Structural Alterations of Segmented Macular Inner Layers in Aquaporin4-Antibody-Positive Optic Neuritis Patients in a Chinese Population

Abstract

ObjectivesThis study aimed to analyse the structural injury of the peripapillary retinal nerve fibre layer (pRNFL) and segmented macular layers in optic neuritis (ON) in aquaporin4-antibody (AQP4-Ab) seropositivity(AQP4-Ab-positiveON) patients and in AQP4-Ab seronegativity (AQP4-Ab-negative ON) patients in order to evaluate their correlations with the best-corrected visual acuity (BCVA) and the value of the early diagnosis of neuromyelitis optica (NMO).DesignThis is a retrospective, cross-sectional and control observational study.MethodsIn total, 213 ON patients (291 eyes) and 50 healthy controls (HC) (100 eyes) were recruited in this study. According to a serum AQP4-Ab assay, 98 ON patients (132 eyes) were grouped as AQP4-Ab-positive ON and 115 ON patients (159 eyes) were grouped as AQP4-Ab-negative ON cohorts. All subjects underwent scanning with spectralis optical coherence tomography (OCT) and BCVA tests. pRNFL and segmented macular layer measurements were analysed.ResultsThe pRNFL thickness in AQP4-Ab-positive ON eyes showed a more serious loss during 0–2 months (-27.61μm versus -14.47 μm) and ≥6 months (-57.91μm versus -47.19μm) when compared with AQP4-Ab-negative ON eyes. AQP4-Ab-positive ON preferentially damaged the nasal lateral pRNFL. The alterations in the macular ganglion cell layer plus the inner plexiform layer (GCIP) in AQP4-Ab-positive ON eyes were similar to those in AQP4-Ab-negative ON eyes. AQP4-Ab-positive ON eyes had entirely different injury patterns in the inner nuclear layer (INL) compared with AQP4-Ab-negative ON eyes during the first 6 months after the initial ON attack. These differences were as follows: the INL volume of AQP4-Ab-positive ON eyes had a gradual growing trend compared with AQP4-Ab-negative ON eyes, and it increased rapidly during 0–2 months, reached its peak during 2–4 months, and then decreased gradually. The pRNFL and GCIP in AQP4-Ab-positive ON eyes had positive correlations with BCVA. When the pRNFL thickness decreased to 95%CI (50.77μmto 60.85μm) or when the GCIP volume decreased to 95%CI (1.288 mm3to 1.399 mm3), BCVA began to be irreversibly damaged.ConclusionThe structural alterations of pRNFL and GCIP could indicate the resulting visual damage. In addition, the injury pattern of INL could be a potential structural marker to predict the conversion of ON to NMO.

Retinal segmented layers with strong aquaporin-4 expression suffered more injuries in neuromyelitis optica spectrum disorders compared with optic neuritis with aquaporin-4 antibody seronegativity detected by optical coherence tomography

“…The latter ON is likely to progress to MS or isolated ON after frequent recurrences of ON in clinical practice. Previously, studies about structural injuries by OCT in NMO-ON and AQP4-Ab+/ON (NMOSD) versus AQP4-Ab−/ON were scarce 4. However, for NMO-ON versus MS-ON, there have been many studies8–13 in recent years, as well as the present study, that showed that NMO-ON caused more damage in the pRNFL and inner macular segmented layers.…”

“…Therefore, AQP4-Ab+/ON is considered an early or limited type of NMO and has been named an NMO spectrum disorder (NMOSD). Our previous study also demonstrated that AQP4-Ab+/patients with ON had injury patterns distinct from those of AQP4-Ab seronegative ON (AQP4-Ab−/ON) patients in the peripapillary retinal nerve fibre layer (pRNFL) and inner nuclear layer (INL) and measurements of AQP4 -Ab levels were more important in patients with ON who will develop NMO compared with other autoantibodies 4 5. However, the pathogenesis of definite NMO involves more than AQP4-Ab+/ON.…”

“…Most previous studies have focused on the distinct structural injury patterns of NMO with ON (NMO-ON) compared with MS with ON (MS-ON)8–13 and sought structural biomarkers to predict if ON would progress to MS or NMO 4 14. However, these studies often pooled NMO and AQP4-Ab+/ON, which is one type of NMOSD, as a cohort, regardless of the differences between NMO and AQP4-Ab+/ON (NMOSD).…”

Clinical characteristics and prognosis of myelin oligodendrocyte glycoprotein antibody-seropositive paediatric optic neuritis in China

“…The superior and inferior quadrants of pRNFL were preferentially damaged in AQP4-ON eyes compared with the MOG-ON eyes, which is consistent with previous studies. This may be because AQP4 is strongly expressed in the superior and inferior quadrants of the pRNFL with plenty of vessels and facing vitreous bodies, which can cause parallel and more severe injury and induce more pRNFL thinning in AQP4-ON eyes 5. Our study also found damage preferentially occurred in the superior, temporal inferior and temporal superior quadrants of the mGCIPL in AQP4-ON eyes compared with MOG-ON eyes.…”

“…In the Chinese population, NMO is the more common central nervous system inflammatory demyelinating disorder 5. The presence of aquaporin-4 (AQP4) antibody is an important biomarker for neuromyelitis optica spectrum disorders (NMOSDs) 6 7.…”