A comparison of neurometabolites between remitted bipolar disorder and depressed bipolar disorder: A proton magnetic resonance spectroscopy study

Exploring neurometabolic alterations in bipolar disorder with suicidal ideation based on proton magnetic resonance spectroscopy and machine learning technology

Bipolar disorder (BD) is associated with a high risk of suicide. We used proton magnetic resonance spectroscopy (1H-MRS) to detect biochemical metabolite ratios in the bilateral prefrontal white matter (PWM) and hippocampus in 32 BD patients with suicidal ideation (SI) and 18 BD patients without SI, identified potential brain biochemical differences and used abnormal metabolite ratios to predict the severity of suicide risk based on the support vector machine (SVM) algorithm. Furthermore, we analyzed the correlations between biochemical metabolites and clinical variables in BD patients with SI. There were three main findings: (1) the highest classification accuracy of 88% and an area under the curve of 0.9 were achieved in distinguishing BD patients with and without SI, with N-acetyl aspartate (NAA)/creatine (Cr), myo-inositol (mI)/Cr values in the bilateral PWM, NAA/Cr and choline (Cho)/Cr values in the left hippocampus, and Cho/Cr values in the right hippocampus being the features contributing the most; (2) the above seven features could be used to predict Self-rating Idea of Suicide Scale scores (r = 0.4261, p = 0.0302); and (3) the level of neuronal function in the left hippocampus may be related to the duration of illness, the level of membrane phospholipid catabolism in the left hippocampus may be related to the severity of depression, and the level of inositol metabolism in the left PWM may be related to the age of onset in BD patients with SI. Our results showed that the combination of multiple brain biochemical metabolites could better predict the risk and severity of suicide in patients with BD and that there was a significant correlation between biochemical metabolic values and clinical variables in BD patients with SI.

Glutamatergic and N-Acetylaspartate Metabolites in Bipolar Disorder: A Systematic Review and Meta-Analysis of Proton Magnetic Resonance Spectroscopy Studies

The exact neurobiological mechanisms of bipolar disorder (BD) remain unknown. However, some neurometabolites could be implicated, including Glutamate (Glu), Glutamine (Gln), Glx, and N-acetylaspartate (NAA). Proton Magnetic Resonance Spectroscopy (¹H-MRS) allows one to quantify these metabolites in the human brain. Thus, we conducted a systematic review and meta-analysis of the literature to compare their levels between BD patients and healthy controls (HC). The main inclusion criteria for inclusion were ¹H-MRS studies comparing levels of Glu, Gln, Glx, and NAA in the prefrontal cortex (PFC), anterior cingulate cortex (ACC), and hippocampi between patients with BD in clinical remission or a major depressive episode and HC. Thirty-three studies were included. NAA levels were significantly lower in the left white matter PFC (wmPFC) of depressive and remitted BD patients compared to controls and were also significantly higher in the left dorsolateral PFC (dlPFC) of depressive BD patients compared to HC. Gln levels were significantly higher in the ACC of remitted BD patients compared to in HC. The decreased levels of NAA of BD patients may be related to the alterations in neuroplasticity and synaptic plasticity found in BD patients and may explain the deep white matter hyperintensities frequently observed via magnetic resonance imagery.

Neurometabolic alterations in bipolar disorder with anxiety symptoms: A proton magnetic resonance spectroscopy study of the prefrontal whiter matter

To identify the pathophysiological mechanism of bipolar disorder (BD) patients with anxiety symptoms, we analyzed the differences of brain biochemical metabolism in BD patients with and without anxiety symptoms. We collected 39 BD patients who had been untreated with drugs in one month and were divided into the anxiety symptoms group (20 cases) and non-anxiety symptoms group (19 cases) according to whether they had anxiety symptoms. We used proton magnetic resonance spectroscopy (¹H-MRS) to detect the biochemical metabolite ratios of the prefrontal whiter matter (PWM) in all patients. The right PWM mI/Cr ratios in BD patients with anxiety symptoms were higher than those in BD patients without anxiety symptoms and the Cho/Cr ratios in the left PWM were negatively correlated with age and age of onset in BD patients with anxiety symptoms. These findings indicated that BD patients with anxiety symptoms have increased levels of inositol metabolism in the right PWM. Furthermore, the level of membrane phospholipid catabolism in the left PWM of BD patients with anxiety symptoms decreased with increasing age and onset age. Our results provide some references for the pathophysiological mechanism in BD patients with anxiety symptoms.

Association of altered thyroid hormones and neurometabolism to cognitive dysfunction in unmedicated bipolar II depression

BACKGROUND

The underlying mechanism of cognitive impairment in bipolar II depression (BD II) remains unclear. Studies show disturbances of the hypothalamus-pituitary-thyroid (HPT) axis are suspected of correlating to brain neurometabolic alterations and cognitive deficits in psychiatric disorders. While, the nature of their inter-relationships in BD II depression remain enigmatic.

METHODS

106 patients with unmedicated BD II depression and 100 healthy controls underwent cognitive function assessment using Trail Making Test, Part-A (TMT-A), Digit Symbol Substitution Test (DSST), and Semantic Verbal Fluency testing (SVF). Of those, 69 patients and 53 healthy controls had serum thyroid hormone levels measured including free tri-iodothyronine (FT3), total tri-iodothyronine (TT3), free thyroxin (FT4), total thyroxin (TT4) and thyroid-stimulating hormone (TSH). Additionally, 79 of the patients and 76 of the healthy controls underwent proton magnetic resonance spectroscopy (H-MRS) to obtain ratios of N-acetyl aspartate to creatine (NAA/Cr) and choline-containing compounds to creatine (Cho/Cr) in the prefrontal cortex (PFC), anterior cingulate cortex (ACC) and thalamus. Finally, association and multiple regression analysis were conducted to investigate their inter-relationships.

RESULTS

Patients with BD II depression showed significantly lower DSST and verbal fluency scores and longer completion time of TMT-A than did healthy controls. The FT3, TT3, and TSH levels of the BD cohort significantly decreased, while their FT4 levels increased. We also found significantly lower NAA/Cr ratios in the PFC and higher NAA/Cr ratios in the left thalamus of patients with BD II depression than in healthy controls. Furthermore, association analysis showed that increased FT4 negatively correlated to DSST and SVF, while increased FT4 correlation significantly with increasing TSH and DSST. Multiple regression analyses revealed relationships between TSH and NAA in the left PFC and the left thalamus, while correlating to SVF testing within the BD II depression cohort.

CONCLUSIONS

Our results demonstrate coinciding thyroid hormone abnormalities, cognitive dysfunction, and neurometabolic alterations of the PFC-thalamic circuitry occur in an early course of BD II depression. Further understanding of the interaction between thyroid-stimulating hormone and NAA/Cr of PFC-thalamic circuitry may shed light on the etiology of associated cognitive impairment.

Magnetic resonance spectroscopy and its application in colorectal cancer diagnosis and screening: A narrative review

There are several slightly invasive methods to detect colorectal carcinoma (CRC) including colonoscopy and sigmoidoscopy; but there is no noninvasive, accurate screening test. It is recommended to initiate screening at the age of 50 for non-familial CRC. Laboratory tests are routinely suggested if internal observation and imaging are recommended for further evaluation. Spectroscopic-based imaging, such as magnetic resonance spectroscopy (MRS) is an interesting and promising tool with the potential to be an alternative to some minimally invasive procedures, such as biopsy. Accordingly, MRS might be a suitable substitution for invasive methods, such as colonoscopy. This article aimed to review the studies that have evaluated the MRS technique as a screening tool in CRC.

Serum copper and zinc levels correlate with biochemical metabolite ratios in the prefrontal cortex and lentiform nucleus of patients with major depressive disorder

BACKGROUND

Previous studies have demonstrated that copper and zinc metabolism are associated with the development of major depressive disorder (MDD). Abnormal copper and zinc levels may be related to neurotransmission and biochemical metabolism in the brains of MDD patients, especially in the prefrontal cortex (PFC) and lentiform nucleus (LN). However, the mechanism of how copper and zinc levels contribute to neural metabolism in MDD patients remains to be deciphered. This study aimed to correlate copper and zinc levels with biochemical metabolite ratios in the PFC and LN of MDD patients.

METHOD

Twenty-nine MDD patients and thirty-two healthy control (HC) volunteers were enrolled in this study. Proton magnetic resonance spectroscopy (¹H-MRS) was used to determine the levels of the N-acetylaspartate (NAA), choline (Cho) and creatine (Cr) in the brain, and specifically in the PFC and LN regions. Serum copper and zinc levels were measured using atomic emission spectrometry (AES). Afterwards, copper and zinc levels were correlated with biochemical metabolite ratios in the PFC and LN regions of the brain.

RESULTS

Higher serum copper and lower serum zinc levels with higher copper/zinc ratios were observed in MDD patients. NAA/Cr ratios in the PFC of MDD patients were lower compared to HC volunteers. In MDD patients, serum copper levels were negatively correlated with NAA/Cr ratios in the right PFC and right LN, while copper/zinc ratios were negatively correlated with NAA/Cr ratios in the right LN. No significant differences in serum copper and zinc levels with NAA/Cr ratios in the left PFC and left LN were observed in MDD patients.

CONCLUSION

Our findings suggest that higher serum copper and lower serum zinc levels may contribute to neuronal impairment by affecting neuronal biochemical metabolite ratios in the right PFC and right LN of MDD patients. Abnormal copper and zinc levels may play an important role in the pathophysiology of MDD.

Altered biochemical metabolism and its lateralization in the cortico-striato-cerebellar circuit of unmedicated bipolar II depression

OBJECTIVES

Evidence of the relationship between neurometabolic changes in the cortico-striato-cerebellar (CSC) circuit and bipolar disorder (BD) is still limited. To elucidate the pathogenesis of BD, we investigated the underlying neurometabolic changes and their effect on CSC lateralization circuits in unmedicated patients with bipolar II depression.

METHODS

Forty unmedicated participants with bipolar II depression and forty healthy controls underwent proton magnetic resonance spectroscopy (¹H-MRS). We obtained bilateral metabolic ratios of N-acetylaspartate (NAA)/creatine (Cr) and choline (Cho)/Cr in the prefrontal white matter (PWM), anterior cingulate cortex (ACC), basal ganglia (BG) and the cerebellum. Metabolic ratios were characterized using a laterality index (LI) for left-right asymmetry.

RESULTS

Overall, aberrant lateralization in the CSC circuit was characteristic in patients with bipolar II depression. Patients with bipolar II depression showed significantly lower NAA/Cr ratios in the left PWM, right ACC, left BG and left cerebellum when compared with the healthy controls. For bipolar II depression, we found lower NAA/Cr LI in the PWM, BG, and cerebellum, higher NAA/Cr LI in the ACC, and higher Cho/Cr LI in the BG and cerebellum when compared to the standard value (1.0). For healthy controls, we found lower NAA/Cr LI only in the BG and higher Cho/Cr LI in the cerebellum when compared to 1.0.

LIMITATIONS

As a cross-sectional study with a small sample size, progressive changes and complex metabolic interactions with treatment were not observed.

CONCLUSIONS

Our findings suggest that abnormal biochemical metabolism with aberrant lateralization in the CSC circuit may be an underlying pathophysiology of bipolar II depression.

Clinical features of bipolar disorder with idiopathic basal ganglia calcification: a review of case reports in the literature

Although idiopathic basal ganglia calcification (IBGC) is associated with various neuropsychiatric disturbances including several cases of bipolar disorder (BD), there has been no systematic review of clinical features of patients with BD and comorbid IBGC. We undertook a literature search to identify case reports of these patients. Most cases showed complex syndromes comprising not only mood disturbance but also cognitive disability and motor symptoms limited to depressive state and had favorable treatment response. These patients should have a careful and repeated psychiatric, neurological, and cognitive assessment to determine an optimal diagnostic and treatment approaches at each clinical stage.

Correlations between working memory impairment and neurometabolites of prefrontal cortex and lenticular nucleus in patients with major depressive disorder

BACKGROUND

The mechanism of working memory (WM) impairment in MDD remains unclear. We aimed to find out the mechanism by using neuropsychological tests and proton magnetic resonance spectroscopy (1H-MRS).

METHODS

31 MDD patients and 31 healthy controls were recruited in our study. The WM performance and neurometabolite ratios of prefrontal cortex (PFC) and lenticular nucleus (LN) between two groups were evaluated and compared. And the correlations between abnormal neurometabolite ratios and WM dysfunction were computed.

RESULTS

Scores of SDMT, DST(forwards), VRS and 2-back Task(accuracy rate) in MDD were lower than HCs. NAA/Cr ratios of bilateral PFC in MDD were significantly lower than HCs, while no significant differences showed in NAA/Cr ratios of LN and Cho/Cr, mI/Cr values of the bilateral PFC and LN between two groups. And for MDD patients, NAA/Cr ratios in the right PFC were positively correlated with scores of DST (Forwards).

CONCLUSIONS

Our findings suggest that depressed patients may have impairments in working memory, including phonological loop, visual-spatial sketchpad, episodic buffer and central executive. And the impairment of verbal WM and WM capacity may be associated with the abnormal neurometabolites in the right PFC.