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Scientific Reports Jun 2024To evaluate the protective effect of gallic acid on the optic nerve by studying the inhibitory effect of gallic acid on oxidative stress in retinal ganglion cells. 100...
To evaluate the protective effect of gallic acid on the optic nerve by studying the inhibitory effect of gallic acid on oxidative stress in retinal ganglion cells. 100 male SD rats were randomly divided into four groups: normal control group, simple high IOP group, 0.5% gallic acid experimental group, and 1% gallic acid experimental group. HE staining, immunofluorescence, DHE staining, Western blot, and q-PCR were used to observe the antioxidant effect of gallic acid on the retina of acute ocular hypertension rats. HE staining of the retina of SD rats confirmed that the nucleus of RGCs was clear, the thickness of the RNFL was regular in the normal control group, and the nucleus of RGCs was ruptured and lysed in the simple high intraocular pressure (IOP) group and the gallic acid group, and the thickness of the RNFL was significantly thickened, but the thickness of the RNFL in the gallic acid group was significantly reduced compared with that in the simple high IOP group (p < 0.05). DHE staining showed that ROS content in the simple high IOP group was significantly increased compared with the normal control group, and ROS content was significantly decreased after the application of gallic acid (p < 0.05). Immunofluorescence staining with Brn-3a antibody confirmed that the number of RGCs was significantly reduced in the simple high IOP group compared with the normal control group, whereas after application of gallic acid, the number of RGCs was significantly more in the gallic acid group than in the simple high IOP group (p < 0.05). Western Blot and q-PCR confirmed that hypoxia-inducing factor 1α (HIF-1α) protein content and transcription level were significantly increased in the retinal tissue of the simple high IOP group, and gallic acid could inhibit HIF-1α protein content (p < 0.05) and reduce transcription factor level (p < 0.05). Gallic acid exerts a protective effect on RGC by inhibiting oxidative stress in rats with acute IOP elevation.
Topics: Gallic Acid; Animals; Retinal Ganglion Cells; Antioxidants; Male; Rats; Rats, Sprague-Dawley; Disease Models, Animal; Glaucoma; Oxidative Stress; Reactive Oxygen Species; Hypoxia-Inducible Factor 1, alpha Subunit; Intraocular Pressure; Ocular Hypertension
PubMed: 38942959
DOI: 10.1038/s41598-024-65965-7 -
Cell Death Discovery Jun 2024This study assesses the neuroprotective potential of CPP-P1, a conjugate of an anti-apoptotic peptain-1 (P1) and a cell-penetrating peptide (CPP) in in vitro, in vivo,...
This study assesses the neuroprotective potential of CPP-P1, a conjugate of an anti-apoptotic peptain-1 (P1) and a cell-penetrating peptide (CPP) in in vitro, in vivo, and ex vivo glaucoma models. Primary retinal ganglion cells (RGCs) were subjected to either neurotrophic factor (NF) deprivation for 48 h or endothelin-3 (ET-3) treatment for 24 h and received either CPP-P1 or vehicle. RGC survival was analyzed using a Live/Dead assay. Axotomized human retinal explants were treated with CPP-P1 or vehicle for seven days, stained with RGC marker RBPMS, and RGC survival was analyzed. Brown Norway (BN) rats with elevated intraocular pressure (IOP) received weekly intravitreal injections of CPP-P1 or vehicle for six weeks. RGC function was evaluated using a pattern electroretinogram (PERG). RGC and axonal damage were also assessed. RGCs from ocular hypertensive rats treated with CPP-P1 or vehicle for seven days were isolated for transcriptomic analysis. RGCs subjected to 48 h of NF deprivation were used for qPCR target confirmation. NF deprivation led to a significant loss of RGCs, which was markedly reduced by CPP-P1 treatment. CPP-P1 also decreased ET-3-mediated RGC death. In ex vivo human retinal explants, CPP-P1 decreased RGC loss. IOP elevation resulted in significant RGC loss in mid-peripheral and peripheral retinas compared to that in naive rats, which was significantly reduced by CPP-P1 treatment. PERG amplitude decline in IOP-elevated rats was mitigated by CPP-P1 treatment. Following IOP elevation in BN rats, the transcriptomic analysis showed over 6,000 differentially expressed genes in the CPP-P1 group compared to the vehicle-treated group. Upregulated pathways included CREB signaling and synaptogenesis. A significant increase in Creb1 mRNA and elevated phosphorylated Creb were observed in CPP-P1-treated RGCs. Our study showed that CPP-P1 is neuroprotective through CREB signaling enhancement in several settings that mimic glaucomatous conditions. The findings from this study are significant as they address the pressing need for the development of efficacious therapeutic strategies to maintain RGC viability and functionality associated with glaucoma.
PubMed: 38942762
DOI: 10.1038/s41420-024-02070-8 -
Neurology(R) Neuroimmunology &... Sep 2024To systematically describe the clinical picture of double-antibody seronegative neuromyelitis optica spectrum disorders (DN-NMOSD) with specific emphasis on retinal...
BACKGROUND AND OBJECTIVES
To systematically describe the clinical picture of double-antibody seronegative neuromyelitis optica spectrum disorders (DN-NMOSD) with specific emphasis on retinal involvement.
METHODS
Cross-sectional data of 25 people with DN-NMOSD (48 eyes) with and without a history of optic neuritis (ON) were included in this study along with data from 25 people with aquaporin-4 antibody seropositive neuromyelitis optica spectrum disorder (AQP4-NMOSD, 46 eyes) and from 25 healthy controls (HCs, 49 eyes) for comparison. All groups were matched for age and sex and included from the collaborative retrospective study of retinal optical coherence tomography (OCT) in neuromyelitis optica (CROCTINO). Participants underwent OCT with central postprocessing and local neurologic examination and antibody testing. Retinal neurodegeneration was quantified as peripapillary retinal nerve fiber layer thickness (pRNFL) and combined ganglion cell and inner plexiform layer thickness (GCIPL).
RESULTS
This DN-NMOSD cohort had a history of [median (inter-quartile range)] 6 (5; 9) attacks within their 5 ± 4 years since onset. Myelitis and ON were the most common attack types. In DN-NMOSD eyes after ON, pRNFL ( < 0.001) and GCIPL ( = 0.023) were thinner compared with eyes of HCs. Even after only one ON episode, DN-NMOSD eyes already had considerable neuroaxonal loss compared with HCs. In DN-NMOSD eyes without a history of ON, pRNFL ( = 0.027) and GCIPL ( = 0.022) were also reduced compared with eyes of HCs. However, there was no difference in pRNFL and GCIPL between DN-NMOSD and AQP4-NMOSD for the whole group and for subsets with a history of ON and without a history of ON-as well as between variances of retinal layer thicknesses.
DISCUSSION
DN-NMOSD is characterized by severe retinal damage after ON and attack-independent retinal neurodegeneration. Most of the damage occurs during the first ON episode, which highlights the need for better diagnostic markers in DN-NMOSD to facilitate an earlier diagnosis as well as for effective and early treatments. In this study, people with DN-NMOSD presented with homogeneous clinical and imaging findings potentially suggesting a common retinal pathology in these patients.
Topics: Humans; Neuromyelitis Optica; Female; Male; Adult; Cross-Sectional Studies; Middle Aged; Tomography, Optical Coherence; Aquaporin 4; Retrospective Studies; Autoantibodies; Retina
PubMed: 38941573
DOI: 10.1212/NXI.0000000000200273 -
Neurology(R) Neuroimmunology &... Sep 2024Retinal optical coherence tomography (OCT) provides promising prognostic imaging biomarkers for future disease activity in multiple sclerosis (MS). However, raw...
BACKGROUND AND OBJECTIVES
Retinal optical coherence tomography (OCT) provides promising prognostic imaging biomarkers for future disease activity in multiple sclerosis (MS). However, raw OCT-derived measures have multiple dependencies, supporting the need for establishing reference values adjusted for possible confounders. The purpose of this study was to investigate the capacity for age-adjusted scores of OCT-derived measures to prognosticate future disease activity and disability worsening in people with MS (PwMS).
METHODS
We established age-adjusted OCT reference data using generalized additive models for location, scale, and shape for peripapillary retinal nerve fiber layer (pRNFL) and ganglion cell-inner plexiform layer (GCIP) thicknesses, involving 910 and 423 healthy eyes, respectively. Next, we transformed the retinal layer thickness of PwMS from 3 published studies into age-adjusted scores (pRNFL-z and GCIP-z) based on the reference data. Finally, we investigated the association of pRNFL-z or GCIP-z as predictors with future confirmed disability worsening (Expanded Disability Status Scale score increase) or disease activity (failing of the no evidence of disease activity [NEDA-3] criteria) as outcomes. Cox proportional hazards models or logistic regression analyses were applied according to the original studies. Optimal cutoffs were identified using the Akaike information criterion as well as location with the log-rank and likelihood-ratio tests.
RESULTS
In the first cohort (n = 863), 172 PwMS (24%) had disability worsening over a median observational period of 2.0 (interquartile range [IQR]:1.0-3.0) years. Low pRNFL-z (≤-2.04) were associated with an increased risk of disability worsening (adjusted hazard ratio (aHR) [95% CI] = 2.08 [1.47-2.95], 3.82e). In the second cohort (n = 170), logistic regression analyses revealed that lower pRNFL-z showed a higher likelihood for disability accumulation at the two-year follow-up (reciprocal odds ratio [95% CI] = 1.51[1.06-2.15], = 0.03). In the third cohort (n = 78), 46 PwMS (59%) did not maintain the NEDA-3 status over a median follow-up of 2.0 (IQR: 1.9-2.1) years. PwMS with low GCIP-z (≤-1.03) had a higher risk of showing disease activity (aHR [95% CI] = 2.14 [1.03-4.43], = 0.04). Compared with raw values with arbitrary cutoffs, applying the score approach with optimal cutoffs showed better performance in discrimination and calibration (higher Harrell's concordance index and lower integrated Brier score).
DISCUSSION
In conclusion, our work demonstrated reference cohort-based scores that account for age, a major driver for disease progression in MS, to be a promising approach for creating OCT-derived measures useable across devices and toward individualized prognostication.
Topics: Humans; Female; Male; Tomography, Optical Coherence; Adult; Middle Aged; Disease Progression; Prognosis; Multiple Sclerosis; Retina; Severity of Illness Index
PubMed: 38941572
DOI: 10.1212/NXI.0000000000200269 -
Journal of Pediatric Ophthalmology and... Jun 2024To compare children's stereometric optic disc parameters and inner retinal thickness measured by optical coherence tomography (OCT) in two different moments in life in...
PURPOSE
To compare children's stereometric optic disc parameters and inner retinal thickness measured by optical coherence tomography (OCT) in two different moments in life in the same children and to establish a correlation between the optic nerve head (ONH) area and the difference of these parameters in the two observations.
METHODS
In this observational cohort, children were evaluated on two occasions: at 6.7 ± 1.6 and 13.2 ± 0.7 years of age. Cup volume, neuroretinal rim (NRR) area, average cup-to-disc ratio, peripapillary retinal nerve fiber layer (pRNFL), and ganglion cell inner plexiform layer (GCIPL) were measured by the Cirrus HD-OCT (Carl Zeiss Meditec AG).
RESULTS
A total of 175 children were included, 89 boys (50.9%) and 86 girls (49.1%). There was a significant decrease of the NRR area ( < .001) and increase of the cup volume ( < .001) on the second observation. The pRNFL thickness and GCIPL thickness also decreased ( < .001 and = .002, respectively). There was a positive correlation between the ONH area and the difference of the cup volume ( = .047; = 0.102) and a negative correlation with the difference of the NRR area ( < .001; = 0.237).
CONCLUSIONS
During childhood, there is an increase of the cup volume, a decrease of the NRR area, and a decrease of inner retinal layer thickness (more significant in the superior and inferior quadrants) measured by OCT. This study demonstrates that in children with large discs the enlargement of the cup and decrease of the NRR is more evident. Considering these changes, the physiological enlargement of the cup in a child with a large disc can be misinterpreted as the development of a glaucomatous lesion. .
PubMed: 38940309
DOI: 10.3928/01913913-20240521-01 -
Frontiers in Bioscience (Landmark... May 2024Circadian rhythms, the natural cycles of physical, mental, and behavioral changes that follow a roughly 24-hour cycle, are known to have a profound effect on the human... (Review)
Review
Circadian rhythms, the natural cycles of physical, mental, and behavioral changes that follow a roughly 24-hour cycle, are known to have a profound effect on the human body. Light plays an important role in the regulation of circadian rhythm in human body. When light from the outside enters the eyes, cones, rods, and specialized retinal ganglion cells receive the light signal and transmit it to the suprachiasmatic nucleus of the hypothalamus. The central rhythm oscillator of the suprachiasmatic nucleus regulates the rhythm oscillator of tissues all over the body. Circadian rhythms, the natural cycles of physical, mental, and behavioral changes that follow a roughly 24-hour cycle, are known to have a profound effect on the human body. As the largest organ in the human body, skin plays an important role in the peripheral circadian rhythm regulation system. Like photoreceptor cells in the retina, melanocytes express opsins. Studies show that melanocytes in the skin are also sensitive to light, allowing the skin to "see" light even without the eyes. Upon receiving light signals, melanocytes in the skin release hormones that maintain homeostasis. This process is called "photoneuroendocrinology", which supports the health effects of light exposure. However, inappropriate light exposure, such as prolonged work in dark environments or exposure to artificial light at night, can disrupt circadian rhythms. Such disruptions are linked to a variety of health issues, emphasizing the need for proper light management in daily life. Conversely, harnessing light's beneficial effects through phototherapy is gaining attention as an adjunctive treatment modality. Despite these advancements, the field of circadian rhythm research still faces several unresolved issues and emerging challenges. One of the most exciting prospects is the use of the skin's photosensitivity to treat diseases. This approach could revolutionize how we think about and manage various health conditions, leveraging the skin's unique ability to respond to light for therapeutic purposes. As research continues to unravel the complexities of circadian rhythms and their impact on health, the potential for innovative treatments and improved wellbeing is immense.
Topics: Humans; Circadian Rhythm; Animals; Light; Signal Transduction
PubMed: 38940028
DOI: 10.31083/j.fbl2906206 -
Expert Opinion on Biological Therapy Jun 2024Leber hereditary optic neuropathy (LHON) is among the most frequent inherited mitochondrial disease, causing a severe visual impairment, mostly in young-adult males. The... (Review)
Review
INTRODUCTION
Leber hereditary optic neuropathy (LHON) is among the most frequent inherited mitochondrial disease, causing a severe visual impairment, mostly in young-adult males. The causative mtDNA variants (the three common are m.11778 G>A/MT-ND4, m.3460 G>A/MT-ND1, and m.14484T>C/MT-ND6) by affecting complex I impair oxidative phosphorylation in retinal ganglion cells, ultimately leading to irreversible cell death and consequent functional loss. The gene therapy based on allotopic expression of a wild-type transgene carried by adeno-associated viral vectors (AVV-based) appears a promising approach in mitochondrial disease and its efficacy has been explored in several large clinical trials.
AREAS COVERED
The review work employed basic concepts in mitochondrial diseases, LHON, and gene therapy procedures. Reports from completed trials in LHON (i.e. RESCUE) were reviewed and critically compared.
EXPERT OPINION
New challenges, as the improvement of the contralateral untreated eye or the apparently better outcome in patients treated in later stages (6-12 months), were highlighted by the latest gene therapy trials. A better understanding of the pathogenetic mechanisms of the disease together with combined therapy (medical and gene therapy) and optimization in genetic correction approaches could improve the visual outcome of treated eyes.
Topics: Optic Atrophy, Hereditary, Leber; Humans; Genetic Therapy; DNA, Mitochondrial; Animals; Dependovirus; Genetic Vectors
PubMed: 38939999
DOI: 10.1080/14712598.2024.2359015 -
ENeuro Jun 2024Elevated intraocular pressure (IOP) triggers glaucoma by damaging the output neurons of the retina called retinal ganglion cells (RGCs). This leads to the loss of RGC...
Elevated intraocular pressure (IOP) triggers glaucoma by damaging the output neurons of the retina called retinal ganglion cells (RGCs). This leads to the loss of RGC signaling to visual centers of the brain such as the dorsolateral geniculate nucleus (dLGN), which is critical for processing and relaying information to the cortex for conscious vision. In response to altered levels of activity or synaptic input, neurons can homeostatically modulate postsynaptic neurotransmitter receptor numbers, allowing them to scale their synaptic responses to stabilize spike output. While prior work has indicated unaltered glutamate receptor properties in the glaucomatous dLGN, it is unknown whether glaucoma impacts dLGN inhibition. Here, using DBA/2J mice, which develop elevated IOP beginning at 6-7 months of age, we tested whether the strength of inhibitory synapses on dLGN thalamocortical relay neurons is altered in response to the disease state. We found an enhancement of feed-forward disynaptic inhibition arising from local interneurons along with increased amplitude of quantal inhibitory synaptic currents. A combination of immunofluorescence staining for the GABA-α1 receptor subunit, peak-scaled nonstationary fluctuation analysis, and measures of homeostatic synaptic scaling pointed to an approximately 1.4-fold increase in GABA receptors at post-synaptic inhibitory synapses, although several pieces of evidence indicate a non-uniform scaling across inhibitory synapses within individual relay neurons. Together, these results indicate an increase in inhibitory synaptic strength in the glaucomatous dLGN, potentially pointing toward homeostatic compensation for disruptions in network and neuronal function triggered by increased IOP. Elevated eye pressure in glaucoma leads to loss of retinal outputs to the dorsolateral geniculate nucleus (dLGN), which is critical for relaying information to the cortex for conscious vision. Alterations in neuronal activity, as could arise from excitatory synapse loss, can trigger homeostatic adaptations to synaptic function that attempt to maintain activity within a meaningful dynamic range, although whether this occurs uniformly at all synapses within a given neuron or is a non-uniform process is debated. Here, using a mouse model of glaucoma, we show that dLGN inhibitory synapses undergo non-uniform upregulation due to addition of post-synaptic GABA receptors. This is likely to be a neuronal adaptation to glaucomatous pathology in an important sub-cortical visual center.
PubMed: 38937109
DOI: 10.1523/ENEURO.0263-24.2024 -
In Vivo (Athens, Greece) 2024Diabetic retinopathy is a leading cause of blindness worldwide, characterized by neurovascular dysfunction. This study aimed to investigate the impact of brimonidine, a...
BACKGROUND/AIM
Diabetic retinopathy is a leading cause of blindness worldwide, characterized by neurovascular dysfunction. This study aimed to investigate the impact of brimonidine, a selective adrenoceptor agonist, on diabetic retinal neurodegeneration, recognizing the critical role of neurodegeneration in diabetic retinopathy.
MATERIALS AND METHODS
Streptozotocin-induced diabetes was established in adult male Sprague-Dawley rats to mimic diabetic retinopathy. Rats, except non-diabetic control rats, received topical applications of 0.15% brimonidine tartrate (treatment group) or balanced salt solution (diabetic control group) twice daily following diabetes induction. Each group comprised six randomly assigned animals. Retinal samples were analyzed using immunofluorescence staining, apoptosis assay, and western blot.
RESULTS
Topical brimonidine treatment reduced apoptosis of retinal ganglion cells at 8 weeks after induction of diabetes (p<0.05). Glial activation induced by diabetes was reduced by brimonidine treatment. Immunoblot and immunofluorescence assay revealed that the decrease in phospho- protein kinase B (AKT) level resulting from diabetes was also attenuated by brimonidine (p<0.05). Furthermore, brimonidine alleviated the decrease in anti-apoptotic proteins [BCL2 apoptosis regulator (BCL2) and BCL-xl] induced by diabetes (p<0.05). Elevation of phospho-p38 mitogen-activated protein kinase (p38MAPK) and p53 in diabetic rats were reduced by brimonidine (p<0.05). Additionally, brimonidine treatment attenuated the upregulation of the pro-apoptotic molecule BCL-2 associated X in retinas of diabetic rats (p<0.05).
CONCLUSION
These findings suggest that topical brimonidine treatment may protect retinal ganglion cells in experimental diabetes by modulating the AKT pathway and reducing pro-apoptotic p38MAPK levels. This presents a potential neuroprotective approach in diabetes, offering the advantage of localized treatment without the added burden of oral medication.
Topics: Animals; Diabetic Retinopathy; Brimonidine Tartrate; Neuroprotective Agents; Rats; Apoptosis; Diabetes Mellitus, Experimental; Male; Retinal Ganglion Cells; Administration, Topical; Disease Models, Animal; Rats, Sprague-Dawley; Proto-Oncogene Proteins c-akt; Retina
PubMed: 38936912
DOI: 10.21873/invivo.13611 -
Investigative Ophthalmology & Visual... Jun 2024Retinal ganglion cells (RGCs) connect the retina to the brain. Proper development of the axons and dendrites of RGCs is the basis for these cells to function as...
PURPOSE
Retinal ganglion cells (RGCs) connect the retina to the brain. Proper development of the axons and dendrites of RGCs is the basis for these cells to function as projection neurons to deliver visual information to the brain. The purpose of this study was to investigate the function of Shtn1 (which encodes shootin1) in RGC neurite development.
METHODS
Immunofluorescence (IF) was used to characterize the expression pattern of marker genes. An in vitro direct somatic cell reprogramming system was used to generate RGC-like neurons (iRGCs), which was subsequently used to study the function of Shtn1. Short-hairpin RNAs (shRNAs) were used to knock down Shtn1, and the coding sequence (CDS) of Shtn1 was used to overexpress the gene. Lentiviruses were used to deliver shRNAs or CDSs into iRGCs. The patch clamp technique was used to measure the electrophysiological properties of the iRGCs. RNA sequencing (RNA-seq) was used to examine transcriptome expression.
RESULTS
Using IF, we demonstrated that shootin1 is distinctively expressed in RGCs during the period in which RGCs actively develop and adjust the connections of their neurites with upstream and downstream neurons. Using the iRGC system, we demonstrated that Shtn1 promotes the growth and complexity of neurites and thus the electrophysiological maturation, of iRGCs. RNA-seq analyses showed that Shtn1 may also regulate gene expression and neurogenesis in iRGCs.
CONCLUSIONS
Shtn1 promotes RGC neurite development. These findings improve our understanding of the molecular machinery governing RGC neurite development and may help to optimize future RGC regeneration methods.
Topics: Retinal Ganglion Cells; Animals; Neurites; Mice; Nerve Tissue Proteins; Cellular Reprogramming; Cells, Cultured; Mice, Inbred C57BL; Patch-Clamp Techniques; Neurogenesis
PubMed: 38935030
DOI: 10.1167/iovs.65.6.41