Effect of Lonicera japonica extract on lactation performance, antioxidant status, and endocrine and immune function in heat-stressed mid-lactation dairy cows.

Here, we examined the effects of Lonicera japonica extract (LJE) on lactation performance, antioxidant status, and endocrine and immune function in heat-stressed mid-lactation dairy cows. Twenty-four healthy Chinese Holstein mid-lactation dairy cows, all with similar milk yield (30.0 ± 1.0 kg/d), parity (2.5 ± 0.3), and days in milk (105 ± 5 d) were allocated to 4 groups using a randomized complete block design: a negative control group (without LJE supplementation; CON) and groups that received LJE at 14, 28, and 56 g/d. The experiment lasted 10 wk over a hot summer, with a pre-feeding period of 2 wk. Cows were exposed to heat stress, as the average temperature-humidity index was greater than 72. The results showed that LJE had no effect on respiration rate; however, it reduced the rectal temperature of dairy cows experiencing heat stress in both a linear and quadratic manner; the lowest (39.03°C) was recorded for the LJE-28 group, lower than the CON group. Supplementation with LJE did not affect dry matter intake, milk yield, or milk composition. The majority of biochemical parameters in serum were unaffected by supplementation with different amounts of LJE; the exception was creatinine, which was reduced quadratically. Compared with the CON group, serum triiodothyronine concentrations increased significantly in the LJE-28 group. Addition of LJE to the diet increased thyroxine concentrations quadratically; values peaked at 18.62 ng/mL in the LJE-28 group. Furthermore, supplementation with increasing amounts of LJE quadratically increased the activity of glutathione peroxidase and total antioxidant capacity in serum but decreased concentration of malondialdehyde. Although we detected no differences in the concentrations of IgA, IgM, or cytokines, dairy cows in the LJE-28 group had higher IgG and IL-4 concentrations than did cows in the CON group. Supplementation with LJE increased concentrations of IgG and IL-4 in the serum quadratically but decreased that of IL-2. Finally, heat shock protein 72 concentrations in the serum tended to fall quadratically as the amount of LJE increased. In summary, LJE had no negative effects on lactation performance but helped to alleviate heat stress by improving antioxidant status and promoting endocrine and immune functions. Supplementation with LJE at 28 g/d is recommended for lactating dairy cows experiencing heat stress during hot summers.

Dietary supplementation of brown seaweed (Sargassum latifolium) alleviates the environmental heat stress-induced toxicity in male Barki sheep (Ovis aries).

Heat stress (HS) is the most potent environmental stressors for livestock in tropical and subtropical regions. HS induced splanchnic tissue hypoxia and intestinal oxidative damage, leading to endotoxemia and systemic inflammation. The present study evaluated and compared the modulatory effects of feeding Barki male sheep (Ovis aries) on a standard concentrated diet containing 2% or 4% of the brown seaweed (Sargassum latifolium) followed by roughage for 40 consecutive days on the toxicity-induced by exposure to severe environmental HS (temperature-humidity index = 28.55 ± 1.62). The present study showed that the diet containing Sargassum latifolium (especially 4%) modulated significantly (P < 0.05-0.001) almost all changes shown in the HS-exposed sheep including the increase in the thermo-respiratory responses (skin and rectal temperatures, and respiration rate) and the resulted dyslipidemia, anemia, and systemic inflammation (blood leukocytosis, the elevation in the erythrocyte sedimentation rate, and the increase in serum proinflammatory cytokines and heat shock protein-70 concentrations). In addition, Sargassum latifolium improved significantly (P < 0.05-0.001) the body-weight gain, kidney functions (especially at the high dose), and blood antioxidant defense system (total antioxidant capacity, and the activities of catalase and superoxide dismutase) in the HS-exposed sheep, as well as protected the animals from oxidative tissue damage and the risk of atherosclerosis. In conclusion, feeding sheep with the diet containing 4% of Sargassum latifolium was safe and suitable for animal nutrition, as well as efficiently alleviated the harmful effects of the environmental HS in Barki sheep through improving the animal antioxidant defense system, and regulating the thermo-respiratory and inflammatory responses.

Perioperative urinary heat shock protein 72 as an early marker of acute kidney injury in dogs.

OBJECTIVE: Acute kidney injury (AKI) may be a complication in dogs undergoing surgery. Urinary heat shock protein 72 (uHSP72) is a sensitive biomarker of canine AKI. To assess the occurrence of perioperative AKI, based on uHSP72 compared with serum creatinine (sCr), and whether its occurrence is associated with the American Society of Anesthesiology physical status (ASA status). STUDY DESIGN: Clinical prospective study. ANIMALS: A total of 80 client-owned and shelter dogs. METHODS: Dogs scheduled for elective or emergency surgery were assigned ASA status (ASA I-IV). Preoperative and 24 hour postoperative serum and urine samples were collected. sCr, uHSP72 and urinary creatinine (uCr) were measured. RESULTS: Postoperative uHSP72/uCr concentration [median (range)] of all dogs undergoing surgery [2.40 (0.14-252) ng mg-1] was significantly increased compared with preoperative uHSP72/uCr [1.30 (0.11-142) ng mg-1] concentration (p < 0.001). Conversely, postoperative sCr concentration of all dogs [0.88 (0.3-1.6) mg dL-1] significantly decreased compared with preoperative sCr concentration [0.8 (0.2-5.0) mg dL-1; p = 0.001]. Median uHSP72/uCr concentration differed both preoperatively (p = 0.007) and postoperatively (p = 0.019) among the ASA status groups. Increased uHSP/uCr was measured in 20 dogs preoperatively and 33 dogs postoperatively, whereas only five dogs fulfilled the criteria of AKI based on sCr. CONCLUSIONS: The occurrence of increased uHSP72/uCr perioperatively suggests that the proportion of dogs with AKI is considerably higher than perceived. CLINICAL RELEVANCE: Dogs undergoing surgery should be closely monitored for AKI before and after anesthesia, using currently available markers (e.g., sCr) and more sensitive markers.

Effects of severe whole-body hyperthermia on ovarian hormone and extracellular Hsp72 responses in young adult women.

Background: Although acute thermal stress appears to be one of the most effective stressors that increase the intra- and extracellular concentrations of heat shock protein 72 (Hsp72), 17ß-estradiol has been shown to inhibit heat-induced Hsp72 expression. Materials and Methods: To determine whether severe whole-body hyperthermia (increase in rectal temperature up to 39.5 °C) induced by lower-body heating is a sufficient stimulus to modulate hormonal (17ß-estradiol, progesterone, prolactin, epinephrine, and norepinephrine) and extracellular Hsp72 responses, we investigated young adult women (21 ± 1 yr). Results and Conclusions: In the present study, we show that a severe whole-body hyperthermia (increase in rectal temperature of approximately 2.6 °C and heart rate of approximately 80 bpm from baseline) was sufficient to increase 17ß-estradiol, progesterone, and prolactin and catecholamine norepinephrine concentration. Moreover, we show that the concentration of extracellular Hsp72 and catecholamine epinephrine were not affected by severe whole-body hyperthermia in young adult women. From the functional point of view, expression of ovarian hormones induced by passive heat stress may have therapeutic potential for young adult women in, for example, estrogen treatment and overall women's health.

Effects of eccentric exercise on different slopes.

OBJECTIVES: Eccentric contraction occurs when the muscle lengthens under tension. Damage-induced responses seen in the muscle after eccentric exercise usually experienced by sedentary individuals. This study aims to investigate muscle damage on different slopes. METHODS: 32 male Wistar albino rats randomly divided into four groups: sedentary, horizontal running, and eccentric exercise (-8°, -16°) groups. Animals ran for 90 min with the speed of 25 m/s for five days. After 48h from the last exercise, rats were sacrificed, and plasma creatine kinase (CK), heat shock protein 70 (HSP70) levels were examined. Plasma and soleus total oxidant/antioxidant status (TOS-TAS) and histological changes of soleus muscle assessed. RESULTS: CK and HSP70 significantly increased in 16° EE group. TOS increased at 16° EE and 8° EE, but oxidative stress index (OSI) was only high at 8° EE group. Mononuclear cell infiltration and the angiogenesis increased in soleus after eccentric exercise, and there was a correlation with slope. Sarcomere breaks were detected in 16° EE group also in a correlation with slope. CONCLUSIONS: Consequently, sedentary individuals are vulnerable to injuries induced by eccentric contraction. Therefore, our study provides information for reconsidering rehabilitation and training programs.

The inflammatory response to a wheelchair half-marathon in people with a spinal cord injury - the role of autonomic function.

This study investigates the relationship between autonomic function and the inflammatory response to a wheelchair half-marathon in people with a spinal cord injury (SCI). Seventeen wheelchair athletes with a cervical SCI (CSCI, N = 7) and without CSCI (NON-CSCI, N = 10) participated in a wheelchair half-marathon. Blood was taken prior, post and 1 h post-race to determine the concentrations of adrenaline, noradrenaline, extracellular heat shock protein 72 (eHsp72) and interleukin-6 (IL-6). A sit-up tilt test was performed to assess autonomic function at rest. CSCI showed a lower supine ratio of the low and high frequency power of the variability in RR intervals (LF/HF RRI, p = 0.038), total and low frequency power of the systolic blood pressure variability (TP SBP, p < 0.001; LF SBP, p = 0.005) compared to NON-CSCI. Following the race, catecholamine concentrations increased only in NON-CSCI (p < 0.036). The increase in IL-6 post-race was larger in NON-CSCI (p = 0.040). Post-race catecholamine levels explained 60% of the variance in the IL-6 response (r = 0.77, p = 0.040), which was further increased when the resting autonomic function indices were added to the regression model (R2 > 81%, p < 0.012). In summary, the dampened acute inflammatory response to a wheelchair half-marathon in CSCI was strongly associated with the autonomic dysfunction present in this group.

Dietary curcumin supplementation does not alter peripheral blood mononuclear cell responses to exertional heat stress.

INTRODUCTION: Curcumin reduces gut barrier damage and plasma cytokine responses to exertional heat stress. However, the role of peripheral blood mononuclear cell (PBMC) in this response remains unclear. PURPOSE: This work investigated the effect of 3 days of 500 mg/day dietary curcumin supplementation on PBMC responses to exertional heat stress in non-heat acclimated humans. METHODS: Eight participants ran (65% VO2max) for 60 min in an environmental chamber (37 °C/25% RH) two times (curcumin/placebo). Blood samples were collected pre, post, 1 h post, and 4 h post-exercise. PBMC were isolated from blood samples and the protein content of markers along the TLR4 signaling pathway (TLR4, MyD88, pNF-κB, NF-κB), indicators of cellular energy status (SIRT1 and p-AMPK), and mediators of cellular heat shock response (pHSF-1 and HSP70) were examined with Western blot. Data were analyzed with two-way (condition × time) RM-ANOVAs with Newman-Keuls post hocs. RESULTS: As compared to placebo, curcumin did not alter protein expression in PBMC (p > 0.05). However, in both study conditions at 1 h post-reductions were noted in TLR 4 (- 21.5%; p = 0.03), HSP70 (- 11.0%; p = 0.04), pAMPK (- 48.5%; p < 0.01), and SIRT1 (- 47.8%; p < 0.01). Remarkably, the ratio of pNF-κB to NF-κB was elevated in both conditions at this same timepoint (+ 75.4%; p = 0.02). CONCLUSIONS: Inflammatory protein expression in PBMC did not differ between curcumin and placebo conditions. Downregulation of pAMPK/SIRT1 and release of HSP70 to the bloodstream may compensate for reduced TLR4, allowing PBMC to maintain inflammatory capacity and preventing an "open window" during the hours following hyperthermic exercise.

Whole body precooling attenuates the extracellular HSP72, IL-6 and IL-10 responses after an acute bout of running in the heat.

The impact of whole-body precooling on the extracellular heat shock protein 72 (eHSP72) and cytokine responses to running in the heat is undefined. The aim of this study was to determine whether precooling would attenuate post-exercise eHSP72 and cytokine responses. Eight male recreational runners completed two 90-minute bouts of running at 65% [Formula: see text]O2max in 32 ± 0.9°C and 47 ± 6 % relative humidity (RH) preceded by either 60-minutes of precooling in 20.3 ± 0.3°C water (COOL) or 60 min rest in an air-conditioned laboratory (20.2 ± 1.7°C, 60 ± 3% RH; CON). eHSP72, TNF-α, IL-6, IL-10 IL-1ra were determined before and immediately after exercise. The elevation in post-exercise eHSP72 was attenuated after COOL (+0.04 ± 0.10 ng.mL-1) compared to CON (+ 0.29 ± 0.26 ng.mL-1;P < 0.001). No changes in TNF-α were observed at any stage. COOL reduced the absolute post-exercise change in IL-6 (P = 0.011) and IL-10 (P = 0.03) compared to CON. IL-1ra followed this trend (P = 0.063). A precooling-induced attenuation of eHSP72 and proinflammatory cytokines may aid recovery during multi-day sporting events, but could be counterproductive if a training response or adaptation to environmental stress is a desired outcome.

Effect of low-intensity resistance training with heat stress on the HSP72, anabolic hormones, muscle size, and strength in elderly women.

BACKGROUND: Several recent studies have reported that heat stress stimulates the activation of heat shock protein 72 (HSP72), leading to an increase in muscle synthesis. Some studies suggested that low-intensity resistance training combined with heat stress could improve muscle size and strength. AIM: This study aimed to identify the effect of low-intensity resistance training with heat stress over 12 weeks on the HSP72, anabolic hormones, muscle size, and strength in elderly women. METHODS: The subjects were physically healthy women of 65-75 years, who were randomly assigned to one of three groups: a low-intensity resistance training with heating sheet group (HRT group, n = 8), a moderate-intensity resistance training (RT group, n = 6), and a heating sheet group (HEAT group, n = 7). Computed tomography scans, 1-repetition maximum (1RM), and blood samples were taken pre- and post-training. RESULTS: The HSP72 did not vary significantly between the different groups and times. The IGF-1 and 1RM had significantly increased in all three groups after the training (respectively, p < 0.05). Moreover, the cross-sectional area (CSA) of the quadriceps showed a significantly greater increase in the HRT group than in the HEAT group (p < 0.05). CONCLUSIONS: We found that low-intensity training with heat stress stimulated the anabolic hormones of elderly women, improving their muscle strength and hypertrophy. We believe that low-intensity training with heat stress is an effective way to prevent muscle atrophy and to improve muscle strength in elderly women.

Anti-inflammatory effect as a mechanism of effectiveness underlying the clinical benefits of pelotherapy in osteoarthritis patients: regulation of the altered inflammatory and stress feedback response.

The purpose of the present investigation was to evaluate whether an anti-inflammatory effect together with an improvement of the regulation of the interaction between the inflammatory and stress responses underlies the clinical benefits of pelotherapy in osteoarthritis (OA) patients. This study evaluated the effects of a 10-day cycle of pelotherapy at the spa centre 'El Raposo' (Spain) in a group of 21 OA patients diagnosed with primary knee OA. Clinical assessments included pain intensity using a visual analog scale; pain, stiffness and physical function using the Western Ontario and McMaster Universities Arthritis Index; and health-related quality of life using the EuroQol-5D questionnaire. Serum inflammatory cytokine levels (IL-1ß, TNF-α, IL-8, IL-6, IL-10 and TGF-ß) were evaluated using the Bio-Plex® Luminex® system. Circulating neuroendocrine-stress biomarkers, such as cortisol and extracellular 72 kDa heat shock protein (eHsp72), were measured by ELISA. After the cycle of mud therapy, OA patients improved the knee flexion angle and OA-related pain, stiffness and physical function, and they reported a better health-related quality of life. Serum concentrations of IL-1ß, TNF-α, IL-8, IL-6 and TGF-ß, as well as eHsp72, were markedly decreased. Besides, systemic levels of cortisol increased significantly. These results confirm that the clinical benefits of mud therapy may well be mediated, at least in part, by its systemic anti-inflammatory effects and neuroendocrine-immune regulation in OA patients. Thus, mud therapy could be an effective alternative treatment in the management of OA.

Short-term reliability of inflammatory mediators and response to exercise in the heat.

Prospective application of serum cytokines, lipopolysaccharide (LPS), and heat shock proteins (eHSPs) requires reliable measurement of these biomarkers that can signify exercise-induced heat stress in hot conditions. To accomplish this, both short-term (7 day) reliability (at rest, n = 12) and the acute responsiveness of each biomarker to exercise in the heat (pre and post 60-min cycling, 34.5°C and 70% RH, n = 20) were evaluated. Serum was analysed for the concentration of C-reactive protein (CRP), interleukin-6 (IL-6), heat shock protein 72 (eHSP72), immunoglobulin M (IgM) and LPS. Test-retest reliability was determined as the coefficient of variation (CV). Biomarkers with the least short-term within-participant variation were IL-6 (19%, ±20%; CV, ±95% confidence limits (CL)) and LPS (23%, ±13%). Greater variability was observed for IgM, eHSP72 and CRP (CV range 28-38%). IL-6 exhibited the largest increase in response to acute exercise (95%, ±11%, P = < 0.001) and although CRP had a modest CV (12%, ±7%), it increased substantially post-exercise (P = 0.02, ES; 0.78). In contrast, eHSP72 and LPS exhibited trivial changes post-exercise. It appears variation of common inflammatory markers after exercise in the heat is not always discernible from short-term (weekly) variation.

Transgenic sickle cell trait mice do not exhibit abnormal thermoregulatory and stress responses to heat shock exposure.

There remains controversy over whether individuals with sickle cell trait (SCT) are vulnerable to health risks during physical activity in high temperatures. We examined thermoregulatory and stress-related responses to heat exposure in SCT and wild-type (WT) mice. No significant differences in core temperature (Tc) were observed between SCT and WT mice during heat exposure. There was no correlation between peak Tc during heat exposure and levels of hemoglobin S in SCT mice. Basal levels of circulating inflammatory and stress-related markers were not significantly different between SCT and WT mice. Although heat exposure caused significant increases in plasma interleukins 1ß and 6, and 8-isoprostane in SCT and WT mice, no differences were found between SCT and WT mice with similar thermal response profiles during heat exposure. SCT mice had significantly higher expression of heat shock protein 72 in heart, liver and gastrocnemius muscle than WT mice under control and post-heat conditions. In conclusion, there is neither thermoregulatory dysfunction nor abnormal stress-related response in SCT mice exposed to moderate heat. The hemoglobin variant in mice is associated with altered tissue stress protein homeostasis.

Sixteen weeks of resistance training decrease plasma heat shock protein 72 (eHSP72) and increase muscle mass without affecting high sensitivity inflammatory markers' levels in sarcopenic men.

BACKGROUND: Sarcopenia has been associated with increased systemic inflammation and risk of physical disability in older adults. Recently, extracellular heat shock protein 72 (eHSP72) was proposed as a biomarker of sarcopenia but its response to interventions designed to increase muscle mass has never been evaluated. AIMS: The present study was designed to (1) assess eHSP72 levels following resistance training and, (2) determine whether changes in eHSP72 correlate to changes in muscle mass and inflammatory markers. METHODS: A total of 26 sarcopenic men participated in a 16-week resistance training program. The following variables were measured pre-post-intervention: plasma HSP72, serum high sensitivity (hs) inflammatory markers: interleukin-6 (hsIL-6), C-reactive protein (hsCRP), and tumor necrosis factor alpha (hsTNF-α), lean body mass (LBM) and appendicular muscle mass index (appMMI). RESULTS: eHSP72 was detected in 47 % of our participants and its level significantly decreased (P = 0.04) after the intervention, with a concomitant increase in several LBM variables and appMMI (all P < 0.035). Serum hsIL-6, hsCRP and hsTNF-α changes did not reach significance. Baseline hsIL-6 and hsCRP levels were negatively correlated with several LBM variables but solely baseline hsIL-6 was associated with changes in appLBM. No correlations were found between changes in measured variables. DISCUSSION: Attenuation of eHSP72 following resistance training in parallel with increase in LBM variables showed a concordance between the evolution of this biomarker and a clinical outcome relevant to sarcopenia. CONCLUSION: Nevertheless, the low bloodstream detection rate of eHSP72 in a sarcopenic otherwise healthy population might limit its use in clinical settings for now.

Effective microorganism - X attenuates circulating superoxide dismutase following an acute bout of intermittent running in hot, humid conditions.

This study determined the effectiveness of antioxidant supplementation on high-intensity exercise-heat stress. Six males completed a high-intensity running protocol twice in temperate conditions (TEMP; 20.4°C), and twice in hot conditions (HOT; 34.7°C). Trials were completed following7 days supplementation with 70 ml·day(-1) effective microorganism-X (EM-X; TEMPEMX or HOTEMX) or placebo (TEMPPLA or HOTPLA). Plasma extracellular Hsp72 (eHsp72) and superoxide dismutase (SOD) were measured by ELISA. eHsp72 and SOD increased pre-post exercise (p < 0.001), with greater eHsp72 (p < 0.001) increases observed in HOT (+1.5 ng·ml(-1)) compared to TEMP (+0.8 ng·ml(-1)). EM-X did not influence eHsp72 (p > 0.05). Greater (p < 0.001) SOD increases were observed in HOT (+0.22 U·ml(-1)) versus TEMP (+0.10 U·ml(-1)) with SOD reduced in HOTEMX versus HOTPLA (p = 0.001). Physiological and perceptual responses were all greater (p < 0.001) in HOT versus TEMP conditions, with no difference followed EM-X (p > 0.05). EM-X supplementation attenuated the SOD increases following HOT, potentiating its application as an ergogenic aid to ameliorate oxidative stress.

Isothermic and fixed-intensity heat acclimation methods elicit equal increases in Hsp72 mRNA.

Thermotolerance, to which heat shock protein-72 (Hsp72) contributes, is an acquired state achieved following heat acclimation (HA), eliciting cellular adaption and protection against thermal stress. Optimal HA methods achieving the greatest heat shock response (HSR) are equivocal; therefore, investigation of methods provoking the greatest sustained HSR is required to optimize cellular adaptation. Twenty-four males performed short-term HA (STHA; five sessions) and long-term HA (LTHA; STHA plus further five sessions) utilizing fixed-intensity (FIXED; workload = 50% V ˙ O 2 p e a k ), continuous isothermic HA [ISOCONT ; target rectal temperature (Trec ) = 38.5 °C], or progressive isothermic HA (ISOPROG ; target Trec = 38.5 °C for STHA then target Trec = 39.0 °C for LTHA). Leukocyte Hsp72 mRNA was measured pre- and post day 1, day 5, and day 10 of HA via reverse transcription quantitative polymerase chain reaction to determine the HSR. Hsp72 mRNA increased (P < 0.05) pre- to post day 1, pre- to post day 5, and pre to post day 10 in FIXED, ISOCONT , and ISOPROG , but no differences were observed between methods (P > 0.05). The equal Hsp72 mRNA increases occurring from consistent, reduced, or increased endogenous strain following STHA and LTHA suggest that transcription occurs following attainment of sufficient endogenous criteria. These data give confidence that all reported HA methods increase Hsp72 mRNA and are capable of eliciting adaptations toward thermotolerance.

Elevated levels of extracellular heat-shock protein 72 (eHSP72) are positively correlated with insulin resistance in vivo and cause pancreatic ß-cell dysfunction and death in vitro.

eHSP72 (extracellular heat-shock protein 72) is increased in the plasma of both types of diabetes and is positively correlated with inflammatory markers. Since aging is associated with a low-grade inflammation and IR (insulin resistance), we aimed to: (i) analyse the concentration of eHSP72 in elderly people and determine correlation with insulin resistance, and (ii) determine the effects of eHSP72 on ß-cell function and viability in human and rodent pancreatic ß-cells. Fasting blood samples were collected from 50 older people [27 females and 23 males; 63.4±4.4 years of age; BMI (body mass index)=25.5±2.7 kg/m2]. Plasma samples were analysed for eHSP72, insulin, TNF (tumour necrosis factor)-α, leptin, adiponectin and cortisol, and glycaemic and lipid profile. In vitro studies were conducted using rodent islets and clonal rat and human pancreatic ß-cell lines (BRIN-BD11 and 1.1B4 respectively). Cells/islets were incubated for 24 h with eHSP72 (0, 0.2, 4, 8 and 40 ng/ml). Cell viability was measured using three different methods. The impact of HSP72 on ß-cell metabolic status was determined using Seahorse Bioscience XFe96 technology. To assess whether the effects of eHSP72 were mediated by Toll-like receptors (TLR2/TLR4), we co-incubated rodent islets with eHSP72 and the TLR2/TLR4 inhibitor OxPAPC (oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine; 30 µg/ml). We found a positive correlation between plasma eHSP72 and HOMA-IR (homoeostasis model assessment of IR) (r=0.528, P<0.001), TNF-α (r=0.389, P<0.014), cortisol (r=0.348, P<0.03) and leptin/adiponectin (r=0.334, P<0.03). In the in vitro studies, insulin secretion was decreased in an eHSP72 dose-dependent manner in BRIN-BD11 cells (from 257.7±33 to 84.1±10.2 µg/mg of protein per 24 h with 40 ng/ml eHSP72), and in islets in the presence of 40 ng/ml eHSP72 (from 0.48±0.07 to 0.33±0.009 µg/20 islets per 24 h). Similarly, eHSP72 reduced ß-cell viability (at least 30% for BRIN-BD11 and 10% for 1.1B4 cells). Bioenergetic studies revealed that eHSP72 altered pancreatic ß-cell metabolism. OxPAPC restored insulin secretion in islets incubated with 40 ng/ml eHSP72. In conclusion, we have demonstrated a positive correlation between eHSP72 and IR. In addition, we suggest that chronic eHSP72 exposure may mediate ß-cell failure.

Plasma and lymphocyte Hsp72 responses to exercise in athletes with prior exertional heat illness.

We investigated the effect of exercise in the heat on both intracellular and extracellular Hsp72 in athletes with a prior history of exertional heat illness (EHI). Two groups of runners, one consisting of athletes who had a previous history of EHI, and a control group (CON) of similar age (29.7 ± 1.2 and 29.1 ± 2 years CON vs. EHI) and fitness [maximal oxygen consumption [Formula: see text] 65.7 ± 2 and 64.5 ± 3 ml kg(-1) min(-1) CON vs. EHI] were recruited. Seven subjects in each group ran on a treadmill for 1 h at 72 % [Formula: see text] in warm conditions (30 °C, 40 % RH) reaching rectal temperatures of ~39.3 (CON) and ~39.2 °C (EHI). Blood was collected every 10 min during exercise and plasma was analysed for extracellular Hsp72. Intracellular Hsp72 levels were measured in both monocytes and lymphocytes before and immediately after the 60-min run, and then after 1 h recovery at an ambient temperature of 24 °C. Plasma Hsp72 increased from 1.18 ± 0.14 and 0.86 ± 0.08 ng/ml (CON vs. EHI) at rest to 4.56 ± 0.63 and 4.04 ± 0.45 ng/ml (CON vs. EHI, respectively) at the end of exercise (p < 0.001), with no difference between groups. Lymphocyte Hsp72 was lower in the EHI group at 60 min of exercise (p < 0.05), while monocyte Hsp72 was not different between groups. The results of the present study suggest that the plasma Hsp72 response to exercise in athletes with a prior history of EHI remained similar to that of the CON group, while the lymphocyte Hsp72 response was reduced.

Short-term but not long-term hypoglycaemia enhances plasma levels and hepatic expression of HSP72 in insulin-treated rats: an effect associated with increased IL-6 levels but not with IL-10 or TNF-α.

The inducible expression of the 70-kDa heat shock proteins (HSP70) is associated with homeostatically stressful situations. Stresses involving sympathetic nervous system (SNS) activation, including α1-adrenergic agonists and physical exercise, are capable of inducing HSP70 expression and release of the HSP70 inducible form, HSP72. However, whether hypoglycaemia is capable of influencing HSP70 status under a stressful situation such as insulin-induced hypoglycaemia (IIH), which also involves SNS activation, is unsettled. Hence, we decided to investigate whether the predominant signal for HSP70 expression and delivery into the blood comes from either low glucose, high insulin, or both during short-term IIH (STIIH) and long-term IIH (LTIIH). Our data indicated that low glucose level (up to 1.56 ± 0.14 mM), but not insulin, is the triggering factor responsible for a dramatic rise in HSP72 plasma concentrations (from 0.15 ± 0.01 in fed state to 0.77 ± 0.13 ng/mL during hypoglycaemic episodes). This was observed in parallel with up to 7-fold increases in interleukin-6 (IL-6) but not interleukin-10 (IL-10) or tumour necrosis factor-α (TNF-α) at STIIH. Together, the observations may suggest that HSP72 is released under hypoglycaemic conditions as a part of the homeostatic stress response, whereas at long-term, both hypoglycaemia and insulin may influence HSP72 expression in the liver, but not in kidneys. Secreted extracellular HSP72 (eHSP72) may be purely a danger signal to all the tissues of the body for the enhancement of immune and metabolic surveillance state or actively participates in glycaemic control under stressful situations.

Combined activity of post-exercise concentrations of NA and eHsp72 on human neutrophil function: role of cAMP.

Extracellular heat shock proteins of 72 kDa (eHsp72) and noradrenaline (NA) can act as "danger signals" during exercise-induced stress by activating neutrophil function (chemotaxis, phagocytosis, and fungicidal capacity). In addition, post-exercise concentrations of NA increase the expression and release of Hsp72 by human neutrophils, and adrenoreceptors and cAMP are involved in the stimulation of neutrophils by eHsp72. This suggests an interaction between the two molecules in the modulation of neutrophils during exercise-induced stress. Given this context, the aim of the present investigation was to study the combined activity of post-exercise circulating concentrations of NA and eHsp72 on the neutrophil phagocytic process, and to evaluate the role of cAMP as intracellular signal in these effects. Results showed an accumulative stimulation of chemotaxis induced by NA and eHsp72. However, while NA and eHsp72, separately, stimulate the phagocytosis and fungicidal activity of neutrophils, when they act together they do not modify these capacities of neutrophils. Similarly, post-exercise concentrations of NA and eHsp72 separately increased the intracellular level of cAMP, but NA and eHsp72 acting together did not modify the intracellular concentration of cAMP. These results confirm that cAMP can be involved in the autocrine/paracrine physiological regulation of phagocytosis and fungicidal capacity of human neutrophils mediated by NA and eHsp72 in the context of exercise-induced stress.

The inflammasome and danger associated molecular patterns (DAMPs) are implicated in cytokine and chemokine responses following stressor exposure.

Exposure to stressors or trauma in the absence of pathogenic challenge can stimulate a systemic sterile inflammatory response characterized by high concentrations of blood and tissue cytokines, chemokines, and danger associated molecular patterns (DAMPs) such as heat shock protein-72 (Hsp72), and uric acid. The signaling pathways responsible for these responses remain unclear, however, the inflammasome may play a role. In vitro, DAMPs are known to stimulate the inflammasome in the presence of LPS to activate caspase-1 which cleaves immature precursors of interleukin (IL)-1ß and IL-18 into their mature releasable forms. Furthermore, in vivo neutralization of the LPS selectively attenuates the stress-induced increase in the inflammasome-dependent cytokines IL-1ß and IL-18. Thus, the current experiments tested the hypothesis that inflammasome-mediated processes are necessary for a systemic stress-induced inflammatory response to an acute stressor. The data presented (1) establish that male F344 rats exposed to an acute severe stressor (100 tail shocks) have elevated plasma concentrations of inflammatory proteins (IL-1ß, IL-18, IL-6, IL-10, and monocyte chemotactic protein (MCP)-1), and DAMPs (uric acid and Hsp72); (2) demonstrate that inhibiting caspase-1 in vivo, using the caspase-1 inhibitor ac-YVAD-cmk, attenuates stress-induced production of IL-1ß, IL-18, and IL-6 in both the circulation and peripheral tissues; and (3) implicates the DAMPs uric acid and Hsp72 as important signals contributing to inflammasome-dependent inflammatory responses using a stepwise multiple regression. The results increase our mechanistic understanding of systemic sterile inflammatory responses, and provide novel evidence that the inflammasome may be an important pharmacological target for treatment of these conditions.