anandamide and Stroke

Stroke is a major cause of morbidity and mortality and follows heart disease and cancer as the third leading cause of death in Western societies [1]. Despite many advances in stroke research and pharmacotherapy, clinical treatment of this debilitating disorder is still inadequate. Recent findings from several laboratories have identified the endocannabinoid signaling pathway, comprised of the endocannabinoid agonist anandamide and its pharmacological targets, CB1 and CB2 cannabinoid receptors and associated anandamide receptors, as a physiological system with capacity to mitigate cardiovascular and cerebrovascular disorders through neuronal and endothelial actions. Variability in experimental stroke models and modes of outcome evaluation, however, have provoked controversy regarding the precise roles of endocannabinoid signals in mediating neural and/or vascular protection versus neurovascular damage. Clinical trials of the CB1 antagonist rimonabant demonstrate that modulation of endocannabinoid signaling during metabolic regulation of vascular disorders can significantly impact clinical outcomes, thus providing strong argument for therapeutic utility of endocannabinoids and/or cannabinoid receptors as targets for therapeutic intervention in cases of stroke and associated vascular disorders. The purpose of this review is to provide updated information from basic science and clinical perspectives on endocannabinoid ligands and their effects in the pathophysiologic genesis of stroke. Particular emphasis will be placed on the endocannabinoids anandamide and 2-arachidonylglycerol and CB1 receptor-mediated mechanisms in the neurovascular unit during stroke pathogenesis. Deficiencies in our knowledge of endocannabinoids in the etiology and pathogenesis of stroke, caveats and limitations of existing studies, and future directions for investigation will be addressed.

Topics: Arachidonic Acids; Brain Ischemia; Cannabinoid Receptor Modulators; Endocannabinoids; Glycerides; Humans; Matrix Metalloproteinases; Polyunsaturated Alkamides; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Signal Transduction; Stroke

The functional significance of adult neural stem and progenitor cells in hippocampal-dependent learning and memory has been well documented. Although adult neural stem and progenitor cells in the subventricular zone are known to migrate to, maintain and reorganize the olfactory bulb, it is less clear whether they are functionally required for other processes. Using a conditional transgenic mouse model, selective ablation of adult neural stem and progenitor cells in the subventricular zone induced a dramatic increase in morbidity and mortality of central nervous system disorders characterized by excitotoxicity-induced cell death accompanied by reactive inflammation, such as 4-aminopyridine-induced epilepsy and ischaemic stroke. To test the role of subventricular zone adult neural stem and progenitor cells in protecting central nervous system tissue from glutamatergic excitotoxicity, neurophysiological recordings of spontaneous excitatory postsynaptic currents from single medium spiny striatal neurons were measured on acute brain slices. Indeed, lipopolysaccharide-stimulated, but not unstimulated, subventricular zone adult neural stem and progenitor cells reverted the increased frequency and duration of spontaneous excitatory postsynaptic currents by secreting the endocannabinod arachidonoyl ethanolamide, a molecule that regulates glutamatergic tone through type 1 cannabinoid receptor (CB(1)) binding. In vivo restoration of cannabinoid levels, either by administration of the type 1 cannabinoid receptor agonist HU210 or the inhibitor of the principal catabolic enzyme fatty acid amide hydrolase, URB597, completely reverted the increased morbidity and mortality of adult neural stem and progenitor cell-ablated mice suffering from epilepsy and ischaemic stroke. Our results provide the first evidence that adult neural stem and progenitor cells located within the subventricular zone exert an 'innate' homeostatic regulatory role by protecting striatal neurons from glutamate-mediated excitotoxicity.

Topics: 4-Aminopyridine; Amidohydrolases; Animals; Arachidonic Acids; Benzamides; Carbamates; Corpus Striatum; Disease Models, Animal; Dronabinol; Endocannabinoids; Epilepsy; Excitatory Amino Acid Antagonists; Excitatory Postsynaptic Potentials; Ganciclovir; Glutamic Acid; Lateral Ventricles; Lipopolysaccharides; Mice; Mice, Inbred C57BL; Mice, Transgenic; Neural Stem Cells; Neuroprotective Agents; Polyunsaturated Alkamides; Stem Cells; Stroke

Endocannabinoids (eCBs) are ubiquitous lipid mediators that act on specific (CB1, CB2) and non-specific (TRPV1, PPAR) receptors. Despite many experimental animal studies proved eCB involvement in the pathogenesis of stroke, such evidence is still lacking in human patients. Our aim was to determine eCB peripheral levels in acute stroke patients and evaluate their relationship with clinical disability and stroke volume.. A cohort of ten patients with a first acute (within six hours since symptoms onset) ischemic stroke and a group of eight age- and sex-matched normal subjects were included. Groups were also matched for metabolic profile. All subjects underwent a blood sample collection for anandamide (AEA), 2-arachidonoylglycerol (2-AG) and palmitoylethanolamide (PEA) measurement; blood sampling was repeated in patients on admission (T0), at 6 (T1) and 18 hours (T2) thereafter. Patients neurological impairment was assessed using NIHSS and Fugl-Meyer Scale arm subitem (FMSa); stroke volume was determined on 48 h follow-up brain CT scans. Blood samples were analyzed by liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry.. 1)T0 AEA levels were significantly higher in stroke patients compared to controls. 2)A significant inverse correlation between T0 AEA levels and FMSa score was found. Moreover a positive correlation between T0 AEA levels and stroke volume were found in stroke patients. T0 PEA levels in stroke patients were not significantly different from the control group, but showed a significant correlation with the NIHSS scores. T0 2-AG levels were lower in stroke patients compared to controls, but such difference did not reach the significance threshold.. This is the first demonstration of elevated peripheral AEA levels in acute stroke patients. In agreement with previous murine studies, we found a significant relationship between AEA or PEA levels and neurological involvement, such that the greater the neurological impairment, the higher were these levels.

Topics: Aged; Aged, 80 and over; Amides; Arachidonic Acids; Cannabinoid Receptor Modulators; Chromatography, Liquid; Endocannabinoids; Ethanolamines; Glycerides; Humans; Male; Mass Spectrometry; Metabolomics; Middle Aged; Nervous System Diseases; Palmitic Acids; Polyunsaturated Alkamides; Stroke

Oxygen depletion (O(2)) and a decrease in pH are initial pathophysiological events in stroke development, but secondary mechanisms of ischemic cell death are incompletely understood. By patch-clamp recordings of brain slice preparations we show that TASK1 and TASK3 channels are inhibited by pH-reduction (42+/-2%) and O(2) deprivation (36+/-5%) leading to membrane depolarization, increased input resistance and a switch in action potential generation under ischemic conditions. In vivo TASK blockade by anandamide significantly increased infarct volumes at 24 h in mice undergoing 30 min of transient middle cerebral artery occlusion (tMCAO). Moreover, blockade of TASK channels accelerated stroke development. Supporting these findings TASK1(-/-) mice developed significantly larger infarct volumes after tMCAO accompanied by worse outcome in functional neurological tests compared to wild type mice. In conclusion, our data provide evidence for an important role of functional TASK channels in limiting tissue damage during cerebral ischemia.

Topics: Acidosis; Animals; Arachidonic Acids; Brain; Brain Ischemia; Endocannabinoids; Hypoxia, Brain; In Vitro Techniques; Infarction, Middle Cerebral Artery; Male; Membrane Potentials; Mice; Mice, Inbred C57BL; Mice, Knockout; Nerve Tissue Proteins; Neurons; Polyunsaturated Alkamides; Potassium Channels; Potassium Channels, Tandem Pore Domain; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; RNA, Messenger; Stroke; Thalamus; TRPV Cation Channels

We investigated levels and compositions of N-acylethanolamines (NAEs) and their precursors, N-acyl phosphatidylethanolamines (N-acyl PEs), in a rat stroke model applying striatal microdialysis for glutamate assay. Rats (n = 18) were treated with either intravenous saline (control), NMDA receptor antagonist MK801 (1 mg/kg), or CB1 receptor antagonist SR141716A (1 mg/kg) 30 min after permanent middle cerebral artery occlusion (MCAO). MK801 significantly attenuated the release of glutamate in the infarcted striatum (79 +/- 22 micromol/L) as compared with controls (322 +/- 104 micromol/L). The administration of CB1 antagonist SR141716A had no statistically significant effect on glutamate release (340 +/- 89 micromol/L), but reduced infarct volume at 5 h after MCAO significantly by approximately 40%, whereas MK801 treatment resulted in a non-significant (18%) reduction of infarct volume. In controls, striatal and cortical NAE concentrations were about 30-fold higher in the infarcted than in the non-infarcted hemisphere, whereas ipsilateral N-acyl phosphatidylethanolamine (N-acyl PE) levels exceeded contralateral levels by only a factor of two to three. Treatment with MK801 or SR141716A, or glutamate release in the infarcted tissue, had no significant effect on these levels. NAE accumulation during acute stroke may be due to increased synthesis as well as decreased degradation, possibly by inhibition of fatty acid amide hydrolase (FAAH).

Topics: Acute Disease; Animals; Arachidonic Acids; Brain Ischemia; Cerebral Cortex; Corpus Striatum; Disease Models, Animal; Dizocilpine Maleate; Endocannabinoids; Ethanolamines; Excitatory Amino Acid Antagonists; Extracellular Fluid; Male; Microdialysis; Phospholipids; Piperidines; Polyunsaturated Alkamides; Pyrazoles; Rats; Rats, Wistar; Receptor, Cannabinoid, CB1; Receptors, N-Methyl-D-Aspartate; Rimonabant; Signal Transduction; Stroke

Excitotoxic insults such as stroke may induce release of fatty acid ethanolamides (FAEs), contributing to the downstream events in the ischemic cascade. We therefore studied release of FAEs such as anandamide, palmitylethanolamide (PEA), and oleylethanolamide (OEA) in the brain of a patient suffering from malignant hemispheric infarction treated with hypothermia.. A patient with life-threatening hemispheric stroke was treated with moderate hypothermia (33 degrees C) that was maintained for 3 days, followed by a 3-day rewarming period. Microdialysis was applied to measure glutamate, lactate, and glycerol by using a microdialysis analyzer. FAEs were measured by microdialysis coupled with high-performance liquid chromatography/mass spectrometry. Release of neuroprotective fatty amides occurred within the first day after ischemia and reached high concentrations for all 3 substances in tissue surrounding the primary ischemic lesion: anandamide up to 42 pmol/mL, PEA up to 120 pmol/mL, and OEA up to 242 pmol/mL. There was a significant correlation with elevation of lactate as early marker for the hypoxic insult.. This is the first report demonstrating release of FAEs in vivo during human stroke and may suggest contribution of the FAE signaling system to the pathophysiological events after ischemia.

Topics: Aged; Amides; Arachidonic Acids; Brain; Brain Chemistry; Brain Ischemia; Endocannabinoids; Ethanolamines; Extracellular Space; Glutamic Acid; Glycerol; Hemiplegia; Humans; Hypothermia, Induced; Lactic Acid; Male; Microdialysis; Monitoring, Physiologic; Oleic Acid; Oleic Acids; Palmitic Acids; Polyunsaturated Alkamides; Sleep Stages; Stroke