Macular pigment optical density is related to blood glutathione levels in healthy individuals

Purpose. To assess the relationship between macular pigment optical density (MPOD) and blood markers for antioxidant defense in otherwise healthy volunteers. Methods. Forty-seven healthy volunteers were subjected to blood analysis to detect the level of circulating glutathione in its reduced (GSH) and oxidized (GSSG) forms. The level of MPOD was measured using heterochromatic flicker photometry. Systemic blood pressure (BP) parameters, heart rate (HR), body mass index (BMI), and plasma levels of total, HDL, and LDL cholesterol and triglycerides (TGs) were also determined. Results. A simple correlation model revealed that the level of MPOD correlated significantly and positively with both GSH (P < 0.001) and t-GSH (P < 0.001) levels but not with those of GSSG (P > 0.05). Age, sex, systemic BP parameters, HR, BMI, and plasma levels of cholesterol and TGs did not have any influence on either MPOD or glutathione levels (all P > 0.05). In addition, a forward stepwise multiple regression analysis showed MPOD to have a significantly and independent correlation with GSH levels (ß = 0.63; P < 0.001). Conclusions. In otherwise healthy older individuals, there is a positive correlation between local and systemic antioxidant defense mechanisms.

Reduction in blood glutathione levels occurs similarly in patients with primary-open angle or normal tension glaucoma

PURPOSE. To investigate in parallel the systemic glutathione levels of patients suffering from primary open angle glaucoma (POAG) or normal tension glaucoma (NTG) with comparable functional loss. METHODS. Thirty-four POAG patients, 30 NTG patients, and 53 controls were subjected to blood analysis to detect the level of circulating glutathione in its reduced (GSH) and oxidized (GSSG) forms. Systemic blood pressure (BP) and ocular perfusion pressure (OPP) parameters were also determined. RESULTS. Independent of age, POAG and NTG patients demonstrated significantly lower GSH and t-GSH levels than age-matched controls (P < 0.001). Additionally, a lower redox index was found, but in POAG patients only, in comparison to both NTG and control groups (P = 0.020). GSSG levels were, however, similar between all study groups (P > 0.05). CONCLUSIONS. This study demonstrates, for the first time, that both POAG and NTG patients exhibit lower GSH and t-GSH levels than age-matched controls, indicating a similar general compromise of the antioxidant defense systems may exist in both conditions. © 2013 The Association for Research in Vision and Ophthalmology, Inc.

Patients with early age-related macular degeneration exhibit signs of macro- and micro-vascular disease and abnormal blood glutathione levels

Background: This pilot study aimed to investigate systemic and retinal vascular function and their relationship to circulatory markers of cardiovascular risk in early age-related macular degeneration (AMD) patients without any already diagnosed systemic vascular pathologies. Methods: Fourteen patients diagnosed with early AMD and 14 age- and gender-matched healthy controls underwent blood pressure, carotid intima-media thickness (C-IMT) and peripheral arterial stiffness measurements. Retinal vascular reactivity was assessed by means of dynamic retinal vessel analysis (DVA) using a modified protocol. Blood analyses were conducted for glutathione levels and plasma levels of total cholesterol (CHOL), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and triglycerides (TG). Results: The AMD patients showed significantly greater C-IMT (p = 0.029) and augmentation index (AIx) (p = 0.042) than the age-matched controls. In addition, they demonstrated a shallower retinal arterial dilation slope (Slope AD) (p = 0.005) and a longer retinal venous reaction time (RT) to flickering light (p = 0.026). Blood analyses also revealed that AMD patients exhibited higher oxidized glutathione (GSSG) (p = 0.024), lower redox index (p = 0.043) and higher LDL-C (p = 0.033) levels than the controls. Venous RT parameter correlated positively with blood GSSG levels (r = 0.58, p = 0.038) in AMD subjects, but not in the controls (p > 0.05). Conclusions: Patients diagnosed with early AMD exhibit signs of systemic and retinal vascular alterations that correlated with known risk markers for future cardiovascular morbidity. © 2013 Springer-Verlag Berlin Heidelberg.

Effects of short-term detraining on postprandial metabolism, endothelial function, and inflammation in endurance-trained men:dissociation between changes in triglyceride metabolism and endothelial function

Endurance-trained athletes experience a low level of postprandial lipaemia, but this rapidly increases with detraining. We sought to determine whether detraining-induced changes to postprandial metabolism influenced endothelial function and inflammation. Eight endurance-trained men each undertook two oral fat tolerance tests [blood taken fasted and for 6 h following a high-fat test meal (80 g fat, 80 g carbohydrate)]: one during a period of their normal training (trained) and one after 1 wk of no exercise (detrained). Endothelial function in the cutaneous microcirculation was assessed using laser Doppler imaging with iontophoresis in the fasted state and 4 h postprandially during each test. Fasting plasma triglyceride (TG) concentrations increased by 35% with detraining (P = 0.002), as did postprandial plasma (by 53%, P = 0.002), chylomicron (by 68%, P = 0.02) and very low-density lipoprotein (by 51%, P = 0.005) TG concentrations. Endothelial function decreased postprandially in both the trained (by 17%, P = 0.03) and detrained (by 22%, P = 0.03) conditions but did not differ significantly between the trained and detrained conditions in either the fasted or the postprandial states. These results suggest that, although fat ingestion induces endothelial dysfunction, interventions that alter postprandial TG metabolism will not necessarily concomitantly influence endothelial function.

Individual variability analysis of fluorescence parameters measured in skin with different levels of nutritive blood flow

Fluorescence spectroscopy has recently become more common in clinical medicine. However, there are still many unresolved issues related to the methodology and implementation of instruments with this technology. In this study, we aimed to assess individual variability of fluorescence parameters of endogenous markers (NADH, FAD, etc.) measured by fluorescent spectroscopy (FS) in situ and to analyse the factors that lead to a significant scatter of results. Most studied fluorophores have an acceptable scatter of values (mostly up to 30%) for diagnostic purposes. Here we provide evidence that the level of blood volume in tissue impacts FS data with a significant inverse correlation. The distribution function of the fluorescence intensity and the fluorescent contrast coefficient values are a function of the normal distribution for most of the studied fluorophores and the redox ratio. The effects of various physiological (different content of skin melanin) and technical (characteristics of optical filters) factors on the measurement results were additionally studied.The data on the variability of the measurement results in FS should be considered when interpreting the diagnostic parameters, as well as when developing new algorithms for data processing and FS devices.

Oxidised LDL lipids, statins and a blood-brain barrier

Elevated cholesterol in mid-life has been associated with increased risk of dementia in later life. We have previously shown that low density lipoprotein (LDL) is more oxidised in the plasma of dementia patients although total cholesterol levels remained unchanged. Increased systemic oxidative modification (oxLDL) and nitration is also observed during hypercholesterolemia. We have investigated the hypothesis that disruption of blood brain barrier (BBB) function by oxLDL and their lipids may increase risk of neurodegeneration in later life and that statin intervention can mitigate the effects of hyperlipidaemia in mid-life. LDL isolated from statin-naïve hypercholesterolaemic subjects had higher mobility by agarose gel electrophoresis (Rf;0.53±0.06) and 8-isoprostane F2α concentration (43.5±8.42pg/ml) compared to control subjects (Rf; 0.46±0.05 and 24.2±5.37pg/ml respectively; p<0.05). Compared to HMVEC treatment with the LDL-lipids (5μM) from normolipidaemic subjects, LDL-lipids from hypercholesterolaemic subjects increased barrier permeability (103.4±12.5 Ωcm2 v 66.7±7.3 Ωcm2,P<0.01) and decreased cellular glutathione levels (18.5nmol/mg v 12.3nmol/mg) compared to untreated cells (26.2±3.6nmol/mg). LDL-lipids isolated from normolipidaemic subjects shows reduced risk to damage a BBB model compared with LDL-lipids from hypercholesterolaemic subjects. Moreover, a three month statin-intervention reduced the propensity for LDL-lipids from subjects with hyperlipidaemia to damage HMVEC. Post-statin treatment the cytotoxic and pro-inflammatory effects of LDL lipids disappeared. These data support the hypothesis that in vivo intervention with statins modifies LDL lipid oxidation, exerting a protective effect against in microvascular damage independent of cholesterol concentration.

Modified lipids from LDL in the blood during mid-life increase blood brain barrier permeability

Low density lipoprotein levels (LDL) are consistently elevated in cardiovascular disease. It has been suggested that those with high circulating LDL levels in mid-life may be susceptible to develop neurodegenerative diseases in later life. In the circulation, high levels of LDL are associated with increased oxidative modification (oxLDL) and nitration. We have investigated the hypothesis that disruption of blood brain barrier function by oxLDL and their lipids may increase risk of neurodegeneration in later life and that statin intervention in mid-life can mitigate the neurodegenerative effects of hyperlipidaemia. Blood from statin-naïve, normo- and hyperlipidaemic subjects (n=10/group) was collected at baseline. Hyperlipidaemic subjects received statin-intervention whereas normolipidaemic subjects did not prior to a second blood sampling, taken after 3 months. The intervention will be completed in June 2013. Plasma was separated by centrifugation (200g, 30min) and LDL was isolated by potassium bromide density gradient ultracentrifugation. Total homocysteine, LDL cholesterol, 8-isoprostane F2α levels were measured in plasma using commercial kits. LDL were analysed by agarose gel electrophoresis. LDL-lipids were extracted by partitioning in 1:1 chloroform:methanol (v/v) and conjugated to fatty acid free-BSA in serum-free EGM-2 medium (4hrs, 370C) for co-culture with human microvascular endothelial cells (HMVEC). HMVEC were maintained on polycarbonate inserts for two weeks to create a microvascular barrier. Change in barrier permeability was measured by trans-endothelial electrical resistance (TER), FITC-dextran permeability and immunohistochemistry. HMVEC glutathione (GSH) levels were measured after 2 hours by GSH-glo assay. LDL isolated from statin-naïve hyperlipidaemic subjects had higher mobility by agarose gel electrophoresis (Rf;0.53±0.06) and plasma 8-isoprostane F2α (43.5±8.42 pg/ml) compared to control subjects (0.46±0.05 and 24.2±5.37 pg/ml; p<0.05). Compared to HMVEC treatment with the LDL-lipids (5μM) from normolipidaemic subjects, LDL-lipids from hyperlipidaemic subjects increased barrier permeability (103.4±12.5 Ωcm2 v 66.7±7.3 Ωcm2,P<0.01) and decreased GSH (18.5 nmol/mg v 12.3 nmol/mg; untreated cells 26.2±3.6 nmol/mg).

AltitudeOmics: Red Blood Cell metabolic adaptation to high altitude hypoxia

Red blood cells (RBCs) are key players in systemic oxygen transport. RBCs respond to in vitro hypoxia  through  the so-called  oxygen-dependent  metabolic  regulation,  which  involves  the competitive  binding  of  deoxyhemoglobin  and  glycolytic  enzymes  to  the  N-terminal  cytosolic domain  of  band  3.  This  mechanism  promotes  the  accumulation  of  2,3-DPG,  stabilizing  the deoxygenated state of hemoglobin, and cytosol acidification, triggering oxygen off-loading through the  Bohr  effect.  Despite  in  vitro  studies,  in  vivo adaptations  to  hypoxia  have  not  yet  been completely elucidated. Within  the  framework  of  the AltitudeOmics  study,  erythrocytes  were  collected  from  21 healthy volunteers at sea level, after exposure to high altitude (5260m) for 1, 7 and 16days, and following  reascent  after  7days  at 1525m.  UHPLC-MS  metabolomics  results  were  correlated  to physiological and athletic performance parameters. Immediate  metabolic  adaptations  were  noted as early as a few hours from ascending  to >5000m, and maintained for 16 days at high altitude.  Consistent with the mechanisms elucidated in vitro, hypoxia promoted glycolysis and deregulated the pentose phosphate pathway, as well purine catabolism, glutathione homeostasis, arginine/nitric oxide and sulphur/H2S metabolism. Metabolic adaptations were preserved one week after descent, consistently with improved physical performances in comparison to the first ascendance, suggesting a mechanism of metabolic memory.

Balance ability in 7- and 10-year-old children:associations with prenatal lead and cadmium exposure and with blood lead levels in childhood in a prospective birth cohort study

OBJECTIVES: Most studies reporting evidence of adverse effects of lead and cadmium on the ability to balance have been conducted in high-exposure groups or have included adults. The effects of prenatal exposure have not been well studied, nor have the effects in children been directly studied. The aim of the study was to identify the associations of lead (in utero and in childhood) and cadmium (in utero) exposure with the ability to balance in children aged 7 and 10 years. DESIGN: Prospective birth cohort study. PARTICIPANTS: Maternal blood lead (n=4285) and cadmium (n=4286) levels were measured by inductively coupled plasma mass spectrometry in women enrolled in the Avon Longitudinal Study of Parents and Children (ALSPAC) during pregnancy. Child lead levels were measured in a subsample of 582 of ALSPAC children at age 30 months. MAIN OUTCOME MEASURES: Children completed a heel-to-toe walking test at 7 years. At 10 years, the children underwent clinical tests of static and dynamic balance. Statistical analysis using SPSS V.19 included logistic regression modelling, comparing categories of ≥ 5 vs <5 µg/dL for lead, and ≥ 1 vs <1 µg/L for cadmium. RESULTS: Balance at age 7 years was not associated with elevated in utero lead or cadmium exposure (adjusted OR for balance dysfunction: Pb 1.01 (95% CI 0.95 to 1.01), n=1732; Cd 0.95 (0.77 to 1.20), n=1734), or with elevated child blood lead level at age 30 months (adjusted OR 0.98 (0.92 to 1.05), n=354). Similarly, neither measures of static nor dynamic balance at age 10 years were associated with in utero lead or cadmium exposure, or child lead level. CONCLUSIONS: These findings do not provide any evidence of an association of prenatal exposure to lead or cadmium, or lead levels in childhood, on balance ability in children. Confirmation in other cohorts is needed.