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Background Vitamin E δ-tocotrienol (VEDT), a vitamin E compound isolated from sources such as palm fruit and annatto beans, has been reported to have cancer chemopreventive and therapeutic effects. Methods We report a novel function of VEDT in augmenting tumor necrosis factor-related apoptosis-inducing ligand- (TRAIL-) induced apoptosis in pancreatic cancer cells. The effects of VEDT were shown by its ability to trigger caspase-8-dependent apoptosis in pancreatic cancer cells. Results When combined with TRAIL, VEDT significantly augmented TRAIL-induced apoptosis of pancreatic cancer cells. VEDT decreased cellular FLICE inhibitory protein (c-FLIP) levels without consistently modulating the expression of decoy death receptors 1, 2, 3 or death receptors 4 and 5. Enforced expression of c-FLIP substantially attenuated VEDT/TRAIL-induced apoptosis. Thus, c-FLIP reduction plays an important part in mediating VEDT/TRAIL-induced apoptosis. Moreover, VEDT increased c-FLIP ubiquitination and degradation but did not affect its transcription, suggesting that VEDT decreases c-FLIP levels through promoting its degradation. Of note, degradation of c-FLIP and enhanced TRAIL-induced apoptosis in pancreatic cancer cells were observed only with the anticancer bioactive vitamin E compounds δ-, γ-, and β-tocotrienol but not with the anticancer inactive vitamin E compounds α-tocotrienol and α-, β-, γ-, and δ-tocopherol. Conclusions c-FLIP degradation is a key event for death receptor-induced apoptosis by anticancer bioactive vitamin E compounds in pancreatic cancer cells. Moreover, VEDT augmented TRAIL inhibition of pancreatic tumor growth and induction of apoptosis in vivo. Combination therapy with TRAIL agonists and bioactive vitamin E compounds may offer a novel strategy for pancreatic cancer intervention. Electronic supplementary material The online version of this article (10.1186/s12935-019-0876-0) contains supplementary material, which is available to authorized users.

Transport processes are the hallmark of functioning kidney. Various nephrotoxicants disrupt the transport processes to manifest nephrotoxicity. Of several nephrotoxicants, mercuric chloride (HgCl(2)) depletes the reduced glutathione (GSH) in kidney and has been observed to affect the in vitro p-aminohippurate (PAH) transport by basolateral (BL) membrane vesicles. The role of renal nonprotein sulfhydryls such as, reduced GSH has been demonstrated to affect the PAH transport by BL membrane vesicles. The role of protein sulfhydryls in transport process of PAH by BL membrane is not known. Due to mercury mediated effects on sulfhydryls, the effects of protein-sulfhydryls (-SH) modifying reagents in the current study were investigated on PAH transport by BL membrane. It was observed that modification of -SH by p-chloromercuribenzoate sulphate (pCMBS), and mercuric chloride (HgCl(2)) decreased while recovering the protein -SH with dithiothreitol treatment provided protection against the effects of pCMBS, and HgCl(2) on PAH transport by BL membrane vesicles.

A homeostatic balance exists between the cellular generation of oxidant species and endogenous antioxidants under normal physiological conditions. Human Immunodeficiency Virus (HIV) infection is known to affect this balance causing oxidative stress. However, the interaction of HIV infection with a substance abuse on cellular oxidant/antioxidant system is sparse. This study was designed in order to investigate the interactive effect of morphine abuse and Simian Immunodeficiency Virus/ Simian Human Immunodeficiency Virus (SIV/SHIV) infection on plasma oxidant/antioxidant balance in rhesus macaques. Six rhesus macaques adapted to morphine dependence (20 weeks) along with three controls were infected with mixture of SHIV(KU-1B), SHIV(89.6P), and SIV(17E-Fr). Plasma samples from morphine-dependent and control macaques were analyzed for an array of oxidative stress indices after 16 weeks of infection. Morphine-dependence significantly increased plasma malondialdehyde (MDA) and 8-isoprostane levels (8-fold and 2-fold), but these animals showed higher MDA and 8-isoprostane levels after viral infection (18-fold and 4-fold) which was directly correlated with increase in viral load and decline in CD4+ cells. Plasma glutathione (GSH) level depleted (55%) with morphine dependence that was further depleted (25%) by the infection. Activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were increased by 30% and 110%, respectively with morphine dependence, but that was decreased by the infection. Catalase (CAT) activity declined (25%) with morphine dependence that was further declined by infection. Our results clearly suggest that morphine interaction with SIV/SHIV infection causes higher oxidative tissue injury that might have implication in the pathogenesis of AIDS in morphine-dependent macaques.

This study investigated the interactive effects of acute exercise and adenosine receptor agonist and antagonist on antioxidant enzyme activities, glutathione and lipid peroxidation in the heart of the rat. Male Fisher-344 rats were divided into six groups and treated as follows: (1) saline control; (2) acute exercise (100% VO2max); (3) R-Phenyl isopropyl adenosine (R-PIA) (3.46 micromol/kg, i.p.); (4) theophylline (1.70 micromol/kg, i.p.) plus acute exercise; (5) theophylline plus R-PIA; and (6) theophylline. Animals were sacrificed 1 h after treatments; hearts were isolated and analyzed. The results show that acute exercise as well as adenosine receptor agonist R-PIA significantly enhanced cardiac superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and glutathione reductase (GR) activity by 36-135% and 16-51%, respectively. Adenosine receptor agonist R-PIA significantly decreased cardiac GSSG concentration and enhanced GSH/GSSG ratio by 22 and 30%, respectively. Whereas theophylline treatment blocked the activation of antioxidant enzyme activities enhanced by acute exercise and R-PIA. Theophylline treatment significantly increased lipid peroxidation by 43% in the heart of exercised rats. The study concluded that the adenosine receptors are involved in the upregulation of cardiac antioxidant defense system and attenuation of lipid peroxidation due to acute exercise in rats.

Many individuals with cardiovascular diseases undergo periodic physical conditioning with or without medication. Therefore, this study investigated the interaction of exercise training and chronic nitroglycerin treatment on blood pressure (BP) and alterations in nitric oxide (NO), glutathione (GSH), antioxidant enzyme activities and lipid peroxidation in rats. Fisher 344 rats were divided into four groups: (1) sedentary control, (2) exercise training for 8 weeks, (3) nitroglycerin (15 mg/kg, s.c. for 8 weeks) and (4) training + nitroglycerin for 8 weeks. BP, heart rate (HR) and respiratory exchange ratio (RER) were monitored weekly for 8 weeks using tail-cuff method and oxygen/carbon dioxide analyzer, respectively. The animals were sacrificed 24 h after last treatments and plasma isolated and analyzed using HPLC, ELISA and UV-VIS spectrophotometric techniques. The results show that exercise conditioning significantly enhanced NO production (p < 0.001), GSH levels (p < 0.001), GSH/GSSG ratio (p < 0.05) and the up-regulation of the activities of catalase (CAT) (p < 0.05), glutathione peroxidase (GSH-Px) (p < 0.001), and glutathione reductase (GR) (p < 0.05), and depression of lactate levels (p < 0.001) in the plasma of the rat. These biochemical changes were accompanied by a significant increase in RER (p < 0.001) without a significant change in BP and HR. Chronic nitroglycerin administration significantly increased NO levels (p < 0.05), GSH levels (p < 0.001), superoxide dismutase (SOD) activity (p < 0.05), GST activity (p < 0.05), and decreased MDA levels (p < 0.05). These biochemical changes were accompanied by a significant decrease in BP (p < 0.05) and without any significant changes in HR and RER. Interaction of exercise training and chronic nitroglycerin treatment resulted in normalization of plasma NO, MDA, lactate levels, and CAT activity. The combination of exercise and nitroglycerin significantly enhanced GSH levels (p < 0.05), and the up-regulation of SOD (p < 0.001), GSH-Px (p < 0.05), GR (p < 0.05) and GST (p < 0.001) activities. These biochemical changes were accompanied by normalization of BP and a significant increased in RER (p < 0.001). The data suggest that the interaction of physical training and chronic nitroglycerin treatment resulted in the maintenance of BP and the up-regulation of plasma antioxidant enzyme activities and GSH levels in the rat.

Many individuals with cardiovascular diseases undergo periodic exercise conditioning with or with out medication. Therefore, this study investigated the interaction of exercise training and chronic nitric oxide synthase (NOS) inhibitor (Nitro-L-Arginine Methyl Ester, L-NAME) treatment on blood pressure and its correlation with aortic nitric oxide (NO), antioxidant defense system and oxidative stress parameters in rats. Fisher 344 rats were divided into four groups: (1) sedentary control, (2) exercise training (ET) for 8 weeks, (3) L-NAME (10 mg/kg, subcutaneous for 8 weeks) and (4) ET + L-NAME. Blood pressure (BP) was monitored weekly for 8 weeks with tail-cuff method. The animals were sacrificed 24 h after last treatments and thoracic aortic rings were isolated and analyzed. Exercise conditioning resulted in a significant increase in respiratory exchange ratio (RER), aortic NO production, NO synthase activity and inducible iNOS protein expression. Training significantly enhanced aortic GSH levels, GSH/GSSG ratio and up-regulation of aortic CuZn-SOD, Mn-SOD, catalase (CAT), glutathione peroxidase (GSH-Px) activity and protein expression and significantly decreased aortic lipid peroxidation. Chronic L-NAME administration resulted in a significant depletion of aortic NO, NOS activity, endothelial (eNOS) and iNOS protein expression, GSH level, GSH/GSSG ratio, down-regulation of aortic antioxidant enzyme activities and protein expressions. Aortic xanthine oxidase (XO) activity significantly increased with increased lipid peroxidation and protein oxidation after L-NAME administration. The biochemical changes were accompanied by increased in BP. Interaction of training and chronic NOS inhibitor treatment resulted in normalization of BP and aortic antioxidant enzyme activity and protein expression, up-regulation of aortic GSH/GSSG ratio, NO levels, Mn-SOD protein expression, depletion of GSSG, protein oxidation and lipid peroxidation. The data suggest that training attenuated the oxidative injury caused by chronic NOS inhibitor treatment by up-regulating the NO and antioxidant systems and lowering the BP in rats.

This study was designed to investigate the cisplatin-induced alteration in renal antioxidant system and the nephroprotection with ebselen. Male Wistar rats were injected with (1) vehicle control; (2) cisplatin; (3) ebselen; and (4) cisplatin plus ebselen. Rats were sacrificed three days post-treatment and plasma as well as kidney were isolated and analyzed. Plasma creatinine increased 598% following cisplatin administration alone which decreased by 158% with ebselen pretreatment. Cisplatin-treated rats showed a depletion of renal glutathione (GSH) levels (52% of control), while cisplatin plus ebselen injected rats had GSH values close to the controls. Antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities decreased 38, 75 and 62% of control, respectively, and malondialdehyde (MDA) levels increased 174% of control following cisplatin administration, which were restored to control levels after ebselen treatment. The renal platinum level did not significantly change with ebselen pretreatment. This study suggests that the protection offered by ebselen against cisplatin-induced nephrotoxicity is partly related to the sparing of antioxidant system.

Top of pageAbstract Summary: The factors associated with increased renal excretion of vasopressin (VP) were examined in the hypoxic fetus and newborn. Studies were conducted on six chronically instrumented fetal (117-136 days gestation) and seven newborn lambs (2-6-dayold). Hypoxia was produced by administration of 10% oxygen to the ewe or neonate for 30 min. This procedure caused a 50% reduction in PaO2, no significant change in pHa in either fetus or neonate and a slight fall in PaCO2. Hypoxia caused an increase in VP concentrations in plasma from 1.3 ± 0.53 to 46.4 ± 4.71 pg/ml in the fetus and from 5.9 ± 2.80 to 50.2 ± 26.68 pg/ml in the neonate. After hypoxia there was a fall in urine output from 0.27 ± 0.045 to 0.17 ± 0.046 ml/(min·kg) in the fetus and from 0.15 ± 0.033 to 0.09 ± 0.022 ml/(min·kg) in the newborn. The corresponding values for urine osmolality were the following: 168 ± 30.8 to 325 ± 30.6 mOsm/kg in the fetus and 388 ± 65.4 to 523 ±51.8 mOsm/kg in the newborn. VP concentration in urine increased from 13 ± 9.4 to a maximum of 176 ± 32.4 pg/ml after 30 min of recovery in the fetus and 39 ± 4.6 to 278 ± 132.5 pg/ml after 1 h of recovery in the newborn. These levels remained high for at least 1 h after the end of hypoxia. There was a good linear correlation between plasma VP levels and the corresponding urine levels and excretion rates in both the fetus and newborn. No correlation was found between VP urinary excretion and either osmolar excretion or GFR. These results, therefore, indicate that urinary VP levels and excretion rates can be used as a reflection of levels in plasma after hypoxia.

The response of vasoactive mediators in the neonate to a 20% fall in mean arterial blood pressure (MBP) was studied in six chronically catheterized lambs 4-7 days old, following infusion of sodium nitroprusside (SNP). No significant change in pHa, PaCO2, plasma sodium or osmolality was observed following the infusion of SNP. However, the fall in MBP from 65.3±3.90 to 53.8±2.82 mmHg (Mean ±S.E.) at the end of sixty minutes infusion was associated with the following changes in vasopressin (VP), renin activity (PRA) and catecholamine concentrations (CA) (*p

Besides classical effects on water balance and blood pressure, vasopressin has important functions in brain including modulation of behavioral processes and memory consolidation. In adult animals immunoactive VP in CSF exhibits a circadian pattern of release suggesting that the CSF may be a conduit for the effects of VP on diverse brain areas. To characterize the release of VP by the fetus, CSF was withdrawn continuously (1.0 ml/hr × 3 days) from the prechaismatic fossa of 5 chronically instrumented fetal sheep at 108 to 146 d gestation in 7 studies and plasma sampled intermittently (1.5 ml q 4h ×1 day) in 3 studies. Using a specific VP RIA,daily rhythms of VP in CSF were found for each fetus. Temporal profiles showed low levels of VP (12–25 pg/ml) during daylight alternating with high levels at night (30–45 pg/ml). Cycle length by frequency domain analysis was 22 to 24 hrs

The contribution of various factors to the release and high level of vasopressin(VP)by the fetus during hypoxic stress were examined in 27 chronically instrumented fetal lambs,118 to 135 days gestational age. They were exposed to: a)30 minutes administration of 10% O2 to the pregnant ewe (H):b) 20 minutes partial occlusion of the umbilical cord(POC); or,c) 2minutes complete occlusion of the umbilical cord(COC). The change in fetal arterial blood pressure and plasma composition were: These results indicate that osmolality is probably not a major factor in the release of VP under hypoxic stress. While hypoxemia alone does stimulate VP release, the higher VP levels following POC compared to H indicate that other factors leading to acidemia may also contribute. The rapid rise of plasma VP following 2 min. of COC during which the placental bed is temporarily excluded from the fetal circulation suggests that the placenta plays an important role in metabolism of the hormone. The large increase in BP could also be important in stimulating release of the hormone.