coenzyme-q10 and Glaucoma

Glaucoma, a leading cause of irreversible blindness worldwide, is an optic neuropathy characterized by the progressive death of retinal ganglion cells (RGCs). Elevated intraocular pressure (IOP) is recognized as the main risk factor. Despite effective IOP-lowering therapies, the disease progresses in a significant number of patients. Therefore, alternative IOP-independent strategies aiming at halting or delaying RGC degeneration is the current therapeutic challenge for glaucoma management. Here, we review the literature on the neuroprotective activities, and the underlying mechanisms, of natural compounds and dietary supplements in experimental and clinical glaucoma.

Topics: Amides; Biological Products; Colforsin; Curcumin; Cytidine Diphosphate Choline; Dietary Supplements; Ethanolamines; Fatty Acids, Unsaturated; Flavonoids; Ginkgo biloba; Glaucoma; Humans; Melatonin; Neuroprotective Agents; Palmitic Acids; Phytotherapy; Plant Extracts; Resveratrol; Taurine; Tea; Ubiquinone; Vitamins

Mitochondrial function is closely linked to numerous aspects of eye health. Imbalance between the creation of energy and the development of reactive oxygen species (ROS) seems to be the cause of the development of mitochondrial dysfunctions. As a result of this energy deficit, the level of oxidative stress in the eye tissues increases, leading to numerous ophthalmic impairments. It is important to distinguish between primary mitochondrial eye diseases and secondary mitochondrial changes. Primary mitochondrial eye diseases, for example Leber's hereditary optic atrophy (LHON), retinitis pigmentosa and chronic progressive external ophthalmoplegia are caused by direct damage to mitochondrial function induced by defective genes, either located on mitochondrial DNA (mtDNA) or the DNA of the nucleus (nDNA). In contrast, secondary mitochondrial dysfunctions are caused by environmental factors. In recent years, there has been growing evidence that mitochondrial dysfunctions play an important role in many common eye diseases, such as glaucoma, dry eye, diabetic retinopathy, cataract and age-related macular degeneration (AMD). This article summarises current knowledge of mitochondrial dysfunctions and the role of coenzyme Q10 (CoQ10) as a possible treatment option - with a special focus on glaucoma.. Die mitochondriale Funktion ist mit zahlreichen Aspekten der Gesundheit des Auges eng verknüpft. Ursächlich für mitochondriale Dysfunktionen scheint ein Ungleichgewicht zwischen der Bildung von Energie und der Menge an freien Radikalen zu sein. Dadurch kommt es neben einem Energiemangel zu einer erhöhten oxidativen Belastung der betroffenen Augengewebe mit der Folge einer Vielzahl von ophthalmologischen Beeinträchtigungen. Dabei wird zwischen primären und sekundären mitochondrialen Augenerkrankungen unterschieden. Primäre mitochondriale Erkrankungen wie bspw. die Leberʼsche hereditäre Optikusatrophie (LHON), die Retinitis pigmentosa und die chronisch progressive externe Ophthalmoplegie sind die Folge von direkten Schädigungen der mitochondrialen Funktion durch defekte Gene auf der mitochondrialen DNA (mtDNA) oder auf der nukleären DNA (nDNA). Demgegenüber sind sekundäre mitochondriale Dysfunktionen vor allem auf Umwelteinflüsse zurückzuführen. In jüngster Zeit häufen sich Hinweise darauf, dass auch mitochondriale Dysfunktionen bei vielen häufig auftretenden Augenerkrankungen wie dem Glaukom, dem „Trockenen Auge“, der diabetischen Retinopathie, der Katarakt und der altersabhängigen Makuladegeneration (AMD) eine wichtige Rolle spielen. Dieser Beitrag fasst den derzeitigen Kenntnisstand zu mitochondrialen Dysfunktionen und zur Rolle von Coenzym Q10 (CoQ10) als mögliche Therapieoption beim Glaukom zusammen.

Topics: Animals; Biological Availability; Diagnosis, Differential; Disease Models, Animal; Electron Transport; Energy Metabolism; Eye; Free Radicals; Glaucoma; Humans; Microscopy, Electron; Mitochondrial Diseases; Ophthalmic Solutions; Reactive Oxygen Species; Risk Factors; Ubiquinone

The concept that optic nerve fiber loss might be reduced by neuroprotection arose in the mid 1990s. The subsequent research effort, focused mainly on rodent models, has not yet transformed into a successful clinical trial, but provides mechanistic understanding of retinal ganglion cell death and points to potential therapeutic strategies. This review highlights advances made over the last year.. In excitotoxicity and axotomy models retinal ganglion cell death has been shown to result from a complex interaction between retinal neurons and Müller glia, which release toxic molecules including tumor necrosis factor alpha. This counteracts neuroprotection by neurotrophins such as nerve growth factor, which bind to p75NTR receptors on Müller glia stimulating the toxic release. Another negative effect against neurotrophin-mediated protection involves the action of LINGO-1 at trkB brain-derived neurotrophic factor (BDNF) receptors, and BDNF neuroprotection is enhanced by an antagonist to LINGO-1. As an alternative to pharmacotherapy, retinal defences can be stimulated by exposure to infrared radiation.. The mechanisms involved in glaucoma and other optic nerve disorders are being clarified in rodent models, focusing on retrograde degeneration following axonal damage, excitotoxicity and inflammatory/autoimmune mechanisms. Neuroprotective strategies are being refined in the light of the mechanistic understanding.

Topics: Antioxidants; Glaucoma; Humans; Infrared Rays; Intraocular Pressure; Nitric Oxide Synthase; Optic Nerve Diseases; Retinal Ganglion Cells; Ubiquinone

Currently, assessment of new drug efficacy in glaucoma relies on conventional perimetry to monitor visual field changes. However, visual field defects cannot be detected until 20-40% of retinal ganglion cells (RGCs), the key cells implicated in the development of irreversible blindness in glaucoma, have been lost. We have recently developed a new, noninvasive real-time imaging technology, which is named DARC (detection of apoptosing retinal cells), to visualize single RGC undergoing apoptosis, the earliest sign of glaucoma. Utilizing fluorescently labeled annexin 5 and confocal laser scanning ophthalmoscopy, DARC enables evaluation of treatment effectiveness by monitoring RGC apoptosis in the same living eye over time. Using DARC, we have assessed different neuroprotective therapies in glaucoma-related animal models and demonstrated DARC to be a useful tool in screening neuroprotective strategies. DARC will potentially provide a meaningful clinical end point that is based on the direct assessment of the RGC death process, not only being useful in assessing treatment efficacy, but also leading to the early identification of patients with glaucoma. Clinical trials of DARC in glaucoma patients are due to start in 2008.

Topics: Amyloid beta-Peptides; Animals; Apoptosis; Clinical Trials as Topic; Disease Models, Animal; Glaucoma; Glutamic Acid; Humans; Lasers; Neuroprotective Agents; Ophthalmoscopes; Ophthalmoscopy; Retinal Ganglion Cells; Ubiquinone; Visual Field Tests; Visual Fields; Vitamins

We aimed to create mechanic optic nerve injury model in rats and investigate the neuroprotective effects of topical Coenzyme Q10 + Vitamin E (CoQ + Vit.E) molecules on retinal ganglion cells.. Mechanic optic nerve injury model was created in the right eyes of rats (n = 12). Rats were divided into two groups: glaucoma model with sham treatment and topical CoQ + Vit.E treatment. Treatment was applied for 4 weeks. Glial fibrillary acidic protein, Brn-3a antibody, and anti-Iba1 were examined by immunohistochemistry. Glial fibrillary acidic protein, Bax, Bcl-xL, and Tfam protein expression were measured by Western blot analysis.. The number of Brn-3a-positive retinal ganglion cell was 15.0 ± 1.0 (min: 14, max: 16) in sham treatment group and 22.2 ± 4.8 (min: 18, max: 29) in topical CoQ10 + Vit.E treatment group. The protection of Brn-3a in CoQ10 + Vit.E was statistically significant (p < 0.05). Glial fibrillary acidic protein-positive astroglial counts were recorded as 11.7 ± 2.1 (min: 10, max: 14) in sham treatment and 2.5 ± 1.5 (min: 1, max: 4) in topical CoQ10 + Vit.E treatment group (p < 0.05). Topical CoQ10 + Vit.E treatment also decreased Iba1 expression in the retina of mechanic optic nerve injury groups. CoQ10 + Vit.E treatment prevented apoptotic cell death by increasing Bcl-xL protein expression. Also, CoQ10 + Vit.E preserved Tfam protein expression in the retina.. This study has shown that in glaucoma treatment the neuron protecting effect of topical CoQ10 + Vit.E molecules can be valuable.

Topics: Administration, Ophthalmic; Animals; bcl-2-Associated X Protein; bcl-X Protein; Blotting, Western; Calcium-Binding Proteins; Disease Models, Animal; Drug Combinations; Glaucoma; Glial Fibrillary Acidic Protein; Immunohistochemistry; Male; Microfilament Proteins; Neuroprotective Agents; Ophthalmic Solutions; Optic Nerve Injuries; Rats; Rats, Wistar; Retinal Ganglion Cells; Transcription Factor Brn-3A; Ubiquinone; Vitamin E

Glaucoma is a multifactorial neurodegenerative disorder and one of the leading causes of irreversible blindness globally and for which intraocular pressure is the only modifiable risk factor. Although neuroprotective therapies have been suggested to have therapeutic potential, drug delivery for the treatment of ocular disorders such as glaucoma remains an unmet clinical need, further complicated by poor patient compliance with topically applied treatments. In the present study we describe the development of multi-loaded PLGA-microspheres (MSs) incorporating three recognised neuroprotective agents (dexamethasone (DX), melatonin (MEL) and coenzyme Q10 (CoQ10)) in a single formulation (DMQ-MSs) to create a novel sustained-release intraocular drug delivery system (IODDS) for the treatment of glaucoma. MSs were spherical, with a mean particle size of 29.04 ± 1.89 μm rendering them suitable for intravitreal injection using conventional 25G-32G needles. >62% incorporation efficiency was achieved for the three drug cargo and MSs were able to co-deliver the encapsulated active compounds in a sustained manner over 30-days with low burst release. In vitro studies showed DMQ-MSs to be neuroprotective in a glutamate-induced cytotoxicity model (IC

Topics: Animals; Dexamethasone; Disease Models, Animal; Drug Carriers; Drug Compounding; Drug Liberation; Drug Therapy, Combination; Glaucoma; Humans; Injections, Intraocular; Male; Melatonin; Microspheres; Neuroprotective Agents; Polylactic Acid-Polyglycolic Acid Copolymer; Rats; Retina; Transcription Factor Brn-3B; Treatment Outcome; Ubiquinone

To test whether a diet supplemented with coenzyme Q10 (CoQ10) ameliorates glutamate excitotoxicity and oxidative stress-mediated retinal ganglion cell (RGC) degeneration by preventing mitochondrial alterations in the retina of glaucomatous DBA/2J mice.. Preglaucomatous DBA/2J and age-matched control DBA/2J-Gpnmb(+) mice were fed with CoQ10 (1%) or a control diet daily for 6 months. The RGC survival and axon preservation were measured by Brn3a and neurofilament immunohistochemistry and by conventional transmission electron microscopy. Glial fibrillary acidic protein (GFAP), superoxide dismutase-2 (SOD2), heme oxygenase-1 (HO1), N-methyl-d-aspartate receptor (NR) 1 and 2A, and Bax and phosphorylated Bad (pBad) protein expression was measured by Western blot analysis. Apoptotic cell death was assessed by TUNEL staining. Mitochondrial DNA (mtDNA) content and mitochondrial transcription factor A (Tfam)/oxidative phosphorylation (OXPHOS) complex IV protein expression were measured by real-time PCR and Western blot analysis.. Coenzyme Q10 promoted RGC survival by approximately 29% and preserved the axons in the optic nerve head (ONH), as well as inhibited astroglial activation by decreasing GFAP expression in the retina and ONH of glaucomatous DBA/2J mice. Intriguingly, CoQ10 significantly blocked the upregulation of NR1 and NR2A, as well as of SOD2 and HO1 protein expression in the retina of glaucomatous DBA/2J mice. In addition, CoQ10 significantly prevented apoptotic cell death by decreasing Bax protein expression or by increasing pBad protein expression. More importantly, CoQ10 preserved mtDNA content and Tfam/OXPHOS complex IV protein expression in the retina of glaucomatous DBA/2J mice.. Our findings suggest that CoQ10 may be a promising therapeutic strategy for ameliorating glutamate excitotoxicity and oxidative stress in glaucomatous neurodegeneration.

Topics: Animals; Axons; bcl-Associated Death Protein; Blotting, Western; Disease Models, Animal; Female; Glaucoma; Glial Fibrillary Acidic Protein; Glutamic Acid; Heme Oxygenase-1; In Situ Nick-End Labeling; Membrane Proteins; Mice; Mice, Inbred DBA; Mitochondria; Nerve Tissue Proteins; Oxidative Stress; Real-Time Polymerase Chain Reaction; Receptors, N-Methyl-D-Aspartate; Retinal Degeneration; Retinal Ganglion Cells; Superoxide Dismutase; Ubiquinone; Vitamins

Glaucoma is a worldwide leading cause of irreversible vision loss characterized by progressive death of retinal ganglion cells (RGCs). In the course of glaucoma, RGC death may be the consequence of energy impairment that triggers secondary excitotoxicity and free radical generation. There is substantial evidence also that a number of free radical scavengers and/or agents that improve mitochondrial function may be useful as therapies to ameliorate cell death in various neurological disorders including glaucoma. Coenzyme Q10 (CoQ10), an essential cofactor of the electron transport chain, has been reported to afford neuroprotection in neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases, and its protective effect has been attributed in part to its free radical scavenger ability and to a specific regulation of the mitochondrial permeability transition pore. Using an established animal model of transient retinal ischemia, we have conclusively identified a role for abnormal elevation of extracellular glutamate in the mechanisms underlying RGC death that occurs, at least in part, via activation of the apoptotic program. Under these experimental conditions, N-methyl-D-aspartate (NMDA) and non-NMDA subtype of glutamate receptor antagonists, nitric oxide synthase inhibitors, and CoQ10 afford retinal protection supporting an important role for excitotoxicity in the mechanisms underlying RGC death.

Topics: Animals; Calpain; Cell Death; Glaucoma; Glutamic Acid; Humans; Intraocular Pressure; Neuroprotective Agents; Oxidative Stress; Rats; Reperfusion Injury; Retina; Retinal Ganglion Cells; Ubiquinone

Coenzyme Q10 (CoQ10) is an essential component of the mitochondrial membrane and plays an important role in the maintenance of normal cardiac function. To evaluate the effects of ocular timolol on the cardiovascular system and determine the protective effect of CoQ10, 16 patients with glaucoma were studied using impedance cardiography. Following instillation of 1 mg timolol maleate in each eye, heart rate (HR) and stroke index (SI) decreased, and total peripheral resistance index (TPRI) increased significantly. Reexamination was performed after 6 weeks of 90 mg oral CoQ10. Despite decreases in HR, percent changes in HR were significantly less after CoQ10 at 120 min. Stroke index showed an initial increase which was not observed without CoQ10. These data suggest that CoQ10 delayed the appearance of inotropic blockade of timolol and hastened the disappearance of chronotropic blockade. Additional study of six normal volunteers with 6 weeks of oral CoQ10 showed a similar decrease of intraocular pressure after timolol instillation as compared to those without CoQ10. Thus, administration of oral CoQ10 in patients receiving ocular timolol may be useful in mitigating cardiovascular side effects without affecting intraocular pressure in the treatment of glaucoma.

Topics: Administration, Oral; Aged; Blood Pressure; Cardiac Output; Coenzymes; Female; Glaucoma; Heart Rate; Hemodynamics; Humans; Male; Middle Aged; Ophthalmic Solutions; Time Factors; Timolol; Ubiquinone; Vascular Resistance