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Updated: Dec 13, 2025

Chronic Post-Ischemia Pain Model for Complex Regional Pain Syndrome Type-I in Rats
Published on: January 21, 2020
Novel immune biomarkers in complex regional pain syndrome
Marc A Russo1, Peter Georgius2, Ananda Staats Pires3
1Hunter Pain Specialists, 91 Chatham Street, Broadmeadow, NSW, 2292, Australia; Genesis Research Services, 220 Denison St, Broadmeadow, NSW, 2292, Australia.
Abstract:
We investigated serum levels of 29 cytokines and immune-activated kynurenine and tetrahydrobiopterin pathway metabolites in 15 complex regional pain syndrome (CRPS) subjects and 14 healthy controls. Significant reductions in interleukin-37 and tryptophan were found in CRPS subjects, along with positive correlations between kynurenine/tryptophan ratio and TNF-α levels with kinesiophobia, tetrahydrobiopterin levels with McGill pain score, sRAGE, and xanthurenic acid and neopterin levels with depression, anxiety and stress scores. Using machine learning, we identified a set of binary variables, including IL-37 and GM-CSF, capable of distinguishing controls from established CRPS subjects. These results suggest possible involvement of various inflammatory markers in CRPS pathogenesis.

