Relationship Between Plasma Leptin Level and Brain Structure in Elderly: A Voxel-Based Morphometric Study

Background: Recent accumulating lines of evidence reveal that leptin is associated with synaptic plasticity and neuroprotective activity in the brain. Methods: In this preliminary study with a cross-sectional design, we examined the relationship between plasma leptin level and total or regional gray matter (GM) volume in 34 elderly subjects (mean age 64.5 years) with normal fasting glucose level and without dementia and metabolic syndrome by voxel-based morphometry of magnetic resonance imaging scans. Results: Plasma leptin level showed no significant correlation with total GM volume but showed a significantly positive correlation with GM volumes in the right hippocampus, left parahippocampus, and right cerebellum with adjustments for age, gender, body mass index (BMI), and waist-to-hip ratio (W/H). Also, after adjustments for age, gender, BMI, W/H, and intracranial volume, plasma leptin level significantly positively correlated with GM volumes in the right hippocampus and bilateral cerebella but not with that in the left parahippocampus. Conclusions: The results of this pilot study would be beneficial for our understanding of the neuroprotective effects of leptin on human brain aging.