A new study involving children with Williams syndrome (WS) suggests that improved regulation of oxytocin and vasopressin may someday improve care for autism, anxiety, post-traumatic stress disorder and WS.
WS results when certain genes are absent because of a faulty recombination event during the development of sperm or egg cells. Virtually everyone with WS has exactly the same set of genes missing (25 to 28 genes are missing from one of two copies of chromosome 7).
“The genetic deficiencies allow researchers to examine the genetic and neuronal basis of social behavior,” said Ursula Bellugi, Ph.D., a co-author on the paper.
“This study provides us with crucial information about genes and brain regions involved in the control of oxytocin and vasopressin, hormones that may play important roles in other disorders.”
In the study, scientists at the Salk Institute for Biological Studies and the University of Utah, found that people with WS flushed with the hormones oxytocin and arginine vasopressin (AVP) when exposed to emotional triggers.
Children with WS love people, despite being challenged with numerous health problems. WS kids are extremely gregarious, irresistibly drawn to strangers, and insist on making eye contact.
They have an affinity for music. But they also experience heightened anxiety, have an average IQ of 60, experience severe spatial-visual problems, and suffer from cardiovascular and other health issues.
Yet despite their desire to befriend people, WS kids have difficulty creating and maintaining social relationships — an issue that obviously affects many people without WS.
In the new study, led by Julie R. Korenberg, M.D., 21 participants, 13 who have WS and a control group of eight people without the disorder were evaluated at the Cedars-Sinai Medical Center in Los Angeles. Because music is a known strong emotional stimulus, the researchers asked participants to listen to music.
Before the music was played, the participants’ blood was drawn to determine a baseline level for oxytocin. Remarkably, those with WS had three times as much of the hormone as those without the syndrome.
Blood also was drawn at regular intervals while the music played and was analyzed afterward to check for real-time, rapid changes in the levels of oxytocin and AVP.
While other studies have examined how oxytocin affects emotion when artificially introduced into people, such as through nasal sprays, this is one of the first significant studies to measure naturally occurring changes in oxytocin levels in rapid, real time as people undergo an emotional response.
Although the WS participants displayed little outward response to the music, an analyses of blood samples showed that the oxytocin levels, and to a lesser degree AVP, had increased sharply while they had listened to the music.
In contrast, among those without WS, both the oxytocin and AVP levels remained largely unchanged as they listened to music.
Korenberg believes the blood analyses strongly indicate that oxytocin and AVP are not regulated correctly in people with WS, and that the behavioral characteristics unique to people with WS are related to this problem. “This shows that oxytocin quite likely is very involved in emotional response,” she said.
In addition to listening to music, study participants already had taken three social behavior tests that evaluate willingness to approach and speak to strangers, emotional states, and various areas of adaptive and problem behavior.
Those test results suggest that increased levels of oxytocin are linked to both increased desire to seek social interaction and decreased ability to process social cues, a double-edged message that may be very useful at times, for example, during courtship, but damaging at others, as in WS.
“The association between abnormal levels of oxytocin and AVP and altered social behaviors found in people with Williams Syndrome points to surprising, entirely unsuspected deleted genes involved in regulation of these hormones and human sociability,” Korenberg said.
“It also suggests that the simple characterization of oxytocin as ‘the love hormone’ may be an overreach. The data paint a far more complicated picture.”
Overall, the researchers say, their findings paint a hopeful picture, and the study holds promise for speeding progress in treating WS, and perhaps autism and anxiety through regulation of these key players in human brain and emotion, oxytocin and vasopressin.
The study is published in the journal PLoS One.
Source: Salk Institute