Noninvasive Tests (NITs) for Hepatic Fibrosis in Fatty Liver Syndrome

FIB-4 Reliability in Patients With Severe Obesity: Lower Cutoffs Needed?

BACKGROUND

Liver biopsy is the gold standard to evaluate hepatic fibrosis; however, it has many drawbacks, especially in patients with severe obesity. Noninvasive testing such as the FIB-4 score is increasingly being used as the initial screening tool to identify patients at risk for advanced fibrosis. The broader applicability of FIB-4 and the precision of its cutoff values remain uncertain in metabolic dysfunction-associated steatotic liver disease and patients with severe obesity. Our study explored the correlation between FIB-4 scores and intraoperative liver biopsy in patients with severe obesity undergoing bariatric surgery.

METHODS

A total of 632 patients with severe obesity underwent preoperative vibration-controlled transient elastography and intraoperative liver biopsy during bariatric surgery from January 2020 to August 2021. Variables collected included patient demographics, laboratory values, abdominal ultrasound, vibration-controlled transient elastography, and liver biopsy results. ANOVA 1-way test, χ 2 tests, and Fisher exact tests were used for quantitative and qualitative variables, respectively. The 95% CIs for the mean FIB-4 scores were used to generate surrogate cutoff values. The proposed FIB-4 cutoffs for F0-1, F2, F3, and F4 were 0.62 (CI: 0.59, 0.64), 0.88 (0.74, 1.01), 1.24 (0.94, 1.54), and 1.53 (0.82, 2.24), respectively. Area under the curve (AUC) methods were used to compare traditional to proposed cutoff values.

RESULTS

Applying the traditional FIB-4 cutoffs to approximate advanced fibrosis yielded an AUC of 0.5748. Use of the proposed FIB-4 cutoffs increased the AUC to 0.6899. The proposed FIB-4 cutoffs correctly identified 40 patients with biopsy-proven advanced fibrosis (F3-F4), all of which would have been missed using traditional cutoffs.

CONCLUSION

Our study revealed that the use of the currently accepted FIB-4 cutoffs as the screening modality for identifying patients with advanced fibrosis due to metabolic dysfunction-associated steatotic liver disease is insufficient and will result in missing patients with histologically confirmed advanced fibrosis. Use of the revised FIB-4 scores should be considered to diagnose patients with severe obesity at high risk of liver disease progression.

Prognostication in NAFLD: physiological bases, clinical indicators, and newer biomarkers

Non-alcoholic fatty liver disease (NAFLD) is becoming an epidemic in Western countries. Notably, while the majority of NAFLD patients will not evolve until advanced liver disease, a minority of them will progress towards liver-related events. Therefore, risk stratification and prognostication are emerging as fundamental in order to optimize human and economic resources for the care of these patients.Liver fibrosis has been clearly recognized as the main predictor of poor hepatic and extrahepatic outcomes. However, a prediction based only on the stage of fibrosis is near-sighted and static, as it does not capture the propensity of disease to further progress, the speed of progression and their changes over time. These determinants, which result from the interaction between genetic predisposition and acquired risk factors (obesity, diabetes, etc.), express themselves in disease activity, and can be synthesized by biomarkers of hepatic inflammation and fibrogenesis.In this review, we present the currently available clinical tools for risk stratification and prognostication in NAFLD specifically with respect to the risk of progression towards hard hepatic outcomes, i.e., liver-related events and death. We also discuss about the genetic and acquired drivers of disease progression, together with the physiopathological bases of their come into action. Finally, we introduce the most promising biomarkers in the direction of repeatedly assessing disease activity over time, mainly in response to future therapeutic interventions.

Global prevalence of non-alcoholic fatty liver disease in type 2 diabetes mellitus: an updated systematic review and meta-analysis

INTRODUCTION

Non-alcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease, with type 2 diabetes mellitus (T2DM) as a major predictor. Insulin resistance and chronic inflammation are key pathways in the pathogenesis of T2DM leading to NAFLD and vice versa, with the synergistic effect of NAFLD and T2DM increasing morbidity and mortality risks. This meta-analysis aims to quantify the prevalence of NAFLD and the prevalence of clinically significant and advanced fibrosis in people with T2DM.

METHODS

MEDLINE and Embase databases were searched from inception until 13 February 2023. The primary outcomes were the prevalence of NAFLD, non-alcoholic steatohepatitis (NASH) and fibrosis in people with T2DM. A generalised linear mixed model with Clopper-Pearson intervals was used for the analysis of proportions with sensitivity analysis conducted to explore heterogeneity between studies.

RESULTS

156 studies met the inclusion criteria, and a pooled analysis of 1 832 125 patients determined that the prevalence rates of NAFLD and NASH in T2DM were 65.04% (95% CI 61.79% to 68.15%, I2=99.90%) and 31.55% (95% CI 17.12% to 50.70%, I2=97.70%), respectively. 35.54% (95% CI 19.56% to 55.56%, I2=100.00%) of individuals with T2DM with NAFLD had clinically significant fibrosis (F2-F4), while 14.95% (95% CI 11.03% to 19.95%, I2=99.00%) had advanced fibrosis (F3-F4).

CONCLUSION

This study determined a high prevalence of NAFLD, NASH and fibrosis in people with T2DM. Increased efforts are required to prevent T2DM to combat the rising burden of NAFLD.

PROSPERO REGISTRATION NUMBER

CRD42022360251.

Advances in Noninvasive Biomarkers for Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) currently represents one of the most common liver diseases worldwide. Early diagnosis and disease staging is crucial, since it is mainly asymptomatic, but can progress to nonalcoholic steatohepatitis (NASH) or cirrhosis or even lead to the development of hepatocellular carcinoma. Over time, efforts have been put into developing noninvasive diagnostic and staging methods in order to replace the use of a liver biopsy. The noninvasive methods used include imaging techniques that measure liver stiffness and biological markers, with a focus on serum biomarkers. Due to the impressive complexity of the NAFLD's pathophysiology, biomarkers are able to assay different processes involved, such as apoptosis, fibrogenesis, and inflammation, or even address the genetic background and "omics" technologies. This article reviews not only the currently validated noninvasive methods to investigate NAFLD but also the promising results regarding recently discovered biomarkers, including biomarker panels and the combination of the currently validated evaluation methods and serum markers.

The Non-Invasive Ultrasound-Based Assessment of Liver Viscosity in a Healthy Cohort

Liver fibrosis is the most significant prognostic factor in chronic liver disease (CLD). Clinical practice guidelines recommend the use of non-invasive techniques, such as two-dimensional shear-wave elastography (2D-SWE), to assess liver stiffness as a marker of fibrosis. Several other factors influence liver stiffness in addition to liver fibrosis. It is presumed that changes due to necro-inflammation modify the propagation of shear waves (dispersion). Therefore, new imaging techniques that investigate the dispersion properties of shear waves have been developed, which can serve as an indirect method of measuring liver viscosity (Vi PLUS). Defining the reference values in healthy subjects among different age groups and genders and analyzing the factors that influence these values is essential. However, published data on liver viscosity are still limited. This is the first study that aimed to assess the normal range of liver viscosity values in subjects with healthy livers and analyze the factors that influence them. One hundred and thirty-one consecutive subjects with healthy livers were enrolled in this prospective study. The results showed that Vi PLUS is a highly feasible method. Liver stiffness, age and BMI influenced the liver viscosity values. The mean liver viscosity by Vi PLUS in subjects with healthy livers was 1.59 Pa·s.

De novo and recurrence of metabolic dysfunction-associated fatty liver disease after liver transplantation

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a new acronym adopted from the consensus of international experts. Given the increasing prevalence of MAFLD in pre-transplant settings, de novo and recurrent graft steatosis/MAFLD are common in post-transplant settings. The impact of graft steatosis on long-term outcomes is unclear. The current knowledge of incidence rate, risk factors, diagnosis, long-term outcomes, and management of graft steatosis (both de novo and recurrent) is discussed in this review.

Mitochondrial Mutations and Genetic Factors Determining NAFLD Risk

NAFLD (non-alcoholic fatty liver disease) is a widespread liver disease that is often linked with other life-threatening ailments (metabolic syndrome, insulin resistance, diabetes, cardiovascular disease, atherosclerosis, obesity, and others) and canprogress to more severe forms, such as NASH (non-alcoholic steatohepatitis), cirrhosis, and HCC (hepatocellular carcinoma). In this review, we summarized and analyzed data about single nucleotide polymorphism sites, identified in genes related to NAFLD development and progression. Additionally, the causative role of mitochondrial mutations and mitophagy malfunctions in NAFLD is discussed. The role of mitochondria-related metabolites of the urea cycle as a new non-invasive NAFLD biomarker is discussed. While mitochondria DNA mutations and SNPs (single nucleotide polymorphisms) canbe used as effective diagnostic markers and target for treatments, age and ethnic specificity should be taken into account.

Diversity in NAFLD: A Review of Manifestations of Nonalcoholic Fatty Liver Disease in Different Ethnicities Globally

Globally, the rise in prevalence of obesity and metabolic syndrome as a whole has been linked to increased access to processed foods, such as refined sugars and saturated fats. Consequently, nonalcoholic fatty liver disease (NAFLD) is on the rise in both developed and developing nations. However, much is still unknown on the NAFLD phenotype with regards to the effect of ethnic diversity. Despite similarities in dietary habits, it appears that certain ethnicities are more protected against NAFLD than others. However, manifestations of the same genetic polymorphisms in different groups of people increase those individuals' predisposition to NAFLD. Diets from different regions have been associated with a lower prevalence of NAFLD and have even been linked to regression of hepatic steatosis. Socioeconomic variations amongst different regions of the world also contribute to NAFLD prevalence and associated complications. Thus, a thorough understanding of ethnic variability in NAFLD is essential to tailoring treatment recommendations to patients of different backgrounds.