A study published in Science indicated that the amino acid valine, which can be obtained by eating protein, may be important for the formation of blood stem cells, and has potential therapeutic implications in patients with hematologic cancers.
In the study, which was conducted by researchers at the Center for Stem Cell Biology and Regenerative Medicine at The Institute of Medical Science at the University of Tokyo in Japan, mice were deprived of valine for two to four weeks. These mice appeared to stop making new blood cells altogether. “In mice fed a valine-restricted diet, HSC frequency fell dramatically within one week,” the authors reported. “Furthermore, dietary valine restriction emptied the mouse bone marrow niche and [allowed] donor-HSC engraftment without chemoirradiative myeloablation.”
Laboratory tests also showed that human blood stem cells appeared to be dependent on valine. The authors hypothesized that if this proves true, depriving patients of valine prior to bone marrow transplant could be an alternative to or reduce the need for chemotherapy and radiation. In addition, the lack of valine could even kill off the cancer-causing cells in the patients’ blood.
Incorporation into clinical use will not be straightforward, though, as some of the mice died from a lack of the nutrient, which is also involved in metabolism and tissue repair. The researchers also found that human blood stem cells failed to proliferate when cultured without valine.
Sources: Taya Y, Ota Y, Wilkinson AC, et al. Depleting dietary valine permits nonmyeloablative mouse hematopoietic stem cell transplantation. Science. 2016 October 20. [Epub ahead of print]; Scientific American, October 20, 2016.