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Zhang J, Zhou H, Cai Y, Yoshida S, Li Y, Zhou Y. Melatonin: Unveiling the functions and implications in ocular health. Pharmacol Res 2024; 205:107253. [PMID: 38862072 DOI: 10.1016/j.phrs.2024.107253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2024] [Revised: 06/06/2024] [Accepted: 06/07/2024] [Indexed: 06/13/2024]
Abstract
Melatonin, a versatile hormone produced by the pineal gland, has garnered considerable scientific interest due to its diverse functions. In the eye, melatonin regulates a variety of key processes like inhibiting angiogenesis by reducing vascular endothelial growth factor levels and protecting the blood-retinal barrier (BRB) integrity by enhancing tight junction proteins and pericyte coverage. Melatonin also maintains cell health by modulating autophagy via the Sirt1/mTOR pathways, reduces inflammation, promotes antioxidant enzyme activity, and regulates intraocular pressure fluctuations. Additionally, melatonin protects retinal ganglion cells by modulating aging and inflammatory pathways. Understanding melatonin's multifaceted functions in ocular health could expand the knowledge of ocular pathogenesis, and shed new light on therapeutic approaches in ocular diseases. In this review, we summarize the current evidence of ocular functions and therapeutic potential of melatonin and describe its roles in angiogenesis, BRB integrity maintenance, and modulation of various eye diseases, which leads to a conclusion that melatonin holds promising treatment potential for a wide range of ocular health conditions.
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Affiliation(s)
- Ji Zhang
- Department of Ophthalmology, The Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, China; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan 410011, China
| | - Haixiang Zhou
- Department of Ophthalmology, The Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, China; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan 410011, China
| | - Yuting Cai
- Department of Ophthalmology, The Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, China; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan 410011, China
| | - Shigeo Yoshida
- Department of Ophthalmology, Kurume University School of Medicine, Kurume, Fukuoka 830-0011, Japan
| | - Yun Li
- Department of Ophthalmology, The Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, China; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan 410011, China.
| | - Yedi Zhou
- Department of Ophthalmology, The Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, China; Hunan Clinical Research Center of Ophthalmic Disease, Changsha, Hunan 410011, China.
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Rusciano D, Russo C. The Therapeutic Trip of Melatonin Eye Drops: From the Ocular Surface to the Retina. Pharmaceuticals (Basel) 2024; 17:441. [PMID: 38675402 PMCID: PMC11054783 DOI: 10.3390/ph17040441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 03/18/2024] [Accepted: 03/27/2024] [Indexed: 04/28/2024] Open
Abstract
Melatonin is a ubiquitous molecule found in living organisms, ranging from bacteria to plants and mammals. It possesses various properties, partly due to its robust antioxidant nature and partly owed to its specific interaction with melatonin receptors present in almost all tissues. Melatonin regulates different physiological functions and contributes to the homeostasis of the entire organism. In the human eye, a small amount of melatonin is also present, produced by cells in the anterior segment and the posterior pole, including the retina. In the eye, melatonin may provide antioxidant protection along with regulating physiological functions of ocular tissues, including intraocular pressure (IOP). Therefore, it is conceivable that the exogenous topical administration of sufficiently high amounts of melatonin to the eye could be beneficial in several instances: for the treatment of eye pathologies like glaucoma, due to the IOP-lowering and neuroprotection effects of melatonin; for the prevention of other dysfunctions, such as dry eye and refractive defects (cataract and myopia) mainly due to its antioxidant properties; for diabetic retinopathy due to its metabolic influence and neuroprotective effects; for macular degeneration due to the antioxidant and neuroprotective properties; and for uveitis, mostly owing to anti-inflammatory and immunomodulatory properties. This paper reviews the scientific evidence supporting the use of melatonin in different ocular districts. Moreover, it provides data suggesting that the topical administration of melatonin as eye drops is a real possibility, utilizing nanotechnological formulations that could improve its solubility and permeation through the eye. This way, its distribution and concentration in different ocular tissues may support its pleiotropic therapeutic effects.
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Affiliation(s)
- Dario Rusciano
- Fidia Research Centre, c/o University of Catania, Via Santa Sofia 89, 95123 Catania, Italy
| | - Cristina Russo
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via Santa Sofia 89, 95123 Catania, Italy;
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Zhi X, Lu H, Ma D, Liu J, Luo L, Wang L, Qin Y. Melatonin protects photoreceptor cells against ferroptosis in dry AMD disorder by inhibiting GSK-3B/Fyn-dependent Nrf2 nuclear translocation. Biochim Biophys Acta Mol Basis Dis 2024; 1870:166969. [PMID: 38008231 DOI: 10.1016/j.bbadis.2023.166969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 11/02/2023] [Accepted: 11/20/2023] [Indexed: 11/28/2023]
Abstract
BACKGROUND Ferroptosis is a type of non-apoptotic cell death that relies on iron ions and reactive oxygen species to induce lipid peroxidation. This study aimed to determine whether ferroptosis exists in the pathogenesis of dry age-related macular degeneration (AMD) and to confirm that melatonin (MLT) suppresses the photoreceptor cell ferroptosis signaling pathway. METHODS We exposed 661W cells to sodium iodate (NaIO3) in vitro and treated them with different concentrations of MLT. In vivo, C57BL/6 mice were given a single caudal vein injection of NaIO3, followed by an intraperitoneal injection of MLT, and eyeballs were taken for subsequent trials. RESULTS We found that NaIO3 could induce photoreceptor cell death and lipid peroxide accumulation, and result in changes in the expression of ferroptosis-related factors and iron maintenance proteins, which were treated by MLT. We further demonstrated that MLT can block Fyn-dependent Nrf2 nuclear translocation by suppressing the GSK-3β signaling pathway. In addition, the therapeutic effect of MLT was significantly inhibited when Nrf2 was silenced. CONCLUSIONS Our findings provide a novel insight that NaIO3 induces photoreceptor cell ferroptosis in dry AMD and suggest that MLT has therapeutic effects by suppressing GSK-3β/Fyn-dependent Nrf2 nuclear translocation.
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Affiliation(s)
- Xinyu Zhi
- Department of Ophthalmology, the Fourth Affiliated Hospital of China Medical University, Eye Hospital of China Medical University, Key Lens Research Laboratory of Liaoning Province, Shenyang City, Liaoning Province, 110005, PR China
| | - Haojie Lu
- Cooperation of Chinese and Western medicine branch, Jiangsu Rongjun Hospital, Wuxi, Jiangsu, PR China
| | - Dongyue Ma
- Department of Ophthalmology, the Fourth Affiliated Hospital of China Medical University, Eye Hospital of China Medical University, Key Lens Research Laboratory of Liaoning Province, Shenyang City, Liaoning Province, 110005, PR China
| | - Jinxia Liu
- Department of Ophthalmology, the Fourth Affiliated Hospital of China Medical University, Eye Hospital of China Medical University, Key Lens Research Laboratory of Liaoning Province, Shenyang City, Liaoning Province, 110005, PR China
| | - Li Luo
- Department of Ophthalmology, the Fourth Affiliated Hospital of China Medical University, Eye Hospital of China Medical University, Key Lens Research Laboratory of Liaoning Province, Shenyang City, Liaoning Province, 110005, PR China
| | - Ludi Wang
- Department of Ophthalmology, the Fourth Affiliated Hospital of China Medical University, Eye Hospital of China Medical University, Key Lens Research Laboratory of Liaoning Province, Shenyang City, Liaoning Province, 110005, PR China
| | - Yu Qin
- Department of Ophthalmology, the Fourth Affiliated Hospital of China Medical University, Eye Hospital of China Medical University, Key Lens Research Laboratory of Liaoning Province, Shenyang City, Liaoning Province, 110005, PR China.
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Sane S, Motarjemizadeh Q, Komilzhonovich IN, Abdelbasset WK, Zaman GS, Suksatan W, Morwati S, Haki BK, Rahmani N, Golabi P, Mahmodi H. The Effect of Melatonin on Analgesia, Anxiety, and Intraocular Pressure (IOP) in Cataract Surgery Under Topical Anesthesia. J Perianesth Nurs 2023; 38:253-257. [PMID: 36323602 DOI: 10.1016/j.jopan.2022.05.081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 05/01/2022] [Accepted: 05/25/2022] [Indexed: 03/27/2023]
Abstract
PURPOSE This study investigated the effect of oral melatonin as a premedication before cataract surgery on pain score, anxiety, surgical conditions, and intraocular pressure (IOP) during cataract surgery with phacoemulsification under topical anesthesia. DESIGN This randomized, double-blind prospective study was conducted among 120 patients aged 50 to 80. METHODS Patients were randomly assigned to receive either sublingual melatonin 3 mg or placebo 60 min before surgery. Verbal anxiety and pain scores, heart rate, systolic and diastolic blood pressure, intraocular pressure, and quality of surgical conditions were recorded. The results were analyzed using SPSS 23 software, and statistical analysis consisted of χ2 test and t-test, and a P value less than .05 was considered significant. FINDINGS There was a significant difference between the two groups regarding pain after the surgery before being discharged from the recovery room. The mean pain score in the melatonin group was lower than the placebo group in T4 (in the postoperative ward) (P < .05). The anxiety score of patients was lower in the melatonin group in T3 and T4 (during surgery and in the postoperative ward, respectively) (P < .05). IOP was significantly lower in the case group at the end of the surgery after receiving premedication (P = .021). CONCLUSIONS This study showed that 3 mg Sublingual melatonin premedication for patients undergoing cataract surgery under topical anesthesia reduced patients' anxiety scores, pain score, and IOP.
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Affiliation(s)
- Shahryar Sane
- Department of Anesthesiology, Urmia Imam Khomeini Hospital, Urmia University of Medical Science, Urmia, Iran
| | - Qader Motarjemizadeh
- Department of Ophthalmology, Urmia Imam Khomeini Hospital, Urmia University of Medical Science, Urmia, Iran
| | | | - Walid Kamal Abdelbasset
- Department of Health and Rehabilitation Sciences, College of Applied Medical Sciences, Prince Sattam bin Abdulaziz University, Al Kharj, Saudi Arabia
| | - Gaffar Sarwar Zaman
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Khalid University, Abha, Saudi Arabia
| | - Wanich Suksatan
- Faculty of Nursing, HRH Princess Chulabhorn College of Medical Science, Chulabhorn Royal Academy, Bangkok, Thailand
| | - Shabnam Morwati
- Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Behzad Kazemi Haki
- Department of Anesthesiology, Urmia Imam Khomeini Hospital, Urmia University of Medical Science, Urmia, Iran
| | - Nazila Rahmani
- College of Medical, Veterinary & Life Science, University of Glasgow, Glasgow, United Kingdom
| | - Parang Golabi
- Department of Anesthesiology, Omid Charity Hospital, Urmia University of Medical Science, Urmia, Iran.
| | - Hamed Mahmodi
- Department of Medicine, Urmia University of Medical Science, Urmia, Iran
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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.
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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
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Chauhan S, Norbury R, Faßbender KC, Ettinger U, Kumari V. Beyond sleep: A multidimensional model of chronotype. Neurosci Biobehav Rev 2023; 148:105114. [PMID: 36868368 DOI: 10.1016/j.neubiorev.2023.105114] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 02/09/2023] [Accepted: 02/27/2023] [Indexed: 03/05/2023]
Abstract
Chronotype can be defined as an expression or proxy for circadian rhythms of varied mechanisms, for example in body temperature, cortisol secretion, cognitive functions, eating and sleeping patterns. It is influenced by a range of internal (e.g., genetics) and external factors (e.g., light exposure), and has implications for health and well-being. Here, we present a critical review and synthesis of existing models of chronotype. Our observations reveal that most existing models and, as a consequence, associated measures of chronotype have focused solely or primarily on the sleep dimension, and typically have not incorporated social and environmental influences on chronotype. We propose a multidimensional model of chronotype, integrating individual (biological and psychological), environmental and social factors that appear to interact to determine an individual's true chronotype with potential feedback loops between these factors. This model could be beneficial not only from a basic science perspective but also in the context of understanding health and clinical implications of certain chronotypes as well as designing preventive and therapeutic approaches for related illnesses.
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Affiliation(s)
- Satyam Chauhan
- Department of Psychology, College of Health, Medicine and Life Sciences, Brunel University London, London, United Kingdom; Centre for Cognitive and Clinical Neuroscience, College of Health, Medicine and Life Sciences, Brunel University London, London, United Kingdom.
| | - Ray Norbury
- Department of Psychology, College of Health, Medicine and Life Sciences, Brunel University London, London, United Kingdom; Centre for Cognitive and Clinical Neuroscience, College of Health, Medicine and Life Sciences, Brunel University London, London, United Kingdom
| | | | | | - Veena Kumari
- Department of Psychology, College of Health, Medicine and Life Sciences, Brunel University London, London, United Kingdom; Centre for Cognitive and Clinical Neuroscience, College of Health, Medicine and Life Sciences, Brunel University London, London, United Kingdom.
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Nemr AA, El-Mahrouk GM, Badie HA. Hyaluronic acid-enriched bilosomes: an approach to enhance ocular delivery of agomelatine via D-optimal design: formulation, in vitro characterization, and in vivo pharmacodynamic evaluation in rabbits. Drug Deliv 2022; 29:2343-2356. [PMID: 35869684 PMCID: PMC9477486 DOI: 10.1080/10717544.2022.2100513] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Agomelatine (AGO) is a dual-functional drug. It uses as an antidepressant when orally administrated and antiglaucomic when topically applied to the eye. This study aimed to formulate AGO into bilosomal vesicles for glaucoma treatment, as modern studies pointed out the effect of topical AGO on intraocular pressure for the treatment of glaucoma. A modified ethanol injection technique was used for the fabrication of AGO bilosomes according to a D-optimal design. Phosphatidylcholine (PC) to edge activator (EA) ratio, Hyaluronic acid percentage (HA%), and EA type were utilized as independent variables. The measured responses were percent entrapment efficiency (EE%), particle size (PS), polydispersity index, zeta potential, percentage of drug released after 2 h (Q2h%), and 24 h (Q24h%). The optimal bilosomal formula (OB), with the desirability of 0.814 and the composition of 2:1 PC: EA ratio, 0.26% w/v HA and sodium cholate as EA, was subjected to further in vitro characterizations and in vivo evaluation studies. The OB formula had EE% of 81.81 ± 0.23%, PS of 432.45 ± 0.85 nm, Q2h% of 42.65 ± 0.52%, and Q24h% of 75.14 ± 0.39%. It demonstrated a higher elasticity than their corresponding niosomes with a typical spherical shape of niosomes by using transmission electron microscope. It exhibited acceptable stability over three months. pH and Refractive index measurements together with the histopathological study ensured that the OB formula is safe for the eye and causes no ocular irritation or blurred vision. The OB formula showed superiority in the in vivo pharmacodynamics parameters over the AGO solution, so AGO-loaded bilosome could improve ocular delivery and the bioavailability of agomelatine.
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Affiliation(s)
- Asmaa Ashraf Nemr
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Cairo University, Egypt
| | - Galal Mohamed El-Mahrouk
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Cairo University, Egypt
| | - Hany Abdo Badie
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Cairo University, Egypt
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Usta Sofu G, Erzurumlu Y, Karaca U, Candan IA, Savran M, Asci H, Hasseyid N. Melatonin receptor agonist ramelteon alleviates experimental acute ocular inflammation via HIF-1Α/VEGF/E-NOS signaling. Eur J Ophthalmol 2022; 33:11206721221123878. [PMID: 36062605 DOI: 10.1177/11206721221123878] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Ramelteon (RML) is a potent, selective agonist of the high-affinity melatonin receptor 1 and 2 receptors. In addition, RML is known to have antioxidant and anti-inflammatory effects. In this study, we aimed to investigate the effects of RML on HIF-1α, VEGF and e-NOS signaling pathway in a rat model of endotoxin-induced uveitis (EIU). METHODS Twenty-eight Wistar albino rats were divided into 4 groups as controls, lypopolysaccharide (LPS) group (5 mg/kg i.p.), LPS + RML group (5 mg/kg i.p and 8 mg/kg orally, respectively) and RML group (8 mg/kg orally). EIU was induced by a single intraperitoneal LPS injection. Histopathological and genetical analyses were performed. RESULTS In histopathological analysis, LPS caused mild anterior uveitis characterized by increased surface area of iris leaflets and ciliary body due to edema, mild to moderate congestion, and inflammatory infiltrate 6 h following the injection. The pathological findings were reduced by RML. Higher inflammation levels seen in LPS group were significantly reduced in LPS + RML group. Also, HIF-1 α, eNOS and VEGF expressions increased in LPS and decreased in LPS + RML group. CONCLUSION RML treatment reversed the changes in the HIF-1α /eNOS/ VEGF signaling pathway in LPS-induced uveitis in rats, preventing the progression of the damage and showed positive effects.
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Affiliation(s)
- Gulsah Usta Sofu
- Department of Ophthalmology, Faculty of Medicine, 52994Suleyman Demirel University, Isparta, Turkey
| | - Yalcın Erzurumlu
- Department of Biochemistry, Faculty of Pharmacy, 52994Suleyman Demirel University, Isparta, Turkey
| | - Umut Karaca
- Department of Ophthalmology, Faculty of Medicine, 52994Suleyman Demirel University, Isparta, Turkey
| | - Ibrahim Aydın Candan
- Department of Histology and Embryology, Faculty of Medicine, 450199Alaaddin Keykubat University, Alanya, Turkey
| | - Mehtap Savran
- Department of Pharmacology, Faculty of Medicine, 52994Suleyman Demirel University, Isparta, Turkey
| | - Halil Asci
- Department of Pharmacology, Faculty of Medicine, 52994Suleyman Demirel University, Isparta, Turkey
| | - Nursel Hasseyid
- Department of Pharmacology, Faculty of Medicine, 52994Suleyman Demirel University, Isparta, Turkey
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Bargues-Navarro G, Ibáñez-del Valle V, El Mlili N, Cauli O. Salivary Biomarkers Associated with Psychological Alterations in Patients with Diabetes: A Systematic Review. MEDICINA (KAUNAS, LITHUANIA) 2022; 58:medicina58081091. [PMID: 36013558 PMCID: PMC9416232 DOI: 10.3390/medicina58081091] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 07/26/2022] [Accepted: 08/09/2022] [Indexed: 11/16/2022]
Abstract
The care of individuals with diabetes needs a holistic perspective, taking into account both the physical disease and the mental health problems that may be associated. Different studies show a higher prevalence of depression or anxiety issues in diabetes patients than in the general population, which is why diabetes can be considered one of the chronic diseases in which psychological care is crucial to maintain quality of life. The objective of this review is to examine the published articles that relate the bidirectional associations between objective and subjective measures of anxiety, depressive symptomatology, stress, sleep quality, and salivary biomarkers in patients with diabetes. For this, a search was carried out in the electronic databases PubMed, Cochrane, and SCOPUS using the keywords "diabetes", "saliva", "sleep", "anxiety", "depression", and "stress" for works published up until May 2022 and limited to the English and Spanish languages. The sample comprised 14 articles, 5 of which analysed the associations between depressive symptomatology and salivary biomarkers in people with diabetes. Among the salivary biomarkers most frequently used to evaluate psychological alterations in persons with diabetes are cortisol and melatonin. Thus, significant changes in the levels of these biomarkers were observed in most studies. Four out of five studies reported a statistically significant relationship between increased salivary cortisol in the evening/midnight or the cortisol awakening response and depressive symptoms. In contrast, lower cortisol levels upon waking in the morning were observed when there was no depression or anxiety. Regarding the association between salivary cortisol values and sleep quality in patients with diabetes, lower morning cortisol values related to prolonged nighttime sleep were common in the analysed studies. Low melatonin concentrations showed a negative correlation with sleep quality. As it is an easy-to-apply and non-invasive method, the measurement of salivary biomarkers can be very useful for predicting psychological alterations in patients with diabetes. Further scientific studies are required to determine the sensitivity of these biological substances acting as biomarkers for detecting sleep disorders and psychological alterations.
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Affiliation(s)
- Guillermo Bargues-Navarro
- Department of Nursing, Faculty of Nursing and Podiatry, University of Valencia, Avda Menéndez Pidal 19, 46010 Valencia, Spain
| | - Vanessa Ibáñez-del Valle
- Department of Nursing, Faculty of Nursing and Podiatry, University of Valencia, Avda Menéndez Pidal 19, 46010 Valencia, Spain
- Frailty and Cognitive Impairment Organized Group (FROG), University of Valencia, 46010 Valencia, Spain
- Chair of Active Ageing, University of Valencia, 4610 Valencia, Spain
| | - Nisrin El Mlili
- Higher Institute of Nursing Professions and Health Techniques (ISPITS), Tetouan 93000, Morocco
- Department of Biology and Health, Faculty of Sciences, University Abdelmalek Essâadi, Tetouan 93000, Morocco
| | - Omar Cauli
- Department of Nursing, Faculty of Nursing and Podiatry, University of Valencia, Avda Menéndez Pidal 19, 46010 Valencia, Spain
- Frailty and Cognitive Impairment Organized Group (FROG), University of Valencia, 46010 Valencia, Spain
- Chair of Active Ageing, University of Valencia, 4610 Valencia, Spain
- Correspondence:
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Yu S, Cui K, Wu P, Wu B, Lu X, Huang R, Tang X, Lin J, Yang B, Zhao J, He Q, Liang X, Xu Y. Melatonin prevents experimental central serous chorioretinopathy in rats. J Pineal Res 2022; 73:e12802. [PMID: 35436360 DOI: 10.1111/jpi.12802] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 04/08/2022] [Accepted: 04/12/2022] [Indexed: 11/28/2022]
Abstract
Central serous chorioretinopathy (CSC) is a vision-threatening disease with no validated treatment and unclear pathogenesis. It is characterized by dilation and leakage of choroidal vasculature, resulting in the accumulation of subretinal fluid, and serous detachment of the neurosensory retina. Numerous studies have demonstrated that melatonin had multiple protective effects against endothelial dysfunction, vascular inflammation, and blood-retinal barrier (BRB) breakdown. However, the effect of melatonin on CSC, and its exact pathogenesis, is not well understood thus far. In this study, an experimental model was established by intravitreal injection of aldosterone in rats, which mimicked the features of CSC. Our results found that melatonin administration in advance significantly inhibited aldosterone-induced choroidal thickening and vasodilation by reducing the expression of calcium-activated potassium channel KCa2.3, and attenuated tortuosity of choroid vessels. Moreover, melatonin protected the BRB integrity and prevented the decrease in tight junction protein (ZO-1, occludin, and claudin-1) levels in the rat model induced by aldosterone. Additionally, the data also showed that intraperitoneal injection of melatonin in advance inhibited aldosterone-induced macrophage/microglia infiltration, and remarkably diminished the levels of inflammatory cytokines (interleukin-6 [IL-6], IL-1β, and cyclooxygenase-2), chemokines (chemokine C-C motif ligand 3, and C-X-C motif ligand 1), and matrix metalloproteinases (MMP-2 and MMP-9). Luzindole, as the nonselective MT1 and MT2 antagonist, and 4-phenyl-2-propionamidotetraline, as the selective MT2 antagonist, neutralized the melatonin-induced inhibition of choroidal thickening and choroidal vasodilation, indicating that melatonin might exert the effects via binding to its receptors. Furthermore, the IL-17A/nuclear factor-κB signaling pathway was activated by intravitreal administration of aldosterone, while it was suppressed in melatonin-treated in advance rat eyes. This study indicates that melatonin could serve as a promising safe therapeutic strategy for CSC patients.
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Affiliation(s)
- Shanshan Yu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Kaixuan Cui
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Peiqi Wu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Benjuan Wu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Xi Lu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Rong Huang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Xiaoyu Tang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Jianqiang Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Boyu Yang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Jinfeng Zhao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Qingjing He
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Xiaoling Liang
- 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
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11
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Navarro-Gil FJ, Huete-Toral F, Domínguez-Godínez CO, Carracedo G, Crooke A. Contact Lenses Loaded with Melatonin Analogs: A Promising Therapeutic Tool against Dry Eye Disease. J Clin Med 2022; 11:jcm11123483. [PMID: 35743553 PMCID: PMC9225312 DOI: 10.3390/jcm11123483] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 06/11/2022] [Accepted: 06/14/2022] [Indexed: 12/21/2022] Open
Abstract
Melatonin analogs topically administered evoke a potent tear secretagogue effect in rabbits. This route of drug administration requires high drug concentration and frequent dosing due to its reduced ocular surface retention. Therefore, contact lenses (CLs) have emerged as an alternative drug-delivery system that prolongs drug retention in the cornea, improving its therapeutic performance. This study explores the in vitro ability of five commercially available hydrogel CLs to act as a delivery system for melatonin analogs and the in vivo secretagogue effect of melatonin analog-loaded CLs. We soaked CLs with melatonin or melatonin analog solutions (1 mM) for 12 h. Spectroscopic assays showed that IIK7-loaded CLs led to the inadequate delivery of this compound. Conventional hydrogel lenses loaded with agomelatine released more agomelatine than silicone ones (16–33% more). In contrast, the CLs of silicone materials are more effective as a delivery system of 5-MCA-NAT than CLs of conventional materials (24–29%). The adaptation of CLs loaded with agomelatine or 5-MCA-NAT in rabbits triggered a higher tear secretion than the corresponding eye drops (78% and 59% more, respectively). These data suggest that CLs preloaded with melatonin analogs could be an adequate strategy to combat aqueous tear deficient dry eye disease.
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Affiliation(s)
- Francisco Javier Navarro-Gil
- Department of Optometry and Vision, Faculty of Optics and Optometry, Complutense University of Madrid, 28037 Madrid, Spain; (C.O.D.-G.); (G.C.)
- Correspondence: (F.J.N.-G.); (A.C.); Tel.: +34-91-3946883 (F.J.N.-G); +34-91-3946859 (A.C.)
| | - Fernando Huete-Toral
- Department of Biochemistry and Molecular Biology, Faculty of Optics and Optometry, Complutense University of Madrid, 28037 Madrid, Spain;
| | - Carmen Olalla Domínguez-Godínez
- Department of Optometry and Vision, Faculty of Optics and Optometry, Complutense University of Madrid, 28037 Madrid, Spain; (C.O.D.-G.); (G.C.)
| | - Gonzalo Carracedo
- Department of Optometry and Vision, Faculty of Optics and Optometry, Complutense University of Madrid, 28037 Madrid, Spain; (C.O.D.-G.); (G.C.)
| | - Almudena Crooke
- Department of Biochemistry and Molecular Biology, Faculty of Optics and Optometry, Complutense University of Madrid, 28037 Madrid, Spain;
- Correspondence: (F.J.N.-G.); (A.C.); Tel.: +34-91-3946883 (F.J.N.-G); +34-91-3946859 (A.C.)
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12
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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.
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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
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13
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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,
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14
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Shen S, Li X, Li R, Huang D, Zhao X, Zhang X, Hao Q, Sun Q, Tong H, Zheng X, Cao Y, Liu S, Zhu H, Liu H. Association of sleep disorders with subfoveal choroidal thickness in preschool children. Eye (Lond) 2021; 36:448-456. [PMID: 33707765 PMCID: PMC8807704 DOI: 10.1038/s41433-021-01489-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 01/29/2021] [Accepted: 02/22/2021] [Indexed: 12/24/2022] Open
Abstract
OBJECTIVE To explore the association between sleep disorders and subfoveal choroidal thickness (SFCT) in preschool children. METHODS In this population-based cross-sectional study, children aged 60-72 months were measured for SFCT using spectral-domain optical coherence tomography (SD-OCT) and for sleep disorders using the Chinese version of Children's Sleep Habits Questionnaire (CSHQ). Multiple linear regression analyses were performed to assess the association between sleep disorders and SFCT. RESULTS A total of 1337 children (mean (SD) age: 66.88 (3.41) months) were included in the analyses. In multivariable linear analysis, a higher total CSHQ score (indicating higher likelihood of sleep disorders) was associated with a thinner subfoveal choroid (beta, -0.070; 95% CI, -0.141 to -0.001; P = 0.046). When each of eight CSHQ subscale scores was analysed by the multivariable model, only the Daytime Sleepiness subscale score was negatively associated with the SFCT (beta, -0.115; 95% CI, -0.183 to -0.046; P = 0.001). The children with clinically significant daytime sleepiness (n = 364, 27.2%) had significantly thinner subfoveal choroid than other children (295.47 vs. 308.52 μm, P = 0.007). CONCLUSIONS Only daytime sleepiness was significantly associated with SFCT in preschool children in this study. The potential relationship between sleep disorders during childhood and children's ocular development needs further research.
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Affiliation(s)
- Shiya Shen
- Department of Ophthalmology, The First Affiliated Hospital with Nanjing Medical University, Nanjing, China
| | - Xiaoxiao Li
- Department of Ophthalmology, The First Affiliated Hospital with Nanjing Medical University, Nanjing, China
| | - Rui Li
- Department of Ophthalmology, The First Affiliated Hospital with Nanjing Medical University, Nanjing, China
| | - Dan Huang
- Department of Child Healthcare, The First Affiliated Hospital with Nanjing Medical University, Nanjing, China
| | - Xiaoyan Zhao
- Department of Ophthalmology, The First Affiliated Hospital with Nanjing Medical University, Nanjing, China
| | - Xiaohan Zhang
- Department of Ophthalmology, Wuxi Children's Hospital, Wuxi, China
| | - Qingfeng Hao
- Department of Ophthalmology, The First Affiliated Hospital with Nanjing Medical University, Nanjing, China
| | - Qigang Sun
- Department of Ophthalmology, Maternal and Child Healthcare Hospital of Yuhuatai District, Nanjing, China
| | - Haohai Tong
- Department of Ophthalmology, The First Affiliated Hospital with Nanjing Medical University, Nanjing, China
| | - Xinyu Zheng
- The Fourth School of Clinical Medicine of Nanjing Medical University, Nanjing, China
| | - Yelongzi Cao
- The Fourth School of Clinical Medicine of Nanjing Medical University, Nanjing, China
| | - Shuning Liu
- The Fourth School of Clinical Medicine of Nanjing Medical University, Nanjing, China
| | - Hui Zhu
- Department of Ophthalmology, The First Affiliated Hospital with Nanjing Medical University, Nanjing, China.
| | - Hu Liu
- Department of Ophthalmology, The First Affiliated Hospital with Nanjing Medical University, Nanjing, China.
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15
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Nishimon S, Nishino N, Nishino S. Advances in the pharmacological management of non-24-h sleep-wake disorder. Expert Opin Pharmacother 2021; 22:1039-1049. [PMID: 33618599 DOI: 10.1080/14656566.2021.1876665] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Introduction: Melatonin, a hormone that regulates circadian rhythms and the sleep-wake cycle, is produced mainly during the dark period in the pineal gland and is suppressed by light exposure. Patients with non-24-h sleep-wake disorder (non-24) fail to entrain the master clock with the 24-h light-dark cycle due to the lack of light perception to the suprachiasmatic nucleus typically in totally blind individuals or other organic disorders in sighted individuals, causing a progressive delay in the sleep-wake cycle and periodic insomnia and daytime sleepiness.Areas covered: Herein, the authors review the pharmacological therapies including exogenous melatonin and melatonin receptor agonists for the management of non-24. They introduce a historical report about the effects of melatonin on the phase shift and entrainment for blind individuals with the free-running circadian rhythm.Expert opinion: Orally administered melatonin entrains the endogenous circadian rhythm and improves nighttime sleep and daytime alertness for non-24. Currently, tasimelteon is the only approved medication for non-24 by the US Food and Drug Administration and the European Medicines Agency. Treatments that focus only on sleep problems are insufficient for the treatment of non-24, and aids to entrain the free-running rhythm with the light-dark cycle are needed.
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Affiliation(s)
- Shohei Nishimon
- Sleep and Circadian Neurobiology Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, USA.,Department of Psychiatry and Behavioral Science, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Naoya Nishino
- Sleep and Circadian Neurobiology Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, USA
| | - Seiji Nishino
- Sleep and Circadian Neurobiology Laboratory, Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Palo Alto, USA
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16
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Mehrzadi S, Hemati K, Reiter RJ, Hosseinzadeh A. Mitochondrial dysfunction in age-related macular degeneration: melatonin as a potential treatment. Expert Opin Ther Targets 2020; 24:359-378. [PMID: 32116056 DOI: 10.1080/14728222.2020.1737015] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Introduction: Age-related Macular Degeneration (AMD), a retinal neurodegenerative disease is the most common cause of blindness among the elderly in developed countries. The impairment of mitochondrial biogenesis has been reported in human retinal pigment epithelium (RPE) cells affected by AMD. Oxidative/nitrosative stress plays an important role in AMD development. The mitochondrial respiratory system is considered a major site of reactive oxygen species (ROS) generation. During aging, insufficient free radical scavenger systems, impairment of DNA repair mechanisms and reduction of mitochondrial degradation and turnover contribute to the massive accumulation of ROS disrupting mitochondrial function. Impaired mitochondrial function leads to the decline in the autophagic capacity and induction of inflammation and apoptosis in human RPE cells affected by AMD.Areas covered: This article evaluates the ameliorative effect of melatonin on AMD and examines AMD pathogenesis with an emphasis on mitochondrial dysfunction. It also considers the potential effects of melatonin on mitochondrial function.Expert opinion: The effect of melatonin on mitochondrial function results in the reduction of oxidative stress, inflammation and apoptosis in the retina; these findings demonstrate that melatonin has the potential to prevent and treat AMD.
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Affiliation(s)
- Saeed Mehrzadi
- Razi Drug Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Karim Hemati
- Department of Anesthesiology, Iran University of Medical Sciences, Tehran, Iran
| | - Russel J Reiter
- Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Azam Hosseinzadeh
- Razi Drug Research Center, Iran University of Medical Sciences, Tehran, Iran
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17
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Abbasivash R, Salimi S, Ahsan B, Moallemi N, Sane S. The Effect of Melatonin on Anxiety and Pain of Tourniquet in Intravenous Regional Anesthesia. Adv Biomed Res 2019; 8:67. [PMID: 31897405 PMCID: PMC6909545 DOI: 10.4103/abr.abr_106_19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 10/09/2019] [Accepted: 10/12/2019] [Indexed: 01/01/2023] Open
Abstract
Background: Melatonin has anxiolytic and potential analgesic effects. Several studies have indicated the sedative and anti-anxiety effects of melatonin when used as premedication before surgery. Hence, we assessed the efficacy of melatonin premedication in tourniquet-related pain and analgesia in patients receiving intravenous regional anesthesia (IVRA). Materials and Methods: Fifty patients undergoing elective hand surgery under IVRA were randomly divided into two groups (25 patients each) to receive either melatonin 6 mg (melatonin group) or placebo (control group) as oral premedication. IVRA was achieved with lidocaine, 3 mg/kg, diluted with saline to a total volume of 40 mL. Anxiety scores, sensory and motor block onset and recovery times, tourniquet pain, and 24-h analgesic requirements were recorded. Results: The onset of motor and sensory block was statistically significantly shorter in Group M (P < 0.001), and recovery of motor and sensory block was statistically significantly longer in Group M (P < 0.001). The time of starting tourniquet pain was longer in Group M (P < 0.001). The mean anxiety score in the study group was 3 ± 0.81 and in the control group was 4.20 ± 1.04 (P = 0.001). There was a statistically significant difference in the need for opioids between the two groups (P < 0.05). Conclusions: Melatonin is an effective premedication before IVRA because it reduces patient anxiety, decreases tourniquet-related pain, and improves perioperative analgesia.
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Affiliation(s)
- Rahman Abbasivash
- Department of Anesthesiology, Imam Khomeini Hospital, Urmia University of Medical Sciences, Urmia, Iran
| | - Sohrab Salimi
- Department of Anesthesiology, School of Medicine, Imam Hossein Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Behzad Ahsan
- Department of Anesthesiology, Kurdistan University of Medical Sciences, Sanandaj, Iran
| | - Neda Moallemi
- Department of Anesthesiology, Imam Khomeini Hospital, Urmia University of Medical Sciences, Urmia, Iran
| | - Shahryar Sane
- Department of Anesthesiology, Imam Khomeini Hospital, Urmia University of Medical Sciences, Urmia, Iran
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18
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Carracedo-Rodríguez G, Martínez-Águila A, Rodriguez-Pomar C, Bodas-Romero J, Sanchez-Naves J, Pintor J. Effect of nutritional supplement based on melatonin on the intraocular pressure in normotensive subjects. Int Ophthalmol 2019; 40:419-422. [PMID: 31650354 DOI: 10.1007/s10792-019-01199-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Accepted: 10/19/2019] [Indexed: 01/10/2023]
Abstract
PURPOSE To evaluate the effect of a new nutritional supplement based on melatonin on the intraocular pressure (IOP) in normotensive subjects. PATIENTS AND METHODS A short-term prospective study was designed. Sixty-seven normotensive subjects were recruited. Patients were divided into two groups. The daily group (DG) (n = 18) was instructed to take the supplement between 22:00 and 23:00 (before sleeping) for 3 consecutive days. IOP was measured from 10.00 to 11.00 am the day before treatment and during the 3 days of experiment. The acute group (AG) (n = 49) was instructed to take the supplement after the second measure (11.00) of the second day. IOP was measured 1 h and just before the intake of the supplement and 1 and 2 h after. All measurements in this group were taken 1 day before without any supplement (control) and the day of experiment. RESULTS The DG group showed a significant decrease in IOP after supplement intake in all days of experiment, from 14.9 ± 3.4 mm Hg to 13.8 ± 2.9 mm Hg after 3 days of experiment (p value < 0.001). For AG, IOP did not change during the control day; however, a reduction of 1 mm Hg was found 2 and 3 h after supplement intake, from 15.7 ± 2.5 mm Hg to 14.7 ± 2.5 mm Hg and 15.1 ± 2.7 mm Hg, respectively, being statistically significant (p value < 0.001). CONCLUSION The supplement based on melatonin was able to reduce the IOP in normotensive subjects after 2 h of intake. Moreover, the daily intake showed a reduction in IOP during the 3 days of experiment.
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Affiliation(s)
- Gonzalo Carracedo-Rodríguez
- Ocupharm Diagnostics Group Research, Faculty of Optic and Optometry, Department of Optometry and Vision, University Complutense of Madrid, C/Arcos del Jalon 118, 28032, Madrid, Spain.
| | | | | | - Julia Bodas-Romero
- Ocupharm Diagnostics Group Research, Faculty of Optic and Optometry, Department of Optometry and Vision, University Complutense of Madrid, C/Arcos del Jalon 118, 28032, Madrid, Spain
| | - Juan Sanchez-Naves
- Ocupharm Diagnostics Group Research, Faculty of Optic and Optometry, Department of Optometry and Vision, University Complutense of Madrid, C/Arcos del Jalon 118, 28032, Madrid, Spain
| | - Jesús Pintor
- Ocupharm Diagnostics Group Research, Faculty of Optic and Optometry, Department of Optometry and Vision, University Complutense of Madrid, C/Arcos del Jalon 118, 28032, Madrid, Spain
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19
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Verra DM, Sajdak BS, Merriman DK, Hicks D. Diurnal rodents as pertinent animal models of human retinal physiology and pathology. Prog Retin Eye Res 2019; 74:100776. [PMID: 31499165 DOI: 10.1016/j.preteyeres.2019.100776] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 08/27/2019] [Accepted: 08/31/2019] [Indexed: 12/12/2022]
Abstract
This presentation will survey the retinal architecture, advantages, and limitations of several lesser-known rodent species that provide a useful diurnal complement to rats and mice. These diurnal rodents also possess unusually cone-rich photoreceptor mosaics that facilitate the study of cone cells and pathways. Species to be presented include principally the Sudanian Unstriped Grass Rat and Nile Rat (Arvicanthis spp.), the Fat Sand Rat (Psammomys obesus), the degu (Octodon degus) and the 13-lined ground squirrel (Ictidomys tridecemlineatus). The retina and optic nerve in several of these species demonstrate unusual resilience in the face of neuronal injury, itself an interesting phenomenon with potential translational value.
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Affiliation(s)
- Daniela M Verra
- Department of Neurobiology of Rhythms, Institut des Neurosciences Cellulaires et Intégratives (INCI), CNRS UPR 3212, Strasbourg, France
| | | | - Dana K Merriman
- Department of Biology, University of Wisconsin Oshkosh, Oshkosh, WI, USA
| | - David Hicks
- Department of Neurobiology of Rhythms, Institut des Neurosciences Cellulaires et Intégratives (INCI), CNRS UPR 3212, Strasbourg, France.
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20
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Navarro Gil FJ, Huete-Toral F, Crooke A, Dominguez Godinez CO, Carracedo G, Pintor J. Effect of Melatonin and Its Analogs on Tear Secretion. J Pharmacol Exp Ther 2019; 371:186-190. [PMID: 31371479 DOI: 10.1124/jpet.119.259192] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 07/30/2019] [Indexed: 11/22/2022] Open
Abstract
Melatonin has been shown to enhance tear secretion associated with dinucleotide diadenosine tetraphosphate. This study investigated the isolated action of melatonin and its analogs, agomelatine, N-butanoyl-2-(2-methoxy-6H-isoindolo[2,1-a]indol-11-yl) ethanamine (IIK7), and 5-methoxycarbonylamino-N-cetyltryptamine (5-MCA-NAT) (10 µl at 100 µM), on tear secretion when applied topically in the rabbit cornea and its relationship with the melatonin MT1, MT2, and MT3/quinone reductase QR2 receptors. The results showed a significant increase in tear secretion, with a maximal effect at 60 minutes for the agonists (138.9% ± 6.5%, 128.9% ± 6.4%, and 120.0% ± 5.2%, respectively; P < 0.05; 100% control) but not for melatonin (101.6% ± 7.9%; P > 0.05). Agonist action was tested combined with the antagonists DH97 (MT2 selective), prazosin (MT3/QR2 inhibitor), and luzindole (nonselective MT membrane receptor) (10 µl at 100 µM). DH97 reversed the effect of agomelatine, IIK7, and 5-MCA-NAT up to 30.85% ± 7.6%,108% ± 7.2%, and 87.01% ± 7.6%, respectively (P < 0.05; 100% control). Luzindole antagonized agomelatine and 5-MCA-NAT up to 67.35% ± 7.6% and 92.12% ± 8%, respectively (P < 0.05). Prazosin only reversed 5-MCA-NAT action up to 84.2% ± 7.7% (P < 0.05). These results suggest different pathways for the agonists to act through MT membrane receptors. Therefore, agomelatine, IIK7, and 5-MCA-NAT act through MT membrane receptors as secretagogues of tear secretion, and these analogs could be considered excellent therapeutic candidates for dry eye treatment. SIGNIFICANCE STATEMENT: Currently, dry eye with aqueous deficit is treated by adding artificial tears palliatively. This study shows that topical installation of three melatonin analogs (agomelatine, IIK7, and 5-MCA-NAT), but not melatonin, in therapeutic doses in the rabbit cornea significantly increases tear production, acting through different melatonin membrane receptor subtypes. Therefore, this study suggests that melatoninergic compounds could be considered excellent therapeutic candidates for dry eye treatment and ocular surface diseases occurring with a reduction in tear production.
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Affiliation(s)
- Francisco Javier Navarro Gil
- Departamentos de Optometría y Visión (F.J.N.G., C.O.D.G., G.C.) and Bioquímica y Biología Molecular (F.H.-T., A.C., J.P.), Facultad de Óptica y Optometría, Universidad Complutense de Madrid, Madrid, Spain
| | - Fernando Huete-Toral
- Departamentos de Optometría y Visión (F.J.N.G., C.O.D.G., G.C.) and Bioquímica y Biología Molecular (F.H.-T., A.C., J.P.), Facultad de Óptica y Optometría, Universidad Complutense de Madrid, Madrid, Spain
| | - Almudena Crooke
- Departamentos de Optometría y Visión (F.J.N.G., C.O.D.G., G.C.) and Bioquímica y Biología Molecular (F.H.-T., A.C., J.P.), Facultad de Óptica y Optometría, Universidad Complutense de Madrid, Madrid, Spain
| | - Carmen Olalla Dominguez Godinez
- Departamentos de Optometría y Visión (F.J.N.G., C.O.D.G., G.C.) and Bioquímica y Biología Molecular (F.H.-T., A.C., J.P.), Facultad de Óptica y Optometría, Universidad Complutense de Madrid, Madrid, Spain
| | - Gonzalo Carracedo
- Departamentos de Optometría y Visión (F.J.N.G., C.O.D.G., G.C.) and Bioquímica y Biología Molecular (F.H.-T., A.C., J.P.), Facultad de Óptica y Optometría, Universidad Complutense de Madrid, Madrid, Spain
| | - Jesús Pintor
- Departamentos de Optometría y Visión (F.J.N.G., C.O.D.G., G.C.) and Bioquímica y Biología Molecular (F.H.-T., A.C., J.P.), Facultad de Óptica y Optometría, Universidad Complutense de Madrid, Madrid, Spain
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Ulusoy DM, Akkaya S, Batın S. Evaluation of choroidal changes in adolescent idiopathic scoliosis using enhanced depth imaging optical coherence tomography. Clin Exp Optom 2019; 103:320-323. [PMID: 31210383 DOI: 10.1111/cxo.12932] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 04/25/2019] [Accepted: 05/05/2019] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND We aimed to evaluate the choroidal thickness (CT) in patients with adolescent idiopathic scoliosis (AIS) using enhanced depth imaging optical coherence tomography (EDI-OCT). METHODS In this cross-sectional, observational comparative study, 56 eyes of 56 patients with AIS and 56 eyes of 56 age- and sex-matched healthy subjects were included. All participants underwent complete ophthalmologic examination and CT measurements at the fovea and at 750 μm intervals from the fovea to 1,500 μm in the nasal and temporal site obtained by spectral domain EDI-OCT. RESULTS The mean subfoveal CT was lower in the AIS patients (285.2 ± 24.4 μm) than that of the controls (313.2 ± 28.8 μm; p < 0.001). The difference was also significant at all extrafoveal measurement points (p < 0.001 for all). There were negative correlations of CTs at subfoveal and extrafoveal locations with the Cobb's angle in the AIS patients (for subfoveal location: r = -0.71 and p < 0.001; and for extrafoveal locations: r = -0.66 and p < 0.001 at 750 μm in the nasal side; r = -0.64 and p < 0.001 at 1,500 μm in the nasal side; r = -0.71 and p < 0.001 at 750 μm in the temporal side; and r = -0.69 and p < 0.001 at 1,500 μm in the temporal side). CONCLUSION This preliminary study showed that AIS patients have thinner CT compared to that of healthy subjects. The lower CT was correlated with the increased angle of scoliosis.
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Affiliation(s)
- Döndü Melek Ulusoy
- Department of Ophthalmology, Kayseri Training and Research Hospital, Kayseri, Turkey
| | - Serkan Akkaya
- Department of Ophthalmology, Kayseri Training and Research Hospital, Kayseri, Turkey
| | - Sabri Batın
- Department of Orthopaedics and Traumatology, Kayseri Training and Research Hospital, Kayseri, Turkey
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Circadian circuits in humans: White matter microstructure predicts daytime sleepiness. Cortex 2019; 122:97-107. [PMID: 31097190 DOI: 10.1016/j.cortex.2019.01.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 10/31/2018] [Accepted: 01/14/2019] [Indexed: 11/22/2022]
Abstract
The suprachiasmatic nucleus of the hypothalamus is the chief circadian pacemaker in the brain, and is entrained to day-night cycles by visual afferents from melanopsin containing retinal ganglion cells via the inferior accessory optic tract. Tracer studies have demonstrated efferents from the suprachiasmatic nucleus projecting to the paraventricular nucleus of the hypothalamus, which in turn project to first-order sympathetic neurons in the intermedio-lateral grey of the spinal cord. Sympathetic projections to the pineal gland trigger the secretion of the sleep inducing hormone melatonin. The current study reports the first demonstration of potential sympathopetal hypothalamic projections involved in circadian regulation in humans with in vivo virtual white matter dissections using probabilistic diffusion tensor imaging (DTI) tractography. Additionally, our data shows a correlation between individual differences in white matter microstructure (measured with fractional anisotropy) and increased daytime sleepiness [measured with the Epworth Sleepiness Scale (ESS, Johns, 1991)]. Sympathopetal connections with the hypothalamus were virtually dissected using designated masks on the optic chiasm, which served as an anatomical landmark for retinal fibres projecting to the suprachiasmatic nucleus, and a waypoint mask on the lateral medulla, where hypothalamic projections to the sympathetic nervous system traverse in humans. Sympathopetal projections were demonstrated in each hemisphere in twenty-six subjects. The tract passed through the suprachiasmatic nucleus of the hypothalamus and its trajectory corresponds to the dorsal longitudinal fasciculus traversing the periaqueductal region and the lateral medulla. White matter microstructure (FA) in the left hemisphere correlated with high scores on the ESS, suggesting an association between circadian pathway white matter microstructure, and increased daytime sleepiness.
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Visser HE, Dees DD, Millichamp NJ, Vallone LV, Scott EM. Effect of orally administered melatonin on intraocular pressure of ophthalmologically normal dogs. Am J Vet Res 2019; 80:410-415. [PMID: 30919670 DOI: 10.2460/ajvr.80.4.410] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine the effect of orally administered melatonin on the intraocular pressure (IOP) of ophthalmologically normal dogs. ANIMALS 20 ophthalmologically normal dogs (40 eyes). PROCEDURES In a randomized crossover study, each dog received a 7-day regimen of melatonin (0.1 to 0.2 mg/kg, PO, q 12 h) and a placebo (150 mg of lactose powder in a capsule, PO, q 12 h), with a 7-day washout period between treatment regimens. Rebound tonometry was used to measure the IOP in both eyes of each dog 5 times at 2-hour intervals on days 0 (before administration of the first dose), 2, 4, and 7 (after administration of the last dose) of each treatment period. Repeated-measures ANOVA was used to evaluate the effects of treatment, day, and IOP measurement time within day on IOP. RESULTS Intraocular pressure was not significantly associated with treatment but was associated with day and the interaction between day and IOP measurement time within day. The mean ± SD IOP was 14.26 ± 2.95 and 14.34 ± 2.69 mm Hg for the melatonin and placebo regimens, respectively. Within each treatment period, the mean IOP tended to decrease from day 0 to 7 as well as within each day, which was attributed to the dogs becoming acclimated to the study protocol and natural diurnal variations in IOP. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that oral administration of melatonin (0.1 to 0.2 mg/kg, q 12 h for 7 d) did not significantly affect the IOP of ophthalmologically normal dogs.
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Nishimon S, Nishimon M, Nishino S. Tasimelteon for treating non-24-h sleep-wake rhythm disorder. Expert Opin Pharmacother 2019; 20:1065-1073. [DOI: 10.1080/14656566.2019.1603293] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Shohei Nishimon
- Sleep and Circadian Neurobiology Laboratory, Psychiatry and Behavior Sciences, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Mari Nishimon
- Sleep and Circadian Neurobiology Laboratory, Psychiatry and Behavior Sciences, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Seiji Nishino
- Sleep and Circadian Neurobiology Laboratory, Psychiatry and Behavior Sciences, Stanford University School of Medicine, Palo Alto, CA, USA
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25
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An insight into the scientific background and future perspectives for the potential uses of melatonin. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.ejbas.2015.05.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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26
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Abd-Elsalam WH, ElKasabgy NA. Mucoadhesive olaminosomes: A novel prolonged release nanocarrier of agomelatine for the treatment of ocular hypertension. Int J Pharm 2019; 560:235-245. [PMID: 30763680 DOI: 10.1016/j.ijpharm.2019.01.070] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Revised: 01/18/2019] [Accepted: 01/31/2019] [Indexed: 11/24/2022]
Abstract
Mucoadhesive olaminosomes are novel nanocarriers designed to control agomelatine release and enhance its bioavailability. Olaminosomes were prepared using oleic acid, oleylamine and sorbitan monooleate adopting thin film hydration technique. Chitosan HCl was added to impart the mucoadhesive properties to the olaminosomes. Mucoadhesive olaminosomes were characterized for their particle size, in-vitro drug release and irritation potentiality in rabbit eyes. The reduction in intraocular pressure (IOP) through 8 h in male New Zealand Albino rabbits was measured after administration of the selected formulations. Histopathological changes in rabbits' eye were also evaluated. Results revealed that increasing the amount of the added oleylamine decreased the particle size of the resulted vesicles and increased the drug release rate. Olaminosomes showed enhanced drug absorption, hence more reduction in IOP was observed. Moreover, using chitosan HCl might increase the residence time of the formulation in the eye and hence improved the absorption of the drug. No histopathological changes in rabbits' eye were detected after the application of mucoadhesive olaminosomes concluding their safety on the ocular tissues. In conclusion, mucoadhesive olaminosomes succeeded in enhancing agomelatine bioavailability in rabbits' eyes confirming the development of a novel ocular nanocarrier for insoluble drugs.
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Affiliation(s)
- Wessam H Abd-Elsalam
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Nermeen A ElKasabgy
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Cairo University, Cairo, Egypt.
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27
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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]
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28
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Ba-Ali S, Brøndsted AE, Andersen HU, Sander B, Jennum PJ, Lund-Andersen H. Assessment of diurnal melatonin, cortisol, activity, and sleep-wake cycle in patients with and without diabetic retinopathy. Sleep Med 2018; 54:35-42. [PMID: 30529775 DOI: 10.1016/j.sleep.2018.10.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 09/20/2018] [Accepted: 10/02/2018] [Indexed: 12/23/2022]
Abstract
OBJECTIVE To assess the diurnal melatonin, cortisol, and activity/rest levels, as well as sleep quality, in patients with and without nonproliferative diabetic retinopathy (DR). METHODS We included 25 diabetic patients with DR and 29 without DR. A total of 21 healthy subjects constituted the control group. We assessed the circadian rhythm by actigraphy and diurnal salivary melatonin and cortisol measurements. Sleep quality was evaluated by actigraphy and the Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) questionnaires. Light exposure was quantified by actigraphy. The primary outcome was peak salivary melatonin level. Secondary outcomes were mean melatonin and cortisol levels during dark hours, activity-rest rhythm, sleep quality, as well as level of white, red, green, and blue light exposure. RESULTS Peak melatonin concentration at 04:00 and mean nocturnal melatonin level were significantly reduced in all diabetic patients, regardless of retinopathy stage (p < 0.001). Levels of light exposures during dark hours were not significantly different in patients with and without DR and healthy controls. Only patients with DR showed increased intradaily variability in their activity-rest interval, indicating circadian misalignment (p = 0.04). Neither the objective actigraphic sleep quality parameters nor the subjective PSQI or ESS scores were significantly different between healthy controls and diabetic patients. CONCLUSIONS Reduced nocturnal melatonin concentration and increased fragmentation of activity-rest intervals revealed circadian rhythm disturbance in diabetic patients with DR.
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Affiliation(s)
- Shakoor Ba-Ali
- Department of Ophthalmology, Rigshospitalet, Glostrup, Denmark; Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | | | | | - Birgit Sander
- Department of Ophthalmology, Rigshospitalet, Glostrup, Denmark
| | - Poul Jørgen Jennum
- Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Danish Centre for Sleep Medicine, Neurophysiology Clinic, Rigshospitalet, Glostrup, Denmark
| | - Henrik Lund-Andersen
- Department of Ophthalmology, Rigshospitalet, Glostrup, Denmark; Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Xu Z, Wu Y, Zhang Y, Zhang H, Shi L. Melatonin activates BK Ca channels in cerebral artery myocytes via both direct and MT receptor/PKC-mediated pathway. Eur J Pharmacol 2018; 842:177-188. [PMID: 30391348 DOI: 10.1016/j.ejphar.2018.10.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Revised: 10/17/2018] [Accepted: 10/24/2018] [Indexed: 11/28/2022]
Abstract
The pineal hormone melatonin is a neuroendocrine hormone with high membrane permeability that is involved in regulation of circadian rhythm of several biological functions. Large-conductance Ca2+-activated K+ (BKCa) channels are abundantly expressed in vascular smooth muscle cells and play an important role in vascular tone regulation. We investigated the mechanisms through which myocyte BKCa channels mediate effects of melatonin on cerebral arteries (CAs). Arterial contractility measurements showed that melatonin alone did not change vascular tone in CAs; however, it induced concentration-dependent vasodilation of phenylephrine-induced contraction in CAs. In the presence of the potent endothelial oxide synthase inhibitor, Nω-nitro-L-arginine methyl ester, melatonin-elicited relaxation was significantly inhibited by iberiotoxin (BKCa channel blocker). Melatonin significantly increased BKCa currents but not voltage-gated K+ (KV) currents in whole-cell recordings. Melatonin decreased the amplitude of Ca2+ sparks and spontaneous transient outward currents (STOCs), however, a significant increase in open probability of BKCa channels was observed in both inside-out and cell-attached patch-clamp recordings. This melatonin-induced enhancement of BKCa channel activity was significantly suppressed by luzindole (melatonin MT1/MT2 receptor inhibitor), U73122 (phospholipase C (PLC) inhibitor), and Ro31-8220 (protein kinase C (PKC) inhibitor). Melatonin had no significant effects on sarcoplasmic reticulum release of Ca2+. These findings indicate that melatonin-induced vasorelaxation of CAs is partially attributable to direct (passing through the cell membrane) and indirect (via melatonin MT1/MT2 receptors-PLC-PKC pathway) activation of BKCa channels on CA myocytes.
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Affiliation(s)
- Zhaoxia Xu
- Department of Exercise Physiology, Beijing Sport University, Beijing 100084, China
| | - Ying Wu
- Department of Exercise Physiology, Beijing Sport University, Beijing 100084, China
| | - Yanyan Zhang
- Department of Exercise Physiology, Beijing Sport University, Beijing 100084, China
| | - Huirong Zhang
- Department of Exercise Physiology, Beijing Sport University, Beijing 100084, China
| | - Lijun Shi
- Department of Exercise Physiology, Beijing Sport University, Beijing 100084, China.
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30
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Spadoni G, Bedini A, Furiassi L, Mari M, Mor M, Scalvini L, Lodola A, Ghidini A, Lucini V, Dugnani S, Scaglione F, Piomelli D, Jung KM, Supuran CT, Lucarini L, Durante M, Sgambellone S, Masini E, Rivara S. Identification of Bivalent Ligands with Melatonin Receptor Agonist and Fatty Acid Amide Hydrolase (FAAH) Inhibitory Activity That Exhibit Ocular Hypotensive Effect in the Rabbit. J Med Chem 2018; 61:7902-7916. [DOI: 10.1021/acs.jmedchem.8b00893] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Gilberto Spadoni
- Dipartimento di Scienze Biomolecolari, Università degli Studi di Urbino “Carlo Bo”, Piazza Rinascimento 6, I-61029 Urbino, Italy
| | - Annalida Bedini
- Dipartimento di Scienze Biomolecolari, Università degli Studi di Urbino “Carlo Bo”, Piazza Rinascimento 6, I-61029 Urbino, Italy
| | - Lucia Furiassi
- Dipartimento di Scienze Biomolecolari, Università degli Studi di Urbino “Carlo Bo”, Piazza Rinascimento 6, I-61029 Urbino, Italy
| | - Michele Mari
- Dipartimento di Scienze Biomolecolari, Università degli Studi di Urbino “Carlo Bo”, Piazza Rinascimento 6, I-61029 Urbino, Italy
| | - Marco Mor
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università degli Studi di Parma, Parco Area delle Scienze 27/A I-43124 Parma, Italy
| | - Laura Scalvini
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università degli Studi di Parma, Parco Area delle Scienze 27/A I-43124 Parma, Italy
| | - Alessio Lodola
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università degli Studi di Parma, Parco Area delle Scienze 27/A I-43124 Parma, Italy
| | - Andrea Ghidini
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università degli Studi di Parma, Parco Area delle Scienze 27/A I-43124 Parma, Italy
| | - Valeria Lucini
- Dipartimento di Oncologia ed Emato-Oncologia, Università degli Studi di Milano, Via Vanvitelli 32, I-20129 Milano, Italy
| | - Silvana Dugnani
- Dipartimento di Oncologia ed Emato-Oncologia, Università degli Studi di Milano, Via Vanvitelli 32, I-20129 Milano, Italy
| | - Francesco Scaglione
- Dipartimento di Oncologia ed Emato-Oncologia, Università degli Studi di Milano, Via Vanvitelli 32, I-20129 Milano, Italy
| | - Daniele Piomelli
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università degli Studi di Parma, Parco Area delle Scienze 27/A I-43124 Parma, Italy
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, California 92697, United States
| | - Kwang-Mook Jung
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, California 92697, United States
| | - Claudiu T. Supuran
- Dipartimento NEUROFARBA, Sezione di Scienze Farmaceutiche e Nutraceutiche, Università degli Studi di Firenze, via Ugo Shiff 6, I-50019 Sesto Fiorentino (FI), Italy
| | - Laura Lucarini
- Dipartimento NEUROFARBA, Sezione di Farmacologia e Tossicologia, Università degli Studi di Firenze, Viale G. Pieraccini 6, I-50019 Firenze, Italy
| | - Mariaconcetta Durante
- Dipartimento NEUROFARBA, Sezione di Farmacologia e Tossicologia, Università degli Studi di Firenze, Viale G. Pieraccini 6, I-50019 Firenze, Italy
| | - Silvia Sgambellone
- Dipartimento NEUROFARBA, Sezione di Farmacologia e Tossicologia, Università degli Studi di Firenze, Viale G. Pieraccini 6, I-50019 Firenze, Italy
| | - Emanuela Masini
- Dipartimento NEUROFARBA, Sezione di Farmacologia e Tossicologia, Università degli Studi di Firenze, Viale G. Pieraccini 6, I-50019 Firenze, Italy
| | - Silvia Rivara
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università degli Studi di Parma, Parco Area delle Scienze 27/A I-43124 Parma, Italy
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Abstract
PURPOSE OF REVIEW Sleep timing, quantity, and quality are controlled by homeostatic and circadian systems. Circadian clock systems are present in all cells and organs and their timing is determined by a transcriptional-translational feedback loop of circadian genes. Individual cellular clocks are synchronized by the central body clock, situated in the suprachiasmatic nucleus, which communicates with them through humoral and neural signals including melatonin. The circadian system controls both the circadian period: (i.e., the length of the intrinsic clock), but also the circadian phase (i.e., the clock timing). An important determinant of the circadian system is light exposure. In most humans, the circadian period is slightly longer than 24 h and without regular resetting it tends to drift, leading to progressively later bedtimes and wake times and a tendency to cycle though periods of normal and abnormal sleep. Blind patients are thus at an increased risk of abnormal circadian function. The purpose of this article is to review recent research and clinical management of circadian rhythm disorders in blind patients. RECENT FINDINGS Blind patients can present delayed and advanced sleep phase disorders but the most common abnormality in totally blind patients without light perception is non-24-hour sleep-wake disorder (N24SWD). This is rare in the general population but may affect up to 50% of blind patients without light perception. The diagnosis of a circadian rhythm disorder in the blind is complex. New screening tools have been developed but actigraphy and repeated melatonin profiles over 24 h remain essential. Circadian disorders in the blind are frequent, especially in the patients without light perception. They require accurate diagnosis in order to target treatment. Determining the precise nature of a sleep disorder in blind patients with a suspected circadian rhythm abnormality is complex and requires a detailed clinical history with sleep diaries and the use of actigraphy and melatonin profiles.
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Quera Salva MA, Hartley S, Léger D, Dauvilliers YA. Non-24-Hour Sleep-Wake Rhythm Disorder in the Totally Blind: Diagnosis and Management. Front Neurol 2017; 8:686. [PMID: 29326647 PMCID: PMC5741691 DOI: 10.3389/fneur.2017.00686] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 12/01/2017] [Indexed: 12/18/2022] Open
Abstract
Several aspects of human physiology and behavior are dominated by 24-h circadian rhythms with key impacts on health and well-being. These include mainly the sleep–wake cycle, vigilance and performance patterns, and some hormone secretions. The rhythms are generated spontaneously by an internal “pacemaker,” the suprachiasmatic nuclei within the anterior hypothalamus. This master clock has, for most humans, an intrinsic rhythm slightly longer than 24 h. Daily retinal light exposure is necessary for the synchronization of the circadian rhythms with the external 24-h solar environment. This daily synchronization process generally poses no problems for sighted individuals except in the context of jetlag or working night shifts being conditions of circadian desynchrony. However, many blind subjects with no light perception had periodical circadian desynchrony, in the absence of light information to the master clock leading to poor circadian rhythm synchronization. Affected patients experience cyclical or periodic episodes of poor sleep and daytime dysfunction, severely interfering with social, academic, and professional life. The diagnosis of Non-24 Sleep–Wake Rhythm Disorder, also named free-running disorder, non-entrained disorder, or hypernycthemeral syndrome, remains challenging from a clinical point of view due to the cyclical symptoms and should be confirmed by measurements of circadian biomarkers such as urinary melatonin to demonstrate a circadian period outside the normal range. Management includes behavioral modification and melatonin. Tasimelteon, a novel melatonin receptor 1 and 2 agonist, has demonstrated its effectiveness and safety with an evening dose of 20 mg and is currently the only treatment approved by the FDA and the European Medicines Agency.
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Affiliation(s)
- Maria Antonia Quera Salva
- AP-HP Hôpital Raymond Poincaré, Sleep Unit, Physiology Department, Versailles Saint-Quentin-en-Yvelines University, Garches, France
| | - Sarah Hartley
- AP-HP Hôpital Raymond Poincaré, Sleep Unit, Physiology Department, Versailles Saint-Quentin-en-Yvelines University, Garches, France
| | - Damien Léger
- Université Paris Descartes, Sorbonne Paris Cité, APHP, Hôtel-Dieu, Centre du Sommeil et de la Vigilance et, Paris, France
| | - Yves A Dauvilliers
- Sleep-Wake Disorders Center, Department of Neurology, Gui de Chauliac Hospital, National Reference Network for Narcolepsy, INSERM U1061, Montpellier, France
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Andrés-Guerrero V, Bravo-Osuna I, Pastoriza P, Molina-Martinez IT, Herrero-Vanrell R. Novel technologies for the delivery of ocular therapeutics in glaucoma. J Drug Deliv Sci Technol 2017. [DOI: 10.1016/j.jddst.2017.07.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Cao J, Bian J, Wang Z, Dong Y, Chen Y. Effect of monochromatic light on circadian rhythmic expression of clock genes and arylalkylamine N-acetyltransferase in chick retina. Chronobiol Int 2017; 34:1149-1157. [PMID: 28910542 DOI: 10.1080/07420528.2017.1354013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Birds have more developed visual function. They not only have the ability to detect light and darkness but also have the color vision. Previous study showed that monochromatic light influenced avian physiological processes, which were controlled by clock genes. Therefore, bird's eye is a good model to studying the impact of color of light on circadian rhythms. Avian retina is one of the most important central oscillations. The study was designed to investigate the effect of color of light on the expression of clock genes and arylalkylamine N-acetyltransferase (Aanat) mRNA expression in chick retina. A total of 240 post-hatching day (P) 0 broiler chickens were exposed to blue (BL), green (GL), red (RL) and white light (WL) from a LED system under a light-dark cycle 12L:12D for 14 d. The results show that the significant daily variations existed in the gene expression of cBmal1, cBmal2, cCry1, cCry2, cPer2 and cPer3, but not for cClock under four light treatments. The genes cBmal1, cCry1, cPer2 and cPer3 presented circadian rhythmic expression under the various monochromatic lights. When compared with WL, GL elevated the expression of positive regulators of cellular clock (cBmal1, cBmal2 and cClock) and cAanat mRNA level, whereas RL increased the mRNA levels of negative regulators of cellular clock (cCry1, cCry2, cPer2 and cPer3) and decreased the cAanat mRNA expression in the retina. These results demonstrated that monochromatic light affect the periodic expression levels of the biological clock mRNA by positive and negative feedback loop interactions, GL activated the transcription of cAanat; while RL suppressed the transcription of cAanat. Thereby, color of light regulates ocular cAanat expression by affecting on expression of cellular clock regulators.
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Affiliation(s)
- Jing Cao
- a Laboratory of Anatomy of Domestic Animal, College of Animal Medicine , China Agricultural University , Beijing , China
| | - Jiang Bian
- a Laboratory of Anatomy of Domestic Animal, College of Animal Medicine , China Agricultural University , Beijing , China
| | - Zixu Wang
- a Laboratory of Anatomy of Domestic Animal, College of Animal Medicine , China Agricultural University , Beijing , China
| | - Yulan Dong
- a Laboratory of Anatomy of Domestic Animal, College of Animal Medicine , China Agricultural University , Beijing , China
| | - Yaoxing Chen
- a Laboratory of Anatomy of Domestic Animal, College of Animal Medicine , China Agricultural University , Beijing , China
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35
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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: 43] [Impact Index Per Article: 6.1] [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.
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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
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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.
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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
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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.
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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]
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Carracedo G, Carpena C, Concepción P, Díaz V, García-García M, Jemni N, Lledó VE, Martín M, Pastrana C, Pelissier R, Veselinova A, Wang X, Pintor J. Presence of melatonin in human tears. JOURNAL OF OPTOMETRY 2017; 10:3-4. [PMID: 27085976 PMCID: PMC5219833 DOI: 10.1016/j.optom.2016.03.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Revised: 03/02/2016] [Accepted: 03/08/2016] [Indexed: 05/28/2023]
Affiliation(s)
- Gonzalo Carracedo
- Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain; Department of Optics II (Optometry and Visión) and Molecular Biology IV, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain.
| | - Carlos Carpena
- Master of Optometry and Vision, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Pablo Concepción
- Master of Optometry and Vision, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Victor Díaz
- Master of Optometry and Vision, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Miguel García-García
- Master of Optometry and Vision, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Nahla Jemni
- Master of Optometry and Vision, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Victoria Eugenia Lledó
- Master of Optometry and Vision, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Marina Martín
- Master of Optometry and Vision, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Cristina Pastrana
- Master of Optometry and Vision, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Raquel Pelissier
- Master of Optometry and Vision, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Albena Veselinova
- Master of Optometry and Vision, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Xiaoyu Wang
- Master of Optometry and Vision, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Jesus Pintor
- Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
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Melatonin in Retinal Physiology and Pathology: The Case of Age-Related Macular Degeneration. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:6819736. [PMID: 27688828 PMCID: PMC5027321 DOI: 10.1155/2016/6819736] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 08/09/2016] [Indexed: 12/16/2022]
Abstract
Melatonin, an indoleamine, is synthesized mainly in the pineal gland in a circadian fashion, but it is produced in many other organs, including the retina, which seems to be especially important as the eye is a primary recipient of circadian signals. Melatonin displays strong antioxidative properties, which predispose it to play a protective role in many human pathologies associated with oxidative stress, including premature aging and degenerative disease. Therefore, melatonin may play a role in age-related macular degeneration (AMD), a disease affecting photoreceptors, and retinal pigment epithelium (RPE) with an established role of oxidative stress in its pathogenesis. Several studies have shown that melatonin could exert the protective effect against damage to RPE cells evoked by reactive oxygen species (ROS), but it has also been reported to increase ROS-induced damage to photoreceptors and RPE. Melatonin behaves like synthetic mitochondria-targeted antioxidants, which concentrate in mitochondria at relatively high levels; thus, melatonin may prevent mitochondrial damage in AMD. The retina contains telomerase, an enzyme implicated in maintaining the length of telomeres, and oxidative stress inhibits telomere synthesis, while melatonin overcomes this effect. These features support considering melatonin as a preventive and therapeutic agent in the treatment of AMD.
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Lai YH, Hu DN, Rosen R, Sassoon J, Chuang LY, Wu KY, Wu WC. Hypoxia-induced vascular endothelial growth factor secretion by retinal pigment epithelial cells is inhibited by melatonin via decreased accumulation of hypoxia-inducible factors-1α protein. Clin Exp Ophthalmol 2016; 45:182-191. [PMID: 27409056 DOI: 10.1111/ceo.12802] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 06/30/2016] [Accepted: 07/05/2016] [Indexed: 01/05/2023]
Abstract
BACKGROUND Hypoxia is the most important stimulus leading to up-regulation of vascular endothelial growth factor (VEGF) in the retina via elevation of hypoxia-inducible factors-1α (HIF-1α) protein. The purpose of this study was to test the effects of melatonin on the expression of VEGF and HIF-1α in the cultured human retinal pigment epithelial (RPE) cells under normoxia and hypoxia. METHOD An in vitro RPE cell hypoxia model was established by placing cells under 1% oxygen pressure or by adding cobalt chloride (CoCl2 ) to the culture medium. RPE cells and conditioned media were collected from cultures treated with and without melatonin under normoxia and hypoxia. The protein and RNA levels of VEGF and HIF-1α were measured by ELISA kits and RT-PCR, respectively. RESULT Hypoxia induced a significant increase of expression and secretion of VEGF and accumulation of HIF-1α protein in RPE cells (P < 0.05). Melatonin at 10-5 to 10-8 M significantly inhibited hypoxia-induced expression, the secretion of VEGF and the accumulation of HIF-1α protein (P < 0.05), but not affected expression of VEGF and HIF-1α under normoxia (P > 0.05). CONCLUSION This study suggests that melatonin may have potential value in the prevention and treatment of various retinal diseases associated with increase of VEGF, vascular leakage and angiogenesis.
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Affiliation(s)
- Yu-Hung Lai
- Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.,Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Dan-Ning Hu
- New York Eye and Ear Infirmary of Mount Sinai, New York, New York, USA.,Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Richard Rosen
- New York Eye and Ear Infirmary of Mount Sinai, New York, New York, USA.,Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Jodi Sassoon
- New York Eye and Ear Infirmary of Mount Sinai, New York, New York, USA
| | - Lea-Yea Chuang
- Department of Biochemistry, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Kwou-Yeung Wu
- Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Wen-Chuan Wu
- Department of Ophthalmology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
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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.
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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
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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]
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Pescosolido N, Gatto V, Stefanucci A, Rusciano D. Oral treatment with the melatonin agonist agomelatine lowers the intraocular pressure of glaucoma patients. Ophthalmic Physiol Opt 2015; 35:201-5. [DOI: 10.1111/opo.12189] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2014] [Accepted: 11/29/2014] [Indexed: 01/21/2023]
Affiliation(s)
- Nicola Pescosolido
- Facoltà di Medicina e Odontoiatria; Università di Roma La Sapienza; Rome Italy
| | - Vittorio Gatto
- Facoltà di Medicina e Odontoiatria; Università di Roma La Sapienza; Rome Italy
| | - Alessio Stefanucci
- Facoltà di Medicina e Odontoiatria; Università di Roma La Sapienza; Rome Italy
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Gahr M. Agomelatine in the treatment of major depressive disorder: an assessment of benefits and risks. Curr Neuropharmacol 2014; 12:287-398. [PMID: 25426008 PMCID: PMC4243030 DOI: 10.2174/1570159x12999140619122914] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 05/29/2014] [Accepted: 06/01/2014] [Indexed: 12/13/2022] Open
Abstract
Agomelatine (AGM) was approved for the treatment of major depressive disorder (MDD) in adults by the European Medicines Agency (EMA) in February 2009. It is an analogue of melatonin and features a unique pharmacodynamic profile with agonism on both types of melatonergic receptors (MT1/MT2) and antagonism at serotonergic 5-HT2C receptors. There is, however, an ongoing debate regarding the efficacy and safety of this novel antidepressant agent, originally evoked by claims of a significant publication bias underlying the assessment of AGM being an effective antidepressant. Indeed, two recent comprehensive metaanalyses of published and unpublished clinical trials found evidence for a relevant publication bias. However, due to its statistically significant advantage over placebo based on the results of these metaanalyses AGM must be referred to as an effective antidepressant agent in the acute phase of MDD. However, the effect sizes of AGM in the treatment of MDD were evaluated as being small in comparison to other antidepressant agents. In addition, there is insufficient evidence for the efficacy of AGM in relapse prevention of MDD. Apart from efficacy issues, AGM appears to have the potential to exhibit severe hepatotoxicity (the EMA has identified AGM-associated “hepatotoxic reactions” as a new safety concern in September 2013) that is currently poorly understood. Considering these aspects, it seems inappropriate to evaluate AGM as an antidepressant agent of first choice. Nevertheless, its unique mechanism of action with particular sleep modulating effects may represent a specific treatment strategy for patients with particular characteristics; further studies with thorough characterization of patients are needed to test this hypothesis.
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Affiliation(s)
- Maximilian Gahr
- University of Ulm, Department of Psychiatry and Psychotherapy III. Leimgrubenweg 12-14, 89075 Ulm, Ulm, Germany
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Leonardi A, Bucolo C, Drago F, Salomone S, Pignatello R. Cationic solid lipid nanoparticles enhance ocular hypotensive effect of melatonin in rabbit. Int J Pharm 2014; 478:180-186. [PMID: 25448580 DOI: 10.1016/j.ijpharm.2014.11.032] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 11/11/2014] [Accepted: 11/13/2014] [Indexed: 01/29/2023]
Abstract
The study was aimed at evaluating whether the ocular hypotensive effect of melatonin (MEL) was enhanced by its encapsulation in cationic solid lipid nanoparticles (cSLN), as well as at determining the tolerability of these formulations on the ocular surface. MEL was loaded in cSLN that had already been shown to be suitable for ophthalmic use. The formulations were prepared using Softisan(®) 100 as the main lipid matrix, with the presence of either stearic (SA) or palmitic acid (PA) as lipid modifiers. A fixed positive charge was provided by the addition of a cationic lipid (didecyldimethylammonium bromide). The ocular hypotensive effect was evaluated by measuring the intraocular pressure (IOP) during 24h in albino rabbits. MEL elicited a significant (p<0.01) IOP reduction in rabbit eye. All the formulations tested in vivo demonstrated a good tolerability. The nanocarrier containing SA was the most effective in terms of IOP reduction (maximum IOP reduction: -7 mmHg), and its effect lasted approximately 24h. The experimental data indicate that the new formulations based on cSLN loaded with MEL represent a potent anti-glaucoma treatment with a safe profile, warranting further clinical evaluation of the proposed nanotechnological strategy.
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Affiliation(s)
- Antonio Leonardi
- NANO-i, Research Center of Ocular Nanotechnology, Department of Drug Sciences, University of Catania, Catania, Italy
| | - Claudio Bucolo
- Department of Clinical and Molecular Biomedicine, Section of Pharmacology and Biochemistry, School of Medicine, University of Catania, Viale A. Doria 6, Catania 95125, Italy.
| | - Filippo Drago
- Department of Clinical and Molecular Biomedicine, Section of Pharmacology and Biochemistry, School of Medicine, University of Catania, Viale A. Doria 6, Catania 95125, Italy
| | - Salvatore Salomone
- Department of Clinical and Molecular Biomedicine, Section of Pharmacology and Biochemistry, School of Medicine, University of Catania, Viale A. Doria 6, Catania 95125, Italy
| | - Rosario Pignatello
- NANO-i, Research Center of Ocular Nanotechnology, Department of Drug Sciences, University of Catania, Catania, Italy
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Huete-Toral F, Crooke A, Martínez-Águila A, Pintor J. Melatonin receptors trigger cAMP production and inhibit chloride movements in nonpigmented ciliary epithelial cells. J Pharmacol Exp Ther 2014; 352:119-28. [PMID: 25344385 DOI: 10.1124/jpet.114.218263] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Melatonin and its analog 5-MCA-NAT (5-methylcarboxyamino-N-acetyl tryptamine) are active compounds reducing intraocular pressure (IOP). This action is mediated through MT2 and the putative MT3 melatonin receptor, producing a transient reduction of IOP that lasts for a few hours and has not yet been characterized. The use of melatonin and its analog are causing a decrease in chloride efflux from rabbit nonpigmented epithelial cells (NPE), possibly explaining the decrease in IOP. Melatonin and 5-MCA-NAT inhibited rabbit NPE chloride release in a concentration-dependent manner, whereas the pD2 values were between 4.5 ± 1.2 and 4.4 ± 1.0, respectively. Melatonin hypotensive action was enhanced by the presence of MT2 antagonists, such as DH97 (N-pentanoyl-2-benzyltryptamine) and 4-P-P-DOT (4-phenyl-2-propionamidotetralin) and by the nonselective melatonin receptor antagonist luzindole. Prazosin (1.5 µM) partially reverses the melatonin action by acting as a selective MT3 antagonist. However, at 15 nM it acts as an α-adrenergic receptor antagonist, enhancing the melatonin effect. Regarding the intracellular pathways triggered by melatonin receptors, neither phospholipase C/protein kinase C pathway nor the canonical reduction of intracellular cAMP was responsible for melatonin or 5-MCA-NAT actions. On the contrary, the application of these substances produced a concentration-dependent increase of cAMP, with pD2 values of 4.6 ± 0.2 and 4.9 ± 0.7 for melatonin and 5-MCA-NAT, respectively. In summary, melatonin reduces the release of chloride concomitantly to cAMP generation. The reduction of Cl(-) secretion accounts for a decrease in the water outflow and therefore a decrease in aqueous humor production. This could be one of the main mechanisms responsible for the reduction of IOP after application of melatonin and 5-MCA-NAT.
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Affiliation(s)
- Fernando Huete-Toral
- Departamento de Bioquímica y Biología Molecular IV, Facultad de Óptica y Optometría, Universidad Complutense de Madrid, Madrid, Spain
| | - Almudena Crooke
- Departamento de Bioquímica y Biología Molecular IV, Facultad de Óptica y Optometría, Universidad Complutense de Madrid, Madrid, Spain
| | - Alejandro Martínez-Águila
- Departamento de Bioquímica y Biología Molecular IV, Facultad de Óptica y Optometría, Universidad Complutense de Madrid, Madrid, Spain
| | - Jesús Pintor
- Departamento de Bioquímica y Biología Molecular IV, Facultad de Óptica y Optometría, Universidad Complutense de Madrid, Madrid, Spain
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Tök L, Nazıroğlu M, Doğan S, Kahya MC, Tök O. Effects of melatonin on Wi-Fi-induced oxidative stress in lens of rats. Indian J Ophthalmol 2014; 62:12-5. [PMID: 24492496 PMCID: PMC3955064 DOI: 10.4103/0301-4738.126166] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Introduction: Melatonin has been considered a potent antioxidant that detoxifies a variety of reactive oxygen species in many pathophysiological states of eye. The present study was designed to determine the effects of Wi-Fi exposure on the lens oxidant, antioxidant redox systems, as well as the possible protective effects of melatonin on the lens injury induced by electromagnetic radiation (EMR). Materials and Methods: Thirty-two rats were used in the current study and they were randomly divided into four equal groups as follows: First and second groups were cage-control and sham-control rats. Rats in third group were exposed to Wi-Fi (2.45 GHz) for duration of 60 min/day for 30 days. As in the third group, the fourth group was treated with melatonin. The one-hour exposure to irradiation in second, third and fourth took place at noon each day. Results: Lipid peroxidation levels in the lens were slightly higher in third (Wi-Fi) group than in cage and sham control groups although their concentrations were significantly (P < 0.05) decreased by melatonin supplementation. Glutathione peroxidase (GSH-Px) activity was significantly (P < 0.05) lower in Wi-Fi group than in cage and sham control groups although GSH-Px (P < 0.01) and reduced glutathione (P < 0.05) values were significantly higher in Wi-Fi + melatonin group than in Wi-Fi group. Conclusions: There are poor oxidative toxic effects of one hour of Wi-Fi exposure on the lens in the animals. However, melatonin supplementation in the lens seems to have protective effects on the oxidant system by modulation of GSH-Px activity.
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Affiliation(s)
| | - Mustafa Nazıroğlu
- Department of Biophysics, Medical Faculty, Süleyman Demirel University, Isparta, Turkey
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Crooke A, Guzman-Aranguez A, Mediero A, Alarma-Estrany P, Carracedo G, Pelaez T, Peral A, Pintor J. Effect of melatonin and analogues on corneal wound healing: involvement of Mt2 melatonin receptor. Curr Eye Res 2014; 40:56-65. [PMID: 24892818 DOI: 10.3109/02713683.2014.914540] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
PURPOSE We have investigated the effect of melatonin and its analogues on rabbit corneal epithelial wound healing. METHODS New Zealand rabbits were anaesthetised and wounds were made by placing Whatman paper discs soaked in n-heptanol on the cornea. Melatonin and analogues (all 10 nmol) were instilled. Wound diameter was measured every 2 hours by means of fluorescein application with a Topcon SL-8Z slit lamp. Melatonin antagonists (all 10 nmol) were applied 2 hours before the application of the n-heptanol-soaked disc and then every 6 hours together with melatonin. To confirm the presence of MT2 receptors in corneal epithelial cells immunohistochemistry, Western blot and RT-PCR assays in native tissue and in rabbit corneal epithelial cells were performed. The tear components were extracted then processed by HPLC to quantify melatonin in tears. RESULTS Migration assays revealed that melatonin and particularly the treatment with the MT2 agonist IIK7, accelerated the rate of healing (p < 0.001). The application of the non-selective melatonin receptor antagonist luzindole and the MT2 antagonist DH97 (but not prazosin), prevented the effect of melatonin on wound healing (both p < 0.001). Immunohistochemistry, Western blot and RT-PCR assays showed the presence of MT2 melatonin receptor in corneal epithelial cells. In addition, we have identified melatonin in tears and determined its daily variations. CONCLUSIONS These data suggest that MT2 receptors are implicated in the effect of melatonin on corneal wound healing regulating migration rate. This suggests the potential use of melatonin and its analogues to enhance epithelial wound healing in ocular surface disease.
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Affiliation(s)
- Almudena Crooke
- Departamento de Bioquímica y Biología Molecular IV, Facultad de Óptica y Optometría, Universidad Complutense de Madrid , Madrid , Spain , and
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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.
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