Passage of uranium through human cerebral microvascular endothelial cells: influence of time exposure in mono- and co-culture in vitro models.

PURPOSE: Depleted uranium (DU) has several civilian and military applications. The effects of this emerging environmental pollutant on human health raise some concerns. Previous experimental studies have shown that uranium (U) exposure can disturb the central nervous system. A small quantity of U reaches the brain via the blood, but the effects on the blood-brain barrier (BBB) remain unclear. MATERIALS AND METHODS: In the present work, two cell culture models were exposed to DU for different times to study its cytotoxicity, paracellular permeability and extracellular concentration of U. The well-known immortalized human cerebral microvascular endothelial cells, hCMEC/D3, were cultured on the filter in the first model. In the second model, human primary cells of pericytes were cultured under the filter to understand the influence of cell environment after U exposure. RESULTS: The results show that U is not cytotoxic to hCMEC/D3 cells or pericytes until 500 µM (1.6 Bq.L-1). In addition, acute or chronic low-dose exposure of U did not disturb permeability and was conserved in both cell culture models. However, U is able to reach the brain compartment. During the first hours of exposure, the passage of U to the abluminal compartment was significantly reduced in the presence of pericytes. Electronic microscopy studies evidenced the formation of needlelike structures, like urchin-shaped precipitates, from 1 h of exposure. Analytical microscopy confirmed the U composition of these precipitates. Interestingly, precipitated U was detected only in endothelial cells and not in pericytes. U was localized in multilamellar or multivesicular bodies along the endo-lysosomal pathway, suggesting the involvement of these traffic vesicles in U sequestration and/or elimination. CONCLUSIONS: We show for the first time the in vitro passage of U across a human cerebral microvascular endothelial cells, and the intracellular localization of U precipitates without any cytotoxicity or modification of paracellular permeability. The difference between the results obtained with monolayers and co-culture models with pericytes illustrates the need to use complex in vitro models in order to mimic the neurovascular unit. Further in vivo studies should be performed to better understand the passage of U across the blood-brain barrier potentially involved in behavioral consequences.

Impact of pH on Urine Chemistry Assayed on Roche Analyzers.

BACKGROUND: The pH may impact the concentration of certain urinary parameters, making urine pre-treatment questionable. METHODS: 1) Determining the impact of pH in vitro on the urinary concentration of chemistry parameters assayed on Roche Modular analyzers. 2) Evaluating whether concentrations depended on pH in non-pretreated urines from patients. RESULTS: 1) The optimal urinary pH values for each measurement were: 6.3 ± 0.8 (amylase), < 5.5 (calcium and magnesium), < 6.5 (phosphorus), > 6.5 (uric acid). Urinary creatinine, sodium and urea concentrations were not pH-dependent. 2) In urines from patients, the pH was negatively associated with the concentration of some urinary parameters. However, concentrations of all the parameters were strongly and positively correlated with urinary creatinine, and relationships with pH were no longer evidenced after creatinine-normalization. CONCLUSIONS: The need for urine pH adjustment does not seem necessary when considering renal function. However, from an analytical and accreditation standpoint, the relationship between urine pH and several parameters justifies its measurement.

Glucose tolerance and cardiovascular risk biomarkers in non-diabetic non-obese obstructive sleep apnea patients: Effects of long-term continuous positive airway pressure.

BACKGROUND: Insulin resistance, glucose dyshomeostasis and oxidative stress are associated to the cardiovascular consequences of obstructive sleep apnea (OSA). The effects of a long-term continuous positive airway pressure (LT-CPAP) treatment on such mechanisms still remain conflicting. OBJECTIVE: To investigate the effect of LT-CPAP on glucose tolerance, insulin sensitivity, oxidative stress and cardiovascular biomarkers in non-obese non-diabetic OSA patients. PATIENTS & METHODS: Twenty-eight apneic, otherwise healthy, men suffering from OSA (mean age = 48.9 ± 9.4 years; apnea-hypopnea index = 41.1 ± 16.1 events/h; BMI = 26.6 ± 2.8 kg/m(2); fasting glucose = 4.98 ± 0.37 mmol/L) were evaluated before and after LT-CPAP by an oral glucose tolerance test (OGTT), measuring plasma glucose, insulin and proinsulin. Glycated hemoglobin, homeostasis model assessment resistance insulin, blood lipids, oxidative stress, homocysteine and NT-pro-brain natriuretic peptide (NT-proBNP) were also measured. RESULTS: LT-CPAP treatment lasted 13.9 ± 6.5 months. At baseline, the time spent at SaO2<90%, minimal and mean SaO2 were associated with insulin area under the curve during OGTT (r = 0.448, P = 0.011; r = -0.382; P = 0.047 and r = -0.424; P = 0.028, respectively) and most other glucose/insulin homeostasis biomarkers, as well as with homocysteine (r = 0.531, P = 0.006; r = -0.487; P = 0.011 and r = -0.409; P = 0.034, respectively). LT-CPAP had no effect on all the OGTT-related measurements, but increased plasma total antioxidant status (+7.74%; P = 0.035) in a duration-dependent manner (r = 0.607; P < 0.001), and decreased both homocysteine (-15.2%; P = 0.002) and NT-proBNP levels (-39.3%; P = 0.002). CONCLUSIONS: In non-obese non-diabetic OSA patients, nocturnal oxygen desaturation is strongly associated to insulin resistance. LT-CPAP does not improve glucose homeostasis nor insulin sensitivity but has a favorable effect on antioxidant capacity and cardiovascular risk biomarkers.

Sleep quality, sleep duration and physical activity in obese adolescents: effects of exercise training.

BACKGROUND: Decreased sleep duration and altered sleep quality are risk factors for obesity in youth. Structured exercise training has been shown to increase sleep duration and improve sleep quality. OBJECTIVES: This study aimed at evaluating the impact of exercise training for improving sleep duration, sleep quality and physical activity in obese adolescents (OB). METHODS: Twenty OB (age: 14.5 ± 1.5 years; body mass index: 34.0 ± 4.7 kg m(-2) ) and 20 healthy-weight adolescents (HW) completed an overnight polysomnography and wore an accelerometer (SenseWear Bodymedia) for 7 days. OB participated in a 12-week supervised exercise-training programme consisting of 180 min of exercise weekly. Exercise training was a combination of aerobic exercise and resistance training. RESULTS: Sleep duration was greater in HW compared with OB (P < 0.05). OB presented higher apnoea-hypopnoea index than HW (P < 0.05). Physical activity (average daily metabolic equivalent of tasks [METs]) by accelerometer was lower in OB (P < 0.05). After exercise training, obese adolescents increased their sleep duration (+64.4 min; effect size: 0.88; P = 0.025) and sleep efficiency (+7.6%; effect size: 0.76; P = 0.028). Physical activity levels were increased in OB as evidenced by increased steps per day and average daily METs (P < 0.05). Improved sleep duration was associated with improved average daily METs (r = 0.48, P = 0.04). CONCLUSION: The present study confirms altered sleep duration and quality in OB. Exercise training improves sleep duration, sleep quality and physical activity.

Impact of exercise training without caloric restriction on inflammation, insulin resistance and visceral fat mass in obese adolescents.

BACKGROUND: Exercise training has been shown to improve cardiometabolic health in obese adolescents. OBJECTIVES: Evaluate the impact of a 12-week exercise-training programme (without caloric restriction) on obese adolescents' cardiometabolic and vascular risk profiles. METHODS: We measured systemic markers of oxidation, inflammation, metabolic variables and endothelial function in 20 obese adolescents (OB) (age: 14.5 ± 1.5 years; body mass index: 34.0 ± 4.7 kg m(-2) ) and 20 age- and gender-matched normal-weight adolescents (NW). Body composition was assessed by magnetic resonance imagery. Peak aerobic capacity and maximal fat oxidation were evaluated during specific incremental exercise tests. OB participated in a 12-week exercise-training programme. RESULTS: OB presented lower peak aerobic capacity (24.2 ± 5.9 vs. 39.8 ± 8.3 mL kg(-1) min(-1) , P < 0.05) and maximal fat oxidation compared with NW (P < 0.05). OB displayed greater F2t-Isoprostanes (20.5 ± 6.7 vs. 13.4 ± 4.2 ng mmol(-1) creatinine), Interleukin-1 receptor antagonist (IL-1Ra) (1794.8 ± 532.2 vs. 835.1 ± 1027.4 pg mL(-1) ), Tumor Necrosis Factor-α (TNF-α) (2.1 ± 1.2 vs. 1.5 ± 1.0 pg mL(-1) ), Soluble Tumor Necrosis Factor-α Type II Receptor (sTNFαRII), leptin, insulin, homeostasis model assessment of insulin resistance, version 2 (HOMA2-IR), high-sensitive C-reactive protein, triglycerides and lower adiponectin and high-density lipoprotein cholesterol (all P < 0.05). After exercise training, despite lack of weight loss, VO2peak (mL.kg(-1) .min(-1) ) and maximal fat oxidation increased (P < 0.05). IL-1Ra and IFN-gamma-inducible protein 10 (IP-10) decreased (P < 0.05). Insulin and HOMA2-IR decreased (14.8 ± 1.5 vs. 10.2 ± 4.2 µUI mL(-1) and 1.9 ± 0.8 vs. 1.3 ± 0.6, respectively, P < 0.05). Change in visceral fat mass was inversely associated with change in maximal fat oxidation (r = -0.54; P = 0.024). The subgroup of participants that lost visceral fat mass showed greater improvements in triglycerides, insulin resistance and maximal fat oxidation. CONCLUSION: Our data confirms the role of exercise training on improving the inflammatory profile and insulin resistance of OB in the absence of weight loss. However, those who lost a greater amount of visceral fat mass showed greater benefits in terms of insulin profile, triglycerides and maximal fat oxidation.

Prognostic value of liver fibrosis and steatosis biomarkers in type-2 diabetes and dyslipidaemia.

BACKGROUND: In cardiometabolic disorders, non-alcoholic fatty liver disease is frequent and presumably associated with increased mortality and cardiovascular risk. AIM: To evaluate the prognostic value of non-invasive biomarkers of liver fibrosis (FibroTest) and steatosis (SteatoTest) in patients with type-2 diabetes and/or dyslipidaemia. METHODS: A total of 2312 patients with type-2 diabetes and/or dyslipidaemia were included and prospectively followed up for 5-15 years. The cardiovascular Framingham-risk score was calculated; advanced fibrosis and severe steatosis, were defined by FibroTest >0.48 and SteatoTest >0.69, respectively, as previously established. RESULTS: During a median follow-up of 12 years, 172 patients (7.4%) died. The leading causes of mortality were cancer (31%) and cardiovascular-related death (20%). The presence of advanced fibrosis [HR (95% CI)] [2.98 (95% CI 1.78-4.99); P < 0.0001] or severe steatosis [1.86 (1.34-2.58); P = 0.0002] was associated with an increased risk of mortality. In a multivariate Cox model adjusted for confounders: the presence of advanced fibrosis was associated with overall mortality [1.95 (1.12-3.41); P = 0.02]; advanced fibrosis at baseline [n = 50/677; 1.92 (1.04-3.55); P = 0.04] and progression to advanced fibrosis during follow-up [n = 16/127; 4.8 (1.5-14.9); P = 0.007] were predictors of cardiovascular events in patients with type-2 diabetes. In patients with a Framingham-risk score ≥20%, the presence of advanced fibrosis was predictive of cardiovascular events [2.24 (1.16-4.33); P < 0.05]. CONCLUSIONS: Liver biomarkers, such as FibroTest and SteatoTest, have prognostic values in patients with metabolic disorders. FibroTest has prognostic value for predicting overall survival in patients with type-2 diabetes and/or dyslipidaemia. In type-2 diabetes, FibroTest predicted cardiovascular events and improved the Framingham-risk score.

Evaluation of LOCI technology-based thyroid blood tests on the Dimension Vista analyzer.

OBJECTIVES: To assess the performance of thyroid-stimulating hormone (TSH), free thyroxine (FT4) and free triiodothyronine (FT3) determinations by luminescent oxygen channeling immunoassay (LOCI) technology on the Dimension Vista analyzer (Siemens Healthcare Diagnostics). DESIGN & METHODS: We assessed 1) functional sensitivity for TSH (FSe-TSH), and intra- and inter-assay variations for TSH, FT4 and FT3 on Vista; 2) comparisons of serum and heparin-treated plasma on Vista; 3) comparisons of a) plasma TSH by Vista versus electrochemiluminescence (ECLIA) on Roche Modular analyzer, and b) plasma FT4 and FT3 by Vista versus Immunotech-Beckman radioimmunoassay (RIA); and 4) association of albumin and prealbumin levels with free thyroid hormone concentrations on Vista. RESULTS: 1) FSe-TSH concentration was below 0.005 mIU/L. Maximum intra-assay CVs (2.1%, 1.4%, 5.2%) and inter-assay CVs (16.5%, 5.1%, 5.8%) were good for TSH, FT4 and FT3 respectively. 2) Heparin-treated plasma samples consistently gave slightly higher values than serum for TSH, FT4 and FT3. 3) Passing-Bablok regression gave: TSH: [LOCI]=0.91[ECLIA]-0.08 (concordance correlation coefficient ρ(c)=0.95); FT4: [LOCI]=1.05[RIA]-1.55 (ρ(c)=0.80); and FT3: [LOCI]=1.05[RIA]-0.06 (ρ(c)=0.81). 4) Both serum albumin and prealbumin concentrations were positively associated with FT3 levels and negatively associated with FT4 levels in patients. CONCLUSION: LOCI is accurate for TSH, FT4 and FT3 analysis. Despite a slight significant bias compared to ECLIA, LOCI is precise for TSH and fulfills the third-generation criteria. However, the poor concordance between LOCI and RIA for FT4 and FT3, and the dependence of these hormones on binding proteins require further investigation.

The impact of obstructive sleep apnea on homocysteine and carotid remodeling in metabolic syndrome.

Obstructive sleep apnea (OSA) and metabolic syndrome (MetS) are associated with increased cardiovascular morbidity and mortality. Increased homocysteine is suggested as an independent risk factor for atherosclerosis and cardiovascular disease but remains disputed in OSA. We assessed polysomnography, carotid intima-media thickness (CIMT) and biology in 35 MetS patients, according to the presence (OSA+MetS; n=26) or the absence of OSA (MetS; n=9). In OSA+MetS patients, homocysteine levels were increased compared to MetS subjects (12.8 ± 3.8 vs. 9.5 ± 2.5 µmol/L; P=0.026). In the whole population, homocysteine correlated with apnea-hypopnea index (AHI) (r=0.522; P=0.001) and CIMT (r=0.376; P=0.026). Homocysteine was negatively correlated with plasma thiols (r=-0.406; P=0.017) and positively with urinary 15-F2t-isoprostanes (r=0.347; P=0.044). Multivariate regression analysis revealed that AHI (ß=0.559; P<0.001) and urinary 15-F2t-isoprostane (ß=0.310; P=0.018) were independently associated with homocysteine level. We conclude that homocysteine level was higher in MetS when associated with OSA and proportional to OSA severity. In this context, vascular remodeling appeared more severe and mediated by oxidative stress.

Plasma 15-F2t isoprostane concentrations are increased during acute fructose loading in type 2 diabetes.

OBJECTIVE: Fructose consumption is increasing worldwide and is likely to play a role in metabolic disorders. Dietary fructose is often recommended for diabetic patients, as this form of carbohydrate leads to a lower postprandial rise in plasma glucose and insulin. However, fructose contributes to the generation of free radicals. The aim of this work was to investigate the acute effects of a fructose load in patients with type 2 diabetes mellitus (T2DM), compared with healthy controls, on several metabolic oxidative biomarkers, particularly plasma 15-F2t isoprostanes (15-F2t isoPs). RESEARCH DESIGN AND METHODS: Six T2DM patients and six healthy subjects were recruited. All patients underwent a single fructose tolerance test (75 g of anhydrous fructose). Plasma 15-F2t isoPs concentrations, plasma total antioxidant capacity (TAS) and thiobarbituric acid reactive substances (TBARS) were measured at baseline, and at 60, 120, 180 and 240 min after fructose absorption. RESULTS: Baseline plasma 15-F2t isoPs concentrations were significantly increased in T2DM patients compared with controls (310+/-47 versus 237+/-20 pg/mL, respectively; P<0.01) and rose significantly (P<0.01) to 414+/-45 pg/mL in diabetic patients. No change in TAS or TBARS was observed in either group. CONCLUSION: Plasma 15-F2t isoPs are increased during acute fructose loading in T2DM. Knowing the potentially deleterious effect of plasma 15-F2t isoPs-in particular, vascular lesions-and in light of our results, it is necessary to reconsider fructose consumption in T2DM patients, as we can now show, for the first time, a possible association between acute fructose loading and deleterious effects in such patients.