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Background: Current radiotherapy regimens for glioblastoma (GBM) have limited efficacy and fails to eradicate tumors. Regenerative medicine brings hope for repairing damaged tissue, opening opportunities for elevating the maximum acceptable radiation dose. In this study, we explored the effect of ultra-high dose fractionated radiation on tumor responses and brain injury in immunocompetent mice which can better mimic the tumor-host interactions observed in patients. We also evaluated the role of the hypoxia-inducible factor-1 alpha under radiation as potential target for combating radiation-induced brain injury. Methods: Naïve and Hif-1α+/- heterozygous mice received a fractionated daily dose of 20 Gy for three or five consecutive days. Magnetic resonance imaging (MRI) and histology were performed to assess brain injury post-radiation. The 2×105 human GBM1 luciferase-expressing cells were transplanted with tolerance induction protocol. Fractionated radiotherapy was performed during the exponential phase of tumor growth. Bioluminescence imaging, MRI, and immunohistochemistry staining were performed to evaluate tumor growth dynamics and radiotherapy responses. Additionally, animal lifespan was recorded. Results: Fractionated radiation of 5×20 Gy induced severe brain damage, starting 3 weeks after radiation. All animals from this group died within 12 weeks. In contrast, later onset and less severe brain injury were observed starting 12 weeks after radiation of 3×20 Gy. It resulted in complete GBM eradication and survival of all treated animals. Furthermore, Hif-1α+/- mice exhibited more severe vascular damage after fractionated radiation of 3×20 Gy. Conclusion: Ultra-high dose fractionated 3×20 Gy radiation has the potential to fully eradicate GBM cells at the cost of only mild brain injury. The Hif-1α gene is a promising target for ameliorating vascular impairment post-radiation, encouraging the implementation of neurorestorative strategies.
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Cerebral small vessel disease (CSVD) is increasingly being recognized as a leading contributor to cognitive impairment in the elderly. However, there is a lack of effective preventative or therapeutic options for CSVD. In this exploratory study, we investigated the interplay between neuroinflammation and CSVD pathogenesis as well as the cognitive performance, focusing on NLRP3 signaling as a new therapeutic target. Spontaneously hypertensive stroke-prone (SHRSP) rats served as a CSVD model. We found that SHRSP rats showed decline in learning and memory abilities using morris water maze test. Activated NLRP3 signaling and an increased expression of the downstream pro-inflammatory factors, including IL (interleukin)-6 and tumor necrosis factor α were determined. We also observed a remarkable increase in the production of pyroptosis executive protein gasdermin D, and elevated astrocytic and microglial activation. In addition, we identify several neuropathological hallmarks of CSVD, including blood-brain barrier breakdown, white matter damage, and endothelial dysfunction. These results were in correlation with the activation of NLRP3 inflammasome. Thus, our findings reveal that the NLRP3-mediated inflammatory pathway could play a central role in the pathogenesis of CSVD, presenting a novel target for potential CSVD treatment.
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Enfermedades de los Pequeños Vasos Cerebrales , Modelos Animales de Enfermedad , Inflamasomas , Proteína con Dominio Pirina 3 de la Familia NLR , Ratas Endogámicas SHR , Animales , Enfermedades de los Pequeños Vasos Cerebrales/metabolismo , Enfermedades de los Pequeños Vasos Cerebrales/patología , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Ratas , Inflamasomas/metabolismo , Masculino , Enfermedades Neuroinflamatorias/metabolismo , Microglía/metabolismo , Barrera Hematoencefálica/metabolismo , Barrera Hematoencefálica/patología , Transducción de Señal/fisiologíaRESUMEN
The neural cell adhesion molecule (NCAM) promotes neural development and regeneration. Whether NCAM mimetic peptides could synergize with bone marrow mesenchymal stem cells (BMSCs) in stroke treatment deserves investigation. We found that the NCAM mimetic peptide P2 promoted BMSC proliferation, migration, and neurotrophic factor expression, protected neurons from oxygen-glucose deprivation through ERK and PI3K/AKT activation and anti-apoptotic mechanisms in vitro. Following middle cerebral artery occlusion (MCAO) in rats, P2 alone or in combination with BMSCs inhibited neuronal apoptosis and induced the phosphorylation of ERK and AKT. P2 combined with BMSCs enhanced neurotrophic factor expression and BMSC proliferation in the ischemic boundary zone. Moreover, combined P2 and BMSC therapy induced translocation of nuclear factor erythroid 2-related factor, upregulated heme oxygenase-1 expression, reduced infarct volume, and increased functional recovery as compared to monotreatments. Treatment with LY294002 (PI3K inhibitor) and PD98059 (ERK inhibitor) decreased the neuroprotective effects of combined P2 and BMSC therapy in MCAO rats. Collectively, P2 is neuroprotective while P2 and BMSCs work synergistically to improve functional outcomes after ischemic stroke, which may be attributed to mechanisms involving enhanced BMSC proliferation and neurotrophic factor release, anti-apoptosis, and PI3K/AKT and ERK pathways activation.
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Trasplante de Células Madre Mesenquimatosas , Células Madre Mesenquimatosas , Moléculas de Adhesión de Célula Nerviosa , Péptidos , Recuperación de la Función , Accidente Cerebrovascular , Animales , Masculino , Ratas , Apoptosis/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Infarto de la Arteria Cerebral Media/terapia , Infarto de la Arteria Cerebral Media/metabolismo , Trasplante de Células Madre Mesenquimatosas/métodos , Células Madre Mesenquimatosas/metabolismo , Células Madre Mesenquimatosas/efectos de los fármacos , Moléculas de Adhesión de Célula Nerviosa/metabolismo , Péptidos/farmacología , Péptidos/uso terapéutico , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Ratas Sprague-Dawley , Recuperación de la Función/efectos de los fármacos , Recuperación de la Función/fisiología , Accidente Cerebrovascular/terapia , Accidente Cerebrovascular/metabolismoRESUMEN
Background: Conventional radiation therapy for glioblastoma (GBM) has limited efficacy. Regenerative medicine brings hope for repairing damaged tissue, opening opportunities for elevating the maximum acceptable radiation dose. In this study, we explored the effect of ultra-high dose fractionated radiation on brain injury and tumor responses in immunocompetent mice. We also evaluated the role of the HIF-1α under radiation. Methods: Naïve and hypoxia-inducible factor-1 alpha (HIF-1α)+/- heterozygous mice received a fractionated daily dose of 20 Gy for three or five consecutive days. Magnetic resonance imaging (MRI) and histology were performed to assess brain injury post-radiation. The 2×105 human GBM1 luciferase-expressing cells were transplanted with tolerance induction protocol. Fractionated radiotherapy was performed during the exponential phase of tumor growth. BLI, MRI, and immunohistochemistry staining were performed to evaluate tumor growth dynamics and radiotherapy responses. Additionally, animal lifespan was recorded. Results: Fractionated radiation of 5×20 Gy induced severe brain damage, starting 3 weeks after radiation. All animals from this group died within 12 weeks. In contrast, later onset and less severe brain injury were observed starting 12 weeks after radiation of 3×20 Gy. It resulted in complete GBM eradication and survival of all treated animals. Furthermore, HIF-1α+/- mice exhibited more obvious vascular damage 63 weeks after fractionated radiation of 3×20 Gy. Conclusion: Ultra-high dose fractionated 3×20 Gy radiation can eradicate the GBM cells at the cost of only mild brain injury. The HIF-1α gene is a promising target for ameliorating vascular impairment post-radiation, encouraging the implementation of neurorestorative strategies.
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The fluorophores in the second near-infrared (NIR-II) biological window (1000 - 1700 nm) show great application prospects in the fields of biology and optical communications. However, both excellent radiative transition and nonradiative transition cannot be achieved simultaneously for the majority of traditional fluorophores. Herein, tunable nanoparticles formulated with aggregation-induced emission (AIE) heater are developed rationally. The system can be implemented via the development of an ideal synergistic system that can not only produce photothermal from nonspecific triggers but also trigger carbon radical release. Once accumulating in tumors and subsequently being irradiated with 808 nm laser, the nanoparticles (NMB@NPs) encapsulated with NMDPA-MT-BBTD (NMB) are splitted due to the photothermal effect of NMB, leading to the decomposition of azo bonds in the nanoparticle matrix to generate carbon radical. Accompanied by second near-infrared (NIR-II) window emission from the NMB, fluorescence image-guided thermodynamic therapy (TDT) and photothermal therapy (PTT) which significantly inhibited the growth of oral cancer and negligible systemic toxicity is achieved synergistically. Taken together, this AIE luminogens-based synergistic photothermal-thermodynamic strategy brings a new insight into the design of superior versatile fluorescent NPs for precise biomedical applications and holds great promise to enhance the therapeutic efficacy of cancer therapy.
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Neoplasias de la Boca , Nanopartículas , Humanos , Fototerapia , Xenoinjertos , Nanopartículas/química , Colorantes Fluorescentes/química , Neoplasias de la Boca/terapiaRESUMEN
PURPOSE: Mannitol is a hyperosmolar agent for reducing intracranial pressure and inducing osmotic blood-brain barrier opening (OBBBO). There is a great clinical need for a non-invasive method to optimize the safety of mannitol dosing. The aim of this study was to develop a label-free Chemical Exchange Saturation Transfer (CEST)-based MRI approach for detecting intracranial accumulation of mannitol following OBBBO. METHODS: In vitro MRI was conducted to measure the CEST properties of D-mannitol of different concentrations and pH. In vivo MRI and MRS measurements were conducted on Sprague-Dawley rats using a Biospec 11.7T horizontal MRI scanner. Rats were catheterized at the internal carotid artery (ICA) and randomly grouped to receive either 1 mL or 3 mL D-mannitol. CEST MR images were acquired before and at 20 min after the infusion. RESULTS: In vitro MRI showed that mannitol has a strong, broad CEST contrast at around 0.8 ppm with a mM CEST MRI detectability. In vivo studies showed that CEST MRI could effectively detect mannitol in the brain. The low dose mannitol treatment led to OBBBO but no significant mannitol accumulation, whereas the high dose regimen resulted in both OBBBO and mannitol accumulation. The CEST MRI findings were consistent with 1H-MRS and Gd-enhanced MRI assessments. CONCLUSION: We demonstrated that CEST MRI can be used for non-invasive, label-free detection of mannitol accumulation in the brain following BBBO treatment. This method may be useful as a rapid imaging tool to optimize the dosing of mannitol-based OBBBO and improve its safety and efficacy.
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Cerebral small vessel disease (CSVD) represents a diverse cluster of cerebrovascular diseases primarily affecting small arteries, capillaries, arterioles and venules. The diagnosis of CSVD relies on the identification of small subcortical infarcts, lacunes, white matter hyperintensities, perivascular spaces, and microbleeds using neuroimaging. CSVD is observed in 25% of strokes worldwide and is the most common pathology of cognitive decline and dementia in the elderly. Still, due to the poor understanding of pathophysiology in CSVD, there is not an effective preventative or therapeutic approach for CSVD. The most widely accepted approach to CSVD treatment is to mitigate vascular risk factors and adopt a healthier lifestyle. Thus, a deeper understanding of pathogenesis may foster more specific therapies. Here, we review the underlying mechanisms of pathological characteristics in CSVD development, with a focus on endothelial dysfunction, blood-brain barrier impairment and white matter change. We also describe inflammation in CSVD, whose role in contributing to CSVD pathology is gaining interest. Finally, we update the current treatments and preventative measures of CSVD, as well as discuss potential targets and novel strategies for CSVD treatment.
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BACKGROUND: Multiple sclerosis (MS) is a neurodegenerative disease, wherein aberrant immune cells target myelin-ensheathed nerves. Conventional magnetic resonance imaging (MRI) can be performed to monitor damage to the central nervous system that results from previous inflammation; however, these imaging biomarkers are not necessarily indicative of active, progressive stages of the disease. The immune cells responsible for MS are first activated and sensitized to myelin in lymph nodes (LNs). Here, we present a new strategy for monitoring active disease activity in MS, chemical exchange saturation transfer (CEST) MRI of LNs. METHODS AND RESULTS: We studied the potential utility of conventional (T2-weighted) and CEST MRI to monitor changes in these LNs during disease progression in an experimental autoimmune encephalomyelitis (EAE) model. We found CEST signal changes corresponded temporally with disease activity. CEST signals at the 3.2 ppm frequency during the active stage of EAE correlated significantly with the cellular (flow cytometry) and metabolic (mass spectrometry imaging) composition of the LNs, as well as immune cell infiltration into brain and spinal cord tissue. Correlating primary metabolites as identified by matrix-assisted laser desorption/ionization (MALDI) imaging included alanine, lactate, leucine, malate, and phenylalanine. CONCLUSIONS: Taken together, we demonstrate the utility of CEST MRI signal changes in superficial cervical LNs as a complementary imaging biomarker for monitoring disease activity in MS. CEST MRI biomarkers corresponded to disease activity, correlated with immune activation (surface markers, antigen-stimulated proliferation), and correlated with LN metabolite levels.
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Encefalomielitis Autoinmune Experimental , Esclerosis Múltiple , Enfermedades Neurodegenerativas , Animales , Encefalomielitis Autoinmune Experimental/diagnóstico por imagen , Encefalomielitis Autoinmune Experimental/patología , Ganglios Linfáticos/diagnóstico por imagen , Ganglios Linfáticos/patología , Imagen por Resonancia Magnética/métodos , Ratones , Esclerosis Múltiple/diagnóstico por imagen , Espectrometría de Masa por Láser de Matriz Asistida de Ionización DesorciónRESUMEN
The blood-brain barrier (BBB) is the main obstacle to the effective delivery of therapeutic agents to the brain, compromising treatment efficacy for a variety of neurological disorders. Intra-arterial (IA) injection of hyperosmotic mannitol has been used to permeabilize the BBB and improve parenchymal entry of therapeutic agents following IA delivery in preclinical and clinical studies. However, the reproducibility of IA BBB manipulation is low and therapeutic outcomes are variable. We demonstrated that this variability could be highly reduced or eliminated when the procedure of osmotic BBB opening is performed under the guidance of interventional MRI. Studies have reported the utility and applicability of this technique in several species. Here we describe a protocol to open the BBB by IA injection of hyperosmotic mannitol under the guidance of MRI in mice. The procedures (from preoperative preparation to postoperative care) can be completed within ~1.5 h, and the skill level required is on par with the induction of middle cerebral artery occlusion in small animals. This MRI-guided BBB opening technique in mice can be utilized to study the biology of the BBB and improve the delivery of various therapeutic agents to the brain.
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Barrera Hematoencefálica , Inyecciones Intraarteriales , Imagen por Resonancia Magnética , Manitol , Animales , Barrera Hematoencefálica/diagnóstico por imagen , Barrera Hematoencefálica/efectos de los fármacos , Permeabilidad Capilar/efectos de los fármacos , Masculino , Manitol/administración & dosificación , Manitol/farmacología , Ratones , Ratones SCID , Presión OsmóticaRESUMEN
Bone marrow mesenchymal stem cells (BMSCs) have been shown to promote stroke recovery, however, the underlying mechanisms are not well understood. In this study naïve rats were intravenously injected with syngeneic BMSCs to screen for potential differences in brain metabolite spectrum versus vehicle-treated controls by capillary electrophoresis-mass spectrometry. A total of 65 metabolites were significantly changed after BMSC treatment. Among them, 5-oxoproline, an intermediate in the biosynthesis of the endogenous glutathione (GSH), was increased. To confirm the obtained results and investigate the metabolic pathways, BMSCs were injected into rats 24 h after middle cerebral artery occlusion (MCAO). Rats receiving vehicle solution and sham-operated animals served as controls. High performance liquid chromatography, reverse transcription-quantitative polymerase chain reaction, and Western blotting revealed that intravenous BMSC application increased the levels of 5-oxoproline and GSH in MCAO rats, as well as the expression of key enzymes involved in GSH synthesis including, gamma-glutamylcyclotransferase and gamma-glutamylcysteine ligase. Subsequent clinical investigation confirmed that acute ischemic stroke patients had higher plasma 5-oxoproline and GSH levels than age- and sex-matched non-stroke controls. The optimal cutoff value for 5-oxoproline diagnosing acute ischemic stroke (≤ 7d) was 3.127 µg/mL (sensitivity, 63.4 %; specificity, 81.2 %) determined by receiver characteristic operator curve. The area under the curve was 0.782 (95 % confidence interval: 0.718-0.845). Our findings indicate that BMSCs play a protective role in ischemic stroke through upregulation of GSH and 5-oxoproline is a potential biomarker for acute ischemic stroke. Ischemic stroke causes oxidative stress and induction of endogenous, glutathione-dependent anti-oxidative mechanisms. 5-oxoproline, an important metabolite in glutathione biosynthesis, could serve as a biomarker of acute ischemic stroke. Moreover, intravenous bone marrow mesenchymal stem cell (BMSC) treatment after experimental stroke upregulates the expression of key enzymes involved in glutathione synthesis, which results in better antioxidative defense and improved stroke outcome.
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Accidente Cerebrovascular Isquémico , Células Madre Mesenquimatosas , Accidente Cerebrovascular , Animales , Células de la Médula Ósea/metabolismo , Glutatión/metabolismo , Glutatión/farmacología , Glutatión/uso terapéutico , Humanos , Infarto de la Arteria Cerebral Media/metabolismo , Células Madre Mesenquimatosas/metabolismo , Ácido Pirrolidona Carboxílico/metabolismo , Ácido Pirrolidona Carboxílico/farmacología , Ácido Pirrolidona Carboxílico/uso terapéutico , Ratas , Accidente Cerebrovascular/metabolismo , Accidente Cerebrovascular/terapia , Regulación hacia ArribaRESUMEN
Rapidly ageing populations are beset by tissue wear and damage. Stem cell-based regenerative medicine is considered a solution. Years of research point to two important aspects: (1) the use of cellular imaging to achieve sufficient precision of therapeutic intervention, and the fact that (2) many therapeutic actions are executed through extracellular vesicles (EV), released by stem cells. Therefore, there is an urgent need to interrogate cellular labels in the context of EV release. We studied clinically applicable cellular labels: superparamagnetic iron oxide nanoparticles (SPION), and radionuclide detectable by two main imaging modalities: MRI and PET. We have demonstrated effective stem cell labeling using both labels. Then, we obtained EVs from cell cultures and tested for the presence of cellular labels. We did not find either magnetic or radioactive labels in EVs. Therefore, we report that stem cells do not lose labels in released EVs, which indicates the reliability of stem cell magnetic and radioactive labeling, and that there is no interference of labels with EV content. In conclusion, we observed that direct cellular labeling seems to be an attractive approach to monitoring stem cell delivery, and that, importantly, labels neither locate in EVs nor affect their basic properties.
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The blood-brain barrier (BBB) tightly controls entry of molecules and cells into the brain, restricting the delivery of therapeutics. Blood-brain barrier opening (BBBO) utilizes reversible disruption of cell-cell junctions between brain microvascular endothelial cells to enable transient entry into the brain. Here, we demonstrate that melittin, a membrane active peptide present in bee venom, supports transient BBBO. From endothelial and neuronal viability studies, we first identify the accessible concentration range for BBBO. We then use a tissue-engineered model of the human BBB to optimize dosing and elucidate the mechanism of opening. Melittin and other membrane active variants transiently increase paracellular permeability via disruption of cell-cell junctions that result in transient focal leaks. To validate the results from the tissue-engineered model, we then demonstrate that transient BBBO can be reproduced in a mouse model. We identify a minimum clinically effective intra-arterial dose of 3 µM min melittin, which is reversible within one day and neurologically safe. Melittin-induced BBBO represents a novel technology for delivery of therapeutics into the brain.
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Barrera Hematoencefálica , Meliteno , Animales , Transporte Biológico , Encéfalo , Células Endoteliales , RatonesRESUMEN
Rationale: Endovascular intervention plays an important role in the treatment of various diseases, in which MRI-guidance can potentially improve precision. However, the clinical applications of currently available contrast media, including Gadolinium-based contrast agents and superparamagnetic iron oxide particles (SPIO), are hindered by safety concerns. In the present study, we sought to develop D2O as a novel contrast agent for guiding endovascular neurointervention. Methods: Animal studies were approved by institutional ACUC and conducted using an 11.7 T Bruker Biospec system and a 3T Siemens Trio clinical scanner for rodent and canine imaging, respectively. The locally selective blood brain barrier opening (BBBO) in rat brains was obtained by intraarterial (IA) injection of mannitol. The dynamic T2w* EPI MRI sequence was used to study the trans-catheter perfusion territory by IA administered SPIO before mannitol administration, whereas a dynamic T1w FLASH sequence was used to acquire Gd contrast-enhanced MRI for assessing BBBO after injection of mannitol. The contrast generated by D2O assessed by either EPI or FLASH methods was compared with the corresponding results assessed by SPIO or Gd. The utility of D2O MRI was also demonstrated to guide drug delivery to glioma in a mouse model. Finally, the clinical utility of D2O-MRI was demonstrated in a canine model. Results: Our study has shown that the contrast generated by D2O can be used to precisely delineate trans-catheter perfusion territory in both small and large animals. The perfusion territories determined by D2O-MRI show moderate correlation with those by SPIO-MRI (Spearman coefficient r = 0.5234, P < 0.001). Moreover, our results show that the perfusion territory determined by D2O-MRI can successfully predict the areas with BBBO after mannitol treatment similar to that assessed by Gd-MRI (Spearman coefficient r = 0.6923, P < 0.001). Using D2O-MRI as imaging guidance, the optimal infusion rate in the mouse brain was determined to be 150 µL/min to maximize the delivery efficacy to the tumor without serious off-target delivery to the brain parenchyma. The enhanced drug delivery of antibodies to the brain tumor was confirmed by fluorescence imaging. Conclusion: Our study demonstrated that D2O can be used as a negative MRI contrast medium to guide endovascular neurointervention. The established D2O -MRI method is safe and quantitative, without the concern of contrast accumulation. These qualities make it an attempting approach for a variety of endovascular procedures.
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Medios de Contraste , Óxido de Deuterio , Procedimientos Endovasculares , Imagen por Resonancia Magnética/métodos , Neuroimagen/métodos , Cirugía Asistida por Computador/métodos , Animales , Barrera Hematoencefálica/efectos de los fármacos , Neoplasias Encefálicas/diagnóstico por imagen , Arteria Carótida Interna , Cateterismo , Sistemas de Computación , Medios de Contraste/farmacocinética , Óxido de Deuterio/farmacocinética , Perros , Sistemas de Liberación de Medicamentos , Femenino , Compuestos Férricos , Glioma/diagnóstico por imagen , Infusiones Intraarteriales , Inyecciones Intraarteriales , Masculino , Manitol/farmacología , Ratones , Ratones Endogámicos C57BL , Fantasmas de Imagen , Ratas , Ratas Sprague-Dawley , Distribución TisularRESUMEN
Transplanted glial-restricted progenitor (GRP) cells have potential to focally replace defunct astrocytes and produce remyelinating oligodendrocytes to avert neuronal death and dysfunction. However, most central nervous system cell therapeutic paradigms are hampered by high initial cell death and a host anti-graft immune response. We show here that composite hyaluronic acid-based hydrogels of tunable mechanical strengths can significantly improve transplanted GRP survival and differentiation. Allogeneic GRPs expressing green fluorescent protein and firefly luciferase were scaffolded in optimized hydrogel formulations and transplanted intracerebrally into immunocompetent BALB/c mice followed by serial in vivo bioluminescent imaging and chemical exchange saturation transfer magnetic resonance imaging (CEST MRI). We demonstrate that gelatin-sensitive CEST MRI can be exploited to monitor hydrogel scaffold degradation in vivo for â¼5 weeks post transplantation without necessitating exogenous labeling. Hydrogel scaffolding of GRPs resulted in a 4.5-fold increase in transplanted cell survival at day 32 post transplantation compared to naked cells. Histological analysis showed significant enhancement of cell proliferation as well as Olig2+ and GFAP+ cell differentiation for scaffolded cells compared to naked cells, with reduced host immunoreactivity. Hence, hydrogel scaffolding of transplanted GRPs in conjunction with serial in vivo imaging of cell survival and hydrogel degradation has potential for further advances in glial cell therapy.
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Supervivencia Celular/fisiología , Hidrogeles/química , Neuroglía , Imagen Óptica/métodos , Células Madre , Animales , Diferenciación Celular/fisiología , Rastreo Celular , Ácido Hialurónico/química , Imagen por Resonancia Magnética , Masculino , Ratones , Ratones Endogámicos BALB C , Neuroglía/citología , Neuroglía/fisiología , Neuroglía/trasplante , Trasplante de Células Madre , Células Madre/citología , Células Madre/fisiologíaRESUMEN
BACKGROUND: Cell transplantation-based treatments for neurological disease are promising, yet graft rejection remains a major barrier to successful regenerative therapies. Our group and others have shown that long-lasting tolerance of transplanted stem cells can be achieved in the brain with systemic application of monoclonal antibodies blocking co-stimulation signaling. However, it is unknown if subsequent injury and the blood-brain barrier breach could expose the transplanted cells to systemic immune system spurring fulminant rejection and fatal encephalitis. Therefore, we investigated whether delayed traumatic brain injury (TBI) could trigger graft rejection. METHODS: Glial-restricted precursor cells (GRPs) were intracerebroventricularly transplanted in immunocompetent neonatal mice and co-stimulation blockade (CoB) was applied 0, 2, 4, and 6 days post-grafting. Bioluminescence imaging (BLI) was performed to monitor the grafted cell survival. Mice were subjected to TBI 12 weeks post-transplantation. MRI and open-field test were performed to assess the brain damage and behavioral change, respectively. The animals were decapitated at week 16 post-transplantation, and the brains were harvested. The survival and distribution of grafted cells were verified from brain sections. Hematoxylin and eosin staining (HE) was performed to observe TBI-induced brain legion, and neuroinflammation was evaluated immunohistochemically. RESULTS: BLI showed that grafted GRPs were rejected within 4 weeks after transplantation without CoB, while CoB administration resulted in long-term survival of allografts. BLI signal had a steep rise following TBI and subsequently declined but remained higher than the preinjury level. Open-field test showed TBI-induced anxiety for all animals but neither CoB nor GRP transplantation intensified the symptom. HE and MRI demonstrated a reduction in TBI-induced lesion volume in GRP-transplanted mice compared with non-transplanted mice. Brain sections further validated the survival of grafted GRPs and showed more GRPs surrounding the injured tissue. Furthermore, the brains of post-TBI shiverer mice had increased activation of microglia and astrocytes compared to post-TBI wildtype mice, but infiltration of CD45+ leukocytes remained low. CONCLUSIONS: CoB induces sustained immunological tolerance towards allografted cerebral GRPs which is not disrupted following TBI, and unexpectedly TBI may enhance GRPs engraftment and contribute to post-injury brain tissue repair.
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Lesiones Traumáticas del Encéfalo , Rechazo de Injerto/inmunología , Tolerancia Inmunológica/inmunología , Células-Madre Neurales/trasplante , Trasplante de Células Madre/métodos , Aloinjertos , Animales , Anticuerpos Monoclonales/farmacología , Antígeno B7-1/antagonistas & inhibidores , Antígeno B7-2/antagonistas & inhibidores , Antígenos CD28/antagonistas & inhibidores , Antígenos CD40/antagonistas & inhibidores , Ratones , Ratones Endogámicos C57BL , Neuroglía/trasplanteRESUMEN
Unraveling the pathology of stroke is a prerequisite for designing therapeutic strategies. It was reported that myelin injury exceeded axonal loss in the peri-infarct region of rodent white matter stroke. An in-depth investigation of the post-stroke white matter damage in higher-order species might innovate stroke intervention. In this study, adult male cynomolgus monkeys received surgical middle cerebral artery occlusion (MCAO), and serial magnetic resonance scans to non-invasively assess brain damage. Spontaneous movements were recorded to evaluate post-stroke behavior. The axon and myelin loss, as well as immune cell infiltration were examined using immunohistochemistry. Magnetic resonance imaging revealed cerebral infarcts and white matter injury after MCAO in monkeys, which were confirmed by neurological deficits. Immunostaining of white matter fibers showed substantial demyelination whilst retention of axons in the infarcts 8 days post MCAO, while a progressive loss of myelin and axons was observed after one month. Gliosis, microglia activation, and leukocyte infiltration were identified in the lesions. These results demonstrate that demyelination predates axonal injury in non-human primate ischemic stroke, which provides a time window for stroke intervention focusing on prevention of progressive axonal loss through myelin regeneration.
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Axones/patología , Isquemia Encefálica/patología , Enfermedades Desmielinizantes/patología , Accidente Cerebrovascular Isquémico/patología , Sustancia Blanca/patología , Animales , Axones/química , Axones/inmunología , Isquemia Encefálica/inmunología , Enfermedades Desmielinizantes/inmunología , Gliosis/inmunología , Gliosis/patología , Accidente Cerebrovascular Isquémico/inmunología , Macaca fascicularis , Masculino , Sustancia Blanca/química , Sustancia Blanca/inmunologíaRESUMEN
Extracellular vesicles (EVs) are natural and diverse lipid bilayer-enclosed particles originating from various cellular components and containing an abundance of cargoes. Due to their unique properties, EVs have gained considerable interest as therapeutic agents for a variety of diseases, including central nervous system (CNS) disorders. Their therapeutic value depends on cell origin but can be further enhanced by enrichment of cargo when used as drug carriers. Therefore, there has been significant effort directed toward introducing them to clinical practice. However, it is essential to avoid the failures we have seen with whole-cell therapy, in particular for the treatment of the CNS. Successful launching of clinical studies is contingent upon the understanding of the biodistribution of EVs, including their uptake and clearance from organs and specific homing into the region of interest. A multitude of noninvasive imaging methods has been explored in vitro to investigate the spatio-temporal dynamics of EVs administered in vivo. However, only a few studies have been performed to track the delivery of EVs, especially delivery to the brain, which is the most therapeutically challenging organ. We focus here on the use of advanced imaging techniques as an essential tool to facilitate the acceleration of clinical translation of EV-based therapeutics, especially in the CNS arena. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Neurological Disease Diagnostic Tools > in vivo Nanodiagnostics and Imaging.
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Enfermedades del Sistema Nervioso Central , Sistemas de Liberación de Medicamentos , Vesículas Extracelulares , Nanomedicina , Enfermedades del Sistema Nervioso Central/tratamiento farmacológico , Vesículas Extracelulares/metabolismo , Humanos , Distribución TisularRESUMEN
Photoacoustic (PA) technology can transform light energy into acoustic wave, which can be used for either imaging or therapy that depends on the power density of pulsed laser. Here, we report photosensitizer-free polymeric nanocapsules loaded with nitric oxide (NO) donors, namely NO-NCPs, formulated from NIR light-absorbable amphiphilic polymers and a NO-releasing donor, DETA NONOate. Controlled NO release and nanocapsule dissociation are achieved in acidic lysosomes of cancer cells. More importantly, upon pulsed laser irradiation, the PA cavitation can excite water to generate significant reactive oxygen species (ROS) such as superoxide radical (O2.- ), which further spontaneously reacts with the in situ released NO to burst highly cytotoxic peroxynitrite (ONOO- ) in cancer cells. The resultant ONOO- generation greatly promotes mitochondrial damage and DNA fragmentation to initiate programmed cancer cell death. Apart from PA imaging, PA cavitation can intrinsically amplify reactive species via photosensitization-free materials for promising disease theranostics.
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Rayos Infrarrojos , Nanocápsulas/química , Ácido Peroxinitroso/química , Polímeros/química , Especies Reactivas de Oxígeno/metabolismo , Animales , Antineoplásicos/química , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Clorofilidas , Daño del ADN/efectos de los fármacos , Lisosomas/efectos de los fármacos , Lisosomas/metabolismo , Ratones , Neoplasias/tratamiento farmacológico , Neoplasias/patología , Óxido Nítrico/metabolismo , Donantes de Óxido Nítrico/química , Ácido Peroxinitroso/uso terapéutico , Ácido Peroxinitroso/toxicidad , Técnicas Fotoacústicas , Porfirinas/farmacología , Porfirinas/uso terapéutico , Superóxidos/metabolismo , Nanomedicina Teranóstica , Trasplante HomólogoRESUMEN
Currently, human glioma tumors are mostly modeled in immunodeficient recipients; however, lack of interactions with adaptive immune system is a serious flaw, particularly in the era when immunotherapies dominate treatment strategies. Our group was the first to successfully establish the orthotopic transplantation of human glioblastoma (GBM) in immunocompetent mice by inducing immunological tolerance using a short-term, systemic costimulation blockade strategy (CTLA-4-Ig and MR1). In this study, we further validated the feasibility of this method by modeling pediatric diffuse intrinsic pontine glioma (DIPG) and two types of adult GBM (GBM1, GBM551), in mice with intact immune systems and immunodeficient mice. We found that all three glioma models were successfully established, with distinct difference in tumor growth patterns and morphologies, after orthotopic xenotransplantation in tolerance-induced immunocompetent mice. Long-lasting tolerance that is maintained for up to nearly 200 d in GBM551 confirmed the robustness of this model. Moreover, we found that tumors in immunocompetent mice displayed features more similar to the clinical pathophysiology found in glioma patients, characterized by inflammatory infiltration and strong neovascularization, as compared with tumors in immunodeficient mice. In summary, we have validated the robustness of the costimulatory blockade strategy for tumor modeling and successfully established three human glioma models including the pediatric DIPG whose preclinical study is particularly thwarted by the lack of proper animal models.
Asunto(s)
Neoplasias del Tronco Encefálico , Glioblastoma , Glioma , Adulto , Animales , Niño , Humanos , Ratones , Neovascularización PatológicaRESUMEN
Radiation therapy is a standard and effective non-surgical treatment for primary brain tumors and metastases. However, this strategy inevitably results in damage of normal brain tissue, causing severe complications, especially the late-delayed cognitive impairment. Due to the multifactorial and complex pathological effects of radiation, there is a lack of effective preventative and restorative treatments for the irradiated brain. Stem-cell therapy has held considerable promise for decades in the treatment of central nervous system (CNS) disorders because of its unique capacity for tissue repair and functional integrity. Currently, there is growing interest in using stem cells as a novel option to attenuate the adverse effects of irradiation. In the present review, we discuss recent studies evaluating stem-cell therapies for the irradiated brain and their therapeutic effects on ameliorating radiation-related brain injury as well as their potential challenges in clinical applications. We discuss these works in context of the pathogenesis of radiation-induced injury to CNS tissue in an attempt to elucidate the potential mechanisms of engrafted stem cells to reverse radiation-induced degenerative processes.