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Purpose: The latest reform of French medical studies has moved the National Ranking Examination before residency to the beginning of the sixth-year for undergraduate medical students, thus placing unprecedented workload during the preceding summer. The main objective was to determine whether study conditions and psychosocial factors were associated with student success in this model of intense workload., Materials and Methods: An online survey designed with six student-partners was sent at a French Medical School after the examination in 2023. The primary outcome was student success in achieving their main goal (Ranking, Knowledge, Well-being). A machine-learning model (eXtreme Gradient Boosting) was developed and explained using Artificial Intelligence. An AI-guided multivariate logistic regression was performed, Odd Ratios were calculated., Results: Out of 123 responses, 75 (61%) of the students achieved their main goal. Motivation and socialization during the summer were the two most important variables for predicting student success. In guided multivariate logistic regression, summer motivation (Odd Ratio = 4.12, 95%CI[1.75-10.30]), summer loneliness (Odd Ratio = 0.35, 95%CI[0.14-0.86]), and student's main goal (Ranking, Odd Ratio = 2.94, 95%CI[1.15-7.79]) were associated with student success., Conclusions: Motivation and socialization during the summer preceding high-stakes examinations are strongly predictive of undergraduate medical students' success. This study highlights the importance of well-being during summer for student success.[Box: see text].

Background: During central venous catheterization (CVC), ultrasound (US) guidance has been shown to reduce mechanical complications and increase success rates compared to the anatomical landmark (AL) technique. However, the impact of US guidance on catheter-related infections remains controversial. This systematic review and meta-analysis aimed to compare the risk of catheter-related infection with US-guided CVC versus AL technique., Methods: A systematic search on MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science databases was conducted until July 31, 2024. Randomized controlled trials (RCTs) and non-randomized studies of intervention (NRSI) comparing US-guided versus AL-guided CVC placement were included. The primary outcome was a composite outcome including all types of catheter-related infection: catheter-related bloodstream infections (CRBSIs), central line-associated bloodstream infections (CLABSIs), catheter colonization, or any other type of reported infection. The secondary outcomes included individual infection types and mortality at day-28. Subgroup analyses based on study type and operator experience were also performed., Results: Pooling twelve studies (8 RCTs and 4 NRSI), with a total of 5,092 CVC procedures (2072 US-guided and 3020 AL-guided), US-guided CVC was associated with a significant reduction in catheter-related infections compared with the AL technique (risk ratio (RR) = 0.68, 95% confidence interval (CI) 0.53-0.88). In the RCT subgroup, the pooled RR was 0.65 (95% CI 0.49-0.87). This effect was more pronounced in procedures performed by experienced operators (RR = 0.60, 95% CI 0.41-0.89). In inexperienced operators, the infection risk reduction was not statistically significant. The pooled analysis of CRBSIs and CLABSIs also favored US guidance (RR = 0.65, 95% CI 0.48-0.87)., Conclusion: US-guided CVC placement significantly reduces the risk of catheter-related infections compared to the AL technique, particularly when performed by experienced operators. Trial registration PROSPERO CRD42022350884. Registered 13 August 2022., Competing Interests: Declarations Ethics approval and consent to participate Not relevant. Consent for publication Not relevant. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Abstract: Introduction: The maximal norepinephrine (NE) dose >1 μg/kg/min during circulatory shock apparently is associated with higher mortality, but this threshold needs confirmation. This study aimed at investigating whether NE infusion at a dose >1 μg/kg/min could predict early intensive care unit (ICU) mortality (first 5 days). The secondary objective was to assess the day-by-day relationship between NE dose during the first 4 days of ICU stay and subsequent mortality. Methods: We conducted a retrospective analysis of data from ICU patients receiving NE for circulatory shock at the Nimes University Hospital (France) from January 2016 to December 2019. Results: A total of 5,735 patients were admitted, 3,693 were screened, and 3,423 were analyzed. NE infusion at a dose >1 μg/kg/min was associated with day-5 mortality (hazards ratio: 7.40, P < 0.0001). The area under the receiver operating characteristic was 0.79 to predict day-5 mortality in ICU for maximal NE >1 μg/kg/min. The calculated threshold of 1.13 μg/kg/min for maximal NE was the best prognostic value (sensitivity: 67%, specificity: 80%, positive predictive value: 45%). When the 1.2 μg/kg/min threshold was crossed either on the first, second, third, or fourth day of ICU stay, the probability of subsequent death was 47%, 49%, 60%, and 40%, respectively. Along the first 4 days of ICU stay, the risk of death increased with increasing NE infusion dose. Conclusions: An NE infusion rate >1.13 μg/kg/min predicts day-5 mortality in ICU patients with circulatory shock. The time to reach maximal NE infusion rate was shorter in survivors than in nonsurvivors., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 by the Shock Society.)

Transthoracic echocardiography is widely used in intensive care unit (ICU) to manage patients with acute circulatory failure. Recently, automated ultrasound (US) measurement applications have been developed but their clinical performance has not been evaluated yet. The aim of this study was to assess the agreement between automated and manual measurements of the velocity-time integral in the left ventricular outflow tract (VTI-LVOT) using the auto-VTI® tool. This prospective, single-center, interventional study included ICU patients with acute circulatory failure. The examination involved two successive manual measurements of VTI-LVOT (mean of 3 consecutive heartbeats in regular sinus rhythm, and 5 heartbeats in irregular rhythm), followed by a measurement using auto-VTI® software. In patients receiving a fluid challenge, trending ability in detecting fluid responsiveness was also evaluated. Seventy patients were included between January 19, 2020, and September 24, 2020, at the Nîmes University Hospital. The feasibility of the auto-VTI® was 94%. The mean difference between the two methods was 11% with limits of agreement from - 19% to 42%. The proportion of agreement at the 15% difference threshold was 68% [58%; 80%]. The precision and least significant change measured for the manual measurement of VTI were 7.4 and 10.5%, respectively, and by inference for the automated method 28% and 40%. The new auto-VTI® tool, despite interesting feasibility, demonstrated an insufficient agreement with a systematic bias and an insufficient precision limiting its implementation in critically ill patients.Clinical trial registration: ClinicalTrials.gov identifier: NCT04360304., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Introduction: The study reported the time (from the initial submission to the final decision) to evaluate a clinical research project by one of the 39 French national ethics committees. The times from this final decision to the first participant inclusion and study achievement (first patient inclusion to the end of the last patient's follow-up) were also reported., Methods: Clinical research projects submitted between January 1st 2019 and June 30th 2023 were analyzed according to their type (research on drugs, clinical investigations, performance studies, research implying human person), and the promotor (industry, university hospital, general hospital, private medical institution, others). The times of assessment of the project by the ethic committee (from the initial submission to the final decision), of the first participant inclusion (from the approval of the project) and of study achievement (first patient inclusion to the end of the last patient's follow-up) were calculated., Results: Among 467 submitted clinical research projects, 424 were approved (90.8 %). The median time [Q1-Q3] to evaluate a project was 73 days [51-98] whatever the types of projects and promotors. In 307 accepted projects, the first patient inclusion occurred after 134 days [61-237] and was being waited for 347 days [306-510] in 39 other ones. In 122 projects, the time for study achievement was 446 days [230-731]. In 185 other projects, the inclusions were still in progress for 699 days [397-1098]., Conclusion: In this concerned ethic committee, a final decision was edited after a median assessment time of 73 days (with >90 % approvals), shorter than the times to include the first patient and for achieving the study., (Copyright © 2024. Published by Elsevier Masson SAS.)

Purpose: Caustic ingestion is a potential life-threatening condition associated with high morbidity and mortality. Data on patients admitted to Intensive Care Unit (ICU) for severe caustic ingestion are lacking. We aimed to describing epidemiological features and outcomes of patients admitted to ICU for caustic ingestion in France., Methods: In a retrospective, observational, and multicenter study, data from the national French Programme de Médicalisation des Systèmes d'Informations (PMSI) database were analysed from 2013 to 2019. In-hospital mortality rate (primary outcome) and in-ICU complications (secondary outcomes) were reported and analysed., Results: 569 patients (289 males (50.8%), with median age of 49 years [interquartile (26-62)] were admitted in 65 French ICU for severe caustic ingestion. Five hundred and thirteen patients (90%) were admitted for intentional caustic ingestion. The median length of stay in ICU was 14.0 [4.0-31.0] days. In-hospital mortality occurred in 56 patients (9.8%). In multivariate analysis, age and simplified acute physiology score II were associated with in-hospital mortality age of 40-59 years [OR = 15.3 (2.0-115.3)], age of 60-79 years [OR = 23.6 (3.1-182.5)], and age > 80 years [OR = 37.0 (4.2-328.6)] and SAPS 2 score [OR = 1.0018 (1.003-1.033), p < 0.001]. During ICU stay, 423 complications (74%) were reported in 505 patients (89%). Infectious (244 (42.9%)), respiratory (207 (36.4%)), surgical 62 (10.9%), haemorrhagic (64 (11.2%)) and thrombo-embolic and (35 (6.2%)) complications were the most frequently reported during ICU stay., Conclusion: ICU admission for severe caustic ingestion is associated with 9.8% mortality and 74% complications. Age > 40 years and SAPS 2 score were independently associated with mortality., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.)

Background: Knowledge of the occurrence and outcome of admissions to Intensive Care Units (ICU) over time is important to inform healthcare services planning. This observational study aims at describing the activity of French ICUs between 2013 and 2019., Methods: Patient admission characteristics, organ dysfunction scores, therapies, ICU and hospital lengths of stay and case fatality were collected from the French National Hospital Database (population-based cohort). Logistic regression models were developed to investigate the association between age, sex, SAPS II, organ failure, and year of care on in-ICU case fatality., Findings: Among 1,594,801 ICU admissions, the yearly ICU admission increased from 3.3 to 3.5 per year per 1000 inhabitants (bed occupancy rate between 83.4 and 84.3%). The mean admission SAPS II was 42 ± 22, with a gradual annual increase. The median lengths of stay in ICU and in hospital were 3 (interquartile range (IQR) = [1-7]) and 11 days (IQR = [6-21]), respectively, with a progressive decrease over time. The in-ICU and hospital mortality case fatalities decreased from 18.0% to 17.1% and from 21.1% to 19.9% between 2013 and 2019, respectively. Male sex, age, SAPS II score, and the occurrence of any organ failure were associated with a higher case fatality rate. After adjustment on age, sex, SAPS II and organ failure, in-ICU case fatality decreased in 2019 as compared to 2013 (adjusted Odds Ratio = 0.87 [95% confidence interval, 0.85-0.89])., Interpretation: During the study, an increasing incidence of ICU admission was associated with higher severity of illness but lower in-ICU case fatality., (Copyright © 2023 Société française d'anesthésie et de réanimation (Sfar). Published by Elsevier Masson SAS. All rights reserved.)

Background: Real-time ultrasound (US) guidance facilitates central venous catheterization in intensive care unit (ICU). New magnetic needle-pilot devices could improve efficiency and safety of central venous catheterization. This simulation trial was aimed at comparing venipuncture with a new needle-pilot device to conventional US technique., Methods: In a prospective, randomized, simulation trial, 51 ICU physicians and residents cannulated the right axillary vein of a human torso mannequin with standard US guidance and with a needle-pilot system, in a randomized order. The primary outcome was the time from skin puncture to successful venous cannulation. The secondary outcomes were the number of skin punctures, the number of posterior wall puncture of the axillary vein, the number of arterial punctures, the number of needle redirections, the failure rate, and the operator comfort., Results: Time to successful cannulation was shorter with needle-pilot US-guided technique (22 s (interquartile range (IQR) = 16-42) vs 25 s (IQR = 19-128); median of difference (MOD) = -9 s (95%-confidence interval (CI) -5, -22), p  < 0.001). The rates of skin punctures, posterior wall puncture of axillary vein, and needle redirections were also lower ( p  < 0.01). Comfort was higher in needle-pilot US-guided group on a 11-points numeric scale (8 (IQR = 8-9) vs 6 (IQR = 6-8), p  < 0.001)., Conclusions: In a simulation model, US-guided axillary vein catheterization with a needle-pilot device was associated with a shorter time of successful cannulation and a decrease in numbers of skin punctures and complications. The results plea for investigating clinical performance of this new device., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Senescence is a key event in the impairment of adipose tissue (AT) function with obesity and aging but the underlying molecular and cellular players remain to be fully defined, particularly with respect to the human AT progenitors. We have found distinct profiles of senescent progenitors based on AT location between stroma from visceral versus subcutaneous AT. In addition to flow cytometry, we characterized the location differences with transcriptomic and proteomic approaches, uncovering the genes and developmental pathways that are underlying replicative senescence. We identified key components to include INBHA as well as SFRP4 and GREM1, antagonists for the WNT and BMP pathways, in the senescence-associated secretory phenotype and NOTCH3 in the senescence-associated intrinsic phenotype. Notch activation in AT progenitors inhibits adipogenesis and promotes myofibrogenesis independently of TGFβ. In addition, we demonstrate that NOTCH3 is enriched in the premyofibroblast progenitor subset, which preferentially accumulates in the visceral AT of patients with an early obesity trajectory. Herein, we reveal that NOTCH3 plays a role in the balance of progenitor fate determination preferring myofibrogenesis at the expense of adipogenesis. Progenitor NOTCH3 may constitute a tool to monitor replicative senescence and to limit AT dysfunction in obesity and aging., (© 2023 The Authors. Aging Cell published by Anatomical Society and John Wiley & Sons Ltd.)

Background: Ultrasound (US)-guided axillary vein (AV) catheterization has been considered as the preferred site of insertion to minimize catheter-related infections. Given its difficulty of realization, internal jugular vein (IJV) access remains, thus, the first choice of catheter insertion site. This descriptive study was aimed to assess the success and complication rates of in-plane short axis approach of IJV in the lower neck and the AV approach under US-guidance., Methods: In a prospective randomized controlled open-label pilot trial, all patients requiring central venous catheterization (CVC) in intensive care unit or operating room were randomly assigned to low IJV or AV groups. The primary objective was to estimate the overall success rate of both approaches. The secondary objectives were immediate complication rates, procedure durations, success rate after the first puncture, late complication rates (i.e., thrombosis, catheter colonization, and catheter-related infections), and nurse satisfaction regarding insertion site dressings., Results: One hundred and seventy-three out of two hundred and ten included patients were fully analyzed (90 and 83 in the IJV and AV approach groups, respectively). Overall success rates for IJV and AV sites were 96% (95% confidence interval (CI) [90-99]) and 89% (95% CI [81-94]) respectively. First puncture success rates were 90% and 80% respectively. The median overall procedure duration from US pre-procedural screening to guidewire insertion was 8 and 10 min in IJV and AV groups. Overall immediate complications rates for IJV and AV sites were 11.6% and 14.6%, respectively. Incidence of catheter colonization were 7.9% and 6.8% and catheter-related infection rate were 2.6% and 0%, respectively., Conclusion: In this pilot study, US-guided low IJV and AV approaches are safe and efficient techniques for CVC insertion associated with high success and low complications rates. Duration for guidewire insertion seemed to be shorter in the short axis in-plane IJV approach. It provides the basis for a future randomized trial comparing these two approaches., (© 2022 Wiley Periodicals LLC.)

Adipose tissue (AT) expansion either through hypertrophy or hyperplasia is determinant in the link between obesity and metabolic alteration. The present study aims to profile the unhealthy subcutaneous and visceral AT (SAT, VAT) expansion in obesity and in the outcomes of bariatric surgery (BS). The repartition of adipocytes according to diameter and the numbers of progenitor subtypes and immune cells of SAT and VAT from 161 obese patients were determined by cell imaging and flow cytometry, respectively. Associations with insulin resistance (IR) prior to BS as well as with the loss of excessive weight (EWL) and IR at 1 and 3 years post-BS were studied; prior to BS, SAT and VAT, unhealthy expansions are characterized by the accumulation of adipogenic progenitors and CD4+ T lymphocytes and by adipocyte hypertrophy and elevated macrophage numbers, respectively. Such SAT stromal profile and VAT adipocyte hypertrophy are associated with adverse BS outcomes. Finally, myofibrogenic progenitors are a common determinant of weight and IR trajectories post-BS; the study suggests that adipogenesis in SAT and adipocyte hypertrophy in VAT are common determinants of metabolic alterations with obesity and of the weight loss and metabolic response to bariatric surgery. The data open up new avenues to better understand and predict individual outcomes in response to changes in energy balance.

The amount and the distribution of body fat exhibit trajectories that are sex- and human species-specific and both are determinants for health. The enhanced accumulation of fat in the truncal part of the body as a risk factor for cardiovascular and metabolic diseases is well supported by epidemiological studies. In addition, a possible independent protective role of the gluteofemoral fat compartment and of the brown adipose tissue is emerging. The present narrative review summarizes the current knowledge on sexual dimorphism in fat depot amount and repartition and consequences on cardiometabolic and reproductive health. The drivers of the sex differences and fat depot repartition, considered to be the results of complex interactions between sex determination pathways determined by the sex chromosome composition, genetic variability, sex hormones and the environment, are discussed. Finally, the inter- and intra-depot heterogeneity in adipocytes and progenitors, emphasized recently by unbiased large-scale approaches, is highlighted.

Among the dietary amines present in foods and beverages, tyramine has been widely studied since its excessive ingestion can cause catecholamine release and hypertensive crisis. However, tyramine exerts other actions than depleting nerve endings: it activates subtypes of trace amine associated receptors (TAARs) and is oxidized by monoamine oxidases (MAO). Although we have recently described that tyramine is antilipolytic in human adipocytes, no clear evidence has been reported about its effects on glucose transport in the same cell model, while tyramine mimics various insulin-like effects in rodent fat cells, such as activation of glucose transport, lipogenesis, and adipogenesis. Our aim was therefore to characterize the effects of tyramine on glucose transport in human adipocytes. The uptake of the non-metabolizable analogue 2-deoxyglucose (2-DG) was explored in adipocytes from human subcutaneous abdominal adipose tissue obtained from women undergoing reconstructive surgery. Human insulin used as reference agent multiplied by three times the basal 2-DG uptake. Tyramine was ineffective from 0.01 to 10 µM and stimulatory at 100 µM-1 mM, without reaching the maximal effect of insulin. This partial insulin-like effect was not improved by vanadium and was impaired by MAO-A and MAO-B inhibitors. Contrarily to benzylamine, mainly oxidized by semicarbazide-sensitive amine oxidase (SSAO), tyramine activation of glucose transport was not inhibited by semicarbazide. Tyramine effect was not dependent on the Gi-coupled receptor activation but was impaired by antioxidants and reproduced by hydrogen peroxide. In all, the oxidation of high doses of tyramine, already reported to inhibit lipolysis in human fat cells, also partially mimic another effect of insulin in these cells, the glucose uptake activation. Thus, other MAO substrates are potentially able to modulate carbohydrate metabolism., (© 2021. The Author(s) under exclusive licence to University of Navarra.)

Background: When combined with vanadium salts, catecholamines strongly activate glucose uptake in rat and mouse adipocytes., Aim: To test whether catecholamines activate glucose transport in human adipocytes., Methods: The uptake of 2-deoxyglucose (2-DG) was measured in adipocytes isolated from pieces of abdominal subcutaneous tissue removed from women undergoing reconstructive surgery. Pharmacological approaches with amine oxidase inhibitors, adrenoreceptor agonists and antioxidants were performed to unravel the mechanisms of action of noradrenaline or adrenaline (also named epinephrine)., Results: In human adipocytes, 45-min incubation with 100 µmol/L adrenaline or noradrenaline activated 2-DG uptake up to more than one-third of the maximal response to insulin. This stimulation was not reproduced with millimolar doses of dopamine or serotonin and was not enhanced by addition of vanadate to the incubation medium. Among various natural amines and adrenergic agonists tested, no other molecule was more efficient than adrenaline and noradrenaline in stimulating 2-DG uptake. The effect of the catecholamines was not impaired by pargyline and semicarbazide, contrarily to that of benzylamine or methylamine, which are recognized substrates of semicarbazide-sensitive amine oxidase. Hydrogen peroxide at 1 mmol/L activated hexose uptake but not pyrocatechol or benzoquinone, and only the former was potentiated by vanadate. Catalase and the phosphoinositide 3-kinase inhibitor wortmannin inhibited adrenaline-induced activation of 2-DG uptake., Conclusion: High doses of catecholamines exert insulin-like actions on glucose transport in human adipocytes. At submillimolar doses, vanadium did not enhance this catecholamine activation of glucose transport. Consequently, this dismantles our previous suggestion to combine the metal ion with catecholamines to improve the benefit/risk ratio of vanadium-based antidiabetic approaches., Competing Interests: Conflict-of-interest statement: The authors declare no competing financial interests., (©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.)

Context: Adipose tissue (AT) transcriptome studies provide holistic pictures of adaptation to weight and related bioclinical settings changes., Objective: To implement AT gene expression profiling and investigate the link between changes in bioclinical parameters and AT gene expression during 3 steps of a 2-phase dietary intervention (DI)., Methods: AT transcriptome profiling was obtained from sequencing 1051 samples, corresponding to 556 distinct individuals enrolled in a weight loss intervention (8-week low-calorie diet (LCD) at 800 kcal/day) followed with a 6-month ad libitum randomized DI. Transcriptome profiles obtained with QuantSeq sequencing were benchmarked against Illumina RNAseq. Reverse transcription quantitative polymerase chain reaction was used to further confirm associations. Cell specificity was assessed using freshly isolated cells and THP-1 cell line., Results: During LCD, 5 modules were found, of which 3 included at least 1 bioclinical variable. Change in body mass index (BMI) connected with changes in mRNA level of genes with inflammatory response signature. In this module, change in BMI was negatively associated with changes in expression of genes encoding secreted protein (GDF15, CCL3, and SPP1). Through all phases of the DI, change in GDF15 was connected to changes in SPP1, CCL3, LIPA and CD68. Further characterization showed that these genes were specific to macrophages (with LIPA, CD68 and GDF15 expressed in anti-inflammatory macrophages) and GDF15 also expressed in preadipocytes., Conclusion: Network analyses identified a novel AT feature with GDF15 upregulated with calorie restriction induced weight loss, concomitantly to macrophage markers. In AT, GDF15 was expressed in preadipocytes and macrophages where it was a hallmark of anti-inflammatory cells., (© The Author(s) 2021. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The activation of thermogenesis in adipose tissue has emerged as an important target for the development of novel anti-obesity therapies. Using multi-well isothermal microcalorimetry, we have demonstrated that mature murine brown and brite adipocytes produce quantifiable heat upon β 3 -AR stimulation, independently of any anaerobic mechanisms. Additionally, in brite adipocytes lacking UCP1 protein, β 3 -AR stimulation still induces heat production, albeit to a much lower extent than in their wildtype counterparts, suggesting that UCP1 is an essential component of adrenergic induced thermogenesis in murine brite adipocytes exvivo. Similarly, we could observe an increase in heat production in human-derived adipocytes (hMADS) upon β-AR stimulation. Collectively, these results establish the use of isothermal microcalorimetry as a sensitive and accurate technique for measuring thermogenic responses in intact mature brite adipocytes from murine and human origin., (© 2021. The Author(s).)

Caffeine is a plant alkaloid present in food and beverages consumed worldwide. It has high lipid solubility with recognized actions in the central nervous system and in peripheral tissues, notably the adipose depots. However, the literature is scant regarding caffeine's influence on adipocyte functions other than lipolysis, such as glucose incorporation into lipids (lipogenesis) and amine oxidation. The objective of this study was to explore the direct effects of caffeine and of isobutylmethylxanthine (IBMX) on these adipocyte functions. Glucose transport into fat cells freshly isolated from mice, rats, or humans was monitored by determining [ 3 H]-2-deoxyglucose (2-DG) uptake, while the incorporation of radiolabeled glucose into cell lipids was used as an index of lipogenic activity. Oxidation of benzylamine by primary amine oxidase (PrAO) was inhibited by increasing doses of caffeine in human adipose tissue preparations with an inhibition constant (Ki) in the millimolar range. Caffeine inhibited basal and insulin-stimulated glucose transport as well as lipogenesis in rodent adipose cells. The antilipogenic action of caffeine was also observed in adipocytes from mice genetically invalidated for PrAO activity, indicating that PrAO activity was not required for lipogenesis inhibition. These caffeine inhibitory properties were extended to human adipocytes: relative to basal 2-DG uptake, set at 1.0 ± 0.2 for 6 individuals, 0.1 mM caffeine tended to reduce uptake to 0.83 ± 0.08. Insulin increased uptake by 3.86 ± 1.11 fold when tested alone at 100 nM, and by 3.21 ± 0.80 when combined with caffeine. Our results reinforce the recommendation of caffeine's potential in the treatment or prevention of obesity complications.

Functional telomeres in yeast lacking telomerase can be restored by rare Rad51- or Rad59-dependent recombination events that lead to type I and type II survivors, respectively. We previously proposed that polySUMOylation of proteins and the SUMO-targeted ubiquitin ligase Slx5-Slx8 are key factors in type II recombination. Here, we show that SUMOylation of Rad52 favors the formation of type I survivors. Conversely, preventing Rad52 SUMOylation partially bypasses the requirement of Slx5-Slx8 for type II recombination. We further report that SUMO-dependent proteasomal degradation favors type II recombination. Finally, inactivation of Rad59, but not Rad51, impairs the relocation of eroded telomeres to the Nuclear Pore complexes (NPCs). We propose that Rad59 cooperates with non-SUMOylated Rad52 to promote type II recombination at NPCs, resulting in the emergence of more robust survivors akin to ALT cancer cells. Finally, neither Rad59 nor Rad51 is required by itself for the survival of established type II survivors., Competing Interests: The authors declare no competing interests., (© 2021 The Author(s).)

Cold- and diet-induced recruitment of brown adipose tissue (BAT) and the browning of white adipose tissue (WAT) are dynamic processes, and the recruited state attained is a state of dynamic equilibrium, demanding continuous stimulation to be maintained. An involvement of macrophages, classical proinflammatory (M1) or alternatively activated anti-inflammatory (M2), is presently discussed as being an integral part of these processes. If these macrophages play a mediatory role in the recruitment process, such an involvement would have to be maintained in the recruited state. We have, therefore, investigated whether the recruited state of these tissues is associated with macrophage accretion or attrition. We found no correlation (positive or negative) between total UCP1 mRNA levels (as a measure of recruitment) and proinflammatory macrophages in any adipose depot. We found that in young chow-fed mice, cold-induced recruitment correlated with accretion of anti-inflammatory macrophages; however, such a correlation was not seen when cold-induced recruitment was studied in diet-induced obese mice. Furthermore, the anti-inflammatory macrophage accretion was mediated via β 1 /β 2 -adrenergic receptors; yet, in their absence, and thus in the absence of macrophage accretion, recruitment proceeded normally. We thus conclude that the classical recruited state in BAT and inguinal (brite/beige) WAT is not paralleled by macrophage accretion or attrition. Our results make mediatory roles for macrophages in the recruitment process less likely. NEW & NOTEWORTHY A regulatory or mediatory role-positive or negative-for macrophages in the recruitment of brown adipose tissue is presently discussed. As the recruited state in the tissue is a dynamic process, maintenance of the recruited state would need persistent alterations in macrophage complement. Contrary to this expectation, we demonstrate here an absence of alterations in macrophage complement in thermogenically recruited brown-or brite/beige-adipose tissues. Macrophage regulation of thermogenic capacity is thus less likely.

We hypothesized that skeletal muscle contraction produces a cellular stress signal, triggering adipose tissue lipolysis to sustain fuel availability during exercise. The present study aimed at identifying exercise-regulated myokines, also known as exerkines, able to promote lipolysis. Human primary myotubes from lean healthy volunteers were submitted to electrical pulse stimulation (EPS) to mimic either acute intense or chronic moderate exercise. Conditioned media (CM) experiments with human adipocytes were performed. CM and human plasma samples were analyzed using unbiased proteomic screening and/or ELISA. Real-time qPCR was performed in cultured myotubes and muscle biopsy samples. CM from both acute intense and chronic moderate exercise increased basal lipolysis in human adipocytes. Growth and differentiation factor 15 (GDF15) gene expression and secretion increased rapidly upon skeletal muscle contraction. GDF15 protein was upregulated in CM from both acute and chronic exercise-stimulated myotubes. We further showed that physiological concentrations of recombinant GDF15 protein increased lipolysis in human adipose tissue, while blocking GDF15 with a neutralizing antibody abrogated EPS CM-mediated lipolysis. We herein provide the first evidence to our knowledge that GDF15 is a potentially novel exerkine produced by skeletal muscle contraction and able to target human adipose tissue to promote lipolysis.

Treatment with several antipsychotic drugs exhibits a tendency to induce weight gain and diabetic complications. The proposed mechanisms by which the atypical antipsychotic drug olanzapine increases body weight include central dysregulations leading to hyperphagia and direct peripheral impairment of fat cell lipolysis. Several investigations have reproduced in vitro direct actions of antipsychotics on rodent adipocytes, cultured preadipocytes, or human adipose tissue-derived stem cells. However, to our knowledge, no such direct action has been described in human mature adipocytes. The aim of the present study was to compare in human adipocytes the putative direct alterations of lipolysis by antipsychotics (haloperidol, olanzapine, ziprazidone, risperidone), antidepressants (pargyline, phenelzine), or anxiolytics (opipramol). Lipolytic responses to the tested drugs, and to recognized lipolytic (e.g., isoprenaline) or antilipolytic agents (e.g., insulin) were determined, together with glucose transport and amine oxidase activities in abdominal subcutaneous adipocytes from individuals undergoing plastic surgery. None of the tested drugs were lipolytic. Surprisingly, only opipramol exhibited substantial antilipolytic properties in the micromolar to millimolar range. An opipramol antilipolytic effect was evident against isoprenaline-, forskolin-, or atrial natriuretic peptide-stimulated lipolysis. Opipramol did not impair insulin activation of glucose transport but inhibited monoamine oxidase (MAO) activity to the same extent as antidepressants recognized as MAO inhibitors (pargyline, harmine, or phenelzine), whereas antipsychotics were inefficient. Considering its unique properties, opipramol, which is not associated with weight gain in treated patients, is a good candidate for drug repurposing because it limits exaggerated lipolysis, prevents hydrogen peroxide release by amine oxidases in adipocytes, and is thereby of potential use to limit lipotoxicity and oxidative stress, two deleterious complications of diabetes and obesity., Competing Interests: The authors declare that they have no conflict of interest for any aspect of this research.

Background : Methylamine, a natural soluble amine present in foods, is known to be a substrate of primary amine oxidase (PrAO) widely expressed in animal tissues. Methylamine has been reported to activate glucose transport in fat cells and to facilitate glucose disposal in rabbits but the interests and limits of such insulin-mimicking actions have not been further explored. This work aimed to perform a preclinical study of the inter-individual variations of these biological properties to study the putative link between PrAO activity and insulin resistance. Methods : Methylamine was tested on human adipocyte preparations and in rabbit pancreatic islets to determine its influence on glucose uptake and insulin release, respectively. PrAO activity and related responses were determined in adipose tissues obtained from two cohorts of non-obese and obese women. Results : Adipose tissue PrAO activity was negatively correlated with insulin resistance in high-risk obese women. PrAO-dependent activation of glucose uptake was negatively correlated with body mass index and reflected the decrease of insulin responsiveness of human fat cells with increasing obesity. Methylamine exhibited antilipolytic properties in adipocytes but was unable to directly activate insulin secretion in isolated pancreatic islets. Conclusions : PrAO activation by its substrates, e.g., methylamine, increases glucose utilization in human adipocytes in a manner that is linked to insulin responsiveness. Methylamine/PrAO interaction can therefore contribute to adipose tissue enlargement but should be considered as potentially useful for diabetes prevention since it could limit lipotoxicity and facilitate glucose handling, at the expense of favoring healthy fat accumulation.

Various amino acid (AA) metabolites are used as supplements to facilitate metabolic control and enhance responsiveness of insulin-sensitive tissues. β-hydroxy-β-methylbutyrate (HMB) is a leucine metabolite proposed to prevent muscle wasting and to mitigate insulin resistance. Taurine, commonly added to energizing drinks, is a metabolite of methionine and cysteine present in bile juice, and proposed to be involved in lipid digestion and to be pro-lipolytic in adipocytes. N-methyltyramine (NMT) is a phenylalanine metabolite found in orange juices at 0.1-3 ppm while its effects on lipid mobilization remain controversial. Here, the putative lipolytic effects of these AA metabolites were studied and it was tested whether they could enhance insulin antilipolytic response in adipocytes. Release of glycerol and non-esterified fatty acids (NEFAs) was measured after a 2-h incubation of adipocytes obtained from control and diet-induced obese mice or from obese patients. In mouse, none of the tested AA derivatives was lipolytic from 1 μM to 1 mM. These compounds did not improve insulin antilipolytic effect or isoprenaline lipolytic action, except for 1 mM NMT that impaired triacylglycerol breakdown in obese mice. In human adipocytes, HMB and taurine were not lipolytic, while NMT weakly activated glycerol and NEFA release at 1 mM. However, 100 μM NMT impaired isoprenaline-stimulated lipolysis in a manner that was hardly added to insulin antilipolytic effect. Since none of these AA derivatives acutely helped or replaced insulin antilipolytic effect in adipocytes, the present in vitro observations do not support their proposed insulin-sensitizing properties. Moreover, NMT, HMB, and taurine were not notably lipolytic.

An excess of glucocorticoids leads to the development of obesity in both mice and humans, but the mechanism for this is unknown. Here, we determine the extent to which decreased BAT thermogenic capacity (as a result of glucocorticoid treatment) contributes to the development of obesity. Contrary to previous suggestions, we show that only in mice housed at thermoneutrality (30°C) does corticosterone treatment reduce total BAT UCP1 protein. This reduction is reflected in reduced brown adipocyte cellular and mitochondrial UCP1-dependent respiration. However, glucocorticoid-induced obesity develops to the same extent in animals housed at 21°C and 30°C, whereas total BAT UCP1 protein levels differ 100-fold between the two groups. In corticosterone-treated wild-type and UCP1 knockout mice housed at 30°C, obesity also develops to the same extent. Thus, our results demonstrate that the development of glucocorticoid-induced obesity is not caused by a decreased UCP1-dependent thermogenic capacity., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Two classes of amine oxidases are found in mammals: those with a flavin adenine dinucleotide as a cofactor, such as monoamine oxidases (MAO) and lysine-specific demethylases (LSD), and those with copper as a cofactor, including copper-containing amine oxidases (AOC) and lysyl oxidases (LOX). All are expressed in adipose tissue, including a semicarbazide-sensitive amine oxidase/vascular adhesion protein-1 (SSAO/VAP-1) strongly present on the adipocyte surface. Methods: Previously, irreversible MAO inhibitors have been reported to limit food intake and/or fat extension in rodents; however, their use for the treatment of depressed patients has not revealed a clear anti-obesity action. Semicarbazide and other molecules inhibiting SSAO/VAP-1 also reduce adiposity in obese rodents. Results: Recently, a LOX inhibitor and a subtype-selective MAO inhibitor have been shown to limit fattening in high-fat diet-fed rats. Phenelzine, which inhibits MAO and AOC, limits adipogenesis in cultured preadipocytes and impairs lipogenesis in mature adipocytes. When tested in rats or mice, phenelzine reduces food intake and/or fat accumulation without cardiac adverse effects. Novel amine oxidase inhibitors have been recently characterized in a quest for promising anti-inflammatory or anti-cancer approaches; however, their capacity to mitigate obesity has not been studied so far. Conclusions: The present review of the diverse effects of amine oxidase inhibitors impairing adipocyte differentiation or limiting excessive fat accumulation indicates that further studies are needed to reveal their potential anti-obesity properties.

Phenolic compounds are among the most investigated herbal remedies, as is especially the case for resveratrol. Many reports have shown its anti-aging properties and the ability to reduce obesity and diabetes induced by high-fat diet in mice. However, such beneficial effects hardly translate from animal models to humans. The scientific community has therefore tested whether other plant phenolic compounds may surpass the effects of resveratrol. In this regard, it has been reported that piceatannol reproduces in rodents the anti-obesity actions of its parent polyphenol. However, the capacity of piceatannol to inhibit adipocyte differentiation in humans has not been characterized so far. Here, we investigated whether piceatannol was antiadipogenic and antilipogenic in human preadipocytes. Human mesenchymal stem cells (hMSC), isolated from adipose tissues of lean and obese individuals, were differentiated into mature adipocytes with or without piceatannol, and their functions were explored. Fifty μM of piceatannol deeply limited synthesis/accumulation of lipids in both murine and hMSC-derived adipocytes. Interestingly, this phenomenon occurred irrespective of being added at the earlier or later stages of adipocyte differentiation. Moreover, piceatannol lowered glucose transport into adipocytes and decreased the expression of key elements of the lipogenic pathway (PPARγ, FAS, and GLUT4). Thus, the confirmation of the antiadipogenic properties of piceatanol in vitro warrants the realization of clinical studies for the application of this compound in the treatment of the metabolic complications associated with obesity., Competing Interests: The authors declare that there are no conflicts of interest.

Brown and brite/beige adipocytes are attractive therapeutic targets to treat metabolic diseases. To maximally utilize their functional potential, further understanding is required about their identities and their functional differences. Recent studies with β 3 -adrenergic receptor knockout mice reported that brite/beige adipocytes, but not classical brown adipocytes, require the β 3 -adrenergic receptor for cold-induced transcriptional activation of thermogenic genes. We aimed to further characterize this requirement of the β 3 -adrenergic receptor as a functional distinction between classical brown and brite/beige adipocytes. However, when comparing wild-type and β 3 -adrenergic receptor knockout mice, we observed no differences in cold-induced thermogenic gene expression ( Ucp1 , Pgc1a , Dio2 , and Cidea ) in brown or white (brite/beige) adipose tissues. Irrespective of the duration of the cold exposure or the sex of the mice, we observed no effect of the absence of the β 3 -adrenergic receptor. Experiments with the β 3 -adrenergic receptor agonist CL-316,243 verified the functional absence of β 3 -adrenergic signaling in these knockout mice. The β 3 -adrenergic receptor knockout model in the present study was maintained on a FVB/N background, whereas earlier reports used C57BL/6 and 129Sv mice. Thus our data imply background-dependent differences in adrenergic signaling mechanisms in response to cold exposure. Nonetheless, the present data indicate that the β 3 -adrenergic receptor is dispensable for cold-induced transcriptional activation in both classical brown and, as opposed to earlier studies, brite/beige cells., (Copyright © 2017 the American Physiological Society.)

We aimed to investigate the potential anti-emetic and anti-nausea properties of targeting the cannabinoid 2 (CB2) receptor. We investigated the effect of the selective CB2 agonist, HU-308, on lithium chloride- (LiCl) induced vomiting in Suncus murinus (S. murinus) and conditioned gaping (nausea-induced behaviour) in rats. Additionally, we determined whether these effects could be prevented by pretreatment with AM630 (a selective CB2 receptor antagonist/inverse agonist). In S. murinus, HU-308 (2.5, 5mg/kg, i.p.) reduced, but did not completely block, LiCl-induced vomiting; an effect that was prevented with AM630. In rats, HU-308 (5mg/kg, i.p.) suppressed, but did not completely block, LiCl-induced conditioned gaping to a flavour; an effect that was prevented by AM630. These findings are the first to demonstrate the ability of a selective CB2 receptor agonist to reduce nausea in animal models, indicating that targeting the CB2 receptor may be an effective strategy, devoid of psychoactive effects, for managing toxin-induced nausea and vomiting., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Homologous recombination (HR) is essential for maintenance of genome stability through double-strand break (DSB) repair, but at the same time HR can lead to loss of heterozygosity and uncontrolled recombination can be genotoxic. The post-translational modification by SUMO (small ubiquitin-like modifier) has been shown to modulate recombination, but the exact mechanism of this regulation remains unclear. Here we show that SUMOylation stabilizes the interaction between the recombination mediator Rad52 and its paralogue Rad59 in Saccharomyces cerevisiae. Although Rad59 SUMOylation is not required for survival after genotoxic stress, it affects the outcome of recombination to promote conservative DNA repair. In some genetic assays, Rad52 and Rad59 SUMOylation act synergistically. Collectively, our data indicate that the described SUMO modifications affect the balance between conservative and non-conservative mechanisms of HR., Competing Interests: The authors declare that there are no conflicts of interest., (Copyright © 2016 Elsevier B.V. All rights reserved.)

In budding yeast, inactivation of telomerase and ensuing telomere erosion cause relocalization of telomeres to nuclear pore complexes (NPCs). However, neither the mechanism of such relocalization nor its significance are understood. We report that proteins bound to eroded telomeres are recognized by the SUMO (small ubiquitin-like modifier)-targeted ubiquitin ligase (STUbL) Slx5-Slx8 and become increasingly SUMOylated. Recruitment of Slx5-Slx8 to eroded telomeres facilitates telomere relocalization to NPCs and type II telomere recombination, a counterpart of mammalian alternative lengthening of telomeres (ALT). Moreover, artificial tethering of a telomere to a NPC promotes type II telomere recombination but cannot bypass the lack of Slx5-Slx8 in this process. Together, our results indicate that SUMOylation positively contributes to telomere relocalization to the NPC, where poly-SUMOylated proteins that accumulated over time have to be removed. We propose that STUbL-dependent relocalization of telomeres to NPCs constitutes a pathway in which excessively SUMOylated proteins are removed from "congested" intermediates to ensure unconventional recombination., (Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.)