This article assesses recent studies about stem cell research in dermatology. The interaction of stem cells in the maintenance and repair of the skin, as well as their participation in the hair follicle cycle and its pigmentation, are also discussed. Studying those mechanisms will increase understanding of the pathophysiology of diseases linked to dysfunctions in those processes, which will enable the development of therapeutic approaches to these situations.

Keywords: STEM CELLS, SKIN, DERMATOLOGY

The present article describes Platelet-Rich Plasma, with emphasis on its use in dermatology. The application of this procedure in medicine has become increasingly frequent during the last decade. Most publications on the topic arise from areas such as Orthopaedics, Sports Medicine, and Odontology. In the dermatologic field, Platelet-Rich Plasma has been used in order to promote accelerated wound healing, as an adjuvant treatment in rejuvenation and alopecia, and even after laser sessions. In the present review, the authors used articles published on the subject, attributing the Oxford Centre for Evidence Based Medicine's "Level of Scientific Evidence" classification.

Keywords: BLOOD PLATELETS, DERMATOLOGY, BLOOD

Introduction: Cutaneous fillings are a common procedure in today's dermatology, with the majority being carried out with hyaluronic acid isolated or combined with other substances. Objective: To study the effects of adding hyaluronic acid and polyethylene glycol to cultures of human dermal fibroblasts. Methods: The study evaluated: cell proliferation and production of type 1 collagen (COL1A1) in the presence or absence of anti-CD44 antibodies (membrane receptor for hyaluronic acid); the synthesis of metalloproteinase-1 (mmp-1), of tissue factor inhibitor of metalloproteinase-1 (TIMP - 1) and of transforming growth factor-α (TGF-α) through the analysis of gene expression via PCR (polymerase chain reaction); cell proliferation through the detection of the incorporation of a thymidine analogue in the cellular DNA. Results: Increased proliferation of fibroblasts and collagen synthesis were observed in the cultures exposed to hyaluronic acid, partially inhibited by the presence of anti-CD44 antibodies in the cultures. The exposure of cultures to hyaluronic acid enhances the production of TIMP-1 and TGF - α, and reduces the expression of MMP-1. These effects were not noticed in the cultures exposed to polyethyene glycol. Conclusion: In an in vitro setting, the addition of hyaluronic acid to cultures of human dermal fibroblasts increases proliferation and synthesis of COL1A1, TIMP-1 and TGF-α, decreasing that of MMP-1. The addition of anti-CD44 to the cultures reduces cell proliferation and collagen synthesis, which may indicate the role of that receptor in mediating those events.

Keywords: FIBROBLASTS, HYALURONIC ACID, EXTRACELULAR MATRIX.