- Email: [email protected]
Effect of Beraprost Sodium on Neointimal Hyperplasia After Stent Implantation: Experimental Study in Canine
The DNFGFR transgene blunted FGF-mediated (but not serum-mediated) MAPK activity and c-fos expression in vitro. The DNSRF trans gene attenuated SRFdependent gene transcription in cultured SMC. The Infiltrator catheter delivered adenovirus intramurally as deep as the adventitial compartment of the rabbit iliac artery as evidenced by the specific transgene expression (lacZ) in adventitial myofibroblasts. No endothelial staining was observed. Conclusions: The SM22 promoter directs high level, specific expression of transgenes that attenuate the biological response of SMC to growth stimuli. Coupling the specificity of the SM22 promoter with the time-efficient intramural delivery of adenovirus represents a rational approach for treating vascular occlusive lesions.
Poster No. 403 Comparative Trial of Local Pharmacotherapy With L-Arginine, r-Hirudin and Molsidomine To Reduce Restenosis After Balloon Angioplasty of Stenotic Rabbit Iliac Arteries M. Kalinowski, Marburg, Germany • S. Bergen • H. Aifke • K.]. Klose • H.I Wagner PURPOSE: To compare efficacy of local application of i-arginine, r-hirudin and molsidomine in reducing intimal hyperplasia after balloon dilation of stenotic rabbit iliac arteries. MATERIALS AND METHODS: Thirtyone male cholesterol-fed New Zealand white rabbits underwent balloon denudation of both common iliac arteries to induce an arterial stenosis. Four weeks after stenosis induction one of the stenotic iliac arteries (randomly selected) were simultaneously dilated and received local application of i-arginine (21Omg/ml;n=7), r-hirudin (0.5mg/ml; n=S) or molsidomine (0.2mg/ml; n=S) over a channeled balloon catheter. On the contralateral side 0.9% saline was injected as a control. In S zero controls saline was applied to one iliac artery and balloon dilation only to the contralateral artery. The channeled balloon catheter allows simultaneous balloon dilation (Satm) of the stenosis and local application of the drug solution (4atm).Balioon dilation and drug infusion time was 3 minutes. Six weeks after local treatment, vessels were harvested and computerized morphometric and immunohistological analyses were performed.
448
RESULTS: Application of i-arginine resulted in a significant reduction of neointimal area (NA): 1.01mm z versus 2.17mm z (-S3%); intima/media ratio (IM) 1.07 versus 2.3; p<0.05; molsidomine decreased NA by 43% (l.04mm z versus l.S9mmz; 1M ratio: 1.S6 versus 1.92; p
reduction of macrophages (S% versus 10.2%;p<0.OS) and proliferating cells (6.2% versus 10.6%;p<0.OS) in the neointima after local application of i-arginine. CONCLUSIONS: Reduction of neointima area was significant for the NO-donors i-arginine and molsidomine. However, saline infusion causes significant arterial trauma resulting in additional neointima proliferation. Application pressures and volumes have to be improved to enhance the effect of the local application to prevent restenosis after PTA.
Poster No. 404 Effect of Beraprost Sodium on Neointimal Hyperplasia After Stent Implantation: Experimental Study in Canine K. Seiji, Sendai, Japan • T Matsuhashi • H. Miyachi • T Ishibashi • S. Takahashi • S. Yamada PURPOSE: Endovascular stents are a widely accepted treatment for stenotic vascular lesions. However, acute thrombosis and late neointimal formation remain a concern. Therefore, we tested the hypothesis that shortterm administration of beraprost sodium (beraprost), a stable prostaglandin 12 analogue with antiplatelet-aggregatory and anti proliferative activities, would reduce neointimal thickening after stent implantation. MATERIALS AND METHODS: In the 1st part of this study, Z-stents were placed in the iliac veins of 12 dogs. Six dogs were infused with beraprost and the other 6 dogs were infused with saline as a control group. Both saline and beraprost (0.3S Ilg/kg/min) were administered intravenously for five and a half hours, beginning 30 minutes before stent implantation. Platelet aggregation induced by adenosine S'diphosphate (SIlM) was measured before and after drug administration. In both groups, two dogs were killed on each of days 3, 7, and 14 after stent implantation. Proliferation of vascular smooth muscle cells (SMCs) was quantified by immunohistochemical staining with proliferating cell nuclear antigen (PCNA). In the 2nd part of this study we used another 10 dogs. A Z-stent was placed in the right iliac vein with beraprost infusion. Three days later, another Z-stent was placed contra laterally with saline infusion as a control. At 4 weeks, the dogs were sacrificed, and neointimal thickness was measured under light microscopy using the intima to media area ratio. The measurements were analyzed statistically. RESULTS: All the vessels were patent at the time of harvest. Ex vivo platelet aggregation was significantly suppressed in the treated group, by approximately 30% compared to the control group (p = 0.01). SMC proliferative activiry was significantly lower in the treated group than in the untreated group 7 and 14 days after stenting. We observed a significant difference in the intima to media area ratio between the treated and untreated sides O.30±0.SO versus 2.00±1.23, respectively; p < O.OS).
CONCLUSIONS: Short-term administration of beraprost
significantly suppresses aggregation and SMC proliferation, and subsequently reduces neointimal thickening after stent implantation.
Poster No. 405 Chimeric P27-p16 Gene Therapy Inhibits Balloon Injury Induced Neointimal Hyperplasia in Cholesterol-Fed Rabbits L. l:'wi. Foster City, CA • I llkArthur • 1. Lamphere • j. Gyuris • S. George. H. Qian Cyclin dependent kinase inhibitors (CDKi's) such as p16 and may be useful to treat hyperproliferative vascular disorders, such as restenosis following angioplasty and vein graft disease. We have shown that novel fusion protein of p27 and p16, named W9, significantly reduces proliferation of human coronary smooth muscle cells in vitro, by blocking cells in Gl without inducing apoptosis. We have now evaluated the efficacy of adenovirus-mediated gene transfer of W9 (Ad·W9) in a balloon injwy model, in carotid aneries from cholesterol fed rabbits. Using 3 different balloon injury-virus delivery protocols, we observed that intravascular delivery of 2.5 x 1011 v.p. of AV-W9 inhibited balloon induced intimal hyperplasia 44-49% compared to a control virus PCNA expression in the Ad-W9 treated vessels, a marker of injury induced-cell proliferation, was also reduced compared to the control virus treated vessels. Direct comparison of the efficacy of Ad-W9 with Ad-pI6, -p21, and in this model are We conclude that Ad-W9 effectively limits intimal hyperplasia following in vivo balloon injury, and represents a promising potential approach to preventing post-angioplasty restenosis.
Poster No. 406 Local Delivery of C-Myc Antisense Oligonucleotides (ASO) to Prevent Intimal Hyperplasia (IH) in a Porcine Arterial Stent Model T Hasebe, Tokyo, Japan • K. Kandarpa • S. Okuda • H. Koike • PS. Dunning • JI Barry PURPOSH: C-myc is a cell-cycle regulatory gene for
smooth muscle cells (SMC). We delivered imramural cmyc A.'iO to determine if III can be following arterial stenting by inhibiting SMC proliferation. MATERIALS AJ\7J METHODS: Both external iliac arteries
were stented (Palmaz stent-to-artery diameter ratio: 1,2 1.4) via the carotid artery, following full heparinization, in 24 Yorkshire pigs. Pigs were treated in four groups of six each as follows - ASO: 10mg c-myc ASO delivered locally (2ml over 3 minutes) with a channel-balloon following stenting; seo: lOmg scrambled-sequence oligonucleotide delivered as above; SAL: equal volume of saline only delivered as above; and SYO: 20 mg systemic c-myc ASO delivered intravenously. The pigs were euthanized two weeks later, stent specimens recovered and prepared (Movat stain) for morphometric analysis (three sections per stent), Percent area stenosis
(PAS= mELA, internal elastic lamina area - lumen arealllIELA]} x100) was computed. ANOVA statistics were applied; Significance at p< 0.05. PAS, mean (SOl: ASO=11.97 (4.51), SCO=12.41 (5.12), SAL=14.61 (6.04), SYO=958 (2.37) ANOVA F-stalistic, p= .0006. Fisher?s PLSD p-values for inter-group differences were: SAL Vs SYO, < .0001; SAL Vs ASO, .022; SAL Vs SCO, .066(ns); SYO Vs ASO, .042; SYO Vs SCO, .021; ASO Vs SCO, .712 (ns). RESULTS:
CONCLUSIONS: Systemic and local delivery of c-myc ASO. but not local SCO, minimized PAS to a greater degree than local saline. Interestingly, systemic delivery was superior to local delivery of c-myc ASO. This, and the lack of a significant difference bern'een the local cmyc ASO and SCO groups suggests. that under the present conditions, local drug delivery may have caused additional mural trauma and IH.
Poster No. 407 PhotodynamiC Therapy in a Swine Restenosis Model Using a New Guidewire Compatible Laser Catheter c.A. A1cElroy, Los Angeles. CA • I.M. Leitch • P Stephens. IP Walker· R. Grove • S.c. Goodu'in PURPOSE: Intravascular photodynamic therapy (PDT)
has been shown to effectively inhibit restenosis in pre clinical animal models. The objectives of this study were to CD determine the safety, effective dose range and acute PDT effects of a novel photosensitive drug (MV640l) in swine iliac arteries: and (m optimize a novel laser light delivery catheter developed specifically for endovascular PDT. Such information would aid in future PDT studies focused on increasing long term pa· tency following angioplasty. MATERIALS AND ;1;1EIHODS' We studied 20 iliac arterial
segments in five animals (2 treatment segments/artery). Treatment groups were: (a) control: no injury, no drug, no light; (b) injury only (30o/c, overstretch for 3min).no drug, no light: (e) injury, plus Mv6401 and light. Several Mv6401 doses (0.03 - '5mg) were locally administered using an intra-arterial drug-diffusing balloon catheter. Endovascular light treatment (30 J!cm 2 for 3405ec) was delivered locally in the iliac arteries. Vital signs and ECG were monitored during all procedures. Four later, animals were sacrificed and arterial segments were analyzed histologically. RESULT5: [\'0 vascular complications were observed from PDT and all arteries were patent on day 4 angiograms. Local drug and light delivery caused dose-dependent decreases in cell numbers in the medial layer of the iliac ar teries. Acellular media was not found in untreated injured aneries or injured aneries treated with low dose Mv6401 (<1mg) plus light. No significant changes in heart rate or ECG were noted during PDT treatment. CONCLUSIONS· These data demonstrate that PDT can effectively be administered using local delivery catheters.
449
Poster No. 403 Comparative Trial of Local Pharmacotherapy With L-Arginine, r-Hirudin and Molsidomine To Reduce Restenosis After Balloon Angioplasty of Stenotic Rabbit Iliac Arteries M. Kalinowski, Marburg, Germany • S. Bergen • H. Aifke • K.]. Klose • H.I Wagner PURPOSE: To compare efficacy of local application of i-arginine, r-hirudin and molsidomine in reducing intimal hyperplasia after balloon dilation of stenotic rabbit iliac arteries. MATERIALS AND METHODS: Thirtyone male cholesterol-fed New Zealand white rabbits underwent balloon denudation of both common iliac arteries to induce an arterial stenosis. Four weeks after stenosis induction one of the stenotic iliac arteries (randomly selected) were simultaneously dilated and received local application of i-arginine (21Omg/ml;n=7), r-hirudin (0.5mg/ml; n=S) or molsidomine (0.2mg/ml; n=S) over a channeled balloon catheter. On the contralateral side 0.9% saline was injected as a control. In S zero controls saline was applied to one iliac artery and balloon dilation only to the contralateral artery. The channeled balloon catheter allows simultaneous balloon dilation (Satm) of the stenosis and local application of the drug solution (4atm).Balioon dilation and drug infusion time was 3 minutes. Six weeks after local treatment, vessels were harvested and computerized morphometric and immunohistological analyses were performed.
448
RESULTS: Application of i-arginine resulted in a significant reduction of neointimal area (NA): 1.01mm z versus 2.17mm z (-S3%); intima/media ratio (IM) 1.07 versus 2.3; p<0.05; molsidomine decreased NA by 43% (l.04mm z versus l.S9mmz; 1M ratio: 1.S6 versus 1.92; p
reduction of macrophages (S% versus 10.2%;p<0.OS) and proliferating cells (6.2% versus 10.6%;p<0.OS) in the neointima after local application of i-arginine. CONCLUSIONS: Reduction of neointima area was significant for the NO-donors i-arginine and molsidomine. However, saline infusion causes significant arterial trauma resulting in additional neointima proliferation. Application pressures and volumes have to be improved to enhance the effect of the local application to prevent restenosis after PTA.
Poster No. 404 Effect of Beraprost Sodium on Neointimal Hyperplasia After Stent Implantation: Experimental Study in Canine K. Seiji, Sendai, Japan • T Matsuhashi • H. Miyachi • T Ishibashi • S. Takahashi • S. Yamada PURPOSE: Endovascular stents are a widely accepted treatment for stenotic vascular lesions. However, acute thrombosis and late neointimal formation remain a concern. Therefore, we tested the hypothesis that shortterm administration of beraprost sodium (beraprost), a stable prostaglandin 12 analogue with antiplatelet-aggregatory and anti proliferative activities, would reduce neointimal thickening after stent implantation. MATERIALS AND METHODS: In the 1st part of this study, Z-stents were placed in the iliac veins of 12 dogs. Six dogs were infused with beraprost and the other 6 dogs were infused with saline as a control group. Both saline and beraprost (0.3S Ilg/kg/min) were administered intravenously for five and a half hours, beginning 30 minutes before stent implantation. Platelet aggregation induced by adenosine S'diphosphate (SIlM) was measured before and after drug administration. In both groups, two dogs were killed on each of days 3, 7, and 14 after stent implantation. Proliferation of vascular smooth muscle cells (SMCs) was quantified by immunohistochemical staining with proliferating cell nuclear antigen (PCNA). In the 2nd part of this study we used another 10 dogs. A Z-stent was placed in the right iliac vein with beraprost infusion. Three days later, another Z-stent was placed contra laterally with saline infusion as a control. At 4 weeks, the dogs were sacrificed, and neointimal thickness was measured under light microscopy using the intima to media area ratio. The measurements were analyzed statistically. RESULTS: All the vessels were patent at the time of harvest. Ex vivo platelet aggregation was significantly suppressed in the treated group, by approximately 30% compared to the control group (p = 0.01). SMC proliferative activiry was significantly lower in the treated group than in the untreated group 7 and 14 days after stenting. We observed a significant difference in the intima to media area ratio between the treated and untreated sides O.30±0.SO versus 2.00±1.23, respectively; p < O.OS).
CONCLUSIONS: Short-term administration of beraprost
significantly suppresses aggregation and SMC proliferation, and subsequently reduces neointimal thickening after stent implantation.
Poster No. 405 Chimeric P27-p16 Gene Therapy Inhibits Balloon Injury Induced Neointimal Hyperplasia in Cholesterol-Fed Rabbits L. l:'wi. Foster City, CA • I llkArthur • 1. Lamphere • j. Gyuris • S. George. H. Qian Cyclin dependent kinase inhibitors (CDKi's) such as p16 and may be useful to treat hyperproliferative vascular disorders, such as restenosis following angioplasty and vein graft disease. We have shown that novel fusion protein of p27 and p16, named W9, significantly reduces proliferation of human coronary smooth muscle cells in vitro, by blocking cells in Gl without inducing apoptosis. We have now evaluated the efficacy of adenovirus-mediated gene transfer of W9 (Ad·W9) in a balloon injwy model, in carotid aneries from cholesterol fed rabbits. Using 3 different balloon injury-virus delivery protocols, we observed that intravascular delivery of 2.5 x 1011 v.p. of AV-W9 inhibited balloon induced intimal hyperplasia 44-49% compared to a control virus PCNA expression in the Ad-W9 treated vessels, a marker of injury induced-cell proliferation, was also reduced compared to the control virus treated vessels. Direct comparison of the efficacy of Ad-W9 with Ad-pI6, -p21, and in this model are We conclude that Ad-W9 effectively limits intimal hyperplasia following in vivo balloon injury, and represents a promising potential approach to preventing post-angioplasty restenosis.
Poster No. 406 Local Delivery of C-Myc Antisense Oligonucleotides (ASO) to Prevent Intimal Hyperplasia (IH) in a Porcine Arterial Stent Model T Hasebe, Tokyo, Japan • K. Kandarpa • S. Okuda • H. Koike • PS. Dunning • JI Barry PURPOSH: C-myc is a cell-cycle regulatory gene for
smooth muscle cells (SMC). We delivered imramural cmyc A.'iO to determine if III can be following arterial stenting by inhibiting SMC proliferation. MATERIALS AJ\7J METHODS: Both external iliac arteries
were stented (Palmaz stent-to-artery diameter ratio: 1,2 1.4) via the carotid artery, following full heparinization, in 24 Yorkshire pigs. Pigs were treated in four groups of six each as follows - ASO: 10mg c-myc ASO delivered locally (2ml over 3 minutes) with a channel-balloon following stenting; seo: lOmg scrambled-sequence oligonucleotide delivered as above; SAL: equal volume of saline only delivered as above; and SYO: 20 mg systemic c-myc ASO delivered intravenously. The pigs were euthanized two weeks later, stent specimens recovered and prepared (Movat stain) for morphometric analysis (three sections per stent), Percent area stenosis
(PAS= mELA, internal elastic lamina area - lumen arealllIELA]} x100) was computed. ANOVA statistics were applied; Significance at p< 0.05. PAS, mean (SOl: ASO=11.97 (4.51), SCO=12.41 (5.12), SAL=14.61 (6.04), SYO=958 (2.37) ANOVA F-stalistic, p= .0006. Fisher?s PLSD p-values for inter-group differences were: SAL Vs SYO, < .0001; SAL Vs ASO, .022; SAL Vs SCO, .066(ns); SYO Vs ASO, .042; SYO Vs SCO, .021; ASO Vs SCO, .712 (ns). RESULTS:
CONCLUSIONS: Systemic and local delivery of c-myc ASO. but not local SCO, minimized PAS to a greater degree than local saline. Interestingly, systemic delivery was superior to local delivery of c-myc ASO. This, and the lack of a significant difference bern'een the local cmyc ASO and SCO groups suggests. that under the present conditions, local drug delivery may have caused additional mural trauma and IH.
Poster No. 407 PhotodynamiC Therapy in a Swine Restenosis Model Using a New Guidewire Compatible Laser Catheter c.A. A1cElroy, Los Angeles. CA • I.M. Leitch • P Stephens. IP Walker· R. Grove • S.c. Goodu'in PURPOSE: Intravascular photodynamic therapy (PDT)
has been shown to effectively inhibit restenosis in pre clinical animal models. The objectives of this study were to CD determine the safety, effective dose range and acute PDT effects of a novel photosensitive drug (MV640l) in swine iliac arteries: and (m optimize a novel laser light delivery catheter developed specifically for endovascular PDT. Such information would aid in future PDT studies focused on increasing long term pa· tency following angioplasty. MATERIALS AND ;1;1EIHODS' We studied 20 iliac arterial
segments in five animals (2 treatment segments/artery). Treatment groups were: (a) control: no injury, no drug, no light; (b) injury only (30o/c, overstretch for 3min).no drug, no light: (e) injury, plus Mv6401 and light. Several Mv6401 doses (0.03 - '5mg) were locally administered using an intra-arterial drug-diffusing balloon catheter. Endovascular light treatment (30 J!cm 2 for 3405ec) was delivered locally in the iliac arteries. Vital signs and ECG were monitored during all procedures. Four later, animals were sacrificed and arterial segments were analyzed histologically. RESULT5: [\'0 vascular complications were observed from PDT and all arteries were patent on day 4 angiograms. Local drug and light delivery caused dose-dependent decreases in cell numbers in the medial layer of the iliac ar teries. Acellular media was not found in untreated injured aneries or injured aneries treated with low dose Mv6401 (<1mg) plus light. No significant changes in heart rate or ECG were noted during PDT treatment. CONCLUSIONS· These data demonstrate that PDT can effectively be administered using local delivery catheters.
449