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
Patrick Sadil, PhD, promoted at Johns Hopkins
Published Sep 2026
Patrick Sadil, PhD, was appointed to Assistant Scientist in the Biostatistics Department at the Bloomberg School of Public Health, Johns Hopkins University. Patrick is a data scientist with deep expertise in neuroimaging and computational abilities. He's an integral part of the A2CPS team, where he has has been working with Martin LIndquist to lead development and curation of the neuroimaging pipelines. Congratulations, Patrick!
Online Workshop: Explore the A2CPS Dataset
Published Sep 2026
The A2CPS multimodal dataset contains massive opportunities for analysis and study in pain research and beyond. Come learn what types of data are included and how to best access them: brain imaging, functional testing, patient-reported pain outcomes, multi-omics, quantitative sensory testing. Tuesday, September 29 at 10 PT/ 1 ET. Register for free: https://painresearchers.com/topics/22512/events/287146
