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Nonalcoholic fatty liver disease (NAFLD) results in the accumulation of fat in the liver and can progress as an inflammatory disorder with considerable vascular endothelial dysfunction known as nonalcoholic steatohepatitis (NASH). Inflammatory signals can trigger the expression of vascular cell adhesion molecule 1 (VCAM-1) on endothelial cells. VCAM-1 is a surface protein that induces adherence and extravasation of monocytes to blood vessels. In this issue of the JCI, Furuta et al. report on their sequencing of RNA transcripts from the livers of mice fed a NASH-inducing diet. VCAM-1 was upregulated in the whole liver as well as liver sinusoidal endothelial cells (LSECs). When the researchers incubated LSECs with palmitate, a toxic lipid, VCAM-1 was upregulated. Notably, inhibiting VCAM-1 in the NASH model reduced VCAM-1 expression, lessened infiltrating macrophages, and mitigated fibrosis. This study connects steatosis to endothelial dysfunction and inflammation and suggests that targeting VCAM-1 may address fibrosis in patients with NASH., Inflammation underlies nonalcoholic steatohepatitis Nonalcoholic fatty liver disease (NAFLD) is a systemic disease that results from multiorgan metabolic dys regulation, tissue inflammation, and organ dysfunction. It is a chronic condition [...]

This article provides an overview of the role of lipid droplets (LDs) in metabolic-associated fatty liver disease (MASLD), alcohol-associated liver disease (ALD), and hepatitis C. LDs are involved in the storage of lipids and other compounds in cells. The article discusses the biogenesis of LDs, their impact on disease progression, and the role of LD proteins. It highlights the deleterious effects of LD accumulation in the liver and its association with the development of other metabolic diseases. The article also explores how alcohol impairs hepatic lipid metabolism and LD biology in ALD, as well as the interaction between the HCV virus and LDs in hepatitis C. The text emphasizes the importance of understanding LD biology for the development of diagnostic and therapeutic approaches for liver diseases. [Extracted from the article]

Background and aims: There is significant overlap between non-alcoholic fatty liver disease (NAFLD) and alcohol-associated liver disease (ALD) with regards to risk factors and disease progression. However, the mechanism by which fatty liver disease arises from concomitant obesity and overconsumption of alcohol (syndrome of metabolic and alcohol-associated fatty liver disease; SMAFLD), is not fully understood. Methods: Male C57BL6/J mice were fed chow diet (Chow) or high-fructose, high-fat, high-cholesterol diet (FFC) for 4 weeks, then administered either saline or ethanol (EtOH, 5% in drinking water) for another 12 weeks. The EtOH treatment also consisted of a weekly 2.5 g EtOH/kg body weight gavage. Markers for lipid regulation, oxidative stress, inflammation, and fibrosis were measured by RT-qPCR, RNA-seq, Western blot, and metabolomics. Results: Combined FFC-EtOH induced more body weight gain, glucose intolerance, steatosis, and hepatomegaly compared to Chow, EtOH, or FFC. Glucose intolerance by FFC-EtOH was associated with decreased hepatic protein kinase B (AKT) protein expression and increased gluconeogenic gene expression. FFC-EtOH increased hepatic triglyceride and ceramide levels, plasma leptin levels, hepatic Perilipin 2 protein expression, and decreased lipolytic gene expression. FFC and FFC-EtOH also increased AMP-activated protein kinase (AMPK) activation. Finally, FFC-EtOH enriched the hepatic transcriptome for genes involved in immune response and lipid metabolism. Conclusions: In our model of early SMAFLD, we observed that the combination of an obesogenic diet and alcohol caused more weight gain, promoted glucose intolerance, and contributed to steatosis by dysregulating leptin/AMPK signaling. Our model demonstrates that the combination of an obesogenic diet with a chronic-binge pattern alcohol intake is worse than either insult alone. [ABSTRACT FROM AUTHOR]

The article focuses on how metabolic dysfunction-associated steatohepatitis (MASLD), previously known as NAFLD, elevates the risk of various cardiometabolic, oncologic, and hepatic complications.

My experience I am a Black woman hepatologist and hepatic lipid droplet biology physician-scientist. I have a nontraditional path as a researcher, having begun my career as a general internal [...]

Background: COVID-19 is associated with higher morbidity and mortality in patients with chronic liver diseases (CLDs). However, our understanding of the long-term outcomes of COVID-19 in patients with CLD is limited. Methods: We conducted a multicenter, observational cohort study of adult patients with CLD who were diagnosed with COVID-19 before May 30, 2020, to determine long-term clinical outcomes. We used a control group of patients with CLD confirmed negative for COVID-19. Results: We followed 666 patients with CLD (median age 58 years, 52.8% male) for a median of 384 (interquartile range: 31-462) days. The long-term mortality was 8.1%; with 3.6% experiencing delayed COVID-19-related mortality. Compared to a propensity-matched control group of patients with CLD without COVID-19 (n= 1332), patients with CLD with COVID-19 had worse long-term survival [p< 0.001; hazards ratio (HR): 1.69; 95% CI: 1.19-2.41] and higher rate of hospitalization (p< 0.001, HR: 2.00, 1.62-2.48) over a 1-year follow-up period. Overall, 29.9% of patients reported symptoms of long-COVID-19. On multivariable analysis, female sex (p= 0.05, HR: 2.45, 1.01-2.11), Hispanic ethnicity (p =0.003, HR: 1.94, 1.26-2.99), and severe COVID-19 requiring mechanical ventilation (p =0.028, HR: 1.74, 1.06-2.86) predicted long-COVID-19. In survivors, liver-related laboratory parameters showed significant improvement after COVID-19 resolution. COVID-19 vaccine status was available for 72% (n =470) of patients with CLD and history of COVID-19, of whom, 70% (n =326) had received the COVID-19 vaccine. Conclusions: Our large, longitudinal, multicenter study demonstrates a high burden of long-term mortality and morbidity in patients with CLD and COVID-19. Symptoms consistent with long-COVID-19 were present in 30% of patients with CLD. These results illustrate the prolonged implications of COVID-19 both for recovering patients and for health care systems. [ABSTRACT FROM AUTHOR]

Lipid droplets (LDs) are complex and metabolically active organelles. They are composed of a neutral lipid core surrounded by a monolayer of phospholipids and proteins. LD accumulation in hepatocytes is the distinctive characteristic of non-alcoholic fatty liver disease (NAFLD), which is a chronic, heterogeneous liver condition that can progress to liver fibrosis and hepatocellular carcinoma. Though recent research has improved our understanding of the mechanisms linking LD accumulation to NAFLD progression, numerous aspects of LD biology are either poorly understood or unknown. In this review, we provide a description of several key mechanisms that contribute to LD accumulation in hepatocytes, favouring NAFLD progression. First, we highlight the importance of LD architecture and describe how the dysregulation of LD biogenesis leads to endoplasmic reticulum stress and inflammation. This is followed by an analysis of the causal nexus that exists between LD proteome composition and LD degradation. Finally, we describe how the increase in size of LDs causes activation of hepatic stellate cells, leading to liver fibrosis and hepatocellular carcinoma. We conclude that acquiring a more sophisticated understanding of LD biology will provide crucial insights into the heterogeneity of NAFLD and assist in the development of therapeutic approaches for this liver disease. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic halted research operations at academic medical centers. This shutdown has adversely affected research infrastructure, the current research workforce, and the research pipeline. We discuss the impact of the pandemic on overall research operations, examine its disproportionate effect on underrepresented minority researchers, and provide concrete strategies to reverse these losses. [ABSTRACT FROM AUTHOR]

Background & aims: Given ongoing challenges in non-invasive non-alcoholic liver disease (NAFLD) diagnosis, we sought to validate an ALT-based NAFLD phenotype using measures readily available in electronic health records (EHRs) and population-based studies by leveraging the clinical and genetic data in the Million Veteran Program (MVP), a multi-ethnic mega-biobank of US Veterans. Methods: MVP participants with alanine aminotransferases (ALT) >40 units/L for men and >30 units/L for women without other causes of liver disease were compared to controls with normal ALT. Genetic variants spanning eight NAFLD risk or ALT-associated loci (LYPLAL1, GCKR, HSD17B13, TRIB1, PPP1R3B, ERLIN1, TM6SF2, PNPLA3) were tested for NAFLD associations with sensitivity analyses adjusting for metabolic risk factors and alcohol consumption. A manual EHR review assessed performance characteristics of the NAFLD phenotype with imaging and biopsy data as gold standards. Genetic associations with advanced fibrosis were explored using FIB4, NAFLD Fibrosis Score and platelet counts. Results: Among 322,259 MVP participants, 19% met non-invasive criteria for NAFLD. Trans-ethnic meta-analysis replicated associations with previously reported genetic variants in all but LYPLAL1 and GCKR loci (P<6x10-3), without attenuation when adjusted for metabolic risk factors and alcohol consumption. At the previously reported LYPLAL1 locus, the established genetic variant did not appear to be associated with NAFLD, however the regional association plot showed a significant association with NAFLD 279kb downstream. In the EHR validation, the ALT-based NAFLD phenotype yielded a positive predictive value 0.89 and 0.84 for liver biopsy and abdominal imaging, respectively (inter-rater reliability (Cohen's kappa = 0.98)). HSD17B13 and PNPLA3 loci were associated with advanced fibrosis. Conclusions: We validate a simple, non-invasive ALT-based NAFLD phenotype using EHR data by leveraging previously established NAFLD risk-associated genetic polymorphisms. [ABSTRACT FROM AUTHOR]

Human but not mouse islets transplanted into immunodeficient NSG mice effectively accumulate lipid droplets (LDs). Because chronic lipid exposure is associated with islet β-cell dysfunction, we investigated LD accumulation in the intact human and mouse pancreas over a range of ages and states of diabetes. Very few LDs were found in normal human juvenile pancreatic acinar and islet cells, with numbers subsequently increasing throughout adulthood. While accumulation appeared evenly distributed in postjuvenile acinar and islet cells in donors without diabetes, LDs were enriched in islet α- and β-cells from donors with type 2 diabetes (T2D). LDs were also found in the islet β-like cells produced from human embryonic cell-derived β-cell clusters. In contrast, LD accumulation was nearly undetectable in the adult rodent pancreas, even in hyperglycemic and hyperlipidemic models or 1.5-year-old mice. Taken together, there appear to be significant differences in pancreas islet cell lipid handling between species, and the human juvenile and adult cell populations. Moreover, our results suggest that LD enrichment could be impactful to T2D islet cell function. [ABSTRACT FROM AUTHOR]