Lay Summaries - Volume 73 Issue 3
Lay Summary: Non-alcoholic fatty liver disease is a common disease where excessive fat accumulates in the liver and may result in cirrhosis. To understand who is at risk of developing this disease and suffering liver damage, we undertook a genetic study to compare the genetic profiles of people suffering from fatty liver disease with genetic profiles seen in the general population. We found that particular sequences in 4 different areas of the human genome were seen at different frequencies in the fatty liver disease cases. These sequences may help predict an individual's risk of developing advanced disease. Some genes where these sequences are located may also be good targets for future drug treatments.
Lay Summary: The prevalence of non-alcoholic fatty liver disease (NAFLD) in pregnancy has almost tripled over the past 10 years. Having NAFLD during pregnancy increases risks for both the mother and the baby, including hypertensive complications of pregnancy, bleeding after delivery, and preterm birth. Thus, pre-conception counseling is warranted with consideration of high-risk obstetric management among women with NAFLD in pregnancy.
Lay Summary: We combined all available studies to estimate how many people with hepatitis B also have hepatitis D, a viral infection that only affects people with hepatitis B. About 1 in 22 people with hepatitis B also have hepatitis D, increasing to 1 in 6 when considering people with liver disease. Hepatitis D may cause about 1 in 6 of the cases of cirrhosis and 1 in 5 of the cases of liver cancer that occur in people with hepatitis B. Hepatitis D is an important contributor to the global burden of liver disease.
Lay Summary: Hepatitis D virus (HDV) is a defective pathogen requiring hepatitis B virus (HBV) to complete its life cycle. Chronic hepatitis D is the most severe form of chronic viral hepatitis, increasing the risk of cirrhosis, liver decompensation and death compared to HBV monoinfection. However, the association between HDV infection and increased risk of hepatocellular carcinoma is debated. We conducted a systematic review and found that patients with HDV infection had a significantly higher risk of developing hepatocellular carcinoma than those with HBV monoinfection.
Lay Summary: Hepatitis C virus infection can now be cured with medications, even in patients who have advanced scarring of the liver (cirrhosis). In this study, we evaluated whether liver function improves or deteriorates in the long-term, following successful treatment of hepatitis C in patients with cirrhosis. We found that overall liver function was relatively stable with only 29% of patients achieving a clinically meaningful improvement in liver function, and we therefore believe that these patients require ongoing monitoring.
Lay Summary: Interferon-stimulated genes are thought to be important to for antiviral immune responses to HCV. Herein, we analysed C19orf66, an interferon-stimulated gene, which appears to inhibit HCV replication. It prevents the HCV-induced elevation of phosphatidylinositol-4-phosphate and alters the morphology of HCV's replication organelle.
Lay Summary: Recurrence of primary biliary cholangitis after liver transplantation is frequent and can impair graft and patient survival. We performed the largest international study of transplanted patients with primary biliary cholangitis to date. Preventive administration of ursodeoxycholic acid after liver transplantation was associated with reduced risk of disease recurrence, graft loss, liver-related and all-cause mortality. A regimen combining cyclosporine and preventive ursodeoxycholic acid was associated with the best outcomes.
Lay Summary: Data on liver tests in patients with COVID-19 are scarce. We observed a high prevalence of liver test abnormalities and liver injury in 417 patients with COVID-19 admitted to our referral center, and the prevalence increased substantially during hospitalization. The presence of abnormal liver tests and liver injury were associated with the progression to severe pneumonia. The detrimental effects on liver injury were related to certain medications used during hospitalization, which warrants frequent monitoring and evaluation for these patients.
Lay Summary: Frailty, as measured at a single time point, is predictive of death in patients with cirrhosis, but whether changes in frailty over time are associated with death is unknown. In a study of over 1,000 patients with cirrhosis who underwent frailty testing, we demonstrate that worsening frailty is strongly linked with mortality, regardless of baseline frailty and liver disease severity. Notably, patients who experienced improvements in frailty over time had a lower risk of death/delisting. Our data support the longitudinal measurement of frailty in patients with cirrhosis and lay the foundation for interventional work aimed at reversing frailty.
Lay Summary: This article unveils a new mechanism by which chronic hyperammonemia induces cognitive impairment in rats: chronic hyperammonemia per se induces peripheral inflammation, which mediates many of its effects on the brain, including induction of neuroinflammation, which alters neurotransmission, leading to cognitive impairment. It is also shown that reducing peripheral inflammation by treating rats with anti-TNF-α, which does not cross the blood-brain barrier, prevents hyperammonemia-induced neuroinflammation, alterations in neurotransmission and cognitive impairment.
Lay Summary: This prospective study focuses on the risk of developing de novo or recurrent hepatocellular carcinoma (HCC) after direct-acting antiviral (DAA) treatment in patients with hepatitis C-related cirrhosis. We found that DAA treatment was associated with an early high HCC incidence in patients with undefined or non-malignant nodules, as well as in those with a history of complete response to HCC treatment. Whether this is related to the presence of clinically undetectable nests of cancer cells or to precancerous lesions that may progress to overt HCC upon DAA treatment remains unanswered. No evidence of increased clinical aggressiveness was reported in de novo or recurrent HCC.
Lay Summary: It is not currently known how maternal obesity affects the incidence of liver cancer in offspring. In this study, we identified a microRNA (miR-27a-3p) that was upregulated in obese mothers and could be passed on to their offspring. This microRNA enhanced the risk of liver cancer in offspring by regulating 2 genes (Acsl1 and Aldh2). This mechanism could be a future therapeutic target.
Lay Summary: Autophagy is a regulated process that maintains cellular homeostasis. Impaired autophagy contributes to cell injury and death, thus playing a critical role in the pathogenesis of a number of diseases, including non-alcohol-associated fatty liver and steatohepatitis. Herein, we show that Mlkl-dependent, but Rip3-independent, signaling contributed to diet-induced liver injury and inflammatory responses by inhibiting autophagy. These data identify a novel co-regulatory mechanism between necroptotic and autophagic signaling pathways in non-alcoholic fatty liver disease.
Lay Summary: Paneth cells are present in the lining of the small intestine. They prevent the passage of bacteria from the intestine into the blood circulation by secreting substances to fight bacteria. In this paper, we discovered that these substances not only act against bacteria, but also increase the quantity of blood vessels in the intestine and blood pressure in the portal vein. This is important, because high blood pressure in the portal vein may result in several complications which could be targeted with novel approaches.
Lay Summary: Immune-mediated liver injury commonly occurs during viral infections of the liver. Mucosal-associated invariant T (MAIT) cells are the most abundant innate-like T cells in the human liver. Herein, we have identified a mechanism by which MAIT cells circumvent conventional T cell receptor interactions to exert cytotoxicity. We show that this innate-like cytotoxicity is increased during acute hepatitis A virus infection and correlates with the degree of hepatocyte injury.