Cell Free Expression of hif1α and p21 in Maternal Peripheral Blood as a Marker for Preeclampsia and Fetal Growth Restriction

Preeclampsia, a severe unpredictable complication of pregnancy, occurs in 6% of pregnancies, usually in the second or third trimester. The specific etiology of preeclampsia remains unclear, although the pathophysiological hallmark of this condition appears to be an inadequate blood supply to the placenta. As a result of the impaired placental blood flow, intrauterine growth restriction (IUGR) and consequential fetal oxidative stress may occur. Consistent with this view, pregnancies complicated by preeclampsia and IUGR are characterized by up-regulation of key transcriptional regulators of the hypoxic response including, hif1α and as well as p53 and its target genes. Recently, the presence of circulating cell-free fetal RNA has been documented in maternal plasma. We speculated that pregnancies complicated by preeclampsia and IUGR, will be associated with an abnormal expression of p53 and/or hif1α related genes in the maternal plasma. Maternal plasma from 113 singleton pregnancies (72 normal and 41 complicated pregnancies) and 19 twins (9 normal and 10 complicated pregnancies) were collected and cell free RNA was extracted. The expression of 18 genes was measured by one step real-time RT-PCR and was analyzed for prevalence of positive/negative expression levels. Results indicate that, among the genes examined, cell free plasma expressions of p21 and hif1α were more prevalent in pregnancies complicated by hypoxia and/or IUGR (p<0.001). To conclude, we present in this manuscript data to support the association between two possible surrogate markers of hypoxia and common complications of pregnancy. More work is needed in order to implement these findings in clinical practice

Variation of interspecific interactions at different ecological levels within an assemblage of Arctic marine predators

International audienceHow interspecific interactions change across scales is poorly known. Such knowledge might help us understand how species interact within communities and highlight scale-dependent ecological processes in play among species. Here, I propose to analyze the inter-annual variation of a species assemblage at different ecological levels. For this, I joined a two-stage modeling approach and a spatially explicit multivariate model to analyze the interspecies relationships among six species of pelagic seabirds from 2004 to 2015 in the Barents Sea. The large-scale (~400 km) pattern of interactions revealed by the analyses suggests a change in the composition of the seabird community along the climatic gradient from south to north. At medium-scale (~300 km), the community was split into two areas (i.e., Arctic and sub-Arctic areas) suggesting niche differentiation of Arctic and sub-Arctic species driven by resource partitioning and interference competition. At a small-scale (~40 km), species with different body sizes were positively associated suggesting facilitation for accessing food although the species with the smallest body size was negatively associated with the species involved in the facilitation process suggesting interspecific interference competition. Over the years, the large-scale patterns were persistent, suggesting niche establishment, while small-scale patterns were highly variable suggesting only ephemeral interactions among species. My study demonstrates that interspecific relationships are scale-dependent and play major roles in structuring community. Untangling how species are associated with different ecological levels over time is indispensable to better understand how community structure contributes to ecological system dynamics