New developments in peritoneal fibroblast biology: implications for inflammation and fibrosis in peritoneal dialysis

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.

Transcriptomic analysis identifies novel candidates in cardiorenal pathology mediated by chronic peritoneal dialysis

Peritoneal dialysis (PD) is associated with increased cardiovascular (CV) risk. Studies of PD-related CV pathology in animal models are lacking despite the clinical importance. Here we introduce the phenotypic evaluation of a rat model of cardiorenal syndrome in response to chronic PD, complemented by a rich transcriptomic dataset detailing chronic PD-induced changes in left ventricle (LV) and kidney tissues. This study aims to determine how PD alters CV parameters and risk factors while identifying pathways for potential therapeutic targets. Sprague Dawley rats underwent Sham or 5/6 nephrectomy (5/6Nx) at 10 weeks of age. Six weeks later an abdominal dialysis catheter was placed in all rats before random assignment to Control or PD (3 daily 1-h exchanges) groups for 8 days. Renal and LV pathology and transcriptomic analysis was performed. The PD regimen reduced circulating levels of BUN in 5/6Nx, indicating dialysis efficacy. PD did not alter blood pressure or cardiovascular function in Sham or 5/6Nx rats, though it attenuated cardiac hypertrophy. Importantly PD increased serum triglycerides in 5/6Nx rats. Furthermore, transcriptomic analysis revealed that PD induced numerous changed transcripts involved with inflammatory pathways, including neutrophil activation and atherosclerosis signaling. We have adapted a uremic rat model of chronic PD. Chronic PD induced transcriptomic changes related to inflammatory signaling that occur independent of 5/6Nx and augmented circulating triglycerides and predicted atherosclerosis signaling in 5/6Nx LV tissues. The changes are indicative of increased CV risk due to PD and highlight several pathways for potential therapeutic targets.

Novel Aspects of the Immune Response Involved in the Peritoneal Damage in Chronic Kidney Disease Patients under Dialysis

Chronic kidney disease (CKD) incidence is growing worldwide, with a significant percentage of CKD patients reaching end-stage renal disease (ESRD) and requiring kidney replacement therapies (KRT). Peritoneal dialysis (PD) is a convenient KRT presenting benefices as home therapy. In PD patients, the peritoneum is chronically exposed to PD fluids containing supraphysiologic concentrations of glucose or other osmotic agents, leading to the activation of cellular and molecular processes of damage, including inflammation and fibrosis. Importantly, peritonitis episodes enhance peritoneum inflammation status and accelerate peritoneal injury. Here, we review the role of immune cells in the damage of the peritoneal membrane (PM) by repeated exposure to PD fluids during KRT as well as by bacterial or viral infections. We also discuss the anti-inflammatory properties of current clinical treatments of CKD patients in KRT and their potential effect on preserving PM integrity. Finally, given the current importance of coronavirus disease 2019 (COVID-19) disease, we also analyze here the implications of this disease in CKD and KRT.

İntrabdominal Adezyon Oluşum Mekanizmalarına ve Tedavi Stratejilerine Histopatolojik Bakış

Hayat standartlarını olumsuz etkileyen abdominal adezyonlar, postoperatif dönemde görülen önemli bir sağlık sorunudur. Peritoneal kavite ve serozal yüzeylerde oluşan, abdominal travmalara sebep olan kimyasal ve termal faktörler ya da enfeksiyon ve yabancı cisim reaksiyonları adezyon oluşumuna sebep olabilir. Abdominal adezyonların sınıflandırması genellikle adezyon yoğunluğuna ve prognoz ciddiyetine göre yapılsa da henüz dünya çapında kabul görmüş standart bir sınıflandırma sistemi mevcut değildir. Abdominal adezyonlar ağrı, infertilite, cerrahi sonrası hastanede yatış süresinin uzaması ve ekonomik yük gibi olumsuz sonuçlarla klinik yansımalar gösterir. Sonuç olarak, postoperatif süreçte karşılaşılan adezyonlar ciddi bir sorundur ve adezyon oluşumunu engellemek için ileri çalışmaların laboratuvar ortamından klinik araştırma modellerine uyarlanması gerekmektedir. Bu derleme çalışması intraabdominal adezyon oluşumu, histopatolojisi, derecelendirilmesi, önlenmesi ve klinik önemi ile ilgili literatürü gözden geçirmek için hazırlanmıştır.

Meropenem antibiotic therapy in acute secondary peritonitis, therapeutic effects superior to other therapies - experimental clinical and histopathological study in the laboratory animal

AIM

A perforated peptic ulcer is the most common cause of peritonitis through the perforation of the digestive tube, which occurs in a percentage between 2% and 14% of patients diagnosed with peptic ulcer and being associated with a 10% to 30% mortality rate.

MATERIALS AND METHODS

Considering the above, we imagined a study, using laboratory animals, in which we produced gastric perforations, then followed their evolution without antibiotic treatment and under antibiotic therapy with Cefuroxime 25 mg∕kg∕24 hours intravenously or Meropenem 40 mg∕kg∕24 hours intravenously, following the tissue changes both macroscopically and microscopically.

RESULTS

The study revealed a mortality of 36.6%, most deaths (81.82%) occurred in the first 24 hours after the perforation, all subjects belonging to the group that did not receive antibiotic treatment and the group treated with Cefuroxime. From a clinical point of view (evaluation of the general condition), macroscopically and microscopically, a better evolution of the subjects who received antibiotic therapy can be observed, compared to those who did not receive antibiotic therapy, thus in the case of subjects who received antibiotic therapy, the absence or the presence of a small amount of intraperitoneal fluid, which has a serocitrine appearance, as well as the absence of macroscopic changes at the level of unaffected intraperitoneal organs, can be observed. Microscopically, it can be seen that in the subjects treated with Meropenem, changes in the parietal peritoneum were minimal.

CONCLUSIONS

Antibiotic therapy with Meropenem in acute peritonitis has a survival rate comparable to peritoneal lavage and source control.

Gut microbial metabolite TMAO increases peritoneal inflammation and peritonitis risk in peritoneal dialysis patients

Trimethylamine-N-oxide (TMAO), a gut microbiota-produced metabolite, is accumulated in chronic kidney disease (CKD) patients. It is well known to contribute to CKD-related cardiovascular complications. However, the effect of TMAO on peritoneal dialysis (PD)-related peritonitis remains largely unknown. Here, we demonstrate that serum concentrations of TMAO were positively correlated with C-reactive protein levels, and the appearance rate of dialysate IL-6 and PAI-1, in PD patients. During the follow-up period of 28.3 ± 8.0 months, patients with higher TMAO levels (≥50 μM) had a higher risk of new-onset peritonitis (HR, 3.60; 95%CI, 1.18-10.99; P=0.025) after adjusting for sex, age, diabetes, PD duration, BUN, rGFR, C-reactive protein, BMI and β2-M. In CKD rat models, TMAO significantly promoted peritoneal dialysate-induced inflammatory cell infiltration, inflammatory cytokines production in the peritoneum. In vitro study revealed that TMAO directly induced primary peritoneal mesothelial cell necrosis, together with increased production of pro-inflammatory cytokines including CCL2, TNF-α, IL-6, and IL-1β. In addition, TMAO significantly increased TNF-α-induced P-selectin production in mesothelial cells, as well as high glucose-induced TNF-α and CCL2 expression in endothelial cells. In conclusion, our data demonstrate that higher levels of TMAO exacerbate peritoneal inflammation and might be a risk factor of incidence of peritonitis in PD patients.

Strategies for extended lifetime of implantable intraperitoneal insulin catheters

Implantable insulin infusion systems using the intra-peritoneal route have dramatically changed the management of diabetes paving the way toward the realization of the potential "holy grail" of a fully implantable artificial pancreas. However, the wear duration of delivery catheters is compromised by the foreign body-mediated immune response. Both occlusion material present at the distal catheter tip end and fibrotic encapsulation surrounding the catheters influence the controlled and precise delivery of insulin, which eventually leads to the need for surgical intervention. The novel part of the current work is the investigation of the roles of implant physical properties (catheter size and tip configuration), as well as local inflammation control (through utilization of an anti-inflammatory agent) on the host fibrotic response using a previously developed animal model. The cellular and molecular response, the medication delivery efficacy as well as the ability to flush the catheters were examined and further compared among the different mitigation strategies. Reduction in catheter size as well as tuning the tip configuration from a cone shape to a round shape showed delayed host recognition and delayed propagation of the fibrotic response. However, the round shaped tips had an increased occurrence of lumen occlusion as a result of flow change. It became apparent that changing the physical properties of the catheters was not a long-term solution to catheter obstructions caused by the foreign body reaction. In comparison, control of the local inflammatory response through the use of an anti-inflammatory agent demonstrated a promising strategy for maintenance of catheter functionality without any type of obstructions. These finding will have a large impact toward the development of long-term use catheters for continuous intraperitoneal insulin infusion.

Increased expression of epimorphin in a peritoneal fibrosis mouse model

BACKGROUND

Long-term peritoneal dialysis results in functional and histopathological alterations of the peritoneal membrane, leading to peritoneal fibrosis (PF). The mechanism of PF has not been fully elucidated, and at present there is no effective therapy for PF. Epimorphin is a mesenchymal protein that not only regulates morphogenesis in organ development but is implicated in tissue repair. However, the role of epimorphin in PF has not yet been clarified.

METHODS

PF was induced in C57/Bl6 mice by intraperitoneal injection of chlorhexidine gluconate (CG-injected mice) three times a week for 3 weeks. The parietal peritoneum was subsequently dissected and assessed by Masson's trichrome staining, and epimorphin expression was analysed by immunohistochemistry and real-time reverse transcription polymerase chain reaction (RT-PCR). Furthermore, epimorphin-positive regions were analysed by multiple immunofluorescence staining using fibrosis-associated markers. In addition, normal rat fibroblast cells (NRK-49F) were treated with transforming growth factor-β (TGF-β) in the presence or absence of epimorphin. The expression of fibrosis-associated markers was assessed by real-time RT-PCR.

RESULTS

In CG-injected mice, Masson's trichrome staining showed marked thickening of the submesothelial compact zone. Weak epimorphin expression was observed in the narrow submesothelial compact zone beneath the mesothelial cells in control mice; however, epimorphin expression was stronger in the submesothelial compact zone in CG-injected mice. Epimorphin expression was observed mainly in α-smooth muscle actin (α-SMA)-positive myofibroblasts. Epimorphin suppressed the TGF-β-induced upregulation of α-SMA and platelet-derived growth factor receptor-β in cultured cells.

CONCLUSIONS

Our results suggest that epimorphin may be a therapeutic target for fibrotic diseases of the peritoneum.

Immunoregulation by type I interferons in the peritoneal cavity

The peritoneal cavity, a fluid-containing potential space surrounding the abdominal and pelvic organs, is home to a rich network of immune cells that maintain tissue homeostasis and provide protection against infection. However, under pathological conditions such as peritonitis, endometriosis, and peritoneal carcinomatosis, the peritoneal immune system can become dysregulated, resulting in nonresolving inflammation and disease progression. An enhanced understanding of the factors that regulate peritoneal immune cells under both homeostatic conditions and in disease contexts is therefore required to identify new treatment strategies for these often life-limiting peritoneal pathologies. Type I interferons (T1IFNs) are a family of cytokines with broad immunoregulatory functions, which provide defense against viruses, bacteria, and cancer. There have been numerous reports of immunoregulation by T1IFNs within the peritoneal cavity, which can contribute to both the resolution or propagation of peritoneal disease states, depending on the specifics of the disease setting and local environment. In this review, we provide an overview of the major immune cell populations that reside in the peritoneal cavity (or infiltrate it under inflammatory conditions) and highlight their contribution to the initiation, progression, or resolution of peritoneal diseases. Additionally, we will discuss the role of T1IFNs in the regulation of peritoneal immune cells, and summarize the results of laboratory studies and clinical trials which have investigated T1IFNs in peritonitis/sepsis, endometriosis, and peritoneal carcinomatosis.

Root cause determination of intraperitoneal catheter obstructions: Insulin amyloid aggregates vs foreign body reaction

Continuous intraperitoneal insulin infusion, from an implanted insulin pump connected to a catheter that delivers insulin directly to the peritoneal cavity has many clinical advantages for patients with Type 1 diabetes. However, the ongoing incidence of catheter obstructions remains a barrier to the widespread use of this therapy. To date, the root cause of these obstructions remains unknown. Here, a two-year clinical investigation was conducted, along with the development of an animal model to enable a mechanistic investigation into this issue. This novel animal model was able to mimic the catheter obstructions that occur in patients and, fortuitously, at an accelerated rate. This model allowed for independent assessment of each potential cause associated with catheter obstructions to help identify the root cause. Both macroscopic and microscopic analysis were conducted with regards to the onset and progression of catheter obstructions, along with monitoring of insulin delivery. Interestingly, although insulin aggregation occurs in insulin pumps and insulin aggregates were found in some catheter obstructions, insulin is unlikely to be the root cause, since obstructions also occurred in the control groups where only diluent (no insulin) was administered to the animals. Inflammatory cells, different phenotypes of fibroblasts, as well as collagen were observed in all obstructed catheters explanted from the patients and the animals. The presence of these cells and collagen is indicative of a typical foreign body reaction. In addition, the dynamic change in the fibroblasts with respect to morphology, phenotype, and spatial distribution suggests that tissue irritation-mediated epithelial to mesenchymal transition plays a role in catheter obstructions.

Mechanisms of Peritoneal Fibrosis: Focus on Immune Cells-Peritoneal Stroma Interactions

Peritoneal fibrosis is characterized by abnormal production of extracellular matrix proteins leading to progressive thickening of the submesothelial compact zone of the peritoneal membrane. This process may be caused by a number of insults including pathological conditions linked to clinical practice, such as peritoneal dialysis, abdominal surgery, hemoperitoneum, and infectious peritonitis. All these events may cause acute/chronic inflammation and injury to the peritoneal membrane, which undergoes progressive fibrosis, angiogenesis, and vasculopathy. Among the cellular processes implicated in these peritoneal alterations is the generation of myofibroblasts from mesothelial cells and other cellular sources that are central in the induction of fibrosis and in the subsequent functional deterioration of the peritoneal membrane. Myofibroblast generation and activity is actually integrated in a complex network of extracellular signals generated by the various cellular types, including leukocytes, stably residing or recirculating along the peritoneal membrane. Here, the main extracellular factors and the cellular players are described with emphasis on the cross-talk between immune system and cells of the peritoneal stroma. The understanding of cellular and molecular mechanisms underlying fibrosis of the peritoneal membrane has both a basic and a translational relevance, since it may be useful for setup of therapies aimed at counteracting the deterioration as well as restoring the homeostasis of the peritoneal membrane.

Single-cell transcriptomics provides new insights into the role of fibroblasts during peritoneal fibrosis

BACKGROUND

The contributions of various types of cell populations in dialysis-related peritoneal fibrosis are poorly understood. Single-cell RNA sequencing brings single-cell level resolution to the analysis of cellular transcriptomics, which provides a new way to further characterize the distinct roles and functional states of each cell population during peritoneal fibrosis.

METHODS

Single-cell transcriptomics from normal peritoneal tissues of six patients, from effluent of patients with short-term peritoneal dialysis (less than 2 weeks, n = 6), and from long-term peritoneal dialysis patients (more than 6 years, n = 4) were analyzed.

RESULTS

We identified a distinct cell component between samples among different groups. Functional analysis of the differentially expressed genes identified cell type specific biological processes relevant to different fibrosis stages. Well-known key molecular mechanisms participating in the pathophysiology of peritoneal fibrosis were vitrified, and some of them were found to be restricted to specific cell types. Gradually growing enrichment of PI3K/AKT/mTOR pathway and impairment of oxidative phosphorylation in mesothelial cells and fibroblasts were found from healthy control, short-term dialysis, to long-term dialysis, respectively. The fibroblasts' population obtained from the patients, who received peritoneal dialysis, showed a functional characteristic of immune-chemotaxis and immune response, which was characterized by broadly significant increase in the expression of interleukins, chemokines, cytokines, and human leukocyte antigens. Furthermore, we described the intercellular crosstalk networks based on receptor-ligand interactions, and highlighted a central role of fibroblasts in regulating the key mechanisms of peritoneal fibrosis through crosstalk with other cells.

CONCLUSIONS

In summary, despite describing information for fibrogenic molecular mechanisms in the resolution level of individual cell populations, this work identifies the significant functional evolution of fibroblasts during peritoneal fibrosis. This study also reveals the intercellular receptor-ligand interactions in which the fibroblasts serve as a major node, eventually providing new insights into the role of fibroblasts during disease pathogenesis.

The calcium concentration of peritoneal dialysis solution modifies levels of key mediators of peritoneal fibrosis

BACKGROUND

To explore the effects of different calcium concentrations of peritoneal dialysis solution (PDS) on continuous ambulatory peritoneal dialysis (CAPD) and expression of vimentin (VIM), fibroblast-specific protein (FSP1), and E-cadherin.

MATERIALS AND METHODS

This was a pilot study (#ChiCTR1900021387) conducted from January 2017 to December 2019 at the Hospital. The patients were randomized to undergo CAPD using PDS with a calcium concentration of 1.25 mmol/L (low concentration group) or 1.75 mmol/L (high concentration group). Changes in biochemistry before dialysis and at 6 and 12 months were analyzed.

RESULTS

There were 50 and 52 participants in the low and high calcium groups. The blood biochemical indexes were all different between the two groups (all Ptime  < .05, Pgroup  < .05, Pinteraction  < .05), but they remained within their normal ranges. VIM and FSP1 increased over 12 months (Ptime  < .05); VIM and FSP1 levels in the high concentration group were higher than in the low concentration group (Pgroup  < .05, Pinteraction  < .05), while E-cadherin showed the inverse association (Ptime  < .001, Pgroup  < .001, Pinteraction  < .001). There was no difference in complications (P = .973).

CONCLUSION

The calcium concentration in PDS might be an important factor affecting the progression of peritoneal fibrosis.

Inhibition of hyperglycolysis in mesothelial cells prevents peritoneal fibrosis

Progressive peritoneal fibrosis affects patients receiving peritoneal dialysis (PD) and has no reliable treatment. The mechanisms that initiate and sustain peritoneal fibrosis remain incompletely elucidated. To overcome these problems, we developed a strategy that prevents peritoneal fibrosis by suppressing PD-stimulated mesothelial-to-mesenchymal transition (MMT). We evaluated single-cell transcriptomes of mesothelial cells obtained from normal peritoneal biopsy and effluent from PD-treated patients. In cells undergoing MMT, we found cellular heterogeneity and intermediate transition states associated with up-regulation of enzymes involved in glycolysis. The expression of glycolytic enzymes was correlated with the development of MMT. Using gene expression profiling and metabolomics analyses, we confirmed that PD fluid induces metabolic reprogramming, characterized as hyperglycolysis, in mouse peritoneum. We found that transforming growth factor β1 (TGF-β1) can substitute for PD fluid to stimulate hyperglycolysis, suppressing mitochondrial respiration in mesothelial cells. Blockade of hyperglycolysis with 2-deoxyglucose (2-DG) inhibited TGF-β1-induced profibrotic cellular phenotype and peritoneal fibrosis in mice. We developed a triad of adeno-associated viruses that overexpressed microRNA-26a and microRNA-200a while inhibiting microRNA-21a to target hyperglycolysis and fibrotic signaling. Intraperitoneal injection of the viral triad inhibited the development of peritoneal fibrosis induced by PD fluid in mice. We conclude that hyperglycolysis is responsible for MMT and peritoneal fibrogenesis, and this aberrant metabolic state can be corrected by modulating microRNAs in the peritoneum. These results could provide a therapeutic strategy to combat peritoneal fibrosis.

Therapeutic effect of 1,25(OH)2-VitaminD3 on fibrosis and angiogenesis of peritoneum induced by chlorhexidine

The biological activity of vitamin D, which mediated by the vitamin D receptor, is widespread throughout the body. The present study aimed to define whether 1,25-dihydroxy vitamin D3 (1,25-(OH)2D3) can protect against the progression of peritoneum fibrosis (PF) through its impact on the expression of connective tissue growth factor (CTGF) and heat shock protein 47 (HSP47) in vivo and in vitro. The male Sprague-Dawley (SD) rats of PF were induced by daily intraperitoneally injection of chlorhexidine gluconate (CG) for 4 wks. PF Rats were also treated with calcitriol (i.p. 6 ng/100g*d) from initiation of the CG. In calcitriol rats, the ultrafiltration and the ratio of dialysate urea nitrogen to blood urea nitrogen were improved (P < 0.05), pathological changes and peritoneal thickness were milder than that of the PF group. Calcitriol ameliorated high glucose-induced HSP47 expression in peritoneal mesothelial cells via CTGF down-regulation both at the mRNA level and protein level. Furthermore, calcitriol prevented angiogenic mediators of fibrosis by reduced the expression of CD34 and vascular endothelial growth factor (VEGF). The present study demonstrated that 1,25-(OH)2D3 intervention had a partially protective effect on peritoneum fibrosis, which might inhibit CTGF/HSP47 and CD34/VEGF in the peritoneum tissues.

An Optimized Method to Isolate Human Fibroblasts from Tissue for ex vivo Analysis

Despite their involvement in many physiological and pathological processes, fibroblasts remain a poorly-characterized cell type. Analysis of primary fibroblasts while maintaining their in vivo phenotype is challenging: standard methods for fibroblast isolation require cell culture in vitro, which is known to alter phenotypes. Previously-described protocols for the dissociation of primary tissues fail to extract sufficient numbers of fibroblasts, instead largely yielding immune cells. Here, we describe an optimized method for generating a fibroblast-enriched single-cell suspension from human tissues using combined mechanical and enzymatic dissociation. This allows analysis of ex vivo fibroblasts without the need for culture in vitro.

Effect of astragaloside IV and the role of nuclear receptor RXRα in human peritoneal mesothelial cells in high glucose‑based peritoneal dialysis fluids

Peritoneal fibrosis is a serious complication that can occur during peritoneal dialysis (PD), which is primarily caused by damage to peritoneal mesothelial cells (PMCs). The onset of peritoneal fibrosis is delayed or inhibited by promoting PMC survival and inhibiting PMC epithelial-to-mesenchymal transition (EMT). In the present study, the effect of astragaloside IV and the role of the nuclear receptor retinoid X receptor-α (RXRα) in PMCs in high glucose-based PD fluids was investigated. Human PMC HMrSV5 cells were transfected with RXRα short hairpin RNA (shRNA), or an empty vector, and then treated with PD fluids and astragaloside IV. Cell viability, apoptosis and EMT were examined using the Cell Counting Kit-8 assay and flow cytometry, and by determining the levels of caspase-3, E-cadherin and α-smooth muscle actin (α-SMA) via western blot analysis. Cell viability and apoptosis were increased, as were the levels of E-cadherin in HMrSV5 cells following treatment with PD fluid. The protein levels of α-SMA and caspase-3 were increased by treatment with PD fluid. Exposure to astragaloside IV inhibited these changes; however, astragaloside IV did not change cell viability, apoptosis, E-cadherin or α-SMA levels in HMrSV5 cells under normal conditions. Transfection of HMrSV5 cells with RXRα shRNA resulted in decreased viability and E-cadherin expression, and increased apoptosis and α-SMA levels, in HMrSV5 cells treated with PD fluids and co-treated with astragaloside IV or vehicle. These results suggested that astragaloside IV increased cell viability, and inhibited apoptosis and EMT in PMCs in PD fluids, but did not affect these properties of PMCs under normal condition. Thus, the present study suggested that RXRα is involved in maintaining viability, inhibiting apoptosis and reducing EMT of PMCs in PD fluid.

Role of Different Blood Purification Nursing Models in Uremic Patients: A Preliminary Report

Background

Accumulation of uremic toxins is closely associated with chronic kidney disease (CKD)-related complications such as cerebrovascular accidents and cardiovascular diseases. Clinical nursing is accepted as a critical clinical prognosis factor for hospitalized patients. The present study was designed to compare the effects of different blood purification nursing models on clinical outcomes in patients with uremia.

Material/Methods

A total of 68 patients with uremia were selected and divided to control and intervention groups. The patients in the control group received traditional nursing model care, while the patients in intervention group received comprehensive high-quality nursing care for 6 months.

Results

After 6 months of treatment, the quality of life, anxiety, and depression were obviously ameliorated in both groups. The levels of blood urea nitrogen (BUN), parathyroid hormone (PTH), creatinine, β2-microglobulin (β2-MG), total cholesterol (TC), albumin (ALB), interleukin-1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α), C-reactive protein (CRP), 8-isoprostane, and malondialdehyde (MDA), as well as superoxide dismutase (SOD) and catalase (CAT) activities were all significantly improved in both groups of patients, but the intervention group exhibited better results than the control group.

Conclusions

Our results demonstrated that comprehensive high-quality nursing care rectified the metabolic disorders and inhibited systematic inflammatory factors, and oxidative stress, which may be responsible for better amelioration of quality of life in patients with uremia.

Pre-therapy CT scan showing peritoneal thickening from metastatic renal pelvis carcinoma patients

We investigated clinical significance of peritoneal thickening from metastatic renal pelvis based on pretherapy computed tomography (CT) scan findings. The criteria for inclusion were as follows: (1) pathology and CT scan confirmed metastatic renal pelvis carcinoma and (2) peritoneal thickening based on pre-therapy CT scan findings. We investigated the route of spread, gastrointestinal (GI) complications, and response to chemotherapy. A total of 68 cases were enrolled in this study, including seven patients with liver metastases and three with abdominal wall invasion. GI complications included obstruction in ten patients and bleeding in three. Response to chemotherapy demonstrated by reduced peritoneal thickening was noted in 24 patients. In conclusion. peritoneal thickening with clinical suspicion of peritoneal involvement can get indirect evidence from route of spread (liver or abdominal wall), GI complications (obstruction or bleeding) or response to chemotherapy (obvious decrease peritoneal thickening) from metastatic renal pelvis carcinoma patients. Pretherapy CT scan with peritoneal thickening should be alert that tumor has spread to the peritoneum.

The peritoneum: healing, immunity, and diseases

The peritoneum defines a confined microenvironment, which is stable under normal conditions, but is exposed to the damaging effect of infections, surgical injuries, and other neoplastic and non-neoplastic events. Its response to damage includes the recruitment, proliferation, and activation of a variety of haematopoietic and stromal cells. In physiological conditions, effective responses to injuries are organized; inflammatory triggers are eliminated; inflammation quickly abates; and the normal tissue architecture is restored. However, if inflammatory triggers are not cleared, fibrosis or scarring occurs and impaired tissue function ultimately leads to organ failure. Autoimmune serositis is characterized by the persistence of self-antigens and a relapsing clinical pattern. Peritoneal carcinomatosis and endometriosis are characterized by the persistence of cancer cells or ectopic endometrial cells in the peritoneal cavity. Some of the molecular signals orchestrating the recruitment of inflammatory cells in the peritoneum have been identified in the last few years. Alternative activation of peritoneal macrophages was shown to guide angiogenesis and fibrosis, and could represent a novel target for molecular intervention. This review summarizes current knowledge of the alterations to the immune response in the peritoneal environment, highlighting the ambiguous role played by persistently activated reparative macrophages in the pathogenesis of common human diseases. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Biomarker research to improve clinical outcomes of peritoneal dialysis: consensus of the European Training and Research in Peritoneal Dialysis (EuTRiPD) network

Peritoneal dialysis (PD) therapy substantially requires biomarkers as tools to identify patients who are at the highest risk for PD-related complications and to guide personalized interventions that may improve clinical outcome in the individual patient. In this consensus article, members of the European Training and Research in Peritoneal Dialysis Network (EuTRiPD) review the current status of biomarker research in PD and suggest a selection of biomarkers that can be relevant to the care of PD patients and that are directly accessible in PD effluents. Currently used biomarkers such as interleukin-6, interleukin-8, ex vivo-stimulated interleukin-6 release, cancer antigen-125, and advanced oxidation protein products that were collected through a Delphi procedure were first triaged for inclusion as surrogate endpoints in a clinical trial. Next, novel biomarkers were selected as promising candidates for proof-of-concept studies and were differentiated into inflammation signatures (including interleukin-17, M₁/M₂ macrophages, and regulatory T cell/T helper 17), mesothelial-to-mesenchymal transition signatures (including microRNA-21 and microRNA-31), and signatures for senescence and inadequate cellular stress responses. Finally, the need for defining pathogen-specific immune fingerprints and phenotype-associated molecular signatures utilizing effluents from the clinical cohorts of PD patients and "omics" technologies and bioinformatics-biostatistics in future joint-research efforts was expressed. Biomarker research in PD offers the potential to develop valuable tools for improving patient management. However, for all biomarkers discussed in this consensus article, the association of biological rationales with relevant clinical outcomes remains to be rigorously validated in adequately powered, prospective, independent clinical studies.

Active compounds extracted from extra virgin olive oil counteract mesothelial-to-mesenchymal transition of peritoneal mesothelium cells exposed to conventional peritoneal dialysate: in vitro and in vivo evidences

During peritoneal dialysis (PD), peritoneal mesothelial cells undergo a transition from an epithelial phenotype to a mesenchymal phenotype that, together with the inflammatory process, promotes tissue fibrosis and a failure of peritoneal membrane function. To date, there is no definitive treatment for the progressive thickening and angiogenesis of the peritoneal membrane associated with PD. In this study we tested, in vitro and in vivo, the ability of active compounds extracted from extra virgin olive oil (AC-EVOO) to counteract the mesothelial-to-mesenchymal transition process (MMT) observed in mesothelial cells chronically exposed to the conventional peritoneal dialysate (DL). In particular, we used a cultivar from southern Italy known to have a high polyphenol content. Our results showed that, in mesothelial cells exposed to DL, the combined treatment with AC-EVOO prevented the genic and protein upregulation of key mesenchymal and inflammatory markers, as well as the MCs' migratory capacity. Concomitantly, we tested the antifibrotic efficacy of AC-EVOO in mesothelial cells obtained from effluents of patients undergoing PD, whose "fibroblast-like" phenotype was defined by flow-cytometry assay. We observed that in these cells AC-EVOO significantly mitigated, but did not reverse, the MMT process. In conclusion, our preliminary results suggest that AC-EVOO can interfere with critical factors in the process of differentiation, preventing myofibroblast formation, but once fibrosis has already progressed it is unable to promote the redifferentiation to the epithelial phenotype. Further studies are needed to establish whether AC-EVOO could represent a new therapeutic target to prevent peritoneal fibrosis.

Clinical study of Shengxuening tablet combined with rHuEPO for the treatment of renal anemia of maintenance hemodialysis patients

The aim of the present study was to investigate the clinical effects of Shengxuening tablet (silkworm excrement) combined with recombinant human erythropoietin (rHuEPO) for the treatment of renal anemia of maintenance hemodialysis (MHD) patients. Seventy-two MHD patients with renal anemia were included in the study and randomly divided into the control (n=34) and observation (n=38) groups. Patients in the control group were treated by hypodermic injection of 100-150 U/(kg·w) rHuEPO and patients in the observation group were treated by rHuEPO + 1.0 g t.i.d. p.o. Shengxuening tablet. The two groups were assisted by conventional treatments including iron, folic acid, vitamin B12 and L-carnitine. After 3 and 6 months, improvement of anemia was compared. After 3 months, the hemoglobin, hematocrit, serum ferritin and transferrin saturation levels of the observation group were significantly higher than those of the control group (p<0.05). In addition, C-reactive protein and superoxide dismutase levels of the observation group were significantly lower than those of the control group (p<0.05). After 6 months, indices of the observation group were ameliorated while the improvement of control group was not obvious, and indices of the observation group were significantly higher than those of the control group (p<0.05). Consumption of rHuEPO in the observation group was significantly less than that of the control group, and the total effective rate was significantly higher than that of the control group (p<0.05). In conclusion, Shengxuening tablet combined with rHuEPO was safe and effective for the treatment of renal anemia of MHD patients.