Background: Dietary fish oil, rich in omega-3 polyunsaturated fatty acids, decreases TNF-alpha, IL-1beta and IL-2 levels, which may benefit renal transplant recipients. To explore this possibility, we studied the effect of fish oil on the incidence of acute rejection, in situ expression of interleukins (TNF-alpha, IL-1beta and IL-2) and renal function after renal transplantation.
Methods: In a double-blind clinical trial, 86 subjects with no immunological risk randomly received either 6 g/day of fish oil (fish oil group; n=46) or soy oil (control group; n=40) during the first 3 months after transplantation. The mRNA expression of interleukins (TNF-alpha, IL-1beta and IL-2) was determined by RT-PCR using fine-needle aspiration during follow-up (at baseline and the 1st, 2nd and 3rd month after renal transplantation), as well as during acute rejection episodes and after anti-rejection therapy. The glomerular filtration rate was determined at baseline, and at 1 and 3 months post-graft by [(51)Cr]EDTA clearances.
Results: The incidence of acute rejection during the first post-transplant year was similar in both groups (44 vs. 47%), as was 1-year graft survival (86 vs. 89%). There were no differences between groups in overall renal expression of interleukins in patients who did not suffer rejections during the study. At rejection episodes, the fish oil group showed a trend toward a lower renal expression of TNF-alpha (3.7+/-6.8 vs. 15+/-18.6 TNF-alpha/actin, ratio of arbitrary optical units; P=0.05). In addition, a trend toward a lower IL-1beta expression after therapy was observed in the fish oil group (49.3+/-54 vs. 84.4+/-59 IL-1beta/actin, ratio of arbitrary optical units; P=0.05). However, the severity of acute rejections (Banff criteria) as well as renal function after anti-rejection treatment were similar in both groups. Finally, a greater reduction in triglyceride levels was observed in the fish oil group compared with the control group (-6.6+/-52.7 vs. 12.7+/-40.2%; P<0.05).
Conclusions: Treatment with fish oil during the first 3 months post-transplantation does not influence acute rejection rate and has no beneficial effect on renal function or graft survival.