Via ScienceDaily: researchers "have established a new method to patch a damaged heart using a tissue-engineering platform that enables heart tissue to repair itself. ... They were able, for the first time, to combine the use of human repair cells that were conditioned during in-vitro culture to maximize their ability to revascularize and improve blood flow to the infarcted tissue with a fully biological composite scaffold designed to deliver these cells to the damaged heart. With this platform, they could both keep the cells within the infarct bed (in contrast to the massive cell loss associated with infusion of cells alone) and enhance cell survival and function in the infarct bed, where most of the cells would have died because of the obstruction of their blood supply. ... [Researchers] removed the cells of a human heart muscle - the myocardium - leaving a protein scaffold with intact architecture and mechanical properties. They filled the scaffold with human mesenchymal progenitors (stem cells that can differentiate into many cell types) and then applied the patches to damaged heart tissue. The patches promoted the growth of new blood vessels and released proteins that stimulated the native tissue to repair itself."