RESUMEN
Neonatal hypoxia-ischemia (HI) is associated to cognitive and motor impairments and until the moment there is no proven treatment. The underlying neuroprotective mechanisms of stem cells are partially understood and include decrease in excitotoxicity, apoptosis and inflammation suppression. This study was conducted in order to test the effects of intracardiac transplantation of human dental pulp stem cells (hDPSCs) for treating HI damage. Seven-day-old Wistar rats were divided into four groups: sham-saline, sham-hDPSCs, HI-saline, and HI-hDPSCs. Motor and cognitive tasks were performed from postnatal day 30. HI-induced cognitive deficits in the novel-object recognition test and in spatial reference memory impairment which were prevented by hDPSCs. No motor impairments were observed in HI animals. Immunofluorescence analysis showed human-positive nuclei in hDPSC-treated animals closely associated with anti-GFAP staining in the lesion scar tissue, suggesting that these cells were able to migrate to the injury site and could be providing support to CNS cells. Our study evidence novel evidence that hDPSC can contribute to the recovery following hypoxia-ischemia and highlight the need of further investigation in order to better understand the exact mechanisms underlying its neuroprotective effects.
Asunto(s)
Disfunción Cognitiva/prevención & control , Pulpa Dental/trasplante , Hipoxia-Isquemia Encefálica/terapia , Trasplante de Células Madre/métodos , Animales , Animales Recién Nacidos , Células Cultivadas , Disfunción Cognitiva/etiología , Disfunción Cognitiva/patología , Pulpa Dental/citología , Pulpa Dental/fisiología , Femenino , Ventrículos Cardíacos , Humanos , Hipoxia-Isquemia Encefálica/complicaciones , Hipoxia-Isquemia Encefálica/patología , Inyecciones , Masculino , Aprendizaje por Laberinto/fisiología , Embarazo , Distribución Aleatoria , Ratas , Ratas Wistar , Células Madre/fisiologíaRESUMEN
The effects of neonatal hypoxia-ischemia (HI) on energy metabolism in male and female rats were investigated, testing the hypothesis that HI-induced brain mitochondrial dysfunction could present in a dimorphic pattern. Impairment in electron transport chain complex activities at 2 and 18 h after HI was observed in cortex and hippocampus in rats of both sexes, with females presenting an overall activity higher than that of males. Females also showed loss of mitochondrial mass and membrane potential 18 h after HI, while males were only slightly affected. These findings suggest a dimorphism in mitochondrial dysfunction and provide information that may lead to new neuroprotection strategies.
Asunto(s)
Corteza Cerebral/patología , Metabolismo Energético , Hipocampo/patología , Hipoxia/patología , Isquemia/patología , Mitocondrias/fisiología , Animales , Animales Recién Nacidos , Transporte de Electrón , Femenino , Masculino , Potencial de la Membrana Mitocondrial , Membranas Mitocondriales/fisiología , Embarazo , Ratas , Ratas Wistar , Factores SexualesRESUMEN
INTRODUCTION: The aim of this study was to isolate and grow cells from sound human deciduous teeth pulp with different levels of resorption and evaluate stem cell parameters. METHODS: Pulp tissue was removed from 30 different patients, aged from 6 to 12 years. From all the teeth, 21 were in advanced levels of resorption (group 1), and the remaining nine teeth did not show any visible resorption (group 2). Pulp tissue was removed and dissociated, and the suspension was seeded onto 12-well plates. The phenotype of the cells (n = 5) was analyzed on fifth and tenth passages by flow cytometry for clusters of differentiation (CD)29/PE, CD34/PE, CD44/FITC, CD45/FITC, CD90/FITC, CD117/PE, CD133/PE, CD146/FITC, CD184/PE, Stromal Cell Surface Marker 1 (STRO-1)/FITC and human leukocyte antigen major histocompatibility complex class II surface receptor (HLA-DR)/FITC, and by reverse transcription-polymerase chain reaction (RT-PCR) for octamer-binding transcription factor 4 (OCT-4). On the same passages, cells were differentiated into adipocytes, osteoblasts, and chondrocytes. RESULTS: Cell isolation was successful in 25 samples, but only 17 of these reached 90% confluence. It was not possible to establish cell culture from group 2. Cells on both fifth and tenth passages were positive for CD29, CD44, and CD90 and also for the expression of OCT-4. Moderate labeling was observed for CD117 and CD133, whereas a low expression was detected for CD34, CD45, HLA-DR, CD184, CD146, and STRO-1. All cultures differentiated into three cell types. CONCLUSIONS: The isolated pulp cells can be considered stem cells. The facility for obtaining cells seems to be related to the root resorption process, so, therefore, the cells from group 1 were able to proliferate in vitro, whereas group 2 cells were not.
Asunto(s)
Diferenciación Celular , Pulpa Dental/citología , Células Madre Pluripotentes Inducidas/citología , Resorción Radicular/clasificación , Diente Primario/citología , Biomarcadores/metabolismo , Separación Celular , Células Cultivadas , Niño , Pulpa Dental/fisiología , Citometría de Flujo , Humanos , Células Madre Pluripotentes Inducidas/clasificación , Células Madre Pluripotentes Inducidas/metabolismo , Raíz del Diente/fisiologíaRESUMEN
Heat shock protein 27 (HSP27) has a major role in mediating survival responses to a range of central nervous system insults, functioning as a protein chaperone, an antioxidant, and through inhibition of cell death pathways. We have used transgenic mice overexpressing HSP27 (HSP27tg) to examine the role of HSP27 in cerebral ischemia, using model of permanent middle cerebral artery occlusion (MCAO). Infarct size was evaluated using multislice T(2)-weighted anatomical magnetic resonance imaging (MRI) after 24 h. A significant reduction of 30% in infarct size was detected in HSP27tg animals compared with wild-type (WT) littermates. To gain some insight into the mechanisms contributing to cell death and its attenuation by HSP27, we monitored the effect of induction of c-jun and ATF3 on tissue survival in MCAO and their effects on the expression of endogenous mouse HSP25 and HSP70. It is important that, the c-jun induction seen at 4 h tended to be localized to regions that were salvageable in HSP27tg mice but became infarcted in WT animals. Our results provide support for the powerful neuroprotective effects of HSP27 in cerebral ischemia.
Asunto(s)
Isquemia Encefálica/metabolismo , Isquemia Encefálica/patología , Encéfalo , Proteínas de Choque Térmico HSP27/metabolismo , Fármacos Neuroprotectores/metabolismo , Factor de Transcripción Activador 3/genética , Factor de Transcripción Activador 3/metabolismo , Animales , Encéfalo/metabolismo , Encéfalo/patología , Infarto Cerebral/metabolismo , Infarto Cerebral/patología , Circulación Cerebrovascular/fisiología , Proteína Ácida Fibrilar de la Glía/genética , Proteína Ácida Fibrilar de la Glía/metabolismo , Proteínas HSP70 de Choque Térmico/metabolismo , Proteínas de Choque Térmico/metabolismo , Humanos , Hibridación in Situ , Infarto de la Arteria Cerebral Media/patología , Imagen por Resonancia Magnética , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Chaperonas Moleculares , Proteínas de Neoplasias/metabolismo , Proteínas Proto-Oncogénicas c-jun/genética , Proteínas Proto-Oncogénicas c-jun/metabolismo , Flujo Sanguíneo Regional/fisiologíaRESUMEN
Autophagy is known to be a feature of cardiomyopathies and chronic ischaemia. Here we demonstrate that autophagy is also induced by a single cycle of ischaemia/reperfusion (I/R in neonatal and adult rat cardiac myocytes). Consistent with the critical role for Beclin1 in autophagocytosis, reduction of Beclin1 expression in cardiac myocytes by RNAi reduces I/R-induced autophagy and this is associated with enhanced cell survival. Autophagy is also reduced by urocortin, an endogenous cardiac peptide which we have previously shown to reduce other forms of myocyte cell death induced by I/R. The inhibition of autophagy by urocortin is mediated in part by inhibition of Beclin1 expression, an effect which is mediated by activation of the PI3 kinase/Akt pathway but which does not involve activation of p42/p44 MAPK.
Asunto(s)
Proteínas Reguladoras de la Apoptosis/metabolismo , Autofagia/efectos de los fármacos , Hormona Liberadora de Corticotropina/farmacología , Daño por Reperfusión Miocárdica/inducido químicamente , Daño por Reperfusión Miocárdica/patología , Miocitos Cardíacos/citología , Miocitos Cardíacos/efectos de los fármacos , Animales , Animales Recién Nacidos , Beclina-1 , Supervivencia Celular/efectos de los fármacos , Expresión Génica , Miocitos Cardíacos/patología , Fosfatidilinositol 3-Quinasas/metabolismo , Ratas , UrocortinasRESUMEN
We investigated the importance of the phosphoinositide3-kinase (PI3K) pathway in CA1 and dentate gyrus (DG) areas of hippocampus by exposing organotypic cultures to LY294002, a PI3K inhibitor, or to oxygen and glucose deprivation (OGD) for up to 21 hours. LY294002 induced increased propidium iodide (PI) uptake and caspase 3/7 activity in both regions, with a faster onset in DG. In contrast, cultures exposed to 60 min of OGD showed a PI uptake only in the CA1 area, beginning 13 h after the insult and increasing until 21 h. We did not observe any significant changes in AKT phosphorylation and immunocontent in CA1 or DG areas of organotypic cultures exposed to OGD, suggesting that the phosphorylation of this protein at Ser-473 is unrelated to the cellular damage induced by ischemia. Our results suggest that the inhibition of the PI3K pathway does not mimic the cell death profile observed with an ischemic model.
Asunto(s)
Inhibidores Enzimáticos/farmacología , Glucosa/deficiencia , Hipocampo/patología , Hipoxia/patología , Inhibidores de las Quinasa Fosfoinosítidos-3 , Transducción de Señal/efectos de los fármacos , Animales , Apoptosis/efectos de los fármacos , Western Blotting , Caspasas/metabolismo , Muerte Celular/efectos de los fármacos , Células Cultivadas , Cromonas/farmacología , Activación Enzimática/efectos de los fármacos , Morfolinas/farmacología , Proteína Oncogénica v-akt , Fosforilación , Ratas , Ratas Wistar , Proteínas Oncogénicas de Retroviridae/fisiologíaRESUMEN
Heat shock proteins (HSPs) have been reported to increase cell survival in response to a wide range of cellular challenges. However, the role of HSP70 overexpression is still a matter of debate, with some reports showing protection and others not. In order to resolve these discrepancies and further investigate the action of these proteins in vivo, transgenic mice overexpressing HSP70 have been compared to wild-type mice in a middle cerebral artery occlusion model of permanent cerebral ischaemia. Previously, the effect of HSP70 was assessed histologically postmortem. In this report, magnetic resonance imaging (MRI) was used to assess the mice in vivo after the onset of stroke. The lesion volume, as measured at 24 h using T(2)-weighted MRI, was significantly smaller in HSP70 transgenic mice compared with wild-type mice. The smaller lesion size in HSP70 transgenic mice could not be attributed to differences in vascular anatomy or in cerebral blood flow during occlusion. Additionally, the apparent diffusion coefficient showed different spatial and temporal patterns between the groups, suggesting that the damage within the lesion may be less severe for HSP70 transgenic mice. Thus, we conclude that overexpression of HSP70 reduces the overall lesion size and may also limit the tissue damage within the lesion.