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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vitamin A and other retinoids have profound effects on macrophage differentiation and function. Such effects could alter interactions between HIV and tissue macrophages, a principal target cell and reservoir for virus during HIV disease. Indeed, retinoids are used to treat various symptoms associated with HIV infection. We show that levels of virus replication in monocytes cultured 7 days before and continuously after HIV infection in 1 to 10 microM retinoic acid were 10- to 20-fold greater than those of control cells. No direct toxicity (detachment from substrate or cell death) was evident in infected or control monocytes treated with less than or equal to 10 microM retinoic acid. Maximum effects of retinoic acid (50% maximum effect was at 0.8 +/- 0.1 microM) required 5 to 7 days treatment before infection and persisted without additional treatment through more than 4 wk. RT activity in cultures of retinoic acid-treated monocytes reached maximum levels much earlier than those of control cultures, but the minimum tissue culture infectious doses for retinoic acid-treated and untreated monocytes were comparable. Retinoic acid treatment did not affect susceptibility of monocytes to HIV infection. Further, the frequency of infected cells in retinoic acid-treated and control cultures were also comparable: about 20% of cells in each culture expressed HIV proteins or RNA 2 wk after infection. In contrast, levels of HIV-specific RNA and DNA were 3- to 5-fold higher in the retinoic acid-treated over control monocytes 1 wk after infection. That retinoic acid increased levels of HIV gene expression in monocyte cultures without affecting the number of infected cells per culture suggested a transcriptional mechanism for the effect. This was confirmed in the U937 myeloid cell line transfected with HIV LTR linked to a chloramphenicol acetyl transferase reporter gene. Chloramphenicol acetyl transferase activity in lysates of retinoic acid-treated cells were 20-fold higher than that of control cells. These data show that retinoic acid significantly increased HIV replication in monocytes through mechanisms related to cell differentiation and to a direct transcriptional effect on viral gene expression.
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PMID:Enhanced HIV-1 replication in retinoid-treated monocytes. Retinoid effects mediated through mechanisms related to cell differentiation and to a direct transcriptional action on viral gene expression. 156 Feb 8

Poor micronutrient status has been associated, in HIV-positive women, with faster progression of HIV disease and adverse birth outcomes. This randomized, double-blind, placebo-controlled study assessed the effects of vitamin A and multivitamins on birth outcomes in 1075 HIV-positive pregnant women at 12-27 weeks' gestation from Dar es Salaam, Tanzania. There were no differences in baseline plasma vitamin concentrations between groups. 267 women received a placebo, 269 were given vitamin A, 269 were administered a multivitamin excluding vitamin A, and 270 received a multivitamin including vitamin A. There were 30 fetal deaths in the group of women who received multivitamins (with and without vitamin A) compared with 49 among those not given multivitamins (relative risk (RR), 0.61; 95% confidence interval (CI), 0.39-0.94). Multivitamin supplementation decreased the risk of low birth weight (2500 g) by 44% (RR, 0.56; 95% CI, 0.38-0.82), of preterm birth (prior to 34 weeks gestation) by 39% (RR, 0.61; 95% CI, 0.38-0.96), and of small size for gestational age at birth by 43% (RR, 0.57; 95% CI, 0.39-0.82). Vitamin A had no significant effect on these variables. Multivitamins, but not vitamin A, were associated with significant increases in CD4, CD8, and CD3 counts. The clinical relevance of multivitamin supplementation for vertical transmission of HIV and the progression of disease remain unknown. However, these results indicate such supplementation is a low-cost means of substantially decreasing adverse pregnancy outcomes and increasing T cell counts in HIV-infected women. The observed beneficial effects of multivitamins on birth outcomes may have been mediated through improved maternal immune status.
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PMID:Randomised trial of effects of vitamin supplements on pregnancy outcomes and T cell counts in HIV-1-infected women in Tanzania. 974 53

The rates of mother-to-child transmission of human immunodeficiency virus type 1 (HIV-1), progression to AIDS following HIV-1 infection, and AIDS-associated mortality are all inversely correlated with serum vitamin A levels (R. D. Semba, W. T. Caiaffa, N. M. H. Graham, S. Cohn, and D. Vlahov, J. Infect. Dis. 171:1196-1202, 1995; R. D. Semba, N. M. H. Graham, W. T. Caiaffa, J. B. Margolik, L. Clement, and D. Vlahov, Arch. Intern. Med. 153:2149-2154, 1993; R. D. Semba, P. G. Miotti, J. D. Chiphangwi, A. J. Saah, J. K. Canner, G. A. Dallabetta, and D. R. Hoover, Lancet 343:1593-1596, 1994). Here we show that physiological concentrations of vitamin A, as retinol or as its metabolite, all-trans retinoic acid, repressed HIV-1Ba-L replication in monocyte-derived macrophages (MDMs). Repression required retinoid treatment of peripheral monocytes during their in vitro differentiation into MDMs. Retinoids had no repressive effect if they were added after virus infection. Retinol, as well as all-trans retinoic acid and 9-cis retinoic acid, also repressed HIV-1 long terminal repeat (LTR)-directed expression up to 200-fold in transfected THP-1 monocytes. Analysis of HIV-1 LTR deletion mutants demonstrated that retinoids were able to repress activation of HIV-1 expression by both NF-kappaB and Tat. A cis-acting sequence required for retinoid-mediated repression of HIV-1 transcription was localized between nucleotides -51 and +12 of the HIV-1 LTR within the core promoter. Protein-DNA cross-linking experiments identified four proteins specific to retinoid-treated cells that bound to the core promoter. We conclude that retinoids render macrophages resistant to virus replication by modulating the interaction of cellular transcription factors with the viral core promoter.
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PMID:Retinoid-induced repression of human immunodeficiency virus type 1 core promoter activity inhibits virus replication. 962 Oct 47

Vitamin A supplementation has been suggested for treatment and prevention of HIV infection. However, some in vitro data indicate that vitamin A may activate HIV. Randomly, 40 HIV-seropositive women of reproductive age were allocated to receive a single oral dose of 9900 micromol (300,000 IU) vitamin A or placebo. Plasma HIV-1 RNA concentration, total lymphocytes, selected lymphocyte subsets and activation markers, and in vitro lymphocyte proliferation to phytohemagglutinin (PHA) and Candida were measured before dosing and at various time points over an 8-week follow-up period. No differences were found between treatment groups in the frequency of signs or symptoms of acute vitamin A toxicity, nor were differences evident in any lymphocyte subset or activation marker at any time during follow-up. Mean and median viral load concentration at each time point and change in viral load from baseline to each follow-up point did not differ between treatment groups. No difference was measured between treatment groups in the proportion of women who responded to PHA or Candida. This study provides no evidence that high dose vitamin A supplementation of HIV-infected women is associated with significant clinical or immunologic adverse effects.
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PMID:Short-term effects of large-dose vitamin A supplementation on viral load and immune response in HIV-infected women. 992 29

Vitamin A levels in plasma and other nutritional indices were measured during pregnancy for 449 women enrolled in a multicenter cohort study of mother-to-infant transmission of human immunodeficiency virus type 1 (HIV-1). During the third trimester, 29.6% of the women had low (20 to <30 microg/dL) and 11.1% had very low (<20 microg/dL) vitamin A levels. Vitamin A and body mass index, serum albumin levels, and hemoglobin levels were weakly correlated. After adjustment for other covariates, women with low and very low vitamin A levels before the third trimester were more likely to deliver infants with low birth weight (<2500 g) than were those with higher levels (odds ratio [OR], 4.58; 95% confidence interval [CI], 1.57-13.4; and OR, 6.99; 95% CI, 1.09-45.0, respectively). However, there was no statistically significant association between vitamin A level and mother-to-infant transmission of HIV-1. Anemia and low body mass index before the third trimester were associated with an increased risk of transmission in univariate analyses but not in multivariate analyses.
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PMID:Vitamin A deficiency and other nutritional indices during pregnancy in human immunodeficiency virus infection: prevalence, clinical correlates, and outcome. Women and Infants Transmission Study Group. 1047 37

The associations of hemoglobin, hematocrit, and packed cell volume with socioeconomic factors, malaria, human immunodeficiency virus (HIV) infection, and nutritional status were examined among 687 children admitted to hospital with pneumonia participating in a double blind, placebo-controlled trial of vitamin A supplementation. Children were randomized to receive 2 doses of vitamin A (200,000 IU) or placebo at baseline, and additional doses at 4 and 8 months after discharge from hospital. Hemoglobin levels were measured at enrollment and, on a subset of 161 children, during follow-up. At baseline, hemoglobin concentration was positively associated with the number of possessions in the household, maternal level of education and quality of water supply, and inversely related to malaria infection after controlling for potential confounding variables. Children infected with HIV experienced a significant fall in mean hemoglobin levels over time. The risk of developing severe anemia (< 7 g/dL) during follow-up was lower for children who were breastfed for longer than 18 months as compared to those with less than 6 months of breastfeeding (adjusted prevalence ratio = 0.14, 95% confidence interval [CI] = 0.02, 0.93; P = 0.04), and higher for children over two years of age as compared to 6 to 11 months-old infants (adjusted prevalence ratio = 8.11, 95% CI = 1.2, 55.8; P = 0.03). Children with repeated diagnoses of malaria had 4.1 times the risk of developing severe anemia than did children without the diagnosis (95% CI = 1.3, 13.5; P = 0.02). Vitamin A supplements were associated with an overall nonsignificant reduction of 14% in the risk of developing severe anemia (adjusted prevalence ratio = 0.86, 95% CI = 0.37, 1.99; P = 0.73). We conclude that malaria, HIV infection, low socioeconomic status, and short duration of breastfeeding are strong and independent determinants of adverse hematologic profiles in this population.
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PMID:Vitamin A supplementation and other predictors of anemia among children from Dar Es Salaam, Tanzania. 1128 70

Nutritional status directly affects immune competence; therefore, dietary supplements can be beneficial. Vitamin A, a fat-soluble nutrient obtained exogenously from animal protein or synthesized endogenously from carotenoids, is important in vision, epithelial tissue maintenance, reproduction, and growth. It is also an antioxidant, and can interfere with HIV-related oxidative destruction. Vitamin C, a water-soluble antioxidant important in hydroxylation reactions and required by erythrocytes for retrieving stored iron, can suppress HIV in vitro. However, this requires long-term administration, and its effect ceases upon termination of treatment. Vitamin E, fat-soluble tocopherols, can be found in plants, vegetable oils, milk, eggs, fish, meats, and cereals. A potent antioxidant because of its electron-donating ability, vitamin E reduces HIV replication. Deficiency reduces inhibition of tumor necrosis factor alpha (TNF-a) and protein kinase C, therefore limiting immunocompetence. Additionally, damaging side effects of AZT, normally reversed or minimized by vitamin E, may induce low leukocyte counts and anemia. Vitamin E acts synergistically with selenium, another antioxidant, to block the rate of lipid peroxidation. Its administration may reduce diarrhea, cramping, and weight loss, and may improve epithelial conditions and reduce the frequency of illness. N-acetylcysteine (NAC), a sulfur-containing amino acid, inhibits HIV replication by raising serum glutathione levels through inhibition of TNF-a. Finally, HIV-infected patients should consider gluten-free diets during times of acute gastric distress.
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PMID:Nutrition and HIV. 1136 99

The ACTG 076 clinical trial is examining AZT effectiveness at preventing mother to fetus HIV transmission. Preliminary studies embellished the results of this poorly designed and executed study. Initially, scientists were to collect data on 400 children borne of HIV-positive mothers, but data from only 75 were collected and the rest were extrapolated. It is suggested that participation was generated out of fear and coercion. Consent forms exaggerated infection ratios, stating that ninety percent of HIV-positive infants die within their first year. Actually, seventy to eighty percent of infants born to HIV-positive mothers are HIV-negative. Extensive AZT therapy in pregnant women is harmful. Vitamin A therapy has been suggested as a possible alternative for lowering the risks of HIV transmission.
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PMID:[Women yell at the results of 076]. 1136 23

There is renewed interest in antioxidant vitamins A, C, and E as supportive elements in regimens that seek both HIV viral load suppression and immune function restoration with the fewest toxic effects. The electron-deficient free radicals produced in HIV infection have been linked to a long list of tissue damage as well as CD4 cell apoptosis and an inflammatory response through the production of excess tumor necrosis factor. Research has reported that deficiencies in antioxidant nutrients lead to more rapid HIV-associated disease progression; however, correlating antioxidant levels with disease progression is not the same as determining that taking extra vitamins slows HIV progression. Significant amounts of data are mounting that point to potential benefits of antioxidant supplementation, with vitamin E emerging as the most promising. Vitamin A's role as an antioxidant is not completely understood, but its deficiency has been linked to oxidative stress in HIV-positive patients. The body regulates vitamin A levels, so increasing vitamin A is difficult beyond a certain point, and there is no evidence that HIV-influencing levels of vitamin A are achievable, let alone tolerable. Vitamin C research in the lab has shown that very high concentrations help inactivate HIV or kill infected cells, but research on humans is scarce. Studies on the effects of selenium, zinc, thioctic acid, and lecithinized superoxide dismutase on HIV are also being conducted. Results from these studies, like those on vitamins, are generally conflicting and sometimes controversial. How to effectively administer single vitamins as medicine is still not known, and megadose usage is still poorly documented.
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PMID:Antioxidants may still have a role in HIV treatment. 1136 52

With short-course AZT therapies becoming more frequent in developing countries, the impact of antiretroviral therapy for breast-feeding women will become a more critical research area. The only controlled trial of breast-feeding vs. formula feeding is underway in Nairobi; however, at least 24 months will be needed to determine HIV transmission rates from breast-feeding. Other approaches for preventing perinatal transmissions currently being studied include Vitamin A supplementation in Africa, vaginal cleansing, antiviral suppositories, and cesarean section.
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PMID:Studies look at approaches other than antiretovirals. 1136 42


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