How to recognize a suitable pancreas donor: a Eurotransplant study of preprocurement factors.

INTRODUCTION: Because of the increasing demand for pancreas transplantation, more marginal donors are offered to Eurotransplant. The aim of this study was to validate a donor quality score that would facilitate recognition of a suitable pancreas donor among all reported donors. MATERIALS AND METHODS: We analyzed all 3180 consecutively reported pancreas donors for the period between January 1, 2002 and June 30, 2005 and determined the influence of the preprocurement pancreas suitability score (P-PASS) on the acceptance of a pancreas. We defined a range and point weight for each variable based on clinical expertise and known literature. RESULTS: Multiple regression analysis using pancreas acceptance as an outcome variable identified P-PASS > or = 17 as a significant cutoff point (P < .001). Pancreata from donors with P-PASS > or = 17 were three times more likely to be refused. CONCLUSION: The donor score can help in screening for potential pancreas donors, where an ideal donor has a P-PASS < 17. Our data demonstrate that consideration of a combination of preprocurement factors can help identify a suitable pancreas donor. Therefore, we recommend that a pancreas donor score be calculated for each potential pancreas donor, and all donors with a P-PASS < 17 should be considered for pancreas donation.

Involvement of dendritic cells in allograft rejection new implications of dendritic cell-endothelial cell interactions.

For almost half a century immunologists have tried to tear down the MHC barrier, which separates two unrelated individuals during transplantation. Latest experimental data suggest that a breakthrough in vitro is imminent. Dendritic cells (DCs), which activate naïve allo-reactive T-cells (TCs), play a central role in the establishment of allo-antigen-specific immunity. Allograft solid organ rejection is initiated at the foreign endothelial cell (EC) layer, which forms an immunogenic barrier for migrating DCs. Thus, DC/EC interactions might play a crucial role in antigen-specific allograft rejection. Organ rejection is mediated by host allo-reactive TCs, which are activated by donor DCs (direct activation) or host DCs (indirect activation). Direct allo-antigen presentation by regulatory dendritic cells (DCreg) can play an instructive role towards tolerance induction. Several groups established that, DCregs, if transplanted beforehand, enter host thymus, spleen, or bone marrow where they might eventually establish allo-antigen-specific tolerance. A fundamental aspect of DC function is migration throughout the entire organism. After solid organ transplantation, host DCs bind to ECs, invade allograft tissues, and finally transmigrate into lymphoid vessels and secondary lymphoid organs, where they present allo-antigens to naïve host TCs. Recent data suggest that in vitro manipulated DCregs may mediate allo-transplantation tolerance induction. However, the fundamental mechanisms on how such DCregs cause host TCs in the periphery towards tolerance remain unclear. One very promising experimental concept is the simultaneous manipulation of DC direct and indirect TC activation/suppression, towards donor antigen-specific allo-transplantation tolerance. The allo-antigen-specific long-term tolerance induction mediated by DCreg pre-transplantation (with simultaneous short-term immunosuppression) has become reproducible in the laboratory animal setting. Despite the shortcomings of laboratory animal studies, strong promises are deriving from these studies for clinical kidney, heart, and liver transplantation.

Renal ischemia-reperfusion injury: new implications of dendritic cell-endothelial cell interactions.

In renal ischemia/reperfusion (I/R) injury endothelial cells are a main target. The disturbance of endothelial cell physiology leads to endothelial swelling and narrowing of the blood vessel lumen. We attribute this effect to impairment of endothelial cell nitric oxide synthase (NOS). NO is significantly reduced in the course of hypoxia causing dysfunction of the vascular smooth muscle tone. Subsequently to an I/R injury, the inflammatory response results in endothelial activation with enhanced dendritic cell (DC) adhesion and migration. Thus, alloreactive leukocytes are recruited to the inflammatory site. Finally, dendritic cell-endothelial cell interactions may play a crucial role in antigen-specific allograft rejection in I/R renal injury. DCs, which activate naïve alloreactive T cells, play a central role in the establishment of alloantigen-specific immunity. In the course of hypoxia rejection is initiated at the activated layer of foreign endothelial cells (EC), which forms an immunogenic barrier for migrating DCs and T cells. Host DCs that bind to postischemic activated ECs invade the allografted tissues, or remain stationary in the subendothelial layer, or transmigrate into lymphoid vessels and secondary lymphoid organs, where they present alloantigens to naïve host T cells. Organ rejection is mediated by host alloreactive T cells, which are activated by donor DCs (direct activation) or host DCs (indirect activation). We hypothesized that DC-EC binding and migration is the first step in the renal I/R injury that mediates allotransplant rejection. We sought to better understand the downstream events of a renal I/R injury by understanding DC binding and migration, thereby seeking new strategies for more specific immunomodulatory interventions. Herein we developed a new allotransplant-rejection model after renal I/R injury.

Dendritic cells as pharmacological targets for the generation of regulatory immunosuppressive effectors. New implications for allo-transplantation.

Dendritic cells (DCs) play a central role in the establishment of tolerance/immunity, because they activate naïve T cells (TCs). Therefore, the pharmacological modulation of DCs has become a major field of interest in immunology. A large body of literature has arisen from the studies of DC biology during immunosuppressive drug treatment. Immunosuppressive drugs have improved the therapeutic management of allograft organ transplantation and autoimmune diseases, significantly. There is now strong evidence that, DCs might be the key for antigen specific tolerance induction. Recently, the existence of a population of DCs that migrate to the regional lymph node in the steady state has been identified. Such steady state immature migrating DCs are loaded with tissue antigens and deliver self-antigens towards secondary lymphatic organs and might educate TCs towards self-tolerance. Latest experimental data from rodent solid organ allo-transplantation supports the idea, that DCs might even become regulatory DCs towards foreign antigen specific tolerance induction. Apparently, regulatory donor DCs invade host secondary lymphatic organs where they might eventually educate host TCs towards foreign antigen specific tolerance. Seemingly, it depends on the DC maturation state whether pharmacologically modulated DCs induce antigen specific long-term tolerance in allo-transplantation solid organ transplantation. Several authors reported a positive self-limiting feedback loop between tolerogenic DCs and allo-specific regulatory TCs. Thus, the DC-TC network appears as an exceptionally good target for pharmacological manipulations. Here we review how immunosuppressive agents interfere with DC maturation, migration and homeostasis. We are developing a rational to select different drugs for the generation of regulatory DCs, for allo-transplantation clinical settings.

Islet autotransplantation combined with pancreatectomy for treatment of pancreatic adenocarcinoma: a case report.

Extensive pancreatectomy (EP) may increase the resection rate of pancreatic adenocarcinoma (PA). Unfortunately, EP often results in unstable diabetes. Recently, islet autotransplantation (auto-Tx) has offered the potential to prevent this metabolic disorder. Because of the fear of contamination of prepared islets by malignant cells, this procedure has so far not been used as a treatment for PA. We herein report a case of a 63-year-old nondiabetic patient who underwent EP combined with islet auto-Tx in an emergency operation following histologically proved R(0)-resection for PA (pT(3)pN(1)G(2)). Islets were isolated from the excised pancreas using a continuous digestion filtration device. The resultant preparation was injected into the portal vein. Owing to the moderate fasting hyperglycemia, postoperative exogenous insulin therapy was necessary (26 U/d). After discharge, the patient's daily insulin dose was gradually reduced. At 1-year follow-up the fasting C-peptide level was 0.66 ng/mL, and an oral glucose tolerance test (oGTT) and an intravenous (IV) glucagon stimulation (GS) showed functioning engrafted islets. The K-ras mutations were detected in the paraffin-embedded PA, but not in the prepared islets or in the peripheral blood. Computed tomographic (CT) imaging revealed neither local tumor recurrence nor liver metastases. At 2-year follow-up, the patient was on a balanced food regimen and gaining weight. Although he remains insulin-dependent (16 U/d), he is metabolically stable (HbA(1)(c) 5.9%). The fasting C-peptide level is 0.68 ng/mL. The peak value of C-peptide in response to oGTT was 0.92 ng/mL and to GS 0.89 ng/mL. At this time Ca19-9 and CEA are increased to 35.3 U/mL and 19.2 ng/mL, respectively. The patient died 2.5 years after operation owing to tumor recurrence. There was no evidence for liver metastases. We postulate that histologic evaluation (R(0)-resection) and detection of K-ras mutations may be useful techniques. However, islet auto-Tx after EP for adenocarcinoma should only be regarded for rescue therapy. Studies on strategies to exclude possible contamination of islet tissue with carcinoma cells are critically important.

Dendritic cell endothelium interaction in autoimmunity.

Monocyte derived dendritic cells play a central role in controlling immunity by activating naïve T lymphocytes. Monocytes can leave the blood stream by endothelial cell transmigration and differentiation into dendritic cells. A fundamental aspect of dendritic cell biology is their capacity to engulf tissue antigens and revers-migrate into lymph nodes. In lymph nodes dendritic cells can traffic to T-cell areas where they activate naïve T-cells. Throughout this review we are developing a model of in vivo activation of auto-reactive T-cells by activated dendritic cells.

High levels of C-reactive protein after simultaneous pancreas-kidney transplantation predict pancreas graft-related complications and graft survival.

BACKGROUND: Although pancreas graft-related complications are frequent after simultaneous pancreas-kidney transplantation (SPK), there are no parameters predicting the risk for these complications. METHOD: A two-center retrospective study was performed in 97 patients who underwent SPK to investigate the peak serum value of c-reactive protein (CRP) during the first 72 hr after SPK in view of graft-related complications and graft survival. RESULTS: Mean peak CRP was 115.6 +/- 71.5 mg/L. Mean peak CRP was higher in patients needing relaparotomy (n=31) (136.4 vs. 105.8 mg/L, P=0.048), especially when postoperative bleeding was excluded (P=0.015); in patients with graft pancreatitis (P=0.03); and in patients with graft loss (n=19; P<0.001) compared with patients without these complications. With a cut-off of peak CRP at the level of mean plus 1 SD (187.05 mg/L), there was a significantly higher incidence of relaparotomies (P=0.01; bleedings excluded: P=0.003), graft pancreatitis (P=0.03), and pancreas graft loss (P<0.0001) in patients with high peak CRP compared with patients with low peak CRP. No differences were noticed with regard to rejection rate, mortality, and kidney graft loss. CONCLUSION: Our findings suggest that peak CRP is a helpful parameter in predicting pancreas graft-related complications and pancreas graft survival after SPK. Our results also stress the importance of early graft damage in pancreas transplantation.

Low frequency of p53 and ras mutations in bile of patients with hepato-biliary disease: a prospective study in more than 100 patients.

The diagnosis of biliary disease, namely malignant disorders, is frequently hampered by the inconclusive cytology. We investigated prospectively the frequency of molecular changes in p53 and ras compared with cytology in patients with primary or secondary hepato-biliary disease. We investigated 118 consecutive patients, aged 24-89 with the following clinical diagnoses: choledocho/cholecystolithiasis (28), cholangiocellular carcinoma (21), gall bladder tumor (8), liver metastasis (3), autoimmune disease (8), chronic pancreatitis (16), pancreatic carcinoma (11), papillary disease (4), hepatic cirrhosis (6), cholangitis (2), anomalies (2), and normal (9). Bile was aspirated during routine endoscopic retrograde cholangio pancreatography (ERCP) or percutaneous transhepatic cholangiography (PTC). DNA was prepared freshly from a native aliquot. p53 mutations were detected by polymerase chain reaction (PCR) for exons 5 through 8 followed by TGGE. PCR for ras mutations was performed as RFLP-PCR with sequencing. In four cases, mutations in p53 could be found in exons 6 and 7. Twenty-two samples showed ras mutations; ras mutations were found in choledocholithiasis (4/28), bile duct (5/21), gall bladder (3/8) and pancreatic (1/11) carcinoma, liver metastasis (3/3), ulcerative colitis (2/3), PSC (1/2), and chronic pancreatitis (1/16). Cytology was clearly positive in seven cases, suspicious in three other, inconclusive in six, and negative in the rest. The molecular analysis resulted in a sensitivity of 33% and specificity of 87%, respectively, for the diagnosis of a malignant condition. PCR for p53 and ras mutations may aid the diagnosis of primary and secondary (metastatic) hepatobiliary disease if a malignant condition of the bile ducts and the liver is suspected and cytology is inconclusive or negative. However, the incidence of p53 and ras mutations in bile seems less frequent than in other malignant conditions of the gastrointestinal tract and the pancreas and lower than in tissue, leaving a poor sensitivity and specificity. Nevertheless, the presence of a p53 and/or ras mutation per se supports a clinical suspicion of malignancy, even when the conventional cytology is negative or inconclusive.

[Pancreatic transplantation: success and problems]. / Pankreastransplantation: Erfolge und Probleme.

The results of pancreatic transplantation could be improved markedly since using the bladder drainage technique. The best function rates can be achieved when transplanting simultaneously a kidney from the same donor. In our own series of 50 combined pancreas-/kidney transplantations (CPKT) the 1-year-graft function rate for both organs reaches 88%. The drainage of the exocrine pancreatic secretions into the urinary tract leads, however, to a high incidence of recurrent urinary tract infections. Diagnosis of rejections after combined pancreas-/kidney transplantation is mainly based on the function of the simultaneously transplanted kidney and the exocrine secretion of the pancreatic graft. In spite of triple drug therapy (prednisolone, azathioprine, cyclosporine A) and ATG (antithymocyte globulin) prophylaxis the incidence of acute rejection episodes is initially high. For rejection therapy monoclonal antibodies, such as OKT3, are most effective. Glucose metabolism is almost completely normalized after successful pancreatic transplantation. Considering late diabetic complications, however, only positive effects on diabetic neuropathy are confirmed. This is probably due to the very late onset of therapy by pancreatic transplantation. A significant improvement in other late diabetic complications can only be expected in long term follow up studies. The positive effect on physical and psychological rehabilitation, however, improves the quality of life in most of the patients after CPKT substantially. Even though the results of isolated pancreatic transplantation reaches 1-year-graft function rates of approximately 60% in single centers, the indication to this treatment should consider the disadvantages of long term immunosuppression and the uncertain results considering secondary complications.(ABSTRACT TRUNCATED AT 250 WORDS)

[The management of exocrine pancreatic secretion--a central problem of allogeneic pancreas transplantation]. / Management der exokrinen Pankreassekretion--ein zentrales Problem der allogenen Pankreastransplantation.

In a consecutive series of 47 pancreatic transplantations, the duct occlusion technique and the bladder drainage technique are evaluated. Major problems, when using the duct occlusion technique are pancreatic fistulae with secondary infections and bleedings. Early postoperative graft thrombosis remains a crucial problem. Finally, graft rejection can not be diagnosed in time when using the duct occlusion technique. In contrast, the bladder drainage technique guarantees an absolutely safe management of the exocrine pancreas secretion. The risk of early postoperative graft thromboses reaches nearly zero. In addition, by monitoring urinary amylase and thereby the function of the exocrine pancreas, rejection episodes can be diagnosed very early. Early postoperative graft pancreatitis of the bladder drained pancreatic allografts remains a significant problem. In addition due to excessive bicarbonate loss via the urine oral bicarbonate substitution is necessary. A high incidence of urinary tract infections as well as unspecific irritations of the urinary tract are further drawbacks of the bladder drainage technique. They can be managed, however, relatively easily. Since using the bladder drainage technique, 1-year-graft-function rate of the pancreatic allografts increased by more than 40% and reaches now 88%. The new operative technique represents the best surgical procedure for control of the exocrine secretion of pancreatic allografts at the moment. Simultaneous pancreas-/kidney transplantation in the technique described can therefore be recommended a selected group of type-I diabetics with end-stage renal disease as the therapy of choice.

The bladder drainage technique in pancreas transplantation--the Tübingen experience.

Starting in 1987 renal- and pancreaticoduodenal--transplantations were performed simultaneously in a consecutive series of 40 patients with Type 1 diabetes mellitus and end-stage renal disease. Exocrine secretion of the pancreatic graft does not seem to be a crucial problem anymore when using the bladder drainage technique. No pancreatic fistulae were seen. No graft lost its function due to early post-operative graft thrombosis. Early post-operative graft pancreatitis and recurrent urinary tract infections remain the drawbacks of the bladder drainage technique. Despite a strong immunestimulation of the recipient by the combined pancreaticoduodenal/renal allograft all but two rejection episodes could be reversed by using different monoclonal/polyclonal antibodies. Actuarial 1-year-graft survival rate reaches 85% for the pancreas as well as the kidney. Thus, simultaneous pancreas-kidney transplantation can be performed with a high success rate when using the technique described.

Glycogen effects on energy state and passive electric properties of liver during protection.

In order to evaluate the importance of glycogen for the hepatic tolerance to ischemia, livers of swine fed a glucose-potassium solution for premedication were perfused with either Bretschneider's HTK-solution (histidine-tryptophan-ketoglutarate) or with Euro-Collins-solution (EC) prior to subsequent ischemia at 25 and 5 degrees C. During ischemia, in regular intervals or continuously, energy rich phosphates, lactate, intrahepatic pH and the electrical impedance of liver tissue were determined. The results were compared with corresponding data from swine which had starved for 48 h. Corresponding to the higher glycogen content, energy supply during ischemia was markedly improved by the premedication. Despite high amounts of glucose in the EC-solution, energy supply after glucose-potassium premedication was no better with EC-solution than with HTK-solution. Moreover, glucose uptake led to concomitant cellular water uptake. Electrical impedance measurements during ischemia mirrored improved energetical protection by the glucose-potassium premedication.