Origins and pathways of fluid entering sublobular lymphatic vessels in cat livers

Abstract

The liver, which produces a large volume of lymph, has a lymphatic system which can be classified into three categories: portal, sublobular, and superficial lymphatic vessels. As little is known about the origin and pathways of sublobular lymph, this study demonstrates pathways of interstitial fluid flowing into sublobular lymphatic vessels. Livers from cats whose thoracic ducts were either ligated or non-ligated were examined by light-, transmission electron- and scanning electron-microscopy (SEM). Complete ligation of the thoracic duct caused significant dilation of the hepatic sinusoids, the space of Disse, and channels passing through the limiting plate. Sublobular interstitial space and sublobular lymphatic vessels were also expanded. The channels between hepatocytes forming the limiting plate contained collagen fibers, and connected the space of Disse with a sublobular interstitial space. The alkali-water maceration/SEM confirmed that collagen fibers traversing the layer of the limiting plate independently of blood vessels connected collagen fibers in the space of Disse with those in the sublobular space. Complete ligation of the thoracic duct also showed an accumulation of mast cells and plasma cells in the sublobular interstitial space. Our data suggest that fluid in the space of Disse flows along collagen fibers in channels traversing the limiting plate as well as those along the sinusoids and central veins that drain into sublobular veins, and enters the sublobular interstitial space to finally lead into sublobular lymphatic vessels. Our study has also shown that hepatic lymphostasis causes the accumulation of mast cells and plasma cells in the sublobular interstitial space, which may be involved in lymphangiogenesis and fibrogenesis.

Lymphatic Vessel Network Structure and Physiology

“…13)(428, 794, 800). Similar pathways between hepatocytes allow interstitial fluid to enter the perihepatic interstitial tissue to enter sublobular and superficial lymphatic networks (868). For the superficial lymphatics, the deepest superficial lymphatic plexus represents the initial lymphatics that serve as the site of lymph formation, with a middle precollector layer, and an outer capsular layer of collecting lymphatics.…”

Collagen arrangement in space of Disse correlates with fluid flow in normal and cirrhotic rat livers

“…In normal rat liver, the portally directed lymph flow uses channels that traverse the limiting plate before entering the interstitial space of the portal tracts, and finally move from the prelymphatic vessels to the portal lymphatic vessels (Ohtani et al, ). In the thoracic duct‐ligated liver of cats, the lymph vessels in the walls of the tributaries of the hepatic veins become more important and increase in diameter (Poonkhum et al, ). This lymph flow was visualized with intravenously injected HRP (Ohtani et al, ), which has a strong affinity for collagen fibers (Fan, ).…”

“Frontiers in Fontan failure: A summary of conference proceedings”

“…After Fontan palliation, the liver is exposed to elevated, nonpulsatile systemic venous pressure and diminished cardiac output. The lymphatics are also affected, with lymphostasis combining with elevated venous pressure to form a “double hit” to the patient . Normally, the liver receives 70% of its inflow from the portal vein and the remainder from the hepatic artery.…”