Inaccurately Reported Statin Use Affects the Assessing of Lipid Profile Measures and Their Association with Coronary Artery Disease Risk.

Background: Lipid profiling is central for coronary artery disease (CAD) risk assessment. Nonadherence or unreported use of lipid-lowering drugs, particularly statins, can significantly complicate the association between lipid profile measures and CAD clinical outcomes. By combining medication history evaluation with statin analysis in plasma, we determined the effects of inaccurately reported statin use on lipid profile measures and their association with CAD risk.

Integrated Quantitative Targeted Lipidomics and Proteomics Reveal Unique Fingerprints of Multiple Metabolic Conditions.

Aberrations in lipid and lipoprotein metabolic pathways can lead to numerous diseases, including cardiovascular disease, diabetes, neurological disorders, and cancer. The integration of quantitative lipid and lipoprotein profiling of human plasma may provide a powerful approach to inform early disease diagnosis and prevention. In this study, we leveraged data-driven quantitative targeted lipidomics and proteomics to identify specific molecular changes associated with different metabolic risk categories, including hyperlipidemic, hypercholesterolemic, hypertriglyceridemic, hyperglycemic, and normolipidemic conditions.

Effect of the ABCA1 agonist CS-6253 on amyloid-β and lipoprotein metabolism in cynomolgus monkeys.

Background: Inducing brain ATP-binding cassette 1 (ABCA1) activity in Alzheimer's disease (AD) mouse models is associated with improvement in AD pathology. The purpose of this study was to investigate the effects of the ABCA1 agonist peptide CS-6253 on amyloid-β peptides (Aβ) and lipoproteins in plasma and cerebrospinal fluid (CSF) of cynomolgus monkeys, a species with amyloid and lipoprotein metabolism similar to humans.

Methods: CS-6253 peptide was injected intravenously into cynomolgus monkeys at various doses in three different studies.

The small HDL particle hypothesis of Alzheimer's disease.

We propose the hypothesis that small high-density lipoprotein (HDL) particles reduce the risk of Alzheimer's disease (AD) by virtue of their capacity to exchange lipids, affecting neuronal membrane composition and vascular and synaptic functions. Concentrations of small HDLs in cerebrospinal fluid (CSF) and plasma were measured in 180 individuals ≥60 years of age using ion mobility methodology. Small HDL concentrations in CSF were positively associated with performance in three domains of cognitive function independent of apolipoprotein E (APOE) ε4 status, age, sex, and years of education.

CETP Inhibition Improves HDL Function but Leads to Fatty Liver and Insulin Resistance in CETP-Expressing Transgenic Mice on a High-Fat Diet.

In clinical trials, inhibition of cholesteryl ester transfer protein (CETP) raises HDL cholesterol levels but does not robustly improve cardiovascular outcomes. Approximately two-thirds of trial participants are obese. Lower plasma CETP activity is associated with increased cardiovascular risk in human studies, and protective aspects of CETP have been observed in mice fed a high-fat diet (HFD) with regard to metabolic outcomes.

Core lipid, surface lipid and apolipoprotein composition analysis of lipoprotein particles as a function of particle size in one workflow integrating asymmetric flow field-flow fractionation and liquid chromatography-tandem mass spectrometry.

Lipoproteins are complex molecular assemblies that are key participants in the intricate cascade of extracellular lipid metabolism with important consequences in the formation of atherosclerotic lesions and the development of cardiovascular disease. Multiplexed mass spectrometry (MS) techniques have substantially improved the ability to characterize the composition of lipoproteins. However, these advanced MS techniques are limited by traditional pre-analytical fractionation techniques that compromise the structural integrity of lipoprotein particles during separation from serum or plasma.

High throughput quantification of apolipoproteins A-I and B-100 by isotope dilution MS targeting fast trypsin releasable peptides without reduction and alkylation.

Purpose: Apolipoprotein A-I (ApoA-I) and apolipoprotein B-100 (ApoB-100) are amphipathic proteins that are strong predictors of cardiovascular disease risk. The traceable calibration of apolipoprotein assays is a persistent challenge, especially for ApoB-100, which cannot be solubilized in purified form.

Experimental Design: A simultaneous quantitation method for ApoA-I and ApoB-100 was developed using tryptic digestion without predigestion reduction and alkylation, followed by LC separation coupled with isotope dilution MS analysis.

On-column trypsin digestion coupled with LC-MS/MS for quantification of apolipoproteins.

Unlabelled: Apolipoproteins measured in plasma or serum are potential biomarkers for assessing metabolic irregularities that are associated with the development of cardiovascular disease (CVD). LC-MS/MS allows quantitative measurement of multiple apolipoproteins in the same sample run. However, the accuracy and precision of the LC-MS/MS measurement depends on the reproducibility of the enzymatic protein digestion step.

Ultrafiltration improves ELISA and Endopep MS analysis of botulinum neurotoxin type A in drinking water.

The objective of this study was to adapt and evaluate two in vitro botulinum neurotoxin (BoNT) detection methods, including the Botulinum Toxin ELISA and the Endopep MS (a mass spectrometric-based endopeptidase method), for use with drinking water samples. The method detection limits (MDL) of the ELISA and Endopep MS were 260 pg/mL and 21 pg/mL of BoNT/A complex toxin, respectively. Since toxin could be present in water samples at highly dilute concentrations, large volume (100-L) samples of municipal tap water from five US municipalities having distinct water compositions were dechlorinated, spiked with 5 μg BoNT/A, and subjected to tangential-flow ultrafiltration (UF) using hollow fiber dialyzers.

Subtyping botulinum neurotoxins by sequential multiple endoproteases in-gel digestion coupled with mass spectrometry.

Botulinum neurotoxin (BoNT) is one of the most toxic substances known. BoNT is classified into seven distinct serotypes labeled A-G. Among individual serotypes, researchers have identified subtypes based on amino acid variability within a serotype and toxin variants with minor amino acid sequence differences within a subtype.

Quantification of botulinum neurotoxin serotypes A and B from serum using mass spectrometry.

Botulinum neurotoxins (BoNT) are the deadliest agents known. Previously, we reported an endopeptidase activity based method (Endopep-MS) that detects and differentiates BoNT serotypes A-G. This method uses serotype specific monoclonal antibodies and the specific enzymatic activity of BoNT against peptide substrates which mimic the toxin's natural target.

"Proteotyping": population proteomics of human leukocytes using top down mass spectrometry.

Characterizing combinations of coding polymorphisms (cSNPs), alternative splicing and post-translational modifications (PTMs) on a single protein by standard peptide-based proteomics is challenging owing to <100% sequence coverage and the uncoupling effect of proteolysis on such variations >10-20 residues apart. Because top down MS measures the whole protein, combinations of all the variations affecting primary sequence can be detected as they occur in combination. The protein form generated by all types of variation is here termed the "proteotype", akin to a haplotype at the DNA level.

Characterization of proteomic and metabolomic responses to dietary factors and supplements.

Over the past decade there has been a renewed interest in research and development of both dietary and nutritional supplements. Significant advancements have been made in the scientific assessment of the quality, safety, and efficacy of these products because of the strong interest in and financial support of these projects. As research in both fields continues to advance, opportunities to use new and innovative research technologies and methodologies, such as proteomics and metabolomics, are critical for the future progress of the science.

Top-down proteomics on a chromatographic time scale using linear ion trap fourier transform hybrid mass spectrometers.

Proteomics has grown significantly with the aid of new technologies that consistently are becoming more streamlined. While processing of proteins from a whole cell lysate is typically done in a bottom-up fashion utilizing MS/MS of peptides from enzymatically digested proteins, top-down proteomics is becoming a viable alternative that until recently has been limited largely to offline analysis by tandem mass spectrometry. Here we describe a method for high-resolution tandem mass spectrometery of intact proteins on a chromatographic time scale.

Top-down approaches for measuring expression ratios of intact yeast proteins using Fourier transform mass spectrometry.

The extension of quantitation methods for small peptides to ions above 5 kDa, and eventually to global quantitative proteomics of intact proteins, will require extensive refinement of current analytical approaches. Here we evaluate postgrowth Cys-labeling and 14N/15N metabolic labeling strategies for determination of relative protein expression levels and their posttranslational modifications using top-down mass spectrometry (MS). We show that intact proteins that are differentially alkylated with acrylamide (+71 Da) versus iodoacetamide (+57 Da) have substantial chromatographic shifts during reversed-phase liquid chromatography separation (particularly in peak tails), indicating a requirement for stable isotopes in alkylation tags for top-down MS.