endothelin-1 and Hypoxia-Ischemia--Brain

There is a growing body of evidence from clinical and epidemiologic studies that in utero exposure to infection plays an important role in the genesis of fetal or neonatal injury leading to cerebral palsy and chronic lung disease. Thus, after chorioamnionitis the incidence of immature neonates with periventricular white matter damage and periventricular or intraventricular hemorrhage is significantly elevated. Recent clinical and experimental data support the hypothesis that a fetal inflammatory response links antenatal infection with brain white matter damage and subsequent motor handicap. A variety of studies support the view that cytokines released during intrauterine infection directly cause injury to the immature brain. In this review, we provide evidence that in utero exposure to bacterial infection can severely alter fetal cardiovascular function, resulting in dysregulation of cerebral blood flow and subsequent hypoxic-ischemic brain injury.

Topics: Animals; Cardiovascular System; Cerebral Hemorrhage; Cerebral Palsy; Cytokines; Endothelin-1; Endotoxemia; Endotoxins; Female; Fetal Diseases; Humans; Hypoxia-Ischemia, Brain; Infant, Newborn; Infant, Newborn, Diseases; Nitric Oxide; Pregnancy; Pregnancy Complications, Infectious

To observe the changes of endothelin-1 (ET-1), nitrogen oxide (NO) and creatine phosphokinase BB isozyme (CK-BB) in blood and cerebrospinal fluid (CSF) in patients of infantile hypoxic-ishemic encephalopathy (HIE), and explore the efficacy of compound Salvia injection (CSI) in treating mid-severe HIE.. Sixty mid-severe infantile HIE patients were divided randomly into the treated and the control group. To the treated group CSI was added on the basis of conventional treatment, and to the control group the conventional treatment was given alone. The blood and CSF content of ET-1, NO and CK-BB at acute and convalescent stage in the two groups were determined and the therapeutic effects were compared between the two groups.. The markedly effective rate and effective rate of the treated group was 80.0% and 93.3% respectively, while that of the control group was 66.7% and 83.3% respectively, the therapeutic effect in the treated group were obviously superior to that in the control group, the difference was significant (P < 0.05).. ET-1, NO and CK-BB participated the pathological process of HIE. CSI was markedly effective in treating mid and severe HIE infants.

Topics: Creatine Kinase; Creatine Kinase, BB Form; Drugs, Chinese Herbal; Endothelin-1; Female; Humans; Hypoxia-Ischemia, Brain; Infant, Newborn; Isoenzymes; Male; Nitric Oxide; Phytotherapy; Plant Extracts; Salvia miltiorrhiza

Cerebral palsy is an irreversible movement disorder resulting from cerebral damage sustained during prenatal or neonatal brain development. As survival outcomes for preterm injury improve, there is increasing need to model ischemic injury at earlier neonatal time-points to better understand the subsequent pathological consequences. Here we demonstrate a novel neonatal ischemic model using focal administration of the potent vasoconstrictor peptide, endothelin-1 (ET-1), in newborn rats. The functional and histopathological outcomes compare favourably to those reported following the widely used hypoxic ischemia (HI) model. These include a robust motor deficit sustained into adulthood and recapitulation of hallmark features of preterm human brain injury, including atrophy of subcortical white matter and periventricular fiber bundles. Compared to procedures involving carotid artery manipulation and periods of hypoxia, the ET-1 ischemia model represents a rapid and technically simplified model more amenable to larger cohorts and with the potential to direct the locus of ischemic damage to specific brain areas.

Topics: Animals; Animals, Newborn; Brain; Brain Injuries; Disease Models, Animal; Endothelin-1; Female; Hypoxia; Hypoxia-Ischemia, Brain; Pregnancy; Rats

To investigate the levels of endothelial constricting and dilating mediators in preterm infants with hypoxic-ischaemic encephalopathy and prospectively evaluate the association between levels measured during the perinatal period and the diagnosis of neurodevelopmental disorders at 3 years of age.. This regional observational cohort study was conducted at the Azerbaijan Medical University, Baku, Azerbaijan, from November 2011 to January 2013, and comprised very-low-birth-weight infants admitted to the intensive care unit during the perinatal period. Blood concentrations of nitric oxide, endothelin-1 and endothelial nitric oxide synthase were measured on days 1-3 and 5-7 of the neonatal period. Concentrations of neuron-specific enolase and antibodies against N-methyl-D-aspartate glutamate receptors were measured in peripheral blood samples for detection of brain damage in the early neonatal period of life. The infants were divided in 3 different groups: those diagnosed with moderate-to-severe neurodevelopmental disorders or cerebral palsy were included in the first group; those with mild neurologic changes were in the second group; and children without evidence of neurological impairment were in the third group. The fourth group comprised controls. SPSS 20 was used for data analysis.. Of the 62 participants, there were 8(12.9%) in the first group, 20(32.3%) in second, 14(22.6%) in third and 20(32.3%) in the control group. The activity of endothelial nitric oxide synthase was reduced and nitric oxide concentrations were increased in the first group compared to those in the third group (p<0.05). Deep endothelial nitric oxide synthase depression and insufficient endothelin-1 synthesis were associated with diagnosis in the first group (p<0.05). No differences in concentrations of neuron-specific enolase and NR2 antibodies were identified among infants with and without a subsequent diagnosis of neurodevelopmental disorders (p>0.05).. The association between depressed endothelial nitric oxide synthase activation and insufficient endothelin-1 synthesis in the early days of life of very-low-birth-weight infants might be one of the causes of more serious and irreversible injury of brain tissue.

Topics: Azerbaijan; Cerebral Palsy; Developmental Disabilities; Endothelin-1; Female; Fetal Hypoxia; Humans; Hypoxia-Ischemia, Brain; Infant, Newborn; Male; Nitric Oxide; Nitric Oxide Synthase Type III

We have recently demonstrated a role of the vascular endothelium in peripheral pain mechanism by disrupting endothelial cell function using intravascular administration of octoxynol-9, a non-selective membrane active agent. As an independent test of the role of endothelial cells in pain mechanisms, we evaluated the effect of homocysteine, an agent that damages endothelial cell function. Mechanical stimulus-induced enhancement of endothelin-1 hyperalgesia in the gastrocnemius muscle of the rat was first prevented then enhanced by intravenous administration of homocysteine, but was only inhibited by its precursor, methionine. Both homocysteine and methionine significantly attenuated mechanical hyperalgesia in two models of ergonomic muscle pain, induced by exposure to vibration, and by eccentric exercise, and cutaneous mechanical hyperalgesia in an ischemia-reperfusion injury model of Complex Regional Pain Syndrome type I, all previously shown responsive to octoxynol-9. This study provides independent support for a role of the endothelial cell in pain syndromes thought to have a vascular basis, and suggests that substances that are endothelial cell toxins can enhance vascular pain.

Topics: Analgesics, Non-Narcotic; Animals; Cardiovascular Agents; Disease Models, Animal; Endothelin-1; Endothelium, Vascular; Homocysteine; Hyperalgesia; Hypoxia-Ischemia, Brain; Male; Methionine; Movement; Muscle, Skeletal; Myalgia; Rats, Sprague-Dawley; Reflex Sympathetic Dystrophy; Touch; Vibration

Babies are frequently exposed to cerebral hypoxia and ischemia (H/I) during the perinatal period as a result of stroke, problems with delivery or post delivery respiratory management. The sole FDA approved treatment for acute stroke is tissue-type plasminogen activator (tPA). Endogenous tPA is upregulated and potentiates impairment of pial artery dilation in response to hypotension after H/I in pigs. Mitogen-activated protein kinase (MAPK), a family of at least 3 kinases, ERK, p38 and JNK, is also upregulated after H/I, with ERK contributing to impaired vasodilation. This study examined the hypothesis that H/I aggravates the vascular response to two important procontractile mediators released during CNS ischemia, endothelin-1 (ET-1) and thromboxane, which is further enhanced by tPA and ERK MAPK.. Cerebral hypoxia (pO(2) 35 mmHg for 10 min via inhalation of N(2)) followed immediately by ischemia (global intracranial pressure elevation for 20 min) was produced in chloralose anesthetized piglets equipped with a closed cranial window.. H/I aggravated pial artery vasconstriction induced by ET-1 and the thromboxane mimetic U 46619. Potentiated vasoconstrictor responses were blocked by EEIIMD, an inhibitor of tPA's signaling and vascular activities, but unchanged by its inactive analogue EEIIMR. The cerebrospinal fluid concentration of ERK MAPK determined by ELISA was increased by H/I, potentiated by tPA, but blocked by EEIIMD. The ERK MAPK antagonist U 0126 blocked H/I augmented enhancement of ET-1 and U 46619 vasoconstriction.. These data indicate that H/I aggravates ET-1 and thromboxane mediated cerebral vasoconstriction by upregulating endogenous tPA and ERK MAPK.

Topics: Animals; Animals, Newborn; Brain; Cerebrovascular Circulation; Craniotomy; Disease Models, Animal; Endothelin-1; Female; Hypoxia-Ischemia, Brain; Male; Oligopeptides; Pia Mater; Plasminogen Activator Inhibitor 1; Swine; Thromboxanes; Translational Research, Biomedical; Vasoconstriction; Vasoconstrictor Agents

Recovery of brain lesions has been associated with increased activation and migration of endogenous neural stem cells, glia, and endothelium. To understand the role of endothelinergic signaling in these phenomena we studied devascularizing lesions of mouse brain cortex. Our specific aims were to: (i) describe the endothelinergic cell phenotypes appearing within the lesions; and (ii) evaluate the effect of endothelinergic blockade on the injured cortex.. C57BL/6 mice were anesthetized and submitted to devascularization lesions of the right M1 cortical area. A group of mice was daily treated with tezosentan, a dual endothelinergic receptor blocker. Mice were euthanatized 5 days after surgery and the injured area was studied with immunohistochemistry for endothelin, endothelin receptor B, glial fibrillary acidic protein, prominin-1, nestin, and phospho-histone H3.. The injured cortex exhibited a large increase of multipolar endothelin(+), endothelin receptor B(+), glial fibrillary acidic protein(+), prominin-1(+), and nestin(+) cells. These markers appeared in different combinations. Tezosentan treatment reduced the perilesional expression of glial fibrillary acidic protein and decreased the number of proliferating cell nuclei displaying phospho-histone H3.. Our observations suggest that endothelinergic cells surrounding the lesion belong to a mixed population including reactive glia and neural progenitor cells. Findings in tezosentan-treated mice probably reflect a decrease of reactive gliosis with a still unknown effect on neural progenitor cells.

Topics: Animals; Disease Models, Animal; Endothelin A Receptor Antagonists; Endothelin B Receptor Antagonists; Endothelin-1; Hypoxia-Ischemia, Brain; Infarction, Middle Cerebral Artery; Male; Mice; Mice, Inbred C57BL; Neuroglia; Receptor, Endothelin A; Receptor, Endothelin B; Recovery of Function; Signal Transduction; Stem Cells

Previous studies have showed that vascular endothelial growth factor (VEGF) displayed neurotrophic and neuroprotective activities. To examine whether target delivery of VEGF gene directly into brain may prevent ischemic brain damage, the VEGF expression adenoviral vectors, AVHP.VEGF-with 476bp of the human preproendothelin-1 (ppET-1) promoter and 35bp of the hypoxia-reponse element (HRE) driving VEGF expression and CMV.VEGF were transferred into hypoxic-induced ischemic (HI) rat brains. Seven-day-old rats that were underwent left carotid ligation followed by 2h of hypoxic stress (8% O(2) at 37 degrees C) were received VEGF adenoviral vectors or buffer (PBS) injection 3 days after HI. The body weight, VEGF expression, neuronal apoptosis, cerebral morphology and brain functional assays were performed between 7 and 28 days after HI. There were remarkable increases in the body weight and VEGF protein expression, and decrease in the number of TUNEL-positive cells in the VEGF vector groups as compared with PBS group. The VEGF vector groups also had better brain functional performs than PBS group. The better performs by the animals that received VEGF vectors may be directly linked to the inhibitory effect of VEGF on neuronal apoptosis because the animals had less neural loss in the cortex and hippocampal CA1 region as compared with PBS group. Overall, these results indicated that over-expression of VEGF in the brain exerted a neuroprotective effect and promoted neural functional recovery in neonatal rats after hypoxic-ischemic brain damage, suggesting that in vivo target VEGF gene transfer to brain may be a promising approch for the treatment of such implications.

Topics: Adenoviridae; Animals; Animals, Newborn; Apoptosis; Body Weight; Brain; Endothelin-1; Genetic Vectors; Humans; Hypoxia-Ischemia, Brain; Neurons; Promoter Regions, Genetic; Rats; Rats, Sprague-Dawley; Recovery of Function; Time Factors; Transduction, Genetic; Treatment Outcome; Vascular Endothelial Growth Factor A

The serine protease thrombin has shown direct neuroprotective and neurotoxic effects on brain tissue in cerebral ischemia. Previous data suggested that thrombin-induced protection in vivo can be achieved by preconditioning rather than by acute treatment. In the current work, we used a model of mild ischemia to investigate the effects of preischemic intracerebral thrombin injection on neural damage. By intracerebral injection of endothelin-1 in freely moving animals, we achieved middle cerebral artery occlusion (MCAO), and 7 days postischemia we performed histological quantification of the infarct areas. Thrombin was injected as a preconditioning stimulus intracerebrally 7 days or 2 and 3 days before ischemia. For acute treatment, thrombin was injected 20 min before MCAO. Thrombin induced significant neuroprotection when given 7 days before endothelin-1-induced MCAO but was deleterious when given 2 and 3 days before the insult. The deleterious effect was not seen when thrombin was given acutely before ischemia. Our data demonstrate that preconditioning with thrombin can protect against damage or worsen ischemic damage. Its effect depended on the time interval between thrombin injection and insult. A low dose of thrombin did not induce a major deleterious effect in the acute phase of the infarct development after mild transient ischemia.

Topics: Animals; Behavior, Animal; Brain Infarction; Disease Progression; Dose-Response Relationship, Drug; Drug Administration Schedule; Endothelin-1; Hemostatics; Hypoxia-Ischemia, Brain; Male; Rats; Rats, Sprague-Dawley; Statistics, Nonparametric; Thrombin; Time Factors

The direct injection of endothelin-1 (ET-1) into brain parenchyma was recently suggested as a suitable model of stroke. The present study was designed to assess whether intrahippocampal injection of ET-1 in immature rats causes neurodegeneration and immediate seizures, and results in impairment of motor development, cognitive decline, epilepsy and chronic hippocampal lesion. ET-1 was injected unilaterally into the dorsal hippocampus in doses of 20 or 40 pmol at the age of 12 (P12) or 25 (P25) days. Video-electroencephalographic monitoring performed during 100 min after the injection of ET-1 demonstrated the development of convulsive epileptic seizures in 75-100% of animals of individual age-and-dose groups. Long-term behavioral follow-up did not reveal impairment of motor development in any dose-and-age group. At 2 months after ET-1 injection, impairment of spatial memory occurred only in rats with 40 pmol of ET-1 at P12. At 3 months after ET-1 injection spontaneous electrographic seizures occurred in 62.5-100% animals of both ages with no relation to the dose used. Seizures were always non-convulsive. The total seizure duration per 24 h was higher in the P12 than the P25 group, suggesting more severe epilepsy. The extent of the hippocampal lesion increased with the dose of ET-1 and was significantly higher in the P12 than the P25 group. The severity of the ET-1-induced lesion correlated positively with total seizure duration per 24 h at both ages. Our results document that early intrahippocampal injection of ET-1 results in lesion development and both immediate seizures and chronic epilepsy in either age group. Cognitive impairment occurred only in rats with ET-1 injection at P12.

Topics: Age Factors; Animals; Animals, Newborn; Cerebral Arteries; Cerebrovascular Circulation; Developmental Disabilities; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Administration Schedule; Electroencephalography; Endothelin-1; Epilepsy; Hippocampus; Humans; Hypoxia-Ischemia, Brain; Infant, Newborn; Male; Memory Disorders; Nerve Degeneration; Rats; Rats, Wistar; Stroke; Vasoconstrictor Agents

Amoeboid microglial cells (AMC) which transiently exist in the corpus callosum in the postnatal rat brain expressed endothelins (ETs), specifically endothelin-1 (ET-1) and ET3 as revealed by real time RT-PCR. ET immunoreactive AMC occurred in large numbers at birth, but were progressively reduced with age and were undetected in 14 days. In rats subjected to hypoxia exposure, ET immunoexpression in AMC was reduced but the incidence of apoptotic cells was not increased when compared with the control suggesting that this was due to its downregulation that may help regulate the constriction of blood vessels bearing ET-A receptor. AMC were endowed ET-B receptor indicating that ET released by the cells may also act via an autocrine manner. In microglia activated by lipopolysaccharide (LPS), ET-1 mNA expression coupled with that of monocyte chemoattractant protein (MCP-1) and stromal derived factor-1 (SDF-1) was markedly increased; ET-3 mRNA, however, remained unaffected. AMC exposed to oxygen glucose deprivation (OGD) in vitro resulted in increase in both ET-1 and ET-3 mRNA expression. It is suggested that the downregulated ETs expression in vivo of AMC subjected to hypoxia as opposed to its upregulated expression in vitro may be due to the complexity of the brain tissue. Furthermore, the differential ET-1 and ET-3 mRNA expression in LPS and OGD treatments may be due to different signaling pathways independently regulating the two isoforms. The present novel finding has added microglia as a new cellular source of ET that may take part in multiple functions including regulating vascular constriction and chemokines release.

Topics: Animals; Animals, Newborn; Brain; Cell Differentiation; Cell Movement; Cells, Cultured; Down-Regulation; Endothelin-1; Endothelin-3; Endothelins; Female; Gene Expression Regulation, Developmental; Hypoxia-Ischemia, Brain; Male; Microcirculation; Microglia; Microscopy, Electron, Transmission; Rats; Rats, Sprague-Dawley; Receptors, Endothelin; RNA, Messenger; Vasoconstriction

Under pathological conditions in the adult CNS, such as ischemia, subarachnoid hemorrhage and Alzheimer's disease, endothelin (ET)-1- and -3-like immunoreactivities are elevated in astrocytes of the injured adult brain. However, it is not clear whether this is due to increased synthesis or increased binding of ET-1. Further, it is not known whether ET-1 expression is altered in the perinatal brain after cerebral hypoxia/ischemia (H/I). Here, we determined the sites of ET-1 expression in perinatal mouse brain after H/I injury by in situ hybridization using a probe specific for the ET-1 gene. Astrocyte-like cells, which do not normally express ET-1 mRNA, showed high levels of ET-1 mRNA expression. Endothelial cells of the capillaries and small vessels also showed an increased level of ET-1 mRNA. Our data suggest that ET-1 mRNA levels in the astrocyte-like cells and vascular endothelial cells are dynamically regulated by ischemia and may participate in perinatal ischemia-related neural damage.

Topics: Animals; Animals, Newborn; Astrocytes; Brain; Brain Chemistry; Cell Death; Endothelin-1; Endothelium, Vascular; Hypoxia-Ischemia, Brain; Mice; Mice, Inbred C57BL; RNA, Messenger