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Peng T Khaw - One of the best experts on this subject based on the ideXlab platform.
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lc ms analysis to determine the biodistribution of a polymer coated Ilomastat ocular implant
Journal of Pharmaceutical and Biomedical Analysis, 2018Co-Authors: Abeer H A Mohamedahmed, Alastair Lockwood, Peng T Khaw, Steve Brocchini, Hala M Fadda, Shivam Madaan, Kersti KaruAbstract:Abstract Ilomastat is a matrix metalloproteinase inhibitor (MMPi) that has shown the potential to inhibit scarring (fibrosis) by mediating healing after injury or surgery. A long lasting ocular implantable pharmaceutical formulation of Ilomastat is being developed to mediate the healing process to prevent scarring after glaucoma filtration surgery. The Ilomastat implant was coated with water permeable and biocompatible phosphoryl choline polymer (PC1059) displayed extended slow release of Ilomastat in vitro and in vivo. The ocular distribution of Ilomastat from the implant in rabbits at day 30 post surgery was determined by the extraction of Ilomastat and its internal standard marimastat from the ocular tissues, plasma, aqueous humour and vitreous fluid followed by capillary-flow liquid chromatography (cap-LC), the column effluent was directed into a triple quadrupole mass spectrometer operating in product scan mode. The lower limits of quantification (LLOQs) were 0.3 pg/μL for ocular fluids and plasma, and 3 pg/mg for ocular tissues. The extraction recoveries were 90–95% for Ilomastat and its internal standard from ocular tissues. Ilomastat was found in ocular fluids and tissues at day 30 after surgery. The level of Ilomastat was 18 times higher in the aqueous humour than vitreous humour. The concentration ranking of Ilomastat in the ocular tissues was sclera > bleb conjunctiva > conjunctiva (rest of the eye) > cornea. Mass spectrometry analysis to confirm the presence of Ilomastat in the ocular tissues and fluids at day 30 post-surgery establishes the extended release of Ilomastat can be achieved in vivo, which is crucial information for optimisation of the Ilomastat coated implant.
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an Ilomastat cd eye drop formulation to treat ocular scarring
Investigative Ophthalmology & Visual Science, 2017Co-Authors: Abeer H A Mohamedahmed, Alastair Lockwood, He Li, Maryse Bailly, Peng T Khaw, Steve BrocchiniAbstract:PURPOSE: The purpose of this study was to develop a topical matrix metalloproteinase inhibitor preparation for antiscarring therapy. METHODS: The broad spectrum matrix metalloproteinase inhibitor Ilomastat was formulated using 2-hydroxypropyl-β-cyclodextrin in aqueous solution. In vitro activity of Ilomastat-cyclodextrin (Ilomastat-CD) was examined using fibroblasts seeded in collagen. Permeation of Ilomastat-CD eye drop through pig eye conjunctiva was confirmed using Franz diffusion cells. Ilomastat-CD eye drop was applied to rabbit eyes in vivo, and the distribution of Ilomastat in ocular tissues and fluids was determined by liquid chromatography-mass spectroscopy. RESULTS: The aqueous solubility of Ilomastat-CD was ∼1000 μg/mL in water and 1400 μg/mL in PBS (pH 7.4), which is greater than Ilomastat alone (140 and 160 μg/mL in water and PBS, respectively). The in vitro activity of Ilomastat-CD to inhibit collagen contraction in the presence of human Tenon fibroblast cells was unchanged compared to uncomplexed Ilomastat. Topically administered Ilomastat-CD in vivo to rabbit eyes resulted in a therapeutic concentration of Ilomastat being present in the sclera and conjunctiva and within the aqueous humor. CONCLUSIONS: Ilomastat-CD has the potential to be formulated as an eye drop for use as an antifibrotic, which may have implications for the prevention of scarring in many settings, for example glaucoma filtration surgery.
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Molecular dynamic simulations of ocular tablet dissolution
Journal of Chemical Information and Modeling, 2013Co-Authors: Qian Ru, Peng T Khaw, Steve Brocchini, Hala M Fadda, Chung Li, Daniel Paul, Mire ZlohAbstract:Small tablets for implantation into the subconjunctival space in the eye are being developed to inhibit scarring after glaucoma filtration surgery (GFS). There is a need to evaluate drug dissolution at the molecular level to determine how the chemical structure of the active may correlate with dissolution in the nonsink conditions of the conjunctival space. We conducted molecular dynamics simulations to study the dissolution process of tablets derived from two drugs that can inhibit fibrosis after GFS, 5-fluorouracil (5-FU) and the matrix metalloprotease inhibitor (MMPi), Ilomastat. The dissolution was simulated in the presence of simple point charge (SPC) water molecules, and the liquid turnover of the aqueous humor in the subconjunctival space was simulated by removal of the dissolved drug molecules at regular intervals and replacement by new water molecules. At the end of the simulation, the total molecular solvent accessible surface area of 5-FU tablets increased by 60 times more than that of ilomasta...
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Characterisation of Ilomastat for Prolonged Ocular Drug Release
AAPS PharmSciTech, 2012Co-Authors: Gary Parkinson, Alastair Lockwood, Peng T Khaw, Steve Brocchini, Qian Ru, Simon Gaisford, Ashkan Khalili, Rose Sheridan, Hala M FaddaAbstract:We are developing tablet dosage forms for implantation directly into the subconjunctival space of the eye. The matrix metalloproteinase inhibitor, Ilomastat, has previously been shown to be efficacious at suppressing scarring following glaucoma filtration surgery (GFS). We report on the physical characterisation of Ilomastat which is being developed for ocular implantation. Since Ilomastat is being considered for implantation it is necessary to examine its polymorphs and their influence on aspects of the in vitro drug release profile. X-ray powder diffraction identified two polymorphs of Ilomastat from different commercial batches of the compound. Tablets were prepared from the two different polymorphs. Isothermal perfusion calorimetry was used to show that amorphous content is not increased during tablet formulation. The melting points of the two polymorphs are 188 and 208°C as determined by differential scanning calorimetry. Utilising single crystal X-ray diffraction, the structural conformations and packing arrangements of the different polymorphs were determined. The orthorhombic crystal crystallised as a monohydrate while the second monoclinic crystal form is non-solvated. Ilomastat tablets prepared from the two different solid forms exhibited similar drug release profiles in vitro under conditions mimicking the aqueous composition, volume and flow of the subconjunctival space after GFS. This suggests that a reproducible dose at each time point during release after implantation should be achievable in vivo with Ilomastat tablets prepared from the two polymorphs identified.
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Matrix Metalloproteinase Inhibition Reduces Contraction by Dupuytren Fibroblasts
Journal of Hand Surgery (European Volume), 2008Co-Authors: W.a. Townley, Peng T Khaw, Alison D. Cambrey, Adriaan O. GrobbelaarAbstract:Purpose Dupuytren's disease is a common fibroproliferative condition of the hand characterized by fibrotic lesions (nodules and cords), leading to disability through progressive digital contracture. Although the etiology of the disease is poorly understood, recent evidence suggests that abnormal matrix metalloproteinase (MMP) activity may play a role in cell-mediated collagen contraction and tissue scarring. The aim of this study was to investigate the efficacy of Ilomastat, a broad-spectrum MMP inhibitor, in an in vitro model of Dupuytren fibroblast–mediated contraction. Methods Nodule-derived and cord-derived fibroblasts were isolated from Dupuytren patients; carpal ligament–derived fibroblasts acted as control. Stress-release fibroblast-populated collagen lattices (FPCLs) were used as a model of contraction. FPCLs were allowed to develop mechanical stress (48 hours) during treatment with Ilomastat (0–100 μmol/L), released, and allowed to contract over a 48-hour period. Contraction was estimated by measuring lattice area compared with untreated cells or treatment with a control peptide. MMP-1, MMP-2, and MT1-MMP levels were assessed by zymography, Western blotting, and enzyme-linked immunosorbent assay. Results Nodule-derived fibroblasts contracted lattices (69% ± 2) to a greater extent than did cord-derived (55% ± 3) or carpal ligament–derived (55% ± 1) fibroblasts. Exposure to Ilomastat led to significant inhibition of lattice contraction by all fibroblasts, although a reduction in lattice contraction by nodule-derived fibroblasts was most prominent (84% ± 8). In addition, treatment with Ilomastat led to a concomitant suppression of MMP-1 and MMP-2 activity, whereas MT1-MMP activity was found to be upregulated. Conclusions Our results demonstrate that inhibition of MMP activity results in a reduction in extracellular matrix contraction by Dupuytren fibroblasts and suggest that MMP activity may be a critical target in preventing recurrent contracture caused by this disease.
Derek M. Yellon - One of the best experts on this subject based on the ideXlab platform.
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246 characterisation of Ilomastat mediated protection
Heart, 2013Co-Authors: Robert M. Bell, K Phua, Derek M. YellonAbstract:We have recently demonstrated that broad-spectrum matrix metalloproteinase (MMP) inhibition with Ilomastat significantly attenuates infarct size when administered upon reperfusion following injurious ischaemia. Unlike pre- or post-conditioning that are thought to be reliant upon inhibition of mitochondrial permeability transition pore (mPTP), Ilomastat protection occurs even in the absence of the critical mPTP regulatory protein, cyclophilin-D. MMP-inhibited cardioprotection remains incompletely characterised; we hypothesised that conditioning plus MMP inhibition would lead to summative infarct attenuation. In 5–6 week old C57Bl6, Langendorff-perfused mouse hearts, Ilomastat (250 nmol/L) was administered for 15 min after 35 min of global ischaemia prior to assessment of infarct size by triphenyl tetrazolium chloride staining. As found previously, Ilomastat administered from the onset of reperfusion significantly attenuated infarct size (from 34±2.2% to 21±3.5% p To study the efficacy of Ilomastat protection, we undertook a dose-response curve of increasing durations of injurious ischaemia in 10min intervals from 30 to 60 min. Interestingly, while iPost became ineffective against 50 min of injurious ischaemia, Ilomastat remained protective (48±5.6%, 44±3.6% and 32±2.4% respectively, p Curiously, neither pre- nor postconditioning were able to augment the protection seen with Ilomastat after 35min ischaemia. Pharmacologically targeting cyclophilin-D at reperfusion with cyclosporine A (CsA, 200 nmol/L) resulted in significant attenuation of infarct size when compared to control (24±5% versus 34±2.2%, p Ilomastat offers robust protection against injurious ischaemia/reperfusion injury when administered during the first minutes of reperfusion and has greater efficacy than iPost against longer ischaemic insults. However, the robust summative protection seen previously with Ilomastat in cyclophilin-D knockout mice does not translate to additive protection with either ischaemic pre- or post-conditioning, or with pharmacological inhibition of cyclophilin using CsA. Therefore MMP inhibition still offers a novel approach to infarct size reduction, but there appears no benefit in combining this therapy with other cardioprotective modalities.
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Matrix metalloproteinase inhibition protects CyPD knockout mice independently of RISK/mPTP signalling: a parallel pathway to protection.
Basic Research in Cardiology, 2013Co-Authors: Robert M. Bell, Cara Hendry, D Bruce-hickman, Sean M. Davidson, Suma P. Kunuthur, Derek M. YellonAbstract:The mitochondrial permeability transition pore (mPTP) is widely accepted as an end-effector mechanism of conditioning protection against injurious ischaemia/reperfusion. However, death can be initiated in cells without pre-requisite mPTP opening, implicating alternate targets for ischaemia/reperfusion injury amelioration. Matrix metalloproteinases (MMP) are known to activate extrinsic apoptotic cascades and therefore we hypothesised that MMP activity represents an mPTP-independent target for augmented attenuation of ischaemia/reperfusion injury. In ex vivo and in vivo mouse hearts, we investigated whether the MMP inhibitor, Ilomastat (0.25 μmol/l), administered upon reperfusion could engender protection in the absence of cyclophilin-D (CyPD), a modulator of mPTP opening, against injurious ischaemia/reperfusion. Ilomastat attenuated infarct size in wild-type (WT) animals [37 ± 2.8 to 22 ± 4.3 %, equivalent to ischaemic postconditioning (iPostC), used as positive control, 27 ± 2.1 %, p < 0.05]. Control CyPD knockout (KO) hearts had smaller infarcts than control WT (28 ± 4.2 %) and iPostC failed to confer additional protection, yet Ilomastat significantly attenuated infarct size in KO hearts (11 ± 3.0 %, p < 0.001), and similar protection was also seen in isolated cardiomyocytes. Moreover, Ilomastat, unlike the cyclophilin inhibitor cyclosporine-A, had no impact upon reactive oxygen species-mediated mPTP opening. While MMP inhibition was associated with increased Akt and ERK phosphorylation, neither Wortmannin nor PD98059 abrogated Ilomastat-mediated protection. We demonstrate that MMP inhibition is cardioprotective, independent of Akt/ERK/CyPD/mPTP activity and is additive to the protection observed following inhibition of mPTP opening, indicative of a parallel pathway to protection in ischaemic/reperfused heart that may have clinical applicability in attenuating injury in acute coronary syndromes and deserve further investigation.
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Matrix metalloproteinase inhibition protects CyPD knockout mice independently of RISK/mPTP signalling: a parallel pathway to protection
Basic Research in Cardiology, 2013Co-Authors: Robert M. Bell, Cara Hendry, D Bruce-hickman, Suma P. Kunuthur, Sean Davidson, Derek M. YellonAbstract:The mitochondrial permeability transition pore (mPTP) is widely accepted as an end-effector mechanism of conditioning protection against injurious ischaemia/reperfusion. However, death can be initiated in cells without pre-requisite mPTP opening, implicating alternate targets for ischaemia/reperfusion injury amelioration. Matrix metalloproteinases (MMP) are known to activate extrinsic apoptotic cascades and therefore we hypothesised that MMP activity represents an mPTP-independent target for augmented attenuation of ischaemia/reperfusion injury. In ex vivo and in vivo mouse hearts, we investigated whether the MMP inhibitor, Ilomastat (0.25 μmol/l), administered upon reperfusion could engender protection in the absence of cyclophilin-D (CyPD), a modulator of mPTP opening, against injurious ischaemia/reperfusion. Ilomastat attenuated infarct size in wild-type (WT) animals [37 ± 2.8 to 22 ± 4.3 %, equivalent to ischaemic postconditioning (iPostC), used as positive control, 27 ± 2.1 %, p
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116 Matrix metalloproteinase inhibition attenuates reperfusion injury, independently of and additive to mitochondrial permeability transition pore inhibition
Heart, 2012Co-Authors: Robert M. Bell, D Bruce-hickman, Sean M. Davidson, R Breckenridge, Cara Hendy, Derek M. YellonAbstract:While matrix-metalloproteinase (MMP) inhibitors appear to protect against myocardial ischaemia/reperfusion injury, the mechanisms are poorly understood. We hypothesised that cardioprotection resultant from MMP inhibition is independent of mitochondrial permeability transition pore (mPTP), the end-effector of ischaemic postconditioning (iPOC). In ex-vivo and in-vivo mouse hearts, we investigated whether the MMP inhibitor, ilomostat (0.25 μmol/l), at the onset of reperfusion, could engender protection in the absence of cyclophillin-D (CyPD), an initiator of mPTP opening, against injurious ischaemia/reperfusion. We have previously demonstrated that CyPD knockout (KO) hearts have inherent resistance to ischaemia/reperfusion injury, and cannot be further protected by either pre or post conditioning regimen. Therefore to further attenuate infarction in this model would require a mechanism independent of the mPTP. We found that Ilomastat attenuated infarct size in wild type (WT) animals (37%±2.8% to 22%±4.3%, equivalent to ischaemic post conditioning (iPostC—6 cycles of 10sec reperfusion/ischaemia), 27%±2.1%, p
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16 Matrix metalloproteinase inhibition is a parallel pathway to protection against reperfusion injury, both independent and additive to mitochondrial permeability transition pore inhibition
Heart, 2011Co-Authors: Robert M. Bell, Cara Hendry, D Bruce-hickman, Sean M. Davidson, R Breckenridge, Derek M. YellonAbstract:While matrix-metalloproteinase (MMP) inhibition protects against myocardial ischaemia/reperfusion injury, the mechanisms are poorly understood. We hypothesised that this cardioprotection is independent of mitochondrial permeability transition pore (mPTP) inhibition, the end-effector of ischaemic postconditioning (iPOC). In ex vivo and in vivo mouse hearts, we investigated whether the MMP inhibitor, ilomostat (0.25 μmol/l), at reperfusion, could engender protection in the absence of cyclophillin-D (CyPD), an initiator of mPTP opening, against injurious ischaemia/reperfusion. Ilomastat attenuated infarct size in wild type (WT) animals (37±2.8 to 22±4.3%, equivalent to iPOC, 27±2.1%, p
Mark B Sherwood - One of the best experts on this subject based on the ideXlab platform.
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A sequential, multiple-treatment, targeted approach to reduce wound healing and failure of glaucoma filtration surgery in a rabbit model (an American Ophthalmological Society thesis).
Transactions of the American Ophthalmological Society, 2020Co-Authors: Mark B SherwoodAbstract:PURPOSE: The purpose of this study was to evaluate the concept of targeting mediators of the scarring process at multiple points across the course of bleb failure, in order to prolong bleb survival. METHODS: There were three linked parts to the experiment. In the first part, a cannula glaucoma filtration surgery (GFS) was performed on 32 New Zealand White (NZW) rabbits, and bleb survival was assessed for six different regimens plus controls by grading bleb height and width. For the second part of the study, the same GFS surgery was performed on an additional 10 NZW rabbits. Two additional filtering blebs were treated with balanced saline solution (BSS), two received mitomycin-C (MMC) (0.4 mg/mL), and for the remaining six, a sequential regimen was given consisting of 200 mmol/L mannose-6-phosphate (M-6-P) solution at the time of surgery, followed by subconjunctival injections of antibody to connective tissue growth factor at days 2 and 4, and Ilomastat, a broad-spectrum matrix metalloproteinase inhibitor, at days 7, 12, and 20 postoperatively. Bleb survival was again assessed. In the final part of the experiment, blebs treated with either BSS, MMC, or the above sequential multitreatment regimen were examined histologically at 14 days postoperatively in three additional NZW rabbits. RESULTS: All six individual therapies selected resulted in some improvement of bleb survival compared to BSS control. Blebs treated with the new sequential, multitreatment protocol survived an average of 29 days (regression slope, P < .0001 compared to control), those receiving BSS an average of 17 days, and those treated with MMC (0.4 mg/mL) an average of 36 days. The sequential, multitreatment regimen was significantly superior to any of the six monotherapies for time to zero analysis (flattening) of the bleb (P < .002). Histologic examination of the bleb tissues showed a markedly less epithelial thinning, subepithelial collagen thinning, and goblet cell loss in the multitreatment group, when compared with the MMC blebs. CONCLUSIONS: In a rabbit model of GFS, a sequential, targeted, multitreatment approach prolonged bleb survival compared to BSS controls and decreased bleb tissue morphological changes when compared to those treated with MMC. It is not known whether these findings can be reproduced in humans, and further work is needed to determine an optimum regimen and timing of therapeutic delivery.
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sequential therapy with saratin bevacizumab and Ilomastat to prolong bleb function following glaucoma filtration surgery in a rabbit model
PLOS ONE, 2015Co-Authors: Gina M Martorana, Jamie L Schaefer, Monica A Levine, Zachary Lee Lukowski, Craig Meyers, Gregory S Schultz, Mark B SherwoodAbstract:To determine if sequential treatment with Bevacizumab (Avastin), a monoclonal, VEGF antibody that blocks angiogenesis; Saratin, a 12 kD polypeptide with anti-inflammatory and anti-thrombotic properties; and Ilomastat, a matrix metalloproteinase (MMP) inhibitor, prolongs bleb life following glaucoma filtration surgery (GFS) in a rabbit model. Thirty-two New Zealand White rabbits (eight rabbits per group) underwent GFS in the left eye. Group 1 received a perioperative injection of both Saratin and Bevacizumab, and later, subconjuctival injections of Ilomastat on days 8 and 15. Group 2 received only Saratin perioperatively, and also received Ilomastat injections on days 8 and 15. Group 3, the negative control, received a single perioperative injection of Balanced Saline Solution (BSS) along with post-operative BSS injections on days 8 and 15. Group 4, the positive control, received topical treatment with Mitomycin-C (MMC) at the time of surgery with no further treatment. Blebs were evaluated by an observer masked to treatment every third day. Histology was obtained on two eyes in each group on post-op day twelve as well as all eyes following bleb failure. Eyes in group 1 had a mean bleb survival time of 29 ± 2.7 days, whereas those in group 2 that received the experimental treatment without Bevacizumab had a mean survival time of 25.5 ± 2.7 days. An ANOVA test showed that the Saratin/Ilomastat/Bevacizumab group demonstrated a significant prolongation of bleb survival compared to the BSS control—mean survival time of 19.7 ±2.7 days—(p = 0.0252) and was not significantly different from the MMC positive control group (p = 0.4238)—mean survival time of 32.5 ± 3.3. From tissue histology at day 12, the four different groups showed marked differences in the cellularity and capsule fibrosis. The MMC eyes showed minimal cellularity, were avascular and had minimal fibrous tissue. BSS group showed high cellularity, moderate to high fibrosis, and thicker and more defined capsules than either of the treatment groups and the positive control. Both the Saratin/Ilomastat/Bevacizumab and Saratin/Ilomastat only eyes showed moderate cellularity with minimal fibrosis, with less cellularity and fibrosis present in the triple treatment group. Sequential therapy with multiple agents, including Bevacizumab, prolonged bleb function following GFS in the rabbit model and were significantly better than the negative BSS control. The experimental group did not show the same surface tissue histological thinning and side effects associated with MMC treatment.
Robert M. Bell - One of the best experts on this subject based on the ideXlab platform.
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246 characterisation of Ilomastat mediated protection
Heart, 2013Co-Authors: Robert M. Bell, K Phua, Derek M. YellonAbstract:We have recently demonstrated that broad-spectrum matrix metalloproteinase (MMP) inhibition with Ilomastat significantly attenuates infarct size when administered upon reperfusion following injurious ischaemia. Unlike pre- or post-conditioning that are thought to be reliant upon inhibition of mitochondrial permeability transition pore (mPTP), Ilomastat protection occurs even in the absence of the critical mPTP regulatory protein, cyclophilin-D. MMP-inhibited cardioprotection remains incompletely characterised; we hypothesised that conditioning plus MMP inhibition would lead to summative infarct attenuation. In 5–6 week old C57Bl6, Langendorff-perfused mouse hearts, Ilomastat (250 nmol/L) was administered for 15 min after 35 min of global ischaemia prior to assessment of infarct size by triphenyl tetrazolium chloride staining. As found previously, Ilomastat administered from the onset of reperfusion significantly attenuated infarct size (from 34±2.2% to 21±3.5% p To study the efficacy of Ilomastat protection, we undertook a dose-response curve of increasing durations of injurious ischaemia in 10min intervals from 30 to 60 min. Interestingly, while iPost became ineffective against 50 min of injurious ischaemia, Ilomastat remained protective (48±5.6%, 44±3.6% and 32±2.4% respectively, p Curiously, neither pre- nor postconditioning were able to augment the protection seen with Ilomastat after 35min ischaemia. Pharmacologically targeting cyclophilin-D at reperfusion with cyclosporine A (CsA, 200 nmol/L) resulted in significant attenuation of infarct size when compared to control (24±5% versus 34±2.2%, p Ilomastat offers robust protection against injurious ischaemia/reperfusion injury when administered during the first minutes of reperfusion and has greater efficacy than iPost against longer ischaemic insults. However, the robust summative protection seen previously with Ilomastat in cyclophilin-D knockout mice does not translate to additive protection with either ischaemic pre- or post-conditioning, or with pharmacological inhibition of cyclophilin using CsA. Therefore MMP inhibition still offers a novel approach to infarct size reduction, but there appears no benefit in combining this therapy with other cardioprotective modalities.
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Matrix metalloproteinase inhibition protects CyPD knockout mice independently of RISK/mPTP signalling: a parallel pathway to protection.
Basic Research in Cardiology, 2013Co-Authors: Robert M. Bell, Cara Hendry, D Bruce-hickman, Sean M. Davidson, Suma P. Kunuthur, Derek M. YellonAbstract:The mitochondrial permeability transition pore (mPTP) is widely accepted as an end-effector mechanism of conditioning protection against injurious ischaemia/reperfusion. However, death can be initiated in cells without pre-requisite mPTP opening, implicating alternate targets for ischaemia/reperfusion injury amelioration. Matrix metalloproteinases (MMP) are known to activate extrinsic apoptotic cascades and therefore we hypothesised that MMP activity represents an mPTP-independent target for augmented attenuation of ischaemia/reperfusion injury. In ex vivo and in vivo mouse hearts, we investigated whether the MMP inhibitor, Ilomastat (0.25 μmol/l), administered upon reperfusion could engender protection in the absence of cyclophilin-D (CyPD), a modulator of mPTP opening, against injurious ischaemia/reperfusion. Ilomastat attenuated infarct size in wild-type (WT) animals [37 ± 2.8 to 22 ± 4.3 %, equivalent to ischaemic postconditioning (iPostC), used as positive control, 27 ± 2.1 %, p < 0.05]. Control CyPD knockout (KO) hearts had smaller infarcts than control WT (28 ± 4.2 %) and iPostC failed to confer additional protection, yet Ilomastat significantly attenuated infarct size in KO hearts (11 ± 3.0 %, p < 0.001), and similar protection was also seen in isolated cardiomyocytes. Moreover, Ilomastat, unlike the cyclophilin inhibitor cyclosporine-A, had no impact upon reactive oxygen species-mediated mPTP opening. While MMP inhibition was associated with increased Akt and ERK phosphorylation, neither Wortmannin nor PD98059 abrogated Ilomastat-mediated protection. We demonstrate that MMP inhibition is cardioprotective, independent of Akt/ERK/CyPD/mPTP activity and is additive to the protection observed following inhibition of mPTP opening, indicative of a parallel pathway to protection in ischaemic/reperfused heart that may have clinical applicability in attenuating injury in acute coronary syndromes and deserve further investigation.
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Matrix metalloproteinase inhibition protects CyPD knockout mice independently of RISK/mPTP signalling: a parallel pathway to protection
Basic Research in Cardiology, 2013Co-Authors: Robert M. Bell, Cara Hendry, D Bruce-hickman, Suma P. Kunuthur, Sean Davidson, Derek M. YellonAbstract:The mitochondrial permeability transition pore (mPTP) is widely accepted as an end-effector mechanism of conditioning protection against injurious ischaemia/reperfusion. However, death can be initiated in cells without pre-requisite mPTP opening, implicating alternate targets for ischaemia/reperfusion injury amelioration. Matrix metalloproteinases (MMP) are known to activate extrinsic apoptotic cascades and therefore we hypothesised that MMP activity represents an mPTP-independent target for augmented attenuation of ischaemia/reperfusion injury. In ex vivo and in vivo mouse hearts, we investigated whether the MMP inhibitor, Ilomastat (0.25 μmol/l), administered upon reperfusion could engender protection in the absence of cyclophilin-D (CyPD), a modulator of mPTP opening, against injurious ischaemia/reperfusion. Ilomastat attenuated infarct size in wild-type (WT) animals [37 ± 2.8 to 22 ± 4.3 %, equivalent to ischaemic postconditioning (iPostC), used as positive control, 27 ± 2.1 %, p
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116 Matrix metalloproteinase inhibition attenuates reperfusion injury, independently of and additive to mitochondrial permeability transition pore inhibition
Heart, 2012Co-Authors: Robert M. Bell, D Bruce-hickman, Sean M. Davidson, R Breckenridge, Cara Hendy, Derek M. YellonAbstract:While matrix-metalloproteinase (MMP) inhibitors appear to protect against myocardial ischaemia/reperfusion injury, the mechanisms are poorly understood. We hypothesised that cardioprotection resultant from MMP inhibition is independent of mitochondrial permeability transition pore (mPTP), the end-effector of ischaemic postconditioning (iPOC). In ex-vivo and in-vivo mouse hearts, we investigated whether the MMP inhibitor, ilomostat (0.25 μmol/l), at the onset of reperfusion, could engender protection in the absence of cyclophillin-D (CyPD), an initiator of mPTP opening, against injurious ischaemia/reperfusion. We have previously demonstrated that CyPD knockout (KO) hearts have inherent resistance to ischaemia/reperfusion injury, and cannot be further protected by either pre or post conditioning regimen. Therefore to further attenuate infarction in this model would require a mechanism independent of the mPTP. We found that Ilomastat attenuated infarct size in wild type (WT) animals (37%±2.8% to 22%±4.3%, equivalent to ischaemic post conditioning (iPostC—6 cycles of 10sec reperfusion/ischaemia), 27%±2.1%, p
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16 Matrix metalloproteinase inhibition is a parallel pathway to protection against reperfusion injury, both independent and additive to mitochondrial permeability transition pore inhibition
Heart, 2011Co-Authors: Robert M. Bell, Cara Hendry, D Bruce-hickman, Sean M. Davidson, R Breckenridge, Derek M. YellonAbstract:While matrix-metalloproteinase (MMP) inhibition protects against myocardial ischaemia/reperfusion injury, the mechanisms are poorly understood. We hypothesised that this cardioprotection is independent of mitochondrial permeability transition pore (mPTP) inhibition, the end-effector of ischaemic postconditioning (iPOC). In ex vivo and in vivo mouse hearts, we investigated whether the MMP inhibitor, ilomostat (0.25 μmol/l), at reperfusion, could engender protection in the absence of cyclophillin-D (CyPD), an initiator of mPTP opening, against injurious ischaemia/reperfusion. Ilomastat attenuated infarct size in wild type (WT) animals (37±2.8 to 22±4.3%, equivalent to iPOC, 27±2.1%, p
Steve Brocchini - One of the best experts on this subject based on the ideXlab platform.
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lc ms analysis to determine the biodistribution of a polymer coated Ilomastat ocular implant
Journal of Pharmaceutical and Biomedical Analysis, 2018Co-Authors: Abeer H A Mohamedahmed, Alastair Lockwood, Peng T Khaw, Steve Brocchini, Hala M Fadda, Shivam Madaan, Kersti KaruAbstract:Abstract Ilomastat is a matrix metalloproteinase inhibitor (MMPi) that has shown the potential to inhibit scarring (fibrosis) by mediating healing after injury or surgery. A long lasting ocular implantable pharmaceutical formulation of Ilomastat is being developed to mediate the healing process to prevent scarring after glaucoma filtration surgery. The Ilomastat implant was coated with water permeable and biocompatible phosphoryl choline polymer (PC1059) displayed extended slow release of Ilomastat in vitro and in vivo. The ocular distribution of Ilomastat from the implant in rabbits at day 30 post surgery was determined by the extraction of Ilomastat and its internal standard marimastat from the ocular tissues, plasma, aqueous humour and vitreous fluid followed by capillary-flow liquid chromatography (cap-LC), the column effluent was directed into a triple quadrupole mass spectrometer operating in product scan mode. The lower limits of quantification (LLOQs) were 0.3 pg/μL for ocular fluids and plasma, and 3 pg/mg for ocular tissues. The extraction recoveries were 90–95% for Ilomastat and its internal standard from ocular tissues. Ilomastat was found in ocular fluids and tissues at day 30 after surgery. The level of Ilomastat was 18 times higher in the aqueous humour than vitreous humour. The concentration ranking of Ilomastat in the ocular tissues was sclera > bleb conjunctiva > conjunctiva (rest of the eye) > cornea. Mass spectrometry analysis to confirm the presence of Ilomastat in the ocular tissues and fluids at day 30 post-surgery establishes the extended release of Ilomastat can be achieved in vivo, which is crucial information for optimisation of the Ilomastat coated implant.
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an Ilomastat cd eye drop formulation to treat ocular scarring
Investigative Ophthalmology & Visual Science, 2017Co-Authors: Abeer H A Mohamedahmed, Alastair Lockwood, He Li, Maryse Bailly, Peng T Khaw, Steve BrocchiniAbstract:PURPOSE: The purpose of this study was to develop a topical matrix metalloproteinase inhibitor preparation for antiscarring therapy. METHODS: The broad spectrum matrix metalloproteinase inhibitor Ilomastat was formulated using 2-hydroxypropyl-β-cyclodextrin in aqueous solution. In vitro activity of Ilomastat-cyclodextrin (Ilomastat-CD) was examined using fibroblasts seeded in collagen. Permeation of Ilomastat-CD eye drop through pig eye conjunctiva was confirmed using Franz diffusion cells. Ilomastat-CD eye drop was applied to rabbit eyes in vivo, and the distribution of Ilomastat in ocular tissues and fluids was determined by liquid chromatography-mass spectroscopy. RESULTS: The aqueous solubility of Ilomastat-CD was ∼1000 μg/mL in water and 1400 μg/mL in PBS (pH 7.4), which is greater than Ilomastat alone (140 and 160 μg/mL in water and PBS, respectively). The in vitro activity of Ilomastat-CD to inhibit collagen contraction in the presence of human Tenon fibroblast cells was unchanged compared to uncomplexed Ilomastat. Topically administered Ilomastat-CD in vivo to rabbit eyes resulted in a therapeutic concentration of Ilomastat being present in the sclera and conjunctiva and within the aqueous humor. CONCLUSIONS: Ilomastat-CD has the potential to be formulated as an eye drop for use as an antifibrotic, which may have implications for the prevention of scarring in many settings, for example glaucoma filtration surgery.
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Molecular dynamic simulations of ocular tablet dissolution
Journal of Chemical Information and Modeling, 2013Co-Authors: Qian Ru, Peng T Khaw, Steve Brocchini, Hala M Fadda, Chung Li, Daniel Paul, Mire ZlohAbstract:Small tablets for implantation into the subconjunctival space in the eye are being developed to inhibit scarring after glaucoma filtration surgery (GFS). There is a need to evaluate drug dissolution at the molecular level to determine how the chemical structure of the active may correlate with dissolution in the nonsink conditions of the conjunctival space. We conducted molecular dynamics simulations to study the dissolution process of tablets derived from two drugs that can inhibit fibrosis after GFS, 5-fluorouracil (5-FU) and the matrix metalloprotease inhibitor (MMPi), Ilomastat. The dissolution was simulated in the presence of simple point charge (SPC) water molecules, and the liquid turnover of the aqueous humor in the subconjunctival space was simulated by removal of the dissolved drug molecules at regular intervals and replacement by new water molecules. At the end of the simulation, the total molecular solvent accessible surface area of 5-FU tablets increased by 60 times more than that of ilomasta...
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Characterisation of Ilomastat for Prolonged Ocular Drug Release
AAPS PharmSciTech, 2012Co-Authors: Gary Parkinson, Alastair Lockwood, Peng T Khaw, Steve Brocchini, Qian Ru, Simon Gaisford, Ashkan Khalili, Rose Sheridan, Hala M FaddaAbstract:We are developing tablet dosage forms for implantation directly into the subconjunctival space of the eye. The matrix metalloproteinase inhibitor, Ilomastat, has previously been shown to be efficacious at suppressing scarring following glaucoma filtration surgery (GFS). We report on the physical characterisation of Ilomastat which is being developed for ocular implantation. Since Ilomastat is being considered for implantation it is necessary to examine its polymorphs and their influence on aspects of the in vitro drug release profile. X-ray powder diffraction identified two polymorphs of Ilomastat from different commercial batches of the compound. Tablets were prepared from the two different polymorphs. Isothermal perfusion calorimetry was used to show that amorphous content is not increased during tablet formulation. The melting points of the two polymorphs are 188 and 208°C as determined by differential scanning calorimetry. Utilising single crystal X-ray diffraction, the structural conformations and packing arrangements of the different polymorphs were determined. The orthorhombic crystal crystallised as a monohydrate while the second monoclinic crystal form is non-solvated. Ilomastat tablets prepared from the two different solid forms exhibited similar drug release profiles in vitro under conditions mimicking the aqueous composition, volume and flow of the subconjunctival space after GFS. This suggests that a reproducible dose at each time point during release after implantation should be achievable in vivo with Ilomastat tablets prepared from the two polymorphs identified.
