In a recent paper that spawned news articles and blogs worldwide, researchers announced the generation of human embryos that could produce stem cells. The announcement marks another step in the use of stem cells to treat a number of disorders, including diabetes, cancer, and neurodegenerative disease. But while this research, conducted by Dieter Egli, Scott Noggle, and their colleagues at the New York Stem Cell Foundation, holds much promise, it also demonstrates the daunting obstacles that block the path to stem cell therapy.
The biggest technical obstacle to stem cell therapy has been generating and isolating enough early-stage stem cells. It is these cells that have the greatest developmental potential because they can most readily differentiate into a mature cell that, in turn, could be used for cell therapy and regenerative medicine.
The discovery that adult cells could be “reprogrammed” into inducible pluripotent stem cells (iPSC) offered promises of stem cell therapy while sidestepping ethical issues arising from embryonic stem cell therapies. However, iPSCs presented technical issues that so far preclude their therapeutic potential. Bone marrow, cord blood, and adipose tissue also produce stem cells, but on an extremely limited basis.
So embryonic stem cells remain the “gold standard” (although iPSCs could still become the predominant technology). In their work, Egli and Noggle produced 13 embryos by transferring nuclei from the skin cells of diabetic patients into human eggs. These eggs surpassed previous attempts at human stem cell production; they could reach the 100-cell blastocyst stage (the earlier attempts never got past 10). What was the difference? The group transferred a diploid nucleus (from the somatic cell) into an oocyte that still had its haploid genome. Now, the cells could differentiate. But they did so with a triploid genome, a result that blocks their suitability for therapeutic use.
Some scientists feel this is an insurmountable obstacle. Others think that too many oocytes are needed to produce one viable stem-cell producing embryo (Egli and Noggin’s work needed 270 eggs to produce 13 embryos).
Clearly, cell therapy is becoming an important part of the pharmaceutical landscape, and the technical hurdles cleared by this research are impressive. But can the remaining issues be resolved? Can we ever get enough oocytes for therapeutic use? Will we ever be able to guide embryonic stem cell differentiation sufficiently to create every one of the approximately 230 cell types that make up the human body? Or will advances in iPSC research surprise us (as they have in the past)? Share your thoughts with us – we’d love to hear them.
Tags: human embryos and stem cells, stem cell research, stem cell therapy, stem cells, stem cells from embryos
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Now that the Molecular Med Tri-Con 2011 has ended and attendees are back at their offices, labs, practices, and/or hospitals – or perhaps have landed at their next business meeting or conference destination – it’s a good time to reflect on some of my general observations from the event.
The conference covered so much information that it would be impossible to review every topic. Following are a few areas that captured my attention and remain in my thoughts:
- STEM CELLS – There was a lot of focus on induced pluripotent stem cells (iPSC), in particular how to better characterize and understand those cells. Pluripotent stem cells can differentiate, or change, to become any one of the many types of cells that make up an organism. These cells are already being used for applications such as drug testing and drug screening. Once they are induced to re-differentiate, iPSC can provide good models for disease: what some conference speakers referred to as a “disease in a dish.” Some discussion among presenters focused on the idea of isolating cells from patients, producing iPSC, and then reintroducing the produced cells into the patient to replace cells that have been damaged or lost as a result of disease – an elegant form of cell-based therapy. Although widespread use of this approach is likely a ways off, I’m both optimistic of the therapeutic potential and somewhat cautious because of regulatory hurdles and potential safety issues (including some data showing tumor production in animals).
- CIRCULATING TUMOR CELLS (CTC) – This field of study is moving very, very rapidly. There’s immense scientific and medical interest in the clinical utility of these cells – as diagnostic biomarkers or as prognostic markers of disease recurrence. Also, as we’ve written before, there’s an emerging trend not just to count, but also to characterize CTC (which could increase their diagnostic utility, according to many conference presenters). Further characterization will provide information that will enable physicians to guide the treatment of patients in an increasingly personalized way, which is a very attractive idea. Also on CTCs: Discussion occurred on the need to isolate and characterize more types of cells (beyond those from epithelial tumors; “epithelial” = outside layer of cells that covers open surfaces, including skin) and to broaden the definition of CTC to include other types of rare, circulating cells.
- DNA SEQUENCING – One of my favorite topics, DNA sequencing, was a focus area at the conference. Jonathan M. Rothberg, Ph.D., Founder, Chairman & CEO of Ion Torrent (recently acquired by Life Technologies) described the most recent version of his company’s sequencing instrument. He shared an anecdote of how their instrument was used to sequence the genome of Gordon E. Moore, founder of Intel, who developed Moore’s Law (which states that the number of transistors on a chip will double about every two years). Rothberg explained that he and his company have been inspired by Moore’s Law and by Moore himself, noting that the Ion Torrent sequencer is based on semiconductor technology that uses electrons rather than light as the readout – so the sequencing of Moore’s genome takes science in a full circle. As for the next step in DNA sequencing, the big issue appears not to lie in generating the sequence data itself, but rather in the analysis and interpretation of the data. We have now realized the $10,000 genome (and the $1,000 genome is very close), but there was a lot of talk about the need to interpret all of that data, and much tongue-in-cheek reference to the “$1M analysis,” which reflects widespread concern about the magnitude of the challenge associated with making full use of the data.
- INFORMATICS: As a result of sequencing and other data-delivering trends, there’s now a great deal of effort underway to manage extremely large volumes of data and information. One trend discussed at the conference is the application of cloud-based computing to provide horsepower to analyze these complex data sets, to query large databases, and more. Virtual computing clusters may allow for widespread analysis by researchers who might not otherwise have sufficient computing infrastructure at their fingertips.
I could go on and on here, but I think you get the idea. Technology is advancing so rapidly that the landscape looks a lot different than it did even six or eight months ago. As a result, people are thinking of applications in health care differently, which is a great thing.
We would love to hear your thoughts on both the potential for and challenges of new technologies to affect the delivery of health care. Please use the comments link below.
Tags: circulating tumor cells (CTC), DNA sequencing, gordon e. moore, informatics, intel, ion torrent, life technologies, molecular med tri-con 2011, moore's law, personal genomics, stem cells
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