Bruno M. Polliotti

Second-trimester maternal serum placental growth factor and vascular endothelial growth factor for predicting severe, early-onset preeclampsia.

OBJECTIVE To determine whether alterations in second-trimester maternal serum cytokine concentrations can identify women at risk for developing severe, early-onset preeclampsia. METHODS Patients with severe preeclampsia requiring delivery prior to 34 weeks (n = 20) were each matched by gestational age, gravidity, parity, and sample freezing time with three healthy controls who delivered at term (n = 60). By using second-trimester maternal sera originally collected for fetal aneuploidy screening, the concentrations of placental growth factor, vascular endothelial growth factor, granulocyte colony-stimulating factor, endothelin-1, and human chorionic gonadotropin were compared between patients and controls. Logistic regression analysis was used to estimate odds ratios for high versus low (median split) cytokine concentrations with respect to the development of severe, early-onset preeclampsia. Receiver operating characteristic (ROC) curves based on a second logistic regression, using actual cytokine values, were plotted to illustrate reciprocal impact on sensitivity and specificity. RESULTS Placental growth factor and vascular endothelial growth factor levels were significantly lower in patients than in controls. No significant differences were observed for the other cytokines. The odds ratios (with 95% confidence intervals) were 15.54 (3.29, 73.40) for vascular endothelial growth factor and 4.20 (1.35, 13.06) for placental growth factor. Receiver operating characteristic analysis of placental growth factor and vascular endothelial growth factor confirmed that both were useful in discriminating between patients and controls. Models combining both vascular endothelial growth factor and placental growth factor provided the best performance for identifying patients at risk for developing severe, early-onset preeclampsia, according to both odds ratios and ROC analyses. CONCLUSION Combined analysis of placental growth factor and vascular endothelial growth factor is potentially useful as a tool for early identification of patients at risk for developing severe, early-onset preeclampsia.

Marginal Transfer of ReoPro™ (Abciximab) Compared with Immunoglobulin G (F105), Inulin and Water in the Perfused Human Placenta In Vitro

ReoPro (Abciximab), a Fab fragment of a human-murine chimeric monoclonal antibody, binds to glycoprotein IIb/IIIa receptors on human platelets and inhibits platelet aggregation. Can ReoPro transit the human placenta since it does not have an Fc (domain) as does IgG? This question was addressed using an in vitro term human placental lobular dual perfusion model. ReoPro, along with 3H(2)O, inulin or 125I-F105 human IgG(1), were added to the maternal reservoir for 6 or >12 h, ReoPro was equivalent to, or exceeded, clinically relevant plasma concentrations (0.3-3 microg/ml). 3H(2)O rapidly appeared in the fetal circuit, while fetal 14C-inulin never equilibrated with the maternal inulin. After 6 h, 125I-F105 was present with fetal/maternal percentages-0.55 per cent. ReoPro was not detectable (<3.9 ng/ml) in the fetal circuit during or at the end of any perfusion. Using immunohistochemistry, ReoPro was only detected attached to maternal and fetal platelets, and to the trophoblastic surface of the placental villi. Only pharmaceutically insignificant amounts of ReoPro were detected in the fetal circuit, which demonstrates a barrier capacity of the human term placenta for this Fab fragment compared with IgG.

Human immunodeficiency virus infection: In situ polymerase chain reaction localization in human placentas after in utero and in vitro infection

OBJECTIVE We compared localization of human immunodeficiency virus type 1 within human placentas infected in utero with localization within human placental explants infected in vitro. STUDY DESIGN Placental tissues from 3 cases of vertical transmission of human immunodeficiency virus type 1 were studied. Human placental explants from 6 term pregnancies not complicated by human immunodeficiency virus type 1 infection were infected in vitro with human immunodeficiency virus type 1(Ba-L). Sections from each placental explant and each placenta infected in utero were analyzed for human immunodeficiency virus type 1 localization by means of in situ polymerase chain reaction. RESULTS Human immunodeficiency virus type 1 was primarily localized within syncytiotrophoblast, Hofbauer cells, and extravillous mononuclear cells in placental tissue sections from cases of in utero infection. Within placental explants human immunodeficiency virus type 1 deoxyribonucleic acid was found in syncytiotrophoblast and Hofbauer cells. The distributions of viral localization were similar in placentas infected in utero and placental explants infected in vitro. CONCLUSION Human immunodeficiency virus type 1 can be localized to specific human placental cells (eg, syncytiotrophoblast) after either in utero or in vitro infection, which demonstrates the specificity and selectivity of human immunodeficiency virus infection in the human placenta.

Production of granulocyte colony-stimulating factor by the human placenta at various stages of development

The human placenta is capable of producing a variety of haematopoietic growth factors in vitro. It is not clear, however, whether the placenta produces such factors in vivo and if so, whether placental production of haematopoietic growth factors has a physiological role in fetal haematopoietic development. As a step toward making this determination, we assessed whether the onset of placental production of granulocyte colony-stimulating factor (G-CSF), in vivo, coincides with the onset of granulocytopoiesis in the developing fetus. To make this assessment, we obtained human placentae between 10 weeks of gestation and term and studied production of G-CSF in several ways. First, we sought to determine whether the onset of production of G-CSF mRNA in the placenta immediately precedes the appearance of neutrophil development in the fetus. Second, we assessed the effect of gestational age on the capacity of the placenta to generate G-CSF in vitro, by incubating cubes of placenta, with or without including interleukin-1 alpha (IL-1 alpha) in the culture media, and quantifying G-CSF in the cell culture supernatants 24 h later. Third, we assessed the rate of G-CSF production by the placenta, by perfusing two normal, term placentae using a membrane-oxygenator system, and quantifying G-CSF, at intervals, in the perfusates. We found: (1) no evidence that placental production of G-CSF is involved in regulating granulocytopoiesis in the fetus, (2) that the healthy placenta contains little or no G-CSF mRNA in vivo, (3) the placenta at term has a far greater capacity to produce G-CSF, when stimulated, than does the placenta before term, and (4) that although the placenta does not normally produce G-CSF in vivo, it has the capacity of generating very large quantities of G-CSF continuously over at least several days.

HIV-1 INFECTION OF HUMAN PLACENTAL VILLOUS TISSUE IN VITRO

Summary The role of the placenta in the materno-fetal transmission of HIV-1 infection remains unexplained despite continuing progress. Among the many different experimental models (animal, isolated cells, placental tissue and isolated placental perfusion), we have selected human placental villous tissue culture as the one closest to the in utero condition associated with HIV infectivity and allowing experimentation for an adequate period of time The aim of this study was to investigate infectivity of several HIV-1 strains in human placental explants. Two laboratory strains, Ba-L and IIIB, and VI-5 (isolated from an HIV-positive baby) were utilized. Ba-L and VI-5 were Non-Syncytium-Inducing (NSI), and IIIB was Syncytium-Inducing (SI). Placental explants (first trimester and full term) were incubated for 24 hours with free virus of each strain, then intensively rinsed to remove the inoculum. After an additional five days of culture, explants were examined for infection by detection of p24 in the culture medium and by PCR amplification of viral DNA using two pairs of gag gene primers. Ba-L and VI-5 (NSI) infected both first and third trimester placental tissue. Positive indications of viral infection included increasing p24 production during the third day post-inoculation, which remained sustained for three days; and positive DNA-PCR detection in explants on day 6. As a control for infectivity, p24 increases could be completely abolished using HIV-Ig. Strain IIIB (SI) did not infect placental tissue as determined by lack of p24 release and absence of viral DNA by PCR detection. Free HIV-1 could infect the intact human placental villus and, as observed in vivo , NSI HIV-1 strains appeared more successful in infecting in vitro human placental tissue of first and third trimesters.

In situ PCR discriminates between infected and uninfected human placental explants after in vitro exposure to HIV-1

Summary Reliable identification of HIV-1 infection in the human placenta has been limited by inadequate sensitivity or specificity of available techniques. In situ PCR technology has been demonstrated to reliably detect HIV-1 infection in a variety of tissues. Experience with ISPCR in placentae is limited. The aim of this study was to evaluate the utility of ISPCR in detecting HIV-1 infection in placental explants exposed to free virus. Two viral strains, HIV IIIB and HIV Ba-L, were used. First and third trimester placental explants were exposed for 24 hours and then cultured in virus free media for an additional 4 days. Infectivity was assessed by detection of p24 and standard PCR. Tissue sections were also analyzed by ISPCR for infection. First and third trimester tissues exposed to HIV Ba-L were infected according to the p24 and PCR assays. Infected syncytiotrophoblast, Hofbauer cells and stromal cells were identified with ISPCR in these tissues. In contrast, neither the first nor the third trimester tissues are infected after exposure to HIV IIIB according to p24 or PCR assays. The HIV IIIB tissues were uninfected according to ISPCR analysis as well. Results of ISPCR and standard assays for infectivity correlated consistently for infected and uninfected tissues. Thus, ISPCR is a reliable tool in assessing HIV-1 infectivity of placentae. These data support the clinical observation that differences in infectivity of the conceptus is at least partially dependent upon the viral strain.

Free vitamin B12 and transcobalamin II-vitamin B12 complex uptake by the visceral yolk sac of the sprague-dawley rat : Effect of inhibitors

Exogenous free vitamin B12 or B12 bound to human transcobalamin II (TCII) accumulated in the near-term rat visceral yolk sac. The rates of their uptakes in vitro and in vivo increased rapidly with time then reached a plateau, which supports a saturable transport/binding process as the rate-limiting step for the uptake of free and TCII complexed B12. Both uptakes were significantly decreased by trypan blue, colchicine, and low temperature but not by ouabain. Such inhibition suggests that the absorption of free and bound B12 is via an endocytosis process dependent upon energy but not the magnesium-dependent sodium/potassium-activated ATPase. Thus, the role of the visceral yolk sac in vitamin transfer to the conceptus and the alterations in yolk sac function associated with birth defects and diminished growth can be integrally related.

THE ROLE OF THE PLACENTA IN THE VERTICAL TRANSMISSION OF HIV AND OTHER INFECTIOUS AGENTS - A Workshop Report -

Summary It was obvious to all in attendance that the dialogue concerning not only HIV but all infectious agents must be continued as part of these international placental conferences. It was noted with pleasure that significant advances have occurred since the meeting of the Rochester Trophoblast Conference in 1992. Enhanced efforts by not only placentologists but also microbiologists, molecular biologists, pathologists, obstetricians, neonatologists, pharmacologists and those in related disciplines continue to be required for the anticipated breakthroughs necessary for the prevention of the vertical transmission of serious infections in the newborn such as HIV. All of the presentations emphasized the essential role of the placenta in modulating the infectivity of the conceptus. It was concluded that placentae from all stages of gestation are at risk of infection by certain viral strains which appear to specifically infect the placenta, e.g., HIV.

Granulocyte Colony-Stimulating Factor and its Receptor at the Maternal-Fetal Interface: Localization, maternal to fetal transfer of G-CSF, and the physiologic role of G-CSF during normal gestation and intra-amniotic infection.† 1306

Granulocyte Colony-Stimulating Factor and its Receptor at the Maternal-Fetal Interface: Localization, maternal to fetal transfer of G-CSF, and the physiologic role of G-CSF during normal gestation and intra-amniotic infection.† 1306

PRODUCTION OF GRANULOCYTE COLONY-STIMULATING FACTOR BY THE HUMAN PLACENTA AT VARIOUS STAGES OF DEVELOPMENT. |[utrif]| 398

The human placenta is capable of producing a variety of haematopoietic growth factors in vitro. It is not clear, however, whether the placenta produces such factors in vivo and if so, whether placental production of haematopoietic growth factors has a physiological role in fetal haematopoietic development. As a step toward making this determination, we assessed whether the onset of placental production of granulocyte colony-stimulating factor (G-CSF), in vivo, coincides with the onset of granulocytopoiesis in the developing fetus. To make this assessment, we obtained human placentae between 10 weeks of gestation and term and studied production of G-CSF in several ways. First, we sought to determine whether the onset of production of G-CSF mRNA in the placenta immediately precedes the appearance of neutrophil development in the fetus. Second, we assessed the effect of gestational age on the capacity of the placenta to generate G-CSF in vitro, by incubating cubes of placenta, with or without including interleukin-1 alpha (IL-1 alpha) in the culture media, and quantifying G-CSF in the cell culture supernatants 24 h later. Third, we assessed the rate of G-CSF production by the placenta, by perfusing two normal, term placentae using a membrane-oxygenator system, and quantifying G-CSF, at intervals, in the perfusates. We found: (1) no evidence that placental production of G-CSF is involved in regulating granulocytopoiesis in the fetus, (2) that the healthy placenta contains little or no G-CSF mRNA in vivo, (3) the placenta at term has a far greater capacity to produce G-CSF, when stimulated, than does the placenta before term, and (4) that although the placenta does not normally produce G-CSF in vivo, it has the capacity of generating very large quantities of G-CSF continuously over at least several days.