Cell activation state influences the modulation of HLA-DR surface expression on human monocytes/macrophages by parenteral fish oil lipid emulsion

摘要

Abnormal surface expression of HLA-DR by leukocytes is associated with a poor prognosis in critical care patients. Critical care patients often receive total parenteral nutrition with lipid emulsion (LE). In this study we evaluated the influence of fish oil LE (FO) on human monocyte/macrophage (M phi) expression of surface HLA-DR under distinct activation states. Mononuclear leukocytes from the peripheral blood of healthy volunteers (n=18) were cultured for 24 hours without LE (control) or with 3 different concentrations (0.1, 0.25, and 0.5) of the follow LE: a) pure FO b) FO in association (1:1-v/v) with LE composed of 50 medium-chain trygliceride and 50 soybean oil (MCTSO), and c) pure MCTSO. The leukocytes were also submitted to different cell activation states, as determinate by INF-g addition time: no INF-gamma addition, 18 hours before, or at the time of LE addition. HLA-DR expression on MO surface was evaluated by flow cytometry using specific monoclonal antibodies. In relation to controls (for 0.1, 0.25, and 05: 100) FO decreased the expression of HLA-DR when added alone in simultaneously-activated M., for 0.1: 70 (59 +/- 73); for 0.25: 51 (48 +/- 56); and for 05: 52.5 (50 +/- 58)1 or in association with MCTSO in simultaneously-activated MO, for 0.1: 50.5 (47 +/- 61); for 25: 49 (45 +/- 52); and for 0.5: 51 (44 54) and in previously-activated Mf, for 1.0: 63 (44 +/- 88); for 0.25: 70 (41 +/- 88); and for 0.5: 59.5 (39 +/- 79)1 in culture medium (Friedman p < 0.05). In relation to controls (for 0.1, 0.25, and 0.5: 100), FO did not influence the expression of these molecules on non-activated M phi for 0.1: 87.5(75 +/- 93); for 0.25: 111 (98 +/- 118); and for 0.5: 101.5 (84 +/- 113). Results show that parenteral FO modulates the expression of HLA-DR on human MO surface accordingly to leukocyte activation state. Further clinical studies evaluating the ideal moment of fish oil LE infusion to modulate leukocyte functions may contribute to a better understanding of its immune modulatory properties.