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

https://arctichealth.org/en/permalink/ahliterature107100
Source
Am J Physiol Heart Circ Physiol. 2013 Dec 1;305(11):H1600-4
Publication Type
Article
Date
Dec-1-2013
Author
Peter Jeppesen
Søren Tang Knudsen
Per Løgstrup Poulsen
Anders Hessellund
Ole Schmitz
Toke Bek
Author Affiliation
Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark; and.
Source
Am J Physiol Heart Circ Physiol. 2013 Dec 1;305(11):H1600-4
Date
Dec-1-2013
Language
English
Publication Type
Article
Keywords
Acute Disease
Adult
Analysis of Variance
Arterial Pressure
Arterioles - physiopathology
Blood Glucose - metabolism
Cross-Over Studies
Denmark
Exercise
Homeostasis
Humans
Hyperinsulinism - blood - physiopathology
Insulin - blood
Isometric Contraction
Male
Photic Stimulation
Retinal Vessels - physiopathology
Time Factors
Vasoconstriction
Young Adult
Abstract
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.
PubMed ID
24056905 View in PubMed
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Relative magnitude of vascular reactivity in the major arterioles of the retina.

https://arctichealth.org/en/permalink/ahliterature129511
Source
Microvasc Res. 2012 Mar;83(2):200-4
Publication Type
Article
Date
Mar-2012
Author
Mitra Sehi
Edmund Tsui
Richard Cheng
Jennifer Wan
Tien Wong
Stephanie Dorner
Joseph Fisher
Christopher Hudson
Author Affiliation
Bascom Palmer Eye Institute, Department of Ophthalmology, Miller School of Medicine, University of Miami, Palm Beach Gardens, FL, USA.
Source
Microvasc Res. 2012 Mar;83(2):200-4
Date
Mar-2012
Language
English
Publication Type
Article
Keywords
Adult
Arterioles - physiopathology
Blood Flow Velocity
Female
Hemodynamics
Humans
Hypercapnia - physiopathology
Hyperoxia - physiopathology
Laser-Doppler Flowmetry
Male
Microcirculation
Ontario
Prospective Studies
Regional Blood Flow
Retinal Vessels - physiopathology
Time Factors
Vasoconstriction
Vasodilation
Young Adult
Abstract
The relative magnitude of vascular reactivity to inhaled gas stimuli in the major retinal arterioles has not been systematically investigated. The purpose of this study was to compare the magnitude of retinal vascular reactivity in response to inhaled gas provocation at equivalent measurement sites in the superior-, and inferior-, temporal retinal arterioles (STA, ITA). One randomly selected eye of each of 17 healthy volunteers (age 24.4 ± 4.7) was prospectively enrolled. Volunteers were connected to a sequential gas delivery circuit and a computer-controlled gas blender (RespirActâ„¢, Thornhill Research Inc., Canada) and underwent an isocapnic hyperoxic challenge i.e. P(ET)O(2) of 500 mm Hg with P(ET)CO(2) maintained at 38 mm Hg during baseline and hyperoxia. Four retinal hemodynamic measurements were acquired using bi-directional laser Doppler velocimetry and simultaneous vessel densitometry (Canon Laser Blood Flowmeter, CLBF-100, Japan) at equivalent positions on the STA and ITA. Statistical analysis was performed using linear mixed-effect models. During the hyperoxic phase, the vessel diameter (STA p=0.004; ITA p=0.003), blood velocity (STA p0.05). The magnitude of retinal arteriolar vascular reactivity in response to isocapnic hyperoxic inhaled gas challenge was not significantly different between the STA and ITA. However, the correlation analysis did not reveal a significant relationship between the percentage changes in diameter, velocity and flow of the STA and ITA and did not demonstrate equal responses from the STA and ITA to gas provocation.
PubMed ID
22100560 View in PubMed
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Renal resistance and long-term blood pressure in individuals genetically predisposed for essential hypertension: 10-year follow-up of the Danish Hypertension Prevention Project.

https://arctichealth.org/en/permalink/ahliterature284806
Source
J Hypertens. 2016 Jun;34(6):1170-7
Publication Type
Article
Date
Jun-2016
Author
Niels H Buus
Michael J Mulvany
Hans Eiskjær
Kent L Christensen
Karin Skov
Source
J Hypertens. 2016 Jun;34(6):1170-7
Date
Jun-2016
Language
English
Publication Type
Article
Keywords
Adult
Angiotensin Receptor Antagonists - therapeutic use
Antihypertensive Agents - therapeutic use
Arterioles - physiopathology
Benzimidazoles - therapeutic use
Blood Pressure - drug effects
Blood Pressure Monitoring, Ambulatory
Denmark
Female
Follow-Up Studies
Humans
Hypertension - genetics - physiopathology - prevention & control
Male
Renin-Angiotensin System - drug effects
Tetrazoles - therapeutic use
Time Factors
Vascular Resistance - drug effects
Abstract
Young individuals genetically predisposed for essential hypertension have increased renal vascular resistance. We evaluated whether 1 year of angiotensin II receptor blockade decreases afferent arteriolar resistance (RA) and induces a sustained blood pressure (BP) reduction during a 10-year follow-up period in offspring of parents both diagnosed with essential hypertension.
Based on renal plasma flow (p-aminohippurate clearance) and glomerular filtration rate (Cr-EDTA clearance) RA was calculated according to the model originally established by Gomez. Following baseline measurements, the participants (n?=?110, mean age 30 years) were randomly allocated to 12 months of treatment with either candesartan or placebo followed by repetition of measurements and withdrawal of medication. Four-hour ambulatory BP (ABP) was recorded at baseline, by end of active treatment and after 6 months, 1, 2, 3, 5, and 10 years. ABP was analyzed according to RA achieved at the end of active treatment.
Candesartan reduced RA by 14% (P?
PubMed ID
27054529 View in PubMed
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Retinal and cerebral microvascular signs and diabetes: the age, gene/environment susceptibility-Reykjavik study.

https://arctichealth.org/en/permalink/ahliterature93473
Source
Diabetes. 2008 Jun;57(6):1645-50
Publication Type
Article
Date
Jun-2008
Author
Qiu Chengxuan
Cotch Mary Frances
Sigurdsson Sigurdur
Garcia Melissa
Klein Ronald
Jonasson Fridbert
Klein Barbara E K
Eiriksdottir Gudny
Harris Tamara B
van Buchem Mark A
Gudnason Vilmundur
Launer Lenore J
Author Affiliation
Laboratory of Epidemiology, Demography, and Biometry, National Institute on Aging, National Institutes of Health (NIH), Bethesda, Maryland 20892, USA.
Source
Diabetes. 2008 Jun;57(6):1645-50
Date
Jun-2008
Language
English
Publication Type
Article
Keywords
Aged
Aged, 80 and over
Arterioles - physiopathology
Cerebral Hemorrhage - epidemiology - pathology
Cerebrovascular Circulation - physiology
Diabetes Mellitus - genetics - physiopathology
Environment
Female
Genetic Predisposition to Disease
Humans
Iceland
Magnetic Resonance Imaging
Male
Microcirculation - physiology
Middle Aged
Retina - physiopathology
Retinal Vessels - physiopathology
Venules - physiopathology
Abstract
OBJECTIVE: Diabetes increases the risk for microvascular disease. The retina and the brain both have intricate microvascular systems that are developmentally similar. We sought to examine whether microvascular lesions in the retina and in the brain are associated and whether this association differs among people with and without diabetes. RESEARCH DESIGN AND METHODS: The analysis included 4,218 participants of the Icelandic population-based Age, Gene/Environment Susceptibility-Reykjavik Study who were born in 1907-1935 and who were previously followed as a part of the Reykjavik Study. Retinal focal arteriolar narrowing, arteriovenous (AV) nicking, and microaneurysms/hemorrhages were evaluated on digital retinal images of both eyes. Cerebral microbleeds (CMBs) were evaluated from magnetic resonance images. Data were analyzed with logistic and multinomial logistic regression models controlling for demographics, major cardiovascular risk factors, cerebral infarcts, and white matter lesions. RESULTS: Evidence of brain microbleeds was found in 485 (11.5%) people, including 192 with multiple (>or=2) microbleeds. Subjects with signs of retinal microvascular lesions were at a significantly increased likelihood for having multiple CMBs. People with diabetes in combination with the presence of either retinal AV nicking (odds ratio [OR] 2.47 [95% CI 1.42-4.31]) or retinal microaneurysms/hemorrhages (2.28 [1.24-4.18]) were significantly more likely to have multiple CMBs. CONCLUSIONS: Retinal microvascular abnormalities and brain microbleeds may occur together in older adults. People with both diabetes and signs of retinal microvascular lesions (AV nicking and microaneurysms/hemorrhages) are more likely to have multiple microbleeds in the brain. Microvascular disease in diabetes extends to the brain.
PubMed ID
18332097 View in PubMed
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