deficient capsule, a capsular reconstruction is mandatory because instability may lead to detrimental chondral and labral changes. The purpose of this report was to describe our technique for arthroscopic hip capsular reconstruction using dermal allograft.

  5. Melatonin plus porcine bone on discrete calcium deposit implant surface stimulates osteointegration in dental implants.

    PubMed

    Calvo-Guirado, José Luis; Gómez-Moreno, Gerardo; Barone, Antonio; Cutando, Antonio; Alcaraz-Baños, Miguel; Chiva, Fernando; López-Marí, Laura; Guardia, Javier

    2009-09-01

    The aim of this study was to evaluate the effect of the topical application of melatonin mixed with collagenized porcine bone to accelerate the osteointegration on the rough discrete calcium deposit (DCD) surface implants in Beagle dogs 3 months after their insertion. In preparation for subsequent insertion of dental implants, lower premolars and molars were extracted from 12 Beagle dogs. Each mandible received three parallel wall implants with discrete calcium deposit (DCD) surface of 4 mm in diameter and 10 mm in length. The implants were randomly assigned to the distal sites on each side of the mandible in three groups: group I implants alone, group II implants with melatonin and group III implants with melatonin and porcine bone. Prior to implanting, 5 mg lyophylized powdered melatonin was applied to one bone hole at each side of the mandible. None was applied at the control sites. Ten histological sections per implant were obtained for histomorphometric studies. After a 4-wk treatment period, melatonin significantly increased the perimeter of bone that was in direct contact with the treated implants (P < 0.0001), bone density (P < 0.0001), new bone formation (P < 0.0001) in comparison with control implants. Topical application of melatonin on DCD surface may act as a biomimetic agent in the placement of endo-osseous dental implants and enhance the osteointegration. Melatonin combined with porcine bone on DCD implants reveals more bone to implant contact at 12 wk (84.5 +/- 1.5%) compared with melatonin treated (75.1 +/- 1.4%) and nonmelatonin treated surface implants (64 +/- 1.4%).

  6. A Novel Reticular Dermal Graft Leverages Architectural and Biological Properties to Support Wound Repair

    PubMed Central

    Dasgupta, Anouska; Orgill, Dennis; Galiano, Robert D.; Zelen, Charles M.; Huang, Yen-Chen; Chnari, Evangelia; Li, William W.

    2016-01-01

    Background: Acellular dermal matrices (ADMs) are frequently used in reconstructive surgery and as scaffolds to treat chronic wounds. The 3-dimensional architecture and extracellular matrix provide structural and signaling cues for repair and remodeling. However, most ADMs are not uniformly porous, which can lead to heterogeneous host engraftment. In this study, we hypothesized that a novel human reticular ADM (HR-ADM; AlloPatch Pliable, Musculoskeletal Transplant Foundation, Edison, N.J.) when aseptically processed would have a more open uniform structure with retention of biological components known to facilitate wound healing. Methods: The reticular and papillary layers were compared through histology and scanning electron microscopy. Biomechanical properties were assessed through tensile testing. The impact of aseptic processing was evaluated by comparing unprocessed with processed reticular grafts. In vitro cell culture on fibroblasts and endothelial cells were performed to showcase functional cell activities on HR-ADMs. Results: Aseptically processed HR-ADMs have an open, interconnected uniform scaffold with preserved collagens, elastin, glycosaminoglycans, and hyaluronic acid. HR-ADMs had significantly lower ultimate tensile strength and Young’s modulus versus the papillary layer, with a higher percentage elongation at break, providing graft flexibility. These preserved biological components facilitated fibroblast and endothelial cell attachment, cell infiltration, and new matrix synthesis (collagen IV, fibronectin, von Willebrand factor), which support granulation and angiogenic activities. Conclusions: The novel HR-ADMs provide an open, interconnected scaffold with native dermal mechanical and biological properties. Furthermore, aseptic processing retains key extracellular matrix elements in an organized framework and supports functional activities of fibroblasts and endothelial cells. PMID:27826469

  7. Label-free nonenzymatic glycation monitoring of collagen scaffolds in type 2 diabetic mice by confocal Raman microspectroscopy

    NASA Astrophysics Data System (ADS)

    Shi, Panpan; Liu, Hanping; Deng, Xiaoyuan; Jin, Ying; Wang, Qiannan; Liu, Hao; Chen, Maosheng; Han, Xue

    2015-02-01

    Collagen is the key target of nonenzymatic glycation during physiopathological processes such as diabetes. The induced changes in the biochemical property of collagen by nonenzymatic glycation remain a major challenge to probe. This study investigated the use of confocal Raman microspectroscopy to label-free monitor the nonenzymatic glycation of collagen scaffolds from type 2 diabetic (T2D) mice at different timepoints (0, 4, 8, and 12 weeks). The glycated collagen scaffolds were obtained through the decellularized dermal matrix method to remove the epidermis layer, subcutaneous tissue, and cells in the dermis and to retain the collagen fibrils. Raman spectra showed no changes in Raman peak positions, which indicated that nonenzymatic glycation could produce no significant changes in the triple-helix structure of collagen in T2D mice. However, the relative intensity of the Raman bands at 921, 1033, 1244, 1274, 1346, 1635, and 1672 cm-1 increased as diabetic time progressed. Correlation analysis suggested that the spectra of these bands had a high positive correlation with the expression of anti-advanced glycation end products obtained by immunofluorescence imaging of the same collagen scaffolds. Confocal Raman microspectroscopy proves a potential tool to label-free monitor the collagen changes caused by nonenzymatic glycation in T2D mice.

  8. IL-13 mediates collagen deposition via STAT6 and microRNA-135b: a role for epigenetics

    PubMed Central

    O’Reilly, Steven; Ciechomska, Marzena; Fullard, Nicola; Przyborski, Stefan; van Laar, Jacob M.

    2016-01-01

    Systemic sclerosis is an autoimmune connective tissue disease in which T cells play a prominent role. We and others have previously demonstrated a role for T cell-derived IL-13 in mediating the induction of collagen in dermal fibroblasts and that blockade with IL-13 antibodies attenuates this increase. In this study we want to probe the signalling that underpins IL-13 mediated matrix deposition. Isolated dermal fibroblasts were incubated with recombinant IL-13 and gene expression by qRT-PCR was performed for collagen1A1 and TGF-β1. Small interfering RNA (siRNA) was used to knock down STAT6 and a small molecule inhibitor was also used to block this pathway. MiR-135b was transfected into fibroblasts plus and minus IL-13 to see if this miR plays a role. miR-135b was measured in systemic sclerosis fibroblasts isolated from patients and also in serum. Results showed that IL-13 increased collagen expression and that this is independent from TGF-β1. This is dependent on STAT6 as targeting this blocked induction. MiR-135b reduces collagen induction in fibroblasts and scleroderma fibroblasts have lower constitutive levels of the miR. We further demonstrate that miR135b is repressed by methylation and may include MeCP2. In conclusion we show that STAT6 and miR-135b regulate IL-13-mediated collagen production by fibroblasts. PMID:27113293

  9. A Novel Compound Rasatiol Isolated from Raphanus sativus Has a Potential to Enhance Extracellular Matrix Synthesis in Dermal Fibroblasts

    PubMed Central

    Roh, Seok-Seon; Park, Seung-Bae; Park, Seong-Mo; Choi, Byoung Wook; Lee, Min-Ho; Hwang, Yul-Lye; Kim, Chang Hun; Jeong, Hyun-Ah; Kim, Chang Deok

    2013-01-01

    Background The fibrous proteins of extracellular matrix (ECM) produced by dermal fibroblast contributes to the maintenance of connective tissue integrity. Objective This study is carried out to identify the bioactive ingredient from natural products that enhances ECM production in dermal fibroblasts. Methods Bioassay-directed fractionation was used to isolate the active ingredient from natural extracts. The effects of rasatiol (isolated from Raphanus sativus) on ECM production in primary cultured human dermal fibroblasts was investigated by enzyme linked immunosorbent assay and western blot analysis. Results Rasatiol accelerated fibroblast growth in a dose-dependent manner and increased the production of type 1 collagen, fibronectin and elastin. Phosphorylation of p42/44 extracellular signal-regulated kinase, p38 mitogen-activated protein kinase, and Akt was remarkably increased by rasatiol, indicating that enhanced ECM production is linked to the activation of intracellular signaling cascades. Conclusion These results indicate that rasatiol stimulates the fibrous components of ECM production, and may be applied to the maintenance of skin texture. PMID:24003274

  10. Mesenchymal stem cells induce dermal fibroblast responses to injury

    SciTech Connect

    Smith, Andria N.; Willis, Elise; Chan, Vincent T.; Muffley, Lara A.; Isik, F. Frank; Gibran, Nicole S.; Hocking, Anne M.

    2010-01-01

    Although bone marrow-derived mesenchymal stem cells have been shown to promote repair when applied to cutaneous wounds, the mechanism for this response remains to be determined. The aim of this study was to determine the effects of paracrine signaling from mesenchymal stem cells on dermal fibroblast responses to injury including proliferation, migration and expression of genes important in wound repair. Dermal fibroblasts were co-cultured with bone marrow-derived mesenchymal stem cells grown in inserts, which allowed for paracrine interactions without direct cell contact. In this co-culture model, bone marrow-derived mesenchymal stem cells regulate dermal fibroblast proliferation, migration and gene expression. When co-cultured with mesenchymal stem cells, dermal fibroblasts show increased proliferation and accelerated migration in a scratch assay. A chemotaxis assay also demonstrated that dermal fibroblasts migrate towards bone marrow-derived mesenchymal stem cells. A PCR array was used to analyze the effect of mesenchymal stem cells on dermal fibroblast gene expression. In response to mesenchymal stem cells, dermal fibroblasts up-regulate integrin alpha 7 expression and down-regulate expression of ICAM1, VCAM1 and MMP11. These observations suggest that mesenchymal stem cells may provide an important early signal for dermal fibroblast responses to cutaneous injury.

  11. CARD14 expression in dermal endothelial cells in psoriasis.

    PubMed

    Harden, Jamie L; Lewis, Steven M; Pierson, Katherine C; Suárez-Fariñas, Mayte; Lentini, Tim; Ortenzio, Francesca S; Zaba, Lisa C; Goldbach-Mansky, Raphaela; Bowcock, Anne M; Lowes, Michelle A

    2014-01-01

    Mutations in the caspase recruitment domain, family member 14 (CARD14) gene have recently been described in psoriasis patients, and explain the psoriasis susceptibility locus 2 (PSORS2). CARD14 is a scaffolding protein that regulates NF-κB activation, and psoriasis-associated CARD14 mutations lead to enhanced NF-κB signaling. CARD14 is expressed mainly in epidermal keratinocytes, but also in unidentified dermal cells. In this manuscript, the identity of the dermal cell types expressing CARD14, as well the potential functional consequence of overactive CARD14 in these dermal cell types, was determined. Using two-color immunofluorescence, dermal CARD14 did not co-localize with T-cells, dendritic cells, or macrophages. However, dermal CARD14 did highly co-localize with CD31(+) endothelial cells (ECs). CARD14 was also expressed non-dermal endothelial cells, such as aortic endothelial cells, which may indicate a role of CARD14(+)ECs in the systemic inflammation and cardiovascular comorbidities associated with psoriasis. Additionally, phosphorylated NF-κB was found in psoriatic CARD14(+) CD31(+) ECs, demonstrating this pathway is active in dermal ECs in psoriasis. Transfection of dermal ECs with psoriasis-associated CARD14 mutations resulted in increased expression of several chemokines, including CXCL10, IL-8, and CCL2. These results provide preliminary evidence that CARD14 expression in ECs may contribute to psoriasis through increased expression of chemokines and facilitating recruitment of immune cells into skin.

  12. IN VITRO DERMAL ABSORPTION OF FLAME RETARDANT CHEMICALS

    EPA Science Inventory

    ABSTRACT
    The use of flame retardant chemicals in furniture fabric could pose a potential health risk to consumers from dermal absorption of these compounds. The objective of this study was to examine the in vitro dermal absorption of two flame retardant chemicals, [14C]-d...

  13. Spectrum of PORCN mutations in Focal Dermal Hypoplasia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Focal Dermal Hypoplasia (FDH), also known as Goltz syndrome (OMIM 305600), is a genetic disorder that affects multiple organ systems early in development. Features of FDH include skin abnormalities, (hypoplasia, atrophy, linear pigmentation, and herniation of fat through dermal defects); papillomas...

  14. Investigation on the effect of collagen and vitamins on biomimetic hydroxyapatite coating formation on titanium surfaces.

    PubMed

    Ciobanu, Gabriela; Ciobanu, Octavian

    2013-04-01

    This study uses an in vitro experimental approach to investigate the roles of collagen and vitamins in regulating the deposition of hydroxyapatite layer on the pure titanium surface. Titanium implants were coated with a hydroxyapatite layer under biomimetic conditions by using a supersaturated calcification solution (SCS), modified by adding vitamins A and D3, and collagen. The hydroxyapatite deposits on titanium were investigated by means of scanning electron microscopy (SEM) coupled with X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) spectroscopy. The results obtained have shown that hydroxyapatite coatings were produced in vitro under vitamins and collagen influence.

  15. [Cerebellar abscesses secondary to infection of an occipital dermal sinus].

    PubMed

    García Galera, A; Martínez León, M I; Pérez da Rosa, S; Ros López, B

    2013-09-01

    A dermal sinus is a congenital defect arising from a closure failure of the neural tube that results in different degrees of communication between the skin and the central nervous system. A dermal sinus can occur anywhere from the root of the nose to the conus medullaris, and the occipital location is the second most common. Dermal sinuses are often found in association with dermoid or epidermoid cysts and less frequently with teratomas. Patients with an occipital dermoid cyst associated with a dermal sinus can develop meningitis and/or abscesses as the first clinical manifestation of the disease due to the dermoid cyst itself becoming abscessed or to the formation of secondary abscesses; few cases of the formation of secondary abscesses have been reported. We present a case of a dermoid cyst associated with an infected dermal sinus and posterior development of cerebellar abscesses and hydrocephalus.

  16. Conducting polymers with immobilised fibrillar collagen for enhanced neural interfacing.

    PubMed

    Liu, Xiao; Yue, Zhilian; Higgins, Michael J; Wallace, Gordon G

    2011-10-01

    Conducting polymers with pendant functionality are advantageous in various bionic and organic bioelectronic applications, as they allow facile incorporation of bio-regulative cues to provide bio-mimicry and conductive environments for cell growth, differentiation and function. In this work, polypyrrole substrates doped with chondroitin sulfate (CS), an extracellular matrix molecule bearing carboxylic acid moieties, were electrochemically synthesized and conjugated with type I collagen. During the coupling process, the conjugated collagen formed a 3-dimensional fibrillar matrix in situ at the conducting polymer interface, as evidenced by atomic force microscopy (AFM) and fluorescence microscopy under aqueous physiological conditions. Cyclic voltammetry (CV) and impedance measurement confirmed no significant reduction in the electroactivity of the fibrillar collagen-modified conducting polymer substrates. Rat pheochromocytoma (nerve) cells showed increased differentiation and neurite outgrowth on the fibrillar collagen, which was further enhanced through electrical stimulation of the underlying conducting polymer substrate. Our study demonstrates that the direct coupling of ECM components such as collagen, followed by their further self-assembly into 3-dimensional matrices, has the potential to improve the neural-electrode interface of implant electrodes by encouraging nerve cell attachment and differentiation.

  17. Dendritic ice morphology in unidirectionally solidified collagen suspensions

    NASA Astrophysics Data System (ADS)

    Schoof, H.; Bruns, L.; Fischer, A.; Heschel, I.; Rau, G.

    2000-01-01

    Collagen is a fibrillar protein which is commonly used as a biodegradable biomaterial. A typical application of such a biomaterial is a freeze-dried collagen sponge which is primarily used as a permanent skin replacement for the treatment of deep dermal burns. Especially to diminish scar formation caused by a severe loss of skin, it is necessary to induce a cell migration into the sponges and the regeneration of endogenous tissue within the sponges. Thereby, the three-dimensional structure and the pore sizes of the collagen sponges strongly influence the wound healing. In order to study this influence, the development of a process to manufacture collagen sponges with an adjustable and homogeneous three-dimensional structure is necessary. The porous structure of freeze-dried sponges corresponds to the ice crystal morphology after freezing. In order to form an adjustable and homogeneous ice morphology, the unidirectional solidification of collagen suspensions was investigated. All experiments were performed in a cryomicroscope according to the Bridgman technique. To induce a constitutional supercooling leading to the breakdown of the planar ice front and the formation of a stable dendritic ice crystal morphology (without side branches), the addition of solutes to the basic collagen suspension is required. We used acetic acid and ethanol as soluble additives, because they are suitable for medical application. The effects of the temperature gradient, the ice front velocity, and the solute concentration on the primary spacing and the dendrite sizes were examined. In order to find a simplified experimental system, acetic acid solutions without collagen were solidified under the same freezing conditions. Although the primary spacings and the dendrite sizes almost varied in the same range for solutions and suspensions, they were influenced in a different manner by the freezing parameters and the solute concentrations. Varying the aforementioned parameters the primary

  18. UV damage of collagen: insights from model collagen peptides.

    PubMed

    Jariashvili, Ketevan; Madhan, Balaraman; Brodsky, Barbara; Kuchava, Ana; Namicheishvili, Louisa; Metreveli, Nunu

    2012-03-01

    Fibrils of Type I collagen in the skin are exposed to ultraviolet (UV) light and there have been claims that collagen photo-degradation leads to wrinkles and may contribute to skin cancers. To understand the effects of UV radiation on collagen, Type I collagen solutions were exposed to the UV-C wavelength of 254 nm for defined lengths of time at 4°C. Circular dichroism (CD) experiments show that irradiation of collagen leads to high loss of triple helical content with a new lower thermal stability peak and SDS-gel electrophoresis indicates breakdown of collagen chains. To better define the effects of UV radiation on the collagen triple-helix, the studies were extended to peptides which model the collagen sequence and conformation. CD studies showed irradiation for days led to lower magnitudes of the triple-helix maximum at 225 nm and lower thermal stabilities for two peptides containing multiple Gly-Pro-Hyp triplets. In contrast, the highest radiation exposure led to little change in the T(m) values of (Gly-Pro-Pro)(10) and (Ala-Hyp-Gly)(10) , although (Gly-Pro-Pro)(10) did show a significant decrease in triple helix intensity. Mass spectroscopy indicated preferential cleavage sites within the peptides, and identification of some of the most susceptible sites of cleavage. The effect of radiation on these well defined peptides gives insight into the sequence and conformational specificity of photo-degradation of collagen.

  19. Heterogeneity of collagens in rabbit cornea: type VI collagen

    SciTech Connect

    Cintron, C.; Hong, B.S.

    1988-05-01

    Normal adult rabbit corneas were digested with 5% pepsin and their collagens extracted with acetic acid. Collagen extracts were fractionated by differential salt precipitation. The 2.5 M NaCl fraction was then redissolved with tris buffer and precipitated with sodium acetate. The precipitate contained a high-molecular-weight disulfide-bonded aggregate which, upon reduction with mercaptoethanol, was converted into three distinct polypeptides having molecular weights between 45 and 66 Kd. These physical characteristics, together with the susceptibility of these polypeptides to collagenase and their amino acid composition, identified the high molecular weight aggregate as type VI collagen. Corneas from neonate rabbits and adult corneas containing 2-week-old scars were organ cultured in the presence of (/sup 14/C) glycine to incorporate radiolabel into collagen. Tissues were digested with 0.02% pepsin and their collagens extracted with formic acid. The total radioactivity of the extracts and tissue residues was determined before the collagens were separated by SDS-polyacrylamide slab gel electrophoresis. Radioactive collagen polypeptides bands were then stained with Coomassie blue, processed for fluorography, and analyzed by densitometry. The results show that: (1) type VI collagen is synthesized by neonate corneas and healing adult corneas; (2) it is not readily solubilized from either corneal tissue by 0.02% pepsin digestion and formic acid extraction; and (3) the proportion of type VI collagen deposited in scar tissue is markedly lower than that found in neonate corneas.

  20. Heterogeneity of collagens in rabbit cornea: type III collagen

    SciTech Connect

    Cintron, C.; Hong, B.S.; Covington, H.I.; Macarak, E.J.

    1988-05-01

    Whole neonate rabbit corneas and adult corneas containing 2-week-old scars were incubated in the presence of (/sup 14/C) glycine. Radiolabeled collagen extracted from the corneas and scar tissue were analyzed by sodium dodecylsulfate/polyacrylamide gel electrophoresis and fluorography to determine the types and relative quantity of collagen polypeptides present and synthesized by these tissues. In addition to other collagen types, type III was found in both neonate cornea and scar tissue from adult cornea, albeit in relatively small quantities. Type III collagen in normal cornea was associated with the residue after pepsin digestion and formic acid extraction of the tissue, and the same type of collagen was extracted from scar tissue after similar treatment. Type III collagen-specific monoclonal antibody bound to developing normal corneas and healing adult tissue sections, as determined by immunofluorescence. Antibody binding was localized to the endothelium and growing Descemet's membrane in fetal and neonate corneas, and restricted to the most posterior region of the corneal scar tissue. Although monoclonal antibody to keratan sulfate, used as a marker for stromal fibroblasts, bound to most of the scar tissue, the antibody failed to bind to the posterior scar tissue positive for type III collagen. We conclude that endothelial cells from fetal and neonate rabbit cornea and endothelium-derived fibroblasts from healing wounds of adult cornea synthesize and deposit type III collagen. Moreover, this collagen appears to be incorporated into the growing Descemet's membrane of normal corneas and narrow posterior portion of the scar tissue.

  1. Elevated expression of type VII collagen in the skin of patients with systemic sclerosis. Regulation by transforming growth factor-beta.

    PubMed Central

    Rudnicka, L; Varga, J; Christiano, A M; Iozzo, R V; Jimenez, S A; Uitto, J

    1994-01-01

    A hallmark of systemic sclerosis (SSc) is the development of tissue fibrosis. Excessive production of several connective tissue components normally present in the dermis, including type I, III, V, and VI collagens as well as fibronectin and proteoglycans, is a consistent finding in the skin of SSc patients. Type VII collagen is a major constituent of anchoring fibrils, present in the skin at the dermal-epidermal basement membrane zone. TGF-beta has been shown to upregulate the expression of the type VII collagen gene. In this study, we assessed the expression of type VII collagen and TGF-beta in the skin of patients with SSc. Indirect immunofluorescence showed an abundance of type VII collagen in the patients' skin, including the dermis. Ultrastructural analysis of SSc skin revealed an abundance of fibrillar material, possibly representing type VII collagen. The increased expression of type VII collagen epitopes was accompanied by the elevated expression of immunodetectable TGF-beta 1 and TGF-beta 2. Dermal fibroblasts cultured from the affected individuals showed a statistically significant (P < 0.02) increase in the expression of type VII collagen at the mRNA level, as detected by reverse transcription-PCR with a mutated cDNA as an internal standard, and increased deposition of the protein as assessed by indirect immunofluorescence. Thus, type VII collagen is abundantly present in SSc patients' dermis, a location not characteristic of its normal distribution, and its aberrant expression may relate to the presence of TGF-beta in the same topographic distribution. The presence of type VII collagen in the dermis may contribute to the tightly bound and indurated appearance of the affected skin in SSc patients. Images PMID:7512991

  2. Histrelin Implant

    MedlinePlus

    ... implant (Supprelin LA) is used to treat central precocious puberty (CPP; a condition causing children to enter puberty too soon, resulting in faster than normal bone growth and development of sexual characteristics) in girls ...

  3. Penile Implants

    MedlinePlus

    ... placed inside the penis to allow men with erectile dysfunction (ED) to get an erection. Penile implants are ... complications and follow-up care. For most men, erectile dysfunction can be successfully treated with medications or use ...

  4. Cochlear implants.

    PubMed

    Connell, Sarah S; Balkany, Thomas J

    2006-08-01

    Cochlear implants are cost-effective auditory prostheses that safely provide a high-quality sensation of hearing to adults who are severely or profoundly deaf. In the past 5 years, progress has been made in hardware and software design, candidate selection, surgical techniques, device programming, education and rehabilitation,and, most importantly, outcomes. Cochlear implantation in the elderly is well tolerated and provides marked improvement in auditory performance and psychosocial functioning.

  5. The effect of tissue-engineered cartilage biomechanical and biochemical properties on its post-implantation mechanical behavior.

    PubMed

    Khoshgoftar, Mehdi; Wilson, Wouter; Ito, Keita; van Donkelaar, Corrinus C

    2013-01-01

    The insufficient load-bearing capacity of today's tissue-engineered (TE) cartilage limits its clinical application. Focus has been on engineering cartilage with enhanced mechanical stiffness by reproducing native biochemical compositions. More recently, depth dependency of the biochemical content and the collagen network architecture has gained interest. However, it is unknown whether the mechanical performance of TE cartilage would benefit more from higher content of biochemical compositions or from achieving an appropriate collagen organization. Furthermore, the relative synthesis rate of collagen and proteoglycans during the TE process may affect implant performance. Such insights would assist tissue engineers to focus on those aspects that are most important. The aim of the present study is therefore to elucidate the relative importance of implant ground substance stiffness, collagen content, and collagen architecture of the implant, as well as the synthesis rate of the biochemical constituents for the post-implantation mechanical behavior of the implant. We approach this by computing the post-implantation mechanical conditions using a composition-based fibril-reinforced poro-viscoelastic swelling model of the medial tibia plateau. Results show that adverse implant composition and ultrastructure may lead to post-implantation excessive mechanical loads, with collagen orientation being the most critical variable. In addition, we predict that a faster synthesis rate of proteoglycans compared to that of collagen during TE culture may result in excessive loads on collagen fibers post-implantation. This indicates that even with similar final contents, constructs may behave differently depending on their development. Considering these aspects may help to engineer TE cartilage implants with improved survival rates.

  6. Contraceptive implants.

    PubMed

    McDonald-Mosley, Raegan; Burke, Anne E

    2010-03-01

    Implantable contraception has been extensively used worldwide. Implants are one of the most effective and reversible methods of contraception available. These devices may be particularly appropriate for certain populations of women, including women who cannot use estrogen-containing contraception. Implants are safe for use by women with many chronic medical problems. The newest implant, Implanon (Organon International, Oss, The Netherlands), is the only device currently available in the United States and was approved in 2006. It is registered for 3 years of pregnancy prevention. Contraceptive implants have failure rates similar to tubal ligation, and yet they are readily reversible with a return to fertility within days of removal. Moreover, these contraceptive devices can be safely placed in the immediate postpartum period, ensuring good contraceptive coverage for women who may be at risk for an unintended pregnancy. Irregular bleeding is a common side effect for all progestin-only contraceptive implants. Preinsertion counseling should address possible side effects, and treatment may be offered to women who experience prolonged or frequent bleeding.

  7. Collagenous colitis: an unrecognised entity.

    PubMed Central

    Bogomoletz, W V; Adnet, J J; Birembaut, P; Feydy, P; Dupont, P

    1980-01-01

    A patient is reported with chronic abdominal pain, diarrhoea, and associated radiological and endoscopic abnormalities of the sigmoid colon. Light and electron microscopic study of colorectal mucosa showed abnormal collagenous thickening of the subepithelial basement membrane. The authors felt that the clinical and morphological features justified a diagnosis of collagenous colitis. Review of the literature suggested that collagenous colitis was still an unrecognised entity. Images Fig. 1 Fig. 2 Fig. 3 PMID:7380341

  8. Second harmonic generation in collagen

    NASA Astrophysics Data System (ADS)

    Reiser, Karen M.; Stoller, Patrick; Celliers, Peter; Rubenchik, Alexander; Bratton, Clay; Yankelevich, Diego

    2003-11-01

    Collagen possesses a strong second order nonlinear susceptibility; when it is irradiated with intense laser light, some of the reflected and transmitted light will have twice the frequency of the incident beam, a phenomenon known as second harmonic generation (SHG). Polarization modulation of an ultra-short pulse laser beam can be used to simultaneously measure collagen fiber orientation, SHG intensity, and a parameter related to the second order non-linear susceptibility. This technique has made it possible to discriminate among patterns of fibrillar orientation in many tissues. In the present study the role that organizational complexity plays in the relationship between nonlinear optical properties and collagen structure is investigated. As a component of tissues and organs, collagen"s structure and function is inextricably intertwined with that of the many other matrix components; to what extent do these noncollagenous components affect its nonlinear properties? To answer this, we investigated SHG in two different collagenous tissues, liver and cartilage; in addition we looked at the effect of progressive pathological changes in these tissues on SHG. At the other end of the spectrum, we studied collagen organized at the minimal level of complexity necessary for SHG detection: fibrils generated from solutions containing only a single type of collagen. Data obtained from these studies suggest that collagen"s strong nonlinear susceptibility, a property no other biologically significant macromolecule shares to the same degree, may serve as more than the basis of a novel imaging device for soft tissue. Collagen"s nonlinear optical properties in conjunction with its vast capacity for self-initiated conformational change--through self-assembly, site recognition, post-translational modification, and the like -make it an attractive candidate molecule for any of several demanding engineering applications, such as nanopatterning.

  9. Acellular Dermal Matrix as a Core Strut for Projection in Nipple Reconstruction: Approaches for Three Different Methods of Breast Reconstruction

    PubMed Central

    Park, Gui-Yong; Cho, Hee-Eun; Lee, Byung-Il; Park, Seung-Ha

    2016-01-01

    Background The objective of this paper was to describe a novel technique for improving the maintenance of nipple projection in primary nipple reconstruction by using acellular dermal matrix as a strut in one of three different configurations, according to the method of prior breast reconstruction. The struts were designed to best fill the different types of dead spaces in nipple reconstruction depending on the breast reconstruction method. Methods A total of 50 primary nipple reconstructions were performed between May 2012 and May 2015. The prior breast reconstruction methods were latissimus dorsi (LD) flap (28 cases), transverse rectus abdominis myocutaneous (TRAM) flap (10 cases), or tissue expander/implant (12 cases). The nipple reconstruction technique involved the use of local flaps, including the C-V flap or star flap. A 1×2-cm acellular dermal matrix was placed into the core with O-, I-, and L-shaped struts for prior LD, TRAM, and expander/implant methods, respectively. The projection of the reconstructed nipple was measured at the time of surgery and at 3, 6, and 9 months postoperatively. Results The nine-month average maintenance of nipple projection was 73.0%±9.67% for the LD flap group using an O-strut, 72.0%±11.53% for the TRAM flap group using an I-strut, and 69.0%±10.82% for the tissue expander/implant group using an L-strut. There were no cases of infection, wound dehiscence, or flap necrosis. Conclusions The application of an acellular dermal matrix with a different kind of strut for each of 3 breast reconstruction methods is an effective addition to current techniques for improving the maintenance of long-term projection in primary nipple reconstruction. PMID:27689049

  10. Role of NF-κB-p53 crosstalk in ultraviolet A-induced cell death and G1 arrest in human dermal fibroblasts.

    PubMed

    Lee, Yun Kyung; Cha, Hwa Jun; Hong, Misun; Yoon, Yeongmin; Lee, Hyunjin; An, Sungkwan

    2012-01-01

    Photoaging is the premature aging of the skin caused by repeated exposure to sunlight and is characterized by a depletion of the dermal extracellular matrix. This depletion is due to the loss of fibroblast cells and their multiple functions. UVA was revealed as a major inducer of photoaging in various clinical studies. As UVA photons have long wavelength spectra, UVA penetrates deeper into the dermis than UVB and UVC, leading to the induction of cell death, the destruction of the dermal extracellular matrix through the induction of matrix metalloproteinase expression, and the repression of collagen expression. However, the exact effects of UVA on the skin remain a matter of debate. Here, we assess cell cycle stage to demonstrate that NF-κB-p53 crosstalk induces apoptosis and growth arrest in UVA-irradiated human dermal fibroblasts. In addition, UVA irradiation led to an increase of NF-κB-HDAC1 complexes, which in turn repressed cyclin D1 expression in UVA-irradiated human dermal fibroblasts. We provide direct evidence that UVA irradiation induces changes in the p53-dependent NF-κB complex that lead to growth arrest and apoptosis through the repression of cyclin D1. These studies uncovered that NF-κB-p53 crosstalk is a key regulator of UVA-dependent growth arrest and apoptosis.

  11. Hair growth promoting effect of dermal papilla like tissues from canine adipose-derived mesenchymal stem cells through vascular endothelial growth factor

    PubMed Central

    LEE, Aeri; BAE, Sohee; LEE, Seung Hoon; KWEON, Oh-Kyeong; KIM, Wan Hee

    2016-01-01

    The purpose of this study was to investigate the protein expression pattern and the in vivo trichogenicity of dermal papilla-like tissues (DPLTs) made from canine adipose-derived mesenchymal stem cells (ASCs) in athymic nude mice. Canine ASCs were isolated and cultured from adipose tissue, and differentiation was induced by culturing ASCs in dermal papilla forming media. DPLTs were embedded in collagen gel, and their structural characteristics and protein expression were evaluated by hematoxylin and eosin stain and immunohistochemistry. Athymic nude mice were divided into two groups (control and DPLTs groups), and DPLTs were injected in skin wounds of mice in the DPLTs group. The trichogenicity of DPLTs was assessed by gross and histological evaluations for 30 days. The fate and the growth factor-secretion effect of DPLTs were evaluated by immunohistochemistry and Western blotting. DPLTs have a compact aggregated structure, form extracellular matrix and highly express the protein specific for dermal papillae, including ALP and versican. New hair follicle formation was remarkable in nude mice of the DPLTs group in gross findings and H&E stain. Vascularization was increased in the DPLTs group, which was the effect of vascular endothelial growth factor secreted by DPLTs in vitro and in vivo. These data suggest that engineered canine DPLTs have characteristics of dermal papillae and have a positive effect on hair regeneration by secreting growth factors. PMID:27647656

  12. Hypoxia drives the transition of human dermal fibroblasts to a myofibroblast-like phenotype via the TGF-β1/Smad3 pathway

    PubMed Central

    Zhao, Bin; Guan, Hao; Liu, Jia-Qi; Zheng, Zhao; Zhou, Qin; Zhang, Jian; Su, Lin-Lin; Hu, Da-Hai

    2017-01-01

    Keloids, partially considered as benign tumors, are characterized by the overgrowth of fibrosis beyond the boundaries of the wound and are regulated mainly by transforming growth factor (TGF)-β1, which induces the transition of fibroblasts to myofibroblasts. Hypoxia is an important driving force in the development of lung and liver fibrosis by activating hypoxia inducible factor-1α and stimulating epithelial-mesenchymal transition. However, it is unknown whether and hypoxia can influence human dermal scarring. The aim of this study was to investigate whether hypoxia drives the transition of dermal fibroblasts to myofibroblasts and to clarify the potential transduction mechanisms involved. First, we observed that keloids are a relatively hypoxic tissue. Second, we found that hypoxia drives the transition of normal dermal fibroblasts to a myofibroblast-like phenotype [high expression of α-smooth muscle actin (α-SMA) and collagen I and III]. Finally, hypoxia effectively facilitated the nuclear import of the Smad2 and Smad3 complex, while blockade with the Smad3 inhibitor, SIS3, significantly impaired the expression of hypoxia-induced fibrosis-related molecules. Taken together, to the best of our knowledge, this study demonstrates for the first time that hypoxia facilitates the transition of dermal fibroblasts to myofibroblasts through the activation of the TGF-β1/Smad3 signaling pathway and our findings may provide a potential target for the treatment of keloids. PMID:27909731

  13. Protecting effect of phytoncide solution, on normal human dermal fibroblasts against reactive oxygen species.

    PubMed

    Fujimori, Hiroaki; Hisama, Masayoshi; Shibayama, Hiroharu; Iwaki, Masahiro

    2009-01-01

    Four types of phytoncide solutions (A-Type, AB-Type, D-Type and G-Type) was evaluated for reduction of cell damage induced by oxidative stress, ultraviolet A (UVA), ultraviolet B (UVB), hydroxyperoxide (H2O2) and t-butyl-hydroperoxide (t-BHP); stimulation of collagen synthesis against UVA irradiation; and inhibition of matrix metalloproteinase-1 (MMP-1) activity induced by UVA in human normal dermal fibroblasts and human reconstituted skin model. The A-Type, AB-Type, D-Type and G-Type of phytoncide solutions pretreatment resulted in significant protection against cell damage induced by UVB, UVA, H2O2 and t-BHP. The amount of type I collagen following UVA irradiation was increased by treatment with phytoncide solutions in a concentration-dependent manner. On the other hand, phytoncide solutions also suppressed the excess MMP-1 irradiated UVA in a concentration-dependent manner. These effects of G-type solution were superior to those of other types solutions.

  14. Collagen alpha5 and alpha2(IV) chain coexpression: analysis of skin biopsies of Alport patients.

    PubMed

    Patey-Mariaud de Serre, N; Garfa, M; Bessiéres, B; Noël, L H; Knebelmann, B

    2007-08-01

    Alport syndrome is a collagen type IV disease caused by mutations in the COL4A5 gene with the X-linked form being most prevalent. The resultant alpha5(IV) collagen chain is a component of the glomerular and skin basement membranes (SBMs). Immunofluorescent determination of the alpha5(IV) chain in skin biopsies is the procedure of choice to identify patients. In 30% of patients, however, the mutant protein is still found in the SBM resulting in a normal staining pattern. In order to minimize or eliminate false results, we compared the distribution of the alpha2(IV) chain (another SBM component) and the alpha5(IV) chain by standard double label immunofluorescence (IF) and by confocal laser scanning microscopy. The study was performed on 55 skin biopsies of patients suspected of Alports and five normal control specimens. In normal skin, IF showed the classical linear pattern for both collagens along the basement membrane. Additionally, decreased alpha5(IV) was found in the bottom of the dermal papillary basement membrane. Confocal analysis confirmed the results and show alpha5(IV) focal interruptions. In suspected patients, both techniques showed the same rate of abnormal alpha5(IV) expression: segmental in women and absent in men. Our results show a physiological variation of alpha5(IV) location with focal interruptions and decreased expression in the bottom of the dermal basement membrane. Comparison of alpha5(IV) with alpha2(IV) expression is simple and eliminates technical artifacts.

  15. DREAM: a method for semi-quantitative dermal exposure assessment.

    PubMed

    Van-Wendel-de-Joode, Berna; Brouwer, Derk H; Vermeulen, Roel; Van Hemmen, Joop J; Heederik, Dick; Kromhout, Hans

    2003-01-01

    This paper describes a new method (DREAM) for structured, semi-quantitative dermal exposure assessment for chemical or biological agents that can be used in occupational hygiene or epidemiology. It is anticipated that DREAM could serve as an initial assessment of dermal exposure, amongst others, resulting in a ranking of tasks and subsequently jobs. DREAM consists of an inventory and evaluation part. Two examples of dermal exposure of workers of a car-construction company show that DREAM characterizes tasks and gives insight into exposure mechanisms, forming a basis for systematic exposure reduction. DREAM supplies estimates for exposure levels on the outside clothing layer as well as on skin, and provides insight into the distribution of dermal exposure over the body. Together with the ranking of tasks and people, this provides information for measurement strategies and helps to determine who, where and what to measure. In addition to dermal exposure assessment, the systematic description of dermal exposure pathways helps to prioritize and determine most adequate measurement strategies and methods. DREAM could be a promising approach for structured, semi-quantitative, dermal exposure assessment.

  16. Test in canine extraction site preservations by using mineralized collagen plug with or without membrane.

    PubMed

    Sun, Yi; Wang, Cheng-Yue; Wang, Zhi-Ying; Cui, Yun; Qiu, Zhi-Ye; Song, Tian-Xi; Cui, Fu-Zhai

    2016-04-01

    The aim of this study was to discuss the feasibility of porous mineralized collagen plug and bilayer mineralized collagen-guided bone regeneration membrane in site preservation in extraction sockets. The third mandibular premolars on both sides were extracted from four dogs, thus there were 16 alveolar sockets in all dogs and were randomly assigned into three groups. Group A had six alveolar sockets, and groups B and C had five alveolar sockets, respectively. Each alveolar socket of group A was immediately implanted with a porous mineralized collagen plug and covered with a bilayer mineralized collagen-guided bone regeneration membrane after tooth extraction. Alveolar sockets of group B were implanted with porous mineralized collagen plug only, and group C was set as blank control without any implantation. The healing effects of the extraction sockets were evaluated by gross observation, morphological measurements, and X-ray micro-computed tomography after twelve weeks. Twelve weeks after operation, both groups A and B had more amount of new bone formation compared with group C; in terms of the degree of alveolar bone height, group A was lower than groups B and C with significant differences; the bone mineral density in the region of interest and bone remodeling degree in group A were higher than those of groups B and C. As a result, porous mineralized collagen plug could induce the regeneration of new bone in extraction socket, and combined use of porous mineralized collagen plug and bilayer mineralized collagen guided bone regeneration membrane could further reduce the absorption of alveolar ridge and preserve the socket site.

  17. Dermal and Ophthalmic Findings in Pseudohypoaldosteronism

    PubMed Central

    Korkut, Sabriye; Gökalp, Emir; Özdemir, Ahmet; Kurtoğlu, Selim; Demirtaş, Şafak; Gül, Ülkü; Baştuğ, Osman

    2015-01-01

    Pseudohypoaldosteronism (PHA) is defined as a state of resistance to aldosterone, a hormone crucial for electrolyte equilibrium. The genetically transmitted type of PHA is primary hypoaldosteronism. Secondary hypoaldosteronism develops as a result of hydronephrosis or hydroureter. PHA patients suffer from severe hyponatremia and a severe clinical condition due to severe loss of salt can be encountered in the neonatal period. Dermal findings in the form of miliaria rubra can also develop in these patients. With the loss of salt, abnormal accumulation of sebum in the eye due to a defect in the sodium channels can also occur. In this paper, a case of PHA in a newborn showing typical dermatological and ophthalmological findings is presented. PMID:26316441

  18. Chemical chaperone treatment reduces intracellular accumulation of mutant collagen IV and ameliorates the cellular phenotype of a COL4A2 mutation that causes haemorrhagic stroke.

    PubMed

    Murray, Lydia S; Lu, Yinhui; Taggart, Aislynn; Van Regemorter, Nicole; Vilain, Catheline; Abramowicz, Marc; Kadler, Karl E; Van Agtmael, Tom

    2014-01-15

    Haemorrhagic stroke accounts for ∼20% of stroke cases and porencephaly is a clinical consequence of perinatal cerebral haemorrhaging. Here, we report the identification of a novel dominant G702D mutation in the collagen domain of COL4A2 (collagen IV alpha chain 2) in a family displaying porencephaly with reduced penetrance. COL4A2 is the obligatory protein partner of COL4A1 but in contrast to most COL4A1 mutations, the COL4A2 mutation does not lead to eye or kidney disease. Analysis of dermal biopsies from a patient and his unaffected father, who also carries the mutation, revealed that both display basement membrane (BM) defects. Intriguingly, defective collagen IV incorporation into the dermal BM was observed in the patient only and was associated with endoplasmic reticulum (ER) retention of COL4A2 in primary dermal fibroblasts. This intracellular accumulation led to ER stress, unfolded protein response activation, reduced cell proliferation and increased apoptosis. Interestingly, the absence of ER retention of COL4A2 and ER stress in cells from the unaffected father indicate that accumulation and/or clearance of mutant COL4A2 from the ER may be a critical modifier for disease development. Our analysis also revealed that mutant collagen IV is degraded via the proteasome. Importantly, treatment of patient cells with a chemical chaperone decreased intracellular COL4A2 levels, ER stress and apoptosis, demonstrating that reducing intracellular collagen accumulation can ameliorate the cellular phenotype of COL4A2 mutations. Importantly, these data highlight that manipulation of chaperone levels, intracellular collagen accumulation and ER stress are potential therapeutic options for collagen IV diseases including haemorrhagic stroke.

  19. Collagen XVII Shedding Suppresses Re-Epithelialization by Directing Keratinocyte Migration and Dampening mTOR Signaling.

    PubMed

    Jacków, Joanna; Löffek, Stefanie; Nyström, Alexander; Bruckner-Tuderman, Leena; Franzke, Claus-Werner

    2016-05-01

    Transmembrane collagen XVII is traditionally viewed as an important hemidesmosomal attachment component that promotes stable dermal-epidermal adhesion in the skin. However, its expression is highly elevated at the leading edges of cutaneous wounds or invasive carcinomas, suggesting alternative functions in cell migration. The collagenous ectodomain of collagen XVII is constitutively shed from the cell surface by a disintegrin and metalloproteinases, and this shedding is strongly induced during wound healing. Recently, we investigated the physiological relevance of collagen XVII shedding by generating knock-in mice, which exclusively express a functional non-sheddable collagen XVII mutant. Prevention of ectodomain shedding in these mice caused no spontaneous phenotype in resting skin, but accelerated re-epithelialization on skin wounding. Here, we investigated the mechanistic function of shedding during wound healing. Using the non-shedding collagen XVII mice as a model, we uncovered ectodomain shedding as a highly dynamic modulator of in vivo proliferation and motility of activated keratinocytes through tight coordination of α6β4 integrin-laminin-332 interactions and dampening of mechanistic target of rapamycin signaling at the wound edges. Thus, our studies identify ectodomain shedding of collagen XVII as an interactive platform that translates shedding into a signal for directed cell growth and motility during skin regeneration.

  20. Relationships between molecular mobility, fibrillogenesis of collagen molecules, and the inflammatory response: an experimental study in vitro and in vivo.

    PubMed

    Nam, Kwangwoo; Seo, Ji-Hun; Kimura, Tsuyoshi; Yui, Nobuhiko; Kishida, Akio

    2014-11-01

    This study was designed to investigate the in vitro adsorption and fibrillogenesis of collagen on a surface with dynamic properties and to investigate how this surface affected the inflammatory response in vivo. Investigation of collagen-surface interactions is directly related to the control of wound healing where collagen adsorption, fibrillization, deposition, and maturation occur. ABA-type block copolymers, composed of polyrotaxane (which possesses α-cyclodextrin threaded along poly(ethylene glycol)) and hydrophobic terminal segments, were used to prepare mobile surfaces with representative dynamic properties. Analyses using a quartz crystal microbalance with dissipation monitoring (QCM-D) indicated that increasing the mobility of the polymer on the surface led to the formation of a soft collagen layer. The collagens in this layer had rearranged, leading to the formation of thicker collagen fibrils by lateral aggregation. When a surface with a high molecular mobility was subcutaneously implanted into rats, collagen rearrangement occurred leading to suppression of macrophage recruitment at the interface and the formation of a fibrotic capsule around the implant. These results suggest that surface mobility on an implant is an important parameter for normal wound healing.

  1. The influence of vapor pressure of chemicals on dermal penetration.

    PubMed

    Gilpin, Sarah

    2014-01-01

    Dermal exposure is an important route of entry for chemicals in occupational and consumer settings. Key to this exposure is the penetration of the skin's barrier, and key to this penetration is a chemical's vapor pressure. Until now, vapor pressure and its effects on the skin have yet to be widely studied. This review aims to provide some historical background on early work on dermal penetration for volatile materials, which has helped form later research into the effects of vapor pressure on chemical risk assessment for dermal exposures. This review should be the start of an investigation into more in-depth coverage of vapor pressure and current prediction models.

  2. Human collagen Krox up-regulates type I collagen expression in normal and scleroderma fibroblasts through interaction with Sp1 and Sp3 transcription factors.

    PubMed

    Kypriotou, Magdalini; Beauchef, Gallic; Chadjichristos, Christos; Widom, Russell; Renard, Emmanuelle; Jimenez, Sergio A; Korn, Joseph; Maquart, François-Xavier; Oddos, Thierry; Von Stetten, Otto; Pujol, Jean-Pierre; Galéra, Philippe

    2007-11-02

    Despite several investigations, the transcriptional mechanisms that regulate the expression of both type I collagen genes (COL1A1 and COL1A2) in either physiological or pathological situations, such as scleroderma, are not completely known. We have investigated the role of hc-Krox transcription factor on type I collagen expression by human dermal fibroblasts. hc-Krox exerted a stimulating effect on type I collagen protein synthesis and enhanced the corresponding mRNA steady-state levels of COL1A1 and COL1A2 in foreskin fibroblasts (FF), adult normal fibroblasts (ANF), and scleroderma fibroblasts (SF). Forced hc-Krox expression was found to up-regulate COL1A1 transcription through a -112/-61-bp sequence in FF, ANF, and SF. Knockdown of hc-Krox by short interfering RNA and decoy strategies confirmed the transactivating effect of hc-Krox and decreased substantially COL1A1 transcription levels in all fibro-blast types. The -112/-61-bp sequence bound specifically hc-Krox but also Sp1 and CBF. Attempts to elucidate the potential interactions between hc-Krox, Sp1, and Sp3 revealed that all of them co-immunoprecipitate from FF cellular extracts when a c-Krox antibody was used and bind to the COL1A1 promoter in chromatin immunoprecipitation assays. Moreover, hc-Krox DNA binding activity to its COL1A1-responsive element is increased in SF, cells producing higher amounts of type I collagen compared with ANF and FF. These data suggest that the regulation of COL1A1 gene transcription in human dermal fibroblasts involves a complex machinery that implicates at least three transcription proteins, hc-Krox, Sp1, and Sp3, which could act in concert to up-regulate COL1A1 transcriptional activity and provide evidence for a pro-fibrotic role of hc-Krox.

  3. Biomechanical and molecular characteristics of hereditary equine regional dermal asthenia in Quarter Horses.

    PubMed

    Grady, Jesse G; Elder, Steven H; Ryan, Peter L; Swiderski, Cyprianna E; Rashmir-Raven, Ann M

    2009-10-01

    Hereditary equine regional dermal asthenia (HERDA) is an autosomal recessive skin disorder that has yet to be fully characterized. HERDA is predominately expressed in Quarter Horses, with the majority of these disseminating from elite cutting horse bloodlines, leading to the increased incidence of HERDA in recent years. Affected horses have loose, hyper-extensible, fragile skin and are frequently euthanized due to poor wound healing and disfiguring scars. This study sought to better characterize HERDA by analysis of the biomechanical parameters of tensile strength, modulus of elasticity, energy to failure and thickness of skin from 10 affected and 6 unaffected horses using an Instron Universal Testing Instrument. In addition, total soluble collagen and glycosaminoglycan concentrations of skin were analysed from 13 affected and 12 unaffected horses using Sircol Soluble Collagen and Blyscan Sulfated Glycosaminoglycan assays respectively. Affected horses exhibited a two to threefold reduction in tensile strength versus unaffected horses with statistically significant differences at six of seven sample locations (P < or = 0.05). The modulus of elasticity proved to be significantly different at six of seven sample locations, energy to failure at six of seven sample locations, and skin thickness at one of seven sample locations (P < or = 0.05). Affected horses exhibited significantly higher amounts of total soluble collagen than unaffected horses (P < or = 0.05). No significant difference was demonstrated between groups for glycosaminoglycan concentration. Affected horses demonstrated uniformly weaker skin across sample locations, indicating the biomechanical properties of HERDA are not regionally confined to specific areas of the horses' skin.

  4. In vivo quantification of human dermal skin aging using SHG and autofluorescence

    NASA Astrophysics Data System (ADS)

    Puschmann, Stefan; Rahn, Christian-Dennis; Wenck, Horst; Gallinat, Stefan; Fischer, Frank

    2012-03-01

    There are visible changes during skin aging. In the extracellular matrix these changes referred to as intrinsic aging (skin areas not exposed to sunlight) and extrinsic aging can be measured using various methods, such as subjective clinical evaluation, histology and molecular analysis. In this study we developed a new parameter for the non-invasive quantitative determination of dermal skin aging utilizing a five-dimensional intravital tomography (5D-IVT). This device, also known as 5D - multi-photon laser scanning microscopy, is a powerful tool to investigate (photo)aging-associated alterations in vivo. Structural alterations in the dermis of extrinsically aged (chronically sun-exposed) and intrinsically aged (sun-protected) human skin were recorded utilizing the collagen-specific second harmonic generation (SHG) signal and the elastin-specific autofluorescence (AF) signal. Recording took place in young and elderly volunteers. The resulting images were processed in order to gain the elastin percentage and the collagen percentage per image. Then, the elastin - to - collagen ratio (ELCOR) was calculated. With respect to volar forearm skin, the ELCOR significantly increased with age. In elderly volunteers, the ELCOR value calculated for the chronically sun-exposed temple area was significantly augmented compared with the sun-protected upper arm area. Based on 5D-IVT we introduce the ELCOR as a new means to quantify age-associated alterations in the extracellular matrix of in vivo human skin. This novel parameter is compared to the currently used "SHG to AF aging index" of the dermis (SAAID).

  5. Bog blueberry anthocyanins alleviate photoaging in ultraviolet-B irradiation-induced human dermal fibroblasts.

    PubMed

    Bae, Ji-Young; Lim, Soon Sung; Kim, Sun Ju; Choi, Jung-Suk; Park, Jinseu; Ju, Sung Mi; Han, Seoung Jun; Kang, Il-Jun; Kang, Young-Hee

    2009-06-01

    Fruits of bog blueberry (Vaccinium uliginosum L.) are rich in anthocyanins that contribute pigmentation. Anthocyanins have received much attention as agents with potentials preventing chronic diseases. This study investigated the capacity of anthocyanin-rich extract from bog blueberry (ATH-BBe) to inhibit photoaging in UV-B-irradiated human dermal fibroblasts. BBe anthocyanins were detected as cyanidin-3-glucoside, petunidin-3-glucoside, malvidin-3-glucoside, and delphinidin3-glucoside. ATH-BBe attenuated UV-B-induced toxicity accompanying reactive oxygen species (ROS) production and the resultant DNA damage responsible for activation of p53 and Bad. Preincubation of ATH-BBe markedly suppressed collagen degradation via blunting production of collagenolytic matrix metalloproteinases (MMP). Additionally, ATH-BBe enhanced UV-B-downregulated procollagen expression at transcriptional levels. We next attempted to explore whether ATH-BBe mitigated the MMP-promoted collagen degradation through blocking nuclear factor kappaB (NF-kappaB) activation and MAPK-signaling cascades. UV-B radiation enhanced nuclear translocation of NF-kappaB, which was reversed by treatment with ATH-BBe. The UV-B irradiation rapidly activated apoptosis signal-regulating kinase-1 (ASK-1)-signaling cascades of JNK and p38 mitogen-activated protein kinase (p38 MAPK), whereas ATH-BBe hampered phosphorylation of c-Jun, p53, and signal transducers and activators of transcription-1 (STAT-1) linked to these MAPK signaling pathways. ATH-BBe diminished UV-B augmented-release of inflammatory interleukin (IL)-6 and IL-8. These results demonstrate that ATH-BBe dampens UV-B-triggered collagen destruction and inflammatory responses through modulating NF-kappaB-responsive and MAPK-dependent pathways. Therefore, anthocyanins from edible bog blueberry may be protective against UV-induced skin photoaging.

  6. The effect of type II collagen on MSC osteogenic differentiation and bone defect repair.

    PubMed

    Chiu, Li-Hsuan; Lai, Wen-Fu T; Chang, Shwu-Fen; Wong, Chin-Chean; Fan, Cheng-Yu; Fang, Chia-Lang; Tsai, Yu-Hui

    2014-03-01

    The function of type II collagen in cartilage is well documented and its importance for long bone development has been implicated. However, the involvement of type II collagen in bone marrow derived mesenchymal stem cell (BMSC) osteogenesis has not been well investigated. This study elucidated the pivotal role of type II collagen in BMSC osteogenesis and its potential application to bone healing. Type II collagen-coated surface was found to accelerate calcium deposition, and the interaction of osteogenic medium-induced BMSCs with type II collagen-coated surface was mainly mediated through integrin α2β1. Exogenous type II collagen directly activated FAK-JNK signaling and resulted in the phosphorylation of RUNX2. In a segmental defect model in rats, type II collagen-HA/TCP-implanted rats showed significant callus formation at the reunion site, and a higher SFI (sciatic function index) scoring as comparing to other groups were also observed at 7, 14, and 21 day post-surgery. Collectively, type II collagen serves as a better modulator during early osteogenic differentiation of BMSCs by facilitating RUNX2 activation through integrin α2β1-FAK-JNK signaling axis, and enhance bone defect repair through an endochondral ossification-like process. These results advance our understanding about the cartilaginous ECM-BMSC interaction, and provide perspective for bone defect repair strategies.

  7. Transformation of amorphous calcium carbonate to rod-like single crystal calcite via "copying" collagen template.

    PubMed

    Xue, Zhonghui; Hu, Binbin; Dai, Shuxi; Du, Zuliang

    2015-10-01

    Collagen Langmuir films were prepared by spreading the solution of collagen over deionized water, CaCl2 solution and Ca(HCO3)2 solution. Resultant collagen Langmuir monolayers were then compressed to a lateral pressure of 10 mN/m and held there for different duration, allowing the crystallization of CaCO3. The effect of crystallization time on the phase composition and microstructure of CaCO3 was investigated. It was found that amorphous calcium carbonate (ACC) was obtained at a crystallization time of 6 h. The amorphous CaCO3 was transformed to rod-like single crystal calcite crystals at an extended crystallization time of 12 h and 24 h, via "copying" the symmetry and dimensionalities of collagen fibers. Resultant calcite crystallites were well oriented along the longitudinal axis of collagen fibers. The ordered surface structure of collagen fibers and electrostatic interactions played key roles in tuning the oriented nucleation and growth of the calcite crystallites. The mineralized collagen possessing both desired mechanical properties of collagen fiber and good biocompatibility of calcium carbonate may be assembled into an ideal biomaterial for bone implants.

  8. Factors that influence transgene expression and cell viability on DNA-PEI-seeded collagen films.

    PubMed

    Katz, Jordan M; Roth, Charles M; Dunn, Michael G

    2005-01-01

    Gene delivery from tissue-engineering devices has the potential to improve healing, but better regulation of the level and duration of gene expression is needed. We hypothesized that transgene expression could be controlled by varying the fabrication and soaking parameters used in making collagen- based gene delivery scaffolds. Collagen films were made from acid-insoluble type I bovine dermal collagen and seeded with plasmid DNA encoding firefly luciferase, complexed with polyethylenimine. By varying the thickness of the films, the volume of the DNA soak solution, and the pH of the DNA soak solution, and by cross-linking the films, we identified variable combinations that produce significantly different levels of cell number and transgene expression in L-929 cells in vitro. Increasing film thickness or soak volume increased overall reporter gene expression. Decreasing film thickness or soak volume decreased cell number but did not significantly change reporter gene expression per cell. Cross-linking by ultraviolet irradiation (before adding the DNA) significantly decreased transgene expression, probably because of decreased swelling of the collagen film. These results suggest that collagen-based biomaterials may be designed and fabricated to induce, in a controlled fashion, various levels of cellularity and transgene expression.

  9. Collagen Unfolding Accelerates Water Influx, Determining Hydration in the Interstitial Matrix

    PubMed Central

    McGee, Maria P.; Morykwas, Michael; Shelton, Julie; Argenta, Louis

    2012-01-01

    In the interstitial matrix, collagen unfolding at physiologic temperatures is thought to facilitate interactions with enzymes and scaffold molecules during inflammation, tissue remodeling, and wound healing. We tested the hypothesis that it also plays a role in modulating flows and matrix hydration potential. After progressively unfolding dermal collagen in situ, we measured the hydration parameters by osmotic stress techniques and modeled them as linear functions of unfolded collagen, quantified by differential scanning calorimetry after timed heat treatment. Consistent with the hypothetical model, the thermodynamic and flow parameters obtained experimentally were related linearly to the unfolded collagen fraction. The increases in relative humidity and intensity of T2 maps were also consistent with interfacial energy contributions to the hydration potential and the hydrophobic character of the newly formed protein/water interfaces. As a plausible explanation, we propose that increased tension at interfaces formed during collagen unfolding generate local gradients in the matrix that accelerate water transfer in the dermis. This mechanism adds a convective component to interstitial transfer of biological fluids that, unlike diffusion, can speed the dispersion of water and large solutes within the matrix. PMID:23200049

  10. Effects of plant sterols derived from Aloe vera gel on human dermal fibroblasts in vitro and on skin condition in Japanese women

    PubMed Central

    Tanaka, Miyuki; Misawa, Eriko; Yamauchi, Koji; Abe, Fumiaki; Ishizaki, Chiaki

    2015-01-01

    Background Aloe is known for its topical use for treating wounds and burns. Many previous studies reported the healing effects of Aloe vera. However, there are few clinical studies on the effect of orally administered A. vera gel on the skin. Aloe sterols are a type of plant sterols that have the capability to regulate the metabolism of glucose and lipids. In a recent study, we confirmed that ingested Aloe sterols reached the peripheral tissues through the bloodstream. However, their influence on dermal fibroblasts has not been investigated. Methods First, we investigated the capability of Aloe sterols (cycloartenol and lophenol) to stimulate human dermal fibroblasts in vitro. Then, we investigated the effect of intake of Aloe vera gel powder (AVGP) containing 40 μg Aloe sterols on the skin conditions in Japanese women with dry skin in a randomized, double-blind, placebo-controlled trial. Results After cocultivation with Aloe sterols, the production of collagen and hyaluronic acid increased by approximately two-fold and 1.5-fold, and gene expression levels of these enzymes responsible for their synthesis were also observed in human dermal fibroblasts. An increase in arm skin hydration was observed at 8 weeks in the AVGP group, whereas a slight decrease in arm skin hydration was noted in the placebo group. However, there was no statistical difference between AVGP and placebo groups in skin moisture. In subgroup analysis, the change in the mean wrinkle depth was significantly lower in the AVGP group than in the control group. In addition, percent body fat after 8 weeks was significantly lower in the AVGP group. No AVGP intake-dependent harmful phenomenon was observed during the intake period. Conclusion The present study confirms that daily oral Aloe sterol-containing AVGP significantly reduced facial wrinkles in women aged ≥40 years, and Aloe sterols stimulate collagen and hyaluronic acid production by human dermal fibroblasts. PMID:25759593

  11. Alternatives to Acellular Dermal Matrix: Utilization of a Gore DualMesh Sling as a Cost-Conscious Adjunct for Breast Reconstruction

    PubMed Central

    Butterworth, James; Petty, Paul

    2017-01-01

    Objective: This study seeks an alternative to acellular dermal matrix in 2-staged breast reconstruction while minimizing cost. It was hypothesized that use of a Gore DualMesh would allow for similar intraoperative tissue expander fill volumes, time to second-stage reconstruction, and number of postoperative fills compared with acellular dermal matrix at only a fraction of the expense. Methods: Retrospective analysis comparing Gore DualMesh (59 breasts, 34 patients), acellular dermal matrix (13 breasts, 8 patients), and total muscle coverage (25 breasts, 14 patients) for postmastectomy breast reconstruction was performed. Time to second-stage reconstruction, number of expansions, and relative initial fill volumes were compared between the 3 groups. Secondarily, complication rates were also considered, including seroma, infection, expander/implant explantation, removal of mesh, and capsular contracture. Statistical analysis was performed utilizing the Fisher exact test and the χ2 test for categorical variables and the Mann-Whitney U test for continuous variables. Results: Relative initial fill volumes, number of expansions, and time to second-stage reconstruction showed no statistical difference between the acellular dermal matrix and Gore DualMesh groups (P = .494, P = .146, and P = .539, respectively). Furthermore, the Gore DualMesh group underwent significantly fewer fills (P < .001) and had a higher relative initial fill volume (P < .001) than the total muscle coverage group. The additional cost per breast as a result of including DualMesh was on average $385 versus $4287 for acellular dermal matrix. Complication rates were similar between all 3 groups without statistically significant differences. Conclusions: Gore DualMesh represents a safe alternative to acellular dermal matrix for breast reconstruction with similar aesthetic results in certain patients at a fraction of the cost. PMID:28261372

  12. Osteopontin (OPN) is an important protein to mediate improvements in the biocompatibility of C ion-implanted silicone rubber.

    PubMed

    Wang, Shao-liang; Shi, Xiao-hua; Yang, Zhi; Zhang, Yi-ming; Shen, Li-ru; Lei, Ze-yuan; Zhang, Zhi-Qing; Cao, Cong; Fan, Dong-li

    2014-01-01

    Medical device implants are drawing increasing amounts of interest from modern medical practitioners. However, this attention is not evenly spread across all such devices; most of these implantable devices can cause adverse reactions such as inflammation, fibrosis, thrombosis, and infection. In this work, the biocompatibility of silicone rubber (SR) was improved through carbon (C) ion implantation. Scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) results confirmed that these newly generated carbon-implanted silicone rubbers (C-SRs) had large, irregular peaks and deep valleys on their surfaces. The water contact angle of the SR surface decreased significantly after C ion implantation. C ion implantation also changed the surface charge distribution, silicone oxygen rate, and chemical-element distribution of SR to favor cell attachment. The dermal fibroblasts cultured on the surface C-SR grew faster and showed more typical fibroblastic shapes. The expression levels of major adhesion proteins, including talin-1, zyxin, and vinculin, were significantly higher in dermal fibroblasts cultured on C-SR coated plates than in dermal fibroblasts cultured on SR. Those same dermal fibroblasts on C-SRs showed more pronounced adhesion and migration abilities. Osteopontin (OPN), a critical extracellular matrix (ECM) protein, was up-regulated and secreted from dermal fibroblasts cultured on C-SR. Matrix metalloproteinase-9 (MMP-9) activity was also increased. These cells were highly mobile and were able to adhere to surfaces, but these abilities were inhibited by the monoclonal antibody against OPN, or by shRNA-mediated MMP-9 knockdown. Together, these results suggest that C ion implantation significantly improves SR biocompatibility, and that OPN is important to promote cell adhesion to the C-SR surface.

  13. Osteopontin (OPN) Is an Important Protein to Mediate Improvements in the Biocompatibility of C Ion-Implanted Silicone Rubber

    PubMed Central

    Zhang, Yi-ming; Shen, Li-ru; Lei, Ze-yuan; Zhang, Zhi-qing; Cao, Cong; Fan, Dong-li

    2014-01-01

    Medical device implants are drawing increasing amounts of interest from modern medical practitioners. However, this attention is not evenly spread across all such devices; most of these implantable devices can cause adverse reactions such as inflammation, fibrosis, thrombosis, and infection. In this work, the biocompatibility of silicone rubber (SR) was improved through carbon (C) ion implantation. Scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) results confirmed that these newly generated carbon-implanted silicone rubbers (C-SRs) had large, irregular peaks and deep valleys on their surfaces. The water contact angle of the SR surface decreased significantly after C ion implantation. C ion implantation also changed the surface charge distribution, silicone oxygen rate, and chemical-element distribution of SR to favor cell attachment. The dermal fibroblasts cultured on the surface C-SR grew faster and showed more typical fibroblastic shapes. The expression levels of major adhesion proteins, including talin-1, zyxin, and vinculin, were significantly higher in dermal fibroblasts cultured on C-SR coated plates than in dermal fibroblasts cultured on SR. Those same dermal fibroblasts on C-SRs showed more pronounced adhesion and migration abilities. Osteopontin (OPN), a critical extracellular matrix (ECM) protein, was up-regulated and secreted from dermal fibroblasts cultured on C-SR. Matrix metalloproteinase-9 (MMP-9) activity was also increased. These cells were highly mobile and were able to adhere to surfaces, but these abilities were inhibited by the monoclonal antibody against OPN, or by shRNA-mediated MMP-9 knockdown. Together, these results suggest that C ion implantation significantly improves SR biocompatibility, and that OPN is important to promote cell adhesion to the C-SR surface. PMID:24911051

  14. Is Sterile Better Than Aseptic? Comparing the Microbiology of Acellular Dermal Matrices

    PubMed Central

    Klein, Gabriel M.; Nasser, Ahmed E.; Phillips, Brett T.; Gersch, Robert P.; Fourman, Mitchell S.; Lilo, Sarit E.; Fritz, Jason R.; Khan, Sami U.; Dagum, Alexander B.

    2016-01-01

    Introduction: Postoperative infections are a major complication associated with tissue-expander-based breast reconstruction. The use of acellular dermal matrix (ADM) in this surgery has been identified as a potential reservoir of infection, prompting the development of sterile ADM. Although aseptic and sterile ADMs have been investigated, no study has focused on the occurrence and clinical outcome of bacterial colonization before implantation. Methods: Samples of aseptic AlloDerm, sterile Ready-To-Use AlloDerm, and AlloMax were taken before implantation. These samples were incubated in Tryptic soy broth overnight before being streaked on Trypticase soy agar, MacConkey agar, and 5% blood agar plates for culture and incubated for 48 hours. Culture results were cross-referenced with patient outcomes for 1 year postoperatively. Results: A total of 92 samples of ADM were collected from 63 patients. There were 15 cases of postoperative surgical site infection (16.3%). Only 1 sample of ADM (AlloMax) showed growth of Escherichia coli, which was likely a result of contamination. That patient did not develop any infectious sequelae. Patient outcomes showed no difference in the incidence of seroma or infection between sterile and aseptic ADMs. Conclusions: This study evaluates the microbiology of acellular dermal matrices before use in breast reconstruction. No difference was found in the preoperative bacterial load of either aseptic or sterile ADM. No significant difference was noted in infection or seroma formation. Given these results, we believe aseptic processing used on ADMs is equivalent to sterile processing in our patient cohort in terms of clinical infection and seroma occurrence postoperatively. PMID:27482500

  15. Direct inhibition of elastase and matrixmetalloproteinases and stimulation of biosynthesis of fibrillar collagens, elastin, and fibrillins by xanthohumol.

    PubMed

    Philips, Neena; Samuel, Mathew; Arena, Rosemarie; Chen, Yu-Jun; Conte, Jennifer; Natarajan, Prashanthi; Natrajan, Prashanti; Haas, Gerhard; Gonzalez, Salvador

    2010-01-01

    In skin aging there is deterioration of the extracellular matrix's collagen and elastin fibers, from its reduced biosynthesis and increased degradation by elastase and matrixmetalloproteinases (MMPs). Xanthohumol is a flavonoid isolated from the hop plant Humulus lupulus L., with anti-microbial, antioxidant, anti-inflammatory, and anti-carcinogenic properties. The goal of this research was to investigate xanthohumol as an anti-skinaging agent via its beneficial regulation of the extracellular matrix. To this purpose, we examined the direct effect of xanthohumol on the activities of elastase and MMPs (MMPs 1, 2, and 9) and its effect on the expression (protein and/or transcription levels) of collagens (types I, III, and V), elastin, and fibrillins (1 and 2) in dermal fibroblasts. Xanthohumol significantly inhibited elastase and MMP-9 activities from its lowest concentration, and MMP-1 and MMP-2 at its higher concentrations, which implies a greater protective effect on elastin. It dramatically increased the expression of types I, III, and V collagens, and elastin, fibrillin-1, and fibrillin-2 in dermal fibroblasts. The effects were similar to those of ascorbic acid. This is the first report identifying xanthohumol's potential to improve skin structure and firmness: it simultaneously inhibits the activities of elastase/MMPs and stimulates the biosynthesis of fibrillar collagens, elastin, and fibrillins.

  16. Ability of transplanted cultured epithelium to respond to dermal papillae.

    PubMed

    Xing, L; Kobayashi, K

    2001-10-01

    Cultured epithelium has been used successfully in the treatment of extensive burns. Regenerated epidermis, however, lacks such as hair follicles and sweat glands that are common in mammalian skin. We attempted to determine whether cultured epithelium could be induced to form hair follicles by dermal papillae, which are most important for the morphogenesis and growth of hair follicles. We cultivated adult rat sole keratinocytes, obtained the cultured epithelium, and prepared recombinants consisting of cultured epithelium and fresh dermal papillae with or without the sole dermis. These recombinants were then transplanted underneath the dermis of the dorsal skin of syngeneic rats or athymic mice. Histologic examination revealed that the transplanted cultured epithelium formed the follicular structures with sebaceous gland-like structure following induction of the dermal papillae, especially when supported by the dermis. We concluded that transplanted cultured epithelium of adult rat sole keratinocytes can respond to growth signals from adult dermal papillae.

  17. Engineering 3D Cellularized Collagen Gels for Vascular Tissue Regeneration.

    PubMed

    Meghezi, Sébastien; Seifu, Dawit G; Bono, Nina; Unsworth, Larry; Mequanint, Kibret; Mantovani, Diego

    2015-06-16

    Synthetic materials are known to initiate clinical complications such as inflammation, stenosis, and infections when implanted as vascular substitutes. Collagen has been extensively used for a wide range of biomedical applications and is considered a valid alternative to synthetic materials due to its inherent biocompatibility (i.e., low antigenicity, inflammation, and cytotoxic responses). However, the limited mechanical properties and the related low hand-ability of collagen gels have hampered their use as scaffold materials for vascular tissue engineering. Therefore, the rationale behind this work was first to engineer cellularized collagen gels into a tubular-shaped geometry and second to enhance smooth muscle cells driven reorganization of collagen matrix to obtain tissues stiff enough to be handled. The strategy described here is based on the direct assembling of collagen and smooth muscle cells (construct) in a 3D cylindrical geometry with the use of a molding technique. This process requires a maturation period, during which the constructs are cultured in a bioreactor under static conditions (without applied external dynamic mechanical constraints) for 1 or 2 weeks. The "static bioreactor" provides a monitored and controlled sterile environment (pH, temperature, gas exchange, nutrient supply and waste removal) to the constructs. During culture period, thickness measurements were performed to evaluate the cells-driven remodeling of the collagen matrix, and glucose consumption and lactate production rates were measured to monitor the cells metabolic activity. Finally, mechanical and viscoelastic properties were assessed for the resulting tubular constructs. To this end, specific protocols and a focused know-how (manipulation, gripping, working in hydrated environment, and so on) were developed to characterize the engineered tissues.

  18. Evaluation of nanoarchitectured collagen type II molecules on cartilage engineering.

    PubMed

    Kuo, Shyh Ming; Chiang, Ming Yu; Lan, Cheng Wen; Niu, Gregory Cheng-Chie; Chang, Shwu Jen

    2013-02-01

    Scaffold architecture, including the geometry and dimension of scaffolds, is an important parameter in cell adhesion, migration, proliferation, and differentiation. Following the characterization of collagen type II nanoarchitectured molecules, collagen fibrils (CNFs) and collagen spheres (CNPs) prepared using a high-voltage electric field in our laboratory, we proposed to use these nanoarchitectured molecules to assess their influence on the culturing of chondrocytes in stirred bioreactors. The results demonstrate that chondrocytes rapidly formed more and larger chondrocyte pellets (spheroids) after the addition of nanoarchitectured molecules into the culture medium. The maintenance of chondrocytes with round morphology and increased glycosaminoglycan secretion indicated that these spheroids contained viable and un-dedifferentiated chondrocytes. No significant increases in DNA content were detected. These results show that the introduction of these molecules did not affect chondrocyte proliferation during a 3-day culture period. After the addition of CNPs and CNFs into the culture medium, the expression levels of collagen type II and aggrecan genes in chondrocytes increased significantly as demonstrated by real-time PCR analysis. Interestingly, chondrocytes exhibited distinct collagen type II and aggrecan gene expression profiles in culture with CNPs and CNFs. The aggrecan gene expression level of the chondrocytes was 2.5-fold greater following CFN addition than following the addition of CNPs. In contrast, the collagen type II expression level of the chondrocytes was 2.2-fold greater following the addition of CNPs than following the addition of CNFs. The chondrocyte pellets rapidly restored defects in articular cartilage during a 1-month implantation period in a rabbit model.

  19. Acquired ichthyosis and impaired dermal lipogenesis in Hodgkin's disease.

    PubMed

    Cooper, M F; Wilson, P D; Hartop, P J; Shuster, S

    1980-06-01

    Epidermal lipid biosynthesis was normal in patients with mild ichthyosis due to Hodgkin's disease, but greatly reduced in one patient with severe ichthyosis. Dermal (sebaceous) lipid synthesis was decreased in all patients with Hodgkin's disease, whether or not they had ichthyosis, and was greatly reduced in the patient with severe ichthyosis. Neither the mechanism nor the possible relationship between the dermal and epidermal changes is understood.

  20. Dermal exposure and urinary 1-hydroxypyrene among asphalt roofing workers

    SciTech Connect

    McClean, M.D.; Rinehart, R.D.; Sapkota, A.; Cavallari, J.M.; Herrick, R.F.

    2007-07-01

    The primary objective of this study was to identify significant determinants of dermal exposure to polycyclic aromatic compounds (PACs) among asphalt roofing workers and use urinary 1-hydroxyprene (1-OHP) measurements to evaluate the effect of dermal exposure on total absorbed dose. The study population included 26 asphalt roofing workers who performed three primary tasks: tearing off old roofs, putting down new roofs, and operating the kettle at ground level. During multiple consecutive work shifts, dermal patch samples were collected from the underside of each worker's wrists and were analyzed for PACs, pyrene, and benzo(a)pyrene (BAP). During the same work week, urine samples were collected at pre-shift, post-shift, and bedtime each day and were analyzed for 1-OHP (205 urine samples). Linear mixed effects models were used to evaluate the dermal measurements for the purpose of identifying important determinants of exposure, and to evaluate urinary 1-OHP measurements for the purpose of identifying important determinants of total absorbed dose. Dermal exposures to PAC, pyrene, and BAP were found to vary significantly by roofing task and by the presence of an old coal tar pitch roof. For each of the three analytes, the adjusted mean dermal exposures associated with tear-off were approximately four times higher than exposures associated with operating the kettle. Exposure to coal tar pitch was associated with a 6-fold increase in PAC exposure, an 8-fold increase in pyrene exposure and a 35-fold increase in BAP exposure. The presence of coal tar pitch was the primary determinant of dermal exposure, particularly for exposure to BAP. However, the task-based differences that were observed while controlling for pitch suggest that exposure to asphalt also contributes to dermal exposures.

  1. Early dermabrasion of deep dermal burns with sandpaper. Case reports.

    PubMed

    Floccard, B; Tixier, F; Chatot-Henry, D; Lacotte, B; Mehdaoui, H; Drault, J N

    1998-12-01

    Deep dermal burns are initially difficult to evaluate, and they sometimes heal spontaneously. We present our experience of dermabrasion with sandpaper in four patients. It is a useful alternative to early excision of the scar. Skin grafts are not always required and the aesthetic results are excellent. Dermabrasion should be considered routinely for all deep dermal burns and particularly for facial burns and those caused by scalds.

  2. Dermal schwannoma (neurilemmoma): a peculiar foreign body reaction?

    PubMed

    Kneitz, Hermann; Weyandt, Gerhard; Meissner, Christoph; Gebhart, Edith; Bröcker, Eva B

    2010-06-01

    Schwannoma is usually a subcutaneous benign neoplasm that derives from nerve sheath. Pain and neurologic symptoms are uncommon, and exclusively dermal tumors are very rare. Solitary schwannoma has a traumatic origin in some cases, and rarely occur as a part of neurofibromatosis or schwannomatosis. An association of deeply located schwannoma with foreign material has been reported in very few cases. To our knowledge, we present the first case of a painful dermal schwannoma in association to foreign material.

  3. Type I Collagen and Collagen Mimetics as Angiogenesis Promoting Superpolymers

    SciTech Connect

    Twardowski, T.; Fertala, A.; Orgel, J.P.R.O.; San Antonio, J.D.

    2008-07-18

    Angiogenesis, the development of blood vessels from the pre-existing vasculature, is a key component of embryogenesis and tissue regeneration. Angiogenesis also drives pathologies such as tumor growth and metastasis, and hemangioma development in newborns. On the other hand, promotion of angiogenesis is needed in tissues with vascular insufficiencies, and in bioengineering, to endow tissue substitutes with appropriate microvasculatures. Therefore, much research has focused on defining mechanisms of angiogenesis, and identifying pro- and anti-angiogenic molecules. Type I collagen, the most abundant protein in humans, potently stimulates angiogenesis in vitro and in vivo. Crucial to its angiogenic activity appears to be ligation and possibly clustering of endothelial cell (EC) surface {alpha}1{beta}1/{alpha}2{beta}1 integrin receptors by the GFPGER502-507 sequence of the collagen fibril. However, additional aspects of collagen structure and function that may modulate its angiogenic properties are discussed. Moreover, type I collagen and fibrin, another angiogenic polymer, share several structural features. These observations suggest strategies for creating 'angiogenic superpolymers', including: modifying type I collagen to influence its biological half-life, immunogenicity, and integrin binding capacity; genetically engineering fibrillar collagens to include additional integrin binding sites or angiogenic determinants, and remove unnecessary or deleterious sequences without compromising fibril integrity; and exploring the suitability of poly(ortho ester), PEG-lysine copolymer, tubulin, and cholesteric cuticle as collagen mimetics, and suggesting means of modifying them to display ideal angiogenic properties. The collagenous and collagen mimetic angiogenic superpolymers described here may someday prove useful for many applications in tissue engineering and human medicine.

  4. Dermal mast cell responses in Paragonimus westermani-infected mice.

    PubMed

    Shin, M H

    1997-12-01

    This study was carried out to determine whether dermal mast cell responses to Paragonimus westermani in an abnormal host, the mouse, were dependent on the site of metacercarial inoculation. In mice during subcutaneous infection, the number of dermal mast cells were increased significantly (p < 0.05) at the first week (38.3/mm2) and then persisted at a high level until the sixth week (45.2/mm2) of infection compared with PBS-injected (control) mice (range: 19.4-25.1/mm2). In mice during oral infection, the number of dermal mast cells were increased significantly (p < 0.05) at two weeks (33.5/mm2) after infection and remained at these levels thereafter compared with non-infected (control) mice (range: 17.4-22.3/mm2). In mice both during subcutaneous and oral infection, the recruited dermal mast cells showed extensive degranulation at the second week (68.4% and 60.7%, respectively), reached a peak at the third week (81.4%, and 92.1%, respectively) and then declined slightly thereafter. By contrast, in both control mice, about 10% of dermal mast cells were degranulated. In conclusion, this study suggests that dermal mast cell responses to P. westermani in mice are dependent on cutaneous sensitization by larval excretory-secretory antigens, irrespective of infection route.

  5. Cochlear Implants

    MedlinePlus

    ... outside of the body, behind the ear. A second part is surgically placed under the skin. An implant does not restore normal hearing. It can help a person understand speech. Children and adults can benefit from them. National Institute on Deafness and Other Communication Disorders

  6. Implantable arterial grafts from human fibroblasts and fibrin using a multi-graft pulsed flow-stretch bioreactor with noninvasive strength monitoring

    PubMed Central

    Syedain, Zeeshan H.; Meier, Lee A.; Bjork, Jason W.; Lee, Ann; Tranquillo, Robert T.

    2011-01-01

    Tissue-engineered arteries based on entrapment of human dermal fibroblasts in fibrin gel yield completely biological vascular grafts that possess circumferential alignment characteristic of native arteries and essential to their mechanical properties. A bioreactor was developed to condition six grafts in the same culture medium while being subjected to similar cyclic distension and transmural flow resulting from pulsed flow distributed among the graft lumens via a manifold. The lumenal pressure and circumferential stretch were noninvasively monitored and used to calculate stiffness in the range of 80-120 mmHg and then to successfully predict graft burst strength. The length of the graft was incrementally shortened during bioreactor culture to maintain circumferential alignment and achieve mechanical anisotropy comparable to native arteries. After 7-9 weeks of bioreactor culture, the fibrin-based grafts were extensively remodeled by the fibroblasts into circumferentially-aligned tubes of collagen and other extracellular matrix with burst pressures in the range of 1400-1600 mmHg and compliance comparable to native arteries. The tissue suture retention force was also suitable for implantation in the rat model and, with poly(lactic acid) sewing rings entrapped at both ends of the graft, also in the ovine model. The strength achieved with a biological scaffold in such a short duration is unprecedented for an engineered artery. PMID:20934214

  7. Topical all-trans retinoic acid stimulates collagen synthesis in vivo.

    PubMed

    Schwartz, E; Cruickshank, F A; Mezick, J A; Kligman, L H

    1991-06-01

    Histochemical and ultrastructural studies demonstrate that topical all-trans retinoic acid (RA) stimulates the deposition of a subepidermal band of collagen in photoaged hairless mice. The aim of this study was to examine the effect of RA treatment on collagen synthesis using biochemical and immunochemical techniques. Albino hairless mice were irradiated three times a week for 10 weeks with four minimal erythema doses of UVB from Westinghouse FS-40 bulbs. In the post-UV period, mice were either nontreated or treated with 0.05% RA or the ethanol-propylene glycol vehicle for up to 10 weeks. Antibodies against the aminopropeptide (AP) of type III procollagen were used in immunofluorescence microscopy and radioimmunoassay techniques. The AP of type III collagen is normally present throughout the dermis and in areas of active collagen synthesis (i.e., the dermal-epidermal junction). In this study, a similar distribution was seen in all untreated and vehicle-treated mice, and in mice treated with RA for 2, 4, and 6 weeks. However, increased staining, in a subepidermal band, was detected in the 8-week RA-treated skin. This region became intensely fluorescent to a depth of 100 mu in the 10-week RA-treated skins. As determined by radioimmunoassay, the content of the AP of type III procollagen increased twofold with 10-week RA treatment. Because the ratio of type I to type III collagens remained constant in treated and untreated skins, it is reasonable to assume that the content of type I collagen increased in proportion to type III collagen in RA-treated skins.

  8. Collagen binding to Staphylococcus aureus

    SciTech Connect

    Holderbaum, D.; Hall, G.S.; Ehrhart, L.A.

    1986-11-01

    Staphylococcus aureus can bind soluble collagen in a specific, saturable manner. We have previously shown that some variability exists in the degree of collagen binding between different strains of heat-killed, formaldehyde-fixed S. aureus which are commercially available as immunologic reagents. The present study demonstrates that live S. aureus of the Cowan 1 strain binds amounts of collagen per organism equivalent to those demonstrated previously in heat-killed, formaldehyde-fixed bacteria but has an affinity over 100 times greater, with Kd values of 9.7 X 10(-11) M and 4.3 X 10(-8) M for live and heat-killed organisms, respectively. Studies were also carried out with S. aureus killed by ionizing radiation, since this method of killing the organism seemed less likely to alter the binding moieties on the surface than did heat killing. Bacteria killed by exposure to gamma radiation bound collagen in a manner essentially indistinguishable from that of live organisms. Binding of collagen to irradiated cells of the Cowan 1 strain was rapid, with equilibrium reached by 30 min at 22 degrees C, and was fully reversible. The binding was not inhibited by fibronectin, fibrinogen, C1q, or immunoglobulin G, suggesting a binding site for collagen distinct from those for these proteins. Collagen binding was virtually eliminated in trypsin-treated organisms, indicating that the binding site has a protein component. Of four strains examined, Cowan 1 and S. aureus ATCC 25923 showed saturable, specific binding, while strains Woods and S4 showed a complete lack of binding. These results suggest that some strains of S. aureus contain high-affinity binding sites for collagen. While the number of binding sites per bacterium varied sixfold in the two collagen-binding strains, the apparent affinity was similar.

  9. ABCB5 identifies immunoregulatory dermal cells

    PubMed Central

    Schatton, Tobias; Yang, Jun; Kleffel, Sonja; Uehara, Mayuko; Barthel, Steven R.; Schlapbach, Christoph; Zhan, Qian; Dudeney, Stephen; Mueller, Hansgeorg; Lee, Nayoung; de Vries, Juliane C.; Meier, Barbara; Vander Beken, Seppe; Kluth, Mark A.; Ganss, Christoph; Sharpe, Arlene H.; Waaga-Gasser, Ana Maria; Sayegh, Mohamed H.; Abdi, Reza; Scharffetter-Kochanek, Karin; Murphy, George F.; Kupper, Thomas S.; Frank, Natasha Y.; Frank, Markus H.

    2015-01-01

    Summary Cell-based strategies represent a new frontier in the treatment of immune-mediated disorders. However, the paucity of markers for isolation of molecularly-defined immunomodulatory cell populations poses a barrier to this field. Here we show that ATP-binding cassette member B5 (ABCB5) identifies dermal immunoregulatory cells (DIRCs) capable of exerting therapeutic immunoregulatory functions through engagement of programmed cell death 1 (PD-1). Purified Abcb5+ DIRCs suppressed T-cell proliferation, evaded immune rejection, homed to recipient immune tissues and induced Tregs in vivo. In fully MHC-mismatched cardiac allotransplantation models, allogeneic DIRCs significantly prolonged allograft survival. Blockade of DIRC-expressed PD-1 reversed the inhibitory effects of DIRCs on T-cell activation, inhibited DIRC-dependent Treg induction, and attenuated DIRC-induced prolongation of cardiac allograft survival, indicating that DIRC immunoregulatory function is mediated, at least in part, through PD-1. Our results identify ABCB5+ DIRCs as a distinct immunoregulatory cell population and suggest promising roles of this expandable cell subset in cellular immunotherapy. PMID:26321644

  10. Vesicular carriers for dermal drug delivery.

    PubMed

    Sinico, Chiara; Fadda, Anna Maria

    2009-08-01

    The skin can offer several advantages as a route of drug administration although its barrier nature makes it difficult for most drugs to penetrate into and permeate through it. During the past decades there has been a lot of interest in lipid vesicles as a tool to improve drug topical delivery. Vesicular systems such as liposomes, niosomes, ethosomes and elastic, deformable vesicles provide an alternative for improved skin drug delivery. The function of vesicles as topical delivery systems is controversial with variable effects being reported in relation to the type of vesicles and their composition. In fact, vesicles can act as drug carriers controlling active release; they can provide a localized depot in the skin for dermally active compounds and enhance transdermal drug delivery. A wide variety of lipids and surfactants can be used to prepare vesicles, which are commonly composed of phospholipids (liposomes) or non-ionic surfactants (niosomes). Vesicle composition and preparation method influence their physicochemical properties (size, charge, lamellarity, thermodynamic state, deformability) and therefore their efficacy as drug delivery systems. A review of vesicle value in localizing drugs within the skin at the site of action will be provided with emphasis on their potential mechanism of action.

  11. Human dermal fibroblasts in psychiatry research.

    PubMed

    Kálmán, S; Garbett, K A; Janka, Z; Mirnics, K

    2016-04-21

    In order to decipher the disease etiology, progression and treatment of multifactorial human brain diseases we utilize a host of different experimental models. Recently, patient-derived human dermal fibroblast (HDF) cultures have re-emerged as promising in vitro functional system for examining various cellular, molecular, metabolic and (patho)physiological states and traits of psychiatric disorders. HDF studies serve as a powerful complement to postmortem and animal studies, and often appear to be informative about the altered homeostasis in neural tissue. Studies of HDFs from patients with schizophrenia (SZ), depression, bipolar disorder (BD), autism, attention deficit and hyperactivity disorder and other psychiatric disorders have significantly advanced our understanding of these devastating diseases. These reports unequivocally prove that signal transduction, redox homeostasis, circadian rhythms and gene*environment (G*E) interactions are all amenable for assessment by the HDF model. Furthermore, the reported findings suggest that this underutilized patient biomaterial, combined with modern molecular biology techniques, may have both diagnostic and prognostic value, including prediction of response to therapeutic agents.

  12. Dermal absorption of inorganic germanium in rats.

    PubMed

    Yokoi, Katsuhiko; Kawaai, Takae; Konomi, Aki; Uchida, Yuka

    2008-11-01

    So-called germanium 'health' products including dietary supplements, cosmetics, accessories, and warm bath service containing germanium compounds and metalloid are popular in Japan. Subchronic and chronic oral exposure of germanium dioxide (GeO(2)), popular chemical form of inorganic germanium causes severe germanium toxicosis including death and kidney dysfunction in humans and experimental animals. Intestinal absorption of neutralized GeO(2) or germanate is almost complete in humans and animals. However, it is not known whether germanium is cutaneously absorbed. We tested dermal absorption of neutralized GeO(2) or germanate using male F344/N rats. Three groups of rats were treated with a 3-h topical application of hydrophilic ointment containing graded level of neutralized GeO(2) (pH 7.4): 0, 0.21 and 0.42 mg GeO(2)/g. Germanium concentration in blood and tissues sampled from rats after topical application of inorganic germanium was measured by inductively coupled plasma-mass spectrometry. Animals topically applied 0.42 mg GeO(2)/g ointment had significantly higher germanium concentrations in plasma, liver, and kidney than those of rats that received no topical germanium. The results indicate that skin is permeable to inorganic germanium ion or germanate and recurrent exposure of germanium compounds may pose a potential health hazard.

  13. Emotional intelligence and electro-dermal activity.

    PubMed

    Zysberg, Leehu

    2012-09-01

    Emotional intelligence (EI) is a promising concept in our understanding of emotional regulation, related behaviors and pathologies. However, research linking EI to underlying physiological and biological structure and responses is meager. This study explored potential associations of EI with electro-dermal activity (EDA) responses to emotionally arousing visual stimuli. It was hypothesized that higher levels of EI will associate with more efficient emotional regulation as reflected by EDA. Eighty-four healthy participants were exposed to stimuli consisting of a series of 12 images designed to evoke positive or negative emotional responses, presented in a counterbalanced order. A self-report questionnaire and a computer based test of EI were administered along with a demographic questionnaire. EDA measures were taken during the exposure to the above stimuli using BIOPACK MP150. EI test scores (Beta = .35, .32; p < .001) and age (Beta = -.24, -.31; p < .03) associated with EDA delta (stimulus response-baseline) scores, while the self-report measure of EI and other demographics (e.g., gender. ethnicity) did not show any associations with the outcome measures. The results support the relevance of the concept to our understanding of emotional responses and regulation. The findings are briefly discussed within the context of underlying mechanisms of EI as well as measure validity and relevance.

  14. Acellular dermal graft reinforcement at the hiatus.

    PubMed

    Freedman, Bruce

    2012-11-01

    The ideal technique to repair large hiatal and diaphragmatic defects remains controversial. Due to high recurrence rates with primary repair alone, attempts at crural reinforcement with various products has been investigated. Initial evaluation of synthetic mesh at the hiatus in retrospective studies led to the conclusion that there were too many serious complications with these products. The next step was to see how biologic grafts fared in this location. Beginning with porcine intestine submucosa in a laminated array and progressing through human and porcine acellular dermal matrices, multiple, retrospective studies looked at the efficacy and safety of these products. Unfortunately, most of these studies evaluated a small sample size with a relatively short follow-up period. The one study followed out to 5 years failed to show any benefit using the biologic (porcine intestinal submucosa) compared with the primary repair alone. Additional, prospective, randomized studies with ample numbers carried out for years will be necessary to see which biologic graft is not only safe but also successful in preventing recurrent herniations.

  15. Electrostatic effects in collagen fibrillization

    NASA Astrophysics Data System (ADS)

    Morozova, Svetlana; Muthukumar, Murugappan

    2014-03-01

    Using light scattering and AFM techniques, we have measured the kinetics of fibrillization of collagen (pertinent to the vitreous of human eye) as a function of pH and ionic strength. At higher and lower pH, collagen triple-peptides remain stable in solution without fibrillization. At neutral pH, the fibrillization occurs and its growth kinetics is slowed upon either an increase in ionic strength or a decrease in temperature. We present a model, based on polymer crystallization theory, to describe the observed electrostatic nature of collagen assembly.

  16. Synthesis of highly interconnected 3D scaffold from Arothron stellatus skin collagen for tissue engineering application.

    PubMed

    Ramanathan, Giriprasath; Singaravelu, Sivakumar; Raja, M D; Sivagnanam, Uma Tiruchirapalli

    2015-11-01

    The substrate which is avidly used for tissue engineering applications should have good mechanical and biocompatible properties, and all these parameters are often considered as essential for dermal reformation. Highly interconnected three dimensional (3D) wound dressing material with enhanced structural integrity was synthesized from Arothron stellatus fish skin (AsFS) collagen for tissue engineering applications. The synthesized 3D collagen sponge (COL-SPG) was further characterized by different physicochemical methods. The scanning electron microscopy analysis of the material demonstrated that well interconnected pores with homogeneous microstructure on the surface aids higher swelling index and that the material also possessed good mechanical properties with a Young's modulus of 0.89±0.2 MPa. Biocompatibility of the 3D COL-SPG showed 92% growth for both NIH 3T3 fibroblasts and keratinocytes. Overall, the study revealed that synthesized 3D COL-SPG from fish skin will act as a promising wound dressing in skin tissue engineering.

  17. Autoantibodies to Multiple Epitopes on the Non-Collagenous-1 Domain of Type VII Collagen Induce Blisters.

    PubMed

    Vorobyev, Artem; Ujiie, Hideyuki; Recke, Andreas; Buijsrogge, Jacqueline J A; Jonkman, Marcel F; Pas, Hendri H; Iwata, Hiroaki; Hashimoto, Takashi; Kim, Soo-Chan; Hoon Kim, Jong; Groves, Richard; Samavedam, Unni; Gupta, Yask; Schmidt, Enno; Zillikens, Detlef; Shimizu, Hiroshi; Ludwig, Ralf J

    2015-06-01

    Epidermolysis bullosa acquisita (EBA) is an autoimmune blistering disease of the skin and mucous membranes, characterized by autoantibodies against type VII collagen (COL7), a major component of anchoring fibrils. Different clinical EBA phenotypes are described, including mechanobullous and inflammatory variants. Most EBA patients' sera react with epitopes located within the non-collagenous 1 (NC1) domain of human COL7. However, it has remained unclear whether antibody binding to these different epitopes is pathogenically relevant. To address this issue, we generated recombinant proteins covering the entire NC1 domain. IgG reactivity with these proteins was analyzed in sera of 69 EBA patients. Most recognized clusters of epitopes throughout the NC1 domain. No correlation was detected between antibody specificity and clinical phenotype. To study the pathogenicity of antibodies specific to different NC1 subdomains, rabbit antibodies were generated. All these antibodies caused dermal-epidermal separation ex vivo. Antibodies against two of these subdomains were injected into mice carrying null mutations of mouse COL7 and the human COL7 transgene and induced subepidermal blisters. We here document that autoantibodies to COL7, independent of the targeted epitopes, induce blisters both ex vivo and in vivo. In addition, using COL7-humanized mice, we provide in vivo evidence of pathogenicity of autoantibodies binding to human COL7.

  18. Optimally oriented grooves on dental implants improve bone quality around implants under repetitive mechanical loading.

    PubMed

    Kuroshima, Shinichiro; Nakano, Takayoshi; Ishimoto, Takuya; Sasaki, Muneteru; Inoue, Maaya; Yasutake, Munenori; Sawase, Takashi

    2017-01-15

    The aim was to investigate the effect of groove designs on bone quality under controlled-repetitive load conditions for optimizing dental implant design. Anodized Ti-6Al-4V alloy implants with -60° and +60° grooves around the neck were placed in the proximal tibial metaphysis of rabbits. The application of a repetitive mechanical load was initiated via the implants (50N, 3Hz, 1800 cycles, 2days/week) at 12weeks after surgery for 8weeks. Bone quality, defined as osteocyte density and degree of biological apatite (BAp) c-axis/collagen fibers, was then evaluated. Groove designs did not affect bone quality without mechanical loading; however, repetitive mechanical loading significantly increased bone-to-implant contact, bone mass, and bone mineral density (BMD). In +60° grooves, the BAp c-axis/collagen fibers preferentially aligned along the groove direction with mechanical loading. Moreover, osteocyte density was significantly higher both inside and in the adjacent region of the +60° grooves, but not -60° grooves. These results suggest that the +60° grooves successfully transmitted the load to the bone tissues surrounding implants through the grooves. An optimally oriented groove structure on the implant surface was shown to be a promising way for achieving bone tissue with appropriate bone quality. This is the first report to propose the optimal design of grooves on the necks of dental implants for improving bone quality parameters as well as BMD. The findings suggest that not only BMD, but also bone quality, could be a useful clinical parameter in implant dentistry.

  19. Implantable electrode for recording nerve signals in awake animals

    NASA Technical Reports Server (NTRS)

    Ninomiya, I.; Yonezawa, Y.; Wilson, M. F.

    1976-01-01

    An implantable electrode assembly consisting of collagen and metallic electrodes was constructed to measure simultaneously neural signals from the intact nerve and bioelectrical noises in awake animals. Mechanical artifacts, due to bodily movement, were negligibly small. The impedance of the collagen electrodes, measured in awake cats 6-7 days after implantation surgery, ranged from 39.8-11.5 k ohms at a frequency range of 20-5 kHz. Aortic nerve activity and renal nerve activity, measured in awake conditions using the collagen electrode, showed grouped activity synchronous with the cardiac cycle. Results indicate that most of the renal nerve activity was from postganglionic sympathetic fibers and was inhibited by the baroceptor reflex in the same cardiac cycle.

  20. Collagen XVII and BPAG1 Expression in the Retina: Evidence for an Anchoring Complex in the Central Nervous System

    PubMed Central

    Claudepierre, Thomas; Manglapus, Mary K.; Marengi, Nathan; Radner, Stephanie; Champliaud, Marie-France; Tasanen, Kaisa; Bruckner-Tuderman, Leena; Hunter, Dale D.; Brunken, William J.

    2010-01-01

    The ectoderm gives rise not only to the skin but also to the entire CNS. This common embryonic lineage suggests that some molecular isoforms might serve analogous functions in both tissues. Indeed, not only are laminins important components of dermal adhesion mechanisms, but they also regulate some aspects of synaptic development in both the CNS and the PNS. In the skin, laminins are part of a hemidesmosome complex essential for basal keratinocyte adhesion that includes collagen XVII (BP180) and BPAG1 (dystonin/BP230). Here, we show that CNS neurons also express collagen XVII and BPAG1 and that these molecules are expressed in the adult and developing retina. In the retina, isoforms of collagen XVII and BPAG1 are colocalized with laminins at photoreceptor synapses and around photoreceptor outer segments; both molecules are expressed by rods, whereas cones express collagen XVII but not BPAG1. Moreover, biochemical data demonstrate that collagen XVII complexes with retinal laminins. We propose that collagen XVII and BPAG1 isoforms may help to anchor elements of the rod photoreceptor cytomatrix to the extracellular matrix. PMID:15880472

  1. Asphalt fume dermal carcinogenicity potential: I. dermal carcinogenicity evaluation of asphalt (bitumen) fume condensates.

    PubMed

    Clark, Charles R; Burnett, Donald M; Parker, Craig M; Arp, Earl W; Swanson, Mark S; Minsavage, Gary D; Kriech, Anthony J; Osborn, Linda V; Freeman, James J; Barter, Robert A; Newton, Paul E; Beazley, Shelley L; Stewart, Christopher W

    2011-10-01

    Asphalt (bitumen) fume condensates collected from the headspace above paving and Type III built up roofing asphalt (BURA) tanks were evaluated in two-year dermal carcinogenicity assays in male C3H/HeNCrl mice. A third sample was generated from the BURA using a NIOSH laboratory generation method. Similar to earlier NIOSH studies, the BURA fume condensates were applied dermally in mineral oil twice per week; the paving sample was applied 7 days/week for a total weekly dose of 50 mg/wk in both studies. A single benign papilloma was observed in a group of 80 mice exposed to paving fume condensate at the end of the two-year study and only mild skin irritation was observed. The lab generated BURA fume condensate resulted in statistically significant (P<0.0001) increases in squamous cell carcinomas (35 animals or 55% of animals at risk). The field-matched BURA condensate showed a weaker but significant (P=0.0063) increase (8 carcinomas or 13% of animals) and a longer average latency (90 weeks vs. 76 for the lab fume). Significant irritation was observed in both BURA condensates. It is concluded that the paving fume condensate was not carcinogenic under the test conditions and that the field-matched BURA fume condensate produced a weak tumor response compared to the lab generated sample.

  2. Structural variations in anchoring fibrils in dystrophic epidermolysis bullosa: correlation with type VII collagen expression.

    PubMed

    McGrath, J A; Ishida-Yamamoto, A; O'Grady, A; Leigh, I M; Eady, R A

    1993-04-01

    Dystrophic epidermolysis bullosa is characterized by various abnormalities of anchoring fibrils, which are mainly composed of type VII collagen, at the dermal-epidermal junction. To define these changes more clearly, we examined skin samples from 22 patients with different forms of dystrophic epidermolysis bullosa by pre-embedding immunoelectron microscopy using an antibody (LH 7:2) that binds to the NC-1 globular domain of type VII collagen, followed by 1 nm colloidal gold-labeled secondary antibodies and subsequent silver enhancement. In dominant dystrophic epidermolysis bullosa cases, there was only a slight but variable reduction in the immunolabeling density on anchoring fibrils and on the lamina densa, in parts similar to normal human skin. In localized recessive dystrophic epidermolysis bullosa skin, some fibrillar structures just below the lamina densa (and particularly subjacent to hemidesmosomes) had specific antibody labeling despite their lack of resemblance to definitive anchoring fibrils. Immunolabeling with LH 7:2 was also seen within basal keratinocyte endoplasmic reticulum and cytoplasmic vesicles in some dystrophic epidermolysis bullosa patients, usually with milder phenotypic features. Even in the most severe cases of generalized recessive dystrophic epidermolysis bullosa, occasional immunolabeling was found within the lamina densa and on scanty thin filamentous structures at sub-lamina densa sites usually occupied by anchoring fibrils. This study suggests that dystrophic epidermolysis bullosa patients express some type VII collagen NC-1 domain epitopes that may be variably reduced at the dermal-epidermal junction or retained within basal keratinocytes. The clinical heterogeneity in dystrophic epidermolysis bullosa is mirrored by a range of immunoelectron microscopy findings, indicating variability in completeness of anchoring fibril formation and a possible spectrum of underlying type VII collagen structural protein abnormalities.

  3. Royal Jelly Increases Collagen Production in Rat Skin After Ovariectomy

    PubMed Central

    Park, Hye Min; Cho, Min Hyoung; Cho, Yunhi

    2012-01-01

    Abstract Royal jelly (RJ) is a honeybee product that contains proteins, carbohydrates, fats, free amino acids, vitamins, and minerals. RJ has been reported to have antitumor, antibacterial, and wound-healing activities. We previously reported that RJ enhanced the migration of human dermal fibroblasts and altered the levels of cholesterol and sphinganine in an in vitro wound-healing model in addition to regulating skin photoaging following exposure to ultraviolet-B radiation. We established an animal model of skin aging in the context of estrogen deficiency and assessed the antiaging effects of RJ on skin. To establish an in vivo model of skin aging, bilateral ovariectomies were performed in 12-week-old virgin female Sprague-Dawley rats. Induction of osteoporosis was confirmed through two-dimensional images of the trabecular bone in the left femoral necks using microcomputed tomography. The protective effects of RJ ovariectomy-induced skin aging were examined by determining the protein expression of type I procollagen and matrix metalloproteinase (MMP)-1. The collagen content and epidermal thickness of skin tissue were measured by staining techniques. There was a significant difference in weight between sham-operated and ovariectomized groups. Food efficiency ratio did not differ significantly among the groups. The level of procollagen type I protein was increased in the dorsal skin of ovariectomized rats fed with a dietary supplement containing 1% RJ extract, but the level of MMP-1 was not altered. In particular, the amount of collagen recovered was close to the normal level. RJ may protect against skin aging by enhancing collagen production in rats with ovariectomy-induced estrogen deficiency. PMID:22468645

  4. Methamphetamine residue dermal transfer efficiencies from household surfaces.

    PubMed

    Van Dyke, Mike; Martyny, John W; Serrano, Kate A

    2014-01-01

    Methamphetamine contamination from illegal production operations poses a potential health concern for emergency responders, child protective services, law enforcement, and children living in contaminated structures. The objective of this study was to evaluate dermal transfer efficiencies of methamphetamine from contaminated household surfaces. These transfer efficiencies are lacking for methamphetamine, and would be beneficial for use in exposure models. Surfaces were contaminated using a simulated smoking method in a stainless steel chamber. Household surfaces were carpet, painted drywall, and linoleum. Dermal transfer efficiencies were obtained using cotton gloves for two hand conditions, dry or saliva moistened (wet). In addition, three contact scenarios were evaluated for both hand conditions: one, two, or three contacts with contaminated surfaces. Dermal transfer efficiencies were calculated for both hand conditions and used as inputs in a Stochastic Human Exposure and Dose Simulation model (SHEDS-Multimedia, Office of Research and Development, United States Environmental Protection Agency, Research Triangle Park, N.C.). Results of this study showed that average dermal transfer efficiencies of methamphetamine ranged from 11% for dry hands to 26% for wet hands. There was a significantly higher wet transfer as compared to dry transfer for all surfaces. For wet hands, dermal transfer depended on surface type with higher transfer from carpet and linoleum as compared to drywall. Based on our estimates of dermal transfer efficiency, a surface contamination clearance level of 1.5 μg/100 cm(2) may not ensure absorbed doses remain below the level associated with adverse health effects in all cases. Additional dermal transfer studies should be performed using skin surrogates that may better predict actual skin transfer.

  5. Clinical uses of collagen shields.

    PubMed

    Poland, D E; Kaufman, H E

    1988-09-01

    Collagen shields immersed in tobramycin solution for one minute were applied to one eye each of 60 patients who had had cataract extraction, penetrating keratoplasty, or epikeratophakia or who had nonsurgical epithelial healing problems. The shields were well tolerated; one patient had the shield removed and one patient lost the shield in the early postoperative period. The surgical patients showed more rapid healing of epithelial defects after surgery with the use of the collagen shield. Patients with acute nonsurgical epithelial problems, such as contact lens abrasions and recurrent erosion, responded to the use of the collagen shield with improved healing. Patients with chronic epithelial defects responded poorly, presumably because underlying abnormalities in Bowman's layer prevented epithelial growth in the area of the defect. No infections were noted in any of the patients. The collagen shields appear to promote enhanced healing in patients with postsurgical and acute epithelial defects and to provide adequate antibiotic prophylaxis against infection in these vulnerable eyes.

  6. Endothelial Cell Growth and Differentiation on Collagen-Immobilized Polycaprolactone Nanowire Surfaces.

    PubMed

    Leszczak, Victoria; Baskett, Dominique A; Popat, Ketul C

    2015-06-01

    The success of cardiovascular implants is associated with the development of an endothelium on material surface, critical to the prevention of intimal hyperplasia, calcification and thrombosis. A thorough understanding of the interaction between vascular endothelial cells and the biomaterial involved is essential in order to have a successful application which promotes healing and regeneration through integration with native tissue. In this study, we have developed collagen immobilized nanostructured surfaces with controlled arrays of high aspect ratio nanowires for the growth and maintenance of human microvascular endothelial cells (HMVECs). The nanowire surfaces were fabricated from polycaprolactone using a novel nanotemplating technique, and were immobilized with collagen utilizing an aminolysis method. The collagen immobilized nanowire surfaces were characterized using contact angle measurements, scanning electron microscopy and X-ray photoelectron spectroscopy. Human microvascular endothelial cells were used to evaluate the efficacy of the collagen immobilized nanowire surfaces to promote cell adhesion, proliferation, viability and differentiation. The results presented here indicate significantly higher cellular adhesion, proliferation and viability on nanowire and collagen immobilized surfaces as compared to the control surface. Further, HMVECs have a more elongated body and low shape factor on nanostructured surfaces. The differentiation potential of collagen immobilized nanowire surfaces was also evaluated by immunostaining and western blotting for key endothelial cell markers that are expressed when human microvascular endothelial cells are differentiated. Results indicate that expression of VE-cadherin is increased on collagen immobilized surfaces while the expression of von Willebrand factor is statistically similar on all surfaces.

  7. A biomaterial composed of collagen and solubilized elastin enhances angiogenesis and elastic fiber formation without calcification.

    PubMed

    Daamen, Willeke F; Nillesen, Suzan T M; Wismans, Ronnie G; Reinhardt, Dieter P; Hafmans, Theo; Veerkamp, Jacques H; van Kuppevelt, Toin H

    2008-03-01

    Elastin is the prime protein in elastic tissues that contributes to elasticity of, for example, lung, aorta, and skin. Upon injury, elastic fibers are not readily replaced, which hampers tissue regeneration. Incorporation of solubilized elastin (hydrolyzed insoluble elastin fibers or elastin peptides) in biomaterials may improve regeneration, because solubilized elastin is able to promote proliferation as well as elastin synthesis. Porous biomaterials composed of highly purified collagen without and without elastin fibers or solubilized elastin were prepared by freezing and lyophilization. Solubilized elastin formed spherical structures that were incorporated in the collagenous part of the scaffolds and that persisted after chemical crosslinking of the scaffolds. Crosslinked scaffolds were subcutaneously implanted in young Sprague Dawley rats. Collagen-solubilized elastin and collagen scaffolds showed no calcification in this sensitive calcification model, in contrast to scaffolds containing elastin fibers. Collagen-solubilized elastin scaffolds also induced angiogenesis, as revealed by type IV collagen staining, and promoted elastic fiber synthesis, as shown with antibodies against rat elastin and fibrillin-1. It is concluded that scaffolds produced from collagen and solubilized elastin present a non-calcifying biomaterial with a capacity for soft-tissue regeneration, especially in relation to elastic fiber synthesis.

  8. Fibrils of different collagen types containing immobilised proteoglycans (PGs) as coatings: characterisation and influence on osteoblast behaviour.

    PubMed

    Douglas, T; Hempel, U; Mietrach, C; Heinemann, S; Scharnweber, D; Worch, H

    2007-11-01

    Collagen, the main organic component of bone, is used as a coating on titanium implants and as a scaffold material in bone tissue engineering. Surface modifications of titanium which promote osteoblast adhesion, proliferation and synthesis of collagen by osteoblasts are desirable. One biomimetic approach is the coating of titanium with collagen in fibrillar form. Other organic components of bone may be bound to fibrils and exert additional effects. In this study, the collagen types I-III were compared regarding their ability to bind the proteoglycans decorin and biglycan, which are found in bone. More collagen was bound to collagen II fibrils than to those of types I and III. Therefore, titanium surfaces were coated with fibrils of collagen type II containing biglycan or decorin or neither to investigate the effect of the proteoglycans on human primary osteoblast behaviour. In addition, the growth factor TGF-beta1 was adsorbed onto surfaces coated with fibrils of collagen type II containing biglycan or decorin or neither to investigate the influence of decorin and biglycan on the effect of TGF-beta1 on osteoblasts. Fibril-bound biglycan and decorin influence primary osteoblast behaviour by themselves. The presence of substrate-bound biglycan or decorin influences the effect of TGF-beta1. These results may be important when designing collagen-based coatings or scaffolds for tissue engineering, including those loaded with growth factors.

  9. Short Implants: New Horizon in Implant Dentistry.

    PubMed

    Jain, Neha; Gulati, Manisha; Garg, Meenu; Pathak, Chetan

    2016-09-01

    The choice of implant length is an essential factor in deciding the survival rates of these implants and the overall success of the prosthesis. Placing an implant in the posterior part of the maxilla and mandible has always been very critical due to poor bone quality and quantity. Long implants can be placed in association with complex surgical procedures such as sinus lift and bone augmentation. These techniques are associated with higher cost, increased treatment time and greater morbidity. Hence, there is need for a less invasive treatment option in areas of poor bone quantity and quality. Data related to survival rates of short implants, their design and prosthetic considerations has been compiled and structured in this manuscript with emphasis on the indications, advantages of short implants and critical biomechanical factors to be taken into consideration when choosing to place them. Studies have shown that comparable success rates can be achieved with short implants as those with long implants by decreasing the lateral forces to the prosthesis, eliminating cantilevers, increasing implant surface area and improving implant to abutment connection. Short implants can be considered as an effective treatment alternative in resorbed ridges. Short implants can be considered as a viable treatment option in atrophic ridge cases in order to avoid complex surgical procedures required to place long implants. With improvement in the implant surface geometry and surface texture, there is an increase in the bone implant contact area which provides a good primary stability during osseo-integration.

  10. Short Implants: New Horizon in Implant Dentistry

    PubMed Central

    Gulati, Manisha; Garg, Meenu; Pathak, Chetan

    2016-01-01

    The choice of implant length is an essential factor in deciding the survival rates of these implants and the overall success of the prosthesis. Placing an implant in the posterior part of the maxilla and mandible has always been very critical due to poor bone quality and quantity. Long implants can be placed in association with complex surgical procedures such as sinus lift and bone augmentation. These techniques are associated with higher cost, increased treatment time and greater morbidity. Hence, there is need for a less invasive treatment option in areas of poor bone quantity and quality. Data related to survival rates of short implants, their design and prosthetic considerations has been compiled and structured in this manuscript with emphasis on the indications, advantages of short implants and critical biomechanical factors to be taken into consideration when choosing to place them. Studies have shown that comparable success rates can be achieved with short implants as those with long implants by decreasing the lateral forces to the prosthesis, eliminating cantilevers, increasing implant surface area and improving implant to abutment connection. Short implants can be considered as an effective treatment alternative in resorbed ridges. Short implants can be considered as a viable treatment option in atrophic ridge cases in order to avoid complex surgical procedures required to place long implants. With improvement in the implant surface geometry and surface texture, there is an increase in the bone implant contact area which provides a good primary stability during osseo-integration. PMID:27790598

  11. Human collagen produced in plants

    PubMed Central

    Shoseyov, Oded; Posen, Yehudit; Grynspan, Frida

    2014-01-01

    Consequential to its essential role as a mechanical support and affinity regulator in extracellular matrices, collagen constitutes a highly sought after scaffolding material for regeneration and healing applications. However, substantiated concerns have been raised with regard to quality and safety of animal tissue-extracted collagen, particularly in relation to its immunogenicity, risk of disease transmission and overall quality and consistency. In parallel, contamination with undesirable cellular factors can significantly impair its bioactivity, vis-a-vis its impact on cell recruitment, proliferation and differentiation. High-scale production of recombinant human collagen Type I (rhCOL1) in the tobacco plant provides a source of an homogenic, heterotrimeric, thermally stable “virgin” collagen which self assembles to fine homogenous fibrils displaying intact binding sites and has been applied to form numerous functional scaffolds for tissue engineering and regenerative medicine. In addition, rhCOL1 can form liquid crystal structures, yielding a well-organized and mechanically strong membrane, two properties indispensable to extracellular matrix (ECM) mimicry. Overall, the shortcomings of animal- and cadaver-derived collagens arising from their source diversity and recycled nature are fully overcome in the plant setting, constituting a collagen source ideal for tissue engineering and regenerative medicine applications. PMID:23941988

  12. Dermal injection of immunocytes induces psoriasis.

    PubMed

    Wrone-Smith, T; Nickoloff, B J

    1996-10-15

    Establishing direct and causal relationships among the confederacy of activated cell types present in psoriasis has been hampered by lack of an animal model. Within psoriatic plaques there are hyperplastic keratinocytes, infiltrating immunocytes, and activated endothelial cells. The purpose of this study was to determine if psoriasis is primarily a disorder of keratinocytes or the immune system. Using a newly developed experimental system in which full-thickness human skin is orthotopically transferred onto severe combined immunodeficient mice, autologous immunocytes were injected into dermis, and the resultant phenotype characterized by clinical, histologic, and immunophenotypic analyses. Engraftment of samples included both uninvolved/ symptomless (PN) skin removed from patients with psoriasis elsewhere, or from healthy individuals with no skin disease (NN skin). In 10 different experiments involving 6 different psoriasis patients, every PN skin was converted to a full-fledged psoriatic plaque skin by injection of autologous blood-derived immunocytes. In all but one psoriatic patient, the immunocytes required preactivation with IL-2 and superantigens to convert PN skin into psoriatic plaque skin. In every case, resultant plaques were characterized by visible presence of flaking and thickened skin, loss of the granular cell layer, prominent elongation of rete pegs with a dermal angiogenic tissue reaction, and infiltration within the epidermis by T cells. Lesional skin displayed 20 different antigenic determinants of the psoriatic phenotype. None of the four NN skin samples injected with autologous immunocytes converted to psoriatic plaques. We conclude that psoriasis is caused primarily by the ability of pathogenetic blood-derived immunocytes to induce secondary activation and disordered growth of endogenous cutaneous cells including keratinocytes and vascular endothelium.

  13. Dermal injection of immunocytes induces psoriasis.

    PubMed Central

    Wrone-Smith, T; Nickoloff, B J

    1996-01-01

    Establishing direct and causal relationships among the confederacy of activated cell types present in psoriasis has been hampered by lack of an animal model. Within psoriatic plaques there are hyperplastic keratinocytes, infiltrating immunocytes, and activated endothelial cells. The purpose of this study was to determine if psoriasis is primarily a disorder of keratinocytes or the immune system. Using a newly developed experimental system in which full-thickness human skin is orthotopically transferred onto severe combined immunodeficient mice, autologous immunocytes were injected into dermis, and the resultant phenotype characterized by clinical, histologic, and immunophenotypic analyses. Engraftment of samples included both uninvolved/ symptomless (PN) skin removed from patients with psoriasis elsewhere, or from healthy individuals with no skin disease (NN skin). In 10 different experiments involving 6 different psoriasis patients, every PN skin was converted to a full-fledged psoriatic plaque skin by injection of autologous blood-derived immunocytes. In all but one psoriatic patient, the immunocytes required preactivation with IL-2 and superantigens to convert PN skin into psoriatic plaque skin. In every case, resultant plaques were characterized by visible presence of flaking and thickened skin, loss of the granular cell layer, prominent elongation of rete pegs with a dermal angiogenic tissue reaction, and infiltration within the epidermis by T cells. Lesional skin displayed 20 different antigenic determinants of the psoriatic phenotype. None of the four NN skin samples injected with autologous immunocytes converted to psoriatic plaques. We conclude that psoriasis is caused primarily by the ability of pathogenetic blood-derived immunocytes to induce secondary activation and disordered growth of endogenous cutaneous cells including keratinocytes and vascular endothelium. PMID:8878440

  14. Characterization of Ovine Dermal Papilla Cell Aggregation

    PubMed Central

    Sari, Agnes Rosarina Prita; Rufaut, Nicholas Wolfgang; Jones, Leslie Norman; Sinclair, Rodney Daniel

    2016-01-01

    Context: The dermal papilla (DP) is a condensation of mesenchymal cells at the proximal end of the hair follicle, which determines hair shaft size and regulates matrix cell proliferation and differentiation. DP cells have the ability to regenerate new hair follicles. These cells tend to aggregate both in vitro and in vivo. This tendency is associated with the ability of papilla cells to induce hair growth. However, human papilla cells lose their hair-inducing activity in later passage number. Ovine DP cells are different from human DP cells since they do not lose their aggregative behavior or hair-inducing activity in culture. Nonetheless, our understanding of ovine DP cells is still limited. Aim: The aim of this study was to observe the expression of established DP markers in ovine cells and their association with aggregation. Subjects and Methods: Ovine DP cells from three different sheep were compared. Histochemistry, immunoflourescence, and polymerase chain reaction experiments were done to analyze the DP markers. Results: We found that ovine DP aggregates expressed all the 16 markers evaluated, including alkaline phosphatase and versican. Expression of the versican V0 and V3 isoforms, neural cell adhesion molecule, and corin was increased significantly with aggregation, while hey-1 expression was significantly decreased. Conclusions: Overall, the stable expression of numerous markers suggests that aggregating ovine DP cells have a similar phenotype to papillae in vivo. The stability of their molecular phenotype is consistent with their robust aggregative behavior and retained follicle-inducing activity after prolonged culture. Their phenotypic stability in culture contrasts with DP cells from other species, and suggests that a better understanding of ovine DP cells might provide opportunities to improve the hair-inducing activity and therapeutic potential of human cells. PMID:27625564

  15. High-strength mineralized collagen artificial bone

    NASA Astrophysics Data System (ADS)

    Qiu, Zhi-Ye; Tao, Chun-Sheng; Cui, Helen; Wang, Chang-Ming; Cui, Fu-Zhai

    2014-03-01

    Mineralized collagen (MC) is a biomimetic material that mimics natural bone matrix in terms of both chemical composition and microstructure. The biomimetic MC possesses good biocompatibility and osteogenic activity, and is capable of guiding bone regeneration as being used for bone defect repair. However, mechanical strength of existing MC artificial bone is too low to provide effective support at human load-bearing sites, so it can only be used for the repair at non-load-bearing sites, such as bone defect filling, bone graft augmentation, and so on. In the present study, a high strength MC artificial bone material was developed by using collagen as the template for the biomimetic mineralization of the calcium phosphate, and then followed by a cold compression molding process with a certain pressure. The appearance and density of the dense MC were similar to those of natural cortical bone, and the phase composition was in conformity with that of animal's cortical bone demonstrated by XRD. Mechanical properties were tested and results showed that the compressive strength was comparable to human cortical bone, while the compressive modulus was as low as human cancellous bone. Such high strength was able to provide effective mechanical support for bone defect repair at human load-bearing sites, and the low compressive modulus can help avoid stress shielding in the application of bone regeneration. Both in vitro cell experiments and in vivo implantation assay demonstrated good biocompatibility of the material, and in vivo stability evaluation indicated that this high-strength MC artificial bone could provide long-term effective mechanical support at human load-bearing sites.

  16. Toxicity and penetration of TiO2 nanoparticles in hairless mice and porcine skin after subchronic dermal exposure.

    PubMed

    Wu, Jianhong; Liu, Wei; Xue, Chenbing; Zhou, Shunchang; Lan, Fengli; Bi, Lei; Xu, Huibi; Yang, Xiangliang; Zeng, Fan-Dian

    2009-12-01

    The present study investigated the penetration and potential toxicity of titanium dioxide (TiO(2)) nanoparticles following its dermal exposure in vitro and in vivo. In vitro, after exposure to isolated porcine skin for 24h, titanium dioxide nanoparticles of carious sizes cannot penetrate through stratum corneum. Interestingly, when studied in vivo, quite different results were obtained. After topically applied on pig ear for 30 days, TiO(2) nanomaterials (4 nm and 60 nm) can penetrate through horny layer, and be located in deep layer of epidermis. Furthermore, after 60 days dermal exposure in hairless mice, nano-TiO(2) particles can penetrate through the skin, reach different tissues and induce diverse pathological lesions in several major organs. Notably, P25 (21 nm) TiO(2) nanomaterials shows a wider tissue distribution, and can even be found in the brain without inducing any pathological changes. Among all of the organs examined, the skin and liver displayed the most severe pathological changes that correspond to the significant changes in SOD and MDA levels. These results suggest that the pathological lesions are likely to be mediated through the oxidative stress induced by the deposited nanoparticles. Accordingly, the collagen content expressed as HYP content are also significantly reduced in mouse skin samples, indicating that topically applied nano-TiO(2) in skin for a prolonged time can induce skin aging. Altogether, the present study indicates that nanosize TiO(2) may pose a health risk to human after dermal exposure over a relative long time period.

  17. Contraction-induced Mmp13 and -14 expression by goat articular chondrocytes in collagen type I but not type II gels.

    PubMed

    Berendsen, Agnes D; Vonk, Lucienne A; Zandieh-Doulabi, Behrouz; Everts, Vincent; Bank, Ruud A

    2012-10-01

    Collagen gels are promising scaffolds to prepare an implant for cartilage repair but several parameters, such as collagen concentration and composition as well as cell density, should be carefully considered, as they are reported to affect phenotypic aspects of chondrocytes. In this study we investigated whether the presence of collagen type I or II in gel lattices affects matrix contraction and relative gene expression levels of matrix proteins, MMPs and the subsequent degradation of collagen by goat articular chondrocytes. Only floating collagen I gels, and not those attached or composed of type II collagen, contracted during a culture period of 12 days. This coincided with an upregulation of both Mmp13 and -14 gene expression, whereas Mmp1 expression was not affected. The release of hydroxyproline in the culture medium, indicating matrix degradation, was increased five-fold in contracted collagen I gels compared to collagen II gels without contraction. Furthermore, blocking contraction of collagen I gels by cytochalasin B inhibited Mmp13 and -14 expression and the release of hydroxyproline. The expression of cartilage-specific ECM genes was decreased in contracted collagen I gels, with increased numbers of cells with an elongated morphology, suggesting that matrix contraction induces dedifferentiation of chondrocytes into fibroblast-like cells. We conclude that the collagen composition of the gels affects matrix contraction by articular chondrocytes and that matrix contraction induces an increased Mmp13 and -14 expression as well as matrix degradation.

  18. Collagen-chitosan scaffold modified with Au and Ag nanoparticles: Synthesis and structure

    NASA Astrophysics Data System (ADS)

    Rubina, M. S.; Kamitov, E. E.; Zubavichus, Ya. V.; Peters, G. S.; Naumkin, A. V.; Suzer, S.; Vasil'kov, A. Yu.

    2016-03-01

    Nowadays, the dermal biomimetic scaffolds are widely used in regenerative medicine. Collagen-chitosan scaffold one of these materials possesses antibacterial activity, good compatibility with living tissues and has been already used as a wound-healing material. In this article, collagen-chitosan scaffolds modified with Ag and Au nanoparticles have been synthesized using novel method - the metal-vapor synthesis. The nanocomposite materials are characterized by XPS, TEM, SEM and synchrotron radiation-based X-ray techniques. According to XRD data, the mean size of the nanoparticles (NPs) is 10.5 nm and 20.2 nm in Au-Collagen-Chitosan (Au-CollCh) and Ag-Collagen-Chitosan (Ag-CollCh) scaffolds, respectively in fair agreement with the TEM data. SAXS analysis of the composites reveals an asymmetric size distribution peaked at 10 nm for Au-CollCh and 25 nm for Ag-CollCh indicative of particle's aggregation. According to SEM data, the metal-carrying scaffolds have layered structure and the nanoparticles are rather uniformly distributed on the surface material. XPS data indicate that the metallic nanoparticles are in their unoxidized/neutral states and dominantly stabilized within the chitosan-rich domains.

  19. Preparation and characterization of collagen from soft-shelled turtle (Pelodiscus sinensis) skin for biomaterial applications.

    PubMed

    Nagai, Nobuhiro; Kobayashi, Hatsumi; Katayama, Shizuka; Munekata, Masanobu

    2009-01-01

    Collagen was isolated from the skin of soft-shelled turtle (Pelodiscus sinensis) by acid solubilization with pepsin. The yield of soft-shelled turtle collagen (STC) was 12.1% on a dry weight basis. The electrophoresis assay showed that STC consisted of a alpha(1)alpha(2) heterodimer similar to porcine collagen (PC). Amino-acid composition analysis showed that the hydroxyproline content of STC was 7.8%, which was lower than that of PC (9.5%). The denaturation temperature of STC was 36 degrees C from optical rotation analysis. An accelerated fibrillogenesis of STC was observed in phosphate-buffered saline at 25 degrees C. The resulting STC fibrillar gel had microfibrillar network with fibril diameter of ca. 124 nm, as revealed by observation with scanning electron microscopy. The compressive moduli of the STC gel and the PC gel were 3.2 +/- 0.8 kPa and 3.6 +/- 0.3 kPa, respectively. The potential of the STC gel for biomaterial applications was investigated by in vitro cell culture. Human dermal fibroblasts were three-dimensionally cultured in the STC gel and their growth was evaluated by DNA content measurement. Steady growth was observed in the STC gel for a 6-day culture period, although the growth rate was slower than in the PC gel. In conclusion, STC could be used as a novel collagen source for biomaterial applications.

  20. Safety and efficacy of composite collagen-silver nanoparticle hydrogels as tissue engineering scaffolds

    NASA Astrophysics Data System (ADS)

    Alarcon, Emilio I.; Udekwu, Klas I.; Noel, Christopher W.; Gagnon, Luke B.-P.; Taylor, Patrick K.; Vulesevic, Branka; Simpson, Madeline J.; Gkotzis, Spyridon; Islam, M. Mirazul; Lee, Chyan-Jang; Richter-Dahlfors, Agneta; Mah, Thien-Fah; Suuronen, Erik J.; Scaiano, Juan C.; Griffith, May

    2015-11-01

    The increasing number of multidrug resistant bacteria has revitalized interest in seeking alternative sources for controlling bacterial infection. Silver nanoparticles (AgNPs), are amongst the most promising candidates due to their wide microbial spectrum of action. In this work, we report on the safety and efficacy of the incorporation of collagen coated AgNPs into collagen hydrogels for tissue engineering. The resulting hybrid materials at [AgNPs] < 0.4 μM retained the mechanical properties and biocompatibility for primary human skin fibroblasts and keratinocytes of collagen hydrogels; they also displayed remarkable anti-infective properties against S. aureus, S. epidermidis, E. coli and P. aeruginosa at considerably lower concentrations than silver nitrate. Further, subcutaneous implants of materials containing 0.2 μM AgNPs in mice showed a reduction in the levels of IL-6 and other inflammation markers (CCL24, sTNFR-2, and TIMP1). Finally, an analysis of silver contents in implanted mice showed that silver accumulation primarily occurred within the tissue surrounding the implant.The increasing number of multidrug resistant bacteria has revitalized interest in seeking alternative sources for controlling bacterial infection. Silver nanoparticles (AgNPs), are amongst the most promising candidates due to their wide microbial spectrum of action. In this work, we report on the safety and efficacy of the incorporation of collagen coated AgNPs into collagen hydrogels for tissue engineering. The resulting hybrid materials at [AgNPs] < 0.4 μM retained the mechanical properties and biocompatibility for primary human skin fibroblasts and keratinocytes of collagen hydrogels; they also displayed remarkable anti-infective properties against S. aureus, S. epidermidis, E. coli and P. aeruginosa at considerably lower concentrations than silver nitrate. Further, subcutaneous implants of materials containing 0.2 μM AgNPs in mice showed a reduction in the levels of IL-6 and

  1. Mesenchymal stem cell-coated sutures enhance collagen depositions in sutured tissues.

    PubMed

    Casado, Javier G; Blazquez, Rebeca; Jorge, Inmaculada; Alvarez, Veronica; Gomez-Mauricio, Guadalupe; Ortega-Muñoz, Mariano; Vazquez, Jesus; Sanchez-Margallo, Francisco M

    2014-01-01

    Sutures are commonly used for surgical procedures and new sutures are being developed to improve wound healing. In the past decade, it has been extensively shown that mesenchymal stem cells (MSCs) have a wound healing potential. To benefit the overall wound healing process, we aimed to analyze the usage of pretreated sutures for improving the implantation of MSCs in the tissues. Our results firstly showed that suture pretreatments with gelatin, poly-L-lysine, and NaOH improved the adhesive strength of MSCs to sutures. These cells remained surrounding the sutured tissue and no significant phenotypic changes were found in those cells cultured onto pretreated sutures. In vivo experiments showed that the implantation of MSCs by suturing increases the collagen content in the sutured tissue. Moreover, proteomics analysis of secreted proteins showed that collagen alpha-1(I) chain was the most abundant collagen found. To our knowledge, this is the first report that aimed to improve the implantation of MSCs in tissue by suture pretreatments. Moreover, in vivo experiments suggest that MSC-coated sutures may enhance wound healing and tissue remodeling through the release of different collagen types being applicable for those patients that tend to have difficulty healing.

  2. Induction of predominant tenogenic phenotype in human dermal fibroblasts via synergistic effect of TGF-β and elongated cell shape.

    PubMed

    Wang, Wenbo; Li, Jie; Wang, Keyun; Zhang, Zhiyong; Zhang, Wenjie; Zhou, Guangdong; Cao, Yilin; Ye, Mingliang; Zou, Hanfa; Liu, Wei

    2016-03-01

    Micropattern topography is widely investigated for its role in mediating stem cell differentiation, but remains unexplored for phenotype switch between mature cell types. This study investigated the potential of inducing tenogenic phenotype in human dermal fibroblasts (hDFs) by artificial elongation of cultured cells. Our results showed that a parallel microgrooved topography could convert spread hDFs into an elongated shape and induce a predominant tenogenic phenotype as the expression of biomarkers was significantly enhanced, such as scleraxis, tenomodulin, collagens I, III, VI, and decorin. It also enhanced the expression of transforming growth factor (TGF)-β1, but not α-smooth muscle actin. Elongated hDFs failed to induce other phenotypes, such as adiopogenic, chondrogenic, neurogenic, and myogenic lineages. By contrast, no tenogenic phenotype could be induced in elongated human chondrocytes, although chondrogenic phenotype was inhibited. Exogenous TGF-β1 could enhance the tenogenic phenotype in elongated hDFs at low dose (2 ng/ml), but promoted myofibroblast transdifferentiation of hDFs at high dose (10 ng/ml), regardless of cell shape. Elongated shape also resulted in decreased RhoA activity and increased Rho-associated protein kinase (ROCK) activity. Antagonizing TGF-β or inhibiting ROCK activity with Y27632 or depolymerizing actin with cytochalasin D could all significantly inhibit tenogenic phenotype induction, particularly in elongated hDFs. In conclusion, elongation of cultured dermal fibroblasts can induce a predominant tenogenic phenotype likely via synergistic effect of TGF-β and cytoskeletal signaling.

  3. Expression of mesenchymal stem cell marker CD90 on dermal sheath cells of the anagen hair follicle in canine species

    PubMed Central

    Mercati, F.; Pascucci, L.; Ceccarelli, P.; Dall’Aglio, C.; Pedini, V.; Gargiulo, A.M.

    2009-01-01

    The dermal sheath (DS) of the hair follicle is comprised by fibroblast-like cells and extends along the follicular epithelium, from the bulb up to the infundibulum. From this structure, cells with stem characteristics were isolated: they have a mesenchymal origin and express CD90 protein, a typical marker of mesenchymal stem cells. It is not yet really clear in which region of hair follicle these cells are located but some experimental evidence suggests that dermal stem cells are localized prevalently in the lower part of the anagen hair follicle. As there are no data available regarding DS stem cells in dog species, we carried out a morphological analysis of the hair follicle DS and performed both an immunohistochemical and an immunocytochemical investigation to identify CD90+ cells. We immunohistochemically evidenced a clear and abundant positivity to CD90 protein in the DS cells located in the lower part of anagen hair follicle. The positive cells showed a typical fibroblast-like morphology. They were flat and elongated and inserted among bundles of collagen fibres.The whole structure formed a close and continuous sleeve around the anagen hair follicle. Our immunocytochemical study allowed us to localize CD90 protein at the cytoplasmic membrane level.

  4. The effect of keratinocytes on the biomechanical characteristics and pore microstructure of tissue engineered skin using deep dermal fibroblasts.

    PubMed

    Varkey, Mathew; Ding, Jie; Tredget, Edward E

    2014-12-01

    Fibrosis affects most organs, it results in replacement of normal parenchymal tissue with collagen-rich extracellular matrix, which compromises tissue architecture and ultimately causes loss of function of the affected organ. Biochemical pathways that contribute to fibrosis have been extensively studied, but the role of biomechanical signaling in fibrosis is not clearly understood. In this study, we assessed the effect keratinocytes have on the biomechanical characteristics and pore microstructure of tissue engineered skin made with superficial or deep dermal fibroblasts in order to determine any biomaterial-mediated anti-fibrotic influences on tissue engineered skin. Tissue engineered skin with deep dermal fibroblasts and keratinocytes were found to be less stiff and contracted and had reduced number of myofibroblasts and lower expression of matrix crosslinking factors compared to matrices with deep fibroblasts alone. However, there were no such differences between tissue engineered skin with superficial fibroblasts and keratinocytes and matrices with superficial fibroblasts alone. Also, tissue engineered skin with deep fibroblasts and keratinocytes had smaller pores compared to those with superficial fibroblasts and keratinocytes; pore size of tissue engineered skin with deep fibroblasts and keratinocytes were not different from those matrices with deep fibroblasts alone. A better understanding of biomechanical characteristics and pore microstructure of tissue engineered skin may prove beneficial in promoting normal wound healing over pathologic healing.

  5. Expression of mesenchymal stem cell marker CD90 on dermal sheath cells of the anagen hair follicle in canine species.

    PubMed

    Mercati, F; Pascucci, L; Ceccarelli, P; Dall'Aglio, C; Pedini, V; Gargiulo, A M

    2009-09-23

    The dermal sheath (DS) of the hair follicle is comprised by fibroblast-like cells and extends along the follicular epithelium, from the bulb up to the infundibulum. From this structure, cells with stem characteristics were isolated: they have a mesenchymal origin and express CD90 protein, a typical marker of mesenchymal stem cells. It is not yet really clear in which region of hair follicle these cells are located but some experimental evidence suggests that dermal stem cells are localized prevalently in the lower part of the anagen hair follicle. As there are no data available regarding DS stem cells in dog species, we carried out a morphological analysis of the hair follicle DS and performed both an immunohistochemical and an immunocytochemical investigation to identify CD90+ cells. We immunohistochemically evidenced a clear and abundant positivity to CD90 protein in the DS cells located in the lower part of anagen hair follicle. The positive cells showed a typical fibroblast-like morphology. They were flat and elongated and inserted among bundles of collagen fibres. The whole structure formed a close and continuous sleeve around the anagen hair follicle. Our immunocytochemical study allowed us to localize CD90 protein at the cytoplasmic membrane level.

  6. Configurational effects of collagen/ALP coatings on enzyme immobilization and surface mineralization

    NASA Astrophysics Data System (ADS)

    Bosco, R.; Leeuwenburgh, S. C. G.; Jansen, J. A.; van den Beucken, J. J. J. P.

    2014-08-01

    The ultimate goal for surface modifications in bone implants is to achieve biologically active surface able to control and trigger specific tissue response. In this study was evaluated the effects of organic compound, derived from extracellular matrix, involved in tissue mineralization. Alkaline phosphatase (ALP) plays a fundamental role in bone mineralization concurrently with collagen, the main organic components of bones. Electrospray deposition (ESD) was used to coat titanium disks with ALP and collagen at room temperature. To verify the synergistic role of ALP and collagen different conformations of coatings (mixed and layered) were obtained and their mineralization capacity was tested in vitro. The mineralization tests indicated the fundamental role of collagen to increase ALP coating retention. Analyses indicated that the coating conformation has a role; in fact the mixed group showed improved ALP retention, enzymatic activity and unique mineralized surface morphology. ESD demonstrated to be a successful method to deposit organic molecules preserving their properties as indicated by the in vitro results. These findings proved the synergistic effect of ALP and collagen in inducing mineralization offering an intriguing coating constituent for medical device that aim to trigger surface mineralization such as bone implants.

  7. 3D printing of composite calcium phosphate and collagen scaffolds for bone regeneration.

    PubMed

    Inzana, Jason A; Olvera, Diana; Fuller, Seth M; Kelly, James P; Graeve, Olivia A; Schwarz, Edward M; Kates, Stephen L; Awad, Hani A

    2014-04-01

    Low temperature 3D printing of calcium phosphate scaffolds holds great promise for fabricating synthetic bone graft substitutes with enhanced performance over traditional techniques. Many design parameters, such as the binder solution properties, have yet to be optimized to ensure maximal biocompatibility and osteoconductivity with sufficient mechanical properties. This study tailored the phosphoric acid-based binder solution concentration to 8.75 wt% to maximize cytocompatibility and mechanical strength, with a supplementation of Tween 80 to improve printing. To further enhance the formulation, collagen was dissolved into the binder solution to fabricate collagen-calcium phosphate composites. Reducing the viscosity and surface tension through a physiologic heat treatment and Tween 80, respectively, enabled reliable thermal inkjet printing of the collagen solutions. Supplementing the binder solution with 1-2 wt% collagen significantly improved maximum flexural strength and cell viability. To assess the bone healing performance, we implanted 3D printed scaffolds into a critically sized murine femoral defect for 9 weeks. The implants were confirmed to be osteoconductive, with new bone growth incorporating the degrading scaffold materials. In conclusion, this study demonstrates optimization of material parameters for 3D printed calcium phosphate scaffolds and enhancement of material properties by volumetric collagen incorporation via inkjet printing.

  8. 3D Printing of Composite Calcium Phosphate and Collagen Scaffolds for Bone Regeneration

    PubMed Central

    Inzana, Jason A.; Olvera, Diana; Fuller, Seth M.; Kelly, James P.; Graeve, Olivia A.; Schwarz, Edward M.; Kates, Stephen L.; Awad, Hani A.

    2014-01-01

    Low temperature 3D printing of calcium phosphate scaffolds holds great promise for fabricating synthetic bone graft substitutes with enhanced performance over traditional techniques. Many design parameters, such as the binder solution properties, have yet to be optimized to ensure maximal biocompatibility and osteoconductivity with sufficient mechanical properties. This study tailored the phosphoric acid-based binder solution concentration to 8.75 wt% to maximize cytocompatibility and mechanical strength, with a supplementation of Tween 80 to improve printing. To further enhance the formulation, collagen was dissolved into the binder solution to fabricate collagen-calcium phosphate composites. Reducing the viscosity and surface tension through a physiologic heat treatment and Tween 80, respectively, enabled reliable thermal inkjet printing of the collagen solutions. Supplementing the binder solution with 1–2 wt% collagen significantly improved maximum flexural strength and cell viability. To assess the bone healing performance, we implanted 3D printed scaffolds into a critically sized murine femoral defect for 9 weeks. The implants were confirmed to be osteoconductive, with new bone growth incorporating the degrading scaffold materials. In conclusion, this study demonstrates optimization of material parameters for 3D printed calcium phosphate scaffolds and enhancement of material properties by volumetric collagen incorporation via inkjet printing. PMID:24529628

  9. Nanomechanics of Type I Collagen.

    PubMed

    Varma, Sameer; Orgel, Joseph P R O; Schieber, Jay D

    2016-07-12

    Type I collagen is the predominant collagen in mature tendons and ligaments, where it gives them their load-bearing mechanical properties. Fibrils of type I collagen are formed by the packing of polypeptide triple helices. Higher-order structures like fibril bundles and fibers are assembled from fibrils in the presence of other collagenous molecules and noncollagenous molecules. Curiously, however, experiments show that fibrils/fibril bundles are less resistant to axial stress compared to their constituent triple helices-the Young's moduli of fibrils/fibril bundles are an order-of-magnitude smaller than the Young's moduli of triple helices. Given the sensitivity of the Young's moduli of triple helices to solvation environment, a plausible explanation is that the packing of triple helices into fibrils perhaps reduces the Young's modulus of an individual triple helix, which results in fibrils having smaller Young's moduli. We find, however, from molecular dynamics and accelerated conformational sampling simulations that the Young's modulus of the buried core of the fibril is of the same order as that of a triple helix in aqueous phase. These simulations, therefore, suggest that the lower Young's moduli of fibrils/fibril bundles cannot be attributed to the specific packing of triple helices in the fibril core. It is not the fibril core that yields initially to axial stress. Rather, it must be the portion of the fibril exposed to the solvent and/or the fibril-fibril interface that bears the initial strain. Overall, this work provides estimates of Young's moduli and persistence lengths at two levels of collagen's structural assembly, which are necessary to quantitatively investigate the response of various biological factors on collagen mechanics, including congenital mutations, posttranslational modifications and ligand binding, and also engineer new collagen-based materials.

  10. [Occipital dermal sinus associated to a cerebellar abscess. Case].

    PubMed

    Costa, J M; de Reina, L; Guillén, A; Claramunt, E

    2004-10-01

    Congenital dermal sinuses are tubular tracts which communicate the skin with deeper structures. It is a manifestation of defective separation of the ectoderm and neuroderm. The incidence is 1/2500-3000 births alive. Almost 10 % of congenital dermal sinuses are localized in the occipitocervical region. They are usually asymptomatic, unless an infectious process is concurrent (meningitis, abscess). We are presenting the case of a 12 months girl with unnoticed cutaneous stigmata in the occipital region, who was admitted with a meningeal syndrome and secondary neurological impairment. She had a cerebellar abscess and was treated with decompression by puncture of the abscess and antibiotics. When infection was resolved, congenital dermal sinus was excised. Process solves without morbidity. We reviewed the clinical and therapeutic features in cases reported previously in the literature.

  11. Pesticides re-entry dermal exposure of workers in greenhouses.

    PubMed

    Caffarelli, V; Conte, E; Correnti, A; Gatti, R; Musmeci, F; Morali, G; Spagnoli, G; Tranfo, G; Triolo, L; Vita, M; Zappa, G

    2004-01-01

    This research has the aim to evaluate the risk of pesticide dermal exposure for workers in greenhouses. We considered the following crops: tomato, cucumber and strawberry, largely spread in Bracciano lake district. The pesticides monitored were: tetradifon on strawberry: metalaxyl, azoxystrobin and fenarimol on cucumber; acrinathrin, azoxystrobin and chlorpyrifos ethyl on tomato. The dermal exposure was evaluated by Dislodgeable Foliar Residue (DFR) measurements employing transfer coefficients got from literature. For risk evaluation, we have compared the dermal exposures with Acceptable Operator Exposure Levels (AOEL). The re-entry time were obtained intercepting the dose decay curves with AOEL values. The re-entry times result higher than two days in the cases of chlorpyrifos on tomato (re-entry time: 3 days), azoxystrobin on tomato (4 days), and tetradifon on strawberry (8 days). The need of measuring specific transfer coefficients is pointed out.

  12. The Relationship of Myocardial Collagen Metabolism and Reverse Remodeling after Cardiac Resynchronization Therapy

    PubMed Central

    Stankovic, Ivan; Milasinovic, Goran; Nikcevic, Gabrijela; Kircanski, Bratislav; Jovanovic, Velibor; Raspopovic, Srdjan; Radovanovic, Nikola; Pavlovic, Sinisa U.

    2016-01-01

    Summary Background In the majority of patients with a wide QRS complex and heart failure resistant to optimal medical therapy, cardiac resynchronization therapy (CRT) leads to reverse ventricular remodeling and possibly to changes in cardiac collagen synthesis and degradation. We investigated the relationship of biomarkers of myocardial collagen metabolism and volumetric response to CRT. Methods We prospectively studied 46 heart failure patients (mean age 61±9 years, 87% male) who underwent CRT implantation. Plasma concentrations of amino-terminal propeptide type I (PINP), a marker of collagen synthesis, and carboxy-terminal collagen telopeptide (CITP), a marker of collagen degradation, were measured before and 6 months after CRT. Response to CRT was defined as 15% or greater reduction in left ventricular end-systolic volume at 6-month follow-up. Results Baseline PINP levels showed a negative correlation with both left ventricular end-diastolic volume (r=-0.51; p=0.032), and end-systolic diameter (r=-0.47; p=0.049). After 6 months of device implantation, 28 patients (61%) responded to CRT. No significant differences in the baseline levels of PINP and CITP between responders and nonresponders were observed (p>0.05 for both). During follow-up, responders demonstrated a significant increase in serum PINP level from 31.37±18.40 to 39.2±19.19 μg/L (p=0.049), whereas in non-responders serum PINP levels did not significantly change (from 28.12±21.55 to 34.47± 18.64 μg/L; p=0.125). There were no significant changes in CITP levels in both responders and non-responders (p>0.05). Conclusions Left ventricular reverse remodeling induced by CRT is associated with an increased collagen synthesis in the first 6 months of CRT implantation.

  13. Cardiac findings in Quarter Horses with heritable equine regional dermal asthenia.

    PubMed

    Brinkman, Erin L; Weed, Benjamin C; Patnaik, Sourav S; Brazile, Bryn L; Centini, Ryan M; Wills, Robert W; Olivier, Bari; Sledge, Dodd G; Cooley, Jim; Liao, Jun; Rashmir-Raven, Ann M

    2017-03-01

    OBJECTIVE To compare biomechanical and histologic features of heart valves and echocardiographic findings between Quarter Horses with and without heritable equine regional dermal asthenia (HERDA). DESIGN Prospective case-control study. ANIMALS 41 Quarter Horses. PROCEDURES Ultimate tensile strength (UTS) of aortic and mitral valve leaflets was assessed by biomechanical testing in 5 horses with HERDA and 5 horses without HERDA (controls). Histologic evaluation of aortic and mitral valves was performed for 6 HERDA-affected and 3 control horses. Echocardiography was performed in 14 HERDA-affected and 11 control horses. Biomechanical data and echocardiographic variables of interest were compared between groups by statistical analyses, RESULTS Mean values for mean and maximum UTS of heart valves were significantly lower in HERDA-affected horses than in controls. Blood vessels were identified in aortic valve leaflets of HERDA-affected but not control horses. Most echocardiographic data did not differ between groups. When the statistical model for echocardiographic measures was controlled for body weight, mean and maximum height and width of the aorta at the valve annulus in short-axis images were significantly associated with HERDA status and were smaller for affected horses. CONCLUSIONS AND CLINICAL RELEVANCE Lower UTS of heart valves in HERDA-affected horses, compared with those of control horses, supported that tissues other than skin with high fibrillar collagen content are abnormal in horses with HERDA. Lack of significant differences in most echocardiographic variables between affected and control horses suggested that echocardiography may not be useful to detect a substantial loss of heart valve tensile strength. Further investigation is warranted to confirm these findings. Studies in horses with HERDA may provide insight into cardiac abnormalities in people with collagen disorders.

  14. Chondrogenesis of Human Infrapatellar Fat Pad Stem Cells on Acellular Dermal Matrix

    PubMed Central

    Ye, Ken; Traianedes, Kathy; Choong, Peter F. M.; Myers, Damian E.

    2016-01-01

    Acellular dermal matrix (ADM) has been in clinical use for decades in numerous surgical applications. The ability for ADM to promote cellular repopulation, revascularisation and tissue regeneration is well documented. Adipose stem cells have the ability to differentiate into mesenchymal tissue types, including bone and cartilage. The aim of this study was to investigate the potential interaction between ADM and adipose stem cells in vitro using TGFβ3 and BMP6. Human infrapatellar fat pad-derived adipose stem cells (IPFP-ASC) were cultured with ADM derived from rat dermis in chondrogenic (TGFβ3 and BMP6) medium in vitro for 2 and 4 weeks. Histology, qPCR, and immunohistochemistry were performed to assess for markers of chondrogenesis (collagen Type II, SOX9 and proteoglycans). At 4 weeks, cell-scaffold constructs displayed cellular changes consistent with chondrogenesis, with evidence of stratification of cell layers and development of a hyaline-like cartilage layer superficially, which stained positively for collagen Type II and proteoglycans. Significant cell–matrix interaction was seen between the cartilage layer and the ADM itself with seamless integration between each layer. Real time qPCR showed significantly increased COL2A1, SOX9, and ACAN gene expression over 4 weeks when compared to control. COL1A2 gene expression remained unchanged over 4 weeks. We believe that the principles that make ADM versatile and successful for tissue regeneration are applicable to cartilage regeneration. This study demonstrates in vitro the ability for IPFP-ASCs to undergo chondrogenesis, infiltrate, and interact with ADM. These outcomes serve as a platform for in vivo modelling of ADM for cartilage repair. PMID:26858950

  15. Enhanced stabilization of collagen by furfural.

    PubMed

    Lakra, Rachita; Kiran, Manikantan Syamala; Usha, Ramamoorthy; Mohan, Ranganathan; Sundaresan, Raja; Korrapati, Purna Sai

    2014-04-01

    Furfural (2-furancarboxaldehyde), a product derived from plant pentosans, has been investigated for its interaction with collagen. Introduction of furfural during fibril formation enhanced the thermal and mechanical stability of collagen. Collagen films treated with furfural exhibited higher denaturation temperature (Td) (p<0.04) and showed a 3-fold increase in Young's modulus (p<0.04) at higher concentration. Furfural and furfural treated collagen films did not have any cytotoxic effect. Rheological characterization showed an increase in shear stress and shear viscosity with increasing shear rate for treated collagen. Circular dichroism (CD) studies indicated that the furfural did not have any impact on triple helical structure of collagen. Scanning electron microscopy (SEM) of furfural treated collagen exhibited small sized porous structure in comparison with untreated collagen. Thus this study provides an alternate ecologically safe crosslinking agent for improving the stability of collagen for biomedical and industrial applications.

  16. Carbofuran occupational dermal toxicity, exposure and risk assessment†

    PubMed Central

    Gammon, Derek W; Liu, Zhiwei; Becker, John M

    2012-01-01

    BACKGROUND Carbofuran is a carbamate insecticide that inhibits AChE. Although toxic by ingestion in mammals, it has low dermal toxicity, with relatively few confirmed worker illnesses. This risk assessment describes its time of onset, time to peak effect and time to recovery in rats using brain AChE inhibition in acute and 21 day dermal studies; in vitro rat/human relative dermal absorption for granular (5G) and liquid (4F) formulations; occupational exposure estimates using the Pesticide Handlers' Exposure Database and Agricultural Handlers' Exposure Database (PHED/AHED). RESULTS The point of departure for acute risk calculation (BMDL10) was 6.7 mg kg−1 day−1 for brain AChE inhibition after 6 h exposure. In a 21 day study, the BMDL10 was 6.8 mg kg−1 day−1, indicating reversibility. At 75 mg kg−1 day−1, time of onset was ≤30 min and time to peak effect was 6–12 h. Rat skin had ca tenfold greater dermal absorption of carbofuran (Furadan® 5G or 4F) than human skin. Exposure estimates for 5G in rice and 4F in ten crops had adequate margins of exposure (>100). CONCLUSION Rat dermal carbofuran toxicity was assessed in terms of dose and time-related inhibition of AChE. Comparative dermal absorption in rats was greater than in humans. Worker exposure estimates indicated acceptable risk for granular and liquid formulations of carbofuran. Copyright © 2011 Society of Chemical Industry PMID:21834090

  17. Dermal absorption of mucopolysaccharide polysulfate (heparinoid) in human and minipig.

    PubMed

    Kumokawa, Tadao; Hirata, Kazumasa; Sato, Keiichi; Kano, Satoshi

    2011-01-01

    Dermal absorption of mucopolysaccharide polysulfate (MPS, the active ingredient of Hirudoid") in human and minipig was investigated by using 14C-labeled MPS. Three types of human and minipig skin samples were used: intact, dried and tape-stripped. At 24 h after application of 14C-MPS to intact human skin on a Franz cell in vitro, the radioactivity was detected in 0.98, 1.34, and 0.08% of the applied dose in stratum corneum, epidermal-dermal skin, and receptor fluid, respectively. In dried human skin, the amount of radioactivity detected was similar to that in intact human skin. By contrast, in tape-stripped human skin, higher radioactivity was detected in epidermal-dermal skin and receptor fluid (2.85 and 0.33% of the applied dose, respectively) than in intact or dried skin. Minipig skin showed 1.5 to 4.5 times greater dermal absorption of 14C-MPS, as compared with human skin. In an in vivo study with minipig, radioactivity was detected at the dosing skin site after dermal administration of 14C-MPS. The stability of 14C-MPS in human skin after dermal application was evaluated by agarose gel electrophoresis and ion-exchange chromatography. It was suggested that 14C-MPS absorbed into human skin would be stable because the chromatogram behaviors of the radioactivity on the two types of method were not shifted. Microautoradiography of human and minipig skins after 14C-MPS dosing showed that radioactivity was widely distributed in the epidermis in the area near hair follicles. The present results clearly demonstrate that MPS is stable and that a small fraction of it is percutaneously absorbed by human and minipig skin.

  18. Comparative evaluation of a biomimic collagen/hydroxyapatite/β-tricaleium phosphate scaffold in alveolar ridge preservation with Bio-Oss Collagen

    NASA Astrophysics Data System (ADS)

    Wang, Tong; Li, Qing; Zhang, Gui-feng; Zhou, Gang; Yu, X