ABSTRACT
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ABSTRACT
Antenatal inflammation as seen with chorioamnionitis is harmful to foetal/neonatal organ development including to eyes. Although the major pro-inflammatory cytokine IL-1ß participates in retinopathy induced by hyperoxia (a predisposing factor to retinopathy of prematurity), the specific role of antenatal IL-1ß associated with preterm birth (PTB) in retinal vasculopathy (independent of hyperoxia) is unknown. Using a murine model of PTB induced with IL-1ß injection in utero, we studied consequent retinal and choroidal vascular development; in this process we evaluated the efficacy of IL-1R antagonists. Eyes of foetuses exposed only to IL-1ß displayed high levels of pro-inflammatory genes, and a persistent postnatal infiltration of inflammatory cells. This prolonged inflammatory response was associated with: (1) a marked delay in retinal vessel growth; (2) long-lasting thinning of the choroid; and (3) long-term morphological and functional alterations of the retina. Antenatal administration of IL-1R antagonists - 101.10 (a modulator of IL-1R) more so than Kineret (competitive IL-1R antagonist) - prevented all deleterious effects of inflammation. This study unveils a key role for IL-1ß, a major mediator of chorioamnionitis, in causing sustained ocular inflammation and perinatal vascular eye injury, and highlights the efficacy of antenatal 101.10 to suppress deleterious inflammation.
Subject(s)
Inflammation/metabolism , Interleukin-1beta/metabolism , Retina/metabolism , Retinal Diseases/metabolism , Retinal Vessels/metabolism , Animals , Chorioamnionitis/metabolism , Choroid/metabolism , Disease Models, Animal , Female , Hyperoxia/metabolism , Interleukin 1 Receptor Antagonist Protein/metabolism , Mice , Pregnancy , Receptors, Interleukin-1/metabolismABSTRACT
Preterm birth (PTB) is a leading cause of neonatal mortality and morbidity worldwide, and surviving infants are at increased risks of lifelong complications. PTB has been firmly linked to inflammation regardless of infection, specific aetiology or timing of birth. Deleterious inflammation is observed in maternal and fetal tissue, and correlates with the severity of perinatal complications. At present, PTB is treated with tocolytics as though it is exclusively a myometrial contractile disorder. These agents do not address underlying inflammatory processes and are thus vastly ineffective at improving neonatal outcomes. Of all inflammatory mediators, IL-1 is central to the pathophysiology of PTB and most adverse neonatal outcomes. We thus present herein a review of the various effects of IL-1 in utero, with a brief overview of its mechanism of action. We then discuss the potential of different IL-1-targeting agents based on pre-clinical testing in relevant models of PTB and neonatal inflammatory injuries.
Subject(s)
Inflammation/drug therapy , Interleukin-1/antagonists & inhibitors , Premature Birth , Receptors, Interleukin-1/antagonists & inhibitors , Animals , Female , Inflammation/metabolism , Inflammation/pathology , Interleukin-1/metabolism , Pregnancy , Receptors, Interleukin-1/metabolismABSTRACT
Preterm birth (PTB) is commonly accompanied by in utero fetal inflammation, and existing tocolytic drugs do not target fetal inflammatory injury. Of the candidate proinflammatory mediators, IL-1 appears central and is sufficient to trigger fetal loss. Therefore, we elucidated the effects of antenatal IL-1 exposure on postnatal development and investigated two IL-1 receptor antagonists, the competitive inhibitor anakinra (Kineret) and a potent noncompetitive inhibitor 101.10, for efficacy in blocking IL-1 actions. Antenatal exposure to IL-1ß induced Tnfa, Il6, Ccl2, Pghs2, and Mpges1 expression in placenta and fetal membranes, and it elevated amniotic fluid IL-1ß, IL-6, IL-8, and PGF2α, resulting in PTB and marked neonatal mortality. Surviving neonates had increased Il1b, Il6, Il8, Il10, Pghs2, Tnfa, and Crp expression in WBCs, elevated plasma levels of IL-1ß, IL-6, and IL-8, increased IL-1ß, IL-6, and IL-8 in fetal lung, intestine, and brain, and morphological abnormalities: e.g., disrupted lung alveolarization, atrophy of intestinal villus and colon-resident lymphoid follicle, and degeneration and atrophy of brain microvasculature with visual evoked potential anomalies. Late gestation treatment with 101.10 abolished these adverse outcomes, whereas Kineret exerted only modest effects and no benefit for gestation length, neonatal mortality, or placental inflammation. In a LPS-induced model of infection-associated PTB, 101.10 prevented PTB, neonatal mortality, and fetal brain inflammation. There was no substantive deviation in postnatal growth trajectory or adult body morphometry after antenatal 101.10 treatment. The results implicate IL-1 as an important driver of neonatal morbidity in PTB and identify 101.10 as a safe and effective candidate therapeutic.
