Measures of Brain Metabolism and Diffusion in Neonates of Mothers with Diabetes

Abstract

Background and purpose: Maternal diabetes may affect neonates' long-term neurodevelopment and cognitive behavior. Brain biochemistry and white matter fiber tracts may reveal early changes of brain abnormality. The purpose of this study was to compare brain metabolites and fiber structures in infants of mothers with diabetes with those of mothers without diabetes during the early stage of neonatal neurodevelopment.

Materials and methods: Pregnant women with diabetes mellitus (DM) and healthy controls were recruited prospectively. Baseline characteristics including maternal and gestational age, weight, height, body mass index (BMI), and types of diabetes were extracted from the mothers and neonates in the clinical record. Infants of mothers with diabetes and healthy controls underwent scans by using a 3T MRI scanner. T2-weighted anatomic images were acquired for voxel positioning. ¹H-MR spectroscopy from the right frontal lobe and whole-brain DTI data were acquired from the participants. Independent sample t-tests were used to compare anthropometric data and a general linear model was used to compare brain metabolites and diffusion measures in the neonates.

Results: MRI data were successfully obtained from 77 neonates (41 healthy controls and 36 infants of mothers with diabetes). Gestational diabetes was the most common diagnosis (53%), followed by type 2 (33%) and type 1 pregestational DM (14%). Weight (P = .02) and BMI (P < .01) were significantly higher in mothers with diabetes with earlier birth gestational age. Myo-inositol (mI) measurements were significantly higher (P = .02) in infants of mothers with diabetes versus controls but this was not observed in the excitatory neurotransmitter of γ-aminobutyric acid (GABA) and other high-concentration metabolites. Mean diffusivity values were significantly higher in the anterior part (P = .03) and posterior gray matter (P < .05) of the cingulate gyrus for infants of mothers with diabetes compared with controls. Axial diffusivity values were significantly higher (P = .03) in the anterior part right gray matter of the cingulate gyrus for infants of mothers with diabetes compared with controls.

Conclusions: The increase of myo-inositol in infants of mothers with diabetes may reflect a compensatory mechanism related to altered blood glucose to preserve and promote β-cell growth to enhance the production of insulin. The increase in mean diffusivity is consistent with decreased water diffusion, which potentially reflects abnormal changes in myelination and axonal loss.