title: Assessment of endothelin and copeptin as biomarkers for vasovagal syncope.
abstract: BACKGROUND
  The diagnosis of vasovagal syncope continues to be difficult despite the use of accurate histories, tilt testing and implantable loop recorders. A circulating biomarker might be useful to facilitate diagnoses. Both endothelin-1 and vasopressin are increased during positive tilt tests resulting in syncope. Copeptin is a stable cleavage product of vasopressin formation. We conducted a pilot study to assess the utility of endothelin-1 and copeptin as circulating biomarkers of vasovagal syncope.
  
  
  METHODS
  Three populations were studied: syncope patients, epilepsy patients and controls. Vasovagal syncope diagnosis was ascertained with the Calgary Syncope Score and epilepsy diagnosis was confirmed with EEG. Plasma levels of endothelin-1 were measured using by ELISA and copeptin levels were determined using an EIA kit.
  
  
  RESULTS
  Asymptomatic control subjects had mean age 35 ± 11 years (7/22 male); epileptic subjects had mean age 32 ± 7 years (4/15 male); and syncope subjects had mean age 33 ± 16 years (4 of 21 male). Circulating plasma levels of endothelin-1 and copeptin were no different among the three groups. Mean concentrations of endothelin-1 were as follows: syncope, 23 ± 32 pg/mL; controls, 21 ± 17 pg/mL; and epileptics, 18 ± 12 pg/mL. Mean concentrations of copeptin were as follows: syncope, 1·29 ± 0·79 ng/mL; controls, 1·25 ± 0·79 ng/mL; and seizures, 1·23 ± 0·45 ng/mL. There were no significant correlations between syncope frequency and copeptin or endothelin-1 levels.
  
  
  CONCLUSIONS
  Circulating plasma endothelin-1 and copeptin levels are not significantly different among populations of controls, syncope patients and seizure patients.
authors.affiliation: Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada.
authors.forename: Arjun
authors.initials: A
authors.lastname: Rash
authors.affiliation: Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada.
authors.forename: Maureen
authors.initials: M
authors.lastname: McRae
authors.affiliation: Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.
authors.forename: Jaleh
authors.initials: J
authors.lastname: Fatehi
authors.affiliation: Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada.
authors.forename: Deborah
authors.initials: D
authors.lastname: Richie
authors.affiliation: Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada.
authors.forename: Monica
authors.initials: M
authors.lastname: Solbiati
authors.affiliation: Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.
authors.forename: Neelan
authors.initials: N
authors.lastname: Pillay
authors.affiliation: Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada.
authors.forename: Annegret
authors.initials: A
authors.lastname: Ulke-Lemée
authors.affiliation: Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada.
authors.forename: Justin
authors.initials: J
authors.lastname: MacDonald
authors.affiliation: Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, AB, Canada.
authors.forename: Robert
authors.initials: R
authors.lastname: Sheldon
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D019332:Endothelin-1 / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D004827:Epilepsy / Q000097:blood; D005260:Female; D006020:Glycopeptides / Q000097:blood*; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D019462:Syncope, Vasovagal / Q000097:blood*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D019332:Endothelin-1; D006020:Glycopeptides; C048197:copeptins
keywords: Biomarkers; copeptin; diagnosis; endothelin; vasovagal syncope