INS and obesity due to melanocortin 4 receptor deficiency: Dysregulated VEGF expression has been closely linked to multiple diseases: in idiopathic pulmonary fibrosis, insufficient angiogenesis accelerates structural remodeling and loss of lung function [7,8]; in early Alzheimer’s disease, reduced cerebrospinal fluid VEGF levels correlate with cognitive decline [9,10]; in ischemic heart disease, inadequate VEGF expression exacerbates myocardial hypoperfusion and increases the risk of ischemic cardiomyopathy [11]; and in obesity, adipose tissue overexpression of VEGF improves insulin sensitivity and alleviates inflammation [12].