Encapsulating peritoneal sclerosis: Your questions answered

Encapsulating peritoneal sclerosis (EPS) is a clinical syndrome hallmarked by the formation of a fibrous cocoon encapsulating the bowel resulting in morbidity and mortality. EPS is most frequently associated with peritoneal dialysis (PD), particularly with its discontinuation. While EPS is one of the most feared complications of PD, the majority of patients receiving PD will not go on to develop EPS. Risk factors for development include time on PD, some types of peritonitis and discontinuation of PD. Owing to its rarity, much of the knowledge of EPS comes from case series and registries and treatments are extrapolated from low-quality evidence. Malnutrition is a significant driver of mortality, and nutritional support is critical in management. We present a case of EPS and frequently asked questions including the definition, diagnosis, epidemiology, pathophysiology, risk factors, role of infection, management and roles of nutrition and surgery.

Effect of bevacizumab and everolimus combination treatment on peritoneal sclerosis in an experimental rat model

The aim of this study was to investigate whether bevacizumab and everolimus combination therapy is superior to bevacizumab treatment alone as a treatment for peritoneal sclerosis. Forty Wistar albino rats were divided into five equal groups. The control group received isotonic saline solution (2 mL/day) intraperitoneal (IP) daily for 3 weeks. The CG group received 2 mL 0.1% chlorhexidine gluconate (CG) and 15% ethanol dissolved in saline IP daily for 3 weeks. Peritoneal tissue samples were taken at the end of 3 weeks. The resting group received CG (weeks 0-3), plus isotonic saline solution (2 mL/day) IP daily and tap water (2 mL/day) via a feeding tube daily (weeks 3-6).The bevacizumab group received CG (weeks 1-3) plus bevacizumab at 2.5 mg/kg/day (2 mL) IP daily and tap water (2 mL/day) via a feeding tube daily (weeks 3-6). The bevacizumab+everolimus group received CG (weeks 1-3) plus bevacizumab at 2.5 mg/kg/day (2 mL) IP daily and everolimus at 0.3 mg/kg/day (2 mL) via a feeding tube daily (weeks 3-6). Peritoneal tissue samples were taken from these three groups at the end of 6 weeks and were examined after staining with hematoxylin-eosin and Masson's trichrome. Inflammation, vasculopathy, fibrosis, and peritoneal thickness were evaluated under light microscopy. The samples were also stained with anti-TGF-β and anti-MMP-2. Inflammation and vasculopathy scores were significantly decreased in the VEGF-i group compared to the CG group. The addition of everolimus to VEGF-i showed significantly lower inflammation, vasculopathy, fibrosis scores, and an evident decrease in peritoneal thickening (respectively, 2.29 ± 0.76 vs 0.57 ± 0.53, P = .003; 2.71 ± 0.76 vs 1.43 ± 0.53, P = .008; 2.57 ± 0.79 vs 1.57 ± 0.79, P = .04; 247.5 ± 136.1 vs 84.5 ± 48.6, P = .048). MMP-2 levels were lower in the combination group compared to the resting group (2.63 ± 0.74 vs 1.86 ± 0.38, P = .019). The study results demonstrated that bevacizumab and everolimus combination therapy was more effective than bevacizumab therapy alone.

Encapsulating Peritoneal Sclerosis: Pathophysiology and Current Treatment Options

Encapsulating peritoneal sclerosis (EPS) is a life-threatening complication of long-term peritoneal dialysis (PD), which may even occur after patients have switched to hemodialysis (HD) or undergone kidney transplantation. The incidence of EPS varies across the globe and increases with PD vintage. Causative factors are the chronic exposure to bioincompatible PD solutions, which cause long-term modifications of the peritoneum, a high peritoneal transporter status involving high glucose concentrations, peritonitis episodes, and smoldering peritoneal inflammation. Additional potential causes are predisposing genetic factors and some medications. Clinical symptoms comprise signs of intestinal obstruction and a high peritoneal transporter status with incipient ultrafiltration failure. In radiological, macro-, and microscopic studies, a massively fibrotic and calcified peritoneum enclosed the intestine and parietal wall in such cases. Empirical treatments commonly used are corticosteroids and tamoxifen, which has fibrinolytic properties. Immunosuppressants like azathioprine, mycophenolate mofetil, or mTOR inhibitors may also help with reducing inflammation, fibrin deposition, and collagen synthesis and maturation. In animal studies, N-acetylcysteine, colchicine, rosiglitazone, thalidomide, and renin-angiotensin system (RAS) inhibitors yielded promising results. Surgical treatment has mainly been performed in severe cases of intestinal obstruction, with varying results. Mortality rates are still 25–55% in adults and about 14% in children. To reduce the incidence of EPS and improve the outcome of this devastating complication of chronic PD, vigorous consideration of the risk factors, early diagnosis, and timely discontinuation of PD and therapeutic interventions are mandatory, even though these are merely based on empirical evidence.

Strategies for preventing peritoneal fibrosis in peritoneal dialysis patients: new insights based on peritoneal inflammation and angiogenesis

Peritoneal dialysis (PD) is an established form of renal replacement therapy. Long-term PD leads to morphologic and functional changes to the peritoneal membrane (PM), which is defined as peritoneal fibrosis, a known cause of loss of peritoneal ultrafiltration capacity. Inflammation and angiogenesis are key events during the pathogenesis of peritoneal fibrosis. This review discusses the pathophysiology of peritoneal fibrosis and recent research progress on key fibrogenic molecular mechanisms in peritoneal inflammation and angiogenesis, including Toll-like receptor ligand-mediated, NOD-like receptor protein 3/interleukin-1β, vascular endothelial growth factor, and angiopoietin-2/Tie2 signaling pathways. Furthermore, novel strategies targeting peritoneal inflammation and angiogenesis to preserve the PM are discussed in depth.

Abatacept as a therapeutic option in the treatment of encapsulated peritoneal sclerosis: an experimental rat model

PURPOSE

Encapsulated peritoneal sclerosis (EPS) is a rare complication of long-term peritoneal dialysis (PD) and is usually associated with mortality. Inflammation is a leading factor for developing EPS. This study aimed to investigate the effect of abatacept on peritoneal fibrosis and inflammation using the EPS rat model.

METHODS

Twenty-four Wistar albino rats were randomly divided into four equal groups. Group I (control group) was administered isotonic saline (IS) via the intraperitoneal (ip) route during weeks 0-3. Chlorhexidine gluconate (CG) ip was administered to group II (CG group) during weeks 0-3. Group III (CG + IS group) received CG for the first 21 days and IS solution for the following 3 weeks. Group IV (abatacept group) received CG during weeks 0-3, and subsequently, 50 mcg/day abatacept during weeks 4-6. Peritoneal thickness, fibrosis, and inflammation were examined using light microscopy. Expressions of matrix metalloproteinase-2 (MMP-2) and transforming growth factor-beta 1 (TGF-β1) were detected by immunohistochemical staining.

RESULTS

Lesser peritoneal thickness and lower inflammation score were observed in the abatacept group than in the CG and CG + IS groups (p < 0.05). Furthermore, the abatacept group had a lower fibrosis score than the CG + IS group (p < 0.05). MMP-2 and TGF-β1 scores were lower in the abatacept group than in the CG + IS group (p < 0.05).

CONCLUSIONS

The results revealed that abatacept had a histopathological beneficial effect on peritoneal fibrosis, inflammation, MMP-2, and TGF-β1 scores, which were induced by CG. Abatacept could be a new therapeutic option for treating EPS.

mTOR inhibitors for medical treatment of post-transplantation encapsulating peritoneal sclerosis: a favourable single center experience

BACKGROUND

Encapsulating peritoneal sclerosis (EPS) is a serious complication in patients on peritoneal dialysis (PD) causing intestinal obstruction. Two different forms of EPS are reported: the classical one observed in patients on PD, and post-transplantation EPS (PostTx-EPS). The first-line therapy of classical and PostTx-EPS remains surgical treatment, but for both the complication rate and mortality are high. Recently, a few cases of EPS were successfully treated with inhibitors of mammalian target of rapamycin (mTORi). The aim of this study was to evaluate PostTx-EPS outcome in our patients, focusing on the potential benefit of mTORi treatment.

METHODS

We performed a retrospective analysis on 1,048 kidney transplanted patients at our center between 11/2001 and 12/2011.

RESULTS

In the 226 patients treated with PD at any time before grafting, we found 10 cases of PostTx-EPS (prevalence 4.4%). The mean age was 54.9 years (26-69), with a mean time on PD of 83.1 months (33-156). The interval between kidney transplant and EPS diagnosis was 10.5 months (4-18.9). Five of the ten patients were treated after the diagnosis with mTORi, with a favorable outcome in 4/5 cases. This result was substantially independent of surgical and steroid therapy, performed in 9/10 and 10/10 patients respectively.

CONCLUSION

EPS is a serious complication but susceptible to improvement if early diagnosed. mTORi represent a useful option for EPS treatment. We too suggest adopting an immunosuppressive protocol based on mTORi, mycophenolate mofetil and steroids in order to prevent PostTx-EPS in transplanted patients at high risk.

Encapsulating peritoneal sclerosis-a rare but devastating peritoneal disease

Encapsulating peritoneal sclerosis (EPS) is a devastating but, fortunately, rare complication of long-term peritoneal dialysis. The disease is associated with extensive thickening and fibrosis of the peritoneum resulting in the formation of a fibrous cocoon encapsulating the bowel leading to intestinal obstruction. The incidence of EPS ranges between 0.7 and 3.3% and increases with duration of peritoneal dialysis therapy. Dialysis fluid is hyperosmotic, hyperglycemic, and acidic causing chronic injury and inflammation in the peritoneum with loss of mesothelium and extensive tissue fibrosis. The pathogenesis of EPS, however, still remains uncertain, although a widely accepted hypothesis is the "two-hit theory," where, the first hit is chronic peritoneal membrane injury from long standing peritoneal dialysis followed by a second hit such as an episode of peritonitis, genetic predisposition and/or acute cessation of peritoneal dialysis, leading to EPS. Recently, EPS has been reported in patients shortly after transplantation suggesting that this procedure may also act as a possible second insult. The process of epithelial-mesenchymal transition of mesothelial cells is proposed to play a central role in the development of peritoneal sclerosis, a common characteristic of patients on dialysis, however, its importance in EPS is less clear. There is no established treatment for EPS although evidence from small case studies suggests that corticosteroids and tamoxifen may be beneficial. Nutritional support is essential and surgical intervention (peritonectomy and enterolysis) is recommended in later stages to relieve bowel obstruction.

Histological and clinical findings in patients with post-transplantation and classical encapsulating peritoneal sclerosis: a European multicenter study

BACKGROUND

Encapsulating peritoneal sclerosis (EPS) commonly presents after peritoneal dialysis has been stopped, either post-transplantation (PT-EPS) or after switching to hemodialysis (classical EPS, cEPS). The aim of the present study was to investigate whether PT-EPS and cEPS differ in morphology and clinical course.

METHODS

In this European multicenter study we included fifty-six EPS patients, retrospectively paired-matched for peritoneal dialysis (PD) duration. Twenty-eight patients developed EPS after renal transplantation, whereas the other twenty-eight patients were classical EPS patients. Demographic data, PD details, and course of disease were documented. Peritoneal biopsies of all patients were investigated using histological criteria.

RESULTS

Eighteen patients from the Netherlands and thirty-eight patients from Germany were included. Time on PD was 78(64-95) in the PT-EPS and 72(50-89) months in the cEPS group (p>0.05). There were no significant differences between the morphological findings of cEPS and PT-EPS. Podoplanin positive cells were a prominent feature in both groups, but with a similar distribution of the podoplanin patterns. Time between cessation of PD to the clinical diagnosis of EPS was significantly shorter in the PT-EPS group as compared to cEPS (4(2-9) months versus 23(7-24) months, p<0.001). Peritonitis rate was significantly higher in cEPS.

CONCLUSIONS

In peritoneal biopsies PT-EPS and cEPS are not distinguishable by histomorphology and immunohistochemistry, which argues against different entities. The critical phase for PT-EPS is during the first year after transplantation and therefore earlier after PD cessation then in cEPS.

Phenotypes of encapsulating peritoneal sclerosis--macroscopic appearance, histologic findings, and outcome

BACKGROUND

Encapsulating peritoneal sclerosis (EPS) is a rare but devastating complication of peritoneal dialysis (PD), with clinical signs of abdominal pain, bowel obstruction, and weight loss in late stages.

METHODS

We retrospectively analyzed all patients who were diagnosed with EPS between March 1998 and October 2011 in our department of nephrology. We focused on the 24 EPS patients who underwent surgery because of symptomatic late-stage EPS. We identified 3 different macroscopic phenotypes of EPS that we categorized as types I - III. We correlated histologic findings with those macroscopic phenotypes of EPS. The postoperative and long-term outcomes were evaluated by macroscopic phenotype.

RESULTS

Duration of PD was longer in type III than in types I and II EPS (p = 0.05). We observed no other statistically significant differences between the groups in baseline characteristics, except for operation time, which was longer in the type I than in the type III group (p = 0.02). Furthermore, we observed no statistically significant difference between the groups with respect to the onset of complaints before surgery (7.8 ± 5.9 months vs 7.0 ± 7.0 months vs 6.5 ± 5.3 months). Concerning patient outcomes, there was no evidence that any of the macroscopic EPS types was associated with more major or minor complications after surgery. For all study patients, follow-up was at least 3 years, with 19 patients still being alive, and 16 having no or very mild complaints. The typical histologic findings of EPS were present in all macroscopic types; only fibrin deposits were more prominent in type II than in type III.

CONCLUSIONS

We describe 3 subtypes of EPS based on macroscopic findings. Postoperative treatment should probably not be influenced by the macroscopic EPS phenotype. Whether the different phenotypes represent different pathophysiologic processes remains unclear and has to be further evaluated.

Effect of sirolimus on the regression of peritoneal sclerosis in an experimental rat model

PURPOSE

Immunosuppressive and anti-inflammatory agents have recently become increasingly popular in the treatment of encapsulating peritoneal sclerosis (EPS). The aim of our study was to investigate the effects of sirolimus on EPS in a rat model.

METHODS

We separated 32 non-uremic rats into four groups: 1 control group, 2 ml isotonic saline injected IP daily for 3 weeks; 2 chlorhexidine gluconate (CG) group, 2 ml 0,1 % CG and 15 % ethanol dissolved in saline injected IP daily for 3 weeks; 3 resting group, CG (weeks 0-3) plus peritoneal rest (weeks 3-6); 4 sirolimus group, CG (weeks 0-3), plus 0.2 ml (1 mg/ml) sirolimus (weeks 3-6). Pathological samples were examined by using hematoxylin eosin (HE) and Masson's trichrome stains. Peritoneal thickness, fibrosis, vascular changes, and inflammation were evaluated by light microscopy. Finally, tissue metalloproteinase (MMP)-2 levels were measured by enzyme-linked immunoassay.

RESULTS

In the CG group, there was a significant increase in peritoneal thickness, inflammatory activity, and fibrosis score compared to the control group (p < 0.05). We also observed a lower fibrosis score and less peritoneal thickening in the sirolimus group compared to the resting and CG groups (p < 0.05). There was no difference in histopathologic findings, except for the inflammatory activity in the sirolimus group, compared to the control group. Although the CG group had higher tissue MMP-2 levels than the control group, the tissue MMP-2 levels were not significantly different from the other groups.

CONCLUSIONS

Sirolimus has a beneficial effect on peritoneal fibrosis induced by CG. This suggests that sirolimus may have therapeutic value in the management of EPS.

Difference in the expression of hormone receptors and fibrotic markers in the human peritoneum--implications for therapeutic targets to prevent encapsulating peritoneal sclerosis

OBJECTIVE

Encapsulating peritoneal sclerosis (EPS) is a rare but life-threatening complication of peritoneal dialysis (PD). The optimal management of patients with EPS is uncertain. In the present study, we investigated differences in the expression of nuclear receptors [progesterone (PR), androgen (AR), vitamin D (VDR), and glucocorticoid (GCR)] in the human peritoneum. We also investigated estrogen receptor (ER), matrix metalloproteinase 9 (MMP9), and transforming growth factor β1 (TGFβ1) in the context of their potential role in tamoxifen therapy.

METHODS

We analyzed clinical and histologic characteristics of 72 peritoneal biopsy specimens (22 from EPS patients, 11 from PD patients, 15 from uremic patients, and 24 from control subjects undergoing hernia repair). For immunophenotyping, we used antibodies against VDR, GCR, ER, PR, AR, MMP9, and TGFβ1.

RESULTS

In human peritoneum, VDR and GCR are highly expressed (98.6% and 87.3% respectively). Except in the case of VDR (p = 0.0012), we observed no significant difference in receptor expression between the groups. Expression of ER and PR was sparse (11.4% and 31% respectively), with higher expression in women, and AR was absent. Minimal MMP9 expression and moderate TGFβ1 expression were observed in all groups. The differences between the groups were nonsignificant.

CONCLUSIONS

Nuclear receptors are present in human peritoneum. Except in the case of VDR, the pattern for any one group is nonspecific. Glucocorticoids, vitamin D, and angiotensin converting-enzyme inhibitors or angiotensin II receptor blockers (via the vitamin D/angiotensin II pathway) might be suitable interventions for preservation of the integrity of the peritoneal membrane. The mechanism of action of tamoxifen is still not elucidated, ER expression in the peritoneum is sparse, and data about the studied pathways (MMP9, TGFβ) are inconsistent.

Update on potential medical treatments for encapsulating peritoneal sclerosis; human and experimental data

Encapsulating peritoneal sclerosis (EPS) is an infrequent but serious complication of peritoneal dialysis (PD). The pathogenesis is unknown but speculation is ongoing. The current management of EPS focuses on prevention and treatment of the inflammatory and fibrotic changes at the level of the peritoneal membrane with immunosuppressive and antifibrotic agents, respectively. This article reviews the currently available human and animal data on potential agents to prevent and/or treat EPS. We propose a strategy for early diagnose EPS in an attempt to avoid the development of the full-blown and potentially life-threatening clinical syndrome of EPS. Future research should focus on studying potential prophylactic and therapeutic agents in humans in large, multicenter, randomized trials but also on early detection of EPS in the inflammatory phase by means of biomarkers and the establishment of a composite EPS score.

The Role of Peritoneal Lavage and the Prognostic Significance of Mesothelial Cell Area in Preventing Encapsulating Peritoneal Sclerosis

♦ Background

Severe peritoneal injury and encapsulating peritoneal sclerosis (EPS) as complications of long-term peritoneal dialysis (PD) are issues of concern. The usefulness of peritoneal lavage after withdrawal of PD and the risk factors for EPS have not been addressed until now. Little is known about mesothelial cell area (MCA) in the effluent as a marker of peritoneal injury. In the present study, we investigated the clinical significance of peritoneal lavage after PD withdrawal and tried to clarify the risk factors related to MCA, with the aim of preventing EPS. We also developed an algorithm for the clinical management of long-term PD patients.

♦ Methods

We assigned 247 PD patients to one of two cohorts after PD withdrawal: a non-lavage group (73 patients) and a lavage group (174 patients). To clarify the risk factors, we studied these potential predictors: PD duration, dialysate-to-plasma ratio of creatinine (D/P Cr) at the time of PD withdrawal, frequency of peritoneal lavage, type of PD or lavage solution, MCA at the time of PD withdrawal (“PD area”), and MCA at the time of peritoneal lavage withdrawal or censoring (“LA area”). Recurrent intestinal obstruction was defined as the main manifestation of EPS. Diagnostic performance and cut-off values were then calculated for the selected risk factors.

♦ Results

The overall incidence of EPS was significantly lower in the lavage group, at 6.9% (5.2% during lavage and 2.5% after lavage), than in the non-lavage group, at 15.1%. The risk factors and cut-off values were PD area (350 μm2) and PD duration (78 months) for the non-lavage group; and PD area (350 μm2) and LA area (320 μm2) for the lavage group. Patients with a PD duration of 78 months or more and a PD area of 350 μm2 or more were defined as high-risk patients in the non-lavage group (risk ratio: 11.14), and patients with a PD area of 350 μm2 or more and an LA area of 320 μm2 or more were defined as high-risk patients in the lavage group (risk ratio: 10.43).

♦ Conclusions

Peritoneal lavage is effective in reducing the incidence of EPS after PD withdrawal. The PD duration and MCA are significant risk factors, and these markers are useful for classifying patients into low- and high-risk groups for the development of EPS.