Liver fibrosis is critical for liver-related outcomes and mortality in chronic liver disease, irrespective of etiology, including nonalcoholic fatty liver disease (NAFLD). NAFLD has been viewed as an independent correlate of cardiovascular risk. This review article briefly describes the cellular and molecular pathomechanisms underlying hepatic fibrosis. We then address noninvasive assessment of liver fibrosis. Finally, we discuss published evidence supporting fibrosis biomarkers’ role in assessing cardiovascular risk among patients with NAFLD. While histological assessment is the diagnostic standard of hepatic fibrosis, we specifically address noninvasive techniques, including equations based on anthropometric parameters, laboratory indices, and elastometry obtained with imaging techniques. The former group includes AST: ALT ratio, the Forns Index, the AST-to-platelet ratio index score, BARD (BMI, AAR, Diabetes) score, the fibrosis-4 index (FIB-4), the NAFLD fibrosis score, the gamma-glutamyl transferase-to-platelet ratio, and the Hepamet fibrosis score. The latter comprises elastographic techniques associated with ultrasonography or magnetic resonance. Our literature review identified numerous studies demonstrating that biomarkers of fibrosis (the most common being FIB-4) and elastographic techniques predict overall mortality and major cardiovascular events among NAFLD patients. The mechanisms accounting for this association are briefly reviewed. In addition to assessing hepatic fibrosis at baseline, during follow-up, and after therapeutic interventions in NAFLD patients, noninvasive assessment of hepatic fibrosis may predict cardiovascular events and overall mortality in these patients.

Mechanobiology is a rapidly emerging field focused on the biological impact of physical forces at the molecular, cellular, and tissue level. Living cells perceive mechanical cues and transform them into biochemical signals through mechanotransduction. Mechanotransduction is a complex process that involves mechanosensors (which are located in the plasma membrane or within the cell) and mechanotransmission to the nucleus (which occurs either by physical connection between the mechanosensor and the nucleus or by mechanosignaling through biochemical pathways). Essential biological functions, including development, growth, motility, and metabolism, depend on the mechanoresponses generated by these events. Multiple lines of evidence indicate that disruption of mechanical homeostasis may contribute to the pathogenesis of nonalcoholic fatty liver disease (NAFLD), a highly prevalent metabolic disorder characterized by abnormal accumulation of lipid droplets in hepatocytes (steatosis) and often associated with inflammation and liver cell injury (steatohepatitis). While predicting individual predisposition to adverse outcomes in NAFLD remains a challenge, there is increasing evidence that steatosis and steatohepatitis trigger mechanoresponses that contribute to the early stages of pathogenesis in NAFLD and critically impact disease progression. Lipid accumulation and lipotoxicity modify liver viscoelasticity, alter the biomechanics of liver sinusoids, and initiate aberrant pathways of mechanotransduction in hepatocytes and non-parenchymal liver cells, such as sinusoidal endothelial cells and hepatic stellate cells. Interactions of these cells at mechanical interfaces with each other, with extracellular matrix, and with sinusoidal blood flow are profoundly altered by steatosis and steatohepatitis; such changes may promote a pro-angiogenic and pro-fibrotic milieu. A better understanding of liver mechanobiology may facilitate the identification of novel molecular and cellular targets in the management of NAFLD.

Highlights

● Cellular and molecular behavior is regulated by a variety of physical forces;

● Viscoelastic properties of the liver are altered in nonalcoholic fatty liver disease (NAFLD);

● Sinusoidal hemostasis is disrupted by early functional and structural changes in NAFLD;

● Mechanical cues are likely to contribute to all aspects of NAFLD pathogenesis.

The persistence of Covid-19 infection for more than four weeks after the acute phase is defined as the long Covid-19 syndrome. This condition, otherwise defined by the persistence of signs and symptoms for more than 12 weeks, shares several features with diabetes mellitus: diabetes mellitus and Covid-19 infections have a pandemic dimension, are characterized by an inflammatory milieu, and show a bidirectional relationship. Diabetic patients appear more likely to develop long Covid-19 syndrome than non-diabetic individuals. The chronicity of Covid-19 favors the development of new cases of diabetes. In this short review, we discuss the evidence supporting the link between Covid-19 and diabetes mellitus, focusing on the epidemiological and pathophysiological aspects of this dangerous relationship.

Highlights

● Patients affected by diabetes both type 1 and type 2 seem more likely to develop a long Covid-19 syndrome compared to non-diabetic subjects;

● Long Covid-19 syndrome is associated with new-onset cases of diabetes, both type 1 and type 2 higher than expected;

● Presence of other comorbidities prior to acute Covid-19 infection favors the development of long Covid-19 syndrome;

● Most frequent symptoms of long Covid-19 in diabetic patients are fatigue, shortness of breath, neurocognitive and neurological manifestations, and cardiovascular sequelae;

● Long Covid-19 can exacerbate microvascular dysfunction in patients with diabetes.

Primary liver cancer (PLC) is a heterogeneous group of disorders arising with the background of chronic liver disease (CLD) owing to varying etiologies. PLC carries a high lethality rate and a substantial epidemiological, clinical, and financial burden, which is projected to escalate. The two most common PLC histotypes in adults are hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC); the latter is sub-classified as either intrahepatic CC or extrahepatic CC. Over recent decades, there has been a decline of viral CLD accompanied by an increase in dysmetabolic CLD, resulting in PLC becoming relatively more common in Western countries. Metabolic co-morbidities are risk factors and co-factors for HCC and (increasingly) CC. Complex immunological, cellular, pro-inflammatory, molecular, and genetic processes in the systemic dysmetabolic milieu increase PLC risk. Improved understanding of these mechanisms requires close surveillance and early diagnosis of at-risk patients while paving the way for personalized medicine, chemoprevention, and innovative management of metabolic PLC.