Cytokines and cognition--the case for a head-to-toe inflammatory paradigm

Blood levels of interleukin-1 beta, interleukin-6 and tumor necrosis factor-alpha and cognitive functions in patients with obsessive compulsive disorder

BACKGROUND

Cognitive dysfunction and immune system disorders are two actual issues for the patients with Obsessive Compulsive Disorder (OCD). The cognitive dysfunctions have been considered to substantial part of clinical phenomenon of OCD but exploration of various etiopathogenesis of cognitive dysfunction is needed. Immune dysfuncion has been implicated to be important part of pathopysiology of OCD and different lines of evidence suggests immune abnormalities in OCD. But whether these immune changes are traits of disease or secondary to clinical burden of the disease such as cognitive dysfunctions has not been determined. Data regarding relation between the cognitive dysfunctions and immune system disorders in OCD is unsatisfied. In this study we aimed to investigate the relation of blood levels of interleukin 1-beta (IL-1ß), interleukin-6 (IL-6) and Tumor Necrosis Factor-α (TNF-α) with various neurocognitive functions in patients with OCD in comparison with its autogenous/reactive subtypes and healthy controls. Further exploration of the effects of various clinical variables on cognitive functioning in patients with OCD and additional investigation of whether the cognitive dysfunction associated with this disorder differs from or overlap with that in other anxiety disorders are needed.

METHODS

Forty-two patient with OCD and 45 age, sex and educational level matched healthy control were enrolled in the study. The diagnosis of OCD was made with Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). Yale- Brown Obsessive-Compulsive Scale, Beck Anxiety and Depression Inventory Scales were administered. Neuropsychological test battery including Wisconsin Card Sorting Test (WCST), Trail Making Test A and B (TMT-A, TMT-B) were used for evaluation of the patients and healthy control. The plasma of interleukin-1beta (IL-1ß), interleukin-6 (IL-6), Tumor Necrosis Factor-Alpha (TNF-α) of both groups were measured with ELISA kits.

RESULTS

Blood levels of IL-1ß, IL-6 and TNF-α were significantly higher in patients with OCD than the healthy control. There was significant difference in IL-1ß, IL-6 but not in TNF-α between autogenous/reactive subtypes and healthy controls. TNF-α is positively correlated with TMT-A, TMT-B and Stroop Test Part 5, negatively correlated with immediate memory, verbal learning, interference effect, immediate recall, delayed recall and recognition in RAVLT. IL-1ß was positively correlated with TMT-A score. IL-6 was positively correlated with scores of TMT-A, TMT-B. IL-6 was negatively correlated with immediate memory, verbal learning, interference effect, immediate recall and delayed recall in RAVLT, positively correlated with number of perseverative error and negatively correlated with the number of categories completed in WCST.

CONCLUSION

This is the first study that investigates the relation of IL- 1ß, IL-6 and TNF-α levels with cognitive functions in OCD. There may be a contribution to pathogenesis of OCD and subtypes then new choices for treatment might be developed. Moreover, uncovering the effect of cytokine blood levels on cognitive function of OCD, new data concerning etiopathogenesis and further treatment choices can be gained.

Memory deficits in males and females long after subchronic immune challenge

Memory impairments and cognitive decline persist long after recovery from major illness or injury, and correlate with increased risk of later dementia. Here we developed a subchronic peripheral immune challenge model to examine delayed and persistent memory impairments in females and in males. We show that intermittent injections of either lipopolysaccharides or Poly I:C cause memory decline in both sexes that are evident eight weeks after the immune challenge. Importantly, we observed sex-specific patterns of deficits. Females showed impairments in object recognition one week after challenge that persisted for at least eight weeks. In contrast, males had intact memory one week after the immune challenge but exhibited broad impairments in memory tasks including object recognition, and both context and tone fear conditioning several months later. The differential patterns of memory deficits in males and in females were observed without sustained microglial activation or changes in blood-brain barrier permeability. Together, these data suggest that transient neuroimmune activity results in differential vulnerabilities of females and males to memory decline after immune challenge. This model will be an important tool for determining the mechanisms in both sexes that contribute to memory impairments that develop over the weeks and months after recovery from illness. Future studies using this model will provide new insights into the role of chronic inflammation in the pathogenesis of long-lasting memory decline and dementias.

Increased brain age in adults with Prader-Willi syndrome

Prader-Willi syndrome (PWS) is the most common genetic obesity syndrome, with associated learning difficulties, neuroendocrine deficits, and behavioural and psychiatric problems. As the life expectancy of individuals with PWS increases, there is concern that alterations in brain structure associated with the syndrome, as a direct result of absent expression of PWS genes, and its metabolic complications and hormonal deficits, might cause early onset of physiological and brain aging. In this study, a machine learning approach was used to predict brain age based on grey matter (GM) and white matter (WM) maps derived from structural neuroimaging data using T1-weighted magnetic resonance imaging (MRI) scans. Brain-predicted age difference (brain-PAD) scores, calculated as the difference between chronological age and brain-predicted age, are designed to reflect deviations from healthy brain aging, with higher brain-PAD scores indicating premature aging. Two separate adult cohorts underwent brain-predicted age calculation. The main cohort consisted of adults with PWS (n = 20; age mean 23.1 years, range 19.8-27.7; 70.0% male; body mass index (BMI) mean 30.1 kg/m2, 21.5-47.7; n = 19 paternal chromosome 15q11-13 deletion) and age- and sex-matched controls (n = 40; age 22.9 years, 19.6-29.0; 65.0% male; BMI 24.1 kg/m2, 19.2-34.2) adults (BMI PWS vs. control P = .002). Brain-PAD was significantly greater in PWS than controls (effect size mean ± SEM +7.24 ± 2.20 years [95% CI 2.83, 11.63], P = .002). Brain-PAD remained significantly greater in PWS than controls when restricting analysis to a sub-cohort matched for BMI consisting of n = 15 with PWS with BMI range 21.5-33.7 kg/m2, and n = 29 controls with BMI 21.7-34.2 kg/m2 (effect size +5.51 ± 2.56 years [95% CI 3.44, 10.38], P = .037). In the PWS group, brain-PAD scores were not associated with intelligence quotient (IQ), use of hormonal and psychotropic medications, nor severity of repetitive or disruptive behaviours. A 24.5 year old man (BMI 36.9 kg/m2) with PWS from a SNORD116 microdeletion also had increased brain PAD of 12.87 years, compared to 0.84 ± 6.52 years in a second control adult cohort (n = 95; age mean 34.0 years, range 19.9-55.5; 38.9% male; BMI 28.7 kg/m2, 19.1-43.1). This increase in brain-PAD in adults with PWS indicates abnormal brain structure that may reflect premature brain aging or abnormal brain development. The similar finding in a rare patient with a SNORD116 microdeletion implicates a potential causative role for this PWS region gene cluster in the structural brain abnormalities associated primarily with the syndrome and/or its complications. Further longitudinal neuroimaging studies are needed to clarify the natural history of this increase in brain age in PWS, its relationship with obesity, and whether similar findings are seen in those with PWS from maternal uniparental disomy.

Clinical and experimental aspects of breathing modulation by inflammation

Neuroinflammation is produced by local or systemic alterations and mediated mainly by glia, affecting the activity of various neural circuits including those involved in breathing rhythm generation and control. Several pathological conditions, such as sudden infant death syndrome, obstructive sleep apnea and asthma exert an inflammatory influence on breathing-related circuits. Consequently breathing (both resting and ventilatory responses to physiological challenges), is affected; e.g., responses to hypoxia and hypercapnia are compromised. Moreover, inflammation can induce long-lasting changes in breathing and affect adaptive plasticity; e.g., hypoxic acclimatization or long-term facilitation. Mediators of the influences of inflammation on breathing are most likely proinflammatory molecules such as cytokines and prostaglandins. The focus of this review is to summarize the available information concerning the modulation of the breathing function by inflammation and the cellular and molecular aspects of this process. I will consider: 1) some clinical and experimental conditions in which inflammation influences breathing; 2) the variety of experimental approaches used to understand this inflammatory modulation; 3) the likely cellular and molecular mechanisms.

Chemotherapy and the pediatric brain

Survival rates of children with cancer are steadily increasing. This urges our attention to neurocognitive and psychiatric outcomes, as these can markedly influence the quality of life of these children. Neurobehavioral morbidity in childhood cancer survivors affects diverse aspects of cognitive function, which can include attention, memory, processing speed, intellect, academic achievement, and emotional health. Reasons for neurobehavioral morbidity are multiple with one major contributor being chemotherapy-induced central nervous system (CNS) toxicity. Clinical studies investigating the effects of chemotherapy on the CNS in children with cancer have reported causative associations with the development of leukoencephalopathies as well as smaller regional grey and white matter volumes, which have been found to correlate with neurocognitive deficits.Preclinical work has provided compelling evidence that chemotherapy drugs are potent neuro- and gliotoxins in vitro and in vivo and can cause brain injury via excitotoxic and apoptotic mechanisms. Furthermore, chemotherapy triggers DNA (deoxyribonucleic acid) damage directly or through increased oxidative stress. It can shorten telomeres and accelerate cell aging, cause cytokine deregulation, inhibit hippocampal neurogenesis, and reduce brain vascularization and blood flow. These mechanisms, when allowed to operate on the developing brain of a child, have high potential to not only cause brain injury, but also alter crucial developmental events, such as myelination, synaptogenesis, neurogenesis, cortical thinning, and formation of neuronal networks.This short review summarizes key publications describing neurotoxicity of chemotherapy in pediatric cancers and potential underlying pathomechanisms.

The association between body mass index and postpartum depression: A population-based study

BACKGROUND

Postpartum depression (PPD) reportedly affects between 6.5-19% of all new mothers. Identifying those at greatest risk for PPD has implications for prevention, early detection and intervention. While the relationship between extremes of body mass index (BMI) and depression has been frequently studied, the association between BMI and PPD is less understood.

METHODS

Prospective cohort of all women with live singleton births in Sweden 1997-2008. We calculated the relative risk (RR) for PPD in relation to each woman's BMI and depression history. PPD diagnosis was based on a clinical diagnosis of depression within the first postpartum year.

RESULTS

First trimester BMI measurements were available for 611,506 women. Low BMI (< 18.5) RR_adj = 1.52, [95% CI: 1.30-1.78] and high BMI (> 35) RR_adj = 1.23, [95% CI: 1.04-1.45] were associated with increased PPD risk. Women with a depression history had an increased risk with low BMI (RR_adj = 1.51, [95% CI: 1.17-1.95]).

LIMITATIONS

Only first births were analyzed, potentially underestimating PPD incidence. Clinical data from health registries offers limited resolution regarding the specificity of diagnoses and incomplete sensitivity if women do not seek care.

CONCLUSIONS

First trimester of pregnancy BMI is associated with PPD risk. This risk is further modified by depression history. While low BMI places all women at risk for PPD, being overweight increases risk of PPD only in women without a history of depression. Future research should explore potentially modifiable mechanisms involved in the relationship between PPD and BMI and should also examine interventional strategies for pregnant women at the extremes of BMI and/or with a depression history.

Psychological co-morbidities in COPD: Targeting systemic inflammation, a benefit for both?

COPD is a chronic lung disease characterized by persistent respiratory symptoms and airflow limitation due to airway and/or alveolar abnormalities. Furthermore, COPD is often characterized by extrapulmonary manifestations and comorbidities worsening COPD progression and quality of life. A neglected comorbidity in COPD management is mental health impairment defined by anxiety, depression and cognitive problems. This paper summarizes the evidence for impaired mental health in COPD and focuses on current pharmacological intervention strategies. In addition, possible mechanisms in impaired mental health in COPD are discussed with a central role for inflammation. Many comorbidities are associated with multi-organ-associated systemic inflammation in COPD. Considering the accumulative evidence for a major role of systemic inflammation in the development of neurological disorders, it can be hypothesized that COPD-associated systemic inflammation also affects the function of the brain and is an interesting therapeutic target for nutra- and pharmaceuticals.

Attention to Emotional Information Is Associated With Cytokine Responses to Psychological Stress

This study aimed to investigate the impact of mental stress on salivary cytokines and attention to emotional stimuli, as well as associations between stress-induced changes of immune and cognitive parameters. In a randomized order a total of 60 young adults were assigned to one of two stress conditions with varying stress intensity. High stress was induced by a socially evaluated Paced Auditory Serial Addition Test (PASAT). As a low stress task a paper-and-pencil version of PASAT was administered. Salivary cytokines were measured before, 5 min after, and 45 min after completion of the stress task, and were assayed for pro- and anti-inflammatory cytokines. Three distinct types of attention – alerting, orienting, and executive control – were measured by the modified Emotional Attention Network Test Integration (E-ANTI). IL-1β and IL-6 increased only in the high-stress group. Significant increases in IFN-α, IFN-γ, TNF-α, and IL-10 at 45 min after stress induction (all p’s < 0.05) were observed in both the high-stress and the low-stress group. Alerting attention was positively related to more pronounced increases in IFN-α and TNF-α in both groups. Further, better orienting attention after presentation of negative cues was associated with higher increases in IFN-α, TNF-α, IL-2, IL-5, and IL-10 in both groups, and higher overall levels of IFN-α, IFN-γ, and IL-12p70 in the high-stress group. There were no systematic gender differences in cytokine responses. We conclude that attention processes modulate the increases of salivary cytokines after stress exposure, and that these effects depend on stress level, particular attention network, and stimulus valence.

Role of inflammation in epilepsy and neurobehavioral comorbidities: Implication for therapy

Epilepsy is a devastating condition affecting around 70 million people worldwide. Moreover, the quality of life of people with epilepsy (PWE) is worsened by a series of comorbidities. The neurobehavioral comorbidities discussed herein share a reciprocal and complex relationship with epilepsy, which ultimately complicates the treatment process in PWE. Understanding the mechanistic pathway by which these comorbidities are associated with epilepsy might be instrumental in developing therapeutic interventions. Inflammatory cytokine signaling in the brain regulates important brain functions including neurotransmitter metabolism, neuroendocrine function, synaptic plasticity, dopaminergic transmission, the kynurenine pathway, and affects neurogenesis as well as the neural circuitry of moods. In this review, we hypothesize that the complex relationship between epilepsy and its related comorbidities (cognitive impairment, depression, anxiety, autism, and schizophrenia) can be unraveled through the inflammatory mechanism that plays a prominent role in all these individual conditions. An ample amount of evidence is available reporting the role of inflammation in epilepsy and all individual comorbid condition but their complex relationship with epilepsy has not yet been explored through the prospective of inflammatory pathway. Our review suggests that epilepsy and its neurobehavioral comorbidities are associated with elevated levels of several key inflammatory markers. This review also sheds light on the mechanistic association between epilepsy and its neurobehavioral comorbidities. Moreover, we analyzed several anti-inflammatory therapies available for epilepsy and its neurobehavioral comorbidities. We suggest, these anti-inflammatory therapies might be a possible intervention and could be a promising strategy for preventing epileptogenesis and its related neurobehavioral comorbidities.

Association of Cerebrospinal Fluid Biomarkers of Central Nervous System Injury With Neurocognitive and Brain Imaging Outcomes in Children Receiving Chemotherapy for Acute Lymphoblastic Leukemia

Importance

Little is known about treatment-related neurotoxic mechanisms in children with acute lymphoblastic leukemia (ALL) treated with chemotherapy only.

Objective

To examine concentration of cerebrospinal fluid (CSF) biomarkers of brain injury at ALL diagnosis and during cancer therapy and to evaluate associations with long-term neurocognitive and neuroimaging outcomes and relevant genetic polymorphisms.

Design, Setting, and Participants

This prospective cohort study included 235 patients with ALL who received a chemotherapy-only protocol. Patients provided CSF samples after diagnosis and throughout treatment. At 5 or more years after the diagnosis, 138 (69.7%) of 198 eligible survivors participated in long-term follow-up assessments. Children were treated from June 1, 2000, through October 31, 2010. Follow-up was completed on October 21, 2014, and data were analyzed from August 1, 2015, through September 30, 2016.

Exposures

Plasma concentration of high-dose intravenous methotrexate sodium and number of triple intrathecal chemotherapy injections.

Main Outcomes and Measures

The CSF samples were assayed at 5 points from diagnosis to reinduction for biomarkers of myelin degradation (myelin basic protein [MBP]), neuronal damage (nerve growth factor [NGF] and total and phosphorylated tau protein), astrogliosis (glial fibrillary acidic protein [GFAP]), and neuroinflammation (chitotriosidase). DNA was genotyped for polymorphisms in drug metabolism, oxidative stress, and neurodevelopment. Leukoencephalopathy was evaluated by brain imaging. At 5 or more years after the diagnosis, survivors completed neurocognitive testing and brain imaging of white matter integrity.

Results

Among the 235 patients with CSF samples (120 boys [51.1%] and 115 girls [48.9%]; mean [SD] age at diagnosis, 6.8 [4.7] years), MBP and GFAP levels were elevated at baseline and through consolidation. The number of intrathecal injections was positively correlated with NGF level increase at consolidation (r = 0.19; P = .005). Increases in GFAP (risk ratio [RR], 1.23; 95% CI, 1.09-1.40), MBP (RR, 1.06; 95% CI, 1.01-1.11), and total tau (RR, 1.76; 95% CI, 1.11-2.78) levels were associated with a higher risk for leukoencephalopathy and higher apparent diffusion coefficient in frontal lobe white matter 5 years after diagnosis (standardized estimate, 0.05; P < .001). Increase in total tau at consolidation was associated with worse attention (omissions z score estimate, -0.20; P = .04).

Conclusions and Relevance

Glial injury may be present at diagnosis of ALL. Neuronal injury was associated with intrathecal chemotherapy. The CSF biomarkers may be useful in identifying individuals at risk for worse neurologic outcomes, particularly those with genetic susceptibility to poor brain function.

Immune system and obsessive-compulsive disorder

BACKGROUND

Recently, much attention has been devoted to the possible alterations of the immune system in obsessive-compulsive disorder (OCD). Therefore, the aim of this paper was to review the current literature on the relationships between OCD and immune system.

METHODS

A PubMed and Google Scholar search was performed with specific keywords.

RESULTS

In the childhood, much emphasis has been given to the relationship between group A Streptococcus (GAS) infection and the development of a group of clinical syndromes characterized by neuropsychiatric symptoms known as "pediatric autoimmune neuropsychiatric disorders associated with streptococcus" (PANDAS). However, more recently, PANDAS has been reconsidered and evolved towards pediatric acute-onset neuropsychiatric syndrome (PANS) and/or Childhood Acute Neuropsychiatric Syndrome (CANS) all characterized by the presence of typical of OCD symptoms and tics. In adult OCD patients, different immunological parameters have been described to differ from those of healthy control subjects, although a few numbers of studies were carred out and most of them performed in small samples.

CONCLUSIONS

Although the exact relationships between OCD and immune processes are still unclear, available literature supports their role in the pathophysiology of OCD, while providing a fascinating hint for possible immunotherapeutic treatments in OCD.

Anesthetic Immunomodulation of the Neuroinflammation in Postoperative Cognitive Dysfunction

Postoperative delirium and cognitive dysfunction are phenomena that are associated with increases in morbidity, mortality, and resource utilization after surgery. This review scrutinized a number of studies in order to better characterize the biochemical basis for associated cognitive dysfunction and delirium, with particular focus paid to the interactions of the cholinergic system with innate immunity and how the modulation of the immune system contributes to associated neuroinflammation. Despite the clinical impact of postoperative cognitive dysfunction, evidence-based protocols for the prevention and treatment of these disorders are still lacking. Several previous trials have attempted to prevent or treat clinical manifestation by modulation of the cholinergic system with acetylcholinesterase inhibitors, the results of which have been largely ambiguous at best. As the biochemical basis of postoperative cognitive dysfunction becomes more clearly defined, future research into therapeutics based on immune modulation and treatment of neuroinflammation may prove to be very promising.

The role of inflammation in the development of epilepsy

Epilepsy, a neurological disease characterized by recurrent seizures, is often associated with a history of previous lesions in the nervous system. Impaired regulation of the activation and resolution of inflammatory cells and molecules in the injured neuronal tissue is a critical factor to the development of epilepsy. However, it is still unclear as to how that unbalanced regulation of inflammation contributes to epilepsy. Therefore, one of the goals in epilepsy research is to identify and elucidate the interconnected inflammatory pathways in systemic and neurological disorders that may further develop epilepsy progression. In this paper, inflammatory molecules, in neurological and systemic disorders (rheumatoid arthritis, Crohn’s, Type I Diabetes, etc.) that could contribute to epilepsy development, are reviewed.

Understanding the neurobiology of inflammation in epileptogenesis will contribute to the development of new biomarkers for better screening of patients at risk for epilepsy and new therapeutic targets for both prophylaxis and treatment of epilepsy.

Raspberry differentially improves age-related declines in psychomotor function dependent on baseline motor ability

Among older adults, falls are a leading cause of distress, pain, injury, loss of confidence, and ultimately, loss of independence and death. Previous studies in our laboratory have demonstrated that berry supplementation improves the age-related declines in balance, muscle strength, and coordination that often lead to falls, even when initiated later in life. The purpose of this study was to explore the interaction between baseline motor performance and the daily intake of raspberry required to improve/preserve motor function. Aged male F344 (17 mo) rats were tested for baseline (pre-test) balance, muscle strength, and coordination, and divided into good, average, and poor performers based on their motor composite score. Rats in each category were fed with either a control, 1%, or 2% raspberry-supplemented diet for 8 weeks and then retested (post-test). Poor performers fed with 1% or 2% raspberry had higher post-test composite scores (p < 0.05), while 2% raspberry lowered post-test composite scores in the good performers (p < 0.05), compared to control-fed rats. 1% and 2% raspberry appeared to preserve the performance of good performers and improve the performance of poor performers on plank walking (p < 0.05), while 2% raspberry improved post-test grip strength of the poor performers (p < 0.05). Additionally, rats with lower post-diet composite scores had higher levels of serum IL-1β levels (r = -0.347, p < 0.05). These findings identified poor performers as being the most likely to benefit from daily consumption of ½-2 cups of raspberry to improve/preserve motor function. Therefore, increased raspberry consumption may reduce fall risk, extend independence, and improve quality of life in the aging population.

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.

Intrinsic Functional Hypoconnectivity in Core Neurocognitive Networks Suggests Central Nervous System Pathology in Patients with Myalgic Encephalomyelitis: A Pilot Study

Exact low resolution electromagnetic tomography (eLORETA) was recorded from nineteen EEG channels in nine patients with myalgic encephalomyelitis (ME) and 9 healthy controls to assess current source density and functional connectivity, a physiological measure of similarity between pairs of distributed regions of interest, between groups. Current source density and functional connectivity were measured using eLORETA software. We found significantly decreased eLORETA source analysis oscillations in the occipital, parietal, posterior cingulate, and posterior temporal lobes in Alpha and Alpha-2. For connectivity analysis, we assessed functional connectivity within Menon triple network model of neuropathology. We found support for all three networks of the triple network model, namely the central executive network (CEN), salience network (SN), and the default mode network (DMN) indicating hypo-connectivity in the Delta, Alpha, and Alpha-2 frequency bands in patients with ME compared to controls. In addition to the current source density resting state dysfunction in the occipital, parietal, posterior temporal and posterior cingulate, the disrupted connectivity of the CEN, SN, and DMN appears to be involved in cognitive impairment for patients with ME. This research suggests that disruptions in these regions and networks could be a neurobiological feature of the disorder, representing underlying neural dysfunction.

How Does Exercise Reduce the Rate of Age-Associated Cognitive Decline? A Review of Potential Mechanisms

The rate of age-associated cognitive decline varies considerably between individuals. It is important, both on a societal and individual level, to investigate factors that underlie these differences in order to identify those which might realistically slow cognitive decline. Physical activity is one such factor with substantial support in the literature. Regular exercise can positively influence cognitive ability, reduce the rate of cognitive aging, and even reduce the risk of Alzheimer's disease (AD) and other dementias. However, while there is substantial evidence in the extant literature for the effect of exercise on cognition, the processes that mediate this relationship are less clear. This review examines cardiovascular health, production of brain derived neurotrophic factor (BDNF), insulin sensitivity, stress, and inflammation as potential pathways, via which exercise may maintain or improve cognitive functioning, and may be particularly pertinent in the context of the aging brain. A greater understanding of these mechanisms and their potential relationships with exercise and cognition will be invaluable in providing biomarkers for investigating the efficacy of differing exercise regimes on cognitive outcomes.

FOXO protects against age-progressive axonal degeneration

Neurodegeneration resulting in cognitive and motor impairment is an inevitable consequence of aging. Little is known about the genetic regulation of this process despite its overriding importance in normal aging. Here, we identify the Forkhead Box O (FOXO) transcription factor 1, 3, and 4 isoforms as a guardian of neuronal integrity by inhibiting age-progressive axonal degeneration in mammals. FOXO expression progressively increased in aging human and mouse brains. The nervous system-specific deletion of Foxo transcription factors in mice accelerates aging-related axonal tract degeneration, which is followed by motor dysfunction. This accelerated neurodegeneration is accompanied by levels of white matter astrogliosis and microgliosis in middle-aged Foxo knockout mice that are typically only observed in very old wild-type mice and other aged mammals, including humans. Mechanistically, axonal degeneration in nerve-specific Foxo knockout mice is associated with elevated mTORC1 activity and accompanying proteotoxic stress due to decreased Sestrin3 expression. Inhibition of mTORC1 by rapamycin treatment mimics FOXO action and prevented axonal degeneration in Foxo knockout mice with accelerated nervous system aging. Defining this central role for FOXO in neuroprotection during mammalian aging offers an invaluable window into the aging process itself.

Associations between inflammatory markers and cognitive function in breast cancer patients receiving chemotherapy

BACKGROUND

Cancer-related cognitive impairment (CRCI) is often related to chemotherapy. Increased chronic inflammation is believed to play a key role in the development of CRCI related to chemotherapy but studies assessing this hypothesis specifically in patients receiving chemotherapy are rare.

METHODS

We assessed several cognitive domains using the Cambridge Neuropsychological Test Automated Battery (CANTAB) in twenty-two breast cancer patients currently receiving chemotherapy. We also measured inflammatory cytokine and receptor (MCP-1, TNF-α, sTNFRI, sTNFRII) concentrations in patient sera using Luminex assays. These concentrations were log-transformed to obtain a normal distribution. Associations between log-transformed cytokines and cognition were evaluated using Pearson correlations and linear regression, taking into account relevant covariates.

RESULTS

Increased concentrations of sTNFRI and sTNFRII were associated with poorer performance on the CANTAB Delayed Matching to Sample (DMS, tests visual memory). Increasing sTNFRI levels were negatively correlated with DMS percent correct (r=-0.47, p=0.029) and DMS percent correct after a 12 second (s) delay (r=-0.65, p=0.001). Increasing levels of sTNFRII negatively correlated with DMS percent correct after 12s delay (r=-0.57, p=0.006). After controlling for relevant demographic (i.e. age, education) and clinical variables (i.e. disease stage, regimen type), we found that increased sTNFRI remained significantly related to decline on the DMS at the 12s delay (p=0.018).

CONCLUSION

This preliminary study shows a significant association between higher sTNFRI and lower scores on the short-term visual memory delayed match to sample test in breast cancer patients receiving chemotherapy, supporting the hypothesis that sTNFRI is involved in CRCI.

Stress-Induced Alterations of Immune Profile in Animals Suffering by Tau Protein-Driven Neurodegeneration

Alzheimer's disease (AD) is a multifactorial disorder; neurofibrillary pathology composed of tau protein is found side by side with amyloid-β deposits and extensive neuroinflammation. The immune system of the brain is considered as one of the factors that could influence the speed of the progression of AD neuropathology as a potential mediator of the damage induced by AD protein deposits. Alzheimer's disease pathology can be impacted by psychological stress; however, signalling pathways in background are not well known. We have explored possible avenues of how stress could influence the brain's immune system in a rat model of AD. Animals were subjected either to a single or multiple instances of immobilization stress. The analysis of a panel of immunity-related genes was used to evaluate the impact of stress on the immune response in the brain. We have identified 19 stress-responsive genes that are involved in neuroinflammation accompanying tau pathology: Nos2, Ptgs2, IL-8rb, C5, Mmp9, Cx3cr1, CD40lg, Adrb2, IL-6, IL-6r, IL-1r2, Ccl2, Ccl3, Ccl4, Ccl12, TNF-α, IL-1α, IL-1β, IL-10. Most of them are deregulated under the stress conditions also in control animals; however, the magnitude of the response to either acute or chronic stress differs. This can lead to serious influence, most probably to acceleration of neurodegenerative phenotype in diseased animals. Several of the genes (IL-1β, Casp1, Cx3cr1 and C5) are deregulated solely in tauopathic animals. The stress-induced changes in the inflammatory picture of the brain highlight the fact that the brain's immune response is highly responsive to environmental stimuli. The pattern of changes is indicative of an attempt to protect the brain in the short term, while being potentially detrimental to the response against a long-term pathological process such as neurofibrillary degeneration.

Dysregulation of C-X-C motif ligand 10 during aging and association with cognitive performance

Chronic low-grade inflammation during aging (inflammaging) is associated with cognitive decline and neurodegeneration; however, the mechanisms underlying inflammaging are unclear. We studied a population (n = 361) of healthy young and old adults from the MyoAge cohort. Peripheral levels of C-X-C motif chemokine ligand 10 (CXCL10) was found to be higher in older adults, compared with young, and negatively associated with working memory performance. This coincided with an age-related reduction in blood DNA methylation at specific CpGs within the CXCL10 gene promoter. In vitro analysis supported the role of DNA methylation in regulating CXCL10 transcription. A polymorphism (rs56061981) that altered methylation at one of these CpG sites further associated with working memory performance in 2 independent aging cohorts. Studying prefrontal cortex samples, we found higher CXCL10 protein levels in those with Alzheimer's disease, compared with aged controls. These findings support the association of peripheral inflammation, as demonstrated by CXCL10, in aging and cognitive decline. We reveal age-related epigenetic and genetic factors which contribute to the dysregulation of CXCL10.

Toxicity of inhaled agents after prolonged administration

Inhaled anesthetics have been utilized mostly for general anesthesia in the operating room and oftentimes for sedation and for treatment of refractory status epilepticus and status asthmaticus in the intensive care unit. These contexts in the ICU setting are related to potential for prolonged administration wherein potential organ toxicity is a concern. Over the last decade, several clinical and animal studies of neurotoxicity attributable to inhaled anesthetics have been emerging, particularly in extremes of age. This review overviews potential for and potential mechanisms of neurotoxicity and systemic toxicity of prolonged inhaled anesthesia and clinical scenarios where inhaled anesthesia has been used in order to assess safety of possible prolonged use for sedation. High dose inhaled agents are associated with postoperative cognitive dysfunction (POCD) and other situations. However, thus far no strong indication of problematic neuro or organ toxicity has been demonstrated after prolonged use of low dose volatile anesthesia.

Additive Role of a Potentially Reversible Cognitive Frailty Model and Inflammatory State on the Risk of Disability: The Italian Longitudinal Study on Aging

OBJECTIVE

Cognitive frailty is a condition recently defined by operationalized criteria describing the simultaneous presence of physical frailty and mild cognitive impairment (MCI). Two subtypes for this clinical construct have been proposed: "potentially reversible" cognitive frailty (physical frailty plus MCI) and "reversible" cognitive frailty (physical frailty plus pre-MCI subjective cognitive decline). Here the prevalence of a potentially reversible cognitive frailty model was estimated. It was also evaluated if introducing a diagnosis of MCI in older subjects with physical frailty could have an additive role on the risk of dementia, disability, and all-cause mortality in comparison with frailty state or MCI condition alone, with analyses separately performed for inflammatory state.

METHODS

In 2,373 individuals from the population-based Italian Longitudinal Study on Aging with a 3.5-year-follow-up, we operationally categorized older individuals without dementia into four groups: non-frail/non-MCI, non-frail/MCI, frail/non-MCI, and frail/MCI.

RESULTS

The prevalence of potentially reversible cognitive frailty was 1%, increasing with age and more represented in women than in men, and all groups were associated with significant increased incident rate ratios of dementia, disability, and mortality. A significant difference in rates of disability has been found between the MCI and non-MCI groups (contrasts of adjusted predictions: 0.461; 95% confidence interval: 0.187-0.735) in frail individuals with high inflammatory states (fibrinogen >339 mg/dL).

CONCLUSION

In older individuals without dementia and with elevated inflammation, a potentially reversible cognitive frailty model could have a significant additional predictive effect on the risk of disability than the single conditions of frailty or MCI.

Hippocampal-dependent memory deficit induced by perinatal exposure to polutted eels in middle-aged offspring mice: Sex differential effects

The effects of perinatal exposure to low, intermediate, or highly polluted eels on neonatal, postnatal, adult and middle-aged brain inflammation, and on cognitive performances of middle-aged offspring mice were compared to those of offspring controls. Inflammatory markers in microglia were assessed in offspring on the postnatal days-PNDs 1, 21, 100 and 330. Activated p38MAPK, ERK-1/2 and p65, and acetylcholine levels were assessed in the middle-aged hippocampus. Plasma myeloperoxidase and corticosterone levels were evaluated at PND 330. Learning and its retention, and working memory in middle-aged offspring were assessed using the Morris water maze, and Y-maze. Our results showed enhanced microglia production of inflammatory markers across the lifespan of male as well as female exposed offspring. Inflammation and increased p38 MAPK activation were detected in the exposed middle-aged hippocampus of both exposed sexes. Significant levels of MPO, but not corticosterone, were found in middle-aged males and females perinatally exposed to eels. However, decreases in ERK1/2 and p65 activation, and acetylcholine levels were only detected in female hippocampus exposed to either intermediately or highly polluted eels. Sex selective effects were also detected with regard to memory, the only altered cognitive function. Thus, middle-aged females, but not males, perinatally exposed to either intermediately or highly polluted eels take longer to locate the escape platform, spend considerably less time in the platform and perform less visit to the platform in the retention test. Our results suggest perinatal programming of hippocampal-dependent memory deficit by inflammation in middle-aged offspring, in sex and dose dependent manner.

Association of anti-inflammatory cytokine IL10 polymorphisms with motoric cognitive risk syndrome in an Ashkenazi Jewish population

Motoric cognitive risk (MCR) syndrome is a newly described predementia syndrome characterized by the presence of cognitive complaints and slow gait, which is associated with increased risk of conversion to dementia. The underlying biological mechanisms for MCR have not yet been established. Neuroinflammation mediated through cytokines plays a pivotal role in the pathogenesis of dementia. Hence, our objective was to prospectively examine whether variations in cytokine genes (CRP, IFNG, IL1A, IL1B, IL4, IL6, IL10, IL18, TNF, and IL12A) play a role in MCR incidence in 530 community-dwelling Ashkenazi Jewish adults aged 65 years and older without MCR or dementia at baseline enrolled in the LonGenity study. Over a median follow-up of 2.99 years, 70 participants developed MCR. Single nucleotide polymorphisms (SNPs) in the transcriptional regulatory regions of cytokine IL10, rs1800896 (hazard ratio adjusted for age, gender, and education, aHR: 1.667; 95% CI: 1.198-2.321) and rs3024498 (aHR: 1.926; 95% CI: 1.315-2.822), were associated with incident MCR. Functional analysis using in silico approaches indicated associated SNP rs3024498 "C" allele being the local expression quantitative trait locus. Associated alleles of both the SNPs, rs1800896 and rs3024498, were implicated with overexpression of IL10 gene. None of the variants in the neuroinflammatory pathway studied were associated with incident mild cognitive impairment syndrome. These observations support a role for the IL10 gene in dementia pathogenesis by increasing risk of developing MCR in older adults.

Neurologic Manifestations of Hepatitis C Virus Infection

The extrahepatic manifestations of hepatitis C include effects on the central nervous system, which have been associated with the ability of hepatitis C virus (HCV) to replicate in microglial and endothelial cells and the chronic inflammation induced by HCV. HCV can induce impaired neurocognition, which is clinically manifested by impaired quality of life, fatigue, and brain fog. These cognitive defects can be present even in patients with mild histologic HCV and have been confirmed by neurocognitive testing and brain imaging by magnetic resonance spectroscopy. Neurocognitive defects include loss of functioning memory and subtle changes in attention and processing speed.

Perinatal programming of depressive-like behavior by inflammation in adult offspring mice whose mothers were fed polluted eels: Gender selective effects

Several lines of evidence indicate that early-life inflammation may predispose to mental illness, including depression, in later-life. We investigated the impact of perinatal exposure to polluted eels on neonatal, postnatal, and adult brain inflammation, and on the resignation behavior of male and female adult offspring mice. The effects of maternal standard diet (laboratory food) were compared to the same diet enriched with low, intermediate, or highly polluted eels. Brain inflammatory markers including cytokines were assessed in offspring mice on the day of birth (i.e., on the postnatal day-PND 1), upon weaning (PND 21) and at adulthood (PND 100). Plasma myeloperoxidase and corticosterone levels were evaluated at PND 100. Immobility behavior of offspring was assessed in adulthood (i.e., at PNDs 95-100), using the tail suspension and forced swimming tests. Chronic brain inflammation was found in male and female offspring mice compared to controls, as assessed at PNDs 1, 21, and 100. The level of myeloperoxidase was found to be significantly higher in both adult males and females vs. control offspring. However, high corticosterone levels were only found in male offspring mice that were perinatally exposed to eels, suggesting a gender-selective dysregulation of the adult hypothalamic-pituitaryadrenal (HPA) axis. Gender-specific differences were also detected in adulthood in regard to offspring resignation behavior. Thus, compared to controls, males, but not females, whose mothers were fed eels during pregnancy and lactation exhibited a depressive-like behavior in adult age in both behavioral models of depression. Depressive symptoms were more pronounced in male mice perinatally exposed to either intermediate or highly polluted eels than those exposed to only lowly polluted eels. Our results indicate that early-life inflammatory insult is a plausible causative factor that induces the depressive phenotype exhibited by male adult offspring mice, most likely through a gender-specific HPA axis enhanced activation.

Dose-dependent effects of intravenous methoxamine infusion during hip-joint replacement surgery on postoperative cognitive dysfunction and blood TNF-α level in elderly patients: a randomized controlled trial

Background

Postoperative cognitive dysfunction (POCD), common in elderly patients, is thought to be closely associated with intraoperative instability of hemodynamics and excessive excretion of tumor necrosis factor-α (TNF-α). Methoxamine is a blood-pressure increasing drug commonly used for maintaining intraoperative hemodynamics. Methoxamine potentially promotes TNF-α expression, leading to an increased risk of POCD. This study aimed to investigate the dose-dependent effect of methoxamine on the incidence of early POCD and blood TNF-α level.

Methods

This single-center prospective double-blind controlled clinical trial included a total of 300 adult patients (75–90 years old, American Society of Anesthesiologists class II–III) who underwent unilateral hip-joint replacement surgery under epidural anesthesia. Patients were randomly divided into three methoxamine groups (M1, M2, and M3), and one control group (n = 75 per group). During surgery, M1, M2, and M3 patients received intravenous infusion of methoxamine at 2, 3, or 4 μg·kg⁻¹·min⁻¹, respectively; the control group received saline of same volume at the same infusion rate. All patients received standard transfusion to maintain stable circulation. Hemodynamics, cardiovascular events, and serum TNF-α levels were monitored. Mini Mental State Examination was performed both before and after surgery to diagnose POCD.

Results

The primary outcome of this study was the incidence of POCD, which was higher in the M3 group (18.7%) than in the control group (5.3%), the M1 group (6.7%), or the M2 group (6.7%) (all P < 0.05). The secondary outcomes were the postoperative blood TNF-α level and intraoperative hemodynamic parameters. The postoperative TNF-α level was found to be higher than baseline in all groups and was highest in M3 patients (P < 0.05). The intraoperative hemodynamic parameters showed improved stability in the M1 and M2 groups compared with the control group. However, in the M3 group, abnormally increased intraoperative blood pressure, cardiac output, and systolic stroke volume were observed.

Conclusions

Intravenous infusion of methoxamine at 2–3 μg·kg⁻¹·min⁻¹ can maintain stable hemodynamics in elderly patients during epidural anesthesia for hip-joint replacement surgery, without increasing the incidence of POCD. Increasing the dose to 4 μg·kg⁻¹·min⁻¹ provided no further advantages but induced adverse effects on the intraoperative hemodynamics.

Trial registration

Chinese Clinical Trial Register (Unique identifier: ChiCTR-INR-15007607, retrospectively registered 18 Dec 2015).

Cognitive Frailty: Mechanisms, Tools to Measure, Prevention and Controversy

Physical frailty is often associated with cognitive impairment, possibly because of common underlying pathophysiologic mechanisms. To stimulate research in this field, the concept cognitive frailty was proposed, emphasizing the important role of brain aging. Cognitive frailty was defined as the presence of cognitive deficits in physically frail older persons without dementia. This subtype of frailty is deemed important, as it may represent a prodromal phase for neurodegenerative diseases and is potentially a suitable target for early intervention. The aim of this report is to refine the framework for the definition and mechanisms of cognitive frailty and relevant screening tools.

Role of Pro-Inflammatory Cytokines and Vitamin D in Probable Alzheimer's Disease with Depression

Symptoms of depression are present in a significant proportion of Alzheimer's disease (AD) patients. While epidemiological studies have shown a strong association between depression and AD, it has not been established whether depression is a risk factor or merely a co-morbidity of AD. It is also uncertain if depression affects the pathogenesis of AD. In this paper, we address these questions by measuring the serum levels of two common metabolic risk factors of AD and depression, inflammatory cytokines (IL 6 and TNF alpha) and serum 25-hydroxyvitamin D, in a case-control study. We measured the serum levels of IL 6, TNF α and 25-hydroxyvitamin D in age-matched healthy controls (n= 60) and in AD patients without depression (n=26) or AD patients with depression (n=34), and statistically analyzed the changes in these parameters among different groups under this study. Our results show that in AD there is a significant increase in IL 6 and TNF α and a marked decrease in 25-hydroxyvitamin D in the peripheral circulation compared to age-matched healthy controls. Furthermore, AD patients with depression have even significantly higher levels of IL 6 or TNF α and a lower level of 25-hydroxyvitamin D in circulation than in AD patients without depression. We also found a strong statistical correlation between the disease severity and the serum levels of IL 6, TNF α and 25-hydroxyvitamin D in AD patients with depression. These results suggest that altered circulating levels of common metabolic risk factors lead to the co-existence of depression with AD in many patients, and when they co-exist, the depression presumably affects the severity of AD presentations through more aggravated changes in these risk factors.

Associations between systemic pro-inflammatory markers, cognitive function and cognitive complaints in a population-based sample of working adults

BACKGROUND

The knowledge is limited regarding the relation between systemic inflammatory biomarkers and subjective and objective cognitive functioning in population-based samples of healthy adults across the adult age-span. Thus, the aim of this study was to study a selection of four pro-inflammatory biomarkers (IL-6, MCP-1, TNF-α, CRP) in relation to executive cognitive functioning, episodic memory and subjective cognitive complaints (SCC) in a population-based sample of 215 working adults (age 25-67).

RESULTS

Higher levels of MCP-1 were associated with poorer executive cognitive functioning, even after adjustments for demographical factors, health status/conditions, SCC and depressive symptoms. IL-6 and CRP were associated with poorer executive cognitive functioning, but these associations covaried with age especially and were not present after adjustment for demographical factors. MCP-1 was associated with poorer episodic memory, but this association also covaried with age especially and was not present after adjustment for demographical factors, and CRP was associated with episodic memory only among participants without reported health conditions. Higher MCP-1 levels were also associated with more SCC and this association covaried with depressive symptoms, while higher levels of TNF-α were associated with less SCC.

CONCLUSION

Low grade inflammatory processes in terms of higher systemic levels of pro-inflammatory biomarkers (MCP-1, IL-6 & CRP) were associated with poorer executive functioning in this sample of working adults, and MCP-1 was so after extensive adjustments. Support for associations between these biomarkers and episodic memory and SCC were more limited. Future research should address the causality of associations between low grade inflammatory processes and cognitive functioning.

The effects of two-stage carotid occlusion on spatial memory and pro-inflammatory markers in the hippocampus of rats

The purpose of this study was to evaluate the effects of cerebral hypoperfusion on cognitive ability, TNFα, IL1β and PGE2 levels in both hippocampi in a modified two-vessel occlusion model. Both common carotid arteries of adult male Wistar rats were permanently occluded with an interval of 1 week between occlusions. Learning and memory were significantly decreased after 1 month. This reduction was not significant after 2 months, which may be attributed to blood flow compensation. The TNFα level was significantly increased after 3 h and 1 day. IL1β was significantly increased after 1 day. After a week there was no significant difference in pro-inflammatory levels. Furthermore, there was no difference between right and left hippocampi. It is possible that TNFα and IL1β elevation initiates pathologic processes that contribute to memory impairment.

Cognitive effects of adjunctive N-acetyl cysteine in psychosis

BACKGROUND

Cognitive deficits are predictors of functional outcome in patients with psychosis. While conventional antipsychotics are relatively effective on positive symptoms, their impact on negative and cognitive symptoms is limited. Recent studies have established a link between oxidative stress and neurocognitive deficits in psychosis. N-acetylcysteine (NAC), a glutathione precursor with glutamatergic properties, has shown efficacy on negative symptoms and functioning in patients with schizophrenia and bipolar disorder, respectively. However, there are few evidence-based approaches for managing cognitive impairment in psychosis. The present study aims to examine the cognitive effects of adjunctive NAC treatment in a pooled subgroup of participants with psychosis who completed neuropsychological assessment in two trials of both schizophrenia and bipolar disorder.

METHOD

A sample of 58 participants were randomized in a double fashion to receive 2 g/day of NAC (n = 27) or placebo (n = 31) for 24 weeks. Attention, working memory and executive function domains were assessed. Differences between cognitive performance at baseline and end point were examined using Wilcoxon's test. The Mann-Whitney test was used to examine the differences between the NAC and placebo groups at the end point.

RESULTS

Participants treated with NAC had significantly higher working memory performance at week 24 compared with placebo (U = 98.5, p = 0.027).

CONCLUSIONS

NAC may have an impact on cognitive performance in psychosis, as a significant improvement in working memory was observed in the NAC-treated group compared with placebo; however, these preliminary data require replication. Glutamatergic compounds such as NAC may constitute a step towards the development of useful therapies for cognitive impairment in psychosis.

Contribution of neuroinflammation and immunity to brain aging and the mitigating effects of physical and cognitive interventions

It is widely accepted that the brain and the immune system continuously interact during normal as well as pathological functioning. Human aging is commonly accompanied by low-grade inflammation in both the immune and central nervous systems, thought to contribute to many age-related diseases. This review of the current literature focuses first on the normal neuroimmune interactions occurring in the brain, which promote learning, memory and neuroplasticity. Further, we discuss the protective and dynamic role of barriers to neuroimmune interactions, which have become clearer with the recent discovery of the meningeal lymphatic system. Next, we consider age-related changes of the immune system and possible deleterious influences of immunosenescence and low-grade inflammation (inflammaging) on neurodegenerative processes in the normally aging brain. We survey the major immunomodulators and neuroregulators in the aging brain and their highly tuned dynamic and reciprocal interactions. Finally, we consider our current understanding of how physical activity, as well as a combination of physical and cognitive interventions, may mediate anti-inflammatory effects and thus positively impact brain aging.

Mechanisms of microglial activation in models of inflammation and hypoxia: Implications for chronic intermittent hypoxia

Chronic intermittent hypoxia (CIH) is a hallmark of sleep apnoea, a condition associated with diverse clinical disorders. CIH and sleep apnoea are characterized by increased reactive oxygen species formation, peripheral and CNS inflammation, neuronal death and neurocognitive deficits. Few studies have examined the role of microglia, the resident CNS immune cells, in models of CIH. Thus, little is known concerning their direct contributions to neuropathology or the cellular mechanisms regulating their activities during or following pathological CIH. In this review, we identify gaps in knowledge regarding CIH-induced microglial activation, and propose mechanisms based on data from related models of hypoxia and/or hypoxia-reoxygenation. CIH may directly affect microglia, or may have indirect effects via the periphery or other CNS cells. Peripheral inflammation may indirectly activate microglia via entry of pro-inflammatory molecules into the CNS, and/or activation of vagal afferents that trigger CNS inflammation. CIH-induced release of damage-associated molecular patterns from injured CNS cells may also activate microglia via interactions with pattern recognition receptors expressed on microglia. For example, Toll-like receptors activate mitogen-activated protein kinase/transcription factor pathways required for microglial inflammatory gene expression. Although epigenetic effects from CIH have not yet been studied in microglia, potential epigenetic mechanisms in microglial regulation are discussed, including microRNAs, histone modifications and DNA methylation. Epigenetic effects can occur during CIH, or long after it has ended. A better understanding of CIH effects on microglial activities may be important to reverse CIH-induced neuropathology in patients with sleep disordered breathing.

Reduced inattention and hyperactivity and improved cognition after marine oil extract (PCSO-524®) supplementation in children and adolescents with clinical and subclinical symptoms of attention-deficit hyperactivity disorder (ADHD): a randomised, double-blind, placebo-controlled trial

INTRODUCTION

This study investigated the effects of a marine oil extract (PCSO-524®) on inattention, hyperactivity, mood and cognition in children and adolescents. PCSO-524® is a standardised lipid extract of the New Zealand green-lipped mussel and is an inflammatory modulator that inhibits the 5'-lipoxygenase and cyclooxygenase pathways and decreases concentrations of the pro-inflammatory arachidonic acid (AA).

METHODS

PCSO-524® or a matched placebo was administered for 14 weeks to 144 participants (123 males/21 females; mean age 8.7 years) with high hyperactivity and inattention in a randomised, double-blind, placebo-controlled study. The primary outcome was the Conners Parent Rating Scale assessing parental reports of behavioural problems. Secondary outcomes assessed changes in cognition and mood.

RESULTS

The results of the present study did not support the hypothesis that PCSO-524® improves parental reports of hyperactivity, inattention and impulsivity in children ages 6 to 14 years over placebo. Repeated measures ANOVA on post hoc subsample analysis indicated significant improvements in hyperactivity (p = 0.04), attention (p = 0.02), learning (p = 0.05) and probability of ADHD (p = 0.04) with a medium to large average effect size (d = 0.65) in those children who did not meet criteria for combined hyperactivity and inattention. Furthermore, significant improvements in the PCSO-524® group were indicated in a whole sample repeated measures ANCOVA on recognition memory between baseline and week 8 over placebo (p = 0.02, d = 0.56); this difference was not sustained at week 14.

CONCLUSIONS

The results presented indicate that PCSO-524® may be beneficial in reducing levels of hyperactivity and inattention in a population of children with clinical and subclinical symptoms of ADHD.

Relationship of systemic cytokine concentrations to cognitive function over two years in women with early stage breast cancer

Cancer and its treatment are frequently associated with cancer-related cognitive impairment (CRCI). While CRCI has been associated with linked to chemotherapy, there is increasing evidence that the condition may start prior to treatment and for some, remain unresolved after active treatment and into survivorship. Although the pathophysiology of the condition is complex, alterations in systemic cytokines, signaling molecules activated in response to infection or injury that trigger inflammation, are a possible mechanism linked to cognitive dysfunction in breast cancer and other conditions. Given the conflicting results in the literature, the lack of focus on domain specific cognitive testing, and the need for a longer time period given the multiple modalities of standard treatments for early-stage breast cancer, this longitudinal study was conducted to address these gaps.

METHODS

We assessed 75 women with early-stage breast cancer at five points over two years, starting prior to the initial chemotherapy through 24months after chemotherapy initiation. Measures included a validated computerized evaluation of domain-specific cognitive functioning and a 17-plex panel of plasma cytokines. Linear mixed-effects models were applied to test the relationships of clinical variables and cytokine concentrations to each cognitive domain.

RESULTS

Levels and patterns of cytokine concentrations varied over time: six of the 17 cytokines (IL-6, IL-12, IL-17, G-CSF, MIPS-1β, and MCP-1) had the most variability. Some cytokine levels (e.g., IL-6) increased during chemotherapy but then decreased subsequently, while others (e.g., IL-17) consistently declined from baseline over time. There were multiple relationships among cytokines and cognition, which varied over time. At baseline, elevated concentrations of G-CSF and reduced concentrations of IL-17 were associated with faster psychomotor speed. At the second time-point (prior to the mid-chemotherapy), multiple cytokines had significant associations with psychomotor speed, complex attention, executive function, verbal memory, cognitive flexibility, composite memory and visual memory. Six months after chemotherapy initiation and at the one-year point, there were multiple, significant relationships among cytokines and multiple cognitive. At two years, fewer significant relationships were noted; however, lower concentrations of IL-7, a hematopoietic cytokine, were associated with better psychomotor speed, complex attention, and memory (composite, verbal and visual). MCP-1 was inversely associated with psychomotor speed and complex attention and higher levels of MIP-1β were related to better complex attention.

CONCLUSION

Levels and patterns of cytokines changed over time and demonstrated associations with domain-specific cognitive functioning that varied over time. The observed associations between cytokines and cognitive performance provides evidence that not only prototypical cytokines (i.e., IL-6, TNF-α, and IL1-β) but also cytokines from multiple classes may contribute to the inflammatory environment that is associated with cognitive dysfunction. Future studies to better delineate the cytokine changes, both individually and in networks, are needed to precisely assess a mechanistic link between cytokines and cognitive function in women receiving treatments for breast cancer.

Attenuation of stress induced memory deficits by nonsteroidal anti-inflammatory drugs (NSAIDs) in rats: Role of antioxidant enzymes

BACKGROUND

Repeated stress paradigms have been shown to cause devastating alterations on memory functions. Stress is linked with inflammation. Psychological and certain physical stressors could lead to neuroinflammation. Inflammatory process may occur by release of mediators and stimulate the production of prostaglandins through cyclooxygenase (COX). Treatment with COX inhibitors, which restrain prostaglandin production, has enhanced memory in a number of neuroinflammatory states showing a potential function for raised prostaglandins in these memory shortfalls. In the present study, potential therapeutic effects of indomethacin and diclofenac sodium on memory in both unrestraint and restraint rats were observed.

METHODS AND RESULTS

Two components, long term memory and short term memory were examined by Morris water maze (MWM) and elevated plus maze (EPM) respectively. The present study also demonstrated the effect of nonsteroidal anti-inflammatory drugs (NSAIDs) on lipid peroxidation (LPO) and activities of antioxidant enzymes along with the activity of acetylcholinesterase (AChE). Results of MWM and EPM showed significant effects of drugs in both unrestraint and restraint rats as escape latency and transfer latency, in respective behavioral models were decreased as compared to that of control. This study also showed NSAIDs administration decreased LPO and increased antioxidant enzymes activity and decreased AChE activity in rats exposed to repeated stress.

CONCLUSION

In conclusion this study suggests a therapeutic potential of indomethacin and diclofenac against repeated stress-induced memory deficits.

Health Outcomes Associated with Self-Reported Vision Impairment in Older Adults

Introduction

To compare the health status of older adults with and without vision impairment, this study employed a disability framework consisting of four stages, progressing from risk factors; through pathology and impairments that result in declining functioning; and eventually to disability.

Methods

Data from five rounds (1999 to 2008) of the National Health and Nutrition Examination Study were analyzed. Binary and multinomial logistic regression were used to estimate odds ratios, with 95% confidence intervals reflecting the likelihood of negative health outcomes among persons with self-reported fair and poor vision relative to persons with good vision.

Results

Fair and poor vision status were associated with negative health outcomes across the four health dimensions.

Discussion

Disparities in health among vision status groups may originate as a result of limitations in daily activities that could lead to changes in diet, health maintenance, and activity levels. Alternatively, disparities may reflect primary pathologies and conditions that are secondarily related to poor vision status. Longitudinal research is suggested in order to assess the order of key events, and to make a more powerful assertion of causality.

Implications for practitioners

Comparisons of health outcomes by vision status are important because of the potential to identify points in the disability framework where effective interventions could prevent progression to later stages in the disability process.

Obesity associated with increased brain age from midlife

Common mechanisms in aging and obesity are hypothesized to increase susceptibility to neurodegeneration, however, direct evidence in support of this hypothesis is lacking. We therefore performed a cross-sectional analysis of magnetic resonance image-based brain structure on a population-based cohort of healthy adults. Study participants were originally part of the Cambridge Centre for Ageing and Neuroscience (Cam-CAN) and included 527 individuals aged 20-87 years. Cortical reconstruction techniques were used to generate measures of whole-brain cerebral white-matter volume, cortical thickness, and surface area. Results indicated that cerebral white-matter volume in overweight and obese individuals was associated with a greater degree of atrophy, with maximal effects in middle-age corresponding to an estimated increase of brain age of 10 years. There were no similar body mass index-related changes in cortical parameters. This study suggests that at a population level, obesity may increase the risk of neurodegeneration.

Contribution of IL-10 and its -592 A/C polymorphism to cognitive functions in first-episode drug-naive schizophrenia

Numerous studies have shown that proinflammatory cytokines produced by immune cells in the brain have deleterious effects on cognitive functions. In contrast, IL-10, an anti-inflammatory cytokine, can be neuroprotective and prevent neuronal dysfunction. However, few studies have linked the role of IL-10 to cognitive deficits in schizophrenia. In this study, serum IL-10 levels and genotypes for the IL10 -592 A/C promoter polymorphism were measured in a cohort of first-episode drug-naïve schizophrenic patients (FEDN-S) (n=256) and healthy control subjects (HC) (n=540). All participants were assessed by the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), and psychopathology was assessed by the Positive and Negative Syndrome Scale (PANSS). In a separate transcriptomic data set containing 577 healthy human brain samples, we analyzed IL-10 and IL-10 RA/B-associated genetic networks in order to ascertain potential functions for IL-10 in the brain. We found a significant difference in allelic frequency between FEDN-S and HC subjects. The A allelic variant was associated with reduced serum IL-10 levels and worse attentional performance in FEDN-S but not in HC subjects. Moreover, serum IL-10 levels were correlated with the extent of cognitive impairment, especially attentional performance in the schizophrenic A-allele carriers. In human brain transcriptomic coexpression analysis, we found that genes most significantly co-expressed with IL10 were associated with synaptic vesicle transportation, and both IL10RA and IL10RB were most significantly co-expressed not only with genes that regulate inflammation but also with those that participate in synaptic formation. The IL10-592 A/C genetic variant was more common in schizophrenic patients than HC and was associated with lower IL-10 serum levels and worse attentional performance in these patients. Furthermore, the IL10 gene and its receptors in the healthy human brain appear to regulate inflammation and synaptic functions that are important for cognition, and hence its deficiency in schizophrenia may contribute to cognitive impairment.