Science and Medicine

People with minor variations in a newly discovered gene showed clear differences in susceptibility to acute heat pain and chronic back pain.

While it has become clear in recent years that susceptibility to pain has a strong inherited component, very little is known about actual “pain genes” and how they work. In the November 12th issue of Cell, researchers at Children’s Hospital Boston and their collaborators report on a novel human pain gene. People with minor variations in this gene showed clear differences in susceptibility to acute heat pain and chronic back pain. Corroborating mouse studies give some clues as to how the gene controls pain sensitivity. The gene was uncovered in a genome-wide hunt for pain genes in fruit flies, which revealed hundreds of other candidate pain genes that await further study.

Understanding the genetic basis of pain will lead to the development of new analgesics, the identification of risk factors for chronic pain and improved decision-making about the suitability of surgical treatment for different patients, says Clifford Woolf, MB, BCh, PhD, the study’s senior co-author and director of the F.M. Kirby Center and Program in Neurobiology at Children’s.

Classic studies of twins indicate that about 50 percent of variance in pain sensitivity is inherited.

“Across a number of different kinds of pain, genes seem to be at least half the driver of how much pain you experience,” Woolf said. “Genes give us an amazing and powerful tool to begin to understand how pain is generated, and which functional pathways and specific proteins are involved.”

Read more: Pain Gene Common to Flies, Mice and Humans

Popcorn popped in a microwave. PAPs are applied as greaseproofing agents to paper food contact packaging such as fast food wrappers and microwave popcorn bags.

University of Toronto scientists have found that chemicals used to line junk food wrappers and microwave popcorn bags are migrating into food and being ingested by people where they are contributing to chemical contamination observed in blood.

Perfluorinated carboxylic acids or PFCAs are the breakdown products of chemicals used to make nonstick and water- and stain-repellent products ranging from kitchen pans to clothing to food packaging. PFCAs, the best known of which is perfluorooctanoic acid (PFOA), are found in humans all around the world.

“We suspected that a major source of human PFCA exposure may be the consumption and metabolism of polyfluoroalkyl phosphate esters or PAPs,” says Jessica D’eon, a graduate student in the University of Toronto’s Department of Chemistry. “PAPs are applied as greaseproofing agents to paper food contact packaging such as fast food wrappers and microwave popcorn bags.”

In the U of T study, rats were exposed to PAPs either orally or by injection and monitored for a three-week period to track the concentrations of the PAPs and PFCA metabolites, including PFOA, in their blood. Human exposure to PAPs had already been established by the scientists in a previous study. Researchers used the PAP concentrations previously observed in human blood together with the PAP and PFCA concentrations observed in the rats to calculate human PFOA exposure from PAP metabolism.

Read more: Dangerous Chemicals in Food Wrappers Likely Migrating to Humans