KDR and obesity due to melanocortin 4 receptor deficiency: RT-qPCR results showed that, compared with the control group, mRNA expression levels of VEGFA, VEGFR-2, CD31, and SIRT1 were significantly decreased in the obesity group (P < 0.001), while the expression levels of GLUT1, HIF-1α, TNF-α, IL-6, HMGB1, and TLR4 were significantly upregulated (P < 0.01) (Fig 3a).