Arterial Stiffness as a Cardiovascular Risk Factor for the Development of Preeclampsia and Pharmacopreventive Options.

Arterial Stiffness (AS) describes the rigidity of the arterial walls. Epidemiological studies have shown that increased AS is an independent predictive marker of Cardiovascular (CV) morbidity and mortality in both pregnant and non-pregnant women. Preeclampsia (PE), a form of pregnancy-induced hypertension, affects approximately 5% of pregnancies worldwide. Preeclamptic women have a higher risk of CV Disease (CVD), mainly because PE damages the heart's ability to relax between contractions. Different pharmacological approaches for the prevention of PE have been tested in clinical trials (e.g., aspirin, enoxaparin, metformin, pravastatin, and sildenafil citrate). In current clinical practice, only low-dose aspirin is used for PE pharmacoprevention. However, low-dose aspirin does not prevent term PE, which is the most common form of PE. Compromised vascular integrity precedes the onset of PE and therefore, AS assessment may constitute a promising predictive marker of PE. Several non-invasive techniques have been developed to assess AS. Compared with normotensive pregnancies, both Carotid-Femoral Pulse Wave Velocity (cfPWV) and Augmentation Index (AIx) are increased in PE. In view of simplicity, reliability, and reproducibility, there is an interest in oscillometric AS measurements in pregnancies complicated by PE.

Unexplained infertility patients present the mostly impaired levels of progesterone receptors: Prospective observational study.

PROBLEM: Τo assess the endometrial expression of progesterone receptors in various subgroups of infertile women during implantation window. ΜETHODS: A prospective observational study was performed during March 2013-February 2017. Infertile women were categorized to those with tubal factor, ovarian failure, endometriosis or unexplained infertility. Endometrial biopsy was obtained on 7th-8th postovulatory day. Total progesterone receptors' PR(A + B) and type-B receptors' (PR-B) expression were compared between all categories of infertile and fruitful controls. RESULTS: There were overall 30 patients with tubal factor infertility (group 1), 30 with ovarian failure (group 2), 20 with endometriosis (group 3) and 20 with unexplained infertility (group 4). The control group consisted of 30 fertile patients. Patients with unexplained infertility presented the lowest levels of epithelial endometrial expression both regarding PR(A + B) and PR-B receptors. PgR(A + B) h-score in luminal epithelial cells was 106.4 ± 14.7 for cases with unexplained infertility vs 219.7 ± 15.8 for controls (P < .001). Similarly, PgR(A + B) h-score in glandular epithelial cells was 109.7 ± 13.9 vs 220.1 ± 17.2 (P < .001). Relative remarks were made for type-B progesterone receptors. CONCLUSION: Εndometrial expression of progesterone receptors is impaired in women with unexplained infertility. Therapeutic strategies targeting on improving progesterone receptors' expression may significantly affect final reproductive outcome.

Olig2 and Hes regulatory dynamics during motor neuron differentiation revealed by single cell transcriptomics.

During tissue development, multipotent progenitors differentiate into specific cell types in characteristic spatial and temporal patterns. We addressed the mechanism linking progenitor identity and differentiation rate in the neural tube, where motor neuron (MN) progenitors differentiate more rapidly than other progenitors. Using single cell transcriptomics, we defined the transcriptional changes associated with the transition of neural progenitors into MNs. Reconstruction of gene expression dynamics from these data indicate a pivotal role for the MN determinant Olig2 just prior to MN differentiation. Olig2 represses expression of the Notch signaling pathway effectors Hes1 and Hes5. Olig2 repression of Hes5 appears to be direct, via a conserved regulatory element within the Hes5 locus that restricts expression from MN progenitors. These findings reveal a tight coupling between the regulatory networks that control patterning and neuronal differentiation and demonstrate how Olig2 acts as the developmental pacemaker coordinating the spatial and temporal pattern of MN generation.

Antenatal depression among women hospitalized due to threatened preterm labor in a high-risk pregnancy unit in Greece.

PURPOSE: Estimates for the prevalence of antenatal depression vary widely across different studies and especially concerning high-risk pregnancies. Threatened preterm labor is the most common indication for antenatal obstetric hospitalization. The aim of this study was to screen for depressive symptoms among pregnant women hospitalized in a high-risk pregnancy unit due to threatened preterm labor and also to investigate possible associated risk factors. MATERIALS AND METHODS: A total of 103 pregnant women admitted at >24 and <36 gestational weeks were eligible to participate in the study. The Greek version of the Edinburgh Postnatal Depression Scale (EPDS) was used to detect depressive symptoms on admission. A cutoff score of >13 was considered as indicative of depression. Possible associated risk factors were also investigated. RESULTS: The prevalence of antenatal depression (score >13) was 24.3% (n = 25). In the multivariate analysis, antenatal depression was significantly correlated with thoughts of abortion (OR: 6.208; 95% CI: 1.141-33.765). CONCLUSIONS: About one quarter of the pregnant women hospitalized in the HRPU due to threatened preterm labor were depressed based on the EPDS. Thoughts of abortion were associated with a sixfold increase in the risk of depression, while no associations were found between antenatal depression and other sociodemographic and obstetric parameters.

Four alpha ganglion cell types in mouse retina: Function, structure, and molecular signatures.

The retina communicates with the brain using ≥30 parallel channels, each carried by axons of distinct types of retinal ganglion cells. In every mammalian retina one finds so-called "alpha" ganglion cells (αRGCs), identified by their large cell bodies, stout axons, wide and mono-stratified dendritic fields, and high levels of neurofilament protein. In the mouse, three αRGC types have been described based on responses to light steps: On-sustained, Off-sustained, and Off-transient. Here we employed a transgenic mouse line that labels αRGCs in the live retina, allowing systematic targeted recordings. We characterize the three known types and identify a fourth, with On-transient responses. All four αRGC types share basic aspects of visual signaling, including a large receptive field center, a weak antagonistic surround, and absence of any direction selectivity. They also share a distinctive waveform of the action potential, faster than that of other RGC types. Morphologically, they differ in the level of dendritic stratification within the IPL, which accounts for their response properties. Molecularly, each type has a distinct signature. A comparison across mammals suggests a common theme, in which four large-bodied ganglion cell types split the visual signal into four channels arranged symmetrically with respect to polarity and kinetics.

LIF endometrial expression is impaired in women with unexplained infertility while LIF-R expression in all infertility sub-groups.

The main objective of our study was to study LIF and LIF-R endometrial expression during the implantation window in the various sub-groups of infertile women according to infertility cause. A prospective observational case-control study was performed from March 2013 to February 2016. Infertile women consisted of the patients' group (group 2) while fertile women were the control group (group 1). Infertile women were divided according to infertility cause in women with tubal factor (group 2a), poor ovarian reserve (group 2b), endometriosis (group 2c) and unexplained infertility (group 2d). Endometrial biopsy was performed on 7th-8th postovulatory menstrual day. Leukemia Inhibitory Factor (LIF) and LIF-Receptor (LIF-R) expression in epithelial and stromal cells were assessed with Immunohistochemistry (IHC). There were 20 infertile with poor ovarian reserve, 15 with tubal factor, 10 with endometriosis and 15 with unexplained infertility included in the analysis. LIF expression in patients with unexplained infertility was significantly compared with controls (P=0.006). No significant difference was observed between patients with tubal factor, poor ovarian reserve and endometriosis compared with control group (P=0.78, P=0.44 and P=0.56 respectively). Analysis of LIF-R expression in sub-categories of infertility indicated that expression was significantly decreased in all sub-groups of infertility. Our study indicated impaired LIF expression levels only in women with unexplained infertility, while LIF-R expression was impaired in all sub-groups of infertile women. Further multicenter prospective studies should be performed in order to assess the exact etiopathogenetic role of these cytokines in the molecular background of infertility.

Cumulative High-Grade Squamous Intraepithelial Lesion Rate and Need for Surgical Intervention of Atypical Squamous Cells of Undetermined Significance Cytology-Diagnosed Patients: A Prospective Study.

OBJECTIVE: Τhe study aimed to study the rate of atypical squamous cells of undetermined significance (ASCUS) that progressed to high-grade squamous intraepithelial lesions (HGSIL), as well as the number of patients who finally necessitated a surgical intervention during follow-up. METHODS: A prospective study was conducted on patients admitted for colposcopy during 2007-2012. We exclusively included those who presented with newly ASCUS diagnosis, while patients with a history of cervical intraepithelial neoplasia (CIN) were excluded. Primary end points were the cumulative rate of HGSIL during follow-up and the rate of surgical procedures performed because of such lesions. RESULTS: There were 134 ASCUS cases included. Overall, there were 48 (35.8%) surgical excision procedures performed to treat or eliminate HGSIL during the follow-up period. According to the final histopathology of surgical specimens, the cumulative rate of CIN2 or higher cervical lesions was 28.4% (n = 38). CONCLUSION: The cumulative rate of CIN2+ during follow-up period was almost 30% for patients with ASCUS, with the necessity for interventional treatment being even higher.

High efficiency near diffraction-limited mid-infrared flat lenses based on metasurface reflectarrays.

We report the first demonstration of a mid-IR reflection-based flat lens with high efficiency and near diffraction-limited focusing. Focusing efficiency as high as 80%, in good agreement with simulations (83%), has been achieved at 45° incidence angle at λ = 4.6 µm. The off-axis geometry considerably simplifies the optical arrangement compared to the common geometry of normal incidence in reflection mode which requires beam splitters. Simulations show that the effects of incidence angle are small compared to parabolic mirrors with the same NA. The use of single-step photolithography allows large scale fabrication. Such a device is important in the development of compact telescopes, microscopes, and spectroscopic designs.

Fertility-sparing management and obstetric outcomes in a 20-year-old patient with a Sertoli-Leydig cell tumor of the ovary: A case report and review of the literature.

Sertoli-Leydig cell tumors (SLCTs) are an uncommon subtype of sex-cord stromal tumors of the ovary, which most commonly arise in women of reproductive age, creating an issue with regard to the preservation of fertility. The clinical manifestation of SLCTs varies widely, ranging from an asymptomatic clinical profile to extreme virilization. Correct diagnosis of SLCT is crucial and is primarily based on histopathological results. The current study presents the case of a 20-year-old woman who underwent unilateral salpingo-oophorectomy and adjuvant chemotherapy due to the diagnosis of an SLCT of the left ovary. Almost 2 years after the initial surgery, during the follow-up period, the patient conceived normally. Pregnancy was uneventful and the patient vaginally delivered a healthy infant at 38 weeks of gestation. A total of 1 year after delivery (3 years after the initial diagnosis), follow-up of the patient did not reveal any disease recurrence. In conclusion, SLCTs may be adequately treated by fertility-sparing surgery and chemotherapy in young women who wish to preserve their fertility. Natural conception, an uncomplicated pregnancy and a vaginal delivery are possible.

Pravastatin improves pregnancy outcomes in obstetric antiphospholipid syndrome refractory to antithrombotic therapy.

BACKGROUND: Administration of conventional antithrombotic treatment (low-dose aspirin plus low-molecular weight heparin [LDA+LMWH]) for obstetric antiphospholipid syndrome (APS) does not prevent life-threatening placenta insufficiency-associated complications such as preeclampsia (PE) and intrauterine growth restriction (IUGR) in 20% of patients. Statins have been linked to improved pregnancy outcomes in mouse models of PE and APS, possibly due to their protective effects on endothelium. Here, we investigated the use of pravastatin in LDA+LMWH-refractory APS in patients at an increased risk of adverse pregnancy outcomes. METHODS: We studied 21 pregnant women with APS who developed PE and/or IUGR during treatment with LDA+LMWH. A control group of 10 patients received only LDA+LMWH. Eleven patients received pravastatin (20 mg/d) in addition to LDA+LMWH at the onset of PE and/or IUGR. Uteroplacental blood hemodynamics, progression of PE features (hypertension and proteinuria), and fetal/neonatal outcomes were evaluated. RESULTS: In the control group, all deliveries occurred preterm and only 6 of 11 neonates survived. Of the 6 surviving neonates, 3 showed abnormal development. Patients who received both pravastatin and LDA+LMWH exhibited increased placental blood flow and improvements in PE features. These beneficial effects were observed as early as 10 days after pravastatin treatment onset. Pravastatin treatment combined with LDA+LMWH was also associated with live births that occurred close to full term in all patients. CONCLUSION: The present study suggests that pravastatin may improve pregnancy outcomes in women with refractory obstetric APS when taken at the onset of PE or IUGR until the end of pregnancy.

Prevalence of antenatal depression and associated factors among pregnant women hospitalized in a high-risk pregnancy unit in Greece.

PURPOSE: Women who face pregnancy complications may require hospitalization in a high-risk pregnancy unit (HRPU), and this may have a negative impact on the pregnant woman's mental health. The purpose of this study was to screen for depressive symptoms in pregnant women admitted in a high-risk pregnancy unit and also to investigate associated risk factors. METHODS: This was a cross-sectional study that enrolled pregnant women admitted at ≥24 gestational weeks in a university hospital HRPU, between September 2014 and November 2015. The Edinburgh Postnatal Depression Scale was used to assess depressive symptoms on admission. A cutoff score ≥13 was considered as indicative of depression. Test results were then correlated with the reasons that led to the women's admission as well as socio-demographic characteristics. RESULTS: Overall, 157 of the women admitted in the HRPU during the study period were eligible for the study and agreed to complete the questionnaire. The mean age of the pregnant women was 30 ± 6 years, and the mean gestational week at admission was 32 ± 3 weeks. The prevalence of antenatal depression (score ≥13) was 28 % (44/157). In the multivariate analysis, antenatal depression was significantly correlated with smoking (OR = 2.681, 95 % CI 1.089-6.601) and the existence of thoughts for pregnancy termination (OR = 3.624, 95 % CI 1.149-11.427). CONCLUSIONS: Approximately one quarter of pregnant women hospitalized in the HRPU may show signs of depression at the time of admission. Smoking and an unwanted pregnancy were found to be independently associated with antenatal depression, whereas no association was found with any obstetric parameters.

Two Pairs of ON and OFF Retinal Ganglion Cells Are Defined by Intersectional Patterns of Transcription Factor Expression.

Visual information is conveyed to the brain by axons of >30 retinal ganglion cell (RGC) types. Characterization of these types is a prerequisite to understanding visual perception. Here, we identify a family of RGCs that we call F-RGCs on the basis of expression of the transcription factor Foxp2. Intersectional expression of Foxp1 and Brn3 transcription factors divides F-RGCs into four types, comprising two pairs, each composed of closely related cells. One pair, F-mini(ON) and F-mini(OFF), shows robust direction selectivity. They are among the smallest RGCs in the mouse retina. The other pair, F-midi(ON) and F-midi(OFF), is larger and not direction selective. Together, F-RGCs comprise >20% of RGCs in the mouse retina, halving the number that remain to be classified and doubling the number of known direction-selective cells. Co-expression of Foxp and Brn3 genes also marks subsets of RGCs in macaques that could be primate homologs of F-RGCs.

LIF and LIF­R expression in the endometrium of fertile and infertile women: A prospective observational case­control study.

The aim of the present study was to determine the expression of leukemia inhibitory factor (LIF) and LIF receptor (LIF­R) in the endometrium of fertile and infertile women during the implantation window. A prospective study was conducted between March 2013 and March 2015 at Iakentro, Infertility Treatment Center (Thessaloniki, Greece) and the 3rd Department of Obstetrics and Gynecology, Aristotle University of Thessaloniki (Thessaloniki, Greece). The patient group consisted of women diagnosed with infertility, whereas the control group consisted of women who had delivered at least one live newborn (fertile women). An endometrial biopsy was obtained using a Pipelle on day 7 or 8 post­ovulation, and the expression of LIF and LIF­R was assessed by immunohistochemistry in epithelial and stromal cells. Primary outcomes included positive cellular percentage, staining intensity and H­score. P<0.05 was considered to indicate a statistically significant difference. Overall, 45 women were included in the present analysis (15 fertile women and 30 infertile women). Mean age was 32.8±6.0 years for the fertile group, and 37.6±3.7 for the infertile group. LIF and LIF­R expression was significantly reduced in the epithelial cells of infertile women (P=0.05 and P=0.006, respectively). However, no significant differences were detected with regards to the expression of LIF in stromal cells (P=0.95). In addition, LIF­R expression was relatively higher in the stromal cells of the fertile group; however, the difference did not reach statistical significance (P=0.10). In conclusion, endometrial expression of LIF and LIF­R is significantly reduced in the epithelial cells of infertile women. Expression patterns of LIF­R in stromal cells require further research in order to achieve definitive results.

Expression of progesterone receptors is significantly impaired in the endometrium of infertile women during the implantation window: a prospective observational study.

OBJECTIVE: To compare the expression of progesterone receptors (A + B) and type-B progesterone receptors in the epithelial and stromal cells of fertile and infertile women. METHODS: Women were divided into two groups, the group of fertile controls (group 1) and the group of infertile women (group 2) and were set on regular ultrasound imaging in order to detect ovulation. An endometrial biopsy was obtained on the seventh or eighth post-ovulatory day. Immunohistochemistry was performed to measure percentage of positive nuclei, intensity of staining and h-score for progesterone receptors (PgR) (A + B) as well as type-B progesterone receptors in epithelial and stromal cells. Secondary outcomes included endometrial tissue dating, the rate of tissues being out-of-phase and endometrial thickness. RESULTS: Endometrial issue was obtained from 15 fertile and 30 infertile women. Expression of PgR (A + B) and PgR type-B was significantly lower in the epithelial cells of infertile women. PgR (A + B) h-score was 220.0 ± 18.5 for fertile versus 147.3 ± 18.0 for infertile women (p = 0.02). PgR type-B h-score in epithelial cells was 166.8 ± 30.7 for fertile versus 90.8 ± 20.6 for infertile (p = 0.04). No significant difference was observed in stromal cells. CONCLUSIONS: Expression levels of PgR (A + B) as well as type-B receptors are significantly lower in the epithelial cells of infertile women during implantation window.

A clinicopathological study of atypical leiomyomas: Benign variant leiomyoma or smooth-muscle tumor of uncertain malignant potential.

Atypical leiomyomas are histopathologically recognized by moderate to severe pleomorphic atypical tumor cells showing low mitotic counts without coagulative tumor cell necrosis. The histopathological features and clinical behavior of these tumors are unclear. The surgical management of these lesions includes myomectomy and hysterectomy. The current study presents 5 cases of women with atypical leiomyomas that were managed surgically. The clinicopathological characteristics of the patients and recurrences were analyzed. The median age of the patients was 43 years old. While 3 out of 5 patients were treated by hysterectomy (with or without salpingo-oophorectomy), the remaining 2 patients were treated by myomectomy. The median mitotic index was 3 mitotic figures/10 high-power fields. The post-operative course of all patients was uneventful, and there was no evidence of local or distant recurrence in a median follow-up time of 72 months. The treatment of choice for atypical leiomyomas is hysterectomy. However, myomectomy may be an option for fertility sparing cases. A thorough consultation with regard to the uncertain behavior of such tumors and a rigorous follow-up must be offered in such patients.

Pregnancy after liver transplantation. How safe? A retrospective case-series study in a large tertiary hospital.

OBJECTIVE: To study pregnancies achieved after liver transplantation in terms of obstetric complications, maternal, neonatal outcomes and post-pregnancy allograft function. METHODS: A retrospective study of prospectively collected data was conducted, enrolling women with a history of liver transplantation performed in the Transplantation Unit of our hospital that delivered in our department. Obstetric characteristics and antenatal complications were reviewed. Apgar score, admission to Neonatal Intensive Care Unit (NICU) and need for emergency intubation were analyzed. Outcomes of regular follow-up concerning all complications of allograft function observed after pregnancy were also studied. RESULTS: There were five cases of allograft recipients delivering their pregnancies during the study period. Mean maternal age was 32.2 ± 5 years. Interval from transplantation to delivery ranged from 40 to 219 months. Mean gestational week at delivery was 34.4 ± 2.5 weeks. Antenatal complications observed were pre-eclampsia (3 of 5 cases) and vaginal bleeding (1 of 5 cases). All preterm neonates were admitted to NICU, but no emergency intubation was demanded. One patient died a month after delivery, while three others were complicated by implant dysfunction up to 5 years after the delivery. CONCLUSION: Pregnancy in a liver transplant recipient is associated with complications for mother and infant.

Achromatic Metasurface Lens at Telecommunication Wavelengths.

Nanoscale optical resonators enable a new class of flat optical components called metasurfaces. This approach has been used to demonstrate functionalities such as focusing free of monochromatic aberrations (i.e., spherical and coma), anomalous reflection, and large circular dichroism. Recently, dielectric metasurfaces that compensate the phase dispersion responsible for chromatic aberrations have been demonstrated. Here, we utilize an aperiodic array of coupled dielectric nanoresonators to demonstrate a multiwavelength achromatic lens. The focal length remains unchanged for three wavelengths in the near-infrared region (1300, 1550, and 1800 nm). Experimental results are in agreement with full-wave simulations. Our findings are an essential step toward a realization of broadband flat optical elements.

Cytomegalovirus, Toxoplasma gondii and Rubella Vertical Transmission Rates According to Mid-trimester Amniocentesis: A Retrospective Study.

OBJECTIVE: To examine vertical transmission rates of Cytomegalovirus, Toxoplasma Gondii and Rubella infections according to amniotic fluid PCR analysis. METHODS: A retrospective analysis of mid-trimester amniocenteses performed in in pregnancies with diagnosed maternal infection by Cytomegavirus (CMV), Rubella or Toxoplasma gondii during 1994-2008 was performed. Vertical transmission rates were observed according to the presence of the infectious agent's DNA in the amniotic fluid. A univariate regression model was also performed to investigate possible correlations between transmission and epidemiological parameters. RESULTS: Overall, 7033 amniocenteses were performed during study's period, of which 166 (2.4%) with the indication of maternal infection by CMV, Rubella or Toxoplasma. Mean maternal age was 27.4 ± 2.5 years and the mean gestational age at amniocentesis was 18.7 ± 2.5 weeks. Vertical transmission was observed in 21 cases (12.7%). Transmission rate was 17.3% in cases with infection from CMV, 9.5% from Toxoplasma gondii and 7.8% from Rubella (P = .05). Maternal age was the only parameter being significantly associated with increased risk for vertical transmission (P = .04). CONCLUSIONS: According to our results, overall vertical transmission rate marginally exceeds 10%. CMV infection is characterized by relatively higher transplacental transmission rate, while increased maternal age appears to be associated with a higher risk for vertical transmission.

Birth weight independently affects morbidity and mortality of extremely preterm neonates.

BACKGROUND: Neonates born between 24 + 0 and 27 + 6 gestational weeks, widely known as extremely preterm neonates, present a category characterized by increased neonatal mortality and morbidity. Main objective of the present study is to analyze the effect of various epidemiological and pregnancy-related parameters on unfavorable neonatal mortality and morbidity outcomes. METHODS: A retrospective study was performed enrolling cases delivered during 2003 - 2008 in our department. Cases of neonatal death as well as pathological Apgar score (≤ 4 in the first and ≤ 7 in the fifth minute of life), need for emergency resuscitation, respiratory disease syndrome (RDS), neonatal asphyxia, intraventricular hemorrhage (IVH) and neonatal death were recorded for neonates of our analysis. A multivariate regression model was used to correlate these outcomes with gestational week at delivery, maternal age, parity, kind of gestation (singleton or multiple), intrauterine growth restriction (IUGR), birth weight (BW), preterm premature rupture of membranes (PPROM), mode of delivery (vaginal delivery or cesarean section) and antenatal use of corticosteroids. RESULTS: Out of 5,070 pregnancies delivered, 57 extremely preterm neonates were born (1.1%). Mean BW was 780.35 ± 176.0, RDS was observed in 93.0% (n = 53), resuscitation was needed in 54.4% (n = 31) while overall mortality rate was 52.6% (n = 30). BW was independently associated with neonatal death (P = 0.004), pathological Apgar score in the first (P = 0.05) and fifth minute of life (P = 0.04) as well as neonatal sepsis (P = 0.05). CONCLUSION: BW at delivery is independently affecting neonatal mortality and morbidity parameters in extremely preterm neonates.

Foxp1-mediated programming of limb-innervating motor neurons from mouse and human embryonic stem cells.

Spinal motor neurons (MNs) control diverse motor tasks including respiration, posture and locomotion that are disrupted by neurodegenerative diseases such as amyotrophic lateral sclerosis and spinal muscular atrophy. Methods directing MN differentiation from stem cells have been developed to enable disease modelling in vitro. However, most protocols produce only a limited subset of endogenous MN subtypes. Here we demonstrate that limb-innervating lateral motor column (LMC) MNs can be efficiently generated from mouse and human embryonic stem cells through manipulation of the transcription factor Foxp1. Foxp1-programmed MNs exhibit features of medial and lateral LMC MNs including expression of specific motor pool markers and axon guidance receptors. Importantly, they preferentially project axons towards limb muscle explants in vitro and distal limb muscles in vivo upon transplantation-hallmarks of bona fide LMC MNs. These results present an effective approach for generating specific MN populations from stem cells for studying MN development and disease.