| Heatstroke(HS)is a catastrophic heat-ralated disease combined with multiple organ dysfunction which needs supportive treatment.Its mortality rate is about 10-15%and can reach more than 40%if developed into multiple organ dysfunction syndrome(MODS).Even under vigorious cooling and organ-supportive therapy,the mortality rate remains high,and even 30%of the survivors was left with long-term neurological sequelae.As global warming and the frequency and strength of heat wave assault increases,the predicted morbility and mortality rate of HS will raised gradually year after year.Meanwhile,the treatment of HS and its complications needs large precious resources and brings heaurgently required to improve the clinical practices.vy financial burden on families and society,and the targeted resolvents areThe coagulopathy is a distinguishing feature of severe HS similar to severe sepsis,it can rapidly developed into disseminated or diffuse intravascular coagulation(DIC)with more violent and prompt progress.It has the characteristic histopathology of extensive fibrin deposition in microvessel and can manifested as multiple organ hemorrhage like cerebral,pulmonary and gastrointestinal bleeding directly causing death at early stage.Under the advanced study of the characteristics and mechanism of HS-related coagulopathy,early detection and blocking of coagulopathy development is a key to improve HS-related DIC and outcome.The pathogenesis of HS-induced acute coagulopathy remains unclear.It is likely that endothelial impairment may be the start in coagulation and imflammation initiation and interaction.In fact,the endothelial glycocalyx(EG)between endothelium surface and bloodstream is not ignored.It is found that EG has multiple physiological regulation and involving into the vascular permeability,white blood cells and platelet adhesiveness,inflammation,bloodstream resistence and coagulation.EG impairment is an important door of endothelial damage based on its anatomincal position and mobility,and it may play a critical role in magnifying the agitation of HS-related inflammation and coagulation.The structure of EG includes proteoglycan,glycosaminoglycans,glycoprotein,glycolipid and soluble plasma substances,etc.Syndecan-1 is a main membrane proteoglycan,and HA is a major element of glycosaminoglycans.The serum level of Syndecan-1 and HA is closely associated with EG density and can be used as sensitive biomarkers of EG impairment.At present,most of the studies of serum level of Syndecan-1,HA and EG impairment focus on the vascular inflammation and permeability conditioning of acute and chronic cardiovascular disease like diabetes,coronary heart disease and ischemia reperfusion,and it is reported that EG impairment is involved in the endotoxin-induced coagulopathy and pulmonary injury.However,it is seldom covered that whether EG impairment is related to endothelial damage,inflammation initiation and coagulopathy.Consequently,our research hypothesis,the HS first led to the destruction of EG,thus further lead to endothelial injury,inflammation,amplification and blood coagulation activation,eventually leading to blood coagulation disorders.Our study retrospectively analyzed the clinical characteristics of HS-related coagulopathy and the association with organ function and clinical outcome,and prospectively observed the effect of EG on the HS-related coagulopathy and outcome prediction.besides.On the one hand,we observed the relationship between EG and HS-related coagulopathy through ROS and its protective agent N-acetylcysteine(NAC)in vitro and NAC protection in vivo in order to prove the importance of EG impairment in the endothelial adhesiveness and secretion,inflammation and coagulopathy.On the other hand,the effects of Syndecan-1 and HA on HS-related coagulopathy and outcome prediction were testified in HS rat.Our study can bring forward the EG protection and endothelial injury prevention ahead of endothelial impairment protection,and can explore more effective methods and biomarkers to early discover and monitor HS-related coagulopathy,predict the clinical outcome and provide treatment target.The retrospective observation of the occurence rate,time distribution feature of HS-related coagulopathy and the relationship between coagulation parameters and outcome93 cases of patients diagnosed heatstroke were included in intensive care unit of Guangzhou general hospital of Guangzhou military command during 2005.6-2014.10,and the coagulopathy characteristics were analyzed by rank and test analysis and through logistic regression analysis to discuss prognostic parameters.89 patients conducted ISTH score statistics.The overt DIC(ISTH score = 5)incidence rate was 55.06%as the overt ISTH scores used as diagnostic criteria.At admission within 24h,the overt DIC incidence rate was 65.67%and it decreased to 33.33%after 72h admission.Compared with the patients of more than 24h before hospitalized,the incidence of overt DIC was statistically increased at the patients within 24h hospitalized(X2=12.747,P=0.002).The PT abnormality rate occurred within 24h admission was 42.65%and increased to 85.71%within 24～48h,reduced to 75%in 48～72h and gradually cut down to 58.33%after 72h.APTT abnormality rate occurred within 24h admission was 35.29%and increased to 85.71%within 24～48h,reduced to 75%in 48～72h and gradually cut down to 41.67%after 72h.The peak abnormality of PT and APTT value occurred at 24～48h after admission.Fib abnormality rates were 6.06%,28.57%,33.33%and 16.67%,with D-dimer rate of 74.00%,100%,100%and 71.43%,respectively in each time quantum.PLT abnormality rate was 68.57%,28.57%,0.00%and 33.33%with peak within 24h.Based on the fact the ACT of Sonoclot indexes has similar coagulatory importance as PT and APTT,its abnormality rate within 24h was 61.54%which was higher than those of PT and APTT.CR present the conversion rate of fibrinogen and is similar to Fib,its abnormality rate within 24h was 33.33%and more than that of Fib.In our study,the mortality rate of HS patients combined with overt DIC were much higher than that of those without overt DIC(P=0.000),and ISTH score was significantly positively related to APACHEII scores(r = 0.745,P = 0.745).Logistic regression anlalysis indicated that D-dimer and ACT were closely related with poor outcome with partial regression coefficient B of 0.059 and 0.009 and odds ratio of 1.061(95%CI:0.990-1.137)and 1.009(95%CI:1.000-1.018).The preliminary discussion of relationships between serum EG biomarkers of Syndecan-1 and HA and HS-related coagulopathy and clinical outcome in the rats16 cases of patients diagnosed as heat stroke within 12h after admission in ICU of Guangzhou general hospital of Guangzhou military command during 2013.6-2014.6 and 11 cases of healthy male adults were included as control group.The relationship between serum EG biomarkers of Syndecan-1 and HA and HS-related coagulopathy and clinical outcome were analyzed.The results showed that DIC scores were positively associated with serum HA and Syndecan-1 levels(r=0.831,P=0.000 and r=0.788,P=0.000,respectively).TAT levels at admission was positively correlated with DIC scores(r=0.722,P=0.002)and serum TM and PAP levels were unrelated to DIC scores(r=0.243,P=0.365 and r=0.478,P=0.061,respectively).The serum levels of Syndecan-1 and HA in HS group were much higher than those in control group(217.90±138.22 ng/ml vs 37.73±11.03 ng/ml,and 2976.85±1624.21 ng/ml vs 278.24±216.29 ng/ml,respectively).and they are remarkably increased in the HS with MODS patients than those without(P<0.001).The serum levels of Syndecan-1 and HA in death subgroup were higher than those in survival subgroup(P=0.014,P=0.000,respectively),and they were positively correlated with APACHEII scores(r=0.837,P=0.000 and r=0.787,P=0.000,respectively).The ROC analysis indicated that serum HA levels>281.7ng/ml was the optimum diagnostic cut-off point with sensitivity of 100%,specificity of 100%and AUC of 1.00(P=0.001146).the serum Syndecan-1 level>3215ug/ml was the optimum diagnostic cut-off point with sensitivity of 100%,specificity of 90%and AUC of 0.90(P=0.009264).The effect of EG on coagulopathy and clinical outcome in HS rats1.The characteristics and relationship between coagulatory parameters and EG impairment biomarkers Syndecan-1 and HA in HS ratsIn order to display the whole characteristics of dynamic changes of coagulation in rats with heatstroke.The rats were randomly divided into control group(group C,n=6)and HS groups which further classified into 9 subgroups such as 41 ℃,42℃,43 ℃,HS-0h,2h,6h,24h,72h and 216h according to different temperature and time of recovery(n=6).The relationships between coagulatory parameters and EG impairment biomarkers were observed.Since the core temprerature(Tc)reached 41℃ APTT and PT gradually prolonged in HS groups(P<0.05).At 43℃ APTT extension was much longer than that in group C(P<0.05).In HS-Oh group,PT was much longer than that in group C(P<0.055).Both PT and APTT reached the max detection value at HS-24h,and were increased significantly than those in group C(P<0.01).The Fib and PLT present no significantly change compared with those in control group in the early HS period and were remarkably decreased in 24h after HS occurrence(P<0.01).The above indexes began to recover in 72h after HS occurrence.The ACT was independent with normal value at the HS-Oh(P>0.05)and extended gradually two hours later,lengthened outstandingly in 24h after HS occurrence(P<0.01)and decreased to normal in 72h.CR raised significantly at 43 ℃and reduced to normal when HS occurred.In addition,CR gradually reduced at 2h,6h and 24h(all P<0.05)of resuscitation with minimum value at 24h and regain normal at 72h.Since Tc reached 43,PF progressively decreased(P<0.05),and it reduced below the lower detection limit at 24h and returned to normal at 72h.The serum levels of Syndecan-1 and HA were increased since HS started(P<0.01)and reached peak at 24h and reduced to normal at 72h or 216h respectively(P>0.05),with similar trends especially elevatory time interval with other traditional coagulatory parameters and Sonoclot indexes.However,the biomarker of coagulation such as TAT and PAP and endothelial injury such as vWF and ET-1 were no changed at Oh after HS occurrence(P>0.05)and start to increase at 2h or 6h after HS occurrence(P<0.01)although the time of reaches at peak and restore were keeping the same time with other coagulation parameters.2.The effect of NAC on the EG impairment and inflammation-coagulation disturbance.To further confirm the effect of EG impairment in coagulation disturbance,NAC was introduced to observe the NAC antioxidant effect on the EG.The rats were divided into normal control group(n=6),HS group(n=6)and HS with NAC treatment group(group HS+NAC,n=6).The above parameters at 2h after HS occurred were recorded and analyzed.The EG of pulmonary capillary was intact in control group under electronic microscopy,and was greatly reduced in HS group with EG rupture,the EG impairment was remarkably relieved after NAC administration.The laser confocal fluorescence immune detection showed the Syndecan-1 expression in pulmonary capillary was reduced after HS occurred(P<0.05),and recovered to similar levels after NAC intervention(P>0.05).Compared with that in control group,the serum levels of HA was higher in HS group(152.06±36.47 vs 81.25± 19.26,P=0.002)and reduced in HS+NAC group compared with HS group(102.50±6.26 vs 152.06±36.47,P=0.025)。In HS+NAC group,the abnormal coagulatory parameters of PT,APTT,ACT,CR and PF improved significantly(all P=0.000),and the IL-6 level were much lower than those in HS group(109.41 ±9.63 vs 221.16±22.91,P=0.000)and TNF-a level was also lower than that in HS group but with no statistical significance(102.50±36,46 vs 127.52±38.43,P= 0.500).3.The relationship between EG-impairment biomarker Syndecan-1 and HA and outcome in HS rats.22 rats were divided into death group and survival group according to the prognosis.The relationship between the EG-impairment biomarker Syndecan-1 and HA and outcome were analyzed.The results showed that the serum Syndecan-1 and HA levels were increased greatly in the death group than those in survival group(2.29± 1.36 VS0.20±0.15,P=0.000),(197.25±61.34 VS 13.47±13.87,P=0.000).The effect of EG impairment on the endothelial adhesivenessHUVEC were cultured and harvested in vitro and divided into control group,HS group,H2O2 stimulation group and NAC group.the ICAM-1 and VCAM-1 levels were detected to observed the EG and endothelial adhesiveness variations,the HUVEC EG thickness was reduced significantly in HS group and H2O2 group(P<0.05),and was alleviated in NAC group which was similar to control group(P>0.05).The adhesive WBC increased in HS group(190±15 per view vs 130±15 per view,P<0.001)and it was similar to H2O2 group(226±23 per view vs 190±15 per view,P>0.05).The adhesive WBC reduced distinctly in NAC group than that in HS group(138±8 per view vs 190± 15 per view,P>0.05).Compared with control group,the ICAM-1 and VCAM-1 levels were higher in HS group(P<0.05)and H2O2 group(P<0.05),and was similar in NAC group(P>0.05).Based on the above results,we concluded that:1.DIC occurred frequently in HS patients with total incidence rate of 55.06%.Within 24h after admission,the incidence rate of overt DIC was 65.67%.The mortality rate of HS patients raised significantly if combined with DIC.2.The sonoclot coagulatory parameters like ACT and CR had higher positive rate than those in conventional coagulatory indexes of APTT,PT and Fib within 24h after HS occurred.Besides,ACT and D-dimer were independent risk factors,which suggested that ACT and CR were more sensitive than conventional coagulatory indexes.ACT and CR can predict outcome combined with D-dimer in HS patients.3.The serum levels of HA and Syndecan-1 may be closely related to HS-related coagulopathy and can predict clinical outcome.4.The coagulation abnormality occurred in the Tc rising stage in HS rats.progressive coagulation disturbance occurred after HS started and reached peak at 24h and gradually recovered at 72h,which suggested coagulation initiation was utmost early event in HS and may be the critical pathogenesis in HS development that needed early focus and intervention.5.EG reduction of pulmonary capillary was closely associated with coagulation abnormalities.NAC can protect EG to relieve endothelial impairment and inflammation responses and improve coagulatory parameters,which suggested EG can induce aggravation of endothelial impairment and inflammation responses to further cause coagulation disturbance and DIC.6.Heat stress can decrease EG thickness,increase adhesiveness of endothelium and WBC,increase the expression of supernatant ICAM-1 and VCAM-1 in HUVEC.NAC can alleviate the EG impairment,reduce the adhesiveness of endothelium and WBC and decrease the expression of supernatant ICAM-1 and VCAM-1,which indicated the EG impairment may affect the endothelium adhesiveness to induce HS-related coagulopathy.7.Endothelial glycocalyx may become new therapeutic targets of protection endothelium and improvement of blood coagulation disorder during heatstroke. |
PDF Full Text Request