Soft-tissue calcification is a prominent feature in both chronic kidney disease (CKD) and
experimental Klotho deficiency, but whether Klotho deficiency is responsible for the
calcification in CKD is unknown. Here, wild-type mice with CKD had very low renal, plasma,
and urinary levels of Klotho. In humans, we observed a graded reduction in urinary Klotho
starting at an early stage of CKD and progressing with loss of renal function. Despite
induction of CKD, transgenic mice that overexpressed Klotho had preserved levels of Klotho …