Studying fish hearts could yield clues to treating or preventing heart damage in humans.
Research scientists at the University of Guelph (Ontario, Canada) have examined how fish change the size of their heart based on the temperature of the water, resulting in a larger and stronger heart in colder temperatures so the fish can remain active throughout the year.
Rainbow trout, salmon and other species put on collagen in the winter and take it off in the summer so they can keep swimming over a broad range of temperatures. Collagen is a structural protein found in connective tissues; it is the “glue” that helps hold the body together. Rainbow trout are able to produce more collagen and increase their heart size by as much as 50% their normal size in colder temperatures. The ability for some fish to remodel their heart enables them to remain active over a wide range of environmental temperatures.
It is imperative to study fish’s addition and removal of collagen further, as fish hearts and human hearts are similar in composition. When human hearts are injured from a heart attack or other stressor the body responds by building a scar composed of collagen in the damaged area. This scar has lasting damage and impairs cardiac function through the remainder of the human’s life. If we understand how fish are able to regulate and remove collagen from the heart in warmer months then we may be able to develop a more controlled way for the human heart to repair itself after a heart attack.
Click here to access a summary of their findings.
Johnston, E.F. and T.E. Gillis. 2017. Transforming growth factor beta-1 (TGF-β1) stimulates collagen synthesis in cultured rainbow trout cardiac fibroblasts. The Journal of Experimental Biology, 220:2645-2653. DOI:10.1242/jeb.160093.