The latest medical research on Gastroenterology

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Non-invasive liver disease assessment to identify portal hypertension: A systematic review supporting the AASLD Practice Guideline.

Hepatology

Portal hypertension is a serious complication of cirrhosis, which leads to life-threatening complications. Hepatic venous pressure gradient (HVPG), a surrogate of portal pressure, is the reference standard test to assess the severity of portal hypertension. However, since HVPG is limited by its invasiveness and by its availability, non-invasive liver disease assessments (NILDAs) to assess portal pressure, especially clinically significant portal hypertension (CSPH), are needed.

We conducted a systematic review of Ovid MEDLINE(R) and Epub Ahead of Print, In-Process & Other Non-Indexed Citations, and Daily, Ovid EMBASE, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, and Scopus from each database's inception to April 22nd, 2022. We included only studies in English that examined ≥50 patients in single liver disease etiologies which compared non-invasive tests (blood, and/or imaging) to HVPG for predicting clinically significant portal hypertension (CSPH; defined as HVPG ≥10 mm Hg) in patients with chronic liver disease (this therefore limited the number of studies that could be included). Outcomes reported included measures of diagnostic test accuracy. Additionally, a narrative review of studies not eligible for the systematic review is also provided.

Nine studies with 2,492 patients met the inclusion criteria. There was substantial heterogeneity with regard to liver disease studied and cutoff values used to detect CSPH. Blood based tests, including aspartate to platelet ratio index (APRI) (56% sensitivity and 68% specificity) and fibrosis-4 (FIB-4) (54% sensitivity and 73% specificity) had low accuracy measures. Imaging based tests (transient elastography (TE) and shear wave elastography detection of liver stiffness (LSM)) had better accuracy, but also had substantial variation; at 15 kPa, TE sensitivity was 90%-96% and specificity was 48%-50% while at 25 kPa, its sensitivity and specificity were 57%-85% and 82%-93%, respectively. The narrative review suggested that imaging based tests are the best available NILDA to detect CSPH, CSPH is highly unlikely to be present at an LSM ≤15 kPa and likely to be present at an LSM ≥25 kPa.

While imaging-based NILDA appeared to have higher accuracy than blood-based tests to detect CSPH, only 9 studies fit the a priori established inclusion criteria for the SR. In addition, there was substantial study heterogeneity and variation in cutoffs for LSM to detect CSPH, limiting the ability to establish definitive cutoffs to detect CSPH.

Accuracy of blood-based biomarkers for staging liver fibrosis in chronic liver disease: A systematic review supporting the AASLD Practice Guideline.

Hepatology

Blood-based biomarkers have been proposed as an alternative to liver biopsy for non-invasive liver disease assessment (NILDA) in chronic liver disease (CLD). Our aims for this systematic review were to evaluate the diagnostic utility of selected blood-based tests either alone, or in combination, for identifying significant fibrosis (F2-4), advanced fibrosis (F3-4) and cirrhosis (F4), as compared to biopsy in CLD.

We included a comprehensive search of databases including Ovid MEDLINE(R), EMBASE, Cochrane Database, and Scopus through to April 2022. Two independent reviewers selected 286 studies with 103,162 patients. The most frequently identified studies included the simple aminotransferase-to-platelet ratio index (APRI) and fibrosis (FIB)-4 markers (with low-to-moderate risk of bias) in hepatitis B virus (HBV) and C virus (HCV), HIV-HCV/HBV co-infection, and nonalcoholic fatty liver disease (NAFLD). Positive (LR+) and negative (LR) likelihood ratios across direct and indirect biomarker tests for HCV and HBV for F2-4, F3-4, or F4 were 1.66-6.25 and 0.23-0.80, 1.89-5.24 and 0.12-0.64, and 1.32-7.15 and 0.15-0.86 respectively; LR+ and LR for NAFLD F2-4, F3-4 and F4 were 2-65-3.37 and 0.37-0.39, 2.25-6.76 and 0.07-0.87, and 3.90 and 0.15 respectively. Overall, proportional odds ratio indicated FIB-4 <1.45 was better than APRI <0.5 for F2-4. FIB-4 >3.25 was also better than APRI >1.5 for F3-4 and F4. There was limited data for combined tests.

Blood-based biomarkers are associated with small-to-moderate change in pre-test probability for diagnosing F2-4, F3-4, and F4 in viral hepatitis, HIV-HCV co-infection, and NAFLD, with limited comparative or combination studies for other CLD.

Imaging-based non-invasive liver disease assessment for staging liver fibrosis in chronic liver disease: A systematic review supporting the AASLD Practice Guideline.

Hepatology

Transient elastography (TE), shear-wave elastography (SWE), and/or magnetic resonance elastography (MRE), each providing liver stiffness measurement (LSM), are the most studied imaging-based noninvasive liver disease assessment (NILDA) techniques. To support the American Association for the Study of Liver Diseases guidelines on NILDA, we summarized the evidence on the accuracy of these LSM methods to stage liver fibrosis (F).

A comprehensive search for studies assessing LSM by TE, SWE, or MRE for the identification of significant fibrosis (F2-4), advanced fibrosis (F3-4), or cirrhosis (F4), utilizing histopathology as standard of reference by liver disease etiology in adults or children from inception to April 2022 was performed. We excluded studies with <50 patients with a single disease entity and mixed liver disease etiologies (with the exception of HCV/HIV co-infection). Out of 9447 studies, 240 with 61,193 patients were included in this systematic review. In adults, sensitivities for the identification of F2-4 ranged from 51% to 95%, for F3-4 from 70% to 100%, and for F4 from 60% to 100% across all techniques/diseases, whereas specificities ranged from 36% to 100%, 74% to 100%, and 67% to 99%, respectively. The largest body of evidence available was for TE; MRE appeared to be the most accurate method. Imaging-based NILDA outperformed blood-based NILDA in most comparisons, particularly for the identification of F3-4/F4. In the pediatric population, imaging-based NILDA is likely as accurate as in adults.

LSM from TE, SWE, and MRE show acceptable to outstanding accuracy for the detection of liver fibrosis across various liver disease etiologies. Accuracy increased from F2-4 to F3-4 and was the highest for F4. Further research is needed to better standardize the use of imaging-based NILDA, particularly in pediatric liver diseases.

Cell senescence in liver diseases: pathological mechanism and theranostic opportunity.

Nat Rev Gastroenterol

The liver is not oblivious to the passage of time, as ageing is a major risk factor for the development of acute and chronic liver diseases. Ageing...

Future direction of total neoadjuvant therapy for locally advanced rectal cancer.

Nat Rev Gastroenterol

Despite therapeutic advancements, disease-free survival and overall survival of patients with locally advanced rectal cancer have not improved in m...

Screening for liver fibrosis: lessons from colorectal and lung cancer screening.

Nat Rev Gastroenterol

Many countries have incorporated population screening programmes for cancer, such as colorectal and lung cancer, into their health-care systems. Ci...

Feasibility of hepatitis C elimination by screening and treatment alone in high-income countries.

Hepatology

Despite the availability of highly effective direct-acting antiviral therapy, chronic hepatitis C (CHC) continues to cause a major public health burden. In many high-income countries, treatment rates have been declining, which was exacerbated by the impact of the COVID-19 pandemic, threatening the ability to meet the World Health Organization (WHO)'s targets for eliminating hepatitis C virus (HCV) as a public health threat by 2030. We sought to model the impact of CHC in Canada, a resource-rich country with ongoing immigration from HCV-endemic regions; which relies exclusively on risk-based screening for case identification.

We developed an agent-based model to characterize the HCV epidemic in a high-income country with ongoing immigration. Combinations of prevention such as harm-reduction, screening, and treatment strategies were considered. Model parameters were estimated from the literature and calibrated against historical HCV data. Sensitivity analyses were performed to assess uncertainty. Under the current status quo of risk-based screening, we predict the incidence of CHC-induced decompensated cirrhosis, hepatocellular carcinoma, and liver-related deaths would decrease by 79.4%, 76.1%, and 62.1%, respectively, between 2015-2030, but CHC incidence would only decrease by 11.1%. Results were sensitive to HCV transmission rate and annual number of people initiating treatment.

Current risk-based screening, and subsequent treatment, will be inadequate to achieve WHO goals. With extensive scale-up in screening, and treatment, the mortality target may be achievable, but the target for preventing new CHC cases is unlikely reachable, highlighting the importance of developing enhanced harm-reduction strategies for HCV elimination.

Safety and efficacy of off-label bulevirtide monotherapy in HDV patients with decompensated Child-B cirrhosis - a real world case series.

Hepatology

Chronic hepatitis D is the most debilitating form of viral hepatitis frequently progressing to cirrhosis and subsequent decompensation. However, the HDV entry inhibitor bulevirtide is only approved for antiviral treatment of patients with compensated disease. We aimed for the analysis of real-world data on the off-label use of bulevirtide in the setting of decompensated liver cirrhosis.

We conducted a retrospective study in HDV-patients with decompensated liver disease at German, Austrian and Italian centers. We included 19 patients (47% male, mean age: 51 y) with liver cirrhosis Child-Pugh B. Median MELD score was 12 (range 9-17) at treatment initiation. Median observation period was 41 weeks. Virologic response was achieved in 74% and normal ALT was observed in 74%. Combined response was achieved by 42%. The most relevant adverse events included self-limited ALT flares, an asymptomatic increase in bile acids and need for liver transplantation. Despite bile acid increases adverse events were considered unrelated. Clinical and laboratory improvement from Child-Pugh B to A occurred in 47% (n=9/19). Improvements in the amount of ascites were observed in 58% of patients initially presenting with ascites (n=7/12).

This report on off-label bulevirtide treatment in patients with decompensated HDV cirrhosis shows similar virologic and biochemical response rates as observed in compensated liver disease. Significant improvements were observed on surrogates of hepatic function and portal hypertension. However, this improvement was not seen in all patients. Controlled trials are needed to confirm safety and efficacy of bulevirtide in decompensated HDV-cirrhosis.

Impact of clonal hematopoiesis of indeterminate potential on hepatocellular carcinoma in individuals with steatotic liver disease.

Hepatology

Metabolic dysfunction associated steatotic liver disease (MASLD) is a global epidemic and is the most rapidly rising cause of hepatocellular carcinoma (HCC). Clonal hematopoiesis of indeterminate potential (CHIP) contributes to neoplastic and cardiometabolic disorders and is considered a harbinger of tissue inflammation. CHIP was recently associated with increased risk of liver disease. The aim of this study was to examine whether CHIP is associated with HCC development in patients with SLD.

We considered individuals with MASLD-HCC (n=208) and controls with (n=414) and without (n=259) advanced fibrosis who underwent whole exome sequencing. CHIP was diagnosed when ≥2 variant callers identified a known myeloid mutation with VAF ≥2%.

CHIP was observed in 116 participants (13.1%), most frequently in DNMT3A, TET2, TP53 and ASXL1, and correlated with age (p<0.0001) and advanced liver fibrosis (p=0.001). Higher AST levels predicted non-DNMT3A-CHIP, in particular with variant allele frequency (VAF)≥10% (OR 1.14, 1.03-1.28 and OR 1.30, 1.12-1.49, respectively, p<0.05). After adjustment for sex, diabetes and a polygenic risk score of inherited MASLD predisposition CHIP was associated with cirrhosis (2.00, 1.30-3.15, p=0.02), and with HCC even after further adjustment for cirrhosis (OR 1.81, 1.11-2.00, 1.30-3.15, p=0.002). Despite the strong collinearity among aging and development of CHIP and HCC, non-DNTM3A-CHIP and TET2 lesions remained associated with HCC after full correction for clinical/genetics covariates and age (OR 2.45, 1.35-4.53; OR 4.8, 1.60-17.0, p=0.02).

We observed an independent association between CHIP, particularly related to non-DNTM3A and TET2 genetic lesions, and MASLD-HCC.

Albumin promoter-driven FlpO expression induces efficient genetic recombination in mouse liver.

Am J Physiol

Tissue-specific gene manipulations are widely used in genetically engineered mouse models. A single recombinase system, such as the one using Alb-Cre, has been commonly used for liver-specific genetic manipulations. However, most diseases are complex, involving multiple genetic changes and various cell types. A dual recombinase system is required for conditionally modifying different genes sequentially in the same cell or inducing genetic changes in different cell types within the same organism.

A FlpO cDNA was inserted between the last exon and 3'-UTR of the mouse albumin gene in a bacterial artificial chromosome (BAC-Alb-FlpO). The founders were crossed with various reporter mice to examine the efficiency of recombination. Liver cancer tumorigenesis was investigated by crossing the FlpO mice with FSF-KrasG12D mice and p53frt mice (KPF mice).

BAC-Alb-FlpO mice exhibited highly efficient recombination capability in both hepatocytes and intrahepatic cholangiocytes. No recombination was observed in the duodenum and pancreatic cells. BAC-Alb-FlpO-mediated liver-specific expression of mutant KrasG12D and conditional deletion of p53 gene caused the development of liver cancer. Remarkably, liver cancer in these KPF mice manifested a distinctive mixed hepatocellular carcinoma and cholangiocarcinoma phenotype.

A highly efficient and liver-specific BAC-Alb-FlpO mouse model was developed. In combination with other Cre lines, different genes can be manipulated sequentially in the same cell, or distinct genetic changes can be induced in different cell types of the same organism.

Group 3 innate lymphoid cells in intestinal health and disease.

Nat Rev Gastroenterol

The gastrointestinal tract is an immunologically rich organ, containing complex cell networks and dense lymphoid structures that safeguard this lar...

Pediatric acute liver failure: Current perspective in etiology and management.

Indian Journal of Gastroenterology

Pediatric acute liver failure (PALF) is a catastrophic clinical condition with very high morbidity and mortality without early detection and interv...