More evidence of the importance of the gut microbiome? Immune diseases found to inflict identical twins differently

Identical twins are two distinctly different people. While they may have similar characteristics, dress the same way, or even finish each other’s sentences, ask any parent of a pair of identical twins and you will understand how different they are. They may have identical genes (thus, the name) but they do not share identical gene expressions, thanks to epigenetics. Consequently, it’s also epigenetics that play a role in twins’ susceptibility to disease, according to a study from researchers at the Osaka University Graduate School of Medicine. Findings of the study, which are published in the journal Thyroid, indicate which epigenetic factors in specific chromosomes make one twin have a higher risk of autoimmune thyroid disease.

Autoimmune thyroid disease is a condition wherein the body attacks the thyroid gland, which is one of the organs that govern hormone production in the body. It has a central part in the body’s metabolism, as well as other capacities, like sleep and menstruation. Any defect or abnormality in the thyroid can be linked to a variety of disease, including autoimmune thyroid diseases like Grave’s disease and Hashimoto’s disease. In these cases, the body produces anti-thyroglobulin autoantibodies which cause the immune system to attack the patient.

This condition is what associate professor Watanabe of the Center for Twin Research at the University of Osaka is working on. Through examining new diagnostics and focusing on the epigenome of identical twins, his team discovered 23 identical twins that were “discordant for the production of anti-thyroglobulin autoantibodies” and looked to locate the genetic and epigenetic causes.

Watanabe explains: “We hypothesized there are differences in the methylation of CpG sites. The methylation of CpG sites regulates gene expressions. Some diseases like Type 1 diabetes show abnormal methylation patterns.”

Mechanisms that control gene expression, particularly the methylation of CpG locales, is an essential type of epigenetic regulation that happens all over the body. His group the discovered the methylation of CpG locales contrasted in the discordant twins with specific genotypes of four polymorphisms.

“The chromosomes containing these polymorphisms were not the same as the chromosomes containing genes associated with the susceptibility of autoimmune thyroid diseases. The genes susceptible to genetic factors and epigenetic factors are different,” he clarifies.

The examination exhibits the many challenges in diagnosing metabolic disorders like those of the thyroid — which will come from not by simply examining the genes but through genetics and epigenetics.

However, a separate study offers hope in the form of gut microbiomes. A study published in the journal mSphere points out that through early intervention on an infant’s microbiome, certain diseases can be prevented.

The microbiome of children is the ideal breeding ground for microbiomes. These colonies, once they settle in the infant’s gut during their formative years, dictate a person’s resistance to certain diseases for the rest of their lives. However, certain factors can disrupt this development — namely, antibiotic use, the use of formula over breastfeeding, or even caesarian birth, to name a few — which can spell out to a higher likelihood of disease later in life. (Related: How does a C-section birth affect the child? New research suggests children born this way gain more weight than those born naturally.)

Scientists posited that this will produce a long-term effect on the immune system. They also indicated that this procedure could be beneficial for infants that are at risk of unhealthy microbiomes.

To test this theory, researchers gave infants a subspecies of a bacteria found in gut microbiomes, Bifidobacterium longum, for three weeks. They then collected stool samples produced by the samples and checked if they were able to retain the bacteria in the gut. Results indicated that the babies were able to hold the bacteria and were thriving six months after treatment.

This finding was significant, according to the researchers, as this presents that children have gut microbiomes that are easier to manipulate to improve their immune system, as compared to adults.

You can read more stories on the importance of gut microbiomes at Research.news.

Sources include:

Sciencedaily.com

PopSci.com