A 48-hour preservation of an isolated human uterus: endometrial responses to sex steroids**Supported by Consiglio Nazionale delle Ricerche grants 840215844 and 840042304.

Human uteri were perfused with Krebs-Ringer bicarbonate-glucose buffer with and without estrogens and progesterone for a period of up to 48hours to preserve a viable organ, which was responsive to hormones. Flow rates of 12 to 35ml/minute per artery were fully distributed into the organ, with pressure values ranging from 80 to 120mm Hg. Arteriovenous gradients of oxygen and carbon dioxide tensions as well as the levels of lactate, lactic dehydrogenase, and creatine kinase released in the perfusate, indicators of tissue ischemia or cell necrosis, showed a good preservation of the organ for up to 48hours. The light- and electron-microscopic examinations of endometrial and myometrial tissues taken before and during perfusion confirmed this result. The extracorporeal perfusion of uteri with buffer containing estrogens plus progesterone exhibited secretive modifications of the proliferative endometrium, thus suggesting the viability of the organ and its responsiveness to sex steroids.