Abstract Body: Background. Heart failure with preserved ejection fraction (HFpEF) poses an escalating public health threat, marked by growing incidence and high mortality. In the cardiometabolic phenogroup of HFpEF that includes diabetes and obesity, intramyocardial lipid content is a prognostic indicator of diastolic dysfunction and adverse outcome. Our group recently reported a mouse model of cardiometabolic HFpEF wherein myocardial lipotoxicity was induced by systemic inhibition of lipoprotein lipase (LPL) with Poloxamer 407 (P407) and cardiac overexpression of the LDL receptor (LDLR), conditions that have been documented in clinical HFpEF. The model demonstrates myocardial lipid accumulation, fibrosis, arrhythmia, and diastolic dysfunction. To reproduce this model in large animals we implemented the same protocol in pigs.
Methods. Female Yorkshire swine (~25 Kg) were subjected to one of two protocols including: 1) single intracoronary (i.c.) injection of 10¹³ AAV9-cTnT-LDLR particles and biweekly intraperitoneal (i.p.) P407 at 1g/Kg, (high dose, n=2), or 2) Double i.c. injections of 10¹³ AAV9-cTnT-LDLR particles and biweekly i.p. P407 at 0.25g/Kg) (low dose, n=2). Cardiac structure and function were evaluated by MRI, and hemodynamics measured by PV-Loop at baseline, 4, 8, and 12 weeks. Blood was collected biweekly for complete blood count (CBC), basic biochemistry, and liver and lipid panels. Tissues were collected for protein and histopathological analysis.
Results. In both strategies, the animals developed high LDL-cholesterol and cardiac hypertrophy with preserved EF. High dose P407 led to higher triglycerides, VLDL, HDL, liver injury (ALT > 200U/L), and steatosis at 4 weeks. One of the 2 pigs died at 3 weeks. Low dose P407 and high dose viral particles induced HFpEF at ~12 weeks with increased LV mass, relative wall thickness, end-diastolic pressure, and tau. Serum LDL-C accumulated from an initial value of 161 to 344.5mg/dL at 12 weeks. No significant liver injury was present until week 12 (ALT<88 U/L, AST<59 U/L). Both strategies did not exhibit abnormalities in CBC or other biochemical parameters.
Conclusions. Low dose inhibition of LPL combined with cardiac overexpression of LDLR confers HFpEF in swine.