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Effect of cardiopulmonary bypass on the circulating level of soluble GMP-140
1Vascular Biology and Pharmacology Unit, Institute of Child Health, London, England.
Insights
Soluble GMP-140, released from activated platelets during heart surgery, was higher in children with low pulmonary blood flow. This suggests a potential protective role against neutrophil-endothelial interactions in these patients.
Area of Science:
- Cardiovascular Surgery
- Hematology
- Pediatric Cardiology
Background:
- Cardiopulmonary bypass (CPB) can induce neutrophil-endothelial interactions.
- Soluble GMP-140 (sGMP-140) is known to inhibit neutrophil adhesion to endothelium in vitro.
- Activated platelets are a significant source of GMP-140 release.
Purpose of the Study:
- To measure plasma levels of sGMP-140 and beta-thromboglobulin (a marker of platelet activation) in children undergoing congenital heart disease repair.
- To investigate the relationship between these markers and pulmonary blood flow status during CPB.
- To explore the role of sGMP-140 as a protective factor against CPB-induced endothelial injury.
Main Methods:
- Enzyme immunoassay was used to measure plasma sGMP-140 and beta-thromboglobulin levels.
- Blood samples were collected from 32 children before, during, and up to 24 hours after CPB.
- Patients were categorized based on preoperative pulmonary blood flow: high, low, or normal.
Main Results:
- Plasma sGMP-140 and beta-thromboglobulin levels increased post-CPB in all patients.
- The increase in both markers was significantly greater in children with low pulmonary blood flow (p < 0.05).
- sGMP-140 levels correlated negatively with preoperative mean pulmonary arterial pressure and positively with beta-thromboglobulin levels.
Conclusions:
- CPB activates platelets, leading to increased sGMP-140 release, particularly in children with low pulmonary blood flow.
- Elevated sGMP-140 in low pulmonary blood flow patients may indicate a compensatory protective mechanism.
- Patients with high pulmonary blood flow might be less protected by sGMP-140 and potentially more susceptible to endothelial injury.
Abstract:
Soluble GMP-140 can prevent the adhesion of activated neutrophils to endothelium in vitro. Because cardiopulmonary bypass causes neutrophil-endothelial interaction, the plasma level of soluble GMP-140 was measured using an enzyme immunoassay system in 32 children undergoing intracardiac repair of congenital heart disease. They had either a high, low, or normal pulmonary blood flow (n = 13, 12, and 7 respectively). Because activated platelets are a source of GMP-140, the plasma beta-thromboglobulin level was also measured. Blood was sampled before, during, and for 24 hours after cardiopulmonary bypass. Plasma levels of both soluble GMP-140 and beta-thromboglobulin increased after the onset of cardiopulmonary bypass in all patients but for both substances the increase was greater in those with a low pulmonary blood flow (p < 0.05 for all comparisons). The sum total of soluble GMP-140 values during and after operation was correlated negatively with the preoperative mean pulmonary arterial pressure (p < 0.05 for all time intervals). GMP-140 level correlated with the plasma beta-thromboglobulin level (r = 0.5, p < 0.05). This work supports the contention that soluble GMP-140 is released from activated platelets during cardiopulmonary bypass, the level being particularly high in those who had intrinsically abnormal platelets preoperatively in association with a low pulmonary blood flow. Patients with a high pulmonary blood flow, who are more susceptible to endothelial cell injury, may be less well protected by soluble GMP-140.