Changes Of Heat Shock Protein 70 Levels In Patients With Acute Coronary Syndrome And Their Clinical Significance

Background:Heat shock protein 70s(HSP70s),also called stress proteins,are mainly intracellular molecules.HSP70s can exert cytoprotective effects as chaperones.In response to stress,they can be transported to and reside in the cell membrane,or be released to the surroundings.It's not certain about the exact effects of extracellular HSP70s, but it has been reported that extracellular HSP70s have a contributory role in inflammation and atherosclerosis.However,the relationship between human coronary heart disease(CHD) and serum HSP70 levels remains unknown. We measured serum HSP70 levels in CHD patients,in order to examine whether serum HSP70 levels are associated with CHD,and to explore their clinical significance.Metheds:From April through August 2008,66 patients with diagnosed CHDand 21 healthy controls were enrolled in this study.They are divided into 3 groups including acute coronary syndrome group[ACS,n=46, composed of acute myocardial infarction group(AMI,n=23) and unstable angina pectoris group(UAP,n=23)],stable angina pectoris group(SAP,n=20), or non-coronary heart disease group(non-CHD,n=21).Serum HSP70 levels were determined using ELISA kits.Meanwhile high sensitive C-reactive protein(hs-CRP),fasting blood sugar(FBS),total cholesterol(TC), triglyceride(TG),low-density lipoprotein cholesterol(LDL-C),high-density lipoprotein cholesterol(HDL-C),and peripheral White Blood Cell(WBC) count were measured.Results:(1)Serum HSP70 levels in ACS subjects(4.72±2.01 ng/ml,Mean±S.D.) were significantly higher than that in SAP subjects(2.32±1.44,ng/ml)and non-CHD subjects(2.41±0.96 ng/ml)(p<0.01).But the difference of serum HSP70 levels between SAP subjects and non-CHD subjects was not significant statistically.(2)Among patients with CHD,serum HSP70 levels in AMI patients (5.94±0.41 ng/ml,Mean±S.E.) are much higher than that in UAP subjects (3.49±0.23 ng/ml)(p<0.01),and serum HSP70 levels in UAP subjects are much higher than that in SAP subjects(2.33±0.32 ng/ml)(p<0.01).(3)Serum HSP70 levels were associated positively with WBC(R=0.337, P<0.01),CK-MB(R=0.653,p<0.01) and Lg[hs-CRP](R=0.658,p<0.01), but negatively with HDL-C(R=-0.211,p<0.05) among all the subjects.(4)HSP70 is significantly and independently associated with ACS in logistic regression models.Conclusions:(1) HSP70s may serve as a sensitive biomarker of myocardial damage and necrosis.(2) Serum HSP70 levels may reflect the extent of inflammation.(3) The expression and release of HSP70 may be associated with HDL.(4) Serum HSP70 concentration may be an independent predictor of ACS.