Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How fish mend a broken heart

03.11.2006
New evidence to explain how a common tropical fish mends a broken heart may suggest methods for coaxing the damaged hearts of mammals to better heal, researchers report in the November 3, 2006 issue of Cell, published by Cell Press.

The researchers found that the hearts of zebrafish harbor progenitor cells that spring into action to restore wounded heart muscle. Cells from a membrane layer that surrounds the heart, called the epicardium, follow suit, invading the wounded cardiac tissue and stimulating the growth of new blood vessels.

"Zebrafish can survive pretty massive injury to the heart--the loss of about a quarter of their ventricle," said Kenneth Poss of Duke University Medical Center. The ventricle, which receives blood and then pumps it back out to the body, is one of two chambers that make up the fish heart. "This study gets at some of the important mechanistic questions about how they rebuild the heart, and some of the key factors that contribute."

In contrast to zebrafish, the cardiac damage and scarring caused by heart attacks is a major killer among humans, making "the inability to replace damaged cardiac muscle one of the most prominent regenerative failures of mammals," wrote Alexandra Lepilina and Ashley Coon, the study's first authors.

However, mammalian hearts have been found to contain rare populations of progenitor cells, they added. As in zebrafish, the hearts of adult mammals, including humans, are also housed inside an epicardium, a tissue about which little is known.

"Scientists haven't paid much attention to the epicardium in adults," Poss said. "These findings in fish should encourage more exploration of what adult epicardium can do.

"There is the potential that these cells could be utilized for therapies."

The ability to regenerate tissue is a feature shared among vertebrate species, the researchers said. However, particular animals, including certain amphibians and fish, display an "elevated regenerative spectrum, with many more tissues capable of impressive regeneration," they said. For instance, certain newts or salamanders can regenerate limbs, spinal cord, retina, brain, and heart tissue.

While progenitor cell populations have been identified within most mammalian organs, including skin, skeletal muscle, brain, and heart, these cells vary widely in frequency and the ability to regenerate damaged or lost tissue, they said. In most mammalian organs, progenitor cells can restore cells lost in the course of normal organ function or after minor injury but cannot regenerate after major damage or removal of structures.

"It is believed that the capacity for regeneration is an ancestral condition that has occasionally been lost in the course of vertebrate evolution." Poss said. "Thus, most biologists suspect that the machinery to optimize regeneration from progenitor cells is present, but lies dormant, in mammals."

In an earlier study, Poss and his colleagues found that zebrafish have a unique ability to regenerate cardiac muscle after major injury. They further suspected that illumination of the fishes' ability might offer important insights into "how heart regeneration is naturally optimized."

In the current study, they found that heart regeneration proceeds through two coordinated stages. First, a mass of undifferentiated, pre-cardiac cells form. Those progenitor cells then begin to differentiate and divide, to replace the damaged heart muscle.

In the second step, the epicardium surrounding the heart chambers "lights up" with activity as developmental genes switch on, Poss said. The epicardium expands to rapidly cover the wounded heart muscle.

A subset of those epicardial cells then alters their identity, invading the wound and providing essential new blood vessels to the growing muscle.

They further found that the two-part regeneration process is coordinated by so-called "fibroblast growth factor" (Fgf) signals. Fgf signals are known for their ability to encourage invasive cell behavior, Poss explained.

Indeed, they found, heart muscle cells produce the growth factor, while epicardial cells harbor receptors that are triggered by the signal. When the researchers experimentally blocked the Fgf signal, heart regeneration failed.

"It is tempting to speculate that the ability to mobilize epicardial cells and cultivate such a cardiogenic environment is a primary reason why zebrafish, as opposed to other laboratory models, effectively regenerate [heart muscle]," the researchers concluded. Indeed, they added, mammalian hearts typically show insufficient blood vessel growth after a heart attack.

"Experimental attempts to modify this deficiency are underway, including delivery of growth factors or bone marrow-derived cells that may promote [the formation of new blood vessels]…Success in these pursuits or by directly utilizing epicardial cells or their progenitors could prove favorable for encouraging regeneration from mammalian cardiac progenitor cells."

Heidi Hardman | EurekAlert!
Further information:
http://www.cell.com

More articles from Life Sciences:

nachricht Decoding the genome's cryptic language
27.02.2017 | University of California - San Diego

nachricht New risk factors for anxiety disorders
24.02.2017 | Julius-Maximilians-Universität Würzburg

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Safe glide at total engine failure with ELA-inside

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded after a glide flight with an Airbus A320 in ditching on the Hudson River. All 155 people on board were saved.

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded...

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Cells adapt ultra-rapidly to zero gravity

28.02.2017 | Health and Medicine

An Atom Trap for Water Dating

28.02.2017 | Earth Sciences

New pop-up strategy inspired by cuts, not folds

27.02.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>