Large-Scale Multivariate Analysis to Interrogate an Animal Model of Stroke: Novel Insights Into Poststroke Pathology.

Background And Purpose: Preclinical stroke studies endeavor to model the pathophysiology of clinical stroke, assessing a range of parameters of injury and impairment. However, poststroke pathology is complex and variable, and associations between diverse parameters may be difficult to identify within the usual small study designs that focus on infarct size.

Methods: We have performed a retrospective large-scale big data analysis of records from 631 C57BL/6 mice of either sex in which the middle cerebral artery was occluded by 1 of 5 surgeons either transiently for 1 hour followed by 23-hour reperfusion (transient middle cerebral artery occlusion [MCAO]; n=435) or permanently for 24 hours without reperfusion (permanent MCAO; n=196).

microRNA-367-3p regulation of GPRC5A is suppressed in ischemic stroke.

Ischemic stroke is a major cause of mortality and long-term disability with limited treatment options, and a greater understanding of the gene regulatory mechanisms underlying ischemic stroke-associated neuroinflammation is required for new therapies. To study ischemic stroke , mice were subjected to sustained ischemia by intraluminal filament-induced middle cerebral artery occlusion (MCAo) for 24 h without reperfusion or transient ischemia for 30 min followed by 23.5 h reperfusion, and brain miRNA and mRNA expression changes were quantified by TaqMan OpenArrays and gene (mRNA) expression arrays, respectively.

Local Injection of Endothelin-1 in the Early Neonatal Rat Brain Models Ischemic Damage Associated with Motor Impairment and Diffuse Loss in Brain Volume.

Cerebral palsy is an irreversible movement disorder resulting from cerebral damage sustained during prenatal or neonatal brain development. As survival outcomes for preterm injury improve, there is increasing need to model ischemic injury at earlier neonatal time-points to better understand the subsequent pathological consequences. Here we demonstrate a novel neonatal ischemic model using focal administration of the potent vasoconstrictor peptide, endothelin-1 (ET-1), in newborn rats.

IL-33 modulates inflammatory brain injury but exacerbates systemic immunosuppression following ischemic stroke.

Stroke triggers a complex inflammatory process in which the balance between pro- and antiinflammatory mediators is critical for the development of the brain infarct. However, systemic changes may also occur in parallel with brain inflammation. Here we demonstrate that administration of recombinant IL-33, a recently described member of the IL-1 superfamily of cytokines, promotes Th2-type effects following focal ischemic stroke, resulting in increased plasma levels of Th2-type cytokines and fewer proinflammatory (3-nitrotyrosine+F4/80+) microglia/macrophages in the brain.

Acute or Delayed Systemic Administration of Human Amnion Epithelial Cells Improves Outcomes in Experimental Stroke.

Background And Purpose: Human amnion epithelial cells (hAECs) are nonimmunogenic, nontumorigenic, anti-inflammatory cells normally discarded with placental tissue. We reasoned that their profile of biological features, wide availability, and the lack of ethical barriers to their use could make these cells useful as a therapy in ischemic stroke.

Methods: We tested the efficacy of acute (1.

Evidence of CCR2-independent transmigration of Ly6C(hi) monocytes into the brain after permanent cerebral ischemia in mice.

Previously we showed that INCB3344, a CCR2 antagonist, inhibits transmigration of Ly6C(hi) monocytes into the brain after ischemia-reperfusion. Here we tested the effect of CCR2 inhibition during permanent cerebral ischemia. Mice were administered either vehicle (dimethyl sulfoxide/carboxymethylcellulose) or INCB3344 (30 or 100mg/kg IP) 1h before middle cerebral artery occlusion and at 2 and 6h after the initiation of ischemia.

Effect of a Selective Mas Receptor Agonist in Cerebral Ischemia In Vitro and In Vivo.

Functional modulation of the non-AT1R arm of the renin-angiotensin system, such as via AT2R activation, is known to improve stroke outcome. However, the relevance of the Mas receptor, which along with the AT2R forms the protective arm of the renin-angiotensin system, as a target in stroke is unclear. Here we tested the efficacy of a selective MasR agonist, AVE0991, in in vitro and in vivo models of ischemic stroke.

Changes in Hypoxia-Inducible Factor-1 (HIF-1) and Regulatory Prolyl Hydroxylase (PHD) Enzymes Following Hypoxic-Ischemic Injury in the Neonatal Rat.

Hypoxia leads to activation of many cellular adaptive processes which are regulated by the transcription factor hypoxia-inducible factor-1 (HIF-1). HIF-1 consists of HIF-1α and HIF-1ß subunits and levels of HIF-1α protein are regulated by HIF prolyl-hydroxylase enzymes (PHD1, 2, 3). The aim of the current study was to investigate the expression of HIF-1α and PHDs at various time points after hypoxia-ischemia (HI), using a neonatal rat model of HI brain injury.

Evidence That Ly6C(hi) Monocytes are Protective in Acute Ischemic Stroke by Promoting M2 Macrophage Polarization.

Background And Purpose: Ly6C(hi) monocytes are generally thought to exert a proinflammatory role in acute tissue injury, although their impact after injuries to the central nervous system is poorly defined. CC chemokine receptor 2 is expressed on Ly6C(hi) monocytes and plays an essential role in their extravasation and transmigration into the brain after cerebral ischemia. We used a selective CC chemokine receptor 2 antagonist, INCB3344, to assess the effect of Ly6C(hi) monocytes recruited into the brain early after ischemic stroke.

Effect of a broad-specificity chemokine-binding protein on brain leukocyte infiltration and infarct development.

Background And Purpose: Expression of numerous chemokine-related genes is increased in the brain after ischemic stroke. Here, we tested whether post-stroke administration of a chemokine-binding protein (CBP), derived from the parapoxvirus bovine papular stomatitis virus, might reduce infiltration of leukocytes into the brain and consequently limit infarct development.

Methods: The binding spectrum of the CBP was evaluated in chemokine ELISAs, and binding affinity was determined using surface plasmon resonance.

Brain immune cell composition and functional outcome after cerebral ischemia: comparison of two mouse strains.

Inflammatory cells may contribute to secondary brain injury following cerebral ischemia. The C57Bl/6 mouse strain is known to exhibit a T helper 1-prone, pro-inflammatory type response to injury, whereas the FVB strain is relatively T helper 2-prone, or anti-inflammatory, in its immune response. We tested whether stroke outcome is more severe in C57Bl/6 than FVB mice.

Role of CCR2 in inflammatory conditions of the central nervous system.

CC chemokine receptor 2 (CCR2) plays important roles in extravasation and transmigration of monocytes under inflammatory conditions. CCR2 and its ligands have been extensively studied in a range of inflammatory diseases in the central nervous system (CNS), including multiple sclerosis, Alzheimer's disease and ischemic stroke. This brief review summarizes our current understanding of the physiologic and pathologic roles of CCR2, focusing on its involvement in CNS inflammatory diseases.

Sex-dependent effects of G protein-coupled estrogen receptor activity on outcome after ischemic stroke.

Background And Purpose: Experimental studies indicate that estrogen typically, but not universally, has a neuroprotective effect in stroke. Ischemic stroke increases membrane-bound G protein-coupled estrogen receptor (GPER) distribution and expression in the brain of male but not female mice. We hypothesized that GPER activation may have a greater neuroprotective effect in males than in females after stroke.

Immune cell infiltration in malignant middle cerebral artery infarction: comparison with transient cerebral ischemia.

We tested whether significant leukocyte infiltration occurs in a mouse model of permanent cerebral ischemia. C57BL6/J male mice underwent either permanent (3 or 24 hours) or transient (1 or 2 hours+22- to 23-hour reperfusion) middle cerebral artery occlusion (MCAO). Using flow cytometry, we observed ∼15,000 leukocytes (CD45(+high) cells) in the ischemic hemisphere as early as 3 hours after permanent MCAO (pMCAO), comprising ∼40% lymphoid cells and ∼60% myeloid cells.