Pancreas Transplantation With Grafts From Donors Deceased After Circulatory Death: 5 Years Single-Center Experience.

BACKGROUND: Donation after circulatory death (DCD) pancreas transplantation has been shown to be an additional way to deal with donor organ shortages. The results of 5-year DCD pancreas transplantation are presented. METHODS: A retrospective, single-center analysis (2011-2015) was performed to compare the results of donation after brain death (DBD) to DCD pancreas transplantation. RESULTS: During the study period, 104 pancreas transplantations (83 from DBD and 21 from DCD) were performed. Median Pancreas Donor Risk Index (PDRI) was 1.47, (DBD, 1.61 vs DCD, 1.35; P = 0.144). Without the factor DCD, PDRI from DCD donors was significantly lower (DBD, 1.61 vs DCD, 0.97; P < 0.001). Donor age was the only donor-related risk factor associated with pancreas graft survival (Hazard ratio, 1.06; P = 0.037). Postoperative bleeding and kidney delayed graft function occurred more frequently in recipients from DCD (P = 0.006). However, DCD pancreata had a lower incidence of thrombosis. Kidney and pancreas graft survival were equally good in both groups. CONCLUSIONS: Pancreas transplantation from DCD donors yields comparable results to DBD donors when PDRI of DCD is relatively low. Most DCD donors are younger donors with trauma as cause of death. These DCD pancreas grafts may be a better option to cope with increasing organ shortages than exploring the limits with older (and higher PDRI) DBD donors.

Succinate Accumulation and Ischemia-Reperfusion Injury: Of Mice but Not Men, a Study in Renal Ischemia-Reperfusion.

A recent seminal paper implicated ischemia-related succinate accumulation followed by succinate-driven reactive oxygen species formation as a key driver of ischemia-reperfusion injury. Although the data show that the mechanism is universal for all organs tested (kidney, liver, heart, and brain), a remaining question is to what extent these observations in mice translate to humans. We showed in this study that succinate accumulation is not a universal event during ischemia and does not occur during renal graft procurement; in fact, tissue succinate content progressively decreased with increasing graft ischemia time (p < 0.007). Contrasting responses were also found with respect to mitochondrial susceptibility toward ischemia and reperfusion, with rodent mitochondria robustly resistant toward warm ischemia but human and pig mitochondria highly susceptible to warm ischemia (p < 0.05). These observations suggest that succinate-driven reactive oxygen formation does not occur in the context of kidney transplantation. Moreover, absent allantoin release from the reperfused grafts suggests minimal oxidative stress during clinical reperfusion.

A change in inflammatory footprint precedes plaque instability: a systematic evaluation of cellular aspects of the adaptive immune response in human atherosclerosis.

BACKGROUND: Experimental studies characterize adaptive immune response as a critical factor in the progression and complications of atherosclerosis. Yet, it is unclear whether these observations translate to the human situation. This study systematically evaluates cellular components of the adaptive immune response in a biobank of human aortas covering the full spectrum of atherosclerotic disease. METHODS AND RESULTS: A systematic analysis was performed on 114 well-characterized perirenal aortic specimens with immunostaining for T-cell subsets (CD3/4/8/45RA/45RO/FoxP3) and the Th1/non-Th1/Th17 ratio (CD4(+)T-bet(+)/CD4(+)T-bet(-)/CD4(+)/interleukin-17(+) double staining). CD20 and CD138 were used to identify B cells and plasma cells, while B-cell maturation was evaluated by AID/CD21 staining and expression of lymphoid homeostatic CXCL13. Scattered CD4 and CD8 cells with a T memory subtype were found in normal aorta and early, nonprogressive lesions. The total number of T cells increases in progressive atherosclerotic lesions (≈1:5 CD4/CD8 T-cell ratio). A further increase in medial and adventitial T cells is found upon progression to vulnerable lesions.This critical stage is further hallmarked by de novo formation of adventitial lymphoidlike structures containing B cells and plasma cells, a process accompanied by transient expression of CXCL13. A dramatic reduction of T-cell subsets, disappearance of lymphoid structures, and loss of CXCL13 expression characterize postruptured lesions. FoxP3 and Th17 T cells were minimally present throughout the atherosclerotic process. CONCLUSIONS: Transient CXCL13 expression, restricted presence of B cells in human atherosclerosis, along with formation of nonfunctional extranodal lymphoid structures in the phase preceding plaque rupture, indicates a "critical" change in the inflammatory footprint before and during plaque destabilization.

Microvascular damage in type 1 diabetic patients is reversed in the first year after simultaneous pancreas-kidney transplantation.

Simultaneous pancreas-kidney transplantation (SPK) is an advanced treatment option for type 1 diabetes mellitus (DM) patients with microvascular disease including nephropathy. Sidestreamdarkfield (SDF) imaging has emerged as a noninvasive tool to visualize the human microcirculation. This study assessed the effect of SPK in diabetic nephropathy (DN) patients on microvascular alterations using SDF and correlated this with markers for endothelial dysfunction. Microvascular morphology was visualized using SDF of the oral mucosa in DN (n = 26) and SPK patients (n = 38), healthy controls (n = 20), DM1 patients (n = 15, DM ≥ 40 mL/min) and DN patients with a kidney transplant (KTx, n = 15). Furthermore, 21 DN patients were studied longitudinally up to 12 months after SPK. Circulating levels of angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2) and soluble thrombomodulin (sTM) were measured using ELISA. Capillary tortuosity in the DN (1.83 ± 0.42) and DM ≥ 40 mL/min (1.55 ± 0.1) group was increased and showed reversal after SPK (1.31 ± 0.3, p < 0.001), but not after KTx (1.64 ± 0.1). sTM levels were increased in DN patients and reduced in SPK and KTx recipients (p < 0.05), while the Ang-2/Ang-1 ratio was normalized after SPK and not after KTx alone (from 0.16 ± 0.04 to 0.08 ± 0.02, p < 0.05). Interestingly, in the longitudinal study, reversal of capillary tortuosity and decrease in Ang-2/Ang-1 ratio and sTM was observed within 12 months after SPK. SPK is effective in reversing the systemic microvascular structural abnormalities in DN patients in the first year after transplantation.

Randomized trial of short-course high-dose erythropoietin in donation after cardiac death kidney transplant recipients.

Eryhropoiesis-stimulating agents have demonstrated tissue-protective effects in experimental models of ischemia-reperfusion injury. PROTECT was a 12-month, randomized, double-blind, placebo-controlled, single center study with high-dose recombinant human erythropoietin-ß (Epoetin) in 92 donation after cardiac death (DCD) kidney transplant recipients. Patients were randomized to receive an intravenous bolus of Epoetin (3.3 × 10(4) international unit (IU); n = 45) or placebo (saline 0.9% solution; n = 47) on 3 consecutive days, starting 3-4 h before the transplantation and 24 h and 48 h after reperfusion. The immunosuppressive regimen included an anti-CD25 antibody, steroids, mycophenolate mofetil and delayed introduction of cyclosporine. Primary end point was a composite of the incidence of primary nonfunction and delayed graft function, either defined by spontaneous functional recovery or need for dialysis in the first week. Secondary objectives included duration of delayed function, renal function and proteinuria up to 1 year and thrombotic adverse events. Results showed no differences in the incidence or duration of delayed graft function and/or primary nonfunction (Epoetin 77.8 vs. placebo 78.7%, p = 1.00). Epoetin treatment significantly increased the risk of thrombotic events at 1 month and 1 year (Epoetin 24.4% vs. placebo 6.4%, p = 0.02).

Visualizing TGF-ß and BMP signaling in human atherosclerosis: a histological evaluation based on Smad activation.

BACKGROUND: The TGF-ß superfamily members transforming growth factor-ß (TGF-ß/Activin) and bone morphogenetic proteins (BMP) have been implicated in the pathogenesis of atherosclerosis. However, their role in human disease remains controversial. In this study we used Smad phosphorylation as a read out for TGF-ß and BMP signaling during the initiation, progression and (de)stabilization of human atherosclerotic disease. MATERIAL AND METHODS: A systematic analysis was performed in 114 peri-renal aortic patches (stained with Movat Pentachrome, H&E, pSmad2, pSmad1,5,8 and PAI-1) covering the entire atherosclerotic spectrum (van Dijk, 2010). Immunostaining against T-cells (CD3) and monocytes and macrophages (CD68) was used to explore a putative association between TGF-ß and BMP signaling and vascular inflammation. RESULTS: Smad phosphorylation was present within the normal arterial wall in approximately 10% of the endothelial cells and intimal smooth muscle cells. A significant increase in pSmad2 and pSmad1,5,8 positivity was found in non-progressive lesions (>50% positivity). No further increase or decrease was found in the progressive atherosclerotic lesions, vulnerable and stabilized lesions. No association was found between TGF-ß and BMP signaling and CD3 and CD68 expression, nor cap thickness. CONCLUSION: Activation of the TGF-ß and BMP pathways is an early event in atherosclerotic lesion formation. No significant relationships were found between Smad phosphorylation and vessel wall inflammation or plaque vulnerability.

Timing of cholecystectomy after mild biliary pancreatitis.

BACKGROUND: The aim of the study was to evaluate recurrent biliary events as a consequence of delay in cholecystectomy following mild biliary pancreatitis. METHODS: Between 2004 and 2007, patients with acute pancreatitis were registered prospectively in 15 Dutch hospitals. Patients with mild biliary pancreatitis were candidates for cholecystectomy. Recurrent biliary events requiring admission before and after cholecystectomy, and after endoscopic sphincterotomy (ES), were evaluated. RESULTS: Of 308 patients with mild biliary pancreatitis, 267 were candidates for cholecystectomy. Eighteen patients underwent cholecystectomy during the initial admission, leaving 249 potential candidates for cholecystectomy after discharge. Cholecystectomy was performed after a median of 6 weeks in 188 patients (75·5 per cent). Before cholecystectomy, 34 patients (13·7 per cent) were readmitted for biliary events, including 24 with recurrent biliary pancreatitis. ES was performed in 108 patients during the initial admission. Eight (7·4 per cent) of these patients suffered from biliary events after ES and before cholecystectomy, compared with 26 (18·4 per cent) of 141 patients who did not have ES (risk ratio 0·51, 95 per cent confidence interval 0·27 to 0·94; P = 0·015). Following cholecystectomy, eight (3·9 per cent) of 206 patients developed biliary events after a median of 31 weeks. Only 142 (53·2 per cent) of 267 patients were treated in accordance with the Dutch guideline, which recommends cholecystectomy or ES during the index admission or within 3 weeks thereafter. CONCLUSION: A delay in cholecystectomy after mild biliary pancreatitis carries a substantial risk of recurrent biliary events. ES reduces the risk of recurrent pancreatitis but not of other biliary events.

Donor brain death predisposes human kidney grafts to a proinflammatory reaction after transplantation.

Donor brain death has profound effects on post-transplantation graft function and survival. We hypothesized that changes initiated in the donor influence the graft's response to ischemia and reperfusion. In this study, human brain dead donor kidney grafts were compared to living and cardiac dead donor kidney grafts. Pretransplant biopsies of brain dead donor kidneys contained notably more infiltrating T lymphocytes and macrophages. To assess whether the different donor conditions result in a different response to reperfusion, local cytokine release from the reperfused kidney was studied by measurement of paired arterial and renal venous blood samples. Reperfusion of kidneys from brain dead donors was associated with the instantaneous release of inflammatory cytokines, such as G-CSF, IL-6, IL-9, IL-16 and MCP-1. In contrast, kidneys from living and cardiac dead donors showed a more modest cytokine response with release of IL-6 and small amounts of MCP-1. In conclusion, this study shows that donor brain death initiates an inflammatory state of the graft with T lymphocyte and macrophage infiltration and massive inflammatory cytokine release upon reperfusion. These observations suggest that brain dead donors require a novel approach for donor pretreatment aimed at preventing this inflammatory response to increase graft survival.

The natural history of aortic atherosclerosis: a systematic histopathological evaluation of the peri-renal region.

BACKGROUND: Risk factor profiles for the different vascular beds (i.e. coronary, carotid, peripheral and aortic) are remarkably different, suggesting that atherosclerosis is a heterogeneous disorder. Little is known about the morphologic progression of atherosclerosis in the peri-renal aorta, one of the primary predilection sites of atherosclerosis. METHODS: A systematic analysis was performed in 260 consecutive peri-renal aortic patches (stained with Movat Pentachrome and H&E) collected during organ transplantation (mean donor age 46.5 (range 5-76) years; 54% male symbol; mean BMI 24.9; 40% smokers; 20% hypertensive). Plaque morphology was classified according to the modified AHA classification scheme proposed by Virmani et al. [4]. Immunostaining against CD68 was used to identify the distribution of intimal macrophages and monocytes in several predefined locations among various plaque types and fibrous cap thickness. RESULTS: There was significant intimal thickening (p<0.013) and medial thinning (p<0.032) with advancing age. The incidence of atherosclerotic plaques in the abdominal aorta correlated with age (r=0.640, p=0.01). During the first three decades of life adaptive intimal thickening and intimal xanthomas were the predominant lesions. In contrast, the fourth, fifth and sixth decades hallmarked more complicated plaques of pathological intimal thickening, early and late fibroatheromas (EFAs and LFAs), thin-cap FAs (TCFAs; cap thickness <155 microm), ruptured plaques (PRs), healed rupture and fibrotic calcified plaques. The mean percentage of lesional macrophages increased significantly from LFAs to TCFAs (5-17%; p<0.001). Macrophage infiltration of the fibrous cap was negatively correlated with fibrous cap thickness (p<0.0004); TCFAs and PRs (caps<100 microm) contained significantly more macrophages (19%) compared with caps 101-300 microm (6%) and >300 microm (2%). Macrophages in shoulder regions were highest in early and late FAs ( approximately 45%) followed by TCFAs (27%) and PR (20%). Further, intimal vasa vasorum were mostly seen adjacent to the necrotic core of advanced atherosclerotic plaques and remained confined to the intimo-medial border despite marked thickening of the intima. CONCLUSION: This study shows that peri-renal aortic atherosclerosis starts early in life. Gross plaque morphologies of the peri-renal abdominal aorta are similar to coronary atherosclerosis yet indications were found for site specific differences in macrophage content and neovascularization.

Early renal ischemia-reperfusion injury in humans is dominated by IL-6 release from the allograft.

The pathophysiology of ischemia/reperfusion (I/R) injury is complex, and current knowledge of I/R injury in humans is incomplete. In the present study, human living-donor kidney transplantation was used as a highly reproducible model to systematically study various processes potentially involved in early I/R injury. Unique, direct measurements of arteriovenous concentration differences over the kidney revealed massive release of interleukin (IL)-6 in the first 30 minutes of graft reperfusion and a modest release of IL-8. Among the assessed markers of oxidative and nitrosative stress, only 15(S)-8-iso-PGF(2alpha) was released. When assessing cell activation, release of prothrombin factor 1 + 2 indicated thrombocyte activation, whereas there was no release of markers for endothelial activation or neutrophil activation. Common complement activation complex sC5b-9 was not released into the bloodstream, but was released into urine rapidly after reperfusion. To investigate whether IL-6 plays a modulating role in I/R injury, a mouse experiment of renal I/R injury was performed. Neutralizing anti-IL-6 antibody treatment considerably worsened kidney function. In conclusion, this study shows that renal I/R in humans is dominated by local IL-6 release. Neutralization of IL-6 in mice resulted in a significant aggravation of renal I/R injury.

Timing and impact of infections in acute pancreatitis.

BACKGROUND: Although infected necrosis is an established cause of death in acute pancreatitis, the impact of bacteraemia and pneumonia is less certain. METHODS: This was a cohort study of 731 patients with a primary episode of acute pancreatitis in 2004-2007, including 296 patients involved in a randomized controlled trial to investigate the value of probiotic treatment in severe pancreatitis. Time of onset of bacteraemia, pneumonia, infected pancreatic necrosis, persistent organ failure and death were recorded. RESULTS: The initial infection in 173 patients was diagnosed a median of 8 (interquartile range 3-20) days after admission (infected necrosis, median day 26; bacteraemia/pneumonia, median day 7). Eighty per cent of 61 patients who died had an infection. In 154 patients with pancreatic parenchymal necrosis, bacteraemia was associated with increased risk of infected necrosis (65 versus 37.9 per cent; P = 0.002). In 98 patients with infected necrosis, bacteraemia was associated with higher mortality (40 versus 16 per cent; P = 0.014). In multivariable analysis, persistent organ failure (odds ratio (OR) 18.0), bacteraemia (OR 3.4) and age (OR 1.1) were associated with death. CONCLUSION: Infections occur early in acute pancreatitis, and have a significant impact on mortality, especially bacteraemia. Prophylactic strategies should focus on early intervention.

Accumulation of autoreactive effector T cells and allo-specific regulatory T cells in the pancreas allograft of a type 1 diabetic recipient.

AIMS/HYPOTHESIS: Simultaneous kidney-pancreas transplantation is an established treatment for patients with type 1 diabetes and end-stage renal failure, even though restored beta cell function may become affected by recurrent islet autoimmunity or graft rejection. We characterised infiltrating lymphocytes isolated from a pancreatic graft with normal endocrine function in a kidney-pancreas recipient with type 1 diabetes. METHODS: The pancreas graft was removed due to recurrent graft pancreatitis of unknown cause. Pancreas-infiltrating lymphocytes and peripheral blood mononuclear cells (PBMC) were isolated and characterised phenotypically and functionally. RESULTS: Compared with PBMC, pancreas-infiltrating lymphocytes exhibited a distinct activation/memory phenotype and T cell receptor profile that were indicative of selective infiltration of the pancreas. Islet autoreactive CD8(+) T cells could be detected in the pancreas and were increased in frequency compared with PBMC. Additionally, an augmentation of CD8(+) CD28(-) regulatory T cells was observed in the pancreas; these induced expression of the inhibitory receptor immunoglobulin-like transcript-3 on antigen-presenting cells in a donor HLA class I-specific manner. CONCLUSIONS/INTERPRETATION: These data demonstrate the simultaneous presence of regulatory and effector T cells in the pancreas allograft of a recipient with type 1 diabetes. They also indicate that circulating islet autoreactive T cells may reflect immunological processes in pancreatic tissue, even though their frequency in the periphery may lead to underestimation of their presence in the pancreas. Additional specificities were also present in the pancreas that were undetectable in the circulation.

Transfer of ureteral carcinoma in a transplanted kidney presenting by early stenosis of the proximal ureter.

A 71-yr-old male kidney transplant recipient suffered from delayed graft function. Eighty days after transplantation complete obstruction of the proximal ureter was observed, complicated by recurrent urinary tract infections. Two months later, the donor kidney was removed because of infectious complications and inadequate arterial perfusion. Histological examination of the removed graft showed signs of rejection as well as a low-grade papillary urothelial cell carcinoma of donor origin in the ureter. The remaining donor ureter was removed subsequently and showed no further signs of malignancy. Follow-up of the patient until 12 months after surgery did not reveal recurrence of the tumor. This case report is the first to describe accidental transfer of urothelial cell carcinoma in the ureter by transplantation, highlighting the possibility of malignancy when early stenosis is not related to the anastomosis. It again emphasizes the need for precise and cautious screening of organ donors, especially those of higher age.

[Probiotic prophylaxis in patients with predicted severe acute pancreatitis: a randomised, double-blind, placebo-controlled trial]. / Probioticaprofylaxe bij voorspeld ernstige acute pancreatitis: een gerandomiseerde, dubbelblinde, placebogecontroleerde trial.

OBJECTIVE: To evaluate whether enteral prophylaxis with probiotics in patients with predicted severe acute pancreatitis prevents infectious complications. DESIGN: Multicentre, randomised, double-blind, placebo-controlled trial. METHOD: A total of 296 patients with predicted severe acute pancreatitis (APACHE II score > or = 8, Imrie score > or = 3 or C-reactive protein concentration > 150 mg/l) were included and randomised to one of two groups. Within 72 hours after symptom onset, patients received a multispecies preparation of probiotics or placebo given twice daily via a jejunal catheter for 28 days. The primary endpoint was the occurrence of one of the following infections during admission and go-day follow-up: infected pancreatic necrosis, bacteraemia, pneumonia, urosepsis or infected ascites. Secondary endpoints were mortality and adverse reactions. The study registration number is ISRCTN38327949. RESULTS: Treatment groups were similar at baseline with regard to patient characteristics and disease severity. Infections occurred in 30% of patients in the probiotics group (46 of 152 patients) and 28% of those in the placebo group (41 of 144 patients; relative risk (RR): 1.1; 95% CI: 0.8-1.5). The mortality rate was 16% in the probiotics group (24 of 152 patients) and 6% (9 of 144 patients) in the placebo group (RR: 2.5; 95% CI: 1.2-5.3). In the probiotics group, 9 patients developed bowel ischaemia (of whom 8 patients died), compared with none in the placebo group (p = 0.004). CONCLUSION: In patients with predicted severe acute pancreatitis, use of this combination of probiotic strains did not reduce the risk of infections. Probiotic prophylaxis was associated with a more than two-fold increase in mortality and should therefore not be administered in this category of patients.

Reuse of auxiliary liver grafts in second recipients with chronic liver disease.

We describe the first cases of reuse of auxiliary liver grafts for orthotopic transplantation in chronic liver disease. A reduced liver graft (segments 2, 3, half of 4) was first transplanted auxiliary for acute liver failure using a new technique. After regeneration of both native liver and graft, the auxiliary graft was removed and immunosuppression discontinued in the first recipients. After informed consent of donors and recipients, both auxiliary grafts were then orthotopically transplanted into second recipients. Both grafts function normally. Reuse of auxiliary grafts may help to reduce the shortage or liver grafts available for transplantation.

Life-saving therapy for haemorrhaging liver adenomas using selective arterial embolization.

BACKGROUND: Emergency treatment for patients with a ruptured hepatocellular adenoma is controversial. The aim of this study was to evaluate management with selective arterial embolization. METHODS: The study included 11 consecutive patients treated for ruptured hepatocellular adenomas between 2001 and 2006. After initial haemodynamic support, all patients received selective embolization of branches of the hepatic artery. The primary outcome was effectiveness in stopping the bleeding. Secondary outcomes were complications and changes in tumour size after embolization. RESULTS: A single embolization brought haemorrhaging under control in ten patients; one patient needed three embolizations. None of the patients required emergency surgery. In the follow-up of 19 (range 7-49) months, no general or hepatobiliary complications were observed. All 25 adenomas, including those without signs of haemorrhaging in the same liver lobe, were either smaller or not detectable on computed tomography or magnetic resonance imaging after embolization, with the median diameter decreasing from 7.0 to 2.5 cm (P < 0.001). CONCLUSION: Selective embolization of the hepatic artery is a safe and adequate first approach in the management of patients with haemorrhaging hepatocellular adenomas. Furthermore, arterial embolization reduces the size of adenomas in the liver.

Feasibility of minimally invasive approaches in patients with infected necrotizing pancreatitis.

BACKGROUND: Minimally invasive procedures to treat infected necrotizing pancreatitis (INP) are gaining popularity. The proportion of patients suitable for this approach remains unknown. METHODS: Preoperative computed tomography (CT) scans were reviewed from 106 consecutive patients who had surgery for INP between 2000 and 2003 in 11 Dutch hospitals. Collections related to the pancreas were classified according to their distance from the left abdominal wall. Five radiologists judged 'accessibility' for drain placement and the likelihood that there was a fluid component that would drain ('drainability'). Agreement between radiologists was determined. RESULTS: CT scans of 80 (75 per cent) patients were available (59 men; age range 29-80 years). The median interval between hospital admission and preoperative CT scan was 20 days. In 55 (69 per cent) patients, the lateral border of the collection was less than 5 cm from the left abdominal wall. Placement of a drain was deemed feasible in 67 (84 (range 77-89) per cent) patients; mean(s.d.) kappa 0.428(0.096). In 45 (56 per cent) patients, a drain could be placed through the left retroperitoneum. In 43 (54 (range 49-82) per cent) patients, collections were judged to contain a drainable fluid component. Interobserver agreement on 'drainability' was poor, mean(s.d.) kappa 0.289(0.101). CONCLUSION: Most peripancreatic collections in INP were considered accessible to a minimally invasive approach.

A novel technique for auxiliary partial liver transplantation with reno-portal anastomosis and avoidance of the hepatoduodenal ligament.

Auxiliary liver transplantation (ALT) is a treatment for acute liver failure when regeneration of the native liver is possible or for metabolic disorders. In selected cases ALT and orthotopic liver transplantation (OLT) have similar survival when ALT is performed in the orthotopic position (auxiliary partial orthotopic liver transplantation, APOLT). Drawback of ALT with portal vein to portal vein anastomosis is the frequent occurrence of thrombosis, compromising both graft and native liver, and the necessity of a significant resection. To avoid division of portal flow we performed ALT with an end-to-end anastomosis between the graft portal vein and the left renal vein of the recipient (reno-portal ALT, REPALT). The hepatic artery was anastomosed to the aorta using an iliac arterial graft conduit. The bile duct was anastomosed to the stomach. In the two cases presented here excellent immediate graft function occurred with rapid regeneration of the graft and without early vascular complications.

Porcine islet cells of Langerhans are destroyed by human complement and not by antibody-dependent cell-mediated mechanisms.

In the near future, xenotransplantation of porcine islets of Langerhans might be an alternative in the treatment of patients with diabetes mellitus. However, xenotransplantation of islets of Langerhans in large animals has been shown to result in an exceedingly short graft survival, which suggests that a humoral immune response might play a major role in islet demise. This study was performed to assess binding human preformed antibodies to isolated porcine islet cells (PIC) and to determine the lysis of PIC using human sera in complement-mediated cytotoxicity (CMC) and antibody-dependent cell-mediated cytotoxicity (ADCC) assays. Ten Dutch Landrace pigs were used for the isolation of PIC. Sera from 30 healthy blood donors (1/10 diluted) were used in a 51Cr release assay to assess CMC. Heat-inactivated normal human sera and fresh sera from patients with agammaglobulinemia were used as controls. Binding of human IgM IgG, and IgA antibodies to PIC was tested in an ELISA using isotype-specific secondary monoclonal antibodies ADCC was tested in a 51Cr release assay using normal human sera and sera from newly diagnosed type I diabetics with peripheral blood mononuclear cells as effector cells and PIC as targets. It was found that PIC were recognized by human IgM and IgG preformed antibodies and that fresh human sera had strong CMC activity inducing a percentage-specific PIC lysis of 61 +/- 10% (mean +/- SD) within 60 min. Agammaglobulinemic sera killed 42 +/- 12% of PIC. No significant cytotoxic activity was found in ADCC assays using normal sera or sera from diabetic patients. These results show that all tested human sera lyse PIC via CMC, even in the absence of human antibodies, as concluded from the use of agammaglobulinemic sera. In pig-to-human transplantation, islets may be hyperacutely rejected by antibody-dependent and antibody-independent activation of complement and not by antibody-dependent cell-mediated mechanisms.

Human complement activation via the alternative pathway on porcine endothelium initiated by IgA antibodies.

The role of the classical pathway (CP) and the alternative pathway (AP) of complement activation in hyperacute xenograft rejection remains a matter of considerable debate. In addition, it is unknown whether IgG and IgA antibodies activate complement, although these antibodies have been found in hyperacutely rejected xenografts. This study was initiated to assess a possible role of the AP of complement activation in a pig-to-human transplantation model using fresh human sera and isolated antibodies with cultured porcine endothelial cells (PEC) as targets. IgM, IgG, monomeric IgA, and dimeric IgA (dIgA) antibodies with reactivity toward PEC as determined by ELISA were isolated from pooled normal human sera. Serum from patients with agammaglobulinemia was used as a source of human complement. C3 and C4 deposition on nonfixed PEC during CP (1% serum) or AP activation (10% serum with MgEGTA) was analyzed using an ELISA. Complement-mediated PEC lysis was tested in a 51Cr release assay. Using normal human sera as the source of antibodies and complement, C3 and C4 deposition was already found after 10 min of incubation in the CP, whereas an increasing amount of C3 was found in the AP. During AP activation, no C4 deposition was observed, indicating that CP activation did not contribute to the observed AP-mediated C3 deposition. Moreover, dIgA antibodies caused deposition of C3 and not C4. Purified IgM and dIgA antibodies (1 mg/ml) in the presence of 10% agammaglobulinemic serum showed a mean specific PEC lysis of 31% and 28%, respectively. Agammaglobulinemic serum alone or with IgG or monomeric IgA antibodies had no detectable lytic activity. In conclusion, dIgA antibodies might play an additional role in pig-to-human xenograft rejection by activating human complement via the AP.