Subacute intranasal oxytocin improves neurological recovery after ischemic stroke.

Reactive attachment disorder (RAD) is associated with socially and emotionally withdrawn/inhibited behaviors and reduced neural responses to rewards. Children and adolescents with RAD show aberrant attachment behaviors, and existing psychotherapies are difficult to maintain; therefore, pharmacological interventions to aid and boost treatment responses are needed. Oxytocin (OT) administration is known to promote reward functioning. We investigated whether single-use intranasal OT administration improved neural responses during reward processing in patients with RAD compared with healthy controls. Twenty-four male children and adolescents with RAD (10-18 years old) and 27 age- and sex-matched typically developing individuals (10-17 years old) were included in this randomized, double-blind, placebo-controlled, cross-over, functional magnetic resonance imaging study. Following a single intranasal OT (24 IU) or placebo administration, neural responses were investigated using a monetary reward task. In the RAD group, OT significantly increased subjective motivation scores, significantly enhanced activation in the right middle frontal gyrus, and reduced activation in the right precentral gyrus during the monetary reward task. Additional analyses revealed increased activation in the bilateral caudate at a more lenient threshold. Under placebo conditions, the severity of internalizing problems in patients with RAD was negatively correlated with ventral striatal activity. Moreover, the effect of OT on ventral striatum activity was positively associated with the severity of internalizing problems in patients with RAD. Intranasal OT administration enhanced activity in the reward pathway in male children and adolescents with RAD, suggesting that exogenous OT promotes reward processing and reward-related motivational behavior in these individuals. Further investigation is needed to fully understand the neural mechanisms of intranasal OT and identify novel targets for pediatric cases with RAD. Clinical trial registration: UMIN-CTR; UMIN000013215. URL: https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000015419.

Boosting decision-making in rat models of early-life adversity with environmental enrichment and intranasal oxytocin

BackgroundConverging evidence demonstrates the important role of the neuropeptide hormone oxytocin (OT) in human behaviour and cognition. Intranasal OT administration has been shown to improve several aspects of social communication, such as the theory of mind performance and gaze to the eye region, and reduce anxiety and related negative cognitive appraisals. While this early research has demonstrated the potential for intranasal OT to treat psychiatric illnesses characterized by social impairments, the neurobiological mechanisms are not well known. Researchers have used functional magnetic resonance imaging (fMRI) to examine the neural correlates of OT response; however, results have been variable and moderating factors are poorly understood. The aim of this meta-analysis is to synthesize data examining the impact of intranasal OT administration on neural activity.Methods/designStudies that report fMRI data after intranasal OT administration will be identified. PubMed, Embase, PsycINFO, and Google Scholar databases will be searched as well as the citation lists of retrieved articles. Eligible articles written in English from 2005 onwards will be included in the meta-analysis, and corresponding authors of these papers will be invited to contribute t-maps. Data will be collected from eligible studies for synthesis using Seed-based d Mapping (SDM) or Multi-Level Kernel Density Analysis (MKDA), depending on the number of usable t-maps received. Additionally, publication bias and risk of bias will be assessed.DiscussionThis systematic review and meta-analysis will be the first pre-registered synthesis of data to identify the neural correlates of OT nasal spray response. The identification of brain regions underlying OT’s observed effects will help guide future research and better identify treatment targets.Systematic review registrationPROSPERO CRD42016038781Electronic supplementary materialThe online version of this article (doi:10.1186/s13643-016-0386-2) contains supplementary material, which is available to authorized users.

Effects of intranasal oxytocin in food intake and craving: A meta-analysis of clinical trials

Mild hypothermia (32-35 degrees C) has been repeatedly shown in laboratory models to reduce damage resulting from global cerebral ischemic insults. Little information is available, however, regarding the protective potential of mild hypothermia against focal ischemia. We designed the present study to determine whether mild hypothermia influences outcome from either temporary or permanent middle cerebral artery occlusion in the rat. In experiment 1 (permanent occlusion), mechanically ventilated, halothane-anesthetized spontaneously hypertensive rats underwent permanent ligation of the middle cerebral artery. Pericranial temperature was maintained at either 37 degrees C (n = 11) or 33 degrees C (n = 11) during the first 2 hours of occlusion. In experiment 2 (temporary occlusion), the vessel was occluded for 1 hour only. Pericranial temperature was controlled at either 37 degrees C (n = 12) or 33 degrees C (n = 14) during ischemia and for 1 hour after reperfusion. In both experiments, the rats were allowed to recover, with neurological function scored at 24 and 96 hours after onset of ischemia. Cerebral infarct volume (as determined by nitro blue tetrazolium staining) was planimetrically evaluated 96 hours after onset of ischemia. No difference in infarct volume was observed between groups undergoing permanent occlusion (177 +/- 53 mm3 for 37 degrees C rats, 167 +/- 71 mm3 for 33 degrees C rats [mean +/- SD]). Although neurologic function correlated with infarct volume at 96 hours (all animals in experiment 1 combined; p less than 0.01), we were unable to demonstrate an intergroup difference in function. In animals undergoing temporary occlusion, mean +/- SD infarct volume was 48% less in the hypothermic group (89 +/- 54 mm3 for 37 degrees C, 46 +/- 31 mm3 for 33 degrees C; p less than 0.03). Neurological function again correlated with infarct size (p less than 0.02), but improvement in function approached significance for the hypothermic group (p less than 0.06) at 24 hours after reperfusion only. Benefits from mild hypothermia may be obtained under conditions of temporary but not permanent middle cerebral artery occlusion in the rat.

Sensitivity to Intranasal Oxytocin in Adult Men with Early Parental Separation

Permanent middle cerebral artery occlusion (MCAO) causes neurodegeneration and a robust activation of glial cells primarily in sensorimotor brain regions of rats. It has been shown that hyperbaric oxygen (HBO) increases oxygen supply to ischaemic areas and reduces neuronal cell loss. The effects of HBO treatment on microgliosis and astrogliosis in permanent cerebral ischaemia have not been addressed so far, but might be critical for neurodegeneration and neuroprotection, respectively. Therefore, we used spontaneously hypertensive rats with permanent MCAO to investigate the time window to start HBO and to compare the effects of different HBO treatment frequencies on infarct volume and on differences with regard to microgliosis and astrogliosis. Seven days after MCAO the infarct volume was calculated from Nissl-stained brain sections by image analysis. HBO significantly decreased the infarct volume when used as early as 15, 90 or 180 min post-MCAO by 24%, 16% and 13%, respectively, in the single-treatment group. Repetitive HBO treatment (first HBO session 90 min after MCAO) was not effective. Microglial cells and astrocytes were detected by cytochemical fluorescent labelling and confocal laser scanning microscopy. In the single-treatment group we observed significantly higher astrocyte immunoreactivity but decreased microglial density in the peri-infarct region. These effects of HBO treatment on glial cells were not present in rats where HBO did not reduce the infarct volume (360 min after MCAO). Our data indicate that HBO-induced suppression of microgliosis and aggravated response of astrocytes might contribute to the reported beneficial effects of early HBO treatment in cerebral ischaemia.

Shengui Sansheng San extraction is an angiogenic switch via regulations of AKT/mTOR, ERK1/2 and Notch1 signal pathways after ischemic stroke

Ischemic stroke induces metabolic disarray. A central regulatory site, pyruvate dehydrogeanse complex (PDHC) sits at the cross-roads of 2 fundamental metabolic pathways: aerobic and anaerobic. In this study, we combined ethanol (EtOH) and normobaric oxygen (NBO) to develop a novel treatment to modulate PDHC and its regulatory proteins, namely pyruvate dehydrogenase phosphatase and pyruvate dehydrogenase kinase, leading to improved metabolism and reduced oxidative damage. Sprague-Dawley rats were subjected to transient (2, 3, or 4 hours) middle cerebral artery occlusion followed by 3- or 24-hour reperfusion, or permanent (28 hours) middle cerebral artery occlusion without reperfusion. At 2 hours after the onset of ischemia, rats received either an intraperitoneal injection of saline, 1 dose of EtOH (1.5 g/kg) for 2- and 3-hour middle cerebral artery occlusion, 2 doses of EtOH (1.5 g/kg followed by 1.0 g/kg in 2 hours) in 4 hours or permanent middle cerebral artery occlusion, and EtOH+95% NBO (at 2 hours after the onset of ischemia for 6 hours) in permanent stroke. Infarct volumes and neurological deficits were examined. Oxidative metabolism and stress were determined by measuring ADP/ATP ratio and reactive oxygen species levels. Protein levels of PDHC, pyruvate dehydrogenase kinase, and pyruvate dehydrogenase phosphatase were assessed. EtOH induced dose-dependent neuroprotection in transient ischemia. Compared to EtOH or NBO alone, NBO+EtOH produced the best outcomes in permanent ischemia. These therapies improved brain oxidative metabolism by decreasing ADP/ATP ratios and reactive oxygen species levels, in association with significantly raised levels of PDHC and pyruvate dehydrogenase phosphatase, as well as decreased pyruvate dehydrogenase kinase. Both EtOH and EtOH+NBO treatments conferred neuroprotection in severe stroke by affecting brain metabolism. The treatment may modulate the damaging cascade of metabolic events by bringing the PDHC activity back to normal metabolic levels.

Quantifying peripheral oxytocin (OT) in humans is of increased interest due to its substantial role in cognition and social behavior (e.g. depression, autism). OT is commonly measured by immunoassays, which lack the sensitivity to accurately quantitate the very low basal circulating levels in non‐pregnant/lactating humans due to matrix interferences. This can be resolved by solid phase extraction (SPE) but is inconsistently performed, leading to large variation in OT levels across studies (Leng, 2016). Liquid chromatography mass spectrometry (LCMS) can separate interferences but requires high resolution accurate‐mass (HRAM) capabilities for selective and accurate quantitation.We developed a HRAM orbitrap based LCMS method to measure underivatized native OT from serum after SPE. 0.5 mL serum with OT‐d5 as internal standard underwent C18 SPE followed by Q‐Exactive LCMS analysis with a C18 core‐shell based column (Kinetex, 150 × 3.0 mm; 2.6 μm) and a linear gradient (formic acid/MeCN). The doubly protonated OT ion m/z 562.25503 was selected for MS quantitation due its high signal intensity. Our method LLOQ was 10 pg/mL, which permitted accurate OT measurement in healthy pregnant women (n=4, 16–24 pg/mL), rats (350 pg/mL) and healthy adults after intranasal OT administration. Intra‐day precision was 2–23% and 0% while accuracy was 66~91% and 108~109% at 47.6 and 90.9 pg/mL.A method for ‘total’ OT (OT‐R/A) measuring 500–700 pg/mL in adult plasma was reported recently using LCMSMS after chemical reduction with 1,4‐dithiothreitol, which supposedly disrupted protein binding, followed by alkylation with iodoacetamide to stabilize the reduced product (Brandtzaeg, 2016). Using this method even higher levels were reported from non‐pregnant/lactating subjects (Semba, 2016, Comminos, 2017). However, the masses used for OT‐R/A analysis by Brandtzaeg were for the singly protonated molecule and differed from the theoretical masses by 39.8 ppm while the doubly protonated species used by Semba for quantitation (562.8/839.1(b6); 562.8/286.1(y3); 562.8/446.0(y4) differed by 970 pm. These measured masses were shown in our HRAM LCMS system to be interferences and not OT‐R/A. When we selected a mass window of ≤6 ppm, our HRAM system was unable to detect native OT‐R/A while OT‐R/A was detectable after spiking with OT down to 10 pg/mL plus OT‐d5‐R/A was detected each time after adding OT‐d5 as internal standard.Underivatized OT was correctly measured in monkeys by LCMSMS after SPE purification using MRM transitions 1007‐>723, 285 and 1012‐>723, 290 for the singly protonated native OT and OT‐d5, respectively with basal levels <LLOQ (10 pg/mL; Lee, 2017), which is in excellent agreement with our results. Similarly, others reported mean circulating OT levels <10 pg/mL in non‐pregnant/lactating humans using 2D‐LCMSMS (1–2 pg/mL; Zhang, 2011) with 3 of the 10 subjects <LLOQ (1 pg/mL) and ELISA after SPE (Carson, 2015; mean 6.7 pg/mL) or <2 pg/mL using RIA after SPE (van Londen, 1997; Modahl, 1998). Accurate OT methods find <10 pg/mL OT in serum/plasma of non‐pregnant/lactating/OT medicated humans.PMIDs: Brandtzaeg 27528413; Carson 25349162; Comminos 28112678; Lee 28289281; Leng 27467712; Modahl 9513736; Semba 28508553; van Londen 9326754; Zhang 21609710Support or Funding InformationnoneThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

BackgroundWe recently reported that poly-arginine peptides have neuroprotective properties both in vitro and in vivo. In cultured cortical neurons exposed to glutamic acid excitotoxicity, we demonstrated that neuroprotective potency increases with polymer length plateauing at R15 to R18 (R = arginine resides). In an in vivo study in rats, we also demonstrated that R9D (R9 peptide synthesised with D-isoform amino acids) administered intravenously at a dose of 1000 nmol/kg 30 min after permanent middle cerebral artery occlusion (MCAO) reduces infarct volume. Based on these positive in vitro and in vivo findings, we decided to examine the neuroprotective efficacy of the L-isoform poly-arginine peptides, R12, R15 and R18 when administered at a dose of 1000 nmol/kg 30 min after permanent MCAO in the rat.ResultsAt 24 h post-MCAO, there was reduced total infarct volume for R12 (12.8 % reduction) and R18 (20.5 % reduction), but this reduction only reached statistical significance for R18. Brain slice analysis revealed significantly reduced injury in coronal slices 4 and 5 for R18, and slice 5 for R12. The R15 peptide had no effect on infarct volume. Peptide treatment did not reveal any statistical significant improvement in functional outcomes.ConclusionWhile these findings confirm the in vivo neuroprotective properties of poly-arginine peptides, additional dose studies are required particularly in less severe transient MCAO models so as to further assess the potential of these agents as a stroke therapy.

Intranasal oxytocin in the treatment of anorexia nervosa: Randomized controlled trial during re-feeding

The interaction between the oxytocin and pain modulation in headache patients

Previously, we demonstrated that cerebral focal ischemic tissue exhibits a significant increase in immunoreactive endothelin (ET). Because increased ET might exacerbate the consequences of cerebral ischemia, we evaluated the effects of the orally active ETA/B receptor antagonist SB 217242 on middle cerebral artery occlusion (MCAO) in the spontaneously hypertensive rat (SHR). SHRs were treated b.i.d. with vehicle or with 3 or 15 mg/kg SB 217242 p.o. for 7 days. Permanent MCAO was performed on day 7 and animals were sacrificed on day 8. Forebrains were stained and the extent of cerebral (i.e., cortical) infarction was determined using image analysis. Hemispheric swelling (%), hemispheric infarct (%), and infarct volume (mm3) were quantitated for each animal. SB 217242 treatment produced a significant decrease in ischemic brain injury. Hemispheric infarction and infarct volume were reduced after the 15 mg/kg treatment (12.0 +/- 1.1% and 69 +/- 6 mm3) compared to vehicle (17.3 +/- 1.5% and 99 +/- 8 mm3) (p < 0.05). No significant effects on hemispheric swelling were observed. This is the first demonstration of an ET receptor antagonist exhibiting efficacy in cerebral focal ischemia. The fact that a 30% reduction in ischemic brain injury can be demonstrated after oral administration of SB 217242 suggests that ET antagonists may be of therapeutic utility in focal stroke.

Angiotensin-(1-7) [Ang-(1-7)] has anti-inflammatory effects in peripheral organs, but its effects in ischaemic stroke are unclear as yet. We investigated whether its anti-inflammatory effect contributes to the neuroprotection induced by Ang-(1-7) in a rat model of permanent middle cerebral artery occlusion (pMCAO). We infused Ang-(1-7), Mas receptor antagonist A-779, angiotensin II type 2 receptor antagonist PD123319 or artificial CSF into the right lateral ventricle of male Sprague-Dawley rats from 48 h before onset of pMCAO until the rats were killed. Twenty-four hours after pMCAO, the neuroprotective effect of Ang-(1-7) was analysed by evaluating infarct volume and neurological deficits. The levels of oxidative stress were detected by spectrophotometric assay. The activation of NF-κB was assessed by Western blot and immunohistochemistry analysis. The level of COX-2 was tested by Western blot analysis and concentrations of pro-inflammatory cytokines were measured by elisa. Infusion of Ang-(1-7), i.c.v., significantly reduced infarct volume and improved neurological deficits. It decreased the levels of oxidative stress and suppressed NF-κB activity, which was accompanied by a reduction of pro-inflammatory cytokines and COX-2 in the peri-infarct regions. These effects of Ang-(1-7) were reversed by A-779 but not by PD123319. Additionally, infusion of A-779 alone increased oxidative stress levels and enhanced NF-κB activity, which was accompanied by an up-regulation of pro-inflammatory cytokines and COX-2. Our findings indicate that suppressing NF-κB dependent pathway via Mas receptor may represent one mechanism that contributes to the anti-inflammatory effects of Ang-(1-7) in rats with pMCAO.