The Glymphatic System and Obesity: A Diffusion Tensor Imaging ALPS Study.

Area of Science:

• Neuroscience
• Radiology
• Public Health

Background:

• Obesity is a known risk factor for neurodegenerative diseases.
• Impaired glymphatic system function may underlie the link between obesity and brain dysfunction.
• Glymphatic function in neurologically healthy obese individuals is not well understood.

Purpose of the Study:

• To investigate glymphatic system function in neurologically healthy adults with varying obesity statuses.
• To determine if the diffusion tensor image analysis along the perivascular space (DTI-ALPS) index differs between obese and non-obese individuals.

Main Methods:

• Retrospective analysis of brain diffusion tensor imaging (DTI) data from 62 neurologically healthy participants.
• Participants stratified into underweight, normal weight, overweight, and obese groups based on WHO Asia-Pacific BMI criteria.
• Group differences in DTI-ALPS index examined using Mann-Whitney U tests and ANCOVA, adjusting for age.

Main Results:

• Obese participants exhibited significantly lower DTI-ALPS index values compared to normal weight and overweight groups (p < 0.05).
• Reduced DTI-ALPS index in obesity persisted after adjusting for age.
• Obesity was associated with a significantly reduced DTI-ALPS index compared to the BMI < 25 kg/m² group (p = 0.015).

Conclusions:

• This study provides the first evidence linking obesity to reduced glymphatic system function in neurologically healthy adults.
• Lower DTI-ALPS index in obese individuals suggests impaired brain waste clearance.
• Maintaining a healthy body weight is vital for preserving glymphatic function and potentially mitigating early neurodegenerative changes.