Remembering Philip Aisen, M.D., Influential and Beloved Faculty Member
On April 10, 2020, Einstein lost a member of its early faculty when Dr. Philip Aisen passed away. He was 91.
Renowned as an excellent physician/scientist, as a leader in studying the biochemical and physiological properties of transferrins, and as an outstanding clinician and teacher of medical and graduate students, Dr. Aisen joined the Einstein faculty as an associate in 1960. By 1973, he had risen to the rank of professor in both medicine and biophysics. Colleagues remember him as a thoughtful intellectual with a brilliant mathematical mind, who at turns was loyal, critical, constructive, imaginative, eloquent, diligent, and trustworthy.
“Phil brought biophysics to Einstein and greatly influenced many colleagues with whom he collaborated and who sought his expertise and advice,” noted Irwin Arias, M.D., a long-time colleague and friend, and professor emeritus of medicine at Einstein who was on the faculty from 1957 to 1982. “As a global leader in iron metabolism, he also made important contributions in understanding hemochromatosis and other disorders involving iron metabolism.”
“Aisen” Synonymous with Transferrin
Transferrin binds iron from sites of absorption and forms a complex with the transferrin receptor where it is transported into the cell for release of the iron to sites of utilization. Through his passion for understanding transferrin physiology, Dr. Aisen was a leader in delineating all aspects of this complex process.
In his early studies, he showed that transferrin binds many other metals in addition to iron; his lab clarified the dependency of metal binding and release on the binding of anions such as bicarbonate. Later, in a highly cited work, he demonstrated that the two binding sites of transferrin have different affinities and were cooperative despite being 45 Angstroms apart.
He went on to study the interactions of transferrin with its receptor and, in a seminal work, demonstrated that the receptor modulated the release of iron from transferrin in the cell. After filling in many more details of transferrin function, he collaborated with Dr. Tomas Walz, at Harvard, and reported the structure of the transferrin/transferrin receptor complex, confirming many inferences he’d made based on his biochemical studies.
Dr. Aisen published many highly cited, comprehensive review papers that permitted the scientific community to learn about the intricacies of transferrin physiology and iron metabolism. In 2012, Biochimica et Biophysica Acta published a Special Issue on transferrins that featured a dedication to Dr. Aisen, which stated: “Because of the large body of knowledge contributed by Phil Aisen and his laboratory over so many years, his name has been synonymous with transferrin.”
“His extensive knowledge, fair judgment, and high standards also led to Phil being sought after to serve on editorial boards and grant review panels,” recalled Dr. Denis Rousseau, professor and chair of physiology and biophysics and longtime colleague and friend. Dr. Aisen was on the editorial boards of Biometals, Hepatology, Journal of Inorganic Biochemistry, and Biochemical Journal; and was a member of two NIH Study Section panels: Metallobiochemistry and Arthritis, Diabetes, and Digestive and Kidney Diseases, serving as chair of each.
Influential at Einstein and Beyond
“Phil realized that Einstein was a unique institution and that its sense of inter-disciplinary cooperation was truly special,” recalled another long-time friend and colleague, Irving Listowsky, Ph.D., professor emeritus of biochemistry. “In that regard, he was instrumental in putting together informal groups of investigators interested in metals in biology, particularly the properties of proteins involved in iron metabolism.”
He organized a conference on Proteins of Iron Storage and Transport, which became a biennial event. “It brought together 'iron men and women,'—long before the term became associated with triathlons—so they could discuss research in the field of iron metabolism,” said Dr. Listowsky. “Researchers from all along the Eastern seaboard, as far north as Boston, down through Washington, DC, would come to take part.” These meetings ultimately led to the formation of the International BioIron Society (IBIS).
An excellent clinical teacher and physician, Dr. Aisen was renowned for knowledge of medicine that was both profound and always current. “He cared deeply about Einstein and devoted much energy and creativity to making it an outstanding institution, providing excellent training and research, as well as education for its students,” said Dr. Arias. “He brought science into clinical teaching, provoking students to consider the large issues of mechanisms and unknown aspects of disease.”
In 1964, Dr. Aisen left Einstein to become manager of biochemical research in a newly formed Life Sciences group at the IBM Watson Laboratory, at Columbia University. In 1966 he received a Guggenheim Fellowship as a guest professor at the University of Goteborg, in the lab of Bo Malmstrom, where he learned and became expert in using electron paramagnetic resonance spectroscopy (EPR). He continued using this technique throughout his storied career to delineate the properties of metal binding sites.
He returned to Einstein in 1970, in the department of medicine and as acting chair of biophysics. The latter department was renamed physiology and biophysics following a merger in 1981, and he remained on faculty in both departments until his appointment to emeritus status in 2008.
Dr. Aisen received an A.B. degree (Phi Beta Kappa) in philosophy in 1949 from Columbia College and an M.D. degree from Columbia College of Physicians and Surgeons in 1953. He completed his internships and residencies at Mount Sinai Hospital, where he was chief resident in medicine.
He is survived by his daughter Judith, sons Alex and Paul, and grandchildren and great-grandchildren. May, his wife of 60 years, predeceased him in 2011.
Editor's Note: If you would like to leave a remembrance of Dr. Aisen, please visit our In Memoriam Remembrance page.
Posted on: Friday, July 31, 2020