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.
Ruth McKernan, who heads the regenerative medicine unit at Pfizer, thought interest in cells as therapy had increased. She also noted this year’s talks displayed a greater range of topics, with more emphasis on mechanisms. These feelings were echoed by Mahendra Rao, vice president of research in stem cells and regenerative medicine at Life Technologies who said he was glad for the developmental biology theme and that not all the talks were restricted to human systems.
Epigenetics was the theme everyone named on the first day of the conference, but by the last day the theme had grown both broader and more specific: identifying and overcoming the barriers to reprogramming. And reprogramming did not necessarily mean inducing a cell all the way to pluripotency; it could also mean pulling a cell into a fate it wouldn’t take assume in normal development.
“We need mechanisms to compare iPS cells, but we also need to remember that these cells are just reagents,” said Doug Melton of the Harvard Stem Cell Institute. “What’s going to be useful is what you’re going to do with them.”
In fact, in a long conversation I had with Allan Spradling of the Carnegie Institute he said he was still skeptical of cells differentiated in culture. In a culture system, only some of the cells “do anything”, he explained, “but in an embryo, every cell is doing what it’s supposed to be doing when it’s supposed to be doing it.” If scientists hope to get cell therapies to work, they’ll need to study the embryo and regenerating tissues more carefully. “No cell is going to do something it hasn’t evolved to do,” Spradling predicted. Researchers are going to need to know more about how tissues fix themselves naturally and then mimic the process, he said. A stem cell, after all, might not be a repair-competent cell.
Overall, though, Spradling thought the field had hit a good turning point. “I’m feeling more comfortable,” he told me. Spradling literally and figuratively dissected the stem-cell niche in fruit fly ovaries decades ago, establishing principles that now permeate the field. He said he had been more worried that the field was stuck just finding stem cells in various niches. Now, he said, researchers could start studying how they function and deducing general principles: “We’re seeing a lot of similarities.”
(BTW: there were several more conversations I’d like to report on, but I’m refraining if there was a question whether the conversation was off record, or if too much time elapsed between when I spoke with someone and when I could write down my notes.)