Effects of whole-body heat acclimation on cell injury and cytokine responses in peripheral blood mononuclear cells

Abstract

To test the hypothesis that whole-body heat acclimation (HA) would increase peripheral blood mononuclear cells' (PBMC) tolerance to heat shock (HS) and/or alter the release of cytokines (IL-1β, IL-6, IL-10 and TNF-α) to bacterial lipopolysaccharide (LPS), we heat acclimated nine subjects by exercising them for 100 min in a hot environment for 10 days. The subjects' PBMC were separated and cultured on days 1 and 10 of HA pre- and post-exercise. Pre-exercise PBMC were allocated to three treatments: control (PRE, 37°C), HS (42.5°C for 2 h), or LPS (1 ng mL(-1) for 24 h). Post-exercise samples were incubated at 37°C. PBMC lactate dehydrogenase release increased (p < 0.05) after HS but it was not different (p > 0.05) between days 1 and 10 (0.100 ± 0.012 and 0.102 ± 0.16 abs., respectively). LPS treatment induced an increased (p < 0.05) release of cytokines but HA did not alter this response (p > 0.05). Pre-exercise intracellular heat shock protein 72 (Hsp72) was higher (p < 0.05) on day 10 compared to day 1 of HA (13 ± 5 and 8 ± 5 ng mL(-1), respectively). HS treatment caused a greater increase (p < 0.05) in Hsp72 than the exercise sessions on HA days 1 and 10. In addition, after HA, the Hsp72 response to HS was reduced (day 1, 129 ± 46; day 10, 80 ± 32 ng mL(-1), p < 0.05). In conclusion, HA increases PBMC Hsp72 but it does not reduce cellular damage to HS or alter cytokine response to LPS. We speculate that the stress applied during HA is not sufficient to modify the PBMC response.

Reduced Hsp70 and Glutamine in Pediatric Severe Malaria Anemia: Role of hemozoin in Suppressing Hsp70 and NF-κB Activation

“…Consistent with this notion, we and others have demonstrated that overexpression of Hsp70 protein blocks nuclear translocation of NF-κB and thereby reduces proinflammatory mediator production (19)(20)(21)50). Although the role of Hsp70 in modulating the inflammatory response through interference with NF-κB activation has been shown in several diseases (9, [74][75][76], the link between Hsp70, NF-κB activation and cytokine production has not been established in human malaria. However, a number of previous in vitro studies have shown that hemozoin and other parasitic products…”

Extracellular Hsp72 concentration relates to a minimum endogenous criteria during acute exercise-heat exposure

“…) and the delta change in T rec (VHOT 2.22±0.65°C), it may be more appropriate to implement an isothermic (controlled hyperthermia) model of exercise-heat exposure (Garrett et al 2009(Garrett et al , 2011(Garrett et al , 2012 where the rate of heat production can be accelerated (Amorim et al 2008) and proposed minimum endogenous temperatures targeted (Amorim et al 2011). This model requires greater exercise intensity during the early stages of the exposure, thus ensuring a more rapid increase in T rec and consequently greater change in T rec , followed by a reduction in workload once a desired temperature has been achieved.…”

“…Research has identified extracellular changes in Hsp72 concentration within whole blood (Marshall et al 2006;Yamada et al 2007;Ogura et al 2008;Magalhães et al 2010;Périard et al 2012), and intracellular changes in total protein expression and/or gene transcription in monocytes and systemic tissue (McClung et al 2008;Selkirk et al 2009;Magalhães et al 2010;Amorim et al 2011) in response to thermal and exercise stress. Hsp72 binds with high affinity to the plasma membrane (Asea et al 2000) and up-regulates expression of pro-inflammatory cytokines, tumour necrosis factor-α, interleukin-1β and interleukin-6 in human monocytes.…”

Heat shock response and autophagy—cooperation and control

“…144 Similarly, a 10-d acclimation program involving treadmill walking or running in a hot environment augments HSP70 content in peripheral blood mononuclear cells. 143,167,168 Elevation of HSP70 in response to high-intensity and long-term training is also found after an 11-d training program, but not in response to short or moderate intensity exercise. 146,[169][170][171][172] Besides exercise intensity, training status and the type of exercise seem to exert considerable effect on HSP70 expression.…”