tretinoin and Nephritis

Mercuric chloride (HgCl2) induces an autoimmune nephritis in the Brown Norway (BN) rats characterized by anti-glomerular basement membrane antibodies (anti-GBM Ab) deposition, proteinuria and a severe interstitial nephritis, all evident at day 13 of the disease. We assessed the effects of all-trans retinoic acid (at-RA) in this experimental model. At-RA is a vitamin A metabolite which has shown beneficial effects on several nephropathies, even though no clear targets for at-RA were provided.. We separated animals in four different experimental groups (HgCl2, HgCl2+at-RA, at-RA and vehicle). From each animal we collected, at days 0 and 13, numerous biological samples: urine, to measure proteinuria by colorimetry; blood to determine VLA-4 expression by flow citometry; renal tissue to study the expression of VCAM-1 by Western blot, the presence of cellular infiltrates by immunohistochemistry, the IgG deposition by immunofluorescence, and the cytokines expression by RT-PCR. Additionally, adhesion assays to VCAM-1 were performed using K562 alpha4 transfectant cells. ANOVA tests were used for statistical significance estimation.. We found that at-RA significantly decreased the serum levels of anti-GBM and consequently its deposition along the glomerular membrane. At-RA markedly reduced proteinuria as well as the number of cellular infiltrates in the renal interstitium, the levels of TNF-alpha and IL-1beta cytokines and VCAM-1 expression in renal tissue. Moreover, we reported here for the first time in an in vivo model that at-RA reduced, to basal levels, the expression of VLA-4 (alpha4beta1) integrin induced by mercury on peripheral blood leukocytes (PBLs). In addition, using K562 alpha4 stable transfectant cells, we found that at-RA inhibited VLA-4 dependent cell adhesion to VCAM-1.. Here we demonstrate a therapeutic effect of at-RA on an autoimmune experimental nephritis model in rats. We report a significant reduction of the VLA-4 integrin expression on PBLs as well as the inhibition of the VLA4/VCAM1-dependent leukocyte adhesion by at-RA treatment. Thereby we point out the VLA-4 integrin as a target for at-RA in vivo.

Topics: Animals; Autoimmune Diseases; Disease Models, Animal; Dose-Response Relationship, Drug; Immunity, Innate; Immunosuppressive Agents; Integrin alpha4beta1; Male; Mercuric Chloride; Nephritis; Rats; Treatment Outcome; Tretinoin

We previously demonstrated that all-trans retinoic acid (RA) preserves glomerular structure and function in anti-Thy1.1 nephritis (Wagner J, Dechow C, Morath C, Lehrke I, Amann K, Floege J, and Ritz E. J Am Soc Nephrol 11: 1479-1489, 2000). Because the renin-angiotensin system (RAS) contributes to renal damage, we 1) studied retinoid-specific effects on its components and 2) compared the effects of all-trans-RA with those of the AT(1)-receptor blocker candesartan. Rats were pretreated for 3 days before injection of the OX-7 antibody and continued with treatment with either vehicle or daily injections of 10 mg/kg all-trans-RA only (study 1) or 10 mg/kg body wt all-trans-RA, 1 mg/kg candesartan, or both (study 2) for an additional 7 days. The blood pressure increase observed in anti-Thy1.1 nephritic rats was equally normalized by all-trans-RA and candesartan (P < 0.05). In nephritic rats, mRNAs of angiotensinogen and angiotensin-converting enzyme (ACE) in the kidney were unchanged, but renin mRNA was lower (P < 0.01). Renal and glomerular AT(1)-receptor gene and protein expression levels were higher in anti-Thy1.1 nephritic rats (P < 0.05). In the renal cortex of nephritic rats, pretreatment with all-trans-RA significantly reduced mRNAs of all the examined RAS components, but in the glomeruli it increased ACE gene and protein expression (P < 0.01). In nephritic rats, candesartan reduced the number of glomerular cells and mitoses (P < 0.05) less efficiently than all-trans-RA (P < 0.01). Both substances reduced cellular proliferation (proliferating cell nuclear antigen) significantly (P < 0.05). No additive effects were noted when both compounds were combined. In conclusion, all-trans-RA influences the renal RAS in anti-Thy1.1 nephritis by decreasing ANG II synthesis and receptor expression. The beneficial effect of retinoids may be explained, at least in part, by reduction of RAS activity.

Topics: Angiotensin II; Angiotensin Receptor Antagonists; Angiotensinogen; Animals; Antibodies; Benzimidazoles; Biphenyl Compounds; Blood Pressure; Kidney; Kidney Glomerulus; Male; Nephritis; Peptidyl-Dipeptidase A; Proto-Oncogene Proteins c-fos; Rats; Rats, Wistar; Receptor, Angiotensin, Type 1; Receptors, Mineralocorticoid; Renin; Renin-Angiotensin System; RNA, Messenger; Tetrazoles; Thy-1 Antigens; Tretinoin

Bone marrow transplant (BMT) nephropathy is characterized by the acute onset of nephritis more than 100 days after BMT. The renal lesion in BMT nephropathy is similar to radiation nephritis, but BMT nephropathy occurs earlier and with lower radiation doses than radiation nephritis. The combined effects of chemotherapeutic agents and nephrotoxic drugs given before and after BMT appear to sensitize or unmask radiation nephritis. Reporting of drugs that may contribute to BMT nephropathy is critical for the development of optimal treatment regimens. Herein, we report two cases of BMT nephropathy that developed coincident with retinoic acid therapy. Both patients received autologous BMT for neuroblastoma after preparative therapy with total body irradiation/melphalan/carboplatin/etoposide. They were randomized to receive cis-retinoic acid as part of a clinical trial. Both patients developed acute nephritis during their second 2-week course of retinoic acid on post-BMT days 105 and day 139. The nephritis was associated with hypertension, anemia, thrombocytopenia, azotemia, hematuria, and proteinuria. Clinical features, laboratory evaluation, and renal biopsy indicated that these two patients developed radiation-induced BMT nephropathy. The fact that both patients developed nephritis concurrent with retinoic acid therapy raises a concern that retinoic acid may have unmasked radiation injury and triggered BMT nephropathy.

Topics: Adrenal Gland Neoplasms; Antineoplastic Agents; Bone Marrow Transplantation; Child, Preschool; Glomerular Mesangium; Humans; Kidney; Male; Nephritis; Time Factors; Tretinoin