1
|
Ma C, Li H, Lu S, Li X. The Role and Therapeutic Potential of Melatonin in Degenerative Fundus Diseases: Diabetes Retinopathy and Age-Related Macular Degeneration. Drug Des Devel Ther 2024; 18:2329-2346. [PMID: 38911030 PMCID: PMC11193467 DOI: 10.2147/dddt.s471525] [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: 03/30/2024] [Accepted: 06/13/2024] [Indexed: 06/25/2024] Open
Abstract
Degenerative fundus disease encompasses a spectrum of ocular diseases, including diabetic retinopathy (DR) and age-related macular degeneration (AMD), which are major contributors to visual impairment and blindness worldwide. The development and implementation of effective strategies for managing and preventing the onset and progression of these diseases are crucial for preserving patients' visual acuity. Melatonin, a neurohormone primarily produced by the pineal gland, exhibits properties such as circadian rhythm modulation, antioxidant activity, anti-inflammatory effects, and neuroprotection within the ocular environment. Furthermore, melatonin has been shown to suppress neovascularization and reduce vascular leakage, both of which are critical in the pathogenesis of degenerative fundus lesions. Consequently, melatonin emerges as a promising therapeutic candidate for degenerative ocular diseases. This review provides a comprehensive overview of melatonin synthesis, its localization within ocular tissues, and its mechanisms of action, particularly in regulating melatonin production, thereby underscoring its potential as a therapeutic agent for degenerative fundus diseases.
Collapse
Affiliation(s)
- Chao Ma
- Department of Ophthalmology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, People’s Republic of China
| | - Haoyu Li
- Department of Ophthalmology, the Second Xiangya Hospital, Central South University, Changsha, Hunan, People’s Republic of China
- Hunan Clinical Research Centre of Ophthalmic Disease, Changsha, Hunan, People’s Republic of China
| | - Shuwen Lu
- Department of Ophthalmology, the First Affiliated Hospital of Henan University of Chinese Medicine, Zhengzhou, Henan, People’s Republic of China
| | - Xian Li
- Manchester Royal Eye Hospital, Manchester University NHS Foundation Trust, Manchester, UK
- Division of Pharmacy and Optometry, School of Health Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| |
Collapse
|
2
|
Li KL, Shan SW, Lin FY, Ling CY, Wong NW, Li HL, Han W, To CH, Do CW. Regulation of Aqueous Humor Secretion by Melatonin in Porcine Ciliary Epithelium. Int J Mol Sci 2023; 24:5789. [PMID: 36982863 PMCID: PMC10051954 DOI: 10.3390/ijms24065789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/10/2023] [Accepted: 03/16/2023] [Indexed: 03/30/2023] Open
Abstract
Secretion of melatonin, a natural hormone whose receptors are present in the ciliary epithelium, displays diurnal variation in the aqueous humor (AH), potentially contributing to the regulation of intraocular pressure. This study aimed to determine the effects of melatonin on AH secretion in porcine ciliary epithelium. The addition of 100 µM melatonin to both sides of the epithelium significantly increased the short-circuit current (Isc) by ~40%. Stromal administration alone had no effect on the Isc, but aqueous application triggered a 40% increase in Isc, similar to that of bilateral application without additive effect. Pre-treatment with niflumic acid abolished melatonin-induced Isc stimulation. More importantly, melatonin stimulated the fluid secretion across the intact ciliary epithelium by ~80% and elicited a sustained increase (~50-60%) in gap junctional permeability between pigmented ciliary epithelial (PE) cells and non-pigmented ciliary epithelial (NPE) cells. The expression of MT3 receptor was found to be >10-fold higher than that of MT1 and MT2 in porcine ciliary epithelium. Aqueous pre-treatment with MT1/MT2 antagonist luzindole failed to inhibit the melatonin-induced Isc response, while MT3 antagonist prazosin pre-treatment abolished the Isc stimulation. We conclude that melatonin facilitates Cl- and fluid movement from PE to NPE cells, thereby stimulating AH secretion via NPE-cell MT3 receptors.
Collapse
Affiliation(s)
- Ka-Lok Li
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China
| | - Sze-Wan Shan
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China
- Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Hong Kong, China
- Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Hong Kong, China
| | - Fang-Yu Lin
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China
- Department of Ophthalmology, Zhejiang University, Hangzhou 310027, China
- Department of Ophthalmology, Emory University, Atlanta, GA 30322, USA
| | - Choi-Ying Ling
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China
| | - Nga-Wai Wong
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China
| | - Hoi-Lam Li
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China
- Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Hong Kong, China
| | - Wei Han
- Department of Ophthalmology, Zhejiang University, Hangzhou 310027, China
| | - Chi-Ho To
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China
- Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Hong Kong, China
- Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Hong Kong, China
| | - Chi-Wai Do
- School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China
- Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Hong Kong, China
- Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Hong Kong, China
- Research Institute of Smart Ageing (RISA), The Hong Kong Polytechnic University, Hong Kong, China
| |
Collapse
|
3
|
Liu R, Li J, Xu Y, Chen Z, Ye H, Tang J, Wei L, Liang L. Melatonin Attenuates LPS-Induced Proinflammatory Cytokine Response and Lipogenesis in Human Meibomian Gland Epithelial Cells via MAPK/NF-κB Pathway. Invest Ophthalmol Vis Sci 2022; 63:6. [PMID: 35506935 PMCID: PMC9078073 DOI: 10.1167/iovs.63.5.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Inflammation contributes to the development of meibomian gland dysfunction (MGD) under specific disease conditions, but the underlying mechanisms remain elusive. We examined whether lipopolysaccharide (LPS) induced a proinflammatory cytokine response and lipogenesis in human meibomian gland epithelial cells (HMGECs) and whether melatonin (MLT), a powerful anti-inflammatory regent in the eyes, could protect against LPS-induced disorders. Methods Human meibomian gland (MG) tissues and immortalized HMGECs were stained to identify Toll-like receptor (TLR) 4 and MLT receptors (MT1 and MT2). HMGECs were pretreated with or without MLT and then stimulated with LPS. Then, TLR4 activation, cytokine levels, lipid synthesis, apoptosis, autophagy, and MAPK/NF-κB factor phosphorylation in HMGECs were analyzed. Results TLR4, MT1, and MT2 were expressed in human MG acini and HMGECs. Pretreatment with MLT inhibited the TLR4/MyD88 signaling and attenuated proinflammatory cytokine response and lipogenesis in LPS-stimulated HMGECs, which manifested as decreased production of cytokines (IL-1β, IL-6, IL-8, and TNF-α), reduced lipid droplet formation, and downregulated expression of meibum lipogenic proteins (ADFP, ELOVL4, and SREBP-1). Phospho-histone H2A.X foci, lysosome accumulation, and cytoplasmic cleaved caspase 3/LC3B-II staining were increased in LPS-stimulated HMGECs, indicating enhanced cell death mediated by apoptosis and autophagy during LPS-induced lipogenesis. MLT downregulated cleaved caspase 3 levels and the Bax/Bcl-2 ratio to alleviate apoptosis and ameliorated the expression of Beclin 1 and LC3B-II to inhibit autophagy. The protective mechanisms of MLT include the inhibition of MAPK and NF-κB phosphorylation. Conclusions MLT attenuated lipogenesis, apoptosis, and autophagy in HMGECs induced by proinflammatory stimuli, indicating the protective potential of MLT in MGD.
Collapse
Affiliation(s)
- Ren Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Jing Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yue Xu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Ziyan Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Huijing Ye
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Jinhui Tang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Lai Wei
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Lingyi Liang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| |
Collapse
|
4
|
Ostrin LA. Ocular and systemic melatonin and the influence of light exposure. Clin Exp Optom 2021; 102:99-108. [DOI: 10.1111/cxo.12824] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 07/09/2018] [Accepted: 07/09/2018] [Indexed: 12/15/2022] Open
Affiliation(s)
- Lisa A Ostrin
- University of Houston College of Optometry, Houston, Texas, USA,
| |
Collapse
|
5
|
Melatonin Levels in Patients With Primary Open-angle Glaucoma With High or Low Intraocular Pressure. J Glaucoma 2019; 28:154-160. [DOI: 10.1097/ijg.0000000000001130] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
6
|
Gubin DG, Malishevskaya ТN, Astakhov YS, Astakhov SY, Cornelissen G, Kuznetsov VA, Weinert D. Progressive retinal ganglion cell loss in primary open-angle glaucoma is associated with temperature circadian rhythm phase delay and compromised sleep. Chronobiol Int 2019; 36:564-577. [PMID: 30663431 DOI: 10.1080/07420528.2019.1566741] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Advanced primary open-angle glaucoma (POAG) is characterized by progressive retinal ganglion cell complex (RGCC) damage that may cause subsequent disruption of the circadian rhythms. Therefore, we evaluated circadian body temperature (BT) rhythm and sleep characteristics of 115 individuals (38 men and 77 women) diagnosed with POAG. GLV (global loss volume; %), a measure of RGCC damage, was estimated by high-definition optical coherence tomography, and RGC functional ability was assessed by pattern electroretinogram amplitude (PERGA). Depending on dynamics of POAG progression criteria, two groups were formed that were distinctively different in GLV: Stable POAG group (S-POAG; GLV = 5.95 ± 1.84, n = 65) and Progressive POAG group (P-POAG; GLV = 24.27 ± 5.09, n = 50). S-POAG and P-POAG groups were not different in mean age (67.61 ± 7.56 versus 69.98 ± 8.15) or body mass index (24.66 ± 3.03 versus 24.77 ± 2.90). All subjects performed 21 around-the-clock BT self-measurements during a 72-h period and kept activity/sleep diaries. Results showed pronounced disruption of circadian physiology in POAG and its progression with increasing severity of the disease. The daily mean of BT was unusually low, compared to age-matched controls. Moreover, our results revealed distinctive features of BT circadian rhythm alterations in POAG development and POAG progression. S-POAG is associated with lowered BT circadian rhythm robustness and inter-daily phase stability compared to controls. In the P-POAG group, the mean phase of the circadian BT rhythm was delayed by about 5 h and phases were highly scattered among individual patients, which led to reduced group mean amplitude. Circadian amplitudes of individuals were not different between the groups. Altogether, these results suggest that the body clock still works in POAG patients, but its entrainment to the 24-h environment is compromised. Probably because of the internal desynchronization, bedtime is delayed, and sleep duration is accordingly shortened by about 55 min in P-POAG compared to S-POAG patients. In the entire POAG cohort (both groups), later sleep phase and shorter mean sleep duration correlate with the delayed BT phase (r = 0.215; p = 0.021 and r = 0.322; p = 0.0004, respectively). An RGCC GLV of 15% apparently constitutes a threshold above which a delay of the circadian BT rhythm and a shortening of sleep duration occur.
Collapse
Affiliation(s)
- D G Gubin
- a Department of Biology , Medical University , Tyumen , Russia.,b Tyumen Cardiology Research Center , Tomsk National Research Medical Center, Russian Academy of Science , Tomsk , Russia
| | - Т N Malishevskaya
- c Department of Organization of Medical Care , State Autonomous Health Care Institution Tyumen Regional Ophthalmological Dispensary , Tyumen , Russia.,d Department of Ophthalmology and Optometry , West-Siberian Institute of Postgraduate Medical Education , Tyumen , Russia
| | - Y S Astakhov
- e Department of Ophthalmology , Pavlov First Saint Petersburg State Medical University , St. Petersburg , Russia
| | - S Y Astakhov
- e Department of Ophthalmology , Pavlov First Saint Petersburg State Medical University , St. Petersburg , Russia
| | - G Cornelissen
- f Halberg Chronobiology Center , University of Minnesota , Minneapolis , MN , USA
| | - V A Kuznetsov
- b Tyumen Cardiology Research Center , Tomsk National Research Medical Center, Russian Academy of Science , Tomsk , Russia
| | - D Weinert
- g Institute of Biology/Zoology , Martin Luther University , Halle-Wittenberg , Germany
| |
Collapse
|
7
|
Marangoz D, Guzel E, Eyuboglu S, Gumusel A, Seckin I, Ciftci F, Yilmaz B, Yalvac I. Comparison of the neuroprotective effects of brimonidine tartrate and melatonin on retinal ganglion cells. Int Ophthalmol 2017; 38:2553-2562. [PMID: 29159432 DOI: 10.1007/s10792-017-0768-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Accepted: 11/12/2017] [Indexed: 02/07/2023]
Abstract
PURPOSE We aimed to compare the neuroprotective effects of brimonidine tartrate (BRT) and melatonin (MEL) on retinal ganglion cells (RGCs) in a rat glaucoma model. METHODS Thirty-six adult Wistar albino rats were allocated into six groups: control (C), glaucoma (G), BRT, MEL, G + BRT and G + MEL. After establishing the glaucoma model, intraocular pressure (IOP) of all animals measured at day 4 and day 30 was compared statistically with day 0 and day 4, respectively. Prior to sacrification at day 30 for histological evaluation and TUNEL analysis, retrograde labeling of non-apoptotic RGCs with 3% Fluorogold was performed and RGCs were evaluated under fluorescein microscope. RESULTS IOP measurements at day 4 were significantly higher than basal measurements in all glaucoma groups. BRT alone induced a time-dependent decrease in IOP (p < 0.05), while MEL alone failed to reduce IOP. However, both BRT and MEL reduced IOP in the presence of glaucoma at day 30 (p < 0.05). BRT treatment significantly reversed the reduced non-apoptotic RGC counts (p < 0.01) and increased TUNEL-positive RGCs (p < 0.001) to control group levels in the presence of glaucoma. However, no statistical significance was found between groups G and G + MEL considering 3% Fluorogold-labeled cell counts and apoptotic index values. CONCLUSION Our study revealed that systemic administration of BRT also has an IOP reducing effect. MEL has no neuroprotective effect on RGCs; on the other hand, BRT acts as a neuroprotective agent against glaucomatous injury, when applied systemically.
Collapse
Affiliation(s)
- Deniz Marangoz
- Department of Ophthalmology, Faculty of Medicine, Yeditepe University, Sakir Kesebir cad. Gazi Umur Pasa sok. No: 28, 34349, Beşiktaş-Istanbul, Turkey.
| | - Elif Guzel
- Department of Histology and Embryology, Cerrahpasa Faculty of Medicine, Istanbul University, Kocamustafapasa cad., 34098, Fatih-Istanbul, Turkey.
| | - Signem Eyuboglu
- Department of Physiology, Faculty of Medicine, Yeditepe University, Inonu mah. Kayisdagi cad. 26 Agustos Yerleskesi, 34755, Istanbul, Turkey
| | - Asli Gumusel
- Department of Histology and Embryology, Cerrahpasa Faculty of Medicine, Istanbul University, Kocamustafapasa cad., 34098, Fatih-Istanbul, Turkey
| | - Ismail Seckin
- Department of Histology and Embryology, Cerrahpasa Faculty of Medicine, Istanbul University, Kocamustafapasa cad., 34098, Fatih-Istanbul, Turkey
| | - Ferda Ciftci
- Department of Ophthalmology, Faculty of Medicine, Yeditepe University, Sakir Kesebir cad. Gazi Umur Pasa sok. No: 28, 34349, Beşiktaş-Istanbul, Turkey
| | - Bayram Yilmaz
- Department of Physiology, Faculty of Medicine, Yeditepe University, Inonu mah. Kayisdagi cad. 26 Agustos Yerleskesi, 34755, Istanbul, Turkey
| | - Ilgaz Yalvac
- Department of Ophthalmology, Faculty of Medicine, Yeditepe University, Sakir Kesebir cad. Gazi Umur Pasa sok. No: 28, 34349, Beşiktaş-Istanbul, Turkey
| |
Collapse
|
8
|
Crooke A, Huete-Toral F, Colligris B, Pintor J. The role and therapeutic potential of melatonin in age-related ocular diseases. J Pineal Res 2017; 63. [PMID: 28658514 DOI: 10.1111/jpi.12430] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 06/23/2017] [Indexed: 12/20/2022]
Abstract
The eye is continuously exposed to solar UV radiation and pollutants, making it prone to oxidative attacks. In fact, oxidative damage is a major cause of age-related ocular diseases including cataract, glaucoma, age-related macular degeneration, and diabetic retinopathy. As the nature of lens cells, trabecular meshwork cells, retinal ganglion cells, retinal pigment epithelial cells, and photoreceptors is postmitotic, autophagy plays a critical role in their cellular homeostasis. In age-related ocular diseases, this process is impaired, and thus, oxidative damage becomes irreversible. Other conditions such as low-grade chronic inflammation and angiogenesis also contribute to the development of retinal diseases (glaucoma, age-related macular degeneration and diabetic retinopathy). As melatonin is known to have remarkable qualities such as antioxidant/antinitridergic, mitochondrial protector, autophagy modulator, anti-inflammatory, and anti-angiogenic, it can represent a powerful tool to counteract all these diseases. The present review analyzes the role and therapeutic potential of melatonin in age-related ocular diseases, focusing on nitro-oxidative stress, autophagy, inflammation, and angiogenesis mechanisms.
Collapse
Affiliation(s)
- Almudena Crooke
- Department of Biochemistry and Molecular Biology IV, Group Ocupharm, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Fernando Huete-Toral
- Department of Biochemistry and Molecular Biology IV, Group Ocupharm, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Basilio Colligris
- Department of Biochemistry and Molecular Biology IV, Group Ocupharm, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Jesús Pintor
- Department of Biochemistry and Molecular Biology IV, Group Ocupharm, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| |
Collapse
|
9
|
Alkozi H, Sánchez-Naves J, de Lara MJP, Carracedo G, Fonseca B, Martinez-Aguila A, Pintor J. Elevated intraocular pressure increases melatonin levels in the aqueous humour. Acta Ophthalmol 2017; 95:e185-e189. [PMID: 27595784 DOI: 10.1111/aos.13253] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 07/31/2016] [Indexed: 12/27/2022]
Abstract
PURPOSE To study the levels of melatonin in the aqueous humour of normotensive and hypertensive intraocular pressure (IOP) patients and to compare them to an animal model of glaucoma. METHODS A total of 37 eyes of 37 patients who underwent cataract surgery were included in the study and were divided into normotensive patients, with IOP below 21 mmHg (n = 23), and hypertensive patients, with IOP > 21 mmHg (n = 14). Glaucomatous DBA/2J (n = 6) and control C57BL/6J (n = 6) mice presenting 3 and 12 months of age for each strain were also used. Human and mice aqueous humours were aspirated using a 30-gauge Rycroft cannula on a tuberculin syringe and further processed to quantify melatonin by high-performance liquid chromatography analysis. RESULTS Melatonin levels in normotensive patients (IOP below 21 mmHg) presented values as medians (first quartile; third quartile) of 14.62 (5.38;37.99) ng/ml (n = 23), while hypertensive patients (IOP above 21 mmHg) showed melatonin concentrations of 46.63 (10.28; 167.28) ng/ml (n = 14; p < 0.039). Glaucoma mice presented melatonin values of 0.37 (0.34; 0.59) ng/ml (at 3 months of age, before the pathology starts), which increased to 1.55 (0.94; 1.88) ng/ml (at 12 months of age, when the pathology is fully developed and IOP is maximum; n = 6, p < 0.001). Control mice did not significantly modified melatonin concentrations between 3 and 12 months of age. CONCLUSION Patients with high IOP present increased concentrations of melatonin in their aqueous humour compared to normotensive patients. This has been confirmed in a glaucomatous animal model in which it has been possible to see a correlation between the development of the pathology, with an increase in IOP, and a concomitant elevation of melatonin in the aqueous humour.
Collapse
Affiliation(s)
- Hanan Alkozi
- Department of Biochemistry and Molecular Biology IV; Faculty of Optics and Optometry; University Complutense of Madrid; Madrid Spain
| | - Juan Sánchez-Naves
- Department of Ophthalmology; Balear Institut of Ophthalmology; Palma de Mallorca Spain
| | - Maria Jesús Perez de Lara
- Department of Biochemistry and Molecular Biology IV; Faculty of Optics and Optometry; University Complutense of Madrid; Madrid Spain
| | - Gonzalo Carracedo
- Department of Optics II (Optometry and Vision); Faculty of Optics and Optometry; University Complutense of Madrid; Madrid Spain
| | - Begoña Fonseca
- Department of Biochemistry and Molecular Biology IV; Faculty of Optics and Optometry; University Complutense of Madrid; Madrid Spain
| | - Alejandro Martinez-Aguila
- Department of Biochemistry and Molecular Biology IV; Faculty of Optics and Optometry; University Complutense of Madrid; Madrid Spain
| | - Jesús Pintor
- Department of Biochemistry and Molecular Biology IV; Faculty of Optics and Optometry; University Complutense of Madrid; Madrid Spain
| |
Collapse
|
10
|
TRPV4 Stimulation Induced Melatonin Secretion by Increasing Arylalkymine N-acetyltransferase (AANAT) Protein Level. Int J Mol Sci 2017; 18:ijms18040746. [PMID: 28368307 PMCID: PMC5412331 DOI: 10.3390/ijms18040746] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Revised: 03/21/2017] [Accepted: 03/27/2017] [Indexed: 01/19/2023] Open
Abstract
Melatonin is a molecule which has gained a great deal of interest in many areas of science; its synthesis was classically known to be in the pineal gland. However, many organs synthesize melatonin, such as several ocular structures. Melatonin is known to participate in many functions apart from its main action regulating the circadian rhythm. It is synthesized from serotonin in two steps, with a rate-limiting step carried out by arylalkymine N-acetyltransferase (AANAT). In this report, the role of TRPV4 channel present in human ciliary body epithelial cells in AANAT production was studied. Several experiments were undertaken to verify the adequate time to reach the maximal effect by using the TRPV4 agonist GSK1016790A, together with a dose-response study. An increase of 2.4 folds in AANAT was seen after 18 h of incubation with 10 nM of GSK1016790A (p < 0.001, n = 6). This increment was verified by antagonist assays. In summary, AANAT levels and therefore melatonin synthesis change after TRPV4 channel stimulation. Using this cell model together with human ciliary body tissue it is possible to suggest that AANAT plays an important role in pathologies related to intraocular pressure.
Collapse
|
11
|
Alkozi HA, Wang X, Perez de Lara MJ, Pintor J. Presence of melanopsin in human crystalline lens epithelial cells and its role in melatonin synthesis. Exp Eye Res 2017; 154:168-176. [DOI: 10.1016/j.exer.2016.11.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Revised: 11/15/2016] [Accepted: 11/23/2016] [Indexed: 11/27/2022]
|
12
|
Aydin E, Sahin S. Increased melatonin levels in aqueous humor of patients with proliferative retinopathy in type 2 diabetes mellitus. Int J Ophthalmol 2016; 9:721-4. [PMID: 27275429 DOI: 10.18240/ijo.2016.05.15] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 10/13/2015] [Indexed: 11/23/2022] Open
Abstract
AIM To report the association between melatonin levels in aqueous humor and serum, and diabetic retinopathy (DR) grade in type 2 diabetic patients. METHODS Aqueous humor and plasma samples from 26 patients with DR (in nonproliferative and proliferative stages) and 14 control subjects were collected during cataract surgery after 6 p.m. Melatonin concentrations were determined using an enzyme-linked immunosorbent assay (ELISA). RESULTS Melatonin levels were significantly higher in the aqueous humor of patients with proliferative diabetic retinopathy (PDR) [18.57±2.67 pg/mL (range 15.20-23.06) vs 13.63±2.71 pg/mL (range 10.20-20.20), P=0.0001], but not in those with nonproliferative retinopathy (NPDR) [13.79±2.56 pg/mL (range 9.80-20.10) vs 13.63±2.71 pg/mL (range 10.20-20.20), P=0.961] compared to controls. There was decrement in the plasma melatonin level of patients with PDR, but no significant differences between the plasma melatonin levels of the study groups [5.37±1.74 pg/mL (range 2.85-8.65) vs 6.11±1.90 pg/mL (range 3.13-9.41), P=0.293], or between control and DR groups [NPDR 6.11±1.90 pg/mL (range 3.13-9.41) vs control 6.15±1.91 pg/mL (range 2.18-9.86); PDR (5.37±1.74 pg/mL (range 2.85-8.65) vs control 6.15±1.91 pg/mL (range 2.18-9.86), P=0.808, P=0.264]. CONCLUSION Elevated melatonin levels in aqueous humor in PDR may indicate the level to be associated with DR severity.
Collapse
Affiliation(s)
- Erdinc Aydin
- Izmir Katip Celebi University, Faculty of Medicine, Ophthalmology, Izmir 35620, Turkey
| | - Semsettin Sahin
- Gaziosmanpasa University Faculty of Medicine, Biochemistry, Tokat 60250, Turkey
| |
Collapse
|
13
|
TRPV4 activation triggers the release of melatonin from human non-pigmented ciliary epithelial cells. Exp Eye Res 2015; 136:34-7. [DOI: 10.1016/j.exer.2015.04.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 03/10/2015] [Accepted: 04/27/2015] [Indexed: 11/20/2022]
|
14
|
Abstract
Melatonin in the mammalian eye is synthesized by the photoreceptors and its levels show a clear daily pattern with high levels at night and lower levels during the day. It is synthesized in the ciliary body and secreted into the aqueous humor with a pattern similar to what has been reported for the retina. It acts by interacting with a family of G-protein coupled receptors that are negatively coupled with adenylate cyclase. Melatonin receptor subtypes MT1 and MT2 have been identified in the retina. Both are found in the inner nuclear layer (horizontal and amacrine cells), in the inner plexiform layer, ganglion cells (RGC) and retinal pigmented epithelium. They are also present in the ciliary body. Several studies implicate melatonin in the rhythmic regulation of intraocular pressure. MT1 and MT2 melatonin receptors are expressed in many parts of the eye. Melatonin receptors are expressed in the iris and ciliary body. Recent studies showed that mice lacking MT1 receptors have elevated intraocular pressure during the night and show a significantly reduced number of RGCs. These new studies suggest that dysfunctional melatonin signaling may be considered a possible risk factor in the pathogenesis of glaucoma and that mice deficient in MT1 receptors may be an animal model of glaucoma.
Collapse
|
15
|
Tabuchi H, Kiuchi Y, Nakakura S, Ohhara Z. Periodic analysis using two-way analysis of variance for the circadian rhythm of intraocular pressure in primary open angle glaucoma. BIOL RHYTHM RES 2012. [DOI: 10.1080/09291016.2011.599649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
16
|
Abstract
Oxidative stress has been proven to be related to the onset of a large number of health disorders. This chemical stress is triggered by an excess of free radicals, which are generated in cells because of a wide variety of exogenous and endogenous processes. Therefore, finding strategies for efficiently detoxifying free radicals has become a subject of a great interest, from both an academic and practical points of view. Melatonin is a ubiquitous and versatile molecule that exhibits most of the desirable characteristics of a good antioxidant. The amount of data gathered so far regarding the protective action of melatonin against oxidative stress is overwhelming. However, rather little is known concerning the chemical mechanisms involved in this activity. This review summarizes the current progress in understanding the physicochemical insights related to the free radical-scavenging activity of melatonin. Thus far, there is a general agreement that electron transfer and hydrogen transfer are the main mechanisms involved in the reactions of melatonin with free radicals. However, the relative importance of other mechanisms is also analyzed. The chemical nature of the reacting free radical also has an influence on the relative importance of the different mechanisms of these reactions. Therefore, this point has also been discussed in detail in the current review. Based on the available data, it is concluded that melatonin efficiently protects against oxidative stress by a variety of mechanisms. Moreover, it is proposed that even though it has been referred to as the chemical expression of darkness, perhaps it could also be referred to as the chemical light of health.
Collapse
Affiliation(s)
- Annia Galano
- Departamento de Química. Universidad Autónoma Metropolitana-Iztapalapa. Col. Vicentina. Iztapalapa. México D. F. México.
| | | | | |
Collapse
|
17
|
New treatments for ocular hypertension. Auton Neurosci 2009; 147:14-9. [PMID: 19176290 DOI: 10.1016/j.autneu.2008.12.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2008] [Revised: 12/18/2008] [Accepted: 12/22/2008] [Indexed: 12/15/2022]
Abstract
Glaucoma is a neurodegenerative pathology that affects the optic nerve producing blindness. This disease is often a consequence of an abnormal increase of intraocular pressure (IOP) due to a reduction in the ability of the eye to drain a transparent fluid termed aqueous humour. The dynamics of the aqueous humour is highly controlled by the autonomic nervous system, mainly the sympathetic, regulating its production and parasympathetic controlling the evacuation of aqueous humour. This has led pharmaceutical companies to develop chemicals which, by acting via different targets can substantially reduce IOP. Parasympathomimetics, adrenergic antagonists, plus eventually adrenergic agonists, are commonly used for the reduction of IOP and therefore for treatment of glaucoma. New substances linked to the nervous system that innervates the eye are emerging as interesting candidates. Nucleotides, commonly costored with catecholamines or acetylcholine or the indole melatonin, present interesting properties reducing IOP. Moreover new technological ideas such as the use of siRNA (small interference RNA) to silence protein expression demonstrate the relevance of this method to approach ocular hypertension and glaucoma from a different point of view. These three main groups of molecules: nucleotides, melatonins and siRNAs, are reviewed since they appear as firm candidates for the treatment of glaucoma in the near future.
Collapse
|
18
|
Mozaffarieh M, Grieshaber M, Orgül S, Flammer J. The Potential Value of Natural Antioxidative Treatment in Glaucoma. Surv Ophthalmol 2008; 53:479-505. [DOI: 10.1016/j.survophthal.2008.06.006] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
19
|
Alarma-Estrany P, Pintor J. Melatonin receptors in the eye: location, second messengers and role in ocular physiology. Pharmacol Ther 2006; 113:507-22. [PMID: 17229466 DOI: 10.1016/j.pharmthera.2006.11.003] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2006] [Accepted: 11/13/2006] [Indexed: 12/15/2022]
Abstract
The pineal hormone melatonin, an important regulator of circadian and seasonal rhythms, has a role in ocular pathophysiology. In addition to the pineal gland, melatonin synthesis is carried out in several ocular structures. Moreover, specific melatonin receptors have been located in the retina, cornea, ciliary body, lens, choroid and sclera, which suggests that cells in these tissues may be targets for melatonin action. This review summarizes the current knowledge about melatonin receptor subtypes with the emphasis on those melatonin receptors, which have been identified in ocular tissues and their possible roles in biochemical and physiological processes in the eye.
Collapse
Affiliation(s)
- Pilar Alarma-Estrany
- Departamento de Bioquímica, E.U. Optica, Universidad Complutense de Madrid, C/ Arcos de Jalón s/n, 28037 Madrid, Spain
| | | |
Collapse
|