Controlling High Blood Pressure
Posted by on May 1, 2014 - 9:51am

May Is National High Blood Pressure Education Month, and nearly one in three adults in the United States has high blood pressure, also called hypertension. High blood pressure is dangerous because it increases the risk of stroke, heart attack, heart failure, kidney failure, death.

High blood pressure is called the "silent killer" because it has no symptoms until it causes major damage. A number of FDA-approved drugs, along with lifestyle changes, can help treat this condition.
Read the Consumer Update to get tips for controlling blood pressure and to learn more about approved medications.

High blood pressure at mid age may raise risk for heart attacks and stroke
Posted by on June 16, 2012 - 6:58am

A hike in your blood pressure during middle age significantly raises the risk of having a heart attack or a stroke during your lifetime, according to new Northwestern Medicine research. The study offers a new understanding on the importance of maintaining low blood pressure early in middle age to prevent heart disease later in life.

Men and women who developed high blood pressure in middle age or who started out with high blood pressure had an estimated 30 percent increased risk of having a heart attack or stroke compared to those who kept their blood pressure low.

Previous estimates of a person’s risk of cardiovascular disease were based on a single blood pressure measurement. The higher the blood pressure reading, the greater the risk. The new Northwestern Medicine study expands on that by showing a more accurate predictor is a change in blood pressure from age 41 to 55.

The study is published in Circulation: Journal of the American Heart Association.

“We found the longer we can prevent hypertension or postpone it, the lower the risk for cardiovascular disease,” said lead author Norrina Allen, assistant professor of preventive medicine at Northwestern University Feinberg School of Medicine. “Even for people with normal blood pressure, we want to make sure they keep it at that level, and it doesn’t start increasing over time.”

“There hasn’t been as much of a focus on keeping it low when people are in their 40’s and 50’s,” Allen added. “That’s before a lot of people start focusing on cardiovascular disease risk factors. We’ve shown it’s vital to start early.”    People that maintain or reduce their blood pressure to normal levels by age 55 have the lowest lifetime risk for a heart attack or a stroke.

Men who developed high blood pressure in middle age or who started out with high blood pressure had a 70 percent risk of having a heart attack or stroke compared to a 41 percent risk for men who maintained low blood pressure or whose blood pressure decreased during the time period. Women who developed high blood pressure had almost a 50 percent risk of a heart attack or stroke compared to a 22 percent risk for those who kept their blood pressure low or saw a decrease.

Men generally have a 55 percent risk of cardiovascular disease in their lifetimes; women have a 40 percent risk.

The research was supported by the National Heart, Lung and Blood Institute.

By Marla Paul -- NU health sciences editor

Your genes at work
Posted by on October 2, 2011 - 1:16pm

In one of the largest genomic studies ever, an international research consortium identified 29 genetic variations that influence blood pressure. More than half of these variants were previously unknown. The findings provide insights into the biology of blood pressure and may lead to new therapeutic strategies.

High blood pressure, or hypertension, affects over 1 billion people worldwide. It can damage the body in many ways over time, leading to heart disease, stroke, kidney failure and other health problems.

More than 230 researchers across 6 continents scanned the genomes of over 200,000 European people to identify genetic variants that influence systolic and diastolic blood pressure. They followed up by analyzing the genomes of 70,000 people of East Indian, South Asian and African ancestry. The study was funded by the National Institutes of Health. The results appeared in the September 11, 2011, issue of Nature.

The researchers discovered 16 previously unknown variations. Six were found in genes already suspected of regulating blood pressure. The remaining 10 were found in unexpected locations and provide new clues into how blood pressure is controlled. Individually, the genetic variations increased the risk of hypertension by only a tiny amount. However, for people with multiple variants, the effects were significant.

The researchers developed a blood pressure genetic risk score based on the 29 variants they found. Among people with the top 10% of genetic risk score, 29% had hypertension, compared with 16% of those in the lowest risk group. Higher genetic risk scores were associated with increased blood pressure across ethnic groups. The risk score was also a good indicator of hypertension complications, such as increased thickness of the heart chambers, heart failure, stroke and coronary artery disease.

“This is one of the most important studies of the genetics of high blood pressure to date and a significant step toward finding better therapies for it,” says NHLBI Acting Director Dr. Susan B. Shurin.

A related study by the research group, the International Consortium of Blood Pressure Genome-Wide Association Studies, appeared on the same day in Nature Genetics. This other genome-wide association study identified 4 new genetic regions associated with pulse pressure and 2 linked to mean arterial pressure. The influence of these variants on systolic and diastolic blood pressure turned out to be more complex than expected.

Taken together, these findings suggest new genetic pathways underlying blood pressure regulation. They will also likely open new doors to research into treating high blood pressure.

RELATED LINKS:

What is High Blood Pressure?:
http://www.nhlbi.nih.gov/health/health-topics/topics/hbp/

Hypertension in Women
Posted by on August 13, 2010 - 9:49am

Postmenopausal women have an increased risk of hypertension (high blood pressure), and among older adults, more women than men have hypertension.   As with many other health issues, hypertension research has been conducted predominately in males, and little is known about how women's bodies manage blood flow.   Research conducted by Heidi A. Kluess at the University of Arkansas is focusing on a  better understanding of hypertension in women by using a new technique to examine the release of a neurotransmitter in small blood vessels.

Kluess, an exercise scientist, believes the answer seems to be in the "synapse".  The synapse is the space between the nerve and the vascular smooth muscle, the place where the nerve and blood vessel interact.   A neurotransmitter crosses the "synapse" to activate a receptor, which then causes the artery to constrict.   "There's been a little evidence to say that some of the neurotransmitter breakdown is different in women.   It suggests that when we've been looking at receptors on the smooth muscle, we may have been missing a big part of the story, particularly in women," Kluess said.

The team measured the neurotransmitter adenosine triphosphate (ATP) coming from the small blood vessels (arterioles).  ATP plays a key role in controlling blood flow and blood pressure by causing the diameter of blood vessels to change.   Thus, the constriction of veins associated with hypertension could be related to relatively high levels of ATP in arterioles. So this raises the questions:   Where is the ATP coming from, what tissues are releasing it and how does this change with aging?

To study this,the researchers had to overcome the difficulty of working with very small blood vessels that produced minute amounts of ATP.   A biosensor that was only previously used in brain researcher was utilized that uses a set of enzymes to indirectly measure ATP as it is released.

The research findings suggest that ATP from small arterioles can be measured and that the arteriole wall plays an important role in release and management of ATP. The researchers found that ATP is released mostly from the sympathetic nerves in the arteriole wall and that only a small part comes from the smooth muscle. Considerable research suggests that having a lot of ATP floating around in the blood vessels is not a good thing. The upside of this finding is that the nerve releases ATP in response to nerve signals. However, the mechanisms involved in the release of ATP by smooth muscles are less well understood, Kluess explained, and may result in chronically high ATP release.

The researchers found that the ATP overflow varied considerably with age. Because ATP is associated with vascular growth, it is important during early development when blood vessels are growing, but levels generally decline when people reach their twenties. Elevated levels can be a bad sign during aging when the body is no longer growing and may be a predictor of vascular changes that can be detected years before hypertension is a problem.

Some previous research had suggested that the endothelium – the outer layer of the smooth muscle – produced ATP. However, Kluess’ research showed that the endothelial tissue did not produce ATP. Rather, it decreased levels of ATP and potentially plays a positive role in controlling ATP levels.

“That’s an interesting finding because we know that as people age or develop disease that their endothelium doesn’t work as well,” Kluess said. “That may be a way that ATP increases during aging because the endothelium doesn’t function as well and so can’t buffer ATP quite as well.”

More research is needed to investigate the factors that control ATP overflow and metabolism to reveal the mechanisms associated with age-related change. “We are very much at the beginning of this story,” Kluess said.

Source:   University of Arkansas

Kluess HA, Stone AJ, Evanson KW. ATP overflow in skeletal muscle 1A arterioles. J Physiol.