Keloid scar, dermal benign fibro-proliferative growth that extends outside the original wound and invades adjacent dermal tissue due to extensive production of extracellular matrix, especially collagen, which caused by over expression of cytokines and growth factors. Although many attempts were made to understand the exact pathophysiology and the molecular abnormalities, the pathogenesis of keloid scar is yet to be determined. Even though there are several treatment options for keloid scars include combination of medical and surgical therapies like combination of surgical removal followed by cryotherapy or intralesional steroid therapy, the reoccurrence rate is still high despite the present treatment. In this review, PubMed, clinical key and Wright State Library web site have been used to investigate any update regarding Keloid disease. We used Keloid, scar formation, hypertrophic scar and collagen as key words. More than 40 articles have been reviewed. This paper reviews literature about keloid scar formation mechanism, the most recent therapeutic options including the ones under research.
Collagen, which is produced by fibroblasts, is the most abundant protein in the human body. A natural structural protein, collagen is involved in all 3 phases of the wound-healing cascade. It stimulates cellular migration and contributes to new tissue development. Because of their chemotactic properties on wound fibroblasts, collagen dressings encourage the deposition and organization of newly formed collagen, creating an environment that fosters healing. Collagen-based biomaterials stimulate and recruit specific cells, such as macrophages and fibroblasts, along the healing cascade to enhance and influence wound healing. These biomaterials can provide moisture or absorption, depending on the delivery system. Collagen dressings are easy to apply and remove and are conformable. Collagen dressings are usually formulated with bovine, avian, or porcine collagen. Oxidized regenerated cellulose, a plant-based material, has been combined with collagen to produce a dressing capable of binding to and protecting growth factors by binding and inactivating matrix metalloproteinases in the wound environment. The increased understanding of the biochemical processes involved in chronic wound healing allows the design of wound care products aimed at correcting imbalances in the wound microenvironment. Traditional advanced wound care products tend to address the wound's macroenvironment, including moist wound environment control, fluid management, and controlled transpiration of wound fluids. The newer class of biomaterials and wound-healing agents, such as collagen and growth factors, targets specific defects in the chronic wound environment. In vitro laboratory data point to the possibility that these agents benefit the wound healing process at a biochemical level. Considerable evidence has indicated that collagen-based dressings may be capable of stimulating healing by manipulating wound biochemistry.
Platelet-rich plasma (PRP) is a common therapy for acceleration of maxillofacial and spinal fusion bone-graft healing. This study analyzes the therapeutic role of PRP during long-bone fracture healing evaluated Lewis rats. Following creation of unilateral open femur fractures, either 500 microL thrombin-activated PRP (PRP treated group) or 500 microL saline (control group) were applied once to the fracture site. Fracture healing was analyzed after 1 and 4 weeks. Following 4 weeks of fracture healing, radiographic analysis demonstrated higher callus to cortex width ratio (P < 0.05) in the PRP group (PRP: 1.65 +/- 0.06; control: 1.48 +/- 0.05). Three-point load bearing showed increased bone strength following PRP treatment (PRP: 60.85 +/- 6.06 Newton, control: 47.66 +/- 5.49 Newton). Fracture histology showed enhanced bone formation in the PRP group. Immunohistochemistry and Western-blotting demonstrated healing-associated changes in transforming growth factor (TGF)-beta1 and bone morphogenetic protein (BMP)-2. Our results suggest that PRP accelerates bone fracture healing of rat femurs via modulation of TGF-beta1 and BMP-2 growth factor expression.
Renal impairment has long been known to affect wound healing. However, information on differences in the spectrum of wound healing depending on the type of renal insufficiency is limited. Acute kidney injury (AKI) may be observed with different wound types. On one hand, it follows acute traumatic conditions such as crush injury, burns, and post-surgical wounds, and on the other hand, it arises as simultaneous targeting of skin and kidneys by autoimmune-mediated vasculitis. Chronic kidney disease (CKD) and end-stage renal disease (ESRD) often occur in older people, who have limited physical mobility and predisposition for developing pressure-related wounds. The common risk factors for poor wound healing, generally observed in patients with CKD and ESRD, include poorly controlled diabetes mellitus, neuropathy, peripheral vascular disease, chronic venous insufficiency, and aging. ESRD patients have a unique spectrum of wounds related to impaired calcium-phosphorus metabolism, including calciphylaxis, in addition to having the risk factors presented by CKD patients. Overall, there is a wide range of uremic toxins: they may affect local mechanisms of wound healing and also adversely affect the functioning of multiple systems. In the present literature review, we discuss the association between different types of renal impairments and their effects on wound healing and examine this association from different aspects related to the management of wounds in renal impairment patients.
Keloids are the result of aberrant wound healing of human skin after dermal injury. Therapeutic options include excision followed by radiation therapy, steroid injection, and compression with silicone sheets among others. Local invasion and recurrence after excision has provoked interest in treating keloids as neoplasms. The purpose of this study was to determine the effect of mitomycin C (MMC) on keloid fibroblasts. Keloid fibroblasts obtained from five different patients were exposed to MMC. A control group of normal and keloid cells was treated with phosphate buffered saline only. Contrast microscopy showed a decrease of fibroblast density during the 3 weeks after exposure for normal and keloid fibroblasts relative to untreated fibroblasts. This was confirmed by total cell counts ( = 0.1) and measurement of DNA synthesis. By the third week, there was a recovery in DNA synthesis and increased cell count for some of the treated fibroblasts. We concluded that at an appropriate concentration, MMC shows proliferation of keloid fibroblasts in vitro for a period of 3 weeks. This agent may be considered in clinical trials after surgical excision of keloids.
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