Azza S. Awad

Curcumin immune-mediated and anti-apoptotic mechanisms protect against renal ischemia/reperfusion and distant organ induced injuries.

Renal ischemia followed by reperfusion results in kidney injury which in turn produces and releases destructive inflammatory cytokines into the circulation causing subsequent distant organ injury. Little data suggest the immune mechanism of curcumin on protection against ischemia/reperfusion induced injury. We investigated the immunomodulatory and anti-apoptotic effects of curcumin on ischemia/reperfusion (I/R) injury in rats. Thirty-six rats were randomly divided into three experimental groups (sham, I/R and curcumin pretreated I/R, n=12 each). Curcumin was administered orally to curcumin pretreated I/R group. Curcumin can significantly decrease both systemic as well as blood levels of cytokines (p<0.05). Treatment with curcumin also resulted in significant reduction in serum and tissue level of TNF-α, IL-1β, IL-12, IL-18 and INF-γ that were increased by renal I/R injury (p<0.05). Curcumin pretreatment reduce pulmonary apoptotic pathway via significant inhibition of TGF-β and caspase-3 in kidney and lung tissues. Given that pulmonary apoptosis is an important complication of acute renal injury, we identified curcumin protective effect against distant organ I/R induced injury. Based on our results, we concluded that curcumin protects the kidneys and other vital organs against I/R injury via immune-mediated and the new identified anti-apoptotic mechanisms.

Effect of thymoquinone on hepatorenal dysfunction and alteration of CYP3A1 and spermidine/spermine N‐1‐acetyl‐transferase gene expression induced by renal ischaemia–reperfusion in rats

Objectives  Renal ischaemia–reperfusion (I/R) is a well‐characterised model of acute renal failure that causes both local and remote organ injury. The aim of this work was to investigate the effect of thymoquinone, the main constituent of the volatile oil extracted from Nigella sativa seeds, on renal and hepatic changes after renal ischaemia–reperfusion.

Thymoquinone blocks lung injury and fibrosis by attenuating bleomycin-induced oxidative stress and activation of nuclear factor Kappa-B in rats

Pulmonary fibrosis is one of the most common chronic interstitial lung diseases with high mortality rate after diagnosis and limited successful treatment. The present study was designed to assess the potential antifibrotic effect of thymoquinone (TQ) and whether TQ can attenuate the severity of oxidative stress and inflammatory response during bleomycin-induced pulmonary fibrosis. Male Wister rats were treated intraperitoneally with either bleomycin (15 mg/kg, 3 times a week for 4 weeks) and/or thymoquinone (5mg/kg/day, 1 week before and until the end of the experiment). Bleomycin significantly increased lung weight and the levels of Lactate dehydrogenase, total leucocytic count, total protein and mucin in bronchoalveolar lavage and these effects were significantly ameliorated by TQ treatment. As markers of oxidative stress, bleomycin caused a significant increase in the levels of lipid peroxides and nitric oxide accompanied with a significant decrease in the antioxidant enzyme activity of superoxide dismutase and glutathione transferase. TQ treatment restored these markers toward normal values. TQ also counteracted emphysema in air alveoli, inflammatory cell infiltration, lymphoid hyperplastic cells activation surrounding the bronchioles and the over expression of activated form of nuclear factor kappa-B (NF-B) in lung tissue that was induced by bleomycin. Fibrosis was assessed by measuring hydroxyproline content, which increased markedly in the bleomycin group and significantly reduced by concurrent treatment with TQ. Furthermore, histopathological examination confirmed the antifibrotic effect of TQ. Collectively these findings indicate that TQ has potential antifibrotic effect beside its antioxidant activity that could be through NF-κB inhibition.

Insights antifibrotic mechanism of methyl palmitate: Impact on nuclear factor kappa B and proinflammatory cytokines

Fibrosis accompanies most chronic liver disorders and is a major factor contributing to hepatic failure. Therefore, the need for an effective treatment is evident. The present study was designed to assess the potential antifibrotic effect of MP and whether MP can attenuate the severity of oxidative stress and inflammatory response in chronic liver injury. Male albino rats were treated with either CCl(4) (1 ml/kg, twice a week) and/or MP (300 mg/kg, three times a week) for six weeks. CCl(4)-intoxication significantly increased liver weight, serum aminotransferases, total cholesterol and triglycerides while decreased albumin level and these effects were prevented by co-treatment with MP. As indicators of oxidative stress, CCl(4)-intoxication caused significant glutathione depletion and lipid peroxidation while MP co-treatment preserved them within normal values. As markers of fibrosis, hydroxyproline content and α-SMA expression increased markedly in the CCl(4) group and MP prevented these alterations. Histopathological examination by both light and electron microscope further confirmed the protective efficacy of MP. To elucidate the antifibrotic mechanisms of MP, the expression of NF-κB, iNOS and COX-2 and the tissue levels of TNF-α and nitric oxide were assessed; CCl(4) increased the expression of NF-κB and all downstream inflammatory cascade while MP co-treatment inhibited them. Collectively these findings indicate that MP possesses a potent antifibrotic effect which may be partly a consequence of its antioxidant and anti-inflammatory properties.

Effect of Combined Treatment With Curcumin and Candesartan on Ischemic Brain Damage in Mice

The combined effects of curcumin and candesartan were investigated in brain ischemia induced by middle cerebral artery (MCA) occlusion (MCAO). Male mice were classified into 5 groups. The mice were killed 24 hours after MCAO, and each group was divided into 2 halves. In one half, brain homogenate was collected for antioxidant enzyme activity determination, and in the other half, samples were obtained for red color intensity determination in brain slices. The untreated group exhibited significantly reduced cerebral blood flow, increased lipid peroxide levels and heart rate, decreased superoxide dismutase (SOD) and glutathione-S-transferase (GST) activity, and reduced red color intensity compared with the sham group. Combination treatment with curcumin and candesartan significantly restored SOD and GST activity, thiobarbituric acid reactive substances, heart rate, blood flow, and red color intensity compared with the untreated group. The use of each drug alone significantly restored SOD and blood flow compared with the sham and untreated groups, heart rate decreased with curcumin alone, and red color intensity and nitric oxide level increased with candesartan alone. These results indicate that curcumin synergistically enhances the inhibitory action of candesartan on brain ischemia through suppression of blood flow changes and oxidative stress via antioxidant properties, suggesting beneficial combined effects of curcumin and candesartan on ischemic brain damage.

Immunomodulatory effects of rosuvastatin on hepatic ischemia/reperfusion induced injury

Liver ischemia followed by reperfusion results in liver injury which in turn produces and releases destructive proinflammatory cytokines into the circulation causing subsequent damage to other organs. This remains a significant problem for surgical procedures and liver transplantation. Objective: In this study, we show the effect of rosuvastatin on multiple organ dysfunction induced by hepatic/ischemia reperfusion. Materials and methods: Hepatic ischemia and reperfusion (I/R) injury was induced in rats, and groups of rats were pretreated with oral rosuvastatin. Results: Our study detected the levels of tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), IL-10, and monocyte chemotactic protein 1 (MCP-1) not only in serum but also in liver, lung, kidney intestine, and heart tissues. Rosuvastatin pretreatment appears to protect these organs after hepatic I/R injury through the reduction of proinflammatory cytokines (TNF-α, IL-6, and MCP-1) and stimulation of anti-inflammatory cytokines (IL-10) production. Discussion and conclusion: This is the first report of rosuvastatin immunomodulatory effects on multiorgan dysfunction after hepatic I/R. Our data suggest a therapeutic potential for rosuvastatin in attenuating inflammation and modulating immune response independent of lipid lowering effect.

Effect of rosuvastatin on cholestasis‐induced hepatic injury in rat livers

Recent studies reported that 3‐hydroxy‐3‐methyl‐glutaryl coenzyme A (HMG‐CoA) reductase inhibitors have pleotropic effects independent of their lipid‐lowering properties. The present study was undertaken to determine whether treatment with rosuvastatin (RO) would be beneficial in a rat model of bile duct ligation (BDL). Animals were divided into three groups: a sham group (group I), a BDL group treated with vehicle (group II), and a BDL group treated with RO (10 mg/kg) (group III). Serum levels of total bilirubin, γ‐glutamyl transpeptidase, alanine aminotransferase, and aspartate aminotransferase decreased significantly in group III when compared to group II. Lipid peroxides and NO levels of group III were found to be significantly lower than those of group II. Antioxidant enzymes (superoxide dismutase, glutathione‐S‐transferase, and catalase) activity in liver tissues markedly decreased in group II, whereas treatment with RO preserved antioxidant enzyme activity. DT‐diaphorase activity in group II was significantly higher than that in group III. The histopathological results showed multiple numbers of newly formed bile ductules with inflammatory cells infiltration in group II. These pathological changes were improved in group III. Our data indicate that RO ameliorates hepatic injury, inflammation, lipid peroxidation and increases antioxidant enzymes activity in rats subjected to BDL. RO may have a beneficial effect on treatment of cholestatic liver diseases.

Antifibrotic mechanism of deferoxamine in concanavalin A induced-liver fibrosis: Impact on interferon therapy.

Iron-overload is a well-known factor of hepatotoxicity and liver fibrosis, which found to be a common finding among hepatitis C virus patients and related to interferon resistance. We aimed to elucidate the potential antifibrotic effect of deferoxamine; the main iron chelator, and its additional usefulness to interferon-based therapy in concanavalin A-induced immunological model of liver fibrosis. Rats were treated with deferoxamine and/or pegylated interferon-α for 6 weeks. Hepatotoxicity indices, oxidative stress, inflammatory and liver fibrosis markers were assessed. Concanavalin A induced a significant increase in hepatotoxicity indices and lipid peroxidation accompanied with a significant depletion of total antioxidant capacity, glutathione level and superoxide dismutase activity. Besides, it increased CD4(+) T-cells content and the downstream inflammatory cascades, including NF-κB, TNF-α, iNOS, COX-2, IL-6 and IFN-γ. Furthermore, α-SMA, TGF-β1 and hydroxyproline were increased markedly, which confirmed by histopathology. Treatment with either deferoxamine or pegylated interferon-α alone reduced liver fibrosis markers significantly and improved liver histology. However, some of the hepatotoxicity indices and oxidative stress markers did not improve upon pegylated interferon-α treatment alone, besides the remarkable increase in IL-6. Combination therapy of deferoxamine with pegylated interferon-α further improved all previous markers, ameliorated IL-6 elevation, as well as increased hepcidin expression. In conclusion, our study provides evidences for the potent antifibrotic effects of deferoxamine and the underlying mechanisms that involved attenuating oxidative stress and subsequent inflammatory cascade, as well as the production of profibrogenic factors. Addition of deferoxamine to interferon regimen for HCV patients may offer a promising adjuvant modality to enhance therapeutic response.

Cardiac dt-diaphorase contributes to the detoxification system against doxorubicin-induced positive inotropic effects in Guinea-pig isolated atria

1. Doxorubicin (DOX), a standard chemotherapeutic anthracycline agent, causes a positive inotropic effect in guinea‐pig isolated atria in a concentration‐dependent manner with an ED50 of 3.6 µmol/L. This increase in contractility is strictly related to the generation of reactive oxygen species (ROS) as a consequence of quinone metabolism. The ED50 of DOX is significantly increased (P < 0.05) in the presence of 150 U superoxide dismutase (SOD). In the heart, DOX may be subjected to one‐ or two‐electron reductions catalysed by flavoenzymes in the presence of suitable electron donors. Two‐electron reduction is catalysed by NAD(P)H quinone acceptor oxidoreductase (DT‐diaphorase; DTD). Whether DOX will be activated or detoxified by two‐electron reduction is important for the understanding of the mechanism of both the toxic and antitumour actions of DOX.

Immunomodulatory effect of candesartan on indomethacin-induced gastric ulcer in rats

Non steroidal anti-inflammatory drugs (NSAIDs) induce gastric mucosal lesions in part by induction of oxidative stress as well as the activation of inflammatory cells and the production of proinflammatory cytokines. In this study, we examined the protective effect of candesartan (2 and 5 mg/kg) on indomethacin-induced gastric mucosa damage. Pretreatment with candesartan for 10 days reduced significantly the ulcer index induced by indomethacin injection. The preventive index of 2 mg/kg (76.74%) was higher than that of 5 mg/kg (65.11%). Both doses of candesartan were able to reduce significantly the stomach malondialdehyde content compared to indomethacin-treated group. Myeloperoxidase, tumor necrosis factor-α, cytokine-induced neutrophil chemoattractant gastric levels were significantly reduced by 2 mg/kg of candesartan more than 5 mg/kg. The Th1 cytokine interferon γ was also significantly reduced by both doses of candesartan compared to indomethacin injected group. On the other hand, indomethacin significant decreased the anti-inflammatory cytokine IL-10 gastric level. Pretreatment with candesartan (2 and 5 mg/kg) reversed this effect. In conclusion, the present study indicates that pretreatment with candesartan, can protect against the stomach injury induced by indomethacin through its antioxidant and immunomodulatory effects.