Comparative Efficacy of Stromal Vascular Fraction and Adipose-Derived Stem Cells in Ultraviolet B-Induced Skin Damage in Nude Mice.

<h4>Background</h4>Chronic ultraviolet B (UVB) exposure accelerates skin aging by inducing oxidative stress and inflammation, leading to dehydration, reduced collagen density, and impaired epidermal and dermal integrity. Stem cell-based therapies, including the use of the stromal vascular fraction (SVF) and adipose-derived stem cells (ASCs), have emerged as promising approaches for skin regeneration.<h4>Objectives</h4>The authors of this study evaluated the therapeutic effects of SVF and ASCs on UVB-induced skin damage.<h4>Methods</h4>The mice were exposed to UVB irradiation (290-310 nm) for 8 weeks to establish a photoaging model. Following UVB exposure, the SVF or ASCs were injected into the dorsal skin, and the skin samples were analyzed.<h4>Results</h4>UVB exposure significantly reduced skin hydration (-26%), decreased collagen density, and led to a decrease in the thickness of the epidermal and dermal layers. The SVF and ASC treatments improved skin hydration, enhanced extracellular matrix remodeling, and increased collagen density. Both treatments reduced oxidative stress by decreasing reactive oxygen species levels, with SVF-treated samples exhibiting increased BMAL1 expression. SVF and ASCs also promoted angiogenesis and lymphangiogenesis. A reduction in macrophage infiltration and a shift in polarization from the proinflammatory M1 phenotype to the anti-inflammatory M2 phenotype were also observed in the SVF and ASC groups, with ASCs exhibiting stronger immunomodulatory effects. The SVF and ASCs each displayed distinct therapeutic advantages in skin tissue restoration.<h4>Conclusions</h4>These findings highlight the potential of the SVF and ASCs as therapeutic strategies for UVB-induced skin aging, warranting further clinical investigation.