Stem cells are cells that can differentiate - or change - into other types of cell, opening the possibility of replacing damaged cells with healthy ones. Scientists have been looking into their use since the Sixties, most successfully so far in cases of cancers of the blood or bone marrow. More than 26,000 patients are treated with blood stem cells in Europe each year.
And since the Eighties, skin stem cells have been used to grow skin grafts for patients with life-threatening burns; most recently, a new stem cell-based treatment to repair damage to the cornea (the surface of the eye) after an injury like a chemical burn, has received conditional approval in Europe.
But their flexibility offers hope for lots of illnesses and conditions including heart disease, MS and macular degeneration - and clinical trials are progressing in all these areas. Chronic spinal cord injury is being researched with some promise, thanks to the Christopher & Dana Reeve Foundation, set up after actor Christopher Reeve was paralysed in a riding accident.
Crucially, for cases such as Schumacher, stem cells are also being explored for neurodegenerative diseases like Parkinson's and Alzheimer's - and traumatic brain injuries like the one he suffered in a skiing accident in December 2013.
Head injuries are difficult to treat as brain damage cannot be undone and each case is different. Asked for comment by The Daily Telegraph, the hospital responded that they could neither confirm nor deny the presence of Schumacher.
However, if he is under the care of Mr Menasché it is likely he will have had stem cells delivered by an IV to the area of the body where it is felt they could work best - whether that is his head or heart.
In a recent interview online, Mr Menasché explained that stem cell treatment for cardiac conditions - his particular area of expertise - is in its infancy. "Nobody really knows how stem cells are working," he said. "They do not permanently transplant into the myocardium [the muscular tissue of the heart] - after a couple of days or weeks, they just disappear.
"But you still may have a functional benefit as during their transient stay in the heart," he explains in the Future Tech podcast, "as the cells release molecules into the tissue. The hypothesis is that the repair comes from the heart itself, stimulated by these molecules."
Should the stem cells have been intended for Schumacher's brain injury, research suggests that the treatment has potential. A University of Plymouth study published in the journal Cell Reports in June found that neural stem cells could be used to "wake up" and produce new neurons (nerve cells) and surrounding glial cells in the brain.
The research is in its infancy, says lead author Dr Claudia Barros, from the Institute of Translational and Stratified Medicine at the University of Plymouth, who acknowledges there is still a long way to go until such findings can be translated into human treatments.
"We are working to expand our findings, to bring us closer to the day when human neural stem cells can be controlled and efficiently used to facilitate brain damage repair, or even prevent brain cancer growth that is fuelled by stemlike cells," she says.
A Chinese study published last month in the journal Frontiers in Cellular Neuroscience examined the current state of progress into the effects of stem cell therapy on traumatic brain injury. But the researchers from Zhejiang University, Hangzhou warned much more work was needed: "Although a large number of basic studies have confirmed that stem cells have good effect in the craniocerebral injury," they said, "the safety of stem cells, the route of injection, the time of injection and the specific mechanism are all factors that affect the clinical application of stem cells, and are the important research point in the future study."
In the UK, some applications of stem cell medicine are already available privately, although tightly controlled by the Human Tissue Authority - and not in the brain.
Simon Checkley, CEO at the Regenerative Clinic in Brighton, explains: "It is possible to get stem cells from sources outside your body, like the umbilical cord or Wharton's jelly [the vitreous humour in the eyeball], but in the UK we can only take stem cells from our own bodies."It is possible to get them donated, but it is safer to use your own."
In some countries, stem cells can then be manipulated in a laboratory but that is illegal in the UK, says Checkley. "There is a concern with cultured stem cells which have been bred in a Petri dish that they may keep proliferating after you transplant them into a body. That, having triggered their growth, you can't stop it and no one knows what might happen."
At the Regenerative Clinic, stem cells are taken from adipose fat, where they are plentiful, and then injected back into the area to be treated - mostly arthritic joints.
"We are seeing fantastic results," Checkley says, "with reduced pain and improved mobility for 80 per cent of patients." He is considering a clinical trial which could see the treatment pass through the National Institute for Health and Care Excellence (NICE) and become available on the NHS.
The therapy is still only four years old, he emphasises. "We have treated 1,000 patients so far and around the world, it's about 40,000. We need longer-term studies."
This type of stem cell treatment is also offered in the UK for post-menopause vaginal atrophy and stress incontinence, Checkley says, plus the genital skin condition lichen sclerosis. In all these cases, he says, the mechanism is the same: the stem cells are not replicating dead or dying cells but acting as signalling devices, alerting the body that this is an area where healing is needed.
For stem cells to work in more complex conditions, they would need to be manipulated, Checkley says. In cases of brain injury or disease, that would mean altering stem cells so that they could be targeted more precisely. But he believes the role would be similar: "The idea is they would go to the area of greatest damage and signal the body to regrow tissue there."
Cost would be a huge factor, he points out. A treatment for arthritis costs about £6,000 at the Regenerative Clinic but an IV-led treatment for brain injury with manipulated stem cells could cost up to £50,000. But then what price recovery from a traumatic brain injury? Full recovery thanks to stem cells would be a prize beyond value.
-Telegraph Media Group
