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Aging dogs serve as a valuable preclinical model for Alzheimer's disease (AD) due to their natural age-related development of ß-amyloid (Aß) plaques, human-like metabolism, and large brains that are ideal for studying structural brain aging trajectories from serial neuroimaging. Here we examined the effects of chronic treatment with the calcineurin inhibitor (CNI) tacrolimus or the nuclear factor of activated T cells (NFAT)-inhibiting compound Q134R on age-related canine brain atrophy from a longitudinal study in middle-aged beagles (36 females, 7 males) undergoing behavioral enrichment. Annual MRI was analyzed using modern, automated techniques for region-of-interest-based and voxel-based volumetric assessments. We found that the frontal lobe showed accelerated atrophy with age, while the caudate nucleus remained relatively stable. Remarkably, the hippocampus increased in volume in all dogs. None of these changes were influenced by tacrolimus or Q134R treatment. Our results suggest that behavioral enrichment can prevent atrophy and increase the volume of the hippocampus but does not prevent aging-associated prefrontal cortex atrophy.
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Envejecimiento , Atrofia , Encéfalo , Tacrolimus , Animales , Perros , Femenino , Atrofia/patología , Masculino , Envejecimiento/patología , Encéfalo/patología , Encéfalo/efectos de los fármacos , Tacrolimus/farmacología , Conducta Animal/efectos de los fármacos , Imagen por Resonancia MagnéticaRESUMEN
Treatment with mineralocorticoid receptor (MR) antagonists beginning at the outset of disease, or early thereafter, prevents pulmonary vascular remodeling in preclinical models of pulmonary arterial hypertension (PAH). However, the efficacy of MR blockade in established disease, a more clinically relevant condition, remains unknown. Therefore, we investigated the effectiveness of two MR antagonists, eplerenone (EPL) and spironolactone (SPL), after the development of severe right ventricular (RV) dysfunction in the rat SU5416-hypoxia (SuHx) PAH model. Cardiac magnetic resonance imaging (MRI) in SuHx rats at the end of week 5, before study treatment, confirmed features of established disease including reduced RV ejection fraction and RV hypertrophy, pronounced septal flattening with impaired left ventricular filling and reduced cardiac index. Five weeks of treatment with either EPL or SPL improved left ventricular filling and prevented the further decline in cardiac index compared with placebo. Interventricular septal displacement was reduced by EPL whereas SPL effects were similar, but not significant. Although MR antagonists did not significantly reduce pulmonary artery pressure or vessel remodeling in SuHx rats with established disease, animals with higher drug levels had lower pulmonary pressures. Consistent with effects on cardiac function, EPL treatment tended to suppress MR and proinflammatory gene induction in the RV. In conclusion, MR antagonist treatment led to modest, but consistent beneficial effects on interventricular dependence after the onset of significant RV dysfunction in the SuHx PAH model. These results suggest that measures of RV structure and/or function may be useful endpoints in clinical trials of MR antagonists in patients with PAH.
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Hipertensión Pulmonar , Hipertensión Arterial Pulmonar , Disfunción Ventricular Derecha , Animales , Modelos Animales de Enfermedad , Hipertensión Pulmonar Primaria Familiar , Humanos , Hipertensión Pulmonar/tratamiento farmacológico , Hipoxia/tratamiento farmacológico , Indoles , Antagonistas de Receptores de Mineralocorticoides/farmacología , Antagonistas de Receptores de Mineralocorticoides/uso terapéutico , Pirroles , Ratas , Disfunción Ventricular Derecha/tratamiento farmacológicoRESUMEN
BACKGROUND: Metabolomics may represent an avenue for diagnosis of equine ascending placentitis. OBJECTIVES: To characterise the plasma metabolomic profile in healthy mares and mares with induced ascending placentitis, with the goal of identifying metabolites with potential clinical value for early diagnosis of placentitis. STUDY DESIGN: Controlled in vivo experiment. METHODS: Placentitis was induced in 10 late-term pregnant pony mares via Streptococcal equi subsp. zooepidemicus inoculation in five mares between days 285 and 290 of gestation, while five mares served as healthy controls. Repeated ultrasound examinations and jugular venipuncture were performed to obtain combined thickness of the uterus and placenta (CTUP) and plasma for NMR spectroscopy. Mares with increased CTUP were diagnosed with placentitis and treated in accordance with published therapeutic recommendations. NMR metabolomic analysis was performed to identify and quantify plasma metabolites at each time point. Concentrations were compared using ANOVA with repeated-measures and PLS-DA analysis. RESULTS: Four hours post-inoculation, a significant increase was detected in the metabolites alanine, phenylalanine, histidine, pyruvate, citrate, glucose, creatine, glycolate, lactate and 3-hydroxyisobutyrate that returned to baseline by 12 hours. On day 4, a significant reduction in the metabolites alanine, phenylalanine, histidine, tyrosine, pyruvate, citrate, glycolate, lactate and dimethylsulfone was seen in infected mares compared with controls. MAIN LIMITATIONS: There were small numbers of mares within groups. In addition, this work compares healthy animals with animals treated with multimodal therapeutics following diagnosis of placentitis without an untreated cohort. CONCLUSIONS: Two phases of metabolite changes were noted after experimental infection: An immediate rise in metabolite concentration involved in energy, nitrogen, hydrogen and oxygen metabolism within 4 hours after inoculation that was followed by a decrease in metabolite concentrations involved in energy and nitrogen metabolism at 4 days, coinciding with ultrasonographic diagnosis of placentitis.
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Enfermedades de los Caballos , Enfermedades Placentarias , Streptococcus equi , Animales , Femenino , Caballos , Metabolómica , Enfermedades Placentarias/veterinaria , Plasma , EmbarazoRESUMEN
BACKGROUND: The spinal cord is composed of nine distinct cellular laminae that currently can only be visualized by histological methods. Developing imaging methods that can visualize laminar architecture in-vivo is of significant interest. Manganese enhanced magnetic resonance imaging (MEMRI) yields valuable architectural and functional information about the brain and has great potential in characterizing neural pathways in the spinal cord. Here we apply MEMRI to visualize laminae architecture in the thoracic region of the spinal cord with ultra-high resolution. NEW METHOD: Manganese chloride (MnCl2) was delivered systemically and imaging of the lumbar and thoracic spinal cord levels was acquired in high field, 11.7â¯T MRI scanner, 48â¯h following MnCl2 administration. RESULTS: Here we demonstrate laminar specific signal enhancement in the spinal cord of rats administered with MnCl2 with 69⯵mâ¯in-plane resolution. We also report reduced T1 values over time in MnCl2 groups across laminae IIX. COMPARISONS WITH EXISTING METHODS: This is the first study to demonstrate that MEMRI is capable of identifying spinal laminae at a high resolution of 69⯵mâ¯in a living animal. This would enable the visualization of architecture and function of distinct regions with improved resolution, in healthy and diseased animal models. CONCLUSIONS: The regions with the largest T1 enhancements were observed to correspond to laminae that contain either high cell density or large motor neurons, making MEMRI an excellent tool for studying spinal cord architecture, physiology and function in different animal models.
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Aumento de la Imagen , Imagen por Resonancia Magnética , Animales , Encéfalo , Manganeso , Ratas , Médula Espinal/diagnóstico por imagenRESUMEN
We used nuclear magnetic spectroscopy (NMR) to evaluate the metabolic impacts of crude oil, Corexit 5900A, a dispersant, and a crude oil Corexit 5900A mixture exposure on skeletal muscle, heart, and liver physiology of hatchling loggerhead sea turtles (Caretta caretta). Tissue samples were obtained from 22 seven-day-old hatchlings after a four day cutaneous exposure to environmentally relevant concentrations of crude oil, Corexit 5900A, a combination of crude oil and Corexit 9500A, or a seawater control. We identified 38 metabolites in the aqueous extracts of the liver, and 30 metabolites in both the skeletal and heart muscle aqueous extracts, including organic acids/osmolytes, energy compounds, amino acids, ketone bodies, nucleosides, and nucleotides. Skeletal muscle lactate, creatines, and taurine concentrations were significantly lower in hatchlings exposed to crude oil than in control hatchlings. Lactate, taurine, and cholines appeared to be the basis of some variation in hatchling heart samples, and liver inosine, uracil, and uridine appeared to be influenced by Corexit and crude oil exposure. Observed decreases in concentrations of lactate and creatines may reflect energy depletion in skeletal muscle of oil-exposed animals, while decreased taurine concentrations in these animals may reflect higher oxidative stress.
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Increased mTORC1 signaling from TSC1/TSC2 inactivation is found in cancer and causes tuberous sclerosis complex (TSC). The role of mesenchymal-derived cells in TSC tumorigenesis was investigated through disruption of Tsc2 in craniofacial and limb bud mesenchymal progenitors. Tsc2cKOPrrx1-cre mice had shortened lifespans and extensive hamartomas containing abnormal tortuous, dilated vessels prominent in the forelimbs. Abnormalities were blocked by the mTORC1 inhibitor sirolimus. A Tsc2/mTORC1 expression signature identified in Tsc2-deficient fibroblasts was also increased in bladder cancers with TSC1/TSC2 mutations in the TCGA database. Signature component Lgals3 encoding galectin-3 was increased in Tsc2-deficient cells and serum of Tsc2cKOPrrx1-cre mice. Galectin-3 was increased in TSC-related skin tumors, angiomyolipomas, and lymphangioleiomyomatosis with serum levels in patients with lymphangioleiomyomatosis correlating with impaired lung function and angiomyolipoma presence. Our results demonstrate Tsc2-deficient mesenchymal progenitors cause aberrant morphogenic signals, and identify an expression signature including Lgals3 relevant for human disease of TSC1/TSC2 inactivation and mTORC1 hyperactivity.
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Galectina 3/metabolismo , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Células Madre Mesenquimatosas/fisiología , Neoplasias Cutáneas/fisiopatología , Proteínas Supresoras de Tumor/metabolismo , Animales , Proteínas Sanguíneas , Galectinas , Humanos , Ratones , Ratones Noqueados , Proteína 2 del Complejo de la Esclerosis Tuberosa , Proteínas Supresoras de Tumor/deficienciaRESUMEN
The regulatory control of cardiac endoplasmic reticulum (ER) stress is incompletely characterized. As ER stress signaling upregulates the E3-ubiquitin ligase Parkin, we investigated the role of Parkin in cardiac ER stress. Parkin knockout mice exposed to aortic constriction-induced cardiac pressure-overload or in response to systemic tunicamycin (TM) developed adverse ventricular remodeling with excessive levels of the ER regulatory C/EBP homologous protein CHOP. CHOP was identified as a Parkin substrate and its turnover was Parkin-dose and proteasome-dependent. Parkin depletion in cardiac HL-1 cells increased CHOP levels and enhanced susceptibility to TM-induced cell death. Parkin reconstitution rescued this phenotype and the contribution of excess CHOP to this ER stress injury was confirmed by reduction in TM-induced cell death when CHOP was depleted in Parkin knockdown cardiomyocytes. Isogenic Parkin mutant iPSC-derived cardiomyocytes showed exaggerated ER stress induced CHOP and apoptotic signatures and myocardium from subjects with dilated cardiomyopathy showed excessive Parkin and CHOP induction. This study identifies that Parkin functions to blunt excessive CHOP to prevent maladaptive ER stress-induced cell death and adverse cardiac ventricular remodeling. Additionally, Parkin is identified as a novel post-translational regulatory moderator of CHOP stability and uncovers an additional stress-modifying function of this E3-ubiquitin ligase.
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Cardiomiopatía Dilatada/metabolismo , Estrés del Retículo Endoplásmico , Miocitos Cardíacos/metabolismo , Factor de Transcripción CHOP/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Animales , Apoptosis , Cardiomiopatía Dilatada/patología , Línea Celular , Línea Celular Tumoral , Células HEK293 , Humanos , Células Madre Pluripotentes Inducidas/citología , Células Madre Pluripotentes Inducidas/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Miocitos Cardíacos/citología , Ubiquitina-Proteína Ligasas/genética , Remodelación VentricularRESUMEN
We used proton nuclear magnetic resonance spectroscopy (1H-NMR) to evaluate metabolic impacts of environmentally relevant crude oil and Corexit exposures on the physiology of hatchling loggerhead sea turtles (Caretta caretta). Sample extraction and data acquisition methods for very small volume whole blood samples and sources of variation between individual hatchlings were assessed. Sixteen unclotted, whole blood samples were obtained from 7-day-old hatchlings after a 4-day cutaneous exposure to either control seawater, crude oil, Corexit 9500A or a combination of crude oil and Corexit 9500A. After extraction, one- and two-dimensional 1H-NMR spectra of the samples were obtained, and 17 metabolites were identified and confirmed in the whole blood spectra. Variation among samples due to the concentrations of metabolites 3-hydroxybutyrate, lactate, trimethylamine oxide and propylene glycol did not statistically correlate with treatment group. However, the characterization of the hatchling loggerhead whole blood metabolome provides a foundation for future metabolomic research with sea turtles and a basis for the study of tissues from exposed hatchling sea turtles.
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INTRODUCTION: Nanoparticles may serve as a promising means to deliver novel therapeutics to the myocardium following myocardial infarction. We sought to determine whether lipid-based liposomal nanoparticles can be shown through different imaging modalities to specifically target injured myocardium following intravenous injection in an ischemia-reperfusion murine myocardial infarction model. METHODS: Mice underwent ischemia-reperfusion surgery and then either received tail-vein injection with gadolinium- and fluorescent-labeled liposomes or no injection (control). The hearts were harvested 24h later and underwent T1 and T2-weighted ex vivo imaging using a 7 Tesla Bruker magnet. The hearts were then sectioned for immunohistochemistry and optical fluorescent imaging. RESULTS: The mean size of the liposomes was 100nm. T1-weighted signal intensity was significantly increased in the ischemic vs. the non-ischemic myocardium for mice that received liposomes compared with control. Optical imaging demonstrated significant fluorescence within the infarct area for the liposome group compared with control (163±31% vs. 13±14%, p=0.001) and fluorescent microscopy confirmed the presence of liposomes within the ischemic myocardium. CONCLUSIONS: Liposomes traffic to the heart and preferentially home to regions of myocardial injury, enabling improved diagnosis of myocardial injury and could serve as a vehicle for drug delivery.
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Albúminas/farmacocinética , Medios de Contraste/farmacocinética , Colorantes Fluorescentes/farmacocinética , Gadolinio DTPA/farmacocinética , Imagen por Resonancia Magnética , Infarto del Miocardio/diagnóstico por imagen , Daño por Reperfusión Miocárdica/diagnóstico por imagen , Miocardio/metabolismo , Imagen Óptica/métodos , Fosfatidiletanolaminas/farmacocinética , Albúminas/administración & dosificación , Animales , Medios de Contraste/administración & dosificación , Modelos Animales de Enfermedad , Colorantes Fluorescentes/administración & dosificación , Gadolinio DTPA/administración & dosificación , Inmunohistoquímica , Inyecciones Intravenosas , Liposomas , Masculino , Ratones , Microscopía Fluorescente , Infarto del Miocardio/metabolismo , Daño por Reperfusión Miocárdica/metabolismo , Nanopartículas , Tamaño de la Partícula , Fosfatidiletanolaminas/administración & dosificación , Distribución TisularRESUMEN
Late gadolinium enhanced (LGE) cardiac magnetic resonance (CMR) imaging can detect the presence of myocardial infarction from ischemic cardiomyopathies (ICM). However, it is more challenging to detect diffuse myocardial fibrosis from non-ischemic cardiomyopathy (NICM) with this technique due to more subtle and heterogeneous enhancement of the myocardium. This study investigates whether high-resolution LGE CMR can detect age-related myocardial fibrosis using quantitative texture analysis with histological validation. LGE CMR of twenty-four rat hearts (twelve 6-week-old and twelve 2-year-old) was performed using a 7T MRI scanner. Picrosirius red was used as the histopathology reference for collagen staining. Fibrosis in the myocardium was quantified with standard deviation (SD) threshold methods from the LGE CMR images and 3D contrast texture maps that were computed from gray level co-occurrence matrix of the CMR images. There was a significant increase of collagen fibers in the aged compared to the young rat histology slices (2.60±0.27 %LV vs. 1.24±0.29 %LV, p<0.01). Both LGE CMR and texture images showed a significant increase of myocardial fibrosis in the elderly compared to the young rats. Fibrosis in the LGE CMR images correlated strongly with histology with the 3 SD threshold (r=0.84, y=0.99x+0.00). Similarly, fibrosis in the contrast texture maps correlated with the histology using the 4 SD threshold (r=0.89, y=1.01x+0.00). High resolution ex-vivo LGE CMR can detect the presence of diffuse fibrosis that naturally developed in elderly rat hearts. Our results suggest that texture analysis may improve the assessment of myocardial fibrosis in LGE CMR images.
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Envejecimiento/patología , Gadolinio/farmacología , Procesamiento de Imagen Asistido por Computador/métodos , Imagen por Resonancia Magnética , Infarto del Miocardio/diagnóstico por imagen , Miocardio/patología , Animales , Medios de Contraste/farmacología , Fibrosis , Humanos , Masculino , Radiografía , Ratas , Ratas Endogámicas F344RESUMEN
AIMS: Atypical chemokine receptor 1 (Ackr1; previously known as the Duffy antigen receptor for chemokines or Darc) is thought to regulate acute inflammatory responses in part by scavenging inflammatory CC and CXC chemokines; however, evidence for a role in chronic inflammation has been lacking. Here we investigated the role of Ackr1 in chronic inflammation, in particular in the setting of atherogenesis, using the apolipoprotein E-deficient (ApoE(-/-)) mouse model. METHODS AND RESULTS: Ackr1(-/-)ApoE(-/-) and Ackr1(+/+)ApoE(-/-) littermates were obtained by crossing ApoE(-/-) mice and Ackr1(-/-) mice on a C57BL/6J background. Ackr1 (+/+)ApoE(-/-)mice fed a Western diet up-regulated Ackr1 expression in the aorta and had markedly increased atherosclerotic lesion size compared with Ackr1(-/-)ApoE(-/-) mice. This difference was observed in both the whole aorta and the aortic root in both early and late stages of the model. Ackr1 deficiency did not affect serum cholesterol levels or macrophage, collagen or smooth muscle cell content in atherosclerotic plaques, but significantly reduced the expression of Ccl2 and Cxcl1 in the whole aorta of ApoE(-/-) mice. In addition, Ackr1 deficiency resulted in a modest decrease in T cell subset frequency and inflammatory mononuclear phagocyte content in aorta and blood in the model. CONCLUSIONS: Ackr1 deficiency appears to be protective in the ApoE knockout model of atherogenesis, but it is associated with only modest changes in cytokine and chemokine expression as well as T-cell subset frequency and inflammatory macrophage content.
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Aorta , Aortitis , Apolipoproteínas E , Aterosclerosis , Receptores de Superficie Celular , Animales , Femenino , Traslado Adoptivo , Aorta/inmunología , Aorta/metabolismo , Aorta/patología , Aortitis/genética , Aortitis/inmunología , Aortitis/metabolismo , Aortitis/patología , Aortitis/prevención & control , Apolipoproteínas E/deficiencia , Apolipoproteínas E/genética , Aterosclerosis/genética , Aterosclerosis/inmunología , Aterosclerosis/metabolismo , Aterosclerosis/patología , Aterosclerosis/prevención & control , Moléculas de Adhesión Celular/metabolismo , Células Cultivadas , Quimiocina CCL2/metabolismo , Quimiocina CXCL1/metabolismo , Dieta Occidental , Modelos Animales de Enfermedad , Sistema del Grupo Sanguíneo Duffy/genética , Mediadores de Inflamación/metabolismo , Macrófagos/inmunología , Macrófagos/metabolismo , Ratones Endogámicos C57BL , Ratones Noqueados , Fenotipo , Placa Aterosclerótica , Receptores de Superficie Celular/deficiencia , Receptores de Superficie Celular/genética , Linfocitos T/inmunología , Linfocitos T/metabolismo , Linfocitos T/trasplante , Factores de TiempoRESUMEN
Congenital heart valve defects in humans occur in approximately 2% of live births and are a major source of compromised cardiac function. In this study we demonstrate that normal heart valve development and cardiac function are dependent upon Galnt1, the gene that encodes a member of the family of glycosyltransferases (GalNAc-Ts) responsible for the initiation of mucin-type O-glycosylation. In the adult mouse, compromised cardiac function that mimics human congenital heart disease, including aortic and pulmonary valve stenosis and regurgitation; altered ejection fraction; and cardiac dilation, was observed in Galnt1 null animals. The underlying phenotype is aberrant valve formation caused by increased cell proliferation within the outflow tract cushion of developing hearts, which is first detected at developmental stage E11.5. Developing valves from Galnt1 deficient animals displayed reduced levels of the proteases ADAMTS1 and ADAMTS5, decreased cleavage of the proteoglycan versican and increased levels of other extracellular matrix proteins. We also observed increased BMP and MAPK signaling. Taken together, the ablation of Galnt1 appears to disrupt the formation/remodeling of the extracellular matrix and alters conserved signaling pathways that regulate cell proliferation. Our study provides insight into the role of this conserved protein modification in cardiac valve development and may represent a new model for idiopathic valve disease.
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Embrión de Mamíferos/fisiopatología , Cardiopatías Congénitas/patología , Válvulas Cardíacas/fisiopatología , N-Acetilgalactosaminiltransferasas/genética , N-Acetilgalactosaminiltransferasas/metabolismo , Proteínas ADAM/metabolismo , Proteína ADAMTS1 , Proteína ADAMTS5 , Animales , Proliferación Celular , Modelos Animales de Enfermedad , Proteínas de la Matriz Extracelular/metabolismo , Cardiopatías Congénitas/genética , Cardiopatías Congénitas/fisiopatología , Válvulas Cardíacas/patología , Humanos , Sistema de Señalización de MAP Quinasas , Ratones , Polipéptido N-AcetilgalactosaminiltransferasaRESUMEN
Forty-two patients relapsing after an unmanipulated haploidentical BM transplant and post-transplant CY (PT-CY), were given 108 DLI, with median interval from transplant of 266 days (range, 67-1372). DLI were given at escalating doses, expressed as CD3+ cells/kg, without GVHD prophylaxis, and ranged from 1 × 10(3) to 1 × 10(7) cells/kg (median 5 × 10(5) cells/kg). The average number of DLI per patient was 2.6 (range, 1-6). The diagnosis was leukemias (n=32) grafted with a myeloablative regimen and Hodgkin's disease (n=10), grafted with a nonmyeloablative regimen. Leukemic patients with molecular relapse (n=20), received DLI alone (n=17) or in association with azacytidine (n=3); leukemic patients with hematologic relapse (n=12) received chemotherapy followed by DLI (n=11) or DLI alone (n=1); Hodgkin patients received DLI following 1-3 courses of chemotherapy. In these three groups the incidence of acute GVHD II-III was 15%, 17% and 10%; response rate was 45%, 33% and 70%; 2-year actuarial survival was 43%, 19% and 80% respectively. This study confirms that escalating doses of DLI can be given in the haploidentical setting with PT-CY, with a relatively low risk of acute GVHD. Response rates and survival are dependent on the underlying disease.
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Antimetabolitos Antineoplásicos/administración & dosificación , Azacitidina/administración & dosificación , Trasplante de Médula Ósea , Enfermedad Injerto contra Huésped/prevención & control , Enfermedad de Hodgkin , Leucemia , Transfusión de Linfocitos , Adolescente , Adulto , Anciano , Aloinjertos , Supervivencia sin Enfermedad , Enfermedad Injerto contra Huésped/mortalidad , Enfermedad de Hodgkin/mortalidad , Enfermedad de Hodgkin/prevención & control , Humanos , Leucemia/mortalidad , Leucemia/prevención & control , Donadores Vivos , Persona de Mediana Edad , Recurrencia , Tasa de Supervivencia , Factores de TiempoRESUMEN
INTRODUCTION: A mouse model of progeria derived by insertion of the human mutant LMNA gene (mLMNA), producing mutant lamin A, shows loss of smooth muscle cells in the media of the ascending aorta. We hypothesized that high shear stress, in the presence of mutant lamin A, induces this vasculopathy and tried to define the molecular and cellular basis for aortic vasculopathy. METHODS: Ascending and descending aortas from wild type (WT) and mLMNA+ mice were compared using proteomics, Western blots, PCR and immunostaining. To determine whether high fluidic shear stress, known to occur in the ascending aorta, contributed to the vasculopathy, we exposed descending aortas of mLMNA+ mice, with no apparent vasculopathy, to 75 dynes/cm2 shear stress for 30 minutes using a microfluidic system. RESULTS: When the mice were one year of age, expression of several mechanotransduction proteins in the ascending aorta, including vimentin, decreased in mLMNA+ mice but no decrease occurred in the descending aorta. High fluidic shear stress produced a significant reduction in vimentin of mLMNA+ mice but not in similarly treated WT mice. CONCLUSIONS: The occurrence of mutant lamin A and high shear stress correlate with a reduction in the level of mechanotransduction proteins in smooth muscle cells of the media. Reduction of these proteins may contribute over time to development of vasculopathy in the ascending aorta in progeria syndrome.
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Progeria/metabolismo , Progeria/patología , Enfermedades Vasculares/metabolismo , Enfermedades Vasculares/patología , Animales , Modelos Animales de Enfermedad , Expresión Génica , Humanos , Proteínas de Filamentos Intermediarios/metabolismo , Lamina Tipo A , Mecanotransducción Celular , Ratones , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/patología , Proteínas Nucleares/metabolismo , Precursores de Proteínas/metabolismo , Estrés MecánicoRESUMEN
Hard X-ray phase-contrast imaging characterizes the electron density distribution in an object without the need for radiation absorption. The power of phase contrast to resolve subtle changes, such as those in soft tissue structures, lies in its ability to detect minute refractive bending of X-rays. Here we report a far-field, two-arm interferometer based on the new nanometric phase gratings, which can detect X-ray refraction with subnanoradian sensitivity, and at the same time overcomes the fundamental limitation of ultra-narrow bandwidths (Δλ/λ~10â»4) of the current, most sensitive methods based on crystal interferometers. On a 1.5% bandwidth synchrotron source, we demonstrate clear visualization of blood vessels in unstained mouse organs in simple projection views, with over an order-of-magnitude higher phase contrast than current near-field grating interferometers.
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Vasos Sanguíneos/ultraestructura , Drosophila melanogaster/ultraestructura , Interferometría/instrumentación , Riñón/diagnóstico por imagen , Tomografía Computarizada por Rayos X/instrumentación , Animales , Interferometría/métodos , Riñón/irrigación sanguínea , Riñón/ultraestructura , Masculino , Ratones , Ratones Endogámicos C57BL , Sincrotrones , Tomografía Computarizada por Rayos X/métodos , Rayos XRESUMEN
Human LMNA gene mutations result in laminopathies that include Emery-Dreifuss muscular dystrophy (AD-EDMD) and Hutchinson-Gilford progeria, the premature aging syndrome (HGPS). The Lmna null (Lmna(-/-)) and progeroid LmnaΔ9 mutant mice are models for AD-EDMD and HGPS, respectively. Both animals develop severe tissue pathologies with abbreviated life spans. Like HGPS cells, Lmna(-/-) and LmnaΔ9 fibroblasts have typically misshapen nuclei. Unexpectedly, Lmna(-/-) or LmnaΔ9 mice that are also deficient for the inner nuclear membrane protein Sun1 show markedly reduced tissue pathologies and enhanced longevity. Concordantly, reduction of SUN1 overaccumulation in LMNA mutant fibroblasts and in cells derived from HGPS patients corrected nuclear defects and cellular senescence. Collectively, these findings implicate Sun1 protein accumulation as a common pathogenic event in Lmna(-/-), LmnaΔ9, and HGPS disorders.
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Lamina Tipo A/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas Asociadas a Microtúbulos/metabolismo , Distrofia Muscular de Emery-Dreifuss/metabolismo , Distrofia Muscular de Emery-Dreifuss/patología , Proteínas Nucleares/metabolismo , Progeria/metabolismo , Animales , Línea Celular , Senescencia Celular , Modelos Animales de Enfermedad , Fibroblastos/metabolismo , Humanos , Ratones , Ratones Noqueados , Proteínas Asociadas a Microtúbulos/genética , Progeria/patologíaRESUMEN
The muscle-specific protein NRAP is concentrated at cardiac intercalated disks, plays a role in myofibril assembly, and is upregulated early in mouse models of dilated cardiomyopathy. Using a tet-off system, we developed novel transgenic lines exhibiting cardiac-specific NRAP overexpression ~2.5 times greater than normal. At 40-50 weeks, NRAP overexpression resulted in dilation and decreased ejection fraction in the right ventricle, with little effect on the left ventricle. Expression of transcripts encoding brain natriuretic peptide and skeletal α-actin was increased by cardiac-specific NRAP overexpression, indicative of a cardiomyopathic response. NRAP overexpression did not alter the levels or organization of N-cadherin and connexin-43. The results show that chronic NRAP overexpression in the mouse leads to right ventricular cardiomyopathy by 10 months, but that the early NRAP upregulation previously observed in some mouse models of dilated cardiomyopathy is unlikely to account for the remodeling of intercalated disks and left ventricular dysfunction observed in those cases.
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Proteínas Musculares/metabolismo , Miocardio/metabolismo , Disfunción Ventricular Derecha/patología , Disfunción Ventricular Derecha/fisiopatología , Animales , Biomarcadores/metabolismo , Cardiomiopatía Dilatada/fisiopatología , Ecocardiografía , Imagen por Resonancia Magnética , Ratones , Ratones Transgénicos , Proteínas Musculares/genética , Miocardio/citología , Miocardio/patología , TransgenesRESUMEN
BACKGROUND: using a resolution 1000-fold higher than prior studies, we studied (1) the degree to which late gadolinium-enhancement (LGE) cardiac magnetic resonance tracks fibrosis from chronic myocardial infarction and (2) the relationship between intermediate signal intensity and partial volume averaging at distinct "smooth" infarct borders versus disorganized mixtures of fibrosis and viable cardiomyocytes. METHODS AND RESULTS: sprague-Dawley rats underwent myocardial infarction by coronary ligation. Two months later, rats were euthanized 10 minutes after administration of 0.3 mmol/kg intravenous gadolinium. LGE images ex vivo at 7 T with a 3D gradient echo sequence with 50×50×50 µm voxels were compared with histological sections (Masson trichrome). Planimetered histological and LGE regions of fibrosis correlated well (y=1.01x-0.01; R(2)=0.96; P<0.001). In addition, LGE images routinely detected clefts of viable cardiomyocytes 2 to 4 cells thick that separated bands of fibrous tissue. Although LGE clearly detected disorganized mixtures of fibrosis and viable cardiomyocytes characterized by intermediate signal intensity voxels, the percentage of apparent intermediate signal intensity myocardium increased significantly (P<0.01) when image resolution was degraded to resemble clinical resolution consistent with significant partial volume averaging. CONCLUSIONS: these data provide important validation of LGE at nearly the cellular level for detection of fibrosis after myocardial infarction. Although LGE can detect heterogeneous patches of fibrosis and viable cardiomyocytes as patches of intermediate signal intensity, the percentage of intermediate signal intensity voxels is resolution dependent. Thus, at clinical resolutions, distinguishing the peri-infarct border zone from partial volume averaging with LGE is challenging.
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Medios de Contraste , Gadolinio DTPA , Imagen por Resonancia Magnética/métodos , Infarto del Miocardio/patología , Enfermedad Aguda , Animales , Enfermedad Crónica , Fibrosis , Aumento de la Imagen/métodos , Procesamiento de Imagen Asistido por Computador/métodos , Imagenología Tridimensional/métodos , Masculino , Miocardio/patología , Miocardio/ultraestructura , Ratas , Ratas Sprague-Dawley , Reproducibilidad de los Resultados , Factores de TiempoRESUMEN
Rapid advances in medical imaging are facilitating the clinical assessment of first-trimester human embryos at increasingly earlier stages. To obtain data on early human development, we used magnetic resonance (MR) imaging and episcopic fluorescence capture (EFIC) to acquire digital images of human embryos spanning the time of dynamic tissue remodeling and organogenesis (Carnegie stages 13 to 23). These imaging data sets are readily resectioned digitally in arbitrary planes, suitable for rapid high-resolution three-dimensional (3D) observation. Using these imaging datasets, a web-accessible digital Human Embryo Atlas (http://apps.devbio.pitt.edu/humanatlas/) was created containing serial 2D images of human embryos in three standard histological planes: sagittal, frontal, and transverse. In addition, annotations and 3D reconstructions were generated for visualizing different anatomical structures. Overall, this Human Embryo Atlas is a unique resource that provides morphologic data of human developmental anatomy that can accelerate basic research investigations into developmental mechanisms that underlie human congenital anomalies.
Asunto(s)
Anatomía Artística , Atlas como Asunto , Primer Trimestre del Embarazo , Diagnóstico por Imagen , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética/métodos , EmbarazoRESUMEN
Despite promising preclinical data, the treatment of cardiovascular diseases using embryonic, bone-marrow-derived, and skeletal myoblast stem cells has not yet come to fruition within mainstream clinical practice. Major obstacles in cardiac stem cell investigations include the ability to monitor cell engraftment and survival following implantation within the myocardium. Several cellular imaging modalities, including reporter gene and MRI-based tracking approaches, have emerged that provide the means to identify, localize, and monitor stem cells longitudinally in vivo following implantation. This Review will examine the various cardiac cellular tracking modalities, including the combinatorial use of several probes in multimodality imaging, with a focus on data from the past 5 years.