Spider venom suggests pain solution for IBS
SPIDER venom could form the basis of a new treatment for the pain associated with irritable bowel syndrome, says new research published in Nature. Irritable bowel syndrome (IBS) is a functional gastrointestinal (GI) disorder. If a person has a functional disorder, they experience symptoms, but diagnostic tests do not reveal any structural or biochemical abnormalities.
Doctors do not know what causes IBS, but emotional factors, medication, diet, and hormones may trigger or worsen the symptoms. Fatty food and stress may provoke it. According to the International Foundation for Functional Gastrointestinal Disorders (IFFGD), around 10-15 percent of people experience IBS worldwide. Not everyone who has IBS consults a doctor, but it is one of the most common disorders seen by physicians. In the United States, between 2.4-3.5 million visits per year are thought to be due to IBS. It accounts for up to 12 percent of all primary care consultations.
Between 60-65 percent of cases involve women, and it is thought that some women with IBS undergo unnecessary abdominal surgery in an attempt to end the problem. In the current study, an international team of researchers, from the U.S. and Australia, used spider venom to pinpoint a protein that is involved in transmitting the type of pain felt by people with IBS.
The study was led jointly by Associate Prof. Stuart Brierley, of the University of Adelaide, and Prof. Glenn King, from the University of Queensland - both in Australia - as well as Prof. David Julius, from the University of California-San Francisco, and Dr. Frank Bosmans, from Johns Hopkins University in Baltimore, MD.
The team investigated 109 spider, scorpion, and centipede venoms. The strongest result was from the venom of a type of tarantula found in West Africa, known as Heteroscodra maculate. The venom was found to activate an ion channel, or a protein in nerves and muscles, known as NaV1.1, which also plays a role in epilepsy.
The first finding of the current study was that NaV1.1 could be important in sensing and transmitting pain. The team then found that NaV1.1 was present in pain-sensing nerves in the intestines, suggesting that the pathological levels of abdominal pain experienced by people with IBS could stem from NaV1.1. The authors believe that identifying NaV1.1’s role in signalling chronic pain is the first step toward creating new treatments.
Prof. King notes that spider venom is useful for investigating the processes of pain signalling in humans. “Spiders make toxins to kill prey and defend themselves against predators, and the most effective way to defend against a predator is to make them feel excruciating pain,” he says. Because of this, he explains, we can expect spider venom to be full of molecules that stimulate the pain-sensing nerves in the body.