scholarly journals Silence of the lymphs: some anaesthetic regimens inhibit lymphatic pumping

2019 ◽  
Vol 597 (11) ◽  
pp. 2827-2828 ◽  
Author(s):  
Katarina J. Ruscic ◽  
Timothy P. Padera
Keyword(s):  
Lymphatic Pumping

scholarly journals The relationship between lymphangion chain length and maximum pressure generation established through in vivo imaging and computational modeling

2017 ◽  
Vol 313 (6) ◽  
pp. H1249-H1260 ◽  
Author(s):  
Mohammad S. Razavi ◽  
Tyler S. Nelson ◽  
Zhanna Nepiyushchikh ◽  
Rudolph L. Gleason ◽  
J. Brandon Dixon
Keyword(s):  
Nitric Oxide ◽  
Smooth Muscle ◽  
Minimally Invasive ◽  
Chain Length ◽  
Maximum Pressure ◽  
Computational Simulations ◽  
A Chain ◽  
Lymphatic Pumping ◽  
The Relationship

The intrinsic contraction of collecting lymphatic vessels serves as a pumping system to propel lymph against hydrostatic pressure gradients as it returns interstitial fluid to the venous circulation. In the present study, we proposed and validated that the maximum opposing outflow pressure along a chain of lymphangions at which flow can be achieved increases with the length of chain. Using minimally invasive near-infrared imaging to measure the effective pumping pressure at various locations in the rat tail, we demonstrated increases in pumping pressure along the length of the tail. Computational simulations based on a microstructurally motivated model of a chain of lymphangions informed from biaxial testing of isolated vessels was used to provide insights into the pumping mechanisms responsible for the pressure increases observed in vivo. These models suggest that the number of lymphangions in the chain and smooth muscle cell force generation play a significant role in determining the maximum outflow pressure, whereas the frequency of contraction has no effect. In vivo administration of nitric oxide attenuated lymphatic contraction, subsequently lowering the effective pumping pressure. Computational simulations suggest that the reduction in contractile strength of smooth muscle cells in the presence of nitric oxide can account for the reductions in outflow pressure observed along the lymphangion chain in vivo. Thus, combining modeling with multiple measurements of lymphatic pumping pressure provides a method for approximating intrinsic lymphatic muscle activity noninvasively in vivo while also providing insights into factors that determine the extent that a lymphangion chain can transport fluid against an adverse pressure gradient. NEW & NOTEWORTHY Here, we report the first minimally invasive in vivo measurements of the relationship between lymphangion chain length and lymphatic pumping pressure. We also provide the first in vivo validation of lumped parameter models of lymphangion chains previously developed through data obtained from isolated vessel testing.

HEMOGLOBIN AS A MODULATOR OF LYMPHATIC PUMPING FOLLOWING TISSUE INJURY AND SHOCK

1991 ◽  
Vol 31 (7) ◽  
pp. 1047
Author(s):  
M. G. Johnston ◽  
R. Elias ◽  
G. Wandolo ◽  
J. Eisenhoffer
Keyword(s):  
Tissue Injury ◽  
Lymphatic Pumping

Increased lymphatic pumping ability in pregnant ewes

1992 ◽  
Vol 167 (6) ◽  
pp. 1756-1759 ◽  
Author(s):  
Guillermo J. Valenzuela ◽  
Samuel Cheshier ◽  
Gabriel Hunt ◽  
Ramona Hunt
Keyword(s):  
Lymphatic Pumping

Effects of alpha-adrenergic stimuli on mesenteric collecting lymphatics in the rate

1997 ◽  
Vol 273 (1) ◽  
pp. R331-R336 ◽  
Author(s):  
J. N. Benoit
Keyword(s):  
Smooth Muscle ◽  
Stroke Volume ◽  
Contractile Activity ◽  
Tracking System ◽  
Video Tracking ◽  
Sprague Dawley ◽  
Shortening Velocity ◽  
Adrenoceptor Agonist ◽  
Lymphatic Pumping

The present study examined the effects of alpha 1- and alpha 2-adrenergic stimuli on rat mesenteric collecting lymphatics in vivo. Sprague-Dawley rats were anesthetized, and the mesentery was prepared for intravital microscopic study. Mesenteric collecting lymphatic diameter was continuously monitored by using a computerized video tracking system, and indexes of lymphatic pumping (e.g., contraction frequency, stroke volume, ejection fraction, and muscle shortening velocity) were determined from the diameter record. Contractile activity was monitored before and during the administration of various adrenergic agonists and antagonists. The receptor antagonists prazosin (alpha 1) and yohimbine (alpha 2) did not significantly alter baseline diameter or contractile activity, which suggests that lymphatics possess no basal adrenergic tone. Norepinephrine and phenylephrine (01-1.0 microM) produced dose-dependent increases in frequency and decreases in diameter. Lymphatic pump flow increased in direct proportion to frequency, because stroke volume did not change. The changes in lymphatic pumping produced by 1 microM norepinephrine were completely blocked by prazosin or phentolamine and only partially blocked by yohimbine. The alpha 2-adrenoceptor agonist (alpha-methyl-norepinephrine) produced no changes in lymphatic activity. This latter observation suggests that a role for postjunctional alpha 2-adrenoceptors in modulating mesenteric lymphatic smooth muscle is unlikely. The results of these studies support the existence of alpha-adrenoceptors on lymphatic smooth muscle. It is concluded that conditions characterized by increased sympathetic outflow may augment lymphatic function through alpha 1- but not alpha 2-adrenoceptors.

Role of endothelial cells in regulating hemoglobin-induced changes in lymphatic pumping

1992 ◽  
Vol 263 (6) ◽  
pp. H1880-H1887 ◽  
Author(s):  
R. M. Elias ◽  
J. Eisenhoffer ◽  
M. G. Johnston
Keyword(s):  
Endothelial Cells ◽  
Smooth Muscle ◽  
Inhibitory Effect ◽  
Direct Inhibitory Effect ◽  
Induced Changes ◽  
Lymphatic Pumping ◽  
Pumping Activity

Studies with a sheep isolated duct preparation in vivo demonstrated that the route of administration of hemoglobin was important in demonstrating its inhibitory effect on lymphatic pumping. With autologous oxyhemoglobin administered intravenously (final plasma concentration 5 x 10(-5) M), pumping was not inhibited. However, the addition of oxyhemoglobin (5 x 10(-5) M) into the reservoir (lumen of the duct) resulted in > 95% inhibition of pumping. The extraluminal administration of oxyhemoglobin (10(-5) M) to bovine mesenteric lymphatics in vitro resulted in a 40% inhibition of pumping, whereas the introduction of oxyhemoglobin (10(-5) M) into the lumen of the vessels suppressed pumping 95%. In vessels mechanically denuded of endothelium, intraluminal oxyhemoglobin inhibited pumping 50%. These results suggested that oxyhemoglobin depressed pumping through an effect on both smooth muscle and endothelium. Once pumping was inhibited with oxyhemoglobin administration, stimulation of the duct with elevations in transmural pressure restored pumping activity when endothelial cells were present. However, in the absence of endothelium, pumping decreased with increases in distending pressures. We conclude that oxyhemoglobin has a direct inhibitory effect on lymphatic smooth muscle. The ability of oxyhemoglobin to alter the pressure range over which the lymph pump operates appears to be dependent on an intact endothelium.

scholarly journals A Novel Method of Measuring Human Lymphatic Pumping in Healthy and Lymphedematous Legs Using Indocyanine Green Fiuorescence Lymphography

2010 ◽  
Vol 51 (3) ◽  
pp. 796-797
Author(s):  
N. Unno ◽  
M. Nishiyama ◽  
M. Suzuki ◽  
N. Yamamoto ◽  
H. Tanaka ◽  
...  
Keyword(s):  
Indocyanine Green ◽  
Novel Method ◽  
Lymphatic Pumping

scholarly journals A novel method of measuring human lymphatic pumping using indocyanine green fluorescence lymphography

2010 ◽  
Vol 52 (4) ◽  
pp. 946-952 ◽  
Author(s):  
Naoki Unno ◽  
Motohiro Nishiyama ◽  
Minoru Suzuki ◽  
Hiroki Tanaka ◽  
Naoto Yamamoto ◽  
...  
Keyword(s):  
Indocyanine Green ◽  
Green Fluorescence ◽  
Indocyanine Green Fluorescence ◽  
Novel Method ◽  
Lymphatic Pumping

scholarly journals Characterization of rat tail lymphatic contractility and biomechanics: incorporating nitric oxide-mediated vasoregulation

2020 ◽  
Vol 17 (170) ◽  
pp. 20200598 ◽  
Author(s):  
Mohammad S. Razavi ◽  
J. Brandon Dixon ◽  
Rudolph L. Gleason
Keyword(s):  
Nitric Oxide ◽  
Mechanical Response ◽  
Contractile Function ◽  
Ex Vivo ◽  
Biomechanical Model ◽  
Biomechanical Models ◽  
Lymphatic Pumping ◽  
Rat Tail ◽  
Lymphatic Contractility

The lymphatic system transports lymph from the interstitial space back to the great veins via a series of orchestrated contractions of chains of lymphangions. Biomechanical models of lymph transport, validated with ex vivo or in vivo experimental results, have proved useful in revealing novel insight into lymphatic pumping; however, a need remains to characterize the contributions of vasoregulatory compounds in these modelling tools. Nitric oxide (NO) is a key mediator of lymphatic pumping. We quantified the active contractile and passive biaxial biomechanical response of rat tail collecting lymphatics and changes in the contractile response to the exogenous NO administration and integrated these findings into a biomechanical model. The passive mechanical response was characterized with a three-fibre family model. Nonlinear regression and non-parametric bootstrapping were used to identify best-fit material parameters to passive cylindrical biaxial mechanical data, assessing uniqueness and parameter confidence intervals; this model yielded a good fit ( R 2 = 0.90). Exogenous delivery of NO via sodium nitroprusside (SNP) elicited a dose-dependent suppression of contractions; the amplitude of contractions decreased by 30% and the contraction frequency decreased by 70%. Contractile function was characterized with a modified Rachev–Hayashi model, introducing a parameter that is related to SNP concentration; the model provided a good fit ( R 2 = 0.89) to changes in contractile responses to varying concentrations of SNP. These results demonstrated the significant role of NO in lymphatic pumping and provide a predictive biomechanical model to integrate the combined effect of mechanical loading and NO on lymphatic contractility and mechanical response.

Inhibition of active lymph pump by simulated microgravity in rats

2006 ◽  
Vol 290 (6) ◽  
pp. H2295-H2308 ◽  
Author(s):  
Anatoliy A. Gashev ◽  
Michael D. Delp ◽  
David C. Zawieja
Keyword(s):  
Thoracic Duct ◽  
Simulated Microgravity ◽  
Fluid Volume ◽  
Tissue Fluid ◽  
Pressure Gradients ◽  
Potent Inhibition ◽  
Detailed Evaluation ◽  
Lymphatic Pumping ◽  
Head Neck ◽  
Normal Head

During spaceflight the normal head-to-foot hydrostatic pressure gradients are eliminated and body fluids shift toward the head, resulting in a diminished fluid volume in the legs and an increased fluid volume in the head, neck, and upper extremities. Lymphatic function is important in the maintenance of normal tissue fluid volume, but it is not clear how microgravity influences lymphatic pumping. We performed a detailed evaluation of the influence of simulated microgravity on lymphatic diameter, wall thickness, elastance, tone, and other measures of phasic contractility in isolated lymphatics. Head-down tail suspension (HDT) rats were used to simulate the effects of microgravity. Animals were exposed to HDT for 2 wk, after which data were collected and compared with the control non-HDT group. Lymphatics from four regional lymphatic beds (thoracic duct, cervical, mesenteric, and femoral lymphatics) were isolated, cannulated, and pressurized. Input and output pressures were adjusted to apply a range of transmural pressures and flows to the lymphatics. Simulated microgravity caused a potent inhibition of pressure/stretch-stimulated pumping in all four groups of lymphatics. The greatest inhibition was found in cervical lymphatics. These findings presumably are correlated to the cephalic fluid shifts that occur in HDT rats as well as those observed during spaceflight. Flow-dependent pump inhibition was increased after HDT, especially in the thoracic duct. Mesenteric lymphatics were less strongly influenced by HDT, which may support the idea that lymph hydrodynamic conditions in the mesenteric lymphatic during HDT are not dramatically altered.

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