Stem cells have become a favoured miracle treatment among the rich and famous, with Kim Kardashian reportedly a fan of stem cell facials and Cristiano Ronaldo turning to stem cell injections after a hamstring injury.
The latest to extol their benefits is the Monty Python actor John Cleese, who suggests that stem cells could hold the secret to eternal youth – or, at least, buy him “a few extra years”.
In an interview with Saga magazine, the 84-year-old revealed that for the past two decades he has been paying a private Swiss clinic £17,000 every 12 to 18 months for stem cell therapy that he credits for looking “not bad” for his age.
So is Cleese making a sound investment? Stem cells have remarkable medical potential. They are the body’s master cells that, in the embryo, go on to produce every cell type in the body. Even in adulthood our body retains reserves of less versatile stem cells that mobilise to repair injuries and continually regenerate skin and other tissues.
Stem cell transplants have long been used in treating leukaemia and there are a wealth of groundbreaking trials using stem cells to treat genetic skin disorders, Parkinson’s disease and epilepsy.
However, there are also private clinics making far-reaching claims that fall into a regulatory “grey zone” because these therapies use patients’ own cells rather than drugs that would need to be licensed.
“There’s not a single clinical trial indicating that these treatments are safe or effective,” said Prof Darius Widera, a stem cell biologist at the University of Reading. “All of these clinics are exploiting a regulatory loophole.”
It is not clear what type of therapy Cleese has been receiving, although he described something like a biological MOT, saying: “These cells travel around the body and when they discover a place that needs repair, they’ll change into the cells that you want for repair, so they might become cartilage cells or liver cells.”
Typically, clinics extract stem cells from fat tissue, multiply them in the lab and re-infuse them. Widera is blunt in his verdict on the likelihood of stem cells achieving the intended effects: “No, they won’t do that.”
Adult stem cells are already somewhat specialised and so won’t readily turn into liver cells, for instance. And the body becomes less efficient at recruiting stem cells as we get older, whether they are injected or not.
“If you transplant a stem cell into an old environment it won’t work as well,” said Prof Ilaria Bellantuono, co-director of the Healthy Lifespan Institute at the University of Sheffield. “They will be influenced by their old environment.”
There are also concerns about the safety of such therapies. Several patients lost their sight after receiving stem-cell treatment for degenerative eye conditions at an unregulated clinic in Florida. Other complications from unregulated treatments include life-threatening infections, tumours, heart attacks or even death.
Prof Paul Knoepfler, a stem cell expert at the University of California, Davis, said: “I love John Cleese, but I worry that his stem cell anti-ageing attempts could do more harm than good.
“First, the stem cells he regularly gets could pose health risks to him. It’s not clear that any particular kind of stem cells are safe or effective unless they’ve undergone careful clinical trials. Also, the claims he makes about anti-ageing are unproven.
“The second thing is that over-exuberant statements made by celebrities about what stem cells might have done for them can encourage everyday people to follow their lead with both health and financial risks.”
Cleese says he has been receiving stem cell therapy for 20 years, which would make him an early adopter but now leaves him behind the curve. In the last few years, the field of longevity research has shifted away from stem cells as scientists and Silicon Valley billionaires have turned their focus to the potential of various molecules to “rewind the clock” on cells throughout the body. There is compelling evidence that such life-extending treatments work in animals at least, with one team reporting the oldest living lab rat last year.
“Small molecules in the field is really the future,” said Prof Evelyne Bischof, who carries out research into longevity at Jiaotong School of Medicine in Shanghai.
It remains to be seen whether longevity drugs have similarly impressive rejuvenating effects in humans as in rodents. But unlike stem cell infusions, which require bespoke preparations that are administered by medical professionals, such anti-ageing pills could become mainstream rather than remaining the preserve of Hollywood stars.
“It will be small molecule drugs that will make the real change,” said Bischof. “Not just for the patient, but also for accessibility.”