How does the autologous internal rectus fascia sheath vascular graft react upon different vasoactive substances? Experimental myographic examination in a dog model

The tubular vascular conduit graft made from the internal rectus fascia sheath is a possible alternative technique for vessel replacement in vascular surgery. Based on previous histomorphological examinations, the structure of rectus sheath changes after the implantation and the graft becomes morphologically similar to the intact vessel with endothel cell monolayer on the inner surface and myofibroblast cells in the thick collagen rich wall, but it does not contain a proper smooth muscle cell layer as in an intact vessel. In physiological circumstances the vessels react with contraction and relaxation upon different vasoactive substances, accommodating to the needs of the body. This behavior can be examined experimentally by recording the isometric tension in a myographical chamber. We have performed our experimental measurements three month after the graft implantation. The results show that the graft reacted upon the effect of the 124mM K+, the phenylephrin and the acetyl-cholin similary to the control artery, but this reaction was much weaker. Interestingly, the reaction upon the thromboxan A(2) agonist U-46619 was stronger in the graft than in the control artery.