Differential influence of maternal and fetal pregnancy factors on the in-vitro induction of human regulatory T cells: a preliminary study.

PROBLEM: Given the important role of regulatory T cells (Treg) for successful pregnancy, the ability of soluble maternal and fetal pregnancy factors to induce human Treg was investigated. METHOD OF STUDY: Peripheral blood mononuclear cells (PBMCs) or isolated CD4+CD25‒ cells were cultured in the presence of pooled second or third trimester pregnancy sera, steroid hormones or supernatants from placental explants, and the numbers and function of induced CD4+CD25+FOXP3+ Treg were analysed. RESULTS: Third trimester pregnancy sera and supernatants of early placental explants, but not sex steroid hormones, induced an increase of Tregs from PBMCs. Early placental supernatant containing high levels of tumour necrosis factor-α, interferon-γ, interleukins -1, -6 and -17, soluble human leucocyte antigen-G, and transforming growth factor-ß1, increased the proportion of Treg most effectively and was able to induce interleukin-10-secreting-Treg from CD4+CD25‒cells. CONCLUSIONS: Compared with circulating maternal factors, placental- and fetal-derived factors appear to exert a more powerful effect on numerical changes of Treg, thereby supporting fetomaternal tolerance during human pregnancy.

Generation of an osteogenic graft from human placenta and placenta-derived mesenchymal stem cells.

The objective of the study was to determine the feasibility of generating a biodegradable, stem cell-loaded osteogenic composite graft from human placenta. Initially, a scaffold from human chorion membrane was produced. Human placenta mesenchymal stem cells (MSCs) derived from either first-trimester chorionic villi or term chorion membrane were differentiated osteogenically on this scaffold. Outgrowth, adherence, and osteogenic differentiation of cells were assessed by immunohistochemistry (IHC), scanning electron microscopy, protein expression, and real-time polymerase chain reaction (RT-PCR). Our results showed that a cell-free extracellular matrix scaffold can be generated from human chorion. Seeded MSCs densely adhered to that scaffold and were osteogenically differentiated. Calcium and alkaline phosphatase were detected in the cell-scaffold constructs as a proof of mineralization and findings were confirmed by IHC and RT-PCR results. This study shows for the first time that generation of an osteogenic composite graft using placental tissue is feasible. It might allow therapeutic application of autologous or allogeneic grafts in congenital skeletal defects by means of a composite graft.

Neurogenic characteristics of placental stem cells in preeclampsia.

OBJECTIVE: Preeclampsia is associated with perinatal brain injury. Autologous placenta stem cell transplantation represents a promising future treatment option for neuroregeneration. The aim of this study was to compare the neuroregenerative capacity of preeclampsia-placenta stem cells to previously characterized placentas from uncomplicated pregnancies. STUDY DESIGN: Placenta stem cells from amnion (epithelium, mesenchyme) and chorion were assessed for cell surface markers and the formation of neuronal-like cells, oligodendrocytes and their progenitors in culture. RESULTS: Markers of preeclampsia-placenta stem cells were different from uncomplicated pregnancies-placenta stem cells in amnion epithelium and chorion, but not in amnion mesenchyme. Similarly to uncomplicated pregnancies-placenta stem cells, preeclampsia-placenta stem cells derived from amnion and chorion differentiated preferably into nestin-positive stem/progenitor cells and Tuj-1-positive neurons. However, other important markers were varying after neurogenic differentiation of uncomplicated pregnancies- and preeclampsia-placenta stem cells. CONCLUSION: Surface marker expression patterns of preeclampsia-placenta stem cell's and uncomplicated pregnancies-placenta stem cell's differ. In vitro differentiation assays, however, provide evidence that both preeclampsia-placenta stem cells and uncomplicated pregnancies-placenta stem cells are comparably suitable for neuroregeneration purposes.

Turning placenta into brain: placental mesenchymal stem cells differentiate into neurons and oligodendrocytes.

OBJECTIVE: We aimed to induce neural stem (NSC) and progenitor cells (NPC) from human placental tissues. STUDY DESIGN: Placental stem cells from first-trimester placental chorionic villi and term chorion were isolated. Neural differentiation was initiated with plating on collagen, retinoic acid, and/or human brain-derived neurotrophic factor and epidermal and fibroblast growth factor. Differentiation into neurons, oligodendrocytes, and astrocytes was monitored by immunohistochemistry. Two-dimensional polyacrylamide gel electrophoresis, high-performance liquid chromatography, and tandem mass spectrometry were used to identify proteins involved in the differentiation. RESULTS: Differentiated cells were mostly immediately postmitotic with some more but not fully mature postmitotic neurons. Neurons had dopaminergic or serotonergic character. Some cells differentiated into predominantly immature oligodendrocytes. Upon differentiation, neuron-specific proteins were up-regulated, whereas placental proteins were reduced. CONCLUSION: Stem cells derived from human placenta can be differentiated into neural progenitors.

Concise review: isolation and characterization of cells from human term placenta: outcome of the first international Workshop on Placenta Derived Stem Cells.

Placental tissue draws great interest as a source of cells for regenerative medicine because of the phenotypic plasticity of many of the cell types isolated from this tissue. Furthermore, placenta, which is involved in maintaining fetal tolerance, contains cells that display immunomodulatory properties. These two features could prove useful for future cell therapy-based clinical applications. Placental tissue is readily available and easily procured without invasive procedures, and its use does not elicit ethical debate. Numerous reports describing stem cells from different parts of the placenta, using nearly as numerous isolation and characterization procedures, have been published. Considering the complexity of the placenta, an urgent need exists to define, as clearly as possible, the region of origin and methods of isolation of cells derived from this tissue. On March 23-24, 2007, the first international Workshop on Placenta Derived Stem Cells was held in Brescia, Italy. Most of the research published in this area focuses on mesenchymal stromal cells isolated from various parts of the placenta or epithelial cells isolated from amniotic membrane. The aim of this review is to summarize and provide the state of the art of research in this field, addressing aspects such as cell isolation protocols and characteristics of these cells, as well as providing preliminary indications of the possibilities for use of these cells in future clinical applications.

Placental mesenchymal stem cells as potential autologous graft for pre- and perinatal neuroregeneration.

OBJECTIVE: Mesenchymal stem cells (MSCs) have a broad differentiation potential. We aimed to determine if MSCs are present in fetal membranes and placental tissue and to assess their potential to differentiate into neurogenic and mesodermal lineages. STUDY DESIGN: MSCs isolated from first and third trimester chorion and amnion and first trimester chorionic villi and characterized morphologically and by flourescence-activated cell sorting analysis. Their ability to mature under different culture conditions into various cells of mesodermal and neuroectodermal cell lines was assessed by immuno- and cytochemical staining. RESULTS: Independent of gestational age, cells isolated from fetal membranes and placenta showed typical MSC phenotype (positive for CD166, CD105, CD90, CD73, CD49e, CD44, CD29, CD13, MHC I; negative for CD14, CD34, CD45, MHC II) and were able to differentiate into mesodermal cells expressing cell markers/cytologic staining consistent with mature chondroblasts, osteoblasts, adipocytes, or myocytes and into neuronal cells presenting markers of various stages of maturation. The differentiation pattern was mainly dependent on cell type. CONCLUSION: Mesenchymal cells from chorion, amnion, and villous stroma can be differentiated into neurogenic, chondrogenic, osteogenic, adipogenic, and myogenic lineage. Placental tissue obtained during prenatal chorionic villous sampling or at delivery might be an ideal source for autologous stem cell graft for peripartum neuroregeneration and other clinical issues.

Fluid Shear Stress Reduces 11ss-Hydroxysteroid Dehydrogenase Type 2.

-In pregnancy, invading trophoblasts represent the inner vascular border of maternal spiral arteries and are exposed to elevated shear stress (ss) in hypertensive disorders. Intracellular cortisol availability is regulated by 11ss-hydroxysteroid dehydrogenases (11ss-HSDs), thus determining body fluid volume and vascular responses. The impact of ss on 11ss-HSD2 activity was studied in the human JEG-3 cell line, a model for trophoblasts. JEG-3 cells do not express 11ss-HSD1; however, 11ss-HSD2 message and activity are measured via cortisol/cortisone conversion in cell lysates, and both are reduced by ss. The reduction in 11ss-HSD2 activity via ss is dose dependent and completely reversible after the discontinuation of ss. cAMP-dependent protein kinase A activation increased the 11ss-HSD2 activity yet did not prevent the ss response. The ss response was completely protein kinase C independent. The mitogen-activated protein kinase kinase inhibitor PD-098059 enhanced 11ss-HSD2 activity in static conditions yet only ameliorated the ss effect. Cytochalasin D disrupts focal adhesion (FA)-cytoskeleton interactions and abolished the ss-induced tyrosine phosphorylation of FA kinase dose-dependently, thus maintaining 11ss-HSD2 activity. The 11ss-HSD2 activity was only partially restored by the tyrosine kinase inhibitor genistein; however, herbimycin A almost completely abolished the ss effect on 11ss-HSD2 activity. In conclusion, JEG-3 cells express 11ss-HSD2, which is downregulated by ss. Regulatory mechanisms involve transcriptional control and require intact FA-cytoskeleton signaling and phosphorylation of FA kinase. Thus, ss adds to an enhanced intracellular availability of cortisol, which may ultimately support a vasoconstrictive vascular response.