 |
|
Researchers may have found why women have an edge on salt-sensitive hypertension
January 29, 2009AUGUSTA, Ga. - Researchers may have found why women have an edge in keeping a healthier balance between the amount of salt they eat and excrete - at least before reaching menopause.
Premenopausal women are known to have fewer problems with salt-sensitive hypertension and hypertension in general, but afterward their risks are essentially the same as men, says Dr. David Pollock, renal physiologist in the Vascular Biology Center at the Medical College of Georgia.
The reason appears to be related to female hormones and a new-found role of a cell receptor previously thought to be only harmful, he and colleagues report in the February issue of Hypertension.
Their finding points to the need for gender studies on how these endothelin A, or ETA, receptors work in the blood vessels and tubules of the kidney. They also may help explain the swelling that occurs in some patients taking powerful new ETA antagonists, which are in use for pulmonary hypertension and under study for conditions such as diabetic nephropathy and uncontrolled hypertension. These antagonists block the action of ETA receptors which are believed to raise blood pressure and help reshape blood vessels into thick, rigid pipes.
ETA receptors have been considered the evil sibling of endothelin B, or ETB, receptors, which are believed to stimulate nitric oxide production, blood vessel relaxation and salt excretion, Dr. Pollock says. "Normally the ETB receptor system is a decision maker about how much sodium to keep and how much to excrete."
As with Dr. Pollock's rats, people with ETB receptor problems are said to be salt sensitive. "We know from other studies we have done that this endothelin B receptor is critical to keeping you from becoming hypertensive when you eat salt," Dr. Pollock says.
The body gets the sodium it needs from food and a healthy kidney should be able to eliminate excess from a high-salt diet so there is always a balance between what is consumed and excreted. Salt-sensitive hypertension means kidneys hold onto too much salt. When the kidneys realize the blood pressure is getting too high they try to get rid of salt. If they can't, in an ironic twist, blood pressure goes even higher to help literally force salt out of the kidneys. That approach eventually works but over time the high-pressure pounding away at blood vessels can cause heart attack, stroke and/or kidney failure, the type of end stage organ damage associated with hypertension, Dr. Pollock says.
In female rats at least, ETA receptors are less prone to reduce blood flow to the kidneys compared to males and actually increases sodium excretion without increasing blood pressure. Researchers found this by studying a rat missing the ETB receptor. When they gave the animals the protein endothelin to see if it could help them excrete salt without an ETB receptor, males did not respond but females experienced a significant improvement. When they took out the ovaries, female rats responded more like the males. Dr. Pollock says estrogen seems to drive the beneficial action of the ETA receptor. Additionally, researchers found stimulation of the ETB receptor increased urine output and sodium excretion in both sexes, suggesting that it was not a player in the differing responses between males and females.
"According to what we know, blocking the ETA receptor is a good thing and blocking the ETB receptor is a bad thing," Dr. Pollock says. Their findings indicate that actually may depend on whether you are a male or female rat and point to the need for human studies, he adds.
MCG researchers plan more laboratory studies to more specifically determine what different receptor subtypes are doing in the kidney's tubules and vasculature while colleagues at the University of Edinburgh in Scotland are beginning studies to look at how ETA receptor blockers impact sodium excretion in humans.
Medical College of Georgia
Their finding points to the need for gender studies on how these endothelin A, or ETA, receptors work in the blood vessels and tubules of the kidney. They also may help explain the swelling that occurs in some patients taking powerful new ETA antagonists, which are in use for pulmonary hypertension and under study for conditions such as diabetic nephropathy and uncontrolled hypertension. These antagonists block the action of ETA receptors which are believed to raise blood pressure and help reshape blood vessels into thick, rigid pipes.
ETA receptors have been considered the evil sibling of endothelin B, or ETB, receptors, which are believed to stimulate nitric oxide production, blood vessel relaxation and salt excretion, Dr. Pollock says. "Normally the ETB receptor system is a decision maker about how much sodium to keep and how much to excrete."
As with Dr. Pollock's rats, people with ETB receptor problems are said to be salt sensitive. "We know from other studies we have done that this endothelin B receptor is critical to keeping you from becoming hypertensive when you eat salt," Dr. Pollock says.
The body gets the sodium it needs from food and a healthy kidney should be able to eliminate excess from a high-salt diet so there is always a balance between what is consumed and excreted. Salt-sensitive hypertension means kidneys hold onto too much salt. When the kidneys realize the blood pressure is getting too high they try to get rid of salt. If they can't, in an ironic twist, blood pressure goes even higher to help literally force salt out of the kidneys. That approach eventually works but over time the high-pressure pounding away at blood vessels can cause heart attack, stroke and/or kidney failure, the type of end stage organ damage associated with hypertension, Dr. Pollock says.
In female rats at least, ETA receptors are less prone to reduce blood flow to the kidneys compared to males and actually increases sodium excretion without increasing blood pressure. Researchers found this by studying a rat missing the ETB receptor. When they gave the animals the protein endothelin to see if it could help them excrete salt without an ETB receptor, males did not respond but females experienced a significant improvement. When they took out the ovaries, female rats responded more like the males. Dr. Pollock says estrogen seems to drive the beneficial action of the ETA receptor. Additionally, researchers found stimulation of the ETB receptor increased urine output and sodium excretion in both sexes, suggesting that it was not a player in the differing responses between males and females.
"According to what we know, blocking the ETA receptor is a good thing and blocking the ETB receptor is a bad thing," Dr. Pollock says. Their findings indicate that actually may depend on whether you are a male or female rat and point to the need for human studies, he adds.
MCG researchers plan more laboratory studies to more specifically determine what different receptor subtypes are doing in the kidney's tubules and vasculature while colleagues at the University of Edinburgh in Scotland are beginning studies to look at how ETA receptor blockers impact sodium excretion in humans.
Medical College of Georgia
Hypertension Current Events and Hypertension News RSSKey player identified in cascade that leads to hypertension-related kidney damage
A key player in a cascade that likely begins with stress and leads to high blood pressure and kidney damage has been identified by researchers who say the finding may lead to better ways to control both.
American Dietetic Association Releases Updated Position Paper Promoting and Supporting Breastfeeding
The American Dietetic Association has released an updated position paper on breastfeeding that details health benefits for both infants and mothers and encourages promotion of breastfeeding whenever possible.
Web-based nutrition program reduces health care costs for employees with cardiac risk factors
Researchers from Boston University School of Medicine (BUSM) and Boston University School of Public Health (BUSPH) have shown that an employer-sponsored, internet-based diet and exercise program shows promise as a low-cost benefit to lower healthcare costs for those at higher risk for above-average costs and healthcare utilization such as cardiac, hyperlipidemia, hypertension or diabetes patients. These findings appear in the current issue of the Journal of Medical Internet Research.
Experts unveil new CVD guidelines and position papers
Several new guidelines and position papers offering the most up to date information to ensure that clinicians practice evidence-based medicine were released at the Canadian Cardiovascular Congress 2009 this week.
Learning the risks for stroke - and taking action
With this theme in mind, the European Society of Cardiology (ESC) emphasises that most of the risks for stroke are also the major risks for coronary heart disease - and thus the object of the ESC's far-reaching prevention programme.
UC San Diego researchers reverse pulmonary arterial hypertension in mouse models
Researchers at the University of California, San Diego, have identified a key protein that promotes the development of pulmonary arterial hypertension in humans and mice.
Accelerated bone growth may be an indicator of hypertension in children
Children whose bones are "older" than their chronological age may be at an increased risk of hypertension, according to a study reported today (19 October) in Hypertension: Journal of the American Heart Association.
Thyroid surgery safe for older patients, study finds
Thyroid surgery is safe for older patients, say physicians who found only slight differences in rates of complications and hospital readmissions in a multi-year study.
Lupus patients perceive benefit from cardiovascular disease prevention counseling program
According to a new study by Hospital for Special Surgery investigators presented at the American College of Rheumatology meeting on October 21 in Philadelphia, most lupus patients are not aware that their condition puts them at a higher risk for cardiovascular disease and a counseling program is a valuable way to promote education and lifestyle change.
Cost Effectiveness of Blood Pressure Device Evaluated
A study conducted by the University of Rochester Medical Center (URMC) demonstrates that, for certain patient populations, an experimental device that lowers blood pressure may be a cost effective treatment. The implantable device, called Rheos, is in advanced stages of testing for individuals with drug resistant hypertension.
More Hypertension Current Events and Hypertension News Articles
 |
What Your Doctor May Not Tell You About(TM): Hypertension: The Revolutionary Nutrition and Lifestyle Program to Help Fight High Blood Pressure (What Your Doctor May Not Tell You About...) by Mark C. Houston (Author), Barry Fox (Author), Nadine Taylor (Author) A revolutionary, all- natural treatment program for reversing the 'silent killer' affecting more than 50 million Americans. Hypertension is a dangerous and deadly disease. There are no symptoms, so most sufferers have no idea anything is wrong-making more than 45 million Americans ticking time bombs. And while there are many drugs on the market that combat this condition, the costs and side effects are often prohibitive. Now, a leading expert and researcher introduces an all-natural solution. His comprehensive treatment regimen controls high blood pressure using the best of traditional and alternative medicine. Readers will learn about Dr. Houston's own successful all-natural formula, which attacks hypertension from many angles. When used in conjunction with dietary approaches-also... |
 |
Ameal BP Peptide Tablets, Citrus Flavor, Chewable, 90 Tablets (30 day supply) by Ameal S Dietary supplement. Clinically proven, naturally derived. Helps maintain healthy blood pressure. (This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease). 30 Day supply. Ameal BP is a safe and natural dietary supplement that can help you maintain a healthy blood pressure level that is already within the normal range. Following a healthy diet and exercise program as directed by your healthcare provider can also help. The active ingredient, AmealPeptide, is compromised of the natural bioactive peptides (VPP, IPP) that are created during a patented production process involving milk proteins. AmealPeptide helps support healthy cardiovascular function and helps maintain healthy blood vessel tone,... |
 |
Reversing Hypertension: A Vital New Program to Prevent, Treat, and Reduce High Blood Pressure by Julian Whitaker (Author) It strikes one in four North Americans without warning it triples your risk of dying from a heart attack it increases your risk of stroke sevenfold it can lead to kidney disease, diabetes, and blindness and to fight it, you may be taking expensiveand dangerousdrugs. Now Dr. Julian Whitaker, a leading champion of nutritional medicine unleashes a new weapon in the war against hypertension. |
 |
Clinical Management of Hypertension, 8th Edition by Marvin Moser (Author) The eighth edition of Clinical Management of Hypertension continues to update hypertension treatment recommendations with additions and interpretations of new data from treatment trials and guideline comittees. The management guidelines of the Seventh Joint National Committee (JNC) on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure are again reviewed and critiqued in view of new data since these were originally published in 2003. The validity of advising a thiazide diuretic as initial therapy is put in perspective. The 2007 European Society of Hypertension and Society of Cardiology guidelines and new treatment algorithms are also reviewed and evaluated. Recently introduced antihypertensive agents, such as a renin inhibitor and a beta blocker with nitric... |
 |
Healing Hypertension: A Revolutionary New Approach (Health) by Samuel J. Mann (Author) A PIONEERING APPROACH TO OVERCOMING HIGH BLOOD PRESSURE If you are one of the millions of people diagnosed with high blood pressure, this groundbreaking book can change your life. Unique in combining a medical and a psychological approach, Samuel J. Mann, M.D., explains:How you can tell whether or not your high blood pressure is related to emotionsHow to find the medication best suited for you, and when to reduce or eliminate unnecessary medicationHow exploring "hidden" or repressed emotions can reduce your blood pressure and the need for medication Featuring compelling and instructive case histories as well as the latest medical research, Healing Hypertension can help you make sense of your high blood pressure while offering new choices for controlling it. "In... |
 |
Ameal BP Peptide, 60 capsules (30 day supply) by Ameal S Dietary supplement. Easy to swallow. Clinically proven, naturally derived. Helps maintain healthy blood pressure. (This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease). 30 Day supply. Ameal BP is a safe and natural dietary supplement that can help you maintain a healthy blood pressure level that is already within the normal range. Following a healthy diet and exercise program as directed by your healthcare provider can also help. The active ingredient, AmealPeptide, is compromised of the natural bioactive peptides (VPP, IPP) that are created during a patented production process involving milk proteins. AmealPeptide helps support healthy cardiovascular function and helps maintain healthy... |
 |
Rocking The Dog The Gathering (Primary Contributor) |
 |
Hypertension Primer: The Essentials of High Blood Pressure: Basic Science, Population Science, and Clinical Management by Joseph L Izzo (Editor), Domenic Sica (Editor), Henry R Black (Editor) Now in its thoroughly updated Fourth Edition, the Hypertension Primer is a comprehensive, readable source of state-of-the-art scientific and clinical information on hypertension. The book contains 171 short chapters by distinguished experts that cover every aspect of hypertension and its pathogenesis, epidemiology, impact, and management. Highlights of this edition include updated JNC 7 findings regarding special population therapy and clinical management. Chapters are grouped into three well-organized sections--basic science, population science, and clinical management--and each chapter is cross-referenced to other relevant chapters. Each chapter is easily digestible and begins with a bulleted list of key points. |
 |
The DASH Diet for Hypertension by Thomas J. Moore (Author), Mark Jenkins (Author) More than 50 million Americans suffer from high blood pressure, and most of them control it by taking prescription drugs with potentially dangerous side effects. But there is a natural, affordable, and easy-to-manage alternative to medication: the DASH (Dietary Approaches to Stop Hypertension) diet. Developed by a world-class team of doctors and nutritionists, the DASH diet is clinically proven to lower blood-pressure levels and thereby reduce the risk of heart failure, stroke, and kidney disease. Now, with The DASH Diet for Hypertension, readers can benefit from:
• DASH weight-loss and exercise programs for everyday living • The science behind DASH, including calorie worksheets and a... |
 |
Identifying Pulmonary Hypertension Pulmonary Hypertension is a rare, complex disease of the heart and lungs. It most commonly strikes women in childbearing years, though it can affect all ages, races and both sexes. This program will identify what pulmonary hypertension is, and how it is treated. Though there is not yet a cure for this illness, treatments have emerged over the last decade, giving patients hope for a longer, healthier life. Meet patients who are living with pulmonary hypertension and demonstrate how to improve your quality of life. We'll also outline the genesis of the Pulmonary Hypertension Association, and illustrate the power people can have to organize, draw attention to a cause and work to improve the lives of patients and families coping with serious illnesses. This program is part of the award... |
| © 2009 BrightSurf.com |