INS and obesity due to melanocortin 4 receptor deficiency: In conclusion, the results from this study, taken together with our previous results showing an improvement of metabolic parameters when VEGF-C/VEGFR-3 signaling was blocked in obesity, suggest that VEGF-C contributes to the development of insulin resistance and that neutralization of VEGF-C during obesity represents a new and promising strategy to improve insulin sensitivity in the metabolic syndrome.