Abstract
Diabetes-related brain damage can lead to cognitive decline and increase the risk of depression, but the neuropathological mechanism of this phenomenon remains unclear. Different insular subregions have obvious functional heterogeneity, which is related to many aspects of type 2 diabetes mellitus (T2DM)-related brain damage. However, little is known about changes in functional connectivity (FC) in insular subregions in patients with T2DM. Therefore, we aimed to investigate FC between different insular subregions and clinical/cognitive variables in patients with T2DM. Fifty-seven patients with T2DM and 55 healthy controls (HCs) underwent a neuropsychological assessment and resting-state FC examination. We defined three insular subregions, including the bilateral dorsal anterior insula (dAI), bilateral ventral anterior insula (vAI), and bilateral posterior insula (PI). We examined differences in FC between insular subregions and the whole brain in patients with T2DM compared with HCs. A correlation analysis was performed to examine the relationship between FC and clinical/cognitive variables. Compared with HCs, patients with T2DM showed significantly decreased FC between the dAI and the right inferior frontal gyrus, right superior/middle temporal gyrus, right hippocampus, and right precentral gyrus. FC between the vAI and the right supramarginal gyrus, as well as the PI and the right precentral/postcentral gyrus, was reduced in the T2DM group compared with the control group. In the T2DM group, we showed a significant negative correlation between glycated hemoglobin concentration and FC in the dAI and right hippocampus (r = −0.428, P = 0.001) after Bonferroni correction. We conclude that different insular subregions present distinct FC patterns with functional regions and that abnormal FC in these insular subregions may affect cognitive, emotional, and sensorimotor functions in patients with T2DM.
Highlights
Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease characterized by insulin resistance and long-term hyperglycemia.The number of patients with T2DM worldwide is approximately 445 million, and the incidence is increasing; T2DM is a serious public health problem (Cho et al, 2018)
The results show that compared with the healthy controls (HC) group, functional connectivity (FC) between the dorsal anterior insula (dAI) and multiple cognitive-related brain regions was reduced, while FC between the ventral anterior insula (vAI) and the supramarginal gyrus, as well as between the posterior insula (PI) and the precentral/postcentral gyrus, was decreased in patients with T2DM
This study found that brain regions with different dAI FC in patients with T2DM are mainly located in the default-mode network (DMN) and central executive network (CEN), which may indicate coordination abnormalities among the salience network (SN), CEN, and DMN in patients with T2DM
Summary
Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease characterized by insulin resistance and long-term hyperglycemia.The number of patients with T2DM worldwide is approximately 445 million, and the incidence is increasing; T2DM is a serious public health problem (Cho et al, 2018). Li et al (2018) found that under temperature stimulation, the insula and other sensorimotor regions were activated in patients with T2DM with peripheral neuropathy, which suggests that the insula may play a role in sensorimotor impairment These studies show that insular dysfunction and FC disorder are closely related to the neural mechanism of T2DM-related brain damage, the above results are heterogeneous, and it is difficult to determine the specific role of the insula in T2DM-related brain damage. This may be because almost all previous neuroimaging studies that have investigated insular connectivity in T2DM have treated the insula as a single, homogeneous region, while ignoring functional heterogeneity of insular subregions
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