Prostaglandins (PGs) and thromboxane (TX) are important mediators of inflammation. Recent studies revealed that PG and TX synthesis is controlled by the regulation of PG- and TX-synthesizing enzymes. In this study, we examined the TX synthesis and the expression of TX-synthesizing enzymes in activated peripheral polymorphonuclear leukocytes (PMNs) obtained from children with bacterial infection. Blood samples were obtained from controls and patients with bacterial infection. A23187-stimulated production of TXB(2), a stable metabolite of TXA(2) in PMNs, was measured by a specific radioimmunoassay. The mRNA expression of cytosolic phospholipase A(2) (cPLA(2)), cyclooxygenase (COX)-1, COX-2, and TXA(2) synthase was determined by RT-PCR. The synthesis of TXB(2) in PMNs was significantly increased in the patients [925.0 (550.0-1100.0) pg/10(6) cells], compared with the controls [550.0 (450.0-775.0) pg/10(6) cells]. The mRNA expression for cPLA(2) and COX-2 in PMNs was also enhanced in the patients. The results indicate that TX production in PMNs is significantly increased through possible transcriptional mechanisms of cPLA(2) and COX-2 during bacterial infection in children. The upregulation of TXA(2) synthesis may contribute to the process of acute inflammatory reaction caused by bacterial infection.
Copyright 2003 Wiley-Liss, Inc.