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Last ISSCR 2009 post: thanks to many and congratulations to the poster winners

This month marked the 7th ISSCR meeting for the society and the third for me, and as always, there was much more news worth covering than bandwidth to do so.

I had some help this year, the result of an experiment asking for volunteer writers to send me summaries of the sessions and posters they found most interesting. These posts (you can find them by searching ISSCR or “conference blogs”) made the coverage this year fuller and wiser. I am very grateful for the contributions of Julie Clark, Andrea Ditadi, and Teisha Rowland. Also, thanks to professor Jeanne Loring for her comments on the write-up of Yamanaka’s talk, showing that iPS cells derived from different cell types behave differently.

If a dark-haired 30-something woman sidled up to you in Barcelona with an onslaught of questions (“What was your favorite session? Did you believe that last talk? Is X an established concept or a new idea?”), that was probably me. Thanks everyone for patiently sharing your knowledge, tips and insights. You literally make my job worth doing.

I also know there is a lot more to do. As we walked out of the last talk on the last day of the conference, I asked the outgoing society president Fiona Watt for some of her clearest memories of the past year. She was cheery at the conclusion of a meeting that she’d felt had gone well (our conversation was continually interrupted by attendees offering her handshakes and congratulations). Still, one of her comments struck me as a growing problem:

“Things obvious to one section of our community are not obvious to others.”

Finally, though I had nothing to do with it, I know several scientists put a lot of time into assessing and picking poster winners. I’m sure you’ll see some of this work in the peer-reviewed literature before too long. In the meantime, here’s a sneak peak.

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p53 at ISSCR: not just for cancer anymore

Most scientists who think about p53 are probably working on cancer rather than pluripotency, but a suite of talks is putting that protein on stem cell biologists’ radar.

At ISSCR, Shinya Yamanaka of Kyoto University presented data showing that both p21 and p53 offer barriers to reprogramming: attempts to reprogram fibroblasts that lack p53 are much, much more efficient. Konrad Hochedlinger at Harvard described similar results. Hochedlinger and others have created iPS cells with inducible versions of pluripotency genes, then used them to generate mice whose cells already contain the genesnecessary for reprogramming; no new viral transfection needed. Shockingly, though, activating these genes in fibroblasts made from these ‘reprogramming-ready’ mice does not yield very efficient reprogramming rates. However, Hochedlinger’s lab found that if p53 is knocked out in these secondary cells, the reprogramming rates soar to over 80%. Hochedlinger has been experimenting with genes associated with senescence (INK4a/ARF) as well as blood cell types at varying stages from senescence. He found that, generally, the further a cell is from the senescent state, (i.e. the more divisions it has left in it) the more efficiently it reprograms.

Jacob Hanna from Rudolf Jaenisch’s lab at the Whitehead presented results adding another insight to these finding. He and his colleagues worked with several passages of blood cells that already contained insertions of pluripotency genes. They found that, given enough time, just about any cell can be converted to pluripotency. Suppressing p53 clearly has the power to boost reprogramming rates, possibly because the knockdown of p53 causes cells to divide twice as fast for reasons likely to be linked to the cell cycle. (But of course, other explanations will be found elsewhere. Hanna, for example, also found that overexpressing Nanog accelerates reprogramming independently of accelerating cell cycle.)

The first publication I’m aware of that linked p53 to the efficiency of induced pluripotency was by Hongkui Deng in Cell Stem Cell in November last year. It’s certainly not going to be the last.

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ISSCR 2009 meeting: what’s changed from last year?

I asked that question over and over. Common responses were that discussions of iPS cells were less prominent (except at the poster sessions) and talks about tissue-specific stem cells more so. People I spoke with generally felt there was greater variety in topics and presenters than they’d seen before; though at least one felt there was an over-reliance on “ISSCR’s established speakers.” Several thought the meeting, which at around 3,100 attendees was the biggest yet, was growing too large, making attendance a good way to get an overview of related specialties and network, but not as effective for keeping up in one’s own field. General consensus was that most talks described recently published or accepted work. There was a lot of new content in two very jam-packed poster sessions, together exhibiting well over 1000 posters (the numbers went into the 1750s!)

I can't convey all the conversations I had, but I include snippets from Ruth McKernan, Doug Melton, Allan Spradling, Mahendra Rao below.

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ISSCR sessions from Barrandon and Mikkola: thymus makes skin, SCL starts up HSCs

Note: These accounts of talks given at ISSCR were written by Andrea Ditadi.

Yann Barrandon: Thymus cells make skin, hair follicles

The skin, vagina, cornea, esophagus and other organs in contact with external environment, no matter their germ layer of origin, are all covered with stratified epithelium. Such epithelium is characterized by cells that undergo constant self-renewal. Yann Barrandon of Lausanne University Medical School reported some years ago that this long-term renewal was due to a population of multipotent, clonogenic stem cells. (Claudinot et al 2005, PNAS). These cells persist in niches and proliferate according to environmental cues. In vitro, these stem cells form colonies that can be serially cultured and transplanted. They can also generate all epithelial structures, including the hair follicle and sebaceous gland. Cells from the stratified epithelium of different tissues express a common pattern of genes. The thymic epithelium, which does not come into contact with the external environment, is not as well studied.
Reports that the cell-cycle regulator p63 is required for both stratified and thymic epithelium to develop suggested that they may share a similar progenitor. When Barrandon focused his attention on thymic epithelial cells (TEC), he found a subpopulation of rat TEC (0.1-0.5%) that are clonogenic and can be serially passaged. Those TEC progenitors can be recovered from both embryonic and postnatal thymuses.
In contrast to progenitors in stratified epithelium, cultured clonogenic progenitors generally maintain their “thymus identity” but also express epithelial/hair markers. Barrandon combined epithelial cells from both skin and thymus and transplanted these under the kidney capsules in immunodeficient mice. However, while epithelial progenitors cannot contribute to thymus development, thymic TEC progenitors can form thymus as well as skin and even complex skin structures like hair follicles.
In a serial transplantation experiment, recovered TEC progenitors from secondary recipients retain a thymic “signature” expressing almost all the ordinary thymic genes. All the results Barrandon showed suggest that thymic epithelium may contain a very immature multipotent epithelial progenitor with a broader spectrum of potential than epithelial stem cells. And it can be speculated that thymic and stratified epithelia derive from the same precursor, even though their position and function are totally different. In any case, understanding how the skin forms complex structures could lead to improvements in skin grafts and treatments for other skin diseases.


Session info
Barrandon Yann
Lausanne University Medical School and Ecole Polytechnique Fédérale Lausanne
IMPACT OF MICROENVIRONMENTAL CHANGES ON EPITHELIAL STEM CELL FATE
Plenary 36. Growth Control in Stem Cells and Cancer Plenary V

Getting HSCs started with transcription factor SCL

Gereige Laurraine, a student in Hanna Mikkola’s lab at UCLA brings new light on the function of SCL/Tal1, a well known transcription factor required for hematopoiesis. Though mouse embryos lacking the gene for SCL die 9.5 days postconception for lack of blood cells, SCL appears dispensable thereafter for hematopoietic stem cell (HSC) development and function.

Laurraine first used ES cells to create hemangioblasts, precursors of both hematopoietic and endothelial cells. To discover which genes SCL targets, she performed Chip-on-chip analyses to compare cells that both expressed and lacked the SCL gene. These analyses indicated that SCL plays a dual role: it activates major hematopoietic transcription factors that promote the development and maintenance of HSC, and it represses transcription factors critical for the specification of other mesodermal fates. (More specifically, SCL activates factors including Gata2, C-myb, Fli1, Lyl1, Tel, Gfi1, Sox17, and represses factors including those that promote cardiac lineages [Gata4, Tbx20] as well as mesenchymal lineages [Foxf1a, PDGF-R-alpha].) Analysis of the acetylation and methylation of candidate SCL target genes in the ES-cell derived hemangioblasts confirmed the activation of hematopoietic genes and the repression of alternative mesodermal ones.
Laurraine was able to abolish SCL expression at a later point in development (She used a Cre-lox system tied to the expression of hematopoietic marker vav). She showed that the number of adult HSC (isolated as murine Lin- ckit+ bone marrow cells) was not affected, and that other HSC genes like Lyl1, Gfi1, C-myb were still expressed even in the absence of SCL. Her results confirm that, once hematopoietic specification occurs, the SCL-induced hematopoietic program is stable even without SCL.
In addition, Laurraine suggested that Lyl1, a factor in the same family as SCL, may maintain the hematopoietic program in the absence of SCL. Indeed, contemporary absence of Lyl1 and SCL leads to a complete absence of HSC. In the model she proposes, SCL plays a major role in the emergence of HSC before E10.5, Lyl1 maintains the SCL induced transcriptional program in HSC/progenitors until birth, and both can maintain the cells after birth.

Session info
Gereige Laurraine, UCLA, Los Angeles, CA, USA,
SPECIFICATION AND MAINTENANCE OF THE SCL INDUCED HEMATOPOIETIC STEM CELL FATE
Concurrent 42. Concurrent Session IIB: Stem Cell Fate Choice

These accounts are by Andrea Ditadi, a postdoctoral fellow studying stem cells at Hopital Necker – Enfants Malades in Paris.

Note from Niche editor This post comes as a response to my solicitation in June calling for people to submit their accounts of ISSCR 2009. I’d asked people to describe what most interested them and to disclose any conflicts of interest. I’m very grateful for these volunteers’ help making more information available.

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ISSCR Friday posters: cell-penetrators, differentiators, memory-storers, and more

NOTE: These write-ups of selected ISSCR posters are by Teisha Rowland, a volunteer Niche blogger and student at UC Santa Barbara.

They include the following:
Culturing MSCs in spheres may boost their differentiation capacity (Bray, Schilling, Burdon, Genever)
Small-molecule primer for ESC differentiation (Zhu, Wurdak, Wang, Schultz)
Alternative to iPSCs: sometimes fusion goes faster (Schneider, Zenke, et al)
A silky cell-penetrating protein for producing iPS cells (Park, Park, Park)

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Business round-up: pluripotent products, all-star academics and headlines everywhere

Academic all-stars from the East and West Coasts of the US have united to advise a company with plans to use induced pluripotent stem (iPS) cells to find drugs. The company, created from the merger of Boston-based Perian and San Francisco-based iZumi, will be called iPierian and run by iZumi CEO John Walker from San Francisco.
See account in FierceBiotech and Q&A with John Walker about iZumi’s business plan (subscription to Nature Biotechnology required)

It’s not just the name that’s new:

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ISSCR plenaries: how to repair 1) a salamander leg and 2) a human airway

NOTE: These two write-ups are by Teisha Rowland, a volunteer Niche blogger and student at UC Santa Barbara.

Limb regeneration takes nerve

Proper limb regeneration in the salamander requires the presence and function of nerves, although it is unclear why this is on a molecular level. Recent evidence implicates a newly discovered protein as having a central role in the innervation of regenerating limbs.

At ISSCR in Barcelona, Jeremy Brockes of the University College London reported that in severed salamander limbs the protein n(ewt)AG, or nAG, is key for promoting regeneration. nAG production, in turn, is linked to nerves in severed limbs.

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ISSCR posters: In vitro stem cell culture: are we doing enough to make the cells feel at home?

This account is by Julie Clark, a Field Application Scientist at Stemgent in San Diego.

Some five dozen abstracts published for ISSCR this year included the word “oxygen”. Each highlighted the benefits of low oxygen (0.2-10% O2) for embryonic, hematopoietic, and mesenchymal stem cell culture. Indeed a steady stream of publications describes how hypoxia inducible factors and reactive oxygen species affect stem cell self-renewal and differentiation. This makes scientists wonder what might be missing in standard in vitro culture conditions.

A discussion with Jit Hin Tan from MIT highlighted the need for continuous hypoxia: Oxygen diffuses from the media surface to the attached cell layer, creating an oxygen gradient over a period of 24 hours. Exposure to atmospheric oxygen can undo this gradient within minutes. Kristiina Rajala from the Karolinska Institute found that low oxygen tension prevented spontaneous differentiation, increased proliferation and supported self-renewal of human embryonic stem cells (hESCs). Sandra Varum from the University of Texas described an alternate way to achieve some effects of low oxygen: antimycin A could mimic the enhanced pluripotency effect of hypoxia by inhibiting complex III of the mitochondrial respiratory chain, thereby reducing oxidative phosphorylation.

Diverse labs have thus identified benefits of hypoxia to cell culture. But, getting these benefits comes at a price. The cost of a hypoxic-incubator closed system starts at $70,000 (about 50,000 Euros). Given the success of culture under atmospheric conditions, researchers will have to think hard about whether to replicate in vitro the low-oxygen atmosphere that cells encounter in vivo.

Note from Niche editor This post comes as a result to my solicitation in June calling for people to submit their accounts of ISSCR 2009. I’d asked people to describe what most interested them, not to write about their own or their collaborators’ work, and to disclose any conflicts of interest. I’m very grateful for these volunteers’ help making more information available.

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ISSCR session: Consistent differences in ES and iPS cells

This account is by Teisha Rowland, a student at UC Santa Barbara who uses hESCs and iPSCs. She runs a blog called allthingsstemcell.com

Physiological differences have not been reported between embryonic stem cells and induced pluripotent stem cells, but new work shows consistent gene expression differences between them. One of the biggest questions in the field has been how similar these cells really are. If there are differences, are those due to suboptimal techniques for making iPS cells, or the fact that iPS cells don’t come from an embryo?
At ISSCR in Barcelona, Kathrin Plath of UCLA reported that there are some distinct gene and miRNA expression differences between them. She compared four iPSC lines made using different methods and found that 15 genes that are consistently expressed in these lines have significantly different expression levels in ESCs. In particular, basic cellular processes are down-regulated in iPSCs compared to ESCs, while regulation of genes involved in differentiation is up-regulated. Plath suggests that this may be because the fibroblasts from which the iPSCs are made aren’t sufficiently reprogrammed. Interestingly, late-passage iPSC gene and miRNA expression more closely resemble the ESC profile than the early-passage iPSC does, in Plath’s analysis. Plath hypothesizes that this may be caused by selecting iPS cells that most resemble ESCs over many passages. Ultimately, Plath suggests that iPSCs should be thought of as a different type of pluripotent stem cell, distinct from ESCs.
See also Plath’s recent publication in Cell Stem Cell
Session and write-up info
Speaker: Kathrin Plath
Talk title: Mechanisms of Transcription Factor-Induced Reprogramming
(Thursday, Concurrent Session I, Track A)

Note from Niche editor This post comes as a response to my solicitation in June calling for people to submit their accounts of ISSCR 2009. I’d asked people to describe what most interested them and to disclose any conflicts of interest. I’m very grateful for these volunteers’ help making more information available.

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Why Yamanaka’s new results don’t (necessarily) spell doom for most human iPS cells

The stem cell field needs developmental biologists not just to use iPS cells, but to pick the best ones. As Shinya Yamanaka finished his talk Saturday morning, I literally felt cold. He’d compared dozens of mouse ES cell lines with iPS cell lines generated from mouse embryonic fibroblasts, tail tip fibroblasts (TTFs), hepatocytes, and even a few lines from stomach tissue. The tail-tip fibroblasts were bad news: they resisted differentiation. Even after in vitro differentiation caused the cells to make neurospheres twice, tail tip fibroblasts injected into mouse brains did not persist calmly as brain cells but instead made big, scary teratomas. Other assays came to similar conclusions. Of course, not every line misbehaved, but the TTF lines were much more likely to do so than the others. (You can read more of the results in Nature Biotechnology )

Right now, Yamanaka said, the only certain conclusion from the results is that researchers need better ways to evaluate iPS cells. But the implications are disturbing: mouse non-embryonic fibroblasts behave badly as iPS cells, and most human iPS cells come from adult fibroblasts. Have researchers been making exactly the wrong sort of human iPS cells? Yamanaka said it was too early to draw this conclusion. “Humans don’t have tails,” he said.

It turns out that’s not such a trivial observation. Among the scientists I cornered after the talk was Juan Carlos Izpisua Belmonte, who has shown that keratinocytes make iPS cells more readily than fibroblasts. “Has everyone been making cells from the wrong tissues?” I asked him breathlessly. He was calm. The tail, it turns out, is one of the last structures to form during development. Cells there retain plasticity long after cells elsewhere have specialized. Like Yamanaka said, more work needs to be done.

Much of the insight for what this work should be will come from scientists’ instincts to eliminate variables. All the lines Yamanaka tested were generated independently. The number and places where the extra pluripotency genes inserted themselves could vary greatly. Making iPS lines from “reprogramming ready” mice might help to ascertain whether its the tissue of origin or the luck of insertion that determines cells' behavior.

Other insight, like Belmonte’s, might come from developmental biology. It made a conversation I’d had just the day before with Allan Spradling ring even truer.

But I have no time to write about this right now. Nor can I discuss the barriers to reprogramming that are being identified and knocked down by Konrad Hochedlinger and others, nor the ever more companies springing up around iPS cells. I’ll do it (and more) in airports as I head home to San Francisco. I also have some posts written by young scientists to add. If you’ve got some other ISSCR links or tidbits, please let me know.

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Thursday at ISSCR

Yesterday, I wandered around the poster session asking for favorite talks, and though my sample was only about 10 attendees, a few speakers’ names recurred. Much of this has been published or will soon be.

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Uncertainty surrounding NIH stem cell guidelines

At the ISSCR meeting in Barcelona, Harvard’s Kevin Eggan told reporters he isn’t sure that any human embryonic stem cells are eligible for U.S. federal funding right now. The principles of the just-released US NIH guidelines are clear on what’s fundable; the details are anything but. And until those details are unclear, Eggan and others are worried that some institutions won’t let researchers use resources acquired with federal dollars; another worry is that institutions won’t let awarded NIH grant funds flow to researchers.

Over the upcoming months, a group of to-be-assembled experts must decide what existing ES cell lines will make it onto an NIH registry of lines that can be studied with federal funding. This means, among other things, convincing the experts that the embryos donated for the creation of the lines were obtained with appropriate informed consent, according to accepted criteria at the time. The older forms are not as good, and some institutions’ forms are better than others, that could, perhaps, lead to a backlash against certain lines. (See When the past catches up with the present ) To mitigate this problem, research institutions could proactively move to reconsent as many donors as they can; having such documentation at the ready could help the NIH expert groups move more swiftly.

Additionally, some research may just fall through gaps of bad timing. For instance, lines created after July 7 must follow specific guidelines in the new criteria. That could mean that some embryos already donated for research can’t be used for making lines because some in vitro fertility clinics haven’t yet modified their forms and procedures.

Clearly it is not President Obama’s intention for the NIH to stall human embryonic stem cell research. The NIH has told researchers it will act expeditiously. But the Institutes also cannot be a rubber stamp; the public must be able to trust the NIH to hold researchers to carefully considered criteria. As Eggan said about moving stem-cell technologies from the laboratory into the clinic: “the fastest way is the careful way.” The NIH should act expeditiously, but it should also take the time it needs to assemble the registry rigorously.

In the meantime, individual institutions will be left in an uncomfortable position of deciding what research they will permit. Research institutions understandably shun the possibility of bad publicity. But, in the absence of compelling new reasons, they should be equally committed to standing behind research that has already passed the scrutiny of ethics committees.

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Germ cells, neurogenesis, and more ISSCR's first day

I asked program committee chair Ron McKay for the highlights I should look for over the next few days of the ISSCR. He tactfully declined to mention individuals. Instead he said was particularly proud of the diversity. “There’s no single agenda here,” he said, “no club.”

So, perhaps it’s not too surprising that no clear highlight has emerged yet. At tonight’s reception, I asked everyone I met to summarize his or her favorite talk, and though there have been only ten talks so far, no single one is emerging as most popular. Here’s a summary: (I’m borrowing phrases from people I spoke with.):

Marianne Bronner-Fraser from CalTech said that epigenetics, in particular histone methylation, seems to control the settings within the gene regulatory networks governing neural crest cell development and migration.

Rusty Gage from the Salk Institute said that adult brains may well be genetic mosaics. LINES elements seem to jump preferentially into neuronal genes in neural precursors. It’s not clear why this would be adaptive.

Elena Cattaneo from the University of Milan showed links between BDNF and the huntingtin protein.

Yukiko Gotoh of the University of Tokyo showed that Wnt and Polycomb proteins together function as a sort of time-keeper, so that the way that neural stem cells respond to external cues is regulated in time.

Azim Surani described multiple states of pluripotency in embryonic stem cells, embryonic germ cells, and epiblast cells. He described some of the complex machinery developing germ cells use as they prepare for totipotency (suppressing somatic programs, reactivating the X-chromosome and pluripotency genes).

Paolo Bianco of the Sapienza University of Rome said that mesenchymal stem cells are not all the same. Some express the muscle marker Pax7! Exploring these differences could help show how postnatal progenitors establish themselves in muscle and other tissues.

Elaine Fuchs of Rockefeller University described the exquisite players that balance resting and proliferation in the skin; Haifan Lin of Yale, how a whirl of RNA-RNA-protein interactions of varying stability) regulate gene translation, Nancy Wexler tooks us on her journey to identify the Huntington gene, Etienne Hirsch of INSERM described how, even as dopamine neurons in Parkinson’s models degenerate, other types of cells proliferate.

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Unfinished cathedrals, stem cells, and Barcelona

Yesterday I walked around Gaudi’s beautiful cathedral, Sagrada Familia, still under construction more than a century after it was started. In the vaults and columns, simple patterns and rules are played out in endless variations making beautiful, complex forms. (If you’re reading this blog, you likely thought of organogenesis instead of architecture.) Gaudi invented new techniques to plumb the limits of his craft: for instance, he made inverted models, in which weights hung from the ceiling revealed the load a column could bear.

So, persistence of vision, innovative models, and new applications of old ideas create Barcelona’s most-visited monument. But, if you’re in the right mood, there are parallels to stem cells. And of course, the field is still under construction.

What do stem cells have that Sagridia Familia does not? Epigenetics. I’ve been asking everyone what’s going to be big at this conference, and it’s not just the most common answer I’m getting, it’s practically the ONLY answer. How does a cell highlight its genome to know which genes to use? Can we intervene in this process? The stem cell community is just now learning how to figure this out.

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Companies have company at stem cell conference

I didn’t expect to find so much industry here, at this year’s World Stem Cell Summitt in Madison, Wisconsin. The companies are diverse, from giant New York–based Pfizer to teeny, tiny start-ups, and so are their goals. Pfizer is creating a new division of regenerative medicine, and the new head, John McNeish, spoke of plans to use stem cells to identify new drug targets and to screen drugs for toxicity and efficacy. They’ve already run over a million compounds through assays that used stem cells (I think mouse embryonic stem cells).

But he’s also excited about harvesting the therapeutic potential of stem cells themselves. It’s not cell transplants he’s thinking of, though, so much as finding small molecules (the type that can be made into pills) that activate stem cells within the body. Perhaps the tissue-homing skills of certain stem cells could even be used as drug-delivery devices.

Of course, Pfizer is not alone. McNeish had a lengthy list of other public announcements to establish pharma’s interest in stem cells. At the International Society for Stem Cell Research meeting in June, I met plenty of industry scientists hoping to pick up bench tricks for using stem cells, mainly as a way to test small molecules.

For the most part, the smaller companies here are selling services tocharacterize or grow stem cells. Companies might scale an established line of cells up under rigorously controlled conditions or provide reagents to make growing stem cells more convenient. At a panel, Jonathan Gertler, a boutique investment banker from Leerink Swann, in Boston, Massachusetts, predicted an expanding market for these kinds of services: as less experienced people enter the field, both the market and need for these tools will grow. He estimated that companies that are potentially commercially viable already number almost 100; consolidation is coming, he said.

As the possibilities for making money edge nearer, the real intellectual property fights will begin. And right now the patent situation is very uncertain, said Owen Hughes, who thinks about intellectual property and regulatory issues for Pfizer. Taxpayer-funded reach-through policies (I believe this was code for the California Institute of Regenerative Medicine), he says, only add to the uncertainty.

Greg Simon of the think tank FasterCures, based in Washington, DC, said fiefdoms would hurt science. “We can’t have every state build an infrastructure for intellectual property and then build a castle around it.” He also called for academics’ work with industry to be disclosed, not so much for concerns over conflict of interest, but because that information could be useful for everyone in the space. (There are loads of people who would like to know what reasons the FDA gave for halting Geron’s clinical trial; that way they might be able to better plan out the tests they need to do).

If anyone has ideas for sharing data in their own self-interest for stem cells, please let me know.

Related stories
See Embryonic stem cell trial put on hold

See Thickets and gaps blocking stem cell research


Pfizer dips a toe into cell therapy

Here are all three blogs from the conference

Companies have company

Stem cell trials balancing hope and harm

Stem cell therapies, ready for success?

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Stem cell trials: balancing hope and risk

In Madison, Wisconsin, the former US secretary of health bellows: “Some inner hope!” Tommy Thompson yells at the crowd—a room full of stem cell research advocates—preaching to the converted that embryonic stem cells give disease sufferers a reason to believe in a better life.

This is an unusual conference: patients and patient representatives plus industry executives, politically active scientists, lobbyists, ethicists, policy experts and more are here.

Although the conference organizer stresses that the meeting is not partisan, the crowd and some speakers are vocally anti-Bush because of his refusal to fund human embryonic stem cell research. Thompson tells the crowd that the policies could easily have been more restrictive and describes how Bush called in pro-research Thompson to debate anti-research Karl Rove on the issue. (The president munched a peanut butter sandwich during the impromptu but lengthy discussion; a few days after that he announced his compromise position to fund lines created before August 2001.) After relating the story, Thompson warns them not to be too harsh on Sarah Palin; they might need to work with her.

Later that afternoon, Alta Charo, a professor of law and bioethics at the University of Wisconsin–Madison, says debates over the moral status of five-day-old embryos are simple compared to what will come when cell-based products enter full-fledged trials for spinal cord injury and the like. She delineates problems with cell therapies, going from the difficult animal studies (monitoring cell transplants for months in infection-prone rodents) to the “polarizing debate around class and access to health care” that will ensue if an expensive cell therapy hits the market.

In between there is the hurdle of conducting clinical trials. When that happens, she predicts, the number of patients hoping to participate in trials far exceeds the number that can be enrolled.

Indeed, one of the scientists here told me privately that the constant invocation of "the 'C word'" (cure) made him uncomfortable. Even if cell-based therapies help, most are a long way from being tested, and they are more likely to improve a patient’s condition than to reverse it.

The exuberant attitude worries scientists, but it’s part of US culture, says Charo. The American mindset is optimistic and forward thinking. That means US patients often assume that 'the new thing' must be better than the current standard. “Without controlled trials, we can be sorely misled. People can undergo terrible ordeals for something that might be worthless.”

This is something that Wise Young thinks about nearly every waking moment. The neuroscientist from Rutgers University, in New Jersey, has courted controversy by reaching out to help organize stem cell networks in China and elsewhere, urging commercial practitioners to disclose their procedures (some refuse). Patients would go anyway, he says, despite the high cost and risk. “No matter what we do and what we say, medical tourism will occur until we start providing something that will satisfy the demand.”

Young calls for greater willingness to do clinical trials in the United States and for scientists to talk with and monitor patients before and after they go abroad for poorly documented procedures. Anecdotes are very hard to assess, particularly for spinal cord injury. Over time, patients’ conditions do tend to improve somewhat, and performance can vary significantly from month to month.

A coordinated group of scientists who would assess patients at multiple time points before and after they undergo procedures could provide invaluable information, even in the absence of a clinical trial, suggests Graham Creasy, chief of Spinal Cord Injury Service at the VA Palo Alto Health Care System in California. Indeed, this has been done on a smaller scale already, one for a clinic in Portugal, another for a clinic in China. An evaluation showed no significant improvement in patients’ condition. But there are problems with the approach. Medical experts in the United States worry that even this kind of inquiry could legitimize and thus encourage potentially harmful approaches that disqualify patients from future trials in the United States. Besides, what incentive would the medical tourists have to participate in these inquiries?

BTW: The International Campaign for Cures of Spinal Cord Injury Paralysis provides information for the general public on participation in clinical trials. (This is different from paying money to a far-off clinic for undocumented procedures, but similar questions apply.)
The International Society for Stem Cell Research has proposed draft guidelines for the clinical translation of stem cells and is seeking comments until the beginning of October.

Related stories
Stem cell society condemns unproven treatments

Stem cell researchers face down stem cell tourism

Here are all three blogs from the conference

Companies have company

Stem cell trials balancing hope and harm

Stem cell therapies, ready for success?

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Stem cell therapies, ready for success?

Stem cell researchers have a new worry. What happens if the cell-based therapies actually work? “We could have a cure, but there might be a backlash, because we aren’t ready to the economic impact of that ability.” That’s the question that John Wagner asked the 900 or so attendees at a stem cell meeting in Madison, Wisconsin.

It’s a problem that I’d heard before, but from social equality activists who did not feed cells or treat patients. Now, that worry is being posed by practicing scientists. The argument that the World Stem Cell Summit is about research advocacy and infrastructure simply doesn’t hold. The topic came just last week at a meeting designed for scientists to address other scientists.

I hadn’t seen it coming. I was moderating a panel of prominent scientists (Alan Trounson, Arnold Kriegstein, Christine Mummery, Larry Goldstein), and as a soft-ball final question I asked what issues the field would have to address in the future. How society could pay for therapies came up again and again.

I’m puzzled. Is this a sign that scientists and social activists are interacting in new ways. Funding from patient advocacy groups is now essential for many scientists to run their own labs. Is this a sign that researchers believe the therapies can work? Certainly the hurdles are getting more and more detailed, and we’re hearing more emphasis on more-immediate applications of stem cells, such as disease modeling and patient screening.

It’s becoming a truism that for stem cell therapies to work, there will need to be more collaboration between academics, clinicians, patients, regulators, and industry. Now, health care payers and activists may get added to that list.

Here are all three blogs from the conference

Companies have company

Stem cell trials balancing hope and harm

Stem cell therapies, ready for success?

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ISSCR Round-up Take 2

Alexey Bersenev just sent in his detailed take on the ISSCR meeting, in which he also compiled a list of other blogs on the meeting. Thanks!

Just to keep the Nature comments on ISSCR in one place, here’s another list.
My speed-writing on impressions from ISSCR.
Nature’s Brendan Maher posted on Doug Melton’s talk on reprogramming in situ. Who needs pluripotency? Let’s go straight to the cells we need!

How do you know a reprogrammed cell is reprogrammed?
Scientists consider minimum standards for induced pluripotent stem cells
My blog post on the same topic links to articles on iPS cell advances.

Stem cell society condemns unproven treatments
The ISSCR is drawing up guidelines for clinical practice. How will patients and practitioners respond?

Read our feature Stem cell researchers face down stem cell tourism

Also, just weeks before the ISSCR meeting, stem cell researchers gathered for their version of summer camp, Cold Spring Harbor Laboratory Symposium, where the ratio of content learned
Read my impressions.

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ISSCR in Philadelphia

This from Brendan Maher is cross posted from In the Field
Harvard’s Doug Melton, in a plenary talk this afternoon to open the International Society for Stem Cell Research (ISSCR) meeting in Philadelphia, actually didn’t talk about stem cells at all. Rather he discussed new results showing direct differentiation of pancreatic It was clear from the opening session, that a large part of the conference would focus not on the derivation of stem cells, but rather their re-differentation into useful tissues, which is not so easy as one might think. Take the beta cell for example. Melton has had a long-standing project to derive beta cells from es cells. The potential is obvious. For folks with type 1 diabetes, beta cells can be transplanted with limited success, but are currently in short supply (cells from two cadavers are required for the so-called Edmonton protocol).

After four years of work trying to use chemical compounds to edge stem cells down the developmental path of the insulin producing beta cells, he found two with 70% efficiency in moving the cells the very first step in a process that looks to contain maybe six. So, his group began experiments to short circuit the process. Rather than taking an undifferentiated stem cell, could one take a fully developed adult cell and switch its fate using transcription factors without reverting to stem cells? The answer, ostensibly seems to be yes. Screening for upwards of 1000 factors in 5000 mouse embryonic tissue samples, Melton’s lab identified 28 factors that appeared closely related to beta cell differentiation formation. Paring down brought the number to nine. Using a virus to inject the genes that encode these transcription factors into the pancreas of living mice, they were able to cause exocrine cells in the pancreas to start producing insulin and look just like beta cells in every way they’ve looked. Melton says, it’s “not the case that they’ve just turned on the insulin genes. There’s a panoply of genes turned on and off in response to these transcription factors.” They even started producing VEGF and promoting angiogenesis to get blood supply. The group has been able to reliably convert cells to insulin producing beta cells using just three of the nine genes: Ngn3, Pdx1, and Mafa. Mice in which islets had been chemically ablated achieved some level of blood sugar control, but not that of wild type. And despite waning expression of the three genes they injected, the phenotype of the transformed cells remained for several months. Melton says he wouldn’t necessarily predict a gene therapy approach based on his findings, but if in vitro technologies could be adapted, they might increase the number of beta cells for transplant operations. This type of cellular reprogramming involved here is fascinating. I remember when few believed de-differentiation from adult cells to pluripotent stem cells was possible with out the help of egg cytoplasm. iPS cells proved that wrong. This fate-jumping reprogramming without intervening de-differentiation is even more astonishing.


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Shanghai stem cell conference promises more to come

Shanghai crab is a delicacy available for only a short time each year, and the 20-million-strong href="http://query.nytimes.com/gst/fullpage.html?res=9A0DE2D91F3BF937A2575AC0A960948260&sec=travel&spon=&pagewanted=1" > residents of Shanghai devote themselves to its consumption. It was auspicious that the tasty crabs were still available during the first Shanghai International Symposium on Stem Cell Research, attended by around 500 scientists, hundreds of Chinese researchers and close to 100 foreigners. (NOTE: I wrote this on November 10th, but wasn't able to post until today.)

To put that in perspective, the last meeting of International Society for Stem Cell Research, the biggest annual stem cell conference, drew just over 1,900 attendees in June this past year.

China’s government and academies are pouring resources into stem cell research, and Chinese-born researchers trained in the United States are proving a huge asset. Some are returning to China to head up labs in that country; others are remaining in the US but forming collaborations with researchers in China.

Continue reading "Shanghai stem cell conference promises more to come" »

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Arrival in Cairns, Australia

The people in the airport keep calling me “love”. Telltale cardboard tubes show who on the airport shuttle bus is headed to the annual meeting of the International Society for Stem Cell Research in Cairns, Australia. I start chatting with a young blonde professor from Sweden who is turning embryonic stem cells into neurons, and she laughs as she tells me she sometimes hates human cells. Mice ES can generate neurons in maybe 10 days, but human ones take 20 or even 50.
Just before the bus heads off, another researcher boards. He was born in Iran but he moved to Sweden in his youth, and the two scientists talk across me in Scandanavian syllables. He's a former surgeon happens to be working in lower back pain caused by tissue degeneration. He’s been trying to implant mouse cells into damaged rabbit spines, but he’s frustrated because bone growth in rabbits mean the cells won’t take hold. He’s soon to move to a new lab where he can try the same thing in pigs; he’s excited to get started. “Pigs,” he keeps saying, referring to the innards of the spinal cord. “They look just humans.”