We performed metabonomics analysis of the metabolite fraction with GC-TOF-MS (see Supplementary Table S1), and verified that at least two elevated metabolic molecules, stearic acid (a kind of saturated FFAs) and lactate in obesity, were functional stimulators of proinflammatory cytokine and VEGF production in primary chondrocytes (Fig. 2e~l). This evidence concerns the gene VEGFA and obesity due to melanocortin 4 receptor deficiency.