title: Abnormal lipopolysaccharide binding protein as marker of gastrointestinal inflammation in Parkinson disease.
abstract: OBJECTIVE
  An inflammation-driven model of PD has been proposed based on the endotoxin lipopolysaccaride (LPS), a potential source of inflammation in the gastrointestinal system linked to neurotoxicity. Systemic exposure to bacterial endotoxin (LPS) can be determined by measuring plasma LPS binding protein (LBP). We aimed to evaluate whether lipopolysaccharide binding protein (LBP) can be used to distinguish PD subjects from control subjects and to assess whether LBP levels correlate with PD disease severity.
  
  
  METHODS
  We measured plasma LBP (ng/ml) using an ELISA kit in 94 PD subjects of various stages and 97 control subjects. Disease severity was assessed using the UPDRS and Hoehn and Yahr staging. The LBP level between the PD and control groups was compared using analysis of covariance. Spearman correlation was used to explore the relationship between LBP level and disease severity.
  
  
  RESULTS
  The mean LBP level in PD subjects (n = 94) was significantly different from control subjects (n = 95, p = 0.018). In PD subjects, we did not find a correlation between mean LBP level and disease severity.
  
  
  CONCLUSIONS
  Our data suggests that LBP is one GI biomarker related to LPS induced neurotoxicity. However, there was significant variability in LBP levels within the PD and control groups, limiting its utility as a stand-alone biomarker. This study supports the role of LPS induced neurotoxicity in PD and further exploration of this pathway may be useful in developing sensitive and specific biomarkers for PD.
authors.affiliation: Department of Neurological Sciences, Rush University Medical Center Chicago, IL, USA.
authors.forename: Gian D
authors.initials: GD
authors.lastname: Pal
authors.affiliation: Department of Internal Medicine, Section of Gastroenterology, Rush University Medical Center Chicago, IL, USA.
authors.forename: Maliha
authors.initials: M
authors.lastname: Shaikh
authors.affiliation: Department of Internal Medicine, Section of Gastroenterology, Rush University Medical Center Chicago, IL, USA.
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Forsyth
authors.affiliation: Department of Neurological Sciences, Rush University Medical Center Chicago, IL, USA.
authors.forename: Bichun
authors.initials: B
authors.lastname: Ouyang
authors.affiliation: Department of Internal Medicine, Section of Gastroenterology, Rush University Medical Center Chicago, IL, USA.
authors.forename: Ali
authors.initials: A
authors.lastname: Keshavarzian
authors.affiliation: Department of Neurological Sciences, Rush University Medical Center Chicago, IL, USA.
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Shannon
keywords: Parkinson disease; biomarker; gastrointestinal; lipopolysaccharide