Hyaluronan in prenodal lymph from skin: changes with lymph flow.

Hyaluronan, an important structural component of the interstitial matrix in skin, is found in lymph to be subsequently degraded in lymph nodes and liver. Hyaluronan concentration and flux were measured in prenodal lymph from the hindpaw in six pentobarbital-anesthetized mongrel dogs at normal and increased transvascular fluid flux. Lymph flow and hyaluronan concentration in control averaged 16.3 +/- 15.0 (SD) microliters/min (range 6.3-46.5) and 6.16 +/- 3.78 micrograms/ml, respectively. Lymph flow was increased stepwise by raising venous pressure, and measurements were performed at each step after three consecutive and identical measurements of lymph flow and protein concentration taken 15 min apart. Hyaluronan concentration was unchanged until venous pressure was raised above 20 mmHg and then gradually fell to an average of 4.8 +/- 2.67 micrograms/ml at venous pressures around 40 mmHg. The lymphatic hyaluronan flux averaged 0.085 +/- 0.034 micrograms/min in control and 0.28 +/- 0.14 micrograms/min at the highest flows (4.3 times control), draining 2% and 10% of the total interstitial hyaluronan in the tissue in 24 h, respectively. The results suggest that at least part of the hyaluronan in skin is loosely bound and easily removed via lymph.