A Study Of The Model Establishment For Pancreas Transplantation In Miniature Swine And Monitoring Of The Early Acute Rejection Of Pancreatic Allotransplantation

Objective: The syndrome of insulin-dependent diabetes mellitus (IDDM) includes not only abnormal glucose metabolism but also specific microvascular complications that include nephropathy, retinopathy and neuropathy. In the short term, improvement in the quality of life and possible prevention of further morbidity associated with diabetes makes pancreas transplantation an important therapeutic option, particularly when combined with a kidney transplant, in appropriately selected diabetic patients. The focus of the early management of the pancreas transplant recipient is the prevention of acute rejection. Recipients of pancreas allografts are routinely monitored by clinical and biochemical markers that include ultrasound and imaging of the pancreas, serum levels of amylase, lipase, blood glucose, C-peptide, and immunosuppressive drug levels and measurement of urinary amylase for bladder-drained grafts. The specificity of many of these tests is rather low, with a predictive value for acute rejection generally around 50% to 75%. Biopsies of pancreatic allografts remain the most specific marker for acute rejection of the pancreas and help explain other reasons for pancreatic dysfunction. The purpose of this study is to establish a model for pancreas transplantation in miniature swine so as to monitor the earlier acute rejection by ultrasound-guided percutaneous pancreatic allograft biopsy and histopathologic examination. To investigate the histopathological changes, the expression of CD25+ in mononeuclear cells infiltrating in the pancreatic parenchyma allografts was observed dynamically and the diagnostic significance at the early stage of acute rejection was analyzed as well.We explored the roles and significance of the immunological indexes such as CD25+, perforin expression level in peripheral blood mononuclear cell, serum levels of IL-2 and IL-4 in early acute rejection after pancreas transplantation by means of dynamically monitoring the changes of the above-mentioned indexes to provide theoretical proof for clinical diagnosis of the early acute rejection due to pancreas transplantation.Methods: (1) A total of 40 miniature swine were divided into donors and recipients randomly and animal model was established with pancreas transplantation that was similarto protocols of the clinical transplantation technique. The total pancreas with a shortsegment of duodenum was transplanted to a recipient by anastomosis of vessels to the recipient iliac vessels and small bowel segment to the jejunum with enteric drainage. During recipient operation, mean arterial pressure(MAP), central venous pressure(CVP) were monitored. Liquid supplement, routine anti-coagulation and anti-infection were conducted postoperatively. Meanwhile, the recipients were observed closely and the survival rate of recipients/allografts was calculated in postoperative period. (2) Color Doppler Ultrasonography in the evaluation of blood flow to pancreatic allografts and ultrasound-guided percutaneous pancreas allograft biopsy and histopathologic examination were performed at different time points after pancreas transplantation. (3) The histopathological characteristics were observed and analyzed and the expression of CD25+ in mononuclear cells infiltrating into pancreatic allografts was detected by immunohistochemical staining so as to make sure whether there was infiltration of activated lymphocytes in the pancreatic allografts. (4) The expression levels of CD25+ lymphocytes in mononuclear cells in peripheral blood and perforin were monitored dynamically by mAb-FACS-immunofluorescence technique and concentrations of serum IL-2 and IL-4 at different time points were determined by ELISA.Results: (1) The pancreas transplantation had been performed for 20 times and the successful rate of operation was 90%( 18/20). Recipient's MAP decreased after the reopening of inosculated blood vessels (P<0.05). Adequate transfusion could contribute to successful operation for recipients. Survival 5 days was found in 9 recipients and allografts and su...