Alterations of gut microbiota in Down syndrome and their association with Alzheimer's disease.

INTRODUCTION

Adults with Down syndrome (DS) have a higher risk of Alzheimer's disease (AD). As gut microbiota (GM) alterations have been reported in AD, we investigated their association with cognitive decline and plasma AD biomarkers in DS.

METHODS

Fecal and plasma samples were collected from 58 adults with DS (21-75 years) and 30 euploid controls (CTRL; 25-83 years). GM was profiled using 16S rRNA sequencing, filtering low prevalent taxa. Major neurocognitive disorder (NcD) was diagnosed with Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria. Plasma levels of phosphorylated tau 181 (p-tau181), neurofilament light chain (NfL), and glial fibrillary acidic protein (GFAP) were measured using Simoa.

RESULTS

DS showed no changes in overall microbial diversity compared to CTRL, but genera including UBA1819 and Intestinibacter were altered. Specific genera showed changes in DS with NcD, like Alistipes (increased) and Roseburia (decreased), with the latter negatively associated with plasma AD biomarkers.

DISCUSSION: Adults with DS display AD-associated changes in GM partially resembling those reported previously in euploid AD patients.