DLD and diabetic cardiomyopathy: The activation of the citrate cycle (TCA cycle) signaling pathway, pyruvate metabolism, glycolysis/gluconeogenesis and carbon metabolism were all regulated by PDHB, PDHA1, DLAT and DLD; among them, PDHB and PDHA1 were involved in the glucagon signaling pathway, HIF-1 signaling pathway and diabetic cardiomyopathy (Fig. 1E).