S100beta induces neuronal cell death through nitric oxide release from astrocytes

Unraveling the potential of neuroinflammation and autophagy in schizophrenia

Schizophrenia (SCZ) is a complex and chronic psychiatric disorder that affects a significant proportion of the global population. Although the precise etiology of SCZ remains uncertain, recent studies have underscored the involvement of neuroinflammation and autophagy in its pathogenesis. Neuroinflammation, characterized by hyperactivated microglia and markedly elevated pro-inflammatory cytokines, has been observed in postmortem brain tissues of SCZ patients and is closely associated with disease severity. Autophagy, a cellular process responsible for eliminating damaged components and maintaining cellular homeostasis, is believed to play a pivotal role in neuronal health and the onset of SCZ. This review explores the roles and underlying mechanisms of neuroinflammation and autophagy in SCZ, with a particular focus on their intricate interplay. Additionally, we provide an overview of potential therapeutic strategies aimed at modulating neuroinflammation and autophagy, including nutritional interventions, anti-inflammatory drugs, antipsychotics, and plant-derived natural compounds. The review also addresses the dual effects of antipsychotics on autophagy. Our objective is to translate these insights into clinical practice, expanding the therapeutic options available to improve the overall health and well-being of individuals with SCZ.

Transient ocular hypertension remodels astrocytes through S100B

Glaucoma is a series of irreversible and progressive optic nerve degenerations, often accompanied by astrocyte remodeling as the disease progresses, a process that is insufficiently understood. Here, we investigated the morphology of retinal and optic nerve head (ONH) astrocytes under mechanical stress, and explored whether a specific phase is present that precedes astrocyte remodeling. A mouse model of transient ocular hypertension (OHT) and an in vitro cell stretch model were established to mimic the pathological conditions of increased intraocular pressure and mechanical stress on cultured cells. Glial fibrillary acidic protein (GFAP), S100B, and actin staining were used to characterize astrocyte morphology and cytoskeleton, with qPCR used to measure mRNA expression. We also silenced S100B expression and conduct RNA sequencing on ONH astrocytes. Astrocytes displayed weaker GFAP intensity (p < 0.0001) in the early-stage OHT mouse model, prior to the onset of hypertrophy, which was accompanied by an increase in GFAP mRNA expression (p < 0.0001) and a decrease in S100B mRNA expression (p < 0.001). In vitro-stretched astrocytes tended to contract and had fewer cellular processes and more elongated cell bodies. Downregulation of S100B expression occurred in in both the in vivo (p = 0.0001) and in vitro (p = 0.0023) models. S100B-silenced ONH astrocytes were similarly characterized by a slender morphology. In the RNA-seq analysis, genes downregulated by more than fivefold were predominantly enriched in terms related to nutrient metabolism, motor proteins and morphogenesis. Meanwhile, genes upregulated by more than fivefold were primarily associated with terms related to histone modification and visual perception. As an early response to mechanical stress, S100B expression is downregulated in astrocytes, which assume a slender morphology, reminiscent of cell "weakening." Silencing intracellular S100B expression induced similar morphology changes and altered the transcriptome. Stress-induced changes were reversible, with evidence of enhanced late-stage reactivation that is likely related to S100B.

Expression of S100β during mouse cochlear development

In the present study, the expression of S100β was examined in the mouse cochlea from embryonic day 17 (E17) to postnatal day 32 (P32) using immunofluorescence, aiming to explore its possible role in auditory system. At E17, S100β expression was not detected, except in the external cochlear wall. Starting at E18.5, S100β staining appeared in the organ of Corti and the stria vascularis. In the E18.5 and P1 organ of Corti, S100β was confined to the developing pillar cells. By P6, cytoplasmic staining of S100β was evident in the inner and outer pillar cells, forming the tunnel of Corti. Additionally, S100β expression extended medially into the three rows of Deiter's cells, with labeling of their phalangeal processes. At P8, S100β continued to be expressed in the heads, bodies, and feet of the two pillar cells, as well as in the soma and phalangeal processes of the three rows of Deiter's cells. In the lateral wall of the P8 cochlea, S100β was expressed not only in the stria vascularis but also in the spiral ligament. Between P10 and P12, S100β expression was maintained in the Deiter's cells and pillar cells of the organ of Corti, as well as in the lateral wall, and spiral limbus. From P14 onwards, S100β expression ceased in the stria vascularis, though it persisted in the spiral ligament and spiral limbus into adulthood. Within the P14 and P21 organ of Corti, S100β remained in the Deiter's and pillar cells. S100β immunostaining was not observed in the phalangeal processes of Deiter's cells but was specifically present in the Deiter's cell cups at P21. In the adult cochlea (P28 and P32), S100β expression declined in both Deiter's and pillar cells. The dynamic spatiotemporal changes in S100β expression during cochlear ontogeny suggest its role in cochlear development and hearing function.

Serum protein S-100B as a novel biomarker of diagnosis and prognosis of childhood epilepsy

Background

Elevated levels of S-100B in serum are increasingly considered a potential biochemical marker of nervous system damage. To our knowledge, limited number of research studies have tested the serum S-100B protein levels in children with epilepsy. The objective of our study is to measure the serum levels of S-100B protein in pediatric cases with epilepsy.

Results

The mean serum concentration of S-100B protein was 0.135 ± 0.014 mg/L in the patient group and 0.082 ± 0.018 mg/L in the control group. The patients showed significantly high S-100B protein levels compared with healthy controls (P < 0.001).

Conclusion

Our data suggest that increased S-100B protein levels in the serum potentially indicate neuronal damage in the brains of children with epilepsy.

A Pathophysiological Approach To Current Biomarkers

Biomarkers are necessary for screening and diagnosing numerous diseases, predicting the prognosis of patients, and following-up treatment and the course of the patient. Everyday new biomarkers are being used in clinics for these purposes. This section will discuss the physiological roles of the various current biomarkers in a healthy person and the pathophysiological mechanisms underlying the release of these biomarkers. This chapter aims to gain a new perspective for evaluating and interpreting the most current biomarkers.

Prognostic properties of the association between the S‑100B protein levels and the mean cerebral blood flow velocity in patients diagnosed with severe traumatic brain injury

Craniocerebral injury (CBI) is tissue damage caused by a sudden mechanical force. CBI can result in neurological, neuropsychological and psychiatric dysfunctions. Currently, the severity of CBI is assessed using the Glasgow Coma Scale, brain perfusion pressure measurements, transcranial Doppler tests and biochemical markers. This study aimed to determine the applicability of the S-100B protein levels and the time-averaged mean maximum cerebral blood flow velocity (V_mean) as a means of predicting the treatment outcomes of CBI in the first 4 days of hospitalization. The results validated the standard reference ranges previously proposed for the concentration of S-100B (0.05-0.23 µg/l) and the mean of cerebral blood flow velocity (30.9 to 74.1 cm/sec). The following stratification scheme was used to predict the success of treatment: Patients with a Glasgow Outcome Scale (GOS) score ≥4 or GOS <4 were stratified into ‘favorable’ and ‘unfavorable’ groups, respectively. The favorable group showed relatively constant levels of the S-100B protein close to the normal range and exhibited an increase in V_mean, but this was still within the normal range. The unfavorable group exhibited a high level of S-100B protein and increased V_mean outside of the normal ranges. The changes in the levels of S-100B in the unfavorable and favorable groups were -0.03 and -0.006 mg/l/h, respectively. Furthermore, the rate of decrease in the V_mean value in the unfavorable and favorable groups were -0.26 and -0.18 cm/sec/h, respectively. This study showed that constant levels of S-100B protein, even slightly above the normal range, associated with an increase in V_mean was indicative of a positive therapeutic outcome. However, additional research is required to obtain the appropriate statistical strength required for clinical practice.

Arundic Acid (ONO-2506) Attenuates Neuroinflammation and Prevents Motor Impairment in Rats with Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is a severe stroke subtype caused by the rupture of blood vessels within the brain. Increased levels of S100B protein may contribute to neuroinflammation after ICH through activation of astrocytes and resident microglia, with the consequent production of proinflammatory cytokines and reactive oxygen species (ROS). Inhibition of astrocytic synthesis of S100B by arundic acid (AA) has shown beneficial effects in experimental central nervous system disorders. In present study, we administered AA in a collagenase-induced ICH rodent model in order to evaluate its effects on neurological deficits, S100B levels, astrocytic activation, inflammatory, and oxidative parameters. Rats underwent stereotactic surgery for injection of collagenase in the left striatum and AA (2 μg/μl; weight × 0.005) or vehicle in the left lateral ventricle. Neurological deficits were evaluated by the Ladder rung walking and Grip strength tests. Striatal S100B, astrogliosis, and microglial activation were assessed by immunofluorescence analysis. Striatal levels of interleukin 1β (IL-1β) and tumor necrosis factor α (TNF-α) were measured by ELISA, and the ROS production was analyzed by dichlorofluorescein (DCF) oxidation. AA treatment prevented motor dysfunction, reduced S100B levels, astrogliosis, and microglial activation in the damaged striatum, thus decreasing the release of proinflammatory cytokines IL-1β and TNF-α, as well as ROS production. Taken together, present results suggest that AA could be a pharmacological tool to prevent the harmful effects of increased S100B, attenuating neuroinflammation and secondary brain damage after ICH.

S100B Maternal Blood Levels in Gestational Diabetes Mellitus Are Birthweight, Gender and Delivery Mode Dependent

Gestational Diabetes Mellitus (GDM) is one of the main causes of perinatal mortality/morbidity. Today, a parameter offering useful information on fetal central nervous system (CNS) development/damage is eagerly awaited. We investigated the role of brain-protein S100B in the maternal blood of GDM pregnancies by means of a prospective case-control study in 646 pregnancies (GDM: n = 106; controls: n = 530). Maternal blood samples for S100B measurement were collected at four monitoring time-points from 24 weeks of gestation to term. Data was corrected for gender and delivery mode and correlated with gestational age and weight at birth. Results showed higher (p < 0.05) S100B from 24 to 32 weeks and at term in GDM fetuses than controls. Higher (p < 0.05) S100B was observed in GDM male new-borns than in females from 24 to 32 weeks and at term, in GDM cases delivering vaginally than by caesarean section. Finally, S100B positively correlated with gestational age and weight at birth (R = 0.27; R = 0.37, respectively; p < 0.01). The present findings show the usefulness of S100B in CNS to monitor high-risk pregnancies during perinatal standard-of-care procedures. The results suggest that further investigations into its potential role as an early marker of CNS growth/damage in GDM population are needed.

The Value of the Biomarkers Neuron-Specific Enolase and S100 Calcium-Binding Protein for Prediction of Mortality in Children Resuscitated After Cardiac Arrest

The aim of the present study was to assess the ability of the biomarkers neuron-specific enolase (NSE) and S100 calcium-binding protein b (S100b) to predict 30 day mortality in children resuscitated from cardiac arrest (CA). It was a prospective observational study at a single tertiary heart centre. Consecutive children were admitted after resuscitated in-hospital and out-of-hospital CA. Levels of NSE and S100b were analyzed from 12 to 24 hours, from 24 to 48 hours, and from 48 to 72 hours after admission. The primary endpoint was 30-day mortality. Differences in biomarker levels between survivors and non-survivors were analyzed with the Mann-Whitney U test. Receiver operating characteristics (ROC) curves were applied to assess the predictive ability of the biomarkers and the areas under the ROC curves (AUC) were presented. A total of 32 resuscitated CA patients were included, and 12 (38%) patients died within 30 days after resuscitation. We observed significantly higher levels of NSE and S100b in non-survivors compared to survivors at all timepoints from 12 to 72 hours after CA. NSE achieved AUCs from 0.91-0.98 for prediction of 30 day mortality, whereas S100b achieved AUCs from 0.93-0.94. An NSE cut-off of 61 μg/L sampled between 12-24 hours from admission achieved a sensitivity of 80% and a specificity of 100% for prediction of 30 day mortality. In children resuscitated from CA, the biomarkers NSE and S100b appear to be solid predictors of mortality after 30 days.

Do Naturally Occurring Antioxidants Protect Against Neurodegeneration of the Dopaminergic System? A Systematic Revision in Animal Models of Parkinson's Disease

Parkinson's disease (PD) is the second most common neurodegenerative disease and is characterized by a significant decrease in dopamine levels, caused by progressive degeneration of the dopaminergic neurons in the nigrostriatal pathway. Multiple mechanisms have been implicated in its pathogenesis, including oxidative stress, neuroinflammation, protein aggregation, mitochondrial dysfunction, insufficient support for neurotrophic factors and cell apoptosis. The absence of treatments capable of slowing or stopping the progression of PD has increased the interest in the natural antioxidant substances present in the diet, since they have multiple beneficial properties and it is possible that they can influence the mechanisms responsible for the dysfunction and death of dopaminergic neurons. Thus, the purpose of this systematic review is to analyze the results obtained in a set of studies carried out in the last years, which describe the neuroprotective, antioxidant and regenerative functions of some naturally occurring antioxidants in experimental models of PD. The results show that the exogenous no enzymatic antioxidants can significantly modify the biochemical and behavioral mechanisms that contribute to the pathophysiology of Parkinsonism in experimental animals. Therefore, it is possible that they may contribute to effective neuroprotection by providing a significant improvement in neuropathological markers. In conclusion, the results of this review suggest that exogenous antioxidants can be promising therapeutic candidates for the prevention and treatment of PD.

The Potential Roles of Glial Cells in the Neuropathogenesis of Cerebral Malaria

Cerebral malaria (CM) is a severe neurological complication of malaria caused by the Plasmodium falciparum parasite. It is one of the leading causes of death in children under 5 years of age in Sub-Saharan Africa. CM is associated with blood-brain barrier disruption and long-term neurological sequelae in survivors of CM. Despite the vast amount of research on cerebral malaria, the cause of neurological sequelae observed in CM patients is poorly understood. In this article, the potential roles of glial cells, astrocytes, and microglia, in cerebral malaria pathogenesis are reviewed. The possible mechanisms by which glial cells contribute to neurological damage in CM patients are also examined.

Astrocytes in Down Syndrome Across the Lifespan

Down Syndrome (DS) is the most common genetic cause of intellectual disability in which delays and impairments in brain development and function lead to neurological and cognitive phenotypes. Traditionally, a neurocentric approach, focusing on neurons and their connectivity, has been applied to understanding the mechanisms involved in DS brain pathophysiology with an emphasis on how triplication of chromosome 21 leads to alterations in neuronal survival and homeostasis, synaptogenesis, brain circuit development, and neurodegeneration. However, recent studies have drawn attention to the role of non-neuronal cells, especially astrocytes, in DS. Astrocytes comprise a large proportion of cells in the central nervous system (CNS) and are critical for brain development, homeostasis, and function. As triplication of chromosome 21 occurs in all cells in DS (with the exception of mosaic DS), a deeper understanding of the impact of trisomy 21 on astrocytes in DS pathophysiology is warranted and will likely be necessary for determining how specific brain alterations and neurological phenotypes emerge and progress in DS. Here, we review the current understanding of the role of astrocytes in DS, and discuss how specific perturbations in this cell type can impact the brain across the lifespan from early brain development to adult stages. Finally, we highlight how targeting, modifying, and/or correcting specific molecular pathways and properties of astrocytes in DS may provide an effective therapeutic direction given the important role of astrocytes in regulating brain development and function.

Astroglial Hemichannels and Pannexons: The Hidden Link between Maternal Inflammation and Neurological Disorders

Maternal inflammation during pregnancy causes later-in-life alterations of the offspring’s brain structure and function. These abnormalities increase the risk of developing several psychiatric and neurological disorders, including schizophrenia, intellectual disability, bipolar disorder, autism spectrum disorder, microcephaly, and cerebral palsy. Here, we discuss how astrocytes might contribute to postnatal brain dysfunction following maternal inflammation, focusing on the signaling mediated by two families of plasma membrane channels: hemi-channels and pannexons. [Ca²⁺]_i imbalance linked to the opening of astrocytic hemichannels and pannexons could disturb essential functions that sustain astrocytic survival and astrocyte-to-neuron support, including energy and redox homeostasis, uptake of K⁺ and glutamate, and the delivery of neurotrophic factors and energy-rich metabolites. Both phenomena could make neurons more susceptible to the harmful effect of prenatal inflammation and the experience of a second immune challenge during adulthood. On the other hand, maternal inflammation could cause excitotoxicity by producing the release of high amounts of gliotransmitters via astrocytic hemichannels/pannexons, eliciting further neuronal damage. Understanding how hemichannels and pannexons participate in maternal inflammation-induced brain abnormalities could be critical for developing pharmacological therapies against neurological disorders observed in the offspring.

ECP Overexpression in T Cells and Exosomes Induces IFN-γ Production and Tissue Inflammation

Objective

T cells play a critical role in the pathogenesis of systemic lupus erythematosus (SLE). Serum‐derived exosomes are increased in SLE patients and are correlated with disease severity. This study was undertaken to investigate whether T cell–derived exosomal proteins play a role in SLE pathogenesis.

Methods

We characterized proteins in T cell–derived exosomes from SLE patients and healthy controls by MACSPlex exosome analysis and proteomics. To study the potential pathogenic functions of the exosomal protein identified, we generated and characterized T cell–specific transgenic mice that overexpressed that protein in T cells.

Results

We identified eosinophil cationic protein (ECP, also called human RNase III) as overexpressed in SLE T cell–derived exosomes. T cell–specific ECP–transgenic mice (n = 5 per group) displayed early induction of serum interferon‐γ (IFNγ) levels (P = 0.062) and inflammation of multiple tissue types. Older T cell–specific ECP–transgenic mice (n = 3 per group) also displayed an increase in follicular helper T cell and plasma B cell numbers, and in autoantibody levels (P < 0.01). Single‐cell RNA sequencing showed the induction of IFNγ messenger RNA (P = 2.2 × 10^‐13) and inflammatory pathways in ECP‐transgenic mouse T cells. Notably, adoptively transferred ECP‐containing exosomes stimulated serum autoantibody levels (P < 0.01) and tissue IFNγ levels in the recipient mice (n = 3 per group). The transferred exosomes infiltrated into multiple tissues of the recipient mice, resulting in hepatitis, nephritis, and arthritis.

Conclusion

Our findings indicate that ECP overexpression in T cells or T cell–derived exosomes may be a biomarker and pathogenic factor for nephritis, hepatitis, and arthritis associated with SLE.

Cerebrospinal Fluid C18 Ceramide Associates with Markers of Alzheimer's Disease and Inflammation at the Pre- and Early Stages of Dementia

Background:

Understanding how dysregulation in lipid metabolism relates to the severity of Alzheimer‘s disease (AD) pathology might be critical in developing effective treatments.

Objective:

To identify lipid species in cerebrospinal fluid (CSF) associated with signature AD pathology and to explore their relationships with measures reflecting AD-related processes (neurodegeneration, inflammation, deficits in verbal episodic memory) among subjects at the pre- and early symptomatic stages of dementia.

Methods:

A total of 60 subjects that had been referred to an Icelandic memory clinic cohort were classified as having CSF AD (n = 34) or non-AD (n = 26) pathology profiles. Untargeted CSF lipidomic analysis was performed using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS) for the detection of mass-to-charge ratio (m/z) features. CSF proteins reflecting neurodegeneration (neurofilament light [NFL]) and inflammation (chitinase-3-like protein 1 [YKL-40], S100 calcium-binding protein B [S100B], glial fibrillary acidic protein [GFAP]) were also measured. Rey Auditory Verbal Learning (RAVLT) and Story tests were used for the assessment of verbal episodic memory.

Results:

Eight out of 1008 features were identified as best distinguishing between the CSF profile groups. Of those, only the annotation of the m/z feature assigned to lipid species C18 ceramide was confirmed with a high confidence. Multiple regression analyses, adjusted for age, gender, and education, demonstrated significant associations of CSF core AD markers (Aβ₄₂: st.β= –0.36, p = 0.007; T-tau: st.β= 0.41, p = 0.005) and inflammatory marker S100B (st.β= 0.51, p = 0.001) with C18 ceramide levels.

Conclusion:

Higher levels of C18 ceramide associated with increased AD pathology and inflammation, suggesting its potential value as a therapeutic target.

Circulating neurotrophins and hemostatic risk factors of atherothrombotic cardiovascular disease at baseline and during sympathetic challenge: the SABPA study

Sympathetic activation may trigger acute coronary syndromes. We examined the relation between circulating neurotrophic factors and hemostatic risk factors of atherothrombotic cardiovascular disease at baseline and in response to acute mental stress to establish a brain-heart link. In 409 black and white South Africans, brain-derived neurotrophic factor (BDNF) and fibrinolytic measures were assessed at baseline. Glial cell-derived neurotrophic factor (GDNF), S100 calcium-binding protein (S100B), von Willebrand factor (VWF), fibrinogen and D-dimer were assessed at baseline and 10 min after the Stroop test. Neurotrophins were regressed on hemostatic measures adjusting for demographics, comorbidities, cardiometabolic factors and health behaviors. Higher baseline BDNF was associated with greater stress-induced increase in fibrinogen (p = 0.003) and lower D-dimer increase (p = 0.016). Higher baseline S100B was significantly associated with higher baseline VWF (p = 0.031) and lower fibrinogen increase (p = 0.048). Lower baseline GDNF was associated with higher baseline VWF (p = 0.035) but lower VWF increase (p = 0.001). Greater GDNF (p = 0.006) and S100B (p = 0.042) increases were associated with lower VWF increase. All associations showed small-to-moderate effect sizes. Neurotrophins and fibrinolytic factors showed no significant associations. The findings support the existence of a peripheral neurothrophin-hemostasis interaction of small-to-moderate clinical relevance. The implications for atherothrombotic cardiovascular disease need further exploration.

[Anti-oxidants in astrocytes as target of neuroprotection for Parkinson's disease]

Recently, it has been reported that dysfunction of astrocytes is involved vulnerability of neuronal cells in several neurological disorders. Glutathione (GSH) is the most abundant intrinsic antioxidant in the central nervous system, and its substrate cysteine is readily becomes the oxidized dimeric cystine. Since neurons lack a cystine transport system, neuronal GSH synthesis depends on cystine uptake via the cystine/glutamate exchange transporter (xCT), GSH synthesis and release in/from surrounding astrocytes. The expression and release of the zinc-binding protein metallothionein (MT) in astrocytes, which is a strong antioxidant, is induced and exerts neuroprotective in the case of dopaminergic neuronal damage. In addition, the transcription factor Nrf2 induces expression of MT-1 and GSH related molecules. We previously revealed that several antiepileptic drugs, serotonin 5-HT1A receptor agonists, plant-derived chemicals (phytochemicals) increased xCT expression, Nrf2 activation, GSH or MT expression and release in/from astrocytes, and exerted a neuroprotective effect against dopaminergic neurodegeneration in Parkinson's disease model. Our serial studies on neuroprotection via antioxidant defense mechanism of astrocytes have found three target molecular systems of astrocytes for neuroprotection: (1) xCT-GSH synthetic system, (2) Nrf2 system and (3) 5-HT1A receptor-Nrf2-MT system, 5-HT1A-S100β system. In this article, possible neuroprotective strategy for Parkinson's disease has been reviewed targeting antioxidative molecules in astrocytes.

Targeting S100B Protein as a Surrogate Biomarker and its Role in Various Neurological Disorders

Neurological disorders (ND) are the central nervous system (CNS) related complications originated by enhanced oxidative stress, mitochondrial failure and overexpression of proteins like S100B. S100B is a helix-loop-helix protein with the calcium-binding domain associated with various neurological disorders through activation of the MAPK pathway, increased NF-kB expression resulting in cell survival, proliferation and gene up-regulation. S100B protein plays a crucial role in Alzheimer's disease, Parkinson's disease, multiple sclerosis, Schizophrenia and epilepsy because the high expression of this protein directly targets astrocytes and promotes neuroinflammation. Under stressful conditions, S100B produces toxic effects mediated through receptor for advanced glycation end products (AGE) binding. S100B also mediates neuroprotection, minimizes microgliosis and reduces the expression of tumor necrosis factor (TNF-alpha) but that are concentration- dependent mechanisms. Increased level of S100B is useful for assessing the release of inflammatory markers, nitric oxide and excitotoxicity dependent neuronal loss. The present review summarizes the role of S100B in various neurological disorders and potential therapeutic measures to reduce the prevalence of neurological disorders.

Chronic stress followed by social isolation promotes depressive-like behaviour, alters microglial and astrocyte biology and reduces hippocampal neurogenesis in male mice

Unpredictable chronic mild stress (UCMS) is one of the most commonly used, robust and translatable models for studying the neurobiological basis of major depression. Although the model currently has multiple advantages, it does not entirely follow the trajectory of the disorder, whereby depressive symptomology can often present months after exposure to stress. Furthermore, patients with depression are more likely to withdraw in response to their stressful experience, or as a symptom of their depression, and, in turn, this withdrawal/isolation can further exacerbate the stressful experience and the depressive symptomology. Therefore, we investigated the effect(s) of 6 weeks of UCMS followed by another 6 weeks of social isolation (referred to as UCMSI), on behaviour, corticosterone stress responsivity, immune system functioning, and hippocampal neurogenesis, in young adult male mice. We found that UCMSI induced several behavioural changes resembling depression but did not induce peripheral inflammation. However, UCMSI animals showed increased microglial activation in the ventral dentate gyrus (DG) of the hippocampus and astrocyte activation in both the dorsal and ventral DG, with increased GFAP-positive cell immunoreactivity, GFAP-positive cell hypertrophy and process extension, and increased s100β-positive cell density. Moreover, UCMSI animals had significantly reduced neurogenesis in the DG and reduced levels of peripheral vascular endothelial growth factor (VEGF) - a trophic factor produced by astrocytes and that stimulates neurogenesis. Finally, UCMSI mice also had normal baseline corticosterone levels but a smaller increase in corticosterone following acute stress, that is, the Porsolt Swim Test. Our work gives clinically relevant insights into the role that microglial and astrocyte functioning, and hippocampal neurogenesis may play in the context of stress, social isolation and depression, offering a potentially new avenue for therapeutic target.

Effects of S100B neutralization on the long-term cognitive impairment and neuroinflammatory response in an animal model of sepsis

The nervous system is one of the first systems to be affected during sepsis. Sepsis not only has a high risk of mortality, but could also lead to cerebral dysfunction and cognitive impairment in long-term survival patients. The receptor for advanced glycation end products (RAGE) can interact with several ligands, and its activation triggers a series of cell signaling events, resulting in the hyperinflammatory condition related to sepsis. Recent studies show that elevated levels of S100B (RAGE ligand) are associated with the pathophysiology of neurodegenerative disorders. They also participate in inflammatory brain diseases and may lead to an increased activation of microglia and astrocytes, leading to neuronal death. This study aimed to determine the effect of S100B inhibition on the neuroinflammatory response in sepsis. Sepsis was induced in Wistar rats by cecal ligation and perforation (CLP). There were three groups: Sham, CLP, and CLP +10 μg/kg of monoclonal antibody (Anti-S100B) administered intracerebroventricularly. The animals were killed 30 days after sepsis following behavioral evaluation by open field, novel object recognition, and splash test. The hippocampus, prefrontal cortex, and amydgala were used for the determination of S100B and RAGE proteins by western blotting and for the evaluation of cytokine levels and verification of the number of microglial cells by immunohistochemistry. On day 30, both the Sham and CLP + anti-S100B groups were capable of recovering the habitual memory in the open field task. Regarding novel object recognition, Sham and CLP + anti-S100B groups increased the recognition index during the test session in comparison to the training session. There was a significant increase in the time of grooming in CLP + anti-S100B in comparison to the CLP group. There was a modulation of cytokine levels and immunohistochemistry showed that the CLP + anti-S100B group had a decrease in the number of microglial cells only in the hippocampus. These results helped to understand the role of S100B protein in the pathophysiology of sepsis-associated encephalopathy and could be helpful to further experimental studies regarding this subject.

S100B Impairs Oligodendrogenesis and Myelin Repair Following Demyelination Through RAGE Engagement

Increased expression of S100B and its specific receptor for advanced glycation end products (RAGE) has been described in patients with multiple sclerosis (MS), being associated with an active demyelinating process. We previously showed that a direct neutralization of S100B reduces lysophosphatidylcholine (LPC)-induced demyelination and inflammation using an ex vivo demyelinating model. However, whether S100B actions occur through RAGE and how oligodendrogenesis and remyelination are affected are not clarified. To evaluate the role of the S100B–RAGE axis in the course of a demyelinating insult, organotypic cerebellar slice cultures (OCSC) were demyelinated with LPC in the presence or absence of RAGE antagonist FPS-ZM1. Then, we explored the effects of the S100B–RAGE axis inhibition on glia reactivity and inflammation, myelination and neuronal integrity, and on oligodendrogenesis and remyelination. In the present study, we confirmed that LPC-induced demyelination increased S100B and RAGE expression, while RAGE antagonist FPS-ZM1 markedly reduced their content and altered RAGE cellular localization. Furthermore, FPS-ZM1 prevented LPC-induced microgliosis and astrogliosis, as well as NF-κB activation and pro-inflammatory cytokine gene expression. In addition, RAGE antagonist reduced LPC-induced demyelination having a beneficial effect on axonal and synaptic protein preservation. We have also observed that RAGE engagement is needed for LPC-induced oligodendrocyte (OL) maturation arrest and loss of mature myelinating OL, with these phenomena being prevented by FPS-ZM1. Our data suggest that increased levels of mature OL in the presence of FPS-ZM1 are related to increased expression of microRNAs (miRs) associated with OL differentiation and remyelination, such as miR-23a, miR-219a, and miR-338, which are defective upon LPC incubation. Finally, our electron microscopy data show that inhibition of the S100B–RAGE axis prevents axonal damage and myelin loss, in parallel with enhanced functional remyelination, as observed by the presence of thinner myelin sheaths when compared with Control. Overall, our data implicate the S100B–RAGE axis in the extent of myelin and neuronal damage, as well as in the inflammatory response that follows a demyelinating insult. Thus, prevention of RAGE engagement may represent a novel strategy for promoting not only inflammatory reduction but also neuronal and myelin preservation and/or remyelination, improving recovery in a demyelinating condition as MS.

Arundic Acid (ONO-2506), an Inhibitor of S100B Protein Synthesis, Prevents Neurological Deficits and Brain Tissue Damage Following Intracerebral Hemorrhage in Male Wistar Rats

Stroke is one of the leading causes of mortality and neurological morbidity. Intracerebral hemorrhage (ICH) has the poorest prognosis among all stroke subtypes and no treatment has been effective in improving outcomes. Following ICH, the observed high levels of S100B protein have been associated with worsening of injury and neurological deficits. Arundic acid (AA) exerts neuroprotective effects through inhibition of astrocytic synthesis of S100B in some models of experimental brain injury; however, it has not been studied in ICH. The aim of this study was to evaluate the effects of intracerebroventricular (ICV) administration of AA in male Wistar rats submitted to ICH model assessing the following variables: reactive astrogliosis, S100B levels, antioxidant defenses, cell death, lesion extension and neurological function. Firstly, AA was injected at different doses (0.02, 0.2, 2 and 20 μg/μl) in the left lateral ventricle in order to observe which dose would decrease GFAP and S100B striatal levels in non-injured rats. Following determination of the effective dose, ICH damage was induced by IV-S collagenase intrastrial injection and 2 μg/μl AA was injected through ICV route immediately before injury. AA treatment prevented ICH-induced neurological deficits and tissue damage, inhibited excessive astrocytic activation and cellular apoptosis, reduced peripheral and central S100B levels (in striatum, serum and cerebrospinal fluid), improved neuronal survival and enhanced the antioxidant defences after injury. Altogether, these results suggest that S100B is a viable target for treating ICH and highlight AA as an interesting strategy for improving neurological outcome after experimental brain hemorrhage.

Potential Astrocytic Receptors and Transporters in the Pathogenesis of Alzheimer's Disease

Alzheimer's disease (AD) is the most common cause of dementia and is characterized by the progressive loss of memory and cognition in the aging population. However, the etiology of and therapies for AD remain far from understood. Astrocytes, the most abundant neuroglia in the brain, have recently aroused substantial concern due to their involvement in synaptotoxicity, amyloidosis, neuroinflammation, and oxidative stress. In this review, we summarize the candidate molecules of astrocytes, especially receptors and transporters, that may be involved in AD pathogenesis. These molecules include excitatory amino acid transporters (EAATs), metabotropic glutamate receptor 5 (mGluR5), the adenosine 2A receptor (A2AR), the α7-nicotinic acetylcholine receptor (α7-nAChR), the calcium-sensing receptor (CaSR), S100β, and cannabinoid receptors. We describe the characteristics of these molecules and the neurological and pharmacological underpinnings of these molecules in AD. Among these molecules, EAATs, A2AR, and mGluR5 are strongly related to glutamate-mediated synaptotoxicity and are involved in glutamate transmission or the clearance of extrasynaptic glutamate in the AD brain. The α7-nAChR, CaSR, and mGluR5 are receptors of Aβ and can induce a plethora of toxic effects, such as the production of excess Aβ, synaptotoxicity, and NO production triggered by changes in intracellular calcium signaling. Antagonists or positive allosteric modulators of these receptors can repair cognitive ability and modify neurobiological changes. Moreover, blocking S100β or activating cannabinoid receptors reduces neuroinflammation, oxidative stress, and reactive astrogliosis. Thus, targeting these molecules might provide alternative approaches for treating AD.

The single intravenous administration of methylene blue after traumatic brain injury diminishes neurological deficit, blood-brain barrier disruption and decrease in the expression of S100 protein in rats

The protective effect of methylene blue (MB) was investigated on the model of focal one-sided traumatic brain injury (TBI) of the sensorimotor cortex region from 1 to 7 days after the injury. TBI caused a reliable disruption of the functions of the limbs contralateral to injury focus, an increase in the expression of S100 protein and blood-brain barrier (BBB) permeability in the ipsilateral hemisphere. The single intravenous injection of MB (1 mg/kg body weight) 30 min after TBI significantly reduced the limb function impairment as well as a TBI-induced increase in the expression of inflammatory marker S100 protein, and BBB permeability. When modeling inflammation in vitro, MB was found to protect cultured neurons from the toxic effects of lipopolysaccharide. In conclusion, the preservation of blood-brain barrier and a decrease in the expression of S100 protein may be an important mechanism by means of which MB improves neurological outcome. Our data demonstrate that MB can be a very promising pharmacological compound with neuroprotective properties for TBI treatment.

Early predictors of perinatal brain damage: the role of neurobiomarkers

The early detection of perinatal brain damage in preterm and term newborns (i.e. intraventricular hemorrhage, periventricular leukomalacia and perinatal asphyxia) still constitute an unsolved issue. To date, despite technological improvement in standard perinatal monitoring procedures, decreasing the incidence of perinatal mortality, the perinatal morbidity pattern has a flat trend. Against this background, the measurement of brain constituents could be particularly useful in the early detection of cases at risk for short-/long-term brain injury. On this scenario, the main European and US international health-care institutions promoted perinatal clinical and experimental neuroprotection research projects aimed at validating and including a panel of biomarkers in the clinical guidelines. Although this is a promising attempt, there are several limitations that do not allow biomarkers to be included in standard monitoring procedures. The main limitations are: (i) the heterogeneity of neurological complications in the perinatal period, (ii) the small cohort sizes, (iii) the lack of multicenter investigations, (iv) the different techniques for neurobiomarkers assessment, (iv) the lack of consensus for the validation of assays in biological fluids such as urine and saliva, and (v), the lack of reference curves according to measurement technique and biological fluid. In the present review we offer an up-to-date overview of the most promising developments in the use of biomarkers in the perinatal period such as calcium binding proteins (S100B protein), vasoactive agents (adrenomedullin), brain biomarkers (activin A, neuron specific enolase, glial fibrillary acidic protein, ubiquitin carboxyl-terminal hydrolase-L1) and oxidative stress markers.

The effect of obstructive sleep apnea syndrome on serum S100B and NSE levels: a systematic review and meta-analysis of observational studies

Background

Obstructive sleep apnea syndrome (OSAS) is a common disorder that is accompanied by structural brain changes. This meta-analysis aimed to evaluate the effect of OSAS on the serum levels of astrocytic protein (S100B) and neuron-specific enolase (NSE) in observational studies.

Methods

A comprehensive search was performed in the PubMed/Medline, Web of Science, Scopus, ScienceDirect, and Cochrane Library databases to assess the serum level of S100B and/or NSE in patients with OSAS and/or controls. The quality of the study was evaluated by the Newcastle-Ottawa Scale (NOS). A random-effects model was performed using RevMan 5.3 with the mean difference (MD) and 95% confidence intervals (CIs).

Results

Out of 63 studies found in the mentioned databases and one identified by a manual search, nine studies were included and analyzed in this meta-analysis (three cross-sectional and six case-control studies). The analysis showed that the S100B [MD = 53.58 pg/ml, 95%CI: 1.81, 105.35; P = 0.04] and NSE levels [MD = 3.78 ng/ml, 95%CI: 2.07, 5.48; P < 0.0001] were significantly higher in patients than the controls. However, there were no significant differences between the S100B [MD = -28.00 pg/ml, 95%CI: − 79.48, 23.47; P = 0.29] and NSE levels [MD = 0.49 ng/ml, 95%CI: − 0.82, 1.80; P = 0.46].

Conclusions

This meta-analysis found elevated serum S100B and NSE levels in OSAS patients compared to the controls, which suggests that these markers may be used as peripheral indicators of brain damage in OSAS.

Administration of ONO-2506 suppresses neuropathic pain after spinal cord injury by inhibition of astrocytic activation

BACKGROUND CONTEXT

Spinal cord injury (SCI) results in not only motor dysfunction but also chronic neuropathic pain. Allodynia, an abnormal sensation that evokes pain against non-noxious stimuli, is a major symptom of post-SCI neuropathic pain. Astrocytic activation is a cause of post-SCI neuropathic pain and is considered a key treatment target. However, no effective treatment for these problems is available to date. ONO-2506 is a novel agent that suppresses astrocytic activation by inhibition of S100B production from astrocytes. Recently, it has been demonstrated that ONO-2506 inhibits secondary injury and improves motor function after SCI.

PURPOSE

This study aimed to investigate the effect of ONO-2506 on post-SCI neuropathic pain.

STUDY DESIGN

Animal study of a rat model of spinal cord contusion.

METHODS

A total of 22 male Sprague-Dawley rats aged 6 weeks were used. Incomplete SCI was created at T10 level. Animals were divided into two groups: Saline group and ONO-2506 group. Nine animals in each group were finally included for this study. Intraperitoneal administration of ONO-2506 (20 mg/kg) or saline was continued daily for 1 week following SCI. Recovery of hind limb motor function was assessed using the Basso, Beattie, and Bresnahan (BBB) score. Mechanical and thermal allodynia of hind paws were evaluated by the withdrawal threshold using a von Frey filament and the withdrawal latency using the plantar test device. At 6 weeks after SCI, sagittal sections at the injured site and axial sections at L 4/5 were evaluated by fluorescent immunohistochemistry staining using S100B and glial fibrillary acidic protein (GFAP) antibodies.

RESULTS

The improvement course of BBB scores was similar between the two groups. However, the withdrawal thresholds for mechanical stimuli and the withdrawal latency for thermal stimuli were significantly higher in the ONO-2506 group than in the Saline group over 6 weeks after SCI. The histologic assessments at the injured site demonstrated a significant reduction in the cross-sectional area of the cysts and a high fluorescence intensity area of S100B and GFAP in the ONO-2506 group. By correlation analysis, a high absolute value of the correlation coefficient was confirmed between the intensity of S100B expression at the injured site and the allodynia severity.

CONCLUSION

Administration of ONO-2506 attenuated post-SCI neuropathic pain in a rat model of incomplete SCI. Histologic results support that the inhibition of S100B production and subsequent suppression of astrocytic activation contributed to the reduction in neuropathic pain.

Arterial stiffness induced by carotid calcification leads to cerebral gliosis mediated by oxidative stress

BACKGROUND

Arterial stiffness is a risk factor for cognitive decline and dementia. However, its precise effects on the brain remain unexplored. Using a mouse model of carotid stiffness, we investigated its effect on glial activation and oxidative stress.

METHODS

Arterial stiffness was induced by the application of calcium chloride to the adventitial region of the right carotid. Superoxide anion production, NADPH activity and levels, as well as glial activation were examined with immunohistochemical and biochemical approaches, 2-week postcalcification. Antioxidant treatment was done with Tempol (1 mmol/l) administered in the drinking water during 2 weeks.

RESULTS

The current study revealed that arterial stiffness increases the levels of the microglial markers ionized calcium-binding adapter molecule 1 and cluster of differentiation 68 in hippocampus, and of the astrocyte marker, s100 calcium binding protein β in hippocampus and frontal cortex. The cerebral inflammatory effects of arterial stiffness were specific to the brain and not due to systemic inflammation. Treatment with Tempol prevented the increase in superoxide anion in mice with carotid stiffness and attenuated the activation of microglia and astrocytes in the hippocampus. To determine whether the increased oxidative stress derives from NADPH oxidase, superoxide anion production was assessed by incubating brain tissue in the presence of gp91ds-tat, a selective NADPH oxidase 2 inhibitor. This peptide inhibited superoxide anion production to a greater extent in the brains of mice with carotid calcification compared with controls.

CONCLUSION

Carotid calcification leads to cerebral gliosis mediated by oxidative stress. Correcting arterial stiffness could offer a novel paradigm to protect the brain in populations where stiffness is prominent.

L-alpha-aminoadipic acid restricts dopaminergic neurodegeneration and motor deficits in an inflammatory model of Parkinson's disease in male rats

Neuroinflammation is a contributory factor underlying the progressive nature of dopaminergic neuronal loss within the substantia nigra (SN) of Parkinson's disease (PD) patients, albeit the role of astrocytes in this process has been relatively unexplored to date. Here, we aimed to investigate the impact of midbrain astrocytic dysfunction in the pathophysiology of intra-nigral lipopolysaccharide (LPS)-induced experimental Parkinsonism in male Wistar rats via simultaneous co-injection of the astrocytic toxin L-alpha-aminoadipic acid (L-AAA). Simultaneous intra-nigral injection of L-AAA attenuated the LPS-induced loss of tyrosine hydroxylase-positive (TH⁺ ) dopamine neurons in the SNpc and suppressed the affiliated degeneration of TH⁺ dopaminergic nerve terminals in the striatum. L-AAA also repressed LPS-induced nigrostriatal dopamine depletion and provided partial protection against ensuing motor dysfunction. L-AAA abrogated intra-nigral LPS-induced glial fibrillary acidic protein-positive (GFAP⁺ ) reactive astrogliosis and attenuated the LPS-mediated increases in nigral S100β expression levels in a time-dependent manner, findings which were associated with reduced ionized calcium binding adaptor molecule 1-positive (Iba1⁺ ) microgliosis, thus indicating a role for reactive astrocytes in sustaining microglial activation at the interface of dopaminergic neuronal loss in response to an immune stimulus. These results indicate that midbrain astrocytic dysfunction restricts the development of dopaminergic neuropathology and motor impairments in rats, highlighting reactive astrocytes as key contributors in inflammatory associated degeneration of the nigrostriatal tract.

The Effects of Astrocyte and Oligodendrocyte Lineage Cell Interaction on White Matter Injury under Chronic Cerebral Hypoperfusion

Oligodendrocytes (OLGs) differentiate from oligodendrocyte-precursor-cells (OPCs) for myelination in white matter. This differentiation is maintained by cell-cell interactions through trophic factors such as brain-derived-neurotrophic-factor (BDNF). However, differentiation is impaired when white matter injury occurs in a chronic cerebral hypoperfusion model. Thus, we examined the effects of the interaction between astrocyte and oligodendrocyte lineage cells on myelination regarding the mechanism of impairment. A microcoil was applied to the bilateral common carotid arteries in male C57BL/6 mice as an in vivo cerebral chronic hypoperfusion model (BCAS model). A nonlethal concentration of CoCl2 was added to the primary cell culture from the postnatal rat cortex and incubated in vitro. White matter injury progressed in the BCAS model as myelin decreased. The numbers of OPCs and astrocytes increased after the operation, whereas that of OLGs decreased at day 28. BDNF continuously decreased until day 28. Differentiation was disrupted under the stressed conditions in the cell culture, but improved after administration of astrocyte-conditioned medium containing BDNF. Astrocytes with BDNF underwent differentiation, but differentiation was impaired under the stressed conditions due to the reduction of BDNF. We examined S100B regarding the mechanism of impairment. S100B is mainly expressed by mature astrocytes, and has neuroprotective and neurotoxic effects inside and outside of cells. GFAP-positive astrocytes increased in the corpus callosum in the BCAS model, whereas the number of mature astrocytes continued to decrease, resulting in reduced BDNF. The reduction in mature astrocytes due to the discharge of S100B in ischemic conditions caused the reduction in BDNF.

Immunity Against Bacterial Infection of the Central Nervous System: An Astrocyte Perspective

Bacterial infection of the central nervous system (CNS) is a severe and life-threatening condition with high mortality, and it may lead to permanent neurological deficits in survivors. Increasing evidence indicates that astrocytes, as the most abundant CNS glial cell population, regulate innate and adaptive immune responses in the CNS under pathological conditions in addition to their role in the maintenance of CNS homeostasis and neuronal function. Following antigen recognition, astrocytes participate in the initiation of innate immune responses, and prompt an adaptive immune response to recruit peripheral immune cells. Investigations have been conducted to understand the immunological role of astrocytes in CNS disease and injury, however, their part in bacterial infections of the CNS has not been fully evaluated. A better understanding will permit the identification of successful therapeutic targets for an improved prognosis and disease outcome.

Brain grey matter volume reduction and anxiety-like behavior in lipopolysaccharide-induced chronic pulmonary inflammation rats: A structural MRI study with histological validation

While there have been multiple fMRI studies into the brain functional changes after acutely stimulated peripheral infection, knowledge for the effect of chronic peripheral infection on whole brain morphology is still quite limited. The present study was designed to investigate the brain structural and emotional changes after peripheral local infection initiated chronic systemic inflammation and the relationship between circulating inflammatory markers and brain grey matter. Specifically, in-vivo T2-weighted MRI was performed on rats with lipopolysaccharide (LPS)-induced chronic pulmonary inflammation (CPI) and those without. Grey matter volume was quantified using diffeomorphic anatomical registration through exponentiated lie (DARTEL) enhanced voxel-based morphometry followed by between-group comparison. Open field experiment was conducted to test the potential anxiety-like behaviors after CPI, along with the ELISA estimated inflammatory markers were correlated to grey matter volume. Guided by image findings, we undertook a focused histological investigation with immunefluorescence and Nissl staining. A widespread decrease of grey matter volume in CPI-model rats was revealed. 8 of the 12 measured inflammatory markers presented differential neuroanatomical correlation patterns with three of the pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) and CRP being the most notable. Lower grey matter volumes in some of the inflammatory markers related regions (amygdala, CA2 and cingulate cortex) were associated with more-severe anxiety-like behaviors. Furthermore, grey matter volumes in amygdala and CA3 were correlated negatively with the expressions of glial proteins (S100β and Nogo-A), while the grey matter volume in hypo-thalamus was changing positively with neural cell area. Overall, the neuroanatomical association patterns and the histopathology underpinning the MRI observations we demonstrated here would probably serve as one explanation for the cerebral and emotional deficits presented in the patients with CPI, which would furthermore yield new insights into the adverse effects the many other systemic inflammation and inflammatory autoimmune diseases would pose on brain morphology.

Vascular cognitive impairment: pathophysiological mechanisms, insights into structural basis, and perspectives in specific treatments

Vascular cognitive impairment (VCI) and vascular dementia are the most common forms of cognitive disorder associated with cerebrovascular disease and related to increased morbidity and mortality among the older population. Growing evidence suggests the contribution of blood-pressure variability, cardiac arrhythmia, hyperactivation of the renin-angiotensin-aldosterone system, endothelial dysfunction, vascular remodeling and stiffness, different angiopathies, neural tissue homeostasis, and systemic metabolic disorders to the pathophysiology of VCI. In this review, we focus on factors contributing to cerebrovascular disease, neurovascular unit alterations, and novel approaches to cognitive improvement in patients with cognitive decline. One of the important factors associated with the neuronal causes of VCI is the S100B protein, which can affect the expression of cytokines in the brain, support homeostasis, and regulate processes of differentiation, repair, and apoptosis of the nervous tissue. Since the pathological basis of VCI is complex and diverse, treatment affecting the mechanisms of cognitive disorders should be developed. The prospective role of a novel complex drug consisting of released-active antibodies to S100 and to endothelial NO synthase in VCI treatment is highlighted.

Advances in developing novel therapeutic strategies for Alzheimer's disease

Alzheimer's Disease (AD), the most prevalent neurodegenerative disease of aging, affects one in eight older Americans. Nearly all drug treatments tested for AD today have failed to show any efficacy. There is a great need for therapies to prevent and/or slow the progression of AD. The major challenge in AD drug development is lack of clarity about the mechanisms underlying AD pathogenesis and pathophysiology. Several studies support the notion that AD is a multifactorial disease. While there is abundant evidence that amyloid plays a role in AD pathogenesis, other mechanisms have been implicated in AD such as tangle formation and spread, dysregulated protein degradation pathways, neuroinflammation, and loss of support by neurotrophic factors. Therefore, current paradigms of AD drug design have been shifted from single target approach (primarily amyloid-centric) to developing drugs targeted at multiple disease aspects, and from treating AD at later stages of disease progression to focusing on preventive strategies at early stages of disease development. Here, we summarize current strategies and new trends of AD drug development, including pre-clinical and clinical trials that target different aspects of disease (mechanism-based versus non-mechanism based, e.g. symptomatic treatments, lifestyle modifications and risk factor management).

Elevated cerebrospinal fluid Galectin-9 is associated with central nervous system immune activation and poor cognitive performance in older HIV-infected individuals

We previously reported that galectin-9 (Gal-9), a soluble lectin with immunomodulatory properties, is elevated in plasma during HIV infection and induces HIV transcription. The link between Gal-9 and compromised neuronal function is becoming increasingly evident; however, the association with neuroHIV remains unknown. We measured Gal-9 levels by ELISA in cerebrospinal fluid (CSF) and plasma of 70 HIV-infected (HIV+) adults stratified by age (older > 40 years and younger < 40 years) either ART suppressed or with detectable CSF HIV RNA, including a subgroup with cognitive assessments, and 18 HIV uninfected (HIV-) controls. Gal-9 tissue expression was compared in necropsy brain specimens from HIV- and HIV+ donors using gene datasets and immunohistochemistry. Among older HIV+ adults, CSF Gal-9 was elevated in the ART suppressed and CSF viremic groups compared to controls, whereas in the younger group, Gal-9 levels were elevated only in the CSF viremic group (p < 0.05). CSF Gal-9 positively correlated with age in all groups (p < 0.05). CSF Gal-9 tracked with CSF HIV RNA irrespective of age (β = 0.33; p < 0.05). Higher CSF Gal-9 in the older viremic HIV+ group correlated with worse neuropsychological test performance scores independently of age and CSF HIV RNA (p < 0.05). Furthermore, CSF Gal-9 directly correlated with myeloid activation (CSF-soluble CD163 and neopterin) in both HIV+ older groups (p < 0.05). Among HIV+ necropsy specimens, Gal-9 expression was increased in select brain regions compared to controls (p < 0.05). Gal-9 may serve as a novel neuroimmuno-modulatory protein that is involved in driving cognitive deficits in those aging with HIV and may be valuable in tracking cognitive abnormalities.

Effects of Oxaliplatin Treatment on the Myenteric Plexus Innervation and Glia in the Murine Distal Colon

Oxaliplatin (platinum-based chemotherapeutic agent) is a first-line treatment of colorectal malignancies; its use associates with peripheral neuropathies and gastrointestinal side effects. These gastrointestinal dysfunctions might be due to toxic effects of oxaliplatin on the intestinal innervation and glia. Male Balb/c mice received intraperitoneal injections of sterile water or oxaliplatin (3 mg/kg/d) triweekly for 2 weeks. Colon tissues were collected for immunohistochemical assessment at day 14. The density of sensory, adrenergic, and cholinergic nerve fibers labeled with calcitonin gene-related peptide (CGRP), tyrosine hydroxylase (TH), and vesicular acetylcholine transporter (VAChT), respectively, was assessed within the myenteric plexus of the distal colon. The number and proportion of excitatory neurons immunoreactive (IR) against choline acetyltransferase (ChAT) were counted, and the density of glial subpopulations was determined by using antibodies specific for glial fibrillary acidic protein (GFAP) and s100β protein. Oxaliplatin treatment induced significant reduction of sensory and adrenergic innervations, as well as the total number and proportion of ChAT-IR neurons, and GFAP-IR glia, but increased s100β expression within the myenteric plexus of the distal colon. Treatment with oxaliplatin significantly alters nerve fibers and glial cells in the colonic myenteric plexus, which could contribute to long-term gastrointestinal side effects following chemotherapeutic treatment.

CSF inflammatory markers and neurocognitive function after addition of maraviroc to monotherapy darunavir/ritonavir in stable HIV patients: the CINAMMON study

CINAMMON is a phase IV, open-label, single-arm, pilot study assessing maraviroc (MVC) in the central nervous system (CNS) when added to darunavir/ritonavir monotherapy (DRV/r) in virologically suppressed HIV-infected subjects. CCR5 tropic participants on DRV/r were recruited. Participants remained on DRV/r for 12 week (w) (control phase). MVC 150 mg qd was added w12-w36 (intervention phase). Lumbar puncture (LP) and neurocognitive function (Cogstate) examinations scheduled at baseline, w12 and w36; MRI before w12, again at w36. Primary endpoint was CSF inflammatory marker changes during intervention phase. Secondary endpoints included changes in NC function and MRI parameters. CSF/plasma DRV/r concentrations measured at w12 and w36, MVC at w36. Nineteen patients recruited, 15 completed (17M, 2F). Dropouts: headache (2), knee problem (could not attend, 1), personal reasons (1). Mean age (range) 45.4 years (27.2-65.1), 13/19 white, 10/19 MSM. No changes in selected CSF markers were seen w12-w36. Overall NC function did not improve w12-w36: total age adjusted z score improved by 0.27 (weighted paired t test; p = 0.11); for executive function only, age adjusted z score improved by 0.54 (p = 0.03). MRI brain parameters unchanged. DRV plasma:CSF concentration ratio unchanged between w12 (132) and w36 (112; p = 0.577, Wilcoxon signed-rank). MVC plasma:CSF concentration ratio was 35 at w36. No changes in neuroinflammatory markers seen. In this small study, addition of 24w MVC 150 mg qd to stable DRV/r monotherapy showed possible improvement in executive function with no global NC effect. Learning effect cannot be excluded. This effect should be further evaluated.

Evaluation of dietary and lifestyle changes as modifiers of S100β levels in Alzheimer's disease

There is a significant body of research undertaken in order to elucidate the mechanisms underlying the pathology of Alzheimer's disease (AD), as well as to discover early detection biomarkers and potential therapeutic strategies. One such proposed biomarker is the calcium binding protein S100β, which, depending on its local concentration, is known to exhibit both neurotrophic and neuroinflammatory properties in the central nervous system. At present, relatively little is known regarding the effect of chronic S100β disruption in AD. Dietary intake has been identified as a modifiable risk factor for AD. Preliminary in vitro and animal studies have demonstrated an association between S100β expression and dietary intake which links to AD pathophysiology. This review describes the association of S100β to fatty acids, ketone bodies, insulin, and botanicals as well as the potential impact of physical activity as a lifestyle factor. We also discuss the prospective implications of these findings, including support of the use of a Mediterranean dietary pattern and/or the ketogenic diet as an approach to modify AD risk.

S100B: Correlation with Active Vitiligo Depigmentation

Vitiligo, the most common depigmenting disorder, is caused by immune destruction of melanocytes by cytotoxic CD8+ T cells. One weakness in vitiligo management is the lack of an assessment method for active depigmentation. Beginning with reports about increased S100B levels in different inflammatory and tissue damage processes, Speeckaert et al. explored correlations between the S100B dynamics and vitiligo activity, identifying high circulating S100B levels in patients with active depigmentation which were strongly correlated with the extent of affected skin surface. These authors have proposed S100B as a potential disease activity marker in vitiligo.

The potentials and limitations of neuro-biomarkers as predictors of outcome in neonates with birth asphyxia

Perinatal asphyxia and its complication, hypoxic-ischemic encephalopathy, are still among the major causes of perinatal mortality and morbidity. Despite accurate standard postnatal monitoring procedures, the post-insult period is crucial because at a time when radiologic pictures are still silent, brain damage may already be at a subclinical stage. Against this background, the measurement of quantitative parameters, such as constituents of nervous tissue, that are able to detect subclinical lesions at a stage when routine brain monitoring procedures are still silent, could be particularly useful. Therefore, in the present review we report the potentials and limitations of biomarkers in predicting outcome in neonates complicated by perinatal asphyxia.

A review of the clinical utility of serum S100B protein levels in the assessment of traumatic brain injury

Background

In order to improve injury assessment of brain injuries, protein markers of pathophysiological processes and tissue fate have been introduced in the clinic. The most studied protein “biomarker” of cerebral damage in traumatic brain injury (TBI) is the protein S100B. The aim of this narrative review is to thoroughly analyze the properties and capabilities of this biomarker with focus on clinical utility in the assessment of patients suffering from TBI.

Results

S100B has successfully been implemented in the clinic regionally (1) to screen mild TBI patients evaluating the need to perform a head computerized tomography, (2) to predict outcome in moderate-to-severe TBI patients, (3) to detect secondary injury development in brain-injured patients and (4) to evaluate treatment efficacy. The potential opportunities and pitfalls of S100B in the different areas usually refer to its specificity and sensitivity to detect and assess intracranial injury.

Conclusion

Given some shortcomings that should be realized, S100B can be used as a versatile screening, monitoring and prediction tool in the management of TBI patients.

A review of the clinical utility of serum S100B protein levels in the assessment of traumatic brain injury

BACKGROUND

In order to improve injury assessment of brain injuries, protein markers of pathophysiological processes and tissue fate have been introduced in the clinic. The most studied protein "biomarker" of cerebral damage in traumatic brain injury (TBI) is the protein S100B. The aim of this narrative review is to thoroughly analyze the properties and capabilities of this biomarker with focus on clinical utility in the assessment of patients suffering from TBI.

RESULTS

S100B has successfully been implemented in the clinic regionally (1) to screen mild TBI patients evaluating the need to perform a head computerized tomography, (2) to predict outcome in moderate-to-severe TBI patients, (3) to detect secondary injury development in brain-injured patients and (4) to evaluate treatment efficacy. The potential opportunities and pitfalls of S100B in the different areas usually refer to its specificity and sensitivity to detect and assess intracranial injury.

CONCLUSION

Given some shortcomings that should be realized, S100B can be used as a versatile screening, monitoring and prediction tool in the management of TBI patients.

Alpha band disruption in the AD-continuum starts in the Subjective Cognitive Decline stage: a MEG study

The consideration of Subjective Cognitive Decline (SCD) as a preclinical stage of AD remains still a matter of debate. Alpha band alterations represent one of the most significant changes in the electrophysiological profile of AD. In particular, AD patients exhibit reduced alpha relative power and frequency. We used alpha band activity measured with MEG to study whether SCD and MCI elders present these electrophysiological changes characteristic of AD, and to determine the evolution of the observed alterations across AD spectrum. The total sample consisted of 131 participants: 39 elders without SCD, 41 elders with SCD and 51 MCI patients. All of them underwent MEG and MRI scans and neuropsychological assessment. SCD and MCI patients exhibited a similar reduction in alpha band activity compared with the no SCD group. However, only MCI patients showed a slowing in their alpha peak frequency compared with both SCD and no SCD. These changes in alpha band were related to worse cognition. Our results suggest that AD-related alterations may start in the SCD stage, with a reduction in alpha relative power. It is later, in the MCI stage, where the slowing of the spectral profile takes place, giving rise to objective deficits in cognitive functioning.