Friday, 21 June 2013

How can you mend a broken heart?

New research has suggested that the zebra fish, which is capable of repairing its own damaged heart, may hold the answer the curing the problem of cardiovascular disease. 

Heart attacks occur when there is a disruption in the supply of blood to the heart, leading to the cells of the heart to be damaged and die. This occurs most commonly because of a blockage in one of the arteries that supplies blood to the heart, which can occur in a number of different ways. This blockage prevents the cells of the heart from receiving the oxygen they need, leading to their death.

Cardiovascular disease, (especially heart attacks) remain one of the leading causes of death in the world. This is because the adult mammalian brain isn’t capable of sufficiently repairing the heart tissue that is damaged, and instead replaces the damaged tissue with a fibrous collagen scar. Because of this, there is a huge amount of research being geared towards identifying new therapies and strategies to induce the regeneration of lost heart tissue.

Yet again, science has turned to other animals which are capable of things we are not to answer their problems. Studies in the past have shown that fish and amphibians are capable of regenerating their broken hearts, with particular interest in the zebra fish. Zebra fish are particularly useful as a scientific tool because of their simplicity and the high economy with which they can be investigated. So far, using zebra fish has allowed us to conduct genetic suppressor and enhancer screens to identify how the risks of heart disease can be inherited, as well as giving us a massive amount of information on the discovery of new drugs that can be used during therapy.

One piece of research has been able to produce a heart model in the zebra fish using cryoinjury, in order to establish how the zebra fish is capable of repairing itself. Cryoinjury produces a brutal attack on the heart, with 20% cell death of the ventricular wall. From these experiments it could be observed that the initial stages of response are very similar between the zebra fish and us humans. However, later stages of response differed dramatically. As mentioned earlier, in humans the heart tissue is replaced by a fibrous scar tissue. This also occurs in zebra fish but with this scar tissue being progressively replaced by new heart tissue, removing the scar and returning the heart to normal. It was also shown during this research that this tissue remodelling is associated with the accumulation of cimentin-positive fibroblasts and the expression of an extracellular matrix protein Tenascin-C. Further understanding the zebra fishes mode of repair could be crucial in developing therapies for humans, which may allow us to mimic their method of regeneration.

If this type of research continues along the same path and the same rate as it is, we may not be too far away from being able to produce an effective treatment against heart disease. If that does turn out to be the case, we'll owe a lot to the humble zebra fish. 

What do you think about this type of research? Write below with comments and questions or email newsinscience@gmail.com. 

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