Structural alterations in deep brain structures in type 1 diabetes

Even though well known in type 2 diabetes, the existence of brain changes in type 1 diabetes (T1D) and both their neuroanatomical and clinical features are less well characterized. To fill the void in the current understanding of this disease, we sought to determine the possible neural correlate in long-duration T1D at several levels including macrostructural, microstructural cerebral damage and blood flow alterations. In this cross-sectional study, we compared a cohort of 61 patients with T1D with an average disease duration of 21 years with 54 well-matched non-diabetic controls in a multimodal magnetic resonance imaging (MRI) protocol providing macrostructural metrics (cortical thickness and structural volumes), microstructural measures (T1w/T2w ratio as a marker myelin content, inflammation and oedema), and cerebral blood flow. T1D patients had higher T1w/T2w ratios in the right parahippocampal gyrus, the executive part of both putamina, both thalami and in the cerebellum. These alterations were reflected in lower putaminal and thalamic volume bilaterally. No cerebral blood flow differences between groups were found in any of these structures, suggesting non-vascular aetiologies of these changes. Our findings implicate a marked non-vascular disruption in T1D of several essential neural nodes engaged in both cognitive and motor processing.