Relationship between retinal inner nuclear layer, age, and disease activity in progressive MS
Objective
To investigate whether inner nuclear layer (INL) thickness as assessed with optical coherence tomography differs between patients with progressive MS (P-MS) according to age and disease activity.
Methods
In this retrospective longitudinal analysis, differences in terms of peripapillary retinal nerve fiber layer (pRNFL), ganglion cell layer + inner plexiform layer (GCIPL), INL and T1/T2 lesion volumes (T1LV/T2LV) were assessed between 84 patients with P-MS and 36 sex- and age-matched healthy controls (HCs) and between patients stratified according to age (cut-off: 51 years) and evidence of clinical/MRI activity in the previous 12 months
Results
pRNFL and GCIPL thickness were significantly lower in patients with P-MS than in HCs (p = 0.003 and p < 0.0001, respectively). INL was significantly thicker in patients aged < 51 years compared to the older ones and HCs (38.2 vs 36.5 and 36.7 μm; p = 0.038 and p = 0.04, respectively) and in those who presented MRI activity (new T2/gadolinium-enhancing lesions) in the previous 12 months compared to the ones who did not and HCs (39.5 vs 36.4 and 36.7 μm; p = 0.003 and p = 0.008, respectively). Recent MRI activity was significantly predicted by greater INL thickness (Nagelkerke R 0.36, p = 0.001).
Conclusions
INL thickness was higher in younger patients with P-MS with recent MRI activity, a criterion used in previous studies to identify a specific subset of patients with P-MS who best responded to disease-modifying treatment. If this finding is confirmed, we suggest that INL thickness might be a useful tool in stratification of patients with P-MS for current and experimental treatment choice.
Abstract
Objective
To investigate whether inner nuclear layer (INL) thickness as assessed with optical coherence tomography differs between patients with progressive MS (P-MS) according to age and disease activity.
Methods
In this retrospective longitudinal analysis, differences in terms of peripapillary retinal nerve fiber layer (pRNFL), ganglion cell layer + inner plexiform layer (GCIPL), INL and T1/T2 lesion volumes (T1LV/T2LV) were assessed between 84 patients with P-MS and 36 sex- and age-matched healthy controls (HCs) and between patients stratified according to age (cut-off: 51 years) and evidence of clinical/MRI activity in the previous 12 months
Results
pRNFL and GCIPL thickness were significantly lower in patients with P-MS than in HCs (p = 0.003 and p < 0.0001, respectively). INL was significantly thicker in patients aged < 51 years compared to the older ones and HCs (38.2 vs 36.5 and 36.7 μm; p = 0.038 and p = 0.04, respectively) and in those who presented MRI activity (new T2/gadolinium-enhancing lesions) in the previous 12 months compared to the ones who did not and HCs (39.5 vs 36.4 and 36.7 μm; p = 0.003 and p = 0.008, respectively). Recent MRI activity was significantly predicted by greater INL thickness (Nagelkerke R 0.36, p = 0.001).
Conclusions
INL thickness was higher in younger patients with P-MS with recent MRI activity, a criterion used in previous studies to identify a specific subset of patients with P-MS who best responded to disease-modifying treatment. If this finding is confirmed, we suggest that INL thickness might be a useful tool in stratification of patients with P-MS for current and experimental treatment choice.
Optical coherence tomography (OCT) provides measures of the peripapillary retinal nerve fiber layer (pRNFL) and retinal layer volumes. The progressive thinning of pRNFL and ganglion cell layer + inner plexiform layer (GCIPL) is considered biomarkers of neurodegeneration in MS.1 Conversely, the thickness of inner nuclear layer (INL) has been recently proposed as a measure of inflammatory activity in patients with relapsing-remitting MS (RR-MS).2,3 However, INL has not been extensively studied in patients with progressive MS (P-MS).
Phase III trials have shown that disease-modifying treatments (DMTs) are more efficacious in subgroups of progressive patients aged <51 years and with presence of gadolinium-enhancing lesions on MRI.4 Therefore, we sought to investigate whether INL thickness can reflect inflammation-related differences in patients with P-MS with different range of age and disease activity. A simple and cost-efficient retinal measure could help in identifying patients with P-MS who may benefit from DMTs.
The aims of our study were to (1) characterize INL in patients with P-MS and (2) investigate whether INL thickness differs between patients with P-MS stratified according to age and evidence of disease activity.
Glossary
DMT | disease-modifying treatment |
EDSS | Expanded Disability Status Scale |
GCIPL | ganglion cell layer + inner plexiform layer |
HC | healthy control |
INL | inner nuclear layer |
LV | lesion volume |
MME | microcystic macular edema |
OCT | optical coherence tomography |
ON | optic neuritis |
P-MS | progressive MS |
pRNFL | peripapillary retinal nerve fiber layer |
RR | relapsing-remitting |
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