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Introduction: There is a lack of evidence that the benefits of screening for atrial fibrillation (AF) outweigh the harms. Following the completion of the Screening for Atrial Fibrillation with ECG to Reduce stroke (SAFER) pilot trial, the aim of the main SAFER trial is to establish whether population screening for AF reduces incidence of stroke risk., Methods and Analysis: Approximately 82 000 people aged 70 years and over and not on oral anticoagulation are being recruited from general practices in England. Patients on the palliative care register or residents in a nursing home are excluded. Eligible people are identified using electronic patient records from general practices and sent an invitation and consent form to participate by post. Consenting participants are randomised at a ratio of 2:1 (control:intervention) with clustering by household. Those randomised to the intervention arm are sent an information leaflet inviting them to participate in screening, which involves use of a handheld single-lead ECG four times a day for 3 weeks. ECG traces identified by an algorithm as possible AF are reviewed by cardiologists. Participants with AF are seen by a general practitioner for consideration of anticoagulation. The primary outcome is stroke. Major secondary outcomes are: death, major bleeding and cardiovascular events. Follow-up will be via electronic health records for an average of 4 years. The primary analysis will be by intention-to-treat using time-to-event modelling. Results from this trial will be combined with follow-up data from the cluster-randomised pilot trial by fixed-effects meta-analysis., Ethics and Dissemination: The London-Central National Health Service Research Ethics Committee (19/LO/1597) provided ethical approval. Dissemination will include public-friendly summaries, reports and engagement with the UK National Screening Committee., Trial Registration Number: ISRCTN72104369., Competing Interests: Competing interests: JM has performed consultancy work for BMS/Pfizer and Omron. FDRH reports occasional consultancy for BMS/Pfizer, Bayer and BI over the past 5 years. NA is a member of the UK National Screening Committee. MC and MS are employed by AstraZeneca, but at the time of involvement with the trial were employed by universities (King's College London and University of Leicester, respectively), for which they still hold honorary contracts. RJM’s employer, the University of Oxford, receives consultancy and licensing payments from Omron and Sensyne for BP telemonitoring interventions. GYHL is a consultant and speaker for BMS/Pfizer, Boehringer Ingelheim, Daiichi-Sankyo and Anthos. No fees are received personally. SJG has received honoraria from AstraZeneca for lectures at postgraduate educational meetings for primary care teams about type 2 diabetes. BF has received speaker fees, honoraria and non-financial support from BMS and Pfizer Alliance; grants to the institution for investigator-initiated studies from BMS and Pfizer Alliance; and loan devices for investigator-initiated studies from Alivecor, all were unrelated to the present trial but related to screening for AF., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY. Published by BMJ.)

In addition to its antiatherogenic role, HDL reportedly modulates energy metabolism at the whole-body level. HDL functionality is associated with its structure and composition, and functional activities can differ between HDL subclasses. Therefore, we studied if HDL 2 and HDL 3 , the two major HDL subclasses, are able to modulate energy metabolism of skeletal muscle cells. Differentiated mouse and primary human skeletal muscle myotubes were used to investigate the influences of human HDL 2 and HDL 3 on glucose and fatty uptake and oxidation. HDL-induced changes in lipid distribution and mRNA expression of genes related to energy substrate metabolism, mitochondrial function, and HDL receptors were studied with human myotubes. Additionally, we examined the effects of apoA-I and discoidal, reconstituted HDL particles on substrate metabolism. In mouse myotubes, HDL subclasses strongly enhanced glycolysis upon high and low glucose concentrations. HDL 3 caused a minor increase in ATP-linked respiration upon glucose conditioning but HDL 2 improved complex I-mediated mitochondrial respiration upon fatty acid treatment. In human myotubes, glucose metabolism was attenuated but fatty acid uptake and oxidation were markedly increased by both HDL subclasses, which also increased mRNA expression of genes related to fatty acid metabolism and HDL receptors. Finally, both HDL subclasses induced incorporation of oleic acid into different lipid classes. These results, demonstrating that HDL subclasses enhance fatty acid oxidation in human myotubes but improve anaerobic metabolism in mouse myotubes, support the role of HDL as a circulating modulator of energy metabolism. Exact mechanisms and components of HDL causing the change, require further investigation., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Parenteral (intravenous) nutrition is lifesaving for patients with intestinal failure, but long-term use of parenteral nutrition often leads to liver disease. SEFA-6179 is a synthetic medium-chain fatty acid analogue designed to target multiple fatty acid receptors regulating metabolic and inflammatory pathways. We hypothesized that SEFA-6179 would prevent hepatosteatosis and lipotoxicity in a murine model of parenteral nutrition-induced hepatosteatosis., Methods: Two in vivo experiments were conducted. In the first experiment, six-week-old male mice were provided an ad lib fat-free high carbohydrate diet (HCD) for 19 days with orogastric gavage of either fish oil, medium-chain triglycerides, or SEFA-6179 at a low (0.3mmol/kg) or high dose (0.6mmol/kg). In the second experiment, six-week-old mice were provided an ad lib fat-free high carbohydrate diet for 19 days with every other day tail vein injection of saline, soybean oil lipid emulsion, or fish oil lipid emulsion. Mice then received every other day orogastric gavage of medium-chain triglyceride vehicle or SEFA-6179 (0.6mmol/kg). Hepatosteatosis was assessed by a blinded pathologist using an established rodent steatosis score. Hepatic lipid metabolites were assessed using ultra-high-performance liquid chromatography-mass spectrometry. Effects of SEFA-6179 on fatty acid oxidation, lipogenesis, and fatty acid uptake in human liver cells were assessed in vitro., Results: In the first experiment, mice receiving the HCD with either saline or medium-chain triglyceride treatment developed macrovesicular steatosis, while mice receiving fish oil or SEFA-6179 retained normal liver histology. In the second experiment, mice receiving a high carbohydrate diet with intravenous saline or soybean oil lipid emulsion, along with medium chain triglyceride vehicle treatment, developed macrovescular steatosis. Treatment with SEFA-6179 prevented steatosis. In each experiment, SEFA-6179 treatment decreased arachidonic acid metabolites as well as key molecules (diacylglycerol, ceramides) involved in lipotoxicity. SEFA-6179 increased both β- and complete fatty oxidation in human liver cells, while having no impact on lipogenesis or fatty acid uptake., Conclusions: SEFA-6179 treatment prevented hepatosteatosis and decreased toxic lipid metabolites in a murine model of parenteral nutrition-induced hepatosteatosis. An increase in both β- and complete hepatic fatty acid oxidation may underlie the reduction in steatosis., Competing Interests: This study was primarily funded via a sponsored research agreement with NorthSea Therapeutics. SEFA-6179 is a drug under clinical development by NorthSea Therapeutics for intestinal failure-associated liver disease. Dr. Fraser is the Chief Scientific Officer of NorthSea Therapeutics. Drs. Puder and Gura are external consultants for Northsea Therapeutics. The study was designed in consultation with NorthSea Therapeutics, but final study design decisions were made by Dr. Puder. NorthSea Therapeutics and Dr. Fraser were not involved in the collection, analysis, or interpretation of data. These competing interests do not alter the adherence to all PLOS ONE policies on sharing data and materials., (Copyright: © 2023 Cho et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

The roles of DGAT1 and DGAT2 in lipid metabolism and insulin responsiveness of human skeletal muscle were studied using cryosections and myotubes prepared from muscle biopsies from control, athlete, and impaired glucose regulation (IGR) cohorts of men. The previously observed increases in intramuscular triacylglycerol (IMTG) in athletes and IGR were shown to be related to an increase in lipid droplet (LD) area in type I fibers in athletes but, conversely, in type II fibers in IGR subjects. Specific inhibition of both diacylglycerol acyltransferase (DGAT) 1 and 2 decreased fatty acid (FA) uptake by myotubes, whereas only DGAT2 inhibition also decreased fatty acid oxidation. Fatty acid uptake in myotubes was negatively correlated with the lactate thresholds of the respective donors. DGAT2 inhibition lowered acetate uptake and oxidation in myotubes from all cohorts whereas DGAT1 inhibition had no effect. A positive correlation between acetate oxidation in myotubes and resting metabolic rate (RMR) from fatty acid oxidation in vivo was observed. Myotubes from athletes and IGR had higher rates of de novo lipogenesis from acetate that were normalized by DGAT2 inhibition. Moreover, DGAT2 inhibition in myotubes also resulted in increased insulin-induced Akt phosphorylation. The differential effects of DGAT1 and DGAT2 inhibition suggest that the specialized role of DGAT2 in esterifying nascent diacylglycerols and de novo synthesized FA is associated with synthesis of a pool of triacylglycerol, which upon hydrolysis results in effectors that promote mitochondrial fatty acid oxidation but decrease insulin signaling in skeletal muscle cells., (© 2023 The Authors. The FASEB Journal published by Wiley Periodicals LLC on behalf of Federation of American Societies for Experimental Biology.)

Background: As a result of new technologies, atrial fibrillation (AF) is more likely to be diagnosed in people aged <65 years., Aim: To investigate the risk of someone diagnosed with AF aged <65 years developing an indication for anticoagulation before they reach 65 years., Design and Setting: Population-based cohort study of patients from English practices using the Clinical Practice Research Datalink, a primary care database of electronic medical records., Method: The study included patients aged <65 years newly diagnosed with AF. The CHA 2 DS 2 -VASc score was derived at time of diagnosis based on patients' medical records. Patients not eligible for anticoagulation were followed up until they became eligible or turned 65 years old. The primary outcome of interest was development of a risk factor for stroke in AF., Results: Among 18 178 patients aged <65 years diagnosed with AF, 9188 (50.5%) were eligible for anticoagulation at the time of diagnosis. Among the 8990 patients not eligible for anticoagulation, 1688 (18.8%) developed a risk factor during follow-up before reaching 65 years of age or leaving the cohort for other reasons, at a rate of 6.1 per 100 patient-years. Hypertension and heart failure were the most common risk factors to occur, with rates of 2.65 (95% CI = 2.47 to 2.84) and 1.58 (95% CI = 1.45 to 1.72) per 100 patient-years, respectively. The rate of new diabetes was 0.95 (95% CI = 0.85 to 1.06) per 100 patient-years., Conclusion: People aged <65 years with AF are at higher risk of developing hypertension, heart failure, and diabetes than the general population, so may warrant regular review to identify new occurrence of such risk factors., (© The Authors.)

Background: There is no clear guidance on how to implement opportunistic atrial fibrillation (AF) screening in daily clinical practice., Objectives: This study evaluated the perception of general practitioners (GPs) about value and practicalities of implementing screening for AF, focusing on opportunistic single-time point screening with a single-lead electrocardiogram (ECG) device., Methods: A descriptive cross-sectional study was conducted with a survey developed to assess overall perception concerning AF screening, feasibility of opportunistic single-lead ECG screening and implementation requirements and barriers., Results: A total of 659 responses were collected (36.1% Eastern, 33.4% Western, 12.1% Southern, 10.0% Northern Europe, 8.3% United Kingdom & Ireland). The perceived need for standardized AF screening was rated as 82.7 on a scale from 0 to 100. The vast majority (88.0%) indicated no AF screening program is established in their region. Three out of four GPs (72.1%, lowest in Eastern and Southern Europe) were equipped with a 12-lead ECG, while a single-lead ECG was less common (10.8%, highest in United Kingdom & Ireland). Three in five GPs (59.3%) feel confident ruling out AF on a single-lead ECG strip. Assistance through more education (28.7%) and a tele-healthcare service offering advice on ambiguous tracings (25.2%) would be helpful. Preferred strategies to overcome barriers like insufficient (qualified) staff, included integrating AF screening with other healthcare programs (24.9%) and algorithms to identify patients most suitable for AF screening (24.3%)., Conclusion: GPs perceive a strong need for a standardized AF screening approach. Additional resources may be required to have it widely adopted into clinical practice., Competing Interests: BF has received grants to the institution for investigator-initiated studies from the BMS-Pfizer Alliance, personal fees and nonfinancial support from BMS-Pfizer Alliance and Pfizer, and loan devices from AliveCor. HH did receive personal lecture and consultancy fees from Abbott, Biotronik, Daiichi-Sankyo, Pfizer-BMS, Medscape, and Springer Healthcare Ltd. He received unconditional research grants through the University of Antwerp and/or the University of Hasselt from Abbott, Bayer, Biotronik, Biosense-Webster, Boston-Scientific, Boehringer-Ingelheim, Daicchi-Sankyo, Fibricheck/Qompium, Medtronic, and Pfizer-BMS. HP received speaker fees from Bayer, Pfizer, Boehringer Ingelheim and Daiichi-Sankyo. LN and CH hold an investigator initiated grant from Daiichi Sankyo (£75,000). MF received speaker fees from Pfizer Poland and Boehringer Ingelheim Poland. RS has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program under the grant agreement No 648131, from the European Union’s Horizon 2020 research and innovation program under the grant agreement No 847770 (AFFECT-EU) and German Center for Cardiovascular Research (DZHK e.V.) (81Z1710103 and 81Z0710114); German Ministry of Research and Education (BMBF 01ZX1408A) and ERACoSysMed3 (031L0239). RS has received lecture fees and advisory board fees from BMS/Pfizer outside this work. HW was employed by Pfizer Pharma GmbH, Berlin, Germany. MH was employed by StopAfib.org, Dallas, TX, United States. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Vermunicht, Grecu, Deharo, Buckley, Palà, Mairesse, Farkowski, Bergonti, Pürerfellner, Hanson, Neubeck, Freedman, Witt, Hills, Lund, Giskes, Engler, Schnabel, Heidbuchel, Desteghe and for the AFFECT-EU investigators.)

Adipose tissue is one of the main regulative sites for energy metabolism. Excess lipid storage and expansion of white adipose tissue (WAT) is the primary contributor to obesity, a strong predisposing factor for development of insulin resistance. Sentrin-specific protease (SENP) 2 has been shown to play a role in metabolism in murine fat and skeletal muscle cells, and we have previously demonstrated its role in energy metabolism of human skeletal muscle cells. In the present work, we have investigated the impact of SENP2 on fatty acid and glucose metabolism in primary human fat cells by using cultured primary human adipocytes to knock down the SENP2 gene. Glucose uptake and oxidation, as well as accumulation and distribution of oleic acid into complex lipids were decreased, while oleic acid oxidation was increased in SENP2-knockdown cells compared to control adipocytes. Furthermore, lipogenesis was reduced by SENP2-knockdown in adipocytes. Although TAG accumulation relative to total uptake was unchanged, there was increased mRNA expression of metabolically relevant genes such as UCP1 and PPARGC1A and mRNA and proteomic data revealed increased levels of mRNA and proteins related to mitochondrial function by SENP2-knockdown. In conclusion, SENP2 is an important regulator of energy metabolism in primary human adipocytes and its knockdown reduce glucose metabolism and lipid accumulation, while increasing lipid oxidation in human adipocytes., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Stefano Bartesaghi and Xiao-Rong Peng are employees at AstraZeneca. The remaining authors have no competing interests to declare., (© 2023 The Authors.)

Objective: In order to address the lack of data on the health and healthcare needs of trans and non-binary adults, NHS England includes questions asking about both gender and trans status in its surveys to support quality improvement programmes.We used self-reported data from the GP Patient Survey to answer the research question: what are the demographic characteristics, health conditions and healthcare experiences of trans and non-binary adults in England?, Design/setting: Nationally representative, population-based cross-sectional survey in England with survey data collection from January to March 2021., Participants: 840 691 survey respondents including 6333 trans and non-binary adults., Outcomes: We calculated weighted descriptive statistics, and using logistic regression explored 15 long-term physical and mental health conditions, and 18 patient experience items, covering overall experience, access, communication and continuity., Results: Trans and non-binary adults were younger, more likely to be from Asian, black, mixed or other ethnic groups and more likely to live in more deprived parts of the country. Age-specific patterns of long-term conditions were broadly similar among trans and non-binary adults compared with all other survey respondents, with some variation by condition. Overall, inequalities in long-term health conditions were largest for autism: OR (95% CI), 5.8 (5.0 to 6.6), dementia: 3.1 (2.5 to 3.9), learning disabilities: 2.8 (2.4 to 3.2) and mental health: 2.0 (1.9 to 2.2), with variation by age. In healthcare experience, disparities are much greater for interpersonal communication (OR for reporting a positive experience, range 0.4 to 0.7 across items) than access (OR range 0.8 to 1.2). Additionally, trans and non-binary adults report much higher preference for continuity 1.7 (1.6 to 1.8), with no evidence of any differences in being able to see or speak to a preferred general practitioner., Conclusion: This research adds up to date evidence about population demographics, health and healthcare needs to support healthcare improvement for trans and non-binary adults., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY. Published by BMJ.)

Metabolic alterations occurring in cancer cells have been seen to also occur in other tissues than cancerous tissue. For instance, cachexia, peripheral insulin resistance, or both are commonly seen in patients with cancer. We explored differences in substrate use in myotubes conditioned with the medium from a pancreatic cancer cell line, PANC-1, or primary human pancreatic cells, hPECs. Protein turnover was assessed using scintillation proximity assay, glucose and oleic acid handling were analyzed by substrate oxidation assay. We performed qPCR to study gene expression and immunoblotting and proteomic analyses to study protein expression. PANC-1-conditioned myotubes had an imbalance in protein turnover with decreased accumulation, increased decay, and decreased MYH2 gene expression. Glucose uptake decreased despite increased insulin-stimulated Akt phosphorylation. Fatty acid uptake increased, whereas fatty acid oxidation was unchanged, leading to accumulation of intracellular lipids (TAG) in PANC-1-conditioned myotubes. Secretome analyses revealed increased release of growth factors and growth factor receptor from PANC-1 cells, potentially affecting muscle cell metabolism. Myotubes exposed to pancreatic cancer cell medium displayed altered energy metabolism with increased protein/leucine turnover and lipid accumulation, while glucose uptake and oxidation reduced. This indicates production and release of substances from pancreatic cancer cells affecting skeletal muscle.

Introduction: Atrial fibrillation (AF) is a common arrhythmia associated with 30% of strokes, as well as other cardiovascular disease, dementia and death. AF meets many criteria for screening, but there is limited evidence that AF screening reduces stroke. Consequently, no countries recommend national screening programmes for AF. The Screening for Atrial Fibrillation with ECG to Reduce stroke (SAFER) trial aims to determine whether screening for AF is effective at reducing risk of stroke. The aim of the pilot study is to assess feasibility of the main trial and inform implementation of screening and trial procedures., Methods and Analysis: SAFER is planned to be a pragmatic randomised controlled trial (RCT) of over 100 000 participants aged 70 years and over, not on long-term anticoagulation therapy at baseline, with an average follow-up of 5 years. Participants are asked to record four traces every day for 3 weeks on a hand-held single-lead ECG device. Cardiologists remotely confirm episodes of AF identified by the device algorithm, and general practitioners follow-up with anticoagulation as appropriate. The pilot study is a cluster RCT in 36 UK general practices, randomised 2:1 control to intervention, recruiting approximately 12 600 participants. Pilot study outcomes include AF detection rate, anticoagulation uptake and other parameters to incorporate into sample size calculations for the main trial. Questionnaires sent to a sample of participants will assess impact of screening on psychological health. Process evaluation and qualitative studies will underpin implementation of screening during the main trial. An economic evaluation using the pilot data will confirm whether it is plausible that screening might be cost-effective., Ethics and Dissemination: The London-Central Research Ethics Committee (19/LO/1597) and Confidentiality Advisory Group (19/CAG/0226) provided ethical approval. Dissemination will be via publications, patient-friendly summaries, reports and engagement with the UK National Screening Committee., Trial Registration Number: ISRCTN72104369., Competing Interests: Competing interests: JM has performed consultancy work for BMS/Pfizer and Omron. FDRH reports occasional consultancy for BMS/Pfizer, Bayer and BI over the past 5 years. NA is a member of the UK National Screening Committee’s Adult Reference Group. MS is a full-time employee of AstraZeneca. MRC reports consultancy for AstraZeneca, Abbott, Medtronic, Bayer, Novartis, Boehringer-Ingelheim-Lilly Alliance, Servier & Pfizer over the past 5 years. RMc’s employer the University of Oxford receives consultancy and licencing payments from Omron and Sensyne for BP telemonitoring interventions. GYHL: Consultant and speaker for BMS/Pfizer, Boehringer Ingelheim and Daiichi-Sankyo. No fees are received personally. SJG has received honoraria from Astra Zeneca for lectures at postgraduate educational meetings for primary care teams about type 2 diabetes. BF has received speaker fees, honoraria, and non-financial support from the BMS and Pfizer Alliance; grants to the Institution for investigator-initiated studies from the BMS and Pfizer Alliance; and loan devices for investigatorinitiated studies from Alivecor: all were unrelated to the present study but related to screening for AF., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY. Published by BMJ.)

Background: Recent studies have highlighted that uncoupling of sarco-/endoplasmic reticulum Ca 2+ -ATPase (SERCA) by sarcolipin (SLN) increases ATP consumption and contributes to heat liberation. Exploiting this thermogenic mechanism in skeletal muscle may provide an attractive strategy to counteract obesity and associated metabolic disorders. In the present study, we have investigated the role of SLN on substrate metabolism in human skeletal muscle cells., Methods and Results: After generation of skeletal muscle cells with stable SLN knockdown (SLN-KD), cell viability, glucose and oleic acid (OA) metabolism, mitochondrial function, as well as gene expressions were determined. Depletion of SLN did not influence cell viability. However, glucose and OA oxidation were diminished in SLN-KD cells compared to control myotubes. Basal respiration measured by respirometry was also observed to be reduced in cells with SLN-KD. The metabolic perturbation in SLN-KD cells was reflected by reduced gene expression levels of peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α) and forkhead box O1 (FOXO1). Furthermore, accumulation of OA was increased in cells with SLN-KD compared to control cells. These effects were accompanied by increased lipid formation and incorporation of OA into complex lipids. Additionally, formation of complex lipids and free fatty acid from de novo lipogenesis with acetate as substrate was enhanced in SLN-KD cells. Detection of lipid droplets using Oil red O staining also showed increased lipid accumulation in SLN-KD cells., Conclusions: Overall, our study sheds light on the importance of SLN in maintaining metabolic homeostasis in human skeletal muscle. Findings from the current study suggest that therapeutic strategies involving SLN-mediated futile cycling of SERCA might have significant implications in the treatment of obesity and associated metabolic disorders., (© 2022. The Author(s).)

Background & Aims: Although long-chain omega-3 fatty acids (LCn-3FAs) regulate inflammatory pathways of relevance to non-alcoholic steatohepatitis (NASH), their susceptibility to peroxidation may limit their therapeutic potential. We compared the metabolism of eicosapentaenoic acid (EPA) with an engineered EPA derivative (icosabutate) in human hepatocytes in vitro and their effects on hepatic glutathione metabolism, oxidised lipids, inflammation, and fibrosis in a dietary mouse model of NASH, and in patients prone to fatty liver disease., Methods: Oxidation rates and cellular partitioning of EPA and icosabutate were compared in primary human hepatocytes. Comparative effects of delayed treatment with either low- (56 mg/kg) or high-dose (112 mg/kg) icosabutate were compared with EPA (91 mg/kg) or a glucagon-like peptide 1 receptor agonist in a choline-deficient (CD), L-amino acid-defined NASH mouse model. To assess the translational potential of these findings, effects on elevated liver enzymes and fibrosis-4 (FIB-4) score were assessed in overweight, hyperlipidaemic patients at an increased risk of NASH., Results: In contrast to EPA, icosabutate resisted oxidation and incorporation into hepatocytes. Icosabutate also reduced inflammation and fibrosis in conjunction with a reversal of CD diet-induced changes in the hepatic lipidome. EPA had minimal effect on any parameter and even worsened fibrosis in association with depletion of hepatic glutathione. In dyslipidaemic patients at risk of NASH, icosabutate rapidly normalised elevated plasma ALT, GGT and AST and reduced FIB-4 in patients with elevated ALT and/or AST., Conclusion: Icosabutate does not accumulate in hepatocytes and confers beneficial effects on hepatic oxidative stress, inflammation and fibrosis in mice. In conjunction with reductions in markers of liver injury in hyperlipidaemic patients, these findings suggest that structural engineering of LCn-3FAs offers a novel approach for the treatment of NASH., Lay Summary: Long-chain omega-3 fatty acids are involved in multiple pathways regulating hepatic inflammation and fibrosis, but their susceptibility to peroxidation and use as an energy source may limit their clinical efficacy. Herein, we show that a structurally modified omega-3 fatty acid, icosabutate, overcame these challenges and had markedly improved antifibrotic efficacy in a mouse model of non-alcoholic steatohepatitis. A hepatoprotective effect of icosabutate was also observed in patients with elevated circulating lipids, in whom it led to rapid reductions in markers of liver injury., Competing Interests: Conflict of interest NorthSea Therapeutics BV acquired the commercial rights for icosabutate. DS and JK are paid consultants and have stock options in NorthSea Therapeutics. DF and TS are employees of NorthSea Therapeutics BV but had no role in data collection. All other authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Please refer to the accompanying ICMJE disclosure forms for further details., (Copyright © 2021. Published by Elsevier B.V.)

Comparing energy metabolism in human skeletal muscle and primary skeletal muscle cells in obesity, while focusing on glucose and fatty acid metabolism, shows many common changes. Insulin-mediated glucose uptake in skeletal muscle and primary myotubes is decreased by obesity, whereas differences in basal glucose metabolism are inconsistent among studies. With respect to fatty acid metabolism, there is an increased uptake and storage of fatty acids and a reduced complete lipolysis, suggesting alterations in lipid turnover. In addition, fatty acid oxidation is decreased, probably at the level of complete oxidation, as β -oxidation may be enhanced in obesity, which indicates mitochondrial dysfunction. Metabolic changes in skeletal muscle with obesity promote metabolic inflexibility, ectopic lipid accumulation, and formation of toxic lipid intermediates. Skeletal muscle also acts as an endocrine organ, secreting myokines that participate in interorgan cross talk. This review highlights interventions and some possible targets for treatment through action on skeletal muscle energy metabolism. Effects of exercise in vivo on obesity have been compared with simulation of endurance exercise in vitro on myotubes (electrical pulse stimulation). Possible pharmaceutical targets, including signaling pathways and drug candidates that could modify lipid storage and turnover or increase mitochondrial function or cellular energy expenditure through adaptive thermogenic mechanisms, are discussed., (© 2021 The Authors. Obesity published by Wiley Periodicals LLC on behalf of The Obesity Society (TOS).)

Background and Objective: A number of studies have highlighted muscle-specific mechanisms of thermogenesis involving futile cycling of Ca 2+ driven by sarco (endo)plasmic reticulum Ca 2+ -ATPase (SERCA) and generating heat from ATP hydrolysis to be a promising strategy to counteract obesity and metabolic dysfunction. However, to the best of our knowledge, no experimental studies concerning the metabolic effects of pharmacologically targeting SERCA in human skeletal muscle cells have been reported. Thus, in the present study, we aimed to explore the effects of SERCA-activating compound, CDN1163, on energy metabolism in differentiated human skeletal muscle cells (myotubes)., Methods: In this study, we used primary myotube cultures derived from muscle biopsies of the musculus vastus lateralis and musculi interspinales from lean, healthy male donors. Energy metabolism in myotubes was studied using radioactive substrates. Oxygen consumption rate was assessed with the Seahorse XF24 bioanalyzer, whereas metabolic genes and protein expressions were determined by qPCR and immunoblotting, respectively., Results: Both acute (4 ​h) and chronic (5 days) treatment of myotubes with CDN1163 showed increased uptake and oxidation of glucose, as well as complete fatty acid oxidation in the presence of carbonyl cyanide 4-(trifluromethoxy)phenylhydrazone (FCCP). These effects were supported by measurement of oxygen consumption rate, in which the oxidative spare capacity and maximal respiration were enhanced after CDN1163-treatment. In addition, chronic treatment with CDN1163 improved cellular uptake of oleic acid (OA) and fatty acid β-oxidation. The increased OA metabolism was accompanied by enhanced mRNA-expression of carnitine palmitoyl transferase ( CPT ) 1B , pyruvate dehydrogenase kinase ( PDK ) 4, as well as increased AMP-activated protein kinase (AMPK) Thr172 phosphorylation. Moreover, following chronic CDN1163 treatment, the expression levels of stearoyl-CoA desaturase ( SCD ) 1 was decreased together with de novo lipogenesis from acetic acid and formation of diacylglycerol (DAG) from OA., Conclusion: Altogether, these results suggest that SERCA activation by CDN1163 enhances energy metabolism in human myotubes, which might be favourable in relation to disorders that are related to metabolic dysfunction such as obesity and type 2 diabetes mellitus., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Xiao-Rong Peng, Sven Göpel and Gavin O’ Mahony are employees of AstraZeneca. The other authors had no conflict of interest to disclose., (© 2021 The Authors.)

Sentrin-specific protease (SENP) 2 has been suggested as a possible novel drug target for the treatment of obesity and type 2 diabetes mellitus after observations of a palmitate-induced increase in SENP2 that lead to increased fatty acid oxidation and improved insulin sensitivity in skeletal muscle cells from mice. However, no precedent research has examined the role of SENP2 in human skeletal muscle cells. In the present work, we have investigated the impact of SENP2 on fatty acid and glucose metabolism as well as insulin sensitivity in human skeletal muscle using cultured primary human myotubes. Acute (4 ​h) oleic acid oxidation was reduced in SENP2-knockdown (SENP2-KD) cells compared to control cells, with no difference in uptake. After prelabeling (24 ​h) with oleic acid, total lipid content and incorporation into triacylglycerol was decreased, while incorporation into other lipids, as well as complete oxidation and β-oxidation was increased in SENP2-KD cells. Basal glucose uptake (i.e., not under insulin-stimulated conditions) was higher in SENP2-KD cells, whereas oxidation was similar to control myotubes. Further, basal glycogen synthesis was not different in SENP2-KD myotubes, but both insulin-stimulated glycogen synthesis and Akt Ser473 phosphorylation was completely blunted in SENP2-KD cells. In conclusion, SENP2 plays an important role in fatty acid and glucose metabolism in human myotubes. Interestingly, it also appears to have a pivotal role in regulating myotube insulin sensitivity. Future studies should examine the role of SENP2 in regulation of insulin sensitivity in other tissues and in vivo , defining the potential for SENP2 as a drug target., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2021 The Authors.)

Objective: To describe patterns of anticoagulation prescription and persistence for those aged ≥65 years with atrial fibrillation (AF)., Methods: Descriptive cohort study using electronic general practice records of patients in England, who attended an influenza vaccination aged ≥65 years and were diagnosed with AF between 2008 and 2018. Patients were stratified by 10-year age group and year of diagnosis. Proportion anticoagulated, type of anticoagulation (direct oral anticoagulant (DOAC) or warfarin) initiated at diagnosis and persistence with anticoagulation over time are reported., Results: 42 290 patients (49% female), aged 65-74 (n=11 722), 75-84 (n=19 055) and 85+ (n=11 513) years at AF diagnosis are included. Prescription of anticoagulation at diagnosis increased over the time period from 55% to 86% in people aged 65-74 years, from 54% to 86% in people aged 75-84 years and from 27% to 75% in people aged 85 years and over. By 2018, 92% of patients with newly diagnosed AF were started on a DOAC. Survivor function for 5-year persistence in patients prescribed DOAC was 0.80 (95% CI 0.77 to 0.82) and for warfarin 0.71 (95% CI 0.70 to 0.72). Survivor function for any anticoagulation at 5 years was 0.79 (95% CI 0.78 to 0.81), 0.73 (95% CI 0.72 to 0.75) and 0.58 (95% CI 0.59 to 0.64) for people aged 65-74, 75-84 and 85+ years, respectively., Conclusions: Rates of anticoagulation in AF in those aged ≥65 years have increased from 2008 to 2018, over which time period there has been a shift from initiating anticoagulation with warfarin to DOAC. Persistence with anticoagulation is higher in people on DOACs than on warfarin and in people aged <85 years., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY. Published by BMJ.)

With the redefinition of osteoarthritis (OA) and the understanding that the joint behaves as an organ, OA is now considered a systemic illness with a low grade of chronic inflammation. Mitochondrial dysfunction is well documented in OA and has the capacity to alter chondrocyte and synoviocyte function. Transmitochondrial cybrids are suggested as a useful cellular model to study mitochondrial biology in vitro, as they carry different mitochondrial variants with the same nuclear background. The aim of this work was to study mitochondrial and metabolic function of cybrids with mitochondrial DNA from healthy (N) and OA donors. In this work, the authors demonstrate that cybrids from OA patients behave differently from cybrids from N donors in several mitochondrial parameters. Furthermore, OA cybrids behave similarly to OA chondrocytes. These results enhance our understanding of the role of mitochondria in the degeneration process of OA and present cybrids as a useful model to study OA pathogenesis., (Copyright © 2021. Published by Elsevier Inc.)

Objectives: Atrial fibrillation (AF) is a heart condition associated with a fivefold increased risk of stroke. The condition can be detected in primary care and treatment can greatly reduce the risk of stroke. In recent years, a number of policy initiatives have tried to improve diagnosis and treatment of AF, including local National Health Service schemes and the Quality and Outcomes Framework. We aimed to examine trends in the incidence of recorded AF in primary care records from English practices between 2004 and 2018., Design: Longitudinal cohort study., Setting: English primary care electronic health records linked to Index of Multiple Deprivation data., Participants: Cohort of 3.5 million patients over 40 years old registered in general practices in England, contributing 22 million person-years of observation between 2004 and 2018., Primary and Secondary Outcome Measures: Incident AF was identified through newly recorded AF codes in the patients' records. Yearly incidence rates were stratified by gender, age group and a measure of deprivation., Results: Incidence rates were stable before 2010 and then rose and peaked in 2015 at 5.07 (95% CI 4.94 to 5.20) cases per 1000 person-years. Incidence was higher in males (4.95 (95% CI 4.91 to 4.99) cases per 1000 person-years vs 4.12 (95% CI 4.08 to 4.16) in females) and rises markedly with age (0.58 (95% CI 0.56 to 0.59) cases per 1000 person-years in 40-54 years old vs 21.7 (95% CI 21.4 to 22.0) cases in over 85s). The increase in incidence over time was observed mainly in people over the age of 75, particularly men. There was no evidence that temporal trends in incidence were associated with deprivation., Conclusions: Changes in clinical practice and policy initiatives since 2004 have been associated with increased rates of diagnosis of AF up until 2015, but rates declined from 2015 to 2018., Competing Interests: Competing interests: All authors report grants from the NIHR School of Primary Care Research, during the conduct of the study. JL reports grants from the Wellcome Trust and the National Institute for Health Research, outside the submitted work. JM is on an advisory board for BMS/Pfizer on an AF screening trial, and is chief investigator of an NIHR-funded programme grant on screening for atrial fibrillation. DE is a coinvestigator on this same NIHR programme., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY. Published by BMJ.)

Primary human myotubes represent an alternative system to intact skeletal muscle for the study of human diseases related to changes in muscle energy metabolism. This work aimed to study if fatty acid and glucose metabolism in human myotubes in vitro were related to muscle of origin, donor gender, age, or body mass index (BMI). Myotubes from a total of 82 donors were established from three different skeletal muscles, i.e., musculus vastus lateralis, musculus obliquus internus abdominis, and musculi interspinales, and cellular energy metabolism was evaluated. Multiple linear regression analyses showed that donor age had a significant effect on glucose and oleic acid oxidation after correcting for gender, BMI, and muscle of origin. Donor BMI was the only significant contributor to cellular oleic acid uptake, whereas cellular glucose uptake did not rely on any of the variables examined. Despite the effect of age on substrate oxidation, cellular mRNA expression of pyruvate dehydrogenase kinase 4 (PDK4) and peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PPARGC1A) did not correlate with donor age. In conclusion, donor age significantly impacts substrate oxidation in cultured human myotubes, whereas donor BMI affects cellular oleic acid uptake.

Background: /Objectives: We aimed to metabolically compare healthy primary human pancreatic epithelial cells (hPEC) to a pancreatic cancer cell line (PANC-1) and explore the effect on energy metabolism of exposing primary human myotubes to conditioned medium from hPEC and PANC-1 cells., Methods: Differences in metabolism were examined with radiolabeled glucose, oleic acid and lactic acid, and by qPCR. Mass spectrometry-based proteomics was used to study global protein secretion from the two cell types. Pathway analyses were performed., Results: PANC-1 cells tended to have higher glucose uptake, production of lactic acid, and glucose oxidation compared to hPEC cells. PANC-1 cells had higher uptake but lower oxidation of oleic acid, and mitochondrial reserve capacity from oleic acid was lower in PANC-1 cells. These differences in energy metabolism were reflected by differences in gene expressions and pathway analyses of the secretome. Conditioned medium from PANC-1 cells attenuated oleic acid oxidation in primary human myotubes., Conclusions: Metabolic characterization of the PANC-1 cells revealed a glycolytic phenotype since they had an active glucose oxidation. Furthermore, PANC-1 cells showed a lower oleic acid oxidation and secreted a high amount of proteins into conditioned medium that also induced a reduced oleic acid oxidation in myotubes., Competing Interests: Declaration of competing interest None., (Copyright © 2020 IAP and EPC. Published by Elsevier B.V. All rights reserved.)

Osteoarthritis (OA) is the most frequent joint disease; however, the etiopathogenesis is still unclear. Chondrocytes rely primarily on glycolysis to meet cellular energy demand, but studies implicate impaired mitochondrial function in OA pathogenesis. The relationship between mitochondrial dysfunction and OA has been established. The aim of the study was to examine the differences in glucose and Fatty Acids (FA) metabolism, especially with regards to metabolic flexibility, in cybrids from healthy (N) or OA donors. Glucose and FA metabolism were studied using D-[ 14 C(U)]glucose and [1- 14 C]oleic acid, respectively. There were no differences in glucose metabolism among the cybrids. Osteoarthritis cybrids had lower acid-soluble metabolites, reflecting incomplete FA β-oxidation but higher incorporation of oleic acid into triacylglycerol. Co-incubation with glucose and oleic acid showed that N but not OA cybrids increased their glucose metabolism. When treating with the mitochondrial inhibitor etomoxir, N cybrids still maintained higher glucose oxidation. Furthermore, OA cybrids had higher oxidative stress response. Combined, this indicated that N cybrids had higher metabolic flexibility than OA cybrids. Healthy donors maintained the glycolytic phenotype, whereas OA donors showed a preference towards oleic acid metabolism. Interestingly, the results indicated that cybrids from OA patients had mitochondrial impairments and reduced metabolic flexibility compared to N cybrids.

Previous studies have shown that chronic hyperglycemia impairs glucose and fatty acid oxidation in cultured human myotubes. To further study the hyperglycemia-induced suppression of oxidation, lactate oxidation, mitochondrial function and glycolytic rate were evaluated. Further, we examined the intracellular content of reactive oxygen species (ROS), production of lactate and conducted pathway-ANOVA analysis on microarray data. In addition, the roles of the pentose phosphate pathway (PPP) and the hexosamine pathway were evaluated. Lactic acid oxidation was suppressed in hyperglycemic versus normoglycaemic myotubes. No changes in mitochondrial function or ROS concentration were observed. Pathway-ANOVA analysis indicated several upregulated pathways in hyperglycemic cells, including glycolysis and PPP. Functional studies showed that glycolysis and lactate production were higher in hyperglycemic than normoglycaemic cells. However, there were no indications of involvement of PPP or the hexosamine pathway. In conclusion, hyperglycemia reduced substrate oxidation while increasing glycolysis and lactate production in cultured human myotubes.

In this study we compared fatty acid (FA) metabolism in myotubes established from athletic and sedentary young subjects. Six healthy sedentary (maximal oxygen uptake (VO 2max ) ≤ 46 ml/kg/min) and six healthy athletic (VO 2max  > 60 ml/kg/min) young men were included. Myoblasts were cultured and differentiated to myotubes from satellite cells isolated from biopsy of musculus vastus lateralis. FA metabolism was studied in myotubes using [ 14 C]oleic acid. Lipid distribution was assessed by thin layer chromatography, and FA accumulation, lipolysis and re-esterification were measured by scintillation proximity assay. Gene and protein expressions were studied. Myotubes from athletic subjects showed lower FA accumulation, lower incorporation of FA into total lipids, triacylglycerol (TAG), diacylglycerol and cholesteryl ester, higher TAG-related lipolysis and re-esterification, and higher complete oxidation and incomplete β-oxidation of FA compared to myotubes from sedentary subjects. mRNA expression of the mitochondrial electron transport chain complex III gene UQCRB was higher in cells from athletic compared to sedentary. Myotubes established from athletic subjects have higher lipid turnover and oxidation compared to myotubes from sedentary subjects. Our findings suggest that cultured myotubes retain some of the phenotypic traits of their donors.

Once assumed only to be a waste product of anaerobe glycolytic activity, lactate is now recognized as an energy source in skeletal muscles. While lactate metabolism has been extensively studied in vivo, underlying cellular processes are poorly described. This study aimed to examine lactate metabolism in cultured human myotubes and to investigate effects of lactate exposure on metabolism of oleic acid and glucose. Lactic acid, fatty acid and glucose metabolism were studied in myotubes using [ 14 C(U)]lactic acid, [ 14 C]oleic acid and [ 14 C(U)]glucose, respectively. Myotubes expressed both the MCT1, MCT2, MCT3 and MCT4 lactate transporters, and lactic acid was found to be a substrate for both glycogen synthesis and lipid storage. Pyruvate and palmitic acid inhibited lactic acid oxidation, whilst glucose and α-cyano-4-hydroxycinnamic acid inhibited lactic acid uptake. Acute addition of lactic acid inhibited glucose and oleic acid oxidation, whereas oleic acid uptake was increased. Pretreatment with lactic acid for 24 h did not affect glucose or oleic acid metabolism. By replacing glucose with lactic acid during the whole culturing period, glucose uptake and oxidation were increased by 2.8-fold and 3-fold, respectively, and oleic acid oxidation was increased 1.4-fold. Thus, lactic acid has an important role in energy metabolism of human myotubes.

We hypothesised that skeletal muscles of healthy young people have a large variation in oxidative capacity and fibre-type composition, and aimed therefore to investigate glucose metabolism in biopsies and myotubes isolated from musculus vastus lateralis from healthy males with varying degrees of maximal oxygen uptake. Trained and intermediary trained subjects showed higher carbohydrate oxidation in vivo. Fibre-type distribution in biopsies and myotubes did not differ between groups. There was no correlation between fibre-type I expression in biopsies and myotubes. Myotubes from trained had higher deoxyglucose accumulation and fractional glucose oxidation (glucose oxidation relative to glucose uptake), and were also more sensitive to the suppressive action of acutely added oleic acid to the cells. Despite lack of correlation of fibre types between skeletal muscle biopsies and cultured cells, myotubes from trained subjects retained some of their phenotypes in vitro with respect to enhanced glucose metabolism and metabolic flexibility.

Lipid droplet (LD) coating proteins are essential for the formation and stability of intracellular LDs. Plin2 is an abundant LD coating protein in skeletal muscle, but its importance for muscle function is unclear. We show that myotubes established from Plin2 -/- mice contain reduced content of LDs and accumulate less oleic acid (OA) in triacylglycerol (TAG) due to elevated LD hydrolysis in comparison with Plin2 +/+ myotubes. The reduced ability to store TAG in LDs in Plin2 -/- myotubes is accompanied by a shift in energy metabolism. Plin2 -/- myotubes are characterized by increased oxidation of OA, lower glycogen synthesis, and reduced glucose oxidation in comparison with Plin2 +/+ myotubes, perhaps reflecting competition between FAs and glucose as part of the Randle cycle. In accord with these metabolic changes, Plin2 -/- myotubes have elevated expression of Ppara and Ppargc1a , transcription factors that stimulate expression of genes important for FA oxidation, whereas genes involved in glucose uptake and oxidation are suppressed. Loss of Plin2 had no impact on insulin-stimulated Akt phosphorylation. Our results suggest that Plin2 is essential for protecting the pool of skeletal muscle LDs to avoid an uncontrolled hydrolysis of stored TAG and to balance skeletal muscle energy metabolism., (Copyright © 2017 by the American Society for Biochemistry and Molecular Biology, Inc.)

Background and Aims: Physical activity has preventive as well as therapeutic benefits for overweight subjects. In this study we aimed to examine effects of in vivo exercise on in vitro metabolic adaptations by studying energy metabolism in cultured myotubes isolated from biopsies taken before and after 12 weeks of extensive endurance and strength training, from healthy sedentary normal weight and overweight men., Methods: Healthy sedentary men, aged 40-62 years, with normal weight (body mass index (BMI) < 25 kg/m2) or overweight (BMI ≥ 25 kg/m2) were included. Fatty acid and glucose metabolism were studied in myotubes using [14C]oleic acid and [14C]glucose, respectively. Gene and protein expressions, as well as DNA methylation were measured for selected genes., Results: The 12-week training intervention improved endurance, strength and insulin sensitivity in vivo, and reduced the participants' body weight. Biopsy-derived cultured human myotubes after exercise showed increased total cellular oleic acid uptake (30%), oxidation (46%) and lipid accumulation (34%), as well as increased fractional glucose oxidation (14%) compared to cultures established prior to exercise. Most of these exercise-induced increases were significant in the overweight group, whereas the normal weight group showed no change in oleic acid or glucose metabolism., Conclusions: 12 weeks of combined endurance and strength training promoted increased lipid and glucose metabolism in biopsy-derived cultured human myotubes, showing that training in vivo are able to induce changes in human myotubes that are discernible in vitro.

Thio-ether fatty acids (THEFAs), including the parent 2-(tetradecylthio)acetic acid (TTA), are modified fatty acids (FAs) that have profound effects on lipid metabolism given that they are blocked for β-oxidation, and able to act as peroxisome proliferator-activated receptor (PPAR) agonists. Therefore, TTA in particular has been tested clinically for its therapeutic potential against metabolic syndrome related disorders. Here, we describe the preparation of THEFAs based on the TTA scaffold with either a double or a triple bond. These are tested in cultured human skeletal muscle cells (myotubes), either as free acid or following esterification as phospholipids, lysophospholipids or monoacylglycerols. Metabolic effects are assessed in terms of cellular bioavailabilities in myotubes, by FA substrate uptake and oxidation studies, and gene regulation studies with selected PPAR-regulated genes. We note that the inclusion of a triple bond promotes THEFA-mediated FA oxidation. Furthermore, esterification of THEFAs as lysophospholipids also promotes FA oxidation effects. Given that the apparent clinical benefits of TTA administration were offset by dose limitation and poor bioavailability, we discuss the possibility that a selection of our latest THEFAs and THEFA-containing lipids might be able to fulfill the therapeutic potential of the parent TTA while minimizing required doses for efficacy, side-effects and adverse reactions., (Copyright © 2016 Elsevier Ltd. All rights reserved.)