Astragalus membranaceus and its monomers treat peritoneal fibrosis and related muscle atrophy through the AR/TGF-ß1 pathway.

Background: To anticipate the potential molecular mechanism of Astragalus membranaceus (AM) and its monomer, Calycosin, against peritoneal fibrosis (PF) and related muscle atrophy using mRNA-seq, network pharmacology, and serum pharmacochemistry. Methods: Animal tissues were examined to evaluate a CKD-PF mice model construction. mRNA sequencing was performed to find differential targets. The core target genes of AM against PF were screened through network pharmacology analysis, and CKD-PF mice models were given high- and low-dose AM to verify common genes. Serum pharmacochemistry was conducted to clarify which components of AM can enter the blood circulation, and the selected monomer was further validated through cell experiments for the effect on PF and mesothelial mesenchymal transition (MMT) of peritoneal mesothelial cells (PMCs). Results: The CKD-PF mice models were successfully constructed. A total of 31,184 genes were detected in the blank and CKD-PF groups, and 228 transcription factors had significant differences between the groups. Combined with network pharmacology analysis, a total of 228 AM-PF-related targets were identified. Androgen receptor (AR) was the remarkable transcription factor involved in regulating transforming growth factor-ß1 (TGF-ß1). AM may be involved in regulating the AR/TGF-ß1 signaling pathway and may alleviate peritoneal dialysis-related fibrosis and muscle atrophy in CKD-PF mice. In 3% peritoneal dialysis solution-stimulated HMrSV5 cells, AR expression levels were dramatically reduced, whereas TGF-ß1/p-smads expression levels were considerably increased. Conclusion: AM could ameliorate PF and related muscle atrophy via the co-target AR and modulated AR/TGF-ß1 pathway. Calycosin, a monomer of AM, could partially reverse PMC MMT via the AR/TGF-ß1/smads pathway. This study explored the traditional Chinese medicine theory of "same treatment for different diseases," and supplied the pharmacological evidence of "AM can treat flaccidity syndrome."

LCZ696, an angiotensin receptor-neprilysin inhibitor, ameliorates epithelial-mesenchymal transition of peritoneal mesothelial cells and M2 macrophage polarization.

AIMS: To investigate the effects and mechanisms of LCZ696, an angiotensin receptor-neprilysin inhibitor (ARNI), on epithelial-mesenchymal transition (EMT) of peritoneal mesothelial cells and on macrophage M2 polarization. METHODS: We examined the effects of LCZ696 in a 4.25% high glucose peritoneal dialysis fluid (PDF)-induced peritoneal fibrosis (PF) mouse model, and explored the mechanisms of LCZ696 on human peritoneal mesothelial cells (HPMCs) stimulated by TGF-ß1 (5 ng/mL) and on Raw264.7 cells stimulated by IL-4 (10 ng/mL). To further elucidate the mechanism, we treated HPMCs with the conditioned medium of Raw264.7 cells. RESULTS: LCZ696 effectively improved PF and inhibited the process of EMT in PDF mice. In vitro, LCZ696 also significantly alleviated the EMT of TGF-ß1 induced HPMCs, although there was no statistically significant difference when compared to the Valsartan treatment group. Moreover, LCZ696 ameliorates the increased expression of Snail and Slug, two nuclear transcription factors that drive the EMT. Mechanistically, TGF-ß1 increased the expression of TGFßRI, p-Smad3, p-PDGFRß and p-EGFR, while treatment with LCZ696 abrogated the activation of TGF-ß/Smad3, PDGFRß and EGFR signaling pathways. Additionally, exposure of Raw264.7 to IL-4 results in increasing expression of Arginase-1, CD163 and p-STAT6. Treatment with LCZ696 inhibited IL-4-elicited M2 macrophage polarization by inactivating the STAT6 signaling pathway. Furthermore, we observed that LCZ696 inhibits EMT by blocking TGF-ß1 secretion from M2 macrophages. CONCLUSION: Our study demonstrated that LCZ696 improves PF and ameliorates TGF-ß1-induced EMT of HPMCs by blocking TGF-ß/Smad3, PDGFRß and EGFR pathways. Meanwhile, LCZ696 also inhibits M2 macrophage polarization by regulating STAT6 pathway.

MiR-454-3p regulates high glucose-induced mesothelial-mesenchymal transition and glycolysis in peritoneal mesothelial cells by targeting STAT3.

BACKGROUND: The quality of life of patients receiving long-term peritoneal dialysis (PD) is significantly impacted by the onset of peritoneal fibrosis (PF), and one of the pathological changes is mesothelial-mesenchymal transition (MMT). In this study, we investigated the potential roles of miR-454-3p and signal transducer and activator of transcription 3 (STAT3) in the progression of peritoneal MMT and the underlying mechanisms. METHODS: Peritoneums were collected to detect morphology via hematoxylin-eosin staining and differentially expressed miRNAs were detected via RT-qPCR. PD effluent-derived cell populations in the peritoneal cavity were isolated from the effluents of 20 PD patients to determine miR-454-3p, STAT3, and MMT markers via Western blotting and RT-qPCR. The relationship between miR-454-3p and STAT3 was examined via a dual-luciferase reporter assay. Western blotting and RT-qPCR were utilized to evaluate the expression of STAT3, MMT markers, and glycolytic enzymes. Immunofluorescence staining revealed the localization and expression of MMT markers and STAT3. RESULTS: MiR-454-3p was downregulated in the peritoneums and PD effluent-derived cell populations of long-term PD patients. High glucose (HG) treatment promoted HMrSV5 cell MMT and glycolysis. MiR-454-3p overexpression alleviated HG-induced MMT and suppressed the expression of STAT3 and glycolytic enzymes. In contrast, the miR-454-3p inhibitor exacerbated HG-induced MMT and promoted the expression of glycolytic enzymes and STAT3. Moreover, STAT3 was the target of miR-454-3p. CONCLUSIONS: This study demonstrated the protective role of miR-454-3p in HG-induced MMT and glycolysis in HMrSv5 cells, suggesting that miR-454-3p may prevent MMT by suppressing glycolytic enzymes via the STAT3/PFKFB3 pathway in the HG environment.

Physiology of peritoneal dialysis; pathophysiology in long-term patients.

The microvascular wall of peritoneal tissues is the main barrier in solute and water transport in the initial phase of peritoneal dialysis (PD). Small solute transport is mainly by diffusion through inter-endothelial pores, as is hydrostatic fluid transport with dissolved solutes. Water is also transported through the intra-endothelial water channel aquaporin-1(AQP-1) by a glucose-induced crystalloid osmotic gradient (free water transport). In the current review the physiology of peritoneal transport will be discussed both during the first years of PD and after long-term treatment with emphasis on the peritoneal interstitial tissue and its role in free water transport. Attention will be paid to the role of glucose-induced pseudohypoxia causing both increased expression of fibrogenetic factors and of the glucose transporter GLUT-1. The former leads to peritoneal fibrosis, the latter to a reduced crystalloid osmotic gradient, explaining the decrease in free water transport as a cause of ultrafiltration failure. These phenomena strongly suggest that the extremely high dialysate glucose concentrations are the driving force of both morphologic and functional peritoneal alterations that may develop during long-term PD.

Pathophysiological Mechanisms of Peritoneal Fibrosis and Peritoneal Membrane Dysfunction in Peritoneal Dialysis.

The characteristic feature of chronic peritoneal damage in peritoneal dialysis (PD) is a decline in ultrafiltration capacity associated with pathological fibrosis and angiogenesis. The pathogenesis of peritoneal fibrosis is attributed to bioincompatible factors of PD fluid and peritonitis. Uremia is associated with peritoneal membrane inflammation that affects fibrosis, neoangiogenesis, and baseline peritoneal membrane function. Net ultrafiltration volume is affected by capillary surface area, vasculopathy, peritoneal fibrosis, and lymphangiogenesis. Many inflammatory cytokines induce fibrogenic growth factors, with crosstalk between macrophages and fibroblasts. Transforming growth factor (TGF)-ß and vascular endothelial growth factor (VEGF)-A are the key mediators of fibrosis and angiogenesis, respectively. Bioincompatible factors of PD fluid upregulate TGF-ß expression by mesothelial cells that contributes to the development of fibrosis. Angiogenesis and lymphangiogenesis can progress during fibrosis via TGF-ß-VEGF-A/C pathways. Complement activation occurs in fungal peritonitis and progresses insidiously during PD. Analyses of the human peritoneal membrane have clarified the mechanisms by which encapsulating peritoneal sclerosis develops. Different effects of dialysates on the peritoneal membrane were also recognized, particularly in terms of vascular damage. Understanding the pathophysiologies of the peritoneal membrane will lead to preservation of peritoneal membrane function and improvements in technical survival, mortality, and quality of life for PD patients.

Clinical and preclinical studies of mesenchymal stem cells to alleviate peritoneal fibrosis.

Peritoneal dialysis is an important part of end-stage kidney disease replacement therapy. However, prolonged peritoneal dialysis can result in peritoneal fibrosis and ultrafiltration failure, forcing patients to withdraw from peritoneal dialysis treatment. Therefore, there is an urgent need for some effective measures to alleviate the occurrence and progression of peritoneal fibrosis. Mesenchymal stem cells play a crucial role in immunomodulation and antifibrosis. Numerous studies have investigated the fact that mesenchymal stem cells can ameliorate peritoneal fibrosis mainly through the paracrine pathway. It has been discovered that mesenchymal stem cells participate in the improvement of peritoneal fibrosis involving the following signaling pathways: TGF-ß/Smad signaling pathway, AKT/FOXO signaling pathway, Wnt/ß-catenin signaling pathway, TLR/NF-κB signaling pathway. Additionally, in vitro experiments, mesenchymal stem cells have been shown to decrease mesothelial cell death and promote proliferation. In animal models, mesenchymal stem cells can enhance peritoneal function by reducing inflammation, neovascularization, and peritoneal thickness. Mesenchymal stem cell therapy has been demonstrated in clinical trials to improve peritoneal function and reduce peritoneal fibrosis, thus improving the life quality of peritoneal dialysis patients.

Protective effect of Cyclo(His-Pro) on peritoneal fibrosis through regulation of HDAC3 expression.

Peritoneal dialysis is a common treatment for end-stage renal disease, but complications often force its discontinuation. Preventive treatments for peritoneal inflammation and fibrosis are currently lacking. Cyclo(His-Pro) (CHP), a naturally occurring cyclic dipeptide, has demonstrated protective effects in various fibrotic diseases, yet its potential role in peritoneal fibrosis (PF) remains uncertain. In a mouse model of induced PF, CHP was administered, and quantitative proteomic analysis using liquid chromatography-tandem mass spectrometry was employed to identify PF-related protein signaling pathways. The results were further validated using human primary cultured mesothelial cells. This analysis revealed the involvement of histone deacetylase 3 (HDAC3) in the PF signaling pathway. CHP administration effectively mitigated PF in both peritoneal tissue and human primary cultured mesothelial cells, concurrently regulating fibrosis-related markers and HDAC3 expression. Moreover, CHP enhanced the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) while suppressing forkhead box protein M1 (FOXM1), known to inhibit Nrf2 transcription through its interaction with HDAC3. CHP also displayed an impact on spleen myeloid-derived suppressor cells, suggesting an immunomodulatory effect. Notably, CHP improved mitochondrial function in peritoneal tissue, resulting in increased mitochondrial membrane potential and adenosine triphosphate production. This study suggests that CHP can significantly prevent PF in peritoneal dialysis patients by modulating HDAC3 expression and associated signaling pathways, reducing fibrosis and inflammation markers, and improving mitochondrial function.

Selective therapeutic efficacy of tyrosine kinase inhibitor sorafenib on the restoration of methylglyoxal-induced peritoneal fibrosis.

Peritoneal fibrosis, a common complication observed in long-term peritoneal dialysis patients, can gradually lead to ultrafiltration failure and the development of encapsulating peritoneal sclerosis. Although mechanisms of peritoneal fibrosis have been proposed, effective therapeutic options are unsatisfactory. Recently, several tyrosine kinase inhibitors have proven to be anti-fibrosis in rodent models. To assess the potential therapeutic effects of tyrosine kinase inhibitors on peritoneal fibrosis in the larger animal model, a novel porcine model of peritoneal fibrosis induced by 40 mM methylglyoxal in 2.5 % dialysate was established, and two different doses (20 mg/kg and 30 mg/kg) of sorafenib were given orally to evaluate their therapeutic efficacy in this study. Our results showed that sorafenib effectively reduced adhesions between peritoneal organs and significantly diminished the thickening of both the parietal and visceral peritoneum. Angiogenesis, vascular endothelial growth factor A production, myofibroblast infiltration, and decreased endothelial glycocalyx resulting from dialysate and methylglyoxal stimulations were also alleviated with sorafenib. However, therapeutic efficacy in ameliorating loss of mesothelial cells, restoring decreased ultrafiltration volume, and improving elevated small solutes transport rates was limited. In conclusion, this study demonstrated that sorafenib could potentially be used for peritoneal fibrosis treatment, but applying sorafenib alone might not be sufficient to fully rescue methylglyoxal-induced peritoneal defects.

Treatment of peritoneal fibrosis: Therapeutic prospects of bioactive Agents from Astragalus membranaceus.

Peritoneal dialysis is one of the renal replacement treatments for patients with end-stage renal disease. Peritoneal dialysis-related peritoneal fibrosis is a pathological change in peritoneal tissue of peritoneal dialysis patients with progressive, non-suppurative inflammation accompanied by fibrous tissue hyperplasia, resulting in damage to the original structure and function, leading to peritoneal function failure. Currently, there is no specific drug in the clinic. Therefore, it is necessary to find a drug with good effects and few adverse reactions. Astragalus membranaceus (AMS) is the dried root of the Astragalus membranaceus (Fisch.) Bge. AMS and its active ingredients play a significant role in anti-inflammation, anti-fibrosis, regulation of immune function and regulation of blood pressure. Studies have shown that it can alleviate peritoneal fibrosis by reducing inflammatory response, inhibiting oxidative stress, degrading extracellular matrix deposition, regulating apoptosis, and regulating Transforming Growth Factor-ß. The author summarized the relationship between AMS and its active ingredients by referring to relevant literature at home and abroad, in order to provide some theoretical basis for further clinical research.

Caffeic acid phenethyl ester restores mitochondrial homeostasis against peritoneal fibrosis induced by peritoneal dialysis through the AMPK/SIRT1 pathway.

Increasing evidence suggests that peritoneal fibrosis induced by peritoneal dialysis (PD) is linked to oxidative stress. However, there are currently no effective interventions for peritoneal fibrosis. In the present study, we explored whether adding caffeic acid phenethyl ester (CAPE) to peritoneal dialysis fluid (PDF) improved peritoneal fibrosis caused by PD and explored the molecular mechanism. We established a peritoneal fibrosis model in Sprague-Dawley rats through intraperitoneal injection of PDF and lipopolysaccharide (LPS). Rats in the PD group showed increased peritoneal thickness, submesothelial collagen deposition, and the expression of TGFß1 and α-SMA. Adding CAPE to PDF significantly inhibited PD-induced submesothelial thickening, reduced TGFß1 and α-SMA expression, alleviated peritoneal fibrosis, and improved the peritoneal ultrafiltration function. In vitro, peritoneal mesothelial cells (PMCs) treated with PDF showed inhibition of the AMPK/SIRT1 pathway, mitochondrial membrane potential depolarization, overproduction of mitochondrial reactive oxygen species (ROS), decreased ATP synthesis, and induction of mesothelial-mesenchymal transition (MMT). CAPE activated the AMPK/SIRT1 pathway, thereby inhibiting mitochondrial membrane potential depolarization, reducing mitochondrial ROS generation, and maintaining ATP synthesis. However, the beneficial effects of CAPE were counteracted by an AMPK inhibitor and siSIRT1. Our results suggest that CAPE maintains mitochondrial homeostasis by upregulating the AMPK/SIRT1 pathway, which alleviates oxidative stress and MMT, thereby mitigating the damage to the peritoneal structure and function caused by PD. These findings suggest that adding CAPE to PDF may prevent and treat peritoneal fibrosis.

The role of macrophage-derived Exosomes in reversing peritoneal fibrosis: Insights from Astragaloside IV.

BACKGROUND: Peritoneal dialysis (PD) is a successful renal replacement therapy for end-stage renal disease. Long-term PD causes mesothelial-mesenchymal transition (MMT) of peritoneal mesothelial cells (PMCs), leading to peritoneal fibrosis (PF), which reduces the efficiency of PD. Macrophages are thought to play a role in the onset and perpetuation of peritoneal injury. However, the mechanisms by which macrophages-PMCs communication regulates peritoneal fibrosis are not fully understood resulting in a lack of disease-modifying drugs. Astragaloside IV (AS-IV) possessed anti-fibrotic effect towards PF in PD whereas the mechanistic effect of AS-IV in PD is unknown. METHODS: The primary macrophages were extracted and treated with LPS or AS-IV, then co-cultured with primary PMCs in transwell plates. The macrophage-derived exosomes were extracted and purified by differential centrifugation, then co-cultured with primary PMCs. Small RNA-seq was used to detect differential miRNAs in exosomes, and then KEGG analysis and q-PCR were performed for validation. In vivo PD rat models were established by inducing with high-glucose peritoneal dialysis fluid and different concentrations of AS-IV and exosomes were intraperitoneal injection. Through qRT-PCR, western blotting, and luciferase reporting, candidate proteins and pathways were validated in vivo and in vitro. The functions of the validated pathways were further investigated using the mimic or inhibition strategy. PF and inflammatory situations were assessed. RESULTS: We found AS-IV reversed the MMT of PMCs caused by LPS-stimulated macrophages and the improving effect was mediated by macrophage-derived exosomes in vitro. We also demonstrated that AS-IV significantly reduced the MMT of PMCs in vitro or PF in a rat PD model via regulating exosome-contained miR-204-5p which targets Foxc1/ß-catenin signaling pathway. CONCLUSION: AS-IV attenuates macrophage-derived exosomes induced fibrosis in PD through the miR-204-5p/Foxc1 pathway.

Astragalus polysaccharides augment BMSC homing via SDF-1/CXCR4 modulation: a novel approach to counteract peritoneal mesenchymal transformation and fibrosis.

PURPOSE: This study aimed to evaluate the potential of astragalus polysaccharide (APS) pretreatment in enhancing the homing and anti-peritoneal fibrosis capabilities of bone marrow mesenchymal stromal cells (BMSCs) and to elucidate the underlying mechanisms. METHODS: Forty male Sprague-Dawley rats were allocated into four groups: control, peritoneal dialysis fluid (PDF), PDF + BMSCs, and PDF + APSBMSCs (APS-pre-treated BMSCs). A peritoneal fibrosis model was induced using PDF. Dil-labeled BMSCs were administered intravenously. Post-transplantation, BMSC homing to the peritoneum and pathological alterations were assessed. Stromal cell-derived factor-1 (SDF-1) levels were quantified via enzyme-linked immunosorbent assay (ELISA), while CXCR4 expression in BMSCs was determined using PCR and immunofluorescence. Additionally, a co-culture system involving BMSCs and peritoneal mesothelial cells (PMCs) was established using a Transwell setup to examine the in vitro effects of APS on BMSC migration and therapeutic efficacy, with the CXCR4 inhibitor AMD3100 deployed to dissect the role of the SDF-1/CXCR4 axis and its downstream impacts. RESULTS: In vivo and in vitro experiments confirmed that APS pre-treatment notably facilitated the targeted homing of BMSCs to the peritoneal tissue of PDF-treated rats, thereby amplifying their therapeutic impact. PDF exposure markedly increased SDF-1 levels in peritoneal and serum samples, which encouraged the migration of CXCR4-positive BMSCs. Inhibition of the SDF-1/CXCR4 axis through AMD3100 application diminished BMSC migration, consequently attenuating their therapeutic response to peritoneal mesenchyme-to-mesothelial transition (MMT). Furthermore, APS upregulated CXCR4 expression in BMSCs, intensified the activation of the SDF-1/CXCR4 axis's downstream pathways, and partially reversed the AMD3100-induced effects. CONCLUSION: APS augments the SDF-1/CXCR4 axis's downstream pathway activation by increasing CXCR4 expression in BMSCs. This action bolsters the targeted homing of BMSCs to the peritoneal tissue and amplifies their suppressive influence on MMT, thereby improving peritoneal fibrosis.

Untypical bilateral breast cancer with peritoneal fibrosis on 18F-FDG PET/CT: case report and literature review.

Background: Retroperitoneal fibrosis, a condition of uncertain origin, is rarely linked to 8% of malignant cases, including breast, lung, gastrointestinal, genitourinary, thyroid, and carcinoid. The mechanism leading to peritoneal fibrosis induced by tumors is not well understood, possibly encompassing direct infiltration of neoplastic cells or the initiation of inflammatory responses prompted by cytokines released by tumor cells. We report a case of breast cancer with renal metastasis and retroperitoneal fibrosis detected using 18F-FDG PET/CT, providing help for clinical diagnosis and treatment. Case report: A 49-year-old woman was referred to the hospital with elevated creatinine and oliguria for over a month. Abdominal computer tomography (CT) and magnetic resonance imaging (MRI) showed a retroperitoneal fibrosis-induced acute kidney injury (AKI) was suspected. However, a percutaneous biopsy of the kidney lesion confirmed metastasis from breast cancer. The physical examination revealed inverted nipples and an orange peel appearance on the skin of both breasts. Ultrasonography revealed bilateral hyperplasia (BIRADS 4a) of the mammary glands and bilateral neck and axillary lymphadenopathy. Subsequently, 18F-deoxyglucose positron emission tomography/computer tomography (18F-FDG PET/CT) detected abnormally high uptake (SUVmax) in the bilateral mammary glands and axillary lymph nodes, suggesting bilateral breast cancer. Furthermore, abnormal 18F-FDG uptake was detected in the kidney, suggesting renal metastasis. In addition, abnormal 18F-FDG uptake was observed in the vertebrae, accompanied by an elevation in inhomogeneous bone mineral density, raising suspicion of bone metastases. However, the possibility of myelodysplasia cannot be dismissed, and further investigations will be conducted during close follow-ups. There was significant 18F-FDG uptake in the retroperitoneal position indicating a potential association between retroperitoneal fibrosis and breast cancer. The final pathological diagnosis of the breast tissue confirmed bilateral invasive ductal carcinoma. The patient had been treated with 11 cycles of albumin-bound (nab)-paclitaxel (0.3 mg) and had no significant adverse reaction. Conclusion: In this case, neither the bilateral breast cancer nor the kidney metastatic lesion showed typical nodules or masses, so breast ultrasound, abdominal CT, and MRI did not suggest malignant lesions. PET/CT played an important role in detecting occult metastases and primary lesions, thereby contributing to more accurate staging, monitoring treatment responses, and prediction of prognosis in breast cancer.

BMSC-derived Exosomes Ameliorate Peritoneal Dialysis-associated Peritoneal Fibrosis via the Mir-27a-3p/TP53 Pathway.

OBJECTIVE: Peritoneal fibrosis (PF) is the main cause of declining efficiency and ultrafiltration failure of the peritoneum, which restricts the long-term application of peritoneal dialysis (PD). This study aimed to investigate the therapeutic effects and mechanisms of bone marrow mesenchymal stem cells-derived exosomes (BMSC-Exos) on PF in response to PD. METHODS: Small RNA sequencing analysis of BMSC-Exos was performed by second-generation sequencing. C57BL/6J mice were infused with 4.25% glucose-based peritoneal dialysis fluid (PDF) for 6 consecutive weeks to establish a PF model. A total of 36 mice were randomly divided into 6 groups: control group, 1.5% PDF group, 2.5% PDF group, 4.25% PDF group, BMSC-Exos treatment group, and BMSC-Exos+TP53 treatment group. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) was performed to measure the expression level of miR-27a-3p in BMSC-Exos and peritoneum of mice treated with different concentrations of PDF. HE and Masson staining were performed to evaluate the extent of PF. The therapeutic potential of BMSC-Exos for PF was examined through pathological examination, RT-qPCR, Western blotting, and peritoneal function analyses. Epithelial-mesenchymal transition (EMT) of HMrSV5 was induced with 4.25% PDF. Cells were divided into control group, 4.25% PDF group, BMSC-Exos treatment group, and BMSC-Exos+TP53 treatment group. Cell Counting Kit-8 assay was used to measure cell viability, and transwell migration assay was used to verify the capacity of BMSC-Exos to inhibit EMT in HMrSV5 cells. RESULTS: Small RNA sequencing analysis showed that miR-27a-3p was highly expressed in BMSC-derived exosomes compared to BMSCs. The RT-qPCR results showed that the expression of miR-27a-3p was upregulated in BMSC-Exos, but decreased in PD mice. We found that PF was glucose concentration-dependently enhanced in the peritoneum of the PD mice. Compared with the control mice, the PD mice showed high solute transport and decreased ultrafiltration volume as well as an obvious fibroproliferative response, with markedly increased peritoneal thickness and higher expression of α-SMA, collagen-I, fibronectin, and ECM1. The mice with PD showed decreased miR-27a-3p. Peritoneal structural and functional damage was significantly attenuated after BMSC-Exos treatment, while PF and mesothelial damage were significantly ameliorated. Additionally, markers of fibrosis (α-SMA, collagen-I, fibronectin, ECM1) and profibrotic cytokines (TGF-ß1, PDGF) were downregulated at the mRNA and protein levels after BMSC-Exos treatment. In HMrSV5 cells, BMSC-Exos reversed the decrease in cell viability and the increase in cell migratory capacity caused by high-glucose PDF. Western blotting and RT-qPCR analysis revealed that BMSC-Exos treatment resulted in increased expression of E-cadherin (epithelial marker) and decreased expression of α-SMA, Snail, and vimentin (mesenchymal markers) compared to those of the 4.25% PDF-treated cells. Importantly, a dual-luciferase reporter assay showed that TP53 was a target gene of miR-27a-3p. TP53 overexpression significantly reversed the decreases in PF and EMT progression induced by BMSC-Exos. CONCLUSION: The present results demonstrate that BMSC-Exos showed an obvious protective effect on PD-related PF and suggest that BMSC-derived exosomal miR-27a-3p may exert its inhibitory effect on PF and EMT progression by targeting TP53.

Abdominal cocoon syndrome-a rare culprit behind small bowel ischemia and obstruction: Three case reports.

BACKGROUND: Abdominal cocoon syndrome (ACS) represents a category within sclerosing encapsulating peritonitis, characterized by the encapsulation of internal organs with a fibrous, cocoon-like membrane of unknown origin, resulting in bowel obstruction and ischemia. Diagnosing this condition before surgery poses a challenge, often requiring confirmation during laparotomy. In this context, we depict three instances of ACS: One linked to intestinal obstruction, the second exclusively manifesting as intestinal ischemia without any obstruction, and the final case involving a discrepancy between the radiologist and the surgeon. CASE SUMMARY: Three male patients, aged 53, 58, and 61 originating from Northern Thailand, arrived at our medical facility complaining of abdominal pain without any prior surgeries. Their vital signs remained stable during the assessment. The diagnosis of abdominal cocoon was confirmed through abdominal computed tomography (CT) before surgery. In the first case, the CT scan revealed capsules around the small bowel loops, showing no enhancement, along with mesenteric congestion affecting both small and large bowel loops, without a clear obstruction. The second case showed intestinal obstruction due to an encapsulated capsule on the CT scan. In the final case, a patient presented with recurring abdominal pain. Initially, the radiologist suspected enteritis as the cause after the CT scan. However, a detailed review led the surgeon to suspect encapsulating peritoneal sclerosis (ACS) and subsequently perform surgery. The surgical procedure involved complete removal of the encapsulating structure, resection of a portion of the small bowel, and end-to-end anastomosis. No complications occurred during surgery, and the patients had a smooth recovery after surgery, eventually discharged in good health. The histopathological examination of the fibrous membrane (cocoon) across all cases consistently revealed the presence of fibro-collagenous tissue, without any indications of malignancy. CONCLUSION: Individuals diagnosed with abdominal cocoons commonly manifest vague symptoms of abdominal discomfort. An elevated degree of clinical suspicion, combined with the application of appropriate radiological evaluations, markedly improves the probability of identifying the abdominal cocoon before surgical intervention. In cases of complete bowel obstruction or ischemia, the established norm is the comprehensive removal of the peritoneal sac as part of standard care. Resection with intestinal anastomosis is advised solely when ischemia and gangrene have been confirmed.

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

Background: Encapsulating peritoneal sclerosis (EPS) is a rare complication of prolonged peritoneal dialysis (PD) exposure, characterised by peritoneal thickening, calcification, and fibrosis ultimately presenting with life-threatening bowel obstruction. The presence or role of peritoneal calcification in the pathogenesis of EPS is poorly characterised. We hypothesise that significantly aberrant bone mineral metabolism in patients on PD can cause peritoneal calcification which may trigger the development of EPS. We compared the temporal evolution of bone mineral markers during PD in EPS patients with non-EPS long-term PD controls. Methods: Linear mixed model and logistic regression analysis were used to compare four-monthly serum levels of calcium, phosphate, parathyroid hormone, and alkaline phosphatase (ALP) over the duration of PD exposure in 46 EPS and 46 controls (PD, non-EPS) patients. Results: EPS patients had higher mean calcium (2.51 vs. 2.41 mmol/L) and ALP (248.00 vs. 111.13 IU/L) levels compared with controls (p=0.01 and p<0.001 respectively, maximum likelihood estimation). Logistic regression analysis demonstrated that high serum calcium and phosphate levels during PD were associated with a 4.5 and 2.9 fold increase in the risk of developing EPS respectively. Conclusion: High levels of calcium and phosphate in patients on PD were identified to be risk factors for EPS development. Possible reasons for this may be an imbalance of pro-calcifying factors and calcification inhibitors promoting peritoneal calcification which increases peritoneal stiffness. Mechanical alterations may trigger, unregulated fibrosis and subsequent development of EPS. Improved management of secondary hyperparathyroidism during PD may ultimately diminish the EPS risk.

Expression and significance of SIRT6 in human peritoneal dialysis effluents and peritoneal mesothelial cells.

Sirtuin 6 (SIRT6) can inhibit the fibrosis of many organs. However, the relationship between SIRT6 and peritoneal fibrosis (PF) in peritoneal dialysis (PD) remains unclear. We collected 110 PD patients with a duration of PD for more than 3 months and studied the influence of PD duration and history of peritonitis on SIRT6 levels in PD effluents (PDEs). We also analyzed the relationship between SIRT6 levels in PDEs and transforming growth factor beta 1 (TGF-ß1), IL-6, PD duration, peritoneal function, PD ultrafiltration (UF), and glucose exposure. We extracted human peritoneal mesothelial cells (HPMCs) from PDEs and measured the protein and gene expression levels of SIRT6, E-cadherin, vimentin, and TGF-ß1 in these cells. Based on the clinical results, we used human peritoneal mesothelial cells lines (HMrSV5) to observe the changes in SIRT6 levels and mesothelial-to-mesenchymal transition (MMT) after intervention with PD fluid. By overexpressing and knocking down SIRT6 expression, we investigated the effect of SIRT6 expression on E-cadherin, vimentin, and TGF-ß1 expression to elucidate the role of SIRT6 in mesothelial-to-epithelial transition in PMCs. Results: (1) With the extension of PD duration, the influence of infection on SIRT6 levels in PDEs increased. Patients with the PD duration of more than 5 years and a history of peritonitis had the lowest SIRT6 levels. (2) SIRT6 levels in PDEs were negatively correlated with PD duration, total glucose exposure, TGF-ß1, IL-6 levels, and the dialysate-to-plasma ratio of creatinine (Cr4hD/P), but positively correlated with UF. This indicates that SIRT6 has a protective effect on the peritoneum. (3) The short-term group (PD ≤ 1 year) had higher SIRT6 and E-cadherin gene and protein levels than the mid-term group (1 year < PD ≤ 5 years) and long-term group (PD > 5 years) in PMCs, while vimentin and TGF-ß1 levels were lower in the mid-term group and long-term group. Patients with a history of peritonitis had lower SIRT6 and E-cadherin levels than those without such a history. (4) After 4.25% PD fluid intervention for HPMCs, longer intervention time resulted in lower SIRT6 levels. (5) Overexpressing SIRT6 can lead to increased E-cadherin expression and decreased vimentin and TGF-ß1 expression in HPMCs. Knocking down SIRT6 expression resulted in decreased E-cadherin expression and increased vimentin and TGF-ß1 expression in HPMCs. This indicates that SIRT6 expression can inhibit MMT in HPMCs, alleviate PF associated with PD, and have a protective effect on the peritoneum.

Integrative analysis of chromatin accessibility and transcriptome landscapes in the induction of peritoneal fibrosis by high glucose.

BACKGROUND: Peritoneal fibrosis is the prevailing complication induced by prolonged exposure to high glucose in patients undergoing peritoneal dialysis. METHODS: To elucidate the molecular mechanisms underlying this process, we conducted an integrated analysis of the transcriptome and chromatin accessibility profiles of human peritoneal mesothelial cells (HMrSV5) during high-glucose treatment. RESULTS: Our study identified 2775 differentially expressed genes (DEGs) related to high glucose-triggered pathological changes, including 1164 upregulated and 1611 downregulated genes. Genome-wide DEGs and network analysis revealed enrichment in the epithelial-mesenchymal transition (EMT), inflammatory response, hypoxia, and TGF-beta pathways. The enriched genes included VEGFA, HIF-1α, TGF-ß1, EGF, TWIST2, and SNAI2. Using ATAC-seq, we identified 942 hyper (higher ATAC-seq signal in high glucose-treated HMrSV5 cells than in control cells) and 714 hypo (lower ATAC-seq signal in high glucose-treated HMrSV5 cells versus control cells) peaks with differential accessibility in high glucose-treated HMrSV5 cells versus controls. These differentially accessible regions were positively correlated (R = 0.934) with the nearest DEGs. These genes were associated with 566 up- and 398 downregulated genes, including SNAI2, TGF-ß1, HIF-1α, FGF2, VEGFA, and VEGFC, which are involved in critical pathways identified by transcriptome analysis. Integrated ATAC-seq and RNA-seq analysis also revealed key transcription factors (TFs), such as HIF-1α, ARNTL, ELF1, SMAD3 and XBP1. Importantly, we demonstrated that HIF-1α is involved in the regulation of several key genes associated with EMT and the TGF-beta pathway. Notably, we predicted and experimentally validated that HIF-1α can exacerbate the expression of TGF-ß1 in a high glucose-dependent manner, revealing a novel role of HIF-1α in high glucose-induced pathological changes in human peritoneal mesothelial cells (HPMCs). CONCLUSIONS: In summary, our study provides a comprehensive view of the role of transcriptome deregulation and chromosome accessibility alterations in high glucose-induced pathological fibrotic changes in HPMCs. This analysis identified hub genes, signaling pathways, and key transcription factors involved in peritoneal fibrosis and highlighted the novel glucose-dependent regulation of TGF-ß1 by HIF-1α. This integrated approach has offered a deeper understanding of the pathogenesis of peritoneal fibrosis and has indicated potential therapeutic targets for intervention.

Coupling Osmotic Efficacy with Biocompatibility in Peritoneal Dialysis: A Stiff Challenge.

Peritoneal dialysis (PD) is a home-based efficacious modality for the replacement of renal function in end-stage kidney failure patients, but it is still under-prescribed. A major limitation is the durability of the dialytic technique. Continuous exposure of the peritoneum to bioincompatible conventional glucose-based solutions is thought to be the main cause of the long-term morpho-functional peritoneal changes that eventually result in ultrafiltration failure. Poor PD solution biocompatibility is primarily related to the high glucose content, which is not only detrimental to the peritoneal membrane but has many potential metabolic side effects. To improve the clinical outcome and prolong the survival of the treatment, PD-related bioincompatibility urgently needs to be overcome. However, combining dialytic and osmotic efficacy with a satisfactory biocompatible profile is proving to be quite difficult. New approaches targeting the composition of the PD solution include the replacement of glucose with other osmotic agents, and the addition of cytoprotective or osmo-metabolic compounds. Other strategies include the infusion of mesenchymal cells or the administration of orally active agents. In the present article, we review the current evidence on efforts to improve the biocompatible and functional performance of PD, focusing on studies performed in vivo (animal models of PD, human subjects on PD).

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.