Retinal Vessel Diameter Research Articles

Diphlorethohydroxycarmalol Isolated from Ishige okamurae Represses High Glucose-Induced Angiogenesis In Vitro and In Vivo.

Diabetes mellitus causes abnormalities of angiogenesis leading to vascular dysfunction and serious pathologies. Diphlorethohydroxycarmalol (DPHC), which is isolated from Ishige okamurae, is well known for its bioactivities, including antihyperglycemic and protective functions against diabetes-related pathologies. In the present study, the inhibitory effect of DPHC on high glucose-induced angiogenesis was investigated on the human vascular endothelial cell line EA.hy926. DPHC inhibited the cell proliferation, cell migration, and tube formation in cells exposed to 30 mM of glucose to induce angiogenesis. Furthermore, the effect of DPHC against high glucose-induced angiogenesis was evaluated in zebrafish embryos. The treatment of embryos with DPHC suppressed high glucose-induced dilation in the retinal vessel diameter and vessel formation. Moreover, DPHC could inhibit high glucose-induced vascular endothelial growth factor receptor 2 (VEGFR-2) expression and its downstream signaling cascade. Overall, these findings suggest that DPHC is actively involved in the suppression of high glucose-induced angiogenesis. Hence, DPHC is a potential agent for the development of therapeutics against angiogenesis induced by diabetes.

Non-invasive evaluation of neurovascular coupling in the murine retina by dynamic retinal vessel analysis.

BackgroundImpairment of neurovascular coupling (NVC) was recently reported in the context of subarachnoid hemorrhage and may correlate with disease severity and outcome. However, previous techniques to evaluate NVC required invasive procedures. Retinal vessels may represent an alternative option for non-invasive assessment of NVC.MethodsA prototype of an adapted retinal vessel analyzer was used to assess retinal vessel diameter in mice. Dynamic vessel analysis (DVA) included an application of monochromatic flicker light impulses in predefined frequencies for evaluating NVC. All retinae were harvested after DVA and electroretinograms were performed.ResultsA total of 104 retinal scans were conducted in 21 male mice (90 scans). Quantitative arterial recordings were feasible only in a minority of animals, showing an emphasized reaction to flicker light impulses (8 mice; 14 scans). A characteristic venous response to flicker light, however, could observed in the majority of animals. Repeated measurements resulted in a significant decrease of baseline venous diameter (7 mice; 7 scans, p < 0.05). Ex-vivo electroretinograms, performed after in-vivo DVA, demonstrated a significant reduction of transretinal signaling in animals with repeated DVA (n = 6, p < 0.001).ConclusionsTo the best of our knowledge, this is the first non-invasive study assessing murine retinal vessel response to flicker light with characteristic changes in NVC. The imaging system can be used for basic research and enables the investigation of retinal vessel dimension and function in control mice and genetically modified animals.

Retinal vessel oxygen saturation and vessel diameter in healthy individuals during high-altitude exposure.

To assess changes of retinal vessel oxygen saturation and vessel diameter in healthy individuals during high-altitude exposure. Retinal oxygen saturation and vessel diameter were obtained at sea level (SL, 40m) and high altitude (HA, 3681m) on 17 healthy individuals from Beijing (six males, 28.06±8.06years) using Oxymap T1 and then compared with 21 residents from Yushu (10 males, 28.63±6.00years). Systemic and ocular parameters were also measured before and after high-altitude exposure. Data were presented as mean±SD and analysed using paired and independent Student t-test with significance accepted at p<0.05. Short-term high-altitude exposure of Beijing Group significantly affected all the systemic and ocular parameters, as well as retinal oxygen saturation and vessel diameter ranging from overall quadrant to different quadrants, other than retinal venous oxygen saturation and retinal arterial diameter. However, these changes were not evident in those permanently living at HA. Pearson's correlation analysis revealed correlations between retinal oxygen saturation and systemic and ocular parameters (all p<0.05). The multivariate linear regression analysis indicated that retinal arterial oxygen saturation was significantly associated with arterial peripheral arterial oxygen saturation (SpO2 ) and subfoveal choroidal thickness. Short-term exposure to HA induces retinal microcirculation disturbance and auto-regulatory response in healthy individuals, which is probably attributed to arterial SpO2 and endothelial dysfunction under hypoxic conditions.

Retinal Vessel Diameter Changes in Relation to Dark Adaptation and Acute Hyperglycemia.

The purpose of this experimental clinical study was to assess the effects of dark adaptation and acute changes in glycemia on retinal vessel diameters in men. The study included 14 patients (mean age 63 years, range 48–74 years) with type 2 diabetes mellitus and minimal or no diabetic retinopathy. Retinal vessel diameters were assessed using infrared photography before and after dark adaptation, first while fasting and then at peak hyperglycemia during an oral glucose tolerance test (OGTT). Dark adaptation was accompanied by retinal vasodilatation, both during fasting (mean glycemia 7.6 ± 1.7 mM) and postprandial hyperglycemia (15.7 ± 4.2 mM). When fasting, the increase in vein diameter during dark adaptation was 2.0% after 20 min (P=0.018) and 2.9% after 40 min (P=0.010). When subjects were hyperglycemic, the increase during dark adaptation was 2.8% for retinal vein diameters (P=0.027) and 2.0% for retinal artery diameters after 20 min (P=0.002) and 1.7% for retinal artery diameters after 40 min (P=0.022). For identical conditions of light/dark adaptation, retinal vessels were dilated when subjects were fasting compared to postprandial hyperglycemia. Thus, darkness and fasting were both associated with retinal vasodilation in this short-term experiment in patients with type 2 diabetes. Future studies should determine whether both the stimuli of vasodilation lead to retinal hyperperfusion, which would support that they may be involved in the aggravation of diabetic retinopathy.

Relationship between the changes of high-sensitivity C-reactive protein and retinal vessel diameter in the middle-aged and elderly: the Kailuan Study

Objective To investigate the relationship between high-sensitivity C-reactive protein (hsCRP) and retinal vascular diameter. Methods This study was a cross-sectional study, the population was from the Kailuan study (clinical trial research registration NO.: ChiCTR-TNC-1100 1489) in 2012—2013 (age≥40 years). All the people was checked by cardiovascular and epidemiological examination, of which 3 447 people had an analytical results of fundus color photography.The retinal vascular diameter was analyzed by software.Take the value of hsCRP 1% to 99% points and 3 363 people were finally included in the statistical analysis.The mean age of 3 363 people (male 1 880, female 1 483) was 56.69±10.10 years old.The correlation between hsCRP and central retinal artery equivalent(CRAE), central retinal vein equivalent (CRVE), arteriovenous ratio(AVR) were evaluated by Spearman correlation coefficient.Multivariate linear regression analysis was used to futher analyze the association between hsCRP and retinal fundus diameter parameters. Results The median value of hsCRP was 1.10(0.50, 2.21)mmo/L, CRAE was (174.16±24.36)μm, CRVE was (282.70±26.32)μm, AVR was 0.62±0.09.Spearman correlation analysis showed that hsCRP was positively correlated with CRVE (r=0.052, P=0.003) and negatively correlated with AVR (r=-0.052, P=0.002). The non-normal variables hsCRP were transformed into continuous variables lghsCRP, and CRAE, CRVE and AVR were used for multivariate linear regression analysis.After a number of factors were gradually corrected, the results showed that association between lghsCRP and CRVE (β=3.428) or AVR (β=-0.006) was statistically significant (P<0.05). LghsCRP was a risk factor for CRVE both in men and women after the calculation of gender stratification. Conclusions CRVE increased and AVR decreased with the increase of hsCRP.The changes of retinal vascular diameter may be associated with hsCRP as a marker to predict cardiovascular and cerebrovascular disease. Key words: Central retinal artery equivalent; Central retinal vein equivalent; High-sensitivity C-reactive protein

Changes in Retinal Vascular Caliber after Intravitreal Aflibercept Treatment for Diabetic Macular Oedema

Diabetic retinopathy is characterised by impaired retinal vascular autoregulation with signs of early retinal hyperperfusion and subsequent capillary drop out and peripheral ischemia. Initial retinal vascular dilation indicates disease progression and subsequent constriction signals a proliferative state. In this pilot study, we examined the effect of intravitreal aflibercept on retinal vessel diameter in patients with diabetic macular oedema. Twelve eyes of nine treatment-naive patients with diabetic macular oedema were examined during the first three months of treatment with aflibercept. The calibers of retinal arteries and veins and the central retinal arterial and vein equivalent were registered over the course of treatment. The evolution of the diabetic macular oedema was also registered and correlated to the retinal vascular caliber. During treatment, there was a significant reduction in the diameter of retinal arteries as well as in the central retinal arterial equivalent. The calibers of the retinal veins were also reduced, but not significantly. Macular oedema was significantly reduced, which however did not correlate with the vascular caliber changes. This pilot study demonstrates for the first time a possible significant reduction in retinal arterial caliber under aflibercept treatment for diabetic macular oedema. Further studies are needed to verify whether this response to intravitreal anti-VEGF treatment also signifies an improvement in retinal vascular homeostasis.

Retinal Arteriolar Narrowing in Young Adults With Glaucomatous Optic Disc.

Glaucomatous optic disc (GOD) might represent various subclinical processes. However, whether the presence of GOD is related to vascular processes is less clear. This study aimed to assess the retinal vessel diameter, as surrogate markers of vascular regulation, in healthy young adults with GOD compared with normal. This was a clinic-based case-control study of 54 participants, aged between 18 and 30 years. We included patients with GOD (confirmed with slit-lamp and optical coherence tomography examination having cup-to-disc ratio ≥0.5), intraocular pressure ≤21 mm Hg, no history of hypertension, cardiovascular and kidney disease, anemia, diabetes mellitus, and spherical correction of ≤-1.5 D. Controls were healthy subjects with similar criteria but no sign of GOD. Retinal vessel diameters were measured using semiautomated program [Singapore I Vessel Assessment (SIVA) version 4.0] and expressed as central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent. The mean CRAE was significantly narrower in patients with GOD than controls (110.6±12.16 vs. 118.6±12.17; P=0.019). Central retinal venular equivalent was not significantly different. A CRAE narrower than 107.1 μm was significantly associated with GOD (odds ratio, 8.59; 95% confidence interval, 1.68-43.9; P<0.001) compared with controls. Retinal arterioles were narrower in young adults with GOD compared with normal, suggesting that the presence of GOD might be associated with subclinical changes in retinal vascularization even in the absence of increased intraocular pressure. However, the clinical significance of these findings deserves further studies.

P1557Association of obesity and hypertension with retinal vessel diameters, arterial stiffness and physical fitness in Swiss primary school children

P1557Association of obesity and hypertension with retinal vessel diameters, arterial stiffness and physical fitness in Swiss primary school children

Oxygen-Induced Retinopathy and Choroidopathy: In Vivo Longitudinal Observation of Vascular Changes Using OCTA.

The purpose of this study was to assess the retinal and choroidal vasculatures of an oxygen-induced retinopathy (OIR) rat model using optical coherence tomography angiography (OCTA) as well as to verify the performance of OCTA for visualizing in vivo vascular alterations, longitudinally and quantitatively. To induce OIR, Sprague Dawley rat pups were incubated in an 80% oxygen chamber from postnatal day 1 (P1) to P11 and returned to room air. OCTA imaging was performed in six eyes at P15, P18, P21, and P24. All eyes were imaged with ex vivo retinal flat mount immunofluorescence microscopy for comparison with OCTA. The areas of the neovascular tufts, retinal vessel tortuosities and diameters, and vessel densities of different retinal and choroidal layers were quantified. The neovascular tufts were observed in two OIR eyes. The tuft areas decreased spontaneously from P18 to P24. The increase in arterial tortuosity and venous dilation were observed in the OIR eyes at P15 and P18. The retardation of vascular developments was observed in the deep vascular plexus and the choroidal layer in the OIR group while the superficial vascular plexus did not show developmental delay. This study demonstrates an application of OCTA for quantitative and longitudinal studies on in vivo vascular alterations, including neovascular tufts, increase in arterial tortuosity, venous dilation, and developmental delay in the OIR rat model.

Effects of different endurance exercise modalities on retinal vessel diameters in unipolar depression

BackgroundPsychiatric disorders are associated with a high prevalence of cardiovascular disease. Regular exercise is known to reduce depressive symptoms and improve vascular function, in turn lowering cardiovascular risk. We aimed to investigate the effects of different exercise modalities on retinal vessel diameters as a microvascular biomarker and depression severity index in patients suffering from unipolar depression. Methods23 patients (female: 19, male: 4, age: 36.7, Beck-Depression-Inventory-II (BDI-II) score: 30.7) were enrolled in this two-armed randomized controlled trial. Static vessel analysis was performed to obtain central retinal arteriolar (CRAE) and venular (CRVE) diameter equivalents and the arterio-venous diameter ratio (AVR). Maximal bicycle ergometer exercise testing yielded maximal fitness parameters. Patients were assigned to either high intensity low volume (HILV) or moderate continuous aerobic training (MCT). Both intervention groups trained three times a week during a 4-week intervention period. ResultsModerate interaction effects were found for AVR (ɳp2 = 0.12) whereby HILV showed a larger increase in AVR (HILV: pre: 0.89 (0.04), post: 0.91 (0.04), SMD = −0.50) compared to MCT (MCT: pre: 0.85 (0.06), post: 0.86 (0.05), SMD = −0.18). Parallel group trials revealed a 67% possibly beneficial effect of HILV over MCT. Moderate interaction effects on depression severity reduction (ɳp2 = 0.06) were found, whereby the effect size was slightly larger in MCT. ConclusionBoth exercise interventions improved AVR as well as BDI-II. HILV may be more effective in improving cerebrovascular health. The exercise-induced effects on retinal vessel diameter changes were relatively small and the clinical relevance remains to be investigated in larger and longer-term exercise trials.

Experimental Characterization and Correlation of Mayer Waves in Retinal Vessel Diameter and Arterial Blood Pressure.

Retinal vessels show various biological temporal variations that can impact diagnosis using a static vessel analysis. In this study, Mayer waves in the retinal vessel diameter and arterial blood pressure (BP) signals were characterized, and the temporal correlation between these two modalities was investigated. The arterial and venous vessel diameters and arterial BP were recorded simultaneously on human subjects. The obtained vessel diameters showed vasomotion amplitudes over time. The vessel diameter and BP signals contained multiple signals in the frequency domain and varied over time. The signal characteristics were similar within the measurements. The BP and arterial and venous vessel diameters were correlated. The highest correlation values between the signals were observed for shifts of 1 or 0 periods. The spectrum and amplitudes of the Mayer waves showed a high variability. The Mayer waves in the retinal vessel diameters showed the same characteristics as those in the arterial BP. A temporal dependency between the oscillations in the arterial BP and retinal vessel diameters was shown.

The short-term effect of acupuncture on different ocular blood flow parameters in patients with primary open-angle glaucoma: a randomized, clinical study.

IntroductionTo investigate the effect of acupuncture on different ocular blood flow (OBF) parameters in patients with primary open-angle glaucoma (POAG).Patients and methodsIn a prospective, randomized study, 56 POAG patients were randomly assigned either to an eye-specific acupuncture (group I, n=28) or to an eye-unspecific acupuncture treatment (group II, n=28). Blood flow parameters were measured before and 10 minutes after treatment. Parapapillary retinal blood flow was determined by the Heidelberg retina flowmeter. Retinal vessel diameters were measured by the dynamic vessel analyzer. Pulsatile ocular blood flow, ocular pulse amplitude, and IOP were investigated by the Langham OBF system. Systemic blood pressure was obtained additionally.ResultsPulsatile ocular blood flow increased significantly after the eye-specific acupuncture treatment from 5.6±4.3 to 6.7±4.9 µL/min (P=0.014). There was no significant change in parapapillary retinal blood flow, retinal vessel diameter, systemic blood pressure, or IOP after treatment in neither of the two groups.ConclusionAn eye-specific acupuncture treatment may affect OBF in POAG patients.

Association of cardiorespiratory fitness with retinal vessel diameters as a biomarker of cardiovascular risk

ObjectiveWe aimed to investigate the association of retinal microvascular health with cardiorespiratory fitness (VO2peak) and cardiovascular risk factors. MethodsIn a population of 260 obesity-enriched participants we investigated the association of retinal vessel diameters with cardiorespiratory fitness (CRF), body mass index (BMI) and blood pressure (BP). Retinal vessel imaging was performed by use of a fundus camera and a semi-automated processing software, calculating the central retinal arteriolar (CRAE) and venular equivalent (CRVE) as well as the arteriolar-to-venular diameter ratio (AVR). ResultsParticipants had a mean age of 45.8 ± 12.5 years and a BMI of 35.8 ± 6.8 kg/m2. 45% of patients were diagnosed with hypertension, 26% with diabetes and 30% with dyslipidemia. Increasing VO2peak was independently associated with lower CRVE (β = −0.600; CI −1.141, −0.060; p = 0.030). Higher BMI and mean arterial pressure were independently associated with narrower CRAE (β = −0.492; CI −0.909, −0.076; p = 0.021 and β = −0.268; CI −0.471, −0.066; p = 0.009, respectively) and lower AVR (β = −0.002; CI −0.003, −0.000; p = 0.026 and β = −0.001; CI −0.002, −0.000; p = 0.001, respectively). ConclusionsHigher cardiorespiratory fitness is associated with beneficial retinal microvascular health. Higher BMI and BP were associated with an impairment of retinal microvascular health. Exercise is known for its potential to improve body composition and reduce BP but may also prove to be an efficient therapy to counteract small vessel disease in cardiometabolic disease.

Association between blood pressure and retinal arteriolar and venular diameters in Chinese early adolescent children, and whether the association has gender difference: a cross-sectional study

BackgroundTo establish the independent association between blood pressure (BP) and retinal vascular caliber, especially the retinal venular caliber, in a population of 12-year-old Chinese children.MethodsWe have examined 1501 students in the 7th grade with mean age of 12.7 years. A non-mydriatic fundus camera (Canon CR-2, Tokyo, Japan) was used to capture 450 fundus images of the right eyes. Retinal vascular caliber was measured using a computer-based program (IVAN). BP was measured using an automated sphygmomanometer (HEM-907, Omron, Kyoto, Japan).ResultsThe mean retinal arteriolar caliber was 145.3 μm (95% confidence interval [CI], 110.6–189.6 μm) and the mean venular caliber was 212.7 μm (95% CI, 170.6–271.3 μm). After controlling for age, sex, axial length, BMI, waist, spherical equivalent, birth weight, gestational age and fellow retinal vessel caliber, children in the highest quartile of BP had significantly narrower retinal arteriolar caliber than those with lower quartiles (P for trend< 0.05). Each 10-mmHg increase in BP was associated with narrowing of the retinal arterioles by 3.00 μm (multivariable-adjusted P < 0.001), and the results were consist in three BP measurements. The association between BP measures and retinal venular caliber did not persist after adjusting for fellow arteriolar caliber. And there was no significant interaction between BP and sex, age, BMI, and birth status.ConclusionsIn a large population of adolescent Chinese children, higher BP was found to be associated with narrower retinal arterioles, but not with retinal venules. Sex and other confounding factors had no effect on the relationship of BP and retinal vessel diameter.

Obesity, Blood Pressure, and Retinal Vessels: A Meta-analysis.

Retinal vessel imaging is a noninvasive diagnostic tool used to evaluate cardiovascular risk. Childhood obesity and elevated blood pressure (BP) are associated with retinal microvascular alterations. To systematically review and meta-analyze associations between obesity, BP, and physical activity with retinal vessel diameters in children. We conducted a literature search through the databases of PubMed, Embase, Ovid, Web of Science, and the Cochrane Register of Controlled Trials. School- and population-based cross-sectional data. General information, study design, participants, exposure, and outcomes. A total of 1751 studies were found, and 30 full-text articles were analyzed for eligibility. Twenty-two articles (18 865 children and adolescents) were used for further assessment and reflection. Eleven articles were finally included in the meta-analysis. We found that a higher BMI is associated with narrower retinal arteriolar (pooled estimate effect size -0.37 [95% confidence interval (CI): -0.50 to -0.24]) and wider venular diameters (0.35 [95% CI: 0.07 to 0.63]). Systolic and diastolic BP are associated with retinal arteriolar narrowing (systolic BP: -0.63 [95% CI: -0.92 to -0.34]; diastolic BP: -0.60 [95% CI -0.95 to -0.25]). Increased physical activity and fitness are associated with favorable retinal vessel diameters. Long-term studies are needed to substantiate the prognostic relevance of retinal vessel diameters for cardiovascular risk in children. Our results indicate that childhood obesity, BP, and physical inactivity are associated with retinal microvascular abnormalities. Retinal vessel diameters seem to be sensitive microvascular biomarkers for cardiovascular risk stratification in children.

Risk Markers and Intermediate Outcomes in Research and Clinical Practice.

In adult cardiovascular disease, researchers have introduced a plethora of new imaging and biomarkers in hopes that these novel risk markers will either improve risk prediction for individuals, lend biological plausibility to modifying underlying behaviors or more aggressively treating traditional risk factors like blood pressure and lipids, or offer insights into pathophysiology that is amenable to drug therapy.1 One of these novel factors is retinal vessel diameters, which predict future cardiovascular outcomes, at least in women.2–4 In this issue of Pediatrics , Kochli et al5 examine retinal vessel diameters in children. They posit that physical activity, BMI, and blood pressure affect retinal vessel diameters, which reflect early signs of microvascular disease, which, in turn, leads to adult cardiovascular outcomes. With this article, we provide an opportunity to consider when novel risk factors are useful either in making clinical decisions or in research. Pediatric clinicians often use risk markers, by themselves or in combination with … Address correspondence to Alan E. Simon, MD, Environmental Influences on Child Health Outcomes Program, National Institutes of Health, 6011 Executive Blvd, Suite 325, Room 316, Rockville, MD 20852. E-mail: alan.simon{at}nih.gov

EFFECTS OF INTRAVITREAL RANIBIZUMAB AND BEVACIZUMAB ON THE RETINAL VESSEL SIZE IN DIABETIC MACULAR EDEMA.

The goal of this study was to assess the effects of a single injection of intravitreal ranibizumab (RAN) or bevacizumab (BEV) on the retinal vessel size in eyes with diabetic macular edema. In total, 32 patients were enrolled in the RAN group, and 30 patients were included in BEV group. Each of these groups was also subdivided into two others groups: a study group and a control group. The study groups were composed of the injected eyes, whereas the noninjected fellow eyes served as the control groups. The patients underwent complete ophthalmic examinations, including optical coherence tomography and fundus fluorescein angiography, and the primary outcome measures included the central retinal artery equivalent, central retinal vein equivalent, and artery-to-vein ratio. In the RAN study group (n = 32), the preinjection mean central retinal artery equivalent (175.42 μm) decreased to 169.01 μm after 1 week, and to 167.47 μm after 1 month (P < 0.001), whereas the baseline central retinal vein equivalent (235.29 μm) decreased initially to 219.90 μm after 1 week, and to 218.36 μm after 1 month (P < 0.001). In the BEV study group (n = 30), the preinjection central retinal artery equivalent (150.21 μm) decreased to 146.25 μm after 1 week, and to 145.89 μm after 1 month (P < 0.001); whereas the baseline central retinal vein equivalent (211.87 μm) decreased initially to 204.59 μm after 1 week and was 205.24 μm after 1 month (P < 0.001). The preinjection artery-to-vein ratio values changed significantly (P = 0.001) after 1 week and after 1 month in the RAN group, but no significant alteration in the artery-to-vein ratio was observed in the BEV group (P = 0.433). In both the RAN (n = 32) and BEV (n = 30) control groups, none of the 3 parameters changed throughout the study period, when compared with the baseline. The results of this study showed that both RAN and BEV injections significantly constricted the retinal blood vessel diameters.

The effect of autoimmune retinopathy on retinal vessel oxygen saturation.

To study the retinal vessel oxygen saturation alterations in patients with autoimmune retinopathy (AIR) and patients with autoimmune retinopathy associated with retinitis pigmentosa (AIR-RP) in comparison with healthy controls and patients with isolated retinitis pigmentosa (RP). Prospective, cross-sectional, and non-interventional study. Retinal vessel oximetry (RO) was performed on a total of 139 eyes: six eyes suffering from AIR and four eyes with AIR-RP were compared to 59 healthy control eyes and to 70 eyes with RP. A computer-based program of the retinal vessel analyser unit (IMEDOS Systems UG, Jena, Germany) was used to evaluate retinal vessel oxygen saturation. The mean oxygen saturation in the first and second branch retinal arterioles (A-SO2) and venules (V-SO2) were measured and their difference (A-V SO2) was calculated. In addition, we measured the diameter of the retinal arterioles (D-A) and venules (D-V). Oxygen metabolism is altered in patients with isolated AIR and AIR-RP. Both, AIR and AIR-RP groups, differed from healthy controls showing significantly higher V-SO2 values and significantly lower A-V SO2 values (p < 0.025). In addition, the AIR-RP group could be differentiated from eyes suffering from isolated RP by means of significantly higher V-SO2 values. Comparing retinal vessel diameters, both, the AIR and AIR-RP groups, presented with significant arterial (p = 0.05) and venular (p < 0.03) vessel attenuation than the healthy control group. Based on our results, in analogy to patients suffering from RP, oxygen metabolism seems to be altered in AIR patients.

The Relationship of Retinal Vessel Geometric Characteristics to the Incidence and Progression of Diabetic Retinopathy

To examine the relationships of retinal vessel geometric characteristics (RVGCs) to the incidence and progression of diabetic retinopathy (DR). Observational, prospective cohort study. Nine hundred ninety-six persons with type 1 diabetes mellitus (T1DM) and 1370 persons with type 2 diabetes mellitus (T2DM) seen at a baseline examination who were eligible for follow-up examinations at subsequent 5-year intervals. A total of 3846 person-interval data from these follow-up examinations are the basis for the analyses. Diabetic retinopathy and macular edema were assessed by grading of 30° stereoscopic color fundus photographs. Retinal vessel geometric characteristics were assessed using the Singapore I Vessel Assessment program from a digitized copy of 1 of the field 1 fundus photographs obtained at baseline and follow-up. The 5-year incidence of any DR, progression of DR, and incidence of proliferative diabetic retinopathy (PDR) and clinically significant macular edema (CSME) in right eyes. Incident DR occurred in 45%, progression in 32%, PDR in 10%, and CSME in 5%. While adjusting for glycated hemoglobin, duration of diabetes, and other factors, retinal arteriolar simple tortuosity was associated significantly with the incidence of any DR (odds ratio [OR], 1.17; 95% confidence interval [CI], 1.01-1.35). Retinal venular branching angle was associated significantly with progression of DR (OR, 1.18; 95% CI, 1.03-1.36), retinal venular curvature tortuosity was associated significantly with the incidence of PDR (OR, 1.15; 95% CI, 1.01-1.30), and retinal venular branching angle (OR, 1.41; 95% CI, 1.10-1.82) was associated significantly with the incidence of CSME. There were no significant associations of other RVGCs with any of the DR outcomes in the full multivariate model. Inclusion of all possible RVGCs did not improve the predictive value of the models that already included retinal vessel diameter and baseline DR severity level. Retinal vessel geometric characteristics of the retinal venules were associated with progression of DR; however, most of the RVGCs measured from digitized fundus photographs added little to the assessment of risk of incidence and progression of DR when other risk factors were considered in T1DM and T2DM.

Short-term effects of physical activity, air pollution and their interaction on the cardiovascular and respiratory system

Physical activity (PA) in urban environments may lead to increased inhalation of air pollutants. As PA and air pollution (AP) have respectively beneficial and detrimental effects on the cardiorespiratory system, the responses to these exposures can interact. Therefore, we assessed the short-term effects of PA, AP and their interaction on a set of subclinical cardiovascular and respiratory outcomes in a panel of healthy adults: heart rate variability (HRV), retinal vessel diameters, lung function and fractional exhaled nitric oxide (FeNO).One hundred twenty two participants measured their PA level and exposure to black carbon (BC), a marker of AP exposure, with wearable sensors during an unscripted week in three different seasons. The study was part of the PASTA project in three European cities (Antwerp: 41 participants, Barcelona: 41 participants, London: 40 participants). At the end of each measurement week, the health outcomes were evaluated. Responses to PA, BC and their interaction were assessed with mixed effect regression models. Separate models were used to account for a 2-h and 24-h time window.During the 2-h time window, HRV and lung function changed statistically significantly in response to PA (METhours) and logarithmic BC (%change). Changes in HRV marked an increased sympathetic tone with both PA (logarithmic LF/HF: +7%; p < 0.01) and BC (logarithmic HF: −19%; p < 0.05). In addition, PA provoked bronchodilation which was illustrated by a significant increase in lung function (FEV1: +15.63 mL; p < 0.05). While a BC %increase was associated with a significant lung function decrease (PEF: −0.10 mL; p < 0.05), the interaction indicated a potential protective effect of PA (p < 0.05). We did not observe a response of the retinal vessel diameters. Most subclinical outcomes did not change in the 24-h time window (except for a few minor changes in LF/HF, FeNO and PEF).Our results on the separate and combined effects of short-term PA and AP exposure on subclinical markers of the cardiorespiratory system are relevant for public health. We provide insights on the physiological responses of multiple, complementary markers. This may move further research towards elucidating potential pathways to disease and the long-term clinical impact of the observed physiological changes.