11/07/2022
By Irma Silva

The Kennedy College of Sciences, Department of Biological Sciences, invites you to attend a master's thesis defense by Jordan Leedberg on "The role of dietary antioxidant supplements in suppressing mechanical muscle strain and inflammation caused by innate immune cells."

Date: Monday, Nov. 21, 2022
Time: 2 to 4 p.m.
Location: Shah 305

Committee:

  • Advisor Peter Gaines, Biological Sciences, University of Massachusetts Lowell
  • Jeffrey Moore, Biological Sciences, University of Massachusetts Lowell
  • Natalie Steinel, Biological Sciences, University of Massachusetts Lowell

Abstract:
Exercise-induced muscle damage (EIMD) is a form of damage caused by forceful eccentric (lengthening) contractions of the skeletal muscle beyond accustomed levels of exercise, which results in physical disruption of muscle fibers. This is most frequently observed in resistance training, marathon running, and other forms of high intensity exercise such as that experienced by military personnel. The initial damage to skeletal muscle fibers observed in EIMD is exacerbated by the pro-inflammatory response mediated by infiltrating immune cells, namely neutrophils and macrophages. Effective treatments for EIMD must therefore address both the primary damage to muscle fibers as well as the secondary damage caused by pro-inflammatory immune cells. In collaboration with the U.S. Army Natick Combat Capabilities Development Command (CCDC) Soldier Center and U.S. Army Research Institute of Environmental Medicine (USARIEM), studies have been performed to characterize interactions of muscle and immune cells in vitro using the Flexcell® FX-5000 system as a model of eccentric strain. This investigation explores the role of multiple nutrients in an in vitro model of EIMD in attempt to identify dietary interventions that may alleviate primary and secondary muscle damage to promote military warfighter recovery from EIMD. Treatments include a polyphenolic extract derived from Montmorency tart cherries (tart cherry extract, or TCE), nutritional supplement Perceptiv®, and metabolic products isolated from various strains of probiotics. Muscle fibers (C2C12-derived) and neutrophils (HL60-derived) were analyzed as monocultures to fully characterize how these in vitro models respond to EIMD with nutrient interventions, which will provide important data to support future tests of muscle-immune cell interactions in response to nutrient interventions. While Perceptiv® suppressed the inflammatory response of neutrophils, this supplement appeared to enhance damage to muscle cultures. Probiotic treatments revealed little effect on strained muscle and require further investigation. On the other hand, TCE successfully suppressed levels of reactive oxygen species (ROS) from neutrophils and lactate dehydrogenase (LDH) damage marker from strained muscle fibers, indicating that this may be an effective treatment for EIMD at the molecular level. This prompted further studies of polyphenolic fruit-derived metabolites ferulic acid, p-coumaric acid, and hippuric acid, which have been identified in human serum following the ingestion of berries. Each of these downstream metabolites demonstrated the capacity for neutrophil ROS suppression, while their effects on muscle fibers remain unclear. Future studies may pursue the use of TCE and fruit-derived metabolites in a muscle-immune co-culture model to fully assess the effect of these interventions on EIMD and inform their use as therapeutic treatments.