Isotretinoin ameliorates renal damage in experimental acute renal allograft rejection.
BACKGROUND
Retinoic acids, derivatives of vitamin A, act through retinoid receptors that are expressed in renal and immunocompetent cells (B and T cells; monocytes and macrophages). In experimental models of glomerulonephritis and renal interstitial disease, retinoids were shown to reduce both glomerular and tubular damage and inflammation. We therefore examined whether retinoids reduce cellular rejection and renal damage in a model of acute renal allograft rejection.


METHODS
Kidneys of Fisher rats (F344, RT11v1) were orthotopically grafted to Lewis rats (RT11). Animals were killed 7 or 14 days after transplantation. Rats undergoing transplantation were treated with isotretinoin (13 cis-retinoic acid) at a low dose of 2 mg/kg body weight per day (LD isotretinoin) or at a high dose of 20 mg/kg body weight per day (HD isotretinoin) or with vehicle.


RESULTS
At day 14, albuminuria was reduced by approximately 70% (vehicle: 1.1+/-0.2 mg/24 hr vs. LD isotretinoin: 0.32+/-0.1 mg/24 hr; P<0.001). At days 7 and 14 serum creatinine levels were significantly higher in the vehicle-treated group than in the LD and HD isotretinoin-treated rats (P<0.05). Both LD and HD isotretinoin significantly reduced acute vascular injury compared with vehicle-treated rats (score at day 14: LD isotretinoin 20.1+/-5.1 vs. vehicle 57.8+/-9.9, P<0.01), acute glomerular injury (score: LD isotretinoin 6.8+/-1.0 vs. vehicle 10.6+/-0.9 P<0.05), and the number of glomerular monocytes and macrophages and cytotoxic T cells. Isotretinoin also significantly lessened tubulointerstitial damage, tubulointerstitial cell proliferation, and the number of cells infiltrating the tubulointerstitium.


CONCLUSIONS
Isotretinoin significantly ameliorated functional, vascular, glomerular, and tubulointerstitial lesions in acute graft rejection. Although the current study did not definitely eliminate the possibility that isotretinoin only delayed the rejection process, retinoic acid derivatives may provide a new approach in the treatment of acute rejection injury.
Kiss
Eva
E
Department of Cellular and Molecular Pathology, German Cancer Research Center, Heidelberg, Germany.
Adams
Judith
J
Gröne
Hermann-Josef
HJ
Wagner
Jürgen
J
D000419:Albuminuria / Q000209:etiology; D000818:Animals; D003401:Creatine / Q000097:blood; D006084:Graft Rejection / Q000517:prevention & control*; D007150:Immunohistochemistry; D015474:Isotretinoin / Q000008:administration & dosage / Q000494:pharmacology*; D007668:Kidney / Q000187:drug effects* / Q000473:pathology; D007678:Kidney Glomerulus / Q000187:drug effects / Q000473:pathology; D016030:Kidney Transplantation / Q000276:immunology*; D008297:Male; D051381:Rats; D011916:Rats, Inbred F344; D011917:Rats, Inbred Lew
D015474:Isotretinoin; D003401:Creatine