Conditions: Bipolar Depression
Keywords: Bipolar depression
Allocation: NON_RANDOMIZED | Intervention model: SINGLE_GROUP
Enrollment: 72
Healthy volunteers: yes

Brief summary:
This study compared glutamate and other neurometabolites measured by proton magnetic resonance spectroscopy (1H-MRS) in bipolar I and II patients currently depressed with age-matched healthy controls. The study will also compare 1H-MRS of bipolar I and II patients before and after taking a 12-week course of lamotrigine.

The goal of this study was to better understand the neurobiology of bipolar depression and how lamotrigine may therapeutically impact brain function and mood response.

The hypothesis was that in comparison to non-remission participants, bipolar participants who achieve remission (defined as a Montgomery Asberg Depression Rating Scale (MADRS) score \<12 at week 12) associated with lamotrigine monotherapy will exhibit a greater decrease in glutamate (Glu) and an increase in N-acetyl aspartate (NAA), reported as a cerebrospinal fluid (CSF)-corrected absolute concentration percent change from baseline to endpoint in anterior cingulate (AC) and dorsolateral prefrontal cortex (DLPFC).

Detailed description:
Depression is the predominant prevailing mood state in bipolar disorder and bipolar depression is associated with substantial morbidity and mortality. However, in comparison to acute mania, bipolar depression is understudied both from the standpoint of its pathophysiology as well as clinical trials which include FDA-approved treatments. Given this lack of evidence to base guidelines, clinicians and patients are limited as to how best to treat the depressive phase of the illness.

Proton magnetic resonance spectroscopy (1H-MRS) is a valuable, non-invasive method to study in-vivo brain biochemistry. Of the novel imaging paradigms, MRS is uniquely positioned to investigate biochemical mechanism of drug action that is objectively measurable and clinically relevant. As there is increasing interest in glutamatergic dysregulation in mood disorders, this project will utilize 1H-MRS to study glutamate and glutamine levels in brain regions implicated in bipolar disorder (anterior cingulate and dorsolateral prefrontal cortex).

This was a 5-year single-site study of bipolar depression utilizing 1H-MR spectroscopy before and after treatment with lamotrigine. At baseline bipolar depressed subjects and age-matched controls underwent a 1H-MRS at Mayo Clinic in Rochester, Minnesota. The bipolar depressed subjects were then be placed on 12-week, open evaluation of lamotrigine monotherapy. After 12 weeks, the bipolar subjects underwent a second 1H-MRS scan.

Two different MRS sequences were used to measure the brain chemicals in a single 2 x 2 x 2 cm cube located in the center of anterior cingulate cortex: an intermediate echo-time PRESS sequence and a 2D J-resolved averaged PRESS sequence. Spectroscopic data were inspected for quality; subjects whose data were contaminated by artifact were excluded from the study. Spectra were then processed using LCModel to quantify brain chemical levels. Regular brain MRI images were segmented, yielding a map of the amount of CSF in the head. The MRS cube was overlaid onto the CSF map and the fraction of CSF within the cube measured. This measurement was used to "remove" the CSF from the MRS cube giving brain chemical concentrations. The concentrations were then used for statistical analysis.

Note: All of the spectroscopy data are expressed in Institutional Units (IU).

Arms:
arm 1: Subjects underwent proton magnetic resonance spectroscopy (1H-MR) evaluation of medial anterior cingulate cortex (MACC) and left dorsal lateral prefrontal cortex (LDLPC) before and after treatment with Lamotrigine. arm 2: Subjects underwent proton magnetic resonance spectroscopy (1H-MR) evaluation of medial anterior cingulate cortex (MACC) and left dorsal lateral prefrontal cortex (LDLPC).

Interventions: intervention 1: Lamotrigine intervention 2: 1H-MR
Intervention descriptions: intervention 1: 12 week open trial: 25mg/day for 2 weeks, 50mg/day for 2 weeks, 100mg/day for 2 weeks, 200mg/day for 6 weeks. Flexible titration for early response and/or side effects. intervention 2: Proton magnetic resonance spectroscopy (1H-MR) evaluation of medial anterior cingulate cortex (MACC) and left dorsal lateral prefrontal cortex (LDLPC).

Protocol document: