Ischemic optic neuropathy as a model of neurodegenerative disorder: A review of pathogenic mechanism of axonal degeneration and the role of neuroprotection

Protective effects of compound M01 on retinal ganglion cells in experimental anterior ischemic optic neuropathy by inhibiting TXNIP/NLRP3 inflammasome pathway

Apoptotic death of retinal ganglion cells (RGCs) is a common pathologic feature in different types of optic neuropathy, including ischemic optic neuropathy and glaucoma, ultimately leading to irreversible visual function loss. Potent and effective protection against RGC death is determinative in developing a successful treatment for these optic neuropathies. This study evaluated the neuroprotective effect of a HECT domain-E3 ubiquitin ligase inhibitor, M01, on retinal ganglion cells after ischemic injury. Experimental anterior ischemic optic neuropathy (AION) was induced by photothrombotic occlusion of microvessels supplying optic nerve in rats. M01 was administered (100 mg/Kg and 200 mg/Kg) subcutaneously for three consecutive days after AION induction. Administration of M01 (100 mg/Kg) significantly increased RGC survival and preserved visual function after AION induction. The number of TUNEL-positive cells and ED1-positive cells was significantly decreased, and optic disc edema was reduced considerably after ischemic infarction with M01 treatment. Moreover, M01 effectively ameliorated optic nerve demyelination and enhanced M2 microglial polarization after AION induction. M01 enhanced the expression of nuclear factor erythroid 2-related factor (Nrf2); subsequently, downregulated Thioredoxin interacting protein (TXNIP) expression, inhibited NLR family pyrin domain containing 3 (NLRP3) activation, and further decreased inflammatory factors, interleukin (IL)-1β and IL-6 in the retina after ischemic injury. These findings suggested that M01 has therapeutic potential by modulating Nrf2 and TXNIP/NLRP3 inflammasome pathways in the retina and optic nerve ischemic damage-related diseases.

Is the clinical course of non-arteritic ischemic optic neuropathy associated with oxidative damage and the dynamics of the antioxidant response?

PURPOSE

Oxidative stress is known to be a decisive factor in the wide etiopathogenesis of optic neuropathy. This study aimed to comprehensively evaluate the interaction of optic neuropathy's clinical course with systemic oxidative damage and antioxidant response dynamics in a large series.

METHODS

This case-controlled clinical study included 33 non-arteritic anterior ischemic optic neuropathy (NAION) patients and 32 healthy individuals. Extensive systemic oxidation profiles were statistically compared between the two groups, and correlations between the clinical and biochemical data in the study group were analyzed.

RESULTS

Vitamin E and malondialdehyde (MDA) levels were significantly higher in the study group. Significant correlations were observed in the analyses between clinical findings and oxidative stress parameters. Correlations between vitamin E and intraocular pressure (IOP), between B12 and cup-to-disk ratio (c/d), between antioxidant glutathione and superoxide dismutase (SOD) enzyme systems, and between uric acid (UA) and age were found to be very significant. As significant correlations were found in either clinical and biochemical data or in oxidative stress parameters, correlations between vitamin E and cholesterol, MDA were found to be very significant.

CONCLUSIONS

This study not only supplies significant information regarding oxidative damage and antioxidant response in NAION, but also points out the specific interactions of neuromodulators, like vitamin E, in intracellular signaling pathways and regulation mechanisms. A better reading of these connections may help improve diagnosis, follow-ups and treatment criteria and strategies.

EYE-503: A Novel Retinoic Acid Drug for Treating Retinal Neurodegeneration

Retinal neurodegeneration is a major cause of vision loss. Retinoic acid signaling is critical for the maintenance of retinal function, and its dysfunction can cause retinal neurodegeneration. However, the therapeutic effects of retinoic acid drugs on retinal neurodegeneration remain unclear. In this study, we designed a novel retinoic acid drug called EYE-503 and investigated its therapeutic effects of EYE-503 on retinal neurodegeneration. The optic nerve crush (ONC) model was selected for the retinal neurodegeneration study. H&E staining, TUNEL staining, immunofluorescence staining, and visual electrophysiology assays were performed to determine the role of EYE-503 in retinal neurodegeneration in vivo. The CCK-8 assay, EdU incorporation assay, PI staining, and flow cytometry assays were performed to investigate the effects of EYE-503 administration on retinal neurodegeneration in vitro. The potential mechanism of EYE-503 in retinal neurodegeneration was investigated by network pharmacology and Western blots. The results showed that EYE-503 administration had no detectable cytotoxicity and tissue toxicity. EYE-503 administration alleviated ONC-induced retinal injury and optic nerve injury in vivo. EYE-503 administration attenuated retinal ganglion cell apoptosis, inhibited reactive gliosis, and retarded the progression of retinal neurodegeneration. Mechanistically, EYE-503 regulated retinal neurodegeneration by targeting the JNK/p38 signaling pathway. This study suggests that EYE-503 is a promising therapeutic agent for retinal neurodegenerative diseases.

Natural products: protective effects against ischemia-induced retinal injury

Ischemic retinal damage, a common condition associated with retinal vascular occlusion, glaucoma, diabetic retinopathy, and other eye diseases, threatens the vision of millions of people worldwide. It triggers excessive inflammation, oxidative stress, apoptosis, and vascular dysfunction, leading to the loss and death of retinal ganglion cells. Unfortunately, minority drugs are available for treating retinal ischemic injury diseases, and their safety are limited. Therefore, there is an urgent need to develop more effective treatments for ischemic retinal damage. Natural compounds have been reported to have antioxidant, anti-inflammatory, and antiapoptotic properties that can be used to treat ischemic retinal damage. In addition, many natural compounds have been shown to exhibit biological functions and pharmacological properties relevant to the treatment of cellular and tissue damage. This article reviews the neuroprotective mechanisms of natural compounds involve treating ischemic retinal injury. These natural compounds may serve as treatments for ischemia-induced retinal diseases.

Rhus Coriaria L. Extract: Antioxidant Effect and Modulation of Bioenergetic Capacity in Fibroblasts from Parkinson’s Disease Patients and THP-1 Macrophages

Sumac, Rhus coriaria L., is a Mediterranean plant showing several useful properties, such as antioxidant and neuroprotective effects. Currently, there is no evidence about its possible neuroprotective action in Parkinson’s disease (PD). We hypothesized that sumac could modulate mitochondrial functionality in fibroblasts of familial early-onset PD patients showing PARK2 mutations. Sumac extract volatile profile, polyphenolic content and antioxidant activity have been previously characterized. We evaluated ROS and ATP levels on sumac-treated patients’ and healthy control fibroblasts. In PD fibroblasts, all treatments were effective in reducing H₂O₂ levels, while patients’ ATP content was modulated differently, probably due to the varying mutations in the PARK2 gene found in individual patients which are also involved in different mitochondrial phenotypes. We also investigated the effect of sumac extract on THP-1-differentiated macrophages, which show different embryogenic origin with respect to fibroblasts. In THP-1 macrophages, sumac treatment determined a reduction in H₂O₂ levels and an increase in the mitochondrial ATP content in M1, assuming that sumac could polarize the M1 to M2 phenotype, as demonstrated with other food-derived compounds rich in polyphenols. In conclusion, Rhus coriaria L. extracts could represent a potential nutraceutical approach to PD.

Optic Neuritis in Multiple Sclerosis—A Review of Molecular Mechanisms Involved in the Degenerative Process

Multiple sclerosis is a central nervous system inflammatory demyelinating disease with a wide range of clinical symptoms, ocular involvement being frequently marked by the presence of optic neuritis (ON). The emergence and progression of ON in multiple sclerosis is based on various pathophysiological mechanisms, disease progression being secondary to inflammation, demyelination, or axonal degeneration. Early identification of changes associated with axonal degeneration or further investigation of the molecular processes underlying remyelination are current concerns of researchers in the field in view of the associated therapeutic potential. This article aims to review and summarize the scientific literature related to the main molecular mechanisms involved in defining ON as well as to analyze existing data in the literature on remyelination strategies in ON and their impact on long-term prognosis.

An automated method for precise axon reconstruction from recordings of high-density micro-electrode arrays

Objective:Neurons communicate with each other by sending action potentials (APs) through their axons. The velocity of axonal signal propagation describes how fast electrical APs can travel. This velocity can be affected in a human brain by several pathologies, including multiple sclerosis, traumatic brain injury and channelopathies. High-density microelectrode arrays (HD-MEAs) provide unprecedented spatio-temporal resolution to extracellularly record neural electrical activity. The high density of the recording electrodes enables to image the activity of individual neurons down to subcellular resolution, which includes the propagation of axonal signals. However, axon reconstruction, to date, mainly relies on manual approaches to select the electrodes and channels that seemingly record the signals along a specific axon, while an automated approach to track multiple axonal branches in extracellular action-potential recordings is still missing.Approach:In this article, we propose a fully automated approach to reconstruct axons from extracellular electrical-potential landscapes, so-called 'electrical footprints' of neurons. After an initial electrode and channel selection, the proposed method first constructs a graph based on the voltage signal amplitudes and latencies. Then, the graph is interrogated to extract possible axonal branches. Finally, the axonal branches are pruned, and axonal action-potential propagation velocities are computed.Main results:We first validate our method using simulated data from detailed reconstructions of neurons, showing that our approach is capable of accurately reconstructing axonal branches. We then apply the reconstruction algorithm to experimental recordings of HD-MEAs and show that it can be used to determine axonal morphologies and signal-propagation velocities at high throughput.Significance:We introduce a fully automated method to reconstruct axonal branches and estimate axonal action-potential propagation velocities using HD-MEA recordings. Our method yields highly reliable and reproducible velocity estimations, which constitute an important electrophysiological feature of neuronal preparations.

Genetic polymorphisms of apolipoprotein E in nonarteritic anterior ischemic optic neuropathy

PURPOSE

To elucidate the potential role of genetic polymorphisms of apolipoprotein E (APOE) in nonarteritic anterior ischemic optic neuropathy (NAION) and the association between APOE and NAION-induced ocular impairments.

METHODS

A total of 73 NAION patients and 73 sex- and age-matched healthy controls were recruited for the study. Genomic DNA was isolated from peripheral blood samples. The alleles and genotypes of APOE were explored. The interaction between APOE and medical comorbidities was assessed by the multifactor dimensionality reduction (MDR) method. Among 81 affected eyes of NAION patients, an additional association study of APOE isoforms with visual impairments was carried out.

RESULTS

The allele and genotype frequencies for APOE showed significant differences when comparing NAION cases and controls. Multivariate analysis adjusted for age, sex, hypertension, dyslipidemia, diabetes mellitus, cardiovascular disease, and cerebrovascular disease revealed that the ε3/ε4 genotype (OR = 3.86, 95% CI = 1.13-13.25, p = 0.032) and ε4 allele (OR = 3.55, 95% CI = 1.05-11.99, p = 0.041) were strong independent risk factors for NAION. Compared to eyes with the ε3/ε3 + ε2/ε4 genotype, individuals with the ε4/ε4 + ε3/ε4 genotype had worse visual field defects (VFDs) and thinner macular ganglion cell complex (mGCC) thicknesses with larger focal loss of volume (FLV) and general loss of volume (GLV). Compared to ε4 noncarriers, ε4 carriers also tended to have more serious VFD and mGCC loss.

CONCLUSIONS

APOE polymorphisms conferred a significant risk of NAION and were significantly related to ocular impairments caused by NAION.

Combination Therapy with Intravitreal Triamcinolone Acetonide and Oral Levodopa for the Treatment of Nonarteritic Anterior Ischemic Optic Neuropathy: A Pilot Study

Purpose: To determine the clinical effectiveness of combination therapy with intravitreal injection of triamcinolone acetonide (IVITA) and oral levodopa in eyes affected by nonarteritic anterior ischemic optic neuropathy (NAION). Methods: Longitudinal study involving 45 eyes of 45 patients with NAION who were evaluated within 14 days of NAION onset. The treatment group received an IVITA 4 mg/0.1 mL followed by 25 mg carbidopa/100 mg levodopa (Sinemet 25-100) 3 times daily for 12 weeks and the control group was untreated. Best-corrected visual acuity (BCVA) converted to logarithmic minimum angle of resolution (logMAR), visual field (VF) grades based on automated or Goldman perimetry, and mean retinal nerve fiber layer (RNFL) thickness measured on optical coherence tomography were assessed at the initial visit, 1, 3, and 6 months after NAION attack. Results: At the first visit and 6 months after NAION onset, the mean logMAR BCVA in the treatment group was significantly better than the control group (P < 0.05). BCVA was not significantly different between onset and the 6-month visit for both the control and the treatment group; however, the change in BCVA after 6 months was significantly greater in the treatment group compared with the control group (P = 0.007). Concomitant systemic disease, the changes in VF grades, and RNFL thickness from initial to 6 months after NAION onset were not significantly different between 2 groups. Conclusions: Combination therapy with IVITA and oral levodopa/carbidopa appears to be effective in the treatment of recent-onset NAION.

Differential Retinal Protein Expression in Primary and Secondary Retinal Ganglion Cell Degeneration Identified by Integrated SWATH and Target-Based Proteomics

To investigate the retinal proteins associated with primary and secondary retinal ganglion cell (RGC) degeneration and explore their molecular pathways, SWATH label-free and target-based mass spectrometry was employed to identify the proteomes in various retinal locations in response to localized optic nerve injury. Unilateral partial optic nerve transection (pONT) was performed on adult Wistar rats and their retinas were harvested 2 weeks later. To confirm the separation of primary and secondary RGC degeneration, immunohistochemistry of RNA binding protein with multiple splicing (RBPMS) and glial fibrillary acidic protein (GFAP) was performed on retinal whole-mounts. Retinal proteomes in the temporal and nasal quadrants were evaluated with high resolution hybrid quadrupole time-of-flight mass spectrometry (QTOF-MS), and SWATH-based acquisition, and their expression was compared to the corresponding retinal quadrant in contralateral control eyes and further validated by multiple reaction monitoring mass spectrometry (MRM-MS). A total of 3641 proteins (FDR < 1%) were identified using QTOF-MS. The raw data are available via ProteomeXchange with the identifier PXD026783. Bioinformatics data analysis showed that there were 37 upregulated and 25 downregulated proteins in the temporal quadrant, whereas 20 and five proteins were upregulated and downregulated, respectively, in the nasal quadrant, respectively (n = 4, p < 0.05; fold change ≥ 1.4-fold or ≤0.7). Six proteins were regulated in both the temporal and the nasal quadrants, including CLU, GFAP, GNG5, IRF2BPL, L1CAM, and CPLX1. Linear regression analysis indicated a strong association between the data obtained by means of SWATH-MS and MRM-MS (temporal, R² = 0.97; nasal, R² = 0.96). Gene ontology analysis revealed statistically significant changes in the biological processes and cellular components of primary RGC degeneration. The majority of the significant changes in structural, signaling, and cell death proteins were associated with the loss of RGCs in the area of primary RGC degeneration. The combined use of SWATH-MS and MRM-MS methods detects and quantifies regional changes of retinal protein expressions after localized injury. Future investigation with this integrated approach will significantly increase the understanding of diverse processes of progressive RGC degeneration from a proteomic prospective.

Immuno-histological detection of resistant columnar units and vulnerable networks in the rat retina after asphyxia-induced transient cardiac arrest

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.

Protection against experimental cisplatin-induced optic nerve toxicity using resveratrol: A rat model study

AIM

To investigate the effects of resveratrol on oxidative stress and inflammation parameters and histological alterations in cisplatin-induced optic nerve damage in a mouse model.

MATERIAL AND METHOD

Thirty-six albino Wistar male rats were divided into three groups as control, 5 mg/kg cisplatin-administered (Cis) and 5 mg/kg cisplatin + 25 mg/kg resveratrol-administered (Cis + Res) animals. At the end of the experimental period, the rats were sacrificed with high-dose (50 mg/kg) thiopental sodium, and their optic nerves were dissected. Malondialdehyde (MDA), total glutathione (tGSH), total oxidant status (TOS), total antioxidant status (TAS), tumour necrosis factor alpha (TNF-α), nuclear factor kappa B (NF-KB) levels, and histopathological findings were assessed using the optic nerve tissues.

RESULTS

In the Cis + Res group, the MDA, TOS, OSI, TNF-a and NFK-B levels were significantly lower and the tGSH and TAS levels were significantly higher compared with the Cis group (P = 0.001). In histological evaluations, there were dilated and congested blood vessels, destruction, oedema, degeneration, haemorrhage, and proliferating capillaries indicating the presence of inflammation and damage only in the Cis-administered group. However, in the Cis + Res group, the histological findings were very similar to the healthy controls.

CONCLUSION

Resveratrol is a promising neuroprotective agent for cisplatin-induced optic nerve toxicity with its anti-oxidant and anti-inflammatory effects. Further investigations are needed to evaluate the possible therapeutic effects on other optic nerve toxicities.

Protective Effects of Oroxylin A on Retinal Ganglion Cells in Experimental Model of Anterior Ischemic Optic Neuropathy

Nonarteritic anterior ischemic optic neuropathy (NAION) is the most common cause of acute vision loss in older people, and there is no effective therapy. The effect of the systemic or local application of steroids for NAION patients remains controversial. Oroxylin A (OA) (5,7-dihydroxy-6-methoxyflavone) is a bioactive flavonoid extracted from Scutellariae baicalensis Georgi. with various beneficial effects, including anti-inflammatory and neuroprotective effects. A previous study showed that OA promotes retinal ganglion cell (RGC) survival after optic nerve (ON) crush injury. The purpose of this research was to further explore the potential actions of OA in ischemic injury in an experimental anterior ischemic optic neuropathy (rAION) rat model induced by photothrombosis. Our results show that OA efficiently attenuated ischemic injury in rats by reducing optic disc edema, the apoptotic death of retinal ganglion cells, and the infiltration of inflammatory cells. Moreover, OA significantly ameliorated the pathologic changes of demyelination, modulated microglial polarization, and preserved visual function after rAION induction. OA activated nuclear factor E2 related factor (Nrf2) signaling and its downstream antioxidant enzymes NAD(P)H:quinone oxidoreductase (NQO-1) and heme oxygenase 1 (HO-1) in the retina. We demonstrated that OA activates Nrf2 signaling, protecting retinal ganglion cells from ischemic injury, in the rAION model and could potentially be used as a therapeutic approach in ischemic optic neuropathy.

Increased Retinal Ganglion Cell Survival by Exogenous IL-2 Depends on IL-10, Dopamine D1 Receptors, and Classical IL-2/IL-2R Signaling Pathways

Interleukin-2 (IL-2) is a classical pro-inflammatory cytokine known to display neuroprotective roles in the central nervous system including the retina. In the present study, we investigate the molecular targets involved in the neurotrophic effect of IL-2 on retinal ganglion cells (RGC) after optic nerve axotomy. Analysis of retrograde labeling of RGC showed that common cell survival mediators, as Trk receptors, Src, PI3K, PKC, and intracellular calcium do not mediate the neurotrophic effect of IL-2 on RGC. No involvement of MAPK p38 was also observed. However, other MAPKs as MEK and JNK appear to be mediating this IL-2 effect. Our data also indicate that JAK2/3 are important intracellular proteins for the IL-2 effect. Interestingly, we demonstrate that the IL-2 effect depends on dopamine D1 receptors (D1R), the cAMP/PKA pathway, interleukin-10 (IL-10), and NF-κB, suggesting that RGC survival induced by IL-2 encompasses a molecular network of major complexity. In addition, treatment of retinal cells with recombinant IL-10 or 6-Cl-pb (D1R full agonist) was able to increase RGC survival similar to IL-2. Taken together, our results suggest that after optic nerve axotomy, the increase in RGC survival triggered by IL-2 is mediated by IL-10 and D1R along with the intracellular pathways of MAPKs, JAK/STAT, and cAMP/PKA.

Citicoline in Ophthalmological Neurodegenerative Disease: A Comprehensive Review

Cytidine 5'-diphosphocholine has been widely studied in systemic neurodegenerative diseases, like Alzheimer's disease, Parkinson's disease, and brain ischemia. The rationale for the use of citicoline in ophthalmological neurodegenerative diseases, including glaucoma, anterior ischemic optic neuropathy, and diabetic retinopathy, is founded on its multifactorial mechanism of action and the involvement in several metabolic pathways, including phospholipid homeostasis, mitochondrial dynamics, as well as cholinergic and dopaminergic transmission, all being involved in the complexity of the visual transmission. This narrative review is aimed at reporting both pre-clinical data regarding the involvement of citicoline in such metabolic pathways (including new insights about its role in the intracellular proteostasis through an interaction with the proteasome) and its effects on clinical psychophysical, electrophysiological, and morphological outcomes following its use in ophthalmological neurodegenerative diseases (including the results of the most recent prospective randomized clinical trials).

Pharmacological and Antioxidant Activities of Rhus coriaria L. (Sumac)

Rhus coriaria L. (Anacardiaceae), commonly known as sumac, is a commonly used spice, condiment, and flavoring agent, especially in the Mediterranean region. Owing to its bountiful beneficial values, sumac has been used in traditional medicine for the management and treatment of many ailments including hemorrhoids, wound healing, diarrhea, ulcer, and eye inflammation. This plant is rich in various classes of phytochemicals including flavonoids, tannins, polyphenolic compounds, organic acids, and many others. By virtue of its bioactive, Rhus coriaria possesses powerful antioxidant capacities that have ameliorative and therapeutic benefits for many common diseases including cardiovascular disease, diabetes, and cancer. This review describes the phytochemical properties of R. coriaria and then focuses on the potent antioxidant capacities of sumac. We then dissect the cellular and molecular mechanisms of sumac’s action in modulating many pathophysiological instigators. We show how accumulating evidence supports the antibacterial, antinociceptive, antidiabetic, cardioprotective, neuroprotective, and anticancer effects of this plant, especially that toxicity studies show that sumac is very safe to consume by humans and has little toxicity. Taken together, the findings we summarize here support the utilization of this plant as an attractive target for drug discovery.

Analysis of Macular Microperimetry Characteristics in Non-Arteritic Anterior Ischemic Optic Neuropathy

Background

The aim of this study was to analyze the correlation of macular micro-field characteristics with vision and visual field in patients with non-arteritic anterior ischemic optic neuropathy.

Material/Methods

Retrospective case analysis was performed. Fifty-eight NAION patients with 62 affected eyes were included in the study. In addition, 54 eyes not affected by NAION from 54 patients among the 58 patients were included as controls. All eyes underwent best corrected visual acuity (BCVA) test, slit lamp biomicroscopy, indirect ophthalmoscopy, visual field examination, and microperimetry. BCVA was converted into logarithm of minimum angle of resolution (LogMAR) for statistical analysis. There was no significant difference in age, sex, eye type, or intraocular pressure between the 2 groups. The macular integrity assessment (MAIA) instrument was used for microperimetry. Mean light sensitivity (microMS) in the 10° macular region and the fixation rates for macular fovea 2° and 4° were recorded. Spearman correlation analysis was performed.

Results

The microMS values were significantly different between the control group and the affected eye group (t=−2.427, P=0.036). MicroMS was significantly correlated with logMAR BCVA (r=−0.802, P=−0.005) and with mean sensitivity (MS) and mean deviation (MD) (r=0.912, P=0.002; r=−0.905, P=0.002; P<0.05). MS and MD were not correlated with logMAR BCVA (r=−0.465, P=0.245; r=0.437, P=0.278).

Conclusions

The present study demonstrates that microMS of macular micro-visual field in NAION patients was significantly decreased at early stage, and was significantly correlated with and consistent with visual acuity and visual field.

Diagnosis of ischemic optic neuropathy caused by dissection of the internal carotid artery: A case report

RATIONALE

Ischemic optic neuropathy (ION), due to diseases of the arteries supplying the optic nerve, is an ischemic damage of the optic nerve. This report highlights a case with monocular decreasing visual acuity caused by dissection of the internal carotid artery (ICA), which is a relatively rare cause for ION.

PATIENT CONCERNS

A 44-year-old woman presented with a decreasing visual acuity and defected visual field in the right eye for 1 week. The best corrected visual acuity (BCVA) was 20/400 in the right eye, and 20/20 in the left eye. In the right eye, the pupil showed little reaction to light with a relative afferent pupillary defect. The visual field test disclosed a defect in the inferior field connecting to the blind spot. Electroretinogram recording showed no obviously declined retinal function. No recognizable waveforms were presented in pattern visual-evoked potential (PVEP) examination, whereas the flash visual-evoked potential result revealed a delayed peak time and a reduced amplitude of P2-wave.

DIAGNOSIS

The patient was diagnosed as ION with the aid of computed tomographic angiography of the brain and neck, which revealed a stenosis in the right ICA and an occlusion in the right cerebral middle artery. The stenosis was verified as dissection of the ICA by digital subtraction angiography.

INTERVENTIONS

Based on the clinical findings, stent implantation inside the right ICA was performed.

OUTCOMES

The ICA was recanalized soon and the BCVA of the right eye was improved to be 20/25 five months later. A second PVEP examination revealed a recognizable waveform in the right eye, although the peak time and amplitude of the P100-wave was a bit abnormal compared to that of the left eye.

LESSONS

ION with the sign of decreasing monocular visual acuity could occur due to dissection of the ICA, with no obvious neurologic symptom at the beginning. The present case emphasizes the importance of suspicion of ICA problems as the underlying cause for ION, which could help to take in-time measure to save the vision and avoid further complications.

Rhus coriaria L. Fruit Extract Prevents UV-A-Induced Genotoxicity and Oxidative Injury in Human Microvascular Endothelial Cells

Rhus coriaria L. (sumac) is a small plant widely diffused in the Mediterranean region. Its fruit are often consumed as a spice but are also present in traditional medicine of several countries. Recently, interest in this plant has increased and many scientific works reported its beneficial effects including antioxidant and anti-inflammatory properties. Plant extracts can be successfully used against ultraviolet rays, which are able to reach and damage the human skin; however, sumac extracts were never applied to this usage. Thus, in this study, we used a macerated ethanol extract of Rhus coriaria L. dried fruit (mERC) to demonstrate its preventive role against the damage induced by ultraviolet-A rays (UV-A) on microvascular endothelial cells (HMEC-1). In vitro effects of the extract pre-treatment and UV-A exposure were evaluated in detail. The antioxidant capacity was assessed by reactive oxygen species (ROS) formation and cellular antioxidant activity measurement. Genoprotective effects of mERC were investigated as well. Our findings indicate that the extract acts as a cell cycle inhibitor or apoptosis inducer, according to the level of damage. The present work provides new insights into the usage of Rhus coriaria extracts against skin injuries.

Neuroenhancement and neuroprotection by oral solution citicoline in non-arteritic ischemic optic neuropathy as a model of neurodegeneration: A randomized pilot study

PURPOSE

To evaluate whether treatment with Citicoline in oral solution (OS-Citicoline) would increase visual function, retinal ganglion cells (RGCs) function, and neural conduction along visual pathways (neuroenhancement), and/or induce preservation of RGCs fibers' loss (neuroprotection) in non-arteritic ischemic optic neuropathy (NAION), a human model of neurodegeneration.

METHODS

Thirty-six patients with NAION and 20 age-matched controls were enrolled. Nineteen NAION patients received 500 mg/day of OS-Citicoline for a 6-month period followed by 3-month of wash-out (NC Group); 17 NAION patients were not treated (NN Group) from baseline to 9 months. In all subjects at baseline, and in NC and NN eyes at 6 and 9 months of follow-up, we assessed Visual Acuity (VA), Pattern Electroretinogram (PERG), Visual Evoked Potentials (VEP), retinal nerve fiber layer thickness (RNFL-T), and Humphrey 24-2 visual field mean deviation (HFA MD). Mean differences were statistically evaluated with ANOVA between Groups, and linear correlations were analysed with Pearson's test.

RESULTS

At 6 months, significant differences between groups for all parameters were observed (ANOVA, p<0.01). In NC eyes, VA increased, PERG responses increased, VEP recordings improved and were significantly correlated with increases in HFA MD (p<0.01), and RNFL-T was unmodified or improved. In contrast, in NN eyes, VA, PERG, VEP responses, RNFL-T, and HFA MD were further worsened. Significant differences were still present at 9-month follow-up in the NN Group and after 3 months of OS-Citicoline wash-out in NC eyes.

CONCLUSIONS

OS-Citicoline treatment induced neuroenhancement (improvement in RGCs function and neural conduction along visual pathways related to improvement of visual field defects) and neuroprotection (unmodified or improved RNFL morphological condition) in a human model of NAION involving fast RGCs degeneration.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03758118.

Technologies to Study Action Potential Propagation With a Focus on HD-MEAs

Axons convey information in neuronal circuits via reliable conduction of action potentials (APs) from the axon initial segment (AIS) to the presynaptic terminals. Recent experimental findings increasingly evidence that the axonal function is not limited to the simple transmission of APs. Advances in subcellular-resolution recording techniques have shown that axons display activity-dependent modulation in spike shape and conduction velocity, which influence synaptic strength and latency. We briefly review here, how recent methodological developments facilitate the understanding of the axon physiology. We included the three most common methods, i.e., genetically encoded voltage imaging (GEVI), subcellular patch-clamp and high-density microelectrode arrays (HD-MEAs). We then describe the potential of using HD-MEAs in studying axonal physiology in more detail. Due to their robustness, amenability to high-throughput and high spatiotemporal resolution, HD-MEAs can provide a direct functional electrical readout of single cells and cellular ensembles at subcellular resolution. HD-MEAs can, therefore, be employed in investigating axonal pathologies, the effects of large-scale genomic interventions (e.g., with RNAi or CRISPR) or in compound screenings. A combination of extracellular microelectrode arrays (MEAs), intracellular microelectrodes and optical imaging may potentially reveal yet unexplored repertoires of axonal functions.

Neuroprotective and Anti-Inflammatory Effects of Rhus coriaria Extract in a Mouse Model of Ischemic Optic Neuropathy

Modulating oxidative stresses and inflammation can potentially prevent or alleviate the pathological conditions of diseases associated with the nervous system, including ischemic optic neuropathy. In this study we evaluated the anti-neuroinflammatory and neuroprotective activities of Rhus coriaria (R. coriaria) extract in vivo. The half maximal inhibitory concentration (IC₅₀) for DPPH, ABTS and &beta;⁻carotene were 6.79 &plusmn; 0.009 &micro;g/mL, 10.94 &plusmn; 0.09 &micro;g/mL, and 6.25 &plusmn; 0.06 &micro;g/mL, respectively. Retinal ischemia was induced by optic nerve crush injury in albino Balb/c mice. The anti-inflammatory activity of ethanolic extract of R. coriaria (ERC) and linoleic acid (LA) on ocular ischemia was monitored using Fluorescence Molecular Tomography (FMT). Following optic nerve crush injury, the mice treated with 400 mg/kg of ERC and LA exhibited an 84.87% and 86.71% reduction of fluorescent signal (cathepsin activity) respectively. The results of this study provide strong scientific evidence for the neuroprotective activity of the ERC, identifying LA as one of the main components responsible for the effect. ERC may be useful and worthy of further development for its adjunctive utilization in the treatment of optic neuropathy.