An Observational Study on the Pharmacokinetics of Oseltamivir in Lactating Influenza Patients.

Influenza infection may lead to serious complications in the postpartum period, therefore, oseltamivir treatment in these patients and their breastfed infants is of great importance. However, the pharmacokinetics of oseltamivir in postpartum lactating women with acute influenza infection, and the consequent infant exposure to oseltamivir are still unknown, and these data would help in assessing risk and the need for dose adjustment in breastfed infants. Six lactating women with influenza-like symptoms, at a standard dose of 75 mg oral oseltamivir twice daily for 5 days, were recruited in this phase IV clinical study during the 2011/2012 H1N1 pandemic seasons. Breast milk/colostrum and venous blood samples were taken at multiple timepoints, maternal urine samples were obtained from total output within the 12-hour observational period following the seventh dose of oseltamivir. Oseltamivir phosphate (OP) reached a maximum 69.5 ± 29.4 ng/mL concentration in breast milk, higher than that found in the plasma, and showed elimination within ~ 8 hours. Oseltamivir carboxylate (active metabolite of OP) showed a lower, nearly steady-state concentration in breast milk during the observational period (maximum plasma concentration (Cmax ) = 38.4 ± 12.9 ng/mL). Based on estimated daily milk consumption of exclusively breastfed infants, their calculated daily exposure is < 0.1% of the infant dose of oseltamivir for treatment of influenza as per marketing authorization. Here, we provide the first maternal breast milk pharmacokinetic data for oral multiple-dose oseltamivir in lactating patients with influenza and showed that its concentration in the breast milk is not sufficient to reach a therapeutic dose for breastfed infants.

Droplet Digital PCR Is a Novel Screening Method Identifying Potential Cardiac G-Protein-Coupled Receptors as Candidate Pharmacological Targets in a Rat Model of Pressure-Overload-Induced Cardiac Dysfunction.

The identification of novel drug targets is needed to improve the outcomes of heart failure (HF). G-protein-coupled receptors (GPCRs) represent the largest family of targets for already approved drugs, thus providing an opportunity for drug repurposing. Here, we aimed (i) to investigate the differential expressions of 288 cardiac GPCRs via droplet digital PCR (ddPCR) and bulk RNA sequencing (RNAseq) in a rat model of left ventricular pressure-overload; (ii) to compare RNAseq findings with those of ddPCR; and (iii) to screen and test for novel, translatable GPCR drug targets in HF. Male Wistar rats subjected to transverse aortic constriction (TAC, n = 5) showed significant systolic dysfunction vs. sham operated animals (SHAM, n = 5) via echocardiography. In TAC vs. SHAM hearts, RNAseq identified 69, and ddPCR identified 27 significantly differentially expressed GPCR mRNAs, 8 of which were identified using both methods, thus showing a correlation between the two methods. Of these, Prostaglandin-F2α-receptor (Ptgfr) was further investigated and localized on cardiomyocytes and fibroblasts in murine hearts via RNA-Scope. Antagonizing Ptgfr via AL-8810 reverted angiotensin-II-induced cardiomyocyte hypertrophy in vitro. In conclusion, using ddPCR as a novel screening method, we were able to identify GPCR targets in HF. We also show that the antagonism of Ptgfr could be a novel target in HF by alleviating cardiomyocyte hypertrophy.

Effects of Bempedoic Acid in Acute Myocardial Infarction in Rats: No Cardioprotection and No Hidden Cardiotoxicity.

Lipid-lowering drugs have been shown to have cardioprotective effects but may have hidden cardiotoxic properties. Therefore, here we aimed to investigate if chronic treatment with the novel lipid-lowering drug bempedoic acid (BA) exerts hidden cardiotoxic and/or cardioprotective effects in a rat model of acute myocardial infarction (AMI). Wistar rats were orally treated with BA or its vehicle for 28 days, anesthetized and randomized to three different groups (vehicle + ischemia/reperfusion (I/R), BA + I/R, and positive control vehicle + ischemic preconditioning (IPC)) and subjected to cardiac 30 min ischemia and 120 min reperfusion. IPC was performed by 3 × 5 min I/R cycles before ischemia. Myocardial function, area at risk, infarct size and arrhythmias were analyzed. Chronic BA pretreatment did not influence cardiac function or infarct size as compared to the vehicle group, while the positive control IPC significantly reduced the infarct size. The incidence of reperfusion-induced arrhythmias was significantly reduced by BA and IPC. This is the first demonstration that BA treatment does not show cardioprotective effect although moderately reduces the incidence of reperfusion-induced arrhythmias. Furthermore, BA does not show hidden cardiotoxic effect in rats with AMI, showing its safety in the ischemic/reperfused heart.

Systematic transcriptomic and phenotypic characterization of human and murine cardiac myocyte cell lines and primary cardiomyocytes reveals serious limitations and low resemblances to adult cardiac phenotype.

BACKGROUND: Cardiac cell lines and primary cells are widely used in cardiovascular research. Despite increasing number of publications using these models, comparative characterization of these cell lines has not been performed, therefore, their limitations are undetermined. We aimed to compare cardiac cell lines to primary cardiomyocytes and to mature cardiac tissues in a systematic manner. METHODS AND RESULTS: Cardiac cell lines (H9C2, AC16, HL-1) were differentiated with widely used protocols. Left ventricular tissue, neonatal primary cardiomyocytes, and human induced pluripotent stem cell-derived cardiomyocytes served as reference tissue or cells. RNA expression of cardiac markers (e.g. Tnnt2, Ryr2) was markedly lower in cell lines compared to references. Differentiation induced increase in cardiac- and decrease in embryonic markers however, the overall transcriptomic profile and annotation to relevant biological processes showed consistently less pronounced cardiac phenotype in all cell lines in comparison to the corresponding references. Immunocytochemistry confirmed low expressions of structural protein sarcomeric alpha-actinin, troponin I and caveolin-3 in cell lines. Susceptibility of cell lines to sI/R injury in terms of viability as well as mitochondrial polarization differed from the primary cells irrespective of their degree of differentiation. CONCLUSION: Expression patterns of cardiomyocyte markers and whole transcriptomic profile, as well as response to sI/R, and to hypertrophic stimuli indicate low-to-moderate similarity of cell lines to primary cells/cardiac tissues regardless their differentiation. Low resemblance of cell lines to mature adult cardiac tissue limits their potential use. Low translational value should be taken into account while choosing a particular cell line to model cardiomyocytes.