isotretinoin and Glomerulonephritis

Retinoids reduce renal damage in rat experimental glomerulonephritis. It is unknown, however, how local and systemic retinoid pathways respond to renal injury. We used a rat model of artificially induced acute anti-Thy1.1-nephritis (THY-GN). We examined the extrarenal and glomerular expression of the retinol (RoDH) and retinal (RalDH) dehydrogenases 1 and 2 as well as the expression of the retinoic acid (RAR) and retinoid X (RXR) receptor subtypes alpha, beta, and gamma. Furthermore, we investigated serum and glomerular retinoid concentration patterns. On days 3, 7, and 14, we compared nonnephritic rats (control group; CON) to THY-GN rats with respect to systolic blood pressure and glomerular cell count per cross section. Systolic blood pressure and glomerular cell count were significantly higher in THY-GN rats on days 7 and 14 (P < 0.001). We found a 60% reduction in expression levels for retinoid receptors and dehydrogenases in nephritic glomeruli on day 3, but a threefold increase on day 7 (P < 0.001 vs. CON). The same applies to RAR alpha protein. Hepatic expression of retinoid receptors was not influenced. On day 14, glomerular expression levels for retinoid receptors and retinoid-metabolizing enzymes had returned to a normal level, glomerular cell count being still increased. Administering 13-cis retinoic acid (isotretinoin) lowered blood pressure and glomerular cell count in nephritic rats but failed to influence the glomerular expression of retinoid receptors or retinoid-metabolizing enzymes. Our data document a stimulation of glomerular retinoid-synthesizing enzymes and expression of retinoid receptors in the early repair phase of THY-GN, suggesting activation of this system in acute renal disease.

Topics: Alcohol Oxidoreductases; Aldehyde Oxidoreductases; Animals; Blood Pressure; Cell Count; Cytochrome P450 Family 2; Glomerulonephritis; Isotretinoin; Kidney Glomerulus; Kinetics; Liver; Male; Rats; Rats, Wistar; Receptors, Retinoic Acid; Retinal Dehydrogenase; Retinoid X Receptors; Retinoids; RNA, Messenger; Transcription Factors

Transforming growth factor-beta1 (TGF-beta 1) overexpression plays a key role in the glomerular accumulation of extracellular matrix proteins in renal disease. Retinoids have previously been shown to significantly limit glomerular damage in rat experimental glomerulonephritis. Therefore, the effects of all-trans retinoic acid and isotretinoin on the components of the TGF-beta system and extracellular matrix proteins in anti-Thy1.1-nephritis (Thy-GN) were investigated. Vehicle-injected control rats were compared with rats treated with daily subcutaneous injections of 10 mg/kg body wt all-trans retinoic acid or 40 mg/kg body wt isotretinoin (n = 9 per group) either with a pretreatment (day -2 through 8) or posttreatment protocol (day +3 through 8), i.e., starting before or after induction of Thy-GN, respectively. Urinary TGF-beta 1 excretion was 60% lower in all-trans retinoic acid-treated animals with Thy-GN (P < 0.025). The increase of cortical TGF-beta 1 gene expression in Thy-GN rats was significantly attenuated with all-trans retinoic acid and even more with isotretinoin treatment as compared with untreated animals (P < 0.025). Cortical expression of TGF receptor II, but not receptor I gene expression, was significantly lower in animals treated with all-trans retinoic acid or isotretinoin (P < 0.05). In all-trans retinoic acid-treated animals with Thy-GN, the increase of glomerular TGF-beta 1 protein (P < 0.008) and TGF-beta 1 (P < 0.025) and TGF receptor II mRNA (P < 0.015) was significantly less. Immunohistochemistry revealed less glomerular staining for TGF-beta 1 and TGF receptor II in the presence of all-trans retinoic acid. TGF-beta 1 immunostaining was not restricted to monocytes and macrophages, as indicated by double-staining. Glomerular staining for collagen IV and collagen III was less in animals treated with isotretinoin (P < 0.02 for both) in contrast to all-trans retinoic acid, whereas fibronectin remained unchanged. It was concluded that the beneficial effects of retinoids on glomerular damage are presumably due to a marked reduction in renal TGF-beta 1 and TGF receptor II expression.

Topics: Animals; Antibodies, Monoclonal; Blood Pressure; Extracellular Matrix; Gene Expression; Glomerulonephritis; Isotretinoin; Kidney Cortex; Kidney Glomerulus; Male; Protein Serine-Threonine Kinases; Rats; Rats, Wistar; Receptor, Transforming Growth Factor-beta Type II; Receptors, Transforming Growth Factor beta; Retinoids; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Systole; Thy-1 Antigens; Transforming Growth Factor beta; Transforming Growth Factor beta1; Tretinoin

Retinoids, derivatives of vitamin A, have strong anti-inflammatory and antiproliferative properties. We previously demonstrated that the pan-agonists all-transretinoic acid (RA) and isotretinoin (13-cis RA) alleviate renal damage in rat acute glomerulonephritis (GN) induced by anti-Thy-1.1 mAb OX-7.. The present study examined the effects of low dose and high dose treatment with isotretinoin in the chronic glomerulonephritis model, Thy-GN. Thy-GN was induced by a single intravenous injection of monoclonal antibody (mAb) 1-22-3 in uninephrectomized Wistar rats (N = 7 to 10 per group). Control and nephritic groups were treated with vehicle (veh), low dose isotretinoin (2 mg/kg body wt), or high dose isotretinoin (10 mg/kg body wt). The experiment was terminated 60 days after induction of Thy-GN.. In animals with Thy-GN, isotretinoin abrogated the increase in blood pressure and significantly reduced albuminuria. Glomerulosclerosis index, glomerular and interstitial cell counts, as well as the area of the interstitial space were significantly lower in nephritic rats treated with low and high dose isotretinoin compared to vehicle-treated nephritic controls. Treatment with isotretinoin also significantly reduced the number of glomerular and interstitial macrophages. The increase of transforming growth factor (TGF)-beta1, TGF receptor II and prepro-endothelin-1 gene expression in vehicle-treated nephritic rats was significantly attenuated by isotretinoin.. Treatment with isotretinoin significantly reduces glomerular and interstitial damage in rats with chronic glomerulonephritis as indicated by different functional and histological markers. Retinoids may provide a novel therapeutic option for the treatment of glomerulonephritis.

Topics: Albuminuria; Animals; Blood Pressure; Body Weight; Chronic Disease; Collagen Type I; Creatinine; Fibronectins; Gene Expression; Glomerulonephritis; Isotretinoin; Kidney; Kidney Glomerulus; Kidney Tubules; Male; Rats; Rats, Wistar

Nitric oxide (NO) release as a result of cytokine-mediated activation of inducible nitric oxide synthase (iNOS) in mesangial cells can be sustained and lead to oxidative injury in various forms of glomerular inflammation. Inhibition of iNOS expression and/or activity could therefore be an effective anti-inflammatory strategy. The present study was undertaken to explore whether retinoids, which are known to have anti-inflammatory and immuno-modulatory actions, can attenuate cytokine-stimulated iNOS expression and enzyme activity in murine mesangial cells.. Expression of iNOS was evaluated by NO production (nitrite analysis), protein (Western blot analysis) and mRNA (RT-PCR analysis) levels in mesangial cells stimulated by a combination of lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma) in the presence and absence of all-trans-retinoic acid (ATRA) or its active metabolite, 13-cis-retinoic acid (13-cis-RA). Changes in iNOS enzyme activity were assessed by calculating conversion of L-[14C]arginine to L-[14C]citrulline. The levels of transcription factors nuclear factor-kappaB (NF-kappaB) and activated protein-1 (AP-1) in nuclear extracts prepared from mesangial cells stimulated by a combination of LPS and IFN-gamma in the presence and absence of ATRA was assessed by immunoblot analysis. The effect of both retinoids on transforming growth factor-beta1 (TGF-beta1) levels was also assessed by a quantitative enzyme immunoassay method.. The combination of LPS/IFN-gamma stimulated NO production, induced iNOS expression (mRNA and protein) and increased iNOS enzyme activity. ATRA and 13-cis-RA dose-dependently attenuated NO production. This effect was most pronounced at ATRA concentration of 10 microM. At this concentration, ATRA attenuated iNOS expression (mRNA and protein levels) and enzyme activity. ATRA also reduced nuclear levels of both subunits (p50 and p65) of NF-kappaB. TGF-beta1 levels in mesangial cells stimulated with LPS/IFN-gamma in presence of ATRA or 13-cis-RA were also reduced indicating that TGF-beta1 did not mediate the suppressive effect of retinoids on iNOS.. Our studies demonstrate that the retinoids ATRA and 13-cis-RA attenuate iNOS expression and activity in cytokine-stimulated murine mesangial cells. These retinoids may emerge as naturally occurring compounds for treatment of inflammatory glomerular diseases.

Topics: Animals; Anti-Inflammatory Agents; Antineoplastic Agents; Cell Line, Transformed; Gene Expression Regulation, Enzymologic; Glomerular Mesangium; Glomerulonephritis; Interferon-gamma; Isotretinoin; Lipopolysaccharides; Mice; NF-kappa B; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Proto-Oncogene Proteins c-fos; RNA, Messenger; Teratogens; Transcription Factor AP-1; Transforming Growth Factor beta; Tretinoin