ANPEP and Hearing impairment: 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.