Diabetic Cardiomyopathy and Heart Failure

T1D remains the primary cause of DCM. The long-term goal is to understand the mechanism of T1D leading to DCM. Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays an important role in degrading the low-density lipoprotein receptors (LDLRs) and that increases the circulating LDL cholesterol (LDL-C). Further, PCSK9 increases duringT1D and that, in turn, decreases mitochondrial bioenergetics, transcription factor- mitochondrial (TFAM), and the mitochondrial numbers thus creates an oxidative stress. These changes lead to oxidation of high-density lipoprotein paraoxonase-1 (HDL-Pon1). Because Pon1 hydrolyzes homocysteine (Hcy), the oxidized Pon1 thus causes accumulation of Hcy (i.e. hyperhomocysteinemia; HHcy). Also, the 'metabolic memory' is associated with epigenetic modification (methylation) of genes encoding proteins such as thioredoxin interacting protein (TXNIP). Since methylation/epigenetics inhibits genes, this phenomenon generates even more amounts of Hcy. Investigators have shown that HHcy decreases G-protein coupled receptor (GPCR) Gαs subunit, protein kinase-B (AKT), focal adhesion kinase (FAK) but increases calpain-1, inflammasome and oxidative stress. The central hypothesis is that an increase in PCSK9 causes oxidative stress and decreases TXNIP thus causing oxidation of HDL-Pon1 and subsequent accumulation of Hcy. These alterations lead to decrease in Gαs, AKT, FAK and concomitant increase in PCSK9 and calpain-1 causing metabolic, diastolic, and systolic cardiac dysfunction. Treatment with ketone bodies (the food for mitochondria) will mitigate these changes.