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Keloids are locally aggressive scars that typically invade into healthy surrounding skin and cause both physical and psychosocial distress to the patient. These pathological scars occur following minimal skin trauma after a variety of causes including burns and trauma. Although the pathogenesis of keloid disease is not well understood, it is considered to be the end product of an abnormal healing process. The aim of this review was to investigate the molecular and cellular pathobiology of keloid disease in relation to the normal wound healing process. The molecular aberrances in keloids that correlate with the molecular mechanisms in normal wound healing can be categorized into three groups: (1) extracellular matrix proteins and their degradation, (2) cytokines and growth factors, and (3) apoptotic pathways. With respect to cellular involvements, fibroblasts are the most well-studied cell population. However, it is unclear whether the fibroblast is the causative cell; they are modulated by other cell populations in wound repair, such as keratinocytes and macrophages. This review presents a detailed account of individual phases of the healing process and how they may potentially be implicated in aberrant raised scar formation, which may help in clarifying the mechanisms involved in keloid disease pathogenesis.

Abstract:The skin offers a perfect model system for studying the wound healing cascade, which involves a finely tuned interplay between several cell types, pathways and processes. The dysregulation of these factors may lead to wound healing disorders resulting in chronic wounds, as well as abnormal scars such as hypertrophic and keloid scars. As the contribution of stem cells towards tissue regeneration and wound healing is increasingly appreciated, a rising number of stem cell therapies for cutaneous wounds are currently under development, encouraged by emerging preliminary findings in both animal models and human studies. However, we still lack an in-depth understanding of the underlying mechanisms through which stem cells contribute to cutaneous wound healing. The aim of this review is, therefore, to present a critical synthesis of our current understanding of the role of stem cells in normal cutaneous wound healing. In addition to summarizing wound healing principles and related key molecular and cellular players, we discuss the potential participation of different cutaneous stem cell populations in wound healing, and list corresponding stem cells markers. In summary, this review delineates current strategies, future applications, and limitations of stem cell-based or stem cell-targeted therapy in the management of acute and chronic skin wounds.

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Our data show that cells from the growing margin of keloid scars have a higher production of collagen I and III compared with other lesional sites. Additionally, temporal extension of cell passage affects collagen production. Clinically these findings may influence selection and interpretation of extended cell passage and provide future direction for lesional site-specific therapy in keloid scars.

Striae distensae are an extremely common, therapeutically challenging form of dermal scarring. Risk factors have been reported but much remains to be understood about their epidemiology, diagnosis and treatment. Up-to-date knowledge of the scientific research and the evidence behind both preventative and therapeutic agents are vital in order to understand striae and to offer patients the best therapeutic alternatives. We present a clinical review of the current literature concerning striae distensae and their prevention and treatment. A systematic review of the literature was undertaken using Medline, Embase and Google Scholar. Articles in English, Spanish, Portuguese, Turkish and French were included. Striae distensae occur in pregnancy, puberty and obesity as well as in numerous medical conditions and following therapeutic interventions. Proposed aetiological mechanisms relate to hormones, physical stretch and structural alterations to the integument. Assessment methods include subjective visual scoring and various imaging modalities. Treatments that we have evaluated include topical agents, used prophylactically or therapeutically, as well as light and laser therapies, which have shown improvements in the appearance of striae. Few high level evidence based medicine randomized controlled trials evaluating treatments for striae distensae exist. Topical therapeutic agents appear to lack efficacy in the prevention of striae distensae.

Dupuytren disease (DD) is a fibroproliferative disorder of unknown etiology that often results in shortening and thickening of the palmar fascia, leading to permanent and irreversible flexion contracture of the digits. This Review provides a detailed update of the scientific understanding of DD and its clinical management, with perspectives on emerging research and therapy. Established risk factors include genetic predisposition and ethnicity, as well as sex and age. Several environmental risk factors (some considered controversial) include smoking, alcohol intake, trauma, diabetes, epilepsy and use of anticonvulsant drugs, and exposure to vibration. DD has been variously attributed to the presence of oxygen free radicals, trauma to the palmar fascia, or aberrant immune responses with altered antigen presentation, or to interactions between these proposed mechanisms. The presence of immune cells and related phenomena in DD-affected tissue suggests that DD is possibly immune-related. Mechanically, digital contracture is caused by myofibroblasts in the DD palmar fascia; however, the exact origin of this cell type remains unknown. The mainstay of treatment is surgical release or excision of the affected palmodigital tissue, but symptoms often recur. Nonsurgical correction of DD contractures can be achieved by Clostridium histolyticum collagenase injection, although the long-term safety and recurrence rate of this procedure requires further assessment.