RESUMEN
Brain injury is highly associated with preterm birth. Complications of prematurity, including spontaneous or necrotizing enterocolitis (NEC)-associated intestinal perforations, are linked to lifelong neurologic impairment, yet the mechanisms are poorly understood. Early diagnosis of preterm brain injuries remains a significant challenge. Here, we identified subventricular zone echogenicity (SVE) on cranial ultrasound in preterm infants following intestinal perforations. The development of SVE was significantly associated with motor impairment at 2 years. SVE was replicated in a neonatal mouse model of intestinal perforation. Examination of the murine echogenic subventricular zone (SVZ) revealed NLRP3-inflammasome assembly in multiciliated FoxJ1+ ependymal cells and a loss of the ependymal border in this postnatal stem cell niche. These data suggest a mechanism of preterm brain injury localized to the SVZ that has not been adequately considered. Ultrasound detection of SVE may serve as an early biomarker for neurodevelopmental impairment after inflammatory disease in preterm infants.
Asunto(s)
Lesiones Encefálicas , Perforación Intestinal , Trastornos Motores , Nacimiento Prematuro , Lactante , Femenino , Recién Nacido , Humanos , Animales , Ratones , Recien Nacido Prematuro , Perforación Intestinal/complicaciones , Ventrículos Laterales , Nicho de Células Madre , Trastornos Motores/complicaciones , Lesiones Encefálicas/complicaciones , Lesiones Encefálicas/diagnóstico por imagenAsunto(s)
Encéfalo , Feto , Femenino , Cabeza , Humanos , Recién Nacido , Embarazo , Atención PrenatalRESUMEN
Brain function is highly dependent upon controlled energy metabolism whose loss heralds cognitive impairments. This is particularly notable in the aged individuals and in age-related neurodegenerative diseases. However, how metabolic homeostasis is disrupted in the aging brain is still poorly understood. Here we performed global, metabolomic and proteomic analyses across different anatomical regions of mouse brain at different stages of its adult lifespan. Interestingly, while severe proteomic imbalance was absent, global-untargeted metabolomics revealed an energymetabolic drift or significant imbalance in core metabolite levels in aged mouse brains. Metabolic imbalance was characterized by compromised cellular energy status (NAD decline, increased AMP/ATP, purine/pyrimidine accumulation) and significantly altered oxidative phosphorylation and nucleotide biosynthesis and degradation. The central energy metabolic drift suggests a failure of the cellular machinery to restore metabostasis (metabolite homeostasis) in the aged brain and therefore an inability to respond properly to external stimuli, likely driving the alterations in signaling activity and thus in neuronal function and communication.
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Envejecimiento/metabolismo , Encéfalo/metabolismo , Metabolismo Energético/fisiología , Animales , Metabolómica , Ratones , Fosforilación Oxidativa , ProteómicaRESUMEN
Humanized mice are frequently utilized in bench to bedside therapeutic tests to combat human infectious, cancerous and degenerative diseases. For the fields of hematology-oncology, regenerative medicine, and infectious diseases, the immune deficient mice have been used commonly in basic research efforts. Obstacles in true translational efforts abound, as the relationship between mouse and human cells in disease pathogenesis and therapeutic studies requires lengthy investigations. The interplay between human immunity and mouse biology proves ever more complicated when aging, irradiation, and human immune reconstitution are considered. All can affect a range of biochemical and behavioral functions. To such ends, we show age- and irradiation-dependent influences for the development of macrocytic hyper chromic anemia, myelodysplasia, blood protein reductions and body composition changes. Humanization contributes to hematologic abnormalities. Home cage behavior revealed day and dark cycle locomotion also influenced by human cell reconstitutions. Significant age-related day-to-day variability in movement, feeding and drinking behaviors were observed. We posit that this data serves to enable researchers to better design translational studies in this rapidly emerging field of mouse humanization.
RESUMEN
Heat maps are a commonly used visualization tool for metabolomic data where the relative abundance of ions detected in each sample is represented with color intensity. A limitation of applying heat maps to global metabolomic data, however, is the large number of ions that have to be displayed and the lack of information provided about important metabolomic parameters such as m/z and retention time. Here we address these challenges by introducing the interactive cluster heat map in the data-processing software XCMS Online. XCMS Online (xcmsonline.scripps.edu) is a cloud-based informatic platform designed to process, statistically evaluate, and visualize mass-spectrometry based metabolomic data. An interactive heat map is provided for all data processed by XCMS Online. The heat map is clickable, allowing users to zoom and explore specific metabolite metadata (EICs, Box-and-whisker plots, mass spectra) that are linked to the METLIN metabolite database. The utility of the XCMS interactive heat map is demonstrated on metabolomic data set generated from different anatomical regions of the mouse brain.
RESUMEN
Fluorocarbons are lipophobic and non-polar molecules that exhibit remarkable biocompatibility, with applications in liquid ventilation and synthetic blood. The unique properties of these compounds have also enabled mass spectrometry imaging of tissues where the fluorocarbons act as a Teflon-like coating for nanostructured surfaces to assist in desorption/ionization. Here we report fluorinated gold nanoparticles (f-AuNPs) designed to facilitate nanostructure imaging mass spectrometry. Irradiation of f-AuNPs results in the release of the fluorocarbon ligands providing a driving force for analyte desorption. The f-AuNPs allow for the mass spectrometry analysis of both lipophilic and polar (central carbon) metabolites. An important property of AuNPs is that they also act as contrast agents for X-ray microtomography and electron microscopy, a feature we have exploited by infusing f-AuNPs into tissue via fluorocarbon liquids to facilitate multimodal (molecular and anatomical) imaging.
Asunto(s)
Diagnóstico por Imagen/métodos , Oro/química , Nanopartículas del Metal/química , Espectrometría de Masas , Microscopía Electrónica , Nanoestructuras/químicaRESUMEN
BACKGROUND: Host-species specificity of the human immunodeficiency virus (HIV) limits pathobiologic, diagnostic and therapeutic research investigations to humans and non-human primates. The emergence of humanized mice as a model for viral infection of the nervous system has overcome such restrictions enabling research for HIV-associated end organ disease including behavioral, cognitive and neuropathologic deficits reflective of neuroAIDS. Chronic HIV-1 infection of NOD/scid-IL-2Rgcnull mice transplanted with human CD34+ hematopoietic stem cells (CD34-NSG) leads to persistent viremia, profound CD4+ T lymphocyte loss and infection of human monocyte-macrophages in the meninges and perivascular spaces. Murine cells are not infected with virus. METHODS: Changes in mouse behavior were measured, starting at 8 weeks after viral infection. These were recorded coordinate with magnetic resonance spectroscopy metabolites including N-acetylaspartate (NAA), creatine and choline. Diffusion tensor magnetic resonance imaging (DTI) was recorded against multispectral immunohistochemical staining for neuronal markers that included microtubule associated protein-2 (MAP2), neurofilament (NF) and synaptophysin (SYN); for astrocyte glial fibrillary acidic protein (GFAP); and for microglial ionized calcium binding adaptor molecule 1 (Iba-1). Oligodendrocyte numbers and integrity were measured for myelin associated glycoprotein (MAG) and myelin oligodendrocyte glycoprotein (MOG) antigens. RESULTS: Behavioral abnormalities were readily observed in HIV-1 infected mice. Longitudinal open field activity tests demonstrated lack of habituation indicating potential for memory loss and persistent anxiety in HIV-1 infected mice compared to uninfected controls. End-point NAA and creatine in the cerebral cortex increased with decreased MAG. NAA and glutamate decreased with decreased SYN and MAG. Robust inflammation reflected GFAP and Iba-1 staining intensities. DTI metrics were coordinate with deregulation of NF, Iba-1, MOG and MAG levels in the whisker barrel and MAP2, NF, MAG, MOG and SYN in the corpus callosum. CONCLUSIONS: The findings are consistent with some of the clinical, biochemical and pathobiologic features of human HIV-1 nervous system infections. This model will prove useful towards investigating the mechanisms of HIV-1 induced neuropathology and in developing novel biomarkers and therapeutic strategies for disease.
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Axones/patología , Encéfalo/virología , Trastornos del Conocimiento/fisiopatología , Infecciones por VIH , VIH-1 , Trastornos de la Memoria/fisiopatología , Animales , Encéfalo/patología , Trastornos del Conocimiento/virología , Humanos , Trastornos de la Memoria/virología , Ratones , Ratones Endogámicos NOD , Proteínas Asociadas a Microtúbulos/metabolismoRESUMEN
Historically, studies of brain metabolism have been based on targeted analyses of a limited number of metabolites. Here we present an untargeted mass spectrometry-based metabolomic strategy that has successfully uncovered differences in a broad array of metabolites across anatomical regions of the mouse brain. The NSG immunodeficient mouse model was chosen because of its ability to undergo humanization leading to numerous applications in oncology and infectious disease research. Metabolic phenotyping by hydrophilic interaction liquid chromatography and nanostructure imaging mass spectrometry revealed both water-soluble and lipid metabolite patterns across brain regions. Neurochemical differences in metabolic phenotypes were mainly defined by various phospholipids and several intriguing metabolites including carnosine, cholesterol sulfate, lipoamino acids, uric acid, and sialic acid, whose physiological roles in brain metabolism are poorly understood. This study helps define regional homeostasis for the normal mouse brain to give context to the reaction to pathological events.
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Encéfalo/metabolismo , Metabolómica , Animales , Encéfalo/anatomía & histología , Mapeo Encefálico , Cromatografía de Afinidad , Cromatografía Líquida de Alta Presión , Análisis por Conglomerados , Interacciones Hidrofóbicas e Hidrofílicas , Subunidad gamma Común de Receptores de Interleucina/deficiencia , Subunidad gamma Común de Receptores de Interleucina/genética , Subunidad gamma Común de Receptores de Interleucina/metabolismo , Ratones , Ratones Endogámicos NOD , Ratones Noqueados , Ratones SCID , Nanoestructuras/química , Resonancia Magnética Nuclear Biomolecular , Espectrometría de Masa por Ionización de ElectrosprayRESUMEN
Research directed at anatomical, integrative and functional activities of the central nervous system (CNS) can be realized through bioimaging. A wealth of data now demonstrates the utility of magnetic resonance imaging (MRI) towards unraveling complex neural connectivity operative in health and disease. A means to improve MRI sensitivity is through contrast agents and notably manganese (Mn²âº). The Mn²âº ions enter neurons through voltage-gated calcium channels and unlike other contrast agents such as gadolinium, iron oxide, iron platinum and imaging proteins, provide unique insights into brain physiology. Nonetheless, a critical question that remains is the brain target cells serving as sources for the signal of Mn²âº enhanced MRI (MEMRI). To this end, we investigated MEMRI's abilities to detect glial (astrocyte and microglia) and neuronal activation signals following treatment with known inflammatory inducing agents. The idea is to distinguish between gliosis (glial activation) and neuronal injury for the MEMRI signal and as such use the agent as a marker for neural activity in inflammatory and degenerative disease. We now demonstrate that glial inflammation facilitates Mn²âº neuronal ion uptake. Glial Mn²âº content was not linked to its activation. MEMRI performed on mice injected intracranially with lipopolysaccharide was associated with increased neuronal activity. These results support the notion that MEMRI reflects neuronal excitotoxicity and impairment that can occur through a range of insults including neuroinflammation. We conclude that the MEMRI signal enhancement is induced by inflammation stimulating neuronal Mn²âº uptake.
Asunto(s)
Imagen por Resonancia Magnética/métodos , Manganeso/fisiología , Neuroglía/metabolismo , Neuronas/metabolismo , Neuronas/patología , Animales , Animales Recién Nacidos , Técnicas de Cocultivo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos NOD , Ratones SCID , Neuronas/fisiología , Células PC12 , Ratas , Regulación hacia Arriba/fisiologíaRESUMEN
Metabolites are biomarkers for a broad range of central nervous system disorders serving as molecular drivers and byproducts of disease pathobiology. However, despite their importance, routine measures of brain tissue metabolomics are not readily available based on the requirements of rapid tissue preservation. They require preservation by microwave irradiation, rapid freezing or other methods designed to reduce post mortem metabolism. Our research on human immunodeficiency virus type one (HIV-1) infection has highlighted immediate needs to better link histology to neural metabolites. To this end, we investigated such needs in well-studied rodent models. First, the dynamics of brain metabolism during ex vivo tissue preparation was shown by proton magnetic resonance spectroscopy in normal mice. Second, tissue preservation methodologies were assessed using liquid chromatography tandem mass spectrometry and immunohistology to measure metabolites and neural antigens. Third, these methods were applied to two animal models. In the first, immunodeficient mice reconstituted with human peripheral blood lymphocytes then acutely infected with HIV-1. In the second, NOD scid IL2 receptor gamma chain knockout mice were humanized with CD34+ human hematopoietic stem cells and chronically infected with HIV-1. Replicate infected animals were treated with nanoformulated antiretroviral therapy (nanoART). Results from chronic infection showed that microgliosis was associated with increased myoinostitol, choline, phosphocholine concentrations and with decreased creatine concentrations. These changes were partially reversed with nanoART. Metabolite responses were contingent on the animal model. Taken together, these studies integrate brain metabolomics with histopathology towards uncovering putative biomarkers for neuroAIDS.
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Complejo SIDA Demencia/metabolismo , Complejo SIDA Demencia/patología , Encéfalo/metabolismo , Encéfalo/patología , Modelos Animales de Enfermedad , Animales , Cromatografía Liquida , Criopreservación/métodos , Infecciones por VIH/metabolismo , Infecciones por VIH/patología , Humanos , Espectroscopía de Resonancia Magnética , Metabolómica , Ratones , Ratones Endogámicos NOD , Ratones Noqueados , Ratones SCID , Microondas , Espectrometría de Masas en Tándem , Fijación del Tejido/métodosRESUMEN
Amino acids and myo-inositol have long been proposed as putative biomarkers for neurodegenerative diseases. Accurate measures and stability have precluded their selective use. To this end, a sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method based on multiple reaction monitoring was developed to simultaneously quantify glutamine, glutamate, γ-aminobutyric acid (GABA), aspartic acid, N-acetyl aspartic acid, taurine, choline, creatine, phosphocholine and myo-inositol in mouse brain by methanol extractions. Chromatography was performed using a hydrophilic interaction chromatography silica column within in a total run time of 15 min. The validated method is selective, sensitive, accurate, and precise. The method has a limit of quantification ranging from 2.5 to 20 ng/ml for a range of analytes and a dynamic range from 2.5-20 to 500-4000 ng/ml. This LC-MS/MS method was validated for biomarker discovery in models of human neurological disorders.
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Aminoácidos/análisis , Química Encefálica , Cromatografía Líquida de Alta Presión/métodos , Inositol/análisis , Espectrometría de Masas en Tándem/métodos , Animales , Interacciones Hidrofóbicas e Hidrofílicas , Ratones , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
Neuronal damage induced by ongoing human immunodeficiency virus type 1 (HIV-1) infection was investigated in humanized NOD/scid-IL-2Rγ(c)(null) mice transplanted at birth with human CD34-positive hematopoietic stem cells. Mice infected at 5 months of age and followed for up to 15 weeks maintained significant plasma viral loads and showed reduced numbers of CD4(+) T-cells. Prospective serial proton magnetic resonance spectroscopy tests showed selective reductions in cortical N-acetyl aspartate in infected animals. Diffusion tensor imaging revealed structural changes in cortical gray matter. Postmortem immunofluorescence brain tissue examinations for neuronal and glial markers, captured by multispectral imaging microscopy and quantified by morphometric and fluorescence emission, showed regional reduction of neuronal soma and synaptic architectures. This was evidenced by loss of microtubule-associated protein 2, synaptophysin, and neurofilament antigens. This study is the first, to our knowledge, demonstrating lost neuronal integrity after HIV-1 infection in humanized mice. As such, the model permits studies of the relationships between ongoing viral replication and virus-associated neurodegeneration.
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Progresión de la Enfermedad , Infecciones por VIH/patología , VIH-1/inmunología , Red Nerviosa/patología , Neuronas/patología , Animales , Antígenos CD34/administración & dosificación , Antígenos CD34/biosíntesis , Trastornos del Conocimiento/inmunología , Trastornos del Conocimiento/patología , Infecciones por VIH/inmunología , Trasplante de Células Madre Hematopoyéticas/métodos , Humanos , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos NOD , Ratones Noqueados , Ratones SCID , Red Nerviosa/inmunología , Neuroglía/inmunología , Neuroglía/patología , Neuroglía/virología , Neuronas/inmunología , Neuronas/virología , Estudios Prospectivos , Carga Viral/métodos , Replicación Viral/inmunologíaRESUMEN
BACKGROUND: Many recent studies have identified white matter abnormalities in late life depression (LLD). These abnormalities include an increased volume of discrete white matter hyperintensities on T2-weighted imaging (WMH) and changes in the diffusion tensor properties of water. However, no study of LLD to date has examined the integrity of white matter outside of WMH (i.e., in normal-appearing white matter). METHODS: We performed T1- and T2-weighted imaging as well as diffusion tensor imaging (DTI) in depressed elderly subjects (n = 73) and nondepressed control subjects (n = 23) matched for age and cerebrovascular risk factors. The structural images were segmented into white matter, gray matter, cerebrospinal fluid, and WMH. The DTI parameters were calculated in white matter regions of interest after excluding the WMH. RESULTS: Compared with control subjects, in the LLD group there were widespread abnormalities in DTI parameters, particularly in prefrontal regions. From a comprehensive neuropsychological battery, the strongest correlations were observed between cognitive processing speed and DTI abnormalities. CONCLUSIONS: These results suggest that further investigation is warranted to determine potential reversibility and/or prognosis in LLD.
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Mapeo Encefálico , Encéfalo/patología , Depresión/patología , Imagen de Difusión por Resonancia Magnética , Anciano , Encéfalo/metabolismo , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Masculino , Persona de Mediana EdadRESUMEN
Animal models with complex cortical development are useful for improving our understanding of the wide spectrum of neurodevelopmental challenges facing human preterm infants. MRI techniques can define both cerebral injury and alterations in cerebral development with translation between animal models and the human infant. We hypothesized that the immature ferret would display a similar sequence of brain development [both gray (GM) and white matter (WM)] to that of the preterm human infant. We describe postnatal ferret neurodevelopment with conventional and diffusion MRI. The ferret is born lissencephalic with a thin cortical plate and relatively large ventricles. Cortical folding and WM maturation take place during the first month of life. From the mid-second through the third week of postnatal life, the ferret brain undergoes a similar, though less complex, pattern of maturational changes to those observed in the human brain during the second half of gestation. GM anisotropy decreases rapidly in the first 3 wks of life, followed by an upward surge of surface folding and WM anisotropy over the next 2 wks.
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Encéfalo/crecimiento & desarrollo , Hurones/crecimiento & desarrollo , Animales , Anisotropía , Imagen por Resonancia Magnética/métodosRESUMEN
OBJECTIVE: Segmented brain white matter hyperintensities were compared between subjects with late-life depression and age-matched subjects with similar vascular risk factor scores. Correlations between neuropsychological performance and whole brain-segmented white matter hyperintensities and white and gray matter volumes were also examined. METHOD: Eighty-three subjects with late-life depression and 32 comparison subjects underwent physical examination, psychiatric evaluation, neuropsychological testing, vascular risk factor assessment, and brain magnetic resonance imaging (MRI). Automated segmentation methods were used to compare the total brain and regional white matter hyperintensity burden between depressed patients and comparison subjects. RESULTS: Depressed patients and comparison subjects did not differ in demographic variables, including vascular risk factor, or whole brain-segmented volumes. However, depressed subjects had seven regions of greater white matter hyperintensities located in the following white matter tracts: the superior longitudinal fasciculus, fronto-occipital fasciculus, uncinate fasciculus, extreme capsule, and inferior longitudinal fasciculus. These white matter tracts underlie brain regions associated with cognitive and emotional function. In depressed patients but not comparison subjects, volumes of three of these regions correlated with executive function; whole brain white matter hyperintensities correlated with executive function; whole brain white matter correlated with episodic memory, processing speed, and executive function; and whole brain gray matter correlated with processing speed. CONCLUSIONS: These findings support the hypothesis that the strategic location of white matter hyperintensities may be critical in late-life depression. Further, the correlation of neuropsychological deficits with the volumes of whole brain white matter hyperintensities and gray and white matter in depressed subjects but not comparison subjects supports the hypothesis of an interaction between these structural brain components and depressed status.
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Encéfalo/patología , Trastornos Cerebrovasculares/diagnóstico , Trastornos Cerebrovasculares/epidemiología , Trastorno Depresivo Mayor/diagnóstico , Trastorno Depresivo Mayor/epidemiología , Imagen por Resonancia Magnética/métodos , Anciano , Algoritmos , Mapeo Encefálico , Trastornos Cerebrovasculares/patología , Trastornos del Conocimiento/diagnóstico , Trastornos del Conocimiento/epidemiología , Trastornos del Conocimiento/patología , Comorbilidad , Trastorno Depresivo Mayor/patología , Diagnóstico Diferencial , Femenino , Humanos , Imagen por Resonancia Magnética/estadística & datos numéricos , Masculino , Vías Nerviosas , Pruebas Neuropsicológicas/estadística & datos numéricos , Factores de RiesgoRESUMEN
Spatial neglect is a syndrome following stroke manifesting attentional deficits in perceiving and responding to stimuli in the contralesional field. We examined brain network integrity in patients with neglect by measuring coherent fluctuations of fMRI signals (functional connectivity). Connectivity in two largely separate attention networks located in dorsal and ventral frontoparietal areas was assessed at both acute and chronic stages of recovery. Connectivity in the ventral network, part of which directly lesioned, was diffusely disrupted and showed no recovery. In the structurally intact dorsal network, interhemispheric connectivity in posterior parietal cortex was acutely disrupted but fully recovered. This acute disruption, and disrupted connectivity in specific pathways in the ventral network, strongly correlated with impaired attentional processing across subjects. Lastly, disconnection of the white matter tracts connecting frontal and parietal cortices was associated with more severe neglect and more disrupted functional connectivity. These findings support a network view in understanding neglect.
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Lóbulo Frontal/fisiopatología , Vías Nerviosas/fisiopatología , Lóbulo Parietal/fisiopatología , Trastornos de la Percepción/patología , Percepción Espacial/fisiología , Mapeo Encefálico , Imagen de Difusión por Resonancia Magnética/métodos , Femenino , Lóbulo Frontal/irrigación sanguínea , Lateralidad Funcional , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética/métodos , Persona de Mediana Edad , Vías Nerviosas/irrigación sanguínea , Oxígeno/sangre , Lóbulo Parietal/irrigación sanguínea , Trastornos de la Percepción/fisiopatología , Estimulación Luminosa/métodos , Desempeño PsicomotorRESUMEN
OBJECT: The authors conducted a prospective study to evaluate the clinical and radiological outcomes and complications associated with uni- and bilateral transforaminal lumbar interbody fusion (TLIF) performed using carbon fiber Brantigan I/F Cages and pedicle screw fixation. METHODS: Forty-two consecutive patients who had undergone uni- or bilateral TLIF between February 1999 and July 2000 were prospectively evaluated. Clinical outcome was graded using a modified Prolo Scale, the McGill Pain Index Scale, a follow-up questionnaire, and charts. An independent radiologist assessed radiological outcomes. All patients were followed for at least 1 year. Based on Prolo Scale scores, an excellent or good 1-year outcome was achieved in 73% of patients; 90% of patients responded that they would undergo the procedure again. At 1 year, radiographic fusion was demonstrated in 74% and was statistically related to clinical outcome (p < 0.05). There were no deaths or major hardware failures. Complications requiring repeated surgery included one case of cerebrospinal fluid (CSF) leakage and one case in which the hemovac drain was retained. There were four cases involving minor wound infections, eight involving CSF leaks, and none requiring repeated surgery. On routine follow-up radiography one pedicle screw was found to be broken; the patient remained asymptomatic and fusion occurred. CONCLUSIONS: Unilateral and bilateral TLIF involving placement of carbon fiber cages and pedicle screw fixation are effective treatment options in patients with indications for lumbar arthrodesis. The procedures result in acceptable rates of fusion and clinical success, and a minimal incidence of morbidity when performed by an experienced surgeon.