The Hindu : Patches of heart tissue grown

Online edition of India's National Newspaper
Sunday, Mar 17, 2002

National

National

Patches of heart tissue grown

By R. Prasad

CHENNAI, MARCH. 16. Using a space-age device called a bioreactor, researchers have grown patches of tissue that beat and respond like a human heart does. One day, perhaps, biomedical engineers will grow new hearts using cells taken from the patients themselves as seeds. Such hearts will not be rejected by the body's immune system.

The researchers — MIT scientists Lisa E. Freed and Gordana Vunjak-Novakovic — have grown tiny patches of heart tissue that beat like a healthy human heart. The tissue contracts in a synchronous way exactly like a beating heart. The researchers used NASA's bioreactor originally meant for studying cell behaviour in space to grow the tissue.

Cells are generally grown in petri dishes, where they settle in a flat layer at the bottom. Such a structure has its inherent problems. But in the bioreactor, the floating cells easily gather into a 3-dimensional structure that resembles real tissues and organs in the human body.

The first step in building a heart patch is to construct a 3-D scaffold using biodegradable material.

This scaffold helps the tissue take the required shape and form ``gap junctions'' on its own.

Nearly five million heart cells are used as seed material. But to function as tissue, the cells must form mutual connections — `gap junctions' — which allow them to exchange electrical signals.

It takes about one week for the bioreactor to produce a patch of tissue five millimetres in diameter and a mere tenth of a millimetre thick. Like real heart tissue, these patches beat spontaneously.

They pick a rate and continue to maintain it if undisturbed. The tissues grown do not have blood vessels and depend on the bioreactor's circulating fluids for oxygen.

Efforts are on to culture heart cells and blood vessels together. The ultimate goal is to grow cardiac tissue that could be used to repair heart defects or to replace tissue damaged in a heart attack.

A more immediate use might be to test new drugs. Bioreactor-grown tissue seems to have a distinct advantage over petri dish grown cells as they mimic the heart better.

Send this article to Friends by E-Mail

National