Use of von Willebrand diseased kidney as donor in a pig-to-primate model of xenotransplantation.

BACKGROUND: The coagulation process in hyperacute and delayed xenograft rejection is essential and depends upon platelet adhesion and aggregation. The initial binding of platelets to the damaged endothelium is due to the interaction of the platelet receptor glycoprotein Ib with von Willebrand factor (vWF), which is present on activated endothelial cells and bound to the subendothelial matrix. We hypothesized that the use of organs from animals with homozygous von Willebrand disease (vWD), severely deficient in vWF, might prevent the thrombosis encountered in delayed xenograft rejection. METHODS: Ten baboons were treated by extracorporeal immunoadsorption of xenoreactive natural antibodies (XNA) through the donor pig liver to inhibit hyperacute rejection and received heterotopic vWD or control pig kidney xenografts. XNA levels, coagulation, and platelet activation markers were studied, and specimens of rejected kidneys were analyzed histologically. RESULTS: Although XNA depletion was comparable in both groups, neither kidney function nor survival times of control (n=5) or vWD (n=5) porcine kidneys showed any difference. Platelet and coagulation activation was evidenced in both groups after surgery and at rejection time. Immunohistochemical analysis revealed a weak endothelial vWF immunostaining in the rejected vWD kidneys, whereas it was undetectable in the nongrafted vWD kidneys, suggesting the deposition of baboon plasma vWF on the porcine vessels. CONCLUSIONS: The use of vWD organs did not improve the survival time of grafted kidneys in this xenotransplantation model. Further studies on the use of vWD organs, in association with other therapeutic approaches, such as complement inhibition, are nevertheless necessary to evaluate the usefulness of vWF deficiency as an adjunctive therapy to decrease the coagulation process during xenograft rejection.

Hematologic and plasma biochemical values for Tonkean macaques (Macaca tonkeana).

Hematologic and serum biochemical parameters were measured in 29 captive Tonkean macaques (Macaca tonkeana) to provide normative reference values for the species. Mean normal values and ranges were close to those reported in other species of macaques. Some significant variations related to age and sex were found.

Protective effects of N-acetylcysteine on hypothermic ischemia-reperfusion injury of rat liver.

We investigated whether intraportal injection of 150 mg/kg N-acetylcysteine (NAC) into rats reduced hepatic ischemia-reperfusion injury after 48 hours of cold storage and 2 hours of reperfusion. The organ was isolated and perfused to evaluate liver function. The control group received an intraportal injection of 5% dextrose. NAC increased L-cysteine concentrations 15 minutes after injection (1.29 +/- 0.11 mumol/g vs. 2.68 +/- 0.4 mumol/g, P < .05). However, neither treatment modified glutathione liver concentrations relative to preinjection values. After 48 hours of cold storage and 2 hours of reperfusion, livers from NAC-treated rats produced larger amounts of bile than those in the control group (5.04 +/- 1.92 vs. 0.72 +/- 0.37 microL/g liver; P < .05), and showed a significant reduction in liver injury, as indicated by reduced release of lactate dehydrogenase (679.4 +/- 174.4 vs. 1891.3 +/- 268.3 IU/L/g; P < .01), aspartate transaminase (AST) (13.94 +/- 3.5 vs. 38.75 IU/L/g; P < .01), alanine transaminase ALT) (14.92 +/- 4.09 vs. 45.91 +/- 10.58 IU/L/g; P < .05), and acid phosphatase, a marker of Kupffer cell injury (344.4 +/- 89.6 vs. 927.3 +/- 150.8 IU/L/g; P < .01) in the perfusate. Reduced glutathione concentrations in the perfusate were similar in the two groups (805 +/- 69 vs. 798 +/- 252 nmol/L/g), whereas oxidized glutathione (GSSG) concentrations were higher in the control group (967 +/- 137 vs. 525 +/- 126 nmol/L/g; P < .05). Reduced glutathione (GSH) concentrations in liver tissue collected at the end of perfusion were significantly higher in the NAC group (7.3 +/- 0.9 vs. 4.1 +/- 1.0 mumol/g; P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Amelioration of hepatocellular integrity and inhibition of sinusoidal oxidative stress by N-acetylcysteine pretreatment in cold ischemia-reperfusion injury of rat liver.

Further improvements of donor liver preservation are still required in liver transplantation. In the present study, we investigated whether intraportal injection of N-acetylcysteine (NAC) 15 min before flush-out of UW solution (NAC pretreatment) improves liver dysfunction after cold preservation or has a protective effect on sinusoidal oxidative stress. The effect of NAC pretreatment was examined using an isolated perfused rat liver model. The NAC pretreatment significantly reduced sinusoidal oxidative stress relative to a control dextrose 5% injection. Under a glutathione-depleted condition produced by L-buthionine-[S-R]-sulfoximine, the NAC pretreatment also significantly reduced hepatocellular as well as sinusoidal oxidative stress, resulting in improvement of hepatocelllar integrity relative to a control dextrose 5% injection.