Reconstruction of the intestinal lymphatic drainage after small bowel transplantation

The surgical procedure of small bowel transplantation normally results in complete disruption of the graft's lymphatic drainage. The present study was undertaken to determine the impact of lymphatic reconstruction (LR) on the outcome of intestinal grafting, using a microsurgical model that immediately restores lymphatic drainage.

Brown Norway (RT1n) intestinal grafts were orthotopically transplanted into Lewis (RT1(1)) rats either with LR (+LR) or without LR (-LR). Recipients were randomly allocated into the following groups: no treatment or cyclosporine (CsA) at a dose of 2, 5, or 10 mg/kg/day subcutaneously from postoperative day (POD) 0 to 6.

There was morphological regeneration of lymphatics in the -LR group between 1-3 weeks as previously reported, whereas normal lymph flow was immediately restored in the +LR group. All untreated and CsA(2 mg)-treated allografts were rapidly rejected in both the +LR and -LR groups. In the groups treated with approximately 5 mg of CsA, five of six -LR animals died of chronic rejection between 38 and 86 days (mean survival time +/- SD: 76.7+/-21 days), while all +LR animals survived until death on POD 100 (P < 0.05). Histological features of mucosal damage found in -LR grafts were absent in the +LR grafts. All of the animals treated with 10 mg of CsA survived indefinitely. Sequential histology revealed mild rejection in -LR and +LR grafts on POD 45, but +LR animals had significantly higher body weight gains (POD 50: -LR: 117+/-12% vs. +LR: 136+/-4%, P < 0.01). LR did not affect donor cell migration and nutritional parameters.

LR improves the long-term results of small bowel transplantation resulting in better survival rates, less mucosal damage due to chronic graft rejection, and greater weight gain. We conclude that impairment of lymph flow may contribute to poor outcomes when standard surgical techniques are used for small bowel transplantation.