
<ArticleTitle>Adenovirus-mediated gene transfer of human <prot>inducible nitric oxide synthase</prot> in porcine vein grafts inhibits intimal hyperplasia.</ArticleTitle>
<AbstractText>OBJECTIVE: The aim of this study is to determine whether adenoviral <prot>inducible nitric oxide synthase</prot> (<prot>iNOS</prot>) gene transfer could inhibit intimal hyperplasia (IH) in porcine internal jugular veins interposed into the carotid artery circulation. METHODS: Porcine internal jugular veins were transduced passively with 1 x 10(11) particles of an adenoviral vector carrying either the human <prot>iNOS</prot> (<prot>AdiNOS</prot>) or <prot>beta-galactosidase</prot> (<prot>AdlacZ</prot>) cDNA for 30 minutes and then interposed into the carotid artery circulation. Segments of each vein graft were maintained in an ex vivo organ culture to measure nitrite accumulation, a marker of nitric oxide synthesis. The grafts were analyzed immunohistochemically for the presence of neutrophils, macrophages, and leukocytes by staining for <prot>myeloperoxidase</prot>, <prot>ED1</prot>, and <prot>CD45</prot>, respectively, at 3 (n = 4) and 7 (n = 4) days. Morphometric analyses and cellular proliferation (Ki67 staining) were assessed at 3 (n = 4), 7 (n = 4), and 21 days (n = 8). RESULTS: <prot>AdlacZ</prot>-treated vein grafts demonstrated high levels of <prot>beta-galactosidase</prot> expression at 3 days with a gradual decline thereafter. Nitrite production from <prot>AdiNOS</prot>-treated vein grafts was approximately fivefold greater than <prot>AdlacZ</prot>-treated grafts (P =.00001). <prot>AdiNOS</prot> or <prot>AdlacZ</prot> treatment was associated with minimal graft inflammation. Cellular proliferation rates were significantly reduced in <prot>AdiNOS</prot>-treated grafts as compared with controls at both 3 (41%, P =.000004) and 7 days (32%, P =.0001) after bypass. This early antiproliferative effect was most pronounced at the distal anastomosis (65%, P =.0005). The <prot>iNOS</prot> gene transfer reduced the intimal/medial area ratio in vein grafts at 7 (36%, P =.009) and 21 days (30%, P =.007) versus controls. This inhibition of IH was again more prominent in the distal segments of the grafts (P =.01). CONCLUSION: Adenovirus-mediated <prot>iNOS</prot> gene transfer to porcine internal jugular vein grafts effectively reduced cellular proliferation and IH. Although <prot>iNOS</prot> gene transfer reduced IH throughout the entire vein graft, the most pronounced effect was measured at the distal anastomosis. These results suggest potential for <prot>iNOS</prot>-based genetic modification of vein grafts to prolong graft patency.</AbstractText>
