Anticoagulants affect matrix metalloproteinase 9 levels in blood samples of stroke patients and healthy controls.

OBJECTIVE

Matrix metalloproteinase-9 (MMP-9) represents a promising marker for acute stroke management. In clinical studies MMP-9 has been quantified by ELISA using differing protocols. We aimed to establish a valid protocol by evaluation of preanalytics.

METHODS

Blood from stroke patients (n=28) and healthy controls (n=28) was drawn into tubes containing different anticoagulants (EDTA, citrate, lithium-heparin (heparin) and heparin with proteinase inhibitors) and processed after 0, 60 and 240 min. MMP-9 plasma protein and mRNA from mononuclear leukocytes were determined.

RESULTS

In regard to anticoagulants used, samples showed different MMP-9 protein baseline values and kinetics. Stable MMP-9 protein concentrations were only measured from EDTA samples. Particularly in samples with proteinase inhibitors protein and mRNA concentrations increased over time. Kinetics did not differ between patients and controls.

CONCLUSIONS

Preanalytics plays a key role for determination of MMP-9. EDTA seems to be a valid anticoagulant for MMP-9 protein measurement.