Immunomodulatory lipid mediator profiling of cerebrospinal fluid following surgery in older adults.

Arachidonic acid (AA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA) derived lipids play key roles in initiating and resolving inflammation. Neuro-inflammation is thought to play a causal role in perioperative neurocognitive disorders, yet the role of these lipids in the human central nervous system in such disorders is unclear. Here we used liquid chromatography-mass spectrometry to quantify AA, DHA, and EPA derived lipid levels in non-centrifuged cerebrospinal fluid (CSF), centrifuged CSF pellets, and centrifuged CSF supernatants of older adults obtained before, 24 h and 6 weeks after surgery. GAGE analysis was used to determine AA, DHA and EPA metabolite pathway changes over time. Lipid mediators derived from AA, DHA and EPA were detected in all sample types. Postoperative lipid mediator changes were not significant in non-centrifuged CSF (p > 0.05 for all three pathways). The AA metabolite pathway showed significant changes in centrifuged CSF pellets and supernatants from before to 24 h after surgery (p = 0.0000247, p = 0.0155 respectively), from before to 6 weeks after surgery (p = 0.0000497, p = 0.0155, respectively), and from 24 h to 6 weeks after surgery (p = 0.0000499, p = 0.00363, respectively). These findings indicate that AA, DHA, and EPA derived lipids are detectable in human CSF, and the AA metabolite pathway shows postoperative changes in centrifuged CSF pellets and supernatants.

A novel, fast and sensitive supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS) method for analysis of arachidonic acid metabolites.

The development of a rapid, sensitive and reliable method for the quantification of bioactive arachidonic acid metabolites (AA-metabolites) in biological samples is quite challenging due to the minute concentration, short half-life and their structural complexity arising from different isomers. In this study, a simple, fast and environmentally friendly supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS) method was developed and validated for simultaneous measurement of five (PGD2, PGE2, PGF2α, 6KetoPGF1α and LTB4) AA-metabolites in biological samples. These analytes were extracted by protein precipitation followed by separation and quantification. The analysis was completed within 3 minutes. The matrix matched linear calibration ranged from 0.5-100 ng mL-1 (r2 ≥ 0.995), whilst, the limit of quantification of PGD2, PGE2, PGF2α, and LTB4 was 0.5 ng mL-1 and was 2.5 ng mL-1 for 6KetoPGF1α. The interday and intraday precisions of the method were less than 15% while the accuracy of most of the analytes varied between 83 and 109%. Finally, as a proof of concept, the method was successfully applied for the determination of eicosanoids in human samples, which expands the possibility to explore physiological states, disease phenotypes, and novel biomarkers.

Arachidonic acid pathway alterations in cerebrospinal fluid of dogs with naturally occurring spinal cord injury.

BACKGROUND: Canine intervertebral disc πherniation causes a naturally-occurring spinal cord injury (SCI) that bears critical similarities to human SCI with respect to both injury pathomechanisms and treatment. As such, it has tremendous potential to enhance our understanding of injury biology and the preclinical evaluation of novel therapies. Currently, there is limited understanding of the role of arachidonic acid metabolites in canine SCI. RESULTS: The CSF concentrations of PLA2 and PGE2 were higher in SCI dogs compared to control dogs (p = 0.0370 and 0.0273, respectively), but CSF LCT4 concentration in SCI dogs was significantly lower than that in control dogs (p < 0.0001). Prostaglandin E2 concentration in the CSF was significantly and positively associated with increased severity of SCI at the time of sampling (p = 0.041) and recovery 42 days post-injury (p = 0.006), as measured by ordinal behavioral scores. CONCLUSION: Arachidonic acid metabolism is altered in dogs with SCI, and these data suggest that these AA metabolites reflect injury severity and recovery, paralleling data from other model systems.

A prospective, multicenter, randomized study of the efficacy of eicosapentaenoic acid for cerebral vasospasm: the EVAS study.

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: These results indicate that oral EPA reduces the frequency of SV and CIV after the onset of aneurysmal SAH.

Lipid mediators in cerebral spinal fluid of traumatic brain injured patients.

BACKGROUND: Enzymatic and nonenzymatic oxidation of polyunsaturated fatty acids leads to the formation of biologically active products known as lipid mediators. In the brain, lipid mediators play an important role in supporting homeostasis and normal function. Thus, levels of these metabolites in normal and pathologic conditions in the brain are particularly relevant in understanding the transition to disease. METHODS: In this study, liquid chromatography tandem mass spectrometry was used to analyze lipid mediators in cerebrospinal fluid (CSF) of controls and traumatic brain injured (TBI) patients. RESULTS: Our results showed that the levels of arachidonic acid (AA), docosahexaenoic acid (DHA), 5- and 12- eicosatetraenoic acid (HETE) were significantly increased in the CSF of TBI patients. The magnitude of increase was 10-fold for AA, DHA, and 5-HETE and 17-fold for 12-HETE. Prostaglandins and leukotrienes were not detected in CSF of either control or brain injured patients. Furthermore, this study found that isoprostanes and thromboxanes are present in CSF of brain injured patients. CONCLUSIONS: This study clearly shows that certain lipid mediators accumulate in the CSF of TBI patient. This study also suggests the potential use of DHA, AA, 5- and 12-HETE as biochemical markers of brain injury and to monitor the impact of interventions.

Rapid, simultaneous quantitation of mono and dioxygenated metabolites of arachidonic acid in human CSF and rat brain.

Currently, there are few biomarkers to predict the risk of symptomatic cerebral vasospasm (SV) in subarachnoid hemorrhage (SAH) patients. Mono and dioxygenated arachidonic acid metabolites, involved in the pathogenesis of ischemic injury, may serve as indicators of SV. This study developed a quantitative UPLC-MS/MS method to simultaneously measure hydroxyeicosatetraenoic acid (HETE), dihydroxyeicosatrienoic acid (DiHETrE), and epoxyeicosatrienoic acid (EET) metabolites of arachidonic acid in cerebrospinal fluid (CSF) samples of SAH patients. Additionally, we determined the recovery of these metabolites from polyvinylchloride (PVC) bags used for CSF collection. Linear calibration curves ranging from 0.208 to 33.3 ng/ml were validated. The inter-day and intra-day variance was less than 15% at most concentrations with extraction efficiency greater than 73%. The matrix did not affect the reproducibility and reliability of the assay. In CSF samples, peak concentrations of 8,9-DiHETrE, 20-HETE, 15-HETE, and 12-HETE ranged from 0.293 to 24.9 ng/ml. In rat brain cortical tissue samples, concentrations of 20-, 15-, 12-HETE, 8,9-EET, and 14,15-, 11,12-DiHETrE ranged from 0.57 to 23.99 pmol/g wet tissue. In rat cortical microsomal incubates, all 10 metabolites were measured with formation rates ranging from 0.03 to 7.77 pmol/mg/min. Furthermore, 12-HETE and EET metabolites were significantly altered by contact with PVC bags at all time points evaluated. These data demonstrate that the simultaneous measurement of these compounds in human CSF and rat brain can be achieved with a UPLC-MS/MS system and that this method is necessary for evaluation of these metabolites as potential quantitative biomarkers in future clinical trials.

Opposite changes in predominantly docosahexaenoic acid (DHA) in cerebrospinal fluid and red blood cells from never-medicated first-episode psychotic patients.

Variable levels of essential polyunsaturated fatty acids (EPUFAs) reported in schizophrenia are likely due to differences in age, sex, ethnicity, diet, life style and treatments. The present study examined the EPUFAs levels in plasma, RBC and CSF in never-medicated first-episode psychotic patients and normal controls matched for ethnicity, diet and life style. The plasma EPUFAs levels were similar in both groups. Among the EPUFAs enriched in the brain, predominantly docosahexaenoic acid (DHA) levels were lower in RBC (p=<0.01) whereas higher in CSF (p=<0.01) in male>female patients. This altered DHA metabolism may provide clues for neuropathology and treatment of schizophrenia.

Evidence for a role of the arachidonic acid cascade in affective disorders: a review.

The treatment of affective disorders continues to present significant clinical challenges, notwithstanding the existence of available mood stabilizers and antidepressants. These difficulties include incomplete response, relapse, and intolerable medication side effects. Fundamental to the therapeutic impasse is incomplete knowledge concerning the neurobiology of mood disorders. Although some relevant biochemical pathways have been identified, including abnormalities of monoamine neurotransmission and of immunological functioning, a fuller understanding is likely to embrace other interrelated pathways. Arachidonic acid (AA) and prostaglandins (PGs) are important second messengers in the central nervous system that participate in signal transduction, inflammation and other vital processes. Their release, turnover, and metabolism represent the 'arachidonic acid cascade'. A significant body of diverse clinical and preclinical research suggests that the AA cascade may be important in affective states. This paper reviews the literature describing the association of affective illness with AA and its metabolites. Possible links between this and other prevailing hypotheses are considered, and implications for further research and for treatment are discussed.

Free fatty acids in cerebrospinal fluids from patients with traumatic brain injury.

Free fatty acid (FFA) concentrations in cerebrospinal fluid (CSF) are recognized as markers of brain damage in animal studies. There is, however, relatively little information regarding FFA concentrations in human CSF in normal and pathological conditions. The present study examined FFA concentrations in CSF from 15 patients with traumatic brain injury (TBI) and compared the data with values obtained from 73 contemporary controls. Concentrations of specific FFAs from TBI patients, obtained within 48 h of the insult were significantly greater than those in the control group (arachidonic, docosahexaenoic and myristic, P<0.001; oleic, palmitic, P<0.01; linoleic, P<0.05). Higher concentrations of total polyunsaturated fatty acids (P<0.001) and of arachidonic, myristic and palmitic acids measured individually in CSF (P<0.01) obtained 1 week after the insult were associated with a worse outcome at the time of hospital discharge using the Glasgow Outcome Scale. This preliminary investigation suggests that CSF FFA concentrations may be useful as a predictive marker of outcome following TBI.

Free fatty acids in human cerebrospinal fluid following subarachnoid hemorrhage and their potential role in vasospasm: a preliminary observation.

OBJECT: The mechanisms leading to vasospasm following subarachnoid hemorrhage (SAH) remain unclear. Accumulation in cerebrospinal fluid (CSF) of free fatty acids (FFAs) may play a role in the development of vasospasm; however, in no previous study have concentrations of FFAs in CSF been examined after SAH. METHODS: We collected samples of CSF from 20 patients with SAH (18 cases of aneurysmal SAH and two cases of spontaneous cryptogenic SAH) and used a high-performance liquid chromatography assay to determine the FFA concentrations in these samples. We then compared these findings with FFA concentrations in the CSF of control patients. All FFA concentrations measured 24 hours after SAH were significantly greater than control concentrations (p < 0.01 for palmitic acid and < 0.001 for all other FFAs). All measured FFAs remained elevated for the first 48 hours after SAH (p < 0.05 for linoleic acid, p < 0.01 for palmitic acid, and p < 0.001 for the other FFAs). After 7 days, a second elevation in all FFAs was observed (p < 0.05 for linoleic acid, p < 0.01 for palmitic acid, and p < 0.001 for the other FFAs). Samples of CSF collected within 48 hours after SAH from patients in whom angiography and clinical examination confirmed the development of vasospasm after SAH were found to have significantly higher concentrations of arachidonic, linoleic, and palmitic acids than samples collected from patients in whom vasospasm did not develop (p < 0.05). CONCLUSIONS: Following SAH, all FFAs are initially elevated. A secondary elevation occurs between 8 and 10 days after SAH. This study provides preliminary evidence of FFA elevation following SAH and of a potential role for FFAs in SAH-induced vasospasm. A prospective study is warranted to determine if CSF concentrations of FFAs are predictive of vasospasm.