Effluent CA 125 concentration in chronic peritoneal dialysis patients: influence of PD duration, peritoneal transport and PD regimen

Biocompatibility of a Bicarbonate/Lactate-Buffered PD Fluid Tested with a Double-Chamber Cell Culture System

Objective

In peritoneal dialysis (PD), neutrally buffered PD fluids with lower concentrations of glucose degradation products (GDP) have tested superior to conventional fluids in terms of biocompatibility. However, conventional in vitro studies provoke debate because, due to the lack of subsequent equilibration with the blood, they do not resemble the true intraperitoneal situation of PD.

Methods

We established a double-chamber cell culture system with peritoneal mesothelial cells seeded on top of a permeable membrane, with a physiological buffer below. Thus adequately reflecting the in vivo equilibration pattern, we compared a conventional fluid with a neutral bicarbonate/lactate-buffered PD solution. Using an exchange pattern adapted from an 8-hour continuous ambulatory PD regimen, cell viability was assessed with an MTT assay, and cell function via constitutive and stimulated interleukin (IL)-6 release. As an indicator of potential induction of fibrosis and as a parameter of mesothelial cell integrity, respectively, transforming growth factor-beta 1 (TGF-β1) generation and cancer antigen 125 (CA125) release were measured.

Results

The conventional solution significantly compromised mesothelial cell viability and function in terms of mitochondrial activity ( p < 0.05) and stimulated IL-6 release ( p < 0.05). The bicarbonate/lactate fluid had no effect on cell viability or IL-6 release and turned out to be equivalent to the properties of the growth medium. Whereas lactate-incubated cells did not respond to IL-1β stimulation, bicarbonate/lactate-treated cells adequately increased IL-6 release after stimulation ( p < 0.0005). Release of TGF-β1 and CA125 did not differ between the different fluids and the control.

Conclusions

Due to the sustained equilibration process, the double-chamber cell culture model allows a more realistic insight into mesothelial cell viability and function in terms of PD. As in classic in vitro studies, an adverse effect of conventional PD solutions on mesothelial cells was overt in the present cell culture system. The neutral bicarbonate/lactate-buffered fluid with low GDP content, however, did not interfere with mesothelial cell vitality or function, indicating superior biocompatibility.

The Clinical Usefulness of Peritoneal Dialysis Fluids with Neutral pH and Low Glucose Degradation Product Concentration: An Open Randomized Prospective Trial

Background

Long-term peritoneal dialysis (PD) is associated with the development of various structural and functional changes to the peritoneal membrane when bioincompatible conventional peritoneal dialysis fluids (PDFs) are used. In this study, we looked at patients that were treated with conventional PDFs and then changed to novel biocompatible PDFs with a neutral pH and a low concentration of glucose degradation products (GDPs) to investigate whether this change could result in the arrest or reversal of peritoneal membrane deterioration.

Methods

In an open label, randomized prospective trial, the clinical effects of conventional PDFs and biocompatible PDFs with neutral pH and very low concentration of GDPs were compared in 104 patients equally divided between both study PDFs. Blood and effluent dialysate samples, peritoneal equilibration tests, and adequacy evaluation were undertaken at baseline, 4, 8, and 12 months. The target variables were the ratio of dialysate-to-plasma (D/P) creatinine, peritoneal ultrafiltration, residual renal function, dialysis adequacy indices, and effluent cancer antigen 125 (CA125).

Results

D/P creatinine values were not different in the two groups. Peritoneal ultrafiltration was significantly higher in the low-GDP PDF group than in the conventional PDF group at all follow-up times (4 months: 9.1 ± 4.3 vs 6.0 ± 3.0; 8 months: 8.3 ± 3.4 vs 6.0 ± 3.0; 12 months: 8.9 ± 3.3 vs 6.1 ± 3.3 mL/g dextrose/day; p < 0.05). Peritoneal Kt/V urea values and total weekly Kt/V urea values at 4 months were significantly higher in the low-GDP PDF group than in the conventional PDF group. Residual renal function was not statistically significant. Effluent CA125 levels were significantly higher in the low-GDP PDF group at all follow-up visits (4 months: 37.8 ± 20.8 vs 22.0 ± 9.5; 8 months: 41.2 ± 20.3 vs 25.9 ± 11.3; 12 months: 40.4 ± 21.4 vs 28.6 ± 13.0 U/mL; p < 0.05). Among anuric patients, peritoneal ultrafiltration at 4, 8, and 12 months, total weekly Kt/V at 4 and 8 months, and CA125 levels at all follow-up visits were significantly higher in patients treated with low-GDP PDF than those treated with conventional PDF. However, among anuric patients, D/P creatinine showed no significant differences between the low-GDP PDF group and the conventional PDF group.

Conclusion

The use of biocompatible PDFs with neutral pH and low GDP concentration can contribute to improvement of peritoneal ultrafiltration and peritoneal effluent CA125 level, an indicator of peritoneal membrane integrity in PD patients.

Inflammatory factors for hypoalbuminemia in Japanese peritoneal dialysis patients

AIM

Hypoalbuminaemia is a common complication of peritoneal dialysis (PD), and the leakage of albumin through peritoneal membrane may be a principal reason for hypoalbuminaemia. However, the relationship between peritoneal inflammation, peritoneal transport properties and hypoalbuminaemia has not been fully elucidated.

METHODS

A cross-sectional study was performed on 76 Japanese PD patients who had been using a low-glucose PD solution and icodextrin. Systemic inflammatory markers of C-reactive protein (CRP) and serum interleukin-6 (IL-6), peritoneal effluent markers of dialysate IL-6 and CA125, the dialysate-to-plasma ratio of creatinine (D/Pcr) and the dialysate protein concentration were measured and examined for their relationship with hypoalbuminaemia.

RESULTS

There was a significant positive correlation between serum IL-6 and dialysate IL-6, mean dialysate IL-6 being significantly higher than mean serum IL-6, suggesting that intraperitoneal inflammation was a principal origin of systemic inflammation. Both serum and dialysate IL-6 were significantly correlated with serum albumin (r= -0.25, P<0.05 and r=-0.32, P<0.01, respectively). Dialysate IL-6 was significantly correlated with D/Pcr and the dialysate protein concentration, and there was a significantly positive association between D/Pcr and the dialysate protein concentration. Dialysate CA125, which is argued to be a marker of mesothelial cell mass in this study, was positively correlated with D/Pcr and the dialysate protein concentration. The dialysate protein, dialysate IL-6 and dialysate CA125 all increased according to the peritoneal transport rate defined by D/Pcr. A multiple-regression analysis showed that serum albumin was independently associated with the age, D/Pcr and serum IL-6.

CONCLUSION

Hypoalbuminaemia was attributable to both the increased peritoneal permeability and systemic inflammation, and intraperitoneal inflammation might contribute to developing these complications.

Dialysate cancer antigen 125 in long-term peritoneal dialysis patients

Structural and functional peritoneal membrane changes are associated with long-term peritoneal dialysis. These changes can lead to ultrafiltration failure and peritoneal fibrosis, reducing the efficacy of the peritoneal membrane to remove waste and balance fluid and electrolytes. The loss of mesothelial cells from the basement membrane is one of the major characteristics in peritoneal membrane structural change. Thus, if the reduction of peritoneal mesothelial cell mass in peritoneal dialysis patients is monitored, signs of ultrafiltration failure and peritoneal fibrosis can be detected early. One of biomarkers that can be used to indicate the change in peritoneal mesothelial cell mass is CA125, which is produced by mesothelial cells. In this article, we review the measurement and clinical use of CA125 in peritoneal dialysate effluent. Additionally, we address the data and studies on the association between dialysate CA125 levels and factors related to ultrafiltration failure and peritoneal fibrosis, including the parameters used to monitor the functional status of the peritoneal membrane. Our review shows that dialysate CA125 can be used to evaluate the peritoneal membrane in noninfected patients to predict peritoneal fibrosis, and it can also be used as a biomarker of biocompatible dialysis solutions.

Impact of systemic and local peritoneal inflammation on peritoneal solute transport rate in new peritoneal dialysis patients: a 1-year prospective study

BACKGROUND

The association between peritoneal solute transport rates (PSTRs) and inflammatory markers in patients on peritoneal dialysis (PD) is still under investigation. We aimed to elucidate their relationship during the first year on PD.

METHODS

We performed a prospective observational study with 187 incident PD patients who were treated with either biocompatible solution (BCS) or conventional solution (CS). Peritoneal dialysate effluent (PDE) and blood samples for the markers and the calculation of mass transfer area coefficient of creatinine (MTAC) were performed at 1, 6 and 12 months after commencing PD.

RESULTS

Of the 187 enrolled patients, 110 completed a 1-year study protocol. All PDE markers [interleukin-6 (IL-6), transforming growth factor-beta (TGF-beta), TGF-beta-induced gene-h3 (beta ig-h3), vascular endothelial growth factor (VEGF)] except CA125 increased over time, whereas PSTRs, high-sensitivity C-reactive protein (hs-CRP) and serum IL-6 levels did not change. Serum albumin and log PDE appearance rates (ARs) of IL-6, TGF-beta and CA125 predicted MTAC. The Delta value (12-month minus 1-month) of PDE AR of IL-6 was correlated with those of all other PDE markers. Both 12-month IL-6 and Delta IL-6 ARs in PDE were highest in the upper Delta MTAC tertile. PSTRs in the CS group, unlike BCS, had a tendency to increase over time, demonstrating a time-by-group interaction. Solution type and MTAC were not associated with patient and technique survival.

CONCLUSIONS

The change in PSTR during the first year of PD is related to PDE IL-6 AR, which may represent intraperitoneal inflammation; however, there does not seem to be a close association between PSTR and the degree of systemic inflammation.

Monitoring of the peritoneal membrane

Background. Indirect methods can be used to provide valuable information about peritoneal structure and function for the indirect analysis of peritoneal membrane. Methods. The focus of this paper will be on the commonly available tools for this purpose. First, the value and clinical relevance of CA125 as a marker of mesothelial cell mass in peritoneal effluent will be evaluated. Thereafter, monitoring the peritoneal membrane by using its properties to transport solutes and water will be discussed. Results. The data obtained can be useful for tailoring dialysis adequacy, analysis of clinical problems such as ultrafiltration failure or to predict the development of peritoneal sclerosis.

Screening, diagnosis, and treatment of cancer in long-term dialysis patients

Some have suggested that the American Cancer Society guidelines for cancer screening be applied to patients who are on long-term dialysis and have used cancer screening as a means of assessing delivered preventive health care to patients with ESRD. However, cancer screening is effective only when it leads to survival benefit (usually expressed as days of life saved) without incurring high financial costs. Certain cancers such as human papillomavirus-associated cervical and tongue cancer and urologic malignancies are more common among dialysis patients, yet because the expected remaining lifetime of most dialysis patients is shorter than the time lived to develop malignancy, cancer screening in dialysis patients as applied to the general population is ineffective from the perspective of both cost and survival benefit. Cancer screening in dialysis patients is therefore best provided in an individual patient-focused manner. The occurrence, diagnosis, and treatment of cancer as well as issues related to cancer screening in dialysis patients are discussed.

Dialysate CA125 levels in children on continuous peritoneal dialysis

This prospective study was conducted to assess dialysate cancer antigen 125 (dCA125) levels in pediatric peritoneal dialysis (PD) patients and to investigate whether it exhibits any alterations during or after recovery from peritonitis, and also to analyze the relationships between dCA125 and age, duration of PD treatment, peritonitis incidence, time passed since the last episode of peritonitis, PD prescription parameters, and peritoneal transport parameters. Forty-seven standardized 4-h peritoneal equilibration tests (PET) were performed in 38 children (mean age 11.6+/-4.7 years) on PD (duration 20.9+/-14.3 months). Thirty-two of the patients were in stable condition at the time of PET (stable group). Six patients were included in the study only during a peritonitis episode, and two of the stable patients were reevaluated during a peritonitis episode afterwards (peritonitis group). Seven out of a total of eight patients with acute peritonitis were reexamined after recovery (recovery group). CA125 levels were measured in 188 samples at 0-, 1-, 2-, and 4-h dwells. Peritoneal appearance rates (AR) were calculated. Mean dCA125 (4 h) and AR CA125 values were 5.6+/-5.3 U/ml [median 4.15 U/ml/4 h (range 0.5-25.9)] and 50.1+/-45.6 U/min/1.73 m2[median 37.91 U/ml/1.73 m2 (range 3.61-223.39)]. AR CA125 levels did not correlate with age, PD duration, peritonitis incidence, time passed since the last peritonitis episode, exchange volume used per m2 per day, or peritoneal transport properties in the stable patients' group. Although stable patients using hypertonic PD solutions (n=16) had slightly lower AR CA125 levels (p=0.04), multivariate analysis showed no influence of hypertonic dextrose solutions on mesothelial CA125 secretion (p=0.4). During acute peritonitis, CA125 concentrations showed a reversible threefold increase [AR CA125: stable 37.9 vs. peritonitis 101.2 U/ml/1.73 m2 (p=0.001)]. No difference could be found between the stable group and the recovery group. We conclude that changes in the peritoneal mesothelial cell mass cannot be assessed by determining CA125 in a cross-sectional way and that longitudinal determinations could be more valuable in the follow-up of patients.

Volume Control in Peritoneal Dialysis Patients: Role of New Dialysis Solutions

This paper reviews the most recent clinical data on the volume status of long-term peritoneal dialysis (PD) patients. It appears that many PD patients are volume overloaded, associated with a high prevalence of hypertension and left ventricular hypertrophy. In the presence of the poor results in patients with peritoneal ultrafiltration, the introduction of the polyglucose solution, icodextrin, has ameliorated volume control in some of these patients. In a second part of the review, some of the structural and functional alterations in the peritoneal membrane and the role of glucose degradation products (GDP) in the commonly used dialysates as well as the resulting formation of advanced glycation end products are described. The introduction of low GDP-containing solutions at normal pH has at least in experimental models of PD attenuated the hemodynamic changes observed with the classical solutions. The solutions at normal pH containing either bicarbonate or a mixture of bicarbonate/lactate were clinically associated with less inflow pain.