Changes in Peritoneal Coagulation and Fibrinolysis after Discontinuation of Chronic Peritoneal Dialysis

♦ Objectives

To study changes in peritoneal function after transfer from chronic peritoneal dialysis (CPD) to hemodialysis (HD), especially the effects on peritoneal coagulation, fibrinolytic markers, and mesothelium.

♦ Design

Prospective observational study.

♦ Setting

A tertiary-care university hospital.

♦ Patients

Nine patients who transferred from CPD to HD were enrolled in the study after giving fully informed consent.

♦ Methods

After transfer to HD, the peritoneal cavity was lavaged with low glucose PD solution once per day through PD catheters left in place. Thrombin–antithrombin III complex (TAT) was measured serially as a marker of peritoneal coagulation. As fibrinolytic markers, fibrinogen/fibrin degradation products (FDP) and plasmin–α2-antiplasmin complex (PIC) were assessed. Cancer antigen 125 (CA125) was measured as a marker of mesothelial cell mass.

♦ Results

Levels of peritoneal TAT and FDP were much higher than plasma levels, indicating high local fibrin turnover. Transfer to HD induced a significant fall in mean peritoneal TAT, from 115.8 ± 52.1 to 60.7 ± 21.8 ng/mL, p < 0.05. Except for 1 patient with a 20-fold increase, mean peritoneal FDP decreased significantly, from 43.6 ± 11.1 to 19.6 ± 3.5 μg/mL, p < 0.05. Mean peritoneal PIC increased significantly, from 1.9 ± 0.4 to 3.9 ± 0.6 μg/mL, p < 0.05. Peritoneal CA125 increased from 156.4 ± 57.3 to 1426.2 ± 389.4 U/mL, p < 0.05.

♦ Conclusions

Peritoneal fibrin turnover was accelerated on CPD and stabilized after transfer to HD. Transfer to HD also induced mesothelial regeneration.

Experimental Animal Models of Encapsulating Peritoneal Sclerosis

Encapsulating peritoneal sclerosis (EPS) is an infrequent, but extremely serious complication of long-term peritoneal dialysis. The cause of EPS is unclear, but the low incidence suggests that it is most likely multifactorial. The elucidation of developmental pathways and predictive markers of EPS would facilitate the identification and management of high-risk patients.

Animal models are often used to define pathways of disease progression and to test strategies for treatment and prevention in the patient population. Ideally such models could help to define the cause of EPS and its developmental pathways, to facilitate the identification of contributing factors and predictive markers, and to provide a system to test therapeutic strategies.

Researchers have studied several rodent models of EPS that rely on chronic chemical irritation (for example, bleach, low-pH solution, chlorhexidine gluconate) to induce peritoneal sclerosis and abdominal encapsulation. Development in all models is progressive, with inflammation giving way to peritoneal fibrosis or sclerosis with accumulating membrane damage, culminating in cocoon formation. Microscopic findings are similar to those proposed as diagnostic criteria for clinical EPS: an initial inflammatory infiltrate and submesothelial thickening, collagen deposition, and activation and proliferation of peritoneal fibroblasts. The potential to block progression of peritoneal sclerosis in these models by anti-inflammatory, antifibrotic, and antiangiogenic agents, and by inhibitors of the renin–angiotensin system have been demonstrated.

Animal models based on clinically relevant risk factors (for example, uremia, peritonitis, and long-term exposure to dialysis solutions) now represent the next step in model development.

Is Normal Saline Harmful to the Peritoneum?

♦ Background

Normal saline (0.9% NaCl) is used during various abdominal surgical interventions and during peritoneal dialysis to rinse the peritoneal cavity. Although no clear clinical evidence exists for the bioincompatibility of normal saline, various experimental studies have suggested that 0.9% NaCl solution can initiate fibrosis of peritoneum.

♦ Material and Methods

We review the data derived from in vitro and in vivo experimental studies demonstrating the cytotoxic effect of 0.9% NaCl and its ability to initiate peritoneal adhesions.

♦ Results

Normal saline reduces the viability and fibrinolytic activity of peritoneal mesothelial cells. Use of normal saline to wash the peritoneal cavity during abdominal operations or after chronic peritoneal dialysis is more likely to produce adhesions than is no irrigation at all. Chronic exposure of the peritoneum to normal saline causes overgrowth of the connective tissue and formation of new blood vessels within that tissue.

Conclusion

♦ Normal saline is a bioincompatible solution that predisposes to the formation of peritoneal adhesions and fibrosis of the peritoneum. A 0.9% NaCl solution should therefore not be used to rinse the peritoneal cavity after interruption of peritoneal dialysis.

Effects of Pentoxifylline on Peritoneal Fibroblasts and Silica-Induced Peritoneal Fibrosis

♦ Background

Peritoneal fibrosis is a long-term complication following continuous ambulatory peritoneal dialysis (CAPD). Peritoneal fibroblasts may play an important role in peritoneal fibrosis. Up to now, the treatment of peritoneal fibrosis in patients with CAPD remains unsatisfactory. Pentoxifylline (PTX) is a xanthine derivative and is used in the treatment of peripheral vascular and cerebrovascular diseases. Several studies have demonstrated that PTX can ameliorate fibrosis of the skin, liver, and kidney.

♦ Objective

To investigate the effect of PTX on in vitro growth and collagen synthesis of human peritoneal fibroblasts (HPFBs), and to evaluate the effects of PTX on silica-induced peritoneal fibrosis in vivo.

♦ Design and Measurements

In the in vitro study, HPFBs were cultured from human omentum. The effect of PTX on the growth of serum-stimulated HPFBs was evaluated by MTT assay. The effect of PTX on the collagen synthesis of HPFB was measured by [3H]-proline incorporation. Expression of type I and type III collagen mRNA was evaluated by Northern blotting. The effects of PTX on matrix metalloproteinase (MMP) activity and cAMP level in HPFBs were measured by immunoassays. In the in vivo study, Wistar rats were randomly divided into five groups. All rats received intraperitoneal (IP) injection of silica suspension (250 mg/100 g body weight) on day 0. The rats of group 1 (control group) were injected with vehicle IP every day for 14 days. The rats of groups 2, 3, and 4 were injected with PTX (4 mg/100 g body weight) IP every day for 3, 7, and 14 days, respectively. The rats in group 5 received an intravenous infusion of PTX (8 mg/100 g body weight) every day for 7 days. On the 15th day after silica injection, all rats were sacrificed. Their parietal and visceral peritoneums were removed and processed for pathology, and the severity of fibrosis was measured and scored. ♦ Results: In vitro, PTX inhibited serum-stimulated HPFB growth (maximum was 93% at 1 mg PTX/mL) in a dose-dependent manner. Collagen synthesis by HPFB was reduced (47% at 1 mg PTX/mL), and collagen I and III mRNA expression in HPFBs was suppressed by PTX. The PTX did not affect the MMP (including MMP-1, MMP-8, and MMP-13) activities of HPFBs. The mechanism of PTX was through increasing cAMP by its phosphodiesterase inhibiting activity. In vivo, the severity of fibrosis was significantly reduced in groups 4 and 5 compared to group 1 ( p < 0.05).

♦ Conclusion

These results suggest that PTX can inhibit growth of and collagen synthesis by HPFBs in vitro. The fibrosis derived from silica-induced peritonitis in vivo was also ameliorated by PTX. Therefore, pentoxifylline may have the potential to be used to treat peritoneal fibrosis in patients on CAPD.

High Glucose Dialysis Solutions Increase Synthesis of Vascular Endothelial Growth Factors by Peritoneal Vascular Endothelial Cells

♦ Objective

Increased peritoneal vasculature has been reported in long-term peritoneal dialysis (PD), and vascular endothelial growth factors (VEGFs) have been found in dialysate. High concentrations of glucose or lactate, glucose degradation products (GDPs), and low pH of dialysis solutions are all possible factors in increased peritoneal VEGF synthesis. In this study, we investigated the effects of high glucose dialysis solutions on VEGF synthesis by peritoneal vascular endothelial cells (PVECs).

♦ Methods

The PVECs were isolated from rat omentum and were incubated for 4 hours in three different culture media [M199 media (control), conventional dialysis solutions containing 4.25% glucose diluted with an equal volume of M199 media (HGD), and M199 media containing 118 mmol/L mannitol as an osmolar control (mannitol)]. Levels of VEGF protein in the culture supernatant were measured by ELISA, and mRNA expression was determined by Northern blot analysis. Data are presented as percent of control.

♦ Results

After incubation for 4 hours, the number of cells did not differ between the 3 groups. Levels of VEGF in culture supernatant were significantly higher in the HGD group (124% ± 19%, p = 0.006) as compared with the control and mannitol (85% ± 10%) groups. The mRNA expression of VEGF appeared to be higher in the HGD group (128% ± 49%) than in the control and mannitol (94% ± 18%) groups.

♦ Conclusion

High glucose dialysis solutions increased VEGF synthesis by PVECs. The relationship between VEGF synthesis by PVECs and neovascularization of the peritoneum observed in long-term peritoneal dialysis patients has to be studied further.

Nutritional Management of Patients Undergoing Surgery following Diagnosis with Encapsulating Peritoneal Sclerosis

Background

Encapsulating peritoneal sclerosis (EPS) is a rare but serious complication of peritoneal dialysis (PD). Gastrointestinal (GI) symptoms affect appetite and dietary intake. Adequate nutrition is especially important if surgical interventions are required.

Aim

To investigate the nutritional management of 23 EPS patients that underwent surgical intervention between 1999 and 2005 at Manchester Royal Infirmary, United Kingdom.

Methods

EPS was recognized by GI symptoms and diagnostically confirmed by laparotomy, computed tomographic scanning, or biopsy.

Results

Mean time on PD was 74 months (interquartile range 42 – 89 months). During the 12 months pre-diagnosis, 65% of the group showed significant weight loss ( p = 0.0001), with 8 patients losing >10% of body weight; 74% of patients experienced significant albumin decrease ( p = 0.001); and 56% of patients experienced GI symptoms during the 6 months pre-diagnosis. Nasogastric (NG) feeding was recommended for 8 patients but continued in only 1. 15 patients (mean albumin 27 g/L) commenced parenteral nutrition (PN); 9 patients recovered, with albumin increasing over the 6-month follow-up. Mean hospital time was 62 days for the group receiving neither NG nor PN, compared with 124.3 for the PN/NG group ( p = 0.04). In patients that died of EPS, albumin continued to fall at 3 months post-diagnosis.

Conclusion

There is currently little guidance for nutritional management of EPS. From this study we recommend ( 1 ) a high level of clinical suspicion for EPS, especially if PD patients have weight loss; ( 2 ) PN may be better than NG feeding but further studies into dual enteral nutrition and PN are needed; ( 3 ) aggressive nutritional supplementation pre- and postoperatively; and ( 4 ) dietitians need to recognize the high risk of refeeding syndrome.

Peritoneal Injury by Methylglyoxal in Peritoneal Dialysis

Background

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, such as ultrafiltration loss. At worst, peritoneal injury leads to encapsulating peritoneal sclerosis, a serious complication of PD. Glucose degradation products contained in PD fluids contribute to the bioincompatibility of conventional PD fluids. Methylglyoxal (MGO) is an extremely toxic glucose degradation product. The present study examined the injurious effect of MGO on peritoneum in vivo.

Methods

Male Sprague–Dawley rats ( n = 6) were administered PD fluids (pH 5.0) containing 0, 0.66, 2, 6.6, or 20 mmol/L MGO every day for 21 days. On day 22, peritoneal function was estimated by the peritoneal equilibration test. Drained dialysate was analyzed for type IV collagen-7S, matrix metalloproteinase (MMP), and vascular endothelial growth factor (VEGF). Histological analysis was also performed.

Results

In rats receiving PD fluids containing more than 0.66 mmol/L MGO, peritoneal function decreased significantly and levels of type IV collagen-7S and MMP-2 in drained dialysate increased significantly. In the 20-mmol/L MGO-treated rats, loss of body weight, expression of VEGF, thickening of the peritoneum, and formation of abdominal cocoon were induced. MMP-2 and VEGF were produced by infiltrating cells in the peritoneum. Type IV collagen was detected in basement membrane of microvessels.

Conclusion

MGO induced not only peritoneal injury but also abdominal cocoon formation in vivo. The decline of peritoneal function may result from reconstitution of microvessel basement membrane or neovascularization.

Four Consecutive Cases of Peritoneal Dialysis-Related Encapsulating Peritoneal Sclerosis Treated Successfully with Tamoxifen

Sclerosing peritonitis is a rare complication of peritoneal dialysis (PD). In encapsulating peritoneal sclerosis (EPS), the most severe form of the disease, the intestine is entrapped in a fibrous tissue, causing intestinal obstruction. Patients are typically seriously ill, with evidence of infection and requirement for parenteral nutrition. A mortality rate of 73% has been reported. There is no established medical treatment and surgery has offered variable results.

Our unit provides renal replacement therapy for a population of about 2 million. The prevalent population of PD patients averages 110. The cumulative PD population since January 1993 is 643, with an EPS prevalence of 0.6%.

Influenced by the first case reported by Allaria in 1999 suggesting benefit of tamoxifen in treating EPS, we have treated with tamoxifen the four consecutive cases of EPS that have presented since 1999. All 4 patients have survived and recovered intestinal function. All showed prior evidence of peritoneal dysfunction with ultrafiltration failure and were characterized by long duration of PD therapy rather than multiple episodes of peritonitis.

We conclude that tamoxifen is a highly promising therapy in EPS, hitherto a usually fatal condition. This description of its efficacy in acutely ill patients with EPS complements its possible prophylactic use in patients with the earlier and milder disease, sclerosing peritonitis. A high index of clinical suspicion for sclerosing peritonitis is desirable, perhaps facilitated by routine screening of at-risk patients.

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.

Imaging and treatment of idiopathic abdominal cocoon in 9 patients

The aim of the current study was to investigate the imaging features of abdominal cocoon (AC), the methods of diagnosis and treatment of AC and improve understanding of AC. To do this, the current study retrospectively analyzed the clinical data and imaging findings of nine patients with AC. The clinical manifestations included intestinal obstruction in six out of the nine cases of AC, which included two cases of bowel strangulation and five cases of soft masses in the abdomen. Imaging features of AC included the following: i) Bowel loops were usually present in a fixed cluster; ii) bowel loops were encapsulated partially or totally by a thickening fibrous membrane-like ‘cocoon’; iii) bowel wall thickened in the ‘cocoon’, and the bowel loops and sac adhered; iv) loculated ascites in the ‘cocoon’; v) abnormal clustering of the mesenteric vasculature, hypoplasia of the omentum majus was present or absent; and vi) Ileus occurred in some cases. The features of a plain abdominal X-ray, a gastrointestinal barium meal series and ultrasonography lacked specificity. The results of CT in eight out of nine cases of AC were consistent with the surgical findings. Surgery was the first choice of therapy. All cases were treated surgically, showing that the bowel loops were encapsulated partially or totally by a thickened fibrous membrane. All cases received operations including partial or total excision of the membrane and enterolysis. In conclusion, CT may be highly valuable in the preoperative diagnosis of AC.

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.

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.

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.

Adoptive transfer of DMSO-induced regulatory T cells exhibits a similar preventive effect compared to an in vivo DMSO treatment for chemical-induced experimental encapsulating peritoneal sclerosis in mice

Encapsulating peritoneal sclerosis (EPS) is a severe complication of peritoneal dialysis (PD). This disease leads to intestinal obstruction with or without peritonitis. The imbalance between the populations of Th17 and regulatory T (Treg) cells (higher Th17 cells and lower Treg cells) is part of the pathogenesis of EPS formation. We demonstrated that dimethyl sulfoxide (DMSO) effectively inhibited autoimmune diabetes recurrence in the islet transplantation of NOD mice via the induction of the differentiation of Treg cells. In this study, we investigated the therapeutic potential of DMSO in the inhibition of EPS formation by a mouse model. Under DMSO treatment, the thickening of the parietal and visceral peritoneum was significantly reduced. The populations of CD4, CD8, and IFN-γ-producing CD4 and CD8 T cells were decreased. The populations of IL-4-producing CD4 T lymphocytes, IL-10-producing CD4 T lymphocytes, CD4 CD69 T lymphocytes and Treg lymphocytes were increased. The expression levels of the cytokines IFN-γ, IL-17a, TNF-α and IL-23, in ascites, were significantly decreased following the DMSO treatment. Furthermore, the differentiation of Treg cells was induced by DMSO from naïve CD4 T cells in vitro, and these cells were adoptively transferred into the EPS mice and significantly prevented EPS formation, exhibiting a comparable effect to the in vivo DMSO treatment. We also demonstrated that the differentiation of Treg cells by DMSO occurred via the activation of STAT5 by its epigenetic effect, without altering the PI3K-AKT-mTOR or Raf-ERK pathways. Our results demonstrated, for the first time, that in vivo DMSO treatment suppresses EPS formation in a mouse model. Furthermore, the adoptive transfer of Treg cells that were differentiated from naïve CD4 T cells by an in vitro DMSO treatment exhibited a similar effect to the in vivo DMSO treatment for the prevention of EPS formation.

Abdominal Cocoon Syndrome: Two Cases of an Anatomical Abnormality

Introduction

Idiopathic sclerosing encapsulating peritonitis or abdominal cocoon syndrome (ACS) is a rare anatomical deformity characterized by the partial or complete encasement of the small intestine with fibrotic peritoneum. 193 cases have been described worldwide. The aim of this study is to present two cases of ACS successfully treated at the Surgical Clinic of the Agios Dimitrios General Hospital in Thessaloniki, Greece.

Presentation of Cases

Two men (55 and 54 years old) presented to the emergency department complaining of abdominal pain, distension, constipation, nausea, and vomiting. Neither of these patients had any previous operations. The computed tomography scan of the first patient showed considerable distension of the small bowel, suggestive of internal herniation. The second case showed distention of the jejunum with no obvious cause. Both patients underwent emergency surgery. Intraoperatively, it was found that a fibrous membrane had completely covered the small intestine of the first patient and the jejunum and part of the large intestine of the second patient. Adhesiolysis and partial excision of the membrane were performed in both cases.

Discussion

ACS is a rare cause of small bowel obstruction. Although conservative management with immunosuppressants and steroids has been described, surgical treatment is the gold standard.

Conclusion

Preoperative clinical suspicion of this disease can help determine the diagnosis and protect surgeons from intraoperative “surprises”.

Surgical Treatment for Encapsulating Peritoneal Sclerosis: 24 Years’ Experience

Background

Encapsulating peritoneal sclerosis (EPS) is a serious complication of long-term peritoneal dialysis. The mortality rate for EPS is high, primarily due to complications related to bowel obstruction. Surgery was previously contraindicated; however, surgical enterolysis is performed for patients in whom bowel obstruction fails to improve.

Methods

This was a retrospective observational study of patients with EPS who received surgical intervention at a single center between November 1993 and October 2017. The severity of intestine damage was characterized by grade-3 peritoneal calcification on abdominal computed tomography (CT) scan and degeneration of the small intestinal wall in surgery.

Results

Two-hundred and forty-three patients with EPS opted for surgery. Among them, 58 had recurrence and required re-surgery; a total of 318 EPS surgeries were performed. Death was related to EPS in 61 patients (25.1%), of whom 15 died postoperatively. Sixty-seven patients (27.6%) died from other causes. The actuarial survival rates at 1, 2, 3, 5, and 8 years after EPS diagnosis were 91%, 83%, 77%, 66%, and 53% respectively. The 50% actuarial survival points after EPS diagnosis and surgery were 104 months and 85 months, respectively. Peritoneal calcification and small intestinal wall degeneration grading showed significant association with the mortality curve for EPS-related death.

Conclusion

Excellent outcomes for EPS are achieved with surgery. The degree of peritoneal deterioration affected the clinical outcomes. Currently, EPS is no longer recognized as a fatal complication.

Encapsulating Peritoneal Sclerosis: The Abdominal Cocoon

Encapsulating peritoneal sclerosis (EPS) is a rare but serious condition that results in (a) encapsulation of bowel within a thickened fibrocollagenous peritoneal membrane and (b) recurrent episodes of bowel obstruction. Although described by various names in the literature, the preferred term is encapsulating peritoneal sclerosis because it best describes the morphologic and histologic changes in this disorder. The etiology of EPS is multifactorial, with a wide variety of implicated predisposing factors that disrupt the normal physiologic function of the peritoneal membrane-prime among these factors being long-term peritoneal dialysis and bacterial peritoneal infections, especially tuberculosis. The clinical features of EPS are usually nonspecific, and knowledge of the radiologic features is necessary to make a specific diagnosis. The findings on radiographs are usually normal. Images from small-bowel follow-through studies show the bowel loops conglomerated in a concertina-like fashion with a serpentine arrangement in a fixed U-shaped configuration. US demonstrates a "cauliflower" appearance of bowel with a narrow base, as well as a "trilaminar" appearance depicted especially with use of high-resolution US probes. CT is the imaging modality of choice and allows identification of the thickened contrast material-enhanced abnormal peritoneal membrane and the encapsulated clumped bowel loops. In addition, CT can potentially help identify the cause of EPS (omental granuloma in tuberculosis), as well as the complications of EPS (bowel obstruction). Conservative medical treatment and surgical therapy early in the course of EPS have been used for management of the condition. The purpose of this article is to review the nomenclature and etiopathogenesis of EPS, describe the multimodality imaging appearances of EPS, including differentiating its features from those of other conditions mimicking EPS, and give an overview of management options. Online DICOM image stacks are available for this article. ^©RSNA, 2018.

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.

Encapsulating Peritoneal Sclerosis in Long-Termed Peritoneal Dialysis Patients

Background

Encapsulating peritoneal sclerosis (EPS) is a rare but serious clinical complication of long-term peritoneal dialysis (PD) patients with high mortality. The purpose of this study was to assess the clinical characteristics of patients with EPS and to search for possible factors useful for EPS prevention and early diagnosis.

Method

This retrospective study was performed in a single dialysis center in Taiwan between August 1990 and April 2014. Overall, a total of 565 patients were included and the medical records of those patients who had developed EPS (EPS group) and those who had not developed EPS (control group) were collected. We compared several factors between these two groups.

Result

In the univariate analysis, EPS was significantly associated with a change of transport state (Delta 2) (p = 0.007), duration of PD (p < 0.001), duration of peritonitis treatment (p = 0.001), number of peritonitis episodes (p = 0.002), and fungus related peritonitis (p = 0.031). After multivariate logistic model analysis, we found that only the duration of PD was independently significantly associated with EPS (p = 0.034). In addition, we used the ROC curve and found that a duration of peritoneal dialysis of about 8.4 years is the best cut-off point to predict EPS occurrence.

Conclusion

In this study, long-termed PD duration is the only strong independent risk factor for EPS development. Total peritonitis times, total peritonitis treatment duration, and marked increased peritoneal D/P_cr ratio were also significantly associated with the duration of PD.

Mesothelial to mesenchyme transition as a major developmental and pathological player in trunk organs and their cavities

The internal organs embedded in the cavities are lined by an epithelial monolayer termed the mesothelium. The mesothelium is increasingly implicated in driving various internal organ pathologies, as many of the normal embryonic developmental pathways acting in mesothelial cells, such as those regulating epithelial-to-mesenchymal transition, also drive disease progression in adult life. Here, we summarize observations from different animal models and organ systems that collectively point toward a central role of epithelial-to-mesenchymal transition in driving tissue fibrosis, acute scarring, and cancer metastasis. Thus, drugs targeting pathways of mesothelium’s transition may have broad therapeutic benefits in patients suffering from these diseases.

Tim Koopmans and Yuval Rinkevich review recent findings linking the mesothelium’s embryonic programs that drive epithelial-to-mesenchyme transition with adult pathologies, such as fibrosis, acute scarring, and cancer metastasis. They highlight new avenues for drug development that would target pathways of the mesothelium’s mesenchymal transition.

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.

Theoretical Morphological Approach to Simple Peritoneal Sclerosis

The term peritoneal sclerosis can be applied to a vast range of peritoneal alterations. At one end of the range we have the slight peritoneal sclerosis constantly associated with peritoneal dialysis, which may be defined as simple sclerosis. Its clinical impact is slight.

The role of glucose in determining peritoneal sclerosis is supported by morphological studies and therefore backed by much biochemical and immunological data.

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.

Incidence and outcomes of encapsulating peritoneal sclerosis (EPS) and factors associated with severe EPS

BACKGROUND

Encapsulating peritoneal sclerosis (EPS) is a rare but serious complication of long-term peritoneal dialysis (PD). However, previous studies reported large variations in its mortality rates that may associate with a different degree of EPS severity. This study reports the incidence and outcomes of EPS and identifies the risk factors associated with severe EPS.

METHODS

We retrospectively analyzed clinical data of EPS patients from 3 medical centers in Taiwan from January 1982 to September 2015, and classified patients as having mild/moderate or severe EPS. Patients with intractable intestinal obstruction/gut-related sepsis that needed surgical intervention or resulted in mortality were in severe EPS group. Follow-up for outcome was through December 31, 2015. Clinical characteristics, peritoneal dialysis (PD)-related parameters, biochemical and imaging results were analyzed and compared between groups.

RESULTS

Fifty-eight of 3202 patients undergoing PD during the study period had EPS (prevalence 1.8%). The incidence of EPS increased for patients on PD for >6-8 years (≤6 yrs. vs. >6-8 yrs., 0.0% vs. 1.8%, p = 0.001). Relative to those on PD for >6-8 years, the risk of EPS significantly increased with PD duration longer than 10 years (>10-12 years vs. >6-8 years: OR: 5.5, 95% CI: 1.7-17.1, p < 0.01). Twenty-three patients fulfilled the criteria for severe EPS. The overall mortality rate of EPS was 35% (20/58), and was 74% (17/23) in the severe EPS group. The average serum levels of C-reactive protein (CRP) and intact-parathyroid hormone (i-PTH), which were checked every 3~6 months within one year before diagnosis of EPS, were higher in severe EPS group than in mild/moderate group (p = 0.02, p = 0.08, respectively). Multivariate analysis revealed severe EPS was independently associated with bowel tethering (based on CT), presentation with bloody ascites, diagnosis of EPS after withdrawal from PD, and i-PTH ≥ 384 pg/mL. Receiver operating characteristic analysis indicated that presentation with 2 or more of the 5 risk factors (EPS diagnosis after PD withdrawal, bloody ascites, bowel tethering, CRP ≥ 29 mg/L, and i-PTH ≥ 384 pg/mL) had a good accuracy (AUC = 0.80, p = 0.001) for prediction of severe EPS.

CONCLUSIONS

The incidence of EPS increases with PD duration. Severe EPS has high mortality rate and is associated with bowel tethering, presentation of bloody ascites, diagnosis after PD withdrawal, and higher serum levels of i-PTH before EPS diagnosis. Having 2 or more of the 5 risk factors can provide a good accuracy for prediction of severe EPS.

Renal Association Clinical Practice Guideline on peritoneal dialysis in adults and children

These guidelines cover all aspects of the care of patients who are treated with peritoneal dialysis. This includes equipment and resources, preparation for peritoneal dialysis, and adequacy of dialysis (both in terms of removing waste products and fluid), preventing and treating infections. There is also a section on diagnosis and treatment of encapsulating peritoneal sclerosis, a rare but serious complication of peritoneal dialysis where fibrotic (scar) tissue forms around the intestine. The guidelines include recommendations for infants and children, for whom peritoneal dialysis is recommended over haemodialysis.Immediately after the introduction there is a statement of all the recommendations. These recommendations are written in a language that we think should be understandable by many patients, relatives, carers and other interested people. Consequently we have not reworded or restated them in this lay summary. They are graded 1 or 2 depending on the strength of the recommendation by the authors, and A-D depending on the quality of the evidence that the recommendation is based on.

Absence of Post-Transplantation Encapsulating Peritoneal Sclerosis after Relatively Short Exposure to Peritoneal Dialysis: Prospective Analysis Using Repeated Abdominal CT Scanning

BACKGROUND

Encapsulating peritoneal sclerosis (EPS) is the most severe complication of peritoneal dialysis (PD). Several retrospective reports published between 2007 and 2009 have suggested an increasing incidence of EPS occurring after kidney transplantation. We conducted a prospective observational study to determine the incidence of post-transplantation EPS and identify possible risk factors.

METHODS

Consecutive PD patients undergoing kidney transplantation between 2009 and 2013 were included. Encapsulating peritoneal sclerosis was defined as gastrointestinal obstruction combined with radiological evidence of EPS. Gastrointestinal symptoms were assessed using a self-administered Gastrointestinal Symptom Rating Scale (GSRS) questionnaire. Abdominal computed tomography (CT) was performed prospectively at 6 and 18 months post-transplantation. The primary end point was EPS during follow-up.

RESULTS

Fifty-three PD patients were included (age 51 ± 14 years). Mean PD duration was 31.3 months. Peritoneal dialysis solutions low in glucose degradation products and icodextrin were used by 86.8% of patients. A fast or average-fast transport status was documented in 83.0%. After a median follow-up of 19 months, complete data of 47 patients were available for analysis. None of the patients developed clinical or radiological signs of EPS. The GSRS score improved from 1.87 to 1.55 (p = 0.024) and body weight increased from 75.9 to 78.3 kg (p = 0.003). Only 1 patient had new onset localized (< 20%) peritoneal thickening on CT 22 months post-transplantation.

CONCLUSION

Post-transplantation EPS did not develop in this cohort of patients with a relatively short time of PD exposure. This suggests that these patients can be transplanted safely without concern for the development of EPS, at least within the follow-up period of 19 months.

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.

Periostin-Binding DNA Aptamer Treatment Ameliorates Peritoneal Dialysis-Induced Peritoneal Fibrosis

Peritoneal fibrosis is a major complication in peritoneal dialysis (PD) patients, which leads to dialysis discontinuation. Periostin, increased by transforming growth factor β1 (TGF-β1) stimulation, induces the expression of extracellular matrix (ECM) genes. Aberrant periostin expression has been demonstrated to be associated with PD-related peritoneal fibrosis. Therefore, the effect of periostin inhibition by an aptamer-based inhibitor on peritoneal fibrosis was evaluated. In vitro, TGF-β1 treatment upregulated periostin, fibronectin, α-smooth muscle actin (α-SMA), and Snail expression and reduced E-cadherin expression in human peritoneal mesothelial cells (HPMCs). Periostin small interfering RNA (siRNA) treatment ameliorated the TGF-β1-induced periostin, fibronectin, α-SMA, and Snail expression and restored E-cadherin expression in HPMCs. Similarly, the periostin-binding DNA aptamer (PA) also attenuated fibronectin, α-SMA, and Snail upregulation and E-cadherin downregulation in TGF-β1-stimulated HPMCs. In mice treated with PD solution for 4 weeks, the expression of periostin, fibronectin, α-SMA, and Snail was significantly increased in the peritoneum, whereas E-cadherin expression was significantly decreased. The thickness of the submesothelial layer and the intensity of Masson's trichrome staining in the PD group were significantly increased compared to the untreated group. These changes were significantly abrogated by the intraperitoneal administration of PA. These findings suggest that PA can be a potential therapeutic strategy for peritoneal fibrosis in PD patients.

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.

Ultrafiltration Failure and Impaired Sodium Sieving During Long-Term Peritoneal Dialysis: More Than Aquaporin Dysfunction?

Fifteen years ago, our group reported the case of a 67-year-old man on peritoneal dialysis for 11 years, in whom ultrafiltration failure and impaired sodium sieving were associated with an apparently normal expression of aquaporin-1 (AQP1) water channels in peritoneal capillaries. At that time, AQP1 dysfunction was suggested as the cause of impaired free-water transport. However, recent data from computer simulations, and structural and functional analysis of the peritoneal membrane of patients with encapsulating peritoneal sclerosis, demonstrated that changes in the peritoneal interstitium directly alter osmotic water transport. In light of these insights, we challenge the initial hypothesis and provide several lines of evidence supporting the diagnosis of encapsulating peritoneal sclerosis in this patient and suggesting that severe peritoneal fibrosis accounted for the loss of osmotic conductance developed during the course of peritoneal dialysis.

An association between transmesenteric internal hernia and abdominal cocoon syndrome: A case report

Introduction

Transmesenteric internal hernia is defined as the herniation of the small intestine from a mesenteric defect in the abdominal cavity, and abdominal cocoon syndrome is the partial or entire encapsulation of the small bowel like the shape of an accordion, by a fibrocollagenous membrane.

Presentation of case

A 32-year old male patient applied with complaints of abdominal pain, nausea, and vomiting bile. Signs visualized in the abdominal computer tomography were as follows: gatto formation of the small intestinal loops and suspected of an internal hernia.In the operation, a membrane was detected encapsulating the entire intestine resembling a tube, making the intestines to appear like an accordion and an opening was present in the small intestinal mesentery. The intestine was separated from the defect, and placed in its normal anatomical position. The defect in the mesentery was closed and the encapsulating membrane was removed from small intestine. Intestinal resection was not required.

Discussion

Internal hernias comprise less than 1% of all intestinal obstructions, and are formed by the herniation of the intestine and mesentery into the opening of the visceral peritoneum or into the recessus. Abdominal cocoon syndrome is a disorder characterized by the partial or total encapsulation of the small intestine by a thick and fibrotic membrane. Preoperative diagnosis is very difficult and is generally diagnosed during laparotomy exploration.

Conclusion

The association of internal herniation and abdominal cocoon syndrome is an extremely rare cause of mechanical intestinal obstruction. If not promptly diagnosed and treated, can lead to serious complications.

Designing Epidemiology Studies to Determine the Incidence and Prevalence of Encapsulating Peritoneal Sclerosis (EPS)

The reported incidence and prevalence of encapsulating peritoneal sclerosis (EPS) varies markedly between North America, Europe, Japan, and Australia. Although this could reflect differences in clinical practice patterns and access to transplantation as there is no current test for early detection, and some patients may present many years after discontinuation of peritoneal dialysis (PD), there are concerns about under-reporting, particularly for those with milder forms. Currently, only PD vintage has been identified as a significant risk factor for developing EPS, although some patients can develop EPS within months of starting PD. As such, there is a need for epidemiological studies to determine the incidence and prevalence of EPS to allow for patient education and counselling in terms of dialysis modality choice and length of treatment. In addition, carefully designed epidemiological studies could potentially allow for the identification of risk factors and bio-markers that could then be used to identify patients at increased risk of developing EPS in the future. Typically, studies to date have been underpowered with inadequate longitudinal follow-up. We review the different types of epidemiological studies and provide information as to the number of patients to be recruited and the duration of follow-up required to determine the incidence and prevalence of EPS.

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.

Risk factors for drainage-requiring ascites after refractory peritonitis in peritoneal dialysis patients

PURPOSE

Refractory peritonitis remains a thorny issue for patients with chronic peritoneal dialysis (PD). Shortly after catheter removal, some patients develop persistent peritoneal inflammation and ascites formation, which require percutaneous drainage for symptom relief. Our study aimed at finding the risk factors for this kind of event.

METHODS

A total of 47 PD patients complicated with refractory peritonitis who underwent catheter removal between January 2009 and December 2011 were enrolled in this study. Data were compared between patients with and without the development of symptomatic ascites requiring drainage during hospitalization.

RESULTS

Among the 47 refractory peritonitis patients, 15 patients developed symptomatic ascites that needed further drainage shortly after catheter removal during hospitalization. The following factors were associated with an increased risk: longer dialysis duration, higher peritoneal Kt/V urea, and a significant rise in serum C-reactive protein (CRP) level after catheter removal. These patients had a prolonged hospital stay (62 vs 21 days, P < 0.001) and a significantly higher risk of recurrent loculated ascites during subsequent 6 months of follow-up (33.3 vs 6.2 %, P = 0.022) compared with patients who did not develop ascites requiring drainage during hospitalization.

CONCLUSION

A significant portion of patients with refractory PD peritonitis experienced ascites requiring drainage shortly after catheter removal, which led to a prolonged hospitalization. Whether routine drain placement at the time of catheter removal for this high-risk group would be of benefit warrants further prospective studies.

Incidence and outcome of encapsulating peritoneal sclerosis

Background

Studies report variation in the incidence and outcomes of encapsulating peritoneal sclerosis (EPS). This study reports the incidence and outcome of EPS cases in a national cohort of peritoneal dialysis (PD) patients.

Methods

The incident cohort of adult patients who started PD between 1 January 2000 and 31 December 2007 in Scotland (n = 1238) was identified from the Scottish Renal Registry. All renal units in Scotland identified potential EPS cases diagnosed from 1 January 2000 to 31 December 2014, by which point all patients had a minimum of 7 years follow-up from start of PD.

Results

By 31 December 2014, 35 EPS cases were diagnosed in the 1238 patient cohort: an overall incidence of 2.8%. The incidence for subgroups with longer PD duration rises exponentially: 1.1% by 1 year, 3.4% by 3 years, 8.8% at 4 years, 9.4% at 5 years and 22.2% by 7 years. Outcomes are poor with mortality of 57.1% by 1 year after diagnosis. Survival analysis demonstrates an initial above-average survival in patients who later develop EPS, which plummets to well below average after EPS diagnosis.

Conclusions

The incidence of EPS is reassuringly low provided PD exposure is not prolonged and this supports ongoing use of PD. However, continuing PD beyond 3 years results in an exponential rise in the risk of developing EPS and deciding whether this risk is acceptable should be made on an individual patient basis.

Case Report of a Patient Undergoing Peritoneal Dialysis with Encapsulating Peritoneal Sclerosis Superimposed With Calciphylaxis

Introduction

Encapsulating peritoneal sclerosis (EPS) is a rare but devastating complication of peritoneal dialysis (PD). Tamoxifen has been generally well-tolerated, even without randomized controlled trials.

Case Presentation

Herein, we report a case of a patient undergoing 12 years of PD who developed EPS and calciphylaxis simultaneously. We also provide a comprehensive discussion about the association between EPS and calciphylaxis. Moreover, although tamoxifen is used in EPS due to its inhibition of fibroblast-transforming growth factor beta (TGFβ) production, it may worsen the calciphylaxis due to a hypercoagulable state.

Conclusions

We suggest avoiding the use of tamoxifen for EPS in patients with superimposed calciphylaxis.

Mast cell involvement in the progression of peritoneal fibrosis in rats with chronic renal failure

AIM

Peritoneal fibrosis is a serious complication in patients with end stage renal disease (ESRD), especially those undergoing long-term peritoneal dialysis therapy. Since the peritoneum is a major site of mast cell accumulation, and since mast cells are known to facilitate the progression of organ fibrosis, they would also contribute to the pathogenesis of peritoneal fibrosis. The aim of this study was to reveal the involvement of mast cells in the progression of peritoneal fibrosis in chronic renal failure.

METHODS

Using a rat model with chronic renal failure (CRF) resulting from 5/6 nephrectomy, we examined the histopathological features of the rat peritoneum and compared them to those of age-matched sham-operated rat peritoneum. By treating the CRF rats with a potent mast cell stabilizer, tranilast, we also examined the involvement of mast cells in the progression of peritoneal fibrosis.

RESULTS

The CRF rat peritoneum was characterized by the wide staining of collagen III and an increased number of myofibroblasts, indicating the progression of fibrosis. Compared to sham-operated rat peritoneum, the number of toluidine blue-stained mast cells was significantly higher in the fibrotic peritoneum of CRF rats. The mRNA expression of fibroblast-activating factors and stem cell factor was significantly higher in peritoneal mast cells obtained from CRF rats than in those obtained from sham-operated rats. Treatment with tranilast significantly suppressed the progression of peritoneal fibrosis in CRF rats.

CONCLUSIONS

This study demonstrated for the first time that the number of mast cells was significantly increased in the fibrotic peritoneum of CRF rats. The proliferation of mast cells and their increased activity in the peritoneum were thought to be responsible for the progression of peritoneal fibrosis.