Klotho, the elusive kidney-derived anti-ageing factor

Chronic kidney disease (CKD) is one of the fastest growing causes of death worldwide. Only early diagnosis will allow prevention of both CKD progression and the negative impact of CKD on all-cause and cardiovascular mortality. Klotho is a protein produced by the kidneys that has anti-ageing and phosphaturic properties, preventing excess positive phosphate balance. There is evidence that Klotho downregulation is one of the earliest consequences of kidney injury. Thus the development of reliable assays to monitor Klotho levels may allow an early diagnosis of CKD and monitoring the impact of therapies aimed at preserving Klotho expression or at preventing CKD progression. However, the performance of Klotho assays has been suboptimal so far. In this issue of Clinical Kidney Journal, Neyra et al. explore methods to improve the reliability of Klotho assays.