Synaptic proteins predict cognitive decline in Alzheimer's disease and Lewy body dementia

Alzheimers Dement. 2016 Nov;12(11):1149-1158. doi: 10.1016/j.jalz.2016.04.005. Epub 2016 May 22.


Introduction: Our objective was to compare the levels of three synaptic proteins involved in different steps of the synaptic transmission: Rab3A, SNAP25, and neurogranin, in three common forms of dementia: Alzheimer's disease (AD), dementia with Lewy bodies (DLB), and Parkinson's disease dementia.

Methods: A total of 129 postmortem human brain samples were analyzed in brain regional specific manner exploring their associations with morphologic changes and cognitive decline.

Results: We have observed robust changes reflecting synaptic dysfunction in all studied dementia groups. There were significant associations between the rate of cognitive decline and decreased levels of Rab3 in DLB in the inferior parietal lobe and SNAP25 in AD in the prefrontal cortex. Of particular note, synaptic proteins significantly discriminated between dementia cases and controls with over 90% sensitivity and specificity.

Discussion: Our findings suggest that the proposition that synaptic markers can predict cognitive decline in AD, should be extended to Lewy body diseases.

Keywords: Alzheimer's disease; Cognitive impairment; Dementia with Lewy bodies; Neurogranin; Parkinson's disease with dementia; Rab3A; SNAP25; Synaptic dysfunction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Alzheimer Disease / diagnosis
  • Alzheimer Disease / metabolism*
  • Alzheimer Disease / pathology
  • Alzheimer Disease / psychology
  • Biomarkers / metabolism
  • Brain / metabolism*
  • Brain / pathology
  • Cognitive Dysfunction / diagnosis
  • Cognitive Dysfunction / etiology
  • Cognitive Dysfunction / metabolism*
  • Cognitive Dysfunction / pathology
  • Cohort Studies
  • Diagnosis, Differential
  • Disease Progression
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Humans
  • Immunoblotting
  • Immunohistochemistry
  • Lewy Body Disease / diagnosis
  • Lewy Body Disease / metabolism*
  • Lewy Body Disease / pathology
  • Lewy Body Disease / psychology
  • Male
  • Mental Status and Dementia Tests
  • Multivariate Analysis
  • Nerve Tissue Proteins / metabolism*
  • Sensitivity and Specificity
  • Synapses / metabolism


  • Biomarkers
  • Nerve Tissue Proteins