April Flowers for redOrbit.com – Your Universe Online
In the wake of a heart attack, the heart’s tissues sustain irreparable damage. Cells in the heart cannot multiply and the heart muscle contains very few stem cells, meaning the tissue is unable to repair itself. The damaged tissue therefore becomes fibrotic and cannot contract correctly.
Looking for new, innovative methods to restore heart function, scientists have been exploring cardiac “patches;” these patches could be transplanted into the body to replace damaged heart tissues.
Dr. Tal Dvir, of Tel Aviv University’s (TAU) Department of Molecular Microbiology and Biotechnology and the Center for Nanoscience and Nanotechnology, has been working with his PhD student Michal Shevach and other colleagues to literally set a gold standard in cardiac tissue engineering. The results of this study were recently published in the Journal of Materials Chemistry B.
One of the largest challenges in developing cardiac patches is ensuring that engineered tissue can mimic the heart’s coordinated electrical system, which controls heartbeat and rhythm. Dr. Dvir’s team integrated cardiac cells with nanofibers made of gold particles to form functional, engineered tissues to overcome this issue, with the goal of optimizing electrical signaling between cells.
Heart cells have proteins on their surface that are responsible for transferring electrical signals. The process of tissue engineering itself, however, leads to the loss of these proteins. Dr. Dvir says that the heart cells will start to produce them again naturally, but they take time to develop. The patient may not have this time. This is where the gold nanofibers come in — they can fill the role of electrical connectors until the cells are able to produce their own connector proteins again.
Cells taken from patients or animals are placed onto a 3D scaffolding made of biomaterials — basically any matter or surface that interacts with biological systems — to create new tissues. This organizes the cells into the proper formation as they grow. The team employed various chemical and physical processes to integrate gold nanoparticles into their scaffolds, which allowed the cells to interact with each other.
A scanning electron microscope and various other measures of electrical activity were used to observe the nanoparticles on the fibers and check conductivity. Significantly stronger contractions were observed with cells placed on gold-embedded scaffolding when compared to those without the gold. More importantly, the cells demonstrated effective electrical signaling by contracting in unison.
New treatment options are sorely needed for heart attack victims because 50 percent die within five years of their initial attack. Functioning, transplantable tissue could save lives, and improve the patient’s quality of life.
Dr. Dvir and the team at his Tissue Engineering and Regenerative Medicine Laboratory plan to continue their research by evaluating the potential for the gold infused cardiac patches to improve function after heart attack through pre-clinical tests in the lab and, eventually, clinical trials with patients. Dr. Dvir says that the ideal method would be to use a patient’s own cells when building the new tissue, therefore avoiding the risk of rejection.
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