Soluble P-selectin levels during normal pregnancy: a longitudinal study.

Objective To investigate soluble P-selectin (sP-selectin) levels and platelet parameters in normal pregnant women compared with non-pregnant control subjects. Design A longitudinal case–control study. Setting Obstetric outpatient clinic in the Jubilee Maternity Hospital, Belfast. Population One hundred and twenty normal pregnant women and 41 non-pregnant age-matched control subjects. Methods The plasma concentration of sP-selectin in pregnant women sampled at 12, 20 and 35 weeks of gestation, and, in a subgroup at three days postpartum, and non-pregnant controls sampled in parallel, was determined using a commercial quantitative sandwich immunoassay kit. Platelet parameters on each blood sample were also recorded using a SYSMEX SE 9500 analyser. Main outcome measures Plasma sP-selectin as a measure of platelet activation in normal pregnancy. Results Soluble P-selectin was significantly higher in pregnant women than in non-pregnant control subjects at 20 and 35 weeks of gestation, (P < 0.01, and P < 0.001, respectively). Correlation analyses showed positive correlation between sP-selectin and platelet count in pregnant women at 20 and 35 weeks of gestation (r = 0.247, P < 0.05 and r = 0.360, P < 0.001, respectively). Soluble P-selectin concentration per platelet was also significantly higher in pregnant women than in non-pregnant control subjects at 20 and 35 weeks of gestation (P < 0.001). Conclusions Our results show that sP-selectin concentration is significantly higher in the second and third trimester of pregnancy when compared with non-pregnant control subjects sampled in parallel. This finding clarifies previous conflicting results on platelet activation in normal pregnancy, and is in agreement with those earlier studies which reported, using other methods, increased platelet activation in normal pregnancy

A multi-gene transcriptional profiling approach to the discovery of cell signature markers

A profile of transcript abundances from multiple genes constitutes a molecular signature if the expression pattern is unique to one cell type. Here we measure mRNA copy numbers per cell by normalizing per million copies of 18S rRNA and identify 6 genes (TIE1, KDR, CDH5, TIE2, EFNA1 and MYO5C) out of 79 genes tested as excellent molecular signature markers for endothelial cells (ECs) in vitro. The selected genes are uniformly expressed in ECs of 4 different origins but weakly or not expressed in 4 non-EC cell lines. A multi-gene transcriptional profile of these 6 genes clearly distinguishes ECs from non-ECs in vitro. We conclude that (i) a profile of mRNA copy numbers per cell from a well-chosen multi-gene panel can act as a sensitive and accurate cell type signature marker, and (ii) the method described here can be applied to in vivo cell fingerprinting and molecular diagnosis