Cell therapy for cystinosis.

In the September 2009 issue of Blood, Syres et al. [1] report on syngeneic bone marrow cell (BMC) and haematopoietic stem cell (HSC) therapy as a successful treatment in a mouse model of cystinosis, an autosomal recessive metabolic disease caused by a defect in the transport of cystine across the lysosomal membrane. The accumulation of cystine crystals in lysosomes leads to a multi-organ dysfunction including proximal tubulopathy and renal failure, corneal deposits, myopathy and central nervous system defects. By using Ctns knock-out (Ctns(-/-)) mice as a model for cystinosis, Syres et al. show that BMC transplantation leads to a major reduction of cystine content in all tissues tested, reflected by a significant attenuation of the development and progression of kidney injury and reduction in the number of mice with corneal cystine crystals. These changes were correlated with the engraftment of donor BMC producing a functional cystine transporter in the tissues tested. The transplantation of mouse HSC had the same therapeutic effect than whole BMC in this model, which is important as such HSC can readily be isolated from peripheral blood in humans. This work suggests that BMC or HSC transplantation is a potential treatment for cystinosis and other renal tubular disorders.