Does Immunosuppressive Treatment Ameliorate Morphology Changes in Encapsulating Peritoneal Sclerosis?

Encapsulating peritoneal sclerosis (EPS) is a clinical syndrome associated with ileus symptoms and irreversible sclerosis of the peritoneal membrane. Inflammation, fibrosis, and neoangiogenesis are the main features of the pathophysiology. No evidence-based therapy is currently available for EPS. In recent years, anti-inflammatory and immunosuppressive (IS) treatment modalities have become more popular.

The aim of the present study was to investigate the effects of various IS treatment strategies—glucocorticosteroid (GC), azathiopurine (AZT), and cyclosporin (CsA)—on regression of EPS.

We divided 52 nonuremic Wistar albino rats into six groups: Control group—2 mL isotonic saline injected intraperitoneally (IP) daily for 3 weeks; CG group—2 mL/200 g 0.1% chlorhexidine gluconate (CG) and 15% ethanol dissolved in saline injected IP daily for 3 weeks; Resting group—CG (weeks 1 – 3), plus peritoneal rest (weeks 4 – 6); Corticosteroid (GC) group—CG (weeks 1 – 3), plus 10 mg/L prednisolone in drinking water (weeks 4 – 6); AZT group—CG (weeks 1 – 3), plus 100 mg/L azathioprine in drinking water (weeks 4 – 6); and CsA group—CG (weeks 1 – 3), plus cyclosporin 7.5 mg/kg by subcutaneous injection daily (weeks 4 – 6).

At the end of the study, under ketamine HCl anesthesia, the rats were humanely killed by bleeding. Parietal peritoneal samples were then taken from same location (away from the injection site) and changes of parietal peritoneum morphology were examined by a single pathologist.

The CG severely disturbed parameters of peritoneal morphology, increasing peritoneal thickness, inflammatory activity, vascularity, and fibrosis score as compared with the Control group ( p < 0.05). No benefit was observed for any parameter in the Resting group as compared withthose parameters in the CG group ( p < 0.05). We observed a lower fibrosis score and less peritoneal thickness in the GC group as compared with the Resting group ( p < 0.05). No beneficial effects of AZT on peritoneal morphology were observed as compared with the effects of peritoneal rest or corticosteroid therapy. Treatment with cyclosporin resulted in more fibrosis, vascularity, and inflammation than was seen with corticosteroid therapy ( p < 0.05).

Immunosuppressive therapies, especially those that are corticosteroid-based, may have therapeutic value in the management of EPS. Patients treated with cyclosporin may have a risk for developing EPS.

Development of a Peritoneal Sclerosis Rat Model Using a Continuous-Infusion Pump

Objective

Encapsulating peritoneal sclerosis (EPS) is a serious complication of continuous ambulatory peritoneal dialysis. Previous studies have created peritoneal sclerosis rat models using daily intraperitoneal injection of chlorhexidine gluconate (CG), but this technique is cumbersome and thickening of the peritoneum makes it difficult to evaluate the injection site. We therefore aimed to make a rat model using a continuous-infusion pump.

Methods

Various concentrations of CG (5%, 8%, 10%, 12%, and 14%) in ethanol were dissolved in saline within the infusion pumps, each of which was placed in the lower abdominal cavity of a male Wister rat. After a peritoneal equilibration test was performed, the rats were sacrificed and the lower anterior parietal and visceral peritoneum was removed. Each excised peritoneum was analyzed by macroscopic and microscopic examinations, including immunohistochemistry for the expression of transforming growth factor-beta 1 (TGF-β1), vascular endothelial growth factor (VEGF), and alpha-smooth muscle actin (αSMA). The results were compared with those of control rats injected with ethanol dissolved in saline within the infusion pump and with no-pump rats.

Results

Two of the 5 rats in the 12% CG group and 3 of the 5 rats in the 14% CG group died of ileus within 14 days. All the rats in the 5%, 8%, and 10% CG groups survived to 28 days. Macroscopic examination in the 10% CG group showed bowel dilatation, bowel adhesion, and bloody ascites, similar to those seen in human EPS patients. All rats in each CG group showed the same extent of thickening of the submesothelial compact zone, proliferation of collagen fibers, and presence of numerous cells and neovascularization. Within same CG groups, an equal degree of thickening was observed at all sites of the peritoneum. TGF-β1, VEGF, and αSMA were highly expressed in the peritoneum of the 10% CG group.

Conclusion

We developed a novel method of creating a peritoneal sclerosis rat model using a continuous-infusion pump. Our technique is simple and highly reproducible, and will be useful in the study of peritoneal sclerosis mechanisms.

Pathogenesis and Treatment of Encapsulating Peritoneal Sclerosis: Basic and Translational Research

Encapsulating peritoneal sclerosis is a devastating condition in long-term peritoneal dialysis patients. Animal models have employed chemical insults to simulate its pathology and have provided insights into its pathophysiology, which appears to include inflammation, angiogenesis, and fibrosis. Monitoring of biomarkers and interruption of molecular pathways have provided potential interventions to slow or prevent the disease process. However, there remain many questions concerning the trigger that alters chronic peritoneal inflammation in peritoneal dialysis to severe sclerosis, peritoneal adhesions, and bowel obstruction. Further advances in therapy will likely require an effective means of an early diagnosis through related biomarkers, which in turn will require further advances in the understanding of the pathogenesis of this disease process.

How Can Genetic Advances Impact on Experimental Models of Encapsulating Peritoneal Sclerosis?

In this review we discuss how animal models have contributed to the understanding of pathological pathways that may be involved in the development of encapsulating peritoneal sclerosis. We review the various interventional procedures that, so far, have ameliorated disease progression in animals. Reviewing advancements in molecular biology and genetic technologies, we discuss how future experimental models may impact our understanding of the pathogenesis and treatment of this rare but complex disease.

Risk Factors for Adverse Outcomes after Peritonitis-Related Technique Failure

Background

Peritonitis is the leading cause of technique failure in peritoneal dialysis (PD) patients. Some patients experience recurrent ascites, encapsulating peritoneal sclerosis (EPS), and even death after catheter removal. Little is known, however, about the risk factors for such complications.

Methods

The study subjects were 117 patients that had their PD catheter removed due to peritonitis between January 2000 and June 2006. Biochemical and clinical data were reviewed retrospectively. Serum C-reactive protein (CRP) and blood and effluent white blood cell counts (WBC) were measured at baseline and at 72 hours of peritonitis. Based on adverse outcomes, patients were classified into 4 groups: non-complication (NC; n = 73), recurrent ascites (A; n = 26), EPS (E; n = 10), and death directly related to peritonitis (D; n = 8).

Results

Age at PD catheter removal was significantly higher in D group compared to NC group (62.0 ± 10.6 vs 51.2 ± 11.5 years, p < 0.05). In addition, mean PD duration was significantly longer in E group compared to NC and A groups (130.5 ± 48.1 vs 58.8 ± 42.4 vs 74.8 ± 47.4 months, p < 0.01). Compared to baseline, effluent WBC was significantly decreased in NC group after 72 hours of peritonitis. In addition, serum CRP level was significantly decreased in NC and A groups, whereas it was significantly increased in D group. Multivariate analyses adjusted for age, PD duration, blood and effluent WBC, serum CRP, and micro-organisms revealed that serum CRP level at 72 hours predicted significantly the development of EPS [odds ratio (OR) 1.15, p < 0.05] and peritonitis-related death (OR 1.18, p < 0.01). In addition, PD duration (per 1 month increase: OR 1.03, p < 0.05) and age at PD catheter removal (per 1 year increase: OR 1.11, p < 0.05) were identified as significant determinants of EPS and peritonitis-related death respectively. Only effluent WBC at 72 hours was significantly associated with the development of ascites (OR 1.27, p < 0.05).

Conclusion

Older patients with long PD duration and those with persistently elevated serum CRP levels were likely to develop complications after peritonitis-related technique failure. Our study suggests that serial measurement of CRP may be helpful in predicting the development of complications after PD catheter removal.

Sclerosing encapsulating peritonitis--a rare complication of ventriculoperitoneal shunts

Sclerosing encapsulating peritonitis (SEP) is a rare cause of bowel obstruction, most commonly associated with chronic ambulatory peritoneal dialysis. It has not previously been reported as a complication of ventriculoperitoneal (VP) shunts. We describe the clinical features of shunt-associated SEP and the important management considerations. Two children presented with small bowel obstruction after long-standing VP shunting of hydrocephalus. Neither had a history of recent shunt infection/revision nor evidence of shunt malfunction. In each case, the bowel was "cocooned" in a fibrous sheath with a notable absence of parietal adhesions. Both children were managed by meticulous adhesiolysis accompanied by shunt exteriorization. Both had prolonged ileus and required total parenteral nutrition. One required further laparotomy at which adhesiolysis was accompanied by irrigation with icodextrin 4% and systemic high-dose methylprednisolone. Weaning of steroids was accompanied by the introduction of azathioprine. A notable feature of intestinal obstruction because of SEP was severe pain despite adequate decompression. The restrictive "cocoon" that envelops the bowel prevents bowel dilatation and accounts for atypical radiologic findings in these cases.

Comparison between the pathology of encapsulating sclerosis and simple sclerosis of the peritoneal membrane in chronic peritoneal dialysis

Reports analyzing the histopathological differences between encapsulating peritoneal sclerosis (EPS) and simple peritoneal sclerosis (non-EPS) and those comparing the pathology of early and late EPS are limited. We present pathological comparisons between EPS and non-EPS, also between the early and late EPS stages. We compared peritoneal membrane (PM) samples (Group B) of 12 EPS patients (Group A) and 23 non-EPS cases regarding; mesothelial loss, submesothelial compact zone degenerated layer and compact zone thicknesses, densities of total and diseased vessels, fibrin stain, new membrane formation and degenerative changes. Group A was subdivided into 7 early (group A1) and 8 late (group A2) EPS cases; we compared both subgroups in the same manner and finally compared groups A1, A2, and B. No differences were found between groups A and B in the incidences of mesothelial detachment, new membrane formation and compact zone degenerative changes between the two groups. Furthermore, there were no differences in compact zone thickness, and vascular densities in the compact zone of respective vascular grade. Whereas, fibrin deposition and thickness of the submesothelial degenerated layer were significantly higher in group A than group B (P = 0.01 and 0.05, respectively), and the thickness of the compact zone was less in group A1 than in group A2 (P = 0.03). Positive fibrin stains and thick degenerative compact zone layers are important pathological findings in EPS. Angiogenesis, vasculopathy, new membrane formation, fibrosis and degenerative changes of the compact zone are not unique characteristics for EPS. Larger size studies are recommended to verify this issue.

Cyclosporin A induces peritoneal fibrosis and angiogenesis during chronic peritoneal exposure to a glucose-based, lactate-buffered dialysis solution in the rat

BACKGROUND/AIMS

Cyclosporin A (CsA) stimulates the development of fibrosis. We investigated whether CsA contributes to peritoneal alterations induced by long-term exposure to dialysis solutions.

METHODS

Ten rats received peritoneal infusion of dialysis solution and oral CsA for 8 weeks. Eight received only the dialysis solution (controls). Peritoneal function was assessed at 8 weeks followed by sacrifice. The number of vessels was counted, fibrosis was assessed and hydroxyproline was determined. PCR was performed for vascular endothelial growth factor (VEGF), connective tissue growth factor (CTGF) and transforming growth factor-beta (TGF-beta).

RESULTS

Histology revealed more fibrosis, hydroxyproline and vessels (thick walled) in CsA-exposed animals. Peritoneal transport was not different. The mRNA content of TGF-beta, CTGF and VEGF was higher in CsA.

CONCLUSION

CsA combined with exposure to dialysis solutions was associated with increased peritoneal fibrosis and angiogenesis.

Various Obstacles to Peritoneal Dialysis Development in Japan: Too Much Money? Too Much Fear?

At 31 December 2005, the number of patients on maintenance dialysis in Japan was 257,765, with 9599 patients having started dialysis that year. Kidney transplant cases in Japan number about 1000 annually. Thus, almost all end-stage renal disease patients in Japan are likely to live on dialysis for the remainder of their lives. For various reasons, peritoneal dialysis has a lower penetration rate among Japanese dialysis patients, and work to educate patients and nephrologists about PD needs to be done.

Sclerosing encapsulating peritonitis (abdominal cocoon) after abdominal hysterectomy

Sclerosing encapsulating peritonitis (SEP) is a poorly understood and rarely documented cause of small bowel obstruction. Although recurrent peritonitis has been reported as the main contributory factor leading to secondary SEP, the pathogenesis of primary (idiopathic) SEP is still uncertain. A 40-year-old woman with a history of total abdominal hysterectomy due to gestational trophoblastic disease presented with progressive lower abdominal pain and abdominal distension. Ultrasonography and contrast-enhanced abdomen-pelvis computed tomography of the abdomen revealed encapsulation of the entire small bowel with a sclerotic capsule. At laparotomy, a fibrous thick capsule encasing small bowel loops was revealed. Extensive adhesiolysis and removal of the capsule from the bowel loops were performed. The patient recovered uneventfully; she was discharged without complications. SEP is a rare cause of small bowel obstruction. We treated a case of abdominal cocoon with intestinal partial obstruction in a woman with a history of abdominal hysterectomy due to gestational trophoblastic disease. Surgical treatment was effective and the patient recovered without complication.

First Use of Tamoxifen in an HIV??Patient with Encapsulating Peritoneal Sclerosis

Encapsulating peritoneal sclerosis (EPS) is a rare but serious life-threatening complication in peritoneal dialysis patients. At present, there is no evidence-based standard therapy for EPS. Tamoxifen has been used and shown good results in non-HIV peritoneal dialysis patients with EPS. We report a case of a patient with HIV treated with antiretroviral therapy (zidovudine, lamivudine and saquinavir) for several years. He had end-stage renal disease and was treated with continuous ambulatory peritoneal dialysis (CAPD). After 11 years on CAPD, he developed EPS and was treated successfully with tamoxifen in combination with corticosteroids. No adverse effects were observed and no changes were noted in CD4 counts or HIV viral load during this therapy. These findings suggest that tamoxifen can be safely given to HIV patients with peritoneal dialysis-related EPS. Nevertheless, caution is required as tamoxifen could interact with certain antiretroviral agents.

Time to reconsider saline as the ideal rinsing solution during abdominal surgery

BACKGROUND

Peritoneal mesothelial cells lining the peritoneal cavity play a primary role in prevention of formation of peritoneal adhesions, which depends mainly on their fibrinolytic activity. During surgical procedures, the abdominal cavity is in most cases rinsed with normal saline solution, which may modify the fibrinolytic activity of the peritoneal mesothelium and predispose to formation of adhesions. The goal of our experiments was to evaluate how normal saline and other solutions affect the fibrinolytic properties of the peritoneal mesothelial cells.

MATERIAL AND METHODS

Experiments were performed on in vitro cultures of human peritoneal mesothelial cells. Mesothelial monolayers were exposed during 6 hours to the following solutions: culture medium (control), .9% NaCl, Hanks solution, Earles solution, new peritoneal dialysis fluid with low glucose degradation products (GDP) concentration (PDF), and peritoneal dialysis fluid with high concentration of GDP (PDF-GDP). Afterwards, morphology of the cells as well as leakage of lactate dehydrogenase (LDH) from their cytosol were evaluated. During the next 24 hours when the cells were cultured in standard medium synthesis of interleukin-6 (IL-6), tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) were studied.

RESULTS

Mesothelial monolayers exposed to .9% NaCl or to PDF-GDP showed destruction of their morphology after 6 hours incubation and in case of PDF-GDP release of LDH from the cytosol was increased by 275% versus the control (P<.05). During subsequent culture of all cells in standard medium, the release of IL-6 was decreased in cases of cells pretreated with .9% NaCl (-58%, P<.05) or PDF-GDP (-93%, P<.001). The release of t-PA was also reduced from cells pretreated with .9% NaCl (-71%, P<.01) or with PDF-GDP (-74%, P<.01) but increased after exposure of these cells to PDF (+35%, P<.05). Statistically significant decrease of PAI-1 synthesis was observed in cells preexposed to .9% NaCl (-69%, P<.01) or to PDF-GDP (-82%, P<.05). When changes in the PAI-1/t-PA ratio were calculated, a strong tendency for increase of that value was seen in cells pretreated with .9% NaCl or Earles salts solution but not with PDF. However, in cases of Hanks solution, a significant increase in the PAI-1/t-PA ratio was observed (+104%, P<.01).

CONCLUSION

Exposure of the peritoneal mesothelial cells to .9% NaCl, Hanks, Earles salts solution, or PDF-GDP results either in reduction of their viability or in loss of their fibrinolytic activity. Peritoneal dialysis fluid with a low content of glucose degradation products appears to be the optimal solution causing the least damage to mesothelial cells and therefore may be the ideal solution for rinsing the abdominal cavity with low risk of inducing deterioration of the mesothelial cells fibrinolytic activity and formation of adhesions. We postulate therefore that such hypertonic peritoneal dialysis fluids should be used not only during peritoneal dialysis but also for rinsing the abdominal cavity during any surgical procedures.

Idiopathic sclerosing encapsulating peritonitis (or abdominal cocoon)

Background

Idiopathic sclerosing encapsulating peritonitis (or abdominal cocoon) is a rare cause of small bowel obstruction, especially in adult population. Diagnosis is usually incidental at laparotomy. We discuss one such rare case, outlining the fact that an intra-operative surprise diagnosis could have been facilitated by previous investigations.

Case presentation

A 56 year-old man presented in A&E department with small bowel ileus. He had a history of 6 similar episodes of small bowel obstruction in the past 4 years, which resolved with conservative treatment. Pre-operative work-up did not reveal any specific etiology. At laparotomy, a fibrous capsule was revealed, in which small bowel loops were encased, with the presence of interloop adhesions. A diagnosis of abdominal cocoon was established and extensive adhesiolysis was performed. The patient had an uneventful recovery and follow-up.

Conclusion

Idiopathic sclerosing encapsulating peritonitis, although rare, may be the cause of a common surgical emergency such as small bowel ileus, especially in cases with attacks of non-strangulating obstruction in the same individual. A high index of clinical suspicion may be generated by the recurrent character of small bowel ileus combined with relevant imaging findings and lack of other plausible etiologies. Clinicians must rigorously pursue a preoperative diagnosis, as it may prevent a "surprise" upon laparotomy and result in proper management.

Prednisolone inhibits hyperosmolarity-induced expression of MCP-1 via NF-κB in peritoneal mesothelial cells

The mechanism of peritoneal fibrosis in patients on continuous ambulatory peritoneal dialysis (CAPD) is poorly elucidated. We investigated the cellular mechanism of high-glucose-induced expression of monocyte chemoattractant protein-1 (MCP-1), which is important in recruiting monocytes into the peritoneum and progression of peritoneal fibrosis, and examined the inhibitory mechanism of glucocorticoids. Rat peritoneal mesothelial cells were cultured in high-glucose-containing medium and then analyzed for phosphorylation levels of p42/44 and p38 mitogen-activated protein (MAP) kinases (MAPK), MAPK or extracellular signal-regulated kinase kinase (MEK)1/2, c-Jun N-terminal kinase (JNK)1/2, and protein kinase C (PKC) by Western blotting. Expression of MCP-1 was examined by reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. DNA-binding activity of nuclear factor (NF)-kappaB was measured by electrophoretic mobility shift assay. High glucose increased MCP-1 mRNA and MCP-1 protein expression. Although glucose increased phosphorylation of MEK1/2, p42/44 MAPK, p38 MAPK, JNK1/2, and PKC, and DNA-binding activity of NF-kappaB, its effect on MCP-1 expression was suppressed only by PKC and NF-kappaB inhibitors. Mannitol caused a similar increase in PKC and NF-kappaB activation and MCP-1 synthesis. Prednisolone increased I-kappaB-alpha expression and inhibited glucose/mannitol-induced NF-kappaB DNA binding and MCP-1 expression without affecting PKC phosphorylation. The inhibitory effects of prednisolone on MCP-1 expression were reversed by mifepristone, a glucocorticoid receptor antagonist. Our results indicate that glucose induces MCP-1 mainly through hyperosmolarity by activating PKC and its downstream NF-kappaB, and that such effect was inhibited by prednisolone, suggesting the efficacy of prednisolone in preventing peritoneal fibrosis in patients on CAPD.

Single-center experience of encapsulating peritoneal sclerosis in patients on peritoneal dialysis for end-stage renal failure

BACKGROUND

Encapsulating peritoneal sclerosis (EPS) is a rare but serious complication in patients undergoing continuous ambulatory peritoneal dialysis (CAPD) or automated peritoneal dialysis (APD). It is characterized by a progressive, intra-abdominal, inflammatory process resulting in sheets of fibrous tissue that cover, bind, and constrict the viscera, thereby compromising the motility and function of the bowel. Although recent therapeutic approaches have been reported with variable success, the ability to detect reliably at an early stage patients at risk for EPS would be beneficial and allow treatment standardization. The aim of this study was to evaluate the clinical features of EPS and identify possible risk factors for its development in CAPD and APD patients.

METHODS

This was a review of all cases of EPS in a single center over the last 5 years.

RESULTS

There were 810 CAPD and APD patients, managed in our program over this period. We identified 27 cases of EPS, giving an overall of 3.3% in this population. The mean duration of CAPD before diagnosis of EPS was 72.6 +/- 39.7 months (range 16-172). Sixteen cases required surgical treatment and were classified as severe; others were treated conservatively (mild to moderate group). Ten patients received tamoxifen treatment with apparent benefit. The overall mortality rate was 29.6%. Eight patients from the severe group and the entire moderate group survived on hemodialysis or transplantation at 48.71 and 27.63 months follow-up, respectively. Peritonitis rates were not different between the 2 groups and peritoneal history was unremarkable compared to overall peritonitis rates in the unit. Data on small solute transport were not available in all patients in this retrospective analysis.

CONCLUSION

EPS is a serious, life-threatening complication of CAPD. Most cases had PD duration of more than 4 years. Careful monitoring by CT scans of the peritoneal membrane in patients beyond 5 years, and early catheter removal in patients with peritoneal thickening should be considered for long-term CAPD patients. Treatment with tamoxifen may be of benefit in these patients.

Restoration of peritoneal integrity after withdrawal of peritoneal dialysis: characteristic features of the patients at risk of encapsulating peritoneal sclerosis

BACKGROUND

The epidemiological characteristics of encapsulating peritoneal sclerosis (EPS), such as its high incidence in patients with long-term peritoneal dialysis (PD) treatment, and the onset of EPS after patients are switched to hemodialysis (HD) may indicate an activated pathological process after PD withdrawal, especially in long-term PD patients. Accordingly, we aimed to observe changes in peritoneal function after the stoppage of PD, and to clarify the characteristic features of the patients at risk of EPS.

METHODS

Thirty-three patients who were switched from continuous ambulatory peritoneal dialysis (CAPD) to HD were enrolled in this trial. Changes in the dialysate/plasma creatinine (D/P Cr) and CA125 levels in the effluent of the peritoneal equilibration test were observed for 6 months. Furthermore, each patient was followed-up for 36 months after PD withdrawal to monitor for the development of EPS.

RESULTS

D/P Cr decreased significantly, while CA125 levels tended to increase. Nine patients developed EPS during the follow-up period and they specifically showed significant increases of D/P Cr levels and significantly lower levels of CA125 at PD withdrawal. The accumulation of high transporters in the EPS group at 0 and 6 months after PD withdrawal was significant.

CONCLUSIONS

Peritoneal recovery may take place after withdrawal from PD treatment and such recover indicated by improvement of transport states and a rise of the CA125 level. The present study revealed that a high-transport state and lack of increase of CA125 in the effluent were associated with EPS development after PD withdrawal. This may suggest that the lack of peritoneal recovery after PD withdrawal is predictive for EPS development.

Impact of a genetic polymorphism of the interleukin-1 receptor antagonist on technique survival in peritoneal dialysis patients

BACKGROUND/AIMS

There is a clear association between one allele of the interleukin-1 receptor-antagonist gene (IL-1RN) and inflammatory diseases in which IL-1 is implicated. We evaluated patient survival and technique survival of peritoneal dialysis (PD) patients, while analyzing independent risk factors, in a PD program. We also tested the association between IL-1RN polymorphism, patient survival and technique survival.

METHODS

We retrospectively evaluated 129 Japanese CAPD patients undergoing initial treatment in eight centers in Japan. Using PCR, IL-1RN genotype and allele frequencies were determined, and clinical and biochemical variables were recorded at the start of PD. The relation of patient survival or technique survival with IL-1RN polymorphism and those variables was analyzed with a multivariate Cox's proportional-hazard model.

RESULTS

The frequencies of IL-1RN*1/IL-1RN*1 and IL-1RN*1/IL-1RN*2 genotypes were 84.5 and 15.5%, respectively. Median patient survival was 37.0 months, and overall patient survival was 92.8 and 87.9% at 2 and 5 years, respectively. Age, cardiovascular disease and serum albumin were found to be independent predictors of patient survival. Median technique survival was 32 months. PD failure occurred in 37 patients, with technique survival rates of 92.0 and 72.7% at 2 and 5 years, respectively. Serum albumin, peritonitis and the presence of the IL-1RN*2 genotype were found to be independent predictors of technique survival.

CONCLUSION

Serum albumin was the strongest predictive factor for mortality and technique failure in PD. Technique failure was also affected by IL-1RN polymorphism in this patient population.

Risk factors for encapsulating peritoneal sclerosis in patients who have experienced peritoneal dialysis treatment

BACKGROUND

The present study was conducted to clarify the clinical risk factors related to the development of encapsulating peritoneal sclerosis (EPS), which is one of the most serious complications in patients undergoing peritoneal dialysis (PD).

METHODS

The records of 78 patients with a history of PD treatment, including 18 with EPS, were retrospectively analyzed (male/female, 51:27; age, 51.8 +/- 11.0 years; PD treatment, 94.1 +/- 42.7 months). The inclusion criteria were: duration of PD more than 24 months; 36-month follow up after discontinuation of PD; available data for dialysate-to-plasma creatinine ratio (D/P Cr), by fast peritoneal equilibration test within 3 months before PD discontinuation; and absence of EPS at PD discontinuation. Analytical parameters included age, sex, underlying renal disease, duration of PD, membrane transport state (higher transporter or lower transporter: D/P cr ratio more than or less than 0.75), number of episodes of peritonitis during PD treatment, performance of peritoneal lavage after PD discontinuation, and reasons for PD withdrawal (ultrafiltration failure, acute peritonitis, social matters).

RESULTS

Significant differences were noted regarding the PD duration, D/P cr, higher membrane transport state, and number of peritonitis episodes during PD. On receiver operating characteristic curves, the cutoff points for EPS were: D/P cr ratio, 0.74; number of peritonitis episodes, 2; and PD duration (months), 115.2. Multivariate analysis, employing the factors age, PD duration, higher membrane transport state, and number of peritonitis episodes, which were selected by stepwise analysis, identified the latter two factors as significant for the development of EPS (odds ratio [OR], 4.0; P = 0.046 and OR, 12.0; P = 0.049, respectively).

CONCLUSIONS

A higher transporter membrane state and the number of peritonitis episodes are factors contributing to the occurrence of EPS in patients who have experienced PD treatment.

Encapsulating peritoneal sclerosis is a separate entity: Con

There is controversy with respect to the issue that encapsulating peritoneal sclerosis (EPS) is a separate entity from simple sclerosis (SS), which is the uniform change of the peritoneum on peritoneal dialysis. These following ideas support the notion that the development of EPS is connected with pathology that is not the same as that responsible for SS: (1) EPS is a rare disorder, (2) certain factors are involved with the etiology, (3) the clinical background of the patients is not uniform, and (4) the histopathological findings of EPS are different from those of SS. There are pitfalls in these concepts and they need be revised. This paper discusses the issue against the idea that EPS is a separate entity, supporting the idea that it has a strong connection with SS in its primary pathophysiology.

Peritoneal fibrosing syndrome: pathogenetic mechanism and current therapeutic strategies

Peritoneal dialysis (PD) has been established as a main renal replacement therapy for approximately 20 years. However, long-term peritoneal exposure to high glucose and other unphysiologic contents in the PD solution may potentiate the development of peritoneal fibrosing syndrome (PFS) in PD patients. PFS is composed of a wide spectrum of peritoneal alterations, which has been observed in PD patients. Molecular studies have shown that the fibrogenic effect of peritoneal mesothelial cells and the accompanying accumulation of extracellular matrix in the peritoneum are key events leading to PFS. In this review, we highlight the impact of PFS and its pathogenetic factors, including bioincompatible PD solution, multidisciplinary inflammatory mediators, and stimulatory cytokines in the peritoneal cavity. Current therapeutic strategies based on both clinical and basic evidence for the prevention or treatment of PFS are also reviewed.

Encapsulating peritoneal sclerosis

Since the first peritoneal dialysis (PD) patients with encapsulating peritoneal sclerosis (EPS) were reported in 1980, EPS has been considered primarily a fatal complication. The incidence of EPS in PD patients has been reported to be from 0.7% to 7.3%, and the rate appears to be higher in patients receiving long-term treatment. Most data from Japan has shown an overall incidence of 2.5% with an evident negative effect of increasing duration of PD, which also augments mortality. Since EPS occurred after withdrawal from PD in more than half of the patients, strict monitoring is necessary when a long-term PD patient is withdrawn from PD. Maintaining patients on standard PD for more than 8 years using conventional solutions is associated with a substantial risk for development of EPS. Appropriate treatment according to the disease stage is most important in EPS treatment. Therefore, when examining a PD patient complaining of gastrointestinal symptoms, the possibility of EPS has to be kept in mind. Basic therapeutic tactics for EPS include appropriate use of steroids. If the state of bowel obstruction persists, laparotomy and enterolysis should be performed to obtain a complete cure. It is now recognized that EPS is not a fatal complication of PD.

Encapsulating peritoneal sclerosis in paediatric peritoneal dialysis patients

Encapsulating peritoneal sclerosis (EPS) is a serious complication of chronic peritoneal dialysis (CPD). In contrast to the adult population, there are few studies regarding EPS in paediatric CPD patients, and the majority of reported patients are from Japan. The aim of the present report is to define the incidence of EPS in our paediatric CPD patients and to describe the clinical and laboratory characteristics. A total of 104 paediatric patients were followed from November 1989 to November 2003 and two were diagnosed as EPS (1.9%). The dialysis periods of these patients were 45 and 53 months with 6 and 8 peritonitis episodes, respectively. Clinical signs of EPS developed 7 and 14 days after the removal of the dialysis catheter, and CPD was replaced by haemodialysis because of persistent peritonitis. One patient was well after surgical management but died 6 months later. The second patient who was treated with prednisolone remained well at 16 months. In conclusion, EPS is a rare but important complication of CPD. We recommend that all patients on CPD who develop ultrafiltration failure be evaluated radiologically for the occurrence of EPS. Management should be tailored to the individual patient.

Simple peritoneal sclerosis and sclerosing peritonitis: related or distinct entities?

AIM

The etiopathogenesis of sclerosing peritonitis is still debated, with some sustaining that it is a rare form of progression of simple peritoneal sclerosis and others that it is a primitive form. The aim of the present research was to clarify this question.

MATERIAL AND METHODS

438 peritoneal biopsies from 253 patients were re-examined. 174 were obtained prior to peritoneal dialysis and 224 after various periods of dialysis. Forty biopsies were from peritoneal dialysis patients who developed sclerosing peritonitis. Peritoneal morphology was studied for signs of transition from simple sclerosis to sclerosing peritonitis.

RESULTS

Evidence was found sustaining the hypothesis that simple sclerosis to sclerosing peritonitis patients have distinct pathologies.

CONCLUSIONS

The results confirm previous observations, excluding the existence of any type of relation between simple peritoneal sclerosis to sclerosing peritonitis.

The pathogenesis and therapeutic option of encapsulating peritoneal sclerosis

Since the first peritoneal dialysis (PD) patients with encapsulating peritoneal sclerosis (EPS) were reported in 1980, EPS has been considered primarily a fatal complication. The incidence of EPS in PD patients has been reported to be from 0.7% to 7.3%, and the rate appears to be higher in patients receiving long-term treatment. Most data from Japan has shown an overall incidence of 2.5% with an evident negative effect of increasing duration of PD, which also augments mortality. Since EPS occurred after withdrawal from PD in more than half of the patients, strict monitoring is necessary when a long-term PD patient is withdrawn from PD. Maintaining patients on standard PD for more than 8 years using conventional solutions is associated with a substantial risk for development of EPS. Appropriate treatment according to the disease stage is most important in EPS treatment. Therefore, when examining a PD patient complaining of gastrointestinal symptoms, the possibility of EPS has to be kept in mind. Basic therapeutic tactics for EPS include an appropriate use of steroids. If the state of bowel obstruction persists, laparotomy and enterolysis should be performed to obtain complete cure. It is now recognized that EPS is not a fatal complication of PD.

Clinical characteristics of dialysis related sclerosing encapsulating peritonitis: multi-center experience in Korea

Sclerosing encapsulating peritonitis (SEP) is a rare but serious complication in patients with continuous ambulatory peritoneal dialysis (CAPD), and is characterized by a progressive, intra-abdominal, inflammatory process resulting in the formation of sheets of new fibrous tissue, which cover, bind, and constrict the viscera, thereby compromising the motility of the bowel. No satisfactory estimate is available on the comparative incidence of dialysis related SEP and the pathogenesis of SEP still remains uncertain. Although recent therapeutic approaches have reported varying degrees of success, an efficient measure to detect, at an early stage, patients at risk for SEP would be beneficial and a standardized treatment regimen to prevent the illness is urgently needed. This study aimed to evaluate the clinical features of SEP and to identify the possible risk factors for the development of SEP in CAPD patients. We retrospectively reviewed by questionnaire SEP cases among CAPD patients from 7 university hospital dialysis centers in Korea, including Yonsei University, Ajou University, Catholic University, Inha University, Kyungpook University, Seoul National University and Soonchunhyang University, from January 1981 to December 2002. Out of a total of 4,290 CAPD patients in these centers, 34 cases developed SEP with an overall prevalence of 0.79%. The male to female ratio was 17:17. The median age of these patients was 44.5 years (range 19-66). The median duration of CAPD before SEP was 64 months (9-144) and 68% of patients (23/34) had been on CAPD for more than 4 years. Peritonitis (including two fungal cases) was the main cause of catheter removal in SEP (27 cases, 79%). Seventy-five percent of the cases (15/20) were administered beta-blocker for a mean duration of 85 months (26-130). Among 10 cases with available peritoneal equilibration test (PET) data, 8 showed high transporter characteristics, and the remaining 2 were high average. Eighteen cases were diagnosed by clinical and radiologic methods, and 16 were surgically diagnosed. Eleven cases were surgically treated and the others were treated conservatively with intermittent total parenteral nutrition (TPN). The overall mortality rate was 24%. SEP is a serious, life threatening complication of CAPD. Most cases had a PD duration of more than 4 years, a history of severe peritonitis, and high transporter characteristics in PET. Therefore, to reduce the incidence of SEP, careful monitoring and treatment, including early catheter removal in patients with severe peritonitis, should be considered for long-term CAPD patients with the above characteristics.

Acute-onset, steroid-sensitive, encapsulating peritoneal sclerosis in a renal transplant recipient

Encapsulating peritoneal sclerosis is a severe complication of peritoneal dialysis. Immunosuppressive drugs have been claimed to be helpful in the treatment of this disease, although the pathophysiological background is poorly understood. In this report, we present a patient with encapsulating peritoneal sclerosis after successful renal transplantation. Maintenance immunosuppressive therapy consisted of mycophenolate mofetil, tacrolimus, and low-dose corticosteroids. The patient was treated successfully with high doses of corticosteroids. A subsequent relapse of the encapsulating peritoneal sclerosis, probably resulting from fast tapering of the corticosteroid dose, responded well to an increase in corticosteroid dose. Our case strongly supports a therapeutic role for high-dose steroids in the treatment of encapsulating peritoneal sclerosis during its initial inflammatory stage.

Sclerosing encapsulating peritonitis as a complication of long-term continuous ambulatory peritoneal dialysis in Korea

Sclerosing encapsulating peritonitis (SEP) is a rare yet serious complication in patients with continuous ambulatory peritoneal dialysis (CAPD). Incidence and prevalence of this syndrome have been defined in some large populations and a few single-centre experiences, but there is no satisfactory estimate of the comparative incidence of dialysis related SEP. The pathogenesis of SEP still remains uncertain, but there could be various causative factors. The diagnosis of SEP remains based on clinical suspicion confirmed with radiologic and/or pathologic findings. The possible variable etiologies and probable distinct pathways leading to this syndrome may make a uniform therapeutic approach unlikely. To determine the prevalence, etiologic factors, clinical features, effect of dialysis duration, and outcome of SEP in Korea, patients undergoing CAPD who developed SEP were retrospectively studied in five University Hospital dialysis centres with large numbers of CAPD patients in Korea. Out of a total 3888 CAPD studied patients between January 1981 to December 2002 in those five medical centres, 31 cases developed SEP with the overall prevalence 0.8%. There were 15 men and 16 women. The mean age of these patients was 44.0 +/- 9.8 years old. The mean duration of CAPD before SEP was 70.3 +/- 41.9 months (range 9-144 months) and 67.8% of patients (21/31) had been on CAPD more than 4 years. Peritonitis, including one fungal peritonitis, was the main cause of SEP in 25 cases (80.6%). Seventy percent of these cases used beta-blocker and the mean duration of the usage was 61.7 +/- 47.6 months. Seven cases were surgically treated and others were treated conservatively with intermittent total parenteral nutrition. The mortality rate was 25.8%. In conclusion, SEP is a serious life threatening complication of CAPD, and most cases had long-term peritoneal dialysis (PD) duration more than 4 years. To reduce the incidence of SEP, careful monitoring may be needed especially in patients with long-term CAPD and peritonitis.

Activation of matrix metalloproteinase-2 causes peritoneal injury during peritoneal dialysis in rats

BACKGROUND

Sclerosing peritonitis (SP) and encapsulating peritoneal sclerosis (EPS) are serious complications of continuous ambulatory peritoneal dialysis. Although we have shown previously that matrix metalloproteinase-2 (MMP-2) is increased in peritoneal injury leading to SP/EPS, most of the MMP-2 in the dialysate drained from the peritoneal cavity was the latent form that was lacking activity. In the present study, we investigated whether MMP-2 causes peritoneal injury.

METHODS

To create an animal model of peritoneal injury, we administered intraperitoneally chlorhexidine gluconate to rats. Dialysate drained from these rats was analysed by gelatin zymography and MMP-2 activity was analysed by an in situ film zymography method. In vitro myofibroblasts were cultured in collagen three-dimensional culture and then MMP-2 in conditioned medium from the culture was analysed by gelatin zymography.

RESULTS

Zymographic analysis revealed that latent form MMP-2 levels were high in the dialysate from peritoneal injury rats, whereas the active form was barely detectable. MMP-2 activity in the peritoneal tissue of the peritoneal injury rats was strongly detected by in situ film zymography. In vitro myofibroblasts were promoted to produce MMP-2 and to activate MMP-2 in collagen three-dimensional culture.

CONCLUSIONS

In the present model, most of the MMP-2 was in the latent form, but activation of MMP-2 was promoted in the peritoneum during peritoneal injury. Activated MMP-2 may be associated with the progression of peritoneal injury.

Ascites from patients with encapsulating peritoneal sclerosis augments NIH/3T3 fibroblast proliferation

Encapsulating peritoneal sclerosis (EPS) remains one of the major causes of dropout in continuous ambulatory peritoneal dialysis by reducing ultrafiltration capacity. To demonstrate whether ascites from patients with EPS (EPS ascites) has fibroblast proliferation activity, we used NIH/3T3 fibroblasts to examine the effects of EPS ascites on fibroblast proliferation activity by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Encapsulating peritoneal sclerosis ascites dose-dependently augmented NIH/3T3 fibroblast proliferation. The protein kinase C inhibitors and the tyrosine kinase inhibitors partially inhibited the stimulatory effects of EPS ascites on fibroblast proliferation activity. In EPS ascites, levels of interleukin (IL)-1beta, IL-6, IL-8, transforming growth factor (TGF)-beta1, hepatocyte growth factor (HGF), and platelet-derived growth factor (PDGF)-AB were elevated. The treatment with IL-1beta, HGF, TGF-beta1, and PDGF-AB alone or in combination at similar concentrations to those in EPS ascites exhibited small but significant fibroblast proliferation activities. We conclude that EPS ascites stimulate NIH/3T3 fibroblast proliferation via protein kinase C and tyrosine kinase. The elevated cytokine and growth factors partly contribute to the EPS ascites-induced fibroblast proliferation.

Buffer transport in peritoneal dialysis

Buffer transport in peritoneal dialysis. The success of peritoneal dialysis as a robust modality of renal replacement therapy has invited a quest for ameliorations in its underlying technology aimed at enhancing patient satisfaction and preserving the central instrument of the therapy, namely the peritoneal membrane. The health and longevity of the membrane have motivated and continue to drive a series of iterative innovations in the composition, methods of production, and delivery of dialysis solutions. It is the purpose of this article to review aspects of these innovations pertaining to buffer composition in dialysis solutions and the peritoneal mechanisms of buffer transport.

Bloody ascites in a patient after transfer from peritoneal dialysis to hemodialysis

A 65-year-old woman with end-stage renal disease (ESRD) presented with bloody ascites. She had been maintained on peritoneal dialysis (PD) for 7 years and had eight episodes of peritonitis. She was eventually transferred to hemodialysis (HD) because of ultrafiltration failure. This was associated with "high" peritoneal transport by peritoneal equilibration test (PET). A period of "peritoneal rest" did not improve PET results. Within a year of transfer to HD, ascites developed, which was hemorrhagic upon evaluation. A computed tomography (CT) scan suggested encapsulating sclerosing peritonitis, which was confirmed upon peritonoscopy. The patient was treated with prednisone and tamoxifen. Encapsulating peritoneal sclerosis (EPS) is a devastating complication of PD. Although it is rare and its development often unpredictable, this case demonstrates several clinical features commonly observed in the condition. These include more than 6 years on PD, a high transporter status, recurrent peritonitis, and the development of blood-stained dialysis effluent (or ascites if PD has been discontinued, as was the case in this patient). The initial presentation is often incipient with vague abdominal pain. Symptoms are progressive, however, and EPS has a high mortality rate, with most patients dying within 1 year of diagnosis, usually from malnutrition and sepsis. Treatment options include systemic immunosuppression and regular peritoneal irrigation after transfer to HD. Response to treatment is more likely to occur in the early inflammatory stage of EPS, when symptoms are nonspecific and imaging is relatively normal. Hence a high degree of suspicion for the diagnosis should be present in patients "at risk" of this condition, as early diagnosis is essential if progressive encapsulation of the abdominal viscera is to be prevented.

High glucose levels inhibit focal adhesion kinase-mediated wound healing of rat peritoneal mesothelial cells

BACKGROUND

The peritoneum is progressively denuded of its mesothelial cell monolayer in patients on continuous ambulatory peritoneal dialysis (CAPD). These alterations of the mesothelium cause membrane dysfunction and progressive peritoneal fibrosis. Integrins regulate cell motility and play an important role in wound healing. We investigated the effects of high glucose on the regeneration process of the peritoneal mesothelial cell monolayer using cultured rat peritoneal mesothelial cells (RPMC).

METHODS

The effects of glucose or mannitol on the regeneration of RPMC and formation of focal adhesions were examined by in vitro wound healing assay and immunocytochemistry, respectively. Activities of focal adhesion kinase (FAK) and its downstream p130Cas were examined by Western blotting. Effects of wild-type and dominant-negative FAK on RPMC migration were examined by a transient transfection assay.

RESULTS

Cell migration over fibronectin (FN) was clearly inhibited in culture media containing high glucose (28 to 140 mmol/L). RPMC formed focal adhesions on FN in the presence of a regular glucose concentration (5.6 mmol/L); however, tyrosine phosphorylation of FAK and p130Cas and formation of focal adhesions observed by FAK and vinculin staining were substantially inhibited by high glucose. Mannitol also induced significant inhibitory effects, but these were milder than those of glucose. Transfection of dominant-negative FAK inhibited cell migration in a regular glucose concentration, whereas overexpression of wild-type FAK abrogated glucose-induced inhibition of cell migration.

CONCLUSIONS

Our results demonstrate that high glucose concentrations as well as high osmolarity inhibit FAK-mediated migration of mesothelial cells, and suggest that dialysates containing high glucose concentrations may cause peritoneal damage by inhibiting wound healing of the mesothelial cell monolayer.

Infections in patients undergoing peritoneal dialysis

Considering experience acquired in the past years, it seems as though physicians have reached a plateau in the frequency of peritonitis. A peritonitis rate of 1 every 2 patient years may be acceptable. Further reduction of this peritonitis rate will require inordinately large efforts on all fronts. One will have to consider what are the acceptable costs and risks of peritonitis in patients on peritoneal dialysis. New developments in catheter technology, improved connections, better understanding of patient selection and training programs, improved diagnostic and therapeutic methods in the management of peritonitis, and understanding of the infectious and immune processes are eagerly awaited developments.