Effect of polymer-free TiO2 stent coated with abciximab or alpha lipoic acid in porcine coronary restenosis model.

BACKGROUND: Polymer-free drug-eluting stents (DES) may overcome the shortcomings of polymer-based DES. The aim of this study was to examine the effect of the polymer-free TiO2 film-coated stent with abciximab or alpha lipoic acid in a porcine coronary overstretch restenosis model. METHODS: Pigs were randomized into four groups in which the coronary arteries (24 pigs, 48 coronaries in each group) had TiO2 film-coated stent with abciximab (TCA, n = 12), TiO2 film-coated stent with alpha lipoic acid (TCALA, n = 12), biolimus A9-eluting stents with biodegradable polymer (BES, n = 12), and TiO2 film-coated stent (TCstent, n = 12). Histopathologic analysis was performed at 28 days after stenting. RESULTS: There was no significant difference in the injury score and internal elastic lamina (IEL) among the four groups. There were significant differences in the lumen area, neointima area, percent area stenosis, fibrin score, and inflammation score among the four groups [2.7 ± 1.0mm(2), 2.6 ± 0.94 mm(2), 48.9 ± 16.25%, 1.0 (range 0.0-3.0), 1.0 (range 0.0-2.0) in TCA stent group vs. 2.7 ± 1.24 mm(2), 2.9 ± 0.83 mm(2), 53.5 ± 17.19%, 1.0 (range 0.0-2.0), 1.0 (range 0.0-2.0) in TCALA stent group vs. 2.7 ± 1.30 mm(2), 2.6 ± 1.06 mm(2), 50.1 ± 23.20%, 2.0 (range 1.0-3.0), 2.0 (range 1.0-3.0) in BES group vs. 1.7 ± 0.63 mm(2), 3.3 ± 0.58 mm(2), 60.2 ± 10.12%, 0.5 (range 0.0-2.0), 1.0 (range 0.0-2.0) in TC stent group, respectively]. CONCLUSION: TCA and TCALA are more effective to reduce neointimal hyperplasia compared to TC. Moreover, fibrin and inflammation scores are significantly lower in TCA and TCALA than BES in porcine coronary restenosis model.

Effects of ramiprilat-coated stents on neointimal hyperplasia, inflammation, and arterial healing in a porcine coronary restenosis model.

BACKGROUND AND OBJECTIVES: The renin-angiotensin-aldosterone system has been implicated in the pathogenesis of neointimal hyperplasia, and a role for angiotensin II in the migration and proliferation of vascular smooth muscle cells in restenotic lesions has been proposed. The aim of this study was to determine the anti-proliferative and anti-inflammatory effects of ramiprilat-coated stents in a porcine coronary overstretch restenosis model. SUBJECTS AND METHODS: Pigs were randomized into two groups in which the coronary arteries {16 pigs (16 coronaries in each group)} had a 3.0×17 mm ramiprilat-coated MAC stent or a 3.0×17 mm control MAC stent (AMG, Munich, Germany) implanted with oversizing (stent-to-artery ratio, 1.3 : 1) in porcine coronary arteries, and histopathologic analysis was assessed 28 days after stenting. RESULTS: There were no significant differences in the injury and inflammation scores between the two groups (1.20±0.43 vs. 1.23±0.57, p=0.8; and 1.21±0.39 vs. 1.25±0.49, p=0.6, respectively). Within the neointima, most inflammatory cells were lymphohistiocytes. Significant positive correlations existed between inflammatory cell counts and the neointima areas (r=0.567, p<0.001), and between inflammatory cell counts and the percent area stenosis (r=0.478, p<0.001). There was no significant difference in the inflammatory cell counts normalized to the injury (110±89 vs. 123±83, p=0.4) and fibrin scores (0.15±0.06 vs. 0.17±0.07, p=0.8) between the 2 groups. There were trends toward a smaller neointima area (1.06±0.51 mm(2) vs. 1.28±0.35 mm(2), p=0.083) and a smaller percent area stenosis (18.9±8.7% vs. 21.8±7.2%, p=0.088) in the ramiprilat-coated stent group. CONCLUSION: Although the ramiprilat-coated stent did not show significant inhibitory effects on neointimal hyperplasia, the ramiprilat-coated stent showed good effects on the inflammatory reaction and arterial healing similar to the control stent in a porcine coronary restenosis model.

Effect of a dual drug-coated stent with abciximab and alpha-lipoic Acid in a porcine coronary restenosis model.

BACKGROUND AND OBJECTIVES: The aim of this study was to examine the anti-proliferative and anti-inflammatory effects of a stent coated with abciximab and alpha-lipoic acid (ALA) in a porcine coronary overstretch restenosis model. MATERIALS AND METHODS: A total of 10 pigs were randomized into two groups (10 pigs, 10 coronaries in each group) in which the coronary arteries were stented with a dual-coated stent and a bare metal stent (control) by randomization. Stents were deployed with oversizing (stent/artery ratio 1.3 : 1) in the porcine coronary arteries, and histopathology was assessed 28 days after stenting. RESULTS: There was no significant difference in the injury score between the two groups. In the neointima, the lymphohistiocyte count was significantly lower in dual-coat stent group compared with the control stent group (120±85 cells vs. 159±80 cells, p=0.048). There was no significant difference in the fibrin score between the two groups (0.16±0.34 in the dual-coated stent group vs. 0.25±0.48 in the control stent group, p=0.446). The neointima area was not significantly different between both groups (1.55±0.8 mm(2) in dual-coated stent group vs. 1.40±0.86 mm(2) in the control stent group, p=0.447). CONCLUSION: Although the dual-coated stent with abciximab and ALA showed no significant difference in inhibition of neointimal hyperplasia when compared with the bare metal stent, it was associated with a reduced inflammatory reaction when compared with the control stent in a porcine coronary restenosis model.

Adsorption of pyridine onto the metal organic framework MIL-101.

The adsorption of pyridine onto the metal organic framework MIL-101 was investigated by experimental and theoretical methods. The amount of pyridine adsorbed on MIL-101 was extraordinarily large at 20 °C, corresponding to about 950 mg/g of dried MIL-101 and approximately half of the voids being filled. Most of the pyridine that had filled the voids was rapidly removed by evacuation at room temperature, but some of the pyridine was so strongly adsorbed that it was retained even under evacuation at 150 °C. Although IR spectra of the adsorbed pyridine indicated the adsorption of pyridine as pyridinium ions and coordinated pyridine at low temperatures, increasing the adsorption temperature induced partial cleavage of the pyridine rings. The high stabilization energy of pyridine on the coordinative unsaturated sites (CUS) of MIL-101, obtained by theoretical calculation, -103 kJ/mol, supported the strong adsorption of pyridine on the CUS.

Two-year clinical outcome after abciximab-coated stent implantation in patients with coronary artery disease.

BACKGROUND: Despite abciximab-coated stents having an inhibitory effect on coronary artery restenosis, the medium-term clinical outcome is unknown. METHODS AND RESULTS: This prospective, randomized study compared the effects of the abciximab-coated stent, which was implanted in 95 patients, with those of control bare metal stents (BMS) implanted in 93 patients for de novo coronary lesions. Stent implantation was performed without any complications associated with the procedure. The 6-month intravascular ultrasound analysis showed that the area of neointimal hyperplasia was significantly smaller in the abciximab-coated stent group compared with the control stent group (+2.0+/-1.6 mm(2) vs +3.4+/-1.7 mm(2), P=0.001). However, at 2-year clinical follow up, there were no statistically significant differences in the incidences of total major adverse cardiac events (16% vs 24%, P=0.19) and cardiac death (0% vs 1.1%, P=0.3), target vessel revascularization (16% vs 21%, P=0.4) or non-fatal myocardial infarction (0% vs 2.3%, P=0.16) in the abciximab-coated stent group compared with the control stent group. CONCLUSIONS: Although abciximab-coated stents are safe and inhibit neointimal hyperplasia, they have no superiority over BMS in 2-year clinical outcome.

Effect of alpha lipoic acid in a porcine in-stent restenosis model.

BACKGROUND: The aim of this study was to investigate the effect of alpha lipoic acid (α-LA) on a porcine in-stent restenosis (ISR) model. METHODS: In protocol 1, porcine vascular smooth muscle cells (PVSMC) were stimulated by granulocyte-colony stimulating factor (G-CSF) in the presence or absence of α-LA. MTT (3-[4,5-dimethylthiazole-2-yl] 2,5-diphenyl tetrazolium bromide) assay and western blotting were used to determine the cell growth inhibitory rate and anti-inflammatory effect associated with nuclear factor-κb (NF-κb) and extracellular signal-regulated kinase (ERK). In protocol 2, 28 days after balloon overdilation injuries, 24 bare metal stents were placed in coronary artery of 12 pigs. The pigs were randomly divided to receive control diet with or without α-LA (100 mg/kg). In protocol 3, 8 control stents and 8 α-LA coated stents were randomly implanted in 2 coronary arteries of 8 pigs and follow-up coronary angiogram and histopathologic assessment were performed 4 weeks after stenting. RESULTS: Protocol 1. The proliferation of PVSMC was inhibited and protein expression of NF-κb and ERK were attenuated by α-LA pretreatment. Protocol 2. On histopathologic analysis, the neointimal area (4.0+/-1.0 mm(2) vs. 1.5+/-0.7 mm(2), p<0.001) and histopathologic area of stenosis (66.7+/-10.7% vs. 24.2+/-9.7%, p<0.001) were reduced in the α-LA feeding group compared to controls. Protocol 3. On histopathologic analysis, the neointimal area (3.9+/-0.8 mm(2) vs. 1.0+/-0.4 mm(2), p<0.001), and the histopathologic area of stenosis (67.1+/-8.8% vs. 17.4+/-10.0%, p<0.001) were reduced in the α-LA coated stent group compared to the control stent group. CONCLUSIONS: α-LA feeding and α-LA coated stents inhibit neointimal hyperplasia in porcine ISR, possibly through inhibiting the activation of NF-κb pathway and proliferation of PVSMC.