The study is the work of researchers at Benson-Henry Institute for Mind/Body Medicine at Massachusetts General Hospital (MGH) and the Genomics Center at Beth Israel Deaconess Medical Center (BIDMC) and is published online in the open-access journal PLoS One.
Mind-body practices that produce a relaxation response have been used by people across cultures for thousands of years to prevent and treat disease, wrote the authors in their background to the study.
The relaxation response is characterized by reduction in oxygen intake, increase in exhalation of nitric oxide, and lower psychological distress. Many experts see it as the counterpart to the "flight or fight" stress response that has already been shown by a number of studies to have a distinct pattern of physiological and gene expression changes (called "transcriptional profile").
The researchers for this study wanted to test the idea that the relaxation response also produces changes in gene expression.
The researchers recruited three groups of people. In the first group (called the M group) there were 19 long term practitioners who had been practising various ways of producing the relaxation response every day for a long time (for instance with daily yoga, repeated prayer or meditation practice).
In the second group were another 19 people who they called the "healthy controls" (group N1), who were not daily practitioners, and the third group was like the healthy controls group, except these 20 people completed 8 weeks of relaxation response training (this group was N2).
The researchers assessed transcriptional profiles of the people in all three groups from blood samples.
They found the expressions of a total of 2,209 genes were significantly different between groups M and N1, and a total of 1,561 genes were similarly significantly different between groups N2 and N1.
More importantly, however, was the fact 433 of the genes were common to both sets of comparisons: the same ones were different between M and N1 and between M and N2, so even short term practise of the relaxation response appeared to produce changes in these 433 gene expressions.
Further analysis using techniques called gene ontology and gene set enrichment, showed that groups M and N1 (the long term and the short term practitioners of the relaxation response) exhibited similar physiological changes such as in "cell metabolism, oxidative phosphorylation, generation of reactive oxygen species and response to oxidative stress".
A second phase of the study involving 5 N1 healthy controls, 5 N2 short term practitioners, and 6 M long term practitioners, was done to validate a significant number of genes and pathways.
The authors concluded that:
"This study provides the first compelling evidence that the RR [relaxation response] elicits specific gene expression changes in short-term and long- term practitioners."
They wrote that their findings suggest:
"Consistent and constitutive changes in gene expression resulting from RR may relate to long term physiological effects," and that "Our study may stimulate new investigations into applying transcriptional profiling for accurately measuring RR and stress related responses in multiple disease settings."
Dr Herbert Benson, director emeritus of the Benson-Henry Institute and co-senior author of the study said:
"Now we've found how changing the activity of the mind can alter the way basic genetic instructions are implemented," said Benson.
Dr Towia Libermann, director of the BIDMC Genomics Center and also co-senior author of the study added that:
"This is the first comprehensive study of how the mind can affect gene expression, linking what has been looked on as a 'soft' science with the 'hard' science of genomics."
"It is also important because of its focus on gene expression in healthy individuals, rather than in disease states," explained Libermann.
The authors said their study showed that the relaxation response changed the expression of genes involved with inflammation, programmed cell death and the handling of free radicals. Free radicals are normal byproducts of metabolism that the body neutralizes in order to stop damage to cells and tissues.
Co-lead author of the study Dr Jeffery Dusek formerly of the Benson-Henry Institute and now with the Abbott Northwestern Hospital in Minneapolis said:
"Changes in the activation of these same genes have previously been seen in conditions such as post-traumatic stress disorder; but the relaxation-response-associated changes were the opposite of stress-associated changes and were much more pronounced in the long-term practitioners."
Benson said that people across different cultures have been using mind body techniques for thousands of years. They found that it didn't particularly matter which techniques was used, whether it was meditation, yoga, breathing, or repetitive praying, they acted via the same underlying mechanism.
"Now we need to see if similar changes occur in patients who use the relaxation response to help treat stress-related disorders, and those studies are underway now".
Libermann said they used "cutting edge" genomic analysis and the "latest bioinformatics tools to identify potential gene functions, generating hypotheses that can then be tested in laboratory or clinical studies."
"There are a lot of differences in gene expression between one healthy person and another, so it is challenging to analyze the kinds of subtle changes we are seeing and identify what changes are significant and what are just background noise," explained Libermann.
"Genomic Counter-Stress Changes Induced by the Relaxation Response. "
Jeffery A. Dusek, Hasan H. Otu, Ann L. Wohlhueter, Manoj Bhasin, Luiz F. Zerbini, Marie G. Joseph, Herbert Benson, Towia A. Libermann.
PLoS ONE 3(7): e2576, Published online 2 July 2008
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Source: Massachusetts General Hospital .