Inflammatory status as an important determinant of heat shock protein 70 serum concentrations during aging

Heat shock proteins (Hsp) form a large family of proteins that are ubiquitously present in all organisms. In the absence of destabilising stimuli, Hsp are expressed at low levels, but their expression can be highly induced by various noxious conditions such as heat, oxygen stress and infection. Hsp have been reported to interfere with inflammatory processes and their induction is well known to decrease with aging. In the present study we have investigated Hsp 70 serum concentrations using an optimised ELISA in elderly patients, recruited from a geriatric University Hospital ward. Our results portray positive correlations between the serum levels of Hsp 70 and various markers of inflammation (monocyte count, serum concentration of TNF-alpha, plasma concentrations of C-reactive protein, and fibrinogen), explaining the difference in Hsp 70 serum concentrations in these subjects with various degrees of inflammation. We conclude that Hsp 70 is involved in inflammatory diseases and that the serum level of Hsp 70 is directly linked to the inflammatory status of the subject. However, the nature of this relationship remains to be elucidated.