Cardiac surgeons replace and repair diseased tissue, worn out structures and congenital defects using graft or prosthetic material. The success of surgery, especially in young patients, is limited by the longevity of these materials and their inability to grow with the child.
To address these limitations Professor Massimo Caputo was awarded the 50th anniversary Jules Thorn programme grant in 2015 to develop bioengineered heart valves and conduits.
The team identified a source of vascular progenitor cells (pericytes), which are early-development cells that are already set on the path to become vascular cells – e.g. form veins, arteries or part of the lymphatic system. These were identified from one of the two large veins in the leg of patients undergoing coronary artery bypass graft (CABG) and myocardial tissue (muscle found in the walls of the heart) from children undergoing cardiac surgery. Pericytes can differentiate into vascular smooth muscle and treated correctly can penetrate and colonise the graft. Using this knowledge, we will:
- bioengineer a new kind of prostheses that grow with the child, to repair congenital cardiac defects and avoid further operations
- develop heart valve bio-prostheses seeded with adventitial pericytes from patients’ veins to increase longevity
- use gene therapy to minimise intimal thickening of grafts.