Human Fetal Blood Research Articles

Comparison of DNA methylation profiles in human fetal and adult red blood cell progenitors.

BackgroundDNA methylation is an epigenetic modification that plays an important role during mammalian development. Around birth in humans, the main site of red blood cell production moves from the fetal liver to the bone marrow. DNA methylation changes at the β-globin locus and a switch from fetal to adult hemoglobin production characterize this transition. Understanding this globin switch may improve the treatment of patients with sickle cell disease and β-thalassemia, two of the most common Mendelian diseases in the world. The goal of our study was to describe and compare the genome-wide patterns of DNA methylation in fetal and adult human erythroblasts.MethodsWe used the Illumina HumanMethylation 450 k BeadChip to measure DNA methylation at 402,819 CpGs in ex vivo-differentiated erythroblasts from 12 fetal liver and 12 bone marrow CD34+ donors.ResultsWe identified 5,937 differentially methylated CpGs that overlap with erythroid enhancers and binding sites for erythropoiesis-related transcription factors. Combining this information with genome-wide association study results, we show that erythroid enhancers define particularly promising genomic regions to identify new genetic variants associated with fetal hemoglobin (HbF) levels in humans. Many differentially methylated CpGs are located near genes with unanticipated roles in red blood cell differentiation and proliferation. For some of these new candidate genes, we confirm the correlation between DNA methylation and gene expression levels in red blood cell progenitors. We also provide evidence that DNA methylation and genetic variation at the β-globin locus independently control globin gene expression in adult erythroblasts.ConclusionsOur DNA methylome maps confirm the widespread dynamic changes in DNA methylation that occur during human erythropoiesis. These changes tend to happen near erythroid enhancers, further highlighting their importance in erythroid regulation and HbF production. Finally, DNA methylation may act independently of the transcription factor BCL11A to repress fetal hemoglobin production. This provides cues on strategies to more efficiently re-activate HbF production in sickle cell disease and β-thalassemia patients.Electronic supplementary materialThe online version of this article (doi:10.1186/s13073-014-0122-2) contains supplementary material, which is available to authorized users.

Human fetoplacental and fetal liver blood flow after maternal glucose loading: a cross-sectional observational study.

To study umbilical vein and fetal liver blood flow related to fetal anthropometric measures following maternal oral glucose loading. Experimental design in a cross-sectional observational study. University hospital. A total of 113 low-risk pregnancies (30-32weeks of gestation). Ultrasound Doppler measurements of umbilical vein and ductus venosus blood flow (ml/min) before and 2h after completed 75-g oral glucose tolerance test (OGTT). Liver blood flow was defined as the umbilical vein blood flow minus ductus venosus blood flow. Changes in umbilical vein and fetal liver blood flow following OGTT related to fetal biometric measurements. In the fasting state, fetal abdominal circumference z-scores did not correlate with any of the flow parameters; 120min after glucose loading, the z-scores correlated positively with the changes in umbilical vein (r=0.25, p=0.010) and fetal liver blood flow (r=0.25, p=0.009), but not with those in ductus venosus (p=0.84). In simultaneous multiple linear regression analyses, the effects of the changes in umbilical vein or fetal liver blood flow after OGTT on the fetal abdominal circumference z-scores were almost equal to or greater than other parameters related to fetal size (body mass index, fasting plasma glucose, parity, and sex). Fetal heart rate increased after OGTT, but did not influence the association between the blood flow parameters and fetal abdominal circumference z-scores. Changes in umbilical vein and fetal liver blood flow after glucose loading were positively related to fetal abdominal size.

Potential of human fetal chorionic stem cells for the treatment of osteogenesis imperfecta.

Osteogenesis imperfecta (OI) is a genetic bone pathology with prenatal onset, characterized by brittle bones in response to abnormal collagen composition. There is presently no cure for OI. We previously showed that human first trimester fetal blood mesenchymal stem cells (MSCs) transplanted into a murine OI model (oim mice) improved the phenotype. However, the clinical use of fetal MSC is constrained by their limited number and low availability. In contrast, human fetal early chorionic stem cells (e-CSC) can be used without ethical restrictions and isolated in high numbers from the placenta during ongoing pregnancy. Here, we show that intraperitoneal injection of e-CSC in oim neonates reduced fractures, increased bone ductility and bone volume (BV), increased the numbers of hypertrophic chondrocytes, and upregulated endogenous genes involved in endochondral and intramembranous ossification. Exogenous cells preferentially homed to long bone epiphyses, expressed osteoblast genes, and produced collagen COL1A2. Together, our data suggest that exogenous cells decrease bone brittleness and BV by directly differentiating to osteoblasts and indirectly stimulating host chondrogenesis and osteogenesis. In conclusion, the placenta is a practical source of stem cells for the treatment of OI.

Unique monoclonal antibodies specifically bind surface structures on human fetal erythroid blood cells

BackgroundContinuing efforts in development of non-invasive prenatal genetic tests have focused on the isolation of fetal nucleated red blood cells (NRBCs) from maternal blood for decades. Because no fetal cell-specific antibody has been described so far, the present study focused on the development of monoclonal antibodies (mAbs) to antigens that are expressed exclusively on fetal NRBCs.Methods: Mice were immunized with fetal erythroid cell membranes and hybridomas screened for Abs using a multi-parameter fluorescence-activated cell sorting (FACS). Selected mAbs were evaluated by comparative FACS analysis involving Abs known to bind erythroid cell surface markers (CD71, CD36, CD34), antigen-i, galactose, or glycophorin-A (GPA). Specificity was further confirmed by extensive immunohistological and immunocytological analyses of NRBCs from umbilical cord blood and fetal and adult cells from liver, bone marrow, peripheral blood, and lymphoid tissues.Results: Screening of 690 hybridomas yielded three clones of which Abs from 4B8 and 4B9 clones demonstrated the desired specificity for a novel antigenic structure expressed on fetal erythroblast cell membranes. The antigenic structure identified is different from known surface markers (CD36, CD71, GPA, antigen-i, and galactose), and is not present on circulating adult erythroid cells, except for occasional detectability in adult bone marrow cells.Conclusions:The new mAbs specifically bind the same or highly overlapping epitopes of a surface antigen that is almost exclusively expressed on fetal erythroid cells. The high specificity of the mAbs should facilitate development of simple methods for reliable isolation of fetal NRBCs and their use in non-invasive prenatal diagnosis of fetal genetic status.

Rapid and efficient reprogramming of human fetal and adult blood CD34+ cells into mesenchymal stem cells with a single factor

The direct conversion of skin cells into somatic stem cells has opened new therapeutic possibilities in regenerative medicine. Here, we show that human induced mesenchymal stem cells (iMSCs) can be efficiently generated from cord blood (CB)- or adult peripheral blood (PB)-CD34(+) cells by direct reprogramming with a single factor, OCT4. In the presence of a GSK3 inhibitor, 16% of the OCT4-transduced CD34(+) cells are converted into iMSCs within 2 weeks. Efficient direct reprogramming is achieved with both episomal vector-mediated transient OCT4 expression and lentiviral vector-mediated OCT4 transduction. The iMSCs express MSC markers, resemble bone marrow (BM)-MSCs in morphology, and possess in vitro multilineage differentiation capacity, yet have a greater proliferative capacity compared with BM-MSCs. Similar to BM-MSCs, the implanted iMSCs form bone and connective tissues, and are non-tumorigenic in mice. However, BM-MSCs do not, whereas iMSCs do form muscle fibers, indicating a potential functional advantage of iMSCs. In addition, we observed that a high level of OCT4 expression is required for the initial reprogramming and the optimal iMSC self-renewal, while a reduction of OCT4 expression is required for multilineage differentiation. Our method will contribute to the generation of patient-specific iMSCs, which could have applications in regenerative medicine. This discovery may also facilitate the development of strategies for direct conversion of blood cells into other types of cells of clinical importance.

Isolation of CD34+ Cells from Human Fetal Liver and Cord Blood

Isolation of CD34+ Cells from Human Fetal Liver and Cord Blood

The Role of IL-4 Signaling in CD8+ Innate-Like Lymphocyte Development.

Abstract 2161The innate and adaptive arms of the immune system collaborate to protect the host against invading pathogens and perform immune surveillance against malignant transformation. As key effectors of the adaptive immune system, conventional T cells develop in the thymus and exit to the periphery as naïve cells, requiring antigenic stimulation and subsequent differentiation to gain effector functions, such as cytokine secretion or cytolytic activity. In contrast to conventional T cells, non-conventional T lymphocytes possess characteristics of innate immune cells, such as expression of surface markers associated with activation/memory and acquisition of effector function during thymic development, and thus are termed innate-like lymphocytes (ILLs). Recently, an expanded population of CD8+ ILLs was identified in mice with a mutation in the T cell receptor signaling protein SLP-76 (SLP-76 Y145F mice). These CD8+ ILLs are characterized by expression of activation/memory markers CD44 and CD122, the expression of the T-box transcription factor Eomesodermin (Eomes) and rapid production of IFN-γ after ex vivo stimulation. The development of these CD8+ ILLs occurs in a cell-extrinsic manner and requires IL-4. We demonstrate that IL-4 is sufficient to upregulate Eomes expression in wild-type CD8 single-positive (SP) thymocytes in short-term in vitro culture and potentiate CD8+ ILL development in fetal thymic organ culture. Using phospho-flow cytometry, we find that CD8+ ILLs from SLP-76 Y145F mice have increased STAT6 and Akt activation vs. CD8+ non-ILLs. In CD8SP thymocytes deficient in STAT6, Eomes expression is not upregulated in response to IL-4. In addition, we demonstrate that pharmacologic inhibition of Akt in SLP-76 Y145F fetal thymic organ culture blocks CD8+ ILL development and also prevents IL-4 induced Eomes upregulation in WT CD8SP thymocytes. Importantly, we have identified CD8+ ILLs in human fetal thymocytes and umbilical cord blood and found that IL-4 is sufficient to up-regulate Eomes expression in these cells. Taken together, our data suggest that IL-4 signaling via STAT6 and Akt pathways is required for IL-4 induction of Eomes expression and CD8+ ILL development. Understanding signal transduction pathways required for CD8+ ILL development will provide insight into the development of this unique lymphocyte subset that sits at the interface between innate and adaptive immunity and has been identified in human umbilical cord blood. Disclosures:No relevant conflicts of interest to declare.

Membrane proteins of human fetal primitive nucleated red blood cells

In humans, primitive fetal nucleated red blood cells (FNRBCs) are thought to be as vital for embryonic life as their counterpart, adult red blood cells (adult RBCs) are in later-gestation fetuses and adults. Unlike adult RBCs, the identity and functions of FNRBC proteins are poorly understood owing to a scarcity of FNRBCs for proteomic investigations. The study aimed to investigate membrane proteins of this unique cell type. We present here, the first report on the membrane proteome of human primitive FNRBCs investigated by two-dimensional liquid chromatography coupled with mass-spectrometry (2D-LCMS/MS) and bioinformatics analysis. A total of 273 proteins were identified, of which 133 (48.7%) were membrane proteins. We compared our data with membrane proteins of adult RBCs to identify common, and unique, surface membrane proteins. Twelve plasma membrane proteins with transmembrane domains and eight proteins with transmembrane domains but without known sub-cellular location were identified as unique-to-FNRBCs. Except for the transferrin receptor, all other 19 unique-to-FNRBC membrane proteins have never been described in RBCs. Reverse-transcriptase PCR (RT-PCR) and immunocytochemistry validated the 2D-LCMS/MS data. Our findings provide potential surface antigens for separation of primitive FNRBCs from maternal blood for noninvasive prenatal diagnosis, and to understand the biology of these rare cells.

Effect of mono-(2-ethylhexyl) phthalate on human and mouse fetal testis: In vitro and in vivo approaches

The present study was conducted to determine whether exposure to the mono-(2-ethylhexyl) phthalate (MEHP) represents a genuine threat to male human reproductive function. To this aim, we investigated the effects on human male fetal germ cells of a 10−5M exposure. This dose is slightly above the mean concentrations found in human fetal cord blood samples by biomonitoring studies. The in vitro experimental approach was further validated for phthalate toxicity assessment by comparing the effects of in vitro and in vivo exposure in mouse testes.Human fetal testes were recovered during the first trimester (7–12weeks) of gestation and cultured in the presence or not of 10−5M MEHP for three days. Apoptosis was quantified by measuring the percentage of Caspase-3 positive germ cells. The concentration of phthalate reaching the fetal gonads was determined by radioactivity measurements, after incubations with 14C-MEHP.A 10−5M exposure significantly increased the rate of apoptosis in human male fetal germ cells. The intratesticular MEHP concentration measured corresponded to the concentration added in vitro to the culture medium. Furthermore, a comparable effect on germ cell apoptosis in mouse fetal testes was induced both in vitro and in vivo.This study suggests that this 10−5M exposure is sufficient to induce changes to the in vivo development of the human fetal male germ cells.

Upregulating CXCR4 in human fetal mesenchymal stem cells enhances engraftment and bone mechanics in a mouse model of osteogenesis imperfecta.

Stem cells have considerable potential to repair damaged organs and tissues. We previously showed that prenatal transplantation of human first trimester fetal blood mesenchymal stem cells (hfMSCs) in a mouse model of osteogenesis imperfecta (oim mice) led to a phenotypic improvement, with a marked decrease in fracture rate. Donor cells differentiated into mature osteoblasts, producing bone proteins and minerals, including collagen type Iα2, which is absent in nontransplanted mice. This led to modifications of the bone matrix and subsequent decrease of bone brittleness, indicating that grafted cells directly contribute to improvement of bone mechanical properties. Nevertheless, the therapeutic effect was incomplete, attributing to the limited level of engraftment in bone. In this study, we show that although migration of hfMSCs to bone and bone marrow is CXCR4-SDF1 (SDF1 is stromal-derived factor) dependent, only a small number of cells present CXCR4 on the cell surface despite high levels of internal CXCR4. Priming with SDF1, however, upregulates CXCR4 to increase the CXCR4(+) cell fraction, improving chemotaxis in vitro and enhancing engraftment in vivo at least threefold in both oim and wild-type bone and bone marrow. Higher engraftment in oim bones was associated with decreased bone brittleness. This strategy represents a step to improve the therapeutic benefits of fetal cell therapy toward being curative.

Comparing Human Fetal Liver, Cord Blood and Adult Bone Marrow Stem/Progenitor Hematopoietic Cells As Cells of Origin of Human MLL Leukemias

Abstract 2956Acute leukemias in newborns, children, adults and elderly share the same name, but their genetic, biology and prognosis are significantly different. These differences may be explained by many factors including the nature of the recurrent genetic abnormalities, tolerance to chemotherapy, co-morbidities, etc. One noteworthy potential difference is the cell of origin in which the initial genetic event occurs, which can be a fetal liver, cord blood or adult bone marrow stem/progenitor cell. Genetically engineered mouse models of leukemias and gene expression studies on human acute lymphoblastic leukemias (ALL) suggest that leukemias developing in utero (i.e. in an early ontogenic cell of origin) are biologically distinct from child and adult leukemias. However, direct comparison of human hematopoietic stem/progenitor cells at different stages of ontogeny has not been tested experimentally.Over 70% of infant acute leukemias and 5–10% of adult leukemias exhibit rearrangements of the mixed-lineage leukemia gene (MLL). Therefore, MLL translocations are highly relevant oncogenes to investigate the leukemic potential of the different cells of origin. The MLL-ENL (MLL-MLLT1) fusion gene, from the t(11;19) (q23;p13.3), is one of the most frequent MLL fusion and can occur in infants and adults. It is found in both acute myeloid leukemias (AML) and ALL (both B-cell and T-cell ALL) and we have previously shown that it generates human B-ALL in immunodeficient mice when introduced into lineage depleted human cord blood cells using a retrovirus (Barabé et al, Science 2007).The same experimental design was used to study the cells of origin; CD34+ cells from human fetal liver (FL), cord blood (CB) and adult bone marrow (BM) were infected with either a retrovirus encoding MLL-ENL and an enhanced green fluorescent protein (EGFP) marker gene, or a control retrovirus encoding EGFP only, then injected into sub-lethally irradiated immunodeficient mice. After transduction with MLL-ENL, FL cells generated leukemias in 8/10 mice, CB cells in 6/6 mice and adult BM cells in only 2/7 mice, although four times more cells were transduced and injected. Adult BM cells were very difficult to infect with retroviruses and were clearly not as potent to reconstitute a human graft in immunodeficient mice in comparison to CB cells. All generated leukemias were B-ALL, regardless of the cell of origin. The leukemic phenotype (CD19+, HLA-DR+, CD20-, IgM-, IgG-, CD34 variable) was similar in all three cell types. Mice injected with MLL-ENL-transduced FL and adult BM cells that were not leukemic had a normal human graft but no EGFP cells. The frequency of leukemia-initiating cells (L-IC) was evaluated at 0.2–1% by limiting dilution in secondary mice and no significant differences were observed between the three cell types. Leukemic cells were harvested from the BM of primary mice and cultured in vitro under conditions supportive of both B-lymphoid and myeloid cells. All leukemias were able to grow in vitro and at least one culture derived from each cell type (FL, CB and adult BM) switched to a myeloid phenotype (monocytic morphology with CD33+ and loss of CD19), demonstrating that leukemias derived from all 3 cell types still have myeloid potential.Thus, our results suggest that MLL-ENL can generate leukemia in FL, CB and adult BM CD34+ cells. The lower penetrance of leukemia with adult BM cells is probably due to the difficulty to infect these cells and their limited reconstitution ability. MLL-ENL induces a leukemic program in all three cell types with similar clinical features, cell surface phenotype, frequency of L-IC and conserved bi-lineage potential (B and myeloid). Gene expression profiling and clonality studies are currently performed on leukemias generated from the 3 different cell types. So far, no significant differences between FL, CB and adult BM as cells of origin of MLL leukemias have been identified, suggesting that the nature of the oncogenic hit is probably more important than the ontogenic stage of the cell of origin. Disclosures:No relevant conflicts of interest to declare.

Colocalization in vivo and association in vitro of perlecan and elastin

We have colocalized elastin and fibrillin-1 with perlecan in extracellular matrix of tensional and weight-bearing connective tissues. Elastin and fibrillin-1 were identified as prominent components of paraspinal blood vessels, and posterior longitudinal ligament in the human fetal spine and outer annulus fibrosus of the fetal intervertebral disc. We also colocalized perlecan with a synovial elastic basal lamina, where the attached synovial cells were observed to produce perlecan. Elastin, fibrillin-1 and perlecan were co-localized in the intima and media of small blood vessels in the synovium and in human fetal paraspinal blood vessels. Elastic fibers were observed at the insertion point of the anterior cruciate ligament to bone in the ovine stifle joint where they colocalized with perlecan. Elastin has not previously been reported to be spatially associated with perlecan in these tissues. Interactions between the tropoelastin and perlecan heparan sulfate chains were demonstrated using quartz crystal microbalance with dissipation solid phase binding studies. Electrostatic interactions through the heparan sulfate chains of perlecan and core protein mediated the interactions with tropoelastin, and were both important in the coacervation of tropoelastin and deposition of elastin onto perlecan immobilized on the chip surface. This may help us to understand the interactions which are expected to occur in vivo between the tropoelastin and perlecan to facilitate the deposition of elastin and formation of elastic microfibrils in situ and would be consistent with the observed distributions of these components in a number of connective tissues.

Transplantation of human fetal blood stem cells in the osteogenesis imperfecta mouse leads to improvement in multiscale tissue properties

AbstractOsteogenesis imperfecta (OI or brittle bone disease) is a disorder of connective tissues caused by mutations in the collagen genes. We previously showed that intrauterine transplantation of human blood fetal stem/stromal cells in OI mice (oim) resulted in a significant reduction of bone fracture. This work examines the cellular mechanisms and mechanical bone modifications underlying these therapeutic effects, particularly examining the direct effects of donor collagen expression on bone material properties. In this study, we found an 84% reduction in femoral fractures in transplanted oim mice. Fetal blood stem/stromal cells engrafted in bones, differentiated into mature osteoblasts, expressed osteocalcin, and produced COL1a2 protein, which is absent in oim mice. The presence of normal collagen decreased hydroxyproline content in bones, altered the apatite crystal structure, increased the bone matrix stiffness, and reduced bone brittleness. In conclusion, expression of normal collagen from mature osteoblast of donor origin significantly decreased bone brittleness by improving the mechanical integrity of the bone at the molecular, tissue, and whole bone levels.

Components of plastic: experimental studies in animals and relevance for human health

Components used in plastics, such as phthalates, bisphenol A (BPA), polybrominated diphenyl ethers (PBDE) and tetrabromobisphenol A (TBBPA), are detected in humans. In addition to their utility in plastics, an inadvertent characteristic of these chemicals is the ability to alter the endocrine system. Phthalates function as anti-androgens while the main action attributed to BPA is oestrogen-like activity. PBDE and TBBPA have been shown to disrupt thyroid hormone homeostasis while PBDEs also exhibit anti-androgen action. Experimental investigations in animals indicate a wide variety of effects associated with exposure to these compounds, causing concern regarding potential risk to human health. For example, the spectrum of effects following perinatal exposure of male rats to phthalates has remarkable similarities to the testicular dysgenesis syndrome in humans. Concentrations of BPA in the foetal mouse within the range of unconjugated BPA levels observed in human foetal blood have produced effects in animal experiments. Finally, thyroid hormones are essential for normal neurological development and reproductive function. Human body burdens of these chemicals are detected with high prevalence, and concentrations in young children, a group particularly sensitive to exogenous insults, are typically higher, indicating the need to decrease exposure to these compounds.

A fractal analysis of human fetal pituitary blood vessels

Fractal analysis allows a non‐Euclidian evaluation of the tissue‐blood vessels ratio and distribution. The fractal dimension varies from 1 to 2. Di Ieva et al have shown that fractal dimension is a good quantitator for microvasculature of normal (2007) and adenomatous (2008) pituitaries.We present here a fractal analysis study of pituitary vasculature in human fetuses of 9‐24 weeks obtained from terminations with ethical approval, performed on digital images taken from toluidine blue‐stained semithin sections and fluorescence microscopy after lectin binding or propidium iodide.Both light microscopy after toluidine blue and fluorescence microscopy are suitable for fractal analysis; fluorescence in red gave the best results. The fractal indices varied from 1.41 to 1.86, progressively decreasing from 9 to 24 weeks; the distribution of individual values varied following a logarithmic curve, thus demonstrating that in each case, there is a limit, over which the vessels fractal dimension does not increase; the ratio cells/blood vessels varies from 1.15 (9‐10 weeks) to 0.91 (18 to 24 weeks).These data show that fractal analysis is suitable for the study of dynamic changes in blood vessels in the human fetal pituitary, during ontogenesis, giving a quantitative image of its progressive development and time‐related evolution, complementary to the data derived from morphometric vascular density measurements.

Red Cell Volume Can Be Accurately Determined in Sheep Using a Nonradioactive Biotin Label

The sheep has served as an informative animal model for investigation of human fetal and newborn erythropoiesis and red blood cell (RBC) kinetics. We previously validated the permanent label (14C)cyanate for measuring red cell volume (RCV) in sheep. Here, we validate biotin labeling of RBCs as a nonradioactive method for measuring RCV in sheep with the anticipation that it can be applied in studies of human infants. The RCV was determined simultaneously using two techniques for quantitation of the biotin label. The first one quantified total blood concentration of biotin label on biotin-labeled RBCs using (125I)streptavidin. The second one enumerated biotin-labeled RBCs by flow cytometry after incubation with fluorescein-conjugated avidin. RCV measurements made using the two biotin quantitation techniques were validated against both (14C)cyanate and 51Cr as reference methods. Both biotin techniques produced RCV values that agreed well with the reference methods and with each other, producing correlation coefficients averaging >or =0.93. Sequential repetitive measurements in the same animal also agreed with the (14C)cyanate method and each other (average difference <10%). These results establish biotin-labeled RBCs as an accurate method for performing RCV measurements in sheep. This biotin method can be applied in studies that model neonatal erythropoiesis.

Blood pressure estimation in the human fetal descending aorta

The objectives of this study were to estimate fetal blood pressure non-invasively from two-dimensional color Doppler-derived aortic blood flow and diameter waveforms, and to compare the results with invasively derived human fetal blood pressures available from the literature. Aortic pressures were calculated from digitally recorded color Doppler cineloops of the fetal descending aorta by applying the Womersley model in combination with the two-element Windkessel model, assuming constant pulse wave velocity during the second half of pregnancy. The results were compared with invasively derived human fetal blood pressures obtained from the literature. In 21 normal pregnancies the estimated mean aortic pressure regression line increased linearly from 28 mmHg at 20 weeks of gestation to 45 mmHg at 40 weeks of gestation. The pulse pressure based on the regression line increased linearly from 21 mmHg at 20 weeks of gestation to 29 mmHg at 40 weeks of gestation. The aortic compliance exhibited a log linear relationship with the gestational age and a statistically significant eightfold increase was observed between 20 and 40 weeks. The aortic downstream peripheral resistance exhibited an exponentially decaying relationship across the same gestational age range. Non-invasively derived aortic systolic and diastolic aortic pressures were comparable with previously reported invasively derived systolic and diastolic umbilical arterial pressures; however, the mean pressures differed significantly from those reported in the umbilical artery in a separate study. The aortic systolic pressures calculated in this study were significantly higher than invasively derived left ventricular systolic pressures that have been previously reported in the literature. This study demonstrates the feasibility of estimating arterial blood pressure in the human fetus. The method described is of potential use in assessing fetal blood pressure non-invasively, particularly for studying relative changes with time.

Intrauterine transplantation of human fetal mesenchymal stem cells from first-trimester blood repairs bone and reduces fractures in osteogenesis imperfecta mice

AbstractThe inherited skeletal dysplasia osteogenesis imperfecta (OI) results in multiple fractures and is currently treated empirically. We transplanted human first-trimester fetal blood mesenchymal stem cells (MSCs) into homozygous oim mice in utero. This resulted in a two-thirds reduction in long bone fractures (P < .01), with fewer fractures per mouse (median 1, range 0-2 in mice that received transplants vs median 3, range 1-5 in mice that did not receive transplants by 12 weeks, P < .01). Nearly all mice that did not receive transplants had fractures (47 [97.9%] of 48), in contrast to 17 (58.6%) of 29 4- to 12-week-old mice that received transplants (P < .01). Transplantation was associated with increased bone strength (P < .01), thickness (P < .01), and length (P < .01), and normalization/reduction of growth plate height in 4- to 12-week-old oim was reduced in mice that underwent transplantion (P < .001). More donor cells were found in bone tissues compared with other organs (P < .001), with cells clustered in areas of active bone formation and remodeling, and at sites of fracture healing. Donor cells found in the bone expressed osteoblast lineage genes, and produced the extracellular bone structural protein osteopontin. Finally, MSC transplantation decreased bone hydroxyproline content. In conclusion, intrauterine transplantation of fetal MSCs markedly reduced fracture rates and skeletal abnormalities in a mouse model of the intermediate severity type III OI, suggesting a scientific basis for MSC treatment of affected human fetuses.

Characterization of human fetal cord blood steroid profiles in relation to fetal sex and mode of delivery using temperature-dependent inclusion chromatography and principal component analysis (PCA)

In the present work, human male and female fetal cord blood samples were purified, selectively extracted and separated to examine a fraction of steroids ranging from polar estetrol to relatively non-polar progesterone using solid phase extraction based on C-18 tubes and β-cyclodextrin driven temperature dependent inclusion chromatography. Resulting UV diode array chromatographic patterns revealed the presence of 27 peaks. Chromatographic patterns of UV detected steroids were analyzed using principal components analysis which revealed differences between male/female and labour/not-in-labour clusters. Quantitative analysis of nine identified steroids including: estetrol, 17β-estradiol, estrone, estriol, cortisol, cortisone, progesterone, 20α-hydroxyprogesterone and 17α-hydroxyprogesterone were not significantly different between males and females. Significant differences between male and female fetuses were related to as yet unidentified compounds. Four peaks were significantly different with labour which corresponded with cortisol, cortisone and two unidentified compounds. This protocol may distinguish significant differences between clinical groups that are not readily identifiable using univariate measurements of single steroids or different low molecular mass biomarkers. Moreover, we have provided new evidence that despite the absence of testosterone there are number of steroids and low molecular mass compounds that differ between male and female fetuses.

Human First-Trimester Fetal MSC Express Pluripotency Markers and Grow Faster and Have Longer Telomeres Than Adult MSC

The biological properties of stem cells are key to the success of cell therapy, for which MSC are promising candidates. Although most therapeutic applications to date have used adult bone marrow MSC, increasing evidence suggests that MSC from neonatal and mid-gestational fetal tissues are more plastic and grow faster. Fetal stem cells have been isolated earlier in development, from first-trimester blood and hemopoietic organs, raising the question of whether they are biologically closer to embryonic stem cells and thus have advantages over adult bone marrow MSC. In this study, we show that human first-trimester fetal blood, liver, and bone marrow MSC but not adult MSC express the pluripotency stem cell markers Oct-4, Nanog, Rex-1, SSEA-3, SSEA-4, Tra-1-60, and Tra-1-81. In addition, fetal MSC, irrespective of source, had longer telomeres (p < .001), had greater telomerase activity (p < .01), and expressed more human telomerase reverse transcriptase (p < .01). Fetal MSC were also more readily expandable and senesced later in culture than their adult counterparts (p < .01). Compared with adult MSC, first-trimester fetal tissues constitute a source of MSC with characteristics that appear advantageous for cell therapy.