Background and aim of the study: Reversal of myocardial collagen gene expression was examined in parallel to left ventricular reverse remodeling after surgical correction of experimental aortic stenosis.
Methods: A standard growing sheep model (age at baseline 6-8 months) was used. Measurements were performed at baseline (point A) when inducing left ventricular hypertrophy (LVH) through supracoronary banding, at 8.3 +/- 1.0 months later at surgical correction (point B), and after another 10.1 +/- 2.0 months during final examinations (point C). Gene expression for collagen I and III was also studied.
Results: Left ventricular function was stable throughout the study. The left ventricular mass index (LVMI) was 82 +/- 21 g/m2 at point A, 150 +/- 33 g/m2 at B, and 78 +/- 18 g/m2 at C (p <0.01). Myocardial fiber diameter was 11.3 +/- 0.8, 15.9 +/- 1.2 and 11.4 +/- 1 microm at points A, B and C, respectively (p <0.01). Protein expression for collagen I was 0.71 +/- 0.2 (at A), 1.13 +/- 0.3 (at B) and 0.85 +/- 0.4 (at C) (p <0.01), while that for collagen III was 0.72 +/- 0.4 (at A), 1.26 +/- 0.8 (at B) and 0.83 +/- 0.3 (at C) (p <0.01). There was a significant correlation between changes in LVMI and myocardial collagen expression.
Conclusion: Complete reverse remodeling with regression of LVH and myocardial collagen protein expression can be anticipated after surgical correction of experimental aortic stenosis.