The latest medical research on Gastroenterology
The research magnet gathers the latest research from around the web, based on your specialty area. Below you will find a sample of some of the most recent articles from reputable medical journals about gastroenterology gathered by our medical AI research bot.
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Request AccessExome-wide association analysis identifies novel risk loci for alcohol-associated hepatitis.
HepatologyAlcohol-associated hepatitis (AH) is a clinically severe, acute disease that afflicts only a fraction of patients with alcohol use disorder (AUD). Genomic studies of alcohol-associated cirrhosis (AC) have identified several genes of large effect, but the genetic and environmental factors that lead to AH and AC, and their degree of genetic overlap, remain largely unknown. This study aims to identify genes and genetic variation that contribute to the development of AH.
Exome-sequencing of patients with AH (N=784) and heavy drinking controls (N=951) identified exome-wide significant association for AH at PNPLA3, as previously observed for AC in GWAS, although with a much lower effect-size. SNPs of large effect-size at ICOSLG (Chr 21) and TOX4/RAB2B (Chr 14), were also exome-wide significant. ICOSLG encodes a co-stimulatory signal for T-cell proliferation and cytokine secretion and induces B-cell proliferation and differentiation. TOX4 was previously implicated in diabetes and immune system function. Other genes previously implicated in AC did not strongly contribute to AH, and the only prominently implicated (but not exome wide significant) gene overlapping with AUD was ADH1B. Polygenic signals for AH were observed in both common and rare variant analysis and identified genes with roles associated with inflammation.
This study has identified two new genes of high effect size with a previously unknown contribution to ALD, and highlights both the overlap in etiology between liver diseases, and the unique origins of AH.
Ag-driven CD8+ T cell clonal expansion is a prominent feature of MASH in humans and mice.
HepatologyChronic liver disease due to metabolic dysfunction-associated steatohepatitis (MASH) is a rapidly increasing global epidemic. MASH progression is a consequence of the complex interplay between inflammatory insults and dysregulated hepatic immune responses. T lymphocytes have been shown to accumulate in the liver during MASH, but the cause and consequence of T cell accumulation in the liver remain unclear. Our study aimed to define the phenotype and T cell receptor diversity of T cells from human cirrhotic livers and an animal model of MASH to begin resolving their function in disease.
In these studies, we evaluated differences in T cell phenotype in the context of liver disease. Accordingly, we isolated liver resident T cell populations from humans with cirrhosis and from mice with diet-induced MASH. Using both 5' single-cell sequencing and flow cytometry, we defined the phenotype and T cell receptor repertoire of liver resident T cells during health and disease.
MASH-induced human cirrhosis and diet-induced MASH in mice resulted in the accumulation of activated and clonally expanded T cells in the liver. The clonally expanded T cells in the liver expressed markers of chronic antigenic stimulation, including PD1, TIGIT, and TOX. Overall, this study establishes for the first time that T cells undergo Ag-dependent clonal expansion and functional differentiation during the progression of MASH. These studies could lead to the identification of antigenic targets that drive T cell activation, clonal expansion, and recruitment to the liver during MASH.
Liver transplantation provides survival benefit at all levels of frailty: From the Multicenter Functional Assessment in Liver Transplantation Study.
HepatologyOffering LT to frail patients may reduce waitlist mortality but may increase post-LT mortality. LT survival benefit is the concept of balancing these risks. We sought to quantify net survival benefit with LT by liver frailty index (LFI).
We analyzed data in the multi-center Functional Assessment in LT (FrAILT) Study from 2012-2021. Pre-LT cohort included ambulatory patients with cirrhosis awaiting LT, without hepatocellular carcinoma; post-LT cohort included those who underwent LT. Primary outcomes were pre-LT and post-LT mortality. We computed 1-, 3-, and 5-year restricted mean survival times (RMST) from adjusted Cox models. Survival benefit was calculated as net gain in life-years with LT. Pre-LT cohort included 2628 patients: median MELDNa was 18 (IQR 14-22); 731 (28%) were frail; 440 (17%) died pre-LT. Post-LT cohort included 1335 patients: median MELDNa was 20 (IQR 14-24); 325 (24%) were frail; 103 (8%) died post-LT. Pre-LT RMST decreased substantially as LFI increased. Post-LT RMST also decreased as LFI increased but only modestly. There was no LFI threshold at which pre-LT and post-LT RMST intersected-patients had net survival benefit at all LFI values.
Pre-LT and, to a lesser degree, post-LT mortality increased as LFI increased. Transplant offered a survival benefit at all LFI values, driven by a reduction in pre-LT mortality. No threshold of LFI was identified at which the risk of post-LT mortality exceeded pre-LT mortality. LT offers net survival benefit even in the presence of advanced frailty among those selected for LT.
Endothelial RUNX3 controls LSEC dysfunction and angiocrine LRG1 signaling to prevent liver fibrosis.
HepatologyLiver fibrosis represents a global health burden, given the paucity of approved antifibrotic therapies. Liver sinusoidal endothelial cells (LSECs) play a major gatekeeping role in hepatic homeostasis and liver disease pathophysiology. In early tumorigenesis, runt-related transcription factor 3 (RUNX3) functions as a sentinel; however, its function in liver fibrosis in LSECs remains unclear. This study aimed to investigate the role of RUNX3 as an important regulator of the gatekeeping functions of LSECs and explore novel angiocrine regulators of liver fibrosis.
Mice with endothelial Runx3 deficiency develop gradual and spontaneous liver fibrosis secondary to LSEC dysfunction, thereby more prone to liver injury. Mechanistic studies in human immortalized LSECs and mouse primary LSECs revealed that IL-6/JAK/STAT-3 pathway activation was associated with LSEC dysfunction in the absence of RUNX3. Single-cell RNA sequencing and quantitative RT-PCR revealed that leucine-rich alpha-2-glycoprotein 1 (LRG1) was highly expressed in RUNX3-deficient and dysfunctional LSECs. In in vitro and coculture experiments, RUNX3-depleted LSECs secreted LRG1, which activated hepatic stellate cells via TGFBR1-SMAD2/3 signaling in a paracrine manner. Furthermore, circulating LRG1 levels were elevated in mouse models of liver fibrosis and in patients with fatty liver and cirrhosis.
RUNX3 deficiency in the endothelium induces LSEC dysfunction, LRG1 secretion, and liver fibrosis progression. Therefore, endothelial RUNX3 is a crucial gatekeeping factor in LSECs, and profibrotic angiocrine LRG1 may be a novel target for combating liver fibrosis.
Choline-deficient high-fat diet-induced MASH in Göttingen Minipigs: Characterisation and effects of a chow reversal period.
Am J PhysiolThe prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH) is i...
Hepatitis E virus: from innate sensing to adaptive immune responses.
Nat Rev GastroenterolHepatitis E virus (HEV) infections are a major cause of acute viral hepatitis in humans worldwide. In immunocompetent individuals, the majority of ...
Epigenetic heterogeneity hotspots in human liver disease progression.
HepatologyDisruption of the epigenome is a hallmark of human disease including liver cirrhosis and hepatocellular carcinoma (HCC). While genetic heterogeneity is an established effector of pathologic phenotypes, epigenetic heterogeneity is less well understood. Environmental exposures alter the liver-specific DNA methylation landscape and influence the onset of liver cancer. Given that currently available treatments are unable to target frequently mutated genes in HCC, there is an unmet need for novel therapeutics to prevent or reverse liver damage leading to hepatic tumorigenesis, which the epigenome may provide. We performed genome-wide profiling of DNA methylation, copy number, and gene expression from multiple liver regions from 31 patients with liver disease to examine their crosstalk and define the individual and combinatorial contribution of these processes to liver disease progression. We identify epigenetic heterogeneity hotspots that are conserved across patients. Elevated epigenetic heterogeneity associates with increased gene expression heterogeneity. Cirrhotic regions comprise two distinct cohorts, one exclusively epigenetic, and a second where epigenetic and copy number variations collaborate. Epigenetic heterogeneity hotspots are enriched for genes central to liver function (e.g., HNF1A) and known tumor suppressors (e.g., RASSF1A). These hotspots encompass genes including ACSL1, ACSL5, MAT1A, and ELFN1, which have phenotypic effects in functional screens, supporting their relevance to hepatocarcinogenesis. Moreover, epigenetic heterogeneity hotspots are linked to clinical measures of outcome.
Substantial epigenetic heterogeneity arises early in liver disease development, targeting key pathways in the progression and initiation of both cirrhosis and HCC. Integration of epigenetic and transcriptional heterogeneity unveils putative epigenetic regulators of hepatocarcinogenesis.
Development and validation of pFIB scores for exclusion of significant liver fibrosis in pediatric MASLD.
HepatologyMetabolic dysfunction-associated steatotic liver disease (MASLD) is the most prevalent pediatric liver disease, yet accurate risk scores for referral of children/adolescents with suspected clinically significant liver fibrosis are currently lacking.
Clinical and biochemical variables were collected in a prospective cohort of 327 children and adolescents with severe obesity, in whom liver fibrosis was evaluated by transient elastography. Logistic regression was performed to establish continuous (pFIB-c) and simplified (pFIB-6) diagnostic scores that accurately exclude significant (≥F2) fibrosis. Performance for each was compared to established non-invasive fibrosis scores. These scores were validated in elastography (n=504) and multiple biopsy-proven MASLD (n=261) cohorts. Patient sex, ethnicity, weight z-score, HOMA-IR index, ALT, and presence of hypertension were included in the scores. The pFIB-c and pFIB-6 exhibited good discriminatory capacity (c-statistic of 0.839 and 0.826), outperforming existing indices. Negative predictive values (NPV) were >90% for both scores in the derivation and elastography validation cohorts. Performance in the histological cohorts varied (AUROCs for the pFIB-c between 0.710 and 0.770), as the scores were less accurate when applied to populations in tertiary referral centers characterized by a high prevalence of significant fibrosis and high ALT levels.
Analyzing several cohorts totaling approximately 1100 children and adolescents, we developed novel risk scores incorporating readily available clinical variables. In accordance with the aim of excluding pediatric MASLD-associated fibrosis, the scores performed better in non-selected cohorts of children and adolescents living with obesity than in patients referred to tertiary liver units.
Hepatic decompensation is the major driver of mortality in hepatocellular carcinoma patients treated with atezolizumab plus bevacizumab: The impact of successful antiviral treatment.
HepatologyUnlike other malignancies, hepatic functional reserve competes with tumour progression in determining the risk of mortality from hepatocellular carcinoma (HCC). However, the relative contribution of hepatic decompensation over tumour progression in influencing overall survival (OS) has not been assessed in combination immunotherapy recipients.
From the AB-real observational study(n=898), we accrued 571 patients with advanced/unresectable HCC, Child-Pugh A class treated with frontline atezolizumab+bevacizumab(AB). Hepatic decompensation and tumour progression during follow-up were studied in relationship to patients' OS using time-dependent Cox model. Baseline characteristics were evaluated as predictors of decompensation in competing risks analysis. During a median follow-up of 11.0 months (95%CI 5.1-19.7), 293 patients(51.3%) developed tumour progression without decompensation and 94(16.5%) developed decompensation. In multivariable time-dependent analysis, decompensation(hazard ratio[HR] 19.04, 95%CI 9.75-37.19), HCC progression(HR 9.91, 95%CI 5.85-16.78), albumin-bilirubin(ALBI) grade 2/3(HR 2.16, 95%CI 1.69-2.77) and number of nodules>3(HR 1.63, 95%CI 1.28-2.08) were independently associated with OS. Pre-treatment ALBI grade 2/3(subdistribution HR [sHR] 3.35, 95%CI 1.98-5.67) was independently associated with decompensation, whereas viral aetiology was protective(sHR 0.55, 95%CI 0.34-0.87). Among patients with viral aetiology, effective antiviral treatment was significantly associated with lower risk of decompensation (sHR 0.48, 95%CI 0.25-0.93).
Hepatic decompensation identifies patients with the worst prognosis following AB and is more common in patients with baseline ALBI>1 and non-viral aetiology. Effective antiviral treatment may protect from decompensation, highlighting the prognostic disadvantage of patients with non-viral aetiologies and the importance of multi-disciplinary management to maximise OS.
Acute kidney injury in severe alcohol-associated hepatitis treated with anakinra plus zinc or prednisone.
HepatologyIn a recent trial, patients with severe-alcohol-associated-hepatitis (sAH) treated with anakinra-plus-zinc (A+Z) had lower survival and higher acute-kidney-injury (AKI) rates versus prednisone (PRED). We characterize the clinical factors and potential mechanisms associated with AKI development in that trial.
Data from 147-participants in a multicenter randomized clinical trial (74 A+Z, 73 PRED) were analyzed. AKI, AKI-phenotypes, and kidney-injury biomarkers were compared between participants who did/did not develop AKI in the two treatment-arms. Multivariable competing-risk analyses were performed to identify baseline risk-factors for incident AKI, with death treated as a competing event. Risk-factors considered were age, sex, mean arterial pressure, white blood cell count, albumin, MELD, ascites, hepatic encephalopathy, and treatment arm. At baseline, no participants had AKI; 33% (n=49) developed AKI during follow-up. AKI incidence was higher in A+Z than PRED [45% (n=33) versus 22% (n=16), p=0.001]. AKI-phenotypes were similar between the two treatment-arms (p=0.361) but peak-AKI severity was greater in A+Z than PRED [stage-3 n=21 (63.6%) versus n=8 (50.0%), p=0.035]. At baseline, urine-neutrophil-gelatinase-associated-lipocalin (uNGAL) levels were similar between participants who developed AKI in both treatment-arms (p=0.319). However, day 7 and 14 uNGAL levels were significantly elevated in A+Z-treated participants who developed AKI versus PRED-treated participants who developed AKI (p=0.002 and p=0.032, respectively). On multivariable competing-risk analysis, only A+Z was independently associated with incident AKI (sHR 2.35, p=0.005).
AKI occurred more frequently and was more severe in A+Z-treated participants. A+Z-treated participants with AKI had higher uNGAL, suggesting that A+Z maybe nephrotoxic in sAH patients.
PGD2/DP1 axis promotes liver regeneration by secreting Wnt2 in Kupffer cells in mice.
HepatologyThe liver possesses a remarkable regenerative capacity in response to injuries or viral infections. Various growth factors and cytokines are involved in regulating liver regeneration. Prostaglandin (PG) D2, a pro-resolution lipid mediator, is the most abundant hepatic prostanoid. However, the role of PGD2 in the injury-induced liver regeneration remains unclear.
Two-thirds partial hepatectomy (70% PH), massive hepatectomy (85% resection), and carbon tetrachloride-induced chronic injury were performed in mice to study the mechanisms of live regeneration. Hepatic PGD2 production was elevated in mice after PH. Global deletion of D prostanoid receptor (DP) 1, but not DP2, slowed PH-induced liver regeneration in mice, as evidenced by lower liver weight to body weight ratio, less Ki67+ hepatocyte proliferation, and G2/M phase hepatocytes. Additionally, DP1 deficiency specifically in resident Kupffer cells (KCs), and not in endothelial cells or hepatic stellate cells, retarded liver regeneration in mice post-PH. Conversely, the overexpression of exogenous DP1 in KCs accelerated liver regeneration in mice. Mechanistically, DP1 activation promoted Wnt2 transcription in a PKA/CREB-dependent manner in resident KCs and mediated hepatocyte proliferation through Frizzled8/β-catenin signaling. Adeno-associated virus vector serotype 8 (AAV8)-mediated Frizzled8 knockdown in hepatocytes attenuated accelerated liver regeneration in KC-DP1 transgenic mice post-PH. Treatment with the DP1 receptor agonist BW245C promotes PH-induced liver regeneration in mice.
DP1 activation mediates crosstalk between KCs and hepatocytes through Wnt2, and facilitates liver regeneration. Hence, DP1 may serve as a novel therapeutic target in acute and chronic liver diseases.
Liver stiffness progression in biopsy-proven metabolic dysfunction-associated steatotic disease among people with diabetes versus people without diabetes: A prospective multicenter study.
HepatologyThere are limited data on the progression of liver stiffness measurement (LSM) by vibration-controlled transient elastography (VCTE) in people with type 2 diabetes (T2DM) versus those without T2DM in biopsy-proven metabolic dysfunction-associated steatotic liver disease (MASLD). We examined LSM progression in participants with T2DM versus those without T2DM in a large, prospective, multicenter cohort study.
This study included 1,231 adult participants (62% female) with biopsy-proven MASLD who had VCTEs at least one year apart. LSM progression and regression were defined by a ≥ 20% increase and an upward or downward change, respectively, in the LSM category in the Baveno VII categories for compensated advanced chronic liver disease, compared between participants with T2DM (n=680) versus no T2DM (n=551) at baseline. The mean (±SD) age and BMI were 51.8 (±12.0) years and 34.0 (±6.5) kg/m2, respectively. The median (IQR) time between the first and last VCTE measurements was 4.1(2.5-6.5) years. Participants with T2DM had higher LSM progression at 4-years (12% vs. 10%), 6-years (23% vs. 16%), and 8-years (50% vs. 39%), p=0.04. Using a multivariable Cox proportional hazards model adjusted for multiple confounders, the presence of T2DM remained an independent predictor of LSM progression (adjusted HR 1.35, 95% CI 1.01-1.81, p=0.04). T2DM was not associated with LSM regression (p=0.71). Mean HbA1c was significantly associated with LSM progression (p=0.003) and regression (p=0.02).
Utilizing serial VCTE data from a multicenter study of participants with biopsy-proven MASLD, we demonstrate that T2DM and HbA1c are associated with LSM progression.
