Flow velocity of single lymphatic capillaries in human skin

Abstract

The purpose of this study was to investigate the previously unknown flow velocity in single lymphatic capillaries of humans in the supine position. Fifteen healthy subjects (10 women and 5 men; mean age 35.8 +/- 13.1 yr) were studied. Ten microliters of fluorescein isothiocyanate-dextran (150,000 mol wt) were injected into the subepidermal layer of the foot dorsum. The filling of the microlymphatics from the resulting depot was visualized by fluorescence video microscopy and stored on videotape. Flow velocity in the microlymphatics was determined on the video screen by direct measurement of the advancement of dyed lymph during a given time. The following median velocities were obtained: 0.51 mm/s (0.27 and 0.61 mm/s for lower and upper quartiles, respectively) for velocity during initial network filling and 9.7 microns/s (6.9 and 14.2 microns/s for lower and upper quartiles, respectively) for resting velocity at the end of the filling period. Mean lymphatic capillary diameter was 54.8 +/- 8.2 microns, and mean network extension was 8.3 +/- 3.2 mm. The high filling velocities are probably due to increased interstitial pressure and volume caused by dye microinjection, whereas the values measured during the end of network filling seem to approach resting flow velocities.

In vivo label-free lymphangiography of cutaneous lymphatic vessels in human burn scars using optical coherence tomography

“…The resulting lymphatic vessel images enable the visualization of the individual vessels with diameters of ~30-150 µm and the interconnection of the vessels to form a network. Previous studies have reported the diameters of the cutaneous lymphatic capillaries (37-76 µm) [28,29], which are broadly in agreement with our results. We hypothesize that the larger vessels identified in our images may be dilated in response to inflammation [1] attributed to the wound healing process [30].…”

Laminar flow downregulates Notch activity to promote lymphatic sprouting

“…On the other hand, shear force levels in other postnatal lymphatics have been previously estimated. Under a basal physiological condition, the shear force level was approximately 0.64 dyn/cm 2 in a collecting lymphatic vessel (45), 0.001 dyn/cm 2 in mouse tail capillaries (46), and 0.003 dyn/cm 2 in human skin capillaries (47). Compared with these very low shear force levels, however, conceptual predicnology (43) and studied the impact of genetic ablation of Dtx3l on embryonic lymphatic development.…”

Rapid Transepithelial Transport of Prions following Inhalation

“…It is not likely that the persistence of brain homogenate in the lymphatics is simply due to a low rate of lymph flow in the nasal cavity, given that flow rates have been reported to average 3 to 9 m/s in different species (5,23,82) and that dye placed in the nose reaches cervical lymph nodes in 14 to 51 min, depending on the species (88). The presence of brain homogenate within lymphatics is consistent with their role of draining fluid and macromolecules from the extracellular matrix of the lamina propria in the nasal cavity.…”