Liver-secreted fluorescent blood plasma markers enable chronic imaging of the microcirculation.

Studying blood microcirculation is vital for gaining insights into vascular diseases. Blood flow imaging in deep tissue is currently achieved by acute administration of fluorescent dyes in the blood plasma. This is an invasive process, and the plasma fluorescence decreases within an hour of administration. Here, we report an approach for the longitudinal study of vasculature. Using a single intraperitoneal or intravenous administration of viral vectors, we express fluorescent secretory albumin-fusion proteins in the liver to chronically label the blood circulation in mice. This approach allows for longitudinal observation of circulation from 2 weeks to over 4 months after vector administration. We demonstrate the chronic assessment of vascular functions including functional hyperemia and vascular plasticity in micro- and mesoscopic scales. This genetic plasma labeling approach represents a versatile and cost-effective method for the chronic investigation of vasculature functions across the body in health and disease animal models.

The role of central serotonergic markers and estradiol changes in perinatal mental health.

OBJECTIVE: Women have an increased risk for mental distress and depressive symptoms in relation to pregnancy and birth. The serotonin transporter (SERT) may be involved in the emergence of depressive symptoms postpartum and during other sex-hormone transitions. It may be associated with cerebrospinal fluid (CSF) levels of the main serotonin metabolite 5-hydroxyindolacetic acid (5-HIAA). In 100 healthy pregnant women, who were scheduled to deliver by cesarean section (C-section), we evaluated 5-HIAA and estradiol contributions to mental distress 5 weeks postpartum. METHODS: Eighty-two women completed the study. CSF collected at C-section was analyzed for 5-HIAA, with high performance liquid chromatography. Serum estradiol concentrations were quantified by liquid chromatography tandem mass spectrometry before C-section and postpartum. Postpartum mental distress was evaluated with the Edinburgh Postnatal Depression Scale (EPDS). Associations between EPDS, 5-HIAA, and Δestradiol were evaluated in linear regression models adjusted for age, parity and SERT genotype. RESULTS: Higher levels of postpartum mental distress symptoms were negatively associated with a large decrease in estradiol concentrations (ßΔE2  = 0.73, p = 0.007) and, on a trend level, positively associated with high antepartum 5-HIAA levels (ß5-HIAA  = 0.002, p = 0.06). CONCLUSION: In a cohort of healthy pregnant women, postpartum mental distress was higher in women with high antepartum 5-HIAA (trend) and lower in women with a large perinatal estradiol decrease. We speculate that high antepartum 5-HIAA is a proxy of SERT levels, that carry over to the postpartum period and convey susceptibility to mental distress. In healthy women, the postpartum return to lower estradiol concentrations may promote mental well-being.

Electro convulsive therapy: Modification of its effect on the autonomic nervous system using anti-cholinergic drugs.

The antidepressant efficacy of electroconvulsive therapy (ECT) is correlated to the quality of the seizure as measured by EEG but has also been linked to the magnitude of changes in hemodynamic variables. Muscarinic receptor antagonists are frequently used in the treatment, and are known to affect the hemodynamic response. We hypothesized that atropine and glycopyrrolate alter the hemodynamic and autonomic hormonal response to ECT. In a randomized, cross-over study design 23 patients received either atropine, glycopyrrolate or placebo before ECT. Hemodynamic variable, EEG and EMG, and blood adrenaline, noradrenaline and pancreatic polypeptide was determined. No geriatric patients were included. Hemodynamic changes with ECT can be divided into three phases: Drop in blood pressure and pulse rate in 1st post-stimulus phase was less when using 1 mg atropine. In 2nd post-stimulus phase atropine gave a higher systolic blood pressure. No differences were seen in hormone levels after ECT in the three interventions. A significant longer tonic clonic seizure was seen in the glycopyrrolate group and a tendency of the same was seen with atropine. The study found that the changes in hemodynamic variables induced by ECT can be altered by concomitant administration of muscarinic receptor antagonist.

The glucagon-like peptide 1 receptor agonist Exendin-4 decreases relapse-like drinking in socially housed mice.

Glucagon-like peptide-1 (GLP-1) is a gut peptide that regulates food intake and glucose metabolism. GLP-1 is also produced and released in the brain, and GLP-1 receptors are expressed in brain regions important for alcohol and drug reward, and for the development of addiction. GLP-1 receptor agonists can decrease alcohol intake acutely in rodents. However, alcohol use disorder is a chronic condition that requires treatments to be effective in promoting abstinence from excessive alcohol consumption over time. Here, we assessed the effect of daily treatment with the GLP-1 receptor agonist Exendin-4 in an assay of relapse-like drinking in socially housed mice. Male C57BL/6NTac mice were allowed continuous access to alcohol without tastant in the home cage for 37days. Then, alcohol bottles were removed and Exendin-4 (1.5µg/kg/day) or saline was administered subcutaneously for 8days during alcohol deprivation. Treatment continued for 8 additional days after reintroducing access to alcohol. A high-precision automated fluid consumption system was used to monitor intake of alcohol and water, drinking kinetics, and locomotor activity. Exendin-4 prevented the deprivation-induced increase in alcohol intake observed in control mice, without significantly affecting total fluid intake, body weight, or locomotor activity. The reduced alcohol intake was caused by a protracted latency to the first drink of alcohol and a reduced number of drinking bouts, while bout size and duration were not affected. The effect was maintained undiminished throughout the treatment period. These findings support the possible use of GLP-1 receptor agonists in the treatment of alcohol use disorder.

The pan-Kv7 (KCNQ) Channel Opener Retigabine Inhibits Striatal Excitability by Direct Action on Striatal Neurons In Vivo.

Central Kv7 (KCNQ) channels are voltage-dependent potassium channels composed of different combinations of four Kv7 subunits, being differently expressed in the brain. Notably, striatal dopaminergic neurotransmission is strongly suppressed by systemic administration of the pan-Kv7 channel opener retigabine. The effect of retigabine likely involves the inhibition of the activity in mesencephalic dopaminergic neurons projecting to the striatum, but whether Kv7 channels expressed in the striatum may also play a role is not resolved. We therefore assessed the effect of intrastriatal retigabine administration on striatal neuronal excitability in the rat determined by c-Fos immunoreactivity, a marker of neuronal activation. When retigabine was applied locally in the striatum, this resulted in a marked reduction in the number of c-Fos-positive neurons after a strong excitatory striatal stimulus induced by acute systemic haloperidol administration in the rat. The relative mRNA levels of Kv7 subunits in the rat striatum were found to be Kv7.2 = Kv7.3 = Kv7.5 > >Kv7.4. These data suggest that intrastriatal Kv7 channels play a direct role in regulating striatal excitability in vivo.

Effect of recombinant erythropoietin on inflammatory markers in patients with affective disorders: A randomised controlled study.

AIM: This study investigated the effect of repeated infusions of recombinant human erythropoietin (EPO) on markers of inflammation in patients with affective disorders and whether any changes in inflammatory markers were associated with improvements on verbal memory. METHODS: In total, 83 patients were recruited: 40 currently depressed patients with treatment-resistant depression (TRD) (Hamilton Depression Rating Scale-17 items (HDRS-17) score >17) (sub-study 1) and 43 patients with bipolar disorder (BD) in partial remission (HDRS-17 and Young Mania Rating Scale (YMRS)⩽14) (sub-study 2). In both sub-studies, patients were randomised in a double-blind, parallel-group design to receive eight weekly intravenous infusions of EPO (Eprex; 40,000IU/ml) or saline (0.9% NaCl). Plasma concentrations of interleukin 6 (IL-6), interleukin 18 (IL-18) and high sensitive c-reactive protein (hsCRP) were measured at week 1 (baseline) and weeks 5, 9 and 14. HDRS-17 and neuropsychological function was assessed at weeks 1, 9 and 14 using a test battery including the RAVLT Auditory Verbal Learning Test (primary depression and primary cognition outcomes in the original trial). RESULTS: EPO had no cumulative effect on plasma levels of IL-6 or IL-18 but increased hsCRP levels in patients with TRD (mean±SD change in ng/L: EPO: 0.43±1.64; Saline: -0.90±2.43; F(1,39)=4.78, p=0.04). EPO had no effects on inflammatory markers in BD. There was no correlation between change in inflammatory markers and change in verbal memory. CONCLUSIONS: Repeated EPO infusions had no effect on IL-6 and IL-18 levels but produced a modest increase in hsCRP levels in patients with TRD. Changes over time in inflammatory markers were not correlated with changes in cognition suggesting that modulation of the inflammatory pathway is not a putative mechanism of the EPO-associated improvement of cognition in affective disorders.

The glucagon-like peptide 1 (GLP-1) receptor agonist exendin-4 reduces cocaine self-administration in mice.

Glucagon-like peptide 1 (GLP-1) analogues are used for the treatment of type 2 diabetes. The ability of the GLP-1 system to decrease food intake in rodents has been well described and parallels results from clinical trials. GLP-1 receptors are expressed in the brain, including within the ventral tegmental area (VTA) and the nucleus accumbens (NAc). Dopaminergic neurons in the VTA project to the NAc, and these neurons play a pivotal role in the rewarding effects of drugs of abuse. Based on the anatomical distribution of GLP-1 receptors in the brain and the well-established effects of GLP-1 on food reward, we decided to investigate the effect of the GLP-1 analogue exendin-4 on cocaine- and dopamine D1-receptor agonist-induced hyperlocomotion, on acute and chronic cocaine self-administration, on cocaine-induced striatal dopamine release in mice and on cocaine-induced c-fos activation. Here, we report that GLP-1 receptor stimulation reduces acute and chronic cocaine self-administration and attenuates cocaine-induced hyperlocomotion. In addition, we show that peripheral administration of exendin-4 reduces cocaine-induced elevation of striatal dopamine levels and striatal c-fos expression implicating central GLP-1 receptors in these responses. The present results demonstrate that the GLP-1 system modulates cocaine's effects on behavior and dopamine homeostasis, indicating that the GLP-1 receptor may be a novel target for the pharmacological treatment of drug addiction.

Elevated levels of IL-6 and IL-18 in manic and hypomanic states in rapid cycling bipolar disorder patients.

Inflammatory system dysregulation may be involved in the pathophysiology of bipolar disorder with peripheral cytokine levels varying between affective states; however, the evidence is based primarily on case-control studies and limited by methodological issues. The objectives of the present study were to assess alterations of peripheral cytokine levels between affective states in rapid cycling bipolar disorder patients and to compare these with levels in healthy control subjects. In a longitudinal design, repeated measurements of plasma levels of IL-6, IL-10, IL-18, IL-1ß and TNF-α were obtained in affective states of varying polarity during 6-12 months in 37 rapid cycling bipolar disorder patients and compared with repeated measurements in 40 age- and gender matched healthy control subjects, using rigorous laboratory-, clinical- and statistical methodology. Adjusting for demographical, clinical- and lifestyle factors, levels of IL-6 (p<0.05) and IL-18 (p<0.005) were significantly elevated in rapid cycling bipolar disorder patients in a manic/hypomanic state, compared with a depressed and a euthymic state. Compared with healthy control subjects, unadjusted levels of IL-6 (p<0.05) and IL-18 (p<0.05) were elevated in manic/hypomanic bipolar disorder patients. Levels of IL-10 and IL-1ß were undetectable in the majority of samples; high TNF-α assay variability was found. The results support a role for altered peripheral immune response signaling in rapid cycling bipolar disorder and suggest that IL-6 and IL-18 could be markers of manic episodes.

'In situ simulation' versus 'off site simulation' in obstetric emergencies and their effect on knowledge, safety attitudes, team performance, stress, and motivation: study protocol for a randomized controlled trial.

BACKGROUND: Unexpected obstetric emergencies threaten the safety of pregnant women. As emergencies are rare, they are difficult to learn. Therefore, simulation-based medical education (SBME) seems relevant. In non-systematic reviews on SBME, medical simulation has been suggested to be associated with improved learner outcomes. However, many questions on how SBME can be optimized remain unanswered. One unresolved issue is how 'in situ simulation' (ISS) versus 'off site simulation' (OSS) impact learning. ISS means simulation-based training in the actual patient care unit (in other words, the labor room and operating room). OSS means training in facilities away from the actual patient care unit, either at a simulation centre or in hospital rooms that have been set up for this purpose. METHODS AND DESIGN: The objective of this randomized trial is to study the effect of ISS versus OSS on individual learning outcome, safety attitude, motivation, stress, and team performance amongst multi-professional obstetric-anesthesia teams.The trial is a single-centre randomized superiority trial including 100 participants. The inclusion criteria were health-care professionals employed at the department of obstetrics or anesthesia at Rigshospitalet, Copenhagen, who were working on shifts and gave written informed consent. Exclusion criteria were managers with staff responsibilities, and staff who were actively taking part in preparation of the trial. The same obstetric multi-professional training was conducted in the two simulation settings. The experimental group was exposed to training in the ISS setting, and the control group in the OSS setting. The primary outcome is the individual score on a knowledge test. Exploratory outcomes are individual scores on a safety attitudes questionnaire, a stress inventory, salivary cortisol levels, an intrinsic motivation inventory, results from a questionnaire evaluating perceptions of the simulation and suggested changes needed in the organization, a team-based score on video-assessed team performance and on selected clinical performance. DISCUSSION: The perspective is to provide new knowledge on contextual effects of different simulation settings. TRIAL REGISTRATION: ClincialTrials.gov NCT01792674.

TFEB-mediated autophagy rescues midbrain dopamine neurons from α-synuclein toxicity.

The aggregation of α-synuclein plays a major role in Parkinson disease (PD) pathogenesis. Recent evidence suggests that defects in the autophagy-mediated clearance of α-synuclein contribute to the progressive loss of nigral dopamine neurons. Using an in vivo model of α-synuclein toxicity, we show that the PD-like neurodegenerative changes induced by excess cellular levels of α-synuclein in nigral dopamine neurons are closely linked to a progressive decline in markers of lysosome function, accompanied by cytoplasmic retention of transcription factor EB (TFEB), a major transcriptional regulator of the autophagy-lysosome pathway. The changes in lysosomal function, observed in the rat model as well as in human PD midbrain, were reversed by overexpression of TFEB, which afforded robust neuroprotection via the clearance of α-synuclein oligomers, and were aggravated by microRNA-128-mediated repression of TFEB in both A9 and A10 dopamine neurons. Delayed activation of TFEB function through inhibition of mammalian target of rapamycin blocked α-synuclein induced neurodegeneration and further disease progression. The results provide a mechanistic link between α-synuclein toxicity and impaired TFEB function, and highlight TFEB as a key player in the induction of α-synuclein-induced toxicity and PD pathogenesis, thus identifying TFEB as a promising target for therapies aimed at neuroprotection and disease modification in PD.

The neuronal KCNQ channel opener retigabine inhibits locomotor activity and reduces forebrain excitatory responses to the psychostimulants cocaine, methylphenidate and phencyclidine.

Many central stimulating drugs have a pronounced stimulatory effect on striatal and cortical activity which is associated to enhanced function of mesencephalic dopaminergic neurons. Mesencephalic KCNQ (also termed K(v)7) potassium channels suppress the basal activity of dopaminergic neurons in the substantia nigra and ventral tegmental area. These regions have extensive dopaminergic projections to the striatum and cortex, and positive modulation of KCNQ channel function may therefore potentially reduce the reinforcing impact of central stimulating drugs. We studied the effects of the principal neuronal KCNQ channel opener, retigabine, in rats exposed acutely to cocaine, methylphenidate (dopamine reuptake inhibitors) or phencyclidine (PCP, a psychotomimetic NMDA receptor antagonist). Retigabine (> or =1.0 mg/kg) inhibited cocaine, methylphenidate and PCP-stimulated locomotor activity. Also, retigabine reduced spontaneous locomotor activity. The inhibitory effect of retigabine on psychostimulant-induced locomotor activity was accompanied by a marked reduction in c-Fos expression, in particular the nucleus accumbens and primary motor cortex were responsive to retigabine pre-treatment. Notably, retigabine also reduced basal extracellular levels of striatal dopamine metabolites and partially prevented dopamine overflow in the striatum induced by dopamine reuptake blockade. In combination, these data suggest that retigabine reduces striatal and cortical excitability, thereby attenuating excitatory effects of central stimulating drugs in dopamine-rich areas of the rat forebrain. KCNQ channel openers may therefore be of potential relevance in the treatment of addiction states caused by abuse of psychostimulants.

The KCNQ channel opener retigabine inhibits the activity of mesencephalic dopaminergic systems of the rat.

Homo- and heteromeric complexes of KCNQ channel subunits are the molecular correlate of the M-current, a neuron-specific voltage-dependent K(+) current with a well established role in control of neural excitability. We investigated the effect of KCNQ channel modulators on the activity of dopaminergic neurons in vitro and in vivo in the rat ventral mesencephalon. The firing of dopaminergic neurons recorded in mesencephalic slices was robustly inhibited in a concentration-dependent manner by the KCNQ channel opener N-(2-amino-4-(4-fluorobenzylamino)-phenyl) carbamic acid ethyl ester (retigabine). The effect of retigabine persisted in the presence of tetrodotoxin and simultaneous blockade of GABA(A) receptors, small-conductance calcium-activated K(+) (SK) channels, and hyperpolarization-activated (I(h)) channels, and it was potently reversed by the KCNQ channel blocker 4-pyridinylmethyl-9(10H)-anthracenone (XE991), indicating a direct effect on KCNQ channels. Likewise, in vivo single unit recordings from dopaminergic neurons revealed a prominent reduction in spike activity after systemic administration of retigabine. Furthermore, retigabine inhibited dopamine synthesis and c-Fos expression in the striatum under basal conditions. Retigabine completely blocked the excitatory effect of dopamine D(2) autoreceptor antagonists. Again, the in vitro and in vivo effects of retigabine were completely reversed by preadministration of XE991. Dual immunocytochemistry revealed that KCNQ4 is the major KCNQ channel subunit expressed in all dopaminergic neurons in the mesolimbic and nigrostriatal pathways. Collectively, these observations indicate that retigabine negatively modulates dopaminergic neurotransmission, likely originating from stimulation of mesencephalic KCNQ4 channels.

Serotonin depletion results in a decrease of the neuronal activation caused by rivastigmine in the rat hippocampus.

Interactions between the serotonergic and cholinergic systems are known to occur and are believed to play a role in the mechanism underlying both major depression and Alzheimer's disease. On a molecular level, studies suggest that acetylcholine (ACh) increases serotonin (5-HT) release through nicotinic receptors located at nerve terminals. The aim of the present study was to determine in which areas and to what extent 5-HT mediates the neuronal response to ACh release. For this purpose, neuronal activity was measured in rats with rivastigmine-induced elevated ACh levels after a 95% 5-HT depletion obtained by dosing p-chlorophenylalanine followed by D,L-fenfluramine. Neuronal activation was quantified by stereological measurements of c-Fos immunoreactivity. The brain areas examined were medial prefrontal cortex, septum, dorsal hippocampus, and dorsal raphe nucleus. Rivastigmine significantly increased c-Fos immunoreactivity in medial prefrontal cortex and the hippocampus, but not in the septum and dorsal raphe nucleus. 5-HT depletion decreased ACh-induced c-Fos immunoreactivity in the dentate gyrus. By contrast, 5-HT depletion had no effect on the ACh-induced activity in the other brain areas examined. It is concluded that 5-HT mediates part of the ACh-induced hippocampal neuronal activation, possibly mediated via locally released 5-HT.