Stratum corneum hydration inversely correlates with certain serum cytokine levels in the elderly, possibly contributing to inflammaging

BACKGROUND: Chronic, low-grade inflammation, also termed 'inflammaging(definition)', has been linked to the development of some aging-associated disorders. Recent studies suggest that inflammaging is attributable to aging-associated epidermal dysfunction. However, abnormality in which epidermal function contributes to inflammaging is not clear. OBJECTIVE: We delineated the correlation of epidermal functions with circulating levels of proinflammatory cytokines in the elderly. METHODS: Blood sample was collected from a total of 255 participants aged ≥ 65 years. Epidermal biophysical properties were measured on the left forearm and the right shin. Serum cytokine levels were measured by Multiplex Luminex Assays. RESULTS: Neither skin surface pH nor transepidermal water loss rates (TEWL) correlated with serum cytokine levels except TEWL on the right shin for TNFa (p < 0.05). In contrast, stratum corneum hydration levels on both the forearm and the shin correlated negatively with serum cytokine levels (p < 0.05). CONCLUSION: Reduced stratum corneum hydration likely contributes to inflammaging.