Granulation encapsulated stent: a new therapeutic approach for vascular implantation.
OBJECTIVE
To determine if stents could be encapsulated with immunocompatible granulation tissue for the treatment of vascular diseases.


METHODS
Bare metal stents were implanted in New Zealand white rabbits so they would be encapsulated with immunocompatible granulation tissue. The granulation encapsulated stents (GES) were then treated with either mitomycin C or saline, and implanted into rabbit iliac arteries for 4 weeks. To test whether the effect of mitomycin C was retained, we co-cultured smooth muscle cells for 3 h with subcutaneous tissue (as control) or with granulation tissue from GES treated with mitomycin C and saline.


RESULTS
Vessels with GES treated with mitomycin C (MS) and washed with saline had significantly less neointimal area (NA) after 4 weeks (0.27 (SD 0.03) mm(2) than vessels containing bare metal stents (B) (1.15 (SD 0.10) mm(2), n = 5, p<0.05) or GES treated with saline (S) (4.78 (SD 0.72) mm(2), n = 5, p<0.05). The average vessel injury score was not significantly different among these three groups (S: 1.98 (SD 0.51), MS: 1.46 (SD 0.18) and B: 1.51 (SD 0.32)). GES treated with saline had significantly less NA than the other two groups and also blocked blood flow in the contralateral iliac artery in the abdominal aortic bifurcation immediately after implantation and 4 weeks later. Histology also showed neointimal overgrowth in the vessel wall over the contralateral iliac artery.


CONCLUSIONS
GES treated with mitomycin C can significantly inhibit neointimal formation in rabbit arteries due to the formation of granulation tissue. GES treated with saline demonstrated significantly increased NA and resisted normal rabbit artery pressures.
Tang
Lilong
L
Division of Cardiology, The Fifth Affiliated Hospital to Sun Yat-Sen University, Meihua Dong Road 52, Zhuhai, Guangdong, China. lilong_tang@163.com
Chen
Xiaochao
X
Tang
Shuangbo
S
LaLonde
Thomas
T
Gardin
Julius M
JM
D000818:Animals; D019917:Blood Vessel Prosthesis Implantation / Q000379:methods*; D023903:Coronary Restenosis / Q000517:prevention & control*; D006097:Granulation Tissue / Q000187:drug effects* / Q000637:transplantation; D015745:Granuloma, Foreign-Body / Q000209:etiology; D007083:Iliac Artery / Q000473:pathology / Q000601:surgery*; D016685:Mitomycin / Q000494:pharmacology; D023421:Models, Animal; D009131:Muscle, Smooth, Vascular / Q000473:pathology; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D011817:Rabbits; D015607:Stents / Q000009:adverse effects; D046509:Tissue Culture Techniques; D017539:Tunica Intima / Q000473:pathology*
D019384:Nucleic Acid Synthesis Inhibitors; D016685:Mitomycin