World Stem Cell Summit: The environment stem cells find themselves in after transplant really matters

On Friday’s closing day of the 2014 World Stem Cell Summit a panel of three researchers working on neurodegenerative diseases drove home the importance of paying attention to the environment that surrounds stem cells after transplant.

world-stem-cells-summit-2014

CIRM grantee Evan Snyder from the Sanford-Burnham Institute noted that most of the neurologic diseases people are looking at are conditions associated with aging and the cellular makeup of the brain changes as we get older, adding that most of the diseases result from chronic states that have existed over many years. He contrasted this against mouse models of the disease, which usually involve artificially recreating the disease and treating shortly after the injury happens.

“In stem cell therapies there is a dialogue between the transplanted cells and the recipient. The host influences the fate of the stem cells.”

He noted that the patients we will be treating have generally had long-term degeneration and asked if we might be able to develop drugs that effect the environment where the stem cells will be placed so that it mimics more closely the environment found in the animal model in the acute phase, that is right after injury.

One aspect of the environment in the brain in most patients with neurodegeneration is chronic inflammation. Another CIRM grantee on the panel, Jeanne Loring of the Scripps Research Institute, discussed a project her team hopes will take advantage of the inflammation that occurs in Alzheimer’s disease. They are loading nerve stem cells with an enzyme that can degrade the plaque that accumulates in nerves in the disease. Because stem cells home to inflammation, they hypothesize that the stem cells will be drawn to deliver their cargo to the nerves with the worst plaque.

The third panelist, Erzi Kokovay of the University of Texas Health Science Center in San Antonio, described the changes in the brain as we age in a bit more detail. She described infiltration of cells called microglia that researchers will need to take into account when they plan to transplant stem cells in the brain.

While on the surface this all may sound like another road block to getting to the stem cell cures we all want, the presentation actually made me optimistic that we are starting to learn enough about the field that we are more likely to get it right when we start to treat some of these devastating brain diseases.

Don Gibbons

At World Stem Cell Summit improvements in the precision with which we can edit our genes grabs spotlight

Just a day and a half into this year’s World Stem Cell Summit in San Antonio and there have been numerous highlights. But a pair of sessions on gene editing grabbed the attention of many of the scientists at the meeting. One of the renown leaders in the field, Harvard’s George Church wowed the scientists, but I fear the heavy dose of scientific detail may have overwhelmed many of the patient advocates that make the attendee mix at this meeting special.

George Church speaking recently [Credit: PopTech.org]

George Church speaking recently [Credit: PopTech.org]

In 2013, Church first published results using a new gene-editing tool he helped perfect called CRISPR, and almost immediately it became the most talked-about tool for advancing stem cell research. As powerful as stem cells may be by themselves, in many situations, they become even more powerful—especially if you use them to deliver a gene that corrects an error in a patient’s cells. Before 2013 we had a few ways to edit genes in living cells and all were modestly effective at making the desired change and relatively specific in making only a few unwanted changes, called “off target” edits.

In some uses, particularly when cells are being modified in the lab for specific and small targets, these other editing techniques are probably OK. This is what several CIRM-funded teams (links) are doing with diseases like sickle cell anemia and HIV, where you can target blood-forming stem cells and even giving a small percentage the proper gene edit may be sufficient to cure the disease. But with something like muscular dystrophy where the gene editing would be required throughout the body and have to be done in the patient not in the lab, you need to improve the efficiency and precision.

CRISPR/Cas9 [Credit: University of California, San Francisco]

CRISPR/Cas9 [Credit: University of California, San Francisco]

After that first publication CRISPR was viewed as a home run in efficiency, taking the number of cells with the gene correction from a few percent to 50 percent or more. But it still had off-target effects. Yet only a year after the technology was introduced, a few teams developed so-called “next generation” CRISPR that comes close to perfect precision, causing an unintended edit in just one in a billion cells, by Church’s estimate.

I have never seen the full name of CRISPR spelled out in a scientific presentation, and after a visit to Wikipedia I know why. Here it is: Clustered Regularly Interspersed Short Palindromic Repeats. Basically, Church took advantage of something that occurs naturally in many bacteria. Just as we are susceptible to viruses, bacteria have their version known as phages. When those parasites integrate their DNA into the bacteria’s genes, part of the bacterial DNA forms CRISPRs that can partner with a protein called Cas to cut the phage DNA and keep the phage from hurting the host bacteria.

In a research setting, creating that “nick” in the DNA is the first step in harnessing CRISPR to insert a desired gene. So, that extreme precision in finding spots on our DNA where we want to create an opening for inserting a new gene became this valuable research tool. It can create a nick as precise as a single nucleotide base, the building blocks of our DNA.

Church and two additional speakers gave detailed descriptions about how the technology has improved and how it is being used to model disease today and is expected to be used to treat disease in the near future. An exciting future is in store.

Don Gibbons

Truth or Consequences: how to spot a liar and what to do once you catch them

Nothing undermines the credibility of science and scientists more than the retraction a high profile paper. Earlier this year there was a prime example of that when researchers at one of Japan’s most prestigious research institutions, the Riken Center for Developmental Biology in Kobe, had to retract a study that had gathered worldwide attention. The study, about a new method for creating embryonic-like stem cells called stimulus triggered acquisition of pluripotency or STAP, was discredited after it was discovered that the lead author had falsified data.

Publication retractions have increased dramatically in recent years [Credit: PMRetract]

Publication retractions have increased dramatically in recent years [Credit: PMRetract]

The STAP incident drew international coverage and condemnation and raised the question, how common is this and what can be done to combat it? A panel discussion at the World Stem Cell Summit in San Antonio, Texas entitled “Reproducibility and rigor in research: What have we learned from the STAP debacle” tackled the subject head on.

Ivan Oransky, medical journalist and the co-founder of the website Retraction Watch posed the question “Does stem cell research have a retraction problem?” He says:

“The answer to my question is yes. But so does everyone else. All of science has a retraction problem, not just stem cells.”

Oransky says the number of retractions has doubled from 2001 to 2010. One author has retracted 183 times – the record so far – but to break into the top 5 you need to have at least 50 retractions. These come from all over the world from the US to Germany and Japan and most recently Azerbaijan.

Oransky says part of the problem is the system itself. Getting your research results published is critical to advancing a career in science and those kinds of pressures force people to cut corners, take risks or even just falsify data and manipulate images in order to get a paper into a high profile journal. In most cases, journals charge a fee of several hundred to thousands of dollars to publish studies, so they have no incentive to dig too deeply into findings looking for flaws, as it might undermine their own business model.

“Some authors, more than 100, have been caught reviewing their own papers. When the journal they were submitting their paper to asked for the names of recommended reviewers they would submit the names of people who are legitimate reviewers in the field but instead of giving real email addresses they would give fake email addresses, ones they controlled so they could submit their own reviews under someone else’s name.”

What gave them away is that all the potential “reviewers” didn’t first reply and say “yes, I’ll review”, instead they responded by sending back a full review of the paper, raising suspicions and ultimately to detection.

Graham Parker, a researcher at Wayne State University School of Medicine and the editor of Stem Cell and Development says spotting the problem is not always easy:

“As an editor I regard scientific misconduct as fabrication, falsification or plagiarism of data but there are lots of other areas where it’s not always so clear – there are often shades of gray”

He says researchers may make an honest mistake, or include duplicative images and in those cases should be allowed to fix the problems without any stigma attached. But when serious cases of falsification of data are uncovered they can have a big impact by retarding scientific progress and sapping public confidence in the field as a whole.

Jeanne Loring, a stem cell scientist at The Scripps Research Institute and a recipient of funding from CIRM, says the STAP incident was actually a sign of progress in this area. Ten years ago when a Korean researcher named Hwang Woo-Suk claimed to have cloned human embryos it took more than a year before he was found to have falsified the data. But in the STAP case it took a little over a week for other researchers to start raising red flags:

“One of the real heroes in this story is Paul Knoepfler (a CIRM-funded researcher at UC Davis) who takes on difficult issues in his blog. It took Paul just 8 days to post a request for people to crowdsource this study, asking people who were trying to replicate the findings to report their results – and they did, showing they failed over and over again”

Parker said it’s getting easier for editors and others in the field to double check data in studies. For example new software programs allow him to quickly check submitted manuscripts for plagiarism. And he says there is a growing number of people who enjoy looking for problems.

“Nowadays it’s so easy for people to dig very deeply into papers and check up on every aspect of it, from the content to the methodology to the images they use and whether those images were in any way manipulated to create a false impression. Once they find a problem with one paper they’ll dig back through papers in that scientist’s past to see if they can find other problems dating back years that were never found at the time.”

He says that in most cases researchers caught falsifying data or deliberately misleading journals faced few consequences:

“Often the consequences of misconduct are very mild, the equivalent of a slap on the wrist, which does not discourage others from trying to do the same.”

Each panel member says that tougher penalties are needed. For example, in extreme cases a threat of criminal action could be warranted, if the falsified research could lead to serious consequences for patients.

But the panel ended on an encouraging note. Oransky says, for example, that medical journals are now paying more attention and imposing stricter rules and he says there’s even scientific evidence that “doing the right thing might pay off.”

“One study recently showed that if you made an honest error and corrected it publicly not only does the stigma of retraction not apply to you, you don’t get a decrease in your citations—you actually get an increase. So we’d like to think that doing the right thing is a good thing and might actually be a positive thing.”

Taking Promising Therapies out of the Lab and into People: Tips from Experts at the World Stem Cell Summit on How to Succeed

Having a great idea for a stem cell therapy is the easy part. Getting it to work in the lab is tougher. But sometimes the toughest part of all is getting it out of the lab and into clinical trials in patients. That’s natural and sensible, after all we need to make sure that something seems safe before even trying it in people. But how do you overcome all the challenges you face along the way? That was the topic of one of the panel discussions at the World Stem Cell Summit in San Antonio, Texas.

Rick Blume is the Managing Director at Excel Venture Management, and someone with decades of experience in investing in healthcare companies. He says researchers face numerous hurdles in trying to move even the most promising therapies through the approval and regulatory process, only some of which are medical. Blume says:

“Great ideas can become great companies. And good Venture Capitalists (VCs) can help with that process, but the researchers have to overcome technical, funding and logistical hurdles before VCs are usually ready to move in and help.”

Of course that’s where agencies and organizations like CIRM come in. We help fund the early stage research, helping researchers overcome those hurdles and getting promising therapies to a point where VCs and other large investors are willing to step in.

Left to right: Geoff Crouse CEO of Cord Blood Registry, C. Randal Mills, President and CEO of CIRM, Rick Blume of Excel Venture Management and Anthony Atala of Wake Forest University Medical Center

Left to right: Geoff Crouse CEO of Cord Blood Registry, C. Randal Mills, President and CEO of CIRM, Rick Blume of Excel Venture Management and Anthony Atala of Wake Forest University Medical Center

Geoff Crouse, the CEO of the Cord Blood Registry, says researchers need to be increasingly imaginative when looking for funding these days.

“While Federal funding for this kind of research is drying up, there are alternatives such as CIRM and philanthropic investors who are not just seeking to make active investments but are also trying to change the world, so they offer alternatives to more traditional sources of funding. You have to look broadly at your funding opportunities and see what you want to do.”

C. Randal Mills, the President and CEO of CIRM said too many people get caught up looking at the number of challenges that any project faces when it starts out:

“The single most important thing that you need to do is to show that the treatment works in people with unmet medical needs, that it is safe. If you can do that, all the other problems, the cost of the therapy, how to market it, how to get reimbursed for it, those will all be resolved in time. But first you have to make it work, then you can make it work better and more efficiently.”

The panel all agreed that one of the areas that needs attention is the approval and regulatory process saying the Food and Drug Administration (FDA) the regulatory body governing this field, needs to adjust its basic “one size fits all” paradigm.”

Mills says the FDA is in a difficult position:

“Everyone wants three things; they want fast drugs, they want cheap drugs and they want perfect drugs. The problem is you can’t have all three. You can have two but not all three and that puts the FDA into an almost impossible position because if therapies aren’t approved quickly they are criticized but if they are approved and later show problems then the FDA is criticized again.”

Often the easiest way to get a traditional drug therapy approved for use is to ask for a “humanitarian exemption”, particularly for an orphan disease that has a relatively small number of people suffering from it and no alternative therapies. But when it comes to more complex products knows as biologics, which includes stem cell therapies, this humanitarian exemption does not exist making approval much harder to obtain, slowing down the field.

Mills says other countries, such as Japan, have made adjustments to the way they regulate new therapies such as stem cells and he hopes the FDA will learn from that and make similar modifications to the way they see these therapies.

All three panelists were optimistic that the field is making good progress, and will continue to advance. Good news for the many patient advocates attending the World Stem Cell Summit who are waiting for treatments for themselves or loved ones.

At World Stem Cell Summit: Why results in trials repairing hearts are so uneven

Just as no two people are the same, neither are the cells in their bone marrow, the most common source of stem cells in clinical trials trying to repair damage after a heart attack. Doris Taylor of the Texas Heart Institute in Houston, which is just a couple hours drive from the site of this year’s World Stem Cell Summit in San Antonio, gave a key note address this morning that offered some good reasons for the variable and often disappointing results in those trials, as well as some ways to improve on those results.

THI's Dr. Doris Taylor

THI’s Dr. Doris Taylor

The cells given in a transplant derived from the patient’s own bone marrow contain just a few percent stem cells and a mix of adult cells, but for both the stem and adult cells the mix is highly variable. Taylor said that in essence we are giving each patient a different drug. She discussed a series of early clinical trials in which cell samples from each patient were banked at the National Heart and Lung and Blood Institute. There they could do genetic and other analysis on the cells and compare that data with how each individual patient faired.

In looking at the few patients in each trial that did better on any one of three measures of improved heart function, they were indeed able to find certain markers that predicted better outcome. In particular they looked at “triple responders,” those who improved in all three measures of heart function. They found there were both certain types of adult cells and certain types of stem cells that seemed to result in improved heart health.

They also found that two of the strongest predictors were gender and age. Women generally develop degenerative diseases of aging like heart disease at an older age than men and since many consider aging to be a failure of our adult stem cells, it would make sense that women have healthier stem cells.

Taylor went on to discuss ways to use this knowledge to improve therapy outcomes. One way would be to select for the more potent cells identified in the NHLBI analysis. She mentioned a couple trials that did show better outcomes using cells derived from heart tissue. One of those is work that CIRM funds at Cedars-Sinai in Los Angeles.

Another option is replace the whole heart and she closed with a review of what is probably her best-known work, trying to just that. In rats and pigs, she has taken donor hearts and used soap-like solutions to wash away the living cells so that all that is left behind are the proteins and sugars that make of the matrix between cells. She then repopulates the scaffolds that still have the outlines of the chambers of the heart and the blood vessels that feed them, with cells from the recipient animal. She has achieved partially functional organs but not fully functional ones. She—along with other teams around the world—is working on the remaining hurdles to get a heart suitable for transplant.

Don Gibbons