Mice expressing either a soluble form of ACE (ACE 2/2) or mice with somatic ACE expression restricted to the liver and kidney (ACE 3/3) on an ApoEx2212;/x2212; background were placed on a standard chow or Western diet for 6 months. Atherosclerotic lesion area in the ACE 2/2 mice was significantly lower than that seen in the ACE 3/3 mice. However, these animals also had significantly lower blood pressure and reduced plasma ACE activity which precluded establishing a specific causal relationship between absent tissue ACE activity and decreased atherosclerotic lesion extent. Therefore, we studied the ACE 3/3 mice which are normotensive and lack vascular ACE expression. In the ACE 3/3 animals, atherosclerotic lesion area was not different from wild type controls despite reduced plasma ACE activity.
We concluded that under these experimental conditions, expression of ACE in the arterial wall is not required for atherosclerotic lesion formation.