Pituitary gland volumes in bipolar disorder

Enlarged pituitary gland volume: a possible state rather than trait marker of psychotic disorders

BACKGROUND

Enlarged pituitary gland volume could be a marker of psychotic disorders. However, previous studies report conflicting results. To better understand the role of the pituitary gland in psychosis, we examined a large transdiagnostic sample of individuals with psychotic disorders.

METHODS

The study included 751 participants (174 with schizophrenia, 114 with schizoaffective disorder, 167 with psychotic bipolar disorder, and 296 healthy controls) across six sites in the Bipolar-Schizophrenia Network on Intermediate Phenotypes consortium. Structural magnetic resonance images were obtained, and pituitary gland volumes were measured using the MAGeT brain algorithm. Linear mixed models examined between-group differences with controls and among patient subgroups based on diagnosis, as well as how pituitary volumes were associated with symptom severity, cognitive function, antipsychotic dose, and illness duration.

RESULTS

Mean pituitary gland volume did not significantly differ between patients and controls. No significant effect of diagnosis was observed. Larger pituitary gland volume was associated with greater symptom severity (F = 13.61, p = 0.0002), lower cognitive function (F = 4.76, p = 0.03), and higher antipsychotic dose (F = 5.20, p = 0.02). Illness duration was not significantly associated with pituitary gland volume. When all variables were considered, only symptom severity significantly predicted pituitary gland volume (F = 7.54, p = 0.006).

CONCLUSIONS

Although pituitary volumes were not increased in psychotic disorders, larger size may be a marker associated with more severe symptoms in the progression of psychosis. This finding helps clarify previous inconsistent reports and highlights the need for further research into pituitary gland-related factors in individuals with psychosis.

The Morphology of the Pituitary Gland: A Meta-Analysis with Implications for Diagnostic Imaging

The objective of this meta-analysis was to present transparent data on the morphology of the pituitary gland (PG) using the available data in the literature. The main online medical databases, such as PubMed, Embase, Scopus, and Web of Science, were searched to gather all relevant studies regarding PG morphology. The mean overall volume of the PG was found to be 597.23 mm³ (SE = 28.81). The mean overall height of the PG was established to be 5.64 mm (SE = 0.11). The mean overall length of the PG was found to be 9.98 mm (SE = 0.26). In the present study, the PG's overall morphology and morphometric features were analyzed. Our results showed that, on average, females from Asia have the highest volume of PG (706.69 mm³), and males from Europe have the lowest (456.42 mm³). These values are crucial to be aware of because they represent the normal average properties of the PG, which may be used as reference points when trying to diagnose potential pathologies of this gland. Furthermore, the present study's results prove how the PG's size decreases with age. The results of the present study may be helpful for physicians, especially surgeons, performing procedures on the PG.

Shared postulations between bipolar disorder and polycystic ovary syndrome pathologies

INTRODUCTION

Women with bipolar disorder (BD) present a high prevalence of polycystic ovary syndrome (PCOS) and other reproductive disorders even before diagnosis or treatment of the disease. Postulations on the potential molecular mechanisms of comorbid PCOS in women with BD remain limited to influence of medications and need further extension.

OBJECTIVES

This review focuses on evidence suggesting that common metabolic and immune disorders may play an important role in the development of BD and PCOS.

RESULTS

The literature covered in this review suggests that metabolic and immune disorders, including the dysfunction of the hypothalamic-pituitary-adrenal axis, chronic inflammatory state, gut microbial alterations, adipokine alterations and circadian rhythm disturbance, are observed in patients with BD and PCOS. Such disorders may be responsible for the increased prevalence of PCOS in the BD population and indicate a susceptibility gene overlap between the two diseases. Current evidence supports postulations of common metabolic and immune disorders as endophenotype in BD as well as in PCOS.

CONCLUSIONS

Metabolic and immune disorders may be responsible for the comorbid PCOS in the BD population. The identification of hallmark metabolic and immune features common to these two diseases will contribute to the clarification of the effect of BD on the reproductive endocrine function and development of symptomatic treatments targeting the biomarkers of the two diseases.

Structural neuroimaging and predominant polarity in patients with type 1 bipolar disorder from Antioquia

INTRODUCTION

Predominant polarity (PP) has been proposed as a specifier of bipolar disorder (BD) due to its relationship with clinical and prognostic variables. It is possible that this is due to a different underlying neurobiology, in such a way that the changes found by structural nuclear magnetic resonance imaging (sMRI) in BD are different and specific.

OBJECTIVES

To explore findings of structural neuroimaging in patients with BD type I (BD-I) according to PP.

METHODS

Cross-sectional study that evaluated 77 patients with BD-I using the DIGS interview. PP was established using the operative definition of two-thirds of all affective episodes throughout life to classify PP as manic (MPP), depressive (DPP) or indeterminate (IPP). MRI was performed during the euthymia phase to measure intracranial structures. The data obtained was analysed using a linear regression model adjusted for confounding variables (drug use, alcohol use, psychoactive substance use) and were compared between the three groups finding the standardised mean difference (SMD).

RESULTS

Differences with adequate effect size were found in three brain structures after adjusting for confounding variables, specifically in the right fusiform gyrus and the left lingual gyrus, which were greater in the DPP group than in the MPP group (SMD = 0.92; 95% CI = 0.34-1.49 and SMD = 0.78; 95% CI = 0.21-1.35). Likewise, in the right thalamus, it was shown to be greater in the IPP group compared to MPP group (SMD 0.89, 95% CI = 0.31-1.46).

CONCLUSIONS

A reduction in the thickness of the right fusiform gyrus and the left lingual gyrus, as well as the right thalamic volume was observed in patients with BD-I with PPM, which supports the hypothesis that PP has a plausible neurobiological correlate and could have potential utility as a BD specifier.

Structural Neuroimaging and Predominant Polarity in Patients with Type 1 Bipolar Disorder from Antioquia

INTRODUCTION

Predominant polarity (PP) has been proposed as a specifier of bipolar disorder (BD) due to its relationship with clinical and prognostic variables. It is possible that this is due to a different underlying neurobiology, in such a way that the changes found by structural nuclear magnetic resonance imaging (sMRI) in BD are different and specific.

OBJECTIVES

To explore findings of structural neuroimaging in patients with BD type I (BD-I) according to PP.

METHODS

Cross-sectional study that evaluated 77 patients with BD-I using the DIGS interview. PP was established using the operative definition of two-thirds of all affective episodes throughout life to classify PP as manic (MPP), depressive (DPP) or indeterminate (IPP). MRIwas performed during the euthymia phase to measure intracranial structures. The data obtained was analysed using a linear regression model adjusted for confounding variables (drug use, alcohol use, psychoactive substance use) and were compared between the three groups finding the standardised mean difference (SMD).

RESULTS

Differences with adequate effect size were found in three brain structures after adjusting for confounding variables, specifically in the right fusiform gyrus and the left lingual gyrus, which were greater in the DPP group than in the MPP group (SMD = 0.92; 95% CI = 0.34 to 1.49 and SMD = 0.78; 95% CI = 0.21 to 1.35). Likewise, in the right thalamus, it was shown to be greater in the IPP group compared to MPP group (SMD 0.89, 95% CI = 0.31 to 1.46).

CONCLUSIONS

A reduction in the thickness of the right fusiform gyrus and the left lingual gyrus, as well as the right thalamic volume was observed in patients with BD-I with PPM, which supports the hypothesis that PP has a plausible neurobiological correlate and could have potential utility as a BD specifier.

Hypothalamus enlargement in mood disorders

OBJECTIVE

The purpose of this study was to determine, in vivo, whether the hypothalamus volume is reduced in patients with mood disorders.

METHODS

The cross-sectional study included 20 unmedicated (MDDu) and 20 medicated patients with major depressive disorder, 21 patients with bipolar disorder, and 23 controls. Twenty of the controls were matched to the MDDu. Seven Tesla, T1-weighted magnetic resonance images were acquired and processed using methods specifically developed for high-precision volumetry of the hypothalamus.

RESULTS

An overall group difference was observed for the left hypothalamus volume corrected for intracranial volume. Planned contrasts identified that the left hypothalamus was approximately 5% larger in each patient group compared with the control group. A paired t-test with the 20 matched pairs of MDDu and controls and without correction for covariates confirmed the larger left hypothalamus volume in MDDu.

CONCLUSIONS

Contrary to our expectations, the hypothalamus volume was increased in patients with uni- and bipolar affective disorders. The effect was left-sided and independent of medication status or statistical correction for covariates. Supported by emerging evidence that the stress response may be related to structural and functional asymmetry in the brain, our finding suggests a crucial role of the hypothalamus in mood disorders.

Neurobiology and Therapeutic Potential of Cyclooxygenase-2 (COX-2) Inhibitors for Inflammation in Neuropsychiatric Disorders

Neuropsychiatric disorders, such as depression, bipolar disorder, schizophrenia, obsessive-compulsive disorder, and neurodevelopmental disorders such as autism spectrum disorder, are associated with significant illness burden. Accumulating evidence supports an association between these disorders and inflammation. Consequently, anti-inflammatory agents, such as the cyclooxygenase-2 inhibitors, represent a novel avenue to prevent and treat neuropsychiatric illness. In this paper, we first review the role of inflammation in psychiatric pathophysiology including inflammatory cytokines' influence on neurotransmitters, the hypothalamic-pituitary-adrenal axis, and microglial mechanisms. We then discuss how cyclooxygenase-2-inhibitors influence these pathways with potential therapeutic benefit, with a focus on celecoxib, due to its superior safety profile. A search was conducted in PubMed, Embase, and PsychINFO databases, in addition to Clinicaltrials.gov and the Stanley Medical Research Institute trial registries. The results were presented as a narrative review. Currently available outcomes for randomized controlled trials up to November 2017 are also discussed. The evidence reviewed here suggests cyclooxygenase-2 inhibitors, and in particular celecoxib, may indeed assist in treating the symptoms of neuropsychiatric disorders; however, further studies are required to assess appropriate illness stage-related indication.

Pituitary gland shrinkage in bipolar disorder: The role of gender

BACKGROUND

Hyperactivity of the Hypothalamic-Pituitary-Adrenal Axis (HPAA) has been consistently reported in mood disorders. However, only few studies investigated the Pituitary gland (PG) in Bipolar Disorder (BD) and the results are so far contrasting. Therefore, the aim of this study is to explore the integrity of the PG as well as the role of gender and the impact of clinical measurements on this structure in a sample of BD patients compared to healthy controls (HC).

METHODS

34 BD patients and 41 HC underwent a 1.5 T MRI scan. PG volumes were manually traced for all subjects. Psychiatric symptoms were assessed by means of the Brief Psychiatry Rating Scale, the Hamilton Depression Rating Scale and the Bech Rafaelsen Mania Rating Scale.

RESULTS

We found decreased PG volumes in BD patients compared to HC (F = 24.9, p < 0.001). Interestingly, after dividing the sample by gender, a significant PG volume decrease was detected only in female BD patients compared to female HC (F = 9.1, p < 0.001), but not in male BD compared to male HC (F = -0.12, p = 0.074). No significant correlations were observed between PG volumes and clinical variables.

CONCLUSIONS

Our findings suggest that BD patients have decreased PG volumes, probably due to the long-term hyperactivity of the HPAA and to the consequent strengthening of the negative feedback control towards the PG volume itself. This alteration was particularly evident in females, suggesting a role of gender in affecting PG volumes in BD. Finally, the absence of significant correlations between PG volumes and clinical variables further supports that PG disruption is a trait feature of BD, being independent of symptoms severity and duration of treatment.

Pituitary gland in Bipolar Disorder and Major Depression: Evidence from structural MRI studies: Special Section on "Translational and Neuroscience Studies in Affective Disorders". Section Editor, Maria Nobile MD, PhD. This Section of JAD focuses on the relevance of translational and neuroscience studies in providing a better understanding of the neural basis of affective disorders. The main aim is to briefly summarise relevant research findings in clinical neuroscience with particular regards to specific innovative topics in mood and anxiety disorders

BACKGROUND

The function of the hypothalamo-pituitary-adrenal axis (HPA) has been widely investigated in mood disorders based on its role in regulating stress response. Particularly, Magnetic Resonance Imaging (MRI) reports have explored pituitary gland (PG) in both bipolar disorder (BD) and major depressive disorder (MDD). In this context, the present review summarizes the results from MRI studies with the final aim of commenting on the presence of common or distinct PG structural alterations between these two disabling illnesses.

METHODS

A bibliographic search on PUBMED of all MRI studies exploring PG volumes in BD and MDD as well as first-degree relatives (RELs) from 2000 up to October 2016 was performed.

RESULTS

Following the screening process of the available literature it can be said that a) PG enlargement has been found in both BD and MDD, therefore potentially representing a common neurobiological marker characterizing mood disorders, and b) PG volumes are moderated by age and sex in both illnesses, although the direction and the extent of this moderation are still not fully clear.

LIMITATIONS

Few MRI studies with heterogeneous results.

CONCLUSIONS

These hypotheses must be taken with caution especially because the heterogeneity of the results of the studies reviewed does not allow for a definite answer about the role of PG in affective disorders. Therefore, larger longitudinal studies investigating PG volumes in BD and MDD patients at the early phases of the illness, by considering females and males separately, are needed to further corroborate these findings.

The HPA axis in bipolar disorder: Systematic review and meta-analysis

OBJECTIVES

To provide a quantitative and qualitative synthesis of the available evidence on the role of Hypothalamic-Pituitary-Adrenal (HPA) axis in the pathophysiology of Bipolar Disorder (BD).

METHODS

Meta-analysis and meta-regression of case-control studies examining the levels of cortisol, ACTH, CRH levels. Systematic review of stress reactivity, genetic, molecular and neuroimaging studies related to HPA axis activity in BD.

RESULTS

Forty-one studies were included in the meta-analyses. BD was associated with significantly increased levels of cortisol (basal and post-dexamethasone) and ACTH, but not of CRH. In the meta-regression, case-control differences in cortisol levels were positively associated with the manic phase (p=0.005) and participants' age (p=0.08), and negatively with antipsychotics use (p=0.001). Reviewed studies suggest that BD is associated with abnormalities of stress-related molecular pathways in several brain areas. Variants of HPA axis-related genes seem not associated with a direct risk of developing BD, but with different clinical presentations. Also, studies on unaffected relatives suggest that HPA axis dysregulation is not an endophenotype of BD, but seems related to environmental risk factors, such as childhood trauma. Progressive HPA axis dysfunction is a putative mechanism that might underlie the clinical and cognitive deterioration of patients with BD.

CONCLUSIONS

BD is associated with dysfunction of HPA axis activity, with important pathophysiological implications. Targeting HPA axis dysfunctions might be a novel strategy to improve the outcomes of BD.