Differential regulation of collagen, glycosaminoglycan, fibronectin, and collagenase activity production in cultured human adult dermal fibroblasts by interleukin 1-alpha and beta and tumor necrosis factor-alpha and beta

Glycosaminoglycans: Sweet as Sugar Targets for Topical Skin Anti-Aging

Glycosaminoglycans (GAGs) are long, linear polysaccharides comprised of repeating disaccharide units with pleiotropic biological functions, with the non-sulfated GAG hyaluronic acid (HA), and sulfated GAGs dermatan sulfate, chondroitin sulfate, heparan sulfate, keratan sulfate, and to a lesser extent heparin all being expressed in skin. Their ability to regulate keratinocyte proliferation and differentiation, inflammatory processes and extracellular matrix composition and quality demonstrates their critical role in regulating skin physiology. Similarly, the water-binding properties of GAGs and structural qualities, particularly for HA, are crucial for maintaining proper skin form and hydration. The biological importance of GAGs, as well as extensive evidence that their properties and functions are altered in both chronological and extrinsic skin aging, makes them highly promising targets to improve cosmetic skin quality. Within the present review, we examine the cutaneous biological activity of GAGs alongside the protein complexes they form called proteoglycans and summarize the age-related changes of these molecules in skin. We also examine current topical interventional approaches to modulate GAGs for improved skin quality such as direct exogenous administration of GAGs, with a particular interest in strategies targeted at potentiating GAG levels in skin through either attenuating GAG degradation or increasing GAG production.

Mesenchymal stem cell as a novel approach to systemic sclerosis; current status and future perspectives

Systemic sclerosis is a rare chronic autoimmune disease with extensive microvascular injury, damage of endothelial cells, activation of immune responses, and progression of tissue fibrosis in the skin and various internal organs. According to epidemiological data, women's populations are more susceptible to systemic sclerosis than men. Until now, various therapeutic options are employed to manage the symptoms of the disease. Since stem cell-based treatments have developed as a novel approach to rescue from several autoimmune diseases, it seems that stem cells, especially mesenchymal stem cells as a powerful regenerative tool can also be advantageous for systemic sclerosis treatment via their remarkable properties including immunomodulatory and anti-fibrotic effects. Accordingly, we discuss the contemporary status and future perspectives of mesenchymal stem cell transplantation for systemic sclerosis.

The Relationship between Autism and Ehlers-Danlos Syndromes/Hypermobility Spectrum Disorders

Considerable interest has arisen concerning the relationship between hereditary connective tissue disorders such as the Ehlers-Danlos syndromes (EDS)/hypermobility spectrum disorders (HSD) and autism, both in terms of their comorbidity as well as co-occurrence within the same families. This paper reviews our current state of knowledge, as well as highlighting unanswered questions concerning this remarkable patient group, which we hope will attract further scientific interest in coming years. In particular, patients themselves are demanding more research into this growing area of interest, although science has been slow to answer that call. Here, we address the overlap between these two spectrum conditions, including neurobehavioral, psychiatric, and neurological commonalities, shared peripheral neuropathies and neuropathologies, and similar autonomic and immune dysregulation. Together, these data highlight the potential relatedness of these two conditions and suggest that EDS/HSD may represent a subtype of autism.

Adipose-derived stromal/stem cells successfully attenuate the fibrosis of scleroderma mouse models

AIM

Systemic sclerosis (SSc) is an autoimmune disease characterized by skin and lung fibrosis. Although SSc has a high mortality risk, an effective treatment for the disease has not been established yet. Mesenchymal stromal/stem cells (MSCs) are multipotential nonhematopoietic progenitor cells that have the ability to regulate immune responses. Adipose-derived stromal/stem cells (ASCs), one of the types of MSCs, have the advantage of accessibility and potent immunomodulatory effects when compared with other MSCs, such as bone marrow-derived MSCs. This study aimed to investigate the antifibrotic effect of ASCs in scleroderma mouse models, including bleomycin-induced scleroderma and sclerodermatous chronic graft-versus-host disease (Scl-cGVHD) models.

METHOD

ASCs were intravenously administered to a bleomycin-induced scleroderma or Scl-cGVHD model on day 0. We compared the skin and lung fibrosis of scleroderma model mice between the ASC-treated group and control group.

RESULTS

Administration of ASCs attenuated the skin and lung fibrosis of bleomycin-induced scleroderma and Scl-cGVHD model mice compared to that in the control mice. Immunohistochemical staining showed that ASCs suppressed the infiltration of CD4⁺ , CD8⁺ T cells and macrophages into the dermis of bleomycin model mice compared to that in control mice. In addition, ASCs attenuated the messenger RNA expression of collagen and fibrogenic cytokines, such as interleukin (IL)-6 and IL-13, in the skin of bleomycin model mice. ASCs also reduced the frequency of fibrogenic cytokine-producing CD4⁺ T cells and effector B cells in the spleen of bleomycin model mice.

CONCLUSION

ASCs could prove to be a potential therapeutic agent for use in patients with SSc.

A Pilot Study on Ocular Safety and Efficacy of Infliximab as an Antifibrotic Agent After Experimental Glaucoma Filtration Surgery

Introduction

Tumor necrosis factor-α (TNF-α) is a multifunctional, proinflammatory cytokine that mediates pleiotropic biological functions, especially inflammation and immunoregulation. We hypothesized that blocking TNF-α with a monoclonal antibody would decrease inflammation and subconjunctival scarring in an animal model of experimental filtration surgery.

Methods

In a randomized, prospective, masked-observer study, 30 New Zealand albino rabbits underwent glaucoma filtration surgery. The animals were allocated to receive either intraoperative application of infliximab (group A) or mitomycin C (MMC) at a concentration of 0.2 mg/ml (group B) or balanced salt solution (BSS, control) (group C). Different infliximab doses, namely 1.0, 2.0, 3.0, 4.0, 5.0 mg in 0.1 ml, were applied. Bleb survival and characteristics were evaluated over a 30-day period. The animals were killed on postoperative day 15 or 30. Histology of the operated eyes was performed to evaluate and grade the amount of scarring in each group. Cellular density was evaluated in each case.

Results

Infliximab did not appear to improve outcomes in this model of glaucoma filtration surgery. Bleb survival was significantly higher in the MMC group compared to the other groups (p < 0.001 for both comparisons). Vascularity was also significantly lower in the MMC group compared to the other groups (p = 0.018 for both comparisons). There was a significant decrease in cellular density in the MMC group compared to the control (p = 0.0352) and the infliximab group (p < 001).

Conclusion

Our results have shown that trabeculectomies in the infliximab group failed faster and displayed more scarring, compared to the control and MMC groups. This outcome suggests that the infliximab doses used in this pilot study resulted in a subconjunctival TNF-α concentration, which acted as a stimulator to fibroblasts.

IL-1β-induced modulation of gene expression profile in human dermal fibroblasts: the effects of Thai herbal Sahatsatara formula, piperine and gallic acid possessing antioxidant properties

Background

Pain is the main symptom of most musculoskeletal disorders and can be caused by inflammation in association with oxidative stress. Thai herbal Sahatsatara formula (STF), a polyherbal formula, has been traditionally used for relieving muscle pain and limb numbness. This study aimed to investigate biologically active compounds of STF and its pharmacological effects related to antioxidant and anti-inflammatory activities.

Methods

The identification of possibly active compounds of STF was performed by high performance liquid chromatography (HPLC). Moreover, this study also assessed the free radical scavenging activities of STF and its components using DPPH radical scavenging assay and their inhibitory effects on IL-1β-induced intracellular reactive oxygen species (ROS) formation in primary human dermal fibroblasts (NHDFs) using DCFDA-flow cytometry analysis. Modulation of human gene expression by STF and its active compounds was investigated by microarray analyzed through Gene Ontology (GO) classification and pathway enrichment analysis.

Results

HPLC analysis has revealed the presence of gallic acid (GA) and piperine (PP) as the major compounds in STF extracts. Our finding discovered that STF and its active compounds (GA and PP) yielded free radical scavenging activities and abilities to inhibit IL-1β-induced cellular ROS formation in NHDFs. Furthermore, microarray analysis demonstrated that a total of 84 genes (54 upregulated and 30 downregulated) were significantly affected by IL-1β involved in inflammatory cytokines, chemokines, transcription factors, cell adhesion molecules and other immunomodulators participating in NF-κB signaling. The significantly upregulated genes in IL-1β-treated in NHDFs participate in interleukin and cholecystokinin (CCRK) signaling pathways. The GO analysis of the target genes showed that all test compounds including indomethacin, STF and its active compounds, can downregulate the genes involved in NF-кB signaling pathway in IL-1β-treated NHDFs compared to the cells treated with IL-1β alone.

Conclusions

STF and its active compounds possessing antioxidant actions can modulate the effects of IL-1β-mediated alteration of gene expression profiles associated with inflammatory signaling in NHDFs.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-016-1515-0) contains supplementary material, which is available to authorized users.

Cell adhesion proteins: roles in periodontal physiology and discovery by proteomics

Adhesion molecules expressed by periodontal connective tissue cells are involved in cell migration, matrix remodeling and inflammatory responses to infection. Currently, the processes by which the biologic activity of these molecules are appropriately regulated in time and space to preserve tissue homeostasis, and to control inflammatory responses and tissue regeneration, are not defined. As cell adhesions are heterogeneous, dynamic, contain a complex group of interacting molecules and are strongly influenced by the type of substrate to which they adhere, we focus on how cell adhesions in periodontal connective tissues contribute to information generation and processing that regulate periodontal structure and function. We also consider how proteomic methods can be applied to discover novel cell-adhesion proteins that could potentially contribute to the form and function of periodontal tissues.

Periadnexal mucin as an additional histopathologic feature of chronic eczematous dermatitis

Background

Cutaneous mucinoses are a heterogeneous group of disorders characterized by an abnormal amount of mucin in the skin. However, the pathomechanism of an excessive mucin deposition in the skin is still unknown. Eczematous dermatitis is sub-classified histologically into acute, subacute, and chronic variants. The characteristic histopathologic findings for chronic eczema are variable. However, periadnexal mucin deposition is not known as a feature of chronic eczema.

Objective

To evaluate the presence of periadnexal mucin deposition in chronic eczematous dermatitis.

Methods

We analyzed the skin biopsy specimens from 36 patients who were pathologically diagnosed with chronic eczematous dermatitis. Alcian blue, colloidal iron, and periodic acid-Schiff stains were used to evaluate the mucin deposition in histologic sections. Two dermatologists and two dermatopathologists evaluated the degree of mucin deposition using a 4-point scale.

Results

Various amounts of mucin deposition were observed in the periadnexal area of patients who were diagnosed with chronic eczema. Mucin deposition was more visible after staining with mucin-specific stains. Evaluation of the staining analysis scores revealed that the staining intensities were significantly higher in patients with chronic eczema than age- and site-matched controls (normal, acute to subacute eczema, and psoriasis vulgaris).

Conclusion

Periadnexal mucin (secondary mucinoses) may be an additional finding of chronic eczematous dermatitis.

Role of PTPα in the destruction of periodontal connective tissues

IL-1β contributes to connective tissue destruction in part by up-regulating stromelysin-1 (MMP-3), which in fibroblasts is a focal adhesion-dependent process. Protein tyrosine phosphatase-α (PTPα) is enriched in and regulates the formation of focal adhesions, but the role of PTPα in connective tissue destruction is not defined. We first examined destruction of periodontal connective tissues in adult PTPα^+/+ and PTPα^−/− mice subjected to ligature-induced periodontitis, which increases the levels of multiple cytokines, including IL-1β. Three weeks after ligation, maxillae were processed for morphometry, micro-computed tomography and histomorphometry. Compared with unligated controls, there was ∼1.5–3 times greater bone loss as well as 3-fold reduction of the thickness of the gingival lamina propria and 20-fold reduction of the amount of collagen fibers in WT than PTPα^−/− mice. Immunohistochemical staining of periodontal tissue showed elevated expression of MMP-3 at ligated sites. Second, to examine mechanisms by which PTPα may regulate matrix degradation, human MMP arrays were used to screen conditioned media from human gingival fibroblasts treated with vehicle, IL-1β or TNFα. Although MMP-3 was upregulated by both cytokines, only IL-1β stimulated ERK activation in human gingival fibroblasts plated on fibronectin. TIRF microscopy and immunoblotting analyses of cells depleted of PTPα activity with the use of various mutated constructs or with siRNA or PTPα^KO and matched wild type fibroblasts were plated on fibronectin to enable focal adhesion formation and stimulated with IL-1β. These data showed that the catalytic and adaptor functions of PTPα were required for IL-1β-induced focal adhesion formation, ERK activation and MMP-3 release. We conclude that inflammation-induced connective tissue degradation involving fibroblasts requires functionally active PTPα and in part is mediated by IL-1β signaling through focal adhesions.

Reticular erythematous mucinosis--a review

Reticular erythematous mucinosis (REM) is a rare cutaneous condition often referred to as plaque-like mucinosis and midline mucinosis. Although the exact etiology remains undefined, efforts to elucidate pathogenesis, disease associations, and prospective treatment modalities have been encouraging. Induction of the disease has been associated with viral processes, solar irradiation, specific cell lines, and cytokines such as Interleukin (IL)-1β. Clinically, patients typically develop erythematous macules and papules that coalesce into reticulated patterns on the midline of the chest or back. The lesions have a tendency to respond to systemic antimalarial therapy, but novel therapeutic approaches with ultraviolet A1 light (UVA1) and pulse dye laser (PDL) have been promising. Histologically, REM is associated with a mild, predominantly lymphocytic infiltrate with variable deep perivascular extension. Mucin may be seen in the upper and mid dermis and is prominent around the infiltrate and appendages. IgM deposits may be visualized under direct immunoflourescence along the basal layer. Because of the similarities between REM and tumid lupus, the two disease processes have often been grouped together. The remarkable overlap between the two diseases suggests that the two conditions may actually be the same disease.

UVB irradiation down-regulates type XVI collagen expression in mouse and human skin

BACKGROUND

Type XVI collagen is a member of the fibril-associated collagens with interrupted triple helices; however, its function or regulation remain unclear.

AIMS

This study is to examine the effect of ultraviolet B (UVB) or photoaging on type XVI collagen expression in various cultured cells, mouse, and human skin.

METHODS

The level of α1 (XVI) collagen mRNA was determined by quantitative real-time reverse transcriptase-polymerase chain reaction and the localization of type XVI collagen in normal human skins was detected by theα1 (XVI) collagen polypeptide antibody.

RESULTS

Exposure of keratinocytes resulted in suppression of mRNA level in a dose- and time-dependent manner and in normal fibroblasts or organotypic cocultures was also inhibited. Expression level in hairless mouse skin was decreased by UVB exposure. Messenger RNA level of human skins in the sun-protected area appeared to be greater than that in the sun-exposed area. Sun-protected and sun-exposed normal skin taken from young subjects showed positive immunoreactivities with the anti-α1 (XVI) collagen antibody in the subepidermal region, whereas sun-exposed skin from elderly subjects exhibited negative immunoreaction.

CONCLUSIONS

Reduction of type XVI collagen by UVB irradiation in vitro and in vivo may be related to the alteration of extracellular matrix in the photodamaged skin.

New insights into the mechanisms of innate immune receptor signalling in fibrosis

Recent advances in our understanding of innate immunity and inflammation have direct bearing on how we understand autoimmunity, and fibrosis, and how innate immune sensors might stimulate both of these key features of several fibrotic diseases. Toll-like receptors (TLRs) are the major receptors for recognizing pathogen associated molecular patterns present on bacterial cell walls, such as LPS, and nucleic acids (RNA and DNA). Several intracellular pathways mediate TLR effects and initiate various pro-inflammatory programs. Mechanisms for control of inflammation, matrix remodeling, and ultimately fibrosis are also activated. Transforming growth factor-beta (TGF-β), Interleukin-1 (IL-1), interleukin-4 (IL-4), interleukin-6 (IL-6), interleukin-13 (IL-13), and interferon (IFNs) appear particularly important in regulating pro-fibrotic aspects of innate immune activation. These mechanisms appear important in fibrotic disease affecting multiple organ-systems, including lung, liver, kidney, and skin. These observations provide new paradigms for understanding the relationship between immunity/inflammation and fibrosis, however, the precise ligand and mechanism linking innate immune sensor(s) to fibrosis remain uncertain in most illnesses.

Identification of specific chondroitin sulfate species in cutaneous autoimmune disease

Cutaneous lupus erythematosus and dermatomyositis (DM) are chronic inflammatory diseases of the skin with accumulated dermal mucin. Earlier work has shown chondroitin sulfate (CS) accumulation within the dermis of discoid lupus erythematosus (DLE), subacute cutaneous lupus erythematosus (SCLE), and DM lesions compared with control skin. Immunohistochemistry for C4S revealed a greater density in DLE and DM lesions, whereas SCLE lesions did not differ from controls. Scleredema and scleromyxedema are attributed to increased hyaluronic acid, and lesional samples from these diseases also demonstrated accumulated dermal C4S. Interferon-γ and interleukin-1α, but not interferon-α, treatment of cultured dermal fibroblasts induced mRNA expression of CHST-11, which attaches sulfates to the 4-position of unsulfated chondroitin. These studies on possible CS core proteins revealed that serglycin, known to have C6S side chains in endothelial cells, had greater density within DM dermal endothelia but not in DLE or SCLE, following the pattern of C6S overexpression reported previously. CD44 variants expand the CS binding repertoire of the glycoprotein; CD44v7 co-localized to the distribution of C4S in DLE lesions, a finding not observed in DM, SCLE lesions, or controls. Because C4S and C6S have immunologic effects, their dysregulation in cutaneous mucinoses may contribute to the pathogenesis of these disorders.

Th17 peripheral cells are increased in diffuse cutaneous systemic sclerosis compared with limited illness: a cross-sectional study

Systemic Sclerosis (SSc) is an autoimmune disease characterized by fibrosis and vasculopathy. A key feature is the presence of T cells in inflammatory lesions. To establish the differences in peripheral blood T helper (Th) subpopulations in diffuse cutaneous (dc) and limited cutaneous (lc) SSc patients, blood samples from 57 dcSSc and 78 lcSSc patients were obtained. Controls were collected from healthy volunteers (n = 16), active systemic lupus erythematosus (aSLE) patients (n = 13), and active rheumatoid arthritis (aRA) patients (n = 12). Mononuclear cells were analyzed by flow cytometry to determine Th1 (CD4+/IFN-γ+), Th2 (CD4+/IL-4+), Th17 (CD4+/IL-17+), and regulatory T cells (Tregs; CD4+/CD25+/Foxp3+) subsets. Th17 and Th1 subsets were increased in SSc groups versus healthy controls (P < 0.001) and aSLE patients (P < 0.001 for Th17 and P < 0.008 for Th1). Th2 cells were higher in dcSSc patients than in the healthy and aSLE groups (P = 0.03 and P = 0.009, respectively). Tregs were increased in the aRA group when compared with SSc patients and healthy controls (P ≤ 0.003). Patients with immunosuppressive treatment had lower numbers of Th17 and Th2 cells (P = 0.02). Our results shed further light into the preponderant role of Th17 and Th1 in patients with SSc. However, these findings certainly deserve to be studied in depth.

Expression of TNF-α and RANTES in drug-induced human gingival overgrowth

Objectives:

Regulated on activation, normal T cell expressed and secreted (RANTES) is a chemokine that is produced by fibroblasts, lymphoid and epithelial cells of the mucosa in response to various external stimuli. RANTES expression has been demonstrated in a variety of diseases characterized by inflammation, including asthma, transplantationassociated accelerated atherosclerosis, endometriosis and fibrosis. RANTES mRNA is quickly up-regulated by tumor necrosis factor (TNF)-α stimulation. Cyclosporine A (CsA) is widely used in organ transplant patients, often causing various side-effects including gingival overgrowth, which is fibrotic in nature. This study was carried out to assess the mRNA expression of TNF-α and RANTES in healthy individual, chronic periodontitis and CsAinduced gingival overgrowth tissues.

Materials and Methods:

Gingival tissue samples were collected from chronic periodontitis, CsAinduced gingival overgrowth patients and healthy individuals. Total RNA was isolated and reverse transcription polymerase chain reaction (RT-PCR) was performed for TNF-α and RANTES expression.

Results:

The results suggest that CsAinduced gingival overgrowth tissues expressed significantly increased TNF-α and RANTES compared to control and chronic periodontitis.

Conclusion:

The findings of the present study suggest that CsA can modify the expression of TNF-α and RANTES in drug-induced human gingival overgrowth.

Epithelial regulation of mesenchymal tissue behavior

Fibroproliferative scars are an important clinical problem, and yet the mechanisms that regulate scar formation remain poorly understood. This study explored the hypothesis that the epithelium has a critical role in dictating scar formation, and that these interactions differ in skin and mucosa. Paired skin and vaginal mucosal wounds on New Zealand white (NZW) rabbits diverged significantly; the cutaneous epithelium exhibited a greater and prolonged response to injury when compared with the mucosa. Microarray analysis of the injured epithelium was performed, and numerous factors were identified that were more strongly upregulated in skin, including several proinflammatory cytokines and profibrotic growth factors. Analysis of the underlying mesenchymal tissue demonstrated a fibrotic response in the dermis of the skin but not the mucosal lamina propria, in the absence of a connective tissue injury. To determine if the proinflammatory factors produced by the epidermis may have a role in dermal fibrosis, an IL-1 receptor antagonist was administered locally to healing skin wounds. In the NZW rabbit model, blockade of IL-1 signaling was effective in preventing hypertrophic scar formation. These results support the idea that soluble factors produced by the epithelium in response to injury may influence fibroblast behavior and regulate scar formation in vivo.

Induction of MMP-1, MMP-3 and TIMP-1 in normal dermal fibroblasts by chronic venous leg ulcer wound fluid*

In the wound bed of chronic venous leg ulcers, an imbalance of matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) may cause excessive proteolysis and impair wound granulation. Soluble mediators in the wound environment may be responsible for this imbalance. The in vitro effect of wound fluid from venous leg ulcers on dermal fibroblast production of MMP-1, MMP-3 and TIMP-1 was compared with the effect of acute wound fluid from two different sources: fluid from post-mastectomy axillary drains and fluid from skin graft donor sites. Significantly higher MMP-1 and MMP-3 levels were induced by chronic venous leg ulcer wound fluid compared with both types of acute wound fluid (P < 0.005). Chronic venous ulcer wound fluid reduced TIMP-1 protein levels significantly more than acute graft fluid (P < 0.05). Venous ulcer wound fluid significantly increased MMP-1 and MMP-3 production in dermal fibroblasts and reduced TIMP-1 production, confirming that mediators in the leg ulcer microenvironment can potentially induce excessive proteolysis in the ulcer dermis by altering the balance between MMPs and TIMPs. Inflammatory mediators including interleukin-1beta and tumour necrosis factor-alpha can induce these MMPs. Further work is required to confirm the factors responsible for the induction of a high MMP and low TIMP profile in fibroblasts by venous ulcer wound fluid.

The immunobiology of systemic sclerosis

OBJECTIVES

Systemic sclerosis (SSc) is a chronic connective tissue disease characterized by vascular damage, autoimmunity, and excessive collagen deposition. Despite advances in disease-specific treatment of other rheumatologic diseases, disease-targeted treatment in SSc continues to be elusive. In this review, our goal was to place the contemporary immunobiology of SSc in the perspective of clinical medicine.

METHODS

We performed a PubMed search for the period from 1989 to 2007, using the keyword, "systemic sclerosis," resulting in a total of 9099 publications, including 1252 reviews. Articles were then selected based on their discussion of recent advances in the elusive pathogenesis of SSc. A final total of 259 articles were chosen for the review.

RESULTS

The SSc hallmarks of vascular damage, immunologic activation, and collagen deposition can be traced to 4 major factors: T-cells, fibroblasts, B-cells, and cytokines/chemokines. T-cells are a major component of the infiltrate in skin and lung, exhibiting increased expression of activation markers and showing signs of antigen-driven expansion. Preliminary data indicate that induction of oral tolerance with collagen, a target of SSc T-cell responses, is associated with clinical benefits. Although this suggests that T-cells participate in the pathogenesis of SSc, their precise role and antigen specificity largely remain to be elucidated. Defective numbers and functions of certain T-cell subsets, such as natural killer and gammadelta T-cells, may be involved in the failure to maintain tolerance. Other data suggest that gammadelta T-cells may themselves be effector cells in endothelial cell cytotoxicity. There are several lines of evidence for a pathogenic role of B-cells in SSc, in particular, through the production of autoantibodies. Antibody-dependent cell-mediated cytotoxicity is a primary pathogenic event in an animal model of SSc and is likely to be involved in human SSc. Nonetheless, there is as yet no convincing evidence for the pathogenicity of SSc-specific antibodies. SSc fibroblasts exhibit a specific phenotype characterized not only by excessive collagen production but also by increased responsiveness to and production of cytokines and chemokines. This phenotype is induced by a complex network of cytokines and chemokines but appears to be maintained in the absence of exogenous stimuli via the autocrine production of some of these factors by SSc fibroblasts themselves, particularly transforming growth factor, platelet-derived growth factor, monocyte chemoattractant protein 1, and interleukin-1.

CONCLUSIONS

Significant variations in laboratory data among patients suggest that the pathology reflects a heterogeneous disease. Nonetheless, the possibility of achieving clinical benefits by inducing oral tolerance highlights the importance of characterizing SSc T-cell antigens. It is hoped that the identification of some of the key players in the induction and maintenance of the SSc fibroblast phenotype may yield new disease-targeted treatment regimens for patients with SSc.

Autocrine TGF-beta signaling in the pathogenesis of systemic sclerosis

Excessive extracellular matrix deposition in the skin, lung, and other organs is a hallmark of systemic sclerosis (SSc). Fibroblasts isolated from sclerotic lesions in patients with SSc and cultured in vitro are characterized by increased synthesis of collagen and other extracellular matrix components, consistent with the disease phenotype. Thus, cultured scleroderma fibroblasts serve as a principal experimental model for studying the mechanisms involved in extracellular matrix overproduction in SSc. The pathogenesis of SSc is still poorly understood, but increasing evidence suggests that transforming growth factor-beta (TGF-beta) is a key mediator of tissue fibrosis as a consequence of extracellular matrix accumulation in the pathology of SSc. TGF-beta regulates diverse biological activities including cell growth, cell death or apoptosis, cell differentiation, and extracellular matrix synthesis. TGF-beta is known to induce the expression of extracellular matrix proteins in mesenchymal cells and to stimulate the production of protease inhibitors that prevent enzymatic breakdown of the extracellular matrix. This review focuses on the possible role of autocrine TGF-beta signaling in the pathogenesis of SSc.

Hydrated keratinocytes reduce collagen synthesis by fibroblasts via paracrine mechanisms

Regulating collagen metabolism can control hypertrophic scars in cutaneous wounds. Hypertrophic scars can be reduced by occlusive dressings such as silicone sheeting; however, their mechanism is still unknown. We hypothesized that hydration of keratinocytes reduces the collagen secretion of fibroblasts by modifying the cytokine levels. Stratified human epidermal keratinocytes and confluent human dermal fibroblasts were co-cultured serum free for 72 hours. Keratinocytes were either kept at the air interface or hydrated. Messenger RNA (mRNA) levels of interleukin-1 (IL-1)alpha, IL-1beta, tumor necrosis factor alpha (TNF-alpha), keratinocyte growth factor (KGF), and procollagen-1 were analyzed by real-time reverse transcription-polymerase chain reaction. Secretion of cytokines into conditioned media was quantified by enzyme-linked immunosorbent assay and collagen content by Western blot. The content of collagen-I decreased by 44% in the presence of hydrated keratinocytes. Co-culture with air-treated keratinocytes decreased collagen-I only by 23%. Co-cultured hydrated keratinocytes had significantly higher TNF-alpha mRNA (172%) than hydrated keratinocytes. At the protein level, there was an overall trend toward increased TNF-alpha levels in hydrated cultures. IL-1beta secretion decreased significantly under hydration (42% monoculture, 58% co-culture). Co-culture stimulated a 240% increase of KGF mRNA in fibroblasts compared with monocultured fibroblasts. Fibroblasts secreted 4.5-fold more KGF in hydrated co-cultures and sixfold more KGF in air-treated co-cultures. Hydration of keratinocytes modifies important paracrine interactions between keratinocytes and fibroblasts and reduces collagen-1, which supports the hypothesis that hydration of the epidermis and restoration of water barrier function play an important role in scar formation.

Perforating folliculitis associated with tumour necrosis factor-? inhibitors administered for rheumatoid arthritis

Perforating dermatoses are characterized by transepithelial elimination of dermal structures. We report a 61-year-old man with rheumatoid arthritis who developed a perforating folliculitis following the administration of two tumour necrosis factor (TNF)-alpha inhibitors, infliximab and etanercept. To our knowledge, no perforating disorders have been reported associated with these drugs. This report suggests, for the first time, a role for TNF-alpha in the pathogenesis of perforating folliculitis.

Oxidative and Heat Stress Gene Changes in Hypertrophic Scar Fibroblasts Stimulated with Interleukin-1β1

INTRODUCTION

Cutaneous wounds that involve loss of tissue heal through a complex process of generating granulation tissue to initially cover the wound, followed by epithelialization, and contraction. Normal healing requires a delicate balance between cellular, matrix, and vascularity build up and breakdown. Defects in the regulation of this balance can alter normal scar formation through fibroblastic hyperproliferation, which is characteristic of hypertrophic scar formation.

METHODS

Primary fibroblasts cultures from hypertrophic scar or adjacent normal skin were seeded in growth medium. Half of each was stimulated with interleukin (IL)-1beta for 6 h and half served as control nonstimulated fibroblasts. Supernatants were tested for expressed proteins and the fibroblasts for changes in gene expression.

RESULTS

Comparison between normal skin and hypertrophic scar fibroblasts stimulated with IL-1beta indicate that 15 genes increased and 8 genes decreased expression. When normal skin was stimulated with IL-1beta, there were increases in the expression of heat shock transcription factor-1, hsp70, and IL-6 When hypertrophic scar was stimulated with IL-1beta, there was a decrease in nuclear factor-kappaB, GADD45-alpha, p53, p53 binding protein, and Cox-2 genes. These genes may play specific but different roles in controlling the cellular response to cell stress and apoptosis.

CONCLUSION

Data presented suggest that oxidative and heat stress proteins, stimulated through IL-1beta, may be important mediators of abnormal scarring.

The role of the Th2 CC chemokine ligand CCL17 in pulmonary fibrosis

Increasing evidence suggests that the development of pulmonary fibrosis is a Th2-mediated process. We hypothesized that the CC chemokines that are associated with a Th2 profile (CCL17 and CCL22) have an important role in the development of pulmonary fibrosis. We measured CCL17 and CCL22 during the pathogenesis of bleomycin-induced pulmonary fibrosis. We found that both CCL17 and CCL22 were significantly elevated through day 20 as compared with control mice. Peak expression of CCL22 preceded the peak levels of CCL17, as measured by real-time quantitative PCR. CCR4 is the receptor for CCL17 and CCL22 therefore, to further characterize the role of CCL17 and CCL22, we measured CCR4 mRNA in lung tissue of bleomycin-treated mice by real-time quantitative PCR. CCR4 was significantly elevated in bleomycin-treated mice as compared with control mice. Immunolocalization demonstrated that CCR4 was expressed predominantly on macrophages. Neutralization of CCL17, but not CCL22, led to a reduction in pulmonary fibrosis. Immunolocalization of bleomycin-treated lung tissue and human idiopathic pulmonary fibrosis tissue specimens showed that epithelial cells expressed CCL17. These findings demonstrate a central role for Th2 chemokines and the macrophage in the pathogenesis of pulmonary fibrosis and are further support for the role of a Th2 phenotype in the pathogenesis of pulmonary fibrosis.

APC0576 decreases production of pro-inflammatory chemokine and extracellular matrix by human Tenon's capsule fibroblasts

PURPOSE

To control intraocular pressure in patients treated by trabeculectomy, progressive inflammation, fibroblast proliferation, and the enhanced expression of extracellular matrix (ECM), causes of scar formation at the bleb, must be prevented. Using human Tenon's capsule fibroblasts (TCFs), we examined the effect of APC0576, a suppressor of NF-kappaB-dependent gene activation of human vascular endothelial cells that does not adversely affect cell viability, on the production of pro-inflammatory chemokine and ECM. Its effect on TCF proliferation was also assessed.

METHODS

Enzyme-linked immunosorbent assay was used to detect the pro-inflammatory cytokines IL-8 and MCP-1 in the supernatant of TCFs stimulated with IL-1alpha in the presence or absence of APCO576 and ECM proteins, COOH-terminal peptide of type I procollagen (PIP), fibronectin (FN), and laminin (LN) in supernatants and lysates of TCFs stimulated with IL-1alpha or TGF-beta. The proliferative response of IL-1alpha-stimulated TCFs was examined using the SF formazan solution reaction.

RESULTS

APC0576 significantly suppressed the production by TCFs of IL-8 (p<0.0001), MCP-1(p<0.0001), PIP (supernatants: p<0.0001, cell lysates: p<0.0001), LN (supernatants: p<0.0001, lysates: p<0.0001), and FN (supernatants: p<0.0001, lysates: p<0.0001) as well as their proliferation (p<0.0001).

CONCLUSIONS

APC0576 suppressed pro-inflammatory chemokine and ECM production in TCFs as well as their proliferation. It may represent a novel candidate for the postoperative management of patients treated by trabeculectomy.

Combinatorial signaling pathways determine fibroblast proliferation and myofibroblast differentiation

Fibroblast proliferation, differentiation into myofibroblasts, and increased collagen synthesis are key events during both normal wound repair and fibrotic lesion formation. Here we report that these biological responses to TGF-beta by fibroblasts are regulated via a CTGF-dependent pathway in concert with either EGF or IGF-2. Our studies indicate these responses to TGF-beta are mutually exclusive, and cells that are proliferating do not express alpha-SMA or elevated levels of collagen synthesis. Cells expressing alpha-SMA do not exhibit DNA synthesis but do coexpress higher levels of types I and III collagen mRNA. Thus, fibroblast proliferation and differentiation are controlled by combinatorial signaling pathways involving not only components of the TGF-beta/CTGF pathway, but also signaling events induced by EGF and IGF-2-activated receptors. Collectively, our studies indicate TGF-beta functions as a classic embryonic inducer, initiating a cascade that is controlled by other factors in the cellular environment. We propose a model for this process with regard to wound repair and fibrotic lesion formation that is likely applicable to other instances of CTGF action during embryogenesis.

Self-healing papular mucinosis in an adult

Papular mucinosis is a rare, idiopathic cutaneous mucinosis that is typically chronic and progressively severe. We present a case of a 59-year-old woman with a 6-month history of a dramatic papular eruption on her face and neck, with no associated internal organ involvement. A biopsy specimen demonstrated increased dermal mucin with associated plump fibroblasts, consistent with a diagnosis of papular mucinosis. Multiple therapeutic interventions were unsuccessful, and after 2 years the lesions resolved spontaneously without treatment. During the following 3 years, the patient has had no recurrence of disease.

Dose-dependent impairment of collagen deposition by topical granulocyte-macrophage colony-stimulating factor in human experimental wounds

OBJECTIVE

The authors studied the dose-dependent effect of topically administered granulocyte-macrophage colony-stimulating factor (GM-CSF) on the connective tissue response using an experimental repair model in surgical patients.

SUMMARY BACKGROUND DATA

GM-CSF is primarily indicated in the treatment of immunosuppressed states. The effect of GM-CSF on the tissue repair response in humans is unclear.

METHODS

Expanded polytetrafluoroethylene tubes were implanted subcutaneously and GM-CSF was applied locally at concentrations of 0.1 micro g/mL (total dose 0.4 micro g), 1.0 micro g/mL (4.0 micro g), 10 micro g/mL (40 micro g), or 75 micro g/mL (300 micro g) in one arm and saline alone (control) in the contralateral arm of 56 surgical patients. The content of collagen and total protein in the tubes was quantified as hydroxyproline and proline by high-performance liquid chromatography 10 days after implantation. Cellularity and the number of procollagen I-positive fibroblasts were determined by histology and immunohistochemistry. The direct effects of GM-CSF on collagen production by and proliferation of wound fibroblasts cultured from granulation tissue were also measured.

RESULTS

Local application of GM-CSF stimulated the inflammatory cell infiltration but reduced the number of fibroblasts in the granulation tissue. GM-CSF treatment suppressed specifically and dose-dependently collagen deposition by up to 81%. A reduced collagen accumulation was also found in the control-treated arm at GM-CSF doses of 4 micro g or more, indicating a systemic depressive effect of GM-CSF on tissue repair. The selective downregulation of collagen production by GM-CSF was also found in wound fibroblasts in vitro.

CONCLUSIONS

Inhibition of fibrogenesis with GM-CSF intervention may impair tissue repair processes during surgery.

Dose-dependent impairment of collagen deposition by topical granulocyte-macrophage colony-stimulating factor in human experimental wounds

OBJECTIVE

The authors studied the dose-dependent effect of topically administered granulocyte-macrophage colony-stimulating factor (GM-CSF) on the connective tissue response using an experimental repair model in surgical patients.

SUMMARY BACKGROUND DATA

GM-CSF is primarily indicated in the treatment of immunosuppressed states. The effect of GM-CSF on the tissue repair response in humans is unclear.

METHODS

Expanded polytetrafluoroethylene tubes were implanted subcutaneously and GM-CSF was applied locally at concentrations of 0.1 micro g/mL (total dose 0.4 micro g), 1.0 micro g/mL (4.0 micro g), 10 micro g/mL (40 micro g), or 75 micro g/mL (300 micro g) in one arm and saline alone (control) in the contralateral arm of 56 surgical patients. The content of collagen and total protein in the tubes was quantified as hydroxyproline and proline by high-performance liquid chromatography 10 days after implantation. Cellularity and the number of procollagen I-positive fibroblasts were determined by histology and immunohistochemistry. The direct effects of GM-CSF on collagen production by and proliferation of wound fibroblasts cultured from granulation tissue were also measured.

RESULTS

Local application of GM-CSF stimulated the inflammatory cell infiltration but reduced the number of fibroblasts in the granulation tissue. GM-CSF treatment suppressed specifically and dose-dependently collagen deposition by up to 81%. A reduced collagen accumulation was also found in the control-treated arm at GM-CSF doses of 4 micro g or more, indicating a systemic depressive effect of GM-CSF on tissue repair. The selective downregulation of collagen production by GM-CSF was also found in wound fibroblasts in vitro.

CONCLUSIONS

Inhibition of fibrogenesis with GM-CSF intervention may impair tissue repair processes during surgery.

Pathogenesis of fibrosis: role of TGF-beta and CTGF

Transforming growth factor (TGF)-beta regulates diverse biologic activities including cell growth, cell death or apoptosis, cell differentiation, and extracellular matrix (ECM) synthesis. TGF-beta is believed to be a key mediator of tissue fibrosis as a consequence of ECM accumulation in pathologic states such as systemic sclerosis. TGF-beta is known to induce the expression of ECM proteins in mesenchymal cells, and to stimulate the production of protease inhibitors that prevent enzymatic breakdown of the ECM. Connective tissue growth factor (CTGF), which is induced by TGF-beta, has been reported to mediate stimulatory actions of TGF-beta ECM synthesis. This review focuses on the possible role of TGF-beta and CTGF in the pathogenesis of fibrosis.

IL-4 up-regulates the expression of tissue inhibitor of metalloproteinase-2 in dermal fibroblasts via the p38 mitogen-activated protein kinase dependent pathway

Tissue inhibitor of metalloproteinase-2 (TIMP-2) is a potent inhibitor of activated matrix metalloproteinases such as gelatinase and collagenase, and thus helps to control extracellular matrix metabolism and deposition by connective tissue cells. We examined the responsiveness of the expression of TIMP-2 to various cytokines in dermal fibroblasts and studied the regulatory and signaling mechanisms of the response. TIMP-2 protein and mRNA expression was induced by IL-4 in a dose- and time-dependent manner, but not by TGF-beta, oncostatin M, or IL-6. IL-4 induction of TIMP-2 expression was dependent upon transcription. The p38 mitogen-activated protein kinase (MAPK) inhibitors SB202190 and SB203580 suppressed IL-4-induced TIMP-2 expression, suggesting the involvement of p38 MAP kinase in the signaling of IL-4 leading to TIMP-2 expression. Immunoblotting analysis using a specific Ab against phosphorylated p38 MAP kinase (Thr(180)/Tyr(182)) showed that IL-4 induced phosphorylation of p38 MAP kinase in human dermal fibroblasts. Furthermore, the p38 MAP kinase assay showed that IL-4 induces p38 MAPK activation in human dermal fibroblasts. The expression of the dominant-negative mutant p38 MAPK represses the IL-4-induced TIMP-2 expression in human dermal fibroblasts. Thus, IL-4 can potentially alter the dermal matrix metabolism by regulating TIMP-2.

The importance of balanced pro-inflammatory and anti-inflammatory mechanisms in diffuse lung disease

The lung responds to a variety of insults in a remarkably consistent fashion but with inconsistent outcomes that vary from complete resolution and return to normal to the destruction of normal architecture and progressive fibrosis. Increasing evidence indicates that diffuse lung disease results from an imbalance between the pro-inflammatory and anti-inflammatory mechanisms, with a persistent imbalance that favors pro-inflammatory mediators dictating the development of chronic diffuse lung disease. This review focuses on the mediators that influence this imbalance.

Understanding the final stages of wound contraction

Much research has been undertaken to improve our understanding of the processes of wound contraction. This article, the second in a two-part series, focuses on granulation tissue modulation.

Cutaneous mucinoses: microscopic criteria for diagnosis

The clinical aspects and the histologic features of cutaneous mucinoses have been reviewed and their classification updated. Cutaneous mucinoses are divided into distinctive (primary) cutaneous mucinoses in which the mucin deposit is the main histologic feature resulting in clinically distinctive lesions, and disorders associated with histologic mucin deposition as an additional finding (secondary mucinoses). The former are further divided into degenerative-inflammatory mucinoses, which may be either dermal or follicular, and into neoplastic-hamartomatous mucinoses. Histopathologic diagnosis is particularly difficult for dermal mucinoses and requires clinicopathologic correlation. Three histologic clues, namely the pattern of mucin distribution (diffuse or focal), the level of mucin deposit in the dermis and some additional findings may help diagnosis. Follicular mucinoses have the easiest pattern to recognize histologically, but the distinction between Pinkus' follicular mucinosis and follicular mucinosis with mycosis fungoides is very difficult.Lastly, neoplastic-hamartomatous cutaneous mucinoses include mucinous nevus, a benign hamartoma, and myxoma, which is a benign tumor to be differentiated from reactive cutaneous focal mucinosis.

Novel therapy in the treatment of scleroderma

While the biology of the pathogenesis of scleroderma is continually being better understood, there still is no single agent or therapeutic combination that has a clear impact on the disease process. Traditional medications (colchicine, potassium aminobenzoate (potaba), D-penicillamine) are disappointing in clinical practice despite anecdotal evidence of benefit. Furthermore, the most popular traditional drug, D-penicillamine, failed to clearly show benefit when tested in a well-designed clinical trial comparing conventional high dose with a very low dose (125 mg po. every other day [corrected]) [1]. Currently, most success in managing scleroderma and improving quality of life is secondary to organ-specific therapy, such as management of a renal crisis with an ACE inhibitor, treatment of Raynaud's phenomenon with calcium channel blockers, or control of serious gastrointestinal reflux disease with a proton pump inhibitor. In this review we will focus on novel therapies that are currently being tested in the treatment of scleroderma and have the potential of modifying the disease process and overall clinical outcome. We have attempted to review the rationale for each agent, recognising that its true biological effect will only be determined in clinical trials.

Oncostatin M stimulates the growth of dermal fibroblasts via a mitogen-activated protein kinase-dependent pathway

Oncostatin M (OSM), a member of the hemopoietic cytokine family, has been implicated in the process of fibrosis and dermal wound healing. As a part of an ongoing study of the mechanisms of fibrosis and dermal wound healing, we have investigated the mechanism of the growth regulation of dermal fibroblasts by OSM. OSM stimulates the mitogenesis of dermal fibroblasts in a dose-dependent manner. This effect was completely blocked by anti-OSM IgG, but not by anti-IL-6 IgG. Furthermore, OSM induction was abolished by genistein, a tyrosine kinase inhibitor, or by PD98059, a specific mitogen-activated protein (MAP) kinase pathway inhibitor, but not by calphostin C, a protein kinase C inhibitor. Immunoblotting analysis using a specific Ab against phosphorylated MAP kinase (Thr202/Tyr204) showed that OSM induces phosphorylation of MAP kinase in dermal fibroblasts. Furthermore, transient transfection of the dominant-negative mutant MAP kinase into dermal fibroblasts abolished the OSM induction. These results strongly suggest that OSM stimulates the growth of dermal fibroblasts via a MAP kinase-dependent pathway.

The role of the immune system in conjunctival wound healing after glaucoma surgery

The immune system has a fundamental role in the development and regulation of ocular healing, which plays an important role in the pathogenesis of most blinding diseases. This review discusses the mechanisms of normal wound healing, describing the animal and fetal wound healing models used to provide further insight into normal wound repair. In particular, conjunctival wound repair after glaucoma filtration surgery will be used to illustrate the contributions that the different components of the immune system make to the healing process. The potential role of macrophages, the possible regulatory effect of lymphocytes, and the important role of growth factors and cytokines in the wound healing reaction are discussed. The significance of the immune system in the pathogenesis of aggressive conjunctival scarring is addressed, particularly assessing the predisposing factors, including drugs, age, and ethnicity. The rationale behind the pharmacological agents currently used to modulate the wound healing response and the effects these drugs have on the function of the immune system are described. Finally, potential new therapeutic approaches to regulating the wound healing response are reported.

Different expression of TNF-alpha receptors and prostaglandin E(2 )Production in normal and fibrotic lung fibroblasts: potential implications for the evolution of the inflammatory process

Normal human lung fibroblasts downregulate the production of tumor necrosis factor (TNF)-alpha by activated monocytes through the production of prostaglandin E(2) (PGE(2)), contributing to the local control of the inflammatory process. In this study, we provide evidence that fibroblasts derived from diseased tissue, such as fibrotic lung fibroblasts, exhibit different functional features compared with normal cells, with particular regard to their modulatory role. Indeed, fibrotic fibroblasts (FF) spontaneously produced less PGE(2) (3,300 +/- 410 pg/ml) compared with normal fibroblasts (NF) (7,500 +/- 270 pg/ml) and, as a consequence, they showed a reduced ability to downregulate the production of TNF-alpha by lipopolysaccharide (LPS)- activated monocytes. The percentage of inhibition induced by normal cells on the production of TNF-alpha by LPS-activated monocytes was 61 +/- 5.9%, whereas the inhibitory effect exerted by fibrotic cells was reduced to 32 +/- 4% (P < 0.01). We have also observed that the ability of TNF-alpha to induce PGE(2) was impaired in FF and was related to a reduced expression of cyclooxygenase 2. This was possibly due to the reduction of the expression of TNF receptors (TNFRs) in fibrotic cell lines compared with normal cell lines. Flow cytometry revealed that the mean fluorescence intensity (MFI) of both isoforms of TNFR was significantly lower in FF compared with NF. The MFI of TNFR1 was 3. 55 +/- 0.12 for NF and 1.78 +/- 0.35 for FF (P < 0.001). The MFI of TNFR2 was 1.95 +/- 0.27 for NF and 0.99 +/- 0.16 for FF (P < 0.01). The analysis of the effect of TNF-alpha on some functions associated with collagen metabolism in NF and FF showed an increase of the expression of the receptor for collagen type I (alpha(2)beta(1) integrin) in NF (42 +/- 10%) and an even larger increase in FF (102 +/- 23%) (P < 0.05). Interestingly, unlike NF, TNF-alpha failed to increase matrix metalloproteinase 1 levels in FF and did not cause any growth inhibition in these cells. The reduced capability of fibrotic cells to produce PGE(2) either spontaneously or after TNF-alpha treatment may lead to an unrestrained release of TNF-alpha from activated monocytes and, as a result of the reduced expression of TNFRs, to a different response of these cells to TNF-alpha. These changes may be important in the evolution of the inflammatory process, potentially contributing to its transformation into a chronic and self-perpetuating process.

Differential regulation of metalloproteinase production, proliferation and chemotaxis of human lung fibroblasts by PDGF, interleukin-1beta and TNF-alpha

Fibroblast migration, proliferation, extracellular matrix protein synthesis and degradation, all of which play important roles in inflammation, are themselves induced by various growth factors and cytokines. Less is known about the interaction of these substances on lung fibroblast function in pulmonary fibrosis. The goal of this study was to investigate the effects of PDGF alone and in combination with IL-1beta and TNF-alpha on the production of human lung fibroblast matrix metalloproteinases, proliferation, and the chemotactic response. The assay for MMPs activity against FITC labeled type I and IV collagen was based on the specificity of the enzyme cleavage of collagen. Caseinolytis and gelatinolytic activities of secreted proteinases were analyzed by zymography. Fibronectin in conditioned media was measured using human lung fibronectin enzyme immunoassay. Cell proliferation was measured by 3H-Thymidine incorporation assay. Cell culture supernatants were tested for PGE2 content by ELISA. Chemotactic activity was measured using the modified Boyden chamber. Matrix metalloproteinase assay indicated that IL-1beta, TNF-alpha and PDGF induced intestitial collagenase (MMP-1) production. MMP assay also indicated that IL-1beta and TNF-alpha had inhibitory effects on MMP-2,9(gelatinaseA,B) production. Casein zymography confirmed that IL-1beta stimulated stromlysin (matrix metalloproteinase 3; MMP-3) and gelatin zymography demonstrated that TNF-alpha induced MMP-9 production in human lung fibroblast, whereas PDGF alone did not. PDGF in combination with IL-1beta and TNF-alpha induced MMP-3 and MMP-9 activity, as demonstrated by zymography. PDGF stimulated lung fibroblast proliferation in a concentration-dependent manner, whereas IL-1beta and TNF-alpha alone had no effect. In contrast, the proliferation of human lung fibroblasts by PDGF was inhibited in the presence of IL-1beta and TNF-alpha, and this inhibition was not a consequence of any elevation of PGE2. PDGF stimulated fibroblast chemotaxis in a concentration-dependent manner, and this stimulation was augmented by combining PDGF with IL-1beta and TNF-alpha. These findings suggested that PDGF differentially regulated MMPs production in combination with cytokines, and further that MMP assay and zymography had differential sensitivity for detecting MMPs. The presence of cytokines with PDGF appears to modulate the proliferation and chemotaxis of human lung fibroblasts.

Transient exposure to tumor necrosis factor-alpha inhibits collagen accumulation by cultured hypertrophic scar fibroblasts

BACKGROUND

Hypertrophic scars (HS) are frequent consequences of deep dermal injury, such as deep partial-thickness burns and abrasions, and are characterized by overproduction of collagen. In vitro studies have shown that cultured HS fibroblasts produce elevated levels of collagen and insulin-like growth factor-binding protein 3 (IGFBP-3). Additionally, histological studies have indicated HS contain fewer tumor necrosis factor alpha (TNF-alpha)-positive infiltrating cells and express lower levels of TNF-alpha mRNA, suggesting TNF-alpha, which can inhibit collagen expression in some systems, may function to deactivate the wound healing process in scars. HS also exhibit increased levels of transforming growth factor beta (TGF-beta), a factor that stimulates collagen and extracellular matrix deposition by fibroblasts and also stimulates IGFBP-3 expression. In some systems, IGFBP-3 mediates the effects of TGF-beta. The present study sought to determine the effects of continuous and transient TNF-alpha exposure on collagen and IGFBP-3 expression by cultured HS fibroblasts and to investigate the role of IGFBP-3 in collagen accretion by HS fibroblasts.

MATERIALS AND METHODS

Superficial and deep dermal HS fibroblasts from four patients were cultured. Fibroblasts were cultured in serum-free medium and exposed to 0-2 ng/ml TNF-alpha for 0, 1, 4, or 72 h. After 72 h of culture, medium samples were processed for Western blot analysis of type I collagen accumulation or for ligand blot analysis of IGFBP-3 accumulation. The effects of an anti-IGFBP-3 neutralizing antibody on collagen accumulation were also assessed.

RESULTS

Treatment of superficial and deep HS fibroblasts with TNF-alpha resulted in dose-dependent decreases in accumulation of both type I collagen and IGFBP-3 in the culture medium (P < 0.01). However, using the anti-IGFBP-3 neutralizing antibody, a causal relationship between decreased IGFBP-3 and decreased collagen accumulation could not be demonstrated. Transient exposure of cultured HS fibroblasts to TNF-alpha for as little as 1 h was as effective as continuous exposure to TNF-alpha for 72 h in inhibiting collagen accumulation.

CONCLUSIONS

These results support the hypothesis that TNF-alpha functions as a wound healing deactivation signal that is deficient in HS. Although TNF-alpha inhibited accretion of both collagen and IGFBP-3, the role of IGFBP-3 in HS remains unresolved. This study suggests that transient TNF-alpha exposure may be used to inhibit collagen overaccumulation in HS and that the timing of TNF-alpha exposure following dermal injury may not be critical for this inhibition.

Effect of hyperbaric oxygen on human skin cells in culture and in human dermal and skin equivalents

A critical stage of cutaneous wound healing is the development and maturation of the epidermis. In the aged, and in certain pathologies, this repair process is compromised due to a variety of deficiencies, one of which is tissue oxygenation. Several phases of wound healing are dependent on adequate tissue oxygen levels, and hyperbaric oxygenation has been shown to transiently elevate these levels. The use of human cell monolayers, dermal equivalents and human skin equivalents provide excellent opportunities for studying wound healing using in vivo relevant models. The goal of this study was to examine the effect of hyperbaric oxygen on cell proliferation, differentiation, and matrix biosynthesis in monolayer cultures and epidermopoiesis in the developing skin equivalent. Normal human dermal fibroblasts, keratinocytes and melanocytes, dermal equivalents and skin equivalents were exposed to hyperbaric oxygen at pressures up to three atmospheres, for up to 10 consecutive daily treatments lasting 90 minutes each. Increase in fibroblast proliferation (cf., 30% at 1 atmosphere after 10 days treatment), was observed without a significant effect on proliferation of normal human melanocytes and glycosaminoglycan synthesis. Stimulation of collagen synthesis after two days of treatment was only significant at 1 atmosphere (about 20% increase) but this differential was not observed after 5 days of treatment. Hyperbaric oxygenation above 2 atmospheres, inhibited proliferation of fibroblasts and keratinocytes in cell monolayer cultures (e.g., a 10 day treatment at 3 atmospheres appeared cytostatic to keratinocytes). In contrast, hyperbaric treatment up to 3 atmospheres dramatically enhanced keratinocyte differentiation, and epidermopoiesis in the complete human skin equivalent. These results support the importance of hyperbaric oxygen therapy in wound healing, and should provide an insight into oxygen utilization during repair of peripheral human tissue. The results also show the utility of the human skin equivalent as a model for evaluation of parameters involved in wound healing.

Structural and functional changes in the airway smooth muscle of asthmatic subjects

It has been recognized since the early 1920s that the amount of smooth muscle in asthmatic subjects' airways is markedly increased. More recent studies have confirmed that in fatal asthma there is a significant increase in the thickness of airway smooth muscle. For subjects who have had asthma and who died for other reasons or had a lobectomy, the increase in muscle layer thickness is less striking. An increase in smooth muscle mass could have a dual effect on airway narrowing: one due to the thickening of airway wall, the other due to a concomitant increase in force generation. However, it is not known whether the increased muscle mass, due either to hypertrophy or hyperplasia, is accompanied by an increase in force. Proliferation of smooth muscle cells often produces noncontractile cells in vitro. Comparison of force generation by muscle preparations from asthmatic and control airways shows conflicting results, with some studies demonstrating an increase in force in asthmatic muscle preparations and others showing no increase. The discrepancy could be due to a failure to take into account the length-tension relationship of the muscle preparations in some studies. No force velocity data are available for human airway smooth muscle. However, there is some evidence for an increased amount of shortening in airway smooth muscle preparations from patients with asthma. This could be due to an increase in force generation and/or a decrease in tissue elastance in asthmatic airways. Muscle contractility and tissue elastance are in turn influenced by cytokines, matrix-degrading enzymes, and other inflammatory mediators present in the airways of asthmatic subjects. Data from in vitro studies of a canine "asthma model" indicate an increase in both shortening velocity and amount of shortening compared with littermate control animals. An increase in the compliance of the parallel elastic element of the sensitized airway preparation could account for the mechanical alterations.

Procollagens and inflammatory cytokine concentrations in tarsal and limbal vernal keratoconjunctivitis

To quantify the presence of inflammatory/fibrogenic cytokines and procollagens type I (PICP) and III (PIIIP) in active and non-active tarsal and limbal forms of vernal keratoconjunctivitis (VKC), tear and blood samples were collected from 27 VKC patients (20 active and 7 non-active) and 15 normal subjects. Upper tarsal conjunctival biopses were obtained from 8 controls and 8 tarsal VKC patients. From biopses of 4 tarsal VKC, fibroblasts were cultured in F12 medium with 10% FCS. TGF-beta 1, IL-1 alpha, IL-1 beta, IL-6 and TNF-alpha, PICP and PIIIP were measured in: (1) tears, (2) homogenized conjunctival tissues, (3) serum, (4) supernatants of tissue cultures at 24 hr, and fibroblast primary passage cultures. Results showed: (1) in tears, TGF-beta 1 and TNF were identified in several active VKC patients without significant differences between the tarsal and the limbal forms. IL-1 beta (27 +/- 51 pg ml-1, P = 0.03) and IL-6 (28 +/- 43 pg ml-1, P = 0.006) were significantly increased in tarsal VKC compared to controls. Both control and non-active VKC tear samples had undetectable levels of all of the above cytokines. PICP and PIIIP were significantly increased in tarsal VKC compared to both limbal VKC and controls. Non-active VKC levels were similar to controls. (2) In homogenized VKC tissues, TGF-beta 1 and IL-6 were both significantly increased compared to controls (P < 0.01) while no increases were observed in IL-1 and TNF-alpha. (3) In serum, IL-1 alpha, IL-1 beta and TNF-alpha were higher in VKC patients compared to controls. (4) In vitro fibroblasts from VKC patients showed an increased production of TGF-beta 1, IL-1 alpha, IL-1 beta, IL-6, TNF-alpha, PICP, and PIIIP over time. Increased levels of TGF-beta 1, IL-1 and IL-6 in VKC tissues and tears indicate a local production of these cytokines in active VKC. Collagen hyperproduction occurs only in active tarsal VKC and may be related to high levels of TGF-beta 1, IL-1 and IL-6. Increased serum levels of IL-1 and TNF-alpha suggests that systemic immunological changes occur in VKC. Cell culture can be used as a model to further study the pathogenesis of VKC and its characteristic local fibroblast activation.

Type I and type III collagens in cutaneous mucinosis

Cutaneous mucinoses are a heterogeneous group of diseases characterized by the focal or diffuse dermal deposition of glycosaminoglycans. The histopathologic examination of many cutaneous mucinoses reveals that the collagen fibers are fragmented. We wanted to characterize the type I (COL1) and type III (COL3) collagen distribution in skin biopsy specimens of patients with cutaneous mucinosis. The diagnosis of mucinosis was based on a modification of the classification by Rongioletti and Rebora: four patients had familial papulonodular mucinosis: four had papular mucinosis, one of which was associated with myxedema and one had scleromyxedema; and one had focal mucinosis. We performed anti-type I and type III collagens immunolabeling on frozen sections. Immunofluorescence for COL1 was increased in the superficial dermis of 2/4 familial papulonodular mucinosis, in 5/5 of papular mucinosis, and in scleromyxedema and focal mucinosis cases. The mid-dermis showed intense staining for COL1 at the periphery of collagen bundles and, in three cases of familial papulonodular mucinosis and two cases of papular mucinosis, a lacy appearance. The superficial dermis of familial papulonodular mucinosis specimens and of papular mucinosis + myxedema, scleromyxedema, and focal mucinosis specimens had decreased COL3 staining. The mid-dermis showed a more prominent fibrillar staining at the periphery of the collagen bundles, and two cases of papular mucinosis showed intense labeling for COL3. Both COL1 and COL3 distributions are altered in cutaneous mucinosis. An intense labeling with COL1 is predominantly found in the superficial layer of cutaneous mucinosis. Cases of FTP revealed decreased COL3 reactivity at the superficial layer.

Regulations of collagen synthesis by ascorbic acid, transforming growth factor-beta and interferon-gamma in human dermal fibroblasts cultured in three-dimensional collagen gel are photoaging- and aging-independent

Decreased collagen synthesis and loss of responsiveness to growth factors are well known phenomena in in vivo or in vitro aged cells. Ascorbic acid and some cytokines such as transforming growth factor-beta and interferon-gamma are important regulators of collagen synthesis. To investigate the responsiveness of fibroblasts with regard to the photoaging and aging process, we examined the effect of ascorbic acid, TGF-beta, and IFN-gamma on collagen synthesis in dermal fibroblasts from three newborn foreskins (1 day old) and in both exposed and unexposed skin fibroblasts from 4 old individuals (60-76 years old) cultured in monolayer and in collagen gel. We demonstrated that basal levels of collagen synthesis decreased with increasing age. Photoaged fibroblasts in collagen gel showed greater basal collagen synthesis than aged fibroblasts in the same individuals, but similar basal collagen synthesis in monolayer cultures. Even though basal levels of collagen synthesis in collagen gel are downregulated in a photoaging- and aging-dependent manner, collagen synthesis by ascorbic acid in collagen gel, and by TGF-beta and IFN-gamma in both monolayer culture and collagen gel were regulated in a photoaging- and aging-independent manner. In monolayer culture, however, the responsiveness to ascorbic acid in newborn fibroblasts was greater than in photoaged and aged fibroblasts. Our results suggest that there are differences in collagen synthesis between photoaged and aged cells, depending on culture conditions. Responsiveness to ascorbic acid, TGF-beta and IFN-gamma related to collagen synthesis in photoaged and aged fibroblasts in collagen gel appears to be the same as in newborn fibroblasts, even though basal levels of collagen synthesis are downregulated in a photoaging- or aging-dependent manner.

General principles of wound healing

Wound healing is a complex process involving different biologic and immunologic systems. Despite improvements in diagnostics and therapy, wound failures remain a clinical problem. The approach to a nonhealed wound is an interdisciplinary challenge that should not be underestimated. Better understanding of the complex wound-healing cascade helps our approach to wound healing and its possible failure. Manipulations of the involved immunologic features offer future therapeutic strategies.

Mast cell clusters in pars tensa membranae tympani in acute otitis media: a possible role in perforation healing

Mast cells are known to reside in pars flaccida membranae tympani and other parts of the middle ear mucosa in both rats and humans. However, the normal pars tensa contains no or only a few mast cells along the manubrial vessels. We examined the pars tensa of 25 rats in an experimental model of acute otitis media and found 13 mast cell clusters in 6 membranes. A majority of clusters were located in the anterior, superior quadrant and contained from 3 to 23 cells. The mast cells resided immediately under the inner epithelial lining or in the intermediate, fibrous layer. In two membranes mast cell clusters were found in the margin of apparently healed spontaneous perforations. We conclude that mast cells in some cases infiltrate pars tensa membranae tympani in the late and receding phase of acute otitis media. As these cell clusters in some cases were found immediately around apparently healed membrane perforations, we propose that the mast cell might participate in the repair processes of tympanic membrane perforation healing. This is supported by recent studies in wound healing and functions of a number of mast cell mediators.