abs-201 and Disease-Models--Animal

Neurotensin is an endogenous tridecapeptide that binds to neurotensin receptors in the brain, which induce hypothermia. The aim of this study was to investigate whether the receptor agonist ABS 201 could induce therapeutic hypothermia and improve postresuscitation outcomes in a ventricular fibrillation cardiac arrest (VFCA) rat model. VF was electrically induced in 12 rats. Defibrillation was achieved after 6 min of cardiopulmonary resuscitation. After successful resuscitation, animals were randomized to receive ABS 201 (8 mg/kg/h) or placebo. Postresuscitation myocardial function and neurological deficit scores (NDS) were assessed, and postresuscitation survival duration was observed for up to 72 h. After administration of ABS 201, blood temperature decreased significantly from 37°C to 34°C, and was maintained for 2.5 h. There was a significant improvement of postresuscitation myocardial dysfunction, NDS, and survival duration in animals treated with ABS 201. These results demonstrated that ABS 201 induces therapeutic hypothermia in a VFCA rat model, ameliorates postresuscitation myocardial-neurological dysfunction, and prolongs survival duration. ABS 201 may therefore be an alternative method to induce therapeutic hypothermia with current cooling methods and improve postresuscitation outcomes.

Topics: Animals; Body Temperature; Cardiopulmonary Resuscitation; Disease Models, Animal; Heart Arrest; Hypothermia, Induced; Male; Oligopeptides; Rats; Rats, Sprague-Dawley; Receptors, Neurotensin; Resuscitation; Treatment Outcome; Ventricular Fibrillation

Focal cerebral ischemia results in an ischemic core surrounded by the peri-infarct region (penumbra). Most research attention has been focused on penumbra while the pattern of cell fates inside the ischemic core is poorly defined. In the present investigation, we tested the hypothesis that, inside the ischemic core, some neuronal and vascular cells could survive the initial ischemic insult while regenerative niches might exist many days after stroke in the adult brain. Adult mice were subjected to focal cerebral ischemia induced by permanent occlusion of distal branches of the middle cerebral artery (MCA) plus transient ligations of bilateral common carotid artery (CCA). The ischemic insult uniformly reduced the local cerebral blood flow (LCBF) by 90%. Massive cell death occurred due to multiple mechanisms and a significant infarction was cultivated in the ischemic cortex 24 h later. Nevertheless, normal or even higher levels of brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) persistently remained in the core tissue, some NeuN-positive and Glut-1/College IV-positive cells with intact ultrastructural features resided in the core 7-14 days post stroke. BrdU-positive but TUNEL-negative neuronal and endothelial cells were detected in the core where extensive extracellular matrix infrastructure developed. Meanwhile, GFAP-positive astrocytes accumulated in the penumbra and Iba-1-positive microglial/macrophages invaded the core several days after stroke. The long term survival of neuronal and vascular cells inside the ischemic core was also seen after a severe ischemic stroke induced by permanent embolic occlusion of the MCA. We demonstrate that a therapeutic intervention of pharmacological hypothermia could save neurons/endothelial cells inside the core. These data suggest that the ischemic core is an actively regulated brain region with residual and newly formed viable neuronal and vascular cells acutely and chronically after at least some types of ischemic strokes.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Brain Infarction; Carotid Stenosis; Cells, Cultured; Cerebrovascular Circulation; Disease Models, Animal; Endothelial Cells; Gene Expression Regulation; Glucose Transporter Type 1; Infarction, Middle Cerebral Artery; Membrane Proteins; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microglia; Neurons; Neuroprotective Agents; Oligopeptides; Phosphopyruvate Hydratase; Protein Binding; Regeneration; Tubulin

Stroke is a leading threat to human life and health in the US and around the globe, while very few effective treatments are available for stroke patients. Preclinical and clinical studies have shown that therapeutic hypothermia (TH) is a potential treatment for stroke. Using novel neurotensin receptor 1 (NTR1) agonists, we have demonstrated pharmacologically induced hypothermia and protective effects against brain damages after ischemic stroke, hemorrhage stroke, and traumatic brain injury (TBI) in rodent models. To further characterize the mechanism of TH-induced brain protection, we examined the effect of TH (at ±33°C for 6h) induced by the NTR1 agonist HPI-201 or physical (ice/cold air) cooling on inflammatory responses after ischemic stroke in mice and oxygen glucose deprivation (OGD) in cortical neuronal cultures. Seven days after focal cortical ischemia, microglia activation in the penumbra reached a peak level, which was significantly attenuated by TH treatments commenced 30min after stroke. The TH treatment decreased the expression of M1 type reactive factors including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-12, IL-23, and inducible nitric oxide synthase (iNOS) measured by RT-PCR and Western blot analyses. Meanwhile, TH treatments increased the expression of M2 type reactive factors including IL-10, Fizz1, Ym1, and arginase-1. In the ischemic brain and in cortical neuronal/BV2 microglia cultures subjected to OGD, TH attenuated the expression of monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1α (MIP-1α), two key chemokines in the regulation of microglia activation and infiltration. Consistently, physical cooling during OGD significantly decreased microglia migration 16h after OGD. Finally, TH improved functional recovery at 1, 3, and 7days after stroke. This study reveals the first evidence for hypothermia mediated regulation on inflammatory factor expression, microglia polarization, migration and indicates that the anti-inflammatory effect is an important mechanism underlying the brain protective effects of a TH therapy.

Topics: Animals; Calcium-Binding Proteins; Cell Movement; Cell Polarity; Cells, Cultured; Cerebral Cortex; Cytokines; Disease Models, Animal; Embryo, Mammalian; Glucose; Hypothermia, Induced; Hypoxia; Infarction, Middle Cerebral Artery; Male; Mice; Mice, Inbred C57BL; Microfilament Proteins; Microglia; Neurons; Oligopeptides; Oxygen; Phosphopyruvate Hydratase; Recovery of Function

Neonatal brain trauma is linked to higher risks of mortality and neurological disability. The use of mild to moderate hypothermia has shown promising potential against brain injuries induced by stroke and traumatic brain injury (TBI) in various experimental models and in clinical trials. Conventional methods of physical cooling, however, are difficult to use in acute treatments and in induction of regulated hypothermia. In addition, general anesthesia is usually required to mitigate the negative effects of shivering during physical cooling. Our recent investigations demonstrate the potential therapeutic benefits of pharmacologically induced hypothermia (PIH) using the neurotensin receptor (NTR) agonist HPI201 (formerly known as ABS201) in stroke and TBI models of adult rodents. The present investigation explored the brain protective effects of HPI201 in a P14 rat pediatric model of TBI induced by controlled cortical impact. When administered via intraperitoneal (i.p.) injection, HPI201 induced dose-dependent reduction of body and brain temperature. A 6-h hypothermic treatment, providing an overall 2-3°C reduction of brain and body temperature, showed significant effect of attenuating the contusion volume versus TBI controls. Attenuation occurs whether hypothermia is initiated 15min or 2h after TBI. No shivering response was seen in HPI201-treated animals. HPI201 treatment also reduced TUNEL-positive and TUNEL/NeuN-colabeled cells in the contusion area and peri-injury regions. TBI-induced blood-brain barrier damage was attenuated by HPI201 treatment, evaluated using the Evans Blue assay. HPI201 significantly decreased MMP-9 levels and caspase-3 activation, both of which are pro-apototic, while it increased anti-apoptotic Bcl-2 gene expression in the peri-contusion region. In addition, HPI201 prevented the up-regulation of pro-inflammatory tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and IL-6. In sensorimotor activity assessments, rats in the HPI201 treated group exhibited improved functional recovery after TBI versus controls. These data support that PIH therapy using our NTR agonist is effective in reducing neuronal and BBB damage, attenuating inflammatory response and detrimental cellular signaling, and promoting functional recovery after TBI in the developing brain, supporting its potential for further evaluation towards clinical development.

Topics: Animals; Animals, Newborn; Blood-Testis Barrier; Body Temperature; Brain Injuries; Caspase 3; Disease Models, Animal; Dose-Response Relationship, Drug; Hypothermia, Induced; In Situ Nick-End Labeling; Interleukin-1beta; Matrix Metalloproteinase 9; Oligopeptides; Phosphopyruvate Hydratase; Proto-Oncogene Proteins c-bcl-2; Rats; Rats, Wistar; Recovery of Function; Time Factors; Tumor Necrosis Factor-alpha

Compelling evidence from preclinical and clinical studies has shown that mild to moderate hypothermia is neuroprotective against ischemic stroke. Clinical applications of hypothermia therapy, however, have been hindered by current methods of physical cooling, which is generally inefficient and impractical in clinical situations. In this report, we demonstrate the potential of pharmacologically induced hypothermia (PIH) by the novel neurotensin receptor 1 (NTR1) agonist ABS-201 in a focal ischemic model of adult mice. ABS-201 (1.5-2.5 mg/kg, i.p.) reduces body and brain temperature by 2-5°C in 15-30 min in a dose-dependent manner without causing shivering or altering physiological parameters. Infarct volumes at 24 h after stroke are reduced by ∼30-40% when PIH therapy is initiated either immediately after stroke induction or after 30-60 min delay. ABS-201 treatment increases bcl-2 expression, decreases caspase-3 activation, and TUNEL-positive cells in the peri-infarct region, and suppresses autophagic cell death compared to stroke controls. The PIH therapy using ABS-201 improves recovery of sensorimotor function as tested 21 d after stroke. These results suggest that PIH induced by neurotensin analogs represented by ABS-201 are promising candidates for treatment of ischemic stroke and possibly for other ischemic or traumatic injuries.

Topics: Animals; Apoptosis; Autophagy; Body Temperature; Brain Ischemia; Cerebral Infarction; Cerebrovascular Circulation; Disease Models, Animal; Hypothermia, Induced; Male; Mice; Mice, Inbred C57BL; Motor Skills; Neuroprotective Agents; Neurotensin; Oligopeptides; Receptors, Neurotensin