Thursday, November 10, 2011

Animal Testing Research

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Male Professor: As you all know, in September 2005, a team of international scientists were able to draft a genome sequence of the common chimpanzee and compare it to the human genome. The results? Over 98 percent of our DNA is identical with that of chimps, a fact that suggests chimps are biologically more closely related to humans than they are to gorillas even. Other methods of comparisons give a more conservative estimate that says the differences are closer to 4 or 5 percent. At the end of the day, however, it’s safe to say that chimpanzees are humans’ closest biological cousins.

Female Student: Wait, did you say that chimps are closer to humans than they are to gorillas? That sounds crazy to me. Chimps and gorillas look so much more similar to each other than chimps and humans.

Male Professor: Yes, well, we’re talking genetics here, not appearances. And that particular fact comes from the Jane Goodall Institute, which is a world-class chimpanzee research facility. But anyway, that’s not the most important issue here. Today, I want to talk about the pros and cons of using great apes, which include the chimps and gorillas, but also orangutans and bonobos, in scientific research.

            Because of their similarities to humans, the great apes, and chimpanzees in particular, are often viewed as appropriate stand-ins for humans in studies of disease processes, experimental procedures, and behavioral research. A recent study at the California National Primate Research Center tested whether damage to lungs caused by exposure to air pollutants could be reversed if the exposure were removed. Researchers hoped to gain a deeper understanding of asthma and other respiratory diseases. In terms of research for experimental procedures, scientists have been using primate stem cells to learn about how stem cells can be used in regenerative medicine. The idea of stem cell research is that cells damaged by disease, injury, or aging can be replaced by regenerated cells. Such cell therapies are particularly promising for Parkinson's Disease, a neurodegenerative disease which causes movement and sensory difficulties.

            Particularly interesting have been behavioral studies of apes. A study published in 2007 reveals that chimpanzees show altruism, a trait thought to be found only in humans. In one study of chimpanzees at the Max Planck Institute for Evolutionary Anthropology in Germany, a chimpanzee would try to enter a locked room that had food in it. Another chimpanzee who was watching would unlock the door to help the first chimp enter the room. This altruistic behavior wasn’t limited to just other apes, either. In another test, a chimp would observe a human reaching through bars to try to get a stick that was on the other side. The stick would be placed out of the human’s reach. In these tests, the chimpanzees would spontaneously pass the stick to the person, even if they were not rewarded, and even if the stick was far away and required the chimp to climb several feet to get to it.  

Female Student: Wow, that’s really surprising. You’d think that chimpanzees wouldn’t want to help the people who perform experiments on them.

Male Professor: It is indeed surprising, and it raises a couple of questions which are leading many researchers to think twice about using apes in scientific research. The first question is, “Why do we continue to use apes as research subjects? Hasn't technology provided us tools to replace the apes?”

            The answer is that yes, technology has developed blood tests and tissue cultures that can effectively replace apes in some experiments. For example, pharmaceutical companies can test the toxicity of chemicals in vitro rather than in vivo. In other words, they can test chemicals in a test tube rather than test it in a living ape. However, one possible problem is that cytotoxicity in vitro might not mirror in vivo results. That is, something that is poisonous to a cell in a test tube might not be poisonous to a cell in a living being.

            A second common question is whether or not the benefits outweigh the costs of using apes in medical research. Primates are very expensive animals to raise in captivity, and because they are particularly sensitive to the stress of being used in medical experiments, some researchers think that they are not ideal candidates for medical research. After all, stress can skew experimental outcomes. Also, there are some diseases that do NOT affect apes in the same ways that they affect humans. For example, one disease for which apes were expected to provide information was AIDS. However, researchers have found that in chimpanzees, HIV seldom progresses to AIDS. The program has failed. And now there are hundreds of chimps that were injected with HIV that currently need to be cared for and housed for the remainder of their lives―up to 50 years. That's 50 years of research money that is unavailable for anything else. At a lifetime cost of $300,000 to $500,000 per chimpanzee, that is a gargantuan expenditure.

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