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Retinal Vascular Branching in Healthy and Diabetic Subjects.

ABSTRACT: To measure the effect of nonproliferative diabetic retinopathy (NPDR) on retinal branching. To compare vascular branching in healthy and diabetic subjects with established biophysical models.Vascular bifurcations in arteries and veins were imaged in 17 NPDR and 26 healthy subjects with the Indiana adaptive optics scanning laser ophthalmoscope (AOSLO). Vessel measurements were grouped according to parent vessel diameters into large (?50 ? <100 ?m) and small (?20 ? <50 ?m) sizes. Vessel diameters and bifurcation angles were measured manually. Vascular diameters were compared with predictions of Murray's law using curve fitting. For analysis of bifurcation angles, two models from Zamir were compared: one based on the power required for blood pumping, the other based on drag force between blood and vascular wall.For normal larger vessels, the exponent relating the parent and daughter branching diameters was significantly less than the value of 3 predicted by Murray's law (arteries: 2.59; veins: 1.95). In NPDR, the best-fit exponent was close to 3 for arteries but close to 2 in healthy subjects in veins, (arteries: 3.09; veins: 2.16). For both small arteries and veins, diabetics' exponent differed from healthy subjects (P < 0.01). Bifurcation angles in the healthy subjects (78° ± with a standard error (SE) of 0.9°) were not much different than in NPDR (79° ± SE 1.3°). The model based on minimizing pumping power predicted the measurements better than the one minimizing the vascular drag and lumen surface area.The relation between parent and daughter branch diameters changes in diabetes, but the branching angles do not.

SUBMITTER: Luo T

PROVIDER: S-EPMC6024667 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature

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Retinal Vascular Branching in Healthy and Diabetic Subjects.

Luo Ting T Gast Thomas J TJ Vermeer Tyler J TJ Burns Stephen A SA

Investigative ophthalmology & visual science 20170501 5

<h4>Purpose</h4>To measure the effect of nonproliferative diabetic retinopathy (NPDR) on retinal branching. To compare vascular branching in healthy and diabetic subjects with established biophysical models.<h4>Methods</h4>Vascular bifurcations in arteries and veins were imaged in 17 NPDR and 26 healthy subjects with the Indiana adaptive optics scanning laser ophthalmoscope (AOSLO). Vessel measurements were grouped according to parent vessel diameters into large (≤50 ∼ <100 μm) and small (≤20 ∼ ...[more]

PMID: 28525557

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Project description:BackgroundThis study was designed to determine the glycemic indices of five commonly used varieties of dates in healthy subjects and their effects on postprandial glucose excursions in individuals with type 2 diabetes mellitus.MethodsComposition analysis was carried out for five types of dates (Tamer stage). The weights of the flesh of the dates equivalent to 50 g of available carbohydrates were calculated. The study subjects were thirteen healthy volunteers with a mean (± SD) age of 40.2 ± 6.7 years and ten participants with type 2 diabetes mellitus (controlled on lifestyle measures and/or metformin) with a mean HbA1c (± SD) of 6.6 ± (0.7%) and a mean age (± SD) of 40.8 ± 5.7 years. Each subject was tested on eight separate days with 50 g of glucose (on 3 occasions) and 50 g equivalent of available carbohydrates from the 5 varieties of date (each on one occasion). Capillary glucose was measured in the healthy subjects at 0, 15, 30, 45, 60, 90 and 120 min and for the diabetics at 0, 30, 60, 90, 120, 150 and 180 min. The glycemic indices were determined as ratios of the incremental areas under the response curves for the dates compared to glucose. Statistical analyses were performed using the Mann-Whitney U test and repeated measures analysis of variance.ResultsMean glycemic indices ± SEM of the dates for the healthy individuals were 54.0 ± 6.1, 53.5 ± 8.6, 46.3 ± 7.1, 49.1 ± 3.6 and 55.1 ± 7.7 for Fara'd, Lulu, Bo ma'an, Dabbas and Khalas, respectively. Corresponding values for those with type 2 diabetes were very similar (46.1 ± 6.2, 43.8 ± 7.7, 51.8 ± 6.9, 50.2 ± 3.9 and 53.0 ± 6.0). There were no statistically significant differences in the GIs between the control and the diabetic groups for the five types of dates, nor were there statistically significant differences among the dates' GIs (df = 4, F = 0.365, p = 0.83).ConclusionThe results show low glycemic indices for the five types of dates included in the study and that their consumption by diabetic individuals does not result in significant postprandial glucose excursions. These findings point to the potential benefits of dates for diabetic subjects when used in a healthy balanced diet.Trial registration numberClinicalTrials.gov NCT01307904.

Dataset Information

Retinal Vascular Branching in Healthy and Diabetic Subjects.

Publications

Retinal Vascular Branching in Healthy and Diabetic Subjects.

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