Nanoformulated SOD1 ameliorates the combined NASH and alcohol-associated liver disease partly via regulating CYP2E1 expression in adipose tissue and liver

Decreased antioxidant-related superoxide dismutase 1 expression in peripheral immune cells indicates early ethanol exposure

Alcohol consumption increases oxidative stress and imbalances in the antioxidant system, even with ethanol (EtOH) exposure at a young age. This study assessed changes in the antioxidant system following young EtOH exposure in peripheral immunity and measured sensitive indicators of heavy alcohol consumption. We used peripheral blood mononuclear cells (PBMCs) from 197 male university students without smoking habits to examine changes in antioxidant-related gene expression in vitro and in PBMCs. In vitro, the antioxidant system was impaired by EtOH. Next, we examined the expression of 84 antioxidant-related genes in the PBMCs of 162 young adults, among which the superoxide dismutase (SOD) 1 expression was most negatively correlated with alcohol consumption degree. The plasma SOD1 level had the highest area under the curve value (0.806) for heavy alcohol consumption. Our data demonstrated that a decreased SOD1 level is a sensitive indicator of an impaired antioxidant system and heavy alcohol consumption with early EtOH exposure.

A model of alcoholic liver disease based on different hepatotoxics leading to liver cancer

The worst-case scenario related to alcoholic liver disease (ALD) arises after a long period of exposure to the harmful effect of alcohol consumption along with other hepatotoxics. ALD encompasses a broad spectrum of liver-associated disorders, such as steatosis, steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). Based on the chronic administration of different hepatotoxics, including ethanol, sucrose, lipopolysaccharide, and low doses of diethylnitrosamine over a short period, here we aimed to develop a multiple hepatotoxic (MHT)-ALD model in the mouse that recapitulates the human ALD-associated disorders. We demonstrated that the MHT-ALD model induces ADH1A and NXN, an ethanol metabolizer and a redox-sensor enzyme, respectively; promotes steatosis associated with the induction of the lipid droplet forming FSP27, inflammation identified by the infiltration of hepatic neutrophils-positive to LY-6G marker, and the increase of MYD88 level, a protein involved in inflammatory response; and stimulates the early appearance of cellular senescence identified by the senescence markers SA-β-gal activity and p-H2A.XSer139. It also induces fibrosis associated with increased desmin, a marker of hepatic stellate cells whose activation leads to the deposition of collagen fibers, accompanied by cell death and compensatory proliferation revealed by increased CASP3-mediated apoptosis, and KI67- and PCNA-proliferation markers, respectively. It also induces histopathological traits of malignancy and the level of the HCC marker, GSTP1. In conclusion, we provide a useful model for exploring the chronological ALD-associated alterations and stages, and addressing therapeutic approaches.

Obesity Induces DNA Damage in Mammary Epithelial Cells Exacerbated by Acrylamide Treatment through CYP2E1-Mediated Oxidative Stress

Obesity and environmental toxins are risk factors for breast cancer; however, there is limited knowledge on how these risk factors interact to promote breast cancer. Acrylamide, a probable carcinogen and obesogen, is a by-product in foods prevalent in the obesity-inducing Western diet. Acrylamide is metabolized by cytochrome P450 2E1 (CYP2E1) to the genotoxic epoxide, glycidamide, and is associated with an increased risk for breast cancer. To investigate how acrylamide and obesity interact to increase breast cancer risk, female mice were fed a low-fat (LFD) or high-fat diet (HFD) and control water or water supplemented with acrylamide at levels similar to the average daily exposure in humans. While HFD significantly enhanced weight gain in mice, the addition of acrylamide did not significantly alter body weights compared to respective controls. Mammary epithelial cells from obese, acrylamide-treated mice had increased DNA strand breaks and oxidative DNA damage compared to all other groups. In vitro, glycidamide-treated COMMA-D cells showed significantly increased DNA strand breaks, while acrylamide-treated cells demonstrated significantly higher levels of intracellular reactive oxygen species. The knockdown of CYP2E1 rescued the acrylamide-induced oxidative stress. These studies suggest that long-term acrylamide exposure through foods common in the Western diet may enhance DNA damage and the CYP2E1-induced generation of oxidative stress in mammary epithelial cells, potentially enhancing obesity-induced breast cancer risk.

Adipose tissue homeostasis orchestrates the oxidative, energetic, metabolic and endocrine disruption induced by binge drinking in adolescent rats

Binge drinking (BD) is the most common alcohol consumption model for adolescents, and has recently been related to the generation of high oxidation and insulin resistance (IR). White adipose tissue (WAT) is a target organ for insulin action that regulates whole-body metabolism by secreting adipokines. The present study aimed to analyse the oxidative, inflammatory, energetic and endocrine profile in the WAT of BD-exposed adolescent rats, to obtain an integrative view of insulin secretion and WAT in IR progression. Two groups of male adolescent rats were used: control (n = 8) and BD (n = 8). An intermittent i.p. BD model (20% v/v) was used during 3 consecutive weeks. BD exposure led to a pancreatic oxidative imbalance, which was joint to high insulin secretion by augmenting deacetylase sirtuin-1 (SIRT-1) pancreatic expression and serum adipsin levels. However, BD rats had hyperglycaemia and high homeostasis model assessment of insulin resistance value (HOMA-IR). BD exposure in WAT increased lipid oxidation, as well as decreased insulin receptor substrate 1 (IRS-1) and AKT expression, sterol regulatory element-binding protein 1 (SREBP1), forkhead box O3A (FOXO3a) and peroxisome proliferator-activated receptor γ (PPARγ), and adipocyte size. BD also affected the expression of proteins related to energy balance, such as SIRT-1 and AMP activated protein kinase (AMPK), affecting the adipokine secretion profile (increasing resistin/adiponectin ratio). BD altered the entire serum lipid profile, increasing the concentration of free fatty acids. In conclusion, BD led to an oxidative imbalance and IR process in WAT, which modified the energy balance in this tissue, decreasing the WAT lipogenic/lipolytic ratio, affecting adipokine secretion and the systemic lipid profile, and contributing to the progression of IR. Therefore, WAT is key in the generation of metabolic and endocrine disruption after BD exposure during adolescence in rats. KEY POINTS: Adolescent rat binge drinking (BD) exposure leads to hepatic and systemic oxidative stress (OS) via reactive oxygen species generation, causing hepatic insulin resistance (IR) and altered energy metabolism. In the present study, BD exposure in adolescent rats induces OS in the pancreas, with increased insulin secretion despite hyperglycaemia, indicating a role for IR in white adipose tissue (WAT) homeostasis. In WAT, BD produces IR and an oxidative and energetic imbalance, triggering an intense lipolysis where the serum lipid profile is altered and free fatty acids are increased, consistent with liver lipid accumulation and steatosis. BD exposure heightens inflammation in WAT, elevating pro-inflammatory and reducing anti-inflammatory adipokines, favouring cardiovascular damage. This research provides a comprehensive view of how adolescent BD in rats impacts liver, WAT and pancreas homeostasis, posing a risk for future cardiometabolic complications in adulthood.

Stress mechanism involved in the progression of alcoholic liver disease and the therapeutic efficacy of nanoparticles

Alcoholic liver disease (ALD) poses a significant threat to human health, with excessive alcohol intake disrupting the immunotolerant environment of the liver and initiating a cascade of pathological events. This progressive disease unfolds through fat deposition, proinflammatory cytokine upregulation, activation of hepatic stellate cells, and eventual development of end-stage liver disease, known as hepatocellular carcinoma (HCC). ALD is intricately intertwined with stress mechanisms such as oxidative stress mediated by reactive oxygen species, endoplasmic reticulum stress, and alcohol-induced gut dysbiosis, culminating in increased inflammation. While the initial stages of ALD can be reversible with diligent care and abstinence, further progression necessitates alternative treatment approaches. Herbal medicines have shown promise, albeit limited by their poor water solubility and subsequent lack of extensive exploration. Consequently, researchers have embarked on a quest to overcome these challenges by delving into the potential of nanoparticle-mediated therapy. Nanoparticle-based treatments are being explored for liver diseases that share similar mechanisms with alcoholic liver disease. It underscores the potential of these innovative approaches to counteract the complex pathogenesis of ALD, providing new avenues for therapeutic intervention. Nevertheless, further investigations are imperative to fully unravel the therapeutic potential and unlock the promise of nanoparticle-mediated therapy specifically tailored for ALD treatment.

Stress mechanism involved in the progression of alcoholic liver disease and the therapeutic efficacy of nanoparticles

Alcoholic liver disease (ALD) poses a significant threat to human health, with excessive alcohol intake disrupting the immunotolerant environment of the liver and initiating a cascade of pathological events. This progressive disease unfolds through fat deposition, proinflammatory cytokine upregulation, activation of hepatic stellate cells, and eventual development of end-stage liver disease, known as hepatocellular carcinoma (HCC). ALD is intricately intertwined with stress mechanisms such as oxidative stress mediated by reactive oxygen species, endoplasmic reticulum stress, and alcohol-induced gut dysbiosis, culminating in increased inflammation. While the initial stages of ALD can be reversible with diligent care and abstinence, further progression necessitates alternative treatment approaches. Herbal medicines have shown promise, albeit limited by their poor water solubility and subsequent lack of extensive exploration. Consequently, researchers have embarked on a quest to overcome these challenges by delving into the potential of nanoparticle-mediated therapy. Nanoparticle-based treatments are being explored for liver diseases that share similar mechanisms with alcoholic liver disease. It underscores the potential of these innovative approaches to counteract the complex pathogenesis of ALD, providing new avenues for therapeutic intervention. Nevertheless, further investigations are imperative to fully unravel the therapeutic potential and unlock the promise of nanoparticle-mediated therapy specifically tailored for ALD treatment.

iTRAQ-based quantitative proteomics analysis of the effect of ACT001 on non-alcoholic steatohepatitis in mice

ACT001 is a novel sesquiterpene lactone derivative that has been shown to have significant antitumor and anti-inflammatory effects. However, the effect of ACT001 on nonalcoholic steatohepatitis (NASH) is unknown. Methionine and choline deficient (MCD) diet induced NASH model in C57BL/6J mice. Steatosis, inflammation and fibrosis-related indices of serum and liver tissues were detected by fully automated biochemical analyzer, enzyme-linked immunosorbent assay (ELISA) kit, flow cytometry, hematoxylin and eosin (H&E), Masson and immunohistochemical staining. The results showed that ACT001 reduced serum lipid and inflammatory factor levels, attenuated hepatic steatosis, inflammation and fibrosis, and inhibited hepatic oxidative stress and activation of NOD-like receptor protein 3 (NLRP3) inflammatory vesicles in NASH mice. In addition, 381 differentially expressed proteins (DEPs), including 162 up-regulated and 219 down-regulated proteins, were identified in the MCD group and ACT001 high-dose group using isotope labeling relative and absolute quantification (iTRAQ) technique analysis. Among these DEPs, five proteins associated with NAFLD were selected for real-time fluorescence quantitative PCR (RT-qPCR) validation, and the results were consistent with proteomics. In conclusion, ACT001 has a therapeutic effect on NASH, and the results of proteomic analysis will provide new ideas for the mechanism study of ACT001 for NASH treatment.

Experimental models of fatty liver diseases: Status and appraisal

Fatty liver diseases, including alcohol-associated liver disease (ALD) and nonalcoholic fatty liver disease nonalcoholic fatty liver disease (NAFLD), affect a large number of people worldwide and become one of the major causes of end-stage liver disease, such as liver cirrhosis and hepatocellular carcinoma (HCC). Unfortunately, there are currently no approved pharmacological treatments for ALD or NAFLD. This situation highlights the urgent need to explore new intervention targets and discover effective therapeutics for ALD and NAFLD. The lack of properly validated preclinical disease models is a major obstacle to the development of clinical therapies. ALD and NAFLD models have been in the development for decades, but there are still no models that recapitulate the full spectrum of ALD and NAFLD. Throughout this review, we summarize the current in vitro and in vivo models used for research on fatty liver diseases and discuss the advantages and limitations of these models.

Mitochondrial Dysfunction: At the Nexus between Alcohol-Associated Immunometabolic Dysregulation and Tissue Injury

Alcohol misuse, directly or indirectly as a result of its metabolism, negatively impacts most tissues, including four with critical roles in energy metabolism regulation: the liver, pancreas, adipose, and skeletal muscle. Mitochondria have long been studied for their biosynthetic roles, such as ATP synthesis and initiation of apoptosis. However, current research has provided evidence that mitochondria participate in myriad cellular processes, including immune activation, nutrient sensing in pancreatic β-cells, and skeletal muscle stem and progenitor cell differentiation. The literature indicates that alcohol impairs mitochondrial respiratory capacity, promoting reactive oxygen species (ROS) generation and disrupting mitochondrial dynamics, leading to dysfunctional mitochondria accumulation. As discussed in this review, mitochondrial dyshomeostasis emerges at a nexus between alcohol-disrupted cellular energy metabolism and tissue injury. Here, we highlight this link and focus on alcohol-mediated disruption of immunometabolism, which refers to two distinct, yet interrelated processes. Extrinsic immunometabolism involves processes whereby immune cells and their products influence cellular and/or tissue metabolism. Intrinsic immunometabolism describes immune cell fuel utilization and bioenergetics that affect intracellular processes. Alcohol-induced mitochondrial dysregulation negatively impacts immunometabolism in immune cells, contributing to tissue injury. This review will present the current state of literature, describing alcohol-mediated metabolic and immunometabolic dysregulation from a mitochondrial perspective.

Pathogenetic Pathways in Nonalcoholic Fatty Liver Disease: An Incomplete Jigsaw Puzzle

Nonalcoholic fatty liver disease (NAFLD)-a condition of excess fat accumulation in hepatocytes associated with metabolic dysfunction-has surpassed viral hepatitis to become the most prevalent chronic liver disease worldwide. As of now, only modestly effective pharmacological therapies for NAFLD exist. The uncomplete understanding of the pathophysiology underlying the heterogeneous disease spectrum known as NAFLD remains one of the major obstacles to the development of novel therapeutic approaches. This review compiles current knowledge on the principal signaling pathways and pathogenic mechanisms involved in NAFLD, which are analyzed in relation to its main pathological hallmarks (ie, hepatic steatosis, steatohepatitis, and liver fibrosis).

Pathogenesis of Alcohol-Associated Liver Disease

Excessive alcohol consumption is a global healthcare problem with enormous social, economic, and clinical consequences. While chronic, heavy alcohol consumption causes structural damage and/or disrupts normal organ function in virtually every tissue of the body, the liver sustains the greatest damage. This is primarily because the liver is the first to see alcohol absorbed from the gastrointestinal tract via the portal circulation and second, because the liver is the principal site of ethanol metabolism. Alcohol-induced damage remains one of the most prevalent disorders of the liver and a leading cause of death or transplantation from liver disease. Despite extensive research on the pathophysiology of this disease, there are still no targeted therapies available. Given the multifactorial mechanisms for alcohol-associated liver disease pathogenesis, it is conceivable that a multitherapeutic regimen is needed to treat different stages in the spectrum of this disease.

Liver-specific drug delivery platforms: Applications for the treatment of alcohol-associated liver disease

Alcohol-associated liver disease (ALD) is a common chronic liver disease and major contributor to liver disease-related deaths worldwide. Despite its pre-valence, there are few effective pharmacological options for the severe stages of this disease. While much pre-clinical research attention is paid to drug development in ALD, many of these experimental therapeutics have limitations such as poor pharmacokinetics, poor efficacy, or off-target side effects due to systemic administration. One means of addressing these limitations is through liver-targeted drug delivery, which can be accomplished with different platforms including liposomes, polymeric nanoparticles, exosomes, bacteria, and adeno-associated viruses, among others. These platforms allow drugs to target the liver passively or actively, thereby reducing systemic circulation and increasing the ‘effective dose’ in the liver. While many studies, some clinical, have applied targeted delivery systems to other liver diseases such as viral hepatitis or hepatocellular carcinoma, only few have investigated their efficacy in ALD. This review provides basic information on these liver-targeting drug delivery platforms, including their benefits and limitations, and summarizes the current research efforts to apply them to the treatment of ALD in rodent models. We also discuss gaps in knowledge in the field, which when addressed, may help to increase the efficacy of novel therapies and better translate them to humans.

Mongolian medicine in treating type 2 diabetes mellitus combined with nonalcoholic fatty liver disease via FXR/LXR-mediated P2X7R/NLRP3/NF-κB pathway activation

Type 2 diabetes mellitus (T2DM) and nonalcoholic fatty liver disease (NAFLD) are the most problematic metabolic diseases in the world. NAFLD encompasses a spectrum of severity, ranging from simple steatosis to non-alcoholic steatohepatitis (NASH) and fibrosis, increasing the risk of cirrhosis and hepatocellular carcinoma. Importantly, NAFLD is closely linked to obesity and tightly interrelated with insulin resistance and T2DM. T2DM and NAFLD (T2DM-NAFLD) are called as the Xike Rixijing Disease and Tonglaga Indigestion Disease respectively, in Mongolian medicine. Xike Rixijing Disease maybe develop into Tonglaga Indigestion Disease. Forturnately many Mongolian medicines show efficient treatment of T2DM-NAFLD, such as Agriophyllum squarrosum, Haliyasu (dried powder of camel placenta), Digeda-4 (herbs of Lomatogonium carinthiacum, rhizomata of Coptis chinensis, ripe fruits of Gardenia jasminoides, herbs of Dianthus superbus), Guangmingyan Siwei Decoction Powder (Halite, ripe fruits of Terminalia chebula, rhizomata of Zingiber officinale, fruit clusters of Piper longum), Tonglaga-5 (ripe fruits of Punica granatum, barks of Cinnamomum cassia, ripe fruits of Amomum kravanh, fruit clusters of Piper longum, flowers of Carthamus tinctorius), Tegexidegeqi (rhizomata of Inula helenium, ripe fruits of Gardenia jasminoides, rhizomata of Platycodon grandiflorum, rhizomata of Coptis chinensis, heartwood of Caesalpinia sappan), Ligan Shiliu Bawei San (ripe fruits of Punica granatum, barks of Cinnamomum cassia, ripe fruits of Amomum kravanh, fruit clusters of Piper longum, flowers of Carthamus tinctorius, ripe fruits of Amomum tsao-ko, rhizomata of Zingiber officinale), etc. Principles of Mongolian medicine in treating diseases: by balancing “three essences or roots” and “seven elements”, strengthening liver and kidney function, transporting nutrients to enhance physical strength and disease resistance, and combined with drugs for comprehensive conditioning treatment. However, their molecular mechanisms remain unclear. In this review, we prospect that Mongolian medicines might be a promising treatment for T2DM-NAFLD by activating P2X7R/NLRP3/NF-κB inflammatory pathway via lipid-sensitive nuclear receptors (i.e., FXR and LXR).

Myristic Acid Supplementation Aggravates High Fat Diet-Induced Adipose Inflammation and Systemic Insulin Resistance in Mice

Saturated fatty acids (SFAs) are considered to be detrimental to human health. One of the SFAs, myristic acid (MA), is known to exert a hypercholesterolemic effect in mice as well as humans. However, its effects on altering adipose tissue (AT) inflammation and systemic insulin resistance (IR) in obesity are still unclear. Here, we sought to determine the effects of a high fat (HF) diet supplemented with MA on obesity-associated metabolic disorders in mice. Wild-type C57BL/6 mice were fed a HF diet in the presence or absence of 3% MA for 12 weeks. Plasma lipids, plasma adipokines, AT inflammation, systemic IR, glucose homeostasis, and hepatic steatosis were assessed. The body weight and visceral adipose tissue (VAT) mass were significantly higher in mice receiving the HF+MA diet compared to HF diet-fed controls. Plasma total cholesterol levels were marginally increased in HF+MA-fed mice compared to controls. Fasting blood glucose was comparable between HF and HF+MA-fed mice. Interestingly, the plasma insulin and HOMA-IR index, a measure of insulin resistance, were significantly higher in HF+MA-fed mice compared to HF controls. Macrophage and inflammatory markers were significantly elevated in the AT and AT-derived stromal vascular cells upon MA feeding. Moreover, the level of circulating resistin, an adipokine promoting insulin resistance, was significantly higher in HF+MA-fed mice compared with HF controls. The insulin tolerance test revealed that the IR was higher in mice receiving the MA supplementation compared to HF controls. Moreover, the glucose tolerance test showed impairment in systemic glucose homeostasis in MA-fed mice. Analyses of liver samples showed a trend towards an increase in liver TG upon MA feeding. However, markers of oxidative stress and inflammation were reduced in the liver of mice fed an MA diet compared to controls. Taken together, our data suggest that chronic administration of MA in diet exacerbates obesity-associated insulin resistance and this effect is mediated in part, via increased AT inflammation and increased secretion of resistin.

Therapeutic Potential of Superoxide Dismutase Fused with Cell-Penetrating Peptides in Oxidative Stress-Related Diseases

Superoxide dismutase (SOD) is a well-known cellular antioxidant enzyme. However, exogenous SOD cannot be used to protect tissues from oxidative damage due to the low permeability of the cell membrane. Cell-penetrating peptides (CPPs) are a class of short peptides that can cross the cell membrane. Recombinant fusion protein that fuses SOD protein with CPP (CPP-SOD) can cross various tissues and organs as well as the blood-brain barrier. CPP-SODs can relieve severe oxidative damage in various tissues caused by radiation, ischemia, inflammation, and chemotherapy by clearing the reactive oxygen species, reducing the expression of inflammatory factors, and inhibiting NF-κB/MAPK signaling pathways. Therefore, the clinical application of CPP-SODs provide new therapeutic strategies for a variety of oxidative stress-related disorders, such as Parkinson's disease, diabetes, obesity, cardiac fibrosis, and premature aging.

Targeting lipophagy as a potential therapeutic strategy for nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is becoming an increasingly serious disease worldwide. Unfortunately, no specific drug has been approved to treat NAFLD. Accumulating evidence suggests that lipotoxicity, which is induced by an excess of intracellular triacylglycerols (TAGs), is a potential mechanism underlying the ill-defined progression of NAFLD. Under physiological conditions, a balance is maintained between TAGs and free fatty acids (FFAs) in the liver. TAGs are catabolized to FFAs through neutral lipolysis and/or lipophagy, while FFAs can be anabolized to TAGs through an esterification reaction. However, in the livers of patients with NAFLD, lipophagy appears to fail. Reversing this abnormal state through several lipophagic molecules (mTORC1, AMPK, PLIN, etc.) facilitates NAFLD amelioration; therefore, restoring failed lipophagy may be a highly efficient therapeutic strategy for NAFLD. Here, we outline the lipophagy phases with the relevant important proteins and discuss the roles of lipophagy in the progression of NAFLD. Additionally, the potential candidate drugs with therapeutic value targeting these proteins are discussed to show novel strategies for future treatment of NAFLD.

Harnessing reactive oxygen/nitrogen species and inflammation: Nanodrugs for liver injury

Overall, 12% of the global population (800 million) suffers from liver disease, which causes 2 million deaths every year. Liver injury involving characteristic reactive oxygen/nitrogen species (RONS) and inflammation plays a key role in progression of liver disease. As a key metabolic organ of the human body, the liver is susceptible to injury from various sources, including COVID-19 infection. Owing to unique structural features and functions of the liver, most current antioxidants and anti-inflammatory drugs are limited against liver injury. However, the characteristics of the liver could be utilized in the development of nanodrugs to achieve specific enrichment in the liver and consequently targeted treatment. Nanodrugs have shown significant potential in eliminating RONS and regulating inflammation, presenting an attractive therapeutic tool for liver disease through controlling liver injury. Therefore, the main aim of the current review is to provide a comprehensive summary of the latest developments contributing to our understanding of the mechanisms underlying nanodrugs in the treatment of liver injury via harnessing RONS and inflammation. Meanwhile, the prospects of nanodrugs for liver injury therapy are systematically discussed, which provides a sound platform for novel therapeutic insights and inspiration for design of nanodrugs to treat liver disease.

A review of the role of ethanol-induced adipose tissue dysfunction in alcohol-associated liver disease

Alcohol-associated liver disease (AALD) encompasses a spectrum of liver diseases that includes simple steatosis, steatohepatitis, fibrosis, and cirrhosis. The adverse effects of alcohol in liver and the mechanisms by which ethanol (EtOH) promotes liver injury are well studied. Although liver is known to be the primary organ affected by EtOH exposure, alcohol's effects on other organs are also known to contribute significantly to the development of liver injury. It is becoming increasingly evident that adipose tissue (AT) is an important site of EtOH action. Both AT storage and secretory functions are altered by EtOH. For example, AT lipolysis, stimulated by EtOH, contributes to chronic alcohol-induced hepatic steatosis. Adipocytes secrete a wide variety of biologically active molecules known as adipokines. EtOH alters the secretion of these adipokines from AT, which include cytokines and chemokines that exert paracrine effects in liver. In addition, the level of EtOH-metabolizing enzymes, in particular, CYP2E1, rises in the AT of EtOH-fed mice, which promotes oxidative stress and/or inflammation in AT. Thus, AT dysfunction characterized by increased AT lipolysis and free fatty acid mobilization and altered secretion of adipokines can contribute to the severity of AALD. Of note, moderate EtOH exposure results in AT browning and activation of brown adipose tissue which, in turn, can promote thermogenesis. In this review article, we discuss the direct effects of EtOH consumption in AT and the mechanisms by which EtOH impacts the functions of AT, which, in turn, increases the severity of AALD in animal models and humans.

Biochemical Mechanisms Associating Alcohol Use Disorders with Cancers

Simple Summary

Of all yearly deaths attributable to alcohol consumption globally, approximately 12% are due to cancers, representing approximately 0.4 million deceased individuals. Ethanol metabolism disturbs cell biochemistry by targeting the structure and function of essential biomolecules (proteins, nucleic acids, and lipids) and by provoking alterations in cell programming that lead to cancer development and cancer malignancy. A better understanding of the metabolic and cell signaling realm affected by ethanol is paramount to designing effective treatments and preventive actions tailored to specific neoplasias.

Abstract

The World Health Organization identifies alcohol as a cause of several neoplasias of the oropharynx cavity, esophagus, gastrointestinal tract, larynx, liver, or female breast. We review ethanol’s nonoxidative and oxidative metabolism and one-carbon metabolism that encompasses both redox and transfer reactions that influence crucial cell proliferation machinery. Ethanol favors the uncontrolled production and action of free radicals, which interfere with the maintenance of essential cellular functions. We focus on the generation of protein, DNA, and lipid adducts that interfere with the cellular processes related to growth and differentiation. Ethanol’s effects on stem cells, which are responsible for building and repairing tissues, are reviewed. Cancer stem cells (CSCs) of different origins suffer disturbances related to the expression of cell surface markers, enzymes, and transcription factors after ethanol exposure with the consequent dysregulation of mechanisms related to cancer metastasis or resistance to treatments. Our analysis aims to underline and discuss potential targets that show more sensitivity to ethanol’s action and identify specific metabolic routes and metabolic realms that may be corrected to recover metabolic homeostasis after pharmacological intervention. Specifically, research should pay attention to re-establishing metabolic fluxes by fine-tuning the functioning of specific pathways related to one-carbon metabolism and antioxidant processes.

Superoxide Dismutase Administration: A Review of Proposed Human Uses

Superoxide dismutases (SODs) are metalloenzymes that play a major role in antioxidant defense against oxidative stress in the body. SOD supplementation may therefore trigger the endogenous antioxidant machinery for the neutralization of free-radical excess and be used in a variety of pathological settings. This paper aimed to provide an extensive review of the possible uses of SODs in a range of pathological settings, as well as describe the current pitfalls and the delivery strategies that are in development to solve bioavailability issues. We carried out a PubMed query, using the keywords "SOD", "SOD mimetics", "SOD supplementation", which included papers published in the English language, between 2012 and 2020, on the potential therapeutic applications of SODs, including detoxification strategies. As highlighted in this paper, it can be argued that the generic antioxidant effects of SODs are beneficial under all tested conditions, from ocular and cardiovascular diseases to neurodegenerative disorders and metabolic diseases, including diabetes and its complications and obesity. However, it must be underlined that clinical evidence for its efficacy is limited and consequently, this efficacy is currently far from being demonstrated.

Effects of Ethanol Feeding in Early-Stage NAFLD Mice Induced by Western Diet

Background: The prevalence of metabolic liver diseases is increasing and approved pharmacological treatments are still missing. Many animal models of nonalcoholic fatty liver disease (NAFLD) show a full spectrum of fibrosis, inflammation and steatosis, which does not reflect the human situation since only up to one third of the patients develop fibrosis and nonalcoholic steatohepatitis (NASH). Methods: Seven week old C57Bl/J mice were treated with ethanol, Western diet (WD) or both. The animals’ liver phenotypes were determined through histology, immunohistochemistry, Western blotting, hepatic triglyceride content and gene expression levels. In a human cohort of 80 patients stratified by current alcohol misuse and body mass index, liver histology and gene expression analysis were performed. Results: WD diet and ethanol-treated animals showed severe steatosis, with high hepatic triglyceride content and upregulation of fatty acid synthesis. Mild fibrosis was revealed using Sirius-red stains and gene expression levels of collagen. Inflammation was detected using histology, immunohistochemistry and upregulation of proinflammatory genes. The human cohort of obese drinkers showed similar upregulation in genes related to steatosis, fibrosis and inflammation. Conclusions: We provide a novel murine model for early-stage fatty liver disease suitable for drug testing and investigation of pathophysiology.

Experimental models of metabolic and alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a multi-systemic disease that is considered the hepatic manifestation of metabolic syndrome (MetS). Because alcohol consumption in NAFLD patients is common, there is a significant overlap in the pathogenesis of NAFLD and alcoholic liver disease (ALD). Indeed, MetS also significantly contributes to liver injury in ALD patients. This “syndrome of metabolic and alcoholic steatohepatitis” (SMASH) is thus expected to be a more prevalent presentation in liver patients, as the obesity epidemic continues. Several pre-clinical experimental models that couple alcohol consumption with NAFLD-inducing diet or genetic obesity have been developed to better understand the pathogenic mechanisms of SMASH. These models indicate that concomitant MetS and alcohol contribute to lipid dysregulation, oxidative stress, and the induction of innate immune response. There are significant limitations in the applicability of these models to human disease, such as the ability to induce advanced liver injury or replicate patterns in human food/alcohol consumption. Thus, there remains a need to develop models that accurately replicate patterns of obesogenic diet and alcohol consumption in SMASH patients.