Research
Aging is a process of physiological and functional decline accelerated by a physically inactive lifestyle. Physically inactive older adults are at risk for developing metabolic disease (insulin resistance, glucose intolerance) and loss of muscle mass resulting in a poor quality of life and loss of physical independence.
Research Projects
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Cellular & Molecular Mechanisms
Understanding the cellular and molecular mechanisms of skeletal muscle growth and metabolic function in aging muscle.
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Therapeutic Tools
Utilizing therapeutic tools (nutritional, contractile analogs, pharmacological) to limit muscle and metabolic deficits that occur with physical inactivity in aged muscle.
Human Vastus Lateralis Muscle Stem Cell Figure. Adult humans possess a multipotent population of muscle stem cells, which play a large role in regenerating muscle following damage/adaptation following various physiologic stimuli. This image was captured at 20X magnification. (A) Overlaid image with muscle fiber borders, stem cells, and myonuclei with white arrows denoting stem cell location. (B) Muscle fiber border and fiber-type removed, to highlight stem colocalization with stem cells. (C) Muscle fiber-type content with several fibers marked with either “I” or “II” in order to classify fibers as type-I slow oxidative or type-II glycolytic, respectively.
Mouse Gastrocnemius Muscle Fiber-Typed Figure. Dissecting individual muscles during our animal experiments allows a unique perspective into which muscles/fiber-types are affected by various physical inactivity stimuli. Image was captured at 10X magnification. (A) This particular cross section includes 4392 total muscle fibers (0.064% Type I, 8.8% Type IIa, and 90.5% Type IIb/x). Yellow boxes denote areas highlighted in panels B and C. (B) Generally, mouse muscle is comprised of vastly more fast glycolytic muscle fibers (IIa & IIb/x) compared to human muscle. Therefore, it is often useful to analyze portions of the medial/lateral gastrocnemius heads when translating to human data as those portions tend to contain muscle fiber-types more akin to what are found in human muscle. (C) As mentioned previously, dissecting the entire muscle allows us to visualize very large areas of muscle. Interestingly, the reagent used to visualize the muscle fiber borders (staining the laminin protein) also identifies blood vessels and nerve bundles.
The Drummond lab utilizes a host of molecular biology techniques and functional assays to further enhance the understanding of the mechanisms involved in metabolic dysfunction and muscle atrophy in aging skeletal muscle and in response to physical inactivity. Specific questions are addressed using mechanistic mouse models complemented with controlled physical inactivity experiments in older adults (bed rest). Clinical muscle samples are often paralleled with whole body measurements of physical mobility, muscle strength and size capitalizing on the resources of the skeletal muscle exercise research facility (SMERF) and the expertise of the SMERF investigators within the Department of Physical Therapy.
We also utilize generous services from the University of Utah’s Center for Clinical and Translational Sciences to assist with our inpatient and outpatient older adult experiments and analysis. Dr. Drummond collaborates with investigators across the Health Sciences and College of Health, many of whom are associated with the Diabetes and Obesity Metabolism Center.