Relationship between shape of peripheral initial lymphatics and efficiency of mechanical stimulation–induced lymph formation

Abstract

The functional and morphological features of the peripheral initial lymphatics comprise the mechanical stimulation-dependent lymph formation and irregular shapes of the lumen. A small amount of lymph formation is observed in the tissues of the extremities without mechanical stimulation. However, a skin massage markedly increases lymph formation, even if the massage frequency is an extremely low rate of 0.03 Hz. 1,2 Other mechanical stimulation such as arterial pulse, 3 joint movement, 4,5 and vibration 6 enhances lymph formation in the peripheral tissues. In the skin and subcutaneous tissue, the luminal pressure of the initial lymphatics is higher than that of the interstitial fluid. 7-9 To explain the mechanisms of lymph formation against the pressure gradient, several hypotheses have been proposed to date. 7 In these hypotheses, a two-valve system that comprises an initial lymphatic endothelial microvalve and a collecting lymphatic intraluminal valve is widely accepted as a structure to convert external forces into a one-way flow of fluid from the interstitial space to the lymphatic lumen 10 (Figure 1A). Although the two-valve system theory can explain the mechanisms

Computational fluid dynamic modeling of the lymphatic system: a review of existing models and future directions

“…Next, Ikomi and Hiruma ( 2020 ) investigated the physiological significance of irregular cross-sectional shapes in the initial lymphatics. Their comprehensive study included histological experiments and fluorescence imaging in rats to assess stretch-induced morphological changes.…”

The Microvascular-Lymphatic Interface and Tissue Homeostasis: Critical Questions That Challenge Current Understanding

“…The entry of interstitial fluid into the initial lymphatic network, known as lymph formation, is thought to involve a unique discontinuous junction structure on the lymphatic capillary endothelium commonly referred to as "buttons" [21,22]. Additional factors, such as the irregular shape of lymphatic capillaries, may also contribute, according to results from computational models [23]. Lymphatic capillaries also serve as the main site for entry of antigen-presenting cells and lymphocytes [24][25][26].…”

Biological basis of the aesthetic and rejuvenating effects in the skin after the application of the compressive microvibration Endospheres.

“…The latter seems able to modify the cells of mesenchymal origin underlying the epidermis and their pattern of differentiation/de-differentiation, rejuvenate the tissues, create new adipose tissue, differentiate/de-differentiate resident cells, modulate local staminal cells, and promote angiogenesis (5)(6)(7). All these dynamics are correlated to the fact that the cells of the various tissues, particularly the present staminal cells, react to this particular form of mechanical transduction (1,2,(8)(9)(10). The use of Endospheres to induce effects on tissues and pilot their reaction has already been verified in clinical contexts and appears extremely promising.…”