Local delivery of anti-monocyte chemoattractant protein-1 by gene-eluting stents attenuates in-stent stenosis in rabbits and monkeys

The anti-inflammatory agent bindarit inhibits neointima formation in both rats and hyperlipidaemic mice

AIMS

Bindarit is an original compound with peculiar anti-inflammatory activity due to a selective inhibition of a subfamily of inflammatory chemokines, including the monocyte chemotactic proteins MCP-1/CCL2, MCP-3/CCL7, and MCP-2/CCL8. In this study, we investigated the effect of bindarit on neointima formation using two animal models of arterial injury: rat carotid artery balloon angioplasty and wire-induced carotid injury in apolipoprotein E-deficient (apoE(-/-)) mice.

METHODS AND RESULTS

Treatment of rats with bindarit (200 mg/kg/day) significantly reduced balloon injury-induced neointima formation by 39% at day 14 without affecting re-endothelialization and reduced the number of medial and neointimal proliferating cells at day 7 by 54 and 30%, respectively. These effects were associated with a significant reduction of MCP-1 levels both in sera and in injured carotid arteries of rats treated with bindarit. In addition, in vitro data showed that bindarit (10-300 microM) reduced rat vascular smooth muscle cell (VSMC) proliferation, migration, and invasion, processes contributing to the injury-induced neointima formation in vivo. Similar results were observed in hypercholesterolaemic apoE(-/-) mice in which bindarit administration resulted in a 42% reduction of the number of proliferating cells at day 7 after carotid injury and in a 47% inhibition of neointima formation at day 28. Analysis of the cellular composition in neointimal lesions of apoE(-/-) mice treated with bindarit showed that the relative content of macrophages and the number of VSMCs were reduced by 66 and 30%, respectively, compared with the control group.

CONCLUSION

This study demonstrates that bindarit is effective in reducing neointima formation in both non-hyperlipidaemic and hyperlipidaemic animal models of vascular injury by a direct effect on VSMC proliferation and migration and by reducing neointimal macrophage content. All of these data were associated with the inhibition of MCP-1 production.

Soluble Flt-1 gene transfer ameliorates neointima formation after wire injury in flt-1 tyrosine kinase-deficient mice

OBJECTIVE

We have demonstrated that vascular endothelial growth factor (VEGF) expression is upregulated in injured vascular wall, and blockade of VEGF inhibited monocyte infiltration and neointima formation in several animal models. In the present study, we aimed to clarify relative role of two VEGF receptors, flt-1 versus flk-1/KDR, in neointima formation after injury using flt-1 tyrosine kinase-deficient (Flt-1 TK(-/-)) mice and soluble Flt-1(sFlt-1) gene transfer.

METHODS AND RESULTS

Neointima formation was comparable between wild-type and Flt-1 TK(-/-) mice 28 days after intraluminal wire injury in femoral arteries. By contrast, neointima formation was significantly suppressed by sFlt-1 gene transfer into Flt-1 TK(-/-) mice that blocks VEGF action on flk-1 (intima/media ratio: 2.8+/-0.4 versus 1.4+/-0.4, P<0.05). The inhibition of neointima formation was preceded by significant reduction of monocyte chemoattractant protein (MCP-1) expression in vascular smooth muscle cells (VSMCs) and monocyte infiltration 7 days after injury. Gene transfer of sFlt-1 or treatment of flk-1-specific antibody significantly inhibited VEGF-induced MCP-1 expression determined by RT-PCR in cultured aortic tissue and VSMCs. MCP-1-induced chemotaxis was equivalent between wild-type and Flt-1 TK(-/-) mice.

CONCLUSIONS

These results suggest that endogenous VEGF accelerates neointima formation through flk-1 by regulating MCP-1 expression in VSMCs and macrophage-mediated inflammation in injured vascular wall in murine model of wire injury.

Development of cardiovascular bypass grafts: endothelialization and applications of nanotechnology

There is a critical clinical need for small-diameter bypass grafts, with applications involved in the coronary artery and lower limb. Commercially available materials give rise to unfavorable responses when in contact with blood and subjected to low-flow hemodynamics and, thus, are nonideal as small-diameter bypass grafts. Optimizing the mechanical properties to match both the native artery and the graft surfaces has received keen attention. Endothelialization of bypass grafts is considered a protective mechanism where the biochemicals produced from endothelial cells exert a range of favorable responses, including antithrombotic, noninflammatory responses and inhibition of intimal hyperplasia. In situ endothelialization is most desirable. Nanotechnology approaches facilitate all aspects of endothelialization, including endothelial progenitor cell mobilization, migration, adhesion, proliferation and differentiation. 'Surface nanoarchitecturing mechanisms', which mimic the natural extracellular matrix to optimize endothelial progenitor cell interaction and controlled delivery of various factors in the form of nanoparticles, which can be combined with gene therapy, are of keen interest. This article discusses the development of bypass grafts, focusing on the optimization of the biological properties of mechanically suitable grafts.

Long-term follow up of initial clinical cases with NF-kappaB decoy oligodeoxynucleotide transfection at the site of coronary stenting

BACKGROUND

An essential transcription factor for inflammation, nuclear factor-kappa B (NF-kappaB), plays a pivotal role for restenosis after percutaneous coronary intervention (PCI). To evaluate the safety and effectiveness of NF-kappaB decoy oligodeoxynucleotides (ODN) to prevent restenosis, we initiated an open-label phase I/IIa clinical trial.

METHODS

Seventeen patients who were suffering from angina with organic coronary stenosis were treated with NF-kappaB decoy ODN after PCI using bare metal stents.

RESULTS

Although the average coronary stenosis was 90.8 +/- 7.0% before the stent implantation, the stenosis improved to 1.4 +/- 5.9% after the intervention. Serum MCP-1 levels were significantly suppressed in NF-kappaB decoy ODN treated patients compared to those in non-treated patients on day 3 after the PCI. Ticlopidine treatment was employed, since clopidogrel was not launched in Japan. Six months after the PCI and decoy ODN transfection, significant restenosis was found in only 1 of the 17 patients, and the average restenosis rate was 39.6 +/- 22.3%. No in-stent thrombosis was found and no significant systemic adverse effect occurred in any of the patients in this observation period.

CONCLUSIONS

These results suggest the clinical usefulness and safety of the NF-kappaB decoy ODN transfer after PCI, although further placebo control trials are necessary.