Methotrexate improves endothelial function in early rheumatoid arthritis patients after 3 months of treatment

BACKGROUND: Endothelial dysfunction contributes to increased cardiovascular (CV) disease in rheumatoid arthritis (RA). Angiogenic T cells (Tang) are a key regulator of vascular function via their interaction with endothelial progenitor cells (EPCs). Methotrexate (MTX) has been associated to reduced CV disease risk, but its effects on endothelial homeostasis have been poorly explored. We investigated MTX effects on endothelial homeostasis in early, treatment-naïve RA patients. METHODS: Fifteen untreated, early RA patients and matched healthy controls (HC) were enrolled. RA patients with long-standing disease in remission or low disease activity treated with MTX for at least 6 months were selected as controls. Circulating CD28(+) and CD28(null) Tang cell, endothelial microparticle (EMP), EPC and soluble vascular cell adhesion molecule (sVCAM)-1 levels were measured. RESULTS: Tang percentage was higher in early RA than in HCs and significantly increased after 3-month MTX treatment. Tang cells in RA were characterized by higher percentage of CD28(null) and lower CD28-positive cells than HCs. MTX restored a Tang cell phenotype similar to HCs. Altered sVCAM-1, EMP and EPC were restored to levels similar to HCs after a 3-month MTX. Biomarker levels after 3 months of MTX were not different to those of patients with long-standing treatment. CONCLUSIONS: MTX has a positive effect on Tang, sVCAM-1, EPCs and EMPs in RA. Restoration of imbalance between CD28 + and CD28(null) Tang by MTX may be one of the mechanisms underlying its favourable effects on endothelial dysfunction. These effects seem to be long-lasting and independent from systemic inflammation reduction, suggesting a direct effect of MTX on the endothelium.