HOME >> MEDICINE >> NEWS
'Fickle' enzyme helps protect, but also can promote heart failure, animal study shows

Enzymes that make the gas nitric oxide (NO) not only protect the heart from damage due to high blood pressure or a heart attack, but also promote heart failure through overgrowth and enlargement of the muscle tissue, say animal researchers at Johns Hopkins.

The Hopkins study, to be published in the May 2 edition of the Journal of Clinical Investigation, is believed to be the first to suggest future therapies for heart failure using chemical cofactors that control the enzymes' action.

Nitric oxide's extensive portfolio of natural effects includes the ability to expand coronary arteries, which improves blood flow, and to help regulate the strength of the heart's contraction, notes cardiologist David Kass, M.D., a specialist in enlarged hearts, or hypertrophy, and a professor at The Johns Hopkins University School of Medicine and its Heart Institute.

But there is clearly a dark side, a biological cost, to this activity in some situations when the enzyme changes form, Kass added.

In several experiments, the researchers simulated hypertrophy for up to nine weeks in groups of 10 to 40 male mice, some bred with and some bred without the gene for the most prominent of the NO-making enzymes, nitric-oxide synthase-3 (NOS3).

NOS3 stops functioning normally when levels of its cofactor, called tetrahydrobiopterin (BH4), decrease.

Results not only showed that BH4 levels drop in hypertrophied hearts, but also that NOS3 uncouples, or splits apart, in the absence of its cofactor. Less NO is produced, and instead, the enzyme produces factors that contribute to oxidative stress in the heart. When the researchers restored levels of BH4, it reversed these harmful effects.

In the first experiment, mice without NOS3 better compensated for the damaging stress of hypertrophy, showing less muscle growth, and fibrosis (scar tissue) and better heart function than mice with the enzyme.

Normal mice with the gene for NO
'"/>

Contact: David March
dmarch1@jhmi.edu
410-955-1534
Johns Hopkins Medical Institutions
26-Apr-2005


Page: 1 2 3

Related medicine news :

1. Study says normal but out-of-control enzyme may be culprit that signals some cells to become cancer
2. Scientists develop method to track immune system enzyme in live animals
3. Coenzyme Q10 does not improve Parkinsons disease symptoms
4. Penn study on lung-infecting bacterial enzyme suggests new approach to cystic fibrosis treatment
5. New class of HIV drug attacks previously untargeted enzyme
6. Biologists learn structure of enzyme needed to power molecular motor
7. Scientists stop colon cancer growth in mice by blocking just one enzyme
8. Researchers probe enzyme that may lead to new SARS drugs
9. Study broadens understanding of enzymes linked to tumor promoting molecule
10. Measuring certain enzyme activity in urine shows promise for detection of bladder cancer
11. Elevated GGT enzyme may predict risk of death from cardiovascular disease

Post Your Comments:
(Date:5/21/2013)... Spring is the perfect time to ... filled with whole foods to weather perfect for outdoor ... season the nutrition experts at Brilliant Nutrition highlight five ... , 1. Eating Locally, With the abundance of fresh ... and explore, spring is a great time to take ...
(Date:5/21/2013)... Standard advice for mattress shoppers often consists ... given industry’s less than exceptional satisfaction ratings and the ... Consumer Mattress Reports sets out to revise this advice ... .” , This article addresses several components of the ... not be readily apparent to many shoppers. From prices ...
(Date:5/21/2013)... Patients of Dr. Michael Shenk and Dr. Judd Shenk ... gum disease and would like permanent tooth replacements now have ... laser gum surgery. Gum disease must be treated prior ... of all tooth replacement options. , The Laser Assisted ... by the Food and Drug Administration (FDA) that greatly improves ...
(Date:5/21/2013)... analogues (PGAs), drugs which lower intraocular pressure, are often ... but their use is not without risks. PGAs have ... eye color and other side effects. Now a new ... and lower eyelid drooping and other issues that can ... PLOS ONE . , Researchers from the Massachusetts Eye ...
(Date:5/21/2013)... 2013 HealthSmart continues to grow through ... has required the hiring of new talent in several ... to announce that Dawn Powell has joined the organization ... Director of Account Management in the Central Region and ... Texas. With extensive client management, employee benefits, and product ...
Breaking Medicine News(10 mins):Health News:Brilliant Nutrition Offers 5 Ways to Live Healthier and Inspired this Spring 2Health News:Brilliant Nutrition Offers 5 Ways to Live Healthier and Inspired this Spring 3Health News:Choosing the Best Mattress Simplified in Consumer Mattress Reports’ Latest Article 2Health News:Shenk Dental Care Stimulates Bone Growth for Gum Disease Patients Seeking Dental Implants with Laser Gum Surgery in Atlanta, GA 2Health News:Glaucoma drug can cause droopy eyelids 2Health News:New Talent Joins the HealthSmart Account Management Team 2
(Date:5/21/2013)... May 21, 2013 BioElectronics Corp. (PINKSHEETS: ... electronic devices, announced that CEO, Andrew ... the FDA,s Medical Advisory Committee, Orthopedic and Rehabilitation ... for over the counter sales. "It,s ... medical device classification schema," Whelan said.  "While the ...
(Date:5/21/2013)... TARRYTOWN, N.Y. , May 21, 2013 ... Inc. (NASDAQ: REGN) today announced that the New ... Phase 2a study results of dupilumab (SAR231893/REGN668) in patients ... antibody targeting the alpha subunit of the interleukin 4 ... and IL-13, drivers of Th2 (Type 2 helper T ...
(Date:5/21/2013)... 2013 U.S. spending on specialty prescription drugs ... as cancer, multiple sclerosis and rheumatoid arthritis — is ... 2015, according to a forecast released today by Express ... ) "As we see what,s on ... to act so they can continue to offer an ...
Breaking Medicine Technology:BioElectronics Presents FDA Reclassification Panel 2BioElectronics Presents FDA Reclassification Panel 3Sanofi and Regeneron Announce Publication of Positive Phase 2a Results of Dupilumab in Asthma in the New England Journal of Medicine 2Sanofi and Regeneron Announce Publication of Positive Phase 2a Results of Dupilumab in Asthma in the New England Journal of Medicine 3Sanofi and Regeneron Announce Publication of Positive Phase 2a Results of Dupilumab in Asthma in the New England Journal of Medicine 4Sanofi and Regeneron Announce Publication of Positive Phase 2a Results of Dupilumab in Asthma in the New England Journal of Medicine 5Sanofi and Regeneron Announce Publication of Positive Phase 2a Results of Dupilumab in Asthma in the New England Journal of Medicine 6Sanofi and Regeneron Announce Publication of Positive Phase 2a Results of Dupilumab in Asthma in the New England Journal of Medicine 7U.S. Spending on Specialty Medications Likely to Increase 67 Percent Through 2015 2U.S. Spending on Specialty Medications Likely to Increase 67 Percent Through 2015 3U.S. Spending on Specialty Medications Likely to Increase 67 Percent Through 2015 4U.S. Spending on Specialty Medications Likely to Increase 67 Percent Through 2015 5
Cached News: