Heat shock proteins increase during a race with high exertional heat stroke incidence

Abstract

Abstract Background: Circulating heat-inducible, heat-shock protein 72 [HSP72] responses to exercise-heat stress have been well studied as a potential biomarker of exertional heat illness susceptibility. However, little is known about the responses of other HSPs important to immune responses and pathophysiology. HSP27, -60, and -90 are fundamental HSPs important in cellular proteostasis and pathophysiology associated with immune dysregulation. Therefore, we aimed to characterize responses of HSP27, -60, and –90 during a race known to introduce extreme levels of exercise-heat stress that annually result in high incidences of exertional heat stroke. Methods: Thirty participants (45.3±11.7 yr, 175.6±8.9 cm, 74.9±13.5 kg, 19.7±3.6 % body fat) registered to run in the Falmouth Road Race (Falmouth, MA) were recruited. Gastrointestinal temperature (TGI) and blood plasma HSP27, -60, and -90 (by commercially available ELISA) were measured at pre- (PRE) and post-race (POST). Results: TGI, [HSP27], and [HSP90] increased at POST (p<0.05). HSP concentrations at POST did not correlate with TGI at POST (p>0.05). In conclusion, HSPs are important for constitutive cellular function and measurably increase circulation post-exercise-heat stress. Correlation between HSPs and pre- or post-event core temperature to determine utility as predictive biomarkers require further study.