Could early stem cell trials cure blindness?
After more than a decade of anticipation, clinical trials of human embryonic stem cells are getting under way. Last week US regulators allowed Advanced Cell Technology, a stem cell company based in Massachusetts, to begin treating patients who suffer from a common form of juvenile blindness.
After ACT provided reassurances about the procedure’s safety, the US Food and Drug Administration lifted the “clinical hold” it had put on the trial. ACT will use retinal cells derived from human embryonic stem cells to treat Stargardt’s disease, a form of macular degeneration that usually starts between the ages of 10 and 20.
It will be the world’s second clinical trial of embryonic stem cells. Geron, a Californian company, started the first trial last month to treat acute spinal cord injury.
“I think future generations will look back at this time as one of the most exciting in the history of medicine,” says William Caldwell, ACT’s chief executive. “With this clinical trial and Geron’s, the field of regenerative medicine is poised to take embryonic stem cell therapies from the realm of nebulous potential to that of tangible and real treatments that will make a difference to millions of people.”
Patients are also beginning to receive treatments derived from foetal stem cells – ReNeuron of the UK has just started a clinical trial on stroke patients. These stem cells are scientifically distinct, coming originally from foetuses at a later stage of development than the very early embryos used as the source of embryonic stem cells.
ACT’s new cells are intended to replace the patient’s lost retinal cells. The procedure worked well in experimental rats and mice.
“The results of [retinal] cells implanted in the various animal models of macular degeneration were phenomenal,” says Raymond Lund, a retinal expert working with the company. “If ACT observes even a fraction of that benefit in humans, it will be nothing short of a home run.”
The trial will involve 12 patients at eye institutes across the US. The first three volunteers will receive an injection of 50,000 cells at the back of the retina, and if all goes well the dose will be increased to 250,000 cells for the final three. The company will seek permission for a similar trial in Europe soon.
The eye is an excellent target for cell therapy because the ocular immune system does not reject cells from a genetically different donor.
ACT is also developing a stem cell treatment for age-related macular degeneration. Other stem cell research groups have similar targets, such as the London Project to Cure Blindness, led by Professor Pete Coffey at University College London in collaboration with Pfizer, the US pharmaceutical giant.
A naturalist’s dream – in East Anglia
Britain’s biodiversity hotspot is … the Breckland in East Anglia. Covering 1,000 sq km on the Norfolk-Suffolk border, it includes the country’s largest lowland forest, its only inland sand dunes, heathland, pine forest, farms and wetland.
The Breckland covers only 0.4 per cent of the UK’s land area but contains an astonishing 28 per cent of its rare and threatened species, according to an unprecedented “biodiversity audit” led by scientists at the University of East Anglia.
The project, which included several national and local conservation bodies, is believed to be the first in the world to attempt to record every plant and animal species in a region, from the tiniest gnat to the tallest trees.
With the help of 200 naturalists, UEA collated nearly a million records, showing that 12,500 species can be found in the region. Of these, more than 2,000 are of national conservation concern.
The team went on to analyse the ecological needs of these rare species, which allowed them to identify novel approaches for managing habitats to restore and protect their biodiversity.
“These exciting findings demonstrate beyond doubt what conservationists have long suspected – that the Breckland is a vitally important hot spot for rare and threatened species, making it a key area for conservation within the UK,” says Paul Dolman, the study’s leader. “Although much of what conservation has achieved is excellent, new approaches are urgently needed or we risk many of these species drifting towards extinction.”
Because the sandy soil made ploughing easy, Breckland was one of the first places in England to be cultivated. The medieval word “breck” meant a fallow cropped field and light cultivation remains crucial to many rare farmland species, and therefore to biodiversity. “We need to put the brecks back into Breckland,” says Dolman.
For your drinking pleasure
An estimated 8 per cent of wine consumers suffer allergic reactions significant enough to reduce the pleasure of drinking. We are not talking here about too much alcohol but a reaction to other compounds in the wine.
Experts are not clear exactly what triggers wine allergy. Although sulphites (added to prevent spoilage) used to take a lot of the blame, they affect only about 1 per cent of drinkers. Suspicion now falls on glycoproteins – proteins with sugar molecules attached, which are generated naturally as grape juice ferments.
Researchers at the University of Southern Denmark have analysed a 2008 Italian Chardonnay for glycoproteins. They found 28 compounds. Some originated in the grapes, some in the yeast. Many had molecular structures similar to known allergens, including ones that trigger reactions to ragweed and latex.
The researchers say their discoveries – published in the Journal of Proteome Research – could open the door to winemaking processes that offer the prospect of less allergenic wine. In addition, some glycoproteins affect the formation of haze in wine. So the research could help winemakers produce the crystal-clear liquid that most drinkers want.
Underwater love: why fish like a winner
If a lady sees her lover lose a competition, does her subconscious start to whisper, “He’s a loser”? Might the defeat begin to undermine her attachment?
Yes, according to experiments with African cichlid fish at Stanford University. When a female fish showed a preference for a particular male and then saw him defeated in a fight with another male, there was increased activity in her brain areas associated with anxiety. If her favoured male was victorious, activity rose in other areas associated with sex and pleasure.
The human brain has the same primitive areas – and Julie Desjardins, the Stanford project’s leader, suggests people may react subconsciously in a similar way.
“It is the same as if a woman were dating a boxer and saw her potential mate get the crap beat out of him really badly,” she says. “She may not consciously say to herself, ‘Oh, I’m not attracted to this guy anymore because he’s a loser,’ but her feelings might change anyhow.”
Her colleague Russ Fernald adds: “Our intuition is that this response is likely to occur under similar conditions in humans because the brain areas involved are present in all vertebrates and perform comparable functions.”
The Stanford fish experiments were carried out in tanks where the researchers could control the interactions between the territorial males, which fight at every opportunity, and females that form attachments to specific males. Sadly, the only way of analysing the female brain was to kill the fish as soon as it had witnessed the males fighting. The next stage will be to observe the fishes’ post-fight behaviour.
“Now that we know the females consistently react to the fights so strongly, we should be able to answer the burning question,” says Desjardins. “Will she dump the loser she used to like in favour of the winner?”
President Obama has ordered a review of the US regulations that protect human participants in scientific research. This follows an outcry after reports that US officials infected Guatemalans with sexually transmitted diseases in the 1940s.