Neurochemical profile of patients with type 1 diabetes measured by ¹H-MRS at 4 T

The impact of type 1 diabetes mellitus (T1DM) on a comprehensive neurochemical profile of the human brain has not been reported yet. Our previous proton magnetic resonance spectroscopy (1 H-MRS) studies on T1DM were focused exclusively on the assessment of brain glucose levels. In this study, we reexamined our previously acquired data to investigate concentration differences of a broad range of neurochemicals in T1DM subjects relative to nondiabetic controls. We selected MRS data from 13 subjects (4 F/9 M, age=41±11 years, body mass index=26±3 kg/m 2) with well-controlled T1DM (disease duration=22±12 years, A1C=7.5%±2.0%) and 32 nondiabetic controls (14 F/18 M, age=36±10 years, body mass index=27±6 kg/m 2) acquired during a hyperglycemic clamp (target Glc plasma =300±15 mg/dL). The 1 H-MR spectra were collected from two 15.6-mL voxels localized in gray-matter-rich occipital lobe and in white-matter-rich parieto-occipital region using ultra-short echo-time STEAM at 4 T. LCModel analysis allowed reliable quantification of 17 brain metabolites. Lower levels of N-acetylaspartate (by 6%, P=0.007) and glutamate (by 6%, P=0.045) were observed in the gray matter of T1DM patients as compared with controls, which might indicate a partial neuronal loss or dysfunction as a consequence of long-term T1DM. No other differences in metabolites were observed between subjects with T1DM and controls.