Introduction Metformin is the most prescribed medication in Type 2 Diabetes(T2D). Metformin has shown to decrease mean platelet volume, with promising antiplatelet effects. High doses of Metformin have also been associated with hypercoagulation. We hypothesize that Metformin will protect T2D mice from occlusive arterial thrombus formation by altering platelet activation and mitochondrial bioenergetics. Methods T2D was developed by low dose of Streptozotocin, non-T2D (healthy) mice are controls. Either vehicle or Metformin was administered twice daily via oral gavage for 7-days. Ferric chloride (FeCl3) arterial thrombosis and tail bleeding time were performed. Whole blood aggregometry, platelet activation/adhesion and mitochondrial bioenergetics were evaluated. Results Metformin decreased susceptibility of T2D mice to arterial thrombosis. Platelet bioenergetics show T2D mice have increased platelet mitochondrial respiration, but no differences were observed with Metformin treatment. Metformin modulated ADP-dependent expression of markers of platelet activation/adhesion. Metformin in non-T2D mice shortens bleeding time and increased susceptibility to thrombotic occlusion. Metformin increased platelet mitochondrial maximal respiration and spare respiratory capacity uniquely in non-T2D mice. Conclusion Metformin regulates platelet bioenergetics and ADP-mediated platelet function in T2D mice which attenuates susceptibility to arterial thrombosis. Future studies will evaluate clinically relevant doses of Metformin that regulates thrombotic function in diabetic platelets.
Our group has identified smooth muscle cell targeted deficiency of LDL Receptor related protein 1 (LRP1), smLRP1‐/‐, resulting in accelerated aortic atherosclerosis. Activation of cytoplasmic phospholipase A2 (cPLA2) in these mice leaded to abolished LXRa/ABCA1 in vascular smooth muscle cells (VSMCs) and increased intracellular cholesterol accumulation. Based on our previous work we hypothesized that deficiency of cPLA2 would impede atherogenesis in the smLRP1‐/‐ mouse model. Methods: Adult male smLRP1‐/‐;cPLA2‐/‐;LDLR‐/‐ (Triple knockout) mice were placed on a high cholesterol diet (HCD) for 16 weeks and compared to age‐ and diet‐ matched sibling control smLRP1+/+;cPLA2‐/‐;LDLR‐/‐ (Double KO) mice. Primary VSMC were explanted for in vitro migration, cell viability and proliferation studies when stimulated w/PDGF‐BB. Histologic analysis was performed using en face whole aorta Oil red O (ORO) staining, as well as cross‐sectional analysis of the aortic root with ORO, Picro Sirius Red, Alizarin Red and immunofluorescence. Immunoblot protein analysis was performed using lysed whole aortas. Data is represented as mean±SEM. Statistical analysis was performed using one‐ and two‐way ANOVA with Tukey's correction. Results: Triple KO VSMC have decreased viable and proliferating cells but increased VSMC migration both compared to unstimulated and double KO controls. En face ORO analysis revealed increased lipid accumulation in Triple Knockout mice as compared to controls (60+/‐3% vs 13+/‐2%, p<0.001) (Figure 1). Uniquely, Triple knockout mice develop extensive necrotic cores and thin fibrous caps in atherosclerotic lesions in the aortic root (Figure 1). We found increased LXRa aggregates in triple KO mice and paradoxically ABCA1 is increased compared to controls observed by immunoblot and immunofluorescence tissue analysis of VSMC atherosclerotic tissues. Conclusions: Deficiency of cPLA2 in the smLRP1‐/‐ mouse model induces LXRa increase and aggregation leading to rescue of ABCA1, but unexpectedly increases VSMC dysfunction and lipid accumulation within the plaque and generates more vulnerable plaque. Future studies will underpin the exact molecular mechanism that guide severe disease development in our Triple knockout mice via regulation of ABCA1.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.