Hormonal Regulation of BCRP Expression in Human Placental BeWo Cells

Purpose We investigated whether the pregnancy-related hormones, estriol (E₃), testosterone, human placental lactogen (hPL), human prolactin (hPRL), and human chorionic gonadotropin (hCG) affect BCRP expression in human placental BeWo cells. Materials and Methods The effects of these hormones on BCRP protein and mRNA expression in BeWo cells were determined by immunoblotting and quantitative real-time RT-PCR, respectively. The effects of these hormones on membrane localization of BCRP in BeWo cells were examined by immunofluorescent confocal microscopy. Results E₃, hPL, and hPRL significantly increased BCRP protein and mRNA approximately two to threefold at physiological concentrations. Induction of BCRP by E₃ was abrogated by the estrogen receptor (ER) antagonist ICI-182,780. However, knock-down of ERα by RNA interference did not abolish the inductive effect of E₃. Testosterone by itself did not affect BCRP expression at physiological concentrations. However, testosterone together with 17β-estradiol (E₂) increased BCRP protein and mRNA approximately twofold, and this induction was abolished by ICI-182,780 or the testosterone receptor (TR) antagonist flutamide or knock-down of ERα expression. Further analysis revealed that E₂ increased TR mRNA approximately 5.9-fold, suggesting that testosterone in combination with E₂ increases BCRP expression, possibly through E₂-mediated up-regulation of TR. hCG at physiological concentrations had no effect on BCRP expression. Conclusions E₃, hPL, hPRL, and testosterone in combination with E₂ may up-regulate BCRP expression in the placenta during pregnancy.     

The Utilization of Regional Anesthesia Among Pediatric Patients: A Retrospective Study

Background

The use of regional anesthesia (RA) in pediatric patients remains understudied, although evidence suggests benefits over general anesthesia.

Questions/Purposes

We sought to identify factors associated with RA use in patients under the age of 21 years undergoing ambulatory orthopedic surgery.

Methods

Patients under the age of 21 who underwent anterior cruciate ligament (ACL) repair or reconstruction, knee arthroscopy (KA), or shoulder arthroscopy (SA) were identified from the NY Statewide Planning and Research Cooperative System (SPARCS) database (2005–2015). Frequencies of RA use (defined by femoral nerve block, spinal, epidural, caudal, or brachial plexus anesthesia) were calculated. Multivariable regression analysis identified patient- and healthcare system–related factors associated with the use of RA. Odds ratios (OR) and 95% confidence intervals (CI) were reported.

Results

We identified 87,273 patients who underwent the procedures of interest (ACL n = 28,226; SA n = 18,155; KA n = 40,892). In our primary analysis, 14.4% (n = 1404) had RA as their primary anesthetic; this percentage increased for patients who had ACL or KA. When adjusting for covariates, Hispanic ethnicity (OR 0.78; CI 0.65–0.94) and Medicaid insurance (OR 0.75; CI 0.65–0.87) were associated with decreased odds for the provision of RA. Further, we identified increasing age (OR 1.10; CI 1.08–1.11), ACL versus SA (OR 1.91; CI 1.74–2.10), and sports injuries (OR 1.20; CI 1.10–1.31) as factors associated with increased odds of RA use.

Conclusion

In this analysis, RA was used in a minority of patients under the age of 21 undergoing ambulatory orthopedic surgery. Older age was associated with increased use while Hispanic ethnicity and lower socioeconomic status were associated with lower use.

     

Pharmacokinetics and safety of indinavir in human immunodeficiency virus-infected pregnant women

Human immunodeficiency virus-infected women (n=16) received indinavir (800 mg three times a day) plus zidovudine plus lamivudine from 14 to 28 weeks of gestation to 12 weeks postpartum. Two women and eight infants experienced grade 3 or 4 toxicities that were possibly treatment related. Indinavir area under the plasma concentration-time curve was 68% lower antepartum versus postpartum, suggesting increased intestinal and/or hepatic CYP3A activity during pregnancy.     

Preoperative Patient-Reported Outcomes and Clinical Characteristics as Predictors of 90-Day Cost/Utilization and Complications

Background

With the advent of mandatory bundle payments for total joint arthroplasty (TJA), assessing patients’ risk for increased 90-day complications and resource utilization is crucial. This study assesses the degree to which preoperative patient-reported outcomes predict 90-day complications, episode costs, and utilization in TJA patients.

Role of the equilibrative and concentrative nucleoside transporters in the intestinal absorption of the nucleoside drug, ribavirin, in wild-type and ent1(-/-) mice

Ribavirin is frontline treatment for hepatitis C virus infection. To determine the role of nucleoside transporters in the intestinal absorption of orally administered ribavirin, we perfused the intestines of Ent1(-/-) and wild-type mice, in situ, with [(3)H] ribavirin (20, 200, and 5000 μM) in the presence and absence of sodium. The decrease in luminal ribavirin concentration over 30 min was measured at 5 min intervals. Blood samples were collected approximately every 10 min. Ribavirin plus phosphorylated metabolite concentrations (hereafter referred to as ribavirin) were determined in tissue, blood, and plasma by HPLC fractionation and scintillation counting. There was no significant difference between wild-type and Ent1(-/-) mice in intestinal loss of ribavirin at any ribavirin concentration studied. Perfusions without sodium drastically reduced the intestinal loss of ribavirin in both wild-type and Ent1(-/-) mice. After 20 μM ribavirin perfusions, Ent1(-/-) intestinal tissue contained 8-fold greater ribavirin than wild-type mice (p < 0.01). Ribavirin concentrations in the wild-type intestinal tissue were 70-fold higher after 200 vs 20 μM perfusions (p < 0.001), indicating saturation of intestinal ribavirin efflux and possibly other processes as well. Ribavirin plasma concentrations were significantly higher in wild-type mice (2.7-fold) vs Ent1(-/-) mice at 30 min after the 20 μM perfusion (p < 0.01). These results suggest that, at lower intestinal concentrations of ribavirin, concentrative and equilibrative nucleoside transporters are important in the intestinal absorption of ribavirin. At higher intestinal concentrations, these transporters are saturated and other processes in the intestine (transport and/or metabolism) play an important role in the absorption of ribavirin.     

Interindividual Variability in the Hepatic Expression of the Human Breast Cancer Resistance Protein (BCRP/ABCG2): Effect of Age,Sex, and Genotype

Breast cancer resistance protein (BCRP), an efflux transporter expressed at the bile canalicular membrane, is responsible for the biliary clearance of many drugs. Data on the interindividual variability of hepatic BCRP expression are needed for in vitro to in vivo extrapolation of the biliary clearance of a BCRP substrate drug. Therefore, we measured the expression of BCRP in human livers (n = 65) by liquid chromatography coupled with tandem mass spectrometry. A calibration curve was generated using a synthetic signature peptide (SSLLDVLAAR) as the calibrator and the corresponding synthetic stable isotope-labeled peptide as the internal standard. The analytical method was accurate and precise. BCRP expression in 50 livers, where it was measurable, was 137.9 ± 42.1 atmol/μg of membrane protein (range 69.7–246.4 atmol/μg of membrane protein). BCRP expression was not associated with age (7–70 years), sex, or mRNA expression. BCRP expression in livers with the variant C421A (rs2231142) allele (14 heterozygotes, two homozygotes; among these, eight livers were below lower limit of quantification) was significantly lower than that in the wild-type livers (p < 0.002). Integration of these data with data on the hepatic expression of other transporters will allow refinement of physiologically based pharmacokinetic models to predict the pharmacokinetics, hepatic exposure, and drug-drug interactions of drugs (and/or their metabolites). © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 102:787–793, 2013