endothelin-1 and Stroke

Endothelin (ET)-1 is a potent vasoconstrictor peptide produced by endothelial cells and associated with vascular dysfunction and cardiovascular disease. Lys198Asn is a single-nucleotide polymorphism (SNP) of gene encoding ET-1 (EDN1). It is hypothesized that it might have a role in altering ET-1 and ultimately leading to vascular dysfunction and ischemic stroke. We therefore conducted a meta-analysis to investigate the association between Lys198Asn polymorphism of EDN1 gene and susceptibility of ischemic stroke.. This meta-analysis was conducted according to the guidance of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. We searched PubMed, Google Scholar, Embase, Web of Science, J-STAGE, and China National Knowledge Infrastructure (CNKI) for relevant studies. The association between Lys198Asn polymorphism and ischemic stroke susceptibility was evaluated by calculating the pooled ORs and 95% CIs.. Our analysis included 1,291 cases and 2,513 controls. Meta-analysis established a significant association between Lys198Asn SNP of EDN1 gene and ischemic stroke when assuming either recessive model (OR: 1.30; 95% CI: 1.02-1.65; p = .03; I. The present meta-analysis suggests that Lys198Asn polymorphism of EDN1 gene is associated with an increased risk for ischemic stroke.

Topics: Brain Ischemia; Endothelin-1; Genetic Predisposition to Disease; Humans; Polymorphism, Single Nucleotide; Stroke

Multiple methods exist to model permanent and transient ischemia under anesthesia in animals, however most human strokes occur while conscious. The use of endothelin-1 as a vasoconstrictor applied to the perivascular surface of the middle cerebral artery is one of the only methods for inducing stroke in conscious animals. Here, we describe standard operating procedures for stereotaxic placement of an ET-1 guide probe above the middle cerebral artery, induction of stroke in conscious rats, predictive outcome scoring during stroke, and neurological behavioral tests that we use to monitor transient and continuing deficits. The inclusion of long term neurological assessment is of particular importance when taking into consideration the effects of stroke on brain remodeling.

Topics: Acute Disease; Animals; Brain; Consciousness; Disease Models, Animal; Endothelin-1; Humans; Rats; Stroke

Retinal vein occlusion (RVO) is a common vascular disease of retina; however, the pathomechanism leading to RVO is not yet clear. In general, increasing age, hypertension, arteriosclerosis, diabetes mellitus, dyslipidemia, cardiovascular disorder, and cerebral stroke are systemic risk factors of RVO. However, RVO often occur in the unilateral eye and sometimes develop in young subjects who have no arteriosclerosis. In addition, RVO show different variations on the degrees of severity; some RVO are resolved without any treatment and others develop vision-threatening complications such as macular edema, combined retinal artery occlusion, vitreous hemorrhage, and glaucoma. Clinical conditions leading to RVO are still open to question. In this review, we discuss how to treat RVO in practice by presenting some RVO cases. We also deliver possible pathomechanisms of RVO through our clinical experience and animal experiments.

Topics: Animals; Arteriosclerosis; Diabetes Complications; Dyslipidemias; Endothelin-1; Humans; Hypertension; Retina; Retinal Vein Occlusion; Risk Factors; Stroke; Veins

Ischemic stroke causes vascular paralysis and impaired autoregulation in the brain, the degree of which is dependent on the depth and duration of ischemia and reperfusion (I/R). Ischemic stroke also impairs the myogenic response of middle cerebral arteries (MCA) that may be an underlying mechanism by which autoregulation is impaired. Myogenic responses are affected by I/R through several mechanisms, including production of peroxynitrite, depolymerization of F-actin in vascular smooth muscle, and circulating vasoactive factors. The vascular endothelium is also significantly affected during focal ischemia that has a particularly large influence on vascular tone in the cerebral circulation. Endothelial nitric oxide (NO) and endothelin-1 (ET-1) are important endothelium-dependent vasoactive substances that can influence the level of myogenic tone in cerebral arteries and arterioles that are significantly affected during ischemic stroke. Unlike MCA, brain penetrating arterioles have considerable myogenic tone that appears less affected by focal ischemia. The persistent tone of brain parenchymal arterioles during focal ischemia could contribute to perfusion deficit and infarct expansion. These arterioles within the cerebral cortex are also unique from MCA in that they constrict to small- and intermediate- conductance calcium-activated potassium channel (SKCa and IKCa, respectively) inhibition, suggesting basal endothelium-derived hyperpolarizing factor (EDHF) is preserved during focal ischemia. This review will highlight our current understanding of the effects of I/R on myogenic response in both MCA and parenchymal arterioles and discuss underlying mechanisms by which focal ischemia affects myogenic tone in these different vascular segments.

Topics: Animals; Brain Ischemia; Cerebrovascular Circulation; Drug Delivery Systems; Endothelin-1; Homeostasis; Humans; Muscle, Smooth, Vascular; Nitric Oxide; Stroke; Vasodilator Agents

Lacunar ischemic stroke accounts for 25% of all ischemic strokes, but the exact etiology is unknown. Numerous pathophysiologies have been proposed, including atheroma and endothelial dysfunction. Models of any of these pathological features would aid understanding of the etiology and help develop treatments for lacunar stroke. We therefore aimed to assess the relevance of all available potential animal models of lacunar stroke.. We systematically reviewed the published literature for animal models that could represent lacunar stroke using validated search strategies. We included studies that could represent an aspect of lacunar stroke as well as those aiming to model conditions with potentially similar pathology and extracted data on species, induction method, and resulting brain and vessel lesions.. From 5670 papers, 41 studies (46 papers) met inclusion criteria representing over 10 different classes of stroke induction. Important data like infarct size and animal numbers were often missing. Many models' infarcts were too large or affected the cortex. Emboli mostly caused cortical but not small subcortical lesions. Most models focused on creating ischemic lesions in brain tissue. Only one (spontaneous lesions in spontaneously hypertensive stroke-prone rats) also mimicked small vessel pathology. Here, the precursor to small vessel and brain damage was blood-brain barrier failure.. Some animal models produce small subcortical infarcts, but few mimic the human small vessel pathology. Models of small vessel disease could help improve understanding of human lacunar disease, particularly to clarify factors associated with the small vessel morphological changes preceding brain damage. Much lacunar stroke may arise after blood-brain barrier disruption.

Topics: Animals; Arterial Occlusive Diseases; Brain Ischemia; Cerebral Arteries; Data Interpretation, Statistical; Disease Models, Animal; Endothelin-1; Humans; Infarction, Middle Cerebral Artery; Intracranial Embolism; Stroke

Stroke is the third most common cause of death in developed countries. In England and Wales, 1000 people under the age of 30 have a stroke each year. Cocaine is the most commonly used class A drug, and the first report of cocaine-induced stroke was in 1977. Since the development of alkaloidal "crack" cocaine in the 1980s, there has been a significant rise in the number of case reports describing both ischaemic and haemorrhagic stroke associated with cocaine use. Cocaine is a potent central nervous system stimulant, and acts by binding to specific receptors at pre-synaptic sites preventing the reuptake of neurotransmitters. The exact mechanism of cocaine-induced stroke remains unclear and there are likely to be a number of factors involved including vasospasm, cerebral vasculitis, enhanced platelet aggregation, cardioembolism, and hypertensive surges associated with altered cerebral autoregulation. The evidence surrounding each of these factors will be considered here.

Topics: Animals; Cocaine; Cocaine-Related Disorders; Endothelin-1; Humans; Stroke; Vasospasm, Intracranial

Stroke remains the leading cause of adult disability, with upper extremity motor impairments being the most prominent functional deficit in surviving stroke victims. The development of animal models of upper extremity dysfunction after stroke has enabled investigators to examine the neural mechanisms underlying rehabilitation-dependent motor recovery as well as the efficacy of various adjuvant therapies for enhancing recovery. Much of this research has focused on rat models of forelimb motor function after experimentally induced ischemic or hemorrhagic stroke. This article provides a review of several different methods for inducing stroke, including devascularization, photothrombosis, chemical vasoconstriction, and hemorrhagia. We also describe a battery of sensorimotor tasks for assessing forelimb motor function after stroke. The tasks range from measures of gross motor performance to fine object manipulation and kinematic movement analysis, and we offer a comparison of the sensitivity for revealing motor deficits and the amount of time required to administer each motor test. In addition, we discuss several important methodological issues, including the importance of testing on multiple tasks to characterize the nature of the impairments, establishing stable baseline prestroke motor performance measures, dissociating the effects of acute versus chronic testing, and verifying lesion location and size. Finally, we outline general considerations for conducting research using rat models of stroke and the role that these models should play in guiding clinical trials.

Topics: Animals; Behavioral Symptoms; Disease Models, Animal; Endothelin-1; Infarction, Middle Cerebral Artery; Rats; Research Design; Stroke; Stroke Rehabilitation; Upper Extremity

Pathophysiology of endothelin-1, a vasoconstrictor and a mitogenic peptide, has been extensively investigated in recent years. The authors have examined the main clinical and experimental evidence regarding the involvement of this peptide in some medical emergencies, namely myocardial infarction, stroke and hepato-renal syndrome. Literature data suggest an emerging pathophysiological role for endothelin in such clinical conditions.

Topics: Emergencies; Endothelin-1; Hepatorenal Syndrome; Humans; Myocardial Infarction; Stroke

Our understanding of the role of the endothelin system in human cardiovascular physiology and pathophysiology has evolved very rapidly since the initial description of its constituent parts in 1988. Endothelin-1 (ET-1) is the predominant endothelin isoform in the human cardiovascular system and has potent vasoconstrictor, mitogenic and antinatriuretic properties which have implicated it in the pathophysiology of a number of cardiovascular diseases. The effects of ET-1 have been shown to be mediated by 2 principal endothelin receptor subtypes: ET(A) and ET(B). The development of a range of peptidic and nonpeptidic endothelin receptor antagonists represents an exciting breakthrough in human cardiovascular therapeutics. Two main classes of endothelin receptor antagonist have been developed for possible human therapeutic use: ET(A)-selective and nonselective antagonists. Extensive laboratory and clinical research with these agents has highlighted their promise in various cardiovascular diseases. Randomised, placebo-controlled clinical trials have yielded very encouraging results in patients with hypertension and chronic heart failure with more preliminary data suggesting a possible role in the treatment and prevention of atherosclerosis and stroke. Much more research is needed, however, before endothelin receptor antagonists can be considered for clinical use.

Topics: Aged; Animal Population Groups; Animals; Arteriosclerosis; Cardiovascular Diseases; Drugs, Investigational; Endothelin Receptor Antagonists; Endothelin-1; Heart Failure; Humans; Hypertension, Pulmonary; Receptors, Endothelin; Stroke

Multiple endocrine abnormalities have been reported in stroke patients. In the past few years, it has been claimed that some of these abnormalities may play a role in worsening the neurological deficit and the outcome of stroke. Several mechanisms have been hypothesised, including a direct effect on the development of neuronal cell death, vasospasm, and development of brain edema. In this brief review, we discuss the current knowledge concerning the role of endothelin-1, arginine vasopressin, and cortisol in the pathogenesis of stroke. Finally, we discuss the possibility that leptin, the OB gene product, may be the link of some of these endocrine abnormalities, and that its abnormal secretion during stroke may contribute to the eating disorders and poor nutritional status often seen in these patients.

Topics: Arginine Vasopressin; Brain Ischemia; Endocrine System Diseases; Endothelin-1; Humans; Hydrocortisone; Hypothalamus; Leptin; Pituitary-Adrenal System; Stroke

Endothelial cells play a key role in the local regulation of the vascular smooth muscle tone by producing and releasing relaxing and contracting factors. Endothelin (ET)-1, one of the most potent endogenous vasoconstrictor substances known, is produced by endothelial cells. In the cerebral vasculature ET-1 is thought to be involved in several pathological conditions, including vasospasm following subarachnoid hemorrhage and stroke. This review contains evidence suggesting that endothelial dysfunction may contribute to the development of ischemic stroke and discusses the current knowledge concerning the role of ET-1 in the pathogenesis of stroke in animal models and in humans.

Topics: Animals; Aspartic Acid Endopeptidases; Brain Ischemia; Cerebrovascular Circulation; Endothelin Receptor Antagonists; Endothelin-1; Endothelin-Converting Enzymes; Endothelium, Vascular; Genetic Predisposition to Disease; Humans; Metalloendopeptidases; Receptors, Endothelin; Stroke

To observe clinical therapeutic effect of sequential acupuncture method on apoplexy hemiplegia and to probe into the mechanism.. One hundred and forty-four cases of apoplexy hemiplegia were randomly divided into a treatment group treated with sequential acupuncture method and a control group treated with traditional acupuncture, 72 cases in each group. After treatment for 3 months, their clinical therapeutic effects were observed and plasma endothelin-1 (ET-1) and nitric oxide (NO) levels were detected.. The treatment group in the improvement of the nerve function-deficiency, total life ability and clinical overall effect, and the course of recovery, decreasing of ET-1 level and increasing of NO level was superior to the control group (P < 0.05, P < 0.01), the shorter the course, the better the therapeutic effect.. The sequential acupuncture method has an obvious therapeutic effect on apoplexy hemiplegia, and it can decrease plasma ET-1 level and increase NO level. It is an effective therapy for apoplexy hemiplegia.

Topics: Acupuncture Therapy; Adult; Endothelin-1; Female; Hemiplegia; Humans; Male; Middle Aged; Nitric Oxide; Stroke

Endothelin-1 (ET-1) is a potent and long-acting vasoconstrictor peptide, which may play a role in the pathophysiology of a number of diseases. Controversial data exist on its role in human ischemic stroke. In order to ascertain whether changes in ET-1 plasma levels occur in ischemic stroke, plasma ET-1 levels and mean arterial pressure were determined in 15 patients at their first ischemic cerebral infarction and in 15 control subjects, over a 24-hour period. In stroke patients, mean 24-hour plasma ET-1 levels (4.9+/-0.5 ng/L) were higher (P< 0.05) than in control subjects (3.2+/-0.3 ng/L), and correlated with the mean size of the lesion, but not with the severity score of the neurological deficit. These results support the hypothesis that ET-1 levels reflect an indicator function for the amount of damaged cerebral tissue rather than a pathophysiological role.

Topics: Aged; Blood Pressure; Circadian Rhythm; Endothelin-1; Female; Humans; Male; Middle Aged; Radioimmunoassay; Stroke

Stroke cachexia is associated with prolonged inflammation, muscle loss, poor prognosis, and early death of stroke patients. No particular treatment is available to cure the symptoms or disease. The present study aimed to evaluate the effect of a 5-HT1a agonist, buspirone on stroke cachexia. Wistar rats were injected with endothelin-1 to the bregma region of the brain to induce ischemic stroke followed by induction of cachexia after 4 days. Treatment with buspirone (3 mg/kg p.o) was given for 4 weeks after confirmation of cachexia in animals. Disease control animals exhibited decrease in wire hanging time and increase in foot fault numbers compared to normal animals. Disease control animals also showed weight loss, decrease in food intake, increased serum glucose and lipid profile along with high serum levels of inflammatory cytokines-TNF-α, IL-6 and decrease in weight of skeletal muscle and adipose tissues. Treatment with buspirone improves behavioural parameters along with increases food intake and body weight, decreased inflammatory cytokines IL-6 and TNF-α and serum glucose levels with increase in lipid profile. Buspirone also increased the weight of adipose tissue and maintain the skeletal muscle architecture and function as depicted in histopathological studies. Our study suggests that buspirone produces beneficial role in stroke cachexia by increasing body weight, food intake and adipose tissue depots by activating on 5-HT receptors. Buspirone decreases inflammatory markers in stroke cachexia although mechanism behind it was not fully understood. Buspirone decreases circulating blood glucose by stimulating glucose uptake in skeletal muscle via 5-HT receptors and maintained lipid profile. Buspirone was found to be effective in ameliorating cachectic conditions in stroke.

Topics: Animals; Buspirone; Cachexia; Cytokines; Endothelin-1; Glucose; Interleukin-6; Lipids; Muscle, Skeletal; Rats; Rats, Wistar; Stroke; Tumor Necrosis Factor-alpha

Retinal vein occlusion (RVO) risk factors largely coincide with cardiovascular risk factors. Endothelin-1 (ET-1), the most potent vasoconstrictor with proinflammatory properties, is a known cardiovascular risk factor. In this study, we explore the role of serum ET-1 as a potential risk factor for RVO.. Endothelin-1 serum levels were measured in patients with RVO and control subjects. Samples were measured using the sandwich enzyme-linked immunosorbent assay for the quantitative determination of human big endothelin-1 (Biomedica Group, Austria).. The study consisted of 147 RVO patients and 150 control subjects. Median serum ET-1 was significantly higher in RVO patients (0.26 pmol/L; range, 0.19-0.37 pmol/L) compared with control subjects (0.10 pmol/L; range, 0.05-0.22 pmol/L) (P < 0.0001) independent of the occlusion site. The difference remained significant after adjusting for arterial hypertension, diabetes mellitus, history of stroke, history of myocardial infarction, history of venous thromboembolism, glomerular filtration rate, and c-reactive protein.. In conclusion, our results suggest that ET-1 is a potential risk factor for all types of RVO.

Topics: Endothelin-1; Humans; Hypertension; Retinal Vein Occlusion; Risk Factors; Stroke

The brain-gut axis is a major regulator of the central nervous system. We investigated the effects of treatment with broad-spectrum antibiotics on gut and brain inflammation, infarct size and long-term behavioral outcome after cerebral ischemia in rats.. Rats were treated with broad-spectrum antibiotics (ampicillin, vancomycin, ciprofloxacin, meropenem and metronidazole) for 4 weeks before the endothelin-1 induced ischemia. Treatment continued for 2 weeks until the end of behavioral testing, which included tapered ledged beam-walking, adhesive label test and cylinder test. Gut microbiome, short-chain fatty acids and cytokine levels were measured together with an assessment of infarct size, neuroinflammation and neurogenesis.. The results revealed that the antibiotics exerted a clear impact on the gut microbiota. This was associated with a decrease in systemic and brain cytokine levels, infarct size and apoptosis in the perilesional cortex and improved behavioral outcome.. Our results highlighted the significant relationship between intestinal microbiota and beneficial neuro-recovery after ischemic stroke.

Topics: Ampicillin; Animals; Anti-Bacterial Agents; Ciprofloxacin; Cytokines; Endothelin-1; Fatty Acids, Volatile; Gastrointestinal Microbiome; Infarction; Meropenem; Metronidazole; Rats; Stroke; Vancomycin

The endothelin-1 (ET-1) model of stroke involves the stereotactic injection of the vasoconstrictor ET-1 to produce a focal ischemic injury. In rats, this model produces consistent deficits, in contrast to more variable results in mice. In this chapter, we describe a new method to induce a murine focal ischemic cortical stroke by injecting L-NAME, another potent vasoconstrictor , in combination with ET-1 into the sensorimotor cortex. This ET-1 /L-NAME stroke induction protocol produces consistent focal cortical infarcts and sensorimotor functional impairments in C57BL/6 mice.

Topics: Animals; Disease Models, Animal; Endothelin-1; Mice; Mice, Inbred C57BL; NG-Nitroarginine Methyl Ester; Rats; Stroke; Vasoconstrictor Agents

Topics: Animals; Brain; Brain Ischemia; Endothelin-1; Heart Diseases; Infarction, Middle Cerebral Artery; Inflammation; Mice; Molecular Imaging; Positron-Emission Tomography; Stroke; Vasoconstrictor Agents

Multiple sclerosis is a chronic inflammatory demyelinating disease of the central nervous system (CNS), characterized by accumulated motor disability. However, whether remyelination promotes motor recovery following demyelinating injury remains unclear. Damage to the internal capsule (IC) is known to result in motor impairment in multiple sclerosis and stroke. Here, we induced focal IC demyelination in mice by lysophosphatidylcholine (LPC) injection, and examined its effect on motor behavior. We also compared the effect of LPC-induced IC damage to that produced by endothelin-1 (ET1), a potent vasoconstrictor used in experimental stroke lesions. We found that LPC or ET1 injections induced asymmetric motor deficit at 7 days post-lesion (dpl), and that both lesion types displayed increased microglia/macrophage density, myelin loss, and axonal dystrophy. The motor deficit and lesion pathology remained in ET1-injected mice at 28 dpl. In contrast, LPC-injected mice regained motor function by 28 dpl, with corresponding reduction in activated microglia/macrophage density, and recovery of myelin staining and axonal integrity in lesions. These results suggest that LPC-induced IC demyelination results in acute motor deficit and subsequent recovery through remyelination, and may be used to complement future drug screens to identify drugs for promoting remyelination.

Topics: Animals; Axons; Demyelinating Diseases; Endothelin-1; Immunohistochemistry; Internal Capsule; Lysophosphatidylcholines; Macrophages; Male; Mice; Mice, Inbred C57BL; Microglia; Motor Skills Disorders; Myelin Sheath; Oligodendroglia; Recovery of Function; Stroke

Ischemia is one of the most common causes of acquired brain injury. Central to its noxious sequelae are spreading depolarizations (SDs), waves of persistent depolarizations which start at the location of the flow obstruction and expand outwards leading to excitotoxic damage. The majority of acute stage of stroke studies to date have focused on the phenomenology of SDs and their association with brain damage. In the current work, we investigated the role of peri-injection zone pyramidal neurons in triggering SDs by optogenetic stimulation in an endothelin-1 rat model of focal ischemia. Our concurrent two photon fluorescence microscopy data and local field potential recordings indicated that a ≥ 60% drop in cortical arteriolar red blood cell velocity was associated with SDs at the ET-1 injection site. SDs were also observed in the peri-injection zone, which subsequently exhibited elevated neuronal activity in the low-frequency bands. Critically, SDs were triggered by low- but not high-frequency optogenetic stimulation of peri-injection zone pyramidal neurons. Our findings depict a complex etiology of SDs post focal ischemia and reveal that effects of neuronal modulation exhibit spectral and spatial selectivity.

Topics: Animals; Cortical Spreading Depression; Disease Models, Animal; Endothelin-1; Rats; Stroke

Serum biomarkers are associated with hemorrhagic transformation and brain edema after cerebral infarction. However, whether serum biomarkers predict hemorrhagic transformation in large vessel occlusion stroke even after mechanical thrombectomy, which has become widely used, remains uncertain. In this prospective study, we enrolled patients with large vessel occlusion stroke in the anterior circulation. We analyzed 91 patients with serum samples obtained on admission. The levels of matrix metalloproteinase-9 (MMP-9), amyloid precursor protein (APP) 770, endothelin-1, S100B, and claudin-5 were measured. We examined the association between serum biomarkers and hemorrhagic transformation within one week. Fifty-four patients underwent mechanical thrombectomy, and 17 patients developed relevant hemorrhagic transformation (rHT, defined as hemorrhagic changes ≥ hemorrhagic infarction type 2). Neither MMP-9 (no rHT: 46 ± 48 vs. rHT: 15 ± 4 ng/mL, P = 0.30), APP770 (80 ± 31 vs. 85 ± 8 ng/mL, P = 0.53), endothelin-1 (7.0 ± 25.7 vs. 2.0 ± 2.1 pg/mL, P = 0.42), S100B (13 ± 42 vs. 12 ± 15 pg/mL, P = 0.97), nor claudin-5 (1.7 ± 2.3 vs. 1.9 ± 1.5 ng/mL, P = 0.68) levels on admission were associated with subsequent rHT. When limited to patients who underwent mechanical thrombectomy, the level of claudin-5 was higher in patients with rHT than in those without (1.2 ± 1.0 vs. 2.1 ± 1.7 ng/mL, P = 0.0181). APP770 levels were marginally higher in patients with a midline shift ≥ 5 mm than in those without (79 ± 29 vs. 97 ± 41 ng/mL, P = 0.084). The predictive role of serum biomarkers has to be reexamined in the mechanical thrombectomy era because some previously reported serum biomarkers may not predict hemorrhagic transformation, whereas the level of APP770 may be useful for predicting brain edema.

Topics: Aged; Aged, 80 and over; Amyloid beta-Protein Precursor; Biomarkers; Brain Edema; Cerebral Infarction; Cerebrovascular Disorders; Claudin-5; Endothelin-1; Female; Gene Expression; Humans; Male; Matrix Metalloproteinase 9; Predictive Value of Tests; Prospective Studies; S100 Calcium Binding Protein beta Subunit; Stroke; Thrombectomy

The aim: Investigate the effect of Lys198Asn polymorphism of the EDN1 gene on ischemic atherothrombotic stroke characteristics.. Materials and methods: Venous blood of 170 patients with ischemic atherothrombotic stroke (IAS) and 124 patients without cerebrovascular pathology, who made up the control group, used for the study. Lys198Asn (rs5370) polymorphism of the EDN1 gene was determined by the polymerase chain reaction method followed by restriction fragment length analysis. Statistical analysis was performed using SPSS-17.0. The values of Р < 0.05 were considered reliable.. Results: An association between the Lys198Asn polymorphism of the EDN1 gene and the IAS development was detected. For Asn/Asn genotype carriers, the risk of IAS developing is 4 times higher than that of homozygotes for the major allele. The association of this polymorphism with the arterial pool, whose atherothrombotic changes lead to the development of IAS, was found in individuals with BMI < 25 kg/m2. Lys198Asn polymorphism also affects the severity of IAS in persons with hypertension and non-smokers.. Conclusion: The Lys198Asn polymorphism of the EDN1 gene influences some characteristics of ischemic stroke.

Topics: Alleles; Endothelin-1; Genotype; Humans; Polymorphism, Single Nucleotide; Stroke

Endothelin-1 (ET-1) is synthesized and upregulated in astrocytes under stroke. We previously demonstrated that transgenic mice over-expressing astrocytic ET-1 (GET-1) displayed more severe neurological deficits characterized by a larger infarct after transient middle cerebral artery occlusion (tMCAO). ET-1 is a known vasoconstrictor, mitogenic, and a survival factor. However, it is unclear whether the observed severe brain damage in GET-1 mice post stroke is due to ET-1 dysregulation of neurogenesis by altering the stem cell niche.. Non-transgenic (Ntg) and GET-1 mice were subjected to tMCAO with 1 h occlusion followed by long-term reperfusion (from day 1 to day 28). Neurological function was assessed using a four-point scale method. Infarct area and volume were determined by 2,3,5-triphenyltetra-zolium chloride staining. Neural stem cell (NSC) proliferation and migration in subventricular zone (SVZ) were evaluated by immunofluorescence double labeling of bromodeoxyuridine (BrdU), Ki67 and Sox2, Nestin, and Doublecortin (DCX). NSC differentiation in SVZ was evaluated using the following immunofluorescence double immunostaining: BrdU and neuron-specific nuclear protein (NeuN), BrdU and glial fibrillary acidic protein (GFAP). Phospho-Stat3 (p-Stat3) expression detected by Western-blot and immunofluorescence staining.. GET-1 mice displayed a more severe neurological deficit and larger infarct area after tMCAO injury. There was a significant increase of BrdU-labeled progenitor cell proliferation, which co-expressed with GFAP, at SVZ in the ipsilateral side of the GET-1 brain at 28 days after tMCAO. p-Stat3 expression was increased in both Ntg and GET-1 mice in the ischemia brain at 7 days after tMCAO. p-Stat3 expression was significantly upregulated in the ipsilateral side in the GET-1 brain than that in the Ntg brain at 7 days after tMCAO. Furthermore, GET-1 mice treated with AG490 (a JAK2/Stat3 inhibitor) sh owed a significant reduction in neurological deficit along with reduced infarct area and dwarfed astrocytic differentiation in the ipsilateral brain after tMCAO.. The data indicate that astrocytic endothelin-1 overexpression promotes progenitor stem cell proliferation and astr ocytic differentiation via the Jak2/Stat3 pathway.

Topics: Animals; Astrocytes; Cell Differentiation; Cell Proliferation; Doublecortin Protein; Endothelin-1; Janus Kinase 2; Male; Mice; Mice, Transgenic; Neural Stem Cells; Neurogenesis; Signal Transduction; STAT3 Transcription Factor; Stroke; Up-Regulation

The sole FDA-approved drug treatment for ischemic stroke is tissue-type plasminogen activator (tPA). However, upregulation of JNK mitogen-activated protein kinase (MAPK) and endothelin 1 (ET-1) by tPA after stroke contributes to impaired cerebrovascular autoregulation. Wild-type (wt) tPA can bind to the lipoprotein-related receptor (LRP), which mediates vasodilation, or NMDA receptors (NMDA-Rs), exacerbating vasoconstriction. Elevations in IL-6, a marker of inflammation that accompanies stroke, are reported to be an adverse prognostic factor. We hypothesized that IL-6 released into CSF after stroke by wt-tPA through activation of NMDA-Rs and upregulation of ET-1 and JNK contribute to impairment of cerebrovascular autoregulation and increased histopathology. Results show that IL-6 was increased post stroke in pigs, which was increased further by wt-tPA. Co-administration of the IL-6 antagonist LMT-28 with wt-tPA prevented impairment of cerebrovascular autoregulation and necrosis of hippocampal cells. wt-tPA co-administered with the JNK inhibitor SP 600125 and the ET-1 antagonist BQ 123 blocked stroke-induced elevation of IL-6. Co-administration of LMT-28 with wt-tPA blocked the augmentation of JNK and ET-1 post stroke. In conclusion, IL-6 released after stroke, which is enhanced by wt-tPA through activation of NMDA-Rs and upregulation of ET-1 and JNK, impairs cerebrovascular autoregulation and increases histopathology. Strategies that promote fibrinolysis while limiting activation of NMDA-Rs and upregulation of IL-6 may improve the benefit/risk ratio compared to wt-tPA in treatment of stroke.

Topics: Animals; Anthracenes; Cerebral Cortex; Disease Models, Animal; Endothelin-1; Hippocampus; Homeostasis; Interleukin-6; Necrosis; Oxazolidinones; Random Allocation; Receptors, N-Methyl-D-Aspartate; Signal Transduction; Stroke; Swine; Tissue Plasminogen Activator; Up-Regulation

Cerebral microdialysis can be used to detect mitochondrial dysfunction, a potential target of neuroprotective treatment. Cyclosporin A (CsA) is a mitochondrial stabiliser that in a recent clinical stroke trial showed protective potential in patients with successful recanalisation. To investigate specific metabolic effects of CsA during reperfusion, and hypothesising that microdialysis values can be used as a proxy outcome measure, we assessed the temporal patterns of cerebral energy substrates related to oxidative metabolism in a model of transient focal ischaemia. Transient ischaemia was induced by intracerebral microinjection of endothelin-1 (150 pmol/15 µL) through stereotaxically implanted guide cannulas in awake, freely moving rats. This was immediately followed by an intravenous injection of CsA (NeuroSTAT; 15 mg/kg) or placebo solution during continuous microdialysis monitoring. After reperfusion, the lactate/pyruvate ratio (LPR) was significantly lower in the CsA group vs placebo (n = 17, 60.6 ± 24.3%, p = 0.013). Total and striatal infarct volumes (mm

Topics: Animals; Brain Ischemia; Cell Respiration; Cyclosporine; Endothelin-1; Infarction; Ischemic Attack, Transient; Male; Microdialysis; Mitochondria; Oxidative Stress; Rats; Rats, Sprague-Dawley; Stroke

We have previously demonstrated that R18 and its d-enantiomer, R18D, are neuroprotective at 24 hours following intraluminal filament occlusion of the middle cerebral artery (MCAO) in the rat. This study examined R18 and R18D effectiveness in improving functional outcomes at up to 56 days poststroke following endothelin-1-induced MCAO. Peptides were administered intravenously at doses of 100, 300, or 1000 nmol/kg, 60 minutes after MCAO. Functional recovery poststroke was assessed using multiple forelimb placing tests and horizontal ladder test, and NA-1 (TAT-NR2B9c), a neuroprotective currently in phase 3 clinical stroke trials, was used as a benchmark. The study demonstrated that R18 (300 and 1000 nmol/kg) was the most effective peptide in improving functional outcomes, followed by R18D (300 and 1000 nmol/kg), and NA-1 (300 and 100 nmol/kg). Furthermore, R18 at doses of 300 and 1000 nmol/kg was the most effective agent in restoring pre-stroke body weight, while R18 and R18D at doses of 300 and 1000 nmol/kg, but not NA-1 also significantly reduced the number of animals requiring hand feeding 48 hours after stroke. This study confirms that R18 and R18D are effective in improving long-term functional outcomes after stroke, and suggests that R18 may be more effective than NA-1.

Topics: Animals; Endothelin-1; Infusions, Intravenous; Intracellular Signaling Peptides and Proteins; Male; Peptides; Rats; Rats, Sprague-Dawley; Recovery of Function; Stroke; Treatment Outcome

Tissue-type plasminogen activator (tPA) is neurotoxic and exacerbates uncoupling of cerebral blood flow (CBF) and metabolism after stroke, yet it remains the sole FDA-approved drug for treatment of ischemic stroke. Upregulation of c-Jun-terminal kinase (JNK) after stroke contributes to tPA-mediated impairment of autoregulation, but the role of endothelin-1 (ET-1) is unknown. Based on the Glasgow Coma Scale, impaired autoregulation is linked to adverse outcomes after TBI, but correlation with hippocampal histopathology after stroke has not been established. We propose that given after stroke, tPA activates N-Methyl-D-Aspartate receptors (NMDA-Rs) and upregulates ET-1 in a JNK dependent manner, imparing autoregulation and leading to histopathology. After stroke, CBF was reduced in the hippocampus and reduced further during hypotension, which did not occur in hypotensive sham pigs, indicating impairment of autoregulation. Autoregulation and necrosis of hippocampal CA1 and CA3 neurons were further impaired by tPA, but were preserved by the ET-1 antagonist BQ 123 and tPA-A,

Topics: Animals; Cerebrovascular Circulation; Endothelin-1; Female; Hippocampus; Homeostasis; Male; Necrosis; Neurons; Stroke; Swine; Tissue Plasminogen Activator; Up-Regulation

Stroke patients often suffer from delayed disturbances of mood and cognition. In rodents, the prefrontal cortex (PFC) is involved in both higher order cognition and emotion. Our objective was to determine if bilateral focal ischaemic lesions restricted to the medial prefrontal cortex (mPFC) could be used to model post-stroke anxiety and/or cognitive deficits.. Groups of adult male Sprague-Dawley rats (n=9) received bilateral injections of either endothelin-1 (ET-1) (400 pmol) or vehicle (artificial cerebrospinal fluid) into the mPFC and were tested at various times using both a test of temporal order memory and in an elevated plus maze. Lesions were verified histologically.. ET-1 lesioned rats had reduced mobility on post-surgery day 8 that had resolved by day 29 at which time they spent significantly more time in the closed arm of the plus maze CONCLUSION: We conclude that ischaemic lesions localised to the mPFC can be used to model post-stroke anxiety in rats.

Topics: Animals; Anxiety; Behavior, Animal; Brain Ischemia; Cognitive Dysfunction; Disease Models, Animal; Endothelin-1; Male; Maze Learning; Memory; Prefrontal Cortex; Rats; Rats, Sprague-Dawley; Stroke

To better understand the effects of a diet high in fat, sugar, and sodium on cerebrovascular function, Sprague Dawley rats were chronically exposed to a Cafeteria diet. Resting cerebral perfusion and cerebrovascular reactivity was quantified using continuous arterial spin labeling (CASL) magnetic resonance imaging (MRI). In addition, structural changes to the cerebrovasculature and susceptibility to ischemic lesion were examined. Compared to control animals fed standard chow (SD), Cafeteria diet (CAF) rats exhibited increased resting brain perfusion in the hippocampus and reduced cerebrovascular reactivity in response to 10% inspired CO

Topics: Animals; Blood-Brain Barrier; Cerebral Cortex; Cerebrovascular Circulation; Diet, Western; Disease Models, Animal; Endothelin-1; Hemodynamics; Hippocampus; Male; Metabolic Syndrome; Random Allocation; Rats, Sprague-Dawley; Stroke

Stroke is a leading cause of death worldwide and inflicts serious long-term damage and disability. The vasoconstrictor Endothelin-1, presenting long-term neurological deficits associated with excitotoxicity and oxidative stress is being increasingly used to induce focal ischemic injury as a model of stroke. A DJ-1 based peptide named ND-13 was shown to protect against glutamate toxicity, neurotoxic insults and oxidative stress in various animal models. Here we focus on the benefits of treatment with ND-13 on the functional outcome of focal ischemic injury. Wild type C57BL/6 mice treated with ND-13, after ischemic induction in this model, showed significant improvement in motor function, including improved body balance and motor coordination, and decreased motor asymmetry. We found that DJ-1 knockout mice are more sensitive to Endothelin-1 ischemic insult than wild type mice, contributing thereby additional evidence to the widely reported relevance of DJ-1 in neuroprotection. Furthermore, treatment of DJ-1 knockout mice with ND-13, following Endothelin-1 induced ischemia, resulted in significant improvement in motor functions, suggesting that ND-13 provides compensation for DJ-1 deficits. These preliminary results demonstrate a possible basis for clinical application of the ND-13 peptide to enhance neuroprotection in stroke patients.

Topics: Animals; Brain Ischemia; Cell-Penetrating Peptides; Disease Models, Animal; Endothelin-1; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Neuroprotective Agents; Oxidative Stress; Peptide Fragments; Protein Deglycase DJ-1; Recovery of Function; Stroke; Vasoconstrictor Agents

What is the central question of this study? Angiotensin-(1-7) decreases cerebral infarct volume and improves neurological function when delivered centrally before and during ischaemic stroke. Here, we assessed the neuroprotective effects of angiotensin-(1-7) when delivered orally post-stroke. What is the main finding and its importance? We show that oral delivery of angiotensin-(1-7) attenuates cerebral damage induced by middle cerebral artery occlusion in rats, without affecting blood pressure or cerebral blood flow. Importantly, these treatments begin post-stroke at times coincident with the treatment window for tissue plasminogen activator, providing supporting evidence for clinical translation of this new therapeutic strategy.. As a target for stroke therapies, the angiotensin-converting enzyme 2-angiotensin-(1-7)-Mas [ACE2/Ang-(1-7)/Mas] axis of the renin-angiotensin system can be activated chronically to induce neuroprotective effects, in opposition to the deleterious effects of angiotensin II via its type 1 receptor. However, more clinically relevant treatment protocols with Ang-(1-7) that involve its systemic administration beginning after the onset of ischaemia have not been tested. In this study, we tested systemic post-stroke treatments using a molecule where Ang-(1-7) is included within hydroxypropyl-β-cyclodextrin [HPβCD-Ang-(1-7)] as an orally bioavailable treatment. In three separate protocols, HPβCD-Ang-(1-7) was administered orally to Sprague-Dawley rats after induction of ischaemic stroke by endothelin-1-induced middle cerebral artery occlusion: (i) to assess its effects on cerebral damage and behavioural deficits; (ii) to determine its effects on cardiovascular parameters; and (iii) to determine whether it altered cerebral blood flow. The results indicate that post-stroke oral administration of HPβCD-Ang-(1-7) resulted in 25% reductions in cerebral infarct volumes and improvement in neurological functions (P < 0.05), without inducing any alterations in blood pressure, heart rate or cerebral blood flow. In conclusion, Ang-(1-7) treatment using an oral formulation after the onset of ischaemia induces significant neuroprotection in stroke and might represent a viable approach for taking advantage of the protective ACE2/Ang-(1-7)/Mas axis in this disease.

Topics: 2-Hydroxypropyl-beta-cyclodextrin; Angiotensin I; Animals; Blood Pressure; Cerebrovascular Circulation; Endothelin-1; Infarction, Middle Cerebral Artery; Male; Neuroprotection; Neuroprotective Agents; Peptide Fragments; Rats; Rats, Sprague-Dawley; Renin-Angiotensin System; Stroke

Reach training in concert with environmental enrichment provides functional benefits after experimental stroke in rats. The present study extended these findings by assessing whether intensive task-specific reach training or enrichment initiated alone would provide similar functional benefit. Additionally, we investigated whether the 70% recovery rule, or a combined model of initial poststroke impairment, cortical infarct volume, and rehabilitation intensity, could predict recovery in the single-pellet task, as previously found for the Montoya staircase.. Rats were trained on single-pellet reaching before middle cerebral artery occlusion via intracerebral injection of ET-1 (endothelin-1). There were 4 experimental groups: stroke+enrichment, stroke+reaching, stroke+enrichment+reaching, and sham+enrichment+reaching. Reaching rehabilitation utilized a modified Whishaw box that encouraged impaired forelimb reaching for 6 hours per day, 5 days per week, for 4 weeks. All treatment paradigms began 7 days after ischemia with weekly assessment on the single-pellet task during rehabilitation and again 4 weeks after rehabilitation concluded.. Rats exposed to the combination of enrichment and reaching showed the greatest improvement in pellet retrieval and comparable performance to shams after 3 weeks of treatment, whereas those groups that received a monotherapy remained significantly impaired at all time points. Initial impairment alone did not significantly predict recovery in single-pellet as the 70% rule would suggest; however, a combined model of cortical infarct volume and rehabilitation intensity predicted change in pellet retrieval on the single-pellet task with the same accuracy as previously shown with the staircase, demonstrating the generalizability of this model across reaching tasks.. Task-specific reach training and environmental enrichment have synergistic effects in rats that persist long after rehabilitation ends, and this recovery is predicted by infarct volume and rehabilitation intensity.

Topics: Animals; Brain Ischemia; Disease Models, Animal; Endothelin-1; Infarction, Middle Cerebral Artery; Male; Motor Skills; Rats, Sprague-Dawley; Recovery of Function; Stroke; Stroke Rehabilitation

Topics: Animals; Astrocytes; Behavior, Animal; Endothelin-1; Glucose Transporter Type 1; Hindlimb Suspension; Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit; Infarction, Middle Cerebral Artery; Male; Neurons; Neuroprotection; Psychomotor Performance; Rats; Rats, Sprague-Dawley; Recognition, Psychology; Stroke

There are a lot of convincing evidences about the involvement of endothelin pathway proteins in the pathogenesis of atherosclerosis and its fatal complications. In this study, the analysis of a possible association between

Topics: Aged; Brain Ischemia; Carotid Artery Diseases; Endothelin-1; Female; Humans; Male; Middle Aged; Polymorphism, Single Nucleotide; Receptor, Endothelin A; Stroke; Ukraine

The association of poor outcome and mortality with low levels of hemoglobin (Hb) and hematocrit (HcT) in patients admitted after acute Ischemic Stroke (IS) was recently demonstrated. The mechanisms behind this still remain unclear. Our study aims to find out whether mRNA expressions and plasma concentrations of endothelin-1 (ET-l), endothelin-2 (ET-2) and endothelin-3 (ET-3) remain different in IS sufferers with low HcT and Hb levels in comparison with those whose HcT i Hb levels during a severe IS episode remain within the norm. The study included 60 patients treated consecutively for first-time IS. The assessment of mRNA gene expression and plasma concentration of ET-1, ET-2, ET-3 was conducted in the first, third and seventh day following the onset of stroke using qRT-PCR method and ELISA tests. We demonstrated that patients whose initial HcT and Hb levels were below the norm presented a deeper neurologic deficit on 1, 3 and 7 day following stroke with noticeable improvement no earlier than between day 3 and 7. We also found a negative correlation between the initial HcT and Hb and concentration of plasma ET-1 on the same days. The patients whose HcT and Hb levels were within normal limits showed a significant improvement in their neurologic condition on each consecutive day of the observation. Reduced levels of Hb and HcT combined with an increased plasma concentration of vasoconstrictive endothelin-1 are strongly associated with poor outcome and high mortality in acute ischemic stroke.

Topics: Aged; Aged, 80 and over; Blood Pressure; Brain Ischemia; C-Reactive Protein; Calcitonin; Endothelin-1; Female; Hematocrit; Hemoglobins; Humans; Male; Middle Aged; RNA, Messenger; Stroke; Tomography Scanners, X-Ray Computed; Vasoconstriction

Research into stroke is driven by frustration over the limited available therapeutics. Targeting a single aspect of this multifactorial disease contributes to the therapeutic boundaries. To overcome this, we devised a novel multifactorial-cocktail treatment, using lentiviruses encoding excitatory amino acid transporter 2 (EAAT2(, glutamate dehydrogenase 2 (GDH2), and nuclear factor E2-related factor 2 (Nrf2) genes, that acts synergistically to address the effected excito-oxidative axis. Here, we used the vasoconstrictor endothelin-1 (ET-1) to induce focal ischemic injury in mice by direct injection into the striatum. Mice treated with the mixture of these three genes show significant improvement in body balance, motor coordination, and decreased motor asymmetry compared to each gene separately. These results demonstrate that overexpression of the combined EAAT2, GDH2, and NRF2 genes can provide neuroprotection after ischemic injury.

Topics: Animals; Brain Ischemia; Endothelin-1; Excitatory Amino Acid Transporter 2; Genetic Therapy; Glutamate Dehydrogenase; Male; Mice; Mice, Inbred C57BL; NF-E2-Related Factor 2; Stroke

Endothelin-1 (ET-1), a vasoconstrictor, has recently been used to induce focal ischemia in rodents and marmoset monkeys. The rhesus monkey, however, has numerous advantages to the rodent and marmoset that make it a superior and irreplaceable animal model for studying stroke in the brain. In the present study, after mapping the preferred hand representation in two healthy male monkeys with intracortical micro-stimulation, ET-1 was microinjected into the contralateral motor cortex (M1) to its preferred hand. The monkeys had been trained in three manual dexterity tasks before the microinjection and were tested for these tasks following the ET-1 injection. Brain Magnetic Resonance Imaging scans were performed 1, 7, 14 and 28 days post ischemia. It was found that ET-1 impaired the manual dexterity of the monkeys in the vertical slot and rotating Brinkman board tasks 3-8 days after the injection. Brain imaging found that severe edema was present 7 days after the focal ischemia. This data suggest that ET-1 can induce transient ischemic stroke in rhesus monkey and that ET-1 induced focal ischemia in non-human primates is a potential model to study the mechanism of stroke and brain repair after stroke.

Topics: Animals; Brain; Disease Models, Animal; Endothelin-1; Ischemic Attack, Transient; Macaca mulatta; Magnetic Resonance Imaging; Male; Motor Activity; Psychomotor Performance; Stroke; Vasoconstrictor Agents

Racemic l-3-n-butylphthalide (dl-NBP), is able to achieve a functional recovery in animal models of cerebral ischemia, vascular dementia, and Alzheimer's disease. In this study, we investigated the effect of dl-NBP on axonal growth, neurogenesis and behavioral performances in rats with cerebral ischemia.. Focal cerebral ischemia in rats was produced by intracerebral injection of endothelin-1. Starting from postoperative day 7, the experimental rats were administered 70mg/kg dl-NBP by oral gavage for two weeks. Biotinylated dextran amine (BDA) was injected into the contralateral sensorimotor cortex on day 14 after ischemia to trace the sprouting of corticospinal tract (CST) fibers into the denervated cervical spinal cord. The expressions of Nogo-A, Nogo-R, Rho-A, and ROCK in the perilesional cortex, the expressions of BDA, PSD-95, and vGlut1 in the denervated spinal cord, 5-bromo-20-deoxyuridine (BrdU)/DCX-positive cells in the subventricular zone (SVZ) of the injured hemisphere were detected by immunofluorescence. The rats' behavioral abilities were measured on postoperative days 30-32 in the beam-walking, cylinder and sticky label tests.. dl-NBP treatment significantly increased the number and length of crossing CST fibers, enhanced significantly the expression levels of synapse-associated proteins including PSD95 and VGlut-1 in the denervated cervical spinal cord, elevated the number of BrdU+/DCX+ cells in SVZ, and reduced markedly those of Rho-A+, ROCK+, Nogo-A+ and Nogo-R+ cells in perilesional cortex. In addition, dl-NBP improved the behavioral performance of the ischemic rats.. dl-NBP enhanced the behavioral recovery after cerebral ischemia in rats, possibly by increasing axonal growth and neurogenesis.

Topics: Animals; Benzofurans; Biotin; Brain Infarction; Dextrans; Disease Models, Animal; Disks Large Homolog 4 Protein; Doublecortin Protein; Endothelin-1; Male; Motor Activity; Neuronal Plasticity; Nogo Proteins; Nogo Receptor 1; Platelet Aggregation Inhibitors; Psychomotor Performance; Rats; Rats, Wistar; Recovery of Function; Signal Transduction; Stroke; Vesicular Glutamate Transport Protein 1

Maintenance of white matter integrity in health and disease is critical for a variety of neural functions. Ischemic stroke in the white matter frequently results in degeneration of oligodendrocytes (OLs) and myelin. Previously, we found that toll-like receptor 2 (TLR2) expressed in OLs provides cell-autonomous protective effects on ischemic OL death and demyelination in white matter stroke. Here, we identified high-mobility group box-1 (HMGB1) as an endogenous TLR2 ligand that promotes survival of OLs under ischemic stress. HMGB1 rapidly accumulated in the culture medium of OLs exposed to oxygen-glucose deprivation (OGD). This conditioned medium exhibited a protective activity against ischemic OL death that was completely abolished by immunodepletion of HMGB1. Knockdown of HMGB1 or application of glycyrrhizin, a specific HMGB1 inhibitor, aggravated OGD-induced OL death, and recombinant HMGB1 application reduced the extent of OL death in a TLR2-dependent manner. We confirmed that cytosolic translocation of HMGB1 and activation of TLR2-mediated signaling pathways occurred in a focal white matter stroke model induced by endothelin-1 injection. Animals with glycyrrhizin coinjection showed an expansion of the demyelinating lesion in a TLR2-dependent manner, accompanied by aggravation of sensorimotor behavioral deficits. These results indicate that HMGB1/TLR2 activates an autocrine trophic signaling pathways in OLs and myelin to maintain structural and functional integrity of the white matter under ischemic conditions.

Topics: Animals; Brain Ischemia; Cells, Cultured; Demyelinating Diseases; Endothelin-1; HMGB1 Protein; Male; Mice; Mice, Inbred C57BL; Myelin Sheath; Oligodendroglia; Signal Transduction; Stroke; Toll-Like Receptor 2; White Matter

Stroke is the leading cause of adult disability worldwide. The absence of more effective interventions in the chronic stage-that most patients stand to benefit from-reflects uncertainty surrounding mechanisms that govern recovery. The present work investigated the effects of a novel treatment (selective cyclooxygenase-1, COX-1, inhibition) in a model of focal ischemia.. FR122047 (COX-1 inhibitor) was given beginning 7 days following stroke (cortical microinjection of endothelin-1) in 23 adult male rats. Longitudinal continuous-arterial-spin-labeling was performed prior to treatment (7 days), and repeated following treatment (21 days) on a 7T magnetic resonance imaging (MRI) system to estimate resting perfusion and reactivity to hypercapnia. These in vivo measurements were buttressed by immunohistochemistry.. These findings shed light on the role of COX-1 in chronic ischemic injury and suggest that delayed selective COX-1 inhibition exerts multiple beneficial effects on the neurogliovascular unit.. 1 Technical Efficacy: Stage 4 J. MAGN. RESON. IMAGING 2017;46:505-517.

Topics: Animals; Cyclooxygenase 1; Cyclooxygenase Inhibitors; Disease Models, Animal; Endothelin-1; Ischemia; Macrophages; Magnetic Resonance Imaging; Male; Membrane Proteins; Microglia; Neuroglia; Neurons; Perfusion; Piperazines; Rats; Rats, Sprague-Dawley; Spin Labels; Stroke; Thiazoles

Brain plasticity following focal cerebral ischaemia has been observed in both stroke survivors and in preclinical models of stroke. Endogenous neurovascular adaptation is at present incompletely understood yet its potentiation may improve long-term functional outcome. We employed longitudinal MRI, intracranial array electrophysiology, Montoya Staircase testing, and immunofluorescence to examine function of brain vessels, neurons, and glia in addition to forelimb skilled reaching during the subacute stage of ischemic injury progression. Focal ischemic stroke (~100mm

Topics: Animals; Brain; Brain Ischemia; Brain Waves; Encephalitis; Endothelin-1; Hypercapnia; Magnetic Resonance Imaging; Male; Motor Skills; Neuroglia; Neurons; Physical Stimulation; Rats, Sprague-Dawley; Recovery of Function; Sensorimotor Cortex; Somatosensory Cortex; Stroke; Touch Perception; Vascular Remodeling

Hypertension is one of the co-morbid conditions for stroke and profoundly increases its incidence. Angiotensin II (AngII) is shown to be at the center stage in driving the renin angiotensin system via activation of angiotensin 1 receptor (AT1R). This makes the AT1R gene one of the candidates whose differential regulation leads to the predisposition to disorders associated with hypertension. A haplotype block of four SNPs is represented primarily by haplotype-I, or Hap-I (TTAA), and haplotype-II, or Hap-II (AGCG), in the promoter of human AT1R (hAT1R) gene. To better understand the physiological role of these haplotypes, transgenic (TG) mice containing Hap-I and Hap-II of the hAT1R gene in a 166-kb bacterial artificial chromosome (BAC) were generated. Mice received injection of endothelin-1 (1 mg/ml) directly in to the striatum and were evaluated for neurologic deficit scores and sacrificed for analysis of infarct volume and mRNA levels of various proteins. Mice containing Hap-I suffered from significantly higher neurological deficits and larger brain infarcts than Hap II. Similarly, the molecular analysis of oxidant and inflammatory markers in brains of mice showed a significant increase (p < 0.05) in NOX-1 (2.3-fold), CRP (4.3-fold), and IL6 (1.9-fold) and a corresponding reduced expression of antioxidants SOD (60%) and HO1 (55%) in Hap-I mice as compared to Hap-II mice. These results suggest that increased expression of hAT1R rendered Hap-I TG mice susceptible to stroke-related pathology, possibly due to increased level of brain inflammatory and oxidative stress markers and a suppressed antioxidant defense system.

Topics: Animals; Corpus Striatum; Endothelin-1; Haplotypes; Humans; Interleukin-6; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; NADH, NADPH Oxidoreductases; NADPH Oxidase 1; Nerve Tissue Proteins; Oxidative Stress; Receptor, Angiotensin, Type 1; Recombinant Fusion Proteins; Stroke; Superoxide Dismutase-1

Glucose-dependent insulinotropic polypeptide (GIP) is an incretin hormone with extrapancreatic effects beyond glycemic control. Here we demonstrate unexpected effects of GIP signaling in the vasculature. GIP induces the expression of the proatherogenic cytokine osteopontin (OPN) in mouse arteries via local release of endothelin-1 and activation of CREB. Infusion of GIP increases plasma OPN concentrations in healthy individuals. Plasma endothelin-1 and OPN concentrations are positively correlated in patients with critical limb ischemia. Fasting GIP concentrations are higher in individuals with a history of cardiovascular disease (myocardial infarction, stroke) when compared with control subjects. GIP receptor (GIPR) and OPN mRNA levels are higher in carotid endarterectomies from patients with symptoms (stroke, transient ischemic attacks, amaurosis fugax) than in asymptomatic patients, and expression associates with parameters that are characteristic of unstable and inflammatory plaques (increased lipid accumulation, macrophage infiltration, and reduced smooth muscle cell content). While GIPR expression is predominantly endothelial in healthy arteries from humans, mice, rats, and pigs, remarkable upregulation is observed in endothelial and smooth muscle cells upon culture conditions, yielding a "vascular disease-like" phenotype. Moreover, the common variant rs10423928 in the GIPR gene is associated with increased risk of stroke in patients with type 2 diabetes.

Topics: Aged; Aged, 80 and over; Animals; Aorta; Blotting, Western; Cardiovascular Diseases; Carotid Arteries; Case-Control Studies; Coronary Vessels; Cyclic AMP Response Element-Binding Protein; Diabetes Mellitus, Type 2; Endothelial Cells; Endothelin-1; Enzyme-Linked Immunosorbent Assay; Female; Fluorescent Antibody Technique; Gastric Inhibitory Polypeptide; Humans; Immunohistochemistry; Male; Mice; Mice, Knockout; Microscopy, Confocal; Microvessels; Middle Aged; Myocytes, Smooth Muscle; Osteopontin; Peripheral Arterial Disease; Plaque, Atherosclerotic; Polymorphism, Single Nucleotide; Rats; Rats, Inbred WKY; Real-Time Polymerase Chain Reaction; Receptors, Gastrointestinal Hormone; RNA, Messenger; Stroke; Sus scrofa; Swine

There is an urgent need for a therapy that reverses disability after stroke when initiated in a time frame suitable for the majority of new victims. We show here that intramuscular delivery of neurotrophin-3 (NT3, encoded by NTF3) can induce sensorimotor recovery when treatment is initiated 24 h after stroke. Specifically, in two randomized, blinded preclinical trials, we show improved sensory and locomotor function in adult (6 months) and elderly (18 months) rats treated 24 h following cortical ischaemic stroke with human NT3 delivered using a clinically approved serotype of adeno-associated viral vector (AAV1). Importantly, AAV1-hNT3 was given in a clinically-feasible timeframe using a straightforward, targeted route (injections into disabled forelimb muscles). Magnetic resonance imaging and histology showed that recovery was not due to neuroprotection, as expected given the delayed treatment. Rather, treatment caused corticospinal axons from the less affected hemisphere to sprout in the spinal cord. This treatment is the first gene therapy that reverses disability after stroke when administered intramuscularly in an elderly body. Importantly, phase I and II clinical trials by others show that repeated, peripherally administered high doses of recombinant NT3 are safe and well tolerated in humans with other conditions. This paves the way for NT3 as a therapy for stroke.

Topics: Adenoviridae; Age Factors; Animals; Endothelin-1; Female; Genetic Vectors; Humans; Injections, Intramuscular; Locomotion; Magnetic Resonance Imaging; Microinjections; Muscle, Skeletal; Neuroimaging; Neurotrophin 3; Pyramidal Tracts; Rats; Recovery of Function; Spinal Cord; Stroke; Time Factors

Cortical injections of the vasoconstrictor endothelin-1 (ET1) have widely been used to induce focal circumscribed ischemic lesions in the motor cortex of rodents in the context of stroke recovery studies. In order to apply this model correctly, it is essential to understand the time course of regional flow changes and of the development of penumbra and infarction.. Multitracer micro-PET of ET1 focal ischemia in rats was performed using [11C]-flumazenil ([11C]FMZ) as a flow- and viability tracer and [18F]-fluoromisonidazole ([18F]FMISO) as hypoxia marker in order to characterize the physiological time-course of this model. Nine adult Sprague-Dawley rats received stereotaxic injections of ET1 into the right primary motor cortex, 3 served as controls. PET imaging was started 2, 3 and 20 h after the last ET1 injection. Histology was obtained at the end of the scans. Standardized uptake value ratios reflecting cerebral blood flow (CBF), [11C]FMZ-binding and [18F]FMISO-retention were calculated for the region of hypoperfusion and the normoperfused cortex.. CBF in the hypoperfused cortex was significantly reduced (p < 0.01) at 5 h (0.58 ± 0.025), 6 h (0.54 ± 0.043) and 23 h (0.66 ± 0.024) compared to controls (1.00 ± 0.011) and moderately reduced (p < 0.05) in the remainder of the affected hemisphere at 5 h (0.93 ± 0.036). [11C]FMZ-binding was within the control range at all time points. Significant [18F]FMISO-retention (1.16 ± 0.091, p < 0.05) was observed only after 6 h in the ischemic core that later turned into infarct.. ET1 injections yield reproducible, slowly developing ischemic lesions with constant levels of hypoperfusion. This multitracer micro-PET study suggests that the ET1 model is appropriate for inducing chronic circumscribed ischemic lesions but seems to be less suited for studying acute stroke pathophysiology.

Topics: Animals; Brain; Brain Ischemia; Cerebrovascular Circulation; Endothelin-1; Flumazenil; Infarction, Middle Cerebral Artery; Ischemia; Male; Models, Animal; Motor Cortex; Rats, Sprague-Dawley; Stroke

Neuromodulators, such as antidepressants, may contribute to neuroprotection by modulating growth factor expression to exert anti-inflammatory effects and to support neuronal plasticity after stroke. Our objective was to study whether early treatment with venlafaxine, a serotonin-norepinephrine reuptake inhibitor, modulates growth factor expression and positively contributes to reducing the volume of infarcted brain tissue resulting in increased functional recovery. We studied the expression of BDNF, FGF2 and TGF-β1 by examining their mRNA and protein levels and cellular distribution using quantitative confocal microscopy at 5 days after venlafaxine treatment in control and infarcted brains. Venlafaxine treatment did not change the expression of these growth factors in sham rats. In infarcted rats, BDNF mRNA and protein levels were reduced, while the mRNA and protein levels of FGF2 and TGF-β1 were increased. Venlafaxine treatment potentiated all of the changes that were induced by cortical stroke alone. In particular, increased levels of FGF2 and TGF-β1 were observed in astrocytes at 5 days after stroke induction, and these increases were correlated with decreased astrogliosis (measured by GFAP) and increased synaptophysin immunostaining at twenty-one days after stroke in venlafaxine-treated rats. Finally, we show that venlafaxine reduced infarct volume after stroke resulting in increased functional recovery, which was measured using ladder rung motor tests, at 21 days after stroke. Our results indicate that the early oral administration of venlafaxine positively contributes to neuroprotection during the acute and late events that follow stroke.

Topics: Animals; Antidepressive Agents; Astrocytes; Brain; Brain-Derived Neurotrophic Factor; Disease Models, Animal; Drug Evaluation, Preclinical; Endothelin-1; Fibroblast Growth Factor 2; Gliosis; Male; Neuroprotective Agents; Random Allocation; Rats, Sprague-Dawley; Recovery of Function; RNA, Messenger; Stroke; Transforming Growth Factor beta1; Venlafaxine Hydrochloride

BACKGROUND Ischemic stroke is widely recognized as a major health problem and social burden worldwide, and it usually leads to dementia. In this study, we aimed to better understand the pathogenesis in the development of dementia following ischemic stroke. MATERIAL AND METHODS We exploited miRNA database to search for the target for miR-125a and validated the found target using luciferase assay. Further, we performed real-time PCR and Western blot analysis to examine the expression of miR-125a and its target in the tissue samples. In addition, a polymorphism was genotyped and its association with post-stroke dementia was analyzed. RESULTS We identified enthothelin-1 (ET-1) as a target of miR-125a, and this relationship was validated using luciferase assay. Furthermore, transfection of miR-125a inhibitor substantially upregulated the expression of ET-1, while miR-125a and ET-1 siRNA caused downregulation of ET-1 in endothelial cells. In addition, we found that a polymorphism (rs12976445) interferes with the expression of miR-125a, which in turn caused an increase in the expression of ET-1 in human endothelial cells. Logistic regression analysis showed that rs12976445 is significantly associated with the risk of dementia after ischemic stroke. CONCLUSIONS Our study demonstrated the pathogenesis mechanism during the development of dementia after ischemic stroke by investigating the relationship between miR-125a and its target ET-1, promising a potential pathological solution for post-stroke dementia in the future.

Topics: 3' Untranslated Regions; Base Sequence; Brain Ischemia; Case-Control Studies; Dementia; Demography; Endothelin-1; Gene Expression Regulation; Genetic Predisposition to Disease; Human Umbilical Vein Endothelial Cells; Humans; Luciferases; MicroRNAs; Polymorphism, Single Nucleotide; RNA, Messenger; Stroke; Transfection

Several studies have used macaque monkeys with lesions induced in the primary motor cortex (M1) to investigate the recovery of motor function after brain damage. However, in human stroke patients, the severity and outcome of motor impairments depend on the degree of damage to the white matter, especially that in the posterior internal capsule, which carries corticospinal tracts. To bridge the gap between results obtained in M1-lesioned macaques and the development of clinical intervention strategies, we established a method of inducing focal infarcts at the posterior internal capsule of macaque monkeys by injecting endothelin-1 (ET-1), a vasoconstrictor peptide. The infarcts expanded between 3 days and 1 week after ET-1 injection. The infarct volume in each macaque was negatively correlated with precision grip performance 3 days and 1 week after injection, suggesting that the degree of infarct expansion may have been a cause of the impairment in hand movements during the early stage. Although the infarct volume decreased and gross movement improved, impairment of dexterous hand movements remained until the end of the behavioral and imaging experiments at 3 months after ET-1 injection. A decrease in the abundance of large neurons in M1, from which the descending motor tracts originate, was associated with this later-stage impairment. The present model is useful not only for studying neurological changes underlying deficits and recovery but also for testing therapeutic interventions after white matter infarcts in primates.

Topics: Animals; Disease Models, Animal; Endothelin-1; Female; Macaca; Male; Stroke

Post-stroke depression (PSD) is a common outcome following stroke that is associated with poor recovery. To develop a preclinical model of PSD, we targeted a key node of the depression-anxiety circuitry by inducing a unilateral ischemic lesion to the medial prefrontal cortex (mPFC) stroke. Microinjection of male C57/BL6 mice with endothelin-1 (ET-1, 1600 pmol) induced a small (1 mm(3)) stroke consistently localized within the left mPFC. Compared with sham control mice, the stroke mice displayed a robust behavioral phenotype in four validated tests of anxiety including the elevated plus maze, light-dark, open-field and novelty-suppressed feeding tests. In addition, the stroke mice displayed depression-like behaviors in both the forced swim and tail suspension test. In contrast, there was no effect on locomotor activity or sensorimotor function in the horizontal ladder, or cylinder and home cage activity tests, indicating a silent stroke due to the absence of motor abnormalities. When re-tested at 6 weeks post stroke, the stroke mice retained both anxiety and depression phenotypes. Surprisingly, at 6 weeks post stroke the lesion site was infiltrated by neurons, suggesting that the ET-1-induced neuronal loss in the mPFC was reversible over time, but was insufficient to promote behavioral recovery. In summary, unilateral ischemic lesion of the mPFC results in a pronounced and persistent anxiety and depression phenotype with no evident sensorimotor deficits. This precise lesion of the depression circuitry provides a reproducible model to study adaptive cellular changes and preclinical efficacy of novel interventions to alleviate PSD symptoms.

Topics: Animals; Anxiety; Behavior, Animal; Body Dysmorphic Disorders; Depression; Endothelin-1; Locomotion; Male; Mice; Neurons; Prefrontal Cortex; Stroke

Neuroblasts from the subventricular zone (SVZ) migrate to striatum following stroke, but most of them die in the ischaemic milieu and this can be related to exacerbated microglial activation. Here, we explored the effects of the non-steroidal anti-inflammatory indomethacin on microglial activation, neuronal preservation and neuroblast migration following experimental striatal stroke in adult rats. Animals were submitted to endothelin-1 (ET-1)-induced focal striatal ischaemia and were treated with indomethacin or sterile saline (i.p.) for 7 days, being perfused after 8 or 14 days. Immunohistochemistry was performed to assess neuronal loss (anti-NeuN), microglial activation (anti-Iba1, ED1) and migrating neuroblasts (anti-DCX) by counting NeuN, ED1 and DCX-positive cells in the ischaemic striatum or SVZ. Indomethacin treatment reduced microglia activation and the number of ED1+ cells in both 8 and 14 days post injury as compared with controls. There was an increase in the number of DCX+ cells in both SVZ and striatum at the same survival times. Moreover, there was a decrease in the number of NeuN+ cells in indomethacin-treated animals as compared with the control group at 8 days but not after 14 days post injury. Our results suggest that indomethacin treatment modulates microglia activation, contributing to increased neuroblast proliferation in the SVZ and migration to the ischaemic striatum following stroke.

Topics: Animals; Brain Ischemia; Cell Proliferation; Corpus Striatum; Doublecortin Protein; Endothelin-1; Humans; Indomethacin; Lateral Ventricles; Microglia; Neural Stem Cells; Neurogenesis; Neurons; Rats; Stroke

Stroke is a leading cause of death and neurological disability worldwide and striatal ischemic stroke is frequent in humans due to obstruction of middle cerebral artery. Several pathological events underlie damage progression and a comprehensive description of the pathological features following experimental stroke in both acute and chronic survival times is a necessary step for further functional studies. Here, we explored the patterns of microglial activation, astrocytosis, oligodendrocyte damage, myelin impairment, and Nogo-A immunoreactivity between 3 and 30 postlesion days (PLDs) after experimental striatal stroke in adult rats induced by microinjections of endothelin-1 (ET-1). The focal ischemia induced tissue loss concomitant with intense microglia activation between 3 and 14 PLDs (maximum at 7 PLDs), decreasing afterward. Astrocytosis was maximum around 7 PLDs. Oligodendrocyte damage and Nogo-A upregulation were higher at 3 PLDs. Myelin impairment was maximum between 7 and 14 PLDs. Nogo-A expression was higher in the first week in comparison to control. The results add important histopathological features of ET-1 induced stroke in subacute and chronic survival times. In addition, the establishment of the temporal evolution of these neuropathological events is an important step for future studies seeking suitable neuroprotective drugs targeting neuroinflammation and white matter damage.

Topics: Animals; Astrocytes; Brain; Brain Ischemia; Disease Models, Animal; Endothelin-1; Immunohistochemistry; Male; Microglia; Microscopy; Myelin Basic Protein; Nogo Proteins; Oligodendroglia; Rats; Rats, Wistar; Stroke; Up-Regulation; White Matter

Stroke is the third leading cause of death and permanent disability in the United States, often producing long-term cognitive impairments, which are not easily recapitulated in animal models. The goals of this study were to assess whether: (1) the endothelin-1 (ET-1) model of chronic stroke produced discernable cognitive deficits; (2) a spatial operant reversal task (SORT) would accurately measure memory deficits in this model; and (3) bone-marrow-derived mesenchymal stem cells (BMMSCs) could reduce any observed deficits.. Rats were given unilateral intracerebral injections of vehicle or ET-1, a stroke-inducing agent, near the middle cerebral artery. Seven days later, they were given intrastriatal injections of BMMSCs or vehicle, near the ischemic penumbra. The cognitive abilities of the rats were assessed on a novel SORT, which was designed to efficiently distinguish cognitive deficits from potential motoric confounds.. Rats given ET-1 had significantly more cognitive errors at six weeks post-stroke on the SORT, and that these deficits were attenuated by BMMSC transplants.. These findings indicate that: (1) the ET-1 model produces chronic cognitive deficits; (2) the SORT efficiently measures cognitive deficits that are not confounded by motoric impairment; and (3) BMMSCs may be a viable treatment for stroke-induced cognitive dysfunction.

Topics: Animals; Body Weight; Brain; Chronic Disease; Cognition Disorders; Conditioning, Operant; Disease Models, Animal; Endothelin-1; Female; Male; Mesenchymal Stem Cell Transplantation; Psychological Tests; Rats, Sprague-Dawley; Stroke; Treatment Outcome

Levels of cerebral amyloid, presumably β-amyloid (Abeta), toxicity and the incidence of cortical and subcortical ischemia increases with age. However, little is known about the severe pathological condition and dementia that occur as a result of the comorbid occurrence of this vascular risk factor and Abeta toxicity. Clinical studies have indicated that small ischemic lesions in the striatum are particularly important in generating dementia in combination with minor amyloid lesions. These cognitive deficits are highly likely to be caused by changes in the cortex. In this study, we examined the viability and morphological changes in microglial and neuronal cells, gap junction proteins (connexin43) and neuritic/axonal retraction (Fer Kinase) in the striatum and cerebral cortex using a comorbid rat model of striatal injections of endothelin-1 (ET1) and Abeta toxicity. The results demonstrated ventricular enlargement, striatal atrophy, substantial increases in β-amyloid, ramified microglia and increases in neuritic retraction in the combined models of stroke and Abeta toxicity. Changes in connexin43 occurred equally in both groups of Abeta-treated rats, with and without focal ischemia. Although previous behavioral tests demonstrated impairment in memory and learning, the visual discrimination radial maze task did not show significant difference, suggesting the cognitive impairment in these models is not related to damage to the dorsolateral striatum. These results suggest an insight into the relationship between cortical/striatal atrophy, pathology and functional impairment.

Topics: Amyloid beta-Peptides; Amyloidosis; Animals; Brain Ischemia; Cerebral Cortex; Comorbidity; Connexin 43; Corpus Striatum; Disease Models, Animal; Endothelin-1; Male; Maze Learning; Microglia; Nerve Degeneration; Neurites; Neurons; Protein-Tyrosine Kinases; Random Allocation; Rats, Wistar; Stroke; Visual Perception

The incidence of stroke in adulthood increases with advancing age, but there is little understanding of how poststroke treatment should be tailored by age.. The goal of this study was to determine if age and task specificity of rehabilitative training affect behavioral improvement and motor cortical organization after stroke.. Young and aged mice were trained to proficiency on the Pasta Matrix Reaching Task prior to lesion induction in primary motor cortex with endothelin-1. After a short recovery period, mice received 9 weeks of rehabilitative training on either the previously learned task (Pasta Matrix Reaching), a different reaching task (Tray Reaching), or no training. To determine the extent of relearning, mice were tested once weekly on the Pasta Matrix Reaching Task. Mice then underwent intracortical microstimulation mapping to resolve the remaining forelimb movement representations in perilesion motor cortex.. Although aged mice had significantly larger lesions compared with young mice, Pasta Matrix Reaching served as effective rehabilitative training for both age-groups. Young animals also showed improvement after Tray Reaching. Behavioral improvement in young mice was associated with an expansion of the rostral forelimb area ("premotor" cortex), but we failed to see reorganization in the aged brain, despite similar behavioral improvements.. Our results indicate that reorganization of motor cortex may be limited by either aging or greater tissue damage, but the capacity to improve motor function via task-specific rehabilitative training continues to be well maintained in aged animals.

Topics: Aging; Animals; Brain Ischemia; Disease Models, Animal; Electric Stimulation; Endothelin-1; Exercise Therapy; Male; Mice, Inbred C57BL; Motor Cortex; Motor Skills; Neuronal Plasticity; Recovery of Function; Stroke; Stroke Rehabilitation

Stroke, broadly subdivided into ischemic and hemorrhagic subtypes, is a serious health-care problem worldwide. Previous studies have suggested ischemic and hemorrhagic stroke could present different functional recovery patterns. However, little attention has been given to this neurobiological finding. Coincidently, astrocyte morphology could be related to improved sensorimotor recovery after skilled reaching training and modulated by physical exercise and environmental enrichment. Therefore, it is possible that astrocyte morphology might be linked to differential recovery patterns between ischemic and hemorrhagic stroke. Thus, we decided to compare long-term GFAP-positive astrocyte morphology after ischemic (IS, n=5), hemorrhagic (HS, n=5) and sham (S, n=5) stroke groups (induced by endothelin-1, collagenase type IV-S and salina, respectively). Our results showed ischemic and hemorrhagic stroke subtypes induced similar long-term GFAP-positive astrocyte plasticity (P>0.05) for all evaluated measures (regional and cellular optical density; astrocytic primary processes ramification and length; density of GFAP positive astrocytes) in perilesional sensorimotor cortex and striatum. These interesting negative results discourage similar studies focused on long-term plasticity of GFAP-positive astrocyte morphology and recovery comparison of stroke subtypes.

Topics: Animals; Astrocytes; Collagenases; Corpus Striatum; Endothelin-1; Glial Fibrillary Acidic Protein; Intracranial Hemorrhages; Ischemia; Prognosis; Rats; Rats, Wistar; Sensorimotor Cortex; Stroke

Constraint-induced movement therapy (CIMT) after stroke enhances not only functional reorganization but also structural plasticity of the brain in the adult rats. We examined whether forced limb-use which mimicked CIMT could influence ischemia-induced neurogenesis, apoptosis and behavioral recovery in the aged rats. Aged rats were divided into a sham group, an ischemia group, and an ischemia group with forced limb-use. Focal cerebral ischemia was induced by injection of endothelin-1. Forced limb-use began on post-stroke day 7 by fitting a plaster cast around the unimpaired upper limbs of rats for 3 weeks. Behavioral recovery was evaluated by tapered/ledged beam-walking test on postoperative day 32. The expression of doublecortin, neuronal nuclei, glial fibrillary acidic protein and Iba-1 were measured by single or double immunohistochemistry, and apoptosis was measured by TdT-mediated dUTP-biotin nick-end labeling (TUNEL) assay. The production of neuroblasts in the subventricular zone (SVZ) was significantly increased after stroke. Forced limb-use enhanced the proliferation of newborn neurons in the SVZ, as well as increased the long-term survival of newborn neurons. Furthermore, forced limb-use suppressed apoptosis and improved the motor functions after stroke in the aged rats. Forced limb-use exerted few effects on inflammation. Neither the number nor dendritic complexity of newborn granule cells in the hippocampus was affected by forced limb-use. Forced limb-use is effective in enhancing neurogenesis and behavioral recovery after stroke even in the aged rats.

Topics: Animals; Apoptosis; Brain Ischemia; Cell Proliferation; Disease Models, Animal; Doublecortin Protein; Endothelin-1; Lateral Ventricles; Locomotion; Male; Neurogenesis; Neurons; Physical Therapy Modalities; Rats; Rats, Sprague-Dawley; Restraint, Physical; Stroke; Stroke Rehabilitation

Sporadic Alzheimer's disease (AD) accounts for a high proportion of AD cases. Therefore, it is of importance to investigate other factors that contribute to the etiology and progression of AD. AD is characterized by decreased cholinergic tone, tau hyperphosphorylation and beta-amyloid (Aβ) accumulation. In addition to the hallmark pathology, other factors have been identified that increase the risk of AD, including stroke. This study examined the combined effects of beta-amyloid administration and unilateral stroke in an animal model of AD. Adult rats were given a sham surgery, bilateral intraventricular infusion of 10 μL of 50n mol Aβ(25-35), a unilateral injection of endothelin-1 into the right striatum, or Aβ and endothelin-1 administration in combination. Following a recovery period, rats were tested in the 1-trial place learning variant of the Morris water task followed by an ambiguous discriminative fear-conditioning to context task. After behavioural assessment, rats were euthanized, and representative sections of the medial septum were analyzed for differences in choline-acetyltransferase (ChAT) immunohistochemistry. No differences were observed in spatial working memory, but the combined effect of Aβ and stroke resulted in deficits in the discriminative fear-conditioning to context task. A trend towards decreased ChAT-positive staining in the medial septum was observed. This study indicates that Aβ and stroke in combination produce worse functional consequences than when experienced alone, furthering the concept of AD as a disease with multiple and complex etiologies.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Animals; Choline O-Acetyltransferase; Conditioning, Psychological; Disease Models, Animal; Endothelin-1; Fear; Infusions, Intraventricular; Learning; Male; Memory, Short-Term; Rats; Rats, Wistar; Septal Nuclei; Spatial Memory; Stroke

Endothelin-1 (ET-1) induced focal ischemia is increasingly being used as a preclinical model of stroke. Here, we described for the first time, the time course of neuronal death and infarct evolution during the first 7 days following ischemia.. We used hematoxylin and eosin (H&E) staining to evaluate infarct progression and Fluoro-Jade C (FJC) to quantify neuronal degeneration at 24, 48, 72h and 7 days after ET-1 injection to the forelimb motor cortex in Sprague-Dawley rats.. We found that infarct volume and neuronal degeneration are maximal at 24h post-stroke. Neuronal degeneration is also significantly reduced within 7 days of stroke induction.. This study is the first to provide a direct evaluation of both infarct volume evolution and neuronal death time course following ET-1 induced focal ischemia in the forelimb motor cortex.. This study describes the short-term time course of neuronal death and brain injury in the ET-1 stroke model, which provides a significant reference when determining the appropriate time to commence neuroprotective or recovery promoting strategies.

Topics: Animals; Brain Ischemia; Cell Count; Cell Death; Disease Models, Animal; Disease Progression; Endothelin-1; Forelimb; Male; Motor Cortex; Nerve Degeneration; Neurons; Rats, Sprague-Dawley; Stroke; Time Factors

Small white-matter infarcts of the internal capsule are clinically prevalent but underrepresented among currently available animal models of ischemic stroke. In particular, the assessment of long-term outcome, a primary end point in clinical practice, has been challenging due to mild deficits and the rapid and often complete recovery in most experimental models. We, therefore, sought to develop a focal white-matter infarction model that can mimic the lasting neurologic deficits commonly observed in stroke patients. The potent vasoconstrictor endothelin-1 (n=24) or vehicle (n=9) was stereotactically injected into the internal capsule at one of three antero-posterior levels (1, 2, or 3 mm posterior to bregma) in male Sprague-Dawley rats. Endothelin-injected animals showed highly focal (~1 mm(3)) and reproducible ischemic infarcts, with severe axonal and myelin loss accompanied by cellular infiltration when examined 2 and 4 weeks after injection. Only those rats injected with endothelin-1 at the most posterior location developed robust and pure-motor deficits in adhesive removal, cylinder and foot-fault tests that persisted at 1 month, without detectable sensory impairments. In summary, we present an internal capsule stroke model optimized to produce lasting pure-motor deficits in rats that may be suitable to study neurologic recovery and rehabilitation after white-matter injury.

Topics: Animals; Axons; Disease Models, Animal; Endothelin-1; Internal Capsule; Male; Motor Skills; Myelin Sheath; Rats; Rats, Sprague-Dawley; Stroke; White Matter

In a porcine ischemic stroke model, we sought to compare the acute predicted infarct core volume (PIV) defined by CT perfusion (CTP)-hemodynamic parameters and MR-diffusion-weighted imaging (MR-DWI)/apparent diffusion coefficient (ADC), with the true infarct core volume (TIV) as defined by histology. Ten Duroc-cross pigs had a CTP scan prior to injection of endothelin-1 (ET-1) into the left striatum. CTP scans were used to monitor ischemic progression. A second dose of ET-1 was injected 2 h from the first injection. The animal was moved to a 3-T MRI scanner where DWI was performed. CTP imaging was acquired immediately after the MR imaging. Next, the brain was removed and stained with tetrazolium chloride (TTC). Linear regression and Bland-Altman plots were used to correlate the PIV measured by each imaging modality to that of the TIV from the histological gold standard. The CTP-cerebral blood flow (CBF) parameter had the highest R (2) value and slope closest to unity, while the CTP-cerebral blood volume (CBV) had the lowest R(2) value and slope furthest away from unity. The CTP-CBF • CBV product parameter had a higher R(2) value but lower slope than both MR parameers. The best Bland-Altman agreement was observed with the CTP-CBF parameter. PIV from MR-DWI, ADC, and CTP-CBF overestimated the TIV defined with histology. We show that the PIV defined with absolute gray and white matter CT-CBF thresholds correlates best with the TIV and is similar to both MR-DWI and ADC-defined PIVs. Further, the acute CBF • CBV mismatch may not indicate penumbral tissue in the acute stroke setting.

Topics: Animals; Brain; Cerebral Infarction; Corpus Striatum; Diffusion Magnetic Resonance Imaging; Disease Models, Animal; Endothelin-1; Neuroimaging; Regression Analysis; Stroke; Swine; Tomography, X-Ray Computed

Central post-stroke pain (CPSP) is a neuropathic pain syndrome that often develops in a delayed manner after thalamic stroke. Here, we describe a new model of CPSP by stereotaxic thalamic injection of endothelin-1. Stroke rats (n = 12), but not saline-injected controls (n = 12), developed a progressive, contralateral cutaneous thermal hyperalgesia over 4 weeks, without motor deficits. Lesions were highly focal and mainly affected the ventral posterior thalamic complex. Tchis model reproduces the infarct location and delayed hypersensitivity typical of CPSP, and may be useful to investigate its pathophysiology and test therapies targeting recovery and pain after thalamic stroke.

Topics: Animals; Disease Models, Animal; Endothelin-1; Hot Temperature; Hyperalgesia; Male; Rats, Sprague-Dawley; Stroke; Thalamus

To aid in development of chronic stage treatments for sensorimotor deficits induced by ischemic stroke, we investigated the effects of GABA antagonism on brain structure and fine skilled reaching in a rat model of focal ischemia induced via cortical microinjections of endothelin-1 (ET-1). Beginning 7 days after stroke, animals were administered a gamma-aminobutyric acid (GABAA) inverse agonist, L-655,708, at a dose low enough to afford α5-GABAA receptor specificity. A week after stroke, the ischemic lesion comprised a small hypointense necrotic core (6±1 mm(3)) surrounded by a large (62±11 mm(3)) hyperintense perilesional region; the skilled reaching ability on the Montoya staircase test was decreased to 34%±2% of the animals' prestroke performance level. On L-655,708 treatment, animals showed a progressive decrease in total stroke volume (13±4 mm(3) per week), with no change in animals receiving placebo. Concomitantly, treated animals' skilled reaching progressively improved by 9%±1% per week, so that after 2 weeks of treatment, these animals performed at 65%±6% of their baseline ability, which was 25%±11% better than animals given placebo. These data indicate beneficial effects of delayed, sustained low-dose GABAA antagonism on neuroanatomic injury and skilled reaching in the chronic stage of stroke recovery in an ET-1 rat model of focal ischemia.

Topics: Animals; Behavior, Animal; Brain Ischemia; Endothelin-1; GABA Antagonists; Heart Rate; Imidazoles; Male; Motor Skills; Necrosis; Oxygen Consumption; Rats; Rats, Sprague-Dawley; Receptors, GABA-A; Recovery of Function; Respiratory Rate; Stroke; Stroke Volume

The cylinder test is routinely used to predict focal ischemic damage to the forelimb motor cortex in rodents. When placed in the cylinder, rodents explore by rearing and touching the walls of the cylinder with their forelimb paws for postural support. Following ischemic injury to the forelimb sensorimotor cortex, rats rely more heavily on their unaffected forelimb paw for postural support resulting in fewer touches with their affected paw which is termed forelimb asymmetry. In contrast, focal ischemic damage in the mouse brain fails to result in comparable consistent deficits in forelimb asymmetry. While forelimb asymmetry deficits are infrequently observed, mice do demonstrate a novel behaviour post stroke termed "paw-dragging". Paw-dragging is the tendency for a mouse to drag its affected paw along the cylinder wall rather than directly push off from the wall when dismounting from a rear to a four-legged stance. We have previously demonstrated that paw-dragging behaviour is highly sensitive to small cortical ischemic injuries to the forelimb motor cortex. Here we provide a detailed protocol for paw-dragging analysis. We define what a paw-drag is and demonstrate how to quantify paw-dragging behaviour. The cylinder test is a simple and inexpensive test to administer and does not require pre-training or food deprivation strategies. In using paw-dragging analysis with the cylinder test, it fills a niche for predicting cortical ischemic injuries such as photothrombosis and Endothelin-1 (ET-1)-induced ischemia--two models that are ever-increasing in popularity and produce smaller focal injuries than middle cerebral artery occlusion. Finally, measuring paw-dragging behaviour in the cylinder test will allow studies of functional recovery after cortical injury using a wide cohort of transgenic mouse strains where previous forelimb asymmetry analysis has failed to detect consistent deficits.

Topics: Animals; Brain Injuries; Brain Ischemia; Disease Models, Animal; Endothelin-1; Forelimb; Male; Mice; Motor Cortex; Rats; Recovery of Function; Stroke

Following unilateral stroke, the contralateral (paretic) body side is often severely impaired, and individuals naturally learn to rely more on the nonparetic body side, which involves learning new skills with it. Such compensatory hyper-reliance on the "good" body side, however, can limit functional improvements of the paretic side. In rats, motor skill training with the nonparetic forelimb (NPT) following a unilateral infarct lessens the efficacy of rehabilitative training, and reduces neuronal activation in perilesion motor cortex. However, the underlying mechanisms remain unclear. In the present study, we investigated how forelimb movement representations and synaptic restructuring in perilesion motor cortex respond to NPT and their relationship with behavioral outcomes. Forelimb representations were diminished as a result of NPT, as revealed with intracortical microstimulation mapping. Using transmission electron microscopy and stereological analyses, we found that densities of axodendritic synapses, especially axo-spinous synapses, as well as multiple synaptic boutons were increased in the perilesion cortex by NPT. The synaptic density was negatively correlated with the functional outcome of the paretic limb, as revealed in reaching performance. Furthermore, in animals with NPT, there was dissociation between astrocytic morphological features and axo-spinous synaptic density in perilesion motor cortex, compared with controls. These findings demonstrate that skill learning with the nonparetic limb following unilateral brain damage results in aberrant synaptogenesis, potentially of transcallosal projections, and this seems to hamper the functionality of the perilesion motor cortex and the paretic forelimb.

Topics: Animals; Astrocytes; Brain Mapping; Disease Models, Animal; Endothelin-1; Exercise Therapy; Forelimb; Functional Laterality; Male; Microscopy, Electron, Transmission; Motor Cortex; Motor Skills; Movement; Muscle Strength; Neuronal Plasticity; Presynaptic Terminals; Rats; Rats, Long-Evans; Stroke; Stroke Rehabilitation; Synapses; Time Factors

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

Topics: Animals; Apoptosis; Basic Helix-Loop-Helix Transcription Factors; Cell Differentiation; Cell Movement; Cell Proliferation; Diffusion Tensor Imaging; Disease Models, Animal; Endothelin-1; Magnetic Resonance Imaging; Male; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Myelin Basic Protein; Myelin Proteins; Nerve Tissue Proteins; Nogo Proteins; Oligodendrocyte Transcription Factor 2; Oligodendroglia; Proteome; Proteomics; Rats; Rats, Sprague-Dawley; Recovery of Function; Stroke; White Matter

Cognitive impairments are prevalent following clinical stroke; however, preclinical research has focused almost exclusively on motor deficits. In order to conduct systematic evaluations into the nature of post-stroke cognitive dysfunction and recovery, it is crucial to develop focal stroke models that predominantly affect cognition while leaving motor function intact. Herein, we evaluated a range of cognitive functions 1-4 months following focal medial prefrontal cortex (mPFC) stroke using a battery of tests. Male Sprague-Dawley rats underwent focal ischemia induced in the mPFC using bilateral intracerebral injections of endothelin-1, or sham surgery. Cognitive function was assessed using an open field, several object recognition tests, attentional set-shifting, light-dark box, spontaneous alternation, Barnes maze, and win-shift/win-stay tests. Prefrontal cortex damage resulted in significant changes in object recognition function, behavioural flexibility, and anxiety-like behaviour, while spontaneous alternation and locomotor function remained intact. These deficits are similar to the cognitive deficits following stroke in humans. Our results suggest that this model may be useful for identifying and developing potential therapies for improving post-stroke cognitive dysfunction.

Topics: Animals; Chronic Disease; Cognition; Cognition Disorders; Disease Models, Animal; Endothelin-1; Male; Motor Activity; Neuropsychological Tests; Prefrontal Cortex; Rats, Sprague-Dawley; Severity of Illness Index; Stroke

Acid-sensing ion channel 1a (ASIC1a) is the primary acid sensor in mammalian brain and plays a major role in neuronal injury following cerebral ischemia. Evidence that inhibition of ASIC1a might be neuroprotective following stroke was previously obtained using "PcTx1 venom" from the tarantula Psalmopeous cambridgei. We show here that the ASIC1a-selective blocker PcTx1 is present at only 0.4% abundance in this venom, leading to uncertainty as to whether the observed neuroprotective effects were due to PcTx1 blockade of ASIC1a or inhibition of other ion channels and receptors by the hundreds of peptides and small molecules present in the venom. We therefore examined whether pure PcTx1 is neuroprotective in a conscious model of stroke via direct inhibition of ASIC1a. A focal reperfusion model of stroke was induced in conscious spontaneously hypertensive rats (SHR) by administering endothelin-1 to the middle cerebral artery via a surgically implanted cannula. Two hours later, SHR were treated with a single intracerebroventricular (i.c.v.) dose of PcTx1 (1 ng/kg), an ASIC1a-inactive mutant of PcTx1 (1 ng/kg), or saline, and ledged beam and neurological tests were used to assess the severity of symptomatic changes. PcTx1 markedly reduced cortical and striatal infarct volumes measured 72 h post-stroke, which correlated with improvements in neurological score, motor function and preservation of neuronal architecture. In contrast, the inactive PcTx1 analogue had no effect on stroke outcome. This is the first demonstration that selective pharmacological inhibition of ASIC1a is neuroprotective in conscious SHRs, thus validating inhibition of ASIC1a as a potential treatment for stroke.

Topics: Acid Sensing Ion Channel Blockers; Acid Sensing Ion Channels; Animals; Apoptosis; Brain; Cell Survival; Endothelin-1; Infarction, Middle Cerebral Artery; Male; Motor Activity; Mutation; Neurons; Neuroprotective Agents; Peptides; Rats, Inbred SHR; Severity of Illness Index; Spider Venoms; Spiders; Stroke

Forced limb-use can enhance neurogenesis and behavioral recovery as well as increasing the level of stromal cell-derived factor-1 (SDF-1) in stroke rats. We examined whether the SDF-1/CXCR4 pathway is involved in the enhanced neurogenesis and promoted behavioral recovery induced by forced limb-use in the chronic phase of stroke.. The CXCR4 antagonist, AMD3100, was used to block the SDF-1/CXCR4 pathway in the ischemic rats. Brain ischemia was induced by endothelin-1. One week after ischemia, the unimpaired forelimb of rats was immobilized for 3 weeks. The proliferation, migration, and survival of DCX-positive cells in the subventricular zone (SVZ), and the dendritic complexity of DCX-positive cells in the dentate gyrus (DG), as well as the inflammatory response in the infarcted striatum were analyzed by immunohistochemistry. Functional recovery was assessed in beam-walking and water maze tests.. Forced limb-use enhanced the proliferation, migration, dendritic complexity and the survival of newborn neurons. Furthermore, forced limb-use suppressed the inflammatory response and improved both motor and cognitive functions after stroke. AMD3100 significantly abrogated the enhanced neurogenesis and behavioral recovery induced by forced limb-use without influencing the inflammatory response.. SDF-1/CXCR4 pathway seems to be involved in the enhancement of neurogenesis and behavioral recovery induced by post-stroke forced limb-use.

Topics: Animals; Benzylamines; Brain; Brain Ischemia; Central Nervous System Agents; Chemokine CXCL12; Cyclams; Disease Models, Animal; Doublecortin Protein; Endothelin-1; Forelimb; Heterocyclic Compounds; Immobilization; Male; Maze Learning; Motor Activity; Musculoskeletal Manipulations; Neurogenesis; Neurons; Random Allocation; Rats, Wistar; Receptors, CXCR4; Recovery of Function; Stroke; Stroke Rehabilitation

Small subcortical infarcts account for 25% of all ischemic strokes. Although once considered to be a small vessel disease with a favorable outcome, recent studies have reported relatively poor long-term prognoses following small subcortical infarcts. Limited pre-clinical modeling has hampered understanding of the etiology and development of treatments for this disease. Therefore, we attempted to develop a new experimental model of small subcortical infarcts in mice to investigate pathophysiological changes in the corticospinal tract and assess long-term behavioral performance. The vasoconstrictor peptide, endothlin-1 (ET-1), in combination with the nitric oxide synthase inhibitor, N(G)-nitro-l-arginine methyl ester (l-NAME), were injected into the internal capsule of mice. Histological and behavioral tests were performed 0-8 weeks after the injection. The ET-1/l-NAME injection resulted in severe neurological deficits that continued for up to 8 weeks. The loss of axons and myelin surrounded by reactive gliosis was identified in the region of the injection, in which the vasoconstriction of microvessels was also observed. Moreover, a tract-tracing study revealed an interruption in axonal flow at the internal capsule. The present model of small subcortical infarcts is unique and novel due to the reproduction of neurological deficits that continue for a long period, up to 8 weeks, as well as the use of mice as experimental animals. The reproducibility, simplicity, and easy adoptability make the present model highly appealing for use in further pre-clinical studies on small subcortical infarcts.

Topics: Animals; Cerebral Infarction; Disease Models, Animal; Endothelin-1; Internal Capsule; Male; Mice; Mice, SCID; NG-Nitroarginine Methyl Ester; Psychomotor Performance; Stroke; Time Factors

Small (lacunar) infarcts frequently arise in frontal and midline thalamic regions in the absence of major stroke. Damage to these areas often leads to impairment of executive function likely as a result of interrupting connections of the prefrontal cortex. Thus, patients experience frontal-like symptoms such as impaired ability to shift ongoing behavior and attention. In contrast, executive dysfunction has not been demonstrated in rodent models of stroke, thereby limiting the development of potential therapies for human executive dysfunction. Male Sprague-Dawley rats (n=40) underwent either sham surgery or bilateral endothelin-1 injections in the mediodorsal nucleus of the thalamus or in the medial prefrontal cortex. Executive function was assessed using a rodent attention set shifting test that requires animals to shift attention to stimuli in different stimulus dimensions. Medial prefrontal cortex ischemia impaired attention shift performance between different stimulus dimensions while sparing stimulus discrimination and attention shifts within a stimulus dimension, indicating a selective attention set-shift deficit. Rats with mediodorsal thalamic lacunar damage did not exhibit a cognitive impairment relative to sham controls. The selective attention set shift impairment observed in this study is consistent with clinical data demonstrating selective executive disorders following stroke within specific sub-regions of frontal cortex. These data contribute to the development and validation of a preclinical animal model of executive dysfunction, that can be employed to identify potential therapies for ameliorating cognitive deficits following stroke.

Topics: Animals; Attention; Behavior, Animal; Brain Ischemia; Discrimination Learning; Endothelin-1; Executive Function; Male; Prefrontal Cortex; Rats; Rats, Sprague-Dawley; Reversal Learning; Set, Psychology; Stroke

Constraint induced movement therapy (CIMT), which forces use of the impaired arm following stroke, improves functional recovery. The mechanisms underlying recovery are not well understood, necessitating further investigation into how rehabilitation may affect neuroplasticity using animal models. Animal motivation and stress make modelling CIMT in animals challenging. We have shown that following focal ischemia, voluntary forced use therapy using pet activity balls could engage the impaired forelimb and result in a modest acceleration in recovery. In this study, we investigated the effects of a more intensive appetitively motivated regimen that included task specific reaching exercises. Adult male Sprague Dawley rats were subjected to focal unilateral stroke using intracerebral injections of endothelin-1 or sham surgery. Three days later, stroke animals were assigned to daily rehabilitation or control therapy. Rehabilitation consisted of 30 min of generalized movement sessions in activity balls, followed by 30 min of voluntary task-specific movement using reaching boxes. Rats were tested weekly to measure forelimb deficit and recovery. After 30 days, animals were euthanized and tissue was examined for infarct volume, brain derived neurotrophic factor expression, and the presence of new neurons using doublecortin immunohistochemistry. Rehabilitation resulted in a significant acceleration of forelimb recovery in several tests, and a significant increase in the number of doublecortin-expressing cells. Furthermore, while the proportion of cells expressing BDNF in the peri-infarct region did not change, there was a shift in the cellular origin of expressed BDNF, resulting in significantly more non-neuronal, non-astrocytic BDNF, presumed to be of microglial origin.

Topics: Animals; Brain; Disease Models, Animal; Doublecortin Protein; Endothelin-1; Exercise Therapy; Feeding Behavior; Forelimb; Functional Laterality; Glial Fibrillary Acidic Protein; Locomotion; Male; Phosphopyruvate Hydratase; Psychomotor Performance; Rats; Rats, Sprague-Dawley; Recovery of Function; Restraint, Physical; Stroke; Stroke Rehabilitation; Time Factors

Numerous clinical and epidemiological reports indicate that patients with history of vascular illness such as stroke are more likely to develop dementia as the clinical manifestation of Alzheimer's disease. However, there are little data regarding the pathologic mechanisms that link vascular risk factors to the factors associated with dementia onset. We provide evidence that suggests intriguing detrimental interactions between stroke and β-amyloid (Aβ) toxicity in the hippocampus. Stroke was induced by unilateral striatal injection of endothelin-1, the potent vasoconstrictor. Aβ toxicity was modeled by bilateral intracerebroventricular injections of the toxic fragment Aβ. Gross morphologic changes in comorbid Aβ and stroke rats were enlargement of the lateral ventricles with concomitant shrinkage of the hippocampus. The hippocampus displayed a series of synergistic biochemical alterations, including microgliosis, deposition of Aβ precursor protein fragments, and cellular degeneration. In addition, there was bilateral induction of connexin43, reduced neuronal survival, and impaired dendritic development of adult-born immature neurons in the dentate gyrus of these rats compared with either rats alone. Behaviorally, there was impairment in the hippocampal-based discriminative fear-conditioning to context task indicating learning and memory deficit. These results suggest an insight into the relationship between hippocampal atrophy, pathology, and functional impairment. Our work not only highlights the exacerbated pathology that emerges when Aβ toxicity and stroke occur comorbidly but also demonstrates that this comorbid rat model exhibits physiopathology that is highly characteristic of the human condition.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Atrophy; Connexin 43; Dementia; Disease Models, Animal; Endothelin-1; Hippocampus; Humans; Injections, Intraventricular; Male; Stroke; Vasoconstrictor Agents

Evidence indicates that angiotensin II type 2 receptors (AT2R) exert cerebroprotective actions during stroke. A selective non-peptide AT2R agonist, Compound 21 (C21), has been shown to exert beneficial effects in models of cardiac and renal disease, as well as hemorrhagic stroke. Here, we hypothesize that C21 may exert beneficial effects against cerebral damage and neurological deficits produced by ischemic stroke. We determined the effects of central and peripheral administration of C21 on the cerebral damage and neurological deficits in rats elicited by endothelin-1 induced middle cerebral artery occlusion (MCAO), a model of cerebral ischemia. Rats infused centrally (intracerebroventricular) with C21 before endothelin-1 induced MCAO exhibited significant reductions in cerebral infarct size and the neurological deficits produced by cerebral ischemia. Similar cerebroprotection was obtained in rats injected systemically (intraperitoneal) with C21 either before or after endothelin-1 induced MCAO. The protective effects of C21 were reversed by central administration of an AT2R inhibitor, PD123319. While C21 did not alter cerebral blood flow at the doses used here, peripheral post-stroke administration of this agent significantly attenuated the MCAO-induced increases in inducible nitric oxide synthase, chemokine (C-C) motif ligand 2 and C-C chemokine receptor type 2 mRNAs in the cerebral cortex, indicating that the cerebroprotective action is associated with an anti-inflammatory effect. These results strengthen the view that AT2R agonists may have potential therapeutic value in ischemic stroke, and provide the first evidence of cerebroprotection induced by systemic post stroke administration of a selective AT2R agonist.

Topics: Angiotensin II Type 2 Receptor Blockers; Animals; Brain Infarction; Brain Ischemia; CD11b Antigen; Cerebrovascular Circulation; Cytokines; Disease Models, Animal; Dose-Response Relationship, Drug; Endothelin-1; Glial Fibrillary Acidic Protein; Imidazoles; Male; Nitric Oxide Synthase Type II; Peroxidase; Pyridines; Rats; Rats, Sprague-Dawley; Stroke; Sulfonamides; Thiophenes; Time Factors

The objective of this study is to investigate the association between SNP polymorphisms of endothelin-1 (EDN1) and endothelin receptor (EDNRA and EDNRB) gene and ischemic stroke (IS) in the Chinese Han population in northern. A case-control study was introduced. We genotyped eight SNPs (rs1800541, rs2070699, and rs5370 in EDN1 gene; rs1801708, rs5333, and rs5335 in EDNRA gene; and rs3818416 and rs5351 in EDNRB gene) and calculated their polymorphic distribution in control group, IS group, and the IS subgroups. In male population, EDN1 gene rs2070699 G allele increased the incidence risk to 1.78 times (P = 0.009; OR 1.78; 95 % CI 1.15-2.75) and the risk of morbidity of rs5370 T allele carrying increased to 1.49 times (P = 0.048; OR 1.49; 95 % CI 1.00-2.21). EDNRA gene mutation rs5335 homozygous CC morbidity risk was significantly lower (P = 0.016; OR 0.52; 95 % CI 0.31-0.88). In the female population, the mutant homozygous AA cancer risk was significantly higher than G allele carriers (P = 0.019; OR 2.65; 95 % CI 1.18-6.00) on EDNRA gene rs1801708. In EDN1 gene, T allele of rs5370 and G allele of rs2070699 may be IS incidence risk factors in Northern Han male population. A allele of rs1801708 in EDNRA gene can increase the risk of IS in Northern Han women population.

Topics: Brain Ischemia; Case-Control Studies; Endothelin-1; Female; Genotype; Humans; Male; Middle Aged; Polymorphism, Single Nucleotide; Receptor, Endothelin A; Receptor, Endothelin B; Stroke

To investigate the protective effect of catalpol on cerebral ischaemia/reperfusion (CI/R) injury in gerbils and further explore the underlying mechanism.. A gerbil model of CI/R was prepared by bilateral common carotid occlusion for 10 min followed by 6 h reperfusion. Catalpol (5, 10 or 20 mg/kg per day) was injected intraperitoneally for 3 days before the carotid occlusion. Stroke index was measured during the reperfusion. The contents of endogenous neuropeptides, endothelin-1 (ET-1) and calcitonin gene-related peptide in plasma were evaluated by radioimmunoassay. Superoxide dismutase (SOD) and malondialdehyde (MDA) in brain tissue homogenate were also examined.. The results showed that catalpol significantly improved the stroke index compared with CI/R control group (P < 0.05 or P < 0.01). Catalpol significantly increased the activity of SOD at the doses of 10 and 20 mg/kg (P ≤ 0.05), decreased the brain MDA content and the plasma level of ET-1 at the doses of 10 and 20 mg/kg (P ≤ 0.01).. These data suggested that the efficacy of catalpol pretreatment on CI/R injury may be attributed to reduction of free radicals and inhibition of lipid peroxidation and ET-1 production.

Topics: Animals; Brain; Brain Ischemia; Calcitonin Gene-Related Peptide; Cerebral Infarction; Disease Models, Animal; Endothelin-1; Female; Free Radicals; Gerbillinae; Injections, Intraperitoneal; Iridoid Glucosides; Lipid Peroxidation; Male; Malondialdehyde; Neuropeptides; Oxidative Stress; Phytotherapy; Plant Extracts; Rehmannia; Reperfusion Injury; Stroke; Superoxide Dismutase

Rehabilitation is the only treatment option for chronic stroke deficits, but unfortunately, it often provides incomplete recovery. In this study, a novel combination of growth factor administration and rehabilitation therapy was used to facilitate functional recovery in a rat model of cortical stroke.. Ischemia was induced via injection of endothelin-1 into the sensorimotor cortex. This was followed by either a 2-week infusion of epidermal growth factor and erythropoietin or artificial cerebrospinal fluid into the ipsilateral lateral ventricle. Two weeks after ischemia, animals began an 8-week enriched rehabilitation program. Functional recovery was assessed after ischemia using the Montoya staircase-reaching task, beam-traversing, and cylinder test of forelimb asymmetry.. The combination of growth factor infusion and rehabilitation led to a significant acceleration in recovery in the staircase task. When compared with controls, animals receiving the combination treatment attained significant recovery of function at 4 weeks after stroke, whereas those receiving rehabilitation alone did not recover until 10 weeks. Significant recovery was also observed on the beam-traversing and cylinder tasks.. Combining behavioral rehabilitation with growth factor infusion accelerates motor recovery. These data suggest a promising new avenue of combination therapies that may have the potential to reduce the rehabilitation time necessary to recover from sensorimotor deficits arising from stroke.

Topics: Animals; Chronic Disease; Disease Models, Animal; Endothelin-1; Epidermal Growth Factor; Erythropoietin; Male; Motor Activity; Rats; Rats, Sprague-Dawley; Stroke; Stroke Rehabilitation

Stroke is an acute cerebrovascular disease with high incidence, morbidity, and mortality. Preischemic treadmill training has been shown to be effective in improving behavioral and neuropathologic indices after cerebral ischemia. However, the exact neuroprotective mechanism of preischemic treadmill training against ischemic injury has not been elucidated clearly. The present study investigated whether preischemic treadmill training could protect the brain from ischemic injury via regulating cerebral blood flow (CBF) and endothelin 1 (ET-1). We analyzed the CBF by laser speckle imaging and ET-1 expression by an enzyme-linked immunosorbent assay using an ischemic rat model with preischemic treadmill training. Generally speaking, ET-1 expression decreased and CBF increased significantly in the pretreadmill group. It is worth noting that ET-1 expression is increased at 24 hours of reperfusion in the pretreadmill group compared with the level of the time after middle cerebral artery occlusion. These changes were followed by significant changes in neurologic deficits and cerebral infarct volume. This study indicated that preconditioning exercise protected brain from ischemic injury through the improvement of CBF and regulation of ET-1 expression, which may be a novel component of the neuroprotective mechanism of preischemic treadmill training against brain injury.

Topics: Animals; Brain; Brain Ischemia; Cerebrovascular Circulation; Disease Models, Animal; Endothelin-1; Infarction, Middle Cerebral Artery; Ischemic Preconditioning; Male; Physical Conditioning, Animal; Rats; Rats, Sprague-Dawley; Stroke

The extent of stroke damage in patients affects the range of subsequent pathophysiological responses that influence recovery. Here we investigate the effect of lesion size on development of new blood vessels as well as inflammation and scar formation and cellular responses within the subventricular zone (SVZ) following transient focal ischemia in rats (n = 34). Endothelin-1-induced stroke resulted in neurological deficits detected between 1 and 7 days (P<0.001), but significant recovery was observed beyond this time. MCID image analysis revealed varying degrees of damage in the ipsilateral cortex and striatum with infarct volumes ranging from 0.76-77 mm3 after 14 days, where larger infarct volumes correlated with greater functional deficits up to 7 days (r = 0.53, P<0.05). Point counting of blood vessels within consistent sample regions revealed that increased vessel numbers correlated significantly with larger infarct volumes 14 days post-stroke in the core cortical infarct (r = 0.81, P<0.0001), core striatal infarct (r = 0.91, P<0.005) and surrounding border zones (r = 0.66, P<0.005; and r = 0.73, P<0.05). Cell proliferation within the SVZ also increased with infarct size (P<0.01) with a greater number of Nestin/GFAP positive cells observed extending towards the border zone in rats with larger infarcts. Lesion size correlated with both increased microglia and astrocyte activation, with severely diffuse astrocyte transition, the formation of the glial scar being more pronounced in rats with larger infarcts. Thus stroke severity affects cell proliferation within the SVZ in response to injury, which may ultimately make a further contribution to glial scar formation, an important factor to consider when developing treatment strategies that promote neurogenesis.

Topics: Animals; Brain; Brain Infarction; Cell Differentiation; Cell Movement; Cell Proliferation; Consciousness; Endothelin-1; Lateral Ventricles; Macrophage Activation; Male; Microglia; Neovascularization, Physiologic; Rats; Rats, Wistar; Stroke

Despite the availability of numerous transgenic mouse lines to study the role of individual genes in promoting neural repair following stroke, few studies have availed of this technology, primarily due to the lack of a reproducible ischemic injury model in the mouse. Intracortical injections of Endothelin-1 (ET1) a potent vasoconstrictive agent, reliably produces focal infarcts with concomitant behavioral deficits in rats. In contrast, ET1 infarcts in mice are significantly smaller and do not generate consistent behavioral deficits.. We have modified the ET1 ischemia model to target the anterior forelimb motor cortex (aFMC) and show that this generates a reproducible focal ischemic injury in mice with consistent behavioral deficits. Furthermore, we have developed a novel analysis of the cylinder test by quantifying paw-dragging behavior.. ET1 injections which damage deep layer neurons in the aFMC generate reproducible deficits on the staircase test. Cylinder test analysis showed no forelimb asymmetry post-injection; however, we observed a novel paw-dragging behavior in mice which is a positive sign of damage to the FMC.. Previous ET1 studies have demonstrated inconsistent behavioral deficits; however, targeting ET1 injections to the aFMC reliably results in staircase deficits. We show that analysis of paw-dragging behavior in the cylinder test is a more sensitive measure of damage to the FMC than the classical forelimb asymmetry analysis.. We have developed a focal ischemic injury model in the mouse that results in reproducible behavioral deficits and can be used to test future regenerative therapies.

Topics: Animals; Brain Ischemia; Cell Count; Disease Models, Animal; Endothelin-1; Forelimb; Immunohistochemistry; Male; Mice; Motor Cortex; Movement Disorders; Neurons; Random Allocation; Reproducibility of Results; Severity of Illness Index; Stroke

The mechanism underlying forced limb-use -induced structural plasticity remains to be studied. We examined whether the cyclic adenosine monophosphate (cAMP)-mediated signal transduction pathway was involved in brain plasticity and promoted behavioral recovery induced by forced limb-use after stroke.. Adult rats were divided into a sham group, an ischemia group, an ischemia group with forced limb-use, and an ischemia group with forced limb-use and infusion of N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinoline-sulfonamide (H89). Forced limb-use began on post-stroke day 7. Biotinylated dextran amine (BDA) was injected into the sensorimotor cortex on post-stroke day 14. Behavioral recovery was evaluated on post-stroke days 29 to 32, and the levels of cAMP, PKA C-α, phosphorylated CREB (pCREB), synaptophysin, PSD-95, BDA, and BrdU/NeuN were measured.. The number of midline-crossing axons and the expression levels of synaptophysin and PSD-95 were increased after forced limb-use. Forced limb-use enhanced the survival of the newborn neurons and increased the levels of cAMP, PKA C-α and pCREB. These were significantly suppressed by H89. Behavioral performance improved with forced limb-use and was reversed with H89.. Enhanced structural plasticity and the behavioral recovery promoted by post-stroke forced limb-use are suggested to be mediated through the cAMP/PKA/CREB signal transduction pathway.

Topics: Animals; Biotin; Brain; CREB-Binding Protein; Cyclic AMP; Dextrans; Disease Models, Animal; Disks Large Homolog 4 Protein; Endothelin-1; Extremities; Intracellular Signaling Peptides and Proteins; Isoquinolines; Locomotion; Male; Membrane Proteins; Neuronal Plasticity; Protein Kinase C-alpha; Protein Kinase Inhibitors; Rats; Rats, Wistar; Restraint, Physical; Stroke; Stroke Rehabilitation; Sulfonamides; Synaptophysin

Stroke causes disability and mortality worldwide and is divided into ischemic and hemorrhagic subtypes. Although clinical trials suggest distinct recovery profiles for ischemic and hemorrhagic events, this is not conclusive due to stroke heterogeneity. The aim of this study was to produce similar brain damage, using experimental models of ischemic (IS) and hemorrhagic (HS) stroke and evaluate the motor spontaneous recovery profile. We used 31 Wistar rats divided into the following groups: Sham (n=7), ischemic (IS) (n=12) or hemorrhagic (HS) (n=12). Brain ischemia or hemorrhage was induced by endotelin-1 (ET-1) and collagenase type IV-S (collagenase) microinjections, respectively. All groups were evaluated in the open field, cylinder and ladder walk behavioral tests at distinct time points as from baseline to 30 days post-surgery (30 PS). Histological and morphometric analyses were used to assess the volume of lost tissue and lesion length. Present results reveal that both forms of experimental stroke had a comparable long-term pattern of damage, since no differences were found in volume of tissue lost or lesion size 30 days after surgery. However, behavioral data showed that hemorrhagic rats were less impaired at skilled walking than ischemic ones at 15 and 30 days post-surgery. We suggest that experimentally comparable stroke design is useful because it reduces heterogeneity and facilitates the assessment of neurobiological differences related to stroke subtypes; and that spontaneous skilled walking recovery differs between experimental ischemic and hemorrhagic insults.

Topics: Animals; Brain; Brain Ischemia; Collagenases; Endothelin-1; Intracranial Hemorrhages; Male; Microinjections; Motor Activity; Motor Skills; Rats; Recovery of Function; Stroke

Stroke is the number one cause of disability and third leading cause of death in the world, costing an estimated $70 billion in the United States in 2009. Several models of cerebral ischemia have been developed to mimic the human condition of stroke. It has been suggested that up to 80% of all strokes result from ischemic damage in the middle cerebral artery (MCA) area. In the early 1990s, endothelin-1 (ET-1) was used to induce ischemia by applying it directly adjacent to the surface of the MCA after craniotomy. Later, this model was modified by using a stereotaxic injection of ET-1 adjacent to the MCA to produce focal cerebral ischemia. The main advantages of this model include the ability to perform the procedure quickly, the ability to control artery constriction by altering the dose of ET-1 delivered, no need to manipulate the extracranial vessels supplying blood to the brain as well as gradual reperfusion rates that more closely mimics the reperfusion in humans. On the other hand, the ET-1 model has disadvantages that include the need for a craniotomy, as well as higher variability in stroke volume. This variability can be reduced with the use of laser Doppler flowmetry (LDF) to verify cerebral ischemia during ET-1 infusion. Factors that affect stroke variability include precision of infusion and the batch of the ET-1 used. Another important consideration is that although reperfusion is a common occurrence in human stroke, the duration of occlusion for ET-1 induced MCAO may not closely mimic that of human stroke where many patients have partial reperfusion over a period of hours to days following occlusion. This protocol will describe in detail the ET-1 induced MCAO model for ischemic stroke in rats. It will also draw attention to special considerations and potential drawbacks throughout the procedure.

Topics: Animals; Disease Models, Animal; Endothelin-1; Infarction, Middle Cerebral Artery; Laser-Doppler Flowmetry; Male; Middle Cerebral Artery; Rats; Rats, Sprague-Dawley; Stroke

Blood-brain-barrier (BBB) disruption, inflammation and thrombosis are important steps in the pathophysiology of acute ischemic stroke but are still inaccessible to therapeutic interventions. Rolipram specifically inhibits the enzyme phosphodiesterase (PDE) 4 thereby preventing the inactivation of the intracellular second messenger cyclic adenosine monophosphate (cAMP). Rolipram has been shown to relief inflammation and BBB damage in a variety of neurological disorders. We investigated the therapeutic potential of rolipram in a model of brain ischemia/reperfusion injury in mice. Treatment with 10mg/kg rolipram, but not 2 mg/kg rolipram, 2 h after 60 min of transient middle cerebral artery occlusion (tMCAO) reduced infarct volumes by 50% and significantly improved clinical scores on day 1 compared with vehicle-treated controls. Rolipram maintained BBB function upon stroke as indicated by preserved expression of the tight junction proteins occludin and claudin-5. Accordingly, the formation of vascular brain edema was strongly attenuated in mice receiving rolipram. Moreover, rolipram reduced the invasion of neutrophils as well as the expression of the proinflammatory cytokines IL-1β and TNFα but increased the levels of TGFβ-1. Finally, rolipram exerted antithrombotic effects upon stroke and fewer neurons in the rolipram group underwent apoptosis. Rolipram is a multifaceted antiinflammatory and antithrombotic compound that protects from ischemic neurodegeneration in clinically meaningful settings.

Topics: Animals; Blood-Brain Barrier; Brain Edema; Brain Injuries; Cytokines; Disease Models, Animal; Encephalitis; Endothelin-1; Hemodynamics; Infarction, Middle Cerebral Artery; Laser-Doppler Flowmetry; Male; Mice; Mice, Inbred C57BL; Nerve Tissue Proteins; Occludin; Phosphodiesterase 4 Inhibitors; Rolipram; Stroke; Thrombosis

Constraint-induced movement therapy (CIMT) improves functional outcome in patients with stroke possibly through structural plasticity. We hypothesized that CIMT could enhance axonal growth by overcoming the intrinsic growth-inhibitory signals, leading eventually to improved behavioral performance in stroke rats.. Focal cerebral ischemia was induced by intracerebral injection of endothelin-1. Adult Wistar rats were divided into a sham-operated group, an ischemic group, and an ischemic group treated with CIMT. CIMT started at postoperative day 7 and continued for 3 weeks. Biotinylated dextran amine was injected into the contralateral sensorimotor cortex at postoperative day 14 to trace crossing axons at the cervical spinal cord. The expressions of Nogo-A, Nogo receptor, RhoA, and Rho-associated kinase in the peri-infarct cortex, and the expressions of biotinylated dextran amine, growth associated protein-43, synaptophysin, vGlut1, and postsynaptic density-95 in the denervated spinal cord were measured by immunohistochemistry and Western blots. Behavioral recovery was analyzed at postoperative days 29 to 32.. Infarct volumes were not different between groups after stroke. CIMT significantly increased the length and the number of midline crossings of contralateral corticospinal axons to the denervated cervical spinal cord. CIMT significantly decreased the expressions of Nogo-A/Nogo receptor and RhoA/Rho-associated kinase in the peri-infarct cortex, and increased the expressions of growth associated protein-43, synaptophysin, vGlut1, and postsynaptic density-95 in the denervated cervical spinal cord. Behavioral performances assessed by the beam-walking test and the water maze test were improved significantly by CIMT.. CIMT promoted poststroke synaptic plasticity and axonal growth at least partially by overcoming the intrinsic growth-inhibitory signaling, leading to improved behavioral outcome.

Topics: Animals; Axons; Disease Models, Animal; Endothelin-1; GAP-43 Protein; GPI-Linked Proteins; Injections, Intraventricular; Male; Movement; Myelin Proteins; Neuronal Plasticity; Nogo Proteins; Nogo Receptor 1; Physical Therapy Modalities; Rats; Rats, Wistar; Receptors, Cell Surface; Restraint, Physical; rhoA GTP-Binding Protein; Signal Transduction; Stroke; Synaptophysin

Behavioral experience, in the form of skilled limb use, has been found to impact the structure and function of the central nervous system, affecting post-stroke behavioral outcome in both adaptive and maladaptive ways. Learning to rely on the less-affected, or non-paretic, body side is common following stroke in both humans and rodent models. In rats, it has been observed that skilled learning with the non-paretic forelimb following ischemic insult leads to impaired or delayed functional recovery of the paretic limb. Here we used a mouse model of focal motor cortical ischemic injury to examine the effects of non-paretic limb training following unilateral stroke. In addition, we exposed some mice to increased bimanual experience in the home cage following stroke to investigate the impact of coordinated dexterous limb use on the non-paretic limb training effect. Our results confirmed that skilled learning with the non-paretic limb impaired functional recovery following stroke in C56BL/6 mice, as it does in rats. Further, this effect was avoided when the skill learning of the non-paretic limb was coupled with increased dexterous use of both forelimbs in the home cage. These findings further establish the mouse as an appropriate model in which to study the neural mechanisms of recovery following stroke and extend previous findings to suggest that the dexterous coordinated use of the paretic and non-paretic limb can promote functional outcome following injury.

Topics: Analysis of Variance; Animals; Disease Models, Animal; Endothelin-1; Environment; Food Deprivation; Forelimb; Functional Laterality; Learning; Male; Mice; Mice, Inbred C57BL; Motor Skills; Paresis; Recovery of Function; Stroke; Stroke Rehabilitation; Time Factors

The aim of this study was to test the insulin-like growth factor-I (IGF-I) as a neuroprotective agent in a rat model for ischemic stroke and to compare its neuroprotective effects in conscious normotensive and spontaneously hypertensive rats. The effects of subcutaneous IGF-I injection were investigated in both rat strains using the endothelin-1 rat model for ischemic stroke. Motor-sensory functions were measured using the Neurological Deficit Score. Infarct size was assessed by Cresyl Violet staining. Subcutaneous administration of IGF-I resulted in significantly reduced infarct volumes and an increase in motor-sensory functions in normotensive rats. In these rats, IGF-I did not modulate blood flow in the striatum and had no effect on the activation of astrocytes as assessed by GFAP staining. In hypertensive rats, the protective effects of IGF-I were smaller and not always significant. Furthermore, IGF-I significantly reduced microglial activation in the cortex of hypertensive rats, but not in normotensive rats. More detailed studies are required to find out whether the reduction by IGF-I of microglial activation contributes to an impairment IGF-I treatment efficacy. Indeed, we have shown before that microglia in hypertensive rats have different properties compared to those in control rats, as they exhibit a reduced responsiveness to ischemic stroke and lipopolysaccharide.

Topics: Animals; Body Weight; Brain Ischemia; Endothelin-1; Glial Fibrillary Acidic Protein; Glucose; Humans; Hypertension; Immunohistochemistry; Injections, Subcutaneous; Insulin-Like Growth Factor I; Laser-Doppler Flowmetry; Macrophage Activation; Male; Microglia; Nervous System Diseases; Neuroprotective Agents; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Recombinant Proteins; Stroke; Telemetry

Neurodegeneration is a hallmark of most of the central nervous system (CNS) disorders including stroke. Recently inflammation has been implicated in pathogenesis of neurodegeneration and neurodegenerative diseases. The aim of this study was analysis of expression of several inflammatory markers and its correlation with development of neurodegeneration during the early stage of experimental stroke. Ischemic stroke model was induced by stereotaxic intracerebral injection of vasoconstricting agent endothelin-1 (ET-1). It was observed that neurodegeneration appears very early in that model and correlates well with migration of inflammatory lymphocytes and macrophages to the brain. Although the expression of several studied chemotactic cytokines (chemokines) was significantly increased at the early phase of ET-1 induced stroke model, no clear correlation of this expression with neurodegeneration was observed. These data may indicate that chemokines do not induce neurodegeneration directly. Upregulated in the ischemic brain chemokines may be a potential target for future therapies reducing inflammatory cell migration to the brain in early stroke. Inhibition of inflammatory cell accumulation in the brain at the early stage of stroke may lead to amelioration of ischemic neurodegeneration.

Topics: Animals; Brain; Brain Ischemia; Chemokine CCL2; Chemokine CCL3; Chemokine CCL5; Chemokine CXCL2; Chemokines; Endothelin-1; Enzyme-Linked Immunosorbent Assay; Female; Gene Expression Profiling; Gene Expression Regulation; Inflammation; Lymphocytes; Macrophages; Mice; Neurodegenerative Diseases; Real-Time Polymerase Chain Reaction; Stroke

The occurrence of stroke exhibits a strong circadian pattern with a peak in the morning hours after waking. The factors that influence this pattern of stroke prevalence may confer varying degrees of neuroprotection and therefore influence stroke severity. This question is difficult to address in clinical cases because of the variability in the location and duration of the ischemic event.. The purpose of this study was to determine if time of day affected the severity of stroke targeting the motor cortex in rats. Strokes were produced using topical application of the vasoconstrictor endothelin-1 to motor cortex of unanesthetized animals at 2 time points: early day and early night. Behavioral deficits were measured using reaching, cylinder, and horizontal ladder tasks, and the volume of the lesion was quantified.. Behavior on reaching and horizontal ladder tasks were both severely impaired by endothelin-1 treatment compared to vehicle-treated animals, but deficits did not differ according to time of treatment. Similarly, while endothelin-1 produced larger lesions of the motor cortex than did vehicle treatment, the size of the lesion did not differ according to time of treatment.. These results suggest that while many factors under circadian control can influence the prevalence of stroke, the magnitude of lesion and behavioral deficit resulting from an ischemic event may not be influenced by time of day.

Topics: Animals; Behavior, Animal; Brain Ischemia; Circadian Rhythm; Disease Models, Animal; Endothelin-1; Motor Activity; Motor Cortex; Rats; Rats, Long-Evans; Stroke; Time Factors

We explored whether the modulation of microglia activation with minocycline is beneficial to the therapeutic actions of bone marrow mononuclear cells (BMMCs) transplanted after experimental stroke. Male Wistar adult rats were divided in four experimental groups: ischemic control saline treated (G1, N = 6), ischemic minocycline treated (G2, N = 5), ischemic BMMC treated (G3, N = 5), and ischemic minocycline/BMMC treated (G4, N = 6). There was a significant reduction in the number of ED1+ cells in G3 animals (51.31 ± 2.41, P < 0.05), but this effect was more prominent following concomitant treatment with minocycline (G4 = 29.78 ± 1.56). There was conspicuous neuronal preservation in the brains of G4 animals (87.97 ± 4.27) compared with control group (G1 = 47.61 ± 2.25, P < 0.05). The behavioral tests showed better functional recovery in animals of G2, G3, and G4, compared with G1 and baseline (P < 0.05). The results suggest that a proper modulation of microglia activity may contribute to a more permissive ischemic environment contributing to increased neuroprotection and functional recovery following striatal ischemia.

Topics: Animals; Bone Marrow Cells; Bone Marrow Transplantation; Brain Ischemia; Cells, Cultured; Endothelin-1; Macrophage Activation; Macrophages; Male; Microglia; Minocycline; Neuroprotective Agents; Rats; Rats, Wistar; Recovery of Function; Stroke

Ischaemic stroke induces endothelial progenitor cell (EPC) mobilisation from bone marrow into peripheral blood. Circulating EPCs play an important role in post-injury regeneration of vasculature, whereas endothelial cells (ECs) have been shown to reflect endothelial damage and may be responsible for increased Endothelin-1 (ET-1) expression. We investigated herein the association between numbers of circulating ECs and EPCs, the levels of soluble factors regulating their migration and function, and the clinical outcome in patients with haemorrhagic (HS) or ischaemic stroke (IS). Sixteen patients with HS and eighteen with IS were assessed during the first 24h, day 3, and day 7 after stroke and compared them with twenty-three control subjects. We found elevated EPC and EC concentrations using flow cytometry and increase in VEGF, SDF-1, HGF, and ET-1 plasma levels by ELISA in the HS patients, while ET-1 mRNA expression in peripheral blood cells was elevated in the IS patients. Significant correlations were observed between EPCs or ECs and Big ET-1 protein or mRNA levels in HS but not in the IS patients. We suggest that ET-1 may play a role in pathophysiology of stroke and subsequent EPC mobilisation; however, further studies aimed at the precise elucidation of this issue are required.

Topics: Aged; Aged, 80 and over; Biomarkers; Brain Ischemia; Cerebral Hemorrhage; Endothelial Cells; Endothelin-1; Female; Humans; Male; Middle Aged; Stem Cells; Stroke; Up-Regulation

NKN reduces brain edema, neuronal death and neurological deficits in rats after cerebral ischemia. In the present study, we investigated whether NKN was effective on brain injury in cerebral ischemia rats.. The middle cerebral artery occlusion (MCAO) model was used to produce experimental cerebral ischemia in adult male Wistar rats. The activity of SOD and concentration of MDA were determined. We also examined the efficacy of NKN on neurological deficit scores, expression of N-methyl-D-aspartate receptor and endothelin-1 mRNA in brain of focal cerebral ischemia rats.. The results show that NKN significantly increased the activity of SOD, decreased the concentration of MDA, decreased neurological deficit scores, inhibited the expression of N-methyl-D-aspartate receptor and endothelin-1 mRNA in brain of focal cerebral ischemia rats.. The results implied NKN could protect brain against injury caused by cerebral ischemia.

Topics: Abietanes; Acetophenones; Animals; Benzoates; Brain Ischemia; Bridged-Ring Compounds; Drug Combinations; Endothelin-1; Glucosides; Immunohistochemistry; In Situ Hybridization; Infarction, Middle Cerebral Artery; Male; Malondialdehyde; Neurologic Examination; Neurons; Neuroprotective Agents; Pyrazines; Rats; Rats, Wistar; Receptors, N-Methyl-D-Aspartate; Stroke; Superoxide Dismutase

Endothelin (ET) receptor A antagonism decreases neuronal damage in experimental models of stroke. Since large arteries like basilar artery contribute significantly to total cerebrovascular resistance and are major determinants of microvascular pressure, dysregulation of basilar artery function may worsen stroke injury. ET-1 is involved in the regulation of basilar constriction. However, whether stroke influences vasoreactivity of basilar artery and to what extent ET-1 contributes to basilar vascular dysfunction after stroke remained unknown. The goal of this study was to test the hypothesis that ET-1 impairs basilar artery vasorelaxation after ischemia/reperfusion (I/R) injury via activation of ET(A) receptor.. Male Wistar rats were subjected to 3h middle cerebral artery occlusion (MCAO) and 21 h reperfusion. One group received ET(A) receptor antagonist atrasentan (5 mg/kg, i.p.) at reperfusion. At 24h, basilar arteries were isolated from control non-stroked, stroked and stroked+atrasentan-treated animals for vascular reactivity measurements using pressurized arteriograph.. Acetylcholine (Ach)-induced maximum relaxation (R(max)) was decreased in stroked animals as compared to non-stroked group and ET(A) antagonism partially restored it. There was also a trend for decreased EC(50) value for the antagonist treatment group indicating improved Ach sensitivity.. These findings suggest that I/R not only affects vessels distal to the occlusion but also impairs relaxation of proximal large vessels. ET-1-mediated basilar artery dysfunction may contribute to neurovascular damage after stroke and early restoration of vascular function by ET receptor antagonism after I/R injury may offer a therapeutic strategy.

Topics: Acetylcholine; Animals; Atrasentan; Basilar Artery; Brain Ischemia; Disease Models, Animal; Endothelin A Receptor Antagonists; Endothelin-1; Endothelium, Vascular; Male; Pyrrolidines; Rats; Rats, Wistar; Receptor, Endothelin A; Reperfusion Injury; Stroke; Vasodilation

This study was designed to investigate the relation between plasma von Willebrand factor (VWF) or endothelin-1 (ET-1) and post-carotid artery stenting (CAS) restenosis.. Plasma levels of VWF and ET-1 were measured in 61 patients (36 males, mean age 64.4 ± 6.8 years) before and after CAS. The mean follow-up time was 13.8 ± 1.7 months (range, 6-63). In-stent restenosis was defined as a >10% narrowing of the vascular lumen with or without ischemic symptoms following CAS.. In-stent restenosis was identified in 14 (23%) patients, including 3 with >50% restenosis. In the restenosis group, mean VWF and ET-1 levels at 2 weeks, 1 and 6 months after CAS were higher than the baseline levels (p < 0.05 or p < 0.01). Mean levels of VWF and ET-1 in the restenosis group were higher than in the non-restenosis group within 6 months after CAS (p < 0.05 or p < 0.01).. Persistent elevation in plasma VWF and ET-1 within the first 6 months of CAS was found in patients with in-stent restenosis.

Topics: Aged; Analysis of Variance; Biomarkers, Pharmacological; Coronary Restenosis; Coronary Vessels; Drug-Eluting Stents; Endothelin-1; Female; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Male; Middle Aged; Platelet Aggregation Inhibitors; Prognosis; Prospective Studies; Risk Assessment; Stroke; von Willebrand Factor

For successful translation to clinical stroke studies, the Stroke Therapy Academic Industry Round Table criteria have been proposed. Two important criteria are testing of therapeutic interventions in conscious animals and the presence of a co-morbidity factor. We chose to work with hypertensive rats since hypertension is an important modifiable risk factor for stroke and influences the clinical outcome. We aimed to compare the susceptibility to ischemia in hypertensive rats with those in normotensive controls in a rat model for induction of ischemic stroke in conscious animals.. The vasoconstrictor endothelin-1 was stereotactically applied in the vicinity of the middle cerebral artery of control Wistar Kyoto rats (WKYRs) and spontaneously hypertensive rats (SHRs) to induce a transient decrease in striatal blood flow, which was measured by the laser Doppler technique. Infarct size was assessed histologically by cresyl violet staining. Sensory-motor functions were measured at several time points using the neurological deficit score. Activation of microglia and astrocytes in the striatum and cortex was investigated by immunohistochemistry using antibodies against CD68/Iba-1 and glial fibrillary acidic protein.. The SHRs showed significantly larger infarct volumes and more pronounced sensory-motor deficits, compared to the WKYRs at 24 h after the insult. However, both differences disappeared between 24 and 72 h. In SHRs, microglia were less susceptible to activation by lipopolysaccharide and there was a reduced microglial activation after induction of ischemic stroke. These quantitative and qualitative differences may be relevant for studying the efficacy of new treatments for stroke in accordance to the Stroke Therapy Academic Industry Round Table criteria.

Topics: Animals; Brain Ischemia; Cerebral Cortex; Corpus Striatum; Down-Regulation; Endothelin-1; Genetic Predisposition to Disease; Hypertension; Lipopolysaccharides; Male; Microglia; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Stroke

Endothelin-1 (ET-1) is involved on the development of cerebral edema in acute ischemic stroke. As edema is a therapeutic target in cerebral ischemia, our aim was to study the effect of antagonists for ET-1 receptors (Clazosentan® and BQ-788, specific antagonists for receptors A and B, respectively) on the development of edema, infarct volume and sensorial-motor deficits in rats subjected to ischemia by occlusion of the middle cerebral artery (MCAO). We used Wistar rats (280-320 g) submitted to ischemia by intraluminal transient (90 min) MCAO. After ischemia, rats were randomized into 4 groups (n = 6) treated with; 1) control group (saline), 2) Clazosentan® group (10 mg/kg iv), 3) BQ-788 group (3 mg/kg iv), and 4) combined treatment (Clazosentan® 10 mg/kg plus BQ-788 3 mg/kg iv). We observed that rats treated with Clazosentan® showed a reduction of edema, measured by MRI, at 72 h (hours) and at day 7 (both p < 0.0001), and a decrease in the serum levels of ET-1 at 72 h (p < 0.0001) and at day 7 (p = 0.009). The combined treatment also induced a reduction of edema at 24 h (p = 0.004), 72 h (p < 0.0001) and at day 7 (p < 0.0001), a reduction on infarct volume, measured by MRI, at 24 and 72 h, and at day 7 (all p < 0.01), and a better sensorimotor recovery at 24 and 72 h, and at day 7 (all p < 0.01). Moreover, Clazosentan® induced a decrease in AQP4 expression, while BQ-788 induced an increase in AQP9 expression. These results suggest that antagonists for ET-1 receptors may be a good therapeutic target for cerebral ischemia.

Topics: Animals; Aquaporins; Blotting, Western; Brain Edema; Brain Ischemia; Dioxanes; Endothelin A Receptor Antagonists; Endothelin B Receptor Antagonists; Endothelin-1; Evoked Potentials, Somatosensory; Image Processing, Computer-Assisted; Infarction, Middle Cerebral Artery; Magnetic Resonance Imaging; Male; Nervous System Diseases; Neuroprotective Agents; Oligopeptides; Piperidines; Pyridines; Pyrimidines; Rats; Rats, Wistar; Stroke; Sulfonamides; Tetrazoles

The markers of regulation vascular tone, such as rennin, endothelin-1, and C-type natriuretic peptide, are of great value for prognosis of hemorrhagic transformation and fatal outcome of ischemic stroke. A change in the vascular tone in case of hemorrhagic transformation at the affected site precedes activation of the coagulation component of hemostasis as a mechanism preventing blood loss and increasing fibrinogen level. This work was aimed to study the balance of the above markers and fibrinogen in the prognosis of hemorrhagic transformation and fatal outcome in the acute period of ischemic stroke. It included 62 patients receiving no thrombolytic therapy. It was shown that symptomatic hemorrhagic transformation was associated with elevated rennin levels without a marked fall in the level of C-type natriuretic peptide and asymptomatic hemorrhagic transformation with elevated endothelin-1 levels and decreased concentration of natriuretic peptide. Fibrinogen level on day 4 of the observation proved to be a reliable predictor of negative prognosis. Asymptomatic hemorrhagic transformation without fatal outcome was associated with systemic and local vasoconstriction and inhibition of local vasodilation. Symptomatic hemorrhagic transformation with the fatal outcome was accompanied by dysregulation of vascular tone in the form of activation of systemic and local vasoconstriction, insufficient inhibition of local vasodilation and compensatory reaction in the form of activation of hemostatic mechanisms manifest as elevated fibrinogen levels on day 4. The lethal outcome without hemorrhagic transformation was associated with systemic vasoconstriction, activation of local vasodilation and vasoconstriction leading to local "biochemical paralysis" of vascular tone regulation.

Topics: Aged; Aged, 80 and over; Biomarkers; Blood Coagulation; Brain Ischemia; Cerebral Hemorrhage; Chymosin; Endothelin-1; Female; Fibrinogen; Humans; Male; Middle Aged; Natriuretic Peptide, C-Type; Predictive Value of Tests; Prognosis; Stroke; Survival Analysis; Vasomotor System

Whereas large injuries to the brain lead to considerable irreversible functional impairments, smaller strokes or traumatic lesions are often associated with good recovery. This recovery occurs spontaneously, and there is ample evidence from preclinical studies to suggest that adjacent undamaged areas (also known as peri-infarct regions) of the cortex 'take over' control of the disrupted functions. In rodents, sprouting of axons and dendrites has been observed in this region following stroke, while reduced inhibition from horizontal or callosal connections, or plastic changes in subcortical connections, could also occur. The exact mechanisms underlying functional recovery after small- to medium-sized strokes remain undetermined but are of utmost importance for understanding the human situation and for designing effective treatments and rehabilitation strategies. In the present study, we selectively destroyed large parts of the forelimb motor and premotor cortex of adult rats with an ischaemic injury. A behavioural test requiring highly skilled, cortically controlled forelimb movements showed that some animals recovered well from this lesion whereas others did not. To investigate the reasons behind these differences, we used anterograde and retrograde tracing techniques and intracortical microstimulation. Retrograde tracing from the cervical spinal cord showed a correlation between the number of cervically projecting corticospinal neurons present in the hindlimb sensory-motor cortex and good behavioural recovery. Anterograde tracing from the hindlimb sensory-motor cortex also showed a positive correlation between the degree of functional recovery and the sprouting of neurons from this region into the cervical spinal cord. Finally, intracortical microstimulation confirmed the positive correlation between rewiring of the hindlimb sensory-motor cortex and the degree of forelimb motor recovery. In conclusion, these experiments suggest that following stroke to the forelimb motor cortex, cells in the hindlimb sensory-motor area reorganize and become functionally connected to the cervical spinal cord. These new connections, probably in collaboration with surviving forelimb neurons and more complex indirect connections via the brainstem, play an important role for the recovery of cortically controlled behaviours like skilled forelimb reaching.

Topics: Animals; Disease Models, Animal; Electric Stimulation; Endothelin-1; Female; Forelimb; Hindlimb; Magnetic Resonance Imaging; Motor Cortex; Motor Skills; Nerve Regeneration; Neural Pathways; Neuroanatomical Tract-Tracing Techniques; Neuroimaging; Pyramidal Tracts; Rats; Rats, Long-Evans; Recovery of Function; Spinal Cord; Stroke

Ischemic stroke may initiate a reperfusion injury leading to brain damage cascades where inflammatory mechanisms play a major role. Therefore, the necessity for the novel stroke-protecting agents whose the mechanism of action is focused on their anti-inflammatory potency is still on the agenda for drug designers. Our previous studies demonstrated that cerebrocrast (a 1,4-dihydropyridine derivative) and mildronate (a representative of the aza-butyrobetaine class) possessed considerable anti-inflammatory and neuroprotective properties in different in vitro and in vivo model systems. The present study investigated their stroke-protecting ability in an endothelin-1 (ET-1)-induced ischemic stroke model in rats.. Male Wistar rats were pretreated (for 7 days, per os) with cerebrocrast (0.1 mg/kg), mildronate (100 mg/kg), or their combination, followed by the intracerebral injection of ET-1. Functional and behavioral tests were carried out up to 14 days after the ET-1 injection. Ex vivo, the number of degenerated neurons and the infarction size in the cerebral cortical tissue were assessed histologically.. Cerebrocrast and mildronate effectively normalized ET-1-induced disturbances in neurological status, improved the muscle tone, and decreased the number of degenerated cortical cells. Both drugs also reduced the infarction size, and cerebrocrast showed at least a 2-fold higher activity than mildronate. The combination of both drugs did not cause a more pronounced effect in comparison with the action of drugs administered separately.. The 1,4-dihydropyridine and aza-butyrobetaine structures may serve for the design of novel stroke-protecting agents to prevent severe neurological poststroke consequences.

Topics: Animals; Dihydropyridines; Disease Models, Animal; Drug Evaluation, Preclinical; Drug Therapy, Combination; Endothelin-1; Male; Methylhydrazines; Neuroprotective Agents; Rats; Rats, Wistar; Stroke

The effects of the halogenated aromatic amino acid 3,5-dibromo-D: -tyrosine (3,5-DBr-D: -Tyr) were studied in rat models of stroke and epileptic seizures caused by middle cerebral artery occlusion (MCAo) through respective intracerebral injection of endothelin-1 (ET-1) and intraperitoneal (i.p.) injection of pentylenetetrazole (PTZ). 3,5-DBr-D: -Tyr was administered as three bolus injections (30 or 90 mg/kg, i.p.) starting at 30, 90, and 180 min after ET-1 administration or as a single bolus (30 mg/kg, i.p.) 15 min prior to PTZ administration. Neurological deficits and infarct volume were estimated 3 days after ET-1 administration and seizure score was assessed during the first 20 min after PTZ administration. The safety of 3,5-DBr-D: -Tyr was evaluated in control animals using telemetry to measure cardiovascular parameters and immunostaining to assess the level of activated caspase-3. 3,5-DBr-D: -Tyr significantly improved neurological function and reduced infarct volume in the brain even when the treatment was initiated 3 h after the onset of MCAo. 3,5-DBr-D: -Tyr significantly depressed PTZ-induced seizures. 3,5-DBr-D: -Tyr did not cause significant changes in arterial blood pressure, heart rate and spontaneous locomotor activity, nor did it increase the number of activated caspase-3 positive cells in the brain. We conclude that 3,5-DBr-D: -Tyr, by alleviating the deleterious effects of MCAo and PTZ in rats with no obvious intrinsic effects on cardiovascular parameters and neurodegeneration, exhibits promising potential as a novel therapeutic direction for stroke and seizures.

Topics: Animals; Blood Pressure; Brain; Caspase 3; Disease Models, Animal; Endothelin-1; Epilepsy; Heart Rate; Hydrocarbons, Brominated; Infarction, Middle Cerebral Artery; Male; Motor Activity; Pentylenetetrazole; Rats; Rats, Sprague-Dawley; Severity of Illness Index; Stroke; Tyrosine

The nature of stress-related cognitive changes is still a matter of debate. Stress is often considered to be deleterious to cognitive function, despite many instances in which beneficial effects are evident in neural structure and cognition. Moreover, in some neuropathological conditions such as focal ischemia, stress exaggerates loss of cognitive function. The present experiments set out to investigate the effects of repeated restraint stress on spatial cognition in rats, and on recovery from a focal stroke induced by injection of endothelin-1 (ET-1) into the hippocampus (HPC). We did not observe a deleterious effect of stress on performance in the Morris water task (MWT). The HPC focal stroke induced by ET-1 produced lasting spatial learning impairments. Importantly, rats in the HPC stroke+stress group exhibited superior performance in the MWT compared with the HPC stroke-only group. No between-group structural difference was observed related to stress. These findings confirm that corticosterone-related experiences may be key factors influencing cognitive performance after HPC focal ischemic stroke.

Topics: Analysis of Variance; Animals; Endothelin-1; Hippocampus; Male; Maze Learning; Rats; Rats, Long-Evans; Restraint, Physical; Spatial Behavior; Stress, Physiological; Stress, Psychological; Stroke

Stress is one of the most important variables to determine recovery following stroke. We have previously reported that post-stroke exposure to either stress or corticosterone (CORT) alleviates hippocampal ischemic outcome. The present experiment expands previous findings by investigating the influence of exposure to stress prior to ischemic event. Rats received either daily restraint stress (1h/day; 16 consecutive days) or CORT (0.5mg/kg; 16 consecutive days) prior to focal ischemic stroke in the hippocampus induced by bilateral injection of endothelin-1 (ET-1). All experimental groups were then tested in the ziggurat task, a new task for spatial cognition. The stress+stroke group showed significant deficits in both hippocampal structure and function. No deleterious effect of pre-stroke exposure to CORT was found in the CORT+stroke group. Our results indicate that a history of chronic stress sensitizes hippocampal cells to the damaging consequences of focal ischemia. The opposing effects of CORT-related experiences in this study not only reflect the diversity of glucocorticoid actions in the stress response, but also provide evidence that elevated CORT in the absence of emotional disturbance is not sufficient to produce hippocampal deficit.

Topics: Animals; Chronic Disease; Corticosterone; Disease Models, Animal; Endothelin-1; Glucocorticoids; Hippocampus; Male; Maze Learning; Problem Solving; Rats; Rats, Long-Evans; Spatial Behavior; Stress, Physiological; Stroke; Time Factors

Topics: Brain Ischemia; C-Reactive Protein; Endothelin-1; Humans; Stroke

Activation of angiotensin-converting enzyme 2 (ACE2), production of angiotensin-(1-7) [Ang-(1-7)] and stimulation of the Ang-(1-7) receptor Mas exert beneficial actions in various peripheral cardiovascular diseases, largely through opposition of the deleterious effects of angiotensin II via its type 1 receptor. Here we considered the possibility that Ang-(1-7) may exert beneficial effects against CNS damage and neurological deficits produced by cerebral ischaemic stroke. We determined the effects of central administration of Ang-(1-7) or pharmacological activation of ACE2 on the cerebral damage and behavioural deficits elicited by endothelin-1 (ET-1)-induced middle cerebral artery occlusion (MCAO), a model of cerebral ischaemia. The results of the present study demonstrated that intracerebroventricular infusion of either Ang-(1-7) or an ACE2 activator, diminazine aceturate (DIZE), prior to and following ET-1-induced MCAO significantly attenuated the cerebral infarct size and neurological deficits measured 72 h after the insult. These beneficial actions of Ang-(1-7) and DIZE were reversed by co-intracerebroventricular administration of the Mas receptor inhibitor, A-779. Neither the Ang-(1-7) nor the DIZE treatments altered the reduction in cerebral blood flow elicited by ET-1. Lastly, intracerebroventricular administration of Ang-(1-7) significantly reduced the increase in inducible nitric oxide synthase mRNA expression within the cerebral infarct that occurs following ET-1-induced MCAO. This is the first demonstration of cerebroprotective properties of the ACE2-Ang-(1-7)-Mas axis during ischaemic stroke, and suggests that the mechanism of the Ang-(1-7) protective action includes blunting of inducible nitric oxide synthase expression.

Topics: Angiotensin I; Angiotensin II; Angiotensin-Converting Enzyme 2; Animals; Diminazene; Endothelin-1; Enzyme Activation; Infarction, Middle Cerebral Artery; Male; Nitric Oxide Synthase Type II; Peptide Fragments; Peptidyl-Dipeptidase A; Proto-Oncogene Mas; Proto-Oncogene Proteins; Rats; Rats, Sprague-Dawley; Receptors, G-Protein-Coupled; Stroke

SC1 is a member of the SPARC family of glycoproteins that regulate cell-matrix interactions in the developing brain. SC1 is expressed in astrocytes, but nothing is known about the expression in the aged or after stroke. We found that after focal striatal ischemic infarction in adult rats, SC1 increased in astrocytes surrounding the infarct and in the glial scar, but in aged rats, SC1 was lower at the lesion edge. Glial fibrillary acidic protein (GFAP) also increased, but it was less prominent in reactive astrocytes further from the lesion in the aged rats. On the basis of their differential expression of several molecules, 2 types of reactive astrocytes with differing spatiotemporal distributions were identified. On Days 3 and 7, SC1 was prevalent in cells expressing markers of classic reactive astrocytes (GFAP, vimentin, nestin, S100β), as well as apoliprotein E (ApoE), interleukin 1β, aggrecanase 1 (ADAMTS4), and heat shock protein 25 (Hsp25). Adjacent to the lesion on Days 1 and 3, astrocytes with low GFAP levels and a "starburst" SC1 pattern expressed S100β, ApoE, and Hsp32 but not vimentin, nestin, interleukin 1β, ADAMTS4, or Hsp25. Neither cell type was immunoreactive for NG2,CC-1, CD11b, or ionized calcium-binding adapter-1. Their differing expression of inflammation-related and putatively protective molecules suggests different roles for starburst and classic reactive astrocytes in the early glial responses to ischemia.

Topics: ADAM Proteins; ADAMTS5 Protein; Adenomatous Polyposis Coli Protein; Aging; Animals; Animals, Newborn; Apolipoprotein E4; Astrocytes; Brain; Calcium-Binding Proteins; CD11b Antigen; Cells, Cultured; Disease Models, Animal; Dose-Response Relationship, Drug; Endothelin-1; Extracellular Matrix Proteins; Functional Laterality; Gene Expression Regulation; Glial Fibrillary Acidic Protein; Gliosis; Heme Oxygenase (Decyclizing); Interleukin-1beta; Male; Nerve Tissue Proteins; Rats; Rats, Sprague-Dawley; Stroke; Time Factors; Vimentin

Stress has been linked to structural and functional outcomes after stroke. Moreover, the striatum, both dorsal and ventral, is a vital regulator of stress perception and associated physiological responses. This study investigates potential synergistic effects of focal stroke in the ventrolateral striatum and restraint stress on motor and spatial performance. Adult male Long-Evans rats were pre-trained in a skilled reaching task and randomly assigned to sham, stroke-only, stress-only and stroke+stress conditions. Ventrolateral striatal focal ischemia was induced by endothelin-1 (ET-1) infusion. Rats in stress-only and stroke+stress groups received 21 days of mild restraint stress after stroke. All rats were tested in the skilled reaching task and the ziggurat task (ZT) for post-stroke motor and spatial performance. There was no effect of ventrolateral striatal ischemia or stress alone on motor and spatial performance. Notably, stroke and stress interacted synergistically to reduce reaching success and to disrupt qualitative aspects of movement performance in the absence of histological differences in lesion size. Thus, stress can precipitate behavioural deficits after focal ischemia even in the absence of significant functional deficits on its own. These results emphasize the importance of prevention programmes to control post-stroke levels of stress in clinical populations.

Topics: Adrenal Cortex Hormones; Animals; Corpus Striatum; Endothelin-1; Male; Microinjections; Motor Activity; Rats; Rats, Long-Evans; Reaction Time; Restraint, Physical; Space Perception; Stress, Physiological; Stroke; Vasoconstrictor Agents

Concentrations of plasma vascular tone regulation markers that are indicators of endothelium dysfunction in the acute phase of ischemic stroke and their effect on the development of hemorrhagic transformation (HT) of the lesion focus have been studied. Concentrations of renin, endothelin 1-21, neuron-specific enolase, NT-proCNP, soluble adhesion molecules (sICAM) were measured in 67 patients on days 1, 3-4. Significantly higher concentrations of renin, endothelin 1-21, neuron-specific enolase were found in patients with HT in the first day compared to patients without HT. The level of NT-proCNP was lower in patients with HT; the increase in the severity of hemorrhagic component led to the elevation of neuron-specific enolase and sICAM concentrations. In conclusion, both markers of blood-brain barrier damage and regulating factors of vascular tone may play a predictive role in the development of HT in ischemic stroke.

Topics: Aged; Biomarkers; Blood-Brain Barrier; Cell Adhesion Molecules; Endothelin-1; Endothelium, Vascular; Female; Humans; Intracranial Hemorrhages; Male; Natriuretic Peptide, C-Type; Phosphopyruvate Hydratase; Renin; Stroke

Epidemiological literatures show an association between air pollution and ischemic stroke, and effective pollutants may include SO(2), NO(x), O(3), CO, and particulates. However, existing experimental studies lack evidence as to the presence of effects for SO(2), which has been the focus in developing countries with increasing use of coal as the main resource. In the present study, we treated Wistar rats with SO(2) at various concentrations and determined endothelin-1 (ET-1), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and intercellular adhesion molecule 1 (ICAM-1) messenger RNA (mRNA) and protein expression in the cortex. The results show that SO(2) elevated the levels of ET-1, iNOS, COX-2, and ICAM-1 mRNA and protein in a concentration-dependent manner. Then, we set up rat model of ischemic stroke using middle cerebral artery occlusion (MCAO) and further treated the model rats with filtered air and lower concentration SO(2) for the same period. As expected, elevated expression of ET-1, iNOS, COX-2, and ICAM-1 occurred in the cortex of MCAO model rats exposed to filtered air, followed by increased activation of caspase-3 and cerebral infarct volume. Interestingly, SO(2) inhalation after MCAO significantly amplified above effects. It implies that SO(2) inhalation caused brain injuries similar to that of cerebral ischemia, and its exposure in atmospheric environment contributed to the development and progression of ischemic stroke.

Topics: Air Pollutants; Animals; Cyclooxygenase 2; Disease Models, Animal; Disease Progression; Endothelin-1; Gene Expression; Infarction, Middle Cerebral Artery; Inhalation Exposure; Intercellular Adhesion Molecule-1; Male; Nitric Oxide Synthase Type II; Rats; Rats, Wistar; RNA, Messenger; Stroke; Sulfur Dioxide

Clinical data has shown that stroke exacerbates dementia in Alzheimer's disease (AD) patients. Previous work, combining rat models of AD and stroke have shown that neuroinflammation may be the common mediator between AD and stroke toxicity. This study examined the effects of triflusal (2-acetoxy-4-trifluoromethylbenzoic acid) in APP(23) transgenic mice receiving strokes. Six month-old APP(23) mice over-expressing mutant human amyloid precursor protein (APP) were used to model AD in this study. Unilateral injections of a potent vasoconstrictor, endothelin-1, into the striatum were used to mimic small lacunar infarcts. Immunohistochemical analysis was performed to examine AD-like pathology and inflammatory correlates of stroke and AD. APP(23) mice showed increases in AD-like pathology and inflammatory markers of AD in the cortex and hippocampus. Endothelin-induced ischemia triggered an inflammatory response along with increases in AD pathological markers in the region of the infarct. Triflusal reduced inflammation surrounding the endothelin-induced infarct only. At the dose used, anti-inflammatory treatment may be beneficial in reducing the AD and inflammatory correlates of stroke in a combined AD-stroke mouse model.

Topics: Administration, Oral; Alzheimer Disease; Amyloid beta-Protein Precursor; Animals; Antigens, CD; Brain Ischemia; Disease Models, Animal; Endothelin-1; Humans; Inflammation; Mice; Mice, Inbred C57BL; Mice, Transgenic; NF-kappa B; Platelet Aggregation Inhibitors; Salicylates; Stroke; tau Proteins; Tumor Necrosis Factor-alpha

Endothelins (ETs) are potent vasoconstrictor and may play a role in the pathophysiology of several cardiovascular diseases. Endothelin-mediated vasoconstriction may enhance ischemic neuronal damage. The study aimed to find out whether the plasma ET-1 levels may serve as marker of early ischemic stroke. Plasma ET-1 levels were tested in 20 patients with acute ischemic stroke, mean age 63.7 +/- 5.03 years, 12 men and 8 women, within 24 hours of stroke onset as compared to 10 sex- and age-matched control subjects; only the patients with normal CT-scan at admission were included in the study. Plasma ET-1 was measured by ELISA. The results were statistically analyzed by Student test and a p < 0.05 (95% CI) was considered statistically significant. ET-1 levels in patients with hemiplegia and normal CT-scan at admission were significantly higher as compared to control group (0.0910 +/- 0.0256 pg/mL vs. 0.0490 +/- 0.0185 pg/mL, p < 0.0001) (95% CI). Ischemic stroke is associated with acute and marked increased levels of ET-1 in plasma. This may reflect enhanced production by damaged endothelial cells within the infarcted lesion. ET-1 may be used as additional marker of cerebral ischemia in selected cases to distinguish between the onset of an ischemic stroke and other non-vascular diseases presenting similar symptoms.

Topics: Aged; Biomarkers; Brain Ischemia; Case-Control Studies; Endothelin-1; Female; Humans; Male; Middle Aged; Stroke

A vagus nerve-mediated, efferent cholinergic protective pathway activated by melanocortins is operative in circulatory shock and myocardial ischemia. Moreover, melanocortins have neuroprotective effects against brain damage after ischemic stroke. Here we investigated cerebral and systemic pathophysiologic reactions to focal cerebral ischemia in rats induced by intrastriatal microinjection of endothelin-1, and the possible protective role of the melanocortin-activated vagal cholinergic pathway. In the striatum and liver of saline-treated control rats, the activation of extracellular signal-regulated kinases, c-jun N-terminal kinases, and caspase-3, the increase in tumor necrosis factor-alpha (TNF-alpha) concentration and DNA fragmentation, as well as the increase in TNF-alpha plasma levels, occurred 10 and 20 h after the ischemic insult suggesting an activation of inflammatory and apoptotic responses. Treatment with [Nle(4), D-Phe(7)]alpha-melanocyte-stimulating hormone (NDP-alpha-MSH; 3 or 9 h after stroke) suppressed the inflammatory and apoptotic cascades at central and peripheral level. Bilateral vagotomy and pharmacologic blockade of peripheral nicotinic acetylcholine receptors blunted the protective effect of NDP-alpha-MSH. The present results show that focal brain ischemia in rats causes significant effects not only in the brain, but also in the liver. Moreover, our data support the hypothesis that a protective, melanocortin-activated, vagal cholinergic pathway is likely operative in conditions of ischemic stroke.

Topics: alpha-MSH; Animals; Apoptosis; Blotting, Western; Brain Ischemia; Corpus Striatum; DNA Fragmentation; Endothelin-1; Liver; Male; Rats; Rats, Wistar; Receptors, Nicotinic; Stroke; Tumor Necrosis Factor-alpha; Vagotomy; Vagus Nerve

An increased blood pressure can elicit remodeling of the cardiovascular system. Experimental data have implicated gp130, a subunit of the receptor for interleukin-6 (IL-6)-related cytokines, in the regulation of proliferation and apoptosis of cardiomyocytes and vascular smooth muscle cells (VSMC). Here, we investigate whether serum soluble gp130 concentrations correlate with blood pressure in humans, whether gp130 expression in the aorta differs between hypertensive and control rats, and whether angiotensin II or endothelin regulate gp130 expression in human VSMC.. We measured serum concentrations of soluble gp130, IL-6, the soluble IL-6 receptor, and the intima-media thickness of the common carotid artery in stroke patients (n = 48) and in elderly controls (n = 48). Furthermore, soluble gp130 levels were measured in young controls (n = 200). Expression of gp130 in Wistar-Kyoto (n = 12), spontaneously hypertensive rats (n = 12), and human VSMC was detected by real-time reverse transcription-PCR and immunohistochemistry.. Soluble gp130 serum concentrations correlated with blood pressure in stroke patients and in elderly and young controls and with the intima-media thickness of the common carotid artery in stroke patients. The hypothesis that elevated soluble gp130 derives from the vascular system was supported by the enhanced expression of gp130 in the aortic wall of spontaneously hypertensive rats. Furthermore, treatment of human VSMC with angiotensin II stimulated gp130 expression.. Our data suggest that soluble gp130 serum concentrations are correlated with blood pressure and may reflect vascular remodeling in response to arterial hypertension.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Angiotensin II; Animals; Aorta, Abdominal; Aorta, Thoracic; Benzimidazoles; Benzoates; Blood Pressure; Blood Pressure Determination; Carotid Arteries; Case-Control Studies; Cell Culture Techniques; Cells, Cultured; Cytokine Receptor gp130; Endothelin-1; Female; Gene Expression; Heart Rate; Humans; Immunohistochemistry; Male; Middle Aged; Muscle, Smooth, Vascular; Rats; Rats, Inbred SHR; Rats, Inbred WKY; RNA, Messenger; Species Specificity; Stroke; Telemetry; Telmisartan; Time Factors; Tunica Intima; Tunica Media; Vasoconstrictor Agents; Young Adult

The total saponins of Panax notoginseng have been clinically used for the treatment of cardiovascular diseases and stroke in China. Our recent study has identified ginsenoside-Rd, a purified component of total saponins of P. notoginseng, as an inhibitor to remarkably inhibit voltage-independent Ca(2+) entry. We deduced a hypothesis that the inhibition of voltage-independent Ca(2+) entry might contribute to its cerebrovascular benefits. Ginsenoside-Rd was administered to two-kidney, two-clip (2k2c) stroke-prone hypertensive rats to examine its effects on blood pressure, cerebrovascular remodeling and Ca(2+) entry in freshly isolated basilar arterial vascular smooth muscle cells (BAVSMCs). Its effects on endothelin-1 induced Ca(2+) entry and cellular proliferation were assessed in cultured BAVSMCs. The results showed that, in vivo, ginsenoside-Rd treatment attenuated basilar hypertrophic inward remodeling in 2k2c hypertensive rats without affecting systemic blood pressure.During the development of hypertension, there were time-dependent increases in receptor-operated Ca(2+) channel (ROCC)-, store-operated Ca(2+) channel (SOCC)- and voltage dependent Ca(2+) channel (VDCC)-mediated Ca(2+) entries in freshly isolated BAVSMCs. Ginsenoside-Rd reversed the increase in SOCC- or ROCC- but not VDCC-mediated Ca(2+) entry. In vitro, ginsenoside-Rd concentration-dependently inhibited endothelin-1 induced BAVSMC proliferation and Mn(2+) quenching rate within the same concentration range as required for inhibition of increased SOCC- or ROCC-mediated Ca(2+) entries during hypertension. These results provide in vivo evidence showing attenuation of hypertensive cerebrovascular remodeling after ginsenoside-Rd treatment. The underlying mechanism might be associated with inhibitory effects of ginsenoside-Rd on voltage-independent Ca(2+) entry and BAVSMC proliferation, but not with VDCC-mediated Ca(2+) entry.

Topics: Animals; Basilar Artery; Blood Pressure; Brain; Calcium; Calcium Channel Blockers; Cell Proliferation; Electric Conductivity; Endothelin-1; Ginsenosides; Hypertension, Renovascular; Male; Microscopy, Electron, Transmission; Muscle, Smooth, Vascular; Rats; Rats, Sprague-Dawley; Stroke

Endogenous levels of angiotensin II (Ang II) are increased in the cortex and hypothalamus following stroke, and Ang II type 1 receptor blockers (ARBs) have been shown to attenuate the deleterious effects in animal stroke models using middle cerebral artery (MCA) intraluminal occlusion procedures. However, the endothelin-1 (ET-1)-induced middle cerebral artery occlusion (MCAO) model of cerebral ischaemia is thought to more closely mimic the temporal events of an embolic stroke. This method provides rapid occlusion of the MCA and a gradual reperfusion that lasts for 16-22 h. The aim of the present study was to evaluate whether systemic administration of an ARB prior to ET-1-induced MCAO would provide cerebroprotection during this model of ischaemic stroke. Injection of 3 microl of 80 microM ET-1 adjacent to the MCA resulted in complete occlusion of the vessel that resolved over a period of 30-40 min. Following ET-1-inducedMCAO, rats had significant neurological impairment, as well as an infarct that consisted of 30% of the ipsilateral grey matter. Systemic pretreatment with 0.2 mg kg(-1) day(-1) candesartan for 7 days attenuated both the infarct size and the neurological deficits caused by ET-1-induced MCAO without altering blood pressure. This study confirms the cerebroprotective properties of ARBs during ischaemic stroke and validates the ET-1-induced MCAO model for examination of the role of the brain renin-angiotensin system in ischaemic stroke.

Topics: Angiotensin II Type 1 Receptor Blockers; Animals; Benzimidazoles; Biphenyl Compounds; Brain Ischemia; Cerebral Infarction; Disease Models, Animal; Endothelin-1; Infarction, Middle Cerebral Artery; Male; Rats; Rats, Sprague-Dawley; Stroke; Tetrazoles

Subcortical white matter stroke is a common stroke subtype but has had limited pre-clinical modeling. Recapitulating this disease process in mice has been impeded by the relative inaccessibility of the subcortical white matter arterial supply to induce white matter ischemia in isolation. In this report, we detail a subcortical white matter stroke model developed in the mouse and its characterization with a comprehensive set of MRI, immunohistochemical, neuronal tract tracing and electron microscopic studies. Focal injection of the vasoconstrictor endothelin-1 into the subcortical white matter produces an infarct core that develops a maximal MRI signal by day 2, which is comparable in relative size and location to human subcortical stroke. Immunohistochemical studies indicate that oligodendrocyte apoptosis is maximal at day 1 and apoptotic cells extend away from the stroke core into the peri-infarct white matter. The amount of myelin loss exceeds axonal fiber loss in this peri-infarct region. Activation of microglia/macrophages takes place at 1 day after injection near injured axons. Neuronal tract tracing demonstrates that subcortical white matter stroke disconnects a large region of bilateral sensorimotor cortex. There is a robust glial response after stroke by BrdU pulse-labeling, and oligodendrocyte precursor cells are initiated to proliferate and differentiate within the first week of injury. These results demonstrate the utility of the endothelin-1 mediated subcortical stroke in the mouse to study post-stroke repair mechanisms, as the infarct core extends through the partially damaged peri-infarct white matter and induces an early glial progenitor response.

Topics: Animals; Apoptosis; Cell Proliferation; Dementia, Vascular; Disease Models, Animal; Endothelin-1; Gliosis; Macrophages; Magnetic Resonance Imaging; Male; Mice; Mice, Inbred C57BL; Myelin Sheath; Nerve Fibers, Myelinated; Nerve Regeneration; Neural Pathways; Oligodendroglia; Recovery of Function; Stem Cells; Stroke; Vasoconstrictor Agents; Wallerian Degeneration

When locally infused, the potent vasoconstrictor, endothelin-1 (ET-1) produces partial ischemic damage in many regions of the brain, including the hippocampus. The hippocampus is known for a high density of glucocorticoid receptors and for the potent actions of stress and corticosterone to modulate function. The current experiment evaluates the effects of stress and corticosterone on the severity of memory impairment and anatomical pathology produced by hippocampal mini-stroke. Rats with ET-1-induced mini-stroke were exposed to mild restraint stress (1 h/day) or oral corticosterone (0.5 mg/kg) for 16 consecutive days. Spatial memory was then tested in the Morris water task (MWT) and the ziggurat task (ZT). The groups ET-1+stress and ET-1+corticosterone performed significantly better in both tasks than the ET-1-only group. This suggests that increasing corticosteroid levels alleviates the hippocampal stroke-induced memory deficits. Hippocampal volumetric assessment also revealed that both the post-stroke stress and corticosteroid treatment significantly decreased the volume of hippocampal damage. The findings support the view that elevated levels of corticosterone may exert neuroprotective effects in the hippocampus following stroke.

Topics: Animals; Cognition; Corticosterone; Endothelin-1; Hippocampus; Male; Memory; Rats; Rats, Long-Evans; Restraint, Physical; Stress, Psychological; Stroke

Migraine with aura is a risk factor for ischemic stroke, but the mechanism by which these disorders are associated remains unclear. Both disorders exhibit familial clustering, which may imply a genetic influence on migraine and stroke risk. Genes encoding for endothelial function are promising candidate genes for migraine and stroke susceptibility because of the importance of endothelial function in regulating vascular tone and cerebral blood flow.. Using data from the Stroke Prevention in Young Women study, a population-based case-control study including 297 women aged 15 to 49 years with ischemic stroke and 422 women without stroke, we evaluated whether polymorphisms in genes regulating endothelial function, including endothelin-1 (EDN), endothelin receptor type B (EDNRB), and nitric oxide synthase-3 (NOS3), confer susceptibility to migraine and stroke.. EDN SNP rs1800542 and rs10478723 were associated with increased stroke susceptibility in whites (OR, 2.1; 95% CI, 1.1-4.2 and OR, 2.2; 95% CI, 1.1-4.4; P=0.02 and 0.02, respectively), as were EDNRB SNP rs4885493 and rs10507875, (OR, 1.7; 95% CI, 1.1-2.7 and OR, 2.4; 95% CI, 1.4-4.3; P=0.01 and 0.002, respectively). Only 1 of the tested SNP (NOS3 rs3918166) was associated with both migraine and stroke.. In our study population, variants in EDN and EDNRB were associated with stroke susceptibility in white but not in black women. We found no evidence that these genes mediate the association between migraine and stroke.

Topics: Adolescent; Adult; Black People; Case-Control Studies; Cohort Studies; DNA Mutational Analysis; Endothelin-1; Endothelium, Vascular; Female; Genetic Predisposition to Disease; Genetic Testing; Genotype; Humans; Middle Aged; Migraine Disorders; Mutation; Nitric Oxide Synthase Type III; Polymorphism, Genetic; Polymorphism, Single Nucleotide; Receptor, Endothelin B; Stroke; White People; Young Adult

Abnormal glutamatergic activity is implicated in neurologic and neuropsychiatric disorders. Selective glutamate receptor antagonists were highly effective in animal models of stroke and seizures but failed in further clinical development because of serious side effects, including an almost complete set of symptoms of schizophrenia. Therefore, the novel polyvalent glutamatergic agent 3,5-dibromo-L-phenylalanine (3,5-DBr-L-Phe) was studied in rat models of stroke, seizures and sensorimotor gating deficit.. 3,5-DBr-L-Phe was administered intraperitoneally as three boluses after intracerebral injection of endothelin-1 (ET-1) adjacent to the middle cerebral artery to cause brain injury (a model of stroke). 3,5-DBr-L-Phe was also given as a single bolus prior to pentylenetetrazole (PTZ) injection to induce seizures or prior to the administration of the N-methyl-D-aspartate (NMDA) receptor antagonist dizocilpine (MK-801) to cause disruption of prepulse inhibition (PPI) of startle (sensorimotor gating deficit).. Brain damage caused by ET-1 was reduced by 52%, which is comparable with the effects of MK-801 in this model as reported by others. 3,5-DBr-L-Phe significantly reduced seizures induced by PTZ without the significant effects on arterial blood pressure and heart rate normally caused by NMDA antagonists. 3,5-DBr-L-Phe prevented the disruption of PPI measured 3 days after the administration of ET-1. 3,5-DBr-L-Phe also eliminated sensorimotor gating deficit caused by MK-801.. The pharmacological profile of 3,5-DBr-L-Phe might be beneficial not only for developing a therapy for the neurological and cognitive symptoms of stroke and seizures but also for some neuropsychiatric disorders.

Topics: Animals; Disease Models, Animal; Dizocilpine Maleate; Endothelin-1; Gait Disorders, Neurologic; Glutamic Acid; Male; Pentylenetetrazole; Phenylalanine; Rats; Rats, Sprague-Dawley; Reflex, Startle; Seizures; Stroke

This series of experiments represents a test of a theory concerning the etiology of age-related cognitive decline, including Alzheimer's disease (AD). The theory suggests that multiple combinations of cofactors produce variants of these disorders. Two factors that have been linked to the etiology of AD, that are of interest to our laboratories, are stress and vascular strokes. The current experiments tested the cofactors theory by evaluating the neuronal and functional effects of localized subthreshold strokes in the hippocampus of different groups of rats. One group experienced episodes of stress prior to stroke induction while the other did not. The results showed that a low dose of endothelin-1 (ET-1) injected into the hippocampus of groups of rats that had previously experienced stressful episodes showed enhanced hippocampal cell death and neurodegeneration that did not occur in the rats that did not experience stress prior to stroke induction. The results also showed that the stressed rats given subthreshold ET-1 injections into the hippocampus showed hippocampal-based learning and memory deficits that were not present in the non-stressed group given the same injections. This pattern of results suggests that individuals that are under stress are more vulnerable to insults to the hippocampus that have little effect on an individual that is not stressed. This vulnerability might be due to the actions of stress hormones, like the glucocorticoids, that have been previously shown to endanger hippocampal neurons.

Topics: Animals; Behavior, Animal; Cell Death; Cognition Disorders; Corticosterone; Endothelin-1; Hippocampus; Immunohistochemistry; Male; Nerve Degeneration; Rats; Rats, Long-Evans; Stress, Psychological; Stroke

Severe cerebral edema is associated with poor outcome in patients with acute stroke. Experimental studies suggest that astrocytic endothelin-1 (ET-1) has deleterious effects on water homeostasis, cerebral edema, and blood brain barrier (BBB) integrity, which contribute to more severe ischemic brain injury. In this study we analyze the association between high serum levels of ET-1 and the development of severe cerebral edema in patients treated with t-PA.. One hundred thirty-four patients treated with t-PA according SITS-MOST (Safe Implementation of Thrombolysis in Stroke Monitoring Study) criteria were prospectively studied. Serum levels of ET-1, matrix metalloproteinase-9 (MMP-9), and cellular fibronectin (c-Fn) were determined by ELISA in serum samples obtained on admission, before t-PA bolus. Severe brain edema was diagnosed if extensive swelling caused any shifting of the structures of the midline was detected on the cranial CT performed at 24 to 36 hours. Stroke severity was evaluated before t-PA administration and at 24 hours by NIHSS. Functional outcome at 3 months was evaluated by the modified Rankin Scale (mRS).. Nineteen patients (14.2%) developed severe brain edema. Median ET-1 (8.4 [6.7, 9.6] versus 1.9 [1.6, 3.2] fmol/mL, P<0.0001) and c-Fn (6.0 [4.1, 6.7] versus 3.2 [2.1, 4.6] mg/L, P<0.0001) serum levels were significantly higher in patients with severe cerebral edema. The best cut-off values for ET-1 and c-Fn serum levels for the prediction of severe brain edema were 5.5 fmol/mL (sensitivity 95% and specificity 94%) and 4.5 mg/L (sensitivity 73% and specificity 77%) respectively. ET-1 serum levels >5.5 fmol/mL before t-PA treatment were independently associated with development of severe brain edema (OR, 139.7; CI95%, 19.3 to 1012.2; P<0.0001), after adjustment for baseline stroke severity, early CT signs of infarction, serum levels of cFn >4.5 mg/L, and cardioembolic stroke subtype.. ET-1 serum levels >5.5 fmol/mL are associated with severe brain edema in acute stroke patients treated with t-PA. These results suggest that ET-1 may be a new diagnostic marker for development of severe brain edema in patients with acute ischemic stroke treated with t-PA.

Topics: Aged; Brain Edema; Brain Ischemia; Endothelin-1; Enzyme-Linked Immunosorbent Assay; Female; Fibronectins; Humans; Male; Matrix Metalloproteinase 9; Middle Aged; Odds Ratio; Stroke; Thrombolytic Therapy; Tissue Plasminogen Activator

Oxidative stress contributes to the progression of brain injury following ischemic stroke and reperfusion. NADPH oxidase is a well-established source of superoxide in vascular disease, but its contribution to tissue injury following ischemic stroke has yet to be fully elucidated. Here we show the spatiotemporal profile of NADPH oxidase subunits Nox2 and Nox4 and concurrent superoxide generation following stroke induced by middle cerebral artery constriction in conscious rats. Nox2 mRNA was progressively up-regulated in both the ipsilateral cortex and the striatum from 6 hr to 7 days poststroke and reperfusion. Nox4 mRNA was also up-regulated transiently in the cortex at 6 hr poststroke but returned to control levels after this time. In situ detection of superoxide generation with dihydroethidium fluorescence revealed an increase in superoxide within the ischemic core at 6 hr poststroke that was mostly colocalized with the neuronal marker NeuN. By 24 hr, this increase in superoxide production had spread to the boundary zone of the infarct, whereas it disappeared in the ischemic core as neuronal numbers declined. Subsequently, superoxide within the ischemic core again increased at 7 days and was mostly colocalized with the activated microglia/macrophage marker OX-42. Immunoreactivity to Nox2 followed the same spatiotemporal pattern as that of OX-42 immunostaining poststroke. Clearly, NADPH oxidase is an important mediator of oxidative stress and contributes to the progression of brain damage beyond the infarct core, via the activation of two catalytic subunits, Nox2 and Nox4. Selectively blocking these subunits might be useful for intervening in the progression of stroke brain injury.

Topics: Animals; Brain; Consciousness; Endothelin-1; Image Processing, Computer-Assisted; Immunohistochemistry; Male; Membrane Glycoproteins; NADPH Oxidase 2; NADPH Oxidase 4; NADPH Oxidases; Oxidative Stress; Rats; Rats, Wistar; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Stroke; Superoxides; Up-Regulation

To determine levels of vascular cellular adhesion molecule (VCAM)-1 and endothelin (ET)-1 in patients with stroke.. Thirty-four patients were prospectively studied. Plasma levels of VCAM-1 and ET-1 were measured by ELISA within 72 h of the event, at 7 and 90 days.. Levels of VCAM-1 increased overtime, whereas ET-1 values were initially and persistently elevated.. Increased circulating levels of VCAM-1 and ET-1 are present during stroke.

Topics: Aged; Biomarkers; Brain Ischemia; Endothelin-1; Female; Humans; Longitudinal Studies; Male; Middle Aged; Prospective Studies; Stroke; Vascular Cell Adhesion Molecule-1

Stroke-prone spontaneously hypertensive rats (SHRSP) often suffer from spontaneous stroke, in part, due to abnormalities in the cerebrovasculature. Here, we investigate the profile of key angiogenic factors and their basic signaling molecules in the brain of SHRSP during the age-dependent stages of hypertension. The profile of VEGF and its receptor, Flk-1, was dependent on age and stage of hypertension (i.e., down regulated at pre-hypertensive and malignant hypertensive stages, but up regulated at typical hypertensive stage), while that of its downstream components, pAkt and eNOS, were down regulated in a time-dependent manner in the frontal cortex of SHRSP compared to age-matched genetic control, normotensive WKY rats. On the other hand, the expression of endothelin-1 and its type A receptor (endothelin ETA receptor) were up regulated, depending on age and stage of hypertension. In contrast, levels of endothelin type B receptor were down regulated. The regional cerebral blood flow decreased during the development of malignant hypertension. Thus, subsequent experiments were designed to investigate whether endothelin-1 receptor antagonism, using endothelin-A/-B dual receptor antagonist SB209670, could normalize the molecular profile of these factors in SHRSP brain. Interestingly, blockage of endothelin-1 receptor restored to normal, levels of cerebral endothelin-1, endothelin ETA receptor and endothelin ETB receptor; VEGF and Flk-1; endothelial nitric oxide synthase (eNOS) and pAkt, in SHRSP, compared to age-matched WKY. Endothelin receptor blocker might be important to prevent the progression in the defect in VEGF and its angiogenic signaling cascade in the pathogenesis of hypertension-induced vascular remodeling in frontal cortex of SHRSP rats.

Topics: Animals; Blood Pressure; Brain; Cerebrovascular Circulation; Endothelin Receptor Antagonists; Endothelin-1; Hypertension; Indans; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Receptors, Endothelin; Signal Transduction; Stroke; Vascular Endothelial Growth Factor A

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

The aim was to test the hypothesis that occlusion of the middle cerebral artery (MCA) results in the development of epilepsy in rats. Further, we investigated whether lesion volume, hippocampal pathology, early seizures, or severity of behavioral impairment is associated with the development and severity of epilepsy or interictal spiking. MCA occlusion was induced by intracerebral injection of endothelin-1 (ET; 120 pmol). One group of ET-injected rats were followed-up for 6 months (n = 15) and another for 12 months (n = 20). Sham-operated animals were injected with saline (n = 12). Occurrence of early and late seizures was monitored by intermittent video-electroencephalography. Sensorimotor function was tested with the running wheel and tapered beam-walking tests. Emotional learning and memory were assessed with the fear conditioning test and spatial learning and memory with the Morris water maze. Finally, brains were processed for histology. Only one rat developed late spontaneous seizures (i.e., epilepsy). Epileptiform interictal spiking was detected in 9 of 26 animals. Early seizures did not predict the development of epilepsy, spiking activity, or severity of behavioral impairment. Production of MCA stroke by intracerebral injection of ET was not a strong trigger of epileptogenesis in adult rats. Further studies are needed to investigate the effect of age, genetic background, and location of ET-injection on the development of hyperexcitability and the risk of post-stroke epileptogenesis.

Topics: Animals; Behavior, Animal; Cerebrovascular Disorders; Conditioning, Psychological; Electrodes, Implanted; Electroencephalography; Endothelin-1; Epilepsy; Follow-Up Studies; Hippocampus; Male; Maze Learning; Middle Cerebral Artery; Rats; Rats, Sprague-Dawley; Seizures; Stroke; Video Recording

Hypertension frequently occurs in obese subjects. It has been reported that leptin and resistin induce endothelin-1 expression in vascular endothelial cells. Altered function of brain microvascular endothelial cells may be related to increased occurrences of stroke in hypertensive patients. In the present study, we therefore studied the effects of leptin and resistin on the expression of endothelin-1 and adrenomedullin in bovine brain microvascular endothelial cells. Northern blot analysis showed that leptin (10(-10)-10(-8) mol/l), resistin (10(-10)-10(-8) mol/l) or a combination of leptin and resistin (10(-8) mol/l for each) had no significant effects on the expression of endothelin-1 mRNA or adrenomedullin mRNA in cultured bovine brain microvascular endothelial cells. On the other hand, hypoxia induced, and tumor necrosis factor-alpha (10 ng/ml) decreased, the expression levels of endothelin-1 and adrenomedullin mRNAs, indicating that the bovine brain microvascular endothelial cells were able to respond to hypoxia and tumor necrosis factor-alpha. Consistent with the results of Northern blot analysis, immunoreactive endothelin and immunoreactive adrenomedullin concentrations in the medium were not significantly changed by the treatment with leptin, resistin, or a combination of leptin and resistin. The present study thus showed that neither leptin nor resistin affects the expression of endothelin-1 or adrenomedullin in bovine brain microvascular endothelial cells.

Topics: Adrenomedullin; Animals; Brain; Cattle; Cells, Cultured; Endothelin-1; Endothelium, Vascular; Gene Expression Regulation; Hypertension; Hypoxia; Leptin; Microcirculation; Peptides; Resistin; RNA, Messenger; Stroke; Tumor Necrosis Factor-alpha

Stroke represents one of the leading causes of death and disability in Western countries, but despite intense research, only few options exist for the treatment of stroke-related infarction of brain tissue. In experimental stroke, cell therapy can partly reverse some behavioural deficits. However, the underlying mechanisms have remained unknown as most studies revealed only little, if any, evidence for neuronal replacement and the observed behavioural improvements appeared to be related rather to a graft-derived induction of a positive response in the remaining host tissue than to cell replacement by the graft itself. The present study was performed to test a murine embryonic stem cell (ESC)-based approach in rats subjected to endothelin-induced middle cerebral artery occlusion. Efficacy of cell therapy regarding graft survival, neuronal yield and diversity, and electrophysiological features of the grafted cells were tested after transplanting ESC-derived neural precursors into the infarct core and periphery of adult rats. Here, we show that grafted cells can survive, albeit not entirely, most probably as a consequence of an ongoing immune response, within the infarct core for up to 12 weeks after transplantation and that they differentiate with high yield into immunohistochemically mature glial cells and neurons of diverse neurotransmitter-subtypes. Most importantly, transplanted cells demonstrate characteristics of electrophysiologically functional neurons with voltage-gated sodium currents that enable these cells to fire action potentials. Additionally, during the first 7 weeks after transplantation we observed spontaneous excitatory post-synaptic currents in graft-derived cells indicating synaptic input. Thus, our observations show that ESC-based regenerative approaches may be successful in an acutely necrotic cellular environment.

Topics: Animals; Brain Ischemia; Cell Differentiation; Cell Division; Cell Movement; Cell Survival; Embryonic Stem Cells; Endothelin-1; Immunohistochemistry; Infarction, Middle Cerebral Artery; Male; Membrane Potentials; Neurons; Patch-Clamp Techniques; Rats; Rats, Inbred F344; Stroke

This study investigated the effect of amphetamine (AMP) on skilled forelimb use following focal cortical ischaemic lesions in the rat. Unilateral lesions were produced by a novel method of intracortical microinjection of endothelin-1 (ET-1), intended to principally target the forelimb representation zone in primary motor-primary somatosensory cortex. Lesions were placed in the hemisphere contralateral to the preferred limb and produced deficits in skilled forelimb use on two tasks: the paw reach (PR) test and the foot fault (FF) test. Beginning on post-lesion day (D) 2, animals received injections of 2 mg/kg AMP and were injected every third day until D26. Animals were tested both during, and 24 h after, AMP administration. AMP facilitated recovery of skilled forelimb use on the PR test when assessed during drug-free test sessions. No such effect was seen on the FF test. These results demonstrate that sub-acute administration of AMP following a unilateral focal ischaemic lesion of FL can facilitate task-dependent recovery of skilled forelimb use in the rat. They also demonstrate that different behavioural tasks measuring superficially similar behavioural outputs may show different sensitivities to such drug effects.

Topics: Amphetamine; Analysis of Variance; Animals; Brain Injuries; Brain Ischemia; Central Nervous System Stimulants; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Administration Schedule; Endothelin-1; Forelimb; Functional Laterality; Male; Motor Cortex; Motor Skills; Rats; Rats, Inbred Strains; Recovery of Function; Stroke; Stroke Rehabilitation

The purpose of the present set of studies was to develop a new primate model of focal ischemia with reperfusion for long-term functional assessment in the common marmoset. Initially, the cerebral vascular anatomy of the marmoset was interrogated by Araldite-cast and ink-perfusion methods to determine the feasibility of an intravascular surgical approach. The methods showed that the internal carotid artery was highly tortuous in its passage, precluding the development of an extracranial method of inducing temporary middle cerebral artery occlusion in the marmoset. A pilot dose-response study investigated an intracranial approach of topically applying endothelin-1 (ET-1) to the M2 portion of the middle cerebral artery in a small sample of marmosets for up to 6 hours (n = 2 or 3 per group). Dose-dependent reductions in middle cerebral artery vessel caliber followed by gradual reperfusion were inversely related to increases in corrected lesion volume after ET-1 treatment, relative to vehicle control application. Finally, the functional consequences of ET-1-induced lesions to the M2 vascular territory were assessed up to 24 hours after surgery using the optimal dose established in the pilot study (2.5 nmol/25 microL). ET-1-treated marmosets (n = 4) showed marked contralateral motor deficits in grip strength and retrieval of food rewards and contralateral sensory/motor neglect towards tactile stimulation, relative to their ipsilateral side and vehicle-treated marmosets (n = 4). Strong correlations were shown between contralateral impairments and histopathologic parameters, which revealed unilateral putamen and cortical damage to the middle cerebral artery territory. No deficits were shown on general mobility, and self-care was promptly resumed in ET-1 marmosets after surgery. These results show that this novel model of ischemia with reperfusion in the marmoset has the potential to assess long-term function and to gauge the efficacy of novel therapeutic strategies targeted for clinical stroke.

Topics: Animals; Behavior, Animal; Brain; Callithrix; Conditioning, Operant; Disease Models, Animal; Dose-Response Relationship, Drug; Endothelin-1; Epoxy Resins; Female; Forelimb; Hand Strength; Hindlimb; Infarction, Middle Cerebral Artery; Male; Perfusion; Phthalic Anhydrides; Physical Stimulation; Pilot Projects; Reflex; Reperfusion Injury; Reward; Stroke; Vocalization, Animal

Phytoestrogens are considered to be natural selective estrogen receptor modulators exerting antioxidant activity and improving vascular function. However, the mechanisms responsible for their antioxidative effects remain largely unknown. This study tested the hypothesis that genistein may provide significant endothelial protection by antioxidative effects through attenuating NADPH oxidase expression and activity. The results showed that genistein suppressed the expressions of the p22phox NADPH oxidase subunit and angiotensin II (Ang II) type 1 (AT1) receptor in a concentration- and time-dependent manner in aortic endothelial cells from stroke-prone spontaneously hypertensive rats examined by Western blot analysis. Treatment with genistein also remarkably reduced the Ang II-induced superoxide by the reduction of nitroblue tetrazolium, inhibited nitrotyrosine formation, and attenuated endothelin-1 production by ELISA via the stimulation of Ang II. However, when cells were pretreated with ICI-182780, an estrogen-receptor antagonist, at a concentration of 50 micromol/l for 30 min and then co-incubated with ICI-182780 and genistein for 24 h, the inhibitory effect of genistein was not blocked. In contrast, the inhibitory effect of genistein treatment was partially reversed by 30-min pretreatment of endothelial cells with GW9662, a peroxisome proliferator-activated receptor gamma (PPARgamma) antagonist. Genistein thus appears to act as an antioxidant at the transcription level by the downregulation of p22phox and AT1 receptor expression. Our data also showed that the PPARgamma pathway was involved, at least in part, in the inhibitory effect of genistein on the expression of p22phox and AT1 receptors. The endothelial-protective effects of phytoestrogen may contribute to improvement of cardiovascular functions.

Topics: Angiotensin II; Anilides; Animals; Aorta, Thoracic; Cells, Cultured; Endothelin-1; Endothelium, Vascular; Enzyme Inhibitors; Estradiol; Estrogen Antagonists; Fulvestrant; Genistein; Hypertension; Male; Membrane Transport Proteins; NADPH Dehydrogenase; NADPH Oxidases; Phosphoproteins; PPAR gamma; Rats; Rats, Inbred SHR; Receptor, Angiotensin, Type 1; Signal Transduction; Stroke; Superoxides; Tyrosine; Vasoconstrictor Agents

Spontaneously hypertensive stroke-prone rats (SHR-SP) suffer spontaneous stroke in part as a result of abnormal cerebrovascular development. Reduction of regional cerebral blood flow in this model has already been demonstrated. This model has three distinct stages of hypertension: pre-hypertensive, typical hypertensive and malignant hypertensive. We investigated the level of endothelin-1 and its receptor expression in the frontal cortex of SHR-SP at the malignant hypertensive stage (35-40 weeks of age), during which time the rats suffer strokes. The cerebral endothelin-1 level, as determined by enzyme-linked immunosorbent assay, was highly increased at this severely hypertensive stage compared to their genetic control, normotensive Wistar-Kyoto rats. This upregulation was associated with an increased expression of endothelin-A receptor, however, another endothelin-1 receptor, endothelin-B, was downregulated. The regional cerebral blood flow in the frontal cortex was reduced by 60% in 40-week-old malignantly SHR-SP as compared to age-matched Wistar-Kyoto rats. Thus, cerebral endothelin-1 expression increased in malignant hypertension in SHR-SP. The enhanced endothelin-1 may activate the endothelin-A receptor, which would, in turn, result in reduced cerebral blood flow. Downregulation of the endothelin-B receptor may cause suppression of endothelium-derived relaxing factors in the brain of SHR-SP and be an underlying factor in their stroke susceptibility.

Topics: Age Factors; Animals; Blood Flow Velocity; Cerebral Cortex; Cerebrovascular Circulation; Disease Models, Animal; Down-Regulation; Endothelin-1; Hypertension; Male; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Receptor, Endothelin A; Receptor, Endothelin B; Stroke; Up-Regulation

It is already well known that alteration of angiotensin II (Ang II) receptors results in cardiac remodeling in different pathological states, and it is believed that Ang II stimulates the release of endothelin-1 (ET-1). The present study aimed at investigating the interaction between ET-1 and different Ang II receptors in the heart of stroke-prone spontaneously hypertensive rats (SHR-SP). These were treated for 3 months with SB209670, an endothelin-A/endothelin-B dual receptor antagonist, or saline (vehicle) starting from the prehypertensive stage (6 weeks of age). Blood pressure, body weight, heart weight and left ventricular weight were sufficiently decreased after treatment of SHR-SP with SB209670. Ang II type 1 receptor was significantly upregulated in the heart of vehicle-treated SHR-SP compared with the age-matched control, Wistar-Kyoto rat. After endothelin antagonism with SB209670, Ang II type 1 receptor in SHR-SP heart was markedly suppressed. On the other hand, Ang II type 2 receptor was approximately 45% downregulated in the heart of vehicle-treated SHR-SP compared with that of the control, and recovered after endothelin antagonism. The present study demonstrates for the first time the effects of endothelin antagonism on the differential expression and regulation of Ang II receptors in the malignant hypertensive model, SHR-SP, and suggests that the endothelin system may be able to function on the upstream of Ang II signaling.

Topics: Angiotensin II; Animals; Coronary Vessels; Disease Models, Animal; Endothelin A Receptor Antagonists; Endothelin B Receptor Antagonists; Endothelin-1; Hypertension; Indans; Male; Myocardium; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Receptor, Angiotensin, Type 1; Receptor, Angiotensin, Type 2; Receptor, Endothelin A; Receptor, Endothelin B; Signal Transduction; Stroke

To investigate the expression of endothelin (ET)-1 and its receptors in the cerebral arterioles of stroke-prone (spSHR) and control spontaneously hypertensive rats (SHRs) and the changes in endothelin receptor subtypes A and B density elicited by a stroke-permissive diet, before the development of stroke.. Six-week-old SHRs (n=11) and spSHRs (n=11) were assigned to either a regular or a "Japanese"-style diet, in addition to 1% NaCl in the drinking water, for 4 weeks. Cryosections (10 microm thick) of rat brain were assessed for endothelin receptor distribution and density by autoradiography with [125I]ET-1 (10(-10) mol/l) in the presence of cold ET-1 (10(-6) mol/l) or the peptide antagonists BQ-123 (10(-6) mol/l) or BQ-788 (10(-6) mol/l). Reverse transcriptase polymerase chain reaction (RT-PCR) and immunohistochemistry were used to detect specific mRNAs and localize immunoreactive ET-1 and ET(A) and ET(B).. In both strains, immunoreactive ET-1 was detected in the endothelium of cerebral arterioles, and RT-PCR and autoradiography demonstrated the coexistence of both receptor subtypes in brain homogenates and the cerebral arteriole walls, respectively. With the regular diet, the ET(A) receptor density was lower in SHRs than in spSHRs (P = 0.007), whereas the ET(B) receptor density was similar (P = NS). The Japanese-style diet increased the density of ET(A) receptors (P = 0.006) in SHRs, but decreased it (P = 0.019) in spSHRs. No effect was seen on ET(B) receptor density.. ET(A) and ET(B) receptor subtypes are expressed in the wall of cerebral arterioles of SHRs and spSHRs. The latter strain showed a marked increase in ET(A) receptor density under a regular diet, in addition to an altered regulation in response to a stroke-permissive diet.

Topics: Animals; Arterioles; Brain; Cerebrovascular Circulation; Diet; Endothelin-1; Endothelins; Gene Expression; Genetic Predisposition to Disease; Hypertension; Immunohistochemistry; Japan; Protein Isoforms; Protein Precursors; Rats; Rats, Inbred SHR; Receptor, Endothelin A; Receptors, Endothelin; Stroke

Hyperthermia during or after stroke is known to worsen neuronal damage. Paradoxically, when hyperthermia precedes stroke, it can protect against a subsequent ischemic insult. Other stressors including restraint also have a similar pre-conditioning effect. In the present study, we report the unanticipated finding that conscious rats, restrained for the purpose of intravenous infusion, had markedly reduced neuronal and functional deficits after middle cerebral artery occlusion compared with unrestrained rats. Restrained rats had significantly higher body temperature prior to stroke than unrestrained rats. The findings suggest restraint leading to mild hyperthermia may be sufficient to induce adaptive processes which protect against subsequent ischemia.

Topics: Adaptation, Physiological; Animals; Body Temperature; Brain Ischemia; Cerebral Cortex; Cerebral Infarction; Corpus Striatum; Endothelin-1; Hyperthermia, Induced; Male; Motor Activity; Rats; Rats, Wistar; Restraint, Physical; Stroke

Endothelins (ETs) are potent vasoconstrictors and may play a role in the pathophysiology of several diseases. Limited and controversial data exist on their role in human ischemic stroke. We planned a prospective, observational, and longitudinal clinical study to test whether ET-1 levels increase in various phases of ischemic stroke and whether the ET-1 levels correlate with neurological scores, stroke etiology, stroke risk factors, or final outcome.. We measured plasma ET-1 levels with a sandwich-enzyme immunoassay method in 101 consecutive patients with ischemic stroke on admission and 1 week, 1 month, and 3 months after stroke and in 101 sex- and age-matched control subjects. At each sampling, the patients underwent a complete neurological evaluation. All stroke risk factors were recorded, an array of laboratory tests were performed, and the subtype of ischemic stroke was determined. The patients were contacted 3 years later for prognostic determination.. ET-1 levels in patients (2.4+/-1.3 pg/mL on admission, 2.2+/-1.4 pg/mL at 1 week, 2.1+/-1.4 pg/mL at 1 month, and 2.1+/-1.2 pg/mL at 3 months) were not different from those of the control subjects (2.2+/-0.9 pg/mL) at any time point. No correlation was found between the ET-1 levels and stroke etiology, stroke risk factors, stroke recurrence risk, age, sex, or neurological scores, except that ET-1 levels correlated with the use of warfarin and with body mass index.. Plasma ET-1 levels were normal in patients with ischemic stroke. Our findings cannot exclude a role of ETs in the pathophysiology of ischemic stroke because plasma levels might not accurately reflect intracerebral concentrations, but they also do not support the occurrence of a major plasma ET-1 level increase at any phase of stroke. Our patient population is the largest ever reported in whom ET-1 levels were measured, but it consisted of mild and moderately ill patients with stroke due to the study design, of which the aim was long-term observation, which excludes severely ill patients.

Topics: Adult; Aged; Aged, 80 and over; Anticoagulants; Body Mass Index; Brain Ischemia; Endothelin-1; Female; Humans; Male; Middle Aged; Nervous System; Prognosis; Reference Values; Risk Factors; Stroke; Warfarin

We have demonstrated previously that endothelin-1 (ET-1) mRNA expression is increased in hypertensive rats. The aim of the study reported here was to elucidate the effects of the endothelin (ET) receptor antagonist on the hemodynamic and biochemical parameters in stroke-prone spontaneously hypertensive rats (SHRSPs/Izm). The endothelin-A- and -B- (ETA/ETB) receptor antagonist (TAK-044, Takeda Chemical Industries, Osaka, Japan) was administered subcutaneously at a dose of 10 mg/kg/day from the age of 8 weeks for 4 weeks. Blood samples and tissues of the kidney, heart and brain were obtained at the age of 12 weeks. Tissue expression of ET-1 mRNA was determined by reverse transcriptase-polymerase chain reaction (RT-PCR) followed by Southern blot analysis. Treatment with TAK-044 resulted in a significant decrease in systolic blood pressure (SBP), blood urea nitrogen (BUN), serum creatinine concentration, plasma aldosterone level, heart weight, and kidney weight. In addition, ET-1 contents and mRNA expression level in the kidney, heart and brain were significantly decreased by the treatment with TAK-044. These results suggest that the ET receptor antagonist TAK-044 is able to attenuate ET-1 gene expression in addition to its specific antagonism of the biological actions of ET via the receptors.

Topics: Animals; Endothelin Receptor Antagonists; Endothelin-1; Hemodynamics; Hypertension; Male; Peptides, Cyclic; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Receptor, Endothelin A; Receptor, Endothelin B; RNA, Messenger; Stroke

Increased levels of endothelin (ET) have been demonstrated in the ischemic brain, and ET receptor antagonism has been shown to improve outcome in cerebral ischemia. However, no previous work has been carried out evaluating the role of ET and its antagonism in brain trauma as compared to experimental stroke. In this study, we evaluated changes in brain ET levels following closed head injury (CHI) and the effects of SB 234551, an endothelin-A- (ET(A)) selective antagonist, and SB 209670, a mixed endothelin-A- and -B- (ET(A)/ET(B)) antagonist, on outcome in CHI and focal stroke. Male Sabra rats were subjected to CHI (weight drop model). Male Sprague Dawley rats were subjected to focal stroke (intraluminal suture model). Motor function(s) were assessed and immunoreactive ET (irET) and the degree of cerebral edema were measured for 24 h after CHI. Brain swelling (edema), neurological deficits and forebrain infarct volumes were measured 24 h after focal stroke. Antagonists (total doses of 7.5, 15, 30 or 60 mg/kg) were administered intravenously for 6-24 h (beginning 15 min after injury). Control rats were infused with vehicle. CHI resulted in increased ET levels in the directly contused hemisphere at 12 and 24 h. In addition, SB 234551 significantly reduced neurological deficits (decreased 30%) and brain edema (decreased 40%) following CHI (p < 0.05 at 60 mg/kg dose). SB 209670 had no effects on CHI outcome. Focal stroke studies yielded similar results. SB 234551 reduced focal stroke-induced neurological deficits by 50%, brain swelling by 54% and the degree of infarction by 36% (p < 0.05 at 30 mg/kg). SB 209670 did not provide any neuroprotection in focal stroke. These data indicate that ET plays a significant role in the pathophysiology of CHI, and that selectively targeting ET(A)-receptors similarly in both CHI and stroke might be a therapeutic opportunity.

Topics: Animals; Craniocerebral Trauma; Dioxoles; Endothelin Receptor Antagonists; Endothelin-1; Indans; Male; Neuroprotective Agents; Pyrazoles; Rats; Rats, Sprague-Dawley; Receptor, Endothelin A; Stroke