| 1. |
- Crawshaw, Marilyn, et al.
(författare)
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Disclosure and donor-conceived children
- 2017
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Ingår i: Human Reproduction. - : Oxford University Press. - 0268-1161 .- 1460-2350. ; 32:7, s. 1535-1536
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Darwich, Adam S., et al.
(författare)
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IMI - Oral biopharmaceutics tools project - Evaluation of bottom-up PBPK prediction success part 3 : Identifying gaps in system parameters by analysing In Silico performance across different compound classes
- 2017
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Ingår i: European Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0928-0987 .- 1879-0720. ; 96, s. 626-642
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Tidskriftsartikel (refereegranskat)abstract
- Three Physiologically Based Pharmacokinetic software packages (GI-Sim, Simcyp (R) Simulator, and GastroPlus (TM)) were evaluated as part of the Innovative Medicine Initiative Oral Biopharmaceutics Tools project (OrBiTo) during a blinded "bottom-up" anticipation of human pharmacokinetics. After data analysis of the predicted vs. measured pharmacokinetics parameters, it was found that oral bioavailability (F-oral) was underpredicted for compounds with low permeability, suggesting improper estimates of intestinal surface area, colonic absorption and/or lack of intestinal transporter information. Foralwas also underpredicted for acidic compounds, suggesting overestimation of impact of ionisation on permeation, lack of information on intestinal transporters, or underestimation of solubilisation of weak acids due to less than optimal intestinal model pH settings or underestimation of bile micelle contribution. F-oral was overpredicted for weak bases, suggesting inadequate models for precipitation or lack of in vitro precipitation information to build informed models. Relative bioavailability was underpredicted for both high logP compounds as well as poorly water-soluble compounds, suggesting inadequate models for solubility/dissolution, underperforming bile enhancement models and/or lack of biorelevant solubility measurements. These results indicate areas for improvement in model software, modelling approaches, and generation of applicable input data. However, caution is required when interpreting the impact of drug-specific properties in this exercise, as the availability of input parameters was heterogeneous and highly variable, and the modellers generally used the data "as is" in this blinded bottom-up prediction approach.
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| 3. |
- Eriksson, Johanna, et al.
(författare)
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Pulmonary Dissolution of Poorly Soluble Compounds Studied in an ex Vivo Rat Lung Model
- 2019
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Ingår i: Molecular Pharmaceutics. - : American Chemical Society (ACS). - 1543-8384 .- 1543-8392. ; 16:7, s. 3053-3064
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Tidskriftsartikel (refereegranskat)abstract
- Many inhaled drugs are poorly water soluble, and the dissolution rate is often the rate-limiting step in the overall absorption process. To improve understanding of pulmonary drug dissolution, four poorly soluble inhalation compounds (AZD5423 (a developmental nonsteroidal glucocorticoid), budesonide, fluticasone furoate (FF), and fluticasone propionate (FP)) were administered as suspensions or dry powders to the well-established isolated perfused 4 rat lung (IPL) model. Two particle size distributions (d50 = 1.2 mu m and d50 = 2.8 mu m) were investigated for AZD5423. The pulmonary absorption rates of the drugs from the suspensions and dry powders were compared with historical absorption data for solutions to improve understanding of the effects of dissolution on the overall pulmonary absorption process for poorly soluble inhaled drugs. A physiologically based biopharmaceutical in silico model was used to analyze the experimental IPL data and to estimate a dissolution parameter (K-ex vivo). A similar in silico approach was applied to in vitro dissolution data from the literature to obtain an in vitro dissolution parameter (Kin vitro). When FF, FP, and the larger particles of AZD5423 were administered as suspensions, drug dissolution was the rate-limiting step in the overall absorption process. However, this was not the case for budesonide, which has the highest aqueous solubility (61 mu M), and the smaller particles of AZD5423, probably because of the increased surface area available for dissolution (d50 = 1.2 mu m). The estimated dissolution parameters were ranked in accordance with the solubility of the drugs, and there was good agreement between k(ex vivo) and k(in vitro). The dry powders of all the compounds were absorbed more slowly than the suspensions, indicating that wetting is an important parameter for the dissolution of dry powders. A wetting factor was introduced to the in silico model to explain the difference in absorption profiles between the suspensions and dry powders where AZD5423 had the poorest wettability followed by FP and FF. The IPL model in combination with an in silico model is a useful tool for investigating pulmonary dissolution and improving understanding of dissolution-related parameters for poorly soluble inhaled compounds.
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| 4. |
- Eriksson, Johanna, et al.
(författare)
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Pulmonary drug absorption and systemic exposure in human : Predictions using physiologically based biopharmaceutics modeling
- 2020
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Ingår i: European journal of pharmaceutics and biopharmaceutics. - : ELSEVIER. - 0939-6411 .- 1873-3441. ; 156, s. 191-202
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Tidskriftsartikel (refereegranskat)abstract
- Systemic exposure of inhaled drugs is used to estimate the local lung exposure and assess systemic side effects for drugs with local pharmacological targets. Predicting systemic exposure is therefore central for successful development of drugs intended to be inhaled. Currently, these predictions are based mainly on data from in vitro experiments, but the accuracy of these predictions might be improved if they were based on data with higher physiological relevance. In this study, systemic exposure was simulated by applying biopharmaceutics input parameters from isolated perfused rat lung (IPL) data to a lung model developed in MoBi (R) as an extension to the full physiologically-based pharmacokinetic (PBPK) model in PK-Sim (R). These simulations were performed for a set of APIs with a variety of physicochemical properties and formulation types. Simulations based on rat IPL data were also compared to simulations based on in vitro data. The predictive performances of the simulations were evaluated by comparing simulated plasma concentration-time profiles to clinical observations after pulmonary administration. Simulations using IPL-based input parameters predicted systemic exposure well, with predicted AUCs within two-fold of the observed value for nine out of ten drug compounds/formulations, and predicted Cmax values within two-fold for eight out of ten drug compounds/formulations. Simulations using input parameters based on IPL data performed generally better than simulations based on in vitro input parameters. These results suggest that the developed model in combination with IPL data can be used to predict human lung absorption for compounds with different physicochemical properties and types of inhalation formulations.
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| 5. |
- Gustavsson, Johanna, 1956-, et al.
(författare)
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Localization of the insulin receptor in caveolae of adipocyte plasma membrane
- 1999
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Ingår i: The FASEB Journal. - 0892-6638 .- 1530-6860. ; 13:14, s. 1961-1971
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Tidskriftsartikel (refereegranskat)abstract
- The insulin receptor is a transmembrane protein of the plasma membrane, where it recognizes extracellular insulin and transmits signals into the cellular signaling network. We report that insulin receptors are localized and signal in caveolae microdomains of adipocyte plasma membrane. Immunogold electron microscopy and immunofluorescence microscopy show that insulin receptors are restricted to caveolae and are colocalized with caveolin over the plasma membrane. Insulin receptor was enriched in a caveolae-enriched fraction of plasma membrane. By extraction with β-cyclodextrin or destruction with cholesterol oxidase, cholesterol reduction attenuated insulin receptor signaling to protein phosphorylation or glucose transport. Insulin signaling was regained by spontaneous recovery or by exogenous replenishment of cholesterol. β-Cyclodextrin treatment caused a nearly complete annihilation of caveolae invaginations as examined by electron microscopy. This suggests that the receptor is dependent on the caveolae environment for signaling. Insulin stimulation of cells prior to isolation of caveolae or insulin stimulation of the isolated caveolae fraction increased tyrosine phosphorylation of the insulin receptor in caveolae, demonstrating that insulin receptors in caveolae are functional. Our results indicate that insulin receptors are localized to caveolae in the plasma membrane of adipocytes, are signaling in caveolae, and are dependent on caveolae for signaling.
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| 6. |
- Karlsson, Margareta, 1942-, et al.
(författare)
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Colocalization of insulin receptor and insulin receptor substrate-1 to caveolae in primary human adipocytes
- 2004
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Ingår i: European Journal of Biochemistry. - : Wiley. - 0014-2956 .- 1432-1033. ; 271:12, s. 2471-2479
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Tidskriftsartikel (refereegranskat)abstract
- Caveolae are plasma membrane invaginations with several functions, one of which appears to be to organize receptor mediated signalling. Here we report that in primary human subcutaneous adipocytes the insulin receptor was localized to caveolae by electron microscopy/immunogold detection and by isolating caveolae from plasma membranes. Part of insulin receptor substrate 1 (IRS1), the immediate downstream signal mediator, was colocalized with the insulin receptor in the plasma membrane and caveolae, as demonstrated by immunofluorescence microscopy, immunogold electron microscopy, and immunogold electron microscopy of transfected recombinant HA-IRS1. In contrast, rat epididymal adipocytes lacked IRS1 at the plasma membrane. Depletion of cholesterol from the cells using β-cyclodextrin blocked insulin stimulation of glucose uptake, insulin inhibition of perilipin phosphorylation in response to isoproterenol, and insulin stimulation of protein kinase B and Map-kinases extracellular signal-related kinase (ERK)1/2 phosphorylation. Insulin-stimulated phosphorylation of the insulin receptor and IRS1 was not affected, indicating that caveolae integrity is required downstream of IRS1. In conclusion we show that insulin receptor and IRS1 are both caveolar proteins and that caveolae are required for both metabolic and mitogenic control in human adipocytes. Our results establish caveolae as foci of insulin action and stress the importance of examining human cells in addition to animal cells and cell lines.
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| 7. |
- Karlsson, Margareta, et al.
(författare)
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In human adipocytes the insulin receptor and IRS1 are localized in caveolae, and caveolae destruction makes cells resistant to insulin signaling for metabolic and mitogenic control
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Caveolae are plasma membrane invaginations with several functions, one of which appears to be to organize receptor mediated sigoaling. Here we show that in human adipocytes the iosulin receptor is localized in caveolae: by electron microscopy and immunogold detection and by isolating caveolae from plasma membranes. We similarly demonstrate that significant part of the immediate downstream signal mediator IRS1 is localized at the plasma membrane and caveolae. A detailed image shows the caveola as a bulb, protroding into the cell interior, with a neck attaching it to the plasma membrane. The caveolar structural protein caveolin is localized in the neck aod not in the bulb of the caveola. The receptor is active in caveolae since insulin stimulation caused tyrosine specific phosphorylation of the receptor recovered in isolated caveolae. Caveolae contain a major part of the free cholesterol in the plasma membrane and cholesterol is a stroctural component of caveolae. Depletion of cholesterol from the cells using B-cyclodextrio blocks insulin stimulation of glucose uptake, insulin inhibition of perilipin phosphorylation in response to isoproterenol, and insulio stimulation of protein kinase B and Map-kinases ERK1/2 phosphorylation- in effect making the human adipocytes insulin resistant. The insulin-stimulated phosphorylation of the insulin receptor and IRS1 are, however, not affected, indicating that caveolae integrity is required downstream of IRS1, consistent with its colocalization with the insulin receptor io caveolae in human adipocytes.
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| 8. |
- Karlsson, Margareta, 1942-, et al.
(författare)
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Insulin induces translocation of glucose transporter GLUT4 to plasma membrane caveolae in adipocytes
- 2002
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Ingår i: The FASEB Journal. - : Wiley. - 0892-6638 .- 1530-6860. ; 16:2, s. 249-251
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Tidskriftsartikel (refereegranskat)abstract
- Insulin-stimulated glucose uptake in muscle and adipose tissue is the result of translocation of insulin-regulated glucose transporters (GLUT4) from intracellular vesicles to the plasma membrane. Here we report that GLUT4 in the plasma membrane of 3T3-L1 adipocytes were located predominantly in caveolae invaginations: by immunogold electron microscopy of plasma membranes, 88% of GLUT4 were localized to caveolae structures and this distribution within the plasma membrane was not affected by insulin. By immunofluorescence microscopy, a major part of GLUT 4 was colocalized with caveolin. The total amount of GLUT4 in the plasma membrane increased 2.2-fold in response to insulin as determined by immunogold electron or immunofluorescence microscopy. GLUT4 were enriched in caveolae fractions isolated without detergents from plasma membranes of rat adipocytes. In these fractions, GLUT4 were largely confined to caveolin-containing membranes of the caveolae preparation isolated from insulin-stimulated cells, determined by electron microscopy. Insulin increased the amount of GLUT4 2.7-fold in this caveolae fraction. Caveolae were purified further by immunoisolation with antibodies against caveolin. The amount of GLUT4 increased to the same extent in the immunopurified caveolae as in the cruder caveolae fractions from insulin-stimulated cells. We conclude that insulin induces translocation of GLUT4 to caveolae.
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| 9. |
- Margolskee, Alison, et al.
(författare)
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IMI - Oral biopharmaceutics tools project - Evaluation of bottom-up PBPK prediction success part 2 : An introduction to the simulation exercise and overview of results
- 2017
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Ingår i: European Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0928-0987 .- 1879-0720. ; 96, s. 610-625
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Tidskriftsartikel (refereegranskat)abstract
- Orally administered drugs are subject to a number of barriers impacting bioavailability (F-oral), causing challenges during drug and formulation development. Physiologically-based pharmacokinetic (PBPK) modelling can help during drug and formulation development by providing quantitative predictions through a systems approach. The performance of three available PBPK software packages (GI-Sim, Simcyp (R), and GastroPlus (TM)) were evaluated by comparing simulated and observed pharmacokinetic (PK) parameters. Since the availability of input parameters was heterogeneous and highly variable, caution is required when interpreting the results of this exercise. Additionally, this prospective simulation exercise may not be representative of prospective modelling in industry, as API information was limited to sparse details. 43 active pharmaceutical ingredients (APIs) from the OrBiTo database were selected for the exercise. Over 4000 simulation output files were generated, representing over 2550 study arm-institution-software combinations and approximately 600 human clinical study arms simulated with overlap. 84% of the simulated study arms represented administration of immediate release formulations, 11% prolonged or delayed release, and 5% intravenous (i.v.). Higher percentages of i.v. predicted area under the curve (AUC) were within two-fold of observed (52.9%) compared to per oral (p.o.) (37.2%), however, F-oral and relative AUC (F-rel) between p.o. formulations and solutions were generally well predicted (64.7% and 75.0%). Predictive performance declined progressing from i.v. to solution and immediate release tablet, indicating the compounding error with each layer of complexity. Overall performance was comparable to previous large-scale evaluations. A general overprediction of AUC was observed with average fold error (AFE) of 1.56 over all simulations. AFE ranged from 0.0361 to 64.0 across the 43 APIs, with 25 showing overpredictions. Discrepancies between software packages were observed for a few APIs, the largest being 606, 171, and 81.7-fold differences in AFE between SimCYP and GI-Sim, however average performance was relatively consistent across the three software platforms.
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| 10. |
- Parpal, Santiago, et al.
(författare)
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Cholesterol Depletion Disrupts Caveolae and Insulin Receptor Signaling for Metabolic Control via Insulin Receptor Substrate-1, but Not for Mitogen-activated Protein Kinase Control
- 2001
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 276:13, s. 9670-9678
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Tidskriftsartikel (refereegranskat)abstract
- Insulin exerts its cellular control through receptor binding in caveolae in plasmalemma of target cells (Gustavsson, J., Parpal, S., Karlsson, M., Ramsing, C., Thorn, H., Borg, M., Lindroth, M., Peterson, K. H., Magnusson, K.-E., and Strålfors, P. (1999) FASEB. J. 13, 1961–1971). We now report that a progressive cholesterol depletion of 3T3-L1 adipocytes with β-cyclodextrin gradually destroyed caveolae structures and concomitantly attenuated insulin stimulation of glucose transport, in effect making cells insulin-resistant. Insulin access to or affinity for the insulin receptor on rat adipocytes was not affected as determined by 125I-insulin binding. By immunoblotting of plasma membranes, total amount of insulin receptor and of caveolin remained unchanged. Receptor autophosphorylation in response to insulin was not affected by cholesterol depletion. Insulin treatment of isolated caveolae preparations increased autophosphorylation of receptor before and following cholesterol depletion. Insulin-increased tyrosine phosphorylation of an immediate downstream signal transducer, insulin receptor substrate-1, and activation of the further downstream protein kinase B were inhibited. In contrast, insulin signaling to mitogenic control as determined by control of the extracellular signal-related kinases 1/2, mitogen-activated protein kinase pathway was not affected. Insulin did not control Shc phosphorylation, and Shc did not control extracellular signal-related kinases 1/2, whereas cholesterol depletion constitutively phosphorylated Shc. In conclusion, caveolae are critical for propagating the insulin receptor signal to downstream targets and have the potential for sorting signal transduction for metabolic and mitogenic effects.
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