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Mandal AP, Mandal PK. Specific and nonspecific binding of drug eluted from a half-embedded stent in presence of atherosclerotic plaque. Comput Methods Biomech Biomed Engin 2021; 25:922-935. [PMID: 34615426 DOI: 10.1080/10255842.2021.1986813] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
This study is dealt with the two-phase binding (specific and nonspecific) of drug eluted from a half- embedded drug-eluting stent in presence of atherosclerotic plaque. The specific binding due to the interaction of drug molecules with specific receptors and nonspecific binding caused by the trapping of drug in the extra-cellular matrix have been paid due attention. An idealised wall consisting of a plaque and a healthy tissue region has been considered. Moreover, a Dirichlet release condition is imposed on the strut surface. In this investigation, a two-dimensional model governing drug transport and its two-phase binding in cylindrical polar coordinate system has been solved numerically by a finite-difference method. Our simulation predicts that plaque behaves like a physical barrier in two types of the binding process and there is an inverse relationship between bound drug concentration and plaque thickness. Simulations show that a single peak profile of drug is noted when the struts are situated one-strut radius apart and as the inter-strut distance increases, the peak concentration falls and distinct peak profiles over each strut are visualised. The model also reveals that in the region downstream of a strut, the concentration of both bound drug forms in the plaque and healthy regions increases, and eventually, the saturation length of binding sites increases. Predicted results show for smaller Damköhler number, the rapid saturation of binding sites takes place and the stent having thinner strut may perform well in terms of effectiveness as well as efficacy in the stent-based delivery.
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Affiliation(s)
- Akash Pradip Mandal
- Department of Mathematics, Ananda Chandra College, North Bengal University, Jalpaiguri, West Bengal, India
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2
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Song J, Kouidri S, Bakir F. Review on the numerical investigations of mass transfer from drug eluting stent. Biocybern Biomed Eng 2021. [DOI: 10.1016/j.bbe.2021.06.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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3
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Saha R. A Computational Approach for Stent Elution Rate Determined Specific Drug Binding and Receptor-mediated Effects in Arterial Tissue. JOURNAL OF EXPLORATORY RESEARCH IN PHARMACOLOGY 2018; 3:105-118. [DOI: 10.14218/jerp.2018.00018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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4
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Saha R, Mandal PK. Modelling Time-dependent Release Kinetics in Stent-based Delivery. JOURNAL OF EXPLORATORY RESEARCH IN PHARMACOLOGY 2018; 3:61-70. [DOI: 10.14218/jerp.2018.00001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Mandal AP, Mandal PK. Distribution and retention of drug through an idealised atherosclerotic plaque eluted from a half-embedded stent. ACTA ACUST UNITED AC 2017. [DOI: 10.1007/s40435-017-0372-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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6
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Tzafriri AR, Garcia-Polite F, Zani B, Stanley J, Muraj B, Knutson J, Kohler R, Markham P, Nikanorov A, Edelman ER. Calcified plaque modification alters local drug delivery in the treatment of peripheral atherosclerosis. J Control Release 2017; 264:203-210. [PMID: 28867375 DOI: 10.1016/j.jconrel.2017.08.037] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 08/07/2017] [Accepted: 08/29/2017] [Indexed: 12/01/2022]
Abstract
BACKGROUND Calcific atherosclerosis is a major challenge to intraluminal drug delivery in peripheral artery disease (PAD). OBJECTIVES We evaluated the effects of orbital atherectomy on intraluminal paclitaxel delivery to human peripheral arteries with substantial calcified plaque. METHODS Diagnostic angiography and 3-D rotational imaging of five fresh human lower limbs revealed calcification in all main arteries. The proximal or distal segment of each artery was treated using an orbital atherectomy system (OAS) under simulated blood flow and fluoroscopy. Explanted arterial segments underwent either histomorphometric assessment of effect or tracking of 14C-labeled or fluorescent-labeled paclitaxel. Radiolabeled drug quantified bulk delivery and fluorescent label established penetration of drug over finer spatial domain in serial microscopic sections. Results were interpreted using a mathematical model of binding-diffusion mediated arterial drug distribution. RESULTS Lesion composition affected paclitaxel absorption and distribution in cadaveric human peripheral arteries. Pretreatment imaging calcium scores in control femoropopliteal arterial segments correlated with a log-linear decline in the bulk absorption rate-constant of 14C-labeled, declining 5.5-fold per calcified quadrant (p=0.05, n=7). Compared to controls, OAS-treated femoropopliteal segments exhibited 180μm thinner intima (p<0.001), 45% less plaque calcification, and 2 log orders higher paclitaxel bulk absorption rate-constants. Correspondingly, fluorescent paclitaxel penetrated deeper in OAS-treated femoropopliteal segments compared to controls, due to a 70% increase in diffusivity (p<0.001). CONCLUSIONS These data illustrate that calcified plaque limited intravascular drug delivery, and controlled OAS treatment of calcific plaques resulted in greater drug permeability and improved adjunct drug delivery to diseased arteries.
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Affiliation(s)
- Abraham R Tzafriri
- CBSET Inc., 500 Shire Way, Lexington, MA, USA; IMES, MIT, 77 Massachusetts Avenue, Cambridge, MA, USA.
| | - Fernando Garcia-Polite
- CBSET Inc., 500 Shire Way, Lexington, MA, USA; IMES, MIT, 77 Massachusetts Avenue, Cambridge, MA, USA
| | - Brett Zani
- CBSET Inc., 500 Shire Way, Lexington, MA, USA
| | | | - Benny Muraj
- CBSET Inc., 500 Shire Way, Lexington, MA, USA
| | - Jennifer Knutson
- CBSET Inc., 500 Shire Way, Lexington, MA, USA; Cardiovascular Systems, Inc., 1225 Old Hwy 8NW, Saint Paul, MN, USA
| | - Robert Kohler
- Cardiovascular Systems, Inc., 1225 Old Hwy 8NW, Saint Paul, MN, USA
| | | | | | - Elazer R Edelman
- IMES, MIT, 77 Massachusetts Avenue, Cambridge, MA, USA; Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
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Abstract
First-generation drug-eluting stents significantly improved treatment of coronary disease, decreasing rates of revascularization. This was offset by high rates of late adverse events, driven primarily by stent thrombosis. Research and design improvements of individual DES platform components led to next-generation devices with superior clinical safety and efficacy profiles compared with bare-metal stents and first-generation drug-eluting stents. These design improvements and features are explored, and their resulting clinical safety and efficacy reviewed, focusing on platforms approved by the Food and Drug Administration currently widely used in the United States.
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Affiliation(s)
- Ramon A Partida
- Division of Cardiology, Department of Medicine, Massachusetts General Hospital, 55 Fruit Street, GRB-800 Boston, MA 02114, USA; Institute for Medical Engineering and Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, E25-438, Cambridge, MA 02139, USA; Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA
| | - Robert W Yeh
- Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA; Department of Medicine, Smith Center for Outcomes Research in Cardiology, CardioVascular Institute, Beth Israel Medical Center, 330 Brookline Avenue, Baker 4, Boston, MA 02215, USA; Harvard Clinical Research Institute, Boston, MA, USA.
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Abstract
First-generation drug-eluting stents significantly improved treatment of coronary disease, decreasing rates of revascularization. This was offset by high rates of late adverse events, driven primarily by stent thrombosis. Research and design improvements of individual DES platform components led to next-generation devices with superior clinical safety and efficacy profiles compared with bare-metal stents and first-generation drug-eluting stents. These design improvements and features are explored, and their resulting clinical safety and efficacy reviewed, focusing on platforms approved by the Food and Drug Administration currently widely used in the United States.
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Mandal AP, Mandal PK. Computational Modelling of Three-phase Stent-based Delivery. JOURNAL OF EXPLORATORY RESEARCH IN PHARMACOLOGY 2017; 2:31-40. [DOI: 10.14218/jerp.2017.00001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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10
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Abstract
Delivery of drugs onto arterial targets via endovascular devices commands several principles: dissolution, diffusion, convection, drug binding, barriers to absorption, and interaction between the drug, delivery vehicle, and accepting arterial wall. The understanding of drug delivery in the coronary vasculature is vast; there is ongoing work needed in the peripheral arteries. There are differences that account for some failures of application of coronary technology into the peripheral vascular space. Breakthroughs in peripheral vascular interventional techniques building on current technologies require investigators willing to acknowledge the similarities and differences between these different vascular territories, while developing technologies adapted for peripheral arteries.
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Affiliation(s)
- Jun Li
- Division of Cardiovascular Medicine, Department of Interventional Cardiology, Harrington Heart and Vascular Institute, University Hospitals Cleveland Medical Center, 11000 Euclid Avenue, Cleveland, OH 44106, USA; Department of Medicine, Case Western Reserve University School of Medicine, 2109 Adelbert Road, Cleveland, OH 44106, USA
| | | | - Sandeep M Patel
- Division of Cardiovascular Medicine, Department of Interventional Cardiology, Harrington Heart and Vascular Institute, University Hospitals Cleveland Medical Center, 11000 Euclid Avenue, Cleveland, OH 44106, USA; Department of Medicine, Case Western Reserve University School of Medicine, 2109 Adelbert Road, Cleveland, OH 44106, USA
| | - Sahil A Parikh
- Endovascular Services, Division of Cardiology, Department of Medicine, Center for Interventional Vascular Therapy, Columbia University Medical Center/NY Presbyterian Hospital, Columbia University College of Physicians and Surgeons, 161 Fort Washington Avenue, New York, NY 10032, USA.
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Haeri A, Sadeghian S, Rabbani S, Anvari MS, Ghassemi S, Radfar F, Dadashzadeh S. Effective attenuation of vascular restenosis following local delivery of chitosan decorated sirolimus liposomes. Carbohydr Polym 2017; 157:1461-1469. [DOI: 10.1016/j.carbpol.2016.11.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 10/27/2016] [Accepted: 11/07/2016] [Indexed: 12/11/2022]
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Haeri A, Sadeghian S, Rabbani S, Shirani S, Anvari MS, Dadashzadeh S. Physicochemical characteristics of liposomes are decisive for their antirestenosis efficacy following local delivery. Nanomedicine (Lond) 2016; 12:131-145. [PMID: 27876438 DOI: 10.2217/nnm-2016-0294] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
AIM To develop an ameliorated sirolimus (SIR) liposome for intramural delivery, the effects of various carrier physicochemical parameters on the antirestenosis efficacy were evaluated. MATERIALS & METHODS Different liposomes were prepared, characterized and administered to balloon injured rats (12 animal groups). Their efficacies were investigated using morphometric, immunohistochemical and in vivo computed tomography imaging analyses. RESULTS The antirestenosis efficacy of SIR liposomes decreased in the following order: cationic 100 nm vesicles ≥ cationic 60 nm vesicles > neutral 100 nm vesicles ≥ stealth 100 nm vesicles > anionic 100 nm vesicles. The 100 µg SIR loaded in cationic liposomes showed almost no artery stenosis. CONCLUSION Appropriate modulation of physicochemical characteristics makes it possible to optimize the liposomes for local delivery.
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Affiliation(s)
- Azadeh Haeri
- Department of Pharmaceutics, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Saeed Sadeghian
- Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Shahram Rabbani
- Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Shapour Shirani
- Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Simin Dadashzadeh
- Department of Pharmaceutics, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Pharmaceutical Sciences Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Drug deposition in coronary arteries with overlapping drug-eluting stents. J Control Release 2016; 238:1-9. [PMID: 27432751 DOI: 10.1016/j.jconrel.2016.07.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 07/13/2016] [Accepted: 07/14/2016] [Indexed: 01/20/2023]
Abstract
Drug-eluting stents are accepted as mainstream endovascular therapy, yet concerns for their safety may be under-appreciated. While failure from restenosis has dropped to below 5%, the risk of stent thrombosis and associated mortality remain relatively high. Further optimization of drug release is required to minimize thrombosis risk while maintaining therapeutic dose. The complex three-dimensional geometry of deployed stents together with the combination of diffusive and advective drug transport render an intuitive understanding of the situation exceedingly difficult. In situations such as this, computational modeling has proven essential, helping define the limits of efficacy, determine the mode and mechanism of drug release, and identify alternatives to avoid toxicity. A particularly challenging conformation is encountered in coronary arteries with overlapping stents. To study hemodynamics and drug deposition in such vessels we combined high-resolution, multi-scale ex vivo computed tomography with a flow and mass transfer computational model. This approach ensures high geometric fidelity and precise, simultaneous calculation of blood flow velocity, shear stress and drug distribution. Our calculations show that drug uptake by the arterial tissue is dependent both on the patterns of flow disruption near the wall, as well as on the relative positioning of drug-eluting struts. Overlapping stent struts lead to localized peaks of drug concentration that may increase the risk of thrombosis. Such peaks could be avoided by anisotropic stent structure or asymmetric drug release designed to yield homogeneous drug distribution along the coronary artery and, at the least, suggest that these issues need to remain in the forefront of consideration in clinical practice.
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Mahl A, Dincer Z, Heining P. The Potential of Minipigs in the Development of Anticancer Therapeutics: Species Comparison and Examples of Special Applications. Toxicol Pathol 2015; 44:391-7. [PMID: 26698323 DOI: 10.1177/0192623315619040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Minipigs are increasingly being used as an alternative to dog or monkey in nonclinical safety testing of pharmaceuticals since they share similar anatomical and physiological characteristics to humans. Integrative assessment of pharmacodynamic and pharmacokinetic data sets of drug candidates fromin silico,in vitro, andin vivoinvestigations form the basis for selecting the most relevant nonrodent species for toxicology studies. Developing anticancer therapeutics represents a special challenge for species selection due to their effects on multiple organ systems. The toxicological profile of anticancer drugs can be associated with steep dose-response curves, especially due to dose-limiting toxicity on the alimentary, hematopoietic, and immune systems. Selection of an appropriate species for toxicology studies is of importance to avoid an inappropriately low (without benefit for the late-stage cancer patient) or high clinical starting dose (with a risk of unexpected adverse reactions). Although the minipig has been the preferred species to develop drugs applied topically, it is only rarely used in anticancer drug development compared to dog and monkey. In this context, we discuss the potential of minipigs in anticancer drug development with examples of programs for oral and dermal administration, intravascular application in drug-eluting stents, and local chemotherapy (chemoembolization).
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Affiliation(s)
- Andreas Mahl
- Novartis Institute for Biomedical Research, Preclinical Safety, Basel, Switzerland
| | - Zuhal Dincer
- Novartis Institute for Biomedical Research, Preclinical Safety, Basel, Switzerland
| | - Peter Heining
- Novartis Institute for Biomedical Research, Preclinical Safety, Basel, Switzerland
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Zhu X, Braatz RD. Modeling and analysis of drug-eluting stents with biodegradable PLGA coating: consequences on intravascular drug delivery. J Biomech Eng 2015; 136:1894901. [PMID: 25084767 DOI: 10.1115/1.4028135] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Indexed: 11/08/2022]
Abstract
Increasing interests have been raised toward the potential applications of biodegradable poly(lactic-co-glycolic acid) (PLGA) coatings for drug-eluting stents in order to improve the drug delivery and reduce adverse outcomes in stented arteries in patients. This article presents a mathematical model to describe the integrated processes of drug release in a stent with PLGA coating and subsequent drug delivery, distribution, and drug pharmacokinetics in the arterial wall. The integrated model takes into account the PLGA degradation and erosion, anisotropic drug diffusion in the arterial wall, and reversible drug binding. The model simulations first compare the drug delivery from a biodegradable PLGA coating with that from a biodurable coating, including the drug release profiles in the coating, average arterial drug levels, and arterial drug distribution. Using the model for the PLGA stent coating, the simulations further investigate drug internalization, interstitial fluid flow in the arterial wall, and stent embedment for their impact on drug delivery. Simulation results show that these three factors, while imposing little change in the drug release profiles, can greatly change the average drug concentrations in the arterial wall. In particular, each of the factors leads to significant and yet distinguished alterations in the arterial drug distribution that can potentially influence the treatment outcomes. The detailed integrated model provides insights into the design and evaluation of biodegradable PLGA-coated drug-eluting stents for improved intravascular drug delivery.
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16
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Orlik B, Buszman PP, Krauze A, Gąsior P, Desperak P, Pająk J, Kasperczyk J, Janas A, Jelonek M, Handzlik-Orlik G, Buszman PE, Milewski K. A Nuclear Magnetic Resonance Spectroscopy as a Method for Evaluation of In Vivo Poly-l-Lactide Biodegradation Kinetics From Stent-Polymer Matrices: An Experimental Study Utilizing Porcine Model of In-Stent Restenosis. J Cardiovasc Pharmacol Ther 2015; 21:93-9. [PMID: 25944843 DOI: 10.1177/1074248415583091] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 03/02/2015] [Indexed: 11/17/2022]
Abstract
OBJECTIVES We aimed to comprehensively evaluate poly-lactide polymer degradation and sirolimus release kinetics from a drug-eluting stent matrix in the in vivo setting using a nuclear magnetic resonance (NMR) method. METHODS In 22 domestic swine, 18 biodegradable polymer-only coated stents (BPSs) and 36 biodegradable polymer-coated sirolimus-eluting stents (BP-SES) were implanted in coronary arteries with 115% overstretch. The animals were sacrificed at 1, 3, 7, 14, 28, and 56 days following baseline procedures. Vessel segments with BPS were harvested to evaluate polymer degradation with a NMR method, whereas BP-SES to analyze sirolimus tissue uptake and retention. Additionally, 8 BP-SES were implanted for histological analysis for 90 days of follow-up. RESULTS The NMR showed a gradual absorption of the polymer over the 6 consecutive time points, from 5.48 µg of the polymer on the stent at 1-day follow-up, through 4.33 µg at 3 days, 3.16 µg at 7 days, 2.42 µg at 14 days, 1.92 µg at 28 days to 1.24 µg in the last day of the study. The curve of polymer degradation corresponds well with the pharmacokinetic profile of sirolimus eluted from its surface and measured at identical time points. In histopathology, at 90 days, complete healing and biocompatibility were reported. CONCLUSIONS The utilization of NMR method for BP absorption kinetics evaluation is a useful tool, which may be widely adopted to test other biodegradable implants. Further, it may substantially improve their safety and efficacy by facilitating programmed polymer and drugs elution.
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Affiliation(s)
- Bartłomiej Orlik
- Center for Cardiovascular Research and Development, American Heart of Poland, Katowice, Poland
| | - Piotr P Buszman
- Center for Cardiovascular Research and Development, American Heart of Poland, Katowice, Poland Third Clinical Department of Cardiology, Silesian Center for Heart Diseases, Zabrze, Poland
| | - Agata Krauze
- Center for Cardiovascular Research and Development, American Heart of Poland, Katowice, Poland
| | - Paweł Gąsior
- Center for Cardiovascular Research and Development, American Heart of Poland, Katowice, Poland
| | - Piotr Desperak
- Center for Cardiovascular Research and Development, American Heart of Poland, Katowice, Poland
| | - Jacek Pająk
- Department of Histopathology, Medical University of Silesia, Katowice, Poland
| | - Janusz Kasperczyk
- Center of Polymer and Carbon Materials, Polish Academy of Sciences, Zabrze, Poland
| | - Adam Janas
- Center for Cardiovascular Research and Development, American Heart of Poland, Katowice, Poland
| | - Michał Jelonek
- Center for Cardiovascular Research and Development, American Heart of Poland, Katowice, Poland
| | - Gabriela Handzlik-Orlik
- Center for Cardiovascular Research and Development, American Heart of Poland, Katowice, Poland
| | - Paweł E Buszman
- Center for Cardiovascular Research and Development, American Heart of Poland, Katowice, Poland
| | - Krzysztof Milewski
- Center for Cardiovascular Research and Development, American Heart of Poland, Katowice, Poland
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Numerical modelling of the physical factors that affect mass transport in the vasculature at early time periods. Med Eng Phys 2014; 36:308-17. [PMID: 24462324 DOI: 10.1016/j.medengphy.2013.11.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 10/11/2013] [Accepted: 11/20/2013] [Indexed: 11/21/2022]
Abstract
Coronary artery disease results in blockages or narrowing of the artery lumen. Drug eluting stents were developed to replace bare metal stents in an effort to combat re-blocking of the lumen. A key element in determining the therapeutic success of a drug eluting stent is an in-depth understanding of the physical factors that affect mass transport of the drug into the arterial wall, over early time periods. The numerical models developed within this study focus on assessing the influence of a host of physical factors that either facilitate or impede therapeutic drug delivery into the arterial wall from the unit cell of an idealised stent. This study demonstrates that model reduction strategies to 2D and 1D can still adequately represent a 3D curved arterial wall and strut polymer coating, respectively, using an idealistic stent geometry. It was shown that the level of strut compression can have a significant impact on therapeutic drug delivery in the arterial wall.
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Denny WJ, Walsh MT. Numerical modelling of mass transport in an arterial wall with anisotropic transport properties. J Biomech 2014; 47:168-77. [DOI: 10.1016/j.jbiomech.2013.09.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2013] [Revised: 08/28/2013] [Accepted: 09/18/2013] [Indexed: 10/26/2022]
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O'Connell BM, Cunnane EM, Denny WJ, Carroll GT, Walsh MT. Improving smooth muscle cell exposure to drugs from drug-eluting stents at early time points: a variable compression approach. Biomech Model Mechanobiol 2013; 13:771-81. [PMID: 24101254 DOI: 10.1007/s10237-013-0533-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 09/22/2013] [Indexed: 11/29/2022]
Abstract
The emergence of drug-eluting stents (DES) as a viable replacement for bare metal stenting has led to a significant decrease in the incidence of clinical restenosis. This is due to the transport of anti-restenotic drugs from within the polymer coating of a DES into the artery wall which arrests the cell cycle before restenosis can occur. The efficacy of DES is still under close scrutiny in the medical field as many issues regarding the effectiveness of DES drug transport in vivo still exist. One such issue, that has received less attention, is the limiting effect that stent strut compression has on the transport of drug species in the artery wall. Once the artery wall is compressed, the stents ability to transfer drug species into the arterial wall can be reduced. This leads to a reduction in the spatial therapeutic transfer of drug species to binding sites within the arterial wall. This paper investigates the concept of idealised variable compression as a means of demonstrating how such a stent design approach could improve the spatial delivery of drug species in the arterial wall. The study focused on assessing how the trends in concentration levels changed as a result of artery wall compression. Five idealised stent designs were created with a combination of thick struts that provide the necessary compression to restore luminal patency and thin uncompressive struts that improve the transport of drugs therein. By conducting numerical simulations of diffusive mass transport, this study found that the use of uncompressive struts results in a more uniform spatial distribution of drug species in the arterial wall.
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Affiliation(s)
- Barry M O'Connell
- Centre for Applied Biomedical Engineering (CABER), Department of Mechanical, Aeronautical and Biomedical Engineering and The Materials and Surface Science Institute, University of Limerick, Limerick, Ireland
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Webster M, Harding S, McClean D, Jaffe W, Ormiston J, Aitken A, Watson T. First-in-human evaluation of a sirolimus-eluting coronary stent on an integrated delivery system: the DIRECT study. EUROINTERVENTION 2013; 9:46-53. [DOI: 10.4244/eijv9i1a8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Denny WJ, O'Connell BM, Milroy J, Walsh MT. An analysis of three dimensional diffusion in a representative arterial wall mass transport model. Ann Biomed Eng 2012; 41:1062-73. [PMID: 23269495 DOI: 10.1007/s10439-012-0730-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2012] [Accepted: 12/18/2012] [Indexed: 11/29/2022]
Abstract
The development and use of drug eluting stents has brought about significant improvements in reducing in-stent restenosis, however, their long term presence in the artery is still under examination due to restenosis reoccurring. Current studies focus mainly on stent design, coatings and deployment techniques but few studies address the issue of the physics of three dimensional mass transport in the artery wall. There is a dearth of adequate validated numerical mass transport models that simulate the physics of diffusion dominated drug transport in the artery wall whilst under compression. A novel experimental setup used in a previous study was adapted and an expansion of that research was carried out to validate the physics of three dimensional diffusive mass transport into a compressed porous media. This study developed a more sensitive method for measuring the concentration of the species of interest. It revalidated mass transport in the radial direction and presented results which highlight the need for an evaluation of the governing equation for transient diffusive mass transport in a porous media, in its current form, to be carried out.
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Affiliation(s)
- William J Denny
- Centre for Applied Biomedical Engineering Research (CABER), Department of Mechanical, Aeronautical and Biomedical Engineering and Materials and Surface Science Institute, University of Limerick, Limerick, Ireland
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Morlacchi S, Migliavacca F. Modeling stented coronary arteries: where we are, where to go. Ann Biomed Eng 2012; 41:1428-44. [PMID: 23090621 DOI: 10.1007/s10439-012-0681-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 10/16/2012] [Indexed: 01/09/2023]
Abstract
In the last two decades, numerical models have become well-recognized and widely adopted tools to investigate stenting procedures. Due to limited computational resources and modeling capabilities, early numerical studies only involved simplified cases and idealized stented arteries. Nowadays, increased computational power allows for numerical models to meet clinical needs and include more complex cases such as the implantation of multiple stents in bifurcations or curved vessels. Interesting progresses have been made in the numerical modeling of stenting procedures both from a structural and a fluid dynamics points of view. Moreover, in the drug eluting stents era, new insights on drug elution capabilities are becoming essential in the stent development. Lastly, image-based methods able to reconstruct realistic geometries from medical images have been proposed in the recent literature aiming to better describe the peculiar anatomical features of coronary vessels and increase the accuracy of the numerical models. In this light, this review provides a comprehensive analysis of the current state-of-the-art in this research area, discussing the main methodological advances and remarkable results drawn from a number of significant studies.
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Affiliation(s)
- Stefano Morlacchi
- Laboratory of Biological Structure Mechanics, Structural Engineering Department, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milan, Italy.
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Cutrì E, Zunino P, Morlacchi S, Chiastra C, Migliavacca F. Drug delivery patterns for different stenting techniques in coronary bifurcations: a comparative computational study. Biomech Model Mechanobiol 2012; 12:657-69. [DOI: 10.1007/s10237-012-0432-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 08/14/2012] [Indexed: 11/29/2022]
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24
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Tzafriri AR, Groothuis A, Price GS, Edelman ER. Stent elution rate determines drug deposition and receptor-mediated effects. J Control Release 2012; 161:918-26. [PMID: 22642931 DOI: 10.1016/j.jconrel.2012.05.039] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 05/16/2012] [Accepted: 05/19/2012] [Indexed: 10/28/2022]
Abstract
Drug eluting stent designs abound and yet the dependence of efficacy on drug dose and elution duration remains unclear. We examined these issues within a mathematical framework of arterial drug distribution and receptor binding following stent elution. Model predictions that tissue content linearly tracks stent elution rate were validated in porcine coronary artery sirolimus-eluting stents implants. Arterial content varied for stent types, progressively declining from its Day 1 peak and tracking with rate-limiting drug elution--near zero-order release was three-fold more efficient at depositing drug in the stented lesion than near first-order release. In vivo data were consistent with an overabundance of non-specific sirolimus-binding sites relative to the specific receptors and to the delivered dose. The implication is that the persistence time of receptor saturation and effect is more sensitive to duration of elution than to eluted amount. Consequently, the eluted amount should be sufficiently high to saturate receptors at the target lesion, but dose escalation alone is an inefficient strategy for prolonging the duration of sirolimus deposition. Moreover, receptor saturating drug doses are predicted to be most efficacious when eluted from stents in a constant zero order fashion as this maximizes the duration of elution and receptor saturation.
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25
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Zhu X, Pack DW, Braatz RD. Modelling intravascular delivery from drug-eluting stents with biodurable coating: investigation of anisotropic vascular drug diffusivity and arterial drug distribution. Comput Methods Biomech Biomed Engin 2012; 17:187-98. [PMID: 22512464 DOI: 10.1080/10255842.2012.672815] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
In-stent restenosis occurs in coronary arteries after implantation of drug-eluting stents with non-uniform restenosis thickness distribution in the artery cross section. Knowledge of the spatio-temporal drug uptake in the arterial wall is useful for investigating restenosis growth but may often be very expensive/difficult to acquire experimentally. In this study, local delivery of a hydrophobic drug from a drug-eluting stent implanted in a coronary artery is mathematically modelled to investigate the drug release and spatio-temporal drug distribution in the arterial wall. The model integrates drug diffusion in the coating and drug diffusion with reversible binding in the arterial wall. The model is solved by the finite volume method for both high and low drug loadings relative to its solubility in the stent coating with varied isotropic-anisotropic vascular drug diffusivities. Drug release profiles in the coating are observed to depend not only on the coating drug diffusivity but also on the properties of the surrounding arterial wall. Time dependencies of the spatially averaged free- and bound-drug levels in the arterial wall on the coating and vascular drug diffusivities are discussed. Anisotropic vascular drug diffusivities result in slightly different average drug levels in the arterial wall but with very different spatial distributions. Higher circumferential vascular diffusivity results in more uniform drug loading in the upper layers and is potentially beneficial in reducing in-stent restenosis. An analytical expression is derived which can be used to determine regions in the arterial with higher free-drug concentration than bound-drug concentration.
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Affiliation(s)
- Xiaoxiang Zhu
- a Department of Chemical Engineering , Massachusetts Institute of Technology , Cambridge , MA 02139 , USA
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26
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Kleinedler JJ, Pjescic I, Bullock KK, Khaliq A, Foley JD, Dugas TR. Arterial pharmacokinetics of red wine polyphenols: implications for novel endovascular therapies targeting restenosis. J Pharm Sci 2012; 101:1917-31. [PMID: 22359273 DOI: 10.1002/jps.23074] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Revised: 12/20/2011] [Accepted: 01/18/2012] [Indexed: 11/12/2022]
Abstract
Drug-eluting stents (DESs) are endovascular devices that provide controlled release of compounds to interfere with restenosis, an adverse outcome of angioplasty characterized by thickening of the arterial wall. Accumulating evidence suggests that arterial pharmacokinetics determine the biological effect and potential toxicity of stent-based therapeutics. The aim of this study was to examine how drug polarity, drug load, and protein binding influence release from a polymer film and distribution within arterial tissue. The transport and safety profile of resveratrol (RESV) and quercetin (QUER), two red wine polyphenols known to interfere with events in the pathogenesis of restenosis, were compared with paclitaxel (Taxol), a lipophilic drug used in DES. In bovine arteries, RESV showed considerable protein binding and arterial kinetics that were found to mimick Taxol. In contrast, the less lipophilic QUER showed limited tissue distribution. Measured diffusivity of RESV and QUER was coupled with a novel computational method for assessment of biphasic drug release kinetics and arterial drug retention profiles. Modeling revealed that drugs associated with high- and low-protein-binding affinity result in markedly distinct arterial drug profiles. These data underscore the importance of arterial partitioning and propagation of drug within arterial tissue in the rational design of DES coatings.
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Affiliation(s)
- James J Kleinedler
- Department of Pharmacology, Toxicology, and Neuroscience, Louisiana State University Health Sciences Center, Shreveport, Louisiana 71103, USA
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27
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Computational models for the in silico analysis of drug delivery from drug-eluting stents. Ther Deliv 2011; 2:1-3. [DOI: 10.4155/tde.10.77] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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28
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Balcells M, Martorell J, Olivé C, Santacana M, Chitalia V, Cardoso AA, Edelman ER. Smooth muscle cells orchestrate the endothelial cell response to flow and injury. Circulation 2010; 121:2192-9. [PMID: 20458015 DOI: 10.1161/circulationaha.109.877282] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Local modulation of vascular mammalian target of rapamycin (mTOR) signaling reduces smooth muscle cell (SMC) proliferation after endovascular interventions but may be associated with endothelial cell (EC) toxicity. The trilaminate vascular architecture juxtaposes ECs and SMCs to enable complex paracrine coregulation but shields SMCs from flow. We hypothesized that flow differentially affects mTOR signaling in ECs and SMCs and that SMCs regulate mTOR in ECs. METHODS AND RESULTS SMCs and/or ECs were exposed to coronary artery flow in a perfusion bioreactor. We demonstrated by flow cytometry, immunofluorescence, and immunoblotting that EC expression of phospho-S6 ribosomal protein (p-S6RP), a downstream target of mTOR, was doubled by flow. Conversely, S6RP in SMCs was growth factor but not flow responsive, and SMCs eliminated the flow sensitivity of ECs. Temsirolimus, a sirolimus analog, eliminated the effect of growth factor on SMCs and of flow on ECs, reducing p-S6RP below basal levels and inhibiting endothelial recovery. EC p-S6RP expression in stented porcine arteries confirmed our in vitro findings: Phosphorylation was greatest in ECs farthest from intact SMCs in metal stented arteries and altogether absent after sirolimus stent elution. CONCLUSIONS The mTOR pathway is activated in ECs in response to luminal flow. SMCs inhibit this flow-induced stimulation of endothelial mTOR pathway. Thus, we now define a novel external stimulus regulating phosphorylation of S6RP and another level of EC-SMC crosstalk. These interactions may explain the impact of local antiproliferative delivery that targets SMC proliferation and suggest that future stents integrate design influences on flow and drug effects on their molecular targets.
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MESH Headings
- Animals
- Aorta/physiology
- Arteries/physiology
- Arteries/physiopathology
- Cell Communication/physiology
- Cells, Cultured
- Coronary Vessels/physiology
- Endothelial Cells/metabolism
- Endothelium, Vascular/injuries
- Endothelium, Vascular/pathology
- Endothelium, Vascular/physiopathology
- Humans
- In Vitro Techniques
- Intracellular Signaling Peptides and Proteins/antagonists & inhibitors
- Intracellular Signaling Peptides and Proteins/metabolism
- Muscle, Smooth, Vascular/pathology
- Muscle, Smooth, Vascular/physiopathology
- Myocytes, Smooth Muscle/metabolism
- Phosphorylation
- Protein Serine-Threonine Kinases/antagonists & inhibitors
- Protein Serine-Threonine Kinases/metabolism
- Regional Blood Flow/drug effects
- Regional Blood Flow/physiology
- Ribosomal Protein S6/metabolism
- Signal Transduction
- Sirolimus/analogs & derivatives
- Sirolimus/pharmacology
- Stents/adverse effects
- Swine
- Swine, Miniature
- TOR Serine-Threonine Kinases
- Transcription Factors/metabolism
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Affiliation(s)
- Mercedes Balcells
- Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139, USA.
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29
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Drug release from coronary eluting stents: A multidomain approach. J Biomech 2010; 43:1580-9. [DOI: 10.1016/j.jbiomech.2010.01.033] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Revised: 11/17/2009] [Accepted: 01/03/2010] [Indexed: 11/23/2022]
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30
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O'Connell BM, McGloughlin TM, Walsh MT. Factors that affect mass transport from drug eluting stents into the artery wall. Biomed Eng Online 2010; 9:15. [PMID: 20214774 PMCID: PMC2854105 DOI: 10.1186/1475-925x-9-15] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Accepted: 03/09/2010] [Indexed: 01/12/2023] Open
Abstract
Coronary artery disease can be treated by implanting a stent into the blocked region of an artery, thus enabling blood perfusion to distal vessels. Minimally invasive procedures of this nature often result in damage to the arterial tissue culminating in the re-blocking of the vessel. In an effort to alleviate this phenomenon, known as restenosis, drug eluting stents were developed. They are similar in composition to a bare metal stent but encompass a coating with therapeutic agents designed to reduce the overly aggressive healing response that contributes to restenosis. There are many variables that can influence the effectiveness of these therapeutic drugs being transported from the stent coating to and within the artery wall, many of which have been analysed and documented by researchers. However, the physical deformation of the artery substructure due to stent expansion, and its influence on a drugs ability to diffuse evenly within the artery wall have been lacking in published work to date. The paper highlights previous approaches adopted by researchers and proposes the addition of porous artery wall deformation to increase model accuracy.
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Affiliation(s)
- Barry M O'Connell
- Centre for Applied Biomedical Engineering Research, Department of Mechanical and Aeronautical Engineering and the Materials and Surface Science Institute, University of Limerick, Limerick, Ireland
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31
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O’Connell BM, Walsh MT. Demonstrating the Influence of Compression on Artery Wall Mass Transport. Ann Biomed Eng 2010; 38:1354-66. [DOI: 10.1007/s10439-010-9914-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Accepted: 01/05/2010] [Indexed: 10/20/2022]
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32
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Kolachalama VB, Levine EG, Edelman ER. Luminal flow amplifies stent-based drug deposition in arterial bifurcations. PLoS One 2009; 4:e8105. [PMID: 19956555 PMCID: PMC2781163 DOI: 10.1371/journal.pone.0008105] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Accepted: 11/04/2009] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Treatment of arterial bifurcation lesions using drug-eluting stents (DES) is now common clinical practice and yet the mechanisms governing drug distribution in these complex morphologies are incompletely understood. It is still not evident how to efficiently determine the efficacy of local drug delivery and quantify zones of excessive drug that are harbingers of vascular toxicity and thrombosis, and areas of depletion that are associated with tissue overgrowth and luminal re-narrowing. METHODS AND RESULTS We constructed two-phase computational models of stent-deployed arterial bifurcations simulating blood flow and drug transport to investigate the factors modulating drug distribution when the main-branch (MB) was treated using a DES. Simulations predicted extensive flow-mediated drug delivery in bifurcated vascular beds where the drug distribution patterns are heterogeneous and sensitive to relative stent position and luminal flow. A single DES in the MB coupled with large retrograde luminal flow on the lateral wall of the side-branch (SB) can provide drug deposition on the SB lumen-wall interface, except when the MB stent is downstream of the SB flow divider. In an even more dramatic fashion, the presence of the SB affects drug distribution in the stented MB. Here fluid mechanic effects play an even greater role than in the SB especially when the DES is across and downstream to the flow divider and in a manner dependent upon the Reynolds number. CONCLUSIONS The flow effects on drug deposition and subsequent uptake from endovascular DES are amplified in bifurcation lesions. When only one branch is stented, a complex interplay occurs - drug deposition in the stented MB is altered by the flow divider imposed by the SB and in the SB by the presence of a DES in the MB. The use of DES in arterial bifurcations requires a complex calculus that balances vascular and stent geometry as well as luminal flow.
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Affiliation(s)
- Vijaya B Kolachalama
- Biomedical Engineering Center, Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America.
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33
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Tzafriri AR, Vukmirovic N, Kolachalama VB, Astafieva I, Edelman ER. Lesion complexity determines arterial drug distribution after local drug delivery. J Control Release 2009; 142:332-8. [PMID: 19925836 DOI: 10.1016/j.jconrel.2009.11.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2009] [Accepted: 11/11/2009] [Indexed: 01/23/2023]
Abstract
Though stents are deployed in diseased arteries drug distribution has only been quantified in intact, non-diseased vessels. We correlated steady-state arterial drug distribution with tissue ultrastructure and composition in abdominal aortae from atherosclerotic human autopsy specimens and rabbits with lesions induced by dietary manipulation and controlled injury. Paclitaxel, everolimus, and sirolimus depositions in the human aortae were maximal in the media and scaled inversely with lipid content. Net tissue paclitaxel and everolimus levels were indistinguishable in mildly injured rabbit arteries independent of diet. Yet, serial sectioning of cryopreserved arterial segments demonstrated a differential transmural deposition pattern that was amplified with disease and correlated with the expression of their intracellular targets, tubulin and FKBP-12. Tubulin distribution and paclitaxel binding increased with vascular injury and macrophage infiltration, and were reduced with lipid content. Sirolimus analogs and their specific binding target FKBP-12 were less sensitive to alterations of diet in mildly injured arteries, presumably reflecting a faster transient response of FKBP-12 to injury. The data demonstrate that disease-induced changes in the distribution of drug-binding proteins and interstitial lipid alter the distribution of these drugs, forcing one to consider how disease might affect the evaluation and efficacy of the local release of these and like compounds.
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Affiliation(s)
- Abraham R Tzafriri
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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34
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Kim HI, Takai M, Konno T, Matsuno R, Ishihara K. Biodegradable polymer films for releasing nanovehicles containing sirolimus. Drug Deliv 2009; 16:183-8. [PMID: 19514979 DOI: 10.1080/10717540902757416] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
To obtain novel biodegradable sirolimus-releasing polymer films that could release nanovehicles incorporating sirolimus, polyester, a water-soluble amphiphilic phospholipid polymer, and sirolimus were blended. The sirolimus-releasing polymer films were characterized by scanning electron microscopy and differential scanning calorimetry. Nanovehicles were formed with the phospholipid polymer chains and could be released from the sirolimus-releasing polymer films. The hydrodynamic diameter of the nanovehicles in phosphate-buffered saline was smaller than 20 nm. The nanovehicles substantially enhanced the carrier-mediated delivery of sirolimus and attenuated its degradation product. This study demonstrates that the delivery of sirolimus was enhanced by nanovehicles released from sirolimus-eluting materials.
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Affiliation(s)
- Hyung Il Kim
- Department of Bioengineering, The University of Tokyo, Japan
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35
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Guo Q, Knight PT, Mather PT. Tailored drug release from biodegradable stent coatings based on hybrid polyurethanes. J Control Release 2009; 137:224-33. [DOI: 10.1016/j.jconrel.2009.04.016] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2008] [Revised: 04/09/2009] [Accepted: 04/10/2009] [Indexed: 10/20/2022]
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36
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Kolachalama VB, Tzafriri AR, Arifin DY, Edelman ER. Luminal flow patterns dictate arterial drug deposition in stent-based delivery. J Control Release 2008; 133:24-30. [PMID: 18926864 DOI: 10.1016/j.jconrel.2008.09.075] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2008] [Revised: 09/09/2008] [Accepted: 09/17/2008] [Indexed: 10/21/2022]
Abstract
Endovascular stents reside in a dynamic flow environment and yet the impact of flow on arterial drug deposition after stent-based delivery is only now emerging. We employed computational fluid dynamic modeling tools to investigate the influence of luminal flow patterns on arterial drug deposition and distribution. Flow imposes recirculation zones distal and proximal to the stent strut that extend the coverage of tissue absorption of eluted drug and induce asymmetry in tissue drug distribution. Our analysis now explains how the disparity in sizes of the two recirculation zones and the asymmetry in drug distribution are determined by a complex interplay of local flow and strut geometry. When temporal periodicity was introduced as a model of pulsatile flow, the net luminal flow served as an index of flow-mediated spatio-temporal tissue drug uptake. Dynamically changing luminal flow patterns are intrinsic to the coronary arterial tree. Coronary drug-eluting stents should be appropriately considered where luminal flow, strut design and pulsatility have direct effects on tissue drug uptake after local delivery.
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Affiliation(s)
- Vijaya B Kolachalama
- Biomedical Engineering Center, Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, USA.
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