Isolation and Characterization of Human Trophoblast Side-Population (SP) Cells in Primary Villous Cytotrophoblasts and HTR-8/SVneo Cell Line

Recently, numerous studies have identified that immature cell populations including stem cells and progenitor cells can be found among “side-population” (SP) cells. Although SP cells isolated from some adult tissues have been reported elsewhere, isolation and characterization of human trophoblast SP remained to be reported. In this study, HTR-8/SVneo cells and human primary villous cytotrophoblasts (vCTBs) were stained with Hoechst 33342 and SP and non-SP (NSP) fractions were isolated using a cell sorter. A small population of SP cells was identified in HTR-8/SVneo cells and in vCTBs. SP cells expressed several vCTB-specific markers and failed to express syncytiotrophoblast (STB) or extravillous cytotrophopblast (EVT)-specific differentiation markers. SP cells formed colonies and proliferated on mouse embryonic fibroblast (MEF) feeder cells or in MEF conditioned medium supplemented with heparin/FGF2, and they also showed long-term repopulating property. SP cells could differentiate into both STB and EVT cell lineages and expressed several differentiation markers. Microarray analysis revealed that IL7R and IL1R2 were exclusively expressed in SP cells and not in NSP cells. vCTB cells sorted as positive for both IL7R and IL1R2 failed to express trophoblast differentiation markers and spontaneously differentiated into both STB and EVT in basal medium. These features shown by the SP cells suggested that IL7R and IL1R2 are available as markers to detect the SP cells and that vCTB progenitor cells and trophoblast stem cells were involved in the SP cell population

Capillary Remodeling in Infants Born to Hypertensive Pregnancy: Pilot Study

BACKGROUND Capillary rarefaction is pathognonnonic of essential hypertension. We have previously shown significant capillary rarefaction in normotensive adult offspring of hypertensive parents, suggesting a familial predisposition in which capillary rarefaction represents a primary vascular abnormality that antedates the onset of sustained elevation of blood pressure (BP). We have recently reported that low-birth weight (LBW) infants, born at term or preterm, to normotensive mothers do not have capillary rarefaction at birth. We hypothesized that infants born to mothers with hypertensive disorders of pregnancy (HDP) would have significant capillary rarefaction at birth when compared to infants of normotensive mothers. METHODS We studied 22 infants born to hypertensive mothers and compared them to 40 normal birth weight infants born at term to normotensive mothers. We used orthogonal polarized spectroscopy to measure basal (i.e., functional) and maximal (i.e., structural) skin capillary densities according to a well-validated protocol. RESULTS We found that term infants born to hypertensive mothers had significantly lower maximal capillary density (MCD) (mean difference of -5.0 capillaries/mm(2); P < 0.05). However, preterm infants with LBW born to hypertensive mothers tended to have higher basal and maximal skin capillary densities compared with term infants. CONCLUSIONS While the results in term infants are consistent with our belief that capillary rarefaction in essential hypertension is likely to be a primary vascular abnormality, the results in preterm infants may suggest that the intrauterine environment may exert some influences on the remodeling of the microcirculation which may delay the onset of capillary rarefaction in these infants