Differences in collateral vessel formation after experimental retinal vein occlusion in spontaneously hypertensive rats and wild-type rats.

Objective: Retinal vein occlusion (RVO) can lead to visual impairment, but the development of collateral vessels can sometimes mitigate significant damage. This study aimed to investigate the relationship between collateral vessels and hypertension, the most common underlying condition associated with RVO, by comparing spontaneously hypertensive rats (SHRs) and wild-type Wister rats (WWRs). We also examined the differences between WWRs and SHRs in terms of sphingosine 1-phosphate receptor 1 (S1PR1) expression and its product nitric oxide synthase 3 (NOS3) expression, which are involved in the formation of collateral vessels after vascular occlusion. Methods: Laser photocoagulation (PC) was used to occlude one randomly selected retinal vein in WWRs and SHRs, and the area surrounding the occluded vessel was examined using optical coherence tomography angiography. If reperfusion of the occluded vessel occurred within 2 weeks, the vessel was re-occluded repeatedly by PC. The number of eyes with successfully occluded vessels accompanied by collateral vessels was recorded. Then, WWRs and SHRs were divided into the following four groups: 1) control (no treatment), 2) vehicle (20% DMSO), 3) S1PR1 agonist (2 mg/mL SEW2871), and 4) S1PR1 antagonist (0.25 mg/mL VPC 23019) groups. The drugs were administered intravitreally in all groups except the control. The number of laser shots required for successful RVO was recorded. Histological evaluation and quantitative real-time PCR of S1PR1 and NOS3 were performed to elucidate the mechanisms underlying collateral vessel formation. Results: The proportion of eyes achieving successful vein occlusion was lower in SHRs (4/12 eyes, 33.3%) than in WWRs (8/10 eyes, 80%, p = 0.043). NOS3 expression at 6 h after PC was significantly higher in WWRs than in SHRs (p = 0.021). In WWRs treated with SEW2871, vein occlusion failed in 7 of 10 eyes (70%). The expression of NOS3 was significantly higher in the SEW2871 treatment group than in the untreated group (p < 0.001). Furthermore, NOS3 expression was significantly higher after SEW2871 treatment in WWRs than in SHRs (p = 0.011). Conclusion: In hypertensive environments, collateral vessels are less likely to develop, and S1PR1 may be involved in this phenomenon.

16S rRNA nanopore sequencing for the diagnosis of ocular infection: a feasibility study.

OBJECTIVE: We conducted a feasibility study to verify the effectiveness of 16S ribosomal RNA (rRNA) gene analysis using the nanopore sequencer MinION for identifying causative bacteria in several types of ocular infections. METHODS AND ANALYSIS: Four cases of corneal ulcers, one case of endophthalmitis and one case of a conjunctival abscess were included in this study. DNA was extracted from corneal scraping, vitreous samples and secretions from the conjunctival abscess. We conducted 16S rRNA gene amplicon sequencing using MinION and metagenomic DNA analysis. The efficacy of bacterial identification was verified by comparing the conventional culture method with smear observations. RESULTS: 16S rRNA gene sequencing analysis with MinION identified the causative organisms promptly with high accuracy in approximately 4 hours, from ophthalmic specimens. The results of the conventional culture method and 16S rRNA gene sequencing were consistent in all cases. In four of the six cases, a greater variety of organisms was found in the 16S rRNA gene analysis than in bacterial culture. CONCLUSION: Using our workflow, 16S rRNA gene analysis using MinION enabled rapid and accurate identification possible in various kinds of bacterial ocular infections.

Aberrant Corneal Homeostasis in Neurosurgery-Induced Neurotrophic Keratopathy.

The characteristic features of neurotrophic keratopathy have been well documented by in vivo and in vitro studies using animal models. However, case reports of neurotrophic keratopathy induced by neurosurgery are limited. We describe the clinical characteristics, anterior segment optical coherence tomography (AS-OCT) and in vivo confocal microscopy (IVCM) findings of neurotrophic keratopathy induced by surgery for intracranial lesions. This is a case series including 6 eyes of 3 patients (mean age, 69.67 ± 12.50 years) with unilateral neurotrophic keratopathy. The clinical findings of three patients were described and IVCM findings of three patients were analyzed. The duration of neuropathy ranged from 2 to 30 years (median, 22 years). Thickening of the epithelial layer and higher reflection density of the anterior stroma were observed during the healing process using AS-OCT. The mean nerve fiber density of the subepithelial plexus, as determined by IVCM, was 1943 ± 1000 µm/mm2 for neurotrophic eyes and 2242 ± 600.3 µm/mm2 for contralateral eyes (p = 0.0347). The mean respective dendritic cell densities were 30.8 ± 21.8 and 6.25 ± 5.59 cells/mm2 (p < 0.0001), while the mean basal cell sizes were 259 ± 86.5 and 185 ± 45.9 µm2 (p < 0.0001), respectively. These findings suggest that neurosurgery-induced neurotrophic keratopathy may be associated with alterations in the healing process and immune cell distribution in the cornea.

Successful identification of Granulicatella adiacens in postoperative acute infectious endophthalmitis using a bacterial 16S ribosomal RNA gene-sequencing platform with MinION™: A case report.

Purpose: To evaluate the efficacy of identifying the bacteria by aqueous sampling and vitreous sampling in postoperative infectious endophthalmitis using 16S ribosomal RNA (rRNA) gene analysis with a nanopore sequencer (MinION™). Observation: A 55-year-old woman who underwent cataract surgery at an ophthalmology clinic 18 days ago was referred to our hospital for suspected endophthalmitis. She had light perception visual acuity in her right eye; however, the eye was severely inflamed, with a hypopyon and a fibrinous membrane in the anterior chamber. The fundus was not visible because of vitreous opacity on a B-scan image. Based on the diagnosis of postoperative acute infectious endophthalmitis, we performed a vitrectomy, intraocular lens extraction, and silicone oil tamponade. On postoperative day 14, the inflammation resolved. An aqueous sample was collected before surgical treatment, and the vitreous sample was collected during the operation. Both samples underwent 16S rRNA gene analysis with a nanopore sequencer MinION™ to identify the causative organism. Conclusions and Importance: In the aqueous humor, Granulicatella adiacens and Cutibacterium acnes were identified before the operation, while only Granulicatella adiacens was detected in the vitreous sample after the operation. Although the aqueous humor sample might contain commensal bacteria, it could provide a predictable result before the operation. It can also provide a substitute for a vitreous sample to allow earlier identification of the causative organism.

Time course of collateral vessel formation after retinal vein occlusion visualized by OCTA and elucidation of factors in their formation.

BACKGROUND: It is clinically recognized that collateral vessels can form after retinal vein occlusion (RVO) in some cases and these vessels can lead to spontaneous recovery of the pathological condition. In recent years, optical coherence tomography angiography (OCTA) has become a decisive clinical instrument. Unlike previous angiography tests, OCTA enables the non-invasive visualization of fundus vasculature without the need for administration of a contrast agent. However, it remains to be determined if OCTA depicts the 'true' histological status as several studies have reported artifacts in OCTA imaging. METHODS: We generated a laser-induced mouse RVO model, and evaluated the subsequent formation of collateral vessels in order to understand the mechanisms by which collateral vessels form using OCTA imaging, as well as molecular and histological assessments. RESULTS: We succeeded in visualizing the time course of collateral vessel formation in a mouse RVO model and confirmed the similarity in formation of collateral vessels only within the deep layer of the retina in both human and mouse. We hypothesized that sphingosine 1-phosphate receptor-1 (S1PR1) may play important roles via vascular shear stress linking vein occlusion and collateral vessel formation. Results from OCTA revealed that collateral vessels are increased in response to administration of a S1PR1 agonist in a mouse RVO model. Based on quantitative reverse transcription polymerase chain reaction (qRT-PCR), S1PR1 messenger ribonucleic acid (mRNA) levels in the whole retina peaked 6 h after photocoagulation in this model. Immunohistochemical staining of retinal flat mounts revealed that S1PR1 staining occurred along the laser-occluded blood vessels. CONCLUSION: We observed the temporal process of collateral vessel formation in a mouse RVO model and identified the relationship between S1PR1 and shear stress as one of the factors in collateral vessel formation in RVO.

Rapid eye movement sleep reveals epileptogenic spikes for resective surgery in children with generalized interictal discharges.

OBJECTIVE: Epilepsy surgery can be successful in children with extensive congenital or early acquired focal or hemispheric brain lesion on magnetic resonance imaging (MRI) despite generalized interictal epileptiform discharges (IEDs). The aim of this study was to assess if rapid eye movement (REM) sleep reduced generalized IEDs and revealed lateralized IEDs to identify the epileptogenic hemisphere in children with generalized IEDs and normal/subtle changes on MRI. METHODS: We studied 20 children with generalized IEDs on scalp electroencephalography (EEG) and normal/subtle changes on MRI who underwent intracranial video-EEG for epilepsy surgery. We assessed a minimum of 100 IEDs during REM, non-REM, and wakefulness, and assigned the distribution (generalized, left, or right hemisphere) to each IED. The number of lobes in the resected areas and seizure outcome were compared between 20 children with generalized IEDs and a comparison group of 28 children without generalized IEDs. RESULTS: The mean occurrence rate of generalized IEDs during REM (37%) was significantly lower than that during non-REM (67%, p < 0.001) and wakefulness (54%, p = 0.003). The number of children whose largest number of IEDs was lateralized in REM was significantly higher than that in non-REM (15 vs. 3 children, 75% vs. 15%, p < 0.001). The hemisphere with lateralized IEDs among three states corresponded with the surgical side in 16 children with generalized IEDs. Seventeen children (85%) with generalized IEDs and 27 (96%) without generalized IEDs underwent resective surgery. Multilobar resection was required for 16 children (94%) with generalized IEDs more frequently than 7 children (26%) without generalized IEDs (p < 0.001). Thirteen children (77%) with generalized IEDs and 19 (73%) without generalized IEDs were seizure-free with a mean of 3.3 years of follow-up. SIGNIFICANCE: Our study demonstrates the importance of assessing REM in children with generalized IEDs as it reveals lateralized epileptogenic spikes. Seizure freedom may be achieved with multilobar resection in these children with generalized IEDs and normal/subtle changes on MRI. Generalized IEDs in children with normal/subtle changes on MRI should not preclude surgical resection.