26 September 2013

Patch for the heart on three-dimensional spirals

Polymer fibers for engineering cardiac tissue

NanoNewsNet based on the materials of American Friends of Tel Aviv University: Putting the Spring Back in Broken HeartsThe cessation of blood flow to the heart causes irreversible death of myocardial cells and is the cause of the formation of scar tissue that is unable to contract.

Due to a shortage of transplants, half of people who have suffered a myocardial infarction die within the next five years. Scientists are trying to solve this problem by developing and improving engineering cardiac tissue that allows replacing damaged areas of the myocardium.

Dr. Tal Dvir (Tal Dvir) from Tel Aviv University and the Center for Nanoscience and Nanotechnology (Tel Aviv University Center for Nanoscience and Nanotechnology) and employees of his laboratory Sharon Fleischer (Sharon Fleischer) and Ron Feiner (Ron Feiner) created fibers shaped like a spiral. These structures allow the engineered heart tissue to perform the function of a bio-pump more successfully. The scientists presented the results of their work in the journal Biomaterials (Fleischer et al., Spring-like fibers for cardiac tissue engineering).

Polycaprolactone fiber, which has the shape of a spiral.
(Photo: American Friends of Tel Aviv University)

"Until now, when growing heart tissue, scientists have used straight fibers as a substrate for contracting cells," explains Dr. Dvir. "But such fibers prevent the reduction of engineering fabric. What we have done is an imitation of spiral-shaped fibers that contribute to the contraction and relaxation of the heart muscle. We have found that when grown on such fibers, the tissue turns out to be more functional."

The heart cells of the patient or animal from which the heart tissue is grown are cultured on three–dimensional substrates that replace the extracellular matrix - a grid of collagen protein molecules that naturally supports the tissue architecture. Over time, the cells come together to form a tissue that generates its own electrical impulses and spontaneously stretches and contracts. Such tissue can then be implanted into the patient's heart to replace the damaged areas and improve the function of the organ.

Dr. Dvir's Laboratory of Tissue Engineering and Regenerative Medicine develops complex tissues for medical use. As for the heart, scientists are constantly searching for ways to create substrates that best reproduce the extracellular matrix and allow for more functional tissue. Earlier this year, Dvir and his colleagues published a study on the integration of gold particles into cardiac tissue to optimize the transmission of intercellular electrical signals.

Recently, Dr. Dvir discovered spiral collagen fibers in the extracellular matrix of the rat heart. Anticipating the advantages that this discovery could give, the researchers decided to recreate these structures. As they had expected, the spiral fibers obtained with the help of the latest technologies demonstrated higher mechanical properties, especially elasticity. Compared to fabrics grown on substrates with straight fibers, fabrics grown on spiral structures contracted with greater force and less mechanical resistance.

"These properties are very important because we are going to transplant tissue into the human heart, which is constantly expanding and contracting," explains the significance of the improvement, the first author of the article Sharon Fleischer.

According to a 2013 report by the American Heart Association, cardiovascular diseases are the cause of two-thirds of all deaths in the United States. Dr. Dvir's laboratory hopes that the tissue grown on substrates with spiral fibers will help in the fight against this epidemic, prolong and improve the lives of millions of people.

However, additional research is needed first: the processes of production of spiral fibers and their assembly into three-dimensional structures need to be optimized. But most importantly, the ability of the improved tissue to improve heart function after a heart attack should be tested on humans, which Dr. Dvir and his colleagues plan to do in the near future during preclinical and clinical trials.

Portal "Eternal youth" http://vechnayamolodost.ru26.09.2013

Found a typo? Select it and press ctrl + enter Print version