Transfusion-related Inflammatory Cytokine and Neutrophil Extracellular Trap Quantification in Neonates

University of Utah12 enrolled

Overview

Despite many advances in neonatal care, necrotizing enterocolitis (NEC) remains a leading cause of morbidity and mortality among premature infants. NEC is the most common life-threatening gastrointestinal emergency encountered in the neonatal intensive care unit, affecting between 3.8% and 13% of very low birthweight (VLBW) infants (1-3). More recently interest has intensified regarding the possible association between "elective" red blood cell (RBC) transfusions in premature infants and the subsequent development of NEC (4-9). On a physiological basis, a few explanations for transfusion-associated NEC have been proposed: 1) the physiological impact of anemia that can initiate a cascade of events leading to ischemic-hypoxemic mucosal gut injury predisposing to NEC \[10\]; and 2) increased splanchnic blood flow following RBC transfusion leading to reperfusion injury of gut mucosa. Aim 1. This study will quantify inflammatory cytokine profiles in anemic infants cared for in the NICU prior to and after transfusion with packed red blood cells (PRBC), as dictated by current clinical guidelines for treatment of anemia, and prospectively assess for clinical signs and symptoms of NEC following each transfusion event. Aim 2. Polymorphonuclear leukocytes (PMNs) isolated from the pre- and post-transfusion blood samples will be assessed in vitro for neutrophil extracellular traps (NET) formation. Aim 3. A) To determine whether significant anemia preceding a RBC transfusion is associated with impaired intestinal oxygenation, and whether a RBC transfusion temporarily increases splanchnic oxygenation. We postulate that the CSOR will be low (\<0.75) at baseline measurement in infants with hemodynamically significant anemia, and that RBC transfusion will temporarily increase intestinal perfusion in that particular group of babies. B) To determine whether alterations in mesenteric regional oxygenation saturation(rSO2) can predict the development of NEC in VLBW infants. We hypothesize that overall cerebro-splanchnic oxygenation ratio (CSOR) values will be significantly lower among very low birth weight (VLBW) infants that develop NEC, when compared to CSOR values obtained in infants that do not develop NEC following RBC transfusion.

Study Type

OBSERVATIONAL

Enrollment

Conditions

Outcomes

Primary Outcomes

Serum cytokine content

Plasma samples will be analyzed for the protein content of 13 different cytokines via a multiplexed sandwich capture assay performed at the ARUP Institute for Experimental and Clinical Pathology. The cytokines and chemokines assayed will include: CD40 ligand, interferon-gamma, interleukin-10, interleukin-12, interleukin-13, interleukin-1-β, interleukin-2, interleukin-2-receptor, interleukin-4, interleukin-5, interleukin-6, IL-8, and Tumor Necrosis Factor-alpha. In addition, we will assay components of the complement pathway including: total hemolytic complement, C3a, C5a, and FAB fragments in the alternative complement pathway. Cytokine protein levels before and after transfusion will be compared to each other and to the PRBC sample cytokine content.

Time frame: 6 hrs

Secondary Outcomes

Assessment of NET formation

PMNs will be isolated from the participant blood samples following removal of the plasma via positive immunoselection. They will then be stimulated in vitro with NET-inducing stimuli such as lipopolysaccharide or platelet-activating factor for 1 hour under standard conditions and assayed for NET formation both qualitatively via confocal microscopy and quantitatively via histone H3 supernatant content as determined by ELISA and/or western blotting.