In vitro antioxidant properties of amifostine (WR-2721, Ethyol).

PURPOSE: Amifostine (WR-2721), a phosphorylated aminothiol pro-drug which is an analogue of cysteamine, is a selective cytoprotective agent for normal tissues from the toxicities associated with chemotherapy and irradiation. Despite a growing number of reports strongly supporting amifostine's clinical efficacy, few authors have focused on the biochemical basis of amifostine's antioxidant activity. METHODS: We report on amifostine's free-radical scavenging activity against superoxide (O(2;(-))), hydroxyl (OH(-)) and lipoperoxyl radicals in an in vitro model, using pure chemical systems. Amifostine was dephosphorylated to its active metabolite, WR-1065, by adding 10% non-heat-inactivated serum; different amifostine concentrations (1, 10, 50, 100 microM and 200 microM) and pH conditions (pH 5, 7.4 and 9) were tested. RESULTS: Independent of the concentration, amifostine exhibited no major activity against O(2;(-)) ions, neither did any pH variations in the experimental model provide any scavenger effects of the drug against O(2;(-)) radicals. On the other hand, the protective effect of amifostine against OH(-) radicals was confirmed, yielding an EC(50) of 255 microM at pH 7.4 and 230 microM at pH 5. Finally, amifostine exhibited scavenging activity against spontaneous lipoperoxidation, but no apparent antioxidant effect on iron ascorbate-induced lipoperoxidation. CONCLUSIONS: With this in vitro study, we are able to confirm the scavenging activity of the chemo- and radioprotector amifostine, whose activity seems to be particularly important from a biological point of view, since it is exerted mainly against highly reactive OH(-).

Oxidative stress in the human brain after subarachnoid hemorrhage.

OBJECT: The aim of this study was to verify the patterns of antioxidant enzymatic activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in the human brain after subarachnoid hemorrhage (SAH) to verify whether an "oxidative stress situation" characterizes the brain response to subarachnoid bleeding. METHODS: Forty samples of gyrus rectus or temporal operculum that were obtained during a surgical approach to anterior circulation aneurysms were used for this study. The activity of total SOD, GSH-Px, and the SOD/GSH/Px ratio (which expresses the balance between the production of hydrogen peroxides by dismutation of superoxide radicals and the scavenging potential) were calculated in each case. Twelve samples were obtained from patients who underwent surgery for unruptured aneurysms (control group); 13 samples were obtained during surgical procedures performed within 72 hours of SAH; and 15 samples were obtained during delayed surgical procedures (> 10 days post-SAH). Ten patients presented with clinical deterioration caused by arterial vasospasm. In both SAH groups, the mean total SOD activity was significantly higher than in the control group (p=0.029). The mean activity of GSH-Px did not differ significantly between the SAH and control groups (p=0.731). There was a significant increase in the SOD/GSH-Px ratio in both SAH groups, as compared with controls (p < 0.05). There was a significant correlation between the enzymatic activity and the clinical severity of the hemorrhage, with findings of lower values of SOD and, mainly, of the SOD/GSH-Px ratio in the poor-grade patients. The SOD/GSH-Px ratio was 2.14+/-0.44 in patients who presented with clinical vasospasm and 1.24+/-0.2 in cases without vasospasm. CONCLUSIONS: The results of this study show an imbalance of the antioxidant enzymatic activities in the human brain after SAH. which is linked to the severity of the initial bleeding and possibly modified by the development of arterial vasospasm.

Amifostine (WR-2721, Ethyol(TM)) can protect human endothelial but not tumor cells from cisplatin-induced cytotoxicity.

Amifostine (WR-2721, Ethyol(TM)) is a chemo-and radioprotective agent which is increasingly used in clinical practice to minimize antitumor therapy-induced toxicities. The key of this property of amifostine is certainly its selective action in terms of differential protection of normal tissue and not of tumor cells. Using HUVEC cells and three different cancer cell lines (A549 non-small cell lung cancer, DND-1A melanoma and HeLa cervical carcinoma) we provide evidence that amifostine could protect normal, and not cancer cells, from cisplatin (CDDP)-induced cytotoxicity in vitro. Furthermore, low doses of amifostine, easily attainable in vivo, can protect 50% of normal cells in vitro from CDDP-induced cytotoxicity.

Wheat deficient in gliadins: promising tool for treatment of coeliac disease.

The toxicity of two varieties of bread wheat, one poor in alpha and beta gliadins and the other poor in alpha, beta, gamma, and omega gliadins, has been tested. The peptic-tryptic digest of these wheats was assessed using coeliac mucosa in an in vitro organ culture system. A significantly lower toxicity was found in respect of bread wheat containing all gliadin fractions. These results suggest new opportunities for the treatment of coeliac disease.