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Mayo Clinic Medical Science Blog – an eclectic collection of research- and research education-related stories: feature stories, mini news bites, learning opportunities, profiles and more from Mayo Clinic.

April 16, 2014

The Road to Discovery Runs through Mayo’s Clinical Research Unit

By Robert Nellis


The road to developments that change medicine is jammed with great ideas.  It meanders like a mountain trail in the early stages with many ideas failing and being discarded.  But once an innovative medical breakthrough reaches the point of clinic research, the road runs straight as a Midwest highway through a patient-study unit nestled in Mayo Clinic’s campus in Rochester, Minn.

The Clinical Research Unit (CRU) is the unsung waypoint through which any number of landmark patient studies have traveled en route to improving the lives of millions of people, including revolutionary discoveries in osteoporosis, gastrointestinal distress, sleep apnea and cardiovascular disease, and diseases related to physiology.  Here is a look at one from the CRU atlas of discoveries: diabetes.


Fifty years ago, diabetes treatment involved considerable conjecture. How much insulin — the hormone required to move sugar from the bloodstream to the body’s cells for energy — did a patient need to maintain a safe glucose level? An error in either direction risked dangerously high or low blood sugar. Lacking a clear understanding of the mechanisms underlying diabetes, physicians weren’t sure.

In a series of clinical studies, Mayo Clinic researchers found answers that revolutionized diabetes treatment. By injecting tracers into the bloodstreams of study participants, the researchers were able to follow the intricate and previously unmapped pathways of metabolism. They learned that small amounts of stored glucose are released by the liver when blood sugar is low, keeping glucose concentrations constant between meals. More insulin is needed with a meal to metabolize food.

“Very quickly, we understood what needed to be done to bring glucose levels down, and the insulin doses necessary to accomplish that,” says Robert A. Rizza, M.D., an endocrinologist at Mayo Clinic who led the studies.

As a result of Dr. Rizza and colleagues’ “elegant” studies, the American Diabetes Association proclaimed “the most fundamental questions” about diabetes “were finally addressed.” Intensive insulin therapy, in which patients inject short-acting insulin before each meal and long-lasting insulin for coverage between meals, became standard treatment. Other research applications include the development of precise tools for measuring blood glucose as well as improved insulin and insulin pumps that provide constant therapy.

“To create therapies that benefit patients, we need to precisely measure glucose production and uptake, protein metabolism, the effects of diet and exercise — the list is long,” Dr. Rizza says. “These sophisticated studies could not be done without the Clinical Research Unit.”

To read the full story about Mayo Clinic's Clinical Research Unit, visit Discovery's Edge, Mayo Clinic's research magazine.

Tags: clinical trials, Findings, Innovations, Progress Updates

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