Encapsulating peritoneal sclerosis: clinical significance and implications

Peritoneal Dialysis-Induced Encapsulating Peritonitis: Diagnostic and Therapeutic Challenges in Women with Benign Gynecological Pathology

Background: Peritoneal sclerosis (PS) and its most severe form, encapsulating PS (EPS), are rare entities that can occur in various procedures (liver transplantation, intraperitoneal chemotherapy) or secondary to medications (beta-blockers); however, PS or EPS typically occur in patients undergoing peritoneal dialysis as a form of renal function substitution. Medical or surgical treatments can be applied, but morbidity and mortality have high rates. This condition typically presents clinically as an intestinal obstruction caused by the inclusion of the intestinal loops in the peritoneal fibrous membrane. Methods: Herein, we present data from a single tertiary surgery center that has dedicated teams for patients receiving dialysis. Over 12 years, we analyzed a group of 63 patients admitted for catheter replacement/removal or for acute surgical pathology. In five cases (7.9%), we diagnosed EPS. Two patients with EPS presented with atypical abdominal pathologies requiring emergency surgery: one case of hemoperitoneum caused by a ruptured ovarian cyst and one case of uterine fibroids and metrorrhagia. Results: The definitive diagnoses were established intraoperatively and by analyzing the morpho-pathological changes in the peritoneum. The possible intraoperative challenges included laborious dissection, difficulties in restoring the correct anatomical landmarks, an increased duration of the surgical intervention and a high rate of incidents and accidents. Conclusions: The aim of the present study was to emphasize the possibility of other surgical pathologies overlapping with EPS, increasing the complexity of the surgical intervention.

Renal hyperparathyroidism- a risk factor in the development of encapsulating peritoneal sclerosis

Background

Encapsulating peritoneal sclerosis (EPS) is a rare complication of prolonged peritoneal dialysis (PD) exposure, characterised by peritoneal thickening, calcification, and fibrosis ultimately presenting with life-threatening bowel obstruction. The presence or role of peritoneal calcification in the pathogenesis of EPS is poorly characterised. We hypothesise that significantly aberrant bone mineral metabolism in patients on PD can cause peritoneal calcification which may trigger the development of EPS. We compared the temporal evolution of bone mineral markers during PD in EPS patients with non-EPS long-term PD controls.

Methods

Linear mixed model and logistic regression analysis were used to compare four-monthly serum levels of calcium, phosphate, parathyroid hormone, and alkaline phosphatase (ALP) over the duration of PD exposure in 46 EPS and 46 controls (PD, non-EPS) patients.

Results

EPS patients had higher mean calcium (2.51 vs. 2.41 mmol/L) and ALP (248.00 vs. 111.13 IU/L) levels compared with controls (p=0.01 and p<0.001 respectively, maximum likelihood estimation). Logistic regression analysis demonstrated that high serum calcium and phosphate levels during PD were associated with a 4.5 and 2.9 fold increase in the risk of developing EPS respectively.

Conclusion

High levels of calcium and phosphate in patients on PD were identified to be risk factors for EPS development. Possible reasons for this may be an imbalance of pro-calcifying factors and calcification inhibitors promoting peritoneal calcification which increases peritoneal stiffness. Mechanical alterations may trigger, unregulated fibrosis and subsequent development of EPS. Improved management of secondary hyperparathyroidism during PD may ultimately diminish the EPS risk.

Peritoneal effluent MicroRNA profile for detection of encapsulating peritoneal sclerosis

BACKGROUND

Encapsulating peritoneal sclerosis (EPS) is a catastrophic complication of peritoneal dialysis (PD) with high mortality. Our aim is to develop a novel noninvasive microRNA (miRNA) test for EPS.

METHODS

We collected 142 PD effluents (EPS: 62 and non-EPS:80). MiRNA profiles of PD effluents were examined by a high-throughput real-time polymerase chain reaction (PCR) array to first screen. Candidate miRNAs were verified by single real-time PCR. The model for EPS prediction was evaluated by multiple logistic regression and machine learning.

RESULTS

Seven candidate miRNAs were identified from the screening of PCR-array of 377 miRNAs. The top five area under the curve (AUC) values with 5 miRNA-ratios were selected using 127 samples (EPS: 56 vs non-EPS: 71) to produce a receiver operating characteristic curve. After considering clinical characteristics and 5 miRNA-ratios, the accuracies of the machine learning model of Random Forest and multiple logistic regression were boosted to AUC 0.97 and 0.99, respectively. Furthermore, the pathway analysis of miRNA associated targeting genes and miRNA-compound interaction network revealed that these five miRNAs played the roles in TGF-β signaling pathway.

CONCLUSION

The model-based miRNA expressions in PD effluents may help determine the probability of EPS and provide further therapeutic opinion for EPS.

Hyperspectral evaluation of vasculature in induced peritonitis mouse models

Imaging of blood vessel structure in combination with functional information about blood oxygenation can be important in characterizing many different health conditions in which the growth of new vessels contributes to the overall condition. In this paper, we present a method for extracting comprehensive maps of the vasculature from hyperspectral images that include tissue and vascular oxygenation. We also show results from a preclinical study of peritonitis in mice. First, we analyze hyperspectral images using Beer-Lambert exponential attenuation law to obtain maps of hemoglobin species throughout the sample. We then use an automatic segmentation algorithm to extract blood vessels from the hemoglobin map and combine them into a vascular structure-oxygenation map. We apply this methodology to a series of hyperspectral images of the abdominal wall of mice with and without induced peritonitis. Peritonitis is an inflammation of peritoneum that leads, if untreated, to complications such as peritoneal sclerosis and even death. Characteristic inflammatory response can also be accompanied by changes in vasculature, such as neoangiogenesis. We demonstrate a potential application of the proposed segmentation and processing method by introducing an abnormal tissue fraction metric that quantifies the amount of tissue that deviates from the average values of healthy controls. It is shown that the proposed metric successfully discriminates between healthy control subjects and model subjects with induced peritonitis and has a high statistical significance.

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.

Traduction des Recommandations de l'ISPD pour l'évaluation du dysfonctionnement de la membrane péritonéale chez l'adulte

Informations concernant cette traductionDans le cadre d’un accord de partenariat entre l’ISPD et le RDPLF, le RDPLF est le traducteur français officiel des recommandations de l’ISPD. La traduction ne donne lieu à aucune compensation financière de la part de chaque société et le RDPLF s’est engagé à traduire fidèlement le texte original sous la responsabilité de deux néphrologues connus pour leur expertise dans le domaine. Avant publication le texte a été soumis à l’accord de l’ISPD. La traduction est disponible sur le site de l’ISPD et dans le Bulletin de la Dialyse à Domicile.Le texte est, comme l’original, libremement téléchargeable sous licence copyright CC By 4.0https://creativecommons.org/licenses/by/4.0/Cette traduction est destinée à aider les professionnels de la communauté francophone à prendre connaissance des recommandations de l’ISPD dans leur langue maternelle. Toute référence dans un article doit se faire au texte original en accès libre :Peritoneal Dialysis International https://doi.org/10.1177/0896860820982218 Dans les articles rédigés pour des revues françaises, conserver la référence à la version originale anglaise ci dessus, mais ajouter «version française  https://doi.org/10.25796/bdd.v4i3.62673"»TraducteursDr Christian Verger, néphrologue, président du RDPLFRDPLF, 30 rue Sere Depoin, 95300 Pontoise – FranceProfesseur Max Dratwa, néphrologueHôpital Universitaire Brugmann – Bruxelles – Belgique

Encapsulating Peritoneal Sclerosis after kidney Transplantation: Success of Medical Treatment

Encapsulating peritoneal sclerosis (EPS) is an infrequent but serious complication of long-term peritoneal dialysis (PD). EPS may become clinically apparent when patients are on PD (classical EPS) or after undergoing kidney transplantation (post-transplantation EPS). This presentation of EPS seems to occur shortly after kidney transplantation in former PD patients. In this report, we present our experience in our first case of patient diagnosed with EPS after kidney transplantation.

Clinical improvement of encapsulating peritoneal sclerosis after challenging course and 6 months of total parenteral nutrition in child with nephronophthisis: a case report

BACKGROUND

Encapsulating peritoneal sclerosis is a rare but potentially lethal complication of long-term peritoneal dialysis that is associated with significant morbidity and mortality. The occurrence of encapsulating peritoneal sclerosis varies worldwide, but is increased in patients maintained on peritoneal dialysis for 5-8 years. The etiology of encapsulating peritoneal sclerosis remains unidentified, and a high index of clinical suspicion is required for diagnosis.

CASE PRESENTATION

We report a 5-year-old Saudi female with end-stage renal disease secondary to nephronophthisis type 2. She underwent peritoneal dialysis for 30 months, with four episodes of peritonitis. She presented with clinical signs of peritonitis. Three days later, she developed septic shock, which required pediatric intensive care unit admission. The peritoneal dialysis catheter was removed because of refractory peritonitis. Her course was complicated by small bowel perforation, and severe adhesions were revealed on abdominal ultrasound and computed tomography, consistent with a diagnosis of EPS. This finding was later confirmed by diagnostic laparotomy performed twice and complicated by recurrent abdominal wall fistula. She received total parenteral nutrition for 6 months and several courses of antibiotics. The patient received supportive treatment including nutritional optimization and treatment for infection. No other treatments, such as immunosuppression, were administered to avoid risk of infection. Following a complicated hospital course, the patient restarted oral intake after 6 months of total parenteral nutrition dependency. Her abdominal fistula resolved completely, and she was maintained on hemodialysis for few years before she received a kidney transplant.

CONCLUSION

When treating patients using peritoneal dialysis, it is important to consider encapsulating peritoneal sclerosis with refractory peritonitis, which is not always easy to identify, particularly if the patient has been maintained on peritoneal dialysis for less than 3 years. Early identification of encapsulating peritoneal sclerosis and appropriate conservative treatment, including nutritional optimization and treatment of infections, are essential to achieve a better prognosis.

ISPD recommendations for the evaluation of peritoneal membrane dysfunction in adults: Classification, measurement, interpretation and rationale for intervention

Lay summary

Peritoneal dialysis (PD) uses the peritoneal membrane for dialysis. The peritoneal membrane is a thin layer of tissue that lines the abdomen. The lining is used as a filter to help remove extra fluid and poisonous waste from the blood. Everybody is unique. What is normal for one person’s membrane may be very different from another person’s. The kidney care team wants to provide each person with the best dialysis prescription for them and to do this they must evaluate the person’s peritoneal lining. Sometimes dialysis treatment itself can cause the membrane to change after some years. This means more assessments (evaluations) will be needed to determine whether the person’s peritoneal membrane has changed. Changes in the membrane may require changes to the dialysis prescription. This is needed to achieve the best dialysis outcomes. A key tool for these assessments is the peritoneal equilibration test (PET). It is a simple, standardized and reproducible tool. This tool is used to measure the peritoneal function soon after the start of dialysis. The goal is to understand how well the peritoneal membrane works at the start of dialysis. Later on in treatment, the PET helps to monitor changes in peritoneal function. If there are changes between assessments causing problems, the PET data may explain the cause of the dysfunction. This may be used to change the dialysis prescription to achieve the best outcomes. The most common problem with the peritoneal membrane occurs when fluid is not removed as well as it should be. This happens when toxins (poisons) in the blood cross the membrane more quickly than they should. This is referred to as a fast peritoneal solute transfer rate (PSTR). Since more efficient fluid removal is associated with better outcomes, developing a personal PD prescription based on the person’s PSTR is critically important. A less common problem happens when the membrane fails to work properly (also called membrane dysfunction) because the peritoneal membrane is less efficient, either at the start of treatment or developing after some years. If membrane dysfunction gets worse over time, then this is associated with progressive damage, scarring and thickening of the membrane. This problem can be identified through another change of the PET. It is called reduced ‘sodium dip’. Membrane dysfunction of this type is more difficult to treat and has many implications for the individual. If the damage is major, the person may need to stop PD. They would need to begin haemodialysis treatment (also spelled hemodialysis). This is a very important and emotional decision for individuals with kidney failure. Any decision that involves stopping PD therapy or transitioning to haemodialysis therapy should be made jointly between the clinical team, the person on dialysis and a caregiver, if requested. Although evidence is lacking about how often tests should be performed to determine peritoneal function, it seems reasonable to repeat them whenever there is difficulty in removing the amount of fluid necessary for maintaining the health and well-being of the individual. Whether routine evaluation of membrane function is associated with better outcomes has not been studied. Further research is needed to answer this important question as national policies in many parts of the world and the COVID-19 has placed a greater emphasis and new incentives encouraging the greater adoption of home dialysis therapies, especially PD. For Chinese and Spanish Translation of the Lay Summary, see Online Supplement Appendix 1.

Key recommendations

Guideline 1:

A pathophysiological taxonomy: A pathophysiological classification of membrane dysfunction, which provides mechanistic links to functional characteristics, should be used when prescribing individualized dialysis or when planning modality transfer (e.g. to automated peritoneal dialysis (PD) or haemodialysis) in the context of shared and informed decision-making with the person on PD, taking individual circumstances and treatment goals into account. (practice point)

Guideline 2a:

Identification of fast peritoneal solute transfer rate (PSTR): It is recommended that the PSTR is determined from a 4-h peritoneal equilibration test (PET), using either 2.5%/2.27% or 4.25%/3.86% dextrose/glucose concentration and creatinine as the index solute. (practice point) This should be done early in the course dialysis treatment (between 6 weeks and 12 weeks) (GRADE 1A) and subsequently when clinically indicated. (practice point)

Guideline 2b:

Clinical implications and mitigation of fast solute transfer: A faster PSTR is associated with lower survival on PD. (GRADE 1A) This risk is in part due to the lower ultrafiltration (UF) and increased net fluid reabsorption that occurs when the PSTR is above the average value. The resulting lower net UF can be avoided by shortening glucose-based exchanges, using a polyglucose solution (icodextrin), and/or prescribing higher glucose concentrations. (GRADE 1A) Compared to glucose, use of icodextrin can translate into improved fluid status and fewer episodes of fluid overload. (GRADE 1A) Use of automated PD and icodextrin may mitigate the mortality risk associated with fast PSTR. (practice point)

Guideline 3:

Recognizing low UF capacity: This is easy to measure and a valuable screening test. Insufficient UF should be suspected when either (a) the net UF from a 4-h PET is <400 ml (3.86% glucose/4.25% dextrose) or <100 ml (2.27% glucose /2.5% dextrose), (GRADE 1B) and/or (b) the daily UF is insufficient to maintain adequate fluid status. (practice point) Besides membrane dysfunction, low UF capacity can also result from mechanical problems, leaks or increased fluid absorption across the peritoneal membrane not explained by fast PSTR.

Guideline 4a:

Diagnosing intrinsic membrane dysfunction (manifesting as low osmotic conductance to glucose) as a cause of UF insufficiency: When insufficient UF is suspected, the 4-h PET should be supplemented by measurement of the sodium dip at 1 h using a 3.86% glucose/4.25% dextrose exchange for diagnostic purposes. A sodium dip ≤5 mmol/L and/or a sodium sieving ratio ≤0.03 at 1 h indicates UF insufficiency. (GRADE 2B)

Guideline 4b:

Clinical implications of intrinsic membrane dysfunction (de novo or acquired): in the absence of residual kidney function, this is likely to necessitate the use of hypertonic glucose exchanges and possible transfer to haemodialysis. Acquired membrane injury, especially in the context of prolonged time on treatment, should prompt discussions about the risk of encapsulating peritoneal sclerosis. (practice point)

Guideline 5:

Additional membrane function tests: measures of peritoneal protein loss, intraperitoneal pressure and more complex tests that estimate osmotic conductance and ‘lymphatic’ reabsorption are not recommended for routine clinical practice but remain valuable research methods. (practice point)

Guideline 6:

Socioeconomic considerations: When resource constraints prevent the use of routine tests, consideration of membrane function should still be part of the clinical management and may be inferred from the daily UF in response to the prescription. (practice point)

A Successful Treatment of Encapsulating Peritoneal Sclerosis in an Adolescent Boy on Long-term Peritoneal Dialysis: A Case Report

Encapsulating peritoneal sclerosis (EPS) is a rare life-threatening complication associated with peritoneal dialysis (PD). EPS is characterized by progressive fibrosis and sclerosis of the peritoneum, with the formation of a membrane and tethering of loops of the small intestine resulting in intestinal obstruction. It is very rare in children. We present a case of a 16-year-old adolescent boy who developed EPS seven years after being placed on continuous ambulatory peritoneal dialysis (CAPD) complicated by several episodes of bacterial peritonitis. The diagnosis was based on clinical, radiological, intraoperative and histopathological findings. The patient was successfully treated with surgical enterolysis. During a 7-year follow-up, there have been no further episodes of small bowel obstruction documented. He still continues to be on regular hemodialysis and is awaiting a deceased donor kidney transplant. EPS is a long-term complication of peritoneal dialysis and is typically seen in adults. Rare cases may be seen in the pediatric population and require an appropriate surgical approach that is effective and lifesaving for these patients.

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.

[Encapsulant peritonitis]

INTRODUCTION

Encapsulating peritonitis is a rare but severe chronic fibrotic condition related to the development of a white fibrous membrane surrounding the digestive tract. Idiopathic forms have been described, however the disease is most often secondary to peritoneal dialysis or more rarely to surgery. Treatment is difficult and not codified.

CASE REPORT

We report here the observation of a 36-year-old patient whose diagnosis of encapsulating peritonitis was made after a long sub-occlusive history, eight years after a gastric ulcer perforation.

DISCUSSION

We discuss the possible etiologies and we present a focus on this rare and little-known entity.

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 pathogenetic role for M1 macrophages in peritoneal dialysis-associated fibrosis

Peritoneal fibrosis (PF) is a frequent complication of peritoneal dialysis (PD) accompanied by the infiltration of inflammatory cells. Recently, the function of macrophages in an inflammatory microenvironment during PD remains unknown. This study aimed to elucidate the role of distinct macrophage phenotypes in the progression of PF through macrophage depletion in a peritoneal dialysis-induced mouse model. After injection of 200 μl liposomal clodronate (LC) at the start of instillation PD fluids (PDFs), mice were injected with 100 μL LC every 4 days after the first time injection for longer macrophage depletion, while control mice were co-treated with PBS liposomes. For macrophages transfusion,primary macrophages (M0) were stimulated into M1 and M2 macrophages and transfuritoneal fibrosis (PF) is a frequent complication of peritoneal dialysis (PD) accompanied by the infiltration of inflammatory cells. Recently, the function of macrophages in an inflammatory microenvironment during PD remains unknown. This study aimed to elucidate the role of distinct macrophage phenotypes in the progression of PF through macrophage depletion in a peritoneal dialysis-induced mouse model. After injection of 200 μl liposomal clodronate (LC) at the start of instillation PD fluids (PDFs), mice were injected with 100 μL LC every 4 days after the first time injection for longer macrophage depletion, while control mice were co-treated with PBS liposomes. For macrophages transfusion,primary macrophages (M0) were stimulated into M1 and M2 macrophages and transfused into the mice the next day after each LC injection. Mice were sacrificed after 6 weeks of PDFs treatment for the assessment of histological changes, ECM deposition and peritoneal ultrafiltration function. Systemic monocyte/macrophage depletion resulted in less severe structural alterations, including thickening and cubic transformation of mesothelial cells, fibrin deposition, fibrous capsule formation, and interstitial fibrosis. A strong reduction of alpha-smooth muscle actin (α-SMA) and fibronectin expression, as well as an increased E-cadherin expression was also observed, indicating an overall inhibition of peritoneal fibrosis in macrophages depletion mice.M1 macrophage reperfusion showed a significant increase in histological damages, ECM deposition and peritoneal ultrafiltration functional decline compared with those of the M2 and control groups. TLR4 expression was enhanced in M1 macrophage-treated group. These results suggest that M1 macrophages are an important mediator of peritoneal fibrosis.

The enigma of primary and secondary encapsulating peritoneal sclerosis

Background

Encapsulating Peritoneal Sclerosis (EPS) describes a variety of diseases that are frequently confused with different names and different etiopathogeneses. The aim of this article is to report personal experience of focusing on correct classification and the status of current diagnosis and treatment.

Methods

A retrospective analysis was performed. Age, sex, ethnic origin, past medical history, symptoms and their duration, radiological tools and signs, laboratory tests, preoperative diagnosis, surgical approach, intraoperative findings, pathological findings, hospital stay, morbidity and mortality were studied.

Results

A total of seven patients, including six males and one female, aged from 24 to 72 years were observed. Four patients had recurrent abdominal colic pain for 3 months, 1, 2 and 9 years; two patients also reported recurrent attacks but without any specification of the duration. All seven patients presented at the emergency department with abdominal pain that was mainly diffused over the entire abdomen. Six patients were submitted to a CT scan. Only in two patients was the diagnosis of EPS made preoperatively. All seven patients were submitted to open surgery. The hospital stay was between 4 and 60 days. One patient had morbidity, and one patient died of MOF.

Conclusions

Currently, the correct identification of EPS is more easily possible than in the past, but the diagnosis is still a challenge. Surgery must be performed as soon as possible to avoid a poorer quality of life.

HL156A, a novel AMP-activated protein kinase activator, is protective against peritoneal fibrosis in an in vivo and in vitro model of peritoneal fibrosis

HL156A is a novel AMP-activated protein kinase (AMPK) activator. We aimed to investigate the protective mechanism of HL156A against peritoneal fibrosis (PF) in in vivo and in vitro models. The rat PF model was induced by daily intraperitoneally injection of chlorhexidine (CHX) solution containing 0.1% CHX gluconate and 15% ethanol for 4 wk. The rats in the treatment group were treated with HL156A (1 mg·kg−1·day−1). Control rats were injected with vehicle alone. In vitro, cultured rat peritoneal mesothelial cells (RPMCs) were treated with either high glucose (HG; 50 mM), normal glucose (NG; 5 mM), NG+HL156A, or HG+HL156A. HL156A in supplemented rats ameliorated peritoneal calcification, cocoon formation, bowel obstruction, and PF. Immunohistochemistry showed reduced fibronectin accumulation in the peritoneum of HL156A-treated rats compared with those injected with CHX alone. HL156A treatment of RPMCs inhibited HG-induced myofibroblast transdifferentiation and markers of epithelial-mesenchymal transition (EMT). Moreover, HL156A ameliorated HG-induced transforming growth factor-β1, Smad3, Snail, and fibronectin expression in the RPMCs via AMPK upregulation. These results suggest that HL156A exhibits a protective effect in PF progression. Further research is warranted to seek the therapeutic potential of HL156A as an antifibrotic agent in peritoneal dialysis patients.

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.

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.

Living with encapsulating peritoneal sclerosis (EPS): the patient's perspective

BACKGROUND

Although relatively rare, encapsulating peritoneal sclerosis (EPS) is nonetheless a major concern within the renal community. Risk of developing EPS is associated with long-term peritoneal dialysis (PD). High mortality was previously reported, although surgery has since improved outcomes. Research into EPS focuses on imaging and early detection methods, genetics, biomarkers and preventive strategies. No previous studies have examined patients' experiences of EPS.

AIMS

The aim of the present study was to explore the experience of patients who have undergone surgery for EPS in one center in the North of England.

METHODS

A qualitative phenomenological approach, involving in-depth interviews, was adopted. Nine participants were recruited out of a total of 18 eligible. Most participants were interviewed twice over a 12-month period (October 2009 to October 2010).

ANALYSIS

Interpretive data analysis was conducted, following the philosophical tradition of hermeneutics, to draw out themes from the data. Data collection and analysis took place concurrently and participants were sent a summary of their first interview to allow a period of reflection prior to the subsequent interview.

RESULTS

EPS presented the most serious challenge participants had faced since developing chronic kidney disease (CKD). Three major themes were identified, each with subcategories. The key issues for patients were related to identification of early symptoms and lack of understanding. The patients' sense of 'not being heard' by health care professionals led to a loss of trust and enhanced their feelings of uncertainty. The enormity of the surgery, the suffering, and what they had to endure had an enormous impact, but an overriding aspect of this experience was also the loss they felt for their independence and for the PD therapy over which they had control.

CONCLUSIONS

The findings of this study highlight a number of important issues relevant to clinical practice, including lack of information and understanding of EPS, particularly its early symptoms At the time patients transfer from peritoneal to hemodialysis, the provision of adequate information about the risks and potential early signs of EPS may not only improve their experiences, but may also assist in early detection.

Encapsulating peritoneal sclerosis in children

Encapsulating peritoneal sclerosis (EPS) is a rare but extremely serious complication of peritoneal dialysis (PD). While EPS has been well recognized in adults on long-term PD, and children can spend many years on PD before a transplant becomes available, only a small number of children with EPS have been described. Two European pediatric registries have recently reported on the prevalence, potential risk factors and outcomes of EPS in children. Although the prevalence of EPS is comparable to that published in adult registries, the outcome of pediatric EPS is significantly better and carries a lower mortality. All studies have shown a greater risk of EPS with a longer dialysis vintage, but it is not known why some individuals are susceptible to EPS development. In this review we discuss current views on the epidemiology, pathogenesis and management strategies for EPS. The hope of the authors is that this review will alert pediatric nephrologists to this rare but extremely serious complication of chronic PD. In the future, collaborative research and the establishment of a pediatric EPS registry may be of importance in helping pediatric nephrologists to recognize the early warning signs of EPS development and thereby to develop strategies for its prevention and optimal management.

Effect of DNA demethylation in experimental encapsulating peritoneal sclerosis

Encapsulating peritoneal sclerosis (EPS) involves excessive peritoneal fibrosis in patients on peritoneal dialysis, eventually leading to visceral constriction and bowel obstruction. Few studies have investigated epigenetic mechanisms relating to EPS. Here we evaluated the therapeutic effects of DNA demethylation in experimental EPS. Experimental EPS was induced by intraperitoneal injection of 0.1% chlorhexidine gluconate (CG) and 15% ethanol in non-uremic male Sprague-Dawley (SD) rats. Rats were divided into three groups: group C (N=5) with saline injection only, group CG (N=7) with EPS induction for 4 weeks, and chlorhexidine gluconate and azacytidine (CGA) treated group (N=7) with EPS induction for 4 weeks and 5'-azacytidine injection for the last 2 weeks. Morphometric analysis of peritoneum and immunohistochemical staining for type 1 collagen and α-smooth muscle actin (α-SMA) were performed. Expressions of transforming growth factor-β (TGF-β), fibroblast-specific protein 1 (FSP1), and DNA methyltransferase 1 (DNMT1) were analyzed by Western blot. Methylation-specific polymerase chain reaction (PCR) for Ras GTPase activating-like protein 1 (RASAL1) was performed with measurement of RASAL1 protein expression. Parietal peritoneal thickness and the number of vessels in omental tissue were significantly decreased in group CGA compared to group CG, as were the expressions of type 1 collagen, α-SMA, TGF-β, and FSP1. DNMT1 was significantly increased in group CG, and reduced in group CGA. RASAL1 hypermethylation was associated with decreased RASAL1 protein expression in group CG, which was reversed in group CGA. DNA demethylation by 5'-azacytidine treatment improved pathologic changes of the peritoneum in experimental EPS, and was associated with reversal of increased DNMT1 expression and RASAL1 hypermethylation.

New insights into therapeutic strategies for the treatment of peritoneal fibrosis: learning from histochemical analyses of animal models

Encapsulating peritoneal sclerosis (EPS) is a fatal complication that can occur in patients undergoing long-term peritoneal dialysis. It is characterized by bowel obstruction and marked sclerotic thickening of the peritoneal membrane. Although the mechanisms underlying the development of EPS are complex, angiogenesis, inflammation, and peritoneal fibrosis are known to be essential factors. Now, several animal models that exhibit EPS have pathophysiology similar to that of human EPS and have been proposed for use in research to provide insights into it. Recent histochemical methods also help us to understand the pathophysiology of EPS. Advances in basic research based on the findings in those animal models have enabled the development of several strategies for the prevention and treatment of EPS. We describe here interventional studies in some animal models for peritoneal fibrosis, one of the histological disorders findings characteristic to EPS, and we highlight the need for a sophisticated animal model that closely resembles human conditions.

Mesenchymal Conversion of Mesothelial Cells Is a Key Event in the Pathophysiology of the Peritoneum during Peritoneal Dialysis

Peritoneal dialysis (PD) is a therapeutic option for the treatment of end-stage renal disease and is based on the use of the peritoneum as a semipermeable membrane for the exchange of toxic solutes and water. Long-term exposure of the peritoneal membrane to hyperosmotic PD fluids causes inflammation, loss of the mesothelial cells monolayer, fibrosis, vasculopathy, and angiogenesis, which may lead to peritoneal functional decline. Peritonitis may further exacerbate the injury of the peritoneal membrane. In parallel with these peritoneal alterations, mesothelial cells undergo an epithelial to mesenchymal transition (EMT), which has been associated with peritoneal deterioration. Factors contributing to the bioincompatibility of classical PD fluids include the high content of glucose/glucose degradation products (GDPs) and their acidic pH. New generation low-GDPs-neutral pH fluids have improved biocompatibility resulting in better preservation of the peritoneum. However, standard glucose-based fluids are still needed, as biocompatible solutions are expensive for many potential users. An alternative approach to preserve the peritoneal membrane, complementary to the efforts to improve fluid biocompatibility, is the use of pharmacological agents protecting the mesothelium. This paper provides a comprehensive review of recent advances that point to the EMT of mesothelial cells as a potential therapeutic target to preserve membrane function.

Encapsulating peritoneal sclerosis--correlation of radiological findings at CT with underlying pathogenesis

Encapsulating peritoneal sclerosis (EPS) is a rare entity most commonly associated with peritoneal dialysis (PD). Several imaging features at computed tomography (CT) are common to many diseases; however, appreciation of the features unique to this condition interpreted with the appropriate clinical findings is crucial to diagnosis.

Post-transplantation encapsulating peritoneal sclerosis without inflammation or radiological abnormalities

Background

Post-transplantation encapsulating peritoneal sclerosis (EPS) causing bowel obstruction has been identified as a serious complication after kidney transplantation in patients previously treated with peritoneal dialysis. Systemic inflammation and abnormalities on an abdominal computed tomography (CT) scan are important hallmarks of EPS. To our knowledge, this is the first report of a case being diagnosed with late-onset post-transplantation EPS without systemic inflammation or abnormalities on a CT scan which could only be diagnosed by laparotomy.

Case presentation

A 59-year old female presented because of symptoms of bowel obstruction 33 months after kidney transplantation. The patient had a 26-month history of peritoneal dialysis before her first kidney transplantation and was treated with peritoneal dialysis for 4 years before undergoing a second kidney transplantation. Physical examination was unremarkable and laboratory tests showed no signs of systemic inflammation (C-reactive protein <1 mg/L). An abdominal CT scan did not reveal any abnormalities fitting the diagnosis of EPS, except a “feces sign”. Given the severity of the progressive symptoms, a diagnostic laparotomy was performed, visualizing a classical EPS. Total peritonectomy and enterolysis were performed, leading to restoration of peristalsis.

Conclusion

EPS may occur several years after kidney transplantation in the absence of inflammation and typical radiological abnormalities. Obtaining a diagnosis of post-transplantation EPS is challenging, however, a low threshold for surgical exploration in case of high clinical suspicion and negative findings on the CT scan is mandatory.

Kidney Disease: Improving Global Outcomes guidelines on anaemia management in chronic kidney disease: a European Renal Best Practice position statement

Recently, the Kidney Disease: Improving Global Outcomes (KDIGO) group has produced comprehensive clinical practice guidelines for the management of anaemia in CKD patients. These guidelines addressed all of the important points related to anaemia management in CKD patients, including therapy with erythropoieis stimulating agents (ESA), iron therapy, ESA resistance and blood transfusion use. Because most guidelines were 'soft' rather than 'strong', and because global guidelines need to be adapted and implemented into the regional context where they are used, on behalf of the European Renal Best Practice Advisory Board some of its members, and other external experts in this field, who were not participants in the KDIGO guidelines group, were invited to participate in this anaemia working group to examine and comment on the KDIGO documents in this position paper. In this article, the group concentrated only on those guidelines which we considered worth amending or adapting. All guidelines not specifically mentioned are fully endorsed.

Transcriptional patterns in peritoneal tissue of encapsulating peritoneal sclerosis, a complication of chronic peritoneal dialysis

Encapsulating peritoneal sclerosis (EPS) is a devastating complication of peritoneal dialysis (PD), characterized by marked inflammation and severe fibrosis of the peritoneum, and associated with high morbidity and mortality. EPS can occur years after termination of PD and, in severe cases, leads to intestinal obstruction and ileus requiring surgical intervention. Despite ongoing research, the pathogenesis of EPS remains unclear. We performed a global transcriptome analysis of peritoneal tissue specimens from EPS patients, PD patients without EPS, and uremic patients without history of PD or EPS (Uremic). Unsupervised and supervised bioinformatics analysis revealed distinct transcriptional patterns that discriminated these three clinical groups. The analysis identified a signature of 219 genes expressed differentially in EPS as compared to PD and Uremic groups. Canonical pathway analysis of differentially expressed genes showed enrichment in several pathways, including antigen presentation, dendritic cell maturation, B cell development, chemokine signaling and humoral and cellular immunity (P value<0.05). Further interactive network analysis depicted effects of EPS-associated genes on networks linked to inflammation, immunological response, and cell proliferation. Gene expression changes were confirmed by qRT-PCR for a subset of the differentially expressed genes. EPS patient tissues exhibited elevated expression of genes encoding sulfatase1, thrombospondin 1, fibronectin 1 and alpha smooth muscle actin, among many others, while in EPS and PD tissues mRNAs encoding leptin and retinol-binding protein 4 were markedly down-regulated, compared to Uremic group patients. Immunolocalization of Collagen 1 alpha 1 revealed that Col1a1 protein was predominantly expressed in the submesothelial compact zone of EPS patient peritoneal samples, whereas PD patient peritoneal samples exhibited homogenous Col1a1 staining throughout the tissue samples. The results are compatible with the hypothesis that encapsulating peritoneal sclerosis is a distinct pathological process from the simple peritoneal fibrosis that accompanies all PD treatment.

Periostin: a matricellular protein involved in peritoneal injury during peritoneal dialysis

BACKGROUND

Periostin is a matricellular protein involved in tissue remodeling through the promotion of adhesion, cell survival, cellular dedifferentiation, and fibrogenesis. It can be induced by transforming growth factor beta and high glucose concentrations. We hypothesized that this protein might be expressed in the peritoneal cavity of patients on peritoneal dialysis (PD) and even more in patients with signs of encapsulating peritoneal sclerosis (EPS).

METHOD

In this retrospective study, we included peritoneal biopsies from patients on PD with EPS (n = 7) and without signs of EPS (n = 10), and we compared them with biopsies taken during hernia repair from patients not on PD (n = 11) and during various procedures from uremic patients not on PD (n = 6). Periostin was localized by immunohistochemistry, scored semiquantitatively, and quantified by morphometry. Periostin protein concentrations were measured by ELISA in dialysates from 15 patients. Periostin messenger RNA was quantified in vitro in peritoneal fibroblasts.

RESULTS

In control biopsies, periostin was present in the walls of larger arteries and focally in extracellular matrix in the submesothelial zone. Patients on PD demonstrated interstitial periostin in variable amounts depending on the severity of submesothelial fibrosis. In EPS, periostin expression was very prominent in the sclerosis layer. The area of periostin was significantly larger in EPS biopsies than in control biopsies, and the percentage of periostin-positive area correlated with the thickness of the submesothelial fibrosis zone. Periostin concentrations in dialysate increased significantly with time on PD in patients without signs of EPS; in patients with EPS, periostin concentrations in dialysate were low and demonstrated the smallest increase with time. In vitro, periostin was found to be strongly expressed by peritoneal fibroblasts.

CONCLUSION

Periostin is strongly expressed by fibroblasts and deposited in the peritoneal cavity of patients with EPS and with simple peritoneal fibrosis on PD. This protein might play a role in the progression of peritoneal injury, and low levels of periostin after prolonged time on PD might be a marker of EPS.

The spectrum of podoplanin expression in encapsulating peritoneal sclerosis

Encapsulating peritoneal sclerosis (EPS) is a life threatening complication of peritoneal dialysis (PD). Podoplanin is a glycoprotein expressed by mesothelial cells, lymphatic endothelial cells, and myofibroblasts in peritoneal biopsies from patients with EPS. To evaluate podoplanin as a marker of EPS we measured podoplanin mRNA and described the morphological patterns of podoplanin-positive cells in EPS. Included were 20 peritoneal biopsies from patients with the diagnosis of EPS (n = 5), patients on PD without signs of EPS (n = 5), and control patients (uremic patients not on PD, n = 5, non-uremic patients n = 5). EPS patient biopsies revealed significantly elevated levels of podoplanin mRNA (p<0.05). In 24 peritoneal biopsies from patients with EPS, podoplanin and smooth muscle actin (SMA) were localized by immunohistochemistry. Four patterns of podoplanin distribution were distinguishable. The most common pattern (8 of 24) consisted of organized, longitudinal layers of podoplanin-positive cells and vessels in the fibrotic zone (“organized” pattern). 7 of 24 biopsies demonstrated a diffuse distribution of podoplanin-positive cells, accompanied by occasional, dense clusters of podoplanin-positive cells. Five biopsies exhibited a mixed pattern, with some diffuse areas and some organized areas ("mixed"). These contained cuboidal podoplanin-positive cells within SMA-negative epithelial structures embedded in extracellular matrix. Less frequently observed was the complete absence of, or only focal accumulations of podoplanin-positive fibroblasts outside of lymphatic vessels (podoplanin “low”, 4 of 24 biopsies). Patients in this group exhibited a lower index of systemic inflammation and a longer symptomatic period than in EPS patients with biopsies of the "mixed" type (p<0.05). In summary we confirm the increased expression of podoplanin in EPS, and distinguish EPS biopsies according to different podoplanin expression patterns which are associated with clinical parameters. Podoplanin might serve as a useful adjunct to the morphological workup of peritoneal biopsies.

Efficacy and morbidity of surgical therapy in late-stage encapsulating peritoneal sclerosis

BACKGROUND

Encapsulating peritoneal sclerosis (EPS) is a rare but devastating complication of peritoneal dialysis composed of chronic abdominal pain, chronic ileus, and severe malnutrition. Operative therapy for EPS is a complex procedure, including perionectomy and enterolysis (PEEL). In contrast to simple adhesiolysis, PEEL comprises a restitution of intestinal passage and prevention of recurrent disease by decapsulation and partial deserosation.

METHODS

We reviewed the treatment of patients with EPS at our referral center regarding perioperative morbidity, mortality, and long-term outcome. Only patients who underwent PEEL were included. Preoperative general status was ascertained by APACHE-II score and body mass index. Postoperative morbidity was stratified into minor and major complications.

RESULTS

Between the years 2003 and 2010, 26 of 45 patients with late-stage EPS underwent PEEL. Median age was 54 years, APACHE-II score was 15, and body mass index was 21 kg/m². To achieve intestinal function, 9 bowel resections with immediate anastomoses were necessary. Eleven patients (37%) received a complete parietal peritonectomy. Overall morbidity was 44%, with minor complications in 2 patients (7%) and major complications in 11 patients (31%). Three patients (10%) died within the first year after operative treatment.

CONCLUSION

PEEL is a treatment option that can be performed with low mortality and acceptable morbidity. It is a precondition that these patients are treated in specialized referral centers.

Prevalence and predictors of the sub-target Hb level in children on dialysis

BACKGROUND

Anaemia is a common and potentially treatable co-morbidity of end-stage renal disease. We aimed to determine the prevalence of the sub-target haemoglobin (Hb) level among European children on dialysis and to identify factors associated with a low Hb level.

METHODS

From the European Society for Paediatric Nephrology (ESPN)/European Renal Association-European Dialysis Transplant Association (ERA-EDTA) registry, data were available on 2351 children between 1 month and 18 years of age, totalling 5546 measurements from 19 countries.

RESULTS

The mean Hb level was 10.8 g/dL (5th-95th percentiles, 7.4-13.9). Among those above 2 years of age, the mean Hb level was 10.9 g/dL (11.4% below 8.5 g/dL), while it was 10.3 g/dL among those below 2 years (11.2% below 8.0 g/dL). A total of 91.2% of the patients were on an erythropoiesis-stimulating agent (ESA). Hb levels increased with age and were higher in peritoneal dialysis compared with haemodialysis patients. Patients with congenital anomalies of the kidney and urinary tract showed the highest Hb levels, and those with cystic kidney diseases or metabolic disorders the lowest ones. Ferritin levels between 25 and 50 ng/mL were associated with the highest Hb levels. We found a weak inverse association between parathyroid hormone (PTH) and Hb. Whereas standardized blood pressure (BP) was not elevated in patients with above-target Hb, elevated systolic BP z-score was noted in those with sub-target Hb levels.

CONCLUSIONS

Sub-target Hb levels remain common in children on dialysis, in spite of virtually all children being treated with ESA; although we cannot exclude under-dosing. Optimal ferritin levels seemed to be slightly lower in children (25-50 ng/mL) than those in adults. Other risk factors for sub-target Hb are dialysis modality and a high PTH level.

Encapsulating peritoneal sclerosis

Would you recognize this condition?

Proof-of-principle study to detect metabolic changes in peritoneal dialysis effluent in patients who develop encapsulating peritoneal sclerosis

BACKGROUND

Prolonged peritoneal dialysis (PD) therapy can result in the development of encapsulating peritoneal sclerosis (EPS), characterized by extensive sclerosis of the peritoneum with bowel adhesions often causing obstruction.

METHODS

As a proof-of-principle study, holistic profiling of endogenous metabolites has been applied in a prospective collection of PD effluent collected in multiple UK renal centres over 6 years in order to investigate metabolic differences in PD effluent between PD therapy patients who later developed clinically defined EPS (n = 11) and controls, who were matched for PD vintage, age and gender (n = 11).

RESULTS

'Fit-for-purpose' analytical methods employing gas chromatography-mass spectrometry (MS), direct injection MS and quality control samples were developed and validated. These methods were applied in a proof-of-principle study to define metabolic differences in PD effluent related to subsequent development of EPS. Changes in amino acids, amines and derivatives, short-chain fatty acids and derivatives and sugars were observed prior to EPS developing, and changes in the metabolomic profiles could be detected.

CONCLUSION

There is potential for applying metabolic profiles to identify patients at risk of developing EPS although long-term prospective studies with larger patient cohorts are required.

Encapsulating peritoneal sclerosis: the state of affairs

Encapsulating peritoneal sclerosis (EPS) is a severe complication of long-term peritoneal dialysis (PD) with a 50% mortality rate. EPS is characterized by progressive and excessive fibrotic thickening of the peritoneum, leading to encapsulation of the bowels and intestinal obstruction. At present, EPS cannot be detected with certainty during its early stages; however, a progressive loss of ultrafiltration capacity often precedes its development. Studies that attempted to elucidate the pathogenesis of EPS have shown that the duration of exposure to PD fluids is the most important risk factor for EPS, and that young age and possibly the effects of peritonitis are additional contributory factors. The pathophysiology of EPS is probably best described as a multiple-hit process with a central role for transforming growth factor β. A form of EPS that develops shortly after kidney transplantation has also been recognized as a distinct clinical entity, and may be a common form of EPS in countries with a high transplantation rate. Criteria have been developed to identify EPS by abdominal CT scan at the symptomatic stage, but further clinical research is needed to identify early EPS in asymptomatic patients, to clarify additional risk factors for EPS and to define optimal treatment strategies.

Imaging in encapsulating peritoneal sclerosis

Encapsulating peritoneal sclerosis (EPS) is a rare but very severe complication of long-term peritoneal dialysis (PD). Since the first reports on this disease in the eighties, several imaging techniques have been used for its diagnosis. Because of the rarity of this condition, uniformity in modality and protocols for abdominal imaging for diagnosis has been lacking overtime. Nowadays, computed tomography (CT) is most often used. In this review, we provide an overview of all imaging modalities that have been used overtime to diagnose EPS as a late complication of PD. Imaging features characteristic for EPS and advantages as well as shortcomings of all modalities are discussed. We believe that when EPS is suspected, CT with contrast enhancement should be the modality of first choice in clinical practice.

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.

Initial observations using a novel "cine" magnetic resonance imaging technique to detect changes in abdominal motion caused by encapsulating peritoneal sclerosis

Encapsulating peritoneal sclerosis (EPS) is an uncommon complication of peritoneal dialysis (PD), with high mortality and morbidity. The peritoneum thickens, dysfunctions, and forms a cocoon that progressively "strangulates" the small intestine, causing malnutrition, ischemia, and infarction. There is as yet no reliable noninvasive means of diagnosis, but recent developments in image analysis of cine magnetic resonance imaging for the recognition of adhesions offers a way forward. We used this protocol before surgery in 3 patients with suspected EPS. Image analysis revealed patterns of abdominal movement that were markedly different from the patterns in healthy volunteers. The volunteers showed marked movement throughout the abdomen; in contrast, movement in EPS patients was restricted to just below the diaphragm. This clear difference provides early "proof of principle" of the approach that we have developed.