Perivascular spaces are associated with tau pathophysiology and synaptic dysfunction in early Alzheimer’s continuum
Natàlia Vilor‐Tejedor, Iacopo Ciampa, Grégory Operto, Carles Falcón, Marc Suárez‐Calvet, Marta Crous‐Bou, Mahnaz Shekari, Eider M. Arenaza‐Urquijo, Marta Milà‐Alomà, Oriol Grau‐Rivera, Carolina Minguillón, Gwendlyn Kollmorgen, Henrik Zetterberg, Kaj Blennow, Roderic Guigó, José Luís Molinuevo, Juan Domingo Gispert, for the ALFA study, Annabella Beteta, Anna Brugulat, Raffaele Cacciaglia, Alba Cañas, Carme Deulofeu, Irene Cumplido, Ruth Dominguez, Maria Emilio, Karine Fauria, Sherezade Fuentes, Laura L. Hernandez, Gema Huesa, Jordi Huguet, Paula Marne, Tania Menchón, Albina Polo, Sandra Pradas, Blanca Rodríguez‐Fernández, Aleix Sala‐Vila, Gonzalo Sánchez‐Benavides, Gemma Salvadó, Anna Soteras, Marc Vilanova
Abstract
BACKGROUND: Perivascular spaces (PVS) have an important role in the elimination of metabolic waste from the brain. It has been hypothesized that the enlargement of PVS (ePVS) could be affected by pathophysiological mechanisms involved in Alzheimer's disease (AD), such as abnormal levels of CSF biomarkers. However, the relationship between ePVS and these pathophysiological mechanisms remains unknown. OBJECTIVE: We aimed to investigate the association between ePVS and CSF biomarkers of several pathophysiological mechanisms for AD. We hypothesized that ePVS will be associated to CSF biomarkers early in the AD continuum (i.e., amyloid positive cognitively unimpaired individuals). Besides, we explored associations between ePVS and demographic and cardiovascular risk factors. METHODS: The study included 322 middle-aged cognitively unimpaired participants from the ALFA + study, many within the Alzheimer's continuum. NeuroToolKit and Elecsys® immunoassays were used to measure CSF Aβ42, Aβ40, p-tau and t-tau, NfL, neurogranin, TREM2, YKL40, GFAP, IL6, S100, and α-synuclein. PVS in the basal ganglia (BG) and centrum semiovale (CS) were assessed based on a validated 4-point visual rating scale. Odds ratios were calculated for associations of cardiovascular and AD risk factors with ePVS using logistic and multinomial models adjusted for relevant confounders. Models were stratified by Aβ status (positivity defined as Aβ42/40 < 0.071). RESULTS: The degree of PVS significantly increased with age in both, BG and CS regions independently of cardiovascular risk factors. Higher levels of p-tau, t-tau, and neurogranin were significantly associated with ePVS in the CS of Aβ positive individuals, after accounting for relevant confounders. No associations were detected in the BG neither in Aβ negative participants. CONCLUSIONS: Our results support that ePVS in the CS are specifically associated with tau pathophysiology, neurodegeneration, and synaptic dysfunction in asymptomatic stages of the Alzheimer's continuum.