Neuroactive steroids in the neuroendocrine control of food intake, metabolism, and reproduction

Neuroactive steroids are a type of steroid hormones produced within the nervous system or in peripheral glands and then transported to the brain to exert their neuromodulatory effects. Neuroactive steroids have pleiotropic effects, that include promoting myelination, neuroplasticity, and brain development. They also regulate important physiological functions, such as metabolism, feeding, reproduction, and stress response. The homoeostatic processes of metabolism and reproduction are closely linked and mutually dependent. Reproductive events, such as pregnancy, bring about significant changes in metabolism, and metabolic status may affect reproductive function in mammals. In females, the regulation of reproduction and energy balance is controlled by the fluctuations of oestradiol and progesterone throughout the menstrual cycle. Neurosteroids play a key role in the neuroendocrine control of reproduction. The synthesis of neuroestradiol and neuroprogesterone within the brain is a crucial process that facilitates the release of GnRH and LH, which in turn, regulate the transition from oestrogen-negative to oestrogen-positive feedback. In addition to their function in the reproductive system, oestrogen has a key role in the regulation of energy homoeostasis by acting at central and peripheral levels. The oestrogenic effects on body weight homoeostasis are primarily mediated by oestrogen receptors-α (ERα), which are abundantly expressed in multiple brain regions that are implicated in the regulation of food intake, basal metabolism, thermogenesis, and brown tissue distribution. The tight interplay between energy balance and reproductive physiology is facilitated by shared regulatory pathways, namely POMC, NPY and kisspeptin neurons, which are targets of oestrogen regulation and likely participate in different aspects of the joint control of energy balance and reproductive function. The aim of this review is to present a summary of the progress made in uncovering shared regulatory pathways that facilitate the tight coupling between energy balance and reproductive physiology, as well as their reciprocal interactions and the modulation induced by neurosteroids.

A systematic review of the development and application of home cage monitoring in laboratory mice and rats

BACKGROUND

Traditionally, in biomedical animal research, laboratory rodents are individually examined in test apparatuses outside of their home cages at selected time points. However, the outcome of such tests can be influenced by various factors and valuable information may be missed when the animals are only monitored for short periods. These issues can be overcome by longitudinally monitoring mice and rats in their home cages. To shed light on the development of home cage monitoring (HCM) and the current state-of-the-art, a systematic review was carried out on 521 publications retrieved through PubMed and Web of Science.

RESULTS

Both the absolute (~ × 26) and relative (~ × 7) number of HCM-related publications increased from 1974 to 2020. There was a clear bias towards males and individually housed animals, but during the past decade (2011-2020), an increasing number of studies used both sexes and group housing. In most studies, animals were kept for short (up to 4 weeks) time periods in the HCM systems; intermediate time periods (4-12 weeks) increased in frequency in the years between 2011 and 2020. Before the 2000s, HCM techniques were predominantly applied for less than 12 h, while 24-h measurements have been more frequent since the 2000s. The systematic review demonstrated that manual monitoring is decreasing in relation to automatic techniques but still relevant. Until (and including) the 1990s, most techniques were applied manually but have been progressively replaced by automation since the 2000s. Independent of the year of publication, the main behavioral parameters measured were locomotor activity, feeding, and social behaviors; the main physiological parameters were heart rate and electrocardiography. External appearance-related parameters were rarely examined in the home cages. Due to technological progress and application of artificial intelligence, more refined and detailed behavioral parameters have been investigated in the home cage more recently.

CONCLUSIONS

Over the period covered in this study, techniques for HCM of mice and rats have improved considerably. This development is ongoing and further progress as well as validation of HCM systems will extend the applications to allow for continuous, longitudinal, non-invasive monitoring of an increasing range of parameters in group-housed small rodents in their home cages.

P968Impact of contact force sensing catheters on fluoroscopy time in left-sided atrial procedures

Funding Acknowledgements

None.

OnBehalf

Go for Zero Fluoroscopy Project investigators

Background Contact force sensing catheters provide electrophysiologists with direct feedback and therefore improve safety and help to generate more effective lesions. The use of contact force may also reduce fluoroscopy and procedure times.

Purpose The aim of this study was to systematically evaluate the impact of using contact force sensing catheters (CFSCs) on fluoroscopy times and procedure times in left-sided atrial procedures.

Methods In this multinational, multicenter study, data from 622 left-sided procedures (142 without and 480 with CFSCs) of 25 participating European centers were prospectively collected with a structured questionnaire. Examinations comprised 393 pulmonary vein isolations (PVIs, group 1[G1]), 122 PVIs with linear lesions (group 2[G2]), 65 left-sided accessory pathway ablations (group 3 [G3]) and 42 ablations for left atrial tachycardia (group 4 [G4]). Fluoroscopy and procedure times were compared with respect to the use of CFSCs, procedure type, and level of operator experience as possible confounders. A Mann-Whitney U-test was applied for comparison, and a p-value <0.05 was considered statistically significant.

Results With the use of CFSCs, fluoroscopy time was significantly reduced when performing pulmonary vein isolations (G1 median [IQR]: 19 [11.0-33.7] vs. 7.2 [4.0-13.0] min., p < 0.001, G2: 45.3 [34.9-61.8] vs. 7.3 [5.0-14.0], p < 0.001, respectively). For groups G3 and G4, no difference could be detected. Procedure times were shortened for pulmonary vein isolations with additional lesions only (G4: 210 [180-240] vs. 153 [127-200] min., p < 0.001). When assessing the effect of operator experience, all left-sided atrial procedures were combined. Significantly shorter fluoroscopy times with contact force were found at all career levels (early career < 5 years: median -6 min., p = 0.024, mid-career 5-15 years: -15 min., p < 0.001, mentor status with experience > 15 years: -6.5 min., p < 0.001). The use of contact force proved to be especially beneficial in reducing fluoroscopy time in operators performing one to 19 procedures per month (1-9: median -15.8 min., p < 0.001, 10-19: -15.9 min., p < 0.001), whereas it lost its statistical significance when more than 20 procedures per month were performed (20-39: - 3.2 min., p = 0.100, >40: -1.5 min., p = 0.346).

Conclusion Contact force sensing catheters can help to reduce fluoroscopy times, especially when performing pulmonary vein isolations. This effect could be demonstrated for all career levels. However, it diminished with the operator"s caseload. A shortening of procedure time was found for PVIs with additional linear lesions.

Effects of high-intensity interval training and nutrition advice on cardiometabolic markers and aerobic fitness in adolescent girls with obesity

The aim of the study was to compare the effects of high-intensity interval training (HIIT) and nutrition advice on cardiometabolic biomarkers, hormonal parameters, and cardiorespiratory fitness in adolescent girls with obesity. Adolescent girls with obesity (n = 44, aged 13-19 years) were randomized into a 12-week intervention as follows: (i) dietary advice and HIIT (n = 22), and (ii) dietary advice only (n = 22). The concentration of biomarkers of inflammation, biochemical and hormonal testing, oral glucose tolerance test, cardiorespiratory fitness, physical activity levels, and nutrition were assessed. After a 3-month intervention, the diet+HIIT group significantly increased insulin sensitivity index (-0.34 ± 1.52 vs. 1.05 ± 3.21; p = 0.001) and work load (0.6 ± 11.3 W vs. 14.6 ± 20.2 W; p = 0.024) and decreased glucose area under the curve (-0.29 ± 4.69 vs. -0.98 ± 4.06; p = 0.040), insulin area under the curve (-9.65 ± 117.9 vs. -98.7 ± 201.8; p = 0.003), and high-sensitivity C-reactive protein (hs-CRP) (0.12 ± 1.92 mg/L vs. -1.47 ± 3.67 mg/L; p = 0.039) in comparison with the diet group. Regarding within-group changes, both groups had significant improvements in body mass index (BMI), BMI-standard deviation score, body fat percentage, and systolic blood pressure. Positive impact on waist circumference, waist circumference/height ratio, diastolic blood pressure, hs-CRP, work load, maximal heart rate, and resting heart rate was observed only after the diet+HIIT intervention. No significant change was noted in peak oxygen uptake, lipid profile, and hormonal parameters between groups after intervention. Novelty HIIT and nutrition advice increased insulin sensitivity and decreased BMI, body fat, systolic blood pressure, and diastolic blood pressure. Nutrition advice decreased BMI, body fat, and systolic blood pressure in adolescent girls with obesity.

The ESC ACCA EAPCI EORP acute coronary syndrome ST-elevation myocardial infarction registry

Aims 

The Acute Cardiac Care Association (ACCA)–European Association of Percutaneous Coronary Intervention (EAPCI) Registry on ST-elevation myocardial infarction (STEMI) of the EurObservational programme (EORP) of the European Society of Cardiology (ESC) registry aimed to determine the current state of the use of reperfusion therapy in ESC member and ESC affiliated countries and the adherence to ESC STEMI guidelines in patients with STEMI.

Methods and results 

Between 1 January 2015 and 31 March 2018, a total of 11 462 patients admitted with an initial diagnosis of STEMI according to the 2012 ESC STEMI guidelines were enrolled. Individual patient data were collected across 196 centres and 29 countries. Among the centres, there were 136 percutaneous coronary intervention centres and 91 with cardiac surgery on-site. The majority of centres (129/196) were part of a STEMI network. The main objective of this study was to describe the demographic, clinical, and angiographic characteristics of patients with STEMI. Other objectives include to assess management patterns and in particular the current use of reperfusion therapies and to evaluate how recommendations of most recent STEMI European guidelines regarding reperfusion therapies and adjunctive pharmacological and non-pharmacological treatments are adopted in clinical practice and how their application can impact on patients’ outcomes. Patients will be followed for 1 year after admission.

Conclusion 

The ESC ACCA-EAPCI EORP ACS STEMI registry is an international registry of care and outcomes of patients hospitalized with STEMI. It will provide insights into the contemporary patient profile, management patterns, and 1-year outcome of patients with STEMI.

Short-term sleep fragmentation enhances anxiety-related behavior: The role of hormonal alterations

Introduction

The neuroendocrine background of acute sleep fragmentation in obstructive sleep apnea and sleep fragmentation involvement in psychiatric comorbidities, common in these patients, are still largely unknown. The aim of this study was to determine the effects of short-term experimental sleep fragmentation on anxiety -like behavior and hormonal status in rats.

Methods

Male rats were adapted to treadmill (ON and OFF mode with belt speed set on 0.02m/s and 0.00m/s) and randomized to: 1) treadmill control (TC, only OFF mode); 2) motion, activity control (AC, 10min ON and 30min OFF mode) and 3) sleep fragmentation (SF, 30s ON and 90s OFF mode) group. Six hours later, the animals were tested in the open field, elevated plus maze and light/dark test (n = 8/group). Testosterone, estradiol, progesterone and corticosterone were determined in separate animal cohort immediately upon sleep fragmentation (n = 6/group).

Results

SF rats showed decreased rearings number, decreased time spent in the central area and increased thigmotaxic index compared to TC and AC rats in the open field test. Similarly, increased anxiety upon sleep fragmentation was observed in the elevated plus maze and the light/dark test. Significantly lower testosterone, estradiol and progesterone levels were determined in SF in comparison to AC and TC groups, while there was no significant difference in the levels of corticosterone.

Conclusion

Short term sleep fragmentation enhances anxiety-related behavior in rats, which could be partly mediated by the observed hormonal changes presented in the current study in form of testosterone, estradiol and progesterone depletion.

Sulfur – Containing Amino Acids in Seizures: Current State of the Art

Background:

Homocysteine and taurine are non-proteinogenic sulfur-containing amino acids with numerous important physiological roles. Homocysteine and taurine are considered to be neurotransmitters and neuromodulators, the first showing clear hyperexcitability role, while the second is known by its inhibitory and neuroprotective properties.

Objective:

In this article we addressed the role of homocysteine and its related metabolite homocysteine thiolactone in the development of seizures, focusing on its experimental models in vivo, potential mechanisms of proepileptogenic activity via interactions with glutamatergic neurotransmission, sodium pump activity, oxidative stress, cholinergic system and NO-mediated neuronal signaling, as well as the pharmacological and non-pharmacological approaches to modulate its proconvulsive activity. Additionally, herein we will focus on taurine neuroprotective effects linked with its anticonvulsive properties and mediated by taurine interactions with GABA-ergic and glutamatergic system and oxidative stress.

The effect of subchronic supplementation with folic acid and l-arginine on homocysteine-induced seizures

The aim of the present study was to examine the effect of subchronic co-administration of folic acid (F) and l-arginine (A) on behavioural and electroencephalographic (EEG) characteristics of dl homocysteine thiolactone (H) induced seizures in adult rats. The activity of membrane ATPases in different brain regions were also investigated. Rats were treated with F, A, or vehicle for 15 days (regimen: F 5 mg/kg + A 500 mg/kg (F5A500); F 10 mg/kg + A 300 mg/kg (F10A300)). Seizures were elicited by convulsive dose of H (H, F5A500H, F10A300H) Subchronic supplementation with F and A did not affect seizure incidence, number of seizure episodes, and severity in F5A500H and F10A300H groups vs. H group. However, a tendency to increase latency and decrease the number of seizure episodes was noticed in the F10A300H group. EEG mean spectral power densities during ictal periods were significantly lower in F10A300H vs. H group. The activity of Na+/K+-ATPase and Mg2+-ATPase was significantly increased in almost all examined structures in rats treated with F and A. We can conclude that subchronic supplementation with folic acid and l-arginine has an antiepileptic effect in dl homocysteine thiolactone induced epilepsy.

Anxiety-related behavior in hyperhomocysteinemia induced by methionine nutritional overload in rats: role of the brain oxidative stress

The aim of this study was to examine the effects of a methionine-enriched diet on anxiety-related behavior in rats and to determine the role of the brain oxidative status in these alterations. Adult male Wistar rats were fed from the 30th to 60th postnatal day with standard or methionine-enriched diet (double content comparing with standard diet: 7.7 g/kg). Rats were tested in open field and light-dark tests and afterwards oxidative status in the different brain regions were determined. Hyperhomocysteinemia induced by methionine-enriched diet in this study decreased the number of rearings, as well as the time that these animals spent in the center of the open field, but increased index of thigmotaxy. Oxidative status was selectively altered in the examined regions. Lipid peroxidation was significantly increased in the cortex and nc. caudatus of rats developing hyperhomocysteinemia, but unaltered in the hippocampus and thalamus. Based on the results of this research, it could be concluded that hyperhomocysteinemia induced by methionine nutritional overload increased anxiety-related behavior in rats. These proanxiogenic effects could be, at least in part, a consequence of oxidative stress in the rat brain.

Fetal and maternal plasma homocysteine levels during the second half of uncomplicated pregnancy

OBJECTIVE

To measure fetal and maternal plasma homocysteine (Hcy) concentrations in uncomplicated pregnancies.

METHODS

Paired maternal venous and fetal umbilical cord blood (n = 81) samples were evaluated for plasma Hcy and vitamin B₁₂ levels, in addition to eight neonatal umbilical cord blood samples obtained immediately following delivery.

RESULTS

Both fetal and maternal Hcy concentrations were positively correlated with advancing gestational age (ρ = 0.44, p < 0.0001; and ρ = 0.27, p < 0.05, respectively). Fetal plasma Hcy concentrations [2.2 µmol/l (IQR: 2.0-3.2)] were significantly lower than both neonatal umbilical vein [5.0 µmol/l (IQR: 4.4-6.5); p < 0.001] and maternal plasma Hcy levels [4.4 μmo/l (IQR: 3.4-5.4); p < 0.001]. In addition, Hcy values at term were higher in the umbilical vein compared with the umbilical artery [5.0 μmol/l (IQR: 3.4-5.4) versus 4.2 μmol/l (IQR: 3.7-5.5), respectively; p = 0.016]. Significant correlation was noted and between fetal and maternal Hcy levels (ρ = 0.50, p < 0.0001), while fetal Hcy was negatively correlated with maternal B₁₂ concentrations (ρ = -0.32, p < 0.001).

CONCLUSIONS

Fetal Hcy levels were significantly lower than maternal and neonatal levels and correlated with gestational age across the second half of pregnancy.

Exercise decreases susceptibility to homocysteine seizures: the role of oxidative stress

The aim of the study was to examine the effects of chronic exercise training on seizures induced by homocysteine thiolactone (HCT) in adult rats. Rats were assigned to: sedentary control; exercise control; sedentary+HCT; exercise+HCT group. Animals in the exercise groups ran 30 min daily on a treadmill for 30 consecutive days (belt speed 20 m/min), while sedentary rats spent the same time on the treadmill (speed 0 m/min). On the 31st day, the HCT groups received HCT (8.0 mmol/kg), while the control groups received vehicle. Afterwards, convulsive behavior and EEG activity were registered. Lipid peroxidation, superoxide dismutase (SOD) and catalase (CAT) activity were ascertained in the rat hippocampus. No signs of seizures were registered in sedentary and exercise control rats. Seizure latency was increased, while number of seizure episodes and spike-and-wave discharges (SWD) in EEG were decreased in the exercise+HCT compared to the sedentary+HCT group. Seizure incidence, the severity thereof and duration of SWDs were not significantly different between these groups. Exercise partly prevented increase of lipid peroxidation and decrease of the SOD and CAT activity after HCT administration. These results indicate beneficial effects of exercise in model of HCT-induced seizures in rats, what could be, at least in part, a consequence of improved antioxidant enzymes activity.