Endocannabinoid levels in plasma and neurotransmitters in the brain: a preliminary report on patients with a psychotic disorder and healthy individuals.

BACKGROUND: Interactions between the endocannabinoid system (ECS) and neurotransmitter systems might mediate the risk of developing a schizophrenia spectrum disorder (SSD). Consequently, we investigated in patients with SSD and healthy controls (HC) the relations between (1) plasma concentrations of two prototypical endocannabinoids (N-arachidonoylethanolamine [anandamide] and 2-arachidonoylglycerol [2-AG]) and (2) striatal dopamine synthesis capacity (DSC), and glutamate and y-aminobutyric acid (GABA) levels in the anterior cingulate cortex (ACC). As anandamide and 2-AG might reduce the activity of these neurotransmitters, we hypothesized negative correlations between their plasma levels and the abovementioned neurotransmitters in both groups. METHODS: Blood samples were obtained from 18 patients and 16 HC to measure anandamide and 2-AG plasma concentrations. For all subjects, we acquired proton magnetic resonance spectroscopy scans to assess Glx (i.e. glutamate plus glutamine) and GABA + (i.e. GABA plus macromolecules) concentrations in the ACC. Ten patients and 14 HC also underwent [18F]F-DOPA positron emission tomography for assessment of striatal DSC. Multiple linear regression analyses were used to investigate the relations between the outcome measures. RESULTS: A negative association between 2-AG plasma concentration and ACC Glx concentration was found in patients (p = 0.008). We found no evidence of other significant relationships between 2-AG or anandamide plasma concentrations and dopaminergic, glutamatergic, or GABAergic measures in either group. CONCLUSIONS: Our preliminary results suggest an association between peripheral 2-AG and ACC Glx levels in patients.

Changes in nutrient composition and diet quality in the first 6 months following bariatric surgery: An observational cohort study.

BACKGROUND: Bariatric surgery (BS) may result in inadequate nutrient intake and poor diet quality, which can lead to nutritional complications. The present study aimed to evaluate changes in macro- and micronutrient composition and diet quality in the first 6 months following BS. METHODS: One hundred seven participants undergoing BS (Roux-en-Y gastric bypass: n = 87, sleeve gastrectomy: n = 20) completed 3-day food records before and 6 months after surgery. Changes in energy, macronutrient (carbohydrates, protein, fat, dietary fibre) and micronutrient intake (folate, vitamin B12, vitamin D, calcium, iron) were evaluated. Diet quality was assessed by adherence to the Dutch food-based dietary guidelines. RESULTS: After BS, we observed a significant decrease in intake of energy and all macro- and micronutrients (p < 0.01 for all), except for calcium (-39.0 ± 404.6 mg; p = 0.32). Overall, nutrient composition slightly changed with an increase in the relative intake of protein (+1.1 ± 4.3 energy percentage [en%]; p = 0.01) and mono- and disaccharides (+4.2 ± 6.4 en%; p < 0.001) post-surgery. Consumption (median [Q1, Q3]) of vegetables (-50 [-120, 6] g day-1 ), wholegrain products (-38 [-81, -8] g day-1 ), liquid fats (-5 [-13, 2] g day-1 ), red meat (-3 [-30, 4] g day-1 ), processed meat (-32 [-55, 13] g day-1 ), sodium (-0.7 [-1.1, -0.2] g day-1 ) and unhealthy food choices (-2.4 [-5.0, 0.6] serves week-1 ) significantly decreased after BS (p < 0.01 for all). CONCLUSIONS: Our results demonstrate both favourable and unfavourable changes in macro- and micronutrient composition and diet quality in the first 6 months following BS. Insight into these changes can improve dietary counselling in this population. Future research into underlying causes, consequences and long-term changes in dietary intake is needed.

Association between Low Vitamin D Status, Serotonin, and Clinico-Biobehavioral Parameters in Alzheimer's Disease.

INTRODUCTION: Studies suggest a role of vitamin D in the progression and symptomatology of Alzheimer's disease (AD), with few in vitro studies pointing to effects on serotonergic and amyloidogenic turnover. However, limited data exist in AD patients on the potential association with cognition and behavioral and psychological signs and symptoms of dementia (BPSD). In this retrospective cross-sectional study, we, therefore, explored potential correlations of serum 25-hydroxyvitamin D3 (25(OH)D3) concentrations, indicative of vitamin D status, with serum serotonin (5-hydroxytryptamine, 5-HT) levels, cognitive/BPSD scorings, and cerebrospinal fluid (CSF) biomarker levels. METHODS: Frozen serum samples of 25 well-characterized AD subjects as part of a previous BPSD cohort were analyzed, of which 15 had a neuropathologically confirmed diagnosis. Serum 25(OH)D3 levels were analyzed by means of LC-MS/MS, whereas 5-HT concentrations were quantified by competitive ELISA. RESULTS: Among AD patients, vitamin D deficiency was highly prevalent, defined as levels below 50 nmol/L. Regression analyses, adjusted for age, gender, and psychotropic medications, revealed that serum 25(OH)D3 and 5-HT levels were positively associated (p = 0.012). Furthermore, serum 25(OH)D3 concentrations correlated inversely with CSF amyloid-beta (Aß1-42) levels (p = 0.006), and serum 5-HT levels correlated positively with aggressiveness (p = 0.001), frontal behavior (p = 0.001), depression (p = 0.004), and partly with cognitive performance (p < 0.005). Lastly, AD patients on cholinesterase inhibitors had higher serum 25(OH)D3 (p = 0.030) and lower serum 5-HT (p = 0.012) levels. CONCLUSIONS: The molecular associations between low vitamin D status, serum 5-HT, and CSF Aß1-42 levels are highly remarkable, warranting further mechanistic and intervention studies to disclose potential involvement in the clinico-biobehavioral pathophysiology of AD.

Docosahexaenoyl serotonin emerges as most potent inhibitor of IL-17 and CCL-20 released by blood mononuclear cells from a series of N-acyl serotonins identified in human intestinal tissue.

Fatty acid amides (FAAs), conjugates of fatty acids with ethanolamine, mono-amine neurotransmitters or amino acids are a class of molecules that display diverse functional roles in different cells and tissues. Recently we reported that one of the serotonin-fatty acid conjugates, docosahexaenoyl serotonin (DHA-5-HT), previously found in gut tissue of mouse and pig, attenuates the IL-23-IL-17 signaling axis in LPS-stimulated mice macrophages. However, its presence and effects in humans remained to be elucidated. Here, we report for the first time its identification in human intestinal (colon) tissue, along with a series of related N-acyl serotonins. Furthermore, we tested these fatty acid conjugates for their ability to inhibit the release of IL-17 and CCL-20 by stimulated human peripheral blood mononuclear cells (PBMCs). Serotonin conjugates with palmitic acid (PA-5-HT), stearic acid (SA-5-HT) and oleic acid (OA-5-HT) were detected in higher levels than arachidonoyl serotonin (AA-5-HT) and DHA-5-HT, while eicosapentaenoyl serotonin (EPA-5-HT) could not be quantified. Among these, DHA-5-HT was the most potent in inhibiting IL-17 and CCL-20, typical Th17 pro-inflammatory mediators, by Concanavalin A (ConA)-stimulated human PBMCs. These results underline the idea that DHA-5-HT is a gut-specific endogenously produced mediator with the capacity to modulate the IL-17/Th17 signaling response. Our findings may be of relevance in relation to intestinal inflammatory diseases like Crohn's disease and Ulcerative colitis.

Decrease in Ionized and Total Magnesium Blood Concentrations in Endurance Athletes Following an Exercise Bout Restores within Hours-Potential Consequences for Monitoring and Supplementation.

Magnesium is essential for optimal sport performance, generating an interest to monitor its status in athletes. However, before measuring magnesium status in blood could become routine, more insight into its diurnal fluctuations and effects of exercise itself is necessary. Therefore, we measured the effect of an acute bout of exercise on ionized (iMg) and total plasma magnesium (tMg) in blood obtained from 18 healthy well-trained endurance athletes (age, 31.1 ± 8.1 yr.; VO2max, 50.9 ± 7.5 ml/kg/min) at multiple time points, and compared this with a resting situation. At both days, 7 blood samples were taken at set time points (8:30 fasted, 11:00, 12:30, 13:30, 15:00, 16:00, 18:30). The control day was included to correct for a putative diurnal fluctuation of magnesium. During the exercise day, athletes performed a 90 min bicycle ergometer test (70% VO2max) between 11:00 and 12:30. Whole blood samples were analyzed for iMg and plasma for tMg concentrations. Both concentrations decreased significantly after exercise (0.52 ± 0.04-0.45 ± 0.03 mmol/L and 0.81 ± 0.07-0.73 ± 0.06 mmol/L, respectively, p < .001) while no significant decline was observed during that time-interval on control days. Both, iMg and tMg, returned to baseline, on average, 2.5 hr after exercise. These findings suggest that timing of blood sampling to analyze Mg status is important. Additional research is needed to establish the recovery time after different types of exercise to come to a general advice regarding the timing of magnesium status assessment in practice.

Nutrient composition of different energy-restricted diets determines plasma endocannabinoid profiles and adipose tissue DAGL-α expression; a 12-week randomized controlled trial in subjects with abdominal obesity.

The endocannabinoid system (ECS) is dysregulated during obesity and metabolic disorders. Weight loss favours the re-establishment of ECS homeostatic conditions, but also the fatty acid composition of the diet can modulate endocannabinoid profiles. However, the combined impact of nutrient quality and energy restriction on the ECS remains unclear. In this 12 weeks randomized controlled trial, men and women (40-70 years) with obesity (BMI: 31.3 ± 3.5 kg/ m2) followed either a low nutrient quality 25% energy-restricted (ER) diet (n=39) high in saturated fats and fructose, or a high nutrient quality ER diet (n=34) amongst others enriched in n-3 polyunsaturated fatty acids (PUFAs) or kept their habitual diet (controls). Profiles of plasma- and adipose N-acylethanolamines and mono-acyl glycerol esters were quantified using LC-MS/MS. Gene expression of ECS-related enzymes and receptors was determined in adipose tissue. Measurements were performed under fasting conditions before and after 12 weeks. Our results showed that plasma level of the DHA-derived compound docosahexaenoylethanolamide (DHEA) was decreased in the low nutrient quality ER diet (P<0.001) compared with the high nutrient quality ER diet, whereas anandamide (AEA) and arachidonoylglycerol (2-AG) levels were unaltered. However, adipose tissue gene expression of the 2-AG synthesizing enzyme diacylglycerol lipase alpha (DAGL-α) was increased following the low nutrient quality ER diet (P<.009) and differed upon intervention with both other diets. Concluding, nutrient quality of the diet affects N-acylethanolamine profiles and gene expression of ECS-related enzymes and receptors even under conditions of high energy restriction in abdominally obese humans. ClinicalTrials.gov NCT02194504.

Liquid chromatography-tandem mass spectrometry analysis of free and esterified fatty acid N-acyl ethanolamines in plasma and blood cells.

The origin of N-acyl ethanolamides (NAEs) in plasma is not well understood, and it is possible that NAEs are present in plasma in esterified form. To test this hypothesis, a new and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of arachidonoyl ethanolamide, 2-arachidonoyl glycerol, docosahexaenoyl ethanolamide, dihomo-γ-linolenoyl ethanolamide, oleoyl ethanolamide, palmitoyl ethanolamide, and stearoyl ethanolamide in 100 µl of human plasma using a simple acetonitrile extraction step. Using this method, we determined (i) free and esterified NAE levels in human plasma, (ii) free and esterified NAE levels in plasma of mice fed with diets with different amounts of n-3 fatty acids, and (iii) esterified NAE levels in blood cells. Murine and human plasma extracts contained 20- to 60-fold higher levels of esterified NAEs than free NAEs. Moreover, the effect of dietary n-3 fatty acids on murine free plasma NAE profiles was similar for esterified NAEs. Finally, esterified NAEs were also present in murine blood cells, and their pattern followed the same diet effect as observed for free and esterified NAEs in plasma. Together, these data point to the presence of previously ignored pools of esterified NAEs in plasma and blood cells that correlated well with free NAE levels in plasma.

Analysis of Omega-3 Fatty Acid-Derived N-Acylethanolamines in Biological Matrices.

The adequate quantification of endocannabinoids and related N-acylethanolamines can be complex due to their low endogenous levels, structural diversity, and metabolism. Therefore, advanced analytical approaches, involving LC-MS, are required to quantify these molecules in plasma, tissues, and other matrices. It has been shown that endocannabinoid congeners synthesized from n-3 poly-unsaturated fatty acids (n-3 PUFAs), such as docosahexaenoylethanolamide (DHEA) and eicosapentaenoylethanolamide (EPEA), have interesting immunomodulatory and tumor-inhibiting properties. Recent work has shown that DHEA and EPEA can be further enzymatically metabolized by cyclo-oxygenase 2 (COX-2), forming oxygenated metabolites. Here, an LC-MS-based method for the quantification of the n-3 PUFA-derived endocannabinoid congeners DHEA and EPEA is described, which is also suited to measure a wider spectrum of endocannabinoids. The chapter contains a step-by-step protocol for the analysis of (n-3) endocannabinoids in plasma, including sample collection and solid phase extraction, LC-MS analysis, and data processing. In addition, protocol modifications are provided to allow quantification of n-3 PUFA-derived endocannabinoids and their COX-2 metabolites in tissues and cell culture media. Finally, conditions that alter endocannabinoid concentrations are briefly discussed.

Development and validation of a UPLC-MS/MS method for the quantification of sugars and non-nutritive sweeteners in human urine.

High-intensity sweeteners ('sweeteners'), such as sucralose, saccharine, acesulfame, cyclamate and steviol, are replacing sugars in many food products, but biomarker-based data on their population-wide exposure, as well as analytical methods that can quantify urinary concentrations of sugars and sweeteners simultaneously, are lacking. Here, we developed and validated an ultra-pressure liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) method to quantify glucose, sucrose, fructose, sucralose, saccharine, acesulfame, cyclamate and steviol glucuronide in human urine. Urine samples were prepared by a simple dilution step containing the internal standards in water and methanol. Separation was achieved on a Shodex Asahipak NH2P-40 hydrophilic interaction liquid chromatography (HILIC) column using gradient elution. The analytes were detected using electrospray ionization in negative ion mode, and selective reaction monitoring was optimized using the [M-H]- ions. Calibration curves ranged between 34 and 19,230 ng/mL for glucose and fructose, and 1.8 to 1,026 ng/mL for sucrose and the sweeteners. The method has acceptable accuracy and precision, which depends on the application of appropriate internal standards. Storage of urine samples in lithium monophosphate gives the best overall analytical performance, and storage at room temperature without any preservatives should be avoided since this leads to reduced glucose and fructose concentrations. With the exception of fructose, all analytes were stable throughout 3 freeze-thaw cycles. The validated method was applied to human urine samples, demonstrating quantifiable concentrations of the analytes which were in the expected range. It is concluded that the method has acceptable performance to quantitatively determine dietary sugars and sweeteners in human urine.

Efficacy and utility of a tool for both measurement of vitamin B6, B12, D, folate and iron status and assessment of diet quality in athletes.

NutriProfiel® is a tool to measure micronutrient status and to assess diet quality. It consists of measurement of micronutrient status in blood and a short food frequency questionnaire (FFQ) ('Eetscore-FFQ'). Based on the results, individuals receive a dietary advice. In this study, we evaluated the application of NutriProfiel in athletes ('NutriProfiel-Sport') by assessing the coverage of nutrient intake of the Eetscore-FFQ (part 1) and by evaluating athlete's dietary behaviour after using NutriProfiel-Sport and their satisfaction with this tool (part 2). For part 1, data of 419 athletes were used. We evaluated the coverage of nutrient intake of the Eetscore-FFQ using first and second MOMents (MOM1 and MOM2) sum scores of food items in the questionnaire. Forty-eight athletes were involved in part 2. They gave blood samples for micronutrient status measurement and were asked to complete the Eetscore-FFQ at baseline and after 3 months, as well as a questionnaire on their satisfaction with NutriProfiel-Sport. Results showed that for most nutrients, MOM1 and MOM2 scores were above 80 %, meaning that nutrient intake was sufficiently covered by the Eetscore-FFQ. No difference in diet quality was observed between baseline and after 3 months. Nevertheless, a majority of athletes reported the NutriProfiel-Sport results and advice as useful. On a scale from 0 to 10, NutriProfiel-Sport was graded with a mean (±sd) score of 7⋅6 (±0⋅8). In conclusion, NutriProfiel-Sport is a potential valuable and appreciated tool for athletes and the Eetscore-FFQ as part of this tool sufficiently covers nutrient intake in athletes.

Presence, formation and putative biological activities of N-acyl serotonins, a novel class of fatty-acid derived mediators, in the intestinal tract.

Following the discovery of the endocannabinoid arachidonoyl ethanolamide (anandamide) and other N-acyl-ethanolamines, several other compounds have been found in which amino acids or neurotransmitters rather than ethanolamide are linked to fatty acids. Studies have shown that the local availability of fatty acid precursors, which in turn is modulated by dietary intake of lipids, determines the pattern of conjugates formed. Less information is available whether the same might be true for the amines or neurotransmitters involved. We hypothesized that N-arachidonoyl-serotonin (AA-5-HT) and its analogs could be endogenously present in those tissues that have high contents of serotonin. We investigated the endogenous presence of N-acyl serotonins in different parts of the gastro-intestinal tract of pigs and mice. We discovered that AA-5-HT, oleoyl-serotonin, palmitoyl-serotonin, and stearoyl-serotonin were endogenously present, particularly in the jejunum and ileum. Their formation in vitro was stimulated by the addition of serotonin to intestinal tissue incubations. Furthermore, in a mouse study we showed that the pattern of formation is dependent on the relative amount of fatty acids in the diet. The formation of docosahexaenoyl-serotonin and eicosapentaenoyl-serotonin was elevated in mice fed with a diet containing fish oil. Preliminary data showed that several of the serotonin conjugates are able to inhibit glucagon-like peptide-1 secretion and FAAH activity in vitro. Taken together, our data suggest that N-acyl serotonins are a novel class of lipid mediators present in the gut with highly promising biological properties.

The influence of a tomato food matrix on the bioavailability and plasma kinetics of oral gamma-aminobutyric acid (GABA) and its precursor glutamate in healthy men.

Gamma-aminobutyric acid (GABA) and its precursor glutamate play signaling roles in a range of tissues. Both function as neurotransmitters in the central nervous system, but they also modulate pancreatic and immune functioning, for example. Besides endogenous production, both compounds are found in food products, reaching relatively high levels in tomatoes. Recent studies in rodents suggest beneficial effects of oral GABA on glucose homeostasis and blood pressure. However, the bioavailability from food remains unknown. We studied the bioavailability of GABA and glutamate from tomatoes relative to a solution in water. After a fasting blood sample was taken, eleven healthy men randomly received 1 liter of 4 different drinks in a cross-over design with a one-week interval. The drinks were a solution of 888 mg L-1 GABA, a solution of 3673 mg L-1 glutamate, pureed fresh tomatoes and plain water as the control. Following intake, 18 blood samples were taken at intervals for 24 hours. Plasma GABA and glutamate concentrations were determined by ultra-pressure liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). Fasting plasma GABA and glutamate concentrations were found to be 16.71 (SD 2.18) ng mL-1 and 4626 (SD 1666) ng mL-1, respectively. Fasting GABA levels were constant (5.8 CV%) between individuals, while fasting glutamate levels varied considerably (23.5 CV%). GABA from pureed tomatoes showed similar bioavailability to that of a solution in water. For glutamate, the absorption from pureed tomatoes occurred more slowly as seen from a longer tmax (0.98 ± 0.14 h vs. 0.41 ± 0.04 h, P = 0.003) and lower Cmax (7815 ± 627 ng mL-1vs. 16 420 ± 2778 ng mL-1, P = 0.006). These data suggest that GABA is bioavailable from tomatoes, and that food products containing GABA could potentially induce health effects similar to those claimed for GABA supplements. The results merit further studies on the bioavailability of GABA from other food products and the health effects of GABA-rich diets. The clinical trial registry number is NCT04086108 (https://clinicaltrials.gov/ct2/show/NCT04303468).

PUFA-Derived N-Acylethanolamide Probes Identify Peroxiredoxins and Small GTPases as Molecular Targets in LPS-Stimulated RAW264.7 Macrophages.

We studied the mechanistic and biological origins of anti-inflammatory poly-unsaturated fatty acid-derived N-acylethanolamines using synthetic bifunctional chemical probes of docosahexaenoyl ethanolamide (DHEA) and arachidonoyl ethanolamide (AEA) in RAW264.7 macrophages stimulated with 1.0 µg mL-1 lipopolysaccharide. Using a photoreactive diazirine, probes were covalently attached to their target proteins, which were further studied by introducing a fluorescent probe or biotin-based affinity purification. Fluorescence confocal microscopy showed DHEA and AEA probes localized in cytosol, specifically in structures that point toward the endoplasmic reticulum and in membrane vesicles. Affinity purification followed by proteomic analysis revealed peroxiredoxin-1 (Prdx1) as the most significant binding interactor of both DHEA and AEA probes. In addition, Prdx4, endosomal related proteins, small GTPase signaling proteins, and prostaglandin synthase 2 (Ptgs2, also known as cyclooxygenase 2 or COX-2) were identified. Lastly, confocal fluorescence microscopy revealed the colocalization of Ptgs2 and Rac1 with DHEA and AEA probes. These data identified new molecular targets suggesting that DHEA and AEA may be involved in reactive oxidation species regulation, cell migration, cytoskeletal remodeling, and endosomal trafficking and support endocytosis as an uptake mechanism.

Docosahexaenoic acid and eicosapentaenoic acid are converted by 3T3-L1 adipocytes to N-acyl ethanolamines with anti-inflammatory properties.

n-3 PUFAs have beneficial health effects which are believed to be partly related to their anti-inflammatory properties, however the exact mechanisms behind this are unknown. One possible explanation could be via their conversion to N-acyl ethanolamines (NAEs), which are known to possess anti-inflammatory properties. Using fatty acid precursors we showed that 3T3-L1 adipocytes are indeed able to convert docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) to their NAE derivatives docosahexaenoyl ethanolamine (DHEA) and eicosapentaenoyl ethanolamine (EPEA), respectively. This synthesis took place on top of an apparent background formation of these NAEs in standard culture medium. In addition we were able to demonstrate the presence of DHEA, but not of EPEA, in human plasma. DHEA and EPEA were found to decrease LPS induced adipocyte IL-6 and MCP-1 levels. Results of combined incubations with PPAR-gamma and CB2 antagonists suggest a role of these receptors in mediating the reduction of IL-6 by DHEA. Our results are in line with the hypothesis that in addition to other pathways, formation of N-acyl ethanolamines may contribute to the biological activity of n-3 PUFAs. Different targets, including the endocannabinoid system, may be involved in the immune-modulating activity of these "fish-oil-derived NAEs."

Development and validation of a UPLC-MS/MS method for the simultaneous determination of gamma-aminobutyric acid and glutamic acid in human plasma.

Gamma-aminobutyric acid (GABA) and its precursor glutamic acid are important neurotransmitters. Both are also present in peripheral tissues and the circulation, where abnormal plasma concentrations have been linked to specific mental disorders. In addition to endogenous synthesis, GABA and glutamic acid can be obtained from dietary sources. An increasing number of studies suggest beneficial cardio-metabolic effects of GABA intake, and therefore GABA is being marketed as a food supplement. The need for further research into their health effects merits accurate and sensitive methods to analyze GABA and glutamic acid in plasma. To this end, an ultra-pressure liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the quantification of GABA and glutamic acid in human plasma. Samples were prepared by a protein precipitation step and subsequent solid phase extraction using acetonitrile. Chromatographic separation was achieved on an Acquity UPLC HSS reversed phase C18 column using gradient elution. Analytes were detected using electrospray ionization and selective reaction monitoring. Standard curve concentrations for GABA ranged from 3.4 to 2500 ng/mL and for glutamic acid from 30.9 ng/mL to 22,500 ng/mL. Within- and between-day accuracy and precision were <10% in quality control samples at low, medium and high concentrations for both GABA and glutamic acid. GABA and glutamic acid were found to be stable in plasma after freeze-thaw cycles and up to 12 months of storage. The validated method was applied to human plasma from 17 volunteers. The observed concentrations ranged between 11.5 and 20.0 ng/ml and 2269 and 7625 ng/ml for respectively GABA and glutamic acid. The reported method is well suited for the measurement of plasma GABA and glutamic acid in pre-clinical or clinical studies.

Pitfalls in interpreting red blood cell parameters in elite high-altitude and sea-level athletes: A unique case series.

Standard routine hematological measurements are commonly used to investigate differences in blood parameters between high-altitude athletes (HAA) and sea-level athletes (SLA), and to monitor the effect of high-altitude training. In this way, red blood cell (RBC) parameters are usually expressed as relative parameters (concentration) rather than absolute parameters (total amount). In this unique case series of elite HAA and SLA, we describe how different ways of parameter expression can affect the interpretation of blood tests. In a group of 42 elite athletes, relative and absolute RBC parameters were compared between HAA and SLA. Absolute parameters were calculated by multiplying relative values with formula-based estimated blood volume (BV-e). Additionally, in two individual athletes, one HAA and one SLA, absolute parameters were also calculated with blood volume (BV) obtained by measurement with a dilution method (BV-m). In men, HAA had a significantly higher hemoglobin (Hb) concentration (+7.8%; p = 0.001) and total Hb mass per kg body weight (BW) (+12.0%; p = 0.002). When not corrected for BW, HAA had a lower, non-significant, total Hb mass (-7.8%; p = 0.055). In women, no significant differences between HLA and SLA were observed. The two individual athletes showed that, based on BV-m, in the HAA, total Hb mass and total Hb mass per kg BW were respectively 14.1% and 31.0% higher than in the SLA, whereas based on BV-e, in the HAA, total Hb mass was 20.8% lower and total Hb mass per kg BW was only 2.4% higher. Similar inconsistencies were observed for total RBC count. Thus, different ways of parameter expression, and different methods of BV assessment for the calculation of absolute parameter values, influence the interpretation of blood tests in athletes, which may lead to misinterpretation and incorrect conclusions.

Immunomodulating effects of 13- and 16-hydroxylated docosahexaenoyl ethanolamide in LPS stimulated RAW264.7 macrophages.

Docosahexaenoyl ethanolamide (DHEA), the ethanolamine conjugate of the n-3 long chain polyunsaturated fatty acid docosahexaenoic acid, is endogenously present in the human circulation and in tissues. Its immunomodulating properties have been (partly) attributed to an interaction with the cyclooxygenase-2 (COX-2) enzyme. Recently, we discovered that COX-2 converts DHEA into two oxygenated metabolites, 13- and 16-hydroxylated-DHEA (13- and 16-HDHEA, respectively). It remained unclear whether these oxygenated metabolites also display immunomodulating properties like their parent DHEA. In the current study we investigated the immunomodulating properties of 13- and 16-HDHEA in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. The compounds reduced production of tumor necrosis factor alpha (TNFα), interleukin (IL)-1ß and IL-1Ra, but did not affect nitric oxide (NO) and IL-6 release. Transcriptome analysis showed that the compounds inhibited the LPS-mediated induction of pro-inflammatory genes (InhbA, Ifit1) and suggested potential inhibition of regulators such as toll-like receptor 4 (TLR4), MyD88, and interferon regulatory factor 3 (IRF3), whereas anti-inflammatory genes (SerpinB2) and potential regulators IL-10, sirtuin 1 (Sirt-1), fluticasone propionate were induced. Additionally, transcriptome analysis of 13-HDHEA suggests a potential anti-angiogenic role. In contrast to the known oxylipin-lowering effects of DHEA, liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) analyses revealed that 13- and 16-HDHEA did not affect oxylipin formation. Overall, the anti-inflammatory effects of 13-HDHEA and 16-HDHEA are less pronounced compared to their parent molecule DHEA. Therefore, we propose that COX-2 metabolism of DHEA acts as a regulatory mechanism to limit the anti-inflammatory properties of DHEA.

Levels of Inflammation Markers Are Associated with the Risk of Recurrence and All-Cause Mortality in Patients with Colorectal Cancer.

BACKGROUND: We investigated whether preoperative and postoperative levels of inflammation markers, which have mechanistically been linked to colorectal cancer progression, were associated with recurrence and all-cause mortality in patients with colorectal cancer. METHODS: Data of two prospective cohort studies were used. For the current analysis, patients with stage I to III colorectal cancer were considered. Data on inflammation [IL6, IL8, IL10, TNFα, high-sensitivity C-reactive protein (hsCRP), and a combined inflammatory z-score] were available for 747 patients before surgery and for 614 patients after surgery. The associations between inflammation marker levels and colorectal cancer recurrence and all-cause mortality were examined using multivariable Cox proportional hazard regression models, considering patient characteristics and clinical and lifestyle factors. RESULTS: Higher preoperative and postoperative hsCRP levels were associated with a higher risk of recurrence [HRper doubling (95% CI), 1.15 (1.02-1.30) and 1.34 (1.16-1.55)] and all-cause mortality [HRper doubling (95% CI) 1.13 (1.01-1.28) and 1.15 (0.98-1.35)]. A doubling in IL8 levels (preoperative levels HR = 1.23; 95% CI, 1.00-1.53 and postoperative levels HR = 1.61; 95% CI, 1.23-2.12) and a higher combined inflammatory z-score (preoperative HRper doubling = 1.39; 95% CI, 1.03-1.89 and postoperative HRper doubling = 1.56; 95% CI, 1.06-2.28) were associated with a higher risk of all-cause mortality, but not recurrence. No associations between IL6, IL10, and TNFα and recurrence or all-cause mortality were observed. CONCLUSIONS: Preoperative and postoperative levels of specific inflammation markers were associated with recurrence and/or all-cause mortality. IMPACT: The complex role of inflammation in cancer recurrence merits further elucidation by investigating local inflammation at the tumor site.

Inflammation Is a Mediating Factor in the Association between Lifestyle and Fatigue in Colorectal Cancer Patients.

Fatigue is very common among colorectal cancer (CRC) patients. We examined the association between adherence to the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) lifestyle recommendations and fatigue among stage I-III CRC patients, and whether inflammation mediated this association. Data from two prospective cohort studies were used. Adherence to the WCRF/AICR recommendations was expressed as a score ranging from 0-7, and assessed shortly after diagnosis. Six months post-diagnosis, fatigue was assessed with the European Organization for Research and Treatment of Cancer quality of life questionnaire C30 (EORTC QLQ-C30), and in a subpopulation, the plasma levels of inflammation markers (IL6, IL8, TNFα, and hsCRP) were assessed. Multiple linear regression analyses were performed to investigate the association between adherence to the WCRF/AICR recommendations and fatigue. To test mediation by inflammation, the PROCESS analytic tool developed by Hayes was used. A higher WCRF/AICR adherence score was associated with less fatigue six months after diagnosis (n = 1417, ß -2.22, 95%CI -3.65; -0.78). In the population of analysis for the mediation analyses (n = 551), the total association between lifestyle and fatigue was (ß -2.17, 95% CI -4.60; 0.25). A statistically significant indirect association via inflammation was observed (ß -0.97, 95% CI -1.92; -0.21), explaining 45% of the total association between lifestyle and fatigue (-0.97/-2.17 × 100). Thus, inflammation is probably one of the underlying mechanisms linking lifestyle to fatigue.

Natural Choline from Egg Yolk Phospholipids Is More Efficiently Absorbed Compared with Choline Bitartrate; Outcomes of A Randomized Trial in Healthy Adults.

Choline is a vitamin-like essential nutrient, important throughout one's lifespan. Therefore, choline salts are added to infant formula, supplements and functional foods. However, if choline is present in a natural form, e.g. bound to phospholipids, it may be more efficiently absorbed. The study's aim was to evaluate if choline uptake is improved after consumption of an egg yolk phospholipid drink, containing 3 g of phospholipid bound choline, compared to a control drink with 3 g of choline bitartrate. We performed a randomized, double blind, cross-over trial with 18 participants. Plasma choline, betaine and dimethylglycine concentrations were determined before and up to six hours after consumption of the drinks. The plasma choline response, as determined by the incremental area under the curve, was four times higher after consumption of the egg yolk phospholipid drink compared with the control drink (p < 0.01). Similar outcomes were also observed for choline's main metabolites, betaine (p < 0.01) and dimethylglycine (p = 0.01). Consumption of natural choline from egg yolk phospholipids improved choline absorption compared to consumption of chemically produced choline bitartrate. This information is of relevance for the food industry, instead of adding choline-salts, adding choline from egg yolk phospholipids can improve choline uptake and positively impact health.