Proinflammatory and Hyperinsulinemic Dietary Patterns Are Associated With Specific Profiles of Biomarkers Predictive of Chronic Inflammation, Glucose-Insulin Dysregulation, and Dyslipidemia in Postmenopausal Women

Background: Dietary patterns promoting hyperinsulinemia and chronic inflammation, including the empirical dietary index for hyperinsulinemia (EDIH) and empirical dietary inflammatory pattern (EDIP), have been shown to strongly influence risk of weight gain, type 2 diabetes, cardiovascular disease, and cancer. EDIH was developed using plasma C-peptide, whereas EDIP was based on plasma C-reactive protein (CRP), interleukin-6, and tumor necrosis factor alpha receptor 2 (TNF-αR2). We investigated whether these dietary patterns were associated with a broader range of relevant biomarkers not previously tested.Methods: In this cross-sectional study, we included 35,360 women aged 50–79 years from the Women's Health Initiative with baseline (1993–1998) fasting blood samples. We calculated EDIH and EDIP scores from baseline food frequency questionnaire data and tested their associations with 40 circulating biomarkers of insulin response/insulin-like growth factor (IGF) system, chronic systemic inflammation, endothelial dysfunction, lipids, and lipid particle size. Multivariable-adjusted linear regression was used to estimate the percent difference in biomarker concentrations per 1 standard deviation increment in dietary index. FDR-adjusted p < 0.05 was considered statistically significant.Results: Empirical dietary index for hyperinsulinemia (EDIH) and empirical dietary inflammatory pattern (EDIP) were significantly associated with altered concentrations of 25 of the 40 biomarkers examined. For EDIH, the percent change in biomarker concentration in the insulin-related biomarkers ranged from +1.3% (glucose) to +8% (homeostatic model assessment for insulin resistance) and −9.7% for IGF-binding protein-1. EDIH impacted inflammation and endothelial dysfunction biomarkers from +1.1% (TNF-αR2) to +7.8% (CRP) and reduced adiponectin by 2.4%; and for lipid biomarkers: +0.3% (total cholesterol) to +3% (triglycerides/total cholesterol ratio) while reducing high-density lipoprotein cholesterol by 2.4%. EDIP showed a similar trend of associations with most biomarkers, although the magnitude of association was slightly weaker for the insulin-related biomarkers and stronger for lipids and lipid particle size.Conclusions: Dietary patterns with high potential to contribute to insulin hypersecretion and to chronic systemic inflammation, based on higher EDIH and EDIP scores, were associated with an unfavorable profile of circulating biomarkers of glucose-insulin dysregulation, chronic systemic inflammation, endothelial dysfunction and dyslipidemia. The broad range of biomarkers further validates EDIH and EDIP as mechanisms-based dietary patterns for use in clinical and population-based studies of metabolic and inflammatory diseases.

Effects of Mucoadhesive Polymers on Released Particles and Drug Release in Solid Lipid Particle-Based Buccal Tablets

Background: Mucoadhesive polymers play a critical role in controlled release tablets for buccal drug delivery. Objective: This research aimed to investigate the characterization and mechanisms of solid lipid particle-based tablets with different mucoadhesive polymers for buccal delivery. Methods: Prednisolone (PSL)-loaded solid lipid particles (SLPs) were conventionally prepared by ultrasonication. The freeze-drying method was used to convert the SLP suspension into a solid dosage form for buccal delivery by using mucoadhesive polymers. Results: All formulations showed over 80% drug release after 6 h, which followed immediate and sustained release patterns depending on the SLP type. However, the different polymers in the formulations resulted in different mucoadhesion times and drug release and drug permeability profiles. HPMC 4000 showed higher drug permeation (3327 μg vs. 2589 μg after 6 h) but a shorter mucoadhesion time than Carbopol (197 min vs. 361 min). In addition, surface morphology, swelling and erosion, particle size and zeta potential were also noted for the different mechanisms for buccal tablet design with different controlled release profiles. Conclusion: The results of this work indicate a good strategy for the selection of mucoadhesive polymers for SLP-based tablets in improving the bioavailability of poorly water-soluble drugs.

Functional solubilisation of the β2-adrenoceptor (β2AR) using Diisobutylene maleic acid (DIBMA)

The β2-adrenoceptor (β2AR) is a well-established target in asthma and a prototypical GPCR for biophysical studies. Solubilisation of membrane proteins has classically involved the use of detergents. However, the detergent environment differs from the native membrane environment and often destabilises membrane proteins. Use of amphiphilic copolymers is a promising strategy to solubilise membrane proteins within their native lipid environment in the complete absence of detergents. Here we show the isolation of the β2AR in the polymer Diisobutylene maleic acid (DIBMA). We demonstrate that β2AR remains functional in the DIBMA lipid particle (DIBMALP) and shows improved thermal stability compared to the n-Dodecyl-β-D-Maltopyranoside (DDM) detergent solubilised β2AR. This unique method of extracting β2AR offers significant advantages over previous methods routinely employed such as the introduction of thermostabilising mutations and the use of detergents, particularly for functional biophysical studies.

Diisobutylene Maleic Acid Copolymer (DIBMA) Lipid Particle: A “Stealth” Membrane Mimetic for Neutron Scattering

Diisobutylene maleic acid (DIBMA) has been shown to solubilize and purify membrane proteins from a native lipid bilayer into nanodiscs without the need for a detergent. To explore DIBMA lipid particles as a suitable membrane mimetic system for neutron scattering studies of membrane proteins, we measured and determined the contrast matching point of DIBMA to be ~12% (v/v) D2O—similar to that of most protiated lipid molecules, but distinct from that of regular protiated proteins, providing a natural contrast for separating neutron scattering signals. Using SANS contrast variation, we demonstrated that the scattering from the whole lipid particle can be annihilated. Further, the lipid part of the particle shows a well-defined discoidal shape with DIBMA contrast matched. These results demonstrate that the DIBMA lipid particle is an outstanding “stealth” membrane mimetic for membrane proteins.<br>

Diisobutylene Maleic Acid Copolymer (DIBMA) Lipid Particle: A “Stealth” Membrane Mimetic for Neutron Scattering

Diisobutylene maleic acid (DIBMA) has been shown to solubilize and purify membrane proteins from a native lipid bilayer into nanodiscs without the need for a detergent. To explore DIBMA lipid particles as a suitable membrane mimetic system for neutron scattering studies of membrane proteins, we measured and determined the contrast matching point of DIBMA to be ~12% (v/v) D2O—similar to that of most protiated lipid molecules, but distinct from that of regular protiated proteins, providing a natural contrast for separating neutron scattering signals. Using SANS contrast variation, we demonstrated that the scattering from the whole lipid particle can be annihilated. Further, the lipid part of the particle shows a well-defined discoidal shape with DIBMA contrast matched. These results demonstrate that the DIBMA lipid particle is an outstanding “stealth” membrane mimetic for membrane proteins.<br>

Delayed nucleation in lipid particles

Lipid particle crystallization shows non-classical nucleation and growth kinetics and demonstrates a tunable cooperative phase-transition with long characteristic timescales.

Nano-encapsulated Escherichia coli Divisome Anchor ZipA, and in Complex with FtsZ

The E. coli membrane protein ZipA, binds to the tubulin homologue FtsZ, in the early stage of cell division. We isolated ZipA in a Styrene Maleic Acid lipid particle (SMALP) preserving its position and integrity with native E. coli membrane lipids. Direct binding of ZipA to FtsZ is demonstrated, including FtsZ fibre bundles decorated with ZipA. Using Cryo-Electron Microscopy, small-angle X-ray and neutron scattering, we determine the encapsulated-ZipA structure in isolation, and in complex with FtsZ to a resolution of 1.6 nm. Three regions can be identified from the structure which correspond to, SMALP encapsulated membrane and ZipA transmembrane helix, a separate short compact tether, and ZipA globular head which binds FtsZ. The complex extends 12 nm from the membrane in a compact structure, supported by mesoscale modelling techniques, measuring the movement and stiffness of the regions within ZipA provides molecular scale analysis and visualisation of the early divisome.