In coronary heart disease (CHD), plaques or fatty substances build up inside the walls of the arteries. The plaques also attract blood components, which stick to the artery wall lining. Called atherosclerosis, This process, called atherosclerosis, develops gradually over many years. When too little blood reaches the heart, the condition is called ischemia. Chest pain, or angina, may occur. If a blood clot suddenly cuts off most or all blood supply to the heart, a heart attack results. Cells in the heart muscle that do not receive enough oxygen-carrying blood begin to die. The more time that passes without treatment to restore blood flow, the greater the damage to the heart.

Treatments for a heart attack work to open the blocked artery to restore blood flow as fast as possible to prevent or limit damage to the heart muscle, and to lessen the chance of a repeat attack. The main treatments are "clot-busting" medications, thrombolytic therapy, and special procedures, such as insertion of a stent during angioplasty or coronary artery bypass surgery. A new stem cell therapy is tested, as shown in the film "Beat of the Heart", to try and restore blood vessel growth in the heart muscle by the use of a fraction of the patients own bone marrow cells.

The aim of a cell therapy is to repair diseased or injured body parts with healthy new cells. These could be (derived from) stem cells that are able to differentiate into the targeted cell type and tissue. Bone marrow transplantation is a kind of stem cell therapy, which is already widely applied to treat leukaemia and other blood disorders. Bone marrow stem cells from a donor are injected into the patient's blood and form healthy blood cells. Rejection of the foreign donor cells by the immune system still poses a problem.
To avoid rejection, scientists want to use the patient's own stem cells to regenerate tissues. This is still in an experimental phase, but is seen as promising with great potential. The hope is to treat a wide range of human disorders, such as neurological diseases (e.g. Parkinson's disease), spinal cord injuries, skin burns, diabetes or cancer.

Stem cells are very special body cells. Serving as a sort of repair system, they have the potential to develop into many different cell types in the body. Theoretically they can divide without limits to renew themselves, or divide and differentiate into other, specialised cells such as a muscle cell, a red blood cell or a brain cell. Stem cells have the ability to form different types of tissues and organs, and they are present in every adult as well as in embryos.
Embryonic stem cells, as their name suggests, are present in embryos. They can develop in (almost) all body cells (see "Read more"). For research purposes, embryonic stem cells are derived from embryos that develop from eggs that have been fertilized in vitro - in an in vitro fertilization clinic - and then donated for research purposes with informed consent of the donors. However, some countries have strong legal restrictions on research with human embryonic stem cells.
An adult stem cell is an undifferentiated cell found among differentiated cells in a tissue or organ, can renew itself, and can differentiate to yield the major specialized cell types of the tissue or organ. The primary roles of adult stem cells in a living organism are to maintain and repair the tissue in which they are found. Some scientists now use the term somatic stem cell instead of adult stem cell.
Stem cells are very interesting for medical situations, in which tissues have to be regenerated (e.g. burns, multiple sclerosis, Parkinson's disease).
In addition, the specific factors and conditions that allow stem cells to remain unspecialized are of great interest to scientists. It has taken scientists many years of trial and error to learn to grow stem cells in the laboratory without them spontaneously differentiating into specific cell types. For example, it took 20 years to learn how to grow human embryonic stem cells in the laboratory following the development of conditions for growing mouse stem cells. Therefore, an important area of research is understanding the signals in a mature organism that cause a stem cell population to proliferate and remain unspecialized until the cells are needed for repair of a specific tissue. Such information is critical for scientists to be able to grow large numbers of unspecialized stem cells in the laboratory for further experimentation.

More knowledge on the genome, can lead to the cause of a disease - malfunctioning of a protein and hence a mutant gene - more easily. In addition, knowing this gene will allow screening for the disease. Genetic diagnosis will allow assessing the individual genetic predisposition. The understanding of how genes influence whether and how a medication works and whether it causes side effects could lead to personalized drug treatment. To achieve this, genetic tests would have to become a part of standard diagnosis.
Knowing more about the molecular causes of a disease not only accelerates progress of research towards diagnosis, but also towards prevention and therapy of the disease. Since diseases have very rarely a single cause, the way is not straightforward. Nevertheless, the efficacy of the new treatments of diseases such as cancer, Alzheimer or cystic fibrosis is improving steadily.
Knowledge about bacterial and viral genomes helps to identify more easily the mechanisms of infections and thus improve their prevention and treatment. The benefits of this technique joined to efficient international collaborations were illustrated during the outbreak of SARS in 2003; the genome was deciphered within a week after the pathogenic agent had been identified. Already a few months later, promising vaccines are under development.