The Niche

This letter, from Francisco Silva, President of DaVinci Biosciences, responds to a Nature Reports Stem Cells article on one of his research papers as well as subsequent correspondence.

In response to PrimeGen Biotech’s letter to NRSC, I would like to make it clear that my comments regarding PrimeGen Biotech’s position on publishing were in no way meant to imply that their strategy was wrong. Cell based therapeutics is a very challenging and competitive industry, developing a technology in the laboratory and translating it into human application is very difficult. During my tenure as Executive VP of Research and Development at PrimeGen Biotech, my primary responsibilities were to identify and develop new technology which is demonstrated by PrimeGen Biotech’s intellectual property portfolio with seven patent applications.

With PrimeGen Biotech’s revamping of their R&D management as per Dr. Izadyar, I look forward to seeing them in clinical application next year. After all, "Our goals are ambitious--we believe with this therapy, we can be in clinic in 2010," said PrimeGen president John Sundsmo in an interview. [Editor's note: Fari Izadyar emailed on June 6 to say that John Sundsmo left PrimeGen during the revamp.]

I would like to thank Dr Schwartz for his remarks. At the time of entering our clinical study for spinal cord injury (SCI), we understood that it would have been ideal to include a control group, but being that this was a safety and feasibility study, the safety of the patients came first.

Continue reading "Correspondence: Response to article on spinal cord study" »

Posted by Monya Baker on June 05, 2009
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The following letter, from University of Tokyo's Hisashi Moriguchi, responds to a recent news feature in Nature describing the scientific race for the assessment and production of induced pluripotent stem cells.

In your News Feature 'Fast and furious' (Nature 458, 962–965; 2009), the safety issues concerning induced pluripotent stem (iPS) cells are well summarized. However, reviewing some published manuscripts for iPS cells, I have found that the reports on the cells' safety are very different among nations.

The follow-up data needed to evaluate the cancerous transformations of iPS cells have been shown in most original manuscripts from Japan (Cell 131, 861–872; 2007. Nature Biotechnol. 26, 101–106; 2008. Science 321, 699–702; 2008). On the other hand, such follow-up data have not been provided in most manuscripts from other nations (Nature 458, 766–770; 2009. Science 324, 797–801; 2009).

Now, new technologies to lower the risk of cancerous transformations by iPS cells have been reported (Nature 458, 962–965; 2009). However, which of the technologies most consistently produces the iPS cells with the least chance of tumourigenicity? The evidence has not been shown.

Continue reading "Correspondence: iPS cell safety data needs tracking" »

Posted by Monya Baker on June 04, 2009
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The following letter, from Primegen's Fari Izadyar, responds to comments made about PrimeGen by former executive Francisco Silva in a recent article in Nature Reports Stem Cells.

We wish to comment on certain aspects of the interview with Francisco Silva published in Nature Reports Stem Cells (9 April 2009), which accompanied an analysis of his recent publication. First, we applaud Dr Phil Schwartz's rigorous discussions on the sham surgery effect of untethering the spinal cord and removing scar tissue, and the acknowledgement of both the placebo and the potentially therapeutic physical effect of the manipulation, which is separate and distinct from the cell therapy component. In other words, with so much noise, how does one see a signal in such a small uncontrolled study?

In the article, Francisco Silva described our company as having "...a corporate strategy regarding publishing their work, which differed from my belief that peer review is required and needed process providing validation and transparency. As a result, I left [the company] in 2007."
In the interview, PrimeGen Biotech was erroneously described by Silva as having a corporate strategy that did not believe in validation, transparency or the peer review publication process. Our company has a demanding corporate policy for a rigorous and careful validation process prior to publication of our results, and, contrary to Silva’s claim, our company has published research in respected peer-reviewed journals, such as Biochemical Biophysical Research Communication, Reproduction, Human Reproduction and Tissue Engineering and Regenerative Medicine (in press). Silva is one of the senior authors on two of these papers, which were submitted prior to his departure, and this clearly demonstrates that peer-review publication has always been an important part of our corporate policy and directly refutes Silva’s claims.

Continue reading "Correspondence: Primegen supports peer review, transparency" »

Posted by Monya Baker on June 04, 2009
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Horst-Dietrich Elvers, Burkhard Jandrig, and Christof Tannert write:
The Nature News story “Simple switch turns cells embryonic” (Nature 447, 618-619; 2007) presents the results of three independent research teams showing that normal skin cells can be reprogrammed to an embryonic state in mice. If this can be successfully adapted to human cells, the creation of human germ cells out of these pluripotent cells should be possible (as was indicated already by Huebner et al. Science 300, 1251-1256, 2003). Now, the road seems to be prepared to create human tissues for therapeutic purposes without using or destructing human embryos. This is, doubtless, an important progress for the whole field of regenerative medicine and avoids many morally questionable decisions, which so far have led to an international mix of regulatory frameworks. Therefore it is not surprising that excitement is overall huge at the moment.
The published results seem to indicate that the ethical problems of human embryo research are solved now.

Continue reading "Reprogramming breakthrough does not displace ethical debate" »

Posted by Monya Baker on July 09, 2007
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In June, widely publicized work from three labs showed that specialized cells could be reprogrammed after transfection with four genes. In this correspondence, James Trosko suggests an alternative explanation, that the reprogrammed cells identified by groups led by Shinya Yamanaka, Rudolf Jaenisch, and Konrad Hochedlinger and Kathrin Plath could in fact be skin stem cells reprogrammed to an embryonic state.

Another thread discusses how reprogramming work alters perceptions of whether dedifferentiation is active or passive, and adds insight from in silico modeling. http://blogs.nature.com/reports/theniche/2007/07/reprogramming_insights_in_sili.html

Below is the email correspondence between the scientists:

Continue reading "Do induced pluripotent stem cells arise from skin stem cells?" »

Posted by Monya Baker on July 09, 2007
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Eric Werner writes:
The recent results of dedifferentiating adult mouse fibroblast cells into stem cells brings into focus the fundamental question of how differentiation and development are controlled. (Cyranoski, D., Nature 447, 618-9; 2007). (Okita, K., et al. Nature doi 10.1038/nature05934, 2007). The fact that just four regulatory genes inserted into cells using viral vectors, can transform normal, differentiated cells into pluripotent stem cells indicates that for some cell types, at least, the process of dedifferentiation is more a process of activation rather than deactivation (Reik, W., Nature 447, 425-32; 2007). Indeed, this falls in line with in silico studies where stem cells, and, more generally, multicellular differentiation and development are modeled on computers.

Continue reading "Reprogramming insights: in silico modeling suggests active dedifferentiation" »

Posted by Monya Baker on July 09, 2007
Categories: Correspondence, Reprogramming/Pluripotency | Permalink | Comments (0) | TrackBacks (0)