Ethanol, immune responses, and murine AIDS: the role of vitamin E as an immunostimulant and antioxidant

Black ginseng inhibits ethanol-induced teratogenesis in cultured mouse embryos through its effects on antioxidant activity

Fetal alcohol syndrome is caused by excessive ethanol consumption during pregnancy. We investigated the effect of black ginseng (red ginseng that is subjected to 9 cycles of 95-100 degrees C for 2-3h) on ethanol-induced teratogenesis using an in vitro whole embryo culture system. Postimplantational mouse embryos at embryonic day 8.5 were exposed to ethanol (1 microl/ml) in the presence or absence of black ginseng (1, 10, and 100 microg/ml) for 2 days, and then morphological scoring and real-time PCR analysis were carried out. In ethanol-treated embryos, the total morphological score and individual scores for flexion, heart, fore-, mid-, and hindbrains, otic, optic, and olfactory systems, branchial bars, maxillary and mandibular processes, caudal neural tube, and somites were significantly lower than the control group (p<0.05). Treatment with black ginseng improved most of the morphological scores significantly as compared to ethanol-treated embryos (p<0.05). The mRNA levels of the antioxidant enzymes cytosolic glutathione peroxidase (GPx), phospholipid hydroperoxide GPx, and selenoprotein P were significantly decreased in ethanol-treated embryos, but co-treatment with black ginseng restored the mRNA levels to those of control embryos. These results indicate that black ginseng has a protective effect on ethanol-induced teratogenesis through the augmentation of antioxidative activity in embryos.

Vitamin E and beta-carotene protect against ethanol combined with ischemia in an embryonic rat hippocampal culture model of fetal alcohol syndrome

Neurodevelopmental damage can occur as a result of in utero exposure to alcohol. Oxidative stress processes are one of many proposed mechanisms thought to contribute to nervous system dysfunction characterized in fetal alcohol syndrome (FAS). Therefore, this study examined neuroprotective effects of antioxidant supplementation during ethanol (EtOH) treatment (0, 200, 400, 800 or 1600 mg/dl) combined with concomitants of EtOH exposure: acute (2-h) ischemia (aISCH) and chronic (16-h) hypoglycemia (cHG). The antioxidants vitamin E and beta-carotene protected embryonic hippocampal cultures against 0-1600 mg/dl EtOH/aISCH/cHG treatments. In addition, neuronal viability, as measured by MTT ((3,4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide; 5 mg/ml)), was equal to untreated cultures when supplemented with vitamin E or beta-carotene at 0-800 mg/dl or 0-200 mg/dl EtOH/aISCH/cHG, respectively. These in vitro studies mirror potential in utero ethanol-exposed CNS conditions and may lead to therapeutic strategies targeted at attenuating neurodevelopmental FAS-related deficits.

The antioxidants vitamin E and beta-carotene protect against ethanol-induced neurotoxicity in embryonic rat hippocampal cultures

Fetal alcohol syndrome is characterized by numerous nervous system anomalies with the developing hippocampus being highly vulnerable. Other conditions can result from maternal ethanol consumption including oxidative stress. Critical antioxidants, such as vitamin E, can be decreased and antioxidative defenses altered. Gestational day 18 rat hippocampal cultures were exposed to ethanol ranging from 400 to 2400 mg/dl (16 h). MTT assays assessed neurotoxicity. Viability was decreased dose dependently. Supplementation with vitamin E or beta-carotene afforded neuroprotection against all ethanol concentrations. Vitamin E completely ameliorated neuronal loss following 400 and 800 mg/dl ethanol. Vitamin E increased survival to 95%, 79%, 66%, and 75% during 1600, 1800, and 2000 and 2400 mg/dl ethanol compared to nonethanol treatment. Vitamin E increased viability by 38%, 23%, 12%, and 29% at 1600, 1800, 2000, and 2400 mg/dl compared to non-vitamin E-supplemented, ethanol treatment. beta-Carotene completely ameliorated cell loss from 400 mg/dl ethanol and increased survival by 18% at 1600 mg/dl and 12% at 2000 mg/dl. This study demonstrates in vitro antioxidative neuroprotection against developmental ethanol exposure and suggests that nutritional therapies incorporating antioxidants may help protect against deleterious fetal effects from maternal alcohol abuse.

The keys of oxidative stress in acquired immune deficiency syndrome apoptosis

Apoptosis is the main cause of CD4+ T-lymphocyte depletion in acquired immune deficiency syndrome (AIDS). Various agents appear to be able to trigger apoptosis in CD4+ T cells, including viral proteins (i.e. gp120, Tat), inappropriate secretion of inflammatory cytokines by activated macrophages (i.e. tumor necrosis factor alpha) and toxins produced by opportunistic micro-organisms. Since oxidative stress can also induce apoptosis, it can be hypothesized that such a mechanism could participate in CD4+ T-cell apoptosis observed in AIDS. This correlates strongly with the observation that AIDS patients present low levels of antioxidants (i.e. superoxide dismutase-Mn, vitamin E, selenium and glutathion) most likely due to inappropriate nutrition (i.e. diets poor in antioxidants), alcohol and drug consumption, and digestive problems associated with the disease. Furthermore, the coadministration of the antiviral drug zidovudine with antioxidants increases its therapeutic potential. Finally, the following additional observations support the hypothesis that oxidative stress is involved in cell apoptosis in AIDS: (1) The depletion of the anti-apoptotic/antioxidant protein Bcl-2 in human immunodeficiency virus (HIV)-infected CD4+ cells; (2) a decrease of apoptosis in HIV-infected cells treated with antioxidants and; (3) the presence of the pro-apoptotic/pro-oxidant cytokines secreted by activated macrophages in AIDS patients. Therefore, anti-apoptotic/antioxidant strategies should be considered, alongside antiviral strategies, in order to design a more efficient therapy for AIDS in the near future.

Association between serum vitamin A and E levels and HIV-1 disease progression

OBJECTIVE

To examine the associations between serum vitamin A and E levels and risk of progression to three key outcomes in HIV-1 infection: first AIDS diagnosis, CD4+ cell decline to < 200 cells x 10(6)/l, and mortality.

DESIGN

Non-concurrent prospective study.

METHODS

Serum levels of vitamins A and E were measured at the enrollment visit of 311 HIV-seroprevalent homo-/bisexual men participating in the Baltimore/ Washington DC site of the Multicenter AIDS Cohort Study. Cox proportional hazards models were used to estimate the relative hazard of progression to each outcome over the subsequent 9 years, adjusting for several independent covariates.

RESULTS

Men in the highest quartile of serum vitamin E levels (> or = 23.5 mumol/l) showed a 34% decrease in risk of progression to AIDS compared with those in the lowest quartile [relative hazard (RH), 0.66; 95% confidence interval (CI), 0.41-1.06)]. This effect was statistically significant when comparing the highest quartile of serum vitamin E to the remainder of the cohort (RH, 0.67; 95% CI, 0.45-0.98). Associations between serum vitamin A levels and risk of progression to AIDS were less clear, but vitamin A levels were uniformly in the normal to high range (median = 2.44 mumol/l). Similar trends were observed for each vitamin with mortality as the outcome, but neither vitamin was associated with CD4+ cell decline to < 200 cells x 10(6)/l. Men who reported current use of multivitamin or single vitamin E supplements had significantly higher serum tocopherol levels than those who were not taking supplements (P = 0.0001). Serum retinol levels were unrelated to intake of multivitamin or single vitamin A supplements.

CONCLUSIONS

These data suggest that high serum levels of vitamin E may be associated with slower HIV-1 disease progression, but no relationship was observed between retinol levels and disease progression in this vitamin A-replete population.

Immunostimulating agents: what next? A review of their present and potential medical applications

Many chemical entities, either from natural sources or prepared by synthesis, are known to exert stimulating activities on various functions of the immune system, such as antibody production, resistance to infections, rejection of malignant cells, etc. In this review, the origin, chemical structures and main activities of several immunostimulants are described, with special emphasis on their present or potential medical usefulness. An attempt is made to envisage the future of this type of pharmacological agents, excluding however from the presentation the endogenous modulators of the immune system (cytokines), the production and activities of which are influenced by the immunostimulants themselves.

Immunomodulation by pycnogenol in retrovirus-infected or ethanol-fed mice

Pycnogenol is a commercial mixture of bioflavonoids that exhibits antioxidative activity. The effects of dietary pycnogenol on immune dysfunction in normal mice as well as those fed ethanol or infected with the LP-BM5 murine retrovirus were determined. The ethanol consumption and retrovirus infection caused abnormalities in the function and/or structure of a broad array of cells involved in humoral and cellular immunity. Pycnogenol enhanced in vitro IL-2 production by mitogen-stimulated splenocytes if its production was suppressed in ethanol-fed or retrovirus-infected mice. Mitogenesis of splenocytes did not show a significant change in mice treated with pycnogenol. It reduced the elevated levels of interleukin-6 produced in vitro by cells from retrovirus infected mice and IL-10 secreted by spleen cells from mice consuming ethanol. Natural killer cell cytotoxicity was increased with pycnogenol treatment.

Is alcohol consumption a cofactor in the development of acquired immunodeficiency syndrome?

Excessive alcohol (EtOH) consumption and acquired immunodeficiency syndrome (AIDS) are two major public health problems in the United States. Overwhelming evidence is showing that heavy EtOH ingestion broadly suppresses the various arms of immune response, seriously impairing the body's normal host defense to invading microbes and tumorigenesis. The onset of clinical symptoms of AIDS (low CD4+ T cells count, opportunistic infections, and tumors) is quite variable among HIV+ individuals with a mean incubation time 3-10 years following seroconversion. Because of the deleterious effects of chronic EtOH consumption on cytokine release, immune response, host defense, nutritional status, and oxidative stress, it has been believed to be a possible cofactor that could enhance the host's susceptibility to infections, and subsequently increase the rate of AIDS development. The purpose of this review is to present evidence indicating clinical disorders during EtOH ingestion in murine AIDS. These EtOH-induced abnormalities may promote a more rapid development of AIDS in HIV-infected individuals.

Chronic ethanol consumption prior to retrovirus infection alters cytokine production by thymocytes during murine AIDS

Chronic ethanol (EtOH) consumption may be a cofactor in the development of acquired immune deficiency syndrome (AIDS). As the thymus is an unique site for T cell maturation, we investigated whether thymocytes from EtOH consuming mice were more predisposed to aberrant cytokine production due to retrovirus infection. Adult female C57BL/6 mice were fed 4.5% (v/v) in liquid diet or control liquid diet without EtOH for 10 weeks. All diets contained nutrients at only the recommended daily intake level for mice. Then all mice were infected LP-BM5 retrovirus and were fed control liquid diets without EtOH. The body and thymus weights were not affected by EtOH consumption. However, thymocyte number and proliferation, which had been reduced during murine AIDS, were significantly further reduced by EtOH use. The production of IL-2 and IL-6 by thymocytes, which was lessened during retrovirus infection, were significantly further suppressed by dietary EtOH at 6 weeks postinfection, whereas levels of IL-4 and IFN-gamma by thymocytes, which were elevated during retrovirus infection, were significantly and slightly further increased by EtOH-treated mice prior to retrovirus infection, respectively. These data suggest that dietary EtOH consumption can modulate cytokine production by thymocytes, adversely affecting T cell differentiation, especially during retrovirus infection. These results provide additional evidence that EtOH consumption should be a cofactor during development of AIDS via producing altered cytokine production and then disrupting T cell differentiation.

Chronic ethanol consumption before retrovirus infection is a cofactor in the development of immune dysfunction during murine AIDS

Chronic ethanol (EtOH) consumption has been presumed to be a cofactor in the development of acquired immune deficiency syndrome (AIDS). AIDS is identified as a major public health priority in the United States, with heavy economic and social impact. In the present study, we tested this hypothesis that EtOH users are more predisposed to immunosuppression because of retrovirus infection in murine AIDS. Adult female C57BL/6 mice were fed 4.5% (v/v) in liquid diet and control diets for 10 weeks. Then all mice were infected with LP-BM5 retrovirus, causing murine AIDS, and were fed control liquid diets without EtOH. Interleukin (IL)-2 production produced by concanavalin A (Con A)-stimulated splenocytes was suppressed during murine AIDS. It was further inhibited in EtOH-fed mice compared with controls at 6 weeks postinfection, whereas decreased level of interferon-gamma during murine AIDS was not further affected in EtOH-fed mice. The levels of IL-5, IL-6, and IL-10 secreted by Con A-induced splenocytes, elevated during murine AIDS, were significantly further enhanced in EtOH-fed mice compared with controls at 6 weeks postinfection, whereas retrovirus-induced elevated release of IL-6 and tumor necrosis factor-alpha, produced by lipopolysaccharide (LPS)-stimulated splenocytes, were further increased in EtOH-fed mice compared with controls at 6 and 9 weeks postinfection, respectively. Con A- and LPS-induced splenocyte proliferation, inhibited by retrovirus infection, was significantly further suppressed in EtOH-fed mice compared with controls. These results suggest that dietary EtOH consumption before retrovirus infection aggravated progression of immune dysfunction, because it modified production of immunological regulatory cytokines and immune functions.