Long-term Effects of a Brief Mindfulness Intervention Versus a Health Enhancement Program for Treating Depression and Anxiety in Patients Undergoing Hemodialysis: A Randomized Controlled Trial

Background:

Depression and anxiety affect approximately 50% of patients with kidney failure receiving hemodialysis and are associated with decreased quality of life and increased risk of hospitalization and mortality. A Brief Mindfulness Intervention (BMI) may be promising in treating depressive and anxiety symptoms in this population, but the long-term sustainability of the intervention’s effects is unknown.

Objective:

We previously conducted a randomized controlled trial (RCT; n = 55) comparing an 8-week BMI with an active control (Health Enhancement Program [HEP]) for patients receiving dialysis, with depression and/or anxiety. Here, we examine the 6-month follow-up data to determine the long-term sustainability of BMI versus HEP in reducing (1) depressive symptoms, (2) anxiety symptoms, and (3) the efficacy of BMI versus HEP in reducing the likelihood of hospitalization.

Design:

In this study, we analyzed 6-month follow-up data from an 8-week assessor-blinded parallel RCT, which evaluated the efficacy of a BMI against an active control, HEP, in patients receiving hemodialysis with symptoms of depression and/or anxiety.

Setting:

The study took place at hemodialysis centers in 4 tertiary-care hospitals in Montreal, Canada.

Participants:

Participants included adults aged ≥18 years who were receiving in-center hemodialysis 3 times per week and had symptoms of depression and/or anxiety as indicated by a score ≥6 on the Patient Health Questionnaire–9 (PHQ-9) and/or the General Anxiety Disorder–7 (GAD-7).

Methods:

Participants were randomized to the treatment arm (BMI) or the active control arm (HEP) and completed assessments at baseline, 8 weeks, and 6-month follow-up. Depression was assessed using the PHQ-9, and anxiety was assessed by the GAD-7. Hospitalization rates were assessed using medical chart information.

Results:

We observed significant decrease in depression scores over 6 months in both BMI and HEP groups, with no significant difference between groups. Anxiety scores significantly decreased over 6 months, but only in the BMI group. Brief Mindfulness Intervention and Health Enhancement Program were comparable in terms of hospitalization rates.

Limitations:

The limitations of our study include the modest sample size and lack of a third arm such as a waitlist control.

Conclusions:

Our results suggest that the beneficial effects of BMI and HEP for improving mood disorder symptoms in patients receiving dialysis persist at 6-month follow-up. Both interventions showed sustained effects for depressive symptoms, but BMI may be more useful in this population given its efficacy in reducing anxiety symptoms as well.

Trial registration:

Prior to recruitment, the trial had been registered (ClinicalTrials.gov Identifier: NCT03406845).

Extrasynaptic Communication

Streams of action potentials or long depolarizations evoke a massive exocytosis of transmitters and peptides from the surface of dendrites, axons and cell bodies of different neuron types. Such mode of exocytosis is known as extrasynaptic for occurring without utilization of synaptic structures. Most transmitters and all peptides can be released extrasynaptically. Neurons may discharge their contents with relative independence from the axon, soma and dendrites. Extrasynaptic exocytosis takes fractions of a second in varicosities or minutes in the soma or dendrites, but its effects last from seconds to hours. Unlike synaptic exocytosis, which is well localized, extrasynaptic exocytosis is diffuse and affects neuronal circuits, glia and blood vessels. Molecules that are liberated may reach extrasynaptic receptors microns away. The coupling between excitation and exocytosis follows a multistep mechanism, different from that at synapses, but similar to that for the release of hormones. The steps from excitation to exocytosis have been studied step by step for the vital transmitter serotonin in leech Retzius neurons. The events leading to serotonin exocytosis occur similarly for the release of other transmitters and peptides in central and peripheral neurons. Extrasynaptic exocytosis occurs commonly onto glial cells, which react by releasing the same or other transmitters. In the last section, we discuss how illumination of the retina evokes extrasynaptic release of dopamine and ATP. Dopamine contributes to light-adaptation; ATP activates glia, which mediates an increase in blood flow and oxygenation. A proper understanding of the workings of the nervous system requires the understanding of extrasynaptic communication.

Effects of Mindfulness-Based Cognitive Therapy on Peripheral Markers of Stress and Inflammation in Older-Adults With Depression and Anxiety: A Parallel Analysis of a Randomized Controlled Trial

Background: Depression and anxiety are prevalent in older-adults and often difficult to treat: up to 55% of patients are unresponsive to pharmacotherapy. Mindfulness-Based Cognitive Therapy (MBCT) is a promising treatment, however, its biological mechanisms remain unknown in older-adults. Methods: We examined if, in older-adults, decreased depression and anxiety symptoms after MBCT are associated with changes in the expression levels of C-reactive protein, Interleukin-1β, Monocyte chemoattractant protein-1 and mineralocorticoid receptor compared to treatment as usual (TAU). Older-adults (age ≥60) with depression and anxiety were randomized to MBCT or treatment as usual. Gene expression levels from blood samples were measured using quantitative polymerase chain reaction (n = 37) at baseline and after 8-weeks of MBCT or TAU. Results: As previously published, we found a significant reduction in symptoms of depression F (1, 35) = 10.68, p = 0.002, partial η² = 0.23 and anxiety F (1, 35) = 9.36, p = 0.004, partial η² = 0.21 in geriatric participants following MBCT compared to TAU. However, the expression levels of measured genes were not significantly different between groups and were not associated with changes in depression and anxiety symptoms. Conclusion: Our results suggest that the symptom reduction following MBCT in older-adults may not be accompanied by changes in the stress-response and inflammatory pathways. Future research should address other potential biological alterations associated to MBCT that may be responsible for the reduction of symptoms.

Continuation Sessions of Mindfulness-Based Cognitive Therapy (MBCT-C) vs. Treatment as Usual in Late-Life Depression and Anxiety: An Open-Label Extension Study

OBJECTIVES

Mindfulness-based cognitive therapy (MBCT) is a novel treatment for depression. Our published randomized controlled trial shows that MBCT improves symptoms of late-life depression (LLD) and anxiety (LLA). We now examine whether continuation sessions of MBCT (MBCT-C) can prevent LLD/LLA symptom recurrence.

METHODS/DESIGN

Following an 8-week MBCT intervention, we compared patients who attended open-label weekly 1-hour MBCT-C for another 26 weeks (n = 10) vs those who did not (n = 17) for change in depressive and anxiety symptoms.

RESULTS

While there were no significant differences between groups on depressive or anxiety symptom severities between 8- and 34- weeks (Cohen's d = 0.045), we observed a small clinical effect of MBCT-C on symptoms of anxiety (d = 0.29).

CONCLUSIONS

These preliminary results suggest that MBCT-C may be somewhat beneficial for symptoms of LLA, but not for LLD. Healthcare providers should consider what is clinically feasible before investing time and resources into MBCT-C in older adults with depression and/or anxiety.

Rare susceptibility variants for bipolar disorder suggest a role for G protein-coupled receptors

Bipolar disorder (BD) is a prevalent mood disorder that tends to cluster in families. Despite high heritability estimates, few genetic susceptibility factors have been identified over decades of genetic research. One possible interpretation for the shortcomings of previous studies to detect causative genes is that BD is caused by highly penetrant rare variants in many genes. We explored this hypothesis by sequencing the exomes of affected individuals from 40 well-characterized multiplex families. We identified rare variants segregating with affected status in many interesting genes, and found an enrichment of deleterious variants in G protein-coupled receptor (GPCR) family genes, which are important drug targets. Furthermore, we showed targeted downstream GPCR dysregulation for some of the variants that may contribute to disease pathology. Particularly interesting was the finding of a rare and functionally relevant nonsense mutation in the corticotropin-releasing hormone receptor 2 (CRHR2) gene that tracked with affected status in one family. By focusing on rare variants in informative families, we identified key biochemical pathways likely implicated in this complex disorder.

Atorvastatin in the treatment of Lithium-induced nephrogenic diabetes insipidus: the protocol of a randomized controlled trial

BACKGROUND

Lithium is the gold-standard treatment for bipolar disorder, is highly effective in treating major depressive disorder, and has anti-suicidal properties. However, clinicians are increasingly avoiding lithium largely due to fears of renal toxicity. Nephrogenic Diabetes Insipidus (NDI) occurs in 15-20% of lithium users and predicts a 2-3 times increased risk of chronic kidney disease (CKD). We recently found that use of statins is associated with lower NDI risk in a cross-sectional study. In this current paper, we describe the methodology of a randomized controlled trial (RCT) to treat lithium-induced NDI using atorvastatin.

METHODS

We will conduct a 12-week, double-blind placebo-controlled RCT of atorvastatin for lithium-induced NDI at McGill University, Montreal, Canada. We will recruit 60 current lithium users, aged 18-85, who have indicators of NDI, which we defined as urine osmolality (UOsm) < 600 mOsm/kg after 10-h fluid restriction. We will randomize patients to atorvastatin (20 mg/day) or placebo for 12 weeks. We will examine whether this improves measures of NDI: UOsm and aquaporin (AQP2) excretion at 12-week follow-up, adjusted for baseline.

RESULTS

Not applicable.

CONCLUSION

The aim of this clinical trial is to provide preliminary data about the efficacy of atorvastatin in treating NDI. If successful, lithium could theoretically be used more safely in patients with a reduced subsequent risk of CKD, hypernatremia, and acute kidney injury (AKI). If future definitive trials confirm this, this could potentially allow more patients to benefit from lithium, while minimizing renal risk.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02967653 . Registered in February 2017.

End-of-Life Care Preferences in Patients with Severe and Persistent Mental Illness and Chronic Medical Conditions: A Comparative Cross-Sectional Study

OBJECTIVES

Physicians rarely engage severe and persistent mental illness (SPMI) patients in end-of-life care discussion despite an increased risk of debilitating medical illnesses and mortality. Access to quality palliative care and medical assistance in dying (MAID) has become a priority in Canada and many jurisdictions. In this study, we compared SPMI and chronic medically ill (CMI) patients' end-of-life care preferences and comfort level with end-of-life care discussion, and identified potential predictors of interest in MAID.

DESIGN

Comparative cross-sectional study.

SETTING

Hospital-based.

PARTICIPANTS

We recruited 106 SPMI and 95 CMI patients at the Jewish General Hospital, Canada. Patients aged ≥40 years, without severe cognitive impairment, able to communicate in English or French and provide written informed consent were included.

MEASUREMENTS

Attitudes towards pain management, palliative sedation, MAID, and artificial life support were collected with the Health Care Preferences Questionnaire. Adjusted odd ratios (aOR) were calculated for each end-of-life care intervention. Comfort with discussion was rated on a Likert scale. A stepwise regression analysis was performed to identify predictors of interest in MAID.

RESULTS

SPMI was not correlated to any end-of-life care intervention, except for MAID where SPMI patients were less likely to support its use (aOR: 0.48, 95% CI: 0.25-0.94, p = 0.03). Religiosity was also correlated with interest in MAID (aOR: 0.14, 95% CI: 0.06-0.31, p < 0.001). Patients in both groups were comfortable talking about end-of-life care.

CONCLUSIONS

SPMI patients are able to voice their end-of-life care preferences, and contrary to some fears, do not want MAID more than CMI patients.

Repression of Astrocytic Connexins in Cortical and Subcortical Brain Regions and Prefrontal Enrichment of H3K9me3 in Depression and Suicide

BACKGROUND

Major depressive disorder has been associated with dysfunctional astrocytic networks. The underlying causes, extent, and consequences of such dysfunctions remain to be characterized. Astrocyte-astrocyte communication occurs principally through gap junction channels primarily formed by connexin 30 and 43 (CX30 and CX43). We previously reported decreased connexin expression in the prefrontal cortex of depressed suicides. In the present study, we investigated whether these changes are mediated by epigenetic regulation, and expanded gene expression quantifications to other cortical and subcortical regions to assess the regional distribution of connexion disruptions in depressed suicides.

METHODS

The expression of CX30 and CX43 was measured by real-time PCR in samples of neocortex (Brodmann areas 4 and 17), cerebellar cortex, mediodorsal thalamus, and caudate nucleus of 22 depressed suicides and 22 matched sudden-death controls. Chromatin immunoprecipitation was used to measure enrichment levels of the repressive chromatin mark H3K9me3 in the prefrontal cortex.

RESULTS

We found a consistent downregulation of connexin genes in all regions examined, except in the cerebellum where an increase in the expression of CX30 was measured and using chromatin immunoprecipitation we observed an enrichment of H3K9me3 for both Cx30 and Cx43 in the prefrontal cortex.

CONCLUSIONS

Our study shows widespread astrocytic CX gene repression in depressed suicides that is mediated, at least in part, through epigenetic mechanisms. Taken together, these findings support the notion of widespread cerebral astrocytic dysfunction in major depressive disorder.

Evidence for increased microglial priming and macrophage recruitment in the dorsal anterior cingulate white matter of depressed suicides

Despite increasing evidence supporting the neuroinflammatory theory of depression, little is known about cerebral macrophages in individuals suffering from major depression. In the present study, we investigated the morphology and distribution of cells immunostained for the macrophage-specific marker ionized calcium binding adaptor molecule 1 (IBA1) in the dorsal anterior cingulate cortex (dACC) white matter of middle-aged depressed suicides and matched non-psychiatric controls. This region is known for its implication in mood disorders, and its white matter compartment was previously found to display hypertrophic astrocytes in depressed suicides. Distributions of IBA1-immunoreactive (IBA-IR) microglial phenotypes were assessed using stereology and cell morphometry, and blood vessels were characterized as being intimately associated with either a high or a low density of IBA1-IR amoeboid-like cells. Total densities of IBA1-IR microglia did not differ between depressed suicides and controls. However, a finer analysis examining relative proportions of microglial phenotypes revealed that the ratio of primed over ramified ("resting") microglia was significantly increased in depressed suicides. Strikingly, the proportion of blood vessels surrounded by a high density of macrophages was more than twice higher in depressed suicides than in controls, and this difference was strongly significant. Consistent with these observations, gene expression of IBA1 and MCP-1, a chemokine involved in the recruitment of circulating monocytes, was significantly upregulated in depressed suicides. Furthermore, mRNA for CD45, a marker enriched in perivascular macrophages, was also significantly increased in samples from depressed suicides. An increase compared to controls was also observed in the proportion of blood vessels surrounded by a high density of CD45-IR cells, but this difference did not reach significance. These histological and molecular data suggest the recruitment of monocytes in dACC white matter of depressed suicides, although it cannot be excluded that other types of macrophages (including microglia) account for the observed accumulation of macrophages closely associated with blood vessels. Altogether, these findings suggest that the previously reported depression- and suicide-associated increases in circulating pro-inflammatory cytokines may be associated with low-grade cerebral neuroinflammation involving the recruitment of circulating monocytes.

Morphometric characterization of microglial phenotypes in human cerebral cortex

Background

Microglia can adopt different morphologies, ranging from a highly ramified to an amoeboid-like phenotype. Although morphological properties of microglia have been described in rodents, little is known about their fine features in humans. The aim of this study was to characterize the morphometric properties of human microglia in gray and white matter of dorsal anterior cingulate cortex (dACC), a region implicated in behavioral adaptation to neuroinflammation. These properties were compared to those of murine microglia in order to gain a better appreciation of the differences displayed by these cells across species.

Methods

Postmortem dACC samples were analyzed from 11 individuals having died suddenly without any history of neuroinflammatory, neurodegenerative, nor psychiatric illness. Tissues were sectioned and immunostained for the macrophage marker Ionized calcium binding adaptor molecule 1 (IBA1). Randomly selected IBA1-immunoreactive (IBA1-IR) cells displaying features corresponding to commonly accepted microglial phenotypes (ramified, primed, reactive, amoeboid) were reconstructed in 3D and all aspects of their morphologies quantified using the Neurolucida software. The relative abundance of each morphological phenotype was also assessed. Furthermore, adult mouse brains were similarly immunostained, and IBA1-IR cells in cingulate cortex were compared to those scrutinized in human dACC.

Results

In human cortical gray and white matter, all microglial phenotypes were observed in significant proportions. Compared to ramified, primed microglia presented an average 2.5 fold increase in cell body size, with almost no differences in branching patterns. When compared to the primed microglia, which projected an average of six primary processes, the reactive and amoeboid phenotypes displayed fewer processes and branching points, or no processes at all. In contrast, the majority of microglial cells in adult mouse cortex were highly ramified. This was also the case following a postmortem interval of 43 hours. Interestingly, the morphology of ramified microglia was strikingly similar between species.

Conclusions

This study provides fundamental information on the morphological features of microglia in the normal adult human cerebral cortex. These morphometric data will be useful for future studies of microglial morphology in various illnesses. Furthermore, this first direct comparison of human and mouse microglia reveals that these brain cells are morphologically similar across species, suggesting highly conserved functions.