Donald W. Morrish

Functional regulation of human trophoblast differentiation

The human trophoblast differentiates from proximal cell column cytotrophoblasts into two lineages: a villous phenotype that results in cell fusion and formation of syncytium and an extravillous phenotype that adopts an invasive behavior and displays cell surface markers of an endothelial cell. Both phenotypes develop spontaneously in in vitro cultured cytotrophoblasts, but there is a clear gestational regulation by unknown genetic and/or maternal environmental factors that results in first trimester villous cytotrophoblasts entering the invasive pathway and term villous cytotrophoblasts entering the syncytial pathway. No genetic factors are known that induce the invasive pathway. First trimester cytotrophoblasts are induced to enter the invasive pathway by activin A, LIF and IL-1beta but inhibited from differentiating in this direction by TGFbeta1, TGFbeta3, glucocorticoids and hypoxia. Term villous cytotrophoblasts are stimulated by EGF, EGF-II, IGFBP-1, alpha1beta1 integrin (laminin receptor) and hypoxia. Term villous cytotrophoblasts are stimulated to form a syncytium by EGF, GM-CSF, CSF-1, dexamethasone, hCG, fibronectin, collagen I and PL48 and inhibited by TGFbeta1. As well, there is evidence that TNFalpha and interferon gamma induce and EGF inhibits apoptosis. This provides a mechanism for trophoblast turnover and renewal. Further research will be likely to uncover additional genetic, cytokine, extracellular matrix and physicochemical factors that regulate this complex process.

In vitro cultured human term cytotrophoblast: A model for normal primary epithelial cells demonstrating a spontaneous differentiation programme that requires EGF for extensive development of syncytium

Normal human term cytotrophoblast cells prepared by trypsin-DNAse I digestion with and without secondary immunological purification with CD9 antibodies were investigated for the expression of morphological and genetic markers of proliferation and differentiation. After 24 h of culture, the cell preparations demonstrated spontaneous formation of microvilli and formation of small syncytial units as assessed by desmoplakin staining and FITC-dextran microinjection. EGF was required for mature syncytial formation. Compared to log-phase proliferating HeLa cells, uptake of [3H]thymidine incorporation was low and quickly decreased to negligible levels. Expression of the proto-oncogenes c-myc, c-fos, and c-jun and histone 2A decreased rapidly in the first 24 h of culture in both cell preparations, followed by an increase in expression of c-fos and junB over the next 3 days of culture. Proto-oncogene changes were similar in attached and suspension cells. Spontaneous increases in alpha hCG, pregnancy-specific beta(1)-glycoprotein and 3 beta-hydroxysteroid dehydrogenase (3 beta OHSD) occurred within 1 day in both cell preparations. EGF receptor blocking antibodies did not inhibit minor degrees of spontaneous syncytial formation nor inhibit spontaneous expression of alpha hCG or 3 beta OHSD mRNA, but did prevent extensive synctialization induced by EGF. The results demonstrate that term cytotrophoblast cells even in serum-free conditions or suspension culture rapidly commit to a non-proliferative differentiation program in culture which includes limited syncytialization and marked hormone mRNA expression. However, EGF is required for extensive syncytial development.

Functional, long-term cultures of human term trophoblasts purified by column-elimination of CD9 expressing cells.

We have extended previous observations of expression of the trypsin-resistant cell surface antigen CD9 on placental fibroblasts to virtually all cells in the villous stroma and developed a method for eliminating CD9 expressing cells from trypsinized placental preparations. Preparations incubated with the mouse anti-human CD9 monoclonal antibody 50H.19 were passed through a goat anti-mouse immunoglobulin column that captures CD9 expressing cells. Approximately 95 per cent of the eluted cells stained positive with the villous trophoblast specific antibody GB25 and could be cryopreserved and thawed with > 80 per cent recovery in culture. One week cultures contained fewer than 0.3 per cent vimentin positive (mesenchymal) cells and maintained secretion of hCG. Two week cultures remained free of fibroblasts and macrophages. Clusters of trophoblasts that formed spontaneously during the first week of culture were shown by microinjection of carboxyfluorescein and by staining with anti-desmoplakin antibody to be a patchwork of mononuclear cells and syncytial units. Although the DNA content of the culture decreased by 35 per cent during the 2 week culture, the metabolic capacity and protein content remained relatively constant. Thus, CD9 immuno-elimination gives a high yield of enriched and viable trophoblasts that can be cultured for at least 2 weeks with almost no contamination by stromal cells.

Identification by subtractive hybridization of a spectrum of novel and unexpected genes associated with in vitro differentiation of human cytotrophoblast cells.

We have previously demonstrated that epidermal growth factor (EGF), colony stimulating factor-1 (CSF-I), and granulocyte-monocyte colony stimulating factor (GMCSF) stimulate, while transforming growth factor beta 1 (TGF beta 1) inhibits, cytotrophoblast differentiation. To identify genes mediating EGF induced differentiation, we constructed a subtracted cDNA library between undifferentiated cytotrophoblast and differentiating cytotrophoblast. We identified six novel genes and four known syncytial products alpha-human chorionic gonadotrophin (alpha hCG) pregnancy-specific beta 1-glycoprotein, 3 beta-hydroxysteroid dehydrogenase, and plasminogen activator inhibitor type 1 whose mRNAs increased during differentiation. Ten other genes were identified whose mRNAs increased during differentiation. Five of these (keratin 19, calcreticulin, heat shock protein 27, serum and glucocorticoid-regulated kinase and adrenomedullin) were not previously reported to be expressed in placenta. Five other genes known to be expressed in placenta were identified. keratin 8, fibronectin, mitochondrial ATP synthase, 1119, and cytosolic copper-zinc superoxide dismutase (SOD-1). Several of these genes may have regulatory functions in trophoblast differentiation.

Osteoporosis Case Manager for Patients With Hip Fractures: Results of a Cost-effectiveness Analysis Conducted Alongside a Randomized Trial

BACKGROUND In a randomized trial of patients with hip fractures, we previously demonstrated that a hospital-based case manager could increase rates of appropriate osteoporosis treatment to 51% compared with 22% for usual care (P < .001). Alongside that trial, we conducted an economic analysis. METHODS Patients with hip fractures were randomized to usual care (n = 110) or a case manager (n = 110) and followed up for 1 year. Time-motion studies were used to determine intervention costs. From a third-party health care payer perspective and over the patients remaining lifetime, a Markov decision-analytic model was constructed to determine cost-effectiveness of the intervention compared with usual care. Costs and benefits were discounted at 3% and expressed in 2006 Canadian dollars. RESULTS The intervention cost CaD

Demonstration of specific secretory granules for human chorionic gonadotropin in placenta

56 per patient. Compared with usual care, the intervention strategy was dominant: for every 100 patients case managed, 6 fractures (4 hip fractures) were prevented, 4 quality-adjusted life-years were gained, and CaD

Effect of Adrenomedullin on Placental Arteries in Normal and Preeclamptic Pregnancies

260 000 was saved by the health care system. Irrespective of the number of patients case managed, the intervention reached a break-even threshold within 2 years. The intervention dominated usual care over the entire spectrum of 1-way sensitivity analyses and was cost-saving in 82% of probabilistic model simulations. CONCLUSIONS Compared with usual care, we found that using a case manager for patients with hip fractures increased rates of appropriate osteoporosis treatment. The intervention dominated usual care, and the analysis suggests that systems implementing an intervention similar to ours should expect to see a reduction in fractures, gains in life expectancy, and substantial cost savings. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00175175.

PREPARATION OF FIBROBLAST-FREE CYTOTROPHOBLAST CULTURES UTILIZING DIFFERENTIAL EXPRESSION OF THE CD9 ANTIGEN

Existence of secretory granules and exocytosis during secretion of human chorionic gonadotropin (hCG) in human placenta has been a point of controversy. Using two methods, the highly sensitive avidin-biotin complex (ABC) method and the protein A-gold technique, for immunochemical identification of beta-hCG on electron microscopic sections, we have examined placentas at 8-10 weeks gestation and at term for the presence of secretory granules. First-trimester placentas demonstrated plentiful syncytiotrophoblast cytoplasmic granules, some undergoing exocytosis, when stained using specific beta-hCG antiserum in the ABC and protein A-gold methods. Term placentas did not show positive reaction product. The data demonstrate that the classic secretory granule-exocytosis pathway mediates placental hCG secretion. However, clear morphological differences exist between placenta granules and hormone secretory granules observed in pituitary, consistent with known functional differences between these organs. This methodology will be useful for further studies of the secretory pathways for placental peptides.

Differential proteomic analysis of highly purified placental cytotrophoblasts in pre-eclampsia demonstrates a state of increased oxidative stress and reduced cytotrophoblast antioxidant defense.

Adrenomedullin is a potent vasodilatory peptide with plasma levels that increase during pregnancy. Although fetoplacental adrenomedullin levels are reported to increase in preeclampsia, maternal plasma levels may be elevated or decreased, or they may resemble those in normal pregnancy. In other hypertensive conditions, adrenomedullin increases. Therefore, we hypothesized that maternal plasma adrenomedullin levels would be higher in hypertensive pregnancies than in normotensive pregnancies and that the higher placental resistance found in preeclamptic pregnancies results from blunted activity of adrenomedullin on the vasculature. Adrenomedullin concentrations in plasma from women with normotensive pregnancies, gestational hypertension, and preeclampsia were determined by radioimmunoassay. Stem villous arteries from normotensive and preeclamptic pregnancies were dissected and mounted on a wire myograph system. Arteries were first preconstricted to 80% of their maximum constriction with U46619, a thromboxane A2 mimetic, and exposed to cumulative doses of adrenomedullin (1×10−9 to 3×10−7 mol/L). Contrary to our hypothesis, there were no significant differences in maternal plasma adrenomedullin levels among patients with normal pregnancies, gestational hypertension, and preeclampsia. Adrenomedullin significantly relaxed arteries from both normal and preeclamptic placentas, but there was no significant difference between the 2 groups. During normal pregnancy, adrenomedullin may contribute to the low placental vascular resistance. This pathway appears to be intact in preeclampsia. We conclude that the increased placental vascular resistance observed in preeclampsia is due neither to reduced adrenomedullin secretion nor to an attenuated vascular responsiveness. Moreover, unlike other hypertensive disorders, there is no compensatory rise in circulating adrenomedullin levels.

Facilitated bone mineral density testing versus hospital‐based case management to improve osteoporosis treatment for hip fracture patients: Additional results from a randomized trial

SummaryThe leukemia-associated antigen CD9 is present on a variety of normal cells, with apparent variable expression on normal human fibroblasts. In this study, we demonstrate by immunoperoxidase staining and direct binding studies that the CD9 antigen is uniformly expressed on normal human fibroblasts grown from first trimester and term placenta, embryonic fetal fibroblasts, and from human adult and fetal skin fibroblasts. Higher CD9 expression was present on fetal cells. CD9 antigen was not present on trophoblast. Over 99% of fibroblasts could be absorbed onto antibody to the CD9 antigen conjugated to magnetic beads. By applying this selective immunoadsorption of fibroblasts to term placental cytotrophoblast preparations, we demonstrated that fibroblast contamination could be nearly completely eliminated. This is a novel technique for purifying primary trophoblast cultures and may have wider applicability in cell culture of other cell types.