Celebrities and athletes including Chris Hemsworth, John Cleese, and Tom Brady have all endorsed expensive, unregulated stem cell treatments for a number of conditions. But, experts say the evidence behind these costly treatments is lacking, and they may pose a risk to your health.
Since their discovery in the 1960s, stem cells have captivated our curiosity. Unlike other cells in the body, stem cells are changeable — they can self-renew and they can differentiate into different, specialized cell types, raising the possibility that we could one day regenerate damaged tissue and organs. Stem cell therapies have led to the development of bone marrow transplants for cancer patients. But beyond that, stem cells haven’t fully lived up to the hype.
Despite a lack of evidence, an unregulated $2 billion industry has flourished, with clinics in the U.S. and abroad offering expensive, unproven, and risky treatments for every disease and condition under the sun. Between 2009 and 2017, more than 680 stem cell clinics popped up in the U.S. alone.
Many stem cell clinics offer treatments for Alzheimer’s disease without any evidence that they work. Australian actor Chris Hemsworth, who has two copies of the ApoE4 risk gene, has featured some of these companies on his Instagram.
“An endorsement by a celebrity like this makes it easier for clinics to market unproven stem cell therapies, heightening the potential to exploit desperate and scared individuals.” Timothy Caulfield, a professor of law and public health at the University of Alberta, told Being Patient. “There is no good clinical evidence to suggest that stem cells will work in this space.”
The science of stem cells
Every multicellular organism begins as one cell that divides over and over again.
Some daughter cells are pluripotent stem cells, meaning they can become any other cell type in the body, like muscle or nerve cells. Other stem cells are more specialized; they’re called multipotent stem cells and can only become one of a few options. For example, mesenchymal stem cells, which are multipotent, can only turn into cartilage, fat, or muscle cells.
There are two different ways a stem cell could potentially treat disease, Dr. Arnold Kriegstein, a neurologist at UCSF and a leading expert on stem cells, told Being Patient.
The first approach is replacing cells that are damaged or die off. “In Parkinson’s disease, there’s a very specific nerve cell type, a dopamine-producing nerve cell that is selectively vulnerable and dies early on,” he said. “The idea of cell replacement therapy is to make those dopamine neurons out of pluripotent stem cells and then graft them into the patient’s brain.”
Some scientists use another approach, Kriegstein explained. They take “advantage of factors that are secreted by the stem cells, and that may have effects on the immune system.” The factors are types of proteins called trophic and growth factors that help cells grow and regenerate, as well as cytokines that regulate inflammation.
As of right now, there is no evidence that stem cells can treat any neurodegenerative disease, even if some clinics are making dubious claims that they can.
Why is it legal to sell stem cell therapies?
Many clinics focus on mesenchymal stem cells, which they harvest from a patient’s fat and reinfuse into the body. This is called an autologous treatment because the stem cells come from the patient, eliminating the risk of the body rejecting a treatment.
A loophole in the Food and Drug Administration’s regulation of these therapies allows companies to offer autologous treatments without proving they’re safe and effective.
“They’re not considered a real drug [by the FDA] unless they’ve been manipulated in a certain way prior to beginning being given back to the patient,” Kriegstein said. “That has allowed a lot of these bogus clinics to take fat cells or mesenchymal cells, and claim that they can treat a large number of diseases.”
Many stem cell clinics, including the one featured in Hemsworth’s recent Instagram, make vague health claims about mesenchymal stem cells.
“The idea that these mesenchymal cells can treat a disease is based on a large body of largely unproven or bogus publications,” Kriegstein said.
Although some studies show that these cells release many cytokines and trophic factors in a Petri dish, “that doesn’t mean that they’ll have a therapeutic effect when you put them into a patient with the disease,” Kriegstein added. However, it allows the stem cell clinics to make vague claims about how the treatment will work.
The liver destroys mesenchymal stem cells soon after they’re infused into the body. Since they don’t survive very long, Kriegstein explained that they don’t have much of an effect since they don’t survive very long.
What are the risks of using stem cell clinics?
While mesenchymal stem cells might not cause much harm because the liver quickly destroys them, treatments can cost thousands of dollars. However, there are additional health risks with other types of stem cell therapies. “These cells can really cause all kinds of mischief,” said Kriegstein.
Some states, like Utah, have more permissive laws, allowing clinics to offer stem cells collected from other patients. The Utah Cord Bank sells stem cells taken from amniotic fluid. Ten million cells are frozen in small vials and sent to clinics, where they can be injected into patients.
Journalists working for ProPublica sent these vials to two independent laboratories for analysis. More than half of the cells in the vials were dead, and there were only 600,000 live cells instead of the 10 million claimed to be in the vial. Experts doubted they were amniotic stem cells since they don’t easily survive freezing and thawing.
Some types of stem cell therapy can cause lifelong harm. Three patients in Florida went blind because of a stem cell therapy they used to try and treat a degenerative problem with their vision.
In other cases, patients received stem cells via lumbar puncture to treat a brain disease but ended up forming tumors instead, which in some cases were inoperable. There are also frequent reports of people acquiring deadly bacterial infections from stem cell clinics, developing lifelong disabilities, or even dying.
Are stem cells promising for neurodegenerative disease?
Stem cells for dementia and neurodegenerative disease are still in the very early stages of clinical trials.
Scientists worldwide are testing whether they can treat Parkinson’s by making new dopamine-producing neurons from stem cells to replace the ones lost during the disease.
Skin2Neuron developed neuronal stem cells by reprogramming hair follicles. In a small veterinary trial of canine dementia, the newly formed brain cells were injected into the brain and successfully treated some dogs’ symptoms. The company may test this approach in humans with neurodegenerative diseases in the future.
Longeveron’s Lomecel-B uses mesenchymal stem cells from the bone marrow of healthy young adults. The cells are infused intravenously into patients, which the company hopes will work to reduce inflammation and help the brain repair itself.
The company completed an early Phase 2 trial in 2023 for Alzheimer’s disease but has not published the full results or announced whether they’ll run an additional study. Longeveron was sued by investors in 2021 for making false and potentially misleading statements about clinical trials the company ran testing the Lomecel-B for treating age-related frailty. The company settled with investors outside of court.
There are also a few other early-stage trials testing therapies for Alzheimer’s, but it may be years before we know if any of them work.
“There are very few proven therapies using stem cells,” Kriegstein said. “For the vast majority of diseases, including those really terrible neurological diseases like ALS, Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, and MS, there are no proven stem cell therapies.”
