Cardiorespiratory/Metabolic Laboratory (CRML)
Within the Cardiorespiratory/Metabolic Laboratory, we have one main focal area: the study of nutrition, isolated nutrients and nutraceuticals, and dietary supplements to improve aspects of health and performance—often linked to oxidative stress and inflammation. Our work primarily involves human subjects, although sometimes involves animals and cell culture studies (done in conjunction with other investigators within the College of Health Sciences).
Oxidative stress is a condition in which an imbalance exists between prooxidant and antioxidant levels in such a way that prooxidant production overwhelms antioxidant defenses, often leading to oxidative modification of lipids, proteins, DNA, and other molecules in ways that impair cellular function. The generation of these "reactive oxygen and nitrogen species" (often referred to as "free radicals") occurs in part as a consequence of normal cellular metabolism. Under ordinary physiologic conditions, the body's endogenous antioxidant defense system, in conjunction with exogenous antioxidants consumed through dietary sources, act to protect small and large molecules from modification and destruction via oxidants.
In addition to normal cellular metabolism, radicals can be generated through exposure to a wide variety of environmental and physiological challenges. Two such challenges are the consumption of high saturated fat meals and the performance of strenuous physical exercise. Specifically, oxidative stress may be mediated by an increased activity of radical generating enzymes (e.g., xanthine oxidase), activation of phagocytes, phospholipases, cyclooxygenases, and lipoxygenases, release of heme proteins via destruction of iron containing proteins, through disruption of the electron transport system leading to increased leakage of superoxide radicals, and via decreased antioxidant protection. In these situations when radical production is increased, the use of supplemental antioxidants may prove beneficial.
Although reactive oxygen and nitrogen species are constantly generated in cells and increase with exposure to certain stressors, their production does not necessarily lead to cellular modification and degradation. This is because there exist numerous defenses aimed to minimize their formation, or to neutralize their damaging effects once formed. These are categorized as antioxidant enzymes, antioxidant scavengers and miscellaneous antioxidant compounds, and metal-binding proteins. It should be noted that routine exposure to radicals may lead to an adaptation to improve antioxidant defense within the body (via a process known as hormesis). Such an adaptation may reduce the need for antioxidant consumption in the form of dietary supplements.
Considering the above, many of our investigations focus on the study of oxidative stress in response to acute stressors such as feeding and exercise, and to determine the degree of attenuation of oxidative stress following varying interventions. In particular, investigations routinely include the use of nutrient and dietary supplement treatments in an attempt to minimize oxidative tissue damage, as well as inflammation. Due to the fact that oxidative stress has a strong association with most known human diseases, as well as the aging process, a variety of outcome variables related to both metabolic and cardiovascular health are routinely included within our investigations.