Resting state and activated brain glutamate-glutamine, brain lactate, cognition, and psychopathology among males with schizophrenia: A 3 Tesla proton magnetic resonance spectroscopic (1H-MRS) study

Abstract

Background: Research on glutamate (Glu) in schizophrenia has so far been inconclusive. Based on preclinical studies on Glu lactate interaction, researchers have now focused on brain lactate level as a sign of major pathology, including cognitive dysfunctions in the brain. Our study aimed to examine changes at resting and activated states in brain lactate and Glu-glutamine (Glx) at the anterior cingulate cortex (ACC) in schizophrenia.

Methods: A hospital-based prospective study was conducted with twenty-two male cases of schizophrenia and matched healthy controls (HCs). Positive and Negative Syndrome Scale (PANSS), Montreal Cognitive Assessment (MoCA), and Stroop tasks were administered among patients. Brain lactate and Glx at ACC were measured at resting state and during the Stroop test with proton magnetic resonance spectroscopy (1H-MRS) both at baseline and at remission and once among HC.

Result: Though MoCA scores improved significantly (P < 0.001) at remission from baseline among cases, repeated-measures analysis of variance (RM-ANOVA) did not find a significant time effect for Glx (P = 0.82) and lactate (P = 0.30) among cases from baseline to remission. Glx and lactate changed differently from baseline to remission.

Conclusion: Our study did not find significant differences in Glx and lactate between schizophrenia patients and HC. No significant time effect on Glx and lactate was observed from baseline to remission among schizophrenia cases. Different changes observed in Glx and lactate from baseline to remission require replication in future studies with larger sample size, longer follow-up period, and multivoxel MR assessment.

Keywords: 1H-MRS; Glx; MoCA; PANSS; Stroop; glutamate; glutamine; lactate; psychopathology; spectroscopy.

Figure 1

Estimated marginal means of MoCA, Glx, and lactate. MoCA: Montreal Cognitive Assessment, GlxBR: Glx at baseline resting state, GluBS: Glx at baseline during Stroop task, GluRR: Glx at remission resting state, GluRS: Glx at remission during Stroop task, LactateBR: lactate at baseline resting state, LactateBS: lactate at baseline during the Stroop task, LactateRR: lactate at remission resting state, LactateRS: lactate at remission during the Stroop task