Aim: This study aimed to assess the effect of acute hyperoxia on cerebral and systemic heamodynamics and the plasma concentration of prostacyclin and thromboxane in patients with stroke.
Methods: Mean blood flow velocity (MBFV), pulsatility and resistance indices of the middle cerebral artery using transcranial Doppler ultrasound before and during acute hyperoxia (4 L of 100%O/15' over facial mask) in 92 participants - 25 patients with acute ischaemic stroke (AIS) that occurred within 72 hours and diabetes mellitus (SPDM), 26 AIS patients without DM (SP) and in 41 healthy controls (HS), were measured. Partial pressure of O (pO), blood pressure and heart rate were measured using pulse oxymeter and pressure gauge, respectively. All the above measurements, as well as cerebral vasoreactivity assessments were performed, before, at the end of the 15 minute period of hyperoxia, and 15 minutes after hyperoxia. The plasma concentration of thromboxane and prostacyclin were determined by ELISA assays.
Results: MBFV increased in both SP and SPDM, while MBFV decreased in HS in response to hyperoxia. Thromboxane correlated negatively and prostacyclin positively with MBVF in the SPDM, although their concentrations did not differ significantly after hyperoxia among groups.
Conclusion: Results suggest impaired vascular reactivity to acute hyperoxia in patients with stroke and the possible role of thromboxane A2/prostacycline in mediating cerebrovascular reactivity in SPDM.
Abbreviations: ANG, II angiotensin II; ASA, acetylsalicylic acid; ATP, Adenosine triphosphate; BP, blood pressure; CBF, cerebral blood flow; CDI, colour Doppler imaging; COX, cyclooxigenase; COVR, cerebrovascular oxygen vasoreactivity; CVR, cerebrovascular reactivity; HR, heart rate; HS, healthy subjects; MBFV, mean blood flow velocity; MCA, middle cerebral artery; PG, 6-keto-PGF1alfa; PGI2, prostacycline; PI, pulsatility index; pO partial pressure of O; RI, resistance index; ROS, reactive oxygen species; SP, stroke patients; TCD, transcranial doppler; TXA, thromboxane A2; TXB, thromboxane B2; VSMC, vascular smooth muscle cell; 20-HETE, 20-hydroxieicosatetraenoic acid.
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http://dx.doi.org/10.1080/02699052.2017.1280853 | DOI Listing |
Free Radic Res
January 2025
Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Patients with hypoxemia require high-concentration oxygen therapy. However, prolonged exposure to oxygen concentrations 21% higher than physiological concentrations (hyperoxia) may cause oxidative cellular damage. Pulmonary alveolar epithelial cells are major targets for hyperoxia-induced oxidative stress.
View Article and Find Full Text PDFIn previous work, we found that short sleep caused sensitivity to oxidative stress; here we set out to characterize the physiological state of a diverse group of chronically short-sleeping mutants during hyperoxia as an acute oxidative stress. Using RNA-sequencing analysis, we found that short-sleeping mutants had a normal transcriptional oxidative stress response relative to controls. In both short-sleeping mutants and controls, hyperoxia led to downregulation of glycolytic genes and upregulation of genes involved in fatty acid metabolism, reminiscent of metabolic shifts during sleep.
View Article and Find Full Text PDFSurv Ophthalmol
November 2024
Department of Ophthalmology, University Hospitals UZ Leuven, Leuven, Belgium; Research Group Ophthalmology, Department of Neurosciences, KU Leuven, Leuven, Belgium. Electronic address:
The retina allows noninvasive in vivo assessment of the microcirculation. Autoregulation of the retinal microvasculature meets the changing requirements of local metabolic demand and maintains adequate blood flow. Analysis of the retinal vascular reactivity contributes to the understanding of regulatory physiology and its relationship to the systemic microcirculation.
View Article and Find Full Text PDFBMC Pulm Med
November 2024
Division of Neonatology, Department of Pediatrics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA.
Background: Prolonged exposure to hyperoxia can lead to hyperoxic acute lung injury (HALI) in preterm neonates. Vitamin D (VitD) stimulates lung maturation and acts as an anti-inflammatory agent. Our objective was to determine if VitD provides a dose-dependent protective effect against HALI by reducing inflammatory cytokine expression and improving alveolarization and lung function in neonatal mice.
View Article and Find Full Text PDFJ Cereb Blood Flow Metab
November 2024
The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Australia.
Asphyxiated neonates must have oxygenation rapidly restored to limit ongoing hypoxic-ischemic injury. However, the effects of transient hyperoxia after return of spontaneous circulation (ROSC) are poorly understood. We randomly allocated acutely asphyxiated, near-term lambs to cardiopulmonary resuscitation in 100% oxygen ("standard oxygen", n = 8) or air (n = 7) until 5 minutes after ROSC, or to resuscitation in 100% oxygen immediately weaned to air upon ROSC ("rapid-wean", n = 7).
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