Affiliation:
1. Novosibirsk Regional Clinical Hospital;
Novosibirsk State Medical University
2. Novosibirsk State Medical University;
Regional center for multiple sclerosis and other autoimmune diseases of the nervous system, “Novosibirsk Regional Clinical Hospital”
3. Novosibirsk State Medical University
Abstract
Purpose: to identify the intraretinal hyperreflective foci (HRF), their specific characteristics, localization features and correlations with the duration of the disease, type of course and previous episodes of optic neuritis (ON) in multiple sclerosis (MS) patients using a high-resolution OCT scanning protocol. Materials and methods. The study included 160 patients (318 eyes) divided into 8 groups, i.e. Group 1: 44 eyes (13.84 %) — MS onset without a history of ON; Group 2: 30 eyes (9.43 %) — debut of MS with ON; Group 3: 56 eyes (17.61 %) — relapsing-remitting MS (RRMS) lasting ≤ 10 years without ON; Group 4: 38 eyes (11.95 %) — RRMS lasting ≤ 10 years with ON; Group 5: 49 eyes (15.41 %) — RRMS lasting ˃ 10 years without ON; Group 6: 37 eyes (11.63 %) — RRMS lasting ˃ 10 years with ON; Group 7: 34 eyes (10.69 %) — secondary progressive MS (SPMS) without ON; Group 8: 30 eyes (9.43 %) — SPMS with ON. Results. HRF were identified in all groups, at the levels of both the outer nuclear layer (ONL) and the inner nuclear layer (INL). Their number increased depending on the duration, type of course, and the presence of ON history. The thickness of the inner layers of the retina corresponded to the average normative indicators in the group with the onset of MS without ON. In the SPMS group after ON, a decrease in the total thickness of ganglions retinal cells layer (GCL) and the inner plexiform layer (IPL) was noted, showing minimal values of both avGCL + IPL (65.83 ± 8.27 μm) and avRNFL (76.37 ± 6.94 μm). High inverse correlations were revealed between avGCL + IPL and the amount of GRF at the levels of ONL and INL (-0.82 and -0.85, respectively, p = 0.01). Conclusions. The presence and quantity of HRF can be considered as a prognostic non-invasive biomarker associated with the duration of MS and the history of ON, allowing one to visualize the penetration of microglia activated by immune cells into the unmyelinated part of the central nervous system, helpful in elucidating their role in the pathogenesis and progression of the disease.