Hypothalamic Myo-Inositol and Glucose concentrations, mood symptoms and fatigue in depression: a 3 Tesla chemical-shift-imaging in vivo proton magnetic resonance spectroscopy study

Background: Many studies have confirmed altered brain Myo-Inositol (mIns) and Glucose (Glc) concentrations in depression. Alterations in the mIns-concentrations may represent a glial dysfunction and are associated mostly with depression symptoms. In comparison, alterations in the Glc-concentrations could represent impaired glucose metabolism. Despite this information, studies that assess these metabolites in the hypothalamus are missing. Therefore, this study aims to investigate mIns- and Glc-concentrations in the hypothalamus of participants with depression concerning mood symptoms and fatigue.Methods: We performed an in vivo proton magnetic resonance spectroscopy – chemical shift imaging of the hypothalamus in 49 participants (25 with depression diagnosis or DE, 24 healthy controls or HC), evaluating mIns- and Glc-concentrations. Concerning information about symptoms, we recollected information on depression symptomatology (BDI-FSTOT) and fatigue (FIS-D). For statistical analysis, we run generalized linear models by using the Poisson regression model with count data.Results: The results showed reduced hypothalamic mIns-concentration for every DE participant with higher FIS-D and higher BDI-FSTOT values (OR = 0.022; p < 0.001; CI95 [0.004 to 0.09]). Besides, the results showed increased hypothalamic Glc-concentration for every participant of the DE group and with higher BDI-FSTOT values (OR = 4.827; p = 0.002; CI95 [1.826 to 13.749]).Conclusions: These results provide initial evidence of a glial dysfunction and impaired glucose metabolism in the hypothalamus associated with mood symptoms and fatigue. Future studies are needed to confirm these pathophysiologic mechanisms.