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Stem cells

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Using stem cells: the cardiovascular system

Stem cellstem cell
Cells which can divide repeatedly without becoming differentiated and have the capacity to develop into a diverse range of specialised cell types.
research is an exciting new area in biotechnologybiotechnology
The use of biological organisms or enzymes to create, break down or transform a material.
. Although it has not yet produced a mainstream cure for people, there are some very effective treatments in place for horses, and human trials are progressing fast. This research is still very young: embryonic stem cellsembryonic stem cells
Embryonic stem cells (ESCs) are undifferentiated, pluripotent cells derived from the inner mass of an early embryo at the blastocyst stage.
were only first cultured in 1998, and iPSCiPSC
These are induced pluripotent stem cells which are produced from differentiated adult cells.
s first created in 2006. Therefore, the clinical trials using stem cells already underway are mainly testing their safety rather than their capabilities. Fortunately, stem cells don’t need to be transplanttransplant
The process of replacing a damaged or diseased organ with a healthy organ from a dead or living donor.
ed into someone to act as a treatment: research in the lab using stem cells as disease models offers a way of testing new drugs and carries fewer risks than human stem cell trials.

Experimental evidence that stem cell therapy does work continues to grow. Here you are going to look at progress using stem cell therapies in a number of different areas of human health, starting with the cardiovascular system.

Heart attackheart attack
The result of a lack of blood to the heart muscle due to atherosclerosis in the coronary arteries. It can be fatal.
s

Cardiac progenitor cells are tissue stem cellstem cell
Cells which can divide repeatedly without becoming differentiated and have the capacity to develop into a diverse range of specialised cell types.
s found in the heart which can differentiate to form cardiomyocytes. During a heart attack, areas of heart muscle are damaged and can’t repair themselves, which may lead to heart failureheart failure
When the heart fails to pump blood effectively round the body as a result of the weakening or stiffening of the cardiac muscle or as a result of damaged heart valves.
.

Unfortunately, the body’s ability to produce new cardiomyocytes decreases with age, as the likelihood of a heart attack increases – and so the mammalian heart shows little potential to regenerate without medical help. It is already known that zebrafish can repair damage to their hearts following a heart attack – it is thought that by introducing stem cells into the damaged area or stimulating local cardiac progenitor cells mammals could also be able to repair heart damage.

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This is not something that is routinely performed on humans, but trials in other mammals have shown promising results: mouse stem cellstem cell
Cells which can divide repeatedly without becoming differentiated and have the capacity to develop into a diverse range of specialised cell types.
s can repair damaged areas of mouse hearts when introduced after a heart attackheart attack
The result of a lack of blood to the heart muscle due to atherosclerosis in the coronary arteries. It can be fatal.
, whilst human stem cells show the same effect when introduced into damaged rat hearts following a heart attack. Trials are currently underway to investigate whether adult stem cells can help hearts recover from both heart failureheart failure
When the heart fails to pump blood effectively round the body as a result of the weakening or stiffening of the cardiac muscle or as a result of damaged heart valves.
and from heart attacks. Some very positive results are emerging. For example, in one small scale study published in 2016 in the Journal of Cardiovascular Translational Research, 11 patients having bypass surgerybypass surgery
Surgery which bypasses coronary arteries affected by atherosclerosis with healthy blood vessels taken from other areas of the body.
also had stem cells injected into their heart muscle where there was scar tissue from previous heart attacks. All of the patients were at very high risk of dying at the time of the procedure, but 24 months later they were all still alive and there was a 40% reduction in scarring, a 30% improvement in heart function and a 70% improvement in quality of life. Of course the patients had heart bypass surgery which would improve their condition too, but the reduction of scar tissue and increase in function excited scientists. A large-scale controlled study of this technique was done in London in 2017.

Long QT syndromelong QT syndrome
A genetic problem in the heart which can lead to the sudden death of apparently fit young people.

Although one of the major goals of stem cellstem cell
Cells which can divide repeatedly without becoming differentiated and have the capacity to develop into a diverse range of specialised cell types.
technology for the future is to develop therapies which can be used to repair damage caused by a disease or injury, it already plays a major role in investigating diseases. Animal models have a limited value because there are differences between the hearts of all species of mammals. For example, long QT syndrome is a rare genetic disease that can lead to the sudden death of young people. It takes the heart muscle longer to recover after each beat, and it can result in arrhythmiaarrhythmia
An irregular rhythm of the heart.
s which can be fatal.

iPSCiPSC
These are induced pluripotent stem cells which are produced from differentiated adult cells.
and ESC technology offer scientists the opportunity to model the disease: iPSCs and ESCs from patients suffering from long QT syndromelong QT syndrome
A genetic problem in the heart which can lead to the sudden death of apparently fit young people.
 have been differentiated to form cardiomyocytes which contain the mutant DNA that causes the disease. There are a number of different mutationmutation
A change in the arrangement or amount of genetic material in a cell.
s which all result in similar disease, but which respond differently to potential treatments. Stem cellstem cell
Cells which can divide repeatedly without becoming differentiated and have the capacity to develop into a diverse range of specialised cell types.
s derived from affected patients have been grown, differentiated to give cardiomyocytes and then used in conjunction with normal cardiomyocytes to study the mechanisms of the disease at the molecular level, to identify mutations for potential 
gene therapygene therapy
A new, experimental method of fighting disease by replacing a defective gene with a healthy gene.
 and to test possible treatments.

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