Tag: Mice

Drug Extends Life Span in Mice

Technology Review has a story on the first drug demonstrated to expand the lifespan of a mammalian species. In this case, rapamycin was administered late in the life of mice and extend lifespan by an average of 9 percent in males and 13 percent in females.

According to TR, rapamycin is already approved in the United States for use as an immunosuppressive drug for organ transplant recipients and is being tested for its potential to treat cancer.

The drug may act as a chemical form of caloric restriction, the only other method known to significantly extend lifespan in mice,

Experts believe it’s possible that rapamycin may tap into one of the same biochemical pathways as calorie restriction, an intervention long known to make mice live longer. While the drug was not as effective as a limited diet initiated early in life, it was far more powerful than a limited diet begun at the same advanced age. In ongoing studies, the researchers are testing different doses across a range of starting ages; an optimal combination may ultimately prove more potent than calorie restriction.

That would certainly be nice.

PETA Award to Person Who Perfected Mouse Killing Technology

People for the Ethical Treatment of Animals recently named Dr. Nigel Binns as its Person of the Year. Binns’ major accomplishment? He developed an extremely effective way to kill mice.

According to a PETA press release,

Unlike cruel poisons, snaps, and glue traps — which can cause mice and rats to suffer in agony for hours or days — the RADAR trap painlessly gasses trapped rodents with carbon dioxide.

Binns is chief biologist for UK pest control company Rentokil. According to a New Scientist story on his trap,

Nigel Binns, Rentokil’s chief biologist, wanted a trap that would kill only target animals, and do so humanely. It would then alert a pest controller that the trap needed attention. Inside its white plastic enclosure, a pressure pad senses the weight of an animal’s paw, and closes the door if the footfall matches the weight of a rat or mouse. Squirrels or small rabbits are spared, he says. Gas released from a carbon dioxide capsule then kills the vermin humanely.

Binns tells New Scientist that computer data centers might be one big customer of his trap, since its constant monitoring and instant notification would help reduce rat problems that some data centers have experienced.

Sources:

Builder of more humane mousetrap recognized as PETA’s ‘Person of the Year’. Press Release, People for the Ethical Treatment of Animals, 2005.

UR r@ is in the trap. New Scientist, November 17, 2005.

Researchers Grow Stem Cells Without Direct Use of Animal Cells

In March, researchers at the Roslin Institute in Scotland reported they had managed to grow stem cells without directly exposing the stem cells to animal cells, though the stem cells were still indirectly exposed to animal cells.

Until now, embryonic stem cells are grown using mouse feeder cells and in animal growth serum. There is some concern that as long as animal cells are used in the process that there is a risk that an animal virus will be transmitted to human beings who might someday receive stem cell transplants.

The Roslin Institute researchers used human protein laminin and feeder cells taken from human neonatal foreskin cells to provide the nutrients that the embryonic stem cells need.

This process is still not entirely animal-free, however, as the neonatal human foreskin cells are themselves grown in a process which uses animal cells.

Almost certainly at some point embryonic stem cells will be grown end to end in non-animal substrates at which point the animal rights movement will claim that animal research had nothing at all to do with embryonic stem cell research.

Sources:

Human embryonic stem cells grown animal-free. Andy Coghlan, New Scientist, March 17, 2005.

‘Animal free’ stem cells created. The BBC, March 16, 2005.

OSU Responds to PCRM’s Claims about Spinal Cord Injury Course

As I mentioned earlier this year, Physicians Committee for Responsible Medicine filed a complaint with the National Institutes of Health claiming about an NIH-funded class at Ohio State University that trains researchers to injure the spinal cords of mice and rats so the animals can be used in spinal cord research. PCRM claims the course is in violation of the Animal Welfare Act and involves cruelty to animals.

OSU recently responded to an NIH request for a response to PCRM’s charges.

According to OSU student newspaper The Lantern, PCRM’s letter claimed that the researchers first performed multiple operations to impair the animals’ spinal cords and then force them to perform a number of task,

The animals are surely in a large amount of post-operative pain in addition to the complications they might experience as a result of their injury. This OSU course violates efforts designed to avoid or minimize such pain and distress to the animals.

In its response to the Office of Laboratory Animal Welfare, OSU responded that a) the animals undergo only a single major surgery, b) animals are medicated for pain, c) behavioral study of the animals doesn’t occur until after the animals have recovered from the surgery, and d) the behavioral research does not involve forcing the animals to perform, but rather offers the animal rewards for performing certain tasks.

According to OSU’s response,

The instructors prepare a cohort of animals with spinal cord injury to train students in the proper conduct of behavioral testing. Testing does not commence until the animals are well recovered from surgery.

In her letter to the Office of Laboratory Animal Welfare, PCRM’s Kristie Stoick wrote that there are alternatives to using animals for such training purposes,

Alternatives range from shadowing a researcher and the use of simulation and models to videotaped technique demonstrations.

OSU spokesman Earle Holland responded that this is simply not the case, telling The Lantern,

There are no available altenratives for whole organisms. If there were equivalent methods, every researcher would jump at the idea of not using animals. It’s really ludicrous. It’s just not true. Researchers would be using them. No one enjoys doing things to animals that are undesirable.

In its letter, OSU wrote that it formed a subcommittee of its Institutional Laboratory Animal Care and Use Committee that investigated the course and considered the possibility of non-animal alternatives,

By properly training new researchers in the current best practices, the potential for poorly performed experiments will be less, thereby allowing refinement and/or reduction of animal numbers. The investigators (and) instructors pride themselves on the high level of care given to the animals and are dedicated to teaching others to deal with their subjects carefully, compassionately, and to respect both animal and human life.

OSU is currently awaiting a response from the Office of Laboratory Animal Welfare.

Source:

OSU denies animal cruelty complaints. Susan Kehoe, The Lantern (Ohio State University), February 28, 2005.

Study Suggests It May Be Possible to Transplant Animal Embryonic Stem Cells to Grow New Human Organs

In a study published in February in the Proceedings of the National Academy of Sciences, researchers at the Weizmann Institute of Science published the results of their experiments in implanting embyronic stem cells from pigs into mice.

The researchers wanted to establish at what point it was best to implant the embryonic stem cells, so it took stem cells from varying stages of development of the pig embryo, and implanted them in the liver, pancreas and lungs of immune-deficient mice.

The researchers discovered that transplanting embyronic stem cells at too early or too late a stage would not result in new cell growth, but that if transplanted during the correct window of opportunity, the pig stem cells did lead to cell growth in the mice. Dr. Bernard Herring, at the Diabetes Institute for Immunology and Transplantation at the University of Minnesota, told National Geographic News,

What he [lead researcher Yair Reisner] has shown is that there’s a window of opportunity . If you obtain this tissue at a very defined point in time, then you can see development into islets [portions of the pancreas that secrete hormones like insulin] without risks such as teratoma formation. That’s clearly something that makes us feel very strongly that this could be a real opportunity, one that can be translated into tangible benefits much faster than other technologies.

In a statement about the research, Reisner said,

Considering the ethical issues associated with human embryonic stem cells or with precursor tissue obtained from human abortions, we believe that the use of embryonic pig tissue could afford a more simple solution to the shortage of organs.

This finding helps explain, in part, why previous efforts to transplant pig embryonic stem cells failed, since previous research had harvested the cells at a much later gestational age than what Reisner’s study found was optimal.

Of course there are still a number of major hurdles to overcome before such technologies could be used in human beings even if researchers figure out how to make embryonic stem cells produce cells in human beings, including producing pigs free of viruses that could possibly infect human beings and avoiding an immune response to the transplant of such cells.

Sources:

Pig Stem Cells to Be Used to Grow Human Organs? Stefan Lovgren, National Geographic News, February 15, 2005.

New Organs Could Come from Pig Embryos – Study. Reuters, February 14, 2005.

Canadian Researchers Isolate Stem Cells in Brain Tumors

Canadian scientists recently published the results of their research identifying stem cells in brain tumors that keep the tumor growing. The research was published in the Nov. 18 issue of Nature.

It was already known that breast cancer and leukemia use stem cells to quickly grow and regenerate when they are threatened with destruction, but the finding that brain tumors also utilize stem cells suggests that this is a common mechanism used by cancerous tumors.

Researchers first isolated stem cells from other cells in cancerous human tumors. They did this by extracting cells in the tumors that were producing a protein commonly found on the surface of other stem cells. They then injected 100 of these cells into mice.

Sixteen of the 19 mice injected with these cells developed cancerous brain tumors. This is the first time that researchers have demonstrated that such cells can indeed cause cancer itself.

According to Nature,

Moreover, the cancer stem cells grew into tumors that behaved similarly to those in the patients from which they came, resembling glioblastomas and medulloblastomas, for example. This suggests that mice tumors will be a good way to study the human disease.

Sources:

Stem Cells Feed Brain Tumors. Kristen Philipkoski, Wired, November 17, 2004.

Stem cells home in on brain cancer. Jim Giles, Nature, October 25, 2004.