Peritoneal Dialysis International: Journal of the International Society for Peritoneal Dialysis

To investigate the overall susceptibility of red blood cells (RBC) to lipid peroxidation from patients on continuous ambulatory peritoneal dialysis (CAPD).

The following parameters were measured: RBC malondialdehyde (MDA) production after oxidative stress with H2O2, RBC antioxidant enzymes glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD), and RBC membrane lipid composition. The levels of plasma vitamin E and serum selenium were also as sayed.

Eleven patients on continuous ambulatory peritoneal dialysis. Twenty-one healthy blood donors of similar age were used as normal controls.

The MDA formation after H2O2 stimulation was normal in CAPD patients (0.79±0.1 μmol/gHb versus 0.78±0.1 in the control group). RBC from CAPD patients also showed a normal SOD activity, a more than adequate vitamin E status, and a peculiar pattern of membrane lipids, with reduced polyunsaturated fatty acids (p<0.001) and increased monounsaturated fatty acids (p<0.001). Both RBC GSH-Px activity, a selenium-dependent enzyme, and serum selenium levels were significantly lower in CAPD patients, and a significant positive correlation (r=0.68; p<0.02) between the two parameters was found.

This study found a normal sensitivity to oxidant stress in RBC from a group of CAPD patients, despite an impaired GSH-Px activity. The peculiar lipid pattern of RBC membrane, characterized by reduced PUFA and increased MUFA content, may contribute, in addition to adequate SOD activity and vitamin E status, to normal RBC lipid peroxidation.

To determine the effect of subcutaneous erythropoietin treatment on dialysis efficiency in continuous ambulatory peritoneal dialysis (CAPD) patients. .Design: Dialysis efficiency, platelet and white cell aggregation, and red cell deformability were measured monthly for six months in nine anaemic CAPD patients treated with erythropoietin, and on a single occasion in seven control CAPD patients with intrinsically high haemoglobin concentrations.

Renal dialysis unit.

Nine patients stable on CAPD for a minimum of six months and with haemoglobin concentrations less than 8.5 g/dl were treated with erythropoietin. Seven CAPD patients matched for age and renal function, with haemoglobins greater than 9.0 g/dl served as controls.

Daily peritoneal clearances and net ultrafiltration volumes were unchanged when haematocrit increased from 25.0:1: 2.2% to 36.5:1: 3.5%. Spontaneous whole blood platelet aggregation was significantly increased from week twelve (pre-treatment aggregation 46:I: 23%; 12 weeks: 67:1: 19%, p<0.05; 16 weeks: 64:1: 19%, p<0.01; 20 weeks: 71:1: 16%, p<0.01; 24 weeks: 73:1: 10%, p<0.01).

The increase in haematocrit and platelet aggregation associated with erythropoietin treatment did not affect peritoneal clearances or ultrafiltration capacity.

To determine whether a correlation exists between hemoglobin levels and peritoneal mass transfer or drain volumes in continuous ambulatory peritoneal dialysis (CAPD) patients.

Prospective study of two groups of CAPD patients, identified on the basis of their stable hemoglobin levels. Group A -hemoglobin less than 8.5 g/dL; Group B hemoglobin greater than 10.5 g/dL. Peritoneal mass transfer and drain volumes were measured for each patient, after which a subgroup of Group A was treated with rHuEPO (forming Group C) and measurements repeated once hemoglobin had risen by at least 2.0 g/dL.

Single renal unit of a university teaching hospital. Patients:Twenty-seven patients established on CAPD, selected according to their stable hemoglobin level. Group A -14 patients; Group B -13 patients; Group C (subgroup of A) -8 patients.

Difference between peritoneal mass transfer or drain volume in Group A versus Group B, and in Group C before and after rHuEPO therapy. Serum biochemical parameters in Group C before and after rHuEPO therapy.

No statistically significant differences in any of the parameters measured were found between groups A and B, or before and after rHuEPO therapy in Group C.

Peritoneal transfer of small solutes and water is not influenced by hemoglobin level, and does not change following otherwise effective treatment with rHuEPO.

To assess whether a renal graft outcome is dependent on the modality of dialysis prior to transplantation and to assess risk of peritonitis and catheterrelated problems posttransplantation.

Retrospect analysis of the outcome of a first cadaveric renal transplantation from hemodialysis (HD) and CAPD patients over a ten-year period.

Out of a total of 905 renal transplants over a ten-year period, 699 were first grafts; 500 of these (241 on CAPD, 259 on hemodialysis) were analyzed while the remaining (incomplete data, predialysis, pediatric) were assessed for graft and patient survival only.

Graft and patient survival cases were identical in the two groups (five-year graft survival: CAPD 67%, hemodialysis 66%; five-year patient survival: CAPD 88%, hemodialysis 87%). CAPD post transplant was necessary in 37 patients, while 10 developed peritonitis mostly related to CAPD use and responded to appropriate therapy. Routine catheter removal posttransplant was undertaken between 8 and 12 weeks.

Excellent graft and patient survival is achieved independent of the modality of dialysis prior to transplantation. Peritoneal dialysis can be used postgrafting, but there is a risk of peritonitis, which can be successfully managed with antibiotics and catheter removal. Great care is needed in executing the dialysis and catheter care after transplantation.

Oxidative cell damage due to the production of free radical species has been implicated in the pathogenesis of cardiovascular disease for which dialysis patients are at increased risk. Plasma lipid peroxides (malon-dialdehyde), the antioxidants plasma albumin thiol, and red cell superoxide dismutase (SOD) were therefore measured in 18 patients undergoing continuous ambulatory peritoneal dialysis (CAPD), 20 hemodialysis patients, and 30 normal controls.

Renal dialysis unit.

Malondialdehyde(MDA)concentrationswere significantly higher in dialysis patients compared to controls (p<0.001 ) and were significantly higher in CAPD patients compared to hemodialysis patients, p<0.001 (CAPD, median and range: 11.25 (8.4–15.5) nmol/mL; hemodialysis: 8.75 (7.0–12.6) nmol/mL; controls: 6.65 (5.2–9.6) nmol/mL). Plasma thiol and red cell SOD were significantly lower in dialysis patients compared to controls, but there was no significant difference between CAPD and hemodialysis patients (CAPD thiol: 333.5 (282480) μmol/L; hemodialysis thiol: 344 (203–468) μmol/L; control thiol: 421.5 (351 -504) μmol/L; CAPD SOD: 78.2 (42.4 -112.8) u//2 mL red cells; hemodialysis SOD: 89.4 (44.6–121.1) u//2 mL red cells; control SOD: 96.8 (66.8153.4) u//2 mL red cells). Red cell SOD was significantly negatively correlated with duration of dialysis in CAPD patients (r=-0.683, p<0.01 ).

In dialysis patients there is indirect evidence for increased free radical activity, which may be further influenced by the mode of dialysis.