The only available drug to treat cystinosis, cysteamine, while slowing the progression of kidney degradation, does not prevent it, and end-stage kidney failure is inevitable.
"Cysteamine must be given every six hours, so children have to be woken up each night to take this drug, which has unpleasant side effects, and many others to treat various symptoms," Cherqui says. "So although there is treatment, it is difficult treatment that does not cure the disease."
"Surprised and Encouraged"
In the new study, the researchers found that transplanted bone marrow stem cells carrying the normal lysosomal cystine transporter gene abundantly engrafted into every tissue of the experimental mice. This led to an average drop in cystine levels of about 80 percent in every organ. In addition to preventing kidney dysfunction, there was less deposition of cystine crystals in the cornea, less bone demineralization, and an improvement in motor function.
"The results really surprised and encouraged us," says Cherqui, who as a doctoral student in France in 1998 helped discover the gene involved in cystinosis. "Because the defect is present in every cell of the body, we did not expect a bone marrow stem cell transplant to be so widespread and effective."
Cherqui, who generated the mouse model in 2000 that is currently used to study cystinosis, says that adult bone marrow stem cell therapy is particularly well suited as a potential treatment for cystinosis because these cells target all types of tissues. In addition, stem cells reside in the bone marrow for the duration of a patient's life, becoming active as needed, a particular benefit for a progressive disease like cystinosis.
The work of Cherqui and her colleague
|Contact: Keith McKeown|
Scripps Research Institute