Genetics research has offered important contributions to the understanding of how gene variations, or differences in a person’s genes, influence his or her susceptibility for developing certain types of disease. For example, having an alcoholic parent can increase the risk of developing alcohol use problems by three to four times. As alcohol and other drug abuse tends to run in families, 40 to 60 percent of children of alcoholic parents will end up with alcohol and drug use problems themselves. However, a growing body of evidence suggests that genetic factors are not fully responsible for our vulnerability to alcoholism and other types of disease.
Recent epigenetics research has shown that the risk for alcoholism and other types of disease is also profoundly influenced by the exposure to environmental factors including chronic stress, certain lifestyle behaviors and environmental toxins. Researchers argue that epigenetic factors can change the way that a gene is expressed without making changes to the DNA itself; such epigenetic factors can therefore increase the vulnerability for alcoholism and influence phenotype expression by changing the expression of genes.
Types of epigenetic changes
Chemical changes can occur within DNA nucleotides and alter the instructional messages passed on by genes. Epigenetic changes can affect the histone, which are proteins that bind to DNA to form chromatin (a complex of DNA and proteins that makes up chromosomes), or the DNA via histone modifications or DNA methylation mechanisms, respectively. Two primary chemical modifications can occur to histones; a methyl group can be added to the DNA (called methylation) or an acetyl group can be added to the DNA (called acetylation), both types of modifications can occur as part of normal development, but they can also lead to silencing or activating gene expression.
Study finds that trichostatin A may be beneficial for alcoholism-related anxiety
A recent study conducted by Subhash C. Pandey, Ph.D., professor of psychiatry and director of the Center for Alcohol Research in Epigenetics at the University of Illinois at Chicago in Illinois, and his colleagues, investigated histone modifications that occur due to alcohol exposure during adolescence and the impact of adolescent alcohol exposure on the development of alcoholism and anxiety in adulthood. The results of this study indicated that rats exposed to alcohol during adolescence had increased anxiety-like and alcohol drinking behaviors in adulthood.
Pandey and colleagues’ study found evidence for the lasting changes that occur in the amygdala, an important brain structure that is implicated in alcohol drinking and anxiety-like behaviors. In particular, the researchers also found that the rats that had been exposed to alcohol during adolescence had diminished expression of two genes: brain-derived neurotrophic factor (BDNF) and activity-regulated cytoskeleton-associated histone modifications in the amygdala. This study provided evidence for the long-lasting changes produced by adolescent alcohol use and the epigenetic changes that occurred as a result of alcohol exposure.
Pandey and colleagues then examined the effects of trichostatin A (TSA) treatment on gene-specific histone acetylation and the anxiety-like behaviors and alcohol intake of rats. TSA is an antifungal antibiotic drug that inhibits histone deacetylase (HDAC), which is over-expressed in people who have cancer. In the study, alcohol exposure during adolescence increased HDAC activity and respective changes in the amygdala during adolescence. By treating rats with TSA, the researchers significantly reduced the alcohol intake and anxiety-like behavior of rats, which suggested that this drug may be beneficial for treating anxiety-like and alcohol intake behaviors through the normalization of histone changes in the amygdala caused by early alcohol exposure. The researchers will examine TSA treatment and other epigenetic drugs to combat the harmful consequences of alcohol exposure during adolescence in future studies.
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About the author
Amanda Habermann is a staff writer for Sovereign Health. A graduate of California Lutheran University, she received her M.S. in clinical psychology with an emphasis in psychiatric rehabilitation. Her master’s thesis was written on “The effect of parental codependency on elementary school children’s social and emotional development,” and her research has been accepted for poster presentations at the Western Psychological Association. She brings to the team her extensive clinical background and skills in psychological testing and assessment, clinical diagnosis, research and treatment and recovery techniques for patients with mental illness. She is a passionate researcher and enjoys staying up to date on the newest topics in the field. For more information and other inquiries about this article, contact the author at firstname.lastname@example.org.