Before birth, the lungs are full of fluid that contains a high chloride concentration, little protein, some mucus from the bronchial glands and surfactant from the alveolar epithelial cells (type II). The amount of surfactant in the fluid increases, particularly during the last 2 weeks before birth. As concentration of surfactant increases during the 34th week of gestation, some of this phospholipid enters the amniotic fluid and acts on macrophages in the amniotic cavity. Once “activated”, evidence suggests that these macrophages migrate across the chorion into the uterus where they begin to produce immune system proteins, including interleukin- 1ß (IL-1ß). Upregulation of these proteins results in increased production of prostaglandins that cause uterine contractions. Thus there may be signals from the fetus that participate in the initiating labour and birth. Image 1 High Expression of Pulmonary Proteinase-activated Receptor 2 in Acute and Chronic Lung Injury in Preterm Infants Katariina Cederqvist, Caj Haglund, Päivi Heikkilä, Morley D Hollenberg, Riitta Karikoski and Sture Andersson In the present study they demonstrate that PAR2 is highly expressed in airway epithelium of preterm infants who died of prolonged RDS or of BPD, and that the expression is significantly stronger in comparison with newborn infants without lung pathology The above study concluded that both trypsin-2 and PAR2 can be used as potential therapeutic targets in the setting of RDS and BPD in preterm infants. (A) Newborn infant who died of placental ablation (gestational age 26.1 wk, age at death 2 h). No histologic signs of RDS in postmortem examination. Bar = 50 μm (B) Preterm infant who died of RDS (gestational age 25.0 wk, age at death 2 d). Bar = 50 μm (C) Preterm infant who died of prolonged RDS (gestational age 26.4 wk, age at death 13 d). Bar = 200 μm (D) High-power field of the same patient as in C. Bar = 20 μm. (E) Preterm infant who died of BPD (gestational age 29 wk, age at death 175 d). Bar = 50 μm (F) Immunohistochemical staining for α-smooth muscle actin of the same patient as in E. Bar = 50 μm. Asterisk: fibrotic focus, arrow: alveolar macrophage, as: airspace, br: bronchiole, v: vessel. [Courtesy: Pediatric Research] Image 2 Courtesy SciTechDaily scitechdaily/discovery-could-lead-to-new-treatments-for-lung-disorders-in-premature-babies/
Posted on: Tue, 21 Oct 2014 06:36:25 +0000
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