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.

Effect of brain-derived neurotrophic factor on c-jun expression in the rd mouse retina

AIM: To determine the location of c-jun protein, dynamic changes in c-jun mRNA and protein expression, and ultrastructure characteristics in the rd mouse retina, following a single dose of brain-derived neurotrophic factor (BDNF) in a short period of time. METHODS: A single intravitreal injection of BDNF at two dosages (25 mu g/L or 50 mu g/L) was given to the right eye of the rd mouse at age 2 and 3 weeks respectively. Two weeks after injection, the location of c-jun protein in the retina was observed by immunofluorescence detection, c-jun mRNA and protein expression in retinas were detected by quantitative real time polymerase chain reaction (RT-PCR) and western immunoblotting analysis, ultrastructure characteristics of retinas were detected by transmission electron microscope (TEM) observation. RESULTS: c-jun protein was expressed in the inner nuclear layer (INL) of retina. BDNF at two dosages (25 mu g/L and 50 mu g/L) increased c-jun mRNA expression at PN-4 weeks respectively (P-1 =0.019, P-2=0.021). 50 mu g/L BDNF increased c-jun protein expression at PN-4 weeks (P =0.000). The retinal ultrastructure was improved. CONCLUSION: The effects of BDNF exerts on the c-jun expression in the retina are dose-dependent and time-dependent, which may mediate photoreceptor rescue indirectly in the pathological process of retinitis pigmentosa (RP)at early stage.

Macular thickness as a predictor of loss of visual sensitivity in ethambutol-induced optic neuropathy

Ethambutol is a common cause of drug-related optic neuropathy.Prediction of the onset of ethambutol-induced optic neuropathy and consequent drug withdrawal may be an effective method to stop visual loss.Previous studies have shown that structural injury to the optic nerve occurred earlier than the damage to visual function.Therefore,we decided to detect structural biomarkers marking visual field loss in early stage ethambutol-induced optic neuropathy.The thickness of peripapillary retinal nerve fiber layer,macular thickness and visual sensitivity loss would be observed in 11 ethambutol-induced optic neuropathy patients（22 eyes） using optical coherence tomography.Twenty-four healthy age-and sex-matched participants（48 eyes） were used as controls.Results demonstrated that the temporal peripapillary retinal nerve fiber layer thickness and average macular thickness were thinner in patients with ethambutol-induced optic neuropathy compared with healthy controls.The average macular thickness was strongly positively correlated with central visual sensitivity loss（r2=0.878,P=0.000）.These findings suggest that optical coherence tomography can be used to efficiently screen patients.Macular thickness loss could be a potential factor for predicting the onset of ethambutol-induced optic neuropathy.

Acute Bilateral Optic Neuritis in Active Ankylosing Spondylitis

Ankylosing spondylitis （AS）, which primarily affects the sacroiliac joints, spine, and enthuses, is a chronic inflammatory rheumatic disorder. Acute anterior uveitis is the most common ophthalmologic involvement, whereas optic neuritis （ON） rarely coexists with AS.r^j ON is an immune-mediated inflammation of the optic nerve, which could be the initiated symptom of multiple sclerosis （MS） or neuromyelitis optica （NMO）. Bilateral simultaneous ON with long enhanced optic nerve lesions in magnetic resonance imaging （MRI） was considered as features of NMO spectrum disorders （NMOSDs）. However, comprehensive review of the current literature showed little evidence of AS as an accompanied autoimmune condition in NMO,121 and the specific biomarker aquaporin-4 antibody （AQP4-Ab） was negative in our patient. In the current report, we present the first case of ON with active AS in a Chinese male patient. The association between the two diseases remains to be evaluated.