The researchers used human dermal fibroblasts and ex vivo human skin explants to assess fibroblast proliferation, cellular senescence, melanogenesis, inflammatory markers and extracellular matrix biosynthesis.  

Both exosome types increased fibroblast proliferation and reduced senescence. However, adipose-derived MSC exosomes showed higher vascular endothelial growth factor content and were associated with greater collagen and hyaluronic acid production. Umbilical cord-derived MSC exosomes were enriched in transforming growth factor-beta and platelet-derived growth factor-BB, demonstrating stronger immunomodulatory activity and greater reduction of senescence-associated inflammatory markers in ultraviolet-damaged skin.  

Both exosome types also reduced melanogenesis without affecting melanocyte viability, suggesting potential relevance for pigmentation-related skin ageing.  

The authors conclude that the two exosome sources have distinct but complementary regenerative profiles, with adipose-derived exosomes favouring dermal matrix remodelling and hydration, while umbilical cord-derived exosomes showed stronger anti-inflammatory and photoprotective effects. 

For UK clinical context, human-derived exosome products are not permitted for use.