This study examines the effects of 12-weeks of aerobic exercise training on the mechanisms driving RAGE-mediated inflammation in type 2 diabetic humans.
Activation of RAGE (receptor of advanced glycation endproducts (AGEs)), via binding of AGEs and other ligands, modulates the development and progression of diabetic complications through persistent and cyclic activation of nuclear factor-kappa beta. Targeting RAGE directly as a therapeutic strategy has largely been unsuccessful. However, RAGE signaling can be interrupted, in vivo, by ADAM10 (a disintegrin and metalloproteinase 10) directed proteolytic cleavage of the RAGE ectodomain, and thus creating a soluble isoform of RAGE (sRAGE) that is released from the cell and appears into the circulation. Maintaining high levels of circulating sRAGE is advantageous as sRAGE will sequester RAGE ligands and prevent RAGE cell signaling. Although the exact mechanisms of ADAM10 mediated RAGE release remain undefined, calcium related and other signaling (SIRT1) impact ADAM10. Aerobic exercise presents a unique model for mechanistic study of RAGE release as muscle contraction induces robust calcium signaling, activates SIRT1, and provides stimuli for tissue remodeling and resolution of the metabolic profile that drives inflammation.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
50
12-week supervised aerobic exercise
University of Michigan
Ann Arbor, Michigan, United States
Quantify the Percentage Change in Basal Circulating sRAGE After 12-weeks of Supervised Aerobic Exercise Training.
Serum will be separated from blood samples collected in vacutainer tubes via centrifugation before and after 12-weeks of aerobic exercise training. sRAGE will be quantified in these serum samples via ELISA (Quantikine, Human RAGE Immunoassay) per manufacture's protocol.
Time frame: Baseline and 12 weeks
Quantify the Percentage Change in Basal Muscle RAGE Expression After 12-weeks of Supervised Aerobic Exercise Training.
Basal biopsy derived skeletal muscle RAGE expression will be determined from the vastus lateralis before and after 12-weeks of aerobic exercise training. RAGE expression will be quantified via Western Blot. Muscle samples (\~10 mg) will be homogenized and protein concentration will be determined via BCA assay (Pierce). Samples (20 μg protein) will be diluted in SDS buffer, heated at 85 °C for 5 min, resolved via SDS-PAGE (Bio-Rad Laboratories, Hercules, CA) and transferred to a nitrocellulose or PVDF membrane. Blocking will occur for 1 h and primary antibody (RAGE; Abcam, Cambridge, MA) incubation will occur overnight at 4 °C and quantified vs a standard or total protein.
Time frame: Baseline and 12 weeks
Quantify the Percentage Change in Aerobic Capacity (VO2max) After 12-weeks of Supervised Aerobic Exercise Training.
Maximal oxygen consumption (VO2max) will be established via indirect calorimetry during an incremental treadmill test (Modified Bruce protocol) before and after 12-weeks of aerobic exercise training. Criteria, such as, rating of perceived exertion \>18, respiratory exchange ratio \>1.10, no further increase in VO2 despite increasing workloads, heart rate greater than age-predicted maximum, or volitional fatigue will be used to indicate a successful VO2max was achieved.
Time frame: Baseline and 12 weeks
Quantify the Percentage Change in Insulin Sensitivity After 12-weeks of Supervised Aerobic Exercise Training.
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Insulin sensitivity will be established via calculation of Matsuda Index from glucose and insulin values obtained every 30 minutes during a 75 g Oral GlucoseTolerance Test. Data are represented as percent change. Any change greater than a value of zero indicates an improvement in insulin sensitivity.
Time frame: Baseline and 12 weeks