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

Mechanistic advances of hyperoxia-induced immature brain injury

The impact of hyperoxia-induced brain injury in preterm infants is being increasingly investigated. However, the parameters and protocols used to study this condition in animal models lack consistency. Research is further hampered by the fact that hyperoxia exerts both direct and indirect effects on oligodendrocytes and neurons, with the precise underlying mechanisms remaining unclear. In this article, we aim to provide a comprehensive overview of the conditions used to induce hyperoxia in animal models of immature brain injury. We discuss what is known regarding the mechanisms underlying hyperoxia-induced immature brain injury, focusing on the effects on oligodendrocytes and neurons, and briefly describe therapies that may counteract the effects of hyperoxia. We also identify further studies required to fully elucidate the effects of hyperoxia on the immature brain as well as discuss the leading therapeutic options.

Aligned laminin core-polydioxanone/collagen shell fiber matrices effective for neuritogenesis

Neural tissue regeneration is a significant challenge, because severe nerve injury is quite difficult to regenerate spontaneously. Although, many studies have been devoted to promote nerve regeneration, there are still many technical challenges to achieve satisfactory results. In this study, we designed biomimetic matrices composed of aligned laminin core-polydioxanone/collagen shell (Lam-PDO/Col) fibers, which can provide both topographical and biochemical cues for promoting neuritogenesis. The aligned Lam-PDO/Col core-shell fiber matrices were fabricated by magnetic field-assisted electrospinning with the coaxial system, and their potential as biofunctional scaffolds for promoting neuritogenesis was explored. It was demonstrated that the aligned Lam-PDO/Col core-shell fibers were successfully fabricated, and the laminin in the core of fibers was steadily and continuously released from fibers. In addition, the cellular behaviors of hippocampal neuronal cells on the matrices were significantly enhanced. Moreover, the aligned Lam-PDO/Col fiber matrices effectively improved and guided neurite outgrowth as well as the neurogenic differentiation by providing both topographical and biochemical cues through aligned fiber structure and sustained release of laminin. Collectively, it is suggested that the aligned Lam-PDO/Col core-shell fiber matrices are one of the most promising approaches for promoting neuritogenesis and neural tissue regeneration.

Brain arteriovenous malformations: implications of CEACAM1-positive inflammatory cells and sex on hemorrhage

Brain arteriovenous malformations (bAVMs) are severe conditions which, upon rupture, cause debilitating neurological deficits and even death. The exact cellular and molecular mechanisms associated with bAVM rupture are currently unclear. The objective of this study was to explore the potential role of CEA-related cell adhesion molecule-1 (CEACAM1) in bAVM pathophysiology. Expression and localization of CEACAM1 were assessed immunohistochemically in tissue microarrays from bAVM patients (n = 60). The association of CEACAM1 with clinical parameters was analyzed with Spearman's rank correlation coefficient and chi-square test. The predictive value of CEACAM1 was tested using logistic regression analysis. CEACAM1 was highly expressed in tissue-infiltrating neutrophil granulocytes. High levels of CEACAM1-positive cells were associated with bAVM rupture (hemorrhage), but not with arteriovenous malformation (AVM) size, preoperative embolization, or seizure. This association was significant (p = 0.029, chi-square) in male but not in female patients, and high CEACAM1-positive immune infiltration showed predictive significance for hemorrhage in male bAVM patients only (OR = 6.50, 95 % CI 1.09-38.63, p = 0.040). Within the ruptured bAVM group, patients with a short hemorrhage to surgery (HTS) time interval had higher levels of CEACAM1 immune infiltration than patients with long HTS. This decrease in the levels of CEACAM1 immune infiltration between the HTS short and HTS long groups was, however, significant only in female patients (p = 0.022, chi-square). Our findings substantiate the role of inflammation in the pathophysiology of bAVM and suggest the presence of sexual dimorphism in this disease.

Tumor necrosis factor-inducible gene 6 protein: A novel neuroprotective factor against inflammation-induced developmental brain injury

Inflammation is an important factor contributing to developmental brain injury in preterm infants. Although tumor necrosis factor-inducible gene 6 protein (TSG-6) has immunomodulatory effects in several inflammatory conditions of adult animals, nothing is currently known about the role of TSG-6 in the developing brain, its impact on perinatal inflammation and its therapeutic potential. The aim of the current work was 1) to characterize the developmental expression of TSG-6 in the newborn rat brain, 2) to evaluate the impact of LPS exposure on TSG-6 expression and 3) to assess the therapeutic potential of exogenous TSG-6 administration. Brain hemispheres of healthy Wistar rats (postnatal day 1-postnatal day 15 (P1-P15)) were evaluated with regard to the physiological expression of TSG-6. LPS-treated rats (0.25mg/kg LPS i.p. on P3) were analyzed for inflammation-induced changes in TSG-6 and cytokine expression. To evaluate whether exogenous recombinant human (rh)TSG-6 affects inflammation-induced brain injury, newborn Wistar rats, exposed to LPS on P3, were treated with rhTSG-6 i.p. (four repetitive doses of 2.25mg/kg every 12h, first dose 3h before LPS injection). PCR, Western blotting and multiplex ELISA were performed according to standard protocols. TSG-6 is physiologically expressed in the developing brain with a linear increase in expression from P1 to P15 at the mRNA level. At P6, regional differences in TSG-6 expression in the cortex, thalamus and striatum were detected at mRNA and protein level. Furthermore, TSG-6 gene expression was significantly increased by inflammation (induced by LPS treatment). Combined treatment with LPS and TSG-6 vs. LPS exposure alone, resulted in significant down-regulation of cleaved caspase-3, a marker of apoptosis and neuronal plasticity. In addition, several inflammatory serum markers were decreased after TSG-6 treatment. Finally, TSG-6 is physiologically expressed in the developing brain. Changes of TSG-6 expression associated with inflammation suggest a role of TSG-6 in neuroinflammation. Reduction of cleaved caspase-3 by TSG-6 treatment demonstrates the putative neuroprotective potential of exogenous TSG-6 administration in inflammation-induced developmental brain injury.