Plasmodium coatneyi: alterations of transcapillary escape rate and capillary permeability to fibrinogen in rhesus monkeys.

The transcapillary escape rate and plasma clearance of fibrinogen were studied in six rhesus monkeys infected with Plasmodium coatneyi as well as in six control monkeys using 131I-fibrinogen as a tracer. The mean transcapillary escape rate of fibrinogen in the infected group was significantly higher than that of the control group. Both plasma volume and plasma fibrinogen concentration were also elevated in the infected group, these resulting in a significantly higher intravascular fibrinogen mass, plasma clearance rate, and outflux of fibrinogen from the intravascular to the extravascular compartments. Both effective capillary pore area/unit path length available for restricted diffusion and the specific permeability coefficient of plasma fibrinogen in the infected monkeys were also found to be significantly higher than those of the control group. These findings indicated that there was an increased leakage of plasma fibrinogen from the circulation into the extravascular space which was due either to increased capillary surface area and/or to an increased capillary permeability in rhesus monkeys infected with P. coatneyi.