Clinical significance of fibroblast growth factor-23 and soluble alpha klotho in different stages of chronic kidney disease

Abstract

Most chronic kidney disease (CKD) biomarkers in the current clinical use are not sensitive enough and cannot be used to identify the early stage of the disease. Klotho is a transmembrane protein predominantly expressed in the renal tubules and implicated in managing phosphate homeostasis, together with fibroblast growth factor-23 (FGF-23); a bone-derived protein that increases urinary phosphate excretion. The present study was carried out on 50 patients CKD with different etiologies referred to the Internal Medicine Department and Out Patient Clinic of Tanta University Hospitals and 30 apparently healthy individuals of matched age and sex as a control group. They were subjected to the following assessment: detailed history taking, careful clinical examination, and laboratory investigations, including urea, creatinine, estimated glomerular filtration rate (eGFR), serum electrolytes, urinary albumin, urinary phosphorus (U-Ph), and specific laboratory tests for: Alpha Klotho (α-klotho) and FGF-23 by using ELISA technique. The present study shows that the mean value of serum creatinine, urea, phosphorus, urinary albumin, and FGF-23 were significantly increased, whereas there was a significant decrease in the mean value of eGFR, calcium, and U-Ph in the patients with CKD when compared with control group. Plasma level of serum α-klotho is significantly decreased in all patients with CKD when compared to the control group and there was a significant positive correlation between serum α-klotho level and eGFR, serum calcium level and U-Ph level. Plasma level of serum α-klotho is significantly decreased in all patients with CKD and serum α-klotho can be used as a good marker for early diagnosis and staging of CKD.