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Prajapati P, Kumar A, Mangrulkar S, Chaple DR, Saraf SA, Kushwaha S. Azilsartan prevents muscle loss and fast- to slow-twitch muscle fiber shift in natural ageing sarcopenic rats. Can J Physiol Pharmacol 2024; 102:342-360. [PMID: 38118126 DOI: 10.1139/cjpp-2023-0265] [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] [Indexed: 12/22/2023]
Abstract
Sarcopenia is a musculoskeletal disease that reduces muscle mass and strength in older individuals. The study investigates the effects of azilsartan (AZL) on skeletal muscle loss in natural sarcopenic rats. Male Sprague-Dawley rats aged 4-6 months and 18-21 months were selected as young-matched control and natural-aged (sarcopenic) rats, respectively. Rats were allocated into young and old control (YC and OC) and young and old AZL treatment (YT and OT) groups, which received vehicles and AZL (8 mg/kg, orally) for 6 weeks. Rats were then sacrificed after muscle function analysis. Serum and gastrocnemius (GN) muscles were isolated for further endpoints. AZL significantly improved muscle grip strength and antioxidant levels in sarcopenic rats. AZL also restored the levels of insulin, testosterone, and muscle biomarkers such as myostatin and creatinine kinase in sarcopenic rats. Furthermore, AZL treatment improved the cellular and ultrastructure of GN muscle and prevented the shift of type II (glycolytic) myofibers to type I (oxidative) myofibers. The results showed that AZL intervention restored protein synthesis in natural sarcopenic rats by increasing p-Akt-1 and decreasing muscle RING-finger protein-1 and tumor necrosis factor alpha immunoexpressions. In conclusion, the present findings showed that AZL could be an effective intervention in treating age-related muscle impairments.
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MESH Headings
- Animals
- Sarcopenia/prevention & control
- Sarcopenia/metabolism
- Sarcopenia/drug therapy
- Sarcopenia/pathology
- Male
- Oxadiazoles/pharmacology
- Oxadiazoles/therapeutic use
- Aging/drug effects
- Rats, Sprague-Dawley
- Rats
- Benzimidazoles/pharmacology
- Benzimidazoles/therapeutic use
- Muscle Fibers, Fast-Twitch/drug effects
- Muscle Fibers, Fast-Twitch/metabolism
- Muscle Fibers, Fast-Twitch/pathology
- Muscle Fibers, Slow-Twitch/drug effects
- Muscle Fibers, Slow-Twitch/metabolism
- Muscle Fibers, Slow-Twitch/pathology
- Muscle Strength/drug effects
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Proto-Oncogene Proteins c-akt/metabolism
- Myostatin/metabolism
- Antioxidants/pharmacology
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Affiliation(s)
- Priyanka Prajapati
- Department of Pharmaceutical Sciences, School of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Vidya Vihar, Raebareli Road, Lucknow 226025, India
| | - Anand Kumar
- Department of Pharmaceutical Sciences, School of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Vidya Vihar, Raebareli Road, Lucknow 226025, India
| | - Shubhada Mangrulkar
- Department of Pharmacology, Smt. Kishoritai Bhoyar College of Pharmacy, Kamptee, Nagpur 441002, India
| | - D R Chaple
- Priyadarshini J.L. College of Pharmacy, Electronic Zone Building, MIDC Hingna Road, Nagpur 440016, India
| | - Shubhini A Saraf
- National Institute of Pharmaceutical Education & Research, Raebareli (NIPER-R), Near CRPF Base Camp, Sarojini Nagar, Lucknow 226002, India
| | - Sapana Kushwaha
- National Institute of Pharmaceutical Education & Research, Raebareli (NIPER-R), Near CRPF Base Camp, Sarojini Nagar, Lucknow 226002, India
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Rohilla M, Rishabh, Bansal S, Garg A, Dhiman S, Dhankhar S, Saini M, Chauhan S, Alsubaie N, Batiha GES, Albezrah NKA, Singh TG. Discussing pathologic mechanisms of Diabetic retinopathy & therapeutic potentials of curcumin and β-glucogallin in the management of Diabetic retinopathy. Biomed Pharmacother 2023; 169:115881. [PMID: 37989030 DOI: 10.1016/j.biopha.2023.115881] [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: 07/30/2023] [Revised: 11/04/2023] [Accepted: 11/09/2023] [Indexed: 11/23/2023] Open
Abstract
Diabetic retinopathy (DR) is a form of retinal microangiopathy that occurs as a result of long-term Diabetes mellitus (DM). Patients with Diabetes mellitus typically suffer from DR as a progression of the disease that may be due to initiation and dysregulation of pathways like the polyol, hexosamine, the AGE/RAGE, and the PKC pathway, which all have negative impacts on eye health and vision. In this review, various databases, including PubMed, Google Scholar, Web of Science, and Science Direct, were scoured for data relevant to the aforementioned title. The three most common therapies for DR today are retinal photocoagulation, anti-vascular endothelial growth factor (VEGF) therapy, and vitrectomy, however, there are a number of drawbacks and limits to these methods. So, it is of critical importance and profound interest to discover treatments that may successfully address the pathogenesis of DR. Curcumin and β-glucogallin are the two potent compounds of natural origin that are already being used in various nutraceutical formulations for several ailments. They have been shown potent antiapoptotic, anti-inflammatory, antioxidant, anticancer, and pro-vascular function benefits in animal experiments. Their parent plant species have been used for generations by practitioners of traditional herbal medicine for the treatment and prevention of various eye ailments. In this review, we will discuss about pathophysiology of Diabetic retinopathy and the therapeutic potentials of curcumin and β-glucogallin one of the principal compounds from Curcuma longa and Emblica officinalis in Diabetic retinopathy.
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Affiliation(s)
- Manni Rohilla
- Chitkara College of Pharmacy, Chitkara University, Rajpura, Punjab 140401, India; Swami Vivekanand College of Pharmacy, Ram Nagar, Banur, Punjab 140601, India
| | - Rishabh
- M. M. College of Pharmacy, Maharishi Markandeshwar (Deemed to be University), Mullana, Ambala, Haryana 133207, India
| | - Seema Bansal
- M. M. College of Pharmacy, Maharishi Markandeshwar (Deemed to be University), Mullana, Ambala, Haryana 133207, India
| | - Anjali Garg
- Chitkara College of Pharmacy, Chitkara University, Rajpura, Punjab 140401, India; Swami Devi Dyal College of Pharmacy, Golpura Barwala, Panchkula, Haryana 134118, India
| | - Sachin Dhiman
- Chitkara College of Pharmacy, Chitkara University, Rajpura, Punjab 140401, India
| | - Sanchit Dhankhar
- Chitkara College of Pharmacy, Chitkara University, Rajpura, Punjab 140401, India
| | - Monika Saini
- Swami Vivekanand College of Pharmacy, Ram Nagar, Banur, Punjab 140601, India; M. M. College of Pharmacy, Maharishi Markandeshwar (Deemed to be University), Mullana, Ambala, Haryana 133207, India
| | - Samrat Chauhan
- Chitkara College of Pharmacy, Chitkara University, Rajpura, Punjab 140401, India.
| | - Nawal Alsubaie
- Department of Pharmacy Practice, College of Pharmacy, Princess Nourah Bint Abdulrahman University, P.O. Box 84428, Riyadh, Saudi Arabia
| | - Gaber El-Saber Batiha
- Department of Pharmacology and Therapeutics, Faculty of Veterinary Medicine, Damanhour University, Damanhour 22511, AlBeheira, Egypt
| | - Nisreen Khalid Aref Albezrah
- Obstetric and Gynecology Department, Medicine College, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia.
| | - Thakur Gurjeet Singh
- Chitkara College of Pharmacy, Chitkara University, Rajpura, Punjab 140401, India.
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3
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Gierke K, Lux UT, Regus-Leidig H, Brandstätter JH. The first synapse in vision in the aging mouse retina. Front Cell Neurosci 2023; 17:1291054. [PMID: 38026697 PMCID: PMC10654782 DOI: 10.3389/fncel.2023.1291054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 10/20/2023] [Indexed: 12/01/2023] Open
Abstract
Vision is our primary sense, and maintaining it throughout our lifespan is crucial for our well-being. However, the retina, which initiates vision, suffers from an age-related, irreversible functional decline. What causes this functional decline, and how it might be treated, is still unclear. Synapses are the functional hub for signal transmission between neurons, and studies have shown that aging is widely associated with synaptic dysfunction. In this study, we examined the first synapse of the visual system - the rod and cone photoreceptor ribbon synapse - in the mouse retina using light and electron microscopy at 2-3 months, ~1 year, and >2 years of age. We asked, whether age-related changes in key synaptic components might be a driver of synaptic dysfunction and ultimately age-related functional decline during normal aging. We found sprouting of horizontal and bipolar cells, formation of ectopic photoreceptor ribbon synapses, and a decrease in the number of rod photoreceptors and photoreceptor ribbon synapses in the aged retina. However, the majority of the photoreceptors did not show obvious changes in the structural components and protein composition of their ribbon synapses. Noteworthy is the increase in mitochondrial size in rod photoreceptor terminals in the aged retina.
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Affiliation(s)
| | | | | | - Johann Helmut Brandstätter
- Animal Physiology/Neurobiology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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Nag TC. Müller cell vulnerability in aging human retina: Implications on photoreceptor cell survival. Exp Eye Res 2023; 235:109645. [PMID: 37683797 DOI: 10.1016/j.exer.2023.109645] [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: 07/13/2023] [Revised: 08/29/2023] [Accepted: 09/05/2023] [Indexed: 09/10/2023]
Abstract
Müller glial cells (MC) support various metabolic functions of the retinal neurons, and maintain the homeostasis. Oxidative stress is intensified with aging, and in human retina, MC and photoreceptors undergo lipid peroxidation and protein nitration. Information on how MC respond to oxidative stress is vital to understand the fate of aging retinal neurons. This study examined age-related changes in MC of donor human retina (age: 35-98 years; N = 18 donors). Ultrastructural and immunohistochemical observations indicate that MC undergo gliosis and increased lipid peroxidation, and show osmotic changes with advanced aging (>80 years). Photoreceptor cells also undergo oxidative-nitrosative stress with aging, and their synapses also show clear osmotic swelling. MC respond to oxidative stress via proliferation of smooth endoplasmic reticulum in their processes, and increased expression of aquaporin-4 in endfeet and outer retina. In advanced aged retinas (81-98 years), they showed mitochondrial disorganisation, accumulation of lipids and autophagosomes, lipofuscin granules and axonal remnants in phagolysosomes in their inner processes, suggesting a reduced phagocytotic potential in them with aging. Glutamine synthetase expression does not alter until advanced aging, when the retinas show its increased expression in endfeet and Henle fiber layer. It is evident that MC are vulnerable with normal aging and this could be a reason for photoreceptor cell abnormalities reported with aging of the human retina.
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Affiliation(s)
- Tapas C Nag
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi, India.
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Prajapati P, Kumar A, Singh J, Saraf SA, Kushwaha S. Azilsartan Ameliorates Skeletal Muscle Wasting in High Fat Diet (HFD)-induced Sarcopenic Obesity in Rats via Activating Akt Signalling Pathway. Arch Gerontol Geriatr 2023; 112:105025. [PMID: 37062187 DOI: 10.1016/j.archger.2023.105025] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 03/26/2023] [Accepted: 04/10/2023] [Indexed: 04/18/2023]
Abstract
An association between the loss of skeletal muscle mass and obesity in the geriatric population has been identified as a disease known as sarcopenic obesity. Therefore, therapeutic/preventive interventions are needed to ameliorate sarcopenia. The present study investigates the effect of azilsartan (AZL) on skeletal muscle loss in High-Fat Diet (HFD)-induced sarcopenic obese (SO) rats. Four- and fourteen-months male Sprague Dawley rats were used and randomized in control and azilsartan treatment. 14 months animals were fed with HFD for four months and labeled as HFD-fed SO rats. Young & old rats received 0.5% carboxymethyl cellulose as a vehicle/AZL (8 mg/kg, per oral) treatment for six weeks. Grip strength and body composition analysis were performed after the last dose of AZL. Serum and gastrocnemius (GN)muscles were collected after animal sacrifice. AZL treatment significantly increased lean muscle mass, grip strength, myofibrillar protein, and antioxidant (superoxide dismutase & nitric oxide) levels in SO rats. AZL also restored the muscle biomarkers (creatine kinase, myostatin & testosterone), and insulin levels. AZL improves cellular, and ultracellular muscle structure and prevents type I to type II myofiber transitions in SO rats. Further, immunohistochemistry results showed increased expressions of pAkt and reduced expression of MuRF-1 and TNF-α exhibiting that AZL intervention could decrease protein degradation in SO rats. In conclusion, present results showed that AZL significantly increased lean mass, and restored muscle biomarkers, and muscle architecture. Taken together, the aforementioned findings suggest that azilsartan could be a possible therapeutic approach to reduce muscle wasting in sarcopenic obesity.
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Affiliation(s)
- Priyanka Prajapati
- Department of Pharmaceutical Sciences, School of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Vidya Vihar, Raebareli Road, Lucknow 226025, India
| | - Anand Kumar
- Department of Pharmaceutical Sciences, School of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Vidya Vihar, Raebareli Road, Lucknow 226025, India
| | - Jiten Singh
- Department of Pharmaceutical Sciences, Central University of Haryana, Jant-Pali, Mahendergarh, Haryana 123031, India
| | - Shubhini A Saraf
- Department of Pharmaceutical Sciences, School of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Vidya Vihar, Raebareli Road, Lucknow 226025, India
| | - Sapana Kushwaha
- National Institute of Pharmaceutical Education & Research, Raebareli (NIPER-R), New Transit campus, Bijnor-Sisendi Road, Near CRPF Base Camp, Sarojini Nagar, Lucknow 226002, India.
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6
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Albertos-Arranz H, Martínez-Gil N, Sánchez-Sáez X, Noailles A, Monferrer Adsuara C, Remolí Sargues L, Pérez-Santonja JJ, Lax P, Calvo Andrés R, Cuenca N. Microglia activation and neuronal alterations in retinas from COVID-19 patients: correlation with clinical parameters. EYE AND VISION (LONDON, ENGLAND) 2023; 10:12. [PMID: 36855168 PMCID: PMC9974399 DOI: 10.1186/s40662-023-00329-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 01/08/2023] [Indexed: 03/02/2023]
Abstract
BACKGROUND Different ocular alterations have been described in patients with coronavirus disease 2019 (COVID-19). Our aim was to determine whether COVID-19 affected retinal cells and establish correlations with clinical parameters. METHODS Retinal sections and flat-mount retinas from human donors with COVID-19 (n = 16) and controls (n = 15) were immunostained. The location of angiotensin-converting enzyme 2 (ACE2) and the morphology of microglial cells, Müller cells, astrocytes, and photoreceptors were analyzed by confocal microscopy. Microglial quantification and the area occupied by them were measured. Correlations among retinal and clinical parameters were calculated. RESULTS ACE2 was mainly located in the Müller cells, outer segment of cones and retinal pigment epithelium. Cell bodies of Müller cells in COVID-19 group showed greater staining of ACE2 and cellular retinaldehyde-binding protein (CRALBP). The 81.3% of COVID-19 patients presented disorganization of honeycomb-like pattern formed by Müller cells. Gliosis was detected in 56.3% of COVID-19 patients compared to controls (40%) as well as epiretinal membranes (ERMs) or astrocytes protruding (50%). Activated or ameboid-shape microglia was the main sign in the COVID-19 group (93.8%). Microglial migration towards the vessels was greater in the COVID-19 retinas (P < 0.05) and the area occupied by microglia was also reduced (P < 0.01) compared to control group. Cone degeneration was more severe in the COVID-19 group. Duration of the disease, age and respiratory failure were the most relevant clinical data in relation with retinal degeneration. CONCLUSIONS The retinas of patients with COVID-19 exhibit glial activation and neuronal alterations, mostly related to the inflammation, hypoxic conditions, and age.
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Affiliation(s)
- Henar Albertos-Arranz
- grid.5268.90000 0001 2168 1800Department of Physiology, Genetics and Microbiology, University of Alicante, San Vicente del Raspeig Road W/N, 03690 Alicante, Spain
| | - Natalia Martínez-Gil
- grid.5268.90000 0001 2168 1800Department of Physiology, Genetics and Microbiology, University of Alicante, San Vicente del Raspeig Road W/N, 03690 Alicante, Spain
| | - Xavier Sánchez-Sáez
- grid.5268.90000 0001 2168 1800Department of Physiology, Genetics and Microbiology, University of Alicante, San Vicente del Raspeig Road W/N, 03690 Alicante, Spain
| | - Agustina Noailles
- grid.5268.90000 0001 2168 1800Department of Physiology, Genetics and Microbiology, University of Alicante, San Vicente del Raspeig Road W/N, 03690 Alicante, Spain
| | - Clara Monferrer Adsuara
- grid.106023.60000 0004 1770 977XDepartment of Ophthalmology, General University Hospital Consortium of Valencia (CHGUV), 46014 Valencia, Spain
| | - Lidia Remolí Sargues
- grid.106023.60000 0004 1770 977XDepartment of Ophthalmology, General University Hospital Consortium of Valencia (CHGUV), 46014 Valencia, Spain
| | - Juan J. Pérez-Santonja
- grid.411086.a0000 0000 8875 8879Department of Ophthalmology, General University Hospital of Alicante (HGUA), 03010 Alicante, Spain ,grid.513062.30000 0004 8516 8274Alicante Institute for Health and Biomedical Research (ISABIAL), Alicante, Spain
| | - Pedro Lax
- grid.5268.90000 0001 2168 1800Department of Physiology, Genetics and Microbiology, University of Alicante, San Vicente del Raspeig Road W/N, 03690 Alicante, Spain
| | - Ramón Calvo Andrés
- grid.106023.60000 0004 1770 977XDepartment of Ophthalmology, General University Hospital Consortium of Valencia (CHGUV), 46014 Valencia, Spain
| | - Nicolás Cuenca
- Department of Physiology, Genetics and Microbiology, University of Alicante, San Vicente del Raspeig Road W/N, 03690, Alicante, Spain. .,Alicante Institute for Health and Biomedical Research (ISABIAL), Alicante, Spain. .,National Institute of Health Carlos III (ISCIII), (RETICS) Cooperative Health Network for Research in Ophthalmology (Oftared), 28040, Madrid, Spain.
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Pleiotropic Functions of Nitric Oxide Produced by Ascorbate for the Prevention and Mitigation of COVID-19: A Revaluation of Pauling's Vitamin C Therapy. Microorganisms 2023; 11:microorganisms11020397. [PMID: 36838362 PMCID: PMC9963342 DOI: 10.3390/microorganisms11020397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/30/2023] [Accepted: 01/31/2023] [Indexed: 02/08/2023] Open
Abstract
Linus Pauling, who was awarded the Nobel Prize in Chemistry, suggested that a high dose of vitamin C (l-ascorbic acid) might work as a prevention or treatment for the common cold. Vitamin C therapy was tested in clinical trials, but clear evidence was not found at that time. Although Pauling's proposal has been strongly criticized for a long time, vitamin C therapy has continued to be tested as a treatment for a variety of diseases, including coronavirus infectious disease 2019 (COVID-19). The pathogen of COVID-19, SARS-CoV-2, belongs to the β-coronavirus lineage, which includes human coronavirus, severe acute respiratory syndrome (SARS), and Middle East respiratory syndrome (MERS). This review intends to shed new light on vitamin C antiviral activity that may prevent SARS-CoV-2 infection through the chemical production of nitric oxide (NO). NO is a gaseous free radical that is largely produced by the enzyme NO synthase (NOS) in cells. NO produced by upper epidermal cells contributes to the inactivation of viruses and bacteria contained in air or aerosols. In addition to enzymatic production, NO can be generated by the chemical reduction of inorganic nitrite (NO2-), an alternative mechanism for NO production in living organisms. Dietary vitamin C, largely contained in fruits and vegetables, can reduce the nitrite in saliva to produce NO in the oral cavity when chewing foods. In the stomach, salivary nitrite can also be reduced to NO by vitamin C secreted from the epidermal cells of the stomach. The strong acidic pH of gastric juice facilitates the chemical reduction of salivary nitrite to produce NO. Vitamin C contributes in multiple ways to the host innate immune system as a first-line defense mechanism against pathogens. Highlighting chemical NO production by vitamin C, we suggest that controversies on the therapeutic effects of vitamin C in previous clinical trials may partly be due to less appreciation of the pleiotropic functions of vitamin C as a universal bioreductant.
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Arrigo A, Aragona E, Battaglia Parodi M, Bandello F. Quantitative approaches in multimodal fundus imaging: State of the art and future perspectives. Prog Retin Eye Res 2023; 92:101111. [PMID: 35933313 DOI: 10.1016/j.preteyeres.2022.101111] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 07/16/2022] [Accepted: 07/19/2022] [Indexed: 02/01/2023]
Abstract
When it first appeared, multimodal fundus imaging revolutionized the diagnostic workup and provided extremely useful new insights into the pathogenesis of fundus diseases. The recent addition of quantitative approaches has further expanded the amount of information that can be obtained. In spite of the growing interest in advanced quantitative metrics, the scientific community has not reached a stable consensus on repeatable, standardized quantitative techniques to process and analyze the images. Furthermore, imaging artifacts may considerably affect the processing and interpretation of quantitative data, potentially affecting their reliability. The aim of this survey is to provide a comprehensive summary of the main multimodal imaging techniques, covering their limitations as well as their strengths. We also offer a thorough analysis of current quantitative imaging metrics, looking into their technical features, limitations, and interpretation. In addition, we describe the main imaging artifacts and their potential impact on imaging quality and reliability. The prospect of increasing reliance on artificial intelligence-based analyses suggests there is a need to develop more sophisticated quantitative metrics and to improve imaging technologies, incorporating clear, standardized, post-processing procedures. These measures are becoming urgent if these analyses are to cross the threshold from a research context to real-life clinical practice.
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Affiliation(s)
- Alessandro Arrigo
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy.
| | - Emanuela Aragona
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy
| | - Maurizio Battaglia Parodi
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy
| | - Francesco Bandello
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy
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Nag TC. Immunohistochemical features of cells in peripheral microcystoid retinal degeneration. Acta Histochem 2022; 124:151893. [PMID: 35405413 DOI: 10.1016/j.acthis.2022.151893] [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: 11/04/2021] [Revised: 04/03/2022] [Accepted: 04/04/2022] [Indexed: 11/01/2022]
Abstract
Peripheral microcystoid retinal degeneration (PMD) is an age-related, benign condition in which the peripheral retina develops small holes and undergoes cystic degeneration. This paper demonstrates neuronal alterations in PMD, as studied by immunohistochemistry in postmortem donor eyes (age: 76-89 years; N = 6 donors). In all cases, the degeneration was located in the inferior temporal quadrant, creating holes in the far peripheral retina. There was thinning of the inner retinal layers and the outer plexiform layer (OPL) was patchy or inconspicuous. As a response, Müller cell processes showed increased vimentin immunoreactivity. None of the retinas examined expressed glial fibrillary acidic protein. Cone photoreceptor cells were significantly altered: compared to the adjoining cones that were short, those located in the cystoid retina underwent significant elongation of their inner segments, evident from calbindin immunolabeling, to maintain synaptic contacts with the remnant OPL. The latter consisted of small photoreceptor terminals and scanty processes from shrunken bipolar cells. Besides, cones and ganglion cells undergo oxidative stress, they showed immunoreactivity to 4-hydroxy 2-nonenal and nitrotyrosine. The level of superoxide dismutase-2 was relatively low in the PMD region than in adjacent area, suggesting that the former suffers from oxidative stress.
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10
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Nag TC, Gorla S, Kumari C, Roy TS. Aging of the human choriocapillaris: Evidence that early pericyte damage can trigger endothelial changes. Exp Eye Res 2021; 212:108771. [PMID: 34624336 DOI: 10.1016/j.exer.2021.108771] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 08/15/2021] [Accepted: 09/17/2021] [Indexed: 01/25/2023]
Abstract
The choriocapillaris (CC), the capillary bed in the choroid, essentially nourishes the photoreceptor cells. Its damage in aging and age-related diseases significantly influences the survival of the photoreceptor cells. Earlier reports implicated endothelial loss in aged and diseased CC; however, age-related pericyte changes and their contribution in CC death remain unknown. We examined human donor eyes (age: 56-94 years; N = 24), and found that CC pericyte damage preceded endothelial changes. With aging (>70 years), the sub-macular choroid accumulated debris in Bruch's membrane (BM). Of the debris content, the long-spaced collagens had a tendency to settle over the capillary basal lamina (BL), and this often resulted in endothelial projection into capillary lumen. Between 75 and 83 years, pericytes contained dark mitochondria, and their processes facing the BM debris showed partial loss of BL and intermediate filaments (IFs), when the endothelium remained unaltered. The endothelial changes appeared beyond 83 years, the abundance of IFs and autophagy reinforced their survival until late aging. TUNEL+ pericytes, and immunoreactivity to carboxymethyl lysine and 4-hydroxy 2-nonenal, but no nitro-tyrosine, was detected in aged CC walls. Iba-1+ dystrophic microglia were present in the vicinity of the CC. Our data indicate that (1) BM debris exerts pressure on the CC, leading to the damage of the capillary BL and pericyte processes (2) loss of IFs results in early pericyte destabilization (3) capillary wall undergoes lipid peroxidative and glycative damage, and (4) pericyte damage leads to late endothelial changes and ultimately CC loss. Future research should explore the normal ways of pericyte maintenance in the aging nervous system.
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Affiliation(s)
- Tapas Chandra Nag
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi, 110029, India.
| | - Shilpa Gorla
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Chiman Kumari
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Tara Sankar Roy
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi, 110029, India
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Huang HW, Yang CM, Yang CH. Fibroblast Growth Factor Type 1 Ameliorates High-Glucose-Induced Oxidative Stress and Neuroinflammation in Retinal Pigment Epithelial Cells and a Streptozotocin-Induced Diabetic Rat Model. Int J Mol Sci 2021; 22:ijms22137233. [PMID: 34281287 PMCID: PMC8267624 DOI: 10.3390/ijms22137233] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/26/2021] [Accepted: 06/30/2021] [Indexed: 01/20/2023] Open
Abstract
Diabetic retinopathy (DR) is a common complication of diabetes that causes severe visual impairment globally. The pathogenesis of DR is related to oxidative stress and chronic inflammation. The fibroblast growth factor type 1 (FGF-1) mitogen plays crucial roles in cell function, development, and metabolism. FGF-1 is involved in blood sugar regulation and exerts beneficial antioxidative and anti-inflammatory effects on various organ systems. This study investigated the antioxidative and anti-inflammatory neuroprotective effects of FGF-1 on high-glucose-induced retinal damage. The results revealed that FGF-1 treatment significantly reversed the harmful effects of oxidative stress and inflammatory mediators in retinal tissue in a streptozotocin-induced diabetic rat model. These protective effects were also observed in the in vitro model of retinal ARPE-19 cells exposed to a high-glucose condition. We demonstrated that FGF-1 attenuated p38 mitogen-activated protein kinase and nuclear factor-κB pathway activation under the high-glucose condition. Our results indicated that FGF-1 could effectively prevent retinal injury in diabetes. The findings of this study could be used to develop novel treatments for DR that aim to reduce the cascade of oxidative stress and inflammatory signals in neuroretinal tissue.
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Affiliation(s)
- Hsin-Wei Huang
- Department of Ophthalmology, Wan Fang Hospital, Taipei Medical University, No. 111, Sec. 3, Xinglong Rd., Taipei 11696, Taiwan;
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, No. 1, Jen Ai Road Sec. 1, Taipei 100, Taiwan
| | - Chung-May Yang
- Department of Ophthalmology, National Taiwan University Hospital, No. 7, Zhongshan South Road, Taipei 100, Taiwan;
- Department of Ophthalmology, College of Medicine, National Taiwan University, No. 1, Jen Ai Road, Sec. 1, Taipei 100, Taiwan
| | - Chang-Hao Yang
- Department of Ophthalmology, National Taiwan University Hospital, No. 7, Zhongshan South Road, Taipei 100, Taiwan;
- Department of Ophthalmology, College of Medicine, National Taiwan University, No. 1, Jen Ai Road, Sec. 1, Taipei 100, Taiwan
- Correspondence: ; Tel.: +886-2-2312-3456 (ext. 62131); Fax: +886-2-2393-4420
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12
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Pathogenic mechanisms contributing to the vulnerability of aging human photoreceptor cells. Eye (Lond) 2021; 35:2917-2929. [PMID: 34079093 DOI: 10.1038/s41433-021-01602-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 04/29/2021] [Accepted: 05/10/2021] [Indexed: 01/04/2023] Open
Abstract
In human retina, photoreceptor cell death (PCD) is a slow but conspicuous event, which continues with aging. Rods die earlier than cones, the latter continue to alter in a subtle manner until advanced aging. This review summarizes the existing information on age-related changes in photoreceptor cells, especially cones and analyses the possible associated factors. Oxidative and nitrosative stress are involved in photoreceptor alterations, which may stem from light and iron toxicity and other sources. Lipid peroxidation in macular photoreceptor outer segments and mitochondrial aberrations are prominent in aging. It is important to understand how those changes ultimately trigger PCD. The redistribution of calbindin D-28K and long/middle-wavelength-sensitive opsin in the parafoveal and perifoveal cones, anomalies in their somata and axons are strong predictors of their increasing vulnerability with aging. Signs of reduced autophagy, with autophagosomes containing organelle remnants are seen in aging photoreceptor cells. Currently, mechanisms that lead to human PCD are unknown; some observations favour apoptosis as a pathway. Since cones appear to change slowly, there is an opportunity to reverse those changes before they die. Therefore, a full understanding of how cones alter and the molecular pathways they utilize for survival must be the future research goal. Recent approaches to prevent PCD in aging and diseases are highlighted.
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Hou XW, Wang Y, Pan CW. Metabolomics in Age-Related Macular Degeneration: A Systematic Review. Invest Ophthalmol Vis Sci 2020; 61:13. [PMID: 33315052 PMCID: PMC7735950 DOI: 10.1167/iovs.61.14.13] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 11/25/2020] [Indexed: 12/22/2022] Open
Abstract
Purpose Age-related macular degeneration (AMD) is one of the leading causes of blindness among the elderly, and the exact pathogenesis of the AMD remains unclear. The purpose of this review is to summarize potential metabolic biomarkers and pathways of AMD that might facilitate risk predictions and clinical diagnoses of AMD. Methods We obtained relevant publications of metabolomics studies of human beings by systematically searching the MEDLINE (PubMed) database before June 2020. Studies were included if they performed mass spectrometry-based or nuclear magnetic resonance-based metabolomics approach for humans. In addition, AMD was assessed from fundus photographs based on standardized protocols. The metabolic pathway analysis was performed using MetaboAnalyst 3.0. Results Thirteen studies were included in this review. Repeatedly identified metabolites including phenylalanine, adenosine, hypoxanthine, tyrosine, creatine, citrate, carnitine, proline, and maltose have the possibility of being biomarkers of AMD. Validation of the biomarker panels was observed in one study. Dysregulation of metabolic pathways involves lipid metabolism, carbohydrate metabolism, nucleotide metabolism, amino acid metabolism, and translation, which might play important roles in the development and progression of AMD. Conclusions This review summarizes the potential metabolic biomarkers and pathways related to AMD, providing opportunities for the construction of diagnostic or predictive models for AMD and the discovery of new therapeutic targets.
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Affiliation(s)
- Xiao-Wen Hou
- School of Public Health, Medical College of Soochow University, Suzhou, China
| | - Ying Wang
- School of Public Health, Medical College of Soochow University, Suzhou, China
| | - Chen-Wei Pan
- School of Public Health, Medical College of Soochow University, Suzhou, China
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Nag TC, Kathpalia P, Wadhwa S. Microtubule alterations may destabilize photoreceptor integrity: Age-related microtubule changes and pattern of expression of MAP-2, Tau and hyperphosphorylated Tau in aging human photoreceptor cells. Exp Eye Res 2020; 198:108153. [PMID: 32710889 DOI: 10.1016/j.exer.2020.108153] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Revised: 06/15/2020] [Accepted: 07/15/2020] [Indexed: 11/28/2022]
Abstract
Photoreceptor cells undergo changes with aging. It is unknown if their microtubules are stable or not with aging. This study examined photoreceptor cell ultrastructure from 18 human donor retinas (32 eyes; age: 45-94 years) and quantified the photoreceptors with altered microtubules over six to ninth decades in four defined retinal regions. In addition, immunoreactivity (IR) to microtubule-associated protein-2 (MAP-2), tau and hyperphophorylated tau was performed in retinal sections from companion eyes. In young donor retinas below 75 years of age, microtubules appeared straight in photoreceptor inner segments and axons. With age, they appeared bent or misaligned in macular and mid-peripheral photoreceptors. In addition, dense granular materials were present in photoreceptor axons and synaptic terminals in advanced ages. In all decades, rod microtubules were affected more than their cone counterparts (28% vs 15%, p < 0.005). Both rods and cones were significantly affected in mid-peripheral retina (5-8 mm outside the macular border) in eighth decade, compared to other decades or retinal regions (parafoveal, perifoveal and nasal) examined (p < 0.005). IR showed a steady expression of MAP-2 in inner segments, and tau in inner segments to axons below 75 years of age, but was absent for both markers in scattered macular and mid-peripheral photoreceptors in advanced ages (>75 years). IR to hyperphosphorylated tau was present mainly in inner retina and increased with aging. Markers of oxidative stress, e.g., lipid peroxidation (4-hydroxy 2-nonenal) and nitrosative stress (nitrotyrosine) were immunopositive in aged photoreceptors. The sporadic loss of MAP-2 and tau-IR in photoreceptors may be due to microtubule changes; all these changes may affect intracellular transport and be partly responsible for photoreceptor death in aged human retina.
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Affiliation(s)
- Tapas C Nag
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi, India.
| | - Poorti Kathpalia
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi, India
| | - Shashi Wadhwa
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi, India
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15
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Alves CH, Fernandes R, Santiago AR, Ambrósio AF. Microglia Contribution to the Regulation of the Retinal and Choroidal Vasculature in Age-Related Macular Degeneration. Cells 2020; 9:cells9051217. [PMID: 32423062 PMCID: PMC7290930 DOI: 10.3390/cells9051217] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 05/09/2020] [Accepted: 05/12/2020] [Indexed: 12/17/2022] Open
Abstract
The retina is a highly metabolically active tissue with high-level consumption of nutrients and oxygen. This high metabolic demand requires a properly developed and maintained vascular system. The retina is nourished by two systems: the central retinal artery that supplies the inner retina and the choriocapillaris that supplies the outer retina and retinal pigment epithelium (RPE). Pathological neovascularization, characterized by endothelial cell proliferation and new vessel formation, is a common hallmark in several retinal degenerative diseases, including age-related macular degeneration (AMD). A limited number of studies have suggested that microglia, the resident immune cells of the retina, have an important role not only in the pathology but also in the formation and physiology of the retinal vascular system. Here, we review the current knowledge on microglial interaction with the retinal vascular system under physiological and pathological conditions. To do so, we first highlight the role of microglial cells in the formation and maintenance of the retinal vasculature system. Thereafter, we discuss the molecular signaling mechanisms through which microglial cells contribute to the alterations in retinal and choroidal vasculatures and to the neovascularization in AMD.
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Affiliation(s)
- C. Henrique Alves
- Retinal Dysfunction and Neuroinflammation Lab, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (C.H.A.); (R.F.); (A.R.S.)
- Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3004-531 Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image (AIBILI), 3000-548 Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), 3004-561 Coimbra, Portugal
| | - Rosa Fernandes
- Retinal Dysfunction and Neuroinflammation Lab, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (C.H.A.); (R.F.); (A.R.S.)
- Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3004-531 Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image (AIBILI), 3000-548 Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), 3004-561 Coimbra, Portugal
| | - Ana Raquel Santiago
- Retinal Dysfunction and Neuroinflammation Lab, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (C.H.A.); (R.F.); (A.R.S.)
- Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3004-531 Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image (AIBILI), 3000-548 Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), 3004-561 Coimbra, Portugal
| | - António Francisco Ambrósio
- Retinal Dysfunction and Neuroinflammation Lab, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (C.H.A.); (R.F.); (A.R.S.)
- Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3004-531 Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image (AIBILI), 3000-548 Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), 3004-561 Coimbra, Portugal
- Correspondence: ; Tel.: +351-239-480093
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Eamegdool SS, Sitiwin EI, Cioanca AV, Madigan MC. Extracellular matrix and oxidative stress regulate human retinal pigment epithelium growth. Free Radic Biol Med 2020; 146:357-371. [PMID: 31751761 DOI: 10.1016/j.freeradbiomed.2019.11.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Revised: 11/01/2019] [Accepted: 11/13/2019] [Indexed: 11/23/2022]
Abstract
Age-related macular degeneration (AMD), the most common cause of vision loss with ageing, is characterised by degeneration of the photoreceptors and retinal pigment epithelium (RPE) and changes in the extracellular matrix (ECM) underlying the RPE. The pathogenesis of AMD is still not fully understood. In this study we investigated the in vitro growth and function of primary human RPE cells in response to different ECM substrates, including nitrite-modified ECM. We initially confirmed the presence of disorganised retinal glial and photoreceptor cells, marked retinal cytoplasmic and Bruch's membrane expression of nitro-tyrosine (an oxidative stress marker) and increased numbers of Iba1+ macrophages/microglia in human donor eye sections (aged and AMD) using multi-marker immunohistochemistry (n = 3). Concurrently, we utilised two-photon microscopy to reveal topographical changes in flatmounts of RPE-associated ECM and in the underlying choroid of aged and AMD donor eyes (n = 3). To recapitulate these observations in vitro, we then used primary human RPE cells to investigate how different ECM proteins, including nitrite cross-linked RPE-secreted ECM, modified RPE cell growth and function. Collagen I or IV increased RPE attachment and spreading two-to three-fold, associated with significantly increased cell migration and proliferation, consistent with a preferential interaction with these matrix substrates. Primary human RPE cells grown on collagen I and IV also showed increased secretion of pro-inflammatory cytokines, MCP-1 and IL-8. Nitrite-modification of RPE-secreted ECM (simulating ageing of Bruch's membrane) significantly reduced in vitro RPE attachment to the ECM and this was mitigated with collagen IV coating of the modified ECM. Taken together, our observations confirm the importance of RPE-ECM interactions for normal RPE growth and function, and for inducing RPE secretion of pro-inflammatory cytokines. Furthermore, the findings are consistent with ageing and/or oxidative stress-induced disruption of RPE-ECM interactions contributing to the pathogenesis of AMD.
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Affiliation(s)
- Steven S Eamegdool
- Save Sight Institute, University of Sydney, 2000, Australia; Eye Genetics Research Unit, Children's Medical Research Institute, 2145, Australia.
| | - Ephrem I Sitiwin
- Save Sight Institute, University of Sydney, 2000, Australia; School of Optometry and Vision Science, UNSW, 2052, Australia; Biomedical Imaging Facility, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Adrian V Cioanca
- Save Sight Institute, University of Sydney, 2000, Australia; The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, 2601, Australia.
| | - Michele C Madigan
- Save Sight Institute, University of Sydney, 2000, Australia; School of Optometry and Vision Science, UNSW, 2052, Australia.
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Nag TC, Maurya M, Roy TS. Age-related changes of the human retinal vessels: Possible involvement of lipid peroxidation. Ann Anat 2019; 226:35-47. [PMID: 31330304 DOI: 10.1016/j.aanat.2019.06.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Revised: 06/28/2019] [Accepted: 06/29/2019] [Indexed: 12/20/2022]
Abstract
BACKGROUND Aging of the human retina is accompanied by oxidative stress that exerts profound changes in the retinal neurons. It is unknown if oxidative stress influences the cellular components of the retinal vessels in some ways. METHODS We examined changes in retinal vessels in human donor eyes (age: 35-94 years; N=18) by light and transmission electron microscopy, TUNEL and immunohistochemistry for biomarkers of vascular smooth muscle cells (SMC; actin), oxidative stress (4-hydroxy 2-nonenal [HNE] and nitrotyrosine), microglia (Iba-1) and vessels (isolectin B4). RESULTS The earliest changes in the endothelium and pericytes of capillaries are apparent from the seventh decade. With aging, there is clear loss of organelles and cytoplasmic filaments, and a progressive thickening of the endothelial and pericyte basal lamina. Loss of filaments, accumulation of lipofuscin and autophagic vacuoles are significant events in aging pericytes and SMC. Actin immunolabelling reveals discontinuity in arterial SMC layers during eighth decade, indicating partial degeneration of SMC. This is followed by hyalinization, with degeneration of the endothelium and SMC in arteries and arterioles of the nerve fibre layer (NFL) and ganglion cell layer in ninth decade. Iba-1 positive microglia were in close contact with the damaged vessels in inner retina, and their cytoplasm was rich in lysosomes. HNE immunoreactivity, but not of nitrotyrosine, was detected in aged vessels from seventh decade onwards, suggesting that lipid peroxidation is a major problem of aged vessels. However, TUNEL positivity seen during this period was limited to few arteries and venules of NFL. CONCLUSION This study shows prominent age-related alterations of the pericytes and SMC of retinal vessels. These changes may limit the energy supply to the neurons and be responsible for age-related loss of neurons of the inner retina.
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Affiliation(s)
- Tapas Chandra Nag
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi 110029, India.
| | - Meenakshi Maurya
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Tara Sankar Roy
- Department of Anatomy, All India Institute of Medical Sciences, New Delhi 110029, India
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