Hippocampal damage mediated by corticosteroids--a neuropsychiatric research challenge

Neurochemical differences in core regions of the autistic brain: a multivoxel 1H-MRS study in children

Autism spectrum disorder (ASD) is a neurodevelopmental condition which compromises various cognitive and behavioural domains. The understanding of the pathophysiology and molecular neurobiology of ASD is still an open critical research question. Here, we aimed to address ASD neurochemistry in the same time point at key regions that have been associated with its pathophysiology: the insula, hippocampus, putamen and thalamus. We conducted a multivoxel proton magnetic resonance spectroscopy (1H-MRS) study to non-invasively estimate the concentrations of total choline (GPC + PCh, tCho), total N-acetyl-aspartate (NAA + NAAG, tNAA) and Glx (Glu + Gln), presenting the results as ratios to total creatine while investigating replication for ratios to total choline as a secondary analysis. Twenty-two male children aged between 10 and 18 years diagnosed with ASD (none with intellectual disability, in spite of the expected lower IQ) and 22 age- and gender-matched typically developing (TD) controls were included. Aspartate ratios were significantly lower in the insula (tNAA/tCr: p = 0.010; tNAA/tCho: p = 0.012) and putamen (tNAA/tCr: p = 0.015) of ASD individuals in comparison with TD controls. The Glx ratios were significantly higher in the hippocampus of the ASD group (Glx/tCr: p = 0.027; Glx/tCho: p = 0.011). Differences in tNAA and Glx indices suggest that these metabolites might be neurochemical markers of region-specific atypical metabolism in ASD children, with a potential contribution for future advances in clinical monitoring and treatment.

Multidirectional associations between the gut microbiota and Parkinson's disease, updated information from the perspectives of humoral pathway, cellular immune pathway and neuronal pathway

The human gastrointestinal tract is inhabited by a diverse range of microorganisms, collectively known as the gut microbiota, which form a vast and complex ecosystem. It has been reported that the microbiota-gut-brain axis plays a crucial role in regulating host neuroprotective function. Studies have shown that patients with Parkinson's disease (PD) have dysbiosis of the gut microbiota, and experiments involving germ-free mice and fecal microbiota transplantation from PD patients have revealed the pathogenic role of the gut microbiota in PD. Interventions targeting the gut microbiota in PD, including the use of prebiotics, probiotics, and fecal microbiota transplantation, have also shown efficacy in treating PD. However, the causal relationship between the gut microbiota and Parkinson's disease remains intricate. This study reviewed the association between the microbiota-gut-brain axis and PD from the perspectives of humoral pathway, cellular immune pathway and neuronal pathway. We found that the interactions among gut microbiota and PD are very complex, which should be "multidirectional", rather than conventionally regarded "bidirectional". To realize application of the gut microbiota-related mechanisms in the clinical setting, we propose several problems which should be addressed in the future study.

Novel Psychopharmacological Herbs Relieve Behavioral Abnormalities and Hippocampal Dysfunctions in an Animal Model of Post-Traumatic Stress Disorder

Post-traumatic stress disorder (PTSD) is an anxiety disorder caused by traumatic or frightening events, with intensified anxiety, fear memories, and cognitive impairment caused by a dysfunctional hippocampus. Owing to its complex phenotype, currently prescribed treatments for PTSD are limited. This study investigated the psychopharmacological effects of novel COMBINATION herbal medicines on the hippocampus of a PTSD murine model induced by combining single prolonged stress (SPS) and foot shock (FS). We designed a novel herbal formula extract (HFE) from Chaenomeles sinensis, Glycyrrhiza uralensis, and Atractylodes macrocephala. SPS+FS mice were administered HFE (500 and 1000 mg/kg) once daily for 14 days. The effects of HFE of HFE on the hippocampus were analyzed using behavioral tests, immunostaining, Golgi staining, and Western blotting. HFE alleviated anxiety-like behavior and fear response, improved short-term memory, and restored hippocampal dysfunction, including hippocampal neurogenesis alteration and aberrant migration and hyperactivation of dentate granule cells in SPS+FS mice. HFE increased phosphorylation of the Kv4.2 potassium channel, extracellular signal-regulated kinase, and cAMP response element-binding protein, which were reduced in the hippocampus of SPS+FS mice. Therefore, our study suggests HFE as a potential therapeutic drug for PTSD by improving behavioral impairment and hippocampal dysfunction and regulating Kv4.2 potassium channel-related pathways in the hippocampus.

Brain vitamin D3-auto/paracrine system in relation to structural, neurophysiological, and behavioral disturbances associated with glucocorticoid-induced neurotoxicity

Introduction

Vitamin D3 (VD3) is a potent para/autocrine regulator and neurosteroid that can strongly influence nerve cell function and counteract the negative effects of glucocorticoid (GC) therapy. The aim of the study was to reveal the relationship between VD3 status and behavioral, structural-functional and molecular changes associated with GC-induced neurotoxicity.

Methods

Female Wistar rats received synthetic GC prednisolone (5 mg/kg b.w.) with or without VD3 (1000 IU/kg b.w.) for 30 days. Behavioral, histological, physiological, biochemical, molecular biological (RT-PCR, Western blotting) methods, and ELISA were used.

Results and discussion

There was no difference in open field test (OFT), while forced swim test (FST) showed an increase in immobility time and a decrease in active behavior in prednisolone-treated rats, indicative of depressive changes. GC increased the perikaryon area, enlarged the size of the nuclei, and caused a slight reduction of cell density in CA1-CA3 hippocampal sections. We established a GC-induced decrease in the long-term potentiation (LTP) in CA1-CA3 hippocampal synapses, the amplitude of high K+-stimulated exocytosis, and the rate of Ca2+-dependent fusion of synaptic vesicles with synaptic plasma membranes. These changes were accompanied by an increase in nitration and poly(ADP)-ribosylation of cerebral proteins, suggesting the development of oxidative-nitrosative stress. Prednisolone upregulated the expression and phosphorylation of NF-κB p65 subunit at Ser311, whereas downregulating IκB. GC loading depleted the circulating pool of 25OHD3 in serum and CSF, elevated VDR mRNA and protein levels but had an inhibitory effect on CYP24A1 and VDBP expression. Vitamin D3 supplementation had an antidepressant-like effect, decreasing the immobility time and stimulating active behavior. VD3 caused a decrease in the size of the perikaryon and nucleus in CA1 hippocampal area. We found a recovery in depolarization-induced fusion of synaptic vesicles and long-term synaptic plasticity after VD3 treatment. VD3 diminished the intensity of oxidative-nitrosative stress, and suppressed the NF-κB activation. Its ameliorative effect on GC-induced neuroanatomical and behavioral abnormalities was accompanied by the 25OHD3 repletion and partial restoration of the VD3-auto/paracrine system.

Conclusion

GC-induced neurotoxicity and behavioral disturbances are associated with increased oxidative-nitrosative stress and impairments of VD3 metabolism. Thus, VD3 can be effective in preventing structural and functional abnormalities in the brain and behavior changes caused by long-term GC administration.

Pathophysiological aspects of complex PTSD - a neurobiological account in comparison to classic posttraumatic stress disorder and borderline personality disorder

Despite a great diagnostic overlap, complex posttraumatic stress disorder (CPTSD) has been recognised by the ICD-11 as a new, discrete entity and recent empirical evidence points towards a distinction from simple posttraumatic stress disorder (PTSD) and borderline personality disorder (BPD). The development and maintenance of these disorders is sustained by neurobiological alterations and studies using functional magnetic resonance imaging (fMRI) may further contribute to a clear differentiation of CPTSD, PTSD and BPD. However, there are no existing fMRI studies directly comparing CPTSD, PTSD and BPD. In addition to a summarization of diagnostic differences and similarities, the current review aims to provide a qualitative comparison of neuroimaging findings on affective, attentional and memory processing in CPTSD, PTSD and BPD. Our narrative review alludes to an imbalance in limbic-frontal brain networks, which may be partially trans-diagnostically linked to the degree of trauma symptoms and their expression. Thus, CPTSD, PTSD and BPD may underlie a continuum where similar brain regions are involved but the direction of activation may constitute its distinct symptom expression. The neuronal alterations across these disorders may conceivably be better understood along a symptom-based continuum underlying CPTSD, PTSD and BPD. Further research is needed to amend for the heterogeneity in experimental paradigms and sample criteria.

Fermented Perilla frutescens Ameliorates Depression-like Behavior in Sleep-Deprivation-Induced Stress Model

Excessive stress plays a critical role in the pathogenesis of mood disorders such as depression. Fermented natural products have recently attracted attention because of their health benefits. We evaluated the antidepressant-like efficacy of fermented Perilla frutescens (FPF), and its underlying mechanisms, in sleep deprivation (SD)-induced stress mice. SD-stressed mice revealed a remarkable increase in the immobility time in both forced swimming test and tail suspension test; this increase was ameliorated by treatment with FPF at doses of 100 and 150 mg/kg. FPF treatment also reduced the level of stress hormones such as corticosterone and adrenocorticotropic hormone. Additionally, FPF increased the levels of serotonin and dopamine which were significantly decreased in the brain tissues of SD-stressed mice. The increased expression of proinflammatory cytokines, such as TNF-α and IL1β, and the decreased expression of brain-derived neurotrophic factor (BDNF) in the stressed mice were significantly reversed by FPF treatment. Furthermore, FPF also increased phosphorylation of tropomyosin receptor kinase B (TrkB), extracellular regulated protein kinase (ERK), and cAMP response element binding protein (CREB). Among the six components isolated from FPF, protocatechuic acid and luteolin-7-O-glucuronide exhibited significant antidepressant-like effects, suggesting that they are major active components. These findings suggest that FPF has therapeutic potential for SD-induced stress, by correcting dysfunction of hypothalamic-pituitary-adrenal axis and modulating the BDNF/TrkB/ERK/CREB signaling pathway.

Neurotensin agonist PD 149163 modulates the neuroinflammation induced by bacterial endotoxin lipopolysaccharide in mice model

OBJECTIVE

The disruption of bidirectional communication between neuroendocrine and immune components by stressors leads to mental problems. The immunomodulation therapy of neuroinflammation-led psychiatric illness is an emerging area of research. Therefore, the present study aimed to evaluate immune modulation efficacy of PD 149163 (PD) against the lipopolysaccharide (LPS)-induced neuroinflammation.

MATERIALS AND METHODS

The Swiss albino mice (female/12 weeks) were divided into six groups (6 mice/group): (I) Control: 0.9% NaCl; (II) LPS: 1 mg/kg BW, for 5 days; (III) LPS + PD Low: LPS 1 mg/kg BW (for 5 days) after that PD 100 µg/kg BW (for 21 days); (IV) LPS + PD High: LPS 1 mg/kg BW (for 5 days) after that PD 300 µg/kg BW (for 21 days); (V) PD Low: PD 100 µg/kg BW (for 21 days); (VI) PD High: PD 300 µg/kg BW (for 21 days). All treatments were given intraperitoneal.

RESULTS

The LPS-induced weight loss (body and brain) was normalized to control after PD treatment. The PD enhanced superoxide dismutase (SOD) activity while decreased lipid hydroperoxide (LOOH) level altered in LPS-exposed mice. The significantly increased pro-inflammatory cytokines (IL-6 and TNF-α) in LPS exposure were also decreased by PD. Likewise, the LPS-induced HPA axis activation was stabilized by PD. In the hippocampus, the pyramidal cell layer thickness, pyramidal neurons number and size of CA1 and CA3 regions were reduced along with misalignment, shrinkage, and impairment of cytoarchitecture. In the co-treated group, the LPS-induced hippocampus disruption was reversed after PD exposure.

CONCLUSION

We suggested that the PD modulates the LPS-induced neuroinflammation and psychiatric illness in a dose-dependent manner.

Neurosteroid-based intervention using Ganaxolone and Emapunil for improving stress-induced myelination deficits and neurobehavioural disorders

BACKGROUND

Prenatal stress is associated with long-term disturbances in white matter development and behaviour in children, such as attention deficit hyperactivity disorder (ADHD) and anxiety. Oligodendrocyte maturation and myelin formation is a tightly orchestrated process beginning during gestation, and therefore is very vulnerable to the effects of maternal prenatal stresses in mid-late pregnancy. The current study aimed to examine the effects of prenatal stress on components of the oligodendrocyte lineage to identify the key processes that are disrupted and to determine if postnatal therapies directed at ameliorating white matter deficits also improve behavioural outcomes.

METHODS

Pregnant guinea pig dams were exposed to control-handling or prenatal stress with strobe light exposure for 2hrs/day on gestational age (GA) 50, 55, 60 and 65, and allowed to spontaneously deliver ~GA70. Pups were administered oral ganaxolone (5 mg/kg/day in 45% cyclodextrin) or the TSPO agonist, emapunil (XBD173; 0.3 mg/kg/day in 1% tragacanth gum) or vehicle, on postnatal days (PND) 1-7. Behavioural outcomes were assessed using open field and elevated plus maze testing on PND7 and PND27. Hippocampal samples were collected at PND30 to assess markers of oligodendrocyte development through assessment of total oligodendrocytes (OLIG2) and mature cells (myelin basic protein; MBP), and total neurons (NeuN) by immunostaining. Real-time PCR was conducted on hippocampal regions to assess markers of the oligodendrocyte lineage, markers of neurogenesis and components of the neurosteroidogenesis pathway. Plasma samples were collected for steroid quantification of cortisol, allopregnanolone, progesterone and testosterone by ELISA.

RESULTS

Prenatal stress resulted in hyperactivity in male offspring, and anxiety-like behaviour in female offspring in the guinea pig at an age equivalent to late childhood. Postnatal ganaxolone and emapunil treatment after prenatal stress restored the behavioural phenotype to that of control in females only. The oligodendrocyte maturation lineage, translation of MBP mRNA-to-protein, and neurogenesis were disrupted in prenatally-stressed offspring, resulting in a decreased amount of mature myelin. Emapunil treatment restored mature myelin levels in both sexes, and reversed disruptions to the oligodendrocyte lineage in female offspring, an effect not seen with ganaxolone treatment.

CONCLUSION

The marked and persisting behavioural and white matter perturbations observed in a clinically relevant guinea pig model of prenatal stress highlights the need for postnatal interventions that increase myelin repair and improve long-term outcomes. The effectiveness of emapunil treatment in restoring female offspring behaviour, and promoting maturation of myelin indicates that early therapeutic interventions can reverse the damaging effects of major stressful events in pregnancy. Further studies optimising target mechanisms and dosing are warranted.

Standardized Bacopa monnieri Extract Ameliorates Learning and Memory Impairments through Synaptic Protein, Neurogranin, Pro-and Mature BDNF Signaling, and HPA Axis in Prenatally Stressed Rat Offspring

Prenatal stress (PNS) influences offspring neurodevelopment, inducing anxiety-like behavior and memory deficits. We investigated whether pretreatment of Bacopa monnieri extract (CDRI-08/BME) ameliorates PNS-induced changes in signaling molecules, and changes in the behavior of Wistar rat offspring. Pregnant rats were randomly assigned into control (CON)/prenatal stress (PNS)/PNS and exposed to BME treatment (PNS + BME). Dams were exposed to stress by placing them in a social defeat cage, where they observed social defeat from gestational day (GD)-16–18. Pregnant rats in the PNS + BME group were given BME treatment from GD-10 to their offspring’s postnatal day (PND)-23, and to their offspring from PND-15 to -30. PNS led to anxiety-like behavior; impaired memory; increased the level of corticosterone (CORT), adrenocorticotropic hormone, glucocorticoid receptor, pro-apoptotic Casepase-3, and 5-HT_2C receptor; decreased anti-apoptotic Bcl-2, synaptic proteins (synaptophysin, synaptotagmin-1), 5-HT_1A, receptor, phosphorylation of calmodulin-dependent protein kinase II/neurogranin, N-methyl-D-aspartate receptors (2A,2B), postsynaptic density protein 95; and conversion of pro and mature brain derived neurotropic factor in their offspring. The antioxidant property of BME possibly inhibiting the PNS-induced changes in observed molecules, anxiety-like behavior, and memory deficits. The observed results suggest that pretreatment of BME could be an effective coping strategy to prevent PNS-induced behavioral impairments in their offspring.

The role of the brain renin-angiotensin system (RAS) in mild traumatic brain injury (TBI)

There is considerable interest in traumatic brain injury (TBI) induced by repeated concussions suffered by athletes in sports, military personnel from combat-and non-combat related activities, and civilian populations who suffer head injuries from accidents and domestic violence. Although the renin-angiotensin system (RAS) is primarily a systemic cardiovascular regulatory system that, when dysregulated, causes hypertension and cardiovascular pathology, the brain contains a local RAS that plays a critical role in the pathophysiology of several neurodegenerative diseases. This local RAS includes receptors for angiotensin (Ang) II within the brain parenchyma, as well as on circumventricular organs outside the blood-brain-barrier. The brain RAS acts primarily via the type 1 Ang II receptor (AT₁R), exacerbating insults and pathology. With TBI, the brain RAS may contribute to permanent brain damage, especially when a second TBI occurs before the brain recovers from an initial injury. Agents are needed that minimize the extent of injury from an acute TBI, reducing TBI-mediated permanent brain damage. This review discusses how activation of the brain RAS following TBI contributes to this damage, and how drugs that counteract activation of the AT₁R including AT₁R blockers (ARBs), renin inhibitors, angiotensin-converting enzyme (ACE) inhibitors, and agonists at type 2 Ang II receptors (AT₂) and at Ang (1-7) receptors (Mas) can potentially ameliorate TBI-induced brain damage.

Psychological Stress Phenocopies Brain Mitochondrial Dysfunction and Motor Deficits as Observed in a Parkinsonian Rat Model

Psychological distress is a public health issue as it contributes to the development of human diseases including neuropathologies. Parkinson's disease (PD), a chronic, progressive neurodegenerative disorder, is caused by multiple factors including aging, mitochondrial dysfunction, and/or stressors. In PD, a substantial loss of substantia nigra (SN) neurons leads to rigid tremors, bradykinesia, and chronic fatigue. Several studies have reported that the hypothalamic-pituitary-adrenal (HPA) axis is altered in PD patients, leading to an increase level of cortisol which contributes to neurodegeneration and oxidative stress. We hypothesized that chronic psychological distress induces PD-like symptoms and promotes neurodegeneration in wild-type (WT) rats and exacerbates PD pathology in PINK1 knockout (KO) rats, a well-validated animal model of PD. We measured the bioenergetics profile (oxidative phosphorylation and glycolysis) in the brain by employing an XF24e Seahorse Extracellular Flux Analyzer in young rats subjected to predator-induced psychological distress. In addition, we analyzed anxiety-like behavior, motor function, expression of antioxidant enzymes, mitochondrial content, and neurotrophic factors brain-derived neurotrophic factor (BDNF) in the brain. Overall, we observed that psychological distress diminished up to 50% of mitochondrial respiration and glycolysis in the prefrontal cortex (PFC) derived from both WT and PINK1-KO rats. Mechanistically, the level of antioxidant proteins, mitochondrial content, and BDNF was significantly altered. Finally, psychological distress robustly induced anxiety and Parkinsonian symptoms in WT rats and accelerated certain symptoms of PD in PINK1-KO rats. For the first time, our collective data suggest that psychological distress can phenocopy several aspects of PD neuropathology, disrupt brain energy production, as well as induce ataxia-like behavior.

The complex neurobiology of resilient functioning after childhood maltreatment

BACKGROUND

Childhood maltreatment has been associated with significant impairment in social, emotional and behavioural functioning later in life. Nevertheless, some individuals who have experienced childhood maltreatment function better than expected given their circumstances.

MAIN BODY

Here, we provide an integrated understanding of the complex, interrelated mechanisms that facilitate such individual resilient functioning after childhood maltreatment. We aim to show that resilient functioning is not facilitated by any single 'resilience biomarker'. Rather, resilient functioning after childhood maltreatment is a product of complex processes and influences across multiple levels, ranging from 'bottom-up' polygenetic influences, to 'top-down' supportive social influences. We highlight the complex nature of resilient functioning and suggest how future studies could embrace a complexity theory approach and investigate multiple levels of biological organisation and their temporal dynamics in a longitudinal or prospective manner. This would involve using methods and tools that allow the characterisation of resilient functioning trajectories, attractor states and multidimensional/multilevel assessments of functioning. Such an approach necessitates large, longitudinal studies on the neurobiological mechanisms of resilient functioning after childhood maltreatment that cut across and integrate multiple levels of explanation (i.e. genetics, endocrine and immune systems, brain structure and function, cognition and environmental factors) and their temporal interconnections.

CONCLUSION

We conclude that a turn towards complexity is likely to foster collaboration and integration across fields. It is a promising avenue which may guide future studies aimed to promote resilience in those who have experienced childhood maltreatment.

Leonurine promotes neurite outgrowth and neurotrophic activity by modulating the GR/SGK1 signaling pathway in cultured PC12 cells

Depression is a common psychiatric disorder that affects almost 10% of children and adolescents worldwide. Numerous synthetic chemical antidepressants used to treat depression have adverse side effects. Therefore, new therapeutic approaches for depression treatment are urgently needed. Leonurus cardiaca has recently been shown to be effective for the treatment of nervous system diseases such as depression, but its mechanism is not clear. In this study, we aimed to reveal the mechanism underlying leonurine’s antidepressant activity. Leonurine was used to treat corticosterone-induced PC12 cells to examine its effect on neurite outgrowth and neurotrophic factors after treatment with the inhibitor of glucocorticoid receptor (GR) and serum-inducible and glucocorticoid-inducible kinase 1 (SGK1). Methyl thiazolyl tetrazolium assays were used to evaluate the viability of cells. High content analysis was used to detect cell area, total neurite length, maximum neurite length, and expression of GR, SGK1, brain-derived neurotrophic factor (BDNF), neurotrophic factor-3 (NT-3), and B-cell lymphoma-2 (BCL-2). The results showed that leonurine increased cell viability in a concentration-dependent manner, with the maximal prosurvival effect at 60 μM. Leonurine increased cell area, total neurite length, and maximum neurite length of corticosterone-induced PC12 cells, increased the expression of GR, BDNF, NT-3, and BCL-2, and decreased the expression of SGK1. After treatment with GR inhibitor RU486, the expressions of GR, BDNF, NT-3, and BCL-2 were significantly decreased and SGK1 was increased. In contrast, treatment with GSK650394 had the opposite effect of RU486. Our data indicate that leonurine promotes neurite outgrowth and neurotrophic activity in cultured PC12 cells, and its potential mechanism may involve the GR/SGK1 signaling pathway.

An anti-CRF antibody suppresses the HPA axis and reverses stress-induced phenotypes

A high-affinity monoclonal antibody (CTRND05) targeting corticotropin-releasing factor (CRF) blocks stress-induced corticosterone increases, counteracts effects of chronic variable stress, and induces other phenotypes consistent with suppression of the HPA axis.

Hypothalamic–pituitary–adrenal (HPA) axis dysfunction contributes to numerous human diseases and disorders. We developed a high-affinity monoclonal antibody, CTRND05, targeting corticotropin-releasing factor (CRF). In mice, CTRND05 blocks stress-induced corticosterone increases, counteracts effects of chronic variable stress, and induces other phenotypes consistent with suppression of the HPA axis. CTRND05 induces skeletal muscle hypertrophy and increases lean body mass, effects not previously reported with small-molecule HPA-targeting pharmacologic agents. Multiorgan transcriptomics demonstrates broad HPA axis target engagement through altering levels of known HPA-responsive transcripts such as Fkbp5 and Myostatin and reveals novel HPA-responsive pathways such as the Apelin-Apelin receptor system. These studies demonstrate the therapeutic potential of CTRND05 as a suppressor of the HPA axis and serve as an exemplar of a potentially broader approach to target neuropeptides with immunotherapies, as both pharmacologic tools and novel therapeutics.

Evaluation of the effects of chemotherapy on brain glucose metabolism in children with Hodgkin's lymphoma

OBJECTIVE

Chemobrain is a recently proposed pathological entity. ¹⁸F-FDG PET/CT can show objective abnormalities to explain brain disorders caused by chemotherapy, although no study has investigated these phenomena in children to date. The main objective of the present study was to examine quantitatively the effects of chemotherapy on brain metabolism in a homogeneous population of children treated for Hodgkin's lymphoma using 18F-FDG PET/CT.

METHODS

In this retrospective study, we included 20 children, newly diagnosed with Hodgkin's lymphoma, who underwent ¹⁸F-FDG PET/CT at initial staging and at least one PET/CT in follow-up. The SPM12 software provided t-maps to show the difference in metabolism between these PET/CTs. The statistical maps were analyzed with xjView software to identify the brain regions associated with the clusters detected.

RESULTS

Altered glucose metabolism was found in the frontal, cingular, and temporoinsular regions after two cycles of chemotherapy. Results in children were compared to a group of 35 adults. For the same statistical threshold, the extent and depth of the metabolic alterations were less in the adult group than in children.

CONCLUSIONS

¹⁸F-FDG PET/CT is useful in providing objective data to explain brain disorders caused by chemotherapy. This could lead to better care and should be compared to neuropsychological test results.

Obesity, dyslipidemia and brain age in first-episode psychosis

INTRODUCTION

Obesity and dyslipidemia may negatively affect brain health and are frequent medical comorbidities of schizophrenia and related disorders. Despite the high burden of metabolic disorders, little is known about their effects on brain structure in psychosis. We investigated, whether obesity or dyslipidemia contributed to brain alterations in first-episode psychosis (FEP).

METHODS

120 participants with FEP, who were undergoing their first psychiatric hospitalization, had <24 months of untreated psychosis and were 18-35 years old and 114 controls within the same age range participated in the study. We acquired 3T brain structural MRI, fasting lipids and body mass index. We used machine learning trained on an independent sample of 504 controls to estimate the individual brain age of study participants and calculated the BrainAGE score by subtracting the chronological from the estimated brain age.

RESULTS

In a multiple regression model, the diagnosis of FEP (B = 1.15, SE B = 0.31, p < 0.001) and obesity/overweight (B = 0.92, SE B = 0.35, p = 0.008) were each additively associated with BrainAGE scores (R² = 0.22, F(3, 230) = 21.92, p < 0.001). BrainAGE scores were highest in participants with FEP and obesity/overweight (3.83 years, 95%CI = 2.35-5.31) and lowest in normal weight controls (-0.27 years, 95%CI = -1.22-0.69). LDL-cholesterol, HDL-cholesterol or triglycerides were not associated with BrainAGE scores.

CONCLUSIONS

Overweight/obesity may be an independent risk factor for diffuse brain alterations manifesting as advanced brain age already early in the course of psychosis. These findings raise the possibility that targeting metabolic health and intervening already at the level of overweight/obesity could slow brain ageing in FEP.

Lack of CRH Affects the Behavior but Does Not Affect the Formation of Short-Term Memory

Corticotropin-releasing hormone (CRH) is involved in modification of synaptic transmission and affects spatial discrimination learning, i.e., affects the formation of memory in long-term aspect. Therefore, we have focused on CRH effect on short-term memory. We have used stress task avoidance (maze containing three zones: entrance, aversive, and neutral) and compared the behavior and short-term memory in wild-type mice and mice lacking CRH (CRH KO) experiencing one 120-min session of restraint stress. As control, non-stressed animals were used. As expected, the animals that experienced the stress situation tend to spend less time in the zone in which the restraint chamber was present. The animals spent more time in the neutral zone. There were significant differences in number of freezing bouts in the aversive and entrance zones in CRH KO animals. CRH KO control animals entered the neutral zone much more faster than WT control and spent more time immobile in the neutral zone than WT control. These data give evidence that lacking of CRH itself improves the ability of mice to escape away from potentially dangerous area (i.e., those in which the scent of stressed animal is present).

Lifetime PTSD and geriatric depression symptomatology relate to altered dorsomedial frontal and amygdala morphometry

Posttraumatic stress disorder (PTSD) affects a large portion of combat deployed Veterans. Moreover, many individuals also suffer from comorbid late life depression (geriatric depression; GD). While a great deal of research has begun to characterize the morphometric features of PTSD and depression individually, few studies have investigated the interacting effect of these two disorders, specifically in a Veteran population. The current study used cortical and subcortical surface-based morphometry (SBM) in combination with psychological assessments of PTSD and GD symptom severity to examine morphometric alterations in Vietnam War Veterans. Our results indicated that increased GD severity, PTSD symptomatology, and their interaction, was related to decreased grey matter volume (GMV) in the left dorsomedial prefrontal cortex (dmPFC). Furthermore, increased symptomatology in the PTSD subscales of reexperiencing and hyperarousal were additionally found to be related to decreased GMV in this same dmPFC region. Subcortically, the interacting effect between PTSD and GD was also significantly related to regional shape variation in the left amygdala. These results suggest that morphometry of cortical (dmPFC) and non-neocortical regions (amygdala) putatively underlying emotional reactivity and the emotional components of memory is altered in PTSD and GD.

Beta-hydroxybutyrate, an endogenic NLRP3 inflammasome inhibitor, attenuates stress-induced behavioral and inflammatory responses

Neuro-inflammation has been shown to play a critical role in the development of depression. Beta-hydroxybutyrate (BHB) is a ketone body and has recently been reported to exert anti-inflammatory effects via inhibition of NLRP3 inflammasome. Here, we investigated the potential antidepressant and anti-inflammatory effects of BHB on rats exposed to acute and chronic stress. We examined the influence of repeated BHB administration on depressive and anxiety behaviors in a rodent model of chronic unpredictable stress (CUS). Additionally, the influence of acute immobilization (IMM) stress and single BHB administration on hippocampal interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) were assessed. Repeated administration of BHB attenuated CUS-induced depressive- and anxiety-related behaviors. IMM stress increased levels of IL-1β in the hippocampus, while a single pre-administration of BHB attenuated this increase. Although no effect was observed on hippocampal TNF-α levels after 1 h of IMM stress, a single BHB pre-administration reduced hippocampal TNF-α. Our previous report showed that the release of IL-1β and TNF-α caused by stress is tightly regulated by NLRP3 inflammasome. These findings demonstrate that BHB exerts antidepressant-like effects, possibly by inhibiting NLRP3-induced neuro-inflammation in the hippocampus, and that BHB may be a novel therapeutic candidate for the treatment of stress-related mood disorders.

Posttraumatic stress disorder symptom severity is associated with left hippocampal volume reduction: a meta-analytic study

OBJECTIVE

Many studies have reported hippocampal volume reductions associated with posttraumatic stress disorder (PTSD), while others have not. Here we provide an updated meta-analysis of such reductions associated with PTSD and evaluate the association between symptom severity and hippocampal volume.

METHODS

A total of 37 studies met the criteria for inclusion in the meta-analysis. Mean effect sizes (Hedges' g) and 95% confidence intervals (CI 95%) were computed for each study and then averaged to obtain an overall mean effect size across studies. Meta-regression was employed to examine the relationship between PTSD symptom severity and hippocampal volume.

RESULTS

Results showed that PTSD is associated with significant bilateral reduction of the hippocampus (left hippocampus effect size=-0.400, p<0.001, 5.24% reduction; right hippocampus effect size=-0.462, p<0.001, 5.23% reduction). Symptom severity, as measured by the Clinician-Administered PTSD Scale (CAPS), was significantly associated with decreased left, but not right, hippocampal volume.

CONCLUSIONS

PTSD was associated with significant bilateral volume reduction of the hippocampus. Increased symptom severity was significantly associated with reduced left hippocampal volume. This finding is consistent with the hypothesis that PTSD is more neurotoxic to the left hippocampus than to the right. However, whether the association between PTSD and lower hippocampal volume reflects a consequence of or a predisposition to PTSD remains unclear. More prospective studies are needed in this area.

Neurocognitive outcomes among children who experienced seizures during treatment for acute lymphoblastic leukemia

BACKGROUND

Limited information is available regarding neurocognitive outcomes of children who experience seizures during treatment for acute lymphoblastic leukemia (ALL). Accordingly, the main objectives of this study were to determine the incidence and risk factors for treatment-related seizures among children with ALL, and the neurocognitive outcomes associated with treatment-related seizures.

PROCEDURE

Prospective neuropsychological assessment and magnetic resonance imaging (MRI) were planned for all 498 patients with newly diagnosed ALL enrolled on the St. Jude Total Therapy XV (TOTXV) protocol at three time points. The study database was reviewed retrospectively to identify those with treatment-related seizure. To assess neurocognitive changes associated with seizure, each patient with treatment-related seizure was matched with two cohort patients without seizure for age at treatment, gender, race, and treatment intensity.

RESULTS

Nineteen patients developed seizure, with a 2-year cumulative risk of 3.82 ± 0.86% (SE). No risk factors were identified to be associated with the development of seizure, with a possible exception of intensive chemotherapy used on the standard/high-risk arm as compared to the low-risk arm. Neuropsychological performance of the seizure group, as compared to normative scores and nonseizure control cohort, indicated problems in attention, working memory, and processing speed. Cognitive deficits persisted 2 years after therapy, with additional declines in intellectual function observed. MRI indicated early neurotoxicity among the seizure group, as evidenced by greater leukoencephalopathy on initial examinations.

CONCLUSION

Treatment-related seizures were associated with leukoencephalopathy and decreased neuropsychological performance. Prospective studies are needed to detect changes in neurocognitive status associated with long-term functional impairment.

Targeting psychologic stress signaling pathways in Alzheimer's disease

Alzheimer's Disease (AD) is the most prevalent progressive neurodegenerative disease; to date, no AD therapy has proven effective in delaying or preventing the disease course. In the search for novel therapeutic targets in AD, it has been shown that increased chronic psychologic stress is associated with AD risk. Subsequently, biologic pathways underlying psychologic stress have been identified and shown to be able to exacerbate AD relevant pathologies. In this review, we summarize the literature relevant to the association between psychologic stress and AD, focusing on studies investigating the effects of stress paradigms on transgenic mouse models of Amyloid-β (Aβ) and tau pathologies. In recent years, a substantial amount of research has been done investigating a key stress-response mediator, corticotropin-releasing hormone (CRH), and its interactions with AD relevant processes. We highlight attempts to target the CRH signaling pathway as a therapeutic intervention in these transgenic mouse models and discuss how targeting this pathway is a promising avenue for further investigation.

Relationship between the hippocampal shape abnormality and serum cortisol levels in first-episode and drug-naïve major depressive disorder patients

BACKGROUND

We aimed to investigate the relationship between the hippocampal shape deformations and the serum cortisol levels in first-episode and drug-naïve major depression disorder (MDD) patients.

METHODS

Thirty first-episode and drug-naïve MDD patients and 40 healthy subjects were recruited. High-resolution T1-weighted imaging and morning blood samples for cortisol measurement were obtained from all MDD patients and healthy subjects. In the hippocampal shape analysis, we compared the hippocampal shape between MDD patients and healthy subjects and evaluated the linear correlation between hippocampal shape deformations and the serum cortisol levels in MDD patients and healthy subjects.

RESULTS

MDD patients showed significant inward deformations predominantly in the cornu ammonis (CA) 1 and subiculum in bilateral hippocampi compared to healthy subjects (false discovery rate (FDR) corrected, P < .05). Furthermore, in MDD patients, a significant linear correlation between inward deformations and high cortisol levels were found predominantly in the CA1 and subiculum, extending into the CA2-3 (FDR-corrected, P < .05), whereas no significant linear correlation was observed in healthy subjects.

CONCLUSIONS

The serum cortisol levels are therefore considered to be associated with hippocampal shape abnormalities in MDD.

Control of stress-induced depressive disorders by So-ochim-tang-gamibang, a Korean herbal medicine

ETHNOPHARMACOLOGICAL RELEVANCE

So-ochim-tang-gamibang (SOCG) is a Korean herbal medicine formula that has been applied to treat depressive moods and depression associated somatoform pain. This decoction consists of Cyperus rotundus L. (Cyperi Rhizoma), Lindera aggregata (Sims) Kosterm. (Linderae Radix), Aquilaria agallochum (Lour.) Roxb. ex Finl. (Aquilariae Resinatum Lignum), Glycyrrhiza uralensis Fisch. (Glycyrrhizae Radix) Platycodon grandiflorum (Jacq.) A. DC. (Platycodi Radix), and Citrus aurantium L. (Aurantii Fructus). The aim of this study is to assess antidepressant-like effects of SOCG and to investigate its possible cellular and molecular mechanisms.

MATERIAL AND METHODS

Using chronic restraint stress animal model, effects of SOCG on depressive-like behaviors, corticosterone, and hippocampal expressions of a neurotrophic factor and an apoptotic marker, were investigated. Mice were exposed to restraint stress 6h per day over a period of two weeks, and orally administrated either SOCG (30, 100, or 300mg/kg/day). The depressive-like behaviors were analyzed by forced swimming test and open field test. The serum levels of corticosterone were measured by enzyme-linked immunosorbent assay. Expressions of caspase-3 and BDNF in the hippocampus were analyzed by immunofluorescence. Further, effects of SOCG were examined in corticosterone-treated PC12 cells. Cellular toxicity was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and lactate dehydrogenase assays. Real-time PCR was applied to investigate the cellular expression levels of Bax, Bcl-2, and BDNF. The levels of caspase-3 and BDNF were examined by Western blotting.

RESULTS

Administration of SOCG not only reduced immobility time of restraint-stressed mice in a dose-dependent manner, but also significantly increased the distance mice moved and the number of crossings in the open field test. Further, SOCG significantly reduced the serum level of corticosterone and expression of caspase-3, while increased expression of BDNF in vivo. SOCG increased cell viability in corticosterone treated PC12 cells, which was accompanied by decreased caspase-3 expression and the ratio of Bax/Bcl-2 mRNA expression as well as increased BDNF expression in vitro.

CONCLUSIONS

Taken together, our data suggested that SOCG may have potential as an antidepressant agent controlling depressive behaviors and corticosterone-induced neuronal damage caused by chronic stress.

Functional neuroanatomy associated with the interaction between emotion and cognition in explicit memory tasks in patients with generalized anxiety disorder

BACKGROUND

The functional neuroanatomy for explicit memory in conjunction with the major anxiety symptoms in patients with generalized anxiety disorder (GAD) has not yet been clearly identified.

PURPOSE

To investigate the brain activation patterns on the interaction between emotional and cognitive function during the explicit memory tasks, as well as its correlation with clinical characteristics in GAD.

MATERIAL AND METHODS

The participants comprised GAD patients and age-matched healthy controls. The fMR images were obtained while the participants performed an explicit memory task with neutral and anxiety-inducing words.

RESULTS

Patients showed significantly decreased functional activities in the putamen, head of the caudate nucleus, hippocampus, and middle cingulate gyrus during the memory tasks with the neutral and anxiety-inducing words, whereas the precentral gyrus and ventrolateral prefrontal cortex were significantly increased only in the memory tasks with the anxiety-inducing words. Also, the blood oxygenation level-dependent (BOLD) signal changes in the hippocampus were positively correlated with the recognition accuracy for both neutral and anxiety-inducing words.

CONCLUSION

This study identified the brain areas associated with the interaction between emotional regulation and cognitive function in the explicit memory tasks in patients with GAD. These findings would be helpful to understand the neural mechanism on the explicit memory-related cognitive deficits and emotional dysfunction with GAD symptoms.

Explicit verbal memory impairments associated with brain functional deficits and morphological alterations in patients with generalized anxiety disorder

BACKGROUND

Generalized anxiety disorder (GAD) is associated with brain function and morphological alterations. This study investigated explicit verbal memory impairment in patients with GAD in terms of brain functional deficits in combination with morphologic changes.

METHODS

Seventeen patients with GAD and 17 healthy controls matched for age, sex, and education level underwent high-resolution T1-weighted MRI and fMR imaging at 3 T during explicit verbal memory tasks with emotionally neutral and anxiety-inducing words.

RESULTS

In response to the neutral words, the patients showed significantly lower activities in the regions of the hippocampus (Hip), middle cingulate gyrus (MCG), putamen (Pu) and head of the caudate nucleus (HCd) compared with healthy controls. In response to the anxiety-inducing words, the patients showed significantly higher activities in the ventrolateral prefrontal cortex and precentral gyrus. However, they showed lower activities in the Hip, MCG, Pu and HCd. In addition, patients with GAD showed a significant reduction in gray matter volumes, especially in the regions of the Hip, midbrain, thalamus, insula and superior temporal gyrus, compared with healthy controls.

LIMITATIONS

This study examined a small sample sizes in each of the groups, and there was no consideration of a medication effect on brain activity and volume changes.

CONCLUSIONS

This study provides evidence for the association between brain functional deficits and morphometric alterations in an explicit verbal memory task for patients with GAD. This finding is helpful for understanding explicit verbal memory impairment in connection with GAD symptoms.

The contribution of regional gray/white matter volume in preclinical depression assessed by the Automatic Thoughts Questionnaire: a voxel-based morphometry study

Negative automatic thought is a characteristic of depression that contributes toward the risk for episodes of depression. Evidence suggests that gray and white matter abnormalities are linked with depression, but little is known about the association between the negative cognitive experience and brain structure in preclinical depression. We examined the correlation between negative thought and gray (GMV)/white matter volume (WMV) in healthy individuals with preclinical depression. The participants were 309 university students with preclinical depression, as measured by their Automatic Thoughts Questionnaire (ATQ) scores. We collected brain MRIs and used voxel-based morphometry to analyze the correlation of regional GMV/WMV with the ATQ scores. The voxel-based morphometry results showed that the GMV of the right parahippocampal gyrus and fusiform gyrus and the WMV of the right superior temporal pole increased with the severity of depression. Furthermore, the corpus callosum volume decreased with the ATQ scores. This study implied that GMV increase and corpus callosum volume reduction may be associated with negative thought in nonclinical individuals, even at a preclinical depressed level.

Common mechanisms of pain and depression: are antidepressants also analgesics?

Neither pain, nor depression exist as independent phenomena per se, they are highly subjective inner states, formed by our brain and built on the bases of our experiences, cognition and emotions. Chronic pain is associated with changes in brain physiology and anatomy. It has been suggested that the neuronal activity underlying subjective perception of chronic pain may be divergent from the activity associated with acute pain. We will discuss the possible common pathophysiological mechanism of chronic pain and depression with respect to the default mode network of the brain, neuroplasticity and the effect of antidepressants on these two pathological conditions. The default mode network of the brain has an important role in the representation of introspective mental activities and therefore can be considered as a nodal point, common for both chronic pain and depression. Neuroplasticity which involves molecular, cellular and synaptic processes modifying connectivity between neurons and neuronal circuits can also be affected by pathological states such as chronic pain or depression. We suppose that pathogenesis of depression and chronic pain shares common negative neuroplastic changes in the central nervous system (CNS). The positive impact of antidepressants would result in a reduction of these pathological cellular/molecular processes and in the amelioration of symptoms, but it may also increase survival times and quality of life of patients with chronic cancer pain.

Involvement of IGF-II receptors in the antioxidant and neuroprotective effects of IGF-II on adult cortical neuronal cultures

Insulin-like growth factor-II (IGF-II) is a naturally occurring peptide that exerts known pleiotropic effects ranging from metabolic modulation to cellular development, growth and survival. IGF-II triggers its actions by binding to and activating IGF (IGF-I and IGF-II) receptors. In this study, we assessed the neuroprotective effect of IGF-II on corticosterone-induced oxidative damage in adult cortical neuronal cultures and the role of IGF-II receptors in this effect. We provide evidence that treatment with IGF-II alleviates the glucocorticoid-induced toxicity to neuronal cultures, and this neuroprotective effect occurred due to a decrease in reactive oxygen species (ROS) production and a return of the antioxidant status to normal levels. IGF-II acts via not only the regulation of synthesis and/or activity of antioxidant enzymes, especially manganese superoxide dismutase, but also the restoration of mitochondrial cytochrome c oxidase activity and mitochondrial membrane potential. Although the antioxidant effect of IGF-I receptor activation has been widely reported, the involvement of the IGF-II receptor in these processes has not been clearly defined. The present report is the first evidence describing the involvement of IGF-II receptors in redox homeostasis. IGF-II may therefore contribute to the mechanisms of neuroprotection by acting as an antioxidant, reducing the neurodegeneration induced by oxidative insults. These results open the field to new pharmacological approaches to the treatment of diseases involving imbalanced redox homeostasis. In this study, we demonstrated that the antioxidant effect of IGF-II is at least partially mediated by IGF-II receptors.

No evidence of a longitudinal association between diurnal cortisol patterns and cognition

We examined the effect of salivary cortisol on cognitive performance and decline in 3229 adults (79% men), mean age 61 years. Six saliva samples over the day along with a cognition test battery were administered twice in 5 years. In fully-adjusted cross-sectional analyses from 2002 to 2004, higher waking cortisol was associated with higher reasoning score (β = 0.08, 95% confidence interval: 0.01, 0.15) but this finding was not replicated using data from 2007 to 2009. Over the mean 5 years follow-up there was decline in all cognitive tests but this decline did not vary as a function of cortisol levels; the exception was among APOE e4 carriers where a flatter diurnal slope and higher bedtime cortisol were associated with faster decline in verbal fluency. Changes in cortisol measures between 2002/2004 and 2007/2009 or chronically elevated levels were not associated with cognitive performance in 2007/2009. These results, based on a large sample of community-dwelling adults suggest that variability in hypothalamic-pituitary-adrenal function is not a strong contributor to cognitive aging.

Is there an association between peripheral immune markers and structural/functional neuroimaging findings?

OBJECTIVES

There is mounting evidence that inflammatory processes play a key role in emotional as well as cognitive dysfunctions. In this context, research employing magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MR spectroscopy) suggests a possible link between structural/functional anomalies in the brain and an increase of circulating inflammation markers. The present paper reviews this research, with particular focus on major depressive disorder (MDD), cognitive impairment in older adults, Alzheimer's disease (AD) and schizophrenia.

RESULTS

In MDD, cognitive impairment and AD, inflammatory processes have been found to be associated with both structural and functional anomalies, perhaps under the influence of environmental stress. Not enough research can suggest similar considerations in schizophrenia, although studies in mice and non-human primates support the belief that inflammatory responses generated during pregnancy can affect brain development and contribute to the etiology of schizophrenia.

CONCLUSIONS

The present review suggests a link between inflammatory processes and MRI detected anomalies in the brain of individuals with MDD, older adults with cognitive impairment as well as of individuals with AD and schizophrenia.

Brain Physiology and Pathophysiology in Mental Stress

Exposure to various forms of stress is a common daily occurrence in the lives of most individuals, with both positive and negative effects on brain function. The impact of stress is strongly influenced by the type and duration of the stressor. In its acute form, stress may be a necessary adaptive mechanism for survival and with only transient changes within the brain. However, severe and/or prolonged stress causes overactivation and dysregulation of the hypothalamic pituitary adrenal (HPA) axis thus inflicting detrimental changes in the brain structure and function. Therefore, chronic stress is often considered a negative modulator of the cognitive functions including the learning and memory processes. Exposure to long-lasting stress diminishes health and increases vulnerability to mental disorders. In addition, stress exacerbates functional changes associated with various brain disorders including Alzheimer’s disease and Parkinson’s disease. The primary purpose of this paper is to provide an overview for neuroscientists who are seeking a concise account of the effects of stress on learning and memory and associated signal transduction mechanisms. This review discusses chronic mental stress and its detrimental effects on various aspects of brain functions including learning and memory, synaptic plasticity, and cognition-related signaling enabled via key signal transduction molecules.

Smaller hippocampal volumes in patients with bipolar disorder are masked by exposure to lithium: a meta-analysis

BACKGROUND

Smaller hippocampal volumes relative to controls are among the most replicated neuroimaging findings in individuals with unipolar but not bipolar depression. Preserved hippocampal volumes in most studies of participants with bipolar disorder may reflect potential neuroprotective effects of lithium (Li).

METHODS

To investigate hippocampal volumes in patients with bipolar disorder while controlling for Li exposure, we performed a meta-analysis of neuroimaging studies that subdivided patients based on the presence or absence of current Li treatment. To achieve the best coverage of literature, we categorized studies based on whether all or a majority, or whether no or a minority of patients were treated with Li. Hippocampal volumes were compared by combining standardized differences between means (Cohen d) from individual studies using random-effects models.

RESULTS

Overall, we analyzed data from 101 patients with bipolar disorder in the Li group, 245 patients in the non-Li group and 456 control participants from 16 studies. Both the left and right hippocampal volumes were significantly larger in the Li group than in controls (Cohen d = 0.53, 95% confidence interval [CI] 0.18 to 0.88; Cohen d = 0.51, 95% CI 0.21 to 0.81, respectively) or the non-Li group (Cohen d = 0.93, 95% CI 0.56 to 1.31; Cohen d = 1.07, 95% CI 0.70 to 1.45, respectively), which had smaller left and right hippocampal volumes than the control group (Cohen d = -0.36, 95% CI -0.55 to -0.17; Cohen d = -0.38, 95% CI -0.63 to -0.13, respectively). There was no evidence of publication bias.

LIMITATIONS

Missing information about the illness burden or lifetime exposure to Li and polypharmacy in some studies may have contributed to statistical heterogeneity in some analyses.

CONCLUSION

When exposure to Li was minimized, patients with bipolar disorder showed smaller hippocampal volumes than controls or Li-treated patients. Our findings provide indirect support for the negative effects of bipolar disorder on hippocampal volumes and are consistent with the putative neuroprotective effects of Li. The preserved hippocampal volumes among patients with bipolar disorder in most individual studies and all previous meta-analyses may have been related to the inclusion of Li-treated participants.

Pituitary volumes are reduced in patients with somatization disorder

OBJECTIVE

Despite of the suggested physiological relationship between somatoform disorder and disturbances in HPA axis function no volumetric study of pituitary volumes in somatization disorder has been carried out. Therefore, we aimed to use structural MRI to evaluate the pituitary volumes of the patients with somatization disorder.

METHODS

Eighteen female patients with somatization disorder according to DSM-IV and same number of healthy controls were included into the study. All subjects were scanned using a 1.5-T General Electric (GE; Milwaukee, USA) scanner. Pituitary volume measurements were determined by using manuallly tracings according to standard antomical atlases.

RESULTS

It was found significantly smaller pituitary volumes of the whole group of somatization patients compared to healthy (t=-3.604, p=0.001). ANCOVA predicting pituitary volumes demonstrated a significant main effect of diagnostic group (F=13.530, p<0.001) but TBV (F=1.924, p>0.05) or age (F=1.159, p>0.05). It was determined that there was no significant correlation between smaller pituitary volumes and the duration of illness (r=0.16, p>0.05) in the patient group.

CONCLUSION

In conclusion, we suggest that the patients with somatization disorder might have significantly smaller pituitary volumes compared to healthy control subjects.

The impairment of recollection in functional amnesic states

INTRODUCTION

Functional amnesia refers to various forms of amnesia, which have no direct organic brain basis. Psychological stress and trauma were etiologically linked to its development across various cultures.

METHODS

We have studied several patients with functional amnesia, employing neuropsychological and neuroimaging methods. Herein we provide a review of the current understanding of the phenomenology, neuropsychology and neurobiology of functional amnesia, which we illustrate by reference to five own case descriptions and other cases presented in the literature.

RESULTS

Functional amnesia is mostly of retrograde nature and presents in the form of a memory blockade or repression to recollect episodic-autobiographical events, which may cover the whole past life. Sometimes, the recollection impairment is localized to certain time epochs. In comparison to functional retrograde amnesia, functional isolated anterograde amnesia is much rarer and data on its neurobiology are scant. In patients with functional amnesia with pronounced retrograde episodic-autobiographical memory impairments, we identified changes in brain metabolism, above all reductions in the temporo-frontal regions of the right hemisphere. Recently, even subtle structural changes in the white matter of the (right) frontal cortex were described in functional retrograde amnesia by other researchers.

CONCLUSIONS

The disruption in recollection in functional amnesia is often accompanied by changes in personality dimensions, pertaining to cognition (self-related processing, theory of mind), autonoetic consciousness and affectivity. This suggests that functional amnesia is a multifaceted condition. We hypothesize that the recollection deficit in functional retrograde amnesia primarily reflects a desynchronization between a frontal lobe system, important for autonoetic consciousness, and a temporo-amygdalar system, important for evaluation and emotions. Despite assumptions that functional amnesia can always be reversed, several cases of functional amnesia were found to follow a chronic course, suggesting a need for longitudinal prospective studies to quantify possible global cognitive deterioration over time and its neural underpinnings.

Hippocampal neurochemical pathology in patients with panic disorder

OBJECTIVE

In the present study, we measured hippocampal N-acetyl-l-aspartate (NAA), choline (CHO) and creatine (CRE) values in patients with panic disorder and healthy control subjects using in vivo(1)H MRS.

METHODS

We scanned 20 patients meeting Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV) criteria for panic disorder and 20 matched healthy controls with a 1.5 Tesla GE Signa Imaging System and measured of NAA, CHO, and CRE in hippocampal regions.

RESULTS

When NAA, CHO and CRE values were compared between groups, statistically significant lower levels for all ones were detected for both sides.

CONCLUSION

Consequently, in the present study we found that NAA, CHO and CRE values of the patients with panic disorder were lower than those healthy controls. Future studies involving a large number of panic patients may shed further light on the generalizability of the current findings to persons with panic disorder.

Association of amygdala volumes with cortisol secretion in unipolar depressed patients

Major depressive disorder (MDD) is accompanied by morphological changes of brain structures which are of great importance in the neural circuitry mediating depression like the hippocampus and the amygdala. Hyperactivity of the hypothalamic-pituitary-adrenocortical (HPA) system resulting in enhanced glucocorticoid secretion can often be observed during depression and has been thought to play an important role in inducing these morphological changes. We used magnetic resonance imaging to investigate alterations of amygdala and hippocampal volumes in 86 in-patients with unipolar depression and 87 healthy controls, and we then correlated amygdala and hippocampal volumes of 76 in-patients with the area under the curve of cortisol secretion in the dexamethasone/corticotropin releasing hormone (Dex/CRH) test at baseline and during short-term antidepressant therapy. In line with recently published studies both left and right amygdala volumes of patients in a first depressive episode were smaller than those of healthy controls. Patients with recurrent depressive episodes showed a reduction of hippocampal volumes, while amygdala volumes were normal. Larger left and right amygdala volumes correlated with a more pronounced reduction of HPA activity, measured by the cortisol secretion in the combined DEX/CRH test, during antidepressant therapy in patients with recurrent depressive episodes.

Hippocampal volumes in bipolar disorders: opposing effects of illness burden and lithium treatment

OBJECTIVE

Hippocampal volume decrease associated with illness burden is among the most replicated findings in unipolar depression. The absence of hippocampal volume changes in most studies of individuals with bipolar disorder (BD) may reflect neuroprotective effects of lithium (Li).

METHODS

We recruited 17 BD patients from specialized Li clinics, with at least two years of regularly monitored Li treatment (Li group), and compared them to 12 BD participants with < 3 months of lifetime Li exposure and no Li treatment within two years prior to the scanning (non-Li group) and 11 healthy controls. All BD patients had at least 10 years of illness and five episodes. We also recruited 13 Li-naïve, young BD participants (15-30 years of age) and 18 sex- and age-matched healthy controls. We compared hippocampal volumes obtained from 1.5-T magnetic resonance imaging (MRI) scans using optimized voxel-based morphometry with small volume correction.

RESULTS

The non-Li group had smaller left hippocampal volumes than controls (corrected p < 0.05), with a trend for lower volumes than the Li group (corrected p < 0.1), which did not differ from controls. Young, Li-naïve BD patients close to the typical age of onset had comparable hippocampal volumes to controls.

CONCLUSIONS

Whereas patients with limited lifetime Li exposure had significantly lower hippocampal volumes than controls, patients with comparable illness burden, but with over two years of Li treatment, or young Li-naïve BD patients, showed hippocampal volumes comparable to controls. These results provide indirect support for neuroprotective effects of Li and negative effects of illness burden on hippocampal volumes in bipolar disorders.

Reduced hippocampal volumes in healthy carriers of brain-derived neurotrophic factor Val66Met polymorphism: meta-analysis

OBJECTIVES

Converging evidence suggests that the brain-derived neurotrophic factor (BDNF) gene Val66Met polymorphism affects brain structure. Yet the majority of studies have shown no effect of this polymorphism on hippocampal volumes, perhaps due to small effect size.

METHODS

We performed a meta-analysis of studies investigating the association between Val66Met BDNF polymorphism and hippocampal volumes in healthy subjects by combining standardized differences between means (SDM) from individual studies using random effect models.

RESULTS

Data from 399 healthy subjects (255 Val-BDNF homozygotes and 144 carriers of at least one Met-BDNF allele) in seven studies were meta-analysed. Both the left and right hippocampi were significantly larger in Val-BDNF homozygotes than in carriers of at least one Met-BDNF allele (SDM = 0.41, 95% Confidence Interval = 0.20; 0.62, z = 3.86, P = 0.0001; SDM = 0.41; 95% Confidence Interval = 0.20; 0.61, z = 3.81, P = 0.0001, respectively), with no evidence of publication bias.

CONCLUSIONS

Healthy carriers of BDNF gene Val66Met polymorphism show bilateral hippocampal volume reduction. The effect size was small, but the same direction of effect was seen in all meta-analyzed studies. The association with the BDNF gene Val66Met polymorphism makes hippocampal volume a potential candidate for an endophenotype of disorders presenting with reduced hippocampal volumes.

Hippocampus and amygdalar volumes in patients with somatization disorder

In regard to somatization disorder which covers an important section of our patient population, there is no systematic structural magnetic resonance imaging (MRI) study in the literature. Therefore, we aimed to use structural MRI to evaluate the hippocampus amygdalar complex which is associated with both stress and regulation of emotion that are main basis clinical presentation of somatization disorder in the patients with somatization disorder. Totally 40 subjects (20 patients with somatization disorder and 20 healthy controls) were enrolled. Intracranial volume (ICV), whole brain volume, gray and white matter volumes, and hippocampus and amygdalar volumes of the subjects were measured. In regard to unadjusted mean volumes of measured structures, the patients had significantly smaller mean volumes of the left and right amygdala. However, two groups did not differ significantly in terms of whole brain, total gray and white matter or hippocampus volumes. The repeated measures ANCOVA predicting left and right amygdala volumes demonstrated a significant main effect of diagnostic group. In conclusion, the findings of the present study revealed that the patients with somatization disorder had significantly smaller mean volumes of the left and right amygdala without any differences in regard to whole brain, total gray and white matter or hippocampus volumes. On the basis of the current findings, it seems reasonable to evaluate that abnormalities in connectivity and/or metabolism dimensions and to examine the effects of drugs or psychotherapeutic approaches could be especially informative.

Diffusion tensor imaging of the perforant pathway zone and its relation to memory function in patients with severe traumatic brain injury

Based on the importance of the perforant pathway (PP) for normal hippocampal function, the vulnerability of temporal structures, and significant memory impairment in patients with traumatic brain injury (TBI), we investigated in vivo changes in the PP zone, hippocampus, and temporal lobe white and gray matter using diffusion tensor imaging (DTI) and volumetric analysis, and any specific relations with memory performance (Verbal Selective Reminding Test, Rey-Osterrieth Complex Figure Test), in 14 patients with severe TBI. Compared to a demographically-similar control group, our patients had significantly decreased fractional anisotropy (FA) and higher apparent diffusion coefficient (ADC) for the PP zone bilaterally, and higher ADC bilaterally in the hippocampus. Volumetric analysis revealed significantly decreased volumes in both hippocampi and temporal gray matter bilaterally. Consistent long-term retrieval (CLTR) and delayed recall were significantly related to (1) right and left PP zone ADC, (2) left hippocampus ADC, and (3) left hippocampal volume. Nonverbal memory (immediate and delayed recall) was significantly associated with (1) right and left PP zone ADC, (2) left hippocampal volume, and (3) gray (immediate recall) and white (immediate recall, bilaterally; delayed recall, left) matter temporal volumes. Advanced neuroimaging analysis can detect in vivo changes in the PP zone and temporal structures in patients with severe TBI, with these changes being highly associated with memory impairment.

Corticosterone decreases the activity of rat glutamate transporter type 3 expressed in Xenopus oocytes

Glucocorticoids can increase the extracellular concentrations of glutamate, the major excitatory neurotransmitter. We investigated the effects of corticosterone on the activity of a glutamate transporter, excitatory amino acid carrier 1 (EAAC1; also called excitatory amino acid transporter type 3 [EAAT3]), and the roles of protein kinase C (PKC) and phosphatidylinositol 3-kinase (PI3K) in regulating these effects. Rat EAAC1 was expressed in Xenopus oocytes by injecting mRNA. L-Glutamate (30 μM)-induced membrane currents were measured using the two-electrode voltage clamp technique. Exposure of these oocytes to corticosterone (0.01-1 μM) for 72 h decreased EAAC1 activity in a dose-dependent fashion, and this inhibition was incubation time-dependent. Corticosterone (0.01 μM for 72 h) significantly decreased the V(max), but not the K(m), of EAAC1 for glutamate. Furthermore, pretreatment of oocytes with staurosporine, a PKC inhibitor, significantly decreased EAAC1 activity (1.00±0.06 to 0.70±0.05 μC; P<0.05). However, no statistical differences were observed between oocytes treated with staurosporine, corticosterone, or corticosterone plus staurosporine. Similar patterns of responses were achieved by chelerythrine or calphostin C, other PKC inhibitors. Phorbol-12-myristate-13-acetate (PMA), a PKC activator, inhibited corticosterone-induced reduction in EAAC1 activity. Pretreating oocytes with wortmannin or LY294002, PI3K inhibitors, also significantly reduced EAAC1 activity, but no difference was observed between oocytes treated with wortmannin, corticosterone, or wortmannin plus corticosterone. The above results suggest that corticosterone exposure reduces EAAC1 activity and this effect is PKC- and PI3K-dependent.

Maturation of limbic regions in Asperger syndrome: a preliminary study using proton magnetic resonance spectroscopy and structural magnetic resonance imaging

People with autistic spectrum disorders (ASD, including Asperger syndrome) may have developmental abnormalities in the amygdala-hippocampal complex (AHC). However, in vivo, age-related comparisons of both volume and neuronal integrity of the AHC have not yet been carried out in people with Asperger syndrome (AS) versus controls. We compared structure and metabolic activity of the right AHC of 22 individuals with AS and 22 healthy controls aged 10-50 years and examined the effects of age between groups. We used structural magnetic resonance imaging (sMRI) to measure the volume of the AHC, and magnetic resonance spectroscopy ((1)H-MRS) to measure concentrations of N-acetyl aspartate (NAA), creatine+phosphocreatine (Cr+PCr), myo-inositol (mI) and choline (Cho). The bulk volume of the amygdala and the hippocampus did not differ significantly between groups, but there was a significant difference in the effect of age on the hippocampus in controls. Compared with controls, young (but not older) people with AS had a significantly higher AHC concentration of NAA and a significantly higher NAA/Cr ratio. People with AS, but not controls, had a significant age-related reduction in NAA and the NAA/Cr ratio. Also, in people with AS, but not controls, there was a significant relationship between concentrations of choline and age so that choline concentrations reduced with age. We therefore suggest that people with AS have significant differences in neuronal and lipid membrane integrity and maturation of the AHC.