Pancreaticoduodenal Allografts Research Articles

Intercellular Adhesion Molecular-1, Fas, and Fas Ligand as Diagnostic Biomarkers for Acute Allograft Rejection of Pancreaticoduodenal Transplantation in Pigs

The early diagnosis of pancreas allograft dysfunction is crucial for the management and long-term survival of transplanted pancreases. We investigated whether intercellular adhesion molecular-1 (ICAM-1), Fas, and Fas ligand (FasL) can be used as novel biomarkers of acute pancreaticoduodenal allograft dysfunction in pigs. Forty outbred landraces were randomly divided into three groups. In the control group (8 pigs), a sham operation was performed but no drugs were administered. In groups 1 and 2 (8 pairs each), pancreaticoduodenal transplantation was performed, with the latter administered immunosuppressive drugs and the former not administered drugs. The expression of ICAM-1, Fas, and FasL mRNA in the peripheral vein blood was assessed by flow cytometry and RT-PCR, pre-transplant and on days 1, 3, 5, and 7 after transplantation. Simultaneously, the levels of glucose, insulin, and glucagon in the serum of the recipients were evaluated. The allograft pancreas tissue was obtained to assess the pathological damage and the expression of Fas and FasL by immunohistochemistry. On the first 7 days after transplantation, ICAM-1, Fas, and FasL mRNA expression in the blood leukocytes of the recipient increased significantly in groups 1 and 2 compared with the control group (P < 0.01). However, the levels in group 2 were significantly lower than those in group 1 (P < 0.05). Interestingly, the FasL expression increased but the Fas expression decreased gradually in the graft pancreas tissue during the first week after transplantation in both groups 1 and 2 compared with the control group (P < 0.05). The levels of serous glucose, insulin, and glucagon in groups 1 and 2 obviously changed on day 1 after transplantation but returned to normal on day 2. The recipient's pancreas pathological sections did not exhibit any rejection changes on days 1 and 3 after transplantation but showed rejection damage on days 5 and 7. ICAM-1, Fas, and FasL were found to be sensitive biomarkers of acute pancreas allograft dysfunction after pancreaticoduodenal transplantation in pigs, and their monitoring could be used to evaluate the effectiveness of the immunosuppression therapy.

Arteriojejunal Fistula Presenting with Recurrent Obscure GI Hemorrhage in a Patient with a Failed Pancreas Allograft

We present a case of a patient with a failed pancreaticoduodenal allograft with exocrine enteric-drainage who developed catastrophic gastrointestinal (GI) hemorrhage. Over the course of a week, she presented with recurrent GI bleeds of obscure etiology. Multiple esophago-gastro-duodenoscopic (EGD) and colonoscopic evaluations failed to reveal the source of the hemorrhage. A capsule endoscopy and a technetium-labeled red blood cells (RBC) imaging study were similarly unrevealing for source of bleeding. She subsequently developed hemorrhagic shock requiring emergent superior mesenteric arteriography. Run off images revealed an external iliac artery aneurysm with fistulization into the jejunum. Coiled embolization was attempted but abandoned because of hemodynamic instability. Deployment of a covered endovascular stent into the right external iliac artery over the fistula site resulted in immediate hemodynamic stabilization. A high index of suspicion for arterioenteric fistulae is needed for diagnosis of this uncommon but eminently treatable form of GI hemorrhage in this patient population.

Development of donor-specific immunoregulatory T-cells after local CTLA4Ig gene transfer to pancreatic allograft.

CTLA4Ig gene transfer directly to graft tissue might have the potential to avoid the need for systemic immunosuppression. In our previous studies of bio-breeding (BB) rats, local adenovirus-mediated CTLA4Ig gene transfer protected the pancreas from autoimmune and alloimmune responses. This study investigated the potency of local CD28/B7 costimulatory blockade for induction of donor-specific tolerance and further examined the existing mechanisms. Brown Norway (BN; RT1)-pancreaticoduodenal grafts transfected with Ad.CTLA4Ig via intraarterial ex vivo perfusion were transplanted into streptozotocin-induced diabetic Lewis (LEW; RT1) rats. Ad.CTLA4Ig transduced grafts combined with a short course of FK506 resulted in indefinitely prolonged survival (>156 days vs. 19.5 days with FK506 alone). CTLA4Ig was predominantly expressed in grafts on day 4. The expression was gradually diminished and was only slightly detectable at day >100. The proliferative responses against BN antigen were remarkably enhanced among recipients with rejected grafts, but the T-cells from tolerant recipients (>100 days) showed poor cytotoxic responses. On adoptive transfer assay, the splenic T-cells of tolerant recipients were able to suppress the rejection of BN, but not third-party Wistar Furth (WF; RT1) hearts in irradiated (480 cGy) LEW recipients. The percentage of CD4CD25 splenic T-cells was significantly increased in tolerant recipients (13.53 +/- 4.06% vs. 6.06 +/- 0.56% in naive rats). CTLA4Ig gene transfer to the pancreaticoduodenal allograft combined with a short course of FK506 induces donor-specific tolerance. The mechanism of maintaining tolerance could be explained by development of splenic T suppressor cells.

Duodenal histology for monitoring treatment of acute rejection in pancreaticoduodenal allografts in rats.

Although the value of duodenal histology as a means to diagnose acute rejection in pancreaticoduodenal allografts has been validated, it is not known how the duodenum responds to antirejection treatment in comparison with the pancreas. Diabetic Lewis rats received a pancreaticoduodenal allograft. Cyclosporine was given for 5 days and then discontinued for 2 days (group 1), for 4 days (group 2), for 6 days (group 3), for 8 days (group 4), for 9 days (group 5), and for 10 days (group 6). Two animals of each group were killed for histology at the end of immunosuppressive-free intervals. In the remaining rats, rejection was treated with methylprednisolone on 3 consecutive days. Duodenal histology was compared with pancreatic morphology before and after treatment of rejection. Duodenal histology had a positive and negative predictive value of 100% for detection of acute rejection in the pancreatic portion of the graft. After antirejection treatment, duodenal morphology was however less accurate (positive predictive value, 96%; negative predictive value, 67%). The Spearman correlation coefficient (p) of duodenal and pancreatic rejection grades was higher before antirejection treatment (p=1.0) than thereafter (p=0.724). Considering interstitial and vascular changes separately, vascular rejection correlated to a higher extent than interstitial rejection between the two portions of the graft (p=0.725 vs. p=0.677). Duodenal histology accurately predicts the initial diagnosis of rejection of the pancreas. However, after treatment of acute rejection, duodenal morphology is more likely to recover from rejection than the pancreas. Awareness of this phenomenon might be important for the interpretation of duodenal follow-up biopsies.

Simultaneous pancreas-kidney and pancreas transplantation.

The discovery of insulin in 1922 changed the treatment of type 1 diabetes mellitus (DM) forever. Insulin was the first effective therapy for type 1 DM; however, its success engendered a terrible paradox for patients with this disease. The use of insulin transformed type 1 DM from a rapidly fatal

Beneficial Immunosuppressive Effect of FTY720 Combined With Intrathymic Injection of Splenic Cells on Rat Pancreaticoduodenal Allograft

Beneficial Immunosuppressive Effect of FTY720 Combined With Intrathymic Injection of Splenic Cells on Rat Pancreaticoduodenal Allograft

Liposoluble antioxidants are not consumed in the pancreas after reperfusion in human simultaneous pancreas-kidney transplantation.

There is considerable evidence that under experimental conditions, oxygen free radicals (OFRs) are decisive in the pathogenesis of ischemia-reperfusion injury. Normally OFRs are scavenged by antioxidants such as alpha-tocopherol. Thus, in the following study we investigated whether antioxidants are consumed locally in human pancreatic grafts after reperfusion. A series of ten patients receiving bladder-drained pancreaticoduodenal and renal allografts were studied. Sequential blood samples were drawn locally from the venous outflow of the graft and simultaneously from the radial artery after reperfusion. alpha-Tocopherol, retinol, lycopene, and alpha- and beta-carotene levels were determined. After reperfusion these levels remained largely unchanged. Hence, in our study a consumption of antioxidants locally in the pancreatic graft after transplantation was not demonstrated. Therefore, the antioxidant capacity seems not to be exhausted at that time. This suggests that in clinical pancreatic transplantation oxidant stress in the initial reperfusion period might not have the relevance suggested by animal models.

A technique for vascular reconstruction of pancreaticoduodenal allograft. A literature review and case report

Abstract In most cases, whole pancreaticoduodenal allograft vessels can be reconstructed using a segment of donor common iliac artery bifurcation. An alternative way to bridge the splenic artery and the superior mesenteric artery (SMA) is to use a short segment of distal SMA as an interposition graft, as described herein.

Exocrine pancreatic proteins in serum during pancreatic allograft rejection.

The serum concentrations of immunoreactive pancreatic secretory trypsin inhibitor, cationic elastase, anionic trypsin, cationic trypsin, and total amylase activity, were studied after pancreatic allograft transplantation. Nine patients received whole organ pancreaticoduodenal allografts with exocrine drainage to the bladder. Eight of the patients received simultaneously a renal allograft. The serum concentration of immunoreactive cationic elastase increased gradually during the first postoperative days to a peak on the fifth day after surgery; all other proteins decreased in concentration after the first day. Eighteen episodes of pancreatic and/or kidney rejection, diagnosed by means of kidney biopsy, urinary cytology, kidney function, and urinary amylase levels, were analyzed. The pancreatic proteins displayed different patterns in serum concentration during the days immediately before diagnosis of rejection. The pancreatic secretory trypsin inhibitor showed the most pronounced peak in serum concentration during rejection and even reacted during some episodes without a decline in urinary amylase output. Cationic elastase on the other hand showed no reaction at all. From this homogeneous material it is possible to conclude that changes in serum concentrations during rejection are not the same for all pancreatic exocrine proteins.

Reperfusion of Duodenum and Pancreas Following 24 hr of Cold Storage in Perfadex or UW Solution

We have studied the immediate reperfusion and the graft outcome of the duodenum and pancreas separately in a porcine whole-organ pancreaticoduodenal allograft transplantation model using 24 hr of cold storage. Of 19 transplantations, 12 grafts were perfused and stored in Perfadex and 7 in University of Wisconsin (UW) solution. The organ weights before and after storage were determined in 6 grafts stored in Perfadex and 6 grafts stored in UW solution in order to quantify the degree of dehydration of the graft during storage. In 6 of the grafts perfused with Perfadex, a hyperosmotic salt dextran-containing solution (HSD) was perfused into the graft aorta at reperfusion. Duodenal reperfusion and reperfusion injury were studied by measuring mucosal pH (pHi) and by microscopic examination, respectively. Pancreatic reperfusion was studied by scoring the macroscopic appearance and microscopic examination. Daily blood glucose was used to determine the endocrine function and a secretin-chole-cystokinin stimulation test was performed on the second postoperative day to evaluate the exocrine function. All duodenal grafts except 1 in the UW group showed a sufficient reperfusion according to pHi and all had microscopic changes suggesting a moderate reper fusion injury. The macroscopic appearance of pancreas was significantly worse in the UW group than in the two Perfadex groups, Only 1 of 7 grafts in the UW group showed signs of endocrine function on the first postoperative day compared with 11 of 12 in the Perfadex groups. Our data suggest that the porcine duodenum can be cold stored in both Perfadex and UW solution for 24 hr but the pancreas does not survive cold storage in UW solution for 24 hr. Weight loss during storage was more marked in grafts stored in UW solution, indicating that dehydration may be one explanation for the decreased viability of these grafts. Similarly duodenal reperfusion in all groups makes technical failure a highly unlikely explanation for the differences in outcome of the pancreatic grafts.

Protease activation following reperfusion of porcine pancreatic allografts

To study the degree of protease activation at reperfusion of a pancreatic allograft after cold storage for 24 hr, 18 porcine whole-organ pancreaticoduodenal allograft transplantations were performed. Twelve grafts were flushed with and stored in Perfadex. In six of these, a hyperosmotic salt solution was injected into the graft aorta at reperfusion. Six grafts were flushed and stored in UW solution. Eleven of twelve grafts in the Perfadex groups were functioning on the first postoperative day, compared with one of six in the UW solution group. There was a significantly more pronounced protease activation among grafts stored in UW solution than in the other groups, with a subsequent breakthrough of the local protease protection barrier made up of protease inhibitors. In surviving pigs ( n = 14), biochemical signs of protease activation evolved in plasma, including formation of trypsin-protease inhibitor complexes, a decline in C3 and kininogen levels, and a decline in functionally active α 2-macroglobulin, functionally active antithrombin III, and plasma kallikrein inhibitory activity. These biochemical signs of pancreatitis correlated with a deteriorated graft function on the second postoperative day, indicating that graft tissue damage occurred due to protease activation.

DUODENAL MUCOSAL pH AS A REPERFUSION INDICATOR IN PANCREATIC-DUODENAL TRANSPLANTATION IN THE PIG

We have studied differences in reperfusion between the pancreas and the duodenum after 6 hr of cold storage in a porcine whole-organ pancreaticoduodenal allograft transplantation model. Two different flush-out and storage solutions, Perfadex and EuroCollins, were compared. Graft duodenal mucosal pH (pHi) was measured as an indicator of duodenal mucosal reperfusion. Pancreatic reperfusion was estimated indirectly using a ratio between the release of immunoreactive cationic trypsin (irCT) to serum 10 and 60 min following reperfusion. Twelve pigs (Perfadex n = 6, EuroCollins n = 6) were transplanted and all showed preserved endocrine and exocrine function postoperatively. Our data support the concept that reperfusion of a pancreaticoduodenal graft can be estimated using duodenal pHi and that the ratio of irCT at 10 and 60 min gives an indirect estimate of pancreatic reperfusion. The results also show that grafts stored in EuroCollins reperfuse more slowly than grafts stored in Perfadex.

Ex vivo perfusion of canine pancreaticoduodenal allografts using class-II-specific monoclonal antibody delays the onset of acute rejection.

In the following study, we investigated whether ex vivo perfusion of canine pancreaticoduodenal allografts prior to transplantation using a class-II-specific monoclonal antibody (MoAb) OKIa1) could prevent acute rejection. Untreated grafts were rejected within 6 days after transplantation, and all of these recipients suffered severe hyperglycemia. In contrast, in recipients who received grafts which underwent ex vivo class-II-specific MoAb perfusion treatment, the mean urinary amylase levels were sustained significantly higher (11,733 +/- 4493 vs. 3274 +/- 2108 U/L on day 7, P < 0.005), and mean fasting blood glucose (FBG) levels remained within the normal range (13.4 +/- 5.8 vs. 23.4 +/- 3.9 mM on day 7, P < 0.0005). Low doses of cyclosporin A (CsA) were necessary in order to maintain lower FBG levels. Histopathology analysis on day 7 after transplantation showed that endotheliitis and necrosis were much less prominent in the MoAb-treated grafts. In the light of our results, we conclude that ex vivo perfusion of canine pancreaticoduodenal allografts using a class-II-specific MoAb is effective in delaying the onset of acute rejection, and low doses of CsA could extend this effect.

Ex vivo perfusion of canine pancreaticoduodenal allografts using class-II-specific monoclonal antibody delays the onset of acute rejection

In the following study, we investigated whether ex vivo perfusion of canine pancreaticoduodenal allografts prior to transplantation using a class-II-specific monoclonal antibody (MoAb) OKIa1) could prevent acute rejection. Untreated grafts were rejected within 6 days after transplantation, and all of these recipients suffered severe hyperglycemia. In contrast, in recipients who received grafts which underwent ex vivo class-II-specific MoAb perfusion treatment, the mean urinary amylase levels were sustained significantly higher (11733 ± 4493 vs. 3274 ± 2108 U/L on day 7, P < 0.005), and mean fasting blood glucose (FBG) levels remained within the normal range (13.4 ± 5.8 vs. 23.4 ± 3.9 mM on day 7, P < 0.0005). Low doses of cyclosporin A (CsA) were necessary in order to maintain lower FBG levels. Histopathology analysis on day 7 after transplantation showed that endotheliitis and necrosis were much less prominent in the MoAb-treated grafts. In the light of our results, we conclude that ex vivo perfusion of canine pancreaticoduodenal allografts using a class-II-specific MoAb is effective in delaying the onset of acute rejection, and low doses of CsA could extend this effect.

Apoptosis in pancreatic allograft rejection —ultrastructural observations

Transplantation of pancreaticoduodenal allografts in the PVG.RT1c----PVG.RT1u high responder rat strain combination led to the evolution of haemorrhagic pancreatic necrosis over a rejection course of 8d. A cellular infiltrate consisting mainly of monocytes and macrophages was detectable in the stroma while acinar cells showed degranulation and a progressive decrease in number. From day 4 on apoptotic bodies could be identified ultrastructurally within the exocrine tissue. Apoptosis during pancreas rejection, previously undescribed, contributes to acinar cell loss after transplantation in this model.

Pancreas Transplantation at Mayo: III. Multidisciplinary Management

Although pancreas transplantation is a complicated procedure, a good level of success has been achieved because of the introduction of cyclosporine for immunosuppression, improved methods for diagnosing rejection, and a multidisciplinary approach to management. Our immunosuppressive regimen was quadruple therapy with induction by using Minnesota antilymphoblastic globulin. A biopsy technique was instituted in which the pancreas specimens were obtained under cystoscopic direction during episodes of hypoamylasuria. The criteria for rejection episodes were not only biochemical abnormalities but also histologic confirmation and a follow-up to exclude other causes of graft dysfunction. Infectious disease management included use of oral selective bowel decontamination for 3 weeks after transplantation. At the Mayo Clinic between October 1987 and December 1988, 16 patients received pancreaticoduodenal allografts (both kidney and pancreas in 13 and pancreas only in 3 after a prior successful kidney transplantation). In two pancreas and one kidney allograft, function was lost. One patient died of multiorgan failure. The cystoscopically directed biopsy technique was performed 23 times with minimal complications and a 93% success rate. The metabolic results have been excellent; the glycosylated hemoglobulin level was normal 3 to 6 months after transplantation. The quality of life was significantly improved in almost all patients. Nutritional assessment revealed little deterioration after transplantation. With a multidisciplinary approach, the needed answers about the effect of pancreas transplantation on the degenerative complications of diabetes should be forthcoming.

EVIDENCE THAT THE SOLUBLE INTERLEUKIN 2 RECEPTOR LEVEL MAY DETERMINE THE OPTIMAL TIME FOR CYSTOSCOPICALLY-DIRECTED BIOPSY IN PANCREATICODUODENAL ALLOGRAFT RECIPIENTS

In 18 consecutive pancreaticoduodenal allograft recipients (15 combined kidney/pancreas and 3 pancreas only after a prior successful kidney transplantation) operated on between December 1987 and February 1989, we studied the soluble interleukin 2 receptor (SIL-2R) level over time. All pancreaticoduodenal allografts were transplanted with exocrine drainage via a duodenocystostomy that allowed for cystoscopically directed needle biopsies of the pancreas. Of these 18 recipients, at 6 weeks after transplantation, 6 had had no rejection episodes or cytomegalovirus disease (control group), an acute allograft rejection had developed in 7, CMV disease developed in 4, and both rejection and CMV disease developed in 1 by 12 days after transplantation. SIL-2R level increased in all patients during immunosuppressive induction therapy (preoperative mean +/- SE, 1637 +/- 284 U/mL; maximum, 4367 +/- 687 U/mL). After induction therapy, the mean was 2768 +/- 432 U/mL. In all 6 recipients in the control group, SIL-2R level continued to decrease. However, SIL-2R level was significantly higher compared with controls, in those who had CMV disease (levels were increased at a mean of 7 days before diagnosis of CMV disease) and in those who had acute rejection episodes (levels were increased a mean of 7 days before the clinical diagnosis of rejection). Factors that did not cause an increase in SIL-2R level included acute pancreatitis, wound infection, operative procedures, and CsA nephrotoxicity. SIL-2R level can be useful for monitoring pancreaticoduodenal allograft recipients. Increases predict impending rejection or CMV disease, prior to the onset of organ dysfunction. When SIL-2R level increases, we recommend cultures of blood and urine to exclude CMV and pancreaticoduodenal allograft biopsy to confirm early rejection prior to the initiation of potentially dangerous antirejection therapy.

Sequential histopathologic changes in pancreaticoduodenal allograft rejection in dogs.

To determine the nature and sequence of the histologic changes in the early rejection of pancreaticoduodenal allografts and to assess the correlation between pancreaticoduodenal biopsy findings and the pathologic changes in the graft, we performed serial cystoscopically directed needle biopsies of pancreaticoduodenal allografts in 18 dogs and compared the findings with the histologic changes in 16 autografts as controls. Tissue adequate for evaluation was obtained by the biopsy technique in 70% of instances. The earliest and most characteristic manifestation of rejection was diffuse mixed inflammatory infiltrates involving the pancreatic acinar tissue and duodenum. The biopsy findings correlated well with the changes in the resected pancreatic specimens. Cellular rejection in the duodenum correlated with rejection in the pancreatic graft. There were no changes in the autografts that resembled cellular rejection. We conclude that, in the canine model, cystoscopically directed needle biopsy of pancreaticoduodenal allografts consistently provides adequate tissue for the diagnosis of rejection; the status of the graft can be monitored by serial biopsies of pancreatic acinar tissue and, possibly, by serial biopsies of the duodenal wall alone.

Long-term studies of pancreas allotransplantation in experimental diabetes mellitus.

Pancreaticoduodenal (PD) allografts (Brown Norway-alloxan-diabetic rats, n = 190) were treated with cyclosporin A (Cy-A) 10 mg/kg/daily and compared with nondiabetics with Cy-A treatment (n = 55), diabetics (n = 50), and diabetics with Cy-A treatment (n = 45). Body weight, blood sugar, blood insulin, blood urea nitrogen (BUN), and creatinine were monitored periodically; there were marked elevations of BUN and creatinine levels, indicating probably nephrotoxicity of Cy-A at this dosage. Some islet cell atrophy in the PD allografts was noted at the conclusion of the study. With respect to the immunosuppressive effect of Cy-A in alloxan diabetic rats, Brown Norway PD transplants into Lewis rats were successful and free of rejection for as long as 15 months post-transplantation. The body weight of these PD transplanted rats, however, never approached values representative of the nondiabetic rats. In our experience, the PD allograft model is acceptable in the clinical situation, particularly in children if the microsurgical technique is mastered and if the Cy-A regimen is used in combination with other immunosuppressant(s).

Effects of pancreaticoduodenal allografts on diabetic testicular lesions in the rat

AbstractAbnormal testicular histology is common in untreated diabetic animals and men. Reversal of testicular lesions with return of function and fertility are seen in controlled diabetes. We investigated the effects of pancreaticoduodenal (PD) allografts on testicular lesions of alloxan‐induced diabetic rats. For periods of l to 15 months, 190 diabetic Lewis rats were allowed to remain diabetic before receiving PD transplants and Cyclosporin A (CsA); 190 other rats were divided into 4 control groups: normal rats with and without CsA, and diabetic rats with and without CsA. Following transplantation, transplanted rats and corresponding controls were sacrificed at 3‐month intervals. Testicles were morphometrically examined. CsA did not affect rat testicular histology. All successfully transplanted rats (n = 97) had complete reversal of hyperglycemia. In the first 6 months following transplantation, the testicular lesions appear to worsen; thereafter, the testicular sizes, tubular densities, and percentages of germinal tissue converge toward nondiabetic levels. This convergence was more marked in the later transplantation groups (≥ 9 months of diabetes before receiving transplantation) than in the earlier groups (&lt;9 months). Overall, these results suggest that PD transplantation may partially reverse testicular lesions. Although pancreas transplantation may initially worsen diabetic testicular lesions, after 6 months, improvement of the lesions can be expected. Thus, an important result from this study relating to the clinical laboratory is that good control of the blood glucose in diabetics causes reversal of diabetic testicular lesions with return of function and fertility. In addition, Cyclosporin levels should be monitored in clinical laboratories in transplant patients to prevent toxic injury to the kidney and liver. However, Cyclosporin did not damage the testis in our study.