We have previously reported (Circulation 94:162, 1996) that EC angiotensin converting enzyme (ACE) activity increases following coronary arterial bypass grafting, in vivo. To investigate possible mechanisms of this effect, we studied the role of the high potassium (HP) and low potassium (LP) containing Plegisol cardioplegic solutions on EC ACE activity, in 24-well plates monolayers, in vitro, using two ontogenetically different EC lines: bovine aortic EC (BAEC) and bovine pulmonary arterial EC (BPAEC). EC were exposed to M199 cell culture medium (control), HP or LP (20% in M199) for 1, 2 or 4 h 28°C. After the cold cardioplegic incubation period, ACE activity was measured using the synthetic ACE substrate, 3H-benzoyl-Phe-Ala-Pro (0 3μCi incubated in 600μl Earle's balanced salt solution for 45 min at 37°C). In BPAEC, ACE activity significantly increased after 1 (1.39 v. 2 65 U/well), 2 (0.23 v. 0.35 U/well) and 4 h (0.45 v 0.56 U/well) exposure to LP, as well as after 1 (1.39 v. 1.83 U/well), 2 (0.23 v. 0.26 U/well), but not 4 h (0.45 v. 0.3 U/well) exposure to HP. In BAEC, small increases in ACE activity were observed only after 2 (0.04 v. 0.1 U/well) and 4 h exposure to LP (0.144 v 0.181 U/well) and 2h exposure to HP (0.04 v. 0.069 U/well). We conclude that ontogenetically different EC respond differently to cardioplegic solutions, in culture.
|Publication status||Published - Dec 1 1997|
ASJC Scopus subject areas
- Molecular Biology