Schwann cells contribute to keloid formation

Keloids are disfiguring, hypertrophic scars with yet poorly understood pathomechanisms, which could lead to severe functional impairments. Here we analyzed the characteristics of keloidal cells by single cell sequencing and discovered the presence of an abundant population of Schwann cells that persisted in the hypertrophic scar tissue after wound healing. In contrast to normal skin, keloidal Schwann cells possess a repair-like phenotype and high cellular plasticity. Our data support the hypothesis that keloidal Schwann cells contribute to the formation of the extracellular matrix and are able to affect M2 polarization of macrophages. Indeed, we show that macrophages in keloids predominantly display a M2 polarization and produce factors that inhibit Schwann cell differentiation. Our data suggest a contribution of this cross-talk to the continuous expansion of keloids, and that targeting Schwann cells might represent an interesting novel treatment option for keloids.

Inhibitory Effect of the LY2109761 on the Development of Human Keloid Fibroblasts

Keloids are scars characterized by abnormal proliferation of fibroblasts and overproduction of extracellular matrix components including collagen. We previously showed that LY2109761, a transforming growth factor- (TGF-) β receptor inhibitor, suppressed the secretion of matrix components and slowed the proliferation of fibroblasts derived from human hypertrophic scar tissue. However, the exact mechanism underlying this effect remains unclear. Here, we replicated the above results in keloid-derived fibroblasts and show that LY2109761 promoted apoptosis, decreased the phosphorylation of Smad2 and Smad3, and suppressed TGF-β1. These results suggest that the development and pathogenesis of keloids are positively regulated by the Smad2/3 signaling pathway and the upregulation of TGF-β1 receptors. LY2109761 and other inhibitors of these processes may therefore serve as therapeutic targets to limit excessive scarring after injury.

Objective Assessment Tools: Physical Parameters in Scar Assessment

Objective assessment tools can be used to evaluate whether (new) scar treatment is effective and to monitor the scar’s response to interventions in clinical practice. It is important to take the clinimetric properties of each tool into account, especially when used for the follow-up of an individual patient. An overview is provided for three important physical scar parameters that can be assessed by noninvasive objective tools: color, elasticity, and perfusion. To assess the color of a scar, an array of tools is available, all using reflectance spectroscopy and determining color by measuring the intensity of reflected light of specific wavelengths. The handheld DSM III ColorMeter offers read-out of erythema and melanin index values as well as CIEL∗a∗b values. The interrater reliability is best for the parameter a∗ of the DSM III ColorMeter. To assess scar elasticity, the Cutometer is the most widely used tool. Scar deformation is measured using negative pressure and reflected in relative and absolute elasticity parameters. On the contrary, firmness or hardness of scar tissue can be quantified by tonometry, a technique that works by exerting pressure on the skin. Lastly, it is of interest to measure scar blood flow (i.e., perfusion) as several treatment regimens work by destructing the microvasculature and/or reducing the blood flow to enhance shrinkage of hypertrophic scar tissue. Laser Doppler imaging and laser speckle imaging can be used to quantify and visualize scar blood flow, but a thorough clinimetric evaluation of these tools in scars is not performed yet.

Clinical and morphological characteristics of the vascular bed of hypertrophic scar tissue in different periods of its formation

Background. The state of the microcirculatory bed in the scar tissue is extremely important for determining the most appropriate methods of conservative and surgical treatments. Only few studies have assessed the vascular features of scar tissue. The objective was to study and analyze the morphological features of the vascular bed of scar tissue and their clinical implications. Materials and methods. Fifty-four patients with hypertrophic post-burn scars were examined. The study used a clinical method and performed histological analysis of the scars biopsy specimens, including a survey light microscopy, a morphometric assessment of the vascular bed as well as the verification of the collagen fibers of scar tissue with an immunohistochemical (IHC) analysis with specific monoclonal antibodies (AT) (Novocastra, Bond) to Type I and III collagens. Results. A significant increase in the total area of the vessels of the rumen in the first 6 months of its formation was observed in comparison with intact skin and later maturation of the scar tissue (in % in 1 mm2 of intact skin – 8.50, in the rumen in terms of up to 6 months – 13.10). The average number of vessels in the scar tissue and the total area of their lumen in the maturing rumen from 2 to 5 years decreased in comparison with that in the intact skin. The nodes were detected in the scars by an early appearance of the clinical signs of vascular disorders including blisters and erosions on thickened and hyperemic scar tissues. Discussion. In the developing hypertrophic rumen, the circulatory conditions gradually deteriorated due to the compression and obliteration of the vessels of the skin with collagen. The enhancement in perfusion recorded using laser Doppler fluorometry may be associated with a significant dilatation of the rumen vessels, rather than because of actual enhanced perfusion. Conclusions. 1. The increase in the vascular cross sectional area in the early stages of scar formation is attributable to the expansion of their lumen vessels. In the ripened rumen, the number of vessels is 3 times less than that in intact skin. 2. Hyperemia of the hypertrophic scar is caused by a substantial widening of the vessels of the scar tissue, and not by an increase in their number. 3. The use of a hypertrophic scar for the creation of rotational and other flaps is associated with a high risk of trophic complications.

FACTORS INFLUENCING THE OCCURRENCE OF HYPERTROPHIC SCARS AMONG POSTOPERATIVE PATIENTS IN GARUT, INDONESIA

Background: Hypertrophic scar causes physical and psychological problems. Thus understanding the factors related to the occurrence of hypertrophic scar tissue is needed. Little is known about its influencing factors in Indonesia, especially in Garut.Objective: This study aims to examine the relationships between hypertrophic scar and its influencing factors, and identify the most dominant factor of the occurrence of hypertrophic scars.Methods: This was an observational case control study using retrospective approach in Polyclinic of Surgery of Regional Public Hospital of dr. Slamet of Garut Regency. There were 40 samples recruited in this study by purposive sampling, which was divided to be case group (20 patients) and control group (20 patients). Data were collected using Stony Brook Scar Evaluation Scale by observation and documentation of the medical records of patients. Data were analyzed using logistic regression analysisResults: Findings indicated that there were significant relationships between the surgical wound infection (p = 0.02), family history (p = 0.026), and type of suture (p = 0.043) with the occurrence of hypertrophic scars. The most dominant factor on the occurrence of hypertrophic scars was type of suture, acid polyglactin 910. The variables that had no significant relationships with the occurrence of hypertrophic scar tissue were age (p = 0.34), area of surgical wound (p = 0.177), and smoking habit (p = 0.479).Conclusion: There were significant relationships between infection of surgical wound, genetic history, the type of suture, and the occurrence of hypertrophic scar tissue. The most dominant factor that influenced the occurrence of hypertrophic scar tissue was the type of suture. Therefore, it is suggested to health professionals to modify the using of acid polyglactin 910 sutures, and nurses particularly need to provide the information regarding the family history and genetic-related hypertrophic scar, and prevent the infection of surgical wound after operation.