Itch Perfect: The Israeli Scientist Scratching Away for Radical Cures

Not content with trying to find a way of neutralizing itches, Dr. Alexander Binshtok is also working to revolutionize the world of anesthesia and ease your pain.

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Dr. Alexander Binshtok at the Hebrew University of Jerusalem.
Dr. Alexander Binshtok at the Hebrew University of Jerusalem.Credit: Hebrew University

In Dante’s “The Divine Comedy,” the liars and fakers who are taken through the gates of hell are doomed to a terrible punishment – nonstop itching for all eternity. Severe or chronic itching, experienced as an uncontrollable urge to scratch and rub the skin, can be quite torturous. It is a symptom of many illnesses, and a side effect of certain medications. Some terminal cancer patients, for example, experience such severe itching in response to morphine that they elect to live with the pain rather than take the drug.

Scientists believe that itching – and the scratching reflex it triggers – is an evolutionary remnant of an action that was meant to remove parasites that had penetrated the skin. However, scant knowledge about the mechanism responsible for itching made treating it a riddle for modern medicine.

For centuries, scientists believed that itching was a weaker form of pain. Only in the late 1980s was it suggested that these are two completely separate sensations, travelling along different paths in the nervous system. It took another decade until the nerve responsible for itching was identified. And it was only in the summer of 2013 that a group of Harvard University and Hebrew University researchers published a groundbreaking article in the Nature Neuroscience journal, which showed that there are two independent itch circuits transmitting signals to the central nervous system.

The study was overseen by Dr. Alexander Binshtok of Hebrew University’s Edmond & Lily Safra Center for Brain Sciences, together with Prof. Clifford J. Woolf of Harvard University and doctoral students David Roberson (Hebrew University and Harvard University) and Sagi Gudes (Hebrew University). A new technique they developed could one day radically alter the lives of the estimated 15 percent of the population that suffers from severe and chronic itching.

In layman’s terms, what’s the new discovery?

Dr. Binshtok: “We were able to prove that itching is transmitted by its own neurons and not along with pain neurons. We also discovered that there are several distinct itch neurons, each responsible for a different type of itch – one resulting from the secretion of histamine, as happens with a mosquito bite, for instance; and another that’s caused by allergenic factors, such as inflammatory skin conditions like eczema and psoriasis, or as a side effect of drugs. Until now, it was customary to lump them all together. We were also able to block each of these types of itching separately, without affecting other physical sensations.”

Do doctors currently have anything to offer someone who suffers from itching?

“Doctors prescribe antihistamines, which have no effect on most itching sensations – because they are not caused by histamines. When antihistamines don’t help, or when the itching is very severe, the next step the doctor takes is to prescribe steroids. Steroid treatment is like the heavy artillery – it blasts everything and has a lot of side effects. It’s important to note that our research does not point to a treatment for the skin diseases themselves, but rather how to specifically neutralize the itch, which is a substantial part of the patient’s discomfort and which, without relief, leads to more serious illness.”

Recovery without painkillers

For some years, Binshtok has been causing a buzz in the scientific world. For example, a 2007 article he published in the prestigious journal Nature, proposing a new approach to anesthesia in invasive surgery, won wide-scale acclaim.

Anesthesia procedures have not changed substantially in the past 170 years. The first operation using a general anesthetic was performed at Massachusetts Hospital, Boston, in 1846, and ever since, the drugs used always work to suppress the nervous system. Therefore, general anesthesia is accompanied by loss of consciousness, during which the patient’s natural respiratory activity is halted. With local anesthesia, one specific area is paralyzed.

Binshtok proposed a way to block the sensation of pain by using two chemical substances – capsaicin (found in red chili pepper) and lidocaine (a local numbing agent). The unique combination of these two substances causes pain neurons to be blocked, but without blocking other cells. A similar method was used in the study of itching – and succeeded in blocking itch neurons without affecting other sensations, including pain.

What will surgery be like when this discovery is applied?

“If we can implement this solution with humans, it will mean that in the near future, people will be able to go in for something like dental surgery or childbirth, and come out without any side effects. Recovery will be painless. When a woman in labor is given an epidural injection, she can’t walk around; she has to lie down. With our treatment, she could do everything without feeling pain – walk around, push, even dance if she wants! Normal sensation and the ability to move without pain will also speed up the recovery and rehabilitation process following surgery and injuries, and improve the success rate of surgery.

“This is for minor surgery, but when we were writing the article, we were thinking that maybe this could point to a whole new way of anesthesia, one that would take general anesthesia out of use. One reason local anesthesia isn’t used for big operations is the concern that it will block the activity of the autonomic nervous system that controls the blood vessels and causes expansion of the blood vessels, blood pressure to drop and even death. We bypass all these things because we only neutralize the pain fibers.”

But won’t doctors prefer general anesthesia to complicated measures that immobilize the patient during surgery?

“We can also block movement during surgery by giving different concentrations of each drug we use. For example, we could block pain for 48 hours and movement for two hours. When it’s a long and complex operation, which the patient is fearful of undergoing while fully conscious, sedatives or sleep medication could also be used.”

It sounds like you’ve found a drug that will enable people to control pain as they see fit. Isn’t there a danger it could be abused?

“It’s not a drug, it’s not accompanied by a sense of euphoria. It could, however, potentially be used by competitive athletes. We once hosted a delegation from the Canadian army, and when they saw what we were working on, they immediately started thinking about creating the ultimate soldier. But that’s not the sort of application we’re thinking about in our research. We’re looking for a solution to acute, temporary pain.”

What about chronic pain?

“We’re trying to understand in the lab just how the system learns pain – how the connections between nerve cells change through stimuli. When you get a burn, the body knows to alter the neural wiring so that touch is interpreted as pain. Normally, once the cells are repaired, the body is able to return to the status quo, but sometimes it learns the change but is unable to forget it, and then it becomes a symptom of disease – chronic pain, which is a type of faulty learning by the brain. We recently published an article in the journal Nature Methods, about a novel technique that makes it possible to better study the complex structure of the neural circuits in the central nervous system. We’re hoping to achieve further insights in this area, too.”

How far are your two methods from being practically implemented?

“Right now we’re at the testing stage of examining the toxicity of giving the substances together, and I think it will be several years until we’re ready for human trials. However, a colleague of mine in Germany, where the rules are a little different, is already thinking of starting human trials in the coming months – and this could prove a catalyst. The patent itself belongs to Harvard, where I wrote the original research as part of my postdoctoral work.”

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