Replacing the blood to help the brain

KM Transplantat by John Bergenholtz on Wikimedia Commons. Used under Creative Commons license.

Blood-forming stem cells, ready for transplanting. (John Bergenholtz/Wikimedia Commons)

Hematopoietic stem cell transplants, or HSCTs — which is what they’re calling bone marrow transplants these days * — are no longer just last ditch treatments for aggressive blood cancers. Doctors are using them for an ever-wider range of conditions, including some solid tumor cancers (like neuroblastomas) and disease of the blood that aren’t cancer (think certain anemias or sickle cell disease).

Over at Boston Children’s Hospital’s Vector, I wrote a couple of days ago about how doctors are also starting to give HSCTs to children with a select few metabolic disorders — conditions like adrenoleukodystrophy (ALD) where their cells can’t produce important enzymes. As such, the cells can’t carry out important chemical reactions that would keep them healthy. The upshot in many of these conditions is that the brain starts to malfunction.

As I note:

Why would transplanting stem cells be of use here? ALD provides a good example. Children with the condition cannot produce an enzyme called ALDP, which helps break down fatty acids in the brain and the rest of the body.

The cells that normally produce ALDP are derived from hematopoietic stem cells, so receiving healthy stem cells from a bone marrow donor enables patients with ALD to begin producing the missing enzyme. Some of the new stem cells travel to the brain and differentiate into microglial cells, which can supply the enzyme to the brain and spinal cord.

Here’s the kicker, though: the transplant won’t reverse the disease, just slow or stop it. Whatever damage that has been done will remain. And you have to do it while the child is young; if they’ve progressed too far, the transplant won’t save them.

Head over to Vector to read the rest.

While you’re there, check out some of the other stuff I’ve posted recently about things like taking a Lego-like approach to designing new vaccines, or how obesity may be on the rise even among children with sickle cell disease, children who historically have been skinny sometimes to the point of malnourished.

* And HSCTs have moved beyond just bone marrow, too. Doctors can also use umbilical cord blood from newborn babies — which is rich in blood-forming stem cells —  and even blood drawn from the circulation to carry out an HSCT.


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