The influence of age and gender on serum dehydroepiandrosterone sulphate (DHEA-S), IL-6, IL-6 soluble receptor (IL-6 sR) and transforming growth factor beta 1 (TGF-beta 1) levels in normal healthy blood donors

Dysregulation of IL-6 synthesis is thought to play a role in the developmen t of a number of age-related conditions, such as rheumatoid arthritis, oste oporosis, atherosclerosis, Alzheimer's disease and B cell malignancies. Rec ently it has been suggested that the production of IL-6 is influenced by th e adrenal hormone dehydroepiandrosterone (DHEA) and its sulphated derivativ e DHEA-S. In humans we investigated the relationship between DHEA-S, IL-6, IL-6 sR and TGF-beta 1 in the serum of normal healthy male and female blood donors. Using immunoassay techniques we found that the serum levels of DHE A-S significantly (P = 0.0001) decreased with age in both males and females . Furthermore, mean DHEA-S levels in all age groups were significantly (P = 0.0001) higher-in males. Such correlations were not apparent for IL-6 usin g a standard assay, but a high sensitivity assay revealed that serum IL-6 w as significantly (P=0.0018) positively correlated with age in males only. I n addition, serum levels of DHEA-S were significantly (P=0.048) negatively correlated with serum IL-6, again in male subjects only. In contrast, serum IL-6 sR and TGF-beta 1 levels were not correlated with age in either males or females and were not significantly different between the sexes. However , a significant (P=0.024) negative correlation between DHEA-S and IL-6 sR w as found in males. These studies clearly highlight the complex nature of th e relationship between these molecules in the ageing process in normal heal thy blood donors and demonstrate the need to use high sensitivity assays wh en measuring IL-6 in apparently healthy individuals under the age of 70 yea rs.