For example, it had been found that db/db mice (which lack the functional leptin receptor) did not develop neointimal hyperplasia despite the presence of obesity 22, whereas exogenous administration of leptin promoted experimental lesion formation in injured arteries from wild‐type mice but had no effect on vessels from leptin receptor‐deficient db/db mice 19. Here, LEP is linked to obesity due to melanocortin 4 receptor deficiency.