TY - JOUR
T1 - Distinct Expression of Nonmuscle Myosin IIB in Pulmonary Arteries of Patients With Aortic Stenosis vs Insufficiency Undergoing a Ross Procedure
AU - Emmott, Alexander
AU - Hertig, Vanessa
AU - Bergeron, Alexandre
AU - Villeneuve, Louis
AU - Lefebvre, Laurence
AU - Leask, Richard L.
AU - Calderone, Angelino
AU - El-Hamamsy, Ismail
N1 - Publisher Copyright:
© 2020 Canadian Cardiovascular Society
PY - 2021/1
Y1 - 2021/1
N2 - Background: Clinical studies have revealed a greater risk of pulmonary autograft dilation after the Ross procedure in patients with preoperative aortic insufficiency (AI). The present study examined whether the morphologic, biomechanical, and cellular properties of the pulmonary artery (PA) from patients with AI were phenotypically different compared with patients diagnosed with aortic stenosis (AS). Methods: PA segments were harvested from patients undergoing the Ross procedure for AS (n = 16) and AI (n = 6). Preoperative aortic annulus was significantly larger (P < 0.05) in patients with AI (28.5 ± 1.8 mm) vs AS (22.8 ± 1.2 mm). Morphologic, biomechanical, and cellular phenotypes of the PA were analyzed. Results: Collagen and elastin content in the media of the PA wall were similar in patients with AS and AI. Elastic modulus and energy loss of the PA were not significantly different between the groups. In the media of the PA, expression of a panel of vascular smooth muscle cell–specific proteins were similar in patients with AS and AI. In contrast, nonmuscle myosin IIB protein levels in the PA of AS patients were significantly higher compared with AI patients, and immunofluorescence identified staining in α-smooth muscle actin–positive vascular smooth muscle cells. Conclusions: Despite similar morphological and biomechanical properties, the disparate expression of nonmuscle myosin IIB protein distinguishes the PA of patients with AI from patients with AS. The biological role in vascular smooth muscle cells and the potential contribution of nonmuscle myosin IIB to pulmonary autograft dilation in a subset of AI patients after the Ross procedure remain to be determined.
AB - Background: Clinical studies have revealed a greater risk of pulmonary autograft dilation after the Ross procedure in patients with preoperative aortic insufficiency (AI). The present study examined whether the morphologic, biomechanical, and cellular properties of the pulmonary artery (PA) from patients with AI were phenotypically different compared with patients diagnosed with aortic stenosis (AS). Methods: PA segments were harvested from patients undergoing the Ross procedure for AS (n = 16) and AI (n = 6). Preoperative aortic annulus was significantly larger (P < 0.05) in patients with AI (28.5 ± 1.8 mm) vs AS (22.8 ± 1.2 mm). Morphologic, biomechanical, and cellular phenotypes of the PA were analyzed. Results: Collagen and elastin content in the media of the PA wall were similar in patients with AS and AI. Elastic modulus and energy loss of the PA were not significantly different between the groups. In the media of the PA, expression of a panel of vascular smooth muscle cell–specific proteins were similar in patients with AS and AI. In contrast, nonmuscle myosin IIB protein levels in the PA of AS patients were significantly higher compared with AI patients, and immunofluorescence identified staining in α-smooth muscle actin–positive vascular smooth muscle cells. Conclusions: Despite similar morphological and biomechanical properties, the disparate expression of nonmuscle myosin IIB protein distinguishes the PA of patients with AI from patients with AS. The biological role in vascular smooth muscle cells and the potential contribution of nonmuscle myosin IIB to pulmonary autograft dilation in a subset of AI patients after the Ross procedure remain to be determined.
UR - http://www.scopus.com/inward/record.url?scp=85089454455&partnerID=8YFLogxK
U2 - 10.1016/j.cjca.2020.02.074
DO - 10.1016/j.cjca.2020.02.074
M3 - Article
C2 - 32544488
AN - SCOPUS:85089454455
SN - 0828-282X
VL - 37
SP - 47
EP - 56
JO - Canadian Journal of Cardiology
JF - Canadian Journal of Cardiology
IS - 1
ER -