A Magnetic Resonance Spectroscopy Study on Polarity Subphenotypes in Bipolar Disorder

• Published in: Diagnostics (Basel) Vol. 14; no. 11; p. 1170
• Main Authors: Argyropoulos, Georgios D, Christidi, Foteini, Karavasilis, Efstratios, Bede, Peter, Velonakis, Georgios, Antoniou, Anastasia, Seimenis, Ioannis, Kelekis, Nikolaos, Smyrnis, Nikolaos, Papakonstantinou, Olympia, Efstathopoulos, Efstathios, Ferentinos, Panagiotis
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 31-05-2024; MDPI
• Subjects: Bipolar disorder; Brain; cingulate cortex; Comparative analysis; Disease; emotion regulation network; Family medical history; hippocampus; Magnetic resonance imaging; Medical imaging; Mental disorders; Metabolites; Morbidity; Mortality; Neurobiology; Neuroimaging; onset polarity; Pathophysiology; proton magnetic resonance spectroscopy; Spectrum analysis; Greece; bipolar disorder; predominant polarity; hippocampus; cingulate cortex; proton magnetic resonance spectroscopy; emotion regulation network; onset polarity
• ISSN: 2075-4418; 2075-4418
• DOI: 10.3390/diagnostics14111170

Although magnetic resonance spectroscopy (MRS) has provided in vivo measurements of brain chemical profiles in bipolar disorder (BD), there are no data on clinically and therapeutically important onset polarity (OP) and predominant polarity (PP). We conducted a proton MRS study in BD polarity subphenotypes, focusing on emotion regulation brain regions. Forty-one euthymic BD patients stratified according to OP and PP and sixteen healthy controls (HC) were compared. 1H-MRS spectra of the anterior and posterior cingulate cortex (ACC, PCC), left and right hippocampus (LHIPPO, RHIPPO) were acquired at 3.0T to determine metabolite concentrations. We found significant main effects of OP in ACC mI, mI/tNAA, mI/tCr, mI/tCho, PCC tCho, and RHIPPO tNAA/tCho and tCho/tCr. Although PP had no significant main effects, several medium and large effect sizes emerged. Compared to HC, manic subphenotypes (i.e., manic-OP, manic-PP) showed greater differences in RHIPPO and PCC, whereas depressive suphenotypes (i.e., depressive-OP, depressive-PP) in ACC. Effect sizes were consistent between OP and PP as high intraclass correlation coefficients (ICC) were confirmed. Our findings support the utility of MRS in the study of the neurobiological underpinnings of OP and PP, highlighting that the regional specificity of metabolite changes within the emotion regulation network consistently marks both polarity subphenotypes.