Pluripotent stem cells can make virtually every cell type in the body. But until now, one type has remained elusive: blood stem cells, the source of our entire complement of blood cells.
Since human embryonic stem cells (ES cells) were isolated in 1998, scientists have tried to get them to make blood stem cells. In 2007, the first induced pluripotent stem (iPS) cells were made from human skin cells, and have since been used to generate multiple cell types, such as neurons and heart cells.
But no one has been able to make blood stem cells. A few have have been isolated, but they’re rare and can’t be made in enough numbers to be useful.
Translational neuroscience research has seen a disappointing streak of failed clinical drug trials. While the need for therapeutics that target the nervous system is growing, recent results in diseases like Alzheimer’s and autism have disappointed, and many companies have begun to downsize their R&D investments. Prospects are glum for patients who need new therapies to help manage their disorders.
The frustration is that drug candidates that have shown promise in animal models have not demonstrated efficacy in humans. Mouse models are not proving to be sufficient surrogates for human neurologic disease. Human brains and brain cells are built and function differently, and many neurodevelopmental disorders—hard enough to diagnose in human children—don’t have identifiable behavioral counterparts in mice. As I hear over and over from scientists, there is no such thing as a mouse with autism.
But for a handful of children, it’s the source of one of the most devastating brain infections known—herpes simplex encephalitis (HSE)—causing fever, confusion, personality changes and seizures. If not caught and treated with high-dose antivirals, it’s highly fatal, and even with treatment most children are left with irreversible brain damage.
Why do some children develop HSE while everyone else just shrugs the virus off? …