The inability of neurons to regenerate long axons within the CNS is a major impediment to improving outcome after spinal cord injury, stroke, and other CNS insults. Recent advances have uncovered an intrinsic program that involves coordinate regulation by multiple transcription factors that can be manipulated to enhance growth in the peripheral nervous system. Here, we use a systems genomics approach to characterize regulatory relationships of regeneration-associated transcription factors, identifying RE1-Silencing Transcription Factor (REST; Neuron-Restrictive Silencer Factor, NRSF) as a predicted upstream suppressor of a pro-regenerative gene program associated with axon regeneration in the CNS. We validate our predictions using multiple paradigms, showing that mature mice bearing cell type-specific deletions of REST or expressing dominant-negative mutant REST show improved regeneration of the corticospinal tract and optic nerve after spinal cord injury and optic nerve crush, which is accompanied by upregulation of regeneration-associated genes in cortical motor neurons and retinal ganglion cells, respectively. These analyses identify a role for REST as an upstream suppressor of the intrinsic regenerative program in the CNS and demonstrate the utility of a systems biology approach involving integrative genomics and bio-informatics to prioritize hypotheses relevant to CNS repair.
Neurodegenerative diseases affect millions of people worldwide. Optic neuropathies are the most commonly occurring neurodegenerative diseases, characterized by progressive retinal ganglion cell (RGC) degeneration. We recently reported that Prominin-1, a protein found on the surface of stem cells, interacts with VEGF and enhances its activity. VEGF is known to have various protective roles in the nervous system. Subsequently, we have developed a 12-mer peptide derived from Prominin-1, named PR1P, and investigated its effects on neuronal survival of damaged RGCs in a rat model of optic nerve crush (ONC). PR1P prevented RGC apoptosis resulting in improvement of retinal function in the rat ONC model. PR1P treatment significantly increased phosphorylation of ERK and AKT and expression its downstream proteins c-fos and Egr-1 in the retina. Additionally, PR1P beneficially increased the MMP-9/TIMP-1 ratio and promoted glial activation in the retina of ONC rats. Thus, PR1P displayed neuroprotective effects through enhanced VEGF-driven neuronal survival and reconstruction of the extracellular environment in ONC model. Our data indicate that PR1P may be a promising new clinical candidate for the treatment of neurodegenerative diseases.
PURPOSE OF REVIEW: Myelin oligodendrocyte glycoprotein (MOG)-IgG-associated optic neuritis has been established as a new entity of optic neuropathy. We will review recent advances in pathophysiology, diagnosis, and clinical manifestations of MOG-IgG-associated optic neuritis to better understand its distinctive characteristics. RECENT FINDINGS: MOG is expressed on the surface of myelin sheaths and oligodendrocytes. MOG is highly immunogenic and is a potential target of inflammatory demyelinating disease. MOG-IgG activate immune responses and cause demyelination without astrocytopathy. MOG-IgG are measured by cell-based assays, which have higher sensitivity and specificity than ELISA. Patients with MOG-IgG-associated optic neuritis present with initially severe vision loss, are more likely to have optic disc edema, but have favorable visual outcomes. Furthermore, patients with MOG-IgG-associated optic neuritis have higher rates of recurrence compared with MOG-IgG seronegative patients. MOG-IgG-associated optic neuritis responds well to steroid treatment, however, close monitoring for signs of relapse and long-term immunosuppression may be necessary. SUMMARY: MOG-IgG associated optic neuritis demonstrates distinctive pathophysiological and clinical characteristics from optic neuritis in aquaporin4-IgG seropositive or multiple sclerosis patients. Measurements of MOG-IgG titers by cell-based assays will be helpful for the diagnosis and treatment of optic neuritis.
PURPOSE OF REVIEW: Recent advances in experimental studies of optic nerve regeneration to better understand the pathophysiology of axon regrowth and provide insights into the future treatment of numerous optic neuropathies. RECENT FINDINGS: The optic nerve is part of the central nervous system and cannot regenerate if injured. There are several steps that regenerating axons of retinal ganglion cells (RGCs) must take following optic nerve injury that include: maximizing the intrinsic growth capacity of RGCs, overcoming the extrinsic growth-inhibitory environment of the optic nerve, and optimizing the reinnervation of regenerated axons to their targets in the brain. Recently, some degree of experimental optic nerve regeneration has been achieved by factors associated with inducing intraocular inflammation, providing exogenous neurotrophic factors, reactivating intrinsic growth capacity of mature RGCs, or by modifying the extrinsic growth-inhibitory environment of the optic nerve. In some experiments, regenerating axons have been shown to reinnervate their central targets in the brain. SUMMARY: Further approaches to the combination of aforementioned treatments will be necessary to develop future therapeutic strategy to promote ultimate regeneration of the optic nerve and functional vision recovery after optic nerve injury.
PURPOSE OF REVIEW: Review recent advances in clinical and experimental studies of dominant optic atrophy (DOA) to better understand the complexities of pathophysiology caused by the optic atrophy 1 (OPA1) mutation. RECENT FINDINGS: DOA is the most commonly diagnosed inherited optic atrophy, causing progressive bilateral visual loss that begins early in life. During the past 25 years, there has been substantial progress in the understanding of the clinical, genetic, and pathophysiological basis of this disease. The histopathological hallmark of DOA is the primary degeneration of retinal ganglion cells, preferentially in the papillomacular bundle, which results temporal optic disc pallor and cecocentral scotomata in patients with DOA. Loss of OPA1 protein function by OPA1 gene mutations causes mitochondrial dysfunction because of the loss of mitochondrial fusion, impaired mitochondrial oxidative phosphorylation, increases in reactive oxygen species, and altered calcium homeostasis. These factors lead to apoptosis of retinal ganglion cells by a haploinsufficiency mechanism. SUMMARY: Improved understanding of the pathophysiology of DOA provides insights that can be used to develop therapeutic approaches to the DOA.
PURPOSE OF REVIEW: We review new applications of optical coherence tomography (OCT) technology in neuro-ophthalmology. We also describe new technologies for visualizing the extracranial vessels in the diagnosis of giant cell arteritis (GCA). RECENT FINDINGS: Newer OCT modalities are expanding the evaluation of the optic disc, and are being applied to a number of neurologic conditions such as demyelinating and neurodegenerative disease. Swept-source OCT and enhanced-depth imaging OCT are refining the fine-grained analysis of the optic nerve head in the diagnosis of papilledema and optic nerve drusen. OCT-angiography is opening up new avenues to the study of the vasculature of the optic nerve head and its disorders, including ischemic optic neuropathy. Newer technologies in the diagnosis of GCA include vascular ultrasound, magnetic resonance imaging (MRI) of the extracranial vasculature and PET imaging of the large vessels. SUMMARY: OCT and several of its derivations are advancing diagnosis, and in some cases prognostication, in a variety of inflammatory, ischemic and compressive optic neuropathies. These technologies hold potential in the laboratory as well, yielding insights into the mechanisms of a variety of neurological conditions. In addition, further developments in MRI and ultrasonography techniques are shaping the approach to the diagnosis of GCA.
Inflammatory cerebral amyloid angiopathy is a largely reversible inflammatory vasculopathy that develops in an acute or subacute fashion in reaction to amyloid protein deposition in the central nervous system blood vessels. There are two recognized pathologically characterized variants: cerebral amyloid angiopathy-related inflammation (CAAri) and A beta-related angiitis (ABRA). Both variants produce a clinical picture that resembles primary angiitis of the CNS but is distinguished by a characteristic radiologic appearance. Although originally defined as a clinicopathologic diagnosis, it can now often be diagnosed based on clinicoradiologic criteria, though confirmation with brain and meningeal biopsy is still required in some cases. This disorder typically responds to steroids but addition of other immune suppressants may be needed in some cases to control the disease.
BACKGROUND: Myelin oligodendrocyte glycoprotein antibody disease (MOGAD) is an important etiology of neurologic morbidity and specifically, atypical, and relapsing optic neuritis. This review summarizes acute treatment and long-term prevention approaches in MOGAD. EVIDENCE ACQUISITION: PubMed and Google Scholar databases were manually searched and reviewed. RESULTS: We review the evidence base for acute treatment of MOGAD with corticosteroids and adjunct therapies, such as intravenous immunoglobulin (IVIg) and plasma exchange. We discuss the utility of prolonged corticosteroid tapering after the acute attack. We then summarize the commonly used disease-modifying treatments for relapsing MOGAD, including chronic low-dose corticosteroids, classic antirheumatic immune suppressants, biologic agents, and IVIg. CONCLUSIONS: While acute MOGAD attacks are usually treated with high-dose IV corticosteroids, longer oral corticosteroid tapers may prevent rapid relapse. Multiple long-term treatment strategies are being employed in recurrent MOGAD, with IVIg is emerging as probably the most effective therapy.
PURPOSE OF REVIEW: IgG4-related disease (IgG4-RD) is increasingly recognized as a fibroinflammatory disease with a plethora of organ-specific manifestations but a particular predilection for head and neck tissues, including the nervous system. This review discusses general features and organ-specific presentations of IgG4-RD as well as treatment considerations, particularly emphasizing features of neuro-ophthalmic interest. RECENT FINDINGS: IgG4-RD is emerging as a common cause of several fibroinflammatory disorders in the head and neck that were previously considered idiopathic, such as sclerosing orbital pseudotumor, orbital myositis, hypophysitis, and hypertrophic pachymeningitis. New and unusual presentations continue to be described, including a number of vascular manifestations. Substantial progress has been made in elucidating the cell types involved in IgG4-RD, and new pathogenic models are being proposed. Although clinicopathologic correlation remains the cornerstone of diagnosis, ancillary tests such as flow cytometry for circulating plasmablasts and PET-computed tomography have high sensitivity, and certain radiologic features are recognized to be particularly suggestive, such as infraorbital nerve enlargement in IgG4-RD orbitopathy. IgG4-RD often responds to steroids but incomplete responses and relapses are common. Rituximab is emerging as a promising new therapy. SUMMARY: The current review summarizes manifestations of IgG4RD that are of particular relevance to neuro-ophthalmic practice.
A healthy 56-year-old man presented with vision changes and left upper extremity motor and sensory changes. MRI of the brain without contrast was significant for multifocal areas of restricted diffusion in multiple vascular territories. Neuro-Ophthalmic evaluation revealed an inferonasal visual field defect in the left eye, thickened choroid on optical coherence tomography, and bilateral delayed arteriovenous and choroidal filling on fluorescein angiogram. Repeat MRI demonstrated interval enlargement of many of the same foci of abnormal diffusion-weighted imaging signal. Computed tomography of the abdomen and pelvis revealed 3 distinct lobulated retroperitoneal masses that were biopsied and found to be consistent with diffuse large B-cell lymphoma. Brain biopsy specimens showed intravascular lymphocytes, confirming a diagnosis of intravascular lymphoma (IVL). In this diagnostically challenging case, a link was established between the presence of multiple strokes (some of which showed slow evolution over time) and retinochoroidal hypoperfusion, which provided a critical clue to the ultimate diagnosis of IVL.
Discovery and characterization of serologic biomarkers has revolutionized the diagnostic framework of systemic and paraneoplastic autoimmune neuro-ophthalmic diseases. Expanding recognition of the multiple ocular and visual manifestations of these conditions highlights the important role of the referring provider in identifying potential cases. Increasing ease of access to serologic testing also enables these practitioners to initiate the diagnostic work-up in suspected cases. We aimed to provide an update on the current knowledge surrounding and use of relevant autoimmune biomarkers by correlating specific clinical neuro-ophthalmic manifestations with autoantibody biomarkers. The utility of select biomarkers for myasthenia gravis, neuromyelitis optica spectrum disorder, myelin oligodendrocyte glycoprotein-IgG-associated disorder, opsoclonus-myoclonus syndrome, anti-collapsin-response mediator protein-5 optic neuropathy, and glial fibrillary acidic protein-IgG-associated disease are discussed with particular focus on the clinical contexts in which to consider testing.
PURPOSE OF REVIEW: Impaired eye movements are frequently seen in ophthalmic and neurologic clinical practice, especially in individuals with movement disorders. Identification of the abnormal movement can aid initial diagnosis and improve understanding of the underlying disease pathophysiology. The present article reviews the ocular motor manifestations and recent research on them in common movement disorders. RECENT FINDINGS: Ocular motor manifestations and their pathophysiologic correlates are being defined. In particular, study of eye movements can help clarify the changing clinicopathologic spectrum of atypical parkinsonian disorders. The pathophysiology and natural history of blepharospasm are being elucidated. Recent research focuses on high-resolution imaging and other technological advances to improve the sensitivity of the ocular motility exam. Eye movements are being studied as biomarkers for diagnosis and progression in clinical care and trials. SUMMARY: The current review summarizes ocular motor manifestations in common movement disorders, and presents recent research investigating their cause and treatment.
We describe a case of lymphocytic panhypophysitis (LPH) in a 30-year-old woman presenting with throbbing headaches and vision changes during her third trimester. LPH is the rarest subclassification of lymphocytic hypophysitis; it is typically found in males and has not previously been associated with pregnancy. Anterior and posterior pituitary deficits together with headaches should raise a high degree of suspicion regarding the possibility of LPH. The atypical magnetic resonance imaging finding of a heterogeneous pituitary mass additionally raised concern about pituitary apoplexy. Tissue from a transsphenoidal biopsy permitted diagnosis of lymphocytic hypophysitis. There was infiltration of the pituitary gland by small B and T lymphocytes. Resolution of the visual symptoms occurred after the biopsy and treatment with intravenous steroids.
MYF5 is member of the Myc-like basic helix-loop-helix transcription factor family and, in cooperation with other myogenic regulatory factors MYOD and MYF5, is a key regulator of early stages of myogenesis. Here, we report three consanguineous families with biallelic homozygous loss-of-function mutations in MYF5 who define a clinical disorder characterized by congenital ophthalmoplegia with scoliosis and vertebral and rib anomalies. The clinical phenotype overlaps strikingly with that reported in several Myf5 knockout mouse models. Affected members of two families share a haploidentical region that contains a homozygous 10 bp frameshift mutation in exon 1 of MYF5 (c.23_32delAGTTCTCACC [p.Gln8Leufs86]) predicted to undergo nonsense-mediated decay. Affected members of the third family harbor a homozygous missense change in exon 1 of MYF5 (c.283C>T [p.Arg95Cys]). Using in vitro assays, we show that this missense mutation acts as a loss-of-function allele by impairing MYF5 DNA binding and nuclear localization. We performed whole-genome sequencing in one affected individual with the frameshift mutation and did not identify additional rare variants in the haploidentical region that might account for differences in severity among the families. These data support the direct role of MYF5 in rib, spine, and extraocular muscle formation in humans.
BACKGROUND: Photophobia is a potentially debilitating symptom often found in dry eye disease (DE), migraine and traumatic brain injury (TBI). METHODS: We conducted a review of the literature via a PubMed search of English language articles with a focus on how photophobia may relate to a shared pathophysiology across DE, migraine and TBI. RESULTS: DE, migraine and TBI are common conditions in the general population, are often comorbid, and share photophobia as a symptom. Across the three conditions, neural dysregulation of peripheral and central nervous system components is implicated in photophobia in various animal models and in humans. Enhanced activity of the neuropeptide calcitonin gene-related peptide (CGRP) is closely linked to photophobia. Current therapies for photophobia include glasses which shield the eyes from specific wavelengths, botulinum toxin, and inhibition of CGRP and its receptor. Many individuals have persistent photophobia despite the use of these therapies, and thus, development of new therapies is needed. CONCLUSIONS: The presence of photophobia in DE, migraine and TBI suggests shared trigeminothalamic pathophysiologic mechanisms, as explained by central neuroplasticity and hypersensitivity mediated by neuropeptide CGRP. Treatment strategies which target neural pathways (ie, oral neuromodulators, transcutaneous nerve stimulation) should be considered in patients with persistent photophobia, specifically in individuals with DE whose symptoms are not controlled with traditional therapies.
PURPOSE OF REVIEW: Orbital disease represents a diverse spectrum of pathology and can result in a variety of neuro-ophthalmic manifestations. The aim of this review is to provide updates on recent advances in our understanding of orbital disease secondary to thyroid eye disease, myositis, IgG4-related disease, sarcoidosis, granulomatosis with polyangiitis and various tumours. RECENT FINDINGS: With regards to thyroid eye disease, there have been recent advances in the development of steroid-sparing therapies, new modalities for objectively monitoring disease activity and increased understanding of the role of environmental risk factors. There has been interest in characterizing the clinical course and underlying mechanism of optic nerve disease secondary to orbital disorders, which has led to advances in how we monitor for and prevent permanent vision loss. Increased knowledge of orbital tumour subtype histopathology and the development of novel classification systems has had prognostic value and aided medical decision-making. SUMMARY: Orbital disease occurs secondary to a wide variety of diseases and can lead to neuro-ophthalmic manifestations with significant morbidity. Advances in our understanding of different subtypes of orbital disease have improved our ability to treat these potentially debilitating conditions.
History A 24-year-old right-handed woman presented to a neuro-ophthalmology clinic in Massachusetts in the summer with acute binocular diplopia when looking down and to the left, which started about 1 month earlier. Her medical history was notable for Raynaud syndrome, recurrent streptococcal pharyngitis, and an allergy to amoxicillin. Three days prior to developing diplopia, she presented to an outside emergency department due to fever, chills, and back pain. She received ciprofloxacin for presumed urinary tract infection based on urinalysis, which demonstrated few bacteria and was negative for leukocyte esterase, nitrites, and white blood cells. She then presented again to an outside emergency department for diplopia evaluation. Initial MRI and MR angiography of the brain at that time did not demonstrate any relevant findings, and the patient was referred to our department for neuro-ophthalmic evaluation, where she was seen 4 weeks later. Neuro-ophthalmic examination revealed 20/20 visual acuity in both eyes, and a right hypertropia in left gaze, downgaze and right head tilt, with right eye excyclotorsion. There were no ocular signs of myasthenia gravis or thyroid eye disease, nor did the patient report ocular or systemic symptoms. She denied recent travel. High-spatial-resolution MRI of the brain and orbit were performed.