The University of Arizona Medical Center has brought two new surgeons on board to allownthe hospital to resume performing lung transplants.

Surgeons Jesus Gomez-Abraham and Zhain Khalpey are new co-directors of the Heart Transplant and Circulatory Support Program.

Before its last chief of lung transplants left a little more than a year ago, more than 250 such surgeries had been done at UMC.

Adding these two new positions means UMC can once again perform lung transplant surgeries as part of its overall transplantation program.

UMC is also internationally known for heart transplants, having done close to 900, making it one of the biggest centers in the country. The program also offers other cellular transplant programs.

"It is a very comprehensive program in that we have solid organs," says UA Department of Surgery Chair Rainer W.G. Gruessner. "We have cellular components. We have composite tissue transplantation. We do it in children. We do it in adults. And many of the organs we transplant from either diseased donors or living donors."

Gomez-Abraham says the kinds of diseases that make someone eligible for a lung transplant are not exactly common, but they are not rare diseases, either.

"The majority of candidates for this therapy is those patients who have end stage lung disease, excluding cancer," he says. "Those are patients with COPD - chronic obstructive pulmonary disease - idiopathic pulmonary fibrosis, cystic fibrosis, patients who have been transplanted and are having chronic rejection and also patients with pulmonary hypertension, as well".

A considerable number of people in Southern Arizona suffer from these disorders. Phoenix has a transplant center but, once UMC could no longer perform lung transplants, many people from the Tucson area went to California for their surgeries.

Lungs are the trickiest organ to transplant because of problems with rejection, scientists say. Kidney, liver and other transplant surgeries are on the decline.

Lung transplants, in contrast, are rising at a rate faster than any other transplant surgery as success rates are getting better. But, at the same time that more people are getting lung transplant surgeries, the number of donors has declined over the past few years.

And this is where surgeon Zain Khalpey enters the conversation. He is concerned about the availability of organs. Khalpey says about 1,180 people are on the waiting list for lungs. About 300 of those patients die each year. To help fill that void, he is researching ways to make both more lungs and hearts available, by growing them in a lab.

Khalpey's research involves removing all the cells from a non-usable heart or lung so that only a protein matrix remains. Next, he injects stem cells, taken from the waiting patient's fat, into that matrix.

The decellularization and regrowth take place inside a bioreactor, a device Khalepy describes as, "essentially a womb outside of the body, which mimics in 3-D the right stretch forces and signalings that you would need for your stem cell to then engraft onto a matrix of a heart or a lung and become an organ again."

The organ can then be transplanted into the patient, without fear of rejection. This is promising for people who cannot get lung transplants because drugs that suppress the immune system so that it does not reject the organ also make it possible for the cancer to flourish.

Watch interview with Zain Khalpey: