The effect of statin on epithelial-mesenchymal transition in peritoneal mesothelial cells

Epithelial-mesenchymal Transition (EMT) and the Effect of Atorvastatin on it in ARPE-19 cells

Proliferative vitreoretinopathy (PVR) develops after an unsuccessful or complicated recovery from rhegmatogenous retinal detachment (RRD) surgery. Intraocular scar formation with the contribution of epithelial-mesenchymal transition (EMT) in RPE cells is prominent in the pathology of PVR. In the present study, the EMT process was experimentally induced in human retinal pigment epithelium (RPE; ARPE-19) cells, and the effect of atorvastatin on the process was studied. The mRNA and protein levels of mesenchymal markers actin alpha 2 (ACTA2) / alpha-smooth muscle actin (α-SMA) and fibronectin (FN), and epithelial markers occludin (OCLN) and zonula occludens-1 (ZO-1) were measured using quantitative real-time PCR (qRT-PCR) and western blot methods, respectively. In addition, α-SMA and FN were visualized using immunofluorescence staining. Cells were photographed under a phase contrast light microscope. Changes in the functionality of cells following the EMT process were studied using the IncuCyte scratch wound cell migration assay and the collagen cell invasion assay with confocal microscopy. The induction of EMT in ARPE-19 cells increased the expression of mesenchymal markers ACTA2/α-SMA and fibronectin and reduced the expression of epithelial marker OCLN both at mRNA and protein levels. The mRNA levels of ZO-1 were lower after EMT, as well. Increased levels of α-SMA and FN were confirmed by immunofluorescence staining. Atorvastatin further increased the mRNA levels of mesenchymal markers ACTA2 and FN as well as the protein levels of α-SMA and reduced the mRNA levels of epithelial markers OCLN and ZO-1 under the EMT process. EMT promoted wound closure and cell invasion into the 3D collagen matrix when compared to untreated control cells. These data present cellular changes upon the induction of the EMT process in ARPE-19 cells and the propensity of atorvastatin to complement the effect. More studies are needed to confirm the exact influence of the EMT process and atorvastatin treatment on the PVR development after RRD surgery.

Inhibition of EZH2 mitigates peritoneal fibrosis and lipid precipitation in peritoneal mesothelial cells mediated by klotho

BACKGROUND

Peritoneal fibrosis caused by long-term peritoneal dialysis (PD) is the main reason why patients withdraw from PD treatment. Lipid accumulation in the peritoneum was shown to participate in fibrosis, and klotho is a molecule involved in lipid metabolism. GSK343 (enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2) inhibitor) has been verified to inhibit epithelial mesenchymal transdifferentiation (EMT) and peritoneal fibrosis, but its related mechanism remains unclear. This study aimed to investigate whether lipid accumulation was involved in the effect of GSK343 and its related mechanism.

MATERIALS AND METHODS

First, the expression of EZH2, klotho and EMT indices in human peritoneal mesothelial cells (HMrSV5) incubated with high glucose (HG) levels was detected. After EZH2 was inhibited by GSK343, Western blot (WB), wound healing and Transwell assays were used to explore the effect of GSK343. EZH2 and klotho expression was also detected. Oil red O and Nile red staining and triglyceride (TG) detection kits were used to detect lipid accumulation. A rescue experiment with small interfering RNA specific for klotho (si-klotho) on the basis of GSK343 was also conducted to verify that GSK343 exerted its effect via klotho. In in vivo experiments, rats were administered GSK343, and the related index was assessed.

RESULTS

In our study, we revealed that the expression of EZH2 was significantly upregulated and klotho was significantly downregulated in HMrSV5 cells induced by high glucose. With the aid of GSK343, we found that lipid deposition caused by HG was significantly decreased. In addition, EMT and fibrosis were also significantly alleviated. Moreover, GSK343 could also restore the downregulation of klotho. To further verify whether klotho mediated the effect of EZH2, a rescue experiment with si-klotho was also conducted. The results showed that si-klotho could counteract the protective effect of GSK343 on high glucose-induced lipid accumulation and fibrosis. In vivo experiments also revealed that GSK343 could relieve peritoneal fibrosis, lipid deposition and EMT by mitigating EZH2 and restoring klotho expression.

CONCLUSIONS

Combining these findings, we found that EZH2 regulated lipid deposition, peritoneal fibrosis, and EMT mediated by klotho. To our knowledge, this is the first study to demonstrate the effect of the EZH2-klotho interaction on peritoneal fibrosis. Hence, EZH2 and klotho could act as potential targets for the treatment of peritoneal fibrosis.

Anti-fibrotic effects of statin drugs: a review of evidence and mechanisms

Fibrosis is a pathological repair process common among organs, that responds to damage by replacement of tissue with non-functional connective tissue. Despite the widespread prevalence of tissue fibrosis, manifesting in numerous disease states across myriad organs, therapeutic modalities to prevent or alleviate fibrosis are severely lacking in quantity and efficacy. Alongside development of new drugs, repurposing of existing drugs may be a complementary strategy to elect anti-fibrotic compounds for pharmacologic treatment of tissue fibrosis. Drug repurposing can provide key advantages to de novo drug discovery, harnessing the benefits of previously elucidated mechanisms of action and already existing pharmacokinetic profiles. One class of drugs a wealth of clinical data and extensively studied safety profiles is the statins, a class of antilipidemic drugs widely prescribed for hypercholesterolemia. In addition to these widely utilized lipid-lowering effects, increasing data from cellular, pre-clinical mammalian, and clinical human studies have also demonstrated that statins are able to alleviate tissue fibrosis originating from a variety of pathological insults via lesser-studied, pleiotropic effects of these drugs. Here we review literature demonstrating evidence for direct effects of statins antagonistic to fibrosis, as well as much of the available mechanistic data underlying these effects. A more complete understanding of the anti-fibrotic effects of statins may enable a clearer picture of their anti-fibrotic potential for various clinical indications. Additionally, more lucid comprehension of the mechanisms by which statins exert anti-fibrotic effects may aid in development of novel therapeutic agents that target similar pathways but with greater specificity or efficacy.

Atorvastatin facilitates chemotherapy effects in metastatic triple-negative breast cancer

BACKGROUND

Metastatic triple-negative breast cancer (mTNBC) is treated mainly with chemotherapy. However, resistance frequently occurs as tumours enter dormancy. Statins have been suggested as effective against cancer but as they prolong and promote dormancy, it is an open question of whether the concomitant use would interfere with chemotherapy in primary and mTNBC. We examined this question in animal models and clinical correlations.

METHODS

We used a xenograft model of spontaneous metastasis to the liver from an ectopic tumour employing a mTNBC cell line. Atorvastatin was provided to sensitise metastatic cells, followed by chemotherapy. The effects of statin usage on outcomes in women with metastatic breast cancer was assessed respectively by querying a database of those diagnosed from 1999 to 2019.

RESULTS

Atorvastatin had limited influence on tumour growth or chemotherapy effects in ectopic primary tumours. Interestingly, atorvastatin was additive with doxorubicin (but not paclitaxel) when targeting liver metastases. E-cadherin-expressing, dormant, breast cancer cells were resistant to the use of either statins or chemotherapy as compared to wild-type cells; however, the combination of both did lead to increased cell death. Although prospective randomised studies are needed for validation, our retrospective clinical analysis suggested that patients on statin treatment could experience prolonged dormancy and overall survival; still once the tumour recurred progression was not affected by statin use.

CONCLUSION

Atorvastatin could be used during adjuvant chemotherapy and also in conjunction with metastatic chemotherapy to reduce mTNBC cancer progression. These preclinical data establish a rationale for the development of randomised studies.

Effect of aquaporin 1 on mouse peritoneal mesothelial cells after a long-term peritoneal dialysis

Aquaporin 1 (AQP1) is one member of the aquaporin family, also the deeply studied one. It is widely located on the endothelial cells, but the effect of AQP1 on the peritoneal mesothelial cells (PMCs) after long-term peritoneal dialysis (PD) has not been reported before. We divided normal mice into two groups, control group and dialysis group, to confirm the fibrotic changes and expression of APQ1 on peritoneal mesothelial cells. Then we assigned normal mice and AQP1 knockout mice into four groups: Control group, normal dialysis group, AQP1 knockout control group and AQP1 knockout dialysis group. The two dialysis groups received 4.25% glucose dialysis for 28 days. We found that mice in both dialysis groups showed peritoneal fibrotic changes, which were most severe in the AQP1 knockout dialysis group; the peritoneal thickness in the AQP1 knockout dialysis group was also thicker than that in the dialysis group (P < .05). We used electron microscopy to detect ultrastructural changes and observed changes in microvilli and vacuolar degeneration in mesothelial cells from all groups except the control group. The basement membranes were damaged in the AQP1 knockout dialysis group, and peritoneal mesothelial cells were disrupted and detached in this group. Together our findings indicate that AQP1 plays an important role in maintaining the physiological functions of peritoneal mesothelial cells, and AQP1 can protect mesothelial cells during dialysis.

IL-17A as a Potential Therapeutic Target for Patients on Peritoneal Dialysis

Chronic kidney disease (CKD) is a health problem reaching epidemic proportions. There is no cure for CKD, and patients may progress to end-stage renal disease (ESRD). Peritoneal dialysis (PD) is a current replacement therapy option for ESRD patients until renal transplantation can be achieved. One important problem in long-term PD patients is peritoneal membrane failure. The mechanisms involved in peritoneal damage include activation of the inflammatory and immune responses, associated with submesothelial immune infiltrates, angiogenesis, loss of the mesothelial layer due to cell death and mesothelial to mesenchymal transition, and collagen accumulation in the submesothelial compact zone. These processes lead to fibrosis and loss of peritoneal membrane function. Peritoneal inflammation and membrane failure are strongly associated with additional problems in PD patients, mainly with a very high risk of cardiovascular disease. Among the inflammatory mediators involved in peritoneal damage, cytokine IL-17A has recently been proposed as a potential therapeutic target for chronic inflammatory diseases, including CKD. Although IL-17A is the hallmark cytokine of Th17 immune cells, many other cells can also produce or secrete IL-17A. In the peritoneum of PD patients, IL-17A-secreting cells comprise Th17 cells, γδ T cells, mast cells, and neutrophils. Experimental studies demonstrated that IL-17A blockade ameliorated peritoneal damage caused by exposure to PD fluids. This article provides a comprehensive review of recent advances on the role of IL-17A in peritoneal membrane injury during PD and other PD-associated complications.

Increased miR-7641 Levels in Peritoneal Hyalinizing Vasculopathy in Long-Term Peritoneal Dialysis Patients

Peritoneal hyalinizing vasculopathy (PHV) represents the cornerstone of long-term peritoneal dialysis (PD), and especially characterizes patients associated with encapsulating peritoneal sclerosis. However, the mechanisms of PHV development remain unknown. A cross sectional study was performed in 100 non-selected peritoneal biopsies of PD patients. Clinical data were collected and lesions were evaluated by immunohistochemistry. In selected biopsies a microRNA (miRNA)-sequencing analysis was performed. Only fifteen patients (15%) showed PHV at different degrees. PHV prevalence was significantly lower among patients using PD fluids containing low glucose degradation products (GDP) (5.9% vs. 24.5%), angiotensin converting enzyme inhibitors (ACEIs) (7.5% vs. 23.4%), statins (6.5% vs. 22.6%) or presenting residual renal function, suggesting the existence of several PHV protective factors. Peritoneal biopsies from PHV samples showed loss of endothelial markers and induction of mesenchymal proteins, associated with collagen IV accumulation and wide reduplication of the basement membrane. Moreover, co-expression of endothelial and mesenchymal markers, as well as TGF-β1/Smad3 signaling activation were found in PHV biopsies. These findings suggest that an endothelial-to-mesenchymal transition (EndMT) process was taking place. Additionally, significantly higher levels of miR-7641 were observed in severe PHV compared to non-PHV peritoneal biopsies. Peritoneal damage by GDPs induce miRNA deregulation and an EndMT process in submesothelial vessels, which could contribute to collagen IV accumulation and PHV.

Productive Cross-Talk with the Microenvironment: A Critical Step in Ovarian Cancer Metastasis

Most ovarian cancer patients present with disseminated disease at the time of their diagnosis, which is one of the main reasons for their poor prognosis. Metastasis is a multi-step process and a clear understanding of the mechanism of regulation of these steps remains elusive. Productive reciprocal interactions between the metastasizing ovarian cancer cells and the microenvironment of the metastatic site or the tumor microenvironment play an important role in the successful establishment of metastasis. Much progress has been made in the recent past in our understanding of such interactions and the role of the cellular and acellular components of the microenvironment in establishing the metastatic tumors. This review will outline the role of the microenvironmental components of the ovarian cancer metastatic niche and their role in helping establish the metastatic tumors. Special emphasis will be given to the mesothelial cells, which are the first cells encountered by the cancer cells at the site of metastasis.

Simvastatin Attenuates Hippocampal MMP-9 Expression in the Streptozotocin-Induced Cognitive Impairment

BACKGROUND

Matrix metalloproteinase-9 (MMP-9) expression has been implicated in molecular mechanisms of neurodegenerative disorders, and its abnormal level has been reported in Alzheimer’s disease (AD). Some protective mechanisms of statins against neurodegeneration might be mediated by the inhibition of MMP-9 expression. Here, we investigated the effect of simvastatin on the hippocampal MMP-9 expression in the context of AD.

METHODS

We examined the influence of three-week simvastatin (5 mg/kg) administration on hippocampal MMP-9 expression in a rat model of cognitive decline induced by streptozotocin (STZ). Spatial long-term memory and MMP-9 expression were assessed by Morris water maze (MWM) test and quantitative polymerase chain reaction, respectively.

RESULTS

The results showed a decline in the learning and memory in STZ group when compared with the control group. The MMP-9 up-regulated (1.41 ± 0.2 vs. 0.980 ± 0.02, p < 0.05), and cresyl violet staining showed hippocampal cell damage in STZ group compared with the control group. Simvastatin prevented the up-regulation of MMP-9 (1.05 ± 0.05 vs. 1.41 ± 0.2, p < 0.05), improved spatial memory impairment and attenuated hippocampal cell damage. Furthermore, we found a negative correlation (r = 0.77) between MMP-9 expression and cognitive function.

CONCLUSION

Our findings suggest that the neuroprotective influence of simvastatin in battle to cognitive impairment is mediated in part by the modulation of MMP-9 expression. The reduction of MMP-9 expression in simvastatin-treated animals is in correlation with the improvement of cognitive functions. Understanding the protective mechanism of simvastatin will shed light on more efficient therapeutic modalities in AD.

Neoadjuvant chemotherapy with gemcitabine-based regimens improves the prognosis of node positive resectable pancreatic head cancer

The effectiveness of preoperative (neoadjuvant) chemotherapy (NAC) for resectable pancreatic ductal adenocarcinoma (PDAC) remains unclear. The present study retrospectively evaluated the efficacy of NAC with gemcitabine (GEM)-based regimens or GEM monotherapy for resectable PDAC. Between 2006 and 2015, NAC with GEM was performed in 52 cases (head 31, and body and tail 21) and compared with 34 resection-only cases serving as controls (head 20, and body and tail 14). According to the Response Evaluation Criteria In Solid Tumors guidelines, the treatment effect was a partial response in 5 cases, stable disease in 45 cases, and progressive disease in 2 cases. Maximum standardized uptake values and carbohydrate antigen (CA19-9) values were significantly reduced after preoperative chemotherapy. Using the Evans grading system, the treatment effect was grade I in 31 patients, grade IIa in 8, and grade IIb in 3 cases. There were significant differences in the overall survival rate between the NAC and control groups, only in the patients with node-positive pancreatic head cancer. Significantly higher CA19-9 values in peripheral blood and higher lymph node metastasis and plexus invasion rates were observed in early-recurring cases within a year. The preoperative CA 19-9 cutoff value as an early recurrence risk factor was calculated as 30 U/ml in the NAC group and 88 U/ml in the control group. NAC with GEM prolonged survival in patients with node-positive pancreatic head cancer. High CA19-9 values before operation, lymph node metastases and plexus invasion were risk factors for early tumor recurrence after surgery. Preoperative chemotherapy would be necessary for resectable pancreatic head cancer as lymph node metastasis was observed in >60% with resectable PDAC. Moreover, if normalization of CA19-9 values is not achieved with NAC, extension of preoperative chemotherapy should be considered as for borderline resectable PDAC cases.

Senescence-related deterioration of intercellular junctions in the peritoneal mesothelium promotes the transmesothelial invasion of ovarian cancer cells

Mechanisms of transmesothelial invasion of ovarian cancer are still poorly understood. Here we examined whether this phenomenon may be determined by an expression of intercellular junctions in peritoneal mesothelial cells (PMCs). Analysis of ovarian tumors showed that cancer cells are localized below an intact layer of PMCs. The PMCs located near the invaded cancer cells displayed low expression of connexin 43, E-cadherin, occludin, and desmoglein, as well as expressed SA-β-Gal, a marker of senescence. Experiments in vitro showed that senescent PMCs exhibited decreased levels of the four tested intercellular junctions, and that the invasion of ovarian cancer cells through the PMCs increased proportionally to the admixture of senescent cells. Intervention studies showed that the expression of connexin 43, E-cadherin, occludin, and desmoglein in senescent PMCs could be restored upon the blockade of p38 MAPK, NF-κB, AKT, JNK, HGF, and TGF-β1. When these molecules were neutralized, the efficiency of the transmesothelial cancer cell invasion was diminished. Collectively, our findings show that the integrity of the peritoneal mesothelium, which is determined by the expression of junctional proteins, is critical for the invasion of ovarian cancer. They also indicate a mechanism by which senescent PMCs may promote the invasive potential of cancer cells.

Rapamycin inhibits peritoneal fibrosis by modifying lipid homeostasis in the peritoneum

Peritoneal fibrosis (PF) is characterized by progressive accumulation of extracellular matrix (ECM) components in the peritoneum under high glucose conditions. Rapamycin has previously been shown to inhibit ECM accumulation of peritoneal mesothelial cells (PMCs) and prevent PF. Here we explored the undefined mechanisms by which rapamycin inhibits ECM accumulation of PMCs. We used high-glucose peritoneal dialysis solution (PDS) in a mouse peritoneal dialysis model to induce in vivo PF and in human PMCs in vitro to stimulate ECM accumulation. The mice that received chronic PDS infusions showed typical features of PF, including markedly increased peritoneal thickness, excessive matrix deposition, increased peritoneal permeability, and higher expressions of α-smooth muscle actin and collagen I. Rapamycin significantly ameliorated these pathological changes. There was a parallel decrease in lipid accumulation in the peritoneum of rapamycin-treated mice. Rapamycin significantly inhibited high-glucose PDS-induced ECM accumulation and reduced the lipid droplet in human PMCs in the presence of PDS. The effects of rapamycin on intracellular lipid metabolism correlated with a series of steps in lipid homeostasis; namely, a decrease in low density lipoprotein receptor-mediated lipid influx, which was mediated through the downregulation of sterol regulatory element-binding protein-2 (SREBP-2) and SREBP cleavage-activating protein (SCAP), and an increase in adenosine triphosphate-binding cassette transporter A1-mediated lipid efflux, which was mediated through the upregulation of the liver X receptor α and peroxisome proliferator-activated receptor α. We conclude that rapamycin shows a clear protective effect on high-glucose PDS-induced PF by improving the disruption of intracellular lipid homeostasis.

Lipophilic statins antagonistically alter the major epithelial-to-mesenchymal transition signaling pathways in breast cancer stem-like cells via inhibition of the mevalonate pathway

Resistance to therapies, recurrence, and metastasis remain challenging issues for breast cancer patients, particularly for triple-negative and breast cancer stem cells. The activation of the epithelial-to-mesenchymal transition (EMT) plays an indispensable role in the poor prognosis of those types. The accumulating proofs indicated that the mevalonate pathway crucially mediates a poor prognosis. Here, the effects of lipophilic 3-hydroxy-3-methyl-glutaryl-coenzyme A inhibitors, atorvastatin, lovastatin, and simvastatin, were investigated on expression and function of a selected profile of EMT-related genes in breast cancer stem-like cells. A nontoxic dose of statins (5 μM for 4 days) significantly (P < 0.05 and >2-fold change) altered expression of 50 of 71 studied genes with a shared cluster of 37 genes that are coding chief operator of signaling pathways in Hippo, Notch, Wnt, proliferation, invasion, angiogenesis, and cell death. They also significantly decreased the levels of Yap/Taz proteins and shifted the expression of vimentin/E-cadherin in favor of induction of differentiation. Statins significantly chemosensitized the treated cells to doxorubicin and also reduced in vitro migration of the cells. Whereas lovastatin and simvastatin significantly decreased the expression of CD44, atorvastatin drastically increased CD24 and caused more wide-ranging impacts. In summary, the statins hold back the process of EMT by the antagonizing of EMT-promoting pathways. High degree of overlapping findings is supportive of the central role of the mevalonate pathway in cancer stem-like cells, but further studies are required to find the optimized chemical structure for the maximum abrogation of orchestrated EMT pathways.

CtBP promotes metastasis of breast cancer through repressing cholesterol and activating TGF-β signaling

Metastasis is the process through which the primary cancer cells spread beyond the primary tumor and disseminate to other organs. Most cancer patients die of metastatic disease. EMT is proposed to be the initial event associated with cancer metastasis and how it occurred is still a mystery. CtBP is known as a co-repressor abundantly expressed in many types of cancer and regulates genes involved in cancer initiation, progression, and metastasis. We found that CtBP regulates intracellular cholesterol homeostasis in breast cancer cells by forming a complex with ZEB1 and transcriptionally repressing SREBF2 expression. Importantly, CtBP repression of intracellular cholesterol abundance leads to increased EMT and cell migration. The reason is that cholesterol negatively regulates the stability of TGF-β receptors on the cell membrane. Interestingly, TGF-β is also capable of reducing intracellular cholesterol relying on the increased recruitment of ZEB1 and CtBP complex to SREBF2 promoter. Thus, we propose a feedback loop formed by CtBP, cholesterol, and TGF-β signaling pathway, through which TGF-β triggers the cascade that mobilizes the cancer cells for metastasis. Consistently, the intravenous injection of breast cancer cells with ectopically CtBP expression show increased lung metastasis depending on the reduction of intracellular cholesterol. Finally, we analyzed the public breast cancer datasets and found that CtBP expression negatively correlates with SREBF2 and HMGCR expressions. High expression of CtBP and low expression of SREBF2 and HMGCR significantly correlates with high EMT of the primary tumors.

Peritoneal Membrane Preservation

Peritoneal dialysis (PD) is a successfully used method for renal replacement therapy. However, long-term PD may be associated with peritoneal fibrosis and ultrafiltration failure. The key factors linked to their appearance are repeated episodes of inflammation associated with peritonitis and long-term exposure to bioincompatible PD fluids. Different strategies have been proposed to preserve the peritoneal membrane. This article reviews the functional and structural alterations related to PD and strategies whereby we may prevent them to preserve the peritoneal membrane. The use of new, more biocompatible, PD solutions is promising, although further morphologic studies in patients using these solutions are needed. Blockade of the renin-angiotensin-aldosterone system appears to be efficacious and strongly should be considered. Other agents have been proven in experimental studies, but most of them have not yet been tested appropriately in human beings.

Inflammation and Peritoneal Dialysis

Inflammation is one of the well-recognized nontraditional risk factors that contributes to the excessive cardiovascular mortality in peritoneal dialysis (PD) patients. Serum C-reactive protein and interleukin-6 levels are common surrogate markers used to measure inflammatory burden and predict adverse clinical outcomes in PD patients. Causes of inflammation are complex and can be categorized into factors related to a decrease in renal function and factors related to dialysis. They interact with each other and finally result in systemic and intraperitoneal inflammation. This review discusses the various causes and clinical implications of inflammation in PD patients. More importantly, potential therapeutic options that target the underlying pathogenic mechanisms are explored.

Simvastatin treatment boosts benefits of apoptotic cell infusion in murine lung fibrosis

A single early-phase infusion of apoptotic cells can inhibit bleomycin-induced lung inflammation and fibrosis; however, it is unknown whether these effects can be enhanced with additional infusions and/or statin treatment. Here, we investigated whether an increased frequency of apoptotic cell injection, with or without efferocytosis enhancer simvastatin, facilitates therapeutic efficacy. An additional injection of apoptotic cells during the intermediate phase (7 days post-bleomycin treatment) or simvastatin administration alone on days 7–13 post-treatment did not promote anti-fibrotic responses beyond those induced by a single early apoptotic cell infusion alone. Additional administration of apoptotic cells with simvastatin further enhanced the efferocytic ability of alveolar macrophages and PPARγ activity, and induced hepatocyte growth factor and interleukin-10 expression, in alveolar macrophages and lung tissue. Additional administration of apoptotic cells with simvastatin also reduced mRNA expression of bleomycin-induced epithelial-mesenchymal transition (EMT) markers in isolated alveolar type II epithelial cells, fibrotic markers in fibroblasts, and hydroxyproline in lung tissue. Enhanced anti-EMT and anti-fibrotic efficacy was confirmed by immunofluorescence and trichrome staining of lung tissue. This suggests that additional administration of apoptotic cells with simvastatin during the intermediate phase of bleomycin-induced lung fibrosis may boost the anti-fibrotic properties of early apoptotic cell infusion.

Neoadjuvant chemotherapy for pancreatic cancer: Effects on cancer tissue and novel perspectives

Chemotherapy for pancreatic cancer has diversified following the addition of more treatment regimens; however, in spite of this, pancreatic cancer remains a fatal disease. Preoperative (neoadjuvant) chemotherapy (NAC) or neoadjuvant chemoradiation therapy (NACRT) has been developed and implemented. For patients with borderline resectable pancreatic cancer (BRPC) and locally advanced pancreatic cancer (LAPC), a number of clinical trials have been conducted; NACRT was demonstrated to improve resectability, R0 resection rate, overall survival rate, disease-free survival rate and even an LAPC and BRPC survival advantage over NAC. However, from the knowledge obtained from resected specimens following preoperative treatment, residual pancreatic cancer tissues following NAC are rich in chemoresistant cancer stem-like cells and epithelial-mesenchymal transition (EMT) markers. Conversely, metformin, angiotensin receptor blocker, statins and low-dose paclitaxel are well-known as drugs that inhibit EMT, which is associated with cancer stem cell-like characteristics. Although clinical effectiveness is unlikely to be achieved using one of these as an anticancer agent, it is reasonable to use these drugs for patients with comorbidities in the treatment of pancreatic cancer. Furthermore, gemcitabine (GEM) affects antitumor immunity by stimulating the expression of major histocompatibility complex class I-related chain A on the surface of cancer cells to enhance the cytotoxicity of natural killer cells. Considering EMT and antitumor immunity, there is a possibility that GEM and nanoparticle albumin-bound paclitaxel therapy is the most suitable regimen for treating pancreatic cancer. However, even as preoperative treatment progresses, R0 resection is the most important factor for the long-term survival of pancreatic cancer patients.

Cigarette smoke attenuates phagocytic ability of macrophages through down-regulating Milk fat globule-EGF factor 8 (MFG-E8) expressions

Chronic obstructive pulmonary disease (COPD) is one of the most common inflammatory diseases resulting from habitual smoking. Impaired clearance of apoptotic cell by airway macrophages contributes to lung inflammation. Milk fat globule-EGF factor 8 (MFG-E8), as a link between apoptotic cells and phagocytes, facilitates clearance of apoptotic cells and attenuates inflammation. We sought to investigate altered expression and potential role of MFG-E8 in COPD. In this study, apoptosis was increased and the level of MFG-E8 was decreased while HMGB1 expression was increased in lung tissues of CS-exposed mice. Compared with CS-exposed WT mice, more apoptotic cells were accumulated in lung tissues of CS-exposed MFG-E8 deficiency mice. Exposure of a range of macrophages to cigarette smoke extract (CSE) resulted in decreased MFG-E8 expression. Administration of rmMFG-E8 ameliorated phagocytic ability of RAW264.7 cells and suppressed inflammatory response induced by CS-exposure. 10% CSE stimulation suppressed Rac1 membrane localization in RAW264.7 cells which was restored by administration of rmMFG-E8. MFG-E8 deficiency diminished uptake of apoptotic thymocytes by peritoneal macrophages upon CSE exposure. Overall, the findings in current work provide a novel target for diagnosing and treating COPD.

Preserving the peritoneal membrane in long-term peritoneal dialysis patients

WHAT IS KNOWN AND OBJECTIVE

Peritoneal dialysis (PD) has been widely used by patients with end-stage renal disease. However, chronic exposure of the peritoneal membrane to bioincompatible PD solutions, and peritonitis and uraemia during long-term dialysis result in peritoneal membrane injury and thereby contribute to membrane changes, ultrafiltration (UF) failure, inadequate dialysis and technical failure. Therefore, preserving the peritoneal membrane is important to maintain the efficacy of PD. This article reviews the current literature on therapeutic agents for preserving the peritoneal membrane.

METHODS

A literature search of PubMed was conducted using the search terms peritoneal fibrosis, peritoneal sclerosis, membrane, integrity, preserve, therapy and peritoneal dialysis, but not including peritonitis. Published clinical trials, in vitro studies, experimental trials in animal models, meta-analyses and review articles were identified and reviewed for relevance.

RESULTS AND DISCUSSION

We focus on understanding how factors cause peritoneal membrane changes, the characteristics and mechanisms of peritoneal membrane changes in patients undergoing PD and the types of therapeutic agents for peritoneal membrane preservation. There have been many investigations into the preservation of the peritoneal membrane, including PD solution improvement, the inhibition of cytokine and growth factor expression using renin-angiotensin-aldosterone system (RAAS) blockade, glycosaminoglycans (GAGs), L-carnitine and taurine additives. In addition, there are potential future therapeutic agents that are still in experimental investigations.

WHAT IS NEW AND CONCLUSION

The efficacy of many of the therapeutic agents is uncertain because there are insufficient good-quality clinical studies. Overall membrane preservation and patient survival remain unproven in using more biocompatible PD solutions. With RAAS blockade, results are still inconclusive, as many of the clinical studies were retrospective. With GAGs, L-carnitine and taurine additives, there is no sufficiently long follow-up clinical study with a large sample size to support its efficacy. Therefore, better quality clinical studies within this area should be performed.