A process for the production of an engineered vascular tissue or construct comprising a scaffold having a lumen coated with a functional and continuous endothelium having a confluent cell monolayer, for testing medical or veterinary products, said process comprising the application of: - a method for seeding an endothelial cell culture into the lumen of a scaffold to yield a seeded scaffold; said seeded scaffold being present inside a bioreactor, to yield a seeded bioreactor -scaffold system; wherein said seeding method comprises the steps of: - releasing said endothelial cell culture in the form of a cell suspension comprising a fresh culture medium and endothelial cells inside a container mounted on a T connector located upstream of the bioreactor by a rotary connector; followed by - releasing said endothelial cell culture into the lumen of the scaffold inside the bioreactor chamber with a continuous flow such that the flow velocity permits said cell suspension to descend into the T connector without generating air bubbles and push the air bubbles inside the lumen of the scaffold towards an opening of a T connector located downstream of the bioreactor enabling them to exit; and successively, - a perfusion method with a fresh culture medium having a temperature between 30°C and 45°C, preferably 37°C, of the endothelial cells present in the lumen of said seeded scaffold; said perfusion method being realised by the connection of a perfusion circuit or (51-57 and BT) to said seeded bioreactor -scaffold system; wherein said perfusion method comprises a step of: - partly filling an element for the removal of the air bubbles or present in the perfusion circuit with said fresh culture medium, wherein said element for the removal of the bubbles or comprises a chamber, a cap closing said chamber, an inlet access and an outlet access, wherein said element for the removal of the air bubbles (71 or BT) has a volume and wherein a first part of said volume is filled with said fresh culture medium and wherein a second part of said volume is filled with air, said second part of said volume having the function of trapping the air bubbles present in said fresh culture medium which flows through said inlet access and said outlet access. - a method for seeding an endothelial cell culture into the lumen of a scaffold to yield a seeded scaffold; said seeded scaffold being present inside a bioreactor, to yield a seeded bioreactor -scaffold system; - releasing said endothelial cell culture in the form of a cell suspension comprising a fresh culture medium and endothelial cells inside a container mounted on a T connector located upstream of the bioreactor by a rotary connector; followed by - releasing said endothelial cell culture into the lumen of the scaffold inside the bioreactor chamber with a continuous flow such that the flow velocity permits said cell suspension to descend into the T connector without generating air bubbles and push the air bubbles inside the lumen of the scaffold towards an opening of a T connector located downstream of the bioreactor enabling them to exit; - a perfusion method with a fresh culture medium having a temperature between 30°C and 45°C, preferably 37°C, of the endothelial cells present in the lumen of said seeded scaffold; said perfusion method being realised by the connection of a perfusion circuit or (51-57 and BT) to said seeded bioreactor -scaffold system; - partly filling an element for the removal of the air bubbles or present in the perfusion circuit with said fresh culture medium, wherein said element for the removal of the bubbles or comprises a chamber, a cap closing said chamber, an inlet access and an outlet access, wherein said element for the removal of the air bubbles (71 or BT) has a volume and wherein a first part of said volume is filled with said fresh culture medium and wherein a second part of said volume is filled with air, said second part of said volume having the function of trapping the air bubbles present in said fresh culture