beta-Adrenergic stimulation

Left ventricular systolic function after inhalation of beta-2 agonists in healthy athletes

Inhaled beta-2 adrenoceptor agonists (iβ2A) are routinely used as bronchodilators in the treatment of asthma. However, their cardiac effects in athletes are scarcely examined. Thus, the aim of this study was to evaluate the effects of iβ2A on left ventricular (LV) systolic function (SF) by echocardiography in healthy, non-asthmatic female and male endurance athletes. A randomized, double-blinded, placebo-controlled, balanced, 4-way complete block cross-over study was conducted. Twenty-four healthy athletes (12f/12m: 22.9 ± 2.7/24.4 ± 4.6 years) randomly completed 4 study arms (placebo; salbutamol; formoterol; formoterol + salbutamol). After inhalation of the study medication, the participants performed a 10-min time trial (TT) on a bicycle ergometer. After each TT an echocardiography was performed to determine LVSF. Blood samples were collected pre, post, 3 h and 24 h post TT. In females, total serum concentrations for salbutamol and formoterol were higher. LV ejection fraction (LVEF) and LV global longitudinal strain (LVendoGLS) showed a treatment effect for the whole study group (p < 0.0001) and a sex effect on LVEF (p = 0.0085). In women, there was a significant treatment effect for all medication arms (at least p ≤ 0.01) both on LVEF and LVendoGLS. In men only formoterol and formoterol + salbutamol displayed a treatment effect on LVEF (p = 0.0427, p = 0.0330; respectively), whereas on LVendoGLS only formoterol + salbutamol was significant (p = 0.0473). The iβ2A significantly influenced LVSF after an acute bout of exercise in healthy endurance athletes. These effects were even more pronounced when combining both iβ2A that supports a dose-dependent effect on cardiac function. Moreover, female athletes had higher serum concentrations of β2 agonists and stronger effects on LVSF compared to male athletes. This is mainly explained by differences in body weight and related plasma volume and may indicate a potential risk when increasing dose above the tested concentrations. Trial registration: At the European Union Drug Regulating Authorities Clinical Trials (Eudra CT) with the number 201,500,559,819 (registered prospectively on 09/12/2015) and at the German register for clinical studies (DRKS number 00010574 registered retrospectively on 16/11/2021).

Mass spectrometric characterization of urinary hydrafinil metabolites for routine doping control purposes

Little information on the human metabolism and urinary elimination of hydrafinil (9-fluorenol) exists. In order to support preventive anti-doping activities concerning compounds such as hydrafinil, a pilot elimination study was conducted with three healthy male volunteers receiving a single oral dose of 50 mg of hydrafinil. Urine samples were collected prior to and up to 72-h post-administration and were subjected to both gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry, which allowed for the identification of the intact drug as well as Phase I and Phase II metabolites, primarily hydroxylated and/or glucuronidated or sulfo-conjugated hydrafinil. The identity of these metabolites was corroborated by high-resolution/high-accuracy tandem mass spectrometry, and the applicability of routine doping control workflows for the detection of hydrafinil and its main metabolites was assessed. Therefore, two findings of hydrafinil and its metabolites were recorded, which concerned out-of-competition doping control samples and, hence, were not pursued with confirmatory analyses. Yet, the initial testing procedure results indicate that hydrafinil might require consideration in sports drug testing programs to ensure its detection, if classified as prohibited by the World Anti-Doping Agency (WADA).

Synergistical action of the β2 adrenoceptor and fatty acid binding protein 2 polymorphisms on the loss of glomerular filtration rate in Chinese patients with type 2 diabetic nephropathy

PURPOSE

Since altered sympathetic nerve activity and insulin resistance are implicated in the pathogenesis of type 2 diabetic nephropathy, we investigated the effect of polymorphic Arg16Gly and Gln27Glu in the β2 adrenoceptor gene and Ala54Thr in the fatty acid binding protein 2 gene on the estimated glomerular filtration rate (eGFR) in Chinese patients with the above disease.

METHODS

A total of 552 diabetic subjects recruited from annual health examinations were studied. The eGFR was calculated from the Modification of Diet in Renal Disease equation for the Chinese. Plasma norepinephrine level and genotype were determined by high-performance liquid chromatography-tandem mass spectrometry and TaqMan method, respectively. Holter-derived heart rate viability (HRV) and the MRI-generated renal apparent diffusion coefficient (ADC) were evaluated.

RESULTS

The Gly16Gly and Thr54Thr homozygotes had significantly higher microalbuminuria and lower eGFR against other genotypes in their individual polymorphism. Besides, the Gly16Gly variant exhibited markedly elevated norepinephrine level, whereas indicative of insulin resistance was increased in the Thr54Thr one. Multiple linear regression analysis further confirmed the independent genetic effect on the eGFR. Moreover, multifactor dimensionality reduction method detected a gene-gene synergistic action that subjects with the Gly16Gly/Thr54Thr genotype were exposed to higher risk of eGFR loss. Finally, these findings were accompanied by lower HRV and ADC, indicating sympathetically mediated hemodynamic changes.

CONCLUSIONS

By uncovering the genetic component of the coherent interplay between the elevated sympathetic nerve activity and metabolic disorders, our observations might promote the development of novel personalized prevention and management strategies against the diabetic nephropathy, especially in the genetically susceptible individuals.

Current status and recent advantages in derivatization procedures in human doping control

Derivatization is one of the most important steps during sample preparation in doping control analysis. Its main purpose is the enhancement of chromatographic separation and mass spectrometric detection of analytes in the full range of laboratory doping control activities. Its application is shown to broaden the detectable range of compounds, even in LC–MS analysis, where derivatization is not a prerequisite. The impact of derivatization initiates from the stage of the metabolic studies of doping agents up to the discovery of doping markers, by inclusion of the screening and confirmation procedures of prohibited substances in athlete's urine samples. Derivatization renders an unlimited number of opportunities to advanced analyte detection.