# Glymphatic System Impairment in Type II Diabetes Mellitus Adults

## TL;DR

This study finds that adults with Type 2 diabetes have impaired brain waste clearance systems, which may contribute to cognitive decline and sleep issues.

## Contribution

This is the first study to evaluate glymphatic system function in Type 2 diabetes using DTI-ALPS imaging.

## Key findings

- T2DM adults showed significantly reduced glymphatic function compared to healthy controls.
- T2DM patients exhibited poorer sleep quality and increased daytime sleepiness.
- Cognitive impairments in T2DM were linked to glymphatic dysfunction and sleep disturbances.

## Abstract

Type 2 diabetes mellitus (T2DM) is associated with multiple systemic complications, including cognitive decline and increased risk of neurodegenerative diseases. The glymphatic system, a brain waste clearance pathway, can be impaired from sleep disturbances common in T2DM, has not been examined. Therefore, the aim was to evaluate glymphatic system in T2DM subjects using diffusion tensor imaging along the perivascular space (DTI-ALPS) index. A total of 78 T2DM adults and 106 healthy controls underwent for brain MRI. Sleep issues were assessed using the Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS), and cognition with the Montreal Cognitive Assessment (MoCA). Group differences in DTI-ALPS, sleep metrics, and MoCA scores were assessed with analysis of covariance (covariates, age, sex, and BMI). T2DM patients exhibited higher PSQI (p = 0.03) and ESS (p = 0.004), reflecting poorer sleep quality and increased daytime sleepiness. MoCA scores were significantly lower in T2DM adults (p = 0.001), with impairments emerged in visuospatial skills, attention, and language. Also, significantly reduced DTI-ALPS values appeared in T2DM over controls (p = 0.003). T2DM adults show impaired glymphatic function along with poor sleep quality and day-time issues. The findings indicate that glymphatic dysfunction potentially-driven by metabolic, vascular, and sleep-related disturbances may exacerbate cognitive deficits in T2DM adults.