For most people, pain goes away when an injury heals. But for some people, pain after surgery can linger, and can last for years or even a lifetime. The Acute to Chronic Pain Signatures (A2CPS) project is a bold research initiative - the largest and most comprehensive of its kind - being carried out by a nation-wide consortium of researchers. The findings will help researchers to develop better, more individualized treatments for patients and to better understand the complex biological processes underlying chronic pain.
About A2CPS
Protocol
A2CPS will collect questionnaires, blood samples and brain imaging from 2,800 participants before and for up to 12 months after having total knee replacement or thoracic surgery.
Biomarkers
Many diseases can be diagnosed, tracked and predicted with biological markers, or biomarkers, but none are yet known for chronic pain. The major aim of A2CPS is to find biomarkers or bio-signatures of the transition to chronic pain.
Consortium
The A2CPS consortium is organized into four main hubs, with over 100 investigators and staff around the country. Our researchers span a wide range of expertise, from basic scientists to clinicians to data management experts.
Assessments
In addition to biological specimens, A2CPS also collects different types of data from our participants, including patient-reported outcomes (PROs) and quantitative sensory testing (QST), among others.
Omics from Blood
The term “omics” refers to the collection of information about the molecules found in our blood, which can tell us about the activity of genes, proteins, lipids and metabolites in our cells and tissues.
Brain Imaging
Previous studies have identified “signatures” of brain activity that reflect a painful experience, and others that predicted who was more likely to develop chronic pain. A2CPS will include brain-imaging data in our search for biosignatures of chronic pain.
Did you know?
A2CPS now ranks #9 among the largest brain-imaging studies undertaken to date!
See how A2CPS compares
Latest News
Webinar offers guidance on NIH HEAL pain research funding
Published May 2026
The PURPOSE network offered a webinar for pain researchers, "Navigating Pain Funding Pathways with the NIH Heal Initiative: From Ideas to Impact," hosted by Michael Oshinsky, PhD, Director of the NINDS Office of Preclinical Pain Research. The recording is available here. If you're not a member of the PURPOSE network, join today for free!
The NIH Common Fund Data Ecosystem
Published April 2026
A2CPS investigators Ari Kahn (pictured), Martin Lindquist and James Carson co-authored a preprint describing the NIH's Common Fund Data Ecosystem (CFDE), now available on BioRxiv. The CFDE integrates data resources from 18 NIH Common Fund programs for discovery and integrative analysis and aims to provide a collaborative, community-built infrastructure.
