Cheung, SSC

Ricordi, C

Starzl, TE

Tai, J

Tze, WJ

Transplantation Proceedings

English

Name not available

FK506 an effective immunosuppressant for islet xenotransplantation

Tze, W. J

Tai, J

Cheung, S.-S. C

Ricordi, C

Starzi, T. E

University of Miami: Scholarship@Miami

FK 506 : an effective immunosuppressant for islet xenotransplantation

D-Scholarship@Pitt

/fK/p~ FK 506: An Effective Immunosuppressant for Islet Xenotransplantation W.J. Tze, J. Tai, S-S.C. Cheung, C. Ricordi, and T.E. Starzl REPLACING the damaged insulin-producing tissue by transplantation of pancreatic islets is considered the most physiological approach to diabetes treatment and has the potential to prevent the development of chronic com-plications. Due to the large number of potential diabetic recipients. it would be impossible to obtain sufficient supply of donor organs to fulfill the demands. One solution to resolve donor organ shortage is the use of xenogeneic pancreatic islets. FK 506. a new immunosuppressive agent. is very effective in rat islet allotransplantation across the major histocompatibility (MHC) barrier. 1.1 Use of this agent in islet xenotransplantation has not been studied extensively. The present study was conducted to determine the efficacy of FK 506 on the survival of human islet xenograft in discordant rats. MATERIALS AND METHODS Human Islets Human islets were isolated from a 12-year-old donor with the automated digestion-filtration methods as described earlier.' Is· lets were then purified with Euro-Collins FicoH gradient in a Cobe 2991 ceil separator. Purified islets were placed in culture medium and transponed from Pittsburgh to Vancouver for xenotransplan· tation. Transplantation and Immunosuppression ~ale ACI rats (Harlan Sprague.Dawley. Indianapolis. Ind) of 200 to 225 g body weight were used as recipients. Human islets stained with dithizone were hand·pickedunder dissection microscope. A total of nine rats were transplanted with 500 human islets each under the left renal capsule. Five transplanted rats received FK 506 (Fujisawa Pharmaceutical Co. Osaka. Japan) treatment at 2 mglkg!d intramuscularly for 2 weeks and then at weekly intervals until they were killed. startinl! immediately after transplantation. The remaining four rats received saline injection. Immunohistochemical Study Rat reCipients of human islet xenografts treated with FK .506 were killed on days 16.36.74, 100. and 124 after transplantation. Equal halves of the kidney containinl! the I!raft were snap frozen in LN2 or fixed in Bouin's fixative. Paraffin sections were stained for insulin. glucagon. and somatostatin with immunoperoxidase stain-ing (ABC stainiDl! kit. VectastaUl. Dimension Laboratories. Mis· ~fssaugaK Ontario/; frozen secuons were stained for cellular 1IUlI'k. ers with monoclonal antibodies against rat leukocyte common antigen. endothelial cell (OX43), class II MHC antigen. and CD4 and CDS lymphocyte subsets (Cedariane Laboratories. Hornby. Ontario I. Perfusion The kidneys containing the islet I!rBft for 36. 74, and 100 days were perfused in vitro to assess the function of the islets before beiDl! processed for immunohistochemistry. The ammal was anesthe-tized with halothane. The abdominal cavity was opened and the renal anery cannulated with a PE60 catheter according to the method of Korsgren et a1: The cannulated kidney was removed and placed in a moist chamber at 31'C. the catheter connected to a peristaltic pump. and the organ perfused at 0.1 mUmin with 31'C MI99 supplemented with 2.5 mmollL HEPES and 0.4% bovine serum albumin and continuously gassed with .5% CO:zl9S% 0z- The experiment started with 60 minutes of perfusion with a medium containing 100 mgldL glucose followed by a ~minute perfusion with medium containing 450 mgldL glucose. and finally 60 minutes with medium containing 100 mgldL glucose. The samples collected were stored at - 2O"C until insulin assay by radioimmunoassay (Pharmacia RIA kit. Pharmacia. Montreal. Quebec). The I!rBft site was divided for histology as described earlier. RESULTS In nonimmunosuppressed rats. by day 5 after xenotrans· plantation nearly all the insulin-containing cells had disap-peared and the bulk of the graft was replaced by fibrotic tissue. Some of the ductal clements were still detected and nonnal in appearance. CD4 and CD8 T·cell subsets had infiltrated the graft tissue. The transplanted kidney with human islet graft removed from an FK 506-treated recipient 16 days after xenotrans· plantation contained human islets that appeared healthy and well vascularized by the host. Insulin-containing cells were present in abundance. In some areas occasional lymphoid cells were seen. Figure 1 shows that the human islet xenograft still contained insulin after 124 days in the xenogeneic rat recipient. The general appearance of the human islets was similar to that of the l6-day specimen. Again. the amount of lymphoid cells in the vicinity of the graft varied with the location. Although both CD4 and CDS cells were present around the graft. they were rarely seen within the islets. Figure 2 shows that the human islets that had survived in xenogeneic recipients responded to glucose stimulation when perfused in situ in the graft bed. Although insulin secretion after glucose challenge was delayed. a distinct increase of insulin response was detected. In contrast. no From the Depar1ment of Pediatrics and Pathology. Universrty of British Columbia. Vancouver, British Columbia. Canada. and De-penment of Surgery. University of Pittsburgh, Pittsburgh. Pennsyl-vania. Address repont requests to W.J. Tze, MD. Department ot Pediatrics. University of British Columbia. Clo BC's Childrens Hospital. 4480 Oak St. Room 1 A40. Vancouver, BC. Canac:la. V6H 3V4. C 1992 by Appleton & Lange 0041·13451921$3.001 +0 Transp4antatJon ProCflfJdiugs. Vol 24. No 6 (December). 1992: pp 284&-2850 2&49 2850 fig 1. An area of human Islet xenograft tissue 124 days after xenotransplantallon under the kidney capsule of an FK 506 (2 mgIkgId for 2 weeks then weekly IM)-treated ACI rat. Lymphoid cells of both C04 and COO subsets are present in the vicinity of the graft. but not within the islets (x 560). insulin was detected in the perfusates from normal control kidneys without islet trnnsplant. DISCUSSION In an earlier report we demonstrated that FK 506 was effective in the prolongation of fresh rat islet allograft across the MHC barrier.! The present findings confirmed that this drug was effective for the marked prolongation of human islet xenognft survival in rat recipients. Despite the presence of lymphoid cell infiltration in some areas, the gnft tissues appeared to be healthy and contained cells with demonstrable insulin and glucagon by immunohisto-chemical stainings up to >4 months after transplantation, when the experiment was terminated. These human islets were also found to be functional as demonstrated by significant insulin response to glucose stimulation in two thirds of the cases. Histologic examination of the graft that did not respond to glucose challenge had many fewer islets in the graft bed than the others, and may account for the poor results. The important finding of this study is that FK 506 alone TZE. TAl. CHEUNG. ET Al 4 E " 3 :::2 = c :s 2 • oS 1 oL-...I.---l--.l_.L---l.---I..-.l_.L-.....J.....---I...---I---J OZ. 1 • 10 12 1. 11 '1 20 22 24 Fraction FIg 2. Insulin concentrallona in ellluent medium collected from hLman islet-bearing kIdneya of FK 506-Immunosuppressed ACI ra1L KIdneys were perfused with medium containing 100 or 450 rl'9'dL glucose as indicated. E~-~F 36 days; (0-0) 1()O.(jay xenograft, E~K mean of n = 4) c:on1rOl kidney without graft tissue. The human islets responded to glucose stimulation. In contrast. no Insulin was detected In the perfusates from normal con1rOI kidneys withoUt islet transplant. and given intermittently was effective in the islet prolon-gation in this discordant xenograft model. In most discor-dant islet xenograft transplantation models. the tissues were rapidly rejected. '.6 The present findings support the view that with the use of a new generation of immunosup-pressive agents. islet xenotrnnsplantation in humans is a future possibility. REFERENCES I. Tze WJ. Tai J. Cheung SSC. et 11: Transplant Proc 23:3200. 1991 2. Yasunami Y. Schinichiroh R. Kamei T: Transplantation 49:682. 1990 3. Ricordi C. l..al:y PEt Finke EH. et 11: Diabetes 37:413. 1988 4. Korsgren O. Jansson L. Andersson A: Diabetes 38:510. 1989 S. Tze WJ. Tai J. Cheung S: Transplantation 49:S02. 1990 6. Kaufman OS. Kong CSt Shizuru JA. et al: Transplantation 46:210. 1988 

FK 506: An effective immunosuppressant for islet xenotransplantation

http://d-scholarship.pitt.edu/4838/1/31735062112432.pdf

FK 506: An effective immunosuppressant for islet xenotransplantation

Abstract

Similar works

Full text

Available Versions

Name not available

Name not available

University of Miami: Scholarship@Miami

D-Scholarship@Pitt