A targeted proteomic multiplex CSF assay identifies increased malate dehydrogenase and other neurodegenerative biomarkers in individuals with Alzheimer's disease pathology

Transl Psychiatry. 2016 Nov 15;6(11):e952. doi: 10.1038/tp.2016.194.

Abstract

Alzheimer's disease (AD) is the most common cause of dementia. Biomarkers are required to identify individuals in the preclinical phase, explain phenotypic diversity, measure progression and estimate prognosis. The development of assays to validate candidate biomarkers is costly and time-consuming. Targeted proteomics is an attractive means of quantifying novel proteins in cerebrospinal and other fluids, and has potential to help overcome this bottleneck in biomarker development. We used a previously validated multiplexed 10-min, targeted proteomic assay to assess 54 candidate cerebrospinal fluid (CSF) biomarkers in two independent cohorts comprising individuals with neurodegenerative dementias and healthy controls. Individuals were classified as 'AD' or 'non-AD' on the basis of their CSF T-tau and amyloid Aβ1-42 profile measured using enzyme-linked immunosorbent assay; biomarkers of interest were compared using univariate and multivariate analyses. In all, 35/31 individuals in Cohort 1 and 46/36 in Cohort 2 fulfilled criteria for AD/non-AD profile CSF, respectively. After adjustment for multiple comparisons, five proteins were elevated significantly in AD CSF compared with non-AD CSF in both cohorts: malate dehydrogenase; total APOE; chitinase-3-like protein 1 (YKL-40); osteopontin and cystatin C. In an independent multivariate orthogonal projection to latent structures discriminant analysis (OPLS-DA), these proteins were also identified as major contributors to the separation between AD and non-AD in both cohorts. Independent of CSF Aβ1-42 and tau, a combination of these biomarkers differentiated AD and non-AD with an area under curve (AUC)=0.88. This targeted proteomic multiple reaction monitoring (MRM)-based assay can simultaneously and rapidly measure multiple candidate CSF biomarkers. Applying this technique to AD we demonstrate differences in proteins involved in glucose metabolism and neuroinflammation that collectively have potential clinical diagnostic utility.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Alzheimer Disease / cerebrospinal fluid*
  • Alzheimer Disease / diagnosis
  • Apolipoproteins E / cerebrospinal fluid
  • Biomarkers / cerebrospinal fluid*
  • Chitinase-3-Like Protein 1 / cerebrospinal fluid
  • Cohort Studies
  • Cystatin C / cerebrospinal fluid
  • Female
  • Humans
  • Malate Dehydrogenase / cerebrospinal fluid*
  • Male
  • Mental Status Schedule
  • Middle Aged
  • Multiplex Polymerase Chain Reaction*
  • Neurodegenerative Diseases / cerebrospinal fluid*
  • Neurodegenerative Diseases / diagnosis
  • Osteopontin / cerebrospinal fluid
  • Predictive Value of Tests
  • Proteomics*
  • Statistics as Topic
  • Sweden

Substances

  • Apolipoproteins E
  • Biomarkers
  • CHI3L1 protein, human
  • CST3 protein, human
  • Chitinase-3-Like Protein 1
  • Cystatin C
  • SPP1 protein, human
  • Osteopontin
  • Malate Dehydrogenase