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


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.


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.


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.


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.


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.


NIH 18th Annual Pain Consortium Symposium

Published May 2023

On June 6th - 7th, the NIH Pain Consortium will convene the 18th Annual Pain Consortium Symposium on Advances in Pain Research: Resilience and Pathways to Recovery in Bethesda, MD. Keynote speaker will be Afton Hasset, PsyD, of University of Michigan. Free registration (including virtual access) and more information available here

1st Annual PURPOSE Meeting

Published April 2023

Have you joined the new PURPOSE network yet? It's the NIH HEAL Initiative's Coordinating Center for National Pain Scientists (CCNPS). PURPOSE stands for "Positively Uniting Researchers of Pain to Opine, Synthesize, & Engage." Join them for their first meeting at the National Harbor in Maryland May 11 - 13, in person or virtually. Register now for membership in PURPOSE to join the meeting. 

2023 Society for Clinical Trials Meeting 

Published April 2023

Join A2CPS Investigators at the 44th annual meeting of the Society for Clinical Trials (SCT) in Baltimore May 21 - 24. Dixie Ecklund of A2CPS's Clinical Coordinating Center at the University of Iowa chairs a session titled “Increasing Demographic Representation of Participants in NIH HEAL-funded studies: Experiences from the Acute to Chronic Pain Signatures (A2CPS) Program." Presenters include A2CPS members Laura Wandner, PhD (NIH) and Giovanni Berardi, PhD (U Iowa). Register now. 


A2CPS Journal Club April 27

Published March 2023

Join A2CPS for our next Journal Club featuring Eva Kosek, MD, PhD, of the Karolinska Institute in Sweden on Thursday April 27 at noon ET. The title of Professor Kosek's talk is "Neuroimmune Signatures and Interactions in Chronic Pain." This event is open to members of the public; please register here