Cod-liver oil, rich in
eicosapentaenoic acid, an
unsaturated fatty acid, was administered to 14 mongrel dogs to determine if this
acid would prevent platelet-mediated intimal
hyperplasia. Twenty-eight 1 cm segments of undistended jugular vein were interposed between bilaterally divided femoral arteries. Seven control animals were fed a 2%
cholesterol diet 1 week before and for 6 weeks after the operation. A further seven animals received
cod-liver oil capsules containing 1.8 gm of
eicosapentaenoic acid daily 1 week before and for 6 weeks after autogenous vein implantation, in addition to the
lipid-supplemented diet. Baseline serum
cholesterol was 4.6 +/- 0.4 mmol/L. The rise in serum
cholesterol was similar in the two groups and increased to 7.4 +/- 0.6 mmol/L (control group) and to 6.8 +/- 0.2 mmol/L (
eicosapentaenoic acid group) (p less than 0.001). Prothrombin time, partial thromboplastin time, bleeding time, and platelet counts were unchanged in the two groups. Vein grafts, harvested at 6 weeks, were fixed in
formaldehyde. Mean intimal thickness was measured from multiple vein graft cross sections with a Zeiss computerized interactive image analyzing system. A mean of 140 +/- 11 measurements were computed from each graft. Marked intimal
hyperplasia occurred in the control group and increased from 4.3 +/- 0.3 to 86.4 +/- 14 micron. In contrast, a high
eicosapentaenoic acid diet inhibited intimal
hyperplasia, with intimal thickness only increasing from 4.0 +/- 0.4 to 24.8 +/- 2.7 micron (p less than 0.001). These data indicate that
eicosapentaenoic acid inhibits platelet-mediated intimal
hyperplasia and suggest that
cod-liver oil could be used to prevent intimal
hyperplasia in vein grafts used for
myocardial revascularization.