However, the best evidence supporting a role of obesity with the development of hearing impairment comes from in vivo studies Tanigawa et al. 24 found that compared to the wild-type (WT) mice, adiponectin-knockout (APN-KO) mice had exacerbated hearing impairment, particularly in the high frequency range, with reduced cochlear blood flow and capillary density of the stria vascularis. This evidence concerns the gene ANPEP and obesity due to melanocortin 4 receptor deficiency.