Retinal Arteriolar and Middle Cerebral Artery Responses to Combined Hypercarbic/Hyperoxic Stimuli

Kisilevsky, M.; Mardimae, Alexandra; Slessarev, Marat; Han, Jay; Fisher, Joseph A.; Hudson, Chris

doi:10.1167/iovs.08-1854

Cited by 17 publications

(12 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The ocular flow is highly sensitive to the partial pressures of arterial O 2 and CO 2 (PaO 2 and PaCO 2 ) (Hayashi et al 2010;Kisilevsky et al 2008;Luksch et al 2002). The effect of these on ocular circulation may have been limited during the imposed exercise, since the changes in PaO 2 and PaCO 2 in the present study were assumed to be subtle.…”

Section: Technical Considerationsmentioning

confidence: 77%

Effects of dynamic exercise and its intensity on ocular blood flow in humans

2011

View full text Add to dashboard Cite

Visual performance is impaired when the ocular blood flow decreases, indicating that ocular blood flow plays a role in maintaining visual performance during exercise. We examined the ocular blood flow response to incremental cycling exercise to test the hypothesis that ocular blood flow is relatively stable during dynamic exercise because of its autoregulatory nature. The blood flow in the inferior and superior temporal retinal arterioles (ITRA and STRA, respectively) and retinal and choroidal vessels (RCV), mean arterial pressure, and heart rate (HR) were measured at rest and during leg cycling in nine young and healthy subjects (26 ± 5 years, mean ± SD). Ocular blood flow was measured by laser speckle flowmetry. The exercise intensity was incremented by 30 W every 3 min until the subject was unable to maintain a position appropriate for measuring ocular blood flow. Blood flow data obtained during cycling exercise were categorized based on HR as follows: <100, 100-120, and >120 bpm. Blood flow in the RCV increased with the exercise intensity: by 16 ± 8, 32 ± 13, and 40 ± 19% from baseline, respectively. However, blood flow and vascular conductance in the ITRA and STRA did not change significantly with exercise. These findings demonstrate for the first time that ocular blood flow increases in the retina and choroid, but not in the arterioles, with increasing exercise intensity during dynamic exercise.

show abstract

Section: Technical Considerationsmentioning

confidence: 77%

Effects of dynamic exercise and its intensity on ocular blood flow in humans

2011

View full text Add to dashboard Cite

show abstract

“…Several studies have shown that retinal vessels react to hyperoxia by local constriction of arterioles, venules, and capillaries, thereby reducing the RBF. 8,13,15 Recently, Palkovits et al 58 have reported the effect of breathing 100% oxygen on flickerinduced vasodilation in humans. In contrast to animal studies, 59 breathing oxygen was showed to increase the flicker-induced retinal vasodilation in humans.…”

Section: Discussionmentioning

confidence: 99%

“…The autoregulating ability of the retinal blood vessels has been reported previously. [7][8][9][10][11][12][13][14][15] Several studies have demonstrated changes in retinal vessel diameter, velocity, and flow to various provocative stimuli, such as carbon dioxide (CO 2 ), O 2 and flicker in healthy 12,16,17 and diseased cohorts. [18][19][20][21] Hypoxia, a decrease in O 2 concentration, has been shown to vasodilate the retinal vessels.…”

mentioning

confidence: 99%

Intervisit Repeatability of Retinal Blood Oximetry and Total Retinal Blood Flow Under Varying Systemic Blood Gas Oxygen Saturations

Rose

Kulasekara

Hudson

2016

Invest. Ophthalmol. Vis. Sci.

View full text Add to dashboard Cite

Citation: Rose K, Kulasekara SI, Hudson C. Intervisit repeatability of retinal blood oximetry and total retinal blood flow under varying systemic blood gas oxygen saturations. Invest Ophthalmol Vis Sci. 2016;57:188-197. DOI:10.1167/iovs.15-17908 PURPOSE. The aim of the study is to validate and calibrate the Doppler spectral-domain optical coherence tomography (SD-OCT) derived total retinal blood flow (TRBF) and metabolic hyperspectral retinal camera (MHRC) derived oxygen saturation (SO 2 ) of major retinal vessels in human volunteers using a novel and exact provocation technique (RespirAct) that allows the precise control of the end-tidal partial pressure of oxygen (P ET O 2 ). Between visit repeatability of the TRBF and retinal blood SO 2 also were studied.METHODS. One eye of 11 young healthy subjects was chosen randomly for the study. Total retinal blood flow and retinal SO 2 measurements were obtained under conditions of normoxia, hyperoxia, and hypoxia. The order of hyperoxia and hypoxia was randomized between subjects. The measurements were repeated after a week interval.RESULTS. When the arterial P ET O 2 was increased from baseline (P ET O 2 ¼ 100 mm Hg) to 200 and 300 mm Hg, the TRBF significantly reduced (P ¼ 0.02) from 44.60 (68.9) to 40.28 (68.9) and 36.23 (64.6) lL/min. Lowering the arterial P ET O 2 , from baseline to 80, 60, and 50 mm Hg, TRBF significantly increased (P ¼ 0.04) from 43.17 (612.7) to 45.19 (65.5), 49.71 (613.4), and 52.89 (610.9) lL/min with simultaneous reduction in the arterial blood SO 2 content from 99.3% (65.8) to 95.6% (65.1), 89.6% (62.8), and 83.3% (63.9), respectively (P ¼ 0.00). The coefficient of repeatability (COR) of TRBF, retinal arterial, and venous blood SO 2 values are 21.8 lL/min, 18.4%, and 15.2%, respectively. CONCLUSIONS.Total retinal blood flow and retinal blood SO 2 measurements performed under safe levels of hypoxia and hyperoxia were repeatable in healthy adults over the range of SO 2 investigated.

show abstract

“…; Kisilevsky et al . ; Justesen et al . ) or increases in the

P_{{normalO}_{2}}

of solutions flowing over microvascular beds (Duling, ; Prewitt & Johnson, ; Lombard & Duling, , ; Tuma et al .…”

Section: Introductionmentioning

confidence: 99%

“…Consistent with a possible role for O 2 in the local regulation of blood flow, there is consensus that O 2 is vasoactive. Arterioles in the peripheral microcirculation constrict when exposed to increases in P O 2 produced either by increases in inspired P O 2 (Hutchins et al 1974;Zhu et al 1998;Demchenko et al 2000;Vucetic et al 2004;Sakai et al 2007;Kisilevsky et al 2008;Justesen et al 2010) or increases in the P O 2 of solutions flowing over microvascular beds (Duling, 1972;Prewitt & Johnson, 1976;Lombard & Duling, 1977, 1981Tuma et al 1977;Kontos et al 1978;Lindbom et al 1980;Proctor et al 1981;Sullivan & Johnson, 1981a,b;Proctor & Duling, 1982a,b;Jackson & Duling, 1983;Jackson, 1986Jackson, , 1987Jackson, , 1988Jackson, , 1989Jackson, , 1993Lombard et al 1986Lombard et al , 1999Lombard et al , 2004Kaul et al 1995;Hungerford et al 2000;Kunert et al 2001aKunert et al ,b, 2009Drenjancevic-Peric et al 2003Wang et al 2009;Ngo et al 2010Ngo et al , 2013. Conversely, decreases in P O 2 , produced by lowering inspired P O 2 , cause vasodilatation (see Marshall, 2000 for references).…”

Section: Introductionmentioning

confidence: 99%

Arteriolar oxygen reactivity: where is the sensor and what is the mechanism of action?

Jackson

2016

The Journal of Physiology

View full text Add to dashboard Cite

reactivity, with significant regional heterogeneity in the specific vasoconstrictor involved. Oxygen-induced vasoconstriction may serve as a protective mechanism to reduce the oxidative burden to which a tissue is exposed, a process that is superimposed on top of the local mechanisms which regulate tissue blood flow to meet a tissue's metabolic demand. showing an extravascular sensor cell and a longitudinal section through an arteriole under low and high P O2 conditions as indicated. Oxygen-sensitive enzymes in the sensor cells (generically labelled as Oxygenase), respond to elevation in the P O2 in their environment by increasing the production of a vasoconstrictor (labelled Mediator) that acts on vascular smooth muscle cells (VSM) to produce membrane depolarization, opening of L-type Ca 2+ channels and vasoconstriction. The depolarization will be conducted electrotonically along the wall of the arteriole via gap junctions to produce conducted vasoconstriction to sites distant from the initial action of the mediator. The opposite occurs when the P O2 falls from a high to a lower level. ER, endoplasmic reticulum; CysLTs, cysteinyl leukotrienes. See text for more information.

show abstract

Retinal Arteriolar and Middle Cerebral Artery Responses to Combined Hypercarbic/Hyperoxic Stimuli

Abstract: Hyperoxia reversed hypercarbia-induced vasodilation in RA in a concentration-dependent manner. Hypercarbia induced greater vasodilation in the MCA than in the RA but MCA blood velocity was unaffected by increases in P(ET)O(2).

Cited by 17 publications

References 53 publications

Effects of dynamic exercise and its intensity on ocular blood flow in humans

Effects of dynamic exercise and its intensity on ocular blood flow in humans

Intervisit Repeatability of Retinal Blood Oximetry and Total Retinal Blood Flow Under Varying Systemic Blood Gas Oxygen Saturations

Arteriolar oxygen reactivity: where is the sensor and what is the mechanism of action?

Contact Info

Product

Resources

About