Medical regulators have been warning that the downside of unproven stem cell treatments isn’t merely that they won’t work, but that they can be life-threatening.
A team of Canadian physicians has just reported an especially gruesome example of what can go wrong when desperate patients chase after last-ditch cures in what’s known as stem cell tourism. Their subject is a 38-year-old Newfoundland man who became a paraplegic after a trampoline accident at the age of 20 injured his spinal column.
Six years later, he traveled to Portugal for a stem cell treatment. Doctors there transplanted olfactory mucosal cells drawn from his upper nasal passages into the site of his spinal injury. He never got better, but years later started getting worse.
We want to make sure the same thing doesn’t happen to anyone else.
Doctors at Memorial University of Newfoundland discovered that the olfactory cells had never differentiated into neuronal cells, as the Portuguese clinic apparently expected, but kept growing on their own, producing a tumor of nasal cells that’s now too large to be surgically removed.
“This was a young man with a life-altering injury and would have tried anything for a chance to walk again,” Nanette Hache, one of the physicians, told me. The Portuguese operation cost $50,000, plus possibly that much more for travel, accommodations and postoperative support. The doctors published (with the patient’s consent) “because we want to make sure the same thing doesn’t happen to anyone else.”
As many as three other similar cases have been identified in scientific journal reports, according to Leigh Turner, a bioethicist at the University of Minnesota who has been tracking the proliferation of unproven stem cell treatments for several years. All went to the same clinic in Portugal, which has claimed to have treated more than 120 patients.
Last year, Berlin-based researchers compiled a list of 35 adverse incidents resulting from unproven stem cell treatments performed mostly in China, Thailand, Argentina, Mexico, Costa Rica, Egypt, Dominican Republic and Russia. Some were done in Germany, Australia and the U.S. as well. The negative outcomes included tumors, blindness, brain hemorrhages, strokes, pneumonia and death.
The researchers observed, however, that their list was almost certainly incomplete, in part because the true number of treatments is unknown. The evidence at hand, however, indicated “substantial patient exploitation using the ‘power of hope.’”
Credulous media reports add to the dangers. Consider the recently reported experience of Caroline Wyatt, a prominent BBC journalist who at the age of 49 underwent a stem cell treatment for multiple sclerosis in Mexico in 2017, lured there by reports (on the BBC) of “near miraculous results.” She raised $84,000 from friends and family, because Britain’s health system wouldn’t cover the procedure. A month after her treatment, she told a BBC news program that she was “feeling better than I have done in a long time.”
Clinics offering stem cell-based nostrums in the U.S. typically use cells derived from fat, removed from patients by liposuction, purportedly treated to concentrate the stem cells, which are then injected into a customer’s body.
The use of olfactory cells appears to be a relatively novel application for spinal cord injuries. The process isn’t utterly devoid of scientific logic. Olfactory mucosal cells have neuronal features and are known to regenerate themselves, which suggests they could fulfill the function of spinal cells, which don’t regenerate, at least in theory.
“It’s not entirely ‘out there,’” Hache says. “Legitimate research is being done, but as for the next leg, transplanting them in patients — we’re not there yet.”
One problem made evident from the Newfoundland case and others is that the tumors caused by the transplants may not develop for years. The Portuguese clinic, which reported on the experiences of 20 patients in 2010, followed up on the patients only for an average of about two years and none for more than four.
The Newfoundland patient’s tumor, however, didn’t make its presence known for more than seven years after his transplant, and then only because his condition was worsening as the tumor grew.
The lesson, Turner says, is that “if you put the wrong kind of cells in the wrong place bad things can happen, even if symptoms don’t manifest right away.”