When I was growing up, an old man used to visit his nephew, a policeman who lived next door to us. The old gentleman was quiet and shy, and would nod but not talk to us kids.

His nephew explained that the old gentleman had no family; his son died at age 38 of sickle cell disease, and because the son’s problem was genetic, he and his wife had no furthur children, nor did his son. So he loved to visit his remaining family, including his nephew, whose children were healthy…but the visits made him sad, seeing what might have been, but was not….

Sickle cell disease
is a nasty disease. Ironically, most of my work in Africa was with tribes living in the highlands, so we had few cases. I diagnosed one case in three years: and that mom was from outside our area: migrants to work at a nearby asbestos mine. That is because, although sickle cell disease is probably fatal in countries without modern medical care, the sickle cell trait (where some but not all of one’s blood cells are prone to sickle) is thought to give resistance to fatal cases of malaria. Since there was little malaria in the highlands, those tribes tended not to have the trait, but tribes from nearby lowlands did.

In Sickle cell, the molecule of the hemoglobin, the molecule that carries oxygen, is abnormal…usually it’s okay, but if the oxygen level falls too low, it starts a domino effect and crystalizes into a long hard thread…and the nice, platelike red blood cells become shaped like a sickle or crescent moon, and get stuck in smaller blood vessels, causing blood clots.

When sickle-shaped cells block small blood vessels, less blood can reach that part of the body. Tissue that does not receive a normal blood flow eventually becomes damaged. This is what causes the complications of sickle cell disease. There is currently no universal cure for sickle cell disease.

A lot of these people have chronic pain, and end up either addicted to narcotics, or being accused of addiction because they come so often to the emergency room for pain medicine. The sickle cells often destroy the spleen (whose function includes “weeding out” old red blood cells) but the spleen also helps produce immunity to certain bacteria, such as pneumococcus. The increase in life span is mainly from stopping pneumococcal sepsis, by giving penicillin to prevent infections, and by using various vaccines.

Treatment includes oxygen, hydration (giving fluid), pain medicine, and hydroxyurea, a medicine that helps keep the blood from sickling. The main treatment is to prevent infections.

For awhile, there was a debate about giving transfusions to keep people from getting anemic, since anemia makes people’s oxygen level go low, and then you are more prone to cause the clots: but I haven’t heard of it being done in the last ten years.

Experimental treatment to cure the disease includes bone marrow transplant, with the problem of finding a matching donor. Since immunizations and antibiotics and aggressive treatment of “crisis” episodes make the life span almost normal, few are willing to do a risky bone marrow transplant that could end up making the patient’s life shorter. And there are screening tests to check for “sickle cell trait”.

The irony? Nearly all people with sickle cell disease are African American, but if you only screen African Americans, you are discriminating…but if you screen everyone, you are wasting money. And to make things worse, if you are African American with the mostly harmless “trait”, and you say you have the trait, it would open you to discrimination in jobs and in getting health insurance.

But in today’s paper we are hearing that doctors might be able to use skin cells to produce bone marrow that can produce normal blood cells.

Researchers from the University of Alabama at Birmingham and Massachusetts Institute of Technology are reporting significant progress in the fight against sickle cell disease, according to a paper published today in the journal Science.

Using a recent breakthrough discovery in which scientists learned how to create stem cells from skin cells, researchers have corrected the genetic fault that causes sickle cell disease in laboratory animals.

Originally, the scientists were going to use embryonic stem cells, but were facing a lot of technical problems:

Townes figured that embryonic stem cells might help the 95% of patients who couldn’t find donors. But the process would be complicated.
First, scientists would have to clone embryos using the patient’s own DNA. Then they would switch (the errors in the DNA)…Stem cells would then have to be harvested from the modified embryo and used to make healthy bone marrow for a transplant…

But in the meanwhile, the new way of getting embryo like cells (iPS cells) from skin appeared, and they decided to try that instead:

They got skin cells, changed the cells back to embryo like cells, then snipped out the bad segment of DNA and replaced it with correct DNA. Then they used another virus to make the stem cells grow up into bone marrow cells. Finally they put the bone marrow cells back into the mice…and it worked…so far…

This is the photo from their web page:
The whole point is that once the key to making cheap and abundent stem cells was achieved (and remember, it was only announced last week) then everyone can get into the act.

It will be several years before we know if this type of treatment will work, and there will be worries about the stem cells turning cancerous, but if it pans out, in about ten years we might have a cure for sickle cell disease and other blood diseases such as thalessemia.


Nancy Reyes is a retired physician living in the rural Philippines. Her website is Finest Kind Clinic and Fishmarket and she writes medical essays at HeyDoc Xanga Blog

Be Sociable, Share!