FGF23, αKLOTHO AND VITAMIN D MEDIATED CALCIUM-PHOSPHATE METABOLISM IN HEMODIALYSIS PATIENTS

Background Klotho is a prote˝in that acts as a co-receptor for FGF23. FGF23-Klotho axis has great importance regarding the regulation of mineral metabolism by kidneys. In this study, we analysed FGF23, Klotho, 1,25-dihydroxyvitamin D3, 25-hydroxyvitamin D, parathormone, Calcium and Phosphate levels of haemodialysis patients in order to investigate the nature of the mineral metabolism disruption in chronic kidney diseases. Methods Sixty haemodialysis patients and 34 healthy controls were included in the study. Serum iFGF, cFGF, and soluble Klotho were analysed using ELISA kits. Moreover, 1,25-dihydroxyvitamin D3 was determined using LCMS/MS. Calcium, phosphate, iPTH and 25-hydroxyvitamin D were measured using autoanalyzers. Results In haemodialysis patients, iFGF23, cFGF23, iPTH and P levels were significantly higher, and 1,25-dihydroxyvitamin D3, Klotho and Ca levels were significantly lower compared with the control group. There was no significant difference in the 25-hydroxyvitamin D levels. Conclusions Our study showed that lack of sufficient amounts of Klotho is crucial for mineral metabolism disruptions seen as a complication of chronic kidney diseases. Despite the high levels of the hormone, FGF23 is unable to accomplish its function properly, likely due to deteriorated kidney function in haemodialysis patients.