The Expression of Pathologic Reticulocyte Adhesion Proteins in Premature Infants and its Role in Necrotizing Enterocolitis. † 958

Abstract

Prematurity is recognized as the primary risk factor which predisposes infants to necrotizing enterocolitis (NEC). However, the pathophysiology of NEC is poorly understood. Recent studies in sickle cell anemia suggest that the expression of adhesive proteins on reticulocytes may result in pathologic red cell binding to endothelial cells (EC). The resultant vascular occlusion may occur via an α4β1 integrin binding to the TNF induced EC ligand VCAM-1. To address whether this mechanism may play a role in NEC, we determined whether erythrocytes from premature infants express theα4β1 integrin complex. Blood specimens from premature infants (mean age 28 wks, range 23-32 wks) were examined for expression of α4β1 utilizing flow cytommetry. Bowel specimens from patients with NEC were examined for VCAM-1 by immunohistochemistry. Data are expressed as mean± SEM. Statistical analysis was performed by Student's unpaired t-test. Premature infants (n=40) had both increased circulating reticulocytes andα4β1 expression verses normal term control infants (n=20, p<.001). This expression was consistent with the integrin expression observed in patients with NEC (n=20). Table