Continuous Ambulatory Dialysis Patients Research Articles

Interaction between Erythropoietin and Peripheral Polymorphonuclear Leukocytes in Continuous Ambulatory Dialysis Patients

The effect of erythropoietin (EPO) on the oxidative stress (OS) and inflammation caused by polymorphonuclear leukocytes (PMNLs) in end-stage renal failure patients undergoing continuous ambulatory peritoneal dialysis (CAPD) was investigated in vivo and in vitro. The studies were performed on isolated PMNLs from peripheral blood of CAPD patients before and following 6 weeks of EPO treatment and from healthy controls. OS was expressed by the rate of superoxide release from phorbol 12-myristate 13-acetate (PMA) stimulated isolated PMNLs and the inflammatory state was evaluated by PMNL counts of the enrolled subjects. Following 6 weeks of EPO treatment in CAPD patients, both the rate of superoxide release from PMNLs and PMNL counts fell significantly when compared with the pretreatment values. In vitro incubation of PMNLs from CAPD patients with increasing amounts of EPO displayed a significant reduction in their rates of superoxide release. EPO, by direct interaction with PMNLs, attenuated their primed state, causing reduction in oxidative stress and inflammation.

Lipid Perxidtion and Antioxidants in Continuous Ambulatory Dialysis Patients

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) concentrations were significantly higher in dialysis patients compared to controls (p less than 0.001) and were significantly higher in CAPD patients compared to hemodialysis patients, p less than 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 (282-480) mumol/L; hemodialysis thiol: 344 (203-468) mumol/L; control thiol: 421.5 (351-504) mumol/L; CAPD SOD: 78.2 (42.4-112.8) u/1/2 mL red cells; hemodialysis SOD: 89.4 (44.6-121.1) u/1/2 mL red cells; control SOD: 96.8 (66.8-153.4) u/1/2 mL red cells). Red cell SOD was significantly negatively correlated with duration of dialysis in CAPD patients (r = -0.683, p less than 0.01). In dialysis patients there is indirect evidence for increased free radical activity, which may be further influenced by the mode of dialysis.

Bactericidal Activity of Peritoneal Macrophages from Continuous Ambulatory Dialysis Patients

A radiometric assay is described for measuring phagocytosis and intracellular killing of Staphylococcus epidermidis by peritoneal cells from continuous ambulatory peritoneal dialysis (CAPD) patients. Using this method it is possible to determine simultaneously and independently, in a single assay, whether peritoneal cells from CAPD patients possess defects in either ingestion or intracellular killing. Assays were performed on peritoneal cells obtained from 28 samples of spent dialysis fluid from CAPD patients. In the majority of cases these cells were able to efficiently phagocytose and kill opsonised Staph. epidermidis, although the degree of intracellular killing was slightly reduced compared with peritoneal cells obtained from eight normal controls undergoing laparoscopy. Overall there was no correlation between the degree of phagocytosis or intracellular killing and susceptibility of patients to peritonitis, although cells from two patients with a high incidence of peritonitis did show abnormally poor ingestion and/or killing. In a number of samples only low numbers of cells (less than 10(6)) were recovered in total from the overnight bags, and there was a significant inverse correlation between the number of cells in the fluid and the length of time on CAPD.