LEP and obesity due to melanocortin 4 receptor deficiency: Many models of type 2 DM recapitulate the features of HFpEF patients, including leptin-deficient ob/ob mice and the leptin receptor-deficient db/db mice, whose altered leptin homeostasis leads to obesity due to hyperphagia, hyperglycaemia, hyperinsulinaemia, insulin resistance and diabetic complications at different time points [16].