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Zuo Z, Zhang Z, Zhang S, Fan B, Li G. The Molecular Mechanisms Involved in Axonal Degeneration and Retrograde Retinal Ganglion Cell Death. DNA Cell Biol 2023; 42:653-667. [PMID: 37819746 DOI: 10.1089/dna.2023.0180] [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: 10/13/2023] Open
Abstract
Axonal degeneration is a pathologic change common to multiple retinopathies and optic neuropathies. Various pathologic factors, such as mechanical injury, inflammation, and ischemia, can damage retinal ganglion cell (RGC) somas and axons, eventually triggering axonal degeneration and RGC death. The molecular mechanisms of somal and axonal degeneration are distinct but also overlap, and axonal degeneration can result in retrograde somal degeneration. While the mitogen-activated protein kinase pathway acts as a central node in RGC axon degeneration, several newly discovered molecules, such as sterile alpha and Toll/interleukin-1 receptor motif-containing protein 1 and nicotinamide mononucleotide adenylyltransferase 2, also play a critical role in this pathological process following different types of injury. Therefore, we summarize the types of injury that cause RGC axon degeneration and retrograde RGC death and important underlying molecular mechanisms, providing a reference for the identification of targets for protecting axons and RGCs.
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Affiliation(s)
- Zhaoyang Zuo
- Department of Ophthalmology, Second Hospital of Jilin University, Changchun, China
| | - Ziyuan Zhang
- Department of Ophthalmology, Second Hospital of Jilin University, Changchun, China
| | - Siming Zhang
- Department of Ophthalmology, Second Hospital of Jilin University, Changchun, China
| | - Bin Fan
- Department of Ophthalmology, Second Hospital of Jilin University, Changchun, China
| | - Guangyu Li
- Department of Ophthalmology, Second Hospital of Jilin University, Changchun, China
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Guo Y, Ou C, Zhang N, Liu Q, Xiong K, Yu J, Cheng H, Chen L, Ma M, Xu J, Wu J. Roflumilast attenuates neuroinflammation post retinal ischemia/reperfusion injury by regulating microglia phenotype via the Nrf2/STING/NF-κB pathway. Int Immunopharmacol 2023; 124:110952. [PMID: 37751655 DOI: 10.1016/j.intimp.2023.110952] [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: 06/23/2023] [Revised: 09/11/2023] [Accepted: 09/13/2023] [Indexed: 09/28/2023]
Abstract
PURPOSE The abnormal polarisation of microglial cells (MGs) following retinal ischemia/reperfusion (RIR) initiates neuroinflammation and progressive death of retinal ganglion cells (RGCs), causing increasingly severe and irreversible visual dysfunction. Roflumilast (Roflu) is a promising candidate for treating neuroinflammatory diseases. This study aimed to explore whether Roflu displayed a cytoprotective effect against RIR-induced neuroinflammation and to characterise the underlying signalling pathway. METHODS The effects and mechanism of Roflu against RIR injury were investigated in C57BL/6J mice and the BV2 cell line. We used quantitative real-time PCR and enzyme-linked immunosorbent assay to examine the levels of inflammatory factors. Furthermore, haematoxylin and eosin and immunofluorescence (IF) stainings were used to assess the morphology of the retina and the states of MGs and RGCs. Reactive oxygen species (ROS) levels were examined using a ROS assay kit, while whole-genome sequencing analysis was conducted to identify altered pathways and molecules. Western blotting and IF staining were used to quantify the proteins associated with the nuclear factor erythroid 2-related factor 2 (Nrf2)/stimulator of interferon gene (STING)/nuclear factor kappa beta (NF-κB) pathway. RESULTS MG polarisation includes the pro-inflammatory and neurotoxic M1 phenotype as well as the anti-inflammatory and neuroprotective M2 phenotype. Roflu significantly attenuated MG activation and contributed to a shift in the MG phenotype from M1 to M2. Moreover, Roflu decreased ROS release and increased heme oxygenase 1 and NAD(P)H quinone oxidoreductase 1 expression. In vitro and in vivo experiments validated that Roflu exerted its neuroprotective effects primarily by upregulating the Nrf2/STING/NF-κB pathway. However, these effects were abrogated when the Nrf2 expression was inhibited by pharmacological or genetic manipulation. CONCLUSIONS Roflu suppressed RIR-induced neuroinflammation by driving the shift of MG polarisation from M1 to M2 phenotype, which was mediated by the upregulation of the Nrf2/STING/NK-κB pathway.
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Affiliation(s)
- Yuyan Guo
- Department of Ophthalmology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China; Department of Ophthalmology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510120, Guangdong, China
| | - Chunlian Ou
- Department of General Practice, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Naiyuan Zhang
- Department of Ophthalmology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Qiong Liu
- Department of Ophthalmology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Ke Xiong
- Department of Ophthalmology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Jian Yu
- Department of Ophthalmology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Hao Cheng
- Department of Ophthalmology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510120, Guangdong, China
| | - Linjiang Chen
- Department of Ophthalmology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Ming Ma
- Department of Ophthalmology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Jing Xu
- Department of Ophthalmology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China.
| | - Jing Wu
- Huiqiao Medical Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China.
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Zeng S, Du L, Lu G, Xing Y. CREG Protects Retinal Ganglion Cells loss and Retinal Function Impairment Against ischemia-reperfusion Injury in mice via Akt Signaling Pathway. Mol Neurobiol 2023; 60:6018-6028. [PMID: 37402034 DOI: 10.1007/s12035-023-03466-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 06/24/2023] [Indexed: 07/05/2023]
Abstract
PURPOSE The irreversible death of retinal ganglion cells (RGCs) plays an important role in the pathogenesis of glaucoma. Cellular repressor of E1A-stimulated genes (CREG), a secreted glycoprotein involved in cellular proliferation and differentiation, has been shown to protect against myocardial and renal ischemia-reperfusion damage. However, the role of CREG in retinal ischemia-reperfusion injury (RIRI) remains unknown. In this study, we aimed to explore the effect of CREG on RGCs apoptosis after RIRI. METHODS We used male C57BL/6J mice to establish the RIRI model. Recombinant CREG was injected at 1 day before RIRI. The expression and distribution of CREG were examined by immunofluorescence staining and western blotting. RGCs survival was assessed by immunofluorescence staining of flat-mounted retinas. Retinal apoptosis was measured by the staining of TdT-mediated dUTP nick-end labeling and cleaved caspase-3. Electroretinogram (ERG) analysis and optomotor response were conducted to evaluate retinal function and visual acuity. The expressions of Akt, phospho-Akt (p-Akt), Bax, and Bcl-2 were analyzed by western blotting to determine the signaling pathways of CREG. RESULTS We found that CREG expression was decreased after RIRI, and intravitreal injection of CREG attenuated RGCs loss and retinal apoptosis. Besides, the amplitudes of a-wave, b-wave, and photopic negative response (PhNR) in ERG, as well as visual function, were significantly restored after treatment with CERG. Furthermore, intravitreal injection of CREG upregulated p-Akt and Bcl-2 expression and downregulated Bax expression. CONCLUSION Our results demonstrated that CREG protected RGCs from RIRI and alleviated retinal apoptosis by activating Akt signaling. In addition, CREG also improved retinal function and visual acuity.
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Affiliation(s)
- Siyu Zeng
- Eye Center, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, 430060, Hubei Province, People's Republic of China
| | - Lei Du
- Eye Center, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, 430060, Hubei Province, People's Republic of China
| | - Guojing Lu
- Eye Center, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, 430060, Hubei Province, People's Republic of China
| | - Yiqiao Xing
- Eye Center, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuhan, 430060, Hubei Province, People's Republic of China.
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Murenu E, Gerhardt MJ, Biel M, Michalakis S. More than meets the eye: The role of microglia in healthy and diseased retina. Front Immunol 2022; 13:1006897. [PMID: 36524119 PMCID: PMC9745050 DOI: 10.3389/fimmu.2022.1006897] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 11/11/2022] [Indexed: 11/30/2022] Open
Abstract
Microglia are the main resident immune cells of the nervous system and as such they are involved in multiple roles ranging from tissue homeostasis to response to insults and circuit refinement. While most knowledge about microglia comes from brain studies, some mechanisms have been confirmed for microglia cells in the retina, the light-sensing compartment of the eye responsible for initial processing of visual information. However, several key pieces of this puzzle are still unaccounted for, as the characterization of retinal microglia has long been hindered by the reduced population size within the retina as well as the previous lack of technologies enabling single-cell analyses. Accumulating evidence indicates that the same cell type may harbor a high degree of transcriptional, morphological and functional differences depending on its location within the central nervous system. Thus, studying the roles and signatures adopted specifically by microglia in the retina has become increasingly important. Here, we review the current understanding of retinal microglia cells in physiology and in disease, with particular emphasis on newly discovered mechanisms and future research directions.
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Affiliation(s)
- Elisa Murenu
- Department of Ophthalmology, Klinikum der Ludwig-Maximilians-Universität München, Munich, Germany,*Correspondence: Elisa Murenu, ; ; Stylianos Michalakis,
| | | | - Martin Biel
- Department of Pharmacy, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Stylianos Michalakis
- Department of Ophthalmology, Klinikum der Ludwig-Maximilians-Universität München, Munich, Germany,*Correspondence: Elisa Murenu, ; ; Stylianos Michalakis,
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Zeng Y, Wen F, Mi L, Ji Y, Zhang X. Changes in macrophage-like cells characterized by en face optical coherence tomography after retinal stroke. Front Immunol 2022; 13:987836. [PMID: 36177000 PMCID: PMC9514656 DOI: 10.3389/fimmu.2022.987836] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 08/29/2022] [Indexed: 11/15/2022] Open
Abstract
Purpose The retina could serve as a window of neuroinflammation, but the in vivo changes in macrophage-like cell (MLC), such as microglia, in acute ischemic retinal stroke remain unclear. Thus, the current study aimed to investigate the in vivo changes in MLC characterized by en face optical coherence tomography (OCT) after acute ischemic retinal stroke. Methods Twenty patients with unilateral acute nonarteritic reperfused central retinal artery occlusion (CRAO) were participated in this study, and their contralateral eyes served as control group. A 3 μm en face OCT slab on the inner limiting membrane of the optic nerve head (ONH) region or macular region was used to visualize and binarize the MLCs. The MLCs were binarized and quantified using a semiautomated method. OCT angiography was used to evaluate the reperfusion status and obtain the structural data of the inner retina in the ONH and macula. The thickness of the ganglion cell complex in the macular region was measured. The optical intensity and optical intensity ratio of the inner retina were calculated to evaluate the ischemia severity. Results In the ONH region, decreased vessel densities of radial peripapillary capillaries accompanied by increased thickness of the retinal nerve fiber layer were found in the CRAO eyes in comparison to the unaffected eyes (p=0.001, p=0.009, respectively). In the macular region, significantly lower vessel densities in both the superficial and deep capillary plexus and increased thickness of the ganglion cell complex were also found in the CRAO eyes (all p ≤ 0.001). The ONH and macular MLC quantities and densities in CRAO eyes were significantly higher than those in the unaffected eyes (both p<0.001). Larger and plumper MLCs were observed in the CRAO eyes compared with their unaffected eyes. ONH and macular MLC densities were positively associated with the disease duration in the acute phase and the optical intensity ratio of inner retina. Conclusions The increased density and morphological changes of MLCs may indicate the aggregation and activation of MLCs following acute reperfused CRAO. The aggregation of MLCs may be more pronounced in CRAO eyes with longer disease duration and more severe ischemia. MLCs characterized by en face OCT may serve as an in vivo visual tool to investigate neuroinflammation in the ischemic-reperfusion process of stroke.
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Lu P, Shi Y, Ye D, Lu X, Tang X, Cheng L, Xu Y, Huang J. Intravitreal Injection of PACAP Attenuates Acute Ocular Hypertension-Induced Retinal Injury Via Anti-Apoptosis and Anti-Inflammation in Mice. Invest Ophthalmol Vis Sci 2022; 63:18. [PMID: 35293951 PMCID: PMC8944396 DOI: 10.1167/iovs.63.3.18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Purpose Pituitary adenylate cyclase-activating polypeptide (PACAP) has shown potent neuroprotective effects in central nervous system and retina disorders. However, whether PACAP can attenuate retinal neurodegeneration induced by acute ocular hypertension (AOH) and the underlying mechanisms remain unknown. In this study, we aimed to investigate the effects of PACAP on the survival and function of retinal ganglion cells (RGCs), apoptosis, and inflammation in a mouse model of AOH injury. Methods PACAP was injected into the vitreous body immediately after inducing AOH injury. Hematoxylin and eosin staining and optical coherence tomography were used to evaluate the loss of retina tissue. Pattern electroretinogram was used to evaluate the function of RGCs. TUNEL assay was used to detect apoptosis. Immunofluorescence and western blot were employed to evaluate protein expression levels. Results PACAP treatment significantly reduced the losses of whole retina and inner retina thicknesses, Tuj1-positive RGCs, and the amplitudes of pattern electroretinograms induced by AOH injury. Additionally, PACAP treatment remarkably reduced the number of TUNEL-positive cells and inhibited the upregulation of Bim, Bax, and cleaved caspase-3 and downregulation of Bcl-xL after AOH injury. Moreover, PACAP markedly inhibited retinal reactive gliosis and vascular inflammation, as demonstrated by the downregulation of GFAP, Iba1, CD68, and CD45 in PACAP-treated mice. Furthermore, upregulated expression of NF-κB and phosphorylated NF-κB induced by AOH injury was attenuated by PACAP treatment. Conclusions PACAP could prevent the loss of retinal tissue and improve the survival and function of RGCs. The neuroprotective effect of PACAP is probably associated with its potent anti-apoptotic and anti-inflammatory effects.
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Affiliation(s)
- Peng Lu
- From the State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yuxun Shi
- From the State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Dan Ye
- From the 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
- From the 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
- From the State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Lu Cheng
- From the 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
- From the State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Jingjing Huang
- From the 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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Zhang QL, Wang JH, Sun LY, Wang JB, Ma Y, Zhang YQ. Optical Coherence Tomography Angiography Predicts Visual Outcomes for Craniopharyngioma in Children by Quantifying Choroidal Capillaries. Front Med (Lausanne) 2022; 8:819662. [PMID: 35096911 PMCID: PMC8790536 DOI: 10.3389/fmed.2021.819662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 12/08/2021] [Indexed: 11/13/2022] Open
Abstract
Purpose: To predict the prognosis of craniopharyngioma in children by optical coherence tomography angiography (OCTA). Methods: We evaluated if the relationship between preoperative OCTA of the choroidal capillary density (CCD) and visual outcome continued over long-term visual recovery in 38 patients undergoing craniopharyngioma resection. Patients were evaluated 3 times: 1 week before surgery (Visit1), followed-up at 6–10 weeks (Visit2), and 9–15 months (Visit3) after surgery. Results: In total 38 patients (70 eyes) with craniopharyngiomas, which included 20 (52.6%) boys and 18 (47.4%)girls, the mean age was 11.8 ± 2.7 years (range: 6–18 years). The age (p = 0.71), gender (p = 1.00), mean refractive error (p = 0.55), and axial length (p = 0.23) of 38 normal volunteers (76 eyes) were matched. After surgery, the cross-compression of patients was relieved. The average visual acuity change in the normal CCD group was 0.07 ± 0.02; the average visual acuity change in the low CCD group was 0.01 ± 0.01, p < 0.001. Preoperative CCD value is related to the preoperative BCVA (p < 0.001), and the visual function after the long-term follow-up (9–15 months) (p < 0.001). The prognosis of CCD has the same trend as the BCVA. Further correlation analysis shows that CCD and BCVA are significantly correlated (r = 0.878; p < 0.001). CCD has a weak but significant correlation both with MD (r = 0.19; p < 0.001) and PSD (r = −0.21; p <0.001). A natural cutoff of CCD is approximately 38%. With the normal CCD group the maximum improvement of BCVA exceeds 0.3 post-operatively, compared to eyes in the low CCD group that improve by <0.03, and worse after surgery. Conclusions: Long-term vision recovery after surgical decompression of craniopharyngiomas in children can be predicted by preoperative by OCTA. Patients with normal CCD before surgery showed a tendency to improve vision; this trend of improvement persisted in subsequent follow-ups. The CCD baseline natural cutoff value for predicting visual prognosis before and after surgery is about 38%.
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Affiliation(s)
- Qing Lin Zhang
- Department of Neurosurgery, Tsinghua University Yuquan Hospital, Beijing, China
| | - Jun Hua Wang
- Department of Neurosurgery, Tsinghua University Yuquan Hospital, Beijing, China
| | - Li Ying Sun
- Department of Neurosurgery, Tsinghua University Yuquan Hospital, Beijing, China
| | - Jian Bin Wang
- Department of Neurosurgery, Tsinghua University Yuquan Hospital, Beijing, China
| | - Yu Ma
- Department of Neurosurgery, Tsinghua University Yuquan Hospital, Beijing, China
| | - Yu Qi Zhang
- Department of Neurosurgery, Tsinghua University Yuquan Hospital, Beijing, China
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Kalloniatis M, Wang H, Katalinic P, Ly A, Apel W, Nivison-Smith L, Kalloniatis KF. Ocular ischaemia: signs, symptoms, and clinical considerations for primary eye care practitioners. Clin Exp Optom 2022; 105:117-134. [PMID: 34982952 DOI: 10.1080/08164622.2021.1999771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Ischaemic stroke is a major disease burden as well as a leading cause of death. Early signs of ischaemic stroke can manifest in the eye, placing primary eyecare practitioners in an important position to identify patients at risk of ischaemic stroke and initiate suitable referral pathways. The vascular supply to the brain is reviewed with reference to vision including the various retinal signs and ocular symptoms associated with transient ischaemic attacks and ischaemic stroke. Using a range of clinical cases, the diverse clinical presentations of retinal embolic events, as well as other forms of vascular occlusion, are highlighted and the underlying pathophysiology is discussed. A succinct scheme for the assessment and management of ischaemic events for primary eye care practitioners is provided.
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Affiliation(s)
- Michael Kalloniatis
- Centre for Eye Health, the University of New South Wales, Sydney, Australia.,School of Optometry and Vision Science, The University of New South Wales, Sydney, Australia
| | - Henrietta Wang
- Centre for Eye Health, the University of New South Wales, Sydney, Australia.,School of Optometry and Vision Science, The University of New South Wales, Sydney, Australia
| | - Paula Katalinic
- Centre for Eye Health, the University of New South Wales, Sydney, Australia.,School of Optometry and Vision Science, The University of New South Wales, Sydney, Australia
| | - Angelica Ly
- Centre for Eye Health, the University of New South Wales, Sydney, Australia.,School of Optometry and Vision Science, The University of New South Wales, Sydney, Australia
| | - Warren Apel
- Centre for Eye Health, the University of New South Wales, Sydney, Australia.,The Eye Health Centre, Aspley, Australia
| | - Lisa Nivison-Smith
- Centre for Eye Health, the University of New South Wales, Sydney, Australia.,School of Optometry and Vision Science, The University of New South Wales, Sydney, Australia
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Keilhoff G, Titze M, Ebmeyer U. Immuno-histological detection of resistant columnar units and vulnerable networks in the rat retina after asphyxia-induced transient cardiac arrest. Restor Neurol Neurosci 2021; 39:267-289. [PMID: 34334436 DOI: 10.3233/rnn-211174] [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: 12/25/2022]
Abstract
BACKGROUND Stroke-related loss of vision is one of the residual impairments, restricting the quality of life. However, studies of the ocular manifestations of asphyxia cardiac arrest/resuscitation (ACA/R) have reported very heterogeneous results. OBJECTIVE We aimed to evaluate the ACA/R-induced degeneration pattern of the different retinal cell populations in rats using different immuno-histological stainings. METHODS The staining pattern of toluidine blue and the ganglion cell markers β-III-tubulin and NeuN; the calcium-binding protein parvalbumin, indicating ganglion, amacrine, and horizontal cells; calretinin D28k, indicating ganglion and amacrine cells; calbindin, indicating horizontal cells; Chx 10, indicating cone bipolar cells; PKCα, indicating ON-type rod bipolar cells; arrestin, indicating cones; and rhodopsin, a marker of rods, as well as the glial cell markers GFAP (indicating astroglia and Müller cells) and IBA1 (indicating microglia), were evaluated after survival times of 7 and 21 days in an ACA/R rat model. Moreover, quantitative morphological analysis of the optic nerve was performed. The ACA/R specimens were compared with those from sham-operated and completely naïve rats. RESULTS ACA/R-induced effects were: (i) a significant reduction of retinal thickness after long-term survival; (ii) ganglion cell degeneration, including their fiber network in the inner plexiform layer; (iii) degeneration of amacrine and cone bipolar cells; (iv) degeneration of cone photoreceptors; (v) enhanced resistance to ACA/R by rod photoreceptors, ON-type rod bipolar and horizontal cells, possibly caused by the strong upregulation of the calcium-binding proteins calretinin, parvalbumin, and calbindin, counteracting the detrimental calcium overload; (vi) significant activation of Müller cells as further element of retinal anti-stress self-defense mechanisms; and (vii) morphological alterations of the optic nerve in form of deformed fibers. CONCLUSIONS Regardless of the many defects, the surviving neuronal structures seemed to be able to maintain retinal functionality, which can be additionally improved by regenerative processes true to the "use it or lose it" dogma.
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Affiliation(s)
- Gerburg Keilhoff
- Institute of Biochemistry and Cell Biology, Medical Faculty, University of Magdeburg, Magdeburg, Germany
| | - Maximilian Titze
- Institute of Biochemistry and Cell Biology, Medical Faculty, University of Magdeburg, Magdeburg, Germany
| | - Uwe Ebmeyer
- Department of Anesthesiology, Medical Faculty, University of Magdeburg, Magdeburg, Germany
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