Lectin-mediated, nonopsonic phagocytosis of type 1 Escherichia coli by human peritoneal macrophages of uremic patients treated by peritoneal dialysis

Human peritoneal macrophages isolated from uremic patients undergoing peritoneal dialysis bind type 1 fimbriated Escherichia coli in the absence of opsonins. The number of bacteria bound per macrophage was 6.9, as determined by microscopic examination. Methyl alpha-mannoside (0.1 mM) and p-nitrophenyl alpha-mannoside (0.01 mM) inhibited this binding by about 66%. The ability of peritoneal macrophages to bind E. coli in a mannose-specific manner was confirmed in further experiments using an enzyme-linked immunosorbent assay (ELISA) with an antibacterial antibody, radiolabelled E. coli, and counts of colony-forming units (CFU). The number of bacteria bound per macrophage was 7 to 12 in the ELISA and 5.5-8.5 in the CFU assay. Methyl alpha-mannoside caused 70% inhibition of binding in the ELISA and 84% in the CFU assay, whereas p-nitrophenyl alpha-mannoside showed inhibition of 79% and 90%, respectively. Most bound bacteria (76-80%) were subsequently killed. Nonfimbriated E. coli 827 bound poorly to the macrophages (approximately 22%) as compared to that of the fimbriated bacteria. Although this binding was not inhibited by methyl alpha-D-mannoside or p-nitrophenyl alpha-mannoside, the percentage of bacteria killed was similar to that of the fimbriated phenotype. The peritoneal macrophage is thus able to phagocytose E. coli in the absence of opsonins. This may explain the relative rarity of E. coli as an etiologic agent of peritoneal infections in the dialysed patient.     

Antibodies to hepatitis C virus in uremic patients on continuous ambulatory peritoneal dialysis.

The prevalence of antibody to hepatitis C virus (anti-HCV) among 101 uremic patients receiving continuous ambulatory peritoneal dialysis (CAPD) was evaluated using a synthetic peptide-based HCV antibodies enzyme immunoassay. Thirty (29.7%) were found anti-HCV positive. This is significantly higher than 500 unselected paid blood donors (4.2%, P less than 0.0001). Among CAPD patients, anti-HCV positivity was found more frequently in patients who had received frequent and longer duration of hemodialysis previously (40.4% vs. 20.4%, P less than 0.05). These findings suggest that hemodialysis patients have a higher risk of HCV infection. At present, CAPD may be a suitable way to reduce the incidence of HCV infection in uremic patients.     

Effect of monophosphoryl lipid A on the in vitro function of peritoneal leukocytes from uremic patients on continuous ambulatory peritoneal dialysis.

We analyzed the effects of monophosphoryl lipid A (MPL), a relatively nontoxic immunostimulant derived from bacterial endotoxin, on the depressed in vitro immune function of leukocytes derived from six patients undergoing continuous ambulatory peritoneal dialysis and who had histories of recurrent bacterial peritonitis. MPL was also tested for its capacity to stimulate the proliferation of peritoneal fibroblasts, as determined by [3H]thymidine incorporation. In vitro incubation of peritoneal lymphocytes and macrophages (PM phi) with increasing amounts of MPL, up to 5 micrograms/ml, resulted in a dose-dependent enhancement of gamma interferon and interleukin-2 production by peritoneal lymphocytes and interleukin-1 release by PM phi. In vitro incubation of PM phi with MPL also resulted in an increase of PM phi bacterial killing and membrane Fc receptor number, although no change in peritoneal fibroblast proliferation was seen with any of the MPL concentrations tested. These results suggest that the peritoneal leukocyte dysfunction observed in patients undergoing continuous ambulatory peritoneal dialysis and who have high rates of peritonitis may be alleviated, to some degree, by MPL, without directly inducing a potentially deleterious fibrotic lesion.     

MicroRNAs in peritoneal dialysis effluent are promising biomarkers for peritoneal fibrosis in peritoneal dialysis patients

Peritoneal fibrosis is a common complication of long-term peritoneal dialysis, and contributes to encapsulating peritoneal sclerosis and eventually peritoneal ultrafiltration failure, which restricts the wide application of peritoneal dialysis. Therefore, the prevention and treatment of peritoneal fibrosis is important to maintain peritoneal membrane integrity and prolong peritoneal dialysis treatment. Unfortunately, neither specific biomarkers nor effective therapies are available for peritoneal fibrosis in the clinic up to now. Emerging evidence suggests that extracellular microRNAs in body fluids are promising biomarkers for the diagnosis of diseases. microRNAs were reported to be involved in multiple fibrotic diseases and the serum levels of specific microRNAs were correlated with the degree of fibrosis. Moreover, extracellular microRNAs were found in peritoneal fluids and ascites. Based on these findings, here we present our hypothesis that extracellular microRNAs associated with peritoneal epithelial-to-mesenchymal transition and fibrosis could potentially be detected in peritoneal dialysis effluent, and serve as novel biomarkers for early assessment and diagnosis of peritoneal fibrosis.     

Output of peritoneal cells during peritoneal dialysis.

Peritoneal dialysis provides a good source for the collection of macrophages. Six patients with chronic renal failure undergoing peritoneal dialysis for the first time were studied, and maximum cell egress, mostly macrophages, occurred at 24-48 hours and diminished after 48 hours.     

Peritonitis in peritoneal dialysis

Peritonitis, an infectious complication of peritoneal dialysis, continues to account for much of the morbidity associated with this techniques. The clinical presentation and laboratory data used in diagnosis the peritonitis, as well as its differential diagnosis will be reviewed in this article. The distribution of pathogens is an important outcome determinant, Gram-negative infections being associated with greater rates of catheter loss and higher death rates. Among the five routes of peritoneal contamination, intraluminal and periluminal contamination account for most of the infections. Due to the two prevention methods implemented in the care of the PD population, the incidence of peritonitis has decreased over the last two decades. The recommendations for empiric treatment of peritonitis have changed over the years, as more was learnt about antibiotic resistance and drug toxicity. Future research to address enteric peritonitis, as well as biocompatible dialysis solution or biocompatible catheter materials is needed to further reduce the incidence of PD peritonitis.     

Fluid transport in peritoneal dialysis

Standard peritoneal ultrafiltration characteristics in 18 patients undergoing continuous ambulatory peritoneal dialysis (CAPD) were investigated in a total of 21 single dwell studies of 6 h duration with 2 L of 3.86% glucose dialysis fluid. Intraperitoneal dialysate volumes were determined using radioiodinated serum albumin (RISA). Calculations were based on a novel mathematical method in which RISA elimination from the peritoneal cavity was taken into account. The RISA elimination rate, KE, was calculated as 2.1 +/- 0.5 ml/min. The true dialysate volume after 360 min (2957 +/- 196 ml) was on the average 28% lower than the volume (3737 +/- 260 ml) calculated without correction for the elimination of RISA. The mean maximum true volume plus sampling losses was 3255 ml at 240 min corresponding to a mean ultrafiltration of 762 ml between 3 min and 240 min. Our method of peritoneal volume determination proved to be useful for clinical investigations. The present study demonstrates that CAPD patients, without any major ultrafiltration problems, exhibit relatively small interpatient variations in their peritoneal volume over time curve.     

Osmotic agents for peritoneal dialysis

Glucose has more advantages than drawbacks and is now the sole agent used in clinical practice. Yet there is interest in finding a substitute for glucose as an osmotic agent in peritoneal dialysis solution. Work has identified several promising agents such as albumin, amino acids, gelatin and glycerol but it appears that every one of them, including glucose, would be useful for a short-dwell or for a long-dwell exchange but not for both. Some of them, such as albumin and the amino acids, are close to being an ideal osmotic agent but are prohibitively costly to manufacture. We predict that interest in the future will focus on dialysis solutions containing a mixture of osmotic agents. Such a solution would be acceptable for both short and long-dwell exchanges. It will have a sufficiently low concentration of different agents to minimize toxicity and long-term undesirable side effects. We expect that solutions will be available to better meet patients needs in the near future.     

Extension of the life of nephrectomized rabbits by peritoneal dialysis

Summary A method is described of substituting renal excretory function by peritoneal dialysis; the survival time of nephrectomized rabbits was increased three times.(Presented by Active Member AMN SSSR V. V. Parin) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 53, No. 2, pp. 125–127, February, 1962     

Mortality in peritoneal dialysis patients

The incidence of end-stage renal disease is growing. Mortality remains high, despite improvements in care. Much of this can be explained by the presence of cardiovascular disease and other co-morbid conditions that are present at the start of dialysis. However, the dialysis treatment itself may exacerbate these conditions, and dialysis related factors such as adequacy, cytokine production, and dialysis-related infections are important factors in survival. Early studies reported similar or better survival on peritoneal dialysis (compared with hemodialysis), although more recent studies have questioned this finding. This review summarizes the information on mortality in peritoneal dialysis patients.     

A device for peritoneal dialysis

Conclusions 1. The siphon principle used in the hydrodynamic system of the PD device ensures ease of operation and reliability and rules out barotraumas of the organs of the abdominal cavity.2. Through the use of the elastic containers in the hydrodynamic system the need for contact of DS with the atmosphere is not required.3. The principle of on-site production of DS makes infection less probable and requires no great expense.4. The unit for dosing of DS components, as designed on the basis of elastic containers placed in rigid chambers with variable volume, is reliable, provides for long-term service and the ability to program the DS concentration parameters, and permits the preparation of hemofiltration substitute and bicarbonate solutions for any purpose.5. A multipatient SCPD meets the needs of a large group of patients with uremia, but individual devices are preferable for nonstandard cases.Department of Hemodialysis and Kidney Transplantation, Republic Clinic, Kishinev. Scientific Research Institute for Transplantation and Artificial Organs, Moscow. Translated from Meditsinskaya Tekhnika, No. 2, pp. 33–34, March–April, 1992.