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Glucocorticoids alter the balance between pro- and anti-inflammatory mediators in the myocardium in a porcine model of brain death.

Research paper by Kelly M KM McLean, Jodie Y JY Duffy, Prakash K PK Pandalai, Jefferson M JM Lyons, Christian F CF Bulcao, Connie J CJ Wagner, Shahab A SA Akhter, Jeffrey M JM Pearl

Indexed on: 20 Jan '07Published on: 20 Jan '07Published in: The Journal of Heart and Lung Transplantation



Abstract

Cardiac dysfunction after brain death (BD) limits donors for cardiac transplantation. Glucocorticoids ameliorate brain death-induced donor heart dysfunction. We hypothesized that glucocorticoid therapy alleviates myocardial depression through altering the balance between pro- and anti-inflammatory mediators via the nuclear factor-kappaB (NF-kappaB)/inhibitor of kappaB-alpha (IkappaBalpha) pathway and/or by preserving beta-adrenergic receptor (betaAR) signaling in the heart.Crossbred pigs (25 to 35 kg) were randomly assigned to the following groups (n = 5/treatment): sham (Group 1); BD (Group 2); and BD with glucocorticoids (30 mg/kg methylprednisolone), either 2 hours before (Group 3) or 1 hour after BD (Group 4). Tumor necrosis factor-alpha (TNF-alpha) levels were measured in plasma at baseline and 1 hour and 6 hours after BD. Protein levels were measured in left ventricular homogenates procured 6 hours after BD.Pro-inflammatory proteins (TNF-alpha) and interleukin-6 were lower in Group 3 and Group 4 compared with Group 2 at 6 hours after BD (p < 0.01). Intracellular adhesion molecule-1 was also lower in Group 4 compared with Group 2 (p = 0.001). Interleukin-10, an anti-inflammatory mediator, was lower in Group 4 than in Group 2 (p < 0.001), but not different between Groups 2 and 3. At 6 hours after BD, neither NF-kappaB activity nor basal adenylate cyclase activity differed between Groups 3 and 4 compared with Group 2.Glucocorticoids maintained myocardial function and shifted the balance of pro- and anti-inflammatory mediators after BD. The mechanisms by which glucocorticoids preserve myocardial function, however, do not appear to involve the NF-kappaB pathway or betaAR signaling.