Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Combined, Genes and Environment Affect Health More Than They Do Alone

06.03.2006


Both nature and nurture -- genetic makeup and the environment experienced through life -- combine to influence health and well-being, Duke University Medical Center researchers and their colleagues have determined in four new studies. The researchers showed that people’s genes play a key role in how they respond both biologically and psychologically to stress in their environment.



The researchers presented four studies that examine genetics and the environment on Thursday, March 2, 2006, as part of a symposium organized by Duke researchers at the American Psychosomatic Society annual meeting in Denver. The studies were conducted at Vrije Universiteit in Holland, the Medical College of Georgia and Duke. The studies were funded by the National Institute on Aging and the National Heart Lung and Blood Institute.

Two studies from Duke evaluated effects of a particular mutation in the gene that makes monoamine oxidase-A (MAOA-uVNTR), an enzyme responsible for breaking down serotonin as well as other neurotransmitters in the brain. One form of this mutation causes the gene to make more of the enzyme, while the other form results in less production of enzyme.


Neurotransmitters are chemical signals by which one neuron triggers a nerve impulse in a neighbor. Thus, neurotransmitters are fundamentally responsible for all brain function, and subtle changes in their level or activity can profoundly affect not only brain function but physiological function influenced by the brain.

"There has been considerable speculation that serotonergic nerves in the brain play an important role in glucose metabolism and obesity," said Richard Surwit, Ph.D., a medical psychologist at Duke who led one of the studies. "Drugs that block serotonergic receptors, such as olanzapine, can produce significant weight gain and diabetes, while drugs that stimulate serotonergic neurons, such as fenfluramine, can induce weight loss and improve metabolism."

The researchers’ studies of the effects of mutations in MAOA-uVNTR in 84 people showed that having the active or inactive form of the MAOA-uVNTR mutation appeared to determine how serotonin affected blood levels of glucose and insulin, as well as body mass index.

"It appears that people who carry a particular form of this gene may be more susceptible to developing obesity and diabetes and may be more responsive to therapies that impact on this enzyme," Surwit said.

In a separate study, a Duke research team examined effects of MAOA gene mutations in more than 300 study participants -- half of whom were primary caregivers for relatives or spouses with Alzheimer’s disease and half who were similar to the caregivers but had no caregiving responsibilities. Their data show a significant effect of the MAOA gene on the levels of stress hormones, particularly in men.

"It appears that men with the less active form of the MAOA gene who were subjected to the stress of caregiving, exhausted their ability to mount a stress hormone response during the day and evening hours," said Redford Williams, MD, director of the Behavioral Medicine Research Center at Duke and lead researcher on the study. "Their ability to maintain cortisol and adrenaline at normal levels during the day and evening was significantly lower than that of men with the more active form of the gene, and all the women with both forms of the gene.

"Ultimately, their body’s biological ability to cope with stress became impaired. This exhaustion of their ability to mount a hormonal stress response could place men with the less active form of the gene at higher risk of developing a broad range of health problems as their caregiving duties continue."

The symposium also included a study at the Medical College of Georgia evaluating several families of genes known to affect the stress response and whether the genes affect the risk of developing hypertension, or high blood pressure.

"It has been difficult to show effects of stress on the development of hypertension because it may be that only a subset of people who show a genetic susceptibility will develop high blood pressure after chronic exposure to stress," said Harold Snieder, Ph.D., lead investigator on the work being done at MCG. "Our research shows that effects of different candidate genes on the development of high blood pressure during adolescence depend on the environmental stressors that are present, the gender and the ethnicity, in a group of European American and African American youth that have been followed for 15 years."

In another study reported in the symposium, Eco De Geus, Ph.D., of the Vrije Univeriteit tested blood pressure and heart rate reactivity to acute mental tasks in a sample of 372 adolescent and middle-aged twins. De Geus found that genetic factors had a bigger effect on reactivity to stress than on resting blood pressure.

"Some genes may lie dormant when life is sweet and calm, but swing into action when we are stressed," he said.

The researchers at the symposium said they believe that using genetic markers to determine who is at greater risk of health problems due to both acute and chronic stress and other environmental factors – such as a high calorie diet -- could help identify who might benefit from interventions, such as training in more effective coping strategies, or from closer monitoring for obesity and diabetes onset, the researchers said.

Tracey Koepke | EurekAlert!
Further information:
http://www.mc.duke.edu

More articles from Health and Medicine:

nachricht Unique brain 'fingerprint' can predict drug effectiveness
11.07.2018 | McGill University

nachricht Direct conversion of non-neuronal cells into nerve cells
03.07.2018 | Universitätsmedizin der Johannes Gutenberg-Universität Mainz

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Subaru Telescope helps pinpoint origin of ultra-high energy neutrino

16.07.2018 | Physics and Astronomy

Barium ruthenate: A high-yield, easy-to-handle perovskite catalyst for the oxidation of sulfides

16.07.2018 | Life Sciences

New research calculates capacity of North American forests to sequester carbon

16.07.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>