Lactate flux dysfunction in patients with bipolar disorder: preliminary insights from ultra-high field 7T MRSI during
Michele A Bertocci1, Rasim S Diler1,2
1University of Pittsburgh School of Medicine, Pittsburgh, PA, United States.
Introduction:
The symptoms of bipolar disorder (BD) may be characterized as disruptions in energy metabolism, and neural energy availability may serve as a mechanistic marker of BD. Lactate, the end product of glycolysis, is a poorly understood neural energy source that may contribute to the neural dysfunction underlying BD.
Methods:
We aimed to assess precuneus lactate availability during an emotion processing task and during rest in a sample of participants with well-characterized, pediatric-onset BD (n = 17) and healthy participants (n = 8), using 7-Tesla (7T) magnetic resonance spectroscopic imaging (MRSI). The mean age of the participants was 19.2 years (3.8).
Results:
In this small sample, we observed that the difference in precuneus lactate availability between the emotion processing task and rest (e.g., lactate flux) was greater in participants with BD [mean = 0.014 (0.041)] than in healthy controls (HCs) [mean = -0.033 (0.028), t(17) = 2.64, p = 0.017, Cohen's d = 1.3, Bayes factor10 = 3.528]. In addition, we found that this greater difference in lactate availability (task-rest) in participants with BD, particularly those with lower precuneus lactate availability at rest, demonstrated a trend related to elevated depression scores (r = 0.459, p = 0.055, Bayes factor10 = 1.617).
Discussion:
These results suggest, for the first time, using ultra-high-field strength MRSI with a high signal-to-noise ratio, that lactate flux is dysfunctional in well-characterized BD. Our findings highlight the importance of lactate as a mechanistic marker of BD, which may be used to develop novel treatment options.
