RESUMO
Follow-up studies have shown that the vast majority of neurological abnormalities present during childhood can have a prenatal or perinatal origin. It is relevant, therefore, to investigate the timing of adverse insults in the search for measures of prevention. However, such knowledge is still incomplete and subject to debate. Until recently, clinical-laboratory assessment was based essentially on biochemical aspecific parameters, ultrasound and Doppler patterns, and the determination of blood pH and gases. However, the measurement of brain constituents may offer a direct indicator of cell damage in the nervous system. The S100 B protein, a calcium-binding protein highly concentrated in the nervous system, appears to meet the criteria required of such a marker in prenatal and perinatal medicine for its reproducible, simple and sensible measurements. The aim of this study was to determine whether S100B protein could be helpful in the detection of brain distress in intrauterine growth-retarded [IUGR] fetuses, we studied, by a case-control study, the correlation between S100B protein and the degree of fetoplacental blood flow impairment. Maternal and umbilical blood samples were collected at delivery from IUGR pregnancies with normal [n=10] or abnormal [n=10] umbilical artery Doppler findings and from 20 uncomplicated pregnancies. S1020B protein levels were measured by means of a specific RIA and flow velocimetry waveforms were recorded from uterine, umbilical, and fetal middle cerebral arteries. The results showed that maternal plasma S100B protein levels were under the limit of detection in both IUGR and control groups. In contrast, fetal S100B protein levels in umbilical plasma were significantly higher [p=0.04] in IUGR patients [123.5 +/- 69.7 fmol/mL] compared to the controls [52.4 +/- 20.2 fmol/mL]. IUGR fetuses with redistribution of blood flow showed the higher concentration of the protein [164.8 +/- 54.9 fmol/mL]. Fetal S100B protein levels correlated negatively with middle cerebral artery pulsatility index [r=-0.528; p=0.02], and positively with umbilical artery pulsatility index to middle cerebral artery pulsatility index ratio [r = 0.489; p=0.03]. In the control group, a negative significant correlation between S100B protein and gestational age was found [r= 0.76; p=0.01]. Circulating S100B protein is increased in IUGR fetuses and correlates with cerebral hemodynamics, suggesting that it may represent an index of cerebral cell damage in the perinatal period