Low vascularization of the nephrogenic zone of the fetal kidney suggests a major role for hypoxia in human nephrogenesis.

CD31 reactivity is generally utilized as a marker of endothelial cells. CD31 immunoreactivity in the developing human kidney revealed that fetal glomerular capillary endothelial cells change their immunohistochemical phenotype during maturation. The aim of this study was to analyze CD31 reactivity in the fetal human kidney in the different stages of intrauterine development: We observed different distribution of CD31-reactive vascular progenitors in the different areas of the developing kidney. In particular, the nephrogenic zone and the renal capsule were characterized by a scarcity of CD31-reactive cells at all gestational ages. These data suggest the hypothesis that nephrogenesis does not need high oxygen levels and confirms a major role of hypoxia in nephrogenesis.

WT1 expression in the human fetus during development.

Wilms' Tumor 1 (WT1) is a transcription factor involved in the development of the urogenital system. The purpose of this study was to analyze the immunoreactivity for WT1 protein in different tissues and organs in human fetuses in early phases of gestation. To this end, samples from multiple organs were obtained from 4 human fetuses, ranging from 7 up to 12 weeks of gestation. Each sample was formalin-fixed, paraffin embedded and immunostained for WT1. Our data show that WT1 is involved in development of multiple human organs in a more vast series of cells types than previously reported. Immunostaining for WT1 was characterized by a predominant cytoplasmic reactivity in the vast majority of cell types. Mesenchimal progenitors in the fetal lung, ductal plate progenitors in fetal liver, cap mesenchimal cells in the developing kidney, fetal zone cells in adrenal glands, atrial and ventricular cardiomyocytes in the fetal heart, radial glial cells in the fetal cerebral cortex and skeletal muscle cell precursors showed the highest levels of WT1 immunoreactivity. Future studies will be needed to detect differences in the expression of WT1 in various organs at different gestational ages, in order to better evaluate the role of WT1 in cell proliferation and differentiation during intrauterine human development.

Reoxygenation of asphyxiated newborn piglets: administration of 100% oxygen causes significantly higher apoptosis in cortical neurons, as compared to 21%.

OBJECTIVE: Evaluation of neuronal changes in an animal experimental model of normocapnic hypoxia- reoxygenation. MATERIALS AND METHODS: Fifty male piglets were the study subjects; normocapnic hypoxia was induced in 40 piglets and ten were sham-operated (controls). When bradycardia and/or severe hypotension occurred, reoxygenation was initiated. Animals were allocated in 4 groups according to the oxygen concentration, they were resuscitated with 18%, 21%, 40%, and 100% O2. Persisting asystole despite 10 minutes of cardiopulmonary resuscitation and return of spontaneous circulation were the endpoints of the experiment. Surviving animals were euthanized and brain cortex samples were collected, hematoxylin and eosin-stained, and examined for apoptotic bodies observing 10 consecutive high power fields. RESULTS: Histological examination of the control group did not show any pathological change. On the contrary, apoptosis of neurons was found in 87.5% of treated animals. When specimens were examined according to the oxygen concentration used for resuscitation, we found marked intergroup variability; a higher percentage of apoptotic neurons was observed in piglets of group 4 (100% oxygen) compared to the others (P=0.001). CONCLUSIONS: This preliminary data shows that normocapnic hypoxia and reoxygenation in Landrace/Large White piglets resulted in significant histological changes in the brain cortex. The degree of pathological changes in cortical neurons was significantly associated with the oxygen concentration used for reoxygenation, with a higher percentage of apoptotic neurons being observed in piglets reoxygenated with 100% compared to 18% O2 and to 21% O2.

Perinatal heart programming: long-term consequences.

OBJECTIVE: evaluate the relationship between impaired growth during intrauterine life and adult risk of cardiovascular disease and death. MATERIALS: review of the most important contributions to the relationship between intrauterine fetal life and heart disease insurgence in childhood and adulthood, starting with a schematic representation of the principal steps in human heart development, discussion of the new theory on the relevance of the number of cardiomyocytes that every heart shows at birth. RESULTS: intrauterine environment defines the epigenetic profile of newborns, with implications for the risk of developing diseases later in adult life. This means that the programming of cardiovascular risk and other pathologies, such as obesity, in adulthood takes place starting from intrauterine life. CONCLUSIONS: it can be hypothesized that by preventing and eventually treating cardiovascular diseases in the pediatric age, if these are already present in their early and/or in light forms, the long-term management of complications could be approached differently and more effectively than by postponing the treatment to adulthood. The future challenge in this fascinating field of clinical research is the discovery of the molecular mechanisms underlying the association between intrauterine growth restriction and fetal onset of adult cardiac disease, so as to make a dream come true by applying primary prevention of adult heart disease in the womb.

Neonatal asphyxia and forensic medicine.

In the last decades, the scientific literature addressing neonatal encephalopathy has grown in a logarithmic way and malpractice claims in obstetrics and neonatology have become a major threat to the health service. At the moment, scientific evidence are insufficient to clearly identify in each single case whether the hypoxic insult has developed in the course of labor or in the first few hours after the birth or, otherwise, whether the damage has to recognize a remote and long-lasting cause acting during pregnancy. Several authors feel that this scientific uncertainty leads to a higher percentage of civil suit decisions prone to recognizing a guilty medical behavior, and they wish a more in-depth analysis of all these cases to clearly identify all the data either in favor or in contrary to the assumption of the existence of a causal correlation between neonatal encephalopathy and medical misbehavior. This article will focus on the medico-legal approach to a hypoxic-ischemic event in the perinatal period, addressing the relevant data to be collected in order to establish the medical and juridical cause of the neonatal damage.