A Healthy Diet is Associated with a Lower Risk of Hepatic Fibrosis.

BACKGROUND: Higher diet quality is associated with a lower risk of NAFLD. OBJECTIVES: We examined the relationship between diet quality and hepatic fibrosis. METHODS: We analyzed cross-sectional associations between 3 a priori diet quality scores-the Dietary Approaches to Stop Hypertension (DASH) score, the Alternative Healthy Eating Index (AHEI), and a modified Mediterranean-style Diet Score (MDS)-and hepatic fat [controlled attenuation parameter (CAP)] and fibrosis [liver stiffness measurement (LSM)] measured by vibration-controlled transient elastography (VCTE) in 2532 Framingham Heart Study (FHS) participants and 3295 participants of the National Health and Nutrition Examination Survey (NHANES). RESULTS: Higher diet quality scores were associated with lower LSM in both FHS and NHANES after adjustment for demographic and lifestyle factors. Additional adjustment for CAP or BMI attenuated the observed associations. Association strength was similar across all 3 diet quality scores. Fixed-effect meta-analysis demonstrated that, under CAP-adjusted models, the LSM decreases associated with 1-SD increase of the DASH, AHEI, and MDS scores were 2% (95% CI: 0.7%, 3.3%; P = 0.002), 2% (95% CI: 0.7%, 3.3%; P = 0.003), and 1.7% (95% CI: 0.7%, 2.6%; P = 0.001), respectively, whereas in the meta-analysis of BMI-adjusted models, LSM reductions associated with 1-SD increase of the DASH, AHEI, and MDS scores were 2.2% (95% CI: -0.1%, 2.2%; P = 0.07), 1.5% (95% CI: 0.3%, 2.7%; P = 0.02), and 0.9 (95% CI: -0.1%, 1.9%; P = 0.07), respectively. CONCLUSIONS: We demonstrated associations of higher diet quality with favorable hepatic fat and fibrosis measures. Our data suggest that a healthy diet may reduce the likelihood of obesity and hepatic steatosis as well as the progression of steatosis to fibrosis.

Branched-Tail Lipid Nanoparticles Potently Deliver mRNA In Vivo due to Enhanced Ionization at Endosomal pH.

The potential of mRNA therapeutics will be realized only once safe and effective delivery systems are established. Unfortunately, delivery vehicle development is stymied by an inadequate understanding of how the molecular properties of a vehicle confer efficacy. Here, a small library of lipidoid materials is used to elucidate structure-function relationships and identify a previously unappreciated parameter-lipid nanoparticle surface ionization-that correlates with mRNA delivery efficacy. The two most potent materials of the library, 306O10 and 306Oi10 , induce substantial luciferase expression in mice following a single 0.75 mg kg-1 mRNA dose. These lipidoids, which have ten-carbon tails and identical molecular weights, vary only in that the 306O10 tail is straight and the 306Oi10 tail has a one-carbon branch. Remarkably, this small difference in structure conferred a tenfold improvement in 306Oi10 efficacy. The enhanced potency of this branched-tail lipidoid is attributed to its strong surface ionization at the late endosomal pH of 5.0. A secondary lipidoid library confirms that Oi10 materials ionize more strongly and deliver mRNA more potently than lipidoids containing linear tails. Together, these data highlight the exquisite control that lipid chemistry exerts on the mRNA delivery process and show that branched-tail lipids facilitate protein expression in animals.

Temporal dynamics of the neural representation of hue and luminance polarity.

Hue and luminance contrast are basic visual features. Here we use multivariate analyses of magnetoencephalography data to investigate the timing of the neural computations that extract them, and whether they depend on common neural circuits. We show that hue and luminance-contrast polarity can be decoded from MEG data and, with lower accuracy, both features can be decoded across changes in the other feature. These results are consistent with the existence of both common and separable neural mechanisms. The decoding time course is earlier and more temporally precise for luminance polarity than hue, a result that does not depend on task, suggesting that luminance contrast is an updating signal that separates visual events. Meanwhile, cross-temporal generalization is slightly greater for representations of hue compared to luminance polarity, providing a neural correlate of the preeminence of hue in perceptual grouping and memory. Finally, decoding of luminance polarity varies depending on the hues used to obtain training and testing data. The pattern of results is consistent with observations that luminance contrast is mediated by both L-M and S cone sub-cortical mechanisms.

Color Space Geometry Uncovered with Magnetoencephalography.

The geometry that describes the relationship among colors, and the neural mechanisms that support color vision, are unsettled. Here, we use multivariate analyses of measurements of brain activity obtained with magnetoencephalography to reverse-engineer a geometry of the neural representation of color space. The analyses depend upon determining similarity relationships among the spatial patterns of neural responses to different colors and assessing how these relationships change in time. We evaluate the approach by relating the results to universal patterns in color naming. Two prominent patterns of color naming could be accounted for by the decoding results: the greater precision in naming warm colors compared to cool colors evident by an interaction of hue and lightness, and the preeminence among colors of reddish hues. Additional experiments showed that classifiers trained on responses to color words could decode color from data obtained using colored stimuli, but only at relatively long delays after stimulus onset. These results provide evidence that perceptual representations can give rise to semantic representations, but not the reverse. Taken together, the results uncover a dynamic geometry that provides neural correlates for color appearance and generates new hypotheses about the structure of color space.