"More Guts Than Brains?"-The Role of Gut Microbiota in Idiopathic Intracranial Hypertension.

BACKGROUND: Idiopathic intracranial hypertension syndrome (IIH) is most common among obese women. Weight loss is an important factor in improving papilledema. Over the last decade, growing evidence has identified gut microbiota as a potential factor in the pathophysiology of obesity. Accordingly, we investigated whether the gut microbiome is modified in IIH patients compared with healthy controls, and provide possible new treatment venues. METHODS: Shotgun metagenomic sequencing of the gut microbiome of 25 cases of IIH patients (according to the modified Dandy criteria) and 20 healthy controls. Participants were further stratified according to their body mass index. The total DNA from each sample was extracted using the PureLink Microbiome DNA Purification Kit A29789 (Invitrogen, Thermo Fisher Scientific, US). Library preparation was performed using the Nextera DNA Flex Library Prep Kit. Samples were sequenced on the Illumina Novaseq 6000 device. A list of bacterial species that significantly differed between the IIH patients and healthy controls was produced in addition to species diversity. In addition, patients' cohort alone was analyzed, (excluding the healthy controls), and the effect of acetazolamide treatment on their gut microbiota was analyzed. RESULTS: IIH patients have a lower diversity of bacterial species compared with healthy individuals. These bacteria, that is, Lactobacillus ruminis (L. ruminis) (p<6.95E-08), Atopobium parvulum (p<3.9E-03), Megamonas hypermegale (p<5.61E-03), Ruminococcus gnavus (p<1.29E-02), MEL.A1 (p<3.04E-02), and Streptococcus sp. I-G2 (p<3.04E-02), were previously characterized with beneficial health effects. Moreover, we found that Lactobacillus brevis, a beneficial bacterium as well, is more abundant in acetazolamide treated patients (p<7.07E-06). CONCLUSIONS: Gut microbiota plays a potential role in IIH etiology and therefore, can provide a promising new treatment approach for this disease.

SOX2 Regulates P63 and Stem/Progenitor Cell State in the Corneal Epithelium.

Mutations in key transcription factors SOX2 and P63 were linked with developmental defects and postnatal abnormalities such as corneal opacification, neovascularization, and blindness. The latter phenotypes suggest that SOX2 and P63 may be involved in corneal epithelial regeneration. Although P63 has been shown to be a key regulator of limbal stem cells, the expression pattern and function of SOX2 in the adult cornea remained unclear. Here, we show that SOX2 regulates P63 to control corneal epithelial stem/progenitor cell function. SOX2 and P63 were co-expressed in the stem/progenitor cell compartments of the murine cornea in vivo and in undifferentiated human limbal epithelial stem/progenitor cells in vitro. In line, a new consensus site that allows SOX2-mediated regulation of P63 enhancer was identified while repression of SOX2 reduced P63 expression, suggesting that SOX2 is upstream to P63. Importantly, knockdown of SOX2 significantly attenuated cell proliferation, long-term colony-forming potential of stem/progenitor cells, and induced robust cell differentiation. However, this effect was reverted by forced expression of P63, suggesting that SOX2 acts, at least in part, through P63. Finally, miR-450b was identified as a direct repressor of SOX2 that was required for SOX2/P63 downregulation and cell differentiation. Altogether, we propose that SOX2/P63 pathway is an essential regulator of corneal stem/progenitor cells while mutations in SOX2 or P63 may disrupt epithelial regeneration, leading to loss of corneal transparency and blindness. Stem Cells 2019;37:417-429.

A novel intronic mutation of PDE6B is a major cause of autosomal recessive retinitis pigmentosa among Caucasus Jews.

Purpose: To identify the genetic basis for retinitis pigmentosa (RP) in a cohort of Jewish patients from Caucasia. Methods: Patients underwent a detailed ophthalmic evaluation, including funduscopic examination, visual field testing, optical coherence tomography (OCT), and electrophysiological tests, electroretinography (ERG) and visual evoked potentials (VEP). Genetic analysis was performed with a combination of whole exome sequencing (WES) and Sanger sequencing. Bioinformatic analysis of the WES results was performed via a customized pipeline. Pathogenicity of the identified intronic variant was evaluated in silico using the web tool Human Splicing Finder, and in vitro, using a minigene-based splicing assay. Linkage disequilibrium (LD) analysis was used to demonstrate a founder effect, and the decay of LD over generations around the mutation in Caucasus Jewish chromosomes was modeled to estimate the age of the most recent common ancestor. Results: In eight patients with RP from six unrelated families, all of Caucasus Jewish ancestry, we identified a novel homozygous intronic variant, located at position -9 of PDE6B intron 15. The c.1921-9C>G variant was predicted to generate a novel acceptor splice site, nine bases upstream of the original splice site of intron 15. In vitro splicing assay demonstrated that this novel acceptor splice site is used instead of the wild-type site, leading to an 8-bp insertion into exon 16, which is predicted to cause a frameshift. The presence of a common ancestral haplotype in mutation-bearing chromosomes was compatible with a founder effect. Conclusions: The PDE6B c.1921-9C>G intronic mutation is a founder mutation that accounts for at least 40% (6/15 families) of autosomal recessive RP among Caucasus Jews. This result is highly important for molecular diagnosis, carrier screening, and genetic counseling in this population.

[WHEN IT SNOWS ALL YEAR ROUND - VISUAL SNOW].

INTRODUCTION: Visual snow is a neurological condition manifested as a prolonged visual experience of small flickering dots encompassing the entire visual field with additional visual and sensory-neural symptoms. The pathogenesis of this disturbance is unknown, although much progress has been made in recent years. The disturbance has been better defined and characterized. Additional insight into the pathological processes that play a role in this phenomenon has been gained, and different treatment modalities have been tried, some with better results. The purpose of this review is to increase awareness of this syndrome.

[MINIMALLY INVASIVE GLAUCOMA SURGERIES].

INTRODUCTION: The goal of all glaucoma surgery is to lower eye pressure to prevent or reduce damage to the optic nerve. Standard glaucoma surgeries - trabeculectomy, ExPRESS shunts and external tube-shunts like the Ahmed and Baerveldt valves - are major surgeries. While they are very often effective at lowering eye pressure and preventing progression of glaucoma, they have a long list of potential complications. Minimal invasive glaucoma surgery (MIGS) is a group of operations that have been developed in recent years to reduce some of the complications of most standard glaucoma surgeries. MIGS procedures work by using microscopic-sized equipment and tiny incisions. The purpose of this study is to review the available MIGS currently in use, their benefits and limitations.

Lineage tracing of stem and progenitor cells of the murine corneal epithelium.

Accumulating evidence supports the dogma that the corneal epithelium is regenerated by stem cells located exclusively in the limbal niche, at the corneal periphery. Accordingly, limbal stem cells (LSCs) give rise to progenitors that proliferate and migrate centripetally to repopulate the corneal epithelium, which has a short turnover. Moreover, LSC loss leads to corneal opacity and blindness, while limbal grafting restores patients' vision. However, contradicting data suggested that the limbus does not participate in corneal homeostasis and that the cornea contains stem cells. As of today, only indirect evidence for limbal cell migration under homeostasis or injury has been demonstrated. Here, we performed lineage tracing experiments using R26R-Confetti mice to follow K14+ limbal/corneal epithelial cells stochastically induced to express one out of four fluorescent genes. In homeostasis, radial limbal stripes of slow migrating cells proceeded toward the corneal center while, infrequently, slow cycling limbal clones resembling quiescent stem cells were observed. Additionally, rare corneal clones that did not migrate centripetally, but survived for over 4 months, were inspected. In contrast to limbal stripes, corneal clusters had minor contribution to tissue replenishment in homeostasis. Corneal cells, however, significantly contributed to mild wound repair while large limbal streaks appeared within a week following severe wounding that coincided with partial loss of corneal transparency. This data suggest that the mouse limbus largely contributes to corneal renewal while corneal progenitor cells have a long turnover and, therefore, may be able to maintain the corneal epithelium for several months.

A genetic survey of patients with familial idiopathic intracranial hypertension residing in a Middle Eastern village: genetic association study.

BACKGROUND: The aim of this study was to determine whether genetic variants are associated with idiopathic intracranial hypertension (IIH) in a unique village where many of the IIH patients have familial ties, a homogenous population and a high prevalence of consanguinity. Several autosomal recessive disorders are common in this village and its population is considered at a high risk for genetic disorders. METHODS: The samples were genotyped by the Ilumina OmniExpress-24 Kit, and analyzed by the Eagle V2.4 and DASH software package to cluster haplotypes shared between our cohort. Subsequently, we searched for specific haplotypes that were significantly associated with the patient groups. RESULTS: Fourteen patients and 30 controls were included. Samples from 22 female participants (11 patients and 11 controls) were evaluated for haplotype clustering and genome-wide association studies (GWAS). A total of 710,000 single nucleotide polymorphisms (SNPs) were evaluated. Candidate areas positively associated with IIH included genes located on chromosomes 16, 8 (including the CA5A and BANP genes, p < 0.01), and negatively associated with genes located on chromosomes 1 and 6 (including PBX1, LMX1A, ESR1 genes, p < 0.01). CONCLUSIONS: We discovered new loci possibly associated with IIH by employing a GWAS technique to estimate the associations with haplotypes instead of specific SNPs. This method can in all probability be used in cases where there is a limited amount of samples but strong familial connections. Several loci were identified that might be strong candidates for follow-up studies in other well-phenotypes cohorts.

XEN45 Gel Stent Combined with Healaflow Injectable Viscoelastic Implant.

Purpose: To introduce a potential solution for failed glaucoma surgeries by proposing an optional surgical procedure in conjunction with the use of Healaflow (Anteis S.A., Geneva, Switzerland) as a spacer, which may potentially reduce the failure rate. Case Presentation. We present the outcomes of a surgical procedure involving the inferonasal implantation of an ab interno XEN gel stent (Allergan, Dublin, Ireland) in a 74-year-old male patient who was experiencing uncontrolled advanced glaucoma in his left eye. It is important to note that the patient had previously undergone several glaucoma surgeries and procedures in the same eye. During this particular procedure, we utilized Healaflow as a spacer by implanting the stent within a subconjunctival Healaflow "bubble." At 6 months postoperatively, intraocular pressure remained on target. There was no need for additional topical medications, and no change in visual acuity was observed. Conclusion: For patients with a history of unsuccessful glaucoma surgeries and who are unsuitable candidates for tube shunt procedures or transscleral diode cyclophotocoagulation, an alternative option involves implanting the XEN45 stent in the inferior nasal region in conjunction with the use of subconjunctival Healaflow. This combined approach may provide a potential solution for managing glaucoma in these patients.

Eyes open on stem cells.

Recently, the murine cornea has reemerged as a robust stem cell (SC) model, allowing individual SC tracing in living animals. The cornea has pioneered seminal discoveries in SC biology and regenerative medicine, from the first corneal transplantation in 1905 to the identification of limbal SCs and their transplantation to successfully restore vision in the early 1990s. Recent experiments have exposed unexpected properties attributed to SCs and progenitors and revealed flexibility in the differentiation program and a key role for the SC niche. Here, we discuss the limbal SC model and its broader relevance to other tissues, disease, and therapy.

The biophysical property of the limbal niche maintains stemness through YAP.

The cell fate decisions of stem cells (SCs) largely depend on signals from their microenvironment (niche). However, very little is known about how biochemical niche cues control cell behavior in vivo. To address this question, we focused on the corneal epithelial SC model in which the SC niche, known as the limbus, is spatially segregated from the differentiation compartment. We report that the unique biomechanical property of the limbus supports the nuclear localization and function of Yes-associated protein (YAP), a putative mediator of the mechanotransduction pathway. Perturbation of tissue stiffness or YAP activity affects SC function as well as tissue integrity under homeostasis and significantly inhibited the regeneration of the SC population following SC depletion. In vitro experiments revealed that substrates with the rigidity of the corneal differentiation compartment inhibit nuclear YAP localization and induce differentiation, a mechanism that is mediated by the TGFß-SMAD2/3 pathway. Taken together, these results indicate that SC sense biomechanical niche signals and that manipulation of mechano-sensory machinery or its downstream biochemical output may bear fruits in SC expansion for regenerative therapy.

Efficacy of the XEN45 Implant in Advanced to End-stage Glaucoma Patients.

Purpose: To report the efficacy of the XEN45 implant in advanced to end-stage glaucoma patients, after a 6 months follow-up. Methods: Retrospective, noncomparative electronic health record audit of patients who had undergone an XEN45 procedure. The main outcome measures were intraocular pressure (IOP) reduction and the number of antihypertensive medications. Secondary outcome measures were the rates of early postoperative complications. Complete and qualified success; failure and hypotony were defined according to the World Glaucoma Association guidelines (Shaarawy TM et al.). Needling rates and short-term complications were assessed and a subgroup analysis was performed. Results: A total of 39 eyes with advanced to end stage-glaucoma were included. Twenty eyes (51%) had undergone combined cataract surgery and 19 (49%), the XEN45 procedure alone. Mean IOP decreased from 19.67 ± 7.87 mm Hg to 13.18 ± 6.09 mm Hg; the number of medications decreased from a median use of 4 (IQR 2-5) to 0 (IQR 0-1). Complete success was achieved in 24 (61.5%) of the eyes, qualified success in 10 (25.6%), and failure in five (12.82%). Needling was required in 15 (38.46%) of the eyes at 6 months. Choroidal detachment occurred in eight (20.51%) eyes, numerical hypotony (IOP ≤ 5 mm Hg) at day 1 was noted in seven (17.95%) eyes with a full resolution by 2 weeks. Conclusion: In this short-term follow-up, we have seen that XEN45 is a viable, effective, and safe procedure utilized in advanced to end-stage glaucoma patients. Treating cases of significant hypotony using AC reformation with sulfur hexafluoride (SF6) is a safe and effective procedure. How to cite this article: Hindi I, Berkowitz E, Waizer I, et al. Efficacy of the XEN45 Implant in Advanced to End-stage Glaucoma Patients. J Curr Glaucoma Pract 2022;16(2):84-90.

Neovascular Glaucoma as a Presenting Sign of Catastrophic Antiphospholipid Syndrome with a "Catastrophic" Heart Valve Finding.

We aimed to describe a case of neovascular glaucoma (NVG) as a first presenting sign of catastrophic antiphospholipid syndrome (CAPS) with heart valve aseptic vegetations known as Libman-Sacks endocarditis. A 39-year-old man was referred for left eye decreased visual acuity and pain, upon examination left eye high intraocular pressure; rubeosis iridis of both eyes (BE); and prominent retinal ischemia. Clinical and fluorescein angiography findings established the diagnosis of left eye NVG with vaso-occlusive disease in BE. Magnetic resonance imaging of the head showed widespread ischemic lesions and hemorrhagic foci. The transesophageal echocardiogram showed 2 big mitral valve lesions consistent with the diagnosis of Libman-Sacks endocarditis. Laboratory and clinical diagnosis of CAPS and suspected SLE was confirmed, and treatment with anticoagulants and IV steroids was initiated. This case demonstrates that severe vaso-occlusive retinopathy with severe brain ischemia should raise the suspicion of systemic autoimmune pro-coagulative diseases with heart valve aseptic vegetations.

Discrete limbal epithelial stem cell populations mediate corneal homeostasis and wound healing.

The accessibility and transparency of the cornea permit robust stem cell labeling and in vivo cell fate mapping. Limbal epithelial stem cells (LSCs) that renew the cornea are traditionally viewed as rare, slow-cycling cells that follow deterministic rules dictating their self-renewal or differentiation. Here, we combined single-cell RNA sequencing and advanced quantitative lineage tracing for in-depth analysis of the murine limbal epithelium. These analysis revealed the co-existence of two LSC populations localized in separate and well-defined sub-compartments, termed the "outer" and "inner" limbus. The primitive population of quiescent outer LSCs participates in wound healing and boundary formation, and these cells are regulated by T cells, which serve as a niche. In contrast, the inner peri-corneal limbus hosts active LSCs that maintain corneal epithelial homeostasis. Quantitative analyses suggest that LSC populations are abundant, following stochastic rules and neutral drift dynamics. Together these results demonstrate that discrete LSC populations mediate corneal homeostasis and regeneration.

Visual Snow: A Case Series from Israel.

Our aim was to examine the symptoms and clinical characteristics of visual snow in a group of 6 patients from a Department of Ophthalmology and a Department of Neurology. Visual snow is now recognized as a true physiological disorder. Previously, physicians unaware of this syndrome may have misinterpreted its symptoms as a persistent visual aura. By promoting awareness of this syndrome, greater quantitative and qualitative research may expand our understanding and treatment of this disorder.

Short-term anterior chamber inflammation in phacoemulsification with and without Ex-Press glaucoma implant.

PURPOSE: The aim of this study was to investigate the incidence of clinically significant anterior chamber inflammation in a combined surgery, namely, phacoemulsification and Ex-Press miniature glaucoma device implantation, compared to phacoemulsification alone. METHODS: A retrospective comparative study of a consecutive series of 210 participants above 18 years of age diagnosed with significant cataract and who required glaucoma surgery, namely, Ex-Press miniature glaucoma device implantation or cataract alone in one or both eyes. All were operated on by a single experienced glaucoma surgeon in a single medical center. A total of 231 eyes were included in this study. All cases underwent an uneventful surgery and were examined the day following the surgery for visual acuity, intraocular pressure, and signs of excessive anterior chamber inflammation (Standardization of Uveitis Nomenclature grading ⩾ 3). RESULTS: The combined group included 55 eyes of 51 patients, of whom 15 (27.3%) demonstrated excessive anterior chamber inflammation. The phacoemulsification group included 176 eyes of 159 patients, of whom 12 (6.7%) demonstrated excessive anterior chamber inflammation. Visual acuity and intraocular pressure measurements showed no statistically significant difference between the two groups. CONCLUSION: The Ex-Press glaucoma device is efficient, safe, and known for its inert nature. However, combination of this procedure with phacoemulsification surgery might result in a condition encouraging excessive inflammation, which eventually could lead to excessive anterior chamber inflammations if not treated vigorously. Emphasizing and recognizing the risks, especially in glaucoma patients, is important.

Corneal Perforation after Nd: YAG Capsulotomy: A Case Report and Literature Review.

BACKGROUND: Nd: YAG capsulotomy is the treatment of choice for posterior capsular opacification after cataract surgery. We report a case of corneal perforation following Nd:YAG capsulotomy in a patient with systemic scleroderma. CASE PRESENTATION: A 69-year-old woman presented with acute onset of blurred vision 2 weeks following Nd:YAG laser capsulotomy for posterior subcapsular opacification. On examination, her best-corrected visual acuity was 1/120, and bio-microscopy revealed a central full-thickness corneal laceration. Conservative treatment consisted of topical ocular antibiotics, cycloplegics, hypotensive drops and a soft therapeutic contact lens. Her final visual acuity improved to 6/18 with resolution of the corneal laceration. CONCLUSION: The possibility of corneal perforation after Nd-YAG capsulotomy in patients with systemic scleroderma and connective tissue disease should be borne in mind when treating such patients.

Clinical Efficacy and Safety of the EX-PRESS Filtration Device in Patients with Advanced Neovascular Glaucoma and Proliferative Diabetic Retinopathy.

BACKGROUND: The prognosis of conventional filtration surgery in eyes with neovascular glaucoma (NVG) is limited due to increased fibrovascular proliferation or bleeding. This study aims to evaluate the safety and efficacy of the EX-PRESS filtration device in the management of NVG associated with proliferative diabetic retinopathy (PDR). METHODS: In this retrospective case series, we reviewed the medical records of patients diagnosed as having NVG associated with PDR who underwent EX-PRESS filtration surgery. The main outcome measures were: postoperative intraocular pressure (IOP), the percent of IOP drop, the number of glaucoma medications, visual acuity, and complications of surgery. Successful surgery was defined as an IOP <22 mm Hg and >5 mm Hg with or without additional glaucoma surgery, and no loss of light perception or less than a 2-line decrease on the Snellen chart of the best corrected visual acuity (BCVA). RESULTS: Five patients (5 eyes) were included in this study. The mean preoperative IOP was 33.4 ± 5.9 mm Hg compared to an IOP of 17.0 ± 3.0 mm Hg at the last follow-up (p = 0.003). The mean number of preoperative anti-glaucoma medications was 3.8 ± 0.4 compared to 2.2 ± 1.5 (p = 0.06) at the last follow-up visit. Final visual acuity improved or stabilized within 1 Snellen line in all 5 patients. Three patients had a "hypertensive phase" (defined as an IOP >21 mm Hg during the first 6 postoperative months) which resolved within 2 months. Two patients developed a hyphema that resolved spontaneously. None of the patients experienced any serious complications. CONCLUSION: EX-PRESS filtration device has a good IOP-lowering effect and a low rate of complications in patients with advanced NVG associated with PDR. In addition, there was no loss of light perception or no line decrease of the BCVA.

Corneal-Committed Cells Restore the Stem Cell Pool and Tissue Boundary following Injury.

During morphogenesis, preserving tissue boundaries is essential for cell fate regulation. While embryonic tissues possess high plasticity and repair ability, the questions of whether and how adult tissues cope with acute stem cell (SC) loss or boundary disruption have remained unanswered. Here, we report that K15-GFP transgene labels the murine corneal epithelial boundary and SC niche known as the limbus. K15-GFP+ basal cells expressed SC markers and were located at the corneal regeneration site, as evident by lineage tracing. Remarkably, following surgical deletion of the SC pool, corneal-committed cells dedifferentiated into bona fide limbal SCs that retained normal tissue dynamics and marker expression. Interestingly, however, damage to the limbal stromal niche abolished K15-GFP recovery and led to pathological wound healing. Altogether, this study indicates that committed corneal cells possess plasticity to dedifferentiate, repopulate the SC pool, and correctly re-form the tissue boundary in the presence of intact stroma.

IgG4-Related Disease Presenting as Isolated Scleritis.

A rare case of IgG4-related disease (IgG4-RD) manifesting as nodular scleritis is presented in a 20-year-old female. Patient complained of left eye pain and redness for one week. Ocular examination together with ancillary testing led to the diagnosis of nodular scleritis. Since the patient did not show apparent improvement after one week of systemic steroidal treatment, she underwent a biopsy of the affected area revealing histopathological characteristics of IgG4-RD. Long-term treatment with corticosteroids and a steroid-sparing agent (methotrexate) led to significant improvement in signs and symptoms. This case highlights the significance of IgG4-RD in the differential diagnosis of scleritis and raises the question as to whether various organs affected by IgG4-RD may have different underlying pathophysiological mechanisms in which pathogenic T cells play a role.

Oculopharyngeal Muscular Dystrophy and Inherited Retinal Dystrophy in Bukhara Jews Due to Linked Mutations in the PABPN1 and NRL Genes.

AIM: We have previously described two unrelated Bukhara Jews (BJs) with a combination of oculopharyngeal muscular dystrophy (OPMD) and inherited retinal dystrophy (IRD), because of mutations in two linked genes: PABPN1 and NRL. Here we investigated the prevalence of the NRL mutation among BJs with OPMD. MATERIALS AND METHODS: PABPN1 and NRL mutation testing were performed by polymerase chain reaction amplification and direct sequencing on two cohorts of Bukhara Jewish patients: OPMD patients (with or without IRD) and IRD patients (without OPMD). RESULTS: Of 24 unrelated chromosomes from Bukhara Jewish OPMD patients, 19 (79%) harbored the NRL mutation. In contrast, the NRL mutation was not detected in Bukhara Jewish patients diagnosed with IRD but without OPMD. CONCLUSIONS: Our findings provide an explanation for the reoccurrence of IRD in Bukhara Jewish OPMD homozygotes. Moreover, they indicate that Bukhara Jewish OPMD patients are at high risk for carrying the NRL mutation, and should be offered appropriate genetic counseling and testing.