Transient receptor potential channels as blood biomarkers for pain characteristics in patients with chronic pain

Transient receptor potential (TRP) channels play key roles for the transition from acute to chronic postoperative pain after surgery. To evaluate TRP channels in the peripheral blood cells as blood biomarkers for chronic pain, we collected blood samples for genome-wide assays of the mRNA expression and assessed pain intensity and the number of pain symptoms in 13 patients with chronic pain. There was a significant association between increases in the number of pain symptoms and increases in the TRP vanilloid 1 (TRPV1) expression. Decreases in the TRP ankyrin 1 (TRPA1) expression, however, tended to increase the number of pain symptoms. There was likely an inverse relationship for TRPV1 and TRPA1 expressions with regard to the number of pain symptoms in chronic pain patients.