Structural impairment patterns in peripapillary retinal fiber layer and retinal ganglion cell layer in mitochondrial optic neuropathies

AIM：To evaluate the structural injure patterns in peripapillary retinal fiber layer （pRNFL）, retinal ganglion cell layer （RGCL） and their correlations to visual function in various mitochondrial optic neuropathies （MON） to offer help to their differential diagnosis.METHODS：Totally 32 MON patients （60 eyes） were recruited within 6mo after clinical onsets, including 20 Leber hereditary optic neuropathy （LHON） patients （37eyes）, 12 ethambutol-induced optic neuropathy （EON）patients （23 eyes）, and 41 age-gender matched healthy controls （HC, 82 eyes）. All subjects had pRNFL and RGCL examinations with optic coherence tomography （OCT） and visual function tests.RESULTS：In the early stages of MON, the temporal pRNFL thickness decreased （66.09±22.57μm）, but increased in other quadrants, compared to HC （76.95±14.81μm）. The other quadrants remaining stable for LHON and EON patients besides the second hour sector of pRNFL thickness reduced and the temporal pRNFL decreased （56.78±15.87μm） for EON. Total macular thickness in MON reduced remarkably（279.25±18.90μm; P=0.015）, which mainly occurring in the inner circle （3 mm diameter of circle） and the nasal temporal sectors in the outer circle （5.5 mm diameter of circle）, in contrast to those in HC. RGCL thickness reduced in each sector of the macula （61.90±8.73μm; P≤0.001）. It strongly showed the correlationship of best corrected visual acuity （R=0.50, P=0.0003） and visual field injury （R=0.54,P=0.0002） in MON patients.CONCLUSION：OCT is a potential tool for detecting structural alterations in the optic nerves of various MON. Different types of MON may have different damage patterns.

ROCK inhibition as a novel potential strategy for axonal regeneration in optic neuropathies

Optic neuropathies or optic nerve diseases are a frequent cause of permanent vision loss that can occur after inflammation,ischemia,infection,tumors,trauma and/or an elevated pressure inside the eye（also called intraocular pressure or IOP）.

Retinal nerve fiber and ganglion cell layer thinning in hereditary and acquired mitochondrial optic neuropathies

Dear Editor,With interest we read the article by Teng et al[1]about a study of the retinal nerve and ganglion cell layers by means of optic coherence tomography(OCT)in 32 patients with a mitochondrial optic neuropathy(MON).Included were 20 patients with hereditary MON[Leber’s hereditary optic neuropathy(LHON)],12 patients with acquired MON[ethambutol-induced optic neuropathy(EION)],and 41 healthy controls.Retinal nerve fiber layer(RNFL)thickness was reduced in the nasal,superior,temporal,and inferior quadrants in LHON patients but only in the temporal quadrant in the EION patients.Thickness of the retinal ganglion cell layer(RGCL)was similarly reduced in LHON and EION patients.We have the following comments and concerns.

Cellular reprogramming and inherited peripheral neuropathies: perspectives and challenges

Inherited peripheral neuropathies （or Charcot-Marie-Tooth disease, CMT） are a phenotypically and genetically heterogeneous group of disorders, which are currently untreatable. They are the most common inherited neuromuscular disorder, affecting around 1 in every 2,500 people （over 120,000 people in the US）. Based on clinical neurophysiological and histopathological features, inherited neuropathies can be divided into two major forms： demyelinating （type 1） and axonal （type 2） CMT （Saporta, 2014）.

Demonstration of reversible retinal ganglion cell dysfunction in inflammatory optic neuropathies utilizing pattern electroretinography

Dear Editor,I am Dr.Austin Bach from Larkin Community Hospital in South Miami,Florida,USA.I am writing to you to present three cases of inflammatory optic neuritis that was followed to resolution using pattern electroretinography（PERG）.

Neurorestoration from medicinal plants:an opportunity to treat painful neuropathies

Neuropathic pain originates from damages to the somatosensory nervous system（IASP-International Association for the Study of Pain-taxonomy）.Lesions（traumas,compression,iatrogenic and pharmacological causes）or diseases（infections,diabetes,ischemia,cancer）lead to the establishment of hypersensitivity.

Clinical analysis of symmetry peripheral entrapment neuropathies of upper extremity

Objective To discuss the etiology,course of diseases and prognosis of symmetry peripheral entrapment enuropathies of upper extremity. Methods The etiology, clinical scale and resluts of 14 cases were analyzed betwen 1999 and April 2002. Results In the bilateral tunnel syndrome, the excellent and good rate was 60% at the original side and 80% at the contralateral side occurred later. In the bilateral carpal tunnel syndrome, the excellent and good rate was 67% at the original side and 89% at the contralateral side occurred later. Conclusion The main etiological factor of the bilateral cubital tunnel syndrome was the elbow eversion deformity. The lesions of synovium contributed mainly to the symmetry carpal tunnel syndrome. The symmetry peripheral entrapment neuropathies of upper extremity should be operated on as soon as possible when diagnosis had been made for enhancement of treatment outcome. 5 refs,2 tabs.

Entrapment neuropathies in diabetes mellitus

Neuropathy is a common complication of diabetes mellitus(DM) with a wide clinical spectrum that encompasses generalized to focal and multifocal forms. Entrapment neuropathies(EN), which are focal forms, are so frequent at any stage of the diabetic disease, that they may be considered a neurophysiological hallmarkof peripheral nerve involvement in DM. Indeed, EN may be the earliest neurophysiological abnormalities in DM,particularly in the upper limbs, even in the absence of a generalized polyneuropathy, or it may be superimposed on a generalized diabetic neuropathy. This remarkable frequency of EN in diabetes is underlain by a peculiar pathophysiological background. Due to the metabolic alterations consequent to abnormal glucose metabolism,the peripheral nerves show both functional impairment and structural changes, even in the preclinical stage,making them more prone to entrapment in anatomically constrained channels. This review discusses the most common and relevant EN encountered in diabetic patient in their epidemiological, pathophysiological and diagnostic features.

Peripheral Neuropathies Revealing Gougerot-Sjögren’s Syndrome: Description of 3 Cases

Introduction: Sjögren’s syndrome is an autoimmune epithelitis with various extraglandular signs, among which are neurological, with a variable frequency according to studies. We report three cases of peripheral neuropathy revealing Gougerot-Sjögren’s syndrome, collected in the Neurology Department of the Fann University Hospital in Dakar (Senegal). Observations: The first patient, aged 48 years, presented with a length-dependent sensitivomotor polyneuropathy associated with retrobulbar optic neuritis, with dry eyes and dry mouth noticed by the patient for several years. The second patient, aged 28 years, was admitted to the hospital with chronic generalized paresthesia in the context of xerostomia and xerophthalmia. The results of the clinical examination and the electroeneuromyogram were in favour of pure sensory neuronopathy. The third patient was 32 years old female, with a history of thyroidectomy and acute inflammatory demyelinating polyneuropathy (AIDP), who was seen for acute ascending flaccid tetraplegia with facial diplegia, preceded by diffuse paresthesia. The diagnosis of recurrence of acute demyelinating polyradiculonueropathy was retained in view of the rapidly increasing character of the deficit, the hyperproteinorachy at the lumbar puncture, and the signs of demyelination at the ENMG. The diagnosis of Gougerot-Sjögren’s syndrome in our three patients was established on the basis of the 2016 ACR/EULAR criteria. Indeed, the anti-SSA antibodies (Ro) were positive in our 3 patients with a biopsy of the salivary glands which showed stage 3 in the first patient and stage 4 in the two others. Corticosteroid therapy and immunosuppressive treatment resulted in a favourable clinical evolution on the neurological and general levels. Conclusion: Gougerot-Sjögren’s syndrome is an autoimmune exocrinopathy that may present with peripheral neuropathy, which may precede the diagnosis of Sjögren’s syndrome, be concomitant or occur during the course of the disease.

Cranial neuropathies in sarcoidosis

Sarcoidosis is a multisystem, chronic inflammatory disease that is characterized by the development of non-caseating granulomas in multiple body tissues and organ systems. Neurological complications of systemic sarcoidosis include peripheral and cranial neuropathies, myopathies, seizures, gait dysfunction, and cognitive decline. Because sarcoidosis has a predilection to involve the basilar meninges, cranial neuropathy is the most prevalent neurological deficit seen when the nervous system is involved. Sarcoidosis cranial neuropathy may occur at different stages of the disease and even as the initial clinical manifestation of central nervous system involvement. Attributing a cranial neuropathy to sarcoidosis can be challenging, particularly in the setting of normal imaging studies. In this review, cranial neuropathies in sarcoidosis are discussed in detail.

Ischemic optic neuropathies-update

This submission will briefly review the anatomy and physiology of the optic nerve,and highlight various ischemic optic neuropathies including anterior ischemic optic neuropathies(non-arteritis and arteritic),diabetic papillopathy,posterior ischemic optic neuropathies,and ischemic optic neuropathies in the setting of hemodynamic compromise.

Application of optical coherence tomography in hereditary,toxic and metabolic optic neuropathies

Hereditary,metabolic and toxic optic neuropathies cause bilateral,central vision loss and therefore can result in severe impairment in visual function.Accurate,early diagnosis is critical,as nutritional and toxic optic neuropathies may be reversible if identified early,and diagnosis of hereditary optic neuropathies can prevent unnecessary invasive workup,provide prognostic information,and allow for effective genetic counseling.Optical coherence tomography(OCT)is a valuable tool that aids in the diagnosis and prognostication of optic neuropathies as it allows for quantification of changes in the retinal ganglion cells(RGCs)and retinal nerve fiber layer(RNFL)over time.We review the characteristic clinical presentations of hereditary,metabolic and toxic optic neuropathies,with an emphasis on OCT findings.

Frequency, Risk Factors and Clinical Forms of Neuropathies in Diabetics in Hospitals in Burkina Faso

Introduction: Diabetic neuropathy is one of the most common chronic complications of diabetes. Most of the studies on the subject in the sub region, particularly in Burkina Faso, dealt it with the study of the complications of diabetes, or one of its components. Our study was designed to study in particular in all its aspects, by searching for its peculiarities in our context, for improvement of its support. Methodology: This is a cross-sectional descriptive study carried out in 150 diabetic patients aged at least 15 years followed in the Department of Internal Medicine at Yalgado Ouedraogo University Teaching Hospital. All patients included had agreed to participate in our survey after informed consent. We collected the data during the period from 2015 November to 2016 June. Each patient was evaluated by the DN4 questionnaire and clinically by a neurological examination. We determinated the frequency, the sociodemographic, clinical and therapeutic characteristics of diabetes neuropathy and its related factors. Results: The frequency of diabetic neuropathy was 80.7%. Peripheral neuropathies were seen in 81.8% of cases and autonomic neuropathies in 72.7% of cases. Autonomic neuropathy was dominated by the DAN (59.1%), and erectile dysfunction (44%). There was a high comorbidity with physical inactivity (66.9%), obesity (49.4%) and hypertension (38.8%). There were poorly controlled patients in 38.8%. A link was found between T2DM and neuropathy (p = 0.014). Painful diabetes was related to the quality of glycemic control (p = 0.007), and hypertension (p = 0.021). A link was also found between tobacco consumption (p < 0.001), male (p < 0.001), and urogenital autonomic neuropathy. Conclusion: Diabetic neuropathies are very common in our context and could be a haunting to the practitioner with the progression of diabetes and its corollary of degenerative complications. There was a significant association between Type 2 Diabetes mellitus and the presence of peripheral diabetic neuropathy.

Cell metabolism pathways involved in the pathophysiological changes of diabetic peripheral neuropathy

Diabetic peripheral neuropathy is a common complication of diabetes mellitus.Elucidating the pathophysiological metabolic mechanism impels the generation of ideal therapies.However,existing limited treatments for diabetic peripheral neuropathy expose the urgent need for cell metabolism research.Given the lack of comprehensive understanding of energy metabolism changes and related signaling pathways in diabetic peripheral neuropathy,it is essential to explore energy changes and metabolic changes in diabetic peripheral neuropathy to develop suitable treatment methods.This review summarizes the pathophysiological mechanism of diabetic peripheral neuropathy from the perspective of cellular metabolism and the specific interventions for different metabolic pathways to develop effective treatment methods.Various metabolic mechanisms(e.g.,polyol,hexosamine,protein kinase C pathway)are associated with diabetic peripheral neuropathy,and researchers are looking for more effective treatments through these pathways.

Enteric neuropathy in diabetes:Implications for gastrointestinal function

Diabetes,commonly known for its metabolic effects,also critically affects the enteric nervous system(ENS),which is essential in regulating gastrointestinal(GI)motility,secretion,and absorption.The development of diabetes-induced enteric neuropathy can lead to various GI dysfunctions,such as gastroparesis and irregular bowel habits,primarily due to disruptions in the function of neuronal and glial cells within the ENS,as well as oxidative stress and inflammation.This editorial explores the pathophysiological mechanisms underlying the development of enteric neuropathy in diabetic patients.Additionally,it discusses the latest advances in diagnostic approaches,emphasizing the need for early detection and intervention to mitigate GI complications in diabetic individuals.The editorial also reviews current and emerging therapeutic strategies,focusing on pharmacological treatments,dietary management,and potential neuromodulatory interventions.Ultimately,this editorial highlights the necessity of a multidisciplinary approach in managing enteric neuropathy in diabetes,aiming to enhance patient quality of life and address a frequently overlooked complication of this widespread disease.

A genetic variant study of bortezomib-induced peripheral neuropathy in Chinese multiple myeloma patients

Background:Bortezomib results in peripheral neuropathy(PN)in approximately 50%of patients,during multiple myeloma(MM)treatment,a complication known as Bortezomib-induced peripheral neuropathy(BIPN).The drug response varies among individuals.Genetic factor may play an important role in BIPN.Methods:A nextgeneration sequencing(NGS)panel containing 1659 targets from 233 genes was used to identify risk variants for developing BIPN in 204 MM patients who received bortezomib therapy.mRNA expression of MTHFR and ALDH1A1 in 62 peripheral blood samples was detected by real-time quantitative PCR(RT-qPCR).Serum homocysteine(Hcy)levels were detected in 40 samples by chemiluminescent microparticle immunoassay(CMIA).Results:Compared with the non-BIPN group(n=89),a total of 8 significantly associated single nucleotide polymorphisms(SNPs)were identified in the BIPN group(n=115):MTHFR(rs1801131,rs1801133,rs17421511),EPHX1(rs1051740),MME(rs2016848),ALDH1A1(rs6151031),HTR7(rs1935349)and CYP2A6(rs8192720).The mRNA expression level of MTHFR in newly diagnosed patients with peripheral neuritis after treatment(NP group)was lower than that of newly diagnosed patients without peripheral neuritis after treatment(NnP group)(1.70±0.77 vs.2.81±0.97,p=0.009).Serum Hcy levels were significantly higher in BIPN group than in non-BIPN group(11.66±1.79μmol/L vs.8.52±3.29μmol/L,p=0.016)and healthy controls(11.66±1.79μmol/L vs.8.55±2.13μmol/L,p≤0.001).Conclusion:CYP2A6,EPHX1,MTHFR,ALDH1A1,HTR7,MME and BIPN are linked in Chinese MM patients.BIPN is more likely to occur in patients with lower MTHFR mRNA expression,which might result in higher serum Hcy levels.

Targeting muscle to treat Charcot-Marie-Tooth disease

Charcot-Marie-Tooth disease(CMT)is a hereditary peripheral neuropathy causing muscle weakness/wasting and sensory dysfunction predominantly in limb extremities.CMT patients display gait abnormalities,foot deformities,loss of sensation and decreased/absent deep tendon reflexes,with motor symptoms usually being more prominent than sensory.

Clinical associations of corneal neuromas with ocular surface diseases

Corneal neuromas,also termed microneuromas,refer to microscopic,irregula rly-shaped enlargements of terminal subbasal nerve endings at sites of nerve damage or injury.The formation of corneal neuromas results from damage to corneal nerves,such as following corneal pathology or corneal or intraocular surge ries.Initially,denervated areas of sensory nerve fibers become invaded by sprouts of intact sensory nerve fibers,and later injured axons regenerate and new sprouts called neuromas develop.In recent years,analysis of corneal nerve abnormalities including corneal neuromas which can be identified using in vivo confocal microscopy,a non-invasive imaging technique with microscopic resolution,has been used to evaluate corneal neuropathy and ocular surface dysfunction.Corneal neuromas have been shown to be associated with clinical symptoms of discomfort and dryness of eyes,and are a promising surrogate biomarker for ocular surface diseases,such as neuropathic corneal pain,dry eye disease,diabetic corneal neuropathy,neurotrophic keratopathy,Sjogren's syndrome,bullous keratopathy,post-refra ctive surgery,and others.In this review,we have summarized the current literature on the association between these ocular surface diseases and the presentation of corneal microneuromas,as well as elaborated on their pathogenesis,visualization via in vivo confocal microscopy,and utility in monitoring treatment efficacy.As current quantitative analysis on neuromas mainly relies on manual annotation and quantification,which is user-dependent and labor-intensive,future direction includes the development of artificial intelligence software to identify and quantify these potential imaging biomarkers in a more automated and sensitive manner,allowing it to be applied in clinical settings more efficiently.Combining imaging and molecular biomarkers may also help elucidate the associations between corneal neuromas and ocular surface diseases.

The concept of gene therapy for glaucoma:the dream that has not come true yet

Gene therapies,despite of being a relatively new therapeutic approach,have a potential to become an important alternative to current treatment strategies in glaucoma.Since glaucoma is not considered a single gene disease,the identified goals of gene therapy would be rather to provide neuroprotection of retinal ganglion cells,especially,in intraocular-pressure-independent manner.The most commonly reported type of vector for gene delivery in glaucoma studies is adeno-associated virus serotype 2 that has a high tro pism to retinal ganglion cells,res ulting in long-term expression and low immunogenic profile.The gene thera py studies recruit inducible and genetic animal models of optic neuropathy,like DBA/2J mice model of high-tension glaucoma and the optic nerve crush-model.Reported gene therapy-based neuroprotection of retinal ganglion cells is targeting specific genes translating to growth factors(i.e.,brain derived neurotrophic factor,and its receptor TrkB),regulation of apoptosis and neurodegeneration(i.e.,Bcl-xl,Xiap,FAS system,nicotinamide mononucleotide adenylyl transferase 2,Digit3 and Sarm1),immunomodulation(i.e.,Crry,C3 complement),modulation of neuroinflammation(i.e.,e rythropoietin),reduction of excitotoxicity(i.e.,Com KIlα)and transcription regulation(i.e.,Max,Nrf2).On the other hand,some of gene therapy studies focus on lowering intra ocular pressure,by impacting genes involved in both,decreasing aqueous humor production(i.e.,aquaporin 1),and increasing outflow facility(i.e.,COX2,prostaglandin F2a receptor,RhoA/RhoA kinase signaling pathway,MMP1,Myocilin).The goal of this review is to summarize the current stateof-art and the direction of development of gene therapy strategies for glaucomatous neuropathy.

Cell replacement with stem cell-derived retinal ganglion cells from different protocols

Glaucoma,characterized by a degenerative loss of retinal ganglion cells,is the second leading cause of blindness worldwide.There is currently no cure for vision loss in glaucoma because retinal ganglion cells do not regenerate and are not replaced after injury.Human stem cell-derived retinal ganglion cell transplant is a potential therapeutic strategy for retinal ganglion cell degenerative diseases.In this review,we first discuss a 2D protocol for retinal ganglion cell differentiation from human stem cell culture,including a rapid protocol that can generate retinal ganglion cells in less than two weeks and focus on their transplantation outcomes.Next,we discuss using 3D retinal organoids for retinal ganglion cell transplantation,comparing cell suspensions and clusters.This review provides insight into current knowledge on human stem cell-derived retinal ganglion cell differentiation and transplantation,with an impact on the field of regenerative medicine and especially retinal ganglion cell degenerative diseases such as glaucoma and other optic neuropathies.