Peripheral vascular atherosclerosis in a novel PCSK9 gain-of-function mutant Ossabaw miniature pig model

Abstract

Hypercholesterolemia is a major risk factor for atherosclerosis. Remaining challenges in the management of atherosclerosis necessitate development of animal models that mimic human pathophysiology. We characterized a novel mutant pig model with DNA transposition of D374Y gain-of-function (GOF) cDNA of chimp proprotein convertase subtilisin/kexin type-9 (PCSK9), and tested the hypothesis that it would develop peripheral vascular remodeling and target organ injury in the kidney. Wild-type or PCSK9-GOF Ossabaw miniature pigs fed a standard or atherogenic diet (AD) (n = 7 each) were studied in vivo after 3 and 6 months of diet. Single-kidney hemodynamics and function were studied using multidetector computed tomography and kidney oxygenation by blood oxygen level-dependent magnetic resonance imaging. The renal artery was evaluated by intravascular ultrasound, aortic stiffness by multidetector computed tomography, and kidney stiffness by magnetic resonance elastography. Subsequent ex vivo studies included the renal artery endothelial function and morphology of abdominal aorta, renal, and femoral arteries by histology. Compared with wild type, PCSK9-GOF pigs had elevated cholesterol, triglyceride, and blood pressure levels at 3 and 6 months. Kidney stiffness increased in GOF groups, but aortic stiffness only in GOF-AD. Hypoxia, intrarenal fat deposition, oxidative stress, and fibrosis were observed in both GOF groups, whereas kidney function remained unchanged. Peripheral arteries in GOF groups showed medial thickening and development of atheromatous plaques. Renal endothelial function was impaired only in GOF-AD. Therefore, the PCSK9-GOF mutation induces rapid development of atherosclerosis in peripheral vessels of Ossabaw pigs, which is exacerbated by a high-cholesterol diet. This model may be useful for preclinical studies of atherosclerosis.

PCSK9 and lipid metabolism and atherosclerosis: animal models

“…Transgenic Yucatan pigs expressing the human gain of function mutant PCSK9-D374Y in the liver were hyperlipidemic with increased plasma LDL levels on both low fat and high fat, high cholesterol (HFHC) diet and develop atherosclerosis on the HFHC diet [58] . Similar results were obtained by liver expression of the chimpanzee PCSK9-D374Y gain of function mutant in Ossabaw miniature pigs but not Landrace pigs [59] . Atherosclerosis is found in ascending and thoracic aorta, coronary arteries (i.e., left anterior descending and right coronary artery), abdominal aorta, and iliofemoral arteries.…”

Animal Models of Hypertension: A Scientific Statement From the American Heart Association

“…For example, DNA transposition of D374Y gain-of-function cDNA of chimp proprotein convertase subtilisin/kexin type-9 is associated with elevated BP. 202 However, coexisting obesity and hypertension result from the combination of genetic and environmental epigenetic factors. Thus, genetically induced obesity models may not fully address this need.…”

Coming Back to Physiology: Extra Hepatic Functions of Proprotein Convertase Subtilisin/Kexin Type 9

“…Nevertheless, PCSK9 is mainly a modifier of atherosclerosis rather than a trigger itself. When a gain-of-function mutation of PCSK9 was administered into pigs, molecular adaptation was clearly seen but a subsequent physiological measurable difference with endothelial dysfunction required the administration of an atherogenic diet ( Hedayat et al, 2018 ).…”