Association of plasma fibroblast growth factor-23 and alpha-klotho levels with carotid-artery intima media thickness in chronic kidney disease

Association of Plasma Fibroblast Growth Factor-23 and Alpha-Klotho Levels with Carotid-Artery Intima Media Thickness in Chronic Kidney Disease Aim: Chronic kidney disease is an important reason for morbidity and mortality associated with cardiovascular disease. Impaired Ca-P metabolism in patients with chronic kidney disease facilitates vascular injury. FGF-23 and its coreceptor, alpha-klotho are phosphaturic hormones which have important function in regulation of Ca-P balance. The aim of our study is to investigate the association of plasma FGF-23 and alpha-klotho levels with carotid-artery intima media thickness which is an early indicator of atherosclerosis and other biochemical risk factors for shedding light to physiopathology of chronic kidney disease and its complications. Materials and Methods: Study groups consist of 26 control and 72 patients with chronic kidney disease (30 patients in stages 1-3; 42 patients in stages 4-5). Plasma FGF-23 (C-terminal) and alpha-klotho (soluble) levels were analysed by enzyme linked immunosorbent assay (ELISA). Carotid-artery intima media thickness of patients were evaluated with high resolution B-mod ultrasonography. Results: Plasma FGF-23 levels were found significantly higher and alpha-klotho levels were found lower in advanced stages of chronic kidney disease which is associated with impaired renal function and it was considered that these two parameters could be associated with disease progression. Carotid-artery intima media thicknesses of patients were not statistically significant associated with plasma FGF-23 and alpha-klotho levels, but there were statistically significant association of FGF-23 in predialysis patients. There were significant association between high levels of FGF-23 and low levels of alpha-klotho with calcification of carotid-artery and plaque formation. Fractional phosphate excretion were found to be negatively associated with carotid-artery intima media thickness. Conclusion: It has been considered that FGF-23 and alpha-klotho could be important parameters in regulation of mineral metabolism and prognosis of chronic kidney disease. Additionally their effects to cardiovascular system are doubtful. Lack of alpha-klotho levels in patients with stages 4-5 could caused higher levels of plasma FGF-23 in these patients. Fractional phosphate excretion could be an important marker to predict the atherosclerosis in patients with chronic kidney disease. Additional studies are needed to be done in wider populations and more homogenous groups to shed light to this issue. Keywords: Alpha-Klotho, FGF-23, Carotid-Artery Intima Media Thickness, Chronic Kidney Disease.