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- Fredin, Maria Fritsch, 1970, et al.
(författare)
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The application and relevance of ex vivo culture systems for assessment of IBD treatment in murine models of colitis
- 2008
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Ingår i: Pharmacological Research. - : Elsevier BV. - 1043-6618 .- 1096-1186. ; 58:3-4, s. 222-231
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate the relevance of mouse ex vivo cultures as a first screening model for new therapeutic agents of Inflammatory Bowel Disease (IBD). Two murine models (dextran sodium sulphate (DSS)-induced colitis and Gαi2-deficient mice) and two anti-inflammatory agents (methyl-prednisolone and the proteasome inhibitor MG132) were evaluated. The in vivo effects of methyl-prednisolone were assessed in both models. Ex vivo colonic tissue from both mouse models were cultured in the presence or absence of the drugs and TaqMan Low-Density arrays were used to assess the regulation of inflammatory genes before and after drug treatment. Colitis induced a similar inflammatory gene profile in both mouse models in in vivo studies and in ex vivo cultures. The differences encountered reflected the different phases of colitis in the models, e.g. innate cytokine/chemokine profile in the DSS model and T cell related markers in Gαi2-deficient mice. After steroid treatment, a similar pattern of genes was suppressed in the two mouse models. We confirmed the suppression of inflammatory gene expression for IL-1β, IL-6 and iNOS in ex vivo and in vivo colons from both mouse models by quantitative RT-PCR. Importantly, the inflammatory responses in the murine ex vivo culture system reflected the in vivo response in the inflamed colonic tissue as assessed by changes in inflammatory gene expression, suggesting that the murine culture system can be used for validation of future IBD therapies.
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| 3. |
- Teerlink, Tom, et al.
(författare)
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Cellular ADMA : regulation and action.
- 2009
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Ingår i: Pharmacological Research. - : Elsevier BV. - 1043-6618 .- 1096-1186. ; 60:6, s. 448-460
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Forskningsöversikt (refereegranskat)abstract
- Asymmetric (N(G),N(G)) dimethylarginine (ADMA) is present in plasma and cells. It can inhibit nitric oxide synthase (NOS) that generates nitric oxide (NO) and cationic amino acid transporters (CATs) that supply intracellular NOS with its substrate, l-arginine, from the plasma. Therefore, ADMA and its transport mechanisms are strategically placed to regulate endothelial function. This could have considerable clinical impact since endothelial dysfunction has been detected at the origin of hypertension and chronic kidney disease (CKD) in human subjects and may be a harbinger of large vessel disease and cardiovascular disease (CVD). Indeed, plasma levels of ADMA are increased in many studies of patients at risk for, or with overt CKD or CVD. However, the levels of ADMA measured in plasma of about 0.5micromol.l(-1) may be below those required to inhibit NOS whose substrate, l-arginine, is present in concentrations many fold above the Km for NOS. However, NOS activity may be partially inhibited by cellular ADMA. Therefore, the cellular production of ADMA by protein arginine methyltransferase (PRMT) and protein hydrolysis, its degradation by N(G),N(G)-dimethylarginine dimethylaminohydrolase (DDAH) and its transmembrane transport by CAT that determines intracellular levels of ADMA may also determine the state of activation of NOS. This is the focus of the review. It is concluded that cellular levels of ADMA can be 5- to 20-fold above those in plasma and in a range that could tonically inhibit NOS. The relative importance of PRMT, DDAH and CAT for determining the intracellular NOS substrate:inhibitor ratio (l-arginine:ADMA) may vary according to the pathophysiologic circumstance. An understanding of this important balance requires knowledge of these three processes that regulate the intracellular levels of ADMA and arginine.
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