Tranylcypromine,
or TCP, was found to able to trick the precursors of red blood cells into
making a different form or hemoglobin, usually only found at the fetal stage,
offering hope to people suffering from the disease.
"Sickle
Cell Disease is characterized by a modification in the shape of the red
blood cell from a smooth, donut-shape into a crescent or half moon shape. The
misshapen cells lack plasticity and can block small blood vessels, impairing
blood flow. This condition leads to shortened red blood cell survival, and
subsequent anaemia, often called sickle-cell anaemia. Poor blood oxygen levels
and blood vessel blockages in people with sickle-cell disease can lead to
chronic acute pain syndromes, severe bacterial infections, and necrosis (tissue
death)."
Sickle
Cell Disease is caused by a mutation in a certain gene for hemoglobin, the
protein that is abundant in red blood cells that carries oxygen throughout
one's body. People with one copy of the mutated gene have no health
effects, while those with both copies of the mutated gene have lie long health
issues.
The
study, published in Nature Genetics, tested the drug on human and mouse cells
outside of the body and found that the drug stops a mechanism in place that
blocks production of fetal hemoglobin, the protein LSD1. When this block is
taken out, the cells start producing normal fetal hemoglobin proteins and not
the defective adult hemoglobin genes (there is a switch of which gene is used
during the transition from a baby residing in the uterus and surviving
breathing air outside the womb).
"This
is the first time that fetal hemoglobin synthesis was re-activated both in
human blood cells and in mice to such a high level using a drug, and it
demonstrates that once you understand the basic biological mechanism underlying
a disease, you can develop drugs to treat it," says Doug Engel, Ph.D., senior author
of the study. "This grew out of an effort to discover the
details of how hemoglobin is made during development, not with an immediate
focus on curing sickle cell anemia, but just toward understanding it."
Current
treatment tries to boost fetal hemoglobin production using hydroxyurea, and
other forms of treatment such as blood transfusions and bone marrow transplants
are expensive and risky.
Because
the drug was used in the past, it has already been approved by the government
and is no longer under patent, so it would be cheap to distribute.
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