Neuroendocrine Stress System in Bipolar Disorder

Decreased serum allopregnanolone and progesterone levels in male patients with bipolar disorder and their effects on cognitive functions

The progression of bipolar disorder (BD) is characterized by recurrent episodes of depression, mania, and hypomania, thus affecting the daily functionality of individuals. Previous studies have shown that a large proportion of patients diagnosed with BD who are in clinical remission experience significant functional disorders. The present study aimed to investigate the relationships between cognitive impairment and serum progesterone, allopregnanolone and BDNF levels in male bipolar disorder patients who are in the euthymic period. Our study included 41 euthymic male patients with bipolar disorder and 40 age, sex, body mass index (BMI) and smoking-matched male healthy control subjects. Neuropsychiatric tests such as the Stroop Test TBAG Form, Auditory Verbal Digit Span Test- Form B (VADS-B) and Cancellation Test were administered to all participants, and 5-7 ml of peripheral venous blood sample was taken from all participants. Serum allopregnanolone, progesterone and BDNF levels were also measured in all participants. Serum allopregnanolone and progesterone levels were found to be lower in bipolar patients, and it was observed that the serum level of allopregnanolone decreased as the disease duration increased. The serum BDNF levels were similar between groups. The cognitive functions assessed using the Stroop, VADS-B and cancellation tests were found to be better in healthy subjects. The neurocognitive test performances of all participants were strongly positively correlated with allopregnanolone levels. The present study supports the hypothesis that allopregnanolone acts as an endogenous mood stabilizer.

Prevalence and characteristics of polycystic ovarian syndrome in patients with bipolar disorder

BACKGROUND

Bipolar disorder (BD) is frequently accompanied by endocrine disturbances. We compared the prevalence of polycystic ovary syndrome (PCOS) and related reproductive disorders between drug-naïve BD patients and matched healthy controls (HCs) and between drug-naïve BD patients and BD patients with long-term medication, as well as the clinical metabolic correlates among BD patients.

METHODS

72 drug-naïve BD patients, 98 HCs, and 72 BD patients with long-term medication were recruited in the study. Menstruation was recorded, reproductive hormone levels and metabolic indicators were measured, and a pelvic ultrasound examination was performed via transvaginal sensor for each participant. PCOS was defined using the Rotterdam criteria.

RESULTS

After controlling for demographic variables, drug-naïve BD patients presented higher rates of PCOS than the HCs (OR: 3.02, 95 % CI: 1.09-8.36). Regression analysis showed that long-term treatment with valproate (OR: 3.89, 95 % CI: 1.13-13.37), age (OR: 0.37, 95 % CI: 0.14-0.95), and insulin resistance index (OR: 1.73, 95 % CI: 1.10-12.71) were correlated with PCOS in BD patients.

CONCLUSIONS

Drug-naïve BD patients are susceptible to developing PCOS, and valproate is correlated with increased occurrence and development of PCOS. Therefore, PCOS in BD patients, especially those who use valproate, needs to be investigated and monitored closely by medical personnel.

Hormonal and inflammatory signatures of different mood episodes in bipolar disorder: a large-scale clinical study

BACKGROUND

Bipolar disorder (BD) is characterized by intensive mood fluctuations. While hormones imbalance plays important role in the mood swings, it is unknown whether peripheral hormones profiles could differentiate the manic and depressive mood episodes in BD. In this study, we investigated the changes of various hormones and inflammatory markers across distinct mood episodes of BD in a large clinical study to provide mood episode-specific peripheral biomarkers for BD.

METHODS

A total of 8332 BD patients (n = 2679 depressive episode; n = 5653 manic episode) were included. All patients were in acute state of mood episodes and need hospitalization. A panel of blood tests were performed for levels of sex hormones (serum levels of testosterone, estradiol, and progesterone), stress hormones (adrenocorticotropic hormone and cortisol), and an inflammation marker (C-reactive protein, CRP). A receiver operating characteristic (ROC) curve was used to analyze the discriminatory potential of the biomarkers for mood episodes.

RESULTS

In overall comparison between mood episodes, the BD patients expressed higher levels of testosterone, estradiol, progesterone, and CRP (P < 0.001) and lower adrenocorticotropic hormone (ACTH) level (P < 0.001) during manic episode. The episode-specific changes of testosterone, ACTH, and CRP levels remained between the two groups (P < 0.001) after correction for the confounding factors including age, sex, BMI, occupation, marital status, tobacco use, alcohol consumption, psychotic symptoms, and age at onset. Furthermore, we found a sex- and age-specific impact of combined biomarkers in mood episodes in male BD patients aged ≥ 45 years (AUC = 0.70, 95% CI, 0.634-0.747), not in females.

CONCLUSIONS

While both hormone and inflammatory change is independently associated with mood episodes, we found that the combination of sex hormones, stress hormones and CRP could be more effective to differentiate the manic and depressive episode. The biological signatures of mood episodes in BD patients may be sex- and age-specific. Our findings not only provide mood episode-related biological markers, but also better support for targeted intervention in BD treatments.

Targeting the Arginine Vasopressin V1b Receptor System and Stress Response in Depression and Other Neuropsychiatric Disorders

A healthy stress response is critical for good mental and overall health and promotes neuronal growth and adaptation, but the intricately balanced biological mechanisms that facilitate a stress response can also result in predisposition to disease when that equilibrium is disrupted. The hypothalamic-pituitary-adrenal (HPA) axis neuroendocrine system plays a critical role in the body's response and adaptation to stress, and vasopressinergic regulation of the HPA axis is critical to maintaining system responsiveness during chronic stress. However, exposure to repeated or excessive physical or emotional stress or trauma can shift the body's stress response equilibrium to a "new normal" underpinned by enduring changes in HPA axis function. Exposure to early life stress due to adverse childhood experiences can also lead to lasting neurobiological changes, including in HPA axis function. HPA axis impairment in patients with depression is considered among the most reliable findings in biological psychiatry, and chronic stress has been shown to play a major role in the pathogenesis and onset of depression and other neuropsychiatric disorders. Modulating HPA axis activity, for example via targeted antagonism of the vasopressin V_1b receptor, is a promising approach for patients with depression and other neuropsychiatric disorders associated with HPA axis impairment. Despite favorable preclinical indications in animal models, demonstration of clinical efficacy for the treatment of depressive disorders by targeting HPA axis dysfunction has been challenging, possibly due to the heterogeneity and syndromal nature of depressive disorders. Measures of HPA axis function, such as elevated cortisol levels, may be useful biomarkers for identifying patients who may benefit from treatments that modulate HPA axis activity. Utilizing clinical biomarkers to identify subsets of patients with impaired HPA axis function who may benefit is a promising next step in fine-tuning HPA axis activity via targeted antagonism of the V_1b receptor.