In vivo microscopy of hepatic tumors in animal models: a dynamic investigation of blood supply to hepatic metastases.

Abstract

The dynamics of blood circulation in three experimental animal models of hepatic metastasis were investigated with in vivo microscopy. It was demonstrated that the tumor vasculature communicated with the portal venules and hepatic sinusoids that surrounded the tumors. The hepatic artery was not seen to connect to the tumors directly. However, it was demonstrated that arterial blood entered tumors through the portal venules and that the hepatic arterial flow entered the tumor without resistance, while blood from the portal vein met great resistance at the tumor border, with only small amounts entering the tumor. Interruption of either the hepatic artery or the portal vein did not result in cessation of the blood circulation in hepatic tumors. A reciprocal relationship between the hepatic arterial and portal venous supplies to hepatic tumors was suggested, and it was hypothesized that arterioportal communications play an important role in the arterial and portal venous supply of blood to hepatic tumors. A comprehensive understanding of the blood supply of hepatic tumors is important for improving clinical treatment of hepatic tumors.

Perfusion CT Assessment of Tissue Hemodynamics Following Hepatic Arterial Infusion of Increasing Doses of Angiotensin II in a Rabbit Liver Tumor Model

“…Since the blood vessels in hepatic tumors, including VX2 cancers, commonly lack smooth muscle ( 20,21 ), the arterial infusion of vasoconstricting agents should constrict vessels in the normal liver while leaving the tumor vessels unaffected. This shunts blood from the normal liver parenchyma to the tumor, resulting in increased tumor exposure to transarterially administered therapeutic agents because hepatic tumors derive approximately 90% of their blood supply from the hepatic artery, unlike normal liver tissue, which receives 70%-80% of its blood supply from the portal vein (22)(23)(24). Angiotensin II is a potent vasoconstrictor that has been shown to enhance the liver tumor-normal liver tissue BF ratio ( 3,4,6 ) and reduce the common hepatic arterial BF ( 5 ) after its hepatic arterial administration in patients with primary and metastatic liver tumors.…”

Development of Arterial Blood Supply in Experimental Liver Metastases

“…1 Since then numerous papers have been published using human and experimental materials and different methods such as corrosion casting, confocal and electron microscopy, angiography, radiolabeled microspheres, and in vivo microscopy, have been used to study the blood supply of liver metastases. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] A large proportion of these articles have confirmed the original observation of Breedis and Young, 1 but no mechanism for the development of the arterial blood supply in metastases has ever been presented. [2][3][4][5][6][7] On the other hand, numerous papers, including ours, have emphasized the contribution of the portal vein, either directly or through the sinusoids in the blood supply of hepatic metastases.…”

“…According to the observations of Yamamoto et al 15 there are extensive arterioportal anastomoses throughout the vascular tree in rats, whereas a separate arterial and portal tree, without direct arterioportal communication, can be observed in hamster and human liver. Opinions about the presence of arterioportal anastomoses in mice are controversial 10,16 ; therefore, we have addressed this question first.…”

Mutant Bik expression mediated by the enhanced minimal topoisomerase IIα promoter selectively suppressed breast tumors in an animal model

“…[47][48][49] Increased permeability would facilitate movement of liposome complex from vessels into tumor interstitium. Actually, it has been reported that cationic liposome complex is preferentially accumulated in tissues with high density of capillaries (e.g.…”