A decreased expression of the fibroblast growth factor (FGF)-23 coreceptor Klotho was postulated as an early alteration in chronic kidney disease mineral and bone disorder, resulting in a compensatory increase in plasma FGF-23 levels. Klotho exists in both membrane-bound and secreted (sKlotho) forms, the latter of which may exert vasculoprotective effects. Here we analyzed plasma sKlotho levels in a large cohort of 312 patients with stage 2-4 chronic kidney disease, and assessed plasma levels of FGF-23, sKlotho, parathyroid hormone, and urinary fractional phosphate excretion. Patients were prospectively followed for an average of 2.2 years for the occurrence of death or initiation of renal replacement therapy. The levels of sKlotho were significantly associated with age, but not with the glomerular filtration rate or other parameters of calcium-phosphate metabolism. Moreover, while patients with high FGF-23 levels faced worst outcome even after adjustment for confounders, we found no prognostic impact of sKlotho. Thus, plasma levels of sKlotho were not related to kidney function and did not predict adverse outcome in patients with chronic kidney disease. Future studies are needed to understand how tissue expression, urinary excretion, and plasma levels of Klotho diverge in progressive chronic kidney disease.

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Background The small number of organ donors forces transplant centres to consider potentially suboptimal kidneys for transplantation. Eurotransplant established an algorithm for rescue allocation (RA) of kidneys repeatedly declined or not allocated within 5 h after procurement. Data on the outcomes and benefits of RA are scarce to date. Methods We conducted a retrospective 8-year analysis of transplant outcomes of RA offers based on our in-house criteria catalogue for acceptance and decline of organs and potential recipients. Results RA donors and recipients were both older compared with standard allocation (SA). RA donors more frequently had a history of hypertension, diabetes or fulfilled expanded criteria donor key parameters. RA recipients had poorer human leucocyte antigen (HLA) matches and longer cold ischaemia times (CITs). However, waiting time was shorter and delayed graft function, primary non-function and biopsy-proven rejections were comparable to SA. Five-year graft and patient survival after RA were similar to SA. In multivariate models accounting for confounding factors, graft survival and mortality after RA and SA were comparable as well. Conclusions Facing relevant comorbidities and rapid deterioration with the risk of being removed from the waiting list, kidney transplantation after RA was identified to allow for earlier transplantation with excellent outcome. Data from this survey propose not to reject categorically organs from multimorbid donors with older age and a history of hypertension or diabetes to aim for the best possible HLA matching and to carefully calculate overall expected CIT.