Terminal lymphatics: the potential "lethal corner" in the distribution of tissue pO2.
BACKGROUND
Terminal lymphatic fluid is the compartment furthest removed from the oxygen supply, and therefore should present the lowest pO(2) in the tissue due to oxygen consumption by the tissue and the lymphatic vessel wall.


RESULTS
The distribution of pO(2) was determined in the tissue, the lymphatic microvessels, and arterioles and venules of the hamster chamber window model, which is studied without anesthesia with the tissue isolated from the environment. Lymphatic fluid pO(2) was measured with the phosphorescence oxygen quenching method. Small terminal lymphatic fluid pO(2) was 18.4 +/- 2.6 mmHg, and 18.0 +/- 2.4 mmHg in collecting lymphatics. Tissue pO(2) averaged 24.6 +/- 2.7 mmHg. The significant difference between tissue and intralymphatic pO(2) was due in part to the presence of an oxygen gradient across the lymphatic wall, which ranged from 3.7 +/- 1.3 mmHg for terminal lymphatics, to 6.0 +/- 1.2 mmHg for collecting lymphatics. This gradient is assumed to be due to the oxygen consumption by the cellular component of the lymphatic wall.


CONCLUSIONS
The increased vessels wall gradient found in collecting lymphatics was reconciled by the findings that these microlymphatic vessels tend to be contiguous to the arterioles, whereas the terminal lymphatics are dispersed in the tissue. These findings indicate that terminal lymphatic present the lowest oxygen tension in the tissue, and therefore are the locations at risk to develop anoxia when the microvascular oxygen supply becomes limited.
Hangai-Hoger
Nanae
N
Department of Bioengineering, University of California, San Diego, La Jolla, California 92093-0412, USA. nanaeh@earthlink.net
Tsai
Amy G
AG
Cabrales
Pedro
P
Intaglietta
Marcos
M
D000818:Animals; D006224:Cricetinae; D008196:Lymph / Q000737:chemistry / Q000378:metabolism*; D008208:Lymphatic System / Q000502:physiology*; D042601:Lymphatic Vessels / Q000033:anatomy & histology / Q000502:physiology; D008647:Mesocricetus; D010100:Oxygen / Q000032:analysis / Q000378:metabolism*; D010313:Partial Pressure; D014018:Tissue Distribution
D010100:Oxygen