The brain of the asphyxiated fetus--basic research

A new animal model for uterine torsion and uterine ischemia-reperfusion studies, but not fetal hypoxia studies

The aim of the present study was to develop a new animal model for use in uterine torsion, uterine ischemia-reperfusion, and fetal hypoxia studies in rats. A total of 14 pregnant rats on their 18th-19th gestational days were used. The animals were randomly divided into two groups: those undergoing the shame operation (group 1), and those in which a 360 uterine torsion was performed using a novel technique, which was corrected 6 hours later (group 2). Subsequently, seven female and seven male rat pups aged 1 month were separated from the mothers in each group. The female rats were monitored until puberty via measuring the vaginal apertures. The 1-month old male rats and the female rats on reaching puberty were decapitated and histopathological tests were performed on the dissected organs, including the cerebral, visceral and genital organs. At the end of the study, no differences were observed between the groups with regard to abortions, offspring death rates and congenital abnormalities. It was observed that the time to reach puberty in female rats born from mothers with uterine torsion was longer, but the difference was statistically insignificant. No microscopic lesions were detected in the cerebral, visceral or genital organs of the offspring. Accordingly, it was concluded that offspring of mothers with the uterine torsion were not affected, at least in the short term. It was generally concluded that this animal model is appropriate for use in uterine torsion and ischemia-reperfusion studies, but is not appropriate for fetal hypoxia studies.

The fetal heart rate response to hypoxia: insights from animal models

This article examines recent studies that have systematically dissected features of fetal heart rate responses to labor that may help identify developing fetal compromise, such as the slope of the deceleration, overshoot, and variability. Although repeated deep decelerations are never necessarily benign, fetuses with normal placental reserve can fully compensate even for frequent deep but brief decelerations for surprisingly prolonged intervals before developing profound acidosis and hypotension.

Associations between serum cortisol, cardiovascular function and neurological outcome following acute global hypoxia in the newborn piglet

Perinatal asphyxia is a significant contributor to neonatal brain injury. However, there is significant variability in neurological outcome in neonates after global hypoxia-ischemia. The aims of this study were to identify which physiological response/s during global hypoxia-ischemia influence the severity of brain injury and to assess their relative importance. Hypoxia/hypercapnia was induced in 20 anaesthetized piglets by reducing the inspired oxygen fraction to 10% and the ventilation rate from 30 to 10 breaths per minute for 45 min. Neurological outcome was assessed using functional markers including cerebral function amplitude (via electroencephalography) and cerebral impedance, and the structural marker microtubule associated protein-2 by immunohistochemistry at 6 h post hypoxia. Significant variability in neurological outcome was observed following the constant hypoxia/hypercapnia insult. There was a high degree of variability in cardiovascular function (mean arterial blood pressure and heart rate) and serum cortisol concentrations in response to hypoxia. More effective maintenance of cardiovascular function and higher serum cortisol concentrations were associated with a better outcome. These two variables were strongly associated with neurological outcome, and together explained 68% of the variation in the severity of neurological outcome. The variability in the cardiovascular and cortisol responses to hypoxia may be a more important determinant of neurological outcome then previously recognized.

Regulation of fetal growth by the somatotrophic axis

Suboptimal fetal growth is associated with higher fetal mortality and with higher neonatal morbidity and mortality. It increases the likelihood of premature birth that in turn further compounds perinatal health risks. Moreover, an abnormal fetal environment, as reflected in an altered birth size phenotype, increases the propensity for disease in childhood and adulthood. Fetal growth represents the culmination of interaction between the fetal genome and the in utero environment determined by maternal-placental function. The role of endocrine and metabolic factors in mediating this interaction will be reviewed. There is also evidence that fetal growth, as measured in late gestation, is dependent not only on the maternal environment but on events that occurred during the periconceptual period. Thus, fetal growth not only reflects the immediate fetal environment but events surrounding conception and embryonic life.

The use of fetal bovine serum: ethical or scientific problem?

Fetal bovine serum (FBS) is a common component of animal cell culture media. It is harvested from bovine fetuses taken from pregnant cows during slaughter. FBS is commonly harvested by means of a cardiac puncture without any form of anaesthesia. Fetuses are probably exposed to pain and/or discomfort, so the current practice of fetal blood harvesting is inhumane. Apart from moral concerns, several scientific and technical problems exist with regard to the use of FBS in cell culture. Efforts should be made to reduce the use of FBS or, preferably, to replace it with synthetic alternatives.

Hypoxic-ischemic brain injury in the newborn: pathophysiology and potential strategies for intervention

There is increasing clinical and experimental data describing the evolution of hypoxic-ischemic encephalopathy in the perinatal period. Outcome to the fetus is determined not only by the impact of gross asphyxial insult, but also external factors that sensitize the brain to injury. Delayed neuronal and glial death occurring in the hours and days after the insult by apoptotic and related processes are observed following severe injury, and offer the most promise for pharmacological intervention. Furthermore, new technologies allow the identification of subtle insults with evolving encephalopathies that have implications for long-term neurological outcome. Application of this knowledge will allow us to identify strategies for early intervention and prevent the course of damage caused by hypoxic-ischemic injury.