Perigraft vascularization and incorporation of implanted Dacron prostheses are affected by rifampicin coating

Abstract

Prosthetic vascular grafts are increasingly implanted to replace damaged arteries. However, their microbial contamination is highly problematic and often results in devastating clinical complications. To reduce the risk of infection, Dacron grafts may be coated with rifampicin. In this experimental study we analyzed whether this coating affects the early tissue incorporation of the grafts. Saline- and rifampicin-coated Dacron (Dacron-Rifamp) grafts were implanted into dorsal skinfold chambers of C57BL/6 mice (n= 8 per group) to study vascularization, inflammation, cell proliferation, and apoptosis at the implantation site using repetitive intravital fluorescence microscopy and immunohistochemistry over an observation period of 14days. Implanted Dacron-Rifamp grafts exhibited a impaired vascularization, indicated by a significantly lower functional capillary density (85± 1cm/cm2) compared with controls (113± 1cm/cm2; P< .05). This was associated with a reduced number of Ki-67-positive proliferating cells (9.4%± 1.1% vs 13.5± 0.4%; P< .05) and an increased number of cleaved caspase-3-positive apoptotic cells (2.7%± 0.3% vs 1.3%± 0.3%; P< .05) in the newly developing granulation tissue surrounding the implants. In addition, the neutrophilic (652± 84mm2 vs 934± 117mm2; P= .06), lymphatic (26± 6mm2 vs 39± 9mm2; P= .24) and macrophage response (177± 42mm2 vs 233± 86mm2; P= .57) was decreased by trend in the group with Dacron-Rifamp grafts. Our novel findings show that early perigraft vascularization and incorporation of implanted Dacron prostheses are affected by the rifampicin coating. Because rapid graft vascularization and incorporation are thought to reduce the risk of infection, the use of Dacron-Rifamp Dacron grafts for antibacterial prophylaxis should be reconsidered particularly in cases of elective arterial reconstruction in a noninfected environment.