Investigator at the Center for Engineering in Medicine & Surgery
Assistant Professor, Harvard Medical School & Massachusetts General Hospital
About Dr. Tessier
Shannon Tessier, PhD, is an Investigator at the Center for Engineering in Medicine and Surgery at the Massachusetts General Hospital and Harvard Medical School. She received her Ph.D. in molecular biology and biochemistry from Carleton University where she studied natural suspended animation across diverse phylogeny including rodents, primates, squids, frogs, and turtles. In 2014 as a Postdoctoral Fellow, she focused on translating these lessons from nature to human cells that are important for diagnostics and therapeutics. Currently, Dr. Tessier is leading a research profile aimed at overcoming barriers in regenerative medicine and organ transplantation, including introducing a new model system to interrogate mechanisms of ischemic injury, developing new approaches to limit ex vivo organ injury, and creating solutions for quantitative assessment of organ viability. The overall goal of her research program is to increase access to organ transplantation using biologically inspired engineering approaches.
One area of focus is to address a fundamental challenge that is shared among all efforts aimed at solving the organ shortage – a lack of critical research tools. Traditional animal models used in experimental transplantation have several drawbacks. The development of a new model that enables easy transplantation, is amenable to high throughput screening, captures the 3D and complex structures of organs, and has a suite of tools to monitor the underlying biology of engraftment would be a tremendous tool for the field. As such, Dr. Tessier was awarded the K99 Pathway to Independence Award to develop the zebrafish as a new research tool in organ transplantation.
Since organs can only be kept alive for a couple of hours during transport, another major research focus is developing new methods to extend the duration of organ preservation. Current preservation practices are highly suboptimal and severely reduce the donor pool. In this capacity, Dr. Tessier and her team are developing high subzero approaches including supercooling (ice-free storage) and an equilibrium freezing method, termed partial freezing. Moreover, the team is developing methods to improve active preservation modalities, including machine perfusion.
The third research thrust focuses on developing new methods for quantitative assessment of graft fitness. Through this work, the team is evaluating two types of viability assessment parameters which measure 1) organ-specific cells and 2) the mitochondrial redox state. Organ specific-cell types such as endothelial cells are released from the graft and carry lineage as well as injury-specific signals. Other viability assessment tools use Resonance Raman Spectroscopy to quantify the redox state of mitochondria from intact tissues.
One area of focus is the application of suspended animation to solve the organ shortage. A critical bottleneck to overcoming the organ shortage is the development of strategies that prolong the length of time organs can remain alive during transport. We are developing a high subzero preservation method that mimics “freeze-tolerance” exhibited by wood frogs in nature which will extend preservation duration from hours to days. We call this method “partial freezing” since ice crystals are restricted to extra-organ and vasculature spaces, and only some water is trapped as ice.
A second area of focus is to use lessons from nature to develop preservation techniques for the field of blood-based diagnostics. Peripheral blood is the most frequently accessed tissue in the clinic; however, the moment blood is removed from its native environment a multitude of degradation pathways are initiated. Improvement of current blood preservation practices has the potential to enable new diagnostic tests and reduce the frequency of clinical errors and misdiagnosis.
Furthermore, increasing storage durations would enable the broad dissemination of new diagnostic technologies by reducing the impact of geographical barriers. We are developing a preservation method which uses hypothermic storage temperatures to slow metabolism and degradation processes, effectively extending standard blood processing times by up to 36-times.
A place where scientific rigor and creativity are matched by a sense of community, the Center for Engineering in Medicine & Surgery is a relatively young and vibrant enterprise that draws strength from its diversity and collective spirit, and from its affiliations with surrounding biomedical research institutions, including Massachusetts General Hospital, the Shriners Hospitals for Children and the Massachusetts Institute of Technology.