Engineered Cardiac Pacemaker Nodes Created by TBX18 Gene Transfer Overcome Source–Sink Mismatch. Issue 22 (30th September 2019)

• Record Type: Journal Article
• Authors: Grijalva, Sandra I.; Gu, Jin‐mo; Li, Jun; Fernandez, Natasha; Fan, Jinqi; Sung, Jung Hoon; Lee, Seung Yup; Herndon, Conner; Buckley, Erin M.; Park, Sung‐Jin; Fenton, Flavio H.; Cho, Hee Cheol
• Is Part Of: Advanced science. Volume 6:Issue 22(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-09-30
• Subjects: biological pacemakers -- cell and tissue engineering -- sinoatrial nodes -- source–sink mismatch -- TBX18; Science -- Periodicals; 505
• DOI: 10.1002/advs.201901099
• Languages: English
• ISSNs: 2198-3844

Abstract

Abstract: Every heartbeat originates from a tiny tissue in the heart called the sinoatrial node (SAN). The SAN harbors only ≈10 000 cardiac pacemaker cells, initiating an electrical impulse that captures the entire heart, consisting of billions of cardiomyocytes for each cardiac contraction. How these rare cardiac pacemaker cells (the electrical source) can overcome the electrically hyperpolarizing and quiescent myocardium (the electrical sink) is incompletely understood. Due to the scarcity of native pacemaker cells, this concept of source–sink mismatch cannot be tested directly with live cardiac tissue constructs. By exploiting TBX18 induced pacemaker cells by somatic gene transfer, 3D cardiac pacemaker spheroids can be tissue‐engineered. The TBX18 induced pacemakers (sphTBX18) pace autonomously and drive the contraction of neighboring myocardium in vitro. TBX18 spheroids demonstrate the need for reduced electrical coupling and physical separation from the neighboring ventricular myocytes, successfully recapitulating a key design principle of the native SAN. β‐Adrenergic stimulation as well as electrical uncoupling significantly increase sphTBX18s' ability to pace‐and‐drive the neighboring myocardium. This model represents the first platform to test design principles of the SAN for mechanistic understanding and to better engineer biological pacemakers for therapeutic translation. Abstract : The engineering sinoatrial node (eSAN) in a dish design is inspired by the remarkable structure of the native SAN exit pathways. The architecture of the native SAN reduces the need for large number of pacemaker cells to spontaneously and autonomously pace‐and‐drive every single heartbeat.