The Relative Pressures Within Cutaneous Lymphatic Capillaries and the Tissues

Abstract

The formation of lymph takes place in the main through the walls of the minute lymphatic capillaries, the larger channels acting chiefly, if not wholly, as conveyors of this fluid to the blood. To learn something about the forces which tend to promote the formation and flow of lymph in the smallest vessels, the lymph pressure existing within cutaneous lymphatic capillaries in the ears of mice has been compared in the present work with the pressure prevailing in the tissue immediately outside them. This has been done both under normal conditions and during the development of rapidly forming edema which greatly increases lymph formation, as is well known. TechniquesMost of the techniques employed have been those of earlier work in this laboratory (1-5). Improved methods were used for the measurement of edema fluid pressure (5) and for the estimation (4) of the appro~mate pressure in the normal cutaneous tissues, which do not contain enough free fluid for the interstitial fluid pressure to be estimated directly (6-8). Doubtless because of the fact that lymphatic capillaries, unlike blood capillaries, are not readily visible under the microscope, no direct measurements of the lymph pressure in lymphatic capillaries of the skin have been reported previously. However, in the course of other studies (10-15) from this laboratory, the difficulty had been overcome by the development of methods whereby the lymphatic capillaries are rendered visible as they pass through uninjured living skin. As a result, all that was lacking for the study of the pressure relationships inside the lymphatic capillaries and round about them was a suitable method for the measurement of fluid pressure in these channels. The Determination of PressureThe work was carried out on visualized lymphatic capillaries in the skin of the ears of mice lightly anesthetized with nembutal,~0.5 nag. for each 10 gin. of body weight,--as in the previous studies (4). Under these conditions the circulation of the ears appears to be excellent, although the blood pressure is slightly reduced (9).Fine glass tubes were inserted directly into the channels and the capillary pressures were measured manometrically. In the ear of the mouse lymphatic capillaries are larger as a rule than blood capillaries; channels suitable for intubation can be found varying between 25 and 293

Measuring intranodal pressure and lymph viscosity to elucidate mechanisms of arthritic flare and therapeutic outcomes

“…Pressure has been measured in the lymphatic vessels and capillaries in humans, sheep, and rabbits 16–18 . The measurement of lymphatic pressure in small mammals is scarce, but an early study measured pressure of lymphatic vessels in mouse ear 19 . However, there is no report of measuring lymphatic pressure in draining lymph nodes of mouse limbs where arthritis occurs.…”

Structure and Function of Lymphatic Vessels of the Bat's Wing

“…This transfer of the fluid occurs because the hydrostatic pressure is higher in the tissues than in the lymphatics. McMaster [1947] reported a pressure head of 07 cm of H20 in normal conditions in skin interstitial space rising to the order of 6-0 cm of H20 in oedema. The existence of a positive interstitial pressure under normal states has been challenged by Guyton [1963,1965] and independently by Scholander et al [1968].…”

“…One is to be able to collect fluid from the tissues, and the other is to move the fluid away from the site of collection and back, generally via the thoracic duct, into the circulating blood stream. Valuable information has been obtained from in vivo observations of lymphatic function in the amphibian tail [Clark, 1912;Clark and Clark, 1920], in the rabbit ear chamber [Clark and Clark, 1932, 1933, 1937, in rat mesentery [Webb, 1933], in the mouse ear [McMaster, 1947;Pullinger and Florey, 1935], in a variety of acute dissected preparations in mammals [Florey, 1927;Pullinger and Florey, 1935;Smith, 1949] and in the membrane of the bat's wing [Webb and Nicoll, 1944]. There has not been any direct extension of in vivo observations such as these so as to correlate observed physiological function with ultrastructural morphology on the identical vessel.…”

Progress toward resolving the controversy of positive Vs. negative interstitial fluid pressure.

“…However, Chambers and Zweifach (1947) have shown that hyaluronidase disrupts capillary membrane integrity so that the tissue hydrostatic pressures would be abnormally high after treatment with hyaluronidase. In fact, McMaster (1947) showed that hyaluronidase increased edema fluid pressure by approximately 5 mm Hg. Thus, the effects of hyaluronidase on the negative capsular pressure do not necessarily mean that the negative pressure is an artifact.…”

“…Calculated from Starling equation P j -1. Isogravimetric P c (Pappenheimer and Soto-Rivera, 1948) 2 Micropuncture P r (Hargens et al, 1978b) B Lymphatic pressure 1 Pressure in initial lymphatics (McMaster, 1947) fluid pressure and total pressure within the interstitial spaces. As McDonald (1968) pointed out, the pressure beneath normal skin exposed to atmospheric pressure must be essentially atmospheric, i.e., zero.…”