Harvest Technologies Corp. won approval from the Food & Drug Administration for a 42-patient trial of its technique to use concentrated autologous bone marrow cells to treat patients undergoing coronary artery bypass grafts.

The FDA’s investigational device exemption allows the Plymouth, Mass.-based firm to study whether its BMAC system can help re-grow dead or damaged heart tissue. The two phase feasibility trial will see a one patient group injected with the concentrated stem cells after CABG surgery and a control group treated with CABG alone.

Harvest said the stem cells might be able to become functional myocardial cells, which make up the muscular middle layer of the heart’s wall. The company’s device is able to concentrate patients’ own bone marrow stem cells in approximately 15 minutes in the operating room.