| 1. |
- Lundquist, Patrik, et al.
(författare)
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The Impact of Solute Carrier (SLC) Drug Uptake Transporter Loss in Human and Rat Cryopreserved Hepatocytes on Clearance Predictions
- 2014
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Ingår i: Drug Metabolism And Disposition. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 0090-9556 .- 1521-009X. ; 42:3, s. 469-480
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Tidskriftsartikel (refereegranskat)abstract
- Cryopreserved hepatocytes are often used as a convenient tool in studies of hepatic drug metabolism and disposition. In this study, the expression and activity of drug transporters in human and rat fresh and cryopreserved hepatocytes was investigated. In human cryopreserved hepatocytes, Western blot analysis indicated that protein expression of the drug uptake transporters [human Na+-taurocholate cotransporting polypeptide (NTCP), human organic anion transporting polypeptides (OATPs), human organic anion transporters, and human organic cation transporters (OCTs)] was considerably reduced compared with liver tissue. In rat cryopreserved cells, the same trend was observed but to a lesser extent. Several rat transporters were reduced as a result of both isolation and cryopreservation procedures. Immunofluorescence showed that a large portion of remaining human OATP1B1 and OATP1B3 transporters were internalized in human cryopreserved hepatocytes. Measuring uptake activity using known substrates of OATPs, OCTs, and NTCP showed decreased activity in cryopreserved as compared with fresh hepatocytes in both species. The reduced uptake in cryopreserved hepatocytes limited the in vitro metabolism of several AstraZeneca compounds. A retrospective analysis of clearance predictions of AstraZeneca compounds suggested systematic lower clearance predicted using metabolic stability data from human cryopreserved hepatocytes compared with human liver microsomes. This observation is consistent with a loss of drug uptake transporters in cryopreserved hepatocytes. In contrast, the predicted metabolic clearance from fresh rat hepatocytes was consistently higher than those predicted from liver microsomes, consistent with retention of uptake transporters. The uptake transporters, which are decreased in cryopreserved hepatocytes, may be rate-limiting for the metabolism of the compounds and thus be one explanation for underpredictions of in vivo metabolic clearance from cryopreserved hepatocytes.
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| 2. |
- Bergh Thorén, Fredrik, 1976, et al.
(författare)
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Human NK Cells induce neutrophil apoptosis via an NKp46- and Fas-dependent mechanism.
- 2012
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Ingår i: Journal of immunology (Baltimore, Md. : 1950). - : The American Association of Immunologists. - 1550-6606 .- 0022-1767. ; 188:4, s. 1668-74
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Tidskriftsartikel (refereegranskat)abstract
- Polymorphonuclear neutrophils (PMN) are potent inflammatory effector cells essential to host defense, but at the same time they may cause significant tissue damage. Thus, timely induction of neutrophil apoptosis is crucial to avoid tissue damage and induce resolution of inflammation. NK cells have been reported to influence innate and adaptive immune responses by multiple mechanisms including cytotoxicity against other immune cells. In this study, we analyzed the effect of the interaction between NK cells and neutrophils. Coculture experiments revealed that human NK cells could trigger caspase-dependent neutrophil apoptosis in vitro. This event was dependent on cell-cell contact, and experiments using blocking Abs indicated that the effect was mediated by the activating NK cell receptor NKp46 and the Fas pathway. CD56-depleted lymphocytes had minimal effects on neutrophil survival, suggesting that the ability to induce neutrophil apoptosis is specific to NK cells. Our findings provide evidence that NK cells may accelerate neutrophil apoptosis, and that this interaction may be involved in the resolution of acute inflammation.
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| 4. |
- Björkman, Lena, 1965, et al.
(författare)
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The proinflammatory activity of recombinant serum amyloid A is not shared by the endogenous protein in the circulation.
- 2010
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Ingår i: Arthritis and rheumatism. - : Wiley. - 1529-0131 .- 0004-3591. ; 62:6, s. 1660-5
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Elevated serum levels of the acute-phase protein serum amyloid A (SAA) are a marker for active rheumatoid arthritis (RA), and SAA can also be found in the tissues of patients with active RA. Based on a number of studies with recombinant SAA (rSAA), the protein has been suggested to be a potent proinflammatory mediator that activates human neutrophils, but whether endogenous SAA shares these proinflammatory activities has not been directly addressed. The present study was undertaken to investigate whether SAA in the plasma of patients with RA possesses proinflammatory properties and activates neutrophils in a manner similar to that of the recombinant protein. METHODS: Neutrophil activation was monitored by flow cytometry, based on L-selectin shedding from cell surfaces. Whole blood samples from healthy subjects and from RA patients with highly elevated SAA levels were studied before and after stimulation with rSAA as well as purified endogenous SAA. RESULTS: Recombinant SAA potently induced cleavage of L-selectin from neutrophils and in whole blood samples. Despite highly elevated SAA levels, L-selectin was not down-regulated on RA patient neutrophils as compared with neutrophils from healthy controls. Spiking SAA-rich whole blood samples from RA patients with rSAA, however, resulted in L-selectin shedding. In addition, SAA purified from human plasma was completely devoid of neutrophil- or macrophage-activating capacity. CONCLUSION: The present findings show that rSAA is proinflammatory but that this activity is not shared by endogenous SAA, either when present in the circulation of RA patients or when purified from plasma during an acute-phase response.
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| 5. |
- Björnsdottir, Halla, et al.
(författare)
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Inhibition of phospholipase A(2) abrogates intracellular processing of NADPH-oxidase derived reactive oxygen species in human neutrophils.
- 2013
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Ingår i: Experimental cell research. - : Elsevier BV. - 1090-2422 .- 0014-4827. ; 319:5, s. 761-774
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Tidskriftsartikel (refereegranskat)abstract
- Upon activation of human neutrophils, superoxide can be produced at two cellular sites; either in the plasma membrane, giving extracellular release of oxidants, or in intracellular organelles, resulting in oxidants being retained in the cell. The involvement of phospholipase A(2) (PLA(2)) in phorbol myristate acetate (PMA)-induced activation of the two pools of NADPH-oxidase was investigated using a variety of PLA(2) inhibitors and the oxidase activity was measured by luminol/isoluminol-amplified chemiluminescence (CL). Two of the seven inhibitors were without effect, two inhibitors inhibited both intra- and extracellular ROS production equally, and three inhibitors inhibited intracellular but not extracellular CL. Using another technique to measure ROS, PHPA oxidation, we found that intracellular ROS production was unaltered with the three last inhibitors, indicating that PLA(2) is not involved in the NADPH-oxidase activity per se, but in the intracellular processing of the radicals necessary for the CL reaction to take place. The PLA(2) inhibitors did not abolish the activity of myeloperoxidase (MPO), an enzyme necessary for intracellular CL to occur. Instead, we suggest that these PLA(2) inhibitors block heterotypic granule fusion and prohibit the colocalization of ROS and MPO needed for intracellular CL activity.
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| 6. |
- Brown, Kelly, 1973, et al.
(författare)
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Host defense peptide LL-37 selectively reduces proinflammatory macrophage responses.
- 2011
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Ingår i: Journal of immunology (Baltimore, Md. : 1950). - : The American Association of Immunologists. - 1550-6606 .- 0022-1767. ; 186:9, s. 5497-505
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Tidskriftsartikel (refereegranskat)abstract
- The human cathelicidin peptide, LL-37, is a host defense peptide with a wide range of immunomodulatory activities and modest direct antimicrobial properties. LL-37 can exert both pro- and anti-inflammatory effects and can modulate the proinflammatory responses of human peripheral blood monocytes and epithelial cells. In this study, we evaluated the effect of LL-37 on mouse bone marrow-derived macrophages (BMDM) and tissue macrophages in vitro and in vivo. LL-37 dramatically reduced TNF-α and NO levels produced by LPS and IFN-γ-polarized M1-BMDM and slightly reduced reactive oxygen species production by these cells. LL-37 did not affect the ability of IL-4-polarized M2-BMDM to upregulate arginase activity, although it did inhibit LPS-induced TNF-α secretion in these cells. LL-37 did not compromise the ability of M1-polarized BMDM to phagocytose and kill bacteria and did not affect the uptake of apoptotic neutrophils by M2-polarized BMDM. However, LL-37-treated M1-BMDM were more efficient at suppressing tumor growth in vitro. LL-37 significantly reduced LPS-induced TNF-α secretion in ex vivo alveolar macrophages, whereas its effect on peritoneal macrophages was much less dramatic. Effective inhibition of LPS-induced TNF-α secretion by alveolar macrophages also occurred in vivo when LL-37 was administered by intratracheal injection. This demonstrates a selective ability of LL-37 to decrease M1-BMDM, M2-BMDM, and tissue macrophage production of the proinflammatory cytokine TNF-α in response to LPS while leaving other crucial anti-inflammatory M1 and M2 macrophage functions unaltered.
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| 7. |
- Bueters, Tjerk, et al.
(författare)
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Rat poorly predicts the combined non-absorbed and presystemically metabolized fractions in the human
- 2013
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Ingår i: Xenobiotica. - : Informa UK Limited. - 0049-8254 .- 1366-5928. ; 43:7, s. 607-616
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Tidskriftsartikel (refereegranskat)abstract
- 1. Intestinal loss, 1 - (F(obs)/f(H)), is the missing fraction of the dose that is unexplained by systemic clearance. Here, we investigated whether intestinal loss in rat is predictive for human, and whether intestinal metabolism explained observed differences between rat and human.2. For 81 marketed drugs, human and rat intestinal loss values were calculated from the literature and in-house sources. To examine the contribution of intestinal cytochrome P450-mediated metabolism to the high observed intestinal loss in the rat, metabolism was determined in rat and human intestinal microsomes for 15 compounds.3. Oral bioavailability poorly correlated between rat and human. Twenty-two compounds in the human and 47 compounds in the rat showed an intestinal loss of more than 20%. The intestinal availability for many compounds was higher in human than in rat. Selected compounds, however, were more stable in rat than in human intestinal microsomes.4. The rat poorly predicts the risk for intestinal loss in human; many compounds in rat had lower bioavailability than anticipated based on the hepatic clearance, but demonstrated little intestinal loss in human. This discrepancy appeared not to be caused by a higher cytochrome P450-mediated intestinal metabolism in the rat.
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| 10. |
- Bylund-Grenklo, Tove, et al.
(författare)
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Self-injury in youths who lost a parent to cancer : nationwide study of the impact of family-related and health-care-related factors
- 2014
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Ingår i: Psycho-Oncology. - : Wiley. - 1057-9249 .- 1099-1611. ; 23:9, s. 989-997
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Self-injury, a manifestation of severe psychological distress, is increased in cancer-bereaved youths. Little is known about the potential influence on the risk for self-injury of factors that could be clinically relevant to and modifiable by the health-care professionals involved in the care of the dying parent.METHODS: In a nationwide population-based anonymous study, 622 (73.1%) youths (aged 18-26) who, 6 to 9 years earlier at ages 13 to 16, had lost a parent to cancer answered study-specific questions about self-injury and factors related to the family and parental health care.RESULTS: Univariable analyses showed that the risk for self-injury was increased among cancer-bereaved youths who reported poor family cohesion the years before (relative risk [RR], 3.4, 95% confidence interval [CI], 2.5-4.6) and after the loss (RR, 3.3, 95% CI, 2.4-4.4), distrust in the health care provided to the dying parent (RR, 1.7, 95% CI, 1.2-2.4), perceiving poor health-care efforts to cure the parent (RR 1.5, 95% CI, 1.1-2.1) and poor efforts to prevent suffering (RR, 1.6, 95% CI, 1.1-2.4), that at least one of their parents had been depressed or had troubles in life (RR, 1.5, CI, 1.1-2.1) and believing 3 days before the loss that the treatment would probably cure the parent (RR, 1.6, CI, 1.1-2.3). In the total multivariable models, only poor family cohesion before and after the loss remained statistically significantly associated with self-injury.CONCLUSION: Poor family cohesion before and after the loss of a parent to cancer is associated with an increased risk of self-injury in teenage children. Copyright © 2014 John Wiley & Sons, Ltd.
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