Kazuo Nakamura

We conducted a pilot study in patients undergoing cardiac surgery to investigate the influence of a dietary supplement enriched in omega-3 fatty acids on immune responses. Patients in the supplement group (n = 7) received a dietary supplement enriched in ω-3 fatty acids, namely Impact® for 5 successive days before surgery; those in the control group (n = 7) did not receive Impact®. Blood samples in both groups were collected at same time points. Before surgery, samples were collected on 5 days before surgery at the start of supplementation (baseline) and the end of supplementation (postoperative day (POD)-0). After surgery, samples were collected on POD-1 and POD-7. The expression of human leukocyte antigen (HLA)-DR, the ratio of CD4-/CD8-positive cells, the production of IFN-γ by CD4-positive cells, plasma levels of cytokines, and leukocyte-platelet aggregates were measured. Before surgery (POD-0), the supplement caused significant increases in HLA-DR expression, CD4/CD8 ratio, and plasma levels of IFN-; these levels were significantly higher compared to those in the control group (p < 0.01, respectively). After surgery (POD-1), all values dramatically decreased in comparison with those of POD-0; however, the values in the supplement group were significantly higher compared to their respective markers in the control group (p < 0.05, respectively). Significant differences of HLA-DR expression and CD4/CD8 ratio persisted through POD-7. Before surgery (POD-0), plasma levels of IL-10 in the supplement group decreased significantly compared with those in the control group (p < 0.05). After surgery (POD-1), plasma levels of IL-10 in both the control and supplement groups increased; these levels in the supplement group were significantly lower than those in the control group (p < 0.01). Significant decreases in the percentage of leukocyte-platelet aggregates were found after supplementation; the difference between the supplement and the control groups was found on POD-0 and POD-1 (P < 0.01, respectively). In conclusion, the dietary supplement increased HLA-DR expression, the CD4/CD8 ratio, and the production of IFN-γ by CD4-positive cells; conversely, the levels of IL-10 and the formation of leukocyte-platelet aggregates before and after surgery were suppressed. These beneficial effects may decrease the incidence of complications after surgery.