The association between chorionic villus sampling and preeclampsia.

OBJECTIVE: To determine whether an association exists between prenatal diagnostic procedures and preeclampsia. METHODS: All women who underwent invasive prenatal diagnosis and were not at high risk for preeclampsia were identified during a 15-month period and matched by age with women who had not had invasive prenatal diagnosis. The association between prenatal diagnosis [amniocentesis and chorionic villus sampling (CVS)] and the development of preeclampsia was assessed in univariable and multivariable analyses. RESULTS: Six-hundred and fifty-three women who underwent prenatal diagnosis (501 by amniocentesis and 152 by CVS) were matched by age with 653 women who did not undergo the test. In multivariable analysis, the factors that remained significantly associated with preeclampsia were (1) maternal age less than 25 years (OR 7.4, 95% CI 23.3-23.6); (2) nulliparity (OR 2.7, 95% CI 1.1-6.9); and (3) having had a CVS as a nulliparous woman (OR 4.2, 95% CI 1.4-12.6). CONCLUSION: These data suggest that CVS is associated with the subsequent development of preeclampsia in nulliparous women; this relationship should be confirmed in further studies.

Value of amniocentesis versus fetal tissue for cytogenetic analysis in cases of fetal demise.

OBJECTIVE: Use of fetal tissue for cytogenetic analysis in cases of second- and third-trimester fetal demise frequently results in unacceptably high failure rates. We reviewed our ongoing use of amniocentesis prior to uterine evacuation to determine if this provided a better source of cells for cytogenetic analysis. METHODS: We compared cytogenetic results using fetal tissues obtained following uterine evacuation to our ongoing use of amniotic fluid cell obtained by transabdominal amniocentesis prior to uterine evacuation from 2003 to 2008. RESULTS: In 49 of the 63 cases evaluated by fetal tissue biopsies performed after uterine evacuation, a karyotypic analysis was obtained (77.8%). Among the 38 cases evaluated by amniocentesis, an amniotic fluid sample and fetal cytogenetic results were obtained in all 38 (100%) cases. CONCLUSION: Our findings indicate that amniocentesis is a more reliable source of cytogenetic information than fetal tissue in cases of second- and third-trimester fetal demise.

Endothelial precursor cells in the peripheral blood of pregnant women.

OBJECTIVE: To determine whether primitive endothelial precursor cells are present in the peripheral blood of pregnant compared with nonpregnant subjects and whether these precursor cells are of fetal or maternal origin. METHODS: Peripheral blood mononuclear cells from 13 pregnant women in the second trimester and from ten nonpregnant women and men were cultured for 8-10 weeks under conditions that promoted endothelial cell development. Early outgrowth (1 week culture) and late outgrowth (4-6 weeks) colonies were observed, their endothelial nature was investigated, and fluorescence in situ hybridization was performed to determine the origin of the colonies from pregnant women's specimens. RESULTS: Peripheral blood mononuclear cell cultures from all pregnant women and all nonpregnant controls yielded early-outgrowth endothelial cells. Late-outgrowth endothelial cells were observed in 61.5% (eight of 13) of pregnant subjects, but in none of the ten nonpregnant controls (chi(2) test; P <.01). The adherent cells stained positively for von Willebrand factor and incorporated Dil-Ac-LDL, confirming their endothelial origin. Fluorescence in situ hybridization analysis showed only X chromosome-specific signals and no Y chromosome-specific signals in the cells from the late-outgrowth endothelial cells in all pregnant women carrying either a male (n = 5) or a female (n = 8) fetus. CONCLUSION: Primitive endothelial precursor cells are present in most pregnant women during the second trimester. These cells appear to be of maternal origin.

High-resolution two-dimensional electrophoretic survey of serum protein genetic types in Schmiedeleut Hutterites.

High-resolution, two-dimensional electrophoresis (2DE) was used to examine allele frequencies in eight serum protein marker systems and to screen for rare or previously undescribed alleles in 152 members of the Schmiedeleut branch of the Hutterite Brethren. The results include the first report of α2 -HS glycoprotein, apolipoprotein E, and SPPM-158 frequencies and haptoglobin 1F and 2S subtype frequencies in the Hutterites. Designed as part of ongoing genetic studies in this reproductively isolated population, this study was done to determine which markers might correlate with medical features or could be useful in population studies. Prior studies of erythrocyte surface and enzymatic markers, lymphocyte surface and enzymatic markers, and serum proteins by other investigators have identified common, rare, and private markers in approximately 40 polymorphic systems. This study included five serum protein markers that were not examined in previous studies. The study identified a 2DE marker, SPPM-158, that was later confirmed in other populations to be a ubiquitous serum protein polymorphism. Allele frequencies for α2 -HS glycoprotein, apolipoprotein E, group-specific globulin, haptoglobin, SPPM-158, α1 -antitrypsin, apolipoprotein A-IV, and transferrin are presented. The first five of these had allele frequencies useful for population studies. We did not find any rare or private variants with 2DE in these systems. Overall, the 2DE data were in good agreement with prior studies in the Hutterites and relevant European populations.

Culture of cells from maternal circulation, in conditions favoring fetal endothelial cell expansion, does not facilitate the preferential expansion of circulating fetal cells.

OBJECTIVES: To establish optimal culture conditions for fetal endothelial cells, and determine whether these can be used for preferential expansion of fetal cells from maternal blood. METHODS: Human adult microvascular and umbilical vein endothelial cells were cultured in the presence of colony-stimulating factor-1 (CSF-1), placental growth factor (PlGF), and transforming growth factor-beta1 (TGF-beta1). The effect of each cytokine was assessed. We expanded peripheral blood mononuclear cells (PBMCs) from 18 pregnant women using the conditions most favorable to fetal cells; in specimens from women carrying male fetuses (n = 9), cell origin was determined by PCR (SRY locus). RESULTS: The optimal concentrations of CSF-1, PlGF and TGF-beta1 were 10, 100, and 5 ng/ml, respectively. PBMCs from maternal blood expanded in the presence or absence of the cytokines; PCR analysis showed no Y sequences in cultured maternal samples. CONCLUSION: Optimal concentrations of CSF-1, PlGF and TGF-beta1 for preferential expansion of fetal endothelial cells were determined in model cultures. However, when these conditions were applied to maternal blood samples, no fetal cells could be detected based on PCR for SRY in women carrying male fetuses.

The human gynome.

This year marks the 50th anniversary of the identification of the 3-dimensional structure of the DNA double helix and the completion of the US Human Genome Project. Now that we have completed the human genome sequence, what have we learned? How will this information benefit humankind? And, what are the implications for our patients in obstetrics and gynecology? Perhaps the biggest surprise is that there are only approximately 30,000 human genes, far fewer than earlier estimated. I propose the term "gynome" to describe that part of the human genome that is unique to women. We have learned that manifestations of diseases and therapeutic response can be gender specific. A major challenge is to define the interplay of the genetic variations of women with variations in their environment and lifestyle. Ultimately, this should lead to improved diagnosis of disease, earlier detection of genetic predispositions to disease, the design of more effective drugs, and gene therapy.

Culture of fetal cells from maternal blood for prenatal diagnosis.

The isolation and analysis of fetal cells from maternal blood would allow non-invasive prenatal genetic screening and diagnosis. Over the past decade, progress has been made towards this goal using various enrichment strategies and analysis by fluorescence in-situ hybridization with chromosome-specific probes and PCR. One method that is currently being explored involves culturing fetal cells. Developing conditions which allow the number of fetal-derived cells to expand in culture and the number of maternally derived cells to be suppressed in culture may lead to a new selection process for obtaining fetal cells. Culturing of fetal cells from maternal blood could make possible conventional metaphase analysis of fetal cells for diagnosis of chromosomal abnormalities.

Culture of endothelial cells isolated from maternal blood using anti-CD105 and CD133.

OBJECTIVES: We hypothesized that fetal cells in maternal blood that do not respond to hematopoietic culture conditions represent endothelial cells. We investigated whether endothelial progenitor cells of fetal origin may be selected from maternal blood on the basis of their expression of CD133 or CD105 and expanded in culture. METHODS: Peripheral blood mononuclear cells from 16 pregnant women (gestational age: 11 to 24 weeks) were labeled with magnetic beads coupled to anti-CD133 or anti-CD105. Selection of labeled cells was performed using MACS. Resulting CD133+, CD105+, and CD133-/CD105- cell fractions were placed in culture in conditions favoring endothelial cells for 7 days (positive fractions) to 30 days (depleted fractions). Cells from women carrying male fetuses were analyzed by conventional PCR (SRY primers) for detection of male cells. RESULTS: Expansion of cells isolated from all subjects occurred in each of the cell fractions. No PCR products consistent with the presence of male cells were detected in women carrying male fetuses. CONCLUSION: CD133+ and CD105+ cells isolated from maternal blood can be expanded in vitro under endothelial conditions. These cells appear to be of maternal, rather than fetal, origin.

Evaluation of a culture system for enrichment of CD34+ hematopoietic progenitor cells present in maternal blood.

BACKGROUND: Clonogenic expansion of fetal cells in maternal blood is one approach to overcome the very low number of target cells available for prenatal genetic analysis. However, efficient methods of enrichment, culturing conditions and subsequent analysis of fetal cells are lacking. Optimization of this technique requires more detailed evaluation of the composition and distribution of fetal cells that cross the placenta into the maternal circulation. Previous studies by others have shown that fetal blood is rich in CD34+ progenitor cells capable of expansion in cultures supplemented with hematopoeitic growth factors. Moreover, CD34+ fetal cells have been recovered from maternal blood following enrichment. OBJECTIVE: In this study, we examine the type and frequency of hematopoietic progenitor cells detected in maternal (n = 13) and non-pregnant control (n = 4) peripheral blood specimens. METHODS: A methylcellulose-based culture system was used to perform colony assays on CD34+-enriched or non-enriched cells. Overall, a total of 2,249 colonies were scored for colony type among the 17 samples. To determine whether fetal cells were present and expanded, all colonies present in each of the 10 confirmed male-cases (n = 1,525 colonies) were examined either by PCR or FISH. RESULTS: With CD34+-enriched maternal samples, we observed a significantly higher number of burst-forming unit-erythroid (BFU-E) and a reduced number of colony-forming unit-granulocyte, macrophage (CFU-GM) colonies compared to the non-enriched samples. Of 1,067 colonies analyzed by PCR for the amelogenin locus on X and Y, none were found positive for the 250-bp Y-specific sequences. Of 458 colonies tested by FISH for presence of X and Y probe signals, no XY-male cells were detected. CONCLUSION: We conclude that hematopoiesis is enhanced during pregnancy, but the number of fetal progenitor cells is either very low or fail to expand using the enrichment techniques and culturing conditions described in this study. Further development of methods is warranted before considering this approach for prenatal diagnosis.

Intact fetal cells in maternal plasma: are they really there?

Rare fetal cells can be recovered from maternal blood, which suggests that non-invasive prenatal diagnosis is possible. However, recovery and analysis of fetal cells from blood is complex, and sensitivity is low because of the rarity of these cells in the maternal circulation. An alternative strategy, which suggested that intact fetal cells can be found in maternal plasma by use of simple enrichment methods, has been reported. We aimed to replicate this technique. However, five independent laboratories were unable to identify any intact male cells from the plasma of 38 women known to be carrying male fetuses. Although apoptotic intact fetal cells could contribute to the detection of fetal DNA in maternal plasma, we believe that recovery of these cells is difficult and not clinically practical.

Interlaboratory comparison of fetal male DNA detection from common maternal plasma samples by real-time PCR.

BACKGROUND: Analysis of fetal DNA from maternal plasma by PCR offers great potential for noninvasive prenatal genetic diagnosis. To further evaluate this potential, we developed and validated a standard protocol to determine whether fetal DNA sequences could be reproducibly amplified and measured across multiple laboratories in a common set of specimens. METHODS: Each of five participating centers in a National Institute of Child Health and Human Development consortium collected 20 mL of peripheral blood from 20 pregnant women between 10 and 20 weeks of gestation. The plasma fraction was separated according to a common protocol, divided, and frozen in five aliquots. One aliquot was shipped to each participating laboratory, where DNA was extracted according to a standard protocol. All plasma samples (n = 100) were then analyzed blindly for the presence and quantity of total DNA (GAPDH) and male fetal DNA (SRY) by real-time PCR. Genomic DNA was isolated from female and male cells at one center, quantified, and shipped to the others to serve as calibrators for GAPDH and SRY, respectively. RESULTS: The amplification of known quantities of DNA was consistent among all centers. The mean quantity of male DNA amplified from maternal plasma when the fetus was male ranged from 51 to 228 genome equivalents (GE)/mL. Qualitative concordance was found overall among centers. The sensitivity of the assay for detection of male DNA when the fetus was male varied from 31% to 97% among centers. Specificity was more consistent (93-100%) with only four false-positive results obtained across the entire study. CONCLUSIONS: All centers were able to consistently amplify frozen and shipped DNA. The PCR procedure used here is reliable and reproducible. Centers that extracted and amplified more DNA per milliliter of maternal plasma had superior sensitivities of Y chromosome sequence detection. The specificity of the assay was more consistent among centers. A robust and thoroughly optimized protocol for the extraction of DNA from maternal plasma is needed to make testing of fetal DNA in maternal plasma a clinically relevant analytical tool.