Chronic pain affects over 100 million people in the U.S. alone. Treatments remain ineffective for these devastating conditions, in large part because the underlying causes that lead to chronic pain are not well understood. The NIH Common Fund Acute to Chronic Pain Signatures (A2CPS) study is a bold research initiative that aims to identify markers that help predict whether someone is more or less likely to develop chronic pain after surgery. Now, A2CPS has published a paper in the journal PAIN that reviews what we already know about potential markers of chronic pain and provides an overview of the ongoing A2CPS study to expand on that knowledge.

Biomarkers, which are molecules measured in blood, other body fluids, or tissues that can tell researchers what is going on in someone’s body, are commonly used to diagnose, predict, or treat diseases. Researchers have identified biomarkers for diseases including diabetes, heart disease, and some cancers. While no biomarkers have been scientifically validated to indicate pain, some potential biomarkers have been identified in previously published reports. In the new paper, the A2CPS Consortium presents a review of these candidate biomarkers and outlines how A2CPS will examine them as well as other novel markers to predict risk of chronic postsurgical pain. 

The A2CPS research initiative will follow approximately 2,800 participants for six months after knee replacement or thoracic surgery, collecting biological and brain imaging data and performing physical tests and psychological and social assessments. As outlined in their protocol paper, the A2CPS team is doing testing and taking blood samples and brain images of participants. They are also capturing participant-reported pain outcomes. From these data, the A2CPS team will look for differences in biomarkers observed between people who transition from acute to chronic pain and those who do not, which could reveal biomarkers associated with this change. The A2CPS Consortium will also make de-identified data publicly available to other researchers for further study. The findings will help researchers better understand the complex biological processes underlying chronic pain, which may lead to better, more individualized treatments for patients.