The relationship between changes in peritoneal membrane solute transfer characteristics and cardiac remodeling in patients with peritoneal dialysis

INTRODUCTION

We aimed to determine the relationship between the dilatation of the heart chambers and the change in peritoneal membrane solute transfer characteristics (PMTC) in long-term peritoneal dialysis (PD) patients.

METHODS

This is a retrospective, single-center study including the follow-up of maintenance PD patients. According to the changes in PMTC from baseline to the last visit, patients were divided into three groups; stable (n = 11), increased (n = 41), and decreased transporters (n = 35).

RESULTS

Left atrium (LA) and Right ventricle (RV) dilatation were more prominent in the PMTC-decreased group compared to PMTC-increased and stable groups (p < 0.001 and p = 0.07, respectively). The Cox regression analysis showed that only decreased PMTC was associated with LA dilatation (HR 2.89 [CI 95%1.54, 5.45] p < 0.01) and RV dilatation (HR 3.01 [CI 95%1.40, 6.21] p < 0.01).

CONCLUSION

PD can be associated with unfavorable dynamic changes in cardiac structure and functions even at the subclinical level.

Acute presentation of cocoon abdomen as intestinal obstruction mimicking with strangulated eventration: A case report

INTRODUCTION

Abdominal cocoon syndrome (ACS), or sclerosing encapsulating peritonitis (SEP) is a rare cause of intestinal obstruction in which the bowel and internal abdominal organs are wrapped with a fibrocollagenous cocoon-like encapsulating membrane. While cocooning of the abdomen primarily manifests in individuals undergoing peritoneal dialysis (PD), it has also been reported to occur spontaneously. Remarkably rare, SEP may present with complete mechanical bowel obstruction in select cases.

CASE PRESENTATION

We hereby report a case of an 87-year-old female patient with a prior history of abdominal surgery, who presented to our emergency department with a clinical picture of complete small bowel obstruction. Clinical and radiological data were suggestive of a strangulated midline hernia, prompting a therapeutic laparotomy. The surgical exploration revealed the encasement of the small bowel loops within a thick fibrocollagenous membrane. Efficient resolution was achieved through skillful adhesiolysis and the meticulous excision of the fibrocollagenous membrane.

DISCUSSION

SEP is more prevalent in men, with a higher incidence observed in tropical and subtropical countries. While the precise pathophysiology remains elusive, it is hypothesized that subclinical intraabdominal inflammation gives rise to the formation of a dense fibrocollagenous membrane. This membrane encapsulates intraperitoneal organs, ultimately leading to intestinal obstruction. Patients typically present with a recurrent history of small bowel obstruction, notably in the absence of prior abdominal surgery. Abdominal CT scan with experienced radiologist interpretation can aid in preoperative diagnosis. In cases where non-operative management fails and recurrent obstructions persist, surgical adhesiolysis stands as the well-established gold standard.

CONCLUSION

SEP is a rare abdominal disease, posing challenges for preoperative diagnosis. Laparotomy plays an important role in its diagnosis and treatment. The primary objective of the surgical intervention is to release the encapsulation of the bowel and safeguard the optimal functioning of the small intestines as much as possible.

Laparoscopic Surgery for Sigmoid Colon Cancer in a Patient With a History of Two Renal Transplantations and Peritoneal Dialysis

The development of transplantation technology has improved the prognosis of transplantation surgery; however, the negative impact of immunosuppressive drugs has increased the number of patients with cancer after transplantation. Recently, minimally invasive surgery has become more common for cancer treatment. We report our experience of performing laparoscopic sigmoid colon resection for a patient with a history of two renal transplantations and peritoneal dialysis. A 42-year-old male patient who developed purpura nephropathy underwent renal transplantation at ages eight and 34 years. He had been on peritoneal dialysis for five years before the second transplantation. The patient was referred to our department with the chief complaint of sudden abdominal pain. After an examination of imaging, we obtained a diagnosis of sigmoid colon cancer. Despite a history of peritoneal dialysis, laparoscopic sigmoid colon resection was successfully performed without complications after confirming that there were no adhesions in the abdominal cavity. The left lower port position had to be adjusted because the transplanted kidney protruded into the left iliac fossa. No postoperative complications and graft loss occurred. In this case, laparoscopic surgery was effective in lowering the risk of damage to the transplanted kidney and safely performing the procedure. The number of colorectal cancer cases in renal transplant patients is expected to increase, and some of these patients will have a history of peritoneal dialysis, which may make surgery more difficult. The successful outcome of this case highlights that laparoscopic surgery could be viable for patients with such a complex medical history.

Encapsulating Peritoneal Sclerosis 43 Years after Distal Gastrectomy for Early Gastric Cancer

We herein report a case of encapsulating peritoneal sclerosis (EPS) in a patient without chronic kidney disease after gastrectomy. A 69-year-old man underwent distal gastrectomy for early gastric cancer at 25 years old. After 43 years, he developed bowel obstruction and underwent enterolysis of the encapsulated small intestine. A pathological examination of the capsular membranes revealed inflammation, foam, and giant cells that destroyed foreign substances. The patient was discharged 1.5 months later. Foreign body reactions to surgical instruments used in gastrectomy are considered a cause of EPS. EPS due to foreign body reactions to surgical instruments should also be considered in such cases.

C allele in transforming growth factor-β1 rs1800471 gene polymorphisms might indicate a protective feature in encapsulating peritoneal sclerosis development

INTRODUCTION

Peritoneal fibrosis may progress in peritoneal dialysis (PD) patients to a fatal clinical condition called encapsulating peritoneal sclerosis (EPS). Transforming growth factor (TGF)-β plays a pivotal role in the pathogenesis of peritoneal fibrosis. We aimed to investigate the association among polymorphisms in the gene encoding TGF-β1, which were -509C/T (rs1800469), +869T/C (rs1982073), and +915G/C (rs1800471) in EPS patients.

METHODS

A total of 16 PD patients who were clinically and radiologically diagnosed with EPS were enrolled and 22 age- and gender-matched PD patients were selected as the non-EPS group.

RESULTS

G allele frequency at the rs1800471 gene polymorphism was significantly higher in the EPS group than non-EPS group (p = 0.005). Interestingly, the non-EPS group patients had CC or CG polymorphisms.

CONCLUSION

C allele in TGF-β1 rs1800471 gene polymorphisms might indicate a protective feature in EPS development. Knowing the presence of polymorphism may be effective in selecting renal replacement therapy in patients.

Encapsulating peritoneal sclerosis post liver transplant and peritoneal dialysis: case report and literature review

Encapsulating peritoneal sclerosis (EPS) is a rare and debilitating condition. A fibrocollagenous membrane, which promotes encasement of the small intestine leaving a cocoon-like appearance, takes place. It is mainly associated with peritoneal infections, medications, peritoneal dialysis and systemic inflammatory diseases. Diagnosis is based on clinical history, intestinal obstruction and imaging exam. We report a case of EPS in a 68-year-old man with a medical history of liver transplantation and peritoneal dialysis, complaining of obstructive bowel symptoms.

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.

Risk factors for Encapsulating Peritoneal Sclerosis in patients undergoing peritoneal dialysis: A meta-analysis

Purpose

Encapsulating Peritoneal Sclerosis (EPS) is the most serious complication of long-term peritoneal dialysis (PD), which considerably reduces the patient’s quality of life, leading to patients discontinuing PD. Considering these negative effects, it is necessary to systematically review and determine the risk factors of EPS.

Methods

The PubMed, Embase, Web of Science, Cochrane Library, and China Biology Medicine (CBM) were searched from their inception to January 1st, 2022, and the bibliographies from the citations of relevant articles were manually searched. The ROBINS-I (Risk of Bias in Non-randomized studies of Interventions) tool was used to evaluate the risk of bias of included studies.

Results

Ten studies involving 12595 participants were included in this meta-analysis. The results revealed that a younger age at PD onset (MD = -7.70, 95% CI, -11.53~-3.86), a higher transporter (MD = 0.13, 95% CI, 0.09~0.18), a longer PD duration (SMD = 1.15, 95% CI, 0.68~1.61), a longer peritonitis duration (MD = 12.66, 95% CI, 3.85~21.47), and history of glomerulonephritis (OR = 1.42, 95% CI, 1.02~1.97) were significant risk factors for EPS. However, sex, use of icodextrin, the number of peritonitis episodes, and history of multicystic kidney disease did not affect the risk of EPS.

Conclusions

This review provides a scientific basis for further understanding the etiology of PD-related EPS and improving prevention strategies. More high-quality studies are necessary to validate this paper’s findings.

The Peritoneal Membrane—A Potential Mediator of Fibrosis and Inflammation among Heart Failure Patients on Peritoneal Dialysis

Peritoneal dialysis is a feasible, cost-effective, home-based treatment of renal replacement therapy, based on the dialytic properties of the peritoneal membrane. As compared with hemodialysis, peritoneal dialysis is cheaper, survival rate is similar, residual kidney function is better preserved, fluid and solutes are removed more gradually and continuously leading to minimal impact on hemodynamics, and risks related to a vascular access are avoided. Those features of peritoneal dialysis are useful to treat refractory congestive heart failure patients with fluid overload. It was shown that in such patients, peritoneal dialysis improves functional status and quality of life, reduces hospitalization rate, and may decrease mortality rate. High levels of serum proinflammatory cytokines and fibrosis markers, among other factors, play an important part in congestive heart failure pathogenesis and progression. We demonstrated that those levels decreased following peritoneal dialysis treatment in refractory congestive heart failure patients. The exact mechanism of beneficial effect of peritoneal dialysis in refractory congestive heart failure is currently unknown. Maintenance of fluid balance, leading to resetting of neurohumoral activation towards a more physiological condition, reduced remodeling due to the decrease in mechanical pressure on the heart, decreased inflammatory cytokine levels and oxidative stress, and a potential impact on uremic toxins could play a role in this regard. In this paper, we describe the unique characteristics of the peritoneal membrane, principals of peritoneal dialysis and its role in heart failure patients.

Surgical management of Encapsulating Peritoneal Sclerosis (EPS) in children: international case series and literature review

BACKGROUND

Encapsulating Peritoneal Sclerosis (EPS) is a rare phenomenon in paediatric patients with kidney failure treated with peritoneal dialysis (PD). This study highlights clinical challenges in the management of EPS, with particular emphasis on peri-operative considerations and surgical technique.

METHODS

Retrospective analysis of all paediatric patients with EPS treated at the Manchester Centre for Transplantation.

RESULTS

Four patients were included with a median duration of 78 months on PD. All patients had recurrent peritonitis (> 3 episodes), and all had symptoms within three months of a change of dialysis modality from PD to haemodialysis or transplant. In Manchester, care was delivered by a multi-disciplinary team, including surgeons delivering the adult EPS surgical service with a particular focus on nutritional optimisation, sepsis control, and wound management. The surgery involved laparotomy, lavage, and enterolysis of the small bowel + / - stoma formation, depending on intra-abdominal contamination. Two patients had a formal stoma, which were reversed at three and six months, respectively. Two patients underwent primary closure of the abdomen, whereas two patients had re-look procedures at 48 h with secondary closure. One patient had a post-operative wound infection, which was managed medically. One patient's stoma became detached, leading to an intra-abdominal collection requiring re-laparotomy. The median length of stay was 25 days, and patients were discharged once enteral feeding was established. All patients remained free of recurrence with normal gut function and currently two out of four have functioning transplants.

CONCLUSIONS

This series demonstrates 100% survival and parenteral feed independence following EPS surgery. Post-operative morbidity was common; however, with individualised experience-based decision-making and relevant additional interventions, patients made full recoveries. Health and development post-surgery continued, allowing the potential for transplantation. A higher resolution version of the Graphical abstract is available as Supplementary information.

Recent Understanding of Peritoneal Pathology in Peritoneal Dialysis Patients in Japan

The thin peritoneum covering the peritoneal cavity has been used as a dialysis membrane for peritoneal dialysis (PD) because it is highly vascularized and has a large body surface area. However, it has been reported that peritoneal membranes affected by peritonitis, as well as those exposed to the nonphysiological high glucose levels containing PD dialysate, may undergo histological and functional changes. Patients undergoing PD may experience encapsulating peritoneal sclerosis (EPS), which is a life-threatening serious complication of PD that can significantly impair activities of daily living. The incidence of EPS was 1.4-7.3% of maintenance PD patients in the 1980s. The incidence has improved to 1.0% after a neutral dialysate became the standard PD treatment in Japan. Furthermore, the pathogenesis of EPS is uncertain although its onset may be explained by the "two-hit theory," in which some factors leading to impairment had an additive effect on simple peritoneal sclerosis. The evaluation of histopathological findings has shown the impact of the neutral dialysate on peritoneal deterioration as well as its role in the development of functional changes. In the present report, we discuss the advances in the understanding of peritoneal deterioration based on histological and macroscopic evaluations of the peritoneum of patients undergoing PD. We also discuss the recent treatment for PD patients.

[Standardized histomorphological processing of peritoneal biopsies as part of the German Peritoneal Biopsy Registry (GRIP, German registry in PD)]

The peritoneal lining of the abdominal cavity consists of a parietal and visceral sheet. The serosa is an interesting organ, which in medical practice is particularly important in the context of chronic peritoneal dialysis (PD). This method of renal replacement therapy utilizes the semipermeability of the peritoneal surface by applying PD solutions of differing osmolarity to eliminate toxic substances and regulate fluid and electrolyte equilibrium. This method is an ideal approach especially for younger patients and is very effective at least for some time. Pre-existing injury to the peritoneum, for example as a consequence of chronic renal insufficiency or associated comorbidities and inflammatory changes that develop during PD, results in a structural remodelling of the serosa. As a consequence, the filtering function of the serosa is lost and PD has to be replaced by another renal replacement therapy. Thorough knowledge of the morphology of peritoneal changes as well as of the risk factors is of paramount importance for therapeutic management and prognosis of PD patients. In order to take this into account, the German Registry In Peritoneal Dialysis (Deutsches Peritonealbiopsieregister, GRIP) was founded a few years ago, which now includes roughly 1700 biopsies, of which detailed clinical and histomorphological information was systematically acquired and collected.

Vasculopathy plays an important role during the development and relapse of encapsulating peritoneal sclerosis with conventional peritoneal dialysis solutions

Background

Encapsulating peritoneal sclerosis (EPS) is an uncommon but life-threatening complication of peritoneal dialysis (PD) therapy. The causative factors of EPS remain unclear. Pathological studies of the peritoneum affected by EPS and relationships with clinical factors including PD solutions remain lacking. The objective of this study was to examine peritoneal samples from EPS patients and to identify the associations of peritoneal pathology with different clinical factors.

Methods

Peritoneal specimens were obtained at the time of surgical enterolysis in Tsuchiya General Hospital from 1993 to 2016. A total of 223 PD patients were enrolled and analyzed. Tissues were fixed with formalin and processed with hematoxylin and eosin and Masson’s trichrome staining, as well as immunohistochemical staining for CD31 and CD68.

Results

Evaluations could be made in 174 patients who received surgical enterolysis. Conventional or pH-neutral low-glucose degradation product PD solutions were utilized during PD treatment. The conventional PD solution group showed less angiogenesis (P = 0.013) but more severe vasculopathy, in the form of a lower ratio of luminal diameter to vessel diameter (L/V ratio) (P &lt; 0.001) in association with longer PD treatment. Multivariate Cox proportional hazard models revealed that L/V ratio (per 0.1 increase, hazard ratio = 0.88, 95% confidence interval 0.77–0.99, P = 0.047) was significantly associated with a lower incidence of EPS relapse. In contrast, most of the cases in the pH-neutral solution group showed milder vasculopathy.

Conclusions

The pathology of EPS differed between conventional and pH-neutral solution groups. Vasculopathy was related to the development and relapse of EPS in the conventional solution group.

Technological Advances in Peritoneal Dialysis Research Peritoneal Cell Culture: Fibroblasts

Fibroblasts have been traditionally viewed as providing little more than a structural lattice for other cell types. However, recent data indicate that fibroblasts play a key and early role in many pathophysiological processes, including inflammation, fibrosis, and neoplasia. Moreover, depending on the anatomical location, fibroblasts display significant functional heterogeneity. Therefore, it is important to study the subpopulation of fibroblasts derived exactly from the organ of interest rather than to extrapolate the observations made in other fibroblast subsets. Cell culture provides a powerful tool for studying the role of fibroblasts in various contexts. In this review, we describe procedures for establishing and identifying primary cultures of human peritoneal fibroblasts. We also briefly discuss the potential involvement of peritoneal fibroblasts in peritoneal pathology.

Long-term outcomes in patients with encapsulating peritoneal sclerosis managed with nutritional support

BACKGROUND

Little is known about long-term survivors with encapsulating peritoneal sclerosis (EPS). Published literature focuses on patients managed surgically. We describe our experience of the long-term outcomes in patients with EPS conservatively managed with nutritional support alone.

METHODS

This is a single-centre retrospective observational study of patients who had survived for ≥5 years since diagnosis. EPS survivors were invited for review of symptoms, nutritional assessment and evaluation of quality of life. Radiological progression was assessed based on serial computed tomography (CT) scores for each patient.

RESULTS

A total of 23 patients with a diagnosis of EPS for at least 5 years were identified, with 18 patients alive at the time of the study. Of these 18 patients, 10 patients transferred to haemodialysis (HD) and 8 patients received kidney transplants. Commonest symptoms were nausea (91%) and vomiting (73%). Mean body mass index for patients was within the ideal and healthy range, with only 11% suffering from continued weight loss. In all, 70% EPS survivors on HD received nutritional support compared to 15% of those with transplants; 17% required ongoing parenteral nutrition. Of the 11 patients with serial CT scans at least 4 years apart, 10 had an increase in radiological score for EPS but with no apparent correlation to clinical outcomes. There were no significant differences in the reported quality of life between EPS survivors on HD and those transplanted, with self-rated health status equivalent to that reported for the general end-stage kidney disease (ESKD) population.

CONCLUSION

Long-term survival following EPS managed conservatively with nutritional support is feasible, with the majority no longer requiring nutritional support and having a quality of life similar to other patients with ESKD.

Outcomes of the surgical management of encapsulating peritoneal sclerosis: A case series from a single center in Korea

Background

Encapsulating peritoneal sclerosis (EPS) is a rare but near-fatal complication of peritoneal dialysis (PD). Despite the high mortality rate of EPS, the surgical treatment strategy of severe EPS is yet to be established.

Methods

We retrospectively analyzed outcomes of patients with EPS who underwent enterolysis for intractable EPS at Seoul National University Hospital between 2001 and 2018. EPS was diagnosed based on the clinical symptoms and radiological findings of abdominal computed tomography (CT). CT scans were scored according to an EPS scoring system that assessed peritoneal thickening and calcification as well as bowel thickening, tethering, loculation, and dilatation.

Results

Thirteen patients (nine males and four females; age, 48 [29–63] years) underwent enterolysis for severe EPS. PD duration (11 [6–21] years) was not associated with survival. Two patients were newly diagnosed with EPS following kidney transplantation. Five patients died of infectious complications immediately after the surgery. Eight patients survived after the first surgery; however, five of them underwent reoperation but died of persistent infection, fistula formation, or adhesive bowel obstruction. Four young (< 60 years) male patients with relatively low CT scan scores (< 13) survived for > 2 years after the first surgery. Median survival duration from EPS diagnosis was 22 (1.3–184) months and that from the first surgery was 9 (0.3–153) months.

Conclusion

The high mortality rate of EPS suggests the importance of appropriate surgical intervention in young symptomatic male EPS patients with relatively low CT scan scores.

Clinical risk factors and outcomes of massive ascites accumulation after discontinuation of peritoneal dialysis

Background

Encapsulating peritoneal sclerosis (EPS) is a serious complication of peritoneal dialysis (PD), with high morbidity and mortality that requires an early diagnosis for effective treatment. PD withdrawal and bacterial peritonitis are important triggers for the onset of EPS. However, few studies have focused on cases of PD withdrawal without a clinical diagnosis of peritonitis, cirrhosis, or carcinomatosis. We aimed to compare the clinical characteristics and computed tomography (CT) images of patients with or without ascites in such situations and assess clinical outcomes in terms of mortality.

Methods

Our retrospective review included 78 patients who withdraw PD between January 2000 and December 2017.

Results

Ten patients had ascites, and 68 did not have a significant intra-abdominal collection. The ascites group had a significantly longer PD duration (months; 134.41 [range, 35.43–181.80] vs. 32.42 [733–183.47], p < 0.001) and higher peritoneal membrane transport status based on the dialysate-to-plasma ratios of creatinine (0.78 ± 0.08 vs. 0.68 ± 0.11, p = 0.009) and glucose (0.27 ± 0.07 vs. 0.636 ± 0.08, p = 0.001) than the control group. CT parameters, including peritoneal calcification, thickness, bowel tethering, or bowel dilatation, were not all present in each patient with ascites and EPS. During the 12-month study period, the ascites group had a higher risk for developing EPS (70% vs. 0%, p < 0.001) and a higher 12-month all-cause mortality (30% vs. 0%, p = 0.002).

Conclusions

Ascites accumulation was not rare after PD discontinuation. A longer PD duration and high peritoneal membrane transport status could predict subsequent ascites accumulation. Furthermore, patients with ascites were at a higher risk of EPS.

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.

Crucial Role of NLRP3 Inflammasome in the Development of Peritoneal Dialysis-related Peritoneal Fibrosis

Long-term peritoneal dialysis (PD) therapy leads to peritoneal inflammation and fibrosis. However, the mechanism underlying PD-related peritoneal inflammation and fibrosis remains unclear. NLRP3 inflammasome regulates the caspase-1-dependent release of interleukin-1β and mediates inflammation in various diseases. Here, we investigated the role of NLRP3 inflammasome in a murine model of PD-related peritoneal fibrosis induced by methylglyoxal (MGO). Inflammasome-related proteins were upregulated in the peritoneum of MGO-treated mice. MGO induced parietal and visceral peritoneal fibrosis in wild-type mice, which was significantly reduced in mice deficient in NLRP3, ASC, and interleukin-1β (IL-1β). ASC deficiency reduced the expression of inflammatory cytokines and fibrotic factors, and the infiltration of macrophages. However, myeloid cell-specific ASC deficiency failed to inhibit MGO-induced peritoneal fibrosis. MGO caused hemorrhagic ascites, fibrin deposition, and plasminogen activator inhibitor-1 upregulation, but all of these manifestations were inhibited by ASC deficiency. Furthermore, in vitro experiments showed that MGO induced cell death via the generation of reactive oxygen species in vascular endothelial cells, which was inhibited by ASC deficiency. Our results showed that endothelial NLRP3 inflammasome contributes to PD-related peritoneal inflammation and fibrosis, and provide new insights into the mechanisms underlying the pathogenesis of this disorder.

CXCR4-Receptor-Targeted Liposomes for the Treatment of Peritoneal Fibrosis

Peritoneal fibrosis (PF) is a common complication of long-term peritoneal dialysis (PD). It is considered as the main reason for dialysis inadequacy and PD withdrawal. Transforming growth factor beta (TGF-β) regulates the expression of stromal cell-derived factor 1 (SDF-1α) and its receptor C-X-C chemokine receptor type 4 (CXCR4) on human peritoneal mesothelial cells (HPMCs), resulting in an increased migratory potential of HPMCs and extracellular matrix (ECM) deposition in the scar tissue and eventually fibrosis. Because SDF-1α/CXCR4 activation has a vital role in the pathogenesis of PF, codelivery of a CXCR4-receptor targeting agent with an antifibrotic agent in a single nanocarrier can be a promising strategy for treating PF. Here, for the first time, AMD3100 (AMD), a CXCR4-receptor antagonist, was coformulated with sulfotanshinone IIA sodium (STS IIA) into a liposome (STS-AMD-Lips) to develop a CXCR4 receptor targeting form of combination therapy for PF. CXCR4 targeting increased the ability of liposomes to target fibrotic peritoneal mesothelial cells overexpressing CXCR4 and facilitated the ability of STS IIA treatment at the fibrotic site. The liposome had an average diameter of 103 nm with encapsulated efficiencies of above 50%. The in vivo studies confirmed the reversal of PD solution-induced epithelial-to-mesenchymal transition by STS-AMD-Lips in HPMCs. The in vivo studies also revealed the precise biodistribution of the liposomes to peritoneum. Significant reduction of the morphological lesions and decreased level of ECM proteins were observed in rats treated with STS-AMD-Lips, proving that the liposomal nanocarrier has excellent ability to reverse PF. It has been concluded that the STS-AMD-Lips exhibit specific peritoneal targeting ability and could be used to improve STS-AMD combination delivery for the treatment of PF.

Sclerosing encapsulating peritonitis: imaging findings in an uncommon entity

OBJECTIVES

To describe the most characteristic imaging findings for sclerosing encapsulating peritonitis, with an emphasis on the computed tomography findings.

CONCLUSION

The incidence of sclerosing encapsulating peritonitis is low. The pathophysiology of this condition is unclear. Two types are recognized: idiopathic and secondary; the secondary type is generally a complication of peritoneal dialysis. Its nonspecific clinical presentation and the absence of blood markers mean that sclerosing encapsulating peritonitis is usually diagnosed late. Thus, it is important to know the imaging signs; these include thickening and calcification of the peritoneum and dilation of bowel loops with thickening and calcification of bowel walls, whether in isolation or in association with loculated ascites. Although ultrasonography allows the complexity of the collections to be evaluated, computed tomography is the most useful technique for the general assessment of the signs mentioned above.

Simultaneous Removal And Reinsertion of the PD Catheter in Relapsing Peritonitis

Background:Relapsing peritonitis in peritoneal dialysis (PD) is associated with lower cure rates and more hemodialysis (HD) transfers, as catheter removal is recommended in these situations. The aim of our study was to evaluate the continuation of PD without perioperative transfer to HD in patients who underwent a simultaneous catheter removal and replacement for relapsing peritonitis.Methods:This was a retrospective monocentric study. Patients with simultaneous catheter removal and replacement for relapsing peritonitis or peritonitis at high risk of relapse (fungal or Pseudomonas infection) between 1 January 2007 and 31 December 2016 were included. The events of interest were the continuation of PD without perioperative transfer to HD, postoperative complications, new infection with the same organism, and technique survival.Results:Of the 271 incident patients in PD during this period, 11 had a simultaneous catheter removal and replacement for relapsing peritonitis (8) or high risk of relapse peritonitis (3). Eight (72.7%) patients pursued PD without transfer to HD. Six infections were due to microorganisms other than gram-positive cocci. At 1 year, 7 (63.6%) of the 11 patients were still on PD. After the surgery, there were no peritonitis or catheter-related infections caused by the same organism.Conclusion:Simultaneous catheter removal and replacement for peritonitis appears to be an effective procedure for maintaining patients on PD.

Anti-C5a complementary peptide mitigates zymosan-induced severe peritonitis with fibrotic encapsulation in rats pretreated with methylglyoxal

In a previous study of fungal peritoneal injury in peritoneal dialysis patients, complement (C)-dependent pathological changes were developed in zymosan (Zy)-induced peritonitis by peritoneal scraping. However, the injuries were limited to the parietal peritoneum and did not show any fibrous encapsulation of the visceral peritoneum, which differs from human encapsular peritoneal sclerosis (EPS). We investigated peritoneal injury in a rat model of Zy-induced peritonitis pretreated with methylglyoxal (MGO) instead of scraping (Zy/MGO peritonitis) to clarify the role of C in the process of fibrous encapsulation of the visceral peritoneum. Therapeutic effects of an anti-C5a complementary peptide, AcPepA, on peritonitis were also studied. In Zy/MGO peritonitis, peritoneal thickness, fibrin exudation, accumulation of inflammatory cells, and deposition of C3b and C5b-9 with loss of membrane C regulators were increased along the peritoneum until day 5. On day 14, fibrous encapsulation of the visceral peritoneum was observed, resembling human EPS. Peritoneal injuries and fibrous changes were significantly improved with AcPepA treatment, even when AcPepA was administered following injection of Zy in Zy/MGO peritonitis. The data show that C5a might play a role in the development of encapsulation-like changes in the visceral peritoneum in Zy/MGO peritonitis. AcPepA might have therapeutic effects in fungal infection-induced peritoneal injury by preventing subsequent development of peritoneal encapsulation.

Risk factors for encapsulating peritoneal sclerosis: Analysis of a 36-year experience in a University Hospital

AIM

Encapsulating peritoneal sclerosis (EPS) is a rare but serious complication that occurs in peritoneal dialysis (PD) therapy. The present study aimed to identify the risk factors, especially peritonitis and biocompatible PD fluid.

METHODS

The study included 703 patients who received PD between January 1980 and March 2015 at two centres. The patients were divided into two groups: those who had developed EPS (EPS group: n = 44) and those who had no documentary evidence of EPS (non-EPS group: n = 659). The independent risks of EPS were determined by univariate and multivariate logistic models.

RESULTS

Encapsulating peritoneal sclerosis occurred in 44/703 (6.3%) patients between January 1980 and March 2015. In multivariate logistic models of risk factors correlated with EPS, dialysate to plasma creatinine ratio (D/P Cr) by peritoneal equilibration test (PET) and history of peritonitis were risk factors for EPS development (P < 0.01, respectively) in addition to PD duration. Especially, total duration of peritonitis, defined by period between onset and resolution of peritonitis, was an important risk factor for EPS development in patients with a history of peritonitis. Receiver operating characteristic (ROC) curve analysis revealed that cut-off point for EPS development was 36 days. Moreover, biocompatible PD fluid contributed to decreased EPS development.

CONCLUSION

Both the longer duration of peritonitis and higher D/P Cr, as well as the longer PD duration, were risk factors for EPS development. Furthermore, use of biocompatible PD fluid contributed to the decrease in EPS development.

Encapsulating Peritoneal Sclerosis

Encapsulating peritoneal sclerosis (EPS) is a rare but serious complication of peritoneal dialysis. In this review, we describe the clinical picture and histologic changes to the peritoneal membrane that are associated with EPS and provide an update on current diagnosis and management. We also discuss the recent studies that have suggested that the use of more biocompatible solutions containing lower concentrations of glucose degradation product that often are pH neutral in combination with a change in clinical practice (reducing glucose exposure and monitoring peritoneal membrane function) might ameliorate peritoneal degeneration, reduce the incidence of EPS, and minimize the severity of the disease.

A prospective, proteomics study identified potential biomarkers of encapsulating peritoneal sclerosis in peritoneal effluent

Encapsulating peritoneal sclerosis (EPS) is a potentially devastating complication of peritoneal dialysis (PD). Diagnosis is often delayed due to the lack of effective and accurate diagnostic tools. We therefore examined peritoneal effluent for potential biomarkers that could predict or confirm the diagnosis of EPS and would be valuable in stratifying at-risk patients and driving appropriate interventions. Using prospectively collected samples from the Global Fluid Study and a cohort of Greek PD patients, we utilized 2D SDSPAGE/ MS and iTRAQ to identify changes in the peritoneal effluent proteome from patients diagnosed with EPS and controls matched for treatment exposure. We employed a combinatorial peptide ligand library to compress the dynamic range of protein concentrations to aid identification of low-abundance proteins. In patients with stable membrane function, fibrinogen γ-chain and heparan sulphate proteoglycan core protein progressively increased over time on PD. In patients who developed EPS, collagen-α1(I), γ-actin and Complement factors B and I were elevated up to five years prior to diagnosis. Orosomucoid-1 and a2-HS-glycoprotein chain-B were elevated about one year before diagnosis, while apolipoprotein A-IV and α1-antitrypsin were decreased compared to controls. Dynamic range compression resulted in an increased number of proteins detected with improved resolution of protein spots, compared to the full fluid proteome. Intelectin-1, dermatopontin, gelsolin, and retinol binding protein-4 were elevated in proteome-mined samples from patients with EPS compared to patients that had just commenced peritoneal dialysis. Thus, prospective analysis of peritoneal effluent uncovered proteins indicative of inflammatory and pro-fibrotic injury worthy of further evaluation as diagnostic/prognostic markers.

Encapsulating peritoneal sclerosis in liver transplant recipients: a report of 2 cases

Encapsulating peritoneal sclerosis (EPS) is a rare cause of intestinal obstruction by a thick fibrous membrane wrapping around the small intestine. It is a possible complication after liver transplantation (LT) that can be fatal. This report describes 2 cases of EPS after LT that were successfully treated with surgery, corticosteroids, tamoxifen, and mammalian target of rapamycin inhibitor. After treatment in both cases, the patients were able to start oral feeding and have been symptom free for more than 1 year. These cases suggests that for the management of EPS, surgical treatment is mandatory when the patients present with symptoms of intestinal obstruction or if there are findings suggestive of decreased mural perfusion. Surgery should be accompanied with medical treatment to prevent the relapse of EPS.

Evaluation for Peritoneal Injury at an Early Stage Using Dual Macromolecular Markers

Long-term peritoneal dialysis (PD) frequently produces morphological and functional changes of the peritoneum, making continuation of PD difficult. Therefore, it is necessary to evaluate peritoneal injury at an early stage and develop appropriate therapies. The aims of the present study were to evaluate peritoneal injury at an early stage and assess a drug for prevention of peritoneal injury using our previously developed novel evaluation method. Peritoneal injury was induced in model animals by intraperitoneal injection of methylglyoxal (MGO) for 1 to 5 consecutive days or chlorhexidine digluconate (CG) for 1 to 14 consecutive days. Tetramethylrhodamine-dextran (RD)-10 and fluorescein isothiocyanate-dextran (FD)-2000 were then injected into the peritoneal cavity and recovered after 120 min to evaluate peritoneal injury. The ratio of the concentration of RD-10 to FD-2000 (RD-10/FD-2000 ratio) significantly decreased in animals that had been treated with MGO or CG for 1 d. Moreover, the RD-10/FD-2000 ratio significantly increased in CG- and thalidomide-treated animals. The RD-10/FD-2000 ratio can be used to evaluate peritoneal injury at an early stage and assess the drug efficacy of thalidomide for prevention of peritoneal injury. This study will contribute to the development of therapeutic treatments for peritoneal injury.

Pancreatic lipase activity in overnight effluent predicts high transport status in peritoneal dialysis patients

BACKGROUND

Long-term peritoneal dialysis (PD) causes peritoneal morphological and functional changes, resulting in high transport status featuring increased peritoneal permeability. High transport status is diagnosed by peritoneal equilibration test (PET), a reliable but time-consuming method. We identifed a reliable biomarker in peritoneal effluent to predict high transport status in PD patients.

METHODS

We collected peritoneal effluent and serum from 33 PD patients and measured common laboratory test parameters. High transport status was determined by PET if the dialysate/plasma ratio of creatinine at 4h dwell (D/P Cr 4h) was ≥0.81.

RESULTS

There were significant correlations between D/P Cr 4h and some laboratory parameters in overnight effluent (pancreatic lipase activity, r=0.65, p<0.001; β₂-microglobulin concentration, r=0.59, p<0.001; IL-6 concentration, r=0.53, p<0.001; and CA125 concentration, r=0.29, p=0.027). In a multivariate logistic regression analysis, the pancreatic lipase activity in overnight effluent was identified as an independent predictor of high transport status even after adjusting for age, PD duration, and glomerular filtration rate [OR=1.43 (95% CI: 1.11-1.83), p=0.005].

CONCLUSIONS

The pancreatic lipase activity in overnight effluent is an independent predictor of high transport status in PD patients.

A combination of corticosteroid, sirolimus, and intradialytic parenteral nutrition in encapsulating peritoneal sclerosis: Case report and literature review

Encapsulating peritoneal sclerosis (EPS) is a rare complication of peritoneal dialysis that carries a high morbidity and mortality. Although its pathogenesis is still not clear, the "two hit theory" suggests that long term deterioration of the peritoneum combined with intraperitoneal inflammation is needed in the pathogenesis of EPS. To date, there is no proven effective therapy with an absence of randomized controlled trials. Individual case reports and small case series have reported on the use of tamoxifen and corticosteroids for medical management of EPS. Here, we present the first case of EPS treated successfully with a combination of sirolimus, low dose corticosteroid and intradialytic parenteral nutrition. A critical review of the relevant literature on this subject is also presented to determine the best approach.

Identification of Gene Transcripts Implicated in Peritoneal Membrane Alterations

♦ BACKGROUND: Permanent stimulation of the peritoneum during peritoneal dialysis (PD) is likely to result in increased expression of genes encoding proteins involved in inflammation and tissue remodeling. Peritoneal fibrosis and neoangiogenesis may develop. ♦ OBJECTIVE: To assess highly expressed genes potentially in volved in peritoneal alterations during PD treatment using an animal model. ♦ METHODS: A PD catheter was implanted in 36 male Wistar rats after 70% nephrectomy. The rats were divided into 3 groups, exposed to dialysis solution for 8 weeks, and sacrificed 2 weeks later. Group B was exposed to a buffer, group D was exposed to a 3.86% glucose-based dialysis solution, and in group D+H, a second hit of intraperitoneal blood on top of the dialysis solution was given to induce the development of peritoneal sclerosis. Before sacrifice, peritoneal function was assessed. Omental tissue was obtained for analysis of gene expression using RT-qPCR. ♦ RESULTS: Fibrosis scores, vessel counts, and peritoneal function parameters were not different between the groups. Genes involved in the transforming growth factor beta signaling pathway, cell proliferation, angiogenesis, and inflammation were more expressed (p < 0.05) in the D+H group. Almost no differences were found between the control groups. We identified 4 genes that were related to peritoneal transport. ♦ CONCLUSION: Already a mid-term peritoneal exposure, when no microscopical and functional alterations are present, provokes activation of gene pathways of cell proliferation, fibrosis, neoangiogenesis, and inflammation.

Vascular Endothelial Cell Injury Is an Important Factor in the Development of Encapsulating Peritoneal Sclerosis in Long-Term Peritoneal Dialysis Patients

Background and Objectives

Encapsulating peritoneal sclerosis (EPS) is a rare but serious and life-threatening complication of peritoneal dialysis (PD). However, the precise pathogenesis remains unclear; in addition, predictors and early diagnostic biomarkers for EPS have not yet to be established.

Methods

Eighty-three peritoneal membrane samples taken at catheter removal were examined to identify pathological characteristics of chronic peritoneal deterioration, which promotes EPS in patients undergoing long-term PD treatment with low occurrence of peritonitis.

Results

According to univariable logistic regression analysis of the pathological findings, thickness of the peritoneal membrane (P = 0.045), new membrane formation score (P = 0.006), ratio of luminal diameter to vessel diameter (L/V ratio, P<0.001), presence of CD31-negative vessels (P = 0.021), fibrin deposition (P<0.001), and collagen volume fraction (P = 0.018) were associated with EPS development. In analyses of samples with and without EPS matched for PD treatment period, non-diabetes, and PD solution, univariable analysis identified L/V ratio (per 0.1 increase: odds ratio (OR) 0.44, P = 0.003) and fibrin deposition (OR 6.35, P = 0.027) as the factors associated with EPS. L/V ratio was lower in patients with fibrin exudation than in patients without fibrin exudation.

Conclusions

These findings suggest that damage to vascular endothelial cells, as represented by low L/V ratio, could be a predictive finding for the development of EPS, particularly in long-term PD patients unaffected by peritonitis.

Unusual intestinal obstruction due to idiopathic sclerosing encapsulating peritonitis: a report of two cases and a review

Sclerosing encapsulating peritonitis (SEP) is a rare cause of intestinal obstruction that is characterized by a thick fibrotic membrane encasing the small intestine like a cocoon. Accurate preoperative diagnosis is often difficult. We present 2 cases of SEP that were diagnosed preoperatively by contrast-enhanced computed tomography scan. A 38-year-old man and a 56-year-old woman were admitted to Daegu Catholic University Medical Center because of recurrent intestinal obstruction. We performed exploratory laparotomy with doubt of the preoperative diagnosis of SEP. We confirmed the diagnosis of SEP on laparotomy and performed adhesiolysis. Both patients recovered successfully and had no signs of recurrence. A better awareness of SEP and its radiological features should lead to more correct preoperative diagnosis and result in more appropriate management, including surgery.

Case report: acute bowel obstruction with an isolated transition point in peritoneal dialysis patients; a presentation of encapsulating peritoneal sclerosis?

BACKGROUND

Encapsulating peritoneal sclerosis (EPS) is classically described as progressive sclerosis and cocooning of the entire peritoneum; however, there has been limited number of reported cases of localized fibrosis as a variant form.

CASE PRESENTATION

We describe two cases of acute bowel obstruction with isolated transition points in the setting of long-term peritoneal dialysis.

CONCLUSION

We postulate that some of the cases of small bowel obstruction with an obvious transition point in long-term peritoneal dialysis patients may represent a unique and localized form of EPS. We aim to emphasize the presence of macroscopic variations in presentation of EPS.

Long-Term Success with Adhesiolysis in Post-Transplant Encapsulating Peritoneal Sclerosis: A Retrospective Case Series of 4 Patients and Review of the Literature

Encapsulating peritoneal sclerosis (EPS) is an occasional and serious complication for peritoneal dialysis (PD) patients for whom no evidence-based management strategies have yet been established. Encapsulating peritoneal sclerosis could appear after kidney transplantation in patients who previously underwent long-term PD. In this report, we present our experience in four PD patients diagnosed with EPS after kidney transplantation. Adhesiolysis provided improvement in their acute clinical conditions and allograft functions, despite the long-term follow-up. Surgical intervention may be a safe modality for this specific group of patients.

Morphological Retrospective Study of Peritoneal Biopsies from Patients with Encapsulating Peritoneal Sclerosis: Underestimated Role of Adipocytes as New Fibroblasts Lineage?

Background. Encapsulating peritoneal sclerosis (EPS) is a rare but serious complication of peritoneal dialysis (PD). Besides the endothelial-to-mesenchymal transition (EMT), recently peritoneal adipocytes emerged as a potential source of fibrosis. We performed immunohistochemistry to approach EMT and to localize peritoneal adipocytes in peritoneal biopsies from PD-related EPS patients. Material and Methods. We investigated tissue expression of podoplanin, cytokeratin AE1/AE3 (mesothelium), calretinin (adipocytes), alpha-smooth muscle actin [α-SMA] (mesenchymal cells), interstitial mononuclear cell inflammation, and neoangiogenesis (CD3, CD4, CD8, CD20, CD68, and CD31 immunostainings, resp.). Results. Three patients (1 man/2 women; 17, 64, and 39 years old, resp.) developed EPS after 21, 90, and 164 months of PD therapy. In patients with EPS, we observed (1) loss of AE1/AE3 cytokeratin+ mesothelial cells without any evidence of migration into the interstitium, (2) disappearance of adipose tissue, (3) diffuse infiltration of calretinin+ cells in the areas of submesothelial fibrosis with a huge number of α-SMA and calretinin+ fusiform cells, and (4) increased vascular density. Conclusion. We report that the involvement of EMT in peritoneal fibrosis is difficult to demonstrate and that the calretinin+ adipocytes might be an underestimated component and a new source of myofibroblasts in peritoneal remodeling during PD-related EPS.

Methylglyoxal Induced Basophilic Spindle Cells with Podoplanin at the Surface of Peritoneum in Rat Peritoneal Dialysis Model

Peritoneal dialysis (PD) is a common treatment for patients with reduced or absent renal function. Long-term PD leads to peritoneal injury with structural changes and functional decline. At worst, peritoneal injury leads to encapsulating peritoneal sclerosis (EPS), which is a serious complication of PD. In order to carry out PD safely, it is important to define the mechanism of progression of peritoneal injury and EPS. We prepared rat models of peritoneal injury by intraperitoneal administration of glucose degradation products, such as methylglyoxal (MGO) or formaldehyde (FA), chlorhexidine gluconate (CG), and talc. In rats treated with MGO, peritoneal fibrous thickening with the appearance of basophilic spindle cells with podoplanin, cytokeratin, and α-smooth muscle actin at the surface of the peritoneum was observed. These cells may have been derived from mesothelial cells by epithelial-to-mesenchymal transition. In FA- or CG-treated rats, the peritoneum was thickened, and mesothelial cells were absent at the surface of the peritoneum. The CG- or MGO-treated rats presented with a so-called abdominal cocoon. In the talc-treated rats, extensive peritoneal adhesion and peritoneal thickening were observed. MGO-induced peritoneal injury model may reflect human histopathology and be suitable to analyze the mechanism of progression of peritoneal injury and EPS.

Encapsulating peritoneal sclerosis is associated with T-cell activation

BACKGROUND

Encapsulating peritoneal sclerosis (EPS) is an excessive fibrotic response of the peritoneum that may occur after long-term peritoneal dialysis (PD). The underlying pathophysiology is poorly understood, but involvement of peritoneal inflammatory T helper 1 cells may be pivotal.

METHODS

Soluble interleukin-2 receptor alpha (sCD25) concentration was measured as a marker for T-cell activation in serum and ascites from EPS patients and various control patient groups. Peritoneal biopsies were stained for the presence of T cells, and T cells isolated from ascites of EPS patients were characterized in detail for differentiation status and cytokine expression.

RESULTS

Serum sCD25 concentrations are significantly and specifically increased in EPS patients compared with haemodialysis, PD and predialysis patients. Peritoneal effluent of stable PD patients contains very low levels of sCD25, while sCD25 levels in ascites of EPS patients are high and indicative of local production. In the years preceding the diagnosis of EPS, the serum sCD25 concentrations increased while remaining at stable levels in control PD patients. The peritoneum and ascites of EPS patients showed a significant influx of T cells with relatively increased numbers of CD4(+) T cells. These T cells were fully differentiated and displayed a T helper 1 cell type with a pro-inflammatory cytokine profile.

CONCLUSIONS

Increased serum sCD25 concentrations and peritoneal lymphocytosis in EPS patients indicate the involvement of activated T cells in the pathophysiology of excessive fibrosis.

CD4-Positive T Cells and M2 Macrophages Dominate the Peritoneal Infiltrate of Patients with Encapsulating Peritoneal Sclerosis

Background

Encapsulating peritoneal sclerosis (EPS) is a severe complication of peritoneal dialysis (PD). Previously, it has been shown that infiltrating CD4-positive T cells and M2 macrophages are associated with several fibrotic conditions. Therefore, the characteristics of the peritoneal cell infiltrate in EPS may be of interest to understand EPS pathogenesis. In this study, we aim to elucidate the composition of the peritoneal cell infiltrate in EPS patients and relate the findings to clinical outcome.

Study Design, Setting, and Participants

We studied peritoneal membrane biopsies of 23 EPS patients and compared them to biopsies of 15 PD patients without EPS. The cellular infiltrate was characterized by immunohistochemistry to detect T cells(CD3-positive), CD4-positive (CD4+) and CD8-positive T cell subsets, B cells(CD20-positive), granulocytes(CD15-positive), macrophages(CD68-positive), M1(CD80-positive), and M2(CD163-positive) macrophages. Tissues were analysed using digital image analysis. Kaplan-Meier survival analysis was performed to investigate the survival in the different staining groups.

Results

The cellular infiltrate in EPS biopsies was dominated by mononuclear cells. For both CD3 and CD68, the median percentage of area stained was higher in biopsies of EPS as opposed to non-EPS patients (p<0.001). EPS biopsies showed a higher percentage of area stained for CD4 (1.29%(0.61-3.20)) compared to CD8 (0.71%(0.46-1.01), p = 0.04), while in the non-EPS group these cells were almost equally represented (respectively 0.28%(0.05-0.83) versus 0.22%(0.17-0.43), p = 0.97). The percentage of area stained for both CD80 and CD163 was higher in EPS than in non-EPS biopsies (p<0.001), with CD163+ cells being the most abundant phenotype. Virtually no CD20-positive and CD15-positive cells were present in biopsies of a subgroup of EPS patients. No relation was found between the composition of the mononuclear cell infiltrate and clinical outcome.

Conclusions

A characteristic mononuclear cell infiltrate consisting of CD4+ and CD163+ cells dominates the peritoneum of EPS patients. These findings suggest a role for both CD4+ T cells and M2 macrophages in the pathogenesis of 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.