Featured Research

from universities, journals, and other organizations

Something You Don't Hear Much About: Hearing Loss Tied To Heart Disease

Date:
March 24, 2005
Source:
Harvard University
Summary:
There are a few people in the world who get heart disease after they begin to lose their hearing. Harvard Medical School researchers have found a gene responsible for this, and they're using that information to better understand heart problems faced by millions of people.

Christine Seidman (left) and Libin Wang check the progress of an experiment that isolated a gene change responsible for both hearing loss and heart failure. (Staff photo Justin Ide/Harvard News Office)

There are a few people in the world who get heart disease after they begin to lose their hearing. Harvard Medical School researchers have found a gene responsible for this, and they're using that information to better understand heart problems faced by millions of people.

Related Articles


Two members of a family who suffered progressive hearing loss and then underwent heart transplants got Christine Seidman, a professor of medicine, interested in the strange connection. Their hearing loss began early in life. It progressed for at least 10 years before they started to experience shortness of breath, chest pains, and other symptoms of congestive heart failure. This condition, in which heart muscles become too weak to pump enough blood to the lungs and heart, kills about 260,000 people a year. However, the heart transplants received by these two people were successful and they are now living healthy lives.

Taking the novel connection to heart, Seidman and her colleagues set out to find the cause. Their studies of family members with the syndrome revealed that they shared a mutation in a gene called eya4.

To look more closely at how changes in the protein made by this gene work, the researchers turned to the tiny zebrafish. Half the length of a finger, these fish possess an eya4 gene remarkably similar to that of humans. What's more, zebrafish have almost transparent bodies. You can see and even take pictures of their hearts and watch the blood it pumps go from place to place.

The fish are easy to maintain and manipulate, and they can serve as a good model of the heart failure that affects millions of people and is becoming epidemic in this country.

Breaking the hearts of fish

The fish received injections of genetic blockers that prevented their eya4 gene from producing a key protein that turns on other genes necessary for normal heart function. When the team took photographs of these modified fish, "We saw dramatic changes in the size of their chest cavities due to increased fluid surrounding the heart," Seidman recalls. "A closer look showed the organ was contracting, or beating, abnormally."

As a final check, the team tracked the movement of blood along the body to the tail. They saw a profound decrease in blood flow in the doctored fish compared to that in wild fish.

"The importance of this discovery goes beyond finding the cause of an unusual human mutation," Seidman notes. Many genes that cause heart failure have been found by her team and other investigators, but they code for individual tasks such as making a heart beat or building an ear bone. In contrast, eya4 takes part in regulation of a large repertoire of genes needed for normal heart function. Thus, "studying eya4 gives us a new tool to overview the whole of heart function," Seidman says. "That's the real excitement of this work."

Much of the work was done by Jost Schonberger and Libin Wang, two postdoctoral fellows on the team. Jonathan Seidman, a professor of genetics at Harvard Medical School and Christine's husband, also participated in the research, which is described in detail in the April issue of Nature Genetics.

Do fish go deaf?

In people with the eya4 mutation, hearing loss starts decades before the symptoms of a failing heart appear. "We could therefore use the hearing loss as a [predictor] for heart disease," Seidman notes.

"But we are also very interested in the role of eya4 in hearing," she continues. She wants to explore the heart of hearing, so to speak. While the researchers can use zebrafish to investigate some aspects of this, it's technically easier to probe hearing by using mice as models. Scientists don't know much about how fish hear, or if they go deaf.

The mouse work has already begun. Seidman is intrigued to learn why a gene that has survived hundreds of millions of years of evolution from fish to humans got involved in both hearing and heartbeats. "The heart and ear don't seem to have much in common," she says. "But, if an efficient way to regulate gene expression evolves in an organ such as the ear, evolution might well want to conserve it and use it for other purposes in other tissues. A fuller understanding of what happens when a critical regulator like eya4 doesn't function normally can lead us to novel and creative ways to redress medical problems that involve both the heart and hearing."


Story Source:

The above story is based on materials provided by Harvard University. Note: Materials may be edited for content and length.


Cite This Page:

Harvard University. "Something You Don't Hear Much About: Hearing Loss Tied To Heart Disease." ScienceDaily. ScienceDaily, 24 March 2005. <www.sciencedaily.com/releases/2005/03/050323134233.htm>.
Harvard University. (2005, March 24). Something You Don't Hear Much About: Hearing Loss Tied To Heart Disease. ScienceDaily. Retrieved December 20, 2014 from www.sciencedaily.com/releases/2005/03/050323134233.htm
Harvard University. "Something You Don't Hear Much About: Hearing Loss Tied To Heart Disease." ScienceDaily. www.sciencedaily.com/releases/2005/03/050323134233.htm (accessed December 20, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Saturday, December 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Best Tips to Curb Holiday Carbs

The Best Tips to Curb Holiday Carbs

Buzz60 (Dec. 19, 2014) It's hard to resist those delicious but fattening carbs we all crave during the winter months, but there are some ways to stay satisfied without consuming the extra calories. Vanessa Freeman (@VanessaFreeTV) has the details. Video provided by Buzz60
Powered by NewsLook.com
Sierra Leone Bikers Spread the Message to Fight Ebola

Sierra Leone Bikers Spread the Message to Fight Ebola

AFP (Dec. 19, 2014) More than 100 motorcyclists hit the road to spread awareness messages about Ebola. Nearly 7,000 people have now died from the virus, almost all of them in west Africa, according to the World Health Organization. Video provided by AFP
Powered by NewsLook.com
Researchers Test Colombian Village With High Alzheimer's Rates

Researchers Test Colombian Village With High Alzheimer's Rates

AFP (Dec. 19, 2014) In Yarumal, a village in N. Colombia, Alzheimer's has ravaged a disproportionately large number of families. A genetic "curse" that may pave the way for research on how to treat the disease that claims a new victim every four seconds. Duration: 02:42 Video provided by AFP
Powered by NewsLook.com
The Best Protein-Filled Foods to Energize You for the New Year

The Best Protein-Filled Foods to Energize You for the New Year

Buzz60 (Dec. 19, 2014) The new year is coming and nothing will energize you more for 2015 than protein-filled foods. Fitness and nutrition expert John Basedow (@JohnBasedow) gives his favorite high protein foods that will help you build muscle, lose fat and have endless energy. Video provided by Buzz60
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins