ICAM-1 and VCAM-1 antisense oligonucleotides attenuate in vivo leucocyte adherence and inflammation in rat inflammatory bowel disease.

BACKGROUND: Recruitment of circulating cells to the inflamed intestine is modulated by adhesion molecules expressed on the surface of both leucocytes and endothelial cells. AIMS: The objective of this study was to test whether 2'-O-methoxyethyl chimeric antisense oligonucleotides directed against endothelial intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) can downregulate leucocyte-endothelial interactions and thereby attenuate inflammation in rat experimental ileitis. METHODS: Indomethacin (7.5 mg/kg ) was injected subcutaneously into Sprague-Dawley rats 48 and 24 hours prior to intravital microscopy. Animals were treated with either ICAM-1 (ISIS 17470), VCAM-1 (ISIS 18155), or scrambled control antisense oligonucleotides administered subcutaneously or intravenously in parallel with indomethacin. Leucocyte trafficking was observed in ileal submucosal collecting venules. Macroscopic and histological grades of inflammation were measured 48 hours after the first indomethacin application. ICAM-1 and VCAM-1 expression in ileal submucosal venules was detected by immunohistochemistry. RESULTS: Intravenous administration of ICAM-1 oligonucleotides 2 mg/kg (rolling leucocytes 5.7 (2.4)/0.01 mm(2) endothelial surface, adherent leucocytes 0.8 (1.1)) and VCAM-1 oligonucleotides 8 mg/kg (9.2 (4.4), 0.6 (0.8)) significantly reduced leucocyte adhesion compared with diseased controls (27.8 (5.3), 14 (4.4)) in a dose dependent manner whereas subcutaneous treatment did not. Correspondingly, macroscopic and histological inflammation was significantly decreased. ICAM-1 oligonucleotides markedly reduced endothelial ICAM-1 expression while VCAM-1 oligonucleotides clearly diminished endothelial VCAM-1 expression. CONCLUSIONS: Both ICAM-1 and VCAM-1 2'-O-methoxyethyl chimeric antisense oligonucleotides attenuate rat ileitis by downregulation of leucocyte adherence and thus are potential candidates for anti-inflammatory treatment in inflammatory bowel disease.

Regulation of murine intestinal inflammation by reactive metabolites of oxygen and nitrogen: divergent roles of superoxide and nitric oxide.

Several reports have implicated reactive oxygen and nitrogen metabolites (RONS) in the initiation and/or progression of inflammatory bowel diseases (IBDs). We have investigated the role of three key RONS-metabolizing enzymes (inducible nitric oxide synthase [iNOS], superoxide dismutase [SOD], nicotinamide adenine dinucleotide phosphate [NADPH] oxidase) in a murine model of IBD. Mice genetically deficient ((-/-)) in either iNOS or the p47phox subunit of NADPH oxidase, transgenic (Tg) mice that overexpress SOD, and their respective wild-type (WT) littermates were fed dextran sulfate sodium (DSS) in drinking water for 7 days to induce colitis. In addition, the specific iNOS inhibitor 1400W was used in DSS-treated WT and p47phox(-/-) mice. WT mice responded to DSS feeding with progressive weight loss, bloody stools, elevated serum NO(X) and colonic mucosal injury with neutrophil infiltration. Both the onset and severity of colitis were significantly attenuated in iNOS(-/-) and 1400W-treated WT mice. While the responses to DSS did not differ between WT and p47phox(-/-) mice, enhanced protection was noted in 1400W-treated p47phox(-/-) mice. Interestingly, SOD(Tg) mice exhibited more severe colitis than their WT littermates. These findings reveal divergent roles for superoxide and iNOS-derived NO in intestinal inflammation.

Role of intercellular adhesion molecule 1 in indomethacin-induced ileitis.

Adhesion molecules have been implicated in the pathogenesis of inflammatory bowel diseases. We investigated their expression and contribution to leukocyte recruitment in experimental intestinal inflammation. Ileitis was induced in Sprague-Dawley rats by two injections of indomethacin (7.5 mg/kg), given 24 h apart. Endothelial intercellular adhesion molecule-1 (ICAM-1) expression was quantified using the dual radiolabeled monoclonal antibody technique and Mac-1 (CD11b/CD18) expression on leukocytes by flow cytometry. Leukocyte infiltration was monitored by tissue myeloperoxidase (MPO) activity. The first indomethacin injection induced a time- and site-dependent increase of ICAM-1 expression in ileal mucosa and muscularis. The second injection resulted in a reduction of ICAM-1 expression below constitutive levels whereas Mac-1 was upregulated. MPO changes paralleled lesion development over 48 h. ICAM-1 and MPO values were correlated for the first 24 h. Immunoneutralization of either ICAM-1 or Mac-1 attenuated mucosal injury. We conclude that (i) indomethacin-induced ileitis is associated with a temporally disassociated upregulation of ICAM-1 and (ii) despite a reduction in ICAM-1 after 24 h, ICAM-1, in concert with Mac-1, contributes to mucosal injury and leukocyte infiltration elicited by indomethacin.

Entrapment of the popliteal artery and its surgical management in a 20-year period.

BACKGROUND: This study was a retrospective review of 19 patients with popliteal artery entrapment syndrome (PAES) treated in a 20-year interval. METHODS: The Heidelberg classification of PAES was used, which differentiates three categories of entrapment: in type I the popliteal artery has an atypical course, in type II the muscular insertion is atypical, and in type III both conditions are present. Besides decompression of the popliteal artery the commonest operative reconstruction used was resection of the atherosclerotic part of the artery and autologous vein interposition grafting (n = 12). Local thromboendarterectomy was done in seven cases, six with a vein patch angioplasty repair. RESULTS: Follow-up ranged from 6 months to 20 years (mean 9.5 years). There was no limb loss. The rate of complications was lowest after primary venous interposition (two of 12) compared with five of 11 when venous interposition was not used (P < 0.01). CONCLUSION: Autologous saphenous vein interposition grafting seems to be the best treatment for PAES.

Altered expression of cell adhesion molecules in uninvolved gut in inflammatory bowel disease.

Adhesion of circulating cells to vascular endothelium occurs in the early phase of inflammation, and is mediated by specific cell adhesion molecules. Many such adhesion molecules are increased in inflamed regions of ulcerative colitis (UC) and Crohn's disease (CD) but there is limited knowledge of their expression in the uninvolved gut, adjacent to inflammation. We investigated immunohistochemically the expression of platelet endothelial cell adhesion molecule-1 (PECAM-1), intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function-associated antigen-1 (LFA-1) on resected specimens taken at a distance of 2-4 cm from the inflamed area and without histological signs of inflammation. Compared with normal gut, we found (i) a significant increase of PECAM-1-positive vessels in the mucosa of uninvolved UC (149.0 +/- 24.1 vessels/mm2 (mean +/- s.d.); normal colon = 123.1 +/- 21.6; P = 0.004); (ii) a significant decrease of ICAM-1-positive vessels in uninvolved CD (111.9 +/- 22.6 vessels/mm2; normal ileum = 136.9 +/- 27.6; P = 0.04); and (iii) a moderate but statistically insignificant increase of LFA-1-positive cells in the mucosa of uninvolved UC and Crohn's ileitis. This altered expression of cell adhesion molecules may contribute to the early lesion in inflammatory bowel disease and provide new therapeutic opportunities.