Vitamin A Decreases Cytotoxicity of Oxidized Low-Density Lipoprotein in Patients with Atherosclerosis.

BACKGROUND: Oxidized low-density lipoprotein (ox-LDL) is implicated in initiation and progression of atherosclerosis. Previously, we found that ox-LDL increases vulnerability of peripheral blood mononuclear cells (PBMCs) in atherosclerotic patients compared to controls. Vitamin A induces proliferation of PBMCs. The aim of this study was to determine the effect of vitamin A supplementation on PBMC survival against LDL and different doses of ox-LDL. METHOD: In this double-blind placebo-controlled trial, we recruited 35 atherosclerotic patients and 38 healthy controls and randomly allocated them into placebo and vitamin A groups, which received either placebo or 25,000 IU/day of vitamin A for 3 months. PBMCs were isolated, cultured, and stimulated by 1 µg/mL LDL as well as 1 µg/mL and 50 µg/mL ox-LDL. The stimulation indexes (SIs) of PBMCs were calculated to identify cell viability. Additionally, the circulating ox-LDL levels were measured by ELISA. RESULTS: Viability of PBMCs stimulated by 50 µg/mL ox-LDL significantly increased following vitamin A supplementation in patients (p < 0.01). The levels of circulating ox-LDL were not changed by vitamin A treatment. Ox-LDL levels were strongly and positively correlated to SI of PBMCs stimulated by 1 µg/mL LDL and1 µg/mL ox-LDL in all groups. CONCLUSION: Vitamin A decreases cytotoxicity of high-dose ox-LDL and improves PBMC viability. The protective effect of vitamin A is not mediated by an antioxidative mechanism, but may instead have been due to intracellular protection of the apoptotic machinery or induction of proliferation of the cells. Higher levels of ox-LDL increase PBMC irritability in all participants.

The effect of vitamin A supplementation on disease progression, cytokine levels and gene expression in multiple sclerotic patients: study protocol for a randomized controlled trial.

Multiple Sclerosis (MS) is a chronic inflammatory disease that leads to degeneration of the brain and spinal tissue. Imbalances of CD4+ T cells including Thelper1 (Th1)/Thelper2 (Th2) and Thelper17 (Th17)/Tregulatory (Treg), their secreted cytokines and gene expressions, are important aspects of in immunopathogenesis of MS. Vitamin A and its metabolites can regulate the immune system and appears to be effective in preventing progression of the autoimmune disease such as MS. Disease progression was evaluated By Magnetic Resonance Imaging (MRI), Expanded Disability States Scale (EDSS) and Multiple Sclerosis Functional Composite (MSFC) tests. Cytokine levels were measured using ELISA kits and gene expression was quantified by Real time PCR (RT-PCR) system. According to the difference between the epidemiological and clinical data on the relationship between vitamin A and immune system regulation, this study of the first time assesses Immune function as well as gene expression and progression of the disease following administration of vitamin A supplement.

The effect of vitamin a supplementation on biochemical parameters in multiple sclerosis patients.

BACKGROUND: Vitamin A has different functions in the body and after being converted to acid form; it can play many roles in immune system regulation. Therefore, this vitamin can be used as a supplement in the treatment of diseases, such as cancer and autoimmune diseases. Vitamin A is a fat-soluble compound and its long-term consumption in high doses can have some adverse effects. OBJECTIVE: The current study aimed to investigate the possible complications and find solutions to minimize the adverse effects. PATIENTS AND METHODS: This study was a double blind randomized clinical trial. In the main study, vitamin A (as retinyl palmitate) was given to 35 multiple sclerosis (MS) patients in order to regulate their immune system with a dose of 25000 IU/day for a period of six months. To investigate the possible biochemical complications, lipid profiles, fasting blood sugar (FBS), liver enzymes, and C-reactive protein (CRP) were tested. RESULTS: Vitamin A did not have a significant difference in lipid profiles, FBS and liver enzymes between the two groups receiving vitamin A and the placebo, but CRP increased in patients who were taking vitamin A, 1.65±0.43 (mg/L) and 2.88±0.67, (Mean±SEM), before and after the intervention respectively (P=0.029), and statistical analysis showed significant differences with the group receiving placebo (P=0.011) and CRP level in vitamin A group was 1.3 mg/L more than those of the placebo group after intervention (P=0.011). CONCLUSIONS: Considering that no significant difference was found in the proven vitamin A side effects, due to the increase in CRP, frequent clinical and biochemical controls are required along with vitamin A supplementation.

The effect of vitamin A supplementation on stimulated T-cell proliferation with myelin oligodendrocyte glycoprotein in patients with multiple sclerosis.

BACKGROUND: Multiple sclerosis (MS) is an autoimmune disease whereby myelin sheath of the central nervous system is destroyed. Vitamin A is known to play a role in the immune system. It has been recognized that some metabolites of vitamin A can be used effectively to treat experimental autoimmune encephalomyelitis (EAE). AIMS: The effect of vitamin A as retinyl palmitate on T-cell proliferation in MS patients. SETTING AND DESIGN: This study is a double blind clinical trial of two test groups over a period of 6 months. MATERIALS AND METHODS: Thirty five multiple sclerosis (MS) patients were divided into two groups. One group received 25,000 IU/day vitamin A (as retinyl palmitate) and the other group were administered a placebo. The peripheral blood mononuclear cells (PBMCs) were separated and stimulated with myelin oligodendrocyte glycoprotein (MOG) and phytohemagglutinin (PHA) before and after the trial period. BrdU calorimetric assay was performed to measure cell proliferation. STATISTICAL ANALYSIS: Analysis of covariance (ANCOVA) and paired t-test were used to analyze the data. RESULTS: Observations showed statistical significant differences in the reduction of cell proliferation in the presence of MOG and fetal calf serum (FCS) in the culture medium, between patients receiving vitamin A and the placebo (P = 0.046). Although, this difference was not significant between the two vitamin A and placebo groups in MOG treatment with human serum, a decrease was observed in the group of patients taking vitamin A supplements (P = 0.019). Phytohemagglutinin did not cause any change in cell proliferation between the two groups. CONCLUSION: The results suggest supplementation with retinyl palmitate in patients with MS reduce MOG stimulatory effects on T-cells.

Relation between nitrate and nitrite food habits with lung cancer.

Nitrites, a probable human carcinogen, generate reactive nitrogen species that may cause damage to the lung. We evaluated the association between nutritional habits related to nitrite and nitrate intake and risk of lung cancer in Mazandaran, Northern Province of Iran. In this case-control study the two groups were matched for gender and age (+/- 5 years). A semi -quantitative food frequency questionnaire (FFQ) was used to collect dietary data about nutritional habits related to nitrate, nitrite, vitamins E and C intake, from 40 lung cancer cases and 40 control subjects admitted at Mazanaran hospitals. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) for the risk of lung cancer using logistic regression. Mean score of nutritional habits in case group was significantly lower than that in control group (P less than or equal 0.001). We observed a positive association between animal sources of nitrate and nitrite intake (OR = 2.7, 95% CI: 0.13-0.96) and risk of lung cancer. Decreased risk of lung cancer was also observed with fruit intake (OR = 0.26, 95% CI: 1.3-11). Our results indicate a probable association between nutritional habits related to animal sources of nitrate and nitrite intake and the risk of lung cancer that requires to be confirmed by other studies.