pro-angiogenic cd14++ cd16+ cd163+ monocytes accelerate the in vitro endothelialization of soft hydrophobic poly(n-butyl acrylate) networks

as the majority of the polymers used as cardiovascular grafts so far do not match the elasticity of human arteries (100–1000 kpa) and the required endothelialization, a multifunctional material approach is needed to allow the adjustment of the mechanical properties while at the same time exhibiting a haemocompatible surface. recently soft poly(n-butyl acrylate) networks (cpnba) with adjustable mechanical properties were introduced as candidate materials with a surface that can be endothelialized. in this study, angiogenically stimulated intermediate cd163⁺ monocytes/macrophages (amo2) were utilized as a cellular cytokine release system to realize the functional endothelialization of the hydrophobic cpnba surface. we investigated the influence of co-cultured amo2 on the morphology, density and cytokine secretion of human umbilical venous endothelial cells (huvec) seeded on cpnba with an elastic modulus of around 250 kpa (cpnba0250). a functional confluent huvec monolayer could be developed in the co-culture within 3 days. in contrast, the huvec in the monoculture exhibited stress fibres, broadened marginal filament bands and significantly more and larger cell-free areas in the monolayer, indicating incomplete cell–substrate binding. remarkably, a functional confluent monolayer formation could only be achieved in co-cultures; it did not develop with the sole supplementation of recombinant vegf-a₁₆₅ to the huvec monocultures (unpublished data). the study demonstrated the multifunctional potential of cpnba in combination with amo2 as a cellular cytokine release system, adapting their secretion to the demand of huvec. in this way, a functional confluent monolayer could be generated within 3 days.