Prolonged stability of endogenous cardiotrophin-1 in whole blood

Cardiotrophin-1 (CT-1) is a recently identified cytokine of the interleukin -6 (IL-6) family that signals through the gp130 signalling pathway. CT-1 ma y be of central importance to the pathogenesis of ventricular remodelling i n patients with acute myocardial infarction (AMI) and therefore have clinic al value in the identification of patients with impaired ventricular functi on. Central to the clinical use of CT-1 is in the in vitro stability of the peptide. Twelve subjects were recruited. A total of 25 mt of peripheral ve nous blood was collected into chilled polypropylene tubes containing EDTA a nd aprotinin and divided into 5 aliquots. One sample was spun in a prerefri gerated centrifuge (4 degreesC) at 3,000 rpm for 10 minutes and plasma sepa rated and frozen at -70 degreesC immediately. Remaining samples were stored for 24 and 48 hours at room temperature or on ice. CT-1 in extracted plasm a specimens was measured with a competitive chemiluminescent assay. The con centration of CT-1 in samples stored optimally was 43.1 +/- 6.05 fmol/mL, C T-1 levels for storage at room temperature compared with ice at the remaini ng time points were as follows: 24 hours, 41.5 +/- 5.76 v 37.5 +/- 8.66; an d 48 hours, 42.6 +/- 6.28 v 41.0 +/- 5.42 fmol/mL, There were no significan t changes in concentrations of CT-1 stored optimally or kept for up to 48 h ours in aliquots of whole blood at room temperature or on ice. We conclude that CT-1 is stable in specimens of whole blood treated with EDTA and aprot inin and stored for up to 48 hours at room temperature or on ice, hence per mitting its development in the routine clinical investigation of patients w ith heart failure. Copyright (C) 2001 by W.B. Saunders Company.