Quantitative detection of amyloid-β peptides by mass spectrometry: state of the art and clinical applications

2015 ◽  
Vol 53 (10) ◽  
Author(s):  
Pauline Bros ◽  
Vincent Delatour ◽  
Jérôme Vialaret ◽  
Béatrice Lalere ◽  
Nicolas Barthelemy ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Amyloid Β ◽  
Clinical Applications ◽  
Health Concern ◽  
Quantitative Detection ◽  
Csf Biomarkers ◽  
Aβ Peptides ◽  
The Past ◽  
Analytical Phase ◽  
Interesting Alternative

AbstractAlzheimer’s disease (AD) is the most common form of dementia in humans, and a major public health concern with 35 million of patients worldwide. Cerebrospinal fluid (CSF) biomarkers being early diagnostic indicators of AD, it is essential to use the most efficient analytical methods to detect and quantify them accurately. These biomarkers, and more specifically amyloid-β (Aβ) peptides, are measured in routine clinical practice using immunoassays. However, there are several limits to this immunodetection in terms of specificity and multiplexing of the multiple isoforms of the Aβ peptides. To overcome these issues, the quantification of these analytes by mass spectrometry (MS) represents an interesting alternative, and several assays have been described over the past years. This article reviews the different Aβ peptides quantitative MS-based approaches published so far, compares their pre-analytical phase, and the different quantitative strategies implemented that might be suitable for clinical applications.

Cerebrospinal fluid biomarkers of β-amyloid metabolism in multiple sclerosis

2012 ◽  
Vol 19 (5) ◽  
pp. 543-552 ◽  
Author(s):  
Kristin Augutis ◽  
Markus Axelsson ◽  
Erik Portelius ◽  
Gunnar Brinkmalm ◽  
Ulf Andreasson ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Cerebrospinal Fluid ◽  
Inflammatory Diseases ◽  
Amyloid Β ◽  
Csf Biomarkers ◽  
Aβ Peptide ◽  
Aβ Peptides ◽  
App Metabolism ◽  
Disease Modifying

Background: Amyloid precursor protein (APP) and amyloid β (Aβ) peptides are intensely studied in neuroscience and their cerebrospinal fluid (CSF) measurements may be used to track the metabolic pathways of APP in vivo. Reduced CSF levels of Aβ and soluble APP (sAPP) fragments are reported in inflammatory diseases, including multiple sclerosis (MS); but in MS, the precise pathway of APP metabolism and whether it can be affected by disease-modifying treatments remains unclear. Objective: To characterize the CSF biomarkers of APP degradation in MS, including the effects of disease-modifying therapy. Methods: CSF samples from 87 MS patients (54 relapsing–remitting (RR) MS; 33 secondary progressive (SP) MS and 28 controls were analyzed for sAPP and Aβ peptides by immunoassays, plus a subset of samples was analyzed by immunoprecipitation and mass spectrometry (IP-MS). Patients treated with natalizumab or mitoxantrone were examined at baseline, and after 1–2 years of treatment. Results: CSF sAPP and Aβ peptide levels were reduced in MS patients; but they increased again towards normal, after natalizumab treatment. A multivariate model of IP-MS-measured Aβ species separated the SPMS patients from controls, with RRMS patients having intermediate levels. Conclusions: We confirmed and extended our previous observations of altered CSF sAPP and Aβ peptide levels in MS patients. We found that natalizumab therapy may be able to counteract the altered APP metabolism in MS. The CSF Aβ isoform distribution was found to be distinct in SPMS patients, as compared to the controls.

scholarly journals Quantitative Measurement of Cerebrospinal Fluid Amyloid-β Species by Mass Spectrometry

2020 ◽  
pp. 1-12
Author(s):  
Yusuke Seino ◽  
Takumi Nakamura ◽  
Tomoo Harada ◽  
Naoko Nakahata ◽  
Takeshi Kawarabayashi ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cerebrospinal Fluid ◽  
Quantitative Measurement ◽  
Amyloid Β ◽  
High Sensitivity ◽  
Csf Biomarkers ◽  
Strongly Correlated ◽  
Csf Levels

Background: High sensitivity liquid chromatography mass spectrometry (LC-MS/MS) was recently introduced to measure amyloid-β (Aβ) species, allowing for a simultaneous assay that is superior to ELISA, which requires more assay steps with multiple antibodies. Objective: We validated the Aβ1-38, Aβ1-40, Aβ1-42, and Aβ1-43 assay by LC-MS/MS and compared it with ELISA using cerebrospinal fluid (CSF) samples to investigate its feasibility for clinical application. Methods: CSF samples from 120 subjects [8 Alzheimer’s disease (AD) with dementia (ADD), 2 mild cognitive dementia due to Alzheimer’s disease (ADMCI), 14 cognitively unimpaired (CU), and 96 neurological disease subjects] were analyzed. Aβ species were separated using the Shimadzu Nexera X2 system and quantitated using a Qtrap 5500 LC-MS/MS system. Aβ1-40 and Aβ1-42 levels were validated using ELISA. Results: CSF levels in CU were 666±249 pmol/L in Aβ1-38, 2199±725 pmol/L in Aβ1-40, 153.7±79.7 pmol/L in Aβ1-42, and 9.78±4.58 pmol/L in Aβ1-43. The ratio of the amounts of Aβ1-38, Aβ1-40, Aβ1-42, and Aβ1-43 was approximately 68:225:16:1. Linear regression analyses showed correlations among the respective Aβ species. Both Aβ1-40 and Aβ1-42 values were strongly correlated with ELISA measurements. No significant differences were observed in Aβ1-38 or Aβ1-40 levels between AD and CU. Aβ1-42 and Aβ1-43 levels were significantly lower, whereas the Aβ1-38/1-42, Aβ1-38/1-43, and Aβ1-40/Aβ1-43 ratios were significantly higher in AD than in CU. The basic assay profiles of the respective Aβ species were adequate for clinical usage. Conclusion: A quantitative LC-MS/MS assay of CSF Aβ species is as reliable as specific ELISA for clinical evaluation of CSF biomarkers for AD.

scholarly journals Establishing pre-analytical requirements and maximizing peptide recovery in the analytical phase for mass spectrometric quantification of amyloid-β peptides 1–42 and 1–40 in CSF

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Lauren M. Forgrave ◽  
J. Grace van der Gugten ◽  
Quyen Nguyen ◽  
Mari L. DeMarco
Keyword(s):  
Mass Spectrometry ◽  
Clinical Laboratory ◽  
Comprehensive Evaluation ◽  
Solid Phase ◽  
Amyloid Β ◽  
Careful Consideration ◽  
Mass Spectrometric ◽  
Analytical Sensitivity ◽  
Surrogate Matrix ◽  
Analytical Phase

Abstract Objectives Amyloid-β (Aβ) peptides in cerebrospinal fluid (CSF), including Aβ42 (residues 1–42) and Aβ40 (residues 1–40), are utilized as biomarkers in the diagnostic workup of Alzheimer’s disease. Careful consideration has been given to the pre-analytical and analytical factors associated with measurement of these peptides via immunoassays; however, far less information is available for mass spectrometric methods. As such, we performed a comprehensive evaluation of pre-analytical and analytical factors specific to Aβ quantification using mass spectrometry. Methods Using our quantitative mass spectrometry assay for Aβ42 and Aβ40 in CSF, we investigated the potential for interference from hemolysate, bilirubin, lipids, and anti-Aβ-antibodies. We also optimized the composition of the calibrator surrogate matrix and Aβ recovery during and after solid phase extraction (SPE). Results There was no interreference observed with total protein up to 12 g/L, hemolysate up to 10% (v/v), bilirubin up to 0.5% (v/v), intralipid up to 1% (v/v), or anti-Aβ-antibodies at expected therapeutic concentrations. For hemolysate, bilirubin and lipids, visual CSF contamination thresholds were established. In the analytical phase, Aβ recovery was increased by ∼50% via SPE solvent modifications and by over 150% via modification of the SPE collection plate, which also extended analyte stability in the autosampler. Conclusions Attention to mass spectrometric-specific pre-analytical and analytical considerations improved analytical sensitivity and reproducibility, as well as, established CSF specimen acceptance and rejection criteria for use by the clinical laboratory.

scholarly journals Mutations in the juxtamembrane segment of the cholesterol-binding site of APP alter its processing and promotes production of shorter, less toxic Aβ peptides

2020 ◽  
Author(s):  
Linda Hanbouch ◽  
Béatrice Schaack ◽  
Amal Kasri ◽  
Gaëlle Fontaine ◽  
Eleni Gkanatsiou ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Binding Site ◽  
Amyloid Β ◽  
Neuronal Cultures ◽  
Membrane Cholesterol ◽  
Aβ Peptides ◽  
App Processing ◽  
Juxtamembrane Region ◽  
Early Endosomes ◽  
Cholesterol Binding

AbstractBackgroundThe brains of patients with Alzheimer’s disease (AD) reveal increased cellular membrane levels of cholesterol. Correspondingly, we previously showed that elevating levels of membrane cholesterol in neuronal cultures recapitulates early AD phenotypes including excessive cleavage of amyloid β (Aβ) peptides from the amyloid precursor protein (APP). Here we aimed to evaluate how the presence of a cholesterol-binding site (CBS) in the transmembrane and juxtamembrane regions of APP regulates its processing.MethodsWe generated seven single and two double APP mutants at amino acid positions 22, 26, 28, 29, 33, 39 of the Aβ sequence changing the charge and/or hydrophobicity of the targeted amino acids. HEK293T cells were transfected with APP constructs and secreted Aβ peptides were measured using ELISA and mass spectrometry (MS). APP processing in normal and high cholesterol condition, and endocytosis were assessed in stably expressing APPwt and APPK28A HEK293T clones. Finally, we measured the binding of synthetic peptides derived from the Aβ sequence to cholesterol-rich exosomes purified from control HEK293T cells.ResultsMost mutations triggered a reduction in the production of Aβ40 and Aβ42 peptides, whereas only juxtamembrane mutants resulted in the generation of shorter Aβ peptides. We confirmed by mass spectrometry this specific change in the profile of secreted Aβ peptides for the most characteristic APPK28A mutant. A transient increase of plasma membrane cholesterol enhanced the production of Aβ40 by APPWT, an effect absent with APPK28A. The enzymatic activity of α-, β- and γ-secretases remained unchanged in cells expressing APPK28A. Similarly, APPK28A subcellular localization in early endosomes did not differ to APPWT. Finally, WT but not CBS mutant Aβ derived peptides bound to cholesterol-rich exosomes.ConclusionsTaken together, these data reveal a major role of the juxtamembrane region of APP in binding to cholesterol and accordingly in the regulation of APP processing. Binding of cholesterol to K28 could staple APP to the juxtamembrane region thereby permitting access to γ-secretase cleavage at positions 40-42. The APPK28 mutant would lie deeper in the membrane, facilitating the production of shorter Aβ peptides and unveiling this specific region as a novel target for reducing the production of toxic Aβ species.

How SIMS microscopy can be used in medicine

1992 ◽  
Vol 50 (2) ◽  
pp. 1602-1603
Author(s):  
Philippe Fragu
Keyword(s):  
Mass Spectrometry ◽  
Biomedical Applications ◽  
Secondary Ion Mass Spectrometry ◽  
Chemical Elements ◽  
Biological Applications ◽  
The Past ◽  
Potential Source ◽  
Secondary Ion ◽  
Chemical Integrity ◽  
Scientific Endeavour

The identification, localization and quantification of intracellular chemical elements is an area of scientific endeavour which has not ceased to develop over the past 30 years. Secondary Ion Mass Spectrometry (SIMS) microscopy is widely used for elemental localization problems in geochemistry, metallurgy and electronics. Although the first commercial instruments were available in 1968, biological applications have been gradual as investigators have systematically examined the potential source of artefacts inherent in the method and sought to develop strategies for the analysis of soft biological material with a lateral resolution equivalent to that of the light microscope. In 1992, the prospects offered by this technique are even more encouraging as prototypes of new ion probes appear capable of achieving the ultimate goal, namely the quantitative analysis of micron and submicron regions. The purpose of this review is to underline the requirements for biomedical applications of SIMS microscopy.Sample preparation methodology should preserve both the structural and the chemical integrity of the tissue.

Contributory Factors for Obesity in Elderly: Review of the Literature

2019 ◽  
Vol 15 (3) ◽  
Author(s):  
Nur Raihan Ismail ◽  
Noor Aman Hamid
Keyword(s):  
English Language ◽  
The Elderly ◽  
Dietary Factors ◽  
Health Concern ◽  
Cross Sectional ◽  
Contributory Factors ◽  
The Past ◽  
Prevalence Of Obesity ◽  
Program Intervention ◽  
Future Education

Introduction: The prevalence of obesity has been rising, adding to morbidity and mortality. As the proportion of elderly aged 60 years and above grows, so too the prevalence of obesity among this population. Obesity in the elderly is a rapidly growing public health concern as it contributes to significant changes in the health of older people. Objective: This review aims to assess the contributory factors for obesity in the elderly over the past decade. Methods: A literature search was conducted. The search was restricted to articles written in the English language published from 2008 to 2018. Qualitative studies were excluded. Results: A total of 19 full articles were retrieved, of which 18 cross-sectional and one cohort were included. The contributory factors were divided into three components: (a) socio demographic characteristics, (b) medical history and dietary factors and (c) environmental factors. Conclusions: This review informs an emerging knowledge regarding contributory factors for obesity and has implications for future education and program intervention in fighting obesity in the elderly.

Mass Spectrometry Techniques: Principles and Practices for Quantitative Proteomics

2020 ◽  
Vol 21 ◽  
Author(s):  
Rocco J. Rotello ◽  
Timothy D. Veenstra
Keyword(s):  
Mass Spectrometry ◽  
Quantitative Proteomics ◽  
Protein Identification ◽  
Dynamic Nature ◽  
Complete Coverage ◽  
The Past ◽  
Proteome Level ◽  
A Cell ◽  
Quantitative Changes ◽  
Made In

: In the current omics-age of research, major developments have been made in technologies that attempt to survey the entire repertoire of genes, transcripts, proteins, and metabolites present within a cell. While genomics has led to a dramatic increase in our understanding of such things as disease morphology and how organisms respond to medications, it is critical to obtain information at the proteome level since proteins carry out most of the functions within the cell. The primary tool for obtaining proteome-wide information on proteins within the cell is mass spectrometry (MS). While it has historically been associated with the protein identification, developments over the past couple of decades have made MS a robust technology for protein quantitation as well. Identifying quantitative changes in proteomes is complicated by its dynamic nature and the inability of any technique to guarantee complete coverage of every protein within a proteome sample. Fortunately, the combined development of sample preparation and MS methods have made it capable to quantitatively compare many thousands of proteins obtained from cells and organisms.

scholarly journals Sensitive and quantitative detection of MHC-I displayed neoepitopes using a semi-automated workflow and TOMAHAQ mass spectrometry

2021 ◽  
pp. 100108
Author(s):  
Samuel B. Pollock ◽  
Christopher M. Rose ◽  
Martine Darwish ◽  
Romain Bouziat ◽  
Lélia Delamarre ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Quantitative Detection ◽  
Mhc I

Matrix-assisted laser desorption ionisation (MALDI) mass spectrometry (MS): basics and clinical applications

2020 ◽  
Vol 58 (6) ◽  
pp. 883-896 ◽  
Author(s):  
Muhammad Zubair Israr ◽  
Dennis Bernieh ◽  
Andrea Salzano ◽  
Shabana Cassambai ◽  
Yoshiyuki Yazaki ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Laser Desorption ◽  
Maldi Mass Spectrometry ◽  
Clinical Applications ◽  
Clinical Diagnostics ◽  
Maldi Ms ◽  
Therapeutic Drug ◽  
The Impact ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

AbstractBackgroundMatrix-assisted laser desorption ionisation (MALDI) mass spectrometry (MS) has been used for more than 30 years. Compared with other analytical techniques, it offers ease of use, high throughput, robustness, cost-effectiveness, rapid analysis and sensitivity. As advantages, current clinical techniques (e.g. immunoassays) are unable to directly measure the biomarker; rather, they measure secondary signals. MALDI-MS has been extensively researched for clinical applications, and it is set for a breakthrough as a routine tool for clinical diagnostics.ContentThis review reports on the principles of MALDI-MS and discusses current clinical applications and the future clinical prospects for MALDI-MS. Furthermore, the review assesses the limitations currently experienced in clinical assays, the advantages and the impact of MALDI-MS to transform clinical laboratories.SummaryMALDI-MS is widely used in clinical microbiology for the screening of microbial isolates; however, there is scope to apply MALDI-MS in the diagnosis, prognosis, therapeutic drug monitoring and biopsy imaging in many diseases.OutlookThere is considerable potential for MALDI-MS in clinic as a tool for screening, profiling and imaging because of its high sensitivity and specificity over alternative techniques.

scholarly journals An Investigation of the Wild Rat Crown Incisor as an Indicator of Lead (Pb) Exposure Using Inductively Couple Plasma Mass Spectrometry (ICP-MS) and Laser Ablation ICP-MS

2021 ◽  
Vol 18 (2) ◽  
pp. 767
Author(s):  
Andrew Kataba ◽  
Shouta M. M. Nakayama ◽  
Hokuto Nakata ◽  
Haruya Toyomaki ◽  
Yared B. Yohannes ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Laser Ablation ◽  
Inductively Couple Plasma ◽  
Health Concern ◽  
Sprague Dawley ◽  
Rat Incisor ◽  
Sprague Dawley Rats ◽  
Icp Ms ◽  
Plasma Mass Spectrometry ◽  
Pb Exposure

Lead (Pb) is a metal toxicant of great public health concern. The present study investigated the applicability of the rat incisor in Pb exposure screening. The levels of lead in teeth (Pb-T) in the crown and root of incisors in laboratory Pb-exposed Sprague Dawley rats were quantified using inductively coupled plasma mass spectrometry (ICP-MS). The crown accumulated much Pb-T than the root of the Sprague Dawley rat incisor. The levels of lead in blood (Pb-B) were positively correlated with the Pb-T in the crown and root incisors of the Sprague Dawley rats. As an application of the Pb-T crown results in experimental rats, we subsequently analyzed the Pb-T in the crown incisors of Pb-exposed wild rats (Rattus rattus) sampled from residential sites within varying distances from an abandoned lead–zinc mine. The Pb-T accumulation in the crown of incisors of R. rattus rats decreased with increased distance away from the Pb–Zn mine. Furthermore, the Pb-T was strongly correlated (r = 0.85) with the Pb levels in the blood. Laser ablation ICP-MS Pb-T mappings revealed a homogenous distribution of Pb in the incisor with an increased intensity of Pb-T localized in the tip of the incisor crown bearing an enamel surface in both Sprague Dawley and R. rattus rats. These findings suggest that Pb-T in the crown incisor may be reflective of the rat’s environmental habitat, thus a possible indicator of Pb exposure.

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