Laser-Assisted Skin Healing (LASH) in hypertrophic scar revision

Abstract

Laser-Assisted Skin Healing (LASH) is based on the therapeutic effects of controlled thermal post-conditioning. The authors have previously demonstrated on humans that an 810-nm diode-laser system could assist wound closure leading to an improvement of wound healing with a resulting indiscernible scar. A 47-year-old woman (skin type II), who developed systematically hypertrophic scars after surgery, was enrolled for a hypertrophic scar revision. Excess scar tissue was removed. Immediately after the conventional closure of the incision, laser irradiation (120 J/cm²) using a 0.8 cm² spot size (rectangular spot, length = 20 mm, width = 4 mm) was applied. Topical silicone gel sheeting (Cerederm®) was applied for 2 months afterwards to prevent a thick scar from reforming. No complications occurred during the course of this study. No recurrence of hypertrophic scarring was noticed 6 months after scar revision. This study reports, for the first time, the possibility of improving the appearance of hypertrophic scarring in scar revision by altering through thermal stress the wound-healing process. Since the appropriate initial management of wounds is of importance, the LASH technique could be offered as a new approach to prevent hypertrophic scarring.     

Efficacy of low-level laser therapy on scar tissue

Abstract

Background: Physiotherapy has a very important role in the maintenance of the integumentary system integrity. There is very few evidence in humans. Nevertheless, there are some studies about tissue regeneration using low-level laser therapy (LLLT). Aim: To analyze the effectiveness of LLLT on scar tissue. Methods: Seventeen volunteers were stratified by age of their scars, and then randomly assigned to an experimental group (EG) — n = 9 – and a placebo group (PG) – n = 8. Fifteen sessions were conducted to both the groups thrice a week. However, in the PG, the laser device was switched off. Scars’ thickness, length, width, macroscopic aspect, pain threshold, pain perception, and itching were measured. Results: After 5 weeks, there were no statistically significant differences in any variable between both the groups. However, analyzing independently each group, EG showed a significant improvement in macroscopic aspect (p = 0.003) using LLLT. Taking into account the scars’ age, LLLT showed a tendency to decrease older scars’ thickness in EG. Conclusion: The intervention with LLLT appears to have a positive effect on the macroscopic scars’ appearance, and on old scars’ thickness, in the studied sample. However, it cannot be said for sure that LLLT has influence on scar tissue.     

Integrin expression in the dermis during scar formation in humans

To evaluate changes leading to human wound reorganization we examined by immunohistochemistry the expression of several extracellular matrix (ECM) receptors (alpha2 chain of VLA-2, alpha3 chain of VLA-3, alpha6 chain of VLA-6, alphav, and beta1/beta3 chains of integrins) in a series of biopsies of human skin wounds healing by primary intention. The first time point investigated in this study was day 6 after injury, i.e. when a fibrin clot has been almost completely replaced by the granulation tissue. Gradual changes in integrin expression in granulation tissue and in the dermal scar were observed from the first time point investigated and were characterized by an up-regulation of alpha2beta1 complex, alphav integrin subunit, and beta1 integrin subunit. At day 27, the expression of the alpha2 chain of VLA-2 in the scar decreased. The expression of alphav and beta1 integrin subunits decreased but was still detectable by day 35. Vitronectin expression from day 7 onwards was also increased and colocalized to the area of the wounded dermis, and decreased by day 27. Our data suggests that, during the remodelling of the provisional matrix of the wound, dermal fibroblasts express transiently mainly alpha2 and alphav subunits of integrins associated with up-regulation of the beta1 subunit. It seems that up-regulation of some chains of integrins may be involved in the control of deposition of ECM components associated with wound healing.     

强功率UVA1照射对增生性瘢痕动物模型瘢痕形成的影响

目的 探讨不同剂量UVA1对全层皮肤缺损诱导的兔耳增生性瘢痕模型的影响情况。方法18只新西兰白兔双耳腹面手术切除2 cm × 5 cm全层皮肤至筋膜,建立兔耳增生性瘢痕模型后,随机分成3组,每组6只兔,将每只兔左耳分别于伤后即刻、1个月、2个月开始用不同剂量大功率UVA1照射,右耳为非照射组。各照射组又分为两个剂量照射组,兔耳分别每次照射UVA1 60 J/cm2、110 J/cm2,连续30次。结果 创伤建模1个月、2个月后开始照射UVA1组,与照射前比较,高剂量组照射后瘢痕处真表皮厚度（282.32 ± 58.60;336.50 ± 98.34）和真皮胶原含量（24.91 ± 16.88;34.47 ± 8.90）均显著降低（P < 0.05）;照射组与非照射组在UVA1照射前后差值的比较,高剂量组照射后瘢痕处表真皮厚度差值（-143.52 ± 42.91;-142.44 ± 49.96）和真皮胶原含量差值（-56.39 ± 15.04;-48.35 ± 10.44）的差异有统计学意义（P < 0.05）;各照射组UVA1对瘢痕皮肤厚度（811.68 ± 79.03;659.08 ± 178.98）和胶原含量（67.80 ± 9.06;61.35 ± 12.91）的影响均存在剂量依赖性（P < 0.05）。而创伤建模的同时照射UVA1组,两种剂量的UVA1照射后瘢痕处皮肤厚度和胶原含量较非照射耳均显著增加（P < 0.05）。结论 上皮化后开始UVA1照射可使瘢痕变软,皮肤变薄,胶原含量降低。创伤同时照射UVA1不仅不能阻止瘢痕模型的建立,反而加重瘢痕。     

外用透明质酸在皮肤科的应用

透明质酸（HA）是一种存在于人体基质内的多聚糖, 临床应用广泛,HA具有较高的生物相容性,增加了药物在皮损部位的停留时间;HA具有组织修复作用,缩短了伤口的愈合时间;HA对皮肤的屏障修复和炎症的调节也有一定作用。本文对HA的理化性质、生物性质和外用透明质酸在皮肤科的临床应用进行综述。     

The macrophage-activating lipopeptide-2 accelerates wound healing in diabetic mice

Wound healing in healthy individuals proceeds at an optimal rate. However, in patients, with -- e.g.-- locally impaired blood flow or diabetes, chronic wounds develop and often become infected. Chronic wounds mean a low quality of life for the afflicted patients, not to mention enormous costs. Rather than using recombinant growth factors to accelerate wound healing, we employed the toll-like receptor agonist macrophage-activating lipopeptide-2 (MALP-2) to improve the healing of full-thickness excision skin wounds in an animal model with obese, diabetic mice. A gene array experiment suggested that MALP-2 stimulates the release of various mediators involved in wound healing. Further data to be presented in this study will show (i) that MALP-2 is capable of stimulating the appearance of the monocyte chemoattractant protein-1 at the wound site, (ii) that this leads to increased leucocyte and, in particular, macrophage infiltration and (iii) that MALP-2-treated wounds closed 2 weeks earlier than vehicle-treated controls. MALP-2, thus, appears to stimulate the early inflammatory process needed to set in motion the ensuing consecutive natural steps of wound healing resulting in wound closure.     

Regeneration of rete ridges in Lanyu pig (Sus scrofa): Insights for human skin wound healing

Rete ridges are important to the mechanical function of skin in animals with minimal hair, including humans. As mice do not exhibit rete ridges, the need for a quality animal model is pertinent. Here, we develop a Lanyu pig (Sus scrofa) full‐thickness wound model to explore tissue regeneration because the architecture and function are similar to humans and inbred genetic variants are available. Full‐ and partial‐thickness wounds were generated on the dorsum. Full‐thickness wounds at post‐wound day 57 exhibit severe scar with no signs of wound‐induced hair follicle neogenesis. Wound contraction is greater in the anterior/posterior relative to the medial/lateral axis. In wound beds, K14⁺ cells increased while K10⁺, p63⁺ and PCNA⁺ cells decreased compared to unwounded tissue. Epithelial β‐catenin is unchanged. The wound bed expresses more ColI, less ColIII and no elastin. Rete ridges do not form after full‐thickness wounding, but incompletely regenerate after partial‐thickness wounding. An alkaline phosphatase (ALP)⁺ cell population, not associated with hair follicles, is present at the bottom of the rete ridge basal layer in pig and human unwounded skin. These K5⁺/K10^?/PCNA^?/ALP⁺ epithelial cells are absent after full‐thickness wounding but reappear after partial‐thickness wounding, before invagination of new rete ridges. In summary, full‐thickness wounding on the dorsum of Lanyu pigs results in scar formation and perturbed molecular expression while partial‐thickness wounding permits limited rete ridge and papillary dermis regeneration. Future functional studies and further characterization will help contribute knowledge for the regenerative medicine field.     

Laminin 10/11: an alternative adhesive ligand for epidermal keratinocytes with a functional role in promoting proliferation and migration

We have investigated the expression and function of the isoforms of laminin bearing the alpha5 chain, i.e. laminin-10/11 in neonatal and adult human skin. By immunostaining human skin derived from a variety of anatomic sites, we found that the laminin-alpha5 chain is expressed abundantly in the basement membrane underlying the interfollicular epidermis and the blood vessels in the dermis. Interestingly, while the expression level of the well-studied laminin-5 isoform did not change significantly with age, laminin-10/11 (alpha5 chain) appeared to decrease in the basement membrane underlying the epidermis, in adult skin. In contrast, the levels of laminin-10/11 in the basement membrane underlying blood vessels remained unchanged in neonatal vs. adult skin. Importantly, in vitro cell adhesion assays demonstrated that laminin-10/11 is a potent adhesive substrate for both neonatal and adult keratinocytes and that this adhesion is mediated by the alpha3beta1 and alpha6beta4 integrins. Adhesion assays performed with fractionated basal keratinocytes showed that stem cells, transit amplifying cells and early differentiating cells all adhere to purified laminin-10/11 via these receptors. Further, laminin-10/11 provided a proliferative signal for neonatal foreskin keratinocytes, adult breast skin keratinocytes, and even a human papillomavirus type-18 transformed tumorigenic keratinocyte cell line in vitro. Finally, laminin-10/11 was shown to stimulate keratinocyte migration in an in vitro wound healing assay. These results provide strong evidence for a functional role for laminin-10/11 in epidermal proliferation during homeostasis, wound healing and neoplasia.     

增生性瘢痕发生和演变过程中成纤维细胞生物学功能变化及其意义

目的 探索增生性瘢痕在发生和演变过程中,成纤维细胞生物学功能变化的规律及其意义.方法 选取人不同时期增生性瘢痕组织和正常皮肤组织,进行HE染色观察.另外,分离和培养不同时期瘢痕和正常皮肤中成纤维细胞,RT-PCR分别检测成纤维细胞在转移生长因子（TGF-β1）、血管内皮细胞生长因子（VEGF）、和Ⅰ、Ⅲ胶原mRNA表达水平的变化.结果 HE染色可见正常皮肤细胞和微血管数目较少,早期瘢痕增多,炎症细胞浸润明显.增生期瘢痕成纤维细胞和微血管增多.随病情进展,微血管呈缩窄倾向.消退期瘢痕成纤维细胞减少,微血管狭窄或闭塞.成熟期瘢痕见微血管、成纤维细胞数目进一步减少,微血管管腔小,大部分开放.RT-PCR检测结果发现,正常皮肤来源的成纤维细胞TGF-β1、VEGF和Ⅰ、Ⅲ胶原mRNA有较低表达,早期瘢痕成纤维细胞TGF-β1、VEGF和Ⅰ、Ⅲ胶原mRNA表达水平开始升高,在增生期表达到达高峰,消退期瘢痕的表达开始下降,到成熟期表达最低.结论 增生性瘢痕发生和演变过程中,成纤维细胞功能存在动态改变,这种动态改变与瘢痕的发生和消退成熟的病理变化相关.     

Complete skin regeneration with medical honey after skin loss on the entire circumference of a leg in a cat

Second-intention healing of wounds on distal extremities in cats can be considered for superficial wounds involving less than 30% of the circumference of the limb. In our case the wound was characterized by complete loss of skin on 100% of the circumference of the limb from the elbow to the paw with contemporary ulnar fracture. Advanced reconstructive surgery or amputation of the leg was not acceptable for the owner; therefore, healing with medical honey was selected. In 49 days, an 80% reduction of the wound was observed. The wound healed completely by second intention with regrowth of hair and minimal scarring. Complete function was restored in the affected leg. To the authors’ knowledge, this is the first written report of such extensive complete loss of skin on a leg in a cat healed by second intention with the use of medical honey.     

Calmodulin 4 is dispensable for epidermal barrier formation and wound healing in mice

Calcium‐mediated signals play important roles in epidermal barrier formation, skin homoeostasis and wound repair. Calmodulin 4 (Calm4) is a small, Ca²⁺‐binding protein with strong expression in suprabasal keratinocytes. In mice, Calm4 first appears in the skin at the time of barrier formation, and its expression increases in response to epidermal barrier challenges. In this study, we report the generation of Calm4 knockout mice and provide evidence that Calm4 is dispensable for epidermal barrier formation, maintenance and repair.     

Novel insights into the role of S100A8/A9 in skin biology

S100A8 and S100A9 belong to the damage‐associated molecular pattern molecules. They are upregulated in a number of inflammatory skin disorders. Owing to their abundance in myeloid cells, the main function of S100A8/A9 has been attributed to their role in inflammatory cells. However, it is becoming increasingly clear that they also exert important roles in epithelial cells. In this review, we discuss the context‐dependent function of S100A8/A9 in epithelial cells and their impact on wound healing, psoriasis and other skin diseases.     

强功率UVA1对兔耳增生性瘢痕模型影响的机制研究

目的 探讨不同剂量UVA1对全层皮肤缺损诱导的兔耳增生性瘢痕模型的影响的可能机制。方法 24只新西兰白兔双耳腹面手术切除2 cm × 5 cm全层皮肤至筋膜建立兔耳增生性瘢痕模型后,随机分成4组,每组6只,将每只兔左耳分别于伤后即刻（U0）、1个月（U1）、2个月（U2）、3个月（U3）开始强功率UVA1照射,右耳为非照射组;各照射组分为两个剂量组［60 J/cm2（M）,110 J/cm2（H）］,分别在照射前后进行MMP-1、TIMP-1、TGF-β1、PCNA和α-SMA的免疫组织化学染色和透射电镜检查。结果 与照射前比较,中高剂量组照射后瘢痕处MMP-1表达：U1组分别为10.43 ± 1.61、11.16 ± 1.57;U2组分别为8.63 ± 2.61、7.33 ± 1.58;U3组分别为5.74 ± 1.43、3.11 ± 0.27;均显著增加（P < 0.05）。TGF-β1表达：U1组分别为12.51 ± 4.13、12.02 ± 5.02;U2组分别为18.74 ± 6.42、19.69 ± 4.52;U3组分别为20.51 ± 1.78、29.45 ± 6.55。PCNA表达：U1组分别为2.67 ± 0.44、2.04 ± 0.65;U2组分别为4.50 ± 0.97、5.82 ± 0.68;U3组分别为7.45 ± 1.47、8.16 ± 1.07;均显著降低（P < 0.05）。只有高剂量组显著降低TIMP-1表达,U1组为12.74 ± 4.58,U2组为15.17 ± 3.26,U3组为20.72 ± 3.31（P < 0.05）。只有U1H、U1M、U2H组α-SMA表达（1.33 ± 0.34、2.04 ± 0.20、3.60 ± 1.75）显著降低（P < 0.05）。U0组：与对照组比较,高剂量组MMP-1表达（2.25 ± 0.38）显著降低（P < 0.05）,而TGF-β1表达（23.90 ± 2.92）显著增加（P < 0.05）。中、高剂量组PCNA（7.42 ± 0.65、7.59 ± 0.31）、TIMP-1（29.82 ± 1.94、33.51 ± 1.19）及α-SMA表达（6.31 ± 0.61、2.97 ± 0.56）均显著增加（P < 0.05）。透射电镜结果显示：强功率UVA1照射后胶原纤维直径变细;成纤维细胞胞质变少,细胞器欠发达,多数为静止的纤维细胞。结论 UVA1对瘢痕的作用可能与其抑制TGF-β1、TIMP-1、PCNA和α-SMA的表达,同时促进MMP-1的表达,从而促进基质蛋白降解及抑制成纤维细胞和肌成纤维细胞的增值活性有关。如果UVA1过早干预,则会出现相反的结果。     

Possible pro‐inflammatory role of heparin‐binding epidermal growth factor‐like growth factor in the active phase of systemic sclerosis

Heparin‐binding epidermal growth factor (EGF)‐like growth factor (HB‐EGF) is a member of the EGF family growth factors, which affects multiple aspects of the wound healing process such as epithelialization, wound contraction and angiogenesis. In our study, we measured the serum HB‐EGF levels of 51 systemic sclerosis (SSc) patients, which showed a significant increase compared with those of 20 normal subjects. Further analysis revealed a positive correlation between the HB‐EGF level and pulmonary ground‐glass score but no correlation between the former and pulmonary fibrosis score. Other findings include: a significant increase of serum sialylated carbohydrate antigen KL‐6 levels and significant shortness of disease duration in the diffuse cutaneous SSc patients with elevated HB‐EGF levels; and significantly higher HB‐EGF levels in the presence of Raynaud's phenomenon, in that of telangiectasia, and in the absence of contracture of phalanges in all SSc patients. We then evaluated HB‐EGF mRNA levels of fibroblasts harvested from skin samples of the SSc patients and those of foreskin‐derived fibroblasts treated with transforming growth factor‐β, both of which were significantly higher than each control. In conclusion, we speculate that HB‐EGF plays a pro‐inflammatory role in the active skin and lung lesions of SSc.     

多磺酸黏多糖乳膏对兔耳增生性瘢痕的抑制作用及机制研究

【摘要】 目的 探究多磺酸黏多糖乳膏对增生性瘢痕形成的抑制作用及机制。方法 在新西兰白兔（16只）双耳建立直径6 mm的圆形全层创面,构建兔耳增生性瘢痕模型,每只兔耳3个瘢痕创面,左耳瘢痕作为多磺酸黏多糖乳膏实验组,右耳瘢痕为基质对照组,分别外涂多磺酸黏多糖乳膏和基质乳膏,1只兔耳用药量约0.4 g,2次/d,连续6周。分别在用药开始第0天（手术14 d）、14天（手术后28 d）和42天（手术后56 d）取瘢痕组织进行HE染色、Masson染色和免疫组化实验,评估组织病理评分,检测瘢痕厚度、胶原纤维密度和Ⅰ、Ⅲ型胶原蛋白表达及Ⅰ/Ⅲ型胶原蛋白比值。采用t检验和单因素方差分析比较两组各指标差异。结果 HE染色结果显示,与给药前相比,给药42 d对照组存在大量细胞外基质沉积、炎症细胞浸润和局部充血等,而实验组未见明显改变 。给药0、14、42 d,对照组兔耳瘢痕组织病理结构评分明显升高,分别为4.16 ± 1.61、6.50 ± 1.46、6.53 ± 1.34（F = 13.69,P = 0.001）,而实验组无明显变化（4.65 ± 1.52、5.13 ± 1.83、5.38 ± 1.60;F = 0.78,P > 0.05）。Masson染色结果显示,给药42 d对照组胶原纤维含量极高,被染成深蓝色,而实验组胶原纤维含量有所下降 ;随着给药时间的增加,与给药前相比,对照组瘢痕组织厚度明显增加（F = 5.64,P = 0.007）,而实验组无明显变化（F = 1.48,P > 0.05）。免疫组化结果显示,与给药0 d相比,实验组和对照组各时点Ⅲ型胶原蛋白表达均无明显改变（F = 0.22、0.92,均P > 0.05）,但对照组Ⅰ型胶原蛋白表达和Ⅰ/Ⅲ型胶原蛋白比例明显上升（F = 7.47,P < 0.001;F = 4.70,P = 0.005）;给药42 d,与对照组相比,实验组Ⅰ型胶原蛋白表达和Ⅰ/Ⅲ型胶原蛋白比值明显下降（t = 3.04,P = 0.007;t = 2.35,P = 0.030） 。结论 多磺酸黏多糖乳膏局部应用可有效降低瘢痕厚度和抑制胶原纤维增生以及Ⅰ型胶原蛋白表达,预防和抑制瘢痕增生。