1. Endotoxin desensitization of human mononuclear cells after cardiopulmonary bypass: role of humoral factors
U Grundmann, H Rensing, H A Adams, S Falk, O Wendler, N Ebinger, M Bauer Anesthesiology. 2000 Aug;93(2):359-69. doi: 10.1097/00000542-200008000-00013.
Background: The ability of leukocytes to release proinflammatory cytokines on lipopolysaccharide stimulation in vitro is impaired after cardiopulmonary bypass (CPB). This study tested contribution and interaction of humoral factors in altered leukocyte responsiveness to lipopolysaccharide. Methods: Whole blood and isolated peripheral-blood mononuclear cells (PBMCs) from 10 patients obtained after induction of anesthesia (T1) and 20 min (T2) and 24 h (T3) after CPB were cultured in the absence or presence of lipopolysaccharide and assessed for release of tumor necrosis factor alpha (TNF-alpha) and interleukin (IL)-1beta and their functional antagonists, IL-1 receptor antagonist (IL-1ra) and IL-10. In addition, dose-response characteristics and interaction of IL-10 and norepinephrine as modulators of TNF-alpha release were studied. Results: Cardiopulmonary bypass induced release of antiinflammatory (T2: IL-10: median 25 pg/ml, 25th-75th percentile 9-42; IL-1ra: median 1,528 pg/ml, 25th-75th percentile 1,075-17,047; P < 0.05 compared with T1) but failed to induce proinflammatory cytokines (T2: TNF-alpha: median 0 pg/ml, 25th-75th percentile 0-6; IL-1beta: median 1 pg/ml, 25th-75th percentile 0-81; nonsignificant). Removal of plasma at T2 increased TNF-alpha response to lipopolysaccharide (+83.8%; P < 0.05), whereas it suppressed IL-10 (-36.8%; P < 0.05). Similarly, incubation of PBMCs (T1) with plasma obtained after CPB (T2) as well as addition of IL-10 or norepinephrine in concentrations present in plasma after CPB led to a reduced lipopolysaccharide-stimulated TNF-alpha and an increased IL-10 response. Coadministration of norepinephrine and IL-10 had synergistic effects. Although pretreatment with an anti-IL-10 antibody and labetalol before addition of plasma obtained at T2 largely restored the TNF-alpha response in vitro, their addition post-treatment failed to restore the monocytic TNF-alpha response. Conclusions: Plasma contains interacting factors that inhibit the release of TNF-alpha and increase the release of IL-10, presumably attenuating the inflammatory response to CPB. Although norepinephrine fails to induce a cytokine response in the absence of other stimuli, its administration seems to augment the antiinflammatory IL-10 response while attenuating the TNF-alpha response.
2. The effect of losartan and amlodipine on serum adiponectin in Japanese adults with essential hypertension
Sanae Watanabe, Takafumi Okura, Mie Kurata, Jun Irita, Seiko Manabe, Ken-ichi Miyoshi, Tomikazu Fukuoka, Kazuo Murakami, Jitsuo Higaki Clin Ther. 2006 Oct;28(10):1677-85. doi: 10.1016/j.clinthera.2006.10.012.
Background: Adiponectin, an adipocyte-derived protein, is reduced in patients with hypertension and insulin resistance (IR). Angiotensin II receptor blockers (ARBs) have been reported to improve IR and reduce albuminuria. The purpose of this study was to evaluate the influence of an ARB and a calcium channel blocker on serum adiponectin levels in Japanese patients with hypertension who were treated with losartan or amlodipine for 3 months. Methods: Patients with essential hypertension (EHT) were randomized to treatment prospectively with losartan (50-100 mg/d) or amlodipine (5-10 mg/d) for 3 months. Patients with renal damage and/or macroproteinuria were excluded. The urine albumin/creatinine ratio, homeostasis model assessment (HOMA) index, adiponectin concentration, and tumor necrosis factor-alpha (TNF-alpha) concentration of each patient were evaluated before and after 3 months of treatment. When the HOMA index exceeded 1.73, a patient was considered to have IR. Results: All 40 participants completed both 3-month treatment periods. Study patients were primarily male (52.5%) with a mean (SD) age of 63.8 (10.6) years and a mean body weight of 60.7 (10.8) kg. Patients with EHT and diabetes mellitus (n = 9) and IR (n = 12) had significantly lower adiponectin concentrations than patients who had EHT without diabetes or IR (n = 19; mean [SD], 7.84 [5.54] vs 12.81 [7.36] microg/mL, P = 0.034; and 6.12 [3.04] vs 12.81 [7.36] microg/mL, P = 0.004, respectively). Adiponectin concentrations correlated negatively with body mass index (r = -0.393; P = 0.012) and HOMA index (r = -0.440; P = 0.005) and positively with high-density lipoprotein cholesterol (r = 0.441; P = 0.004) before treatment. Systolic blood pressure was significantly decreased in patients treated with losartan (n = 20; mean [SD], 166 [19] to 140 [15] mm Hg; P < 0.001) or amlodipine (n = 20; 164 [15] to 136 [15] mmHg; P < 0.001), and diastolic blood pressure also was significantly decreased with losartan (93 [14] to 83 [10] mm Hg; P = 0.031) or amlodipine (96 [12] to 82 [10] mm Hg; P < 0.001). Losartan increased adiponectin concentrations (9.56 [6.75] to 10.36 [6.94] microg/mL; P = 0.038), whereas amlodipine had no significant effect (9.67 [6.62] to 10.01 [6.79] microg/mL). The difference in TNF-alpha concentration before and after treatment with losartan and amlodipine did not reach statistical significance (mean [SD], 15.2 [1.4] to 14.8 [1.5] pg/mL; and 14.3 [1.4] to 14.5 [1.7] pg/mL, respectively). Conclusion: In this study, Japanese adults with EHT had significant increases in adiponectin after 3 months of treatment with 50 to 100 mg/d of losartan, but not with 5 to 10 mg/d of amlodipine.
3. Impact of alloantigens and storage-associated factors on stimulated cytokine response in an in vitro model of blood transfusion
Andreas E Biedler, Sven O Schneider, Ullrich Seyfert, Hauke Rensing, Sasha Grenner, Matthias Girndt, Inge Bauer, Michael Bauer Anesthesiology. 2002 Nov;97(5):1102-9. doi: 10.1097/00000542-200211000-00011.
Background: Transfusion of blood may contribute to immunosuppression in major surgery. The authors assessed the impact of alloantigens and storage on function of peripheral blood mononuclear cells cultured in their physiologic environment. Methods: Blood units (whole blood, packed erythrocytes) were prepared with or without prestorage leukodepletion and stored for 24-26 days. Blood samples were coincubated with allogeneic fresh blood, autologous, or allogeneic stored blood. Endotoxin-stimulated release of tumor necrosis factor-alpha (TNF-alpha) and interleukin 10 (IL-10) was measured after 24 h of culture by enzyme-linked immunosorbent assay. Results: Coincubation with equal amounts of allogeneic fresh blood showed almost no influence on TNF-alpha (-12%, not significant) and IL-10 (+11%, not significant) release. Stored allogeneic whole blood resulted in a significant TNF-alpha depression (-61%) and IL-10 induction (+221%). These effects were diminished but not prevented by prestorage leukodepletion (TNF-alpha -42%, IL-10 +110%) and required the presence of soluble factors (TNF-alpha suppression) and cellular components (IL-10 induction). TNF-alpha decrease and IL-10 increase were in the same order of magnitude (-40%, +134% with, -65%, +314% without leukodepletion) after coincubation with autologous blood. In contrast, allogeneic erythrocytes had only little effects (TNF-alpha -6%, IL-10 +36%) even at this high transfusion equivalent. Conclusion: These data suggest that banked whole blood has an immunosuppressive effect that is largely attributable to storage-dependent factors. These factors are partially removed by prestorage leukodepletion, while the contribution of alloantigens is of minor significance. Immunosuppressive effects are least apparent with leukodepleted erythrocytes, suggesting that the presence of plasma during storage is required for the immunosuppressive effect to develop.
