Vitamin E Supplementation Decreases Autoantibodies to Oxidized Lipid-Protein Complexes

A novel alkaloid antioxidant, Boldine and synthetic antioxidant, reduced form of RU486, inhibit the oxidation of LDL in-vitro and atherosclerosis in vivo in LDLR(-/-) mice

A corollary to the oxidation hypothesis of atherosclerosis is that the consumption of antioxidants is beneficial. However, the literature is divided in support of this conclusion. In this study, Boldine, an alkaloid of Peumus boldus and reduced form of RU486, was tested for their antioxidant potency both in, in vitro oxidation system and in mouse models. Boldine decreased the ex-vivo oxidation of low-density lipoprotein (LDL). Two different in vivo studies were performed to study the effect of these compounds on the atherosclerotic lesion formation in LDLR(-/-) mice. In study I, three groups of LDLR(-/-) mice (N = 12 each) were fed an atherogenic diet. Group 1 was given vehicle and group 2 and 3 were given 1mg of Boldine or Red RU per day for 12 weeks. In study II, two groups of LDLR(-/-) mice N = 10 each) were fed an atherogenic diet. Group 1 was given vehicle and group 2 was given 5mg of Boldine per day. The results indicated that there was a decrease in lesion formation reaching a 40% reduction due to Boldine and 45% reduction by Red RU compared to controls. The in vivo tolerance of Boldine in humans (has been used as an herbal medicine in other diseases) should make it an attractive alternative to Vitamin E.

Profiling of human cytokines in healthy individuals with vitamin E supplementation by antibody array

Previously, we demonstrated that vitamin E supplementation decreases autoantibodies to oxidized lipid-protein complexes (J. Med. Food 1 (2000) 247). Utilizing an in vitro modeling system, we also demonstrated that vitamin E blocks the tumor promotion process in liver epithelial cells (Carcinogenesis 20 (1999) 485 and Mol. Carcinog. 30 (2001) 209). To investigate the molecular mechanisms of vitamin E function, we developed a human cytokine array system that is capable of detecting the expression of 35 cytokines simultaneously. Using this new technology, we analyzed the potential vitamin E-regulated cytokines in vitamin E supplementation individuals. The cytokine arrays showed that expression of several cytokines, particularly monocyte chemoattractant protein-1 (MCP-1), was profoundly reduced in vitamin E supplementation individuals. Moreover, addition of vitamin E to several cultured cells significantly down-regulated the expression of MCP-1. Our results suggested that MCP-1 may be one of the most important targets of antioxidant vitamin E. To the best of our knowledge, this is the first report describing the down-regulation of MCP-1 in vitamin E supplementation in vivo.

Increased myeloperoxidase and lipid peroxide-modified protein in gynecological malignancies

Oxidative stress has been implicated in several diseases, including cancer. Oxidants induce oncogenes and their products associated with cell growth. Even though epidemiological studies implicate oxidants in promoting cancer, there is still a lack of in vivo evidence for the same. In this study, we measured the levels of myeloperoxidase (MPO), an enzyme associated with oxidation and autoantibodies to lipid peroxide-modified protein (LOOH-RSA), in the plasma of subjects with gynecological cancers. The gynecological cancer subjects (n = 201) had higher plasma MPO and LOOH-RSA levels compared with control subjects (n = 60). Immunohistochemical analysis of tissues revealed that immunostaining for MPO and LOOH-RSA was higher in cancer tissues compared with controls. The staining was specific to cell types and not ubiquitously present. Neutrophils, monocytes/macrophages, and natural killer cells have been proposed to play a role in cancer promotion and progression. This study proposes a role for oxidative stress and especially MPO in cancer.

Alpha-tocopherol and probucol reduce autoantibody titer to MDA-LDL in hypercholesterolemic rabbits

We considered the hypothesis that antioxidant supplementation that increases aortic antioxidant concentrations would reduce autoantibody titer to MDA-LDL, a measure that may indicate in vivo oxidation. We assessed autoantibody titer to MDA-LDL in rabbits before and after 5 months of treatment with a nutritionally adequate hypercholesterolemic diet alone (control) or supplemented with synthetic alpha-tocopherol or probucol. Aortic cholesterol and antioxidants were assessed at the end of treatment. alpha-Tocopherol supplementation increased the ratio of aortic alpha-tocopherol to cholesterol by 20-30-fold, while probucol supplementation increased the ratio of aortic probucol to cholesterol to 4-13 micromol/mol. Before treatment, MDA-LDL autoantibody titer averaged 5.09 +/- 0.24 with no difference among groups (p =.53 by ANOVA). However, after treatment, autoantibody titers differed among groups (p <.03 by ANOVA). Autoantibody titers were similar in rabbits supplemented with alpha-tocopherol and probucol (3.69 +/- 0.21 and 3.73 +/- 0.48, respectively, p = 0.81), and 26% (p <.009) lower in antioxidant supplemented rabbits than unsupplemented hypercholesterolemic rabbits (5.03 +/- 0.47). There was an inverse J relationship between autoantibody titer after treatment and aortic alpha-tocopherol/cholesterol and probucol/cholesterol, with minimum values for autoantibody titers above 8-10 micromol antioxidant/mmol cholesterol. The results of this study are consistent with inhibition of in vivo intra-aortic oxidation when aortic alpha-tocopherol or probucol exceed 8-10 micro;mol/mmol cholesterol.

Did the antioxidant trials fail to validate the oxidation hypothesis?

Most clinical trials on antioxidants using vitamin E or beta-carotene have failed to note any significant change in cardiovascular endpoints. The results of these studies have been interpreted as a setback for the oxidation hypothesis. An analysis of the hypothesis and the trials, however, points out major misconceptions about the hypothesis and unjustified outcome expectations. Wrong selection of patient population, endpoints that are incompatible with the hypothesis, poor choice of antioxidants, and lack of inclusion of biochemical markers of oxidative stress and markers of vascular response are some of the contributors to the "failure" of these trials.

Detection of multiple proteins in an antibody-based protein microarray system

A new antibody-based protein array assay is described. This assay combines the advantages of the specificity of enzyme-linked immunosorbent assays (ELISA), sensitivity of enhanced chemiluminescence (ECL) and high-throughput of microspot. In this system, the capture proteins, either antibodies or antigens are spotted onto membranes in an array format. Biological samples are then incubated with membranes. After antigens or antibodies in the samples bind to their corresponding targets and unbound proteins are washed away, the membranes are exposed to Horseradish Peroxidase (HRP)-conjugated antibody(ies). The signals are finally visualized with ECL system. Experiments demonstrate that multiple cytokines and antibodies can be simultaneously detected using this new approach. The procedure is so simple that no sophisticated equipment is required. The concept should be able to be extended to develop a high-throughput protein array system. Future applications of this new approach include direct protein expression profiling, immunological disease diagnostics and discovery of new biomarkers.