Early Warning,therapeutic Effect And Mechanism Of Parathyroid Hormone On Ischemic Myocardial Injury

AIM1.Diagnostic value of parathyroid hormone（PTH）in acute coronary syndrome（ACS）;2.The role of PTH in ischemic myocardial cell injury;3.Mechanism of PTH protection against ischemic myocardium.Methods1.Continuity included 630 patients who were admitted to hospital for chest pain between January 2017 and December 2019 and whose coronary heart disease was eventually confirmed by coronary angiography or coronary CT angiography.Patients were divided into stable coronary heart disease（SCAD group,n=379）and acute coronary syndrome（ACS group,n=251）.Plasma samples were collected to analyze the differences in PTH expression and general conditions between the ACS group and the SCAD group.2.ROC curve was used to evaluate the diagnostic efficacy of PTH for ACS.3.The hypoxic injury model of cardiomyocytes was established:30%hydrogen peroxide（H₂O₂）solution was diluted into 100umol/L,200umol/L and 500umol/L solution gradiates,and cultured for 12h,24h and 36h,respectively.The cell viability was detected by CCK-8 method.The optimum action time and concentration of H₂O₂in this experiment were obtained.Statistical software was used to compare differences between groups.4.The concentration of PTH at 10^-5mol/L,10^-6mol/L,10^-7mol/L,10^-8mol/L and 10^-9mol/L were co-cultured with H9C2 cardiomyocytes in normal survival state,and the cell viability was detected by CCK-8 to obtain the optimal concentration.The cells were cultured at 12h,24h,36h,48h and 60h.CCK-8 was used to detect cell viability again,and the optimal time of action was obtained.Statistical software was used to compare differences between groups.5.In the above model,it can be seen that the optimal reaction condition is 12 hours of 100umol/L H₂O₂culture,and then 10^-5mol/L,10^-6mol/L,10^-7mol/L,10^-8mol/L,10^-9mol/L concentration of PTH and 100umol/L H₂O₂co-culture.The optimal action time and concentration were obtained.CCK-8 was used to detect cell viability and observe the differences among groups.6.H9C2 cell group,100umol/L H₂O₂group,10^-7mol/L PTH+100umol/L H₂O₂,10^-9mol/L PTH+100umol/L H₂O₂were divided into 4 groups,and 12-well plates were laid to measure P62,Beclin1 and other related autophagy proteins.P53 apoptosis protein.Results1.In the comparison of general data between the two groups,the basic clinical data of ACS group showed that the ratio of smoking composition was higher than that of SCAD group,the ratio of atrial fibrillation and hypertension groups was lower than that of SCAD group,and the age and body mass index（BMI）values were higher than that of SCAD group.The levels of leukocyte,total cholesterol,low-density lipoprotein（LDL）,apolipoprotein B（Apo B）,serum calcium,serum phosphorus,PTH,serum creatinine and globulin in the SCAD group were higher than those in the SCAD group.Lymphocyte（LY）,high density lipoprotein（HDL）,apolipoprotein A（Apo A）,serum phosphorus,globulin and cystatin C were lower than those in SCAD group（P<0.05）.Univariate logistic regression analysis showed that there were significant differences in lymphocyte,platelet,albumin,total cholesterol,LDL,HDL,Apo B,lipoprotein a,PTH,serum creatinine（Scr）,globulin and SCAD group（P<0.05）.Multivariate logistic regression analysis showed that LY,ALB（albumin）,LDL,HDL,cystatin C and PTH were independent predictors of ACS and SCAD（P<0.05）.2.ROC curve results showed that when the concentration of PTH was 58.45ng/ml,the difference between SCAD and ACS was the strongest,the sensitivity was 45.2%,the specificity was 67.6%,and the diagnostic efficiency was the highest（AUC=0.569,95%CI:0.524-0.614,P<0.01）.3.The optimal condition was the decreased cell viability after 12 hours of100umol/L H₂O₂culture.4.The optimum condition of PTH was cultured at 10^-7mol/L for 48 hours.5.PTH in this concentration range can have a protective effect on the damage caused by 100umol/L H₂O₂,and the protective effect is strongest at 10^-7mol/L（P>0.05）.6.H9C2 cells showed increased P53 expression after H₂O₂treatment,which was reversed by PTH.In addition,compared with H₂O₂alone,the expression of P53 protein in H9C2 cells pretreated with PTH and incubated with H₂O₂decreased significantly in10^-7mol/L compared with 10^-9mol/L.Autophagy related proteins such as Beclin-1 and p62/SQSTM1 were significantly decreased（P<0.05）and p62/SQSTM1 were significantly increased（P<0.05）when treated with H₂O₂alone.Autophagy level was increased when combined with PTH and H₂O₂.In addition,the Beclin1 protein level and p62/SQSTM1 were significantly increased（P<0.05）when 10^-7mol/L was higher than 10^-9mol/L.Conclusion1.PTH is higher than SCAD in patients with ACS,and PTH may be an auxiliary diagnostic indicator of ACS.2.Protective effect of PTH on ischemic injury of H9C2 cells;3.PTH alleviates ischemic myocardial injury by promoting autophagy and inhibiting myocardial apoptosis.