Epigenetics is the study of DNA modifications that change the gene expression but do not affect the underlying DNA sequence. Epigenetic modifications are natural occurrences that are influenced by factors like heredity, age, diet, lifestyle, environment, exposure to pollutants, and the person's medical condition. The three common types of epigenetic modifications are DNA methylation, non-coding RNA-associated gene silencing, and histone modification. While the previous research on this topic dealt with the relationship between epigenetics and the immune system, the present research covers new knowledge on the subject of epigenetics that has been unearthed by researchers in recent years. New studies on the subject of epigenetics have found that drinking coffee and tea can boost epigenetic health, divergent epigenetic patterns cause human brain hemispheric asymmetry, epigenetic changes can cause liver diseases, adolescent exposure to cannabis impacts the epigenetic response to cocaine, and space travel affects gene expression and causes cognitive dysfunction. These findings are presented below in detail.
Drinking Coffee and Tea Can Boost Epigenetic Health
- Preliminary research done by Mohsen Ghanbari and his colleagues at the Erasmus University Medical Center in Rotterdam, the Netherlands, has shown that coffee and tea consumption produces certain epigenetic modifications in the human body that lead to a host of health benefits.
- The study evaluated the coffee and tea consumption patterns of 15,789 people of European and African-American ancestries from 15 separate epigenetic studies. The researchers searched for specific epigenetic markers and found a direct correlation between the consumption of coffee and tea and reduced risk of certain diseases, especially heart and liver diseases.
- The research has shown that coffee and tea consumption is potentially linked with lower blood sugar, a sharper memory, enhanced liver health, protection against the development of dementia, and even longer lifespan. Coffee and tea have caffeine and other compounds that boost the mood and physical activity in humans.
- The research has shown that coffee and tea produce epigenetic modifications through differential DNA methylation.
- However, this was not the first research study that established the benefits of coffee and tea consumption. Earlier research had shown that coffee can reinforce DNA strands against breakage and even repair broken DNA strands through the process of DNA methylation. This can potentially affect gene expression related to Type 2 diabetes, Alzheimer's disease, and Parkinson's disease.
Divergent Epigenetic Patterns Cause Human Brain Hemispheric Asymmetry
- A study conducted by Dr. Viviane Labrie and her colleagues at the Van Andel Institute, Michigan, has shown that epigenetic regulation is responsible for the hemispheric asymmetry in the human brain.
- The study has uncovered one of the biggest mysteries in neuroscience: why people are differentiated as being either left-brained or right-brained. The researchers found that certain genes on either side of the brain are alternately switched between "on" and "off" states through epigenetic regulation.
- To determine how hemispherical differences in DNA methylation affects neuron functions in the healthy brain and the brain affected by Parkinson's disease, the researchers mapped DNA methylation in neurons in 57 healthy individuals and 48 individuals suffering from Parkinson's disease. The team did not find any marked hemispherical asymmetry in the prefrontal cortices of the two subject groups. However, they found significant hemispherical asymmetry in DNA methylation in the cortical neurons in both subject groups.
- The researchers concluded that the hemispherical asymmetry between the two sides of the brain may lead to epigenetic abnormalities that make the brain vulnerable to neurological diseases like Parkinson's. The progress of the disease leads to more advanced symptoms of degeneration in one side of the body compared to the other.
- The findings allow scientists to investigate the symptom asymmetry in Parkinson's disease that affect immune function, brain cell development, and cellular communication. Dr. Labrie and her team have already started to research hemispherical asymmetry in other neurological diseases like Alzheimer's.
Epigenetic Changes Can Cause Liver Diseases
- A study conducted by Dr. Johanna K. DiStefano and her colleagues at the Translational Genomics Research Institute in Phoenix, Arizona, has shown that epigenetic modifications like altered DNA methylation can lead to liver diseases.
- Nonalcoholic fatty liver disease (NAFLD) or fatty liver affects almost 30% of the population of the United States. Almost 10% of the NAFLD patients experience severity in their condition leading to inflammation, fibrosis, and even cirrhosis or liver cancer.
- To proceed with the study, the team of researchers collected intraoperative liver wedge biopsies from Caucasian women and enrolled in the Geisinger Clinic Center for Nutrition and Weight Management. Then they compared the DNA methylation in these samples with samples from another control group with a history of obesity and liver cirrhosis problems. They wanted to determine the correlation of altered DNA methylation with liver diseases.
- The team found different patterns of DNA methylation in both sets, specifically related to the genes involved in reactive nitrogen and reactive oxygen species production, which immune cells produce during liver inflammation. Even the genes involved in lipid metabolism showed different results between the two study groups.
- The study proved that NAFLD alters the epigenetic regulation of gene expression. Cirrhosis is the advanced state of excessive epigenetic changes involved in lipid metabolism and liver inflammation.
Adolescent Exposure to Cannabis Impacts the Epigenetic Response to Cocaine
- A joint study on rodents by researchers at the University of Cagliari in Italy and Columbia University has shown that adolescent exposure to cannabis impacts the epigenetic response increasing the sensitivity of the brain to subsequent cocaine exposure.
- In the study, the researchers administered the synthetic psychoactive cannabinoid WIN to both adolescent and adult rats and monitored their brain functions. Then they administered cocaine to both sets of rats. They found that the brains of the adolescent rats produced molecular and epigenetic changes, which was absent in adult rats.
- The results suggested that the pre-exposure to WIN caused a cocaine-induced histone hyperacetylation in the prefrontal cortices of the adolescent rats. This caused changes to chromatin accessibility in several genes that led to the sensitivity to subsequent cocaine exposure.
- The study gave valuable insights to the researchers about how cannabis exposure during adolescence causes subsequent addiction to cocaine among vulnerable sections of the human population.
Space Travel Affects Gene Expression and Causes Cognitive Dysfunction
- A study on rodents conducted by Dr. Janet E. Baulch and her colleagues at the University of California has shown that the radiations encountered during space travel affect gene expression, resulting in cognitive dysfunction in astronauts.
- In the study, the researchers exposed a group of mice to the typical radiation encountered during space travel and subjected them to three behavioral tasks. Using the tasks, the researchers measured the cognitive functions in the hippocampus and perirhinal cortices of the mice.
- After a study of one month, the researchers found that all irradiated mice, irrespective of their age and physical functions, showed significant cognitive dysfunction. This was caused by a change in the ADK protein levels in their hippocampus. The radiation had also changed their gene expression and DNA methylation.
- The study helped the researchers to establish that space travel causes cognitive dysfunction and epigenetic aberrations. It also causes a change in oxidative stress levels leading to the degradation of neuronal architecture and neuroinflammation.
- A similar experiment was also conducted by NASA in which they sent astronaut Scott Kelly to space, while his identical twin brother Mark remained on Earth. After spending one year in space, it was found that Scott's gene expression had changed by 7%, while there was no change in Mark's gene expression.
For our research, we searched for non-peer-reviewed medical/health journals that present new findings and research in the field of epigenetics. Since this is a new field of study, the research around the subject is still in a nascent stage. While we searched exclusively for non-peer-reviewed journals, the scope of the research in such journals is very limited. Hence, we have expanded our search to include a few peer-reviewed medical journals that provide insights into new and interesting research in the field of epigenetics. We have presented five such interesting findings in the above research report.