Indomethacin Prophylaxis Is Associated with Reduced Risk of Intraventricular Hemorrhage in Extremely Preterm Infants Born in the Context of Amniotic Infection Syndrome.

BACKGROUND: Amniotic infection syndrome (AIS) with perinatal inflammation may increase the susceptibility to intraventricular hemorrhage (IVH) in preterm infants. Given its anti-inflammatory and ductus arteriosus constricting capacities, we hypothesized that prophylactic administration of indomethacin reduces the incidence, severity, and consequences of IVH in the context of perinatal inflammation. METHODS: We evaluated data of infants born between 2009 and 2020 of 22 + 0-25+6 weeks of gestation from 68 German Neonatal Network centers. The effect of indomethacin prophylaxis on outcomes was analyzed in univariate analyses and multivariate regression models including a subgroup of infants with available data on 5-year follow-up. RESULTS: 4760 infants were included with a median gestational age of 24.6 SSW [interquartile range (IQR) 24.1w-25.2w] and a birth weight of 640 g [IQR 550-750 g]. 1767/4760 (37.1%) preterm infants were born in the context of AIS and 527/4760 (11.1%) received indomethacin prophylaxis. AIS infants receiving prophylactic indomethacin had lower rates of IVH (32.7% vs. 36.9%, p = 0.04), IVH III/IV (9.7% vs. 16.0%, p = 0.02) and the combined outcome of severe IVH or death (15.9% vs. 23.2%, p = 0.01) as compared to infants without prophylaxis. Multivariate logistic regression analyses confirmed our observations. In a subgroup analysis of 730 preterm infants at 5 years of age, we did not find any correlation between prophylactic indomethacin and intelligence quotient <70 or cerebral palsy. CONCLUSIONS: Our observational data demonstrate that prophylactic indomethacin is associated with a reduced risk of IVH in the highly vulnerable subgroup of preterm infants <26 weeks of gestation born from AIS.

Soluble CEACAM1 and CEACAM6 are differently expressed in blood serum of pregnant women during normal pregnancy.

PROBLEM: CEACAM1 and CEACAM6 belong to the carcinoembryonic antigen (CEA) family and may play an immune-modulatory role during pregnancy. The aim of the study was to determine the blood serum levels of soluble CEACAM1 and CEACAM6 over the course of pregnancy and postpartum. METHOD OF STUDY: CEACAM1 and CEACAM6 levels were determined with customized in-house Sandwich-enzyme-linked immunosorbent assay (ELISA) systems. The study population (n=125) was divided into four groups according to the pregnancy trimester and postpartum. Additionally, samples of non-pregnant women (n=14) were analyzed. RESULTS: Serum levels of CEACAM1 in healthy pregnant women were much lower than in non-pregnant women, a difference not seen for CEACAM6. Comparison between the trimesters and postpartum revealed a significant difference in CEACAM1 serum levels. The highest CEACAM1 levels were detected in third trimester. These levels were statistically significantly different from the CEACAM1 levels in first trimester and second trimester. The lowest levels were observed in the second trimester. Postpartum CEACAM1 serum concentrations were slightly lower than in the third trimester, but higher than in the first trimester and significantly higher compared to levels in the second trimester. CONCLUSION: Decreased concentration of CEACAM1 during the pregnancy suggests its regulatory role in the immune tolerance during the course of pregnancy.

Mesenchymal stem cell-derived extracellular vesicles ameliorate inflammation-induced preterm brain injury.

OBJECTIVE: Preterm brain injury is a major cause of disability in later life, and may result in motor, cognitive and behavioural impairment for which no treatment is currently available. The aetiology is considered as multifactorial, and one underlying key player is inflammation leading to white and grey matter injury. Extracellular vesicles secreted by mesenchymal stem/stromal cells (MSC-EVs) have shown therapeutic potential in regenerative medicine. Here, we investigated the effects of MSC-EV treatment on brain microstructure and maturation, inflammatory processes and long-time outcome in a rodent model of inflammation-induced brain injury. METHODS: 3-Day-old Wistar rats (P3) were intraperitoneally injected with 0.25mg/kg lipopolysaccharide or saline and treated with two repetitive doses of 1×108 cell equivalents of MSC-EVs per kg bodyweight. Cellular degeneration and reactive gliosis at P5 and myelination at P11 were evaluated by immunohistochemistry and western blot. Long-term cognitive and motor function was assessed by behavioural testing. Diffusion tensor imaging at P125 evaluated long-term microstructural white matter alterations. RESULTS: MSC-EV treatment significantly ameliorated inflammation-induced neuronal cellular degeneration reduced microgliosis and prevented reactive astrogliosis. Short-term myelination deficits and long-term microstructural abnormalities of the white matter were restored by MSC-EV administration. Morphological effects of MSC-EV treatment resulted in improved long-lasting cognitive functions INTERPRETATION: MSC-EVs ameliorate inflammation-induced cellular damage in a rat model of preterm brain injury. MSC-EVs may serve as a novel therapeutic option by prevention of neuronal cell death, restoration of white matter microstructure, reduction of gliosis and long-term functional improvement.

Endogenous hypothermic response to hypoxia reduces brain injury: Implications for modeling hypoxic-ischemic encephalopathy and therapeutic hypothermia in neonatal mice.

Hypothermia treatment (HT) is the only formally endorsed treatment recommended for hypoxic-ischemic encephalopathy (HIE). However, its success in protecting against brain injury is limited with a number to treat of 7-8. The identification of the target mechanisms of HIE in combination with HT will help to explain ineffective therapy outcomes but also requires stable experimental models in order to establish further neuroprotective therapies. Despite clinical and experimental indications for an endogenous thermoregulatory response to HIE, the potential effects on HIE-induced brain injury have largely been neglected in pre-clinical studies. In the present study we analyzed gray and white matter injury and neurobehavioral outcome in neonatal mice considering the endogenous thermoregulatory response during HIE combined with HT. HIE was induced in postnatal day (PND) 9 C57BL/6 mice through occlusion of the right common carotid artery followed by one hour of hypoxia. Hypoxia was performed at 8% or 10% oxygen (O2) at two different temperatures based on the nesting body core temperature. Using the model which mimics the clinical situation most closely, i.e. through maintenance of the nesting temperature during hypoxia we compared two mild HT protocols (rectal temperature difference 3°C for 4h), initiated either immediately after HIE or with delay of 2h. Injury was determined by histology, immunohistochemistry and western blot analyses at PND 16 and PND 51. Functional outcome was evaluated by Rota Rod, Elevated Plus Maze, Open Field and Novel Object Recognition testing at PND 30-PND 36 and PND 44-PND 50. We show that HIE modeling in neonatal mice is associated with a significant endogenous drop in body core temperature by 2°C resulting in profound neuroprotection, expressed by reduced neuropathological injury scores, reduced loss of neurons, axonal structures, myelin and decreased astrogliosis. Immediately applied post-hypoxic HT revealed slight advantages over a delayed onset of therapy on short- and long-term histological outcome demonstrated by reduced neuropathological injury scores and preservation of hippocampal structures. However, depending on the brain region analyzed neuroprotective effects were similar or even reduced compared to protection by endogenous cooling during HIE modeling. Moreover, long-term neurobehavioral outcome was only partially improved for motoric function (i.e. Rota Rod performance and rearing activity) while cognitive deficits (i.e. novel object recognition) remained unchanged. These findings emphasize the need to maintain the nesting temperature during the initiation of the pathological insult and highlight the urgency to develop and assess new adjuvant therapies for HT in well-defined experimental models.

CEACAM1 expression in oligodendrocytes of the developing rat brain shows a spatiotemporal relation to myelination and is altered in a model of encephalopathy of prematurity.

CEACAM1 is the founder molecule of the family of 'carcinoembryonic antigen-related cell adhesion molecules' and part of the immunoglobulin superfamily. Due to its role as a coreceptor to many other receptors (e.g. Toll-like receptor 2, Toll-like receptor 4, T-cell receptor, B-cell receptor, epidermal growth factor receptor and vascular endothelial growth factor receptor) and its different isoforms, CEACAM1 is a multifunctional protein with an impact on proliferation and differentiation of multiple cell types. Although different modes of action in other tissues are described, the role of CEACAM1 in the developing brain remains elusive. Here we report for the first time that CEACAM1 is expressed ontogenetically in oligodendrocytes of the developing rat brain, and that CEACAM1 expression has a spatiotemporal relation to myelination. In addition, CEACAM1 expression is altered in a model of hyperoxia- and inflammation-induced encephalopathy of prematurity, a myelination disorder of children born preterm. Furthermore, primary oligodendrocytes stimulated with CEACAM1 show increased myelination. Therefore, we postulate that CEACAM1 is, at least in part, involved in hyperoxia- and inflammation-induced disruption of myelination, but may also play a role in intact myelination as it is ontogenetically expressed in myelinating oligodendrocytes.

Interaction of inflammation and hyperoxia in a rat model of neonatal white matter damage.

Intrauterine infection and inflammation are major reasons for preterm birth. The switch from placenta-mediated to lung-mediated oxygen supply during birth is associated with a sudden rise of tissue oxygen tension that amounts to relative hyperoxia in preterm infants. Both infection/inflammation and hyperoxia have been shown to be involved in brain injury of preterm infants. Hypothesizing that they might be additive or synergistic, we investigated the influence of a systemic lipopolysaccharide (LPS) application on hyperoxia-induced white matter damage (WMD) in newborn rats. Three-day-old Wistar rat pups received 0.25 mg/kg LPS i.p. and were subjected to 80% oxygen on P6 for 24 h. The extent of WMD was assessed by immunohistochemistry, western blots, and diffusion tensor (DT) magnetic resonance imaging (MRI). In addition, the effects of LPS and hyperoxia were studied in an in vitro co-culture system of primary rat oligodendrocytes and microglia cells. Both noxious stimuli, hyperoxia, and LPS caused hypomyelination as revealed by western blot, immunohistochemistry, and altered WM microstructure on DT-MRI. Even so, cellular changes resulting in hypomyelination seem to be different. While hyperoxia induces cell death, LPS induces oligodendrocyte maturity arrest without cell death as revealed by TUNEL-staining and immunohistological maturation analysis. In the two-hit scenario cell death is reduced compared with hyperoxia treated animals, nevertheless white matter alterations persist. Concordantly with these in vivo findings we demonstrate that LPS pre-incubation reduced premyelinating-oligodendrocyte susceptibility towards hyperoxia in vitro. This protective effect might be caused by upregulation of interleukin-10 and superoxide dismutase expression after LPS stimulation. Reduced expression of transcription factors controlling oligodendrocyte development and maturation further indicates oligodendrocyte maturity arrest. The knowledge about mechanisms that triggered hypomyelination contributes to a better understanding of WMD in premature born infants.

Searching for genomic variants in IGF2 and CDKN1C in Silver-Russell syndrome patients.

Silver-Russell syndrome (SRS) is a heterogeneous syndrome with evidence for a substantial role of genetic factors in its etiology. Apart from other specific clinical features, severe intrauterine and postnatal growth retardation are the dominant characteristics of SRS. Therefore, studies on the genetic basis of the disease focus on genes involved in growth and its regulation. Another key for the identification of (a) SRS gene(s) is the finding of chromosomal disturbances in SRS patients: recently, four growth retarded patients carrying duplications in 11p15 of maternal origin have been described, two of these cases presented SRS-like features. The same region includes IGF2 and CDKN1C and is well known to harbour alterations in patients suffering from Beckwith-Wiedemann syndrome. We therefore decided to perform an extensive search for variants in the IGF2 and CDKN1C genes; mutations in these genes cause growth disturbances. More than 40 SRS patients were screened for mutations by different detection strategies, allele frequencies were compared between patients and controls. In both genes, we did not detect any obvious pathogenic mutation. In case of IGF2, slight differences in the allelic distribution of specific polymorphisms between SRS patients and controls were observed. In CDKN1C, several variants could be identified in both cohorts with similar frequencies, but only one patient showed a so far unknown variant not detectable in controls.

Characterization of genomic variants in CSH1 and GH2, two candidate genes for Silver-Russell syndrome in 17q24-q25.

Silver-Russell syndrome (SRS) is a syndrome of severe pre- and postnatal growth retardation and typical dysmorphic features. Rare chromosomal aberrations have been reported in SRS; among these are two balanced translocations involving 17q24-q25. Recently, we described a patient with a paternally inherited heterozygous deletion of the chorionic somatomammotropin hormone 1 (CSH1) gene. The CSH1 gene is member of the growth hormone (GH) gene cluster on 17q, which consists of two growth hormone genes and three CSH genes. Genomic alterations in the GH cluster are well known, causing different phenotypes depending on the size of the deletion and the genes involved. By screening 63 SRS cases with marker D17S254, we have detected 2 further patients with a heterozygous deletion in the GH cluster. Quantitative analysis using restriction assays confirmed these findings. Additionally, in a cohort of 17 patients with isolated intrauterine and postnatal growth retardation, we detected a further patient to be carrier of a CSH1 deletion. Screening of 141 unrelated controls revealed hemizygosity in one person for which data on growth were not available. We additionally analyzed our cohort of SRS patients for mutations in CSH1 and its 3' neighbour GH2. However, analyses failed to reveal any pathogenic mutation. While the central role of GH1 in human growth is well established, the physiological roles of CSH1 and other components of the cluster are unclear. The increased prevalence of hemizygosity of CSH1 in our population in comparison to controls indicates a role for CSH1 haploinsufficiency in the etiology of growth retardation. Investigation of CSH1 deletions in further SRS and growth retarded patients will enable us to establish under which circumstances haploinsufficiency of CSH1 is likely to result in clinical changes.