Harvard Medical School
At a glance:
- New study reveals that heart cells in zebrafish start beating suddenly and all at once to form a synchronized heartbeat.
- In developing zebrafish hearts, each cell can beat on its own, and unlike in an adult heart, the heartbeat isn’t coordinated by specialized pacemaker cells.
- Studying the basic biology of the heartbeat could help scientists understand cardiac rhythm disorders in humans.
Becoming a full-fledged organism out of a handful of cells, complete with functioning tissues and organs, is a messy yet highly synchronized process that requires cells to organize themselves in a precise manner and begin working together.
This process is especially dramatic in the heart, where static cells must start beating in perfect unison.
Now, a cross-school collaboration led by researchers at Harvard Medical School and Harvard University has provided a glimpse into exactly how cells in the heart start beating.
In a study conducted in zebrafish, the team discovered that heart cells start beating suddenly and all at once as calcium levels and electrical signals increase. Moreover, each heart cell has the ability to beat on its own, without a pacemaker, and the heartbeat can start in different places, the researchers discovered. The findings are published Sep. 27 in Nature .
“People place such importance on the heart beating that it’s been a focal point of investigations for a long time, but this is the first time we’ve been able to look at it in depth with so much resolution,” said co-senior author Sean Megason, professor of systems biology in the Blavatnik Institute at HMS.
Learning about the fundamental mechanisms underlying the heartbeat may be inherently interesting for the curious biologist, but it is also critical for understanding what is happening in situations where the cardiac system that regulates the heartbeat doesn’t develop properly, or begins to malfunction.
“The heart beats about 3 billion times in a typical human lifetime, and it must never take a break,” said co-senior author Adam Cohen, professor of chemistry and chemical biology and of physics at Harvard. “We wanted to see how this incredible machine first turns on.”