Peripheral neutrophils from pregnant women are primed to migrate during parturition by regulators present in the plasma
Thursday, February 13, 2020
5:15 PM – 5:30 PM
Location: Max Bell Auditorium
Introduction: Worldwide, preterm birth is the leading cause of death among children under the age of 5. During preterm/term labor, neutrophils migrate into reproductive tissues in response to chemotactic factors (CF). Neutrophil migration increases as pregnancy progresses. Therefore, we investigated phenotypic changes in neutrophils from women in varying pregnancy stages, as well as non-pregnant neutrophils when exposed to CF and plasma from pregnant women.
Methods: Neutrophils and plasma were obtained from 4 subject groups: nonpregnant (NP; nonpregnant females), control not in labor (CNL; 26-28 weeks pregnant), term not in labor (TNL; term C-section), and spontaneous term labor (STL; spontaneous birth at term); (29 subjects). Cytoskeletal arrangement was assessed via staining of f-actin and visualization using confocal microscopy. CXCR2 expression and morphological changes were assessed on NP neutrophils incubated in plasma and CF, using confocal and brightfield microscopy, respectively. Statistical analysis was performed using GraphPad Prism.
Results: Samples were obtained from healthy female donors from Sanford Medical Center. STL samples had a significantly greater percentage of polarized neutrophils than both CNL and TNL samples (p<0.03, Table 1). When NP neutrophils were incubated with plasma and CF, morphology and CXCR2 expression changed depending on the type of plasma used (Table 2; Table 3). Incubating neutrophils with both plasma and CF activated more neutrophils than either component alone (Table 2). Although the data is not significant, there was a 2.49 fold difference in CXCR2 expression between STL and CNL-treated neutrophils, and a 1.56 fold difference between STL and TNL-treated neutrophils.
Conclusion: CF and factors in plasma play a crucial role in priming neutrophils towards chemotaxis. The morphological changes and increase in CXCR2 expression observed after treatment with plasma and CF strongly suggest that both are required to fully activate neutrophils. Increased morphological changes and f-actin polarization were observed in the STL groups.