HIPPOCAMPAL SUBFIELDS VOLUME REDUCTION IN PATIENTS WITH SYSTEMIC SCLEROSIS: A LONGITUDINAL MAGNETIC RESONANCE IMAGING (MRI) VOLUMETRIC STUDY

Background:Systemic sclerosis (SSc) is a multisystem disease characterized by functional and structural abnormalities of small blood vessels, fibrosis of the skin and internal organs. In addition, volume reduction and shape abnormality of the hippocampus have been demonstrated in rheumatic and neurodegenerative diseases. However, the neuroanatomy of the hippocampus is complex and is not a uniform structure, consisting of subfields with distinct morphology: cornu ammonis (CA) subfields CA1–4, dentate gyrus (DG), fimbria, and adjacent subiculum and presubiculum [1].Objectives:To investigate the hippocampal subfields volumes reduction in SSc patients using MRI.Methods:In this study we included 37 SSc patients (33 women, mean age of 53.46, SD ± 12.29; range 30 - 78) and 37 healthy controls (HC) (31 women, mean age of 48.41, SD±12.20; range 29 - 80). Cognitive evaluation was performed using the Montreal Cognitive Assessment (MoCA), mood disorders were determined through Beck’s Depression (BDI) and Beck’s Anxiety Inventories (BAI). SSc patients were further assessed for clinical and laboratory SSc manifestations, disease activity (Valentini Activity Index), severity activity (Medsger Severity Index). MRI protocol consisted of: Sagittal T1-weighted images performed with a Philips 3.0T MRI scanner. MRI brain structure volumetric was done through volBrain [2]. After 48 months MRI acquisition were repeated in 26 SSc patients and 12 healthy volunteers. Statistics was performed according nature of the variable.Results:We observed a significant reduction in hippocampal subfields volumes in SSc patients when compared to controls: Total hippocampi (SSc: mean volume = 4.78 cm3; SD = 0.38; HC: mean volume = 5.01 cm3; SD = 0.38; p = 0.033). Reduction in volume of the total hippocampi was associated with Raynaud’s phenomenon (p = 0.006). A longitudinal study showed a reduction in volume of the hippocampus subfields volumes when compared to patient’s baseline: Total hippocampi (mean initial volume = 4.78 cm3; mean follow-up volume = 4.50 cm3, p = 0.027); Total CA1 (mean initial volume = 1.59 cm3; mean follow-up volume = 1.58 cm3, p < 0.0001); Reduction in volume of the total hippocampi was associated with presence of current use of prednisone (p = 0.008). Reduction in left CA1 left associated with current use of prednisone (p = 0.014). Reduction in total subiculum was associated with presence of calcinosis (p = 0.023). No significant changes were observed in hippocampal subfields volumes in controls over the follow-up period.Conclusion:This study provides evidence of hippocampus subfields volumes reductions in SSc patients when compared to controls and was associated with Raynaud’s phenomenon, current use of losartan and correlated with BAI scores. Also, a longitudinal study showed a reduction in volume of the hippocampus subfields volumes when compared to patient’s baseline associated with calcinosis and current use of prednisone.References:[1]Eichenbaum, Howard. “A cortical–hippocampal system for declarative memory.” Nature Reviews Neuroscience 1.1 (2000): 41-50.[2]Manjon JV, Coupe P (2016) volBrain: an online MRI brain volumetry system. Front Neuroinform 10:30.Disclosure of Interests:None declared.