TY - JOUR
T1 - Human thoracic duct in vitro
T2 - diameter-tension properties, spontaneous and evoked contractile activity
AU - Telinius, Niklas
AU - Drewsen, Nanna
AU - Pilegaard, Hans
AU - Kold-Petersen, Henrik
AU - de Leval, Marc
AU - Aalkjaer, Christian
AU - Hjortdal, Vibeke
AU - Boedtkjer, Donna Briggs
PY - 2010/9
Y1 - 2010/9
N2 - The current study characterizes the mechanical properties of the human thoracic duct and demonstrates a role for adrenoceptors, thromboxane, and endothelin receptors in human lymph vessel function. With ethical permission and informed consent, portions of the thoracic duct (2-5 cm) were resected and retrieved at T(7)-T(9) during esophageal and cardia cancer surgery. Ring segments (2 mm long) were mounted in a myograph for isometric tension (N/m) measurement. The diameter-tension relationship was established using ducts from 10 individuals. Peak active tension of 6.24 +/- 0.75 N/m was observed with a corresponding passive tension of 3.11 +/- 0.67 N/m and average internal diameter of 2.21 mm. The equivalent active and passive transmural pressures by LaPlace's law were 47.3 +/- 4.7 and 20.6 +/- 3.2 mmHg, respectively. Subsequently, pharmacology was performed on rings from 15 ducts that were normalized by stretching them until an equivalent pressure of 21 mmHg was calculable from the wall tension. At low concentrations, norepinephrine, endothelin-1, and the thromboxane-A(2) analog U-46619 evoked phasic contractions (analogous to lymphatic pumping), whereas at higher contractions they induced tonic activity (maximum tension values of 4.46 +/- 0.63, 5.90 +/- 1.4, and 6.78 +/- 1.4 N/m, respectively). Spontaneous activity was observed in 44% of ducts while 51% of all the segments produced phasic contractions after agonist application. Acetylcholine and bradykinin relaxed norepinephrine preconstrictions by approximately 20% and approximately 40%, respectively. These results demonstrate that the human thoracic duct can develop wall tensions that permit contractility to be maintained across a wide range of transmural pressures and that isolated ducts contract in response to important vasoactive agents.
AB - The current study characterizes the mechanical properties of the human thoracic duct and demonstrates a role for adrenoceptors, thromboxane, and endothelin receptors in human lymph vessel function. With ethical permission and informed consent, portions of the thoracic duct (2-5 cm) were resected and retrieved at T(7)-T(9) during esophageal and cardia cancer surgery. Ring segments (2 mm long) were mounted in a myograph for isometric tension (N/m) measurement. The diameter-tension relationship was established using ducts from 10 individuals. Peak active tension of 6.24 +/- 0.75 N/m was observed with a corresponding passive tension of 3.11 +/- 0.67 N/m and average internal diameter of 2.21 mm. The equivalent active and passive transmural pressures by LaPlace's law were 47.3 +/- 4.7 and 20.6 +/- 3.2 mmHg, respectively. Subsequently, pharmacology was performed on rings from 15 ducts that were normalized by stretching them until an equivalent pressure of 21 mmHg was calculable from the wall tension. At low concentrations, norepinephrine, endothelin-1, and the thromboxane-A(2) analog U-46619 evoked phasic contractions (analogous to lymphatic pumping), whereas at higher contractions they induced tonic activity (maximum tension values of 4.46 +/- 0.63, 5.90 +/- 1.4, and 6.78 +/- 1.4 N/m, respectively). Spontaneous activity was observed in 44% of ducts while 51% of all the segments produced phasic contractions after agonist application. Acetylcholine and bradykinin relaxed norepinephrine preconstrictions by approximately 20% and approximately 40%, respectively. These results demonstrate that the human thoracic duct can develop wall tensions that permit contractility to be maintained across a wide range of transmural pressures and that isolated ducts contract in response to important vasoactive agents.
KW - 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid/pharmacology
KW - Acetylcholine/pharmacology
KW - Adrenergic alpha-Agonists/pharmacology
KW - Endothelin-1/pharmacology
KW - Humans
KW - Isometric Contraction/drug effects
KW - Myography
KW - Norepinephrine/pharmacology
KW - Receptors, Adrenergic/metabolism
KW - Thoracic Duct/drug effects
KW - Vasoconstrictor Agents/pharmacology
KW - Vasodilator Agents/pharmacology
U2 - 10.1152/ajpheart.01089.2009
DO - 10.1152/ajpheart.01089.2009
M3 - Journal article
C2 - 20511415
VL - 299
SP - H811-8
JO - A J P: Heart and Circulatory Physiology (Online)
JF - A J P: Heart and Circulatory Physiology (Online)
SN - 1522-1539
IS - 3
ER -