What are the mechanisms of regeneration inhibition in alcoholic hepatitis?

Insights into the Role of Granulocyte Colony-Stimulating Factor in Severe Alcoholic Hepatitis

Alcohol use disorder is the predominant cause of chronic liver disease globally. The standard of care for the treatment of alcoholic hepatitis, corticosteroids, has been shown to provide a therapeutic response in ∼60% of carefully selected patients with a short-term survival benefit. The patients who do not respond to steroids, or are ineligible due to infections or very severe disease, have little options other than liver transplantation. There is, thus, a large unmet need for new therapeutic strategies for this large and sick group of patients. Granulocyte colony stimulating factor (G-CSF) has been shown to favorably modulate the intrahepatic immune milieu and stimulate the regenerative potential of the liver. Initial studies have shown encouraging results with G-CSF in patients with severe alcoholic hepatitis. It has also been found to help steroid nonresponsive patients. There is, however, a need for careful selection of patients, regular dose monitoring and close observation for adverse events of G-CSF. In this review, we analyze the basis of the potential benefits, clinical studies, cautions and challenges in the use of G-CSF in alcoholic hepatitis.

Suppressed hepatocyte proliferation via a ROS-HNE-P21 pathway is associated with nicotine- and cotinine-enhanced alcoholic fatty liver in mice

CYP2A5 is a major enzyme responsible for nicotine and cotinine metabolism in mice. Nicotine and cotinine enhance alcoholic fatty liver in wild type (WT) mice but not in CYP2A5 knockout (KO) mice, and reactive oxygen species (ROS) generated during the CYP2A5-mediated metabolism contributes to the enhancing effect. In combination with ethanol, nicotine and cotinine increased lipid peroxidation end product 4-hydroxynonenal (HNE) in WT mice but not in KO mice. In ethanol-fed KO mice, only 5 and 10 genes were regulated by nicotine and cotinine, respectively. However, in ethanol-fed WT mice, 59 and 104 genes were regulated by nicotine and cotinine, respectively, and 7 genes were up-regulated by both nicotine and cotinine. Plin 2 and Cdkn1a are among the 7 genes. Plin2 encodes adipose differentiation-related protein (ADRP), a lipid droplet-associated protein, which was confirmed to be increased by nicotine and cotinine in WT mice but not in KO mice. Cdkn1a encodes P21 and elevated P21 in nuclei was also confirmed. HNE can increase P21 and P21 inhibit cell proliferation. Consistently, hepatocyte proliferation markers proliferating cell nuclear antigen (PCNA) and Ki67 were decreased in WT mice but not in KO mice by nicotine/ethanol and cotinine/ethanol, respectively. These results suggest that inhibition of liver proliferation via a ROS-HNE-P21 pathway is involved in nicotine- and cotinine-enhanced alcoholic fatty liver.

Alcoholic liver disease: A current molecular and clinical perspective

Heavy alcohol use is the cause of alcoholic liver disease (ALD). The ALD spectrum ranges from alcoholic steatosis to steatohepatitis, fibrosis, and cirrhosis. In Western countries, approximately 50% of cirrhosis-related deaths are due to alcohol use. While alcoholic cirrhosis is no longer considered a completely irreversible condition, no effective anti-fibrotic therapies are currently available. Another significant clinical aspect of ALD is alcoholic hepatitis (AH). AH is an acute inflammatory condition that is often comorbid with cirrhosis, and severe AH has a high mortality rate. Therapeutic options for ALD are limited. The established treatment for AH is corticosteroids, which improve short-term survival but do not affect long-term survival. Liver transplantation is a curative treatment option for alcoholic cirrhosis and AH, but patients must abstain from alcohol use for 6 months to qualify. Additional effective therapies are needed. The molecular mechanisms underlying ALD are complex and have not been fully elucidated. Various molecules, signaling pathways, and crosstalk between multiple hepatic and extrahepatic cells contribute to ALD progression. This review highlights established and emerging concepts in ALD clinicopathology, their underlying molecular mechanisms, and current and future ALD treatment options.

Over expression of proteins that alter the intracellular signaling pathways in the cytoplasm of the liver cells forming Mallory-Denk bodies

In this study, liver biopsy sections fixed in formalin and embedded in paraffin (FFPE) from patients with alcoholic hepatitis (AH) were used. The results showed that the expression of the SYK protein was up regulated by RNA-seq and real time PCR analyses in the alcoholic hepatitis patients compared to controls. The results were supported by using the IHC fluorescent antibody staining intensity morphometric quantitation. Morphometric quantification of fluorescent intensity measurement showed a two fold increase in SYK protein in the cytoplasm of the cells forming MDBs compared to surrounding normal hepatocytes. The expression of AKT1 was also analyzed. AKT1 is a serine/threonine-specific protein kinase that plays a key role in multiple cellular processes such as glucose metabolism, apoptosis, cell proliferation, transcription and cell migration. The AKT protein was also increased in hepatocyte balloon cells forming MDBs. This observation demonstrates the role of SYK and its subsequent effect on the internal signaling pathways such as PI3K/AKT as well as p70S6K, as a potential multifunctional target in protein quality control mechanisms of hepatocytes when ER stress is activated.