Transient CD15-positive endothelial phenotype in the human placenta correlates with physiological and pathological fetoplacental immaturity

Histopathologic Findings in Large for Gestational Age Placentas and Correlation With CD15 Immunohistochemistry

BACKGROUND

The histopathology and CD15 expression in large for gestational age (LGA) placentas is not well-documented.

METHODS

To analyze this, we utilized 2 separate cohorts of placentas from singleton term deliveries. LGA and appropriate for gestational age (AGA) placentas were compared for major histopathologies including acute and chronic inflammation, maternal and fetal vascular malperfusion, delayed villous maturation (DVM), and villous hypervascularity/chorangiosis. We also examined CD15 immunohistochemistry in LGA and AGA placentas. Stained slides were reviewed blinded to the placental weight. Five random 20× fields were scored semi-quantitatively for CD15 staining of villous capillaries on a scale of 0 to 5 (0 = 0%, 1 = 1%-5%, 2 = 5%-25%, 3 = 25%-50%, 4 = 50%-75%, and 5 = >75%).

RESULTS

In 1 cohort, 1238 LGA and 7908 AGA placentas were identified. Patients with LGA placentas were significantly more likely to have higher birthweight babies, obesity, hypertensive disorders, pre-gestational, and gestational diabetes. Also, LGA placentas had a higher prevalence of fetal vascular malperfusion, DVM, and villous chorangiosis. In other cohort of 75 LGA placentas and 73 AGA controls, the average score of CD15 staining in villous capillaries was significantly higher amongst LGA placentas.

CONCLUSION

We conclude that LGA placentas have increased expression of CD15 in villous capillary endothelium and higher prevalence of FVM, DVM, and villous chorangiosis than AGA placentas.

The role of the placenta in spontaneous preterm labor and delivery with intact membranes

OBJECTIVES

To determine whether placental vascular pathology and impaired placental exchange due to maturational defects are involved in the etiology of spontaneous preterm labor and delivery in cases without histologic acute chorioamnionitis.

METHODS

This was a retrospective, observational study. Cases included pregnancies that resulted in spontaneous preterm labor and delivery (<37 weeks), whereas uncomplicated pregnancies that delivered fetuses at term (≥37-42 weeks of gestation) were selected as controls. Placental histological diagnoses were classified into three groups: lesions of maternal vascular malperfusion, lesions of fetal vascular malperfusion, and placental microvasculopathy, and the frequency of each type of lesion in cases and controls was compared. Moreover, we specifically searched for villous maturational abnormalities in cases and controls. Doppler velocimetry of the umbilical and uterine arteries were performed in a subset of patients.

RESULTS

There were 184 cases and 2471 controls, of which 95 and 1178 had Doppler studies, respectively. The frequency of lesions of maternal vascular malperfusion was greater in the placentas of patients with preterm labor than in the control group [14.1% (26/184) vs. 8.8% (217/2471) (p=0.023)]. Disorders of villous maturation were more frequent in the group with preterm labor than in the control group: 41.1% (39/95) [delayed villous maturation in 31.6% (30/95) vs. 2.5% (13/519) in controls and accelerated villous maturation in 9.5% (9/95) vs. none in controls].

CONCLUSIONS

Maturational defects of placental villi were associated with approximately 41% of cases of unexplained spontaneous preterm labor and delivery without acute inflammatory lesions of the placenta and with delivery of appropriate-for-gestational-age fetuses.

Early Pregnancy Exposure to Ambient Air Pollution among Late-Onset Preeclamptic Cases Is Associated with Placental DNA Hypomethylation of Specific Genes and Slower Placental Maturation

Exposure to ambient air pollution during pregnancy has been associated with an increased risk of preeclampsia (PE). Some suggested mechanisms behind this association are changes in placental DNA methylation and gene expression. The objective of this study was to identify how early pregnancy exposure to ambient nitrogen oxides (NO_x) among PE cases and normotensive controls influence DNA methylation (EPIC array) and gene expression (RNA-seq). The study included placentas from 111 women (29 PE cases/82 controls) in Scania, Sweden. First-trimester NO_x exposure was assessed at the participants’ residence using a dispersion model and categorized via median split into high or low NO_x. Placental gestational epigenetic age was derived from the DNA methylation data. We identified six differentially methylated positions (DMPs, q < 0.05) comparing controls with low NO_x vs. cases with high NO_x and 14 DMPs comparing cases and controls with high NO_x. Placentas with female fetuses showed more DMPs (N = 309) than male-derived placentas (N = 1). Placentas from PE cases with high NO_x demonstrated gestational age deceleration compared to controls with low NO_x (p = 0.034). No differentially expressed genes (DEGs, q < 0.05) were found. In conclusion, early pregnancy exposure to NO_x affected placental DNA methylation in PE, resulting in placental immaturity and showing sexual dimorphism.

Disorders of placental villous maturation are present in one-third of cases with spontaneous preterm labor

OBJECTIVES

Spontaneous preterm labor is an obstetrical syndrome accounting for approximately 65-70% of preterm births, the latter being the most frequent cause of neonatal death and the second most frequent cause of death in children less than five years of age worldwide. The purpose of this study was to determine and compare to uncomplicated pregnancies (1) the frequency of placental disorders of villous maturation in spontaneous preterm labor; (2) the frequency of other placental morphologic characteristics associated with the preterm labor syndrome; and (3) the distribution of these lesions according to gestational age at delivery and their severity.

METHODS

A case-control study of singleton pregnant women was conducted that included (1) uncomplicated pregnancies (controls, n=944) and (2) pregnancies with spontaneous preterm labor (cases, n=438). All placentas underwent histopathologic examination. Patients with chronic maternal diseases (e.g., chronic hypertension, diabetes mellitus, renal disease, thyroid disease, asthma, autoimmune disease, and coagulopathies), fetal malformations, chromosomal abnormalities, multifetal gestation, preeclampsia, eclampsia, preterm prelabor rupture of the fetal membranes, gestational hypertension, gestational diabetes mellitus, and HELLP (hemolysis, elevated liver enzymes and low platelet count) syndrome were excluded from the study.

RESULTS

Compared to the controls, the most prevalent placental lesions among the cases were the disorders of villous maturation (31.8% [106/333] including delayed villous maturation 18.6% [62/333] vs. 1.4% [6/442], q<0.0001, prevalence ratio 13.7; and accelerated villous maturation 13.2% [44/333] vs. 0% [0/442], q<0.001). Other lesions in decreasing order of prevalence included hypercapillarized villi (15.6% [68/435] vs. 3.5% [33/938], q<0.001, prevalence ratio 4.4); nucleated red blood cells (1.1% [5/437] vs. 0% [0/938], q<0.01); chronic inflammatory lesions (47.9% [210/438] vs. 29.9% [282/944], q<0.0001, prevalence ratio 1.6); fetal inflammatory response (30.1% [132/438] vs. 23.2% [219/944], q<0.05, prevalence ratio 1.3); maternal inflammatory response (45.5% [195/438] vs. 36.1% [341/944], q<0.01, prevalence ratio 1.2); and maternal vascular malperfusion (44.5% [195/438] vs. 35.7% [337/944], q<0.01, prevalence ratio 1.2). Accelerated villous maturation did not show gestational age-dependent association with any other placental lesion while delayed villous maturation showed a gestational age-dependent association with acute placental inflammation (q-value=0.005).

CONCLUSIONS

Disorders of villous maturation are present in nearly one-third of the cases of spontaneous preterm labor.

CD15 immunostaining improves placental diagnosis of fetal hypoxia

INTRODUCTION

Fetal hypoxic events with unclear predictive value are a common indication for placenta examination. We evaluated whether the use of CD15 immunostaining can improve the assessment of severity and duration of fetal hypoxia.

METHODS

We compared placentas (37-42 gestational weeks) from stillborns/newborns with birth asphyxia (BA) and non-hypoxic newborns. Placental findings were studied in following groups: (1) acute BA (n = 11) due to placental abruption, (2) non-acute BA (n = 121) due to non-acute conditions, (3) non-BA (n = 46) in pregnancies with preeclampsia and gestational diabetes, and (4) controls (n = 30).

RESULTS

A high expression of CD15 in feto-placental resistance vessels (FRVs) was present in non-acute BA (95.9%), but absent in acute BA, non-BA and controls (p < 0.0001). Furthermore, we found no causal relationship of high expression of CD15 in FRVs to coexisting placental conditions, including severity and mechanisms/patterns of placental injury, fetal erythroblastosis, and maternal conditions. According to a multivariate analysis, only a high expression of CD15 in FRVs was independently associated with severe non-acute fetal hypoxia ([OR] = 15.52; 95% [CI] = 5.92-40.67).

DISCUSSION

We have defined a characteristic pattern of CD15 expression in FRVs that allows to interpret various clinical/placental conditions with respect to fetal hypoxia, with an improved predictability compared to conventional analyses. This approach represents a novel diagnostic strategy for placenta examination, which could indirectly assess severity and duration of intrauterine hypoxia in a heterogeneous population of newborns.

Disorders of placental villous maturation in fetal death

Objective The aims of this study were to ascertain the frequency of disorders of villous maturation in fetal death and to also delineate other placental histopathologic lesions in fetal death. Methods This was a retrospective observational cohort study of fetal deaths occurring among women between January 2004 and January 2016 at Hutzel Women's Hospital, Detroit, MI, USA. Cases comprised fetuses with death beyond 20 weeks' gestation. Fetal deaths with congenital anomalies and multiple gestations were excluded. Controls included pregnant women without medical/obstetrical complications and delivered singleton, term (37-42 weeks) neonate with 5-min Apgar score ≥7 and birthweight between the 10th and 90th percentiles. Results Ninety-two percent (132/143) of placentas with fetal death showed placental histologic lesions. Fetal deaths were associated with (1) higher frequency of disorders of villous maturation [44.0% (64/143) vs. 1.0% (4/405), P < 0.0001, prevalence ratio, 44.6; delayed villous maturation, 22% (31/143); accelerated villous maturation, 20% (28/143); and maturation arrest, 4% (5/143)]; (2) higher frequency of maternal vascular malperfusion lesions [75.5% (108/143) vs. 35.7% (337/944), P < 0.0001, prevalence ratio, 2.1] and fetal vascular malperfusion lesions [88.1% (126/143) vs. 19.7% (186/944), P < 0.0001, prevalence ratio, 4.5]; (3) higher frequency of placental histologic patterns suggestive of hypoxia [59.0% (85/143) vs. 9.3% (82/942), P < 0.0001, prevalence ratio, 6.8]; and (4) higher frequency of chronic inflammatory lesions [53.1% (76/143) vs. 29.9% (282/944), P < 0.001, prevalence ratio 1.8]. Conclusion This study demonstrates that placentas of women with fetal death were 44 times more likely to present disorders of villous maturation compared to placentas of those with normal pregnancy. This suggests that the burden of placental disorders of villous maturation lesions is substantial.

Discordancy for a Villous Maturation Defect in a Dizygotic Twin Placenta

Background: Dizygotic twin pregnancies with discordant manifestation of abnormalities with unclear etiology are of interest because they arise in the same environment. Case report: We present a dizygotic third trimester twin placenta with discordant villous maturation, one placenta lacking developed syncytiocapillary membranes. The twins were eutrophic with no perinatal or postnatal complications. Conclusions: Discordant manifestation of villous maturation in dizygotic twin placentas could be a hint for a genetic rather than an environmental etiology. Villous maturation defect may be underrecognized and has been associated with perinatal morbidity and stillbirth in the late third trimester. Proper recognition is important because of the increased recurrence risk of villous dysmaturity.

Mechanisms of death in structurally normal stillbirths

Objectives To investigate mechanisms of in utero death in normally formed fetuses by measuring amniotic fluid (AF) biomarkers for hypoxia (erythropoietin [EPO]), myocardial damage (cardiac troponin I [cTnI]) and brain injury (glial fibrillary acidic protein [GFAP]), correlated with risk factors for fetal death and placental histopathology. Methods This retrospective, observational cohort study included intrauterine deaths with transabdominal amniocentesis prior to induction of labor. Women with a normal pregnancy and an indicated amniocentesis at term were randomly selected as controls. AF was assayed for EPO, cTnI and GFAP using commercial immunoassays. Placental histopathology was reviewed, and CD15-immunohistochemistry was used. Analyte concentrations >90th centile for controls were considered "raised". Raised AF EPO, AF cTnI and AF GFAP concentrations were considered evidence of hypoxia, myocardial and brain injury, respectively. Results There were 60 cases and 60 controls. Hypoxia was present in 88% (53/60), myocardial damage in 70% (42/60) and brain injury in 45% (27/60) of fetal deaths. Hypoxic fetuses had evidence of myocardial injury, brain injury or both in 77% (41/53), 49% (26/53) and 13% (7/53) of cases, respectively. Histopathological evidence for placental dysfunction was found in 74% (43/58) of these cases. Conclusion Hypoxia, secondary to placental dysfunction, was found to be the mechanism of death in the majority of fetal deaths among structurally normal fetuses. Ninety-one percent of hypoxic fetal deaths sustained brain, myocardial or both brain and myocardial injuries in utero. Hypoxic myocardial injury was an attributable mechanism of death in 70% of the cases. Non-hypoxic cases may be caused by cardiac arrhythmia secondary to a cardiac conduction defect.

Immaturity for gestational age of microvasculature and placental barrier in term placentas with high weight

OBJECTIVE

Villous immaturity for gestational age is a multifactorial developmental deviation associated with unexpected placental insufficiency, fetal hypoxia and term fetal death. In our previous work we have shown that immature CD15+/CD31+/CD34+ endothelial cells were an important indicator of placental villous immaturity and chronic insufficiency. The aim of this study was to perform a comparative analysis of CD15-marked immaturity in the vessel walls between normal and pathological term placentas of clinically and structurally heterogenous groups with normal, low and high weight.

STUDY DESIGN

165 clinically normal and pathological placentas of gestational age 39-42 with normal weight (25-75 percentile), low weight (<10 percentile) and high weight (>90 percentile) were structurally and immunohistochemically analyzed. Excluded were placentas with a severe form of placental insufficiency associated with intrauterine fetal death, low APGAR-score, genetic and chromosomal diseases or placental inflammations. The distribution patterns of CD15, CD31 and CD34 were assessed separately in the macrovasculature, microvasculature and placental barrier (PB) - associated capillaries.

RESULTS

All placental groups with normal weight, low weight and high weight include normal, accelerated villous maturation or villous immaturity independent of their weight. However, a significant increase of immature CD15+/CD31+/CD34+ endothelial cells was detected in microvasculature and PB -associated capillaries in high weight-placentas (63.5%/52.2%), compared to those of normal weight (13.8%/8.2%) and low weight (16.1%/17.8%). The distribution of macrovascular immature CD15+/CD31+/CD34+ endothelial cells did not show such marked differences.

CONCLUSION

We have identified the immaturity of microvasculature and PB -associated capillaries with a pathological persistency of immature CD15+/CD31+/CD34+ endothelial cells and a reduction of terminally differentiated CD15-/CD31+/CD34+ endothelial cells in a structurally and clinically heterogeneous group of high weight-placentas. We assume that immaturity of placental vessels are part of prenatal adaptational processes that can be recruited in different emergency situations and may provide potential targets of therapeutic correction of placental growth and chronic insufficiency. We therefore recommend the use of CD15-based immunophenotyping as a method to identify latent unfavorable conditions of fetal development in the intrauterine life and individual risk of disease in the postnatal period.

The embryo-placental CD15-positive "vasculogenic zones" as a source of propranolol-sensitive pediatric vascular tumors

OBJECTIVE

Propranolol-induced involution is a unique biological feature of some pediatric vascular tumors, for instance infantile hemangioma (IH), cerebral cavernoma or chorioangioma. Currently, the cellular origin of these distinct tumors is unclear. In this study, we tested the hypothesis that propranolol-responsive vascular tumors are derived from common vessel-forming CD15 + progenitor cells which occur in early gestation. The aim of this study was to identify the tumor-relevant CD15 + progenitors at the early stages of embryo-placental development.

MATERIALS AND METHODS

Human embryo-placental units of 4-8 weeks gestation and pediatric vascular tumors were tested for expression of the tumor-relevant markers CD15, CD31 and CD34.

RESULTS

Placental vessel-forming progenitors were characterized by immunostaining for CD15, CD31, and CD34. In embryonic tissue, a discontinuous CD15+/CD31+/CD34 + progenitors was detected in immature vessels of the skin, neural tube, spinal and cerebral meninges. Similarly, vessels in IH and chorioangioma exhibited a co-expression of CD15, CD31, and CD34. In contrast, the majority of embryonic vessels presented a CD31+/CD34+, but CD15-negative immunophenotypic pattern.

DISCUSSION

Our results suggest the existence of a CD15+ "vasculogenic zones" in the embryo-placental unit as well as in IH and chorioangioma. A site-specific correlation between normal embryo-placental and tumoral vessel-forming CD15 + progenitors was demonstrated.

CONCLUSION

Hence, site- and stage-specific CD15 + progenitors of vascular wall could be considered as propronalol-sensitive targets and source of pre- and postnatal vascular tumors. We propose, that the CD15+ "vasculogenic zones" are a site-specific reserve of multi-lineage progenitors that could be recruited in pre- and postnatal emergency situations.

CD15 - a new marker of pathological villous immaturity of the term placenta

INTRODUCTION

Idiopathic immaturity is one of the main reasons for latent placental insufficiency and antenatal hypoxia. Postnatal identification of the immature placental phenotype may help early stratification of a heterogeneous population of newborns and individually identify risk of disease in the immediate postnatal life. The aim of the study was to determine the relevant diagnostic markers associated with pathological placental immaturity.

METHODS

111 tissue samples from normal and pathological term placentas with persisting villous immaturity comprised the comparative immunohistochemical study (CD15, CD34). Positive immunohistochemical reactions were quantitatively assessed in the chorionic plate and vessels of the villi of different histological type.

RESULTS

We have shown that pathological villous immaturity is attended by significantly increased CD15-expression in the macro- and microvascular endothelium compared with the normal placenta. CD34-expression was not different from that in normal placentas.

DISCUSSION

This paper documents the correlation of CD15+ endothelium in the macrovascular fetoplacental vessels with a severe form of villous immaturity associated with fetal hypoxia/asphyxia and erythroblastosis. Increased CD15-expression only in the microvascular segment of the fetoplacental vessels correlated with moderate villous immaturity and was associated with GDM, idiopathic fetal macrosomia and nonspecific chronic villitis.

CONCLUSION

We propose that "immature" CD15+ endothelium is an important diagnostic marker of persisting villous immaturity and chronic placental dysfunction. The level of CD15 expression in the macro- and microvasculature reflects the degree of pathological placental villous immaturity.