Expression Of S100b, NSE And GFAP In The Placenta And Umbilical Cord Of Different Gestational Ages

ObjectivePresently, S100b and NSE and GFAP are the most common markers of hypoxic-ischemic brain injury .NSE is located in the neurons.S100b and GFAP are present in astrocytes .In perinatology, the significance of neuronal markers such as S100b and NSE in amniotic fluid, cord blood, neonatal blood, and neonatal cerebrospinal fluid has been investigated to predict brain damage in the newborn especially after perinatal asphyxia and preterm labor. However, the expression of S100b and NSE in umbilical cord and placental tissue has been found according to some foreigh studys. Therefore the question arises whether the immunoreactivity of S100b and NSE in (cord) blood and amniotic fluids, indicates exclusively damage in brain tissue or may also result from protein release from placental or umbilical cord tissue. The aim of this study was to investigate the localization and immunoreactivity of S100b and NSE and GFAP systematically in placental and umbilical cord tissue and to make sure if they are suitable markers for perinatal brain damage.Materials and Methods1. AgentThe monoclonal antibodies to S100b and NSE and GFAP ,as well as immuno-histochemistry kit are provided by Maixin Biotechnology Company.2. MaterialsPlacental and umbilical cord tissues were obtained from 30 healthy pregnant women at different gestational ages. Tissues were collected below 28 weeks' gestation from ten women who underwent elective abortion for fetal or maternal indications, between 28 and 36 weeks' gestation from ten women after preterm delivery, and above 36 weeks' gestation from ten women after spontaneous delivery. Patients with multiple gestation, fetal cerebral malformations, Down syndrome, or infections were excluded from the study. Immediately after delivery, biopsies were taken from the pericentral area of the placenta. Samples from the umbilical cord were taken near the fetus. Tissue was fixed in 10%paraformaldehyde.3. MethodsThe localization and immunoreactivity of S100b and NSE and GFAP are detected by SP immunohistochemistry. Positive comparison film served as a positive control and sections with PBS instead of primary antibody as a negative control.4. Results assessmentThe proportion of positive cells was counted in six randomly selected fields in per section. The average values were used for the total immunohistochemic counts.5. Statistical treatmentAll the results are expressed by means value±standard error (x|-±s) . Comparison of positive cell at different developmental stages was made by one-way analysis of variance followed by Turkey test. Statistical significance was set at P < 0.05.Results1. In the placenta, S100b was localized in trophoblast cells, myofibroblasts, smooth muscle cells of the vascular wall, and macrophages. The intensity of immunostaining of S100b increased with advancing gestation. In the umbilical cord , S100b was present in endothelial cells of umbilical vessels, the smooth muscle cells of the vascular wall, myofibroblasts, amnion epithelium, macrophages, and monocytes. No significant difference was found at different gestational ages2. In the placenta, NSE immunoreactivity was found in trophoblast cells, myofibroblasts, smooth muscle cells of the vascular wall, and macrophages. In the umbilical cord , NSE was localized in endothelial cells of umbilical vessels, the smooth muscle cells of the vascular wall, myofibroblasts, amnion epithelium, macrophages, and monocytes. There was no apparent change in the amount of immunoreactive NSE present in the placenta and umbilical cord at different gestational ages3. Glial fibrillary acidic protein showed no immunoreactivity in the placenta and umbilical cord of all 30 cases.ConclusionThis study demonstrated that fetoplacental tissues contain S100b and NSE, suggesting that these tissues may, at least in part, be responsible for the high level found in the fetal circulation. Although the significance of placental S100b and NSE is unknown, this origin should be taken into account when this protein is used as a marker of brain injury in the fetus or infant at birth. However, GFAP showed no immunoreactivity in the umbilical cord and the placenta .So GFAP has better brain specificity . Brain-restricted proteins such as glial fibrillary acidic protein seems more promising as a marker of brain injury.