What are the conditions of stress that will cause yoiu to develop high blood pressure, if you lack a novel gene called phosducin? New studies to find out whether stress increases blood pressure were directed by scientists at the University of Freiburg and Muenster in Germany, and the Medical College of Wisconsin in Milwaukee, in collaboration with other institutions in Europe and Canada.
The results are published online this month in the Journal of Clinical Investigation in advance of the print publication. Also see the Medical College of Wisconsin's Dec. 2009 press release, "New Stress-related gene Modulates High Blood Pressure in Mice & Men."
New research has for the first time established a link between a novel gene, phosducin, and the blood pressure response to stress in mice as well as humans. The German team, led by Lutz Hein M.D., in collaboration with Monika Stoll, Ph.D., generated mice lacking the phosducin gene and compared them with normal mice that have the gene.
The mice lacking this gene developed high blood pressure under various conditions of stress. The mechanism of this gene's action appears to be directly involved with specific sympathetic nerve cells The cells show a distinct increase in their activity translating into an increase in blood pressure.
The findings were then tested using DNA from 342 African Americans enrolled in an ongoing high blood pressure study at the Medical College, and 810 French Canadians at the University of Montreal. The volunteers were then asked to perform certain standardized stress-related activities which confirmed the beneficial action of the gene in humans.
In African Americans as well as French Canadians, certain phosducin DNA variants serve as markers and can identify patients with an increased blood pressure response, for example when taking a math test. Additional cohorts from Europe also confirm this relationship with regard to blood pressure. Now all you have to do is find out what causes you to have a stress response that will raise your blood pressure, if you have that variant in your DNA.
What the findings of this study give you is an idea of how to reduce your stress response the best way you can before your blood pressure gets raised numerous times daily each time you have a new stress response that your body interprets as a reason to raise your blood pressure. Some people get this response because they lack the gene that keeps your blood pressure normalized during even the slightest stress--that is what events your body perceives as stressful.
The new studies provide unique insights into the mechanisms of blood pressure stress response. How do you treat the blood pressure rise from the slightest stress events? Would slow breathing or meditation several times a day control it, or would you need to take drugs or eat certain nutrients in foods? Those are some avenues being researched.
If you lack this gene and have high blood pressure due to stress, scientists know this is a distinct form of high blood pressure that needs a distinct form of treatment. Who are the scientists that conducted the recent study?
Ulrich Broeckel, M.D., associate professor of pediatrics, medicine, and physiology, and chief of pediatric genomics at the Children's Research Institute conducted these studies in collaboration with Ted Kotchen, M.D., associate dean for clinical research; Allen Cowley, Ph.D., Chairman and Harry & Gertrude Hack Term Professor in Physiology; and James J. Smith and Catherine Welsch Smith Professor in Physiology; and Howard Jacob, Ph.D., Warren P. Knowles Professor in Human and Molecular Genetics and director of the Center at the Medical College. Other collaborators were Michael Harrison, graduate physiology student, as well as Dr. P. Hamet at the University of Montreal.
Scientists in this study looked at unique techniques, for example, a nerve traffic recording technique. What researchers are using are sophisticated and sensitive methodologies to assess neuroadrenergic function in different experimental animal models. But more studies and research are needed.
What's left for scientists now is to find what type of treatment is best and how to determine the therapeutic implications. For further information, check out the site for the Medical College of Wisconsin.
In medical terms, the study found that, "Candidate gene–based association studies in 2 different human populations revealed several SNPs in the PDC gene to be associated with stress-dependent blood pressure phenotypes. Individuals homozygous for the G allele of an intronic PDC SNP (rs12402521) had 12–15 mmHg higher blood pressure than those carrying the A allele." In plain language, blood pressure is stress-dependent, if you have the gene variation being tested.
The study reported, "These findings demonstrate that PDC is an important modulator of sympathetic activity and blood pressure and may thus represent a promising target for treatment of stress-dependent hypertension." Read the study online, "Phosducin influences sympathetic activity and prevents stress-induced hypertension in humans and mice," published Dec. 1, 2009 in the Journal of Clinical Investigation.
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