Effect of cortisol on energy expenditure and amino acid metabolism in humans

Metabolic rate and saliva cortisol concentrations in socially housed adolescent guinea pigs

An individual's energetic demands and hence metabolic rate can strongly change during adolescence, a phase characterized by profound morphological, physiological, and endocrine changes. Glucocorticoid hormones (e.g. cortisol) are released in response to hypothalamic-pituitary-adrenal-axis activity, modulate several metabolic processes, and can also be linked to increased metabolic rate. In domestic guinea pigs (Cavia aperea f. porcellus) housed in same-sex groups, cortisol concentrations increase during adolescence in males but remain stable in females, which was suggested to be related to different energetic demands by age. We therefore measured metabolic rate through oxygen (O2) consumption over 2.5 h in male and female guinea pigs housed in same-sex groups during adolescence at ages of 60, 120, and 180 days, which was paralleled by analyses of saliva cortisol concentrations before and after the measurement. The statistical analyses involved whole body metabolic rate (ml O2/h), body mass-corrected metabolic rate (ml O2/h/kg), and body mass-independent metabolic rate (ml O2/h statistically corrected for body mass). We found increasing cortisol concentrations with age in males only, but none of the three metabolic rate analyses revealed a sex difference by age. On the individual level, repeatability across ages was found in metabolic rate as well as in body mass and cortisol concentrations after the measurement, but not in "basal" cortisol concentrations. Our results suggest no sex-specific changes in metabolic rate and hence equal energetic demands in male and female guinea pigs during adolescence. Moreover, metabolic rate clearly represents a highly stable physiological trait already early in a guinea pig's life irrespective of rather fluctuating cortisol concentrations.

Association of adrenal steroids with metabolomic profiles in patients with primary and endocrine hypertension

Introduction

Endocrine hypertension (EHT) due to pheochromocytoma/paraganglioma (PPGL), Cushing's syndrome (CS), or primary aldosteronism (PA) is linked to a variety of metabolic alterations and comorbidities. Accordingly, patients with EHT and primary hypertension (PHT) are characterized by distinct metabolic profiles. However, it remains unclear whether the metabolomic differences relate solely to the disease-defining hormonal parameters. Therefore, our objective was to study the association of disease defining hormonal excess and concomitant adrenal steroids with metabolomic alterations in patients with EHT.

Methods

Retrospective European multicenter study of 263 patients (mean age 49 years, 50% females; 58 PHT, 69 PPGL, 37 CS, 99 PA) in whom targeted metabolomic and adrenal steroid profiling was available. The association of 13 adrenal steroids with differences in 79 metabolites between PPGL, CS, PA and PHT was examined after correction for age, sex, BMI, and presence of diabetes mellitus.

Results

After adjustment for BMI and diabetes mellitus significant association between adrenal steroids and metabolites - 18 in PPGL, 15 in CS, and 23 in PA - were revealed. In PPGL, the majority of metabolite associations were linked to catecholamine excess, whereas in PA, only one metabolite was associated with aldosterone. In contrast, cortisone (16 metabolites), cortisol (6 metabolites), and DHEA (8 metabolites) had the highest number of associated metabolites in PA. In CS, 18-hydroxycortisol significantly influenced 5 metabolites, cortisol affected 4, and cortisone, 11-deoxycortisol, and DHEA each were linked to 3 metabolites.

Discussions

Our study indicates cortisol, cortisone, and catecholamine excess are significantly associated with metabolomic variances in EHT versus PHT patients. Notably, catecholamine excess is key to PPGL's metabolomic changes, whereas in PA, other non-defining adrenal steroids mainly account for metabolomic differences. In CS, cortisol, alongside other non-defining adrenal hormones, contributes to these differences, suggesting that metabolic disorders and cardiovascular morbidity in these conditions could also be affected by various adrenal steroids.

Low thyroxine serves as an upstream regulator of ecophysiological adaptations in Ansell's mole-rats

Introduction

About 10% of all rodent species have evolved a subterranean way of life, although life in subterranean burrows is associated with harsh environmental conditions that would be lethal to most animals living above ground. Two key adaptations for survival in subterranean habitats are low resting metabolic rate (RMR) and core body temperature (Tb). However, the upstream regulation of these traits was unknown thus far. Previously, we have reported exceptionally low concentrations of the thyroid hormone (TH) thyroxine (T4), and peculiarities in TH regulating mechanisms in two African mole-rat species, the naked mole-rat and the Ansell's mole-rat.

Methods

In the present study, we treated Ansell's mole-rats with T4 for four weeks and analyzed treatment effects on the tissue and whole organism level with focus on metabolism and thermoregulation.

Results

We found RMR to be upregulated by T4 treatment but not to the extent that was expected based on serum T4 concentrations. Our data point towards an extraordinary capability of Ansell's mole-rats to effectively downregulate TH signaling at tissue level despite very high serum TH concentrations, which most likely explains the observed effects on RMR. On the other hand, body weight was decreased in T4-treated animals and Tb was upregulated by T4 treatment. Moreover, we found indications of the hypothalamus-pituitary-adrenal axis potentially influencing the treatment effects.

Conclusion

Taken together, we provide the first experimental evidence that the low serum T4 concentrations of Ansell's mole-rats serve as an upstream regulator of low RMR and Tb. Thus, our study contributes to a better understanding of the ecophysiological evolution of the subterranean lifestyle in African mole-rats.

Activities of the hypothalamo-pituitary-adrenal axis and autonomic nervous system following a strong earthquake

This study aimed to investigate the effects of post-traumatic stress, caused by a strong earthquake, on the hypothalamo-pituitary-adrenal axis (HPA) and autonomous nervous system activity (ANS). Activities of the HPA (as salivary cortisol) and ANS (as heart-rate variability [HRV]) were measured following the 2020 Elazig (Türkiye) earthquake (6.8 Richter Scale, classified as strong). A total of 227 participants (103 men (45%) and 124 women (%55)) provided saliva samples twice, namely, 1 week and 6 weeks after the earthquake. Of these participants, HRV was measured in 51 participants by 5 min continuous electrocardiogram (ECG) recording. Frequency- and time-domain parameters of the HRV were calculated to assess the activity of ANS and low/high frequency (LF/HF) ratio was used as surrogate for sympathovagal balance. Salivary cortisol levels decreased from week 1 towards week 6 (17.40 ± 1.48 and 15.32 ± 1.37 ng/mL, respectively, p < 0.05). There were no gender differences (17.99 ± 2.63 and 16.90 ± 1.60 ng/mL, respectively for females and males, p > 0.05) for salivary cortisol levels. There were no differences in time- and frequency domain parameters of the HRV including LF/HF ratio (2.95 ± 0.38 ms2 and 3.60 ± 0.70 ms2 , respectively for week 1 and 6, p > 0.05). The data show that HPA axis activity, but not that of the ANS, remains higher 1 week after the earthquake but decreases afterwards towards the sixth week, suggesting that the HPA axis might be responsible for the long-term effects of a traumatic event like a strong earthquake.

Metabolic rates in female guinea pigs during different reproductive stages

Reproduction in female mammals is characterized by major changes in steroid hormone concentrations, which can be linked to fluctuations in energy expenditure (EE). Estradiol and cortisol can increase EE and metabolic rates (MRs), but knowledge on MR changes during the estrous cycle and gestation is scarce for many species. This also applies to the domestic guinea pig, a species exhibiting an exceptional estrous cycle among rodents. In this study, MRs were measured through oxygen (O2) consumption in female guinea pigs during different reproductive stages. Mean O2 consumption over 2.5 h, resting metabolic rate (RMR, lowest and most stable O2 consumption over 3 min), body mass, fecal estrogen and progesterone, and saliva cortisol concentrations were measured in twelve female guinea pigs in a repeated measurements design during diestrus, estrus, and the second trimester of gestation. In estrus, body mass was significantly lower and estrogen and cortisol concentrations were significantly higher compared to diestrus and gestation. Mean O2 consumption and RMR both were significantly increased in estrus compared to diestrus. Additionally, a positive effect of body mass on MRs detected during diestrus and gestation was not found during estrus. Mean O2 consumption was also higher during gestation compared to diestrus, and a significant increase in cortisol concentrations during the 2.5-h MR measurement was recorded. The results indicate that estrus in guinea pigs is energetically demanding, which probably reflects catabolic effects of estrogens and cortisol that uncoupled MRs from body mass. Knowledge on the energetic requirements associated with different reproductive stages is important for future physiological and behavioral studies on female guinea pigs.

The impact of prolonged fasting on 24h energy metabolism and its 24h rhythmicity in healthy, lean males: A randomized cross-over trial

OBJECTIVE

Human energy expenditure and substrate oxidation are under circadian control and food intake is a time cue for the human biological clock, leading to 24h feeding-fasting cycles in energy and substrate metabolism. In recent years, (intermittent) fasting protocols have also become popular to improve metabolic health. Here, we aimed to investigate the impact of food intake on the 24h patterns of energy metabolism as well as to provide data on the timeline of changes in energy metabolism that occur upon an extended period of fasting.

RESEARCH DESIGN AND METHODS

In a randomized, cross-over design, twelve healthy males underwent a 60h fast which was compared to a 60h fed condition. In the fed condition meals were provided at energy balance throughout the study. Conditions were separated by a two week period of habitual diet. Volunteers resided in a respiration chamber for the entire 60h to measure energy expenditure and substrate oxidation hour by hour. Volunteers performed a standardized activity protocol while in the chamber. Blood samples were drawn after 12, 36 and 60h.

RESULTS

Immediately following the breakfast meal (in the fed condition), fat oxidation became higher in the fasted condition compared to the fed condition and remained elevated throughout the study period. The initial rapid increase in fat oxidation corresponded with a decline in the hepatokine activin A (r = -0.86, p = 0.001). The contribution of fat oxidation to total energy expenditure gradually increased with extended abstinence from food, peaking after 51h of fasting at 160 mg/min. Carbohydrate oxidation stabilized at a low level during the second day of fasting and averaged around 60 mg/min with only modest elevations in response to physical activity. Although 24h energy expenditure was significantly lower with prolonged fasting (11.0 ± 0.4 vs 9.8 ± 0.2 and 10.9 ± 0.3 vs 10.3 ± 0.3 MJ in fed vs fasting, day 2 and 3 respectively, p < 0.01), the 24h fluctuations in energy expenditure were comparable between the fasted and fed condition. The fluctuations in substrate oxidation were, however, significantly (p < 0.001 for both carbohydrate and fat oxidation) altered in the fasted state, favouring fat oxidation.

CONCLUSIONS

Energy expenditure displays a day-night rhythm, which is independent of food intake. In contrast, the day-night rhythm of both carbohydrate and fat oxidation is mainly driven by food intake. Upon extended fasting, the absolute rate of fat oxidation rapidly increases and keeps increasing during a 60h fast, whereas carbohydrate oxidation becomes progressively diminished.

TRIAL REGISTRATION

www.trialregister.nl NTR 2042.

Effect of high-dose glucocorticoid treatment on human brown adipose tissue activity: a randomised, double-blinded, placebo-controlled cross-over trial in healthy men

BACKGROUND

Glucocorticoids (GCs) are widely applied anti-inflammatory drugs that are associated with adverse metabolic effects including insulin resistance and weight gain. Previous research indicates that GCs may negatively impact brown adipose tissue (BAT) activity in rodents and humans.

METHODS

We performed a randomised, double-blinded cross-over trial in 16 healthy men (clinicaltrials.govNCT03269747). Participants received 40 mg of prednisone per day for one week or placebo. After a washout period of four weeks, participants crossed-over to the other treatment arm. Primary endpoint was the increase in resting energy expenditure (EE) in response to a mild-cold stimulus (cold-induced thermogenesis, CIT). Secondary outcomes comprised mean 18F-FDG uptake into supraclavicular BAT (SUVmean) as determined by FDG-PET/CT, volume of the BAT depot as well as fat content determined by MRI. The plasma metabolome and the transcriptome of supraclavicular BAT and of skeletal muscle biopsies after each treatment period were analysed.

FINDINGS

Sixteen participants were recruited to the trial and completed it successfully per protocol. After prednisone treatment resting EE was higher both during warm and cold conditions. However, CIT was similar, 153 kcal/24 h (95% CI 40-266 kcal/24 h) after placebo and 186 kcal/24 h (95% CI 94-277 kcal/24 h, p = 0.38) after prednisone. SUVmean of BAT after cold exposure was not significantly affected by prednisone (3.36 g/ml, 95% CI 2.69-4.02 g/ml, vs 3.07 g/ml, 95% CI 2.52-3.62 g/ml, p = 0.28). Results of plasma metabolomics and BAT transcriptomics corroborated these findings. RNA sequencing of muscle biopsies revealed higher expression of genes involved in calcium cycling. No serious adverse events were reported and adverse events were evenly distributed between the two treatments.

INTERPRETATION

Prednisone increased EE in healthy men possibly by altering skeletal muscle calcium cycling. Cold-induced BAT activity was not affected by GC treatment, which indicates that the unfavourable metabolic effects of GCs are independent from thermogenic adipocytes.

FUNDING

Grants from Swiss National Science Foundation (PZ00P3_167823), Bangerter-Rhyner Foundation and from Nora van der Meeuwen-Häfliger Foundation to MJB. A fellowship-grant from the Swiss National Science Foundation (SNF211053) to WS. Grants from German Research Foundation (project number: 314061271-TRR 205) and Else Kröner-Fresenius (grant support 2012_A103 and 2015_A228) to MR.

Severe COVID-19 associated hyperglycemia is caused by beta cell dysfunction: a prospective cohort study

BACKGROUND

COVID-19, an infectious disease caused by SARS-CoV-2, was shown to be associated with an increased risk of new-onset diabetes. Mechanisms contributing to the development of hyperglycemia are still unclear. We aimed to study whether hyperglycemia is related to insulin resistance and/or beta cell dysfunction.

MATERIALS AND METHODS

Survivors of severe COVID-19 but without a known history of diabetes were examined at baseline (T0) and after 3 (T3) and 6 (T6) months: corticosteroids use, indirect calorimetry, and OGTT. Insulin response and sensitivity (IS) were expressed as insulinogenic (IGI), disposition (DI), and Matsuda insulin sensitivity index (ISI). Resting energy expenditure (REE) and respiratory quotient (RQ) was calculated from the gas exchange and nitrogen losses.

RESULTS

26 patients (out of 37) with complete outcome data were included in the analysis (age ~59.0 years; BMI ~ 30.4, 35% women). Patients were hypermetabolic at T0 (30.3 ± 4.0 kcal/kg lean mass/day, ~120% predicted) but REE declined over 6 months (ΔT6-T0 mean dif. T6-T0 (95% CI): -5.4 (-6.8, -4.1) kcal/kg FFM/day, p < 0.0001). 17 patients at T0 and 13 patients at T6 had hyperglycemia. None of the patients had positive islet autoantibodies. Insulin sensitivity in T0 was similarly low in hyperglycemic (H) and normoglycemic patients (N) (T0 ISI_H = 3.12 ± 1.23, ISI_N = 3.47 ± 1.78, p = 0.44), whereas insulin response was lower in the H group (DI_H = 3.05 ± 1.79 vs DI_N = 8.40 ± 5.42, p = 0.003). Over 6 months ISI (ΔT6-T0 mean dif. T6-T0 for ISI (95% CI): 1.84 (0.45, 3.24), p = 0.01)) increased in the H group only.

CONCLUSIONS

Patients with severe COVID-19 had increased REE and insulin resistance during the acute phase due to the infection and corticosteroid use, but these effects do not persist during the follow-up period. Only patients with insufficient insulin response developed hyperglycemia, indicating that beta cell dysfunction, rather than insulin resistance, was responsible for its occurrence.

Biomarkers of post-match recovery in semi-professional and professional football (soccer)

High-level football (soccer) players face intense physical demands that result in acute and residual fatigue, impairing their physical performance in subsequent matches. Further, top-class players are frequently exposed to match-congested periods where sufficient recovery times are not achievable. To evaluate training and recovery strategies, the monitoring of players' recovery profiles is crucial. Along with performance and neuro-mechanical impairments, match-induced fatigue causes metabolic disturbances denoted by changes in chemical analytes that can be quantified in different body fluids such as blood, saliva, and urine, thus acting as biomarkers. The monitoring of these molecules might supplement performance, neuromuscular and cognitive measurements to guide coaches and trainers during the recovery period. The present narrative review aims to comprehensively review the scientific literature on biomarkers of post-match recovery in semi-professional and professional football players as well as provide an outlook on the role that metabolomic studies might play in this field of research. Overall, no single gold-standard biomarker of match-induced fatigue exists, and a range of metabolites are available to assess different aspects of post-match recovery. The use of biomarker panels might be suitable to simultaneously monitoring these broad physiological processes, yet further research on fluctuations of different analytes throughout post-match recovery is warranted. Although important efforts have been made to address the high interindividual heterogeneity of available markers, limitations inherent to these markers might compromise the information they provide to guide recovery protocols. Further research on metabolomics might benefit from evaluating the long-term recovery period from a high-level football match to shed light upon new biomarkers of post-match recovery.

The Long-Term Efficacy of "Social Buffering" in Artificial Social Agents: Contextual Affective Perception Matters

In dynamic (social) environments, an affective state of "stress" can be adaptive and promote agent wellbeing, but maladaptive if not appropriately regulated. The presence of (and interactions with) affect-based social support has been hypothesised to provide mechanisms to regulate stress (the "social buffering" hypothesis), though the precise, underlying mechanisms are still unclear. However, the hormone oxytocin has been implicated in mediating these effects in at least two ways: by improving social appraisals and reducing the short-term release of stress hormones (i.e., cortisol), and adapting an agent's long-term stress tolerance. These effects likely facilitate an agent's long-term adaptive ability by grounding their physiological and behavioural adaptation in the (affective) social environment, though these effects also appear to be context-dependent. In this paper, we investigate whether two of the hypothesised hormonal mechanisms that underpin the "social buffering" phenomenon affect the long-term wellbeing of (artificial) social agents who share affective social bonds, across numerous social and physical environmental contexts. Building on previous findings, we hypothesise that "social buffering" effects can improve the long-term wellbeing of agents who share affective social bonds in dynamic environments, through regular prosocial interactions with social bond partners. We model some of the effects associated with oxytocin and cortisol that underpin these hypothesised mechanisms in our biologically-inspired, socially-adaptive agent model, and conduct our investigation in a small society of artificial agents whose goal is to survive in challenging environments. Our results find that, while stress can be adaptive and regulated through affective social support, long-term behavioural and physiological adaptation is determined by the contextual perception of affective social bonds, which is influenced by early-stage interactions between affective social bond partners as well as the degree of the physical and social challenges. We also show how these low-level effects associated with oxytocin and cortisol can be used as "biomarkers" of social support and environmental stress. For socially-situated artificial agents, we suggest that these "social buffering" mechanisms can adapt the (adaptive) stress mechanisms, but that the long-term efficacy of this adaptation is related to the temporal dynamics of social interactions and the contextual perception of the affective social and physical environments.

The metabolic stress response: Adaptation to acute-, repeated- and chronic challenges in mice

There is a strong relationship between stress and metabolism. Because acute traumatic- and chronic stress events are often accompanied with metabolic pathophysiology, it is important to understand the details of the metabolic stress response. In this study we directly compared metabolic effects of acute stress with chronic repeated- and chronic unpredictable stress in mouse models. All types of adversities increased energy expenditure, chronic stress exposure decreased body weight gain, locomotor activity and differentially affected fuel utilization. During chronic exposure to variable stressors, carbohydrates were the predominant fuels, whereas fatty acids were catabolized in acutely and repeatedly restrained animals. Chronic exposure to variable stressors in unpredictable manner provoked anxiety. Our data highlight differences in metabolic responses to acute- repeated- and chronic stressors, which might affect coping behavior and underlie stress-induced metabolic and psychopathologies.

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All forms of stress exposure increase energy expenditure and resting metabolic rate

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Increased energy expenditure is fueled in challenge-specific manner

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Acute restraint increases, chronic stress decreases locomotor activity

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Chronic variable stress, but not repeated restraint provokes anxiety/depression

The Role of Vitamin E in Thermal Burn Injuries, Infection, and Sepsis: A Review

Thermal burn injuries are still a serious public health concern in the United States, due to the initial insult and resulting comorbidities. Burned patients are increasingly susceptible to colonization by endogenous and exogenous microorganisms after having lost skin, which acts as the primary protective barrier to environmental contaminants. Furthermore, the onset of additional pathophysiologies, specifically sepsis, becomes more likely in burned patients compared to other injuries. Despite improvements in the early care of burn patients, infections, and sepsis, these pathophysiologies remain major causes of morbidity and mortality and warrant further investigation of potential therapies. Vitamin E may be one such therapy. We aimed to identify publications of studies that evaluated the effectiveness of vitamin E as it pertains to thermal burn injuries, infection, and sepsis. Several investigations ranging from in vitro bench work to clinical studies have examined the impact on, or influence of, vitamin E in vitro, in vivo, and in the clinical setting. To the benefit of subjects it has been shown that enteral or parenteral vitamin E supplementation can prevent, mitigate, and even reverse the effects of thermal burn injuries, infection, and sepsis. Therefore, a large-scale prospective observational study to assess the potential benefits of vitamin E supplementation in patients is warranted and could result in clinical care practice paradigm changes.

Glucocorticoid-Induced Hypokalemic Periodic Paralysis after Short-Term Use of Tenofovir with Hypophosphatemia: A Case Report

Hypokalemic periodic paralysis (HPP) is a neuromuscular disorder associated with muscular dysfunction caused by hypokalemia. There are various causes of HPPs and rarely, HPP appears to be relevant to tenofovir or glucocorticoid treatment. There have been several case reports of tenofovir-related nephrotoxicity or tenofovir-induced HPP. However, a case report of glucocorticoid-induced HPP in a patient using tenofovir temporarily has not been reported. Herein, we report a case of glucocorticoid-induced HPP with short-term use of tenofovir. A 28-year-old man visited the emergency room with decreased muscle power in all extremities (2/5 grade). In their past medical history, the patient was treated with tenofovir for two months for a hepatitis B virus infection. At the time of the visit, the drug had been discontinued for four months. The day before visiting the emergency room, betamethasone was administered at a local clinic for herpes on the lips. Laboratory tests showed hypokalemia, hypophosphatemia, and mild metabolic acidosis. However, urinalysis revealed no abnormal findings. Consequently, it can be postulated that this patient developed HPP by glucocorticoids after taking tenofovir temporarily. This is the first case report of glucocorticoid-induced HPP in a patient using tenofovir. Clinicians who prescribe tenofovir should be aware of HPP occurring when glucocorticoids are used.

The effect of wheat germ-enriched enteral formula on clinical and anthropometric factors in mechanically ventilated patients admitted to the intensive care unit

BACKGROUND & AIMS

Nutritional support is considered as an important therapeutic strategy among critically ill patients. To evaluate the effect of a wheat germ-enriched formula in patients admitted to the intensive care unit (ICU).

METHODS

This randomized controlled clinical trial study was conducted on 100 patients admitted to the ICU. Patients randomly received a wheat germ-enriched formula or a standard formula from the first day of admission until weaning from the ventilator. Then, the duration of mechanical ventilation, the length of ICU, hospital admission, body composition and mortality rate were compared between the two groups.

RESULTS

Based on the results, wheat germ-enriched formula caused a significant reduction in the length of mechanical ventilation (29.80 ± 21.99 days vs. 36.48 ± 8.78 days, P < 0.001), the ICU length of stay (32.92 ± 21.04 days vs. 37.70 ± 8.76, P < 0.001), and the SOFA score (4.60 ± 1.28 vs. 5.68 ± 1.25, P < 0.001) compared to the control group. However, the intervention group demonstrated a significant increase in the basal metabolic rate, mid upper arm circumference, skeletal muscle mass, body cell mass, and GCS score compared to the control group (P < 0.05). Finally, no significant difference was observed between the two groups in terms of the hospital length of stay, ICU mortality, and body fat percentage (P > 0.05).

CONCLUSION

In general, wheat germ enriched formula may exert beneficial effect on clinical and anthropomorphic variables in patients admitted to the ICU.

TRIAL REGISTRATION

The study was approved by the Ethics Committee of the Urmia University of Medical Sciences under number IR.umsu.rec.1396.88 and registered at the Iranian Registry of Clinical Trials Website as IRCT20171221037983N3.

Associations between fecal cortisol and biparental care in a pair-living primate

OBJECTIVES

We quantified variation in fecal cortisol across reproductive periods in Azara's owl monkeys (Aotus azarae) to examine physiological mechanisms that may facilitate biparental care. Specifically, we evaluated evidence for the explanation that owl monkeys have hormonal mechanisms to mobilize energy during periods when each sex is investing heavily in reproduction, that is, the gestation period for females and the infant care period for males.

MATERIALS AND METHODS

Between 2011 and 2015, we monitored 10 groups of Azara's owl monkeys from a wild population in Formosa, Argentina and collected fecal samples from 26 adults (13 males, 13 females). Using enzyme-linked immunosorbent assays, we quantified fecal cortisol as a proxy for evaluating stress responses, including energetic demands, on both sexes during periods of reproduction and parental care.

RESULTS

Male cortisol was lowest during periods when they were caring for young infants (<3 months) compared with periods with older infants or no infant. Female cortisol was elevated during gestation compared with other periods. Mean fecal cortisol in both males and females was lower when an infant was present compared with when females were gestating.

DISCUSSION

Our results do not support the hypothesis that owl monkey males have elevated fecal cortisol during periods when they need to mobilize energy to provide intensive infant care. Our findings are also inconsistent with the Maternal Relief hypothesis. However, results from studies measuring fecal cortisol must be interpreted with care and alternative explanations, such as seasonal fluctuations in diet and thermoenergic demands, should be considered when drawing conclusions.

Glucose Metabolism in Burns-What Happens?

Severe burns represent an important challenge for patients and medical teams. They lead to profound metabolic alterations, trigger a systemic inflammatory response, crush the immune defense, impair the function of the heart, lungs, kidneys, liver, etc. The metabolism is shifted towards a hypermetabolic state, and this situation might persist for years after the burn, having deleterious consequences for the patient's health. Severely burned patients lack energy substrates and react in order to produce and maintain augmented levels of glucose, which is the fuel "ready to use" by cells. In this paper, we discuss biological substances that induce a hyperglycemic response, concur to insulin resistance, and determine cell disturbance after a severe burn. We also focus on the most effective agents that provide pharmacological modulations of the changes in glucose metabolism.

Targeted Metabolomics as a Tool in Discriminating Endocrine From Primary Hypertension

CONTEXT

Identification of patients with endocrine forms of hypertension (EHT) (primary hyperaldosteronism [PA], pheochromocytoma/paraganglioma [PPGL], and Cushing syndrome [CS]) provides the basis to implement individualized therapeutic strategies. Targeted metabolomics (TM) have revealed promising results in profiling cardiovascular diseases and endocrine conditions associated with hypertension.

OBJECTIVE

Use TM to identify distinct metabolic patterns between primary hypertension (PHT) and EHT and test its discriminating ability.

METHODS

Retrospective analyses of PHT and EHT patients from a European multicenter study (ENSAT-HT). TM was performed on stored blood samples using liquid chromatography mass spectrometry. To identify discriminating metabolites a "classical approach" (CA) (performing a series of univariate and multivariate analyses) and a "machine learning approach" (MLA) (using random forest) were used.The study included 282 adult patients (52% female; mean age 49 years) with proven PHT (n = 59) and EHT (n = 223 with 40 CS, 107 PA, and 76 PPGL), respectively.

RESULTS

From 155 metabolites eligible for statistical analyses, 31 were identified discriminating between PHT and EHT using the CA and 27 using the MLA, of which 16 metabolites (C9, C16, C16:1, C18:1, C18:2, arginine, aspartate, glutamate, ornithine, spermidine, lysoPCaC16:0, lysoPCaC20:4, lysoPCaC24:0, PCaeC42:0, SM C18:1, SM C20:2) were found by both approaches. The receiver operating characteristic curve built on the top 15 metabolites from the CA provided an area under the curve (AUC) of 0.86, which was similar to the performance of the 15 metabolites from MLA (AUC 0.83).

CONCLUSION

TM identifies distinct metabolic pattern between PHT and EHT providing promising discriminating performance.

Hypercortisolism and altered glucose homeostasis in obese patients in the pre-bariatric surgery assessment

AIMS

Hypothalamus-pituitary-adrenal (HPA) axis hyperactivity was suggested to be associated with the metabolic syndrome (MS), obesity and diabetes. The aim of this study was to test whether hypercortisolism was associated with altered glucose homeostasis and insulin resistance, hypertension and dyslipidemia in a homogeneous population of obese patients.

MATERIALS/METHODS

In retrospective analysis of a set of data about obese patients attending the outpatient service of a single obesity centre between January 2013 and January 2020, 884 patients with BMI >30 kg/m² were segregated in two subgroups: patients with urinary free cortisol (UFC) higher than normal (UFC+; n = 129) or within the normal range (UFC-; n = 755).

RESULTS

The overall prevalence of UFC+ was 14.6% and double test positivity (morning cortisol >1.8 mcg/dL following overnight dexamethasone suppression test, ODST) was detected in 1.0% of patients. Prediabetes (OR 1.74; 95%CI 1.13-2.69; p = 0.012) and diabetes (OR 2.03; 95%CI 1.21-3.42; p = 0.008) were associated with higher risk of UFC+ when analysis was adjusted for confounding variables. Conversely, hypertension and dyslipidemia were not related to UFC+. Within the individuals with normal FPG and HbA1c, those with higher estimated insulin resistance (HOMA2-IR) maintained a higher risk of UFC+ (OR 2.84, 95%CI 1.06-7.63; p = 0.039) and this relationship was weakened only when the body fat percentage was included into the model.

CONCLUSIONS

In obese patients, hypercortisolism was more frequent across the entire spectrum of altered glucose homeostasis including the very early stages; this relation could not be detected for the other criteria of the MS, as waist, hypertension and atherogenic dyslipidemia.

Acute supplementation with an amino acid mixture suppressed the exercise-induced cortisol response in recreationally active healthy volunteers: a randomized, double-blinded, placebo-controlled crossover study

Background

Few studies have demonstrated the suppressive effects of amino acids (AAs) on the level of cortisol during exercise in humans. We hypothesized that an AA mixture containing arginine, which promotes lipid metabolism, valine, which effectively decreases the level of glucocorticoid, and serine, a substrate in the production of phosphatidylserine that is reported to blunt increases in cortisol, would suppress the exercise-induced cortisol response by combining the positive effects of the AAs synergistically.

Methods

A randomized, double-blinded, placebo-controlled crossover trial was conducted. Twenty healthy recreationally active males ingested either an AA mixture containing 1.8 g of arginine, 1.1 g of valine, and 0.1 g of serine or a placebo. Thirty minutes after ingestion, subjects performed an exercise trial on a cycle ergometer for 80 min at 50% maximal oxygen consumption. Plasma cortisol and other blood parameters immediately before and after the exercise were evaluated.

Results

Plasma cortisol concentrations after exercise were significantly higher than those before exercise in the placebo condition (9.51 ± 0.85 vs 14.39 ± 2.15, p < 0.05), while there was no significant difference in the AA condition (9.71 ± 0.93 vs 9.99 ± 1.23, p = 0.846). In addition, the increase in plasma cortisol before and after exercise was significantly lower in the AA condition than in the placebo condition (0.28 [− 2.75, 3.31] vs 4.87 [0.89, 8.86], p < 0.05). For the level of adrenocorticotropin, there was a significant difference between before and after exercise only in the placebo condition (24.21 ± 2.91 vs 53.17 ± 6.97, p < 0.01) but not in the AA condition (27.33 ± 3.60 vs 46.92 ± 10.41, p = 0.057). Blood glucose, plasma lactate, plasma ammonia, serum creatine phosphokinase, serum total ketone body, and serum free fatty acid were also significantly changed by the exercise load in both conditions, but no significant differences were observed between the two conditions.

Conclusions

The present study demonstrated that the AA mixture suppressed the cortisol response during exercise without affecting exercise-related biological parameters such as glucose or lipid metabolism.

Trial registration

UMIN Clinical Trials Registry, UMIN000023587. Registered 19 August 2016.

Resistance Training in Post-Metabolic and Bariatric Surgery Patients: a Systematic Review

Resistance exercise guidelines exist for obesity but not for post-metabolic and bariatric surgery (MBS) patients. Therefore, the main goal of the present study is to provide evidence to support resistance exercise guidelines for this population. A secondary goal is to evaluate the available evidence to identify gaps for future research. Nine studies evaluating the effect of resistance exercise post-MBS on strength and body composition were included. Resistance training consistently prevented strength loss and when performed by younger population (~ 35 years) also prevented lean mass loss. Combined exercise, but not strength training independently, was found to promote body fat mass loss. Resistance training should be added to post-MBS exercise programs. Sufficiently powered studies using higher volume resistance training with supportive protein consumption and diverse populations are needed.

Glucagon Regulation of Energy Expenditure

Glucagon's ability to increase energy expenditure has been known for more than 60 years, yet the mechanisms underlining glucagon's thermogenic effect still remain largely elusive. Over the last years, significant efforts were directed to unravel the physiological and cellular underpinnings of how glucagon regulates energy expenditure. In this review, we summarize the current knowledge on how glucagon regulates systems metabolism with a special emphasis on its acute and chronic thermogenic effects.

An acute increase in water temperature can increase free amino acid concentrations in the blood, brain, liver, and muscle in goldfish (Carassius auratus)

Water temperature directly affects the body temperature in fish, so increasing water temperatures in oceans and rivers will lead to increases in fish body temperatures. Whilst a range of responses of fish to increases in water temperature have been measured, amino acid metabolism in a fish under high water temperature (HT) conditions has not been investigated. The aim of this study was to determine the effects of an acute increase in water temperature on oxygen consumption, plasma cortisol concentrations, and free amino acid concentrations in plasma and several tissues in goldfish (Carassius auratus). Oxygen consumption and plasma cortisol concentrations were increased in goldfish exposed to HT (30 ± 1 °C) for 200 min compared with goldfish at a control water temperature (CT 17 ± 1 °C). Oxygen consumption and plasma cortisol concentrations in both groups of fish combined were positively correlated. When goldfish were exposed to HT for 300 min oxygen consumption and plasma concentrations of 15 free amino acids were increased compared with goldish at CT. Concentrations of several free amino acids were increased to varying extents in the brain, liver, and muscle tissues. In conclusion, an acute increase in water temperature affected amino acid metabolism differently in the brain, liver, and muscle tissues. Goldfish will be a useful species for further studies of the possible roles of various amino acids in the brain, muscle, and liver during acute increases in water temperature in fish.

Neuroendocrine drivers of risk and resilience: The influence of metabolism & mitochondria

The manifestation of risk versus resilience has been considered from varying perspectives including genetics, epigenetics, early life experiences, and type and intensity of the challenge with which the organism is faced. Although all of these factors are central to determining risk and resilience, the current review focuses on what may be a final common pathway: metabolism. When an organism is faced with a perturbation to the environment, whether internal or external, appropriate energy allocation is essential to resolving the divergence from equilibrium. This review examines the potential role of metabolism in the manifestation of stress-induced neural compromise. In addition, this review details the current state of knowledge on neuroendocrine factors which are poised to set the tone of the metabolic response to a systemic challenge. The goal is to provide an essential framework for understanding stress in a metabolic context and appreciation for key neuroendocrine signals.

Environmentally Induced Epigenetic Plasticity in Development: Epigenetic Toxicity and Epigenetic Adaptation

PURPOSE OF REVIEW

Epigenetic processes represent important mechanisms underlying developmental plasticity in response to environmental exposures. The current review discusses three classes of environmentally-induced epigenetic changes reflecting two aspects of that plasticity, toxicity effects as well as adaptation in the process of development.

RECENT FINDINGS

Due to innate resilience, epigenetic changes caused by environmental exposures may not always lead impairments but may allow the organisms to achieve positive developmental outcomes through appropriate adaptation and a buffering response. Thus, some epigenetic adaptive responses to an immediate stimulus or exposure early in life would be expected to have a survival advantage but these same responses may also result in adverse developmental outcomes as they persists into later life stage. Although accumulating literature has identified environmentally induced epigenetic changes and linked them to health outcomes, we currently face challenges in the interpretation of the functional impact of their epigenetic plasticity.

SUMMARY

Current environmental epigenetic research suggest that epigenetic processes may serve as a mechanism for resilience, and that they can be considered in terms of their impact on toxicity as a negative outcome, but also on adaptation for improved survival or health. This review encourages epigenetic environmental studies to move deeper inside into the functional meaning of epigenetic plasticity in the development.

The effects of daily food ingestion on improved immune functions and health promotion of bodybuilding athletes

The purpose of this study was to investigate the effects of different weight reduction methods on the body composition characteristics, cardiopulmonary functions, and health promotion of elite bodybuilding athletes in a comprehensive manner. For this purpose, the study analyzed the effects of two different weight reduction methods on 25 elite bodybuilding athletes registered at the Bodybuilding Association over a period of 6 weeks. There were interactive effects on macronutrients, macrominerals, and antioxidants according to weight reduction methods as the experiment group (6%±2%) maintained a certain amount of food intakes across various nutrients including energy intakes or made a slow decrease it, whereas the traditional group (16%±4%) made a sharp decrease in it due to relatively greater weight reduction than the experiment group and thus showed pattern differences from it. As for immunity variables, there was an increase to certain cytokines despite the traditional high weight reduction method, but it caused no excessive reduction of immunity or rapid decrease to certain factors of body composition. In addition, there were no significant differences in main and interactive effects on the one-repetition maximum of bench press and squat, which are two functional indicators of health promotion. These findings imply that the low weight reduction method within the range of 6%±2% minimized or maintained changes to muscle circumference or mass while causing no improvement to muscular strength.

Background cortisol versus social anxiety as correlates of HPA-axis recovery from stress in boys with Autism Spectrum Disorder

Children with Autism Spectrum Disorder (ASD) show dysregulation of the expected Hypothalamus-Pituitary-Adrenal (HPA) axis and elevated cortisol responses to stress and response patterns, but little has been reported regarding their recovery from stress in terms of cortisol concentrations. This response was investigated in a sample of 32 young males with ASD aged between 9 and 18 years (M = 14.3 yr, SD = 2.7 yr), using a standardised experimental protocol combined with individualised stressor and non-stressor tasks. Results indicated that about half of the sample demonstrated unexpected HPA axis response patterns, and that recovery from stress cortisol concentrations were significantly associated with a single symptom of Social Phobia and Morning cortisol. These findings suggest that one of the key diagnostic criteria for ASD may be strongly influential in the HPA axis responses of boys with ASD and that training regimesto assist them to form less fearful associations with their non-ASD peers may be central to the academic and social progress of these boys.

Social group dynamics predict stress variability among children in a New Zealand classroom

Previous research proposes stress as a mechanism for linking social environments and biological bodies. In particular, non-human primate studies investigate relationships between cortisol as a measure of stress response and social hierarchies. Because human social structures often include hierarchies of dominance and social status, humans may exhibit similar patterns. Studies of non-human primates, however, have not reached consistent conclusions with respect to relationships between social position and levels of cortisol. While human studies report associations between cortisol and various aspects of social environments, studies that consider social status as a predictor of stress response also report mixed results. Others have argued that perceptions of social status may have different implications for stress response depending upon social context. We propose here that characteristics of children's social networks may be a better predictor of central tendencies and variability of stress response than their perceptions of social status. This is evaluated among 24 children from 9.4 to 11.3 years of age in one upper middle-class New Zealand primary school classroom, assessed through observation within the classroom, self-reports during semi-structured interviews and 221 serial saliva samples provided daily over 10 consecutive school days. A synthetic assessment of the children's networks and peer-relationships was developed prior to saliva-cortisol analysis. We found that greater stability of peer-relationships within groups significantly predicts lower within-group variation in mid-morning cortisol over the two-week period, but not overall within-group differences in mean cortisol.

Adiposity and fat metabolism during combined fasting and lactation in elephant seals

Animals that fast depend on mobilizing lipid stores to power metabolism. Northern elephant seals (Mirounga angustirostris) incorporate extended fasting into several life-history stages: development, molting, breeding and lactation. The physiological processes enabling fasting and lactation are important in the context of the ecology and life history of elephant seals. The rare combination of fasting and lactation depends on the efficient mobilization of lipid from adipose stores and its direction into milk production. The mother elephant seal must ration her finite body stores to power maintenance metabolism, as well as to produce large quantities of lipid and protein-rich milk. Lipid from body stores must first be mobilized; the action of lipolytic enzymes and hormones stimulate the release of fatty acids into the bloodstream. Biochemical processes affect the release of specific fatty acids in a predictable manner, and the pattern of release from lipid stores is closely reflected in the fatty acid content of the milk lipid. The content of the milk may have substantial developmental, thermoregulatory and metabolic consequences for the pup. The lactation and developmental patterns found in elephant seals are similar in some respects to those of other mammals; however, even within the limited number of mammals that simultaneously fast and lactate, there are important differences in the mechanisms that regulate lipid mobilization and milk lipid content. Although ungulates and humans do not fast during lactation, there are interesting comparisons to these groups regarding lipid mobilization and milk lipid content patterns.

Global variation in diurnal cortisol rhythms: evidence from Garisakang forager-horticulturalists of lowland Papua New Guinea

The hypothalamic-pituitary-adrenal (HPA) axis represents an important and evolutionarily ancient biological pathway linking physical and psychological stressors with human health. Despite considerable research exploring the physiological stress response among developed populations, few studies have examined HPA activity in non-industrialized contexts, restricting understanding of variation in human stress reactivity across global socio-ecological diversity. The present study addresses this shortcoming by investigating diurnal cortisol rhythms among Garisakang forager-horticulturalists of remote, lowland Papua New Guinea. Using a large sample of repeated salivary cortisol measurements from 169 participants (age 4-70 years), multilevel growth curve models were constructed to assess Garisakang waking cortisol concentrations and diurnal cortisol slopes. As predicted, results demonstrate identifiable but substantially diminished diurnal cortisol rhythms relative to those of industrialized populations. Sample-wide, Garisakang cortisol concentrations are highest upon waking (mean = 4.86 nmol/L) and decrease throughout the day at a mean rate of only -0.18 nmol/L/h or -6.20%/h. Age and sex significantly predict evaluated cortisol parameters in ways not consistently reported among industrialized populations, suggesting that Garisakang diurnal cortisol rhythms are defined by distinct ontogenetic trajectories across the lifespan. These findings highlight cross-cultural diversity in HPA activity and have important implications for understanding basic mechanisms of the physiological stress response in contexts of chronic physical stressors such as limited nutrition, heavy burden of infectious disease, and high levels of physical activity.

Cyclic bouts of extreme bradycardia counteract the high metabolism of frugivorous bats

Active flight requires the ability to efficiently fuel bursts of costly locomotion while maximizing energy conservation during non-flying times. We took a multi-faceted approach to estimate how fruit-eating bats (Uroderma bilobatum) manage a high-energy lifestyle fueled primarily by fig juice. Miniaturized heart rate telemetry shows that they use a novel, cyclic, bradycardic state that reduces daily energetic expenditure by 10% and counteracts heart rates as high as 900 bpm during flight. Uroderma bilobatum support flight with some of the fastest metabolic incorporation rates and dynamic circulating cortisol in vertebrates. These bats will exchange fat reserves within 24 hr, meaning that they must survive on the food of the day and are at daily risk of starvation. Energetic flexibly in U. bilobatum highlights the fundamental role of ecological pressures on integrative energetic networks and the still poorly understood energetic strategies of animals in the tropics.

To survive, all animals have to balance how much energy they take in and how much they use. They must find enough food to fuel the chemical processes that keep them alive – known as their metabolism – and store leftover fuel to use when food is not available. Bats, for example, have a fast metabolism and powerful flight muscles, which require a lot of energy. Some bat species, such as the tent-making bats, survive on fruit juice, and their food sources are often far apart and difficult to find. These bats are likely to starve if they go without food for more than 24 hours, and therefore need to conserve energy while they are resting.

To deal with potential food shortages, bats and other animals can enter a low-energy resting state called torpor. In this state, animals lower their body temperature and slow down their heart rate and metabolism so that they need less energy to stay alive. However, many animals that live in tropical regions, including tent-making bats, cannot enter a state of torpor, as it is too hot to sufficiently lower their body temperature. Until now, scientists did not fully understand how these bats control how much energy they use.

Now, O’Mara et al. studied tent-making bats in the wild by attaching small heart rate transmitters to four wild bats, and measured their heartbeats over several days. Since each heartbeat delivers oxygen and fuel to the rest of the body, measuring the bats’ heart rate indicates how much energy they are using. The experiments revealed for the first time that tent-making bats periodically lower their heart rates while resting (to around 200 beats per minute). This reduces the amount of energy they use each day by up to 10%, and helps counteract heart rates that can reach 900 beats per minute when the bats are flying.

Overall, these findings show that animals have evolved in various ways to control their use of energy. Future research should use similar technology to continue uncovering how wild animals have adapted to survive in different conditions. This knowledge will help us to understand how life has become so diverse in the tropics and the strategies that animals may use as climates change.

Correlates of whole-blood polyunsaturated fatty acids among young children with moderate acute malnutrition

Background

Severe acute malnutrition (SAM) has been associated with low polyunsaturated fatty acid (PUFA) status. However, investigations regarding PUFA status and correlates in children with moderate acute malnutrition (MAM) from low-income countries are scarce. The aim of this study was to describe whole-blood PUFA levels in children with moderate acute malnutrition (MAM) and to identify correlates of PUFAs.

Methods

We conducted a cross-sectional study using baseline data from a prospective nutritional intervention trial among 1609 children with MAM aged 6–23 months in Burkina Faso,West Africa. Whole-blood PUFAs were measured by gas chromatography and expressed as percent of total whole-blood fatty acids (FA%). Potential correlates of PUFAs including infection, inflammation, hemoglobin, anthropometry (difference between children diagnosed as having MAM based on low mid-upper-arm-circumference (MUAC) only, low MUAC and weight-for-height z-score (WHZ), or low WHZ only) and diet were assessed by linear regression adjusted for age and sex.

Results

Children with MAM had low concentrations of whole-blood PUFAs, particularly n-3 PUFAs. Moreover, children diagnosed with MAM based only on low MUAC had 0.32 (95% confidence interval (CI), 0.14; 0.50) and 0.40 (95% CI, 0.16; 0.63) FA% lower arachidonic acid (AA) than those recruited based on both low WHZ as well as low MUAC and those recruited with low WHZ only, respectively. Infection and inflammation were associated with low levels of all long-chain (LC)-PUFAs, while hemoglobin was positively associated with whole-blood LC-PUFAs.

Conclusion

While PUFA deficiency was not a general problem, overall whole-blood PUFA concentrations, especially of n-3 PUFAs, were low. Infection, inflammation, hemoglobin, anthropometry and diet were correlates of PUFAs concentrations in children with MAM.

Trial registration

The trial is registered at http://www.isrctn.com (ISRCTN42569496).

A randomized cross-over study of the acute effects of running 5 km on glucose, insulin, metabolic rate, cortisol and Troponin T

Background

We aimed to study the impact by running 5 km, at maximal speed, on the normal variations of metabolic variables related to glucose, insulin, insulin sensitivity, cortisol, glucagon, Troponin T and metabolic rate.

Material and methods

Five women and 12 men 25.7±5.2 years of age with a body-mass-index of 22.5±2.3 kg/m² where recruited to run 5 km at individual maximal speed in the morning, and to a corresponding day of rest, followed by standardized breakfast and lunch meals. Blood sampling and measurement of indirect calorimetry were done before and after meals. The participants were randomized regarding the order of the two trial-days in this cross-over study.

Results

Insulin and cortisol levels were higher, and insulin sensitivity was lower, on the race-day compared with the day of rest (linear mixed model: p<0.0001 for all three analyses). However, glucose levels and metabolic rate did not differ between the two trial days (p = 0.29 and p = 0.53, respectively). When analyzing specific time-points we found that glucose increased from 5.01±0.37 mmol/l to 6.36 ± 1.3 mmol/l, p<0.0001, by running, while serum insulin concomitantly increased from 42±21 to 90±54 pmol/l, p<0.0001. In accordance, the QUICKI index of serum sensitivity, 1/(log₁₀insulin+log₁₀glucose), was lowered post-race, p<0.0001. Serum cortisol levels increased from 408±137 nmol/l to 644±171 nmol/l, p<0.0001, post-race while serum glucagon levels were unaffected. Troponin T was detectable in serum post-race in 12 out of the 17 participants and reached or surpassed the clinical reference level of 15 ng/l in three subjects. Post-race electrocardiograms displayed no pathologies.

Conclusions

Relatively short running-races can apparently induce a reduction in insulin sensitivity that is not fully compensated by concomitantly increased insulin secretion intended to ensure euglycemia. Since also Troponin T was detected in plasma in a majority of the participants, our data suggest that it is possible to induce considerable metabolic stress by running merely 5 km, when striving for maximal speed.

Systems characterization of differential plasma metabolome perturbations following thrombotic and non-thrombotic myocardial infarction

Myocardial infarction (MI) is an acute event characterized by myocardial necrosis. Thrombotic MI is caused by spontaneous atherosclerotic plaque disruption that results in a coronary thrombus; non-thrombotic MI occurs secondary to oxygen supply-demand mismatch. We sought to characterize the differential metabolic perturbations associated with these subtypes utilizing a systems approach. Subjects presenting with thrombotic MI, non-thrombotic MI and stable coronary artery disease (CAD) were included. Whole blood was collected at two acute time-points and at a time-point representing the quiescent stable disease state. Plasma metabolites were analyzed by untargeted UPLC-MS/MS and GC-MS. A weighted network was constructed, and modules were determined from the resulting topology. To determine perturbed modules, an enrichment analysis for metabolites that demonstrated between-group differences in temporal change across the disease state transition was then conducted.

BIOLOGICAL SIGNIFICANCE

We report evidence of metabolic perturbations of acute MI and determine perturbations specific to thrombotic MI. Specifically, a module characterized by elevated glucocorticoid steroid metabolites following acute MI showed greatest perturbation following thrombotic MI. Modules characterized by elevated pregnenolone metabolites, monoacylglycerols, and acylcarnitines were perturbed following acute MI. A module characterized by a decrease in plasma amino acids following thrombotic MI was differentially perturbed between MI subtypes.

Whole-Body Protein Metabolism in Chronic Heart Failure: Relationship to Anabolic and Catabolic Hormones

BACKGROUND

Patients with chronic heart failure frequently experience profound wasting during the course of the disease, a condition termed cardiac cachexia. Although protein is the primary structural and functional component of most tissues, few studies have examined the effect of heart failure on protein metabolism. Moreover, no study has assessed the relationship of protein turnover to hormonal alterations thought to promote cachexia. Thus, our goal was to determine if whole-body protein metabolism is altered in heart failure patients and to assess the relationship of protein kinetics to circulating levels of anabolic and catabolic hormones.

METHODS

We measured whole-body protein metabolism using 13C-leucine, body composition, and circulating anabolic and catabolic hormone levels in 10 patients with chronic heart failure and 11 elderly controls.

RESULTS

No differences in leucine rate of appearance, oxidation, or nonoxidative disposal were noted between heart failure patients and controls. However, in a subgroup of patients characterized by increased resting energy expenditure for their metabolic body size (n = 4; > or = 20% above that predicted from fat-free mass), leucine rate of appearance (mean +/- SE; 146 +/- 6 micromol/min), an index of protein breakdown, tended to be higher compared with patients with normal resting energy expenditure (n = 5; 120 +/- 8 micromol/min) and controls (127 +/- 4 micromol/min; p = .06). Alterations in anabolic/catabolic hormone balance did not explain increased protein breakdown in this subgroup, and no correlations were found between hormone levels and protein breakdown in the heart failure group as a whole. In contrast, increased circulating interleukin-6 soluble receptor (r = 0.829; p < .01) and reduced insulin-like growth factor-I (r =-.751; p < .05) levels were related to greater rates of leucine oxidation in heart failure patients.

CONCLUSION

Our results demonstrate that, although increased protein turnover is not a generalized feature of heart failure, there is a subgroup of patients characterized by resting hypermetabolism and increased protein breakdown. Moreover, hormonal alterations related to the heart failure syndrome were related to increased protein oxidation.

Probiotic With or Without Fiber Controls Body Fat Mass, Associated With Serum Zonulin, in Overweight and Obese Adults-Randomized Controlled Trial

Background

The gut microbiota is interlinked with obesity, but direct evidence of effects of its modulation on body fat mass is still scarce. We investigated the possible effects of Bifidobacterium animalisssp. lactis 420 (B420) and the dietary fiber Litesse® Ultra polydextrose (LU) on body fat mass and other obesity-related parameters.

Methods

225 healthy volunteers (healthy, BMI 28–34.9) were randomized into four groups (1:1:1:1), using a computer-generated sequence, for 6 months of double-blind, parallel treatment: 1) Placebo, microcrystalline cellulose, 12 g/d; 2) LU, 12 g/d; 3) B420, 10¹⁰ CFU/d in microcrystalline cellulose, 12 g/d; 4) LU + B420, 12 g + 10¹⁰ CFU/d. Body composition was monitored with dual-energy X-ray absorptiometry, and the primary outcome was relative change in body fat mass, comparing treatment groups to Placebo. Other outcomes included anthropometric measurements, food intake and blood and fecal biomarkers. The study was registered in Clinicaltrials.gov (NCT01978691).

Findings

There were marked differences in the results of the Intention-To-Treat (ITT; n = 209) and Per Protocol (PP; n = 134) study populations. The PP analysis included only those participants who completed the intervention with > 80% product compliance and no antibiotic use. In addition, three participants were excluded from DXA analyses for PP due to a long delay between the end of intervention and the last DXA measurement. There were no significant differences between groups in body fat mass in the ITT population. However, LU + B420 and B420 seemed to improve weight management in the PP population. For relative change in body fat mass, LU + B420 showed a − 4.5% (− 1.4 kg, P = 0.02, N = 37) difference to the Placebo group, whereas LU (+ 0.3%, P = 1.00, N = 35) and B420 (− 3.0%, P = 0.28, N = 24) alone had no effect (overall ANOVA P = 0.095, Placebo N = 35). A post-hoc factorial analysis was significant for B420 (− 4.0%, P = 0.002 vs. Placebo). Changes in fat mass were most pronounced in the abdominal region, and were reflected by similar changes in waist circumference. B420 and LU + B420 also significantly reduced energy intake compared to Placebo. Changes in blood zonulin levels and hsCRP were associated with corresponding changes in trunk fat mass in the LU + B420 group and in the overall population. There were no differences between groups in the incidence of adverse events.

Discussion

This clinical trial demonstrates that a probiotic product with or without dietary fiber controls body fat mass. B420 and LU + B420 also reduced waist circumference and food intake, whereas LU alone had no effect on the measured outcomes.

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The probiotic B420 and synbiotic LU + B420 seem to control body fat mass in humans, especially in the abdominal area.

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B420 and LU + B420 reduce waist circumference and energy intake, but only LU + B420 increases lean body mass.

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Reduced body fat is associated with zonulin, a marker of epithelial permeability, supporting earlier preclinical findings.

Concise results on probiotics for weight management are lacking. Stenman et al. show in a gold standard clinical study that the probiotic B420 with or without a fiber controls body fat, waist circumference and energy intake when taken in a dietary intervention of six months. Study participants maintained habitual diet and physical activity. Stenman et al. link the benefit to changes in serum zonulin, a potential gut permeability marker. The authors have previously shown in animal studies that these gut microbiota targeting products improve metabolic health in mice by strengthening gut barrier function. These effects are now translated to humans.

The food-insecurity obesity paradox: A resource scarcity hypothesis

Food insecurity is paradoxically associated with obesity in the United States. Current hypotheses to explain this phenomenon are descriptive regarding the low food security population's dietary and physical activity habits, but are not mechanistic. Herein it is proposed that a resource scarcity hypothesis may explain this paradox, such that fattening is a physiologically regulated response to threatened food supply that occurs specifically in low social status individuals. Evidence that this may be occurring, the implications for addressing the food insecurity-obesity paradox, and future areas of research, are reviewed and discussed.

The demands of lactation promote differential regulation of lipid stores in fasting elephant seals

Fasting animals must ration stored reserves appropriately for metabolic demands. Animals that experience fasting concomitant with other metabolically demanding activities are presented with conflicting demands of energy conservation and expenditure. Our objective was to understand how fasting northern elephant seals regulate the mobilization of lipid reserves and subsequently milk lipid content during lactation. We sampled 36 females early and 39 at the end of lactation. To determine the separate influences of lactation from fasting, we also sampled fasting but non-lactating females early and late (8 and 6 seals, respectively) in their molting fasting period. Mass and adiposity were measured, as well as circulating non-esterified fatty acid (NEFA), triacylglycerol (TAG), cortisol, insulin and growth hormone levels. Milk was collected from lactating females. Milk lipid content increased from 31% in early to 51% in late lactation. In lactating females plasma NEFA was positively related to cortisol and negatively related to insulin, but in molting seals, only variation in cortisol was related to NEFA. Milk lipid content varied with mass, adiposity, NEFA, TAG, cortisol and insulin. Surprisingly, growth hormone concentration was not related to lipid metabolites or milk lipid. Suppression of insulin release appears to be the differential regulator of lipolysis in lactating versus molting seals, facilitating mobilization of stored lipids and maintenance of high NEFA concentrations for milk synthesis. Milk lipid was strongly impacted by the supply of substrate to the mammary gland, indicating regulation at the level of mobilization of lipid reserves.

Anxiety Symptoms During Adolescence Predicts Salivary Cortisol in Early Adulthood Among Blacks; Sex differences

BACKGROUND

Although the link between psychological distress and altered cortisol level has been already shown; very limited information exists about this association among Black youth.

OBJECTIVES

We tested sex differences in predictive role of symptoms of anxiety during adolescence on annual decline in morning salivary cortisol levels in early adulthood among Black youth.

PATIENTS AND METHODS

Data came from wave 1 (year 1994), wave 6 (year 2000), and wave 7 (year 2001) of the Flint adolescent study. In this study 176 Black youth (85 males and 91 females) were followed for 7 years from mean age of 15 at baseline to 22 at the end of follow up. Linear regression was used for data analysis with change in salivary cortisol from 2000 to 2001 as the dependent variable, symptoms of anxiety, at 1994 as independent variable, age, number of employed parents, depressive symptoms and alcohol use at 1994 as controls, and sex as the moderator.

RESULTS

Higher level of anxiety symptoms at 1994 was predictive of a higher decline in morning salivary cortisol from 2000 to 2001 for all youths, while the effects of baseline socio-economics, depressive symptoms, and alcohol use were controlled. Among female participants, anxiety symptoms at 1994 were predictive of a greater decline in morning salivary cortisol level from 2000 to 2001. The association was not found among males.

CONCLUSIONS

Our findings suggest sex differences in the predictive role of anxiety symptoms during adolescence on the annual decline in cortisol level during early adulthood. While most research on this topic is among White middle class individuals, our findings shed more light on the longitudinal links between psychological distress and the hypothalamus-pituitary-adrenal (HPA) axis function among Black youth.

Impact of circadian misalignment on energy metabolism during simulated nightshift work

Eating at a time when the internal circadian clock promotes sleep is a novel risk factor for weight gain and obesity, yet little is known about mechanisms by which circadian misalignment leads to metabolic dysregulation in humans. We studied 14 adults in a 6-d inpatient simulated shiftwork protocol and quantified changes in energy expenditure, macronutrient utilization, appetitive hormones, sleep, and circadian phase during day versus nightshift work. We found that total daily energy expenditure increased by ∼4% on the transition day to the first nightshift, which consisted of an afternoon nap and extended wakefulness, whereas total daily energy expenditure decreased by ∼3% on each of the second and third nightshift days, which consisted of daytime sleep followed by afternoon and nighttime wakefulness. Contrary to expectations, energy expenditure decreased by ∼12-16% during scheduled daytime sleep opportunities despite disturbed sleep. The thermic effect of feeding also decreased in response to a late dinner on the first nightshift. Total daily fat utilization increased on the first and second nightshift days, contrary to expectations, and carbohydrate and protein utilization were reduced on the second nightshift day. Ratings of hunger were decreased during nightshift days despite decreases in 24-h levels of the satiety hormones leptin and peptide-YY. Findings suggest that reduced total daily energy expenditure during nightshift schedules and reduced energy expenditure in response to dinner represent contributing mechanisms by which humans working and eating during the biological night, when the circadian clock is promoting sleep, may increase the risk of weight gain and obesity.

Metabolic responses to adrenocorticotropic hormone (ACTH) vary with life-history stage in adult male northern elephant seals

Strong individual and life-history variation in serum glucocorticoids has been documented in many wildlife species. Less is known about variation in hypothalamic-pituitary-adrenal (HPA) axis responsiveness and its impact on metabolism. We challenged 18 free-ranging adult male northern elephant seals (NES) with an intramuscular injection of slow-release adrenocorticotropic hormone (ACTH) over 3 sample periods: early in the breeding season, after 70+ days of the breeding fast, and during peak molt. Subjects were blood sampled every 30 min for 2h post-injection. Breeding animals were recaptured and sampled at 48 h. In response to the ACTH injection, cortisol increased 4-6-fold in all groups, and remained elevated at 48 h in early breeding subjects. ACTH was a strong secretagogue for aldosterone, causing a 3-8-fold increase in concentration. Cortisol and aldosterone responses did not vary between groups but were correlated within individuals. The ACTH challenge produced elevations in plasma glucose during late breeding and molting, suppressed testosterone and thyroid hormone at 48 h in early breeding, and increased plasma non-esterified fatty acids and ketoacids during molting. These data suggest that sensitivity of the HPA axis is maintained but the metabolic impacts of cortisol and feedback inhibition of the axis vary with life history stage. Strong impacts on testosterone and thyroid hormone suggest the importance of maintaining low cortisol levels during the breeding fast. These data suggest that metabolic adaptations to extended fasting in NES include alterations in tissue responses to hormones that mitigate deleterious impacts of acute or moderately sustained stress responses.

The effect of ketoconazole on post-burn inflammation, hypermetabolism and clinical outcomes

Background

Hypercortisolemia has been suggested as a primary hormonal mediator of whole-body catabolism following severe burn injury. Ketoconazole, an anti-fungal agent, inhibits cortisol synthesis. We, therefore, studied the effect of ketoconazole on post-burn cortisol levels and the hyper-catabolic response in a prospective randomized trial (block randomization 2∶1).

Methodology/Principal Findings

Fifty-five severely burned pediatric patients with >30% total body surface area (TBSA) burns were enrolled in this trial. Patients were randomized to receive standard care plus either placebo (controls, n = 38) or ketoconazole (n = 23). Demographics, clinical data, serum hormone levels, serum cytokine expression profiles, organ function, hypermetabolism measures, muscle protein synthesis, incidence of wound infection sepsis, and body composition were obtained throughout the acute hospital course. Statistical analysis was performed using Fisher’s exact test, Student’s t-test, and parametric and non-parametric two-way repeated measures analysis of variance where applicable. Patients were similar in demographics, age, and TBSA burned. Ketoconazole effectively blocked cortisol production, as indicated by normalization of the 8-fold elevation in urine cortisol levels [F(1, 376) = 85.34, p<.001] with the initiation of treatment. However, there were no significant differences in the inflammatory response, acute-phase proteins, body composition, muscle protein breakdown or synthesis, or organ function between groups.

Conclusions

Both groups were markedly hypermetabolic and catabolic throughout the acute hospital stay. Normalization of hypercortisolemia with ketoconazole therapy had no effect on whole-body catabolism or the post-burn inflammatory or hypermetabolic response, suggesting that hypercortisolemia does not play a central role in the post-burn hypermetabolic catabolic response.

Trial Registration

ClinicalTrials.gov NCT00675714; and NCT00673309

Effects of supplemental fish oil on resting metabolic rate, body composition, and salivary cortisol in healthy adults

Background

To determine the effects of supplemental fish oil (FO) on resting metabolic rate (RMR), body composition, and cortisol production in healthy adults.

Methods

A total of 44 men and women (34 ± 13y, mean+SD) participated in the study. All testing was performed first thing in the morning following an overnight fast. Baseline measurements of RMR were measured using indirect calorimetry using a facemask, and body composition was measured using air displacement plethysmography. Saliva was collected via passive drool and analyzed for cortisol concentration using ELISA. Following baseline testing, subjects were randomly assigned in a double blind manner to one of two groups: 4 g/d of Safflower Oil (SO); or 4 g/d of FO supplying 1,600 mg/d eicosapentaenoic acid (EPA) and 800 mg/d docosahexaenoic acid (DHA). All tests were repeated following 6 wk of treatment. Pre to post differences were analyzed using a treatment X time repeated measures ANOVA, and correlations were analyzed using Pearson's r.

Results

Compared to the SO group, there was a significant increase in fat free mass following treatment with FO (FO = +0.5 ± 0.5 kg, SO = -0.1 ± 1.2 kg, p = 0.03), a significant reduction in fat mass (FO = -0.5 ± 1.3 kg, SO = +0.2 ± 1.2 kg, p = 0.04), and a tendency for a decrease in body fat percentage (FO = -0.4 ± 1.3% body fat, SO = +0. 3 ± 1.5% body fat, p = 0.08). No significant differences were observed for body mass (FO = 0.0 ± 0.9 kg, SO = +0.2 ± 0.8 kg), RMR (FO = +17 ± 260 kcal, SO = -62 ± 184 kcal) or respiratory exchange ratio (FO = -0.02 ± 0.09, SO = +0.02 ± 0.05). There was a tendency for salivary cortisol to decrease in the FO group (FO = -0.064 ± 0.142 μg/dL, SO = +0.016 ± 0.272 μg/dL, p = 0.11). There was a significant correlation in the FO group between change in cortisol and change in fat free mass (r = -0.504, p = 0.02) and fat mass (r = 0.661, p = 0.001).

Conclusion

6 wk of supplementation with FO significantly increased lean mass and decreased fat mass. These changes were significantly correlated with a reduction in salivary cortisol following FO treatment.

Acute effects of bright light exposure on cortisol levels

Multisynaptic neural and endocrine pathways from the suprachiasmatic nucleus of the hypothalamus have been hypothesized to communicate circadian and photic information to the adrenal glands. In humans, light exposure has been reported to have no effect, increase, or decrease cortisol levels. These inconsistent findings in humans may be related to differences among studies including the intensity (approximately 500 to 5500 lux), duration (15 min to 4 h), and circadian phase of light exposure. The authors assessed the influence of exposure to bright light on cortisol levels in humans during the rising and descending phases of the circadian rhythm of cortisol, that is, when cortisol levels are high. Twenty healthy men and women were studied using a within-subject research design. Subjects were studied in an environment free of time cues for 9 to 10 days. Subjects received a 6.7-h exposure of bright light (approximately 10,000 lux; equivalent to ambient light intensity just after sunrise or just before sunset) or dim light (approximately 3 lux; equivalent to candle light) during the biological night and morning. Bright light exposure significantly reduced plasma cortisol levels at both circadian phases studied, whereas dim light exposure had little effect on cortisol levels. The finding of an acute suppressive effect of bright light exposure on cortisol levels supports the existence of a mechanism by which photic information can acutely influence the human adrenal glands.

Short-term prednisone use antagonizes insulin's anabolic effect on muscle protein and glucose metabolism in young healthy people

Glucocorticoids cause muscle atrophy and weakness, but the mechanisms for these effects are unclear. The purpose of this study was to test a hypothesis that prednisone (Pred) counteracts insulin's anabolic effects on muscle. A randomized, double-blind cross-over design was used to test the effects of 6 days either Pred (0.8 mg x kg(-1) x day(-1)) or placebo use in seven healthy young volunteers. Protein dynamics were measured across the leg using stable isotope tracers of leucine (Leu) and phenylalanine (Phe) after overnight fast and during a hyperinsulinemic (1.5 microU x min(-1) x kg FFM(-1)) euglycemic clamp with amino acid replacement. Fasting glucose, amino acids, insulin, and glucagon were higher (P < 0.01) on Pred vs. placebo, whereas leg blood flow was 18% lower. However, basal whole body and leg kinetics of Leu and Phe were unaltered by Pred. Insulin infusion increased leg glucose uptake in both trials but was 65% lower with Pred than with placebo. Insulin in both trials similarly suppressed whole body flux of Leu and Phe. Importantly, insulin increased net Leu and Phe balance across the leg and the balance between muscle protein synthesis and breakdown, but these changes were 45-140% lower (P < 0.03) in Pred than in placebo. The present study demonstrates that short-term Pred use in healthy people does not alter whole body or leg muscle protein metabolism during the postaborptive state but causes muscle insulin resistance for both glucose and amino acid metabolism, with a blunted protein anabolism. This interactive effect may lead to muscle atrophy with continued use of glucocorticoids.