TRANSPLANTATION OF FETAL PORCINE PANCREAS TO DIABETIC OR NORMOGLYCEMIC NUDE-MICE - EVIDENCE OF A RAPID ENGRAFTMENT PROCESS DEMONSTRATED BY BLOOD FLOW AND HEAT SHOCK PROTEIN-70 MEASUREMENTS

The aims of the present investigation were to study the blood flow rat e in transplanted fetal porcine islet-like cell clusters (ICC) with la ser-Doppler flownmetry and to evaluate the influence of hyperglycemia on this process. In order to investigate the degree of stress in trans planted beta cells during engraftment, the amount of heat shock protei ns (HSP) or stress proteins was measured, ICC were prepared from the f etal porcine pancreas by employing a tissue culture technique. A total volume of 6 mu l (-750) ICC was transplanted under the left kidney ca psule of either normo- or hyperglycemic C57BL/6J nude mice, The blood flow to the xenogeneic islet graft and the adjacent kidney parenchyma were measured with laser Doppler flowmetry (LDF), Within 2 hr after tr ansplantation (day 0) or 3, 6, 9, 12 (both normo- and hyperglycemic re cipients), 15, 40, or 85 (only normoglycemic recipients) days after im plantation of ICC into the nude mice, the hsp70 contents of the grafts were analyzed by means of an immunoassay, Revascularization of the su bcapsular ICC graft was initiated rapidly, and 3 days posttransplantat ion the nutritional blood supply constituted 70% of the adjacent kidne y blood flow, This figure increased with time after implantation until the IGC graft had equal or even higher blood perfusion than the adjac ent kidney parenchyma, Hyperglycemia in recipients did not affect the revascularization process, Hsp analysis from ICC in culture demonstrat ed a surprisingly high content of hsp70, However, 3-9 days after trans plantation the hsp70 content was markedly reduced in both the normo- a nd hyperglycemic group and then remained low in both groups. Thus, the present study showed that ICC transplanted into normo- or hyperglycem ic nude mice were rapidly revascularized, and that the production of h sp70 was lowered already 3 days after transplantation when compared wi th cultured ICCs.