Comparison of graft morphology and endocrine function after vascularized whole-pancrease transplantation in the rat by different surgical techniques

Induction of heme oxygenase-1 improves the survival of pancreas grafts by prevention of pancreatitis after transplantation

BACKGROUND

Ischemia/reperfusion (I/R) injury after pancreas transplantation might result in graft pancreatitis. The role of heme oxygenase-1 (HO-1) in pancreas transplantation and prevention of graft pancreatitis is unknown.

METHOD

We studied the impact of HO-1 induction with cobalt protoporphyrin (CoPP) in experimental pancreas transplantation with moderate (6 hr) and prolonged (20 hr) cold ischemic time (CIT). Donor animals received CoPP 5 mg/kg intraperitoneal at 48 hr or intraperitoneal saline injections in the corresponding control groups before procurement. Harvested grafts were perfused with HTK solution and stored at 4 degrees C.

RESULTS

After prolonged CIT, graft survival was 100% with CoPP pretreatment in contrast to only 37.5% without pretreatment. CoPP-pretreated grafts demonstrated an unimpaired endocrine graft function at moderate and prolonged CIT. Serum lipase activity as a sign of exocrine preservation was significantly lower. In addition, morphological architecture was well preserved. CoPP pretreatment markedly increased HO-1 gene expression in donor pancreas (130-fold increase) by means of quantitative reverse transcriptase -polymerase chain reaction. Immunohistochemical examinations showed that the increase of HO-1 on the protein level was related to HO-1-positive donor macrophages in the pancreas grafts. HO-1 overexpression was accompanied by significant decrease of proinflammatory cytokines such as tumor necrosis factor-alpha, interleukin (IL)-2, IL-6, interferon-y, and by significant increase of the anti-inflammatory cytokine IL-10 and less expression of adhesion molecules such as e- and p-selectins.

CONCLUSIONS

HO-1 is highly inducible in the allograft rat pancreas and associated with a survival benefit and good graft function after transplantation. This study contributes to the beneficial potentials of HO-1 for the prevention of graft pancreatitis.

The anatomical study on the rat pancreas and its ducts with emphasis on the surgical approach

It was intended to present information about the anatomy of the pancreas and especially to emphasize the variation of pancreatic ducts in the rat, which may guide researchers in experimental studies. In 27 adult rats, latex dye was introduced into the biliopancreatic duct, portal vein and arteries. The pancreas with the neighboring structures was studied with the aid of the dissection microscope and measurements were by means of micrometric ocular. The pancreas was divided into three parts i.e. the biliary, duodenal and gastrosplenic portions. The biliopancreatic and pancreatic ducts as well as biliary and duodenal portions of the pancreas could be seen ventrally with a minor procedure such as pulling the duodenum caudally, and additionally the entire pancreas and its ducts could also be reached dorsally since the stomach was turned cranially with the duodenum. The biliopancreatic duct diameter and length of the ducts were 1.01+/-0.03 and 28.86+/-0.59 mm, respectively. The anterior pancreatic duct originated from the biliopancreatic duct on different sides, 17.96+/-0.75mm away from the duodenal papilla. The anterior pancreatic duct drained the gastrosplenic portion of the rat pancreas and this duct, via the duodenal duct, partially collected secretion of the duodenal portion at a ratio of 74.07%. The posterior pancreatic duct opened to the biliopancreatic duct and its distance from papilla duodeni was changed from 0 to 8 mm. When the biliopancreatic duct is ligated at the level of the duodenal opening, the posterior pancreatic duct or a small duct from duodenal portion should be taken into consideration because these ducts opened to biliopancreatic duct at the level of papilla duodeni at a ratio of 37.04%. In conclusion, the duct system of pancreas had a great variation and therefore the success rate of the surgery could be increased when surgeons have more knowledge on variations of the duct system in this region.

Model of mouse pancreaticoduodenal transplantation

Our technical procedure for mouse pancreaticoduodenal transplantation is described. A number of methods were attempted. Among them, a modification of S. Lee's method was thought to be the most successful procedure, which was performed with end-to-side anastomosis of the donor portal vein to the inferior vena cava and that of the donor aortic patch to the aorta. Even with this method, however, arterial thrombosis or venous stenosis of the anastomoses was inevitable without the use of some devices as well as special skills in microsurgery.

Experimental rat pancreas transplant: surgical technique and immunological considerations

Vascularized whole pancreas transplantation in the rat was performed on the abdomen using a cuff technique for vascular anastomoses. Two different exocrine drainage procedures, either intestinal or ureter drainage, were used. In the isograft transplant models, hyperglycemia was ameliorated immediately after transplantation and all of the grafts functioned during the observation period. In the allograft transplant models without immunosuppression, graft rejection, as defined by recurrence of hyperglycemia (blood glucose > 200 mg/dl) occurred 6-9 days post-transplant. Allograft rejection could be delayed approximately 1 month after transplant with short-term use of FK506. These different models, using either intestinal or ureter exocrine drainage, are similar to dominant clinical pancreas transplantation with enteric exocrine drainage or urinary tract drainage, respectively. It is thus concluded that whole pancreas transplant with either intestinal or ureter exocrine drainage is an ideal model for physiological and immunological experimental studies in pancreas transplantation.