It’s known that activities like meditation or yoga evoke a relaxation response that can reduce high blood pressure in people that have been diagnosed with hypertension. Exactly how the techniques have that effect isn’t known, but they are recommended; hypertension can lead to stroke or heart attack, events that are experienced by millions of Americans every year. New work has revealed how many genes change in response to relaxation, shedding light on the mechanisms that may underlie the reduction in blood pressure. The findings, by scientists at Beth Israel Deaconess Medical Center (BIDMC), Massachusetts General Hospital (MGH), and the Benson-Henry Institute for Mind Body Medicine at MGH, have been reported in the Journal of Alternative and Complementary Medicine.
"Traditionally, hypertension is treated with pharmacologic therapy, but not all patients respond to drug therapy, and many experience treatment-limiting side effects," noted co-senior author Randall Zusman, MD, the Director of the Division of Hypertension at MGH's Corrigan Minehan Heart Center. "In these patients, alternative strategies are invaluable. In this study, we found that the relaxation response can successfully help reduce blood pressure in hypertensive patients who are not taking medication."
"To our knowledge, this is the first study to test such a mind-body intervention for a population of unmedicated adults with carefully documented, persistent hypertension, and this is the first study to identify gene expression changes specifically associated with the impact of a mind-body intervention on hypertension. Our results provide new insights into how integrative medicine - especially mind-body approaches -- influences blood pressure control at the molecular level,” said Towia Libermann, Ph.D., Director of the Genomics, Proteomics, Bioinformatics, and Systems Biology Center at BIDMC.
For this work, hypertensive participants who were not on medication were asked about depression, anxiety, and stress. They gave a blood sample and attended training sessions to learn how to stimulate the relaxation response, a measurable physiological event that includes decreases in heart rate and respiration. They practiced at home as well.
Eight weeks later, the participants answered the same questionnaire about mood, blood pressure was taken, and blood was drawn again to look at gene expression. The researchers found that thirteen of 24 people who completed the training had a drop in their blood pressure that moved them out of the hypertensive range.
The researchers compared gene expression in people who responded to the relaxation and those who did not. In the responders, there was a change in 1,771 genes between blood draws. Genes that changed have been linked to a variety of pathways including metabolism, circadian rhythm, and immunity control, among others.
"Interactive network analysis of the gene signature identified several molecules, particularly immune system-linked genes, as critical molecules for blood pressure reduction," explained first author Manoj Bhasin, Ph.D., Co-Director of the Genomics, Proteomics, Bioinformatics, and Systems Biology Center at BIDMC.
"Our results suggest that the relaxation response reduced blood pressure - at least in part - by altering expression of genes in a select set of biological pathways," co-first author John Denninger, MD, Ph.D., Director of Research at the Benson-Henry Institute, added. "Importantly, the changes in gene expression associated with this drop in blood pressure are consistent with the physical changes in blood pressure and inflammatory markers that one would anticipate and hope to observe in patients successfully treated for hypertension."