June 15, 2024

Dr. Daniel A. Popowich Testimonial

“Amongst all human societies, the history of medicine and the art of patient care have been passed down from healers/scientists/doctors to apprentices/disciples/students over and over again. The primary drive for nearly all advancements in medicine has been the curiosity and interest of individuals who seek to answer fundamental questions and to improve upon the current standards of care. I realized early in my medical school training that the foundation and fund of knowledge from which I was now learning was laid by the work of all those who had come before me. Consequently, it became clear to me that embedded in my decision to become a “physician-healer” was my decision to become a “physician-scientist.”

Upon starting my general surgical residency at Northwestern Memorial Hospital, I was fortunate to have had the opportunity to work with, and be mentored by, Dr. Melina Kibbe, the current AAS recorder & Program Committee chair. With her guidance and encouragement, I began to explore opportunities for research funding, and I was privileged and honored to receive the AAS Resident Research Fellowship Award for 2006-2008. The title of my awarded project was “Nitric Oxide Eluting Prosthetic Grafts: Innovative Therapy for Prolongation of Graft Patency.” After completing my third year of clinical duty in 2006, I entered the lab, eager to begin my research experience, yet uncertain as to what lay ahead.

That fall, I attended the Fundamentals of Surgical Research course, provided by the AAS, that immediately preceded the annual American College of Surgeons meeting. Through this course, I began to understand what defined a “surgeon-scientist.” My research included evaluating the basic mechanisms by which nitric oxide (NO) prevents neointimal hyperplasia. Specifically, my work involved studying the pathways by which NO induces smooth muscle cell apoptosis in a p53-independent manner through the formation of reactive oxygen species (ROS) and increased oxidative stress. I was able to apply this mechanism to help further elucidate a finding our lab had already made, that NO decreases neointimal hyperplasia after vascular intervention. In particular, I attempted to elucidate the character and amount of different ROS within the walls of balloon-injured rat carotid arteries. The results suggested that the periadventitial application of NO decreases neointimal hyperplasia after vascular injury by differentially modulating the character and location of ROS within the vessel wall.

As for the research project for which I received the Research Fellowship Award, I collaborated with Dr. Guillermo Ameer at Northwestern University and Drs. Larry Keefer and Joe Hrabie at the NIH. Dr. Ameer designed a novel biodegradable polymer that could be used to coat expanded polytetrafluoroethylene (ePTFE) vascular bypass grafts. Not only was this polymer shown to have some favorable anti-inflammatory and anti-platelet effects in a pig carotid artery bypass model, but the polymer was also able to hold and deliver known quantities of NO-releasing compounds when in solution. By the end of my two years in the lab, we had demonstrated that we could manufacture ePTFE bypass grafts that could release predictable amounts of NO into solution over extended periods of time. Work is being now done to evaluate these grafts’ efficacy and safety in small and large animal models.

I feel that my time in the lab was extremely valuable. During those two years, I was able to write and contribute to many peer-reviewed manuscripts for publication. I was able to travel to and present at many basic science and clinical research meetings across the country. This afforded me the opportunity to meet many other established researchers and clinicians, as well as fellow investigators. These experiences allowed me to see what other novel work was being done in my area of research and beyond.

I began my endeavor to become a “surgeon-scientist” with great eagerness and feelings of intimidation and uncertainty. I credit the AAS and my mentor, Dr. Kibbe, for providing the opportunity, direction, and leadership I needed to realize my goals. I hope that I may one day be able to devote some aspect of my past, current, or future research to improving patient care. It was invaluable to me as a surgical resident with interest in surgical research to have had this opportunity. My time in the lab taught me that regardless of the extent of my surgical training and future surgical practice, I will forever be a student in the school of medicine.”

Daniel A. Popowich, MD,
Northwestern University