A new study has helped unravel the mystery explaining how zebrafish regenerate a broken heart. Their findings, published in Nature Genetics, reveal how these amazing little fish can regrow up to 20% of their heart in only 2 months following an injury. This regeneration is driven by signals released from special cells called fibroblasts.
When the heart of zebrafish is injured by a stimulus that mimics a heart attack (using a very cold needle under anesthesia), the initial inflammation response is very similar to that of humans. Unlike humans, however, the fish begin to grow new heart muscle cells (cardiomyocytes) and blood vessels to supply the new tissue with oxygen and nutrients. Whereas in humans, the damaged area develops permanent scar tissue that weakens the heart.
By analyzing heart cells before and after injury, the research team discovered three kinds of fibroblasts that were stimulated and promoted the growth of new tissue by activating the production of collagen XII.
These are exciting findings because the identification of how other species successfully regenerate heart tissue may one day lead to new therapeutics to treat heart attacks.
B Hu, S Lelek, B Spanjaard, H El-Sammak, MG Simoes, J Mintcheva, H Aliee, R Schafer. AM Meyer, F Theis, DYR Stainier, D Panakova, JP Junker. Origin and Function of activated fibroblast states during zebrafish heart regeneration. Nature Genetics. 2022. https://doi.org/10.1038/s41588-022-01129-5