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Vitamin C And E Slow Arteriosclerosis After Heart Transplant

Supplementation with vitamin C and E appears to have clinical benefit in delaying then onset of arteriosclerosis in patients during the first year after heart transplantation.

Dr James Fang and colleagues at the Cardiovascular Division, Brigham and Women's Hospital, Boston, Massachusetts, United States, add that "antioxidant therapy with these vitamins may also be useful in other solid-organ allografts, such as kidney, lung, and liver transplants, in which obliteration of vascular or tubular structures limits long-term success."

The researchers carried out a double-blind prospective study based on a premise that treatment with antioxidant vitamins C and E would retard the progression of transplant-associated arteriosclerosis. They point out that transplant-associated arteriosclerosis is now the most important factor in long-term survival of cardiac-transplant recipients. Intravascular ultrasonography (IVUS) shows it is present in more than 70 percent of recipients three years after receiving a transplant.

Cardiac transplantation is associated with oxidant stress. Although the role of oxidant stress is supported by animal models, where antioxidants prolong survival after cardiac transplantation, antioxidants have not been investigated for the prevention of this disease in human cardiac transplantation.

Forty patients, between 0-2 years after heart transplantation, were randomly assigned vitamin C 500 mg plus vitamin E 400 IU, each twice daily, or placebo, for one year. The primary endpoint was the change in average intimal index measured by intravascular ultrasonography (IVUS).

Coronary endothelium-dependent vasoreactivity was assessed with intracoronary acetylcholine infusions. IVUS, coronary vasoreactivity, and vitamin C and E plasma concentrations were assessed at baseline and at one year follow-up.

As expected, that Vitamin C and E concentrations increased in the treatment group, but not in the placebo group. During one year of treatment, the intimal index increased in the placebo group by 8 percent but did not change significantly in the treatment group. Coronary endothelial function remained stable in both groups.

The results in transplant-associated arteriosclerosis differ from those of trials in native coronary atherosclerosis, in which vitamin E used alone did not improve outcome. "This apparent discrepancy might be explained by a greater role for the immune system in the pathogenesis of transplant-associated arteriosclerosis as well as by potentially pro-oxidant actions of vitamin E used alone?Vitamin C can act as a 'coantioxidant' with vitamin E by regenerating tocopherol from the tocopheroxyl radical, which otherwise may initiate lipid peroxidation. For this reason, the combination of vitamins C and E may have been better than vitamin E alone."

The clinicians conclude that further trials are needed to investigate "whether the beneficial effects of vitamins C and E are sustained over many years when most of the clinical complications resulting from transplant-associated arteriosclerosis occur."
Lancet 2002; 359: 1108?13

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