TGF-beta2 activates proliferative scar fibroblasts

BACKGROUND. Cytokines, such as the transforming growth factor beta (TGF-beta) isoforms, have been linked to the formation of proliferative scars. This study examines the stimulating effects of exogenous TGF-beta2 on cultured keloid, burn hypertrophic scar, and normal skin fibroblasts and whether such effects can be suppressed with TGF-beta2 antibody. METHODS. In vitro, the fibroblast-populated collagen lattice (FPCL) is used in the evaluation of fibroblast activation by measuring contraction of the lattice over time. Primary cultures of fibroblasts were grown from keloids, burn hypertrophic scars, and normal skin using standard cell culture techniques. TGF-beta2 (10 ng/ml) was added to each of the three types of cell cultures and placed on prefabricated FPCLs. Each was tested against their normal control counterparts. TGF-beta2 antibody (100 ng/ml) was then placed on the TGF-beta2-treated FPCLs. All lattices were allowed to contract and areas were measured for 5 days. RESULTS. Compared to controls, keloid fibroblasts were most affected by the addition of exogenous TGF-beta2. Normal skin fibroblasts did not show a significant increase in contraction early on, yet a significant difference was seen as time progressed. The addition of TGF-beta2 antibody inhibited the function of keloid and burn hypertrophic scar fibroblasts. It also reversed the increased contraction of the TFG-beta2-treated proliferative scar fibroblasts. CONCLUSION. By utilizing an in vitro model, we have demonstrated that TGF-beta2 antibody reverses the increased contraction of FPCLs by proliferative scar fibroblasts treated with TGF-beta2. This points to a possible treatment modality in patients afflicted with this disfiguring problem.     

增生性瘢痕和瘢痕疙瘩组织中TGF—β1及Ⅰ,Ⅲ型胶原基因 …

目的 检测增生性瘢痕（Ｈ）和瘢痕疙瘩（Ｋ）组织中ＴＧＦ－β１及Ⅰ、Ⅲ型前胶原ｍＲＮＡ的表达,了解其相互关系及意义。方法 斑点杂交分析检测Ｈ和Ｋ组织中Ⅰ、Ⅲ前胶原及ＴＧＦ－β１ｍＲＢＡ稳态水平的改变;原位杂交检测ＴＧＦ－β１ｍＲＮＡ在组织中的空间分布。结果 ①Ｋ和Ｈ组织中ＴＧＦ－β１ｍＲＮＡ稳态水平明显高于Ｎ组和Ｓ组;②Ｋ选择性Ｉ型前胶原ｍＲＮＡ表达增强,而Ｈ组织中Ⅰ、Ⅲ前胶原ｍＲＮＡ表达均增强。     

曲安奈德、干扰素α-2b和维拉帕米治疗增殖瘢痕的作用机制比较

目的 比较曲安奈德、干扰素α-2b和维拉帕米局部注射对瘢痕疙瘩和增生性瘢痕增殖、凋亡和TGF-β1表达的影响. 方法 增生性瘢痕和瘢痕疙瘩各6例,局部注射曲安奈德(40 mg/ml)、干扰素α-2b(150万U/ml)和维拉帕米(2.5 mg/ml)后7 d,切取标本,采用免疫组织化学、末端脱氧核苷酸介导的生物素化的脱氧尿嘧啶DNA切口末端标记方法,检测细胞增殖核抗原和TGF-β1的表达及细胞发生的凋亡情况,并以未注射药物的瘢痕疙瘩和增生性瘢痕以及健康皮肤为对照. 结果 ①曲安奈德可抑制瘢痕疙瘩和增生性瘢痕细胞增殖和诱导细胞凋亡,同时抑制细胞TGF-β1表达从而抑制瘢痕的增殖增生;②干扰素α-2b可通过抑制瘢痕疙瘩、增生性瘢痕细胞的增殖和TGF-β1表达而抑制瘢痕的增殖增生,但其不能诱导细胞凋亡;③维拉帕米可通过抑制瘢痕疙瘩、增生性瘢痕细胞的增殖和诱导细胞凋亡而抑制瘢痕的增殖,同时抑制细胞TGF-β1表达,其诱导细胞凋亡的作用妹强于曲安奈德,但抑制TGF-β1表达作用弱于曲安奈德和干扰素α-2b. 结论 曲安奈德、干扰素α-2b和维拉帕米局部注射后,对瘢痕疙瘩和增生性瘢痕在临床上虽均有效,但作用机制不尽相同.     

黑布药膏对兔耳增生性瘢痕成纤维细胞增殖的影响

目的：探讨黑布药膏对兔耳增生性瘢痕成纤维细胞增殖的影响。方法：成年大耳白兔24只,建立兔耳腹侧面增生性瘢痕模型,21天后,将瘢痕动物模型随机分为黑布药膏治疗组和瘢痕模型组,在黑布药膏治疗组瘢痕局部涂抹黑布药膏,每3天一次。在用药后第2、4、6、8周分别切取两组瘢痕组织,对比研究在瘢痕形成过程中黑布药膏对兔耳瘢痕成纤维细胞的影响。采用HE染色法观察瘢痕形态,计算瘢痕增生指数和成纤维细胞密度;采用免疫组化方法检测增殖细胞核抗原（PCNA）蛋白表达。结果：黑布药膏治疗组和模型对照组比较,PCNA蛋白表达明显减弱（P〈0.05）,光镜下见黑布药膏能明显抑制成纤维细胞增殖;黑布药膏能降低瘢痕增生指数和成纤维细胞密度,与模型对照组比较,差异有显著性意义（P〈0.05）。结论：黑布药膏可抑制兔耳增生性瘢痕成纤维细胞增殖。     

Increased TGF-β–producing CD4+ T lymphocytes in postburn patients and their potential interaction with dermal fibroblasts in hypertrophic scarring

The development of hypertrophic scar involves a complex interplay between cells and cytokines. Although the mechanism underlying its pathogenesis is not well understood, a polarized T-helper type 2 immune response has been reported, indicating a role for CD4+ T lymphocytes in hypertrophic scarring. Here, we report an increased frequency of CD4+/transforming growth factor-beta (TGF-beta)-producing T cells in the peripheral blood and hypertrophic scar tissue of burn patients. These cells may play an indirect regulatory role in hypertrophic scar by affecting the functions of dermal fibroblasts. Our results show an increase in cell proliferation and collagen synthesis by dermal fibroblasts treated with medium derived from burn patient CD4+ T lymphocytes but not from the CD4+ T cells of normal subjects. Using confocal microscopy and immunoblotting, we found the level of alpha-smooth muscle actin to be elevated in these treated dermal fibroblasts, which also showed an enhanced ability to contract collagen lattices. TGF-beta levels in medium conditioned by the culture of CD4+ T lymphocytes from burn patients were significantly higher than in the conditioned medium from CD4+ T lymphocytes of normal subjects. In addition, the application of a TGF-beta-neutralizing antibody significantly reduced the effect of burn patient CD4+ T lymphocyte medium on dermal fibroblast proliferation and collagen lattice contraction. Our study suggests that CD4+/TGF-beta-producing T lymphocytes may play an important role in postburn hypertrophic scarring.     

Temporal expression of the transforming growth factor-Beta pathway in the rabbit ear model of wound healing and scarring

BACKGROUND: Despite numerous studies that have investigated the cellular and molecular mechanisms underlying scar formation, this process still remains poorly understood. The importance of transforming growth factor-beta (TGF-beta) in these processes has been well recognized, and this study sought to define the temporal expression of the key members in this pathway in a well-established, clinically relevant, rabbit ear model of hypertrophic scarring. STUDY DESIGN: Seven-millimeter (hypertrophic) and 5-mm (nonhypertrophic) punch wounds were made on the ears of 12 rabbits. Wounds were harvested at days 0, 7, 15, 28, and 40. RESULTS: There were no appreciable histologic differences between the 5- and 7-mm wounds at days 7 and 15. At day 28, however, the 7-mm scars were considerably more hypertrophic compared with the 5-mm control scars (p<0.001). The mRNA levels of TGF-beta1 and collagen Ialpha2 were notably higher in the hypertrophic 7-mm scars at day 28 than in the nonhypertrophic 5-mm scars (p<0.03). Although not pronounced, levels of TGF-beta2 were higher in the hypertrophic scars. There were no other statistically significant differences between the 7- and 5-mm scars. CONCLUSIONS: Elevated levels of TGF-beta1, and possibly TGF-beta2, are associated with hypertrophic scar formation.     

The role of Th1/Th2 cell chemokine expression in hypertrophic scar

The aim of this study was to study the role of Th1/Th2 cell‐associated chemokines in the formation of hypertrophic scars in rabbit ears. Twenty‐six New Zealand white rabbits were used to establish the hypertrophic scar model of rabbit ear and the normal scar model of rabbit's back. Two rabbits were sacrificed on days 0 and 21, 28, 35, 42, 49, 56, and 63 after operation. The specimens were stained with haematoxylin‐eosin (HE). Scar elevation index (SEI) was used to detect the expression of 10 chemokines related to Th1/Th2 cells in both scar formation expressions. Real‐time polymerase chain reaction (PCR) results showed that two chemokines (CXCL10, CXCL12) were highly expressed during the formation of normal scar, and there was almost no expression during the formation of hypertrophic scar (*P < 0.05). The chemokines (CCL2, CCL3, CCL4, CCL5, CCL7, CCL13, CX3CL1) were almost non‐expressed in the formation of normal scars but were expressed for a long time in the formation of hypertrophic scars. The four chemokines, CCL2, CCL4, CCL5, and CX3CL1, maintained a long‐term high expression level during the formation of hypertrophic scars (P < 0.01). There were also three chemokines (CCL14, CCL19, CCL21) that were almost undetectable in normal scarring, but there was transiently low‐level expression (P < 0.05) only during the peak proliferative phase in proliferative scarring. Th1/Th2 cell‐associated chemokines are different in the type, quantity and expression, and maintenance time of rabbit ear hypertrophic scars.     

Pulsed dye laser therapy and z-plasty for facial burn scars: the alternative to excision

Hypertrophic scarring after partial thickness facial burns is common when epithelialization takes longer than 3 weeks. Well-healed areas continue to mature unfavorably, resulting in raised, erythematous, and contracted scars. Excisional treatment of such scars has morbidity and can create iatrogenic deformities. The flashlamp-pumped, pulsed dye laser (PDL) in combination with z-plasty can be used as a successful alternative to excision in patients with facial hypertrophic burn scars. Fifty-seven patients with hypertrophic facial burn scars (mean age 12 years; range, 2-21 years) were treated with the PDL over the past 8 years. Thirty-four patients (60%) were also treated with z-plasties to relieve scar tension. There was one complication of postoperative blistering. Patients were divided into 3 groups based on time from burn to initial laser treatment. Group I (<1 year) had 11 patients and the laser diminished scar proliferation in these patients. Group II (1-4 years) included 24 patients and treatment resulted in reversal of hypertrophic scarring and elimination of erythema. Group III (>5 years) consisted of 22 patients. The PDL was effective in treating their stable and persistent erythema as long as 17 years after burn injury. No scars required excision in this cohort of 57 patients. The PDL should become an integral part of the management of facial burn scarring and will significantly decrease the need for excisional surgery.     

Detection of apoptosis in keloids and a comparative study on apoptosis between keloids, hypertrophic scars, normal healed flat scars, and dermatofibroma

Recent studies have suggested that the regulation of apoptosis during wound healing is important in scar establishment and the development of pathological scarring. In this study, we demonstrate that keloid fibroblasts can be identified as apoptotic cells because of their highly condensed chromatin and discrete nuclear fragments. To further reveal the phenomenon of apoptosis, we quantified the number of terminal deoxynucleotide transferase-mediated dUTP nick-end labeling (TUNEL)-positive cells in surgically resected tissues of keloids (N = 10), hypertrophic scars (N = 10), normal healed flat scars (N = 10), and dermatofibroma (N = 10). The number of TUNEL-positive cells was relatively low, but was significantly higher for the keloid group compared with the normally healed flat scar group (p = 0.004), suggesting reduced cell survival and increased apoptotic cell death in a subpopulation of keloid fibroblasts. Furthermore, the number of TUNEL-positive cells was significantly higher for the keloid group compared with the dermatofibroma group (p = 0.044), suggesting that a subpopulation of keloid fibroblasts may suppress tumorgenicity at a greater rate than dermatofibroma by undergoing cell death. Hypertrophic scars had significantly higher levels of apoptosis than normally healed flat scars (p = 0.033). Therefore, these results suggest that selected fibroblasts in keloids and hypertrophic scars undergo apoptosis, which may play a role in the process of pathological scarring.     

CTGF在病理性瘢痕中的表达及意义

目的：了解细胞生长因子（connective tis sue growth factor，CTGF）在病理性瘢痕中的表达及意义，探讨它在病理性瘢痕发病机制中所起的作用.方法：对11例增生性瘢痕、10例瘢痕疙瘩及10例正常皮肤组织进行免疫组化（SP法）染色，观察CTGF在正常皮肤、增生性瘢痕、瘢痕疙瘩中的表达，以了解它们在不同组织中表达的差异性.结果：正常皮肤中CTGF的表达为阴性;增生性瘢痕、瘢痕疙瘩成纤维细胞中CTGF的表达与正常皮肤相比均有显著性差异（P＜0.01）;CTGF在瘢痕疙瘩成纤维细胞中的表达较增生性瘢痕为高，但两者之间没有统计学差异.结论：CTGF在增生性瘢痕的发病机制中发挥重要作用。     

Treatment of Postdermabrasion Facial Hypertrophic and Keloid Scars with Intralesional 5-Fluorouracil Injections

Hypertrophic and keloid scarring is a known complication of dermabrasion facial resurfacing, although only a very small fraction of patients experience it. Treatment with intralesional corticosteroid injections and flashed pumped vascular dye laser is recommended in the literature. The treatment of keloid and hypertrophic scars using intralesional 5-fluorouracil (5-FU) injections has been well described, but there is no literature regarding use of the same treatment for postdermabrasion hypertrophic and keloid scars. In this case report, we describe a 67-year-old woman with persistent postdermabrasion facial hypertrophic and keloid scars that were treated at our scar clinic using intralesional 5-FU injections.     

TGF-β和α-SMA在瘢痕组织中的表达及相关性研究

目的 检测转化生长因子－β（ＴＧＦ－β１,ＴＧＦ－β２,ＴＧＦ－β３）在增生性瘢痕和表浅性瘢痕中的表达,探讨其对增生性瘢痕的形成及α－平滑肌肌动蛋白（α－ＳＭＡ表达的可能作用。方法 采用免疫组化法检测２８例增生性瘢痕,１９例表浅性瘢痕和１６例正常皮肤组织中ＴＧＦ－β和α－ＳＭＡ的表达水平,并按年龄,性别,病程分组进行比较及ＴＧＦ－β和α－ＳＭＡ相关性分析。     

伍重道远:进一步加强瘢痕的基础与临床研究

Scar,either hypertrophic scar or keloid,is one of the most common complications due to proliferative disorder of fibrosis in the process of wound healing after burn injuries,trauma,and surgical operations.To repair the cosmetic and functional impairments caused by scars poses a great challenge to all the burn surgery workers.With the advances in both basic research and clinical treatment,the understanding of scar formation and the therapeutic strategies of scar have been improved significantly.However,the remaining problems are still outstanding.In this discussion,the advances and problems in the scientific research in this field,including genetic predisposition,candidate gene,dysfunction of fibroblasts,interaction between fibroblasts and keratinocytes,as well as animal models for hypertrophic scar and keloid were summarized.In addition,the progreses in the clinical therapies are also discussed,including pressure treatment,silicone gel sheeting,corticosteroids,laser,and other emerging treatment strategies.The understanding and treatment of scar will improve in the future with further deepening basic research and clinical trials with stricter standard of assessment.     

病理性瘢痕裸鼠模型的建立

目的 验证所构建裸鼠瘢痕疙瘩和增生性瘢痕模型在病理性瘢痕研究中的可行性。方法 将0．8cm×0．8cm×0．5cm的人瘢痕疙瘩和增生性瘢痕组织块移植到裸鼠皮下，大体观察裸鼠及植入物情况。移植后第16天取出移植物与原标本进行下列指标的比较：体积、瘢痕的镜下特征、酸性黏多糖含量及Ⅰ、Ⅱ型胶原含量。结果 移植后裸鼠全部存活且创面愈合良好。瘢痕疙瘩、增生性瘢痕组织块的酸性黏多糖含量移植前分别为3448±1452、1940±509，移植后分别为3237±1871、1809±552，移植前后比较，差异无统计学意义（P〉0．05）。植入物保持着原有的胶原特性及含量，未检测到细胞变性坏死。结论 增生性瘢痕和瘢痕疙瘩以适当体积移植到裸鼠皮下，其生物学特性可在一定时间内保持稳定，该动物模型适用于病理性瘢痕的临床研究。     

Scar formation following excisional and burn injuries in a red Duroc pig model

Scar research is challenging because rodents do not naturally form excessive scars, and burn depth, size, and location cannot be controlled in human longitudinal studies. The female, red Duroc pig model has been shown to form robust scars with biological and anatomical similarities to human hypertrophic scars. To more closely mimic the mode of injury, recreate the complex chemical milieu of the burn wound environment and enhance scar development, an animal model of excessive burn‐induced scarring was developed and compared with the more commonly used model, which involves excisional wounds created via dermatome. Standardized, full‐thickness thermal wounds were created on the dorsum of female, red Duroc pigs. Wounds for the dermatome model were created using two different total dermatome settings: ～1.5 mm and ≥ 1.9 mm. Results from analysis over 150 days showed that burn wounds healed at much slower rate and contracted more significantly than dermatome wounds of both settings. The burn scars were hairless, had mixed pigmentation, and displayed fourfold and twofold greater excess erythema values, respectively, compared with ～1.5 mm and ≥ 1.9 mm deep dermatome injuries. Burn scars were less elastic, less pliable, and weaker than scars resulting from excisional injuries. Decorin and versican gene expression levels were elevated in the burn group at day 150 compared with both dermatome groups. In addition, transforming growth factor‐beta 1 was significantly up‐regulated in the burn group vs. the ～1.5 mm deep dermatome group at all time points, and expression remained significantly elevated vs. both dermatome groups at day 150. Compared with scars from dermatome wounds, the burn scar model described here demonstrates greater similarity to human hypertrophic scar. Thus, this burn scar model may provide an improved platform for studying the pathophysiology of burn‐related hypertrophic scarring, investigating current anti‐scar therapies, and development of new strategies with greater clinical benefit.     

Intra-lesional injections of collagenase are ineffective in the treatment of keloid and hypertrophic scars.

The treatment of keloid and hypertrophic scars remains difficult. Enzymatic digestion of keloid scars has been previously proposed as an effective treatment strategy for reducing the volume of keloid scars. To test this, we administered intra-lesional injections of pure collagenase (between 600 and 4500 units for each scar) into the keloid and hypertrophic scars of seven human volunteers (five keloid and two hypertrophic scars). Five patients (three keloid and two hypertrophic) received more than one injection of collagenase. The treatment resulted in a temporary reduction in scar volume for three of the patients with keloid scars. However, scar volumes for these three patients returned to the same (or greater) levels after 6 months of follow-up. Treatment with collagenase produced no change in scar volume for the two patients with hypertrophic scar. Side effects were numerous and severe including; pain, swelling, blistering, ulceration and ecchymosis at the site of injection. One patient required admission to hospital for 48 h after the first injection. Maximum length of follow-up was 6 months. None of the seven patients completed the study and returned for final follow-up at 2 years. This pilot study suggests that treatment of keloid and hypertrophic scars with intra-lesional injections of collagenase is ineffective.     

性激素受体在瘢痕中的表达及与细胞周期调控蛋白相互关系的研究

目的　了解雄激素受体 (AR)、雌激素受体 (ER)在病理性瘢痕中的表达及其与细胞周期调节蛋白D1(cyclinD1)、p16之间的相互关系 ,以探讨他们在瘢痕形成过程中的作用及机制。方法　采用免疫组化方法 (SP法 )对 30例瘢痕标本进行研究 ,以正常皮肤组织为对照 ,观察上述指标的表达。结果　正常皮肤及普通瘢痕成纤维细胞中所有指标均为阴性 ;增生性瘢痕与瘢痕疙瘩成纤维细胞中cyclinD1、p16、AR与正常皮肤相比差异均有显著性意义 (P <0 0 5 ) ;瘢痕疙瘩成纤维细胞cyclinD1和AR的表达高于增生性瘢痕 ,且有显著性意义 (P <0 0 5 ) ;p16在瘢痕疙瘩成纤维细胞的表达比增生性瘢痕为高 ,但两者之间差异无显著性意义。在病理性瘢痕中cyclinD1和AR的表达具有明显的相关性。结论　AR在病理性瘢痕的发生及发展中起一定的作用 ,它可能是通过与其配体结合后促使与cyclinD1有关的基因表达而发挥作用的。在瘢痕疙瘩里可能存在cyclinD1的促细胞增生作用超过P16细胞抑制 ,所以细胞呈现持续增殖状态 ;而在增生性瘢痕里cyclinD1与p16可能处于相对的平衡状态 ,细胞生长具有一定的自限性。     

E2F1蛋白在病理性瘢痕组织中的表达

目的　增生性瘢痕和瘢痕疙瘩是临床上常见的病理性瘢痕 ,是创伤后过度愈合反应的结果 ,以成纤维细胞的异常增殖及合成分泌大量细胞外基质为特征 ,其形成机理尚不清楚 ,研究表明基因失调是其中的关键。E2F基因是细胞周期G1向S期过渡的重要调控因子 ,在调节细胞周期进程和调节细胞增殖过程中起着关键作用。本实验的目的是检测E2F1基因在病理性瘢痕组织中的表达 ,以正常皮肤组织做对照 ,初步探讨E2F1在病理性瘢痕形成中的生物学作用。方法　利用免疫组化ABC法检测正常皮肤、成熟瘢痕、增生性瘢痕和瘢痕疙瘩组织中E2F1蛋白的表达 ,并进行统计学分析。结果　增生性瘢痕和瘢痕疙瘩组织中E2F1蛋白表达两组间无明显差异 ,与正常皮肤、成熟瘢痕对照组比较均有显著性差异 (P <0 .0 1)。结论　E2F1蛋白表达在病理性瘢痕组织中增高 ,促进瘢痕组织中细胞的增生 ,对病理性瘢痕的形成可能起着重要作用     

Suppression of transforming growth factor beta/smad signaling in keloid-derived fibroblasts by quercetin: implications for the treatment of excessive scars

BACKGROUND: Keloids are characterized by abnormal proliferation and overproduction of extracellular matrix. Quercetin, a dietary compound, has strong antioxidant and anticancer properties. Previous studies by the authors have shown that quercetin inhibits fibroblast proliferation, collagen production, and contraction of keloid and hypertrophic scar-derived fibroblasts. Quercetin also blocks the signal transduction of insulin-like growth factor-1 in keloid fibroblasts. This study assessed the effects of quercetin on the transforming growth factor (TGF)-beta/Smad-signaling pathway in keloid-derived fibroblasts, which may be an important biologic mechanism of this proliferative scarring. METHODS: Keloid fibroblasts were isolated from keloid tissue specimens. Cells were treated with quercetin at different concentrations, then harvested, and subjected to immunoblotting analysis. RESULTS: Quercetin significantly inhibited the expression of TGF-beta receptors 1 and 2 in keloid fibroblasts at three concentrations (low, medium, and high). Quercetin also strongly suppressed the basal expression of Smad2, Smad3, and Smad4 as well as the phosphorylation of Smad2 and Smad3 and the formation of the Smad2-Smad3-Smad4 complex. CONCLUSIONS: Taken together, these data suggest that quercetin effectively blocks the TGF-beta/Smad-signaling pathway in keloid fibroblasts. These data indicate that quercetin-based therapies for keloids should be investigated further.     

595nm激光对兔耳瘢痕成纤维细胞增殖与凋亡的影响

目的：探讨595nmVbeam激光照射对增生性瘢痕动物模型伤口愈合过程中成纤维细胞增殖与凋亡的影响。方法：成年大耳白兔20只,建立兔耳腹侧面增生性瘢痕模型,对比研究在瘢痕形成过程中595nmVbeam激光照射对兔耳瘢痕成纤维细胞的影响,采用免疫组化方法检测增殖细胞核抗原（PCNA）蛋白表达和细胞凋亡的原位检测。结果：兔耳增生性瘢痕经595nmVbeam激光照射后,按不同时间段取材进行免疫组化染色并与对照组比较,高倍镜下观察结果,显示PCNA蛋白表达明显减弱,细胞凋亡增加。结论：595nmVbeam激光照射可抑制兔耳增生性瘢痕成纤维细胞的增殖过程,诱导细胞凋亡。应用595nmVbeam激光预防和治疗瘢痕是可行的。