CRP In Myocardial Ischemia-reperfusion Injury And Subacute Stent Thrombosis After PCI

Objective Ischemia / reperfusion injury(IRI)is an inflammatory reaction during long-term ischemia-reperfusion injury.It is suggested that C-reactive protein(CRP)may play an important role in inducing IRI.However,the effect of CRP on myocardial IRI and its underlying mechanism have not been fully elucidated.And,to investigate the relationship between CRP and myocardial IRI and its underlying mechanism.At present,the diagnostic methods of stent thrombosis are still limited,and the gold standard depends on coronary angiography.This study aims to explore the value of combined serum markers hs-CRP and D-dimer in predicting SST after PCI in patients with AMI.Methods We used oxygen-glucose deprivation / reoxygenation(OGD / R)to simulate ischemia / reperfusion in neonatal SD rat cardiomyocytes.After hypoxia for 3 hours,both glucose and serum deprivation were given to induce reperfusion injury and then reperfusion for 1 hour.Cell viability was measured by MTS assay and myocardial cell injury was evaluated by lactate dehydrogenase(LDH)(LDH)leakage.Mitochondrial membrane potential was measured by tetramethylrhodamine ethyl ester(TMRE),mitochondrial permeability transition pore(m PTP)opening was measured by calcitonin / AM,and TMRE and caocein / AM were observed by laser scanning confocal microscopy.In addition,we studied the signal transduction pathway of ischemia / reperfusion injury mediated by CRP by Western blot analysis.A retrospective analysis was made on the patients who received PCI for AMI from January 2012 to January 2018.The patients with SST after operation were divided into SST group and control group according to age and sex ratio.The risk fa ctors of coronary heart disease(gender,age,body mass index,etc.),clinical data(systolic blood pressure,diastolic blood pressure,CK,CK-MB,etc.),coronary angiography results(diseased vessels,poor stent adherence,etc.)were compared between the two groups.The t test was used to compare the measurement data between the observation group and the control group.The chi square test was used to compare the count data between 2 groups.Univariate analysis of the differences between the two groups will be statistically significant indicators into logistic regression analysis,screening for independent risk factors of SST,OR value and 95% confidence interval.The ROC curve was established to evaluate the predictive value of the index with large OR value for SST.The predictive value of the combination of hs-CRP and D-dimer for SST was evaluated according to the best diagnostic point determined by Jordan index.Results Compared with OGD / R group,after 10μg / m L CRP intervention was performed,the cell survival rate was significantly decreased(82.36% ±6.18%vs 64.84% ±4.06% vs 0.0007,P= 0.0007),LDH leakage(145.3 U / L ±16.06 U / L vs 208.2 U / L ±19.23 U / L,P = 0.0122).During myocardial ischemia / reperfusion,CRP also activated m PTP opening and decreased mitochondrial membrane potential.Pretreatment with 1 μ M Atorvastatin(Ator)before CRP intervention could protect cardiomyocytes from IRI.Mitochondrial K ATP channel opener diazoxide and m PTP inhibitor cyclosporine A also counteracted the role of CRP in this process.Compared with OGD / R group,After pretreatment with CRP,the level of extracellular signal-regulated kinase(ERK)1 / 2 was significantly increased(170.4% ±3.00%vs 93.53% ±1.94,P < 0.0001).Western blot analysis showed that the expression of Akt was significantly activated after co-treatment of Ator and CRP(184.2% ±6.96 vs 122.7% ±5.30%,P = 0.0003).ERK 1 / 2 phosphorylation was significantly decreased.A totally of 9261 AMI patients treated with PCI,72 cases(0.78%)had SST after operation.There was no significant difference in gender composition,age structure and risk factors between the two groups(P > 0.05).The postoperative D-dimer(P = 0.000),hs-CRP(P = 0.000),the number of poor stent adherence(P = 0.000)and stent placement(P = 0.000)in SST group were higher than those in control group,and the left ventricular ejection fraction(P = 0.000)was lower than that in control group.Multivariate logistic regression analysis showed that LDH and the number of stents had no significant effect on SST(P > 0.05),but D-dimer(OR = 3.209,P = 0.002),hs-CRP(OR = 7.892,P = 0.003),poor stent adherence(OR = 8.612,P = 0.019),GLU(OR = 1.233,P = 0.026)were independent risk factors for SST,and left ventricular ejection(LV)was associated with poor stent adherence.OR=0.891(P=0.016)is a protective factor for SST.The best cutoff value of Hs-CRP for SST was 20.81 mg/L,its sensitivity was 41.7%,specificity was 98.6%;the best cutoff value of D-dimer for SST was 1.17 ug/L,sensitivity was 95.8%,specificity was 30.0%;the area under the ROC curve of Hs-CRP combined with D-dimer was 0.875,the best cutoff value for SST was 14.28,sensitivity was 77.8%,specificity was 80.5%.ConclusionOur results show that CRP directly exacerbates IRI,in cardiomyocytes.This effect is mediated mainly by inhibiting mitochondrial ATP sensitive potassium(mito K ATP)channels and promoting the opening of m PTP.These effects are counteracted by Ator.One of the mechanisms that can reduce the IRI induced by CRP may be related to the continuous activation of ERK signal transduction pathway.Although the incidence of SST is low after PCI,it should be emphasized because of its high mortality.D-dimer,hs-CRP,poor stent adherence and elevated fasting blood glucose were independent risk factors for SST,and elevated left ventricular ejection fraction was a protective factor for SST.The combined diagnostic index hs-CRP-D-dimer established on the basis of hs-CRP and D-dimer can be used as an ideal predictor of SST in patients with AMI after PCI and is worthy of clinical application.