Higher Plasma Myo-Inositol in Pregnancy Associated with Reduced Postpartum Blood Loss: Secondary Analyses of the NiPPeR Trial.

We previously reported that a combined myo-inositol, probiotics, and enriched micronutrient supplement (intervention) taken preconception and in pregnancy reduced postpartum blood loss (PBL) and major postpartum hemorrhage compared with a standard micronutrient supplement (control), as secondary outcomes of the NiPPeR trial. This study aimed to identify the intervention components that may contribute to this effect. Associations of plasma concentrations of myo-inositol and vitamins B2, B6, B12, and D at preconception (before and after supplementation), early (~7-weeks), and late pregnancy (~28-weeks) with PBL were assessed by multiple linear regression, adjusting for site, ethnicity, preconception BMI, parity, and previous cesarean section. Amongst 583 women, a higher concentration of myo-inositol in early pregnancy was associated with a PBL reduction [ßadj -1.26 (95%CI -2.23, -0.29) mL per µmol/L myo-inositol increase, p = 0.011]. Applying this co-efficient to the increase in mean 7-week-myo-inositol concentration of 23.4 µmol/L with the intervention equated to a PBL reduction of 29.5 mL (~8.4% of mean PBL of 350 mL among controls), accounting for 84.3% of the previously reported intervention effect of 35 mL. None of the examined vitamins were associated with PBL. Therefore, myo-inositol may be a key intervention component mediating the PBL reduction. Further work is required to determine the mechanisms involved.

Higher early pregnancy plasma myo-inositol associates with increased postprandial glycaemia later in pregnancy: Secondary analyses of the NiPPeR randomized controlled trial.

AIM: Myo-inositol supplementation from ~13 weeks' gestation reportedly improves glycaemia regulation in metabolically at-risk women, with speculation that earlier supplementation might bring further improvement. However, the NiPPeR trial of a myo-inositol-containing supplement starting preconception did not lower gestational glycaemia in generally healthy women. We postulated that the earlier timing of supplementation influences the maternal metabolic adaptation for gestational glycaemia regulation. METHODS: In total, 585 women were recruited from Singapore, UK and New Zealand for the NiPPeR study. We examined associations of plasma myo-inositol concentrations at 7 and 28 weeks' gestation with 28 weeks plasma glucose (PG; fasting, and 1 h and 2 h in 75 g oral glucose tolerance test) and insulin indices using linear regression adjusting for covariates. RESULTS: Higher 7-week myo-inositol, but not 28-week myo-inositol, associated with higher 1 h PG [ßadj (95% confidence intervals) 0.05 (0.01, 0.09) loge mmol/L per loge µmol/L, p = .022] and 2 h PG [0.08 (0.03, 0.12), p = .001]; equivalent to 0.39 mmol/L increase in 2 h PG for an average 7-week myo-inositol increase of 23.4 µmol/L with myo-inositol supplementation. Higher 7-week myo-inositol associated with a lower 28-week Stumvoll index (first phase), an approximation of insulin secretion [-0.08 (-0.15, -0.01), p = .020] but not with 28-week Matsuda insulin sensitivity index. However, the clinical significance of a 7-week myo-inositol-related increase in glycaemia was limited as there was no association with gestational diabetes risk, birthweight and cord C-peptide levels. In-silico modelling found higher 28-week myo-inositol was associated with lower gestational glycaemia in White, but not Asian, women after controlling for 7-week myo-inositol effects. CONCLUSION: To our knowledge, our study provides the first evidence that increasing first trimester plasma myo-inositol may slightly exacerbate later pregnancy post-challenge glycaemia, indicating that the optimal timing for starting prenatal myo-inositol supplementation needs further investigation.

Magnesium stable isotope composition, but not concentration, responds to obesity and early insulin-resistant conditions in minipig.

Hypomagnesemia is frequently associated with type 2 diabetes and generally correlates with unfavorable disease progression, but the magnesium status in pre-diabetic conditions remains unclear. Here, the magnesium metabolism is scrutinized in a minipig model of obesity and insulin resistance by measuring variations of the metallome-the set of inorganic elements-and the magnesium stable isotope composition in six organs of lean and obese minipigs raised on normal and Western-type diet, respectively. We found that metallomic variations are most generally insensitive to lean or obese phenotypes. The magnesium stable isotope composition of plasma, liver, kidney, and heart in lean minipigs are significantly heavier than in obese minipigs. For both lean and obese minipigs, the magnesium isotope composition of plasma and liver were negatively correlated to clinical phenotypes and plasma lipoproteins concentration as well as positively correlated to hyperinsulinemic-euglycemic clamp output. Because the magnesium isotope composition was not associated to insulin secretion, our results suggest that it is rather sensitive to whole body insulin sensitivity, opening perspectives to better comprehend the onset of insulin-resistant diabetic conditions.

Sustained reduction of serum neurofilament light chain over 7 years by alemtuzumab in early relapsing-remitting MS.

BACKGROUND: Alemtuzumab efficacy and safety was demonstrated in CARE-MS I and extension studies (CAMMS03409; TOPAZ). OBJECTIVE: Evaluate serum neurofilament light chain (sNfL) in CARE-MS I patients and highly active disease (HAD) subgroup, over 7 and 2 years for alemtuzumab and subcutaneous interferon beta-1a (SC IFNB-1a), respectively. METHODS: Patients received SC IFNB-1a 44 µg 3×/week or alemtuzumab 12 mg/day at baseline and month 12, with further as-needed 3-day courses. sNfL was measured using single-molecule array (Simoa™). HAD definition was ⩾2 relapses in year before randomization and ⩾1 baseline gadolinium-enhancing lesion. RESULTS: Baseline median sNfL levels were similar in alemtuzumab (n = 354) and SC IFNB-1a-treated (n = 159) patients (31.7 vs 31.4 pg/mL), but decreased with alemtuzumab versus SC IFNB-1a until year 2 (Y2; 13.2 vs 18.7 pg/mL; p < 0.0001); 12.7 pg/mL for alemtuzumab at Y7. Alemtuzumab-treated patients had sNfL at/below healthy control median at Y2 (72% vs 47%; p < 0.0001); 73% for alemtuzumab at Y7. HAD patients (n = 102) had higher baseline sNfL (49.4 pg/mL) versus overall population; alemtuzumab HAD patients attained similar levels (Y2, 12.8 pg/mL; Y7, 12.7 pg/mL; 75% were at/below control median at Y7). CONCLUSION: Alemtuzumab was superior to SC IFNB-1a in reducing sNfL, with levels in alemtuzumab patients remaining stable through Y7. CLINICALTRIALS.GOV IDENTIFIER: NCT00530348, NCT00930553, NCT02255656.

A Whole-Grain Diet Increases Whole-Body Protein Balance Compared with a Macronutrient-Matched Refined-Grain Diet.

BACKGROUND: There are limited data from randomized control trials to support or refute the contention that whole-grains can enhance protein metabolism in humans. OBJECTIVES: To examine: 1) the clinical effects of a whole-grain diet on whole-body protein turnover; 2) the cellular effects of whole-grains on protein synthesis in skeletal muscle cells; and 3) the population effects of whole-grain intake on age-related muscle loss. METHODS: Adults with overweight/obesity (n = 14; age = 40 ± 7 y; BMI = 33 ± 5 kg/m2) were recruited into a crossover, randomized controlled trial (NCT01411540) in which isocaloric, macronutrient-matched whole-grain and refined-grain diets were fully provisioned for two 8-wk periods. Diets differed only in the presence of whole-grains (50 g/1000 kcal). Whole-body protein kinetics were assessed at baseline and after each diet in the fasted-state (13C-leucine) and integrated over 24 h (15N-glycine). In vitro studies using C2C12 cells assessed global protein synthesis by surface sensing of translation and anabolic signaling by Western blot. Complementary epidemiological assessments using the NHANES database assessed the effect of whole-grain intake on muscle function assessed by gait speed in older adults (n = 2783). RESULTS: Integrated 24-h net protein balance was 3-fold higher on a whole-grain diet compared with a refined-grain diet (P = 0.04). A whole-grain wheat extract increased submaximal rates of global protein synthesis (27%, P < 0.05) in vitro. In a large sample of older adults, whole-grain intake was associated with greater muscle function (OR = 0.92; 95% CI: 0.86, 0.98). CONCLUSIONS: Consuming 50 g/1000 kcal whole-grains per day promotes greater protein turnover and enhances net protein balance in adults. Whole-grains impact skeletal muscle at the cellular level, and are associated with greater muscle function in older adults. Collectively, these data point to a new mechanism whereby whole-grain consumption favorably enhances protein turnover and improves health outcomes.This clinical trial is registered on clinicaltrials.gov (identifier: NCT01411540).

Body composition assessment in children with inflammatory bowel disease: A comparison of different methods.

AIM: To assess different techniques to measure body composition in paediatric patients with inflammatory bowel disease using dual energy X-ray absorptiometry as a reference method. We hypothesised that a three-compartment model may demonstrate superiority over other methods as skinfold thickness equations and bioelectrical impedance analysis. METHODS: Body composition was assessed using skinfold thickness equations, bioelectrical impedance analysis and the three-compartment model. Data obtained with these methods were compared to the results obtained by dual energy X-ray absorptiometry. Statistical analysis was performed using Spearman's correlation and Bland-Altman's limits of agreement method. RESULTS: Twenty-one paediatric patients with inflammatory bowel disease were included: 11 females and 10 males; mean age for the entire group: 14.3 years, range 12-16 years. In children with inflammatory bowel disease, skinfold thickness equations, bioelectrical impedance analysis and the three-compartment model showed reliable measurements with small differences in the percentage of total body fat and good limits of agreements. CONCLUSION: The assessment of body composition using bioelectrical impedance analysis provides a valid and accurate method in children with inflammatory bowel disease as compared to dual energy X-ray absorptiometry. In the future, superiority of 3-compartment model in research and clinical settings of nutritional intervention and disease status in children with inflammatory bowel disease remains to be demonstrated.

Determination of magnesium isotopic ratios of biological reference materials via multi-collector inductively coupled plasma mass spectrometry.

RATIONALE: Despite a wide range of potential applications, magnesium (Mg) isotope composition has been so far sparsely measured in reference materials with a biological matrix, which is important for the quality control of the results. We describe a method enabling the chemical separation of Mg in geological and biological materials and the determination of its stable isotope composition. METHODS: Different geological (BHVO-1, BHVO-2, BCR-1, and IAPSO) and biological (SRM-1577c, BCR-383, BCR380R, ERM-CE464, DORM-2, DORM-4, TORT-3, and FBS) reference materials were used to test the performance of a new sample preparation procedure for Mg isotopic analysis. The procedure consisted of a simple three-stage elution method to separate Mg from the matrix. Mg isotopic analyses were performed in two different laboratories and with three different multi-collector inductively coupled plasma mass spectrometry instruments. RESULTS: The biological reference materials show a wide range of δ26 Mg values (relative to DSM3 standard), spanning over 2‰, from 0.52 ± 0.29‰ (2SD, n = 7) in bovine liver (SRM-1577c) to -1.45 ± 0.20‰ (2SD, n = 5) in tuna fish (ERM-CE464), with an external precision of 0.03‰ (2SD, n = 85). CONCLUSIONS: This study indicates that isotopic measurements of Mg in biological reference materials show good performance, with the results being within the accepted range. We confirmed that δ26 Mg values in liver are the most positive of all biological materials reported so far.

A ketogenic drink improves cognition in mild cognitive impairment: Results of a 6-month RCT.

INTRODUCTION: Counteracting impaired brain glucose metabolism with ketones may improve cognition in mild cognitive impairment (MCI). METHODS: Cognition, plasma ketone response, and metabolic profile were assessed before and 6 months after supplementation with a ketogenic drink containing medium chain triglyceride (ketogenic medium chain triglyceride [kMCT]; 15 g twice/day; n = 39) or placebo (n = 44). RESULTS: Free and cued recall (Trial 1; P = .047), verbal fluency (categories; P = .024), Boston Naming Test (total correct answers; P = .033), and the Trail-Making Test (total errors; P = .017) improved significantly in the kMCT group compared to placebo (analysis of covariance; pre-intervention score, sex, age, education, and apolipoprotein E4 as covariates). Some cognitive outcomes also correlated positively with plasma ketones. Plasma metabolic profile and ketone response were unchanged. CONCLUSIONS: This kMCT drink improved cognitive outcomes in MCI, at least in part by increasing blood ketone level. These data support further assessment of MCI progression to Alzheimer's disease.

Mineral and Amino Acid Profiling of Different Hematopoietic Populations from the Mouse Bone Marrow.

Steady hematopoiesis is essential for lifelong production of all mature blood cells. Hematopoietic stem and progenitor cells (HSPCs) found in the bone marrow ensure hematopoietic homeostasis in an organism. Failure of this complex process, which involves a fine balance of self-renewal and differentiation fates, often result in severe hematological conditions such as leukemia and lymphoma. Several molecular and metabolic programs, internal or in close interaction with the bone marrow niche, have been identified as important regulators of HSPC function. More recently, nutrient sensing pathways have emerged as important modulators of HSC homing, dormancy, and function in the bone marrow. Here we describe a method for reliable measurement of various amino acids and minerals in different rare bone marrow (BM) populations, namely HSPCs. We found that the amino acid profile of the most primitive hematopoietic compartments (KLS) did not differ significantly from the one of their direct progenies (common myeloid progenitor CMP), while granulocyte-monocyte progenitors (GMPs), on the opposite of megakaryocyte-erythroid progenitors (MEPs), have higher content of the majority of amino acids analyzed. Additionally, we identified intermediates of the urea cycle to be differentially expressed in the KLS population and were found to lower mitochondrial membrane potential, an established readout on self-renewal capability. Moreover, we were able to profile for the first time 12 different minerals and detect differences in elemental contents between different HSPC compartments. Importantly, essential dietary trace elements, such as iron and molybdenum, were found to be enriched in granulocyte-monocyte progenitors (GMPs). We envision this amino acid and mineral profiling will allow identification of novel metabolic and nutrient sensing pathways important in HSPC fate regulation.

Plasma and urinary inositol isomer profiles measured by UHPLC-MS/MS reveal differences in scyllo-inositol levels between non-pregnant and pregnant women.

Previous studies support that myo- and D-chiro-inositol isomers are promising bioactives for the treatment of women with polycystic ovary syndrome and for lowering the risk of gestational diabetes mellitus in pregnant women, whereas scyllo-inositol may have some benefits for neurological disorders (e.g., Alzheimer's disease). Though potentially useful to better understand inositol isomer metabolism and study their role in health and disease, routine analysis of inositol isomers in plasma and urine with a single analytical method is not yet feasible due to the lack of a suitable analytical assay. To address this, we developed and validated a robust ultra-high-performance-liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method for the quantification of inositol isomers in plasma and urine. This method resolves seven inositol isomers with accurate quantification of total chiro- (D and L enantiomers), myo-, and scyllo-inositols and is semi-quantitative for neo-inositol. For urine and plasma myo-inositol, the method repeatability and intermediate reproducibility were below 6% and 8%, respectively. Then, for both chiro- and scyllo-inositols, repeatability and intermediate reproducibility were below 10% and 14%, respectively. A pilot study was carried out to quantify and compare the pattern of inositol isomers in urine and plasma of non-pregnant and pregnant women and showed for the first time that urinary myo- and scyllo-inositol concentrations were significantly higher for women in the third trimester of pregnancy compared with non-pregnant women. These findings warrant further research to understand the biological significance of the observed differences in inositol profiles and suggest a potential role of scyllo-inositol.Graphical abstract Plasma and urinary inositol isomer profiles measured by UHPLC-MS/MS reveal differences in scyllo-inositol levels between non-pregnant and pregnant women.

Multielemental Analysis of Low-Volume Samples Reveals Cancer-Specific Profile in Serum and Sorted Immune Cells.

We developed and validated a reliable, robust, and easy-to-implement quantitative method for multielemental analysis of low-volume samples. Our ICP-MS-based method comprises the analysis of 20 elements (Mg, P, S, K, Ca, V, Cr, Mn, Fe, Co, Cu, Zn, Se, Br, Rb, Sr, Mo, I, Cs, and Ba) in 10 µL of serum and 12 elements (Mg, S, Mn, Fe, Co, Cu, Zn Se, Br, Rb, Mo, and Cs) in less than 250 000 cells. As a proof-of-concept, we analyzed the elemental profiles of serum and sorted immune T cells derived from naïve and tumor-bearing mice. The results indicate a tumor systemic effect on the elemental profiles of both serum and T cells. Our approach highlights promising applications of multielemental analysis in precious samples such as rare cell populations or limited volumes of biofluids that could provide a deeper understanding of the essential role of elements as cofactors in biological and pathological processes.

Total and activity-induced energy expenditure measured during a year in children with inflammatory bowel disease in clinical remission remain lower than in healthy controls.

BACKGROUND: Pediatric inflammatory bowel disease (IBD) is often associated with growth retardation due to malnutrition. However, knowledge on total energy expenditure (TEE), active-induced energy expenditure (AEE) and physical activity remains limited in children with IBD. OBJECTIVE: Assessment of TEE using the doubly labelled water (DLW) method, resting energy expenditure (REE) using indirect calorimetry, and physical activity level using the actigraph GT3X+ in children with IBD (in remission) and healthy controls. METHODS: TEE, REE, AEE and physical activity were measured in 21 children with IBD and 24 healthy controls at baseline. IBD children parameters were monitored further after 6 and 12 months. Predicted REE and TEE values (using Schoefield and the actigraph GT3X+, for REE and TEE respectively) were compared to measured values. RESULTS: Mean ages at baseline were 14.8 ± 1.5 and 13.2 ± 2 years in children with IBD and in healthy control children, respectively. Measured TEEDLW was significantly lower (P < 0.001) in children with IBD compared to the healthy control group. REE corrected by FFM0.5, REE and AEE were also significantly lower in children with IBD. Children with IBD had AEE of 17.5% of TEE and had a significantly higher sedentary behaviour as compared to healthy children. CONCLUSIONS: This study suggests that TEE and AEE are reduced in children with IBD in clinical remission which may result in a reduced moderate and vigorous physical activity level. Our result also highlights that the actigraph GT3X + might give good prediction of TEE in children with IBD at group level but it remains highly variable at individual level.

Metabolism of Exogenous D-Beta-Hydroxybutyrate, an Energy Substrate Avidly Consumed by the Heart and Kidney.

There is growing interest in the metabolism of ketones owing to their reported benefits in neurological and more recently in cardiovascular and renal diseases. As an alternative to a very high fat ketogenic diet, ketones precursors for oral intake are being developed to achieve ketosis without the need for dietary carbohydrate restriction. Here we report that an oral D-beta-hydroxybutyrate (D-BHB) supplement is rapidly absorbed and metabolized in humans and increases blood ketones to millimolar levels. At the same dose, D-BHB is significantly more ketogenic and provides fewer calories than a racemic mixture of BHB or medium chain triglyceride. In a whole body ketone positron emission tomography pilot study, we observed that after D-BHB consumption, the ketone tracer 11C-acetoacetate is rapidly metabolized, mostly by the heart and the kidneys. Beyond brain energy rescue, this opens additional opportunities for therapeutic exploration of D-BHB supplements as a "super fuel" in cardiac and chronic kidney diseases.

A silent agonist of α7 nicotinic acetylcholine receptors modulates inflammation ex vivo and attenuates EAE.

Nicotinic acetylcholine receptors (nAChRs) are best known to function as ligand-gated ion channels in the nervous system. However, recent evidence suggests that nicotine modulates inflammation by desensitizing non-neuronal nAChRs, rather than by inducing channel opening. Silent agonists are molecules that selectively induce the desensitized state of nAChRs while producing little or no channel opening. A silent agonist of α7 nAChRs has recently been shown to reduce inflammation in an animal model of inflammatory pain. The objective of this study was to determine whether a silent agonist of α7 nAChRs can also effectively modulate inflammation and disease manifestation in an animal model of multiple sclerosis. We first evaluated the effects of various nAChR ligands and of an α7 nAChR-selective silent agonist, 1-ethyl-4-(3-(bromo)phenyl)piperazine (m-bromo PEP), on the modulation of mouse bone marrow-derived monocyte/macrophage (BMDM) numbers, phenotype and cytokine production. The non-competitive antagonist mecamylamine and the silent agonist m-bromo PEP reduced pro-inflammatory BMDM numbers by affecting their viability and proliferation. Both molecules also significantly reduced cytokine production by mouse BMDMs and significantly ameliorated disease in experimental autoimmune encephalomyelitis. Finally, m-bromo PEP also reduced chronic inflammatory pain in mice. Taken together, our results further support the hypothesis that nAChRs may modulate inflammation via receptor desensitization rather than channel opening. α7 nAChR-selective silent agonists may thus be a novel source of anti-inflammatory compounds that could be used for the treatment of inflammatory disorders.

Ingestion of a Pre-bedtime Protein Containing Beverage Prevents Overnight Induced Negative Whole Body Protein Balance in Healthy Middle-Aged Men: A Randomized Trial.

Age related muscle wasting leads to overall reductions of lean body mass, reduced muscle strength, and muscle function resulting in compromised quality of life. Utilizing novel nutritional strategies to attenuate such losses is of great importance in elderly individuals. We aimed to test if a complete dietary supplement containing 25 g of milk proteins and ingested in the evening before bed would improve protein metabolism in terms of whole body protein balance over a 10 h overnight period following ingestion of the test drink in healthy middle-aged male subjects. In addition we also assessed the rates of muscle protein synthesis during the second half of the night in order to see if previously reported extended amino acidemia during sleep results in increased rates of muscle protein synthesis. Seventeen healthy middle-aged male subjects (59.4 ± 3.2 year) consumed a dietary supplement drink at 21:00 containing either 25 g milk protein concentrate, 25 g maltodextrin, 7.75 g canola oil (treatment group), or an isocaloric protein void drink (placebo group). Muscle protein synthesis was assessed from a muscle biopsy following the continuous intravenous infusion of 13C-phenylalanine for 5 h (from 03:00 to 08:00). Whole body protein balance was greater in the treatment group (-0.13 ± 11.30 g prot/10 h) compared to placebo (-12.22 ± 6.91 g prot/10 h) (P ≤ 0.01). In contrast, no changes were observed on rates of muscle protein synthesis during the second half of the night. Ingestion of a dietary supplement containing 25 g of milk proteins significantly reduced the negative protein balance observed during the night. Therefore, pre-bedtime protein ingestion may attenuate overnight losses of lean tissue in healthy elderly men. Despite increases in aminoacidemia during the second part of the night, no changes were observed in the rates of muscle protein synthesis during this time. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT02041143.

Vegan and Animal Meal Composition and Timing Influence Glucose and Lipid Related Postprandial Metabolic Profiles.

SCOPE: Flexitarian dieting is increasingly associated with health benefits. The study of postprandial metabolic response to vegan and animal diets is essential to decipher how specific diet components may mediate metabolic changes. METHODS AND RESULTS: A randomized, crossover, controlled vegan versus animal diet challenge is conducted on 21 healthy participants. Postprandial metabolic measurements are conducted at seven timepoints. Area under the curve analysis of the vegan diet response demonstrates higher glucose (EE 0.35), insulin (EE 0.38), triglycerides (EE 0.72), and nine amino acids at breakfast (EE 4.72-209.32); and six lower health-promoting fatty acids at lunch (EE -0.1035 to -0.13) (p < 0.05). CONCLUSIONS: Glycemic and lipid parameters vary irrespective of diet type, demonstrating that vegan and animal meals contain health-promoting and suboptimal nutrient combinations. The vegan breakfast produces the same pattern of elevated branched chain amino acids, insulin, and glucose as the animal diet from the fasting results, reflecting the low protein load in the animal and the higher branched-chain amino acid load of the vegan breakfast. Liberalization of the vegan menu to vegetarian and the animal menu to a Nordic-based diet can result in optimal metabolic signatures for both flexitarian diet strategies in future research.

A Whole-Grain Diet Increases Glucose-Stimulated Insulin Secretion Independent of Gut Hormones in Adults at Risk for Type 2 Diabetes.

INTRODUCTION: The effect of whole-grain (WG) versus refined-grain (RG) diets on glucose-stimulated insulin secretion (GSIS) and ß-cell function is unclear. METHODS: In a double-blind crossover randomized controlled trial, 13 prediabetic adults (37.2 ± 1.8 y, BMI: 33.6 ± 1.4 kg m-2 , 2 h glucose: 146.9 ± 11.6 mg dL-1 ) are provided isocaloric-matched WG and RG diets for 8-weeks each, with an 8-10 week washout between diets. Glucose, insulin, and C-peptide are studied over 240 min following a 75 g OGTT. Incretins (GLP-1 and GIP), PYY, and total ghrelin are assessed at 0, 30, and 60 min. Mixed-meal diets for carbohydrate (54%), fat (28%), and protein (18%) contain either WG (50 g/1000 kcal) or equivalent RG. RESULTS: Both diets induce fat loss (≈2 kg). While neither diet impacts early phase GSIS, the WG diet increases total GSIS (iAUC of C-peptide0-240 /Glc0-240 , p = 0.02) and ß-cell function (disposition index; GSIS × insulin sensitivity, p = 0.02). GIP and PYY are unaltered by either diet, but GLP-1 is higher at 30 min following RG versus WG (p = 0.04). Ghrelin levels are higher at 60 min of the OGTT following both interventions (p = 0.01). CONCLUSION: A WG-rich diet increases ß-cell function independent of gut hormones in adults with prediabetes.

Cortisol does not increase risk of mortality to predation in juvenile bluegill sunfish: A manipulative experimental field study.

The hypothalamic-pituitary-interrenal (HPI) or stress axis in teleost fishes produces their primary glucocorticoid, cortisol. Although generally an adaptive response, prolonged HPI axis stimulation can impair organismal performance. Previous work has shown that stressed teleosts have higher mortality to predation than unstressed conspecifics, suggesting a role for HPI axis in modulating predator-prey interactions. Our current study investigated whether elevated cortisol levels altered the predation rate of a wild teleost fish, the bluegill sunfish (Lepomis macrochirus). Wild juvenile bluegill were given intraperitoneal implants of cocoa butter (i.e., sham), or cocoa butter containing cortisol or cortisol and the glucocorticoid receptor antagonist RU486. After 24 hr, fish were tethered along the bottom of the lake and their survival under natural predation was recorded following 24 hr. A subset of fish was used to validate the efficacy of cortisol implants in this setting. No treatment effect on survival was observed, suggesting that elevated cortisol has minimal involvement in mediating predator-prey interactions in this context. However, experimental fish may have demonstrated resiliency to physiological perturbations owing to the relatively acute duration of our experimental series, and negative effects might be manifested over a more chronic period.

Chronic Plasma Cortisol Elevation Does Not Promote Riskier Behavior in a Teleost Fish: A Test of the Behavioral Resiliency Hypothesis.

Stressed fish have been shown to have higher predator-induced mortality than unstressed conspecifics, suggesting a role for the hypothalamic-pituitary-interrenal axis in modifying risk-taking behaviors. Yet, there is also evidence of behavioral resiliency in the face of chronic stressors. Here, we tested the behavioral resiliency hypothesis, which posits that animals can maintain consistent behavioral phenotypes in the face of significant physiological challenges. We determined whether chronic plasma cortisol elevation promotes risk-taking behaviors in a model teleost fish, the pumpkinseed sunfish (Lepomis gibbosus). Experimental fish were implanted with cocoa butter either as a sham or with cortisol. At 48 h post-implantation, the behavior of individual focal fish was tested in an experimental arena comprising of a simulated physical refuge, an open zone containing a constrained conspecific shoal, and a compartment containing either a model of a northern pike (Esox lucius) paired with corresponding pike olfactory cues in lake water or no pike model (control) paired with sham lake water cues only. The fish were assayed individually for their refuge utilization, shoaling tendency, and general activity. Neither cortisol treatment nor predation-risk treatment influenced any of these behaviors. This suggests that sunfish, in the context of our experiment, were behaviorally resilient to the physiological effects of chronic plasma cortisol elevation and in the face of an apparent threat of predation. Our results thus provide support for the behavioral resiliency hypothesis in fish under both physiological and ecological stressors. We posit that behavioral resiliency is an evolutionary adaptation ensuring appropriate responses to environmental conditions.

Elevação Crônica do Cortisol Plasmático não Promove Comportamento Mais Arriscado em um Peixe Teleósteo: Um teste da Hipótese de Resiliência Comportamental (Chronic Plasma Cortisol Elevation Does Not Promote Riskier Behavior in a Teleost Fish: A Test of the Behavioral Resiliency Hypothesis) Foi demonstrado que peixes estressados têm maior mortalidade causada por predadores do que co-específicos não estressados, sugerindo um papel para o eixo hipotálamo­hipófise­interrenal na modificação de comportamentos de risco. No entanto, há também evidências de resiliência comportamental frente a estressores crônicos. Aqui testamos a hipótese de resiliência comportamental, que postula que os animais podem manter fenótipos comportamentais consistentes frente a desafios fisiológicos significativos. Determinamos se a elevação crônica do cortisol plasmático promove comportamentos de risco em um peixe teleósteo modelo, o perca-sol (Lepomis gibbosus). Peixes experimentais foram implantados com manteiga de cacau, tanto como um placebo ou com cortisol. Após 48 h da implantação, o comportamento de peixes individuais foi testado em uma arena experimental composta por um refúgio simulado, uma zona aberta contendo um cardume co-específico e um compartimento contendo um modelo de lúcio-do-norte (Esox lucius) pareado com as pistas olfativas correspondentes de lúcios em água fluvial ou sem modelo (controle) pareado apenas com iscas falsas. Os peixes foram analisados individualmente quanto à utilização de refúgio, tendência de formar cardumes, e atividade geral. Nem o tratamento com cortisol e nem o com risco de predação influenciaram qualquer um desses comportamentos. Isto sugere que os perca-sol, no contexto do nosso experimento, eram comportamentalmente resilientes aos efeitos fisiológicos da elevação crônica do cortisol plasmático e diante de uma aparente ameaça de predação. Nossos resultados fornecem apoio para a hipótese de resiliência comportamental em peixes sob estressores fisiológicos e ecológicos. Nós postulamos que a resiliência comportamental é uma adaptação evolutiva que garante respostas apropriadas às condições ambientais. translated to Portuguese by G. Sobral (gabisobral@gmail.com).

La Elevación Crónica de Cortisol en el Plasma no Promueve un Comportamiento más Riesgoso en un Pez Teleósteo: Una Prueba de la Hipótesis de Resistencia de Comportamiento (Chronic Plasma Cortisol Elevation Does Not Promote Riskier Behavior in a Teleost Fish: A Test of the Behavioral Resiliency Hypothesis) Se ha demostrado que los peces estresados tienen una mayor mortalidad inducida por depredadores que los conespecíficos no estresados, lo que sugiere un papel para el eje hipotálamo­pituitario­interrenal en la modificación de los compartamientos de riesgo. Sin embargo, también hay evidencia de resistencia del comportamiento frente a los factores estresantes crónicos. Aquí, probamos la hipótesis de resistencia del comportamiento, que postula que los animales pueden mantener fenotipos de comportamiento consistentes ante desafíos fisiológicos significativos. Determinamos si la elevación crónica de cortisol en plasma promueve comportamientos de riesgo en un pez modelo teleósteo, el pez sol de semillas de calabaza (Lepomis gibbosus). Los peces experimentales se implantaron con manteca de cacao como una farsa o con cortisol. A las 48 h posteriores a la implantación, se evaluó el comportamiento de los peces focales individuales en un campo experimental que comprende un refugio físico simulado, una zona abierta que contiene un banco de peces conspecificos constreñidos, y un compartimento que contiene un modelo de lucio norteño (Esox lucius) emparejado con señales olfativas de lucio correspondientes en el agua del lago o sin modelo de lucio (control) emparejado solo con señales de agua del lago simulado. Los peces fueron analizados individualmente por su utilización de refugio, tendencia al cardumen y actividad general. Ninguno de estos comportamientos fuero influidos por el tratamiento con cortisol o el tratamiento de riesgo de depredación. Esto sugiere que los peces sol, en el contexto de nuestro experimento, eran resistentes al comportamiento frente a los efectos fisiológicos de la elevación crónica de cortisol en el plasma y ante una amenaza aparente de depredación. Por lo tanto, nuestros resultados brindan apoyo para la hipótesis de resistencia de comportamiento en peces bajo factores de estrés fisiológicos y ecológicos. Postulamos que la resiliencia conductual es una adaptación evolutiva que garantiza respuestas adecuadas a las condiciones ambientales. translated to Spanish by Y. E. Jimenez (yordano_jimenez@brown.edu).

Effects of protein quantity and type on diet induced thermogenesis in overweight adults: A randomized controlled trial.

BACKGROUND & AIMS: Protein content of a meal is hypothesized to drive DIT dose-dependently. However, no single meal study exists comparing two different doses of protein on DIT. In addition, the source of protein, particularly whey protein, was shown to have a higher DIT than casein and soy in the acute setting, however the mechanism behind this difference is not yet clear. The aim of the present work is therefore to evaluate the efficacy of two different doses and types of protein (whey protein and casein) on DIT in overweight adults. METHODS: Randomized, double blind crossover including seventeen overweight men and women assigned to four isocaloric study treatments where protein and carbohydrate were exchanged: control, 30 g of whey protein microgels (WPM30), 50 g WPM (WPM50) or 50 g micellar casein (MC50). Energy expenditure was measured by indirect calorimetry. Blood, breath and urine samples were collected in order to measure substrate oxidation, amino acid profile, glucose and insulin, protein turnover and other metabolic parameters. RESULTS: DIT was 6.7 ± 3.7%, 13.0 ± 5.0%, 18.0 ± 5.0% and 16.0 ± 5.0% for control, WPM30, WPM50 and MC50, respectively. There was a significant difference between WPM50 and WPM30 (p < 0.005) and a trend was observed between WPM50 and MC50 (p = 0.06). WPM50 resulted in the highest total, essential, and branched-chain plasma amino acid concentrations when compared with the other study treatments (p < 0.005) and a higher insulin concentration than MC50 (p < 0.005). Protein oxidation was higher for WPM50 than MC50. Protein turnover was significantly correlated with DIT through total leucine oxidation (r = 0.52, p = 0.005). CONCLUSIONS: Our findings show that DIT does increase at a dose beyond 30 g of WPM and that the type of dairy protein may have an effect on DIT with WPM tending towards a higher DIT than casein. Although further research is required to understand the mechanism behind the effect of different protein sources on thermogenesis, we suggest that amongst the components of protein turnover, protein oxidation may be an important driver of thermogenesis at doses higher than 30 g. These results have concrete implications when choosing a dose of protein to optimize its thermogenic effect. CLINICAL TRIAL REGISTRY NUMBER: NCT02303080 www.clinicaltrials.gov.