Gene expression profiles from hypertrophic scar fibroblasts before and after IL-6 stimulation

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.     

Keratinocyte-derived growth factors play a role in the formation of hypertrophic scars

In predisposed individuals, wound healing can lead to hypertrophic scar or keloid formation, characterized by an overabundant extracellular matrix. It has recently been shown that hypertrophic scars are accompanied by abnormal keratinocyte differentiation and proliferation, and significantly increased acanthosis, compared with normal scars. This study addressed the question of whether the development of normal and hypertrophic scars is regulated by differences in the growth factor profiles of both the epidermis and the dermis. The presence of interleukin-1alpha (IL-1alpha), IL-1beta, tumour necrosis factor-alpha (TNF-alpha), platelet-derived growth factor (PDGF), transforming growth factor-beta1 (TGF-beta1), and basic fibroblast growth factor (bFGF) was investigated in biopsies taken from breast reduction scars at 3 and 12 months following surgery. The samples were analysed by immunohistological methods and categorized as scars that remained hypertrophic (HH), became normal (HN) or remained normal after 12 months (NN). The epidermal expression of IL-1alpha was significantly increased in NN scars compared with HN and HH scars 3 and 12 months following operation, whereas the dermal expression showed no difference. PDGF was significantly increased in the dermis of normal scars after 3 months and in both the epidermis and the dermis of hypertrophic scars after 12 months. IL-1beta, TNF-alpha, TGF-beta and bFGF showed no differences. It is hypothesized that impaired production of keratinocyte-derived growth factors, such as IL-1alpha, leads to a decrease in the catabolism of the dermal matrix, whereas augmented epidermal PDGF production leads to increased formation of the dermal matrix in hypertrophic scars. These observations support the possibility that the epidermis is involved in preventing the formation of hypertrophic scars.     

Hypertrophic scar formation is associated with an increased number of epidermal Langerhans cells

The exact pathogenesis of hypertrophic scar and keloid formation is still unknown and a good therapy to prevent or treat these scars is lacking. Because immunological processes seem to be important in excessive scar formation, immunological cells and parameters were studied in a standardized breast reduction wound-healing model in the present study. Standardized scar samples were taken from infra-mammary breast reduction scars, 3 and 12 months following surgery. The samples were investigated for their number of mast cells, Langerhans cells, T-lymphocytes, and macrophages, and the presence of interleukin-4 (IL-4) and counter-regulating interferon-gamma (gamma-IFN), in relation to the scar's clinical appearance--normal or hypertrophic. In this study, hypertrophic scar formation was significantly associated with an increased number of epidermal Langerhans cells (p=0.0001) and significantly (p<0.05) increased expression of epidermal IL-4. No relationship was found between mast cell, T-lymphocyte and macrophage numbers or gamma-IFN staining and the formation of normal or hypertrophic scars. These results, combined with previous observation of abnormal keratinocyte behaviour in this context, indicate that the epidermal immune barrier plays an important role in the development of hypertrophic scars.     

病理性瘢痕中胰岛素样生长因子1及受体mRNA的表达

背景：多种肿瘤中胰岛素样生长因子1受体及其配体表达异常,且胰岛素样生长因子1是多种细胞的有丝分裂原和抗细胞凋亡的因子,控制多种细胞的增殖、分化和凋亡的进程。 目的：观察胰岛素样生长因子1及胰岛素样生长因子1受体在病理性瘢痕中的表达。 方法：收集中山大学附属第一医院烧伤外科收治患者增生性瘢痕、瘢痕疙瘩及其正常皮肤等手术切除标本,荧光定量实时PCR检测不同组织中胰岛素样生长因子1及其受体mRNA的表达水平。 结果与结论：瘢痕疙瘩及增生性瘢痕中胰岛素样生长因子1 mRNA表达水平均高于正常皮肤(P < 0.05),且在瘢痕疙瘩及增生性瘢痕组织中胰岛素样生长因子1表达水平差异无显著性意义(P > 0.05),胰岛素样生长因子1受体在增生性瘢痕表达水平与正常皮肤接近(P > 0.05);而瘢痕疙瘩中胰岛素样生长因子1受体明显高于瘢痕周围正常皮肤(P < 0.05)。说明胰岛素样生长因子1及其受体在病理性瘢痕的形成过程中起重要作用。     

基质金属蛋白酶13和转化生长因子β1在瘢痕疙瘩和增生性瘢痕中的表达

背景：与瘢痕疙瘩和增生性瘢痕发生机制相关的基质金属蛋白酶13和转化生长因子β1信号传递通路研究多集中在体外成纤维细胞的培养上,而在组织中的相关研究少见报道。 目的：观察瘢痕疙瘩和增生性瘢痕中基质金属蛋白酶13和转化生长因子β1蛋白的表达。 方法：取自2004/2008唐山市工人医院烧伤整形科手术患者,瘢痕疙瘩54例,增生性瘢痕42例。选取同期45例因非感染手术切除的正常瘢痕组织作为对照组,选取同期45例正常皮肤组织作为正常对照组。应用流式细胞仪检测4组中基质金属蛋白酶13和转化生长因子β1的表达,分析两者的相关性。 结果与结论：瘢痕疙瘩和增生性瘢痕中转化生长因子β1的表达明显高于正常瘢痕组织和正常皮肤组织;正常瘢痕组织中转化生长因子β1的表达明显则高于正常皮肤组织,而基质金属蛋白酶13的表达与之相反。瘢痕疙瘩、增生性瘢痕和正常瘢痕组织中基质金属蛋白酶13和转化生长因子β1表达呈负相关。由此推测基质金属蛋白酶13和转化生长因子β1在瘢痕组织中异常表达,二者可能具有协同负向作用,共同参与病理性瘢痕的发生发展。     

Vascularization pattern in hypertrophic scars and keloids: a stereological analysis

Wound healing is a complex process that does not always occur harmoniously and may lead to pathological scar development, such as hypertrophic scars and keloids. Considering that vascularization can play a role in the development of these scars, and that the literature is controversial, we performed a stereological analysis of dermal for vessels of normal skin, normal scars, hypertrophic scars, and keloids. The parameters studied concerned vessels: surface density, length density; for vessels and myofibroblasts: volume density, in papillary and reticular dermis. The pattern of dermal vascularization in normal skin and normal scar showed no differences. In papillary demis, the number of vessels was higher in hypertrophic scars and keloids than in normal skin (p < 0.05). Vessels of hypertrophic scars were more dilated than those of normal skin (p < 0.01). In reticular dermis, vessels were present in higher amount in hypertrophic scars and keloids than in normal skin (p < 0.025; p < 0.001, respectively). The pattern of vascularization did not show any differences between hypertrophic scars and keloids. Our results show that hypertrophic scars and keloids have a distinct pattern of vascularization compared to normal skin and normal scars. This indicates that abnormal vascularization can be involved in the development of hypertrophic scars and keloids.     

Glycosaminoglycans of normal and hypertrophic human scar

The glycosaminoglycan (GAG) contents of hypertrophic scars, normal scars, and human skin from cadavers of matched ages were compared. Cellulose acetate electrophoresis, chondroitinase digestions, and reaction product and infrared analyses were used to characterize the component GAGs. DEAE-cellulose chromatography was used to separate hyaluronic acid (HA) and sulfated GAGs. Chondroitinase analysis was improved under these conditions. HA was determined enzymatically. Results showed an elevation of HA in hypertrophic scar. Dermatan sulfate was the major GAG in both scars and a slightly greater quantity was observed in the hypertrophic scar. Small amounts of chondroitin 4-sulfate and chondroitin 6-sulfate disaccharide constituents were also detected by the chondroitinase assay method and these were also elevated in hypertrophic scar. These results suggest that the GAGs of hypertrophic scar differ from normal scar and normal skin.     

Contribution of epidermal stem cells to hypertrophic scars pathogenesis

Hypertrophic scars are fibroproliferative disorders of excessive wound healing due to an imbalance between synthesis and degradation and the mechanism leading to hypertrophic scars formation is poorly understood and currently no successful treatment modality exists.We hypothesize epidermal stem cells (ESCs), which could inhibit epidermal fibrosis, plays a substantial contributory role in the pathogenesis of hypertrophic scars.Accepting the hypothesis to be correct, a therapy that inhibits cell and extracellular matrix proliferation can be used to prevent the hypertrophic scars formation.Current therapies are only partially effective and safe because they couldn’t inhibit the cell and extracellular matrix proliferation and eliminate other relative factors of hypertrophic scars formation at all, such as: absence of epidermal–mesenchymal interaction, and at the same time inducing death (apoptosis and necrosis) of other normal cells.A more efficient prevention of hypertrophic scars could be achieved using tissue engineering skin enriched with ESCs and introduced recombinant genes into ESCs which could inhibit hypertrophic scars formation.     

腺苷A2A受体基因敲除小鼠瘢痕胶原亚型的变化

背景：作者前期研究发现腺苷受体激动剂可以刺激胶原合成,腺苷受体拮抗剂可以抑制胶原合成,并且可以减轻皮肤胶原纤维增生。腺苷A2A 受体基因敲除小鼠瘢痕转化生长因子β表达降低。 目的：利用苦味酸-天狼星红偏振光法观察腺苷A2A 受体基因敲除小鼠瘢痕胶原亚型的变化并探讨其机制。 方法：腺苷A2A受体基因敲除小鼠和野生型小鼠制作瘢痕模型,采用苦味酸-天狼星红偏振光法对瘢痕组织中胶原的性质及分布特点进行观察、确定瘢痕组织胶原类型、分布、排列与水平。 结果与结论：偏振光显微镜下可见野生型组小鼠增生性瘢痕组织中含有大量的嗜酸性胶原蛋白纤维束,Ⅰ型胶原纤维为红色,呈致密的条束状,显示很强的双折光性,腺苷A2A 受体基因敲除小鼠瘢痕缺乏粗大胶原束,呈稀疏的条束状,排列相对整齐、密度较为均匀,Ⅰ型胶原纤维水平减少(P < 0.01),瘢痕增生显著减轻。提示腺苷A2A 受体参与瘢痕增生,对预防瘢痕增生有积极意义。     

Epidermal participation in post-burn hypertrophic scar development

 The reconstruction of epidermal architecture over time in normotrophic and hypertrophic scars in untransplanted, spontaneously healed partial-thickness burns has scarcely been studied, unlike the regeneration of epidermal grafts used to cover burn wounds and the regeneration of the dermis during hypertrophic scarring. The expression of markers of epidermal proliferation, differentiation and activation in normotrophic and hypertrophic scars in spontaneously healed partial-thickness burns was assessed and compared with the expression of these markers in normal control skin of healthy persons to determine whether hypertrophic scarring is associated with abnormalities in the phenotype of keratinocytes. Punch biopsies were taken both of partial-thickness burns after re-epithelialisation and of matched unburned skin. At 4 and 7 months post-burn, biopsies were taken of normotrophic and hypertrophic scars that had developed in these wounds. The biopsies were analysed using immunostaining for markers of keratinocyte proliferation, differentiation and activation (keratins 5, 10, 16 and 17, filaggrin, transglutaminase and CD36). We observed a higher expression of markers for proliferation, differentiation and activation in the epidermis of scars at 1 month post-burn than in normal control skin of healthy persons. There was a striking difference between normotrophic and hypertrophic scars at 4 months post-burn. Keratinocytes in hypertrophic scars displayed a higher level of proliferation, differentiation and activation than did normotrophic scars. At 7 months post-burn all keratinocyte proliferation and differentiation markers showed normal expression, but the activation marker CD36 remained upregulated in both normotrophic and hypertrophic scars. Surprisingly, in matched unburned skin of burn patients, a state of hyperactivation was observed at 1 month. Our results suggest that keratinocytes may be involved in the pathogenesis of hypertrophic scarring. Received: 16 September 1998 / Accepted: 28 September 1998     

Smad交互蛋白1在增生性瘢痕组织中的表达及其对纤维化相关因子的影响

目的研究Smad交互蛋白1（SIP1）在人增生性瘢痕组织中的表达及其对纤维化相关因子的影响。方法收集临床整形手术切取的9例患者增生性瘢痕标本及其自体正常皮肤标本。分离培养原代人增生性瘢痕成纤维细胞（HSFBs）,取第3-5代细胞用于实验。（1）免疫组织化学法检测增生性瘢痕组织标本及其自体正常皮肤组织标本中SIP1的表达情况。（2）真核表达质粒pcDNA3.1（＋）/SIP1转染HSFBs。按照随机数字表法将细胞分为6组：对照组;pcDNA3.1（＋）组（空载体组）;pcDNA3.1（＋）/SIP1组;对照＋TGF-β1组;pcDNA3.1（＋）＋TGF-β1组;pcDNA3.1（＋）/SIP1＋TGF-β1组。于转染后第48 h和72 h分别提取细胞总RNA和细胞总蛋白。应用实时荧光定量PCR法检测各组细胞α平滑肌肌动蛋白（α-SMA）及结缔组织生长因子（CTGF）的mRNA表达水平;采用Western-blotting检测α-SMA的蛋白表达水平。结果 （1）免疫组织化学染色结果显示：增生性瘢痕组织中SIP1表达明显低于自体正常皮肤组织。（2）pcDNA3.1（＋）/SIP1转染HSFBs后纤维化相关因子的表达：①α-SMA的mRNA和蛋白表达水平：与对照组和pcDNA3.1（＋）组相比,pcDNA3.1（＋）/SIP1组在mRNA和蛋白表达水平均显著下调,差异有统计学意义（P〈0.05）。当细胞给予TGF-β1刺激后,各组α-SMA表达均上调,但pcDNA3.1（＋）/SIP1＋TGF-β1组mRNA和蛋白表达水仍低于对照＋TGF-β1组,差异有统计学意义（P〈0.05）。②CTGF的mRNA表达水平：与对照组和pcDNA3.1（＋）组相比,pcDNA3.1（＋）/SIP1组在mRNA表达水平显著下调,差异有统计学意义（P〈0.05）。当细胞给予TGF-β1刺激后,各组CTGF表达均显著上调,但pcDNA3.1（＋）/SIP1＋TGF-β1组mRNA表达水仍低于对照＋TGF-β1组,差异有统计学意义（P〈0.05）。结论与正常皮肤组织相比较,SIP1在增生性瘢痕组织中低表达。SIP1基因转染HSFBs可降低纤维化相关因?     

单核细胞趋化蛋白1和骨形成蛋白7在病理性瘢痕中的表达

背景：单核细胞趋化蛋白1是新近明确的对单核/巨噬细胞有趋化和激活双重作用的趋化因子,骨形成蛋白7作为一种新发现的纤维化负性调节因子逐渐成为抗组织纤维化治疗的研究热点,但两者对病理性瘢痕形成中组织纤维化作用的研究至今鲜有报道。 目的：研究单核细胞趋化蛋白1,骨形成蛋白7在病理性瘢痕中的表达水平。 方法：采用免疫组织化学方法检测单核细胞趋化蛋白1、骨形成蛋白7在25例瘢痕疙瘩、30例增生性瘢痕、24例非病理瘢痕和20例正常皮肤组织中的表达水平。所有标本均来自2008-07/2010-01郑州大学第一附属医院整形外科住院患者,且均无皮肤疾病、结缔组织病、传染病、恶性肿瘤和其他重要脏器疾病,术前无射线治疗、激光治疗及免疫治疗史,其中所取瘢痕组织来自于临床诊断明确的瘢痕患者。 结果与结论：单核细胞趋化蛋白1在瘢痕疙瘩、增生性瘢痕中的阳性表达率均高于非病理性瘢痕与正常皮肤组织(P < 0.05),骨形成蛋白7阳性表达率均降低(P < 0.05),两者阳性表达率在病理性瘢痕(瘢痕疙瘩和增生性瘢痕)中呈明显负相关(r = -0.639,P < 0.01)。结果显示,在病理性瘢痕的形成过程中单核细胞趋化蛋白1表达上调,而骨形成蛋白7表达下调。      

增生性瘢痕成纤维细胞中CyclinD1，CDK2，CDK4作用及与 细胞周期的相关性

背景：增生性瘢痕的发生和发展可能与细胞周期调节相关基因的异常表达有关。 目的：检测增生性瘢痕不同阶段细胞CyclinD1、CDK2和CDK4 mRNA及蛋白的表达,以及同一标本增生性瘢痕成纤维细胞的细胞周期运行中3者之间的一致性。 方法：采集32份增生性瘢痕标本,以增生性瘢痕形成时段分为3个月组、6个月组、1年组、2年组,各8份,并以8份正常真皮标本作为对照。利用实时荧光定量PCR法、Western blotting法检测标本中CyclinD1、CDK2、CDK4 mRNA及蛋白表达,流式细胞术检测成纤维细胞的细胞周期。 结果与结论：增生性瘢痕标本发展过程中CyclinD1、CDK2、CDK4 mRNA及蛋白表达水平由强至弱变化。3,6个月增生性瘢痕中成纤维细胞主要分布在S、G2 /M期;1,2年增生性瘢痕与对照组成纤维细胞多处于G0/G1期。表明增生性瘢痕不同时期CyclinD1、CDK2、CDK4各自的 mRNA和蛋白表达趋势基本一致,同时增生性瘢痕中成纤维细胞的细胞周期分布与这3个蛋白所执行的功能情况相对应。     

Smad泛素化调节因子-2及其mRNA在增生性瘢痕组织中的表达

目的研究烧伤后增生性瘢痕组织中Smad泛素化调节因子－2（Smurf2）及其mRNA的表达。方法选取烧伤后增生性瘢痕患者9例,取材于患者整形手术切除的瘢痕,同时取同一患者剩余正常皮肤作为对照。Western blotting方法检测smurf2蛋白水平,RT—PCR检测其mRNA表达;进一步分离培养人正常皮肤和增生性瘢痕成纤维细胞,加入外源件转化生长凶子β1（TGF—β1）刺激,观察Smurf2蛋白和mRNA水平的变化。结果增生性瘢痕组织中Smurf2蛋白水平和mRNA表达显著高于正常皮肤（P〈0．05）,而且,在外源性TGF—β1刺激下,瘢痕成纤维细胞中Smurf2蛋白和mRNA表达呈时间依赖性增加。结论烧伤后增生性搬痕组织中Smurf2及其mRNA表达增强;在TGF—β1刺激下,瘢痕成纤维细胞中Smurf2及儿mRNA表达逐渐增加。     

Increased fibronectin production by cell lines from hypertrophic scar and keloid

Primary cell lines of fibroblasts from 8 tissues were established--three from hypertrophic scars (HS), one keloid (K) and four from the normal uninvolved dermis adjacent to each lesion. The objective was to quantify and compare all eight cell lines on the basis of fibronectin (FN) produced per cell and per total protein (PR). Two hypertrophic scars and their adjacent skin cell lines were evaluated by the ELISA method for FN and a micro Lowry assay for PR. The scar lines showed statistically significant increases in the amount of FN/cell compared to the cell lines from their adjacent normal dermis. The third hypertrophic scar and the keloid with their adjacent skin cell lines were assayed for FN and PR by radioimmunoprecipitation. Subconfluent cells were metabolically labeled with 35S-methionine for 20 hours. Harvested media and cell monolayers were assayed for radioactivity incorporated into FN and PR. The percentage of FN/PR was significantly higher in media for HS and K compared to the adjacent normal skin lines in the three passages tested. These results support our previous immunofluorescence studies and demonstrate that a fibroblast-type cell line from a hypertrophic scar or keloid produces more FN/PR over time than the normal fibroblast-type cell line from adjacent uninvolved dermis.     

Endothelial dysfunction may play a key role in keloid and hypertrophic scar pathogenesis – Keloids and hypertrophic scars may be vascular disorders

Keloids and hypertrophic scars are fibroproliferative disorders (FPDs) of the skin that result from abnormal healing of injured or irritated skin. They can be called pathological or inflammatory scars. Common causes are trauma, burn, surgery, vaccination, skin piercing, folliculitis, acne, and herpes zoster infection. The pathogenesis of these scars clearly involves local conditions such as delayed wound healing, wound depth, and the tension of the skin around the scars. Scar severity is also shaped by interactions between these local factors and genetic and systemic factors such as hypertension and sex hormones. Notably, to evaluate scar severity, the Japan Scar Workshop (JSW) has established the JSW Scar Scale.Our studies show that tension on the skin around the wound results in prolonged and/or repeated bouts of inflammation in the reticular layer of the dermis and that this inflammation generates abnormal numbers of blood vessels (as well as collagen and nerve fibers) in the dermal reticular layer. We hypothesize that local factors, such as the mechanobiology of the dermis and blood vessels, along with genetic and systemic factors promote pathological scar development by inducing endothelial dysfunction (i.e., vascular hyperpermeability) during the inflammatory stage of wound healing. The continued presence of these factors prolongs the influx of inflammatory cells and factors, thereby leading to fibroblast dysfunction.Evidence for this hypothesis includes the fact that all effective treatments of keloids, namely, radiotherapy, compression therapy, steroid administration, and long-pulsed Nd:YAG laser therapy, act, at least partly, by suppressing blood vessels.At present, keloids are classified as strongly inflammatory scars, while hypertrophic scars are considered to be mildly inflammatory scars. However, we propose that keloids and hypertrophic scars are simply manifestations of the same skin FPD and differ only in the degree of endothelial dysfunction and therefore inflammation. We therefore suggest that these pathological scars should be classified on the basis of the factor that causes the endothelial dysfunction. Thus, primary scars are caused by congenital endothelial dysfunction (e.g., a mutation prevents endothelial gaps from closing smoothly) while secondary scars are caused by endothelial dysfunction that results from aging, arterial sclerosis, and/or repeated/very strong local mechanical forces. We expect that primary keloids develop at younger ages and tend to become severe, while secondary keloids are seen in all ages and can vary in clinical severity.Thus, abnormal blood vessel regulation may underlie keloid and hypertrophic scar pathogenesis, which suggests that inhibiting abnormal angiogenesis and vascular hyperpermeability may be an important therapeutic approach.     

Expression of class II HLA antigens (HLA-DR, DQW1, DQW3) in normal skin and cutaneous pathology

We report the cutaneous expression of class II HLA antigens disclosed by immunohistochemical staining of normal and lesional skin with monoclonal antibodies (MoAbs) reacting with HLA-DR, DQW1 and DQW3 antigens. Briefly, we disclosed: on normal human skin: 1) The Langerhans cells (LC) HLA-DR+, DQW1+; 2) the acrosyringium HLA-DR+, DQW1+, DQW3+; 3) the dermal vessel endothelial cells HLA-DR+. On lesional skin: 1) The LC were found HLA-DQW3+ in the lesional skin of some cutaneous diseases; this expression was never shown on LC of normal human skin; 2) the epidermal keratinocytes disclosed an uniform membrane expression of HLA-DR antigens in some cutaneous diseases; this kind of expression was not found by immunostaining with MoAbs directed against HLA-DQ antigens; 3) in psoriatic lesions some keratinocytes disclosed an heterogeneous expression of HLA-DR, DQW1 and DQW3 antigens; 4) tumoral cells from cutaneous malignant melanomas were shown to be HLA-DR+, DQW1+, DQW3+. The HLA-DQW3 expression on the LC of lesional skin is in favour with a modulation of HLA-DQW3 expression by unknown factors present in pathological skin. The HLA-DR expression on epidermal keratinocytes suggests a functional collaboration of keratinocytes with LC in the genetic restriction of cutaneous immune reactions.     

Activated keratinocytes in the epidermis of hypertrophic scars.

The etiology of hypertrophic scarring, a pathological end point of wound healing, is unknown. The scars most commonly occur when epithelialization has been delayed during, for example, the healing of deep dermal burn wounds. Hypertrophic scars are conventionally described as a dermal pathology in which the epidermis has only a passive role. In this study, the expression of keratin intermediate filament proteins and filaggrin has been investigated in the epidermis of hypertrophic scars and site-matched controls from the same patients. Hypertrophic scar epidermis was found to express the hyperproliferative keratins K6 and K16 in interfollicular epidermis in association with K17 and precocious expression of filaggrin. K16 mRNA was localized by in situ hybridization using a highly specific cRNA probe. In contrast to the immunohistochemical location of K16 protein, the K16 mRNA was found to be expressed in the basal cell layer of normal skin. In hypertrophic scars the mRNA distribution corroborated the abnormal K16 protein distribution. These results suggest the keratinocytes in hypertrophic scar epidermis have entered an alternative differentiation pathway and are expressing an activated phenotype. Activated keratinocytes are a feature of the early stages of wound healing producing growth factors that influence fibroblasts, endothelial cells, and the inflammatory response. We propose that cellular mechanisms in the pathogenesis of hypertrophic scarring are more complex than isolated dermal phenomena. The persistence of activated keratinocytes in hypertrophic scar epidermis implicates abnormal epidermal-mesenchymal interactions.     

Immunohistochemical localization of the proteoglycans decorin, biglycan and versican and transforming growth factor-β in human post-burn hypertrophic and mature scars

The distributions of the small proteoglycans, decorin and biglycan and the large proteoglycan, versican, in normal skin and post-burn hypertrophic and mature scars, were compared using monoclonal and polyclonal antibodies to the core proteins. Biglycan and verscan were virtually undetectable in normal dermis but readily seen in hypertrophic scars. Staining for decorin was strong throughout the dermis in normal skin but restricted to the deep dermis and a narrow zone under the epidermis in hypertrophic scar—areas which did not stain for versican. Decorin was absent or reduced in the nodules in these specimens. In mature post-burn scars, staining for all three proteoglycans demonstrated an intensity that was intermediate between that in normal dermis and that in the nodules of the hypertrophic scars. Transforming growth factor-β was present in the nodules of hypertrophic scars but the deep dermis of these specimens stained most intensely for this cytokine which was also found in the dermis of mature scars but was not detectable in normal dermis. The apparent co-distribution of decorin and transforming growth factor-β suggests that this proteoglycan may play an active role in the resolution of the scars. Changes in proteoglycan type and distribution could possibly account, at least in part, for the derangement of collagen and the altered physical properties of hypertrophic scar tissue.     

深Ⅱ度烧伤愈合后Bcl-xl、Bax蛋白表达与增生性瘢痕的相关性

目的探讨Bcl-xl和Bax蛋白在深Ⅱ度烧伤愈合后不同时期增生性瘢痕中的表达特点。方法人深Ⅱ度烧伤愈合后不同时期的增生性瘢痕皮肤40例,正常皮肤组织10例。分为增生期组、减退早期组、减退晚期组、成熟期组,正常对照组。免疫组织化学染色,检测Bcl-xl和Bax蛋白的表达。结果深Ⅱ度烧伤创面愈合后,Bcl-xl和Bax蛋白主要表达于表皮基底细胞和真皮层成纤维细胞,增生期和减退早期Bcl-xl和Bax蛋白产物光密度值明显高于正常皮肤(p<0.01),减退晚期和成熟期随瘢痕成熟而逐渐递减接近正常皮肤。结论 Bcl-xl和Bax蛋白表达与深Ⅱ度烧伤创面愈合后增生性瘢痕的发生和瘢痕成熟相关。