Dependence of platelet function on underlying liver disease in orthotopic liver transplantation.

OBJECTIVE: The purpose of the present study was to explore the platelet function during the perioperative period of orthotopic liver transplantation (OLT) due to the underlying liver disease. METHODS: The blood coagulation parameters, platelet surface markers and the determination of platelet aggregation were analyzed in 34 patients who underwent OLT. Blood samples were drawn preoperatively, anhepatic, 10 min and 1 hour after reperfusion, 1 day, 3 and 7 days postoperatively. Conventional coagulation screens, thrombopoietin (TPO) serum levels, P-selectin, GPIIb/IIIa and GPIb binding sites on the surface of platelets as evaluated by flow cytometry and platelet aggregation response were measured. RESULTS: Coagulation factors, maximum aggregation and rate of aggregation were significantly different before transplantation due to the underlying liver disease. Further we found a markedly depressed GPIIb/IIIa and P-selectin expression and a reduced rate of aggregation in all patients throughout the study. In contrast maximum aggregation of platelets was restored on the third day after reperfusion without intergroup differences and almost comparable to healthy controls. An inverse correlation was found between peripheral platelet count pre-transplantation and peak TPO concentrations one weak post-transplantation. CONCLUSIONS: In the entire process of OLT, coagulation factors, maximum aggregation and rate of platelet aggregation depend on the surgical phases during transplantation and on the underlying liver disease. The data obtained in this study might contribute to a better understanding of the pathophysiology and assessment of bleeding risk in OLT.

The role of portal vein clamping for cytokine release and neutrophils activity during liver resection and transplant.

OBJECTIVES: Uncontrolled release of cytokines has been linked to graft dysfunction or rejection and contributes to an increase in mortality and morbidity. We argue that temporary vascular clamping of the hepatic pedicle during major hepatic surgery is a potential stimulus for an excessive release of cytokines and the activity of neutrophils. MATERIALS AND METHODS: Thirty patients underwent partial liver resection or transplant. Samples were drawn preoperatively, immediately before portal vein clamping, at the early reperfusion period, and on days 1, 3, 5, and 7 after the operation. Central venous plasma concentrations of IL-6, IL-8, and TNF- a were compared to portal venous plasma. The influence of neutrophils on metabolic activity was measured by flow cytometry. RESULTS: In both patient groups, no significant differences in cytokine concentrations between central and portal venous plasma were found. However, significant differences of neutrophils activity were observed in patients undergoing partial liver resection compared to patients after transplant. CONCLUSION: Portal vein stasis induced by clamping the hepatic pedicle has no influence on the local release of IL-6, IL-8, and TNF-a. However, preoperatively increased plasma levels of TNF-a play a decisive role in the metabolic activity of neutrophils in patients with final-stage liver disease.

In situ-RT-PCR and immunohistochemistry for the localisation of the mRNA of the alpha 3 chain of laminin and laminin-5 during human organogenesis.

Laminin-5 is known to be an integral part of the hemidesmosome and therefore responsible for the integrity of the connection of the epithelium to the basement membrane. This is also an important mechanism during embryonic development, as documented by studies in mice. In an attempt to elucidate its implication for human development we localised the mRNA of the alpha3 chain of laminin with the help of in situ RT-PCR, and the laminin-5 protein immunohistochemically. We systematically investigated kidney, lung, skin and intestinal tissue of consecutive developmental stages during human embryogenesis. From gw 6.5 onwards, the mRNA of the alpha3 chain of laminin was found exclusively in the cytoplasm of epithelial cells of the developing kidney, lung, skin and intestine. Interestingly, in the skin and intestine from gw 8 onwards, the superficial cell layers also stained positive for the mRNA, while the protein was still only found in the dermal-epidermal and enteric basement membrane zones. In all developing organs investigated, the mRNA of the alpha3 chain of laminin is strictly of epithelial origin and the corresponding protein localised in the underlying basement membrane zones. Due to this discrepancy, we postulate a broader role for laminin-5 during human embryogenesis, for example, for epithelial cell development, beyond its involvement in hemidesmosome formation and cell adhesion.