The 2007 Bill T. Teague Lectureship in Transfusion Medicine was held May 24 and featured guest lecturer Edward Snyder, MD, FACP. The lectureship, in its 11th year, honors contributions to the blood banking profession by Bill T. Teague, who served as president and CEO of Gulf Coast Regional Blood Center for 31 years.

Dr. Snyder is currently Professor of Laboratory Medicine at Yale University Medical School, Director of the Blood Bank/Apheresis Service at Yale-New Haven Hospital and Director of the Richard Frisbee Hematopoietic Cell Processing Laboratory at Yale Medical Center.  Dr. Snyder is ABIM board-certified in Internal Medicine and Hematology and ABP board certified in Transfusion Medicine. Dr. Snyder is also Director of Shared Resources at the Yale Comprehensive Cancer Center.

Dr. Snyder began the lecture Transfusion Medicine to Cellular Therapy to Regenerative Medicine - The Blood Bank in Evolution with a review of the history of tissue engineering. Coined in 1987, the term “tissue engineering” combines principles from engineering and the life sciences to use the body’s own biological materials to repair, regenerate and ultimately replace damaged organs and tissues, including bone and cartilage.

Tissue engineering offers the promise that humans no longer have to tolerate aging cells and failing organs by providing the means for replacing or repairing diseased or damaged organs. Because the tissues are based on the patient's own cells, engineered tissues should provide the best possible materials for many surgical applications. For example, tissue engineering would eliminate the need for bone grafts and avoid problems associated with artificial replacement joints, such as donor site variances, immunorejection, abnormal wear and tear, and transmission of pathogens.

Cellular therapy is intrinsically connected to tissue engineering; it addresses issues related to understanding and manipulating cell structure-function relationships. Cell therapies and tissue engineering are required for regenerative medicine. Merging several fields, including tissue engineering, biomaterials development and stem cell biology, regenerative medicine seeks to revolutionize the ways we improve the length and quality of life by restoring, maintaining or enhancing tissue and organ function.

Dr. Snyder explained that stem cells are cells with the capacity for unlimited prolonged self-renewal. There are two types of stem cells: 1) embryonic stem cells which can generate all cell lineage and 2) fetal/adult stem cells which provide the committed progenitor cells.

Dr. Snyder then reviewed the mechanism of tissue engineering which starts with a physical scaffold made of an artificial, biodegradable polymer that can be bent to any shape.  The scaffold is seeded with stem cells and growth factors are added. The keys to this process are bioreactors that provide cell culture conditions required for growth and survival of cells. The cells multiply, fill up the scaffold and grow into a three-dimensional tissue. Once implanted in the body, the cells are smart enough to recreate their proper tissue functions. Blood vessels attach themselves to the new tissue, the scaffold melts away, and the lab-grown tissue is eventually indistinguishable from its surroundings. Using this technology, various tissues can be grown in the laboratory, including skin, cartilage, tendon, bone, cornea, salivary glands (for dry mouth), renal tissues, heart valves, venous conduits and blood vessels.

Dr. Snyder reviewed several applications of tissue engineering, including the preparation of living, high-flow vascular grafts for pediatric patients with congenital heart disease.

Lastly, Dr. Snyder commented that the role of blood banks in the field of cellular therapy and regenerative medicine is changing. In addition to providing stem cells for transplants, blood banks and blood centers can participate as providers of mononuclear cells (MNCs) for tissue engineering techniques. Dr. Snyder explained that one way is to reclaim MNCs from leukoreduction filters.  Dr. Snyder concluded the lecture by summarizing the elements of tissue engineering. Dr. Snyder’s PowerPoint presentation can be viewed here.