Joris van Dongen

249 Facial lipografting on skin quality: a systematic review INTRODUCTION Aging of the face is characterized by many changes in a broad spectrum of facial skin features e.g. increased pigmented spots, increasedwrinkle depth and rosacea formation. Aged facial skin can be categorized into two types of aging: intrinsic or programmed aging and extrinsic or photoaged aging. Intrinsic aging is caused by passage of time due to genetic influences, while extrinsic aging is mainly caused by ultraviolet radiation or cigarette smoke. 1,2 Major alterations of both intrinsic as well as extrinsic aging occur in the dermal extracellularmatrix. 3,4 In aged skin, there is a reduced collagen syntheses and increased collagen fiber fragmentation resulting in collagen deficiency and therefore a thinner skin. 3,5 Photoaged skin is often histologically characterized by increased epidermal thickness, damaged dermal connective tissue as well as accumulation of disorganized elastin. 1,6 These extracellular matrix changes result in loss of elasticity and therefore formation of wrinkles over time. In 2006, Coleman was the first to describe that lipografting or lipofilling, the transplantation of adipose tissue, reduced age-related skin changes such as wrinkle depth, pore size and pigmented spots. 7 These “skin rejuvenation” effects were ascribed to the regenerative potential of adipose tissue-derived stromal cells (ASCs). ASCs are attached around vessels as precursor cell types e.g. pericytes and supra-adventitial cells in the stroma i.e. stromal vascular fraction (SVF) of adipose tissue. 8,9 Adipose tissue comprises of parenchyma i.e. adipocytes and SVF that also consists fibroblasts, immune cells and vascular cells. 10,11 ASCs can be enzymatically isolated from large quantities of lipoaspirates and have the ability to remodel extracellular matrix. 12,13 The enzymatic isolation of ASCs sparked an increase in clinical studies with respect to ASC-enriched lipofilling or cell-assisted lipofilling (CAL). 14-16 However, in many countries the use of enzymes and animal derived products to isolate cells ( e.g. ASCs) from human tissue for clinical use is forbidden by legislation. Hypothetically, the animal-derived products increase the risk for zoonosis, while these multistep procedures are considered undesirable manipulations. Therefore, new intraoperative isolation procedures of ASC were developed without the use of enzymes and animal derived products, called mechanical isolation procedures. 11 Most of these mechanical isolation procedures isolate SVF that still contains cell-cell and cell-matrix connections (tSVF), in contrast to enzymatically isolated SVF that is a single cell suspension which obviously lack cell-cell connections and extracellular matrix (cSVF). 11,17 Thus far, no studies have been published using tSVF or tSVF-enriched lipografting for skin rejuvenation purposes. Numerous other publications have described the clinical observation of improved skin quality after lipografting. 7,18-28 This systematic review now was undertaken to evaluate the effect of lipografting on skin quality.