Recently News

쁖irgin birth stem cells get test run

Author
Master
Date
2018-01-11 22:32
Views
60202

쁖irgin birth stem cells get test run

A NEW type of stem cell has been tested in people for the first time. Derived from 쐖irgin births, the cells have been injected into the brains of people with Parkinson셲 disease, and will soon be tried out as away of fixing physical brain injuries. Like embryonic stem cells, these cells could be a powerful treatment for a range of diseases.
Embryonic stem cells can theoretically be used to make or heal any part of the body, but they come from fertilised and discarded human embryos, which some people believe is unethical.
However, the virgin birth stem cells come from unfertilised eggs, so no life is created or ended.
This means they could be seen as morally equivalent to cells made from sperm, according to Daniel Brison at the University of Manchester, UK, who wasn셳 involved in the work. 쏛n unfertilised egg doesn셳 have any potential for human life.
Virgin births occur in a range of animals from aphids to worms, and occasionally in larger species like sharks and Komodo dragons. Through a process called parthenogenesis, females of these species can make eggs divide to form embryos without the eggs needing to be fertilised by sperm.
But this doesn셳 happen in mammals. If unfertilised human eggs are coaxed into dividing in the lab, they die after a few days.
However, stem cells extracted from these balls of cells before they die seem, like stem cells taken from embryos made using fertilised eggs, to be able to become any type of cell.
People with Parkinson셲 disease have previously shown improvements when given transplants of fetal nerve cells that release the chemical dopamine. This probably helps because the condition is caused by the death of cells in the brain that normally make dopamine, leading to symptoms like tremors.
But these transplants come from aborted fetuses, meaning the supply of such cells is limited.
Now, instead, Russell Kern of US firm International Stem Cell Corporation and his team are giving people with Parkinson셲 disease transplants of neural stem cells developed in the lab from parthenogenetic stem cells.
Work in animals suggests that some will develop into neurons that release dopamine several months after injection. Preliminary results show that, of the six people treated so far, there have been some improvements in symptoms, such as a shortening of periods when they are unable to move, the team told the Society for Neuroscience meeting in Washington DC in November.
However, it will take a larger, placebo-controlled trial to know for sure if the cells are effective, partly because Parkinson셲 disease seems particularly susceptible to the placebo effect.
Because the brain is relatively shut off from the immune system by the blood-brain barrier, the parthenogenetic cells don셳 need to be immunologically matched to each person for the treatment of Parkinson셲 disease and brain injuries. Patients are taking a modest, one-year course of immune-suppressing medicines, though, to be on the safe side, says Kern. Long-term immunosuppression would be needed if the cells are implanted elsewhere in the body.
Unlike some types of stem cell treatment, parthenogenetic stem cells aren셳 tailored for their individual recipients. One advantage of this is that they can be created years in advance and given extensive safety testing, says Kern. This means the cells might avoid the risks of induced pluripotent stem cells, which can be personalised by making them from a patient셲 skin cells, but are created in a way that can induce potentially cancer-causing mutations.
On the other hand, we still don셳 know if the virgin birth stem cells really have the same capacity for regeneration as embryonic stem cells. Sperm and egg cells have different patterns of chemical 쐇mprinting that affect the activity of different genes, so stem cells derived solely from eggs may have unusual imprinting patterns. Kern says tests show that this doesn셳 affect their ability to turn into dopamine-making neurons, however.

Source. New Scientist Magazine - December 2017



.