Hiển thị các bài đăng có nhãn aging. Hiển thị tất cả bài đăng
Hiển thị các bài đăng có nhãn aging. Hiển thị tất cả bài đăng

Thứ Năm, 9 tháng 5, 2013

Reverse aging? Scientists discover protein that could turn hearts younger

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No matter how young an individual may feel at heart, little can currently be done to counteract the effects of natural cardiovascular aging. As an adults ages, his or her heart grows larger and its walls thicken, often leading to a disease known as diastolic heart failure. This is the most common form of age-related heart failure and despite the fact that it affects millions, there is no known treatment.

However, in a breakthrough discovery, researchers at Harvard University have pinpointed a protein that, when injected into the blood of mice, is able to reverse aging in the heart within 30 days – effectively turning old hearts young again.

“We’ve developed this potentially broadly-acting rejuvenative protein and we are excited to understand its potential in humans,” study author Amy Wagers, a professor of stem cell and regenerative biology at Harvard University, told FoxNews.com.

Wagers and her colleagues identified the protein, known as GDF-11, over many years of research. Because aging occurs more or less uniformly throughout the body, the researchers had long suspected that one specific factor essentially signals to all of the body’s tissues how they should function as a context of age.

“We looked in the blood stream, because the blood carries things to all parts of the body; that would be a logical place for that substance to be traveling,” Wagers said.

Eventually, they zeroed in on the protein GDF-11.

“(The protein) was very high in the blood of young mice and low in the blood of old mice, suggesting that could have an impact on aging,” Wagers said.

After discovering the protein, Wagers and her colleagues decided to study the impact it had on cardiovascular aging. They injected GDF-11 into the blood streams of older mice in order to increase their GDF-11 levels to match the levels found in younger mice.

After 30 days, the researchers examined the hearts of the older mice, which had previously shown thickened walls similar to those in older humans. The researchers found that the thickening had reversed, and the hearts of the older mice now looked almost identical to those of the younger mice.  

“The older hearts really did look almost the same at a gross anatomy level. I’m certain there are still some differences, but it was quite dramatic how much rejuvenation (there was),” Wagers said.

While previous research has shown regenerative treatment through the use of stem cells in spinal and muscular-skeletal systems, Wagers and her team were shocked to discover that a protein could have a regenerative effect on the heart.

“I was very surprised, actually,” Wagers said. “The process I had in my mind was that it was a process of controlling function in normally regenerative tissues and replacing cells all the time.”

Because GDF-11 can be circulated through the blood system, it offers a “very therapeutically accessible opportunity,” Wagers noted.

Researchers estimate that four to five more years of testing and research still needs to be done before clinical trials could begin.  However, Wagers and her colleagues hope to one day use this discovery to help reverse cardiovascular aging in humans as well.

“We hope that by providing this protein, we could reverse that heart enlargement, and that would have a benefit to the many patients who have this form of heart disease,” Wagers said.

This research was published on May 9 in the journal Cell


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Thứ Sáu, 3 tháng 5, 2013

The fountain of youth? Brain region found to control aging

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For the first time, a brain region has been found that may control aging throughout the whole body, a new study reports.

A signaling pathway in the brain region known as the hypothalamus could speed up or slow down aging in mice. If it applies in humans, the discovery could open up possibilities for slowing age-related diseases and increasing life span.

"There's really not much understanding regarding the mechanism of aging," said senior author Dr. Dongsheng Cai, a molecular pharmacologist at Albert Einstein College of Medicine in New York. [Extending Life: 7 Ways to Live Past 100]

The process of aging could involve chaotic, passive changes in individual tissues or organs, or it could be controlled centrally by a single organ or both, Cai told LiveScience.

The hypothalamus, an almond-size structure deep inside the brain, is known to control important functions, including growth, development, reproduction and metabolism. Now, Cai and his team have found that an immune system pathway in the hypothalamus also has a role in controlling aging. Usually, the immune system is involved in fending off infection or damage, but studies have also linked inflammatory changes with age-related conditions, including cardiovascular disease and neurodegenerative diseases. Still, these changes weren't known to actively trigger aging.

Making mice tick

In the study, Cai and his colleagues probed the hypothalamus's role in aging in mice. The team studied a protein complex called nuclear factor kappa-light-chain-enhancer of activated B cells (NF-B), which plays a central role in inflammatory processes.

The researchers showed that activating the NF-B pathway in the mouse hypothalamus sped up aging, demonstrated by decreased muscle strength and size, skin thickness and learning ability. The activation led to aging throughout the body that shortened the life span of the mice.

In contrast, when the researchers blocked the NF-B pathway, the mice aged more slowly and lived about 20 percent longer than mice that didn't receive the treatment.

Furthermore, activating the NF-B pathway led to a drop in the levels of gonadotropin-releasing hormone (GnRH), a neuron-generating chemical, and a subsequent decrease in the development of new neurons. GnRH is known to regulate reproductive processes, but seems also to be necessary for maintaining youthfulness, Cai said.

When the researchers injected GnRH into the hypothalamuses of mice, it promoted neuron generation and decelerated aging. The team gave daily GnRH injections to old mice over an extended period, finding that the treatment slowed cognitive decline due to aging.

Putting the brakes on aging

GnRH treatment represents a potential means of slowing the progress of aging or age-related diseases, the researchers say. Interfering with the immune response in the hypothalamus could also be a promising approach, Cai said, though he added that the GnRH treatment might be more practical given current technology.

Aging researcher Caleb Finch of University of Southern California Davis School of Gerontology, who was not involved in the work, called it a "brilliant study." Finch has previously argued that the hypothalamus contains "pacemakers" that control the rate of aging. The new study's approach showed a more modest increase in life span than approaches such as calorie restriction (which has been shown to extend life span in mice), Finch said. "Nonetheless, the case is now powerfully made for the role of the neuroendocrine mechanisms as modulators of aging."

Next, the researchers hope to gain a deeper understanding of the molecular function of the hypothalamus in controlling aging and life span. "There are a lot of details we don't know," Cai said, such as the other molecules that are involved. The team is ultimately interested in translating their work into clinical efforts to slow down aging.

The findings were reported online May 1 in the journal Nature.

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