Remodeling of skeletal muscle myosin metabolic states in hibernating mammals.

Hibernation is a period of metabolic suppression utilized by many small and large mammal species to survive during winter periods. As the underlying cellular and molecular mechanisms remain incompletely understood, our study aimed to determine whether skeletal muscle myosin and its metabolic efficiency undergo alterations during hibernation to optimize energy utilization. We isolated muscle fibers from small hibernators, Ictidomys tridecemlineatus and Eliomys quercinus and larger hibernators, Ursus arctos and Ursus americanus. We then conducted loaded Mant-ATP chase experiments alongside X-ray diffraction to measure resting myosin dynamics and its ATP demand. In parallel, we performed multiple proteomics analyses. Our results showed a preservation of myosin structure in U. arctos and U. americanus during hibernation, whilst in I. tridecemlineatus and E. quercinus, changes in myosin metabolic states during torpor unexpectedly led to higher levels in energy expenditure of type II, fast-twitch muscle fibers at ambient lab temperatures (20 °C). Upon repeating loaded Mant-ATP chase experiments at 8 °C (near the body temperature of torpid animals), we found that myosin ATP consumption in type II muscle fibers was reduced by 77-107% during torpor compared to active periods. Additionally, we observed Myh2 hyper-phosphorylation during torpor in I. tridecemilineatus, which was predicted to stabilize the myosin molecule. This may act as a potential molecular mechanism mitigating myosin-associated increases in skeletal muscle energy expenditure during periods of torpor in response to cold exposure. Altogether, we demonstrate that resting myosin is altered in hibernating mammals, contributing to significant changes to the ATP consumption of skeletal muscle. Additionally, we observe that it is further altered in response to cold exposure and highlight myosin as a potentially contributor to skeletal muscle non-shivering thermogenesis.

Many animals use hibernation as a tactic to survive harsh winters. During this dormant, inactive state, animals reduce or limit body processes, such as heart rate and body temperature, to minimise their energy use. To conserve energy during hibernation, animals can use different approaches. For example, garden dormice undergo periodic states of extremely low core temperatures (down to 4­8^oC); whereas Eurasian brown bears see milder temperature drops (down to 23­25^oC). An important organ that changes during hibernation is skeletal muscle. Skeletal muscle typically uses large amounts of energy, making up around 50% of body mass. To survive, hibernating animals must change how their skeletal muscle uses energy. Traditionally, active myosin ­ a protein found in muscles that helps muscles to contract ­ was thought to be responsible for most of the energy use by skeletal muscle. But, more recently, resting myosin has also been found to use energy when muscles are relaxed. Lewis et al. studied myosin and skeletal muscle energy use changes during hibernation and whether they could impact the metabolism of hibernating animals. Lewis et al. assessed myosin changes in muscle samples from squirrels, dormice and bears during hibernation and during activity. Experiments showed changes in resting myosin in squirrels and dormice (whose temperature drops to 4­8^oC during hibernation) but not in bears. Further analysis revealed that cooling samples from non-hibernating muscle to 4­8^oC increased energy use in resting myosin, thereby generating heat. However, no increase in energy use was found after cooling hibernating muscle samples to 4­8^oC. This suggest that resting myosin generates heat at cool temperatures ­ a mechanism that is switched off in hibernating animals to allow them to cool their body temperature. These findings reveal key insights into how animals conserve energy during hibernation. In addition, the results show that myosin regulates energy use in skeletal muscles, which indicates myosin may be a potential drug target in metabolic diseases, such as obesity.

Bivalirudin versus heparin in ST and non-ST-segment elevation myocardial infarction-Outcomes at two years.

BACKGROUND: The registry-based randomized VALIDATE-SWEDEHEART trial (NCT02311231) compared bivalirudin vs. heparin in patients undergoing percutaneous coronary intervention (PCI) for myocardial infarction (MI). It showed no difference in the composite primary endpoint of death, MI, or major bleeding at 180 days. Here, we report outcomes at two years. METHODS: Analysis of primary and secondary endpoints at two years of follow-up was prespecified in the study protocol. We report the study results for the extended follow-up time here. RESULTS: In total, 6006 patients were enrolled, 3005 with ST-segment elevation MI (STEMI) and 3001 with Non-STEMI (NSTEMI), representing 70 % of all eligible patients with these diagnoses during the study. The primary endpoint occurred in 14.0 % (421 of 3004) in the bivalirudin group compared with 14.3 % (429 of 3002) in the heparin group (hazard ratio [HR] 0.97; 95 % confidence interval [CI], 0.85-1.11; P = 0.70) at one year and in 16.7 % (503 of 3004) compared with 17.1 % (514 of 3002), (HR 0.97; 95 % CI, 0.96-1.10; P = 0.66) at two years. The results were consistent in patients with STEMI and NSTEMI and across major subgroups. CONCLUSIONS: Until the two-year follow-up, there were no differences in endpoints between patients with MI undergoing PCI and allocated to bivalirudin compared with those allocated to heparin. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT02311231.

[Registration of national health registry-based research]. / Registrering av forskning baserad på nationella hälsoregister.

In medical research as a whole, frequent inaccurate or biased findings are of international concern. One measure against reporting biases is study registration before the start of data collection (preregistration), preferably together with the statistical analysis plan. This meta-research study systematically evaluated registration of Swedish observational research based on national health registries. In a random sample of registry-based observational studies published 2010-2022, very few were preregistered with a publicly available analysis plan (<1 procent). Ideas from the meta-research literature can be leveraged to strengthen the brand of Swedish registry-based observational studies and counteract reporting bias.

Effects of pharmacological interventions on mortality in patients with Takotsubo syndrome: a report from the SWEDEHEART registry.

AIMS: Takotsubo syndrome (TS) is a heart condition mimicking acute myocardial infarction. TS is characterized by a sudden weakening of the heart muscle, usually triggered by physical or emotional stress. In this study, we aimed to investigate the effect of pharmacological interventions on short- and long-term mortality in patients with TS. METHODS AND RESULTS: We analysed data from the SWEDEHEART (the Swedish Web System for Enhancement and Development of Evidence-based care in Heart disease Evaluated According to Recommended Therapies) registry, which included patients who underwent coronary angiography between 2009 and 2016. In total, we identified 1724 patients with TS among 228 263 individuals in the registry. The average age was 66 ± 14 years, and 77% were female. Nearly half of the TS patients (49.4%) presented with non-ST-elevation acute coronary syndrome, and a quarter (25.9%) presented with ST-elevation myocardial infarction. Most patients (79.1%) had non-obstructive coronary artery disease on angiography, while 11.7% had a single-vessel disease and 9.2% had a multivessel disease. All patients received at least one pharmacological intervention; most of them used beta-blockers (77.8% orally and 8.3% intravenously) or antiplatelet agents [aspirin (66.7%) and P2Y12 inhibitors (43.6%)]. According to the Kaplan-Meier estimator, the probability of all-cause mortality was 2.5% after 30 days and 16.6% after 6 years. The median follow-up time was 877 days. Intravenous use of inotropes and diuretics was associated with increased 30 day mortality in TS [hazard ratio (HR) = 9.92 (P < 0.001) and HR = 3.22 (P = 0.001), respectively], while angiotensin-converting enzyme inhibitors and statins were associated with decreased long-term mortality [HR = 0.60 (P = 0.025) and HR = 0.62 (P = 0.040), respectively]. Unfractionated and low-molecular-weight heparins were associated with reduced 30 day mortality [HR = 0.63 (P = 0.01)]. Angiotensin receptor blockers, oral anticoagulants, P2Y12 antagonists, aspirin, and beta-blockers did not statistically correlate with mortality. CONCLUSIONS: Our findings suggest that some medications commonly used to treat TS are associated with higher mortality, while others have lower mortality. These results could inform clinical decision-making and improve patient outcomes in TS. Further research is warranted to validate these findings and to identify optimal pharmacological interventions for patients with TS.

Remodelling of Skeletal Muscle Myosin Metabolic States in Hibernating Mammals.

Hibernation is a period of metabolic suppression utilized by many small and large mammal species to survive during winter periods. As the underlying cellular and molecular mechanisms remain incompletely understood, our study aimed to determine whether skeletal muscle myosin and its metabolic efficiency undergo alterations during hibernation to optimize energy utilization. We isolated muscle fibers from small hibernators, Ictidomys tridecemlineatus and Eliomys quercinus and larger hibernators, Ursus arctos and Ursus americanus. We then conducted loaded Mant-ATP chase experiments alongside X-ray diffraction to measure resting myosin dynamics and its ATP demand. In parallel, we performed multiple proteomics analyses. Our results showed a preservation of myosin structure in U. arctos and U. americanus during hibernation, whilst in I. tridecemlineatus and E. quercinus, changes in myosin metabolic states during torpor unexpectedly led to higher levels in energy expenditure of type II, fast-twitch muscle fibers at ambient lab temperatures (20°C). Upon repeating loaded Mant-ATP chase experiments at 8°C (near the body temperature of torpid animals), we found that myosin ATP consumption in type II muscle fibers was reduced by 77-107% during torpor compared to active periods. Additionally, we observed Myh2 hyper-phosphorylation during torpor in I. tridecemilineatus, which was predicted to stabilize the myosin molecule. This may act as a potential molecular mechanism mitigating myosin-associated increases in skeletal muscle energy expenditure during periods of torpor in response to cold exposure. Altogether, we demonstrate that resting myosin is altered in hibernating mammals, contributing to significant changes to the ATP consumption of skeletal muscle. Additionally, we observe that it is further altered in response to cold exposure and highlight myosin as a potentially contributor to skeletal muscle non-shivering thermogenesis.

Five-Year Follow-Up After Transcatheter Aortic Valve Implantation in Patients with Severe Aortic Stenosis and Concomitant Coronary Artery Disease: A Single-Center Experience

ABSTRACT Introduction: There is no consensus on the impact of coronary artery disease in patients undergoing transcatheter aortic valve implantation. Therefore, the objective of this study was, in a single-center setting, to evaluate the five-year outcome of transcatheter aortic valve implantation patients with or without coronary artery disease. Methods: All transcatheter aortic valve implantation patients between 2009 and 2019 were included and grouped according to the presence or absence of coronary artery disease. The primary endpoint, five-year all-cause mortality, was evaluated using Cox regression adjusted for age, sex, procedure years, and comorbidities. Comorbidities interacting with coronary artery disease were evaluated with interaction tests. In-hospital complications was the secondary endpoint. Results: In total, 176 patients had aortic stenosis and concomitant coronary artery disease, while 170 patients had aortic stenosis only. Mean follow-up was 2.2±1.6 years. There was no difference in the adjusted five-year all-cause mortality between transcatheter aortic valve implantation patients with and without coronary artery disease (hazard ratio 1.00, 95% confidence interval 0.59-1.70, P=0.99). In coronary artery disease patients, impaired renal function, peripheral arterial disease, or ejection fraction < 50% showed a significant interaction effect with higher five-year all-cause mortality. No significant differences in complications between the groups were found. Conclusion: Five-year mortality did not differ between transcatheter aortic valve implantation patients with or without coronary artery disease. However, in patients with coronary artery disease and impaired renal function, peripheral arterial disease, or ejection fraction < 50%, we found significantly higher five-year all-cause mortality.

Predicting target lesion failure following percutaneous coronary intervention through machine learning risk assessment models.

Aims: Central to the practice of precision medicine in percutaneous coronary intervention (PCI) is a risk-stratification tool to predict outcomes following the procedure. This study is intended to assess machine learning (ML)-based risk models to predict clinically relevant outcomes in PCI and to support individualized clinical decision-making in this setting. Methods and results: Five different ML models [gradient boosting classifier (GBC), linear discrimination analysis, Naïve Bayes, logistic regression, and K-nearest neighbours algorithm) for the prediction of 1-year target lesion failure (TLF) were trained on an extensive data set of 35 389 patients undergoing PCI and enrolled in the global, all-comers e-ULTIMASTER registry. The data set was split into a training (80%) and a test set (20%). Twenty-three patient and procedural characteristics were used as predictive variables. The models were compared for discrimination according to the area under the receiver operating characteristic curve (AUC) and for calibration. The GBC model showed the best discriminative ability with an AUC of 0.72 (95% confidence interval 0.69-0.75) for 1-year TLF on the test set. The discriminative ability of the GBC model for the components of TLF was highest for cardiac death with an AUC of 0.82, followed by target vessel myocardial infarction with an AUC of 0.75 and clinically driven target lesion revascularization with an AUC of 0.68. The calibration was fair until the highest risk deciles showed an underestimation of the risk. Conclusion: Machine learning-derived predictive models provide a reasonably accurate prediction of 1-year TLF in patients undergoing PCI. A prospective evaluation of the predictive score is warranted. Registration: Clinicaltrial.gov identifier is NCT02188355.

Optimal timing of influenza vaccination among patients with acute myocardial infarction - Findings from the IAMI trial.

Influenza vaccination reduces the risk of adverse cardiovascular events.The IAMI trial randomly assigned 2571 patients with acute myocardial infarction (AMI) to receive influenza vaccine or saline placebo during their index hospital admission. It was conducted at 30 centers in 8 countries from October 1, 2016 to March 1, 2020. In this post-hoc exploratory sub-study, we compare the trial outcomes in patients receiving early season vaccination (n = 1188) and late season vaccination (n = 1344).The primary endpoint wasthe composite of all-cause death, myocardial infarction (MI), or stent thrombosis at 12 months. Thecumulative incidence of the primary and key secondary endpoints by randomized treatment and early or late vaccination was estimated using the Kaplan-Meier method. In the early vaccinated group, the primary composite endpoint occurred in 36 participants (6.0%) assigned to influenza vaccine and 49 (8.4%) assigned to placebo (HR 0.69; 95% CI 0.45 to 1.07), compared to 31 participants (4.7%) assigned to influenza vaccine and 42 (6.2%) assigned to placebo (HR 0.74; 95% CI 0.47 to 1.18) in the late vaccinated group (P = 0.848 for interaction on HR scale at 1 year). We observed similar estimates for the key secondary endpoints of all-cause death and CV death. There was no statistically significant difference in vaccine effectiveness against adverse cardiovascular events by timing of vaccination. The effect of vaccination on all-cause death at one year was more pronounced in the group receiving early vaccination (HR 0.50; 95% CI, 0.29 to 0.86) compared late vaccination group (HR 0.75; 35% CI, 0.40 to 1.40) but there was no statistically significant difference between these groups (Interaction P = 0.335). In conclusion,there is insufficient evidence from the trial to establish whether there is a difference in efficacy between early and late vaccinationbut regardless of vaccination timing we strongly recommend influenza vaccination in all patients with cardiovascular diseases.

Five-Year Follow-Up After Transcatheter Aortic Valve Implantation in Patients with Severe Aortic Stenosis and Concomitant Coronary Artery Disease: A Single-Center Experience.

INTRODUCTION: There is no consensus on the impact of coronary artery disease in patients undergoing transcatheter aortic valve implantation. Therefore, the objective of this study was, in a single-center setting, to evaluate the five-year outcome of transcatheter aortic valve implantation patients with or without coronary artery disease. METHODS: All transcatheter aortic valve implantation patients between 2009 and 2019 were included and grouped according to the presence or absence of coronary artery disease. The primary endpoint, five-year all-cause mortality, was evaluated using Cox regression adjusted for age, sex, procedure years, and comorbidities. Comorbidities interacting with coronary artery disease were evaluated with interaction tests. In-hospital complications was the secondary endpoint. RESULTS: In total, 176 patients had aortic stenosis and concomitant coronary artery disease, while 170 patients had aortic stenosis only. Mean follow-up was 2.2±1.6 years. There was no difference in the adjusted five-year all-cause mortality between transcatheter aortic valve implantation patients with and without coronary artery disease (hazard ratio 1.00, 95% confidence interval 0.59-1.70, P=0.99). In coronary artery disease patients, impaired renal function, peripheral arterial disease, or ejection fraction < 50% showed a significant interaction effect with higher five-year all-cause mortality. No significant differences in complications between the groups were found. CONCLUSION: Five-year mortality did not differ between transcatheter aortic valve implantation patients with or without coronary artery disease. However, in patients with coronary artery disease and impaired renal function, peripheral arterial disease, or ejection fraction < 50%, we found significantly higher five-year all-cause mortality.

Pleiotropic Effects of Influenza Vaccination.

Influenza vaccines are designed to mimic natural influenza virus exposure and stimulate a long-lasting immune response to future infections. The evolving nature of the influenza virus makes vaccination an important and efficacious strategy to reduce healthcare-related complications of influenza. Several lines of evidence indicate that influenza vaccination may induce nonspecific effects, also referred to as heterologous or pleiotropic effects, that go beyond protection against infection. Different explanations are proposed, including the upregulation and downregulation of cytokines and epigenetic reprogramming in monocytes and natural killer cells, imprinting an immunological memory in the innate immune system, a phenomenon termed "trained immunity". Also, cross-reactivity between related stimuli and bystander activation, which entails activation of B and T lymphocytes without specific recognition of antigens, may play a role. In this review, we will discuss the possible nonspecific effects of influenza vaccination in cardiovascular disease, type 1 diabetes, cancer, and Alzheimer's disease, future research questions, and potential implications. A discussion of the potential effects on infections by other pathogens is beyond the scope of this review.

Hibernation and plasma lipids in free-ranging brown bears-implications for diabetes.

Brown bears (Ursus arctos) prepare for winter by overeating and increasing adipose stores, before hibernating for up to six months without eating, drinking, and with minimal movement. In spring, the bears exit the den without any damage to organs or physiology. Recent clinical research has shown that specific lipids and lipid profiles are of special interest for diseases such as diabetes type 1 and 2. Furthermore, rodent experiments show that lipids such as sulfatide protects rodents against diabetes. As free-ranging bears experience fat accumulation and month-long physical inactivity without developing diabetes, they could possibly be affected by similar protective measures. In this study, we investigated whether lipid profiles of brown bears are related to protection against hibernation-induced damage. We sampled plasma from 10 free-ranging Scandinavian brown bears during winter hibernation and repeated sampling during active state in the summer period. With quantitative shotgun lipidomics and liquid chromatography-mass spectrometry, we profiled 314 lipid species from 26 lipid classes. A principal component analysis revealed that active and hibernation samples could be distinguished from each other based on their lipid profiles. Six lipid classes were significantly altered when comparing plasma from active state and hibernation: Hexosylceramide, phosphatidylglycerol, and lysophosphatidylglycerol were higher during hibernation, while phosphatidylcholine ether, phosphatidylethanolamine ether, and phosphatidylinositol were lower. Additionally, sulfatide species with shorter chain lengths were lower, while longer chain length sulfatides were higher during hibernation. Lipids that are altered in bears are described by others as relevant for and associated with diabetes, which strengthens their position as potential effectors during hibernation. From this analysis, a range of lipids are suggested as potential protectors of bear physiology, and of potential importance in diabetes.

Body mass is associated with hibernation length, body temperature, and heart rate in free-ranging brown bears.

BACKGROUND: Despite centuries of research, debate remains on the scaling of metabolic rate to mass especially for intraspecific cases. The high variation of body mass within brown bears presents a unique opportunity to study the intraspecific effects of body mass on physiological variables. The amplitude of metabolic rate reduction in hibernators is dependent on body mass of the species. Small hibernators have high metabolic rates when euthermic but experience a drastic decrease in body temperature during torpor, which is necessary to reach a very low metabolic rate. Conversely, large hibernators, such as the brown bear (Ursus arctos), show a moderate decrease in temperature during hibernation, thought to be related to the bear's large size. We studied body mass, abdominal body temperature, heart rate, and accelerometer-derived activity from 63 free-ranging brown bears (1-15 years old, 15-233 kg). We tested for relationships between body mass and body temperature, heart rate, and hibernation duration. RESULTS: The smallest individuals maintained lower body temperatures during hibernation, hibernated longer, and ended hibernation later than large bears. Unlike body temperature, winter heart rates were not associated with body mass. In summer, the opposite pattern was found, with smaller individuals having higher body temperature and daytime heart rates. Body mass was associated with body temperature in the winter hypometabolic state, even in a large hibernating mammal. Smaller bears, which are known to have higher thermal conductance, reached lower body temperatures during hibernation. During summer, smaller bears had higher body temperatures and daytime heart rates, a phenomenon not previously documented within a single mammalian species. CONCLUSION: We conclude that the smallest bears hibernated more deeply and longer than large bears, likely from a combined effect of basic thermodynamics, the higher need for energy savings, and a lower cost of warming up a smaller body.

Formerly bile-farmed bears as a model of accelerated ageing.

Bear bile-farming is common in East and Southeast Asia and this farming practice often results in irreversible health outcomes for the animals. We studied long-term effects of chronic bacterial and sterile hepatobiliary inflammation in 42 Asiatic black bears (Ursus thibetanus) rescued from Vietnamese bile farms. The bears were examined under anesthesia at least twice as part of essential medical interventions. All bears were diagnosed with chronic low-grade sterile or bacterial hepatobiliary inflammation along with pathologies from other systems. Our main finding was that the chronic low-grade inflammatory environment associated with bile extraction in conjunction with the suboptimal living conditions on the farms promoted and accelerated the development of age-related pathologies such as chronic kidney disease, obese sarcopenia, cardiovascular remodeling, and degenerative joint disease. Through a biomimetic approach, we identified similarities with inflammation related to premature aging in humans and found significant deviations from the healthy ursid phenotype. The pathological parallels with inflammageing and immuno-senescence induced conditions in humans suggest that bile-farmed bears may serve as animal models to investigate pathophysiology and deleterious effects of lifestyle-related diseases.

Elevated plasma phospholipid n-3 docosapentaenoic acid concentrations during hibernation.

Factors for initiating hibernation are unknown, but the condition shares some metabolic similarities with consciousness/sleep, which has been associated with n-3 fatty acids in humans. We investigated plasma phospholipid fatty acid profiles during hibernation and summer in free-ranging brown bears (Ursus arctos) and in captive garden dormice (Eliomys quercinus) contrasting in their hibernation patterns. The dormice received three different dietary fatty acid concentrations of linoleic acid (LA) (19%, 36% and 53%), with correspondingly decreased alpha-linolenic acid (ALA) (32%, 17% and 1.4%). Saturated and monounsaturated fatty acids showed small differences between summer and hibernation in both species. The dormice diet influenced n-6 fatty acids and eicosapentaenoic acid (EPA) concentrations in plasma phospholipids. Consistent differences between summer and hibernation in bears and dormice were decreased ALA and EPA and marked increase of n-3 docosapentaenoic acid and a minor increase of docosahexaenoic acid in parallel with several hundred percent increase of the activity index of elongase ELOVL2 transforming C20-22 fatty acids. The highest LA supply was unexpectantly associated with the highest transformation of the n-3 fatty acids. Similar fatty acid patterns in two contrasting hibernating species indicates a link to the hibernation phenotype and requires further studies in relation to consciousness and metabolism.

Paper II: thematic framework analysis of registry-based randomized controlled trials provided insights for designing trial ready registries.

OBJECTIVES: Registry-based randomized controlled trials (RRCTs) are increasingly used, promising to address challenges associated with traditional randomized controlled trials. We identified strengths and limitations reported in planned and completed RRCTs to inform future RRCTs. STUDY DESIGN AND SETTING: We conducted an environmental scan of literature discussing conceptual or methodological strengths and limitations of using registries for trial design and conduct (n = 12), followed by an analysis of RRCT protocols (n = 13) and reports (n = 77) identified from a scoping review. Using framework analysis, we developed and refined a conceptual framework of RRCT-specific strengths and limitations. We mapped and interpreted strengths and limitations discussed by authors of RRCT articles using framework codes and quantified the frequencies at which these were mentioned. RESULTS: Our conceptual framework identified six main RRCT strengths and four main RRCT limitations. Considering implications for RRCT conduct and design, we formulated ten recommendations for registry designers, administrators, and trialists planning future RRCTs. CONCLUSION: Consideration and application of empirically underpinned recommendations for future registry design and trial conduct may help trialists utilize registries and RRCTs to their full potential.

Immobility-associated thromboprotection is conserved across mammalian species from bear to human.

Venous thromboembolism (VTE) comprising deep venous thrombosis and pulmonary embolism is a major cause of morbidity and mortality. Short-term immobility-related conditions are a major risk factor for the development of VTE. Paradoxically, long-term immobilized free-ranging hibernating brown bears and paralyzed spinal cord injury (SCI) patients are protected from VTE. We aimed to identify mechanisms of immobility-associated VTE protection in a cross-species approach. Mass spectrometry-based proteomics revealed an antithrombotic signature in platelets of hibernating brown bears with heat shock protein 47 (HSP47) as the most substantially reduced protein. HSP47 down-regulation or ablation attenuated immune cell activation and neutrophil extracellular trap formation, contributing to thromboprotection in bears, SCI patients, and mice. This cross-species conserved platelet signature may give rise to antithrombotic therapeutics and prognostic markers beyond immobility-associated VTE.

The impact of COVID-19 and COVID vaccination on cardiovascular outcomes.

COVID-19 is an independent risk factor for cardiovascular disease. COVID-19 vaccination may prevent this, but in some cases, COVID-19 vaccination may cause myocarditis or pericarditis. Patients with COVID-19 may present with non-specific symptoms that have a cardiac origin. This review examines the cardiovascular complications of COVID-19 infection and the impact of COVID-19 vaccination. COVID-19 cardiovascular complications include myocardial injury, pericarditis, coagulopathy, myocardial infarction, heart failure, arrhythmias, and persistent post-acute risk of adverse cardiovascular outcomes. Diagnostic and referral pathways for non-specific symptoms, such as dyspnoea and fatigue, remain unclear. COVID-19 vaccination is cardioprotective overall but is associated with myopericarditis in young males, though at a lower rate than following SARS-CoV-2 infection. Increased awareness among primary care physicians of potential cardiovascular causes of non-specific post-COVID-19 symptoms, including in younger adults, such as fatigue, dyspnoea, and chest pain, is essential. We recommend full vaccination with scheduled booster doses, optimal management of cardiovascular risk factors, rapid treatment of COVID-19, and clear diagnostic, referral, and management pathways for patients presenting with non-specific symptoms to rule out cardiac complications.

Prognostic value of early sustained ventricular arrhythmias in ST-segment elevation myocardial infarction treated by primary percutaneous coronary intervention: A substudy of VALIDATE-SWEDEHEART trial.

Background: Prognostic assessment of ventricular tachycardia (VT) or ventricular fibrillation (VF) in ST-segment elevation myocardial infarction (STEMI) is based mainly on distinguishing between early (<48 hours) and late arrhythmias, and does not take into account its time distribution with regard to reperfusion, or type of arrhythmia. Objective: We analyzed the prognostic value of early ventricular arrhythmias (VAs) in STEMI with regard to their type and timing. Methods: The prespecified analysis of the multicenter prospective Bivalirudin versus Heparin in ST-Segment and Non-ST-Segment Elevation Myocardial Infarctionin Patients on Modern Antiplatelet Therapy in the Swedish Web System for Enhancement and Development of Evidence-based Care in Heart Disease evaluated according to Recommended Therapies Registry Trial included 2886 STEMI patients undergoing primary percutaneous coronary intervention (PCI). VA episodes were characterized regarding their type and timing. Survival status at 180 days was assessed through the population registry. Results: Nonmonomorphic VT or VF was observed in 97 (3.4%) and monomorphic VT in 16 (0.5%) patients. Only 3 (2.7%) early VA episodes occurred after 24 hours from symptom onset. VA was associated with higher risk of death (hazard ratio 3.59; 95% confidence interval [CI] 2.01-6.42) after adjustment for age, sex, and STEMI localization. VA after PCI was associated with an increased mortality compared with VA before PCI (hazard ratio 6.68; 95% CI 2.90-15.41). Early VA was associated with in-hospital mortality (odds ratio 7.39; 95% CI 3.68-14.83) but not with long-term prognosis in patients discharged alive. The type of VA was not associated with mortality. Conclusion: VA after PCI was associated with an increased mortality compared with VA before PCI. Long-term prognosis did not differ between patients with monomorphic VT and nonmonomorphic VT or VF, but events were few. VA incidence during 24 to 48 hours of STEMI is negligibly low, thus precluding assessment of its prognostic importance.

Hypothyroidism in hibernating brown bears.

Brown bears hibernate throughout half of the year as a survival strategy to reduce energy consumption during prolonged periods with scarcity of food and water. Thyroid hormones are the major endocrine regulators of basal metabolic rate in humans. Therefore, we aimed to determine regulations in serum thyroid hormone levels in hibernation compared to the active state to investigate if these are involved in the adaptions for hibernation.We used electrochemiluminescence immunoassay to quantify total triiodothyronine (T3) and thyroxine (T4) levels in hibernation and active state in paired serum samples from six subadult Scandinavian brown bears. Additionally, we determined regulations in the liver mRNA levels of three major thyroid hormone-binding proteins; thyroxine-binding globulin (TBG), transthyretin (TTR), and albumin, by analysis of previously published grizzly bear RNA sequencing data.We found that bears were hypothyroid when hibernating with T4 levels reduced to less than 44% (P = 0.008) and T3 levels reduced to less than 36% (P = 0.016) of those measured in the active state. In hibernation, mRNA levels of TBG and albumin increased to 449% (P = 0.031) and 121% (P = 0.031), respectively, of those measured in the active state. TTR mRNA levels did not change.Hibernating bears are hypothyroid and share physiologic features with hypothyroid humans, including decreased basal metabolic rate, bradycardia, hypothermia, and fatigue. We speculate that decreased thyroid hormone signaling is a key mediator of hibernation physiology in bears. Our findings shed light on the translational potential of bear hibernation physiology to humans for whom a similar hypometabolic state could be of interest in specific conditions.