SPARC expression is markedly up-regulated in AT in obese rodent models and humans with obesity (145, 147, 149), and is positively correlated with metabolic parameters such as fasting insulin and glucose levels, homeostatic model assessment for insulin resistance (HOMA-IR), waist circumference and hsCRP (147). This evidence concerns the gene SPARC and obesity due to melanocortin 4 receptor deficiency.