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The role of prostaglandin and antioxidant availability in recovery from forearm ischemia–reperfusion injury in humans

Carter, Sophie E and Faulkner, Ashton and Rakobowchuk, Mark (2014) 'The role of prostaglandin and antioxidant availability in recovery from forearm ischemia–reperfusion injury in humans.' Journal of Hypertension, 32 (2). pp. 339-351. ISSN 0263-6352

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Abstract

Background: Endothelial dysfunction, manifesting as attenuated flow-mediated dilation (FMD), is clinically important. Antioxidants may prevent this dysfunction; however, the acute effects of oral administration in humans are unknown. Low flow-mediated constriction (L-FMC), a further parameter of endothelial health, is largely unstudied and the mechanisms for this response unclear. Methods: Twelve healthy participants (five women and seven men) completed three test conditions: control; antioxidant cocktail (α-lipoic acid, vitamins C and E); and prostaglandin inhibitor ingestion (ibuprofen). Ultrasound measurements of brachial artery responses were assessed throughout 5 min of forearm ischemia and 3 min after. Subsequently, an ischemia–reperfusion injury was induced by a 20-min upper arm occlusion. Further, vascular function protocols were completed at 15, 30, and 45 min of recovery. Results: Endothelial dysfunction was evident in all conditions. FMD was attenuated at 15 min after ischemia–reperfusion injury (Pre: 6.24 ± 0.58%; Post15: 0.24 ± 0.75%; mean ± SD, P < 0.05), but recovered by 45 min. Antioxidant administration did not preserve FMD compared with control (P > 0.05). The magnitude of L-FMC was augmented at 15 min (Pre: 1.44 ± 0.27%; Post15: 3.75 ± 1.73%; P < 0.05) and recovered by 45 min. Ibuprofen administration produced the largest constrictive response (Pre: −1.13 ± 1.71%; Post15: −5.57 ± 3.82%; time × condition interaction: P < 0.05). Conclusion: Results demonstrate ischemia–reperfusion injury causes endothelial dysfunction and acute oral antioxidant supplementation fails to reduce its magnitude. Our results also suggest that a lack of shear stress during occlusion combined with suppression of prostaglandin synthesis magnifies L-FMC, possibly due to augmented endothelin-1 expression.

Item Type: Article
Uncontrolled Keywords: Allometric scaling; Antioxidants; Flow-mediated dilation; Ibuprofin; Low flow-mediated constriction; Shear rate
Subjects: Q Science > QH Natural history > QH301 Biology
R Medicine > R Medicine (General)
Divisions: Faculty of Science and Health > Biological Sciences, School of
Depositing User: Jim Jamieson
Date Deposited: 19 May 2015 14:32
Last Modified: 19 May 2015 14:35
URI: http://repository.essex.ac.uk/id/eprint/13757

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