Protein interaction, monocyte toxicity and immunogenic properties of cerium oxide crystals with 5% or 14% gadolinium, cobalt oxide and iron oxide nanoparticles - an interdisciplinary approach

Metal oxide nanoparticles are widely used in both consumer products and medical applications, but the knowledge regarding exposure-related health effects is limited. However, it is challenging to investigate nanoparticle interaction processes with biological systems. The overall aim of this project was to improve the possibility to predict exposure-related health effects of metal oxide nanoparticles through interdisciplinary collaboration by combining workflows from the pharmaceutical industry, nanomaterial sciences, and occupational medicine. Specific aims were to investigate nanoparticle-protein interactions and possible adverse immune reactions. Four different metal oxide nanoparticles; CeOx nanocrystals with 5% or 14% Gd, Co3O4, and Fe2O3, were characterized by dynamic light scattering and high-resolution transmission electron microscopy. Nanoparticle-binding proteins were identified and screened for HLA-binding peptides in silico. Monocyte interaction with nanoparticle-protein complexes was assessed in vitro. Herein, for the first time, immunogenic properties of nanoparticle-binding proteins have been characterized. The present study indicates that especially Co3O4-protein complexes can induce both danger signals, verified by the production of inflammatory cytokines and simultaneously bind autologous proteins, which can be presented as immunogenic epitopes by MHC class II. The clinical relevance of these findings should be further evaluated to investigate the role of metal oxide nanoparticles in the development of autoimmune disease. The general workflow identified experimental difficulties, such as nanoparticle aggregate formation and a lack of protein-free buffers suitable for particle characterization, protein analyses, as well as for cell studies. This confirms the importance of future interdisciplinary collaborations.Funding Agencies|Region Ostergotland ALF [LIO-606891]; AFA insurances [150246]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]; Knut and Alice Wallenberg FoundationKnut &amp; Alice Wallenberg Foundation [2012.0083 CTS, 18:399]; Center in Nano Science and Nano technology at LiTH (CeNano) at Linkoping University</p

Bariatric surgery improves lipoprotein profile in morbidly obese patients by reducing LDL cholesterol, apoB, and SAA/PON1 ratio, increasing HDL cholesterol, but has no effect on cholesterol efflux capacity

BACKGROUND: Bariatric surgery has been shown to reduce cardiovascular events and cause specific mortality for coronary artery disease in obese patients. Lipoprotein biomarkers relating to low-density lipoprotein (LDL), high-density lipoprotein (HDL), their subfractions, and macrophage cholesterol efflux have all been hypothesized to be of value in cardiovascular risk assessment. OBJECTIVES: The objective of this study was to examine the effect of a lifestyle intervention followed by bariatric surgery on the lipid profile of morbidly obese patients. METHODS: Thirty-four morbidly obese patients were evaluated before and after lifestyle changes and then 1 year after bariatric surgery. They were compared with 17 lean subjects. Several lipoprotein metrics, serum amyloid A (SAA), serum paraoxonase-1 (PON1), and macrophage cholesterol efflux capacity (CEC) were assessed. RESULTS: Average weight loss after the lifestyle intervention was 10.5% and 1 year after bariatric surgery was 33.9%. The lifestyle intervention significantly decreased triglycerides (TGs; 28.7 mg/dL, P amp;lt; .05), LDL cholesterol (LDL-C; 32.3 mg/dL, P amp;lt; .0001), and apolipoprotein B (apoB; 62.9 mu g/mL, P amp;lt; .001). Bariatric surgery further reduced TGs (-36.7 mg/dL, P amp;lt; .05), increased HDL cholesterol (+12 mg/dL, P amp;lt; .0001), and reductions in LDL-C and apoB were sustained. Bariatric surgery reduced large, buoyant LDL (P amp;lt; .0001), but had no effect on the small, dense LDL.The large HDL subfractions increased (P amp;lt; .0001), but there was no effect on the smaller HDL sub fractions. The ratio for SAA/PON1 was reduced after the lifestyle intervention (P amp;lt; .01) and further reduced after bariatric surgery (P amp;lt; .0001). Neither the lifestyle intervention nor bariatric surgery had any effect on CEC. CONCLUSIONS: Lifestyle intervention followed by bariatric surgery in 34 morbidly obese patients showed favorable effects on TGs, LDL-C, and apoB. HDL cholesterol and apoA1 was increased, apoB/apoA1 ratio as well as SAA/PON1 ratio reduced, but bariatric surgery did not influence CEC. (C) 2017 National Lipid Association. All rights reserved