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The kinetic responses of leukocyte subsets to exercise and their recovery may serve as indicators of immunological resilience. These time-dependent responses were investigated in healthy young men using a bicycle ergometer test. Fifteen recreationally active male cyclists (20–35 years, VO2max 56.9 ± 3.9 mL kg−1 min−1) performed four exercise protocols with a 1 h duration in a cross-over design: at 70% of the maximal workload (Wmax) in a hydrated and a mildly dehydrated state, at 50% of the Wmax, and intermittently at 85/55% of the Wmax in blocks of 2 min. The numbers of lymphocytes, monocytes, neutrophils, eosinophils, basophils, thrombocytes, and NK cells (CD16 and CD56) were measured at different time points up to 24 h post-exercise. The total leukocyte counts and those of most subsets increased from the start of the exercise, peaking after 30–60 min of exercising. The neutrophil numbers, however, peaked 3 h post-exercise. The CD16brightCD56dim NK cells showed a 1.5-fold increase compared to the CD16brightCD56bright NK cells. Other than for MCP-1, no significant differences were found in the serum cytokine levels. Our results show that exercise intensity is reflected in different time-dependent changes in leukocyte subsets, which supports the concept that the exchange of immune cells between peripheral blood and tissues contributes to enhanced immune surveillance during strenuous exercise.

The utility of 3D-small intestinal organoid (enteroid) models for evaluating effects of e.g. food (related) compounds is limited due to the apical epithelium facing the interior. To overcome this limitation, we developed a novel 3D-apical-out enteroid model for mice, which allows apical exposure. Using this model, we evaluated the effects on the enteroids’ intestinal epithelium (including cytotoxicity, cell viability, and biotransformation) after exposure to glabridin, a prenylated secondary metabolite with antimicrobial properties from licorice roots (Glycyrrhiza glabra). Apical-out enteroids were five times less sensitive to glabridin exposure compared to conventional apical-in enteroids, with obtained cytotoxicities of 1.5 mM and 0.31 mM, respectively. Apical-out enteroids showed a luminal/apical layer of fucose rich mucus, which may contribute to the protection against potential cytotoxicity of glabridin. Furthermore, in apical-in enteroids IC50 values for cytotoxicity were determined for licochalcone A, glycycoumarin, and glabridin, the species-specific prenylated phenolics from the commonly used G. inflata, G. uralensis, and G. glabra, respectively. Both enteroid models differed in their functional phase II biotransformation capacity, where glabridin was transformed to glucuronide- and sulfate-conjugates. Lastly, our results indicate that the prenylated phenolics do not show cytotoxicity in mouse enteroids at previously reported minimum inhibitory concentrations (MICs) against a diverse set of Gram positive bacteria. Altogether, we show that apical-out enteroids provide a better mimic of the gastrointestinal tract compared to conventional enteroids and are consequently a superior model to study effects of food (related) compounds. This work revealed that prenylated phenolics with promising antibacterial activity show no harmful effects in the GI-tract at their MICs and therefore may offer a new perspective to control unwanted microbial growth.

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.

AIM: To investigate the effects of exercise on salivary concentrations of inflammatory markers by analyzing a panel of 25 inflammatory markers in subjects who had participated in bicycle ergometer tests varying in workload and hydration status.METHODS: Fifteen healthy young men (20-35 years) had performed 4 different exercise protocols of 1 hour duration in a randomly assigned cross-over design, preceded by a rest protocol. Individual workloads depended on participant's pre-assessed individual maximum workload (Wmax): rest (protocol 1), 70% Wmax in hydrated (protocol 2) and dehydrated (protocol 3) state, 50% Wmax (protocol 4) and intermittent 85%/55% Wmax in 2 min blocks (protocol 5). Saliva samples were collected before (T0) and immediately after exercise (T1), and at several time points after exercise (2 hours (T3), 3 hours (T4), 6 hours (T5) and 24 hours (T6)). Secretory Leukocyte Protease Inhibitor (SLPI), Matrix Metallopeptidase-9 (MMP-9) and lactoferrin was analyzed using a commercial ELISA kit, a panel of 22 cytokines and chemokines were analyzed using a commercial multiplex immunoassay. Data was analyzed using a multilevel mixed linear model, with multiple test correction.RESULTS: Among a panel of 25 inflammatory markers, SLPI concentrations were significantly elevated immediately after exercise in all protocols compared to rest and higher concentrations reflected the intensity of exercise and hydration status. MMP-9 showed a significant increase in the 70% Wmax dehydrated, 50% Wmax and intermittent protocols.CONCLUSIONS: Salivary concentrations of SLPI and MMP-9 seem associated with exercise intensity and hydration status and may offer non-invasive biomarkers to study (local) inflammatory responses to different exercise intensities in human studies.

Glucagon-like peptide 1 (GLP-1) is a multifaceted intestinal hormone with diverse physiological functions throughout the body. Previously, we demonstrated that the steviol glycoside rebaudioside A (rebA) from Stevia rebaudiana stimulates the release of GLP-1 from mouse intestinal organoids and pig intestinal segments. To further unravel the underlying mechanisms, we examined the involvement of sweet- and bitter taste receptors and their associated signal transduction pathways. Experiments with mouse and human intestinal enteroendocrine cell lines (STC-1 and HuTu-80, respectively) confirmed that rebA stimulates GLP-1 release in a concentration-dependent manner. Experiments with selective inhibitors of sweet signalling in both the murine as well as the human enteroendocrine cells showed that the GLP-1-induced release by rebA occurs independently of the sweet taste receptor. Functional screening of 34 murine bitter taste receptors (Tas2rs) revealed an activation response with Tas2r108, Tas2r123 and Tas2r134. Moreover, we found evidence in human HuTu-80 cells, that TAS2R4 and TRPM5 are involved in rebA-induced GLP-1 secretion, suggesting a role for bitter taste signaling in gut hormone release. Interestingly, the rebA-dependent GLP-1 release may be modulated by GABA and 6-methoxyflavanone present in the diet. Together, our findings warrant further characterization of the specific metabolic effects of rebA among the non-caloric sweeteners.

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.

Background:Vitamin D deficiency is associated with all-cause dementia and Alzheimer’s disease (AD). At the same time, this knowledge is limited specifically for vascular dementia (VaD), while data regarding other subtypes of dementia are even more limited. Objective:To investigate the association of 25-hydroxy vitamin D (25(OH)D) status with dementia subtypes in an outpatient geriatric population. Methods:In a cross-sectional design, we analyzed data from 1,758 patients of an outpatient memory clinic in The Netherlands. Cognitive disorders were diagnosed by a multidisciplinary team according to international clinical standards. At each first-visit 25(OH)D levels were measured. Data were analyzed using ANCOVA in four models with age, gender, BMI, education, alcohol, smoking, season, polypharmacy, calcium, eGFR, and glucose as co-variates. 25(OH)D was treated as a continuous square rooted (sqr) variable. Results:In the fully adjusted model, reduced 25(OH)D serum levels (sqr) were found in AD (estimated mean 7.77±0.11 CI95% 7.55-7.99): and in VaD (estimated mean 7.60±0.16 CI95% 7.28-7.92) patients compared to no-dementia (ND) patients (estimated mean 8.27±0.09 CI95% 8.10-8.45) (ND-AD: p = 0.006, CI95% 0.08-0.92.; ND-VaD p = 0.004 CI95% 0.13-1.22). We did not find differences in 25(OH)D levels of mild cognitive impairment (MCI) or other dementia patients compared to ND patients, nor differences in comparing dementia subtypes. Conclusion:We observed significantly lower 25(OH)D serum levels in both AD and VaD patients compared to no-dementia patients, but no significant differences between MCI and Lewy body and mixed dementia subtypes in this cross-sectional study of a geriatric outpatient clinic population.