Diurnal Variation of Hormonal and Lipid Biomarkers in a Molecular Epidemiology-Like Setting

Impact of the menstrual cycle phases and time of day on markers of stress: salivary α-amylase and secretory immunoglobulin A

Previous reports suggest that the menstrual cycle (MC) phases can impact cortisol concentrations. However, research is needed on whether the MC impacts other markers of stress and immune function. It has also been shown that some biomarkers are impacted by time of day, although differences between morning (AM) and afternoon (PM) biomarkers have not been studied over the course of the MC. This study assessed the effect of MC phases and time of day on salivary stress biomarkers [salivary α-amylase (sAA), secretory immunoglobulin A (SIgA)], progesterone, resting blood pressure and resting heart rate (RHR). A single-group repeated measure design was employed in which seventeen participants (n = 17) monitored their MC for two months while attending eight experimental sessions which included both AM and PM sessions during each predicted 1) menses, 2) follicular, 3) ovulatory and 4) luteal phases. Resting blood pressures, heart rates, body composition parameters (assessed via bioelectrical impedance analysis), sAA and SIgA concentrations were assessed. No time of day x MC phase interactions (p > 0.05) were noted for sAA or SIgA, resting blood pressure, heart rate, or body composition parameters. However, sAA and RHR were significantly higher in the PM, while SIgA was significantly higher in the AM. These data suggest that the MC phases do not impact sAA or SIgA, resting blood pressure, heart rates, or body composition parameters. However, time-of-day impacts RHR and concentrations of sAA and SIgA. These findings provide implications for female participants in research dealing with these biomarkers.

Advancing Chrononutrition for Cardiometabolic Health: A 2023 National Heart, Lung, and Blood Institute Workshop Report

The circadian system maintains optimal biological functions at the appropriate time of day, and the disruption of this organization can contribute to the pathogenesis of cardiometabolic disorders. The timing of eating is a prominent external time cue that influences the circadian system. "Chrononutrition" is an emerging dimension of nutrition and active area of research that examines how timing-related aspects of eating and nutrition impact circadian rhythms, biological processes, and disease pathogenesis. There is evidence to support chrononutrition as a form of chronotherapy, such that optimizing the timing of eating may serve as an actionable strategy to improve cardiometabolic health. This report summarizes key information from the National Heart, Lung, and Blood Institute's virtual workshop entitled "Chrononutrition: Elucidating the Role of Circadian Biology and Meal Timing in Cardiometabolic Health," which convened on May 2 to 3, 2023, to review current literature and identify critical knowledge gaps and research opportunities. The speakers presented evidence highlighting the impact on cardiometabolic health of earlier and shorter eating windows and more consistent day-to-day eating patterns. The multidimensionality of chrononutrition was a common theme, as it encompasses multiple facets of eating along with the timing of other behaviors including sleep and physical activity. Advancing the emerging field of chrononutrition will require: (1) standardization of terminology and metrics; (2) scalable and precise tools for real-world settings; (3) consideration of individual differences that may act as effect modifiers; and (4) deeper understanding of social, behavioral, and cultural influences. Ultimately, there is great potential for circadian-based dietary interventions to improve cardiometabolic health.

Association of Insomnia, Lipid Profile, and Lipid-Lowering Medications: A Narrative Review

Sleep is a fundamental phenomenon that helps maintain normal physiological processes. Conversely, sleep disorders, usually presented as insomnia, are a common public health problem that can lead to multiple pathophysiological changes in humans, including lipid metabolic abnormality. Interestingly, several previous studies have examined the potential relation of insomnia to metabolic syndrome and hyperlipidemia and found that insomnia was associated with elevated plasma cholesterol and triglyceride concentrations. This review summarizes evidence regarding the linkage between insomnia and lipid abnormalities. Moreover, the underlying physiologic mechanisms linking insomnia to lipid abnormalities are systemically discussed. Finally, issues with lipid-lowering drugs and the risk of insomnia are also presented. This knowledge can improve our understanding of the pathophysiological features of insomnia, which may help to prevent and treat insomnia-induced dyslipidemia clinically.

Biospecimens in the HEALthy Brain and Child Development (HBCD) Study: Rationale and protocol

The HEALthy Brain and Child Development (HBCD) Study, a multi-site prospective longitudinal cohort study, will examine human brain, cognitive, behavioral, social, and emotional development beginning prenatally and planned through early childhood. The longitudinal collection of biological samples from over 7000 birthing parents and their children within the HBCD study enables research on pre- and postnatal exposures (e.g., substance use, toxicants, nutrition), and biological processes (e.g., genetics, epigenetic signatures, proteins, metabolites) on neurobehavioral developmental outcomes. The following biosamples are collected from the birthing parent: 1) blood (i.e., whole blood, serum, plasma, buffy coat, and dried blood spots) during pregnancy, 2) nail clippings during pregnancy and one month postpartum, 3) urine during pregnancy, and 4) saliva during pregnancy and at in-person postnatal assessments. The following samples are collected from the child at in-person study assessments: 1) saliva, 2) stool, and 3) urine. Additionally, placenta tissue, cord blood, and cord tissue are collected by a subset of HBCD sites. Here, we describe the rationale for the collection of these biospecimens, their current and potential future uses, the collection protocol, and collection success rates during piloting. This information will assist research teams in the planning of future studies utilizing this collection of biological samples.

DNAJC12 Deficiency, an Emerging Condition Picked Up by Newborn Screening: A Case Illustration and a Novel Variant Identified

DNAJC12 deficiency is a recently described inherited metabolic disorder resulting in hyperphenylalaninemia and neurotransmitter deficiency. The effect of treatment on the prevention of neurological manifestations in this newly reported and heterogenous disorder is not fully understood, and the optimal treatment strategy remains to be elucidated. The global or regional incidence of the disease is yet to be estimated. Here, we report the first individual diagnosed with DNAJC12 deficiency in Hong Kong; the condition was picked up by newborn screening due to hyperphenylalaninemia after ruling out phenylalanine hydroxylase deficiency and other tetrahydrobiopterin related disorders. Compound heterozygous variants in the DNAJC12 gene were identified, which included a novel missense change and a nonsense pathogenic variant. Treatment with neurotransmitter precursors (tetrahydrobiopterin, levodopa, and oxitriptan) was initiated at four months of age, and dietary protein restriction was started at four years and six months of age. He remains asymptomatic at four and a half years of age, apart from having mildly impaired socio-communication and language development. In this report, we discuss the current diagnostic approach to hyperphenylalaninemia in newborn screening and the uncertainties that exist in the clinical outcome from earlier detection, treatment, and monitoring of DNAJC12-deficiency patients.

The relationship between oxidative balance score and circadian syndrome: evidence from the NHANES 2005-2018

Background

The oxidative balance score (OBS) is a composite indicator that evaluates the balance between pro-oxidants and antioxidants in one's diet and lifestyle. However, the relationship between OBS and circadian syndrome (CircS) has remained unexplored. This investigation aimed to determine a correlation between OBS and CircS.

Methods

This population-based study examined 7,202 participants from the 2005 to 2018 National Health and Nutrition Examination Survey (NHANES), 1,433 of whom had CircS. We utilized weighted multivariate logistic regression, trend tests, subgroup analysis, and interaction tests to evaluate the correlation between OBS (total OBS, dietary OBS, and lifestyle OBS) and CircS. Restricted cubic splines (RCS) models and threshold effect analysis were used to explore nonlinear relationships.

Results

Multivariate logistic regression analysis indicated that the protective factor for CircS was a high OBS level (total OBS: Odds ratio (OR) = 0.95, 95% Confidence interval (CI): 0.93-0.97; dietary OBS: OR = 0.98, 95% CI: 0.96-1.00; lifestyle OBS: OR = 0.65, 95% CI: 0.61-0.69). Compared to the quartile 1 group, OBS (total OBS, dietary OBS, and lifestyle OBS) was negatively and statistically significantly associated with the risk of developing Circs in the quartile 4 group (total OBS: OR = 0.47, 95% CI: 0.32-0.70; dietary OBS: OR = 0.69, 95% CI: 0.48-0.99; lifestyle OBS: OR = 0.07, 95% CI: 0.04-0.11). According to subgroup analysis and interaction tests, there was an interaction effect between the association of lifestyle OBS and CircS in terms of education level (p for interaction = 0.01). Furthermore, we observed a nonlinear negative relationship between lifestyle OBS and CircS prevalence, with inflection points at 6 (p for nonlinearity = 0.002).

Conclusion

The results showed a substantial negative connection between OBS and CircS. Encouraging foods filled with antioxidants and antioxidant-rich lifestyles may reduce the risk of CircS.

Female rodents in behavioral neuroscience: Narrative review on the methodological pitfalls

Since the NIH 'Sex as biological variable' policy, the percentage of studies including female subjects have increased largely. Nonetheless, many researchers fail to adequate their protocols to include females. In this narrative review, we aim to discuss the methodological pitfalls of the inclusion of female rodents in behavioral neuroscience. We address three points to consider in studies: the manipulations conducted only in female animals (such as estrous cycle monitoring, ovariectomy, and hormone replacement), the consideration of males as the standard, and biases related to interpretation and publication of the results. In addition, we suggest guidelines and perspectives for the inclusion of females in preclinical research.

Male Body Odor Affects Emotional State, LH, and Cortisol Secretion in Women of Different Age Groups

Hormone changes across women's menstrual cycles may lead to changes in their perceptions of chemical signals and their hormonal responses to these cues. The aim of the present study was to determine the role of menstrual cycle phase in the response to extracts of male axillary secretions (EMAS) in women. We tested healthy reproductive age and premenopausal women (n = 29). An EMAS/control solution was applied once every two hours during either the follicular or luteal phase, at which point saliva samples for luteinizing hormone (LH) and cortisol monitoring were collected. LH and cortisol concentrations were analyzed using the enzyme immunoassay (EIA) technique. Positive and Negative Affect Schedule (PANAS) and Visual Analogue Scales (VAS) scores were used to assess the participants' moods. For the first time, we showed that EMAS may produce opposite effects on LH secretion depending on the menstrual cycle phase of the recipient. We observed a significant increase in the number of LH peaks (p = 0.0447) and their amplitudes (p = 0.0469) when EMAS was applied during the follicular phase, while the same application in the luteal phase lowered the amplitudes of LH peaks (p = 0.0382). For the first time, we showed that EMAS application increased salivary cortisol levels in reproductive age women relative to premenopausal women (p = 0.0032). PANAS scores revealed changes in positive and negative affect after EMAS application. Our data indicate the significance of the menstrual cycle phase for EMAS' effects on LH secretion and mood, but not on cortisol secretion in women.

Quantifying the variability in the assessment of reproductive hormone levels

OBJECTIVE

To quantify how representative a single measure of reproductive hormone level is of the daily hormonal profile using data from detailed hormonal sampling in the saline placebo-treated arm conducted over several hours.

DESIGN

Retrospective analysis of data from previous interventional research studies evaluating reproductive hormones.

SETTING

Clinical Research Facility at a tertiary reproductive endocrinology centre at Imperial College Hospital NHS Foundation Trust.

PATIENTS

Overall, 266 individuals, including healthy men and women (n = 142) and those with reproductive disorders and states (n = 124 [11 with functional hypothalamic amenorrhoea, 6 with polycystic ovary syndrome, 62 women and 32 men with hypoactive sexual desire disorder, and 13 postmenopausal women]), were included in the analysis.

INTERVENTIONS

Data from 266 individuals who had undergone detailed hormonal sampling in the saline placebo-treated arms of previous research studies was used to quantify the variability in reproductive hormones because of pulsatile secretion, diurnal variation, and feeding using coefficient of variation (CV) and entropy.

MAIN OUTCOME MEASURES

The ability of a single measure of reproductive hormone level to quantify the variability in reproductive hormone levels because of pulsatile secretion, diurnal variation, and nutrient intake.

RESULTS

The initial morning value of reproductive hormone levels was typically higher than the mean value throughout the day (percentage decrease from initial morning measure to daily mean: luteinizing hormone level 18.4%, follicle-stimulating hormone level 9.7%, testosterone level 9.2%, and estradiol level 2.1%). Luteinizing hormone level was the most variable (CV 28%), followed by sex-steroid hormone levels (testosterone level 12% and estradiol level 13%), whereas follicle-stimulating hormone level was the least variable reproductive hormone (CV 8%). In healthy men, testosterone levels fell between 9:00 am and 5:00 pm by 14.9% (95% confidence interval 4.2, 25.5%), although morning levels correlated with (and could be predicted from) late afternoon levels in the same individual (r2 = 0.53, P<.0001). Testosterone levels were reduced more after a mixed meal (by 34.3%) than during ad libitum feeding (9.5%), after an oral glucose load (6.0%), or an intravenous glucose load (7.4%).

CONCLUSION

Quantification of the variability of a single measure of reproductive hormone levels informs the reliability of reproductive hormone assessment.

Various types of fasting diet and possible benefits in nonalcoholic fatty liver: Mechanism of actions and literature update

Non-alcoholic fatty liver disease (NAFLD) is one of the major causes of chronic liver injury, affecting around one-fourth of the general population across the world. Several important pathophysiological mechanisms underlying NAFLD include oxidative stress, inflammation, liver fibrosis, and apoptosis. Currently, therapeutic approaches are not ideal for managing NAFLD, thus new approaches and treatments are still needed. Over the last two decades, various fasting protocols have been explored to reduce body weight and improve metabolic disorders. In this review, we provide updated literature that supports fasting regimens for subjects with NAFLD and describes underlying mechanisms of action. We suggest that fasting regimens may modulate NAFLD via several mechanisms, including changes in gut microbiota, hepatic arginase, hepatic autophagy, inflammatory responses, liver functional enzymes and hepatic steatosis, fibroblast growth factors signaling, white adipose tissue browning, adipokines, circadian rhythms, lipid profiles, and body composition.

Association between length of daily siesta and brachial-ankle pulse wave velocity (baPWV): a community-based cross sectional study in North China

INTRODUCTION

To date, many studies have shown a link between siesta and cardiovascular events. Little is known regarding the connection between siesta and brachial-ankle pulse wave velocity (baPWV) levels, even though baPWV can determine the degree of atherosclerosis and vascular stiffness. Thus, we examined the relationship between siesta time and baPWV in a cross-sectional study.

METHODS

Interviews, physical examinations, lab testing, and electron beam computed tomography were all part of the baseline evaluation for participants aged older than 35. Baseline data were compared for 3 different siesta habits: irregular or no siestas, daily short siestas (1 h or less), and daily long siestas (> 1 h). Utilizing logistic regression models and multivariate linear regression, the link between siesta time and baPWV was determined.

RESULTS

Among all 6566 participants, the different siesta groups had a significant difference of the degrees of AS (P < 0.001). The same outcome was true for both males (P < 0.001) and females (P < 0.001). Numerous cardiovascular risk variables and markers of subclinical atherosclerosis were positively correlated with daily extended siestas. Results from the fully adjusted model showed that long siestas (> 60 min, OR = 1.18, 95%CI: 1.06-1.31, P = 0.002) were linked to a more severe level of the baPWV. For age or gender stratification, we found significant differences between non-siesta and > 60 min siesta groups. Multiple linear regression analysis revealed a positive connection between siesta duration and baPWV (β = 0.197, P = 0.038).

CONCLUSIONS

An elevated risk of atherosclerosis was shown to accompany prolonged siestas. These results need to be followed up on with prospective studies and additional lab work.

Relation between single nucleotide polymorphisms in circadian clock relevant genes and cholesterol metabolism

Single nucleotide polymorphisms (SNPs) in circadian clock relevant genes are associated with several metabolic health variables, but little is known about their associations with human cholesterol metabolism. Therefore, this study examined associations between SNPs in ARNTL, ARNTL2, CLOCK, CRY1, CRY2, PER2, and PER3 with the intestinal cholesterol absorption markers campesterol and sitosterol, the endogenous cholesterol synthesis marker lathosterol, and total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) concentrations in 456 healthy individuals from Western European descent. One SNP in ARNTL2 (rs1037924) showed a significant association with lathosterol. Several SNPs in ARNTL (rs4146388, rs58901760, rs6486121), ARNTL2 (rs73075788), CLOCK (rs13113518, rs35115774, rs6832769), and CRY1 (rs2078074) were significantly associated with intestinal cholesterol absorption. Genetic variants in CRY2, PER2, and PER3 were not significantly associated with intestinal cholesterol absorption or endogenous cholesterol synthesis. None of the SNPs were associated with TC or LDL-C, except for one SNP in PER2 (rs11894491) with serum LDL-C concentrations. The findings suggest that various SNPs in ARNTL, ARNTL2, CLOCK and CRY1 play a role in intestinal cholesterol absorption and endogenous cholesterol synthesis, which was not reflected in TC and LDL-C concentrations. The significant associations between SNPs and intestinal cholesterol absorption and endogenous cholesterol synthesis should be validated in other cohorts.

Four-dimensional trapped ion mobility spectrometry lipidomics for high throughput clinical profiling of human blood samples

Lipidomics encompassing automated lipid extraction, a four-dimensional (4D) feature selection strategy for confident lipid annotation as well as reproducible and cross-validated quantification can expedite clinical profiling. Here, we determine 4D descriptors (mass to charge, retention time, collision cross section, and fragmentation spectra) of 200 lipid standards and 493 lipids from reference plasma via trapped ion mobility mass spectrometry to enable the implementation of stringent criteria for lipid annotation. We use 4D lipidomics to confidently annotate 370 lipids in reference plasma samples and 364 lipids in serum samples, and reproducibly quantify 359 lipids using level-3 internal standards. We show the utility of our 4D lipidomics workflow for high-throughput applications by reliable profiling of intra-individual lipidome phenotypes in plasma, serum, whole blood, venous and finger-prick dried blood spots.

The impact of circadian rhythms on the immune response to influenza vaccination in middle-aged and older adults (IMPROVE): a randomised controlled trial

BACKGROUND

Vaccination is important in influenza prevention but the immune response wanes with age. The circadian nature of the immune system suggests that adjusting the time of vaccination may provide an opportunity to improve immunogenicity. Our previous cluster trial in Birmingham suggested differences between morning and afternoon vaccination for some strains in the influenza vaccine in older adults. Whether this effect is also seen in a younger age group with less likelihood of compromised immunity is unknown. We therefore conducted an individual-based randomized controlled trial in Guangzhou to test the hypothesis that influenza vaccination in the morning induces a stronger immune response in older adults than afternoon vaccination. We included adults in middle age to determine if the effect was also seen in younger age groups.

RESULTS

Of the 418 participants randomised, 389 (93.1%, 191 middle-aged adults aged 50-60 years and 198 older adults aged 65-75 years) were followed up. Overall, there was no significant difference between the antibody titers (geometric mean /95% CI) after morning vs afternoon vaccination (A/H1N1: 39.9 (32.4, 49.1) vs. 33.0 (26.7, 40.7), p = 0.178; A/H3N2: 92.2 (82.8, 102.7) vs. 82.0 (73.8, 91.2), p = 0.091; B: 15.8 (13.9, 17.9) vs. 14.4 (12.8, 16.3), p = 0.092), respectively. However, in pre-specified subgroup analyses, post-vaccination titers for morning versus afternoon vaccination in the 65-75 years subgroup were (A/H1N1): 49.5 (36.7, 66.6) vs. 32.9 (24.7, 43.9), p = 0.050; (A/H3N2): 93.5 (80.6, 108.5) vs. 73.1 (62.9, 84.9), p = 0.021; (B): 16.6 (13.8, 20.1) vs. 14.4 (12.3, 17.0), p = 0.095, respectively. Among females, antibody titers for morning versus afternoon vaccination were (A/H1N1): 46.9 (35.6, 61.8) vs. 31.1 (23.8, 40.7), p = 0.030; (A/H3N2): 96.0 (83.5, 110.3) vs. 84.7 (74.4, 96.5), p = 0.176; (B): 14.8 (12.7, 17.3) vs. 13.0 (11.3, 14.9), p = 0.061, respectively. In the 50-60 years old subgroup and males, there were no significant differences between morning and afternoon vaccination.

CONCLUSIONS

Morning vaccination may enhance the immunogenicity to influenza vaccine in adults aged over 65 and women. An intervention to modify vaccination programs to vaccinate older individuals in the morning is simple, cost free and feasible in most health systems.

Chronovaccination: Harnessing circadian rhythms to optimize immunisation strategies

Vaccination, as a public health measure, offers effective protection of populations against infectious diseases. Optimising vaccination efficacy, particularly for higher-risk individuals, like the elderly whose immunocompromised state can prevent the development of robust vaccine responses, is vital. It is now clear that 24-hour circadian rhythms, which govern virtually all aspects of physiology, can generate oscillations in immunological responses. Consequently, vaccine efficacy may depend critically on the time of day of administration(s), including for Covid-19, current vaccines, and any future diseases or pandemics. Published clinical vaccine trials exploring diurnal immune variations suggest this approach could represent a powerful adjunct strategy for optimising immunisation, but important questions remain to be addressed. This review explores the latest insights into diurnal immune variation and the outcomes of circadian timing of vaccination or 'chronovaccination'.

The Circadian Axis and Cardiometabolic Syndrome

Circadian rhythm refers to the daily physiologically fluctuating patterns of systemic processes that occur within a circa 24-hour timeframe, independently of external factors. There is evidence that in time, external and internal cycle misalignment leads to severe health consequences, resulting in the development of cardiometabolic disturbances. Desynchronized hormonal fluctuations along with daily specific macronutrient utilization patterns are also discussed, which by consequence, are all predictors of metabolic syndrome. The aim of this paper is to provide insight on the circadian clock’s organization throughout the human body and to explain the underlying genetic background. By understanding these well-established molecular mechanisms and processes, we believe this paper will provide accuracy regarding the importance of the circadian clock’s integrity and will highlight its role in the etiopathology of cardiometabolic syndrome.

Daytime Lipid Metabolism Modulated by CLOCK Gene Is Linked to Retinal Ganglion Cells Damage in Glaucoma

Lipid metabolism is intimately linked to circadian mechanisms and light signaling. Deteriorated photic transduction because of retinal ganglion cell (RGC) loss occurring with glaucoma progression reduces perceived light amplitude, causing circadian disruption. To investigate associations with RGCs, total cholesterol (TC), its low-density (LDL-C) and high-density (HDL-C) fractions, and triglycerides (TG) were measured, under a controlled meal regimen, during daytime hours in 114 patients diagnosed with primary open-angle glaucoma (POAG). RGC damage was assessed by high-definition optical coherence tomography (HD-OCT). Analysis of eight clock, clock-related, and melatonin receptor gene polymorphisms was performed on 19 patients. RGC loss was associated with changes in lipid metabolism in a time-dependent manner. Morning (08:00) values of HDL-C (r = 0.613, p < 0.0001) and TG (r = 0.568, p < 0.0001) correlated positively with RGC global loss, while LDL-C at 08:00 had a weak correlation (r = 0.235; p = 0.012) but showed a strong correlation in the evening (20:00) (r = 0.533, p < 0.0001). The morning–evening gradients (MEGs, changes at 20:00 versus 08:00) in TC and LDL-C changed sign from a negative to a positive association in patients exceeding the 15% two-eye mean GLV threshold. MEG (LDL-C higher in the evening than in the morning) was positive only in POAG patients with the CLOCK_3111 TT genotype.

Mutual Shaping of Circadian Body-Wide Synchronization by the Suprachiasmatic Nucleus and Circulating Steroids

Background

Steroids are lipid hormones that reach bodily tissues through the systemic circulation, and play a major role in reproduction, metabolism, and homeostasis. All of these functions and steroids themselves are under the regulation of the circadian timing system (CTS) and its cellular/molecular underpinnings. In health, cells throughout the body coordinate their daily activities to optimize responses to signals from the CTS and steroids. Misalignment of responses to these signals produces dysfunction and underlies many pathologies.

Questions Addressed

To explore relationships between the CTS and circulating steroids, we examine the brain clock located in the suprachiasmatic nucleus (SCN), the daily fluctuations in plasma steroids, the mechanisms producing regularly recurring fluctuations, and the actions of steroids on their receptors within the SCN. The goal is to understand the relationship between temporal control of steroid secretion and how rhythmic changes in steroids impact the SCN, which in turn modulate behavior and physiology.

Evidence Surveyed

The CTS is a multi-level organization producing recurrent feedback loops that operate on several time scales. We review the evidence showing that the CTS modulates the timing of secretions from the level of the hypothalamus to the steroidogenic gonadal and adrenal glands, and at specific sites within steroidogenic pathways. The SCN determines the timing of steroid hormones that then act on their cognate receptors within the brain clock. In addition, some compartments of the body-wide CTS are impacted by signals derived from food, stress, exercise etc. These in turn act on steroidogenesis to either align or misalign CTS oscillators. Finally this review provides a comprehensive exploration of the broad contribution of steroid receptors in the SCN and how these receptors in turn impact peripheral responses.

Conclusion

The hypothesis emerging from the recognition of steroid receptors in the SCN is that mutual shaping of responses occurs between the brain clock and fluctuating plasma steroid levels.

Elements to increase translation in pyrethroid epidemiology research: A review

Pyrethroid insecticides have been the subject of numerous epidemiology studies in the past two decades. We examined the pyrethroids epidemiology literature published between 2016 and 2021. Our objective with this exercise was to inform interested readers regarding information on methodological elements that strengthen a study's use for translation (i.e., use in risk assessment) and to describe aspects of future research methods that could improve utility for decision-making. We focused on the following elements: (i) study design that provided evidence that pyrethroid exposure preceded the outcome, (ii) evidence that the method used for exposure characterization was reliable and sufficiently accurate for the intended purpose, and (iii) use of a robust approach for outcome ascertainment. For each of the 74 studies identified via the literature search, we categorized the methodological elements as Acceptable or Supplemental. A study with three Acceptable elements was considered Relevant for risk assessment purposes. Based on our evaluative approach, 18 (24%) of the 74 publications were considered to be Relevant. These publications were categorized as Acceptable for all three elements assessed: confirmed exposure (N = 24), confirmed outcome (N = 64), exposure preceded the outcome (N = 44). Three of these studies were birth cohorts. There were 15 Relevant publications of adults which included 10 Agricultural Health Study cohort publications of self-reported permethrin. Overall, the majority of the reviewed studies used methods that did not permit a determination that pyrethroid exposure preceded the outcome, and/or did not utilize robust methods for exposure assessment and outcome ascertainment. There is an opportunity for investigators and research sponsors to build on the studies reviewed here and to incorporate more translational approaches to studying exposure/outcome associations related to pesticides and other chemicals.

Late-afternoon endurance exercise is more effective than morning endurance exercise at improving 24-h glucose and blood lipid levels

BACKGROUND

Glucose and lipid tolerance reportedly exhibit diurnal variations, being lower in the evening than in the morning. Therefore, the effects of exercise on glucose and blood lipid levels at different times of the day may differ. This study aimed to investigate the effects of short-term endurance exercise intervention in the morning versus late afternoon on 24-h blood glucose variability and blood lipid levels.

METHODS

Twelve healthy young men participated in a randomized crossover trial. The participants were assigned to morning (09:00-11:00) or late afternoon (16:00-18:00) endurance exercise for a week, consisting of supervised exercise sessions on Mondays, Wednesdays, and Fridays. In the morning and evening trials, the participants walked for 60 min on a treadmill at approximately 60% of maximal oxygen uptake (VO_2max). Following a 2-week wash-out period, the participants performed the exercise training regimen at another time point. Continuous glucose monitoring was used to evaluate blood glucose fluctuations during each 24-h trial period. Blood samples were collected before and after each intervention to examine blood lipid and hormonal responses.

RESULTS

Examination of the area under the curve (AUC) of the glucose level changes for 24 h after the late afternoon versus morning exercise intervention revealed significantly lower values for the former versus the latter (P < 0.01). The AUC of glucose level changes after each meal was also lower after the late afternoon versus morning intervention, and significantly lower values were observed in the late afternoon versus morning trial for breakfast and dinner (P < 0.05, P < 0.01). In addition, a significant decrease in triglycerides (TG) and TG/high-density lipoprotein cholesterol (HDL-C) was noted after versus before the late afternoon intervention (P < 0.05).

CONCLUSIONS

These results suggest that late afternoon endurance exercise is more effective than morning endurance exercise at improving 24-h glucose and triglyceride levels.

Circadian Rhythm Effects on the Molecular Regulation of Physiological Systems

Nearly every system within the body contains an intrinsic cellular circadian clock. The circadian clock contributes to the regulation of a variety of homeostatic processes in mammals through the regulation of gene expression. Circadian disruption of physiological systems is associated with pathophysiological disorders. Here, we review the current understanding of the molecular mechanisms contributing to the known circadian rhythms in physiological function. This article focuses on what is known in humans, along with discoveries made with cell and rodent models. In particular, the impact of circadian clock components in metabolic, cardiovascular, endocrine, musculoskeletal, immune, and central nervous systems are discussed. © 2021 American Physiological Society. Compr Physiol 11:1-30, 2021.

Self-Monitoring of Urinary Hormones in Combination with Telemedicine - a Timely Review and Opinion Piece in Medically Assisted Reproduction

Cycle monitoring via ultrasound and serum-based hormonal assays during medically assisted reproduction (MAR) can provide information on ovarian response and assist in optimizing treatment strategies in addition to reducing complications such as ovarian hyperstimulation syndrome (OHSS). Two surveys conducted in 2019 and 2020, including overall 24 fertility specialists from Europe, Asia and Latin America, confirmed that the majority of fertility practitioners routinely conduct hormone monitoring during MAR. However, blood tests may cause inconvenience to patients. The reported drawbacks of blood tests identified by the survey included the validity of results from different service providers, long waiting times and discomfort to patients due to travelling to clinics for tests and repeated venepunctures. Historically, urine-based assays were used by fertility specialists in clinics but were subsequently replaced by more practical and automated serum-based assays. A remote urine-based hormonal assay could be an alternative to current serum-based testing at clinics, reducing the inconvenience of blood tests and the frequency of appointments, waiting times and patient burden. Here we provide an overview of the current standard of care for cycle monitoring and review the literature to assess the correlation between urine-based hormonal assays and serum-based hormonal assays during MAR. In addition, in this review, we discuss the evidence supporting the introduction of remote urine-based hormonal monitoring as part of a novel digital health solution that includes remote ultrasound and tele-counselling to link clinics and patients at home.

Circadian rhythm and time-of-day-effects of (anti)oxidant biomarkers for epidemiological studies

Various biomarkers of oxidative stress and redox status have been used in a number of clinical and epidemiological studies related to diseases and conditions that involve disturbances of the redox balance. However, a comprehensive study of diurnal variations of a set of biomarkers has not been conducted so far. Therefore, the aim of this study is to investigate circadian rhythm and time-of-day-effects of a set of frequently used biomarkers of oxidative stress, redox and antioxidant status in serum/plasma. These biomarkers include Reactive Oxygen Metabolites (ROM), Biological Antioxidant Potency (BAP), Total Thiols in Proteins (TTP), high-sensitive C-Reactive Protein (CRP) and Uric Acid (UA). During a 24-hr study, blood sampling was conducted 6 times at 4-hr intervals. The presence of circadian rhythm was analyzed with CircWave analysis, whereas the effect of time was analyzed with Repeated Measures ANOVA (RM-ANOVA). Thereby, the main focus was on the time points in working hours (8, 12 and 16 hr), which are used frequently in practice. Of all investigated biomarkers, only TTP in males demonstrated statistically significant circadian rhythm (p = 0.040). A statistically significant effect between all six time points with RM-ANOVA was observed for ROM, TTP and UA in both genders, and for BAP in females only. No statistically significant differences were observed between the time points 8 hr and 12 hr for any of the biomarkers that were assessed in our study. In conclusion, diurnal variations in some of the studied biomarkers that we demonstrate here should be taken into account when designing and conducting clinical and epidemiological studies. It is advised to standardize the time of sampling with a preference in the morning hours.

Circadian rhythm influences induction of trained immunity by BCG vaccination

BACKGROUNDThe antituberculosis vaccine bacillus Calmette-Guérin (BCG) reduces overall infant mortality. Induction of innate immune memory, also termed trained immunity, contributes toward protection against heterologous infections. Since immune cells display oscillations in numbers and function throughout the day, we investigated the effect of BCG administration time on the induction of trained immunity.METHODSEighteen volunteers were vaccinated with BCG at 6 pm and compared with 36 age- and sex-matched volunteers vaccinated between 8 am and 9 am. Peripheral blood mononuclear cells were stimulated with Staphylococcus aureus and Mycobacterium tuberculosis before, as well as 2 weeks and 3 months after, BCG vaccination. Cytokine production was measured to assess the induction of trained immunity and adaptive responses, respectively. Additionally, the influence of vaccination time on induction of trained immunity was studied in an independent cohort of 302 individuals vaccinated between 8 am and 12 pm with BCG.RESULTSCompared with evening vaccination, morning vaccination elicited both a stronger trained immunity and adaptive immune phenotype. In a large cohort of 302 volunteers, early morning vaccination resulted in a superior cytokine production capacity compared with later morning. A cellular, rather than soluble, substrate of the circadian effect of BCG vaccination was demonstrated by the enhanced capacity to induce trained immunity in vitro in morning- compared with evening-isolated monocytes.CONCLUSIONSBCG vaccination in the morning induces stronger trained immunity and adaptive responses compared with evening vaccination. Future studies should take vaccine administration time into account when studying specific and nonspecific effects of vaccines; early morning should be the preferred moment of BCG administration.FUNDINGThe Netherlands Organization for Scientific Research, the European Research Council, and the Danish National Research Foundation.

Normalized Testosterone Glucuronide as a Potential Urinary Biomarker for Highly Variable UGT2B17 in Children 7-18 Years

UDP-glucuronosyltransferase 2B17 (UGT2B17) is a highly variable androgen-metabolizing and drug-metabolizing enzyme. UGT2B17 exhibits a unique ontogeny profile characterized by a dramatic increase in hepatic protein expression from prepubertal age to adulthood. Age, sex, copy number variation (CNV), and single nucleotide polymorphisms only explain 26% of variability in protein expression, highlighting the need for a phenotypic biomarker for predicting interindividual variability in glucuronidation of UGT2B17 substrates. Here, we propose testosterone glucuronide (TG) normalized by androsterone glucuronide (TG/AG) as a urinary UGT2B17 biomarker, and examine the associations among urinary TG/AG and age, sex, and CNV. We performed targeted metabolomics of 12 androgen conjugates with liquid-chromatography tandem mass spectrometry in 63 pediatric subjects ages 7-18 years followed over 7 visits in 3 years. Consistent with the reported developmental trajectory of UGT2B17 protein expression, urinary TG/AG is significantly associated with age, sex, and CNV. In conclusion, TG/AG shows promise as a phenotypic urinary UGT2B17 biomarker.

Peripheral blood neuroendocrine hormones are associated with clinical indices of sport-related concussion

The purpose of this study was to evaluate the relationship between neuroendocrine hormones and clinical recovery following sport-related concussion (SRC). Ninety-five athletes (n = 56 male, n = 39 female) from a cohort of 11 interuniversity sport teams at a single institution provided blood samples; twenty six athletes with SRC were recruited 2–7 days post-injury, and 69 uninjured athletes recruited prior to the start of their competitive season. Concentrations of seven neuroendocrine hormones were quantitated in either plasma or serum by solid-phase chemiluminescent immunoassay. The Sport Concussion Assessment Tool version 5 (SCAT-5) was used to evaluate symptoms at the time of blood sampling in all athletes. Multivariate partial least squares (PLS) analyses were used to evaluate the relationship between blood hormone concentrations and both (1) time to physician medical clearance and (2) initial symptom burden. A negative relationship was observed between time to medical clearance and both dehydroepiandrosterone sulfate (DHEA-S) and progesterone; a positive relationship was found between time to medical clearance and prolactin. Cognitive, somatic, fatigue and emotion symptom clusters were associated with distinct neuroendocrine signatures. Perturbations to the neuroendocrine system in athletes following SRC may contribute to initial symptom burden and longer recovery times.

Clinically significant intra-day variability of serum progesterone levels during the final day of oocyte maturation: a prospective study with repeated measurements

STUDY QUESTION

Is there significant variability in progesterone levels during the final day of oocyte maturation in women undergoing ovarian stimulation?

SUMMARY ANSWER

Progesterone levels drop from the basal level up to 44% during the final day of oocyte maturation in women undergoing ovarian stimulation.

WHAT IS KNOWN ALREADY

It has been suggested that elevated progesterone levels on the final day of ovarian stimulation may be related to poorer outcomes in in vitro fertilization fresh cycles due to a negative impact on the endometrium. However, despite conflicting results regarding the actual effect of progesterone on pregnancy rates and the lack of a well-established cut off, currently many IVF patients have their embryo transfer deferred when progesterone values surpass a threshold of 1.5 ng/ml on the day of ovulation triggering.

STUDY DESIGN, SIZE, DURATION

This was a prospective cohort study conducted in 22 oocyte donors of a university-affiliated fertility centre between November 2017 and January 2018. We calculated the sample size to detect a difference of 15% between the first and last progesterone measurements with a 5% false-positive rate in a two-sided test with 80% statistical power and a 95% confidence interval (CI).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Progesterone circulating levels were evaluated at four different times during the final day of oocyte maturation (08:00, 12:00, 16:00 and 20:00) before ovulation triggering in healthy oocyte donors. A flexible antagonist protocol was used, and ovarian stimulation was achieved with recombinant follicle-stimulating hormone (FSH) in all cases. The pairwise percentage differences in progesterone levels for each patient were calculated. Univariate linear regression analysis was adopted in order to evaluate variables associated with progesterone levels on the first measurement. The intra-day variability of progesterone was analysed using mixed models.

MAIN RESULTS AND THE ROLE OF CHANCE

Mean serum progesterone values at 08:00, 12:00, 16:00 and 20:00 were 1.75 ng/ml, 1.40 ng/ml, 1.06 ng/ml and 0.97 ng/ml. The progesterone difference between 08:00 and 20:00 was 0.77 (95% CI, 0.56–0.99), which is equivalent to a 44% decline in the mean progesterone values between the first (08:00) and the last determination (20:00; P < 0.001). Among those patients with basal (08:00) progesterone levels >1.5 ng/ml (n = 10), 70% (n = 7) showed levels reduced to <1.5 ng/ml on the last determination of the day (20:00). A mixed model analysis revealed that the progesterone reduction during the day was significantly associated with time and total recombinant FSH dose administered.

LIMITATIONS, REASONS FOR CAUTION

Only young healthy oocyte donors stimulated with an antagonist protocol using recombinant FSH were included. Extrapolation to the general IVF population, with different stimulation protocols and gonadotropins, needs to be confirmed.

WIDER IMPLICATIONS OF THE FINDINGS

This study suggests that a single progesterone determination on the final day of oocyte maturation is not reliable enough to make clinical decisions due to the enormous variation in progesterone during the day. Further studies are needed to better define the impact of the follicular progesterone rise on the endometrium of IVF cycles.

STUDY FUNDING/COMPETING INTEREST(S)

Funding was granted from Fundació Santiago Dexeus Font. N.P.P. received unrestricted grants and/or lectures fees from Roche Diagnostics, MSD, Merck, Ferring Pharmaceuticals, IBSA, Theramex and BESINS International, not associated with the current study. The remaining authors have no competing interests.

TRIAL REGISTRATION NUMBER

Clinicaltrials.gov NCT03366025.

Diurnal Variation of Markers for Cholesterol Synthesis, Cholesterol Absorption, and Bile Acid Synthesis: A Systematic Review and the Bispebjerg Study of Diurnal Variations

Human studies have shown diurnal rhythms of cholesterol and bile acid synthesis, but a better understanding of the role of the circadian system in cholesterol homeostasis is needed for the development of targeted interventions to improve metabolic health. Therefore, we performed a systematic literature search on the diurnal rhythms of cholesterol synthesis and absorption markers and of bile acid synthesis markers. We also examined the diurnal rhythms of the cholesterol synthesis markers lathosterol and desmosterol, and of the cholesterol absorption markers cholestanol, campesterol, and sitosterol in serum samples from the Bispebjerg study. These samples were collected every three hours over a 24-h period in healthy males (n = 24) who consumed low-fat meals. The systematic search identified sixteen papers that had examined the diurnal rhythms of the cholesterol synthesis markers lathosterol (n = 3), mevalonate (n = 9), squalene (n = 2), or the bile acid synthesis marker 7α-hydroxy-4-cholesten-3-one (C4) (n = 4). Results showed that lathosterol, mevalonate, and squalene had a diurnal rhythm with nocturnal peaks, while C4 had a diurnal rhythm with daytime peaks. Furthermore, cosinor analyses of the serum samples showed a significant diurnal rhythm for lathosterol (cosinor p < 0.001), but not for desmosterol, campesterol, sitosterol, and cholestanol (cosinor p > 0.05). In conclusion, cholesterol synthesis and bile acid synthesis have a diurnal rhythm, though no evidence for a diurnal rhythm of cholesterol absorption was found under highly standardised conditions. More work is needed to further explore the influence of external factors on the diurnal rhythms regulating cholesterol homeostasis.

Free-Living Humans Cross Cardiovascular Disease Risk Categories Due to Daily Rhythms in Cholesterol and Triglycerides

Cardiovascular disease risk assessment relies on single time-point measurement of risk factors. Although significant daily rhythmicity of some risk factors (e.g., blood pressure and blood glucose) suggests that carefully timed samples or biomarker timeseries could improve risk assessment, such rhythmicity in lipid risk factors is not well understood in free-living humans. As recent advances in at-home blood testing permit lipid data to be frequently and reliably self-collected during daily life, we hypothesized that total cholesterol, HDL-cholesterol or triglycerides would show significant time-of-day variability under everyday conditions. To address this hypothesis, we worked with data collected by 20 self-trackers during personal projects. The dataset consisted of 1,319 samples of total cholesterol, HDL-cholesterol and triglycerides, and comprised timeseries illustrating intra and inter-day variability. All individuals crossed at least one risk category in at least one output within a single day. 90% of fasted individuals (n = 12) crossed at least one risk category in one output during the morning hours alone (06:00-08:00) across days. Both individuals and the aggregated group show significant, rhythmic change by time of day in total cholesterol and triglycerides, but not HDL-cholesterol. Two individuals collected additional data sufficient to illustrate ultradian (hourly) fluctuation in triglycerides, and total cholesterol fluctuation across the menstrual cycle. Short-term variability of sufficient amplitude to affect diagnosis appears common. We conclude that cardiovascular risk assessment may be augmented via further research into the temporal dynamics of lipids. Some variability can be accounted for by a daily rhythm, but ultradian and menstrual rhythms likely contribute additional variance.

Energy intake at different times of the day: Its association with elevated total and LDL cholesterol levels

BACKGROUND AND AIMS

This study examined the association between macronutrient intake at different times of the day and blood lipid levels.

METHODS AND RESULTS

The study was based on the Nutrition and Health Survey in Taiwan, a cross-sectional study of non-institutionalized and non-pregnant healthy adults (≥19-years-old). A one-day (24 h) dietary recall assessed participants' food intake. Fasting plasma triglycerides, total cholesterol, and high-density lipoprotein (HDL) cholesterol were determined. Low-density lipoprotein (LDL) cholesterol was estimated based on the Friedewald formula. According to the data of eligible subjects (n = 1283), the time of energy intake was categorized into three meal times 0500-0929 (morning), 1130-1329 (noon), and 1730-2029 (evening), along with three snack times 0930-1129 (mid-morning), 1330-1729 (afternoon), and 2030-0459 (night). Energy and macronutrient intake were calculated for the 6 time periods, based on 24 h recall data. An adjusted regression model showed that by transferring 100 kcal intake at night to the morning or noon, LDL cholesterol would be lower by 1.46 (95% CI: 2.42-0.50) and 1.27 mg/dL (95% CI: 2.24-0.30), respectively. Transferring 100 kcal of fat intake at night to earlier periods was associated with a lower LDL cholesterol level, especially transferring to noontime (significantly lower by 5.21 mg/dL, 95% CI: [7.42-2.99]) and evening (significantly lower by 3.19 mg/dL, 95% CI: [6.29-0.08]).

CONCLUSIONS

Total cholesterol and LDL cholesterol had the same pattern of association with the timing of energy intake. The study showed that elevated total and LDL cholesterol were positively associated with nighttime energy and fat intake.

Hormonal assessment of participants in a long distance walk

BACKGROUND

Exercise can disrupt homeostasis and trigger many adaptive responses in different hormonal axes. The study of hormonal interactions with physical activity is highly complex due to the number of variables, such as exercise duration, exercise intensity, individual level of training, circadian rhythm, nutritional status, and environmental conditions.

METHODS

This study was performed to assess daily variations of thyroid hormones, cortisol, testosterone, insulin and glucose during moderate to high intensity aerobic physical activity for 5 consecutive days. Sample collection was performed at baseline in the morning and in the evening, immediately after finishing the activity, on the 4 initial days of the activity. Statistical analysis was performed using software STATA V14. Continuous variables are presented as means and standard deviations, while categorical variables are presented as absolute and percentage values. We used Shapiro-Wilk, Wilcoxon Sign, Mann-Whitney and Student's T test, according the needs.

RESULTS

The adrenocorticotropic axis showed an initial increase in the evening cortisol level compared to the baseline level in the morning (17.46 μg/dL and 15.97 μg/dL, respectively) and then exhibited a significant reduction between the 1st and 4th day of activity (17.46 μg/dL and 8.39 μg/dL, respectively; P = 0.001). The same pattern was observed for free thyroxine (T4) between the 1st and 4th day (1.31 and 1.14, respectively; P < 0.001).

CONCLUSIONS

Moderate to intense long duration physical activity resulted in little variation in the hormones assessed, with a trend toward reduced levels of cortisol and free T4. These findings highlight an adaptive hormonal mechanism in response to stress that is repeated daily, as shown by cortisol and thyroid function in our study.

Circadian regulation of glucose, lipid, and energy metabolism in humans

The circadian system orchestrates metabolism in daily 24-hour cycles. Such rhythms organize metabolism by temporally separating opposing metabolic processes and by anticipating recurring feeding-fasting cycles to increase metabolic efficiency. Although animal studies demonstrate that the circadian system plays a pervasive role in regulating metabolism, it is unclear how, and to what degree, circadian research in rodents translates into humans. Here, we review evidence that the circadian system regulates glucose, lipid, and energy metabolism in humans. Using a range of experimental protocols, studies in humans report circadian rhythms in glucose, insulin, glucose tolerance, lipid levels, energy expenditure, and appetite. Several of these rhythms peak in the biological morning or around noon, implicating earlier in the daytime is optimal for food intake. Importantly, disruptions in these rhythms impair metabolism and influence the pathogenesis of metabolic diseases. We therefore also review evidence that circadian misalignment induced by mistimed light exposure, sleep, or food intake adversely affects metabolic health in humans. These interconnections among the circadian system, metabolism, and behavior underscore the importance of chronobiology for preventing and treating type 2 diabetes, obesity, and hyperlipidemia.

Thyroid function, phthalate exposure and semen quality: Exploring associations and mediation effects in reproductive-aged men

BACKGROUND

A normal thyroid physiology is crucial for the maintenance of male reproductive health. Changes in thyroid hormones may represent an intermediate biological mechanism linking phthalate exposure and potential adverse health effects on male reproduction.

OBJECTIVE

To investigate the mediating role of thyroid function on the association between phthalate exposure and semen quality.

METHOD

Serum thyroid hormones, semen quality and repeated measures of urinary phthalate metabolites were determined among 509 reproductive-aged men in Wuhan, China. Cross-sectional associations between urinary phthalate metabolites, serum thyroid hormones and semen quality were explored using multivariable linear regressions. A mediation analysis was conducted to explore the role of thyroid function on the association of phthalate exposure with semen quality.

RESULTS

Significant dose-dependent relationships were found across quartiles of monoethyl phthalate (MEP) with decreasing serum free thyroxine (FT4), which, in turn, was negatively associated with percentage of normal morphology (p for trend = 0.04). Also, we found that the proportions of di-(2-ethylhexyl)-phthalate metabolites excreted as mono-(2-ethylhexyl) phthalate (%MEHP) were negatively associated with serum thyroid-stimulating hormone (TSH) (all p for trends <0.05), which, in turn, was positively associated with progressive and total sperm motility (p for trends = 0.04 and 0.03, respectively). The mediation analysis indicated that higher urinary MEP was significantly associated with a decreasing percentage of normal morphology after controlling for thyroid hormones, and 17% of the association was mediated by serum FT4.

CONCLUSIONS

Higher urinary MEP and %MEHP were associated with decreasing serum thyroid hormones, which in turn were associated with altered semen quality. Mediation analysis indicated that serum FT4 was a possible mediator of the association between urinary MEP and proportion of normal sperm morphology.

Cortisol awakening response and emotion at extreme altitudes on Mount Kangchenjunga

The cortisol awakening response (CAR) was examined over a 45days stay at extreme altitudes (above of about 5500m) on Mount Kangchenjunga. The CAR refers to a peak cortisol response during the waking period that is superimposed to the diurnal rhythmicity in cortisol secretion, whose function has been proposed to be the anticipation of demands of the upcoming day (the CAR anticipation hypothesis). According to this hypothesis, we distinguished between resting days on which the expedition team engaged in routine activities in the base camp, and ascent days on which it planned to climb up a very demanding track. We were also interested in examining the association of testosterone with emotional anticipation, given the role of this steroid hormone in reward-related processes in challenge situations. Results showed that the climber group had a bigger CAR on ascent days, relative to the Sherpa group at the same altitude and the non-climber group at sea level. Several methodological issues, however, made it difficult to interpret these group differences in terms of the CAR anticipation hypothesis (e.g. a seemingly influential covariate was awakening time). Although based on tentative results, correlational and regression analyses controlling for awakening time coherently showed that the CAR was associated with anticipation of a hard day and feelings of fear, and testosterone was associated with feelings of energy and positive affect. Whether or not the anticipation of a hard day played a key role in regulation of the CAR, the observation of an intact CAR in the climber group under hypobaric hypoxia conditions would require in-depth reflection from the perspective of human adaptive evolution.

Acutely developing, spurious anaemia without actual blood loss. A paradigmatic case report

We describe the case of a 55-year old women admitted at night to the emergency department (ED), complaining for acute abdominal pain lasting for nearly 5 hours. A first blood testing, performed immediately after admission, revealed mild anaemia. A second blood sample, drawn two hours after admission, revealed a considerable decrease of haemoglobin, haematocrit, total white blood cell and platelet counts (between 10-15% reduction). Abdominal ultrasonography was normal and the patient had no signs or symptoms of internal or external haemorrhage. Pre-analytical and analytical errors were accurately excluded. No infusion therapy was administered. After thoughtful discussing the sequence of events, it was ascertained that the first set of blood samples was drawn with the patient in seated position, immediately after ED admission (i.e., approximately 1 min passed from standing to seated position before venipuncture), whereas the second set of blood samples was drawn with the patient lying for two hours in supine position. This case report highlights the importance of standardizing patient position before venous blood collection, along with the crucial role played by cooperation and communication between laboratory and clinical wards for identifying and troubleshooting potential causes of spurious results of in vitro diagnostic testing.

Daily levels and rhythm in circulating corticosterone and insulin are altered with photostimulated seasonal states in night-migratory blackheaded buntings

The circadian rhythms are involved in the photostimulation of seasonal responses in migratory blackheaded buntings. Here, we investigated whether changes in daily levels and rhythm in corticosterone (cort) and insulin secretions were associated with transitions in the photoperiodic seasonal states. Buntings were exposed to short days to maintain the winter (photosensitive) non-migratory state, and to long days for varying durations to induce the premigratory, migratory (shown by migratory restlessness at night, Zugunruhe) and summer non-migratory (photorefractory) states. We monitored activity patterns, and measured plasma cort and insulin levels at six and four times, respectively, over 24h in each seasonal state. Buntings were fattened and weighed heavier, and exhibited intense nighttime activity in the migratory state. The daytime activity patterns also showed seasonal differences, with a bimodal pattern with morning and evening activity bouts only in the summer non-migratory state. Further, the average baseline hormone levels were significantly higher in premigratory and migratory than in the winter non-migratory state. Both cort and insulin levels showed a significant daily rhythm, but with seasonal differences. Whereas, cort rhythm acrophases (estimated time of peak secretion over 24h) were at night in the winter non-migratory, premigratory and migratory states, the insulin rhythm acrophases were found early in the day and night in winter and summer non-migratory states, respectively. These results suggest that changes in daily levels and rhythm in cort and insulin mediate changes in the physiology and behavior with photostimulated transition in seasonal states in migratory blackheaded buntings.

Different DHEA-S Levels and Response Patterns in Individuals with Chronic Neck Pain, Compared with a Pain Free Group-a Pilot Study

Objective

To test, in this pilot study, whether DHEA-S (Dehydroepiandrosterone, sulfated form) plasma levels are lower among persons with chronic neck pain, compared to control persons, and to investigate the DHEA-S response after a physical exercise.

Subjects

Included were 12 persons with chronic neck pain and eight controls without present pain, all 18 and 65 years of age. Exclusion criteria for both groups were articular diseases or tendinosis, fibromyalgia, systemic inflammatory and neuromuscular diseases, pain conditions due to trauma, or severe psychiatric diseases.

Design and methods

The participants arm-cycled on an ergometer for 30 minutes. Blood samples were taken before, 60 minutes, and 150 minutes after this standardized physical exercise.

Results

The estimated plasma DHEA-S levels at baseline were 2.0 µmol/L (95% confidence interval [CI] 1.00; 4.01) in the pain group and 4.1 µmol/L (95% CI2.0; 8.6) in the control group, adjusted for sex, age, body mass index (BMI), and Shirom-Melamed Burnout Questionnaire (SMBQ), with a ratio of 0.48 ( P  = 0.094).

Conclusions

In this pilot study, the plasma DHEA-S levels appeared to be lower among the persons with chronic neck pain, compared with the control group. It was indicated that DHEA-S decreased during the physical exercise in the control group, and either increased or was unaffected in the chronic pain group.

Biallelic Mutations in DNAJC12 Cause Hyperphenylalaninemia, Dystonia, and Intellectual Disability

Phenylketonuria (PKU, phenylalanine hydroxylase deficiency), an inborn error of metabolism, can be detected through newborn screening for hyperphenylalaninemia (HPA). Most individuals with HPA harbor mutations in the gene encoding phenylalanine hydroxylase (PAH), and a small proportion (2%) exhibit tetrahydrobiopterin (BH4) deficiency with additional neurotransmitter (dopamine and serotonin) deficiency. Here we report six individuals from four unrelated families with HPA who exhibited progressive neurodevelopmental delay, dystonia, and a unique profile of neurotransmitter deficiencies without mutations in PAH or BH4 metabolism disorder-related genes. In these six affected individuals, whole-exome sequencing (WES) identified biallelic mutations in DNAJC12, which encodes a heat shock co-chaperone family member that interacts with phenylalanine, tyrosine, and tryptophan hydroxylases catalyzing the BH4-activated conversion of phenylalanine into tyrosine, tyrosine into L-dopa (the precursor of dopamine), and tryptophan into 5-hydroxytryptophan (the precursor of serotonin), respectively. DNAJC12 was undetectable in fibroblasts from the individuals with null mutations. PAH enzyme activity was reduced in the presence of DNAJC12 mutations. Early treatment with BH4 and/or neurotransmitter precursors had dramatic beneficial effects and resulted in the prevention of neurodevelopmental delay in the one individual treated before symptom onset. Thus, DNAJC12 deficiency is a preventable and treatable cause of intellectual disability that should be considered in the early differential diagnosis when screening results are positive for HPA. Sequencing of DNAJC12 may resolve any uncertainty and should be considered in all children with unresolved HPA.

Parallel diurnal fluctuation of testosterone, androstenedione, dehydroepiandrosterone and 17OHprogesterone as assessed in serum and saliva: validation of a novel liquid chromatography-tandem mass spectrometry method for salivary steroid profiling

Background:

Salivary androgen testing represents a valuable source of biological information. However, the proper measurement of such low levels is challenging for direct immunoassays, lacking adequate accuracy. In the last few years, many conflicting findings reporting low correlation with the serum counterparts have hampered the clinical application of salivary androgen testing. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) makes it possible to overcome previous analytical limits, providing new insights in endocrinology practice.

Methods:

Salivary testosterone (T), androstenedione (A), dehydroepiandrosterone (DHEA) and 17OHprogesterone (17OHP) were extracted from 500µL of saliva, separated in 9.5 min LC-gradient and detected by positive electrospray ionization – multiple reaction monitoring. The diurnal variation of salivary and serum androgens was described by a four paired collection protocol (8 am, 12 am, 4 pm and 8 pm) in 19 healthy subjects.

Results:

The assay allowed the quantitation of T, A, DHEA and 17OHP down to 3.40, 6.81, 271.0 and 23.7 pmol/L, respectively, with accuracy between 83.0 and 106.1% for all analytes. A parallel diurnal rhythm in saliva and serum was observed for all androgens, with values decreasing from the morning to the evening time points. Salivary androgen levels revealed a high linear correlation with serum counterparts in both sexes (T: R>0.85; A: R>0.90; DHEA: R>0.73 and 17OHP: R>0.89; p<0.0001 for all).

Conclusions:

Our LC-MS/MS method allowed a sensitive evaluation of androgen salivary levels and represents an optimal technique to explore the relevance of a comprehensive androgen profile as measured in saliva for the study of androgen secretion modulation and activity in physiologic and pathologic states.

Serum Progesterone Levels in Pregnant Women with Obstructive Sleep Apnea: A Case Control Study

BACKGROUND

Pregnancy is a risk factor for sleep disordered breathing, including obstructive sleep apnea (OSA). Progesterone, one of the key hormones in pregnancy, a known respiratory drive stimulant, increases ventilation and may protect against OSA. We aimed to examine the relationship between circulating progesterone and OSA, after accounting for body weight and gestational age.

METHODS

A case control study was conducted of pregnant women with OSA and those at low risk for the disorder. Cases were identified by ICD-9 code and review of medical record. Controls were identified if they scored zero (never) for snoring, apnea, and gasping on the multivariable apnea prediction index questionnaire immediately following delivery. Subjects with available stored first and/or second trimester residual serum samples were then included in this study and serum analyzed for progesterone. Raw progesterone levels were adjusted for the effects of gestational age and maternal weight.

RESULTS

Twenty-seven cases and 64 controls with available serum were identified. Women with OSA had greater maternal weight and higher rates of related comorbidities, compared to controls. Progesterone levels correlated positively with gestational age and negatively with greater weight. Progesterone levels, adjusted for gestational age and maternal weight and expressed as multiples of median (MoM), were significantly lower in OSA cases compared to controls in both the first trimester (MoM = 0.71, confidence interval [95% CI] 0.60-0.83) relative to the MoM in controls of 1.00. In the second trimester levels were also lower in OSA cases (MoM = 0.84, 95% CI 0.73-0.96) compared to the MoM of 1.00 in controls.

CONCLUSIONS

Progesterone levels, after accounting for weight and gestational age, were lower in women with OSA than controls. Progesterone may play a protective role against OSA.