ELSEVIER Small Bowel Myoelectrical Activity After Transplantation in Pigs: Motility Versus ACR Score A. Costa, F. De Ponti, M. Spada, E. Arbustini, P. Morbini, S. Vaccarisi, F. Fayer, M. Dermitzakis, M. Douvli, F. Crema, M. Alessiani, and A. Crema R ELIABLE TESTS to assess graft viability are needed to monitor the postoperative period following organ transplantation. In particular, with a regard to small bowel transplantation, unlike other solid organ transplantations (eg, kidney, liver, or pancreas), no biochemical markers are presently available to assess the functional recovery of small bowel grafts routinely. Therefore, functional tests such as absorption tests are used. Since only a few data are avail- able on intestinal graft motility, we performed this study to monitor the recovery of small bowel grafts as well as the onset and the severity of rejection in pigs under FK 506 immunosuppressive therapy by simultaneously monitoring both myoelectrical activity and acute rejection (ACR) score as determined by mucosal biopsies. MATERIALS AND METHODS Total orthotopic small bowel transplantation was performed in 16 outbred piglets (26 i- 6 kg body weight) from equivalent donors perfused through the aorta with the UW solution at 4°C. Intestinal continuity was obtained performing a side-to-side and end-to-end anastomosis with the recipient’s jejunum and terminal ileum, respectively.’ Animals were divided into four groups according to the different immunosuppressive therapy: group 1 and group 2 animals were treated with FK 506, 0.15 and 0.3 mg/kg/d, respec- tively: group 3 animals were treated with FK 506 0.3 mg/kgid, only up to postoperative day 7. Four nontransplanted pigs served as normal controls (group 4). All animals (each group n = 4) were chronically fitted with eight bipolar electrodes implanted on the antimesenteric border along the small bowel at the following levels: descending duodenum (E,) and first loop of the jejunum (EJ in the residual recipient’s small bowel; the others (E, to E8) were placed every 50 cm in an abroad direction along the graft. In all animals, antibiotic prophylaxis consisted of gentamycin 160 mg daily and cefotaxime 3 g daily for 7 days. Myoelectrical activity was recorded in conscious fasting animals for at least 4 hours on postoperative days 1, 3, 7, 11, and 14 by a multichannel recorder (Neuro 20, Battaglia Rangoni, Casalecchio di Reno, Italy) with a time constant of 0.03 seconds and simultaneously stored by a computerized system that automatically calculates the mean num- ber of spikes per unit of time (1 hour in this study) by means of original software.’ The severity of acute rejection was monitored by mucosal biopsies obtained from the graft jejunal stoma on the same days of motility recording and was assessed according to a previ- ously described histological grading (ACR score ranging from 0 to 3).’ RESULTS Up until day 7, the mean number of spikes per hour was similar to the control values only in group 2 and group 3 animals (Table l), in which the ACR score showed absence of rejection. On the contrary, in group 1 the number of spikes per hour was consistently lower, and the ACR score showed the presence of moderate rejection (Table 1). In group 3 animals, on day 14 (ie, one week after FK 506 withdrawal), the number of spikes per hour was significantly reduced and the severity of acute rejection markedly in- creased (Table 1). When considering all animals, the mean From the Department of Internal Medicine and Therapeutics (A.C., F.D.P., F.C., A.C.), Surgery, (M.S., S.V., F.F., M.D., M.D., M.A.) and Pathology (E.A., P.M.), University of Pavia, I.R.C.C.S. Policlinico S. Matteo, Pavia, Italy. Address reprint requests to M. Alessiani, Patol6gia Chirurgica I, Policlinico S. Matteo, P. le Golgi 2, 27100 Pavia, Italy. Table 1. Myoelectrical Parameters Recorded in the Transplanted Small Bowel in the Pig Group n Dose (mg/kg/d) Spikes Per Hour ACR Score Day 7 Day 14 Day 7 Day 14 1 4 0.15 IM 4440 k 323’ 4273 IT 88l* 1.25 + 0.25’ 1.63 -t 0.24 2 4 0.30 IM 7577 k 1138 5943 k 974 0.50 + 0.18 0.94 2 0.12 3 4 0.30 IM withdrawn 7384 k 848 4294 k 643’ 0.25 -c 0.24 1.63 2 0.24+ on day 7 4 (Control) 4 - 6109 t 581 6791 2 1275 - - ACR scores indicate the following degreesof acute rejection: 0 to 1 = none to mild; 1 to 2 = mild to moderate; and 2 to 3 = moderate to severe. Values are means * SE; ‘P < .05 “s control, +P < .05 “s day 7, and *P < .05 “s group 2 and group 3 on the same day. 0 1997 by Elsevier Science Inc. 0041-l 345/97/$17.00 655 Avenue of the Americas, New York, NY 10010 PII so041 -1345(97)00077-8 Transplantation Proceedings, 29, 1809-l 810 (1997) 1809