Does an unfavorable metabolic environment for red cells develop within the cat spleen when abnormal cells become trapped?

Abstract

Intrasplenic pH, blood gas tensions, and glucose concentration were deduced from measurements of blood drained from cat spleen during contraction with the inflow occluded. During this procedure the hematocrit of the outflow rises gradually from 35% to 40% (arterial) to 75% to 80%, the last fraction representing a pure sample of blood from the splenic pulp. In normoxic animals no evidence was found of an unfavorable metabolic environment for red cells within the spleen on account of low pH, low O2 tension, and substrate deprivation, as is generally believed. However, red cell flow through the red pulp can be impeded rheologically after sequestration of 10(9) heat-treated (HT) autologous red cells, and we have tested the hypothesis that under these conditions the availability of O2 and glucose might be reduced and a decline in pH might occur. One hour after injection of the HT cells into the splenic artery, splenic contraction was induced with the arterial inflow occluded; the blood expelled from the splenic vein was collected anaerobically as successive 1 ml fractions. Values of pH, O2 tension, and glucose concentration in the final samples expelled were not significantly different from those in corresponding samples from control spleens. Thus, even when stasis of 50% of intrasplenic red cells occurs, caused by the sequestration of 10(9) abnormal cells, no hostile metabolic environment develops within the red pulp. Presumably the residual plasma flow through the pulp is sufficient to maintain a normal metabolic environment.