The old still has use...
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Posted: 01 November 2011
PARIS: Scientists said Tuesday they had transformed age-worn cells in people over 90 -- including a centenarian -- into rejuvenated stemcells that were "indistinguishable" from those found in embryos.
The technical feat, reported in the peer-reviewed journal Genes & Development, opens a new path toward regenerative medicine, especially for the elderly, the researchers said.
"This is a new paradigm for cell rejuvenation," said Jean-Marc Lemaitre, a researcher at the Institute of Functional Genomics at the University of Montpellier and the main architect of the study.
"The age of cells is definitely not a barrier to reprogramming," he told AFP by phone.
That human embryonic stem cells (ESC) can potentially become any type of cell in the body has long held out the tantalizing promise of diseased organs or tissue being repaired or replaced with healthy, lab-grown cells.
But the leap from theory to practice has proven difficult, and fraught with ethical and moral concerns because any such procedure requires the destruction of a human embryo.
The discovery in 2007 that it is possible to coax certain adult cells back into their immature, pre-specialised state has fuelled renewed efforts to generate brand new muscle, heart or even brain cells, this time from raw material provided by the patient.
Experiments to date, however, have shown that the usual chemical recipe for generating these so-called induced pluripotent stem cells (iPSC) works less well or not at all with the elderly and very elderly -- precisely the cohort with the most to gain from regenerative therapies.
The barrier was cellular senescence, a natural process linked to ageing that can trigger cell death when certain mechanisms within the cell become too degraded to function properly.
Lemaitre and colleagues decided to alter the standard genetic starter kit used to generate adult stemcells by adding two new ingredients -- known as transcription factors -- called NANOG and LIN28.
Experiments with human subjects ranging in age from 74 to 101 showed that the new cocktail worked.
Several critical markers of ageing in cells were "reset", including the size of telomeres, the tiny protective caps found on the ends of chromosomes that wear down with age, the researchers reported.
Telomeres and telomerase, the enzyme that control them, are a key agent in longevity.
Every time a cell divides, the telomeres get worn down a little bit. The enzyme's job is to partially rebuild them. Eventually, when the telomeres are worn beyond repair, a cell dies.
Gene expression profiles, levels of oxidative stress, and the metabolism of the cell's energy-generating mitochondria were all likewise rejuvenated, according to the study.
"The age markers in the cell has been erased," said Lemaitre. "The iPSC stemcells we got can produce functional cells of all types with a capacity to proliferate and enhance longevity."
By reversing the age-altered physiology of the cells, he added, the new reprogramming technique "may constitute an optimal strategy for developing cell-based therapies for aged patients."
A large gap remains between this "proof-of-concept" study and therapeutic applications, the researchers cautioned.
And recent experiments with mice suggests that generating adult stemcells may yet face unexpected barriers.
Certain kinds of iPSC may be rejected by the immune system even if they are derived from the same organism, the experiments showed.
-AFP/vl
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Taken from ChannelNewsAsia.com; source article is below:
'Rejuvenated' stemcells coaxed from centenarian
Posted: 27 September 2011
WASHINGTON: Women age 65 to 69 who break a hip face a five-times higher risk of dying within a year than their healthy counterparts, a bigger increase than in older women, said a US study on Monday.
Women 70 to 79 face double the risk of dying within a year if they break their hip compared to women who do not, and women 80 and older who break a hip face about the triple risk of dying, it said.
The study was funded by the National Institutes of Health and appears in the Archives of Internal Medicine.
"This study is a wake-up call that the first year after a hip fracture is a critical time for all elderly women, but especially for younger women, ages 65 to 69, who face a much higher death rate compared to their peers," said lead author Erin LeBlanc.
The International Osteoporosis Foundation has said there are about 1.6 million hip fractures per year, with 51 percent occurring in Europe and the Americas and most of the remainder in the Western Pacific region and Southeast Asia.
About half of all women over age 50 will break a bone because of osteoporosis, according to the US-based National Osteoporosis Foundation.
The NIH-funded study was based on data from nearly 10,000 women in four US cities who enrolled from 1986 to 1988 in a research project to track osteoporotic bone fractures.
Over the course of 20 years, 1,116 of the women enrolled suffered hip fractures. Those women were matched by age to a comparison group of 4,464 women who did not break a hip.
"Among women who broke a hip, more than half of the short-term deaths occurred within three months after the fracture and nearly three-quarters occurred within six months," added the study.
Those figures suggest that the hip fracture itself plays a major role in the deterioration of a woman's health, according to co-author Teresa Hillier, senior investigator at the Kaiser Permanente Center for Health Research.
"We also found women are at the highest risk of dying within the first three months after hip fracture, which leads us to hypothesize that hospitalization, surgery and immobility lead to other complications that ultimately result in their death."
The top three causes of death for all women in the study were heart disease, cancer and stroke.
-AFP/pn
Taken from ChannelNewsAsia.com; source article is below:
Hip break boosts death risk by five: US study
By Sara Grosse | Posted: 25 September 2011
SINGAPORE: Patients suffering from ageing corneas can benefit from a new form of corneal transplantation in Singapore.
Descemets Stripping Endothelial Keratoplasty (DMEK) is an advanced keyhole form of transplant that claims to result in almost perfect vision.
For many years, 59-year-old Chok Teck Chow's eyesight has been deteriorating.
But now, the property agent said his vision has improved greatly, as he is able to read nearly the entire eye chart.
Chok is one of only three patients who underwent the DMEK surgery about a month ago to treat his ageing cornea.
"Vision improved very much. I can see quite clearly, it's almost perfect," said Chok.
Professor Donald Tan, Medical Director of the Singapore National Eye Centre, said "DMEK is a different procedure where we are just stripping off the membrane, we're just transplanting a membrane with cells. When we peel this membrane off, we got to get it into the eye and not damage it because the moment we touch the membrane with the cells, the cells die.
"So the surgical technique on how to un-scroll the membrane, un-wrinkle it, attach it to the cornea is where the skill comes in."
The Singapore National Eye Centre has also invented a new device, which is currently under patenting, to make the DMEK surgery easier.
As the device is currently under patenting, details can't be revealed.
When asked how the corneal transplant surgery compares to artificial cornea transplants such as the Boston K-Pro, the centre had some reservations.
The Singapore National Eye Centre sees some controversies regarding the long-term success rate of the Boston K-Pro surgery, saying it potentially has some high risk complications. It recommends that the procedure be used only in cases of multiple corneal graft failures.
The eye centre said the risk of graft rejection from a DMEK surgery is 0.7 per cent.
The new procedure is expected to be performed on more patients once the new device is launched next year.
- CNA /ls
Taken from ChannelNewsAsia.com; source article is below:
New transplant method for ageing cornea patients
