Research On The Level Of Plasma Fibroblast Growth Factor-23 And Its Relationship With Atherosclerosis And Cardiac Function In Peritoneal Dialysis Patients

Objective: Fibroblast growth factor 23(FGF-23) is a novel bone-derived phosphate-regulating polypeptide hormone, and the circulating FGF-23 levels increase markedly in peritoneal dialysis patients and are independently associated with increased risk of mortality. Given the fact that cardiovascular disease is the leading cause of death in dialysis patients, the aim of this study was to test if plasma FGF-23 levels might be associated with atherosclerosis and cardiac structure, function in PD patients.Methods: 62 peritoneal dialysis(PD) patients were selected in the PD treatment group. 29 hemodialysis(HD) patients were selected in the HD treatment group, and normal control group was 25 cases. The age and gender among the three groups were matched. Plasma FGF-23 levels were tested by enzyme-linked immunosorbent assay (ELISA). And biochemical parameters were collected,inculding Phosphorus,Calcium,Calcium phosphate product , Parathyroid hormone(PTH).In PD group, carotid artery intima-media thickness(CIMT) was tested by carotid ultrasonography while left ventricular mass index (LVMI) and myocardial performance index(MPI) or Tei index were detected by echocardiography.And PD patients were tested the level of N terminal pro-brain natriuretic peptide(NT-ProBNP) and Cardiac troponin I (cTnI). All statistical analysis was performed with SPSS13.0. P<0.05 was considered statistically significant.Results: 1. Compared with the healthy control group, the level of plasma FGF-23 in PD group (279.92±76.57ng/L) and in HD group (285.02±85.35ng/L) were significantly increased (P<0.05). But there was no significant difference between PD group and HD group (P=0.67). PD patients, whose FGF-23 was between 400 and 600ng/L, had higher serum P, Ca×P, PTH levels than the other two groups (P<0.01). Correlation analysis showed that positive correlation existed between LogFGF-23, serum P (r=0.519,P=0.003), Ca×P (r=0.374,P=0.021) and PTH (r=0.512, P=0.017). Multiple stepwise regression analysis showed that LogFGF-23, serum P (β=0.419, P=0.001) and PTH (β=0.487, P=0.024) were significantly correlated.2. 62 patients of PD group were examined by carotid artery ultrasonography. According to the level of CIMT, the PD group was divided into three groups. The result showed the levels of FGF-23 and serum P were significant differences among the three groups (P <0.05).In the CIMT>1.00mm group, the level of FGF-23 was the highest (346.22±59.02ng/L). Correlation analysis showed that CIMT was positively correlated with LogFGF-23 (r=0.865, P=0.000) and serum P (r=0.594, P=0.028). Multiple stepwise regression analysis showed that LogFGF-23 (β=0.685, P=0.001) and serum P (β=0.561, P=0.023) were obvious correlating factors to CIMT in PD patients.3.62 patients of PD group were examined by echocardiography. Correlation analysis showed that positive correlation existed between LogFGF-23, LVMI (r=0.387, P=0.034) and MPI (r=0.409, P=0.022).Moreover LogFGF-23 with LVMI (β=0.287, P=0.031) and MPI (β=0.301, P=0.026) were significantly correlated. PD patients with LVH had significantly higher levels of FGF-23 (P=0.014), NT-Pro-BNP (P=0.043), cTnI (P=0.037) and serum P (P=0.048) compared with those without LVH. PD patients with Tei>0.47 showed significantly higher levels of FGF-23, NT-Pro-BNP, serum P than those of the Tei index <0.47 gruop. And these were statistically significant (P<0.05). PD patients with P>1.55 mmol/L had higher levels of FGF-23, LVMI, and MPI than those in the group of P<1.55 mmol/L (P<0.05).Conclusions: 1. The levels of Plasma FGF-23 of the HD and PD groups are significant higher than the normal control group, which shows that the renal is the main organ of metabolizing the FGF-23. PD can hardly remove Plasma FGF-23.2. FGF-23 plays some effect on the mineral metabolism of renal.There are positive correlations between LogFGF-23, serum phosphate and serum PTH.These can help to have a stable environment of serum phosphate level and a normal metabolism process.3. LogFGF-23 has a significant positive correlation with CIMT in the PD patients. FGF-23 may play an important role in the occurrence and progress of atherosclerosis in PD patients. 4. LogFGF-23 has a significant positive correlation with LVMI and MPI. FGF-23 may have the effect on the PD patients'cardiac structure and function.