Calcium-activated potassium channel family in coronary artery bypass grafts

Wen-Tao Sun; Hai-Tao Hou; Huan-Xin Chen; Hong-Mei Xue; Jun Wang; Guo-Wei He; Qin Yang

doi:10.1016/j.jtcvs.2019.11.016

Calcium-activated potassium channel family in coronary artery bypass grafts

J Thorac Cardiovasc Surg. 2021 May;161(5):e399-e409. doi: 10.1016/j.jtcvs.2019.11.016. Epub 2019 Nov 28.

Authors

Wen-Tao Sun¹, Hai-Tao Hou¹, Huan-Xin Chen¹, Hong-Mei Xue¹, Jun Wang¹, Guo-Wei He², Qin Yang³

Affiliations

¹ Center for Basic Medical Research & Department of Cardiovascular Surgery, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, China.
² Center for Basic Medical Research & Department of Cardiovascular Surgery, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, China; School of Pharmacy, Wannan Medical College, Wuhu, Anhui, China; Department of Surgery, Oregon Health and Science University, Portland, Ore.
³ Center for Basic Medical Research & Department of Cardiovascular Surgery, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, China. Electronic address: qyanghk@163.com.

PMID: 31928817
DOI: 10.1016/j.jtcvs.2019.11.016

Abstract

Objectives: We examined the expression, distribution, and contribution to vasodilatation of the calcium-activated potassium (K_Ca) channel family in the commonly used coronary artery bypass graft internal thoracic artery (ITA) and saphenous vein (SV) to understand the role of large conductance K_Ca (BK_Ca), intermediate-conductance K_Ca (IK_Ca), and small-conductance K_Ca (SK_Ca) channel subtypes in graft dilating properties determined by endothelium-smooth muscle interaction that is essential to the postoperative performance of the graft.

Methods: Real-time polymerase chain reaction and western blot were employed to detect the messenger RNA and protein level of K_Ca channel subtypes. Distribution of K_Ca channel subtypes was examined by immunohistochemistry. K_Ca subtype-mediated vasorelaxation was studied using wire myography.

Results: Both ITA and SV express all K_Ca channel subtypes with each subtype distributed in both endothelium and smooth muscle. ITA and SV do not differ in the overall expression level of each K_Ca channel subtype, corresponding to comparable relaxant responses to respective subtype activators. In ITA, BK_Ca is more abundantly expressed in smooth muscle than in endothelium, whereas SK_Ca exhibits more abundance in the endothelium. In comparison, SV shows even distribution of K_Ca channel subtypes in the 2 layers. The BK_Ca subtype in the K_Ca family plays a significant role in vasodilatation of ITA, whereas its contribution in SV is quite limited.

Conclusions: K_Ca family is abundantly expressed in ITA and SV. There are differences between these 2 grafts in the abundance of K_Ca channel subtypes in the endothelium and the smooth muscle. The significance of the BK_Ca subtype in vasodilatation of ITA may suggest the potential of development of BK_Ca modulators for the prevention and treatment of ITA spasm during/after coronary artery bypass graft surgery.

Keywords: calcium-activated potassium channels; coronary artery bypass graft; internal mammary artery; saphenous vein.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Coronary Artery Bypass
Endothelium, Vascular / metabolism*
Humans
Immunohistochemistry
Mammary Arteries / metabolism*
Mammary Arteries / transplantation
Muscle, Smooth, Vascular / metabolism*
Myography
Potassium Channels, Calcium-Activated / biosynthesis*
Potassium Channels, Calcium-Activated / metabolism
Saphenous Vein / metabolism*
Saphenous Vein / transplantation
Vasodilation / physiology*

Substances

Potassium Channels, Calcium-Activated