Objective:Keshan disease(KD)is a mitochondrial cardiomyopathy.The present study explored the roles of peroxisome proliferator-activated receptor(PPAR)-γ coactivator-1α(PGC-1α),the key regulator of mitochondrial structure and function,and its coactivators in myocardial injury in chronic KD.Furthermore,the usefulness of these molecules in the diagnosis of chronic KD was assessed.Methods:In the present case-control study,43 patients with chronic KD and 30 healthy individuals living in KD endemic areas were included.The myocardial injury indicators and mRNA expression levels of PGC-1α,nuclear respiratory factor 1(NRF1),PPARα,and estrogen-related receptor alpha(ERRα)in peripheral blood were examined.Results:It was found that the levels of atrial natriuretic peptide,creatine kinase,and lactate dehydrogenase(LDH)were higher in patients with chronic KD,when compared to controls,while the level of bradykinin was lower.Furthermore,the PGC-1α,NRF1 and PPARα mRNA levels were higher in patients with KD.The area under the receiver operating characteristic curve and the optimal diagnostic threshold of LDH was 0.937 and 304.0 U/L,respectively.It is noteworthy that the area under the combined receiver operating characteristic curve was larger,when compared to that for LDH detection alone(Z=2.055,P=0.0399).The area under the curve for the“LDH+PPARα”combination was 0.984,with 96.7％sensitivity and 93.0％specificity.Conclusion:The combined detection of LDH and the expression of PPARα can be performed to diagnose the chronic KD.