自体头皮与脱细胞异体真皮复合移植修复巨大色素痣北大核心CSCD

目的 探讨自体头皮与脱细胞异体真皮复合移植方法修复儿童巨大色素痣的效果.方法 采用自体刃厚头皮与脱细胞异体真皮复合移植的方法修复儿童巨大色素痣,并以自体薄中厚皮片移植方法作对照,观察移植皮片成活率、创面愈合时间及瘢痕增生状况.结果 供皮区实验组创面愈合时间为（5.31±1.45）d,对照组为（11.63±1.69）d,两组比较差异有统计学意义（P＜0.05）,实验组瘢痕评分为1.62±0.38,对照组为6.38±0.58,两组比较差异有统计学意义（P＜0.05）;受皮区实验组皮肤移植成活率为（94.44±2.56）％,对照组为（95.13±3.13）％,移植皮片成活率于两组间差异无统计学意义,实验组瘢痕评分为5.38±0.62,对照组瘢痕评分为8.40±0.41,两组差异有统计学意义（P＜0.05）.结论 自体头皮与脱细胞异体真皮复合移植修复儿童巨大色素痣,对供区损伤小,移植区形态及功能良好,值得应用.     

构建生长因子缓释功能的复合型组织工程皮肤替代物

目的设计制备具有缓释表皮生长因子(EGF)功能的复合型组织工程皮肤替代物并进行相关性能检测。方法在组织工程脱细胞真皮的研究基础上,利用天然材料制备凝胶状类似表皮结构的生物膜作为覆盖,并加载表皮生长因子缓释系统,构建具有促表皮愈合功能的复合型组织工程皮肤替代物。并对此皮肤替代物的形态学、体外释放性能以及实际疗效做以考察。结果缓释EGF的复合型组织工程皮肤替代物具有良好的形态学性能,生物相容性好,EGF在体外的释放可达14d以上。动物实验表明实验组创面愈合率在术后各时间点均高于对照组(P<0.05);组织学观察显示愈合创面的表皮愈合程度明显优于对照组。结论具有EGF缓释功能的复合型组织工程皮肤替代物能有效促进猪全层皮肤缺损的创面愈合,可作为具有应用前景的覆盖材料进一步研究。     

“门轴样”瘢痕修薄皮瓣修复耳轮瘢痕疙瘩创面的应用

目的:“门轴样”瘢痕修薄皮瓣在耳轮瘢痕疙瘩切除后缺损修复的临床效果。方法:选取我科2018年8月至2021年12月耳轮瘢痕疙瘩14例，均采用“门轴样”瘢痕修薄皮瓣修复切除后创面，缝合后将切口线置于耳廓凸面，观察患者愈合情况及耳廓外形，评价其疗效。结果:术后14例患者皮瓣均成活，切口为Ⅰ期愈合。耳正面观未见切口线，切口线隐蔽，耳廓外形美观。未见继发缺损，耳廓未见变形。结论:“门轴样”瘢痕修薄皮瓣修复耳轮瘢痕疙瘩切口隐蔽，耳廓外形美观。     

一种增生性瘢痕动物模型的建立

目的建立一种兔耳瘢痕动物模型,观察兔耳腹侧创面在伤后不同时间瘢痕增生的情况。方法于38只新西兰兔的72只兔耳腹面手术切除2 cm×5 cm全层皮肤,创面用1%磺胺嘧啶银冷霜外敷包扎至愈合,换药隔日1次。未做手术的4只兔耳作对照。术后连续8个月观察兔耳创面自然愈合情况;用光镜观察兔耳创面瘢痕增生情况;分别用计算机图像分析系统和游标卡尺测量瘢痕胶原含量和瘢痕指数变化情况。结果兔耳创面上皮化后其色泽、厚度和质地均经历从瘢痕形成、成熟到退化的演变过程;1个月的瘢痕指数0.41±0.14,胶原含量30.69±12.39,分别较3-8个月为低(P<0.05),其变化与人体增生性瘢痕增生程度的消长趋势吻合。结论兔耳腹面全层皮肤缺损诱导的增生性瘢痕动物模型与人体增生性瘢痕相似,该模型可作为研究增生性瘢痕的发生机制及评估其治疗方法的较好的动物模型。     

磨削痂术治疗手部深Ⅱ度烧伤的临床疗效观察

目的:评价磨削痂术治疗手部深Ⅱ度烧伤的有效性和安全性。方法:应用削痂植皮疗法治疗烧伤患者手部深Ⅱ度创面90例、磨痂后覆盖异种脱细胞真皮基质疗法治疗82例、外用磺胺嘧啶银乳膏创面包扎89例。结果:削痂植皮术后14.1天创面愈合,治愈率97.8%,磨痂后覆盖异种脱细胞真皮基质术后13.5天创面愈合,治愈率100%。创面外用磺胺嘧啶银乳膏包扎,治愈率84.27%,创面愈合时间为26.2天。结论:早期采用磨痂后覆盖异种脱细胞真皮基质处理手部深Ⅱ度烧伤创面,手术创伤小,疗程短、治愈率高,功能恢复好。     

手术联合药物注射治疗耳部增生性瘢痕

目的探讨瘢痕部分手术切除,瘢痕残片内缓释药物注射及创面激光光凝综合治疗耳垂增生性瘢痕的临床效果。方法对56例耳垂增生性瘢痕患者采用手术切除大部分瘢痕,残留瘢痕内注射曲安奈德及利多卡因混悬液,创面激光光凝止血结痂。结果 56例耳垂增生性瘢痕患者术后创面愈合,随访1～2年49例未见瘢痕明显增生。结论外科手术联合药物综合治疗耳部增生性瘢痕方法简便,有效。     

预扩张斜方肌肌皮瓣在儿童面颈胸部烧伤后瘢痕修复中的应用

目的探讨预扩张技术联合斜方肌肌皮瓣修复儿童面颈胸部烧伤后瘢痕的手术可行性及效果。方法15例面颈胸部烧伤后瘢痕形成的患儿,在斜方肌部位设计供瓣区1～3个50-600ml容积的皮肤软组织扩张器,扩展预计容积,取出扩张器,以颈横动脉为血管蒂,比照瘢痕切除后所继发的创面及转移长度、扭转角度,切取斜方肌肌皮瓣修复创面,供瓣区直接拉拢缝合。结果14例手术成功,预期皮瓣大小（16．7±6．2）cm×（8．8±5．2）cm。1例术后皮瓣淤血后感染。供瓣区伤口愈合良好,成活皮瓣较瘢痕与邻近部位皮肤色泽、质地与缺损区组织更近似。结论预扩张斜方肌肌皮瓣适合于儿童面颈胸部烧伤后瘢痕的修复,术后效果理想。     

复方壳多糖真皮替代物体外抗菌作用的研究

目的 研究复方壳多糖真皮替代物对金黄色葡萄球菌、铜绿假单胞菌、大肠埃希菌、白念珠菌的体外抑菌作用。方法 制备复方壳多糖真皮替代物和复方胶原凝胶真皮,分别为实验组和对照组,各取50μL滴加在涂满细菌或真菌的平板,每种菌实验组和对照组样本各6个,孵育24h后观察抑菌环。结果 复方壳多糖真皮替代物对金黄色葡萄球菌、大肠埃希菌、铜绿假单胞菌具有抑菌作用,抑菌环均大于复方胶原凝胶真皮替代物,差异有统计学意义。两组对白念珠菌无抑菌作用。结论 复方壳多糖真皮替代物是有体外抗细菌作用的组织工程产品。     

SD大鼠组织工程皮肤构建及移植的实验研究

目的：构建SD大鼠全层组织工程皮肤,观察其在修复SD大鼠创面中的作用。方法：将分离、培养的SD乳鼠角质形成细胞和成纤维细胞种植于以牛I型胶原所构建的胶原海绵真皮支架两侧,构建出组织工程皮肤。分别观察自体皮肤、油纱布、组织工程皮肤覆盖SD大鼠皮肤缺损的愈合情况。第7、10、15d取创面皮肤标本行HE染色,组织工程皮肤再行纤维连接蛋白（fibronectin,FN）免疫组化染色。结果：构建的SD大鼠全层组织工程皮肤,移植于大鼠创面后,无出血、感染、坏死等不良反应,愈后良好。FN的表达呈现先升高后降低的规律性变化。结论：动物实验模型表明,以胶原海绵为真皮支架的组织工程皮肤是一种良好的皮肤替代物,可用于修复动物全层皮肤缺损。     

人羊膜上皮细胞复合去表皮的真皮构建组织工程皮肤修复裸鼠皮肤缺损的实验研究

目的 探索由人羊膜上皮细胞(hAEC)、成纤维细胞与去表皮的真皮(DED)构建组织工程皮肤修复裸鼠全层皮肤缺损的可行性.方法 采用低浓度胰蛋白酶多步消化分离法提取hAEC,并用两步酶消化法处理健康小儿包皮,获得成纤维细胞悬液,传代培养.将体外扩增培养至第3～5代的成纤维细胞和第2代hAEC分别接种在DED真皮面和基底膜面,体外器官培养构建组织工程皮肤.取3～4周龄健康雄性裸鼠20只,抽签法随机分为2组,在所有小鼠背部正中制备全层皮肤缺损模型.组织工程组用构建的组织工程全层皮肤覆盖创面;对照组创面仅覆盖凡士林油纱.分别于术后第7、14、21、28天对裸鼠全身及移植部位大体观察,比较两组间创面愈合时间及创面愈合率,并对移植部位行组织学观察.结果 hAEC具有干细胞特征,免疫荧光显示其表达结合转录因子4(0CT-4)、阶段特异性胚胎抗原4(SSEA-4).器官培养2周后,体外构建的组织工程皮肤形成4～9层复层表皮,且表皮的组织结构形态与正常皮肤类似.移植组织工程皮肤至裸鼠创面后肉眼观察显示,在移植后第7、14、21天,组织工程组创面愈合率分别为57.49％±6.11％、92.80％±3.10％、98.83％±0.25％,均明显高于对照组(22.93％±4.26％、54.57％±7.94％、91.16％±4.79％),差异均有统计学意义(n=10,t值分别为27.36、32.23、11.80,均P＜0.001),组织工程组创面愈合时间[(21.51±1.51)d]明显短于对照组[(28.80±1.14)d](n=10,￡=42.23,P＜0.001),且在移植后第28天移植物颜色与自体皮肤颜色接近.组织学观察显示,组织工程组上皮层次清晰,角化明显,真皮层细胞生长良好;对照组移植区上皮较薄且有部分缺损,真皮层次欠佳,且可见炎症细胞浸润.结论 用hAEC、成纤维细胞复合DED构建的组织工程皮肤移植后能在裸鼠体内存活,且创面愈合更佳,可望成为一种较理想的组织工程皮肤.     

A multiscale hybrid mathematical model of epidermal‐dermal interactions during skin wound healing

Following injury, skin activates a complex wound healing programme. While cellular and signalling mechanisms of wound repair have been extensively studied, the principles of epidermal‐dermal interactions and their effects on wound healing outcomes are only partially understood. To gain new insight into the effects of epidermal‐dermal interactions, we developed a multiscale, hybrid mathematical model of skin wound healing. The model takes into consideration interactions between epidermis and dermis across the basement membrane via diffusible signals, defined as activator and inhibitor. Simulations revealed that epidermal‐dermal interactions are critical for proper extracellular matrix deposition in the dermis, suggesting these signals may influence how wound scars form. Our model makes several theoretical predictions. First, basal levels of epidermal activator and inhibitor help to maintain dermis in a steady state, whereas their absence results in a raised, scar‐like dermal phenotype. Second, wound‐triggered increase in activator and inhibitor production by basal epidermal cells, coupled with fast re‐epithelialization kinetics, reduces dermal scar size. Third, high‐density fibrin clot leads to a raised, hypertrophic scar phenotype, whereas low‐density fibrin clot leads to a hypotrophic phenotype. Fourth, shallow wounds, compared to deep wounds, result in overall reduced scarring. Taken together, our model predicts the important role of signalling across dermal‐epidermal interface and the effect of fibrin clot density and wound geometry on scar formation. This hybrid modelling approach may be also applicable to other complex tissue systems, enabling the simulation of dynamic processes, otherwise computationally prohibitive with fully discrete models due to a large number of variables.     

Effects of Human Adipose-derived Stem Cells on Cutaneous Wound Healing in Nude Mice

Background

Despite numerous treatments available for deteriorated cutaneous wound healing such as a diabetic foot, there is still the need for more effective therapy. Adipose-derived stem cells (ASCs) are mesenchymal stem cells, which are self-renewing and multipotent. Mesenchymal stem cells have the potential for tissue repair and regeneration.

Objective

To investigate the effects of human ASCs on the healing of cutaneous wounds in nude mice.

Methods

15-mm round full-thickness skin defects were generated on the back of BALB/c nude mice. The mice were divided into three groups for wound coverage: (i) human ASCs-populated collagen gel, (ii) human dermal fibroblasts-populated collagen gel, and (iii) collagen gel alone. Wound contraction was prevented with a splint method. Wound size was measured 10 days after injury. At 28 days histological analysis was performed.

Results

Both ASCs and dermal fibroblasts accelerated wound closure, but dermal fibroblasts were more effective than ASCs. At 28 days, the dermal portion of ASCs or dermal fibroblasts wound scars were thicker than collagen gel wound scars.

Conclusion

ASCs and dermal fibroblasts stimulate cutaneous wound healing and improve scar thickness.     

Changes of human skin in subepidermal wound healing process

Background/purpose: The wound healing process involves unexplained mechanisms. An aberration in this process is known to cause dermal disorders such as keloid or hypertrophic scars, but the mechanism by which these scars are formed remains to be elucidated. Here we examined the usefulness of a non‐invasive optical imaging device to clarify mechanisms of wound healing and of scar formation. Methods: An 8 mm experimental wound was made in the forearms of six subjects by a suction blister method. To observe chronological changes associated with wound healing, horizontal cross‐sectional images were non‐invasively obtained of the wounded area from the skin surface down to 129 μm below at 21.5 μm intervals using in vivo laser confocal scanning microscopy (LCSM). Results: The wounds were covered with a new epidermis by week 2, at which time the dermal papilla count decreased while the thickness from the skin surface to the apex of the dermal papilla increased. The count and the thickness returned to the initial levels when the wound was healed. In two out of six subjects, fibrous tissues were observed in the upper dermis, whereas in one other subject, melanocyte‐like dendritic cells were observed in the epidermis–dermis border in later phases of wound healing. Conclusion: This non‐invasive method using in vivo LCSM revealed chronological changes in the dermis and epidermis during wound healing. In addition, although a scar was not formed in any of study subjects, this microscopy revealed aspects similar to the fibrous tissue overgrowth or to melanocyte migration, both of which may relate to wound healing. These results indicate the usefulness of this non‐invasive method in studies of wound healing and of scar formation.     

Microscopic inflammatory foci in burn scars: data from a porcine burn model

Background: Hypertrophic scars in burn victims usually occur after delayed wound healing and the active phase of scar formation can persist substantially even after wound closure. Currently, the pathophysiology of the hypertrophic scar is not completely understood. This study investigated the inflammatory response in scar tissue at week 6 post‐burn injury. Methods: A porcine deep dermal partial thickness burn model was used. At week 6 post‐burn, a total of 528 scar biopsies from 72 burn scars (7–8 biopsies from each scar) and 174 normal skin biopsies from 18 pigs were collected and examined histologically. Results: Microscopic inflammatory foci were identified in 17% (89/528) of scar biopsies. These microscopic inflammatory foci do not contain any irritant materials, are composed largely of polymorphonuclear cells with other inflammatory cells including multinucleate giant cells and show acute on chronic inflammatory response that has not been described previously in burn scars. Importantly, they are present in a significantly lower number in burns surgically debrided than in burns which have not been debrided. Conclusions: This study identifies microscopic inflammatory foci in the porcine scar tissue layer and recommends thorough cleaning/debriding of burned necrotic tissue in order to minimize the formation of these inflammatory foci in scar tissue. Wang X‐Q, Phillips GE, Wilkie I, Greer R, Kimble RM. Microscopic inflammatory foci in burn scars: data from a porcine burn model.     

Expression of prothrombin, thrombin and its receptors in human scars

The coagulation system is thought to play a pivotal role during the initial phase of wound healing, but mechanisms and cells involved are only partly understood. We have therefore examined human scars for the expression of thrombin, its precursor prothrombin and the thrombin receptors, thrombomodulin (TM) and protease-activated receptor-1 (PAR-1), compared with normal skin. Biopsies of scars were obtained from primary excision sites of melanoma patients (n = 20) and were compared with normal skin distant from the scar (n = 10), using immunohistochemistry. In addition, polymerase chain reaction analyses were performed on scar versus normal tissue and on cultured keratinocytes, fibroblasts and endothelial cells before and after stimulation with selected cytokines known to be active in wound healing. Normal epidermis was stained for prothrombin, thrombin, TM and PAR-1, and dermal tissue was stained only for TM and PAR-1. In scar tissue, thrombin and TM were upregulated in the epidermis and all four molecules in the dermis, independent of the age of the scars. In tissue extracts, mRNA expression of PAR-1 and prothrombin expression were, however, unchanged and TM even slightly decreased in scars, compared with normal skin. On analysis of cultured cells, keratinocytes expressed mRNA for PAR-1, TM and prothrombin, endothelial cells for PAR-1 and TM, and fibroblasts for PAR-1. An upregulation of PAR-1 mRNA was induced in fibroblasts on exposure to tumor necrosis factor-alpha (TNF-alpha), while it remained unchanged in endothelial cells in response to TNF-alpha. A downregulation of TM was induced in endothelial cells on exposure to TNF-alpha. These findings, showing a marked modulation of thrombin, PAR-1 and TM even in older human scar tissue, suggest that the coagulation system is not only involved during clotting, but also during the inflammatory and tissue remodelling phases of wound healing.     

Endothelial cell‐derived endothelin‐1 is involved in abnormal scar formation by dermal fibroblasts through RhoA/Rho‐kinase pathway

Hypertrophic scars and keloids are characterized by excessive dermal deposition of extracellular matrix due to fibroblast‐to‐myofibroblast differentiation. Endothelin‐1 (ET‐1) is primarily produced by vascular endothelial cells and plays multiple roles in the wound‐healing response and organ fibrogenesis. In this study, we investigated the pathophysiological significance of ET‐1 and involvement of RhoA, a member of the Rho GTPases, in hypertrophic scar/keloid formation. We found that ET‐1 expression on dermal microvascular endothelial cells (ECs) in hypertrophic scars and keloids was higher than that in normal skin and mature scars. We also confirmed that ET‐1 induced myofibroblast differentiation and collagen synthesis in cultured human dermal fibroblasts through the RhoA/Rho‐kinase pathway. Finally, since hypertrophic scar/keloid formation was most prominent in areas exposed to mechanical stretch, we examined how mechanical stretch affected ET‐1 secretion in human dermal microvascular ECs, and found that mechanical stretch increased ET‐1 gene expression and secretion from ECs. Taken together, these results suggest that dermal microvascular ECs release ET‐1 in response to mechanical stretch, and thereby contribute to the formation of hypertrophic scars and keloids through the RhoA/Rho‐kinase pathway.     

Comparison of the effectiveness of nonablative fractional laser versus ablative fractional laser in thyroidectomy scar prevention: A pilot study

A scar is a mark that remains after the healing of a wound or other morbid processes. In the past, treatment was mainly focused on severe scarring, such as the hypertrophic and burn scars. However, scars from relatively minor wounds can also be stressful. The site of an open thyroidectomy is the anterior neck, a prominently exposed part of the body, where postoperative scarring can cause patients distress. The cosmetic outcome of the scar after thyroidectomy is of particular importance to women, who constitute the majority of patients with thyroid disease. Active prevention is more likely to yield better cosmetic results and would require fewer treatment sessions and less expense than scar revision procedures. Many interventions have been proposed, but there is yet no universal consensus on optimal treatment. Recently, focus has been made on 'laser scar prevention', where various types of lasers have been used to improve the appearance of scars. The purpose of this study was to improve the appearance of scars, by laser intervention of the wound healing process. In this pilot study, we comparatively examined the effect of non-ablative 1550-nm fractional Er: glass laser and ablative 2940-nm fractional Er: YAG laser on fresh surgical scars of patients with Fitzpatrick skin type III-IV.     

Endothelial–mesenchymal transition as a novel mechanism for generating myofibroblasts during wound healing and scarring

Background

The endothelial–mesenchymal transition (EndMT) is an important mechanism in tissue regeneration and the development of organ fibrosis. Whether EndMT occurs in wound healing and scarring remains unknown.

Materials and Methods

The isolated cells from the normal dermal tissue and the wound tissue of mouse with full-thickness skin wound, and human scar tissue sections were performed with CD31/factorVII and α-SMA immunohistochemical staining and H and E staining. The ratio of factor VII or CD31/α-SMA double-positive cells in factor VII-positive cells was assessed in the isolated cells and in scar tissues.

Results

In this study, we found that approximately 27–60% of ECs coexpressed VII factor and α-SMA in the isolated cells from the wound tissues of mice, which was significantly higher than that of normal dermal tissue cells. Accordingly, the number of CD31/α-SMA double-positive cells in mouse wound tissue sections was also significantly more than that in normal dermal tissue sections. In scar tissues, in addition to high-density microvessels, a large number of proliferative ECs in scar strama and CD31/α-SMA double-positive cells were also found. Approximately 46.82 to 84.11% of ECs and 68.77 to 95.25% of myofibroblasts coexpressed VII factor and α-SMA, and these two values in hypertrophic scars were significantly higher than those in keloids.

Conclusion

These results confirmed that ECs might contribute to the emergence of myofibroblasts in the wound and scar tissue via the process of EndMT.