1
|
Vascular access animal models used in research. Ann Anat 2019; 225:65-75. [DOI: 10.1016/j.aanat.2019.06.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 06/13/2019] [Accepted: 06/13/2019] [Indexed: 12/22/2022]
|
2
|
Mitsouras D, Tao M, de Vries MR, Trocha K, Miranda OR, Vemula PK, Ding K, Imanzadeh A, Schoen FJ, Karp JM, Ozaki CK, Rybicki FJ. Early animal model evaluation of an implantable contrast agent to enhance magnetic resonance imaging of arterial bypass vein grafts. Acta Radiol 2018; 59:1074-1081. [PMID: 29378421 DOI: 10.1177/0284185117753656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Background Non-invasive monitoring of autologous vein graft (VG) bypass grafts is largely limited to detecting late luminal narrowing. Although magnetic resonance imaging (MRI) delineates vein graft intima, media, and adventitia, which may detect early failure, the scan time required to achieve sufficient resolution is at present impractical. Purpose To study VG visualization enhancement in vivo and delineate whether a covalently attached MRI contrast agent would enable quicker longitudinal imaging of the VG wall. Material and Methods Sixteen 12-week-old male C57BL/6J mice underwent carotid interposition vein grafting. The inferior vena cava of nine donor mice was treated with a gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA)-based contrast agent, with control VGs labeled with a vehicle. T1-weighted (T1W) MRI was performed serially at postoperative weeks 1, 4, 12, and 20. A portion of animals was sacrificed for histopathology following each imaging time point. Results MRI signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were significantly higher for treated VGs in the first three time points (1.73 × higher SNR, P = 0.0006, and 5.83 × higher CNR at the first time point, P = 0.0006). However, MRI signal enhancement decreased consistently in the study period, to 1.29 × higher SNR and 2.64 × higher CNR, by the final time point. There were no apparent differences in graft morphometric analyses in Masson's trichrome-stained sections. Conclusion A MRI contrast agent that binds covalently to the VG wall provides significant increase in T1W MRI signal with no observed adverse effects in a mouse model. Further optimization of the contrast agent to enhance its durability is required.
Collapse
Affiliation(s)
- Dimitrios Mitsouras
- Applied Imaging Science Laboratory, Department of Radiology, Brigham and Women’s Hospital, Boston, MA, USA
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Ming Tao
- Department of Surgery, Brigham and Women’s Hospital, Boston, MA, USA
| | - Margreet R de Vries
- Department of Surgery, Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Kaspar Trocha
- Department of Surgery, Brigham and Women’s Hospital, Boston, MA, USA
| | - Oscar R Miranda
- Harvard Stem Cell Institute, Harvard University, Boston, MA, USA
- Harvard-MIT Division of Health Science and Technology, Department of Medicine, Brigham and Women’s Hospital, Boston, MA, USA
| | - Praveen Kumar Vemula
- Harvard Stem Cell Institute, Harvard University, Boston, MA, USA
- Harvard-MIT Division of Health Science and Technology, Department of Medicine, Brigham and Women’s Hospital, Boston, MA, USA
| | - Kui Ding
- Department of Surgery, Brigham and Women’s Hospital, Boston, MA, USA
| | - Amir Imanzadeh
- Applied Imaging Science Laboratory, Department of Radiology, Brigham and Women’s Hospital, Boston, MA, USA
| | | | - Jeffrey M Karp
- Harvard Stem Cell Institute, Harvard University, Boston, MA, USA
- Harvard-MIT Division of Health Science and Technology, Department of Medicine, Brigham and Women’s Hospital, Boston, MA, USA
| | - C Keith Ozaki
- Department of Surgery, Brigham and Women’s Hospital, Boston, MA, USA
| | - Frank J Rybicki
- Applied Imaging Science Laboratory, Department of Radiology, Brigham and Women’s Hospital, Boston, MA, USA
- Ottawa Hospital Research Institute and Division of Medical Imaging, The Ottawa Hospital Department of Radiology, University of Ottawa, Ottawa, ON, Canada
| |
Collapse
|
3
|
Patanè D, Failla G, Coniglio G, Russo G, Morale W, Seminara G, Calcara G, Bisceglie P, Malfa P. Treatment of juxta-anastomotic stenoses for failing distal radiocephalic arteriovenous fistulas: Drug-coated balloons versus angioplasty. J Vasc Access 2018; 20:209-216. [DOI: 10.1177/1129729818793102] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The aim of our study is to report the results of two types (type A, type B) paclitaxel drug-coated balloon compared with standard percutaneous transluminal angioplasty in the treatment of juxta-anastomotic stenoses of mature but failing distal radiocephalic hemodialysis arteriovenous fistulas. Two groups of 26 and 44 patients treated with two different drug-coated balloon are compared with a control group of 86 treated with standard percutaneous transluminal angioplasty. A color Doppler ultrasound was performed to evaluate stenosis and for treatment planning. We assess primary patency, defined as the absence of dysfunction of the arteriovenous fistulas, patent lesion or residual stenosis < 30% and no need for further reintervention of target lesion. Primary patency and secondary patency are evaluated after 12 months with color Doppler ultrasound for the whole arteriovenous fistulas, defined as absolute (absolute primary patency, absolute secondary patency) and target lesion. Postprocedural technical and clinical success was 100%. After 12 months, absolute primary patency is 81.8% for type A, 84.1% type B, and 54.7% for standard percutaneous transluminal angioplasty; target lesion primary patency is 92% type A, 86.4% type B, and 62.8% standard percutaneous transluminal angioplasty; absolute secondary patency is 95.4% type A, 95.5% type B, and 80.7% standard percutaneous transluminal angioplasty; target lesion secondary patency is 100% type A, 97.7% type B, and 80.7% standard percutaneous transluminal angioplasty. All the patients treated with drug-coated balloon (type A + type B) have an absolute primary patency of 83.3%, a target lesion primary patency of 87.9%, an absolute secondary patency of 95.5%, and a target lesion secondary patency of 98.4%. Our study confirms that the use of drug-coated balloon, indiscriminately among different brands, improves primary patency with statistically significant difference in comparison with standard percutaneous transluminal angioplasty and decreases reintervention of target lesion in juxta-anastomotic stenoses of failing distal arteriovenous fistulas maintaining the radiocephalic fistula as long as possible.
Collapse
Affiliation(s)
- Domenico Patanè
- Department of Diagnostic and Interventional Radiology, Azienda Ospedaliera per l’Emergenza Cannizzaro, Catania, Italy
| | - Giovanni Failla
- Department of Diagnostic and Interventional Radiology, Azienda Ospedaliera per l’Emergenza Cannizzaro, Catania, Italy
| | - Giovanni Coniglio
- Department of Diagnostic and Interventional Radiology, Azienda Ospedaliera Papardo, Messina, Italy
| | - Giorgio Russo
- IBFM CNR, Cefalù 90015(PA) and UOS Fisica Sanitaria, Azienda Ospedaliera per l’Emergenza Cannizzaro, Catania, Italy
| | - Walter Morale
- Department of Nefrology e Dialisys, Azienda Ospedaliera per l’Emergenza Cannizzaro, Catania, Italy
| | - Giuseppe Seminara
- Department of Nefrology e Dialisys, Azienda Ospedaliera per l’Emergenza Cannizzaro, Catania, Italy
| | - Giacomo Calcara
- Department of Diagnostic and Interventional Radiology, Azienda Ospedaliera per l’Emergenza Cannizzaro, Catania, Italy
| | - Paola Bisceglie
- Department of Diagnostic and Interventional Radiology, Azienda Ospedaliera per l’Emergenza Cannizzaro, Catania, Italy
| | - Pierantonio Malfa
- Department of Diagnostic and Interventional Radiology, Azienda Ospedaliera per l’Emergenza Cannizzaro, Catania, Italy
| |
Collapse
|
4
|
Sanders WG, Li H, Zhuplatov I, He Y, Kim SE, Cheung AK, Agarwal J, Terry CM. Autologous fat transplants to deliver glitazone and adiponectin for vasculoprotection. J Control Release 2017; 264:237-246. [PMID: 28867378 DOI: 10.1016/j.jconrel.2017.08.036] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 08/06/2017] [Accepted: 08/29/2017] [Indexed: 10/18/2022]
Abstract
The insulin sensitizing glitazone drugs, rosiglitazone (ROS) and pioglitazone (PGZ) both have anti-proliferative and anti-inflammatory effects and induce adipose tissue (fat) to produce the vaso-protective protein adiponectin. Stenosis due to intimal hyperplasia development often occurs after placement of arteriovenous synthetic grafts used for hemodialysis. This work was performed to characterize the in vitro and in vivo effects of ROS or PGZ incorporation in fat and to determine if fat/PGZ depots could decrease vascular hyperplasia development in a porcine model of hemodialysis arteriovenous graft stenosis. Powdered ROS or PGZ (6-6000μM) was mixed with fat explants and cultured. Drug release from fat was quantified by HPLC/MS/MS, and adiponectin and monocyte chemotactic protein-1 (MCP-1) levels in culture media were measured by ELISA. The effect of conditioned media from the culture of fat with ROS or PGZ on i) platelet-derived growth factor-BB (PDGF-BB)-stimulated proliferation of human venous smooth muscle cells (SMC) was measured by a DNA-binding assay, and ii) lipopolysaccharide (LPS)-induced human monocyte release of tumor necrosis factor-alpha (TNFα) was assessed by ELISA. In a porcine model, pharmacokinetics of PGZ from fat depots transplanted perivascular to jugular vein were assessed by HPLC/MS/MS, and retention of the fat depot was monitored by MRI. A porcine model of synthetic graft placed between carotid artery and ipsilateral jugular vein was used to assess effects of PGZ/fat depots on vascular hyperplasia development. Both ROS and PGZ significantly induced the release of adiponectin and inhibited release of MCP-1 from the fat. TNF production from monocytes stimulated with LPS was inhibited 50-70% in the presence of media conditioned by fat alone or fat and either drug. The proliferation of SMC was inhibited in the presence of media conditioned by fat/ROS cultures. Fat explants placed perivascular to the external jugular vein were retained, as confirmed by MRI at one week after placement. PGZ was detected in the fat depot, in the external jugular vein wall and in adjacent tissue at clinically relevant levels, whereas levels in plasma were below detection. External jugular vein exposed to fat incorporated with PGZ had increased adiponectin expression compared to vein exposed to fat alone. However, the development of hyperplasia within the arteriovenous synthetic grafts was unchanged by treatment with fat/PGZ depots compared to no treatment.
Collapse
Affiliation(s)
- William G Sanders
- Division of Nephrology & Hypertension, Department of Internal Medicine, University of Utah, 295 Chipeta Way, Salt Lake City, UT, USA
| | - Huan Li
- Division of Nephrology & Hypertension, Department of Internal Medicine, University of Utah, 295 Chipeta Way, Salt Lake City, UT, USA
| | - Ilya Zhuplatov
- Division of Nephrology & Hypertension, Department of Internal Medicine, University of Utah, 295 Chipeta Way, Salt Lake City, UT, USA
| | - Yuxia He
- Division of Nephrology & Hypertension, Department of Internal Medicine, University of Utah, 295 Chipeta Way, Salt Lake City, UT, USA
| | - Seong-Eun Kim
- Department of Radiology and Imaging Science, Utah Center for Advanced Imaging Research, University of Utah, 729 Arapeen Dr., Salt Lake City, UT, USA
| | - Alfred K Cheung
- Division of Nephrology & Hypertension, Department of Internal Medicine, University of Utah, 295 Chipeta Way, Salt Lake City, UT, USA; Medical Service, Veterans Affairs Salt Lake City Healthcare System, 500 Foothill Dr., 151N, Salt Lake City, UT, USA
| | - Jayant Agarwal
- Division of Plastic and Reconstructive Surgery, School of Medicine, University of Utah, 30 N. 1900 E. 3B400, Salt Lake City, UT, USA
| | - Christi M Terry
- Division of Nephrology & Hypertension, Department of Internal Medicine, University of Utah, 295 Chipeta Way, Salt Lake City, UT, USA.
| |
Collapse
|
5
|
Assessment of Novel Anti-thrombotic Fusion Proteins for Inhibition of Stenosis in a Porcine Model of Arteriovenous Graft. PLoS One 2015; 10:e0137381. [PMID: 26360605 PMCID: PMC4567316 DOI: 10.1371/journal.pone.0137381] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 08/16/2015] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Hemodialysis arteriovenous synthetic grafts (AVG) provide high volumetric blood flow rates shortly after surgical placement. However, stenosis often develops at the vein-graft anastomosis contributing to thrombosis and early graft failure. Two novel fusion proteins, ANV-6L15 and TAP-ANV, inhibit the tissue factor/factor VIIa coagulation complex and the factor Xa/factor Va complex, respectively. Each inhibitor domain is fused to an annexin V domain that targets the inhibitor activity to sites of vascular injury to locally inhibit thrombosis. This study's objective was to determine if these antithrombotic proteins are safe and effective in inhibiting AVG stenosis. METHODS A bolus of either TAP-ANV or ANV-6L15 fusion protein was administered intravenously immediately prior to surgical placement of a synthetic graft between the external jugular vein and common carotid artery in a porcine model. At surgery, the vein and artery were irrigated with the anti-thrombotic fusion protein. Control animals received intravenous heparin. At 4 weeks, MRI was performed to evaluate graft patency, the pigs were then euthanized and grafts and attached vessels were explanted for histomorphometric assessment of neointimal hyperplasia at the vein-graft anastomosis. Blood was collected at surgery, immediately after surgery and at euthanasia for serum metabolic panels and coagulation chemistries. RESULTS No acute thrombosis occurred in the control group or in either experimental group. No abnormal serum chemistries, activated clotting times or PT, PTT values were observed after treatment in experimental or control animals. However, at the vein-graft anastomosis, there was no difference between the control and experimental groups in cross-sectional lumen areas, as measured on MRI, and no difference in hyperplasia areas as determined by histomorphometry. These results suggest that local irrigation of TAP-ANV or ANV-6L15 intra-operatively was as effective in inhibiting acute graft thrombosis as intravenous administration of heparin, but failed to inhibit hyperplasia development and stenosis in AVG.
Collapse
|
6
|
Drug-Eluting Balloon for the Treatment of Failing Hemodialytic Radiocephalic Arteriovenous Fistulas: Our Experience in the Treatment of Juxta-Anastomotic Stenoses. J Vasc Access 2014; 15:338-43. [DOI: 10.5301/jva.5000211] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/14/2013] [Indexed: 12/19/2022] Open
Abstract
Purpose The purpose of this article is to report our experience with drug-eluting balloons for the treatment of juxta-anastomotic stenoses of failing radiocephalic hemodialytic arteriovenous shunt and to evaluate the primary and secondary patency (PP and SP). Methods After approval by the local hospital's Ethical and Scientific Review Board, 26 consecutive patients with juxta-anastomotic stenosis of radiocephalic hemodialytic shunt were treated with angioplasty with drug-eluting balloon. The main objective was to evaluate PP defined, in accordance with the Kidney Disease Outcomes Quality Initiative recommendation, as the absence of dysfunction of the vascular access, patent lesion or residual stenosis <30% and no need for further reintervention of the target lesion (TL). PP and SP at 6, 12 and 24 months were evaluated, with echo color doppler and phlebography, for both arteriovenous fistulae, defined as absolute, and TL. Results Immediate postprocedural technical and clinical success was 100% for all the patients; we had only one technical failure in repeated treatments. At 6 months the absolute and TL PP was 96.1%; at 12 months the absolute PP was 81.8%, TL PP 90.9%, absolute SP 95.4%, TL SP 100%; at 24 months the absolute and TL PP was 57.8%; absolute and TL SP 94.7%; only one arteriovenous fistula was lost during the period. Conclusions The use of drug-eluting balloons, after standard angioplasty, improves primary patency and decreases reinterventions of TL in juxta-anastomotic stenoses of failing native dialytic arteriovenous shunts.
Collapse
|
7
|
Terry CM, Dember LM. Novel therapies for hemodialysis vascular access dysfunction: myth or reality? Clin J Am Soc Nephrol 2013; 8:2202-12. [PMID: 24235283 DOI: 10.2215/cjn.07360713] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Hemodialysis vascular access dysfunction is a major source of morbidity for patients with ESRD. Development of effective approaches to prevent and treat vascular access failure requires an understanding of the underlying mechanisms, suitable models for preclinical testing, systems for targeted delivery of interventions to maximize efficacy and minimize toxicity, and rigorous clinical trials that use appropriate outcome measures. This article reviews the substantial progress and ongoing challenges in developing novel treatments for arteriovenous vascular access failure and focuses on localized rather than systemic interventions.
Collapse
Affiliation(s)
- Christi M Terry
- Division of Nephrology and Hypertension, University of Utah, Salt Lake City, Utah, †Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | | |
Collapse
|
8
|
Long-term resveratrol treatment prevents ovariectomy-induced osteopenia in rats without hyperplastic effects on the uterus. Br J Nutr 2013; 111:836-46. [PMID: 24073920 DOI: 10.1017/s0007114513003115] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Resveratrol (Res), a polyphenol that is abundant in many medicinal plants and is a selective oestrogen receptor modulator, exhibits multiple biological activities. In the present study, we determined whether Res prevents oestrogen deficiency-induced osteopenia and whether Res administration decreases pathological changes in the endometrium and lumen of the uterus compared with oestradiol replacement therapy (ERT). A total of sixty 3-4-month-old female Wistar rats were randomly divided into a sham-operated group (Sham) and five ovariectomy (OVX) subgroups, i.e. OVX rats as a control group (OVX); OVX rats receiving oestradiol valerate (ERT, 0·8 mg/kg); and OVX rats receiving Res 20, 40 and 80 mg/kg. Daily oral administration was initiated at week 2 after OVX for 12 weeks. A dose-response difference was observed in the effects of Res on bone mineral density (BMD) and trabecular microarchitecture. Only at the highest dose, bone loss was almost equivalent to that observed in the ERT group. The dose-response effects of Res on the biochemical parameters (alkaline phosphatase, IL-6, TNF-α and transforming growth factor-β1 concentrations in the serum as well as urinary Ca and P excretion) and the expressions of receptor activator of nuclear factor κB ligand (RANKL) and the RANKL:osteoprotegerin protein ratio in the femur were also observed. Furthermore, the thickening of the endometrium and the infiltration of lymphocytes were prevented in all the three Res-treated groups compared with the ERT group. In conclusion, Res treatment not only improves BMD and trabecular microarchitecture but also does not affect the uterus and Res might be a potential remedy for the treatment of postmenopausal osteoporosis.
Collapse
|
9
|
He Y, Terry CM, Nguyen C, Berceli SA, Shiu YTE, Cheung AK. Serial analysis of lumen geometry and hemodynamics in human arteriovenous fistula for hemodialysis using magnetic resonance imaging and computational fluid dynamics. J Biomech 2012; 46:165-9. [PMID: 23122945 DOI: 10.1016/j.jbiomech.2012.09.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 08/05/2012] [Accepted: 09/03/2012] [Indexed: 10/27/2022]
Abstract
The arteriovenous fistula (AVF) is the preferred form of vascular access for maintenance hemodialysis, but it often fails to mature to become clinically usable, likely due to aberrant hemodynamic forces. A robust pipeline for serial assessment of hemodynamic parameters and subsequent lumen cross-sectional area changes has been developed and applied to a data set from contrast-free MRI of a dialysis patient's AVF collected over a period of months after AVF creation surgery. Black-blood MRI yielded images of AVF lumen geometry, while cine phase-contrast MRI provided volumetric flow rates at the in-flow and out-flow locations. Lumen geometry and flow rates were used as inputs for computational fluid dynamics (CFD) modeling to provide serial wall shear stress (WSS), WSS gradient, and oscillatory shear index (OSI) profiles. The serial AVF lumen geometries were co-registered at 1mm intervals using respective lumen centerlines, with the anastomosis as an anatomical landmark. Lumen enlargement was limited at the vein region near the anastomosis and a downstream vein valve, potentially attributed to the physical inhibition of wall expansion at those sites. This work is the first serial and detail study of lumen and hemodynamic changes in human AVF using MRI and CFD. This novel protocol will be used for a multicenter prospective study to identify critical hemodynamic factors that contribute to AVF maturation failure.
Collapse
Affiliation(s)
- Yong He
- Department of Surgery, University of Florida, Gainesville, FL, USA
| | | | | | | | | | | |
Collapse
|
10
|
Sanders WG, Morisseau C, Hammock BD, Cheung AK, Terry CM. Soluble epoxide hydrolase expression in a porcine model of arteriovenous graft stenosis and anti-inflammatory effects of a soluble epoxide hydrolase inhibitor. Am J Physiol Cell Physiol 2012; 303:C278-90. [PMID: 22621785 PMCID: PMC3423029 DOI: 10.1152/ajpcell.00386.2011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 05/21/2012] [Indexed: 01/09/2023]
Abstract
Synthetic arteriovenous (AV) grafts, placed between an artery and vein, are used for hemodialysis but often fail due to stenosis, typically at the vein-graft anastomosis. This study recorded T lymphocyte and macrophage accumulation at the vein-graft anastomosis, suggesting a role for inflammation in stenosis development. Epoxyeicosatrienoic acids (EETs), products of cytochrome P-450 epoxidation of arachidonic acid, have vasculoprotective and anti-inflammatory effects including inhibition of platelet activation, cell migration, and adhesion. EETs are hydrolyzed by soluble epoxide hydrolase (sEH) to less active diols. The effects of a specific inhibitor of sEH (sEHI) on cytokine release from human monocytes and mouse bone marrow-derived macrophages (BMMΦ) from wild-type (WT) and sEH knockout (KO) animals were investigated. Expression of sEH protein increased over time at the anastomosis as evaluated by immunohistochemistry. Pre-exposure of adherent human monocytes to sEHI (5 μM) significantly inhibited lipopolysaccharide-induced release of monocyte chemotactic protein-1 (MCP-1) and tumor necrosis factor-α and enhanced the EET-to-diol ratio. Release of MCP-1 from WT BMMΦ was significantly inhibited but release from sEH KO BMMΦ was not attenuated indicating the specificity of the sEHI. In contrast, sEHI did not inhibit the release of macrophage inflammatory protein-1 or interleukin-6. Nuclear translocation of NF-κB, as assessed by immunocytochemical staining, was not decreased with sEHI in monocytes, but the phosphorylation of JNK was completely abrogated, suggesting this pathway is the target of sEHI effects in monocytes. These results suggest that sEHI may be useful for inhibition of inflammation and subsequently stenosis in AV grafts.
Collapse
Affiliation(s)
- William G Sanders
- Department of Pharmaceutics, University of Utah, Salt Lake City, Utah 84112, USA
| | | | | | | | | |
Collapse
|
11
|
Sanders WG, Hogrebe PC, Grainger DW, Cheung AK, Terry CM. A biodegradable perivascular wrap for controlled, local and directed drug delivery. J Control Release 2012; 161:81-9. [PMID: 22561340 PMCID: PMC3378780 DOI: 10.1016/j.jconrel.2012.04.029] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 04/16/2012] [Indexed: 01/25/2023]
Abstract
Perivascular delivery of anti-proliferative agents is an attractive approach to inhibit hyperplasia that causes stenosis of synthetic hemodialysis grafts and other vascular grafts. Perivascular drug delivery systems typically release drugs to both the vascular wall and non-target extravascular tissue. The objective of this study was to develop a biodegradable, perivascular delivery system for localized, sustained and unidirectional drug release in the context of synthetic arteriovenous (AV) grafts used for chronic hemodialysis. To this end, a dense non-porous polymer barrier layer was laminated to either i) a drug-loaded non-porous polymer layer or ii) a porous polymer layer. To provide tunability, the porous layer could be loaded with drug during casting or later infused with a drug-loaded hydrogel. The polymer bilayer wraps were prepared by a solvent casting, thermal-phase inversion technique using either polylactide-co-glycolide (PLGA) or polycaprolactone (PCL). Sunitinib, a multi-target receptor tyrosine kinase inhibitor, was used as a model drug. In a modified transwell chamber system, the barrier function of the non-porous PLGA backing was superior to the non-porous PCL backing although both markedly inhibited drug diffusion. As assessed by in vitro release assays, drug release duration from the drug-loaded non-porous PCL construct was almost 4-fold greater than release from the porous PCL construct infused with drug-laden hydrogel (22 days vs. 5 days); release duration from the drug-loaded non-porous PLGA construct was prolonged approximately 3-fold over release from the porous PLGA construct infused with drug-laden hydrogel (9 days vs. 3 days). Complete in vitro degradation of the PLGA porous and non-porous constructs occurred by approximately 35 days whereas the PCL constructs remained intact even after most of the drug was released (49 days). The PLGA non-porous bilayer wrap containing 143±5.5mg sunitinib in the inner layer was chosen for further pharmacokinetic assessment in vivo where the construct was placed around the external jugular vein in a porcine model. At 1 week, no drug was detected by HPLC/MS/MS in any examined extravascular tissue whereas high levels of drug were detected in the wrapped vein segment (1048 ng g⁻¹ tissue). At 4 weeks, drug was detected in adjacent muscle (52 ng g⁻¹ tissue) but 13-fold greater amounts were detected in the wrapped vein segment (1742 ng g⁻¹ tissue). These results indicate that the barrier layer effectively impedes extravascular drug loss. Tensile testing showed that the initially flexible PLGA construct stiffened with hydration, a phenomenon also observed after in vivo placement. This characteristic may be useful to resist undue circumferential venous tensile stress produced in AV grafting. The PLGA wrap bilayer formulation is a promising perivascular drug delivery design for local treatment of hemodialysis AV graft hyperplasia and possibly other hyperplastic vascular disorders.
Collapse
Affiliation(s)
- William G Sanders
- Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, UT 84112, USA.
| | | | | | | | | |
Collapse
|
12
|
Terry CM, Li L, Li H, Zhuplatov I, Blumenthal DK, Kim SE, Owen SC, Kholmovski EG, Fowers KD, Rathi R, Cheung AK. In vivo evaluation of the delivery and efficacy of a sirolimus-laden polymer gel for inhibition of hyperplasia in a porcine model of arteriovenous hemodialysis graft stenosis. J Control Release 2012; 160:459-67. [PMID: 22465391 DOI: 10.1016/j.jconrel.2012.03.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 03/07/2012] [Accepted: 03/11/2012] [Indexed: 12/22/2022]
Abstract
Synthetic arteriovenous (AV) hemodialysis grafts are plagued by hyperplasia resulting in occlusion and graft failure yet there are no clinically available preventative treatments. Here the delivery and degradation of a sirolimus-laden polymer gel were monitored in vivo by magnetic resonance imaging (MRI) and its efficacy for inhibiting hyperplasia was evaluated in a porcine model of AV graft stenosis. Synthetic grafts were placed between the carotid artery and ipsilateral jugular vein of swine. A biodegradable polymer gel loaded with sirolimus (2.5mg/mL) was immediately applied perivascularly to the venous anastomosis, and reapplied by ultrasound-guided injections at one, two and three weeks. Control grafts received neither sirolimus nor polymer. The lumen cross-sectional area at the graft-vein anastomosis was assessed in vivo by non-invasive MRI. The explanted tissues also underwent histological analysis. A specifically developed MRI pulse sequence provided a high contrast-to-noise ratio (CNR) between the polymer and surrounding tissue that allowed confirmation of gel location after injection. Polymer signal decreased up to 80% at three to four weeks after injection, slightly faster than its degradation kinetics in vitro. The MR image of the polymer was confirmed by visual assessment at necropsy. On histological assessment, the mean hyperplasia surface area of the treated graft was 52% lower than that of the control grafts (0.43mm(2) vs. 0.89mm(2); p<0.003), while the minimum cross-sectional lumen area, as measured on MRI, was doubled (5.3mm(2) vs 2.5mm(2); p<0.05). In conclusion, customized MRI allowed non-invasive monitoring of the location and degradation of drug delivery polymer gels in vivo. Perivascular application of sirolimus-laden polymer yielded a significant decrease in hyperplasia development and an increase in lumen area at the venous anastomosis of AV grafts.
Collapse
Affiliation(s)
- Christi M Terry
- Division of Nephrology and Hypertension, University of Utah, 85 N. Medical Dr. East, Salt Lake City, UT 84112, United States.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Lee T, Chauhan V, Krishnamoorthy M, Wang Y, Arend L, Mistry MJ, El-Khatib M, Banerjee R, Munda R, Roy-Chaudhury P. Severe venous neointimal hyperplasia prior to dialysis access surgery. Nephrol Dial Transplant 2011; 26:2264-70. [PMID: 21220751 DOI: 10.1093/ndt/gfq733] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Venous neointimal hyperplasia is the most common cause of arteriovenous (AV) fistula and graft dysfunction following dialysis access surgery. However, the pathogenetic impact of pre-existing venous neointimal hyperplasia at the time of AV access creation on final clinical success is currently unknown in the setting of advanced chronic kidney disease (CKD) and end-stage renal disease (ESRD) patients. The aim of this study was to perform a detailed histological, morphometric, and immunohistochemical analysis of vein specimens in advanced CKD and ESRD patients collected at the time of new vascular access placement. METHODS Vein samples from 12 patients were collected at the time of AV access creation near the site of AV anastomosis. Histological, immunohistochemistry and morphometric studies were performed on these vein samples. RESULTS Examination of the tissue specimens obtained at the time of surgery showed neointimal hyperplasia in 10 of 12 specimens, ranging from minimal to very severe. The majority of cells within the neointima were myofibroblasts with a minority of contractile smooth muscle cells present. CONCLUSION Our work represents a detailed description of the morphometric and cellular phenotypic lesions present in the veins of CKD and ESRD patients, prior to dialysis access placement. These studies (i) suggest the future possibility of a new predictive marker (pre-existing venous neointimal hyperplasia) for AV dialysis access dysfunction and (ii) open the door for the future development of novel local therapies for optimization of the venous substrate on which the dialysis access is created.
Collapse
Affiliation(s)
- Timmy Lee
- Department of Clinical and Experimental Medicine, Federico II University Medical School, Naples, Italy.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Mitsouras D, Vemula PK, Yu P, Tao M, Nguyen BT, Campagna CM, Karp JM, Mulkern RV, Ozaki CK, Rybicki FJ. Immobilized contrast-enhanced MRI: Gadolinium-based long-term MR contrast enhancement of the vein graft vessel wall. Magn Reson Med 2010; 65:176-83. [PMID: 20859994 DOI: 10.1002/mrm.22606] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
An implantable MR contrast agent that can be covalently immobilized on tissue during surgery has been developed. The rationale is that a durable increase in tissue contrast using an implantable contrast agent can enhance postsurgical tissue differentiation using MRI. For small-vessel (e.g., vein graft) MRI, the direct benefit of such permanent "labeling" of the vessel wall by modification of its relaxation properties is to achieve more efficient imaging. This efficiency can be realized as either increased contrast leading to more accurate delineation of vessel wall and lesion tissue boundaries, or, faster imaging without penalizing contrast-to-noise ratio, or a combination thereof. We demonstrate, for the first time, stable long-term MRI enhancement using such an exogenous contrast mechanism based on immobilizing a modified diethylenetriaminepentaacetic acid gadolinium(3+) dihydrogen complex on a human vein using a covalent amide bond. Signal enhancement due to the covalently immobilized contrast agent is demonstrated for excised human vein specimens imaged at 3 T, and its long-term stability is demonstrated during a 4-month incubation period.
Collapse
Affiliation(s)
- Dimitris Mitsouras
- Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Rybicki FJ, Mitsouras D, Owens CD, Whitmore A, Gerhard-Herman M, Wake N, Cai T, Zhou Q, Conte MS, Creager MA, Mulkern RV. Multi-contrast high spatial resolution black blood inner volume three-dimensional fast spin echo MR imaging in peripheral vein bypass grafts. Int J Cardiovasc Imaging 2010; 26:683-91. [PMID: 20333469 DOI: 10.1007/s10554-010-9621-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2010] [Accepted: 03/09/2010] [Indexed: 01/20/2023]
Abstract
The purpose of this study is to primarily evaluate the lumen area and secondarily evaluate wall area measurements of in vivo lower extremity peripheral vein bypass grafts patients using high spatial resolution, limited field of view, cardiac gated, black blood inner volume three-dimensional fast spin echo MRI. Fifteen LE-PVBG patients prospectively underwent ultrasound followed by T1-weighted and T2-weighted magnetic resonance (MR) imaging. Lumen and vessel wall areas were measured by direct planimetry. For graft lumen areas, T1- and T2-weighted measurements were compared with ultrasound. For vessel wall areas, differences between T1- and T2-weighted measurements were evaluated. There was no significant difference between ultrasound and MR lumen measurements, reflecting minimal MR blood suppression artifact. Graft wall area measured from T1-weighted images was significantly larger than that measured from T2-weighted images (P < 0.001). The mean of the ratio of T1- versus T2-weighted vessel wall areas was 1.59 (95% CI: 1.48-1.69). The larger wall area measured on T1-weighted images was due to a significantly larger outer vessel wall boundary. Very high spatial resolution LE-PVBG vessel wall MR imaging can be performed in vivo, enabling accurate measurements of lumen and vessel wall areas and discerning differences in those measures between different tissue contrast weightings. Vessel wall area differences suggest that LE-PVBG vessel wall tissues produce distinct signal characteristics under T1 and T2 MR contrast weightings.
Collapse
Affiliation(s)
- Frank J Rybicki
- Applied Imaging Science Laboratory, Department of Radiology, Brigham and Women's Hospital, Boston, MA, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|