COX Inhibitor Influence on Skeletal Muscle Fiber Size and Metabolic Adaptations to Resistance Exercise in Older Adults

Abstract

Common cyclooxygenase (COX)-inhibiting drugs enhance resistance exercise induced muscle mass and strength gains in older individuals. The purpose of this investigation was to determine whether the underlying mechanism regulating this effect was specific to Type I or Type II muscle fibers, which have different contractile and metabolic profiles. Muscle biopsies (vastus lateralis) were obtained before and after 12 weeks of knee-extensor resistance exercise (3 days/week) from healthy older men who consumed either a placebo (n = 8; 64±2 years) or COX inhibitor (acetaminophen, 4 gram/day; n = 7; 64±1 years) in double-blind fashion. Muscle samples were examined for Type I and II fiber cross-sectional area, capillarization, and metabolic enzyme activities (glycogen phosphorylase, citrate synthase, β-hydroxyacyl-CoA-dehydrogenase). Type I fiber size did not change with training in the placebo group (304±590 μm(2)) but increased 28% in the COX inhibitor group (1,388±760 μm(2), p < .1). Type II fiber size increased 26% in the placebo group (1,432±499 μm(2), p < .05) and 37% in the COX inhibitor group (1,825±400 μm(2), p < .05). Muscle capillarization and enzyme activity were generally maintained in the placebo group. However, capillary to fiber ratio increased 24% (p < .1) and citrate synthase activity increased 18% (p < .05) in the COX inhibitor group. COX inhibitor consumption during resistance exercise in older individuals enhances myocellular growth, and this effect is more pronounced in Type I muscle fibers.

Single-cell transcriptional profiles in human skeletal muscle

“…Using the cell-type signatures to computationally analyze cell-type proportion in a resistance exercise skeletal muscle transcriptome dataset, we identify an increase in the endothelial cell compartment with training, a decrease in lymphocyte proportion in young women, and an increase in neutrophil proportion with acute exercise. Studies that have examined changes in skeletal muscle capillarization (represented by endothelial cell compartment changes) with resistance exercise training are not entirely consistent, but overall capillarization appears to be influenced by age, training status, and training duration [47][48][49] . The 12 weeks of resistance training in the current study cohort may be too short to induce an increase in measurable capillary density; however, there may be an increase in gene expression within endothelial cells in the early stages of increasing capillary density, which is reflected in the change in the LV.…”

Analgesic and anti‐inflammatory drugs in sports: Implications for exercise performance and training adaptations

“…These findings are in contrast to previous work in the elderly where 12 weeks of resistance training led to greater increases in muscle size and CS activity with ibuprofen. 63 This further highlights the differences between young and elderly in the biological response of NSAIDs taken concurrently with exercise training.…”

A prostaglandin alpha F2 analog protects from statin-induced myopathic changes in primary human muscle cells

“…PTGS is interesting because nonsteroidal anti-inflammatory drugs such as ibuprofen inhibit PTGS and are relevant for pain management 35 . PTGS-inhibitors influence on human skeletal muscle is controversially reported 34,[36][37][38] . In older patients performing resistance exercise under PTGSinhibition treatment, Type I fiber size increased up to 28% compared to control group 38 .…”

“…PTGS-inhibitors influence on human skeletal muscle is controversially reported 34,[36][37][38] . In older patients performing resistance exercise under PTGSinhibition treatment, Type I fiber size increased up to 28% compared to control group 38 . Beneficial effects on skeletal muscle performance have been reported for PTGS up-regulation at mRNA level 39 .…”