Partial heterotopic liver homograft in dogs utilizing portal arterialization

Effect of portocaval shunt on residual extreme small liver after extended hepatectomy in porcine

BACKGROUND

When residual liver volume is extremely small after extended hepatectomy, postoperative hepatic failure may ensue. The cause of the hepatic failure is likely associated with the portal hypertension after hepatectomy. We investigated the effects of portocaval shunt on portal hypertension in producing sinusoidal microcirculatory injury after extended hepatectomy in pigs.

METHODS

Fourteen pigs were divided into two groups: a group without a shunt, in which extended hepatectomy was carried out (i.e., residual volume was 17% of the whole liver), and a group with a shunt, in which extended hepatectomy was carried out and a portocaval shunt was inserted. The portocaval shunt was placed by side-to-side anastomosis between the portal vein and the inferior vena cava.

RESULTS

In the group without a shunt, all pigs died of hepatic failure within postoperative day 3. In the group with a shunt, all pigs were alive for more than 4 days, and 4 pigs survived longer than 7 days. Portal vein pressure after hepatectomy was 15.9 +/- 3.8 mmHg in the group without a shunt and 10.5 +/- 0.6 mmHg in the group with a shunt (P < 0.01). The portal vein flow after 83% hepatectomy in the group without a shunt increased significantly more than at laparotomy and in the group with a shunt (P < 0.01). In the group without a shunt, remarkable destruction of the sinusoidal lining and edema of the portal triad and hydropic change of hepatocytes were observed 1 hour after hepatectomy, but these findings were not observed in the group with a shunt.

CONCLUSIONS

These results indicate that, after extended hepatectomy, overload of portal flow is one of the most significant risk factors of hepatic failure by sinusoidal microcirculatory injury.

Effect of portocaval shunt on residual extreme small liver after extended hepatectomy in porcine

BACKGROUND

When residual liver volume is extremely small after extended hepatectomy, postoperative hepatic failure may ensue. The cause of the hepatic failure is likely associated with the portal hypertension after hepatectomy. We investigated the effects of portocaval shunt on portal hypertension in producing sinusoidal microcirculatory injury after extended hepatectomy in pigs.

METHODS

Fourteen pigs were divided into two groups: a group without a shunt, in which extended hepatectomy was carried out (i.e., residual volume was 17% of the whole liver), and a group with a shunt, in which extended hepatectomy was carried out and a portocaval shunt was inserted. The portocaval shunt was placed by side-to-side anastomosis between the portal vein and the inferior vena cava.

RESULTS

In the group without a shunt, all pigs died of hepatic failure within postoperative day 3. In the group with a shunt, all pigs were alive for more than 4 days, and 4 pigs survived longer than 7 days. Portal vein pressure after hepatectomy was 15.9 +/- 3.8 mmHg in the group without a shunt and 10.5 +/- 0.6 mmHg in the group with a shunt (P < 0.01). The portal vein flow after 83% hepatectomy in the group without a shunt increased significantly more than at laparotomy and in the group with a shunt (P < 0.01). In the group without a shunt, remarkable destruction of the sinusoidal lining and edema of the portal triad and hydropic change of hepatocytes were observed 1 hour after hepatectomy, but these findings were not observed in the group with a shunt.

CONCLUSIONS

These results indicate that, after extended hepatectomy, overload of portal flow is one of the most significant risk factors of hepatic failure by sinusoidal microcirculatory injury.

Effect of portocaval shunt on residual extreme small liver after extended hepatectomy in porcine

BACKGROUND

When residual liver volume is extremely small after extended hepatectomy, postoperative hepatic failure may ensue. The cause of the hepatic failure is likely associated with the portal hypertension after hepatectomy. We investigated the effects of portocaval shunt on portal hypertension in producing sinusoidal microcirculatory injury after extended hepatectomy in pigs.

METHODS

Fourteen pigs were divided into two groups: a group without a shunt, in which extended hepatectomy was carried out (i.e., residual volume was 17% of the whole liver), and a group with a shunt, in which extended hepatectomy was carried out and a portocaval shunt was inserted. The portocaval shunt was placed by side-to-side anastomosis between the portal vein and the inferior vena cava.

RESULTS

In the group without a shunt, all pigs died of hepatic failure within postoperative day 3. In the group with a shunt, all pigs were alive for more than 4 days, and 4 pigs survived longer than 7 days. Portal vein pressure after hepatectomy was 15.9 +/- 3.8 mmHg in the group without a shunt and 10.5 +/- 0.6 mmHg in the group with a shunt (P < 0.01). The portal vein flow after 83% hepatectomy in the group without a shunt increased significantly more than at laparotomy and in the group with a shunt (P < 0.01). In the group without a shunt, remarkable destruction of the sinusoidal lining and edema of the portal triad and hydropic change of hepatocytes were observed 1 hour after hepatectomy, but these findings were not observed in the group with a shunt.

CONCLUSIONS

These results indicate that, after extended hepatectomy, overload of portal flow is one of the most significant risk factors of hepatic failure by sinusoidal microcirculatory injury.

Role of shear stress and immune responses in liver regeneration after a partial hepatectomy

This report reviews studies addressing the new concepts in liver regeneration after a partial hepatectomy (PHx). The review begins with an overview of the immunologic mechanisms of liver regeneration after PHx, especially regarding Kupffer cells and extrathymic T cells of the regenerative liver in the cell-mediated immunity, based on major histocompatibility complex I and II antigens. Attention is then devoted to "on and off" studies in liver regeneration after PHx, by hypothesizing the shear stress based on the fact that the portal flow against hepatocytes or sinusoidal endothelial cells triggers their regeneration after a partial hepatectomy and controls the volume of the regenerating liver by the stimulating the cell surface modulator (CSM) of hepatocytes and sinusoidal endothelial cells (SEC). We propose that the acute elevation of shear stress after PHx influences the adhesion between SEC and intrahepatic leukocytes. These concepts are expected to positively contribute to the future research on liver regeneration after PHx.

Short-term effect of portal vein arterialization on hepatic protein synthesis and endotoxaemia after extended hepatectomy in dogs

To assess the effect of partial portal arterialization on the remaining liver after usually lethal extended hepatectomy, 30 mongrel dogs underwent 84% partial hepatectomy and were divided into three groups as follows: group 1, 84% partial hepatectomy (n = 10); group 2, 84% partial hepatectomy and splenectomy (n = 10); group 3, 84% partial hepatectomy and splenectomy and splenic artery-vein (A-V) shunt (n = 10). Another five dogs were pre-operatively killed normal controls. Portal vein flow (PVF) decreased to about 60% in groups 1 and 2, but PVF in group 3 was maintained at the pre-operative level. Oxygen saturation of portal vein blood increased markedly, to between 83% (group 1) and 88% (group 3). Portal vein pressure (PVP) increased in groups 1 and 2 by 1.6 to 1.7 times the pre-operative value, but no significant difference in PVP, serum aspartate aminotransferase (AST) and arterial ketone body ratio was found between the three groups. Plasma endotoxin levels after 84% partial hepatectomy were significantly lower in group 3 than in groups 1 and 2. Both of hepatocellular and secretory protein synthesis were enhanced in group 3 compared with the other two groups. These results suggest that partial portal arterialization using a splenic A-V shunt might bring about a beneficial effect on remaining liver function after extended hepatectomy.

Effect of prior portosystemic shunt on early hepatic hemodynamics and sinusoids following 84% hepatectomy in dogs

The effects of a prior portosystemic shunt (PSS) on the hepatic hemodynamics and sinusoids shortly after an 84% hepatectomy (Hx) were investigated in dogs. Fifteen mongrel dogs were divided into three groups, a 70% Hx group (n = 5), an 84% Hx group (n = 5) and an 84% Hx+PSS group (n = 5). In the last group, a shunt was inserted between the splenic and femoral veins prior to the hepatectomy. The systemic and hepatic hemodynamics were measured, before and 180 min after the hepatectomy, and the remaining liver tissue was then examined immunohistochemically by light microscopy using the thrombomodulin (TM) staining method. The postoperative portal vein pressure and the vascular resistance were significantly lower in the PSS group than in the 84% non-PSS group. The total postoperative hepatic blood flow was higher in the 84% non-PSS group than in the other two groups. Immunohistochemical observation after TM staining indicated that the sinusoidal endothelial cells in the 84% non-PSS group were markedly damaged 3 h after surgery. We conclude that a prior PSS improves the hepatic hemodynamics and is beneficial to the sinusoids within the first few hours of an 84% hepatectomy in dogs.