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J Appl Physiol 103: 1251-1256, 2007. First published August 2, 2007; doi:10.1152/japplphysiol.00484.2007
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Effect of exercise with and without a thermal clamp on the plasma heat shock protein 72 response

Martin Whitham,1 Stewart J. Laing,2 Anna Jackson,2 Norbert Maassen,3 and Neil P. Walsh1

1School of Sport, Health and Exercise Sciences, University of Wales, Bangor; 2Olympic Medical Institute, Northwick Park Hospital, Harrow, United Kingdom; and 3Sports and Exercise Physiology, Medical School Hannover, Hannover, Germany

Submitted 4 May 2007 ; accepted in final form 31 July 2007


   ABSTRACT
TOP
 ABSTRACT
MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 ACKNOWLEDGMENTS
 REFERENCES
 
The contribution of heat and exercise related stress to the release of heat shock protein 72 (HSP72) is currently unknown. The purpose of the present study was to determine the combined and independent effects of heat and exercise on the extracellular (e)HSP72 response. Eleven moderately trained male volunteers [means ± SD: age 21 ± 4 yr; body mass 75.7 ± 7.7 kg; maximal oxygen uptake (VO2 max) 57.8 ± 3.3 ml·kg–1·min–1] completed four 2-h, heat-manipulated, water-immersion trials. Trials were exercise-induced heat (EIH; rectal temperature change +2.2°C), clamped exercise (CEx; 0°C), passive heating (PHT; +2.3°C), and control (Con; 0°C). Exercise trials (EIH and CEx) comprised deep-water running at 58.5 ± 2.4 and 59.1 ± 1.7% vo2max. eHSP72 and catecholamine concentrations were determined by ELISA and HPLC, respectively, pre- and postimmersion. All trials induced an eHSP72 response (P < 0.05) with postimmersion values significantly greater on EIH compared with other trials (6.0 ± 3.4; CEx 3.8 ± 2.6; PHT 2.7 ± 2.1; Con 2.2 ± 1.9 ng/ml). Exercising with a thermal clamp blunted the eHSP72 response, but postimmersion values were also greater than Con. PHT induced a large catecholamine response, but postimmersion eHSP72 values did not reach significance vs. Con. Given that exercising with a thermal clamp evoked a significant increase in plasma eHSP72 concentration, exercise-related stressors other than heat appeared influential in stimulating HSP72 release. Moreover, the catecholamine data from PHT suggest neither epinephrine nor norepinephrine was solely responsible for eHSP72 release.

stress; hyperthermia; immunity

HEAT SHOCK PROTEIN 72 (HSP72) is the highly stress-inducible isoform of the heat shock protein 70 family. As such, HSP72 has been detected in the circulation of humans in response to exercise (12, 26, 46) and trauma (35). While commonly considered an intracellular chaperone with roles in protein homeostasis, the appearance of HSP72 in the extracellular environment has generated interest in the possible systemic roles of this protein. For example, extracellular (e)HSP72 has been hypothesized to play a number of roles in modulating the immune system, such as the stimulation of proinflammatory cytokines (1), activation of the complement cascade (36) and activation of CD40+ antigen-presenting cells (47). Furthermore, in vitro experiments suggest that exogenous HSP72 can bind to cells, penetrate the plasma membrane and protect cells from cytotoxicity (19, 33). Indeed, correlative data exist that suggest that extracellular HSP72 concentration is associated with improved survival in severe trauma patients (35). Moreover, resting eHSP72 appears to decrease with repeated heat stress, perhaps as a consequence of increased uptake by cells requiring improved stress tolerance (28). While extracellular HSP72 appears to play an important role in the response to stress, the mechanisms involved in the release of HSP72 into the circulation remain to be elucidated.

The term "heat shock protein" is perhaps misleading, because it is apparent that the intracellular concentration of HSP72 can be increased following nonthermal stressors such as glycogen depletion (11), high acidity (48), Ca2+-increasing agents (8), and a number of stress hormones such as corticosterone (43) and epinephrine or norepinephrine (29, 45). Furthermore, data from rats suggest that while the combined stressors of 60 min of treadmill running and whole body hyperthermia (41°C) induced the largest intracellular HSP72 response, exercising in a cool environment, with no measurable increase in core temperature, also induced a significant increase in skeletal muscle and cardiac HSP72 (40). Therefore, by measuring the HSP72 response to exercise during a thermal clamp, the authors where able to assert that in this animal model, factors other than heat stress contribute to the intracellular HSP72 response to exercise. Conversely, in repeatedly (3 x 30 min/day) exercising rats in thermally clamped conditions, Hamilton et al. (20) did not observe an increased myocardial HSP72 content compared with rats exercising at room temperature. The effect of heat and exercise may therefore be dependent on the tissue in which HSP72 is measured and the frequency or duration of the exercise (16, 30).

If the extracellular concentration of HSP72 were to simply reflect a spillover of intracellular concentrations, then one might expect to see similar trends in extracellular HSP72 that are seen in the intracellular protein concentrations in response to exercise. Indeed, one mechanism by which eHSP72 might increase in the circulation is via leakage from cellular necrosis (2). However, experiments demonstrating eHSP72 responses to exercise have used protocols not thought to cause significant cell damage (10, 32), and the induction of eHSP72 in response to psychological (rather than physical) stress in animals (15) suggests there is an alternative means of HSP72 trafficking. In vitro data from a number of laboratories suggest that the release of HSP72 from monocytes (23, 25) and epithelial cells (4) is via a nonclassical secretory pathway. Furthermore, through the use of {alpha}- and beta-adrenergic blockade in rats, Johnson et al.(24) were able to provide convincing data to support the involvement of catecholamines in the eHSP72 response to tail shock. While the involvement of catecholamines in the stimulated release of eHSP72 has been supported in a human exercise model (49), the role of hyperthermia in the specific release of eHSP72 during exercise is unclear.

The aim of the present research was first to determine the combined and independent effects of exercise and hyperthermia on the eHSP72 response in humans. We hypothesized that exercise inducing whole body hyperthermia would result in the largest eHSP72 response, whereas exercise alone and hyperthermia alone would also induce significant but smaller HSP72 responses. Because exercise with and without a thermal clamp induces different stress hormone responses (38), the second aim was to further examine the role of stress hormones in the eHSP72 response to stress.


   MATERIALS AND METHODS
TOP
 ABSTRACT
 MATERIALS AND METHODS
RESULTS
 DISCUSSION
 ACKNOWLEDGMENTS
 REFERENCES
 
Subjects.   Eleven healthy, moderately trained men volunteered to participate following local ethics approval and written informed consent. Subject characteristics were as follows (means ± SD): age 21 ± 4 yr; body mass 75.7 ± 7.7 kg; maximal oxygen uptake (VO2 max) 57.8 ± 3.3 ml·kg–1·min–1.

Preliminary testing and experimental design.   Before experimental trials, all subjects carried out a standard continuous incremental treadmill exercise test to volitional exhaustion to determine individual VO2 max. Expired gases were analyzed continuously using an online gas analysis system (metalyser 3B, Cortex, Leipzig, Germany) with the VO2 max values derived thereby used to determine the work rate of subsequent exercise trials. At this initial visit, subjects were also familiarized with deep-water running exercise, completing a 30-min exercise bout immersed in water to the shoulder level and supported by a harness and ropes to aid buoyancy. Subjects were then asked to return to the laboratory a further four times to carry out the experimental immersion trials in a randomized order. Each trial was separated by 7 days.

Experimental trials.   During all trials, chamber water was manipulated to the desired temperature and monitored continuously using temperature thermisters (Edale, Cambridge, UK) at various positions in the chamber. All trials were 2 h in duration. To determine the effects of hyperthermia and exercise on the outcome variables, subjects carried out the exercise-induced heat trial (EIH; water temperature 35.3 ± 0.2°C) during which rectal temperature was intended to significantly increase. To investigate the effect of hyperthermia alone, the passive heating trial (PHT; 38.5 ± 0.2°C) involved seated immersion in hot water during which rectal temperature was also intended to significantly increase. To determine the effects of exercise alone (i.e., a thermally clamped exercise bout), subjects carried out the clamped exercise trial (CEx; 23.5 ± 0.9°C). Finally, to control for time of day effects and the influence of immersion alone, subjects carried out the control trial (Con; 35.3 ± 0.2°C). Before all trials, subjects were asked to refrain from carrying out vigorous physical activity and consuming alcohol and caffeine for the preceding 24 h. To standardize nutritional status, subjects were asked to record and replicate dietary intake the day before each trial. At 0800 of the morning of each trial, subjects were provided with a standardized breakfast (816 kcal; carbohydrate 78%, fat 14%, and protein 8%) and consumed only water before beginning each trial at 1200. Before immersion, each subject was asked to empty their bladder and bowels before nude body mass was determined (model 705, Seca, Hamburg, Germany). To ensure euhydration, urine osmolality was determined using freezing-point depression osmometry (Advanced Instruments, Needham Heights, MA) using the threshold for hydration of 700 mosmol/kgH2O (39). Subjects were then seated for 15 min before a resting blood sample was taken by venipuncture of an anitcubital vein. On commencement of each and every trial, subjects were immersed to the shoulder level suspended by a harness and ropes to aid buoyancy. The exercise trials (EIH and CEx) comprised deep water running (37) at ~60% VO2 max. Oxygen consumption during these bouts was monitored via Douglas bag collections every 10 min (Harvard Apparatus, Edenbridge, UK) and measured using a dry-gas meter (Harvard Apparatus) and combined paramagnetic oxygen and infrared carbon dioxide analyzer (1420B, Servomex, Crowborough, UK). On immediate completion of all trials, subjects were removed from the immersion chamber. and another venous blood sample was taken in a seated position. Nude body mass was assessed as described above to determine body mass losses corrected for ad libitum water consumption throughout all trials. All subjects remained fasted for a further 60 min before the final venous blood sample was taken.

Measures.   Throughout all trials, heart rate was measured by telemetry (Polar Electro Oy, Kempele, Finland) and subjects were asked to rate their perceived exertion (RPE) (3) and thermal comfort (22). Rectal temperature was monitored using a thermister probe (model 4000A, Yellow Springs Instruments, Daytona, OH) inserted 10 cm beyond the anal sphincter. Expired gas, heart rate, RPE, thermal comfort, and rectal temperature were recorded every 10 min.

Analytical methods.   Blood samples were collected into EDTA (1.6 mg EDTA/ml blood)- and heparin (1.5 IU heparin/ml blood)-coated tubes. Following centrifugation at 1,500 g for 10 min (4°C), resulting plasma samples were frozen and stored at –80°C for later analysis. Plasma epinephrine and norepinephrine were determined by high-pressure liquid chromatography (Clinrep complete kit for catecholamines, Recipe Chemicals, Munich, Germany) as previously described (5). Plasma cortisol was determined in duplicate in heparinized plasma by ELISA (DRG Diagnostics, Marlburg, Germany). EDTA plasma was analyzed for HSP72 in duplicate by a commercially available ELISA (Stressgen, Victoria, Canada). Intra-assay coefficient of variation was 3.1, 7.8, 11, and 3.2% for cortisol, epinephrine, norepinephrine, and HSP72, respectively. Hemoglobin and hematocrit were determined from whole blood treated with EDTA using an automated cell counter (Gen S, Beckman Coulter, Fullerton, CA). Using these data, plasma volume change was calculated as previously described (7), and all hormone and HSP72 data were corrected accordingly.

Statistics.   Adequate sample size was calculated a priori using means and SDs of plasma HSP72 exercise responses reported previously (49). Using a freely available web-based power calculator (www.dssresearch.com/toolkit/sscalc), a total of 11 subjects was deemed to provide adequate statistical power ({alpha} = 0.01, beta = 0.9). Data were examined using trial (4) x time (3) fully repeated-measures ANOVA and eta squared effect size ({eta}2) correcting for violations of homogeneity and sphericity using the Greenhouse-Geisser method, where appropriate. Significant interactions were further examined by post hoc Tukey's honestly significant difference test or Bonferroni pairwise comparisons depending on the value of epsilon (42). Statistical significance was accepted at P < 0.05, and data are presented as means ± SE unless otherwise stated.


   RESULTS
TOP
 ABSTRACT
 MATERIALS AND METHODS
 RESULTS
DISCUSSION
 ACKNOWLEDGMENTS
 REFERENCES
 
In the two exercise trials, mean exercise intensity was 58.5 ± 2.4 and 59.1 ± 1.7% VO2 max in EIH and CEx, respectively. There was a significant time x trial interaction for rectal temperature (P < 0.001, {eta}2= 0.87). As expected, follow-up tests revealed that (after 20 min) EIH and PHT induced significantly greater rectal temperatures than CEx and Con (Fig. 1). Because there were no significant increases in rectal temperature in CEx, the protocol was successful in clamping core temperature. Furthermore, there were no significant differences in rectal temperature between EIH and PHT at any time point (P < 0.05). As anticipated, thermal sensation reflected these trends in core temperature (Fig. 2). There was a significant increase in heart rate in all trials except Con (Fig. 2). As expected, heart rates recorded during exercise trials were significantly greater than seated immersion trials and in line with established literature: heat stress induced a greater heart rate response than non-heat-stress trials (EIH > CEx; PHT > Con). Heat stress also significantly increased ratings of perceived exertion in EIH and, unexpectedly in PHT (Fig. 2). The increase in RPE in PHT likely reflects an increase in perceived dyspnea during this seated trial. There were no significant differences in percentage of body mass loss between EIH, CEx, and PHT. Additionally, there were no differences in plasma volume change observed between trials (P = 0.071, {eta}2 = 0.2; EIH –7.1 ± 5.1%, CEx –9.3 ± 3.5%, PHT –8.7 ± 6.1%, Con –3.8 ± 3.7%).


Figure 1
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  		Fig. 1. Rectal temperatures (Trec) during exercise with (CEx) and without (EIH) a thermal clamp and during resting immersion in hot (PHT) and thermoneutral (Con) water. Values are means ± SE for 11 subjects. HSD indicates Tukey's honestly significant difference value (P < 0.05).

 

Figure 2
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  		Fig. 2. Thermal sensation (A), rating of perceived exertion (RPE; B), and heart rate (C) during exercise with (CEx) and without (EIH) a thermal clamp and during resting immersion in hot (PHT) and thermoneutral (Con) water. Values are means ± SE for 11 subjects. HSD indicates honestly significant difference value (P < 0.05).

 
Stress hormone responses.   It is well established that both exercise (38) and heat stress (31) induce a stress hormone response. Consistent with this, there was a significant time x trial interaction for epinephrine (P < 0.001, {eta}2 = 0.41) with no intertrial differences observed at preexercise or 1 h postexercise (Table 1). Post-trial values were significantly increased from preimmersion in EIH, PHT, and CEx. These epinephrine responses were significantly greater than Con in EIH and PHT, whereas the difference between CEx and Con approached significance. There was a significant time x trial interaction (P < 0.001, {eta}2 = 0.54) for norepinephrine, with post hoc tests revealing significant increases from baseline in all trials (Table 1). EIH and PHT caused a significantly greater increase in noradrenaline than Con. Exercising with an increase in core temperature (EIH) also caused a significantly greater increase in norepinephrine than exercise alone (CEx). Whole body hyperthermia, therefore, induced the largest increases in circulating catecholamine concentrations whether induced by exercise (EIH) or passive heating (PHT). As expected, there were also significant effects of trial and time on plasma cortisol concentration (P < 0.001, {eta}2 = 0.6;8 Fig. 3). Once again, hyperthermia was associated with the largest increases from baseline in EIH and PHT, which remained significantly elevated 1h post immersion. There was no significant increase in cortisol associated with exercising in a cool environment (CEx; P = 0.14), and there was a significant drop in cortisol observed in Con (P = 0.004, {eta}2 = 0.43). The decrease in cortisol from baseline in this control condition likely reflects the commonly observed circadian rhythm of this hormone (50).


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  		Table 1. Catecholamine responses to EIH, PHT CEX, and Con immersion trials

 

Figure 3
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  		Fig. 3. Cortisol responses to exercise with (CEx) and without (EIH) a thermal clamp and during resting immersion in hot (PHT) and thermoneutral (Con) water. Values are means ± SE for 11 subjects. HSD indicates honestly significant difference value (P < 0.05).

 
Extracellular HSP72 responses.   The eHSP72 data exhibited a significant trial x time interaction (P < 0.001, {eta}2 = 0.55; Fig. 4), with post hoc tests revealing a significant increase in eHSP72 in all trials (including Con) that remained elevated 1 h postimmersion in EIH and CEx. As expected, and in line with our hypothesis, the combined stress of exercise and hyperthermia resulted in the largest increase in eHSP72 in EIH. Indeed, eHSP72 concentrations in EIH were significantly higher than all other trials. The independent effects of passive heating (PHT) and exercise alone (CEx) also induced significantly increased eHSP72 in circulation, with CEx eHSP72 concentrations significantly higher than Con. Although mean postimmersion concentrations in PHT were higher than Con, these differences did not reach significance. A repeated-measures ANOVA on resting eHSP72 concentration revealed no main effect of time (P = 0.68), suggesting that there were no latent effects of previous trials on the eHSP72 response. In all, these data suggest that both heat and exercise factors are involved in the release of eHSP72 into the circulation.


Figure 4
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  		Fig. 4. Plasma heat shock protein 72 (HSP72) responses to exercise with (CEx) and without (EIH) a thermal clamp and during resting immersion in hot (PHT) and thermoneutral (Con) water. Values are means ± SE for 11 subjects. pre, Preimmersion, post, postimmersion; 1h post, 1 h postimmersion. *Significant within-trial increase from pre, P < 0.05. #Significant difference from control trial (Con), P < 0.05. aSignificant difference from CEx, P < 0.05. bSignificant difference from PHT, P < 0.05.

 

   DISCUSSION
TOP
 ABSTRACT
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
ACKNOWLEDGMENTS
 REFERENCES
 
The present research aimed to determine the combined and independent effects of hyperthermia and exercise on the eHSP72 response in humans. There were significant eHSP72 responses to exercise in a thermoneutral environment (EIH), passive heating (PHT), exercise with no increase in core temperature (CEx), and immersion alone (Con). As expected, and in line with data from animal skeletal muscle HSP72 (40), exercise and whole body hyperthermia combined to induce the largest eHSP72 response. The finding of a significant increase in eHSP72 following exercise with a thermal clamp supports the notion that exercise factors other than heat can stimulate the release of HSP72. Interestingly, the effect of passive heating did not induce a large eHSP72 response, despite rectal temperatures reaching similar values to those in the thermoneutral exercise condition (Fig. 1). Furthermore, the difference in postimmersion values between PHT and Con did not reach significance. Indeed, Marshall et al. (28) have also reported that 2 h of passive heating at 38°C and 60% relative humidity had no effect on eHSP72 concentrations. Heat per se, therefore, appeared to have less influence on the release of HSP72 than factors associated with exercise.

The exact stimuli of HSP72 release are currently unclear. Data reported in both animal and human models support the role of catecholamines in the stimulated release of HSP72 (24, 49). Through the use of adrenergic blockade, Johnson et al. (24) were able to assert that HSP72 release during tail shock in rats is mediated by a mechanism involving {alpha}1-adrenoreceptors. Furthermore, using the adrenergic stimulating properties of caffeine, Whitham et al. (49) were able to show significantly greater eHSP72 responses to exercise with caffeine vs. exercise without. Although not implying cause and effect, the present data can also provide some support for the role of catecholamines in the stimulated release of eHSP72. In particular, there were significant norepinephrine responses in all trials that were associated with increases in eHSP72. The observed increase in eHSP72 in the control trial was unexpected and could reflect an effect of time of day or psychological stress associated with confinement in the immersion chamber. Indeed, data in an animal model support the view that eHSP72 can be released following nonphysical stressors (15). Current work is underway in our laboratory to determine whether there are time of day effects for eHSP72. That postimmersion norepinephrine concentrations were also elevated in the control condition provides support for the role of this hormone in the stimulated release of HSP72. However, as indicated, eHSP72 responses to passive heating were not substantial and indeed, did not reach significance when compared with Con. Because catecholamine responses to passive heating were generally large, these data suggest that neither epinephrine nor norepinephrine were solely responsible for the stimulation of eHSP72, and other factors were likely to have contributed. Similarly cortisol responses were not associated with alterations in eHSP72 concentrations, which supports previous data in predatory and tail shock-stressed animals (15, 24) and exercising humans (49) that cortisol is not primarily involved in the stimulation of HSP72 release.

Despite the apparent ubiquity of intracellular HSP72, the origins of eHSP72 during exercise are currently unclear. Unfortunately the present study is unable to further add to the literature in this regard. However, this is important, because the specific releasing mechanism appears to some degree to depend on the cell from which HSP72 is released. For example, while Broquet et al.(4) provided support for the involvement of lipid rafts in the specific release of HSP72 from epithelial cells, Lancaster and Febbraio (25) demonstrated increased exosomal HSP72 content following heat shock of peripheral blood mononuclear cells. Because the rate of exocytosis of these vesicles appears calcium dependent (21) and {alpha}-adrenergic receptors are thought to mediate their actions through alteration of intracellular calcium (17), adrenergic stimulation of exosomal release may well be a mechanism by which various cells release HSP72. To date, it has not been possible to pinpoint the exact tissues or cells that add to circulating HSP72 concentration during exercise. However, through elaborate cannulation across various tissue beds, experiments carried out by Febbraio et al.(10, 11, 26) suggested the brain, hepatosplanchnic tissues, but not intact skeletal muscle at least partly contributed to the circulating HSP72 concentration during prolonged cycling. Interestingly, by supplementing with exogenous glucose and reducing metabolic stress on the liver, the authors were able to blunt the hepatosplanchnic release of HSP72 during moderate exercise (9). Therefore, heightened metabolic stress and subsequent HSP72 release from the liver may partly explain the larger eHSP72 responses to exercise trials observed in the present study. Tissues and cells may have different reserves of HSP72 (14), perhaps dependent on the nature of the stress incurred. This may subsequently be reflected in circulating eHSP72 concentrations and in this regard, further research to determine the potential origin of eHSP72 is warranted.

While the present research has suggested a lessened effect of passive heating on the eHSP72 response, it should be acknowledged that the rectal temperatures recorded at the end of the trial (38.55°C) were lower than have been presented in previous literature. Furthermore, although Marshall et al. (28) concluded that 2 h of passive heating in a 38°C environment had no effect on eHSP72 concentration, no core temperature data were included. Indeed, when clamping core temperature in exercising rats, studies have shown little or no cardiac HSP72 expression (20, 44). In addition, passive heating to tympanic temperatures of 39°C increased HSP72 expression in the leukocytes of humans (34). While the intracellular HSP72 concentrations in these tissues and cells might not necessarily reflect circulating concentrations, it should be considered that the core temperatures reached in the present study were less effective in inducing a heat shock protein response. The finding of Ruell et al. (6) of higher concentrations of eHSP72 in athletes suffering exertional heat illness (41°C) vs. controls (39.8°C) adds weight to this assertion. As the name suggests, heat has a strong influence on heat shock protein transcription. Although the mechanisms involved are unconfirmed, data suggest the regulator of heat shock protein synthesis, heat shock transcription factor 1, is directly activated by temperature (18, 41, 51). So, although the present study intimates that the release of HSP72 when passively heated is relatively small, the effect might be more pronounced at core temperatures approaching 40°C. Nevertheless, the current data are still applicable to previous literature demonstrating an increase in eHSP72 in response to prolonged exercise during which core temperatures did not reach levels associated with heat illness (10, 12, 13, 46).

Despite this limitation, the present investigation's finding of a significant eHSP72 response to exercise with a thermal clamp provides support for the notion that factors other than heat stimulate the release of HSP72. Cellular upregulation of HSP72 occurs following many stresses, including oxidative stress, pH disturbances, hypoxia, and glucose deprivation (27), all of which could occur during the disturbed homeostasis caused by exercise. In particular reference to eHSP72, Fischer et al. (13) were able to demonstrate reduced serum HSP72 in exercising participants supplementing with antioxidants. Therefore, reactive oxygen species may well be one of the factors stimulating HSP72 release during exercise.

To conclude, the present investigation suggests that because exercising with a thermal clamp did not abolish the eHSP72 response, factors other than heat are capable of stimulating the release of HSP72 during exercise. The present data also suggest that neither epinephrine nor norepinephrine was solely responsible for the increase in eHSP72; hence it is likely other stimulators are additionally involved.


   ACKNOWLEDGMENTS
TOP
 ABSTRACT
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 ACKNOWLEDGMENTS
REFERENCES
 
The authors thank Hanelore Konrad for technical assistance.


   FOOTNOTES
 

Address for reprint requests and other correspondence: M. Whitham, School of Sport, Health and Exercise Science Univ. of Wales, Bangor Holyhead Rd., Bangor LL57 2PZ, UK (e-mail: m.whitham{at}bangor.ac.uk)

The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.


   REFERENCES
TOP
 ABSTRACT
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 ACKNOWLEDGMENTS
 REFERENCES
 

  1. Asea A, Kraeft SK, Kurt-Jones EA, Stevenson MA, Chen LB, Finberg RW, Koo GC, Calderwood SK. HSP70 stimulates cytokine production through a CD14-dependant pathway, demonstrating its dual role as a chaperone and cytokine. Nat Med 6: 435–442, 2000.[CrossRef][Web of Science][Medline]
  2. Basu S, Binder RJ, Suto R, Anderson KM, Srivastava PK. Necrotic but not apoptotic cell death releases heat shock proteins, which deliver a partial maturation signal to dendritic cells and activate the NF-kappa B pathway. Int Immunol 12: 1539–1546, 2000.[Abstract/Free Full Text]
  3. Borg GA. Psychophysical bases of perceived exertion. Med Sci Sports Exerc 14: 377–381, 1982.
  4. Broquet AH, Thomas G, Masliah J, Trugnan G, Bachelet M. Expression of the molecular chaperone Hsp70 in detergent-resistant microdomains correlates with its membrane delivery and release. J Biol Chem 278: 21601–21606, 2003.[Abstract/Free Full Text]
  5. Chudalla R, Baerwalde S, Schneider G, Maassen N. Local and systemic effects on blood lactate concentration during exercise with small and large muscle groups. Pflügers Arch 452: 690–697, 2006.[CrossRef][Web of Science][Medline]
  6. Desruelle AV, Candas V. Thermoregulatory effects of three different types of head cooling in humans during a mild hyperthermia. Eur J Appl Physiol 81: 33–39, 2000.[CrossRef][Web of Science][Medline]
  7. Dill DB, Costill DL. Calculation of percentage changes in volumes of blood, plasma, and red cells in dehydration. J Appl Physiol 37: 247–248, 1974.[Free Full Text]
  8. Ding XZ, Smallridge RC, Galloway RJ, Kiang JG. Increases in HSF1 translocation and synthesis in human epidermoid A-431 cells: role of protein kinase C and [Ca2+]i. J Investig Med 44: 144–153, 1996.[Web of Science][Medline]
  9. Febbraio MA, Mesa JL, Chung J, Steensberg A, Keller C, Nielsen HB, Krustrup P, Ott P, Secher NH, Pedersen BK. Glucose ingestion attenuates the exercise-induced increase in circulating heat shock protein 72 and heat shock protein 60 in humans. Cell Stress Chaperones 9: 390–396, 2004.[CrossRef][Web of Science][Medline]
  10. Febbraio MA, Ott P, Nielsen HB, Steensberg A, Keller C, Krustrup P, Secher NH, Pedersen BK. Exercise induces hepatosplanchnic release of heat shock protein 72 in humans. J Physiol 544: 957–962, 2002.[Abstract/Free Full Text]
  11. Febbraio MA, Steensberg A, Walsh R, Koukoulas I, van Hall G, Saltin B, Pedersen BK. Reduced glycogen availability is associated with an elevation in HSP72 in contracting human skeletal muscle. J Physiol 538: 911–917, 2002.[Abstract/Free Full Text]
  12. Fehrenbach E, Niess AM, Voelker K, Northoff H, Mooren FC. Exercise intensity and duration affect blood soluble HSP72. Int J Sports Med 26: 552–557, 2005.[CrossRef][Web of Science][Medline]
  13. Fischer CP, Hiscock NJ, Basu S, Vessby B, Kallner A, Sjoberg LB, Febbraio MA, Pedersen BK. Vitamin E isoform-specific inhibition of the exercise-induced heat shock protein 72 expression in humans. J Appl Physiol 100: 1679–1687, 2006.[Abstract/Free Full Text]
  14. Flanagan SW, Ryan AJ, Gisolfi CV, Moseley PL. Tissue-specific HSP70 response in animals undergoing heat stress. Am J Physiol Regul Integr Comp Physiol 268: R28–R32, 1995.[Abstract/Free Full Text]
  15. Fleshner M, Campisi J, Amiri L, Diamond DM. Cat exposure induces both intra- and extracellular Hsp72: the role of adrenal hormones. Psychoneuroendocrinology 29: 1142–1152, 2004.[CrossRef][Web of Science][Medline]
  16. Fleshner M, Campisi J, Johnson JD. Can exercise stress facilitate innate immunity? A functional role for stress-induced extracellular Hsp72. Exerc Immunol Rev 9: 6–24, 2003.[Web of Science][Medline]
  17. Garcia-Sainz JA, Vazquez-Prado J, Villalobos-Molina R. Alpha 1-adrenoceptors: subtypes, signaling, and roles in health and disease. Arch Med Res 30: 449–458, 1999.[CrossRef][Web of Science][Medline]
  18. Goodson ML, Sarge KD. Heat-inducible DNA binding of purified heat shock transcription factor 1. J Biol Chem 270: 2447–2450, 1995.[Abstract/Free Full Text]
  19. Guzhova IV, Arnholdt AC, Darieva ZA, Kinev AV, Lasunskaia EB, Nilsson K, Bozhkov VM, Voronin AP, Margulis BA. Effects of exogenous stress protein 70 on the functional properties of human promonocytes through binding to cell surface and internalization. Cell Stress Chaperones 3: 67–77, 1998.[CrossRef][Web of Science][Medline]
  20. Hamilton KL, Powers SK, Sugiura T, Kim S, Lennon S, Tumer N, Mehta JL. Short-term exercise training can improve myocardial tolerance to I/R without elevation in heat shock proteins. Am J Physiol Heart Circ Physiol 281: H1346–H1352, 2001.[Abstract/Free Full Text]
  21. Hightower LE, Guidon PT Jr. Selective release from cultured mammalian cells of heat-shock (stress) proteins that resemble glia-axon transfer proteins. J Cell Physiol 138: 257–266, 1989.[CrossRef][Web of Science][Medline]
  22. Hollies NRS. Psychological scaling in comfort assessment. In: Clothing Comfort, edited by Hollies NRS and Goldman RF. Ann Arbor, MI: Ann Arbor Science, 1977.
  23. Hunter-Lavin C, Davies EL, Bacelar MM, Marshall MJ, Andrew SM, Williams JH. Hsp70 release from peripheral blood mononuclear cells. Biochem Biophys Res Commun 324: 511–517, 2004.[CrossRef][Web of Science][Medline]
  24. Johnson JD, Campisi J, Sharkey CM, Kennedy SL, Nickerson M, Fleshner M. Adrenergic receptors mediate stress-induced elevations in extracellular Hsp72. J Appl Physiol 99: 1789–1795, 2005.[Abstract/Free Full Text]
  25. Lancaster GI, Febbraio MA. Exosome-dependent trafficking of HSP70: a novel secretory pathway for cellular stress proteins. J Biol Chem 280: 23349–23355, 2005.[Abstract/Free Full Text]
  26. Lancaster GI, Moller K, Nielsen B, Secher NH, Febbraio MA, Nybo L. Exercise induces the release of heat shock protein 72 from the human brain in vivo. Cell Stress Chaperones 9: 276–280, 2004.[CrossRef][Web of Science][Medline]
  27. Locke M. The cellular stress response to exercise: role of stress proteins. Exerc Sport Sci Rev 25: 105–136, 1997.[Medline]
  28. Marshall HC, Ferguson RA, Nimmo MA. Human resting extracellular heat shock protein 72 concentration decreases during the initial adaptation to exercise in a hot, humid environment. Cell Stress Chaperones 11: 129–134, 2006.[CrossRef][Web of Science][Medline]
  29. Matz JM, LaVoi KP, Blake MJ. Adrenergic regulation of the heat shock response in brown adipose tissue. J Pharmacol Exp Ther 277: 1751–1758, 1996.[Abstract/Free Full Text]
  30. Milne KJ, Noble EG. Exercise-induced elevation of HSP70 is intensity dependent. J Appl Physiol 93: 561–568, 2002.[Abstract/Free Full Text]
  31. Moller N, Beckwith R, Butler PC, Christensen NJ, Orskov H, Alberti KG. Metabolic and hormonal responses to exogenous hyperthermia in man. Clin Endocrinol (Oxf) 30: 651–660, 1989.[Medline]
  32. Neumayr G, Pfister R, Hoertnagl H, Mitterbauer G, Getzner W, Ulmer H, Gaenzer H, Joannidis M. The effect of marathon cycling on renal function. Int J Sports Med 24: 131–137, 2003.[CrossRef][Web of Science][Medline]
  33. Novoselova TV, Margulis BA, Novoselov SS, Sapozhnikov AM, van der SJ, Cheetham ME, Guzhova IV. Treatment with extracellular HSP70/HSC70 protein can reduce polyglutamine toxicity and aggregation. J Neurochem 94: 597–606, 2005.[CrossRef][Web of Science][Medline]
  34. Oehler R, Pusch E, Zellner M, Dungel P, Hergovics N, Homoncik M, Eliasen MM, Brabec M, Roth E. Cell type-specific variations in the induction of hsp70 in human leukocytes by feverlike whole body hyperthermia. Cell Stress Chaperones 6: 306–315, 2001.[CrossRef][Web of Science][Medline]
  35. Pittet JF, Lee H, Morabito D, Howard MB, Welch WJ, Mackersie RC. Serum levels of Hsp 72 measured early after trauma correlate with survival. J Trauma 52: 611–617, 2002.[Web of Science][Medline]
  36. Prohaszka Z, Singh M, Nagy K, Kiss E, Lakos G, Duba J, Fust G. Heat shock protein 70 is a potent activator of the human complement system. Cell Stress Chaperones 7: 17–22, 2002.[CrossRef][Web of Science][Medline]
  37. Reilly T, Dowzer CN, Cable NT. The physiology of deep-water running. J Sports Sci 21: 959–972, 2003.[CrossRef][Web of Science][Medline]
  38. Rhind SG, Gannon GA, Shek PN, Brenner IK, Severs Y, Zamecnik J, Buguet A, Natale VM, Shephard RJ, Radomski MW. Contribution of exertional hyperthermia to sympathoadrenal-mediated lymphocyte subset redistribution. J Appl Physiol 87: 1178–1185, 1999.[Abstract/Free Full Text]
  39. Sawka MN, Burke LM, Eichner ER, Maughan RJ, Montain SJ, Stachenfeld NS. American College of Sports Medicine position stand. Exercise and fluid replacement. Med Sci Sports Exerc 39: 377–390, 2007.
  40. Skidmore R, Gutierrez JA, Guerriero V Jr, Kregel KC. HSP70 induction during exercise and heat stress in rats: role of internal temperature. Am J Physiol Regul Integr Comp Physiol 268: R92–R97, 1995.[Abstract/Free Full Text]
  41. Staib JL, Quindry JC, French JP, Criswell DS, Powers SK. Increased temperature, not cardiac load, activates heat shock transcription factor 1 and heat shock protein 72 expression in the heart. Am J Physiol Regul Integr Comp Physiol 292: R432–R439, 2007.[Abstract/Free Full Text]
  42. Stevens J. Applied Multivariate Statistics for the Social Sciences. Hillsdale, NJ: Erlbaum, 1986.
  43. Sun L, Chang J, Kirchhoff SR, Knowlton AA. Activation of HSF and selective increase in heat-shock proteins by acute dexamethasone treatment. Am J Physiol Heart Circ Physiol 278: H1091–H1097, 2000.[Abstract/Free Full Text]
  44. Taylor RP, Harris MB, Starnes JW. Acute exercise can improve cardioprotection without increasing heat shock protein content. Am J Physiol Heart Circ Physiol 276: H1098–H1102, 1999.[Abstract/Free Full Text]
  45. Udelsman R, Li DG, Stagg CA, Gordon CB, Kvetnansky R. Adrenergic regulation of adrenal and aortic heat shock protein. Surgery 116: 177–182, 1994.[Web of Science][Medline]
  46. Walsh RC, Koukoulas I, Garnham A, Moseley PL, Hargreaves M, Febbraio MA. Exercise increases serum Hsp72 in humans. Cell Stress Chaperones 6: 386–393, 2001.[CrossRef][Web of Science][Medline]
  47. Wang Y, Whittall T, McGowan E, Younson J, Kelly C, Bergmeier LA, Singh M, Lehner T. Identification of stimulating and inhibitory epitopes within the heat shock protein 70 molecule that modulate cytokine production and maturation of dendritic cells. J Immunol 174: 3306–3316, 2005.[Abstract/Free Full Text]
  48. Whelan SA, Hightower LE. Differential induction of glucose-regulated and heat shock proteins: effects of pH and sulfhydryl-reducing agents on chicken embryo cells. J Cell Physiol 125: 251–258, 1985.[CrossRef][Web of Science][Medline]
  49. Whitham M, Walker GJ, Bishop NC. Effect of caffeine supplementation on the extracellular heat shock protein 72 response to exercise. J Appl Physiol 101: 1222–1227, 2006.[Abstract/Free Full Text]
  50. Wisser H, Breuer H. Circadian changes of clinical chemical and endocrinological parameters. J Clin Chem Clin Biochem 19: 323–337, 1981.[Web of Science][Medline]
  51. Zhong M, Orosz A, Wu C. Direct sensing of heat and oxidation by Drosophila heat shock transcription factor. Mol Cell 2: 101–108, 1998.[CrossRef][Web of Science][Medline]




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