Novel approach to treating tactile hypersensitivity in patients with autism-spectrum disorders
Harvard University and Deerfield Management announced today the selection of a first project for funding under the Lab1636 R&D alliance that aims to advance promising innovations from labs across the University toward the clinical development of novel therapeutics. The project arises from the lab of David Ginty, the Edward R. and Anne G. Lefler Professor of Neurobiology in the Blavatnik Institute at Harvard Medical School (HMS) and a Howard Hughes Medical Institute investigator. Lauren Orefice is a former postdoctoral researcher in the Ginty Lab and now assistant professor of genetics at HMS and Massachusetts General Hospital. In a question-and-answer session, Ginty and Orefice discuss their recent progress toward identifying possible treatments for the touch hypersensitivity that often occurs in people with autism spectrum disorders (ASD), and their hope for further innovation in neuroscience.
Q&A
David Ginty and Lauren Orefice
OTD: How do people experience touch hypersensitivity?
GINTY: Well, the truth is we don’t really know how they experience it. We do know that in certain disorders, including autism, light touch can be highly aversive. In fact, there are several examples of disorders where we see touch overreactivity; a person will react abnormally to what you and I would consider innocuous touch stimuli. For a large number of people with autism, light touch can be aversive, and normal, developmental nurturing touch may also be aversive. We refer to this phenomenon with terms like “tactile avoidance” and “tactile defensiveness.”
OREFICE: People with ASD often describe that certain types of clothing can be itchy or difficult to wear. Haircuts can even be really difficult for people to deal with, and there are certain barbers or hairstylists that they’ll go to. Things like inclement weather, heavy rain, can be really overwhelming or frightening for some people. For most of us, we are not typically aware of the fact that we are sitting in a chair, wearing a sweater, and the air conditioning is on, etcetera. But for some people with autism, some of these tactile aspects of their environment feel more present, or more profound, as though the volume is turned up.
GINTY: Interestingly, we don’t only see this tactile sensitivity in ASD. In other disorders such as neuropathic pain, which can be caused by chemotherapy, diabetes, or damage affecting the somatosensory system, light touch can also be aversive. It can be painful.
“We think there’s a critical need for normal tactile input during an early period in development. We’d like to be able to identify that critical window, to treat tactile overreactivity in young children.”Lauren Orefice
OTD: For people who are born with this, developmentally, how does it play out over the long term?
OREFICE: This is, I think, a really important aspect of what David and I do in our labs, and what we continue to ask questions about. We’re trying to understand how an abnormal sense of touch impacts the brain and ultimately complex social behaviors.
GINTY: We think that touch is the first sense to develop. The first social exchange between a baby and her parents occurs through the sense of touch. You might say that touch is where social development begins. It’s fascinating that a number of studies in humans, nonhuman primates, and other animals have suggested that normal touch is required for the development of normal cognitive processes.
In our own mouse studies, we found that if a genetic lesion that causes tactile overreactivity is introduced developmentally in the peripheral nervous system, the animals also exhibit behavioral alterations — a fairly profound anxiety-like behavior, for example, and some aberrant social-interaction behaviors. On the other hand, if the very same genetic lesions are introduced in young adult mice, the animals still exhibit the tactile overreactivity, but they don’t exhibit anxiety-like behavior. So there’s a profound link between developmental touch and tactile reactivity and the acquisition of normal behavior.
OTD: So the hope and the hypothesis is presumably that if you can address what’s happening in the peripheral nerves at the right developmental window, you may be able to prevent these kinds of things from appearing down the road.
OREFICE: Exactly. We think there’s a critical need for normal tactile input during an early period in development. We’d like to be able to identify that critical window, to treat tactile overreactivity in young children.
GINTY: Our thinking is that, even in adulthood, preventing touch overreactivity and thus tactile avoidance and defensiveness would be highly beneficial. But we hypothesize that if we could treat it developmentally, then it might also have a long-term consequence of improving anxiety and possibly even social-interaction behaviors later in life.
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