Morphometry and mathematical modelling of the capillary-like patterns formed in vitro by bone marrow macrophages of patients with multiple myeloma

Under angiogenic stimulation monocytes/macrophages develop an endothelial phenotype with the expression of specific surface markers and even form cord- and tubular-like structures in vitro, suggesting that this leucocyte population may be recruited for vasculogenesis. We have demonstrated that bone marrow macrophages of mutiple myeloma (MM) patients exposed to well known angiogenic cytokines, namely vascular endothelial growth factor (VEGF) and fibroblast growth factor-2 (FGF-2) transformed into cells phenotypically similar to paired MM endothelial cells (MMEC) and gave vessels-like structures overlapping those produced by MMEC. Here, a quantitative, morphometric, approach was applied to characterize the vasculogenic potential of macrophages isolated from bone marrow of patients with MM by testing them in vitro in the Matrigel assay and comparing the patterns they formed with those generated by their normal endothelial counterpart. Moreover, a mathematical model of the self-assembly of the cells was elaborated to characterize the relationship between a set of cellular and biochemical parameters and the structure of the patterns formed by MMEC and MM macrophages in vitro.