Bioreactors Engineer Tissue To Mend Heart Damage

Hugh Pickens writes "Heart attacks usually cause irreversible damage to heart muscle and, because cells lost from the heart do not grow back naturally, leave the organ in a weakened and vulnerable state that may cause another serious condition — called heart failure — if the victim survives. Now a team of scientists led by Tal Dvir from Ben-Gurion University of the Negev in Beer-Sheva has developed a tissue-engineering technique, using the body as a 'bioreactor,' to create a 'patch' made from heart muscle that can be used to fix scarring left over from a heart attack. First, a biodegradable 'scaffold' is seeded with immature cells taken from the hearts of newborn rats. For 48 hours, the scaffold is exposed to a cocktail of growth-promoting chemicals in the laboratory and is then transplanted into a rat's abdomen where it develops a network of blood vessels and muscle fibers. After seven days the patch is removed and grafted onto the animal's heart. A month later the patch has completely integrated itself into the heart, synchronizing its 'beat' with that of the surrounding tissue. 'Using the body as a bioreactor to engineer cardiac tissue with stable and functional blood vessel networks represents a significant improvement in cardiac patch performance over ex vivo (outside the body) methods currently used for patch production,' write the authors. The technique is also being developed for livers and bladders."