With stem cells slowly making their way into common medical practice, the answer to hundreds of diseases and disabilities might be contained in one swift injection.
In his lab, David Schaffer, director of the Berkeley Stem Cell Center on campus, and others are currently trying to turn the cells from unused embryos into the specific neurons lost to Parkinson’s disease, a brain disorder that causes tremors and difficulty in movement and coordination. Current treatment options for Parkinson’s are limited to medication, brain surgery and physical therapy, but these only treat the symptoms of the disease.
“If you had the option of having to take prescription medicines for the rest of your life versus a single injection cure … You can see why the field’s so enthusiastic,” Schaffer said.
Others, citing moral and religious convictions, have had reservations about the development of such therapies.
Still, in 2004, California passed Proposition 71, officially deeming stem cell research a constitutional right. A Center of Excellence grant allocated $20 million to UC Berkeley to grow the field, with the money ultimately used for the construction of the Li Ka Shing Center, where the campus Stem Cell Center is housed.
The Scientific Method
The biggest question all researchers within the stem cell community strive to answer is how a stem cell can be controlled — or in Schaffer’s case, how embryonic stem cells can be converted, or “differentiated” into dopaminergic neurons, those chronically lacking in the brain of Parkinson’s patients.
The researchers, including postdoctoral fellows Badri Ananthanarayanan and Tandis Vazin, currently grapple with the challenge of transplanting the neurons from the petri dish, in which they are grown, to the site of injury, all without damaging the cells.
“There’s a 95 percent chance of those cells dying (once you inject them into the brain),” Ananthanarayanan, who works in Kumar Laboratory, headed by bioengineering professor Sanjay Kumar, said. “If you generate these cells in a dish, scrape the cells off the dish, collect them and inject them, a lot of them die in the process because they go through a lot of stress.”
Ananthanarayanan and his colleagues are specifically experimenting on rats, injecting dopaminergic neurons into their brains and subsequently observing whether the neurons function properly and survive. Working with a total of approximately 12 rats, the researchers hope to increase their sample size to about 30 rats once they garner positive results to iteratively test their methods on a larger scale.
Ananthanarayanan said preliminary data is hopeful, and the next step is work on bigger animals, such as monkeys. Vazin said she predicts the team’s work with the rats could be finalized within a year.
But Schaffer predicts it will still take five years before his lab can start clinical trials to test stem cell-based cures for Parkinson’s, as there is much room for error.
The cells must undergo a crucial maturation before they can fully function. This delicate process is achieved by adding genes to stem cells to artificially age them and make them behave as mature cells, explained Lorenz Studer, director of the Center for Stem Cell Biology of the Sloan-Kettering Institute in New York.
In addition to these steps, Schaffer and his team must satisfy FDA guidelines to minimize the risk of harm and test the product’s efficiency, a process that normally takes many years to complete.
“You get stuck in the day-to-day grind, like, ‘Is my experiment working?’” said Dawn Spelke, a bioengineering graduate student who works in Schaffer’s lab but is not working on the study of Parkinson’s. “It’s exciting because it’s starting to be commercialized. We’re seeing that stem cell therapies can work.”
According to Vazin, the team’s goal is working to further understand the intricacies of the differentiation process so they can predict uniformly positive results with every trial. Successful trials would entail that the differentiated neurons do not multiply into a brain tumor or morph into a different cell entirely.
“I think there can be a public lack of understanding of how long therapies take,” Spelke said. “There are complex treatments to complex diseases.”
A philosophical debate, a medical advancement
According to researchers, this lack of understanding on the subject has also manifested as a philosophical debate among people who believe stem cell research to be immoral or even illegal.
Though federal funding for stem cell research has been consistent, public opposition, which peaked in the mid 2000s, creates precarious circumstances for researchers working to push forward the medical benefits of stem cell research.
“At any point in the future, if the political winds shift in the other direction, the field could become very restricted again,” Schaffer said.
From Studer’s perspective, most of today’s opposition comes from “fundamentalists” who equate the life of an embryo to the life of the baby.
Many researchers reason that because surplus egg cells, harvested in large quantities from the woman for in vitro fertilization, are usually thrown away after the fertilization process, the remaining egg cells could be used to conduct embryonic stem cell research.
“It is an opinion of religion and morality,” Studer said. “Embryos have moral value, but it’s a stretch to give more moral value to a fertilized egg than to an actual baby — an actual human.”
According to Lily Mirels, the program manager of the Berkeley Stem Cell Center, new strides in medicine have introduced alternative options for stem cell research that have begun to assuage much of the opposition surrounding the technology. Using induced pluripotent cells, stem cells not deriving from embryos, the same methods of experimentation can be executed to garner the same results.
Since the discovery of these cells in 2006, coupled with the recent medical breakthroughs emerging from institutions like the Berkeley Stem Cell Center, some of the controversy has begun to fizzle out.
According to a a 2012 report by the National Science Foundation, the stigma surrounding stem cell research has notably dwindled in recent years, with 62 percent of Americans favoring embryonic stem cell research in 2010 and even more favoring studies with stem cells derived from alternative areas such as bone marrow and the brain.
Schaffer and his team, who have yet to encounter hostility to their stem cell research, are now focused on moving forward with their research and pushing the boundaries of biomedical capabilities.
“We believe it is the future of all medicine,” Spelke said.