The San Antonio Lung Transplant Protocol

Drs. Luis Angel, Deborah Levine, Stephanie Levine, Scott Johnson, and John Calhoon have spent the past several years developing a protocol — a checklist of procedures — to better prepare donor lungs for transplant. Now used worldwide, it is called the San Antonio Lung Transplant Protocol, or SALT for short. This protocol involves adjusting donors’ ventilators, managing their fluids and many other activities to increase the chances donated lungs can be transplanted in order to help others.

“The process of dying is often very unfriendly to the lung,” Dr. Johnson said. “Historically, only 11 percent of donors are able to donate their lungs.” This is because in many centers technicians with limited medical knowledge are charged with managing patients who have no brain activity. In these types of cases, when the patient is an organ donor and passes away, other organs are taken for transplant, but the lungs are often discarded. However, the SALT Protocol is changing that. As a result of the protocol, the percentage of lungs that can be transplanted has doubled to about 25 percent, Dr. Johnson said.

Preventing organ rejection

The Malú & Carlos Alvarez Center for Transplantation, Hepatobiliary Surgery & Innovationprogram is backed by a vibrant research program conducted at UT Health San Antonio’s Department of Surgery Division of Cardiothoracic Surgery.

One of the team’s research areas is rejection, which occurs when the immune system begins to attack the new lung. It is also one of the most common problems faced by lung transplant recipients. To study this and other problems, researchers have developed the rodent model of lung transplantation. This model allows researchers to develop and test new treatments that may influence and increase overall survival and success for patients undergoing lung transplantation.

“Lungs tend to be rejected more readily than other solid organs,” Dr. Levine said. “It is kind of the Achilles’ heel of lung transplants.” “The long-term success of any lung transplant is determined by chronic rejection,” Dr. Johnson, director of the rodent lung transplant program, added. “Only half of recipients live five years after a transplant, and most succumb in part to rejection.”

Aerosol as a therapy to prevent organ rejection

To develop better ways to treat rejection, UT Health San Antonio researchers use the rodent lung transplant model to test a new nanoparticle aerosol therapy developed by The University of Texas at Austin.

Rejection versus infection

In addition, PET scans (positron emission tomography) performed by UT Health San Antonio’s Research Imaging Center are being studied in the model to determine whether this new technology can be used to differentiate rejection from infection, a common clinical problem that faces many transplant recipients. UT Health San Antonio is one of only a handful of research centers in the U.S. to have a rodent model of lung transplantation.