Short-term salicylate treatment improves microvascular endotheliumdependent dilation in young adults with major depressive disorder

Reactive oxygen species (ROS)-mediated reductions in nitric oxide (NO)-dependent dilation are evident in adults with major depressive disorder (MDD); however, the upstream mechanisms remain unclear. Here, we hypothesized that nuclear factor-κB (NF-κB) activation-induced ROS production contributes to microvascular endothelial dysfunction in MDD. Thirteen treatment-naive adults with MDD (6 women; 19-23 yr) and 10 healthy nondepressed adults (HAs; 5 women; 20-25 yr) were tested before and after (open-label design) systemic NF-κB knockdown (nonacetylated salicylate; 3,000-4,500 mg/day x 4 days). Red cell flux (laser Doppler flowmetry) was measured during graded intradermal microdialysis perfusion of the endothelium-dependent agonist acetylcholine (ACh), alone and in combination with NO synthase inhibition [NG-nitro-L-arginine methyl ester (L-NAME)] or ROS scavenging (apocynin). Serum salicylate concentrations following treatment were not different between groups (22.8 ± 7.4 HAs vs. 20.8 ± 4.3 mg/dL MDD; P = 0.46). When compared with HAs, the NO-dependent component of ACh-induced dilation was blunted in adults with MDD before (P = 0.023), but not after (P = 0.27), salsalate treatment. In adults with MDD, the magnitude of improvement in endothelium-dependent dilation following salsalate treatment was inversely related to the degree of functional impairment at baseline (R2 = 0.43; P = 0.025). Localized ROS scavenging improved NO-dependent dilation before (P < 0.01), but not after (P > 0.05), salsalate treatment. Salsalate did not alter systemic concentrations of pro- or anti-inflammatory cytokines (all P > 0.05). These data suggest that NF-κB activation, via increased vascular ROS production, contributes to blunted NO-dependent dilation in young adults with MDD but otherwise free of clinical disease. These data provide the first direct evidence for a mechanistic role of vascular inflammation-associated endothelial dysfunction in human depression.