Hsp70 Induction and hsp70 Gene polymorphisms as Indicators of acclimatization under hyperthermic conditions

Abstract

The possibility of using Hsp70 and hsp70 gene polymorphisms as markers of acclimatization was investigated. Volunteers (22) were subjected to an acclimatization regimen and blood analysed for Hsp70 (Hsp72) and hsp70 polymorphisms before and after a heat tolerance test. Physiological parameters denoting acclimatization, or not, were correlated to levels of Hsp70 and combination of hsp70 genes. Only individuals that acclimatized had decreased basal Hsp70 levels and increased ability to induce Hsp70 together with a specific hsp70 genotype combination. We propose that Hsp70 levels (basal vs. induced) with the genotype combination have the potential to be used as markers of acclimatization. Article Outline

Heat and exercise acclimation increases intracellular levels of Hsp72 and inhibits exercise-induced increase in intracellular and plasma Hsp72 in humans

“…Only a few studies so far have investigated the effects of HA on extracellular concentration of Hsp72. Earlier, Kresfelder et al (2006) also showed that baseline eHsp72 levels decreased after 5 days of HA, but only in subjects who showed signs of HA, while subjects who were not acclimated showed an increase in eHsp72. More recently, Yamada et al (2007) showed no alterations in eHsp72 after either exercise or HA.…”

“…Studies on the effects of HA on eHsp72 concentration show contrasting results. Extracellular levels of Hsp72 have been shown to decrease after the initial phase (2 days) (Marshall et al 2006) and after 5 days of HA (Kresfelder et al 2006), but no difference was found after a 10-day HA protocol (Yamada et al 2007).…”

Heat acclimation: Gold mines and genes

“…5 South African researchers still today continue to use some of the testing protocols and acclimation procedures developed by Dreosti and Wyndham and they are in the forefront of determining the molecular markers of heat acclimation. 7 The early mine conditions (pre-1940) The first recognized case of heat stroke in the City Deep Mine, one of the first and deepest mines, occurred in 1926. The heat acclimation procedure for new natives employed at this time consisted of 5-10 d of shoveling at a reduced workload as they progressively moved to hotter regions of the mine.…”

“…Recent molecular studies have identified specific HSP polymorphisms that may account for individual differences in heat tolerance. Kresfelder and coworkers, 7 for example identified a subgroup of individuals with a specific HSP70 polymorphism where HSP expression does not increase following a heat exposure. Such individuals also did not respond appropriately during a short heat acclimation protocol.…”

No endogenous circadian rhythm in resting plasma Hsp72 concentration in humans

“…It is also important to determine whether such a response is stable over time. Recent research into the effects of exercise-heat acclimation (HA) has highlighted this importance where resting levels of eHsp72 appear to decrease during HA (Kresfelder et al 2006;Marshall et al 2006). As such, a well-controlled investigation to establish whether resting concentrations of eHsp72 are subject to a circadian rhythm was warranted.…”