Biomechanical study of hepatic portal vein in humans and pigs and its value in liver transplantation.

OBJECTIVE: Our aim was to explore the biomechanical properties of hepatic portal vein (HPV) in humans and pigs to provide evidence for liver xenotransplantation. MATERIALS AND METHODS: The pressure-diameter relationships of HPV from 6 deceased donors and 36 pigs were measured on a biomechanical experimental stand to calculate the elastic modulus and compliance. Each sample sliced into 5-mm frozen sections was stained with hematoxylin-eosin (H&E). Geometric morphological indices were measured with a computer image analysis system. RESULTS: The length, wall thickness, and diameters of HPV in pigs increased from 1 to 6 months (P < .05). There were no significant differences between 6-month-old pigs and adult humans (P > .05). The incremental elastic modulus of the pig HPV increased with age, whereas the compliance decreased. There was no difference in the elastic modulus of HPV between 5- to 6-month-old pigs and humans (P > .05). Also, there was no difference in HPV compliance between 6-month-old pigs and humans (P > .05). CONCLUSIONS: Our results suggested that the biomechanical properties of HPV in 6-month-old pigs were similar to those of humans. From a biomechanical perspective, anastomosis of corresponding HPV from 6-month-old pigs to humans may be feasible in the process of pig-to-human liver xenotransplantation.

Up-regulation of Twist induces angiogenesis and correlates with metastasis in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a highly invasive tumor characterized by vigorous neovascularization. The purpose of this study is to examine the expression of Twist, a highly conserved bHLH transcription factor that is known to promote EMT, and evaluate its effect on tumor angiogenesis and metastasis of HCC. The mRNA expression of Twist, VEGF, E-cadherin, and N-cadherin was determined by Real-Time RT-PCR in 30 pairs of hepatocellular carcinomas and matched non-cancerous tissues. Immunohistochemistry was carried out to analyze the protein expression of Twist, VEGF, E-cadherin, and N-cadherin in 40 hepatocellular carcinoma cases. The staining of endothelial cells for CD34 was used to evaluate the MVD. We found that Twist mRNA and protein were both increased in HCC as compared to non-cancerous tissues. The HCC specimens showing positive Twist expression had a higher microvessel density than those without Twist expression. And up-regulated Twist protein was significantly associated with intrahepatic and extrahepatic metastasis (p=0.048 and P=0.039 respectively). In addition, patients with Twist expression had poor prognosis. We also found that the expression of Twist positively correlated with up-regulation of VEGF and N-cadherin (P=0.002 and p=0.016 respectively), but not with downregulation of E-cadherin in HCC. Our results demonstrate that Twist may play an important role in the angiogenesis and metastasis of HCC. Twist expression may become a potential novel prognostic factor for the disease survival of HCC.