To move towards clinical applications, tissue engineering (TE) should be validated with human primary cells and offer easy connection to the native vascularisation. Based on a sheet-like bone substitute developed previously, we investigated a mesenchymal stem cells / endothelial cells (MSCs/ECs) coculture to enhance pre-vascularisation. Using MSCs from 6 independent donors, we focused on donor variability and cell crosstalk. Coculture was performed on calcium phosphate granules in a specific chamber (one month). MSCs were seeded first then ECs were added after two weeks, with control monocultures. Cell viability and organisation (fluorescence, electronic microscopy), differentiation (ALP staining/activity, RT-qPCR) and mechanical cohesion were analysed. Adaptation of the protocol to coculture was validated (high cell viability and proliferation). Activity and differentiation showed strong trends towards synergistic effects between cell types. MSCs reached early mineralization stage of maturation. The delayed ECs addition ECs allowed for their attachment on developed MSCs. The main impact of donor variability could be the lack of cell proliferation potential with some donors, leading to low differentiation and mechanical cohesion and therefore absence of sheet-like shape successfully obtained with others. We suggest adapting protocols to cell proliferation potentials from one batch of cells to the other in a patient-specific approach.