Long-term exocrine function of the pancreas transplant

Sequential isologous organ transplantation in inbred rats: pancreaticoduodenal transplants

A total of 847 inbred Lewis rats of mixed sex were used in this pancreaticoduodenal (Pd) donor aging study. Pd grafts were taken from 9- to 12-month-old donors and transplanted into 3-month-old recipients (thus, the first generation Pd graft, or 1 Pd). After 9 to 12 months, the same Pd grafts were again harvested and transplanted into 3-month-old rats (thus the 2 Pd generation). This cycle was repeated to obtain the 3, 4, and 5 Pd series. Sequential transplantation was able to extend the Pd grafts' mean survival time to 32 months for fourteen 4 Pd grafts, and to 39.2 months for four 5 Pd grafts (the longest lived graft survived for 42 months). The pancreas and duodenal sections of the grafts remained normal throughout the entire study. However, the aortic sections of the grafts (which were harvested to include the superior mesenteric and celiac arteries) all exhibited moderate to massive atherosclerotic changes by the 5 Pd mean survival age of 39.2 months. Such histological changes commenced even before 21 months of Pd graft age in some animals, gradually progressing to dilation of the aorta (and subsequent narrowing of aortic tributaries), as well as formation of an eggshell-like inner membrane shielding the aortic intima, by 42 months. Such atherosclerotic changes precluded transplantations beyond the 5 Pd series.

Long-term hormonal secretion from the autotransplanted sheep pancreas

Seventy-five duct-ligated pancreatic segmental autotransplants were made into bipedicled skin loops on the necks of merino ewes by vascular suture to the carotid artery and jugular vein; the in situ pancreatic remnants apparently continued to function normally. Thirty-seven were found to be active hormone secretors (secretion-rate responses to Na butyrate greater than 1 mU/min for insulin or 5 ng/min for glucagon) when first tested approximately 1 month after transplantation; 12 remained active at 1 year, 5 at 2 years, and 4 at 3 years. At first testing, the responses were (mean +/- standard errors): insulin, 12.3 +/- 2.52 mU/min; glucagon, 52.6 +/- 13.5 ng/min. It is concluded that this autotransplant can, on occasion, be relatively long-lived and that it is a useful model with which to study not only pancreatic physiology but also non-immunological factors involved in survival of endocrine function in pancreatic transplants.

Transplantation of preserved pancreatic islets into the portal vein of rats

Langerhans islets were isolated from the exocrine pancreata of Wistar rats by the improved collagenase-digestion method. The isolated islets were preserved in a tissue culture medium for seven days. Transplantation of these preserved islets into the portal vein of streptozotocin-induced diabetic rats resulted in a significant reduction of hyperglycemia, polyuria and glucosuria, and a restoration of weight gain. It was found that these effects could be maintained for 16 weeks. In order to normalize the K-values and plasma insulin levels, at least 600 islets had to be transplanted into each diabetic rat.