Long-term dual perfusion of isolated human placental lobules with improved oxygenation for infectious diseases research.

An improved method for long-term perfusion of the isolated human term placental lobule has been developed to investigate the maternofetal transfer of infectious agents, in particular the human immunodeficiency virus (HIV). The purpose of this paper is to describe those modifications that allow for substantially prolonged perfusions in in a biohazard environment. The method described has been adapted from previous models. The perfusion apparatus has been modified for use within a biohazard hood, and, intravenous bags contain the medium for circulation of perfusates in closed circuits. A Mera Silox-S 0.3 membrane oxygenator delivers more oxygen to the tissue, and, Electromedic Cardioplegia heat exchangers warm the perfusate prior to oxygenation. Viability criteria (glucose consumption, lactate production, de novo production of human placental lactogen (hPL), volume loss, flow, temperature, pressure, oxygen transfer, carbon dioxide production, absence of IgM transfer and light and electron microscopy) demonstrate that the placental tissue remains in a functional state throughout the perfusion. Oxygen and glucose consumption are both stable over time; lactate levels remain constant; and hPL continues to be produced. These significant modifications of the perfusion system have permitted the investigators to increase the duration of perfusion to 48 h while preserving normal metabolic function of ultrastructurally intact tissue as demonstrated by ultra structural observations. This perfusion model device provides biohazard precautions and may be applied to other studies of placental physiology.