A tube system (1) for reconstructing a hollow organ, comprising a tube (2) for draining a substance, like e.g. urine, wherein the tube (2) for draining the substance is arranged within an outer tube (5) and that the space (4) between the two tubes (2, 5) is provided for the application of cells, and wherein the outer tube (5) is formed by a membrane (5) permeable for the cells to be applied, in particular a micro-perforated membrane (5).