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Zhang Y, Zhao Z, Ma Q, Li K, Zhao X, Jia Z. Association between dietary calcium, potassium, and magnesium consumption and glaucoma. PLoS One 2023; 18:e0292883. [PMID: 37851631 PMCID: PMC10584168 DOI: 10.1371/journal.pone.0292883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 10/01/2023] [Indexed: 10/20/2023] Open
Abstract
BACKGROUND Calcium (Ca), potassium (K) and magnesium (Mg) may be involved in the occurrence and development of glaucoma by influencing the retinal oxidative stress and regulate blood pressure. However, epidemiological opinions on dietary intake of macroelement related to glaucoma are inconsistent. Herein, this study aims to explore the association between dietary Ca, K, and Mg consumption and glaucoma. METHODS Data of 7,042 adults aged ≥40 years old who received the glaucoma examinations were extracted from the National Health and Nutrition Examination Survey (NHANES) database from 2005 to 2008 in this cross-sectional study. Univariate and multivariate logistic regression were used to explore the association between dietary Ca, K, and Mg intake and glaucoma with the odd ratios (ORs) and 95% confidence intervals (CIs). We also investigated this relationship in individuals of different age, with/without hypertension and visual field defect (VFD). RESULTS There were 502 (8.11%) participants had glaucoma. After adjusted for covariables, we found that enough dietary Ca consumption was related to a decreased risk of glaucoma [OR = 0.59, 95%CI: (0.42-0.81)], whether in persons with/without hypertension (all P<0.05). In particular, dietary K intake may be a potential protect factor for glaucoma in non-hypertension populations [OR = 0.47, 95%CI: (0.22-0.99), P = 0.049]. Additionally, hypertension/non-hypertension persons who aged <65 years old or with/without VFD should all pay attention to the enough dietary supplement of Ca, K, and Mg according to their own circumstances. CONCLUSION Enough dietary Ca, K, and Mg consumption may be potential protect factors of glaucoma that could provide some dietary reference for developing targeted glaucoma prevention and control measures.
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Affiliation(s)
- Yin Zhang
- Department of ophthalmology, Hebei General Hospital, Shijiazhuang, Hebei, P.R. China
| | - Zhihua Zhao
- Department of ophthalmology, Hebei General Hospital, Shijiazhuang, Hebei, P.R. China
| | - Qingmin Ma
- Department of ophthalmology, Hebei General Hospital, Shijiazhuang, Hebei, P.R. China
| | - Kejun Li
- Department of ophthalmology, Hebei General Hospital, Shijiazhuang, Hebei, P.R. China
| | - Xiaobin Zhao
- Department of ophthalmology, Hebei General Hospital, Shijiazhuang, Hebei, P.R. China
| | - Zhiyang Jia
- Department of ophthalmology, Hebei General Hospital, Shijiazhuang, Hebei, P.R. China
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Pervan-Steel CL, Roy Chowdhury U, Sookdeo HK, Casale RA, Dosa PI, Htoo TM, Fautsch MP, Wirostko BM. Ocular Hypotensive Properties and Biochemical Profile of QLS-101, a Novel ATP-Sensitive Potassium (KATP) Channel Opening Prodrug. Invest Ophthalmol Vis Sci 2022; 63:26. [PMID: 35486069 PMCID: PMC9055548 DOI: 10.1167/iovs.63.4.26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 04/10/2022] [Indexed: 11/24/2022] Open
Abstract
Purpose To characterize the ocular hypotensive and pharmacological properties of QLS-101, a novel ATP-sensitive potassium (KATP) channel opening prodrug. Methods Ocular hypotensive properties of QLS-101 were evaluated by measuring IOP with a handheld rebound tonometer after daily topical ocular instillation of 0.2% (n = 5) or 0.4% QLS-101 (n = 10) in C57BL/6J mice. KATP channel specificity was characterized in HEK-293 cells stably expressing human Kir6.2/SUR2B subunits and assessed for off-target interactions using a receptor binding screen. Conversion of QLS-101 prodrug to its active moiety, levcromakalim, was evaluated in vitro using human ocular tissues and plasma samples and after incubation with human phosphatase enzymes (2.0 nM-1.0 µM). Results C57BL/6J mice treated once daily with 0.2% QLS-101 exhibited significant (P < 0.01) IOP reductions of 2.1 ± 0.4 mmHg after five days; however, a daily attenuation of the effect was noted by 23h post-dose. By comparison, treatment with 0.4% QLS-101 lowered IOP by 4.8 ± 0.7 mm Hg (P < 0.0001) which was sustained for 24 hours. Unlike levcromakalim, QLS-101 failed to induce KATP channel activity in HEK-Kir6.2/SUR2B cells consistent with its development as a prodrug. No off-target receptor effects were detected with either compound. In vitro ocular tissue conversion of QLS-101 prodrug was identified in human iris, ciliary body, trabecular meshwork, and sclera. Alkaline phosphatase was found to convert QLS-101 (mean Km = 630 µM, kcat = 15 min-1) to levcromakalim. Conclusions QLS-101 is a novel KATP channel opening prodrug that when converted to levcromakalim shows 24-hour IOP lowering after once-daily topical ocular administration.
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Affiliation(s)
| | - Uttio Roy Chowdhury
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States
| | | | | | - Peter I. Dosa
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota, United States
| | | | - Michael P. Fautsch
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States
| | - Barbara M. Wirostko
- Qlaris Bio, Inc., Wellesley, Massachusetts, United States
- Department of Ophthalmology, Moran Eye Center, University of Utah, Salt Lake City, Utah, United States
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Roy Chowdhury U, Millar JC, Holman BH, Anderson KJ, Dosa PI, Roddy GW, Fautsch MP. Effect of ATP-sensitive Potassium Channel Openers on Intraocular Pressure in Ocular Hypertensive Animal Models. Invest Ophthalmol Vis Sci 2022; 63:15. [PMID: 35129587 PMCID: PMC8822368 DOI: 10.1167/iovs.63.2.15] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Purpose To evaluate the effect of ATP-sensitive potassium channel openers cromakalim prodrug 1 (CKLP1) and diazoxide on IOP in three independent mouse models of ocular hypertension. Methods Baseline IOP was measured in TGFβ2 overexpression, steroid-induced, and iris dispersion (DBA/2J) ocular hypertension mouse models, followed by once daily eyedrop administration with CKLP1 (5 mM) or diazoxide (5 mM). The IOP was measured in conscious animals with a handheld rebound tonometer. Aqueous humor dynamics were assessed by a constant perfusion method. Effect of treatment on ocular tissues was evaluated by transmission electron microscopy. Results CKLP1 decreased the IOP by 20% in TGFβ2 overexpressing mice (n = 6; P < 0.0001), 24% in steroid-induced ocular hypertensive mice (n = 8; P < 0.0001), and 43% in DBA/2J mice (n = 15; P < 0.0001). Diazoxide decreased the IOP by 32% in mice with steroid-induced ocular hypertension (n = 13; P < 0.0001) and by 41% in DBA/2J mice (n = 4; P = 0.005). An analysis of the aqueous humor dynamics revealed that CKLP1 decreased the episcleral venous pressure by 29% in TGFβ2 overexpressing mice (n = 13; P < 0.0001) and by 72% in DBA/2J mice (n = 4 control, 3 treated; P = 0.0002). Diazoxide lowered episcleral venous pressure by 35% in steroid-induced ocular hypertensive mice (n = 3; P = 0.03). Tissue histology and cell morphology appeared normal when compared with controls. Accumulation of extracellular matrix was reduced in CKLP1- and diazoxide-treated eyes in the steroid-induced ocular hypertension model. Conclusions ATP-sensitive potassium channel openers CKLP1 and diazoxide effectively decreased the IOP in ocular hypertensive animal models by decreasing the episcleral venous pressure, supporting a potential therapeutic application of these agents in ocular hypertension and glaucoma.
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Affiliation(s)
| | - J Cameron Millar
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, United States
| | - Bradley H Holman
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, United States
| | | | - Peter I Dosa
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, United States
| | - Gavin W Roddy
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, United States
| | - Michael P Fautsch
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, United States
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Roy Chowdhury U, Kudgus RA, Holman BH, Rinkoski TA, Hann CR, Bahler CK, McCloud E, Appt SE, Reid JM, Dosa PI, Fautsch MP. Pharmacological Profile and Ocular Hypotensive Effects of Cromakalim Prodrug 1, a Novel ATP-Sensitive Potassium Channel Opener, in Normotensive Dogs and Nonhuman Primates. J Ocul Pharmacol Ther 2021; 37:251-260. [PMID: 33784195 PMCID: PMC8215408 DOI: 10.1089/jop.2020.0137] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 02/27/2021] [Indexed: 11/13/2022] Open
Abstract
Purpose: To evaluate pharmacokinetic parameters and ocular hypotensive effects of cromakalim prodrug 1 (CKLP1) in normotensive large animal models. Methods: Optimal CKLP1 concentration was determined by dose response and utilized in short- (5-8 days) and long-term (60 days) evaluation in hound dogs (n = 5) and African Green Monkeys (n = 5). Blood pressure was recorded 3-5 times per week with a tail cuff. Concentrations of CKLP1 and the parent compound levcromakalim were assessed in hound dog plasma and select tissues by LC-MS/MS after bilateral ocular treatment with CKLP1 for 8 days. Pharmacokinetic parameters were calculated from days 1, 4, and 8 data. After necropsy, histology was assessed in 43 tissue samples from each animal. Results: In hound dogs and African Green monkeys, 10 mM CKLP1 (optimal concentration) significantly lowered intraocular pressure (IOP) by 18.9% ± 1.1% and 16.7% ± 6.7%, respectively, compared with control eyes (P < 0.05). During treatment, no significant change in systolic or diastolic blood pressure was observed in either species (P > 0.1). Average values for half-life of CKLP1 was 295.3 ± 140.4 min, Cmax, 10.5 ± 1.6 ng/mL, and area under the concentration vs. time curve (AUClast) 5261.4 ± 918.9 ng·min/mL. For levcromakalim, average values of half-life were 96.2 ± 27 min, Cmax 1.2 ± 0.2 ng/mL, and AUClast 281.2 ± 110.8 ng·min/mL. No significant pathology was identified. Conclusions: CKLP1 lowered IOP in hound dogs and African green monkeys with no effect on systemic blood pressure. Ocular topical treatment of CKLP1 showed excellent tolerability even after extended treatment periods.
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Affiliation(s)
- Uttio Roy Chowdhury
- Department of Ophthalmology, Mayo Clinic Rochester, Rochester, Minnesota, USA
| | - Rachel A. Kudgus
- Department of Oncology Research, Mayo Clinic Rochester, Rochester, Minnesota, USA
| | - Bradley H. Holman
- Department of Ophthalmology, Mayo Clinic Rochester, Rochester, Minnesota, USA
| | - Tommy A. Rinkoski
- Department of Ophthalmology, Mayo Clinic Rochester, Rochester, Minnesota, USA
| | - Cheryl R. Hann
- Department of Ophthalmology, Mayo Clinic Rochester, Rochester, Minnesota, USA
| | - Cindy K. Bahler
- Department of Ophthalmology, Mayo Clinic Rochester, Rochester, Minnesota, USA
| | - Eric McCloud
- Department of Pathology, Section of Comparative Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Susan E. Appt
- Department of Pathology, Section of Comparative Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Joel M. Reid
- Department of Oncology Research, Mayo Clinic Rochester, Rochester, Minnesota, USA
| | - Peter I. Dosa
- Department of Medicinal Chemistry, Institute for Therapeutics Discovery and Development, University of Minnesota, Minneapolis, Minnesota, USA
| | - Michael P. Fautsch
- Department of Ophthalmology, Mayo Clinic Rochester, Rochester, Minnesota, USA
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Roy Chowdhury U, Bahler CK, Hann CR, Holman BH, Fautsch MP. Isolation and characterization of novel primary cells from the human distal outflow pathway. Sci Rep 2021; 11:4034. [PMID: 33597641 PMCID: PMC7890058 DOI: 10.1038/s41598-021-83558-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 02/01/2021] [Indexed: 12/01/2022] Open
Abstract
Ocular hypertension occurs due to increased resistance to aqueous humor removal through the conventional outflow pathway. Unlike the proximal region of the conventional outflow pathway, the distal region has not been well studied, mostly due to lack of model systems. Here we describe isolation and characterization of human primary vascular distal outflow pathway (VDOP) cells from the distal region of the conventional outflow pathway. Tissue from the distal region was isolated from human corneo-scleral rims, digested with collagenase type I (100 U/ml) and placed on gelatin coated plates to allow cellular growth in Dulbecco's Modified Eagle's Medium (low glucose) containing fetal bovine serum and antibiotic/antimycotic. VDOP cells showed consistent proliferation for up to 7 passages, retained endothelial-like nature of the parent tissues and showed a unique marker phenotype of Lectin+VEGFR2-CD34-NG2- that was distinct from neighboring trabecular meshwork (Lectin+VEGFR2-CD34-NG2+) and Schlemm's canal (Lectin+VEGFR2+CD34+NG2+) cells. Dexamethasone treated VDOP cells did not express myocilin and did not form cross-linked actin networks, in contrast to trabecular meshwork cells. These data show that VDOP cells are unique to the distal outflow region and can be used as a viable in vitro model system to understand the biology of the distal outflow pathway and intraocular pressure regulation.
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Affiliation(s)
- Uttio Roy Chowdhury
- Department of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
| | - Cindy K Bahler
- Department of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Cheryl R Hann
- Department of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Bradley H Holman
- Department of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Michael P Fautsch
- Department of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
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Reina-Torres E, Boussommier-Calleja A, Sherwood JM, Overby DR. Aqueous Humor Outflow Requires Active Cellular Metabolism in Mice. Invest Ophthalmol Vis Sci 2021; 61:45. [PMID: 32845955 PMCID: PMC7452856 DOI: 10.1167/iovs.61.10.45] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Purpose Conventional wisdom posits that aqueous humor leaves the eye by passive bulk flow without involving energy-dependent processes. However, recent studies have shown that active processes, such as cell contractility, contribute to outflow regulation. Here, we examine whether inhibiting cellular metabolism affects outflow facility in mice. Methods We measured outflow facility in paired enucleated eyes from C57BL/6J mice using iPerfusion. We had three Experimental Sets: ES1, perfused at 35°C versus 22°C; ES2, perfused with metabolic inhibitors versus vehicle at 35°C; and ES3, perfused at 35°C versus 22°C in the presence of metabolic inhibitors. Inhibitors targeted glycolysis and oxidative phosphorylation (2-deoxy-D-glucose, 3PO and sodium azide). We also measured adenosine triphosphate (ATP) levels in separate murine anterior segments treated like ES1 and ES2. Results Reducing temperature decreased facility by 63% [38%, 78%] (mean [95% confidence interval (CI)], n = 10 pairs; P = 0.002) in ES1 after correcting for changes in viscosity. Metabolic inhibitors reduced facility by 21% [9%, 31%] (n = 9, P = 0.006) in ES2. In the presence of inhibitors, temperature reduction decreased facility by 44% [29%, 56%] (n = 8, P < 0.001) in ES3. Metabolic inhibitors reduced anterior segment adenosine triphosphate (ATP) levels by 90% [83%, 97%] (n = 5, P<<0.001), but reducing temperature did not affect ATP. Conclusions Inhibiting cellular metabolism decreases outflow facility within minutes. This implies that outflow is not entirely passive, but depends partly on energy-dependent cellular processes, at least in mice. This study also suggests that there is a yet unidentified mechanism, which is strongly temperature-dependent but metabolism-independent, that is necessary for nearly half of normal outflow function in mice.
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Affiliation(s)
- Ester Reina-Torres
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | | | - Joseph M Sherwood
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Darryl R Overby
- Department of Bioengineering, Imperial College London, London, United Kingdom
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Kelada M, Hill D, Yap TE, Manzar H, Cordeiro MF. Innovations and revolutions in reducing retinal ganglion cell loss in glaucoma. EXPERT REVIEW OF OPHTHALMOLOGY 2020. [DOI: 10.1080/17469899.2021.1835470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Mary Kelada
- The Imperial College Ophthalmic Research Group (ICORG), Imperial College London NW1 5QH, UK
| | - Daniel Hill
- Glaucoma and Retinal Neurodegeneration Group, UCL Institute of Ophthalmology, London, UK
| | - Timothy E. Yap
- The Imperial College Ophthalmic Research Group (ICORG), Imperial College London NW1 5QH, UK
- The Western Eye Hospital, Imperial College Healthcare NHS Trust (ICHNT), London, UK
| | - Haider Manzar
- The Imperial College Ophthalmic Research Group (ICORG), Imperial College London NW1 5QH, UK
| | - M. Francesca Cordeiro
- The Imperial College Ophthalmic Research Group (ICORG), Imperial College London NW1 5QH, UK
- Glaucoma and Retinal Neurodegeneration Group, UCL Institute of Ophthalmology, London, UK
- The Western Eye Hospital, Imperial College Healthcare NHS Trust (ICHNT), London, UK
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Vernazza S, Tirendi S, Bassi AM, Traverso CE, Saccà SC. Neuroinflammation in Primary Open-Angle Glaucoma. J Clin Med 2020; 9:E3172. [PMID: 33007927 PMCID: PMC7601106 DOI: 10.3390/jcm9103172] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 09/24/2020] [Accepted: 09/28/2020] [Indexed: 12/18/2022] Open
Abstract
Primary open-angle glaucoma (POAG) is the second leading cause of irreversible blindness worldwide. Increasing evidence suggests oxidative damage and immune response defects are key factors contributing to glaucoma onset. Indeed, both the failure of the trabecular meshwork tissue in the conventional outflow pathway and the neuroinflammation process, which drives the neurodegeneration, seem to be linked to the age-related over-production of free radicals (i.e., mitochondrial dysfunction) and to oxidative stress-linked immunostimulatory signaling. Several previous studies have described a wide range of oxidative stress-related makers which are found in glaucomatous patients, including low levels of antioxidant defences, dysfunction/activation of glial cells, the activation of the NF-κB pathway and the up-regulation of pro-inflammatory cytokines, and so on. However, the intraocular pressure is still currently the only risk factor modifiable by medication or glaucoma surgery. This present review aims to summarize the multiple cellular processes, which promote different risk factors in glaucoma including aging, oxidative stress, trabecular meshwork defects, glial activation response, neurodegenerative insults, and the altered regulation of immune response.
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Affiliation(s)
| | - Sara Tirendi
- Department of Experimental Medicine (DIMES), University of Genoa, 16132 Genoa, Italy; (S.T.); (A.M.B.)
- Inter-University Center for the Promotion of the 3Rs Principles in Teaching & Research (Centro 3R), Italy
| | - Anna Maria Bassi
- Department of Experimental Medicine (DIMES), University of Genoa, 16132 Genoa, Italy; (S.T.); (A.M.B.)
- Inter-University Center for the Promotion of the 3Rs Principles in Teaching & Research (Centro 3R), Italy
| | - Carlo Enrico Traverso
- Clinica Oculistica, DiNOGMI, University of Genoa, 16132 Genoa, Italy;
- Ophthalmology Unit, IRCCS-Polyclinic San Martino Hospital, 16132 Genoa, Italy;
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Roy Chowdhury U, Kudgus RA, Rinkoski TA, Holman BH, Bahler CK, Hann CR, Reid JM, Dosa PI, Fautsch MP. Pharmacological and pharmacokinetic profile of the novel ocular hypotensive prodrug CKLP1 in Dutch-belted pigmented rabbits. PLoS One 2020; 15:e0231841. [PMID: 32298376 PMCID: PMC7162492 DOI: 10.1371/journal.pone.0231841] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 04/01/2020] [Indexed: 11/19/2022] Open
Abstract
Elevated intraocular pressure is the only treatable risk factor for glaucoma, an eye disease that is the leading cause of irreversible blindness worldwide. We have identified cromakalim prodrug 1 (CKLP1), a novel water-soluble ATP-sensitive potassium channel opener, as a new ocular hypotensive agent. To evaluate the pharmacokinetic and safety profile of CKLP1 and its parent compound levcromakalim, Dutch-belted pigmented rabbits were treated intravenously (0.25 mg/kg) or topically (10 mM; 4.1 mg/ml) with CKLP1. Body fluids (blood, aqueous and vitreous humor) were collected at multiple time points and evaluated for the presence of CKLP1 and levcromakalim using a liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) based assay. Histology of tissues isolated from Dutch-belted pigmented rabbits treated once daily for 90 days was evaluated in a masked manner by a certified veterinary pathologist. The estimated plasma parameters following intravenous administration of 0.25 mg/kg of CKLP1 showed CKLP1 had a terminal half-life of 61.8 ± 55.2 min, Tmax of 19.8 ± 23.0 min and Cmax of 1968.5 ± 831.0 ng/ml. Levcromakalim had a plasma terminal half-life of 85.0 ± 37.0 min, Tmax of 61.0 ± 32.0 min and Cmax of 10.6 ± 1.2 ng/ml. Topical CKLP1 treatment in the eye showed low levels (<0.3 ng/mL) of levcromakalim in aqueous and vitreous humor, and trace amounts of CKLP1 and levcromakalim in the plasma. No observable histological changes were noted in selected tissues that were examined following topical application of CKLP1 for 90 consecutive days. These results suggest that CKPL1 is converted to levcromakalim in the eye and likely to some extent in the systemic circulation.
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Affiliation(s)
- Uttio Roy Chowdhury
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, United States of America
| | - Rachel A. Kudgus
- Department of Oncology Research, Mayo Clinic, Rochester, MN, United States of America
| | - Tommy A. Rinkoski
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, United States of America
| | - Bradley H. Holman
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, United States of America
| | - Cindy K. Bahler
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, United States of America
| | - Cheryl R. Hann
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, United States of America
| | - Joel M. Reid
- Department of Oncology Research, Mayo Clinic, Rochester, MN, United States of America
| | - Peter I. Dosa
- Department of Medicinal Chemistry, Institute for Therapeutics Discovery and Development, University of Minnesota, Minneapolis, MN, United States of America
| | - Michael P. Fautsch
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, United States of America
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Ameliorative effect of nicorandil in ovarian ischemia-reperfusion-induced injury in rats: role of potassium channel. Naunyn Schmiedebergs Arch Pharmacol 2020; 393:1599-1610. [PMID: 32266443 DOI: 10.1007/s00210-020-01854-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 03/12/2020] [Indexed: 12/14/2022]
Abstract
Ovarian torsion is a gynecological emergency that leads to serious outcomes. Nicorandil (NIC) is an ATP-sensitive potassium (KATP) channel activator that protects the heart from ischemia. The current study aimed to investigate the role and mechanism of action of NIC in ovarian ischemia-reperfusion (OIR) and possible KATP participation. Twenty-four female albino rats were classified into 4 groups: sham control, OIR, OIR + NIC, OIR + NIC+ glibenclamide (GLB) groups. Serum anti-Müllerian hormone (AMH), ovarian malondialdehyde (MDA), total nitrites (NOx) contents, and superoxide dismutase (SOD) activity were evaluated. Bax and Bcl2 mRNA were also assessed. Histological and immunohistochemical (anti-COX-2 and anti CD68) studies were done. The OIR non-treated group showed histopathological ovarian injury with decreased AMH level. Ovarian MDA, NOx, and Bax mRNA and the expression of COX-2 and CD68 were increased; however, SOD activity and Bcl2 mRNA level were decreased by OIR. NIC significantly ameliorated the histopathological ovarian injury with the restoration of AMH level. NIC significantly corrected oxidative stress and apoptotic biomarkers with decreased COX-2 and CD68 immunostaining. GLB co-administration significantly decreased the protection afforded by NIC. These results imply that NIC has a protective role against OIR via antioxidant, anti-inflammatory, and anti-apoptotic effects and such protection relies, at least partially, on the KATP channel.
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Roy Chowdhury U, Dosa PI, Fautsch MP. ATP sensitive potassium channel openers: A new class of ocular hypotensive agents. Exp Eye Res 2019; 178:225. [PMID: 27353766 PMCID: PMC10518901 DOI: 10.1016/j.exer.2016.06.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 06/16/2016] [Indexed: 11/16/2022]
Affiliation(s)
- Uttio Roy Chowdhury
- Department of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, United States.
| | - Peter I Dosa
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota, 717 Delaware Street SE, Minneapolis, MN 55414, United States.
| | - Michael P Fautsch
- Department of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, United States.
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Bucolo C, Platania CBM, Drago F, Bonfiglio V, Reibaldi M, Avitabile T, Uva M. Novel Therapeutics in Glaucoma Management. Curr Neuropharmacol 2018; 16:978-992. [PMID: 28925883 PMCID: PMC6120119 DOI: 10.2174/1570159x15666170915142727] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 06/26/2017] [Accepted: 09/03/2017] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Glaucoma is a progressive optic neuropathy characterized by retinal ganglion cell death and alterations of visual field. Elevated intraocular pressure (IOP) is considered the main risk factor of glaucoma, even though other factors cannot be ruled out, such as epigenetic mechanisms. OBJECTIVE An overview of the ultimate promising experimental drugs to manage glaucoma has been provided. RESULTS In particular, we have focused on purinergic ligands, KATP channel activators, gases (nitric oxide, carbon monoxide and hydrogen sulfide), non-glucocorticoid steroidal compounds, neurotrophic factors, PI3K/Akt activators, citicoline, histone deacetylase inhibitors, cannabinoids, dopamine and serotonin receptors ligands, small interference RNA, and Rho kinase inhibitors. CONCLUSIONS The review has been also endowed of a brief chapter on last reports about potential neuroprotective benefits of anti-glaucoma drugs already present in the market.
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Affiliation(s)
- Claudio Bucolo
- Address correspondence to this author at the Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, Via S. Sofia 97, 95123 Catania, Italy; Tel: +39 095 4781196;
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Roy Chowdhury U, Rinkoski TA, Bahler CK, Millar JC, Bertrand JA, Holman BH, Sherwood JM, Overby DR, Stoltz KL, Dosa PI, Fautsch MP. Effect of Cromakalim Prodrug 1 (CKLP1) on Aqueous Humor Dynamics and Feasibility of Combination Therapy With Existing Ocular Hypotensive Agents. Invest Ophthalmol Vis Sci 2017; 58:5731-5742. [PMID: 29114841 PMCID: PMC5678549 DOI: 10.1167/iovs.17-22538] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Purpose Cromakalim prodrug 1 (CKLP1) is a water-soluble ATP-sensitive potassium channel opener that has shown ocular hypotensive properties in ex vivo and in vivo experimental models. To determine its mechanism of action, we assessed the effect of CKLP1 on aqueous humor dynamics and in combination therapy with existing ocular hypotensive agents. Methods Outflow facility was assessed in C57BL/6 mice by ex vivo eye perfusions and by in vivo constant flow infusion following CKLP1 treatment. Human anterior segments with no trabecular meshwork were evaluated for effect on pressure following CKLP1 treatment. CKLP1 alone and in combination with latanoprost, timolol, and Rho kinase inhibitor Y27632 were evaluated for effect on intraocular pressure in C57BL/6 mice and Dutch-belted pigmented rabbits. Results CKLP1 lowered episcleral venous pressure (control: 8.9 ± 0.1 mm Hg versus treated: 6.2 ± 0.1 mm Hg, P < 0.0001) but had no detectable effect on outflow facility, aqueous humor flow rate, or uveoscleral outflow. Treatment with CKLP1 in human anterior segments without the trabecular meshwork resulted in a 50% ± 9% decrease in pressure, suggesting an effect on the distal portion of the conventional outflow pathway. CKLP1 worked additively with latanoprost, timolol, and Y27632 to lower IOP, presumably owing to combined effects on different aspects of aqueous humor dynamics. Conclusions CKLP1 lowered intraocular pressure by reducing episcleral venous pressure and lowering distal outflow resistance in the conventional outflow pathway. Owing to this unique mechanism of action, CKLP1 works in an additive manner to lower intraocular pressure with latanoprost, timolol, and Rho kinase inhibitor Y27632.
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Affiliation(s)
- Uttio Roy Chowdhury
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States
| | - Tommy A Rinkoski
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States
| | - Cindy K Bahler
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States
| | - J Cameron Millar
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Jacques A Bertrand
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Bradley H Holman
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States
| | - Joseph M Sherwood
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Darryl R Overby
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Kristen L Stoltz
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota, United States
| | - Peter I Dosa
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota, United States
| | - Michael P Fautsch
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States
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Roy Chowdhury U, Bahler CK, Holman BH, Fautsch MP. ATP-sensitive potassium (KATP) channel openers diazoxide and nicorandil lower intraocular pressure by activating the Erk1/2 signaling pathway. PLoS One 2017; 12:e0179345. [PMID: 28594895 PMCID: PMC5464668 DOI: 10.1371/journal.pone.0179345] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 05/26/2017] [Indexed: 01/17/2023] Open
Abstract
Elevated intraocular pressure is the most prevalent and only treatable risk factor for glaucoma, a degenerative disease of the optic nerve. While treatment options to slow disease progression are available, all current therapeutic and surgical treatments have unwanted side effects or limited efficacy, resulting in the need to identify new options. Previous reports from our laboratory have established a novel ocular hypotensive effect of ATP-sensitive potassium channel (KATP) openers including diazoxide (DZ) and nicorandil (NCD). In the current study, we evaluated the role of Erk1/2 signaling pathway in KATP channel opener mediated reduction of intraocular pressure (IOP). Western blot analysis of DZ and NCD treated primary normal trabecular meshwork (NTM) cells, human TM (isolated from perfusion cultures of human anterior segments) and mouse eyes showed increased phosphorylation of Erk1/2 when compared to vehicle treated controls. DZ and NCD mediated pressure reduction (p<0.02) in human anterior segments (n = 7 for DZ, n = 4 for NCD) was abrogated by U0126 (DZ + U0126: -9.7 ± 11.5%, p = 0.11; NCD + U0126: -0.1 ± 11.5%, p = 1.0). In contrast, U0126 had no effect on latanoprostfree acid-induced pressure reduction (-52.5 ± 6.8%, n = 4, p = 0.001). In mice, DZ and NCD reduced IOP (DZ, 14.9 ± 3.8%, NCD, 16.9 ± 2.5%, n = 10, p<0.001), but the pressure reduction was inhibited by U0126 (DZ + U0126, 0.7 ± 3.0%; NCD + U0126, 0.9 ± 2.2%, n = 10, p>0.1). Histologic evaluation of transmission electron micrographs from DZ + U0126 and NCD + U0126 treated eyes revealed no observable morphological changes in the ultrastructure of the conventional outflow pathway. Taken together, the results indicate that the Erk1/2 pathway is necessary for IOP reduction by KATP channel openers DZ and NCD.
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Affiliation(s)
- Uttio Roy Chowdhury
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Cindy K. Bahler
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Bradley H. Holman
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Michael P. Fautsch
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States of America
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Cerebrospinal Fluid Pressure and Glaucoma. CURRENT OPHTHALMOLOGY REPORTS 2016. [DOI: 10.1007/s40135-016-0110-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Parikh HA, Loewen RT, Roy P, Schuman JS, Lathrop KL, Loewen NA. Differential Canalograms Detect Outflow Changes from Trabecular Micro-Bypass Stents and Ab Interno Trabeculectomy. Sci Rep 2016; 6:34705. [PMID: 27811973 PMCID: PMC5095709 DOI: 10.1038/srep34705] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 09/14/2016] [Indexed: 01/22/2023] Open
Abstract
Recently introduced microincisional glaucoma surgeries that enhance conventional outflow offer a favorable risk profile over traditional surgeries, but can be unpredictable. Two paramount challenges are the lack of an adequate training model for angle surgeries and the absence of an intraoperative quantification of surgical success. To address both, we developed an ex vivo training system and a differential, quantitative canalography method that uses slope-adjusted fluorescence intensities of two different chromophores to avoid quenching. We assessed outflow enhancement by trabecular micro-bypass (TMB) implantation or by ab interno trabeculectomy (AIT). In this porcine model, TMB resulted in an insignificant (p > 0.05) outflow increase of 13 ± 5%, 14 ± 8%, 9 ± 3%, and 24 ± 9% in the inferonasal, superonasal, superotemporal, and inferotemporal quadrant, respectively. AIT caused a 100 ± 50% (p = 0.002), 75 ± 28% (p = 0.002), 19 ± 8%, and 40 ± 21% increase in those quadrants. The direct gonioscopy and tactile feedback provided a surgical experience that was very similar to that in human patients. Despite the more narrow and discontinuous circumferential drainage elements in the pig with potential for underperformance or partial stent obstruction, unequivocal patterns of focal outflow enhancement by TMB were seen in this training model. AIT achieved extensive access to outflow pathways beyond the surgical site itself.
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Affiliation(s)
- Hardik A. Parikh
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, United States
- New Jersey Medical School, Rutgers State University of New Jersey, Newark, NJ 07103, United States
| | - Ralitsa T. Loewen
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, United States
| | - Pritha Roy
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, United States
| | - Joel S. Schuman
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, United States
- Department of Ophthalmology, New York University School of Medicine, NY 10016, United States
- Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, PA 15261, United States
| | - Kira L. Lathrop
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, United States
- Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, PA 15261, United States
| | - Nils A. Loewen
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, United States
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Prasanna G, Li B, Mogi M, Rice DS. Pharmacology of novel intraocular pressure-lowering targets that enhance conventional outflow facility: Pitfalls, promises and what lies ahead? Eur J Pharmacol 2016; 787:47-56. [DOI: 10.1016/j.ejphar.2016.03.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 02/15/2016] [Accepted: 03/01/2016] [Indexed: 12/18/2022]
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Panchal SS, Mehta AA, Santani DD. Effect of potassium channel openers in acute and chronic models of glaucoma. Taiwan J Ophthalmol 2016; 6:131-135. [PMID: 29018728 PMCID: PMC5525614 DOI: 10.1016/j.tjo.2016.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 05/09/2016] [Accepted: 05/19/2016] [Indexed: 11/25/2022] Open
Abstract
PURPOSE Glaucoma is characterized by increased intraocular pressure (IOP). The effect of nicorandil and pinacidil on IOP in experimentally induced acute and chronic models of glaucoma and the mechanism of action involved were studied. METHODS New Zealand white rabbits were used for the study. After the measurement of IOP, nicorandil (1%), pinacidil (1%), and pilocarpine as standard (1%) were instilled topically into the left eye. The other eye served as control. Dextrose (5%) was used to induce acute glaucoma. IOP changes were recorded every 15 minutes until the pressure became normal. Freshly prepared α-chymotrypsin solution was introduced in the posterior chamber to induce chronic glaucoma. Rabbits with ocular hypertension were selected for the study. Similar drug solutions were used to study the effect on IOP. Glibenclamide, pilocarpine, and indomethacin (1%) were used to study the mechanism of action of both drugs. The IOPs were measured just prior to drug instillation and at suitable time intervals using a tonometer. RESULTS Pretreatment with topical nicorandil and pinacidil significantly lowered the rise in IOP in the acute model. Nicorandil and pinacidil initially caused rise in IOP for 15-30 minutes in chronic glaucoma. This was followed by reduction in IOP. Pretreatment with indomethacin and pilocarpine did not modify the effect of nicorandil and pinacidil on IOP. Pretreatment with glibenclamide blocked IOP from the lowering effect of nicorandil and pinacidil. CONCLUSION The oculohypotensive effect shown by these drugs appears to be attributable to enhancement of the aqueous humor outflow. This effect is perhaps mediated through potassium channels.
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Affiliation(s)
- Shital S Panchal
- Department of Pharmacology, Institute of Pharmacy, Nirma University, Ahmedabad 382481, Gujarat, India
| | - Anita A Mehta
- Department of Pharmacology, L.M. College of Pharmacy, Navarangpura, Ahmedabad 9, Gujarat, India
| | - Devdas D Santani
- Department of Pharmacy, NIMS University, Shobha Nagar, Jaipure-Delhi Highway (NH-11C), Jaipur 303121, Rajasthan, India
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Roy Chowdhury U, Viker KB, Stoltz KL, Holman BH, Fautsch MP, Dosa PI. Analogs of the ATP-Sensitive Potassium (KATP) Channel Opener Cromakalim with in Vivo Ocular Hypotensive Activity. J Med Chem 2016; 59:6221-31. [PMID: 27367033 DOI: 10.1021/acs.jmedchem.6b00406] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
ATP-sensitive potassium (KATP) channel openers have emerged as potential therapeutics for the treatment of glaucoma, lowering intraocular pressure (IOP) in animal models and cultured human anterior segments. We have prepared water-soluble phosphate and dipeptide derivatives of the KATP channel opener cromakalim and evaluated their IOP lowering capabilities in vivo. In general, the phosphate derivatives proved to be more chemically robust and efficacious at lowering IOP with once daily dosing in a normotensive mouse model. Two of these phosphate derivatives were further evaluated in a normotensive rabbit model, with a significant difference in activity observed. No toxic effects on cell structure or alterations in morphology of the aqueous humor outflow pathway were observed after treatment with the most efficacious compound, (3S,4R)-2, suggesting that it is a strong candidate for development as an ocular hypotensive agent.
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Affiliation(s)
- Uttio Roy Chowdhury
- Department of Ophthalmology, Mayo Clinic , 200 1st St SW, Rochester, Minnesota 55905, United States
| | - Kimberly B Viker
- Department of Ophthalmology, Mayo Clinic , 200 1st St SW, Rochester, Minnesota 55905, United States
| | - Kristen L Stoltz
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota , 717 Delaware Street SE, Minneapolis, Minnesota 55414, United States
| | - Bradley H Holman
- Department of Ophthalmology, Mayo Clinic , 200 1st St SW, Rochester, Minnesota 55905, United States
| | - Michael P Fautsch
- Department of Ophthalmology, Mayo Clinic , 200 1st St SW, Rochester, Minnesota 55905, United States
| | - Peter I Dosa
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota , 717 Delaware Street SE, Minneapolis, Minnesota 55414, United States
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Roy Chowdhury U, Dosa PI, Fautsch MP. ATP sensitive potassium channel openers: A new class of ocular hypotensive agents. Exp Eye Res 2016; 158:85-93. [PMID: 27130546 DOI: 10.1016/j.exer.2016.04.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 04/22/2016] [Accepted: 04/25/2016] [Indexed: 12/25/2022]
Abstract
ATP sensitive potassium (KATP) channels connect the metabolic and energetic state of cells due to their sensitivity to ATP and ADP concentrations. KATP channels have been identified in multiple tissues and organs of the body including heart, pancreas, vascular smooth muscles and skeletal muscles. These channels are obligatory hetero-octamers and contain four sulfonylurea (SUR) and four potassium inward rectifier (Kir) subunits. Based on the particular type of SUR and Kir present, there are several tissue specific subtypes of KATP channels, each with their own unique set of functions. Recently, KATP channels have been reported in human and mouse ocular tissues. In ex vivo and in vivo model systems, KATP channel openers showed significant ocular hypotensive properties with no appearance of toxic side effects. Additionally, when used in conjunction with known intraocular pressure lowering drugs, an additive effect on IOP reduction was observed. These KATP channel openers have also been reported to protect the retinal ganglion cells during ischemic stress and glutamate induced toxicity suggesting a neuroprotective property for this drug class. Medications that are currently used for treating ocular hypertensive diseases like glaucoma do not directly protect the affected retinal cells, are sometimes ineffective and may show significant side effects. In light of this, KATP channel openers with both ocular hypotensive and neuroprotective properties, have the potential to develop into a new class of glaucoma therapeutics.
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Affiliation(s)
- Uttio Roy Chowdhury
- Dept. of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, United States.
| | - Peter I Dosa
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota, 717 Delaware Street SE, Minneapolis, MN 55414, United States.
| | - Michael P Fautsch
- Dept. of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, United States.
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Giblin JP, Comes N, Strauss O, Gasull X. Ion Channels in the Eye: Involvement in Ocular Pathologies. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2015; 104:157-231. [PMID: 27038375 DOI: 10.1016/bs.apcsb.2015.11.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The eye is the sensory organ of vision. There, the retina transforms photons into electrical signals that are sent to higher brain areas to produce visual sensations. In the light path to the retina, different types of cells and tissues are involved in maintaining the transparency of avascular structures like the cornea or lens, while others, like the retinal pigment epithelium, have a critical role in the maintenance of photoreceptor function by regenerating the visual pigment. Here, we have reviewed the roles of different ion channels expressed in ocular tissues (cornea, conjunctiva and neurons innervating the ocular surface, lens, retina, retinal pigment epithelium, and the inflow and outflow systems of the aqueous humor) that are involved in ocular disease pathophysiologies and those whose deletion or pharmacological modulation leads to specific diseases of the eye. These include pathologies such as retinitis pigmentosa, macular degeneration, achromatopsia, glaucoma, cataracts, dry eye, or keratoconjunctivitis among others. Several disease-associated ion channels are potential targets for pharmacological intervention or other therapeutic approaches, thus highlighting the importance of these channels in ocular physiology and pathophysiology.
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Affiliation(s)
- Jonathan P Giblin
- Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Nuria Comes
- Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | | | - Xavier Gasull
- Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.
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Roy Chowdhury U, Bahler CK, Holman BH, Dosa PI, Fautsch MP. Ocular Hypotensive Effects of the ATP-Sensitive Potassium Channel Opener Cromakalim in Human and Murine Experimental Model Systems. PLoS One 2015; 10:e0141783. [PMID: 26535899 PMCID: PMC4633217 DOI: 10.1371/journal.pone.0141783] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 10/13/2015] [Indexed: 11/17/2022] Open
Abstract
Elevated intraocular pressure (IOP) is the most prevalent and only treatable risk factor for glaucoma, a leading cause of irreversible blindness worldwide. Unfortunately, all current therapeutics used to treat elevated IOP and glaucoma have significant and sometimes irreversible side effects necessitating the development of novel compounds. We evaluated the IOP lowering ability of the broad spectrum KATP channel opener cromakalim. Cultured human anterior segments when treated with 2 μM cromakalim showed a decrease in pressure (19.33 ± 2.78 mmHg at 0 hours to 13.22 ± 2.64 mmHg at 24 hours; p<0.001) when compared to vehicle treated controls (15.89 ± 5.33 mmHg at 0 h to 15.56 ± 4.88 mmHg at 24 hours; p = 0.89). In wild-type C57BL/6 mice, cromakalim reduced IOP by 18.75 ± 2.22% compared to vehicle treated contralateral eyes (17.01 ± 0.32 mmHg at 0 hours to 13.82 ± 0.37 mmHg at 24 hours; n = 10, p = 0.002). Cromakalim demonstrated an additive effect when used in conjunction with latanoprost free acid, a common ocular hypotensive drug prescribed to patients with elevated IOP. To examine KATP channel subunit specificity, Kir6.2(-/-) mice were treated with cromakalim, but unlike wild-type animals, no change in IOP was noted. Histologic analysis of treated and control eyes in cultured human anterior segments and in mice showed similar cell numbers and extracellular matrix integrity within the trabecular meshwork, with no disruptions in the inner and outer walls of Schlemm's canal. Together, these studies suggest that cromakalim is a potent ocular hypotensive agent that lowers IOP via activation of Kir6.2 containing KATP channels, its effect is additive when used in combination with the commonly used glaucoma drug latanoprost, and is not toxic to cells and tissues of the aqueous humor outflow pathway, making it a candidate for future therapeutic development.
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Affiliation(s)
- Uttio Roy Chowdhury
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, United States of America
| | - Cindy K Bahler
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, United States of America
| | - Bradley H Holman
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, United States of America
| | - Peter I Dosa
- Institute for Therapeutics Discovery and Development, University of Minnesota, Minneapolis, MN, United States of America
| | - Michael P Fautsch
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, United States of America
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Abstract
Glaucoma is increasingly recognized as a neurodegenerative disorder, characterized by the accelerated loss of retinal ganglion cells (RGCs) and their axons. Impaired axonal transport has been implicated as a pathogenic mechanism in a number of neurodegenerative diseases, including glaucoma. The long RGC axon, with its high metabolic demand and crucial role in conveying neurotrophic signals, relies heavily on intact axonal transport. In this mini review, we consider the evidence for transport disruption along RGCs in association with glaucoma and other intraocular pressure models. We give a brief overview of the axonal transport process and the methods by which it is assessed. Spatial and temporal patterns of axonal transport disruption are considered as well as the reversibility of these changes. Biomechanical, metabolic and cytoskeletal insults may underlie the development of axonal transport deficits, and there are multiple perspectives on the impact that transport disruption has on the RGC. Eliciting the role of impaired axonal transport in glaucoma pathogenesis may uncover novel therapeutic targets for protecting the optic nerve and preventing vision loss in glaucoma.
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Affiliation(s)
- Eamonn T Fahy
- a Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne , Melbourne , Victoria , Australia
| | - Vicki Chrysostomou
- a Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne , Melbourne , Victoria , Australia
| | - Jonathan G Crowston
- a Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne , Melbourne , Victoria , Australia
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César IC, Godin AM, Araujo DP, Oliveira FC, Menezes RR, Santos JR, Almeida MO, Dutra MM, Santos DA, Machado RR, Pianetti GA, Coelho MM, de Fátima Â. Synthesis, antinociceptive activity and pharmacokinetic profiles of nicorandil and its isomers. Bioorg Med Chem 2014; 22:2783-90. [DOI: 10.1016/j.bmc.2014.03.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 02/24/2014] [Accepted: 03/08/2014] [Indexed: 11/29/2022]
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Roy Chowdhury U, Holman BH, Fautsch MP. A novel rat model to study the role of intracranial pressure modulation on optic neuropathies. PLoS One 2013; 8:e82151. [PMID: 24367501 PMCID: PMC3867329 DOI: 10.1371/journal.pone.0082151] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/29/2013] [Indexed: 11/18/2022] Open
Abstract
Reduced intracranial pressure is considered a risk factor for glaucomatous optic neuropathies. All current data supporting intracranial pressure as a glaucoma risk factor comes from retrospective and prospective studies. Unfortunately, there are no relevant animal models for investigating this link experimentally. Here we report a novel rat model that can be used to study the role of intracranial pressure modulation on optic neuropathies. Stainless steel cannulae were inserted into the cisterna magna or the lateral ventricle of Sprague-Dawley and Brown Norway rats. The cannula was attached to a pressure transducer connected to a computer that recorded intracranial pressure in real-time. Intracranial pressure was modulated manually by adjusting the height of a column filled with artificial cerebrospinal fluid in relation to the animal’s head. After data collection the morphological appearance of the brain tissue was analyzed. Based on ease of surgery and ability to retain the cannula, Brown Norway rats with the cannula implanted in the lateral ventricle were selected for further studies. Baseline intracranial pressure for rats was 5.5±1.5 cm water (n=5). Lowering of the artificial cerebrospinal fluid column by 2 cm and 4 cm below head level reduced ICP to 3.7±1.0 cm water (n=5) and 1.5±0.6 cm water (n=4), a reduction of 33.0% and 72.7% below baseline. Raising the cerebrospinal fluid column by 4 cm increased ICP to 7.5±1.4 cm water (n=2) corresponding to a 38.3% increase in intracranial pressure. Histological studies confirmed correct cannula placement and indicated minimal invasive damage to brain tissues. Our data suggests that the intraventricular cannula model is a unique and viable model that can be used to study the effect of altered intracranial pressure on glaucomatous optic neuropathies.
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Affiliation(s)
- Uttio Roy Chowdhury
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Bradley H. Holman
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Michael P. Fautsch
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States of America
- * E-mail:
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Janssen SF, Gorgels TG, van der Spek PJ, Jansonius NM, Bergen AA. In silico analysis of the molecular machinery underlying aqueous humor production: potential implications for glaucoma. J Clin Bioinforma 2013; 3:21. [PMID: 24165276 PMCID: PMC3875900 DOI: 10.1186/2043-9113-3-21] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 10/23/2013] [Indexed: 12/03/2022] Open
Abstract
Background The ciliary body epithelia (CBE) of the eye produce the aqueous humor (AH). The equilibrium between the AH production by the CBE and the outflow through the trabecular meshwork ultimately determines the intraocular pressure (IOP). An increased IOP is a major risk factor for primary open angle glaucoma (POAG). This study aims to elucidate the molecular machinery of the most important function of the CBE: the AH production and composition, and aims to find possible new molecular clues for POAG and AH production-lowering drugs. Methods We performed a gene expression analysis of the non-pigmented (NPE) and pigmented epithelia (PE) of the human CBE of post mortem eyes. We used 44 k Agilent microarrays against a common reference design. Functional annotations were performed with the Ingenuity knowledge database. Results We built a molecular model of AH production by combining previously published physiological data with our current genomic expression data. Next, we investigated molecular CBE transport features which might influence AH composition. These features included caveolin- and clathrin vesicle-mediated transport of large biomolecules, as well as a range of substrate specific transporters. The presence of these transporters implies that, for example, immunoglobins, thyroid hormone, prostaglandins, cholesterol and vitamins can be secreted by the CBE along with the AH. In silico, we predicted some of the molecular apical interactions between the NPE and PE, the side where the two folded epithelia face each other. Finally, we found high expression of seven POAG disease genes in the plasma membrane of extracellular space of the CBE, namely APOE, CAV1, COL8A2, EDNRA, FBN1, RFTN1 and TLR4 and we found possible new targets for AH lowering drugs in the AH. Conclusions The CBE expresses many transporters, which account for AH production and/or composition. Some of these entries have also been associated with POAG. We hypothesize that the CBE may play a more prominent role than currently thought in the pathogenesis of POAG, for example by changing the composition of AH.
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Affiliation(s)
| | | | | | | | - Arthur Ab Bergen
- Department of Clinical and Molecular Ophthalmogenetics the Netherlands Institute for Neuroscience (NIN), Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, the Netherlands.
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Chowdhury UR, Holman BH, Fautsch MP. ATP-sensitive potassium (K(ATP)) channel openers diazoxide and nicorandil lower intraocular pressure in vivo. Invest Ophthalmol Vis Sci 2013; 54:4892-9. [PMID: 23778875 DOI: 10.1167/iovs.13-11872] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
PURPOSE To evaluate the expression of ATP-sensitive potassium (K(ATP)) channel subunits and study the effect of K(ATP) channel openers diazoxide and nicorandil on intraocular pressure (IOP) in an in vivo mouse model. METHODS Expression of K(ATP) channel subunits in normal C57BL/6 mouse eyes was studied by immunohistochemistry and confocal microscopy. Wild-type C57BL/6 mice were treated with K(ATP) channel openers diazoxide (n = 10) and nicorandil (n = 10) for 14 days. Similar treatments with diazoxide were performed on K(ir)6.2((-/-)) mice (n = 10). IOP was recorded with a handheld tonometer 1 hour, 4 hours, and 23 hours following daily treatment. Posttreatment histology was examined by light and transmission electron microscopy. RESULTS The K(ATP) channel subunits SUR2B, K(ir)6.1, and K(ir)6.2 were identified in all tissues within mouse eyes. Treatment with diazoxide in wild-type mice decreased IOP by 21.5 ± 3.2% with an absolute IOP reduction of 3.9 ± 0.6 mm Hg (P = 0.002). Nicorandil also decreased IOP (18.9 ± 1.8%) with an absolute IOP reduction of 3.4 ± 0.4 mm Hg (P = 0.002). Treatment with diazoxide in K(ir)6.2((-/-)) mice had no effect on IOP. No morphological abnormalities were observed in diazoxide- or nicorandil-treated eyes. CONCLUSIONS K(ATP) channel openers diazoxide and nicorandil are effective regulators of IOP in mouse eyes. K(ir)6.2 appears to be a major K(ATP) channel subunit through which IOP is lowered following treatment with diazoxide.
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Affiliation(s)
- Uttio Roy Chowdhury
- Department of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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Abdel-Raheem IT, Taye A, Abouzied MM. Cardioprotective Effects of Nicorandil, a Mitochondrial Potassium Channel Opener against Doxorubicin-Induced Cardiotoxicity in Rats. Basic Clin Pharmacol Toxicol 2013; 113:158-66. [DOI: 10.1111/bcpt.12078] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Accepted: 04/02/2013] [Indexed: 12/31/2022]
Affiliation(s)
- Ihab T. Abdel-Raheem
- Department of Pharmacology and Toxicology; Faculty of Pharmacy; Damanhour University; Damanhour; Egypt
| | - Ashraf Taye
- Department of Pharmacology and Toxicology; Faculty of Pharmacy; Minia University; Minia; Egypt
| | - Mekky M. Abouzied
- Department of Biochemistry; Faculty of Pharmacy; Minia University; Minia; Egypt
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Abstract
PURPOSE OF REVIEW Regulation of intraocular pressure by the conventional (trabecular) outflow pathway is complicated, involving a myriad of mechanical and chemical signals. In most, intraocular pressure is maintained within a tight range over a lifetime. Unfortunately in some, dysfunction results in ocular hypertension and open-angle glaucoma. In the context of established knowledge, this review summarizes recent investigations of conventional outflow function, with the goal of identifying areas for future inquiry and therapeutic targeting. RECENT FINDINGS Mechanical stimulation of conventional outflow cells due to intraocular pressure fluctuations impacts contractility, gene expression, pore formation, enzyme activity, and signaling. Numerous local signaling mediators in the conventional pathway such as bioactive lipids, cytokines, nitric oxide, and nucleotides participate in the regulation of outflow. Interestingly outflow through the conventional pathway is not uniform, but segmental, with passageways constantly changing due to focal protease activity of trabecular cells clearing extracellular matrix materials. The relationship between extracellular matrix expression and trabecular meshwork contractility appears to coordinately impact outflow resistance and is the target of a new class of drugs, the Rho kinase inhibitors. SUMMARY The conventional outflow pathway is a dynamic, pressure-sensitive tissue that is vulnerable to pathology on many fronts, each representing a therapeutic opportunity.
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