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Reduced arterial vasodilatation in response to hypoxia impairs cerebral and peripheral oxygen delivery in hypertensive men

Fernandes, Igor A. ; Rocha, Marcos P. ; Campos, Monique O. ; Mattos, João D. ; Mansur, Daniel E. ; Rocha, Helena N. M. ; Terra, Paulo A. C. ; Garcia, Vinícius P. ; Rocha, Natália G. ; Secher, Niels H. ; Nóbrega, Antonio C. L.

The Journal of physiology, 2018-04, Vol.596 (7), p.1167-1179 [Periódico revisado por pares]

England: Wiley Subscription Services, Inc

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  • Título:
    Reduced arterial vasodilatation in response to hypoxia impairs cerebral and peripheral oxygen delivery in hypertensive men
  • Autor: Fernandes, Igor A. ; Rocha, Marcos P. ; Campos, Monique O. ; Mattos, João D. ; Mansur, Daniel E. ; Rocha, Helena N. M. ; Terra, Paulo A. C. ; Garcia, Vinícius P. ; Rocha, Natália G. ; Secher, Niels H. ; Nóbrega, Antonio C. L.
  • Assuntos: Blood flow ; Blood pressure ; brain ; Cardiovascular ; Carotid arteries ; Carotid artery ; Cerebral blood flow ; Cerebrovascular system ; Chemoreception (internal) ; Doppler effect ; Femoral artery ; Femur ; Hypertension ; Hypoxia ; Musculoskeletal system ; Oxygen tension ; Perfusion ; Research Paper ; Skeletal muscle ; Ultrasound ; Vasodilation ; Veins & arteries ; Vertebrae
  • É parte de: The Journal of physiology, 2018-04, Vol.596 (7), p.1167-1179
  • Notas: https://doi.org/10.1113/JP275984
    This article is highlighted by a Perspective by Hoiland. To read this Perspective, visit
    Edited by: Laura Bennet & Philip Ainslie
    Linked articles
    This is an Editor's Choice article from the 1 April 2018 issue.
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    Linked articles This article is highlighted by a Perspective by Hoiland. To read this Perspective, visit https://doi.org/10.1113/JP275984.
  • Descrição: Key points Hypoxaemia evokes a repertoire of homeostatic adjustments that maintain oxygen supply to organs and tissues including the brain and skeletal muscles. Because hypertensive patients have impaired endothelial‐dependent vasodilatation and an increased sympathetic response to arterial oxygen desaturation, we investigated whether hypertension impairs isocapnic hypoxia‐induced cerebral and skeletal muscle hyperaemia to an extent that limits oxygen supply. In middle‐aged hypertensive men, vertebral and femoral artery blood flow do not increase in response to isocapnic hypoxia, limiting brain and peripheral hyperaemia and oxygen supply. Increased chemoreflex‐induced sympathetic activation impairs skeletal muscle perfusion and oxygen supply, whereas an attenuation of local vasodilatory signalling in the posterior cerebrovasculature reduced brain hyperperfusion of hypertensive middle‐aged men in response to isocapnic hypoxia. The present study investigated whether hypertension impairs isocapnic hypoxia (IH)‐induced cerebral and skeletal muscle hyperaemia to an extent that limits oxygen supply. Oxygen saturation (oxymetry), mean arterial pressure (photoplethysmography) and muscle sympathetic nerve activity (MSNA; microneugraphy), as well as femoral artery (FA), internal carotid artery and vertebral artery (VA) blood flow (BF; Doppler ultrasound), were quantified in nine normotensive (NT) (aged 40 ± 11 years, systolic pressure 119 ± 7 mmHg and diastolic pressure 73 ± 6 mmHg) and nine hypertensive men (HT) (aged 44 ± 12 years, systolic pressure 152 ± 11 mmHg and diastolic pressure 90 ± 9 mmHg) during 5 min of normoxia (21% O2) and IH (10% O2). Total cerebral blood flow (tCBF), brain (CDO2) and leg (LDO2) oxygen delivery were estimated. IH provoked similar oxygen desaturation without changing mean arterial pressure. Internal carotid artery perfusion increased in both groups during IH. However, VA and FA BF only increased in NT. Thus, IH‐induced increase in tCBF was smaller in HT. CDO2 only increased in NT and LDO2 decreased in HT. Furthermore, IH evoked a greater increase in HT MSNA. Changes in MSNA were inversely related to FA BF, LDO2 and end‐tidal oxygen tension. In conclusion, hypertension disturbs regional and total cerebrovascular and peripheral responses to IH and consequently limits oxygen supply to the brain and skeletal muscle. Although increased chemoreflex‐induced sympathetic activation may explain impaired peripheral perfusion, attenuated vasodilatory signalling in the posterior cerebrovasculature appears to be responsible for the small increase in tCBF when HT were exposed to IH. Key points Hypoxaemia evokes a repertoire of homeostatic adjustments that maintain oxygen supply to organs and tissues including the brain and skeletal muscles. Because hypertensive patients have impaired endothelial‐dependent vasodilatation and an increased sympathetic response to arterial oxygen desaturation, we investigated whether hypertension impairs isocapnic hypoxia‐induced cerebral and skeletal muscle hyperaemia to an extent that limits oxygen supply. In middle‐aged hypertensive men, vertebral and femoral artery blood flow do not increase in response to isocapnic hypoxia, limiting brain and peripheral hyperaemia and oxygen supply. Increased chemoreflex‐induced sympathetic activation impairs skeletal muscle perfusion and oxygen supply, whereas an attenuation of local vasodilatory signalling in the posterior cerebrovasculature reduced brain hyperperfusion of hypertensive middle‐aged men in response to isocapnic hypoxia.
  • Editor: England: Wiley Subscription Services, Inc
  • Idioma: Inglês
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