Complexity and complicity in eclampsia: barriers or bridges?

Genesis of preeclampsia: an epidemiological approach

THERE ARE ANALYZED SOME OF THE MAIN ASPECTS RELATED TO THE CAUSALITY OF PREECLAMPSIA, PRIVILEGING TWO TYPES OF MODELS: the clinic model and the epidemiologic model, first one represented by the hypothesis of the reduced placental perfusion and the second one considering the epidemiologic findings related to the high levels of psychosocial stress and its association with preeclampsia. It is reasoned out the relevance of raising the causality of the disease from an interdisciplinary perspective, integrating the valuable information generated from both types, clinical and epidemiologic, and finally a tentative explanatory model of preeclampsia is proposed, the subclinical and sociocultural aspects that predispose and trigger the disease are emphasized making aspects to stand out: the importance of reduced placental perfusion as an indicator of individual risk, and the high levels of physiological stress, as a result of the unfavorable conditions of the psychosocial surroundings (indicator of population risk) of the pregnant women.

Non-Linear Analysis Approach of Maternal Heart Rate Patterns in Normal and Pre-Eclamptic Pregnancies

Identification of the pregnant woman prone to develop pre-eclampsia later during her course of the pregnancy is a clinical challenge in clinical obstetrics. A new and non-invasive approach to detect abnormalities in pre-eclamptic women that differentiate from women with uneventful pregnancies is presented here. We applied non-linear and fractal features for classifying the dynamical complexity of the heart rate (HR) patterns corresponding to seven normal subjects and eight pre-eclamptic patients. Significant differences in the estimated largest Lyapunov exponent and in the correlation dimension between normotensive women and those with pre-eclampsia were found, suggesting they may have potential as new markers for pre-eclampsia. HR patterns in healthy and pre-eclamptic pregnancies correspond to complex non-linear dynamics, which could arise from the contribution of stochastic and chaotic components. HR of pre-eclamptic patients also revealed a more regular dynamic behavior than those belonging to normal pregnancies, corroborating the general observation that diseased states may be associated with regular HR patterns.

Shed membrane fragment modulation of CD3-zeta during pregnancy: link with induction of apoptosis

Our objective was to identify shed placental plasma membrane fragments in the maternal circulation and determine whether these fragments are capable of down-regulating CD3-zeta chain expression and inducing apoptosis in T lymphocytes. Sera, isolated from the blood of pregnant women at 26-29 weeks gestation that subsequently had uncomplicated term deliveries, were subjected to high exclusion-limit gel chromatography to isolate placental membrane fragments. The placental origin of the fragments was confirmed by the presence of placental-type alkaline phosphates. These shed membrane fragments were further analyzed for the presence of Fas ligand (FasL) and modulation of CD3-zeta expression on cultured T-lymphocytes (Jurkat cells). The ability of the shed membrane fragments to induce apoptosis was assayed using a cell death ELISA. Components associated with Fas-dependent apoptosis (caspase-3, bcl-2 and bax) were characterized using western immunoblot following exposure to serum-derived membrane fragments. Placental membrane fragments were identified in all pregnancy sera, but not in non-pregnant controls. The 41 kDa FasL was identified in membrane fragment isolates and all samples were capable of inducing apoptosis as determined by the ELISA assay. Exposure of T lymphocytes to isolated membrane fragments suppressed the expression of CD3-zeta. The induction of apoptosis correlated with the induction and activation of caspase 3 and the induction of bax. Placenta-derived membrane fragments are detectable in the maternal circulation. These membrane fragment isolates are capable of inducing FasL-mediated apoptosis and down-regulating CD3-zeta expression, which may contribute to the immune tolerance of the fetus.