Développement d’une méthode analytique pour la spéciation du sélénium dans le plasma des Inuits du Nunavik

Le sélénium (Se) est très abondant dans l’alimentation marine traditionnelle des Inuits et par conséquent leur apport en Se est parmi les plus élevés au monde. Cette alimentation marine est une source importante de méthylmercure (MeHg) et un apport élevé en Se pourrait contrer certains de ses effets néfastes. Dans cette étude, une méthode de spéciation et de quantification du Se plasmatique et des fractions du Hg associées a été développée puis appliquée à des échantillons de plasma d’adultes inuits ayant participé à l’enquête de santé Qanuippitaa-2004. La glutathion peroxydase 3 (GPx3), la sélénoprotéine P (SelP) et la sélénoalbumine (SeAlb) représentaient en moyenne 25%, 52% et 23% du Se plasmatique total respectivement. En outre, l’Hg coéluait avec chacune de ces protéines dont 50% était associé à la SelP. La relation non linéaire observée entre les concentrations plasmatiques et sanguines de Se suggère qu’un sélénocomposé, possiblement la sélénonéine, s’accumule dans les cellules sanguines.Selenium (Se) is highly abundant in traditional marine foods consumed by Inuit and accordingly their Se intake is one of the highest in the world. These marine foods are also a replete of methylmercury (MeHg) and an elevated Se intake may offset some of its deleterious effects. In this study, a method for the speciation and quantification of Se and associated Hg fractions in human plasma was developed and then applied to plasma samples of Inuit adults who participated to the 2004 Qanuippitaa health survey. Glutathione peroxidase 3 (GPx3), selenoprotein P (SelP) and selenoalbumin (SeAlb) represented on average 25%, 52% and 23% of the total plasma Se concentration, respectively. In addition, Hg co-eluted with each Se-containing protein and 50% of plasma Hg was associated with SelP. A non-linear relationship was observed between plasma and blood Se, suggesting that a selenocompound, possibly selenoneine, accumulates in blood cells of our participants

Selenoneine is a major selenium species in beluga skin and red blood cells of Inuit from Nunavik

Nunavimmiut (Inuit of Nunavik, Northern Quebec, Canada) exhibit a high selenium (Se) status because oftheir frequent consumption of marine mammal foods. Indirect evidence from our previous studies hadsuggested that selenoneineea novel selenocompoundemay be accumulating in the blood of Nuna-vimmiut. We used a liquid-chromatography/inductively coupled tandem mass spectrometry (LC-ICP-MS/MS) method to measure concentrations of selenoneine and its methylated metabolite Se-methylselenoneine in archived red blood cells (RBC) obtained from 210 Nunavimmiut living in com-munities along the Hudson Strait, where marine mammal hunting and consumption are most frequent inNunavik. This method was adapted to quantify selenoneine and its methylated metabolite in belugamattaaq, an Inuit delicacy consisting of the skin with the underlying layer of fat and the major dietarysource of Se for Nunavimmiut. Total selenium concentration was also measured in RBC and belugamattaaq samples by isotope dilution ICP-MS/MS. The median selenoneine concentration in RBC was413mg Se/L (range¼3.20e3230mg Se/L), representing 54% (median) of total Se content (range¼1.6e91%). Quantification of selenoneine infive beluga mattaaq samples (skin layer) from Nunavik revealed amedian concentration of 1.8mg Se/g wet wt (range¼1.2e7.4mg Se/g), constituting 54% (median) of thetotal Se content (range¼44e74%). Se-methylselenoneine was also detected in Inuit RBC but not inbeluga mattaaq, suggesting that selenoneine undergoes methylation in humans. Selenoneine may protect Nunavimmiut from methylmecury toxicity by increasing its demethylation in RBC and in turndecreasing its distribution to target organs

Determinants of selenoneine concentration in red blood cells of Inuit from Nunavik (Northern Québec, Canada)

Selenium (Se) is a trace mineral essential to human health, and is especially abundant in marine foods consumed by Inuit populations in Nunavik (northern Quebec, Canada), leading to exceptionally high whole blood Se levels. While most epidemiological studies to date examine plasma or whole blood Se, little is known about the health implications of specific Se biomarkers (e.g. selenoproteins and small Se compounds). Selenoneine, a novel Se compound, is found in high concentrations in marine foods (and particularly beluga mattaaq) and the red blood cells (RBCs) of populations that consume them. We report here RBC selenoneine concentrations in a population of Inuit adults (n = 885) who participated in the Qanuippitaa? 2004 survey. Simple associations between RBC selenoneine and other Se and mercury (Hg) biomarkers were assessed using Spearman correlations and linear regressions. Wilcoxon ranksum tests were used to examine differences in biomarkers and characteristics between tertiles of RBC selenoneine concentration. A multiple linear regression analysis was used to determine factors (sociodemographic, lifestyle, and dietary) associated with RBC selenoneine concentrations. Selenoneine comprised a large proportion of whole blood Se and RBC Se in this population. Age and sex-adjusted geometric mean RBC selenoneine concentration was 118 μg/L (range: 1-3226 μg/L) and was much higher (p = 0.001) among women (150.3 μg/L) than men (87.6 μg/L) across all regions of Nunavik after controlling for age, region, and diet. RBC selenoneine was highly correlated with RBC Se (rs = 0.96, p < 0.001) and whole blood Se (rs = 0.89, p < 0.001), but only weakly correlated with plasma Se (rs = 0.13, p < 0.001). Overall, increasing age (standardized β = 0.24), higher body-mass index (BMI; β = 0.08), female sex (β = 0.10), living in a Hudson Strait community (compared to Hudson Bay and Ungava Bay; β = 0.38), and consuming beluga mattaaq (g/day; β = 0.19) were positively associated with RBC selenoneine. Meanwhile, consumption of market meats (g/day; β = -0.07) was negatively associated with RBC selenoneine. RBC selenoneine is an important biomarker of Se dietary intake from local marine foods in Inuit populations. Further studies are needed to examine the health effects of selenoneine intake and the underlying mechanisms for sex differences among Inuit populations

HIV-malaria interactions in North-East India: A prospective cohort study

Background & objectives: The interactions between HIV and malaria co-infection have been shown to influence each other in their clinical outcomes in Sub-Saharan Africa. This study was carried out in the two States of north east India endemic for both HIV and malaria infections, to study the interactions between the two diseases in the HIV-infected population. Methods: In this prospective study, a total of 333 HIV-infected individuals were followed up for a period of 6-18 months in Mizoram and Manipur during 2010-2011. The study assessed the changes in viral load and also the therapeutic efficacy of artesunate plus sulphadoxine-pyrimethamine (AS+SP) combination therapy in HIV-infected and HIV-uninfected individuals with Plasmodium falciparum malaria. Results: Viral load in HIV-infected malaria patients on day zero (D0) ranged from 1110 to 147,000 copies/ml. The log transformation of the geometric means of HIV viral loads revealed no significant difference on different days of follow up. There was 100 per cent adequate clinical and parasitological response (ACPR) after treating with artemisinin based combination therapy (ACT) both in HIV-infected and HIV-uninfected P. falciparum-positive individuals. Similarly, chloroquine showed 100 per cent ACPR in P. vivax HIV-infected individuals. Interpretation & conclusion: The study showed no significant increase in HIV viral load in malaria cases. All HIV-infected and HIV-uninfected P. falciparum malaria-positive cases responded to the treatment with 100 per cent ACPR

Gender-related differences in the management of hypertension by cardiologists: The PARITE study

SummaryBackgroundSeveral studies have shown gender differences in the management of cardiovascular risk factors and diseases. Whether the management of hypertension by cardiologists in France differs according to patient gender has not been fully investigated.AimsThe main objective of this cross-sectional, multicentre study was to examine the management according to gender of hypertensive patients by office-based cardiologists in France.MethodsCardiologists were asked to include consecutively two men and two women attending a routine consultation for essential hypertension. Therapeutic management was evaluated by comparing cardiovascular investigations in the preceding 6 months and hypertension control according to gender and the patients’ global cardiovascular risk.ResultsOverall, data from 3440 adult patients (53% men) referred to 654 cardiologists were analysed. Hypertension was uncontrolled in 76% of both men and women and 69% were at high global cardiovascular risk (75% of men, 62% of women; P<0.001). Significantly fewer cardiovascular investigations had been performed in the preceding 6 months in women (22.6% vs 44.2% in men; P<0.001). The treatment regimen was changed by the cardiologist in approximately 50% of patients regardless of gender or global cardiovascular risk.ConclusionsThe PARITE study shows that in French office-based cardiology practice, the antihypertensive regimen is adjusted as often in female as in male patients. However, the results suggest that there is room for improvement in the investigation of cardiovascular disease in women. Healthcare providers could be encouraged to implement established guidelines on the prevention of cardiovascular disease in women