EPO and Nephropathy: Intriguingly, we noted significantly decreased levels of circulating erythropoietin in Slc7a7 whole-body knockout mice (Fig. 3a), accompanied by reduced Epo gene expression and protein levels in the kidney (Fig. 3b-c), which are typically associated with kidney damage and chronic kidney disease (Batchelor et al. 2020; Weiss et al. 2019).