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.

Latest News

A2CPS Journal Club with Kimberly Sibille, PhD

Published November 2023

Please join A2CPS for our next Journal Club Thurs Dec 7 at noon ET. Kimberly Sibille, PhD, of the University of Florida, will present Whole Person Biomarkers: Elucidating Individual Differences in Chronic Pain, recently published in Brain, Behavior and Immunity with Angela Mickle, PhD, and Jared Tanner, PhD. Register here for free. 

A2CPS Journal Club with Stephan Frangakis, MD, PhD

Published Oct 2023

Please join us for Journal Club featuring Stephan Frangakis, MD, PhD, of the University of Michigan on Thursday, Oct 19 at 2 pm ET. Dr. Frangakis's talk is Genetic Associations with Postsurgical Pain, following his recent publication in Anesthesiology. This event is free and open to the public with registration.