Objective: We investigated whether degree of immunohistochemically evident endothelin (ET) expression in early post-transplant biopsy specimens could predict long-term allograft function in living-related renal transplantation.
Methods: Allograft biopsy specimens obtained from 40 patients with living-related transplants were studied. Cases with episodes of acute rejection or calcineurin inhibitor toxicity were excluded. We immunostained graft biopsy specimens obtained at pre-transplantation (PRE) and at 3 months (3M) afterward with anti-ET antibody. The number of stained tubular epithelial cells per 1000 tubular cells was defined as the staining index (SI). In the 21 patients whom we could assess at 3 yr (3Y) after transplantation, the correlation between ET expression and long-term graft function was examined.
Results: Anti-ET antibody staining was appreciable in tubular epithelium but not in glomeruli. Tubular SI at PRE and at 3M were 10.6 +/- 15.3 and 32.0 +/- 35.6 (mean +/- SD) respectively (p < 0.01). When patients were classified according to SI (group A, SI < 25; group B, SI > 25), declining ratio in creatinine clearance at 3Y after transplantation for groups A and B with respect was 21.8% +/- 15.4% and 41.9% +/- 21.6% (p < 0.05).
Conclusion: High ET expression in early post-transplantation, biopsy specimens was related to poor long-term allograft function following living-related renal transplantation.