Abstract Number: OC 20.2
Meeting: ISTH 2021 Congress
Background: Intraventricular hemorrhage (IVH) is a severe complication of prematurity, when RBC destruction with accumulation of heme can induce inflammation and cellular dysfunction in subarachnoid space. Hypoxia of germinal matrix also contributes to these alterations. We have recently reported elevated pro-inflammatory miRNAs in cerebrospinal fluid (CSF) samples of preterm IVH infants in correlation with high heme and soluble adhesion molecules.
Aims: Here, we investigated IVH induced inflammatory events in human choroid plexus epithelial cells (HCPEpiC) in vitro.
Methods: HCPEpiC cell cultures were exposed to IVH CSF vs. control samples (10 v/v %) for 24 hours. To observe the direct effect of hemorrhage, cells were treated with heme (25 μM) or TNF-α (100 ng/mL) for 1-24 hours. Treatment with hypoxia was mimicked using CoCl2 (100 μM) with or without heme. RNA was extracted to quantify specific mRNAs as well as miR-155 and miR-223 intracellularly and in the supernatants by RT-qPCR. Soluble IL-8 and ICAM-1 were measured by ELISA. Nuclear translocation of NF-κB p65 subunit was investigated with fluorescence microscopy.
Results: HCPEpiCs were activated by IVH CSF showing significant elevation in HMOX1, IL8, IL1B and ICAM1 mRNAs vs. controls. Similarly, there was a time-dependent up-regulation of these genes after stimulation with heme. Furthermore, significantly elevated protein levels of IL-8 and ICAM-1 were observed similar to TNF-α. Both mediators induced the nuclear translocation of NF-κB p65 subunit. Although CoCl2 alone induced hypoxia response genes VEGFA and GLUT1 with enhanced IL1B and IL8 levels, but no additive effect was observed to heme. miR-155 and miR-223 were elevated in the supernatants by heme and TNF-α that underlines our former results in IVH CSF. In contrast, decreased intracellular miR-223 was related to up-regulated ICAM1 expression in HCPEpiCs.
Conclusions: In IVH, choroid plexus epithelial cells are highly affected by different consequences of bleeding that may contribute to the development of clinical complications.
To cite this abstract in AMA style:Fejes Z, Pócsi M, Balla A, Balogh E, Tóth A, Jeney V, Rusznyák Á, Fenyvesi F, Nagy A, Kappelmayer J, BN. Investigation of Preterm Intraventricular Hemorrhage Induced Inflammatory Response and microRNA Levels by Heme and Hypoxia in Human Choroid Plexus Epithelial Cells [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 1). https://abstracts.isth.org/abstract/investigation-of-preterm-intraventricular-hemorrhage-induced-inflammatory-response-and-microrna-levels-by-heme-and-hypoxia-in-human-choroid-plexus-epithelial-cells/. Accessed September 24, 2021.
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