Human Heart Regenerates Cells Automatically: One Percent Each Year

[Guest guest]

Human Heart Regenerates Cells Automatically: One Percent Each Year

_http://www.naturalnews.com/026761_heart_cells_disease_labeling.html_

(http://www.naturalnews.com/026761_heart_cells_disease_labeling.html)

 

 

NaturalNews) In a groundbreaking new study, researchers from the

Karolinska Institute in Sweden have demonstrated that heart cells are able to

regenerate themselves, overturning the conventional wisdom that the body cannot

replace damaged heart cells.

 

 

Researchers immediately hailed the study as providing new hope for

prevention and treatment of diseased hearts.

 

 

**I think this will be one of the most important papers in cardiovascular

medicine in years,** said Dr. Charles Murry, a heart researcher at the

University of Washington in Seattle. **It helps settle a longstanding

controversy about whether the human heart has any ability to regenerate

itself.**

 

 

Unlike most cells in the body, heart cells mostly stop reproducing

themselves relatively early in life. When injured, the heart tends to simply

scar,

rather than replacing damaged tissue the way other organs do. For decades,

scientists assumed that the heart was simply incapable of natural

regeneration.

 

 

This idea was challenged in 1987 by Piero Anversa, now a researcher at

Harvard Medical School. Anversa believes that the heart regenerates a rate

allowing it to replace all of its cells four times in 80 years. Clinical

evidence for this idea has been lacking, however.

 

 

To determine rates of cell regeneration in animals, scientists typically fl

ood an animal's body with radiation and track the rate at which

non-radioactive cells replace the radioactive ones. In one of these so-called

pulse

labeling experiments in mice, researchers found that mouse heart cells

regenerated at a rate of about 1 percent per year -- much lower than the rate

hypothesized by Anversa, but still higher than the conventional wisdom.

 

 

Although pulse labeling experiments are banned in humans, researcher Jonas

Frisen realized that the technique could be replicated by measuring heart

cells* levels of the radioactive isotope carbon-14.

 

 

Because carbon-14 decays at a fixed rate, researchers can use levels of

the isotope to estimate the dates of organic materials that are tens of

thousands of years old -- but the isotope decays far too slowly to be used in

dating of living cells.

 

 

Aboveground nuclear tests in the 1960s, however, injected large quantities

of carbon 14 into the air that were then absorbed by life forms around the

world. When aboveground testing was banned, atmospheric levels of the

isotope began to drop. This means that the amount of carbon-14 contained in a

given cell could serve as an indicator of what year that cell was formed.

 

 

Examining the heart tissue of 50 people over the course of four years,

Frisen and colleagues found that on average, new heart cells appeared to

replace old ones at a rate of approximately 1 percent per year in youth and 0.5

percent per year by age 75.

 

 

**If you exchange cells at this rate it means that even if you live a very

long life you will not have exchanged more than 50 percent of your

cells,** Frisen said. **So at any given time your heart is a mosaic of cells you

carry with you from birth and cells that that have been added later to

replace cells that have been lost during life.**

 

 

Anversa said he was *ecstatic* at the study*s findings.

 

 

**Now let*s discuss the magnitude of the process, and that will let us

think about how we can apply this concept to heart failure,** he said.

 

 

Researchers now hope to find ways to stimulate the regeneration of heart

cells, as a way to avoid heart transplants and help people recover from

heart attacks. Alternatively, the heart might already be regenerating heart

cells after an injury but those cells might simply be dying without getting

established. If this is the case, scientists could find a way to help those

new cells survive.

 

 

Frisen also noted that different regeneration rates might explain why some

people are more predisposed to heart disease.

 

 

**We are interested in studying whether some heart diseases could

potentially be caused by too low an ability to replace heart cells,** he said.

 

 

Sources for this story include: _www.reuters.com_ (http://www.reuters.com/)

; _www.nytimes.com_ (http://www.nytimes.com/) .

 

(http://www.papercut.biz/emailStripper.htm)