The oleic/palmitic acid imbalance in exosomes isolated from NAFLD patients induces necroptosis of liver cells via the elongase-6/RIP-1 pathway.

Excessive toxic lipid accumulation in hepatocytes underlies the development of non-alcoholic fatty liver disease (NAFLD), phenotypically characterized by necrosis and steato-fibrosis, whose molecular mechanism is not yet fully understood. Patients with NAFLD display an imbalanced palmitic (PA) to oleic acid (OA) ratio. Moreover, increasing experimental evidence points out a relevant involvement of the exosomal content in disease progression. Aim of the study was to highlight the PA/OA imbalance within circulating exosomes, the subsequent intracellular alterations, and the impact on NALFD. Liver cells were challenged with exosomes isolated from both healthy subjects and NAFLD patients. The exosomal PA/OA ratio was artificially modified, and biological effects were evaluated. A NAFLD-derived exosomal PA/OA imbalance impacts liver cell cycle and cell viability. OA-modified NAFLD-derived exosomes restored cellular viability and proliferation, whereas the inclusion of PA into healthy subjects-derived exosomes negatively affected cell viability. Moreover, while OA reduced the phosphorylation and activation of the necroptosis marker, Receptor-interacting protein 1 (phospho-RIP-1), PA induced the opposite outcome, alongside increased levels of stress fibers, such as vimentin and fibronectin. Administration of NAFLD-derived exosomes led to increased expression of Elongase 6 (ELOVL6), Stearoyl-CoA desaturase 1 (SCD1), Tumor necrosis factor α (TNF-α), Mixed-lineage-kinase-domain-like-protein (MLKL) and RIP-1 in the hepatocytes, comparable to mRNA levels in the hepatocytes of NAFLD patients reported in the Gene Expression Omnibus (GEO) database. Genetic and pharmacological abrogation of ELOVL6 elicited a reduced expression of downstream molecules TNF-α, phospho-RIP-1, and phospho-MLKL upon administration of NAFLD-derived exosomes. Lastly, mice fed with high-fat diet exhibited higher phospho-RIP-1 than mice fed with control diet. Targeting the Elongase 6-RIP-1 signaling pathway offers a novel therapeutic approach for the treatment of the NALFD-induced exosomal PA/OA imbalance.

Bioaccessibility and Bioavailability of Diet Polyphenols and Their Modulation of Gut Microbiota.

It is generally accepted that diet-derived polyphenols are bioactive compounds with several potentially beneficial effects on human health. In general, polyphenols have several chemical structures, and the most representative are flavonoids, phenolic acids, and stilbenes. It should be noted that the beneficial effects of polyphenols are closely related to their bioavailability and bioaccessibility, as many of them are rapidly metabolized after administration. Polyphenols-with a protective effect on the gastrointestinal tract-promote the maintenance of the eubiosis of the intestinal microbiota with protective effects against gastric and colon cancers. Thus, the benefits obtained from dietary supplementation of polyphenols would seem to be mediated by the gut microbiota. Taken at certain concentrations, polyphenols have been shown to positively modulate the bacterial component, increasing Lactiplantibacillus spp. and Bifidobacterium spp. involved in the protection of the intestinal barrier and decreasing Clostridium and Fusobacterium, which are negatively associated with human well-being. Based on the diet-microbiota-health axis, this review aims to describe the latest knowledge on the action of dietary polyphenols on human health through the activity of the gut microbiota and discusses micro-encapsulation of polyphenols as a strategy to improve the microbiota.

Plasma-Derived Exosomes from NAFLD Patients Modulate the Cannabinoid Receptors' Expression in Cultured HepaRG Cells.

Exosomes produced by hepatocytes upon lipotoxic insult play a relevant role in pathogenesis of nonalcoholic fatty liver disease (NAFLD), suggesting an inflammatory response by the activation of monocytes and macrophages and accelerating the disease progression. In the pathogenesis of NAFLD and liver fibrosis, the endogenous cannabinoids and their major receptors CB1 and CB2 appear to be highly involved. This study aimed at evaluating the expression of cannabinoids receptors (CB1R and CB2R) in plasma-derived exosomes extracted from patients with NAFLD, as well as investigating the in vitro effects of the circulating exosomes in cultured human HepaRG cells following their introduction into the culture medium. The results demonstrated that plasma-derived exosomes from NAFLD patients are vehicles for the transport of CB1R and are able to modulate CB receptors' expression in HepaRG cells. In particular, circulating exosomes from NAFLD patients are inflammatory drivers for HepaRG cells, acting through CB1R activation and the downregulation of CB2R. Moreover, CB1R upregulation was associated with increased expression levels of PPAR-γ, a well-known mediator of liver tissue injury. In conclusion, this study provides evidence for CB1R transport by exosomes and suggests that the in vitro effects of circulating exosomes from NAFLD patients are mediated by the expression of cannabinoid receptors.

Anti-Proliferative and Pro-Apoptotic Effects of Digested Aglianico Grape Pomace Extract in Human Colorectal Cancer Cells.

Grape pomace (GP)-the major by-product of winemaking processes-still contains bioactive molecules with known beneficial properties for human health, such as an antiradical scavenging activity or an antiproliferative activity of tumors. In vitro studies have demonstrated that GP polyphenols specifically influence colon cancer cell proliferation. In addition to previously published work, we tested the phenolic compounds of Aglianico GP following an in vitro simulated gastrointestinal digestion on colorectal cancer cell lines at different degrees of differentiation. Our experiments, using HT29 and SW480 cells, confirmed the anti-proliferative effect of GP gastrointestinal digested extract and provided intriguing insights on the way it influences the cancer cell features (i.e., viability, proliferation, and apoptosis). We observed that Aglianico GP extract showed a great ability to affect cell proliferation and apoptosis. Interestingly, both HT29 and SW480 cells produced a significant increase in Bax, and a significant increase in the Bax/Bcl-2 ratio and caspase-3. The gastrointestinal digested GP extract was previously characterized both for antioxidant activity and phenolic composition. As a result, the TPC and the antioxidant activity reached high values in the Aglianico GP digested extract, and the main compounds assessed by UHPLC-DAD were anthocyanins, phenolic acids, and flavonoids. This work shed light on the use of digested GP extract as a dietary ingredient, a very sustainable source of nutritional compounds with potential health benefits for colon cancer cell proliferation.

Beneficial Effects of Table Grape Use on Serum Levels of Omega-3 Index and Liver Function: A Randomized Controlled Clinical Trial.

This clinical trial was aimed to investigate the effects of fresh table grape intake on the serum levels of the Omega-3 index, defined as the sum of eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) levels. Forty consecutive healthy subjects were randomly assigned to the control group, receiving only dietary recommendations, and the grape group receiving a daily dose of 5 g of fresh table grape per kg of body weight, for 21 days. Compared with baseline, the grape treatment produced no significant difference in the serum levels of glucose, liver transaminase, and triglycerides, with the exception of cholesterol value, which was significantly reduced in both control and grape group (180.5 ± 20.32 vs. 196.1 ± 30.0 and 181.4 ± 21.9 vs. 194.3 ± 37.5, respectively). After 4 weeks from the end of grape treatment, the analysis of single fatty acids showed a significant increase in oleic acid content (14.15 ± 1.8 vs. 12.85 ± 1.6, p < 0.05) and a significant induction of the Omega-3 index (8.23 ± 1.9 vs. 6.09 ± 1.2, p < 0.05), associated with increased serum levels of adiponectin (24.09 ± 1.08 vs. 8.8 ± 0.7, p < 0.001). In contrast, the expression of fibroblast growth factor 21 (FGF21), a molecule associated with metabolic syndrome and liver disease, was significantly reduced (37.9 ± 6.8 vs. 107.8 ± 10.1, p < 0.001). The data suggest that the intake of fresh grape improves the Omega-3 index in the serum and exerts beneficial effects on liver function through the overexpression of adiponectin and the reduction in FGF21 levels.

How Metabolomics Provides Novel Insights on Celiac Disease and Gluten-Free Diet: A Narrative Review.

Celiac disease (CD) is an inflammatory autoimmune disorder triggered by the ingestion of gluten from wheat and other cereals. Nowadays, its positive diagnosis is based on invasive approaches such as the histological examination of intestinal biopsies and positive serology screening of antibodies. After proven diagnosis, the only admissible treatment for CD individuals is strict life-long adherence to gluten-free diet (GFD), although it is not a conclusive therapy. Acting by different mechanisms and with different etiologies, both CD and GFD have a great impact on gut microbiota that result in a different taxa composition. Altered production of specific metabolites reflects these microbiota changes. In this light, the currently available literature reports some suggestions about the possible use of specific metabolites, detected by meta-omics analyses, as potential biomarkers for a CD non-invasive diagnosis. To highlight insights about metabolomics application in CD study, we conducted a narrative dissertation of selected original articles published in the last decade. By applying a systematic search, it clearly emerged how the metabolomic signature appears to be contradictory, as well as poorly investigated.

Nutraceuticals: Focus on Anti-Inflammatory, Anti-Cancer, Antioxidant Properties in Gastrointestinal Tract.

In recent years, nutraceuticals have gained great popularity, owing to their physiological and potential health effects, such as anti-inflammatory, anti-cancer, antioxidant, and prebiotic effects, and their regulation of lipid metabolism. Since the Mediterranean diet is a nutritionally recommended dietary pattern including high-level consumption of nutraceuticals, this review aimed to summarize the main results obtained by our in vitro and in vivo studies on the effects of the major constituents of the Mediterranean diet (i.e., extra virgin olive oil compounds, polyunsaturated fatty acids, and fruit components). Based on experimental studies, the therapeutic purpose of nutraceuticals depends on their bioavailability, solubility, toxicity, and delivery system. This review provides more in-depth knowledge on the effects linked to nutraceuticals administration on human health, focusing the gastrointestinal tract and suggesting specific dietary components for personalized adjuvant therapies.

A Low Glycemic Index Mediterranean Diet Combined with Aerobic Physical Activity Rearranges the Gut Microbiota Signature in NAFLD Patients.

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease, and its prevalence worldwide is increasing. Several studies support the pathophysiological role of the gut-liver axis, where specific signal pathways are finely tuned by intestinal microbiota both in the onset and progression of NAFLD. In the present study, we investigate the impact of different lifestyle interventions on the gut microbiota composition in 109 NAFLD patients randomly allocated to six lifestyle intervention groups: Low Glycemic Index Mediterranean Diet (LGIMD), aerobic activity program (ATFIS_1), combined activity program (ATFIS_2), LGIMD plus ATFIS_1 or ATFIS2 and Control Diet based on CREA-AN (INRAN). The relative abundances of microbial taxa at all taxonomic levels were explored in all the intervention groups and used to cluster samples based on a statistical approach, relying both on the discriminant analysis of principal components (DAPCs) and on a linear regression model. Our analyses reveal important differences when physical activity and the Mediterranean diet are merged as treatment and allow us to identify the most statistically significant taxa linked with liver protection. These findings agree with the decreased 'controlled attenuation parameter' (CAP) detected in the LGIMD-ATFIS_1 group, measured using FibroScan®. In conclusion, our study demonstrates the synergistic effect of lifestyle interventions (diet and/or physical activity programs) on the gut microbiota composition in NAFLD patients.

Exposure assessment to inhalable and respirable dust in the post - earthquake construction sites in the city of l'Aquila.

OBJECTIVES: Following an earthquake that occurred in middle Italy in 2009, the involved territory hosted in 10 years thousands of construction sites. The aim of this study is to assess inhalable, respirable, and respirable crystalline silica exposure of the construction workers involved in the rebuilding activities. METHODS: Six construction companies joined the study and hosted the air sampling activities. We identified four work tasks: bricklayer and similar; scaffolder and carpenter; manual demolition; other tasks. We reported 8-h time-weighted concentrations. RESULTS: The "All tasks" geometric mean concentration of inhalable dust was 4.73 mg/m3 and the higher, TLV exceeding exposure was observed for "Manual demolition workers" (13.92 mg/m3 , GM). The "All tasks" geometric mean concentration of respirable dust was 0.25 mg/m3 and no TLV-exceeding exposure (geometric mean values) was observed among the work-related groups. About the respirable crystalline silica dust exposure, the "All tasks" average concentration was 0.004 mg/m3 . No TLV-exceeding exposure was observed among the whole data sample. CONCLUSIONS: The comparison of the results shows that manual demolition workers are exposed to high levels of inhalable dust, exceeding the TLV-TWA (Threshold Limit Values-Time Weighted Average) limit of 10 mg/m3 . About the respirable dust concentration, none of the analyzed work task dust concentrations exceeded the TLV-TWA limit of 3 mg/m3 (geometric mean values). Measurements of respirable crystalline silica dust have shown levels below the threshold limit value of 0.025 mg/m3 . Our findings overall match with the available scientific data.

Impact of Fresh Table Grape Intake on Circulating microRNAs Levels in Healthy Subjects: A Significant Modulation of Gastrointestinal Cancer-Related Pathways.

SCOPE: The study aims to investigate the effects of fresh table grape consumption in healthy subjects on circulating levels of the most common human microRNAs (miRNAs). The regulatory network governed by these modulated miRNAs is also investigated. METHODS AND RESULTS: Autumn Royal table grape, used in this study, is chosen for its high polyphenolic content and antioxidant properties. The study is a randomized controlled trial, in which 40 consecutive subjects are recruited on a voluntary basis and randomly assigned to two groups of the study, the control group, receiving only dietary recommendations and a grape group receiving a daily dose of 5 g of fresh table grape per kg of body weight for 21 days. All analyses are performed at baseline and after 21 days of dietary treatment. Circulating miRNAs levels are detected by Real-Time quantitative PCR (RT-qPCR) followed by bioinformatic functional analysis. The study identifies 20 circulating miRNAs differentially expressed in healthy subjects after grape intake, and in particular, 18 of 20 are down-regulated and 2 are up-regulated. CONCLUSION: The dietary intake of table grape affects circulating miRNAs levels in healthy subjects, particularly the miRNAs related to pathways involved in counteracting cancer development, including gastrointestinal cancers.

Nonalcoholic Fatty Liver Disease: Focus on New Biomarkers and Lifestyle Interventions.

Nonalcoholic fatty liver disease (NAFLD) is considered a hepatic manifestation of metabolic syndrome, characterized from pathological changes in lipid and carbohydrate metabolism. Its main characteristics are excessive lipid accumulation and oxidative stress, which create a lipotoxic environment in hepatocytes leading to liver injury. Recently, many studies have focused on the identification of the genetic and epigenetic modifications that also contribute to NAFLD pathogenesis and their prognostic implications. The present review is aimed to discuss on cellular and metabolic alterations associated with NAFLD, which can be helpful to identify new noninvasive biomarkers. The identification of accumulated lipids in the cell membranes, as well as circulating cytokeratins and exosomes, provides new insights in understanding of NAFLD. This review also suggests that lifestyle modifications remain the main prevention and/or treatment for NAFLD.