Recent advances in neonatology

The role of β-catenin signaling pathway on proliferation of rats neural stem cells after hyperbaric oxygen therapy in vitro

β-catenin, a protein that functions in both cell adhesion and Wnt signaling, plays a key role in mammalian neural development. To investigate the role of β-catenin in hyperbaric oxygen therapy (HBO)-induced neurogenesis after hypoxic ischemic brain damage (HIBD), we transfected β-catenin siRNA and negative control siRNA into neural stem cells (NSCs) after HIBD. We found that HBO promoted NSCs differentiate into neurons or oligodendrocytes, and inhibited NSCs differentiate into astrocytes; HIBD brain tissue extract conditioned cultures promoted NSCs differentiate into neurons; β-Catenin siRNA decreased the NSE-positive neurons and increased GFAP-positive astrocytes in the NSCs in vitro. Furthermore, the expression of Ngn1 protein and mRNA in NSCs was increased when HBO promoted NSCs differentiate into neurons after HIBD, and the expression of BMP-4 protein and mRNA was decreased when HBO depressed NSCs differentiate into astrocytes after HIBD. These results showed that β-catenin-mediated transcriptional activation functions in the decision of NSCs to proliferate neurogenesis during HBO-induced after HIBD, and suggested that HBO therapy promotes the proliferation of neural stem cells in vitro, an effect that may be correlated with β-catenin protein and HBO therapy could promote neurogenesis by β-catenin-induced activated Ngn1 gene and repress astrocytogenesis by β-catenin-induced down-regulated BMP-4 gene.

Proliferation of neural stem cells correlates with Wnt-3 protein in hypoxic-ischemic neonate rats after hyperbaric oxygen therapy

Hyperbaric oxygen therapy promoted brain cell proliferation. Wnt-3 is closely associated with the proliferation of neural stem cells. We examined whether hyperbaric oxygen promoted neural stem cells to proliferate and its correlation with Wnt-3 protein in hypoxic-ischemic neonate rats. Hyperbaric oxygen therapy was administered 3 h after hypoxia ischemia daily for 7 days. The proliferating stem cells and Wnt-3 protein were examined dynamically in the subventricular zone. Results showed that stem cells proliferated and peaked 7 days after hyperbaric oxygen therapy. Wnt-3 protein increased to the higher levels 3 days after therapy. Linear regression analysis showed that nestin protein correlated with Wnt-3 protein. We propose that hyperbaric oxygen treatment promote stem cells to proliferate, which is correlated with Wnt-3 protein.

Brain injury in the infant: the old, the new, and the uncertain

Although neonatal brain injury occurs most frequently after a perinatal hypoxic-ischemic insult, recently studies have noted that variable causes such as metabolic and reperfusion events can result in, or aggravate, a brain insult. Current data suggest that about 2 to 5 of 1,000 live births in the United States and more so in developing countries experience a brain injury Approximately 20% to 40% of infants who survive the brain injury develop significant neurological and developmental impairments. The resulting impact on the child, family, and society presents a formidable challenge to health care professionals. Although several important insights have been gained in the last several years about the epidemiology, diagnosis, and mechanism of brain injury, management remains mostly a cocktail of controversial trials. This article provides a comprehensive review of the pathology, clinical manifestations, and timely management of infants with brain injury.

Effect of hyperbaric oxygen on apoptosis in neonatal hypoxia-ischemia rat model

We have previously demonstrated that a transient exposure to hyperbaric oxygen (HBO) attenuated the neuronal injury after neonatal hypoxia-ischemia. This study was undertaken to determine whether HBO offers this neuroprotection by reducing apoptosis in injured brain tissue. Seven-day-old rat pups were subjected to unilateral carotid artery ligation followed by 2 h of hypoxia (8% oxygen). Apoptotic cell death was examined in the injured cortex and hippocampus tissue. Caspase-3 expression and activity increased at 18 and 24 h after the hypoxia-ischemia insult. At 18-48 h, poly(ADP-ribose) polymerase (PARP) cleavage occurred, which reduced the band at 116 kDa and enhanced the band at 85 kDa. There was a time-dependent increase in the number of terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL)-positive cells. A single HBO treatment (100% oxygen, 3 ATA for 1 h) 1 h after hypoxia reduced the enhanced caspase-3 expression and activity, attenuated the PARP cleavage, and decreased the number of TUNEL-positive cells observed in the cortex and hippocampus. These results suggest that the neuroprotective effect of HBO is at least partially mediated by the reduction of apoptosis.

Mechanisms of erythropoietin-induced brain protection in neonatal hypoxia-ischemia rat model

Erythropoietin, a hemotopoietic growth factor, has brain protective actions. This study investigated the mechanisms of Recombinant Human EPO (rhEPO)-induced brain protection in neonates. An established rat hypoxia-ischemia model was used by ligation of the right common carotid artery of 7-day-old pups, followed by 90 minute of hypoxia (8% 02 and 92% N2) at 37 degrees C. Animals were divided into three groups: control, hypoxia-ischemia, and hypoxia-ischemia plus rhEPO treatment. In rhEPO treated pups, 300 units rhEPO was administered intraperitoneally 24 hours before hypoxia. rhEPO treatment (300 units) was administered daily for an additional 2 days. ELISA and immunohistochemistry examined the expression of EPO and EPOR. Brain weight, morphology, TUNEL assay, and DNA laddering evaluated brain protection. rhEPO abolished mortality (from 19% to 0%) during hypoxia insult, increased brain weight from 52% to 88%, reduced DNA fragmentation, and decreased TUNEL-positive cells. Real-time RT-PCR, Western blot, and immunohistochemistry revealed an enhanced expression of heat shock protein 27 (HSP27) in ischemic brain hemisphere. Double labeling of TUNEL with HSP27 showed most HSP27 positive cells were negative to TUNEL staining. rhEPO reduces brain injury, especially apoptotic cell death after neonatal hypoxia-ischemia, partially mediated by the activation of HSP27.

Views of bereaved multiple-birth parents on life support decisions, the dying process, and discussions surrounding death

OBJECTIVE

This study assessed the experiences of bereaved parents of multiples with resuscitation and life-support discussions, the death process, and conversations with health-care professionals about death.

STUDY DESIGN

In all, 71 bereaved parents of multiples recruited from Internet support groups completed a narrative e-mail survey assessing many facets of bereavement. Numeric data were analyzed using simple quantitative analysis, with a grounded theory approach used for qualitative data.

RESULTS

Most decisions were collaborative, with occasional directive comments. Some decisions were made during crises. Occasionally, parents initiated life-support discussions. Multidisciplinary meetings occurred with 30%, but were desired by more parents. A total of 18% of parents encountered criticism of choices. Most parents attended resuscitation, and found meaning in holding their dying children. Many desire privacy, availability of symptom management, and family or clergy involvement. Photographs of multiples together are valued. Parents offered many suggestions for compassionate death notification, which most felt should occur in person if parents are not present for the death. Respondents valued clear, prompt discussion of the cause of death, and clinician availability for later review of clinical events or decisions.

CONCLUSIONS

Multiple-birth parents' choices resemble those of singleton parents at the end of an infant's life.