The adverse effects of alcohol on vitamin A metabolism

Altered gut microbe metabolites in patients with alcohol‑induced osteonecrosis of the femoral head: An integrated omics analysis

Excessive alcohol consumption is considered to be a major risk factor of alcohol-induced osteonecrosis of the femoral head (AONFH). The gut microbiota (GM) has been reported to aid in the regulation of human physiology and its composition can be altered by alcohol consumption. The aim of the present study was to improve the understanding of the GM and its metabolites in patients with AONFH. Metabolomic sequencing and 16S rDNA analysis of fecal samples were performed using liquid chromatography-mass spectrometry to characterize the GM of patients with AONFH and healthy normal controls (NCs). Metagenomic sequencing of fecal samples was performed to identify whether GM changes on the species level were associated with the expression of gut bacteria genes or their associated functions in patients with AONFH. The abundance of 58 genera was found to differ between the NC group and the AONFH group. Specifically, Klebsiella, Holdemanella, Citrobacter and Lentilactobacillus were significantly more abundant in the AONFH group compared with those in the NC group. Metagenomic sequencing demonstrated that the majority of the bacterial species that exhibited significantly different abundance in patients with AONFH belonged to the genus Pseudomonas. Fecal metabolomic analysis demonstrated that several metabolites were present at significantly different concentrations in the AONFH group compared with those in the NC group. These metabolites were products of vitamin B6 metabolism, retinol metabolism, pentose and glucuronate interconversions and glycerophospholipid metabolism. In addition, these changes in metabolite levels were observed to be associated with the altered abundance of specific bacterial species, such as Basidiobolus, Mortierella, Phanerochaete and Ceratobasidium. According to the results of the present study, a comprehensive landscape of the GM and metabolites in patients with AONFH was revealed, suggesting the existence of interplay between the gut microbiome and metabolome in AONFH pathogenesis.

Natural products for the treatment of age-related macular degeneration

BACKGROUND

Age-related macular degeneration (AMD) is a chronic retinal disease that significantly influences the vision of the elderly.

PURPOSE

There is no effective treatment and prevention method. The pathogenic process behind AMD is complex, including oxidative stress, inflammation, and neovascularization. It has been demonstrated that several natural products can be used to manage AMD, but systematic summaries are lacking.

STUDY DESIGN AND METHODS

PubMed, Web of Science, and ClinicalTrials.gov were searched using the keywords "Biological Products" AND "Macular Degeneration" for studies published within the last decade until May 2023 to summarize the latest findings on the prevention and treatment of age-related macular degeneration through the herbal medicines and functional foods.

RESULTS

The eligible studies were screened, and the relevant information about the therapeutic action and mechanism of natural products used to treat AMD was extracted. Our findings demonstrate that natural substances, including retinol, phenols, and other natural products, prevent the development of new blood vessels and protect the retina from oxidative stress in cells and animal models. However, they have barely been examined in clinical studies.

CONCLUSION

Natural products could be highly prospective candidate drugs used to treat AMD, and further preclinical and clinical research is required to validate it to control the disease.

Modest effect of differential dietary vitamin A intake on the pathogenesis of alcohol-associated liver disease

BACKGROUND

Chronic alcohol consumption is a major public health issue. The primary organ damaged by alcohol abuse is the liver, leading to alcohol-associated liver disease (ALD). ALD begins with hepatic steatosis and can progress to fibrosis and cirrhosis; however, we have an incomplete understanding of ALD pathogenesis. Interestingly, the liver is also the major organ for vitamin A metabolism and storage, and ALD has previously been linked with altered hepatic vitamin A homeostasis. We hypothesize that alcohol-induced vitamin A depletion disrupts its normal function in the liver, contributing to the pathogenesis of ALD. To test this hypothesis, we postulated that adding copious vitamin A to the diet might alleviate ALD, and conversely, that a vitamin A deficient diet would worsen ALD.

METHODS

We conducted two dietary intervention studies in mice comparing deficient (0 IU/g diet) and copious (25 IU/g diet) dietary vitamin A intake versus control (4 IU/g diet), using the NIAAA chronic-binge model of ALD. Hepatic steatosis was assessed using histopathological and biochemical approaches. Tissue Vitamin A levels were measured using high-performance liquid chromatography. Markers of ALD, hepatic inflammation and lipid metabolism were analyzed by the quantitative polymerase chain reaction and western blotting.

RESULTS

As expected, a 0 IU/g Vitamin A diet decreased, and a 25 IU/g Vitamin A diet increased hepatic Vitamin A stores. However, alcohol induced changes in hepatic triglyceride levels, markers of hepatic lipid metabolism, inflammation and fibrosis were not significantly different in mice consuming a copious or deficient vitamin A diet compared to control.

CONCLUSIONS

Altered vitamin A intake and hepatic vitamin A storage have a minor effect on the pathogenesis of ALD. Thus, given the known link between altered retinoic acid signaling and ALD, future studies that further explore this linkage are warranted.

Interaction between fatty acid oxidation and ethanol metabolism in liver

Fatty acid oxidation (FAO) releases the energy stored in fat to maintain basic biological processes. Dehydrogenation is a major way to oxidize fatty acids, which needs NAD+ to accept the released H+ from fatty acids and form NADH, which increases the ratio of NADH/NAD+ and consequently inhibits FAO leading to the deposition of fat in the liver, which is termed fatty liver or steatosis. Consumption of alcohol (ethanol) initiates simple steatosis that progresses to alcoholic steatohepatitis, which constitutes a spectrum of liver disorders called alcohol-associated liver disease (ALD). ALD is linked to ethanol metabolism. Ethanol is metabolized by alcohol dehydrogenase (ADH), microsomal ethanol oxidation system (MEOS), mainly cytochrome P450 2E1 (CYP2E1), and catalase. ADH also requires NAD+ to accept the released H+ from ethanol. Thus, ethanol metabolism by ADH leads to increased ratio of NADH/NAD+, which inhibits FAO and induces steatosis. CYP2E1 directly consumes reducing equivalent NADPH to oxidize ethanol, which generates reactive oxygen species (ROS) that lead to cellular injury. Catalase is mainly present in peroxisomes, where very long-chain fatty acids and branched-chain fatty acids are oxidized, and the resultant short-chain fatty acids will be further oxidized in mitochondria. Peroxisomal FAO generates hydrogen peroxide (H2O2), which is locally decomposed by catalase. When ethanol is present, catalase uses H2O2 to oxidize ethanol. In this review, we introduce FAO (including α-, β-, and ω-oxidation) and ethanol metabolism (by ADH, CYP2E1, and catalase) followed by the interaction between FAO and ethanol metabolism in the liver and its pathophysiological significance.

Malnutrition is associated with poor survival in women receiving radiotherapy for cervical cancer

OBJECTIVE

Cancer patients are at risk of malnutrition, which is associated with poor oncological outcomes. The aim of this study was to assess the incidence of malnutrition before, during, and after radiotherapy in locally advanced cervical cancer patients. In addition, we evaluated the impact of malnutrition on survival, and whether and when malnourished patients were referred to a dietitian.

METHODS

This retrospective cohort study included cervical cancer patients who received primary or adjuvant radiotherapy with curative intent between January 2013 and January 2021. Patient and treatment characteristics, including longitudinal data on weight and dietary care, were retrieved from the electronic patient files. Malnutrition was defined by body mass index and weight loss according to the Global Leadership Initiative on Malnutrition (GLIM). Overall survival was estimated using the Kaplan-Meier method. Cox proportional hazard regression analysis was used to estimate hazard ratios for key prognostic factors.

RESULTS

A total of 294 patients were included. Median follow-up was 40 months (range 7-101 months). Malnutrition occurred in 44 patients (15%) at baseline, in 132 (45%) during radiotherapy, and in 63 (21%) during follow-up. Referral to a dietician occurred in 45% of the 138 patients who were malnourished before or during radiotherapy. Malnutrition was significantly associated with worse survival after adjusting for age, performance score, diabetes, histology, International Federation of Gynecology and Obstetrics (FIGO) stage, and nodal stage. The 3 year overall survival in patients with malnutrition was 77% (95% confidence interval (CI) 70% to 85%) and without malnutrition 89% (95% CI 83% to 95%); p=0.001). Independent significant risk factors for worse overall survival were: malnutrition, age ˃52 years, adenocarcinoma, FIGO stage III/IV, and N1 disease.

CONCLUSION

Malnutrition was common in cervical cancer patients treated with radiotherapy and was associated with a shorter overall survival. Further studies are needed to evaluate the effectiveness of better monitoring of malnutrition and faster and better dietary intervention on survival and quality of life.

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.

Retinoic Acid Receptor β Loss in Hepatocytes Increases Steatosis and Elevates the Integrated Stress Response in Alcohol-Associated Liver Disease

In alcohol-associated liver disease (ALD), hepatic reductions in vitamin A and perturbations in vitamin A metabolism are common. However, the roles that the vitamin A receptors, termed retinoic acid receptors (RARs), may have in preventing the pathophysiology of ALD remains unclear. Our prior data indicate that a RARβ agonist limits the pathology of alcohol-related liver disease. Thus, we generated liver-specific AlbCre-RARβ knockout (BKO) mice and compared them to wild type (WT) mice in an early ALD model. Both strains showed similar blood ethanol concentrations and ETOH-metabolizing enzymes. However, the livers of pair-fed-BKO and ETOH-BKO mice developed higher levels of steatosis and triglycerides than pair-fed-WT and ETOH-WT mice. The increased hepatic steatosis observed in the pair-fed-BKO and ETOH-BKO mice was associated with higher lipid synthesis/trafficking transcripts and lower beta-oxidation transcripts. ETOH-BKO mice also exhibited a higher integrated stress response (ISR) signature, including higher transcript and protein levels of ATF4 and its target, 4-EBP1. In human hepatocytes (HepG2) that lack RARβ (RARβ-KO), ETOH treatments resulted in greater reactive oxygen species compared to their parental cells. Notably, even without ETOH, ATF4 and 4-EBP1 protein levels were higher in the RARβ-KO cells than in their parental cells. These 4-EBP1 increases were greatly attenuated in cultured ATF4-deficient and RARβ/ATF4-deficient HepG2, suggesting that RARβ is a crucial negative regulator of 4-EBP1 through ATF4 in cultured hepatocytes. Here, we identify RARβ as a negative regulator of lipid metabolism and cellular stress in ALD.

Investigation of selective retinoic acid receptor alpha antagonist ER-50891 and related analogs for male contraception

Retinoic acid receptor alpha (RARα) antagonist ER-50891 and 15 analogs were prepared and tested in vitro for potency and selectivity at RARα, RARβ, and RARγ using transactivation assays. Minor modifications to the parent molecule such as the introduction of a C4 tolyl group in place of the C4 phenyl group on the quinoline moiety slightly increased the RARα selectivity but larger substituents significantly decreased the potency. Replacement of the pyrrole moiety of ER-50891 with triazole, amides, or a double bond produced inactive compounds. ER-50891 was found to be stable in male mouse liver microsomes and was tested in male mice to assess its effects on spermatogenesis. Characteristic, albeit modest and transient, effects on spermatogenesis were observed.

Nutritional Support for Alcoholic Liver Disease

Malnutrition is a common finding in alcohol use disorders and is associated with the prognosis of patients with alcoholic liver disease (ALD). These patients also frequently show deficiencies in vitamins and trace elements, increasing the likelihood of anemia and altered cognitive status. The etiology of malnutrition in ALD patients is multifactorial and complex and includes inadequate dietary intake, abnormal absorption and digestion, increased skeletal and visceral protein catabolism, and abnormal interactions between ethanol and lipid metabolism. Most nutritional measures derive from general chronic liver disease recommendations. Recently, many patients with ALD have been diagnosed with metabolic syndrome, which requires individualized treatment via nutritional therapy to avoid overnutrition. As ALD progresses to cirrhosis, it is frequently complicated by protein–energy malnutrition and sarcopenia. Nutritional therapy is also important in the management of ascites and hepatic encephalopathy as liver failure progresses. The purpose of the review is to summarize important nutritional therapies for the treatment of ALD.

Acute and chronic blood serum proteome changes in patients with methanol poisoning

Twenty-four blood serum samples from patients with acute methanol poisoning (M) from the mass methanol poisoning outbreak in the Czech Republic in 2012 were compared with 46 patient samples taken four years after poisoning (S) (overlap of 10 people with group M) and with a control group (C) of 24 samples of patients with a similar proportion of chronic alcohol abuse. When comparing any two groups, tens to hundreds of proteins with a significant change in concentration were identified. Fifteen proteins showed significant changes when compared between any two groups. The group with acute methanol poisoning showed significant changes in protein concentrations for at least 64 proteins compared to the other groups. Among the most important identified proteins closely related to intoxication are mainly those involved in blood coagulation, metabolism of vitamin A (increased retinol-binding protein), immune response (e.g., increased complement factor I, complement factors C3 and C5), and lipid transport (increased apolipoprotein A I, apolipoprotein A II, adiponectin). For blood coagulation, the most affected proteins with significant changes in the methanol poisoning group were von Willebrand factor, carboxypeptidase N, alpha-2-antiplasmin (all increased), inter-alpha-trypsin inhibitor heavy chain H4, kininogen-1, plasma serine protease inhibitor, plasminogen (all decreased). However, heparin administration used for the methanol poisoning group could have interfered with some of the changes in their concentrations. Data are available via ProteomeXchange with the identifier PXD035726.

Disruption of vitamin A homeostasis by the biocide tetrakis(hydroxymethyl) phosphonium sulphate in pregnant rabbits

The biocide tetrakis(hydroxymethyl)phosphonium sulphate (THPS) and other members of the tetrakis(hydroxymethyl) phosphonium salts (THPX) family are associated with liver toxicity in several mammalian species and teratogenicity in rabbits. Malformations include skeletal changes and abnormalities in eye development and are very similar to those seen with vitamin A deficiency or excess. For this reason, it was hypothesized that teratogenicity of THPS(X) might be attributed to disturbances in retinol availability and/or metabolism as a result of maternal toxicity, for example, either due to insufficient dietary intake by the mothers or due to liver toxicity. Therefore, in the present study, liver toxicity and vitamin A homeostasis were studied in pregnant rabbits that were exposed to 13.8 or 46.0 mg/kg THPS during organogenesis and in precision-cut liver slices of rats and rabbits exposed to 0-70 μM THPS. Results show that in vivo exposure to THPS leads to a marked reduction of food intake, increased plasma concentrations of γ-glutamytransferase, degenerative changes in the liver and to changes in retinoid content in liver and plasma in the rabbits during organogenesis. In addition, THPS, both in vivo and ex vivo, caused a change in expression of proteins related to vitamin A metabolism and transport. Together, these observations could explain the birth defects observed in earlier teratogenicity studies.

Main nutritional deficiencies

Nutrition is the source of energy that is required to carry out all the processes of human body. A balanced diet is a combination of both macro- and micronutrients. "Nutritional inadequacy" involves an intake of nutrients that is lower than the estimated average requirement, whereas "nutritional deficiency" consists of severely reduced levels of one or more nutrients, making the body unable to normally perform its functions and thus leading to an increased risk of several diseases like cancer, diabetes, and heart disease. Malnutrition could be caused by environmental factors, like food scarcity, as well as disease conditions, like anorexia nervosa, fasting, swallowing inability, persistent vomiting, impaired digestion, intestinal malabsorption, or other chronic diseases. Nutritional biomarkers - like serum or plasma levels of nutrients such as folate, vitamin C, B vitamins, vitamin D, selenium, copper, zinc - could be used for the evaluation of nutrient intake and dietary exposure. Macronutrients deficiencies could cause kwashiorkor, marasmus, ketosis, growth retardation, wound healing, and increased infection susceptibility, whereas micronutrient - like iron, folate, zinc, iodine, and vitamin A - deficiencies lead to intellectual impairment, poor growth, perinatal complications, degenerative diseases associated with aging and higher morbidity and mortality. Preventing macro- and micronutrient deficiency is crucial and this could be achieved through supplementation and food-based approaches.

ESPEN micronutrient guideline

BACKGROUND

Trace elements and vitamins, named together micronutrients (MNs), are essential for human metabolism. Recent research has shown the importance of MNs in common pathologies, with significant deficiencies impacting the outcome.

OBJECTIVE

This guideline aims to provide information for daily clinical nutrition practice regarding assessment of MN status, monitoring, and prescription. It proposes a consensus terminology, since many words are used imprecisely, resulting in confusion. This is particularly true for the words "deficiency", "repletion", "complement", and "supplement".

METHODS

The expert group attempted to apply the 2015 standard operating procedures (SOP) for ESPEN which focuses on disease. However, this approach could not be applied due to the multiple diseases requiring clinical nutrition resulting in one text for each MN, rather than for diseases. An extensive search of the literature was conducted in the databases Medline, PubMed, Cochrane, Google Scholar, and CINAHL. The search focused on physiological data, historical evidence (published before PubMed release in 1996), and observational and/or randomized trials. For each MN, the main functions, optimal analytical methods, impact of inflammation, potential toxicity, and provision during enteral or parenteral nutrition were addressed. The SOP wording was applied for strength of recommendations.

RESULTS

There was a limited number of interventional trials, preventing meta-analysis and leading to a low level of evidence. The recommendations underwent a consensus process, which resulted in a percentage of agreement (%): strong consensus required of >90% of votes. Altogether the guideline proposes sets of recommendations for 26 MNs, resulting in 170 single recommendations. Critical MNs were identified with deficiencies being present in numerous acute and chronic diseases. Monitoring and management strategies are proposed.

CONCLUSION

This guideline should enable addressing suboptimal and deficient status of a bundle of MNs in at-risk diseases. In particular, it offers practical advice on MN provision and monitoring during nutritional support.

Retinoids in the Pathogenesis and Treatment of Liver Diseases

Vitamin A (VA), all-trans-retinol (ROL), and its analogs are collectively called retinoids. Acting through the retinoic acid receptors RARα, RARβ, and RARγ, all-trans-retinoic acid, an active metabolite of VA, is a potent regulator of numerous biological pathways, including embryonic and somatic cellular differentiation, immune functions, and energy metabolism. The liver is the primary organ for retinoid storage and metabolism in humans. For reasons that remain incompletely understood, a body of evidence shows that reductions in liver retinoids, aberrant retinoid metabolism, and reductions in RAR signaling are implicated in numerous diseases of the liver, including hepatocellular carcinoma, non-alcohol-associated fatty liver diseases, and alcohol-associated liver diseases. Conversely, restoration of retinoid signaling, pharmacological treatments with natural and synthetic retinoids, and newer agonists for specific RARs show promising benefits for treatment of a number of these liver diseases. Here we provide a comprehensive review of the literature demonstrating a role for retinoids in limiting the pathogenesis of these diseases and in the treatment of liver diseases.

A retinoic acid receptor β2 agonist protects against alcohol liver disease and modulates hepatic expression of canonical retinoid metabolism genes

Alcohol abuse reduces hepatic vitamin A (retinoids), reductions that are associated with progression of alcohol liver disease (ALD). Restoring hepatic retinoids through diet is contraindicated in ALD due to the negative effects of alcohol on retinoid metabolism. There are currently no drugs that can both mitigate alcohol-driven hepatic retinoid losses and progression of ALD. Using a mouse model of alcohol intake, we examined if an agonist for the retinoic acid (RA) receptor β2 (RARβ2), AC261066 (AC261) could prevent alcohol-driven hepatic retinoid losses and protect against ALD. Our results show that mice co-treated with AC261 and alcohol displayed mitigation of ALD, including reduced macro, and microvesicular steatosis, and liver damage. Alcohol intake led to increases in hepatic centrilobular levels of ALDH1A1, a rate-limiting enzyme in RA synthesis, and co-localization of ALDH1A1 with the alcohol-metabolizing enzyme CYP2E1, and 4-HNE, a marker of oxidative stress; expression of these targets was abrogated in mice co-treated with AC261 and alcohol. By RNA sequencing technology, we found that AC261 treatments opposed alcohol modulation of 68 transcripts involved in canonical retinoid metabolism. Alcohol modulation of these transcripts, including CES1D, CES1G, RBP1, RDH10, and CYP26A1, collectively favor hepatic retinoid hydrolysis and catabolism. However, despite this, co-administration of AC261 with alcohol did not mitigate alcohol-mediated depletions of hepatic retinoids, but did reduce alcohol-driven increases in serum retinol. Our data show that AC261 protected mice against ALD, even though AC261 did not prevent alcohol-mediated reductions in hepatic retinoids. These data warrant further studies of the anti-ALD properties of AC261.

Alcohol induced hepatic retinoid depletion is associated with the induction of multiple retinoid catabolizing cytochrome P450 enzymes

Chronic alcohol consumption leads to a spectrum of liver disease that is associated with significant global mortality and morbidity. Alcohol is known to deplete hepatic vitamin A content, which has been linked to the pathogenesis of alcoholic liver disease. It has been suggested that induction of Cytochrome P450 2E1 (CYP2E1) contributes to alcohol-induced hepatic vitamin A depletion, but the possible contributions of other retinoid-catabolizing CYPs have not been well studied. The main objective of this study was to better understand alcohol-induced hepatic vitamin A depletion and test the hypothesis that alcohol-induced depletion of hepatic vitamin A is due to CYP-mediated oxidative catabolism. This hypothesis was tested in a mouse model of chronic alcohol consumption, including wild type and Cyp2e1 -/- mice. Our results show that chronic alcohol consumption is associated with decreased levels of hepatic retinol, retinyl esters, and retinoic acid. Moreover, the depletion of hepatic retinoid is associated with the induction of multiple retinoid catabolizing CYPs, including CYP26A1, and CYP26B1 in alcohol fed wild type mice. In Cyp2e1 -/- mice, alcohol-induced retinol decline is blunted but retinyl esters undergo a change in their acyl composition and decline upon alcohol exposure like WT mice. In conclusion, the alcohol induced decline in hepatic vitamin A content is associated with increased expression of multiple retinoid-catabolizing CYPs, including the retinoic acid specific hydroxylases CYP26A1 and CYP26B1.

Iron and iron-related proteins in alcohol consumers: cellular and clinical aspects

Alcohol-associated liver disease (ALD) is one of the most common chronic liver diseases. Its pathological spectrum includes the overlapping stages of hepatic steatosis/steatohepatitis that can progress to liver fibrosis and cirrhosis; both are risk factors for hepatocellular carcinoma. Moreover, ALD diagnosis and management pose several challenges. The early pathological stages are reversible by alcohol abstinence, but these early stages are often asymptomatic, and currently, there is no specific laboratory biomarker or diagnostic test that can confirm ALD etiology. Alcohol consumers frequently show dysregulation of iron and iron-related proteins. Examination of iron-related parameters in this group may aid in early disease diagnosis and better prognosis and management. For this, a coherent overview of the status of iron and iron-related proteins in alcohol consumers is essential. Therefore, here, we collated and reviewed the alcohol-induced alterations in iron and iron-related proteins. Reported observations include unaltered, increased, or decreased levels of hemoglobin and serum iron, increments in intestinal iron absorption (facilitated via upregulations of duodenal divalent metal transporter-1 and ferroportin), serum ferritin and carbohydrate-deficient transferrin, decrements in serum hepcidin, decreased or unaltered levels of transferrin, increased or unaltered levels of transferrin saturation, and unaltered levels of soluble transferrin receptor. Laboratory values of iron and iron-related proteins in alcohol consumers are provided for reference. The causes and mechanisms underlying these alcohol-induced alterations in iron parameters and anemia in ALD are explained. Notably, alcohol consumption by hemochromatosis (iron overload) patients worsens disease severity due to the synergistic effects of excess iron and alcohol.

Alcohol Contribution to Total Energy Intake and Its Association with Nutritional Status and Diet Quality in Eight Latina American Countries

Alcohol consumption is a modifiable risk factor for non-communicable diseases. This study aimed to characterize alcohol consumers at the nutritional, anthropometric, and sociodemographic levels. Data from 9218 participants from Argentina, Brazil, Chile, Colombia, Costa Rica, Ecuador, Peru, and Venezuela participating in “Latin American Health and Nutrition Study (ELANS)”, a multi-country, population-based study, were used. Dietary intake was collected through two, 24 h recalls. Participants were classified into consumers (n = 1073) and non-alcohol consumers (n = 8145) using a cut-off criterium of ≥15 g/day of alcohol consumption calculated from the estimation of their usual daily intake. Among alcohol consumers, the mean alcohol consumption was 69.22 ± 2.18 grams (4.6. beverages/day), contributing to 484.62 kcal, which corresponded to 16.86% of the total energy intake. We found that the risk of alcohol consumption was higher in young and middle-aged men from low and middle socioeconomic status. Argentine, Brazil, and Chile had the highest percentage of consumers, while Ecuador showed the highest alcohol consumption. Alcohol drinkers were characterized by having higher body weight and wider neck, waist, hips circumferences. Alcohol drinkers had a higher energy intake, with macronutrients providing relatively less energy at the expense of the energy derived from alcohol. Alcohol drinkers showed lower and higher consumptions of healthy and unhealthy food groups, respectively. In addition, adequacy ratios for all micronutrients assessed were lower in alcohol consumers. All these deleterious effects of alcohol on nutritional and anthropometric parameters increased with the number of alcoholic beverages consumed daily. Altogether, these findings suggest that limiting alcohol consumption can contribute to reducing the risk of obesity, metabolic syndrome, and diet-related diseases.

Clinical Characteristics and Survival Analysis in Frequent Alcohol Consumers With COVID-19

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection can generate a systemic disease named coronavirus disease-2019 (COVID-19). Currently, the COVID-19 pandemic has killed millions worldwide, presenting huge health and economic challenges worldwide. Several risk factors, such as age, co-infections, metabolic syndrome, and smoking have been associated with poor disease progression and outcomes. Alcohol drinking is a common social practice among adults, but frequent and/or excessive consumption can mitigate the anti-viral and anti-bacterial immune responses. Therefore, we investigated if patients with self-reported daily alcohol consumption (DAC) presented alteration in the immune response to SARS-CoV-2. We investigated 122 patients with COVID-19 (101 male and 46 females), in which 23 were patients with DAC (18 men and 5 women) and 99 were non-DAC patients (58 men and 41 women), without other infections, neoplasia, or immunodeficiencies. Although with no difference in age, patients with DAC presented an increase in severity-associated COVID-19 markers such as C-reactive protein (CRP), neutrophil count, and neutrophil-to-lymphocyte ratio. In addition, patients with DAC presented a reduction in the lymphocytes and monocytes counts. Importantly, the DAC group presented an increase in death rate in comparison with the non-DAC group. Our results demonstrated that, in our cohort, DAC enhanced COVID-19-associated inflammation, and increased the number of deaths due to COVID-19.

Review article: the role of nutrition in alcohol-associated liver disease

BACKGROUND

Malnutrition is a commonly encountered issue in patients with alcohol-associated liver disease. The role of nutritional supplementation in the management of alcohol-associated liver disease is integral to patient outcomes-it has been shown to decrease rates of hepatic encephalopathy, improve outcomes post-liver transplant, reduce 90-day hospital readmissions and lower mortality. Despite these benefits, many studies have shown nutritional support to be an underutilised tool in the care of patients with alcohol-associated liver disease.

AIMS

To review the epidemiology, pathophysiology, recommendations for nutritional assessment and supplementation, as well as future directions for research of the relationship between nutrition and alcohol-associated liver disease.

METHODS

A literature search was conducted via PubMed using MeSH terms to inform this narrative review.

RESULTS

Decreased dietary intake, socioeconomic status, impaired absorption of nutrients and increased free radical species are implicated in the pathophysiology of malnutrition in alcohol-associated liver disease.

CONCLUSIONS

Malnutrition is common in alcohol-associated liver disease, and physicians should be aware of its association with poor clinical outcomes. Routine nutritional assessment, involvement of a dietician and nutritional supplementation are recommended to improve clinical outcomes in patients with alcohol-associated liver disease.

Transcriptional analysis of the response of C. elegans to ethanol exposure

Ethanol-induced transcriptional changes underlie important physiological responses to ethanol that are likely to contribute to the addictive properties of the drug. We examined the transcriptional responses of Caenorhabditis elegans across a timecourse of ethanol exposure, between 30 min and 8 h, to determine what genes and genetic pathways are regulated in response to ethanol in this model. We found that short exposures to ethanol (up to 2 h) induced expression of metabolic enzymes involved in metabolizing ethanol and retinol, while longer exposure (8 h) had much more profound effects on the transcriptome. Several genes that are known to be involved in the physiological response to ethanol, including direct ethanol targets, were regulated at 8 h of exposure. This longer exposure to ethanol also resulted in the regulation of genes involved in cilia function, which is consistent with an important role for the effects of ethanol on cilia in the deleterious effects of chronic ethanol consumption in humans. Finally, we found that food deprivation for an 8-h period induced gene expression changes that were somewhat ameliorated by the presence of ethanol, supporting previous observations that worms can use ethanol as a calorie source.

Vitamin A Update: Forms, Sources, Kinetics, Detection, Function, Deficiency, Therapeutic Use and Toxicity

Vitamin A is a group of vital micronutrients widely present in the human diet. Animal-based products are a rich source of the retinyl ester form of the vitamin, while vegetables and fruits contain carotenoids, most of which are provitamin A. Vitamin A plays a key role in the correct functioning of multiple physiological functions. The human organism can metabolize natural forms of vitamin A and provitamin A into biologically active forms (retinol, retinal, retinoic acid), which interact with multiple molecular targets, including nuclear receptors, opsin in the retina and, according to the latest research, also some enzymes. In this review, we aim to provide a complex view on the present knowledge about vitamin A ranging from its sources through its physiological functions to consequences of its deficiency and metabolic fate up to possible pharmacological administration and potential toxicity. Current analytical methods used for its detection in real samples are included as well.

Associations of persistent organic pollutants in human adipose tissue with retinoid levels and their relevance to the redox microenvironment

Humans are exposed to a myriad of chemical substances in both occupational and environmental settings. Persistent organic pollutants (POPs) have drawn attention for their adverse effects including cancer and endocrine disruption. Herein, the objectives were 1) to describe serum and adipose tissue retinol levels, along with serum retinol binding protein 4 (RBP4) concentrations, and 2) to assess the associations of adipose tissue POP levels with these retinoid parameters, as well as their potential interaction with the previously-observed POP-related disruption of redox microenvironment. Retinol was measured in both serum and adipose tissue along with RBP4 levels in serum samples of 236 participants of the GraMo adult cohort. Associations were explored by multivariable linear regression analyses and Weighted Quantile Sum regression. Polychlorinated biphenyls (PCBs) 180, 153 and 138 were related to decreased adipose tissue retinol levels and increased serum RBP4/retinol ratio. Dicofol concentrations > limit of detection were associated with decreased retinol levels in serum and adipose tissue. Additionally, increased adipose tissue retinol levels were linked to an attenuation in previously-reported associations of adipose tissue PCB-153 with in situ superoxide dismutase activity. Our results revealed a suggestive link between retinoids, PCBs and redox microenvironment, potentially relevant for both mechanistic and public health purposes.

"Structural imprinting" of the cutaneous immune effector function

Keratinization provides tolerance to desiccation and mechanical durability. Loricrin, which is an epidermal thiol-rich protein, efficiently stabilizes terminally differentiated keratinocytes and maintains redox homeostasis. The discovery of the largely asymptomatic loricrin knockout (LKO) phenotype decades ago was rather unpredicted. Nevertheless, when including redox-driven, NF-E2-related factor 2-mediated backup responses, LKO mice provide opportunities for the observation of altered or "quasi-normal" homeostasis. Specifically, given that the tissue structure, as well as the local metabolism, transmits immunological signals, we sought to dissect the consequence of truncated epidermal differentiation program from immunological perspectives. Through a review of the aggregated evidence, we have attempted to generate an integrated view of the regulation of the peripheral immune system, which possibly occurs within the squamous epithelial tissue with truncated differentiation. This synthesis might not only provide insights into keratinization but also lead to the identification of factors intrinsic to the epidermis that imprint the immune effector function.

A Perspective Of Intestinal Immune-Microbiome Interactions In Alcohol-Associated Liver Disease

Uncovering the intricacies of the gut microbiome and how it interacts with the host immune system has opened up pathways in the search for the treatment of disease conditions. Alcohol-associated liver disease is a major cause of death worldwide. Research has shed light on the breakdown of the protective gut barriers, translocation of gut microbes to the liver and inflammatory immune response to microbes all contributing to alcohol-associated liver disease. This knowledge has opened up avenues for alternative therapies to alleviate alcohol-associated liver disease based on the interaction of the commensal gut microbiome as a key player in the regulation of the immune response. This review describes the relevance of the intestinal immune system, the gut microbiota, and specialized and non-specialized intestinal cells in the regulation of intestinal homeostasis. It also reflects how these components are altered during alcohol-associated liver disease and discusses new approaches for potential future therapies in alcohol-associated liver disease.

Multifactorial Genetic and Environmental Hedgehog Pathway Disruption Sensitizes Embryos to Alcohol-Induced Craniofacial Defects

BACKGROUND

Prenatal alcohol exposure (PAE) is perhaps the most common environmental cause of human birth defects. These exposures cause a range of structural and neurological defects, including facial dysmorphologies, collectively known as fetal alcohol spectrum disorders (FASD). While PAE causes FASD, phenotypic outcomes vary widely. It is thought that multifactorial genetic and environmental interactions modify the effects of PAE. However, little is known of the nature of these modifiers. Disruption of the Hedgehog (Hh) signaling pathway has been suggested as a modifier of ethanol teratogenicity. In addition to regulating the morphogenesis of craniofacial tissues commonly disrupted in FASD, a core member of the Hh pathway, Smoothened, is susceptible to modulation by structurally diverse chemicals. These include environmentally prevalent teratogens like piperonyl butoxide (PBO), a synergist found in thousands of pesticide formulations.

METHODS

Here, we characterize multifactorial genetic and environmental interactions using a zebrafish model of craniofacial development.

RESULTS

We show that loss of a single allele of shha sensitized embryos to both alcohol- and PBO-induced facial defects. Co-exposure of PBO and alcohol synergized to cause more frequent and severe defects. The effects of this co-exposure were even more profound in the genetically susceptible shha heterozygotes.

CONCLUSIONS

Together, these findings shed light on the multifactorial basis of alcohol-induced craniofacial defects. In addition to further implicating genetic disruption of the Hh pathway in alcohol teratogenicity, our findings suggest that co-exposure to environmental chemicals that perturb Hh signaling may be important variables in FASD and related craniofacial disorders.

Contribution of Behavioral Health Factors to Non-AIDS-Related Comorbidities: an Updated Review

PURPOSE OF REVIEW

We summarize recent literature on the contribution of substance use and depression to non-AIDS-related comorbidities. Discussion of recent randomized clinical trials and implementation research to curtail risk attributed to each behavioral health issue is provided.

RECENT FINDINGS

Smoking, unhealthy alcohol use, opioid use, and depression are common among PWH and individually contribute to increased risk for non-AIDS-related comorbidities. The concurrence of these conditions is notable, yet understudied, and provides opportunity for linked-screening and potential treatment of more than one behavioral health factor. Current results from randomized clinical trials are inconsistent. Investigating interventions to reduce the impact of these behavioral health conditions with a focus on implementation into clinical care is important. Non-AIDS-defining cancers, cardiovascular disease, liver disease, and diabetes are leading causes of morbidity in people with HIV. Behavioral health factors including substance use and mental health issues, often co-occurring, likely contribute to the excess risk of non-AIDS-related comorbidities.

Mediterranean diet, alcohol-drinking pattern and their combined effect on all-cause mortality: the Seguimiento Universidad de Navarra (SUN) cohort

PURPOSE

The health benefits of the Mediterranean diet (MedDiet) have been widely studied. However, controversy remains for one of its components: alcohol intake. We aimed to assess the joint effect of adherence to the MedDiet and alcohol-drinking pattern on all-cause mortality.

METHODS

We used data from 20,506 subjects from a prospective cohort of Spanish university graduates, the Seguimiento Universidad de Navarra (SUN) cohort. Adherence to the MedDiet was operationalized using four different dietary indexes and then categorized in low or high adherence, according to the median score. Alcohol-drinking pattern was evaluated with the previously defined the Mediterranean alcohol-drinking pattern (MADP), grouped into three categories of adherence (low, moderate and high adherence) and a fourth category for abstainers. The outcome was all-cause mortality.

RESULTS

During a median follow-up of 12.1 years, we observed 460 deaths. No statistically significant supra-multiplicative interaction between the two exposures was found. Low adherence to both the MedDiet and MADP was associated with higher all-cause mortality compared to high adherence to both exposures [multivariable-adjusted hazard ratio (HR) = 2.02, 95% confidence interval (CI): 1.33-3.07]. Similar results were found for cancer mortality and cardiovascular mortality.

CONCLUSIONS

Although the combined effect of the MedDiet and MADP was not significantly higher than the product of their individual effects, a low adherence to both the MedDiet and MADP was associated with higher rates of all-cause mortality. This report also shows the usefulness of the dietary pattern approach applied to alcohol intake and of including the drinking pattern as another component of the MedDiet.

Hormonal responses in gambling versus alcohol abuse: A review of human studies

The endocrine system plays an essential role in communication between various organs of the body to maintain homeostasis. Both substance use disorders (SUDs) and non-substance abuse disrupt this system and lead to hormonal dysregulations. Here, we focus on the comparison between the function of the endocrine system in gambling disorders and alcohol addiction to understand the commonalities and differences in their neurobiological and psychological underpinnings. We review human research to compare findings on gambling addiction and alcohol dependence pertaining to the dynamic interplay between testosterone and cortisol. Understanding and classifying similarities in hormonal responses between behavioural addiction and SUDs may facilitate development of treatments and therapeutic interventions across different types of addictive disorders, while describing differences may shed light on therapeutic interventions for specific disorders. Although research on gambling addiction is in its infancy, such evaluation may still have a positive effect for addiction research, thereby stimulating discovery of "crossover" pharmacotherapies with benefits for both SUDs and nonsubstance addictions.

Alcoholism and nutrition: a review of vitamin supplementation and treatment

PURPOSE OF REVIEW

This is a review of the research on the effectiveness of vitamin supplementation for alcoholism and alcohol-related illnesses. The focus is on research, both clinical and basic on alcohol treatment and nutritional effectiveness of these vital nutrients.

RECENT FINDINGS

Most of the research involves basic experiments exploring the impact of vitamin depletion or deficits on physiological systems, especially liver and brain, in rodents. These often include behavioral measures that use cognitive, learning/memory and motivation experiments that model clinical studies. These provide support for hypotheses concerning the impact of such deficiencies in clinical populations. Clinical studies are rare and involve evaluation of the outcome of supplementation usually in the context of a treatment program. Specific vitamins, dosages and treatment programs vary. Deficiencies in retinoids (vitamin A), thiamine (B1) and niacin (B3) are the most frequently investigated. However, there is a greater need for further research on other vitamins, and for more uniform supplementation and treatment procedures.

SUMMARY

The literature is primarily basic research on specific vitamins. There are very significant findings with individual vitamin supplementation and combinations that show promise of our understanding of the role of vitamins in the disease of alcoholism and its treatment.

Carotenoids and fatty liver disease: Current knowledge and research gaps

Carotenoids form an important part of the human diet, consumption of which has been associated with many health benefits. With the growing global burden of liver disease, increasing attention has been paid on the possible beneficial role that carotenoids may play in the liver. This review focuses on carotenoid actions in non-alcoholic fatty liver disease (NAFLD), and alcoholic liver disease (ALD). Indeed, many human studies have suggested an association between decreased circulating levels of carotenoids and increased incidence of NAFLD and ALD. The literature describing supplementation of individual carotenoids in rodent models of NAFLD and ALD is reviewed, with particular attention paid to β-carotene and lycopene, but also including β-cryptoxanthin, lutein, zeaxanthin, and astaxanthin. The effect of beta-carotene oxygenase 1 and 2 knock-out mice on hepatic lipid metabolism is also discussed. In general, there is evidence to suggest that carotenoids have beneficial effects in animal models of both NAFLD and ALD. Mechanistically, these benefits may occur via three possible modes of action: 1) improved hepatic antioxidative status broadly attributed to carotenoids in general, 2) the generation of vitamin A from β-carotene and β-cryptoxanthin, leading to improved hepatic retinoid signaling, and 3) the generation of apocarotenoid metabolites from β-carotene and lycopene, that may regulate hepatic signaling pathways. Gaps in our knowledge regarding carotenoid mechanisms of action in the liver are highlighted throughout, and the review ends by emphasizing the importance of dose effects, mode of delivery, and mechanism of action as important areas for further study. This article is part of a Special Issue entitled Carotenoids recent advances in cell and molecular biology edited by Johannes von Lintig and Loredana Quadro.

Regulation of Hepatitis C Virus Infection by Cellular Retinoic Acid Binding Proteins through the Modulation of Lipid Droplet Abundance

Retinoid (vitamin A) is an essential diet constituent that governs a broad range of biological processes. Its biologically active metabolite, all-trans retinoic acid (ATRA), exhibits a potent antiviral property by enhancing both innate and adaptive antiviral immunity against a variety of viral pathogens, such as, but not limited to, HIV, respiratory syncytial virus (RSV), herpes simplex virus (HSV), and measles. Even though the hepatocyte is highly enriched with retinoid and its metabolite ATRA, it supports the establishment of efficient hepatitis C virus (HCV) replication. Here, we demonstrate the hepatocyte-specific cell-intrinsic mechanism by which ATRA exerts either a proviral or antiviral effect, depending on how it engages cellular retinoic acid binding proteins (CRABPs). We found that the engagement of CRABP1 by ATRA potently supported viral infection by promoting the accumulation of lipid droplets (LDs), which robustly enhanced the formation of a replication complex on the LD-associated endoplasmic reticulum (ER) membrane. In contrast, ATRA binding to CRABP2 potently inhibited HCV via suppression of LD accumulation. However, this antiviral effect of CRABP2 was abrogated due to the functional and quantitative predominance of CRABP1 in the hepatocytes. In summary, our study demonstrates that CRABPs serve as an on-off switch that modulates the efficiency of the HCV life cycle and elucidates how HCV evades the antiviral properties of ATRA via the exploitation of CRABP1 functionality.IMPORTANCE ATRA, a biologically active metabolite of vitamin A, exerts pleiotropic biological effects, including the activation of both innate and adaptive immunity, thereby serving as a potent antimicrobial compound against numerous viral pathogens. Despite the enrichment of hepatocytes with vitamin A, HCV still establishes an efficient viral life cycle. Here, we discovered that the hepatocellular response to ATRA creates either a proviral or an antiviral environment depending on its engagement with CRABP1 or -2, respectively. CRABP1 supports the robust replication of HCV, while CRABP2 potently inhibits the efficiency of viral replication. Our biochemical, genetic, and microscopic analyses reveal that the pro- and antiviral effects of CRABPs are mediated by modulation of LD abundance, where HCV establishes the platform for viral replication and assembly on the LD-associated ER membrane. This study uncovered a cell-intrinsic mechanism by which HCV exploits the proviral function of CRABP1 to establish an efficient viral life cycle.

The Hepatic Lipidome: A Gateway to Understanding the Pathogenes is of Alcohol-Induced Fatty Liver

Chronic alcohol consumption can lead to the development of alcoholic fatty liver disease. The underlying pathogenic mechanisms however, have not been fully elucidated. Here, we review the current state of the art regarding the application of lipidomics to study alcohol's effect on hepatic lipids. It is clear that alcohol has a profound effect on the hepatic lipidome, with documented changes in the major lipid categories (i.e. fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, sterol lipids and prenol lipids). Alcohol's most striking effect is the marked change in the hepatic fatty acyl pool. This effect includes increased levels of 18-carbon fatty acyl chains incorporated into multiple lipid species, as well as a general shift toward increased unsaturation of fatty acyl moieties. In addition to our literature review, we also make several recommendations to consider when designing lipidomic studies into alcohol's effects. These recommendations include integration of lipidomic data with other measures of lipid metabolism, inclusion of multiple experimental time points, and presentation of quantitative data. We believe rigorous analysis of the hepatic lipidome can yield new insight into the pathogenesis of alcohol-induced fatty liver. While the existing literature has been largely descriptive, the field is poised to apply lipidomics to yield a new level of understanding on alcohol's effects on hepatic lipid metabolism.

Nutrition in Alcoholic Liver Disease: An Update

Malnutrition is a change in body composition owing to disordered nutrition associated with a decrease in function and poor clinical outcomes. Malnutrition can result from overnutrition, undernutrition and inflammatory activity. Patients with alcoholic liver disease are at increased risk for malnutrition. In this article, we discuss the different methods used to assess malnutrition, prevalence of malnutrition, potential mechanisms underlying malnutrition, and its treatments in patients with alcoholic liver disease.

An Argument for Vitamin D, A, and Zinc Monitoring in Cirrhosis

Malnutrition is prevalent in cirrhosis. Vitamin and mineral deficiencies, including vitamin D, vitamin A, and zinc, are common and have been shown to correlate with survival. Our aim was to review the mechanisms of vitamin D, vitamin A, and zinc deficiencies in cirrhosis and the clinical assessment of affected patients, their outcomes based on the current literature, and management. This is a narrative review including the relevant literature for cirrhosis and vitamin D, vitamin A, and zinc deficiencies. Vitamin D deficiency has important effects in cirrhosis, regardless of the cause of chronic liver disease.These effects include associations with fibrosis and outcomes such as infections, hepatocellular carcinoma, and mortality. Vitamin A deficiency is associated with liver disease progression to cirrhosis and clinical decompensation, including occurrence of ascites or hepatic encephalopathy. Zinc deficiency can lead to hepatic encephalopathy and impaired immune function. Such deficiencies correlate with patient survival and disease severity. Caution should be applied when replacing vitamin D, vitamin A, and zinc to avoid toxicity. Identification and appropriate treatment of vitamin and mineral deficiencies in cirrhosis may reduce specific nutritional and cirrhosis-related adverse events. Routine monitoring of vitamin A, vitamin D and zinc levels in cirrhosis should be considered.

Retinoic acid signaling is essential for airway smooth muscle homeostasis

Airway smooth muscle (ASM) is a dynamic and complex tissue involved in regulation of bronchomotor tone, but the molecular events essential for the maintenance of ASM homeostasis are not well understood. Observational and genome-wide association studies in humans have linked airway function to the nutritional status of vitamin A and its bioactive metabolite retinoic acid (RA). Here, we provide evidence that ongoing RA signaling is critical for the regulation of adult ASM phenotype. By using dietary, pharmacologic, and genetic models in mice and humans, we show that (a) RA signaling is active in adult ASM in the normal lung, (b) RA-deficient ASM cells are hypertrophic, hypercontractile, profibrotic, but not hyperproliferative, (c) TGF-β signaling, known to cause ASM hypertrophy and airway fibrosis in human obstructive lung diseases, is hyperactivated in RA-deficient ASM, (d) pharmacologic and genetic inhibition of the TGF-β activity in ASM prevents the development of the aberrant phenotype induced by RA deficiency, and (e) the consequences of transient RA deficiency in ASM are long-lasting. These results indicate that RA signaling actively maintains adult ASM homeostasis, and disruption of RA signaling leads to aberrant ASM phenotypes similar to those seen in human chronic airway diseases such as asthma.

Supplementation of all trans retinoic acid ameliorates ethanol-induced endoplasmic reticulum stress

CONTEXT

Molecular pathogenesis of chronic alcoholism is linked to increased endoplasmic reticulum stress. Ethanol is a competitive inhibitor of vitamin A metabolism and vitamin A supplementation aggravates existing liver problems. Hence, we probed into the impact of supplementation of all trans retinoic acid (ATRA), the active metabolite of vitamin A on ethanol-induced endoplasmic reticulcum stress.

METHODS

Male Sprague-Dawley rats were divided into four groups - I: Control; II: Ethanol; III: ATRA; IV: ATRA + Ethanol. After 90 days the animals were sacrificed to study markers of lipid peroxidation in hepatic microsomal fraction and expression of ER stress proteins and apoptosis in liver.

RESULTS AND CONCLUSION

Ethanol caused hepatic hyperlipidemia, enhanced microsomal lipid peroxidation, upregulated expression of unfolded protein response associated proteins and that of apoptosis. Ethanol also led to downregulation of retinoid receptors. ATRA supplementation reversed all these alterations indicating the decrease in ethanol-induced endoplasmic reticulum stress.

Competition between ethanol clearance and retinoic acid biosynthesis in the induction of fetal alcohol syndrome

Several models have been proposed to explain the neurodevelopmental syndrome induced by exposure of human embryos to alcohol, which is known as fetal alcohol spectrum disorder (FASD). One of the proposed models suggests a competition for the enzymes required for the biosynthesis of retinoic acid. The outcome of such competition is development under conditions of reduced retinoic acid signaling. Retinoic acid is one of the biologically active metabolites of vitamin A (retinol), and regulates numerous embryonic and differentiation processes. The developmental malformations characteristic of FASD resemble those observed in vitamin A deficiency syndrome as well as from inhibition of retinoic acid biosynthesis or signaling in experimental models. There is extensive biochemical and enzymatic overlap between ethanol clearance and retinoic acid biosynthesis. Several lines of evidence suggest that in the embryo, the competition takes place between acetaldehyde and retinaldehyde for the aldehyde dehydrogenase activity available. In adults, this competition also extends to the alcohol dehydrogenase activity. Ethanol-induced developmental defects can be ameliorated by increasing the levels of retinol, retinaldehyde, or retinaldehyde dehydrogenase. Acetaldehyde inhibits the production of retinoic acid by retinaldehyde dehydrogenase, further supporting the competition model. All of the evidence supports the reduction of retinoic acid signaling as the etiological trigger in the induction of FASD.

Role of A-Kinase Anchoring Protein Phosphorylation in Alcohol-Induced Liver Injury and Hepatic Stellate Cell Activation

Alcoholic liver injury is associated with hepatic stellate cell (HSC) activation. A-kinase anchoring protein 12 (AKAP12) scaffolds protein kinase C and cyclin-D1, which is regulated by its phosphorylation, and spatiotemporally controls cell proliferation, invasiveness, and chemotaxis. HSC activation induces AKAP12 expression, but the role of AKAP12's scaffolding activity in liver function is unknown. Because AKAP12 phosphorylation is enhanced in ethanol-treated HSCs, we examined AKAP12's scaffolding functions in alcohol-mediated HSC activation and liver injury. AKAP12 expression, interaction, and phosphorylation were assayed in in vitro and in vivo ethanol models and human subjects by real-time PCR, coimmunoprecipitation, immunoblotting, and phosphorylated proteomics/Phos-tag. Ethanol induced AKAP12 phosphorylation in the liver and in primary HSCs, but not in hepatocytes. AKAP12's scaffolding activity for protein kinase C/cyclin-D1 decreased in ethanol-treated HSCs but not hepatocytes. AKAP12 negatively regulated HSC activation, which was reversed by ethanol-mediated AKAP12 phosphorylation. AKAP12 interacted with heat shock protein 47 (HSP47), which chaperones collagen and induces its secretion. Ethanol inhibited AKAP12-HSP47 and induced HSP47-collagen interaction. Ethanol-induced phosphorylated AKAP12 was unable to bind to HSP47 compared with its unphosphorylated counterpart, thereby proving that ethanol-mediated phosphorylation of AKAP12 inhibited the HSP47-AKAP12 scaffold. Silencing AKAP12 facilitated the chaperoning of collagen by HSP47. Hence, AKAP12 scaffolds HSP47 and regulates collagen-HSP47 interaction. Ethanol quenches AKAP12's scaffolding activity through phosphorylation and facilitates HSC activation.

Alcohol intake aggravates adipose browning and muscle atrophy in cancer-associated cachexia

Cancer is commonly associated with cachexia, a paraneoplastic syndrome characterized by body weight loss, muscle wasting, adipose tissue atrophy and inflammation. Chronic alcohol consumption increases the risk of multiple types of cancer, and enhances cancer-associated cachexia (CAC), but the underlying mechanisms remain poorly defined. To test, C57BL/6 mice were fed with 0% or 20% (w/v) alcohol for 3 months, then inoculated with B16BL6 melanoma cells subcutaneously in the right side of the hip and continued to feed with/without alcohol for 3 or 4 weeks. Alcohol intake upregulated ALDH1A1 expression and elevated retinoic acid (RA) content in inguinal white adipose tissue (iWAT), which led to enhanced iWAT browning and brown adipose tissue (BAT) activation, accelerating fat loss. Moreover, alcohol increased muscle loss through augmenting muscle protein degradation, cell apoptosis and inflammation. In addition, alcohol reduced satellite cell density and impaired myogenesis in skeletal muscle. Taken together, alcohol aggravates cancer-associated cachexia at least partially through elevating adipose browning and muscle atrophy.

Detrimental effects of alcohol exposure around conception: putative mechanisms

In western countries, alcohol consumption is widespread in women of reproductive age, and in binge quantities. These countries also continue to have high incidences of unplanned pregnancies, with women often reported to cease drinking after discovering their pregnancy. This suggests the early embryo may be highly exposed to the detrimental effects of alcohol during the periconception period. The periconception and pre-implantation windows, which include maturation of the oocyte, fertilisation, and morphogenesis of the pre-implantation embryo, are particularly sensitive times of development. Within the oviduct and uterus, the embryo is exposed to a unique nutritional environment to facilitate its development and establish de-novo expression of the genome through epigenetic reprogramming. Alcohol has wide-ranging effects on cellular stress, as well as hormonal, and nutrient signalling pathways, which may affect the development and metabolism of the early embryo. In this review, we summarise the adverse developmental outcomes of early exposure to alcohol (prior to implantation in animal models) and discuss the potential mechanisms for these outcomes that may occur within the protected oviductal and uterine environment. One interesting candidate is reduced retinoic acid synthesis, as it is implicated in the control of epigenetic reprogramming and cell lineage commitment, processes that have adverse consequences for the formation of the placenta, and subsequently, fetal programming.

The importance of nutrition in aiding recovery from substance use disorders: A review

BACKGROUND

Nutrition is a prerequisite for health; yet, there is no special nutritional assessment or guidance for drug and alcohol dependent individuals, despite the fact that their food consumption is often very limited, risking malnutrition. Further, the premise is examined that malnutrition may promote drug seeking and impede recovery from substance use disorders (SUD).

METHOD

A narrative review addressed the relationship between substance use disorders and nutrition, including evidence for malnutrition, as well as their impact on metabolism and appetite regulation. The implications of the biopsychology of addiction and appetite for understanding the role of nutrition in SUD were also considered.

RESULTS

The literature overwhelmingly finds that subjects with alcohol use disorder (AUD) and drug use disorder (DUD) typically suffer from nutrient deficiencies. These nutrient deficiencies may be complicit in the alcoholic myopathy, osteopenia and osteoporosis, and mood disorders including anxiety and depression, observed in AUD and DUD. These same individuals have also been found to have altered body composition and altered hormonal metabolic regulators. Additionally, brain processes fundamental for survival are stimulated both by food, particularly sweet foods, and by substances of abuse, with evidence supporting confusion (addiction transfer) when recovering from SUD between cravings for a substance and craving for food.

CONCLUSION

Poor nutritional status in AUD and DUD severely impacts their physical and psychological health, which may impede their ability to resist substances of abuse and recover their health. This review contributes to a better understanding of interventions that could best support individuals with substance use disorders.

Alcohol and Hepatocellular Carcinoma: Adding Fuel to the Flame

Primary tumors of the liver represent the fifth most common type of cancer in the world and the third leading cause of cancer-related death. Case-control studies from different countries report that chronic ethanol consumption is associated with an approximately 2-fold increased odds ratio for hepatocellular carcinoma (HCC). Despite the substantial epidemiologic data in humans demonstrating that chronic alcohol consumption is a major risk factor for HCC development, the pathways causing alcohol-induced liver cancer are poorly understood. In this overview, we summarize the epidemiological evidence for the association between alcohol and liver cancer, review the genetic, oncogenic, and epigenetic factors that drive HCC development synergistically with ethanol intake and discuss the essential molecular and metabolic pathways involved in alcohol-induced liver tumorigenesis.

Loss of control over the ethanol consumption: differential transcriptional regulation in prefrontal cortex

Alcohol use disorder (AUD) is a complex multifactorial disease with heritability of ∼50% and corresponds to the state in which the body triggers a reinforcement or reward compulsive behavior due to ethanol consumption, even when faced with negative consequences. Although several studies have shown the impact of high ethanol intake on the prefrontal cortex (PFC) gene expression, few have addressed the relationship between the patterns of gene expression underlying the compulsive behaviour associated with relapsing. In this study, we used a chronic three-bottle free-choice mouse model to investigate the PFC transcriptome in three different groups of mice drinkers: 'Light drinkers' (preference for water throughout the experiment); 'Heavy drinkers' (preference for ethanol with a non-compulsive intake), and 'Inflexible drinkers' (preference for ethanol with a compulsive drinking component). Our aim was to correlate the intake patterns observed in this model with gene expression changes in the PFC, a brain region critical for the development and maintenance of alcohol addiction. We found that the Camk2a gene showed a downregulated profile only in the Inflexible when compared to the Light drinkers group, the Camk2n1 and Pkp2 genes showed an upregulated profile only in the Inflexible drinkers when compared to the Control group, and the Gja1 gene showed an upregulated profile in the Light and Inflexible drinkers when compared to the Control group. These different transcription patterns have been associated to the presence of alcohol, in the Camk2n1 and Gja1 genes; to the amount of ethanol consumed, in the Camk2a gene; and to the loss of control in the alcohol consumption, in the Pkp2 gene. Here, we provide, for the first time, the potential involvement of the Pkp2 gene in the compulsivity and loss of control over the voluntary ethanol consumption.

Moderate alcohol intake induces thermogenic brown/beige adipocyte formation via elevating retinoic acid signaling

Clinically, low and moderate alcohol intake improves human health with protection against metabolic syndromes, including type 2 diabetes; however, mechanisms that are associated with these effects remain to be elucidated. The aims of this study were to investigate the effects of moderate alcohol intake on thermogenic brown/beige adipocyte formation and glucose and lipid homeostasis, as well as the involvement of retinoic acid (RA) signaling in the entire process. C57BL6 male mice were supplemented with 8% (w/v) alcohol in water for 1 or 4 mo. Alcohol intake prevented body weight gain, induced the formation of uncoupling protein 1-positive beige adipocytes in white adipose tissue, and increased thermogenesis in mice, which is associated with decreased serum glucose and triacylglycerol levels. Mechanistically, alcohol intake increased RA levels in serum and adipose tissue, which was associated with increased expression of aldehyde dehydrogenase family 1 subfamily A1 (Aldh1a1). When RA receptor-α signaling was conditionally blocked in platelet-derived growth factor receptor-α-positive adipose progenitors, the effects of alcohol on beige adipogenesis were largely abolished. Finally, moderate alcohol prevented high-fat diet-induced obesity and metabolic dysfunction. In conclusion, moderate alcohol intake induces thermogenic brown/beige adipocyte formation and promotes glucose and lipid oxidation via elevation of RA signaling.-Wang, B., Wang, Z., de Avila, J. M., Zhu, M.-J., Zhang, F., Gomez, N. A., Zhao, L., Tian, Q., Zhao, J., Maricelli, J., Zhang, H., Rodgers, B. D., Du, M. Moderate alcohol intake induces thermogenic brown/beige adipocyte formation via elevating retinoic acid signaling.