PMC:17829 / 6977-9862 JSONTXT

{"project":"2_test","denotations":[{"id":"11178120-8345197-4390807","span":{"begin":1663,"end":1665},"obj":"8345197"},{"id":"11178120-7542307-4390808","span":{"begin":1666,"end":1668},"obj":"7542307"}],"text":"Results:\nIn initial experiments we studied the time course of PBMC migration into plain or EC-coated collagen gels, respectively. As shown in Fig. 1, the presence of an endothelium clearly facilitated the migration of PBMCs: after 30 minutes the percentage of PBMCs that had migrated was twice as high as that in the absence of ECs. After 2 hours, about 40% of the PBMCs could be recovered from collagen gels coated with an EC layer, whereas only 24% of PBMCs had migrated into plain collagen gels. Prolonging the incubation time to 24 hours allowed further migration of PBMCs only in the absence of ECs, but did not significantly increase the extent of EC-mediated migration.\nThe results and the statistical evaluation of the phenotypic analysis of monocytes recovered in various fractions of the migration assay are shown in Table 2. The expression of CD11a, CD33, CD45RO, CD54 and HLA-DR was significantly higher in MIG than in NAD. When compared with BND, these markers, and also CD45RB and CD62L, were significantly elevated in MIG. NAD, BND and MIG were incubated with collagenase for the same durations to control for possible cell activation by the collagenase treatment; the expression of adhesion molecules was similar to that on untreated cells.\nWe also studied the capacity for monocyte migration into plain collagen gels, that is, in the absence of an endothelium. No significant difference in surface marker expression was observed when migrated monocytes were compared with any other fraction.\nIt has been reported that cytokines such as TNF-α, IL-1α and IFN-γ and also the chemokine MIP-1α can enhance the transendothelial migration of monocytes [19,20]. We were therefore interested to investigate whether pretreatment of the ECs with these factors would be sufficient to enhance the transendothelial migration of monocytes and/or to induce changes in their expression of surface markers. Figure 2 shows that pretreatment of the endothelium with any of the cytokines led to a consistent and significant increase in the number of migrated mononuclear cells in comparison with simultaneously performed control experiments in which the endothelium was not pretreated. Pretreatment with IL-1α was the most effective, resulting in a 132% increase in migrated cells (P \u003c 0.001). The respective values for the other cytokines were as follows: MIP-1α, 194% (P = 0.043); TNF-α, 193% (P = 0.006); IFN-γ, 136% (P = 0.016).\nPretreatment of ECs with TNF-α led to a significant decrease in CD45RO and HLA-DR on migrated monocytes. In contrast, CD54 (ICAM-1) was significantly increased on monocytes that migrated through endothelium pretreated with TNF-α or IL-1α in comparison with migration through untreated endothelium (Figs 3 and 4, Table 3).\nWhen ECs were pretreated with IFN-γ or MIP-1α, no statistically significant change in monocyte surface markers was observed (Table 3)."}