Role of the mechanotransductor PIEZO1 in megakaryocyte differentiation.

From haematopoietic stem cells to megakaryocytes (Mks), cells undergo various mechanical forces that affect Mk differentiation, maturation and proplatelet formation. The mechanotransductor PIEZO1 appears to be a natural candidate for sensing these mechanical forces and regulating megakaryopoiesis and thrombopoiesis. Gain-of-function mutations of PIEZO1 cause hereditary xerocytosis, a haemolytic anaemia associated with thrombotic events. If some functions of PIEZO1 have been reported in platelets, few data exist on PIEZO1 role in megakaryopoiesis. To address this subject, we used an in vitro model of Mk differentiation from CD34+ cells and studied step-by-step the effects of PIEZO1 activation by the chemical activator YODA1 during Mk differentiation and maturation. We report that PIEZO1 activation by 4 µM YODA1 at early stages of culture induced cytosolic calcium ion influx and reduced cell maturation. Indeed, CD41+CD42+ numbers were reduced by around 1.5-fold, with no effects on proliferation. At later stages of Mk differentiation, PIEZO1 activation promoted endomitosis and proplatelet formation that was reversed by PIEZO1 gene invalidation with a shRNA-PIEZO1. Same observations on endomitosis were reproduced in HEL cells induced into Mks by PMA and treated with YODA1. We provide for the first time results suggesting a dual role of PIEZO1 mechanotransductor during megakaryopoiesis.

Gain-of-function mutations in PIEZO1 directly impair hepatic iron metabolism via the inhibition of the BMP/SMADs pathway.

Dehydrated hereditary stomatocytosis (DHS), or xerocytosis, is an autosomal dominant hemolytic anemia. Most patients with DHS carry mutations in the PIEZO1 gene encoding a mechanosensitive cation channel. We here demonstrate that patients with DHS have low levels of hepcidin and only a slight increase of ERFE, the erythroid negative regulator of hepcidin. We demonstrated that at the physiological level, PIEZO1 activation induced Ca2+ influx and suppression of HAMP expression in primary hepatocytes. In two hepatic cellular models expressing PIEZO1 WT and two PIEZO1 gain-of-function mutants (R2456H and R2488Q), we highlight altered expression of a few genes/proteins involved in iron metabolism. Mutant cells showed increased intracellular Ca2+ compared to WT, which was correlated to increased phosphorylation of ERK1/2, inhibition of the BMP-SMADs pathway, and suppression of HAMP transcription. Moreover, the HuH7 cells, treated with PD0325901, a potent inhibitor of ERK1/2 phosphorylation, reduced the phosphorylation of ERK1/2 with the consequent increased phosphorylation of SMAD1/5/8, confirming the link between the two pathways. Another "proof of concept" for the mechanism that links PIEZO1 to HAMP regulation was obtained by mimicking PIEZO1 activation by cell Ca2+ overload, by the Ca2+ ionophore A23187. There was strong down-regulation of HAMP gene expression after this Ca2+ overload. Finally, the inhibition of PIEZO1 by GsMTx4 leads to phenotype rescue. This is the first demonstration of a direct link between PIEZO1 and iron metabolism, which defines the channel as a new hepatic iron metabolism regulator and as a possible therapeutic target of iron overload in DHS and other iron-loading anemias.

Biological importance of podoplanin expression in chorionic villous stromal cells and its relationship to placental pathologies.

Podoplanin, a reliable marker of lymphatic endothelium, is a mucin-type transmembrane protein. Although the human placenta is devoid of a lymphatic system, chorionic villous stromal (CVS) cells express podoplanin. In this study, the pattern of podoplanin expression in normal and pathological placental tissues and the biological role of podoplanin were investigated. In total, 198 placental tissues belonging to 184 patients, seen at the Department of Pathology of Bulent Ecevit University Education and Research Hospital, Zonguldak, Turkey, were evaluated histopathologically and determined to meet the study criteria. The tissues were assigned to control, cisternal placental disorders, inflammation and hypoxic-ischemic pathology groups. Podoplanin expression in CVS cells was graded from 0 to 3 depending on the staining intensity, as determined by an immunohistochemical evaluation of chorionic villi in the most intensively stained tissue region. Podoplanin levels in control CVS cells increased in parallel with placental maturation, whereas in molar pregnancies podoplanin expression was lower than in control tissues. In the acute placental inflammation group, podoplanin immunoreactivity was similar to that in the control group, whereas in the preeclampsia group, podoplanin expression was higher than in all other groups. Our study showed an increase in podoplanin expression in CVS cells during pregnancy. In preeclamptic patients, the increase in podoplanin expression may be a response to hypoxic-ischemic conditions, whereas in molar pregnancies the decrease in podoplanin levels may cause villous swelling by disrupting intercellular fluid homeostasis.

hCALCRL mutation causes autosomal recessive nonimmune hydrops fetalis with lymphatic dysplasia.

We report the first case of nonimmune hydrops fetalis (NIHF) associated with a recessive, in-frame deletion of V205 in the G protein-coupled receptor, Calcitonin Receptor-Like Receptor (hCALCRL). Homozygosity results in fetal demise from hydrops fetalis, while heterozygosity in females is associated with spontaneous miscarriage and subfertility. Using molecular dynamic modeling and in vitro biochemical assays, we show that the hCLR(V205del) mutant results in misfolding of the first extracellular loop, reducing association with its requisite receptor chaperone, receptor activity modifying protein (RAMP), translocation to the plasma membrane and signaling. Using three independent genetic mouse models we establish that the adrenomedullin-CLR-RAMP2 axis is both necessary and sufficient for driving lymphatic vascular proliferation. Genetic ablation of either lymphatic endothelial Calcrl or nonendothelial Ramp2 leads to severe NIHF with embryonic demise and placental pathologies, similar to that observed in humans. Our results highlight a novel candidate gene for human congenital NIHF and provide structure-function insights of this signaling axis for human physiology.

Inherited or acquired modifiers of iron status may dramatically affect the phenotype in dehydrated hereditary stomatocytosis.

Severe iron overload is frequent in dehydrated hereditary stomatocytosis (DHSt) despite well-compensated hemolysis and no or little transfusion requirement. We investigated 4 patients with proven DHSt, in whom the degree of hemolysis was closely related to iron status. Genetic modifiers increasing iron stores (HFE:pCys282Tyr, HAMP:c-153C>T mutations) were accompanied with high liver iron concentrations and increased hemolysis, whereas therapeutic phlebotomies alleviated the hemolytic phenotype. There were no manifestations of hemolysis in one patient with low iron stores. Hemolysis reappeared when iron supplementation was given. The search for genetic or acquired modifiers of iron status and the modulation of iron stores may help in the management of these patients.

EPHB4 kinase-inactivating mutations cause autosomal dominant lymphatic-related hydrops fetalis.

Hydrops fetalis describes fluid accumulation in at least 2 fetal compartments, including abdominal cavities, pleura, and pericardium, or in body tissue. The majority of hydrops fetalis cases are nonimmune conditions that present with generalized edema of the fetus, and approximately 15% of these nonimmune cases result from a lymphatic abnormality. Here, we have identified an autosomal dominant, inherited form of lymphatic-related (nonimmune) hydrops fetalis (LRHF). Independent exome sequencing projects on 2 families with a history of in utero and neonatal deaths associated with nonimmune hydrops fetalis uncovered 2 heterozygous missense variants in the gene encoding Eph receptor B4 (EPHB4). Biochemical analysis determined that the mutant EPHB4 proteins are devoid of tyrosine kinase activity, indicating that loss of EPHB4 signaling contributes to LRHF pathogenesis. Further, inactivation of Ephb4 in lymphatic endothelial cells of developing mouse embryos led to defective lymphovenous valve formation and consequent subcutaneous edema. Together, these findings identify EPHB4 as a critical regulator of early lymphatic vascular development and demonstrate that mutations in the gene can cause an autosomal dominant form of LRHF that is associated with a high mortality rate.

Impaired PIEZO1 function in patients with a novel autosomal recessive congenital lymphatic dysplasia.

Piezo1 ion channels are mediators of mechanotransduction in several cell types including the vascular endothelium, renal tubular cells and erythrocytes. Gain-of-function mutations in PIEZO1 cause an autosomal dominant haemolytic anaemia in humans called dehydrated hereditary stomatocytosis. However, the phenotypic consequence of PIEZO1 loss of function in humans has not previously been documented. Here we discover a novel role of this channel in the lymphatic system. Through whole-exome sequencing, we identify biallelic mutations in PIEZO1 (a splicing variant leading to early truncation and a non-synonymous missense variant) in a pair of siblings affected with persistent lymphoedema caused by congenital lymphatic dysplasia. Analysis of patients' erythrocytes as well as studies in a heterologous system reveal greatly attenuated PIEZO1 function in affected alleles. Our results delineate a novel clinical category of PIEZO1-associated hereditary lymphoedema.

[Clinicopathologic features of fetal nuchal cystic hygroma: report of 40 cases].

OBJECTIVE: To study the pathogenesis, pathologic features and prognosis of fetal nuchal cystic hygroma. METHODS: Forty autopsied cases of fetal nuchal cystic hygroma were collected during January 2003 to December 2012. The clinical history, pathologic changes and immunohistochemical (EnVision method) findings were reviewed, and the pathogenesis and pathologic characteristics were analyzed. RESULTS: Of the 40 cases, 16 (40.0%) showed single malformation and 24 (60.0%) were associated with multiple malformations in other organs and/or systems.Nineteen cases were septated and 21 were not. The associated malformations occurred in the respiratory system, skeletal system and urinary system.In the cases of combined malformations of umbilical cord, 3 were single umbilical artery malformations and 1 was torsion and stricture of umbilical cord.Four cases had chromosomal analysis, and all were trisomy-21. CONCLUSIONS: Fetal nuchal cystic hygroma is a rare disease. The etiology is unknown, but it is not neoplastic.Lymphangioma is divided into 3 types:capillary lymphangioma, cavernous lymphangioma and cystic hygroma according to their expansile growth pattern. The overall prognosis is determined by any co-existing chromosomal anomalies, associated malformations and the time of diagnosis of the cystic hygroma.

Are alanine, cysteine, glycine and valine amino acids the cause of non-immune hydrops fetalis?

Our objective was to measure amniotic fluid amino acid concentrations in pregnant women diagnosed as having fetuses with non immune hydrops fetalis in the second trimester of pregnancy. Twenty-three pregnant women who had fetuses with non immune hydrops fetalis detected by ultrasonography (non immune hydrops fetalis group) in the second trimester and 19 women who had healthy fetuses (control group) were enrolled in the study. Amniotic fluid was obtained by amniocentesis. The chromosomal analysis of the study and control groups was normal. Levels of free amino acids were measured in amniotic fluid samples using EZ: fast kits (EZ: fast GC/FID free (physiological) amino acid kit) by gas chromatography (Focus GC Al 3000 Thermo Finnigan analyzer). The mean levels of alanine, cysteine, glycine and valine amino acids were found to be significantly higher in fetuses with non immune hydrops fetalis than in the control group (p<0.05). The detection of significantly higher amino acid concentrations in the amniotic fluid of fetuses with a non immune hydrops fetalis in healthy fetuses suggests loss of amino acids from the fetus through capillary permeability or/and the lymphatic system through the amniotic fluid may contribute to the etiology of non-immune hydrops fetalis.

Piezo1: properties of a cation selective mechanical channel.

Piezo ion channels have been found to be essential for mechanical responses in cells. These channels were first shown to exist in Neuro2A cells, and the gene was identified by siRNAs that diminished the mechanical response. Piezo channels are approximately 2500 amino acids long, have between 24-32 transmembrane regions, and appear to assemble into tetramers and require no other proteins for activity. They have a reversal potential around 0 mV and show voltage dependent inactivation. The channel is constitutively active in liposomes, indicating that no cytoskeletal elements are required. Heterologous expression of the Piezo protein can create mechanical sensitivity in otherwise insensitive cells.   Piezo1 currents in outside-out patches were blocked by the extracellular MSC inhibitor peptide GsMTx4. Both enantiomeric forms of GsMTx4 inhibited channel activity in a manner similar to endogenous mechanical channels. Piezo1 can adopt a tonic (non-inactivating) form with repeated stimulation. The transition to the non-inactivating form generally occurs in large groups of channels, indicating that the channels exist in domains, and once the domain is compromised, the members simultaneously adopt new properties. Piezo proteins are associated with physiological responses in cells, such as the reaction to noxious stimulus of Drosophila larvae. Recent work measuring cell crowding, shows that Piezo1 is essential for the removal of extra cells without apoptosis. Piezo1 mutations have also been linked to the pathological response of red blood cells in a genetic disease called Xerocytosis. These finding suggest that Piezo1 is a key player in cells' responses to mechanical stimuli.

Immunohistochemical studies in a hydroptic fetus with pulmonary lymphangiectasia and trisomy 21.

This case report presents a hydroptic trisomy 21 fetus affected by lymphatic dysplasia with no other malformations. Our studies using CD31, CD34, smooth muscle actin, desmin, and D2-40 antibodies immunohistochemistry confirm the diagnosis of severe pulmonary lymphangiectasia associated with lymphangiectasia ih the mediastinum and small bowel.

Fetal gonadoblastoid testicular dysplasia: a focal failure of testicular development.

Fetal gonadoblastoid testicular dysplasia (FGTD) is an extremely rare lesion, which, in its original description, appeared in association with hydrops fetalis and other malformations. Its phenotype strongly resembles gonadoblastoma, although in contrast with that rare tumor, FGTD is not associated with the intersexual states or gonadal dysgenesis that accompany such neoplasm. Two reports described an association of FGTD and a morphologically similar lesion with Walker-Warburg syndrome. However, we have not confirmed such an observation, although a nonspecific muscle disorder was found in one of the examples we describe in this article. Here we study 2 additional cases, providing a detailed topographical, histomorphological, and immunophenotypical analysis. A review of all 5 previously described cases is conducted. The features of this lesion support the notion that a focal defect in testicular development is its most likely pathogenesis.

HEM dysplasia and ichthyosis are likely laminopathies and not due to 3beta-hydroxysterol Delta14-reductase deficiency.

Mutations of the lamin B receptor (LBR) have been shown to cause HEM dysplasia in humans and ichthyosis in mice. LBR is a bifunctional protein with both a lamin B binding and a sterol Delta(14)-reductase domain. It previously has been proposed that LBR is the primary sterol Delta(14)-reductase and that HEM dysplasia and ichthyosis are inborn errors of cholesterol synthesis. However, DHCR14 also encodes a sterol Delta(14)-reductase and could provide enzymatic redundancy with respect to cholesterol synthesis. To test the hypothesis that LBR and DHCR14 both function as sterol Delta(14)-reductases, we obtained ichthyosis mice (Lbr(-/-)) and disrupted Dhcr14. Heterozygous Lbr and Dhcr14 mice were intercrossed to test for a digenic phenotype. Lbr(-/-), Dhcr14(Delta4-7/Delta4-7) and Lbr(+/-):Dhcr14(Delta4-7/Delta4-7) mutant mice have distinct physical and biochemical phenotypes. Dhcr14(Delta4-7/Delta4-7) mice are essentially normal, whereas Lbr(+/-):Dhcr14(Delta4-7/Delta4-7) mice are growth retarded and neurologically abnormal. Neither of these mutants resembles the ichthyosis mouse and biochemically, no sterol abnormalities were detected in either liver or kidney tissue. In contrast, relatively small transient elevations of Delta(14)-sterols were observed in Lbr(-/-) and Dhcr14(Delta4-7/Delta4-7) brain tissue, and marked elevations were seen in Lbr(+/-):Dhcr14(Delta4-7/Delta4-7) brain. Pathological evaluation demonstrated vacuolation and swelling of the myelin sheaths in the spinal cord of Lbr(+/-):Dhcr14(Delta4-7/Delta4-7) mice consistent with a demyelinating process. This was not observed in either Lbr(-/-) or Dhcr14 (Delta4-7/Delta4-7) mice. Our data support the conclusions that LBR and DHCR14 provide substantial enzymatic redundancy with respect to cholesterol synthesis and that HEM dysplasia and ichthyosis are laminopathies rather than inborn errors of cholesterol synthesis.

A role of the anti-angiogenic factor sVEGFR-1 in the 'mirror syndrome' (Ballantyne's syndrome).

BACKGROUND: 'Mirror syndrome' (Ballantyne's syndrome) refers to the association of fetal hydrops with placentomegaly and severe maternal edema. Preeclampsia occurs in approximately 50% of these cases. Soluble vascular endothelial growth factor receptor-1 (sVEGFR-1), an anti-angiogenic factor, has been implicated in the pathophysiology of preeclampsia (PE). OBJECTIVE: The objective of this study was to determine if the maternal plasma concentration of sVEGFR-1 is elevated in patients with mirror syndrome. STUDY DESIGN: This case-control study included patients with uncomplicated pregnancies (n = 40) and those with mirror syndrome (n = 4) matched for gestational age. Mirror syndrome was defined as fetal hydrops and severe maternal edema. Maternal plasma sVEGFR-1 concentrations were determined using specific enzyme-linked immunosorbent assays. Immunohistochemistry of sVEGFR-1 on villous trophoblasts was also performed in samples from one patient with mirror syndrome and compared with those from a patient with spontaneous preterm delivery matched for gestational age. Non-parametric statistics were used for analysis (p < 0.05). RESULTS: (1) The median maternal plasma concentration of sVEGFR-1 was significantly higher in patients with mirror syndrome than in the control group (median: 3974 pg/mL, range: 3083-10 780 vs. median: 824 pg/mL, range: 260-4712, respectively; p < 0.001). (2) All patients with mirror syndrome had sVEGFR-1 concentrations above the 95th percentile for gestational age. Syncytiotrophoblast, especially syncytial knots, showed strong staining with antibodies against sVEGFR-1 in placental samples from the patient with mirror syndrome, but not in those from the patient with spontaneous preterm delivery. CONCLUSION: High maternal plasma concentrations of sVEGFR-1 were observed in mirror syndrome. We propose that this anti-angiogenic factor may participate in the pathophysiology of this syndrome. Thus, maternal plasma determination of sVEGFR-1 may help to identify the hydropic fetus that places the mother at risk for preeclampsia.

Hydrops fetalis, cardiovascular defects, and embryonic lethality in mice lacking the calcitonin receptor-like receptor gene.

Adrenomedullin (AM) is a multifunctional peptide vasodilator that is essential for life. To date, numerous in vitro studies have suggested that AM can mediate its biological effects through at least three different receptors. To determine the in vivo importance of the most likely candidate receptor, calcitonin receptor-like receptor, a gene-targeted knockout model of the gene was generated. Mice heterozygous for the targeted Calcrl allele appear normal, survive to adulthood, and reproduce. However, heterozygote matings fail to produce viable Calcrl-/- pups, demonstrating that Calcrl is essential for survival. Timed matings confirmed that Calcrl-/- embryos die between embryonic day 13.5 (E13.5) and E14.5 of gestation. The Calcrl-/- embryos exhibit extreme hydrops fetalis and cardiovascular defects, including thin vascular smooth muscle walls and small, disorganized hearts remarkably similar to the previously characterized AM-/- phenotype. In vivo assays of cellular proliferation and apoptosis in the hearts and vasculature of Calcrl-/- and AM-/- embryos support the concept that AM signaling is a crucial mediator of cardiovascular development. The Calcrl gene targeted mice provide the first in vivo genetic evidence that CLR functions as an AM receptor during embryonic development.

Increased expression of vascular endothelial growth factor in cardiac structures of fetus with hydrops as compared to nonhydropic controls.

OBJECTIVE: The hypothesis that severe fetal hydrops is caused by an excess of vascular endothelial growth factor (VEGF), mainly produced in the fetal heart, is tested. METHODS: Immunohistochemical VEGF-stained postmortem biopsies from the right ventricle and right atrium of 8 hydropic fetuses were compared to those of 8 nonhydropic fetuses. The endocardium, myocardium, epicardium, endothelium, and vascular smooth muscle cells were scored on intensity of VEGF-staining. The Mann-Witney test was used to test for significancy (p < 0.05) of the differences in staining. Increased vascularization as a result of VEGF was measured in both groups by standard randomization count. RESULTS: The endocardium, epicardium and endothelium of the coronary vessels showed significantly (p < 0.05) more intense VEGF-staining in the hydrops group than in the control group. The atria showed more intense staining than the ventricles in both groups. The hydropic fetuses showed a significantly increased number of coronary vessels in the myocardium. These vessels contained more blood cells than the coronary vessels in nonhydropic fetuses. CONCLUSION: The fetal heart appears to be a major source of excess VEGF in fetal hydrops.

p57KIP2 immunohistochemistry in early molar pregnancies: emphasis on its complementary role in the differential diagnosis of hydropic abortuses.

Morphologic examination still forms the main diagnostic tool in the differential diagnosis of molar pregnancies. However, the criteria are subjective and show considerable interobserver variability among pathologists. Once a diagnosis of molar pregnancy is made, DNA ploidy studies help to differentiate a triploid partial mole from diploid complete mole (CM). However, with earlier diagnosis and therapeutic evacuation of molar pregnancies, the differentiation of molar pregnancies from early nonmolar placentation is becoming increasingly difficult. The p57(KIP2) gene ( CDKN1C ) is strongly paternally imprinted and expressed from the maternal allele. Because CM lacks a maternal genome, p57(KIP2) immunostaining is correspondingly absent, whereas hydropic abortuses and partial mole show positive staining. We compared the use of p57(KIP2) staining in the differential diagnosis of 68 morphologically challenging cases of early first-trimester hydropic placentas. Diagnosis based on p57(KIP2) staining was compared with the original diagnosis based on morphology and DNA ploidy analysis. Concordant results were obtained in 65 of 68 cases studied. In 2 of 3 cases with a discordant diagnosis, microsatellite DNA genotyping analysis agreed with the results of p57(KIP2) staining, confirming that positive p57(KIP2) staining is a highly sensitive and specific marker for excluding CM in this setting. In addition, p57(KIP2) staining has the advantage of differentiating hydropic abortuses from CMs, a distinction not made by ploidy analysis. p57(KIP2) staining can be used in concert with ploidy studies to refine the diagnosis of early molar pregnancies.

Non-protein-bound iron and free radical damage in fetuses with rhesus haemolytic disease: influence of intrauterine transfusions.

OBJECTIVE: To determine iron-induced free radical damage in fetal rhesus haemolytic disease (RHD) before and after repeated intrauterine red blood cell transfusions and its relation to hydrops fetalis. DESIGN: Prospective, observational study. SETTING: Department of Obstetrics, Leiden University Medical Centre, the Netherlands. POPULATION: Fifty anaemic fetuses, including 13 hydropic ones, 9 preterm and 12 term neonates and 8 female non-pregnant adults. METHODS: Venous blood plasma samples were collected from 50 fetuses suffering from RHD preliminary to the first, and if appropriate, subsequent intrauterine red blood cell transfusions for determination of iron status including non-protein-bound iron (NPBI) and iron-binding primary antioxidant proteins, total plasma anti-oxidant capacity and its contributing secondary antioxidants (e.g. vitamin C, uric acid, sulphydryl groups and peroxidation products). Results were compared with values of healthy preterm and term neonates directly at birth and adult controls. Within the fetal haemolytic group, 13 hydropic fetuses were analysed as a separate group. MAIN OUTCOME MEASURES: Non-protein-bound iron, antioxidants, total antioxidant capacity and peroxidation products. Sub analysis of the outcome measures of the hydropic fetuses. RESULTS: RHD fetuses had at initial cordocentesis a significantly higher NPBI level and a significantly lower total plasma antioxidant capacity than control babies and adults. Their vitamin C tended to be more oxidised but lipid peroxidation had not increased, when compared with preterm babies. The repeated intrauterine red blood cell transfusions had a positive effect on the total antioxidant capacity of plasma and did not increase the concentration of NPBI. The hydropic fetuses, who had higher NPBI concentrations and lower plasma protein concentrations and total antioxidant capacity, did not show more peroxidation products in plasma than the non-hydropic fetuses. Fetuses without reversal of hydrops despite intrauterine transfusions showed decreasing levels of proteins with subsequent transfusions but peroxidation products remained constant. CONCLUSION: Repeated intrauterine red blood cell transfusions do not lead to free radical damage in the fetus in utero. Iron-induced free radical activity does not appear to play a causative role in the proceeding of hydrops fetalis in RHD.

p53 and Bcl-2 oncoprotein expression in placentas with hydropic changes and partial and complete moles.

Forty molar and non-molar placentas with hydropic changes (14 complete moles, 14 partial moles, and 12 hydropic non-molar placentas) were examined immunohistochemically for expression of oncoproteins p53 and Bcl-2. The data were evaluated to determine if p53 and Bcl-2 expression could aid in differentiating molar from non-molar pregnancies on the one hand and complete mole from partial mole on the other. Thirteen out of fourteen complete moles showed p53 expression (93%), 8 of the 14 partial moles expressed p53 (57%), and none of the non-molar pregnancies expressed p53 in the extravillous intermediate trophoblasts. Regarding Bcl-2, the syncytiotrophoblasts of most molar and non-molar placentas showed strong and diffuse positivity. These results suggest that p53 expression can be used as a distinguishing parameter between complete moles and placentas with hydropic changes on the one hand and to a lesser extent between partial moles and placentas with hydropic changes on the other hand. Bcl-2 cannot be used in the same way as p53.

Immunohistochemical distribution of vascular endothelial growth factor in the human placenta associated with hydrops fetalis.

The purpose of this study was to determine the distribution and the expression of vascular endothelial growth factor (VEGF) in human placentas obtained from 22 cases of nonimmunologic hydrops fetalis (NIHF), ranging from 25 to 41 weeks of gestation, as compared with those in 75 normal placentas. The terminal villi were examined immunohistochemically using rabbit anti-human VEGF immunoglobulin G. The expression of VEGF in the terminal villi was assessed by the ratio of the VEGF-positive area to the capillary area. Among the 22 placentas, 18 placentas were hydropic and appeared to be histologically immature, and the other 4 placentas, whose fetuses eventually recovered before their deliveries, were nonhydropic. In both the HF and normal placentas, syncytiotrophoblasts expressed VEGF in the villi throughout gestation. VEGF was also expressed by stromal cells in the terminal villi of normal placentas in only the first trimester, whereas its expression continued until the term of pregnancy in 12 of 18 HF placentas. The ratio of the VEGF-positive area to the capillary area was significantly higher in the terminal villi of all hydropic HF placentas than in those of the normal placentas but was entirely the same in the four nonhydropic placentas as in the normal control placentas. These results suggest that the persistent expression of VEGF by stromal cells in the hydropic villi of NIHF, in addition to the VEGF expression by syncytioptrophoblasts, seems to be a reaction to poor villous vascular development and to participate in the regulatory mechanisms of vascular function including angiogenesis and permeability.