Herp mRNA expression in patients classified according to Lesch's typology

The Molecular Basis of Alcohol Use Disorder (AUD). Genetics, Epigenetics, and Nutrition in AUD: An Amazing Triangle

Alcohol use disorder (AUD) is a very common and complex disease, as alcohol is the most widely used addictive drug in the world. This disorder has an enormous impact on public health and social and private life, and it generates a huge number of social costs. Alcohol use stimulates hypothalamic-pituitary-adrenal (HPA) axis responses and is the cause of many physical and social problems (especially liver disease and cancer), accidental injury, and risky sexual behavior. For years, researchers have been trying to identify the genetic basis of alcohol use disorder, the molecular mechanisms responsible for its development, and an effective form of therapy. Genetic and environmental factors are known to contribute to the development of AUD, and the expression of genes is a complicated process that depends on epigenetic modulations. Dietary nutrients, such as vitamins, may serve as one these modulators, as they have a direct impact on epigenomes. In this review, we connect gathered knowledge from three emerging fields-genetics, epigenetics, and nutrition-to form an amazing triangle relating to alcohol use disorder.

Emerging Role of Epigenetic Mechanisms in Alcohol Addiction

Alcohol use disorder (AUD) is a complex brain disorder with an array of persistent behavioral and neurochemical manifestations. Both genetic and environmental factors are known to contribute to the development of AUD, and recent studies on alcohol exposure and subsequent changes in gene expression suggest the importance of epigenetic mechanisms. In particular, histone modifications and DNA methylation have emerged as important regulators of gene expression and associated phenotypes of AUD. Given the therapeutic potential of epigenetic targets, this review aims to summarize the role of epigenetic regulation in our current understanding of AUD by evaluating known epigenetic signatures of brain regions critical to addictive behaviors in both animal and human studies throughout various stages of AUD. More specifically, the effects of acute and chronic alcohol exposure, tolerance, and postexposure withdrawal on epigenetically induced changes to gene expression and synaptic plasticity within key brain regions and the associated behavioral phenotypes have been discussed. Understanding the contribution of epigenetic regulation to crucial signaling pathways may prove vital for future development of novel biomarkers and treatment agents in ameliorating or preventing AUD.

Non-right-handedness and free serum testosterone levels in detoxified patients with alcohol dependence

AIMS

The influence of testosterone on the extent of hemispheric dominance has been discussed not just during the first two trimesters of pregnancy but also later in life. An increase in free serum testosterone levels has been found during and after the detoxification phase of patients with alcohol dependence.

METHODS

In 250 participants (125 men and 125 women) with alcohol dependence immediately after the direct withdrawal phase (Day 21) and in 250 healthy age- and gender-matched participants, free testosterone in the serum was determined and handedness was assessed as a peripheral marker of central hemispheric dominance.

RESULTS

Patients with alcohol dependence were 2.7-fold (odds ratio, OR: 2.66; 95% confidence interval, CI: 1.62-4.38) and men 4.1-fold (OR: 4.12; 95% CI: 2.44-6.98) more likely to be non-right-handed (NRH). In addition to male gender, non-right-handedness and alcohol dependence contributed statistically significantly to higher serum testosterone levels. Testosterone values of patients with alcohol dependence differed significantly between the four different Lesch subtypes; in particular, participants with alcohol dependence classified according to Lesch subtype IV were found to have significantly higher serum testosterone levels (F = 20.5; P < 0.001) when compared to participants classified according to Lesch subtypes I-III.

CONCLUSIONS

An alteration of hemispheric dominance and thus an exogenously modifiable neuronal plasticity may be demonstrated directly on a population at risk.