Nanoparticle Wettability Influences Nanoparticle-Phospholipid Interactions.

We explored the influence of nanoparticle (NP) surface charge and hydrophobicity on NP-biomolecule interactions by measuring the composition of adsorbed phospholipids on four NPs, namely, positively charged CeO2 and ZnO and negatively charged BaSO4 and silica-coated CeO2, after exposure to bronchoalveolar lavage fluid (BALf) obtained from rats, and to a mixture of neutral dipalmitoyl phosphatidylcholine (DPPC) and negatively charged dipalmitoyl phosphatidic acid (DPPA). The resulting NP-lipid interactions were examined by cryogenic transmission electron microscopy (cryo-TEM) and atomic force microscopy (AFM). Our data show that the amount of adsorbed lipids on NPs after incubation in BALf and the DPPC/DPPA mixture was higher in CeO2 than in the other NPs, qualitatively consistent with their relative hydrophobicity. The relative concentrations of specific adsorbed phospholipids on NP surfaces were different from their relative concentrations in the BALf. Sphingomyelin was not detected in the extracted lipids from the NPs despite its >20% concentration in the BALf. AFM showed that the more hydrophobic CeO2 NPs tended to be located inside lipid vesicles, whereas less hydrophobic BaSO4 NPs appeared to be outside. In addition, cryo-TEM analysis showed that CeO2 NPs were associated with the formation of multilamellar lipid bilayers, whereas BaSO4 NPs with unilamellar lipid bilayers. These data suggest that the NP surface hydrophobicity predominantly controls the amounts and types of lipids adsorbed, as well as the nature of their interaction with phospholipids.

Protein corona: implications for nanoparticle interactions with pulmonary cells.

BACKGROUND: We previously showed that cerium oxide (CeO2), barium sulfate (BaSO4) and zinc oxide (ZnO) nanoparticles (NPs) exhibited different lung toxicity and pulmonary clearance in rats. We hypothesize that these NPs acquire coronas with different protein compositions that may influence their clearance from the lungs. METHODS: CeO2, silica-coated CeO2, BaSO4, and ZnO NPs were incubated in rat lung lining fluid in vitro. Then, gel electrophoresis followed by quantitative mass spectrometry was used to characterize the adsorbed proteins stripped from these NPs. We also measured uptake of instilled NPs by alveolar macrophages (AMs) in rat lungs using electron microscopy. Finally, we tested whether coating of gold NPs with albumin would alter their lung clearance in rats. RESULTS: We found that the amounts of nine proteins in the coronas formed on the four NPs varied significantly. The amounts of albumin, transferrin and α-1 antitrypsin were greater in the coronas of BaSO4 and ZnO than that of the two CeO2 NPs. The uptake of BaSO4 in AMs was less than CeO2 and silica-coated CeO2 NPs. No identifiable ZnO NPs were observed in AMs. Gold NPs coated with albumin or citrate instilled into the lungs of rats acquired the similar protein coronas and were cleared from the lungs to the same extent. CONCLUSIONS: We show that different NPs variably adsorb proteins from the lung lining fluid. The amount of albumin in the NP corona varies as does NP uptake by AMs. However, albumin coating does not affect the translocation of gold NPs across the air-blood barrier. A more extensive database of corona composition of a diverse NP library will develop a platform to help predict the effects and biokinetics of inhaled NPs.

Screening for Chemical Toxicity Using Cryopreserved Precision Cut Lung Slices.

To assess chemical toxicity, current high throughput screening (HTS) assays rely primarily on in vitro measurements using cultured cells. Responses frequently differ from in vivo results due to the lack of physical and humoral interactions provided by the extracellular matrix, cell-cell interactions, and other molecular components of the native organ. To more accurately reproduce organ complexity in HTS, we developed an organotypic assay using the cryopreserved precision cut lung slice (PCLS) from rats and mice. Compared to the never-frozen PCLS, their frozen-thawed counterpart slices showed viability or metabolic activity that is decreased to an extent comparable to that observed in other cryopreserved cells and tissues, but shows no differences in further changes in cell viability, mitochondrial integrity, and glutathione activity in response to the model toxin zinc chloride (ZnCl2). Notably, these measurements were successfully miniaturized so as to establish HTS capacity in a 96-well plate format. Finally, PCLS responses correlated with common markers of lung injury measured in lavage fluid from rats intratracheally instilled with ZnCl2. In summary, we establish that the cryopreserved PCLS is a feasible approach for HTS investigations in predictive toxicology.

Impact of vitamin A megadose supplementation on the anthropometry of children and adolescents with non-hormonal statural deficit: a double-blind and randomized clinical study.

OBJECTIVE: To evaluate the intake of retinol and carotenoids, and their serum levels, as well as the impact of vitamin A supplementation on the anthropometry and body composition of children and adolescents with non-hormonal-related statural deficit. METHOD: Double-blind, randomized trial of 46 pre-pubertal patients, between 4 and 14 years of age, with normal growth rates. The subjects were divided into two groups, each with 23 individuals (Group I: Placebo; Group II: Vitamin A in a single megadose), and were evaluated at moments A and B with a six month interval. RESULTS: There were no statistically significant differences in serum retinol levels, anthropometry, growth velocity, or body composition, between moments A and B, in Group II. Carotenoids were significantly lower in Group I at moment B. The semi-quantitative food intake questionnaire showed that approximately 60.9% of the children and adolescents ingested less than half of the amounts of retinol and carotenoids recommended by the Food Guide Pyramid. Inadequate intake was more prevalent regarding vegetable and fruit carotenoid sources, with 75 and 70% of inadequacy, respectively. CONCLUSION: If one considers the inadequate food intake observed in the dietary evaluation in this study, it is possible that multiple micronutrient deficiencies could be involved in statural deficits. This could explain why vitamin A supplementation does not seem to influence growth in children and adolescents with statural deficit, as indicated by the present study. Thus in populations such as the one studied here, the supplementation with vitamin A should be integrated into comprehensive nutritional interventions, so as to possibly promote greater positive impact on linear growth.

[Vitamin A: blood level and dietetics intake in stunted children and adolescents without hormonal disease]. / Vitamina A: nível sérico e ingestão dietética em crianças e adolescentes com déficit estatural de causa não hormonal.

OBJECTIVES: To determine the vitamin A intake and the blood levels of carotenoids and retinol in stunted children and adolescents without hormonal disease, assisted in the Clinic of Pediatric Endocrinology of the Center for Nutrition and Child Development--Department of Health, State of São Paulo, Brazil. METHODS: We evaluated, in a prospective and randomized trial, 47 prepubertal patients between 4 and 14 years old. All patients were submitted to anthropometric evaluation, bone age, bioelectric impedance and serum retional and carotenoid levels. RESULTS: The average of the stature z score was -2.4; 20% of the patients were undernourished, 25.5% they had inadequacy of the fat mass as well as larger delay of the bone age. The more stunted the patients the lower were the carotenoid levels. There was no relationship between the levels of retinol and carotenoids and the growth velocity. In 82.9% of the recall record of food intake, the vitamin A intake was lower than 50% of the established one in the Food Guide Pyramid. CONCLUSION: There is a high prevalence of malnutrition, bone age delay and inadequacy of the levels of carotenoids and vitamin A intake in stunted children and adolescents.

Vitamina A: nível sérico e ingestäo dietética em crianças e adolecentes com déficit estatural de causa näo hormonal / Vitamin A: blood level and dietetics intake in stunted children and adolescents without hormonal disease

OBJETIVOS: Determinar a ingestäo dietética de vitamina A e os níveis séricos de carotenóides e retinol em crianças e adolescentes com déficit estatural sem causa hormonal, atendidos no Ambulatório de Endocrinopediatria do Núcleo de Nutriçäo (NUNADI) da Secretaria de Estado da Saúde de Säo Paulo. MÉTODOS: Foram avaliados de maneira prospectiva 47 pacientes pré-púberes, entre 4 e 14 anos, com relaçäo a: antropometria, idade óssea, inquérito alimentar, bioimpedanciometria e nível sérico de retinol e carotenóides. RESULTADOS: A média do escore Z da estatura foi de -2,4; 20 por cento dos pacientes eram desnutridos, 25,5 por cento tinham inadequaçäo da massa gorda e maior atraso da idade óssea. Os níveis séricos de retinol e carotenóides foram inadequados em 21 por cento dos pacientes, sendo que foi maior o percentual de inadequaçäo dos carotenóides nos pacientes que apresentavam déficit estatural mais acentuado. Näo houve relaçäo dos níveis séricos de retinol e carotenóides com a velocidade de crescimento. Em 82,9 por cento dos inquéritos alimentares realizados, houve ingestäo de vitamina A inferior a 50 por cento do estabelecido na Pirâmide de Alimentos. CONCLUSÄO: Baseados nestes resultados, concluímos que há uma elevada prevalência de desnutriçäo, comprometimento da idade óssea, inadequaçäo no nível sérico de carotenóides e ingestäo de vitamina A em crianças com comprometimento estatural