Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Key to zebrafish heart regeneration uncovered

06.11.2006
When a portion of a zebrafish's heart is removed, the dynamic interplay between a mass of stem cells that forms in the wound and the protective cell layer that covers the wound spurs the regeneration of functional new heart tissue, Duke University Medical Center scientists have found.

The scientists further discovered that key growth factors facilitate the interaction between the cell mass and the protective covering, encouraging the formation of new heart muscle.

Many cell biologists believe the ability to regenerate damaged heart tissue may be present in all vertebrate species, but that for unknown reasons, mammals have "turned off" this ability over the course of evolution. Zebrafish could provide a model to help researchers find the key to unlocking this dormant regenerative capacity in mammals, and such an advance could lead to potential treatments for human hearts damaged by disease, the Duke scientists said.

"If you look in nature, there are many examples of different types of organisms, such as axolotls, newts and zebrafish, that have an elevated ability to regenerate lost or damaged tissue," said Kenneth Poss, Ph.D., senior researcher for the team, which published the findings on Nov. 3, 2006, in the journal Cell. First authors of the paper were Alexandra Lepilina, M.D., and Ashley Coon.

"Interestingly, some species have the ability to regenerate appendages, while even fairly closely related species do not," Poss added. "This leads us to believe that during the course of evolution, regeneration is something that has been lost by some species, rather than an ability that has been gained by other species. The key is to find a way to 'turn on' this regenerative ability."

The research was supported by the National Institutes of Health, the American Heart Association, the March of Dimes and the Whitehead Foundation.

Scientists previously had suspected that zebrafish regenerated their heart tissue by the direct division of existing cardiac muscle cells adjacent to the injury, Poss said.

However, Poss and colleagues found that the process more closely resembles what happens when a salamander regenerates a lost limb. In the salamander, the site of injury becomes the gathering point for a mass of undifferentiated stem, or progenitor, cells, which are immature cells with the potential to be transformed into other cell types. This mass of undifferentiated cells is known as a blastema. As the progenitor cells receive the correct biochemical cue, they turn into distinct cell types, such as bone, muscle and cartilage, to form the new limb.

Poss believes that when a portion of the heart tissue is removed from zebrafish, a blastema forms at the site of injury. However, the progenitor cells will not achieve their full regenerative potential without interactions with the layer of "epicardial" cells that forms over the blastema. The entire heart is wrapped in a membrane known as the epicardium.

By the third day after injury, the epicardial cells begin to cover the injury site, a process that takes approximately two weeks. The precursor cells within the blastema begin to differentiate into cardiac muscle cells and proliferate within the first three to four days after injury, the researchers found in their experiments.

"Within days of the injury, we find a significant increase in the expression of certain genes in the epicardial cover," Poss said. "These genes are typically expressed only during embryonic development of the cardiovascular system. The epicardial cells mobilize to cover the wound and blastema, and help provide new blood vessels, creating a protective niche where the new heart muscle can grow."

The researchers found that biochemical signaling between the blastema and the epicardium is controlled in part by proteins called fibroblast growth factors, which are involved in wound healing and embryonic development.

"When we blocked signaling by fibroblast growth factors in our zebrafish model, we found that the regeneration gets to a certain point and then stops," Poss said. "The new blood vessels show poor invasion of the newly regenerating cells, halting the formation of new heart muscle."

Poss said that a continued understanding of the processes involved in regeneration of the zebrafish heart could lead to therapies to repair human heart muscle damaged by disease or heart attack.

"Multiple types of progenitor cells have been identified within the mammalian heart, yet it displays little or no regeneration when damaged," Poss said. "By contrast, zebrafish mount a vigorous regenerative response after cardiac injury. Future studies in zebrafish could help us discover why this regenerative ability is lacking in mammals and potential ways to stimulate it."

Richard Merritt | EurekAlert!
Further information:
http://www.mc.duke.edu

Further reports about: Poss Regeneration blastema blood vessel heart muscle injury progenitor regenerate regenerative

More articles from Life Sciences:

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

nachricht Stingless bees have their nests protected by soldiers
24.02.2017 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

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...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

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

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>