Ratio of cyclase activating and cyclase inactive parathormone (CAP/CIP) in dialysis patients: correlations with other markers of bone disease.

PURPOSE: We checked correlation of CAP/CIP with osteoprotegrin (OPG), its soluble ligand (OPGL) and routinely measured parameters of bone turnover in patients treated with peritoneal dialysis (PD) and hemodialysis (HD). MATERIAL & METHODS: In 30 patients (22 HD, 8 PD) we determined serum concentrations of intact parathormone (iPTH), CAP, OPG, OPGL, total Ca, inorganic phosphates (Pi), creatinine, urea, total alkaline phosphatase (AP) and blood pH. CIP was calculated by subtraction of CAP from iPTH. Controls (Cs) included 9 healthy persons in whom iPTH, CAP, OPG and OPGL were measured as well as CIP, CAP/CIP and OPGL/OPG were calculated. RESULTS: Differences between HD and PD patients included dialysis duration, OPGL, OPGL/OPG, AP, Pi, Ca and pH. After adjustment to dialysis duration differences in OPGL/OPG, Pi, Ca and pH remained significant. HD patients differed from Cs in terms of iPTH, CAP, CIP, OPGL, OPG and OPGL/OPG. In whole group of patients iPTH, CAP, CIP but not CAP/CIP correlated negatively with OPGL and OPGL/OPG as well as positively with dialysis duration, OPG and AP. CONCLUSIONS: Despite more advanced uremic bone disease in longer dialyzed HD patients than in shorter dialyzed PD ones, CAP/CIP is not different neither between these groups nor Cs persons. CAP/CIP does not seem to be more powerful tool in noninvasive diagnosis of bone disease than iPTH or CAP and CIP alone.

Serum osteoprotegerin level is lower in peritoneal dialysis patients than in hemodialysis ones.

PURPOSE: Osteoprotegrin (OPG) and OPG-ligand are involved in bone turnover induced by parathyroid hormone (PTH) in renal osteodystrophy. We determined serum OPG level in dialysis patients and checked its correlations with other parameters of bone turnover. MATERIAL AND METHODS: Serum level of OPG, PTH, phosphates (Pi), calcium, total alkaline phosphatase (AP) and pH was determined in 29 peritoneal dialysis (PD) patients and 41 hemodialysis (HD) ones. RESULTS: OPG level was lower in PD than HD patients (4.0, 2.1-13.4 pmol/L vs 7.9, 0.9-16.5 pmol/L; p = 0.000) and in both groups it was higher than in controls (2.2, 1.0-3.9 pmol/L; p = 0.000). PD patients had also lower AP (78.0, 34.0-583.0 U/L vs 116.0, 59.0-577.0 U/L; p = 0.000) and Pi (1.4 +/- 0.4 mmol/L vs 3.4 +/- 2.6 mmol/L; p = 0.000) than HD patients, but higher calcium level (2.4 +/- 0.2 mmol/L vs 2.2 +/- 0.3 mmol/L; p = 0.002) and pH (7.412 +/- 0.051 vs 7.326 +/- 0.043; p = 0.000). The only correlation displayed in PD patients for OPG was negative one with pH (r = -0.417, p = 0.038) and in HD patients--positive with Pi (r = 0.548, p = 0.000). OPG level was elevated in 38 HD (92.7%) and in 15 PD (51.7%) patients. There was correlation between serum OPG and AP (r = -0.615, p = 0.033) and calcium (r = 0.575, p = 0.040) in group characterised by normal OPG value. There were no significant correlations in group with elevated OPG level. CONCLUSIONS: Lower serum OPG level in PD patients may be connected with lower activity of osteoclasts and less compensating production of OPG in this group of patients. Lower serum OPG level may contribute to higher serum calcium level in PD patients.

[A role of serum ferritin estimations in continuous ambulatory peritoneal dialysis patients]. / Znaczenie oznaczania stezenia ferrytyny w surowicy chorych leczonych ciagla ambulatoryjna dializa otrzewnowa.

The aim of our studies was to establish an aspect of pathophysiology that is specially indicated by serum ferritin level in continuous ambulatory peritoneal dialysis (CAPD) patients. In 50 CAPD patients serum ferritin level was related to other serum indicators of iron status as well as serum level of C-reactive protein (CRP), peripheral blood morphology (including RBC indices), serum lipid profile, anthropometrical and laboratory parameters of nutritional status, parameters of dialysis adequacy and dietary food intake. In examined CAPD patients serum ferritin concentration was elevated (median 448, range 25-5334 ng/ml). Statistically significant correlations between serum ferritin level and other examined parameters included positive correlation with CRP (r = +0.389) and negative correlation with transferrin (r = -0.462), RBC (r = -0.441), haemoglobin (r = -0.412), haematocrit (r = -0.483), total cholesterol (r = -0.580) and LDL-cholesterol concentration (r = -0.442). There were also positive correlations with daily effluent volume and dietary food intake. Our studies show that in CAPD patients an elevated serum ferritin level is an indicator of inflammatory status, protein malnutrition, and inadequate erythropoiesis, despite normal or nearly normal mean levels of other serum iron parameters. On the other hand, serum ferritin level increases with greater food intake.