Each month CIRM President Alan Trounson gives his perspective on recently published papers he thinks will be valuable in moving the field of stem cell research forward. This month’s report, along with an archive of past reports, is available on the CIRM website.
My reports the past few months have had many examples of people making valuable discoveries using stem cells made through reprogramming, so called iPS cells. This month has another. This one provides proof of the value of using iPS cells made from patients with genetic diseases to test drugs for toxicity in those patient populations. My colleague wrote about that work here.
But today I want to focus on a paper that surprised many people in the field, though I must admit that because it is work funded by CIRM I have been discussing it with the head of the research team for a year or more. During that time she ran exhaustive experiments to back up the findings. Those findings did initially induce head scratching because they were so unpredicted. The team led by Thea Tlsty at UCSF found a new type of cell in adult tissue that seems to be pluripotent in that it can make all kinds of tissues. But unlike a pluripotent stem cell, it is mortal; it stops multiplying and dies after a certain amount of time in a laboratory dish. You can keep pluripotent stem cells, either embryonic or iPS, growing in the laboratory indefinitely.
If other teams are able to replicate and verify this finding, these cells could potentially become a source of replacement cells for tissues from any of the three “germ layers,” of the embryo, for example to replace intestine, bone or nerves. Currently researchers working with adult cells for these repairs are limited to adult stem cells that can generally only make tissues from one of those germ layers. Much work lies ahead, but there is some possibility these cells could be a universal starting material for replacement tissue.
Thea’s team worked with breast tissue and, although they were able to isolate these unique cells, they found very few of them. Being quite rare, they could prove difficult to work with, so intriguing questions like whether they could be harnessed in the body where they reside naturally, could take a long time to answer.
My full March report is available online, along with links to my reports from previous months.