Epigenetics and modern healthcare
to also occur after birth as scientists at McGill University demonstrated that the behaviour of rat mothers to their pups affected the emotional intelligence and stress response of these pups as they matured into adulthood. The rat mothers who had nursed and licked their children, had altered their epigenome at certain genes involved in the development of the brain and behaviour, including the glucocorticoid receptor gene which is involved in the stress response. 5 The environment of the rat pups shaped by the behaviour of their mothers, whether they were adoptive or biological, had actively led to the demethylation of important genes which significantly impacted the emotional state of the rats as they grewup. These experiments shocked geneticists at the time as the results challenged conventional wisdom surrounding DNA and inheritance and could have ground-breaking implications if applied to human health. Connections between a mother’s environment and the genetic expression of her children have also been discovered in humans via observational studies. A blockade by Nazi Germany caused a period of intense starvation in the Netherlands in what became known as the Dutch ‘Hongerwinter’ of 1944 -45. 6 Decades later epidemiologists found correlations between the children of mothers who were pregnant at the time and their likelihood of later developing health problems such as obesity, cardiovascular diseases, and even schizophrenia in some cases. Research has shown the methylation patterns of the DNA of these children differed from those born before and after the years of famine – methyl groups had disrupted certain genes of the babies born during the famine and triggered epigenetic changes. 7 Other observational studies following events that generated physically and emotionally stressful environments such as the North American Ice Storm of 1998 continues to generate data regarding maternal environments and epigenetic inheritance. By understanding how different epigenetic markers impact different genes, the degree of control we have over the activity of our genes should only increase. The medical applications of advancements in the field of epigenetics could transform the way we treat a huge array of diseases including Alzhei mer’s, cancer, diabetes, and others. Breakthrough experiments on rodents, including the discoveries of Duke and McGill Universities, have revealed how the activity of specific genes can be targeted by epigenetic processes triggered by certain conditions. A similar logic could be applied to usher in a new era of highly specific personalized medicine. However, there are significant obstacles that must be overcome before doing so. Although epigenetic changes occur throughout a lifetime, many studies have focused on the babies and young children of both humans and animals, so more research must be carried out in order to understand the means and consequences of fighting the diseases endured bymany adults with an epigenetic approach. Also, much of the epidemiological data that has advanced our understanding of epigenetics in humans has been based on the aftermath of tragedies and so obviously cannot be replicated for ethical reasons while difficulties in applying the results of experiments on rats to progress epigenetic based medicine in humans also remain. Efforts by scientists to trace the human epigenome could prove crucial in furthering this field and this is what the multinational Human Epigenome Project has set out to do, stating how it ‘aims to identify, ca talogue and interpret the genome-wide DNAmethylation patterns of all human genes in all major tissues’. 8 Even though this project will take many years, epigenetic drugs that target the methylation patterns of specific genes could be used before its completion. 5- azacytidine, for example, has been approved by the FDA as a treatment for preleukemia and works to
5 Weaver et al 2006. 6 Carey,N 2012. 7 Zimmer,C 2018. 8 Human Epigenome Project.
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