Peritoneal lymphatic uptake of fibrinogen and erythrocytes in the rat

Abstract

Intact and thoracic duct-cannulated rats were dialyzed at various intraperitoneal pressures with 5% bovine serum albumin solutions containing 125I-fibrinogen or 51Cr-erythrocytes. Lymphatic transport rates were calculated from the mass of tracer passing into the plasma space as function of tracer concentration in the peritoneal fluid during dialysis periods ranging between 143 and 360 min. Peritoneal protein concentrations were constant over the duration of the experiments. The calculated lymph flow rate was independent of intraperitoneal pressure and in intact rats averaged 2.85 +/- 1.22 microliters/min for uptake of 125I-fibrinogen and 2.60 +/- 1.17 for uptake of 51Cr-erythrocytes. However, the observed fluid loss rates from the peritoneal cavity were sensitive to the intraperitoneal pressure and were 5 to 20 times the calculated lymph flow rate. Mass balance experiments in two rats dialyzed with 125I-fibrinogen indicated that a significant proportion (28%) of tracer leaving the peritoneal cavity is absorbed by the anterior muscle wall of the abdomen and is probably trapped there because of its large molecular weight. Results from 125I-fibrinogen and 51Cr-erythrocyte uptake experiments both indicated that only approximately 30% of the total lymphatic drainage of the peritoneal cavity passes through the thoracic duct in rats.

Contribution of lymphatic absorption to loss of ultrafiltration and solute clearances in continuous ambulatory peritoneal dialysis.

“…The calculated lymphatic absorption rate in this study is much higher than in prior reports (26,27) which determined the rate of lymphatic flow from the rate of mass transfer to radio-labeled tracer from the peritoneal cavity to the blood. This latter method underestimates lymphatic drainage since a significant proportion of the small quantity of radio-labeled colloid administered remains in the subperitoneal interstitium (5) and after systemic absorption the tracer equilibrates out of the blood volume (28). It is possible that lymphatic absorption was higher in our studies than in active CAPD patients because the studies were performed in the supine position and fluid contact with the diaphragm may have been more extensive than in the upright posture.…”

“…The end lymphatics of the peritoneal cavity, located mainly on the undersurface of the diaphragm (3,4), continuously drain intraperitoneal fluid by bulk transport (5) and return the absorbed fluid to the venous circulation via the right lymph duct (70-80%) and thoracic duct (20-30%) (6). Thus, assuming intraperitoneal residual volume remains constant, the net ultrafiltration (UF) volume at the end of an exchange equals cumulative net transcapillary water transport minus lymphatic absorption during the exchange, and drain volume equals infusion volume ofdialysis solution plus cumulative net transcapillary UF minus lymphatic drainage.…”

Quantification of osmotic water transport in vivo using fluorescent albumin

“…Conversely, increasing IPP by external abdom- inal compression results in a significant reduction in tracer mass recovery in the dialysate, and a parallel increase in tracer appearance in the plasma and in the peritoneal membrane. In other rodent models of PD, disappearance of the macromolecular IPV tracer (RISA, dextrans, or autologous hemoglobin) from the peritoneal cavity (up to 10 -30%) can occur as a result of an uptake into lymphatic vessels (mainly subdiaphragmatic) and interstitial tissues lining the peritoneal cavity (10,34). In those models, transperitoneal transport of macromolecules from dialysate to plasma indeed depends on the nature of the tracer (5,17) and, more importantly, on IPP, which directly determines tracer disappearance (9,23,32,35).…”

Mechanism-Based Model of Parasite Growth and Dihydroartemisinin Pharmacodynamics in Murine Malaria

“…First, parasites and/or parasitized erythrocytes are rapidly absorbed after i.p. inoculation (T absp ϭ 0.0522 h), possibly via the lymphatic system (37)(38)(39). Furthermore, the dominance in bioavailability of rings (F rng ϭ 0.568) is expected, since these are most likely to survive the inoculation process relative to early or late trophozoites (F Ͻ 0.11).…”