Heart Disease: Fishing for a cure
Girisaran Gangnatharan, Institut de Génomique Fonctionnelle, Montpellier, France.
It is not just a little fish
“Why?” You ask me.
Because the tiny zebrafish may be the answer to the problem of heart disease in our society. Or, to be specific, this fish might be able to teach us how to repair your heart if you have a heart attack.
Before I explain how that is possible, we need to understand what happens during a heart attack.
Let’s take as our example Mr. Sam.
Mr. Sam is in his late 40s. He works in a bank and exercises twice a week to keep himself healthy. One fine day, Mr. Sam is working in his office and feels a small pain in his chest. He clutches his chest and falls to the floor.
Mr. Sam is having a massive heart attack.
As he lies on the floor, let’s jump into our hypothetical nano-submarine and zoom into his heart.
You witness first-hand the destruction as it unfolds: thousands upon thousands of his heart-muscle cells are dying almost instantly. These heart-muscle cells are required for the pumping action of his heart. Unfortunately, these heart-muscle cells cannot be replaced, and his heart is unable to pump blood efficiently to the rest of his body. Eventually, his heart will fail, and unless Mr. Sam has a heart transplant, he will die prematurely.
Would it surprise you if I told you that you could be the next Mr. Sam?
In fact, heart disease is so rampant, one out of every three people reading this article will most likely die of a heart attack.
Unless a creative solution to the problem of heart disease is found.
So what is the nature of the problem?
The problem is that Mr. Sam, you, and I cannot replace our heart-muscle cells if they are damaged. One promising solution, then, would be to find a way to stimulate our hearts to replace damaged cells.
This is where the zebrafish comes in.
“What on earth is a fish going to tell me about my own abilities to heal my heart?” You might ask.
If you cut off a small portion of this fish’s heart it will heal spontaneously. It will fully regenerate and replace the lost heart muscle.
Now some of you must be thinking, “well, this is great!” It is – if you are a zebrafish.
So the obvious question is: why can’t we heal our damaged hearts using the same mechanism that a zebrafish uses to heal its injured heart?
Why not?
Now I admit: you and I, we look nothing like fish. But did you know that zebrafish and humans share 70% of our genes? And, most importantly, did you know that the mechanism the zebrafish employs to heal its damaged heart also exists in mammals?
For example, if you were to remove a portion of the heart of a baby mouse, it would regenerate its heart in the same fashion as the zebrafish. However, as mice get older, they lose this ability to regenerate.
What this means is that the process by which a creature heals a damaged and injured heart is not specific to zebrafish; it is not specific to baby mice. It is not a genetic program specific to only a few animals. It is actually written in our own DNA.
But these genes were switched off in humans at some time during our evolution.
Our goal as scientists is to switch this genetic program back on. The zebrafish can tell us which human genes need to be turned on to repair the human heart.
Thanks to the zebrafish, cardiovascular disease could become a thing of the past in the coming decades: we would look at it the way we look at small pox today. Imagine a world where you would not have to go through the pain of losing a loved one to heart disease.
Who knows, this fish might actually save your life in the future.
It’s not just a fish…. It is hope!
About the Author:
Girisaran is a Final Year Graduate Student in Chris Jopling’s Lab at the Institut de Génomique Fonctionnelle, Montpellier, France. For his thesis, he has been studying the zebrafish. Unlike ours, if a zebrafish’s heart is damaged it will repair itself. If we could understand this process in the zebrafish, we could reverse engineer that into human therapies.