Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
1.
bioRxiv ; 2024 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-39229198

RESUMO

To enhance early diagnosis and treatment of Alzheimer·s disease (AD), understanding the pathological changes before symptoms arise is crucial. The continuum model of AD suggest that Aß beta (Aß) accumulation precedes symptoms by at least 15 years, with vascular changes detectable around this time. Disturbances in capillary flow dynamics have been linked to reduced oxygen delivery to brain tissue, but evidence in presymptomatic AD remains elusive. We examined capillary flow dynamics in presymptomatic Tg-SwDI mice and the capacity of carbonic anhydrase inhibitors (CAIs) to prevent capillary flow disturbances. Our study revealed capillary flow disturbances associated with alterations in capillary morphology, adhesion molecule expression, and Aß load in cognitively normal 9-10-month-old Tg-SwDI mice. Treated mice showed ameliorated capillary flow disturbances, enhanced oxygen availability, and reduced Aß load. These findings underscore the importance of capillary flow disturbances in presymptomatic AD and highlight CAIs· potential for preserving vascular integrity in early AD.

2.
Stud Health Technol Inform ; 310: 735-739, 2024 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-38269906

RESUMO

High-resolution whole slide image scans of histopathology slides have been widely used in recent years for prediction in cancer. However, in some cases, clinical informatics practitioners may only have access to low-resolution snapshots of histopathology slides, not high-resolution scans. We evaluated strategies for training neural network prognostic models in non-small cell lung cancer (NSCLC) based on low-resolution snapshots, using data from the Veterans Affairs Precision Oncology Data Repository. We compared strategies without transfer learning, with transfer learning from general domain images, and with transfer learning from publicly available high-resolution histopathology scans. We found transfer learning from high-resolution scans achieved significantly better performance than other strategies. Our contribution provides a foundation for future development of prognostic models in NSCLC that incorporate data from low-resolution pathology slide snapshots alongside known clinical predictors.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Informática Médica , Humanos , Carcinoma Pulmonar de Células não Pequenas/diagnóstico por imagem , Neoplasias Pulmonares/diagnóstico por imagem , Medicina de Precisão , Aprendizado de Máquina
3.
J Am Heart Assoc ; 11(9): e023918, 2022 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-35470685

RESUMO

Background Vascular function is compromised in Alzheimer disease (AD) years before amyloid and tau pathology are detected and a substantial body of work shows abnormal platelet activation states in patients with AD. The aim of our study was to investigate whether platelet function in middle age is independently associated with future risk of AD. Methods and Results We examined associations of baseline platelet function with incident dementia risk in the community-based FHS (Framingham Heart Study) longitudinal cohorts. The association between platelet function and risk of dementia was evaluated using the cumulative incidence function and inverse probability weighted Cox proportional cause-specific hazards regression models, with adjustment for demographic and clinical covariates. Platelet aggregation response was measured by light transmission aggregometry. The final study sample included 1847 FHS participants (average age, 53.0 years; 57.5% women). During follow-up (median, 20.5 years), we observed 154 cases of incident dementia, of which 121 were AD cases. Results from weighted models indicated that platelet aggregation response to adenosine diphosphate 1.0 µmol/L was independently and positively associated with dementia risk, and it was preceded in importance only by age and hypertension. Sensitivity analyses showed associations with the same directionality for participants defined as adenosine diphosphate hyper-responders, as well as the platelet response to 0.1 µmol/L epinephrine. Conclusions Our study shows individuals free of antiplatelet therapy with a higher platelet response are at higher risk of dementia in late life during a 20-year follow-up, reinforcing the role of platelet function in AD risk. This suggests that platelet phenotypes may be associated with the rate of dementia and potentially have prognostic value.


Assuntos
Doença de Alzheimer , Testes de Função Plaquetária , Difosfato de Adenosina , Doença de Alzheimer/epidemiologia , Feminino , Humanos , Estudos Longitudinais , Masculino , Agregação Plaquetária , Fatores de Risco
4.
Alzheimers Dement ; 18(6): 1248-1259, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-34569707

RESUMO

INTRODUCTION: Tumor necrosis factor (TNF) inhibitors are widely used to treat rheumatoid arthritis (RA) and their potential to retard Alzheimer's disease (AD) progression has been reported. However, their long-term effects on the dementia/AD risk remain unknown. METHODS: A propensity scored matched retrospective cohort study was conducted among 40,207 patients with RA within the US Veterans Affairs health-care system from 2000 to 2020. RESULTS: A total of 2510 patients with RA prescribed TNF inhibitors were 1:2 matched to control patients. TNF inhibitor use was associated with reduced dementia risk (hazard ratio [HR]: 0.64, 95% confidence interval [CI]: 0.52-0.80), which was consistent as the study period increased from 5 to 20 years after RA diagnosis. TNF inhibitor use also showed a long-term effect in reducing the risk of AD (HR: 0.57, 95% CI: 0.39-0.83) during the 20 years of follow-up. CONCLUSION: TNF inhibitor use is associated with lower long-term risk of dementia/AD among US veterans with RA.


Assuntos
Antirreumáticos , Artrite Reumatoide , Demência , Veteranos , Antirreumáticos/efeitos adversos , Artrite Reumatoide/complicações , Artrite Reumatoide/tratamento farmacológico , Artrite Reumatoide/epidemiologia , Demência/induzido quimicamente , Demência/epidemiologia , Demência/prevenção & controle , Humanos , Pontuação de Propensão , Estudos Retrospectivos , Inibidores do Fator de Necrose Tumoral
5.
Front Aging Neurosci ; 13: 773984, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34916927

RESUMO

Objective: Active neutrophils are important contributors to Alzheimer's disease (AD) pathology through the formation of capillary stalls that compromise cerebral blood flow (CBF) and through aberrant neutrophil signaling that advances disease progression. The neutrophil to lymphocyte ratio (NLR) is a proxy of neutrophil-mediated inflammation, and higher NLR is found in persons diagnosed with clinical AD. The objective of this study was to investigate whether increased NLR in older adults is independently associated with the risk of subsequent dementia. Methods: We examined associations of baseline NLR with incident dementia risk in the community-based Framingham Heart Study (FHS) longitudinal cohorts. The association between NLR and risk of dementia was evaluated using the cumulative incidence function (CIF) and inverse probability-weighted Cox proportional cause-specific hazards regression models, with adjustment for age, sex, body mass index (BMI), systolic and diastolic blood pressure, diabetes, current smoking status, low-density lipoprotein (LDH), high-density lipoprotein (LDL), total cholesterol, triglycerides, and history of cardiovascular disease (CVD). Random forest survival models were used to evaluate the relative predictive value of the model covariates on dementia risk. Results: The final study sample included 1,648 participants with FHS (average age, 69 years; 56% women). During follow-up (median, 5.9 years), we observed 51 cases of incident dementia, of which 41 were AD cases. Results from weighted models suggested that the NLR was independently associated with incident dementia, and it was preceded in predictive value only by age, history of CVD, and blood pressure at baseline. Conclusion: Our study shows that individuals with higher NLR are at a greater risk of subsequent dementia during a 5.9-year follow-up period. Further evaluating the role of neutrophil-mediated inflammation in AD progression may be warranted.

6.
Semin Oncol ; 46(4-5): 327-333, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31708233

RESUMO

BACKGROUND: There is wide interest in developing prognostic models in non-small-cell lung cancer (NSCLC) due to the heterogeneity of the disease. Models developed at other healthcare institutions may not be directly applicable for patients treated at the Department of Veterans Affairs (VA). External validation of a candidate prognostic model among VA patients would be crucial before it can be implemented to aid clinical decision-making. METHODS: A prognostic model for mortality developed in the Military Health System (MHS) was applied to data from the VA Precision Oncology Data Repository (VA-PODR), which is available to researchers inside and outside the VA at the Veterans Precision Oncology Data Commons (VPODC). Measures of discrimination and calibration were calculated for the MHS model. The MHS model was also refitted in VA-PODR data using the same risk factors to compare the effect of specific factors and predictive performance when the model is developed using VA data. RESULTS: Time-dependent AUC of the MHS prognostic model was 0.788, 0.806, 0.780, and 0.779 for predicting survival at 1, 2, 3, and 5 years following diagnosis, respectively. Significant discrepancies were found between predicted and observed rates of survival, particularly for later years. When the model is refit in VA-PODR data, it achieved cross-validated AUCs of 0.739, 0.773, 0.769, and 0.807 at the same time points, and discrepancies between predicted and observed survival were reduced. CONCLUSIONS: Validation of the MHS prognostic model in VA-PODR demonstrates that its discrimination remains strong when applied to VA patients. Nevertheless, further calibration to VA data may be needed to improve its risk estimation performance. This study highlights the utility of VA-PODR and the VPODC as a national resource for developing analytic tools that are well adapted to the Veteran population.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/mortalidade , Saúde dos Veteranos/estatística & dados numéricos , Veteranos , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma Pulmonar de Células não Pequenas/diagnóstico , Carcinoma Pulmonar de Células não Pequenas/epidemiologia , Carcinoma Pulmonar de Células não Pequenas/terapia , Feminino , Seguimentos , Humanos , Masculino , Oncologia , Pessoa de Meia-Idade , Mortalidade , Medicina de Precisão , Prognóstico , Curva ROC , Reprodutibilidade dos Testes , Fatores de Risco , Estados Unidos/epidemiologia
7.
PLoS One ; 13(9): e0202590, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30231069

RESUMO

Extracellular vesicles (EVs) have emerged as important mediators of intercellular communication and as possible therapeutic agents in inflammation-mediated demyelinating diseases, including multiple sclerosis (MS). In the present study, we investigated whether intravenously administered EVs derived from mesenchymal stem cells (MSCs) from human adipose tissue might mediate recovery in Theiler's murine encephalomyelitis virus (TMEV)-induced demyelinating disease, a progressive model of MS. SJL/J mice were subjected to EV treatment once the disease was established. We found that intravenous EV administration improved motor deficits, reduced brain atrophy, increased cell proliferation in the subventricular zone and decreased inflammatory infiltrates in the spinal cord in mice infected with TMEV. EV treatment was also capable of modulating neuroinflammation, given glial fibrillary acidic protein and Iba-1 staining were reduced in the brain, whereas myelin protein expression was increased. Changes in the morphology of microglial cells in the spinal cord suggest that EVs also modulate the activation state of microglia. The clear reduction in plasma cytokine levels, mainly in the Th1 and Th17 phenotypes, in TMEV mice treated with EVs confirms the immunomodulatory ability of intravenous EVs. According to our results, EV administration attenuates motor deficits through immunomodulatory actions, diminishing brain atrophy and promoting remyelination. Further studies are necessary to establish EV delivery as a possible therapy for the neurodegenerative phase of MS.


Assuntos
Vesículas Extracelulares/transplante , Células-Tronco Mesenquimais/citologia , Esclerose Múltipla/terapia , Theilovirus/patogenicidade , Tecido Adiposo/citologia , Administração Intravenosa , Animais , Proteínas de Ligação ao Cálcio/metabolismo , Proliferação de Células , Modelos Animais de Doenças , Regulação da Expressão Gênica , Proteína Glial Fibrilar Ácida/metabolismo , Humanos , Camundongos , Proteínas dos Microfilamentos/metabolismo , Esclerose Múltipla/imunologia , Esclerose Múltipla/virologia , Proteínas da Mielina/metabolismo , Resultado do Tratamento
8.
Transl Stroke Res ; 7(5): 378-87, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27384771

RESUMO

Cell-based therapy has demonstrated safety and efficacy in experimental animal models of stroke, as well as safety in stroke patients. However, various questions remain regarding the therapeutic window, dosage, route of administration, and the most appropriate cell type and source, as well as mechanisms of action and immune-modulation to optimize treatment based on stem cell therapy. Various delivery routes have been used in experimental stroke models, including intracerebral, intraventricular, subarachnoid, intra-arterial, intraperitoneal, intravenous, and intranasal routes. From a clinical point of view, it is necessary to demonstrate which is the most feasible, safest, and most effective for use with stroke patients. Therefore, further experimental studies concerning the safety, efficacy, and mechanisms of action involved in these therapeutic effects are required to determine their optimal clinical use.


Assuntos
Terapia Baseada em Transplante de Células e Tecidos/métodos , Células-Tronco/fisiologia , Acidente Vascular Cerebral/terapia , Animais , Humanos , Transplante de Células-Tronco
9.
Biomaterials ; 100: 41-52, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27240161

RESUMO

Ultrasound-targeted microbubble destruction (UTMD) has been shown to be a promising tool to deliver proteins to select body areas. This study aimed to analyze whether UTMD was able to deliver brain-derived neurotrophic factor (BDNF) to the brain, enhancing functional recovery and white matter repair, in an animal model of subcortical stroke induced by endothelin (ET)-1. UTMD was used to deliver BDNF to the brain 24 h after stroke. This technique was shown to be safe, given there were no cases of hemorrhagic transformation or blood brain barrier (BBB) leakage. UTMD treatment was associated with increased brain BDNF levels at 4 h after administration. Targeted ultrasound delivery of BDNF improved functional recovery associated with fiber tract connectivity restoration, increasing oligodendrocyte markers and remyelination compared to BDNF alone administration in an experimental animal model of white matter injury.


Assuntos
Fator Neurotrófico Derivado do Encéfalo/administração & dosagem , Encéfalo/efeitos dos fármacos , Sistemas de Liberação de Medicamentos/métodos , Microbolhas , Acidente Vascular Cerebral/tratamento farmacológico , Ultrassom/métodos , Substância Branca/efeitos dos fármacos , Animais , Encéfalo/patologia , Fator Neurotrófico Derivado do Encéfalo/farmacocinética , Fator Neurotrófico Derivado do Encéfalo/uso terapêutico , Linhagem Celular , Masculino , Oligodendroglia/efeitos dos fármacos , Oligodendroglia/patologia , Ratos Sprague-Dawley , Acidente Vascular Cerebral/patologia , Ondas Ultrassônicas , Substância Branca/patologia
10.
Stem Cell Res Ther ; 6: 121, 2015 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-26088123

RESUMO

INTRODUCTION: Despite its high incidence, nerve fiber (axon and myelin) damage after cerebral infarct has not yet been extensively investigated. The aim of this study was to investigate white matter repair after adipose-derived mesenchymal stem cell (ADMSC) administration in an experimental model of subcortical stroke. Furthermore, we aimed to analyze the ADMSC secretome and whether this could be implicated in this repair function. METHODS: An animal model of subcortical ischemic stroke with white matter affectation was induced in rats by injection of endothelin-1. At 24 hours, 2 × 10(6) ADMSC were administered intravenously to the treatment group. Functional evaluation, lesion size, fiber tract integrity, cell death, proliferation, white matter repair markers (Olig-2, NF, and MBP) and NogoA were all studied after sacrifice (7 days and 28 days). ADMSC migration and implantation in the brain as well as proteomics analysis and functions of the secretome were also analyzed. RESULTS: Neither ADMSC migration nor implantation to the brain was observed after ADMSC administration. In contrast, ADMSC implantation was detected in peripheral organs. The treatment group showed a smaller functional deficit, smaller lesion area, less cell death, more oligodendrocyte proliferation, more white matter connectivity and higher amounts of myelin formation. The treated animals also showed higher levels of white matter-associated markers in the injured area than the control group. Proteomics analysis of the ADMSC secretome identified 2,416 proteins, not all of them previously described to be involved in brain plasticity. CONCLUSIONS: White matter integrity in subcortical stroke is in part restored by ADMSC treatment; this is mediated by repair molecular factors implicated in axonal sprouting, remyelination and oligodendrogenesis. These findings are associated with improved functional recovery after stroke.


Assuntos
Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais/citologia , Acidente Vascular Cerebral/terapia , Substância Branca/fisiopatologia , Animais , Apoptose , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Diferenciação Celular , Movimento Celular , Proliferação de Células , Imagem de Tensor de Difusão , Modelos Animais de Doenças , Endotelina-1/toxicidade , Imageamento por Ressonância Magnética , Masculino , Proteína Básica da Mielina/metabolismo , Proteínas da Mielina/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Proteínas Nogo , Fator de Transcrição 2 de Oligodendrócitos , Oligodendroglia/citologia , Oligodendroglia/metabolismo , Proteoma/análise , Proteômica , Ratos , Ratos Sprague-Dawley , Recuperação de Função Fisiológica , Acidente Vascular Cerebral/etiologia
11.
Expert Opin Biol Ther ; 15(6): 873-81, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25959243

RESUMO

INTRODUCTION: Based on the positive results observed in experimental animal models, adipose tissue-derived mesenchymal stem cells (AD-MSCs) constitute a promising therapy for stroke treatment. However, several aspects need to be clarified to identify the optimal conditions for successful clinical translation. AREAS COVERED: This review focuses on AD-MSC treatment for ischemic and hemorrhagic stroke in experimental animal models. In addition, we will explore the optimization of treatment conditions including AD-MSC production, administration routes and therapeutic windows for their appropriate use in patients. Finally we will provide an update on clinical trials on this therapy. EXPERT OPINION: Compared with other cell types, AD-MSCs have been less investigated in stroke studies. Currently, experimental animal models have shown safety and efficacy with this treatment after stroke. Due to several advantages of AD-MSCs, such as their abundance and accessibility, they can be considered a promising strategy for use in patients. However, many questions are still to be resolved regarding their mechanisms of action, immune system modulation and the effects of AD-MSCs on all components of the brain that may be affected after ischemic and hemorrhagic strokes.


Assuntos
Tecido Adiposo/transplante , Transplante de Células-Tronco Mesenquimais/tendências , Células-Tronco Mesenquimais , Recuperação de Função Fisiológica , Acidente Vascular Cerebral/terapia , Tecido Adiposo/citologia , Animais , Encéfalo/patologia , Humanos , Transplante de Células-Tronco Mesenquimais/métodos , Células-Tronco Mesenquimais/fisiologia , Acidente Vascular Cerebral/diagnóstico
12.
Cerebrovasc Dis ; 39(5-6): 293-301, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25895451

RESUMO

BACKGROUND: After acute ischemia, the tissue that is at risk of infarction can be detected by perfusion-weighted imaging/diffusion-weighted imaging (PWI/DWI) mismatch but the time that is needed to process PWI limits its use. As DWI is highly sensitive to acute ischemic tissue damage, we hypothesized that different ADC patterns represent areas with a different potential for recovery. METHODS: In a model of permanent middle cerebral artery occlusion (pMCAO), Sprague-Dawley rats were randomly distributed to sham surgery and pMCAO. We further separated the pMCAO group according to intralesional ADC pattern (homogeneous or heterogeneous). At 24 h after ischemia induction, we analyzed lesion size, functional outcome, cell death expression, and brain protection markers including ROS enzyme NOX-4. MRI included DWI (ADC maps), DTI (tractography), and PWI (CBF, CBV and MTT). RESULTS: The lesion size was similar in pMCAO rats. Animals with a heterogeneous pattern in ADC maps showed better functional outcome in Rotarod test (p = 0.032), less expression of cell death (p = 0.014) and NOX-4 (p = 0.0063), higher intralesional CBF (p = 0.0026) and larger PWI/DWI mismatch (p = 0.007). CONCLUSIONS: In a rodent model for ischemic stroke, intralesional heterogeneity in ADC maps was related to better functional outcome in lesions of similar size and interval after pMCAO. DWI ADC maps may assist in the early identification of ischemic tissue with an increased potential for recovery as higher expression of acute protection markers, lower expression of cell death, increased PWI/DWI mismatch, and higher intralesional CBF were present in animals with a heterogeneous ADC pattern.


Assuntos
Isquemia Encefálica/patologia , Imagem de Difusão por Ressonância Magnética , Infarto da Artéria Cerebral Média/patologia , Acidente Vascular Cerebral/patologia , Envelhecimento , Animais , Circulação Cerebrovascular/fisiologia , Imagem de Difusão por Ressonância Magnética/métodos , Modelos Animais de Doenças , Masculino , Imagem de Perfusão/métodos , Ratos Sprague-Dawley , Acidente Vascular Cerebral/fisiopatologia
13.
J Transl Med ; 13: 46, 2015 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-25637958

RESUMO

BACKGROUND: Rat adipose tissue-derived-mesenchymal stem cells (rAD-MSCs) have proven to be safe in experimental animal models of stroke. However, in order to use human AD-MSCs (hAD-MSCs) as a treatment for stroke patients, a proof of concept is needed. We analyzed whether the xenogeneic hAD-MSCs were as safe and effective as allogeneic rAD-MSCs in permanent Middle Cerebral Artery Occlusion (pMCAO) in rats. METHODS: Sprague-Dawley rats were randomly divided into three groups, which were intravenously injected with xenogeneic hAD-MSCs (2 × 10(6)), allogeneic rAD-MSCs (2 × 10(6)) or saline (control) at 30 min after pMCAO. Behavior, cell implantation, lesion size and cell death were evaluated. Brain markers such as GFAP (glial fibrillary acid protein), VEGF (vascular endothelial growth factor) and SYP (synaptophysin) and tumor formation were analyzed. RESULTS: Compared to controls, recovery was significantly better at 24 h and continued to be so at 14 d after IV administration of either hAD-MSCs or rAD-MSCs. No reduction in lesion size or migration/implantation of cells in the damaged brain were observed in the treatment groups. Nevertheless, cell death was significantly reduced with respect to the control group in both treatment groups. VEGF and SYP levels were significantly higher, while those of GFAP were lower in the treated groups. At three months, there was no tumor formation. CONCLUSIONS: hAD-MSCs and rAD-MSCs were safe and without side effects or tumor formation. Both treatment groups showed equal efficacy in terms of functional recovery and decreased ischemic brain damage (cell death and glial scarring) and resulted in higher angiogenesis and synaptogenesis marker levels.


Assuntos
Tecido Adiposo/citologia , Infarto Cerebral/terapia , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais/citologia , Transplante Heterólogo , Doença Aguda , Animais , Biomarcadores/metabolismo , Morte Celular , Infarto Cerebral/complicações , Infarto Cerebral/fisiopatologia , Humanos , Infarto da Artéria Cerebral Média/complicações , Infarto da Artéria Cerebral Média/fisiopatologia , Masculino , Ratos Sprague-Dawley , Distribuição Tecidual , Transplante Homólogo
14.
J Neurosci Res ; 93(5): 806-14, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25524827

RESUMO

Angiotensin type 1 receptor blockers (ARBs) have induced improved functional recovery and reduced infarct volume in experimental animal models of stroke. Clinical data have indicated a positive correlation between prestroke treatment with ARBs and reduced stroke severity and better outcomes; however, the mechanisms of these beneficial effects are not yet well understood. This study compares the protective and possible reparative effects of continuous oral treatment with olmesartan (OLM) with OLM pretreatment and withdrawal after permanent middle cerebral artery occlusion (pMCAO) in rats. Fifty-two Sprague-Dawley rats were randomly assigned to five groups: MCAO(-/OLM) (OLM 10 mg/kg/day for 14 days after infarct), MCAO(OLM/OLM) (OLM 10 mg/kg/day for 7 days before and 14 days after infarct), MCAO(OLM/-) (OLM 10 mg/kg/day for 7 days before infarct), sham, and control. We analyzed functional recovery; lesion size; cell death; expression of the pro-oxidant enzyme NADPH oxidase 4 (NOX-4); isolectin-B4; and repair markers such as glial fibrillary acidic protein, vascular endothelial growth factor (VEGF), and brain-derived neurotrophic factor (BDNF). All of the OLM-treated groups showed significantly better functional scores and reduced infarct sizes and cell death compared with the control group 14 days after pMCAO. Levels of NOX-4, VEGF, and BDNF were significantly lower in the brains of the MCAO(OLM/OLM) and sham groups compared with the other groups. OLM treatment improved functional recovery and reduced lesion size and cell death after cerebral ischemia. Only the continuous administration of OLM before and after stroke reduced oxidative stress levels, with better tissue preservation, without triggering brain repair marker activation.


Assuntos
Bloqueadores do Receptor Tipo 1 de Angiotensina II/administração & dosagem , Imidazóis/administração & dosagem , Acidente Vascular Cerebral/tratamento farmacológico , Tetrazóis/administração & dosagem , Animais , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Modelos Animais de Doenças , Método Duplo-Cego , Esquema de Medicação , Feminino , Proteína Glial Fibrilar Ácida/metabolismo , Marcação In Situ das Extremidades Cortadas , Imageamento por Ressonância Magnética , Masculino , NADPH Oxidase 4 , NADPH Oxidases/metabolismo , Ratos , Ratos Sprague-Dawley , Índice de Gravidade de Doença , Estatísticas não Paramétricas , Acidente Vascular Cerebral/patologia , Fatores de Tempo , Fator A de Crescimento do Endotélio Vascular/metabolismo
15.
Stroke ; 46(1): 221-8, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25395417

RESUMO

BACKGROUND AND PURPOSE: Translational research is beginning to reveal the importance of trophic factors as a therapy for cellular brain repair. The purpose of this study was to analyze whether brain-derived neurotrophic factor (BDNF) administration could mediate oligodendrogenesis and remyelination after white matter injury in subcortical stroke. METHODS: Ischemia was induced in rats by injection of endothelin-1. At 24 hours, 0.4 µg/kg of BDNF or saline was intravenously administered to the treatment and control groups, respectively. Functional evaluation, MRI, and fiber tract integrity on tractography images were analyzed. Proliferation (KI-67) and white matter repair markers (A2B5, 2',3'-cyclic-nucleotide 3'-phosphodiesterase [CNPase], adenomatous polyposis coli [APC], platelet-derived growth factor receptor alpha [PDGFR-α], oligodendrocyte marker O4 [O4], oligodendrocyte transcription factor [Olig-2], and myelin basic protein [MBP]) were analyzed at 7 and 28 days. RESULTS: The BDNF-treated animals showed less functional deficit at 28 days after treatment than the controls (P<0.05). Although T2-MRI did not show differences in lesion size at 7 and 28 days between groups, diffusion tensor imaging tractography analysis revealed significantly better tract connectivity at 28 days in the BDNF group than in the controls (P<0.05). Increased proliferation of oligodendrocyte progenitors was observed in treated animals at 7 days (P<0.05). Finally, the levels of white matter repair markers (A2B5, CNPase, and O4 at 7 days; Olig-2 and MBP at 28 days) were higher in the BDNF group than in the controls (P<0.05). CONCLUSIONS: BDNF administration exerted better functional outcome, oligodendrogenesis, remyelination, and fiber connectivity than controls in rats subjected to subcortical damage in ischemic stroke.


Assuntos
Isquemia Encefálica/patologia , Fator Neurotrófico Derivado do Encéfalo/farmacologia , Diferenciação Celular/efeitos dos fármacos , Bainha de Mielina/efeitos dos fármacos , Oligodendroglia/efeitos dos fármacos , Acidente Vascular Cerebral/patologia , Substância Branca/efeitos dos fármacos , 2',3'-Nucleotídeo Cíclico Fosfodiesterases/efeitos dos fármacos , Proteína da Polipose Adenomatosa do Colo/efeitos dos fármacos , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Encéfalo/patologia , Isquemia Encefálica/complicações , Imagem de Tensor de Difusão , Imageamento por Ressonância Magnética , Proteína Básica da Mielina/efeitos dos fármacos , Bainha de Mielina/patologia , Bainha de Mielina/fisiologia , Ratos , Receptor alfa de Fator de Crescimento Derivado de Plaquetas/efeitos dos fármacos , Acidente Vascular Cerebral/etiologia , Substância Branca/patologia
16.
Discov Med ; 16(86): 37-43, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23911230

RESUMO

More recently, growing interests have brought cell therapy to the forefront of promising new approaches towards efficacious treatment for stroke. Of all cell-types, adipose tissue-derived mesenchymal stem cells (AD-MSC) are considered good candidates for stroke treatment because of their abundance and easy harvesting without invasive surgery from healthy donors. A wide number of experimental studies have demonstrated the potential of AD-MSC administration for improving functional deficits and have led to the first clinical trials in stroke patients. Trophic factor release and paracrine interactions, transdifferentiation potential, and immunomodulatory effects have all been cited as the main functional mechanisms involved in AD-MSC therapy. These properties make AD-MSC therapy of special interest in fomenting the enhancement of natural brain repair mechanisms such as neurogenesis, gliagenesis, oligodendrogenesis, axonal sprouting, nerve repair, and angiogenesis. This review will focus on studies showing promising results of AD-MSC in stroke treatment.


Assuntos
Tecido Adiposo/citologia , Encéfalo/patologia , Transplante de Células-Tronco Mesenquimais/métodos , Acidente Vascular Cerebral/terapia , Animais , Humanos , Neurogênese , Resultado do Tratamento
17.
Expert Opin Biol Ther ; 13(11): 1479-83, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23915288

RESUMO

INTRODUCTION: Stroke is a major worldwide cause of death and disability. Currently, intravenous thrombolysis and reperfusion therapies, but not the so-called neuroprotectant drugs, have been shown to be effective for acute ischemic stroke. Thus, new strategies to promote brain plasticity are necessary. Stem cell administration is an attractive future therapeutic approach. AREAS COVERED: Brain protection and repair mechanisms are activated after stroke. This article is focused on the capacity of stem cell-based therapy to enhance this postinfarct brain plasticity and recovery. Future therapeutic considerations and prospects for stroke are discussed. EXPERT OPINION: Although cell therapy is promising in stroke treatment, mechanisms of action need to be characterized in detail. Further, the different mechanisms of axonal plasticity and remodeling involucrated in brain repair, not only in the gray but also in white matter, must be investigated through noninvasive techniques, and a multidisciplinary approach is fundamental in this.


Assuntos
Transplante de Células-Tronco , Acidente Vascular Cerebral/cirurgia , Proteínas Angiogênicas/metabolismo , Animais , Isquemia Encefálica/tratamento farmacológico , Isquemia Encefálica/cirurgia , Movimento Celular , Terapia Combinada , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Transplante de Células-Tronco Mesenquimais/métodos , Células-Tronco Mesenquimais/metabolismo , Bainha de Mielina/fisiologia , Neovascularização Fisiológica , Fatores de Crescimento Neural/metabolismo , Neurogênese , Neuroglia/fisiologia , Plasticidade Neuronal , Ratos , Regeneração , Reabilitação do Acidente Vascular Cerebral , Terapia Trombolítica , Pesquisa Translacional Biomédica
18.
Stem Cell Res Ther ; 4(1): 11, 2013 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-23356495

RESUMO

INTRODUCTION: Stem cell therapy can promote good recovery from stroke. Several studies have demonstrated that mesenchymal stem cells (MSC) are safe and effective. However, more information regarding appropriate cell type is needed from animal model. This study was targeted at analyzing the effects in ischemic stroke of acute intravenous (i.v.) administration of allogenic bone marrow- (BM-MSC) and adipose-derived-stem cells (AD-MSC) on functional evaluation results and brain repair markers. METHODS: Allogenic MSC (2 × 106 cells) were administered intravenously 30 minutes after permanent middle cerebral artery occlusion (pMCAO) to rats. Infarct volume and cell migration and implantation were analyzed by magnetic resonance imaging (MRI) and immunohistochemistry. Function was evaluated by the Rogers and rotarod tests, and cell proliferation and cell-death were also determined. Brain repair markers were analyzed by confocal microscopy and confirmed by western blot. RESULTS: Compared to infarct group, function had significantly improved at 24 h and continued at 14 d after i.v. administration of either BM-MSC or AD-MSC. No reduction in infarct volume or any migration/implantation of cells into the damaged brain were observed. Nevertheless, cell death was reduced and cellular proliferation significantly increased in both treatment groups with respect to the infarct group. At 14 d after MSC administration vascular endothelial growth factor (VEGF), synaptophysin (SYP), oligodendrocyte (Olig-2) and neurofilament (NF) levels were significantly increased while those of glial fiibrillary acid protein (GFAP) were decreased. CONCLUSIONS: i.v. administration of allogenic MSC - whether BM-MSC or AD-MSC, in pMCAO infarct was associated with good functional recovery, and reductions in cell death as well as increases in cellular proliferation, neurogenesis, oligodendrogenesis, synaptogenesis and angiogenesis markers at 14 days post-infarct.


Assuntos
Tecido Adiposo/metabolismo , Biomarcadores/metabolismo , Medula Óssea/metabolismo , Encéfalo/metabolismo , Células-Tronco Mesenquimais/metabolismo , Acidente Vascular Cerebral/metabolismo , Administração Intravenosa/métodos , Animais , Morte Celular/fisiologia , Movimento Celular/fisiologia , Proliferação de Células/fisiologia , Modelos Animais de Doenças , Feminino , Proteína Glial Fibrilar Ácida/metabolismo , Infarto da Artéria Cerebral Média/metabolismo , Filamentos Intermediários/metabolismo , Imageamento por Ressonância Magnética/métodos , Transplante de Células-Tronco Mesenquimais/métodos , Neurogênese/fisiologia , Oligodendroglia/metabolismo , Ratos , Ratos Sprague-Dawley , Sinaptofisina/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo
19.
BMC Neurol ; 12: 95, 2012 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-22989378

RESUMO

BACKGROUND: The balance between T helper cells Th2- and Th1-related cytokines plays a key role in multiple sclerosis (MS). A shift from a Th1 towards a Th2 cytokine profile could have a beneficial effect on the clinical course of the disease. The objective of this study was to assess Th2/Th1 cytokine profile in relapsing-remitting MS (RRMS) patients receiving an immunosuppressive treatment with natalizumab (NAT), or an immunomodulatory treatment with glatiramer acetate (GA) after one year of treatment. METHODS: This was an observational cross-sectional study. All consecutive patients diagnosed with RRMS who had received GA or NAT for 12 months were included in the study. We determined serum levels of Th1 and Th2 cytokines (interleukin [IL]-1a, IL-1b, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12p70, IL-13, monocyte chemotactic protein [MCP]-1, tumor-necrosis factor [TNF]-α, interferon [IFN]-γ and granulocyte macrophage colony stimulating factor [GM-CSF]) by flow cytometry. Th2/Th1 bias was defined based on the ratio of IL-4, IL-5, IL-6 or IL-10 Th2 cytokines and proinflammatory INF-γ or TNF-α Th1 cytokines. RESULTS: Eleven patients under treatment with NAT and 12 patients treated with GA were evaluated. RRMS patients treated with NAT showed significantly higher levels of IL-6 (p < 0.05), MCP-1 (p < 0.01), and GM-CSF (p < 0.05) compared to GA patients after one year of treatment. A trend for increasing of IL-12p70, IL-1b, TNF- α and IFN- γ levels was also found in patients receiving NAT compared to GA patients. IL-4/IFN-γ, IFN-γ/TNF-α and IL-10/IFN-γ ratios as markers of Th2/Th1 ratio were significantly elevated in GA patients compared to those receiving NAT (p < 0.05). CONCLUSION: In conclusion, our findings suggest that GA promotes a superior Th2-biased anti-inflammatory response as compared with NAT in the systemic circulation of RRMS patients. Future studies with larger cohorts will determine whether this immune Th2 shift in GA patients is associated with a beneficial effect on disease outcome.


Assuntos
Anticorpos Monoclonais Humanizados/uso terapêutico , Citocinas/sangue , Citocinas/imunologia , Esclerose Múltipla/tratamento farmacológico , Esclerose Múltipla/imunologia , Peptídeos/uso terapêutico , Equilíbrio Th1-Th2/efeitos dos fármacos , Adjuvantes Imunológicos/uso terapêutico , Adulto , Acetato de Glatiramer , Humanos , Masculino , Esclerose Múltipla/sangue , Natalizumab , Prevenção Secundária , Resultado do Tratamento
20.
Neurol Res ; 34(7): 649-56, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22732142

RESUMO

Use of thrombolysis in acute ischaemic stroke may be limited by a narrow benefit/risk ratio. Pharmacological inhibition of the ischaemic cascade may constitute an effective and safer approach to stroke treatment. This study compared the effects of high doses of cytidine diphosphate-choline (CDP-choline; 1000 mg/kg) with recombinant tissue plasminogen activator (rt-PA; 5 mg/kg) in an experimental animal model of embolic stroke. Fifteen rats were embolized in the right internal carotid artery with an autologous clot and were divided into three groups: (1) infarct; (2) intravenous rt-PA 5 mg/kg 30 minutes post-embolization; and (3) CDP-choline 1000 mg/kg, intraperitoneal, three doses, 30 minutes, 24 hours, and 48 hours post-embolization. Functional evaluation scores were evaluated using Rogers test, lesion volume by haematoxylin and eosin staining, cell death with transferase-mediated dUTP nick-end labelling, and plasma levels of interleukin-6 (IL-6) and tumor necrosis factor-alpha with enzyme-linked immunosorbent assay. In this study, CDP-choline and rt-PA produced a significant reduction in brain damage considering infarct volume, cell death, and inflammatory cytokines (tumour necrosis factor-alpha and IL-6) compared with the infarct group. Additionally, CDP-choline significantly decreased infarct volume, cell death, and IL-6 levels with respect to the rt-PA group. From these results, we conclude that high-dose CDP-choline may be an effective treatment for acute ischaemic stroke even in absence of thrombolysis.


Assuntos
Citidina Difosfato Colina/administração & dosagem , Modelos Animais de Doenças , Acidente Vascular Cerebral/tratamento farmacológico , Terapia Trombolítica/métodos , Animais , Infusões Intravenosas , Masculino , Nootrópicos/administração & dosagem , Distribuição Aleatória , Ratos , Ratos Long-Evans , Acidente Vascular Cerebral/patologia , Ativador de Plasminogênio Tecidual/administração & dosagem , Resultado do Tratamento
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA