Artwork by Kathleen Sluka

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


The Value of an Open-Science Ecosystem

Published March 2025

A2CPS Principal Investigator Martin Lindquist of Johns Hopkins University authored a paper published in Pain Medicine that argues for the critical importance of open science ecosystems using the NIH HEAL Initiative® as a case study.


A2CPS Releases Data for Analysis

Published January 2025

The A2CPS Cosortium announces the first public release of data for further use and analysis by researchers via the NIMH Data Archive (NDA). Learn more at our For Researchers pages and in this preprint on BioRxivs: Image Processing in the Acute to Chronic Pain Signatures (A2CPS) Project