Journal article
Combined inorganic nitrate/nitrite supplementation blunts alpha-mediated vasoconstriction during exercise in patients with type 2 diabetes
Nitric oxide, Vol.118, pp.17-25
01/01/2022
DOI: 10.1016/j.niox.2021.10.006
PMID: 34718145
Abstract
Aims: Patients with type 2 diabetes mellitus (T2DM) have reduced vasodilatory responses during exercise partially attributable to low nitric oxide (NO) levels. Low NO contributes to greater alpha-adrenergic mediated vasoconstriction in contracting skeletal muscle. We hypothesized boosting NO bioavailability via 8wks of active beetroot juice (BRA, 4.03 mmol nitrate, 0.29 mmol nitrite, n = 19) improves hyperemia, via reduced alpha-mediated vasoconstriction, during handgrip exercise relative to nitrate/nitrite-depleted beetroot juice (BRP, n = 18) in patients with T2DM.
Methods: Forearm blood flow (FBF) and vascular conductance (FVC) were calculated at rest and during handgrip exercise (20%max, 20contractions.min(-1)). Phenylephrine (alpha(1)-agonist) and dexmedetomidine (alpha(2)-agonist) were infused intra-arterially during independent trials to determine the influence of alpha-mediated vasoconstriction on exercise hyperemia. Vasoconstriction was quantified as the percent-reduction in FVC during alpha-agonist infusion, relative to pre-infusion, as well as the absolute change in %FVC during exercise relative to the respective rest trial (magnitude of sympatholysis).
Results: Delta FBF (156 +/- 69 to 175 +/- 73 ml min(-1)) and Delta FVC (130 +/- 54 to 156 +/- 63 ml min(-1).100 mmHg(-1), both P < 0.05) during exercise were augmented following BRA, but not BRP (P = 0.96 and 0.51). Phenylephrine-induced vasoconstriction during exercise was blunted following BRA (-17.1 +/- 5.9 to-12.6 +/- 3.1%, P < 0.01), but not BRP (P = 0.58) supplementation; the magnitude of sympatholysis was unchanged by either (beverage-by-time P = 0.15). BRA supplementation reduced dexmedetomidine-induced vasoconstriction during exercise (-23.3 +/- 6.7 to-19.7 +/- 5.2%) and improved the corresponding magnitude of sympatholysis (25.3 +/- 11.4 to 34.4 +/- 15.5%, both P < 0.05).
Conclusions: BRA supplementation improves the hyperemic and vasodilatory responses to exercise in patients with T2DM which appears to be attributable to reduced alpha-adrenergic mediated vasoconstriction in contracting skeletal muscle.
Details
- Title: Subtitle
- Combined inorganic nitrate/nitrite supplementation blunts alpha-mediated vasoconstriction during exercise in patients with type 2 diabetes
- Creators
- Joshua M. Bock - Roy J. and Lucille A. Carver College of MedicineKenichi Ueda - Roy J. and Lucille A. Carver College of MedicineAndrew J. Feider - Roy J. and Lucille A. Carver College of MedicineSatoshi Hanada - Roy J. and Lucille A. Carver College of MedicineDarren P. Casey - Roy J. and Lucille A. Carver College of Medicine
- Resource Type
- Journal article
- Publication Details
- Nitric oxide, Vol.118, pp.17-25
- Publisher
- Elsevier
- DOI
- 10.1016/j.niox.2021.10.006
- PMID
- 34718145
- ISSN
- 1089-8603
- eISSN
- 1089-8611
- Number of pages
- 9
- Grant note
- P30 CA086862 / National Institutes of Health; United States Department of Health & Human Services; National Institutes of Health (NIH) - USA 1-16-ICTS-015 / American Diabetes Association
- Language
- English
- Date published
- 01/01/2022
- Academic Unit
- Anesthesia; Physical Therapy and Rehabilitation Science; Fraternal Order of Eagles Diabetes Research Center
- Record Identifier
- 9984295056302771
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