Seeking an End to the Bad Blood of Sickle Cell Anemia

2010-02-24 | |
Last updated: 2010-02-24
Sickle cell anemia blood cells

Our blood performs many, many tasks in the daily operation of our bodies. These tasks range from delivering nutrients to our cells and removing waste to transporting hormones to the right tissues. Of course delivery of oxygen and collection of carbon dioxide are also extremely important. Almost the entire volume of blood in our body is pumped once per minute or more. However, the flow of blood is not always easy, especially for people with blood disorders like Sickle Cell Anemia (SCA)

Sickle Cell Anemia is a disorder of the red blood cells or hemoglobin that occurs when these cells become dehydrated as a result of incorrect cellular chemistry. Like a deflated basketball or beach ball, the shape of the cells becomes something like a crescent. The deformed cells have a shortened lifetime of only 10 to 20 days instead of the approximate 120-day lifetime of healthy red blood cells. In addition, the disorder also causes the cells to tend to stick to one another.

The combined result of these abnormalities is that there are fewer red blood cells than normal and those that exist do not easily flow through the blood vessels nor do they transport oxygen very effectively. This leaves those suffering with the condition feeling chronically fatigued and short of breath. The poor flow of blood and low levels of oxygen can also lead to episodes of intense pain occurring at various locations within the body. The restricted blood flow may also result in organ damage, vision loss, strokes and high blood pressure.

The pain of Sickle Cell Anemia is frequent and according to a study from Virginia Commonwealth University, as many as 50% of SCA patients experience pain on most days. Almost 1 in 3 experience pain on a daily basis. The intensity of the pain often requires that morphine be provided to offer relief. Almost 90% of hospital admissions for the disease are because of the intense pain.

As the most common inherited blood disorder in the US, the condition affects about 72,000 people. In the UK, the number of people affected is more than 12,000. Sickle Cell Anemia is genetic in nature and primarily affects those of African, Mediterranean, Middle Eastern and Indian descent. Roughly 1 in 400 African Americans are affected by the condition.

Being a genetic disorder, a child has a 1 in 4 chance of developing the condition if both parents are carriers of the defective gene. One in 12 African Americans carries the gene.

Treatment of the condition typically involves use of the drug Hydroxyurea that causes an increase in the production of specific red blood cells. These cells are called fetal red blood cells because they are normally only produced when our bodies are developing in the womb. These cells have the benefit that they transport oxygen more effectively than normal blood cells and do not have the defect that causes the red blood cells to change shape. However, defective cells are still created and so the drug only improves the condition.

In the more severe cases, regular monthly to bimonthly blood transfusions are required to provide blood cells that can more effectively transfer oxygen to the body. Patients require such blood transfusions on an ongoing basis for the rest of their lives.

A more recent form of treatment that is typically used in only the most severe cases involves radiation treatment of a patient’s existing bone marrow to eliminate the ability of the bone marrow to create blood cells. Subsequently, radiation is followed by a bone marrow transplant from a donor. As with all transplants, there are risks of infection and rejection as well as a lifetime of anti-rejection drugs that limit the use of this option. The difficulty in finding donors also limits the use of transplants.

With no truly effective treatments for the condition, research efforts are in progress to understand and develop treatment. One such approach that attempts to increase the number of fetal red blood cells involves the use of the very popular resveratrol extract from red wine. The researchers from the Medical College of Georgia have found that the chemical is easier on patients than Hydroxyurea, a cancer drug. That said, deformed cells are still created and still pose a long-term risk.

An alternative to this approach that also relies on fetal red blood cells is being developed at Harvard Medical School. The approach involves gene therapy to permanently switch on the creation of fetal red blood cells within the genes of the patient. In mice, researchers found that after modifying the genes to create these blood cells, less than 10% of the cells being produced were of the defective type. If the research can be progressed to humans, this would almost cure the condition.

A different approach that also offers great promise is one being developed at Yale University where scientists are using a new form of gene therapy to treat the condition. The efforts in this case involve altering the genes within the cells of the bone marrow that are responsible for creating red blood cells. By making the changes to these blood-creating cells, the theory is that all future blood cells should be free of the condition and should operate normally. Further efforts will determine if Sickle Cell Anemia can be effectively cured in this manner.

If you have experience with Sickle Cell Anemia, feel free to share your experiences in the discussion forums.

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