Daily Archives: March 15, 2014

Hygiene Hypothesis – New Developments

Dr. Garcia’s presentation last class on host-parasite interaction of gut microbes touched on what is known as the hygiene hypothesis. The hygiene hypothesis is a very relevant and interesting topic in connection to evolutionary medicine because it takes into account the history of human exposure to microbes and how our immunoregulatory circuits developed in relation to the presence of microorganisms, especially with gut and skin flora. There is even evidence of evolved dependence to some of these microorganisms due to coevolution. With the changes brought about by technological modernization, the decreasing presence of microbes in our immediate environment has exacerbated systems of inflammation to cause a growing set of chronic autoimmune diseases to emerge. This connection is described in great detail in the book The Hygiene Hypothesis and Darwinian Medicine, edited by Graham A. W. Rook, who is a prominent name in this field of study.

An article in Science Daily from March 2012 titled “Getting the Dirt on Immunity: Scientists Show Evidence for Hygiene Hypothesis” details new supporting evidence for the theory provided by Brigham and Women’s Hospital about this modern predicament. The hospital’s study specifically provided an underlying biological mechanism explaining the hypothesis for the first time in its history, using “germ-free mice” as models. These mice, which were completely lacking in bacteria or any other microbes, were compared to mice living in normal microbial environments and were found to have exaggerated displays of inflammation due to hyperactivity of a unique class of T cells previously linked to disorders such as asthma and colitis in the lungs and colon. Most important of the research’s findings was that exposure to microbes during the first years of life, even if they no longer were as adults, still led to normal immune function, showing the important of early immune conditioning to microbes.

Article: http://www.sciencedaily.com/releases/2012/03/120322142157.htm

Status of Gene Therapy

In class we have touched on the issues surrounding research progressing from animal models to human subjects and we have discussed the possibilities that personalized medicine and the human genome project pose for the future of health care. Gene therapy , in which researchers continue to search for effective but safe vectors to introduce the DNA of  “healthy” versions of genes into diseased patients, is highly related to these discussion topics. This technique offers a huge range of possibilities for countless genetic disorders, but it has many associated complications as well.

This article (accessible through Emory’s network) outlines the troubled past of gene therapy, its setbacks, current research being conducted in the field, and the future of the therapy. Until reading this article, I was unaware of the rocky history of gene therapy. I deemed this important to share with the class so that we would all have a more holistic view of a this development in medicine that has the potential to be viewed through a singular, highly optimistic lens.

Upon reading the gene therapy article, I investigated the death of Jesse Gelsinger and came across this NY Times article about his death and the research study that caused it. This story is a grave reminder of why there are so many regulations in medical research, and that even when everything seems to have been done properly there are still occasionally unpredictable outcomes.

I am interested in following the advancement of gene therapy in the upcoming years, especially since new techniques are expected to be approved in the U.S. by 2016. Gene therapy has the potential to drastically change the way we treat many diseases, but we must not forget the history behind it.