Resident Research Award Highlights Diet-Based Strategy to Prevent Vein Graft Disease

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This year’s SVS Foundation’s Resident Research Award is being presented to Kaspar M. Trocha, MD, for his research on vein graft disease. As a member of the laboratories of C. Keith Ozaki, MD, and James Mitchell, MD, along with co-first author Peter Kip, MD, and microsurgeon Ming Tao, MD, the group studies the effects of food intake immediately before surgery on vascular adaptations.

Resident Research Award winner Dr. Kaspar M. Trocha (right) shown with his mentor, Dr. C. Keith Ozaki.

Dietary restriction (reducing food intake without malnutrition) has been a topic of special interest in the science community for decades, and restricting calories in the long term has been shown to extend life and health span in a variety of species. It can also protect from overexuberant responses to trauma and ischemia-reperfusion.

Dr. Mitchell found that the benefits from long-term food restriction could be acquired as rapidly as in a few days, pointing to a potential for implementing dietary restriction recommendations prior to elective surgery.

The response to stress benefits seen following brief dietary interventions are mediated by the gaseous signaling molecule hydrogen sulfide (H2S). H2S is strongly upregulated by dietary restriction and this “rotten egg” gas seems to be protective for the cardiovascular system and has been demonstrated to be involved in vasodilation, inflammation, and atherogenesis, according to the researchers. The group’s experiments thus tested short-term protein restriction (a more feasible dietary approach for patients that observed to induce H2S) in a microsurgical mouse vein graft model.

The team discovered that cutting all protein from the animal diet for just 1 week before surgery led to increased levels of the enzyme cystathionine-gamma-lyase (CGL) that makes H2S, higher levels of the protective gaseous molecule, less early vein graft inflammation, and less eventual occlusive vein graft disease even though the animals were returned to their usual high-fat diet postop. The group also confirmed these results by constructing a new mouse strain that overexpresses CGL, and these mice were protected from vein graft disease. Conversely, blocking this enzyme negated all the beneficial effects of the dietary restriction.

According to Dr. Trocha and his colleagues, “short-term pre-operative protein restriction and manipulation of H2S stand as novel, economical approaches to enhance vein graft durability and perhaps even lessen peri-operative complications, and we are in the early stages of testing this strategy in vascular surgery patients.”

Dr. Trocha’s research was supported by the Harvard-Longwood Research Training in Vascular Surgery NIH T32 Grant and Dr. Ozaki’s NIH and American Heart Association grants. The Resident Research Award is given to one individual each year as determined by the SVS Research and Education Committee with the intent of motivating physicians early in their training to pursue their interest in research that explores the biology of vascular disease and potential translational therapies. The recognition includes plenary presentation at the Vascular Annual Meeting, a $5,000 award and a 1-year complimentary subscription to the Journal of Vascular Surgery.

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