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Qatar Foundation Annual Research Conference Proceedings Volume 2018 Issue 2
- Conference date: 19-20 Mar 2018
- Location: Qatar National Convention Center (QNCC), Doha, Qatar
- Volume number: 2018
- Published: 15 March 2018
81 - 82 of 82 results
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Retinal blood vessel analysis using IFLEXIS software on fundus images from the Qatar Biobank
Authors: Arnout Standaert, Patrick De Boever, Bart Elen and Rayaz A MalikRetinal examination is a diagnostic pillar in ophthalmology for the early detection of eye diseases such as retinopathy (hemorrhage/exudate) and glaucoma (optic disc abnormality). Large population-based studies have shown that retinal vessel morphological quantification may be useful in predicting the development and progression of hypertension, diabetes and cardiovascular diseases (CVD). The rationale for this is that the retinal microcirculatory bed shares similar anatomical and physiological characteristics with the coronary and cerebrovascular circulations. Therefore, quantification of retinal vessel metrics may reveal insights into the development of coronary artery and cerebrovascular disease. Indeed, retinal blood vessel analysis has gained increasing interest in recent years for predicting the development of hypertension, coronary heart disease, stroke and type II diabetes. A number of software algorithms have been used to quantify retinal vessel morphology, but they require manual input and are time- and labor-intensive. Fully automated image analysis allows objective and accurate assessment of retinal vessel parameters. VITO has developed and released IFLEXIS, software for semi-automated retinal vessel analysis, which includes algorithms to determine blood vessel widths, vessel branching and vessel network complexity, integrated in a user-friendly workflow. During the Belgian Economic Mission to Qatar in March 2015, WCM-Q, VITO and Qatar Biobank signed a Memorandum of Understanding to explore the potential of retinal analysis for the early detection of retinal vessel abnormalities in subjects attending the QBB. Fundus images from 774 people attending the Qatar Biobank contained images from healthy controls, subjects with Impaired Glucose Tolerance (IGT), Hypertension (HT) and/or Type 2 diabetes (T2DM). Here, we report the utility of IFLEXIS in a subset of 597 fundus images obtained from 574 persons which could be analyzed. The following parameters were quantified: (i) FD (fractal dimension, using the box counting method), FFD (Fourier fractal dimension) and lacunarity of the vessel network, and (ii) CRAE, CRVE (central artery/vein equivalent) and AVR (artery-to-vein ratio). Analysis revealed the following mean (range) for this population: 1.39 (1.32 - 1.53) for FD, 2.75 (1.77 - 2.98) for FFD, 1.00 (0.94 - 1.08) for lacunarity, 154.73 (93.79 - 195.67) for CRAE, 233.26 (159.67 - 307.94) for CRVE and 0.67 (0.48 - 0.93) for AVR. Statistical tests for the retinal parameters reveal interesting differences between the studied disease groups. When comparing HT with control subjects, statistically significant differences were found for the CRAE (150.05 ± 2.17 versus 157.88 ± 1.91, p = 1.02 × 10-6) and the CRVE (231.74 ± 3.60 versus 238.28 ± 2.83, p = 0.031). Comparing subjects with HT and T2DM with controls also revealed significant differences in CRAE (145.15 ± 3.62 versus 157.88 ± 1.91, p = 4.66 × 10-8) and CRVE (218.47 ± 5.16 versus 238.28 ± 2.83, p = 3.31 × 10-9). This study showed the feasibility of retinal vessel analysis of standard fundus images from the QBB using IFLEXIS. Despite the fact that the fundus images were originally not taken for this purpose, IFLEXIS software can extract novel retinal blood vessel dimensions. As blood vessel analysis has been shown to be relevant for chronic disease prediction, we propose to utilize the baseline assessment to augment the Qatar Biobank database to predict incident disease in follow-up studies. Single retinal features already appear to differentiate subjects with hypertension and/or diabetes compared to controls. We will undertake quantification of a larger image data set and will perform further data analysis to refine both the diagnostic and/or prognostic use of retinal metric analysis in the QBB population. To this end, we will combine retinal vessel metrics with demographics such as age, duration of disease and other metabolic parameters and study the association with whole genome sequence patterns in this population.
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Early predictors of incipient metabolic syndrome in an Arab population
Background. Metabolic syndrome is defined by a constellation of abnormal factors that directly increse the risk for type 2 diabetes and cardiovascular disorders. the the gulf cooperation council region the prevelance of metabolic syndrome in the population is higher than in most developed countries, with generally greater rates for women, often higher than 40%. Thus, early clinical identification of patients is important to adequately implement treatments to reduce their risk of subsequent metabolic disease. Aims/hypothesis. Therefore the aims of this study were to investigate the hypothesis that in sedentry subjects, post-prandial hyperinsulinemia, despite normal levels of glucose, is an indicator of incipient diabetes. further this lesion is associated with markers of adipose and hepatic dysfunction.Methods.Forty two apparently clinically healthy residents of Qatar were studied. After a 10-hour overnight fast, subjects underwent a detailed clinical assessment, including body composition by bioimpedance, anthropometry measurments (height, weight and BMI), and blood pressure. A liquid mixed meal was administered (200 ml of 18g proteins, 17.4g fats and 40g carbohydrates: total energetic value of 400 kcal) and blood sampling carried out prior to and 30 and 120 minutes after the meal. the study was approved by the Institutional Research Ethics Committee and all subjects provided written informed consent prior to participation.Fasting serum levels of lipids (HDL-C, LDL-C,total cholesterol and triglycrides),liver (GGT,ALP,TB,DB and albumin), plasma glucose, insulin and proinsulin were also determined. HOMA-IR (homeostasis model of assessment-insulin resistance) was calculated using the foloowing formula:(fasting insulin in mIU/L *fasting glucose in mmol/L)/22.5.Serum levels of Leptin and adiponectin were measured using human 2-site ELISAs. All inter- and intra-assay CVs were less than 10%. Results.there were no differrence in age, blood pressure and body composition between the two groups. However, 48% of this population showed hyperinsulinemia in the fasting state, as well as relative hyperglycemia, hyperinsulinemia and hyperproinsulinemia 2 hour after the meal challenge.Systemic lipids and markers of liver function were comparable between the groups. while leptin was elevated in the hyperinsulinemia group (26.1 ng/ml versus 20.9 ng/ml), this did not reach significance. However adiponectin was significantly lower in this chohort (5.8 mcg/ml versus 8.5 mcg/ml, P = 0.002).significant correlation were apparent between fasting insulin concentration and height, measures of body fat as well as muscle mass. In addition fasting insulin also correlated significant with SBP, as well as all measures of glucose and HOMA-IR. interestingly fasting insulin also correlated positively and significantly with liver enzymes. inverse, but significant, association was found between insulin with HDL-C and adiponection. Most of these relationships were lost in the postprandial state.conclusions/interpretation. Thus, these data indicate that postprandial hyperinsulinemia and decreased adiponectin levels should be considered in the plethora of the altered biochemical parameters that define the metabolic syndrome. More importantly, since these biochemical alterations occur in seemingly healthy residents, they may well be considered early biomarkers on incipient metabolic syndrome. the reasons for this lesion in a young and healthy population is likely to be the consequence of a sedentry lifestyle. Exercise and training can improve both insulin resistance and increase adiponectin and should be actively advocated for this population.
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