Published in:
01-09-2010 | Original Research Paper
Inadequate cytoplasmatic calcium signals in alveolar macrophages after cardiac surgery
Published in: Inflammation Research | Issue 9/2010
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Objective and design
Patients undergoing cardiac surgery have an elevated risk for pulmonary complications. A dysfunction of alveolar macrophages (AM) might promote postoperative infections. Therefore intracellular calcium [Ca2+]i as an important second messenger in cellular signaling was assessed in AM.
Materials and methods
Twelve patients undergoing elective coronary artery bypass graft surgery (CABG) were enrolled in this clinical trial. After anesthesia induction and 2 h after cardiopulomary bypass (CPB) declamping, the bronchoalveolar lavage (BAL) fluid was collected preoperatively from the right middle lobe and postoperatively from the left lingula of the lung. Cell subpopulations and [Ca2+]i signals were assessed via flow cytometry. To express the changes of [Ca2+]i signals the Fluo4/FuraRed-Ratio was used.
Results
After surgery the [Ca2+]i baseline in unstimulated AMs were significantly reduced (p < 0.001). A significant signal reduction after fMLP (p = 0.021) and C5a (p = 0.028) stimulation was found in FSC high AMs after surgery, even though all populations showed a trend of less responsiveness.
Conclusion
We suggest that the reduced [Ca2+]i signaling in postoperative AMs is caused by a reduced coupling to membrane channels. These preliminary data suggest an inadequate [Ca2+]i signal of AM after surgery, which may contribute to a local immune dysfunction in the lung.