Research Paper Volume 11, Issue 19 pp 8604—8622

Tryptophan metabolite 5-methoxytryptophan ameliorates arterial denudation-induced intimal hyperplasia via opposing effects on vascular endothelial and smooth muscle cells

Figure 6. 5-MTP decreases VSMC proliferation following arterial injury. (AC) Femoral arteries were harvested 2 weeks after injury. Arterial sections were immunostained with BrdU antibody (brown) to detect proliferating cells. Arrowhead indicates endothelium (end) and arrows indicate BrdU-positive brown nuclei. adv, adventitia; med, media; neo, neointima. (D) BrdU-positive cells were quantified and expressed as % of total cells in the neointima or media. 5-MTP decreased BrdU incorporation in the neointima (n=10 each; *p<0.002) and in the media (n=10 each; #p<0.02). (E) Serum-starved VSMCs were treated with TNF-α for 24 h, proliferation was then measured and normalized to control without TNF-α (n=3, *p<0.01 vs. control). (F) Serum-starved VSMCs in the presence of vehicle or 5-MTP were treated with TNF-α for 24 h, proliferation was then measured and normalized. TNF-α increased VSMC proliferation (n=3 each, *p<0.02). 5-MTP mitigated TNF-α-induced proliferation (n=3 each, *p=0.05). (G) VSMCs were treated as in (F), stimulated without or with different concentrations of angiotensin II (AngII) for 24 h. Cell proliferation was then measured as in (F). n=3 each, *p<0.005. (H) VSMCs were treated as in (F), stimulated with or without TNF-α for 24 h, and then transwell migration assays performed. Cells migrated through membranes were quantified after 4 h. The migrated cell number of vehicle control without TNF-α treatment and without PDGF-BB as a chemoattractant was set as 1. 5-MTP had no effect on migration under this condition. TNF-α increased VSMC migration (n=3, *p<0.002) while 5-MTP decreased TNF-α-induced migration (n=3, #p=0.001). ns, no significance.