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.


San Diego Pain Summit

Published January 2023

The San Diego Pain Summit is a multidisciplinary pain management conference to help clinicians translate pain research into clinical practice. Join a diverse group of pain researchers, clincians and patients in beautiful San Diego, California February 14 - 19, 2023 at The Dana at Mission Bay. On Sat Feb 18 at 9 am, A2CPS Principal Investigator Kathleen Sluka, PT, PhD, FAPTA, will deliver the Keynote address: “The Science of Exercise for Pain Control: Mechanisms and Clinical Implications.” Register here!

Funding Opportunity from the NIH Common Fund

Published January 2023

Several valuable and widely available data sets have been generated by multiple Common Fund programs. The purpose of this funding opportunity announcement (FOA) is to announce the availability of funding to demonstrate and enhance the utility of selected Common Fund ( data sets, including generating hypotheses and catalyzing discoveries. Award recipients are asked to provide feedback on the utility of the Common Fund data resources. Deadline is February 3, 2023. 


A2CPS Journal Club with Dr. Hance Clarke

Published January 2023

Join A2CPS for our first Journal Club of 2023.  Thursday, Jan 26 at noon ET, Dr. Hance Clarke, MD, PhD, FRCPC, will discuss his work examining the various pain trajectories that patients take after surgery. The talk is titled "Improving Perioperative Care: Identifying and Intervening Early in HIgh Risk Patients." This event is free and open to the public; click here to register. This event will also be recorded and available in our Vimeo library. Dr. Clarke will discuss work published in two papers: Faschler et al., 2022  in the Journal of Pain Research, and Page et al., 2015 in PAIN.  

A2CPS Investigator Dr. Joe Zhou named Fellow by American Association of Physicists in Medicine 

Published November 2022

Congratulations to Dr. Xiaohong Joe Zhou, PhD, DABR, DABMP, who was recently named a Fellow by the American Association of Physicists in Medicine (AAPM). Dr. Zhou currently serves as a professor of radiology, neurosurgery and biomedical engineering at the University of Illinois at Chicago and Chief Medical Physicist at UI Health. At A2CPS, Dr. Zhou plays a pivotal role in collecting and analyzing our brain imaging data, one of many types of biomarkers we are investigating.