Successful ABO-incompatible liver transplantation using A2 donors.

INTRODUCTION: The longer waiting time for a liver graft among patients with blood group O makes it necessary to expand the donor pool for these patients. We herein have reported our experience with ABO-incompatible liver transplantation using A(2) donors to blood group O recipients. PATIENTS AND METHODS: Between 1996 to 2005, 10 adult blood group O recipients received 10 A(2) cadaveric grafts. Mean recipient age was 52 +/- 7.7 years (mean +/- SD). The initial immunosuppression was induction with antithymocyte globulin (n = 2), interleukin-2-receptor antagonists (n = 3), or anti-CD20 antibody (rituximab, n = 1), followed by a tacrolimus-based protocol. No preoperative plasmapheresis, immunoadsorption, or splenectomies were performed. RESULTS: Patient and graft survival was 10/10 and 8/10, respectively, at 8.5 months median follow-up (range 10 days to 109 months). Two patients were retransplanted because of bacterial arteritis (n = 1) and portal vein thrombosis (n = 1). The six acute rejections, which occurred in four patients, were all reversed by steroids or increased tacrolimus dosages. The pretransplant anti-A titers against A(1) red blood cells were 1:128 (NaCl technique) and 1:8 to 1024 (IAT technique). The maximum postoperative titers were 1:64 to 4000 (NaCl) and 1:256 to 32000 (IAT). CONCLUSION: The favorable outcome of A(2) to O grafting, with a patient survival of 10/10 and graft survival of 8/10, makes it possible to consider this blood group combination also in nonurgent situations. There was no hyperacute rejection or increased rate of rejections. Anti-A/B titer changes seem to not play a significant role in the monitoring of A(2) to O liver transplantation.

Ischemic preconditioning can overcome the effect of moderate to severe cold ischemia on concordant mouse xeno-heart transplants.

PURPOSE: Concordant mouse xeno-heart transplants are relatively sensitive to ischemia-reperfusion injury. We investigated the effect of an ischemic preconditioning (IPC) protocol on the functional and biochemical outcome of mouse xenohearts transplanted to the Lewis rat. MATERIAL AND METHODS: NMRI mice (30 to 40 g) were anesthetized, intubated, and mechanically ventilated. They were subjected either to a IPC protocol leading to an SaO(2) of 70% for 5 minutes followed by normoxia (defined as SaO(2) >90%) for 10 minutes (n = 9) or normoxia only (n = 11). The hearts were then heterotopically transplanted to Lewis rats (220 g). The frequencies of immediate onset and early dysfunction and late dysfunction were registered. The hearts surviving for 6 hours were explanted and the absolute concentrations of phosphocreatine and adenosine triphosphate (ATP) were determined in micromole per gram of heart tissue with high-pressure liquid chromatography. The phosphorylation ratio, PCr/ATP, a known correlate to biochemical and functional outcome, was calculated. RESULTS: Four of 11 (36.4%) of control hearts experienced immediate onset and early dysfunction versus 0% (0/9) in M hearts subjected to IPC (P = .01). Furthermore, the IPC protocol increased the PCr concentration, 15.08 +/- 1.00 versus 9.04 +/- 2.04 micromol/g in controls (P = .01), and the PCr/ATP ratio, 1.80 +/- 0.17 versus 1.27 +/- 0.21 (NS; P = .06). CONCLUSIONS: IPC provides a protective PCr overshoot overcoming the short-term effects of moderate to severe ischemic injury on mouse xeno-heart transplants.

Singlet oxygen energy illumination during moderate cold ischemia prolongs the survival of concordant hamster xeno-heart transplants.

INTRODUCTION: Singlet oxygen energy (SOE) is a potent inhibitor of reactive oxygen species (ROS) in vitro and in vivo in certain dose ranges and can improve the levels of high-energy phosphates (HEP) in concordant hamster xeno-heart transplants. Some data indicate that a certain degree of cold ischemia (CI) might be beneficial to xenotransplants. We investigated if SOE illumination of hamster xeno-hearts during moderate cold ischemia (CI) improved graft survival. MATERIALS AND METHODS: Eighteen hearts from Golden Syrian hamsters (70 to 80 g) were subjected to 8 hours of CI in cold (+4 degrees C) saline solution (NaCL, 0.9%) before heterotopic cervical transplantation to Lewis rats (220 g). Among the treatment group (n = 8), SOE was produced by illuminating the hearts for 10 minutes every 30 minutes with photons at lambda 634 nm with the Oxylight equipment. Graft function was evaluated every 6 hours after transplantation with digital exam until cessation of heart beats. RESULTS: The graft survival of SOE-illuminated ischemic hamster xenografts was 2.34 +/- 0.56 versus 1.15 +/- 0.37 days in the control group (P < .05). All hearts displayed immediate graft function versus 70% in the controls (NS). CONCLUSIONS: SOE illumination at lambda 634 nm during moderate cold ischemia (+4 degrees C) can improve the survival of concordant hamster xeno-heart transplants. The exact mechanism(s) are currently unknown, but the effect might in part be exerted by a combination of reduced production of ROS and increased oxidative phosphorylation.

Determination of enantiomer separation factors by nuclear magnetic resonance spectroscopy and by chiral liquid chromatography.

The equilibrium constants K+ and K- for formation of the diastereomeric complexes of the two enantiomers of O,O'-dibenzoyltartaric acid (DBTA) with the chiral selector N,N'-diallyltartardiamide bis-(4-tert.-butylbenzoate) (TBB) have been determined by 1H-NMR. The experiments were performed at different temperatures in CDCl3 or in cyclohexane-d12/2-propanol-d8 mixtures. The equilibrium constants from the 1H-NMR results have been compared with the retention factors (k') obtained from the chromatographic resolution of rac. DBTA on a Kromasil CHI-TBB column with the same solvents as mobile phases. A satisfactory correlation between the 1H-NMR data and the chromatographic data was found.

Solvent-dependent enantioselective interaction of some bis-allylamide chiral selectors studied by NMR.

A series of chiral selectors, all of them bis-allylamides of C(2)-symmetric dicarboxylic acids, were studied by NMR in different solvents in an attempt to affect the equilibria between free selector and the diastereomeric complexes formed by its interaction with the (+)- and (-)-forms of O,O'-dibenzoyltartaric acid (DBTA). The results show that by changing the polarity of the solvent the equilibria are displaced, as observed from changing chemical shift differences. Phase-sensitive (1)H[(1)H]-NOESY experiments revealed different interactions between the chiral selector and the analyte enantiomers. The individual equilibrium constants were determined by separate studies of the equilibria between the selector and the respective enantiomers of the chiral DBTA probe.

A new chiral selector based on trans-acenaphthen-1,2-dicarboxylic acid.

The chiral selectors (R,R)- and (S,S)-trans-acenaphthen-1,2-dicarboxylic acid bis-allylamide have been synthesized and characterized. The route to the selectors involved synthesis of the trans-dicarboxylic acid via sodiation and carbonation of acenaphthylene, followed by reaction of the bis-acid chloride with allylamine. The racemic bis-allylamide derivative was resolved into its enantiomers by preparative liquid chromatography. The chiral discrimination effect from the (R,R)-selector in the 1H-NMR spectra of a mixture of the enantiomers of O,O'-dibenzoyltartaric acid was studied as a function of temperature. Due to certain ambiguities in the literature concerning the absolute configuration of the (+)-rotating trans-acenaphthen-1,2-dicarboxylic acid, its brucine salt was subjected to X-ray crystallography. This showed the (+)-form to be of (R,R)-configuration.