Are we ready for genetic testing in metabolic dysfunction-associated steatotic liver disease?

Metabolic dysfunction-associated steatotic liver disease (MASLD), with its steadily increasing prevalence, represents now a major problem in public health. A proper referral could benefit from tools allowing more precise risk stratification. To this end, in recent decades, several genetic variants that may help predict and refine the risk of development and progression of MASLD have been investigated. In this review, we aim to discuss the role genetics in MASLD plays in everyday clinical practice. We performed a comprehensive literature search of PubMed for relevant publications. Available evidence highlights the emergence of genetic-based noninvasive algorithms for diagnosing fatty liver, metabolic dysfunction-associated steatohepatitis, fibrosis progression and occurrence of liver-related outcomes including hepatocellular carcinoma. Nevertheless, their accuracy is not optimal and application in everyday clinical practice remains challenging. Furthermore, susceptible genetic markers have recently become subjects of great scientific interest as therapeutic targets in precision medicine. In conclusion, decisional algorithms based on genetic testing in MASLD to facilitate the clinician decisions on management and treatment are under growing investigation and could benefit from artificial intelligence methodology.

MAFLD: a multisystem disease

Nonalcoholic fatty liver disease (NAFLD), affecting about 25% of general population and more than 50% of dysmetabolic patients, is an emerging cause of chronic liver disease and its complications. Recently, an international consensus of experts proposed to rename this disease as 'Metabolic dysfunction-Associated Fatty Liver Disease' (MAFLD) to focus on the bidirectional interplay between fatty liver and metabolic alterations and to stress the need of assessing fatty liver independently from alcohol consumption and other coexisting causes of liver disease. The peculiarity of NAFLD/MAFLD lies in the presence of a higher risk of not only - as expected - liver-related events but also of extrahepatic events, mostly cardiovascular and cancers. Available evidence suggests that these associations are not only the expression of sharing the same risk factors but shed light about the ability of NAFLD/MAFLD and particularly of its progressive form - nonalcoholic/metabolic dysfunction-associated steatohepatitis - to act as an independent risk factor via promotion of atherogenic dyslipidemia and a proinflammatory, profibrogenic, and procoagulant systemic environment. The present review summarizes available epidemiological and clinical evidence supporting the concept of NAFLD/MAFLD as a multisystemic disease, and highlights potential explanatory mechanisms underlying the association between NAFLD/MAFLD and extrahepatic disorders.

Effect of pharmacological interventions and placebo on liver Histology in nonalcoholic steatohepatitis: A network meta-analysis

BACKGROUND

The aims of this study were to quantify the histological improvement and its risk factors in patients with NASH enrolled in the placebo arms of randomized controlled trials (RCTs), and to indirectly compare the effect of several investigational drugs for NASH on validated histological outcomes.

DATA SYNTHESIS

A comprehensive search was conducted to detect phase 2 and 3 RCTs comparing pharmacological interventions in patients with NASH. According to Food and Drug Administration (FDA) recommendations, primary outcomes included: 1) NASH resolution without worsening of fibrosis; 2) At least 1-point reduction in fibrosis without worsening of NASH. Meta-analysis and meta-regressions were conducted on placebo arms, while network meta-analysis was performed on intervention arms. A total of 15 RCTs met the eligibility criteria. The meta-analysis on placebo arms showed a pooled estimate rate of 17% (95%C.I. 12%-23%;I² = 86%; p < 0.01) for NASH resolution without worsening of fibrosis and of 21% (95%C.I. 13%-31%;I² = 84%; p < 0.01) for ≥1stage improvement of fibrosis without worsening of NASH. Phase 3 (vs Phase 2)RCTs, older age and higher AST levels were significantly associated with progression of liver disease by univariate meta-regression. At network meta-analysis, Semaglutide (P-score 0.906), Pioglitazione alone (score 0.890) and plus Vitamin E (0.826) had the highest probability of being ranked the most effective intervention for NASH resolution without worsening of fibrosis, while Aldafermin (0.776), Lanifibranor (0.773) and Obeticholic acid (0.771) had the highest probability to achieve ≥1 stage of fibrosis improvement without worsening of NASH.

CONCLUSION

This study confirms the heterogeneity of histological progression of untreated patients with NASH and provides evidence to stratify patients according to identified risk factors in future RCTs of combination therapies. PROSPERO CRD42021287205.