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.

Prognostic accuracy of factors associated with poor outcome in prenatally diagnosed sacrococcygeal teratoma: A systematic review and meta-analysis.

Several factors associated with poor outcome in patients with prenatally diagnosed sacrococcygeal teratoma (SCT) have been found. However, the prognostic accuracy of these factors has not been well established. Therefore, we aimed to systematically review the prognostic accuracy of factors associated with poor outcome in these patients. We queried Search Premier, COCHRANE Library, EMCARE, EMBASE, PubMed, ScienceDirect, and Web of Science databases to identify studies regarding patients with prenatally diagnosed SCT. Poor outcome was defined as termination of pregnancy (TOP), intrauterine fetal death (IUFD), or perinatal death. We estimated the odds ratio of factors associated with poor outcome. Eleven studies (447 patients) were included. Overall mortality, including TOP, was 34.9%. Factors associated with poor outcome in fetuses with prenatally diagnosed SCT were cardiomegaly, hypervascular tumor, solid tumor morphology, fetal hydrops, and placentomegaly. A tumor volume to fetal weight ratio (TFR) of >0.12 before a gestational age of 24 weeks is predictive of poor outcome. The prognostic accuracy of factors associated with poor outcome in fetuses prenatally diagnosed with SCT seems promising. Factors associated with cardiac failure such as cardiomegaly, hypervascular tumor, solid tumor morphology, fetal hydrops, placentomegaly, and TFR >0.12 were found to be predictive of poor outcome.

Manifestations of thrombospondin type-1 domain-containing protein 1 gene mutation in an extremely premature infant with nonimmune hydrops fetalis.

Homozygous variants of the thrombospondin type-1 domain-containing 1 (THSD1) gene have recently been associated with nonimmune hydrops fetalis (NIHF; OMIM 236750) in infants, as well as with congenital heart disease, hemangiomas, prematurity, and embryonic lethality. Here, we report the first case of a biallelic variant of THSD1 in an extremely premature infant (25 weeks) who suffered from NIHF (eventually resolved) and other manifestations of the THSD1 variant, such as congenital heart disease and hemangiomas. Her prematurity was complicated by pulmonary hypertension and chronic lung disease. This case indicates that biallelic homozygous variants of THSD1 are among the likely causes of NIHF. Information from this case report will aid in determining the prognosis of NIHF caused by such variants in premature infants.

Case report of neonatal ductus venosus atresia.

INTRODUCTION: In the fetus, the ductus venosus (DV) connects the umbilical vein and the portal veins to the inferior vena cava in order to bypass the high-resistance hepatic vascular network. Via the Eustachian valve, the DV directs umbilical venous blood with the highest oxygen content preferentially towards the myocardium and the brain. An absence (agenesis) or a secondary obliteration of an initially normally developed DV (atresia) is associated with various shunt types and may lead to severe hydrops. CASE REPORT: A routine check-up of a healthy 34-year-old woman at 27 5/7 wks GA revealed a severe hydrops fetalis with pleural effusions and ascites. After birth at 28 0/7 wks GA, the bilateral pleural effusions needed drainage via thoracic drains. Arterial hypotension was initially treated with volume replacement and dopamine, later on adrenaline and hydrocortisone were added. The initial echocardiography showed normal anatomic structures and normal bi-ventricular function. Despite maximal intensive care treatment, a global respiratory and cardiovascular insufficiency developed. The girl died on fourth day of life. At autopsy, a secondary atresia of the DV was identified, and moreover a pathogenic de novo heterozygous mutation in the KRAS gene was found in the chorion biopsy probe. DISCUSSION: For all cases of non-haemolytic hydrops fetalis, a prenatal or postnatal sonography with Doppler examination of the venous system and of the heart should be performed. Furthermore, testing for RASopathies should be recommended especially in presence of increased nuchal translucency thickness and polyhydramnios.

Recurrent prenatal PIEZO1-related lymphatic dysplasia: Expanding molecular and ultrasound findings.

Generalized lymphatic dysplasia (GLD), characterized by lymphedema, lymphangiectasias, chylothorax, effusions, represents a recognized cause of fetal hydrops. We describe for the first time recurrent pregnancies showing different ultrasound presentations of lymphatic dysplasia. The first fetus displayed diffuse subcutaneous cysts and septations while the second one presented fetal hydrops. Exome sequencing results at 18 gestational weeks in the second pregnancy showed compound heterozygosity for two novel PIEZO1 variants, afterwards detected also in the first fetus and in the heterozygous parents. Both ultrasound and genetic findings expand the current knowledge of PIEZO1-related GLD. We suggest exome sequencing in hydropic fetuses with normal cytogenetics and in pregnancies with recurrent hydrops/lymphatic dysplasia.

A homozygous variant in growth and differentiation factor 2 (GDF2) may cause lymphatic dysplasia with hydrothorax and nonimmune hydrops fetalis.

The etiology of nonimmune hydrops fetalis is extensive and includes genetic disorders. We describe a term-born female neonate with late onset extensive nonimmune hydrops, that is, polyhydramnios, edema, and congenital bilateral chylothorax. This newborn was successfully treated with repetitive thoracocentesis, total parenteral feeding, octreotide intravenously and finally surgical pleurodesis and corticosteroids. A genetic cause seemed plausible as the maternal history revealed a fatal nonimmune hydrops fetalis. A homozygous truncating variant in GDF2 (c.451C>T, p.(Arg151*)) was detected with exome sequencing. Genetic analysis of tissue obtained from the deceased fetal sibling revealed the same homozygous variant. The parents and two healthy siblings were heterozygous for the GDF2 variant. Skin and lung biopsies in the index patient, as well as the revised lung biopsy of the deceased fetal sibling, showed lymphatic dysplasia and lymphangiectasia. To the best of our knowledge, this is the first report of an association between a homozygous variant in GDF2 with lymphatic dysplasia, hydrothorax and nonimmune hydrops fetalis.

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.

Biallelic loss of function variants in ATP1A2 cause hydrops fetalis, microcephaly, arthrogryposis and extensive cortical malformations.

The Na+/K+- ATPase acts as an ion pump maintaining the essential plasma membrane potential in all mammalian cell types, and is essential for many cellular functions. There are four α isoforms (α1, α2, α3 and α4) with distinct expression patterns, kinetic properties and substrate affinity. The α2-isoform is encoded by ATP1A2 and evidence supports its utmost importance in Cl- homeostasis in neurons, and in the function of respiratory neurons at birth. Monallelic pathogenic variants in ATP1A2 are associated with familial hemiplegic migraine type 2 (FHM2) and on rare occasions with alternating hemiplegia of childhood 1 (AHC1). To date, no instances of biallelic loss of function variants have been reported in humans. However, Atp1a2 homozygous loss of function knockout mice (α2-/- mice) show severe motor deficits, with lack of spontaneous movements, and are perinatally lethal due to absent respiratory activity. In this report we describe three newborns from two unrelated families, who died neonatally, presenting in utero with an unusual form of fetal hydrops, seizures and polyhydramnios. At birth they had multiple joint contractures (e.g. arthrogryposis), microcephaly, malformations of cortical development, dysmorphic features and severe respiratory insufficiency. Biallelic loss of function variants in ATP1A2, predicted to be pathogenic were found on whole exome sequencing. We propose that this is a distinctive new syndrome caused by complete absence of Na+/K+- ATPase α2-isoform expression.

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.

Fetal giant right cervical cyst causing severe tracheal compression: A case report.

RATIONALE: Fetal giant cervical cyst (FGCC) is a rare congenital anomaly. Sometimes FGCC may extend into the mediastinum, and result in severe tracheal compression, which is a life-threatening event at birth. PATIENT CONCERNS: We present a rare case of FGCC, which extended from the right neck into the superior mediastinum, and resulted in severe tracheal compression. DIAGNOSES: An FGCC was observed by ultrasonography and magnetic resonance imaging (MRI) at 27+4 weeks' gestation (WG). Fetal MRI at 35+1 WG showed that the FGCC was 3.3 × 8.2 × 7.5 cm and extended from the right neck into the superior mediastinum. Severe tracheal compression was observed and the inside diameter of the narrowest section of tracheostenosis appeared thread-like and measured only 0.1 cm. INTERVENTIONS: Cervical cyst reduction was performed prenatally under ultrasound guidance to alleviate the tracheal compression and maximize the chance of fetal survival 2 days before birth. At 36+3 WG, cesarean section was performed, and a female neonate was immediately delivered and intubated (3.5-mm tube) by an experienced anesthesiologist. Neonatal intralesional sclerotherapy and cystic component aspiration as guided by digital subtraction angiography were performed under general anesthesia. Anesthesia was maintained only with sevoflurane 3% in 2 L/min oxygen. Extubation was performed soon after surgery. OUTCOME: The neonate recovered uneventfully and was discharged 2 days postoperatively. After 140 days of follow-up, the neonate had recovered completely. LESSONS: If an FGCC is suspected by abdominal ultrasound, a fetal MRI is recommended to assess the severity of tracheal compression before birth, if feasible. An anesthesiologist should assess the risk of intubation failure at birth according to those results. If fetal severe tracheal compression is detected and it may result in inability of intubation at birth, prenatal cervical cyst reduction under ultrasound guidance may be effective for alleviating tracheal compression at birth, if feasible. This could maximize the chance of fetal survival. Improvement of fetal short- and long-term outcomes is important.

Early fetal hydropic changes are associated with moderate dilatation of the brain ventricular system: A clue to a possible link between cervical lymphatic engorgement and ventricular dilatation?

The aim of this study is to assess whether early cervical lymphatic obstruction is associated with a sonographically detectable dilatation of the ventricular system in the 1st trimester of pregnancy. In particular, the objective is to assess whether fetuses with non-immune hydrops fetalis (NIHF), cystic hygroma, or enlarged nuchal translucency (NT) have a greater atrial width/biparietal diameter (AW/BPD) ratio than normal at time of the combined first trimester screening scan. This retrospective study included 96 first trimester fetuses (33 normal and 63 with various degree of cervical lymphatic engorgement). Inclusion criteria were CRL in the 45-84 mm range and availability of one or more three-dimensional volume datasets of the fetal head, acquired from the BPD plane. Each three-dimensional volume dataset was opened and multiplanar correlation employed to align the three orthogonal planes. The ratio between the atrial width and the BPD (AW/BPD ratio) was used to evaluate the possible presence of increased amount of cerebrospinal fluid. Abnormal cases were placed into 4 categories: 1) enlarged non-septated NT 2.5-3.9 mm, no hydrops; 2) grossly enlarged non-septated NT / edema >3.9 mm; 3) cystic hygroma and/ or NIHF; 4) major anomalies with NT <2.5 mm. Presence of dilatation of the laterocervical jugular lymphatic sacs, karyotype and presence of congenital anomalies were also recorded. The One-way ANOVA test was used to compare means. Intra- and inter-observer variability were also assessed. The AW/BPD ratio was found to be significantly higher in fetuses with grossly enlarged NT/nuchal edema and NIHF/septated cystic hygroma than in normal (p <0.05 and p <0.01, respectively). Also, the AW/BPD ratio was significantly higher in NIHF/septated cystic hygroma than in enlarged NT 2.5-3.9 mm (p <0.05). In case of enlarged NT (2.5-3.9 mm), the AW/BPD ratio is significantly higher in presence of JLS (p <0.01). At the end of the first trimester, presence of cervical lymphatic engorgement, in terms of grossly enlarged NT, nuchal edema, septated cystic hygroma, and NIHF, is statistically associated with a moderate dilatation of the ventricular system. Of note, among fetuses with moderately enlarged NT, those with evidence of dilatation of the JLS show a statistically significant increase in the AW/BPD ratio.

Fetal-onset Congenital Dyserythropoietic Anemia Type 1 due to a Novel Mutation With Severe Iron Overload and Severe Cholestatic Liver Disease.

We report a rare case of severe congenital dyserythropoietic anemia type 1 with fetal onset. Our patient presented with fetal hydrops from 19 weeks of gestation, requiring multiple intrauterine transfusions. At birth, she had severe hemolytic anemia with severe jaundice, and was subsequently transfusion dependent. She eventually developed severe iron overload and fulminant liver failure before her demise at 5 months of age. Genetic testing revealed a novel mutation in CDAN1.

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.

A novel mutation in sphingosine-1-phosphate lyase causing congenital brain malformation.

INTRODUCTION: Recently recessive mutations in sphingosine-1-phosphate lyase (SGPL1) have been published as a cause of syndromic congenital nephrotic syndrome with adrenal insufficiency. We have identified a case with fetal hydrops and brain malformations due to a mutation in SGPL1. CASE REPORT: We report a patient presenting with severe fetal hydrops, congenital nephrotic syndrome and adrenal calcifications. MRI imaging showed generalized cortical atrophy with simplified gyral pattern and hypoplastic temporal lobes as well as cerebellar hypoplasia and hyperintensity in the pons. The boy deceased at 6 weeks of age. Via whole exome sequencing, we identified a novel homozygous frameshift mutation c.1233delC (p.Phe411Leufs∗56) in SGPL1. CONCLUSION: In our patient, we describe a novel mutation in sphingosine-1-phosphate lyase (SGPL1) leading to severe brain malformation. Neurodevelopmental phenotypes have been reported earlier, but not described in detail. To this end, we present a review on all published SGPL1-mutations and genotype-phenotype correlations focusing on neurodevelopmental outcomes. We hypothesized on the severe neurological phenotypes, which might be due to disruption of neuronal autophagy. Mutations in SGPL1 shall be considered in the differential diagnosis of fetal hydrops as well as congenital brain malformations and neuropathies.

Thymic teratoma presenting as non-immune hydrops fetalis

Teratomas are one of the most frequent tumors in the pediatric population. They occur anywhere along the midline of the body, following the course of the embryonic germ cell ridge. In the mediastinal location, they exert space occupying effects, leading to a myriad of complications, including non-immune hydrops fetalis. We describe a fatal case of an immature thymic teratoma in a neonate presenting with hydrops fetalis. This case emphasizes the importance of early diagnosis and surgical intervention in such cases.

A case of vasculopathy of unknown etiology associated with fatal hydrops fetalis and review of the literature on intimomedial mucoid degeneration.

Non-immune hydrops fetalis (NIHF) has a high mortality rate [1]. Many etiologies of NIHF have been identified, including cardiovascular abnormalities, severe anemia, and genetic defects. In patients with cardiovascular etiology, structural malformations lead to fluid accumulation resulting in increased intravascular hydrostatic pressure. We report a fatal case of NIHF in a 31 week gestational age, Caucasian neonate with heart remodeling associated with a stenotic vasculopathy of the right pulmonary artery. The artery revealed partial occlusion with vascular wall abnormalities, including disarrayed smooth muscle fibers, hyperplasia within the tunica media, and myxoid change within the media and intima. Identical vasculopathy was also identified within a mesenteric artery, and this contributed to hemorrhage and early ischemic necrosis of the small intestine, discovered on postmortem examination.

KLF1 E325K-associated Congenital Dyserythropoietic Anemia Type IV: Insights Into the Variable Clinical Severity.

We identified a child with KLF1-E325K congenital dyserythropoietic anemia type IV who experienced a severe clinical course, fetal anemia, hydrops fetalis, and postnatal transfusion dependence only partially responsive to splenectomy. The child also had complete sex reversal, the cause which remains undetermined. To gain insights into our patient's severe hematologic phenotype, detailed analyses were performed. Erythrocytes from the patient and parents demonstrated functional abnormalities of the erythrocyte membrane, attributed to variants in the α-spectrin gene. Hypomorphic alleles in SEC23B and YARS2 were also identified. We hypothesize that coinheritance of variants in relevant erythrocyte genes contribute to the clinical course in our patient and other E325K-linked congenital dyserythropoietic anemia IV patients with severe clinical phenotypes.

Non-immune hydrops fetalis: A retrospective analysis of 151 autopsies performed at a single center.

Kayki G, Güçer S, Akçören Z, Orhan D, Talim B, Yurdakök M, Yigit S, Boduroglu OK, Utine GE, Örgül G, Beksac MS. Non-immune hydrops fetalis: A retrospective analysis of 151 autopsies performed at a single center. Turk J Pediatr 2018; 60: 471-477. We retrospectively evaluated autopsies performed on 151 non-immune hydrops fetalis (NIHF) cases to determine the etiology and pathological findings. Further, cases identified between 1980 and 2004 were compared with those identified between 2005 and 2015 to investigate the improvement of diagnostic performance of our institution. The mean gestational age during the fetal autopsy was 25 weeks. There were 30 live-born infants in the study group. The etiology of NIHF could be determined in 91 cases (60.3%), while it remained undefined in remaining 60 cases. The most commonly associated pathological conditions were cardiovascular malformations (11.3%), followed by chromosomal abnormalities (9.3%). Prior to 20th gestation week, genetic anomalies and cystic hygromas were the most common etiological factors, and after 30 weeks of gestation, cardiac abnormalities were found to be the most common causes. With time, the rate of undefined cases decreased from 48.4% to 33.75%. NIHF is a complex medical condition necessitating a multidisciplinary management approach. Progress in molecular genetics and imaging techniques is expected to improve diagnostic performance for rapid and better identification.

SIFD as a novel cause of severe fetal hydrops and neonatal anaemia with iron loading and marked extramedullary haemopoiesis.

SIFD describes a heritable, syndromic condition characterised principally by sideroblastic anaemia (SA) with immunodeficiency, fevers and developmental delay, arising in mutations within the TRNT1 gene. Other clinical manifestations of SIFD include cardiomyopathy, seizures, sensorineural hearing loss, renal dysfunction, metabolic abnormalities, hepatosplenomegaly and retinitis pigmentosa.Presentation of SIFD is variable but typically in early childhood with SA or with fever. In this report, we extend the described SIFD phenotype. We describe a kindred in which the index case presented with fetal hydrops, and early neonatal death, and the second child had severe anaemia at delivery. Both cases had prominent extramedullary erythropoiesis and numerous circulating nucleated red blood cells.