In a study slated to launch later this year, scientists hope to use stem cells to revive people who have been declared brain dead—a controversial effort that has drawn skepticism and sparked ethical concerns from experts, Kate Sheridan writes for STAT News.
A radical plan
According to Sheridan, the planned trial is a relaunch of a study in India that was shut down last year before it launched because it never garnered approval from the country's Drug Controller General. Bioquark, the Philadelphia-based biotechnology firm that is backing the research, is currently finalizing locations for the new trial in Latin America.
The overarching goal of the trial, Sheridan writes, is to resuscitate the brain by growing new neurons and spurring them to connect to each other. And if the trial reflects the protocol of the India one, it will involve 20 legally brain-dead subjects who would undergo three stages of treatment:
- Scientists first will inject stem cells culled from the subject's fat or blood into the spinal cord;
- Scientists will then inject a peptide formula into the spinal cord with the "purported" aim of helping foster new neuron growth; and
- Lastly, the subjects will receive nerve stimulation and transcranial laser therapy over 15 days, designed to spur connections between neurons.
Researchers would assess the progress of the treatment by examining the subjects' reaction, if any, and electroencephalography scans.
According to Ira Pastor, CEO of Bioquark, the multifaceted approach is a key aspect of the trial. "It's our contention that there's no single magic bullet for this, so to start with a single magic bullet makes no sense," he said. "Hence why we have to take a different approach."
Lingering questions prompt ethical, scientific concerns
But the effort, Sheridan writes, "is fraught with questions." For instance, she asks how researchers will file the appropriate paperwork when the subjects are legally deceased; what functional skills, if any, would individuals have if successfully resuscitated; and whether the entire enterprise extends a false hope to the family and friends of the subjects.
Moreover, the proposal has drawn backlash from medical experts, Sheridan writes. For example, in a 2016 editorial, physician Ariane Lewis and bioethicist Arthur Caplan wrote that the approach "borders on quackery," lacked any scientific foundation, and gave the families of the subjects "a cruel, false hope for recovery."
Little research, and medical skepticism
According to Sheridan, while some research has been conducted on each individual prong of the overall approach, there's "no real template" for whether all the approaches together will be effective.
For instance, she cites research linking stem cell injections to the brain or spinal cord with positive results among children with brain injuries, as well as a small study showing improved mobility among stroke victims who received a stem cell injection to the brain.
Meanwhile, research on transcranial laser devices has produced mixed results. While the approach has been linked to neuron growth in trials with animals, one high-profile human trial was stopped after it showed no improvements among people who had experienced a stroke.
For electrical stimulation of the median nerve, which extends from the spine down the arms and fingers, most of the research has been case studies, Sheridan writes. Ed Cooper, an orthopedic surgeon, teamed up with neurosurgeons to test the approach with several coma patients, some of whom made a "good recovery" despite initially earning very low scores on the Glasgow Coma Score. But Cooper argued that the technique would not work on brain-dead patients because it requires a functional brain stem.
Pastor agreed, but he contended that his multifaceted approach could work because in brain-dead patients, there is "a small nest of cells" that remains functional.
Another complication, according to Sheridan, is the lack of a standard measure for brain death. Without such a measure, it could be difficult to ascertain whether any potential recovery resulted from the new treatment. Bioquark intends to defer to physicians in the trial's host country on whether the subjects meet the local standard for brain death, Pastor said.
Separately, Charles Cox, a pediatric surgeon who has researched the sort of stem cells that are going to be used in the trial, said while Bioquark's overall approach is "not the absolute craziest thing I've ever heard, … I think the probability of that working is next to zero."
Cox explained that some research suggests cells from a certain part of the brain—the subventricular zone—can grow in a culture even after an individual has been declared dead. But the trial's goal to cultivate new neurons or connections via stems cells remains unlikely because neurons would have difficulty surviving given the lack of blood flow to the brain in brain-dead patients. "I think (someone reviving) would technically be a miracle," he said. "I think the pope would technically call that a miracle."
Pastor, for his part, remains optimistic about the project. "I give us a pretty good chance," he said. "I just think it's a matter of putting it all together and getting the right people and the right minds on it" (Sheridan, STAT News, 6/1; Mole, Ars Technica, 6/1).
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