The Primate Directive
Could the key to reversing human autism be found in the monkey trials at a little-known NIH facility? That’s what researchers there hope, as they work to unlock the mysteries behind that and other human diseases and disorders
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About a decade ago, scientists identified 5-HTT as the gene in humans that regulates serotonin, a neurotransmitter that affects mood. Serotonin irregularities are associated with anxiety and depression. In humans, the 5-HTT gene always has two variants called alleles. When one of those alleles is shorter than the other, the person appears to be vulnerable to anxiety or depression following stressful events.
Similar gene variants have been discovered in rhesus monkeys. But Suomi has learned that proper nurturing by the mother can prevent anxiety and depression.
“We have learned that genes aren’t destiny,” says Suomi, who lives in Bethesda and has been interested in animals and learning what makes people tick since growing up in Madison, Wis. “They don’t operate by themselves, but rather, they interact with experience.”
Researchers have found a similar dynamic between genes and the environment in people, says Helen Tager-Flusberg, a professor of anatomy, neurobiology and pediatrics at Boston University Medical School and president of the International Society for Autism Research.
“Suomi is undoubtedly the most preeminent researcher in the field of primate development,” Tager-Flusberg says. “We learn from what he is doing.”
Most recently, Suomi’s observations of monkeys’ interactions have suggested a potential early way to detect autism and possibly deter its effects. Most infant monkeys mimic their mothers’ facial expressions, much as human babies “mirror” their mothers’ expressions. But about a third of the monkeys that don’t imitate their mothers develop autistic type behaviors later, repetitively pulling their hair or banging their heads, for instance.
Suomi’s researchers further discovered that non-imitative monkeys seemed to focus on their mothers’ lips, not their eyes. In humans, eye-to-eye contact is key to mother-baby bonding.
To test whether the monkeys could be trained to focus on their mothers’ eyes and perhaps avert the development of autism, Suomi’s researchers created a computer avatar of a mother rhesus monkey with large, exaggerated eyes. Through eye-tracking technology, the researchers could see if the monkeys could be prodded into looking at their “mothers’ ” eyes and redirected onto a normal developmental track. A special helmet created for the infants enabled Suomi’s researchers to study the monkeys’ brain waves to determine if the non-imitators’ brains would develop more normally. At press time, Suomi’s team was still analyzing the data and hoped to publish the findings by year’s end.
“We are discovering that what is going on in the first few days and weeks of life is probably more important than we thought,” Suomi says.
With autism diagnoses rising in this country, the impact of Suomi’s work could be “a real discovery, because it would mean there is a possibility for remediation,” says Nathan Fox, a distinguished professor at the University of Maryland who specializes in neuroscience and developmental psychology and worked with Suomi on the project.
Tager-Flusberg notes that even if it doesn’t directly translate into human treatment, it could lead to other ideas.
Suomi also collaborates on studies looking at the use of antidepressants in juvenile monkeys and their impact on the later development of personality. And he’s looking at whether genetics plays a role in alcoholism; the impact of environment on the immune system; how the environment affects aging; and how genes determine metabolism and obesity.
Suomi is so involved in his various research projects and travel that he has little time for a personal life: He’s single, and “I don’t have kids or pets, just 400 monkeys and friends with dogs and cats,” he says.
It’s nearly feeding time for the pigs, and their squeals almost drown out Dr. Tanya Burkholder, the chief of the Veterinary Medicine Branch of NIH’s Division of Veterinary Resources, as she doles out jelly beans.
“They know when one of them is getting a treat, and the [others] want one, too,” she says as she reaches down to scratch a pig’s ear. The creature turns its face aside in delight.
Kris Eckard, facility manager of the Division of Veterinary Resources at Poolesville, says the staff often gives out treats when handling the animals or administering medication. “Pigs like jelly beans, Fig Newtons and Caramel Creams,” she says.
While Woodward oversees about 400 monkeys involved in research, Burkholder is involved with watching over the rest of the animals at the facility. Houston-raised, and married with two cats, she projects a friendly, no-nonsense style.
She previously had a career in business, but “I was working as a consultant, and one of the jobs I had was for the National Zoo, largely on fundraising, and I found I was much more interested in what the scientists and veterinarians were doing,” says Burkholder, who has worked at Poolesville for 10 years. “So I decided to become a vet.”
She and Woodward make sure the animals are treated according to guidelines set by the Animal Welfare Act, the NIH’s Office of Laboratory Animal Welfare and the Association for Assessment and Accreditation of Laboratory Animal Care International. That includes standards for handling, housing, sanitation, feeding, minimizing pain and other care practices for animals, as well as the protection of employees, such as the types of clothing they must wear to prevent injury or disease from spreading between humans and animals.
In addition, researchers must consider the animals’ psychological well-being, which means that social animals such as monkeys must be housed together unless there’s a compelling reason not to, and must be provided with environmental enrichment and exercise.
The Poolesville property is split into a “north” and “south” side. Suomi’s research and primate breeding occur on the south side; most of the holding, quarantining and other research occurs on the north side. Monkeys get time outside in large cages, some of which resemble giant corncribs. There are hidden treats and swings, food is varied, and families are housed together.
About 80 monkeys also live in the protected 5-acre outdoor enclosure built for Suomi. The monkeys are free to roam, climb on trees, play on jungle gyms or swim in a large natural pond.
On the north side, many of the animals live inside but have access to the outdoors. Rhesus and long-tailed macaques occupy large, square habitats, with one wall made entirely of glass so that visitors can see them playing and eating. The monkeys can climb between the different rooms or go outside to play.