Publications by authors named "Veronica Krogstad"

8 Publications

  • Page 1 of 1

Influence of Proteome Profiles and Intracellular Drug Exposure on Differences in CYP Activity in Donor-Matched Human Liver Microsomes and Hepatocytes.

Mol Pharm 2021 04 19;18(4):1792-1805. Epub 2021 Mar 19.

Department of Pharmacy and Science for Life Laboratory, Uppsala University, 752 37 Uppsala, Sweden.

Human liver microsomes (HLM) and human hepatocytes (HH) are important systems for studies of intrinsic drug clearance (CL) in the liver. However, the CL values are often in disagreement for these two systems. Here, we investigated these differences in a side-by-side comparison of drug metabolism in HLM and HH prepared from 15 matched donors. Protein expression and intracellular unbound drug concentration (Kp) effects on the CL were investigated for five prototypical probe substrates (bupropion-CYP2B6, diclofenac-CYP2C9, omeprazole-CYP2C19, bufuralol-CYP2D6, and midazolam-CYP3A4). The samples were donor-matched to compensate for inter-individual variability but still showed systematic differences in CL. Global proteomics analysis outlined differences in HLM from HH and homogenates of human liver (HL), indicating variable enrichment of ER-localized cytochrome P450 (CYP) enzymes in the HLM preparation. This suggests that the HLM may not equally and accurately capture metabolic capacity for all CYPs. Scaling CL with CYP amounts and Kp could only partly explain the discordance in absolute values of CL for the five substrates. Nevertheless, scaling with CYP amounts improved the agreement in rank order for the majority of the substrates. Other factors, such as contribution of additional enzymes and variability in the proportions of active and inactive CYP enzymes in HLM and HH, may have to be considered to avoid the use of empirical scaling factors for prediction of drug metabolism.
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http://dx.doi.org/10.1021/acs.molpharmaceut.1c00053DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8041379PMC
April 2021

Correlation of Body Weight and Composition With Hepatic Activities of Cytochrome P450 Enzymes.

J Pharm Sci 2021 01 19;110(1):432-437. Epub 2020 Oct 19.

Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway. Electronic address:

Obesity is associated with comorbidities of which pharmacological treatment is needed. Physiological changes associated with obesity may influence the pharmacokinetics of drugs, but the effect of body weight on drug metabolism capacity remains uncertain. The aim of this study was to investigate ex vivo activities of hepatic drug metabolizing CYP enzymes in patients covering a wide range of body weight. Liver biopsies from 36 individuals with a body mass index (BMI) ranging from 18 to 63 kg/m were obtained. Individual hepatic microsomes were prepared and activities of CYP3A, CYP2B6, CYP2C8, CYP2D6, CYP2C9, CYP2C19 and CYP1A2 were determined. The unbound intrinsic clearance (CL) values for CYP3A correlated negatively with body weight (r = -0.43, p < 0.01), waist circumference (r = -0.47, p < 0.01), hip circumference (r = -0.51, p < 0.01), fat percent (r = -0.41, p < 0.05), fat mass (r = -0.48, p < 0.01) and BMI (r = -0.46, p < 0.01). Linear regression analysis showed that CL values for CYP3A decreased with 5% with each 10% increase in body weight (r = 0.12, β = -0.558, p < 0.05). There were no correlations between body weight measures and CL values for the other CYP enzymes investigated. These results indicate reduced hepatic metabolizing capacity of CYP3A substrates in patients with increasing body weight.
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http://dx.doi.org/10.1016/j.xphs.2020.10.027DOI Listing
January 2021

CbpA is a collagen binding cell surface protein under c-di-GMP control.

Cell Surf 2019 Dec 23;5:100032. Epub 2019 Aug 23.

Centre for Integrative Microbial Evolution and Section for Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Norway.

Cyclic diguanylate (c-di-GMP) signalling affects several cellular processes in group bacteria including biofilm formation and motility, and CdgF was previously identified as a diguanylate cyclase promoting biofilm formation in C-di-GMP can exert its function as a second messenger via riboswitch binding, and a functional c-di-GMP-responsive riboswitch has been found upstream of in various group strains. Protein signature recognition predicted CbpA to be a cell wall-anchored surface protein with a fibrinogen or collagen binding domain. The aim of this study was to identify the binding ligand of CbpA and the function of CbpA in cellular processes that are part of the group c-di-GMP regulatory network. By global gene expression profiling was found to be down-regulated in a deletion mutant, and exhibited maximum expression in early exponential growth. Contrary to the wild type, a deletion mutant showed no binding to collagen in a cell adhesion assay, while a CbpA overexpression strain exhibited slightly increased collagen binding compared to the control. For both fibrinogen and fibronectin there was however no change in binding activity compared to controls, and CbpA did not appear to contribute to binding to abiotic surfaces (polystyrene, glass, steel). Also, the CbpA overexpression strain appeared to be less motile and showed a decrease in biofilm formation compared to the control. This study provides the first experimental proof that the binding ligand of the c-di-GMP regulated adhesin CbpA is collagen.
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http://dx.doi.org/10.1016/j.tcsw.2019.100032DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7423583PMC
December 2019

Reply to letter: "What about drug bioavailability in patients who had bariatric surgery and dependent on immunosuppressives?"

Obes Rev 2020 02 20;21(2):e12954. Epub 2019 Nov 20.

Morbid Obesity Centre, Department of Medicine, Vestfold Hospital Trust, Tønsberg, Norway.

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http://dx.doi.org/10.1111/obr.12954DOI Listing
February 2020

A Comparative Analysis of Cytochrome P450 Activities in Paired Liver and Small Intestinal Samples from Patients with Obesity.

Drug Metab Dispos 2020 01 4;48(1):8-17. Epub 2019 Nov 4.

Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Oslo, Norway (V.K., I.R., A.Å., H.C.); Department of Transplantation Medicine, Oslo University Hospital, Rikshospitalet, Oslo, Norway (V.K., A.Å.); Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca Gothenburg, Gothenburg, Sweden (A.P., C.W., S.A., T.B.A.); Center for Psychopharmacology, Diakonhjemmet Hospital, Oslo, Norway (M.K.K.); Department of Health Sciences, OsloMet-Oslo Metropolitan University, Oslo, Norway (M.K.K.); Department of Pharmacy, Uppsala University, Uppsala, Sweden (C.W., P.A.); The Morbid Obesity Centre, Vestfold Hospital Trust, Tønsberg, Norway (P.C.A., J.H.); Department of Surgery, Vestfold Hospital Trust, Tønsberg, Norway (P.C.A.); Department of Endocrinology, Morbid Obesity and Preventive Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway (J.H.); Late-Stage Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca Gothenburg, Gothenburg, Sweden (C.K.); Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden (C.K.); and Department of Physiology and Pharmacology, Section of Pharmacogenetics, Karolinska Institutet, Stockholm, Sweden (T.B.A.).

The liver and small intestine restrict oral bioavailability of drugs and constitute the main sites of pharmacokinetic drug-drug interactions. Hence, detailed data on hepatic and intestinal activities of drug metabolizing enzymes is important for modeling drug disposition and optimizing pharmacotherapy in different patient populations. The aim of this study was to determine the activities of seven cytochrome P450 (P450) enzymes in paired liver and small intestinal samples from patients with obesity. Biopsies were obtained from 20 patients who underwent Roux-en-Y gastric bypass surgery following a 3-week low-energy diet. Individual hepatic and intestinal microsomes were prepared and specific probe substrates in combined incubations were used for determination of CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP3A activities. The activities of CYP2C8, CYP2C9, CYP2D6, and CYP3A were quantified in both human liver microsomes (HLM) and human intestinal microsomes (HIM), while the activities of CYP1A2, CYP2B6, and CYP2C19 were only quantifiable in HLM. Considerable interindividual variability was present in both HLM (9- to 23-fold) and HIM (5- to 55-fold). The median metabolic HLM/HIM ratios varied from 1.5 for CYP3A to 252 for CYP2C8. The activities of CYP2C9 in paired HLM and HIM were positively correlated ( = 0.74, < 0.001), while no interorgan correlations were found for activities of CYP2C8, CYP2D6, and CYP3A ( > 0.05). Small intestinal CYP3A activities were higher in females compared with males ( < 0.05). Hepatic CYP2B6 activity correlated negatively with body mass index ( = -0.72, < 0.001). These data may be useful for further in vitro-in vivo predictions of drug disposition in patients with obesity. SIGNIFICANCE STATEMENT: Hepatic and intestinal drug metabolism is the key determinant of oral drug bioavailability. In this study, paired liver and jejunum samples were obtained from 20 patients with obesity undergoing gastric bypass surgery following a 3-week low-energy diet. We determined the hepatic and small intestinal activities of clinically important P450 enzymes and provide detailed enzyme kinetic data relevant for predicting in vivo disposition of P450 substrates in this patient population.
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http://dx.doi.org/10.1124/dmd.119.087940DOI Listing
January 2020

The influence of bariatric surgery on oral drug bioavailability in patients with obesity: A systematic review.

Obes Rev 2019 09 24;20(9):1299-1311. Epub 2019 Jun 24.

Morbid Obesity Centre, Department of Medicine, Vestfold Hospital Trust, Tønsberg, Norway.

Anatomical changes in the gastrointestinal tract and subsequent weight loss may influence drug disposition and thus drug dosing following bariatric surgery. This review systematically examines the effects of bariatric surgery on drug pharmacokinetics, focusing especially on the mechanisms involved in restricting oral bioavailability. Studies with a longitudinal before-after design investigating the pharmacokinetics of at least one drug were reviewed. The need for dose adjustment following bariatric surgery was examined, as well as the potential for extrapolation to other drugs subjected to coinciding pharmacokinetic mechanisms. A total of 22 original articles and 32 different drugs were assessed. The majority of available data is based on Roux-en-Y gastric bypass (RYGBP) (18 of 22 studies), and hence, the overall interpretation is more or less limited to RYGBP. In the case of the majority of studied drugs, an increased absorption rate was observed early after RYGBP. The effect on systemic exposure allows for a low degree of extrapolation, including between drugs subjected to the same major metabolic and transporter pathways. On the basis of current understanding, predicting the pharmacokinetic change for a specific drug following RYGBP is challenging. Close monitoring of each individual drug is therefore recommended in the early postsurgical phase. Future studies should focus on the long-term effects of bariatric surgery on drug disposition, and they should also aim to disentangle the effects of the surgery itself and the subsequent weight loss.
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http://dx.doi.org/10.1111/obr.12869DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6852510PMC
September 2019

Impact of body weight, low energy diet and gastric bypass on drug bioavailability, cardiovascular risk factors and metabolic biomarkers: protocol for an open, non-randomised, three-armed single centre study (COCKTAIL).

BMJ Open 2018 05 29;8(5):e021878. Epub 2018 May 29.

Cardiovascular, Renal and Metabolism Translational Medicine Unit, Early Clinical Development, IMED Biotech Unit, AstraZeneca Gothenburg, Gothenburg, Sweden.

Introduction: Roux-en-Y gastric bypass (GBP) is associated with changes in cardiometabolic risk factors and bioavailability of drugs, but whether these changes are induced by calorie restriction, the weight loss or surgery per se, remains uncertain. The COCKTAIL study was designed to disentangle the short-term (6 weeks) metabolic and pharmacokinetic effects of GBP and a very low energy diet (VLED) by inducing a similar weight loss in the two groups.

Methods And Analysis: This open, non-randomised, three-armed, single-centre study is performed at a tertiary care centre in Norway. It aims to compare the short-term (6 weeks) and long-term (2 years) effects of GBP and VLED on, first, bioavailability and pharmacokinetics (24 hours) of probe drugs and biomarkers and, second, their effects on metabolism, cardiometabolic risk factors and biomarkers. The primary outcomes will be measured as changes in: (1) all six probe drugs by absolute bioavailability area under the curve (AUC/AUC) of midazolam (CYP3A4 probe), systemic exposure (AUC) of digoxin and rosuvastatin and drug:metabolite ratios for omeprazole, losartan and caffeine, levels of endogenous CYP3A biomarkers and genotypic variation, changes in the expression and activity data of the drug-metabolising, drug transport and drug regulatory proteins in biopsies from various organs and (2) body composition, cardiometabolic risk factors and metabolic biomarkers.

Ethics And Dissemination: The COCKTAIL protocol was reviewed and approved by the Regional Committee for Medical and Health Research Ethics (Ref: 2013/2379/REK sørøst A). The results will be disseminated to academic and health professional audiences and the public via presentations at conferences, publications in peer-reviewed journals and press releases and provided to all participants.

Trial Registration Number: NCT02386917.
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http://dx.doi.org/10.1136/bmjopen-2018-021878DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5988193PMC
May 2018

Determination of Tacrolimus Concentration and Protein Expression of P-Glycoprotein in Single Human Renal Core Biopsies.

Ther Drug Monit 2018 06;40(3):292-300

Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo.

Background: Tacrolimus (TAC) is currently the cornerstone of immunosuppressive protocols for renal transplant recipients. Despite therapeutic whole blood monitoring, TAC is associated with nephrotoxicity, and it has been hypothesized that intrarenal accumulation of TAC and/or its metabolites are involved. As TAC is a substrate of P-glycoprotein (P-gp), the expression and activity of this efflux transporter could influence the levels of TAC in renal tissue. The primary aim of this study was to develop and validate a method for quantification of TAC in tissue homogenates from single human renal core biopsies. The secondary aim was to provide measures of P-gp expression and of the demethylated metabolites of TAC in the same renal biopsy.

Methods: Human renal tissue, with and without clinical TAC exposure, was used for method development and validation. Homogenates were prepared with bead-beating, and concentrations of TAC and its demethylated metabolites were analyzed with liquid chromatography tandem mass spectrometry after protein precipitation. A Western blot method was used for semiquantification of P-gp expression in the homogenates. The final methods were applied to renal core biopsies from 2 transplant patients.

Results: The TAC assay showed within- and between-run mean accuracy between 99.7% and 107% and coefficients of variation ≤6.7%. Matrix effects were nonsignificant, and samples were stable for 3 months preanalytically when stored at -80°C. TAC concentrations in the renal core biopsies were 62.6 and 43.7 pg/mg tissue. The methods for measurement of desmethyl-TAC and P-gp expression were suitable for semiquantification in homogenates from renal core biopsies.

Conclusions: These methods may be valuable for the elucidation of the pharmacokinetic mechanisms behind TAC-induced nephrotoxicity in renal transplant recipients.
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http://dx.doi.org/10.1097/FTD.0000000000000510DOI Listing
June 2018
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