Vitamin E protects against polymorphonuclear leukocyte-dependent adhesion to endothelial cells

Polymorphonuclear Cell Chemotaxis and Suicidal NETosis: Simultaneous Observation Using fMLP, PMA, H7, and Live Cell Imaging

Chemotaxis and the formation of suicidal neutrophil extracellular traps (suicidal NETosis) are key functions of polymorphonuclear cells (PMNs). Neutrophil extracellular traps in particular are known to be significantly involved in the severity of inflammatory and immunological disorders such as rheumatoid arthritis and Crohn's disease. Therefore, detailed knowledge of PMNs is essential for analyzing the mechanisms involved in, and developing new therapies for, such diseases. To date, no standard method to analyze these cell activities has been established. This study used in vitro live cell imaging to simultaneously observe and analyze PMN functions. To demonstrate this, the effects of phorbol-12-myristat-13-acetat (PMA, 0.1-10 nM), N-formylmethionine-leucyl-phenylalanine (fMLP, 10 nM), and protein kinase C inhibitor 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H7) on PMN chemotaxis and suicidal NETosis were studied. PMA (1 nM-10 nM) resulted in significant concentration-dependent behavior in chemotaxis and an earlier onset of maximum oxidative burst and NET formation of up to 44%. When adding H7, PMA-triggered PMN functions were reduced, demonstrating that all three functions rely mostly on protein kinase C (PKC) activity, while PKC is not essential for fMLP-induced PMN activity. Thus, the method here described can be used to objectively quantify PMN functions and, especially through the regulation of the PKC pathway, could be useful in further clinical studies of immunological disorders.

Mitigation of Hydrochloric Acid (HCl)-Induced Lung Injury in Mice by Aerosol Therapy of Surface-Active Nanovesicles Containing Antioxidant and Anti-inflammatory Drugs

Acute lung injury leading to alveolar inflammation and surfactant dysfunction remains a medical challenge. Surface-active lipid nanovesicles of 200-250 nm size with antioxidant D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) and anti-inflammatory drug dexamethasone disodium phosphate (DXP) dual combination (Dual-NV) were developed for delivery as aerosols by nebulization in acid lung injury models. Drug deposition studies showed Dual-NV deposited ∼2.5 times more DXP compared to equivalent DXP solution. Nanovesicles are actively internalized by A549 cells through ATP- and clathrin-dependent pathways. The nanovesicles could be phagocytosed by RAW 264.7 macrophages and were nonimmunogenic and did not elicit overproduction of TNF-α, IL-1β, and IL-6. Dual-NV aerosol therapy at 200 mg/kg body weight, in HCl acid-induced lung injury in mice, markedly reduced pulmonary hemorrhage and protein leakage and improved capillary (airway) patency to ∼96%. Dual-NV aerosol therapy also significantly lowered production of inflammatory cytokine IL-1β, IL-6, and TNF-α and reduced oxidative stress by ∼95% in the injured group. Surface-active Dual-NV aerosol therapy is promising for replenishing the dysfunctional surfactant pool and mitigating inflammation and oxidative stress in lung injuries.

Rho and Reactive Oxygen Species at Crossroads of Endothelial Permeability and Inflammation

Significance: Increased endothelial permeability and inflammation are two major hallmarks of the life-threatening conditions such as acute respiratory distress syndrome and sepsis. There is a growing consensus in the field that the Rho family of small guanosine triphosphates are critical regulators of endothelial function at both physiological and pathological states. A basal level of reactive oxygen species (ROS) is essential for maintaining metabolic homeostasis, vascular tone, and angiogenesis; however, excessive ROS generation impairs endothelial function and promotes lung inflammation. In this review, we will focus on the role of Rho in control of endothelial function and also briefly discuss a nexus between ROS generation and Rho activation during endothelial dysfunction. Recent Advances: Extensive studies in the past decades have established that a wide range of barrier-disruptive and proinflammatory agonists activate the Rho pathway that, ultimately, leads to endothelial dysfunction via disruption of endothelial barrier and further escalation of inflammation. An increasing body of evidence suggests that a bidirectional interplay exists between the Rho pathway and ROS generation during endothelial dysfunction. Rac, a member of the Rho family, is directly involved in ROS production and ROS, in turn, activate RhoA, Rac, and Cdc42. Critical Issues: A precise mechanism of interaction between ROS generation and Rho activation and its impact on endothelial function needs to be elucidated. Future Directions: By employing advanced molecular techniques, the sequential cascades in the Rho-ROS crosstalk signaling axis need to be explored. The therapeutic potential of the Rho pathway inhibitors in endothelial-dysfunction associated cardiopulmonary disorders needs to be evaluated.

The rise, the fall and the renaissance of vitamin E

This review deals with the expectations of vitamin E ability of preventing or curing, as a potent antioxidant, alleged oxidative stress based ailments including cardiovascular disease, cancer, neurodegenerative diseases, cataracts, macular degeneration and more. The results obtained with clinical intervention studies have highly restricted the range of effectiveness of this vitamin. At the same time, new non-antioxidant mechanisms have been proposed. The new functions of vitamin E have been shown to affect cell signal transduction and gene expression, both in vitro and in vivo. Phosphorylation of vitamin E, which takes place in vivo, results in a molecule provided with functions that are in part stronger and in part different from those of the non-phosphorylate compound. The in vivo documented functions of vitamin E preventing the vitamin E deficiency ataxia (AVED), slowing down the progression of non-alcoholic steato-hepatitis (NASH), decreasing inflammation and potentiating the immune response are apparently based on these new molecular mechanisms. It should be stressed however that vitamin E, when present at higher concentrations in the body, should exert antioxidant properties to the extent that its chromanol ring is unprotected or un-esterified.

The α-tocopherol form of vitamin E reverses age-associated susceptibility to streptococcus pneumoniae lung infection by modulating pulmonary neutrophil recruitment

Streptococcus pneumoniae infections are an important cause of morbidity and mortality in older patients. Uncontrolled neutrophil-driven pulmonary inflammation exacerbates this disease. To test whether the α-tocopherol (α-Toc) form of vitamin E, a regulator of immunity, can modulate neutrophil responses as a preventive strategy to mitigate the age-associated decline in resistance to S. pneumoniae, young (4 mo) and old (22-24 mo) C57BL/6 mice were fed a diet containing 30-PPM (control) or 500-PPM (supplemented) α-Toc for 4 wk and intratracheally infected with S. pneumoniae. Aged mice fed a control diet were exquisitely more susceptible to S. pneumoniae than young mice. At 2 d postinfection, aged mice suffered 1000-fold higher pulmonary bacterial burden, 2.2-fold higher levels of neutrophil recruitment to the lung, and a 2.25-fold higher rate of lethal septicemia. Strikingly, α-Toc supplementation of aged mice resulted in a 1000-fold lower bacterial lung burden and full control of infection. This α-Toc-induced resistance to pneumococcal challenge was associated with a 2-fold fewer pulmonary neutrophils, a level comparable to S. pneumoniae-challenged, conventionally fed young mice. α-Toc directly inhibited neutrophil egress across epithelial cell monolayers in vitro in response to pneumococci or hepoxilin-A3, an eicosanoid required for pneumococcus-elicited neutrophil trans-epithelial migration. α-Toc altered expression of multiple epithelial and neutrophil adhesion molecules involved in migration, including CD55, CD47, CD18/CD11b, and ICAM-1. These findings suggest that α-Toc enhances resistance of aged mice to bacterial pneumonia by modulating the innate immune response, a finding that has potential clinical significance in combating infection in aged individuals through nutritional intervention.

Vitamin E in the prevention of cardiovascular disease: the importance of proper patient selection

Vitamin E is a naturally occurring fat-soluble antioxidant which has been proposed as a treatment for both primary and secondary protection against cardiovascular (CV) events. Promising data from observational epidemiological studies associating higher vitamin E dietary intake with lower risk of CV events have not been validated in randomized controlled clinical trials assessing the effect of vitamin E on CV outcomes. While the pendulum of medical opinion has swung to suggest that high dose vitamin E supplements have no place in the treatment and prevention of CV disease, new data is emerging that allows identification of a specific target population for this treatment, namely patients with diabetes mellitus and the haptoglobin genotype 2-2. This review details the scientific basis and clinical evidence related to the effect of vitamin E on CV outcomes, and the importance of proper patient selection in gaining therapeutic benefit from this intervention.

Protective Effect of Brazilian Propolis against Liver Damage with Cholestasis in Rats Treated with α-Naphthylisothiocyanate

We examined the protective effect of Brazilian propolis against liver damage with cholestasis in rats treated with α-naphthylisothiocyanate (ANIT) in comparison with that of vitamin E (VE). Rats orally received Brazilian propolis ethanol extract (BPEE) (25, 50, or 100 mg/kg), VE (250 mg/kg) or vehicle at 12 h after intraperitoneal injection of ANIT (75 mg/kg) and were killed 24 h after the injection. Vehicle-treated rats showed liver cell damage and cholestasis, judging from the levels of serum marker enzymes and components. The vehicle group had increased serum total cholesterol, triglyceride, phospholipid, and lipid peroxide levels, increased hepatic lipid peroxide, reduced glutathione, and ascorbic acid levels and myeloperoxidase activity, and decreased hepatic superoxide dismutase activity. BPEE (50 mg/kg) administered to ANIT-treated rats prevented liver cell damage and cholestasis and attenuated these serum and hepatic biochemical changes except hepatic ascorbic acid, although administered BPEE (25 or 100 mg/kg) was less effective. VE administered to ANIT-treated rats prevented liver cell damage, but not cholestasis, and attenuated increased serum lipid peroxide level, increased hepatic lipid peroxide level and myeloperoxidase activity, and decreased hepatic superoxide dismutase activity. These results indicate that BPEE protects against ANIT-induced liver damage with cholestasis in rats more effectively than VE.

The effects of α-tocopherol on oxidative damage and serum levels of Clara cell protein 16 in aspiration pneumonitis induced by bile acids

Our aim in this study is to examine the effects of α-tocopherol (AT) on rats with aspiration pneumonitis induced with bile acids (BAs). The animals were divided in to four groups, namely saline group ( n = 7), saline + AT group ( n = 7), BA group ( n = 7), and BA + AT group ( n = 7). Saline and BA groups aspirated intratracheally with 1 ml/kg saline and 1 ml/kg bile acids, respectively. AT was given at 20 mg/kg/day dosage for 7 days to the groups. AT group was given 20 mg/kg/day AT for 7 days. Malondialdehyde (MDA), Clara cell protein 16 (CC-16), catalase (CAT), superoxide dismutase (SOD), as well as peribronchial inflammatory cell infiltration, alveolar septal infiltration, alveolar edema, alveolar exudate, alveolar histiocytes, and necrosis were evaluated. The CAT activity of the BA group was significantly lower than the saline group. In the BA + AT group, there was a significant increase in SOD and CAT activities when compared with that of the BA group. The CC-16 and MDA contents in the BA group were significantly higher than in the saline group. The CC-16 and MDA levels of the BA + AT group were significantly lower than BA group. Histopathologic changes were seen in BA group, and there was a significant decrease in the BA + AT group. In conclusion, AT might be beneficial in the treatment of aspiration pneumonitis induced by BAs because AT decreased oxidative damage and resulted in a decrease in CC-16 levels.

Protective effect of Brazilian propolis against hepatic oxidative damage in rats with water-immersion restraint stress

In the present study we examined the protective effect of Brazilian propolis against hepatic oxidative damage in rats with water-immersion restraint stress (WIRS) in comparison with that of vitamin E (VE). Fasted rats orally received Brazilian green propolis ethanol extract (BPEE; 10, 50 or 100 mg/kg), VE (250 mg/kg) or vehicle at 30 min before the onset of WIRS. Exposure of vehicle-treated rats to 6 h of WIRS caused liver cell damage, judging from the levels of serum alanine aminotransferase and aspartate aminotransferease, increased hepatic lipid peroxide, NO(x) contents and myeloperoxidase activity, and decreased hepatic non-protein SH, ascorbic acid contents and superoxide dismutase activity. Preadministration of BPEE (50 or 100 mg/kg) or VE to the stressed rats protected against the hepatic damage and attenuated the increased hepatic lipid peroxide and NO(x) contents and myeloperoxidase activity and the decreased hepatic non-protein SH and ascorbic acid contents and superoxide dismutase activity. These protective effects of BPEE (50 mg/kg) were greater than those of BPEE (100 mg/kg) and were almost equal to those of VE. These results indicate that BPEE protects against hepatic oxidative damage in rats exposed to WIRS possibly through its antioxidant and antiinflammatory properties such as VE.

Effects of grape seed extract, vitamin C, and vitamin e on ethanol- and aspirin-induced ulcers

Effects of GSE and vitamins C and E on aspirin- and ethanol-induced gastric ulcer and associated increases of lipid peroxidation in rats were compared. Two experiments were conducted. Rats were randomized into eight groups: a negative control and seven groups that received aspirin or ethanol for ulcer induction: one positive control (vehicle) and six with VC, VE, or GSE (25 and 250 mg/kg). Ulcer indexes and gastric levels of malondialdehyde (MDA) were quantified. VC, VE, and GSE (25 and 250 mg/kg) decreased aspirin, and ethanol-induced ulcers and MDA values compared with positive control group. The magnitude of aspirin ulcer reduction was comparable for all treatments, and MDA decrease with GSE was higher than with VC and tended to be greater, albeit none significantly, than with VE. GSE was more effective than VC and VE for lowering the ethanol ulcers, while the decrease of MDA levels with GSE was greater than with VC, but comparable to that achieved with VE. GSE protected against ethanol-induced gastric ulcers more effectively than VC or VE, while its protection against aspirin ulcers was comparable for all treatments. GSE produced the greatest reductions of gastric MDA in both models.

Vitamin E has a dual effect of anti-inflammatory and antioxidant activities in acetic acid-induced ulcerative colitis in rats

BACKGROUND

Increased free radical production, decreased antioxidant capacity and excessive inflammation are well-known features in the pathogenesis of inflammatory bowel disease. Vitamin E is a powerful antioxidant and a scavenger of hydroxyl radicals, and it has been shown to have anti-inflammatory activities in tissues. We investigated the effects of vitamin E on inflammatory activities using an acetic acid (AA)-induced ulcerative colitis model in rats.

METHODS

Wistar rats were divided into 4 groups. Acetic acid was given to 2 groups of animals to induce colitis while the other 2 groups received saline intrarectally. One AA-induced colitis group and 1 control group received vitamin E (30 U/kg/d) intraperitoneally and the pair groups received saline. After 4 days, we evaluated colonic changes biochemically by measuring proinflammatory cytokine levels in tissue homogenates and by histopathologic examination.

RESULTS

Acetic acid caused colonic mucosal injury, whereas vitamin E administration suppressed these changes in the AA-induced colitis group (p < 0.001). Administration of AA resulted in increased levels of tumour necrosis factor-α, interleukin-1β, interleukin-6, myeloperoxidase and malondialdehyde, and decreased levels of glutathione and superoxide dismutase; vitamin E reversed these effects (all p < 0.001).

CONCLUSION

Our study proposes that vitamin E is an effective anti-inflammatory and antioxidant and may be a promising therapeutic option for ulcerative colitis.

Vitamin E has a dual effect of anti-inflammatory and antioxidant activities in acetic acid-induced ulcerative colitis in rats

BACKGROUND

Increased free radical production, decreased antioxidant capacity and excessive inflammation are well-known features in the pathogenesis of inflammatory bowel disease. Vitamin E is a powerful antioxidant and a scavenger of hydroxyl radicals, and it has been shown to have anti-inflammatory activities in tissues. We investigated the effects of vitamin E on inflammatory activities using an acetic acid (AA)-induced ulcerative colitis model in rats.

METHODS

Wistar rats were divided into 4 groups. Acetic acid was given to 2 groups of animals to induce colitis while the other 2 groups received saline intrarectally. One AA-induced colitis group and 1 control group received vitamin E (30 U/kg/d) intraperitoneally and the pair groups received saline. After 4 days, we evaluated colonic changes biochemically by measuring proinflammatory cytokine levels in tissue homogenates and by histopathologic examination.

RESULTS

Acetic acid caused colonic mucosal injury, whereas vitamin E administration suppressed these changes in the AA-induced colitis group (p < 0.001). Administration of AA resulted in increased levels of tumour necrosis factor-α, interleukin-1β, interleukin-6, myeloperoxidase and malondialdehyde, and decreased levels of glutathione and superoxide dismutase; vitamin E reversed these effects (all p < 0.001).

CONCLUSION

Our study proposes that vitamin E is an effective anti-inflammatory and antioxidant and may be a promising therapeutic option for ulcerative colitis.

Antioxidant vitamins and their use in preventing cardiovascular disease

Atherosclerosis remains one of the leading causes of death in Western populations. Subsequent to the discovery that oxidative stress plays a pivotal role in the development and progression of atherosclerosis, vitamins C and E, along with other antioxidants, were studied as potential therapies for the disease. However, while in vitro and in vivo studies showed promising antiatherogenic effects for vitamins C and E, clinical trials in which patients were given high doses of vitamin E or C showed no benefit and even possible harm. This review will attempt to summarize the known mechanistic data regarding the biochemical effects of vitamins C and E and their relevance to atherosclerosis, and offer an explanation for the failure of clinical trials to show that supplementation with these vitamins provides any benefit when given indiscriminately. We provide one example of how pharmacogenomics may be used to identify a sub-population which may indeed benefit from antioxidant supplementation.

Vitamin E protects against stress-induced gastric mucosal lesions in rats more effectively than vitamin C

In this study, we examined the protective effects of vitamin E (VE) against gastric mucosal lesions induced by water immersion restraint stress (WIRS) in rats in comparison with that of vitamin C (VC). The gastric mucosa of rats with 6 h of WIRS showed lesions with bleeding, decrease in nonprotein SH, VC, VE, and adherent mucus concentrations and constitutive nitric oxide synthase activity, and increase in lipid peroxide and NOx (nitrite/nitrate) concentrations and myeloperoxidase, xanthine oxidase, and inducible nitric oxide synthase activities. Either VE (0.05 or 0.5 mmol/kg) or VC (0.5 or 1.5 mmol/kg) was orally administered to rats with 6 h of WIRS just before the onset of the stress. Both doses of pre-administered VE prevented gastric mucosal lesion development and attenuated all these changes in gastric mucosal components and enzymes studied, whereas only the higher dose of pre-administered VC suppressed the changes in all parameters studied. These results indicate that orally administered VE protects against WIRS-induced gastric mucosal lesions in rats more effectively than orally administered VC. These results also suggest that the administered VE protects against gastric mucosal lesions in rats with WIRS through its antioxidant and anti-inflammatory actions in the gastric mucosa in the same way as the administered VC.

Effects of genistein on oxidative injury in endothelial cells

The aim of this study was to test the hypothesis that genistein protects vascular endothelial cells against the pro-atherosclerotic stressor, oxidized low-density lipoprotein (ox-LDL), by inducing antioxidant enzymes and preventing apoptosis. Human umbilical cord-derived endothelial cells (ECV 304) were incubated with genistein (10-100 micromol/L), the radical scavenging antioxidant vitamin E (alpha-tocopherol, 50 micromol/L), or vehicle for 24 h and then were incubated with ox-LDL for an additional 24 h. Subsequently, antioxidant enzyme activities, lipid peroxidation, adhesion to monocytes, cell morphology, viability and apoptotic index were assessed. Ox-LDL decreased superoxide dismutase and glutathione peroxidase activities in endothelial cells and caused lipid peroxidation, adhesion to monocytes, morphological injury and apoptosis (p<0.05). These effects were prevented by vitamin E and dose-dependently by genistein (p<0.05). Further, this effect of genistein is associated with maintenance of antioxidant enzyme activities and inhibition of lipid peroxidation.

Apoptosis and macrophage infiltration occur simultaneously and present a potential sign of muscle injury in skeletal muscle of nutritionally compromised, early post-hatch turkeys

Physical stress and malnutrition may cause elimination of myonuclei and produce inflammatory response in muscle. The objective of this study was to histochemically determine the association of apoptosis and/or macrophage infiltration with changes in muscle satellite cell mitotic activity in pectoralis thoracicus muscle of early post-hatch turkey toms. Feed-deprived birds and birds provided with three different levels of crude protein and amino acids (0.88 NRC, 1.00 NRC, and 1.12 NRC) were used in this model. The number of apoptotic nuclei was significantly elevated (P<0.05) and presence of macrophage infiltration was readily detectable in feed-deprived and 0.88 NRC treatment groups 72 h and 96 h post-hatch suggesting potential muscle injury and/or muscle remodeling. The number of apoptotic nuclei was the same (P>0.05), and there was no detectable macrophage infiltration present in birds placed on 1.00 NRC and 1.12 NRC diet 72 h, 96 h, and 120 h post-hatch. At 120 h post-hatch, feed-deprived and 0.88 NRC birds were characterized by no detectable levels of macrophage infiltration and a significant drop (P<0.05) in apoptotic nuclei. Understanding mechanisms that correlate early nutrition with skeletal muscle growth and development may present a useful tool in optimizing muscle health and improving meat quality and yield.

Rectal administration of d-alpha tocopherol for active ulcerative colitis: A preliminary report

AIM: To investigate the anti-oxidant and anti-neutrophil recruitment effects of rectal d-alpha (d-α) tocopherol administration on mild and moderately active ulcerative colitis (UC).

METHODS: Fifteen patients with mild and moderately active ulcerative colitis were enrolled in an open-label study of d-α tocopherol enema (8000 U/d) for 12 wk. All patients were receiving concomitant therapy with 5-aminosalicylic acid derivatives (5-ASA) and/or immunomodulator medications. Endoscopic evaluation was performed at baseline and after 4th and 12th weeks. Disease activity was measured with the Mayo disease activity index (DAI) and remission was defined as DAI of ≤ 2 with no blood in stool. Clinical response was defined as a DAI reduction of ≥ 2.

RESULTS: At the end of 12th week, the average DAI score significantly decreased compared to the beginning of the study (2.3 ± 0.37 vs 8 ± 0.48, P < 0.0001). One patient was withdrawn after 3 wk for being unavailable to follow-up. On the 4th week of therapy, 12 patients showed clinical response, 3 of whom (21.4%) achieving remission. After 12 wk, all 14 patients responded clinically to the therapy and remission was induced in 9 of them (64%). No patient reported adverse events or was hospitalized due to worsened disease activity.

CONCLUSION: This preliminary report suggests that rectal d-α tocopherol may represent a novel therapy for mild and moderately active UC. The observed results might be due to the anti-inflammatory and anti-oxidative properties of vitamin E.

The intervention of antioxidant therapy on platelet adhesion and immunomodulation in experimental physical stress

During effort overstress the reactive oxygen species act chiefly on unsaturated lipids, inducing the formation of certain peroxidation products. We have investigated malondialdehide (MDA), platelet adhesion index, and immunological activation parameters during effort overstress and administration of vitamins E and C. Biochemical measurements were performed on erythrocytes and heart homogenate. In the vitamin E supplemented group, the platelet adhesion index was constantly correlated with the MDA level (p < 0.001). There is a protecting effect concerning the oxidative stress in animals pretreated with vitamin E and C, which is expressed through the diminution of the MDA quantity both in the erythrocyte and in the heart. The physical effort required by swimming led to a decrease in the NBT test values and in the activity of the serum complement. The steady administration of vitamin E in the effort overstress, due to its antioxidant properties, causes the progressive decrease in peroxidation and platelet adhesion.

Effects of rosiglitazone on native low-density-lipoprotein-induced respiratory burst in circulating monocytes and on the leukocyte-endothelial interaction in cholesterol-fed rats

Low-density lipoprotein (LDL) has been implicated in the initiation and progression of atherosclerotic vascular disease. But whether LDL can elicit similar effects in the microcirculation remain unexplored. To approach this issue, the hypothesis that LDL promotes oxidative stress in monocytes and results in microvascular inflammation was tested. Native LDL was capable of stimulating respiratory burst in rat monocytes, and this was blocked by BAPTA, cytochalasin B, apocynin, and diphenyliodonium. In monocytes from rats on a high-cholesterol (4%) diet, increased intracellular calcium, actin polymerization, respiratory burst, and surface CD18 expression were found. Concurrently, leukocyte-endothelial interaction was enhanced in the cremaster microcirculation. Rosiglitazone, an insulin-sensitizing agent with antiinflammatory properties, was found to suppress native-LDL-induced actin polymerization and respiratory burst in monocytes. It also improved leukocytes activation and leukocyte-endothelial interaction due to the high cholesterol intake. Hence, native LDL stimulation of monocytes contributed to hypercholesterolemia-associated microvascular inflammation, which could be treated by rosiglitazone.

Vitamin E down-modulates mitogen-activated protein kinases, nuclear factor-kappaB and inflammatory responses in lung epithelial cells

The airway epithelium plays an active role in acute lung inflammation by producing chemotactic factors and by expressing cell adhesion molecules involved in the migration of leucocytes to extravascular spaces. We have reported previously that neutrophil migration to airways can be down-modulated by exogenously administered vitamin E (alpha-tocopherol). The mechanism for this effect is not well understood, however. The action of alpha-tocopherol was investigated in human alveolar type II and bronchial epithelial cells stimulated with tumour necrosis factor-alpha. Treatment of alveolar epithelial cells with alpha-tocopherol resulted in down-regulated cell surface expression of intercellular adhesion molecule-1 (ICAM-1). On bronchial epithelial cells, both ICAM-1 and vascular adhesion molecule-1 were decreased, leading to diminished adherence of leucocytes to the cells. The production of the neutrophil chemoattractant interleukin-8 was attenuated in both alveolar and bronchial cells. These effects were preceded by reduced activation of the mitogen-activated protein kinases (MAPK), extracellular signal-regulated kinase (ERK1/2) and p38, as well as down-regulation of nuclear factor-kappaB. Comparing the effects of alpha-tocopherol with that of specific inhibitors of MAPK and protein kinase C (PKC) revealed that effects appear to be partly independent of PKC inhibition. These results implicate the anti-inflammatory action of alpha-tocopherol in addition to its anti-oxidant properties.

Preventive effect of Shigyaku-san on progression of acute gastric mucosal lesions induced by compound 48/80, a mast cell degranulator, in rats

The study examined whether Shigyaku-san (Si-Ni-San) extract (TJ-35), a traditional Kampo medicine, prevents acute gastric mucosal lesion progression in rats treated once with compound 48/80 (C48/80). Rats treated with C48/80 (0.75 mg/kg body weight, i.p.) received TJ-35 (0.15, 0.35 or 0.75 g/kg body weight, p.o.) 0.5 h after the treatment at which time gastric mucosal lesions appeared. At 0.5 h after C48/80 treatment, the gastric mucosa of the treated rats had increased myeloperoxidase (an index of neutrophil infiltration) and xanthine oxidase activities and thiobarbituric acid reactive substances (an index of lipid peroxidation) content. At 3 h after C48/80 treatment, the gastric mucosa of the treated rats showed progressive lesions and further increases in myeloperoxidase and xanthine oxidase activities and thiobarbituric acid reactive substances content and decreases in vitamin E, ascorbic acid and adherent mucus contents and Se-glutathione peroxidase activity. Post-administered TJ-35 attenuated all these changes found at 3 h after C48/80 treatment dose-dependently. These results indicate that TJ-35 prevents the progression of C48/80-induced acute gastric mucosal lesions in rats possibly by attenuating enhanced neutrophil infiltration, enhanced lipid peroxidation associated with decreased vitamin E and ascorbic acid contents and Se-glutathione peroxidase activity, and destruction of the defensive barrier in the gastric mucosa.

α-Tocopherol protects against α-naphthylisothiocyanate-induced hepatotoxicity in rats less effectively than melatonin

The protective effect of alpha-tocopherol (alpha-Toc), which exerts antioxidant and anti-inflammatory actions, against alpha-naphthylisothiocyanate (ANIT)-induced hepatotoxicity in rats was compared with that of melatonin because orally administered melatonin is known to protect against ANIT-induced hepatotoxicity in rats through its antioxidant and anti-inflammatory actions. Rats intoxicated once with ANIT (75 mg/kg, intraperitoneal (i.p.)) showed liver cell damage and biliary cell damage with cholestasis at 24 h, but not 12 h, after intoxication. ANIT-intoxicated rats received alpha-Toc (100 or 250 mg/kg) or melatonin (100 mg/kg) orally at 12 h after intoxication. The alpha-Toc administration protected against liver cell damage in ANIT-intoxicated rats, while the melatonin administration protected against both liver cell damage and biliary cell damage with cholestasis. ANIT-intoxicated rats had increased hepatic lipid peroxide concentration and myeloperoxidase activity at 12 and 24 h after intoxication. ANIT-intoxicated rats also had increased serum alpha-Toc and non-esterified fatty acid (NEFA) concentrations at 12 and 24 h after intoxication and increased serum triglyceride and total cholesterol concentrations at 24h. The administration of alpha-Toc to ANIT-intoxicated rats increased the hepatic alpha-Toc concentration with further increase in the serum alpha-Toc concentration and attenuated the increased hepatic lipid peroxide concentration and myeloperoxidase activity and serum NEFA concentration at 24 h after intoxication. The melatonin administration did not affect the hepatic alpha-Toc concentration but attenuated the increased hepatic lipid peroxide concentration and myeloperoxidase activity and serum alpha-Toc, NEFA, triglyceride, and total cholesterol concentrations at 24 h after ANIT intoxication. These results indicate that orally administered alpha-Toc protects against ANIT-induced hepatotoxicity in rats possibly through its antioxidant and anti-inflammatory actions less effectively than orally administered melatonin.

Effect of oral vitamin E administration on acute gastric mucosal lesion progression in rats treated with compound 48/80, a mast cell degranulator

The effect of oral vitamin E administration on acute gastric mucosal lesion progression was examined in rats treated once with compound 48/80 (C48/80) (0.75 mg/kg, i.p.) in comparison with that of subcutaneously administered superoxide dismutase (SOD) plus catalase (CAT). Vitamin E (50, 100 or 250 mg/kg) administered at 0.5 h after C48/80 treatment reduced progressive gastric mucosal lesions at 3 h after the treatment dose-dependently, like SOD plus CAT administered at the same time point. The gastric mucosa of C48/80-treated rats had decreased Se-glutathione peroxidase activity and vitamin E, ascorbic acid, and hexosamine contents and increased myeloperoxidase and xanthine oxidase activities and thiobarbituric acid reactive substances content at 3 h after the treatment. Administered vitamin E attenuated all these changes found at 3 h after C48/80 treatment dose-dependently, like administered SOD plus CAT. C48/80-treated rats administered with vitamin E (100 or 250 mg/kg) had higher gastric mucosal vitamin E content than C48/80-untreated rats. Neither administered vitamin E nor SOD plus CAT had any effect on the increases in serum serotonin and histamine concentrations and the decrease in gastric mucosal blood flow found at 3 h after C48/80 treatment. In the gastric mucosa of C48/80-untreated rats administered with vitamin E, thiobarbituric acid reactive substances content decreased with an increase in vitamin E content. These results indicate that orally administered vitamin E prevents acute gastric mucosal lesion progression in C48/80-treated rats possibly by suppressing oxidative stress, neutrophil infiltration, and mucus depletion in the gastric mucosa like administered SOD plus CAT.

Influence of vitamin E on gastric mucosal injury induced by Helicobacter pylori infection

We investigated the effect of vitamin E on gastric mucosal injury induced by Helicobacter pylori (H. pylori) infection. Male Mongolian gerbils were divided into 4 groups (normal group without H. pylori infection, vitamin E-deficient, -sufficient and -supplemented groups with H. pylori infection). Following oral inoculation with H. pylori (ATCC43504 2 x 10(8) CFU), animals were fed diets alpha-tocopherol 2 mg/100 g diet in the normal and vitamin E-sufficient groups and alpha-tocopherol 0.1 mg/100 g and 50 mg/100 g in the vitamin E-deficient and -supplemented groups, respectively, for 24 weeks. Chronic gastritis was detected in all gerbils inoculated H. pylori. Gastric ulcer was detected in 2 of 7 gerbils only in the vitamin E-deficient group. In the vitamin E-deficient group, myeloperoxidase activity and mouse keratinocyte derived chemokine (KC) in gastric mucosa was significantly higher than in the vitamin E supplemented group. Subsequently, in an in vitro study expression of CD11b/CD18 on neutrophils was enhanced by H. pylori water extract. This effect was suppressed in a dose dependent manner by the addition of alpha-tocopherol. These results suggest that vitamin E has a protective effect on gastric mucosal injury induced by H. pylori infection in gerbils, through the inhibition of accumulation of activated neutrophils.

Vitamin E supplementation suppresses macrophage accumulation and endothelial cell expression of adhesion molecules in the aorta of hypercholesterolemic rabbits

Suppression of cell adhesion molecule expression and macrophage accumulation by the endothelium is believed to play an important role in preventing the development of atherosclerosis. Earlier, we have shown that in vitro supplementation of human aortic endothelial cells with Vitamin E dose-dependently reduced expression of adhesion molecules and monocyte adhesion. Here, we report the in vivo down-regulation of endothelial cell adhesion molecules expression and macrophage accumulation in the aortas of hypercholesterolemic rabbits supplemented with Vitamin E. To this end, New Zealand White rabbits were fed a semi-purified diet containing 30 (control) or 1000 IU/kg Vitamin E. After 4 weeks, both groups' diets were switched to an atherogenic diet (0.3% cholesterol, 9% hydrogenated coconut oil, and 1% corn oil) containing the respective levels of Vitamin E and fed for 2, 4, and 6 weeks. Vitamin E supplemented rabbits had significantly higher levels of Vitamin E in their plasma and aortas. Frozen aorta sections were fixed and stained by an avidin-biotin complex method using Rb2/3 and Rb1/9 monoclonal antibodies against rabbit ICAM-1 and VCAM-1, respectively, and with RAM-11 for macrophage and von Willebrand factor for endothelial cells, followed by staining with secondary antibodies and counterstaining and evaluation under the microscope. At 6 weeks on atherogenic diet treatment, a trend (P = 0.08) toward a lower score of ICAM-1 expression by endothelial cells was observed in the aorta of Vitamin E treated rabbits compared to the control. However, a decrease in the score of VCAM-1 expression by endothelial cells in Vitamin E treated rabbits did not reach to a statistical significance. At 4 and 6 weeks on atherogenic diet, Vitamin E supplementation also significantly (P = 0.003) inhibited the accumulation of macrophages in the aorta. These results support the concept that down-regulation of adhesion molecule expression and suppression of monocyte/macrophage activation by Vitamin E in vivo is one of the potential mechanisms by which Vitamin E may suppress the development of aortic lesions in a rabbit model of atherosclerosis.

Anti-atherosclerotic effects of vitamin E--myth or reality?

Atherosclerosis and its complications such as coronary heart disease, myocardial infarction and stroke are the leading causes of death in the developed world. High blood pressure, diabetes, smoking and a diet high in cholesterol and lipids clearly increase the likelihood of premature atherosclerosis, albeit other factors, such as the individual genetic makeup, may play an additional role. Several epidemiological studies and intervention trials have been performed with vitamin E, and some of them showed that it prevents atherosclerosis. For a long time, vitamin E was assumed to act by decreasing the oxidation of LDL, a key step in atherosclerosis initiation. However, at the cellular level, vitamin E acts by inhibition of smooth muscle cell proliferation, platelet aggregation, monocyte adhesion, oxLDL uptake and cytokine production, all reactions implied in the progression of atherosclerosis. Recent research revealed that these effects are not the result of the antioxidant activity of vitamin E, but rather of precise molecular actions of this compound. It is assumed that specific interactions of vitamin E with enzymes and proteins are at the basis of its non-antioxidant effects. Vitamin E influences the activity of several enzymes (e.g. PKC, PP2A, COX-2, 5-lipooxygenase, nitric oxide synthase, NADPH-oxidase, superoxide dismutase, phopholipase A2) and modulates the expression of genes that are involved in atherosclerosis (e.g. scavenger receptors, integrins, selectins, cytokines, cyclins). These interactions promise to reveal the biological properties of vitamin E and allow designing better strategies for the protection against atherosclerosis progression.

Strenuous, acute exercise affects reciprocal modulation of platelet and polymorphonuclear leukocyte activities under shear flow in men

Vigorous exercise transiently increases the risk of primary cardiac arrest. The reciprocal modulation of platelet and polymorphonuclear leukocyte (PMN) activities is important in the pathogenesis of thrombosis. This study investigates how strenuous, acute exercise affects platelet-PMN reciprocal modulation by closely examining 18 sedentary men who exercised strenuously on a bicycle ergometer. Shear-induced platelet activation, PMN interaction with surface-adherent platelets under shear flow, and PMN-dependent inhibition of platelet activation were measured both before and immediately after exercise. Analytical results can be summarized as follows: (i) shear-induced platelet adhesion on fibronectin-coated surface as well as ADP-induced release of platelet soluble P-selectin release and elevation of [Ca2+]i significantly increases after strenuous exercise; (ii) strenuous exercise is associated with higher velocity and percentage of rolling PMNs and lower numbers of PMNs remaining bound to surface-adherent platelets under shear flow than at rest; (iii) PMN-dependent inhibition of platelet [Ca2+]i elevation and soluble P-selectin release after strenuous exercise is much greater than that at rest; and (iv) strenuous exercise increases PMN-derived nitric oxide metabolite level and reduces oxidized low-density lipoprotein-promoted interaction between platelets and PMNs. Therefore, we conclude that platelet activity may be sensitized by strenuous exercise. However, strenuous exercise can also simultaneously enhance the antiplatelet effect of PMNs. The finding provides a new insight into the negative feedback of PMNs against exercise-evoked platelet-related thrombotic risk.

Six-year effect of combined vitamin C and E supplementation on atherosclerotic progression: the Antioxidant Supplementation in Atherosclerosis Prevention (ASAP) Study

BACKGROUND

Self-selected supplementation of vitamin E has been associated with reduced coronary events and atherosclerotic progression, but the evidence from clinical trials is controversial. In the first 3 years of the ASAP trial, the supplementation with 136 IU of vitamin E plus 250 mg of slow-release vitamin C twice daily slowed down the progression of carotid atherosclerosis in men but not women. This article examines the 6-year effect of supplementation on common carotid artery (CCA) intima-media thickness (IMT).

METHODS AND RESULTS

The subjects were 520 smoking and nonsmoking men and postmenopausal women aged 45 to 69 years with serum cholesterol > or =5.0 mmol/L (193 mg/dL), 440 (84.6%) of whom completed the study. Atherosclerotic progression was assessed ultrasonographically. In covariance analysis in both sexes, supplementation reduced the main study outcome, the slope of mean CCA-IMT, by 26% (95% CI, 5 to 46, P=0.014), in men by 33% (95% CI, 4 to 62, P=0.024) and in women by 14% (not significant). In both sexes combined, the average annual increase of the mean CCA-IMT was 0.014 mm in the unsupplemented and 0.010 mm in the supplemented group (25% treatment effect, 95% CI, 2 to 49, P=0.034). In men, this treatment effect was 37% (95 CI, 4 to 69, P=0.028). The effect was larger in subjects with either low baseline plasma vitamin C levels or CCA plaques. Vitamin E had no effect on HDL cholesterol.

CONCLUSIONS

These data replicate our 3-year findings confirming that the supplementation with combination of vitamin E and slow-release vitamin C slows down atherosclerotic progression in hypercholesterolemic persons.

Vitamin E reduces transendothelial migration of neutrophils and prevents lung injury in endotoxin-induced airway inflammation

We investigated the pharmacologic effects of the antioxidant Vitamin E (alpha-tocopherol [alpha-toc]) in airway inflammation induced by inhaled endotoxin. A preparation of alpha-toc incorporated in liposomes was administered intraperitoneally in mice 1 h after exposure of aerosolized endotoxin. Injection of 50 mg alpha-toc/kg significantly decreased the number of neutrophils in airspaces and prevented lung injury, monitored both as decreased lactate dehydrogenase activity in airways and reduced lung edema when compared with animals treated with plain liposomes. Immunofluorescence staining of lung tissue revealed that treatment with alpha-toc decreased the number of neutrophils in lung interstitium, whereas the number in lung blood vessels and peripheral blood did not differ between mice treated with alpha-toc and control mice. Our results indicate that alpha-toc downmodulates the migration of neutrophils across the endothelial barrier, but in contrast to strong anti-inflammatory drugs such as corticosteroids, without inhibition of transcription factors involved in the early inflammatory response (nuclear factor-kappaB/activator protein-1). Neither was the endotoxin-induced expression of proinflammatory cytokines in lung tissue downregulated. Treatment with a combination of alpha-toc and a suboptimal dose of 0.5 mg/kg dexamethasone enhanced the effect, suggesting that alpha-toc, in combination with low doses of corticosteroids, might be effective for therapeutic treatment of acute lung injury.

Alpha-tocopherol prevents apoptosis of vascular endothelial cells via a mechanism exceeding that of mere antioxidation

Alpha-tocopherol has been reported to exert an anti-atherogenesis effect. We attempted to clarify the effect of alpha-tocopherol-both as an antioxidant and as a nonantioxidant--on apoptosis induced by oxidized low-density lipoprotein (LDL) or oxysterols. Oxidized LDL and oxysterols induced necrosis and/or apoptosis of vascular endothelial cells. The induction of apoptosis was associated with increased caspase-3 activity and the generation of intracellular reactive oxygen species, both the effects of which were attenuated by alpha-tocopherol. Apoptosis was also decreased by beta-tocopherol or intracellular radical scavengers, but these suppressive effects were less than those of alpha-tocopherol. Neither beta-tocopherol nor the scavengers had pronounced effect on caspase-3 activity, but each of them decreased the generation of reactive oxygen species to the same extent as alpha-tocopherol. Our study suggests that alpha-Toc protects against apoptosis not only by scavenging reactive oxygen species, but also by inhibiting caspase activity, which means that its activity may exceed that of a mere antioxidant.

Inhibitory effect of a novel water-soluble vitamin E derivative on atherosclerosis in rabbits

A novel vitamin E derivative that is freely soluble in water, 2-(alpha-D-glucopyranosyl)methyl-2,5,7,8-tetramethylchroman-6-ol (TMG), was evaluated for ability to inhibit development of atherosclerosis in Watanabe heritable hyperlipidemic (WHHL) rabbits or cholesterol-loaded New Zealand White rabbits. Although TMG rapidly entered the circulation blood after oral administration, the blood TMG concentration remained low, while neither TMG nor its metabolites appeared in the low-density lipoprotein (LDL) fraction. TMG did not decrease serum total cholesterol and the various lipoprotein-associated cholesterol fractions (very LDL-, or high-density lipoprotein- (HDL) cholesterol). TMG reduced the serum concentration of thiobarbituric acid-reactive substances (TBARS; an index of lipid peroxidation) in cholesterol-loaded rabbits but not WHHL rabbits. Nonetheless, TMG inhibited aortic atherosclerosis as effectively as probucol in both models. Our results indicate that TMG opposes progression of atherosclerosis not only by preventing oxidation of LDL, but also by presently unknown mechanisms. Even an antioxidant with no uptake by LDL apparently can inhibit development of atherosclerosis despite a very low serum concentration.

The 80th anniversary of vitamin E: beyond its antioxidant properties

Molecules provided with an antioxidant function may have additional properties, the latter being sometimes of greater importance than the former. In the last ten years, alpha-tocopherol has revealed precise cellular functions, some of which are independent of its antioxidant/radical scavenging ability. At the posttranslational level, alpha-tocopherol inhibits protein kinase C and 5-lipoxygenase and activates protein phosphatase 2A and diacylglycerol kinase. Some genes (CD36, alpha-TTP, alpha-tropomyosin, and collagenase) are affected by alpha-tocopherol at the transcriptional level. alpha-Tocopherol also induces inhibition of cell proliferation, platelet aggregation and monocyte adhesion. These effects are unrelated to the antioxidant activity of vitamin E, but rather are believed to be a result of specific interactions of vitamin E with components of the cell, e. g. proteins, enzymes and membranes. This review focuses on novel non-antioxidant functions of alpha-tocopherol and discusses the possibility that many of the effects previously attributed to the antioxidant functions can also be explained by non-antioxidant mechanisms.

Gene expression induced by BO-653, probucol and BHQ in human endothelial cells

2, 3-Dihydro-5-hydroxy-2, 2-dipentyl-4, 6-di-tert-butylbenzofuran (BO-653) and probucol, which act as radical scavenging antioxidants, were developed as anti-atherosclerotic medicines. In order to investigate the effect of these antioxidants on cell functions, we analyzed their ability to regulate gene expression in cultured human umbilical vein endothelial cells (HUVECs) using an oligonucleotide chip. Among 6,416 genes, 17 genes including those encoding mitochondrial proteins and proteins related to oxidative stress response were induced more than 3 fold by BO-653, probucol and tert-butylated hydroquinone (BHO). On the other hand, genes of three subunits of proteasome (PSMA2, PSMA3, PSMA4) were down-regulated by these antioxidants. A gene of cytochrome P-450 1A1 isozyme, a drug-metabolizing phase I enzyme, was expressed only by BHQ treatment. These results suggested that anti-atherogenic antioxidants affected gene expression in HUVECs by which they might regulate cell functions against oxidative stress.

Vitamin E: protective role of a Janus molecule

Since the discovery of vitamin E in 1922, its deficiency has been associated with various disorders, particularly atherosclerosis, ischemic heart disease, and the development of different types of cancer. A neurological syndrome associated with vitamin E deficiency resembling Friedreich ataxia has also been described. Whereas epidemiological studies have indicated the role of vitamin E in preventing the progression of atherosclerosis and cancer, intervention trials have produced contradictory results, indicating strong protection in some cases and no significant effect in others. Although it is commonly believed that phenolic compounds like vitamin E exert only a protective role against free radical damage, antioxidant molecules can exert other biological functions. For instance, the antioxidant activity of 17-beta-estradiol is not related to its role in determining secondary sexual characters, and the antioxidant capacity of all-trans-retinal is distinguished from its role in rhodopsin and vision. Thus, it is not unusual that alpha-tocopherol (the most active form of vitamin E) has properties independent of its antioxidant/radical scavenging ability. The Roman god Janus, shown in ancient coins as having two faces in one body, inspired the designation of 'Janus molecules' for these substances. The new biochemical face of vitamin E was first described in 1991, with an inhibitory effect on cell proliferation and protein kinase C activity. After a decade, this nonantioxidant role of vitamin E is well established, as confirmed by authoritative studies of signal transduction and gene regulation. More recently, a tocopherol binding protein with possible receptor function has been discovered. Despite such important developments in understanding the molecular mechanism and the targets of vitamin E, its new Janus face is not fully elucidated. Greater knowledge of the molecular events related to vitamin E will help in selecting the parameters for clinical intervention studies such as population type, dose response effects, and possible synergism with other compounds.

Erythrocyte, but not plasma, vitamin E concentration is associated with carotid intima-media thickening in asymptomatic men at risk for cardiovascular disease

Epidemiological data regarding the preventive role of vitamin E in the pathogenesis of atherosclerosis have yielded conflicting results, possibly because endpoints considered were clinical events but not detection of atherosclerosis per se. Otherwise, it has been suggested that the measure of the erythrocyte alpha-tocopherol level may be more suitable to assess the human tocopherol status than its plasma level. We investigated the association between early atherosclerosis in superficial arteries assessed noninvasively and the alpha-tocopherol status in 261 asymptomatic men at risk for cardiovascular disease. alpha-Tocopherol concentrations in plasma, HDL, and erythrocytes were determined using a reverse-phase HPLC method. Detection of carotid plaques and measure of carotid intima-media thickness (IMT) were performed using high-resolution B-mode ultrasonography. The main result of this study is the observation of a negative correlation (P<0.01) between carotid IMT and erythrocyte alpha-tocopherol concentration, independently of conventional cardiovascular risk factors, whereas no such association has been found with plasma (total or HDL) alpha-tocopherol concentrations. No association has been evidenced between alpha-tocopherol concentrations and carotid plaques. These results emphasize the primary protective role of vitamin E in the early phases of atherosclerosis and the significance of the erythrocyte alpha-tocopherol concentration as a marker of atherosclerosis.

The effect of alpha-tocopherol on monocyte proatherogenic activity

Atherosclerosis is the leading cause of morbidity and mortality in Westernized populations. The monocyte is a crucial cell in the genesis of the atherosclerotic lesion and is present during all stages of atherosclerosis. alpha-Tocopherol (AT) is the most active component of the vitamin E family and is the principal and most potent lipid-soluble antioxidant in plasma and LDL. With regard to monocyte function, AT supplementation (1200 IU/d) has been shown to decrease release of reactive oxygen species, lipid oxidation, release of cytokines such as interleukin-1ss (IL-1ss) and tumor necrosis factor-alpha (TNF-alpha) and decrease adhesion of monocytes to human endothelium. The mechanism of inhibition of superoxide and lipid oxidation by monocytes appears to be via inhibition of protein kinase C (PKC), the decrease in IL-1ss and TNF-alpha release by inhibition of 5-lipoxygenase and the inhibition of monocyte-endothelial cell adhesion via decrease in adhesion molecules on monocytes, CD11b and VLA-4 and by decreasing DNA-binding activity of nuclear transcription factor kappaB. Thus, in addition to the decrease in oxidative stress resulting from AT supplementation, as evidenced by decreased F(2)-isoprostanes and LDL oxidizability, AT is anti-inflammatory and exerts beneficial antiatherogenic effects on cells crucial in atherogenesis such as monocytes.

Diverse functions of antioxidants

All biological organisms have developed a defense system against oxidative stress, which is comprised of many kinds of antioxidants. Antioxidants are classified by function into four categories; preventive antioxidants; radical scavenging antioxidants; repair and de novo antioxidants; and adaptation. Radical scavenging antioxidants have the greatest advantage. Although the activities of radical scavenging antioxidant are determined by several factors, their chemical structure is of key importance. Furthermore, radical scavenging antioxidants have been explored to have a novel function by which they regulate gene expression of cell.

Antioxidant Supplementation in Atherosclerosis Prevention (ASAP) study: a randomized trial of the effect of vitamins E and C on 3-year progression of carotid atherosclerosis

OBJECTIVES

To study the efficacy of vitamin E and C supplementation on the progression of carotid atherosclerosis, hypothesizing an enhanced preventive effect in men and in smokers and synergism between vitamins.

DESIGN AND SUBJECTS

Double-masked two-by-two factorial trial, randomization in four strata (by gender and smoking status) to receive twice daily either 91 mg (136 IU) of d-alpha-tocopherol, 250 mg of slow-release vitamin C, a combination of these or placebo for three years. A randomized sample of 520 smoking and nonsmoking men and postmenopausal women aged 45-69 years with serum cholesterol >/= 5.0 mmol L-1 were studied.

SETTING

The population of the city of Kuopio in Eastern Finland.

INTERVENTION

Twice daily either a special formulation of 91 mg of d-alpha-tocopherol, 250 mg of slow-release vitamin C, a combination of these (CellaVie(R)) or placebo for three years.

MEASUREMENTS

Atherosclerotic progression, defined as the linear regression slope of ultrasonographically assessed common carotid artery mean intima-media thickness (IMT), was calculated over semi-annual assessments.

RESULTS

The average increase of the mean IMT was 0.020 mm year-1 amongst men randomized to placebo and 0.018 mm year-1 in vitamin E, 0.017 mm year-1 in vitamin C and 0.011 mm year-1 in the vitamin combination group (P = 0.008 for E + C vs. placebo). The respective means in women were 0.016, 0.015, 0.017 and 0.016 mm year-1. The proportion of men with progression was reduced by 74% (95% CI 36-89%, P = 0.003) by supplementation with the formulation containing both vitamins, as compared with placebo.

CONCLUSIONS

Our study shows that a combined supplementation with reasonable doses of both vitamin E and slow-release vitamin C can retard the progression of common carotid atherosclerosis in men. This may imply benefits with regard to other atherosclerosis-based events.

Potential antiatherogenic mechanisms of ascorbate (vitamin C) and alpha-tocopherol (vitamin E)

The premise that oxidative stress, among several other factors, plays an important role in atherogenesis implies that the development and progression of atherosclerosis can be inhibited by antioxidants. In this minireview we discuss several mechanisms by which the antioxidants ascorbate (vitamin C) and alpha-tocopherol (vitamin E) may protect against atherosclerosis. These mechanisms include inhibition of LDL oxidation and inhibition of leukocyte adhesion to the endothelium and vascular endothelial dysfunction. Overall, ascorbate appears to be more effective than alpha-tocopherol in mitigating these pathophysiological processes, most likely as a result of its abilities to effectively scavenge a wide range of reactive oxygen and nitrogen species and to regenerate alpha-tocopherol, and possibly tetrahydrobiopterin, from its radical species. In contrast, alpha-tocopherol can act either as an antioxidant or a pro-oxidant to inhibit or facilitate, respectively, lipid peroxidation in LDL. However, this pro-oxidant activity of alpha-tocopherol is prevented by ascorbate acting as a coantioxidant. Therefore, an optimum vitamin C intake or body status may help protect against atherosclerosis and its clinical sequelae, whereas vitamin E may only be effective in combination with vitamin C.

Specific cellular responses to alpha-tocopherol

In the last 10 years precise cellular functions of alpha-tocopherol, some of which are independent of its antioxidant/radical-scavenging ability, have been revealed. Absorption of alpha-tocopherol from the gut is a selective process. Other tocopherols are not absorbed or are absorbed to a lesser extent. At the post-translational level, alpha-tocopherol inhibits protein kinase C and 5-lipoxygenase and activates protein phosphatase 2A and diacylglycerol kinase. Some genes [platelet glycoprotein IV/thrombospondin receptor/class B scavenger receptor (CD36), alpha-tocopherol transfer protein (alpha-TTP), alpha-tropomyosin, connective tissue growth factor and collagenase] are affected by alpha-tocopherol at the transcriptional level. alpha-Tocopherol also inhibits cell proliferation, platelet aggregation, monocyte adhesion and the oxygen burst in neutrophils. Other antioxidants, such as beta-tocopherol and probucol, do not mimic these effects, suggesting a nonantioxidant, alpha-tocopherol-specific molecular mechanism.

Phenolic antioxidants: a rationale for design and evaluation of novel antioxidant drug for atherosclerosis

With increasing evidence that shows the involvement of active oxygen and nitrogen species in a variety of disorders, cancer, and aging, the role of antioxidant against oxidative stress has received renewed attention. In this review article, a rationale for design of lipophilic, radical-scavenging antioxidant is presented and the potency of a novel antioxidant, 2,3-dihydro-5-hydroxy-2,2-dipentyl-4, 6-di-tert-butylbenzofuran (BO-653), as an inhibitor of LDL oxidation was evaluated by considering various factors such as reactivity toward radicals, localization, and mobility in the lipoprotein, and fate of its radical. The anti-atherogenic activity of BO-653 was compared with those of alpha-tocopherol, probucol, and its metabolites. Furthermore, a novel function of phenolic antioxidants such as cell regulation and induction of phase II defense antioxidants are also discussed.

Lipid oxidation products in cell signaling

The recent research on the impact that oxidative changes of biolipids could have in pathophysiology serves to explain how free radical-driven reactions not only are considered as mere toxicologic events, but also modulators of cell activity and function. Oxidatively modified low-density lipoproteins are known to affect various cellular processes by modulating various molecular pathways and signaling nuclear transcription. Among the lipid oxidation products detectable in ox-LDLs, and also in the atherosclerotic plaques, 4-hydroxynonenal has been widely investigated. This aldehyde was shown to upregulate AP-1 transcription factor, signaling through the MAP kinase pathway, with eventual nuclear localization and induction of a series of genes. Further, oxidation products of cholesterol and cholesterol esters, in ox-LDL are of similar interest, especially in relation to the pathogenesis of fibrosclerotic lesions of the arterial wall.

Vitamin E: non-antioxidant roles

Vitamin E was originally considered a dietary factor of animal nutrition especially important for normal reproduction. The significance of vitamin E has been subsequently proven as a radical chain breaking antioxidant that can protect the integrity of tissues and play an important role in life processes. More recently alpha-tocopherol has been found to possess functions that are independent of its antioxidant/radical scavenging ability. Absorption in the body is alpha-tocopherol selective and other tocopherols are not absorbed or are absorbed to a lesser extent. Furthermore, pro-oxidant effects have been attributed to tocopherols as well as an anti-nitrating action. Non-antioxidant and non-pro-oxidant molecular mechanisms of tocopherols have been also described that are produced by alpha-tocopherol and not by beta-tocopherol. alpha-Tocopherol specific inhibitory effects have been seen on protein kinase C, on the growth of certain cells and on the transcription of some genes (CD36, and collagenase). Activation events have been seen on the protein phosphatase PP2A and on the expression of other genes (alpha-tropomyosin and Connective Tissue Growth Factor). Non-antioxidant molecular mechanisms have been also described for gamma-tocopherol, delta-tocopherol and tocotrienols.

A new mechanism for anti-inflammatory actions of proton pump inhibitors--inhibitory effects on neutrophil-endothelial cell interactions

BACKGROUND

Neutrophil-endothelial cell interactions mediated by adhesion molecules may be involved in gastric mucosal inflammation associated with Helicobacter pylori or nonsteroidal anti-inflammatory drugs.

AIM

To investigate the effects of proton pump inhibitors and histamine-2 receptor antagonists (HRA) on neutrophil-endothelial cell adhesive interactions induced by H. pylori water extract (HPE) or interleukin-1beta (IL-1beta).

METHODS

Human peripheral neutrophils and umbilical vein endothelial cells were incubated with either proton pump inhibitors (lansoprazole and omeprazole) or HRA (famotidine and ranitidine). Neutrophil surface expression of CD11b and CD18 and endothelial cell intercellular adhesion molecule-1 (ICAM-1) and vascular adhesion molecule-1 (VCAM-1) were assessed by flow cytometry and an enzyme immunoassay, respectively. Neutrophil adherence was defined as the ratio of exogenous neutrophils that adhered to the endothelial monolayers.

RESULTS

The expression of CD11b and CD18 on neutrophils and neutrophil-dependent adhesion to endothelial cells elicited by HPE were inhibited by lansoprazole and omeprazole at clinical relevant doses, and the expression of ICAM-1 and VCAM-1 on endothelial cells and endothelial-dependent neutrophil adherence induced by IL-1beta were also inhibited by lansoprazole and omeprazole at similar doses. Famotidine and ranitidine had no effect on neutrophil-endothelial cell interactions.

CONCLUSIONS

These results indicate that proton pump inhibitors can attenuate neutrophil adherence to endothelial cells via inhibiting the expression of adhesion molecules, suggesting that proton pump inhibitors may have anti-inflammatory activity.

Alpha-tocopherol protects against monocyte Mac-1 (CD11b/CD18) expression and Mac-1-dependent adhesion to endothelial cells induced by oxidized low-density lipoprotein

Alpha-tocopherol supplementation is reported to protect against cardiovascular disease and to influence cells involved in atherogenesis, such as monocytes. Interactions between monocytes and vascular endothelial cells occur early in atherogenesis, and adhesion is mediated by integrins. We evaluated the effects of alpha-tocopherol on expression of Mac-1 (CD11b/CD18) by monocytes after stimulation with oxidized low-density lipoprotein (LDL), which is implicated as a potent chemotactic agent in atherogenesis. Incubation of whole blood with oxidized LDL (100 microg/ml) increased Mac-1 expression on monocytes, and preincubation with alpha-tocopherol reduced this upregulation in a concentration dependent manner. In another experiment, whole blood was obtained from healthy adult volunteers after 10 days of alpha-tocopherol administration (600 mg/day) and was incubated with oxidized LDL (100 microg/ml). There was a decrease in the upregulation of Mac-1 compared with that measured before administration. Adherence of oxidized LDL-stimulated monocytes to human umbilical vein endothelial cells was reduced by pretreatment with alpha-tocopherol, and was also inhibited by an anti-CD18 monoclonal antibody. Experiments with protein kinase C inhibitors suggested that reduction of Mac-1 upregulation by alpha-tocopherol was secondary to a decrease of protein kinase C activity. In conclusion, alpha-tocopherol suppressed the upregulation of Mac-1 expression on monocytes by oxidized LDL.

Inhibitory effects of vitamin E on endothelial-dependent adhesive interactions with leukocytes induced by oxidized low density lipoprotein

Leukocyte-endothelial cell interactions, which are mediated by various adhesion molecules, are a crucial event in inflammatory reactions including atherosclerosis. Alpha-tocopherol (alpha-Toc) has been used for protection and therapy of vascular diseases because of its antioxidant activity. The objective of the present study was to determine effect of alpha-Toc on endothelial-dependent adhesive interactions with leukocytes elicited by oxidized low density lipoprotein (oxLDL). Incubation of HUVEC with oxLDL (100 microg/mL) increased expression of proteins and messenger RNA of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) on enzyme immunoassay and northern blotting assay; pretreatment with alpha-Toc reduced in a dose dependent manner. Adherence of polymorphonuclear leukocytes (PMN) or mononuclear leukocytes (MNC) to oxLDL-activated HUVEC was much increased compared with that to unstimulated HUVEC. Treatment of HUVEC with alpha-Toc, monoclonal antibody to ICAM-1 or VCAM-1 inhibited adherence of PMN or MNC in a dose dependent manner. These results suggest that alpha-Toc works as anti-atherogenic agent through inhibiting endothelial-dependent adhesive interactions with leukocytes induced by oxLDL.