Background and Objectives Microglia, the resident immune cell of the brain and retina, is widespread activated in the white and gray matter (GM) in multiple sclerosis (MS). The objective of this study is to evaluate the presence and number of hyperreflecting foci (HRF), considered clusters of activated and proliferating retinal microglia, and their association with clinical and radiologic disease parameters in relapsing-remitting MS (RRMS). Methods At baseline, 80 patients with RRMS underwent optical coherence tomography (OCT) and 3T-MRI (including 3-dimensional T1, fluid-attenuated inversion recovery, and double inversion recovery sequences), closed to their disease onset (6.3 ± 5.1 months). These patients were then clinically and radiologically followed up for a mean of 43 months, evaluating the no evidence of disease activity (NEDA) condition, further divided into clinical (cNEDA) and radiologic (rNEDA). Patients with a clinical history or MRI/OCT findings suggestive of optic neuritis (ON) were excluded from the study. Results Compared with healthy controls, the HRF number was significantly higher in the inner nuclear layer (INL) of patients with RRMS (19.55 ± 5.65 vs 13.84 ± 2.57, p < 0.001) and associated with INL volume (β: 1.21, p < 0.001). GM lesion volume significantly correlated with the INL HRF count (p = 0.008). Survival analysis revealed a significant association between INL HRF and both cNEDA (p = 0.017) and rNEDA (p = 0.002). Discussion We found a strong association between retinal microglial proliferation and cortical pathology in RRMS, a finding suggesting a possible underlying common immunopathologic mechanism. Furthermore, microglial activation at baseline was observed to predict subsequent inflammatory events, indicating that HRF might be a candidate prognostic biomarker worthy of further investigation. Classification of Evidence This study provides Class II evidence that in patients with early RRMS but without ON, the number of HRF on OCT of the retinal inner nuclear layer is associated with cNEDA and rNEDA.

Background: Previous studies, dating back to the 1960s disclosed a progressive increase in multiple sclerosis (MS) incidence and prevalence in the Province of Padua. To further analyze whether this trend is the effect of the improved diagnostic procedures or is primarily related to a real increase risk of MS, we analyzed MS incidence and prevalence of the 5-year period 2011–2015. Methods: Patients with a diagnosis of MS or clinically isolated syndrome highly suggestive of MS were included in the study. All available sources of clinical and administrative information were evaluated. Mean annual incidence in the 5-year period 2011–2015 and the prevalence on December 31, 2015 were calculated. Results: The 2011–2015 mean incidence was 6.5/100,000/year, 7.9 for females, 4.1 for males. The overall prevalence was 182/100,000, 241 for females, 116 for males. Compared to the 2000–2009 period, mean age at onset, onset-diagnosis delay and F/M ratio did not significantly change. Since the 1960s, incidence and prevalence of MS linearly increased with no interposed plateau periods. Conclusions: MS incidence and prevalence further and significantly increased in the period 2011–2015. Our 1965–2015 data indicate a real increased risk of MS and stress a role of exogenous factors in MS susceptibility.

Background: To what extent the progressive increase in the incidence of multiple sclerosis (MS) observed in the province of Padova over the period 1970–1999 was an expression of a real increased risk of developing MS remained unclear. Objective: The objective of this paper is to update the epidemiological figures of MS and probe whether the risk of having MS has increased in the province of Padova during the decade 2000–2009. Methods: All patients born in Italy and having a diagnosis of MS or possible MS identified through analysis of all available sources of information were included in the study. The incidence and prevalence rates between 2000 and 2009 were obtained and compared with our previously published data. Results: On 31 December 2009, the overall prevalence was 139.5/100,000, 192.0±9.5 for females and 83.9±6.3 for males. During the decade 2000–2009, the overall incidence rate of MS was 5.5±0.5, 7.4±0.8 for females and 3.5±0.6 for males. The onset-diagnosis delay, the female/male ratio and the mean age at onset did not significantly change compared to the prior period of observation. Conclusion: Our findings support the hypothesis of a real increased risk of developing MS in the province of Padova. Moreover, the actual prevalence of 1.4/1000 makes our region a high-risk geographical area for MS. The role played by exogenous factors in determining susceptibility to MS needs to be thoroughly investigated.