Effects of Repeated High-Intensity Effort Training or Repeated Sprint Training on Repeated High-Intensity Effort Ability and In-Game Performance in Professional Rugby Union Players.

ABSTRACT: Glaise, P, Rogowski, I, and Martin, C. Effects of repeated high-intensity effort training or repeated sprint training on repeated high-intensity effort ability and in-game performance in professional rugby union players. J Strength Cond Res 38(5): 932-940, 2024-This study investigated the effects of repeated high-intensity efforts (RHIE) training compared with repeated sprint exercise (RSE) training on RHIE ability (RHIEa) and in-game performance in professional rugby union players. Thirty-nine, male, professional, rugby union players were randomly assigned to 3 training groups (RHIE training, RSE training, and control). Repeated high-intensity effort ability and high-intensity effort characteristics (including sprints, acceleration, and contact efforts) during official games were measured before and after a 10-week specific (RHIE, RSE, or control) training period. The results of this study showed that concerning RHIEa, both the RHIE and RSE training significantly increased the players' average sprint velocity ( p < 0.001, d = -0.39 and p < 0.001, d = -0.53 respectively), average sled push velocity (ASPV; p < 0.001, d = -0.81 and p = 0.017, d = -0.48 respectively), and RHIE score ( p < 0.001, d = -0.72 and p < 0.001, d = -0.60 respectively). Repeated high-intensity effort training trended in a smaller increase in average sprint velocity than RSE training, a larger increase in ASPV, and a similar increase in RHIE score. Concerning in-game high-intensity efforts, both the RHIE and RSE training produced significant improvements in the number of sprints ( p = 0.047, d = -0.28 and p < 0.001, d = -0.47 respectively), total distance ( p < 0.001, d = -0.50 and p = 0.002, d = -0.38 respectively), the number of accelerations ( p < 0.001, d = -0.37 and p = 0.003, d = -0.32 respectively), and contact rate ( p < 0.001, d = -0.97 and p = 0.020, d = -0.28 respectively). Conversely, the magnitude of the increase in contact rate was almost twice as high in RHIE compared with RSE training. To conclude, the findings of this study were that both RSE and RHIE training are effective methods for developing RHIEa and in-game high-intensity efforts in professional rugby union. In practical applications, as the gains in certain abilities and game performance data differed depending on the training method chosen, we suggest that coaches choose the most appropriate method according to the profile of the players, their position, and the style of play they want to develop.

Investigating the alterations of endocannabinoidome signaling in the human small intestine in the context of obesity and type 2 diabetes.

Background: Human studies have linked obesity-related diseases, such as type-2 diabetes (T2D), to the modulation of endocannabinoid signaling. Cannabinoid CB1 and CB2 receptor activation by the endocannabinoids (eCBs) 2-arachidonoylglycerol (2-AG) and N-arachidonoylethanolamine (AEA), both derived from arachidonic acid, play a role in homeostatic regulation. Other long chain fatty acid-derived endocannabinoid-like molecules have extended the metabolic role of this signaling system through other receptors. In this study, we aimed to assess in depth the interactions between the circulating and intestinal tone of this extended eCB system, or endocannabinoidome (eCBome), and their involvement in the pathogenesis of diabetes. Methods: Plasma and ileum samples were collected from subjects with obesity and harboring diverse degrees of insulin resistance or T2D, who underwent bariatric surgery. The levels of eCBome mediators and their congeners were then assessed by liquid chromatography coupled to tandem mass spectrometry, while gene expression was screened with qPCR arrays. Findings: Intestinal and circulating levels of eCBome mediators were higher in subjects with T2D. We found an inverse correlation between the intestinal and circulating levels of monoacylglycerols (MAGs). Additionally, we identified genes known to be implicated in both lipid metabolism and intestinal function that are altered by the context of obesity and glucose homeostasis. Interpretation: Although the impact of glucose metabolism on the eCBome remains poorly understood in subjects with advanced obesity state, our results suggest a strong causative link between altered glucose homeostasis and eCBome signaling in the intestine and the circulation.

Effect of knee joint angle on vastus medialis and vastus lateralis rigidity during isometric submaximal voluntary knee extensions.

The use of shear wave elastography during voluntary contraction has enabled the non-invasive assessment of load sharing strategies between agonist muscles. However, the change in joint angle and voluntary contraction intensity can modify contribution between muscles. The aim of this study was to investigate the effect of knee joint angle on the local mechanical properties of the vastus medialis (VM) and the vastus lateralis (VL) during isometric submaximal voluntary contractions from shear wave elastography mapping. The VM and VL Young's modulus at rest and during constant isometric submaximal voluntary contractions (i.e., 25%, 50% and 75% of maximal voluntary contraction [MVC]) were assessed for two knee angles (50° and 100° | knee fully extended = 0°) in twelve participants. No significant difference was found in the VM Young's modulus among all torque levels and knee angles (p > 0.05). VL Young's modulus was significantly higher at 25% MVC for a knee angle of 100° than at 75% MVC for the same knee angle and was greater at 25% MVC for a knee angle of 100° than for 50° (p < 0.05). In contrast to the VM, the contribution of the VL to the knee joint torque production during isometric voluntary contraction appears to depend on the muscle length and the relative knee extension torque level.

Comparative proximity biotinylation implicates the small GTPase RAB18 in sterol mobilization and biosynthesis.

Loss of functional RAB18 causes the autosomal recessive condition Warburg Micro syndrome. To better understand this disease, we used proximity biotinylation to generate an inventory of potential RAB18 effectors. A restricted set of 28 RAB18 interactions were dependent on the binary RAB3GAP1-RAB3GAP2 RAB18-guanine nucleotide exchange factor complex. Twelve of these 28 interactions are supported by prior reports, and we have directly validated novel interactions with SEC22A, TMCO4, and INPP5B. Consistent with a role for RAB18 in regulating membrane contact sites, interactors included groups of microtubule/membrane-remodeling proteins, membrane-tethering and docking proteins, and lipid-modifying/transporting proteins. Two of the putative interactors, EBP and OSBPL2/ORP2, have sterol substrates. EBP is a Δ8-Δ7 sterol isomerase, and ORP2 is a lipid transport protein. This prompted us to investigate a role for RAB18 in cholesterol biosynthesis. We found that the cholesterol precursor and EBP-product lathosterol accumulates in both RAB18-null HeLa cells and RAB3GAP1-null fibroblasts derived from an affected individual. Furthermore, de novo cholesterol biosynthesis is impaired in cells in which RAB18 is absent or dysregulated or in which ORP2 expression is disrupted. Our data demonstrate that guanine nucleotide exchange factor-dependent Rab interactions are highly amenable to interrogation by proximity biotinylation and may suggest that Micro syndrome is a cholesterol biosynthesis disorder.

Sex-related differences in endothelial function and blood viscosity in the elderly population.

Elderly represents a growing population and cardiovascular diseases (CVD) is one of the leading causes of mortality in this population. Sex differences are involved in CVD with middle-aged males being at higher risk than females. After menopause, females are no longer protected by hormones and the role of sex on cardiovascular parameters involved in CVD, such as endothelial function and blood viscosity, is still unclear. The purpose of this study was to investigate the effect of sex on endothelial function, blood viscosity and CVD in elderly. Clinical investigation and blood analyses were performed on 182 (93 females and 89 males) elderly participants (mean age: 75.83 ± 1.22). Health status of participants were classified. Sex differences in endothelial function, blood viscosity, high density lipoprotein (HDL), hematocrit, and red blood cell (RBC) aggregation were assessed. CVD prevalence was higher in males (27.0%) than in females (5.4%) (p < 0.001). Females had higher vasoreactivity (p = 0.014) and HDL (p < 0.001) level than males. Blood viscosity was higher in males than in females at any shear rate (p < 0.001). Hematocrit was greater in males than in females (p < 0.001) while RBC aggregation did not differ between the two populations. To conclude, females have less CVD than age-matched males that might be due to their greater vascular function and lower blood viscosity.

Opposition Skill Efficiency During Professional Rugby Union Official Games Is Related to Horizontal Force-Production Capacities in Sprinting.

PURPOSE: This study aimed to determine relationships between parameters of force-production capacity in sprinting and opposition skill efficiency in rugby union games according to position. METHODS: The sprint force-velocity profile of 33 professional rugby union players divided into 2 subgroups (forwards and backs) was measured on a 30-m sprint. Skill efficiencies (in percentage) of offensive duels, tackles, and rucks were assessed using objective criteria during 12 consecutive competitive games. Pearson correlation was used to determine the relationships between parameters of horizontal force-production capacity in sprinting (maximum propulsive power, theoretical maximum force [F0], theoretical maximum velocity, maximum ratio of horizontal force [RFmax], and rate of decrease of this ratio of forces with increasing velocity) and skill efficiencies. Two multiple linear regression models were used to observe whether skill efficiencies could depend on determinants of horizontal force application in low- or high-velocity conditions. A first model including F0 and theoretical maximum velocity was used as a macroscopic analysis, while a second model including RFmax and rate of decrease of this ratio of forces with increasing velocity was used as microscopic analysis to determine the most significant determinants of skill efficiency. RESULTS: All skill efficiencies were strongly correlated with maximum propulsive power in forwards and backs. In forwards, F0 and RFmax were the key predictors of dueling, rucking, and tackling efficiency. In backs, F0 was the main predictor of dueling and rucking efficiency, whereas RFmax was the key predictor of dueling and tackling efficiency. F0 and theoretical maximum velocity equivalently contributed to tackling performance. CONCLUSIONS: In rugby union forward and back players, skill efficiency is correlated with maximum propulsive power and may be more explained by horizontal force-production capacity and mechanical effectiveness at lower velocities than at higher velocities.

The influence of short sprint performance, acceleration, and deceleration mechanical properties on change of direction ability in soccer players-A cross-sectional study.

The study investigated the relationship between short sprint performance and mechanical parameters obtained during the acceleration and deceleration tasks with the change of direction (COD) performance in female and male soccer players. The acceleration and deceleration ability were compared in the "High/Fast" versus "Low/Slow" COD performance group based on a median split analysis in each sex group. One hundred three French soccer players were assessed for the sprinting Force-Velocity (F-V) profile (i.e., theoretical maximal force [F0], velocity [V0], power [Pmax]), 10 m performance, linear deceleration test (maximal braking force [HBFmax], braking power [BPmax], deceleration [Decmax]), and COD performance using 505-test. The 10 m performance was strongly associated with 505-test performance (ES = [0.64 to 0.71]), whereas the sprinting F-V profiles parameters were weakly to moderately correlated with 505- performance (ES = [-0.47 to -0.38]). The BPmax was also moderately associated with 505-test performance (ES: range = [-0.55 to -0.46]). In addition, the High/Fast female COD group presented higher F0, Pmax, HBFmax, and BPmax than the Low/Slow group, whereas the male groups presented very few mechanical differences. Multiple regression analysis shows that the COD performance of male players was determined by 10 m performance and maximum deceleration power. In contrast, no statistically significant model could be found to determine the change of direction performance in female players. In conclusion, the current finding indicated that the only variable strongly associated with COD performance was the linear 10 m sprint time. In the same way, the mechanical parameters obtained from acceleration and deceleration seemed to play a non-neglectable role in this population.

Impact of selenium on the intestinal microbiome-eCBome axis in the context of diet-related metabolic health in mice.

Dietary micronutrients act at the intestinal level, thereby influencing microbial communities, the host endocannabinoidome, and immune and anti-oxidative response. Selenium (Se) is a trace element with several health benefits. Indeed, Se plays an important role in the regulation of enzymes with antioxidative and anti-inflammatory activity as well as indicators of the level of oxidative stress, which, together with chronic low-grade inflammation, is associated to obesity. To understand how Se variations affect diet-related metabolic health, we fed female and male mice for 28 days with Se-depleted or Se-enriched diets combined with low- and high-fat/sucrose diets. We quantified the plasma and intestinal endocannabinoidome, profiled the gut microbiota, and measured intestinal gene expression related to the immune and the antioxidant responses in the intestinal microenvironment. Overall, we show that intestinal segment-specific microbiota alterations occur following high-fat or low-fat diets enriched or depleted in Se, concomitantly with modifications of circulating endocannabinoidome mediators and changes in cytokine and antioxidant enzyme expression. Specifically, Se enrichment was associated with increased circulating plasma levels of 2-docosahexaenoyl-glycerol (2-DHG), a mediator with putative beneficial actions on metabolism and inflammation. Others eCBome mediators also responded to the diets. Concomitantly, changes in gut microbiota were observed in Se-enriched diets following a high-fat diet, including an increase in the relative abundance of Peptostreptococcaceae and Lactobacillaceae. With respect to the intestinal immune response and anti-oxidative gene expression, we observed a decrease in the expression of proinflammatory genes Il1ß and Tnfα in high-fat Se-enriched diets in caecum, while in ileum an increase in the expression levels of the antioxidant gene Gpx4 was observed following Se depletion. The sex of the animal influenced the response to the diet of both the gut microbiota and endocannabinoid mediators. These results identify Se as a regulator of the gut microbiome and endocannabinoidome in conjunction with high-fat diet, and might be relevant to the development of new nutritional strategies to improve metabolic health and chronic low-grade inflammation associated to metabolic disorders.

Hemp seed significantly modulates the endocannabinoidome and produces beneficial metabolic effects with improved intestinal barrier function and decreased inflammation in mice under a high-fat, high-sucrose diet as compared with linseed.

Omega-3 fatty acids support cardiometabolic health and reduce chronic low-grade inflammation. These fatty acids may impart their health benefits partly by modulating the endocannabinoidome and the gut microbiome, both of which are key regulators of metabolism and the inflammatory response. Whole hemp seeds (Cannabis sativa) are of exceptional nutritional value, being rich in omega-3 fatty acids. We assessed the effects of dietary substitution (equivalent to about 2 tablespoons of seeds a day for humans) of whole hemp seeds in comparison with whole linseeds in a diet-induced obesity mouse model and determined their effects on obesity and the gut microbiome-endocannabinoidome axis. We show that whole hemp seed substitution did not affect weigh gain, adiposity, or food intake, whereas linseed substitution did, in association with higher fasting glucose levels, greater insulin release during an oral glucose tolerance test, and higher levels of liver triglycerides than controls. Furthermore, hemp seed substitution mitigated diet-induced obesity-associated increases in intestinal permeability and circulating PAI-1 levels, while having no effects on markers of inflammation in epididymal adipose tissue, which were, however, increased in mice fed linseeds. Both hemp seeds and linseeds were able to modify the expression of several endocannabinoidome genes and markedly increased the levels of several omega-3 fatty acid-derived endocannabinoidome bioactive lipids with previously suggested anti-inflammatory actions in a tissue specific manner, despite the relatively low level of seed substitution. While neither diet markedly modified the gut microbiome, mice on the hemp seed diet had higher abundance of Clostridiaceae 1 and Rikenellaceae than mice fed linseed or control diet, respectively. Thus, hemp seed-containing foods might represent a source of healthy fats that are not likely to exacerbate the metabolic consequences of obesogenic diets while producing intestinal permeability protective effects and some anti-inflammatory actions.

Effect of hip and knee joint angles on resting hamstring muscles rigidity in men and women.

PURPOSE: Hamstring muscle strains are one of the most common injuries in sports practice, for both men and women. However, sex disparities in the rate of muscle injuries have been observed. As these muscular injuries usually occur at long muscle length, this study aimed to determine the effect of sex on hamstring muscles' resting rigidity under different stretching conditions. METHODS: The shear wave speed (SWS) of resting hamstring muscles was measured in 12 men and 12 women in different hip and knee positions (hip extended with knee flexed, hip flexed with knee extended, both joints extended and both joints flexed). RESULTS: Combining all the positions, the SWS of the semitendinosus was higher in men than in women (2.96 vs. 2.71 m.s-1). Regardless of sex, a significant rise in SWS was systematically observed when the semimembranosus was stretched (1.86, 2.37, 2.76 and 4.39 m.s-1) but it was neither the case for the semitendinosus (p = 0.82) nor for the biceps femoris (p = 0.50). Finally, differences in SWS among the hamstring muscles were only observed at the longest muscle length, with greater SWS values for the semimembranosus and semitendinosus in comparison with the biceps femoris (4.39 and 4.12 vs. 3.38 m.s-1 respectively). CONCLUSION: In conclusion, a sex difference was only observed in the resting semitendinosus rigidity. Independently of sex, the increase in resting hamstring muscles SWS with stretch was muscle specific.

Influence of Repeated-Sprint Ability on the in-Game Activity Profiles of Semiprofessional Rugby Union Players According to Position.

This study investigated the influence of repeated-sprint ability (RSA) on the activity of rugby union players in a competitive situation according to their position. Thirty-three semiprofessional rugby union players (age, 25.6 ± 4.3; height, 184.0 ± 8.0 cm; weight, 98.9 ± 13.9 kg, ~20 h training a week), divided into two position subgroups (forwards n = 20, backs n = 13) or four positional subgroups (front row and locks n = 13, back row n = 7, inside backs n = 6, outside backs n = 7), were tested. Their RSA was assessed with a 12 × 20 m sprint test over a 20 s cycle. GPS data (distance, acceleration, number of sprints, maximum velocity, and high-velocity running) and technical data were collected on 18 semiprofessional division rugby union games. In forwards, players with lower cumulated sprint time in the RSA test produced significantly more accelerations (ρ = -0.85, p < 0.001) and more combat actions per match minute (ρ = -0.69, p < 0.001). In backs, RSA was significantly correlated with high-intensity running [distance (ρ = -0.76), Vmax (ρ = -0.84), sprints frequency (ρ = -0.71), high-velocity running (ρ = -0.76), all p < 0.01]. Then, the players were divided into four subgroups (front row and locks, back row, inside backs and outside backs). RSA was significantly associated with the number of accelerations (ρ = -0.96, p <001) and combat actions in front row and locks (ρ = -0.71, p = 0.007). In the back row, RSA was correlated with distance (ρ = -0.96, p = 0.003) and the frequency of combat actions (ρ = -0.79, p = 0.04). In inside backs, RSA was significantly (all p < 0.01) correlated with distance (ρ = -0.81), number of accelerations (ρ = -0.94) and high-velocity running (ρ = -0.94), while in outside backs, RSA was associated with sprint frequency (ρ = -0.85) and the maximal in-game velocity reached (ρ = -0.89). These results demonstrate that RSA is associated with match running and combat activity performance (i) regardless of the position on the pitch and (ii) specifically for each player's position by improving the corresponding activity profile.

Influence of diet on acute endocannabinoidome mediator levels post exercise in active women, a crossover randomized study.

The extended endocannabinoid system, also termed endocannabinoidome, participates in multiple metabolic functions in health and disease. Physical activity can both have an acute and chronic impact on endocannabinoid mediators, as does diet. In this crossover randomized controlled study, we investigated the influence of diet on the peripheral response to acute maximal aerobic exercise in a sample of active adult women (n = 7) with no underlying metabolic conditions. We compared the impact of 7-day standardized Mediterranean diet (MedDiet) and control diet inspired by Canadian macronutrient intake (CanDiet) on endocannabinoidome and short-chain fatty acid metabolites post maximal aerobic exercise. Overall, plasmatic endocannabinoids, their congeners and some polyunsaturated fatty acids increased significantly post maximal aerobic exercise upon cessation of exercise and recovered their initial values within 1 h after exercise. Most N-acylethanolamines and polyunsaturated fatty acids increased directly after exercise when the participants had consumed the MedDiet, but not when they had consumed the CanDiet. This impact was different for monoacylglycerol endocannabinoid congeners, which in most cases reacted similarly to acute exercise while on the MedDiet or the CanDiet. Fecal microbiota was only minimally affected by the diet in this cohort. This study demonstrates that endocannabinoidome mediators respond to acute maximal aerobic exercise in a way that is dependent on the diet consumed in the week prior to exercise.

Impact of the Menstrual Cycle Phases on the Movement Patterns of Sub-Elite Women Soccer Players during Competitive Matches.

The purpose of this study was to evaluate the influence of the menstrual cycle phases on the movement patterns of sub-elite women soccer players during competitive matches over three consecutive seasons. Individual movement data were analyzed and compared in eight players from the second French League at the early follicular (EF), late follicular (LF) and mid-luteal (ML) phases of their menstrual cycle, determined by the calendar method. The movement patterns, expressed as meters per minute, were recorded during competitive matches using devices placed on the player's ankle. Our results showed significantly lower distances covered at moderate and high velocity in the EF phase than in the LF and ML phases (Cohen's d effect size = 1.03 and 0.79, respectively). The total distance covered during matches and the number of sprints also were reduced during EF compared with LF (d = 0.78 and 0.7, respectively). Overall, the total distance and distance covered at low velocity were significantly lower during the second half-time of the matches (d = 1.51), but no menstrual cycle phase × game period interaction was noted. In conclusion, our study suggests that EF may impact the movement pattern of sub-elite women soccer players during competitive matches, without any modulation of this effect by the playing time. Despite the low sample size, these results can be useful for coaches and support staff to modulate training loads and player rotation during soccer games.

Lower Muscle and Blood Lactate Accumulation in Sickle Cell Trait Carriers in Response to Short High-Intensity Exercise.

It remains unclear whether sickle cell trait (SCT) should be considered a risk factor during intense physical activity. By triggering the polymerization-sickling-vaso-occlusion cascade, lactate accumulation-associated acidosis in response to high-intensity exercise is believed to be one of the causes of complications. However, our understanding of lactate metabolism in response to high-intensity exercise in SCT carriers is incomplete. Thirty male SCT carriers (n = 15) and healthy subjects (n = 15) with and without α-thalassemia performed a 2-min high-intensity exercise. Blood and muscle lactate concentrations were measured at exercise completion. Time courses of blood lactate and glucose concentrations were followed during the subsequent recovery. Additional biochemical analyses were performed on biopsies of the vastus lateralis muscle. SCT was associated with lower blood and muscle lactate concentrations in response to the short high-intensity exercise. Compared to controls, the muscle content among SCT carriers of lactate transporter MCT4 and ß2-adrenergic receptor were higher and lower, respectively. During recovery, the lactate removal ability was higher in SCT carriers. In the present study, no effect of α-thalassemia was observed. The lower blood and muscle lactate accumulations in SCT carriers may, to some extent, act as protective mechanisms: (i) against exercise-related acidosis and subsequent sickling, that may explain the relatively rare complications observed in exercising SCT carriers; and (ii) against the deleterious effects of intracellular lactate and associated acidosis on muscle function, that might explain the elevated presence of SCT carriers among the best sprinters.

Pilot study of repeated blood-brain barrier disruption in patients with mild Alzheimer's disease with an implantable ultrasound device.

BACKGROUND: Temporary disruption of the blood-brain barrier (BBB) using pulsed ultrasound leads to the clearance of both amyloid and tau from the brain, increased neurogenesis, and mitigation of cognitive decline in pre-clinical models of Alzheimer's disease (AD) while also increasing BBB penetration of therapeutic antibodies. The goal of this pilot clinical trial was to investigate the safety and efficacy of this approach in patients with mild AD using an implantable ultrasound device. METHODS: An implantable, 1-MHz ultrasound device (SonoCloud-1) was implanted under local anesthesia in the skull (extradural) of 10 mild AD patients to target the left supra-marginal gyrus. Over 3.5 months, seven ultrasound sessions in combination with intravenous infusion of microbubbles were performed twice per month to temporarily disrupt the BBB. 18F-florbetapir and 18F-fluorodeoxyglucose positron emission tomography (PET) imaging were performed on a combined PET/MRI scanner at inclusion and at 4 and 8 months after the initiation of sonications to monitor the brain metabolism and amyloid levels along with cognitive evaluations. The evolution of cognitive and neuroimaging features was compared to that of a matched sample of control participants taken from the Alzheimer's Disease Neuroimaging Initiative (ADNI). RESULTS: A total of 63 BBB opening procedures were performed in nine subjects. The procedure was well-tolerated. A non-significant decrease in amyloid accumulation at 4 months of - 6.6% (SD = 7.2%) on 18F-florbetapir PET imaging in the sonicated gray matter targeted by the ultrasound transducer was observed compared to baseline in six subjects that completed treatments and who had evaluable imaging scans. No differences in the longitudinal change in the glucose metabolism were observed compared to the neighboring or contralateral regions or to the change observed in the same region in ADNI participants. No significant effect on cognition evolution was observed in comparison with the ADNI participants as expected due to the small sample size and duration of the trial. CONCLUSIONS: These results demonstrate the safety of ultrasound-based BBB disruption and the potential of this technology to be used as a therapy for AD patients. Research of this technique in a larger clinical trial with a device designed to sonicate larger volumes of tissue and in combination with disease-modifying drugs may further enhance the effects observed. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03119961.

The interaction of secreted phospholipase A2-IIA with the microbiota alters its lipidome and promotes inflammation.

Secreted phospholipase A2-IIA (sPLA2-IIA) hydrolyzes phospholipids to liberate lysophospholipids and fatty acids. Given its poor activity toward eukaryotic cell membranes, its role in the generation of proinflammatory lipid mediators is unclear. Conversely, sPLA2-IIA efficiently hydrolyzes bacterial membranes. Here, we show that sPLA2-IIA affects the immune system by acting on the intestinal microbial flora. Using mice overexpressing transgene-driven human sPLA2-IIA, we found that the intestinal microbiota was critical for both induction of an immune phenotype and promotion of inflammatory arthritis. The expression of sPLA2-IIA led to alterations of the intestinal microbiota composition, but housing in a more stringent pathogen-free facility revealed that its expression could affect the immune system in the absence of changes to the composition of this flora. In contrast, untargeted lipidomic analysis focusing on bacteria-derived lipid mediators revealed that sPLA2-IIA could profoundly alter the fecal lipidome. The data suggest that a singular protein, sPLA2-IIA, produces systemic effects on the immune system through its activity on the microbiota and its lipidome.

Human and Mouse Eosinophils Differ in Their Ability to Biosynthesize Eicosanoids, Docosanoids, the Endocannabinoid 2-Arachidonoyl-glycerol and Its Congeners.

High eosinophil (EOS) counts are a key feature of eosinophilic asthma. EOS notably affect asthmatic response by generating several lipid mediators. Mice have been utilized in hopes of defining new pharmacological targets to treat asthma. However, many pinpointed targets in mice did not translate into clinics, underscoring that key differences exist between the two species. In this study, we compared the ability of human (h) and mouse (m) EOS to biosynthesize key bioactive lipids derived from arachidonic acid (AA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). hEOS were isolated from the blood of healthy subjects and mild asthmatics, while mEOSs were differentiated from the bone marrow. EOSs were treated with fatty acids and lipid mediator biosynthesis assessed by LC-MS/MS. We found that hEOS biosynthesized leukotriene (LT) C4 and LTB4 in a 5:1 ratio while mEOS almost exclusively biosynthesized LTB4. The biosynthesis of the 15-lipoxygenase (LO) metabolites 15-HETE and 12-HETE also differed, with a 15-HETE:12-HETE ratio of 6.3 for hEOS and 0.727 for mEOS. EOS biosynthesized some specialized pro-resolving mediators, and the levels from mEOS were 9-times higher than those of hEOS. In contrast, hEOS produced important amounts of the endocannabinoid 2-arachidonoyl-glycerol (2-AG) and its congeners from EPA and DHA, a biosynthetic pathway that was up to ~100-fold less prominent in mEOS. Our data show that hEOS and mEOS biosynthesize the same lipid mediators but in different amounts. Compared to asthmatics, mouse models likely have an amplified involvement of LTB4 and specialized pro-resolving mediators and a diminished impact of the endocannabinoid 2-arachidonoyl-glycerol and its congeners.

α-Linolenic acid and linoleic acid modulate the lipidome and the skin barrier of a tissue-engineered skin model.

Polyunsaturated fatty acids (PUFAs) play an important role in the establishment and the maintenance of the skin barrier function. However, the impact of their derived lipid mediators remains unclear. Skin substitutes were engineered according to the self-assembly method with a culture medium supplemented with 10 µM of both α-linolenic acid (ALA) and linoleic acid (LA). The supplementation with ALA and LA decreased testosterone absorption through a tissue-engineered reconstructed skin model, thus indicating an improved skin barrier function following supplementation. The exogenously provided fatty acids were incorporated into the phospholipid and triglyceride fractions of the skin substitutes. Indeed, the dual supplementation increased the levels of eicosapentaenoic acid (EPA) (15-fold), docosapentaenoic acid (DPA) (3-fold), and LA (1.5-fold) in the epidermal phospholipids while it increased the levels of ALA (>20-fold), DPA (3-fold) and LA (1.5-fold) in the epidermal triglycerides. The bioactive lipid mediator profile of the skin substitutes, including prostaglandins, hydroxy-fatty acids, N-acylethanolamines and monoacylglycerols, was next analyzed using liquid chromatography-tandem mass spectrometry. The lipid supplementation further modulated bioactive lipid mediator levels of the reconstructed skin substitutes, leading to a lipid mediator profile more representative of the one found in normal human skin. These findings show that an optimized supply of PUFAs via culture media is essential for the establishment of improved barrier function in vitro. STATEMENT OF SIGNIFICANCE: Supplementation of the culture medium with 10 µM of both α-linolenic acid (ALA) and linoleic acid (LA) improved the skin barrier function of a tissue-engineered skin model. The exogenously provided fatty acids were incorporated into the phospholipid and triglyceride fractions of the skin substitutes and further modulated bioactive lipid mediator levels, including prostaglandins, hydroxy-fatty acids, N-acylethanolamines and monoacylglycerols. These findings highlight the important role of ALA and LA in skin homeostasis and show that an optimized supply of polyunsaturated fatty acids via culture media is essential for the establishment of improved barrier function in vitro.

Assessment of the Effects of Dietary Vitamin D Levels on Olanzapine-Induced Metabolic Side Effects: Focus on the Endocannabinoidome-Gut Microbiome Axis.

Vitamin D deficiency is associated with poor mental health and dysmetabolism. Several metabolic abnormalities are associated with psychotic diseases, which can be compounded by atypical antipsychotics that induce weight gain and insulin resistance. These side-effects may be affected by vitamin D levels. The gut microbiota and endocannabinoidome (eCBome) are significant regulators of both metabolism and mental health, but their role in the development of atypical antipsychotic drug metabolic side-effects and their interaction with vitamin D status is unknown. We studied the effects of different combinations of vitamin D levels and atypical antipsychotic drug (olanzapine) exposure on whole-body metabolism and the eCBome-gut microbiota axis in female C57BL/6J mice under a high fat/high sucrose (HFHS) diet in an attempt to identify a link between the latter and the different metabolic outputs induced by the treatments. Olanzapine exerted a protective effect against diet-induced obesity and insulin resistance, largely independent of dietary vitamin D status. These changes were concomitant with olanzapine-mediated decreases in Trpv1 expression and increases in the levels of its agonists, including various N-acylethanolamines and 2-monoacylglycerols, which are consistent with the observed improvement in adiposity and metabolic status. Furthermore, while global gut bacteria community architecture was not altered by olanzapine, we identified changes in the relative abundances of various commensal bacterial families. Taken together, changes of eCBome and gut microbiota families under our experimental conditions might contribute to olanzapine and vitamin D-mediated inhibition of weight gain in mice on a HFHS diet.

Biosynthesis of the Novel Endogenous 15-Lipoxygenase Metabolites N-13-Hydroxy-octodecadienoyl-ethanolamine and 13-Hydroxy-octodecadienoyl-glycerol by Human Neutrophils and Eosinophils.

The endocannabinoids 2-arachidonoyl-glycerol and N-arachidonoyl-ethanolamine are lipids regulating many physiological processes, notably inflammation. Endocannabinoid hydrolysis inhibitors are now being investigated as potential anti-inflammatory agents. In addition to 2-arachidonoyl-glycerol and N-arachidonoyl-ethanolamine, the endocannabinoidome also includes other monoacylglycerols and N-acyl-ethanolamines such as 1-linoleoyl-glycerol (1-LG) and N-linoleoyl-ethanolamine (LEA). By increasing monoacylglycerols and/or N-acyl-ethanolamine levels, endocannabinoid hydrolysis inhibitors will likely increase the levels of their metabolites. Herein, we investigated whether 1-LG and LEA were substrates for the 15-lipoxygenase pathway, given that both possess a 1Z,4Z-pentadiene motif, near their omega end. We thus assessed how human eosinophils and neutrophils biosynthesized the 15-lipoxygenase metabolites of 1-LG and LEA. Linoleic acid (LA), a well-documented substrate of 15-lipoxygenases, was used as positive control. N-13-hydroxy-octodecadienoyl-ethanolamine (13-HODE-EA) and 13-hydroxy-octodecadienoyl-glycerol (13-HODE-G), the 15-lipoxygenase metabolites of LEA and 1-LG, were synthesized using Novozym 435 and soybean lipoxygenase. Eosinophils, which express the 15-lipoxygenase-1, metabolized LA, 1-LG, and LEA into their 13-hydroxy derivatives. This was almost complete after five minutes. Substrate preference of eosinophils was LA > LEA > 1-LG in presence of 13-HODE-G hydrolysis inhibition with methyl-arachidonoyl-fluorophosphonate. Human neutrophils also metabolized LA, 1-LG, and LEA into their 13-hydroxy derivatives. This was maximal after 15-30 s. Substrate preference was LA ≫ 1-LG > LEA. Importantly, 13-HODE-G was found in humans and mouse tissue samples. In conclusion, our data show that human eosinophils and neutrophils metabolize 1-LG and LEA into the novel endogenous 15-lipoxygenase metabolites 13-HODE-G and 13-HODE-EA. The full biological importance of 13-HODE-G and 13-HODE-EA remains to be explored.