RESUMEN
Objectives: Teicoplanin has been extensively used in the treatment for infections caused by gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA). However, current teicoplanin treatment is challenging due to relatively low and variable concentrations under standard dosage regimens. This study aimed to investigate the population pharmacokinetics (PPK) characteristics of teicoplanin in adult sepsis patients and provide recommendations for optimal teicoplanin dosing regimens. Methods: A total of 249 serum concentration samples from 59 septic patients were prospectively collected in the intensive care unit (ICU). Teicoplanin concentrations were detected, and patients' clinical data were recorded. PPK analysis was performed using a non-linear, mixed-effect modeling approach. Monte Carlo simulations were performed to evaluate currently recommended dosing and other dosage regimens. The optimal dosing regimens were defined and compared by different pharmacokinetic/pharmacodynamic parameters, including trough concentration (Cmin), the ratio of 24-h area under the concentration-time curve to the minimum inhibitory concentration (AUC0-24/MIC), as well as the probability of target attainment (PTA) and the cumulative fraction of response (CFR) against MRSA. Results: A two-compartment model adequately described the data. The final model parameter estimates for clearance, central compartment volume of distribution, intercompartmental clearance and peripheral compartment volume were 1.03 L/h, 20.1 L, 3.12 L/h and 101 L, respectively. Glomerular filtration rate (GFR) was the only covariate that significantly affected teicoplanin clearance. Model-based simulations revealed that 3 or 5 loading doses of 12/15 mg/kg every 12 h followed by a maintenance dose of 12/15 mg/kg every 24 h-72 h for patients with different renal functions were required to achieve a target Cmin of 15 mg/L and a target AUC0-24/MIC of 610. For MRSA infections, PTAs and CFRs were not satisfactory for simulated regimens. Prolonging the dosing interval may be easier to achieve the target AUC0-24/MIC than reducing the unit dose for renal insufficient patients. Conclusion: A PPK model for teicoplanin in adult septic patients was successfully developed. Model-based simulations revealed that current standard doses may result in undertherapeutic Cmin and AUC, and a single dose of at least 12 mg/kg may be needed. AUC0-24/MIC should be preferred as the PK/PD indicator of teicoplanin, if AUC estimation is unavailable, in addition to routine detection of teicoplanin Cmin on Day 4, follow-up therapeutic drug monitoring at steady-state is recommended.
RESUMEN
Objective: The present study was to determine the effects of aerobic interval training (AIT) on the expressions of SIRT1, Nox4 and inflammatory factor in the heart of rats with myocardial infarction (MI). Methods: Male Sprague Dawley rats were randomly divided into sham-operated group (C), sedentary MI group (MI) and MI with AIT group (ME) (n=10). The MI model was established by ligation the left anterior descending coronary artery. Rats in C groups were subjected to the same surgery, but only threaded and not ligated. After surgery 1 week, rats in ME groups took adaptability training for 1 week, and then subjected to 4 weeks treadmill exercise training. After training, the hearts were collected for histological observation. The level of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) in heart was assessed by ultraviolet spectrophotometry. The activity of lactate dehydrogenase (LDH) was determined by enzyme linked immunosorbent assay. The expression of sirtuin1 (SIRT1) mRNA was examined by real-time quantitative polymerase chain reaction (RT-qPCR). The protein expressions of SIRT1, NADPH oxidase 4 (Nox4), tumor necrosis factor-alpha (TNF-α) and interleukin-1ß (IL-1ß) were detected by Western blotting. The levels of reactive oxygen species (ROS) were detected by dihydroethidium (DHE) staining. Results: Compared with the C group, the expression level of cardiac Nox4 protein was increased (Pï¼0.01), the level of MDA, activity of LDH and the level of ROS were increased significantly (Pï¼0.01), and the expressions of TNF-α and IL-1ß protein were augmented in the heart of rats with MI (Pï¼0.01). However, the expressions of SIRT1 mRNA and protein and the activity of SOD were obviously decreased in MI group (Pï¼0.01). Furthermore, compared with the MI group, AIT increased the expressions of SIRT1 mRNA and protein and the activity of SOD in the heart of ME group (Pï¼0.01); Meanwhile, the expressions of cardiac Nox4, MDA level, LDH activity and ROS level were diminished in ME group (Pï¼0.01) as well as the decreased expressions of TNF-α and IL-1ß protein (Pï¼0.01). SIRT1 expression was negatively related to the expressions of NOX4 and ROS. Conclusion: AIT obviously inhibited myocardial oxidative stress and inflammatory reaction, improved cardiac function in rats with MI, and the mechanism was closely related to the activation of SIRT1-Nox4-ROS signaling pathway.