Fuente: WIPO "tomato" The present invention refers to an ex vivo method to recellularize a perfusion decellularized extracellular matrix of an organ or of a portion of an organ, comprising providing said decellularized extracellular matrix of an organ or of a portion of an organ, and contacting said decellularized extracellular matrix of an organ or of a portion of an organ with a population of cells, preferably regenerative/progenitor cells, under conditions in which said population of cells, preferably regenerative/progenitor cells, engraft, multiply and/or differentiate within and on said decellularized extracellular matrix portion, wherein said conditions comprises: a. injecting or perfusing the cells into the decellularized extracellular matrix at a pressure of between 1 and 200 mmHg so as to engraft the cells in the said decellularized extracellular matrix; b. expand the cells by using a proliferation media; and c. differentiate the cells by using a differentiation media.