RNA sequencing of unmanipulated and saline-injected skin in healthy old adults before and after oral vitamin D3 supplementation

Vitamin D insufficiency may exacerbate non-specific inflammation observed in older adults. Here, we tested the hypothesis that an inflammatory gene signature present in old skin following saline injection (as model for non-specific needle injury) normalizes after oral vitamin D3 supplementation. To define the saline-induced signature, we compared gene expression in skin biopsies taken six hours after saline injection in old adults (=65 years) to biopsies from unmanipulated skin. We then assessed signature expression in saline-injected skin of old and young adults (<40 years), and in paired samples of old adults before and after oral vitamin D3 supplementation (6400 IU/day for 14 weeks), where median serum 25-hydroxyvitamin D increased from 43 nmol/L (interquartile range 36-53 nmol/L) to 131 nmol/L (interquartile range 115-147 nmol/L). This submission comprises 112 samples from 57 individuals.