I took part in the Nottingham summer school, which was a great week to know a bit more about medicine. I have been interested in heart mechanisms so when a talk about “mending broken hearts” was introduced, I went on to researching a bit about this. I found that a fish species known as zebrafish (native to South Asia ) are a significant model in the regenerative biology of hearts and in particular the fixing of “broken hearts”. I know, quite intriguing right?
The zebrafish has characteristics, which makes it a “smart model” for the study of hearts. Zebrafish can repair its damaged heart in a matter of weeks whereas in humans this is very unlikely. The most intriguing characteristic, which is probably also the most important, is that the zebrafish is transparent in its early life cycle. Therefore, researchers are able to see the blood vessels and heart itself grow, which would be fascinating to see I’m sure. Due to their heart being able to develop just 12 hours after birth, the researchers are provided with quick results, making it advantageous for their research. The heart starts out as one long tube and then twists and folds to become the shape we recognise. A consultant cardiologist suggested that switching of particular genes in the zebrafish to identify how blood vessels regrow and repair, will help to identify the genes responsible for the mending of the broken heart. Using the same idea, the possibility of switching the right genes in humans would mean a higher chance of surviving a heart attack ,for example. Zebrafish allow a wide range of genetic manipulation and provided that there are fewer ethical restrictions to mammalian models, they are increasingly being used for research in biology.
To fully regenerate the heart, the zebrafish leaves a temporary scar due to new cardiac muscle cells being formed. Despite having anatomical differences between humans and fish species, the aspect of being vertebrates and having similar cellular structure allow information to be extrapolated by scientists. Zebrafish embryos that lacked blood circulation, are still supplied with oxygen as they reach all tissues due to passive diffusion as the embryo is so small. This is where for humans this is completely different as the narrowing of arteries due to fatty deposits leads to insufficient blood being supplied. Heart attacks are normally treated with intervention and catheterised procedures, which involves balloon angioplasty and inserting stents to keep narrow arteries open.
Therefore, the introduction of the zebrafish into the development of research to improve “broken hearts” is fascinating. The burden of cardiovascular diseases is staggering and so the developing research into these fish species may be extremely beneficial for future cardiologists!