Myogenic Response Reduction by High Blood Glucose Levels in Human Retinal Arterioles

Blum, Marcus; Brandel, Catherine L.; M⊘ller, U.

doi:10.1177/112067210501500109

Cited by 17 publications

(12 citation statements)

References 18 publications

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“…Consequently, a change in diameter is not necessarily accompanied by a change in blood flow. In addition to this, although the increase in MAP of 22–23% and the contraction observed in the retinal arterioles in this study were comparable with those found in other studies (Blum et al. 1999, 2005), we were unable to show an effect of acute hyperglycaemia on the response of retinal arteriole diameter after an increase in systemic blood pressure.…”

Section: Discussionsupporting

confidence: 72%

“…1996). A recent study showed that acute hyperglycaemia secondary to an oral glucose load diminishes the response of retinal arteriole diameter nearly threefold after an increase in mean systemic arterial blood pressure (Blum et al. 2005).…”

Section: Discussionmentioning

confidence: 99%

“…1980; Bursell et al. 1996), and results from a recent study in normal persons suggest that a high oral intake of glucose reduces pressure autoregulation in retinal arterioles (Blum et al. 2005).…”

Section: Introductionmentioning

confidence: 99%

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Response of retinal arteriole diameter to increased blood pressure during acute hyperglycaemia

Jeppesen

Knudsen

Poulsen

et al. 2006

Acta Ophthalmologica Scandinavica

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ABSTRACT.Purpose: To study retinal response in terms of arteriole diameter and retinal thickness secondary to an increase in arterial blood pressure during acute hyperglycaemia. Methods: In a randomized, double-blinded, cross-over study, nine healthy persons were subjected to clamping of blood glucose to either 5 mmol ⁄ l or 15 mmol ⁄ l using somatostatin to control endogenous insulin secretion. The response of retinal arterioles in terms of diameter as determined with the retinal vessel analyser (RVA) and retinal thickness as assessed by optical coherence tomography (OCT) were measured after an increase in arterial blood pressure induced by isometric exercise. Arterial feeding pressure in the eye was assessed from the ophthalmic artery pressure and pulse amplitude measured by ophthalmodynamometry. Results: Isometric exercise induced a significant increase in mean arterial blood pressure and a significant contraction of the retinal arterioles. An acute increase in blood glucose from 5 mmol ⁄ l to 15 mmol ⁄ l did not affect either the diameter of retinal vessels or retinal thickness. Conclusions: Acute hyperglycaemia per se does not change isometric exerciseinduced retinal arteriolar contraction. Metabolic factors other than blood glucose are suspected to be involved in the impairment of retinal autoregulation as seen in hyperglycaemia induced by oral glucose intake.

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Section: Discussionsupporting

confidence: 72%

Section: Discussionmentioning

confidence: 99%

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Response of retinal arteriole diameter to increased blood pressure during acute hyperglycaemia

Jeppesen

Knudsen

Poulsen

et al. 2006

Acta Ophthalmologica Scandinavica

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“…The coupling between metabolism and retinal blood flow have not been elucidated in detail, and especially the influence of the glucose metabolism on retinal blood flow is important since this may help in understanding the development of diabetic retinopathy. It has been shown that hyperglycemia may cause retinal hyperperfusion (3,7), and in normal persons a high peroral intake of glucose has been shown to reduce retinal autoregulation (6). However, hyperglycemia may also induce other metabolic changes with an effect on retinal blood flow, such as increasing the release of insulin, which may induce changes in retinal blood flow (23,28).…”

mentioning

confidence: 98%

Acute hyperinsulinemia increases the contraction of retinal arterioles induced by elevated blood pressure

Jeppesen

Knudsen

Poulsen

et al. 2013

American Journal of Physiology-Heart and Circulatory Physiology

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Diabetic retinopathy is accompanied by disturbances in retinal blood flow, which is assumed to be related to the diabetic metabolic dysregulation. It has previously been shown that normoinsulinemic hyperglycemia has no effect on the diameter of retinal arterioles at rest and during an increase in the arterial blood pressure induced by isometric exercise. However, the influence of hyperinsulinemia on this response has not been studied in detail. In seven normal persons, the diameter response of retinal arterioles to an increased blood pressure induced by isometric exercise, to stimulation with flickering light, and to the combination of these stimuli was studied during euglycemic normoinsulinemia (protocol N) on one examination day, and euglycemic hyperinsulinemia (protocol H) on another examination day. Isometric exercise induced significant contraction of retinal arterioles at all examinations, but during a repeated examination the diameter response was significantly reduced in the test persons following the N protocol and increased in the persons following the H protocol. Flicker stimulation induced a significant dilatation of retinal arterioles at all examinations, and the response was significantly higher during a repeated examination, irrespective of the insulin level. Repeated exposure to isometric exercise reduces contraction, whereas repeated exposure to flickering light increases dilatation of retinal arterioles in vivo. Hyperinsulinemia increases contraction of retinal arterioles induced by isometric exercise.

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“…Measurements can be started by a mouse click, and the diameter of the column of red blood cells was measured by the contrast from wall to wall, which is defined as vessel width. The mean vessel diameter during phase I was used as a baseline to calculate the resulting percentage change in vessel diameter [3, 9, 10]. …”

Section: Methodsmentioning

confidence: 99%

Improved Metabolic Control Results in Better Myogenic Response of Retinal Arterioles in Patients with Diabetes Mellitus Type 1

Blum

Kloos²,

Gunther³

et al. 2008

Ophthalmologica

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Aims: The retina is protected against high blood pressure by the myogenic constriction of arterioles (the Bayliss effect). Hyperglycemia impairs this retinal autoregulation by endothelial dysfunction. The purpose of this prospective pilot study was to test whether improved metabolic control results in a measurable effect on the myogenic response of human retinal arterioles to acute increases in blood pressure. Methods: The Bayliss effect was measured in 25 patients with diabetes mellitus by the Retinal Vessel Analyzer (RVA), both before and after participation in a treatment and teaching program for intensified insulin therapy with the goal of improved metabolic control. After 12 months, 17 subjects still fulfilled the inclusion criteria and underwent an identical measurement. The Wilcoxon test was used for statistical analysis. Results: During the first session, a rise in mean arterial pressure (MAP) of 20.2 ± 8.6 mm Hg was followed by an arterial vasoconstriction of –3.2 ± 2.9%. The educational program resulted in a significant drop in Hb_A1c levels (9.4 ± 1.9 vs. 6.9 ± 0.98%). Eight subjects did not meet the inclusion criteria after 12 months. Seventeen subjects were remeasured and a rise in blood pressure of 19.5 ± 9.9 mm Hg in the second session was associated with a significantly improved arterial vasoconstriction of –5.9 ± 2.7% (session I vs. session II, p = 0.006). Conclusion: The myogenic response of the arterial wall in human retinal arterioles was significantly improved by the therapeutic intervention.

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Myogenic Response Reduction by High Blood Glucose Levels in Human Retinal Arterioles

Abstract: The myogenic response of the arterial wall in human retinal arterioles was significantly reduced during acute rise of blood glucose levels.

Cited by 17 publications

References 18 publications

Response of retinal arteriole diameter to increased blood pressure during acute hyperglycaemia

Response of retinal arteriole diameter to increased blood pressure during acute hyperglycaemia

Acute hyperinsulinemia increases the contraction of retinal arterioles induced by elevated blood pressure

Improved Metabolic Control Results in Better Myogenic Response of Retinal Arterioles in Patients with Diabetes Mellitus Type 1

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