The Human Gut Microbiota: A Dynamic Biologic Factory.

The human body constitutes a living environment for trillions of microorganisms, which establish the microbiome and, the largest population among them, reside within the gastrointestinal tract, establishing the gut microbiota. The term "gut microbiota" refers to a set of many microorganisms [mainly bacteria], which live symbiotically within the human host. The term "microbiome" means the collective genomic content of these microorganisms. The number of bacterial cells within the gut microbiota exceeds the host's cells; collectively and their genes quantitatively surpass the host's genes. Immense scientific research into the nature and function of the gut microbiota is unraveling its roles in certain human health activities such as metabolic, physiology, and immune activities and also in pathologic states and diseases. Interestingly, the microbiota, a dynamic ecosystem, inhabits a particular environment such as the human mouth or gut. Human microbiota can evolve and even adapt to the host's unique features such as eating habits, genetic makeup, underlying diseases, and even personalized habits. In the past decade, biologists and bioinformaticians have concentrated their research effort on the potential roles of the gut microbiome in the development of human diseases, particularly immune-mediated diseases and colorectal cancer, and have initiated the assessment of the impact of the gut microbiome on the host genome. In the present chapter, we focus on the biological features of gut microbiota, its physiology as a biological factory, and its impacts on the host's health and disease status.

Leptomeningeal Metastatic Prostate Cancer Imitating a Subdural Hematoma.

Metastases to the dura and adjacent parenchyma occur in 1%-2% of patients with prostate cancer. Dural metastases manifest as subdural fluid collections and present as a chronic subdural hematoma. We present a patient with advanced prostate cancer who experienced a fall and a traumatic brain injury. Computer tomography (CT) of the brain revealed a bilateral subdural hematoma (SDH). During the follow-up examination, the patient's mental status declined, and a follow-up brain CT showed an expansion of the SDH. Brain MRI with contrast demonstrated dural lesions suspicious for metastasis to the dura. Histopathologic examination of the lesions confirmed metastatic prostate adenocarcinoma. While uncommon, leptomeningeal-dural metastatic lesions stemming from prostate adenocarcinoma should be suspected in patients with known prostate cancer who present with subdural collections. This is even more significant if the patient with prostatic adenocarcinoma has sustained a recent head injury and presents with a subdural hematoma on neuroimaging. Brain MRI provides more data towards the differential diagnosis of these lesions and should be an essential part of the diagnostic workup. Biopsy and histopathologic examination of these lesions are indicated in the diagnostic workup of these uncommon lesions.

Human placental mesenchymal stem cells improve stroke outcomes via extracellular vesicles-mediated preservation of cerebral blood flow.

BACKGROUND: Besides long-term trans-differentiation into neural cells, benefits of stem cell therapy (SCT) in ischemic stroke may include secretion of protective factors, which partly reflects extracellular vesicle (EVs) released by stem cell. However, the mechanism(s) by which stem cells/EVs limit stroke injury have yet to be fully defined. METHODS: We evaluated the protection effect of human placenta mesenchymal stem cells (hPMSC) as a potential form of SCT in experimental ischemic stroke 'transient middle cerebral artery occusion (MCAO)/reperfusion' mice model. FINDINGS: We found for the first time that intraperitoneal administration of hPMSCs or intravenous hPMSC-derived EVs, given at the time of reperfusion, significantly protected the ipsilateral hemisphere from ischemic injury. This protection was associated with significant restoration of normal blood flow to the post-MCAO brain. More importantly, EVs derived from hPMSC promote paracrine-based protection of SCT in the MCAO model in a cholesterol/lipid-dependent manner. INTERPRETATION: Together, our results demonstrated beneficial effects of hPMSC/EVs in experimental stroke models which could permit the rapid "translation" of these cells into clinical trials in the near-term.

SC411 treatment can enhance survival in a mouse model of sickle cell disease.

Sickle cell disease (SCD) is one of the most common inherited blood disorder among African Americans affecting 70,000-100,000 individuals in the United States. It is characterized by abnormal hemoglobin (HbS) which develops into severe hemolytic anemia and vaso-occlusive crisis. Therefore, patients with SCD suffer from a chronic state of inflammation, which is responsible for multiple organ damage, ischemic attacks, and premature death. Another major hallmark of SCD patients is the abnormally low levels of omega-3 fatty acids, especially docosahexaenoic acid (DHA) in their red blood cell membranes. Treatment with DHA can reduce red blood cell adhesion and enhance cerebral blood flow, thus, our main goal is to investigate the effect of SC411, which is a novel, highly purified DHA ethyl ester formulation with a proprietary delivery platform in SCD. Utilizing a transgenic mouse model of SCD (HbSS-Townes) and recurrent hypoxic challenges (10%O2, 0.5% CO2 and balance N2 for 3 h) to mimic ischemic-like conditions, our data suggest that SC411 can elevate blood DHA and eicosapentaenoic acid (EPA) levels after 8 weeks of treatment. SC411 can also decrease arachidonic acid (AA) and sickling of red blood cells. In addition, SC411-treated SCD mice showed presented with cerebral blood flow, alleviated neuroinflammation, and revived working memory which ultimately enhanced overall survival. In summary, this study suggests that treatment with SC411 improves cellular and functional outcomes in SCD mice. This finding may provide novel therapeutic opportunities in the treatment against ischemic injury elicited by SCD.

Obstructive sleep apnea intensifies stroke severity following middle cerebral artery occlusion.

STUDY OBJECTIVES: Obstructive sleep apnea (OSA) is a sleep disorder caused by transient obstruction of the upper airway and results in intermittent hypoxia, sleep fragmentation, sympathetic nervous system activation, and arousal which can have an adverse effect on cardiovascular disease. It is theorized that OSA might intensify stroke injury. Our goal here was to develop a new model of experimental OSA and test its ability to aggravate behavioral and morphological outcomes following transient brain ischemia/reperfusion. METHODS: We used a 3D printed OSA device to expose C57BL6 mice to 3 h of OSA (obstructive apnea index of 20 events per hour) for three days. These mice were then subjected to ischemia/reperfusion using the middle cerebral artery occlusion model (MCAO) stroke and examined for overall survival, infarct size and neurological scoring. RESULTS: We found that OSA transiently decreased respiration and reduced oxygen saturation with bradycardia and tachycardia typical of human responses during apneic events. Brain injury from MCAO was significantly increased by OSA as measured by infarct size and location as well as by intensification of neurological deficits; mortality following MCAO was also increased in OSA animals. CONCLUSIONS: Our findings suggest that our new model of OSA alters respiratory and cardiovascular physiological functions and is associated with enhanced ischemia/reperfusion mediated injury in our non-invasive, OSA intensified model of stroke.

Nanoparticle-Encapsulated Bryostatin-1 Activates α-Secretase and PKC Isoforms In vitro and Facilitates Acquisition and Retention of Spatial Learning in an Alzheimer's Disease Mouse Model.

BACKGROUND: Alzheimer's disease (AD) animal models have revealed neuroprotective actions of Bryostatin-1 mediated by activation of novel PKC isoforms, suppression of beta-amyloid and downregulation of inflammatory and angiogenic events, making Bryostatin-1 an attractive candidate for attenuating AD-associated neural, vascular, and cognitive disturbances. OBJECTIVE: To further enhance Bryostatin-1 efficacy, nanoparticle-encapsulated Bryostatin-1 formulations were prepared. METHODS: We compared nano-encapsulated and unmodified Bryostatin-1 in in vitro models of neuronal PKC-d, PKC-e isoforms, α-secretase and studied nano-encapsulated Bryostatin-1 in an AD mouse model of spatial memory (BC3-Tg (APPswe, PSEN1 dE9) 85Dbo/J mice). RESULTS: We found that nanoencapsulated Bryostatin-1 formulations displayed activity greater or equal to that of unmodified Bryostatin-1 in PKC-δ and -ε and α-secretase activation assays. We next evaluated how treatment with a nanoencapsulated Bryostatin-1 formulation facilitated spatial learning in the Morris water maze. AD transgenic mice (6.5 to 8 months of age) were treated with nanoparticle encapsulated Bryostatin-1 formulation (1, 2.5, or 5 µg/mouse) three times the week before testing and then daily for each of the 5 days of testing. Across the acquisition phase, mice treated with nanoencapsulated Bryostatin-1 had shorter latencies, increased % time in the target zone and decreased % time in the opposite quadrant. The mice were given retention testing after a 2-week period without drug treatment. Mice treated with nanoencapsulated Bryostatin-1 had shorter latencies to find the escape platform, indicating retention of spatial memory. CONCLUSION: These data suggest that cognitive deficits associated with AD could be treated using highly potent nanoparticle-encapsulated formulations of Bryostatin-1.

Protein Arginine Methyltransferases in Cardiovascular and Neuronal Function.

The methylation of arginine residues by protein arginine methyltransferases (PRMTs) is a type of post-translational modification which is important for numerous cellular processes, including mRNA splicing, DNA repair, signal transduction, protein interaction, and transport. PRMTs have been extensively associated with various pathologies, including cancer, inflammation, and immunity response. However, the role of PRMTs has not been well described in vascular and neurological function. Aberrant expression of PRMTs can alter its metabolic products, asymmetric dimethylarginine (ADMA), and symmetric dimethylarginine (SDMA). Increased ADMA levels are recognized as an independent risk factor for cardiovascular disease and mortality. Recent studies have provided considerable advances in the development of small-molecule inhibitors of PRMTs to study their function under normal and pathological states. In this review, we aim to elucidate the particular roles of PRMTs in vascular and neuronal function as a potential target for cardiovascular and neurological diseases.

The Relationship Between Obstructive Sleep Apnea and Ruptured Intracranial Aneurysms.

STUDY OBJECTIVES: The role of obstructive sleep apnea (OSA) in the overall outcome of ruptured intracranial aneurysms (RIAs) is unknown. We have investigated the role of OSA in overall outcome of RIAs. METHODS: Data from 159 consecutive patients were retrospectively reviewed. A chi-square test and regression analysis were performed to determine the significant difference. A value of P < .05 was considered significant. RESULTS: The prevalence of OSA in RIAs was fivefold higher in the nonaneurysm patient group, P = .002. The number of patients with hypertension (P < .0001), body mass index ≥ 30 (P < .0001), hyperlipidemia (P = .018), chronic heart disease (P = .002) or prior ischemic stroke (P = .001) was significantly higher in the OSA group. Similarly, the number of wide-neck aneurysms (P < .0001) and aneurysm > 7 mm (P = .004), poor Hunt and Hess grade IV-V (P = .005), vasospasms, (P = .03), and patients with poor Modified Rankin Scale scores (3-6) was significantly higher in the OSA group (P < .0001). Interestingly, for the first time in univariate (P = .01) and multivariate (P = .003) regression analysis, OSA was identified as an individual predictor of unfavorable outcome of RIAs. In addition, hypertension (P = .04), smoking (P = .049), chronic heart disease (P = .01), and Hunt and Hess grade IV-V (P = .04) were revealed as predictors of poor outcome of RIAs. CONCLUSIONS: This is a novel study to determine the association between OSA and ruptured cerebral aneurysm in terms of comorbidities, size of aneurysm, severity of symptoms, and outcomes after treatment. In addition, for the first time, OSA is identified as a positive predictor of unfavorable outcome of RIAs.

Brain Endothelial Cells Release Apical and Basolateral Microparticles in Response to Inflammatory Cytokine Stimulation: Relevance to Neuroinflammatory Stress?

Microparticles (MP) are regarded both as biomarkers and mediators of many forms of pathology, including neurovascular inflammation. Here, we characterized vectorial release of apical and basolateral MPs (AMPs and BMPs) from control and TNF-α/IFN-γ treated human brain endothelial monolayers, studied molecular composition of AMPs and BMPs and characterized molecular pathways regulating AMP and BMP release. The effects of AMPs and BMPs on blood-brain barrier properties and human brain microvascular smooth muscle tonic contractility in vitro were also evaluated. We report that human brain microvascular endothelial cells release MPs both apically and basolaterally with both AMP and BMP release significantly increased following inflammatory cytokine challenge (3.5-fold and 3.9-fold vs. control, respectively). AMPs and BMPs both carry proteins derived from parent cells including those in BBB junctions (Claudin-1, -3, -5, occludin, VE-cadherin). AMPs and BMPs represent distinct populations whose release appears to be regulated by distinctly separate molecular pathways, which depend on signaling from Rho-associated, coiled-coil containing protein kinase (ROCK), calpain as well as cholesterol depletion. AMPs and BMPs modulate functions of neighboring cells including BBB endothelial solute permeability and brain vascular smooth muscle contractility. While control AMPs enhanced brain endothelial barrier, cytokine-induced AMPs impaired BBB. Cytokine-induced but not control BMPs significantly impaired human brain smooth muscle contractility as early as day 1. Taken together these results indicate that AMPs and BMPs may contribute to neurovascular inflammatory disease progression both within the circulation (AMP) and in the brain parenchyma (BMP).

Bioinformatics Analyses Determined the Distinct CNS and Peripheral Surrogate Biomarker Candidates Between Two Mouse Models for Progressive Multiple Sclerosis.

Previously, we have established two distinct progressive multiple sclerosis (MS) models by induction of experimental autoimmune encephalomyelitis (EAE) with myelin oligodendrocyte glycoprotein (MOG) in two mouse strains. A.SW mice develop ataxia with antibody deposition, but no T cell infiltration, in the central nervous system (CNS), while SJL/J mice develop paralysis with CNS T cell infiltration. In this study, we determined biomarkers contributing to the homogeneity and heterogeneity of two models. Using the CNS and spleen microarray transcriptome and cytokine data, we conducted computational analyses. We identified up-regulation of immune-related genes, including immunoglobulins, in the CNS of both models. Pro-inflammatory cytokines, interferon (IFN)-γ and interleukin (IL)-17, were associated with the disease progression in SJL/J mice, while the expression of both cytokines was detected only at the EAE onset in A.SW mice. Principal component analysis (PCA) of CNS transcriptome data demonstrated that down-regulation of prolactin may reflect disease progression. Pattern matching analysis of spleen transcriptome with CNS PCA identified 333 splenic surrogate markers, including Stfa2l1, which reflected the changes in the CNS. Among them, we found that two genes (PER1/MIR6883 and FKBP5) and one gene (SLC16A1/MCT1) were also significantly up-regulated and down-regulated, respectively, in human MS peripheral blood, using data mining.

Evaluation of the risk of cervical cancer in patients with Multiple Sclerosis treated with cytotoxic agents: A cohort study.

Background: Since most patients with relapsing-remitting multiple sclerosis (RRMS) are women, the present study aimed to determine whether treatment of patients with MS by cytotoxic agents is associated with an increased risk of cervical dysplasia. Cancer screening is often neglected in the chronic diseases such as MS, so more attention in this field was needed. Decreasing morbidity and mortality due to cervical cancer is the most important goal of screening in female MS patients especially in child bearing age. Thus, it can be said that this is the first study which investigated this important issue. Methods: A total of 129 individuals participated in this cohort study. They were assigned into 3 groups including 43 patients with MS who were treated with cytotoxic drugs, 43 patients with MS on immunomodulators, and 43 normal healthy controls. Pap smears were performed following standard methods and the results obtained from the three groups were compared by statistical analysis. Demographic data, Expanded Disability Status Scale (EDSS), and Pap smear changes were analyzed by SPSS software. Results: The most commonly detected abnormality in all examined patients and healthy controls was inflammation. Five patients with MS who were treated with cytotoxic agents revealed benign cellular changes (BCC) in their Pap smear that were statistically significant in comparison with other groups (P = 0.03). Patients who took Mitoxantrone presented BCC more than other groups [Odds ratio (OR) = 9.44, 95% confidence interval (CI): 1.46-60.70]. There was no significant difference between mean duration of MS diagnosis (P = 0.12), mean duration of previous MS treatments (P = 0.25), and mean duration of current MS treatments (P = 0.21) in patients with BCC compared to normal healthy controls or inflammatory change. Conclusion: According to the results of present study, BCC is more frequently observed in patients with MS who were treated with cytotoxic agents with immunosuppressive effect. Since BCC is a 'premalignant condition', the authors suggest that mandatory annual Pap smear should be performed for patients with MS who are treated with cytotoxic agents irrespective of their age in order to detect early signs of malignancy.

Multiple sclerosis pathogenesis: missing pieces of an old puzzle.

Traditionally, multiple sclerosis (MS) was considered to be a CD4 T cell-mediated CNS autoimmunity, compatible with experimental autoimmune encephalitis model, which can be characterized by focal lesions in the white matter. However, studies of recent decades revealed several missing pieces of MS puzzle and showed that MS pathogenesis is more complex than the traditional view and may include the following: a primary degenerative process (e.g. oligodendroglial pathology), generalized abnormality of normal-appearing brain tissue, pronounced gray matter pathology, involvement of innate immunity, and CD8 T cells and B cells. Here, we review these findings and discuss their implications in MS pathogenesis.

Cerebral ischemia and neuroregeneration.

Cerebral ischemia is one of the leading causes of morbidity and mortality worldwide. Although stroke (a form of cerebral ischemia)-related costs are expected to reach 240.67 billion dollars by 2030, options for treatment against cerebral ischemia/stroke are limited. All therapies except anti-thrombolytics (i.e., tissue plasminogen activator) and hypothermia have failed to reduce neuronal injury, neurological deficits, and mortality rates following cerebral ischemia, which suggests that development of novel therapies against stroke/cerebral ischemia are urgently needed. Here, we discuss the possible mechanism(s) underlying cerebral ischemia-induced brain injury, as well as current and future novel therapies (i.e., growth factors, nicotinamide adenine dinucleotide, melatonin, resveratrol, protein kinase C isozymes, pifithrin, hypothermia, fatty acids, sympathoplegic drugs, and stem cells) as it relates to cerebral ischemia.

Immunoregulation of Theiler's virus-induced demyelinating disease by glatiramer acetate without suppression of antiviral immune responses.

While most disease-modifying drugs (DMDs) regulate multiple sclerosis (MS) by suppressing inflammation, they can potentially suppress antiviral immunity, causing progressive multifocal leukoencephalopathy (PML). The DMD glatiramer acetate (GA) has been used for MS patients who are at high risk of PML. We investigated whether GA is safe for use in viral infections by using a model of MS induced by infection with Theiler's murine encephalomyelitis virus (TMEV). Treatment of TMEV-infected mice with GA neither enhanced viral loads nor suppressed antiviral immune responses, while it resulted in an increase in the Foxp3/Il17a ratio and IL-4/IL-10 production. This is the first study to suggest that GA could be safe for MS patients with a proven viral infection.

Utilizing the Modified T-Maze to Assess Functional Memory Outcomes After Cardiac Arrest.

BACKGROUND: Evaluating mild to moderate cognitive impairment in a global cerebral ischemia (i.e. cardiac arrest) model can be difficult due to poor locomotion after surgery. For example, rats who undergo surgical procedures and are subjected to the Morris water maze may not be able to swim, thus voiding the experiment. New Method: We established a modified behavioral spontaneous alternation T-maze test. The major advantage of the modified T-maze protocol is its relatively simple design that is powerful enough to assess functional learning/memory after ischemia. Additionally, the data analysis is simple and straightforward. We used the T-maze to determine the rats' learning/memory deficits both in the presence or absence of mild to moderate (6 min) asphyxial cardiac arrest (ACA). Rats have a natural tendency for exploration and will explore the alternate arms in the T-maze, whereas hippocampal-lesioned rats tend to adopt a side-preference resulting in decreased spontaneous alternation ratios, revealing the hippocampal-related functional learning/memory in the presence or absence of ACA. RESULTS: ACA groups have higher side-preference ratios and lower alternations as compared to control. Comparison with Existing Method(s): The Morris water and Barnes maze are more prominent for assessing learning/memory function. However, the Morris water maze is more stressful than other mazes. The Barnes maze is widely used to measure reference (long-term) memory, while ACA-induced neurocognitive deficits are more closely related to working (short-term) memory. CONCLUSIONS: We have developed a simple, yet effective strategy to delineate working (short-term) memory via the T-maze in our global cerebral ischemia model (ACA).

Coexistence of obstructive sleep apnea worsens the overall outcome of intracranial aneurysm: a pioneer study.

OBJECTIVE Obstructive sleep apnea (OSA) is associated with the progression of abdominal and thoracic aortic aneurysms. However, the role of OSA in the overall outcome of intracranial aneurysms (IAs) has not yet been established. Authors of this report investigated the role of OSA in the overall outcome of IAs. METHODS Radiological and clinical data on patients (from 2010 through 2015) with confirmed IA were retrospectively reviewed. Significant differences between the OSA and non-OSA groups were determined using a chi-square test. Logistic regression analysis was performed to identify the predictors of an unfavorable IA outcome. RESULTS Among the 283 patients with confirmed IAs, 45 patients (16%) were positively screened for OSA, a proportion that was significantly higher than the prevalence of OSA in nonaneurysmal neurosurgical patients (4%, p = 0.008). The percentage of patients with hypertension (p = 0.018), a body mass index ≥ 30 kg/m2 (p < 0.0001), hyperlipidemia (p = 0.034), diabetes mellitus (p = 0.005), chronic heart disease (CHD; p = 0.024), or prior stroke (p = 0.03) was significantly higher in the OSA group than in the non-OSA group. Similarly, the percentage of wide-necked aneurysms (p = 0.00001) and patients with a poor Hunt and Hess Grade IV-V (p = 0.01) was significantly higher in the OSA group than in the non-OSA group. In addition, the percentage of ruptured aneurysms (p = 0.03) and vasospasms (p = 0.03) was significantly higher in the OSA group. The percentage of patients with poor modified Rankin Scale (mRS) scores (3-6) was significantly higher in the OSA group (p = 0.03). A separate cohort of patients with ruptured IAs showed similar results. In both univariate (p = 0.01) and multivariate (p = 0.04) regression analyses, OSA was identified as an individual predictor of an unfavorable outcome. In addition, hypertension and prior stroke were revealed as predictors of a poor IA outcome. CONCLUSIONS Complications of IA such as rupture and vasospasm are often the consequence of uncontrolled OSA. Overall outcome (mRS) of IAs is also affected by the co-occurrence of OSA. Therefore, the coexistence of OSA with IA affects the outcome of IAs. Obstructive sleep apnea is a risk factor for a poor outcome in IA patients.