Soluble urokinase-type plasminogen activator receptor forms in plasma as markers of atherosclerotic plaque vulnerability.
OBJECTIVE
: To test if circulating forms of the soluble urokinase-type plasminogen activator receptor (suPAR) are potential biomarkers of plaque vulnerability.


METHODS
: Plasma concentrations of suPAR(I-III), suPAR(II-III) and uPAR(I) were measured by time-resolved fluorescence immunoassays in Caucasian patients operated for symptomatic carotid atherosclerosis (n=255). Local suPAR release from plaques into the circulation was assessed in plasma passing retrogradely over the plaque in the carotid artery, collected during surgery (n=7).


RESULTS
: The suPAR(I-III) (P=0.03) and suPAR(II-III) (P=0.006) concentrations were higher after ischemic strokes and transient ischemic attacks, i.e., clinical subgroups associated with poorer prognosis and a less stable plaque phenotype, than after amaurosis fugax. Slightly elevated suPAR(I-III) levels were found in plasma from the carotid lesion. However, refuting the hypothesis, the concentrations of the suPAR forms were not higher in patients with short intervals between clinical event and blood sampling compared with those with long intervals. Age, inflammatory markers and diabetes were confounding factors independently associated with suPAR forms.


CONCLUSIONS
: Circulating suPAR forms are probably not useful biomarkers of atherosclerotic plaque vulnerability.
Olson
Fredrik J
FJ
Center for Cardiovascular and Metabolic Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden. fredrik.olson@wlab.gu.se
Thurison
Tine
T
Ryndel
Mikael
M
Høyer-Hansen
Gunilla
G
Fagerberg
Björn
B
D000368:Aged; D050197:Atherosclerosis / Q000097:blood / Q000473:pathology; D015415:Biomarkers / Q000097:blood*; D016893:Carotid Stenosis / Q000473:pathology*; D005260:Female; D006801:Humans; D057230:Limit of Detection; D008297:Male; D020033:Protein Isoforms / Q000097:blood*; D055293:Receptors, Urokinase Plasminogen Activator / Q000097:blood*; D012307:Risk Factors; D020521:Stroke / Q000097:blood
D015415:Biomarkers; D020033:Protein Isoforms; D055293:Receptors, Urokinase Plasminogen Activator