Extracellular histones exacerbate heat stroke-induced liver injury by triggering hepatocyte pyroptosis and liver injury via the TLR9-NLRP3 pathway.

BACKGROUND: Severe heat stroke is often complicated by multiple organ failure, including liver injury. Recent evidence indicates that the underlying mechanism constitutes sterile inflammation triggered by cell damage, in which hepatocyte NOD-like receptor family pyrin domain-containing 3 inflammasome activation and pyroptosis play key roles. As extracellular histones act as damage-associated molecular patterns and mediate tissue toxicity and inflammation, we aimed to investigate whether extracellular histones contribute to inducing hepatocyte pyroptosis following heat stroke, promoting the development of liver inflammation and injury, and elucidate the potential underlying mechanisms. METHODS: Exogenous histones were administered to AML-12 murine hepatocytes or male aged 8-12 week mice following hyperthermic treatment (at 39 °C in a chamber with 60 % relative humidity). Prior to heat exposure, endogenous histones were neutralized using neutralizing antibodies, inflammasomes were inhibited by RNA silencing, and Toll-like receptor 9 was modulated using a pharmacological agonist or antagonist. Inflammasome assembly, caspase-1 activation, histological changes, and liver enzyme levels were measured. Statistical comparison of more than two groups was performed using one-way ANOVA with Tukey's post-hoc testing. The correlations were analyzed using Pearson's correlation test. All experiments were repeated thrice. A p-value < 0.05 was considered significant. RESULTS: Heat stroke induced histone release into the extracellular space at levels correlating with liver injury. Moreover, extracellular histones augmented heat stroke-induced liver injury both in vitro and in vivo in a dose- and time-dependent manner, whereas neutralizing histones conferred protection following heat stroke. Histones mediated NOD-like receptor family pyrin domain-containing 3 inflammasome activation through the Toll-like receptor 9 signaling pathway, which resulted in hepatocyte pyroptosis and liver inflammation. CONCLUSIONS: Our findings show that histones are critical mediators of hepatocyte pyroptosis that aggravate liver injury in a heat stroke setting. Therefore, we suggest extracellular histones as potential therapeutic targets to limit heat stroke-induced cell death and liver injury.

Proteomic profiling of serum exosomes reveals acute phase response and promotion of inflammatory and platelet activation pathways in patients with heat stroke.

Background: The pathological mechanism of heat stroke (HS) involves the acute phase response, unbalanced immunological/inflammatory reactions, and coagulation initiation, especially platelet activation. Although exosomes contain proteins involved in these biological processes, their protein cargo levels and potential roles in HS remain unknown. This study explored the serum exosome protein expression patterns after HS and their potential roles in the pathogenesis of HS. Methods: Blood samples were collected from ten patients diagnosed with HS upon admission to the intensive care unit (six with severe HS and four with mild HS). Samples from six healthy volunteers were included as control. Using ultracentrifugation, exosomes were prudently isolated, and their protein contents were profiled using liquid chromatography-tandem mass spectrometry analysis with isobaric tags for relative and absolute quantification-based proteomics. Results: Compared with healthy volunteers, patients with HS showed significant changes in the levels of 33 exosomal proteins (23 upregulated and 10 downregulated). The most upregulated proteins included serum amyloid A-1 (SAA-1), von Willebrand factor (vWF), S100A8, and histone H3. In addition, SAA-1, vWF, platelet membrane glycoprotein, S100A8, and histone H3 were more enriched in the exosomes from patients with severe HS than from those with mild HS. Gene ontology analysis revealed that the HS-modulated exosomal proteins were mostly related to inflammatory response, including the acute-phase response, platelet activation/degranulation, and innate immune response. Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed significant enrichment of proteins in the IL-17 signaling pathway, platelet activation, neutrophil extracellular trap formation, Fc epsilon RI signaling pathway, chemokine signaling pathway, and NOD-like receptor signaling pathway, among others. Several serum exosomal proteins, including SAA-1, vWF, and S100A8, which are related to the acute phase, inflammatory response, and platelet activation, were confirmed to be elevated in patients with HS, and were significantly correlated with disease severity, organ dysfunction, and death. Conclusion: Overall, this study explores the potential role of the serum exosomal proteome in the inflammatory response and platelet activation in HS, suggests the pathological mechanisms underlying HS-induced injuries, and recommends reliable exosomal biomarkers for predicting HS prognosis.

A nomogramic model for predicting the left ventricular ejection fraction of STEMI patients after thrombolysis-transfer PCI.

Background: The prognosis of ST-segment elevation myocardial infarction (STEMI) is closely linked to left ventricular ejection fraction (LVEF). In contrast to primary percutaneous coronary intervention (PPCI), thrombolysis-transfer PCI (TTPCI) is influenced by multiple factors that lead to heterogeneity in cardiac function and prognosis. The aim of this study is to develop a nomogram model for predicting early LVEF in STEMI patients with TTPCI, based on routine indicators at admission. Method: We retrospectively reviewed data from patients diagnosed with STEMI at five network hospitals of our PCI center who performed TTPCI as door-to-balloon time (the interval between arrival at the hospital and intracoronary balloon inflation) over 120 min, from February 2018 to April 2022. Categorical variables were analyzed using Pearson χ2 tests or Fisher exact tests, while Student's t-test or Mann-Whitney U-test was used to compare continuous variables. Subsequently, independent risk factors associated with reduced LVEF one week after TTPCI were identified through comprehensive analysis by combining All-Subsets Regression with Logistic Regression. Based on these indicators, a nomogram model was developed, and validated using the area under the receiver operating characteristic (ROC) curve and the Bootstrap method. Results: A total of 288 patients were analyzed, including 60 with LVEF < 50% and 228 with LVEF ≥ 50%. The nomogram model based on six independent risk factors including age, heart rate (HR), hypertension, smoking history, Alanine aminotransferase (ALT), and Killip class, demonstrated excellent discrimination with an AUC of 0.84 (95% CI: 0.78-0.89), predicted C-index of 0.84 and curve fit of 0.713. Conclusions: The nomogram model incorporating age, HR, hypertension, smoking history, ALT and Killip class could accurately predict the early LVEF ≥ 50% probability of STEMI patients undergoing TTPCI, and enable clinicians' early evaluation of cardiac function in STEMI patients with TTPCI and early optimization of treatment.

Endothelial glycocalyx injury is involved in heatstroke-associated coagulopathy and protected by N-acetylcysteine.

Introduction: Damage to endothelial glycocalyx (EGCX) can lead to coagulation disorders in sepsis. Heat stroke (HS) resembles sepsis in many aspects; however, it is unclear whether EGCX injury is involved in its pathophysiology. The purpose of this study was to examine the relationship between the damage of EGCX and the development of coagulation disorders during HS. Methods: We retrospectively collected 159 HS patients and analyzed coagulation characteristics and prognosis of HS patients with or without disseminated intravascular coagulation (DIC). We also replicated a rat HS model and measured coagulation indexes, pulmonary capillary EGCX injury in HS rats. Finally, we evaluated the effect of the antioxidant N-acetylcysteine (NAC) on HS-initiated EGCX injury and coagulation disorders. Results: Clinical data showed that HS patients complicated with DIC had a higher risk of death than HS patients without DIC. In a rat HS model, we found that rats subjected to heat stress developed hypercoagulability and platelet activation at the core body temperature of 43°C, just before the onset of HS. At 24 h of HS, the rats showed a consumptive hypo-coagulation state. The pulmonary capillary EGCX started to shed at 0 h of HS and became more severe at 24 h of HS. Importantly, pretreatment with NAC substantially alleviated EGCX damage and reversed the hypo-coagulation state in HS rats. Mechanically, HS initiated reactive oxidative species (ROS) generation, while ROS could directly cause EGCX damage. Critically, NAC protected against EGCX injury by attenuating ROS production in heat-stressed or hydrogen peroxide (H2O2)-stimulated endothelial cells. Discussion: Our results indicate that the poor prognosis of HS patients correlates with severe coagulation disorders, coagulation abnormalities in HS rats are associated with the damage of EGCX, and NAC improves HS-induced coagulopathy, probably through its protection against EGCX injury by preventing ROS generation.

[Correlation of kidney injury and inflammatory response in rats with classic severe heatstroke].

OBJECTIVE: To investigate the temporal features of renal injury in rats with severe heat stroke (SHS) and their relationship with inflammatory response. METHODS: Fifty-six male Wistar rats were randomly divided into normal control group and SHS for 0, 2, 6, 24, 48, 72 hours group (SHS-0, 2, 6, 24, 48, 72 h groups), with 8 rats in each group. Rats were placed in an artificial climate chamber [ temperature (39.5±0.2) centigrade, humidity (60±5)% ] to induce SHS model, and the criterion for successful model reproduction was the onset of lowering peak systolic blood pressure ( SBP ). Then the rats were transferred to room temperature (23.0±0.2) centigrade after successful reproduction of the model. The rats of normal control group were kept in room temperature of (23.0±0.2) centigrade. Heart blood and renal tissue samples were harvested, and the levels of serum creatinine (SCr) and blood urea nitrogen (BUN) were determined by automatic biochemistry analyzer. The levels of myeloperoxidase (MPO), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in renal tissue specimens were determined by enzyme linked immunosorbent assay (ELISA). The changes in histopathology in kidney were observed with light microscopy, and Paller scores were used to assess the degree of renal injury. RESULTS: Compared with normal control group, the levels of SCr and BUN in serum, and MPO, TNF-α and IL-6 in the renal tissue homogenate were significantly increased in SHS-6 h group [SCr (µmol/L): 174.0±27.0 vs. 68.0±11.3, BUN (mmol/L): 12.6±2.3 vs. 4.3±1.2, MPO: (203.0±38.0)% vs. (100.0±1.4 )%, TNF-α: (121.0±16.0)% vs. (100.0±1.4 )%, IL-6: (118.0±19.0)% vs. (100.0±1.3)%, all P < 0.05], and they peaked at 24 hours [SCr (µmol/L): 489.0±96.0 vs. 68.0±11.3, BUN (mmol/L): 19.3±5.7 vs. 4.3±1.2, MPO: (511.0±41.0)% vs. (100.0±1.4)%, TNF-α: (399.0±47.0)% vs. (100.0±1.4)%, IL-6: (473.0±56.0)% vs. (100.0±1.3)%, all P < 0.01], then declined to the normal levels at 72 hours. Under light microscopy, tissue edema and necrosis of renal tubules were found, and leukocyte infiltration was found to be most profuse at 24 hours, then they returned to normal levels at 72 hours. Paller scores in SHS-6 h group were significantly higher than those of the normal control group (75.45±9.70 vs. 14.23±3.26, P < 0.01), and it peaked at 24 hours (186.00±14.25 vs. 14.23±3.26, P < 0.01), followed by a gradual lowering, back to normal level at 72 hours. CONCLUSIONS: The results suggest that progressive renal damage occurred in the rats with SHS within 24 hours, and it was accompanied with elevated levels of MPO, TNF-α and IL-6 in the kidney homogenate, suggesting that inhibition of neutrophil activation and the release of IL-6, TNF-α may protect the SHS associated renal injury.

Xuebijing injection reduces organ injuries and improves survival by attenuating inflammatory responses and endothelial injury in heatstroke mice.

BACKGROUND: The pathogenesis of heatstroke is a multi-factorial process involved with an interplay among subsequent inflammation, endothelial injury and coagulation disturbances, which makes pharmacological therapy of heatstroke a challenging problem. Xuebijing injection (XBJ), a traditional Chinese medicine used to sepsis, has been reported to suppress inflammatory responses and restore coagulation disturbances. However, little is known about the role of XBJ in heatstroke. METHODS: Mice were treated with indicated dose of XBJ before and/or after the induction of heatstroke. Serum inflammatory cytokines, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), and endothelial markers, von Willebrand Factor (vWF) and E-selectin, were measured by ELISA. Liver, kidney and heart profiles including alanine aminotransferase, aspartic aminotransferase, creatinine, blood urea nitrogen, and lactate dehydrogenase, were evaluated by UniCel DxC 800 Synchron Clinical Systems, and troponin was measured by ELISA. Coagulation profiles, including thrombin time, prothrombin time, activated partial thromboplastin time, international normalized ratio, and fibrinogen were examined by STA Compact® Hemostasis System. Jejunum injury was evaluated with H&E staining. Changes in mitochondrial structure in cardiac tissue were assesed by electron microscopy. RESULTS: Pretreatment with XBJ decreased serum pro-inflammatory cytokines including TNF-α and IL-6, as well as endothelial injury markers, vWF and E-selectin, in a dose-dependent manner in heatstroke mice. Similar protective effects were observed when XBJ was administered after, or both before and after heat insult. These protective effects lasted for over 12 h in mice receiving XBJ before and after heat insult. XBJ also improved survival rates in heatstroke mice, ameliorated liver, heart, and kidney injuries, including mitochondrial damage to the heart, and reduced coagulation disturbances. CONCLUSIONS: XBJ prevents organ injuries and improves survival in heatstroke mice by attenuating inflammatory responses and endothelial injury. XBJ may be a potentially useful in the prevention and treatment of heatstroke.

Heat stress induces apoptosis through a Ca²âº-mediated mitochondrial apoptotic pathway in human umbilical vein endothelial cells.

BACKGROUND: Heat stress can be acutely cytotoxic, and heat stress-induced apoptosis is a prominent pathological feature of heat-related illnesses, although the precise mechanisms by which heat stress triggers apoptosis are poorly defined. METHODS: The percentages of viability and cell death were assessed by WST-1 and LDH release assays. Apoptosis was assayed by DNA fragmentation and caspase activity. Expression of cleaved PARP, Apaf-1, phospho-PERK, Phospho-eIF2a, ATF4, XBP-1s, ATF6, GRP78, phospho-IP3R, RYR and SERCA was estimated by Western blot. The effect of calcium overload was determined using flow cytometric analysis with the fluorescent probe Fluo-3/AM. The generation of ROS (O2-, H2O2, NO) was labeled by confocal laser scanning microscopy images of fluorescently and flow cytometry. RESULTS: In this study, we found that heat stress in HUVEC cells activated initiators of three major unfolded protein response (UPR) signaling transduction pathways: PERK-eIF2a-ATF4, IRE1-XBP-1S and ATF6 to protect against ER stress, although activation declined over time following cessation of heat stress. Furthermore, we show that intense heat stress may induce apoptosis in HUVEC cells through the calcium-mediated mitochondrial apoptotic pathway, as indicated by elevation of cytoplasmic Ca2+, expression of Apaf-1, activation of caspase-9 and caspase-3, PARP cleavage, and ultimately nucleosomal DNA fragmentation; Reactive oxygen species (ROS) appear to act upstream in this process. In addition, we provide evidence that IP3R upregulation may promote influx of Ca2+ into the cytoplasm after heat stress. CONCLUSION: Our findings describe a novel mechanism for heat stress-induced apoptosis in HUVEC cells: following elevation of cytoplasm Ca2+, activation of the mitochondrial apoptotic pathway via the IP3R upregulation, with ROS acting as an upstream regulator of the process.

Diagnosis of overt disseminated intravascular coagulation in critically Ill adults by Sonoclot coagulation analysis.

Disseminated intravascular coagulation (DIC) diagnosis is hampered by the limited availability of reliable clinical or laboratory tests. Currently available tests are time consuming and expensive. We investigated whether coagulation and platelet function analyses using the Sonoclot system were suitable for overt DIC diagnosis in critically ill adults. This was an observational diagnostic study performed in 498 patients presenting with an underlying disorder associated with DIC. Overt DIC patients were identified according to an International Society on Thrombosis and Hemostasis (ISTH) score of >5. Coagulation and platelet parameters were analyzed using the Sonoclot system, and compared with ISTH as the gold standard. Receiver operating characteristic curves and area under the curves were used to evaluate the value of the Sonoclot parameters. There were no differences for age or gender between the groups. Significant correlations were observed between activated clotting time (ACT) and ISTH score (r = 0.7; P < 0.001), clot rate (CR) and ISTH score (r = 0.5; P < 0.001), platelet function (PF) and ISTH score (r = -0.6; P < 0.001), and PF and platelet count (r = 0.5; P < 0.001). An ACT cut-off value of 213.5 s alone or combined with CR presented good sensitivity (76.7 and 86.8 %, respectively) and specificity (96.2 and 93.3 %, respectively). Sonoclot analysis can be performed using a point-of-care device that effectively discriminates low and high ISTH scores, and that effectively predicts coagulation dysfunction in patients with overt DIC.

Ten-year retrospective analysis of multiple trauma complicated by pulmonary contusion.

BACKGROUND: This study reports a 10-year retrospective analysis of multiple trauma complicated by pulmonary contusion. The purpose of this study is to ascertain the risk factors for mortality due to trauma in patients with pulmonary contusion, the impact of various treatment options for prognosis, and the risk factors for concurrent Acute Respiratory Distress Syndrome (ARDS). METHODS: We retrospectively analyzed 252 trauma patients with lung contusion admitted to the General Hospital of Guangzhou Command from January 2000 to June 2011 by using the statistical processing system SPSS 17.0 for Windows. RESULTS: We included 252 patients in our study, including 214 males and 38 females. The average age was 37.1 ± 14.9 years. There were 110 cases admitted to the ICU, of which 26 cases with ARDS. Nine of the 252 patients died. We compared those who survived with those who died by gender and age, the difference was not statistically significant (P = 0.199, P = 0.200). Separate univariate analysis of those who died and those who survived found that shock on admission (P = 0.000), coagulation disorders (P = 0.000), gastrointestinal bleeding (P = 0.02), the need for emergency surgery on admission (P = 0.000), pre-hospital intubation (P = 0.000), blood transfusion within 24 hours (P = 0.006), the use of mechanical ventilation (P = 0.000), and concurrent ARDS (P = 0.000) are poor prognosis risk factors. Further logistic analysis, including the admission GCS score (OR = 0.708, 95% CI 0.516-0.971, P = 0.032), ISS score (OR 1.135, 95% CI 1.006-1.280, P = 0.039), and concurrent ARDS (OR = 15.814, 95% CI 1.819-137.480, P = 0.012), identified the GCS score, ISS score and concurrent ARDS as independent risk factors of poor prognosis. Shock (OR = 9.121, 95% CI 0.857-97.060, P = 0.067) was also related to poor prognosis. Patients with injury factors such as road accident, falling injury, blunt injury and crush injury, et al.(P = 0.039), infection (P = 0.005), shock (P = 0.004), coagulation disorders (P = 0.006), emergency surgery (P = 0.01), pre-hospital intubation (P = 0.000), chest tube insertion (P = 0.004), blood transfusion (P = 0.000), usage of hormones (P = 0.002), phlegm (P = 0.000), ventilation (P = 0.000) were at a significantly increased risk for ARDS complications. CONCLUSIONS: Those patients with multiple trauma and pulmonary contusion admitted to the hospital with shock, coagulopathy, a need for emergency surgery, pre-hospital intubation, and a need for mechanical ventilation could have a significantly increased risk of mortality and ARDS incidence. A risk for poor prognosis was associated with gastrointestinal bleeding. A high ISS score, high APACHE2, and low GCS score were independent risk factors for poor prognosis. If patients developed an infection or were given drainage, hormones, and phlegm treatment, they were at higher risk of ARDS. Pre-hospital intubation and drainage were independent risk factors for ARDS. In patients with ARDS, the ICU stay, total length of stay, and hospital costs might increase significantly. A GCS score < 5.5, APACHE 2 score > 16.5, and ISS score > 20.5 could be considered indicators of poor prognosis for patients with multiple trauma and lung contusion.

Vascular endothelial cell injury partly induced by mesenteric lymph in heat stroke.

Animal models have shown that mesenteric lymph plays important roles in the pathogenesis of endothelium injury in many critical ill states. Gut-derived septicemia and endothelium injury are the two key pathogenesis of heat stroke (HS); however, it is unclear whether mesenteric lymph is cytotoxic to endothelium in HS. HS rat models were prepared in a prewarmed incubator. Mesenteric lymph, collected pre-, during, and post-HS, was analyzed for biological activity on human umbilical vein endothelial cell (HUVEC) in vitro. The effect of HS lymph on the production of von Willebrand factor (vWF), thrombomodulin (TM), and IL-6 by HUVEC was investigated. In vivo, vascular endothelium injury biomarkers, circulating endothelial cell (CEC), as well as serum soluble vWF and TM were tested in rats of HS and HS with mesenteric lymph duct ligation (HS-LDL). HS but not heat stroke sham mesenteric lymph-injured endothelial cells showed significantly increased HUVEC cytotoxicity and enhanced HUVEC monolayer permeability as well as elevated levels of vWF and TM production by HUVEC. IL-6 production by HUVEC was augmented by HS lymph in vitro. The effects of HS lymph on IL-6 production had a time course resembling that of the toxic effects of HS lymph on HUVEC. In vivo, when compared with HS rats, decreased CEC counts as well as lower serum vWF and TM concentrations were detected in HS-LDL rats. HS mesenteric lymph is probably harmful to vascular endothelium, which indicates that the modulation of mesenteric lymph may have some potential benefits to HS.

HMGB1 activity inhibition alleviating liver injury in heatstroke.

BACKGROUND: Heatstroke is generally considered as a sepsis-like syndrome induced by hyperthermia leading to multiorgan dysfunction. High-mobility group box 1 (HMGB1) has recently been identified as a mediator of systemic inflammation leading to multiorgan dysfunction in sepsis and nonsepsis. Elevation of plasma HMGB1 in heatstroke has been suggested in experimental models and clinical patients. By far, whether HMGB1 could be a potential therapeutic target in heatstroke is unknown. The objectives of this study are to use HMGB1 monoclonal antibody to specifically inhibit the activity of extracellular HMGB1 and to observe the possible protection of liver injury in a rat heatstroke model. METHODS: After treatment with neutralizing antibodies to HMGB1, rats were exposed to a high-temperature and high-humidity environment. At the time of heatstroke onset, the plasma and liver cytoplasm HMGB1 levels were detected by enzyme-linked immunosorbent assay. The histopathology of liver tissue was observed under light microscopy and transmission electron microscopy. Plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities were determined using the commercially available kits. Plasma tumor necrosis factor-α, interleukin-1ß (IL-1ß), and IL-6 were determined using enzyme-linked immunosorbent assay kits. RESULTS: HMGB1 levels in plasma and liver cytoplasm were both elevated in heatstroke rats, which were both associated with increased plasma ALT and AST levels. Histopathologic results showed that HMGB1 monoclonal antibody pretreatment could obviously alleviate the pathologic impairments of heatstroke rats. HMGB1 monoclonal antibody pretreatment could also downregulate plasma AST and ALT levels in heatstroke rats. Plasma tumor necrosis factor-α, IL-1ß, and IL-6 levels in heatstroke rats were elevated, which could be significantly suppressed by HMGB1 antibody pretreatment. CONCLUSION: HMGB1 could be a potentially effective treatment target in heatstroke. The pathogenic mechanism of heatstoke is complicated, which needs comprehensive prevention and treatment.

Role of HMGB1 in propofol protection of rat intestinal epithelial cells injured by heat shock.

Gut-derived endotoxin and pathogenic bacteria may be important causative factors of morbidity and death during heat stroke. However, as the key component of intestinal mucosal barrier, the molecular mechanism of how intestinal epithelial cells are injured by heat shock is remains unclear. After rat intestinal epithelial cells (IEC-6) had been exposed to heat shock, their viability was measured. Propofol, which plays an important role in anti-inflammation and organ protection, was investigated to see how it affected viability under this stress. Changes of high mobility group box 1 (HMGB1) in IEC-6 cells were measured with RT-PCR and Western blot assay at transcription and translational levels, respectively. Ethyl pyruvate (EP), a specific inhibitor of HMGB1 that can inhibit the release of HMGB1 without affecting its intracellular synthesis, was also investigated. Heat shock significantly reduced the intracellular level of HMGB1, and propofol inhibit its reduction. Propofol protected the heat shock-injured cells, at least partly through inhibiting the release of intracellular HMGB1 to reduce the direct or indirect cell damage caused by HMGB1. Pretreatment with high concentrations of EP also attenuated heat-shock injury.

Serum procalcitonin predicting mortality in exertional heatstroke.

BACKGROUND: The aim of this study was to test if Procalcitonin PCT value at the time of admission is a predictor of mortality and/or a diagnostic marker of concomitant infection in exertional heatstroke. METHODS: 68 patients with exertional heatstroke admitted to the multidisciplinary intensive care unit were studied. Serum PCT was detected by means of a specific and ultrasensitive immunoluminometric assay within 2 h of admission. The Acute Physiology and Chronic Health Evaluation (APACHE) II score was evaluated within 24 h of admission. RESULTS: There was no significant difference in PCT levels between concomitant infection and non-infection patients (p=0.712). Elevated PCT level in exertional heatstroke patients was associated with a more critical pathological state. PCT values in patients with multiple organ dysfunction syndrome (MODS) were significantly higher than those without MODS (p=0.007.). PCT values were also positively correlated with APACHE II scores (r=0.588, p=0.016). PCT values in non-survivors were higher than in survivors at univariate regression analysis (p=0.017). After adjusting for confounders, PCT concentration also remained an independent determinant of mortality (OR 2.98; 95% CI 1.02 to 4.41; p=0.039). Receiver operating characteristic curve for PCT concentration was located above the reference line, which shows an association with mortality. The area under the curve for PCT concentration (0.705; 95% CI 0.547 to 0.862) was statistical significantly (p=0.019). As a predictor of mortality, PCT value was inferior to APACHE II score. CONCLUSIONS: PCT value at the time of admission is an independent predictor of mortality, but maybe not a good indicator of concomitant infection in exertional heatstroke.

Proteomic analysis and identification of intestinal FBP as a predictor of gut dysfunction during heatstroke in mice.

BACKGROUND: Gut-derived endotoxin and pathogenic bacteria have been proposed to be an important causative factor of morbidity and death during heatstroke. However, the molecular changes underlying heat stress-induced small intestine lesions have not yet been well characterized. MATERIALS AND METHODS: A heatstroke model was established in mice, and the thermal response and pathologic changes in the small intestine were examined during heat stress. Proteins extracted from the small intestine of the heated and control mice were separated by two-dimensional (2D) gel electrophoresis, and different protein spots were further identified by peptide mass fingerprint. Targeted proteins were further verified by Western blot and immunohistochemistry analysis. RESULTS: Pathologic changes in the small intestine during heat stress were found to be substantial. Using 2 D gel proteomics we identified 14 proteins that were regulated differentially in the small intestine of the mice subjected to heat stress. These 14 identified proteins, seven were down-regulated and the other seven were up-regulated, appeared to be involved in metabolism, chaperone, cell skeleton, defense, signal transduction, DNA repair, and recombination. Using Western blot and immunohistochemical analysis, we further confirmed that down-regulated expression of intestinal fructose 1,6-bisphosphatase (FBP) correlated to the severity of small intestine lesions during heat stress and cooling treatment. CONCLUSIONS: Our results identified 14 differentially expressed proteins, which may contribute to the understanding of molecular mechanisms underlying intestinal injury during heatstroke. Furthermore, intestinal FBP, one of the seven down-regulated proteins, may function as a potential marker for prognosis of gut dysfunction.

Early elevated HMGB1 level predicting the outcome in exertional heatstroke.

BACKGROUND: Heatstroke is generally considered as a syndrome of hyperthermia associated with systemic inflammation leading to multiorgan dysfunction. High mobility group box-1 protein (HMGB1) has recently been identified as a late mediator of systemic inflammation inducing multiorgan dysfunction. Elevation of plasma HMGB1 in heatstroke has been observed in animals, but there is no data available about its changes in heatstroke patients. The objectives of this study are to observe the time course of plasma HMGB1 changes and assess its prognostic value in patients with exertional heatstroke. METHODS: Blood samples were taken from the patients with exertional heatstroke. Plasma HMGB1 level was detected by the enzyme-linked immunosorbent assay. C-reactive protein level was measured using a fully automated IMMAGE Immunochemistry System. Secreted HMGB1 in the culture supernatant of peripheral blood monocyte was assessed by immunoblotting. Acute Physiology and Chronic Health Evaluation II score was evaluated within 24 hours of admission. RESULTS: HMGB1 released into circulation at early stage, with peak levels occurring within 6 hours to 13 hours postheatstroke. Plasma HMGB1 levels remained markedly elevated in the following 6 days postheatstroke when compared with healthy volunteers (p<0.005). Positive correlation (r=0.798, p<0.001) was found between Acute Physiology and Chronic Health Evaluation II score and HMGB1 level at admission. HMGB1 levels at admission between survivors and nonsurvivors were significantly different (p<0.001). Receiver operating curve analysis showed that at a level of 47 ng/mL, HMGB1 level at admission indicated lethality with 77.4% sensitivity and 84.2% specificity. CONCLUSIONS: HMGB1 level at admission is an indicator of the severity of illness and a useful mortality predictor in exertional heatstroke.

Intestinal inflammation and tissue injury in response to heat stress and cooling treatment in mice.

Gut-derived endotoxin and pathogenic bacteria have been proposed to be important causative factors of morbidity and mortality due to heat stroke. However, the molecular mechanisms underlying the small intestinal lesions caused by heat stroke have yet to be well characterized. In order to verify the possible inflammatory pathogenesis of intestinal tissue injury, a mouse heat stroke model was established. Cooling treatment was applied, mimicking the clinical therapy. Morphologic changes in intestinal tissue and 10 cytokines and chemokines produced from ileum tissue were detected, and their correlation was analyzed. As a result, intestinal lesions in mice worsened with the increase in rectal core temperature (Tc) during heat stress. When heat stress was halted at a Tc of no more than 41°C followed by cooling treatment, pathological recovery from the injury of heat stress was observed. However, when cooling treatment was applied after the Tc reached 42°C, the lesions continuously deteriorated until the animals succumbed. The levels of pro-inflammatory (IL-1ß, IL-2, IL-6 and TNF-α) and anti-inflammatory (IL-10, IL-12p40) cytokines showed significant changes at different time points during the heat stress and cooling treatment, but no changes in GM-CSF, MCP-1, MIP-1α and IL-4 were observed. Levels of IL-1ß, IL-10 and IL-12p40 were moreover significantly correlated with intestinal injury scores. A significant inverse linear correlation was observed between intestinal injury and IL-12p40 levels. In conclusion, this study provided insight into the inflammatory pathogenesis of intestinal tissue injury after heat stress and cooling treatment in a mouse model, and presented a potential biomarker for the evaluation of intestinal injury during heat stroke.

Pathological changes in the lung and brain of mice during heat stress and cooling treatment.

BACKGROUND: Heatstroke often leads to multiple organ dysfunction syndrome (MODS) with a death rate of 40% or a neurological morbidity of 30%. These high rates in patients with heatstroke are largely due to the progression of heat stress to MODS, resulting in no specific treatment available. This study aimed to develop a mouse model of heat stress and determine the pathological changes in the lung and brain during heat stress and cooling treatment. METHODS: A mouse model of heat stress was established in a pre-warmed incubator set at 35.5 ± 0.5°C and with a relative humidity of 60% ± 5%. Rectal temperature was monitored, and at a temperature of 39 °C, 40 °C, 41 °C, or 42 °C, the mice were sacrificed. The remaining animals were removed from the incubator and cooled at an ambient temperature of 25 ± 0.5 °C and a humidity of 35% ± 5% for 12 or 24 hours at a temperature of 41 °C or for 6 hours at a temperature of 42 °C. The control mice were sham-heated at a temperature of 25 ± 0.5 °C and a humidity of 35% ± 5%. The lungs and brains of all animals were isolated. Hematoxylin and eosin staining and light microscopy were performed to detect pathological changes. RESULTS: All mice demonstrated a uniform response to heat stress. A low degree of heat stress induced marked pathological changes of the lungs. With the rise of the temperature to 42°C, progressively greater damage to the lungs with further congestion of the lung matrix, asystematic hemorrhage of alveolar space, abscission of alveolar epithelial cells, and disappearance of pulmonary alveolus tissue structure were detected. However, absorption of congestion and hemorrhage as well as recovery of pulmonary alveolus tissue structure was observed following cooling treatment at an ambient temperature. With a low degree of heat stress, the brain only showed moderate edema. Neuronal denaturation and necrosis were detected at a temperature of 42°C. Interestingly, the lesions in the brain were further aggravated at 42 °C regardless of cooling treatment, but recovery was observed after cooling treatment at 41 °C. CONCLUSIONS: The pathological changes of the lungs and brain of mice showed distinctive lesions following heat stress and cooling treatment, and they were correlated with the time and duration of cooling treatment. The results of this study are helpful for further study of the mechanisms linking heatstroke.

[Combined effect of high mobile group box-1 protein and lipopolysaccharide on release of cytokines from human HepG2 cells].

OBJECTIVE: To study the effects of high mobile group box-1 protein (HMGB1) and lipopolysaccharide (LPS) singly or in combination on release of cytokines from human liver carcinoma cell line (HepG2). METHODS: HepG2 cells were cultured, and purified HMGB1 protein was prepared by chromatography on Ni(2+)-NTA Sepharose column under natural conditions with recombinant expression plasmid pET14b-HMGB1. Different concentrations of HMGB1 (0, 0.01, 0.1, 1, 10 mg/L) and LPS (0, 0.1, 1, 10, 100 mg/L) were added into the cultured cells for 24 hours, respectively. Then the supernatant were collected to detect the levels of granulocyte/macrophage colony stimulating factor (GM-CSF), interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), and interleukin-1 beta (IL-1 beta), IL-2, IL-4, IL-6, IL-8, IL-10, and IL-12 by using LiquiChip system. Lastly, HepG2 cells were co-stimulated with 10 mg/L LPS and 1 mg/L HMGB1 for 24 hours. The supernatant were collected to determine the levels of above ten of cytokines . RESULTS: The expression and release of IL-6 and IL-8 increased from HepG2 cells after being stimulated by LPS in a dose-dependent manner, but there were no changes in other eight kinds of cytokines (P<0.05 or P<0.01). Low concentration of HMGB1 could up-regulate the expression of IL-6 and IL-8 in HepG2 cells (both P<0.01). But the extent of induction decreased with higher concentration of HMGB1. Similar to LPS, there was no effect of HMGB1 on the expression of other eight kinds of cytokines from cultured HepG2 cells. Furthermore, high concentration of HMGB1 could obviously inhibit the upregulation of IL-6 and IL-8 by high concentration of LPS when the HepG2 cells were co-stimulated with LPS and HMGB1 (both P<0.01). CONCLUSION: HepG2 cells could only express and release a few kinds of cytokines when the cells were stimulated with pro-inflammatory agents, such as LPS or HMGB1. Two kinds of cytokines, IL-6 and IL-8 could be up-regulated by LPS and low concentration of HMGB1, and HMGB1 acted as an inhibitor of LPS to down-regulate the expression and release of IL-6 and IL-8 from HepG2 cells.

Serum procalcitonin at the time of admission to the ICU as a predictor of short-term mortality.

OBJECTIVE: This purpose of this study was to determine if serum procalcitonin (PCT) concentration at the time of admission to the ICU is a predictor of all-cause short-term mortality. DESIGN AND METHODS: This prospective cross-sectional study was conducted over a 16-month period with 86 consecutive critically ill patients. The semi-quantitative PCT-Q test was performed and APACHE II scores and C-reactive protein (CRP) concentrations were determined within 24 h of admission. RESULTS: PCT-Q test value was a better predictor of all-cause short-term mortality than CRP value or APACHE II score. PCT > or = 10 ng/mL was highly and independently correlated with mortality. Use of PCT-Q > or = 10 ng/mL was superior to use of APACHE II > or = 25 or CRP > or = 10 mg/dL as a predictor of poor outcome. CONCLUSIONS: A PCT-Q value > or = 10 ng/mL obtained at the time of admission to the ICU is a strong predictor of short-term mortality.

[Clinical effects of ulinastatin and thymosin alpha1 on immune-modulation in septic patients].

OBJECTIVE: To analyze clinical effect of immuno-modulatory therapy with ulinastatin and thymosin alpha1 on patients with sepsis. METHODS: Two hundred and forty-two septic patients admitted to Guangzhou General Hospital of Guangzhou Military Command intensive care unit (ICU) during 2004.10-2008.6 were included, and they were randomly divided into treatment group (128 cases) and control group (114 cases). The patients in control group were given regular conventional treatment according to Surviving Sepsis Campaign (SSC) in 2004, including early fluid resuscitation, antibiotic therapy, mechanical ventilation (MV) and blood purification. The treatment group received conventional treatment plus immuno-modulation therapy including ulinastatin (first 200 kU injection intravenous twice a day for 4 days and 100 kU for another 6 days) and thymosin alpha1 (1.6 mg subcutaneous twice a day for 4 days, followed by 1.6 mg per day subcutaneous for another 6 days). The total treatment course was 10 days. General demographics were observed, and acute physiology and chronic health evaluation II (APACHE II) scores were recorded. Serum interleukin-6 (IL-6), IL-10 levels of peripheral blood were detected by enzyme linked immunosorbent assay (ELISA). Peripheral blood CD14(+) monocyte human leucocyte antigen DR (HLA-DR) expression, and ratio of helper T lymphocyte 1 (Th1) cytokines interferon-gamma (CD4(+)IFN-gammaww(+)), and Th2 cytokines (CD4(+) IL-4(+)) were assessed with flow cytometer. Duration of infection and MV, length of ICU stay, rate of development of multiple organ dysfunction syndrome (MODS) and mortality rate on 28 days were observed as end-point. RESULTS: Before treatment, there was no difference in all biomarkers between two groups (all P>0.05). After treatment, peripheral blood CD14ww+ monocyte HLA-DR expression and the ratio of CD4(+)IFN-gamma (+)/CD4(+) IL-4(+) increased significantly in the treatment group (both P<0.05), with serum IL-6, IL-10 levels and APACHE II scores all reduced remarkably (all P<0.05). The values showed significant differences compared with those of control group (all P<0.05). The MODS development rate in the treatment group was much lower than that of control group (21% vs. 47%, P<0.05), and the length of use of MV was significantly reduced [(6.08+/-2.46) days vs. (8.23+/-3.47) days, P<0.05]. There was no difference in the infection duration and length of ICU stay (both P>0.05). The mortality rate on 28 days in the treatment group was much lower than that in control group (20% vs. 33%, P<0.05). CONCLUSION: The immuno-modulation therapy of ulinastatin and thymosin alpha1 can remarkably improve the duration of MV and the development rate of MODS and mortality rate on 28 days in the patients with sepsis, probably due to its effect in ameliorating the immuno-imbalance state of the patients. However, the duration of infection and length of ICU stay are not effected.