The present invention relates to an isolated population of cell suspension from a mammalian fetal pulmonary tissue, wherein said fetal pulmonary tissue is at a developmental stage corresponding to that of a human pulmonary organ/tissue at a gestational stage selected from a range of 20 to 22 weeks of gestation, and a conditioning protocol comprising Naphthalene treatment, for use in treating a disease or condition in which regeneration of epithelial, mesenchymal and/or endothelial tissue is beneficial in a subject in need thereof.
