Effects of magnetic resonance imaging contrast agents on human umbilical vein endothelial cells and evaluation of magnetic resonance imaging contrast media-triggered transforming growth factor-beta induction in dermal fibroblasts (HSF) as a model for nephrogenic systemic fibrosis.

RATIONALE AND OBJECTIVES: The objective of this study was to evaluate effects of 6 commercially available magnetic resonance contrast media (CM) on human umbilical vein endothelial cells (HUVEC) and the induction of transforming growth factor-beta (TGF-ß) in dermal fibroblasts (HSF) as a possible model for the pathogenesis of nephrogenic systemic fibrosis. METHODS: HUVECs were incubated with 10× and 20× of the molar standard blood concentration achieved with CM applications for magnetic resonance imaging examinations (10× and 20× concentration) for 24 hours using gadolinium-based CM Gadovist, Magnevist, Multihance, and Omniscan, as well as Teslascan (Manganese-based), and Resovist (Iron-based). Proliferation kinetics (PK), colony formation, and viability assays were performed. Additionally, human dermal fibroblasts (HSF) were incubated for 24 hours with 1× and 20× concentration in all 6 CM, and TGF-ß levels were assessed directly after the incubation period as well as on days 3 and 8 postincubation. RESULTS: HUVEC PK data show similar gains in cell numbers for all 6 CM in both concentration groups over the 17-day assessment period. Only cells incubated with Omniscan and Teslascan differed from the other groups on days 3 and 7 postincubation (P < 0.05). After day 7, a cell regain occurred in the Omniscan and Teslascan groups reaching the numbers of the other groups in sequel. Differences in colony formation were consistent with PK results with a statistically significant reduction in clonogenic activity for Teslascan and Omniscan in HUVEC cells, P < 0.05. No reduction in viability was seen for all groups and conditions. TGF-ß expression of HSF cells incubated with 1× concentration and all CM did not differ significantly from control cells for any point in time investigated. At 20× concentration directly after incubation, TGF-ß was significantly reduced for the Teslascan and Resovist group as 3 compared with control and all other CM groups, P < 0.05. On day 3 postincubation, only Resovist-incubated HSF cells showed a significant reduction of TGF-ß (1.614, standard deviations: 89) as compared with the control group (2.883, standard deviations: 30) and the other CM. TGF-ß was slightly reduced for all CM groups 8 days after incubation (not statistically significant, P > 0.05). CONCLUSIONS: After 24 hours of incubation with Omniscan and Teslascan (10× and 20× concentration), considerable short-term antiproliferative effects in HUVECs were observed. HSF cells (20× concentration) showed a reduction of TGF-ß for Resovist and Teslascan directly after incubation, whereas TGF-ß levels in HSF cells were slightly reduced for all CM 8 days after incubation. Therefore, TGF-ß-mediated proliferative effects on fibroblasts or on collagen synthesis potentially leading to nephrogenic systemic fibrosis may mainly be triggered by tissue monocytes and macrophages in the peripheral blood instead of dermal fibroblasts.

Effects of MRI contrast agents on human embryonic lung fibroblasts.

RATIONALE AND OBJECTIVES: The objective of this investigation was to evaluate 6 magnetic resonance contrast media (CM) with regard to their different effects on human embryonic lung fibroblasts (HEL-299). METHODS: Human embryonic fibroblasts (HEL-299) were incubated with 1x, 5x, 10x, and 20x of the normal molar blood concentration (1x, 5x, 10x, 20x conc.) reached through routine contrast media applications for MRI examinations. Four gadolinium-based CM, ie, Gadovist, Magnevist, Multihance, Omniscan, Teslascan (Manganese-based), and Resovist (Iron-based), with incubation periods over 4 hours and 24 hours were investigated. Proliferation kinetics, colony formation, and viability assays were performed after 4 and 24 hours of treatment. Apoptotic cells were quantified after tetramethylrhodamine ethyl ester staining following 24 hours of CM media incubation (20x conc.) by fluorescence activated cell sorting cytometry. Furthermore, immunofluorescence images with vimentin staining were obtained (20x conc., 24 hours treatment). Cell cycle analysis was performed after 24 hours of incubation and 20x conc. directly after incubation and 24 hours later (fluorescence activated cell sorting cytometry). RESULTS: The proliferation kinetics performed with 20x conc. revealed a persistent increase in cell numbers until day 11 for all CM without significant differences after 4 hours of incubation. A significant reduction in initial cell numbers was recorded in the 24-hours-group after 4 days of CM incubation with Magnevist, Multihance, Omniscan, and Teslascan. Solely cells incubated with Resovist and Gadovist failed to show decreased cell numbers when compared with the control group. However, a considerable cell regain occurred afterward reaching control-group levels on day 21. Colony numbers were significantly reduced (about 20%, respectively) with Magnevist at 10x and 20x conc., as well as Omniscan and Multihance at 20x conc. when compared with all other groups, P < 0.05. Cell-cycle distribution showed a reduction of S-phase cells for Magnevist, Omniscan, and Multihance (2.9%-10.5%) when compared with Gadovist, Resovist and Teslascan (16.7%-21.0%). Twenty-four hours after incubation, the percentiles of cells in S-phase were significantly increased for Magnevist, Omniscan, and Multihance (31.4%-38.5%) when compared with Gadovist, Resovist, and Teslascan (18.6%-26.8%), P < 0.05. Viability was not impaired by administration of any CM and no apoptosis was seen after tetramethylrhodamine ethyl ester staining at 24 hours of incubation. Cell morphology remained unchanged in vimentin-staining for all CM and conditioning regimens. CONCLUSIONS: No toxic effects on embryonic fetal lung fibroblasts were detectable after 4 and 24 hours of incubation in 6 MRI CM and 10x to 20x conc. in our setting. Antiproliferative effects, initially detected with Magnevist, Omniscan and Multihance, were rapidly compensated for.