Irregular structural networks of gray matter in patients with type 2 diabetes mellitus.

Type 2 diabetes mellitus (T2DM) induces dementia and cognitive decrements indicating the impairment of the central nervous system. While there is evidence showing abnormalities in white-matter structural networks in T2DM, the topological features of gray matter are still unknown. The study enrolled 30 right-handed T2DM patients and 20 healthy control subjects with matched age, gender, handedness, and education. Graph theoretical analysis of magnetic resonance imaging on gray matter volume was conducted to explore large-scale structural networks of brain. Although retaining small-worldness characteristics, the structural networks of grey matter in the T2DM group exhibited an increased clustering coefficient, prolonged characteristic path, decreased global efficiency, and more vulnerability to random failures or targeted attacks compared with controls. Additionally, the degree of structural networks in both T2DM and control groups was distributed exponentially in truncated power law. Our findings suggest that T2DM disturbed the overall topological features of gray matter networks, which provides a novel insight into the neurobiological mechanisms accounting for the cognitive impairment of T2DM patients.