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Blood components released by erythrolysis play an important role in secondary brain injury and posthemorrhagic hydrocephalus (PHH) after intraventricular hemorrhage (IVH). The current study examined the impact of N-acetylheparin (NAH), a complement inhibitor, on early erythrolysis, PHH and iron accumulation in aged rats following IVH. This study, on 18-months-old male Fischer 344 rats, was in 3 parts. First, rats had an intracerebroventricular injection of autologous blood (IVH) mixed with NAH or saline, or saline alone. After MRI at four hours, Western blot and immunohistochemistry examined complement activation and electron microscopy choroid plexus and periventricular damage. Second, rats had an IVH with NAH or vehicle, or saline. Rats underwent serial MRI at 4 h and 1 day to assess ventricular volume and erythrolysis. Immunohistochemistry and H&E staining examined secondary brain injury. Third, rats had an IVH with NAH or vehicle. Serial MRIs on day 1 and 28 assessed ventricular volume and iron accumulation. H&E staining and immunofluorescence evaluated choroid plexus phagocytes. Complement activation was found 4 h after IVH, and co-injection of NAH inhibited that activation. NAH administration attenuated erythrolysis, reduced ventricular volume, alleviated periventricular and choroid plexus injury at 4 h and 1 day after IVH. NAH decreased iron accumulation, the number of choroid plexus phagocytes, and attenuated hydrocephalus at 28 days after IVH. Inhibiting complement can reduce early erythrolysis, attenuates hydrocephalus and iron accumulation after IVH in aged animals.
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BACKGROUND: Intraventricular hemorrhage (IVH) and associated hydrocephalus are significant complications of intracerebral and subarachnoid hemorrhage. Despite proximity to IVH, the immune cell response at the choroid plexus (ChP) has been relatively understudied. This study employs CX3CR-1GFP mice, which marks multiple immune cell populations, and immunohistochemistry to outline that response. METHODS: This study had four parts all examining male adult CX3CR-1GFP mice. Part 1 examined naïve mice. In part 2, mice received an injection 30 µl of autologous blood into right ventricle and were euthanized at 24 h. In part 3, mice underwent intraventricular injection of saline, iron or peroxiredoxin 2 (Prx-2) and were euthanized at 24 h. In part 4, mice received intraventricular iron injection and were treated with either control or clodronate liposomes and were euthanized at 24 h. All mice underwent magnetic resonance imaging to quantify ventricular volume. The ChP immune cell response was examined by combining analysis of GFP(+) immune cells and immunofluorescence staining. RESULTS: IVH and intraventricular iron or Prx-2 injection in CX3CR-1GFP mice all induced ventriculomegaly and activation of ChP immune cells. There were very marked increases in the numbers of ChP epiplexus macrophages, T lymphocytes and neutrophils. Co-injection of clodronate liposomes with iron reduced the ventriculomegaly which was associated with fewer epiplexus and stromal macrophages but not reduced T lymphocytes and neutrophils. CONCLUSION: There is a marked immune cell response at the ChP in IVH involving epiplexus cells, T lymphocytes and neutrophils. The blood components iron and Prx-2 may play a role in eliciting that response. Reduction of ChP macrophages with clodronate liposomes reduced iron-induced ventriculomegaly suggesting that ChP macrophages may be a promising therapeutic target for managing IVH-induced hydrocephalus.
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Plexo Corióideo , Modelos Animais de Doenças , Hidrocefalia , Animais , Plexo Corióideo/imunologia , Hidrocefalia/etiologia , Hidrocefalia/imunologia , Masculino , Camundongos , Camundongos Transgênicos , Hemorragia Cerebral Intraventricular/imunologia , Macrófagos/imunologia , Ferro/metabolismoRESUMO
OBJECTIVE: The pathophysiology of posthemorrhagic hydrocephalus (PHH) is not well understood, but recent data suggest blood components play a significant role. This study aimed to understand the timing of membrane attack complex (MAC) activation after intraventricular hemorrhage (IVH) and the effect of MAC inhibition on PHH development. METHODS: This study was composed of four parts. First, 24 young adult male rats underwent stereotactic intraventricular injection of autologous blood or saline and MRI on day 1, 3, or 7 after hemorrhage. Second, 18 rats underwent intraventricular injection of saline, autologous blood with aurin tricarboxylic acid (ATA) in vehicle, or autologous blood with vehicle and underwent serial MRI studies on days 1 and 3 after hemorrhage. Third, 12 rats underwent intraventricular injections as above and MRI 2 hours after hemorrhage. Finally, 24 rats underwent the intraventricular injections as above, as well as serial MRI studies on days 1, 7, 14, and 28 after hemorrhage. The MR images were used to calculate ventricular volume and iron deposition. Open field testing was performed to assess functional outcomes. Outcomes on day 28 were reported as a ratio to the animal's baseline values and normalized via log-transformation. Statistical analysis included the Shapiro-Wilk tests for normality and t-tests and 1-way analysis of variance for 2 and 3 groups of continuous variables, respectively. RESULTS: MAC was found within the hematoma 1 day after hemorrhage and persisted until day 7. Administration of ATA resulted in similar intraventricular hematoma volumes compared to vehicle 2 hours after hemorrhage. At 1 and 3 days after hemorrhage, ATA administration resulted in significantly smaller ventricular volumes and less hemolysis within the hematoma than in the vehicle animals. Administration of ATA also resulted in significantly smaller ventriculomegaly and less iron deposition in the periventricular area than in the vehicle rats 28 days after hemorrhage. Functionally, ATA rats were significantly faster, traveled longer distances, and spent less time resting than vehicle rats at 28 days. CONCLUSIONS: MAC was activated early and persisted within the hematoma until day 7 after IVH. MAC inhibition attenuated hemolysis in the clot and ventriculomegaly acutely after IVH. One month after hemorrhage, MAC inhibition attenuated ventriculomegaly and iron accumulation and improved functional outcomes.
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Cerebral cavernous malformation type-3 (CCM3) is a type of brain vascular malformation caused by mutations in programmed cell death protein-10 (PDCD10). It is characterized by early life occurrence of hemorrhagic stroke and profound blood-brain barrier defects. The pathogenic mechanisms responsible for microvascular hyperpermeability and lesion progression in CCM3 are still largely unknown. The current study examined brain endothelial barrier structural defects formed in the absence of CCM3 in vivo and in vitro that may lead to CCM3 lesion leakage. We found significant upregulation of a 20 kDa isoform of connexin 43 (GJA1-20 k) in brain endothelial cells (BEC) in both non-leaky and leaky lesions, as well as in an in vitro CCM3 knockdown model (CCM3KD-BEC). Morphological, biochemical, FRET, and FRAP analyses of CCM3KD-BEC found GJA1-20 k regulates full-length GJA1 biogenesis, prompting uncontrolled gap junction growth. Furthermore, by binding to a tight junction scaffolding protein, ZO-1, GJA1-20 k interferes with Cx43/ZO-1 interactions and gap junction/tight junction crosstalk, promoting ZO-1 dissociation from tight junction complexes and diminishing claudin-5/ZO-1 interaction. As a consequence, the tight junction complex is destabilized, allowing "replacement" of tight junctions with gap junctions leading to increased brain endothelial barrier permeability. Modifying cellular levels of GJA1-20 k rescued brain endothelial barrier integrity re-establishing the spatial organization of gap and tight junctional complexes. This study highlights generation of potential defects at the CCM3-affected brain endothelial barrier which may underlie prolonged vascular leakiness.
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Hemangioma Cavernoso do Sistema Nervoso Central , Humanos , Barreira Hematoencefálica , Encéfalo , Conexina 43 , Células EndoteliaisRESUMO
Intracerebral hemorrhage is primarily a disease of the elderly and it is frequently accompanied by intraventricular hemorrhage (IVH) which can lead to posthemorrhagic hydrocephalus and poor prognosis. Red blood cell iron has been implicated in brain injury after cerebral hemorrhage. The current study examined using T2* magnetic resonance imaging (MRI) to detect periventricular iron deposition after IVH and investigated the effects of minocycline on hydrocephalus in an aged rat IVH model. It had three parts. In part 1, male aged rats received a 200 µl injection of saline or autologous blood into the lateral ventricle and were euthanized at day 14. In parts 2 and 3, aged IVH rats were treated with vehicle or minocycline and euthanized at day 7 or 14. Rats underwent MRI to quantify hydrocephalus and iron deposition followed by brain histology and immunohistochemistry. Periventricular iron overload was found after IVH using T2* MRI and confirmed by histology. IVH also caused ventricular wall damage and increased the number of CD68(+) choroid plexus epiplexus cells. Minocycline administration reduced iron deposition and ventricular volume at days 7 and 14 after IVH, as well as ventricle wall damage and epiplexus cell activation. In summary, IVH-induced hydrocephalus is associated with periventricular iron deposition, ependymal damage and choroid plexus epiplexus cell activation in aged rats. Minocycline attenuated those effects and might be a potential treatment for posthemorrhagic hydrocephalus in the elderly.
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Hidrocefalia , Minociclina , Humanos , Ratos , Masculino , Animais , Idoso , Minociclina/farmacologia , Minociclina/uso terapêutico , Ratos Sprague-Dawley , Hemorragia Cerebral/complicações , Hemorragia Cerebral/diagnóstico por imagem , Hemorragia Cerebral/tratamento farmacológico , Ferro , Hidrocefalia/diagnóstico por imagem , Hidrocefalia/tratamento farmacológico , Hidrocefalia/etiologiaRESUMO
Both monocyte-derived macrophages (MDMs) and brain resident microglia participate in hematoma resolution after intracerebral hemorrhage (ICH). Here, we utilized a transgenic mouse line with enhanced green fluorescent protein (EGFP) labeled microglia (Tmem119-EGFP mice) combined with a F4/80 immunohistochemistry (a pan-macrophage marker) to visualize changes in MDMs and microglia after ICH. A murine model of ICH was used in which autologous blood was stereotactically injected into the right basal ganglia. The autologous blood was co-injected with CD47 blocking antibodies to enhance phagocytosis or clodronate liposomes for phagocyte depletion. In addition, Tmem119-EGFP mice were injected with the blood components peroxiredoxin 2 (Prx2) or thrombin. MDMs entered the brain and formed a peri-hematoma cell layer by day 3 after ICH and giant phagocytes engulfed red blood cells were found. CD47 blocking antibody increased the number of MDMs around and inside the hematoma and extended MDM phagocytic activity to day 7. Both MDMs and microglia could be diminished by clodronate liposomes. Intracerebral injection of Prx2 but not thrombin attracted MDMs into brain parenchyma. In conclusion, MDMs play an important role in phagocytosis after ICH which can be enhanced by CD47 blocking antibody, suggesting the modulation of MDMs after ICH could be a future therapeutic target.
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Antígeno CD47 , Microglia , Camundongos , Animais , Microglia/metabolismo , Antígeno CD47/metabolismo , Antígeno CD47/uso terapêutico , Ácido Clodrônico/farmacologia , Ácido Clodrônico/metabolismo , Ácido Clodrônico/uso terapêutico , Lipossomos/metabolismo , Macrófagos/metabolismo , Hemorragia Cerebral/metabolismo , Camundongos Transgênicos , Hematoma/metabolismoRESUMO
Evidence indicates that erythrocyte-derived iron and inflammation both play a role in intraventricular hemorrhage-induced brain injury including hydrocephalus. Many immune-associated cells, primarily stromal macrophages, reside at the choroid plexus where they are involved in inflammatory responses and antigen presentation. However, whether intraventricular iron impacts those stromal cells is unknown. The aim of this study was to evaluate the relationship between choroid plexus stromal macrophages and iron-induced hydrocephalus in rats and the impact of minocycline and clodronate liposomes on those changes. Aged (18-month-old) and young (3-month-old) male Fischer 344 rats were used to study choroid plexus stromal macrophages. Rats underwent intraventricular iron injection to induce hydrocephalus and treated with either minocycline, a microglia/macrophage inhibitor, or clodronate liposomes, a macrophage depleting agent. Ventricular volume was measured using magnetic resonance imaging, and stromal macrophages were quantified by immunofluorescence staining. We found that stromal macrophages accounted for about 10% of the total choroid plexus cells with more in aged rats. In both aged and young rats, intraventricular iron injection resulted in hydrocephalus and increased stromal macrophage number. Minocycline or clodronate liposomes ameliorated iron-induced hydrocephalus and the increase in stromal macrophages. In conclusion, stromal macrophages account for ~10% of all choroid plexus cells, with more in aged rats. Treatments targeting macrophages (minocycline and clodronate liposomes) are associated with reduced iron-induced hydrocephalus.
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Hidrocefalia , Ferro , Ratos , Masculino , Animais , Minociclina/farmacologia , Ratos Sprague-Dawley , Plexo Corióideo/patologia , Ácido Clodrônico/farmacologia , Lipossomos , Hidrocefalia/induzido quimicamente , Hidrocefalia/patologia , Ratos Endogâmicos F344 , MacrófagosRESUMO
Cerebral cavernous malformation (CCM) is a cerebromicrovascular disease that affects up to 0.5% of the population. Vessel dilation, decreased endothelial cell-cell contact, and loss of junctional complexes lead to loss of brain endothelial barrier integrity and hemorrhagic lesion formation. Leakage of hemorrhagic lesions results in patient symptoms and complications, including seizures, epilepsy, focal headaches, and hemorrhagic stroke. CCMs are classified as sporadic (sCCM) or familial (fCCM), associated with loss-of-function mutations in KRIT1/CCM1, CCM2, and PDCD10/CCM3. Identifying the CCM proteins has thrust the field forward by (1) revealing cellular processes and signaling pathways underlying fCCM pathogenesis, and (2) facilitating the development of animal models to study CCM protein function. CCM animal models range from various murine models to zebrafish models, with each model providing unique insights into CCM lesion development and progression. Additionally, these animal models serve as preclinical models to study therapeutic options for CCM treatment. This review briefly summarizes CCM disease pathology and the molecular functions of the CCM proteins, followed by an in-depth discussion of animal models used to study CCM pathogenesis and developing therapeutics.
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Hemangioma Cavernoso do Sistema Nervoso Central , Animais , Hemangioma Cavernoso do Sistema Nervoso Central/genética , Hemangioma Cavernoso do Sistema Nervoso Central/patologia , Camundongos , Proteínas Associadas aos Microtúbulos/metabolismo , Modelos Animais , Mutação , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Peixe-Zebra/genética , Peixe-Zebra/metabolismoRESUMO
Subarachnoid hemorrhage (SAH) is associated with a high incidence of morbidity and mortality, particularly within the first 72 h after aneurysm rupture. We recently found ultra-early cerebral thrombosis, detectable on T2* magnetic resonance imaging (MRI), in a mouse SAH model at 4 h after onset. The current study examined whether such changes also occur in rat at 24 h after SAH, the vessels involved, whether the degree of thrombosis varied with SAH severity and brain injury, and if it differed between male and female rats. Adult Sprague Dawley rats were subjected to an endovascular perforation SAH model or sham surgery and underwent T2 and T2* MRI 24 h later. Following SAH, increased numbers of T2* hypointense vessels were detected on MRI. The number of such vessels correlated with SAH severity, as assessed by MRI-based grading of bleeding. Histologically, thrombotic vessels were found on hematoxylin and eosin staining, had a single layer of smooth muscle cells on alpha-smooth muscle actin immunostaining, and had laminin 2α/fibrinogen double labeling, suggesting venule thrombosis underlies the T2*-positive vessels on MRI. Capillary thrombosis was also detected which may follow the venous thrombosis. In both male and female rats, the number of T2*-positive thrombotic vessels correlated with T2 lesion volume and neurological function, and the number of such vessels was significantly greater in female rats. In summary, this study identified cerebral venous thrombosis 24 h following SAH in rats that could be detected with T2* MRI imaging and may contribute to SAH-induced brain injury.
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Lesões Encefálicas , Trombose Intracraniana , Hemorragia Subaracnóidea , Trombose , Animais , Lesões Encefálicas/complicações , Modelos Animais de Doenças , Feminino , Trombose Intracraniana/complicações , Trombose Intracraniana/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Masculino , Camundongos , Ratos , Ratos Sprague-Dawley , Hemorragia Subaracnóidea/complicações , Hemorragia Subaracnóidea/diagnóstico por imagem , Hemorragia Subaracnóidea/patologia , Trombose/complicações , Trombose/etiologiaRESUMO
AIMS: Iron released from lysed red blood cells within the hematoma plays a role in intracerebral hemorrhage (ICH)-related neurotoxicity. This study utilizes magnetic resonance imaging (MRI) to examine the time course, extent of erythrolysis, and its correlation with perihematomal iron accumulation and white matter loss. METHODS: The feasibility of assessing proportional erythrolysis using T2* MRI was examined using pig blood phantoms with specified degrees of erythrolysis. Fifteen prospectively enrolled ICH patients had MRIs (3-Tesla) at days 1-3, 14, and 30 (termed early, subacute, and late periods, respectively). Measurement was performed on T2*, 1/T2*, and fractional anisotropy (FA) maps. RESULTS: Pig blood phantoms showed a linear relationship between 1/T2* signal and percent erythrolysis. MRI on patients showed an increase in erythrolysis within the hematoma between the early and subacute phases after ICH, almost completing by day 14. Although perihematomal iron overload (IO) correlated with the erythrolysis extent and hematoma volume at days 14 and 30, perihematomal white matter (WM) loss significantly correlated with both, only at day 14. CONCLUSION: MRI may reliably assess the portion of the hematoma that lyses over time after ICH. Perihematomal IO and WM loss correlate with both the erythrolysis extent and hematoma volume in the early and subacute periods following ICH.
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Hemorragia Cerebral/sangue , Eritrócitos/patologia , Sobrecarga de Ferro/sangue , Substância Branca/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Hemorragia Cerebral/diagnóstico por imagem , Feminino , Humanos , Sobrecarga de Ferro/diagnóstico por imagem , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Imagens de Fantasmas , Suínos , Adulto JovemRESUMO
The choroid plexus (CP) is the primary source of cerebrospinal fluid in the central nervous system. Recent evidence indicates that inflammatory pathways at the CP may be involved in hydrocephalus development. Peroxiredoxin 2 (Prx2) is a major component of red blood cells. Extracellular Prx2 is proinflammatory, and its release after red blood cell lysis may contribute to hydrocephalus after intraventricular hemorrhage. This study aimed to identify alterations in CP macrophages and dendritic cells following intracerebroventricular Prx2 injection and investigate the relationship between macrophages/dendritic cells and hydrocephalus. There were two parts to this study. In the first part, adult male Sprague-Dawley rats received an intracerebroventricular injection of Prx2 or saline. In the second part, Prx2 was co-injected with clodronate liposomes or control liposomes. All animals were euthanized at 24 h after magnetic resonance imaging. Immunohistochemistry was used to evaluate macrophages in CP, magnetic resonance imaging to quantify hydrocephalus, and histology to assess ventricular wall damage. The intracerebroventricular injection of Prx2 not only increased the OX-6 positive cells, but it also altered their location in the CP and immunophenotype. Co-injecting clodronate liposomes with Prx2 decreased the number of macrophages and simultaneously attenuated Prx2-induced hydrocephalus and ventricular wall damage. These results suggest that CP macrophages play an essential role in CP inflammation-induced hydrocephalus. These macrophages may be a potential therapeutic target in post-hemorrhagic hydrocephalus.
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Plexo Corióideo/imunologia , Ácido Clodrônico/administração & dosagem , Hidrocefalia/patologia , Peroxirredoxinas/efeitos adversos , Animais , Anticorpos Monoclonais/metabolismo , Modelos Animais de Doenças , Hidrocefalia/induzido quimicamente , Hidrocefalia/imunologia , Infusões Intraventriculares , Lipossomos , Macrófagos/metabolismo , Imageamento por Ressonância Magnética , Masculino , Ratos , Ratos Sprague-DawleyRESUMO
BACKGROUND AND PURPOSE: The mechanisms of brain damage during ultra-early subarachnoid hemorrhage (SAH) have not been well studied. The current study examined the SAH-induced hyperacute brain damage at 4 hours using magnetic resonance imaging and brain histology in a mouse model. METHODS: SAH was induced by endovascular perforation in adult mice. First, adult male wild-type mice underwent magnetic resonance imaging T2 and T2* 4 hours after an endovascular perforation or a sham operation and were euthanized to assess brain histology. Second, male and female adult lipocalin-2 knockout mice had SAH. All animals underwent magnetic resonance imaging at 4 hours, and the brains were harvested for brain histology. RESULTS: T2* hypointensity vessels were observed in the brain 4 hours after SAH in male wild-type mice. The numbers of T2*-positive vessels were significantly higher in SAH brains than in sham-operated mice. Brain histology showed thrombosis and erythrocyte plugs in the T2*-positive cerebral vessels which may be venules. The number of T2*-positive vessels correlated with SAH grade and the presence of T2 lesions. Brain thrombosis was also accompanied by albumin leakage and neuronal injury. LCN2 deficient male mice had lower numbers of T2*-positive vessels after SAH compared with wild-type male mice. CONCLUSIONS: SAH causes ultra-early brain vessel thrombosis that can be detected by T2* gradient-echo sequence at 4 hours after SAH. LCN2 deficiency decreased the number of T2*-positive vessels.
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Trombose Intracraniana/diagnóstico por imagem , Trombose Intracraniana/fisiopatologia , Imageamento por Ressonância Magnética/métodos , Hemorragia Subaracnóidea/diagnóstico por imagem , Hemorragia Subaracnóidea/fisiopatologia , Animais , Modelos Animais de Doenças , Feminino , Processamento de Imagem Assistida por Computador , Trombose Intracraniana/complicações , Lipocalina-2/genética , Lipocalina-2/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Hemorragia Subaracnóidea/complicações , TromboseRESUMO
Intracerebral hemorrhage (ICH) is a stroke subtype with high mortality and severe morbidity. Hemorrhages frequently develop within the white matter, but whether white matter fibers within the hematoma survive after ICH has not been well studied. The current study examines whether white matter fibers persist in the hematoma after ICH, fibers that might be impacted by evacuation, and their relationship to macrophage infiltration in a porcine model. Male piglets had 2.5 ml blood with or without CD47 blocking antibody injected into the right frontal lobe. Brains were harvested from 3 days to 2 months after ICH for brain histology. White matter fibers were detected within the hematoma 3 and 7 days after hemorrhage by brain histology and myelin basic protein immunohistochemistry. White matter still remained in the hematoma cavity at 2 months after ICH. Macrophage scavenger receptor-1 positive macrophages/microglia and heme oxygenase-1 positive cells infiltrated into the hematoma along the intra-hematomal white matter fibers at 3 and 7 days after ICH. Treatment with CD47 blocking antibody enhanced the infiltration of these cells. In conclusion, white matter fibers exist within the hematoma after ICH and macrophages/microglia may use such fibers as a scaffold to infiltrate into the hematoma and aid in hematoma clearance.
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Substância Branca , Animais , Hemorragia Cerebral , Hematoma/etiologia , Macrófagos , Masculino , Microglia , SuínosRESUMO
Peroxiredoxin-2 (PRX-2) is known to be released from erythrocytes and induce brain damage after intracerebral hemorrhage (ICH); lipocalin-2 (LCN-2) is involved in neuroinflammation following ICH. This study examined the role of LCN-2 in PRX-2 induced brain injury and involved three parts. In the first part, adult male C57BL/6 wild-type (WT), LCN-2 heterozygous (LCN-2 HET), and LCN-2 knockout (LCN-2 KO) mice received either an intracaudate injection of recombinant PRX-2 or saline. In the second part, adult male C57BL/6 WT and male LCN-2 KO mice received recombinant PRX-2 with either recombinant mouse LCN-2 protein or control. In the third part, adult female C57BL/6 WT, LCN-2 HET, and LCN-2 KO mice received recombinant PRX-2. Behavioral tests, and T2- and T2*- weighted magnetic resonance imaging was obtained for all mice. Mice were then euthanized, and their brains used for Western blotting, histology and immunohistochemistry. Intracerebral PRX-2 injections resulted in increased expression of LCN-2 protein. PRX-2-induced brain swelling, neutrophil infiltration, microglia/macrophage activation, neuronal cell death, and neurological deficits were reduced in male LCN-2 HET and LCN-2 KO mice (P < 0.01) compared to WT and were exacerbated by exogenous LCN-2 co-injection. Additionally, intracerebral PRX-2 injections caused brain injury and neurological deficits in female WT mice; effects reduced in female LCN-2 KO mice. In conclusion, intracerebral injection of PRX-2 upregulates LCN-2, and LCN-2 is crucial in the effects of PRX-2 on neutrophil infiltration and microglia/macrophage activation, and ultimately brain damage.
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Edema Encefálico/induzido quimicamente , Edema Encefálico/genética , Encefalite/genética , Lipocalina-2/genética , Neurônios/patologia , Peroxirredoxinas , Animais , Comportamento Animal , Edema Encefálico/patologia , Morte Celular/genética , Encefalite/patologia , Feminino , Lipocalina-2/biossíntese , Ativação de Macrófagos/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Infiltração de NeutrófilosRESUMO
AIMS: Over the past two decades, animal intracerebral hemorrhage (ICH) model studies have indicated that iron, released after hemoglobin degradation, is neurotoxic. Iron phantom and animal experiments have shown that magnetic resonance imaging (MRI) relaxivity maps correlate with iron concentration. This study expands this into patients. METHODS: Eighteen human subjects with ICH underwent MRI at 3, 14, and 30 days. R2* relaxivity maps were used to calculate perihematomal iron concentrations and T2 imaging to determine hematoma and edema volumes. RESULTS: Perihematomal iron concentrations were increased at all three time points and decreased with distance from the hematoma. While perihematomal iron concentrations did not vary with hematoma size, the total iron overload (increased iron concentration x volume of affected tissue) did. Total iron overload correlated with edema volume. CONCLUSIONS: These results demonstrate the feasibility of measuring perihematomal iron in ICH patients which may be important for monitoring treatment strategies and assessing efficacy noninvasively.
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Encéfalo/metabolismo , Hemorragia Cerebral/metabolismo , Hematoma/metabolismo , Ferro/metabolismo , Imageamento por Ressonância Magnética/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Encéfalo/diagnóstico por imagem , Hemorragia Cerebral/diagnóstico por imagem , Feminino , Hematoma/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Neutrophils are considered key participants in post-ischemic stroke inflammation. They are the first white blood cells to arrive in ischemic brain and their presence in the brain tissue positively correlates with post-ischemic injury severity. CXCL1 is a neutrophil attractant chemokine and the present study evaluates whether redirecting neutrophil migration using a peripherally implanted CXCL1-soaked sponge can reduce brain inflammation and improve outcomes in a novel mouse model of thromboembolic (TE) stroke. TE stroke was induced by injection of a platelet-rich microemboli suspension into the internal carotid artery of adult C57BL/6 male mice. The model induced neuroinflammation that was associated with increases in multiple brain and serum cytokines/chemokines at the mRNA and protein levels, including very marked increases in CXCL1. In other groups of animals, an absorbable sterile hemostatic sponge, previously immersed in either saline (0.9%NaCl) or CXCL1, was implanted into subcutaneous pockets formed in the inguinal region on the left and right side following stroke surgery. Mice implanted with the sponge soaked with CXCL1 had significantly reduced neuroinflammation and infarct size after TE stroke compared to mice implanted with the sponge soaked with 0.9%NaCl. There was also reduced mortality and improved neurological deficits in the TE stroke + CXCL1 sponge group compared to the TE stroke +0.9%NaCl sponge group. In conclusion: redirecting bloodstream leukocytes toward a peripherally-implanted neutrophil chemokine CXCL1-soaked sponge improves outcomes in a novel mouse model of thromboembolic stroke. The present findings suggest a novel therapeutic strategy for patients with acute stroke.
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Quimiocina CXCL1/farmacologia , Infiltração de Neutrófilos/efeitos dos fármacos , Neutrófilos/metabolismo , Acidente Vascular Cerebral , Tromboembolia , Animais , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Tampões de Gaze CirúrgicosRESUMO
Background and Purpose- Our recent study demonstrated that release of Prx2 (peroxiredoxin 2) from red blood cells (RBCs) is involved in the inflammatory response and brain injury after intracerebral hemorrhage. The current study investigated the role of extracellular Prx2 in hydrocephalus development after experimental intraventricular hemorrhage. Methods- There were 4 parts in this study. First, Sprague-Dawley rats received an intraventricular injection of lysed RBC or saline and were euthanized at 1 hour for Prx2 measurements. Second, rats received an intraventricular injection of Prx2, deactivated Prx2, or saline. Third, lysed RBC was coinjected with conoidin A, a Prx2 inhibitor, or vehicle. Fourth, rats received Prx2 injection and were treated with minocycline or saline (i.p.). The effects of Prx2 and the inhibitors were examined using magnetic resonance imaging assessing ventriculomegaly, histology assessing ventricular wall damage, and immunohistochemistry to assess inflammation, particularly at the choroid plexus. Results- Intraventricular injection of lysed RBC resulted in increased brain Prx2 and hydrocephalus. Intraventricular injection of Prx2 alone caused hydrocephalus, ventricular wall damage, activation of choroid plexus epiplexus cells (macrophages), and an accumulation of neutrophils. Conoidin A attenuated lysed RBC-induced injury. Systemic minocycline treatment reduced the epiplexus cell activation and hydrocephalus induced by Prx2. Conclusions- Prx2 contributed to the intraventricular hemorrhage-induced hydrocephalus, probably by inducing inflammatory responses in choroid plexus and ventricular wall damage.
Assuntos
Hemorragia Cerebral Intraventricular/metabolismo , Plexo Corióideo/metabolismo , Hidrocefalia/metabolismo , Inflamação/metabolismo , Macrófagos/metabolismo , Peroxirredoxinas/metabolismo , Animais , Anti-Inflamatórios/farmacologia , Hemorragia Cerebral Intraventricular/complicações , Plexo Corióideo/efeitos dos fármacos , Plexo Corióideo/patologia , Modelos Animais de Doenças , Epêndima/efeitos dos fármacos , Epêndima/patologia , Feminino , Hidrocefalia/etiologia , Hylobatidae , Inflamação/patologia , Injeções Intraventriculares , Ativação de Macrófagos/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Macrófagos/patologia , Masculino , Minociclina/farmacologia , Neutrófilos/efeitos dos fármacos , Neutrófilos/patologia , Peroxirredoxinas/antagonistas & inibidores , Peroxirredoxinas/farmacologia , Quinoxalinas/farmacologia , Ratos , Ratos Sprague-DawleyRESUMO
With roughly 2 billion people infected, the neurotropic protozoan Toxoplasma gondii remains one of the most pervasive and infectious parasites. Toxoplasma infection is the second leading cause of death due to foodborne illness in the United States, causes severe disease in immunocompromised patients, and is correlated with several cognitive and neurological disorders. Currently, no therapies exist that are capable of eliminating the persistent infection in the central nervous system (CNS). In this study we report the identification of triazine nitrile inhibitors of Toxoplasma cathepsin L (TgCPL) from a high throughput screen and their subsequent optimization. Through rational design, we improved inhibitor potency to as low as 5 nM, identified pharmacophore features that can be exploited for isoform selectivity (up to 7-fold for TgCPL versus human isoform), and improved metabolic stability (t1/2 > 60 min in mouse liver microsomes) guided by a metabolite ID study. We demonstrated that this class of compounds is capable of crossing the blood-brain barrier in mice (1:1 brain/plasma at 2 h). Importantly, we also show for the first time that treatment of T. gondii bradyzoite cysts in vitro with triazine nitrile inhibitors reduces parasite viability with efficacy equivalent to a TgCPL genetic knockout.