An editorial in the June 11th edition of Nature does two things remarkably well: it offers hope for the future of stem cell science while explaining why it takes so long to get things right.
Headlined “Good practice” the Nature piece explains why: “… shortcuts are simply not possible, despite charlatan claims. It takes time to learn how to coax stem cells — either from human embryos or from reprogrammed adult cells known as induced pluripotent stem (iPS) cells — to develop into the right sort of replacement cell. It also takes time to work out how to get these cells to integrate into the host tissue and to function. And the steps required to work out how many replacement cells need to be delivered, and how to deliver them safely, cannot be rushed …”
The editorial urges patience as the field “inches towards clinical testing” and points to two recent developments that inspire considerable optimism.
One is the commencement of clinical trials to treat macular degeneration using retinal stem cells (covered in previous posts here).
The other is the resumption of a clinical trial to test whether embryonic stem cells can help regrow nerves damaged by spinal cord injury. The original trial was halted in 2011 when Geron, the company behind it, decided to use its limited resources elsewhere. Now Asterias Biotherapeutics, buoyed by a $14.3-million grant from the California Institute for Regenerative Medicine, is picking up where Geron left off. (Nature doesn’t mention a Canadian led spinal cord study, but you can read about it here.)
As the article points out, the eye and the spine, in terms of stem cell research, present somewhat easier paths to the clinic: both are isolated, closed systems. The brain and heart, however, are far more complicated. Developing new, stem cell-derived treatments for diseases like Alzheimer’s and Parkinson’s and for cardiovascular conditions will be far more complicated. But there is reason for hope: “Happily, clinical trials are on the horizon. Treatments for Parkinson’s disease are just a few years away from clinical testing. And some for Huntington’s disease may not be far behind.”
One of the reasons things have taken so long is the relative newness of the field: the discovery of embryonic stem cells, which triggered much of the explosion of research underway today, was just 16 years ago. Getting scientists to agree on standardized processes and protocols has taken time. The editorial points to early-days clinical trials for Parkinson’s that didn’t use standardized practices, leading to varying results that were an “uninterpretable mishmash.”
The editorial praises Parkinson’s Disease Global Force, which is bringing together research teams from Europe, the United States and Japan to define standards for cell preparation and patient selection and monitoring for future trials. The scientists will share their universally applicable results, which in turn will move the science forward toward finding treatments and cures.
In short, there will be more trials, fewer errors. And, in the not-too-distant future, new treatments.