Abstract 13723: Per2 Mutation Accelerates Diabetic Vascular Dysfunction
Previously, we reported that in diabetes vascular dysfunction is associated with altered circadian release of bone marrow progenitor cells (BMPCs) and bone marrow neuropathy. In this study, we hypothesized that circadian gene (Per2) mutant mice will possess a vascular phenotype similar to diabetes. To assess the presence of accelerated vascular dysfunction we utilized Per2 (Per2tm1Brd/J) or wild type (WT) mice 4 and 12 months of age. Bone marrow (BM) was harvested and BMPCs cells were quantified at time of isolation and proliferation and mRNA expression were subsequently performed. In parallel studies, retinas were processed for mRNA expression of eNOS, plasminogen activator inhibitor (PAI-1), TGFβ1, iNOS by real time quantitative PCR. BM-neuropathy was assessed by staining of femurs with tyrosine hydroxylase (TH) and neurofilament 200 (NF-200) while bone marrow fat content was determined using quantitative magnetic resonance spectroscopy. At both 4 and 12 months, Per2 mutant mice were similar to WT mice in terms of their body weight, blood glucose and HbA1c. At both time points there was a 3- fold decrease in colony forming ability of BMPCs (p<0.05). NO levels in BMPCs revealed 50% decrease (p<0.05) in Per2 mutant mice as compared to WT. Bone marrow fat content of Per2 mutant mice was reduced by 50 % as compared to control animals, but was similar to type 1 diabetic mice. There was gradual decrease (p<0.05) in TH positive nerve processes and NF-200 staining in Per2 mutant mice as compared to WT but similar to diabetic mice. There was gradual decrease in protein and mRNA expression (2 fold, p<0.05) of retinal eNOS at 12 months. Other endothelial function associated genes (VEGFR2, FLT1) were downregulated (1.5-2 fold, p<0.05) in per2 mutant retinas while there was an upregulation of inflammatory and senescent genes (iNOS; 1.5 fold, TGFβ1 2 fold, p<0.05) in retinas of Per2 mutant mice as compared to WT and were similar to diabetic changes. In conclusion Per2 mutant mice possess phenotype similar to diabetes as indicated accelerated vascular dysfunction, bone marrow neuropathy and altered retinal vasculogenic and pro-inflammatory phenotype. Our study validates that circadian alterations of BMPCs play a crucial role in the progression of diabetic complications.
- © 2011 by American Heart Association, Inc.