Increased Vitamin E Content in the Lungs of Chronic Cigarette-Smoked Rats

Vitamin E as an antioxidant of the lung: mechanisms of vitamin E delivery to alveolar type II cells

Oxidants play an important role in the development of acute and chronic lung injuries. Alveolar surfactant is the first target of air-borne oxidants. Surfactant contains, besides dipalmitoyl phosphatidylcholine, cholesterol and polyunsaturated phospholipids that play an important functional role. Therefore, vitamin E could be important for protecting surfactant lipids against oxidation and subsequent lung injury. Alveolar type II cells play a central role in synthesis and secretion of surfactant lipids and also supplement the surfactant with vitamin E during intracellular assembly. High density lipoprotein (HDL) is the primary source of vitamin E for type II cells. The uptake of vitamin E by specific lipid transfer is mediated by at least three HDL-specific receptors (scavenger receptor BI, membrane dipeptidase, and HDL-binding protein-2). In addition, cubilin and megalin mediate in a cooperative manner HDL-holoparticle uptake by alveolar type II cells. A temporary vitamin E deficiency induces a reversible change of the expression of pro- and antiinflammatory markers and of markers defining apoptosis, and reduces surfactant lipid synthesis in alveolar type II cells. These metabolic changes of type II cells may prime the lung to develop clinically manifest injury in response to an additional insult, e.g., hyperoxia.

Micronutrient antioxidants in gastric mucosa and serum in patients with gastritis and gastric ulcer: does Helicobacter pylori infection affect the mucosal levels?

Free radicals (FRs) play an important role in the pathogenesis of gastroduodenal mucosal inflammation, peptic ulcer disease, and probably even gastric cancer. Various micronutrients protect the gastric mucosa by scavenging FRs. Only limited data is available regarding the concentration of micronutrients in the gastric mucosa in patients with gastritis and peptic ulcer disease. Our aim was to analyze micronutrient antioxidant concentrations in the antral mucosa in patients with gastritis and gastric ulcer and to determine the influence of Helicobacter pylori infection on gastric mucosal antioxidants in patients with gastritis and gastric ulcer. Patients who underwent upper endoscopy for evaluation of dyspepsia were included in the study. Ascorbic acid, alpha-tocopherol, alpha-carotene, beta-carotene, total carotenoids, lutein, cryptoxanthin, and lycopene levels were measured in the sera and antral mucosal biopsies in these patients. The diagnosis of H. pylori was confirmed by histology, urease test (CLO) and serology. Patients with negative endoscopic findings and normal histology and no H. pylori infection served as controls. In patients with gastritis, alpha-tocopherol levels were reduced in serum and mucosa irrespective of H. pylori status, whereas carotenoids and ascorbic acid levels were similar to controls. However, in patients with gastric ulcer, serum and mucosal levels of all micronutrient antioxidants were markedly decreased compared with both controls and patients with gastritis. The degree of depletion of antioxidants was similar in patients with either H. pylori-induced or nonsteroidal antiinflammatory drug (NSAID)-induced ulcers. Patients with gastric ulcer have very low gastric antioxidant concentrations compared to patients with gastritis and normal mucosa. This depletion in antioxidants seems to be a nonspecific response and was not related to H. pylori infection.

Vitamin E concentrations in the human stomach and duodenum--correlation with Helicobacter pylori infection

BACKGROUND

Vitamin E (alpha-tocopherol) is an important endogenous antioxidant and may also act as an anticarcinogen.

AIM

To determine the vitamin E status of subjects with, and without, gastroduodenal inflammation and Helicobacter pylori infection.

SUBJECTS

36 patients undergoing routine gastroscopy for investigation of dyspepsia.

METHODS

High performance liquid chromatography with fluorometric detection was used to determine alpha-tocopherol values.

RESULTS

In H pylori negative subjects with normal gastroduodenal histology (n = 11) median alpha-tocopherol values (ng/mg tissue weight) were significantly higher in the corpus (16.4, interquartile range (IQR) 8.9-22.6) than in the antrum (3.0, IQR 2.6-6.7, p = 0.001) or duodenum (6.7, IQR 2.5-8.4, p = 0.001). H pylori infection (n = 19) was associated with a reduction in the corpus alpha-tocopherol values (median 8.3, IQR 4.9-13.7, p < 0.05) but there was no significant change in the antral concentrations although this was the main site of inflammation and neutrophil activity. Duodenal alpha-tocopherol values were not significantly changed in the presence of duodenitis or gastric H pylori infection. alpha-Tocopherol was not detected in the gastric juice of any of the subjects. Plasma alpha-tocopherol concentrations in the H pylori negative subjects (median 10.4 mg/l, IQR 7.2-11.9) were not significantly different to the values in the H pylori positive subjects (median 11.1 mg/l, IQR 7.6-12.7).

CONCLUSIONS

Concentrations of alpha-tocopherol in H pylori negative subjects are higher in the corpus than in the antrum or duodenum. In the presence of predominantly antral H pylori infection and neutrophil activity the major change seen is a reduction in corpus alpha-tocopherol values while antral concentrations are maintained. These findings may reflect a mobilisation of antioxidant defences to the sites of maximal inflammation in the stomach.

Deficiency in antioxidant factors in patients with alcohol-related chronic pancreatitis

Free radicals have been suspected to play a role in the pathogenicity of alcohol-related chronic pancreatitis. The aim of this study was to determine the status of several antioxidant parameters in these patients and examine the factors that are likely to influence them. Thirty-five subjects (23 males and 12 females, mean age 48 +/- 8 years) with disease proven by endoscopic pancreatography and 14 healthy controls (6 males and 8 females, mean age 44 +/- 7 years) were included in the study. Biochemical antioxidant parameters included: selenium, zinc, and copper levels in plasma; glutathione peroxidase in plasma and erythrocytes; plasma malondialdehyde concentrations assessed by thiobarbituric acid reactants; and serum vitamin E and A levels. Selenium and vitamin E oral intake was assessed by a five-day diet analysis. Hemoglobin (130 +/- 16 vs 143 +/- 15 g/liter), vitamin E (8 +/- 5 vs 16 +/- 9 mg/liter), vitamin A (30 +/- 11 vs 49 +/- 12 micrograms/dl), selenium (54 +/- 20 vs 87 +/- 11 micrograms/liter), and plasma glutathione peroxidase (903 +/- 313 vs 1326 +/- 168 units/liter) were significantly lower in patients than in controls (P < 0.05). In contrast, white blood cell count, C-reactive protein, and plasma copper levels were significantly higher in patients than in controls. Cholesterol, triglycerides, iron, ferritin, total proteins, zinc, and malondialdehyde were not different. Vitamin E was lower in patients with steatorrhea, while vitamin A was lower in patients with concomitant diabetes mellitus. Dietary intakes were not different between patients and controls. In conclusion, patients with alcohol-related chronic pancreatitis have low blood levels in many antioxidant factors. Dietary intakes of some of them (selenium and vitamin E) are adequate, however. Such deficiencies are secondary to pancreatic insufficiency and probably to increased requirements related to enhanced oxidative stress.

Cerulein-induced acute pancreatitis diminished vitamin E concentration in plasma and increased in the pancreas

Redistribution of vitamin E in the rat body was studied during acute pancreatitis induced by two intraperitoneal doses of cerulein 40 micrograms/kg of body weight at 1-hr intervals. Hyperamylasemia (2064 +/- 521 vs 6419 +/- 129 U/dL) and pancreatic edema (pancreatic water content, 71 +/- 1.2% vs 78 +/- 2%) were observed. In this model the increased level of lipid soluble fluorophore was also observed (274 +/- 18 vs 120 +/- 9.0 relative fluorescence per g dry wt). Parallel with these changes was a decrease in the level of vitamin E in the serum and an increase in the pancreas. The concentration of vitamin E in the pancreas after 6 h was 162 +/- 8.5 ng/mg dry mass vs 128.1 +/- 6.1 ng/mg dry mass in control animals. The effect of heparin on vitamin E redistribution induced by acute pancreatitis was also investigated. It was found that heparin at a dose of 100 U/kg body mass prevents the drop of the vitamin E level in the serum as well as the increases in the concentration in the pancreas tissue. It was concluded that acute pancreatitis induced redistribution of vitamin E in the rat body. Moreover, we studied the effects of heparin treatment on oxidative stress in the pancreas tissue. Acute pancreatitis caused an increase in lipofuscin accumulation, and a decrease in protein sulfhydryl groups in citrate synthetase (CS) and in malate dehydrogenase (MDH) activity. Heparin treatment that protected vitamin E accumulation in the pancreas tissue did not influence the changes in the level of lipofuscin and proteins sulfhydryl.(ABSTRACT TRUNCATED AT 250 WORDS)

Vitamin E, pulmonary functions, and phagocyte-mediated oxidative stress in smokers and nonsmokers

Relationships among the plasma levels of vitamin E (VE), the numbers and prooxidative activities of circulating phagocytes, serum alpha-1-protease inhibitor (API), and pulmonary functions were investigated in 83 asymptomatic male cigarette smokers and 65 nonsmoking controls. Plasma levels of VE, of cholesterol, and of API were measured using high performance liquid chromatography, spectrophotometry, and nephelometry, respectively, whereas reactive oxidant (ROS) generation by activated blood phagocytes was measured using a whole blood luciginen-enhanced chemiluminescence method. Smoking was associated with significantly increased circulating neutrophil counts (p 0.0001), serum API (p 0.0001) and phagocyte-derived ROS-generation (p 0.0001), and decreased spirometric values (FEV1: p 0.0138 and FEF25-75: p 0.0654). Plasma VE and cholesterol levels were not significantly different between smokers and nonsmokers. However, in smokers both plasma VE and cholesterol correlated significantly and positively with serum API (r 0.24, p 0.03 and r 0.30, p 0.005, respectively), neutrophil counts (r 0.24, p 0.03 and r 0.25, p 0.03, respectively), and phagocyte-derived ROS-generation (r 0.32, p 0.003 and r 0.32, p 0.003, respectively), and significantly and inversely with FEV1 (r -0.23, p 0.03 and r -0.22, p 0.04, respectively) and FEF25-75 (r -0.32, p 0.003 and r -0.26, p 0.02, respectively). In nonsmokers plasma VE, but not cholesterol, was positively correlated with FEV1 (r 0.34, p 0.007) and FEF25-75 (r 0.40, p 0.001). The results suggest that VE protects the lungs of both smokers and nonsmokers and may act as a mobilizable antioxidant in response to smoking-induced oxidative stress.

Exercise, oxidative stress, and antioxidants: a review

Elemental and gaseous oxygen presents a conundrum in that it is simultaneously essential for and potentially destructive to human life. Traditionally the ability to consume large volumes of oxygen has been assumed to be totally beneficial to the organism. In the past 10 years it has become clear that oxygen radicals are generated even during normal resting metabolism. Nevertheless, such radicals are usually of no appreciable threat since a wide array of protective biochemical systems exist. However, under certain circumstances aerobic exercise may increase free radical production to a level that overwhelms those defenses. A broad array of nutrients such as vitamin C, vitamin E, beta-carotene, and so forth are known to suppress such radical events. This paper reviews the status of our knowledge relative to the potential benefits of nutritional modification in augmenting the organism's normal defense against harmful radical chemistry.

Cigarette smoking and oxidative damage in the lung

Cigarette smoke contains a large variety of compounds, including many oxidants and free radicals that are capable of initiating or promotes oxidative damage. Also, oxidative damage may result from reactive oxygen species generated by the increased and activated phagocytes following cigarette smoking. In vitro studies are generally supportive of the hypothesis that cigarette smoke can initiate or promote oxidative damage. However, information obtained from in vivo studies is inconclusive. Contrary to expectations, the levels of lipid peroxidation products were found to be decreased or unchanged in the lungs of chronically smoked rats. Metabolic adaptation, such as accumulation of vitamin E in the lung, and increased activities of superoxide dismutase in alveolar macrophages and pulmonary tissues of chronically smoked animals may enable smoked subjects to counteract oxidative stress and to resist further damage to smoke exposure. However, it is also possible that the metabolic adaptation may be secondary to inflammatory response and injury repair process following smoking exposure. More studies are needed to better understand the role of oxidative damage in the etiology of smoking-related disorders.

Vitamin E and oxidative stress

Oxidative stress can result from or be enhanced by a large variety of conditions, including nutritional imbalance, exposure to chemical and physical agents in the environment, strenuous physical activities, injury, and hereditary disorders. While many enzymes and compounds are involved in protecting cells from the adverse effects of oxidative stress, vitamin E occupies an important and unique position in the overall antioxidant defense. The antioxidant function of vitamin E is closely related to the status of many dietary components. Vitamin E-depleted animals are generally more susceptible to the adverse effects of environmental agents than supplemented animals. Also, vitamin E supplementation is beneficial to certain groups of the population. However, supplementing vitamin E in experimental subjects maintained on a nutritionally adequate diet does not always provide additional protection. Differential metabolic responses in various organs and differences in experimental conditions often contribute in the discrepancies in the literature. The lack of clear evidence for the occurrence of lipid peroxidation or antioxidant function of vitamin E in vivo can be attributed partly to the presence of active pathways for metabolizing hydroperoxides, aldehydes, and other oxidation products. Specific and sensitive techniques for measuring lipid peroxidation products in biological systems are essential for understanding the role of free radical-induced lipid peroxidation in tissue damage and antioxidant function of vitamin E in vivo.