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The structural rearrangement of collagen fibres in hypertrophic scar causes abnormal contracture, low tensile strength, and raised scars, which cause functional impairment and disfigurement. It is hypothesized that changes in the genes of cytokines, extracellular matrix proteins, and proteins regulating programmed cell death are related to hypertrophic scar formation. To test this hypothesis, fibroblasts were cultured from hypertrophic scars and their response to interleukin-6 (IL-6) stimulation was studied by defining their gene expression profiles. Affymetrix gene chip analysis was used to identify up- or down-regulation in the 12 625 genes present in the affymetrix array. RT-PCR and ELISA assays were used to validate microarray expression profiles further. Comparison of gene profiles showed an increase of 12 genes in hypertrophic scar fibroblasts compared with normal skin fibroblasts, while the expression of 14 genes decreased. Thirty-three genes were affected by IL-6 treatment in the hypertrophic scar fibroblasts, while 57 genes were affected in normal skin fibroblasts. Messenger RNA to beta-actin ratios for matrix metalloproteinase-1 (MMP-1) and MMP-3 were increased with IL-6 in normal skin fibroblasts from 2.43 +/- 0.06 to 5.50 +/- 0.45 and from 0.75 +/- 0.09 to 1.98 +/- 0.01, respectively. No change in these matrix metalloproteinases could be shown with IL-6 stimulation in hypertrophic scar fibroblasts. Secreted protein levels of pro-MMP-1 and MMP-3 were elevated in the supernatants from normal skin fibroblasts from 2.00 +/- 0.09 and 1.72 +/- 0.10 ng/ml to 4.60 +/- 0.12 and 3.41 +/- 0.20 ng/ml, respectively, after treatment with IL-6 (p < 0.05). No changes were observed in hypertrophic scar fibroblasts treated with IL-6. Values are means +/- SEM. The absence of any up-regulation of MMP-1 and MMP-3 in hypertrophic scar fibroblasts, in response to IL-6, suggests that suppression of matrix metalloproteinases may play a role in the excessive accumulation of collagen formed in hypertrophic scars. While the pathogenesis of abnormal hypertrophic scars remains poorly understood, the use of gene expression arrays may prove helpful in identifying the mechanisms responsible for this type of abnormal scar formation and in formulating an effective therapeutic protocol., (Copyright 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.)

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)-1β 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-1β indicate that 15 genes increased and 8 genes decreased expression. When normal skin was stimulated with IL-1β, there were increases in the expression of heat shock transcription factor-1, hsp70, and IL-6 When hypertrophic scar was stimulated with IL-1β, there was a decrease in nuclear factor-κB, GADD45-α, 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-1β, may be important mediators of abnormal scarring. [Copyright &y& Elsevier]

In this study, we investigated the effect of inflammatory cytokines on matrix metalloproteinase (MMP-1) and TIMP-1 production in human dermal fibroblasts, which play a pivotal role in wound healing, ranging from the synthesis and remodeling of extracellular matrix (ECM) to the synthesis of growth factors. The balance of MMPs and TIMPs is crucial in directing successful wound repair. Human adult dermal fibroblasts were seeded in six well plates (7.5×104 cells/ml) in complete media. Eighty to ninety percent confluent cells were treated with interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) (10 ng/ml) for 6 h in serum free media with suitable controls run in triplicate. Supernatants were assayed for pro-MMP-1 & TIMP-1. Extracted total RNA was used for reverse transcription polymerase chain reaction (RT-PCR) with sequence specific primers for MMP-1, TIMP-1 and β-actin. Signal intensity was normalized to the internal control (β-actin). Statistical analysis used ANOVA. MMP-1 and TIMP-1 mRNA expression were markedly increased with IL-6 and TNF-α treatment and remains unchanged with IL-1β. Pro-MMP-1 protein levels are unchanged with TNF-α and significantly increased with IL-1β and IL-6 treatment. However, TNF-α significantly increases TIMP-1 protein levels. Data suggests differential regulation of MMP-1 and TIMP-1 protein levels by the cytokines found in stimulated dermal fibroblasts. Further characterization of this response will provide an understanding of the mechanisms of pathogenesis of extracellular matrix (ECM) and the potential role of metalloproteinases in tissue remodeling after injury. [Copyright &y& Elsevier]