Background and Aims: Atherosclerosis is accelerated in diabetic patients. Genetic mouse models of atherosclerosis (Ldlr^-/-, ApoE^-/-) require breeding efforts which are time-consuming and costly and often display alterations in lipoprotein metabolism and inflammatory processes. This study aimed to establish a new non-genetic model of inducible metabolic risk factors mimicking hyperlipidemia and hyperglycemia and allowing to detect phenotypic differences dependent on the metabolic stressor(s).
Methods and Results: Wild type mice were injected with gain-of-function PCSK9^D377Y (proprotein convertase subtilisin/kexin type 9) mutant adeno-associated viral particles (AAV) and streptozotocin (STZ) and fed either a high-fat diet (HFD) or high-cholesterol/high fat-diet (Paigen diet, PD) for 12 and 20 weeks. Combined hyperlipidemic and hyperglycemic mice, but not hyperlipidemia alone, display characteristic features of accelerated atherosclerosis characterized by larger and less stable plaques which contained more macrophages (MOMA-2 in diabetic HFD: 27% vs non-diabetic HFD: 19% area/plaque, after 20 weeks, p< 0.05) and less smooth muscle cells (α-SMA in diabetic HFD: 4% vs non-diabetic HFD: 6% area/plaque, after 20 weeks, p< 0.05), on both HFD or PD diet. Diabetic atherosclerotic mice fed a HFD showed 37% plaque area (of total lumen) compared to 16% plaque area in non-diabetic mice after 12 weeks; and 43% (diabetic HFD) vs. 29% area (non-diabetic HFD) after 20 weeks. Differences between the diabetic and non-diabetic atherosclerotic mice were confirmed using RNAseq analysis revealing that significantly more genes are dysregulated in mice with combined hyperlipidemia and hyperglycemia (2341 genes) as compared to the hyperlipidemia only group (424 genes). Those genes were related to pathways regulating inflammation, cellular metabolism and collagen degradation. Mice that were fed a PD showed accelerated atherosclerosis compared to HFD mice indicated by rapid plaque formation already after 8 weeks (diabetic PD: 48% plaque area vs. non-diabetic PD: 30% plaque area), therefore, representing a fast direct inducible hyperglycemic atherosclerosis model.

Conclusion: We established a non-genetic direct inducible mouse model of diabetes-accelerated atherosclerosis allowing comparative analyses of atherosclerosis in diabetic and non-diabetic conditions and revealing novel genetic pathways being involved.