Can the electrophysiological action of rosiglitazone explain its cardiac side effects?

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Effect of thymol on kinetic properties of Ca and K currents in rat skeletal muscle

BACKGROUND: Thymol is widely used as a general antiseptic and antioxidant compound in the medical practice and industry, and also as a stabilizer to several therapeutic agents, including halothane. Thus intoxication with thymol may occur in case of ingestion or improper anesthesia. In the present study, therefore, concentration-dependent effects of thymol (30–600 micro-grams) were studied on calcium and potassium currents in enzymatically isolated rat skeletal muscle fibers using the double vaseline gap voltage clamp technique. RESULTS: Thymol suppressed both Ca and K currents in a concentration-dependent manner, the EC(50 )values were 193 ± 26 and 93 ± 11 μM, with Hill coefficients of 2.52 ± 0.29 and 1.51 ± 0.18, respectively. Thymol had a biphasic effect on Ca current kinetics: time to peak current and the time constant for inactivation increased at lower (100–200 μM) but decreased below their control values at higher (600 μM) concentrations. Inactivation of K current was also significantly accelerated by thymol (200–300 μM). These effects of thymol developed rapidly and were partially reversible. In spite of the marked effects on the time-dependent properties, thymol caused no change in the current-voltage relationship of Ca and K peak currents. CONCLUSIONS: Present results revealed marked suppression of Ca and K currents in skeletal muscle, similar to results obtained previously in cardiac cells. Furthermore, it is possible that part of the suppressive effects of halothane on Ca and K currents, observed experimentally, may be attributed to the concomitant presence of thymol in the superfusate

Antiarrhythmic and Inotropic Effects of Selective Na+/Ca2+ Exchanger Inhibition: What Can We Learn from the Pharmacological Studies?

Life-long stable heart function requires a critical balance of intracellular Ca2+. Several ion channels and pumps cooperate in a complex machinery that controls the influx, release, and efflux of Ca2+. Probably one of the most interesting and most complex players of this crosstalk is the Na+/Ca2+ exchanger, which represents the main Ca2+ efflux mechanism; however, under some circumstances, it can also bring Ca2+ into the cell. Therefore, the inhibition of the Na+/Ca2+ exchanger has emerged as one of the most promising possible pharmacological targets to increase Ca2+ levels, to decrease arrhythmogenic depolarizations, and to reduce excessive Ca2+ influx. In line with this, as a response to increasing demand, several more or less selective Na+/Ca2+ exchanger inhibitor compounds have been developed. In the past 20 years, several results have been published regarding the effect of Na+/Ca2+ exchanger inhibition under various circumstances, e.g., species, inhibitor compounds, and experimental conditions; however, the results are often controversial. Does selective Na+/Ca2+ exchanger inhibition have any future in clinical pharmacological practice? In this review, the experimental results of Na+/Ca2+ exchanger inhibition are summarized focusing on the data obtained by novel highly selective inhibitors

Late Sodium Current Inhibitors as Potential Antiarrhythmic Agents

Based on recent findings, an increased late sodium current (INa,late) plays an important pathophysiological role in cardiac diseases, including rhythm disorders. The article first describes what is INa,late and how it functions under physiological circumstances. Next, it shows the wide range of cellular mechanisms that can contribute to an increased INa,late in heart diseases, and also discusses how the upregulated INa,late can play a role in the generation of cardiac arrhythmias. The last part of the article is about INa,late inhibiting drugs as potential antiarrhythmic agents, based on experimental and preclinical data as well as in the light of clinical trials

Methodology of the health economic evaluation of the Feel4Diabetes-study

Background: The clinical and economic burden of type 2 diabetes mellitus on society is rising. Effective and efficient preventive measures may stop the increasing prevalence, given that type 2 diabetes mellitus is mainly a lifestyle-driven disease. The Feel4Diabetes-study aimed to tackle unhealthy lifestyle (unhealthy diet, lack of physical activity, sedentary behaviour, and excess weight) of families with a child in the first grades of elementary school. These schools were located in regions with a relatively low socio-economic status in Belgium, Bulgaria, Finland, Greece, Hungary and Spain. Special attention was paid to families with a high risk of developing type 2 diabetes mellitus. Methods: The aim of this paper is to describe the detailed methodology of the intervention’s cost-effectiveness analysis. Based on the health economic evaluation of the Toybox-study, both a decision analytic part and a Markov model have been designed to assess the long-term (time horizon of 70 year with one-year cycles) intervention’s value for money. Data sources used for the calculation of health state incidences, transition probabilities between health states, health state costs, and health state utilities are listed. Intervention-related costs were collected by questionnaires and diaries, and attributed to either all families or high risk families only. Conclusions: The optimal use of limited resources is pivotal. The future results of the health economic evaluation of the Feel4Diabetes-study will contribute to the efficient use of those resources.Publication of this supplement was funded by the European Union’s Horizon 2020 research and innovation programme under grant agreement n° 643708

The effect of a cluster-randomized controlled trial on lifestyle behaviors among families at risk for developing type 2 diabetes across Europe: the Feel4Diabetes-study

Background: This study investigated the effect of the Feel4Diabetes-intervention, a 2-year multilevel intervention, on energy balance-related behaviors among European families at risk for developing type 2 diabetes. Intervention effects on self-reported physical activity, sedentary behavior and eating behaviors were investigated across and within the participating countries: Belgium, Finland, Greece, Spain, Hungary and Bulgaria. Methods: Families were recruited through schools, located in low socio-economic status areas. In total, 4484 families at risk for developing type 2 diabetes were selected using the FINDRISC-questionnaire. Parents’ and children’s energy balance-related behaviors data were collected by questionnaires at three time points (baseline, mid- and post intervention). Families assigned to the intervention group were invited to participate in a 2-year school-, community-, and family-based intervention to promote a healthier lifestyle, including counseling sessions (first intervention year) and text messages (second intervention year). Families assigned to the control group received standard care, including medical check-up results and recommendations and tips regarding a healthy lifestyle. To assess the intervention-effects, Mixed Models were conducted using the R-Package “lmer “with R v3.2. Results: Significant intervention effects were found on a certain number of families’ lifestyle behaviors. Significant favorable intervention effects were detected on parents’ water consumption and consumption of fruit and vegetables, and on children’s consumption of sweets and moderate-to-vigorous physical activity. Analyses by country revealed significant favorable intervention effects on water consumption and on moderate-to-vigorous physical activity in Belgian parents and on fruit and vegetable consumption among Belgian children, on sweets consumption among Spanish parents and children, and on moderate-to-vigorous physical activity among Finnish children. Unfavorable intervention effects were found on the consumption of soft drinks and sugar-containing juices among Hungarian children and parents, while when examining the intervention effects for the overall population and per country, 10 from the 112 investigated outcome variables were improved in the intervention group compared to the control group (9%). Conclusions: The Feel4Diabetes-intervention managed to improve a certain number of targeted lifestyle behaviors while the intervention was not effective on a large number of targeted lifestyle behaviors. The findings of the current study are encouraging, but further research is needed on how we can further improve effectiveness of lifestyle interventions to prevent type 2 diabetes in families at risk. Trial registration: The Feel4Diabetes-study is registered with the clinical trials registry http://clinicaltrials.gov, ID: 643708. © 2021, The Author(s)

Selective Inhibition of Cardiac Late Na+ Current Is Based on Fast Offset Kinetics of the Inhibitor

The present study was designed to test the hypothesis that the selectivity of blocking the late Na+ current (INaL) over the peak Na+ current (INaP) is related to the fast offset kinetics of the Na+ channel inhibitor. Therefore, the effects of 1 µM GS967 (INaL inhibitor), 20 µM mexiletine (I/B antiarrhythmic) and 10 µM quinidine (I/A antiarrhythmic) on INaL and INaP were compared in canine ventricular myocardium. INaP was estimated as the maximum velocity of action potential upstroke (V+max). Equal amounts of INaL were dissected by the applied drug concentrations under APVC conditions. The inhibition of INaL by mexiletine and quinidine was comparable under a conventional voltage clamp, while both were smaller than the inhibitory effect of GS967. Under steady-state conditions, the V+max block at the physiological cycle length of 700 ms was 2.3% for GS967, 11.4% for mexiletine and 26.2% for quinidine. The respective offset time constants were 110 ± 6 ms, 456 ± 284 ms and 7.2 ± 0.9 s. These results reveal an inverse relationship between the offset time constant and the selectivity of INaL over INaP inhibition without any influence of the onset rate constant. It is concluded that the selective inhibition of INaL over INaP is related to the fast offset kinetics of the Na+ channel inhibitor

Do physical activity and screen time mediate the association between European fathers' and their children's weight status? Cross-sectional data from the Feel4Diabetes-study

BACKGROUND: Most research on parenting and childhood obesity and obesity-related behaviours has focused on mothers while fathers have been underrepresented. Yet, recent literature has suggested that fathers uniquely influence their children''s lifestyle behaviours, and hence could also affect their weight status, but this has not yet been scientifically proven. Therefore, the present study aimed to determine whether the association between fathers'' weight status and their children''s weight status is mediated by fathers'' and children''s movement behaviours (i.e. physical activity (PA) and screen time (ST)). METHODS: Cross-sectional data of 899 European fathers and their children were analyzed. Fathers/male caregivers (mean age =¿43.79¿±¿5.92¿years, mean BMI =¿27.08¿±¿3.95) completed a questionnaire assessing their own and their children''s (mean age =¿8.19¿±¿0.99¿years, 50.90% boys, mean BMIzscore =¿0.44¿±¿1.07) movement behaviours. Body Mass Index (BMI, in kg/m2) was calculated based on self-reported (fathers) and objectively measured (children) height and weight. For children, BMI z-scores (SD scores) were calculated to obtain an optimal measure for their weight status. Serial mediation analyses were performed using IBM SPSS 25.0 Statistics for Windows to test whether the association between fathers'' BMI and children''s BMI is mediated by fathers'' PA and children''s PA (model 1) and fathers'' ST and children''s ST (model 2), respectively. RESULTS: The present study showed a (partial) mediation effect of fathers'' PA and children''s PA (but not father''s ST and children''s ST) on the association between fathers'' BMI and children''s BMI (model for PA; coefficient: 0.001, 95% CI: [0.0001, 0.002]; model for ST; coefficient: 0.001, 95% CI: [0.000, 0.002]). Furthermore, fathers'' movement behaviours (PA and ST) were positively associated with their children''s movement behaviours (PA and ST) (model for PA, coefficient: 0.281, SE: 0.023, p <¿0.001; model for ST, coefficient: 0.345, SE: 0.025, p¿<¿0.001). CONCLUSIONS: These findings indicate that the influence of fathers on their children''s weight status partially occurs through the association between fathers'' PA and children''s PA (but not their ST). As such, intervening by focusing on PA of fathers but preferably of both members of the father-child dyad (e.g. engaging fathers and their children in co-PA) might be a novel and potentially effective strategy for interventions aiming to prevent childhood overweight and obesity. Longitudinal studies or intervention studies confirming these findings are however warranted to make meaningful recommendations for health intervention and policy. TRIAL REGISTRATION: The Feel4Diabetes-study is registered with the clinical trials registry http://clinicaltrials.gov , ID: 643708