Adipose tissue macrophage dysfunction is associated with a breach of vascular integrity in NASH.

BACKGROUND & AIMS: In non-alcoholic fatty liver disease (NAFLD), monocytes infiltrate visceral adipose tissue promoting local and hepatic inflammation. However, it remains unclear what drives inflammation and how the immune landscape in adipose tissue differs across the NAFLD severity spectrum. We aimed to assess adipose tissue macrophage (ATM) heterogeneity in a NAFLD cohort. METHODS: Visceral adipose tissue macrophages from lean and obese patients, stratified by NAFLD phenotypes, underwent single-cell RNA sequencing. Adipose tissue vascular integrity and breaching was assessed on a protein level via immunohistochemistry and immunofluorescence to determine targets of interest. RESULTS: We discovered multiple ATM populations, including resident vasculature-associated macrophages (ResVAMs) and distinct metabolically active macrophages (MMacs). Using trajectory analysis, we show that ResVAMs and MMacs are replenished by a common transitional macrophage (TransMac) subtype and that, during NASH, MMacs are not effectively replenished by TransMac precursors. We postulate an accessory role for MMacs and ResVAMs in protecting the adipose tissue vascular barrier, since they both interact with endothelial cells and localize around the vasculature. However, across the NAFLD severity spectrum, alterations occur in these subsets that parallel an adipose tissue vasculature breach characterized by albumin extravasation into the perivascular tissue. CONCLUSIONS: NAFLD-related macrophage dysfunction coincides with a loss of adipose tissue vascular integrity, providing a plausible mechanism by which tissue inflammation is perpetuated in adipose tissue and downstream in the liver. IMPACT AND IMPLICATIONS: Our study describes for the first time the myeloid cell landscape in human visceral adipose tissue at single-cell level within a cohort of well-characterized patients with non-alcoholic fatty liver disease. We report unique non-alcoholic steatohepatitis-specific transcriptional changes within metabolically active macrophages (MMacs) and resident vasculature-associated macrophages (ResVAMs) and we demonstrate their spatial location surrounding the vasculature. These dysfunctional transcriptional macrophage states coincided with the loss of adipose tissue vascular integrity, providing a plausible mechanism by which tissue inflammation is perpetuated in adipose tissue and downstream in the liver. Our study provides a theoretical basis for new therapeutic strategies to be directed towards reinstating the endogenous metabolic, homeostatic and cytoprotective functions of ResVAMs and MMacs, including their role in protecting vascular integrity.

Biomimetic superabsorbent hydrogel acts as a gut protective dynamic exoskeleton improving metabolic parameters and expanding A. muciniphila.

The rising prevalence of obesity and metabolic disorders worldwide highlights the urgent need to find new long-term and clinically meaningful weight-loss therapies. Here, we evaluate the therapeutic potential and the mechanism of action of a biomimetic cellulose-based oral superabsorbent hydrogel (OSH). Treatment with OSH exerts effects on intestinal tissue and gut microbiota composition, functioning like a protective dynamic exoskeleton. It protects from gut barrier permeability disruption and induces rapid and consistent changes in the gut microbiota composition, specifically fostering Akkermansia muciniphila expansion. The mechanobiological, physical, and chemical structures of the gel are required for A. muciniphila growth. OSH treatment induces weight loss and reduces fat accumulation, in both preventative and therapeutic settings. OSH usage also prevents liver steatosis, immune infiltration, and fibrosis, limiting the progression of non-alcoholic fatty liver disease. Our work shows the potential of using OSH as a non-systemic mechanobiological approach to treat metabolic syndrome and its comorbidities.

The gut vascular barrier: a new player in the gut-liver-brain axis.

The intestinal barrier protects our body from external insults through specialized cells organized in a multilayered structure that evolved in symbiosis with the resident microbiota. A breach in the outer mucus and epithelium can be transmitted to the inner gut vascular barrier (GVB), leading to systemic dissemination of microbes or microbe-derived molecules. Several extraintestinal pathologies have been linked to gut microbiota dysbiosis that causes GVB leakage in their early phases. The consequent spreading of inflammatory stimuli to distant organs could be driven by later vascular barrier disruption at different sites, suggesting an interplay between anatomical barriers across the body. Thus, targeting the intestinal barrier holds promise for the prevention and/or therapy of several intestinal, metabolic, and neurological disorders.

Gut-Liver Axis in Nonalcoholic Fatty Liver Disease: the Impact of the Metagenome, End Products, and the Epithelial and Vascular Barriers.

Nonalcoholic fatty liver disease (NAFLD) is a systemic, dynamic, heterogeneous, and multiaxis entity, the pathogenesis of which is still uncertain. The gut-liver axis is regulated and stabilized by a complex network encompassing a metabolic, immune, and neuroendocrine cross-talk between the gut, the microbiota, and the liver. Changes in the gut-liver axis affect the metabolism of lipids and carbohydrates in the hepatocytes, and they impact the balance of inflammatory mediators and cause metabolic deregulation, promoting NAFLD and its progression to nonalcoholic steatohepatitis. Moreover, the microbiota and its metabolites can play direct and indirect roles in gut barrier function and fibrosis development. In this review, we will highlight findings from the recent literature focusing on the gut-liver axis and its relation to NAFLD. Finally, we will discuss the impact of technical issues, design bias, and other limitations on current knowledge of the gut microbiota in the context of NAFLD.

Gut vascular barrier impairment leads to intestinal bacteria dissemination and colorectal cancer metastasis to liver.

Metastasis is facilitated by the formation of a "premetastatic niche," which is fostered by primary tumor-derived factors. Colorectal cancer (CRC) metastasizes mainly to the liver. We show that the premetastatic niche in the liver is induced by bacteria dissemination from primary CRC. We report that tumor-resident bacteria Escherichia coli disrupt the gut vascular barrier (GVB), an anatomical structure controlling bacterial dissemination along the gut-liver axis, depending on the virulence regulator VirF. Upon GVB impairment, bacteria disseminate to the liver, boost the formation of a premetastatic niche, and favor the recruitment of metastatic cells. In training and validation cohorts of CRC patients, we find that the increased levels of PV-1, a marker of impaired GVB, is associated with liver bacteria dissemination and metachronous distant metastases. Thus, PV-1 is a prognostic marker for CRC distant recurrence and vascular impairment, leading to liver metastases.

Microbiota-driven gut vascular barrier disruption is a prerequisite for non-alcoholic steatohepatitis development.

BACKGROUND & AIMS: Fatty liver disease, including non-alcoholic fatty liver (NAFLD) and steatohepatitis (NASH), has been associated with increased intestinal barrier permeability and translocation of bacteria or bacterial products into the blood circulation. In this study, we aimed to unravel the role of both intestinal barrier integrity and microbiota in NAFLD/NASH development. METHODS: C57BL/6J mice were fed with high-fat diet (HFD) or methionine-choline-deficient diet for 1 week or longer to recapitulate aspects of NASH (steatosis, inflammation, insulin resistance). Genetic and pharmacological strategies were then used to modulate intestinal barrier integrity. RESULTS: We show that disruption of the intestinal epithelial barrier and gut vascular barrier (GVB) are early events in NASH pathogenesis. Mice fed HFD for only 1 week undergo a diet-induced dysbiosis that drives GVB damage and bacterial translocation into the liver. Fecal microbiota transplantation from HFD-fed mice into specific pathogen-free recipients induces GVB damage and epididymal adipose tissue enlargement. GVB disruption depends on interference with the WNT/ß-catenin signaling pathway, as shown by genetic intervention driving ß-catenin activation only in endothelial cells, preventing GVB disruption and NASH development. The bile acid analogue and farnesoid X receptor agonist obeticholic acid (OCA) drives ß-catenin activation in endothelial cells. Accordingly, pharmacologic intervention with OCA protects against GVB disruption, both as a preventive and therapeutic agent. Importantly, we found upregulation of the GVB leakage marker in the colon of patients with NASH. CONCLUSIONS: We have identified a new player in NASH development, the GVB, whose damage leads to bacteria or bacterial product translocation into the blood circulation. Treatment aimed at restoring ß-catenin activation in endothelial cells, such as administration of OCA, protects against GVB damage and NASH development. LAY SUMMARY: The incidence of fatty liver disease is reaching epidemic levels in the USA, with more than 30% of adults having NAFLD (non-alcoholic fatty liver disease), which can progress to more severe non-alcoholic steatohepatitis (NASH). Herein, we show that disruption of the intestinal epithelial barrier and gut vascular barrier are early events in the development of NASH. We show that the drug obeticholic acid protects against barrier disruption and thereby prevents the development of NASH, providing further evidence for its use in the prevention or treatment of NASH.

MEF2B Instructs Germinal Center Development and Acts as an Oncogene in B Cell Lymphomagenesis.

The gene encoding the MEF2B transcription factor is mutated in germinal center (GC)-derived B cell lymphomas, but its role in GC development and lymphomagenesis is unknown. We demonstrate that Mef2b deletion reduces GC formation in mice and identify MEF2B transcriptional targets in GC, with roles in cell proliferation, apoptosis, GC confinement, and differentiation. The most common lymphoma-associated MEF2B mutant (MEF2BD83V) is hypomorphic, yet escapes binding and negative regulation by components of the HUCA complex and class IIa HDACs. Mef2bD83V expression in mice leads to GC enlargement and lymphoma development, a phenotype that becomes fully penetrant in combination with BCL2 de-regulation, an event associated with human MEF2B mutations. These results identify MEF2B as a critical GC regulator and a driver oncogene in lymphomagenesis.

Mutations targeting the coagulation pathway are enriched in brain metastases.

Brain metastases (BMs) are the most common malignancy of the central nervous system. Recently it has been demonstrated that plasminogen activator inhibitor serpins promote brain metastatic colonization, suggesting that mutations in serpins or other members of the coagulation cascade can provide critical advantages during BM formation. We performed whole-exome sequencing on matched samples of breast cancer and BMs and found mutations in the coagulation pathway genes in 5 out of 10 BM samples. We then investigated the mutational status of 33 genes belonging to the coagulation cascade in a panel of 29 BMs and we identified 56 Single Nucleotide Variants (SNVs). The frequency of gene mutations of the pathway was significantly higher in BMs than in primary tumours, and SERPINI1 was the most frequently mutated gene in BMs. These findings provide direction in the development of new strategies for the treatment of BMs.

Functional role of CLIC1 ion channel in glioblastoma-derived stem/progenitor cells.

BACKGROUND: Chloride channels are physiologically involved in cell division and motility. Chloride intracellular channel 1 (CLIC1) is overexpressed in a variety of human solid tumors compared with normal tissues, suggesting a potential involvement of CLIC1 in the regulation of tumorigenesis. This led us to investigate the role of CLIC1 in gliomagenesis. METHODS: We used the neurosphere system to isolate stem/progenitor cells from human glioblastomas (GBMs). CLIC1 targeting in GBM neurospheres was achieved by both lentiviral-mediated short-hairpin RNA transduction and CLIC1 antibody treatment, and its effect on stem-like properties was analyzed in vitro by proliferation and clonogenic assays and in vivo by orthotopic injection in immunocompromised mice. Channel activity was studied by perforated patch clamp technique. Differences in expression were analyzed by analysis of variance with Tamhane's multiple comparison test. Kaplan-Meier analyses and log-rank test were used to assess survival. All statistical tests were two-sided. RESULTS: CLIC1 was statistically significantly overexpressed in GBMs compared with normal brain tissues (P < .001) with a better survival of patients with CLIC1 low-expressing tumors (CLIC1(low) vs CLIC1(high) survival: χ(2) = 74.35; degrees of freedom = 1; log-rank P < .001). CLIC1 was variably expressed in patient-derived GBM neurospheres and was found enriched in the stem/progenitor compartment. CLIC1 silencing reduced proliferative (P < .01), clonogenic (P < .01), and tumorigenic capacity (P < .05) of stem/progenitor cells. The reduction of CLIC1 chloride currents with a specific CLIC1 antibody mirrored the biological effects of CLIC1 silencing in GBM patient-derived neurospheres. CONCLUSIONS: Reduced gliomagenesis after CLIC1 targeting in tumoral stem/progenitor cells and the finding that CLIC1 expression is inversely associated with patient survival suggest CLIC1 as a potential target and prognostic biomarker.

Marker-independent method for isolating slow-dividing cancer stem cells in human glioblastoma.

Glioblastoma (GBM) is a devastating brain tumor with a poor survival outcome. It is generated and propagated by a small subpopulation of rare and hierarchically organized cells that share stem-like features with normal stem cells but, however, appear dysregulated in terms of self-renewal and proliferation and aberrantly differentiate into cells forming the bulk of the disorganized cancer tissues. The complexity and heterogeneity of human GBMs underlie the lack of standardized and effective treatments. This study is based on the assumption that available markers defining cancer stem cells (CSCs) in all GBMs are not conclusive and further work is required to identify the CSC. We implemented a method to isolate CSCs independently from cell surface markers: four patient-derived GBM neurospheres containing stem, progenitors, and differentiated cells were labeled with PKH-26 fluorescent dye that reliably selects for cells that divide at low rate. Through in vitro and in vivo assays, we investigated the growth and self-renewal properties of the two different compartments of high- and slow-dividing cells. Our data demonstrate that only slow-dividing cells retain the ability of a long-lasting self-renewal capacity after serial in vitro passaging, while high-dividing cells eventually exhaust. Moreover, orthotopic transplantation assay revealed that the incidence of tumors generated by the slow-dividing compartment is significantly higher in the four patient-derived GBM neurospheres analyzed. Importantly, slow-dividing cells feature a population made up of homogeneous stem cells that sustain tumor growth and therefore represent a viable target for GBM therapy development.

Outcome and clinico-biological characteristics of advanced breast cancer patients with surgically resected brain metastases: a multidisciplinary approach.

BACKGROUND: Despite improvements in brain surgery and radiotherapy, patients with brain metastases (BM) from breast cancer still have a poor prognosis. The aim of the present study is to evaluate the outcome of a multimodal therapeutic strategy in an unselected cohort of patients. METHODS: We retrospectively reviewed 24 breast cancer patients who developed BM and were treated with brain surgery, radiotherapy, and/or systemic therapy in the same institutions. RESULTS: Primary treatment for BM was surgery in the whole cohort, radiotherapy in 11 patients, radiotherapy combined with systemic therapy in nine patients, and systemic therapy as single treatment in six patients (chemo/targeted therapy n= 4; hormonal therapy n=2). The median time from breast cancer diagnosis to brain surgery was 57.6 months (range 1.8-130.7 months). The overall survival from surgery for BM was 22 months and the overall survival from BM surgery by presence of other metastatic sites at surgery was 25 months for patients with BM only and 11 months for patients with other metastatic sites (p=0.046). CONCLUSION: Although this study is retrospective and limited by the small number of patients, the overall survival of 22 months from the time of brain surgery represents an excellent outcome. The multidisciplinary approach that combines the efforts of specialists from different disciplines leads to satisfactory results for patients in terms of survival in the current clinical practice and prospective subtype-oriented trials are urgently required in this category of patients.

CD133 is essential for glioblastoma stem cell maintenance.

The role of the cell surface CD133 as a cancer stem cell marker in glioblastoma (GBM) has been widely investigated, since it identifies cells that are able to initiate neurosphere growth and form heterogeneous tumors when transplanted in immune-compromised mice. However, evidences of CD133-negative cells exhibiting similar properties have also been reported. Moreover, the functional role of CD133 in cancer stem/progenitor cells remains poorly understood. We studied the biological effects of CD133 downregulation in GBM patient-derived neurospheres. Our results indicate that there is not a hierarchical relation between CD133-positive and CD133-negative cells composing the neurospheres. Indeed, CD133 appears in an interconvertible state, changing its subcellular localization between the cytoplasm and the plasmamembrane of neurosphere cells. Silencing of CD133 in human GBM neurospheres using lentivirus-mediated short hairpin RNA impairs the self-renewal and tumorigenic capacity of neurosphere cells. These results imply that CD133 could be used as a therapeutic target in GBMs.

Acute and chronic effects of therapeutic apheresis.

In most patients only a few sessions of apheresis treatment are necessary to see the benefit. This is the case of immunological diseases when the production of a pathologic component is limited in time or in microcirculation disturbances when changes of vascular function may occur. In the first instance the acute effect is likely due to the removal of the corresponding antibody, while in the second case the improvement of the endothelium-dependent vasodilation and the reduction of blood viscosity play a major role. In long-term treatment, as in the case of patients affected by familial hypercholesterolemia, the chronic effects of apheresis may lead to the repair of morphological alterations in the vascular wall. We report the recovery from ulcers in two hemodialysis patients suffering from peripheral arterial disease as the result of twenty-two sessions of rheopheresis. The reasons that justify these chronic actions may involve pleiotropic effects that are different according to the apheresis technique used.

[Chronic kidney disease in the province of Mantua and its developments over the last 40 years]. / Evoluzione della malattia renale cronica nella provincia di Mantova in 40 anni.

The incidence and prevalence of end-stage renal disease increased steadily for 35 years in the population of Italy's Mantua province until the end of 2007, when they started to decrease. We describe the results of providing information and raising awareness among residents of the province's capital, Mantua, and of direct teaching and short training courses in hospital wards for general practitioners over a period of 3 years. During this period there was also more consultation activity for all kidney outpatients, from the first to the last stages of chronic kidney disease. Clinical data collected by the local NHS section (ASL) showed an increase in age and comorbidities (mainly type 2 diabetes) in kidney patients. As a result of the preventive measures, there has been an effective reduction of the yearly incidence and prevalence for all kinds of treatment, with the exception of kidney transplants, which have increased progressively during the last years.

[Production and control of water quality for hemodialysis]. / Produzione e controllo della qualita' dell'acqua per emodialisi.

Certain substances present in drinking water can harm hemodialysis patients if they are not removed before the preparation of the dialysate. An optimal water treatment system includes tap water pretreatment and a double reverse osmosis process. Every component, including the delivery of the treated water to the dialysis machines, contributes to preventing chemical and microbiological contamination. Quality standards for dialysis water do not differ from those for intravenous drug safety and the progress toward the goals depends on practical solutions to important issues, including how the standard is to be applied and whether it should be limited to substances with well-documented toxicity in hemodialysis patients, and how microbiological contaminants should be handled. Meeting the standards for the new dialysis methods and membranes requires protocols for the development of a facility-specific quality management system to ensure dialysate quality based on the validation of system performance coupled with routine monitoring and periodic revalidation.

Current strategies for identification of glioma stem cells: adequate or unsatisfactory?

Cancer stem cells (CSCs) were isolated in multiple tumor types, including human glioblastomas, and although the presence of surface markers selectively expressed on CSCs can be used to isolate them, no marker/pattern of markers are sufficiently robust to definitively identify stem cells in tumors. Several markers were evaluated for their prognostic value with promising early results, however none of them was proven to be clinically useful in large-scale studies, leading to outstanding efforts to identify new markers. Given the heterogeneity of human glioblastomas further investigations are necessary to identify both cancer stem cell-specific markers and the molecular mechanisms sustaining the tumorigenic potential of these cells to develop tailored treatments. Markers for glioblastoma stem cells such as CD133, CD15, integrin-α6, L1CAM might be informative to identify these cells but cannot be conclusively linked to a stem cell phenotype. Overlap of expression, functional state and morphology of different subpopulations lead to carefully consider the techniques employed so far to isolate these cells. Due to a dearth of methods and markers reliably identifying the candidate cancer stem cells, the isolation/enrichment of cancer stem cells to be therapeutically targeted remains a major challenge.

Therapeutic apheresis in peripheral and retinal circulatory disorders.

In microcirculation disorders, the therapeutic apheresis seems to have two different effects. The first, achieved after only a few sessions, is acute, consisting of drastic reduction of blood viscosity and obtained with the use of low-density lipoprotein (LDL) apheresis, rheopheresis, or fibrinogen apheresis. The second effect is long term, or chronic, and needs to be evaluated after a long course of treatment. The mechanisms underlying the chronic effect are still objects of debate and take into account the pleiotropic effects of apheresis. However, it is likely that the acute effect of apheresis mainly influences the functional components of the vascular damage, and so the derived rheological benefit might last only for a short period. The chronic effect, on the contrary, by acting on the morphological alterations of the vascular walls, requires the apheresis treatment to be prolonged for a longer period or even cycles of treatment to be programmed.

[Effects of cascade filtration in combination with interferon and ribavirin in the treatment non responder chronic hepatitis C patients]. / La filtrazione a cascata nei pazienti HCV positivi.

In 40% of patients with chronic hepatitis C, standard therapy is unable to eradicate the virus. Since the response to pharmacological treatment depends on the initial viral load, there is a rationale for reducing this load by means of apheretic depletion of the C virus. The aim of this work was to administer cascade filtration (CF) to non responder patients affected by hepatitis C (pts) before resuming the pharmacological treatment. 10 pts underwent 12 sessions of CF, 3 per week (treated plasma volume/session: 3000 mL). After the first week, therapy with PEG-IFN (1.5 ug/Kg/week) plus Ribavirin (1200 mg/day) was added. The viral load was determined before and after each CF session, and at the 1st, 3rd and 6th month. The mean pre-apheresis viral load dropped from 2176275+/-3109997 U/mL at the first session to 1486726+/-2091975 U/mL by the fourth (p<0.001), and 347500+/-637428 U/mL before the last (p<0.001). The mean percentage reduction of the viral load went from a minimum of 29.5% to a maximum of 42%. Early viral response (EVR) was obtained in 70% of these patients as compared with only 10% in an age- and sex-matched control group consisting of 10 patients. Unfortunately, we did not get the same good results in terms of sustained viral response (SVR: 10% in apheretic patients vs 0% in the control group). Efficacious removal of HCV was obtained with CF. However, the successful reduction in the viral load achieved with apheresis in terms of EVR was not confirmed when we considered the SVR.

Rai is a new regulator of neural progenitor migration and glioblastoma invasion.

The invasive nature of glioblastoma (GBM) is one important reason for treatment failure. GBM stem/progenitor cells retain the migratory ability of normal neural stem/progenitor cells and infiltrate the brain parenchyma. Here, we identify Rai (ShcC/N-Shc), a member of the family of Shc-like adaptor proteins, as a new regulator of migration of normal and cancer stem/progenitor cells. Rai is expressed in neurogenic areas of the brain and its knockdown impairs progenitor migration to the olfactory bulb. Its expression is retained in GBM stem/progenitor cells where it exerts the same promigratory activity. Rai silencing in cancer stem/progenitor cells isolated from different patients causes significant decrease in cell migration and invasion, both in vitro and in vivo, providing survival benefit. Rai depletion is associated with alteration of multiple-signaling pathways, yet it always leads to reduced expression of proinvasive genes.

Endothelial progenitor cells in sudden sensorineural hearing loss.

CONCLUSIONS: Endothelial progenitor cells (EPCs) are a unique subtype of circulating cells with properties similar to those of embryonal angioblasts. They have the potential to proliferate and to differentiate into mature endothelial cells. EPCs are reduced in patients with vascular risk factors due to a decreased mobilization, an increased consumption at the site of damage or a reduced half-life. The results of this study confirm the existence of an endothelial dysfunction in patients with sudden sensorineural hearing loss (SSHL) and support the vascular involvement in the pathogenesis of the disease. OBJECTIVE: The aim of this study was to evaluate the concentration of EPCs in patients affected by SSHL. METHODS: Twenty-one patients affected by SSHL were evaluated. The number of EPCs was analyzed by flow cytometry analysis of peripheral blood CD34+KDR+CD133+ cells. RESULTS: Circulating levels of EPCs were significantly lower in SSHL patients compared with controls. In particular, CD34+KDR+ cells and CD34+CD133+KDR+ cells were significantly reduced (p < 0.05).