Many therapies have shown promise in preclinical stroke studies, but few benefit patients. A greater understanding of stroke pathophysiology is needed to successfully develop therapies, and this depends on appropriate animal models. The collagenase and blood infusion models of intracerebral hemorrhage (ICH) are widely used; yet, investigators often prefer using one model for a variety of reasons. Thus, we directly compared these to highlight advantages and limitations of each as well as the assessment approach. An ICH was created by infusing blood or bacterial collagenase into the rats' striatum. We matched initial hematoma volume in each model (Experiment 1) and assessed the time course of bleeding (Experiment 2). Functional deficits and the progression of injury were tracked over 6 weeks using behavior, magnetic resonance imaging, and histology (Experiment 3). Despite similar initial hematoma volumes, collagenase-induced ICH resulted in a greater bloodbrain barrier breakdown and more damage to the striatum, substantia nigra, white matter, and cortex. Magnetic resonance imaging revealed faster hematoma resolution in the blood model, and little increase in the volume of tissue lost from 1 to 6 weeks. In contrast, tissue loss continued over 4 weeks in the collagenase model. Finally, functional deficits recovered more quickly and completely in the blood model. This study highlights key differences between these models and that neither closely replicates the human condition. Thus, both should be used whenever possible taking into account the significant differences between these models and their limitations. Furthermore, this work illustrates significant weaknesses with several outcome measures.

The blood–brain barrier formed by the brain capillary endothelial cells provides a protective barrier between the systemic blood and the extracellular environment of the CNS. As most fatty acids in the brain enter from the blood, we examined the mechanism of oleate (C18:1) transport across primary human brain microvessel endothelial cells (HBMEC). The permeability of [1‐14C]oleate was determined using confluent cells grown on Transwell® inserts in both the absence or presence of bovine serum albumin in the basolateral media, and following inhibition of various fatty acid transporters. The passage of [1‐14C]oleate across confluent HBMEC monolayers was significantly enhanced when fatty acid free albumin was present in the basolateral media. The presence of the non‐specific fatty acid uptake inhibitor phloretin significantly decreased [1‐14C]oleate uptake by HBMEC and the subsequent release of [1‐14C]oleate into the basolateral medium. Knockdown of fatty acid transport protein‐1 or fatty acid translocase/CD36 significantly decreased [1‐14C]oleate transport across the HBMEC monolayer from either apical as well as basolateral sides. The findings indicate that a fatty acid acceptor is a requirement for oleate transport across HBMEC monolayers. In addition, transport of oleate across HBMEC is, in part, a transcellular process mediated by fatty acid transport proteins.

Introduction: Sphingosine 1‐phosphate (S1P), an endogenous phospholipid, is involved in pre‐conditioning responses in the heart. The present study evaluated whether exogenous S1P could have a similar protective role in the cerebral microvasculature following hypoxic insult.Methods: Human brain microvessel endothelial cells (HBMECs) were exposed to oxygen‐glucose deprivation (OGD) for 0–6 hours. Cell viability was assessed using MTT assay immediately after OGD or following a 24‐hr re‐oxygenation period. The effects of S1P on OGD‐mediated cell toxicity was determined by pre‐treating the cells with various concentrations of S1P (0–10 μM) for 0, 1, or 24 hours.Results: Exposure of HBMECs to OGD resulted in a significant decrease (approximately 20%) in cell viability when assessed immediately after OGD. Pre‐treating HBMEC cells with S1P for 1 hr prior to OGD provided a dose dependent protection, with 1.0 and 10 μM S1P completely reversing the loss in cell viability associated with OGD at all time points examined. However, the protective effects of S1P were not apparent in the 24‐hour pre‐treatment protocol.Conclusion: Activation of S1P receptors within the brain microvasculature prior to hypoxic events may help prevent toxicity to the cerebral microvasculature.Funding support provided by Canadian Institutes of Health Research and Manitoba Health Research Council.