Aberrant Brain Functional Connectivityin Type 2 Diabetes Mellitus Withoutcognitive Impairment Andcerebrovascular Complications

Aims: To investigate the alterations of brain functional connectivity in type 2diabetes mellitus(T2DM)using resting state f MRI(rs-f MRI),and to determine its correlation with clinical indicators,with a focus on those without clinical evidence of cognitive and cerebrovascular complications.Methods: A total of 27 T2 DM patients and 26 healthy controls(HC)were prospectively examined.Cognitive impairment was excluded by MMSE and Mo CA scales,and cerebrovascular complications were excluded by fundus photograph,microalbuminuria and other indicators.The correlation maps,with the posterior cingulate cortex(PCC)as the seed based on rs-f MRI,were compared between T2 DM and HC.Spearman correlation analysis was performed to determine the relationships between the functional connectivity of PCC and clinical indicators.Results: 1)No significant differences were identified in terms of age,sex,BMI,education level,arterial blood pressure,blood lipids,MMSE and Mo CA scores,while glycated hemoglobin(Hb A1c),Fasting blood glucose(FBG)level in patients with T2 DM were significantly higher than those in the controls;2)Compared with HC,we observed significantly decreased functional connectivity of the PCC within some selected regions,including the bilateral cerebellum posterior lobe;superior frontal gyrus,medial;right superior frontal gyrus,dorsolateral and right thalamus.Increased functional connectivity of the PCC was detected in the right rolandic operculum,right superior temporal gyrus,left cuneus and bilateral calcarine fissure and surrounding cortex;3)A significant correlation was found between its and FBG,Hb A1 c,diabetics duration in type 2 diabetic patients.Conclusions: This study found the aberrant functional connectivity with PCC in T2 DM patients without cognitive impairment and cerebrovascular complications not only was in the cognitive brain regions within the DMN region,but also in the non-DMN regions—the motor and visual brain regions,which maybe helpful for understanding of the mechanisms of brain damage in T2DM-related cognitive,motor,and visual impairment.