The pathogenic mechanisms underlying the progression of non-alcoholic fatty liver disease (NAFLD) are not fully understood. In this study, we aimed to assess the relationship between endoplasmic reticulum (ER) stress and autophagy in human and mouse hepatocytes during NAFLD. ER stress and autophagy markers were analyzed in livers from patients with biopsy-proven non-alcoholic steatosis (NAS) or non-alcoholic steatohepatitis (NASH) compared with livers from subjects with histologically normal liver, in livers from mice fed with chow diet (CHD) compared with mice fed with high fat diet (HFD) or methionine-choline-deficient (MCD) diet and in primary and Huh7 human hepatocytes loaded with palmitic acid (PA). In NASH patients, significant increases in hepatic messenger RNA levels of markers of ER stress (activating transcription factor 4 (ATF4), glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP)) and autophagy (BCN1) were found compared with NAS patients. Likewise, protein levels of GRP78, CHOP and p62/SQSTM1 (p62) autophagic substrate were significantly elevated in NASH compared with NAS patients. In livers from mice fed with HFD or MCD, ER stress-mediated signaling was parallel to the blockade of the autophagic flux assessed by increases in p62, microtubule-associated protein 2 light chain 3 (LC3-II)/LC3-I ratio and accumulation of autophagosomes compared with CHD fed mice. In Huh7 hepatic cells, treatment with PA for 8 h triggered activation of both unfolding protein response and the autophagic flux. Conversely, prolonged treatment with PA (24 h) induced ER stress and cell death together with a blockade of the autophagic flux. Under these conditions, cotreatment with rapamycin or CHOP silencing ameliorated these effects and decreased apoptosis. Our results demonstrated that the autophagic flux is impaired in the liver from both NAFLD patients and murine models of NAFLD, as well as in lipid-overloaded human hepatocytes, and it could be due to elevated ER stress leading to apoptosis. Consequently, therapies aimed to restore the autophagic flux might attenuate or prevent the progression of NAFLD.
Measurements of portal pressure, usually obtained via the hepatic venous pressure gradient (HVPG) may be a prognostic marker in cirrhosis. The aim of this study was to evaluate the impact of HVPG on survival in patients with cirrhosis in addition to the Model for EndStage Liver Disease (MELD) score. We also examined whether inclusion of HVPG in a model with MELD variables improves its prognostic ability. Retrospective analyses of all patients who had HVPG measurements between January 1998 and December 2002 were considered. Proportional hazards Cox models were developed. Prognostic calibrative and discriminative ability of the model was evaluated. In this period, 693 patients had a hepatic hemodynamic study, and 393 patients were included. Survival was significantly worse in those patients with greater HVPG value (univariate HR, 1.05; 95% CI, 1.02-1.08; P ؍ .001). HVPG remained as an independent variable in a model adjusted by MELD, ascites, encephalopathy, and age (multivariate HR, 1.03; 95% CI, 1.00-1.06; P ؍ .05) so that each 1-mmHg increase in HVPG had a 3% increase in death risk. In addition, HVPG as well as MELD score variables and age, significantly contributes to the calibrative predictive capacity of the prognostic model; however, discriminative ability improved only slightly (overall C statistic T he Model for End-Stage Liver Disease (MELD) score, initially developed for survival prediction of patients undergoing the transjugular intrahepatic portal systemic shunt (TIPS) procedure, 1 has been subsequently validated in an increasingly heterogeneous population of patients with cirrhosis as a very good tool to rank patients according to their short-term risk of death. [2][3][4][5] In the initial validation of the MELD score, individual complications of portal hypertension (ascites, spontaneous bacterial peritonitis, variceal bleeding, and encephalopathy) were added to the model, producing only minimal improvement in its discriminative ability. 2 However, each individual portal hypertensionrelated complication is only one aspect of the underlying pathophysiological mechanism, the portal hypertensive syndrome. Re-evaluation of the role of portal hypertension indexes in such predictive scores has been suggested, as portal hypertension has been described as the third parameter most frequently found to be a significant predictor of survival in cirrhosis. 6 Interestingly, after dividing patients in categories according to MELD score, 1-year mortality within each category was higher among patients with portal hypertension-related complications.
Objectives:Treatment for celiac disease (CD) is a lifelong strict gluten-free diet (GFD). Patients should be followed-up with dietary interviews and serology as CD markers to ensure adherence to the diet. However, none of these methods offer an accurate measure of dietary compliance. Our aim was to evaluate the measurement of gluten immunogenic peptides (GIP) in stools as a marker of GFD adherence in CD patients and compare it with traditional methods of GFD monitoring.Methods:We performed a prospective, nonrandomized, multicenter study including 188 CD patients on GFD and 84 healthy controls. Subjects were given a dietary questionnaire and fecal GIP quantified by enzyme-linked immunosorbent assay (ELISA). Serological anti-tissue transglutaminase (anti-tTG) IgA and anti-deamidated gliadin peptide (anti-DGP) IgA antibodies were measured simultaneously.Results:Of the 188 celiac patients, 56 (29.8%) had detectable GIP levels in stools. There was significant association between age and GIP in stools that revealed increasing dietary transgressions with advancing age (39.2% in subjects ≥13 years old) and with gender in certain age groups (60% in men ≥13 years old). No association was found between fecal GIP and dietary questionnaire or anti-tTG antibodies. However, association was detected between GIP and anti-DGP antibodies, although 46 of the 53 GIP stool-positive patients were negative for anti-DGP.Conclusions:Detection of gluten peptides in stools reveals limitations of traditional methods for monitoring GFD in celiac patients. The GIP ELISA enables direct and quantitative assessment of gluten exposure early after ingestion and could aid in the diagnosis and clinical management of nonresponsive CD and refractory CD. Trial registration number NCT02711397.
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