title: Plasma apolipoprotein A1 associates with age at onset and motor severity in early Parkinson's disease patients.
abstract: BACKGROUND
  Development of robust plasma-based biomarkers in Parkinson's disease (PD) could lead to new approaches for identifying those at risk for PD and developing novel therapies. Here, we validate plasma apolipoprotein A1 (ApoA1) as a correlate of age at onset and motor severity in PD.
  
  
  METHODS
  Plasma ApoA1 and high-density lipoprotein at baseline, 6 months, and 12 months were measured in 254 research volunteers (154 patients with PD and 100 normal controls) enrolled in the Parkinson's Progression Markers Initiative (PPMI) study.
  
  
  RESULTS
  Lower baseline plasma ApoA1 levels associate with an earlier age at PD onset in early-stage, drug-naïve PPMI PD patients (P = 0.023). Moreover, lower baseline ApoA1 levels trend toward association with worse motor severity in PPMI PD patients (p = 0.080). Over 12 months of follow-up, plasma ApoA1 levels do not predict motor decline in the PPMI PD cohort. Finally, a meta-analysis of five PD cohorts encompassing >1,000 patients confirms significant association of lower plasma ApoA1 with earlier age at PD onset (P < 0.001) and greater motor severity (P < 0.001).
  
  
  CONCLUSIONS
  Our results confirm the previously reported association of lower plasma ApoA1 levels with two clinical features suggesting poorer dopaminergic system integrity-earlier age at PD onset and greater motor severity-in early-stage, drug-naïve PD patients. This is the first report of a plasma-based biomarker evaluated in the PPMI study. Future investigations are warranted evaluating plasma ApoA1 as a longitudinal correlate of disease progression as well as investigating the potential of ApoA1 as a therapeutic target in PD.
authors.affiliation: Department of Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Christine R
authors.initials: CR
authors.lastname: Swanson
authors.affiliation: Department of Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Yosef
authors.initials: Y
authors.lastname: Berlyand
authors.affiliation: Department of Biostatistics and Epidemiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Sharon X
authors.initials: SX
authors.lastname: Xie
authors.affiliation: Department of Neurology, Columbia University College of Physicians and Surgeons, New York, New York, USA.
authors.forename: Roy N
authors.initials: RN
authors.lastname: Alcalay
authors.affiliation: Department of Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Lama M
authors.initials: LM
authors.lastname: Chahine
authors.affiliation: Department of Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Alice S
authors.initials: AS
authors.lastname: Chen-Plotkin
mesh_terms: D017668:Age of Onset; D000368:Aged; D016632:Apolipoprotein A-I / Q000097:blood*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007391:International Cooperation; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D010300:Parkinson Disease / Q000097:blood* / Q000503:physiopathology*; D012720:Severity of Illness Index; D013223:Statistics as Topic; D013997:Time Factors
chemical_list: D016632:Apolipoprotein A-I; D008055:Lipids
keywords: Parkinson's disease; apolipoprotein A1; biomarker