Long-term Peritoneal Dialysis Research Articles

Prognosis and factors related to severe secondary hyperparathyroidism in long-term peritoneal dialysis patients

Secondary hyperparathyroidism (SHPT) can progress to severe SHPT (sSHPT), which affects the survival rate and quality of life of patients. This retrospective cohort study investigated risk factors for sSHPT and the association between SHPT and mortality (all-cause and infection-related) among 771 clinically stable patients (421 male patients; mean age, 51.2 years; median dialysis vintage, 28.3 months) who underwent >3 months of regular peritoneal dialysis (PD) between January 2013 and March 2021. The sSHPT and non-sSHPT groups comprised 75 (9.7%) (median progression, 35 months) and 696 patients, respectively. sSHPT was defined as a serum intact parathyroid hormone (PTH) level >800 pg/mL observed three times after active vitamin D pulse therapy. The influence of sSHPT on the prognosis of and risk factors for sSHPT progression were evaluated using logistic and Cox regression analyses. After adjusting for confounding factors, higher (each 100-pg/mL increase) baseline PTH levels (95% confidence interval (CI) 1.206–1.649, p < .001), longer (each 1-year increase) dialysis vintages (95% CI 1.013–1.060, p = .002), higher concomitant diabetes rates (95% CI 1.375–10.374, p = .010), and lower (each 1-absolute unit decrease) Kt/V values (95% CI 0.859–0.984, p = .015) were independent risk factors for progression to sSHPT in patients on PD. During follow-up, 211 deaths occurred (sSHPT group, n = 35; non-sSHPT group, n = 176). The sSHPT group had significantly higher infection-related mortality rates than the non-sSHPT group (12.0% vs. 4.3%; p < .05), and sSHPT was associated with increased infection-related mortality. In conclusion, patients with sSHPT are at higher risk for death and infection-related mortality than patients without sSHPT.

#665 Comparison of outcomes between kidney transplant-naïve and post-transplant graft failure peritoneal dialysis patients

Abstract Background and Aims Despite progress in kidney transplant medicine, there are still patients experiencing graft failure and returning to dialysis therapy. Data regarding the prognosis of these patients remain conflicting. This study was conducted to compare clinical outcomes between transplant-naïve peritoneal dialysis (PD) patients and those returning to PD after a failed allograft. Method In this retrospective cohort study during 2006 and 2016, we included a total of 786 patients on chronic PD. Of them 679 were transplant-naïve, 76 patients underwent a successful transplantation, and 32 patients returned to PD after a failed kidney allograft. Baseline demographics and clinical characteristics were analyzed in relation to the outcomes of all-cause mortality and peritonitis rate. We employed the Kaplan-Meier method and Cox proportional hazards model to evaluate survival, while Poisson regression was utilized to estimate rate ratios for peritonitis. Results During a median follow-up of 6.37 years, 56.68 % death and 146.62 episodes of peritonitis/patient-year were observed. Compared with patients who received a kidney graft, transplant-naïve patients were older, more with diabetes and having higher mortality (58.6 ± 15.8, 40.5% and 57.73%, p &amp;lt; 0.0001). After accounting for age, gender, and comorbidities, the adjusted hazards ratios were 0.26 (95% CI 0.13-0.53) in patients with a functioning graft and 1.12 (95% CI 0.61-2.06) in patients returning to PD after graft failure, compared respectively with concurrent PD patients without kidney transplant. The adjusted relative risk of peritonitis in patients resuming PD after graft failure was comparable to those without kidney transplant (95% CI 0.22-1.14). Conclusion Successful kidney transplant reduced the risk of overall mortality among patients on long-term PD. Patients returning to PD after graft loss showed outcomes similar to transplant-naïve counterparts. These data support reactivation of PD as a viable option for patients with a failed kidney transplant.

Inhibition of STAT3 by S3I-201 suppress peritoneal fibroblast phenotype conversion and alleviate peritoneal fibrosis.

Peritoneal fibrosis is a common pathological response to long-term peritoneal dialysis (PD) and a major cause for PD discontinuation. Understanding the cellular and molecular mechanisms underlying the induction and progression of peritoneal fibrosis is of great interest. In our study, invitro study revealed that signal transducer and activator of transcription 3 (STAT3) is a key factor in fibroblast activation and extracellular matrix (ECM) synthesis. Furthermore, STAT3 induced by IL-6 trans-signalling pathway mediate the fibroblasts of the peritoneal stroma contributed to peritoneal fibrosis. Inhibition of STAT3 exerts an antifibrotic effect by attenuating fibroblast activation and ECM production with an invitro co-culture model. Moreover, STAT3 plays an important role in the peritoneal fibrosis in an animal model of peritoneal fibrosis developed in mice. Blocking STAT3 can reduce the peritoneal morphological changes induced by chlorhexidine gluconate. In conclusion, our findings suggested STAT3 signalling played an important role in peritoneal fibrosis. Therefore, blocking STAT3 might become a potential treatment strategy in peritoneal fibrosis.

Serum Lipoprotein(a) Levels as a Predictor of Aortic Stiffness in Patients on Long-Term Peritoneal Dialysis

Serum Lipoprotein(a) Levels as a Predictor of Aortic Stiffness in Patients on Long-Term Peritoneal Dialysis

Role of endothelial hyaluronan in peritoneal membrane transport and disease conditions during peritoneal dialysis

Peritoneal membrane dysfunction in peritoneal dialysis (PD) is primarily attributed to angiogenesis; however, the integrity of vascular endothelial cells can affect peritoneal permeability. Hyaluronan, a component of the endothelial glycocalyx, is reportedly involved in preventing proteinuria in the normal glomerulus. One hypothesis suggests that development of encapsulating peritoneal sclerosis (EPS) is triggered by protein leakage due to vascular endothelial injury. We therefore investigated the effect of hyaluronan in the glycocalyx on peritoneal permeability and disease conditions. After hyaluronidase-mediated degradation of hyaluronan on the endothelial cells of mice, macromolecules, including albumin and β2 microglobulin, leaked into the dialysate. However, peritoneal transport of small solute molecules was not affected. Pathologically, hyaluronan expression was diminished; however, expression of vascular endothelial cadherin and heparan sulfate, a core protein of the glycocalyx, was preserved. Hyaluronan expression on endothelial cells was studied using 254 human peritoneal membrane samples. Hyaluronan expression decreased in patients undergoing long-term PD treatment and EPS patients treated with conventional solutions. Furthermore, the extent of hyaluronan loss correlated with the severity of vasculopathy. Hyaluronan on endothelial cells is involved in the peritoneal transport of macromolecules. Treatment strategies that preserve hyaluronan in the glycocalyx could prevent the leakage of macromolecules and subsequent related complications.

A time-averaged serum bicarbonate-based nomogram to predict the probability of residual kidney function preservation for patients undergoing peritoneal dialysis.

Residual kidney function (RKF) is an important prognostic indicator in peritoneal dialysis (PD) patients. So far, there are no prediction tools available for RKF, and the association between serum bicarbonate and RKF has received little attention in patients with PD. We aimed to develop a nomogram for the preservation of RKF based on the time-averaged serum bicarbonate (TA-Bic) levels. A prediction model was established by conducting a retrospective cohort study of 151 PD patients who had been treated at the First Affiliated Hospital of Anhui Medical University. The nomogram was developed using a multivariate Cox regression model. The discrimination, calibration, and clinical utility of the model were evaluated by the C-index, receiver operating curve (ROC) curve, calibration curve, and decision curve analysis. In the elderly PD onset, higher baseline values of residual glomerular filtration rate, total Kt/V and higher TA-Bic levels were identified as protective predictors of RKF loss. The nomogram was conducted on the basis of the minimum value of the Akaike Information Criterion and Bayesian Information Criterion with a reasonable C-index of 0.766, showing great discrimination, proper calibration, and high potential for clinical practice. Through the total score of the nomogram, the patients were classified into the high-risk group and low-risk group, and a higher cumulative incidence of complete RRF loss was found in the high-risk group compared with the patients in the low-risk group. The novel predictive nomogram model can predict the probability of RKF preservation in long-term PD patients with high accuracy. Future studies are needed to externally validate the current nomogram before clinical application.

Intercellular communication in peritoneal dialysis.

Long-term peritoneal dialysis (PD) causes structural and functional alterations of the peritoneal membrane. Peritoneal deterioration and fibrosis are multicellular and multimolecular processes. Under stimulation by deleterious factors such as non-biocompatibility of PD solution, various cells in the abdominal cavity show differing characteristics, such as the secretion of different cytokines, varying protein expression levels, and transdifferentiation into other cells. In this review, we discuss the role of various cells in the abdominal cavity and their interactions in the pathogenesis of PD. An in-depth understanding of intercellular communication and inter-organ communication in PD will lead to a better understanding of the pathogenesis of this disease, enabling the development of novel therapeutic targets.

Unravelling the role of Sildenafil and SB204741 in suppressing fibrotic potential of peritoneal fibroblasts obtained from PD patients.

Introduction: Peritoneal fibrosis (PF) results in technique failure in peritoneal dialysis (PD) patients. Peritoneal fibroblasts are characterized by increase in the ACTA2 gene, responsible for alpha smooth muscle actin (α-SΜΑ), extracellular matrix (ECM) production, and inflammatory cytokines production, which are the are key mediators in the pathogenesis of PF. 5-hydroxytryptamine (5-HT; serotonin) induces ECM synthesis in fibroblasts in a transforming growth factor-beta 1 (TGF-β1) dependent manner. The purpose of our study was to identify the potential mechanism and role of sildenafil and 5HT2B receptor inhibitor (SB204741) combination in attenuating PD-associated peritoneal fibrosis. Methods: Studies were performed to determine the effect of TGF-β1, sildenafil, and SB204741 on human peritoneal fibroblasts (HPFBs) isolated from the parietal peritoneum of patients in long-term PD patients (n = 6) and controls (n = 6). HPFBs were incubated with TGF-β1 (10ng/mL) for 1h and later with TGF-β1 (10ng/mL)/[sildenafil (10µM) or SB204741 (1µM)] and their combination for 24h (post-treatment strategy). In the pre-treatment strategy, HPFBs were pre-treated with sildenafil (10µM) or SB204741 (1µM) and a combination of the two for 1h and later with only TGF-β1 (10ng/mL) for 24h. Results: The anti-fibrotic effects of the combination of sildenafil and SB204741 were greater than that of each drug alone. In TGF-β1-stimulated HPFBs, pro-fibrotic genes (COL1A1, COL1A2, ACTA2, CTGF, FN1, and TGFB1) exhibited higher expression than in controls, which are crucial targets of sildenafil and SB204741 against peritoneal fibrosis. The synergistic approach played an anti-fibrotic role by regulating the pro- and anti-fibrotic gene responses as well as inflammatory cytokine responses. The combination treatment significantly attenuated peritoneal fibrosis, as evident by the almost complete amelioration of ACTA2 expression, restoration of anti-fibrotic genes (MMP2/TIMP1), and, at least, by reducing the expression of pro-inflammatory cytokines (IFN-γ, IL-4, IL-17, IL-1β, IL-6, TNF-α, and TGF-β1) along with an increase in IL-10 levels. Discussion: Taken together, the above research evidences that the combination of sildenafil and SB204741 may have therapeutic potential in suppressing peritoneal fibrosis due to peritoneal dialysis.

A protective role of nintedanib in peritoneal fibrosis through H19-EZH2-KLF2 axis via impeding mesothelial-to-mesenchymal transition.

Peritoneal fibrosis (PF), a common complication of long-term peritoneal dialysis, accounts for peritoneal ultrafiltration failure to develop into increased mortality. Nintedanib has previously been shown to protect against multi-organ fibrosis, including PF. Unfortunately, the precise molecular mechanism underlying nintedanib in the pathogenesis of PF remains elusive. The mouse model of PF was generated by chlorhexidine gluconate (CG) injection with or without nintedanib administration, either with the simulation for the cell model of PF by constructing high-glucose (HG)-treated human peritoneal mesothelial cells (HPMCs). HE and Masson staining were applied to assess the histopathological changes of peritoneum and collagen deposition. FISH, RT-qPCR, western blot and immunofluorescence were employed to examine distribution or expression of targeted genes. Cell viability was detected using CCK-8 assay. Cell morphology was observed under a microscope. RNA immunoprecipitation (RIP) and chromatin immunoprecipitation (ChIP) assays were applied to validate the H19-EZH2-KLF2 regulatory axis. Aberrantly overexpressed H19 was observed in both the mouse and cell model of PF, of which knockdown significantly blocked HG-induced mesothelial-to-mesenchymal transition (MMT) of HPMCs. Moreover, loss of H19 further strengthened nintedanib-mediated suppressive effects against MMT process in a mouse model of PF. Mechanistically, H19 could epigenetically repressed KLF2 via recruiting EZH2. Furthermore, TGF-β/Smad pathway was inactivated by nintedanib through mediating H19/KLF2 axis. In summary, nintedanib disrupts MMT process through regulating H19/EZH2/KLF2 axis and TGF-β/Smad pathway, which laid the experimental foundation for nintedanib in the treatment of PF.

Clinical observation and influence on nutritional status of intensive nutritional nursing combined with 3-day dietary diary intervention in peritoneal dialysis patients.

Peritoneal dialysis is a commonly used treatment for chronic kidney failure patients. Studies have shown that long-term peritoneal dialysis can lead to various degrees of malnutrition. Therefore, it is of great significance to improve the nutritional conditions of patients with peritoneal dialysis. This retrospective cohort study aimed to evaluate the clinical effects of intensive nutritional nursing combined with a 3-day diet diary intervention on the nutritional condition of peritoneal dialysis patients. In total, 163 patients were included in this study and, after 6 months of intervention, their nutritional and biochemical indicators, body weight, body mass index (BMI) and intake of dietary ingredients were analysed. After the intervention, patients' serum albumin, haemoglobin, prealbumin, body weight, BMI and cholesterol levels were significantly increased (p < 0.05). Also, the daily energy and protein intake were significantly increased, whereas phosphorus intake was decreased (p < 0.05). Of note, the effective rate of intervention was 63.8%, respectively. We also found that factors such as the patient's age, education degree, income level and peritoneal dialysis age were the risk factors associated with malnutrition. Moreover, patients younger than 55 years old, with dialysis age younger than 5 years, unmarried/divorced and high school graduates, had higher chances of effective intervention, whereas the possibility of effective intervention was lower when the per capita monthly household income was less than 4000 Yuan. In conclusion, intensive nutritional nursing combined with a 3-day dietary diary intervention can significantly improve the nutritional condition and optimise the diet structure of peritoneal dialysis patients with malnutrition. These findings provide evidence for healthcare providers to develop personalised interventions to address malnutrition in this population.

Melatonin inhibits the formation of chemically induced experimental encapsulating peritoneal sclerosis through modulation of T cell differentiation by suppressing of NF-κB activation in dendritic cells

Encapsulating peritoneal sclerosis (EPS) is a severe complication of peritoneal dialysis (PD). Surgery is a therapeutic strategy for the treatment of complete intestinal obstruction. However, complete intestinal obstruction in long-term PD results in high mortality and morbidity rates after surgery. Immunopathogenesis participates in EPS formation: CD8, Th1, and Th17 cell numbers increased during the formation of EPS. The anti-inflammatory and immunomodulatory effects of melatonin may have beneficial effects on this EPS. In the present study, we determined that melatonin treatment significantly decreases the Th1 and Th17 cell populations in mice with EPS, decreases the production of IL-1β, TNF-α, IL-6, and IFN-γ, and increases the production of IL-10. The suppression of Th1 and Th17 cell differentiation by melatonin occurs through the inhibition of dendritic cell (DC) activation by affecting the initiation of the NF-κB signaling pathway in DCs. Our study suggests that melatonin has preventive potential against the formation of EPS in patients with PD.

Identification of Genes Associated with Decreasing Abundance of Monocytes in Long-Term Peritoneal Dialysis Patients.

Chronic kidney disease (CKD) will become an end-stage renal disease (ESRD) at stage 5. Peritoneal dialysis (PD) is required for renal replacement therapy. This study aims to identify monocytes-related genes in peritoneal cells from long-term PD (LPD) patients and short-term PD (SPD) patients. Bulk RNA-seq data (GSE125498 dataset) and ScRNA-seq data (GSE130888) were downloaded to identify differentially expressed genes, monocytes-related genes, and monocytes marker genes in LPD patients. Immune infiltration was analyzed in the GSE125498 dataset. Core genes associated with monocytes changes were screened out, followed by functional analysis and expression validation using RT-PCR. Monocytes are the most abundant immune cell in PD. The number of monocytes was remarkably decreased in LPD compared with SPD. A total of 16 up-regulated core genes negatively correlated with the abundance of monocytes were obtained in LPD. The expression of 16 core genes was lower in monocyte clusters than that in other cell clusters. In addition, LCK, CD3G, CD3E, CD3D, and LAT were involved in the signaling pathways of Th1 and Th2 cell differentiation, T cell receptor signaling pathway, and Th17 cell differentiation. CD2 was involved in hematopoietic cell lineage signaling pathway. Identification of monocytes related-genes and related signaling pathways could be helpful in understanding the molecular mechanism of monocytes changes during PD.

Clinical risk factors for peritoneal dialysis withdrawal at different dialysis duration

Background The duration of patients maintained on peritoneal dialysis (PD) varied. This study investigated the clinical risk factors for PD withdrawal at different dialysis duration. Methods Patients who initiated PD from 1994 to 2011 were recruited and followed for at least 10 years until 2021. Patients were grouped into four groups according to dialysis duration or time on treatment (TOT) when withdrew PD. Results A cohort of 586 patients were enrolled (mean age of 54.9 years, median dialysis duration or TOT of 47.9 months). Patients who maintained PD for longer than 10 years were younger, with lower prevalence of diabetes, lower serum C-reactive protein (CRP) level and white blood cell (WBC) count, higher serum albumin and pre-albumin level, higher normalized protein catabolic rate (nPCR) and residual kidney function, and more common use of renin–angiotensin system inhibitors (RASi) at baseline (p < 0.05 for all). Peritonitis related death and ultrafiltration failure related HD transferring increased along with time on PD (p < 0.001). Old age, diabetes, low serum albumin, high WBC count, hypertensive nephropathy, and nonuse of RASi were associated with increased risk of non-transplantation related PD withdrawal (p < 0.05 for all). Low baseline CRP and use of RASi were independent predictors for long-term PD maintenance (p < 0.05 for all). Conclusions Long-term PD patients demonstrated young age, low prevalence of diabetes, better nutrition status, absence of inflammation, better residual kidney function, and higher proportion of RASi usage at baseline. Absence of inflammation and use of RASi were independently associated with long-term PD maintenance.

Advanced Image-Guided Percutaneous Technique Versus Advanced Laparoscopic Surgical Technique for Peritoneal Dialysis Catheter Placement

Timely placement of a functional peritoneal dialysis (PD) catheter is crucial to long-term PD success. Advanced image-guided percutaneous and advanced laparoscopic techniques both represent best practice catheter placement options. Advanced image-guided percutaneous is a minimally invasive procedure that does not require general anesthesia. Retrospective cohort study comparing time from referral to procedure, complication rate, and 1-year catheter survival between placement techniques. Patients who had advanced laparoscopic or advanced image-guided percutaneous PD catheter placement from January 1, 2011 to December 31, 2013 in an integrated Northern California health care delivery system. PD catheter placement using advanced laparoscopic or advanced image-guided percutaneous techniques. One-year PD catheter survival; major, minor, and infectious complications; time from referral to PD catheter placement; and procedure time. Wilcoxon rank sum tests to compare referral and procedure times; χ2/Fisher exact tests to compare complications; and modified least-squares regression to compare adjusted 1-year catheter survival between PD placement techniques. We identified 191 and 238 PD catheters placed through advanced image-guided percutaneous and advanced laparoscopic techniques, respectively. Adjusted 1-year PD catheter survival was 80% (95% CI, 74%-87%) using advanced image-guided percutaneous technique vs 91% (87%-96%) using advanced laparoscopic technique (P=0.01). Major complications were<1% in both groups. Minor and infectious complications were 45.6% and 38.7% in advanced image-guided percutaneous and advanced laparoscopic techniques, respectively (P=0.01). Median days from referral to procedure were 12 and 33 for patients undergoing advanced image-guided percutaneous and advanced laparoscopic techniques, respectively (P<0.001). Median procedure time was 30 and 44.5 minutes for patients undergoing advanced image-guided percutaneous and advanced laparoscopic techniques, respectively (P<0.001). Retrospective study with practice preference influenced by timing, local expertise, and resources. Both advanced image-guided percutaneous and advanced laparoscopic techniques reported rare major complications and demonstrated excellent (advanced laparoscopic) and acceptable (advanced image-guided percutaneous) 1-year PD catheter survival. For patients referred for PD catheter placement at centers where advanced laparoscopic resources or expertise remain limited, the advanced image-guided percutaneous technique can provide a complementary and timely option to support the utilization of PD. Peritoneal dialysis is a preferred dialysis modality for many patients. However, the lack of available skilled surgeons can limit the placement of the peritoneal dialysis catheter in a timely manner. In the past decade, interventional radiology has developed expertise in placing peritoneal dialysis catheters. Using data from an integrated health care system, we compared the outcome of peritoneal dialysis catheters placed using laparoscopic surgery and interventional radiology techniques. Our results showed excellent 1-year patency of peritoneal dialysis catheters placed using laparoscopic surgery, whereas interventional radiology placement of catheters had lower but acceptable1-year patency survival, based on best practice guideline criteria. Hence, interventional radiology placement of peritoneal dialysis catheters may be a viable alternative when laparoscopic surgery is not available or feasible.

Magnesium inhibits peritoneal calcification as a late-stage characteristic of encapsulating peritoneal sclerosis

Peritoneal calcification is a prominent feature of the later stage of encapsulating peritoneal sclerosis (EPS) in patients undergoing long-term peritoneal dialysis (PD). However, the pathogenesis and preventive strategy for peritoneal calcification remain unclear. Peritoneum samples from EPS patients were examined histologically. Peritoneal calcification was induced in mice by feeding with an adenine-containing diet combined with intraperitoneal administration of lipopolysaccharide and a calcifying solution containing high calcium and phosphate. Excised mouse peritoneum, human mesothelial cells (MeT5A), and mouse embryonic fibroblasts (MEFs) were cultured in calcifying medium. Immunohistochemistry confirmed the appearance of osteoblastic differentiation-marker-positive cells in the visceral peritoneum from EPS patients. Intraperitoneal administration of magnesium suppressed peritoneal fibrosis and calcification in mice. Calcifying medium increased the calcification of cultured mouse peritoneum, which was prevented by magnesium. Calcification of the extracellular matrix was accelerated in Met5A cells and MEFs treated with calcification medium. Calcifying medium also upregulated osteoblastic differentiation markers in MeT5A cells and induced apoptosis in MEFs. Conversely, magnesium supplementation mitigated extracellular matrix calcification and phenotypic transdifferentiation and apoptosis caused by calcifying conditions in cultured MeT5A cells and MEFs. Phosphate loading contributes to the progression of EPS through peritoneal calcification and fibrosis, which can be prevented by magnesium supplementation.

Glucose-induced pseudohypoxia and advanced glycosylation end products explain peritoneal damage in long-term peritoneal dialysis.

Long-term peritoneal dialysis is associated with the development of peritoneal membrane alterations, both in morphology and function. Impaired ultrafiltration (UF) is the most important functional change, and peritoneal fibrosis is the major morphological alteration. Both are caused by the continuous exposure to dialysis solutions that are different from plasma water with regard to the buffer substance and the extremely high-glucose concentrations. Glucose has been incriminated as the major cause of long-term peritoneal membrane changes, but the precise mechanism has not been identified. We argue that glucose causes the membrane alterations by peritoneal pseudohypoxia and by the formation of advanced glycosylation end products (AGEs). After a summary of UF kinetics including the role of glucose transporters (GLUT), and a discussion on morphologic alterations, relationships between function and morphology and a survey of the pathogenesis of UF failure (UFF), it will be argued that impaired UF is partly caused by a reduction in small pore fluid transport as a consequence of AGE-related vasculopathy and - more importantly - in diminished free water transport due to pseudohypoxia, caused by increased peritoneal cellular expression of GLUT-1. The metabolism of intracellular glucose will be reviewed. This occurs in the glycolysis and in the polyol/sorbitol pathway, the latter is activated in case of a large supply. In both pathways the ratio between the reduced and oxidised form of nicotinamide dinucleotide (NADH/NAD+ ratio) will increase, especially because normal compensatory mechanisms may be impaired, and activate expression of hypoxia-inducible factor-1 (HIF-1). The latter gene activates various profibrotic factors and GLUT-1. Besides replacement of glucose as an osmotic agent, medical treatment/prevention is currently limited to tamoxifen and possibly Renin/angiotensis/aldosteron (RAA) inhibitors.

Complement terminal pathway inhibition reduces peritoneal injuries in a rat peritonitis model.

Peritonitis and the resulting peritoneal injuries are common problems that prevent long-term peritoneal dialysis (PD) therapy in patients with end-stage kidney diseases. Previously, we have analyzed the relationship between the complement system and progression of peritoneal injuries associated with PD, particularly focusing on the early activation pathways and effects of the anaphylatoxins. We here utilized a novel mAb 2H2 that blocks assembly of the membrane attack complex (MAC) to investigate roles of the complement terminal pathway in PD-associated peritoneal injury. We intraperitoneally injected mAb 2H2 anti-C5b-7 (2.5 or 5 mg/rat) once or twice over the five-day course of the experiment to investigate the effects of inhibiting formation of MAC in a fungal rat peritonitis model caused by repeated intraperitoneal administration of zymosan after methylglyoxal pretreatment (Zy/MGO model). Rats were sacrificed on day 5 and macroscopic changes in both parietal and visceral peritoneum evaluated. Peritoneal thickness, the abundance of fibrinogen and complement C3 and MAC deposition in tissue and accumulation of inflammatory cells were pathologically assessed. The results showed that mAb 2H2, but not isotype control mAb, reduced peritoneal thickness and accumulation of inflammatory cells in a dose and frequency-dependent manner in the Zy/MGO model. These effects were accompanied by decreased C3, MAC, and fibrinogen deposition in peritoneum. In conclusion, in the rat Zy/MGO model, complement terminal pathway activation and MAC formation substantially contributed to development of peritoneal injuries, suggesting that MAC-targeted therapies might be effective in preventing development of peritoneal injuries in humans.

Pleuroperitoneal communication-associated pleuritis as an uncommon cause of fever of unknown origin in a child on peritoneal dialysis: a case report

Pleuroperitoneal communication (PPC) is a rare mechanical complication of peritoneal dialysis (PD), which causes dialysate to move from the peritoneal cavity to the pleural cavity, resulting in pleural effusion. Typically, PPC is discovered through pleural effusion in PD patients who are not in volume overload status. A unique characteristic of the pleural effusion caused by PPC is that it is not resolved by increasing ultrafiltration by dialysis. In this report, we present a 7-year-old girl with PD after birth with the history of various infectious PD-related complications, presenting with fever ongoing for 6 months. PPC-associated pleuritis was suspected as the cause of fever, which eventually developed after long-term PD and induced complicated pleural effusion, lung inflammation, and prolonged fever for 6 months.

Extracellular vesicle-packaged ILK from mesothelial cells promotes fibroblast activation in peritoneal fibrosis.

Progressive peritoneal fibrosis and the loss of peritoneal function often emerged in patients undergoing long-term peritoneal dialysis (PD), resulting in PD therapy failure. Varieties of cell-cell communications among peritoneal cells play a significant role in peritoneal fibrogenesis. Extracellular vesicles (EVs) have been confirmed to involve in intercellular communication by transmitting proteins, nucleic acids or lipids. However, their roles and functional mechanisms in peritoneal fibrosis remain to be determined. Using integrative analysis of EV proteomics and single-cell RNA sequencing, we characterized the EVs isolated from PD patient's effluent and revealed that mesothelial cells are the main source of EVs in PD effluent. We demonstrated that transforming growth factor-β1 (TGF-β1) can substitute for PD fluid to stimulate mesothelial cells releasing EVs, which in turn promoted fibroblast activation and peritoneal fibrogenesis. Blockade of EVs secretion by GW4869 or Rab27a knockdown markedly suppressed PD-induced fibroblast activation and peritoneal fibrosis. Mechanistically, injured mesothelial cells produced EVs containing high level of integrin-linked kinase (ILK), which was delivered to fibroblast and activated them via p38 MAPK signalling pathway. Clinically, the expression of ILK was up-regulated in fibrotic peritoneum of patients undergoing long-term PD. The percentage of ILK positive EVs in PD effluent correlated with peritoneal dysfunction and the degree of peritoneal damage. Our study highlights that peritoneal EVs mediate communications between mesothelial cells and fibroblasts to initiate peritoneal fibrogenesis. Targeting EVs or ILK could provide a novel therapeutic strategy to combat peritoneal fibrosis.

Granuloma formation after repeated episodes of peritoneal dialysis catheter–related infection, a case report

BackgroundPeritoneal catheter related infection is one of the main complications and the major cause of technical failure of peritoneal dialysis (PD) treatment. However, PD catheter tunnel infection can be difficult to diagnosis and resolve. We presented a rare case in which a granuloma formation after repeated episodes of peritoneal dialysis catheter–related infection.Case presentationA 53-year-old female patient with kidney failure due to chronic glomerulonephritis treated with peritoneal dialysis for 7 years. The patient had repeated exit-site and tunnel inflammation, and repeated suboptimal courses of antibiotics. She switched to hemodialysis after 6 years in a local hospital without the peritoneal dialysis catheter being removed. The patient complained of an abdominal wall mass that lasted for several months. She was admitted to the Department of surgery to undergo mass resection. The resected tissue of the abdominal wall mass was sent for pathological examination. The result showed foreign body granuloma with necrosis and abscess formation. After the surgery, the infection did not recur.ConclusionsThe following key points can be learned from this case: 1. It is important to strengthen patient follow-up. 2.The PD catheter should be removed as early as possible in patients who do not need long-term PD, especially in patients with a history of exit-site and tunnel infections. 3. For patients presenting abnormal subcutaneous mass, attention should be paid to the possibility of the granuloma formation of infected Dacron cuffs of the PD catheter. If catheter infection occurs repeatedly, catheter removal and debridement should be considered.