Platelet-Neutrophil Interactions Are Lower in Cord Blood of Premature Newborns

Abstract

Objective: To quantify platelet-neutrophil interaction by flow cytometry, in newborn cord blood, as a function of gestational age. Rationale: Little is known about platelet function markers in the newborn, and developmental variations in these markers are not well described. Methods: Cord blood samples were obtained from 64 newborns between 23 and 40 weeks’ gestation. The neonates were grouped into three categories: preterm (< 34 weeks’ gestation, n = 21), late preterm (34 to < 37 weeks’ gestation, n = 22), and term (≥37 weeks’ gestation, n = 21). We monitored the expression of P-selectin and the formation of platelet-neutrophil aggregates (PNAs) by flow cytometry while using adenosine 5′-diphosphate (ADP) or thrombin receptor-activating peptide (TRAP) as agonists. Results: PNAs were significantly lower in preterm compared to term neonates after TRAP or ADP stimulations (11.5 ± 5.2% vs. 19.9 ± 9.1%, p < 0.001, or 24.0 ± 10.1% vs. 39.1 ± 18.2%, p = 0.008, respectively). The expression of P-selectin also tended to be lower in preterm neonates, with significant positive correlations between P-selectin expression and PNA formation. Conclusions: The potential formation of PNAs correlates with gestational age. This suggests that the development of functional competencies of platelets and neutrophils continues throughout gestation, progressively enabling interactions between them.

Platelet Extracellular Vesicles in Cord Blood of Term and Preterm Newborns Assayed by Flow Cytometry: the Effect of Delay in Sample Preparation and of Sample Freezing

“…The correlation of platelet CD62 expression with gestational age was reported previously (Wasiluk et al, 2008), suggesting that lower fluorescence of PEVs after CD62 labelling may reflect its lower expression in preterm new-borns. Recently, lower formation of platelet-neutrophil aggregates in the cord blood of preterm neonates was reported (Esiaba et al, 2019), implying that the CD62 deficit may also have functional consequences. Also, the expression of CD41a, CD42b and CD61 was reported lower on platelets of immature preterm newborns (Sitaru et al, 2005), suggesting that quantitative analysis of PEVs in the cord blood may be complicated by their gestational age-related differences in the expression of platelet markers.…”

Platelets and Immature Neutrophils in Preterm Infants with Feeding Intolerance

“…Our data confirmed the previously reported associations between lower GA at birth, lower BW, chorioamnionitis, and IUGR as risk factors for sepsis and NEC. 13,[40][41][42][43][44] Preterm infants have lower platelet function and less effective neutrophils, [45][46][47] but it is unclear how GA affects platelet and immature neutrophil production at the quantitative level. Maternal chorioamnionitis and IUGR status are also known to influence many hematological indices, such as white blood cell count, neutrophil count, I/T ratio, and platelet count.…”

Platelets in the neonate: Not just a small adult

“… 51 P‐selectin surface expression levels are also lower in activated platelets from (human) preterm compared to term neonates. 49 Consistently, preterm neonates exhibit less platelet‐neutrophil aggregate formation than term neonates following platelet activation with thrombin receptor activating peptide or ADP, 52 a finding that might contribute to the preterm newborn’s susceptibility to infections. Neonates also have a markedly reduced ability to form NETs compared to adults, although this is due to a NET‐inhibitory factor produced by the placenta and present in neonatal blood for 3 to 14 days after birth.…”