Circulating PAMM, a novel antioxidant and anti-inflammatory protein, is elevated in acute SCI

Background: Peroxiredoxin activated in M-CSF stimulated monocytes (PAMM) is a novel protein produced by adipocytes with putative redox regulatory and anti-inflammatory properties. Because acute spinal cord injury (SCI) is associated with oxidative stress and neuroinflammation and because PAMM can be detected in systemic circulation, we hypothesized that acute neuro-trauma might induce changes in circulating PAMM expression. Specifically, we hypothesized that PAMM levels might vary based on the presence or absence of acute, traumatic SCI. We therefore investigated circulating PAMM levels in adults with and without acute traumatic SCI. Methods: We studied 105 men and women (54 with SCI and 51 without SCI). Participants with SCI were admitted for acute rehabilitation within 1 month after injury. Serum samples were obtained during hospitalization and stored at-80 °C until batch analysis. Total PAMM was quantified by ELISA assay (MyBiosource, Cat. No: MBS9327247) with a detection limit of 0.25 ng/ml. Separate multivariate models including age, BMI, and injury severity were assessed to determine significant clinical predictors of change in PAMM levels. Results: When adjusting for BMI, age, and gender, mean change in PAMM levels were greatest in participants with motor complete SCI compared to able-bodied (1.65 ng/ml versus 0.94 ng/ml, p = 0.003). This model explained 26% of the variation in change in circulating PAMM levels. Conclusions: Our results suggest that PAMM may be a novel biomarker of neurological injury or of native anti-inflammatory responses to neurological injury. More work is needed to establish the role of PAMM and other adipocyte-derived factors in the acute response to neurotrauma.