The scientist and physician looks to stem cells for tomorrow’s transplant techniques.
As a researcher in organ transplantation immunology, Nick Zavazava knows there’s about a 50-50 chance that a transplant recipient’s body will reject a donated organ within 10 years.
That knowledge, coupled with the hopes and expectations patients have for medical science, drives his pursuit of innovative techniques to help people live longer, better lives.
"We aim to increase the tolerance of patients who need organ transplants so their bodies don't reject organs. In particular, we want to eliminate the need for immunosuppressive drugs, which can have serious, even deadly, side effects," says Zavazava, a professor of internal medicine at the UI Carver College of Medicine and a staff physician at UI Hospitals and Clinics.
The opportunity to pursue research and patient care brought Zavazava to Iowa in 2001. He grew up in Zimbabwe, earned his medical degree and doctorate in Germany, and completed additional training in the United Kingdom.
"The UI drew my interest because of the number, as well as a variety, of organ transplants being done," Zavazava says. "The opportunity to be involved in the development of the transplant program was also appealing."
Now, he directs Transplant Research at the Carver College of Medicine and serves as associate director of the Tissue Typing Lab at the nearby Iowa City Veterans Affairs Medical Center. The lab also serves UI Hospitals and Clinics. Serological screening and genetic tissue typing help improve donor-recipient matches and organ acceptance rates.
Before coming to Iowa, Zavazava began studying the immunological properties of embryonic stem cells, which can develop into any type of cell. Working with embryonic stem cells derived from animal models, Zavazava recently used them to create functioning immune system blood cells. Such cells may carry a lower rejection risk than bone marrow cells and might prove useful in transplants to treat diseases like leukemia.
In a paper published in early 2008, Zavazava showed that use of a particular protein could overcome the fact that new blood cells normally are not self-renewing. While the concept is promising, he says, there may be other proteins that do a better job.
Zavazava also works with federally approved lines of human stem cells to find ways to slow cell differentiation. "If you don't control the differentiation of cells, there are dangers of cancer development," he says.
He's also pursuing an idea that may reduce rejection risk and increase the pool of organ donors and recipients. His approach, if feasible, would "prep" transplant recipients with embryonic cells that share, at least in part, the genetic profile of donated organs, thus helping prevent rejection. Zavazava recognizes that embryonic stem cell research is a complex, and at times, controversial issue; his research, like all UI research, follows all state and federal guidelines.
While the central thrust of his research has focused on transplantation, Zavazava also teams up with colleagues to explore how embryonic stem cells could help treat diseases such as hemophilia and diabetes.
Patient care offers a constant reminder that laboratory research aims for safe, effective treatments. Zavazava sees mainly people with allergies at the Allergy-Immunology Clinic at UI Hospitals and Clinics, as well as those born with immunodeficiencies that leave them vulnerable to frequent infections and sinus problems.
"It seriously impacts their lives and their jobs," he says. "These patients would benefit from the renewable source of cells that embryonic stem cells potentially offer."
Zavazava sees promise in the next generation of immunologists, whom he helps train through the Interdisciplinary Graduate Program in Immunology and related Medical Scientist Training Program.
"We have a good reputation for one-on-one training here," he says. "The Internet also has made a huge difference in sharing ideas."
And in the spirit of a true discoverer, healer, and teacher, Zavazava sees the big picture of scientific advancement when it comes to embryonic stem cells.
"There are so many degenerative diseases and issues of aging that likely will benefit from embryonic stem cells, including Parkinson's, diabetes, and hemophilia,” he says. “The first time we have a patient anywhere treated with these cells—whatever the disease—we will all be thrilled.”
Story by Becky Soglin; Photo by Tim Schoon
Oct. 13, 2008