An oligodendrocyte—the type of cell that manufactures myelin.
At first, the infants seem to be progressing normally. But it soon turns out they may have vision or hearing problems, and when the time comes to lift their heads, the milestone comes and goes. It often gets worse from there. Children with the rare Pelizaeus–Merzbacher disease, like others who lack the usual insulating sheaths on their neurons, have trouble controlling their muscles, and often develop serious neurological and motor problems early in life. There is no cure for the genetic disorder. Nor is there a standardized treatment.
PMD, as it’s called, and related diseases are some of the leading candidates for potential treatment with stem cells. The idea is that if stem cells that produce the missing insulator, the fatty substance called myelin, can be successfully implanted in the brains of patients, perhaps they will pitch in what the patient’s native cells cannot.
Researchers have found a way to use human embryonic stem cells to restore hearing to gerbils. Specifically, they were able to repair damage to the nerve that connects the inner ear to the brain, as they reported in Nature this week. This type of hearing loss, which affects many people, is currently untreatable; it isn’t helped by hearing aids or cochlear implants, both of which depend on the auditory nerve to send the final signals to the brain. Applied to humans, this research could perhaps help a group that are currently without treatment for hearing loss.
A developing human egg.
What’s the News: Since the 1950s, it’s been generally accepted that women are born with all the eggs they will ever have. One gets doled out with each menstrual cycle, and when they run out, you get menopause. But a smattering of papers over the last decade or so have indicated that that dogma might be incorrect: scientists found cells in the ovarian tissue of female mice that appear capable of producing new eggs. Now, working with donated tissue, researchers have found similar cells in human ovaries.
Headlines hyping the find have been spreading across the web, and we feel compelled to point out that this paper doesn’t mean that we will be able to grow fresh new eggs in Petri dishes, and it doesn’t prove that in real, live women these cells actually mature into eggs that can develop into offspring. It does, however, provide an interesting chance to see whether egg production by these cells can be jump-started using drugs.
Researchers have announced the birth of three unusual, though healthy, baby monkeys. They are the first non-mouse chimeras—creatures made up of cells from multiple other parents—to be created by science.
Making chimeric mice is a time-consuming but fairly routine part of biology these days: embryos are injected with modified cultured stem cells containing the traits the researchers desire (like glowing in the dark). Those embryos grow up into mice who have some glow-in-the-dark cells and some normal cells, called chimeras. These chimeras are useful because if any of them have glow-in-the-dark sperm or eggs, they can be bred with each other to produce babies who are 100% glow-in-the-dark.
Cardiomyocytes damaged by a heart attack
What’s the News: Scientists are devoting countless research hours to treatments based on embryonic stem cells, differentiating these blank-slate cells from embryos into brain cells, light-sensing retinal cells, blood cells, and more to replace damaged or destroyed tissues in the body. Now, a new study in mice shows such that nature has arrived at just such a solution, too: When a pregnant mouse has a heart attack, her fetus donates some of its stem cells to help rebuild the damaged heart tissue.
For more than a decade, Geron has been a pillar of human embryonic stem cell research. They were the first to embark on embryonic stem cell trials, with a treatment for patients with spinal cord injury last year. They also have the distinction of having funded the research that isolated the first human embryonic stem cells, way back in 1998. But the company has just announced that they will be shuttering the stem cell portion of their operation.
Their spinal cord trial to assess whether a low dose of cells in a newly injured spine is safe, which had enrolled four patients, had been progressing as expected, so it’s not that they’ve lost faith in the science. It’s all about the money: Geron has two cancer drugs in clinical trials, and according to their announcement, this was the only way to continue supporting that research without having to raise more funds. They’ll be laying off 38% of their employees as a result of the decision. The four patients will continue to be monitored.
Neurons damaged by Parkinson’s disease
What’s the News: Scientists have reversed Parkinson’s disease-like brain damage and motor problems in mice and rats using neurons grown from human embryonic stem cells. The new technique, described online in Nature earlier this week, brings scientists closer to similar treatments for people with Parkinson’s.
What’s the News: Making stem cells without using embryos can be a difficult process, and scientists have had to cope with numerous failures. But a new discovery may help them home in on what’s missing from their biochemical recipes.
Biologist George Church, examining a molecular model.
George Church, the geneticist behind the Personal Genome Project, is envisioning a package deal: get your genome sequenced, and he and his collaborators will develop a line of induced pluripotent stem cells (IPS) from your tissue, so in the future, you’ll be able upgrade your system with organs and tissues bearing both your genes and special extras like genes from centenarians. It’s combining stem cells with gene therapy. In an interview with Church, David Ewing Duncan over at Technology Review asks him to elaborate. Why does he think this science fiction scenario is in our near future?
With only seven northern white rhinos left in the world, creating eggs and sperm from stem cells offers the possibility of salvaging some of the species.
What’s the News: In an effort to help preserve endangered rhinos and primates, biologists have converted skin cells taken from the animals into pluripotent stem cells, which can grow into nearly anything, given the right conditions. They might even grow into egg and sperm cells, eventually, the researchers think, suggesting a cell biological route to conservation.