Associations of ApoE4 status and DHA supplementation on plasma and CSF lipid profiles and entorhinal cortex thickness.

Apolipoprotein ε allele 4 (APOE4) influences the metabolism of polyunsaturated fatty acids (PUFAs) such as docosahexaenoic acid (DHA). The entorhinal cortex (EC) in the brain is affected early in Alzheimer's disease and is rich in DHA. The purpose of this study is to identify the effect of APOE4 and DHA lipid species on the EC. Plasma and cerebrospinal fluid (CSF) lipidomic measurements were obtained from the DHA Brain Delivery Pilot, a randomized clinical trial of DHA supplementation (n = 10) versus placebo (n = 12) for six months in nondemented older adults stratified by APOE4 status. Wild-type C57B6/J mice were fed a high or low DHA diet for 6 months followed by plasma and brain lipidomic analysis. Levels of phosphatidylcholine DHA (PC 38:6) and cholesterol ester DHA (CE 22:6) had the largest increases in CSF following supplementation (P < 0.001). DHA within triglyceride (TG) lipids in CSF strongly correlated with corresponding plasma TG lipids, and differed by APOE4, with carriers having a lower increase than noncarriers. Changes in plasma PC DHA had the strongest association with changes in EC thickness in millimeters, independent of APOE4 status (P = 0.007). In mice, a high DHA diet increased PUFAs within brain lipids. Our findings demonstrate an exchange of DHA at the CSF-blood barrier and into the brain within all lipid species with APOE having the strongest effect on DHA-containing TGs. The correlation of PC DHA with EC suggests a functional consequence of DHA accretion in high density lipoprotein for the brain.

Biomarkers - Part 1.

BACKGROUND: The CSF amyloid to tau ratio can isolate cognitively healthy participants into normal Aß42/tau (CH-NAT) or a pathological Aß42/tau (CH-PAT) with a low or high risk of cognitive decline, respectively. We aim to determine if plasma Aß42/tau ratios can differentiate CH-NAT from CH-PAT participants. METHOD: Study participants (> 65 years of age) were recruited, and demographic, neurological, and neuropsychological data were obtained in an ongoing HMRI Brain Aging study. Overnight fasting plasma and CSF were collected within a month of examination, and the levels of Aß38, Aß40, Aß42 (MSD 6E10 kit), and total tau were quantified using the MSD electrochemiluminescence platform. Differences in fluid biomarker levels and the plasma ratios (n = 55) and CSF ratios (Aß42/Aß40, n = 41, Aß42/tau, n = 55) were determined using nonparametric student t-test and correlations using a Spearman test. RESULT: Aß40 and Aß42 levels were higher (15-18-fold, and 10-14-fold, respectively), while tau levels are 8-13-fold higher in CSF than in plasma. Plasma and CSF Aß40 were not distinct in CH-NAT compared with CH-PAT. In contrast, Aß42 levels were 30.9% lower in CH-PAT (16.3 ± 18.3 pg/ml) compared with CH-NAT plasma (23.6 ± 26.4 pg/mL) (p < 0.05). CSF Aß42 levels in CH-PAT (171.6 ± 124.6 pg/mL) were lower by 47.6% compared with CH-NAT (327.6 ± 182.6 pg/ml) (p < 0.0001). The Aß42/Aß40 ratio was significantly lower in both plasma and CSF (Table 1A). Similarly, the Aß42/tau ratio was significantly lower in plasma and CSF (Table 1B). Individually, plasma levels of Aß42 and tau did not correlate with CSF levels. However, the ratio of Aß42 to total tau in plasma significantly correlated with the CSF ratios (Spearman r = 0.36, p = 0.0071). Finally, CSF Aß42/Aß40 ratio correlated with Aß42/tau ratio for all samples, CH (n = 100) and MCI (n = 35) (Fig. 1). CONCLUSION: While not as robust as CSF ratios, plasma Aß42/Aß40 and Aß42/tau ratios can isolate cognitively healthy participants with lower risk from participants with a higher risk of cognitive decline. Thus, plasma represents a less invasive medium for the biomarker classification of aging participants.

Nutritional metabolism and cerebral bioenergetics in Alzheimer's disease and related dementias.

Disturbances in the brain's capacity to meet its energy demand increase the risk of synaptic loss, neurodegeneration, and cognitive decline. Nutritional and metabolic interventions that target metabolic pathways combined with diagnostics to identify deficits in cerebral bioenergetics may therefore offer novel therapeutic potential for Alzheimer's disease (AD) prevention and management. Many diet-derived natural bioactive components can govern cellular energy metabolism but their effects on brain aging are not clear. This review examines how nutritional metabolism can regulate brain bioenergetics and mitigate AD risk. We focus on leading mechanisms of cerebral bioenergetic breakdown in the aging brain at the cellular level, as well as the putative causes and consequences of disturbed bioenergetics, particularly at the blood-brain barrier with implications for nutrient brain delivery and nutritional interventions. Novel therapeutic nutrition approaches including diet patterns are provided, integrating studies of the gut microbiome, neuroimaging, and other biomarkers to guide future personalized nutritional interventions.

Evidence that blood-CSF barrier transport, but not inflammatory biomarkers, change in migraine, while CSF sVCAM1 associates with migraine frequency and CSF fibrinogen.

OBJECTIVE: Our objective is to explore whether blood-cerebrospinal fluid (CSF) barrier biomarkers differ in episodic migraine (EM) or chronic migraine (CM) from controls. BACKGROUND: Reports of blood-brain barrier and blood-cerebrospinal fluid barrier (BCSFB) disruption in migraine vary. Our hypothesis is that investigation of biomarkers associated with blood, CSF, brain, cell adhesion, and inflammation will help elucidate migraine pathophysiology. METHODS: We recruited 14 control volunteers without headache disorders and 42 individuals with EM or CM as classified using the International Classification of Headache Disorders, 3rd edition, criteria in a cross-sectional study located at our Pasadena and Stanford headache research centers in California. Blood and lumbar CSF samples were collected once from those diagnosed with CM or those with EM during two states: during a typical migraine, before rescue therapy, with at least 6/10 level of pain (ictal); and when migraine free for at least 48 h (interictal). The average number of headaches per month over the previous year was estimated by those with EM; this enabled comparison of biomarker changes between controls and three headache frequency groups: <2 per month, 2-14 per month, and CM. Blood and CSF biomarkers were determined using antibody-based methods. RESULTS: Antimigraine medication was only taken by the EM and CM groups. Compared to controls, the migraine group had significantly higher mean CSF-blood quotients of albumin (Qalb : mean ± standard deviation (SD): 5.6 ± 2.3 vs. 4.1 ± 1.9) and fibrinogen (Qfib mean ± SD: 1615 ± 99.0 vs. 86.1 ± 55.0). Mean CSF but not plasma soluble vascular cell adhesion molecule-1 (sVCAM-1) levels were significantly higher in those with more frequent migraine: (4.5 ng/mL ± 1.1 in those with <2 headache days a month; 5.5 ± 1.9 with 2-14 days a month; and 7.1 ± 2.9 in CM), while the Qfib ratio was inversely related to headache frequency. We did not find any difference in individuals with EM or CM from controls for CSF cell count, total protein, matrix metalloproteinase-9, soluble platelet-derived growth factor receptor ß, tumor necrosis factor-alpha, interferon-gamma, interleukin (IL)-6, IL-8, IL-10, or C-reactive protein. CONCLUSIONS: The higher Qalb and Qfib ratios may indicate that the transport of these blood-derived proteins is disturbed at the BCSFB in persons with migraine. These changes most likely occur at the choroid plexus epithelium, as there are no signs of typical endothelial barrier disruption. The most striking finding in this hypothesis-generating study of migraine pathophysiology is that sVCAM-1 levels in CSF may be a biomarker of higher frequency of migraine and CM. An effect from migraine medications cannot be excluded, but there is no known mechanism to suggest they have a role in altering the CSF biomarkers.

Severe Headache or Migraine History is Inversely Correlated With Dietary Sodium Intake: NHANES 1999-2004.

OBJECTIVE: We investigated whether dietary sodium intake from respondents of a national cross-sectional nutritional study differed by history of migraine or severe headaches. BACKGROUND: Several lines of evidence support a disruption of sodium homeostasis in migraine. DESIGN: Our analysis population was 8819 adults in the 1999-2004 National Health and Nutrition Examination Survey (NHANES) with reliable data on diet and headache history. We classified respondents who reported a history of migraine or severe headaches as having probable history of migraine. To reduce the diagnostic conflict from medication overuse headache, we excluded respondents who reported taking analgesic medications. Dietary sodium intake was measured using validated estimates of self-reported total grams of daily sodium consumption and was analyzed as the residual value from the linear regression of total grams of sodium on total calories. Multivariable logistic regression that accounted for the stratified, multistage probability cluster sampling design of NHANES was used to analyze the relationship between migraine and dietary sodium. RESULTS: Odds of probable migraine history decreased with increasing dietary sodium intake (odds ratio = 0.93, 95% confidence interval = 0.87, 1.00, P = .0455). This relationship was maintained after adjusting for age, sex, and body mass index (BMI) with slightly reduced significance (P = .0505). In women, this inverse relationship was limited to those with lower BMI (P = .007), while in men the relationship did not differ by BMI. We likely excluded some migraineurs by omitting frequent analgesic users; however, a sensitivity analysis suggested little effect from this exclusion. CONCLUSIONS: This study is the first evidence of an inverse relationship between migraine and dietary sodium intake. These results are consistent with altered sodium homeostasis in migraine and our hypothesis that dietary sodium may affect brain extracellular fluid sodium concentrations and neuronal excitability.

Associations of Plasma Glutamatergic Metabolites with Alpha Desynchronization during Cognitive Interference and Working Memory Tasks in Asymptomatic Alzheimer's Disease.

Electroencephalogram (EEG) studies have suggested compensatory brain overactivation in cognitively healthy (CH) older adults with pathological beta-amyloid(Aß42)/tau ratios during working memory and interference processing. However, the association between glutamatergic metabolites and brain activation proxied by EEG signals has not been thoroughly investigated. We aim to determine the involvement of these metabolites in EEG signaling. We focused on CH older adults classified under (1) normal CSF Aß42/tau ratios (CH-NATs) and (2) pathological Aß42/tau ratios (CH-PATs). We measured plasma glutamine, glutamate, pyroglutamate, and γ-aminobutyric acid concentrations using tandem mass spectrometry and conducted a correlational analysis with alpha frequency event-related desynchronization (ERD). Under the N-back working memory paradigm, CH-NATs presented negative correlations (r = ~-0.74--0.96, p = 0.0001-0.0414) between pyroglutamate and alpha ERD but positive correlations (r = ~0.82-0.95, p = 0.0003-0.0119) between glutamine and alpha ERD. Under Stroop interference testing, CH-NATs generated negative correlations between glutamine and left temporal alpha ERD (r = -0.96, p = 0.037 and r = -0.97, p = 0.027). Our study demonstrated that glutamine and pyroglutamate levels were associated with EEG activity only in CH-NATs. These results suggest cognitively healthy adults with amyloid/tau pathology experience subtle metabolic dysfunction that may influence EEG signaling during cognitive challenge. A longitudinal follow-up study with a larger sample size is needed to validate these pilot studies.

Alterations in cerebrospinal fluid glycerophospholipids and phospholipase A2 activity in Alzheimer's disease.

Our aim is to study selected cerebrospinal fluid (CSF) glycerophospholipids (GP) that are important in brain pathophysiology. We recruited cognitively healthy (CH), minimally cognitively impaired (MCI), and late onset Alzheimer's disease (LOAD) study participants and collected their CSF. After fractionation into nanometer particles (NP) and supernatant fluids (SF), we studied the lipid composition of these compartments. LC-MS/MS studies reveal that both CSF fractions from CH subjects have N-acyl phosphatidylethanolamine, 1-radyl-2-acyl-sn-glycerophosphoethanolamine (PE), 1-radyl-2-acyl-sn-glycerophosphocholine (PC), 1,2-diacyl-sn-glycerophosphoserine (PS), platelet-activating factor-like lipids, and lysophosphatidylcholine (LPC). In the NP fraction, GPs are enriched with a mixture of saturated, monounsaturated, and polyunsaturated fatty acid species, while PE and PS in the SF fractions are enriched with PUFA-containing molecular species. PC, PE, and PS levels in CSF fractions decrease progressively in participants from CH to MCI, and then to LOAD. Whereas most PC species decrease equally in LOAD, plasmalogen species account for most of the decrease in PE. A significant increase in the LPC-to-PC ratio and PLA2 activity accompanies the GP decrease in LOAD. These studies reveal that CSF supernatant fluid and nanometer particles have different GP composition, and that PLA2 activity accounts for altered GPs in these fractions as neurodegeneration progresses.

Phospholipase C activity increases in cerebrospinal fluid from migraineurs in proportion to the number of comorbid conditions: a case-control study.

BACKGROUND: Migraineurs are more often afflicted by comorbid conditions than those without primary headache disorders, though the linking pathophysiological mechanism(s) is not known. We previously reported that phosphatidylcholine-specific phospholipase C (PC-PLC) activity in cerebrospinal fluid (CSF) increased during migraine compared to the same individual's well state. Here, we examined whether PC-PLC activity from a larger group of well-state migraineurs is related to the number of their migraine comorbidities. METHODS: In a case-control study, migraineurs were diagnosed using International Headache Society criteria, and controls had no primary headache disorder or family history of migraine. Medication use, migraine frequency, and physician-diagnosed comorbidities were recorded for all participants. Lumbar CSF was collected between the hours of 1 and 5 pm, examined immediately for cells and total protein, and stored at -80°C. PC-PLC activity in thawed CSF was measured using a fluorometric enzyme assay. Multivariable logistic regression was used to evaluate age, gender, medication use, migraine frequency, personality scores, and comorbidities as potential predictors of PC-PLC activity in CSF. RESULTS: A total of 18 migraineurs-without-aura and 17 controls participated. In a multivariable analysis, only the number of comorbidities was related to PC-PLC activity in CSF, and only in migraineurs [parameter estimate (standard error) = 1.77, p = 0.009]. CONCLUSION: PC-PLC activity in CSF increases with increasing number of comorbidities in migraine-without-aura. These data support involvement of a common lipid signaling pathway in migraine and in the comorbid conditions.

An Association Between Saturated Fatty Acid-Containing Phosphatidylcholine in Cerebrospinal Fluid with Tau Phosphorylation.

BACKGROUND: Mechanistic studies in animal models implicate a role for saturated fatty acids in neurodegeneration, but validation of this finding in human studies is still lacking. OBJECTIVE: We investigated how cerebrospinal levels of sphingomyelins (SM) and phosphatidylcholine (PC)-containing saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids associate with total tau and phosphorylated tau (p-tau). METHODS: Cerebrospinal fluid (CSF) lipids were measured in two cohorts, a discovery and a confirmation cohort of older non-demented individuals from the University of Southern California and Huntington Medical Research Institutes cohorts. Lipid analysis was performed using hydrophilic interaction liquid chromatography, and individual PC and SM lipid species were measured using tandem mass spectrometry. In addition, CSF levels of Aß42, total tau, and p-tau-181 were measured using an MSD multiplex assay. RESULTS: The discovery cohort (n = 47) consisted of older individuals and more females compared to the confirmation cohort (n = 46). Notwithstanding the age and gender differences, and a higher p-tau, Aß42, and LDL-cholesterol in the discovery cohort, CSF concentrations of dipalmitoyl-PC (PC32a:0) were significantly associated with p-tau in both cohorts. Similarly, total saturated PC but not mono or polyunsaturated PCs correlated with p-tau concentrations in both cohorts. CONCLUSION: Saturated PC species in CSF associate with early markers of neurodegeneration and are potential early disease progression biomarkers. We propose mechanisms by which saturated PC may promote tau hyperphosphorylation.

Alpha desynchronization during Stroop test unmasks cognitively healthy individuals with abnormal CSF Amyloid/Tau.

Synaptic dysfunctions precede cognitive decline in Alzheimer's disease by decades, affect executive functions, and can be detected by quantitative electroencephalography (qEEG). We used quantitative electroencephalography combined with Stroop testing to identify changes of inhibitory controls in cognitively healthy individuals with an abnormal versus normal ratio of cerebrospinal fluid (CSF) amyloid/total-tau. We studied two groups of participants (60-94 years) with either normal (CH-NAT or controls, n = 20) or abnormal (CH-PAT, n = 21) CSF amyloid/tau ratio. We compared: alpha event-related desynchronization (ERD), alpha spectral entropy (SE), and their relationships with estimated cognitive reserve. CH-PATs had more negative occipital alpha ERD, and higher frontal and occipital alpha SE during low load congruent trials, indicating hyperactivity. CH-PATs demonstrated fewer frontal SE changes with higher load, incongruent Stroop testing. Correlations of alpha ERD with estimated cognitive reserve were significant in CH-PATs but not in CH-NATs. These results suggested compensatory hyperactivity in CH-PATs compared to CH-NATs. We did not find differences in alpha ERD comparisons with individual CSF amyloid(A), p-tau(T), total-tau(N) biomarkers.

Calcium-dependent cytosolic phospholipase A2 activation is implicated in neuroinflammation and oxidative stress associated with ApoE4.

BACKGROUND: Apolipoprotein E4 (APOE4) is associated with a greater response to neuroinflammation and the risk of developing late-onset Alzheimer's disease (AD), but the mechanisms for this association are not clear. The activation of calcium-dependent cytosolic phospholipase A2 (cPLA2) is involved in inflammatory signaling and is elevated within the plaques of AD brains. The relation between APOE4 genotype and cPLA2 activity is not known. METHODS: Mouse primary astrocytes, mouse and human brain samples differing by APOE genotypes were collected for measuring cPLA2 expression, phosphorylation, and activity in relation to measures of inflammation and oxidative stress. RESULTS: Greater cPLA2 phosphorylation, cPLA2 activity and leukotriene B4 (LTB4) levels were identified in ApoE4 compared to ApoE3 in primary astrocytes, brains of ApoE-targeted replacement (ApoE-TR) mice, and in human brain homogenates from the inferior frontal cortex of persons with AD dementia carrying APOE3/4 compared to APOE3/3. Higher phosphorylated p38 MAPK but not ERK1/2 was found in ApoE4 primary astrocytes and mouse brains than that in ApoE3. Greater cPLA2 translocation to cytosol was observed in human postmortem frontal cortical synaptosomes with recombinant ApoE4 than ApoE3 ex vivo. In ApoE4 astrocytes, the greater levels of LTB4, reactive oxygen species (ROS), and inducible nitric oxide synthase (iNOS) were reduced after cPLA2 inhibition. CONCLUSIONS: Our findings implicate greater activation of cPLA2 signaling system with APOE4, which could represent a potential drug target for mitigating the increased neuroinflammation with APOE4 and AD.

Sodium MRI in a rat migraine model and a NEURON simulation study support a role for sodium in migraine.

INTRODUCTION: Increased lumbar cerebrospinal fluid (CSF) sodium has been reported during migraine. We used ultra-high field MRI to investigate cranial sodium in a rat migraine model, and simulated the effects of extracellular sodium on neuronal excitability. METHODS: Behavioral changes in the nitroglycerin (NTG) rat migraine model were determined from von Frey hair withdrawal response and photography. Central sensitization was measured by counting cFos-immunoreactive cells in the trigeminal nucleus caudalis (TNC). Sodium was quantified in vivo by ultra-high field sodium MRI at 21 Tesla. Effects of extracellular sodium on neuronal excitability were modeled using NEURON software. RESULTS: NTG decreased von Frey withdrawal threshold (p=0.0003), decreased eyelid vertical height:width ratio (p<0.0001), increased TNC cFos stain (p<0.0001), and increased sodium between 7.5 and 17% in brain, intracranial CSF, and vitreous humor (p<0.05). Simulated neurons exposed to higher sodium have more frequent and earlier spontaneous action potentials, and corresponding earlier sodium and potassium currents. CONCLUSIONS: In the rat migraine model, sodium rises to levels that increase neuronal excitability. We propose that rising sodium in CSF surrounding trigeminal nociceptors increases their excitability and causes pain and that rising sodium in vitreous humor increases retinal neuronal excitability and causes photosensitivity.

Cerebrospinal fluid phospholipase C activity increases in migraine.

BACKGROUND: Adrenaline, serotonin, cannabinoid and estrogen receptors are involved in migraine pathophysiology. The signaling of these receptors change phosphatidylcholine-specific phospholipase C (PC-PLC) activity, but there have been no reported PC-PLC studies in migraine. METHODS: We identified PC-PLC activity in blood and cerebrospinal fluid (CSF), and quantified it in samples from ictal and interictal migraineurs without aura and healthy controls. RESULTS: Pre-incubation with a specific PC-PLC inhibitor, D609, inhibited enzyme activity (p < .0001) and confirms its presence in CSF. PC-PLC activity was higher in the CSF from ictal migraineurs compared to controls (mean relative fluorescence unit [RFU]/µg/min [standard deviation, SD] 13.1 [3.07] vs. 9.3 [1.97]; p = .002) and, in a paired analysis, in migraineurs during ictal compared to interictal states (11.7 [1.6] vs. 7.9 [1.5]; p = .02). CSF PC-PLC activity in the ictal state correlated negatively with migraine frequency (r = -0.82). Plasma PC-PLC activity was 250-300 times less than in CSF and did not increase in migraine, implicating the brain as the source of the CSF enzyme changes. CONCLUSION: This is the first report of PC-PLC activity in CSF and of its alteration in migraine. We propose that these PC-PLC changes in CSF reflect the overall receptor fluctuations in migraine.

Plasma Lipolysis and Changes in Plasma and Cerebrospinal Fluid Signaling Lipids Reveal Abnormal Lipid Metabolism in Chronic Migraine.

BACKGROUND: Lipids are a primary storage form of energy and the source of inflammatory and pain signaling molecules, yet knowledge of their importance in chronic migraine (CM) pathology is incomplete. We aim to determine if plasma and cerebrospinal fluid (CSF) lipid metabolism are associated with CM pathology. METHODS: We obtained plasma and CSF from healthy controls (CT, n = 10) or CM subjects (n = 15) diagnosed using the International Headache Society criteria. We measured unesterified fatty acid (UFA) and esterified fatty acids (EFAs) using gas chromatography-mass spectrometry. Glycerophospholipids (GP) and sphingolipid (SP) levels were determined using LC-MS/MS, and phospholipase A2 (PLA2) activity was determined using fluorescent substrates. RESULTS: Unesterified fatty acid levels were significantly higher in CM plasma but not in CSF. Unesterified levels of five saturated fatty acids (SAFAs), eight monounsaturated fatty acids (MUFAs), five ω-3 polyunsaturated fatty acids (PUFAs), and five ω-6 PUFAs are higher in CM plasma. Esterified levels of three SAFAs, eight MUFAs, five ω-3 PUFAs, and three ω-6 PUFAs, are higher in CM plasma. The ratios C20:4n-6/homo-γ-C20:3n-6 representative of delta-5-desaturases (D5D) and the elongase ratio are lower in esterified and unesterified CM plasma, respectively. In the CSF, the esterified D5D index is lower in CM. While PLA2 activity was similar, the plasma UFA to EFA ratio is higher in CM. Of all plasma GP/SPs detected, only ceramide levels are lower (p = 0.0003) in CM (0.26 ± 0.07%) compared to CT (0.48 ± 0.06%). The GP/SP proportion of platelet-activating factor (PAF) is significantly lower in CM CSF. CONCLUSIONS: Plasma and CSF lipid changes are consistent with abnormal lipid metabolism in CM. Since plasma UFAs correspond to diet or adipose tissue levels, higher plasma fatty acids and UFA/EFA ratios suggest enhanced adipose lipolysis in CM. Differences in plasma and CSF desaturases and elongases suggest altered lipid metabolism in CM. A lower plasma ceramide level suggests reduced de novo synthesis or reduced sphingomyelin hydrolysis. Changes in CSF PAF suggest differences in brain lipid signaling pathways in CM. Together, this pilot study shows lipid metabolic abnormality in CM corresponding to altered energy homeostasis. We propose that controlling plasma lipolysis, desaturases, elongases, and lipid signaling pathways may relieve CM symptoms.

Task switching reveals abnormal brain-heart electrophysiological signatures in cognitively healthy individuals with abnormal CSF amyloid/tau, a pilot study.

Electroencephalographic (EEG) alpha oscillations have been related to heart rate variability (HRV) and both change in Alzheimer's disease (AD). We explored if task switching reveals altered alpha power and HRV in cognitively healthy individuals with AD pathology in cerebrospinal fluid (CSF) and whether HRV improves the AD pathology classification by alpha power alone. We compared low and high alpha event-related desynchronization (ERD) and HRV parameters during task switch testing between two groups of cognitively healthy participants classified by CSF amyloid/tau ratio: normal (CH-NAT, n = 19) or pathological (CH-PAT, n = 27). For the task switching paradigm, participants were required to name the color or word for each colored word stimulus, with two sequential stimuli per trial. Trials include color (cC) or word (wW) repeats with low load repeating, and word (cW) or color switch (wC) for high load switching. HRV was assessed for RR interval, standard deviation of RR-intervals (SDNN) and root mean squared successive differences (RMSSD) in time domain, and low frequency (LF), high frequency (HF), and LF/HF ratio in frequency domain. Results showed that CH-PATs compared to CH-NATs presented: 1) increased (less negative) low alpha ERD during low load repeat trials and lower word switch cost (low alpha: p = 0.008, Cohen's d = -0.83, 95% confidence interval -1.44 to -0.22, and high alpha: p = 0.019, Cohen's d = -0.73, 95% confidence interval -1.34 to -0.13); 2) decreasing HRV from rest to task, suggesting hyper-activated sympatho-vagal responses. 3) CH-PATs classification by alpha ERD was improved by supplementing HRV signatures, supporting a potentially compromised brain-heart interoceptive regulation in CH-PATs. Further experiments are needed to validate these findings for clinical significance.

Calcium-dependent cytosolic phospholipase A2 activation is implicated in neuroinflammation and oxidative stress associated with ApoE4.

BACKGROUND: Apolipoprotein E4 (APOE4) is associated with a greater response to neuroinflammation and the risk of developing late-onset Alzheimer's disease (AD), but the mechanisms for this association are not clear. The activation of calcium-dependent cytosolic phospholipase A2 (cPLA2) is involved in inflammatory signaling and is elevated within the plaques of AD brains. The relation between APOE4 genotype and cPLA2 activity is not known. METHODS: Mouse primary astrocytes, mouse and human brain samples differing by APOE genotypes were collected for measuring cPLA2 expression, phosphorylation, and activity in relation to measures of inflammation and oxidative stress. RESULTS: Greater cPLA2 phosphorylation, cPLA2 activity and leukotriene B4 (LTB4) levels were identified in ApoE4 compared to ApoE3 in primary astrocytes, brains of ApoE-targeted replacement (ApoE-TR) mice, and in human brain homogenates from the inferior frontal cortex of patients with AD carrying APOE3/E4 compared to APOE3/E3. Greater cPLA2 phosphorylation was also observed in human postmortem frontal cortical synaptosomes and primary astrocytes after treatment with recombinant ApoE4 ex vivo. In ApoE4 astrocytes, the greater levels of LTB4, reactive oxygen species (ROS), and inducible nitric oxide synthase (iNOS) were reduced after cPLA2 inhibition. CONCLUSIONS: Our findings implicate greater activation of cPLA2 signaling system with APOE4, which could represent a potential drug target for mitigating the increased neuroinflammation with APOE4 and AD.

Metabolic Evidence Rather Than Amounts of Red or Processed Meat as a Risk on Korean Colorectal Cancer.

The incidence of colorectal cancer (CRC) has increased in Korea, a newly-industrialized Asian country, with the dramatic increase of meat intake. To assess the risks of red or processed meat consumption on CRC, we performed a case-control study with biological monitoring of urinary1-OHP, PhIP, and MeIQx for the meat exposure; dG-C8 MeIQx and dG-C8 PhIP for HCA-induced DNA adducts; and homocysteine and C-reactive protein (CRP) in blood as well as malondialdehyde (MDA) and 31fatty acids in urine for inflammation and lipid alteration. We further analyzed global DNA methylation and expression of 15 CRC-related genes. As a result, the consumption of red or processed meat was not higher in the cases than in the controls. However, urinary MeIQx and PhIP were associated with the intake of red meat and urinary 1-OHP. MDA and multiple fatty acids were related to the exposure biomarkers. Most of the 31 fatty acids and multiple saturated fatty acids were higher in the cases than in the controls. Finally, the cases showed upregulation of PTGS2, which is related to pro-inflammatory fatty acids. This study describes indirect mechanisms of CRC via lipid alteration with a series of processes including exposure to red meat, alteration of fatty acids, and relevant gene expression.

Cerebrospinal fluid sodium rhythms.

BACKGROUND: Cerebrospinal fluid (CSF) sodium levels have been reported to rise during episodic migraine. Since migraine frequently starts in early morning or late afternoon, we hypothesized that natural sodium chronobiology may predispose susceptible persons when extracellular CSF sodium increases. Since no mammalian brain sodium rhythms are known, we designed a study of healthy humans to test if cation rhythms exist in CSF. METHODS: Lumbar CSF was collected every ten minutes at 0.1 mL/min for 24 h from six healthy participants. CSF sodium and potassium concentrations were measured by ion chromatography, total protein by fluorescent spectrometry, and osmolarity by freezing point depression. We analyzed cation and protein distributions over the 24 h period and spectral and permutation tests to identify significant rhythms. We applied the False Discovery Rate method to adjust significance levels for multiple tests and Spearman correlations to compare sodium fluctuations with potassium, protein, and osmolarity. RESULTS: The distribution of sodium varied much more than potassium, and there were statistically significant rhythms at 12 and 1.65 h periods. Curve fitting to the average time course of the mean sodium of all six subjects revealed the lowest sodium levels at 03.20 h and highest at 08.00 h, a second nadir at 09.50 h and a second peak at 18.10 h. Sodium levels were not correlated with potassium or protein concentration, or with osmolarity. CONCLUSION: These CSF rhythms are the first reports of sodium chronobiology in the human nervous system. The results are consistent with our hypothesis that rising levels of extracellular sodium may contribute to the timing of migraine onset. The physiological importance of sodium in the nervous system suggests that these rhythms may have additional repercussions on ultradian functions.

Capillary endothelial Na(+), K(+), ATPase transporter homeostasis and a new theory for migraine pathophysiology.

BACKGROUND: Cerebrospinal fluid sodium concentration ([Na(+)](csf)) increases during migraine, but the cause of the increase is not known. OBJECTIVE: Analyze biochemical pathways that influence [Na(+)](csf) to identify mechanisms that are consistent with migraine. METHOD: We reviewed sodium physiology and biochemistry publications for links to migraine and pain. RESULTS: Increased capillary endothelial cell (CEC) Na(+), K(+), -ATPase transporter (NKAT) activity is probably the primary cause of increased [Na(+)](csf). Physiological fluctuations of all NKAT regulators in blood, many known to be involved in migraine, are monitored by receptors on the luminal wall of brain CECs; signals are then transduced to their abluminal NKATs that alter brain extracellular sodium ([Na(+)](e)) and potassium ([K(+)](e)). CONCLUSIONS: We propose a theoretical mechanism for aura and migraine when NKAT activity shifts outside normal limits: (1) CEC NKAT activity below a lower limit increases [K(+)](e), facilitates cortical spreading depression, and causes aura; (2) CEC NKAT activity above an upper limit elevates [Na(+)](e), increases neuronal excitability, and causes migraine; (3) migraine-without-aura may arise from CEC NKAT over-activity without requiring a prior decrease in activity and its consequent spreading depression; (4) migraine triggers disturb, and treatments improve, CEC NKAT homeostasis; (5) CEC NKAT-induced regulation of neural and vasomotor excitability coordinates vascular and neuronal activities, and includes occasional pathology from CEC NKAT-induced apoptosis or cerebral infarction.