*3.5. Uremic Toxins*

Miyata et al. performed a **targeted** metabolomics analysis of six uremic toxins in serum samples by LC-MS/MS. They found that all, *p*-cresyl sulfate, hippurate, indoxyl sulfate, indole-3-acetate, phenylacetate, and phenyl sulfate, were significantly higher in AN patients versus the control group. Moreover, by an **untargeted** approach, they were able to identify increased concentrations of another two toxins in the AN-R group: guanidinosuccinate and N2-phenylacetylglutamine. Although there was no signal of renal damage in the patients, uremic toxins were increased. As some gut microbiota species can produce uremic toxins, it has been suggested that this increase could be potentially linked to gut dysbiosis in AN patients [51].
