Urine dicarboxylic acids change in pre-symptomatic Alzheimer's disease and reflect loss of energy capacity and hippocampal volume

PLoS One. 2020 Apr 16;15(4):e0231765. doi: 10.1371/journal.pone.0231765. eCollection 2020.


Non-invasive biomarkers will enable widespread screening and early diagnosis of Alzheimer's disease (AD). We hypothesized that the considerable loss of brain tissue in AD will result in detection of brain lipid components in urine, and that these will change in concert with CSF and brain biomarkers of AD. We examined urine dicarboxylic acids (DCA) of carbon length 3-10 to reflect products of oxidative damage and energy generation or balance that may account for changes in brain function in AD. Mean C4-C5 DCAs were lower and mean C7-C10 DCAs were higher in the urine from AD compared to cognitively healthy (CH) individuals. Moreover, mean C4-C5 DCAs were lower and mean C7-C9 were higher in urine from CH individuals with abnormal compared to normal CSF amyloid and Tau levels; i.e., the apparent urine changes in AD also appeared to be present in CH individuals that have CSF risk factors of early AD pathology. In examining the relationship between urine DCAs and AD biomarkers, we found short chain DCAs positively correlated with CSF Aβ42, while C7-C10 DCAs negatively correlated with CSF Aβ42 and positively correlated with CSF Tau levels. Furthermore, we found a negative correlation of C7-C10 DCAs with hippocampal volume (p < 0.01), which was not found in the occipital volume. Urine measures of DCAs have an 82% ability to predict cognitively healthy participants with normal CSF amyloid/Tau. These data suggest that urine measures of increased lipoxidation and dysfunctional energy balance reflect early AD pathology from brain and CSF biomarkers. Measures of urine DCAs may contribute to personalized healthcare by indicating AD pathology and may be utilized to explore population wellness or monitor the efficacy of therapies in clinical trials.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Alzheimer Disease / diagnosis*
  • Alzheimer Disease / diagnostic imaging
  • Alzheimer Disease / pathology
  • Amyloid beta-Peptides / cerebrospinal fluid*
  • Asymptomatic Diseases
  • Biomarkers / cerebrospinal fluid
  • Biomarkers / urine
  • Cognitive Dysfunction / diagnosis
  • Cognitive Dysfunction / diagnostic imaging
  • Dicarboxylic Acids / chemistry
  • Dicarboxylic Acids / urine*
  • Female
  • Gas Chromatography-Mass Spectrometry
  • Hippocampus / pathology*
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Multivariate Analysis
  • Risk Factors
  • tau Proteins / cerebrospinal fluid*


  • Amyloid beta-Peptides
  • Biomarkers
  • Dicarboxylic Acids
  • tau Proteins

Grants and funding

JMP is employed by and receives salary from Cipher Biostatistics & Reporting. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.