Myocardial and lung injury after cardiopulmonary bypass: role of interleukin (IL)-10

Abstract

Background: Proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-6, and IL-8 play a key role in the inflammatory cascade after cardiopulmonary bypass (CPB) and may induce cardiac and lung dysfunction. Antiinflammatory cytokines such as IL-10 may also significantly limit these complications. Corticosteroid administration before CPB increases blood IL-10 levels and prevents proinflammatory cytokine release. This study examined the association of increased release of IL-10, stimulated by steroid pretreatment, with reduced myocardial and lung injury after CPB.

Methods: Twenty patients undergoing coronary artery bypass grafting (CABG) received either preoperative steroid (n = 10, protocol group) or no steroid (n = 10, control group). Perioperative care was standardized, and all caregivers were blinded to treatment group. Seven intervals of blood samples were obtained and assayed for TNF-alpha, IL-6, IL-8, and IL-10. Various hemodynamic and pulmonary measurements were obtained perioperatively. Levels of MB isoenzyme creatine kinase (CK-MB) were also measured.

Results: In the protocol group, proinflammatory cytokines were significantly reduced while IL-10 levels were much higher after CPB. The protocol group had a lower alveolar-arterial oxygen gradient and higher ratio of arterial oxygen pressure to fraction of inspired oxygen after CPB. Creatine kinase (CK) and CK-MB were reduced in the patients treated with steroid. Correlations were found between plasma cytokines levels and cardiac index, and CK-MB.

Conclusions: This study confirms that corticosteroids abolish proinflammatory cytokines release and increase blood IL-10 levels after CPB. Our findings demonstrate a greater release of IL-10 induced by steroid pretreatment, and better heart and lung protection after CPB.