Neuroinflammation and comorbidities are frequently ignored factors in CNS pathology

Insulin Resistance Is a Risk Factor for Overall Cerebral Small Vessel Disease Burden in Old Nondiabetic Healthy Adult Population

Background and Purpose: This study aimed to investigate the association between insulin resistance (IR) and the overall cerebral small vessel disease (CSVD) burden.

Methods: We recruited elderly, nondiabetic, healthy subjects prospectively. The overall effect of CSVD on the brain was described by a validated CSVD score. The homeostasis model assessment–estimated insulin resistance index (HOMA-IR) was used for IR estimation, and HOMA-IR ≥2.80 was defined as IR. We evaluated the association between IR and the increasing severity of CSVD score by ordinal regression models adjusting for demographics and cardiovascular risk factors.

Results: A total of 156 healthy participants were recruited. The mean age was older in the IR group than in the non-IR group (70.03 vs. 67.45, p = 0.04), and the prevalence of hypertension was significantly higher in the IR group than in the non-IR group (82.35% vs. 53.28%, p < 0.01). In ordinal regression analysis, IR was positively associated with increasing severity of the total CSVD score (adjusted odds ratio, 3.74; 95% confidence interval, 1.63–5.08; p < 0.01) after adjusting traditional risk factors. Furthermore, HOMA-IR levels showed a positive dose-dependent correlation with the total CSVD score (p < 0.01, p for trend <0.01).

Conclusions: IR is independently associated with increasing severity of the overall CSVD burden, independent of other clinical risk factors in an elderly, nondiabetic, healthy population. Furthermore, HOMA-IR level is correlated with the CSVD burden in a dose-dependent manner.

Neural stem cell therapy for stroke: A multimechanistic approach to restoring neurological function

INTRODUCTION

Neural stem cells (NSCs) have demonstrated multimodal therapeutic function for stroke, which is the leading cause of long-term disability and the second leading cause of death worldwide. In preclinical stroke models, NSCs have been shown to modulate inflammation, foster neuroplasticity and neural reorganization, promote angiogenesis, and act as a cellular replacement by differentiating into mature neural cell types. However, there are several key technical questions to address before NSC therapy can be applied to the clinical setting on a large scale.

PURPOSE OF REVIEW

In this review, we will discuss the various sources of NSCs, their therapeutic modes of action to enhance stroke recovery, and considerations for the clinical translation of NSC therapies. Understanding the key factors involved in NSC-mediated tissue recovery and addressing the current translational barriers may lead to clinical success of NSC therapy and a first-in-class restorative therapy for stroke patients.

Baseline Body Mass Predicts Average Depressive Symptoms over the Next Two Decades for White but Not Black Older Adults

Background: Although obesity and depression have a bidirectional association, this link may vary based on race. The current study tested racial variation in bidirectional links between depressive symptoms and body mass index (BMI) over 24 years of follow-up in older adults over the age of 50 in the United States. We hypothesized weaker bidirectional links in Blacks compared to Whites. Methods: Data came from waves 1 to 12 (1990 to 2014) of the Health and Retirement Study (HRS), an ongoing state-of-the-art national cohort. The study followed a representative sample of Americans (n = 15,194; 2,200 Blacks and 12,994 Whites) over the age of 50. Dependent variables were average depressive symptoms and BMI over 24 years, based on measurements every other year, from 1990 to 2014. Independent variables included baseline depressive symptoms and BMI. Covariates included age, gender, marital status, veteran status, and activities of daily living. Structural equation models were fitted to the data for data analysis. Results: In the pooled sample, bidirectional associations were found between BMI and depressive symptoms as baseline BMI predicted average depressive symptoms over time and baseline depressive symptoms predicted average BMI over 24 years. Racial differences were found in the bidirectional association between BMI and depressive symptoms, with both directions of the associations being absent for Blacks. For Whites, baseline BMI predicted average depressive symptoms over the next 24 years. Conclusion: Reciprocal associations between BMI and depressive symptoms over a 24-year period among individuals over the age of 50 vary for Blacks and Whites. As these associations are stronger for Whites than Blacks, clinical and public health programs that simultaneously target comorbid obesity and depression may be more appropriate for Whites than Blacks.

Xiao-Xu-Ming decoction extract regulates differentially expressed proteins in the hippocampus after chronic cerebral hypoperfusion

Xiao-Xu-Ming decoction has been widely used to treat stroke and sequelae of stroke. We have previously shown that the active fractions of Xiao-Xu-Ming decoction attenuate cerebral ischemic injury. However, the global protein profile and signaling conduction pathways regulated by Xiao-Xu-Ming decoction are still unclear. This study established a two-vessel occlusion rat model by bilateral common carotid artery occlusion. Rats were intragastrically administered 50 or 150 mg/kg Xiao-Xu-Ming decoction for 4 consecutive weeks. Learning and memory abilities were measured with Morris water maze. Motor ability was detected with prehensile test. Coordination ability was examined using the inclined screen test. Neuronal plasticity was observed by immunofluorescent staining. Differentially expressed proteins of rat hippocampus were analyzed by label-free quantitative proteomics. Real time-polymerase chain reaction and western blot assay were used to identify the changes in proteins. Results showed that Xiao-Xu-Ming decoction dramatically alleviated learning and memory deficits, and motor and coordination dysfunction, and increased the expression of microtubule-associated protein 2. Xiao-Xu-Ming decoction extract remarkably decreased 13 upregulated proteins and increased 39 downregulated proteins. The regulated proteins were mainly involved in oxidation reduction process, intracellular signaling cascade process, and protein catabolic process. The signaling pathways were mainly involved in ubiquitin mediated proteolysis and the phosphatidylinositol signaling system. Furthermore, there was an interaction among Rab2a, Ptpn1, Ppm1e, Cdk18, Gorasp2, Eps15, Capza2, Syngap1 and Mt-nd1. Protein analyses confirmed the changes in expression of MT-ND1. The current findings provide new insights into the molecular mechanisms of Xiao-Xu-Ming decoction extract’s effects on chronic cerebral hypoperfusion.

Age-related deregulation of TDP-43 after stroke enhances NF-κB-mediated inflammation and neuronal damage

Background

TDP-43 has been identified as a disease-associated protein in several chronic neurodegenerative disorders and increasing evidence suggests its potentially pathogenic role following brain injuries. Normally expressed in nucleus, under pathological conditions TDP-43 forms cytoplasmic ubiquitinated inclusions in which it is abnormally phosphorylated and cleaved to generate a 35 and a 25 kDa C-terminal fragments. In the present study, we investigated age-related expression patterns of TDP-43 in neurons and glia and its role as modulator of inflammation following ischemic injury.

Methods

Wild-type and TDP-43 transgenic mice of different age groups were subjected to transient middle cerebral artery occlusion. The role of TDP-43 in modulation of inflammation was assessed using immunofluorescence, Western blot analysis, and in vivo bioluminescence imaging. Finally, post-mortem stroke human brain sections were analyzed for TDP-43 protein by immunohistochemistry.

Results

We report here an age-related increase and formation of ubiquitinated TDP-43 cytoplasmic inclusions after stroke. The observed deregulation in TDP-43 expression patterns was associated with an increase in microglial activation and innate immune signaling as revealed by in vivo bioluminescence imaging and immunofluorescence analysis. The presence of ubiquitinated TDP-43 aggregates and its cleaved TDP-35 and TDP-25 fragments was markedly increased in older, 12-month-old mice leading to larger infarctions and a significant increase in in neuronal death. Importantly, unlike the hallmark neuropathological features associated with chronic neurodegenerative disorders, the TDP-43-positive cytoplasmic inclusions detected after stroke were not phosphorylated. Next, we showed that an increase and/or overexpression of the cytoplasmic TDP-43 drives the pathogenic NF-κB response and further increases levels of pro-inflammatory markers and ischemic injury after stroke in age-dependent manner. Finally, analyses of the post-mortem stroke brain tissues revealed the presence of the cytoplasmic TDP-43 immunoreactive structures after human stroke.

Conclusion

Together, our findings suggest that the level of cytoplasmic TDP-43 increases with aging and may act as an age-related mediator of inflammation and neuronal injury after stroke. Thus, targeting cytoplasmic TDP-43 may have a therapeutic potential after stroke.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1350-y) contains supplementary material, which is available to authorized users.

Learning a Foreign Language: A Review on Recent Findings About Its Effect on the Enhancement of Cognitive Functions Among Healthy Older Individuals

Currently, there is an increasing number of older population groups, especially in developed countries. This demographic trend, however, may cause serious problems, such as an increase in aging diseases, one of which is dementia whose main symptom consists in the decline of cognitive functioning. Although there has been ongoing pharmacological research on this neurological disorder, it has not brought satisfying results as far as its treatment is concerned. Therefore, governments all over the world are trying to develop alternative, non-pharmacological strategies/activities, which could help to prevent this cognitive decline while this aging population is still healthy in order to reduce future economic and social burden. One of the non-pharmacological approaches, which may enhance cognitive abilities and protect against the decline in healthy older population, seems to be the learning of a foreign language. The purpose of this mini-review article is to discuss recent findings about the effect of foreign language learning on the enhancement of cognitive functions among healthy older individuals. The findings, divided into three research areas, show that the learning of a foreign language may generate a lot of benefits for older individuals, such as enhancement of cognitive functioning, their self-esteem, increased opportunities of socializing, or reduction of costs. However, as Ware et al. (2017) indicate, any intervention program on foreign language learning should be well thought of and tailored to the needs of older people in order to be effective and avoid accompanying factors, such as older people’s anxiety or low self-confidence. Nevertheless, more empirical studies should be done in this area.

Exploration of 27 plasma immune markers: a cross-sectional comparison of 64 old psychiatric inpatients having unipolar major depression and 18 non-depressed old persons

BACKGROUND

The prevalence of major depression (MD) according to population studies is the same for old (65 years and older) and younger adults. In contrast, an elevated proportion of old MD patients are hospitalized compared to younger adults with MD, indicating a need to expand the characteristics of old inpatients with MD. To illustrate this point, the association between inflammation and MD in old psychiatric inpatients is sparsely investigated even though an association between inflammation and treatment resistance among younger adults with MD has been reported. In this study, we aimed to explore the plasma concentrations of 27 immune markers in old inpatients with MD, and our purpose was to expand the understanding of inflammatory mechanisms in these patients.

METHODS

Prior to electroconvulsive treatment of MD, we compared 64 inpatients with unipolar MD (mean age 75.2 years) and 18 non-depressed controls (mean age 78.0 years). Symptoms characterizing MD were assessed by the Hamilton Rating Scale of Depression (HRSD)-17, and the immune markers from peripheral blood plasma were analysed using multiplex assay technology. For statistical analysis of data, we used the independent samples median test, independent samples t-test, χ²-test, receiver operating characteristic curve analyses, stepwise discriminant analysis, and multivariate linear regression.

RESULTS

Twenty-two immune markers representing pro- and anti-inflammatory, adaptive and trophic signalling had higher concentrations in the inpatients compared to the controls. Only the four immune markers IL-1β, IL-5, IL-10 and IL-15 had concentrations below the lower detection limit in a considerable portion (above 20%) of the patient cases. A combination of the concentration in plasma of TNF, vascular endothelial growth factor (VEGF), IL-1β, IL-7 and monocyte chemotactic protein (MCP)-1, correctly classified 98.4% of the depressed patients and 83.3% of the non-depressed controls. Plasma concentration of TNF and VEGF were associated with the HRSD-17 scores (p = 0.017 and 0.005, respectively).

CONCLUSIONS

Our results indicate that several inflammatory mechanisms may be highly activated in old psychiatric inpatients with MD, and indicate that immune markers may contribute to a more comprehensive understanding of MD in old persons.

TRIAL REGISTRATION

NCT01559324 ClinicalTrials.gov.

Enlarged perivascular spaces in the centrum semiovale are associated with poststroke depression: A 3-month prospective study

BACKGROUND

Enlarged perivascular spaces (EPVS), markers of cerebral small vessel disease, are associated with unfavorable prognosis of stroke. This study explored the relationship between EPVS and poststroke depression (PSD).

METHODS

A total of 725 patients with acute ischemic stroke were recruited from the Stroke Unit of a university-affiliated hospital in Hong Kong. PSD was defined as a Geriatric Depression Scale score of ≥ 7 assessed at three months after stroke. The extent of EPVS in the basal ganglia (BG) and the centrum semiovale (CS) was assessed on axial T2 weighted magnetic resonance imaging using a validated scale. Patients' EPVS status was categorized as either mild or moderate to severe degree. The association between EPVS and PSD was examined with logistic regression.

RESULTS

One hundred and fifty-three (21.1%) of the study sample had PSD three month after stroke. 55.6% of the study sample were classified as having a minor stroke. The median scores of CS- and BG-EPVS were 1 (1-2) and 1 (0-2), respectively. After adjusting for demographic, clinical and imaging characteristics in multivariate logistic regression analyses, the CS-EPVS continuous score remained an independent predictor of PSD [odds ratio (OR) = 1.27; 95% confidence interval (CI) = 1.03-1.57]. After dichotomized, moderate to severe CS-EPVS was independently associated with PSD with an OR of 1.68 (95%CI = 1.10-2.57).

LIMITATIONS

The diagnosis of PSD was based on GDS score rather than a standardized clinical examination. The study favored the patients with milder stroke.

CONCLUSION

CS-EPVS were associated with PSD identified at three months after mild to moderate acute ischemic stroke.

Cerebral Small Vessel Disease Burden Is Associated With Poststroke Depressive Symptoms: A 15-Month Prospective Study

Objective: All types of cerebral small vessel disease (SVD) markers including lacune, white matter hyperintensities (WMH), cerebral microbleeds, and perivascular spaces were found to be associated with poststroke depressive symptoms (PDS). This study explored whether the combination of the four markers constituting an overall SVD burden was associated with PDS. Methods: A cohort of 563 patients with acute ischemic stroke were followed over a 15-month period after the index stroke. A score of ≥7 on the 15-item Geriatric Depression Scale was defined as clinically significant PDS. Scores of the four SVD markers ascertained on magnetic resonance imaging were summed up to represent total SVD burden. The association between SVD burden and PDS was assessed with generalized estimating equation models. Results: The study sample had a mean age of 67.0 ± 10.2 years and mild-moderate stroke [National Institutes of Health Stroke Scale score: 3, interquartile, 1-5]. PDS were found in 18.3%, 11.6%, and 12.3% of the sample at 3, 9, and 15 months after stroke, respectively. After adjusting for demographic characteristics, vascular risk factors, social support, stroke severity, physical and cognitive functions, and size and locations of stroke, the SVD burden was associated with an increased risk of PDS [odds ratio = 1.30; 95% confidence interval = 1.07-1.58; p = 0.010]. Other significant predictors of PDS were time of assessment, female sex, smoking, number of acute infarcts, functional independence, and social support. Conclusion: SVD burden was associated with PDS examined over a 15-month follow-up in patients with mild to moderate acute ischemic stroke.

Cellular and Molecular Mechanisms Underlying Non-Pharmaceutical Ischemic Stroke Therapy in Aged Subjects

The incidence of ischemic stroke in humans increases exponentially above 70 years both in men and women. Comorbidities like diabetes, arterial hypertension or co-morbidity factors such as hypercholesterolemia, obesity and body fat distribution as well as fat-rich diet and physical inactivity are common in elderly persons and are associated with higher risk of stroke, increased mortality and disability. Obesity could represent a state of chronic inflammation that can be prevented to some extent by non-pharmaceutical interventions such as calorie restriction and hypothermia. Indeed, recent results suggest that H₂S-induced hypothermia in aged, overweight rats could have a higher probability of success in treating stroke as compared to other monotherapies, by reducing post-stroke brain inflammation. Likewise, it was recently reported that weight reduction prior to stroke, in aged, overweight rats induced by caloric restriction, led to an early re-gain of weight and a significant improvement in recovery of complex sensorimotor skills, cutaneous sensitivity, or spatial memory.

CONCLUSION

animal models of stroke done in young animals ignore age-associated comorbidities and may explain, at least in part, the unsuccessful bench-to-bedside translation of neuroprotective strategies for ischemic stroke in aged subjects.

Unlocking Neurocognitive Substrates of Late-Life Affective Symptoms Using the Research Domain Criteria: Worry Is an Essential Dimension

While investigations have sought to identify the distinct and shared contributions of anxiety and depression to neurocognitive processes in late life, less is known regarding the further contribution of worry, a unique and critical dimension of affective dysregulation. Capturing the full range of symptoms, as inspired by the NIH Research Domain Criteria (RDoC), may provide finer-grained information on inter-relationships among worry, anxiety and depression on neurocognitive processing in later life. The objective of this study was to determine if the dimensional trait of worry intensifies known negative associations of dimensional measures of anxiety and depressive symptoms with neurocognitive processes, specifically cognitive control and memory processes. Using a cross-sectional and observational design, this study was conducted within a translational research center located with a Veterans medical center in Northern California. One hundred and nineteen community-residing older adults ages 65-91 years participated, and were characterized with psychiatric and neurocognitive dimensional measures. Affective symptom severity was assessed with the Penn State Worry Questionnaire, the Beck Anxiety Inventory (BAI), and the Beck Depression Inventory-II. Primary neurocognitive outcomes were inhibitory control assessed using a Stroop paradigm and delayed verbal memory assessed with the Rey Auditory Verbal Learning Test. Secondary outcomes included other less frequently examined cognitive control mechanisms (working memory, information processing, and verbal fluency) and memory processes (visual delayed memory). Contrary to prediction, the dimensional trait of worry attenuated negative associations between anxiety and depressive symptoms and inhibitory control on the one hand, and between depressive symptoms and delayed verbal memory processes on the other. In the secondary models, symptom dimensions were not associated with other cognitive control or visual delayed memory processes. Our fine-grained approach, in line with the NIMH RDoC model, suggests the neurocognitive processes associated with dimensional measures of late-life affective symptoms are dissociable. Specifically, dimensional measures of worry operate independently from other anxiety and depression symptoms to reveal differential patterns of neurocognitive processes associated with affective dysregulation.

Chronic cerebral hypoperfusion induces post-stroke dementia following acute ischemic stroke in rats

BACKGROUND

Post-stroke dementia (PSD) is one of the major consequences after stroke. Chronic cerebral hypoperfusion (CCH) can induce vascular cognitive impairment and potentiate amyloid pathology. We investigated how CCH contributes to the development of PSD after stroke in the context of neuroinflammation and amyloid pathology.

METHODS

We designed a unique animal model for PSD. We performed middle cerebral artery occlusion (MCAO) surgery in rats mimicking acute territorial infarct, which was followed by bilateral common carotid artery occlusion (BCCAo) surgery mimicking CCH. We performed behavioral tests including neurologic function test and water maze task and histological investigations including neuroinflammation, neuronal cell death, amyloid pathology, and aquaporin 4 (AQP4) distribution.

RESULTS

Spatial memory was synergistically impaired when BCCAo was superimposed on MCAO. Neuroinflammation with astroglial or microglial activation and amyloid pathology were enhanced in the ipsilateral cortex, thalamus, and hippocampus when BCCAo was superimposed on MCAO. Glymphatic pathway-related AQP4 distribution changed from perivascular to parenchymal pattern.

CONCLUSIONS

Our experimental results suggest that CCH may contribute to the development of PSD by interfering with amyloid clearance through the glymphatic pathway and concomitant neuroinflammation. Therapeutic strategy to clear brain metabolic waste through the glymphatic pathway may be a promising approach to prevent PSD after stroke.

A roadmap for investigating the role of the prion protein in depression associated with neurodegenerative disease

The physiological properties of the native, endogenous prion protein (PrP(C)) is a matter of concern, due to its pleiotropic functions and links to neurodegenerative disorders and cancer. In line with our hypothesis that the basic function of PrP(C) is to serve as a cell surface scaffold for the assembly of signaling modules, multiple interactions have been identified of PrP(C) with signaling molecules, including neurotransmitter receptors. We recently reported evidence that PrP(C) may modulate monoaminergic neurotransmission, as well as depressive-like behavior in mice. Here, we discuss how those results, together with a number of other studies, including our previous demonstration that both inflammatory and behavioral stress modulate PrP(C) content in neutrophils, suggest a distributed role of PrP(C) in clinical depression and inflammation associated with neurodegenerative diseases. An overarching understanding of the multiple interventions of PrP(C) upon physiological events may both shed light on the pathogenesis of, as well as help the identification of novel therapeutic targets for clinical depression, Prion and Alzheimer's Diseases.

Post-stroke Fatigue and Depressive Symptoms Are Differentially Related to Mobility and Cognitive Performance

Background: Fatigue and depressive symptoms are common and often inter-related stroke sequelae. This study investigates how they are related, directly or indirectly, to mobility and cognitive outcomes within 6 months of stroke.

Methods: Participants were recruited from 4 stroke centers in Ontario, Canada. Post-stroke fatigue was assessed using the Fatigue Assessment Scale (FAS). Depressive symptoms were screened using the Center for Epidemiological Studies Scale for Depression (CES-D). Factor analyses were used to construct scores from mobility (distance traveled during a 2-min walk test, Chedoke-McMaster Stroke Assessment leg score, and Berg Balance Scale total score) and cognitive (Montreal Cognitive Assessment, Trail-Making Tests A and B, and five-word free recall) tests. Direct associations were assessed in linear regression models and indirect effects were assessed in path models. Covariates were age, sex, education, antidepressant use, days since stroke, and stroke severity (National Institute of Health Stroke Severity Scale score).

Results: Fatigue and depressive symptoms were highly correlated (r > 0.51, p < 0.0001). Depressive symptoms were associated with cognition (β = −0.184, p = 0.04) and indirectly with mobility, mediated by fatigue (indirect effect = −0.0142, 95% CI: −0.0277 to −0.0033). Fatigue was associated with mobility (β = −0.253, p = 0.01), and indirectly with cognition, mediated by depressive symptoms (indirect effect = −0.0113, 95% CI: −0.0242 to −0.0023).

Conclusions: Fatigue and depressive symptoms are related distinctly to cognitive and mobility impairments post-stroke. Fatigue was associated with poorer lower limb motor function, and with cognition indirectly via depressive symptoms.

Age-Related Frontal Periventricular White Matter Hyperintensities and miR-92a-3p Are Associated with Early-Onset Post-Stroke Depression

Objective: To explore the correlationship among white matter hyperintensities (WMHs), miR-92a-3p and early-onset post-stroke depression (PSD). Methods: We recruited consecutively 238 patients with acute cerebral infarction and MRI examination in the Department of neurology, Ruijin hospital, Shanghai Jiaotong University School of Medicine. The diagnosis of early-onset PSD was made in accordance with DSM-IV criteria for depression in 2 weeks after stroke. Clinical information and assessments of stroke severity were recorded on admission. The analysis of plasma miR-92a-3p was performed using quantitative PCR at the same time. WMHs were evaluated by the Fazekas and Scheltens visual rating scales. The relationship among WMHs, miR-92a-3p and PSD were analyzed by SPSS 22.0 software. Results: Logistic regression demonstrated that periventricular WMHs (PVWMHs) in frontal caps was an independent risk factor with early-onset PSD (OR = 1.579, 95% CI: 1.040-2.397, p = 0.032). The age and numbers of lacunes were related to frontal PVWMHs. Plasma miR-92a-3p in the PSD group was higher compared with the non-depressed group. Receiver operating curve analysis revealed that miR-92a-3p could predict early-onset PSD with 90% sensitivity and 90% specificity. The higher miR-92a-3p trended toward association with greater frontal PVWMHs. Conclusion: Acute ischemic stroke patients with frontal PVWMHs or a high plasma miR-92a-3p at baseline were more likely to develop early-onset PSD. MiR-92a-3p might be involved in the white matter impairment and post-stroke depression.

Triggering Receptor Expressed on Myeloid Cells 2, a Novel Regulator of Immunocyte Phenotypes, Confers Neuroprotection by Relieving Neuroinflammation

BACKGROUND

Microglia can not only detrimentally augment secondary injury but also potentially promote recovery. However, the mechanism underlying the regulation of microglial phenotypes after stroke remains unclear.

METHODS

Mice were subjected to middle cerebral artery occlusion for 60 min. At 3 days after reperfusion, the effects of activation and suppression of triggering receptor expressed on myeloid cells 2 on immunocyte phenotypes (n = 5), neurobehavioral scores (n = 7), infarct volumes (n = 8), and neuronal apoptosis (n = 7) were analyzed. In vitro, cultured microglia were exposed to oxygen-glucose deprivation for 4 h. Inflammatory cytokines, cellular viability (n = 8), neuronal apoptosis (n = 7), and triggering receptor expressed on myeloid cells 2 expression (n = 5) were evaluated in the presence or absence of triggering receptor expressed on myeloid cell-specific small interfering RNA or triggering receptor expressed on myeloid cells 2 overexpression lentivirus.

RESULTS

Triggering receptor expressed on myeloid cells 2 expression in the ischemic penumbra peaked at 3 days after ischemia-reperfusion injury (4.4 ± 0.1-fold, P = 0.0004) and was enhanced in interleukin-4/interleukin-13-treated microglia in vitro (1.7 ± 0.2-fold, P = 0.0119). After oxygen-glucose deprivation, triggering receptor expressed on myeloid cells 2 conferred neuroprotection by regulating the phenotypic conversion of microglia and inflammatory cytokine release. Intraperitoneal administration of triggering receptor expressed on myeloid cells 2 agonist heat shock protein 60 or unilateral delivery of a recombinant triggering receptor expressed on myeloid cells 2 lentivirus into the cerebral ventricle induced a significant neuroprotective effect in mice (apoptotic neurons decreased to 31.3 ± 7.6%; infarct volume decreased to 44.9 ± 5.3%). All values are presented as the mean ± SD.

CONCLUSIONS

Activation or up-regulation of triggering receptor expressed on myeloid cells 2 promoted the phenotypic conversion of microglia and decreased the number of apoptotic neurons. Our study suggests that triggering receptor expressed on myeloid cells 2 is a novel regulator of microglial phenotypes and may be a potential therapeutic target for stroke.

Hypoxia in CNS Pathologies: Emerging Role of miRNA-Based Neurotherapeutics and Yoga Based Alternative Therapies

Cellular respiration is a vital process for the existence of life. Any condition that results in deprivation of oxygen (also termed as hypoxia) may eventually lead to deleterious effects on the functioning of tissues. Brain being the highest consumer of oxygen is prone to increased risk of hypoxia-induced neurological insults. This in turn has been associated with many diseases of central nervous system (CNS) such as stroke, Alzheimer's, encephalopathy etc. Although several studies have investigated the pathophysiological mechanisms underlying ischemic/hypoxic CNS diseases, the knowledge about protective therapeutic strategies to ameliorate the affected neuronal cells is meager. This has augmented the need to improve our understanding of the hypoxic and ischemic events occurring in the brain and identify novel and alternate treatment modalities for such insults. MicroRNA (miRNAs), small non-coding RNA molecules, have recently emerged as potential neuroprotective agents as well as targets, under hypoxic conditions. These 18-22 nucleotide long RNA molecules are profusely present in brain and other organs and function as gene regulators by cleaving and silencing the gene expression. In brain, these are known to be involved in neuronal differentiation and plasticity. Therefore, targeting miRNA expression represents a novel therapeutic approach to intercede against hypoxic and ischemic brain injury. In the first part of this review, we will discuss the neurophysiological changes caused as a result of hypoxia, followed by the contribution of hypoxia in the neurodegenerative diseases. Secondly, we will provide recent updates and insights into the roles of miRNA in the regulation of genes in oxygen and glucose deprived brain in association with circadian rhythms and how these can be targeted as neuroprotective agents for CNS injuries. Finally, we will emphasize on alternate breathing or yogic interventions to overcome the hypoxia associated anomalies that could ultimately lead to improvement in cerebral perfusion.

Ischemic stroke: experimental models and reality

The vast majority of cerebral stroke cases are caused by transient or permanent occlusion of a cerebral blood vessel (“ischemic stroke”) eventually leading to brain infarction. The final infarct size and the neurological outcome depend on a multitude of factors such as the duration and severity of ischemia, the existence of collateral systems and an adequate systemic blood pressure, etiology and localization of the infarct, but also on age, sex, comorbidities with the respective multimedication and genetic background. Thus, ischemic stroke is a highly complex and heterogeneous disorder. It is immediately obvious that experimental models of stroke can cover only individual specific aspects of this multifaceted disease. A basic understanding of the principal molecular pathways induced by ischemia-like conditions comes already from in vitro studies. One of the most frequently used in vivo models in stroke research is the endovascular suture or filament model in rodents with occlusion of the middle cerebral artery (MCA), which causes reproducible infarcts in the MCA territory. It does not require craniectomy and allows reperfusion by withdrawal of the occluding filament. Although promptly restored blood flow is far from the pathophysiology of spontaneous human stroke, it more closely mimics the therapeutic situation of mechanical thrombectomy which is expected to be increasingly applied to stroke patients. Direct transient or permanent occlusion of cerebral arteries represents an alternative approach but requires craniectomy. Application of endothelin-1, a potent vasoconstrictor, allows induction of transient focal ischemia in nearly any brain region and is frequently used to model lacunar stroke. Circumscribed and highly reproducible cortical lesions are characteristic of photothrombotic stroke where infarcts are induced by photoactivation of a systemically given dye through the intact skull. The major shortcoming of this model is near complete lack of a penumbra. The two models mimicking human stroke most closely are various embolic stroke models and spontaneous stroke models. Closeness to reality has its price and goes along with higher variability of infarct size and location as well as unpredictable stroke onset in spontaneous models versus unpredictable reperfusion in embolic clot models.

Potential unfavorable impacts of BDNF Val66Met polymorphisms on metabolic risks in average population in a longevous area

Background

Brain-derived neurotrophic factor (BDNF) has been implicated in cognitive performance and the modulation of several metabolic parameters in some disease models, but its potential roles in successful aging remain unclear. We herein sought to define the putative correlation between BDNF Val66Met and several metabolic risk factors including BMI, blood pressure, fasting plasma glucose (FPG) and lipid levels in a long-lived population inhabiting Hongshui River Basin in Guangxi.

Methods

BDNF Val66Met was typed by ARMS-PCR for 487 Zhuang long-lived individuals (age ≥ 90, long-lived group, LG), 593 of their offspring (age 60–77, offspring group, OG) and 582 ethnic-matched healthy controls (aged 60–75, control group, CG) from Hongshui River Basin. The correlations of genotypes with metabolic risks were then determined.

Results

As a result, no statistical difference was observed on the distribution of allelic and genotypic frequencies of BDNF Val66Met among the three groups (all P > 0.05) except that AA genotype was dramatically higher in females than in males of CG. The HDL-C level of A allele (GA/AA genotype) carriers was profoundly lower than was non-A (GG genotype) carriers in the total population and the CG (P = 0.009 and 0.006, respectively), which maintained in females, hyperglycemic and normolipidemic subgroup of CG after stratification by gender, BMI, glucose and lipid status. Furthermore, allele A carriers, with a higher systolic blood pressure, exhibited 1.63 folds higher risk than non-A carriers to be overweight in CG (OR = 1.63, 95% CI: 1.05 - 2.55, P = 0.012). Multiple regression analysis displayed that the TC level of LG reversely associated with BDNF Val66Met genotype.

Conclusions

These data suggested that BDNF 66Met may play unfavorable roles in blood pressure and lipid profiles in the general population in Hongshui River area which might in part underscore their poorer survivorship versus the successful aging individuals and their offspring.

Electronic supplementary material

The online version of this article (doi:10.1186/s12877-016-0393-0) contains supplementary material, which is available to authorized users.

Dementia, Preclinical Studies in Neurodegeneration and its Potential for Translational Medicine in South America

Latin-American people with dementia will increase to an astounding 368% in 2050, higher than USA and Europe. In addition, to sporadic dementia type like Alzheimer, and vascular dementia (VaD) progression after Cerebrovascular disease is also found. These incidences are increased in Colombia by specific populations affected with pure Neurodegenerative and VaDs like Autosomical Dominant familial Alzheimer’s disease (AD) and Cerebral Autosomal-Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL). In spite of the enormous human effort with and economical effort and investment costs, neither sporadic nor genetic kinds of dementia progression have been prevented or blocked yet. Currently, there exist several animal models that partially solve the understanding of the neurodegenerative etiopathogenesis and its treatment. However, when the potential therapies are translated to humans, those do not work or present a limited action. Main difficulties are the diverse comorbility associated to the cause and/or several affected brain regions, reducing the efficacy of some therapies which are limited to a tissue-specific action or modulating a kind of neurotransmission. Global investigation suggests that a general prevention could be achieved with the improvement in the quality of lifestyle, including healthy diet, physical and mental activity, and avoiding mechanical or chemical pro-inflammatory events in an early stage in the most of non-communicable diseases. In this review article, we present some molecular targets and preclinical studies in animal models to propose strategies that could be useful in a future translation to prevent or block neurodegeneration: one is gene therapy; silencing pathogenic genes in critical brain areas where excitotoxicity arise and spread. Another is to take advantage of the natural source and its wide biodiversity of natural products that are capable of identifying, by the blocking and prevention of neurodegeneration. On the other side, the casuistic of pure dementias in the Latin-American region gives an exceptional opportunity to understand the pathogenesis in these human populations. Further, this is in support of the basic and clinical researchers working on an interaction for a better understanding and medical care of mixed dementias, which have more complex factors than pure ones. However, to promote the translation of any therapeutical alternative is necessary to clarify the normative and the protocols for developing clinical trials with original candidates or work upon strategies proposed from South-American countries.

A longitudinal study of depression and gestational diabetes in pregnancy and the postpartum period

AIMS/HYPOTHESIS

Depression and glucose intolerance commonly co-occur among non-pregnant individuals; however, the temporal relationship between gestational diabetes (GDM) and depression during pregnancy and the postpartum period is less understood. Our objective was to assess longitudinal associations between depression early in pregnancy and GDM risk, as well as GDM and subsequent risk of postpartum depression.

METHODS

Data came from the prospective National Institute of Child Health and Human Development Fetal Growth Studies-Singleton cohort (2009-2013), and had been collected at 12 US clinical centres. Pregnant women without psychiatric disorders, diabetes or other chronic conditions before pregnancy were followed throughout pregnancy (n = 2477). Only women with GDM and matched controls were followed up at 6 weeks postpartum (n = 162). GDM was ascertained by a review of the medical records. Depression was assessed in the first (8-13 gestational weeks) and second (16-22 weeks) trimesters and at 6 weeks postpartum using the Edinburgh Postnatal Depression Scale. Postpartum depression was defined as a depressive symptom score ≥10 or antidepressant medicine use after delivery. RR and 95% CI were adjusted for pre-pregnancy BMI and other risk factors. GDM was considered to be the outcome for the first set of analyses, with depression in the first and second trimesters as the exposures. Postpartum depression was considered as the outcome for the second set of analyses, with GDM as the exposure.

RESULTS

Overall, comparing the highest and lowest quartiles of first-trimester depression scores, the scores from the highest quartile were associated with a significant twofold (95% CI 1.06, 3.78) increased risk of GDM, but this was attenuated to 1.72-fold (95% CI 0.92, 3.23) after adjustment; the second-trimester results were similar. The risk was stronger and significant in both trimesters among non-obese women (p for trend 0.02 and 0.01, respectively), but null for obese women. Women with persistently high depression scores in both trimesters had the greatest risk of GDM (highest vs lowest quartile in both trimesters: adjusted RR 3.21, 95% CI 1.00, 10.28). GDM was associated with an adjusted 4.62-fold (95% CI 1.26, 16.98) increased risk of subsequent postpartum depression.

CONCLUSIONS/INTERPRETATION

This prospective study demonstrates a modest association between depressive symptoms early in pregnancy and an increased risk of incident GDM, as well as between GDM and subsequent postpartum depression risk, highlighting pregnancy and the postpartum period as an important susceptible time window during the life course for the interplay between depression and glucose intolerance phenotypes. GDM risk associated with elevated depressive symptoms was particularly high among non-obese women and women with symptoms persisting across the first two trimesters of pregnancy.

Impaired White Matter Connections of the Limbic System Networks Associated with Impaired Emotional Memory in Alzheimer's Disease

Background: Discrepancies persist regarding retainment of emotional enhancement of memory (EEM) in mild cognitive impairment (MCI) and early Alzheimer's disease (AD) patients.In addition, the neural mechanisms are still poorly understood, little is known about emotional memory related changes in white matter (WM). Objective: To observe whether EEM is absent in amnestic MCI (aMCI) and AD patients, and to investigate if emotional memory is associated with WM connections and gray matters (GM) of the limbic system networks. Methods: Twenty-one AD patients, 20 aMCI patients and 25 normal controls participated in emotional picture recognition tests and MRI scanning. Tract-based spatial statistics (TBSS) and voxel-based morphometry (VBM) methods were used to determine white and gray matter changes of patients. Fourteen regions of interest (ROI) of WM and 20 ROIs of GM were then selected for the correlation analyses with behavioral scores. Results: The EEM effect was lost in AD patients. Both white and gray matter of the limbic system networks were impaired in AD patients. Significant correlations or tendencies between the bilateral uncinate fasciculus, corpus callosum (genu and body), left cingulum bundle, left parahippocampal WM and the recognition sensitivity of emotional valence pictures, and significant correlations or tendencies between the splenium of corpus callosum, left cingulum bundle, left crus of fornix and stria terminalis and the recognition sensitivity of EEM were found. The volume of left amygdala, bilateral insula, medial frontal lobe, anterior and middle cingulum gyrus were positively correlated with the recognition sensitivity of emotional photos, and the right precuneus was positively correlated with the negative EEM effect. However, the affected brain areas of aMCI patients were more localized, and aMCI patients benefited only from positive stimuli. Conclusion: There are impairments of the limbic system networks of AD patients. Damaged WM connections and GM volumes of those networks are associated with impaired emotional memory and EEM effect in AD patients.

Environmental Enrichment Modified Epigenetic Mechanisms in SAMP8 Mouse Hippocampus by Reducing Oxidative Stress and Inflammaging and Achieving Neuroprotection

With the increase in life expectancy, aging and age-related cognitive impairments are becoming one of the most important issues for human health. At the same time, it has been shown that epigenetic mechanisms are emerging as universally important factors in life expectancy. The Senescence Accelerated Mouse P8 (SAMP8) strain exhibits age-related deterioration evidenced in learning and memory abilities and is a useful model of neurodegenerative disease. In SAMP8, Environmental Enrichment (EE) increased DNA-methylation levels (5-mC) and reduced hydroxymethylation levels (5-hmC), as well as increased histone H3 and H4 acetylation levels. Likewise, we found changes in the hippocampal gene expression of some chromatin-modifying enzyme genes, such as Dnmt3b. Hdac1. Hdac2. Sirt2, and Sirt6. Subsequently, we assessed the effects of EE on neuroprotection-related transcription factors, such as the Nuclear regulatory factor 2 (Nrf2)-Antioxidant Response Element pathway and Nuclear Factor kappa Beta (NF-κB), which play critical roles in inflammation. We found that EE produces an increased expression of antioxidant genes, such as Hmox1. Aox1, and Cox2, and reduced the expression of inflammatory genes such as IL-6 and Cxcl10, all of this within the epigenetic context modified by EE. In conclusion, EE prevents epigenetic changes that promote or drive oxidative stress and inflammaging.

The effects of fisetin on lipopolysaccharide-induced depressive-like behavior in mice

Major depressive disorder (MDD) involves a series of pathological changes including the inflammation and increased cytokine levels. Fisetin, a natural flavonoid, has anti-inflammatory and antioxidant, and also has been shown in our previous studies to exert anti-depressant-like properties. The present study aimed to investigate the effect of fisetin on lipopolysaccharide (LPS)-induced depressive-like behavior and inflammation in mice. The results suggested that the immobility time in the forced swimming test (FST) and tail suspension test (TST) were increased at 6 h, 12 h and 24 h after LPS injection (0.83 mg/kg). However, only the group of 24 h treatment did not show any effect on locomotion counts. Pretreatment with fisetin at doses of 20, 40 and 80 mg/kg (p.o.) for 7 days reversed LPS-induced alterations of the immobility time in both of these two tests. Further neurochemical assays suggested that pretreatment with fisetin reversed LPS-induced overexpression of pro-inflammatory cytokine (IL-1β, IL-6 and TNF-α) in the hippocampus and the prefrontal cortex (PFC). Moreover, higher dose of fisetin effectively antagonized iNOS mRNA expression and nitrite levels via the modulation of NF-κB in the hippocampus and PFC. Taken together, fisetin may be an effective therapeutic agent for LPS-induced depressive-like behaviors, which is due to its anti-inflammatory property.

Adult obese mice suffer from chronic secondary brain injury after mild TBI

Background

A traumatic brain injury (TBI) event is a devastating injury to the brain that may result in heightened inflammation, neurodegeneration, and subsequent cognitive and mood deficits. TBI victims with co-morbidities such as heart disease, diabetes, or obesity may be more vulnerable to the secondary brain injury that follows the initial insult. Compared to lean individuals, obese subjects tend to have worse clinical outcomes and higher mortality rates after trauma.

Methods

To elucidate whether obesity predisposes individuals to worse outcomes after TBI, we subjected adult lean and obese male/female mice to a mild TBI. The injury was administered using a controlled skull impact (CSI) device. Lean or obese 6-month-old C57 BL/6 mice were subjected once to a mild TBI. Additionally, at day 30 after injury, both the lean and obese mice were tested for increased anxiety using the open field test.

Results

At day 30 after TBI, compared to the lean mice, we found heightened microglial (MG) activation in the cerebral cortex, corpus callosum, and hypothalamus. Another compelling finding was that, compared to the non-injured obese male control mice, the obese TBI mice had a decrease in the rate of weight gain and serum corticosterone levels at day 30 after injury. Additionally, the injured obese mice displayed higher levels of anxiety as determined by a significant decrease in time spent in the non-peripheral zones in the open field test. In contrast to the obese males, the obese female mice did not exhibit increases in the number of active MG in the brain, changes in weight gain/corticosterone levels, or increased anxiety at day 30 after TBI.

Conclusions

The data presented here suggests that obese mice have worse outcomes compared to lean mice after mild TBI. Also, the obese males have worse outcomes than the injured female mice. This data may explain the sequela of chronic secondary brain injury in obese adults after a single mild TBI. Also, this report may help shape how the overweight/obese populations are monitored over the days and months following a TBI.

Glial Modulation by N-acylethanolamides in Brain Injury and Neurodegeneration

Neuroinflammation involves the activation of glial cells and represents a key element in normal aging and pathophysiology of brain damage. N-acylethanolamides (NAEs), naturally occurring amides, are known for their pro-homeostatic effects. An increase in NAEs has been reported in vivo and in vitro in the aging brain and in brain injury. Treatment with NAEs may promote neuroprotection and exert anti-inflammatory actions via PPARα activation and/or by counteracting gliosis. This review aims to provide an overview of endogenous and exogenous properties of NAEs in neuroinflammation and to discuss their interaction with glial cells.

A Lebanese dietary pattern promotes better diet quality among older adults: findings from a national cross-sectional study

Background

Proper nutrition is critical for healthy aging and maintaining functional independence. Limited research has been done on the assessment of dietary patterns of older adults and their association with diet quality indices. This study was conducted to identify, characterize, and evaluate the dietary patterns and diet quality of older adults in Lebanon, a middle-income country undergoing nutrition transition.

Methods

A cross-sectional population-based study was conducted on a nationally representative sample of community-dwelling older adults aged >50 years (n = 525). Socio-demographic, anthropometric, and lifestyle variables were collected through interviews, and dietary intake was assessed using a semi-quantitative food frequency questionnaire (FFQ). Five commonly used diet quality indices (DQIs) were calculated, including the Alternative Healthy Eating Index (AHEI), the alternate Mediterranean diet score (aMed), the Dietary Approach to Stop Hypertension (DASH) style diet score, and the Lebanese Mediterranean Diet index. Dietary patterns (DPs) were derived using exploratory factor analysis. Associations of identified DPs with energy, energy-adjusted nutrients, and DQIs were evaluated by Pearson’s correlations. Multiple linear regression analyses were used to examine correlates of DPs.

Results

Three DPs were derived: Lebanese, Western, and High Protein/Alcohol patterns. The Lebanese pattern had highest correlations with fiber, folate, vitamin C, and all five DQIs. The Western was positively associated with energy and sodium and was inversely correlated with fiber, most vitamins, and a number of DQIs, namely AHEI, aMED, and DASH-style diet score. Highest correlations with intakes of proteins and fat were observed for the High Protein/Alcohol pattern. The Lebanese pattern was associated with female gender, education, nonsmoking and physical activity, whereas the Western pattern was associated with adverse health behaviors, including smoking, skipping breakfast, and physical inactivity.

Conclusions

Of the three identified patterns, the Lebanese DP was associated with better diet quality and healthier lifestyle behaviors while the Western pattern implicated a lower quality diet. Public health programs promoting prudent diets, including the Mediterranean and Lebanese DPs, are needed to improve the diet quality of middle-aged and older adults in an attempt to improve their functionality and quality of life.

Long-Term Outcomes after Stroke in Elderly Patients with Atrial Fibrillation: A Hospital-Based Follow-Up Study in China

Background: Atrial fibrillation (AF) significantly increases the risk of stroke and disease burden; it is an established predictor of poor outcomes after stroke. However, reported differences in outcomes after stroke among elderly patients between AF and non-AF group are conflicting. We aimed to compare differences in outcomes at 1 year and 3 years after stroke among elderly patients (aged ≥ 75 years old) between AF group and non-AF group.

Methods: We recruited 1070 consecutive elderly patients who experienced acute ischemic stroke between January 2008 and December 2013 in Jiamusi University First Hospital, China in this study. Information regarding stroke subtype, severity, risk factors, and outcome (mortality, dependency, and recurrence) at 3 and 12 months after stroke were recorded and assessed between AF group and non-AF group.

Results: The prevalence of AF was 16.1% overall, with a similar trend in the prevalence of AF between men and women. The AF group were more likely to experience severe stroke compared to the non-AF group (32.0 vs. 11.9%, respectively; P < 0.001). There were no obvious differences between groups regarding the prevalence of hypertension, dyslipidemia, obesity, current smoking, and alcohol drinking but there was a higher prevalence of diabetes in the non-AF group (20.3 vs. 30.1%, P = 0.010). Mortality and dependency rates were significantly higher in the AF group than in the non-AF group at 1 year after stroke (29.6 vs. 17.8%, P = 0.001 for mortality; and 59.5 vs. 36.1%, P = 0.010 for dependency) and 3 years after stroke (46.1 vs. 33.2%, P = 0.032 for mortality; and 70.7 vs. 49.2%, P = 0.010 for dependency); however, there was no significant between-groups differences in rates of recurrence across the follow-up periods. The results for dependency remained stable after adjustment for sex, stroke severity, and stroke risk factors at 3 years after stroke (OR, 2.26; 95% CI, 1.06–4.81; P = 0.034); however, the relationship between AF and mortality and recurrence disappeared after adjusting for these covariates

Conclusion: These findings suggest that it is crucial to highlight the treatment of elderly stroke patients with AF in order to reduce poor outcomes among the elderly and to reduce the burden of AF in China.

Abnormal Subcortical Brain Morphology in Patients with Knee Osteoarthritis: A Cross-sectional Study

Despite the involvement of subcortical brain structures in the pathogenesis of chronic pain and persistent pain as the defining symptom of knee osteoarthritis (KOA), little attention has been paid to the morphometric measurements of these subcortical nuclei in patients with KOA. The purpose of this study is to explore the potential morphological abnormalities of subcortical brain structures in patients with KOA as compared to the healthy control subjects by using high-resolution MRI. Structural MR data were acquired from 26 patients with KOA and 31 demographically similar healthy individuals. The MR data were analyzed by using FMRIB’s integrated registration and segmentation tool. Both volumetric analysis and surface-based shape analysis were performed to characterize the subcortical morphology. The normalized volumes of bilateral caudate nucleus were significantly smaller in the KOA group than in the control group (P = 0.004). There was also a trend toward smaller volume of the hippocampus in KOA as compared to the control group (P = 0.027). Detailed surface analyses further localized these differences with a greater involvement of the left hemisphere (P < 0.05, corrected) for the caudate nucleus. Hemispheric asymmetry (right larger than left) of the caudate nucleus was found in both KOA and control groups. Besides, no significant correlation was found between the structural data and pain intensities. Our results indicated that patients with KOA had statistically significant smaller normalized volumes of bilateral caudate nucleus and a trend toward smaller volume of the hippocampus as compared to the control subjects. Further investigations are necessary to characterize the role of caudate nucleus in the course of chronicity of pain associated with KOA.

Patients with depression display cytokine levels in serum and cerebrospinal fluid similar to patients with diffuse neurological symptoms without a defined diagnosis

INTRODUCTION

Several reports indicate that inflammation may play a role in depression and demonstrate enhanced systemic levels of inflammatory mediators. We hypothesized that 44 patients with a diagnosis of depression would present with a specific and different serum and cerebrospinal fluid (CSF) cytokine profile compared to 21 patients with diffuse neurological symptoms, of whom 15 had fatigue as a major symptom, but no change in emotional state.

METHODS

The diagnoses of the patients with depression were according to the International Classification of Diseases, tenth edition (F32-34 spectra). Cytokine profiles in serum and CSF were determined by multiplex analysis, including 27 cytokines, chemokines, and growth factors.

RESULTS

No differences could be found between the two groups studied regarding cytokine levels in serum or CSF except for serum interleukin (IL)-1 receptor antagonist that was lower in the depression group. There were only four high correlations (>0.4) between serum and CSF levels of the cytokines, reflecting independent synthesis and turnover in these two compartments. In the control group, fatigue was associated with increased IL-1 receptor antagonist, IL-10, granulocyte-colony stimulating factor, and interferon-γ (all P<0.01).

CONCLUSION

Patients with depression had a similar cytokine profile as nondepressive patients, both systemically and in CSF. Fatigue was associated with higher levels of some inflammatory markers in the control group. It is possible that the presence of fatigue in a large proportion of patients and controls could contribute to the lack of difference in cytokine levels between these two groups.