Heart cell transplantation and adult stem cell therapy

Heart cell transplantation

This dilemma — what to do for patients with severe heart failure who are unable to receive heart transplants — stimulated researcher's interest in heart cell transplantation, an exciting new field with the potential to improve the quality of life and lengthen the lives of patients who suffer from heart failure.

At the time of their heart catheterization, patients with poor heart function would have a very small amount of heart muscle tissue removed. This tissue would be grown in the laboratory over several weeks to obtain a much greater number of cells. Then, during heart surgery, the cultured heart cells would be transplanted back into the patient’s heart. The resulting improved heart function will hopefully result in a greater exercise capacity, better quality of life, and longer life expectancy.

This form of therapy does not apply only to heart muscle cells but also to the cells that form blood vessels. When blood vessel cells were transplanted into the scar tissue, it is found that the number of blood vessels in the area tripled. A combination of heart muscle cells, to improve heart function, and blood vessel cells, to improve blood flow to the heart, might be the best solution for failing hearts with inadequate blood flow. This is exactly the situation seen in many patients with advanced atherosclerosis.

Heart cell transplantation is an exciting new technology with the potential to improve heart function and blood flow in patients with advanced heart failure and extensive atherosclerosis. It may also lead to the development of living graft materials that can be used to repair heart defects in children, avoiding the need for second or third operations.

Adult Stem cell therapy for heart patients

The concept of myocardial cellular therapy was originally conceived based on the example set by the success of whole organ transplantation—replace what has been lost. However, with the need for whole organ transplantation far exceeding the organs available for donation, the goal of cell-based therapy is to restore cardiac function by the replacement of only the sections of dead myocardium. Here the replacement of lost heart cells (myocytes) would be accomplished by the implantation of a population of readily available cells that integrate into the existing matrix and provide synchronized contractile activity.

Adult Stem cell therapy is a new treatment modality for patients with coronary artery disease aiming at improving symptoms especially if other treatment modalities such as PTCA  and bypass surgery  fail. Stem cells are also been used for treating patients with heart failure in an attempt to improve heart function. So Let us give a hint on stem cells.

Stem cells are certain body cells which have the ability to grow and change into different body cells. These cells are responsible for repairing damaged tissues of different organs of the body and they can work and divide as long as you are alive. When these cells multiply, the can remain the same cells or surprisingly can change to another cell such as brain cell, heart muscle cell or even a blood cell. One of the most important properties of stem cells is their ability, under certain conditions, to change into cells with specific functions such as beta cells of the pancreas which produce insulin or even cardiac muscle cells which infinitely contract and beat. While you are still in the womb of your mother, these cells were present in your very small developing tissues. Stem cells at that time start to multiply and develop into different body organs as the heart, liver, pancreas and nervous system.

Stem cells live in certain areas of each organ where they may remain lazy. The only factor that makes them active is the development of an injury or disease in the tissues they live within.

Let us a compare a stem cell to a heart muscle cell. The stem cell cannot do any special function. For example a group of stem cells cannot form together a muscle tissue that can contract and pumps blood as a group of heart muscle cells can do. However, stem cells can divide and multiply and then differentiate into a different type of cell as a heart muscle cell. On the contrary, the heart muscle cell will perform the function but it cannot renew itself by multiplying.

Adult stem cells usually give rise and differentiate into cells that they originally live in between them. An adult stem cell in the bone marrow will give rise to white blood cells, red blood cells and platelets. However, a number of experiments over the last several years have raised the possibility that stem cells from one tissue may be able to give rise to cell types of a completely different tissue. This can be observed in blood cells becoming nerve cells, liver cells that can differentiate into pancreatic cells that produce insulin, and bone marrow stem cells that can become heart muscle.

Adult stem cell on exposure to specific signals in the Lab., have shown the ability of generating myocytes (heart muscle cells). What is also surprising is that stem cell transplantation, in itself, is a sufficient stimulus for them to change to a different cell. Researchers proved that the desired native tissue (diseased heart tissue in this case) offers the stem cell an environment rich in the signals of differentiation.

How are the stem cells transplanted?

As we already mentioned that your bone marrow has adult stem cells that can differentiate into heart muscle cells (myocytes). The procedure begins by withdrawing a sample from your bone marrow usually from a big bone such as the pelvic (hip) bone. These cells are treated and activated in the lab before administration into your body. The next step after activating your stem cells is their delivery to your heart. The procedure of delivery is quite similar to a coronary angiogram. The stem cells are injected using a catheter introduced into your groin and moving it until it reaches your coronary arteries. Another way is during your routine heart bypass surgery or valve surgery. The stem cells are injected with a needle directly into the diseased heart muscle.

Stem cell therapy offers the physicians a new weapon in the battle for prevention and treatment of heart diseases. Numerous studies demonstrate that stem cell therapy is safe and effective treatment option to treat both sudden and long term heart diseases with the ultimate goal of prevention of end stage heart failure. Several questions remain to be evaluated, including identification of the ideal cell type, the exact cell dose, timing and number of treatments.