Bad Timing

Your heart isn't all muscle. Its muscle layer (myocardium) is sandwiched between endocardium and epicardium. Defects in the development of these layers can cause congenital heart disease (CHD), which affects one in 100 newborns. CHD can be caused by a coronary artery fistula (CAF) where a channel, partly comprising smooth muscle, develops between the coronary artery and another part of the heart. A defect in myocardium development may be to blame. Researchers investigated in chick embryos, damaging the myocardium before the epicardium layer forms. The result? Endocardium cells met epicardium cells too early, leading to CAF-like structures. The team then grew quail embryo myocardium (pictured, left) with chick embryo epicardial progenitors (right). Fluorescence microscopy revealed that where these different cells met, smooth muscle developed, and where they were apart, smooth muscle was absent. This supports the idea that CAFs form due to the inappropriately timed meeting of these cells.

Written by Lux Fatimathas

Lux Fatimathas

Writer

Having pursued science through a career in research, communications and publishing, she is currently a writer and editor for a healthcare marketing agency and also juggles freelance science writing.

• Image from work by P. Palmquist-Gomes and colleagues
• Department of Animal Biology, Faculty of Sciences, University of Málaga, Málaga, Spain
• Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in Experimental & Molecular Medicine, January 2023