Identification of serum biomarkers associated with microvascular functions in a long-term high-fat diet-induced obesity rat model

Serum biomarkers are crucial for identifying complications of obesity. This study evaluated serum levels of leptin, vascular endothelial growth factor (VEGF), myeloperoxidase (MPO), C-reactive protein (CRP), oxidized low-density lipoprotein (OXLDL), low-density lipoprotein (LDL), and other biochemical parameters in a rat model of high-fat diet (HFD)-induced obesity to investigate potential relationships between these biomarkers and microvascular function. Rats in the HFD group were fed a high-fat diet for 23 weeks, whereas control rats received a standard diet. Microvascular function was assessed using the post-occlusive reactive hyperemia (PORH) test; PORH responses were measured in the right forelimbs using laser Doppler flowmetry. Serum samples were then collected to measure the aforementioned biomarkers. Results showed decreased PORH responses in the HFD group, indicating impaired microvascular function. Serum levels of leptin, MPO, CRP, LDL, and OXLDL were significantly higher in the HFD group. Strong correlations were observed between microvascular dysfunction and LDL, OXLDL, MPO, and CRP. No significant changes were found in VEGF or HDL levels. These findings suggest that increased LDL oxidation to OXLDL in obesity contributes to vascular impairment, likely due to increased oxidative stress and inflammation mediated by elevated MPO and CRP. Further research focusing on the roles of LDL, OXLDL, MPO, and CRP may provide deeper insights into the mechanisms underlying microvascular dysfunction in obesity.