K Nieber

Differences between retinal and choroidal microvascular endothelial cells (MVECs) under normal and hypoxic conditions.

The morphological and functional differences between the retinal and choroidal vascular bed raise the question of whether the smallest functional unit, the microvascular endothelial cell (MVEC), also differs in its basal characteristics. Here, we examined bovine retinal and choroidal MVECs (rMVECs, cMVECs) for the presence and regulation of angiogenic mediators and their receptors, and cytokines at the mRNA level using quantitative RT-PCR and differential display. Vascular endothelial growth factor (VEGF) mRNA was expressed in both rMVECs and cMVECs. The basal and hypoxia-increased VEGF mRNA levels were significantly higher in cMVECs, which may indicate a higher capacity for autocrine stimulation in these cells. The mRNA for two VEGF receptors, Flt-1 and Flk-1, was present in rMVECs and cMVECs. Interestingly, rMVECs expressed higher Flt-1 but lower Flk-1 mRNA levels compared to cMVECs. Examining the angiopoietin (Ang)/Tie-2 system, we only detected Ang-1 mRNA at very low levels. While Ang-2 mRNA levels were high in both rMVECs and cMVECs, rMVECs expressed 2-3 times the basal and hypoxia-upregulated Ang-2 mRNA levels than did cMVECs. No difference was found in basal Tie-2 mRNA levels. rMVECs are the more potent producers of macrophage colony-stimulating factor (M-CSF) and granulocyte-macrophage CSF (GM-CSF), whereas cMVECs expressed higher RANTES mRNA levels. In our second approach - screening rMVECs and cMVECs for differentially expressed genes - we found liprin-beta1, calnexin, and sushi-repeat-containing protein, x chromosome (SRPX) mRNA in both MVEC types at varying levels. In summary, MVECs from the retinal and choroidal vascular beds showed quantitative differences in angiogenic regulator expression and in their capability to produce cytokines.

Joint action of herbal components influence the effects of STW 5 on inflammatory processes and disturbed motility

STW 5 (Iberogast®) contains nine herbal extracts affecting inflammatory processes and disturbed motility in the gut. The aim of the study was to investigate the effect of individual ethanolic extracts (in concentration used in STW 5) and selected combinations on targets related to inflammation. Cytotoxicity was examined in CaCo-2 cells using the lactate dehydrogenase (LDH) assay. THP-1 cells were used to determine TNFα release using an ELISA. ACh-induced contractions of rat ileum preparations were measured in an organ bath setup. STW 5 (500 µg/ml), STW 5-II (5.1 µg/ml, containing only 6 of the 9 extracts) and lemon balm (59.9 µg/ml) reduced LPS (10 ng/ml)-induced LDH leakage from CaCo-2 cells by 74 – 75%. Iberis amara (29.1 µg/ml), peppermint (38.9 µg/ml), chamomile (116.3 µg/ml), angelica (84.7 µg/ml) and milk thistle (15.2 µg/ml) inhibited LDH leakage by 25 – 37%. Liquorice (84.9 µg/ml), caraway (30.9 µg/ml) and celandine (61.9 µg/ml) had no effect. The combinations of Iberis amara and peppermint as well as peppermint and milk thistle revealed synergistic or additive effects, whereas the combination of chamomile and angelica evoked additive or antagonistic effects depending on their compositions. STW 5, STW 5-II, Iberis amara, peppermint, liquorice, caraway, milk thistle and lemon balm in concentration used in the LDH assay inhibited LPS (100 ng/ml)-induced TNFα release to 51 – 67%. The combinations of Iberis amara and peppermint as well as chamomile and liquorice had additive or antagonistic effects depending on their compositions. STW 5 and STW 5-II reduced the acetylcholine (ACh)-induced contractions in rat ileum preparations to 81 – 83%. The individual extracts inhibited the contractions to 83 – 91% except lemon balm. The combination of Iberis amara and peppermint as well as liquorice and caraway had additive or antagonistic effects depending on the ratios. Our results highlighted the interactions between the extracts of STW 5 and confirm the concept of multi-target actions. Keywords: Iberogast, Cytotoxixity, TNF-alpha, CaCo-2 cells, THP-1 cells, synergy, drug interaction