Acriflavine, a HIF-1 inhibitor, preserves vision in an experimental autoimmune encephalomyelitis model of optic neuritis.

Introduction: Optic neuritis (ON) is often an early sign of multiple sclerosis (MS), and recent studies show a link between HIF-1 pathway activation and inflammation. This study aimed to determine if inhibition of the HIF-1 pathway using the HIF-1a antagonist acriflavine (ACF) can reduce clinical progression and rescue the ocular phenotype in an experimental autoimmune encephalomyelitis (EAE) ON model. Methods: EAE-related ON was induced in 60 female C57BL/6J mice by immunization with MOG33-55, and 20 EAE mice received daily systemic injections of ACF at 5 mg/kg. Changes in the visual function and structure of ACF-treated EAE mice were compared to those of placebo-injected EAE mice and naïve control mice. Results: ACF treatment improved motor-sensory impairment along with preserving visual acuity and optic nerve function. Analysis of retinal ganglion cell complex alsoshowed preserved thickness correlating with increased survival of retinal ganglion cells and their axons. Optic nerve cell infiltration and magnitude of demyelination were decreased in ACF-treated EAE mice. Subsequent in vitro studies revealed improvements not only attributed to the inhibition of HIF-1 butalso to previously unappreciated interaction with the eIF2a/ATF4 axis in the unfolded protein response pathway. Discussion: This study suggests that ACF treatment is effective in an animal model of MS via its pleiotropic effects on the inhibition of HIF-1 and UPR signaling, and it may be a viable approach to promote rehabilitation in MS.

Immune responses in mice after blast-mediated traumatic brain injury TBI autonomously contribute to retinal ganglion cell dysfunction and death.

PURPOSE: The purpose of this study was to examine the role of the immune system and its influence on chronic retinal ganglion cell (RGC) dysfunction following blast-mediated traumatic brain injury (bTBI). METHODS: C57BL/6J and B6.129S7-Rag1tm1Mom/J (Rag-/-) mice were exposed to one blast injury of 140 kPa. A separate cohort of C57BL/6J mice was exposed to sham-blast. Four weeks following bTBI mice were euthanized, and splenocytes were collected. Adoptive transfer (AT) of splenocytes into naïve C57BL/6J recipient mice was accomplished via tail vein injection. Three groups of mice were analyzed: those receiving AT of splenocytes from C57BL/6J mice exposed to blast (AT-TBI), those receiving AT of splenocytes from C57BL/6J mice exposed to sham (AT-Sham), and those receiving AT of splenocytes from Rag-/- mice exposed to blast (AT-Rag-/-). The visual function of recipient mice was analyzed with the pattern electroretinogram (PERG), and the optomotor response (OMR). The structure of the retina was evaluated using optical coherence tomography (OCT), and histologically using BRN3A-antibody staining. RESULTS: Analysis of the PERG showed a decreased amplitude two months post-AT that persisted for the duration of the study in AT-TBI mice. We also observed a significant decrease in the retinal thickness of AT-TBI mice two months post-AT compared to sham, but not at four or six months post-AT. The OMR response was significantly decreased in AT-TBI mice 5- and 6-months post-AT. BRN3A staining showed a loss of RGCs in AT-TBI and AT-Rag-/- mice. CONCLUSION: These results suggest that the immune system contributes to chronic RGC dysfunction following bTBI.

Targeting Cholesterol Homeostasis Improves Recovery in Experimental Optic Neuritis.

Acute optic neuritis (ON) is a common cause of vision loss and is often associated with multiple sclerosis (MS). Cholesterol recycling has been identified as a key limiting factor in recovery after demyelination events. Thus, the purpose of our study was to determine if the augmentation of cholesterol transport by gentisic acid (GA) benefits retinal ganglion cell (RGC) development and myelination in organoid systems and enables the recovery of the ocular phenotype upon systemic GA treatment in a MOG-induced experimental autoimmune encephalomyelitis (EAE) ON model. The retinal organoids treated with GA demonstrate an accelerated maturation when compared to the conventionally derived organoids, which was evidenced by the improved organization of Brn3a-GFP+RGC and increased synaptogenesis. A GA supplementation in brain organoids leads to a 10-fold increase in NG2 and Olig2 expression. Weekly GA injections of EAE mice significantly lessened motor-sensory impairment, protected amplitudes in pattern electroretinogram recordings, and preserved visual acuity over the study period of 56 days. Furthermore, GA-treated EAE mice revealed diminished GCL/IPL complex thinning when compared to the untreated EAE mice. An optic nerve histopathology revealed less severe grades of demyelination in the GA-treated EAE cohort and fewer infiltrating cells were observed. Interventions to improve cholesterol homeostasis may be a viable approach to promoting the rehabilitation of MS patients.

Systemic Treatment with Pioglitazone Reverses Vision Loss in Preclinical Glaucoma Models.

Neuroinflammation significantly contributes to the pathophysiology of several neurodegenerative diseases. This is also the case in glaucoma and may be a reason why many patients suffer from progressive vision loss despite maximal reduction in intraocular pressure. Pioglitazone is an agonist of the peroxisome proliferator-activated receptor gamma (PPARγ) whose pleiotrophic activities include modulation of cellular energy metabolism and reduction in inflammation. In this study we employed the DBA2/J mouse model of glaucoma with chronically elevated intraocular pressure to investigate whether oral low-dose pioglitazone treatment preserves retinal ganglion cell (RGC) survival. We then used an inducible glaucoma model in C57BL/6J mice to determine visual function, pattern electroretinographs, and tracking of optokinetic reflex. Our findings demonstrate that pioglitazone treatment does significantly protect RGCs and prevents axonal degeneration in the glaucomatous retina. Furthermore, treatment preserves and partially reverses vision loss in spite of continuously elevated intraocular pressure. These data suggest that pioglitazone may provide treatment benefits for those glaucoma patients experiencing continued vision loss.

Comparison of Fine Arts- and Pathology-Based Observational Skills Training for Veterinary Students Learning Cytology.

Keen observational skills are essential for veterinarians; however, the development of these skills is not usually an explicit part of the veterinary curriculum. Fine arts-based (FAB) observation training has been shown to improve medical students' observational skills and might also improve veterinary students' observational skills. We compared FAB and pathology-based (PB) observation training in a veterinary cytology course. Students initially wrote a pre-test in which they described two cytology images and one art image, followed by participation in either FAB or PB observation training. Both groups completed a similar post-test immediately after training and a delayed post-test 4 weeks later following instruction in cytology. Differences between groups were noted only in the immediate post-test cytology descriptions. The PB group used significantly more specific vocabulary terms and significantly more accurate observations than the FAB group, suggesting an immediate benefit to the discipline-specific information gained in the PB observation training. In the delayed post-test, results for both groups were similar. The FAB group significantly increased their use of specific vocabulary terms and maintained but did not increase accurate observations following cytology instruction, while accurate observations decreased significantly for the PB group. The FAB group might have been able to generalize their observation skills to the discipline of cytology and to better retain these skills. Neither type of training resulted in both achievement and maintenance of the highest recorded scores for accurate observations. Both FAB and PB training led to improved observational skills, and explicit observation training may be useful for veterinary students.

Early Functional Impairment in Experimental Glaucoma Is Accompanied by Disruption of the GABAergic System and Inceptive Neuroinflammation.

Glaucoma is a leading cause of irreversible blindness worldwide, and increased intraocular pressure (IOP) is a major risk factor. We aimed to determine if early functional and molecular differences in the glaucomatous retina manifest before significant retinal ganglion cell (RGC) loss is apparent. Adenoviral vectors expressing a pathogenic form of myocilin (Ad5.MYOC) were used to induce IOP elevation in C57BL/6 mice. IOP and pattern electroretinograms (pERG) were recorded, and retinas were prepared for RNA sequencing, immunohistochemistry, or to determine RGC loss. Ocular injection of Ad5.MYOC leads to reliable IOP elevation, resulting in significant loss of RGC after nine weeks. A significant decrease in the pERG amplitude was evident in eyes three weeks after IOP elevation. Retinal gene expression analysis revealed increased expression for 291 genes related to complement cascade, inflammation, and antigen presentation in hypertensive eyes. Decreased expression was found for 378 genes associated with the γ-aminobutyric acid (GABA)ergic and glutamatergic systems and axon guidance. These data suggest that early functional changes in RGC might be due to reduced GABAA receptor signaling and neuroinflammation that precedes RGC loss in this glaucoma model. These initial changes may offer new targets for early detection of glaucoma and the development of new interventions.

Using Fine Arts-Based Training to Develop Observational Skills in Veterinary Students Learning Cytology: A Pilot Study.

Arts-based training has been shown to improve medical students' observational skills. Veterinarians also need keen observational skills. Student veterinarians are expected to develop their observational skills; however, this training is usually not an explicit part of the veterinary curriculum. The impact of arts-based observation training has not been investigated in veterinary students learning cytology. In this pilot study, we compared student descriptions of art and cytology images before and immediately after receiving arts-based observation training. After 10 hours of cytology instruction, we again tested students' observational skills and asked for feedback via a survey. Pre-tests and post-tests were scored following a rubric based on expert descriptions of the images. Scores for art image descriptions were higher for both the immediate and delayed post-tests compared to the pre-test (p < .05). Scores for cytology image descriptions were higher for the immediate post-test than the pre-test, but this difference was not significant. Despite 10 hours of cytology instruction between post-tests, scores for cytology image descriptions were lower for the delayed post-test than the immediate post-test, but again, this difference was not significant. Student feedback on the arts-based observation training was positive. Overall, our results suggest that arts-based training may improve student observational skills, although context could be important, as the improvement in description was only significant for art images. Further investigation with a larger cohort of students and a control group that does not receive arts-based training would be valuable.