Skin is the body's largest organ.
It already can be harvested to provide extra skin for burns victims and to grow cells that form cartilage and muscle.
But as scientists delve deeper into its layers, it is becoming clear that the skin might in the future hold the key to curing a range of conditions, from cancer to spinal cord repair.
And there are great hopes for skin stem cells.
The skin contains a number of different types of stem cells - it is a very interesting and accessible source of cells to restore tissue”
This week a team at Oxford University announced that specially manipulated skin cells, called induced pluripotent stem cells, can be used to generate the brain nerve cells that die in Parkinson's.
Sheila MacNeil, professor of tissue engineering at Sheffield University, said stem cell research is advancing so rapidly that it will soon be used in more applications.
"There is the potential to take a biopsy of skin from a patient with disease, culture the cells, alter them to make them grow into tissues you are interested in and also use them to study the basis of the genetic disease and then to design therapies that you can put back into the patient.
"We could be there in five years time for diseases which are well understood - like Parkinson's, and for other diseases where they are less well understood, 10 years."
She said that the 'clever thing' with the adult stem cells is that they are less likely to be rejected as they are from the donor's own body, unlike stem cells from embryos.
Although they can be harvested from across the body, the skin stem cells are easily accessible.
Professor Fiona Watt, from Cambridge University, pointed out that grafts formed by stem cells are already used to treat severe burns in patients.
"Some people forget that it is a stem cell treatment that works and which has been around a long time," she said.
"We are very interested in developing regenerative medicine as a way to heal our bodies when they can't heal themselves - when the damage from an injury or disease is too severe."
She added: "The skin contains a number of different types of stem cells - it is a very interesting and accessible source of cells to restore tissue.
"People have woken up to the idea that the skin has cells that can be turned into nerve cells and this could be a way to expand nerve cells to treat spinal cord injuries."
Professor Watt's work shows how single stem cells can be encouraged to grow in the lab on finely-patterned surfaces in order to identify the biological messages that control their ability to divide and mature into any type of cell.
Using this approach, Professor Watt's team at the Wellcome Trust Centre for Stem Cell Research, University of Cambridge, are uncovering the biology of adult skin stem cells. The methodology can also be applied to a wide range of embryonic and adult stem cells.
"I believe that the full therapeutic potential of skin stem cells is only just being appreciated," she said.
DUARTE, Calif. -- City of Hope researchers received approval from the U.S. Food and Drug Administration (FDA) to conduct the first-in-human study of a neural stem cell-based therapy targeting recurrent high-grade gliomas, the most aggressive type of brain tumor. Karen S. Aboody, M.D., associate professor in City of Hope's Department of Neurosciences, leads the research team that developed this treatment strategy. Jana Portnow, M.D., assistant professor and assistant director of the Brain Tumor Program at City of Hope, is the principal investigator for the clinical trial.
An estimated 22,500 Americans are diagnosed with malignant primary brain tumors annually, and more than 12,900 die each year from the disease. While survival rates vary with the type of brain tumor, median survival for glioblastoma, the most common type of glioma in adults, is only about 15 months. These tumors are highly invasive and ultimately resistant to current methods of treatment such as surgery, radiation and chemotherapy. One significant obstacle to curing brain tumors is the presence of the blood-brain barrier which can prevent chemotherapy agents from entering into the brain and reaching effective concentrations at tumor sites.
"This first-in-human clinical trial of a neural stem cell-based therapy that we developed at City of Hope is an investigational, targeted treatment option for recurrent high-grade glioma patients," said Aboody. "Furthermore, we envision the eventual development of neural stem cells as a platform technology for targeting multiple therapeutic agents to brain tumors, as well as other metastatic solid tumors inside and outside the brain."
Aboody and her colleagues were the first to demonstrate in 2000 the inherent propensity of neural stem cells to home in on invasive tumor cells, also known as tropism, even migrating from the opposite side of the brain or across the blood-brain barrier. Aboody's research team has since harnessed the tumor-tropism of neural stem cells to deliver therapeutic agents to invasive tumor sites, which they demonstrated in laboratory testing. The therapy uses a genetically modified human neural stem cell line, generated by Seung U. Kim, M.D., Ph.D., professor in the Division of Neurology at the University of British Columbia, to deliver a prodrug-activating enzyme (cytosine deaminase) to brain tumor sites. This enzyme converts a relatively nontoxic prodrug (5-Fluorocytosine, 5-FC), which is delivered systemically, into an active cancer-fighting chemotherapeutic (5-Fluorouracil, 5-FU). In effect, this stem cell-mediated strategy achieves production of the chemotherapeutic drug only in the area of the tumor. This investigational treatment concentrates anticancer compounds at tumor sites while minimizing exposure of surrounding healthy tissue.
"This novel tumor-selective treatment has the potential to overcome many obstacles that limit the success of currently available treatments for malignant brain tumors and other invasive cancers," said Aboody. "Using neural stem cells as delivery vehicles for therapy may allow us to target concentrated therapeutics specifically to tumor sites while reducing the undesirable side effects of current chemotherapy regimens, including toxicity to normally dividing bone marrow, gastrointestinal tract, skin and hair cells."
The clinical trial will begin accepting patients this summer, with the goal of enrolling 12 to 20 patients with recurrent high-grade gliomas. The modified neural stem cells will be injected during surgery into the wall of the cavity remaining after tumor tissue has been removed. Study patients then receive daily doses of the prodrug 5-FC for one week. Based on Aboody's laboratory findings, once the 5-FC crosses the blood-brain barrier, the neural stem cells will convert the 5-FC to the active chemotherapy agent, 5-FU, at tumor sites in the brain. The phase I safety trial will assess the maximum tolerated dose of the therapy, and is supported by a grant from the National Cancer Institute, part of the National Institutes of Health.
Human veins left over from lifesaving bypass surgery could be a source of "master" cells to help treat future heart problems, say scientists.
A University of Bristol team extracted stem cells from the veins, then used them to stimulate new blood vessel growth in mice, Circulation reports.
The researchers say their findings could bring treatments to repair damaged heart muscle one step closer.
However, a stem cell expert warned that they remained some years away.
Stem cells are attractive to medical researchers because they have the ability to produce many different types of human cell, opening up the possibility of repair or renewal for tissues ravaged by disease or injury.
While human embryos were originally seen as the prime source of "pluripotent" cells, with the potential to form virtually any tissue type, scientists are increasingly finding ways to isolate cells from adults which have some of these properties, and encourage them to multiply into useful numbers.
The latest discovery uses a "waste" product from thousands of operations carried out on heart patients each year.
Patients with heart disease often have blocked or narrowed arteries supplying the heart muscle.
The lack of blood leaves the muscle damaged, and this can cause chest pain or even a heart attack.
A heart bypass operation takes a section of vein, usually from the patient's leg, and uses it to replace a blocked or narrowed section of heart artery.
The surgeon normally takes a slightly longer section than is actually required.
In this study, the Bristol team took the leftover piece and, in the laboratory, they managed to extract "progenitor" cells from the veins and persuade them to increase in number.
Mouse muscle
When the stem cells were injected into the leg muscle of a mouse which had been deprived of blood to simulate conditions in a damaged heart, the cells appeared to trigger the development of new blood vessels and improve blood flow.
Professor Paolo Madeddu, who led the research, said: "This is the first time that anyone has been able to extract stem cells from sections of vein left over from heart bypass operations.
"These cells might make it possible for a person having a bypass to also receive a heart treatment using their body's own stem cells."
However, other experts said much more work would be needed before such cells could be used widely in humans.
Professor Qingbo Xu, from King's College London, said the mechanisms by which the cells worked needed to be more fully understood.
"It's possible this could be a future treatment, although not at the same time as the heart bypass surgery, as it takes some time to extract and grow these cells in the laboratory.
"But there is a long way to go before we can have a clinical application for this."
Professor Peter Weissberg, the medical director of the British Heart Foundation, which funded the research, said the prospect of repairing heart damage was the "holy grail" for heart patients.
He said: "It brings the possibility of 'cell therapy' for damaged hearts one step closer, and, importantly, if the chemical messages produced by the cells can be identified, it is possible that drugs could be developed to achieve the same end."
It is hoped that using the boy's own tissue in the nine-hour operation at Great Ormond Street Hospital will cut the risk of rejection.
The world's first tissue-engineered windpipe transplant was done in Spain in 2008 but with a shorter graft.
Doctors say the boy is doing well and breathing normally.
He has a rare condition called Long Segment Congenital Tracheal Stenosis, in which patients are born with an extremely narrow airway.
At birth his airway was just one millimetre across.
Doctors had previously operated to expand his airway but in November last year he suffered complications from erosion of a metal stent in his windpipe or trachea.
In order to build him a new airway, doctors took a donor trachea, stripped it down to the collagen scaffolding, and then injected stem cells taken from his bone marrow.
The organ was then implanted in the boy and over the next month, doctors expect the stem cells to transform into specialised cells which form the inside and outside of the trachea.
Two years ago, Claudia Castillo, a 30-year-old mother of two, became the first person to receive a transplant organ created from stem cells.
She received a new section of trachea after her own had been damaged by tuberculosis.
The latest operation is a significant advance on that pioneering work, as it is the first time a whole tissue engineered windpipe has been transplanted.
Also in Ms Castillo's case, doctors grew the new tissue from her stem cells in the laboratory.
But in the UK operation, the donor windpipe was treated with a cocktail of chemicals designed to prompt the stem cells to grow into new tissue once inside the body.
Professor Martin Birchall, head of translational regenerative medicine at University College London, who was part of the team behind the operation, said it was a "real milestone".
"It is the first time a child has received stem cell organ treatment, and it's the longest airway that has ever been replaced.
"I think the technique will allow not just highly specialised hospitals to carry out stem cell organ transplants."
He said more clinical trials were needed to prove the technique worked but that the team was also thinking about transplanting other organs, such as the oesophagus.
Professor Anthony Hollander, ARC professor of rheumatology and tissue engineering at the University of Bristol, said: "The advantage of the new approach is that it can be performed quickly and cheaply and so if successful it could be made available to large numbers of patients at relatively low cost."
But he said the technique was more unpredictable than that done in the laboratory because there is less control of the type of stem cells being used and a very short time between seeding the cells onto the scaffold and implantation.
Stem cell pioneer Professor Paolo Macchiarini, from Careggi University Hospital in Florence was involved in both the Spanish and UK transplants.
He had also carried out the stem cell procedure on a 53-year-old Italian woman.
Also in Ms Castillo's case, doctors grew the new tissue from her stem cells in the laboratory. He had also carried out the stem cell procedure on a 53-year-old Italian woman.
news.bbc.co.uk/1/hi/health/8576493.stm
They manipulated a "signalling pathway" in the stem cells to trigger an increase in numbers without losing their stem cell status.
news.bbc.co.uk/1/hi/health/8462488.stm
The BBC's Matt McGrath visited a private firm, StemLifeLine, who specialise in using stem cells to test new drugs for cancer, and also have a stem cell bank.
www.bbc.co.uk/worldservice/news/2010/02/100222_stemcells.shtml
www.bbc.co.uk/worldservice/lg/news/20.../100222_stemcells.shtml
Since graduating i have made 3 films, annotate (cineworks), The Atomists (Bridging the gap) and A Stem Cell Story, an educational film explaining the basic science regarding stem cells.
www.bbc.co.uk/filmnetwork/users/13628621
Another alternative is to grow meat in laboratories from stem cells.
www.bbc.co.uk/bloom/actions/eatinglessbeef.shtml
Over the last month, it's been hard to miss all the news stories about stem cell therapy. Stem cell treatments have been successful in treating and a few other conditions in research settings.
www.bbc.co.uk/ouch/fact/what_s_all_this_about_stem_cells_.shtml
Stem cells are taken from the patient's bone marrow and are given chemical signals that persuade them to become cartilage cells. Peter also hears about a novel approach to stem cell research.
www.bbc.co.uk/radio4/science/frontiers_20060607.shtml
Could stem cells be used to treat such degenerative disorders effectively? The source of the stem cells - early embryos - is distasteful to some.
www.bbc.co.uk/radio4/science/cellforallseasons.shtml
How can stem cells be used in medicine? After watching it, students could be asked to explain what stem cells are, where they come from and why they can be used in medicine.
www.bbc.co.uk/learningzone/clips/stem-cell-research/6013.html