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ISSN : 1225-0112(Print)
ISSN : 2288-4505(Online)
Applied Chemistry for Engineering Vol.31 No.5 pp.502-508
DOI : https://doi.org/10.14478/ace.2020.1050

Comparison between Basic and Inverse Dual Drug and Peptide-coated Stents in a Porcine Restenosis Model

Eun-Jae Jang*,**, So-Youn Lee**,***, In-Ho Bae**,***, Dae Sung Park**,***, Myung Ho Jeong**,***,****,†, Jun-Kyu Park****,†
*Biopharmaceutical Research Center, Hwasun 58141, Korea
**The Cardiovascular Convergence Research Center of Chonnam National University, Hospital Designated by Ministry of Health and Welfare, Gwangju 61469, Korea
***Korea Cardiovascular Stent Research Institute, Jangsung 57248, Korea
****Department of Cardiology, Chonnam National University Hospital, Gwangju 61469, Korea
*****CGBio Co. Ltd, Seongnam 13211, Korea
†Corresponding Author: M. H. Jeong: Hospital Designated by Ministry of Health and Welfare, The Cardiovascular Convergence Research Center of Chonnam National University, Gwangju 61469, Korea; J.-K. Park: CGBio Co. Ltd, Seongnam 13211, Korea Tel: M. H. Jeong: +82-62-220-6243; J.-K. Park: +82-31-748-8215 e-mail: M. H. Jeong: myungho@chollian.net; J.-K. Park: pjk23@cgbio.co.kr
July 12, 2020 ; August 20, 2020 ; August 20, 2020

Abstract


Dual drug-eluting stents (DES) is a primary treatment method for coronary arterial diseases in current interventional cardiology practice. However, their pathological results according to the sequence of coating of drugs have not been reported yet. The peptide- dopamine dissolved in acetonitrile was coated onto the Chonnam National University Hospital (CNUH) stent using an electrospinning coating machine. For secondary coating (e.g., sirolimus coating, designated as SPS), sirolimus (SRL) and poly lactic-glycolic acid (PLGA) were mixed in tetrahydrofuran (THF), and the solution was then coated on the CNUH stent that had underwent the primary peptide coating using an electrospinning and spray technique. Next, the peptide-dopamine was coated on the SRL-PLGA coated stent (PSS). In this study, it was confirmed that endothelialization was promoted without being significantly affected by the coating order (SPS or PSS). The sequence of drug and peptide coating may affect the development of restenosis and PSS was effective in the prevention of restenosis compared to that of using SPS.


Dual drug eluting stent , Electro-spinning coating , Peptide , Endothelialization , Restenosis

초록

    1. Introduction

    Coronary heart disease has raised enormous concerns worldwide owing to its high morbidity and mortality. Coronary stenting has been recognized as an important method in the treatment of cardiovascular diseases[1-3]. Currently, drug-eluting stents (DES) have been used predominantly in the treatment of coronary artery blockage. A DES elutes an anti-proliferative drug that suppresses the proliferation of smooth muscle cells in the stented segment of the artery[4,5].

    However, DES implantation may cause problems. DESs may provoke cellular and biochemical events that induce pathological processes such as thrombosis and cytokine release[6]. Several studies have indicated that the possible increase in thrombotic risk after DES placement may be due to the nonspecific action of anti-mitogenic drugs on endothelial cells, leading to delayed re-endothelialization[7,8]. Many studies have suggested that rapid re-endothelial cell formation at the site of stent insertion can reduce the risk of inflammation and subsequent thrombus formation[9].

    In the setting of drug elution, the pattern of vascular healing is altered, as there is a dynamic interaction between the delayed inhibitory effect caused by the drug on smooth muscle cell and endothelial cell proliferation. Therefore, many studies in the development of any DES platform were aimed at maintaining sustained inhibition of smooth muscle cell proliferation while promoting endothelial cell coverage z [10,11]. The ideal combination of multifunctional drugs is not only an inhibitory effect on vascular smooth muscle cells, but also an endothelial cell protection, anti-inflammatory and antithrombotic effect[12].

    In this study, we developed a dual DES (DDES) that concurrently releases both an anti-proliferative drug (sirolimus) and a peptide (WKYMVm-dopamine) coated onto cobalt chromium stent. Sirolimus inhibits vascular smooth muscle cell proliferation and migration in vitro, and decreases restenosis in experimental animals[13-15]. These synthetic chemotactic peptides have become very useful probes in the study of leukocyte receptor expression and activation[16].

    Recently, WKYMVm, a hexapeptide isolated and modified from a peptide library, has been reported to be a very potent stimulant of several human leukocyte cell lines and peripheral blood neutrophils[17]. In addition, angiogenesis of endothelial cells was greatly induced via enhancement of proliferation and migration in response to the pep-tide[18].

    In an earlier paper[19], we reported the details of a successful 6-week rabbit study, in which we found that the DDES resulted in higher re-endothelialization levels. The aim of this study was to compare the pathological results between a basic and an inverse dual drug-coated system. In this work, we report on the in vitro characterization of a coated stent, DDES, implanted in a porcine coronary artery, in an effort to shed more light on DDESs.

    2. Material and Methods

    2.1. Investigated stents

    Previously, we reported on a custom-designed bare metal stent (BMS) designated the Chonnam National University Hospital (CNUH) stent[20,21]. It showed excellent performance in terms of flexibility and biocompatibility, and moderate performance in foreshortening and recoil according to the Food and Drug Administration guidelines. The CNUH stent was undoubtedly competitive compared with other stents. Therefore, it was utilized as a platform for peptide coating. Briefly, cobalt- chromium alloy (Co-Cr, L605) was used as a stent material because many researchers have reported that Co-Cr is the most appropriate material in terms of biocompatibility[22]. To prepare the CNUH stent, a Co-Cr alloy tube (3.0 mm in diameter) was cut and processed using a laser cutting machine (StarCut Tube Femto, Hamburg, Germany). To remove and crush the burr, it was placed in an acidic atmosphere (50% H2SO4) for 1h. Then, heat treatment and polishing were performed to restore the mechanical properties and smoothen the surface of the CNUH stent. The cleaned CNUH stents were kept in a vacuum oven at 60 ℃ for 2 h to evaporate the residual solvent.

    2.2. Synthesis of the peptide

    The WKYMVm-dopamine peptide was synthesized and purified by Anygen (Gwangju, Republic of Korea) according to the published sequence[ 17]. Dopamine was conjugated to the lysine moiety. The purity of the synthesized peptide was > 90%, and the amino acid composition was verified using a mass spectrophotometer (data not shown).

    2.3. Methods of coating the peptide and sirolimus on the BMS

    Drug coating was carried out through 2 consecutive steps. For the primary coating, WKYMVm-dopamine (10 mg/ml) was coated with acetonitrile and then coated onto the CNUH stent. Coating was applied using an electrospinning coating system (ESR200RD, NanoNC, Seoul, Korea) and a spray coating machine (MediCoat peripheral stent coating system; Sono-Tek, Milton, NY, USA). The solvent was removed and dried at room temperature with rotation. For the secondary coating, sirolimus (20 mg/ml) and poly-lactic-glycolic acid (50 : 50, molecular weight 12,000 Da, inherent viscosity 0.16~0.24 dl/g, 10 mg/ml) were mixed in tetrahydrofuran and coated to the CNUH stent that had undergone the primary coating procedure (with peptide) with electrospinning and spray coating machines. Stents that had undergone this sequence of drug coating were designated as the SPS group. The coating of the PSS group was as previously described, although sirolimus was the primary coating and the peptide was the secondary coating (Figure 1).

    2.4. Scanning electron microscopy

    The surface morphologies of the stents at every coating step were analyzed using a scanning electron microscope (SEM; Hitachi, Tokyo, Japan). The samples were dried overnight and sputter coated using gold before the SEM observation.

    2.5. In vitro release kinetics of drugs

    In vitro release kinetics were investigated using an ultraviolet (UV)- visible spectrophotometer (Multi Skan EX; ThermoFisher Scientific, Waltham, MA, USA). Unlike other studies that used a simple shaking procedure, equipment mimicking the body’s circulation system was designed for this study. A peristaltic pump (JenieWell, Seoul, Korea) and hydrophobic silicone tubing with various thicknesses were used to function as the heart and vasculature of the body, respectively. Three stents were inserted and then expanded in the inner lumen of the silicon tube (96410-16, tubing internal diameter: 3.1 mm; Cole-Parmer, Vernon Hills, IL, USA) using a balloon (3.0 × 20.0 mm) under 10 atm pressure. Phosphate-buffered saline (PBS) was circulated through the lumen of the tube by dipping both open ends of the silicon tube into the temperature-controlled reservoir. The rotational speed was set at 150 rpm, and unidirectional flow was used to simulate the body’s circulation system. PBS was taken out at every designated time point, and its absorbance at 275 nm was measured. The concentration of released drug was calculated by comparing it to the drug standard curve and was expressed in a cumulative manner.

    2.6. Animal preparation and stent implantation

    This animal study was approved by the Ethics Committee of Chonnam National University Medical School and CNUH (CNU IACUC-H-2014-36), and conformed to the Guide for the Care and Use of Laboratory Animals published by the US National Institutes of Health[23]. The study animals were castrated male pigs weighing 10~25 kg. To prevent acute thrombosis after stenting, premedication with aspirin 100 mg and clopidogrel 75 mg daily were given for 5 days before the procedure. On the day of the procedure, the pigs were anesthetized with zolazepam and tiletamine (2.5 mg/kg, Zoletil50®; Virbac, Caros, France), xylazine (3 mg/kg, Rompun®; BayerAG, Leverkusen, Germany), and azaperone (6 mg/kg, Stresnil®; Janssen-Cilag, Neuss, Germany). The animals continuously received supplemental oxygen through an oxygen mask. Subcutaneous 2% lidocaine was administered at the cut-down site; the left carotid artery was surgically exposed; and a 7 French sheath was inserted.

    Continuous hemodynamic and surface electrocardiographic monitoring was maintained throughout the procedure. Next, 5000 units heparin was intravenously administered as a bolus before the procedure; the target coronary artery was engaged using standard 7-Fr guide catheters; and control angiograms of both coronary arteries were obtained with a nonionic contrast agent in 2 orthogonal views. The stent was deployed by inflating the balloon, obtaining a stent-to-artery ratio of 1.3 : 1. Coronary angiograms were obtained immediately after stent implantation. Then, all equipment was removed and the carotid artery was ligated. Four weeks after stenting, the animals underwent follow- up angiography in the same orthogonal views before they were sacrificed with an intracoronary injection of 20 mL potassium chloride.

    The hearts were removed and the coronary arteries were pressure perfusion fixed at 110 mmHg in 10% neutral buffered formalin overnight. Each of the 10 stented arteries in the 3 groups was step-sectioned, processed routinely for light microscopy, and stained for histological analysis.

    2.7. Histopathological analysis

    An experienced cardiovascular pathologist performed the histopathological evaluation of each sample. The samples were sections of 50~ 100 μm and stained with hematoxylin-eosin and Carstairs’ fibrin stain for histological analysis. Measurements of the histopathological sections were performed using a calibrated microscope, digital video imaging system, and microcomputer program (Visus 2000 Visual Image Analysis System; IMT Tech,CA). Borders were manually traced for lumen area (LA), internal elastic lamina (IEL) area, and the innermost border of the external elastic lamina. Morphometric analysis of the neointimal area for a given vessel was calculated as the measured IEL area minus the LA. The measurements were made on 5 cross-sections from the proximal and distal ends and the 3 midpoints of each stented segment. Histopathological stenosis was calculated as 100 × [1 - (lesion LA / lesion IEL area)][24]. Measurements were obtained by integrating the values for all sections, and slices in the mid region of the stents were selected as representative images.

    2.8. Evaluation of arterial injury

    Arterial injury at each strut site was determined according to the anatomic structures penetrated by each strut. A numeric value was assigned, as previously described by Schwartz et[24]. as follows: 0 = no injury, 1 = break in the internal elastic membrane, 2 = perforation of the media, and 3 = perforation of the external elastic membrane to the adventitia. The average injury score for each segment was calculated by dividing the sum of the injury scores by the total number of struts at the examined section. For the evaluation of inflammation scores, neointimal area, and fibrin score with regard to the inflammation score for each individual strut, the grading was as follows: 0 = no inflammatory cells surrounding the strut; 1 = light, noncircumferential lymphohistiocytic infiltrates surrounding the strut; 2 = localized, moderate- to-dense cellular aggregates noncircumferentially surrounding the stent strut; 3 = circumferential dense lymphohistiocytic cell infiltration of the stent strut[24].

    2.9. Immunofluorescence analysis

    Upon completion of flow experiments, the samples were immediately fixed in 10% formaldehyde. Immunofluorescence staining was then performed after blocking with 10% (w/v) bovine serum albumin in PBS at room temperature for 1 h, and then the samples were incubated in 1 : 200 primary antibody (CD34, bs-8996R, Bioss, anti- CD68; Abcam, Cambridge, UK) in a blocking solution at room temperature for 1 h. Sections were then washed 3 times in PBS for 5 min and exposed to fluorescent-labeled secondary antibodies (goat anti-rabbit/ rat 546/488) diluted in blocking buffer to 1 : 250/500 for 40 min at room temperature in a humidified chamber with shaking. After 3 PBS washes for 5 min each, the slides were incubated with 4’,6-diamidino- 2-phenylindole at 1 : 1000 in distilled water for 10 min, washed in PBS in a Coplin jar for 5 min, dried, and covered with coverslip and sealed with nail polish. The immunostained sections were imaged using a Nikon microscope (ECLIPSE 80i; Nikon, Japan).

    2.10. Statistical analysis

    Statistical analysis was performed using commercially available software (SPSS version 15; SPSS Inc., Chicago, IL, USA). Data were presented as mean ± standard deviation. Unpaired Student’s t test was used to compare between the 2 stent groups. A P value of 0.05 was considered statistically significant.

    3. Results & Discussion

    3.1. Surface morphology of the stent surface

    The surface morphology that resulted from each coating step was investigated using a SEM. The stent surface morphologies of the SPS and PSS groups are shown in Figure 2a,b and Figure 2c,d, respectively. The surface of the stents was very smooth and uniform, and no crack or webbing was observed between struts.

    According to SEM image, it is possible to know the difference between the SEM measurement results of PSS and SPS. The concept of electrospinning coating method was used to enhance the adhesion between peptide and Co-Cr. It can be confirmed by the smoothness of the SEM. As a result, it was possible to prevent cracking and peeling of the backup layer between the drug-eluting stent and the drug storage layer. Also, organic solvents that can cause cytotoxicity in electrospinning are completely volatile, so they evaporate completely[25]. Acetonitrile was used as the coating solvent for the peptide, and THF was used for sirolimus. Depending on the secondary coating solvent, the surface roughness varies[26]. Although only substances are different, all other conditions are the same, but due to problems like solubility, such conditions are not established and additional supplementation is required.

    3.2. In vitro drug release of DDES

    The total coating amount of sirolimus and peptide was 106 and 104 μg/18mm, respectively, which is similar to that of the commercial sirolimus- eluting stent (180 μg/18 mm)[27]. SPS group and PSS group showed the same elution pattern, and it was confirmed that sirolimus was eluted after peptide was eluted. In this comparison, it was confirmed that 60% of the peptide and sirolimus was eluted on the 3rd day (Figure 3).

    To investigate drug release kinetics, a device designed to mimic the circulation system of the body was used in this study. It was confirmed that 60% of the peptide was eluted on the 3rd day. The dissolution rate confirmed that the peptide was eluted earlier than sirolimus. According to this study, the dopamine synthetic peptide progressed faster than using sirolimus and PLGA. Graph confirmed that peptide elution was promoted in both groups. This is due to the difference in polymer elution. Also, the peptide has hydrophilicity, sirolimus is hydrophobic, which also has an effect.

    3.3. Histopathological analysis

    In this animal study, the coated stents (SPS and PSS) were randomly introduced into the left anterior descending artery and left circumflex artery of the pigs (n = 10). The mortality rate in this study was 0%. The stent-to-artery ratio was defined as the proportion of the stent diameter divided by the arterial luminal diameter. Four weeks after stent implantation, vessels surrounding the stents were harvested and subjected to histopathological analysis. The images from histopathological analysis are shown in Figure 4. There were no significant differences in the injury score (SPS S 2.8 ± 0.17 and PSS 2.6 ± 0.70), fibrin score (SPS 2.2 ± 0.67 and PSS 2.2 ± 1.05), or scores of the inflammation parameters (SPS 2.2 ± 0.76 and PSS 2.1 ± 1.13). However, there were significant differences in the LA (SPS 2.1 ± 0.01 mm2 and PSS 2.8 ± 0.01 mm2), IELarea (SPS 3.8±0.02 mm2 and PSS 4.2±0.63 mm2), and percentage area of stenosis(SPS 43.4±0.01% and PSS 33.8±0.31%) (Figure 5).

    The two groups of stents (SPS and PSS) were transplanted into porcine coronary arteries. There were no significant differences in the injury score, fibrin score, and inflammation scores among the groups at 4 weeks post-implantation (Figure 5). However, the percentage area of stenosis was lower with PSS than with SPS. In this study conducted animal experiments on stents that inhibit restenosis when using WKYMVm and sirolimus to improve re-endothelialization.

    3.4. Immunofluorescence

    Four weeks after stent implantation, the vessels surrounding the stents were isolated and sectioned. Immunofluorescence for investigating re-endothelialization and inflammation was performed using CD34 and CD68 antibodies. CD34 and CD68 stained with a consecutive linear pattern in the SPS and PSS groups, suggesting that WKYMVm promoted endothelialization and reduced the inflammation induced by sirolimus (Figure 5).

    In this study, the order of coating of the two drugs was different, and PSS and SPS which want to confirm the difference in the displayed animal experiment were compared and analyzed. PSS was more effective then SPS in terms of endothelialization and neointima formation without significant inflammation. CD34 antibody was used as a marker for endothelial cells and CD68 as an inflammation marker, and CD34 and CD68 staining showed a consecutive linear pattern in the two groups, suggesting that SPS and PSS were similar. To identify the cells around the stent struts, immunofluorescence analysis was performed to investigate whether endothelialization of the stent lumen occurred. We confirmed again that endothelialization was promoted based on the positive staining of endothelial cells with the CD34 antibody. As shown in Figure 5, it was confirmed that re-endothelialization was achieved in both groups owing to the influence of the peptide (green in PSS and SPS). However, in immunofluorescence staining, the green-expressed cell layer was found to becaused by reendo-thelialization in the PSS group because it was stained uniformed at PSS CD34. It is predicted that WKYMVm peptide is eluted at the site of direct contact with the inner wall of the blood vessel, and the effect of WKYMVm peptide is given more and the result is obtained. Formyl peptide receptor (FPR) has been reported to play an important role in plasma reactions and vascular-genetic responses. The WKYMVm peptide used in this study was confirmed with a novel peptide that activates FPR-2 expressed in various cell types such as phagocytes, fibroblasts, and endothelial cells[28]. Our results demonstrate that sustained release of WKYMVm peptide from SPS, PSS promotes angiogenic stimulation. The presence or absence of inflammation was determined using CD68 antibody. As a result, the inflammatory findings were found to be not significant in both groups (red in PSS CD68 and PPS CD68). This showed the role of sirolimus in cell proliferation.

    4. Conclusion

    In previous studies, the results of histological analysis by animal studies showed that WKYMVm promotes endothelial cell formation, showing a continuous linear pattern in HA-Pep and Pep/SRL groups. These results demonstrate that the WKYMVm coating could promote endothelial healing, and consecutive coatings of WKYMVm and sirolimus onto bare-metal stents have a potential role in re-endothelialization and neointimal suppression. overcome these problems the use of two drugs requires research on the placement of drug coatings. We synthesized dopamine into WKYMVm, a synthesized natural polymer, for the purpose of enhancing biocompatibility and controlling elution. WKYMVm and sirolimus were coated onto our own custom-designed CNUH stent in consecutive order. Then, we investigated the effect of coating the stent with WKYMVm-dopamine and sirolimus in the reverse order. The sequence of drug coating onto BMS may affect the various physio-biological properties of stents, such as the surface morphology, drug release kinetics, and drug release time point. In this animal study, it was confirmed that endothelialization was promoted without being significantly affected by the coating order (SPS or PSS). The sequence of drug and peptide coating may affect development of restenosis and PSS was effective in the prevention of restenosis compared in SPS. These results suggest that the drug-coating sequence is a considerable factor in obtaining the desired results. PSS was more effective in the prevention of neointimal proliferation compared with SPS.

    Acknowledgement

    This research was supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (grant number: HI16C2319) and supported by the Jellanamdo, Korea, under Regional Specialized Industry Development Program of Next-generation stent innovative processing advance technology support project (R&D, B0080621000341).

    Figures

    ACE-31-5-502_F1.gif
    PSS, stent with peptide as primary coating and sirolimus as secondary coating. SPS, stent with sirolimus as primary coating and peptide as secondary coating. Red: Sirolimus and PLGA, Blue: WKYMVm-dopamine.
    ACE-31-5-502_F2.gif
    Surface morphologies of the stents. Peptide- then sirolimuscoated stent, magnification (PSS): × 100 (a) and × 100 (b). Sirolimus-then peptide-coated stent, magnification (SPS): × 100 (c) and × 1k (d).
    ACE-31-5-502_F3.gif
    In vitro cumulative release kinetics of drugs from stents. Stents were immersed with cells in phosphate-buffered saline (PBS). The amount of drugs released in PBS at designated time points was measured using an ultraviolet-visible spectrophotometer. Peptide- then sirolimus-coated stent (PSS) (a), Sirolimus- then peptide-coated stent (SPS) (b).
    ACE-31-5-502_F4.gif
    Carstairs’ staining (in low- and high-power fields, × 20 and × 200) of fibrin infiltration in the implanted Peptide- then sirolimuscoated stent (PSS: a, b) and Sirolimus- then peptide-coated stent (SPS: c, d).
    ACE-31-5-502_F5.gif
    Morphometric analysis of histological sections. Data are mean ± standard deviation (n = 10). ***P < 0.001 (NS, not significant). PSS, stent with peptide as primary coating and sirolimus as secondary coating. SPS, stent with sirolimus as primary coating and peptide as secondary coating.
    ACE-31-5-502_F6.gif
    Representative images of histopathological analysis. Four weeks after transplantation, blood vessels surrounding the peptidethen sirolimus-coated (a, b) and sirolimus- then peptide-coated stents (c, d) were isolated and subjected toimmunofluorescence analysis. CD34 staining (a, c), CD68 staining (b, d).

    Tables

    References

    1. A. Tan, Y. Farhatnia, A. de Mel, J. Rajadas, M. S. Alavijeh, and A. M. Seifalian, Inception to actualization: Next generation coronary stent coatings incorporating nanotechnology, J. Biotechnol., 164, 151-170 (2013).
    2. H. Chang, K. F. Ren, H. Zhang, J. L. Wang, B. L. Wang, and J. Ji, The (PrS/HGF-pDNA) multilayer films for gene-eluting stent coating: Gene-protecting, anticoagulation, antibacterial properties, and in vivo antirestenosis evaluation, J. Biomed. Mater. Res. B Appl. Biomater., 103, 430-439 (2015).
    3. X. Ma, S. Oyamada, F. Gao, T. Wu, M. P. Robich, H. Wu, X. Wang, B. Buchholz, S. McCarthy, Z. Gu, C. F. Bianchi, F. W. Sellke, and R. Laham, Paclitaxel/sirolimus combination coated drug-eluting stent: In vitro and in vivo drug release studies, J. Pharm. Biomed. Anal., 54, 807-811 (2011).
    4. Y. Huang, S. S. Venkatraman, F. Y. Boey, E. M. Lahti, P. R. Umashankar, M. Mohanty, S. Arumugam, L. Khanolkar, and S. Vaishnav, In vitro and in vivo performance of a dual drug-eluting stent (DDES), Biomaterials, 31, 4382-4391, (2010).
    5. A. Kivela and J. Hartikainen, Restenosis related to percutaneous coronary intervention has been solved?, Ann. Med., 38, 173-187 (2006).
    6. Q. Lin, X. Ding, F. Qiu, X. Song, G. Fu, and J. Ji, In situ endothelialization of Intravascular stents coated with an anti-CD34 antibody functionalized heparin-collagen multilayer, Biomaterials, 31, 4017-4025 (2010).
    7. J. J. Kleinedler, J. D. Foley, E. A. Orchard, and T. R. Dugas, Novel nanocomposite stent coating releasing resveratrol and quercetin reduces neointimal hyperplasia and promotes re-endothelialization, J. Control. Release, 159, 27-33 (2012).
    8. M. Shuchman, Trading restenosis for thrombosis? New questions about drug-eluting stents, N. Engl. J. Med., 355, 1949-1952 (2006).
    9. H. Tang, Q. Wang, X. Wang, J. Zhou, M. Zhu, T. Qiao, C. Liu, C. Mao, and M. Zhou, Effect of a Novel stent on re-endothelialization, platelet adhesion, and neointimal formation, J. Atheroscler. Thromb., 23, 67-80 (2016).
    10. G. Nakazawa, J. F. Granada, C. L. Alviar, A. Tellez, G. L. Kaluza, M. Y. Guilhermier, S. Parker, S. M. Rowland, F. D. Kolodgie, and M. B. Leon, R. Virmani, Anti-CD34 antibodies immobilized on the surface of sirolimus-eluting stents enhance stent endothelialization, JACC Cardiovasc. Interv., 3, 68-75 (2010).
    11. M. R. Bennett, Vascular pathology as a result of drug-eluting stents, Heart, 93, 895-896 (2007).
    12. P. Roopmani, S. Satheesh, D. C. Raj, and U. M. Krishnan, Development of dual drug eluting cardiovascular stent with ultrathin flexible poly(l-lactide-co-caprolactone) coating, ACS Biomater. Sci. Eng., 5(6), 2899-2915 (2019).
    13. M. Yu, B. Xu, D.E. Kandzari, Y. Wu, H. Yan, J. Chen, J. Qian, S. Qiao, Y. Yang, and R. L. Gao, First report of a novel polymer- free dual-drug eluting stent in de novo coronary artery disease: Results of the first in human BICARE trial, Catheter Cardiovasc. Interv., 83, 405-411 (2014).
    14. C. M. Matter, I. Rozenberg, A. Jaschko, H. Greutert, D. J. Kurz, S. Wnendt, B. Kuttler, H. Joch, J. Grunenfelder, G. Zund, F. C. Tanner, and T. F. Luscher, Effects of tacrolimus or sirolimus on proliferation of vascular smooth muscle and endothelial cells, J. Cardiovasc. Pharmacol., 48, 286-292 (2006).
    15. A. Curcio, D. Torella, and C. Indolfi, Mechanisms of smooth muscle cell proliferation and endothelial regeneration after vascular injury and stenting: approach to therapy, Circ. J., 75, 1287-1296 (2011).
    16. Y. Le, W. Gong, B. Li, N. M. Dunlop, W. Shen, S. B. Su, R. D. Ye, and J. M. Wang, Utilization of two seven-transmembrane, G protein-coupled receptors, formyl peptide receptor-like 1 and formyl peptide receptor, by the synthetic hexapeptide WKYMVm for human phagocyte activation, J. Immunol., 163, 6777-6784 (1999).
    17. J. K. Seo, S. Y. Choi, Y. Kim, S. H. Baek, K. T. Kim, C. B. Chae, J. D. Lambeth, P. G. Suh, and S. H. Ryu, A peptide with unique receptor specificity: Stimulation of phosphoinositide hydrolysis and induction of superoxide generation in human neutrophils, J. Immunol., 158, 1895-1901 (1997).
    18. S. C. Heo, Y. W. Kwon, I. H. Jang, G. O. Jeong, J. W. Yoon, C. D. Kim, S. M. Kwon, Y. S. Bae, and J. H. Kim, WKYMVm-induced activation of formyl peptide receptor 2 stimulates ischemic neovasculogenesis by promoting homing of endothelial colony-forming cells, Stem Cells, 32, 779-790 (2014).
    19. E. J. Jang, I. H. Bae, D. S. Park, S. Y. Lee, K. S. Lim, J. K. Park, J. W. Shim, D. S. Sim, and M. H. Jeong, Effect of a novel peptide, WKYMVm- and sirolimus-coated stent on re-endothelialization and anti-restenosis, J. Mater. Sci. Mater. Med., 26, 251 (2015).
    20. S. Y. Lee, I. H. Bae, D. S. Park, E. J. Jang, J. W. Shim, K. S. Lim, J. K. Park, D. S. Sim, and M. H. Jeong, Comparison of dextran- based sirolimus-eluting stents and PLA-based sirolimus-eluting stents in vitro and in vivo, J. Biomed. Mater. Res. A, 105, 301-310 (2017).
    21. I. H. Bae, K. S. Lim, J. K. Park, D. S. Park, S. Y. Lee, E. J. Jang, M. S. Ji, D. S. Sim, Y. J. Hong, Y. Ahn, J. C. Park, J. G. Cho, J. C. Kang, I. S. Kim, J. W. Nah, and M. H. Jeong, Mechanical behavior and in vivo properties of newly designed bare metal stent for enhanced flexibility, J. Ind. Eng. Chem., 21, 1295-1300 (2015).
    22. P. Buszman, S. Trznadel, A. Zurakowski, K. Milewski, L. Kinasz, M. Krol, and M. Kondys, Prospective registry evaluating safety and efficacy of cobalt-chromium stent implantation in patients with de novo coronary lesions, Kardiol. Pol., 65, 1041-1048 (2007).
    23. National Research Council (U.S.), Committee for the Update of the Guide for the Care and Use of Laboratory Animals., Institute for Laboratory Animal Research (U.S.), National Academies Press (U.S.), Guide for the care and use of laboratory animals, National Academies Press,, Washington, D.C., 2011, pp. xxv, p. 220.
    24. R. S. Schwartz, K. C. Huber, J. G. Murphy, W. D. Edwards, A. R. Camrud, R. E. Vlietstra, and D. R. Holmes, Restenosis and the proportional neointimal response to coronary artery injury: Results in a porcine model, J. Am. Coll. Cardiol., 19, 267-274 (1992).
    25. M. H. Chen, P. C. Liang, K. C. Chang, J. Y. Huang, Y. T. Chang, F. Y. Chang, J. M. Wong, and F. H. Lin, Prototype of biliary drug-eluting stent with photodynamic and chemotherapy using electrospinning, Biomed. Eng. Online, 13, 118 (2014).
    26. W. Ye, Q. Shi, J. W. Hou, J. Jin, Q. F. Fan, S. C. Wong, X. D. Xu, and J. H. Yin, Superhydrophobic coating of elastomer on different substrates using a liquid template to construct a biocompatible and antibacterial surface, J. Mater. Chem. B, 2, 7186-7191(2014).
    27. A. W. Heldman, L. Cheng, G. M. Jenkins, P. F. Heller, D. W. Kim, M. Ware, Jr., C. Nater, R. H. Hruban, B. Rezai, B. S. Abella, K. E. Bunge, J. L. Kinsella, S. J. Sollott, E. G. Lakatta, J. A. Brinker, W. L. Hunter, and J. P. Froehlich, Paclitaxel stent coating inhibits neointimal hyperplasia at 4 weeks in a porcine model of coronary restenosis, Circulation, 103, 2289-2295 (2001).
    28. Y. H. Choi, S. C. Heo, Y. W. Kwon, H. D. Kim, S. H. Kim, I. H. Jang, J. H. Kim, and N. S. Hwang, Injectable PLGA microspheres encapsulating WKYMVM peptide for neovascularization, Acta Biomater., 25, 76-85 (2015).
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