Functional Deterioration of the Peritoneum: Does It Occur in the Absence of Peritonitis?

Peritoneal function in relation to the occurrence of peritonitisand the osmolarity of the dialysate was studied in 72 CAPD patientswith a mean duration of treatment of 16.5±9.0 months(group 1). Data from 24 of these patients, who were on CAPDfor longer than 2 years (average 28.6±4.9), were subjectedto further detailed analysis (group 2). Each group consistedof two subgroups, one of patients who had experienced peritonitisand one of patients who had had no episodes of peritonitis. Results from group 1 revealed that the use of hyperosmolar bagsincreased in parallel with the duration of CAPD treatment evenin the non-peritonitis subgroup, and that peritonitis enhancedthe tendency to use hyper osmolar dialysate solutions. Thisphenomenon was also observed in the peritonitis subgroup ofgroup 2, but was not apparent in the non-peritonitis subgroupof group 2 when examined as a whole: however, individual analysisrevealed that some of them had a similar tendency to use hyperosmolardialysate, as was seen in the peritonitis subgroup. These results comfirm that the peritonitis impairs the ultrafiltrationcapability of the peritoneum. The results also suggest thatthe long-term use of hyperosmolar dialysate may be associatedwith decreased ultrafiltration, hence emphasis should be placedupon the use of hyposmolar dialysate solutions for long-termCAPD.     

Environmental Transmission of Hepatitis B and Hepatitis C Viruses Within the Hemodialysis Unit

Abstract: The hepatitis B virus (HBV) can be transmitted in the dialysis setting through blood transfusions and environmental surfaces. Transfusion related hepatitis C virus (HCV) infection is very well known, but only recently the environmental transmission of this virus was postulated. In order to study the prevalence, mechanisms of transmission, and the ALT patterns of HBV and HCV infections in hemodialysis and CAPD patients before the implementation of HBV vaccination and HCV screening in the blood bank, we conducted a study from January 1987 to January 1990. Sera from 185 hemodialysis and 124 CAPD patients were stored in this period and later analyzed for HBsAg, anti-HBc, anti-HBs, and anti-HCV (second generation ELISA). The prevalence of any HBV marker was 55.7% (103/185) for hemodialysis patients and 31.5% (39/124) for CAPD patients (hemodialysis vs. CAPD, p < 0.001). The prevalence of positive anti-HCV was 35.1% (65/185) for hemodialysis and 33.9% (42/124) for CAPD patients (not significant). There was a significant association between HBV markers positivity and anti-HCV positivity. The multivariate analysis of risk factors revealed an association of the positivity of each virus with the duration of renal replacement therapy (RRT), number of previous blood transfusions, and past history of hemodialysis treatment. Thus, besides the transfusion-related transmission, hemodialysis environmental transmission may also occur for both viruses. The findings of a high prevalence of both viruses and evidence for environmental transmission in the dialysis setting are of major importance for the planning of future preventive measures.     

Antibacterial Activity of the Dialysates and Sera during Treatment with Chemotherapeutic Combinations in Continuous Ambulatory Peritoneal Dialysis (CAPD)

Summary

In everyday clinical practice, different chemotherapeutics are mostly applied intraperitoneally in treating continuous ambulatory peritoneal dialysis (CAPD) peritonitis. Antibacterial activity of the dialysates and sera were studied, according to their bacteriostatic effect after the intraperitoneal and/or peroral administration of chemotherapy. All samples were tested by the two-fold dilution method. We found that the best therapeutical effect is obtained by applying the combination of two compatible chemotherapeutics, in which the first acts in the peritoneal cavity, and the other represents the «pool» of chemotherapeutics forming a barrier to the spreading of bacteria into other distant parts of the body.     

A peritoneal dialysis regimen low in glucose and glucose degradation products results in increased cancer antigen 125 and peritoneal activation

♦ Background: Glucose and glucose degradation products (GDPs) in peritoneal dialysis fluids (PDFs) are both thought to mediate progressive peritoneal worsening.♦ Methods: In a multicenter, prospective, randomized crossover study, incident continuous ambulatory peritoneal dialysis patients were treated either with conventional lactate-buffered PDF (sPD regimen) or with a regimen low in glucose and GDPs: Nutrineal×1, Extraneal×1, and Physioneal×2 (NEPP regimen; all solutions: Baxter Healthcare, Utrecht, Netherlands). After 6 months, patients were switched to the alternative regimen for another 6 months. After 6 weeks of run-in, before the switch, and at the end of the study, 4-hour peritoneal equilibration tests were performed, and overnight effluents were analyzed for cells and biomarkers. Differences between the regimens were assessed by multivariate analysis corrected for time and regimen sequence.♦ Results: The 45 patients who completed the study were equally distributed over both groups. During NEPP treatment, D₄/D₀ glucose was lower (p < 0.01) and D/P creatinine was higher (p = 0.04). In NEPP overnight effluent, mesothelial cells (p < 0.0001), cancer antigen 125 (p < 0.0001), hyaluronan (p < 0.0001), leukocytes (p < 0.001), interleukins 6 (p = 0.001) and 8 (p = 0.0001), and vascular endothelial growth factor (VEGF, p < 0.0001) were increased by a factor of 2 – 3 compared with levels in sPD effluent. The NEPP regimen was associated with higher transport parameters, but that association disappeared after the addition of VEGF to the model. The association between NEPP and higher effluent levels of VEGF could not be attributed to glucose and GDP loads.♦ Conclusions: Study results indicate preservation of the mesothelium and increased peritoneal activation during NEPP treatment. Whether the increase in VEGF reflects an increase in mesothelial cell mass or whether it points to another, undesirable mechanism cannot be determined from the present study. Longitudinal studies are needed to finally evaluate the usefulness of the NEPP regimen for further clinical use.     

Chemokines produced by mesothelial cells: huGRO-α, IP-10, MCP-1 and RANTES

Recently we showed the in vivo relevance of chemokines in cases of bacterial peritonitis in continuous ambulatory peritoneal dialysis (CAPD) patients. Mesothelial cells, the most numerous cells in the peritoneal cavity, are hypothesized to function as a main source of chemokine production. We investigated the time- and dose-dependent expression patterns of four chemokines by mesothelial cells at the mRNA and protein level in response to stimulation with physiological doses of proinflammatory mediators that are present at the site of bacterial inflammation. Besides the chemokines huGRO-α (attractant for neutrophils), MCP-1 and RANTES (monocyte attractants), the expression and production of IP-10 was analysed. Mesothelial cells were cultured and stimulated with either IL-1β, tumour necrosis factor-alpha (TNF-α) or IFN-γ or combinations of these. The time- and dose-dependent mRNA expression of the chemokines was determined by Northern blot analysis and the protein production by ELISA. It was concluded that mesothelial cells could indeed be triggered by the mentioned stimuli to induce mRNA and protein production (huGRO-α and IP-10) or to augment constitutive protein production (MCP-1). However, RANTES mRNA and protein production could only be induced in some cases and only in small amounts. The chemokine response of mesothelial cells was regulated differentially, depending on the stimulus and the chemokine measured. In distinct cases, combination of the stimuli led to synergy in mRNA expression and protein production. The presented in vitro data support our hypothesis that mesothelial cells in vivo are the main source of relevant chemokines in response to proinflammatory mediators, suggesting an important role for mesothelial cells in host defence.     

Impaired outcome of continuous ambulatory peritoneal dialysis in immunosuppressed patients

BACKGROUND.: Although immunodeficiency predisposes to CAPD peritonitis withfungal or unusual organisms, the role of immunosuppression asa predisposing factor for CAPD peritonitis, as well as the outcomeof such episodes, remains uncertain. METHODS.: The incidence, spectrum of infectious organisms, and outcomeof CAPD peritonitis was retrospectively reviewed in 39 immunosuppressedand 146 non-immunosuppressed patients treated with CAPD overthe calendar year 1993. RESULTS.: Immunosuppressed patients were younger (mean 44 vs 57 years,P<0.001) and had an increased incidence of previous transplantation,glomerulonephritis, systemic lupus erythematosus, and vasculitis.Immunosuppressed patients had more episodes of peritonitis (69/39patients vs 99/147, P<0.001), required more frequent hospitaladmission (25/39 vs 33/146, P<0.001), had more days off CAPD(331 vs 242, P< 0.001), and required more laparotomies toremove infected CAPD catheters (11/39 vs 14/146, P<0.01).Immunosuppression was associated with increased infection dueto S. aureus and fungi, which may have contributed towards increasedmorbidity in this group. Current immunosuppression or a recenthistory of immunosuppression appeared to be equally potent riskfactors for infection. There was a trend for the incidence ofinfection to parallel the aggressiveness of immunosuppression. CONCLUSIONS.: Immunosuppression is an important risk factor for CAPD peritonitis.A high index of suspicion for infection and aggressive chemotherapyare mandatory. CAPD may not be the initial therapy of choicein this high-risk group.     

Protein nitrogen appearance in CAPD patients: what is the best formula?

BACKGROUND.: The protein equivalent of nitrogen appearance is an indirectindex commonly used to assess dietary protein intake in patientson CAPD. Moreover it has been suggested that the ratio betweennitrogen appearance and dietary nitrogen intake (fractionalurea synthesis) can predict nitrogen balance in uraemic patients.Several formulae to directly calculate the protein equivalentof nitrogen appearance have been published. It has not beenestablished, however, what formulae give the most appropriateestimate of protein intake and nitrogen appearance. STUDY DESIGN.: Nitrogen balance studies were carried out in seven stable patientson CAPD. All of the patients were receiving a diet whose proteincontent (1.2 g/kg/body wt/day) and calorie content (35 kcal/kg/bodywt/day) were rigorously controlled. Six formulae for calculatingprotein equivalent of nitrogen appearance and nitrogen appearancewere tested and the agreement of the estimating formulae wasevaluated by means of the Bland and Altman method. RESULTS.: Net nitrogen balance was 1.68±0.9 g/N day, protein intake(g/day) 81±19, protein intake (g/kg) 1.05±0.17.Differences in protein equivalent of nitrogen appearance ofup to about 20% were found. The smallest differences betweenprotein equivalent of nitrogen appearance and protein intakewere obtained by the formulae of Bergstrom (1±7 g, limitsof agreement –12 and +15 g) and Blumenkrantz (–2±5g, limits of agreement –11 and +7 g). The formula of Bergstrommost closely estimated nitrogen appearance (–0.35±0.89g). Using such formula, the fractional urea synthesis was 54±12%,giving evidence of positive nitrogen balances. CONCLUSION.: For the routine monitoring of protein equivalent of nitrogenappearance in CAPD patients, we recommend Bergstrom's formulawith the determination of dialysate protein losses.     

Peritoneography and peritoneal computerized tomography: a new approach to non-infectious complications of CAPD.

The introduction of the contrastographic medium (PG) eventually combined with CT scan (PCT) has been used in the study of non-infectious abdominal complications of patients on CAPD. In 27 patients on CAPD from 0 to 98 months we infused, through the peritoneal catheter, 100-200 ml of iopamidol and 500-2000 ml of peritoneal dialysis solution, effecting radiograms in different projections (27 cases), with contiguous axial scannings of 10 mm (8 cases). The information obtained was useful with regard to the therapeutic choices; it clarified the extent, the width, and the anatomical relations of hernias (7/7); the leakage site at the introduction point of the catheter (2/5), and site of surgical treatment (2/5); an inguinal hernia (1/4) and the previousness of the peritoneovaginal duct (3/4) in cases of the genital oedema; a displaced non-opaque catheter (1/4); obstruction of the terminal hole (2/4); wrapping of the omentum in a catheter malfunction (1/4); the presence of scar tissue and pathological recesses in the reduction of ultrafiltration (2/3); and the extension of secondary scar tissue after surgery and before CAPD was started. There were no infective complications or allergic reactions during the research. In conclusion, after reparative surgical intervention, PG and PCT are simple, convenient investigations, with significant diagnostic usefulness, before the introduction of the catheter and/or in cases of complications during CAPD.