The Study of the Effects of Vitamin A on Immune System in Patients With Atherosclerosis

Tehran University of Medical Sciences

Status and phase: Unknown; Phase 4

Conditions: Atherosclerosis

Treatments: Drug: placebo; Drug: vitamin A

Study type: Interventional

Funder types: Other

Identifiers

NCT00963222

86-04-27-6617

Details and patient eligibility

About

The aim of this study is the comparison between the effects of supplementation with 25000 IU preformed vitamin A (retinyl palmitate) or placebo for 3 months on immune system and Th1/Th2 balance in patients with and without atherosclerosis (documented with angiography).

Full description

Atherosclerosis, the leading cause of death and disability in the world, is considered an inflammatory disease with a complex etiology. The immune system has a prominent role in the formation, development and destabilization of atherosclerotic plaques. A whole range of identified cytokines have been shown to play a part in atherogenesis, some with proatherogenic properties while others having antiatherogenic properties. With increasing evidence for the significant role of inflammation and the cytokines involved together with the Th1/Th2 imbalance in atherosclerosis and its progression to Coronary artery diseases (CADs), the control of cytokine production may become potential therapeutic targets and modulation of the Th1/Th2 balance may provide a new pharmacological tool to treat this disease. Vitamin A (VA) or VA-like analogs known as retinoids, are potent hormonal modifiers of type 1 or type 2 responses but a definitive description of their mechanism(s) of action is lacking. high level dietary vitamin A enhances Th2 cytokine production and IgA responses, and is likely to decrease Th1 cytokine production. Retinoic acid inhibits IL 12 production in activated macrophages, and RA pretreatment of macrophages reduces IFNγ production and increases IL4 production in antigen primed CD4 T cells. Supplemental treatment with vitamin A or retinoic acid (RA) decreases IFNγ and increases IL5, IL10, and IL4 production. Thus, vitamin A deficiency biases the immune response in a Th1 direction, whereas high level dietary vitamin A may bias the response in a Th2 direction.

Enrollment: 60 estimated patients

Sex: All

Ages: 35 to 60 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• The criteria for enrollment of the patients and control subjects is consecutive patients of both sexes referred to the Division of Cardiology of the one of the Hospitals of Tehran University of Medical Sciences for coronary angiography for investigation of chest pain and/or suspected CAD.

Exclusion criteria

• Patients who have diseases which affect on Th1/Th2 balance such as asthma, active viral infections, and autoimmune diseases, OR
• Patients who have allergy to vitamin A compounds, OR
• Patients who have used vitamin supplements in last 3 months.

Trial design

Primary purpose: Prevention

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Quadruple Blind

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60 participants in 4 patient groups, including a placebo group

with atherosclerosis/ vitamin A

Active Comparator group

Description:

patients with angiographically confirmed CAD (defined as luminal stenosis ≥50% in at least one major coronary artery branch)who receive 25000 IU/day vitamin A

Treatment:

Drug: vitamin A

with atherosclerosis/ placebo

Placebo Comparator group

Description:

patients with angiographically confirmed CAD (defined as luminal stenosis ≥50% in at least one major coronary artery branch)who receive placebo

Treatment:

Drug: placebo

without atherosclerosis/ vitamin A

Active Comparator group

Description:

patients in whom significant (e.g. stenosis ≥ 50%) CAD is ruled out by coronary angiography, who receive 2500 Iu/day vitamin A

Treatment:

Drug: vitamin A

without athrosclerosis/ placebo

Placebo Comparator group

Description:

patients in whom significant (e.g. stenosis ≥ 50%) CAD is ruled out by coronary angiography, who receive placebo

Treatment:

Drug: placebo