Development of coronary dysfunction in adult progeny after maternal engineered nanomaterial inhalation during gestation

Maternal exposure to environmental contaminants during pregnancy can profoundly influence the risk of developing cardiovascular disease in adult offspring. Our previous studies have demonstrated impaired cardiovascular health, microvascular reactivity, and cardiac function in fetal and young adult progeny after maternal inhalation of nano-sized titanium dioxide (nano-TiO2) aerosols during gestation. The present study was designed to evaluate the development of cardiovascular and metabolic diseases later in adulthood. Pregnant Sprague-Dawley rats were exposed to nano-TiO2 aerosols (similar to 10 mg/m(3), 134 nm median diameter) for 4 h per day, 5 days per week, beginning on gestational day (GD) 4 and ending on GD 19. Progeny were delivered in-house. Body weight was recorded weekly after birth. After 47 weeks, the body weight of exposed progeny was 9.4% greater compared with controls. Heart weight, mean arterial pressure, and plasma biomarkers of inflammation, dyslipidemia, and glycemic control were recorded at 3, 9 and 12 months of age, with no significant adaptations. While no clinical risk factors (i.e., hypertension, dyslipidemia, or systemic inflammation) emerged pertaining to the development of cardiovascular disease, we identified impaired endothelium-dependent and -independent arteriolar dysfunction and cardiac morphological alterations consistent with myocardial inflammation, degeneration, and necrosis in exposed progeny at 12 months. In conclusion, maternal inhalation of nano-TiO2 aerosols during gestation may promote the development of coronary disease in adult offspring

The Hepatitis B Virus Ribonuclease H Is Sensitive to Inhibitors of the Human Immunodeficiency Virus Ribonuclease H and Integrase Enzymes

Nucleos(t)ide analog therapy blocks DNA synthesis by the hepatitis B virus (HBV) reverse transcriptase and can control the infection, but treatment is life-long and has high costs and unpredictable long-term side effects. The profound suppression of HBV by the nucleos(t)ide analogs and their ability to cure some patients indicates that they can push HBV to the brink of extinction. Consequently, more patients could be cured by suppressing HBV replication further using a new drug in combination with the nucleos(t)ide analogs. The HBV ribonuclease H (RNAseH) is a logical drug target because it is the second of only two viral enzymes that are essential for viral replication, but it has not been exploited, primarily because it is very difficult to produce active enzyme. To address this difficulty, we expressed HBV genotype D and H RNAseHs in E. coli and enriched the enzymes by nickel-affinity chromatography. HBV RNAseH activity in the enriched lysates was characterized in preparation for drug screening. Twenty-one candidate HBV RNAseH inhibitors were identified using chemical structure-activity analyses based on inhibitors of the HIV RNAseH and integrase. Twelve anti-RNAseH and anti-integrase compounds inhibited the HBV RNAseH at 10 μM, the best compounds had low micromolar IC50 values against the RNAseH, and one compound inhibited HBV replication in tissue culture at 10 μM. Recombinant HBV genotype D RNAseH was more sensitive to inhibition than genotype H. This study demonstrates that recombinant HBV RNAseH suitable for low-throughput antiviral drug screening has been produced. The high percentage of compounds developed against the HIV RNAseH and integrase that were active against the HBV RNAseH indicates that the extensive drug design efforts against these HIV enzymes can guide anti-HBV RNAseH drug discovery. Finally, differential inhibition of HBV genotype D and H RNAseHs indicates that viral genetic variability will be a factor during drug development. © 2013 Tavis et al

Pregnancy Represses Induction of Efflux Transporters in Livers of Type I Diabetic Mice

Purpose: To determine whether down-regulation of transcription factor signaling during pregnancy disrupts the induction of efflux transporters in type I diabetic mice. Methods: Type I diabetes was induced in female C57BL/6 mice with multiple low dose intraperitoneal injections of streptozotocin (STZ) at least 2 weeks prior to mating with normoglycemic male mice. On gestation day 14, livers were collected from vehicle- and STZ-treated non-pregnant and pregnant mice for quantification of efflux transporter and transcription factor signaling. Results: STZ treatment up-regulated expression of Mrp1-5, Mdr1, Abcg5, Abcg8, Bcrp, and Bsep mRNA and/or protein in the livers of non-pregnant mice. Interestingly, little to no change in transporter expression was observed in STZ-treated pregnant mice compared to vehicle- and STZ-treated non-pregnant mice. Conclusions: This study demonstrates the opposing regulation of hepatobiliary efflux transporters in response to diabetes and pregnancy and points to PPARγ, Nrf2, and FXR as candidate pathways underlying the differential expression of transporters

Acquired Resistance to Acetaminophen Hepatotoxicity is Associated with Induction of Multidrug Resistance-Associated Protein 4 (Mrp4) in Proliferating Hepatocytes

Treatment with hepatotoxicants such as acetaminophen (APAP) causes resistance to a second, higher dose of the same toxicant (autoprotection). APAP induces hepatic mRNA and protein levels of the multidrug resistance-associated proteins (Mrp) transporters in mice and humans. Basolateral efflux transporters Mrp3 and Mrp4 are the most significantly induced. We hypothesized that upregulation of Mrp3 and Mrp4 is one mechanism by which hepatocytes become resistant to a subsequent higher dose of APAP by limiting accumulation of xeno-, endobiotics, and byproducts of hepatocellular injury. The purpose of this study was to evaluate Mrp3 and Mrp4 expression in proliferating hepatocytes in a mouse model of APAP autoprotection. Plasma and livers were collected from male C57BL/6J mice treated with APAP 400 mg/kg for determination of hepatotoxicity and protein expression. Maximal Mrp3 and Mrp4 induction occurred 48 h after APAP. Mrp4 upregulation occurred selectively in proliferating hepatocytes. Additional groups of APAP-pretreated mice were challenged 48 h later with a second, higher dose of APAP. APAP-pretreated mice had reduced hepatotoxicity after APAP challenge compared to those pretreated with vehicle. A more rapid recovery of glutathione (GSH) in APAP-pretreated mice corresponded with increases in GSH synthetic enzymes. Interestingly, mice pretreated and challenged with APAP had dramatic increases in Mrp4 expression as well as enhanced hepatocyte proliferation. Inhibition of hepatocyte replication with colchicine not only restored sensitivity of APAP-pretreated mice to injury, but also blocked Mrp4 induction. Mrp4 overexpression may be one phenotypic property of proliferating hepatocytes that protects against subsequent hepatotoxicant exposure by mechanisms that are presently unknown

In vivo cytochrome P450 activity alterations in diabetic nonalcoholic steatohepatitis mice

Nonalcoholic steatohepatitis (NASH) has been identified as a source of significant inter individual variation in drug metabolism. A previous ex vivo study demonstrated significant changes in hepatic Cytochrome P450 (CYP) activity in human NASH. This study evaluated the in vivo activities of multiple CYP isoforms simultaneously in prominent diabetic NASH mouse models. The pharmacokinetics of CYP selective substrates: caffeine, losartan, and omeprazole changed significantly in a diabetic NASH mouse model, indicating attenuation of the activity of Cyp1a2 and Cyp2c29, respectively. Decreased mRNA expression of Cyp1a2 and Cyp2c29, as well as an overall decrease in CYP protein expression, was found in the diabetic NASH mice. Overall, these data suggest that the diabetic NASH model only partially recapitulates the human ex vivo CYP alteration pattern. Therefore, in vivo determination of the effects of NASH on CYP activity should be conducted in human, and more appropriate models are required for future drug metabolism studies in NASH.National Institutes of Health [ES006694, HD062489]; National Institute of Environmental Health Science. Toxicology Training Grant [ES007091]12 month embargo; Version of record online: 6 October 2016This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Compensatory Induction of Liver Efflux Transporters in Response to ANIT-Induced Liver Injury Is Impaired in FXR-Null Mice

Alpha-naphthyl isothiocyanate (ANIT) is a hepatotoxicant that produces acute intrahepatic cholestasis in rodents. Farnesoid X receptor (FXR) and pregnane X receptor (PXR) are two major bile acid sensors in liver. The purpose of this study was to characterize the regulation of hepatic transporters by FXR and PXR during ANIT-induced liver injury. Wild-type, FXR-null, and PXR-null mice were administered ANIT (75 mg/kg, po) and evaluated 48 h later for hepatotoxicity and messenger RNA (mRNA) expression of basolateral uptake (sodium taurocholate–cotransporting polypeptide, organic anion transporting polypeptide [Oatp] 1a1, Oatp1a4, Oatp1b2) and efflux transporters (organic solute transporter [Ost] α, Ostβ, multidrug resistance–associated protein [Mrp] 3, Mrp4), as well as canalicular transporters (bile salt export pump [Bsep], Mrp2, multidrug resistance protein 2 [Mdr2], ATPase, class I, type 8B, member 1 [Atp8b1]). Livers from wild-type and PXR-null mice had comparable multifocal necrosis 48 h after ANIT. However, ANIT-treated FXR-null mice have fewer and smaller necrotic foci than wild-type mice but had scattered single-cell hepatocyte necrosis throughout the liver. Serum alanine transaminase, alkaline phosphatase (ALP), and direct bilirubin were increased in all genotypes, with higher ALP levels in FXR-null mice. Serum and liver unconjugated bile acids were higher in ANIT-treated FXR-null mice than the other two genotypes. ANIT induced mRNA expression of Mdr2, Bsep, and Atp8b1 in wild-type and PXR-null mice but failed to upregulate these genes in FXR-null mice. mRNA expression of uptake transporters declined in livers of all genotypes following ANIT treatment. ANIT increased Ostβ and Mrp3 mRNA in livers of wild-type and PXR-null mice but did not alter Ostβ mRNA in FXR-null mice. In conclusion, FXR deficiency enhances susceptibility of mice to ANIT-induced liver injury, likely a result of impaired induction of hepatobiliary efflux transporters and subsequent hepatic accumulation of unconjugated bile acids

Medication-Related Problems Identified Through Continuous Medication Monitoring

Community pharmacists performing Continuous Medication Monitoring (CoMM) systematically monitor each new prescription and refill dispensed for medication-related problems. The objectives for this study were to describe medication-related problems identified through CoMM and drug classes involved in problems. This 12-month pilot study used dispensing and clinical records from a single independent U.S. community pharmacy. Clinical records contain medication-related problems documented by the pharmacists. Problems identified for patients filling at least one prescription at the pharmacy and having at least one medication-related problem during the study period were included. A total of 8439 medication-related problems were identified for 1566 patients, an average of 5.4 problems per patient. Over 63% of problems were nonadherence. The drug class most often involved in problems was the central nervous system and analgesic class. Community pharmacists performing CoMM identified medication-related problems that might otherwise have gone undetected

Role of nuclear factor-erythroid 2-related factor 2 (Nrf2) in the transcriptional regulation of brain ABC transporters during acute acetaminophen (APAP) intoxication in mice

Changes in expression of liver ABC transporters have been described during acute APAP intoxication. However, the effect of APAP on brain ABC transporters is poorly understood. The aim of this study was to evaluate the effect of APAP on brain ABC transporters expression and the role of the oxidative stress sensor Nrf2. Male C57BL/6J mice were administered APAP (400 mg/kg) for analysis of brain mRNA and protein expression of Mrp1-6, Bcrp and P-gp. The results show induction of P-gp, Mrp2 and Mrp4 proteins, with no changes in Bcrp, Mrp1 or Mrp5-6. The protein values were accompanied by corresponding changes in mRNA levels. Additionally, brain Nrf2 nuclear translocation and expression of two Nrf2 target genes, NAD(P)H:quinone oxidoreductase 1 (Nqo1) and Hemoxygenase 1 (Ho-1), was evaluated at 6, 12 and 24 h after APAP treatment. Nrf2 nuclear content increased by 58% at 12 h after APAP along with significant increments in mRNA and protein expression of Nqo1 and Ho-1. Furthermore, APAP treated Nrf2 knockout mice did not increase mRNA or protein expression of Mrp2 and Mrp4 as observed in wildtypes. In contrast, P-gp induction by APAP was observed in both genotypes. In conclusion, acute APAP intoxication induces protein expression of brain P-gp, Mrp2 and Mrp4. This study also suggests that brain changes in Mrp2 and Mrp4 expression may be due to in situ Nrf2 activation by APAP, while P-gp induction is independent of Nrf2 function. The functional consequences of these changes in brain ABC transporters by APAP deserve further attention.Fil: Ghanem, Carolina Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Farmacológicas (i); Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Rudraiah, Swetha. University Of Connecticut; Estados UnidosFil: Bataille, Amy M.. University Of Connecticut; Estados UnidosFil: Vigo, María B.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Farmacológicas (i); Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Goedken, Michael J.. Rutgers University. Office of Translational Science; Estados UnidosFil: Manautou, José E.. University Of Connecticut; Estados Unido