Controlled perfusion of a vascularized microenvironment within a 3D printed bioreactor to study leukemia cells trafficking ex-vivo

Chronic Lymphocytic Leukemia (CLL) is the most common adult leukemia in Western countries, marked by the accumulation of CD5 ⁺ B cells in blood and lymphoid tissues. The vascular system plays a critical role, as malignant cells interact with endothelial cells through poorly understood mechanisms. To study CLL dissemination, we developed VesselBox, a modular bioreactor for selective perfusion of a milli-scale vessel-like structure within a lymphoid microenvironment scaffold, created using 3D bioprinting and casting. Numerical simulations optimized perfusion parameters for cell homeostasis. Vessel maturation, confirmed by endothelial markers (CD31, Ve-cadherin, Von Willebrand Factor, collagen IV), showed VesselBox sustains perfusion for up to 7 days. By recirculating CLL cells, we validated its use for studying extravasation and immunophenotype characterization. This pioneering device enables ex vivo analysis of CLL dissemination, offering potential to uncover new therapeutic targets by examining circulating and extravasated cells with or without drugs.