Biomedical subjects

Björn Mellgård

Publications and source records attributed to Björn Mellgård.

3 recordsLinked to original sources

PubMed2005

Anti-inflammatory effects of budesonide in intestinal epithelial cells.

The glucocorticosteroid budesonide is one of the mainstay treatments in inflammatory bowel disease. The aim of this study was to investigate its effects on Caco-2 cells upon coculture with LPS stimulated macrophages, or with conditioned medium (CM) from the same. The mRNA expression of the chemokines IL-8 and ENA-78 were upregulated in Caco-2 cells, which was always more pronounced in the coculture, as compared to the CM situation, with the ENA-78 induction being higher than of IL-8. Addition of budesonide to the apical side of Caco-2 cells, decreased both IL-8 and ENA-78 mRNA levels in a dose dependent manner. A reduction in trans epithelial electrical resistance (TEER) and an increase in the apical-basolateral transport of fluoresceinated sulfonic acid (FS) were observed in the Caco-2 cells both in cocultures and CM experiments. The reduction in TEER was counteracted by budesonide, whereas it had no effect on the FS transport. We conclude that budesonide exert an anti-inflammatory effect directly on intestinal epithelial cells, which may contribute to the overall action of budesonide in the treatment of inflammatory bowel diseases.

Anti-Inflammatory Agents↗

PubMed2004

A comparison of oligonucleotide and cDNA-based microarray systems.

Large-scale public data mining will become more common as public release of microarray data sets becomes a corequisite for publication. Therefore, there is an urgent need to clarify whether data from different microarray platforms are comparable. To assess the compatibility of microarray data, results were compared from the two main types of high-throughput microarray expression technologies, namely, an oligonucleotide-based and a cDNA-based platform, using RNA obtained from complex tissue (human colonic mucosa) of five individuals. From 715 sequence-verified genes represented on both platforms, 64% of the genes matched in "present" or "absent" calls made by both platforms. Calls were influenced by spurious signals caused by Alu repeats in cDNA clones, clone annotation errors, or matched probes that were designed to different regions of the gene; however, these factors could not completely account for the level of call discordance observed. Expression levels in sequence-verified, platform-overlapping genes were not related, as demonstrated by weakly positive rank order correlation. This study demonstrates that there is only moderate overlap in the results from the two array systems. This fact should be carefully considered when performing large-scale analyses on data originating from different microarray platforms.

Aged↗

PubMed2003

Design and synthesis of dihydrofolate reductase inhibitors encompassing a bridging ester group. Evaluation in a mouse colitis model.

Crohn's disease is a chronic inflammatory bowel disease characterized by inflammation of both the small and large intestines. Methotrexate (MTX), a classical dihydrofolate reductase (DHFR) inhibitor, has been used as a therapeutic agent in the treatment of patients with Crohn's disease in recent years. We sought to develop antifolates similar in structure to MTX that would be effective in reducing inflammation in a mouse disease model of colitis. Four classical DHFR inhibitors encompassing ester bridges in the central parts of the molecules were synthesized. These antifolates were efficient inhibitors of the DHFR enzyme derived from rat. They were also tested in vitro for their ability to inhibit induced proliferation of lymphocytes from mouse spleen. Inhibition of cell proliferation was achieved only in the micromolar range, whereas MTX was effective at low nanomolar concentrations. One of the DHFR inhibitors (1), with an IC(50) value for rlDHFR approximately 8 times higher than that of methotrexate, was selected for in vivo experiments in an experimental colitis model in mice. This compound demonstrated a clear antiinflammatory effect after topical administration, comparable to the effect achieved with the glucocorticoid budesonide. Three parameters were evaluated in this model: myeloperoxidase activity, colon weight, and inflammation scoring. A favorable in vivo effect of compound 1 (15 mg/(kg.day)) was observed in all three inflammatory parameters. However, the results cannot be explained fully by DHFR inhibition or by inhibition of lymphocyte cell proliferation, suggesting that other yet unidentified mechanisms enable reduction of inflammation in the colitis model. The mechanism of action of methotrexate analogues encompassing a bridging ester group is not well understood in vivo but seems to lend itself well to further development of similar compounds.

Animals↗