Monthly Archives: January 2012

Can Stem Cells Help Save Snow Leopards from Extinction?

Jurassic meow? Scientists at Monash University in Melbourne, Australia, have come up with a novel idea for possibly saving endangered big cats: reproduce them in the lab. And the researchers have already accomplished the first step, creating induced pluripotent stem cells (iPS) from the tissue of an endangered adult snow leopard (Panthera uncia). The research was published in the January 2012 issue of Theriogenology

Rajneesh Verma, a PhD student at Monash, told the Study Melbourne blog that he was inspired by fleeting childhood glimpses of tigers in the jungles of India and the plight these big cats currently face from poachers. “People are trying to save the habitat but poachers are still there, so we need a new solution. No one has successfully used assisted-reproduction for tigers, leopard and jaguar, but I had to give it a go. Hopefully, in [the] future I would be able to use these cells to help preserve these wild cats.”

Verma visited Australia’s Mogo Zoo, where he took tissue samples from the ears of a snow leopard, Bengal tiger, jaguar and serval. He and his fellow researchers then used the snow leopard cells to create induced pluripotent stem cells. Verma said these cells can be used either for cloning or to grow eggs or sperm in a lab. The cells could also be stored in cryopreservation for future use when eggs and sperm are too difficult to collect or freeze.

“The power of stem cells is that they can differentiate into all the cell types in the body,” Verma said in a prepared release. “This means, they have the potential to become gametes. In fact, mouse iPS cells have given rise to entire offspring, so the possibilities are enormous.”

Of course, the plan is theoretical thus far. And snow leopards—with 3,500 to 7,000 animals left in the wild—are not so endangered that an approach like this is immediately necessary to keep them from extinction. But as the Web site Wildlife News points out, techniques such as reproduction with iPS cells could be used when a species is down to its last few members and breeding options are few and far between.

In other snow leopard news, a research team working with the organizations Fauna and Flora International and Panthera has used camera traps to capture photos of the elusive felines in the mountains of Tajikistan, across the border from Afghanistan. The team lost one of its 11 cameras to a curious cub in the process. The researchers say that immediate conservation efforts are needed to protect the snow leopards in this region from poachers.

Source: John R. Platt, Scientific American


The Pill That Could Cure Depression by Growing Your Brain

 If you are depressed, or schizophrenic or have Alzheimer’s, scientists say you probably have a shrunken hippocampus. The good news: a drug that just entered human trials promises to re-grow that part of the brain.

It’s an entirely new approach to treating clinical depression, which is the first of several diseases scientists at biotech company Neuralstem are hoping to address with their experimental oral drug. Most antidepressants work on brain chemistry, tweaking levels of neurotransmitters including serotonin, norepinephrine, and dopamine. This is the first drug that aims to re-grow patients’ atrophied brains.

Dr. Karl Johe, Neuralstem’s CEO, believes that depression is a three-headed beast that affects neurotransmitter levels, neurons, and hippocampus size. And he says their new drug could address all three. He also hopes the drug will reverse the disease to the point that patients could permanently go off the drug.

“If we can show by MRI that we’ve increased hippocampus volume and at the same time reversed depression symptoms for six months after patients have stopped taking the drug, then we’ll have a cure.”

That a too-small hippocampus causes depression and other diseases is still technically a theory in humans (though it’s been demonstrated in rats and chimps). So if the drug grows hippocampus volume and thereby treats depression, we’ll not only have a new treatment, but the study results would be proof that a shriveled hippocampus is at least in part the culprit.

The scientists showed first that the drug worked in the lab: They started with dishes of neural stem cells and added several compounds they thought might instigate growth. Seven showed promise, but they could only afford to develop one, so they chose NSI-189. They then tested it in mice; after taking the drug, the rodents had larger hippocampi.

Thirty-five healthy humans have now taken the drug with no ill effects, so the FDA gave the company the OK to start testing in depressed patients. They’ll give the pill to 18 volunteers (six will get a placebo) in three groups, each receiving a progressively larger dose, each over 28 days. They expect this phase, which is mainly to make sure the drugs is safe, to take about six months. If all goes well they hope to proceed to phase two clinical trials later this year, which will test to determine whether the drug is both safe and effective. (After that, a final phase three trial to confirm safety and efficacy will remain before the company can market the drug.)

I couldn’t help thinking about those healthy test subjects who took the drug. Will they get super brain powers? The healthy mice that received the drug did grow extra large hippocampi, the seahorse-shaped part of the brain involved with both short and longterm memory and spatial navigation. Johe isn’t ruling out the possibility of souped-up brains:

“It’s an exciting possibility and we’ll definitely be looking out for it.”

Source: Gizmodo, Kristen Philipkoski

Stem Cells Offer Hope for Reversing Eye Disease

 TORONTO — Eyes have been called the window to the soul, but they are also proving to be a potential wellspring for regenerative medicine.

Researchers say they have discovered a new source of stem cells at the back of the eye, which they hope may one day provide a way to repair the damage from age-related macular degeneration, or AMD, the leading cause of vision loss in people over 60.

“We’re just thrilled to have found these cells because we know that age-related macular degeneration affects so many people, something like 10 million people in North America,” Sally Temple, a developmental neuroscientist at the Neural Stem Cell Institute, said in an interview from Albany, N.Y.

Temple’s team, whose finding is described in the January issue of the journal Cell Stem Cell, identified the central nervous system stem cells in a single layer called the retinal pigment epithelium, or RPE, which lies behind the retina.

The retina, which contains millions of photoreceptor cells, converts light into electrical signals that are sent to the brain via the optic nerve. The brain then translates those signals into the images we see.

The researchers salvaged the stem cells from the RPE layer in the eyes of more than 100 deceased donors, who ranged in age from 22 to 99. But the cells can also be isolated from the fluid surrounding the retina at the back of the eye, meaning they’re also accessible in living people.

“You can literally go in and poke a needle in the eye and get these cells from the sub-retinal space. It sounds awful, but retinal surgeons do it every day,” said Temple, adding that other neural stem cell populations would require major surgery deep within the brain.

“These cells are laid down in the embryo and can remain dormant for 100 years. Yet you can pull them out and put them in culture and they begin dividing. It is kind of mind-boggling.”

In culture dishes in the lab, the researchers were able to coax about 10 per cent of the RPE-derived stem cells to grow in the lab. Further prodding caused the cells to differentiate into, or give rise to, a variety of cell types — those that make bone, fat or cartilage.

Temple said her team also generated a progenitor cell that carries some characteristics of one type of nervous system cell, although it was not fully differentiated.

“But the fact that we could make these cells that were part-way, that were immature, indicates to us that if we keep on manipulating them, going forward in the future, we should be able to find ways to create other types of central nervous system cells,” she said.

One goal would be to produce neurons, the electrical-signalling cells in the brain and other parts of the central nervous system. That would mark a major step towards the holy grail of regenerative medicine: the ability to repair spinal cord injuries and brain damage caused by such diseases as Alzheimer’s or Parkinson’s.

“And a really important cell type that we’d love to see if we can make would be the retinal cells, the neural retinal cells like the photoreceptors that are in the eye,” said Temple. “So if we could help make new photoreceptors as well as the RPE — which we’ve already shown we can make — then we would be making two really valuable cell types for age-related macular degeneration.”

AMD is caused by damage to the central part of the retina, called the macula, which contains the photoreceptors needed for straight-ahead vision and for seeing fine details and colour. Over time, people with AMD lose the central part of their vision.

Temple said cell types generated from the stem cells could be used for testing drugs for AMD and other eye diseases, but the ultimate goal would be to regenerate eye tissue destroyed by AMD so sight could be restored.

Tests in the lab and in animals suggest the cells are stable and do not appear to cause tumours, a potential danger inherent in some types of stem cells. More animal studies are needed to determine if the cells can actually rescue lost vision, she said.

If all goes well, the first trial looking strictly at the safety of an AMD treatment using the new source of stem cells could begin in humans in about five years, Temple predicted.

These stem cells aren’t the first to be discovered in the eye. In 2000, Derek van der Kooy of the University of Toronto and colleagues identified stem cells in a part of the retina closer to the front of the eye. In late 2010, his team published a paper describing how they had used human retinal stem cells to restore sight in blind mice.

Several research groups have begun preliminary trials of stem cells in people with AMD in the hope of restoring their vision.

Valerie Wallace, associate director of vision research at the Ottawa Hospital Research Institute, said Temple’s group appears to have found a stem cell type that differs from the one isolated by the Toronto researchers.

“The advance here is showing that you can grow these cells,” Wallace said Thursday from Ottawa. “So this kind of thing could maybe help them expand those cells in culture, so maybe improve the possibility of using these RPE cells for transplantation.”

The surprising finding, she said, is that these stem cells can also give rise to fat, bone and cartilage cells — tissues that have no business being in the eyes, but which can show up there as a result of certain rare diseases. One of them, called proliferative vitreoretinopathy, or PVR, leaves scar tissue behind that can destroy vision.

“It gives us more insight into what these cells are capable of doing,” Wallace said.

When it comes to AMD, however, she cautioned that the research is still preliminary.

“If people are trying to spin it as ‘We’re closer to a cure for AMD,’ no, that’s not valid,” Wallace said. “It’s an advance in terms of basic science … This is one advance in understanding these cells and it has the potential in the future to help improve transplantation for treatment of AMD.”

Source:, Sheryl Ubelacker