Opioid-like compound exerts anti-fibrotic activity via decreased hepatic stellate cell activation and inflammation

Abnormal metabolism in hepatic stellate cells: Pandora's box of MAFLD related hepatocellular carcinoma

Metabolic associated fatty liver disease (MAFLD) is a significant risk factor for the development of hepatocellular carcinoma (HCC). Hepatic stellate cells (HSCs), as key mediators in liver injury response, are believed to play a crucial role in the repair process of liver injury. However, in MAFLD patients, the normal metabolic and immunoregulatory mechanisms of HSCs become disrupted, leading to disturbances in the local microenvironment. Abnormally activated HSCs are heavily involved in the initiation and progression of HCC. The metabolic disorders and abnormal activation of HSCs not only initiate liver fibrosis but also contribute to carcinogenesis. In this review, we provide an overview of recent research progress on the relationship between the abnormal metabolism of HSCs and the local immune system in the liver, elucidating the mechanisms of immune imbalance caused by abnormally activated HSCs in MAFLD patients. Based on this understanding, we discuss the potential and challenges of metabolic-based and immunology-based mechanisms in the treatment of MAFLD-related HCC, with a specific focus on the role of HSCs in HCC progression and their potential as targets for anti-cancer therapy. This review aims to enhance researchers' understanding of the importance of HSCs in maintaining normal liver function and highlights the significance of HSCs in the progression of MAFLD-related HCC.

Strategies Targeting the Innate Immune Response for the Treatment of Hepatitis C Virus-Associated Liver Fibrosis

Direct-acting antivirals eliminate hepatitis C virus (HCV) in more than 95% of treated individuals and may abolish liver injury, arrest fibrogenesis, and reverse fibrosis and cirrhosis. However, liver regeneration is usually a slow process that is less effective in the late stages of fibrosis. What is more, fibrogenesis may prevail in patients with advanced cirrhosis, where it can progress to liver failure and hepatocellular carcinoma. Therefore, the development of antifibrotic drugs that halt and reverse fibrosis progression is urgently needed. Fibrosis occurs due to the repair process of damaged hepatic tissue, which eventually leads to scarring. The innate immune response against HCV is essential in the initiation and progression of liver fibrosis. HCV-infected hepatocytes and liver macrophages secrete proinflammatory cytokines and chemokines that promote the activation and differentiation of hepatic stellate cells (HSCs) to myofibroblasts that produce extracellular matrix (ECM) components. Prolonged ECM production by myofibroblasts due to chronic inflammation is essential to the development of fibrosis. While no antifibrotic therapy is approved to date, several drugs are being tested in phase 2 and phase 3 trials with promising results. This review discusses current state-of-the-art knowledge on treatments targeting the innate immune system to revert chronic hepatitis C-associated liver fibrosis. Agents that cause liver damage may vary (alcohol, virus infection, etc.), but fibrosis progression shows common patterns among them, including chronic inflammation and immune dysregulation, hepatocyte injury, HSC activation, and excessive ECM deposition. Therefore, mechanisms underlying these processes are promising targets for general antifibrotic therapies.

Hepatoprotective Effects of Morchella esculenta against Alcohol-Induced Acute Liver Injury in the C57BL/6 Mouse Related to Nrf-2 and NF-κB Signaling

This study investigated the hepatoprotective effects of Morchella esculenta fruit body (ME) and the underlying mechanisms in mice with alcohol-induced acute liver injury. Systematic analysis revealed that ME contained 21 types of fatty acid, 17 types of amino acid, and 12 types of mineral. Subsequently, a mouse model of acute alcohol-induced liver injury was established by oral administration of alcohol for 14 days. Fourteen-day administration of ME prevented alcohol-induced increases in alanine aminotransferase and aspartate aminotransferase levels and reduced the activity of acetaldehyde dehydrogenase in blood serum and liver tissue. ME appears to regulate lipid metabolism by suppressing triglycerides, total cholesterol, and high-density lipoprotein in the liver. ME inhibited the production of inflammatory factors including chitinase-3-like protein 1 (YKL 40), interleukin-7 (IL-7), plasminogen activator inhibitor type 1 (PAI-1), and retinol-binding protein 4 (RBP4) in blood serum and/or liver tissue. ME treatment relieved the alcohol-induced imbalance in prooxidative and antioxidative signaling via nuclear factor-erythroid 2-related factor 2 (Nrf-2), as indicated by upregulation of superoxide dismutase-1, superoxide dismutase-2, catalase, heme oxygenase-1, and heme oxygenase-2 expression and downregulation of kelch-like ECH-associated protein 1 (Keap-1) in the liver. Moreover, ME reduced the levels of phosphorylated nuclear factor kappa-B kinase α/β, inhibitor of nuclear factor kappa-B α and nuclear factor kappa-B p65 (NF-κB p65) in the liver. The hepatoprotective effects of ME against alcohol-induced acute liver injury were thus confirmed. The mechanism of action may be related to modulation of antioxidative and anti-inflammatory signaling pathways, partially via regulation of Nrf-2 and NF-κB signaling.

Metabolic derivatives of alcohol and the molecular culprits of fibro-hepatocarcinogenesis: Allies or enemies?

Chronic intake of alcohol undoubtedly overwhelms the structural and functional capacity of the liver by initiating complex pathological events characterized by steatosis, steatohepatitis, hepatic fibrosis and cirrhosis. Subsequently, these initial pathological events are sustained and ushered into a more complex and progressive liver disease, increasing the risk of fibro-hepatocarcinogenesis. These coordinated pathological events mainly result from buildup of toxic metabolic derivatives of alcohol including but not limited to acetaldehyde (AA), malondialdehyde (MDA), CYP2E1-generated reactive oxygen species, alcohol-induced gut-derived lipopolysaccharide, AA/MDA protein and DNA adducts. The metabolic derivatives of alcohol together with other comorbidity factors, including hepatitis B and C viral infections, dysregulated iron metabolism, abuse of antibiotics, schistosomiasis, toxic drug metabolites, autoimmune disease and other non-specific factors, have been shown to underlie liver diseases. In view of the multiple etiology of liver diseases, attempts to delineate the mechanism by which each etiological factor causes liver disease has always proved cumbersome if not impossible. In the case of alcoholic liver disease (ALD), it is even more cumbersome and complicated as a result of the many toxic metabolic derivatives of alcohol with their varying liver-specific toxicities. In spite of all these hurdles, researchers and experts in hepatology have strived to expand knowledge and scientific discourse, particularly on ALD and its associated complications through the medium of scientific research, reviews and commentaries. Nonetheless, the molecular mechanisms underpinning ALD, particularly those underlying toxic effects of metabolic derivatives of alcohol on parenchymal and non-parenchymal hepatic cells leading to increased risk of alcohol-induced fibro-hepatocarcinogenesis, are still incompletely elucidated. In this review, we examined published scientific findings on how alcohol and its metabolic derivatives mount cellular attack on each hepatic cell and the underlying molecular mechanisms leading to disruption of core hepatic homeostatic functions which probably set the stage for the initiation and progression of ALD to fibro-hepatocarcinogenesis. We also brought to sharp focus, the complex and integrative role of transforming growth factor beta/small mothers against decapentaplegic/plasminogen activator inhibitor-1 and the mitogen activated protein kinase signaling nexus as well as their cross-signaling with toll-like receptor-mediated gut-dependent signaling pathways implicated in ALD and fibro-hepatocarcinogenesis. Looking into the future, it is hoped that these deliberations may stimulate new research directions on this topic and shape not only therapeutic approaches but also models for studying ALD and fibro-hepatocarcinogenesis.

Capsaicin modulates proliferation, migration, and activation of hepatic stellate cells

Capsaicin, the active component of chili pepper, has been reported to have antiproliferative and anti-inflammatory effects on a variety of cell lines. In the current study, we aimed to investigate the effects of capsaicin during HSC activation and maintenance. Activated and freshly isolated HSCs were treated with capsaicin. Proliferation was measured by incorporation of EdU. Cell cycle arrest and apoptosis were investigated using flow cytometry. The migratory response to chemotactic stimuli was evaluated by a modified Boyden chamber assay. Activation markers and inflammatory cytokines were determined by qPCR, immunocytochemistry, and flow cytometry. Our results show that capsaicin reduces HSC proliferation, migration, and expression of profibrogenic markers of activated and primary mouse HSCs. In conclusion, the present study shows that capsaicin modulates proliferation, migration, and activation of HSC in vitro.

Naltrexone prevents delayed encephalopathy in rats poisoned with the sarin analogue diisopropylflurophosphate

BACKGROUND

Acute poisoning with organophosphate compounds can cause chronic neuropsychological disabilities not prevented by standard antidotes of atropine and pralidoxime. We determine the efficacy of naltrexone in preventing delayed encephalopathy after poisoning with the sarin analogue diisofluorophosphate (DFP) in rats.

METHODS

A randomized controlled experiment was conducted. Rats were randomly assigned to receive a single intraperitoneal (IP) injection of 5 mg/kg DFP (n = 12) or vehicle control (isopropyl alcohol, n = 5). Rats were observed for cholinesterase toxicity and treated with IP atropine (2 mg/kg) and pralidoxime (25 mg/kg) as needed. After resolution of acute toxicity, rats injected with DFP were again randomized to receive daily injections of naltrexone (5 mg/kg per day) or saline (vehicle control). Control animals also received daily injections of saline. For 4 weeks after acute poisoning, rats underwent neurologic testing with the Morris Water Maze for assessment of spatial learning and reference memory. Comparisons on each test day were made across groups using analysis of variance followed by Fisher's least significant difference. Comparisons of changes in performance between first and last test day within each group were made using a paired t test. Significance was determined at P < .05.

RESULTS

All rats receiving DFP developed toxicity requiring rescue. Spatial learning was significantly worse in the DFP-only group compared with the naltrexone-treated and control groups at day 10 (P = .0078), day 13 (P = .01), day 24 (P = .034), and day 31 (P = .03). No significant differences in reference memory were detected at any time point.

CONCLUSION

Naltrexone protected against impairment of spatial learning from acute poisoning with DFP in rats.

Endogenous opiates and behavior: 2011

This paper is the thirty-fourth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2011 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration (Section 16); and immunological responses (Section 17).