Up to 50% of saphenous vein (SV) grafts will be occluded ten years after a coronary bypass operation, compared to only 2-5% of the mammary (IMA) or radial (RA) artery grafts. The superior patency of the arterial graft translates into improved long-term survival and freedom from cardiac-related adverse events. SV graft occlusion after bypass surgery is primarily related to accelerated graft atherosclerosis. The superiority of arterial grafts compared to SVs has been attributed to their striking resistance to atherosclerosis. In this study, we evaluated one of the primary protective cellular mechanisms against oxidative stress and atherosclerosis, Thioredoxin-1 (Trx-1) in arterial and venous conduits.
The expression of Trx-1 in IMA and RA was similar and significantly higher compared to SV. These data suggest that arterial conduits express significantly higher amounts of Trx-1 compared to saphenous veins, possibly rendering them more resilient to oxidative stress and accelerated graft atherosclerosis.
Figure 1: Differential Trx expression between conduits. (A) Protein extracts from patient conduit tissue was prepared and immunoblot analysis was performed using anti-Trx. Trx band were quantified and normalized to the corresponding beta actin. Average from all the patients is shown. Statistical signficance is indicated in the figure. NS= not significant. Number of patients is indicated for each column.