Behavioral and Transcriptomic Changes Following Brain-Specific Loss of Noradrenergic Transmission.

Noradrenaline (NE) plays an integral role in shaping behavioral outcomes including anxiety/depression, fear, learning and memory, attention and shifting behavior, sleep-wake state, pain, and addiction. However, it is unclear whether dysregulation of NE release is a cause or a consequence of maladaptive orientations of these behaviors, many of which associated with psychiatric disorders. To address this question, we used a unique genetic model in which the brain-specific vesicular monoamine transporter-2 (VMAT2) gene expression was removed in NE-positive neurons disabling NE release in the entire brain. We engineered VMAT2 gene splicing and NE depletion by crossing floxed VMAT2 mice with mice expressing the Cre-recombinase under the dopamine ß-hydroxylase (DBH) gene promotor. In this study, we performed a comprehensive behavioral and transcriptomic characterization of the VMAT2DBHcre KO mice to evaluate the role of central NE in behavioral modulations. We demonstrated that NE depletion induces anxiolytic and antidepressant-like effects, improves contextual fear memory, alters shifting behavior, decreases the locomotor response to amphetamine, and induces deeper sleep during the non-rapid eye movement (NREM) phase. In contrast, NE depletion did not affect spatial learning and memory, working memory, response to cocaine, and the architecture of the sleep-wake cycle. Finally, we used this model to identify genes that could be up- or down-regulated in the absence of NE release. We found an up-regulation of the synaptic vesicle glycoprotein 2c (SV2c) gene expression in several brain regions, including the locus coeruleus (LC), and were able to validate this up-regulation as a marker of vulnerability to chronic social defeat. The NE system is a complex and challenging system involved in many behavioral orientations given it brain wide distribution. In our study, we unraveled specific role of NE neurotransmission in multiple behavior and link it to molecular underpinning, opening future direction to understand NE role in health and disease.

Diabetes Mellitus Is Associated With Poor In-Hospital and Long-Term Outcomes in Young and Midlife Stroke Survivors.

Background The incidence of ischemic stroke has increased among adults aged 18 to 64 years, yet little is known about relationships between specific risk factors and outcomes. This study investigates in-hospital and long-term outcomes in patients with stroke aged <65 years with preexisting diabetes mellitus. Methods and Results Consecutive patients aged <65 years admitted to comprehensive stroke centers for acute ischemic stroke between 2003 and 2013 were identified from the Ontario Stroke Registry. Multinomial logistic regression was used to estimate adjusted odds ratio (OR [95% CI]) of in-hospital mortality or direct discharge to long-term or continuing care. Cox proportional hazards regression was used to estimate the adjusted hazards ratio (aHR [95% CI]) of long-term mortality, readmission for stroke/transient ischemic attack, admission to long-term care, and incident dementia. Predefined sensitivity analyses examined stroke outcomes among young (aged 18-49 years) and midlife (aged 50-65 years) subgroups. Among 8293 stroke survivors (mean age, 53.6±8.9 years), preexisting diabetes mellitus was associated with a higher likelihood of in-hospital death (adjusted OR, 1.46 [95% CI, 1.14-1.87]) or direct discharge to long-term care (adjusted OR, 1.65 [95% CI, 1.07-2.54]). Among stroke survivors discharged (N=7847) and followed up over a median of 6.3 years, preexisting diabetes mellitus was associated with increased hazards of death (aHR, 1.68 [95% CI, 1.50-1.88]), admission to long-term care (aHR, 1.57 [95% CI, 1.35-1.82]), readmission for stroke/transient ischemic attack (aHR, 1.37 [95% CI, 0.21-1.54]), and incident dementia (aHR, 1.44 [95% CI, 1.17-1.77]). Only incident dementia was not increased for young stroke survivors. Conclusions Focused secondary prevention and risk factor management may be needed to address poor long-term outcomes for patients with stroke aged <65 years with preexisting diabetes mellitus.

Depression and Diabetes Mellitus Multimorbidity Is Associated With Loss of Independence and Dementia Poststroke.

BACKGROUND AND PURPOSE: Many patients with ischemic stroke present with multiple comorbidities that threaten survival and recovery. This study sought to determine the risks of adverse long-term stroke outcomes associated with multimorbid diabetes mellitus and depression. METHODS: Retrospective analysis of prospectively collected data on consecutive patients without premorbid dementia admitted from the community for a first-ever acute ischemic stroke to comprehensive stroke centers across Ontario, Canada (2003-2013). Premorbid histories of diabetes mellitus and depression were ascertained within 5 years before stroke admission. Adjusted hazard ratios (aHR [95% CI]) of admission to long-term care, incident dementia, readmission for stroke or transient ischemic attack and all-cause mortality, over time among those discharged back into the community poststroke. RESULTS: Among 23 579 stroke admissions, n=20 201 were discharged back into the community. Diabetes mellitus and depression were associated with synergistic hazards of admission to long-term care (X2=5.4; P=0.02) over a median follow-up of 5.6 years. This interaction was observed among women specifically; depression multimorbidity showed particularly high hazards of admission to long-term care (aHRDepression=1.57 [1.24-1.98]) and incident dementia (aHRDepression=1.85 [1.40-2.44]) among women with diabetes mellitus. In the whole cohort, diabetes mellitus and depression were associated individually with long-term care admission (aHRDiabetes=1.20 [1.12-1.29]; aHRDepression=1.19 [1.04-1.37]), incident dementia (aHRDiabetes=1.14 [1.06-1.23]; aHRDepression=1.27 [1.08-1.49]), stroke/transient ischemic attack readmission (aHRDiabetes=1.18 [1.10-1.26]; aHRDepression=1.24 [1.07-1.42]), and all-cause mortality (aHRDiabetes=1.29 [1.23-1.36]; aHRDepression=1.16 [1.05-1.29]). CONCLUSIONS: The risks of dementia and needing long-term care in the years after surviving a stroke were particularly elevated among women when premorbid diabetes mellitus and depression occurred together. Long-term stroke recovery strategies might target high-risk patients with mood and metabolic multimorbidity.

Serum osteocalcin is associated with subjective stress in people with depression and type 2 diabetes.

BACKGROUND: Low serum osteocalcin is a risk factor for type 2 diabetes mellitus (T2DM), and osteocalcin release from bone is associated with an acute stress response in mice. Both diabetes and stress are associated with depression. Here, we assess relationships between serum osteocalcin, depression and subjective stress in people with T2DM. METHODS: Participants with T2DM (HbA1c above 6.4 %, impaired fasting glucose or impaired glucose tolerance) were assessed for a major depressive episode using the research version of the Structured Clinical Interview for DSM-5 depression criteria (SCID-5RV). Subjective stress over the past month was assessed using the Perceived Stress Scale (PSS). Serum carboxylated (cOCN) and fully decarboxylated (dcOCN) osteocalcin were assayed from fasting morning blood by commercial enzyme-linked immunosorbent assay. RESULTS: Among 95 participants (mean age 62.4 ± 9.9, 51 % women), 22 % were experiencing a depressive episode (9 men, 12 women). The presence of a depressive episode was not associated with dcOCN or cOCN concentrations; however, higher concentrations of cOCN were associated with higher PSS scores in participants with depression (r = 0.585, p = 0.005). In an analysis of covariance model controlling for age, sex, body mass index, glycemic control (glycosylated hemoglobin), insulin resistance (homeostatic model), depression, and antidepressant use, cOCN was associated with PSS scores (F=10.302, p = 0.002), and this relationship was stronger in those with depression (depression × cOCN interaction F=4.978, p = 0.028). Although associations between dcOCN concentrations and PSS scores did not reach significance, the same trend seen with cOCN concentrations was observed in participants with depression for dcOCN (r=0.365, p=0.10), and for a depression × dcOCN interaction associated with PSS scores in the whole group (F=2.165, p = 0.15). CONCLUSIONS: Osteocalcin is a neuroendocrine marker associated with perceived chronic stress among people with T2DM experiencing a depressive episode.

Psychiatric morbidity and cervical cancer screening: a retrospective population-based case-cohort study.

BACKGROUND: Cervical cancer screening reduces disease-specific mortality. This study aimed to estimate whether bipolar disorder or schizophrenia is associated with disparities in cervical cancer screening rates. METHODS: This was a retrospective population-based matched case-cohort study of community-dwelling women aged 19-69 in Ontario using linked health administrative databases. We used odds ratios (ORs), hazards ratios and rate ratios (RRs) adjusted for demographic characteristics and relevant comorbidities to compare cervical cancer screening outcomes between women with a diagnosis of bipolar disorder or schizophrenia to women without that history matched on key demographic characteristics, between 2003 and 2015. RESULTS: In total, 1 245 457 women were identified for inclusion in the analyses, 119 948 with a diagnosis of bipolar disorder or schizophrenia, and 1 125 509 without. Over a median follow-up duration of 12.5 years, women with the exposure were 36% less likely to be screened (OR 0.64, 95% confidence interval [CI] 0.64-0.65) than those without, and they took longer to undergo screening (median 18.98 mo v. 16.63 mo; χ2 = 3718.2, p < 0.001). They were also screened less frequently (median 6.16 yr v. 4.69 yr per screen; RR 0.85, 95% CI 0.84-0.85). These effects were consistent after we excluded the 86 475 women (6.9%) with suspected major depressive disorder, and they were larger for the 59 141 women (4.7%) not attached to a family physician. INTERPRETATION: Women with bipolar disorder or schizophrenia were less likely to undergo cervical cancer screening, their screening was delayed, and they were screened at a lower rate compared to women without this psychiatric history. This practice gap suggests a need to further address barriers to screening, including access to a family physician, among women with bipolar disorder or schizophrenia.

Sleep-Wake Cycle Dysfunction in the TgCRND8 Mouse Model of Alzheimer's Disease: From Early to Advanced Pathological Stages.

In addition to cognitive decline, individuals affected by Alzheimer's disease (AD) can experience important neuropsychiatric symptoms including sleep disturbances. We characterized the sleep-wake cycle in the TgCRND8 mouse model of AD, which overexpresses a mutant human form of amyloid precursor protein resulting in high levels of ß-amyloid and plaque formation by 3 months of age. Polysomnographic recordings in freely-moving mice were conducted to study sleep-wake cycle architecture at 3, 7 and 11 months of age and corresponding levels of ß-amyloid in brain regions regulating sleep-wake states were measured. At all ages, TgCRND8 mice showed increased wakefulness and reduced non-rapid eye movement (NREM) sleep during the resting and active phases. Increased wakefulness in TgCRND8 mice was accompanied by a shift in the waking power spectrum towards fast frequency oscillations in the beta (14-20 Hz) and low gamma range (20-50 Hz). Given the phenotype of hyperarousal observed in TgCRND8 mice, the role of noradrenergic transmission in the promotion of arousal, and previous work reporting an early disruption of the noradrenergic system in TgCRND8, we tested the effects of the alpha-1-adrenoreceptor antagonist, prazosin, on sleep-wake patterns in TgCRND8 and non-transgenic (NTg) mice. We found that a lower dose (2 mg/kg) of prazosin increased NREM sleep in NTg but not in TgCRND8 mice, whereas a higher dose (5 mg/kg) increased NREM sleep in both genotypes, suggesting altered sensitivity to noradrenergic blockade in TgCRND8 mice. Collectively our results demonstrate that amyloidosis in TgCRND8 mice is associated with sleep-wake cycle dysfunction, characterized by hyperarousal, validating this model as a tool towards understanding the relationship between ß-amyloid overproduction and disrupted sleep-wake patterns in AD.

ßCTF-correlated burst of hippocampal TNFα occurs at a very early, pre-plaque stage in the TgCRND8 mouse model of Alzheimer's disease.

Tumor necrosis factor-alpha (TNFα) regulates neuronal excitability. We investigated whether alterations in the level of TNFα occur at a time point that precedes the reported seizure-associated hyperexcitability of hippocampal networks in pre-plaque models of Alzheimer's disease (AD). Western blot and ELISA experiments indicated a significant increase in hippocampal TNFα expression in 1-month-old TgCRND8 mice that correlated with levels of the ß-C-terminal fragment (ßCTF) of amyloid-ß protein precursor. CD11b labeling indicated changes in microglial morphology toward an activated state, suggesting that these cells may be a putative source of the observed TNFα increase during this pre-symptomatic stage of AD-like pathology.

Immune marker CD68 correlates with cognitive impairment in normally aged rats.

The relationship between heightened neuroinflammation and cognitive decline in the normally aged brain is still debatable, as most data are derived from insult-related models. Accordingly, the aim of the current study was to determine whether a link could be established for 2 immune markers at the post-transcriptional level; CD68 and MHC-II, in a normally aged (24-month-old) rat population discriminated for their learning abilities. Using the Morris Water Maze (MWM) task, aged rats were divided into aged learning-impaired (AI) or -unimpaired (AU) groups. Western immunoblots of hippocampal tissue revealed a significant increase of CD68 in AI rats compared to the AU group. Moreover, up-regulated CD68 expression correlated with increased latency times in the MWM task. Immunofluorescence for CD68 revealed intense staining in the white matter regions and CA3 subregion of the hippocampus in the AI group. Despite expression of MHC-II in the AI group, no correlation was found. Overall, these data suggest that CD68 could play a role associated with cognitive decline in a subgroup of the normally aged population.