Can variation in hypothalamic-pituitary-adrenal (HPA)-axis activity explain the relationship between depression and cognition in bipolar patients?

Cortisol to Dehydroepiandrosterone Sulphate Ratio and Executive Function in Bipolar Disorder

INTRODUCTION

Bipolar disorder (BD) is associated with impairment in cognitive domains such as verbal memory and executive functions. Very few studies have assessed dehydroepiandrosterone sulphate (DHEA-S) in BD and its relation to cognitive functioning despite evidence showing its regulatory effects on glucocorticoid action. The aim of our study was to explore the association of cortisol, DHEA-S, and cortisol to DHEA-S ratio with visuospatial memory and executive functioning in BD.

METHODS

Cognitive performance of 60 bipolar I patients and 30 healthy subjects was evaluated by using Cambridge Neuropsychological Test Automated Battery tasks targeting visuospatial memory (spatial recognition memory) and executive functions (planning [Stockings of Cambridge; SOC] and attentional set shifting [ID/ED]). Morning serum cortisol and DHEA-S levels were measured in patients. Main effects of cortisol, DHEA-S, and cortisol/DHEA-S ratio for each neurocognitive task were explored in multiple regression analyses correcting for demographic and clinical parameters as well as treatment-related factors (current use of antipsychotic and mood stabilizer medication).

RESULTS

Bipolar patients showed poorer performance than healthy subjects in planning and attentional set shifting but not in visuospatial memory. Cortisol to DHEA-S ratio predicted worse performance in planning (SOC).

CONCLUSIONS

This is the first study to assess memory and executive function in BD in relation to DHEA-S and cortisol to DHEA-S ratio. We report an association of cortisol to DHEA-S ratio with worse performance in planning in bipolar I patients, which warrants further investigation.

Differential association of cortisol with visual memory/learning and executive function in Bipolar Disorder

The association of cortisol with cognition has been understudied in Bipolar Disorder (BD); available evidence is inconsistent while it is unknown whether cortisol's effects vary across neurocognitive domains implicating different brain structures. This study aimed to examine the association of cortisol with two cognitive tasks targeting visual memory and executive function (planning) in BD, related to the hippocampus and prefrontal lobe, respectively. Cambridge Neuropsychological Test Automated Battery (CANTAB) tasks targeting paired associative learning (PAL) and planning (Stockings of Cambridge; SOC) were administered to 60 BD type I patients. Basal serum cortisol was also measured. Higher cortisol was associated with worse performance in PAL, but not SOC, after controlling for gender, education, illness duration and treatment with mood stabilizers. This is the first study to examine the association of cortisol with neurocognitive function in BD while controlling for clinicodemographic and treatment-related factors. We found a significant association of cortisol with hippocampal-related visual memory/learning but not with prefrontal lobe-related executive function, suggesting domain-specific underlying mechanisms of cognitive dysfunction in BD. Future studies should further explore cortisol's brain structure-specific effects on cognitive functioning in BD.

At the heart of the matter: Cardiovascular health challenges among incarcerated women

Many factors appear to contribute to an increased risk for cardiovascular disease (CVD) among incarcerated women. Imprisonment is associated with a bodyweight gain and an increased prevalence of overweight and obesity. Inadequate physical activity and unhealthy nutrition further contribute to this positive energy balance. Classical CVD risk factors are common, including hypertension, diabetes mellitus, metabolic syndrome, and smoking. Moreover, imprisonment is associated with an increased incidence of mental health issues, such as depression and anxiety, with coping mechanisms, including substance abuse, being frequently adopted. Specific attitudes in the correctional environment, including hunger strikes, bullying, abuse and solitary confinement, are effectors of cardiovascular and mental ill-health. Furthermore, the plethora of psychological stressors induces an accelerated aging process, paired with CVD risk. Communicable diseases, mainly human immunodeficiency virus, opportunistic infections and inadequate sunlight exposure increase cardiovascular dysregulation. Health care needs associated with the female sex are not always met, adding to the frustration and compromised well-being. All these factors act independently and cumulatively, increasing CVD risk among incarcerated women.

Modeling lifetime abuse and cardiovascular disease risk among women

BACKGROUND

Cardiovascular disease (CVD) is one of the most significant health challenges facing women today. Abuse is a serious gendered issue also affecting the health of women. Despite beginning evidence that abuse may increase the risk of CVD among women, causal pathways linking abuse to CVD have received little attention. Our purpose was to test Scott-Storey's conceptual model showing direct and indirect pathways through which lifetime abuse severity may affect women's CVD risk.

METHODS

Using data collected from a community sample of 227 Canadian women who had left an abusive partner, we conducted structural equation modeling with latent growth curve analysis using a phantom variable approach to test the direct effects of severity of lifetime abuse on CVD risk (indicated by measures of systolic and diastolic blood pressure) as well as its indirect effects through CVD risk behaviors and through women's initial level of depressive symptoms and the observed rate of change in their depressive symptoms over time.

RESULTS

Women in this sample had above average CVD risk factors (i.e., smoking, overweight/obesity, depressive symptoms, high blood pressure) in comparison to women in the general population. Further, CVD risk behaviors increased with severity of lifetime abuse and remained present long after leaving the abusive relationship. Results of the tested model provide preliminary evidence supporting many of the hypothesized pathways by which severity of lifetime abuse can increase CVD risk among women; the model fit the data reasonably well explaining 41% of the variance in CVD risk.

CONCLUSIONS

Findings support the growing recognition of the long-term effects of lifetime abuse on cardiovascular health, suggest important implications for clinicians working with women, and provide a novel approach for studying the concept of cumulative lifetime abuse through the use of a phantom variable.

Psychological Wellbeing and Healthy Aging: Focus on Telomeres

Stress and depression are known to modulate the aging process, and might also affect telomere biology. In fact, exposure to some biochemical pathways involved in stress-related depression may contribute to an ‘‘accelerated aging” phenotype, as well as the incidence of age-related diseases, including metabolic disorders and dementia. Basic studies support the notion that the telomere and telomerase system plays a pivotal role in the aging process and disease promotion. Interestingly, short and dysfunctional telomeres are associated with reduced lifespan, as shown in animal models. In this context, telomeres are very sensitive to stress, mindset, and lifestyle, and their rescue may be sufficient to restore cell and organism viability. This mini-review discusses conceptual models of healthy and active aging and their relationship with telomere biology and mental health.

The correlation between longitudinal changes in hypothalamic-pituitary-adrenal (HPA)-axis activity and changes in neurocognitive function in mixed-state bipolar II disorder

INTRODUCTION

In this study, we aim to determine 1) the differences in cortisol in patients with bipolar II disorder (BD-II) and control subjects and 2) the correlation between cortisol levels and cognitive function in patients with BD-II during a 24-week follow-up period.

METHODS

We recruited a total of 32 BD-II patients and 30 healthy control subjects. The BD-II patients were assessed for clinical severity and serum cortisol level at baseline and at weeks 8, 16, and 24. The Brief Assessment of Cognition in Affective Disorders (BACA) was adopted to evaluate cognitive function at baseline and endpoint (week 24). Meanwhile, we assessed the controls for serum cortisol level and BACA at baseline.

RESULTS

We observed that the BD-II group had a higher serum cortisol level and lower BACA composite scores compared with the healthy controls at baseline. A significant correlation was found between changes in Verbal Fluency, a subset of BACA, and changes in serum cortisol level after the 24-week follow-up, controlling for age, gender, years of education, and clinical severity (P<0.001).

CONCLUSION

We propose that serum cortisol may be involved in the psychopathological mechanisms of cognitive decline in BD-II.

Does the diurnal cycle of cortisol explain the relationship between physical performance and cognitive function in older adults?

Background

Regular physical activity is a promising strategy to treat and prevent cognitive decline. The mechanisms that mediate these benefits are not fully clear but physical activity is thought to attenuate the harmful effects of chronic psychological stress and hypercortisolism on cognition. However, the circadian pattern of cortisol secretion is complex and it is not known which aspects are most closely associated with increased cognitive function and better physical performance. This is the first study to simultaneously measure cognitive function, the diurnal cycle of salivary cortisol and physical performance in older adults, without cognitive impairment (n = 30) and with amnestic Mild Cognitive Impairment (aMCI) (n = 30).

Results

Regression analysis showed that better cognitive function was associated with better physical performance. A greater variance in cortisol levels across the day from morning to evening was associated with better cognitive function and physical performance.

Conclusions

The results support the idea that a more dynamic cortisol secretion pattern is associated with better cognitive function and physical performance even in the presence of cognitive impairment, but our results could not confirm a mediating role in this relationship.

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.

Inflammation: a mechanism of depression?

In recent decades, major depression has become more prevalent and research has shown that immune activation and cytokine production may be involved. This review is mainly focused on the contribution of inflammation to depression. We first briefly introduce the inflammatory biomarkers of depression, then discuss the sources of cytokines in the brain, and finally describe the neuroimmunological mechanisms underlying the association between inflammation and depression.

Cortisol awakening response and spatial working memory in man: a U-shaped relationship

OBJECTIVE

The association between hypothalamic-pituitary-adrenal (HPA)-axis function and cognition has long been investigated. An inverted U-shaped relationship has been described between various measures of HPA-axis function and neuropsychological performance in animals and man. Work with glucocorticoid receptor manipulation has corroborated these findings, with particular effects observed in relation to spatial working memory (SWM). As HPA-axis dysfunction is frequently found in patients with psychiatric illness, research in this area has potential implications for the treatment of the commonly observed cognitive impairment in such disorders. Here, we present the results of a pilot study examining the relationship between cortisol awakening response (CAR) and cognitive functions known to be susceptible to HPA-axis manipulation.

METHODS

Nineteen healthy male volunteers were recruited, and their CAR and performance in a task of SWM were assessed.

RESULTS

A highly significant quadratic relationship was observed between the CAR and SWM error rate (R(2)=0.63, p=0.001).

CONCLUSION

We provide novel evidence supporting the existence of an inverted U-shaped relationship between corticosteroid levels and cognitive function in humans.

Biomarkers in bipolar disorder: a positional paper from the International Society for Bipolar Disorders Biomarkers Task Force

Although the etiology of bipolar disorder remains uncertain, multiple studies examining neuroimaging, peripheral markers and genetics have provided important insights into the pathophysiologic processes underlying bipolar disorder. Neuroimaging studies have consistently demonstrated loss of gray matter, as well as altered activation of subcortical, anterior temporal and ventral prefrontal regions in response to emotional stimuli in bipolar disorder. Genetics studies have identified several potential candidate genes associated with increased risk for developing bipolar disorder that involve circadian rhythm, neuronal development and calcium metabolism. Notably, several groups have found decreased levels of neurotrophic factors and increased pro-inflammatory cytokines and oxidative stress markers. Together these findings provide the background for the identification of potential biomarkers for vulnerability, disease expression and to help understand the course of illness and treatment response. In other areas of medicine, validated biomarkers now inform clinical decision-making. Although the findings reviewed herein hold promise, further research involving large collaborative studies is needed to validate these potential biomarkers prior to employing them for clinical purposes. Therefore, in this positional paper from the ISBD-BIONET (biomarkers network from the International Society for Bipolar Disorders), we will discuss our view of biomarkers for these three areas: neuroimaging, peripheral measurements and genetics; and conclude the paper with our position for the next steps in the search for biomarkers for bipolar disorder.

Angiotensin receptor blockers for bipolar disorder

Studies have suggested that the brain renin angiotensin system (RAS) regulates cerebral flow, autonomic and hormonal systems, stress, innate immune response and behavior, being implicated in several brain disorders such as major depression, Parkinson's and Alzheimer's disease. The angiotensin II receptor subtype 1 (AT1R) is distributed in brain regions responsible for the control of stress response through peripheral and central sympathetic hyperactivation as well as in the hypothalamic paraventricular region, areas known for the release of several neurotransmitters related to inflammatory response facilitation. This relationship leads to the assumption that AT1R might be the receptor most related to the central deleterious actions of angiotensin II. New evidences from clinical studies have shown a possible role for RAS in the pathogenesis of bipolar disorder (BD), a multifactorial disorder with acknowledged presence of neuronal damage via oxidative stress in brain areas such as hippocampus, prefrontal cortex and striatum. Given the studies highlighting AT1R activation as a central pro-inflammatory pathway and, conversely, the involvement of inflammatory response in the pathogenesis of BD; this paper hypothesizes the use of AT1R antagonists for BD management and prevention of its neuroprogression, due to their anti-inflammatory and neuroprotective effects.