Vasculogenesis in complete and partial hydatidiform mole pregnancies studied with CD34 immunohistochemistry

Loss of X Chromosome Inactivation in Androgenetic Complete Hydatidiform Moles With 46, XX Karyotype

Most complete hydatidiform moles (CHMs) showcase an androgenetic nature of the nuclear genome. In the normal female embryo, one of the 2 X chromosomes is inactive. However, the status of X chromosome inactivation (XCI) in androgenetic CHMs remains unknown. Seventy-one androgenetic CHM tissues with the 46, XX karyotype were collected. Seventy-four normal female villi and 74 normal male villi were collected as controls. The expression of XCI markers (XIST, TSIX, and XACT) and an X-linked gene (CDX4) was detected by real-time polymerase chain reaction. Other XCI-associated genes were also examined, including the methylation status of the human androgen receptor gene (HUMARA) by methylation-specific polymerase chain reaction), and the expression of H3K27me3, USP21, and Nanog by Western blot and immunofluorescence, respectively. In addition, 126 CHMs and 63 normal female villous samples were collected for CDX4 immunohistochemical staining. The expression of XIST RNA was significantly lower, and TSIX RNA expression was significantly higher in androgenetic CHMs than that in normal female villi (both P<0.01). The expression of CDX4 mRNA in androgenetic CHMs was elevated compared with that in normal male and normal female villous samples (both P<0.01), and CDX4 protein expression was also higher than that in normal female villous samples (P<0.01). The expression of H3K27me3 was lower in androgenetic CHMs compared with that in normal female villi(P<0.01). The methylation pattern of HUMARA was found lacking in androgenetic CHMs. The expression of Nanog and UPS21 protein in androgenetic CHMs was higher than that in normal villi (both P<0.01). Both X chromosomes are active in androgenetic CHMs with the 46, XX karyotype, and the USP21-Nanog pathway may be involved in the disruption of XCI during this process.

Diagnostic value of glycophorin-A in comparison with P57 immunohistochemical staining method in differentiating complete and partial molar pregnancies

INTRODUCTION

Current histomorphological criteria in distinguishing two subtypes of hydatidiform moles has considerable inter-observer variability and limitations. In this regard, ancillary studies can aid pathologist to obtain an accurate diagnosis. Herein, we evaluated the utility of Glycophorin-A (GLA) in differentiating complete and partial moles.

MATERIALS AND METHODS

In this case-control study, formalin-fixed paraffin-embedded blocks of 47 patients with pathologic diagnosis of complete and 42 partial hydatidiform moles were included and the diagnoses were confirmed by immunohistochemistry (IHC) for P57. Sections from all samples were stained for GLA using IHC method. Using 2 × 2 tables, the sensitivity, specifity, Positive and Negative Predictive Values (PPV and NPV) as well as accuracy of GLA were determined.

RESULTS

Primary pathologic diagnosis was changed in 7.1% and types of hydatidiform mole were specified in 11.9% of the cases after review of the slides and IHC study for P57. NRBCs were found in 52.7% of the PM cases and none of CMs by pathologist in H&E sections. IHC study for GLA revealed positive result in one case of complete moles (2%) and 31 case of partial mole samples (73.8%). It was negative in 98% of the complete mole and 11 (26.2%) of partial mole cases.

DISCUSSION

The results of this study showed a significant association between GLA immunoreactivity and type of molar pregnancy. Diagnostic sensitivity, specificity and accuracy of this marker for discrimination of molar pregnancy were 73.8%, 98% and 86.5%, respectively. Therefore, this marker can be utilized in differentiating partial and complete hydatidiform mole.

Expression of the Carbohydrate Lewis Antigen, Sialyl Lewis A, Sialyl Lewis X, Lewis X, and Lewis Y in the Placental Villi of Patients With Unexplained Miscarriages

Background

Lewis antigens such as Sialyl Lewis A (sLeA), Sialyl Lewis X (sLeX), Lewis X (LeX), and Lewis Y (LeY) are a class of carbohydrate molecules that are known to mediate adhesion between tumor cells and endothelium by interacting with its selectin ligands. However, their potential role in miscarriage remains enigmatic. This study aims to analyze the expression pattern of sLeA, sLeX, LeX, and LeY in the placental villi tissue of patients with a medical history of unexplained miscarriages.

Methods

Paraffin-embedded slides originating from placental tissue were collected from patients experiencing a miscarriage early in their pregnancy (6–13 weeks). Tissues collected from spontaneous (n = 20) and recurrent (n = 15) miscarriages were analyzed using immunohistochemical and immunofluorescent staining. Specimens obtained from legally terminated normal pregnancies were considered as control group (n = 18). Assessment of villous vessel density was performed in another cohort (n = 10 each group) of gestation ages-paired placenta tissue. Protein expression was evaluated with Immunoreactive Score (IRS). Statistical analysis was performed by using Graphpad Prism 8.

Results

Expression of sLeA, sLeX, LeX, and LeY in the syncytiotrophoblast was significantly upregulated in the control group compared with spontaneous and recurrent miscarriage groups. However, no prominent differences between spontaneous and recurrent miscarriage groups were identified. Potential key modulators ST3GAL6 and NEU1 were found to be significantly downregulated in the recurrent miscarriage group and upregulated in the spontaneous group, respectively. Interestingly, LeX and LeY expression was also detected in the endothelial cells of villous vessels in the control group but no significant expression in miscarriage groups. Furthermore, assessment of villous vessel density using CD31 found significantly diminished vessels in all size groups of villi (small villi <200 µm, P = 0.0371; middle villi between 200 and 400 µm, P = 0.0010 and large villi >400 µm, P = 0.0003). Immunofluorescent double staining also indicated the co-localization of LeX/Y and CD31.

Conclusions

The expression of four mentioned carbohydrate Lewis antigens and their potential modulators, ST3GAL6 and NEU1, in the placenta of patients with miscarriages was significantly different from the normal pregnancy. For the first time, their expression pattern in the placenta was illustrated, which might shed light on a novel understanding of Lewis antigens’ role in the pathogenesis of miscarriages.

Hemoglobin Bart hydrops fetalis: A model for studying vascular changes in placental hypoxia

INTRODUCTION

Placental ischemia can be pre-placental (maternal), placental or post-placental (fetal), with corresponding changes in villous vasculature. Hydrops fetalis (HF) resulting from hemoglobin (Hb) Bart disease can serve as a model for intrauterine hypoxia, and placentas from such cases show a distinctive peripheral villous stromal myofibroblastic hypercellularity (PVSH). We hypothesized that Hb Bart disease, which results in profound fetal hypoxia, would lead to placental hypoxia on a post-placental basis.

METHODS

We assessed villous vasculature using computerized morphometry, comparing placentas in 14 Hb Bart HF cases to 18 non-Hb Bart HF cases. Morphometric parameters were matched as closely as possible to those reported in the literature for comparison purposes.

RESULTS

Villous vessels of Hb Bart HF showed significantly increased numbers of vessels (p = 0.001), longer vascular perimeter (p = 0.002), thickening of vascular endothelial layer (p = 0.038) and higher shape coefficient (p = 0.042) indicating a more branching pattern of vessels. In addition, placental villi of Hb Bart HF containing PVSH showed a longer vascular perimeter (p = 0.008) and narrower lumen (p = 0.002), with a higher shape coefficient (p = 0.03), in comparison to villi lacking PVSH.

DISCUSSION

Contrary to expectations, the overall pattern of vascular changes in Hb Bart HF suggested multifactorial hypoxia: pre-placental, on the basis of the marked placentomegaly, compromising blood flow from uterine distention; placental, from hydropic villi causing a generalized diminished intervillous space; and post-placental from the greatly reduced capacity of Hb Bart to extract oxygen from the intervillous space. Standardized vascular morphometry will facilitate comparison between different conditions, for a better understanding of placental hypoxia.

Chorionic villous vascularization related to phenotype and genotype in first trimester miscarriages in a recurrent pregnancy loss cohort

STUDY QUESTION

Is there an association between chorionic villous vascularization, ultrasound findings and corresponding chromosome results in early miscarriage specimens from a cohort of recurrent pregnancy loss patients?

SUMMARY ANSWER

We did not find a significant difference in vascularization scores of chorionic villi between embryonic, yolk sac or empty sac miscarriages, or between euploid and noneuploid miscarriages.

WHAT IS KNOWN ALREADY

At least half of first trimester miscarriages are due to embryopathogenesis associated with chromosome errors and/or major congenital anomalies, resulting in an empty sac, a yolk sac or an embryonic miscarriage. Absent and decreased chorionic villous vascularization is usually present in these pregnancies.

STUDY DESIGN, SIZE, DURATION

For this retrospective study, 60 hematoxylin and eosin slides of miscarriage tissue of less than 10 weeks gestational age were collected from an academic institution. All patients were seen in consultation between July 2004 and October 2009.

PARTICIPANTS, SETTING, METHODS

Chorionic villous vascularization was determined using a previously published classification. The results were validated and compared with the ultrasound findings and corresponding chromosome results.

MAIN RESULTS AND THE ROLE OF CHANCE

There were 53 embryonic miscarriages, 5 yolk sac miscarriages and 2 empty sac miscarriages. Chromosome results were obtained in 59 of the 60 miscarriages; 37.3% were euploid and 62.7% were noneuploid. Validation of the vascularization score between observers was reasonable to good (Kappa 0.47-0.76), and 59% of the cases were classified as avascular. The vascularization score did not differ between euploid or noneuploid miscarriages, or between embryonic, yolk sac or empty sac miscarriages. Avascular villi were seen more frequently in miscarriages trisomic for chromosome 16, when compared with miscarriages with other trisomies (6 out of 7 versus 8 out of 22, P = 0.04).

LIMITATIONS, REASONS FOR CAUTION

Unfortunately, the number of samples in the study was limited.

WIDER IMPLICATIONS OF THE FINDINGS

Avascular villi may indicate abnormal early placentation as a part of embryopathogenesis. Further study is warranted to determine whether a genetic cause can be found to explain these results.

The architecture of first trimester chorionic villous vascularization: a confocal laser scanning microscopical study

BACKGROUND

The aim of this study was to investigate normal chorionic villous vascularization using CD31 immunofluorescence and confocal laser scanning microscopy (CLSM) to elucidate the spatial arrangement in terms of connections between vessels and cords and their branching patterns compared to deficient chorionic villous vascularization in complicated pregnancies.

METHODS

A descriptive morphologic study using CLSM after CD31 immunofluorescence staining of placental biopsies from normal pregnancies (n = 20), complete hydatidiform molar pregnancies (CHMs; n = 3) and empty sacs (n = 3), with a well documented gestational age (GA).

RESULTS

In this three-dimensional study, first trimester chorionic villi were occupied by a complex network of mainly cords with redundant connections as early as 5(+5) weeks GA. With increasing GA cords transform into vessels. From about 9 weeks GA onwards, vascular development is characterized by the presence of two large vessels located centrally and surrounded by and connected to a capillary network. In first trimester CHM and empty sacs, we observed a primitive network of mainly cords.

CONCLUSIONS

This first visualization of the spatio-temporal patterns of blood vessel formation in placental villi is characterized by the development of the vasculosyncytial membrane from a complex network of cords and can be regarded as the placental development before it becomes functional at the end of organogenesis.

Histological classification of chorionic villous vascularization in early pregnancy

BACKGROUND

The objective of the study was to assess the reproducibility of a new classification for early pregnancy chorionic villous vascularization (Grade: I, normal; IIA, mild hypoplasia; IIB, severe hypoplasia and III, avascular) for routine microscopic examination in daily clinical practice.

METHODS

In this observational study, four observers scored first trimester chorionic villous vascularization. Scoring was performed in microscopic slides of chorionic tissue obtained by D&C in 30 patients with early pregnancy loss due to empty sac (n = 10), fetal death (n = 10) and termination of pregnancy (n = 10) using the new classification. Ultrasonographic measurement of trophoblastic thickness (TT) at the implantation site was available in all patients and in a reference group of 100 ongoing singleton pregnancies. The vascularization score could therefore be related to the TT.

RESULTS

The new classification resulted in a good-to-excellent agreement in histological scoring (0.73-0.90) between investigators (kappa 0.64-0.86). TT was not related to either vascularization or pregnancy outcome and only partly to hydropic degeneration.

CONCLUSION

The vascularization scoring system is a simple, valid and effective method for assessment of chorionic villous vascularization. It is helpful in understanding the underlying cause of pregnancy loss, as the classification can distinguish between normal and abnormal embryonic development. We did not find either a relation between TT and pregnancy outcome or between TT and vascularization.