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- All Subjects: Metabolism
Over 40% of adults in the United States are considered obese. Obesity is known to cause abnormal metabolic effects and lead to other negative health consequences. Interestingly, differences in metabolism and contractile performance between obese and healthy weight individuals are associated with differences in skeletal muscle fiber type composition between these groups. Each fiber type is characterized by unique metabolic and contractile properties, which are largely determined by the myosin heavy chain isoform (MHC) or isoform combination that the fiber expresses. In previous studies, SDS-PAGE single fiber analysis has been utilized as a method to determine MHC isoform distribution and single fiber type distribution in skeletal muscle. Herein, a methodological approach to analyze MHC isoform and fiber type distribution in skeletal muscle was fine-tuned for use in human and rodent studies. In the future, this revised methodology will be implemented to evaluate the effects of obesity and exercise on the phenotypic fiber type composition of skeletal muscle.
Our current understanding of the mitochondrial genome was revolutionized in 2015 with the discovery of short open reading frames (sORFs) that produced protein products called mitochondrial-derived peptides (MDPs). Interestingly, unlike other proteins produced by the organelle, these MDPs are not directly involved in the electron transport chain but rather serve the role of metabolic regulators. In particular, one of these peptides called MOTS-c has been shown to regulate glucose and fat metabolism in an AMPK-dependent manner. With its capacity to enter the mitochondria and impact gene expression, MOTS-c has also displayed the ability to increase aerobic exercise performance by triggering elevated synthesis of the HO-1 antioxidant. Overall these findings position MOTS-c as a promising treatment for metabolic diseases as well as a potential dietary supplement to boost ATP availability.
This pilot study aimed to ascertain the potential for keto acid supplementation in the attempt to supply adequate protein building blocks to healthy populations, with the caveats that said supplementation 1) would utilize non-synthetic methods, 2) offer an alternative to high-phosphate protein supplies such as ruminant animals, and 3) reverse the ill effects of ammonia load by reducing nitrogen intake and consuming ammonia as a fuel for the process of protein synthesis. This proposed solution turns to orange juice and certain varietals of potato juice for their familiarity to consumers, innate nutritional values, and potential for mass-production by many existing companies. The work contained here represents the first phase of experimentation: qualifying the presence of α-keto-analogues of amino acids in these types of produce which, with transamination, could yield the amino acids necessary for adequate protein intake.
Results suggest that these juices do not contain adequate α-keto-analogs of amino acids to supplement proteins in either healthy or ill individuals.
Disclaimer: The initial goal of this project was to present this information as a podcast episode as a part of a series aimed at teaching the general public about human physiological adaptations. Due to the circumstances with COVID-19 we were unable to meet to make a final recording of the podcast episode. A recording of a practice session recorded earlier in the year has been uploaded instead and is therefore only a rough draft.