sphingosine-phosphorylcholine and Subarachnoid-Hemorrhage

The sphingosylphosphorylcholine-Rho-kinase pathway plays an important role in Ca(2+) sensitization of vascular smooth muscle contraction. Eicosapentaenoic acid (EPA) inhibits sphingosylphosphorylcholine -Rho-kinase-activated Ca(2+)-sensitization in vitro and in subarachnoid hemorrhage (SAH) models in vivo and has also been shown to inhibit the occurrence of cerebral vasospasm (CIV) after the onset of SAH in a prospective, nonrandomized study. The current prospective, multicenter, randomized study was performed to confirm the preventive effects of EPA on CIV in patients with SAH.. The trial population comprised 162 patients who underwent surgical clipping within 72 hours of the onset of SAH. Of these patients, 81 received 2700 mg/day EPA from the day after surgery until day 30 (EPA group), and 81 did not receive EPA (control group). The primary end point was the occurrence of symptomatic vasospasm (SV) or cerebral infarction caused by CIV.. The occurrences of SV (15% vs. 30%; P = 0.022) and CIV (7% vs. 21%; P = 0.012) were lower in the EPA group. Multivariate analysis revealed an adjusted odds ratio of 0.39 (95% confidence interval, 0.17-0.89; P = 0.028) for SV inhibition by EPA and 0.27 (95% confidence interval, 0.09-0.72; P = 0.012) for CIV inhibition.. These results indicate that oral EPA reduces the frequency of SV and CIV after the onset of aneurysmal SAH.

Topics: Aged; Arachidonic Acid; Cardiovascular Agents; Combined Modality Therapy; Eicosapentaenoic Acid; Female; Humans; Male; Middle Aged; Odds Ratio; Phosphorylcholine; Prospective Studies; rho-Associated Kinases; Signal Transduction; Sphingosine; Subarachnoid Hemorrhage; Treatment Outcome; Vasospasm, Intracranial

Inflammation has an important function in the development of cerebral vasospasm after subarachnoid hemorrhage (SAH); however, the mediators of this inflammatory response have not been clearly identified. In this study, we have investigated the potential function of two sphingolipids, which occur naturally in plasma and serum, sphingosylphosphorylcholine (SPC) and sphingosine 1-phosphate (S1P), to act as proinflammatory mediators in cerebral artery vascular smooth muscle (VSM) cells. In rat cerebral arteries, SPC but not S1P activated p38 mitogen-activated protein kinase (MAPK). Using transcription factor arrays, two proinflammatory transcription factors activated by SPC in cerebral arteries were identified--nuclear factor-κB and CCAAT-enhancer-binding protein. Both these transcription factors were activated by SPC in a p38MAPK-dependent manner. To determine whether this contributed to vascular inflammation, an inflammatory protein array was performed, which showed that SPC increased release of the chemokine monocyte chemoattractant protein-1 (MCP-1) in cultured rat VSM cells. This increase in MCP-1 expression was confirmed in cerebral arteries. The S1P did not increase MCP-1 release. Taken together, our results suggest that SPC, but not S1P, can act as a proinflammatory mediator in cerebral arteries. This may contribute to inflammation observed after SAH and may be part of the initiating event in vasospasm.

Topics: Animals; Blood Platelets; Blotting, Western; Cells, Cultured; Cerebral Arteries; Chemokine CCL2; Electrophoretic Mobility Shift Assay; Enzyme Activation; Enzyme-Linked Immunosorbent Assay; Fluorescent Antibody Technique; Inflammation; Inflammation Mediators; Lysophospholipids; Male; Muscle, Smooth, Vascular; NF-kappa B; p38 Mitogen-Activated Protein Kinases; Phosphorylcholine; Rats; Rats, Sprague-Dawley; Sphingosine; Subarachnoid Hemorrhage; Transcription Factors; Up-Regulation; Vasospasm, Intracranial

This study investigates the role of sphingosylphosphorylcholine (SPC) in the mechanisms underlying cerebral vasospasm after subarachnoid hemorrhage (SAH). The levels of SPC were measured in cerebrospinal fluid (CSF) of patients with SAH and also in an experimental canine model. CSF samples were collected from 11 patients with SAH, and from dogs that had received an injection of SPC into the cisterna magna to examine SPC kinetics in the CSF. SPC was assayed using solid-phase extraction and triple quadrupole mass spectrometry. The SPC concentrations in SAH patients on days 3, 8, and 14 after the onset of SAH were significantly higher than those in normal CSF. In the canine model, rapid dilution of SPC in CSF was observed. In combination with data from previous studies, these results suggest that SPC is involved in the development of cerebral vasospasm. Rapid dilution of SPC in CSF suggests that SPC is released into CSF at higher concentrations than those measured in the present study.

Topics: Aged; Aged, 80 and over; Analysis of Variance; Animals; Calibration; Chromatography, High Pressure Liquid; Dogs; Female; Humans; Kinetics; Male; Mass Spectrometry; Middle Aged; Phosphorylcholine; Regression Analysis; Solid Phase Extraction; Sphingosine; Subarachnoid Hemorrhage

Rho-kinase (ROK)-mediated Ca2+ sensitization of vascular smooth muscle (VSM) contraction plays a pivotal role in cerebral vasospasm (CV). We previously demonstrated that sphingosylphosphorylcholine (SPC) induces Ca2+ sensitization through sequential activation of the Src family protein tyrosine kinases (Src-PTKs) and ROK in vitro, and that Ca2+ sensitization is inhibited by eicosapentaenoic acid (EPA) through the selective inactivation of Src-PTK. In this study, we examined whether SPC induced CV in vivo, and, if it did, whether EPA would inhibit CV, as induced by SPC or in an in vivo model of subarachnoid hemorrhage (SAH).. Changes in the diameter of the canine basilar artery were investigated by angiography after administering SPC into the cisterna magna. Then, Y27632, a specific Rho-kinase inhibitor, or EPA was injected intracisternally and the effects of both agents were investigated. In another experiment using a single-hemorrhage model, Y27632 or EPA was injected on day 7 after SAH and the changes in the diameter of the canine basilar artery were investigated.. At cerebrospinal fluid concentrations of 100 and 300 micromol/l, SPC induced severe vasoconstriction (maximum vasoconstriction by SPC (100 micromol/l): 61.8 +/- 8.2%), which was markedly reversed by Y27632 (96.3 +/- 4.4%) or EPA (92.6 +/- 12.8%). SAH caused severe vasospasm on day 7 (67.6 +/- 7.8%), which was significantly blocked by Y27632 (95.5 +/- 10.6%) or EPA (90.0 +/- 4.4%).. SPC is a novel mediator of ROK-induced CV in vivo. The inhibition of CV induced by SPC or after SAH by EPA suggests beneficial roles of EPA in the treatment of CV. Our findings are compatible with the notion that the SPC-ROK pathway may be involved in CV.

Topics: Animals; Basilar Artery; Benzopyrans; Cerebral Angiography; Cisterna Magna; Disease Models, Animal; Dogs; Eicosapentaenoic Acid; Female; Injections; Male; Phosphorylcholine; Protein Kinase Inhibitors; rho-Associated Kinases; Signal Transduction; Sphingosine; Subarachnoid Hemorrhage; Time Factors; Vasoconstriction; Vasodilator Agents; Vasospasm, Intracranial