TGF-β1-VEGF-A pathway induces neoangiogenesis with peritoneal fibrosis in patients undergoing 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.

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.

Melatonin decreases GSDME mediated mesothelial cell pyroptosis and prevents peritoneal fibrosis and ultrafiltration failure

Peritoneal fibrosis together with increased capillaries is the primary cause of peritoneal dialysis failure. Mesothelial cell loss is an initiating event for peritoneal fibrosis. We find that the elevated glucose concentrations in peritoneal dialysate drive mesothelial cell pyroptosis in a manner dependent on caspase-3 and Gasdermin E, driving downstream inflammatory responses, including the activation of macrophages. Moreover, pyroptosis is associated with elevated vascular endothelial growth factor A and C, two key factors in vascular angiogenesis and lymphatic vessel formation. GSDME deficiency mice are protected from high glucose induced peritoneal fibrosis and ultrafiltration failure. Application of melatonin abrogates mesothelial cell pyroptosis through a MT1R-mediated action, and successfully reduces peritoneal fibrosis and angiogenesis in an animal model while preserving dialysis efficacy. Mechanistically, melatonin treatment maintains mitochondrial integrity in mesothelial cells, meanwhile activating mTOR signaling through an increase in the glycolysis product dihydroxyacetone phosphate. These effects together with quenching free radicals by melatonin help mesothelial cells maintain a relatively stable internal environment in the face of high-glucose stress. Thus, Melatonin treatment holds some promise in preserving mesothelium integrity and in decreasing angiogenesis to protect peritoneum function in patients undergoing peritoneal dialysis.

Hyperglycolysis in endothelial cells drives endothelial injury and microvascular alterations in peritoneal dialysis

BACKGROUND

Endothelial cell (EC) dysfunction leading to microvascular alterations is a hallmark of technique failure in peritoneal dialysis (PD). However, the mechanisms underlying EC dysfunction in PD are poorly defined.

METHODS

We combined RNA sequencing with metabolite set analysis to characterize the metabolic profile of peritoneal ECs from a mouse model of PD. This was combined with EC-selective blockade of glycolysis by genetic or pharmacological inhibition of 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) in vivo and in vitro. We also investigated the association between peritoneal EC glycolysis and microvascular alterations in human peritoneal samples from patients with end-stage kidney disease (ESKD).

RESULTS

In a mouse model of PD, peritoneal ECs had a hyperglycolytic metabolism that shunts intermediates into nucleotide synthesis. Hyperglycolytic mouse peritoneal ECs displayed a unique active phenotype with increased proliferation, permeability and inflammation. The active phenotype of mouse peritoneal ECs can be recapitulated in human umbilical venous ECs and primary human peritoneal ECs by vascular endothelial growth factor that was released from high glucose-treated mesothelial cells. Importantly, reduction of peritoneal EC glycolysis, via endothelial deficiency of the glycolytic activator PFKFB3, inhibited PD fluid-induced increases in peritoneal capillary density, vascular permeability and monocyte extravasation, thereby protecting the peritoneum from the development of structural and functional damages. Mechanistically, endothelial PFKFB3 deficiency induced the protective effects in part by inhibiting cell proliferation, VE-cadherin endocytosis and monocyte-adhesion molecule expression. Pharmacological PFKFB3 blockade induced a similar therapeutic benefit in this PD model. Human peritoneal tissue from patients with ESKD also demonstrated evidence of increased EC PFKFB3 expression associated with microvascular alterations and peritoneal dysfunction.

CONCLUSIONS

These findings reveal a critical role of glycolysis in ECs in mediating the deterioration of peritoneal function and suggest that strategies targeting glycolysis in peritoneal ECs may be of therapeutic benefit for patients undergoing PD.

Manipulating TGF-β signaling to optimize immunotherapy for cervical cancer

Cervical cancer is a serious threat to women's health globally. Therefore, identifying key molecules associated with cervical cancer progression is essential for drug development, disease monitoring, and precision therapy. Recently, TGF-β (transforming growth factor-beta) has been identified as a promising target for cervical cancer treatment. For advanced cervical cancer, TGF-β participates in tumor development by improving metastasis, stemness, drug resistance, and immune evasion. Accumulating evidence demonstrates that TGF-β blockade effectively improves the therapeutic effects, especially immunotherapy. Currently, agents targeting TGF-β and immune checkpoints such as PD-L1 have been developed and tested in clinical studies. These bispecific antibodies might have the potential as therapeutic agents for cervical cancer treatment in the future.

Peritoneal transformation shortly after kidney transplantation in pediatric patients with preceding chronic peritoneal dialysis

BACKGROUND

The unphysiological composition of peritoneal dialysis (PD) fluids induces progressive peritoneal fibrosis, hypervascularization and vasculopathy. Information on these alterations after kidney transplantation (KTx) is scant.

METHODS

Parietal peritoneal tissues were obtained from 81 pediatric patients with chronic kidney disease stage 5 (CKD5), 72 children on PD with low glucose degradation product (GDP) PD fluids, and from 20 children 4-8 weeks after KTx and preceding low-GDP PD. Tissues were analyzed by digital histomorphometry and quantitative immunohistochemistry.

RESULTS

While chronic PD was associated with peritoneal hypervascularization, after KTx vascularization was comparable to CKD5 level. Submesothelial CD45 counts were 40% lower compared with PD, and in multivariable analyses independently associated with microvessel density. In contrast, peritoneal mesothelial denudation, submesothelial thickness and fibrin abundance, number of activated, submesothelial fibroblasts and of mesothelial-mesenchymal transitioned cells were similar after KTx. Diffuse peritoneal podoplanin positivity was present in 40% of the transplanted patients. In subgroups matched for age, PD vintage, dialytic glucose exposure and peritonitis incidence, submesothelial hypoxia-inducible factor 1-alpha abundance and angiopoietin 1/2 ratio were lower after KTx, reflecting vessel maturation, while arteriolar and microvessel p16 and cleaved Casp3 were higher. Submesothelial mast cell count and interleukin-6 were lower, whereas transforming growth factor-beta induced pSMAD2/3 was similar as compared with children on PD.

CONCLUSIONS

Peritoneal membrane damage induced with chronic administration of low-GDP PD fluids was less severe after KTx. While peritoneal microvessel density, primarily defining PD transport and ultrafiltration capacity, was normal after KTx and peritoneal inflammation less pronounced, diffuse podoplanin positivity and profibrotic activity were prevalent.

N-methylpiperazine-diepoxyovatodiolide ameliorates peritoneal fibrosis via suppressing TGF-β/Smad and JAK/STAT signaling pathway

Peritoneal fibrosis (PF) is the main cause of peritoneal ultrafiltration failure in patients undergoing long-term peritoneal dialysis (PD). Epithelial-mesenchymal transition (EMT) is the key pathogenesis of PF. However, currently, no specific treatments are available to suppress PF. N-methylpiperazine-diepoxyovatodiolide (NMPDOva) is a newly synthesized compound that involves a chemical modification of ovatodiolide. In this study, we aimed to explore the antifibrotic effects of NMPDOva in PD-related PF and underlying mechanisms. A mouse model of PD-related PF was established via daily intraperitoneal injection of 4.25% glucose PD fluid. In vitro studies were performed using the transforming growth factor-beta1 (TGF-β1)-stimulated HMrSV5 cell line. Pathological changes were observed, and fibrotic markers were significantly elevated in the peritoneal membrane in mice model of PD-related PF. However, NMPDOva treatment significantly alleviated PD-related PF by decreasing the extracellular matrix accumulation. NMPDOva treatment decreased the expression of fibronectin, collagen Ⅰ, and alpha-smooth muscle actin (α-SMA) in mice with PD-related PF. Moreover, NMPDOva could alleviate TGF-β1-induced EMT in HMrSV5 cells, inhibited phosphorylation and nuclear translocation of Smad2/3, and increased the expression of Smad7. Meanwhile, NMPDOva inhibited phosphorylation of JAK2 and STAT3. Collectively, these results indicated that NMPDOva prevents PD-related PF by inhibiting the TGF-β1/Smad and JAK/STAT signaling pathway. Therefore, because of these antifibrotic effects, NMPDOva may be a promising therapeutic agent for PD-related PF.

Therapeutic mechanism of baicalein in peritoneal dialysis-associated peritoneal fibrosis based on network pharmacology and experimental validation

Baicalein (5,6,7-trihydroxyflavone) is a traditional Chinese medicine with multiple pharmacological and biological activities including anti-inflammatory and anti-fibrotic effects. However, whether baicalein has a therapeutic impact on peritoneal fibrosis has not been reported yet. In the present study, network pharmacology and molecular docking approaches were performed to evaluate the role and the potential mechanisms of baicalein in attenuating peritoneal dialysis-associated peritoneal fibrosis. The results were validated in both animal models and the cultured human mesothelial cell line. Nine intersection genes among baicalein targets and the human peritoneum RNA-seq dataset including four encapsulating peritoneal sclerosis samples and four controls were predicted by network analysis. Among them, MMP2, BAX, ADORA3, HIF1A, PIM1, CA12, and ALOX5 exhibited higher expression in the peritoneum with encapsulating peritoneal sclerosis compared with those in the control, which might be crucial targets of baicalein against peritoneal fibrosis. Furthermore, KEGG and GO enrichment analyses suggested that baicalein played an anti-peritoneal fibrosis role through the regulating cell proliferation, inflammatory response, and AGE-RAGE signaling pathway. Moreover, molecular docking analysis revealed a strong potential binding between baicalein and MMP2, which was consistent with the predictive results. Importantly, using a mouse model of peritoneal fibrosis by intraperitoneally injecting 4.25% glucose dialysate, we found that baicalein treatment significantly attenuated peritoneal fibrosis, as evident by decreased collagen deposition, protein expression of α-SMA and fibronectin, and peritoneal thickness, at least, by reducing the expression of MMP2, suggesting that baicalein may have therapeutic potential in suppressing peritoneal dialysis-related fibrosis.

Photothermal Controlled-Release Immunomodulatory Nanoplatform for Restoring Nerve Structure and Mechanical Nociception in Infectious Diabetic Ulcers

Infectious diabetic ulcers (IDU) require anti-infection, angiogenesis, and nerve regeneration therapy; however, the latter has received comparatively less research attention than the former two. In particular, there have been few reports on the recovery of mechanical nociception. In this study, a photothermal controlled-release immunomodulatory hydrogel nanoplatform is tailored for the treatment of IDU. Due to a thermal-sensitive interaction between polydopamine-reduced graphene oxide (pGO) and the antibiotic mupirocin, excellent antibacterial efficacy is achieved through customized release kinetics. In addition, Trem2⁺ macrophages recruited by pGO regulate collagen remodeling and restore skin adnexal structures to alter the fate of scar formation, promote angiogenesis, accompanied by the regeneration of neural networks, which ensures the recovery of mechanical nociception and may prevent the recurrence of IDU at the source. In all, a full-stage strategy from antibacterial, immune regulation, angiogenesis, and neurogenesis to the recovery of mechanical nociception, an indispensable neural function of skin, is introduced to IDU treatment, which opens up an effective and comprehensive therapy for refractory IDU.

The Effects of Indobufen on Micro-Inflammation and Peritoneal Transport Function in Patients Undergoing Continuous Ambulate Peritoneal Dialysis: A Prospective Randomized Controlled Study

Indobufen possesses anticoagulant and antithrombotic effects that can improve micro-inflammation and renal function. This study aimed to examine whether indobufen could improve the microinflammatory state in patients on continuous ambulatory peritoneal dialysis (CAPD) and explore its therapeutic effects on peritoneal transport function. A total of 60 patients undergoing CAPD from October 2019 to October 2020 were selected and randomized to the control and indobufen groups. All patients received conventional treatments. Blood routine and the serum and peritoneal effusion levels of tumor necrosis factor-α (TNF-α), transforming growth factor-β1 (TGF-β1), cellular fibronectin (cFN), and vascular endothelial growth factor were determined before and after 6 months of treatment. The peritoneal equilibrium test (PET) was used to evaluate peritoneal transport function. There were no significant differences in PET results, microinflammatory state, and biochemical indices between the two groups before treatment (P > 0.05). After 6 months of treatment, platelet-to-lymphocyte ratio and serum and peritoneal effusion TNF-α levels in the indobufen group were decreased compared with the control group (P < 0.05). Serum and peritoneal effusion TGF-β1 and cFN levels in the indobufen group were reduced compared with the control group (P < 0.05). PET results in the indobufen group were decreased compared with baseline (P < 0.05). The difference in PET results between the two groups before and after treatment was statistically significant (P < 0.05). Indobufen could improve the peritoneal transport function in patients undergoing CAPD. The underlying mechanism might be related to the improvement of the microinflammatory state and peritoneal fibrosis. SIGNIFICANCE STATEMENT: Microinflammation and peritoneal fibrosis can lead to peritoneal failure in CAPD. Indobufen is a novel antiplatelet drug that can alleviate renal fibrosis and improve renal function in patients with diabetic nephropathy. Indobufen can improve the peritoneal transport function in patients undergoing CAPD. The mechanism of indobufen improving the peritoneal function might be related to the improvement of the microinflammatory state and peritoneal fibrosis.

Inhibition of Transglutaminase 2 Reduces Peritoneal Injury in a Chlorhexidine-Induced Peritoneal Fibrosis Model

Long-term peritoneal dialysis (PD) is often associated with peritoneal dysfunction leading to withdrawal from PD. The characteristic pathologic features of peritoneal dysfunction are widely attributed to peritoneal fibrosis and angiogenesis. The detailed mechanisms remain unclear, and treatment targets in clinical settings have yet to be identified. We investigated transglutaminase 2 (TG2) as a possible novel therapeutic target for peritoneal injury. TG2 and fibrosis, inflammation, and angiogenesis were investigated in a chlorhexidine gluconate (CG)-induced model of peritoneal inflammation and fibrosis, representing a noninfectious model of PD-related peritonitis. Transforming growth factor (TGF)-β type I receptor (TGFβR-I) inhibitor and TG2-knockout mice were used for TGF-β and TG2 inhibition studies, respectively. Double immunostaining was performed to identify cells expressing TG2 and endothelial-mesenchymal transition (EndMT). In the rat CG model of peritoneal fibrosis, in situ TG2 activity and protein expression increased during the development of peritoneal fibrosis, as well as increases in peritoneal thickness and numbers of blood vessels and macrophages. TGFβR-I inhibitor suppressed TG2 activity and protein expression, as well as peritoneal fibrosis and angiogenesis. TGF-β1 expression, peritoneal fibrosis, and angiogenesis were suppressed in TG2-knockout mice. TG2 activity was detected by α-smooth muscle actin-positive myofibroblasts, CD31-positive endothelial cells, and ED-1-positive macrophages. CD31-positive endothelial cells in the CG model were α-smooth muscle actin-positive, vimentin-positive, and vascular endothelial-cadherin-negative, suggesting EndMT. In the CG model, EndMT was suppressed in TG2-knockout mice. TG2 was involved in the interactive regulation of TGF-β. As inhibition of TG2 reduced peritoneal fibrosis, angiogenesis, and inflammation associated with TGF-β and vascular endothelial growth factor-A suppression, TG2 may provide a new therapeutic target for ameliorating peritoneal injuries in PD.

Telocyte-Derived Exosomes Provide an Important Source of Wnts That Inhibits Fibrosis and Supports Regeneration and Repair of Endometrium

Intrauterine adhesions (IUAs) often occurred after common obstetrical and gynecological procedures or infections in women of reproductive age. It was characterized by the formation of endometrial fibrosis and prevention of endometrial regeneration, usually with devastating fertility consequences and poor treatment outcomes so far. Telocytes (TCs), as a novel interstitial cell type, present in female uterus with in vitro therapeutic potential in decidualization-defective gynecologic diseases. This study aims to further investigate the role of TC-derived Wnt ligands carried by exosomes (Exo) in reversal of fibrosis and enhancement of regeneration repair in endometrium. IUA cellular and animal models were established from endometrial stromal cells (ESCs) and mice, followed with treatment of TC-conditioned medium (TCM) or TC-derived Exo. In cellular model, fibrosis markers (collagen type 1 alpha 1 [COL1A1], fibronectin [FN], and α-smooth muscle actin [α-SMA]), angiogenesis (vascular endothelial growth factor [VEGF]), and pathway protein (β-catenin) were determined by quantitative reverse transcription polymerase chain reaction (qRT-PCR), Western blotting (WB), and immunofluorescence. Results showed that, TCs (either TCM or TC-derived Exo) provide a source of Wnts that inhibit cellular fibrosis, as evidenced by significantly elevated VEGF and β-catenin with decreased fibrotic markers, whereas TCs lost salvage on fibrosis after being blocked with Wnt/β-catenin inhibitors (XAV939 or ETC-159). Further in mouse model, regeneration repair (endometrial thickness, number of glands, and fibrosis area ratio), fibrosis markers (fibronectin [FN]), mesenchymal-epithelial transition (MET) (E-cadherin, N-cadherin), and angiogenesis (VEGF, microvessel density [MVD]) were studied by hematoxylin-eosin (HE), Masson staining, and immunohistochemistry. Results demonstrated that TC-Exo treatment effectively promotes regeneration repair of endometrium by relieving fibrosis, enhancing MET, and angiogenesis. These results confirmed new evidence for therapeutic perspective of TC-derived Exo in IUAs.

Triamcinolone acetonide induces the autophagy of Ag85B-treated WI-38 cells via SIRT1/FOXO3 pathway

BACKGROUND

Tracheobronchial stenosis due to tuberculosis (TSTB) seriously threatens the health of tuberculosis patients. The inflammation and autophagy of fibroblasts affect the development of TSTB. Triamcinolone acetonide (TA) can regulate the autophagy of fibroblasts. Nevertheless, the impact of TA on TSTB and underlying mechanism has remained unclear.

OBJECTIVE

To study the impact of TA on TSTB and underlying mechanism.

MATERIAL AND METHODS

In order to simulate the TSTB-like model in vitro, WI-38 cells were exposed to Ag85B protein. In addition, the cell counting kit (CCK)-8 assay was applied to assess the function of TA in Ag85B-treated WI-38 cells. Quantitative real-time polymerase chain reaction was applied to detect the mRNA level of sirtuin 1 (SIRT1) and forkhead box O3 (FOXO3a), and autophagy-related proteins were evaluated by Western blot analysis. Vascular endothelial growth factor (VEGF) level was investigated by immunohistochemical staining. Enzyme-linked immunosorbent serologic assay was applied to detect the secretion of inflammatory cytokines. Furthermore, hematoxylin and eosin staining was applied to observe tissue injuries.

RESULTS

Ag85B affected WI-38 cell viability in a limited manner, while TA notably suppressed Ag85B-treated WI-38 cell viability. TA induced the apoptosis of Ag85B-treated WI-38 cells in a dose-dependent manner. In addition, Ag85B-treated WI-38 cells demonstrated the upregulation of interleukin (IL)-6, tumor necrosis factor-α (TNF-α), interferon gamma (IFN-γ), and fibrotic proteins (transforming growth factor-beta [TGF-β] and vascular endothelial growth factor [VEGF]), which can be significantly destroyed by the TA. Meanwhile, TA reversed Ag85-induced inhibition of cell autophagy by mediation of p62, LC3, and Beclin1. Furthermore, silencing of SIRT1/FOXO3a pathway could reverse the effect of TA on the autophagy of Ag85B-treated cells.

CONCLUSION

TA significantly induced the autophagy of fibroblasts in Ag85B-treated cells by mediation of SIRT1/FOXO3 pathway. This study established a new theoretical basis for exploring strategies against TSTB.

A Review on Major Pathways Leading to Peritoneal Fibrosis in Patients Receiving Continuous Peritoneal Dialysis

Peritoneal fibrosis (PF) is the most important complication of peritoneal dialysis (PD) that may arise among patients receiving continuous ambulatory peritoneal dialysis (CAPD). PF is a complex process, and many factors contribute to the formation of fibrosis. PD solutions with high glucose content, chronic inflammation, inflammatory cytokines, angiogenesis, and mesothelial to mesenchymal transition (MMT) are factors contributing to the fibrosis of the peritoneum. These factors, as well as stress-induced fibrosis, are going to be discussed further in this article. Although most experimental models are promising in preventing or delaying PD-related fibrosis, most of these recommended treatment options require further research. The lack of sufficient data from real PD patients and many inconclusive data make clinicians depend on conservative treatment. New therapeutics are indeed required for the management of patients undergoing PD to prevent the dreaded complication that may arise from continuous PD. Newer PD solutions are needed to improve survival and minimize the complication associated with PD. Recently, newer PD solutions have been shown to improve patient survival and peritoneal viability and reduce this complication that may arise as a result of continuous PD.

Glucose degradation products in peritoneal dialysis solution impair angiogenesis by dysregulating angiogenetic factors in endothelial and vascular smooth muscle cells

BACKGROUND

The accumulation of glucose degradation products (GDPs) during peritoneal dialysis (PD) can lead to immature angiogenesis in the peritoneum. However, the effect of GDPs on angiogenesis, at concentrations observed in dialysate effluent, has not been widely investigated. We do not know how the inflammation observed in PD-related peritonitis affects angiogenesis of the peritoneum.

METHODS

Human umbilical vessel endothelial cells (HUVEC) and human umbilical aortic smooth muscle cells (HUASMC) were used to examine the response to the three main GDPs found in peritoneal dialysate (methylglyoxal (MGO), 3-deoxyglucosone (3-DG), and 5-hydroxymethylfurfural (5-HMF). Supernatant from lipopolysaccharide (LPS)-activated murine macrophage cell lines (RAW 264.7 cells) were used to stimulate angiogenesis in the peritoneum. Changes in the expression of vascular endothelial growth factor-A (VEGF-A) and platelet-derived growth factor B (PDGFB) in HUVEC, and PDGF-receptor beta (PDGF-Rβ) in HUASMC, were examined by real-time PCR, Western blot, and ELISA.

RESULTS

In HUVECs, the expression of PDGFB mRNA and protein were decreased by exposure to MGO, 3-DG, and 5-HMF at concentrations observed in dialysate effluent. A subsequent decrease in secreted PDGF-BB was observed. In HUASMCs, MGO and 5-HMF increased the expression of VEGF-A mRNA and protein, while 5-HMF decreased the expression of PDGF-Rβ. VEGF-A is upregulated, and PDGF-Rβ is downregulated, by conditioned medium of LPS-stimulated macrophages in HUASMCs.

CONCLUSIONS

The GDPs of PD effluent cause an imbalance of angiogenic factors in endothelial cells and vascular smooth muscle cells that may lead to immature angiogenesis in the peritoneum.

Differentially Expressed microRNAs in Peritoneal Dialysis Effluent-Derived Exosomes from the Patients with Ultrafiltration Failure

Background

Ultrafiltration failure remains one of the most severe complications of long-term peritoneal dialysis (PD), which results in death. This study aimed to characterize the circulating exosomal microRNA (miRNA) profiles associated with ultrafiltration failure and explore its underlying mechanisms.

Methods

Exosomes were isolated from the peritoneal dialysis effluent (PDE) of patients with ultrafiltration failure or success using the ultracentrifugation method, and then transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and western blot were used for exosome characterization. After that, the isolated exosomes were sent for small RNA sequencing, and eight differentially expressed miRNAs (DE-miRNAs) were chosen for RT-qPCR validation.

Results

TEM, NTA, and western blot revealed that exosomes were successfully isolated. After sequencing, 70 DE-miRNAs involved in ultrafiltration were identified, including 41 upregulated ones and 29 downregulated ones. Functional analyses revealed that these DE-miRNAs were significantly enriched in pathways of cancer, ubiquitin-mediated proteolysis, axon orientation, and the Rap1 and Ras signaling pathways. In addition, the consistency rate of RT-qPCR and sequencing results was 75%, which indicated the relatively high reliability of the sequencing data.

Conclusions

Our findings implied that these DE-miRNAs may be potential biomarkers of ultrafiltration failure, which would help us to discover novel therapeutic targets/pathways for ultrafiltration failure in patients with end-stage renal disease.

Impacto das diferentes modalidades de diálise peritoneal automatizada sobre o perfil inflamatório de idosos portadores de doença renal crônica

Resumo Introdução: A doença renal crônica, mais prevalente em idosos, é considerada um problema de saúde pública em todo o mundo. Objetivo: Avaliar o impacto das modalidades de diálise peritoneal automatizada, intermitente e contínua, no perfil inflamatório de idosos renais crônicos. Métodos: Estudo prospectivo, transversal e analítico realizado em uma clínica de diálise em Brasília, com 74 idosos com idade igual ou maior que 60 anos. Os pacientes foram submetidos ao Teste de Equilíbrio Peritoneal rápido, avaliação clínica, coleta de sangue para avaliações bioquímicas e de citocinas, interleucina 6 e fator de crescimento transformador beta 1, e questionário de qualidade de vida (KDQOL-SF36). Foram utilizadas para análise dos dados, associações e correlações com nível de significância de 5%. Resultados: Pacientes na modalidade contínua apresentaram valores séricos do fator de crescimento transformador beta 1 maiores do que os em modalidade intermitente. Estes apresentaram fator de crescimento transformador beta 1 no peritônio, idade e função renal residual maiores do que os em modalidade contínua. A dosagem da interleucina 6 no peritônio foi associada à idade, enquanto a IL-6 sérica foi associada à IL-6 no peritônio, ao tempo em diálise e à idade. Não houve associação entre a modalidade e a presença de diabetes, volemia ou estado nutricional. Ambas as modalidades permitem boa adequação à terapia dialítica. Conclusão: A inflamação na diálise peritoneal automatizada está associada principalmente à baixa função renal residual, à idade avançada e ao maior tempo em terapia, e não à modalidade de diálise realizada.

Impact of different automated peritoneal dialysis modalities on the inflammatory profile of elderly patients with chronic kidney disease

INTRODUCTION

Chronic kidney disease, more prevalent in the elderly, is considered a public health issue worldwide.

OBJECTIVE

To evaluate the impact of automated, peritoneal dialysis modalities, intermittent and continuous, on the inflammatory profile of elderly people with chronic kidney disease.

METHODS

Prospective, cross-sectional and analytical study carried out in a dialysis clinic in Brasília - Brazil, with 74 elderly people aged 60 years or older. The patients underwent rapid Peritoneal Equilibration Test, clinical assessment, blood collection for biochemical and cytokine assessments, interleukin 6 and transforming growth factor beta 1, and answered a quality-of-life questionnaire (KDQOL-SF36). We used a 5% significance level for data analysis, associations and correlations.

RESULTS

Patients in the continuous modality had higher serum values of transforming growth factor beta 1 than those in the intermittent modality, which had higher peritoneal transforming growth factor beta 1, age and residual renal function than those in continuous mode. Interleukin 6 dosage in the peritoneum was associated with age, while serum IL-6 was associated with IL-6 in the peritoneum, time on dialysis and age. There was no association between the modality and the presence of diabetes, blood volume or nutritional status. Both modalities enable good adaptation to the dialysis treatment.

CONCLUSION

Inflammation in automated peritoneal dialysis is mainly associated with low residual renal function, advanced age and longer time on therapy, and not to the type of dialysis performed.

Fibrosis of Peritoneal Membrane as Target of New Therapies in Peritoneal Dialysis

Peritoneal dialysis (PD) is an efficient renal replacement therapy for patients with end-stage renal disease. Even if it ensures an outcome equivalent to hemodialysis and a better quality of life, in the long-term, PD is associated with the development of peritoneal fibrosis and the consequents patient morbidity and PD technique failure. This unfavorable effect is mostly due to the bio-incompatibility of PD solution (mainly based on high glucose concentration). In the present review, we described the mechanisms and the signaling pathway that governs peritoneal fibrosis, epithelial to mesenchymal transition of mesothelial cells, and angiogenesis. Lastly, we summarize the present and future strategies for developing more biocompatible PD solutions.

The functional multipotency of transforming growth factor β signaling at the intersection of senescence and cancer

The transforming growth factor β (TGF-β) family of cytokines comprises a group of proteins, their receptors, and effector molecules that, in a coordinated manner, modulate a plethora of physiological and pathophysiological processes. TGF-β1 is the best known and plausibly most active representative of this group. It acts as an immunosuppressant, contributes to extracellular matrix remodeling, and stimulates tissue fibrosis, differentiation, angiogenesis, and epithelial-mesenchymal transition. In recent years, this cytokine has been established as a vital regulator of organismal aging and cellular senescence. Finally, the role of TGF-β1 in cancer progression is no longer in question. Because this protein is involved in so many, often overlapping phenomena, the question arises whether it can be considered a molecular bridge linking some of these phenomena together and governing their reciprocal interactions. In this study, we reviewed the literature from the perspective of the role of various TGF-β family members as regulators of a complex mutual interplay between senescence and cancer. These aspects are then considered in a broader context of remaining TGF-β-related functions and coexisting processes. The main narrative axis in this work is centered around the interaction between the senescence of normal peritoneal cells and ovarian cancer cells. The discussion also includes examples of TGF-β activity at the interface of other normal and cancer cell types.

Xenogeneic skin transplantation promotes angiogenesis and tissue regeneration through activated Trem2+ macrophages

Skin allo- and xenotransplantation are the standard treatment for major burns when donor sites for autografts are not available. The relationship between the immune response to foreign grafts and their impact on wound healing has not been fully elucidated. Here, we investigated changes in collagen architecture after xenogeneic implantation of human biologic scaffolds. We show that collagen deposition in response to the implantation of human split-thickness skin grafts (hSTSGs) containing live cells recapitulates normal skin architecture, whereas human acellular dermal matrix (ADM) grafts led to a fibrotic collagen deposition. We show that macrophage differentiation in response to hSTSG implantation is driven toward regenerative Trem2+ subpopulations and found that hydrogel delivery of these cells significantly accelerated wound closure. Our study identifies the preclinical therapeutic potential of Trem2+ macrophages to mitigate fibrosis and promote wound healing, providing a novel effective strategy to develop advanced cell therapies for complex wounds.

Injectable self-assembling peptide nanofiber hydrogel as a bioactive 3D platform to promote chronic wound tissue regeneration

Chronic wounds remain a worldwide clinical challenge, and bioactive materials that can promote skin regeneration are required. Self-assembling peptide (SAP) hydrogels have shown great potential in tissue repair, but their regenerative efficacy and possible mechanism in chronic wound healing are unclear. Here, we report an SAP (KGH) that enhances extracellular matrix (ECM) remodeling and angiogenesis, thereby promoting chronic wound healing in diabetic mice. In vivo, the KGH hydrogel was retained in wounds up to 7 days after injection, and it was effective in speeding up wound closure by ∼20% compared to the control groups and enhancing angiogenesis (e.g., VEGFA, CD31⁺ capillaries), cell proliferation (e.g., PCNA⁺ cells), formation of granulation tissue (e.g., α-SMA), and ECM deposition/remodeling (e.g., collagen I, fibronectin). In vitro, the KGH hydrogel created a 3D microenvironment for skin cells, maintained the sustained growth of cell spheroids, and increased the secretion of ECM proteins (e.g., laminin) and growth factors (e.g., PDGFB, VEGFA, and TGF-β) in skin keratinocytes compared to the conventional 2D culture. Mechanistically, the KGH hydrogel might promote wound tissue regeneration by activating the Rho/ROCK and TGF-β/MEK/MAPK pathways. As a type of designed material, SAP can be further re-engineered with biological motifs, therapeutic reagents, or stem cells to enhance skin regeneration. This study highlights that SAP hydrogels are a promising material platform for advanced chronic wound healing and might have translational potential in future clinical applications. STATEMENT OF SIGNIFICANCE: Chronic wounds are a common and serious health issue worldwide, and bioactive dressing materials are required to address this issue. SAP hydrogels have shown certain tissue repair potential, but their regenerative efficacy and underlying mechanism in chronic wound healing remain elusive. Herein, we report that SAP hydrogels create a native 3D microenvironment that can remarkably stimulate angiogenesis and ECM remodeling in diabetic wounds. Mechanistically, the SAP hydrogel promoted ECM proteins and GFs secretion in skin cells through the activation of the Rho/ROCK and TGF-ß/MEK/MAPK pathways. Additionally, SAP can be readily engineered with various bioactive motifs or therapeutic drugs/cells. This work highlights SAP hydrogels as a promising biomaterial platform for chronic wound healing and the regeneration of many other tissues.

ACEi/ARBs associate with lower incidence of gastrointestinal bleeding in peritoneal dialysis patients

BACKGROUND

Gastrointestinal bleeding (GIB) is widespread in patients with impaired renal function. Whether angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers (ACEi/ARBs) potentially take a crucial role in avoiding GIB incidence among peritoneal dialysis (PD) patients is unknown.

METHODS

Overall, 734 PD patients were enrolled after using propensity score matching. Kaplan-Meier analysis and COX regression were used to explore correlation between ACEi/ARBs and GIB. Competitive risk model was aimed to identify whether other events were confounding factors. Forest plot was applied to assess the influence of ACEI/ARBs on GIB incidence in different groups.

RESULTS

During 8-year follow-up, 89 (12.13%) cases of GIB were recorded. Kaplan-Meier analysis revealed that the incidence of GIB among patients taking ACEi/ARBs was lower than those subjects who had not (log rank = 6.442, P = 0.011). After adjusted different confounding factors, administration of ACEi/ARBs was associated with lowered GIB incidence (adjusted HR = 0.49, 95% CI 0.32-0.77, P = 0.002). In competitive risk model, considering of other events, the incidence of GIB in two groups was still statistically significant (P = 0.010). Subgroup analysis showed ACEi/ARBs taking impeded GIB in the ≥ 60 age group (HR = 0.52, 95% CI 0.28-0.98, P = 0.040).

CONCLUSION

PD patients who were submitted to ACEi/ARBs inclined to have a lower risk for GIB. In this regard, ACEi/ARBs offered a promising choice to GIB.

Lithium preserves peritoneal membrane integrity by suppressing mesothelial cell αB-crystallin

Life-saving renal replacement therapy by peritoneal dialysis (PD) is limited in use and duration by progressive impairment of peritoneal membrane integrity and homeostasis. Preservation of peritoneal membrane integrity during chronic PD remains an urgent but long unmet medical need. PD therapy failure results from peritoneal fibrosis and angiogenesis caused by hypertonic PD fluid (PDF)-induced mesothelial cytotoxicity. However, the pathophysiological mechanisms involved are incompletely understood, limiting identification of therapeutic targets. We report that addition of lithium chloride (LiCl) to PDF is a translatable intervention to counteract PDF-induced mesothelial cell death, peritoneal membrane fibrosis, and angiogenesis. LiCl improved mesothelial cell survival in a dose-dependent manner. Combined transcriptomic and proteomic characterization of icodextrin-based PDF-induced mesothelial cell injury identified αB-crystallin as the mesothelial cell protein most consistently counter-regulated by LiCl. In vitro and in vivo overexpression of αB-crystallin triggered a fibrotic phenotype and PDF-like up-regulation of vascular endothelial growth factor (VEGF), CD31-positive cells, and TGF-β-independent activation of TGF-β-regulated targets. In contrast, αB-crystallin knockdown decreased VEGF expression and early mesothelial-to-mesenchymal transition. LiCl reduced VEGF release and counteracted fibrosis- and angiogenesis-associated processes. αB-crystallin in patient-derived mesothelial cells was specifically up-regulated in response to PDF and increased in peritoneal mesothelial cells from biopsies from pediatric patients undergoing PD, correlating with markers of angiogenesis and fibrosis. LiCl-supplemented PDF promoted morphological preservation of mesothelial cells and the submesothelial zone in a mouse model of chronic PD. Thus, repurposing LiCl as a cytoprotective PDF additive may offer a translatable therapeutic strategy to combat peritoneal membrane deterioration during PD therapy.

VEGF-mediated angiogenesis in retinopathy of prematurity is co-regulated by miR-17-5p and miR-20a-5p

The microRNAs miR-17-5p and miR-20a-5p play important roles on angiogenesis; however, it is arguable whether they regulate the formation of retinal blood vessels in retinopathy of prematurity (ROP). We used a mouse model of oxygen-induced retinopathy (OIR) to simulate the development of retinas in mice suffering from ROP, and the expression levels of miR-20a-5p, miR-17-5p, hypoxia-inducible factor 1-alpha (HIF-1α), and vascular endothelial growth factor (VEGF) were measured by RT-qPCR and Western blotting. Cell proliferation, apoptosis, and angiogenesis in the OIR model mice were measured using MTT assays, flow cytometry, and Matrigel assays, respectively. The interaction between HIF-1α/VEGF and miR-20a-5p/miR-17-5p were further validated using dual-luciferase reporter assays, biotin-labeled RNA-pulldown, and RNA immunoprecipitation (RIP) assays. In our OIR model, retinal angiogenesis in the mice was associated with down-regulation of miR-20a-5p and miR-17-5p, as well as up-regulation of HIF-1α and VEGF. In addition, the miR-20a-5p and miR-17-5p inhibited cell proliferation and angiogenesis through regulating HIF-1α and VEGF in the retinal cells of the OIR model mice. Moreover, it was found that miR-20a-5p and miR-17-5p bind to HIF-1α and VEGF at the 3'UTR, and there was a combined effect between miR-20a-5p and miR-17-5p on the regulation of HIF-1α and VEGF. It is worth noting that miR-17-5p and miR-20a-5p can preferentially regulate HIF-1α, then act on VEGF, thereby affecting the angiogenesis associated with ROP.

Elevated expression of HDAC6 in clinical peritoneal dialysis patients and its pathogenic role on peritoneal angiogenesis

Peritoneal dialysis (PD) is an important renal replacement therapy for end-stage renal disease (ESRD) patients. However, its complications, such as peritoneal fibrosis (PF) and angiogenesis can cause ultrafiltration failure and PD termination. Histone deacetylase 6 (HDAC6) has been demonstrated to be involved in PF. However, its underlying role in peritoneal angiogenesis is still unknown and clinical value needs to be explored. In this study, we analyzed the expression of HDAC6 in the peritoneum from patients with non-PD and PD-related peritonitis and dialysis effluent from stable PD patients. Our study revealed that HDAC6 expressed highly in the peritoneum with peritonitis and co-stained with α-smooth muscle actin (α-SMA), a biomarker of the myofibroblast. And the level of HDAC6 in the dialysate increased with time and positively correlated with transforming growth factor-β1 (TGF-β1), interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF), and negatively with cancer antigen 125 (CA125). In vitro, blockading HDAC6 with a selective inhibitor tubastatin A (TA) or silencing HDAC6 with a small interfering RNA (siRNA) prominently decreased IL-6-stimulated VEGF expression in cultured human peritoneal mesothelial cells (HPMCs), and inhibited proliferation and vasoformation of human umbilical vein endothelial cells (HUVECs). TA or HDAC6 siRNA also suppressed the expression of Wnt1, β-catenin, and the phosphorylation of STAT3 in IL-6-treated HPMCs. In summary, HDAC6 inhibition protects against PD-induced angiogenesis through suppression of IL-6/STAT3 and Wnt1/β-catenin signaling pathway, subsequently reducing the VEGF production and angiogenesis. It could become a new therapeutic target or forecast biomarker for PF, inflammation, and angiogenesis in the future.

Nintedanib attenuates peritoneal fibrosis by inhibiting mesothelial-to-mesenchymal transition, inflammation and angiogenesis

Nintedanib, an Food and Drug Administration (FDA) approved multiple tyrosine kinase inhibitor, exhibits an anti-fibrotic effect in lung and kidneys. Its effect on peritoneal fibrosis remains unexplored. In this study, we found that nintedanib administration lessened chlorhexidine gluconate (CG)-induced peritoneal fibrosis and reduced collagen I and fibronectin expression. This coincided with suppressed phosphorylation of platelet-derived growth factor receptor, fibroblast growth factor receptors, vascular endothelial growth factor receptor and Src family kinase. Mechanistically, nintedanib inhibited injury-induced mesothelial-to-mesenchymal transition (MMT), as demonstrated by decreased expression of α-smooth muscle antigen and vimentin and preserved expression of E-cadherin in the CG-injured peritoneum and cultured human peritoneal mesothelial cells exposed to transforming growth factor-β1. Nintedanib also suppressed expression of Snail and Twist, two transcription factors associated with MMT in vivo and in vitro. Moreover, nintedanib treatment inhibited expression of several cytokines/chemokines, including tumour necrosis factor-α, interleukin-1β and interleukin-6, monocyte chemoattractant protein-1 and prevented infiltration of macrophages to the injured peritoneum. Finally, nintedanib reduced CG-induced peritoneal vascularization. These data suggest that nintedanib may attenuate peritoneal fibrosis by inhibiting MMT, inflammation, and angiogenesis and have therapeutic potential for the prevention and treatment of peritoneal fibrosis in patients on peritoneal dialysis.

Inflammation-Mediated Angiogenesis in Ischemic Stroke

Stroke is the leading cause of disability and mortality in the world, but the pathogenesis of ischemic stroke (IS) is not completely clear and treatments are limited. Mounting evidence indicate that neovascularization is a critical defensive reaction to hypoxia that modulates the process of long-term neurologic recovery after IS. Angiogenesis is a complex process in which the original endothelial cells in blood vessels are differentiated, proliferated, migrated, and finally remolded into new blood vessels. Many immune cells and cytokines, as well as growth factors, are directly or indirectly involved in the regulation of angiogenesis. Inflammatory cells can affect endothelial cell proliferation, migration, and activation by secreting a variety of cytokines via various inflammation-relative signaling pathways and thus participate in the process of angiogenesis. However, the mechanism of inflammation-mediated angiogenesis has not been fully elucidated. Hence, this review aimed to discuss the mechanism of inflammation-mediated angiogenesis in IS and to provide new ideas for clinical treatment of IS.

Vascular endothelial growth factor-mediated peritoneal neoangiogenesis in peritoneal dialysis

Peritoneal dialysis (PD) is an important renal replacement therapy for patients with end-stage renal diseases, which is limited by peritoneal neoangiogenesis leading to ultrafiltration failure (UFF). Vascular endothelial growth factor (VEGF) and its receptors are key angiogenic factors involved in almost every step of peritoneal neoangiogenesis. Impaired mesothelial cells are the major sources of VEGF in the peritoneum. The expression of VEGF will be up-regulated in specific pathological conditions in PD patients, such as with non-biocompatible peritoneal dialysate, uremia and inflammation, and so on. Other working cells (i.e. vascular endothelial cells, macrophages and adipocytes) can also stimulate the secretion of VEGF. Meanwhile, hypoxia and activation of complement system further aggravate peritoneal injury and contribute to neoangiogenesis. There are several signalling pathways participating in VEGF-mediated peritoneal neoangiogenesis including tumour growth factor-β, Wnt/β-catenin, Notch and interleukin-6/signal transducer and activator of transcription 3. Moreover, VEGF is highly expressed in dialysate effluent of long-term PD patients and is associated with peritoneal transport function, which supports its role in the alteration of peritoneal structure and function. In this review, we systematically summarize the angiogenic effect of VEGF and evaluate it as a potential target for the prevention of peritoneal neoangiogenesis and UFF. Preservation of the peritoneal membrane using targeted therapy of VEGF-mediated peritoneal neoangiogenesis may increase the longevity of the PD modality for those who require life-long dialysis.

C1 inhibitor mitigates peritoneal injury in zymosan-induced peritonitis

Peritonitis, due to a fungal or bacterial infection, leads to injury of the peritoneal lining and thereby forms a hazard for the long-term success of peritoneal dialysis (PD) and remains a lethal complication in patients with PD. This study investigated whether C1 inhibitor (C1-INH) could protect against the progression of peritoneal injuries with five daily administrations of zymosan after mechanical scraping of the rat peritoneum to mimic fungal peritonitis. Severe peritoneal injuries were seen in this model, accompanied by fibrinogen/fibrin exudation and peritoneal deposition of complement activation products such as activated C3 and C5b-9. However, intraperitoneal injection of C1-INH decreased peritoneal depositions of activated C3 and C5b-9, ameliorated peritoneal thickening, reduced the influx of inflammatory cells, and prevented the production of peritoneal fibrous layers with both one and two doses of C1-INH each day. Our results suggest that C1-INH might be useful to protect against peritoneal injuries after causes of peritonitis such as fungal infection. This clinically available agent may thus help extend the duration of PD.NEW & NOTEWORTHY Peritoneal injuries associated with peritonitis comprise an important issue to prevent long-term peritoneal dialysis (PD) therapy. Here, we showed that C1 inhibitor (C1-INH), as an anticomplement agent, protected against peritoneal injuries in a peritonitis animal model related to fungal infection. Therefore, C1-INH might be useful to protect against peritoneal injuries after peritonitis due to fungal infection. This clinically available agent may thus help extend the duration of PD.

Use of icodextrin solution to evaluate peritoneal transport capacity

Peritoneal equilibration test (PET) is the gold standard for evaluating peritoneal transport, and measurement of the drain volume after 4-h dwell time with glucose 4.25% is a simple means of evaluating failure of ultrafiltration. The study objective was to verify if the measurement of the volume drained after 4 h dwell of icodextrin at 7.5% (ICO), has a better correlation with the parameters of PET. Patients in a peritoneal dialysis program (N = 35) underwent three procedures: PET; determination of the drain volume after a 4-h dwell with glucose 4.25%; and determination of the drain volume after a 4-h dwell with ICO. Among patients who were classified as high transporters, the ultrafiltration volume was greater after ICO use. The ICO ultrafiltration volume correlated negatively with the ratio between the 4- and 0-h dialysate glucose concentrations (D4/D0 ratio, r = -0.579; P = 0.002), correlating positively with the dialysate-to-plasma ratio for creatinine (D/PCr ratio, r = 0.474; P = 0.002). For ICO, the area under the receiver operating characteristic curve was 0.867 and 0.792 for the D/PCr and D4/D0 ratios (P < 0.0001 and P = 0.004, respectively), compared with 0.738 and 0.710 for glucose 4.25% (P = 0.020 and P = 0.041, respectively). A cut-off volume of 141 mL discriminated high/high-average transporters from low/low-average transporters. Volume drained after ICO use better predicts peritoneal transport patterns than does that drained after the use of glucose 4.25%.

Association between genetic variants in the HIF1A-VEGF pathway and left ventricular regional myocardial deformation in patients with hypertrophic cardiomyopathy

BACKGROUND

Information on genetic etiology of pediatric hypertrophic cardiomyopathy (HCM) rarely aids in risk stratification and prediction of disease onset. Little data exist on the association between genetic modifiers and phenotypic expression of myocardial performance, hampering an individual precision medicine approach.

METHODS

Single-nucleotide polymorphism genotyping for six previously established disease risk alleles in the hypoxia-inducible factor-1α-vascular endothelial growth factor pathway was performed in a pediatric cohort with HCM. Findings were correlated with echocardiographic parameters of systolic and diastolic myocardial deformation measured by two-dimensional (2-D) speckle-tracking strain.

RESULTS

Twenty-five children (6.1 ± 4.5 years; 69% male) with phenotypic and genotypic (60%) HCM were included. Out of six risk alleles tested, one, VEGF1 963GG, showed an association with reduced regional systolic and diastolic left ventricular (LV) myocardial deformation. Moreover, LV average and segmental systolic and diastolic strain and strain rate were significantly reduced, as assessed by the standardized difference, in patients harboring the risk allele.

CONCLUSIONS

This is the first study to identify an association between a risk allele in the VEGF pathway and regional LV myocardial function, with the VEGF1 963GG allele associated with reduced LV systolic and diastolic myocardial performance. While studies are needed to link this information to adverse clinical outcomes, this knowledge may help in risk stratification and patient management in HCM.

IMPACT

Risk allele in the VEGF gene impacts on LV myocardial deformation phenotype in children with HCM. LV 2-D strain is significantly reduced in patients with risk allele compared to non-risk allele patients within HCM patient groups. Describes that deficiencies in LV myocardial performance in children with HCM are associated with a previously identified risk allele in the angiogenic transcription factor VEGF. First study to identify an association between a risk allele in the VEGF pathway and regional LV myocardial deformation measured by 2-D strain in children with HCM.

Timing urinary tract reconstruction in rats to avoid hydronephrosis and fibrosis in the transplanted fetal metanephros as assessed using imaging

Chronic kidney disease leads to high morbidity rates among humans. Kidney transplantation is often necessary for severe symptoms; however, options for new curative treatments are desired because of donor shortage. For example, it has been established that the kidneys can efficiently generate urine after transplantation of the metanephros, ureter, and bladder as a group. After transplantation, the urine can indirectly flow into the recipient's bladder using a stepwise peristaltic ureter system method where the anastomosis is created via the recipient's ureter for urinary tract reconstruction. However, the growth of the regenerated metanephros varies significantly, whereas the time window for successful completion of the stepwise peristaltic ureter system that does not cause hydronephrosis of the metanephros with bladder (ureter) is quite narrow. Therefore, this study was conducted to periodically and noninvasively evaluate the growth of the transplanted metanephros, ureter, and bladder in rats through computed tomography and ultrasonography. The ultrasonographic findings highly correlated to the computed tomography findings and clearly showed the metanephros and bladder. We found that the degree of growth of the metanephros and the bladder after transplantation differed in each case. Most of the rats were ready for urinary tract reconstruction within 21 days after transplantation. Optimizing the urinary tract reconstruction using ultrasonography allowed for interventions to reduce long-term tubular dilation of the metanephros due to inhibited overdilation of the fetal bladder, thereby decreasing the fibrosis caused possibly by transforming growth factor-β1. These results may be significantly related to the long-term maturation of the fetal metanephros and can provide new insights into the physiology of transplant regeneration of the metanephros in higher animals. Thus, this study contributes to the evidence base for the possibility of kidney regeneration in human clinical trials.

Identification of key genes and pathways in scleral extracellular matrix remodeling in glaucoma: Potential therapeutic agents discovered using bioinformatics analysis

Background: Glaucoma is a leading cause of irreversible blindness. Remodeling of the scleral extracellular matrix (ECM) plays an important role in the development of glaucoma. The aim of this study was to identify the key genes and pathways for the ECM remodeling of sclera in glaucoma by bioinformatics analysis and to explore potential therapeutic agents for glaucoma management. Methods: Genes associated with glaucoma, sclera and ECM remodeling were detected using the text mining tool pubmed2ensembl, and assigned Gene Ontology (GO) biological process terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways using the GeneCodis program. A protein-protein interaction (PPI) network was constructed by STRING and visualized in Cytoscape, module analysis was performed using the Molecular Complex Detection (MCODE) plugin, and GO and KEGG analyses of the gene modules were performed using the Database of Annotation, Visualization and Integrated Discovery (DAVID) platform. The genes that clustered in the significant module were selected as core genes, and functions and pathways of the core genes were visualized using ClueGO and CluePedia. Lastly, the drug-gene interaction database was used to explore drug-gene interactions of the core genes to find drug candidates for glaucoma. Results: We identified 125 genes common to "Glaucoma", "Sclera", and "ECM remodeling" by text mining. Gene functional enrichment analysis yielded 30 enriched GO terms and 20 associated KEGG pathways. A PPI network that included 60 nodes with 249 edges was constructed, and three gene modules were obtained using the MCODE. We selected 13 genes that clustered in module 1 as core candidate genes that were associated mainly with ECM degradation and cell proliferation and division. The HIF-1 signaling pathway, FOXO signaling pathway, PI3K-Akt signaling pathway and TGFB signaling pathway were found to be enriched. We found that 11 of the 13 selected genes could be targeted by 26 existing drugs. Conclusions: The results showed that VEGFA, TGFB1, TGFB2, TGFB3, IGF2, IGF1, EGF, FN1, KNG1, TIMP1, SERPINE1, THBS1, and VWF were potential key genes involved to scleral ECM remodeling. Furthermore, 26 drugs were identified as potential therapeutic agents for glaucoma treatment and management.

Molecular pathways in peritoneal fibrosis

Peritoneal dialysis (PD) is a renal replacement therapy for patients with end-stage renal disease that is equivalent to hemodialysis with respect to adequacy, mortality, and other outcome parameters, yet providing superior quality-of-life measures and cost savings. However, long-term usage of the patient's peritoneal membrane as a dialyzer filter is unphysiological and leads to peritoneal fibrosis, which is a major factor of patient morbidity and PD technique failure, resulting in a transfer to hemodialysis or death. Peritoneal fibrosis pathophysiology involves chronic inflammation and the fibrotic process itself. Frequently, inflammation precedes membrane fibrosis development, although a bidirectional relationship of one inducing the other exists. This review aims at highlighting the histopathological definition of peritoneal fibrosis, outlining the interplay of fibrosis, angiogenesis and epithelial-to-mesenchymal transition (EMT), delineating important fibrogenic pathways involving Smad-dependent and Smad-independent transforming growth factor-β (TGF-β) as well as connective tissue growth factor (CTGF) signaling, and summarizing historic and recent studies of inflammatory pathways involving NOD-like receptor protein 3 (NLRP3)/interleukin (IL)-1β, IL-6, IL-17, and other cytokines.

Effect of bevacizumab and everolimus combination treatment on peritoneal sclerosis in an experimental rat model

The aim of this study was to investigate whether bevacizumab and everolimus combination therapy is superior to bevacizumab treatment alone as a treatment for peritoneal sclerosis. Forty Wistar albino rats were divided into five equal groups. The control group received isotonic saline solution (2 mL/day) intraperitoneal (IP) daily for 3 weeks. The CG group received 2 mL 0.1% chlorhexidine gluconate (CG) and 15% ethanol dissolved in saline IP daily for 3 weeks. Peritoneal tissue samples were taken at the end of 3 weeks. The resting group received CG (weeks 0-3), plus isotonic saline solution (2 mL/day) IP daily and tap water (2 mL/day) via a feeding tube daily (weeks 3-6).The bevacizumab group received CG (weeks 1-3) plus bevacizumab at 2.5 mg/kg/day (2 mL) IP daily and tap water (2 mL/day) via a feeding tube daily (weeks 3-6). The bevacizumab+everolimus group received CG (weeks 1-3) plus bevacizumab at 2.5 mg/kg/day (2 mL) IP daily and everolimus at 0.3 mg/kg/day (2 mL) via a feeding tube daily (weeks 3-6). Peritoneal tissue samples were taken from these three groups at the end of 6 weeks and were examined after staining with hematoxylin-eosin and Masson's trichrome. Inflammation, vasculopathy, fibrosis, and peritoneal thickness were evaluated under light microscopy. The samples were also stained with anti-TGF-β and anti-MMP-2. Inflammation and vasculopathy scores were significantly decreased in the VEGF-i group compared to the CG group. The addition of everolimus to VEGF-i showed significantly lower inflammation, vasculopathy, fibrosis scores, and an evident decrease in peritoneal thickening (respectively, 2.29 ± 0.76 vs 0.57 ± 0.53, P = .003; 2.71 ± 0.76 vs 1.43 ± 0.53, P = .008; 2.57 ± 0.79 vs 1.57 ± 0.79, P = .04; 247.5 ± 136.1 vs 84.5 ± 48.6, P = .048). MMP-2 levels were lower in the combination group compared to the resting group (2.63 ± 0.74 vs 1.86 ± 0.38, P = .019). The study results demonstrated that bevacizumab and everolimus combination therapy was more effective than bevacizumab therapy alone.

Proteomic Research in Peritoneal Dialysis

Peritoneal dialysis (PD) is an established home care, cost-effective renal replacement therapy (RRT), which offers several advantages over the most used dialysis modality, hemodialysis. Despite its potential benefits, however, PD is an under-prescribed method of treating uremic patients. Infectious complications (primarily peritonitis) and bio-incompatibility of PD solutions are the main contributors to PD drop-out, due to their potential for altering the functional and anatomical integrity of the peritoneal membrane. To improve the clinical outcome of PD, there is a need for biomarkers to identify patients at risk of PD-related complications and to guide personalized interventions. Several recent studies have shown that proteomic investigation may be a powerful tool in the prediction, early diagnosis, prognostic assessment, and therapeutic monitoring of patients on PD. Indeed, analysis of the proteome present in PD effluent has uncovered several proteins involved in inflammation and pro-fibrotic insult, in encapsulating peritoneal sclerosis, or even in detecting early changes before any measurable modifications occur in the traditional clinical parameters used to evaluate PD efficacy. We here review the proteomic studies conducted thus far, addressing the potential use of such omics methodology in identifying potential new biomarkers of the peritoneal membrane welfare in relation to dialytic prescription and adequacy.

Peritoneal fibrosis and epigenetic modulation

Peritoneal dialysis (PD) is an effective treatment for patients with end-stage renal disease. However, peritoneal fibrosis (PF) is a common complication that ultimately leads to ultrafiltration failure and discontinuation of PD after long-term PD therapy. There is currently no effective therapy to prevent or delay this pathologic process. Recent studies have reported epigenetic modifications involved in PF, and accumulating evidence suggests that epigenetic therapies may have the potential to prevent and treat PF clinically. The major epigenetic modifications in PF include DNA methylation, histone modification, and noncoding RNAs. The mechanisms of epigenetic regulation in PF are complex, predominantly involving modification of signaling molecules, transcriptional factors, and genes. This review will describe the mechanisms of epigenetic modulation in PF and discuss the possibility of targeting them to prevent and treat this complication.

Increased Level of Vascular Endothelial Growth Factors by 4-hexylresorcinol is Mediated by Transforming Growth Factor-β1 and Accelerates Capillary Regeneration in the Burns in Diabetic Animals

4-Hexyl resorcinol (4HR) is an organic compound and has been used in skin care application. 4HR is an M2-type macrophage activator and elevates vascular endothelial growth factor (VEGF) expression via the hypoxia-inducible factor (HIF)-independent pathway. As endothelial cells are important in wound healing, the human umbilical vein endothelial cells (HUVECs) were treated with 4HR, and changes in VEGF-A, -C, and transforming growth factor-β1 (TGF-β1) expression were investigated. The administration of 4HR increased the expression level of VEGF-A, -C, and TGF-β1. The application of TGF-β1 protein also increased the expression level of VEGF-A and -C. Knockdown with small interfering RNA (siRNA) targeting to TGF-β1 and the selective chemical inhibition (A83-01) to ALK5 confirmed the involvement of the TGF-β signaling pathway in the 4-HR-mediated VEGFs expression. 4HR application in a burn model of diabetic rats demonstrated an increased level of angiogenic proteins with wound healing. Compared to sericin application, the 4HR application group showed more prominent capillary regeneration. Collectively, 4HR activated TGF-β1/ALK5/VEGFs signaling in endothelial cells and induced vascular regeneration and remodeling for wound healing.

High glucose contributes to the polarization of peritoneal macrophages to the M2 phenotype in vivo and in vitro

Glucose is the primary osmotic medium used in most peritoneal dialysis (PD) solutions, and long‑term exposure to high glucose is a major contributor to peritoneal fibrosis. Our previous study revealed that M2 macrophages participate in the development of PD‑related fibrosis in a rat model. In the present study, the effects of high glucose on peritoneal macrophage polarization in vivo and in vitro were further evaluated. Continuous ambulatory PD (CAPD) patients with an overnight dwell of 1.5 or 2.5% glucose dialysate were recruited for this study. Overnight effluent samples from patients with CAPD (2,000 ml) were centrifuged to collect cells from the peritoneal cavity. J774A.1 cells (murine macrophages from ascites) were cultured in different concentrations of glucose. Macrophage phenotype markers were detected by flow cytometry. The levels of cytokines in PD effluent and the supernatant of murine macrophages were detected by enzyme‑linked immunosorbent assays. The activity of arginase was determined by quantitative colorimetric analysis. In total, 107 CAPD subjects (92 patients using 1.5% glucose dialysate and 15 patients using 2.5% glucose dialysate) were recruited. The percentage of M1 macrophages (CD14‑ and CCr7‑positive cells) in the 1.5 and 2.5% glucose dialysate groups was 23.0±13.3 and 24.9±12.0%, respectively. The difference was not significant (P>0.05). The percentage of M2 macrophages (CD14‑ and CD206‑positive cells) in the 1.5% glucose dialysate group (36.2±11.4%) was significantly decreased compared to the 2.5% glucose dialysate group (43.2±7.4%) (P<0.05). Murine macrophages were cultured in a high‑glucose in vitro environment, and the percentage of M1 macrophages in 138.8 mmol/l glucose medium significantly increased over time. The percentage of M2 macrophages increased in a glucose concentration‑dependent and time‑dependent manner. Arginase 1 in murine macrophages and the level of transforming growth factor β1 in the supernatant increased in a glucose concentration‑dependent manner. In conclusion, high glucose contributed to the polarization of peritoneal macrophages to the M2 phenotype, which may play an important role in the pathogenesis of PD‑related fibrosis.

Excessive salt intake increases peritoneal solute transport rate via local tonicity-responsive enhancer binding protein in subtotal nephrectomized mice

BACKGROUND

High peritoneal transport is associated with high mortality and technical failure in peritoneal dialysis (PD). Baseline peritoneal solute transport rate (PSTR) as measured by the peritoneal equilibration test (PET) within 6 months after PD initiation varies between patients. Sodium is reported to be stored in the skin or muscle of dialysis patients. This study investigated whether excessive salt intake in uremic mice caused peritoneal alterations without exposure to PD fluid.

METHODS

Sham-operated (Sham) and subtotal nephrectomized (Nx) mice were randomly given tap water or 1% sodium chloride (NaCl)-containing water for 8 weeks. PET was then performed to evaluate peritoneal function. Human mesothelial cell line Met-5A was used for in vitro studies.

RESULTS

We observed higher PSTR in Nx mice with 1% NaCl-containing drinking water (Nx + salt) compared with those with tap water (Nx + water), along with enhanced angiogenesis and inflammation in the peritoneum. Blockade of interleukin (IL)-6 signaling rescued peritoneal transport function in Nx + salt mice. In cultured Met-5A, additional NaCl in the medium upregulated IL-6 as well as vascular endothelial growth factor-A, associated with increased expression and nuclear translocation of tonicity-responsive enhancer binding protein (TonEBP). Knockdown of TonEBP lowered the induction caused by high tonicity. Peritoneal TonEBP expression was higher in Nx + salt mice, while removal of high-salt diet lowered TonEBP level and improved peritoneal transport function.

CONCLUSIONS

Excessive dietary salt intake caused peritoneal membrane functional and structural changes under uremic status. TonEBP regulated hypertonicity-related inflammatory changes and might play a crucial role in high baseline peritoneal transport.

The glucose degradation product methylglyoxal induces immature angiogenesis in patients undergoing peritoneal dialysis

The accumulation of glucose degradation products (GDPs) can lead to tissue damage in patients with diabetes and those undergoing long-term peritoneal dialysis (PD). Angiogenesis is occasionally observed in the peritoneal membrane of patients undergoing PD, where it is associated with failure of ultrafiltration. To investigate the mechanism underlying the influence of angiogenesis on fluid absorption, we evaluated the effects of accumulation of the glucose degradation product methylglyoxal (MGO) on angiogenesis in vitro, and analyzed the association with angiogenesis in the peritoneal membrane. To this end, we measured the levels of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF)-BB in cultured endothelial and smooth muscle cells after administration of MGO. The expression of PDGF-BB mRNA and protein decreased significantly after exposure to MGO, while the expression of VEGF mRNA increased (both P < 0.01). The expression of PDGF-Rβ mRNA in cultured smooth muscle cells did not change after administration of MGO, although the expression of VEGF mRNA increased (P < 0.01). We also evaluated the associations between the number of capillary vessels, peritoneal function, and the degree of MGO deposition using peritoneum samples collected from patients undergoing PD. The number of immature capillary vessels was significantly associated with peritoneal dysfunction and the degree of MGO accumulation (both P < 0.01). In conclusion, MGO enhances the production of VEGF and suppresses the production of PDGF-BB, potentially leading to disturbance of angiogenesis in the peritoneal membrane. Accumulation of MGO in the peritoneum may cause immature angiogenesis and peritoneal dysfunction.

Peritoneal dialysis induces alterations in the transcriptome of peritoneal cells before detectible peritoneal functional changes

Long-term peritoneal dialysis (PD) is associated with functional and structural alterations of the peritoneal membrane. Inflammation may be the key moment, and, consequently, fibrosis may be the end result of chronic inflammatory reaction. The objective of the present study was to identify genes involved in peritoneal alterations during PD by comparing the transcriptome of peritoneal cells in patients with short- and long-term PD. Peritoneal effluent of the long dwell of patients with stable PD was centrifuged to obtain peritoneal cells. The gene expression profiles of peritoneal cells using microarray between patients with short- and long-term PD were compared. Based on microarray analysis, 31 genes for quantitative RT-PCR validation were chosen. A 4-h peritoneal equilibration test was performed on the day after the long dwell. Transport parameters and protein appearance rates were assessed. Genes involved in the immune system process, immune response, cell activation, and leukocyte and lymphocyte activation were found to be substantially upregulated in the long-term group. Quantitative RT-PCR validation showed higher expression of CD24, lymphocyte antigen 9 ( LY9), TNF factor receptor superfamily member 4 ( TNFRSF4), Ig associated-α ( CD79A), chemokine (C-C motif) receptor 7 ( CCR7), carcinoembryonic antigen-related cell adhesion molecule 1 ( CEACAM1), and IL-2 receptor-α ( IL2RA) in patients with long-term PD, with CD24 having the best discrimination ability between short- and long-term treatment. A relationship between CD24 expression and genes for collagen and matrix formation was shown. Activation of CD24 provoked by pseudohypoxia due to extremely high glucose concentrations in dialysis solutions might play the key role in the development of peritoneal membrane alterations.

Tamoxifen and bone morphogenic protein-7 modulate fibrosis and inflammation in the peritoneal fibrosis model developed in uremic rats

Background

Peritoneal fibrosis (PF) represents a long-term complication of peritoneal dialysis (PD), affecting peritoneal membrane (PM) integrity and function. Understanding the mechanisms underlying PF development in an uremic environment aiming alternative therapeutic strategies for treating this process is of great interest. The aim of this study was to analyze the effects of tamoxifen (TAM) and recombinant BMP7 (rBMP7) in an experimental model of PF developed in uremic rats.

Methods

To mimic the clinical situation of patients on long-term PD, a combo model, characterized by the combination of PF and CKD with severe uremia, was developed in Wistar rats. PF was induced by intraperitoneal (IP) injections of chlorhexidine gluconate (CG), and CKD was induced by an adenine-rich diet. Uremia was confirmed by severe hypertension, increased blood urea nitrogen (BUN> 120 mg/dL) and serum creatinine levels (> 2 mg/dL). Uremic rats with PF were treated with TAM (10 mg/Kg by gavage) or BMP7 (30 μg/Kg, IP). Animals were followed up for 30 days.

Results

CG administration in uremic rats induced a striking increase in PM thickness, neoangiogenesis, demonstrated by increased capillary density, and failure of ultrafiltration capacity. These morphological and functional changes were blocked by TAM or rBMP7 treatment. In parallel, TAM and rBMP7 significantly ameliorated the PM fibrotic response by reducing α-SMA, extracellular matrix proteins and TGF-ß expression. TAM or rBMP7 administration significantly inhibited peritoneal Smad3 expression in uremic rats with PF, prevented Smad3 phosphorylation, and induced a remarkable up-regulation of Smad7, an intracellular inhibitor of TGFβ/Smad signaling, contributing to a negative modulation of profibrotic genes. Both treatments were also effective in reducing local inflammation, possibly by upregulating IκB-α expression in the PM of uremic rats with PF. In vitro experiments using primary peritoneal fibroblasts activated by TGF-ß confirmed the capacity of TAM or rBMP7 in blocking inflammatory mediators, such as IL-1ß expression.

Conclusions

In conclusion, these findings indicate important roles of TGF-ß/Smad signaling in PF aggravated by uremia, providing data regarding potential therapeutic approaches with TAM or rBMP7 to block this process.

Electronic supplementary material

The online version of this article (10.1186/s10020-019-0110-5) contains supplementary material, which is available to authorized users.

Long-term peritoneal dialysis treatment provokes activation of genes related to adaptive immunity

Permanent irritation of the peritoneum during peritoneal dialysis (PD) treatment leads to local chronic inflammation and subsequently activation of processes driving fibrogenesis in the long-term. The aim of the study was to compare the peritoneal effluent transcriptome of 20 patients treated less and 13 patients treated more than 2 years using microarray analysis. An increased expression of genes associated with an immune response was observed in long-term treated patients with well preserved peritoneal function, when compared to patients treated less than 2 years. From 100 genes highly expressed in long-term patients, a significant up-regulation of six was found by RT-qPCR: LY9 (lymphocyte antigen 9), TNSFR4 (tumor necrosis factor receptor superfamily, member 4), CD 79A (CD79a molecule), CCR7 (chemokine C-C receptor 7), CEACAM1 (carcinoembryonic antigen-related cell adhesion molecule 1) and IL2RA (interleukin 2 receptor alpha chain). Furthermore, the effluent cell population was analysed. A positive relationship between the number of granulocytes and NK cells on one hand, and duration of PD treatment on the other, was shown. We conclude, that the mechanisms of adaptive immunity promoting T helper 2 cells response are activated in the long-term before functional alterations develop. It consequently might trigger the fibrosis promoting processes.

Protective effects and mechanisms of omega-3 polyunsaturated fatty acid on intestinal injury and macrophage polarization in peritoneal dialysis rats

AIM

This study was conducted to investigate the chronic injury of peritoneal glucose injection on the peritoneum and intestine and the protective effects of omega-3 polyunsaturated fatty acid (ω-3PUFA) during peritoneal dialysis (PD).

METHODS

Peritoneal dialysis animal models were established by intraperitoneal injection of 4.25% glucose for 28 days. Protein expression in ileum and peritoneum was measured by immunofloresence and immunohistochemistry. Protein expression in macrophages was measured by Western blot. Fibrosis was analyzed by Masson staining.

RESULTS

Peritoneal dialysis significantly increased the structural injury and decreased junction-related protein ZO-1 and occludin expression in ileum, the expression of proteins relating to the activation of M2 (Erg2, IRF4), but not M1 (CD38, IRF5) macrophages. PD significantly increased the expression of TGF-β1, VEGF and ALK5 protein in peritoneal tissues. PD significantly increased fibrosis (Masson staining) and the expression of fibroblast marker α-SMA in peritoneal tissues. Injection of macrophage clean reagent and ω-3PUFA significantly inhibited M2 activation, and decreased Masson staining, α-SMA, TGF-β1, VEGF and ALK5 protein expression in peritoneal tissues in PD treated rats. ω-3PUFA injection significantly decreased PD-induced injury in ileum and normalized the expression of ZO-1 and occludin in the ileum of PD rats.

CONCLUSION

Omega-3 fatty acids can provide a protective role on PD-induced peritoneal fibrosis and injury of the intestine.

HIF1A and VEGF regulate each other by competing endogenous RNA mechanism and involve in the pathogenesis of peritoneal fibrosis

BACKGROUND

Peritoneal fibrosis is a major intractable complication of long-term peritoneal dialysis, and would eventually lead to peritoneal ultrafiltration failure and the termination of peritoneal dialysis. Hypoxia-inducible factor 1-alpha (HIF1A) has been reported to regulate vascular endothelial growth factor (VEGF) and involves in peritoneal fibrosis, but the exact molecular regulation mechanism remains unknown.

METHODS

HIF1A and VEGF protein levels were measured in 42 peritoneal patients using enzyme linked immunosorbent assay. Bioinformatics, reverse transcription-polymerase chain reaction, correlation analysis, RNA interference, gene over-expression and luciferase assays were performed to clarify the competing endogenous RNA (ceRNA) regulation between HIF1A and VEGF.

RESULTS

Both HIF1A and VEGF levels were elevated in the peritoneal effluent of peritoneal dialysis patients with ultrafiltration problems, and were positively correlated with each other at protein level and mRNA level. Bioinformatics analysis identified 8 common targeted miRNAs for HIF1A and VEGF, including miR-17-5p, 20a, 20b, 93, 106a, 106b, 199a-5p and 203. MiR-17-5p was proved to be present in patients' peritoneal effluent and selected for further studies. HIF1A mRNA and VEGF mRNA could regulate each other, and miR-17-5p was required in the regulations. Down/up regulation of HIF1A mRNA and VEGF mRNA resulted in up/down regulation of miR-17-5p. Furthermore, down/up regulation of miR-17-5p was associated with up/down regulation of HIF1A mRNA and VEGF mRNA. Luciferase assay indicated that HIF1A and VEGF regulated each other through 3'UTR.

CONCLUSION

HIF1A and VEGF could regulate each other in peritoneal mesothelial cell in the mediation of miR-17-5p and 3'UTR, indicating HIF1A and VEGF might regulate each other through competing endogenous RNA mechanism in the development of peritoneal fibrosis.

Fibrosis of mesothelial cell-induced peritoneal implantation of ovarian cancer cells

Background

Peritoneal metastasis frequently occurs in patients with advanced ovarian cancer and is the main basis for a poor prognosis. The mechanism underlying preferential ovarian cancer spread to the peritoneum is not well understood.

Methods

Herein, we investigated the significance and mechanism underlying fibrosis of mesothelial cells promoting peritoneal implantation of ovarian cancer. We have assessed the mesothelial cell fibroblast transformation process in peritoneal tissues of omentum and fibrotic mesothelial cell release of chemokines to promote dissemination by scanning electron microscopy, ELISA, Western blot, and Transwell chamber assay.

Results

We showed that the fibrosis of mesothelial cells exists in the peritoneum of ovarian cancer patients with peritoneal metastasis. Fibrosis of the mesothelial cells was induced by TGF-β1, which upregulates the CXCL12–CXCR4 and CXCL16–CXCR6 axes of mesothelial cells.

Conclusion

CXCL12–CXCR4 and CXCL16–CXCR6 may be important signaling pathways closely involved in peritoneal metastasis of ovarian cancer that require further investigation. The findings may lead to developing alternative strategies aimed at preventing and treating the metastasis of ovarian cancer.

Aloe-Emodin Ameliorates Renal Fibrosis Via Inhibiting PI3K/Akt/mTOR Signaling Pathway In Vivo and In Vitro

Fibrosis is the major pathological feature of chronic kidney disease (CKD). Aloe-emodin (AE), one of the main active compounds in Rhubarb, is widely used for renal protection. However, mechanisms implied in the modulation of kidney fibrosis after AE treatment for CKD remain elusive. Here, we explored the protective effects of AE for renal fibrosis and the involved mechanisms in vivo and in vitro. The renal fibrosis mice model was established by unilateral ureteral obstruction (UUO). We found that AE administration significantly ameliorated UUO-induced impairment of kidney, evidenced by improved histopathological abnormalities, body weight, and abnormal renal function in mice model. Immunohistochemical staining showed that TGF-β1 and Fibronectin expressions were significantly decreased in UUO mice compared with sham group. Meanwhile, we found that AE suppressed the activation of the PI3K/Akt/mTOR pathway induced by TGF-β1 in vivo. AE improved cell survival and decreased the level of fibrosis-related proteins under TGF-β1-induced fibrosis in HK-2 cells as well as in vitro. Furthermore, both wortmannin, an inhibitor of PI3K, and short-hairpin RNAs of PI3K knockdown abrogated TGF-β1-induced phosphorylation of Akt and mTOR, and decreased the suppression of fibrosis. These findings indicated that AE alleviated fibrosis by inhibiting PI3K/Akt/mTOR pathway in vivo and in vitro, which may provide a potential therapeutic option for CKD.