Oxidative Stress in Cyclosporine-Induced Hypertension: Evidence of Beneficial Effects or Tolerance Development With Nitrate Therapy

Abstract

The aim of this study was to evaluate the effect of cyclosporine (CsA) on oxidative stress as well as the use of a nitric oxide (NO) donor, the organic nitrate isosorbide-5-mononitrate (Is-5-Mn), to prevent or reverse CsA-induced toxicity, namely on the vascular NO-cGMP pathway or on oxidative equilibrium. The following rat groups (n ϭ 8) were tested: (1) a control group; (2) the CsA group (5 mg/kg/d for 7 weeks); (3) the Is-5-Mn group (150 mg/kg/d, twice a day for 7 weeks); (4) the preventive group (Is-5-Mn ϩ CsA) treated for 2 weeks with Is-5-Mn only, and thereafter with both drugs for 7 weeks; (5) the curative group (CsA ϩ Is-5-Mn) beginning 7 weeks after CsA, and following thereafter with both drugs for 5 weeks. The following parameters were evaluated: aortic cNOS activity and cGMP content; plasma levels of lipid peroxidation (malondialdehyde [MDA] levels); antioxidant capacity (glutathione peroxidase [GPx] and superoxide dismutase [SOD] activities, total antioxidant status, and vitamins A, C, and E); and peroxynitrite formation (3-nitrotyrosine [3-NT] content). Is-5-Mn ϩ CsA therapy showed, when compared with the CsA group, total prevention of CsAinduced NO and cGMP attenuation, and no relevant influence on antioxidant indices, as well as on MDA and 3-NT levels. However, when compared with this CsA group, the curative group (CsA ϩ Is-5-Mn) showed NO-cGMP values only partially reversed, and an enhancement in lipid peroxidation (5.6 Ϯ 1.4 vs 12.78 Ϯ 3.63 mol/L; P Ͻ .05) and in peroxynitrite formation (16.7% incidence of positives vs 83.3% incidence of positives). Our data suggested that nitrate therapy may provide a valid choice to prevent CsA-induced NO-cGMP decrease, without a negative influence on the oxidative equilibrium. However, when the local environment is adverse, as occurs after CsA therapy, Is-5-Mn seemed to enhance the CsA-induced oxidative stress, promoting even worse deleterious effects, probably through the generation of the cytotoxic ROS peroxynitrite.

Cyclosporin-A Induced Toxicity in Rat Renal Collecting Duct Cells: Interference with Enhanced Hypertonicity Induced Apoptosis

“…The influence of CsA on ROS appears just as heterogeneous as the effect of ROS on cell viability. Some authors describe increase of ROS and lipid peroxidation in a rat model after 7 days of CsA treatment and observe beneficial effects of parallel administration of antioxidants [35], but in other animal models serum parameters of antioxidant status were not changed after 7 weeks of CsA treatment [36]. In our study we provide evidence that during elevation of extracellular osmolality ROS are not altered by additional treatment with CsA (Fig.…”

Renal effects of soluble guanylate cyclase stimulators and activators: A review of the preclinical evidence

“…NO deficiency has been documented in numerous experimental and human renal diseases, including hypertension and diabetic nephropathy, glomerulosclerosis, obstructive nephropathy, and chronic interstitial nephritis, as well as renal diseases due to cyclosporine A and radiocontrast media [13][14][15][16][17][18][19][20][21].…”

Renoprotective Effects of Naringenin and Olive Oil against Cyclosporine- Induced Nephrotoxicity in Rats

“…Although acute and chronic CsA-induced nephrotoxicity are well established, the underlying mechanism remains debatable [3], with several distinct possibilities, including a direct effect due to calcineurin inhibition, overexpression of fibrotic mediators, such as the transforming growth factor-ß1 (TGF-ß1), the impairment of vasoactive substances, including angiotensin II, nitric oxide (NO), thromboxane A (TXA), serotonin, catecholamine and leukotriene, as well as, increased generation of reactive oxygen species "ROS" and consequent oxidative stress [4,5].…”