Autonomic regulation of mechanical properties in porcine mitral valve cusps.
BACKGROUND
The presence of nerves in heart valves was first depicted decades ago and identified into subpopulations: sympathetic, parasympathetic. So valves are expected to be greatly affected by the autonomic nerves. However, few studies have focused on the regulation of heart valves by the autonomic nervous system.


OBJECTIVE
We sought to identify the role of the autonomic nervous system in the regulation of the mechanical properties of porcine mitral valve tissues.


METHODS
Mechanical properties of porcine mitral valve leaflets were evaluated in response to norepinephrine (NE) and acetylcholine (ACH), the main neurotransmitters. At the same time, phentolamine (Phent), metoprolol (Metop), atropine (Atrop) and endothelial denudation were added to the reactive system.


RESULTS
Under physiological conditions, the stiffness was not affected by endothelial denudation (p > 0.05). NE elevated the valve stiffness significantly per 10-fold increase in concentration (10(-6) vs 10(-7), p < 0.05; 10(-5) vs 10(-6), p < 0.05). This response was mitigated by Phent, Metop or endothelial denudation (p < 0.05), however, it was still increased significantly when compared to Controls (p < 0.05). ACH caused a decrease in stiffness accompanied by an increase in its concentration (significant change in stiffness per 10-fold increase in ACH concentration, 10(-6) vs Control, p < 0.05; 10(-5) vs 10(-6), p < 0.05), which were reversed by endothelial denudation and Atrop (p > 0.05 vs Control).


CONCLUSIONS
These findings highlight the role of the autonomic nervous system in the regulation of the mechanical properties of porcine mitral valve cusps, which underline the importance of autonomic nervous status for optimal valve function.
Department of Cardiac Surgery, Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, PRC.
Xiang
X
Hu
Qiang
Q
Zhao
Xiaofeng
X
Ye
D000109:Acetylcholine / Q000494:pharmacology; D058668:Adrenergic alpha-1 Receptor Antagonists / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D001021:Aortic Valve / Q000503:physiopathology; D001341:Autonomic Nervous System / Q000187:drug effects / Q000502:physiology*; D004547:Elastic Tissue / Q000502:physiology; D008943:Mitral Valve / Q000294:innervation / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology; D010646:Phentolamine / Q000494:pharmacology; D017981:Receptors, Neurotransmitter / Q000187:drug effects / Q000502:physiology; D013552:Swine; D059289:Vascular Stiffness / Q000187:drug effects / Q000502:physiology
D058668:Adrenergic alpha-1 Receptor Antagonists; D017981:Receptors, Neurotransmitter; D000109:Acetylcholine; D009638:Norepinephrine; D010646:Phentolamine