Insulin resistance and Metabolic dysfunction-associated steatotic liver disease (MASLD): Pathways of action of hypoglycemic agents.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is characterized by overweight/obesity, and the presence of type 2 diabetes mellitus is the most important criterion. We propose an independent disease perspective without exclusion criteria and with less heterogeneity and greater impact because, according to the National Health and Nutrition Survey (ENSANUT), in Mexico, 25 % of adults over 60 years of age suffer from diabetes, and 96 % of those over 50 years of age have abdominal obesity. Due to the impact of insulin resistance in the pathophysiology of MASLD, which results in damage to hepatocytes, this work aims to provide an overview of the action pathways of hypoglycemic agents such as glucagon-like-1 receptor agonist and peroxisome proliferator-activated receptor-gamma agonists, whose importance lies in the fact that they are currently undergoing phase 2 studies, as well as dipeptidyl peptidase 4 inhibitors and sodium-glucose co-transporter type 2 inhibitors, which are undergoing phase 1 study trials.

Clostridioides Difficile in Latin America: An Epidemiological Overview.

Clostridioides difficile infection is one of the most significant causes of nosocomial diarrhea associated with antibiotic use worldwide. In recent years, the incidence of Clostridioides difficile infection in Latin American countries has increased due to the emergence and spread of epidemic Clostridioides difficile strains, such as RT027/NAP1/ST1, RT078/ST11, and RT017/ST37; additionally, endemic multi-drug-resistant strains have recently appeared due to the lack of heterogeneous diagnostic algorithms and guidelines for antibiotic use in each country. The aim of this review is to present the latest information regarding Clostridioides difficile and emphasize the importance of epidemiological surveillance of this pathogen in Latin American countries.

Inulin Improves Diet-Induced Hepatic Steatosis and Increases Intestinal Akkermansia Genus Level.

Hepatic steatosis is characterized by triglyceride accumulation within hepatocytes in response to a high calorie intake, and it may be related to intestinal microbiota disturbances. The prebiotic inulin is a naturally occurring polysaccharide with a high dietary fiber content. Here, we evaluate the effect of inulin on the intestinal microbiota in a non-alcoholic fatty liver disease model. Mice exposed to a standard rodent diet or a fat-enriched diet, were supplemented or not, with inulin. Liver histology was evaluated with oil red O and H&E staining and the intestinal microbiota was determined in mice fecal samples by 16S rRNA sequencing. Inulin treatment effectively prevents liver steatosis in the fat-enriched diet group. We also observed that inulin re-shaped the intestinal microbiota at the phylum level, were Verrucomicrobia genus significantly increased in the fat-diet group; specifically, we observed that Akkermansia muciniphila increased by 5-fold with inulin supplementation. The family Prevotellaceae was also significantly increased in the fat-diet group. Overall, we propose that inulin supplementation in liver steatosis-affected animals, promotes a remodeling in the intestinal microbiota composition, which might regulate lipid metabolism, thus contributing to tackling liver steatosis.

Can topical epinephrine application to the papilla prevent pancreatitis after endoscopic retrograde cholangiopancreatography? Results from a double blind, multicentre, placebo controlled, randomised clinical trial.

BACKGROUND AND STUDY AIMS: Post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP) is a complication associated with important morbidity, occasional mortality and high costs. Preventive strategies are suboptimal as PEP continues to affect 4% to 9% of patients. Spraying epinephrine on the papilla may decrease oedema and prevent PEP. This study aimed to compare rectal indomethacin plus epinephrine (EI) versus rectal indomethacin plus sterile water (WI) for the prevention of PEP. PATIENTS AND METHODS: This multicentre randomised controlled trial included patients aged >18 years with an indication for ERCP and naive major papilla. All patients received 100 mg of rectal indomethacin and 10 mL of sterile water or a 1:10 000 epinephrine dilution. Patients were asked about PEP symptoms via telephone 24 hours and 7 days after the procedure. The trial was stopped half way through after a new publication reported an increased incidence of PEP among patients receiving epinephrine. RESULTS: Of the 3602 patients deemed eligible, 3054 were excluded after screening. The remaining 548 patients were randomised to EI group (n=275) or WI group (n=273). The EI and WI groups had similar baseline characteristics. Patients in the EI group had a similar incidence of PEP to those in the WI group (3.6% (10/275) vs 5.12% (14/273), p=0.41). Pancreatic duct guidewire insertion was identified as a risk factor for PEP (OR 4.38, 95% CI (1.44 to 13.29), p=0.009). CONCLUSION: Spraying epinephrine on the papilla was no more effective than rectal indomethacin alone for the prevention of PEP. TRIAL REGISTRATION NUMBER: This study was registered with ClinicalTrials.gov (NCT02959112).

G protein-coupled receptors: Key molecules in metabolic associated fatty liver disease development.

Metabolic associated fatty liver disease (MAFLD) is a range of hepatic disorders with progression to steatohepatitis with risk of development of fibrosis, cirrhosis, and hepatocellular carcinoma. MAFLD is strongly related to metabolic disorders of active fatty acids, which seem to be selective according to their specific ligand of G protein-coupled receptors (GPRs) located in immune response cells. An approach to study the pathophysiological mechanisms of MAFLD could be through the expression of active fatty acids ligands. The expression of GPRs is associated with obesity, microbiota environment, and dietary characteristics in patients with MAFLD. More specifically, GPR41, GPR43, GPR20, and GPR120 have been associated with alteration of lipid metabolism in hepatic and intestinal cells, and consequently they have a key role in metabolic diseases. We observed that GPR120 is not expressed in nonoverweight/obese patients, regardless of the presence of MAFLD; meanwhile the expression of GPR41 is increased in patients with lean MAFLD. GPRs role in liver disease is intriguing and a field of research opportunity. More studies are necessary to define the role of active fatty acids in the development of metabolic diseases.

Molecular Epidemiology and Antimicrobial Resistance of Clostridioides difficile in Hospitalized Patients From Mexico.

Clostridioides difficile is a global public health problem, which is a primary cause of antibiotic-associated diarrhea in humans. The emergence of hypervirulent and antibiotic-resistant strains is associated with the increased incidence and severity of the disease. There are limited studies on genomic characterization of C. difficile in Latin America. We aimed to learn about the molecular epidemiology and antimicrobial resistance in C. difficile strains from adults and children in hospitals of México. We studied 94 C. difficile isolates from seven hospitals in Mexico City from 2014 to 2018. Whole-genome sequencing (WGS) was used to determine the genotype and examine the toxigenic profiles. Susceptibility to antibiotics was determined by E-test. Multilocus sequence typing (MLST) was used to determine allelic profiles. Results identified 20 different sequence types (ST) in the 94 isolates, mostly clade 2 and clade 1. ST1 was predominant in isolates from adult and children. Toxigenic strains comprised 87.2% of the isolates that were combinations of tcdAB and cdtAB (tcdA+/tcdB+/cdtA+/cdtB+, followed by tcdA+/tcdB+/cdtA-/cdtB-, tcdA-/tcdB+/cdtA-/ cdtB-, and tcdA-/tcdB-/cdtA+/cdtB+). Toxin profiles were more diverse in isolates from children. All 94 isolates were susceptible to metronidazole and vancomycin, whereas a considerable number of isolates were resistant to clindamycin, fluroquinolones, rifampicin, meropenem, and linezolid. Multidrug-resistant isolates (≥3 antibiotics) comprised 65% of the isolates. The correlation between resistant genotypes and phenotypes was evaluated by the kappa test. Mutations in rpoB and rpoC showed moderate concordance with resistance to rifampicin and mutations in fusA substantial concordance with fusidic acid resistance. cfrE, a gene recently described in one Mexican isolate, was present in 65% of strains linezolid resistant, all ST1 organisms. WGS is a powerful tool to genotype and characterize virulence and antibiotic susceptibility patterns.

Dietary consumption and serum pattern of bioactive fatty acids in NAFLD patients.

INTRODUCTION AND OBJECTIVES: Nonalcoholic fatty liver disease (NAFLD) is the hepatic manifestation of metabolic syndrome. Some dietary fatty acids have showed different bioactive functions in metabolic syndrome. The aim of this study is to determine the dietary consumption patterns and serum percentage of bioactive fatty acids in NAFLD patients. PATIENTS AND METHODS: Cross-sectional study with NAFLD patients and non-NAFLD patients. Dietary consumption of bioactive fatty acids was assessed by a food frequency questionnaire. NAFLD and liver fibrosis were diagnosed by transient elastography. The identification of serum bioactive fatty acids was achieved by gas chromatography-mass spectrometry (%). Bioactive fatty acids consumption was correlated with NAFLD clinical characteristics with the Spearman correlation analysis. RESULTS: A total of 299 patients were included, whose mean of age and body mass index were 44.2±9.9 years and 25.9±3.8kg/m2, respectively. The consumption of bioactive fatty acids was no different regarding the presence of NAFLD; however, the consumption of stearic and linoleic fatty acids was higher in relation with NAFLD severity (p≤0.05). The consumption of myristic acid was higher in patients with fibrosis (p=0.02). Serum percentage and dietary consumption did not show correlations. CONCLUSION: Dietary consumption of bioactive fatty acids is different according to NAFLD severity. Individualized diets according to NAFLD severity could be successful in order to prevent liver injury-related outcomes.

Sarcopenia in chronic liver diseases: a translational overview.

INTRODUCTION: Sarcopenia refers to a progressive and generalized muscle mass and strength loss. In liver diseases, it has been related to worse outcomes and high risk of decompensations. AREAS COVERED: Sarcopenia is caused by a set of cellular processes in the muscle such as denervation, mitochondrial dysfunction, endotoxemia and inflammation; which are manifested through the alteration of several proteolytic pathways such as lysosomal, proteasomal and caspase systems. In autophagy, myostatin and oxidative stress; such as hyperammonemia, contributes importantly to liver sarcopenia through loss of muscle mass already demonstrated in in vitro and in vivo models. In addition, hormones and the regulation of the intestinal microbiota, influence in a not less important magnitude. In the clinical setting, early identification of sarcopenia has been established as a mandatory item to prevent progression of muscle mass loss; however, diagnostic methods have extreme variation according to methodology, population, etiology and severity of liver disease. Reversing sarcopenia should be an integral therapeutic strategy. EXPERT OPINION: Clinical and nutritional interventions should be adapted to liver injury etiology and stage of disease, each of them shares a similar sarcopenia development pathway. There are specific biomarkers that condition or exacerbate loss of skeletal muscle.

Liver toxicity mechanisms of herbs commonly used in Latin America.

Mexico owns approximately 4500 medicinal plants species, a great diversity that position it at the second place after China. According to the Mexican health department, 90% of common population consumes them to treat various diseases. Additionally, herbal remedies in Latin America (LA) are considered a common practice, but the frequency of use and the liver damage related to its consumption is still unknown. Despite the high prevalence and indiscriminate herbal consumption, the exact mechanism of hepatotoxicity and adverse effects is not fully clarified and is still questioned. Some herb products associated with herb induced liver injury (HILI) are characterized by presenting a different chemical composition that may vary from batch to batch, also the biological activity of many medicinal plants and other natural products are directly related to their most active component and its concentration. There are two main biological components that are associated with liver damage, alkaloids, and flavonoids, which are frequent constituents of commonly used herbs. The interaction with the different cytochrome P-450 isoforms, inflammatory, and oxidative activities seem to be the main damage pathway involved in the liver. It is important to know the herbal adverse effects and mechanisms involved; therefore, this article is focused on the beneficial and deleterious effects as well as the possible toxicity mechanisms and interactions of the herbs that are frequently used in LA, since the herb-host interaction may not always be the expected or desired depending on the clinical context in which it is administered.

Elevated cholesterol levels have a poor prognosis in a cholestasis scenario.

Cholestasis results from defective bile flow through the biliary ducts leading to the accumulation of bile acids (BAs) in hepatocytes and serum. It has been seen that cholestasis is associated with hypercholesterolemia, which is a prerequisite for gallstone formation and primary biliary cirrhosis, being some of the most common gastrointestinal disorders in Western societies. Cytotoxic BAs induce proinflammatory mediators, oxidative stress, and apoptosis in hepatocytes, whereas cytoprotective BAs prevent them; they can also modify the plasmatic membrane structure of cells or mitochondrial outer membrane properties as well as the distribution of cholesterol, altering various proteins involved in BAs homeostasis.

Role of bioactive fatty acids in nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD) is characterized by fat deposition in hepatocytes, and a strong association with nutritional factors. Dietary fatty acids are classified according to their biochemical properties, which confer their bioactive roles. Monounsaturated fatty acids have a dual role in various human and murine models. In contrast, polyunsaturated fatty acids exhibit antiobesity, anti steatosic and anti-inflammatory effects. The combination of these forms of fatty acids-according to dietary type, daily intake and the proportion of n-6 to n-3 fats-can compromise hepatic lipid metabolism. A chemosensory rather than a nutritional role makes bioactive fatty acids possible biomarkers for NAFLD. Bioactive fatty acids provide health benefits through modification of fatty acid composition and modulating the activity of liver cells during liver fibrosis. More and better evidence is necessary to elucidate the role of bioactive fatty acids in nutritional and clinical treatment strategies for patients with NAFLD.

Mitochondrial Molecular Pathophysiology of Nonalcoholic Fatty Liver Disease: A Proteomics Approach.

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver condition that can progress to nonalcoholic steatohepatitis, cirrhosis and cancer. It is considered an emerging health problem due to malnourishment or a high-fat diet (HFD) intake, which is observed worldwide. It is well known that the hepatocytes' apoptosis phenomenon is one of the most important features of NAFLD. Thus, this review focuses on revealing, through a proteomics approach, the complex network of protein interactions that promote fibrosis, liver cell stress, and apoptosis. According to different types of in vitro and murine models, it has been found that oxidative/nitrative protein stress leads to mitochondrial dysfunction, which plays a major role in stimulating NAFLD damage. Human studies have revealed the importance of novel biomarkers, such as retinol-binding protein 4, lumican, transgelin 2 and hemoglobin, which have a significant role in the disease. The post-genome era has brought proteomics technology, which allows the determination of molecular pathogenesis in NAFLD. This has led to the search for biomarkers which improve early diagnosis and optimal treatment and which may effectively prevent fatal consequences such as cirrhosis or cancer.

The interplay between hepatic stellate cells and hepatocytes in an in vitro model of NASH.

BACKGROUND & AIM: A complex interplay exists between hepatocytes and hepatic stellate cells (HSC) in hepatic fibrogenesis. The activation of HSCs after liver injury leads to production of extracellular matrix (ECM). Co-culture models could be useful to mimic the liver microenvironment. This study evaluates the effect of free fatty acids (FFA) on HSC cells and the interplay with hepatocytes via both soluble-mediator and cell-cell contact. METHODS: The human hepatocyte cell line (HuH7) and HSC cells (LX2) were exposed to FFA for 24 h in 3 different experimental set-ups: (A) monoculture of HSC; (B) Transwell® system (effect of soluble mediators); and (C) Simultaneous Co-Culture (SCC) (cell-to-cell connections). Intracellular FFA accumulation was assessed qualitatively (microscopy) and quantitatively (flow cytometry); the activation of HSC (alpha smooth muscle actin, α-SMA) expression of ECM components were quantified by RT-PCR. RESULTS: FFA exposure induces intracellular fat accumulation in all the experimental set-up but the expression of α-SMA was significantly increased only in SCC. On the contrary, the expression of ECM was substantially decreased in the transwell® system. CONCLUSIONS: The HSC activation is independent of FFA accumulation but requires cell-to-cell interaction with hepatocyte. On the contrary, the gene regulation of ECM components seems to occur through paracrine mediators.

Vigorous, but differential mononuclear cell response of cirrhotic patients to bacterial ligands.

AIM: To study the role of gram-positive and gram-negative bacteria in the pathogenesis of liver injury, specifically the activation of inflammatory mediators. METHODS: Peripheral blood mononuclear cells of 20 out-patients were studied, 10 of them with cirrhosis. Peripheral blood mononuclear cells were isolated and exposed to lipopolysaccharide or lipoteichoic acid. CD14, Toll-like receptor 2 and 4 expression was determined by flow cytometry, and tumor necrosis factor (TNF) α, interleukin (IL)-1ß, IL-6, IL-12 and IL-10 secretion in supernatants was determined by ELISA. RESULTS: Higher CD14, Toll-like receptor 2 and 4 expression was observed in peripheral blood mononuclear cells from cirrhotic patients, (P < 0.01, P < 0.006, P < 0.111) respectively. Lipopolysaccharide and lipoteichoic acid induced a further increase in CD14 expression (P < 0.111 lipopolysaccharide, P < 0.013 lipoteichoic acid), and a decrease in Toll-like receptor 2 (P < 0.008 lipopolysaccharide, P < 0.008 lipoteichoic acid) and Toll-like receptor 4 (P < 0.008 lipopolysaccharide, P < 0.028 lipoteichoic acid) expression. With the exception of TNFα, absolute cytokine secretion of peripheral blood mononuclear cells was lower in cirrhotic patients under non-exposure conditions (P < 0.070 IL-6, P < 0.009 IL-1ß, P < 0.022 IL-12). Once exposed to lipopolysaccharide or lipoteichoic acid, absolute cytokine secretion of peripheral blood mononuclear cells was similar in cirrhotic and non-cirrhotic patients, determining a more vigorous response in the former (P < 0.005 TNFα, IL-1ß, IL-6, IL-2 and IL-10 lipopolysaccharide; P < 0.037 TNFα; P < 0.006 IL-1ß; P < 0.005 IL-6; P < 0.007 IL-12; P < 0.014 IL-10 lipoteichoic acid). Response of peripheral blood mononuclear cells was more intense after lipopolysaccharide than after lipoteichoic acid exposure. CONCLUSION: Peripheral blood mononuclear cells of cirrhotic patients are able to respond to a sudden bacterial ligand exposure, particularly lipopolysaccharide, suggesting that immune regulation mechanisms are still present.