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

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 results suggest that microporous electrospun scaffolds pre-seeded with fibroblasts promote greater wound-healing than acellular scaffolds.     

Antitrichomonadal and other biological effects of sugar hydrazones and phenylosazones

When investigating the possible antitrichomodal effect of 41 phenylsazones, nitro-and dinitrophenylhydrazones a significant inhibitory effect on multiplication ofTrichomonas foetus could be detected in 14 derivatives; eight derivatives were ineffective, other derivatives exhibited only a alight effect. The inhibitory effect of most compounds increased after acetylation. Toxicity of seven effective compounds was determinedin vivo. Mutagenicity of these compounds was followed with microorganisms and their cytotoxicity with tumor EAC cells. Two of the effective compounds exhibited also a significant mutagenic effect, three of eight compounds had a pronounced cytotoxic effect, three of eight compounds had a pronounced cytotoxic effectin vitro on the EAC cells, in which they inhibited mainly the incorporation of adenine.     

Photobiomodulation of a flowable matrix in a human skin ex vivo model demonstrates energy‐based enhancement of engraftment integration and remodeling

The use of dermal substitutes to treat skin defects such as ulcers has shown promising results, suggesting a potential role for skin substitutes for treating acute and chronic wounds. One of the main drawbacks with the use of dermal substitutes is the length of time from engraftment to graft take, plus the risk of contamination and failure due to this prolonged integration. Therefore, the use of adjuvant energy‐based therapeutic modalities to augment and accelerate the rate of biointegration by dermal substitute engraftments is a desirable outcome. The photobiomodulation (PBM) therapy modulates the repair process, by stimulating cellular proliferation and angiogenesis. Here, we evaluated the effect of PBM on a collagen‐glycosaminoglycan flowable wound matrix (FWM) in an ex vivo human skin wound model. PBM resulted in accelerated rate of re‐epithelialization and organization of matrix as seen by structural arrangement of collagen fibers, and a subsequent increased expression of alpha‐smooth muscle actin (α‐SMA) and vascular endothelial growth factor A (VEGF‐A) leading to an overall improved healing process. The use of PBM promoted a beneficial effect on the rate of integration and healing of FWM. We therefore propose that the adjuvant use of PBM may have utility in enhancing engraftment and tissue repair and be of value in clinical practice.      

Mesenchymal stromal cell‐derived factors promote the colonization of collagen 3D scaffolds with human skin cells

The development of stem cell technology in combination with advances in biomaterials has opened new ways of producing engineered tissue substitutes. In this study, we investigated whether the therapeutic potential of an acellular porous scaffold made of type I collagen can be improved by the addition of a powerful trophic agent in the form of mesenchymal stromal cells conditioned medium (MSC‐CM) in order to be used as an acellular scaffold for skin wound healing treatment. Our experiments showed that MSC‐CM sustained the adherence of keratinocytes and fibroblasts as well as the proliferation of keratinocytes. Moreover, MSC‐CM had chemoattractant properties for keratinocytes and endothelial cells, attributable to the content of trophic and pro‐angiogenic factors. Also, for the dermal fibroblasts cultured on collagen scaffold in the presence of MSC‐CM versus serum control, the ratio between collagen III and I mRNAs increased by 2‐fold. Furthermore, the gene expression for α‐smooth muscle actin, tissue inhibitor of metalloproteinase‐1 and 2 and matrix metalloproteinase‐14 was significantly increased by approximately 2‐fold. In conclusion, factors existing in MSC‐CM improve the colonization of collagen 3D scaffolds, by sustaining the adherence and proliferation of keratinocytes and by inducing a pro‐healing phenotype in fibroblasts.     

Cytotoxicity testing of burn wound dressings: first results

Topical antimicrobial therapy represents an essential part of burn wound care. In order to prevent and treat burn wound infection dressings with antimicrobial properties are applied directly on the wound surface. Not only the infection control but also promotion of healing is very important in burn wound management. It is well known, that a dressing in bactericidal concentration might also delay wound healing. This study was aimed to evaluate the potential toxic effect of topical antimicrobial agents on murine and human dermal cells. For toxicity testing the method by Vittekova et al. was used to evaluate potential toxic effects of 16 agents and 6 control samples on two in vitro cultured cell systems [3T3 cells and dermal fibroblasts] during the first 24 h. Following the 24 h cell culture with the tested agents the live cell counts were evaluated. According to results obtained on both cell systems, the tested samples were divided into three groups—nontoxic, semi-toxic and toxic. Nontoxic samples included Acetic acid 1%, Acticoat^®, Dermacyn^®, Framykoin^®, Silverlon^®, gauze, acellular human allodermis and acellular porcine xenodermis. Semi-toxic group included Algivon^®Plus, Aquacel^®Ag, Betadine^®, Nitrofurazone, Octenisept^®, Suprasorb^® A and a porcine dermal scaffold Xeno-Impl. Finally, the toxic group included Algivon^®, Dermazin^®, Ialugen^®Plus, Prontoderm^®, Suprasorb^® A Ag and 20% SDS. As the preliminary results of this study have shown, our findings may serve as a potential guide to selection of the most appropriate topical antimicrobial dressings for treatmet of burns. However before they can be translated into clinical practice recommendations, more research on antimicrobial dressings cytotoxicity testing will be necessary.     

Characterization of a new degradable polymer scaffold for regeneration of the dermis: In vitro and in vivo human studies

Full thickness skin wounds in humans heal with scars, but without regeneration of the dermis. A degradable poly(urethane urea) scaffold (PUUR), Artelon® is already used to reinforce soft tissues in orthopaedics, and for treatment of osteoarthritis of the hand, wrist and foot. In this paper we have done in vitro experiments followed by in vivo studies to find out whether the PUUR is biocompatible and usable as a template for dermal regeneration. Human dermal fibroblasts were cultured on discs of PUUR, with different macrostructures (fibrous and porous). They adhered to and migrated into the scaffolds, and produced collagen. The porous scaffold was judged more suitable for clinical applications and 4 mm Ø, 2 mm-thick discs of porous scaffold (12% w/w or 9% w/w polymer solution) were inserted intradermally in four healthy human volunteers. The implants were well tolerated and increasing ingrowth of fibroblasts was seen over time in all subjects. The fibroblasts stained immunohistochemically for procollagen and von Willebrand factor, indicating neocollagenesis and angiogenesis within the scaffolds. The PUUR scaffold may be a suitable material to use as a template for dermal regeneration.Key words: dermal regeneration, tissue engineering, polymer scaffold, wound healing, in vitro, in vivo, guided tissue regeneration, human, burns     

Antioxidants protect keratinocytes against M. ulcerans mycolactone cytotoxicity

Background

Mycobacterium ulcerans is the causative agent of necrotizing skin ulcerations in distinctive geographical areas. M. ulcerans produces a macrolide toxin, mycolactone, which has been identified as an important virulence factor in ulcer formation. Mycolactone is cytotoxic to fibroblasts and adipocytes in vitro and has modulating activity on immune cell functions. The effect of mycolactone on keratinocytes has not been reported previously and the mechanism of mycolactone toxicity is presently unknown. Many other macrolide substances have cytotoxic and immunosuppressive activities and mediate some of their effects via production of reactive oxygen species (ROS). We have studied the effect of mycolactone in vitro on human keratinocytes—key cells in wound healing—and tested the hypothesis that the cytotoxic effect of mycolactone is mediated by ROS.

Methodology/Principal Findings

The effect of mycolactone on primary skin keratinocyte growth and cell numbers was investigated in serum free growth medium in the presence of different antioxidants. A concentration and time dependent reduction in keratinocyte cell numbers was observed after exposure to mycolactone. Several different antioxidants inhibited this effect partly. The ROS inhibiting substance deferoxamine, which acts via chelation of Fe²⁺, completely prevented mycolactone mediated cytotoxicity.

Conclusions/Significance

This study demonstrates that mycolactone mediated cytotoxicity can be inhibited by deferoxamine, suggesting a role of iron and ROS in mycolactone induced cytotoxicity of keratinocytes. The data provide a basis for the understanding of Buruli ulcer pathology and the development of improved therapies for this disease.     

The stimulatory effects of alpha1-adrenergic receptors on TGF-beta1, IGF-1 and hyaluronan production in human skin fibroblasts

Skin fibroblasts modulate tissue repair, wound healing and immunological responses. Adrenergic receptors (ARs) mediate important physiological functions, such as endocrine, metabolic and neuronal activity. In this study, the expression α1A-ARs in human skin fibroblasts is examined and verified. Regulatory effects of α1-agonist cirazoline on cell migration and the production of transforming growth factor β1 (TGF-β1), insulin-like growth factor 1 (IGF-1), hyaluronan (HA), fibronectin and procollagen type I carboxy-terminal peptide (PIP) by human skin fibroblasts are assessed and validated. α1A-AR mRNA and protein were found in human skin fibroblasts WS1. Exposure of cirazoline doubled skin fibroblast migration and the increase in cell migration was attenuated by α1-antagonist prazosin. TGF-β1 mRNA and production were enhanced after exposure to cirazoline and IGF-1 production was also increased after treatment with cirazoline. Exposure to cirazoline also enhanced HA and PIP production. The increases in TGF-β1, IGF-1, HA and PIP production were partially abolished in fibroblasts transfected with α1A-AR short interfering RNAs, indicating that α1A-ARs are involved in the cirazoline-induced increases in TGF-β1, IGF-1, HA and PIP production. Thus, α1A-ARs are stably expressed and stimulate cell migration and TGF-β1, IGF-1, HA and PIP production in human skin fibroblasts. Moreover, TGF-β1, IGF-1, HA and PIP production and the cell migration of human skin fibroblasts are possibly modulated by natural catecholamines produced by the endocrine system or sympathetic innervation, which could directly or indirectly participate in cytokine secretion, fibroblast migration and matrix production of wound healing in the skin.     

Characterization of Hair Follicle Development in Engineered Skin Substitutes

Generation of skin appendages in engineered skin substitutes has been limited by lack of trichogenic potency in cultured postnatal cells. To investigate the feasibility and the limitation of hair regeneration, engineered skin substitutes were prepared with chimeric populations of cultured human keratinocytes from neonatal foreskins and cultured murine dermal papilla cells from adult GFP transgenic mice and grafted orthotopically to full-thickness wounds on athymic mice. Non-cultured dissociated neonatal murine-only skin cells, or cultured human-only skin keratinocytes and fibroblasts without dermal papilla cells served as positive and negative controls respectively. In this study, neonatal murine-only skin substitutes formed external hairs and sebaceous glands, chimeric skin substitutes formed pigmented hairs without sebaceous glands, and human-only skin substitutes formed no follicles or glands. Although chimeric hair cannot erupt readily, removal of upper skin layer exposed keratinized hair shafts at the skin surface. Development of incomplete pilosebaceous units in chimeric hair corresponded with upregulation of hair-related genes, LEF1 and WNT10B, and downregulation of a marker of sebaceous glands, Steroyl-CoA desaturase. Transepidermal water loss was normal in all conditions. This study demonstrated that while sebaceous glands may be involved in hair eruption, they are not required for hair development in engineered skin substitutes.     

Evaluation of Dermal Substitute in a Novel Co-Transplantation Model with Autologous Epidermal Sheet

The development of more and more new dermal substitutes requires a reliable and effective animal model to evaluate their safety and efficacy. In this study we constructed a novel animal model using co-transplantation of autologous epidermal sheets with dermal substitutes to repair full-thickness skin defects. Autologous epidermal sheets were obtained by digesting the basement membrane (BM) and dermal components from rat split-thickness skins in Dispase II solution (1.2 u/ml) at 4°C for 8, 10 and 12 h. H&E, immunohistochemical and live/dead staining showed that the epidermal sheet preserved an intact epidermis without any BM or dermal components, and a high percentage of viable cells (92.10±4.19%) and P63 positive cells (67.43±4.21%) under an optimized condition. Porcine acellular dermal matrixes were co-transplanted with the autologous epidermal sheets to repair full-thickness skin defects in Sprague-Dawley rats. The epidermal sheets survived and completely re-covered the wounds within 3 weeks. Histological staining showed that the newly formed stratified epidermis attached directly onto the dermal matrix. Inflammatory cell infiltration and vascularization of the dermal matrix were not significantly different from those in the subcutaneous implantation model. Collagen IV and laminin distributed continuously at the epidermis and dermal matrix junction 4 weeks after transplantation. Transmission electron microscopy further confirmed the presence of continuous lamina densa and hemidesmosome structures. This novel animal model can be used not only to observe the biocompatibility of dermal substitutes, but also to evaluate their effects on new epidermis and BM formation. Therefore, it is a simple and reliable model for evaluating the safety and efficacy of dermal substitutes.     

Acellularization-Induced Changes in Tensile Properties Are Organ Specific - An In-Vitro Mechanical and Structural Analysis of Porcine Soft Tissues

Introduction

Though xenogeneic acellular scaffolds are frequently used for surgical reconstruction, knowledge of their mechanical properties is lacking. This study compared the mechanical, histological and ultrastructural properties of various native and acellular specimens.

Materials and Methods

Porcine esophagi, ureters and skin were tested mechanically in a native or acellular condition, focusing on the elastic modulus, ultimate tensile stress and maximum strain. The testing protocol for soft tissues was standardized, including the adaption of the tissue’s water content and partial plastination to minimize material slippage as well as templates for normed sample dimensions and precise cross-section measurements. The native and acellular tissues were compared at the microscopic and ultrastructural level with a focus on type I collagens.

Results

Increased elastic modulus and ultimate tensile stress values were quantified in acellular esophagi and ureters compared to the native condition. In contrast, these values were strongly decreased in the skin after acellularization. Acellularization-related decreases in maximum strain were found in all tissues. Type I collagens were well-preserved in these samples; however, clotting and a loss of cross-linking type I collagens was observed ultrastructurally. Elastins and fibronectins were preserved in the esophagi and ureters. A loss of the epidermal layer and decreased fibronectin content was present in the skin.

Discussion

Acellularization induces changes in the tensile properties of soft tissues. Some of these changes appear to be organ specific. Loss of cross-linking type I collagen may indicate increased mechanical strength due to decreasing transverse forces acting upon the scaffolds, whereas fibronectin loss may be related to decreased load-bearing capacity. Potentially, the alterations in tissue mechanics are linked to organ function and to the interplay of cells and the extracellular matrix, which is different in hollow organs when compared to skin.     

Fibroblasts play a regulatory role in the control of pigmentation in reconstructed human skin from skin types I and II

Human melanocytes in monolayer culture are extremely dependent on a wide range of soluble signals for their proliferation and melanogenesis. The advent of three-dimensional models of reconstructed skin allows one to ask questions of how these cells are regulated within a setting which more closely approximates normal skin. The purpose of this study was to investigate to what extent melanocytes within a reconstructed skin model are sensitive to regulation by dermal fibroblasts, basement membrane (BM) proteins and the addition of alpha-melanocyte-stimulating hormone (alpha-MSH). Sterilized acellular de-epidermized dermis (prepared to retain BM proteins or deliberately denuded of BM by enzymatic treatment) from skin type I or II was reconstituted with fibroblasts, melanocytes and keratinocytes. In all but one case (9/10), cell donors were skin type I or II. The presence of BM antigens was found to be necessary for positional orientation of the melanocytes; in the absence of BM, melanocytes moved into the upper keratinocyte layer pigmenting spontaneously. Addition of fibroblasts suppressed the extent of spontaneous pigmentation of melanocytes within this model. Neither alpha-MSH nor cholera toxin induced pigmentation in this model despite the fact that melanocytes clearly had the ability to synthesize pigment.     

Enrichment of epidermal stem cells by rapid adherence and analysis of the reciprocal interaction of epidermal stem cells with neighboring cells using an organotypic system

Keratinocytes have the ability to adhere to extracellular matrix rapidly. With this in mind, in this study we isolated keratinocytes known as rapidly adhering (RA) cells. To compare epidermal regenerative abilities, skin substitutes were reconstructed by adding keratinocytes or RA cells to two groups of bioengineered dermis made by fibroblasts and hair follicle dermal cells respectively. After transplantation, the results illustrated that the skin substitutes including RA cells were integrated into the host tissue. Furthermore, with hair follicle dermal cells' influences, the RA cells could form structures very similar to normal hair follicles. These results indicate that RA cells are predominately comprised of epidermal stem cells. The results also demonstrated that besides the reciprocal interaction of epidermal stem cells with dermal cells, the interaction of epidermal stem cells with keratinocytes were critical in epidermis morphogenesis and self-renewal, and application of RA cells could optimize engineering of skin substitutes.     

Selective inhibition of fibroblasts by spermine in primary cultures of normal human skin epithelial cells

Summary Overgrowth with fibroblasts has been a major problem in the cultivation of normal human skin epithelium. In the present study it is shown that the addition of spermine to the culture medium in micromolar concentrations has a differential cytotoxic effect on fibroblasts allowing the cultivation of human skin epithelial cells in primary culture without fibroblastic overgrowth. Putrescine, another polyamine, is shown to be equally cytotoxic to fibroblasts and epithelial cells when added in millimolar concentrations; below this concentration range no cytotoxic effect could be demonstrated. This difference in cytotoxicity between spermine and putrescine is suggested to depend on the conversion of spermine, but not putrescine, and to highly cytotoxic products by an amine oxidase present in fetal bovine serum. This project was supported by the Novo foundation.     

Wound healing mediator production by human dermal fibroblasts grown within a collagen-GAG matrix for skin repair in humans

Cell and tissue therapy applications in humans are being used increasingly, particularly for tissue repair. Several reconstructed skin models have been proposed. Wound healing involves overlapping steps of inflammation, cell migration and proliferation, neovascularisation, extracellular matrix production and remodelling. This is regulated by numerous cytokines and other soluble mediators. We have prepared dermal substitutes (DS) consisting of a collagen-GAG, three-dimensional matrix colonized by human dermal fibroblasts (HDF), isolated by skin explant or enzymatic digestion of the skin for potential therapeutic use in humans. To test the functionality of these DS, we measured (ELISA) the stimulatory effect on HDF in the matrix, of serial dilutions of human serum (HS) on the production of wound healing mediators: interleukin-8 (IL-8), vascular endothelial growth factor (VEGF), keratinocyte growth factor (KGF) and tissue inhibitor of metalloproteinase-1 (TIMP-1). We observed: 1). a stimulatory effect of HS on HDF production of the different mediators tested, with a dose-dependent effect in the case of IL-8 and VEGF. 2). A matrix-potentiating effect on the production of the different mediators by HDF. 3). A decrease in the production of IL-8 and VEGF when HDF isolated by enzymatic digestion was used to colonize the matrix as compared with HDF isolated by skin explant. We conclude: 1). that the production by HDF, in a collagen-GAG matrix, of mediators involved in cutaneous wound healing is decreased when HDF are isolated by enzymatic skin digestion rather than by skin explant. 2). That measurement of the production of cytokines or other mediators could be a useful quality control to test the functionality of tissue-engineered DS for tissue repair therapy in humans and more generally of cells prepared for cell therapy.     

Modulation of Activity of Known Cytotoxic Ruthenium(III) Compound (KP418) with Hampered Transmembrane Transport in Electrochemotherapy In Vitro and In Vivo

To increase electrochemotherapy (ECT) applicability, the effectiveness of new drugs is being tested in combination with electroporation. Among them two ruthenium(III) compounds, (imH)[trans-RuCl₄(im)(DMSO-S)] (NAMI-A) and Na[trans-RuCl₄(ind)₂] (KP1339), proved to possess increased antitumor effectiveness when combined with electroporation. The objective of our experimental work was to determine influence of electroporation on the cytotoxic and antitumor effect of a ruthenium(III) compound with hampered transmembrane transport, (imH)[trans-RuCl₄(im)₂] (KP418) in vitro and in vivo and to determine changes in metastatic potential of cells after ECT with KP418 in vitro. In addition, platinum compound cisplatin (CDDP) and ruthenium(III) compound NAMI-A were included in the experiments as reference compounds. Our results show that electroporation leads to increased cellular accumulation and cytotoxicity of KP418 in murine melanoma cell lines with low and high metastatic potential, B16-F1 and B16-F10, but not in murine fibrosarcoma cell line SA-1 in vitro which is probably due to variable effectiveness of ECT in different cell lines and tumors. Electroporation does not potentiate the cytotoxicity of KP418 as prominently as the cytotoxicity of CDDP. We also showed that the metastatic potential of cells which survived ECT with KP418 or NAMI-A does not change in vitro: resistance to detachment, invasiveness, and re-adhesion of cells after ECT is not affected. Experiments in murine tumor models B16-F1 and SA-1 showed that ECT with KP418 does not have any antitumor effect while ECT with CDDP induces significant dose-dependent tumor growth delay in the two tumor models used in vivo.     

Characterization of Smad3 knockout mouse derived skin cells

TGF-β plays an important role in skin wound healing process, in which Smad3 acts as a signaling molecule. Smad3 knockout mice exhibit enhanced wound healing and less inflammatory process, but the intrinsic properties of the mouse derived skin cells are generally unexplored. The purpose of this study is to characterize the biological behavior of skin cells derived from Smad3 knockout mice and thus to define the mechanism of this particular wound healing process. Keratinocytes and dermal fibroblasts were harvested from the skin of Smad3 knockout (Smad3 KO) and wild-type (WT) mice and in vitro cultured for one and two passages for various experiments. The results showed that KO mouse serum contained significantly higher levels of TGF-β1 and lower level of IL-6 and IL-10 than WT mouse serum (p < 0.05), which were also supported by the same findings of more TGF-β1 and less IL-6 and IL-10 in the supernatant of cultured KO dermal fibroblasts than those of WT cells (p < 0.05). At gene levels, IL-6, IL-10, and TGF-β1 were significantly less expressed in KO fibroblasts than in WT fibroblasts (p < 0.05). In addition, KO dermal fibroblasts also exhibited stronger migration and proliferation potentials than WT fibroblasts (p < 0.05). Moreover, both KO fibroblasts and keratinocytes showed higher colony-forming efficiency than WT counterparts with significant difference (p < 0.05). These findings indicate that both systemic factors and intrinsic properties of skin cells contribute to enhanced wound healing and less inflammatory reaction observed in Smad3 knock-out mice.     

口腔修复膜植入预防腮腺手术后Frey综合征

目的：观察口腔修复膜（异种脱细胞真皮基质）植入对腮腺术后Frey综合征的预防作用。方法：我科近五年来施行的腮腺手术病人共75例,其中35例选择在皮瓣与腮腺床之间植入口腔修复膜,术后随访1-2年,以患者主观症状判断是否存在Frey综合征。结果：在未使用口腔修复膜的患者中,有29例（72．5％）出现Frey综合征的症状,在使用修复膜的患者中只有1例（2．9％）出现症状。两组之间有显著性差异（P〈0．01）。结论：口腔修复膜（异种脱细胞真皮基质）能有效预防腮腺手术后Frey综合征的发生。     

Induction of MMP-9 release from human dermal fibroblasts by thrombin: involvement of JAK/STAT3 signaling pathway in MMP-9 release

Background:  

It has been recognized that dermal fibroblasts and matrix metalloproteases (MMP) play crucial roles in wound healing process in skin. Thrombin was found to stimulate IL-8 release from human dermal fibroblasts (HDFs). However, little is known of the effect of thrombin on secretion of MMPs from dermal fibroblasts. In the present study, the influence of thrombin on proMMP-2 and proMMP-9 activity release from primary cultured HDFs, and its potential signaling pathways were investigated.     

Differential cytotoxic acitivity of anticollagen serum on rat osteoblasts and fibroblasts in tissue culture.

Rat skin fibroblasts grown in tissue culture were lysed by anti-rat-tail collagen serum and antibodies to the ordered collagen-like synthetic polymer (Pro-Gly-Pro)-n. This cytotoxic effect is complement-dependent and occurs only if the fibroblasts were pretreated with trypsin. These anti-sera have very little cytotoxicity on cultured rat osteoblasts. This differential cytotoxicity is not due to differential binding of anticollagen serum to the cells. Both osteoblasts and skin fibroblasts bind the anticollagen serum as was demonstrated by fluorescent immunoglobulin.