In utero delivery of miRNA induces epigenetic alterations and corrects pulmonary pathology in congenital diaphragmatic hernia

Structural fetal diseases, such as congenital diaphragmatic hernia (CDH) can be diagnosed prenatally. Neonates with CDH are healthy in utero as gas exchange is managed by the placenta, but impaired lung function results in critical illness from the time a baby takes its first breath. MicroRNA (miR) 200b and its downstream targets in the TGF-β pathway are critically involved in lung branching morphogenesis. Here, we characterize the expression of miR200b and the TGF-β pathway at different gestational times using a rat model of CDH. Fetal rats with CDH are deficient in miR200b at gestational day 18. We demonstrate that novel polymeric nanoparticles loaded with miR200b, delivered in utero via vitelline vein injection to fetal rats with CDH results in changes in the TGF-β pathway as measured by qRT-PCR; these epigenetic changes improve lung size and lung morphology, and lead to favorable pulmonary vascular remodeling on histology. This is the first demonstration of in utero epigenetic therapy to improve lung growth and development in a pre-clinical model. With refinement, this technique could be applied to fetal cases of CDH or other forms of impaired lung development in a minimally invasive fashion.

Prenatal Somatic Cell Gene Therapies: Charting a Path Toward Clinical Applications (Proceedings of the CERSI-FDA Meeting)

We are living in a golden age of medicine in which the availability of prenatal diagnosis, fetal therapy, and gene therapy/editing make it theoretically possible to repair almost any defect in the genetic code. Furthermore, the ability to diagnose genetic disorders before birth and the presence of established surgical techniques enable these therapies to be delivered safely to the fetus. Prenatal therapies are generally used in the second or early third trimester for severe, life-threatening disorders for which there is a clear rationale for intervening before birth. While there has been promising work for prenatal gene therapy in preclinical models, the path to a clinical prenatal gene therapy approach is complex. We recently held a conference with the University of California, San Francisco-Stanford Center of Excellence in Regulatory Science and Innovation, researchers, patient advocates, regulatory (members of the Food and Drug Administration), and other stakeholders to review the scientific background and rationale for prenatal somatic cell gene therapy for severe monogenic diseases and initiate a dialogue toward a safe regulatory path for phase 1 clinical trials. This review represents a summary of the considerations and discussions from these conversations.

Surface conjugation of antibodies improves nanoparticle uptake in bronchial epithelial cells

BACKGROUND

Advances in Molecular Therapy have made gene editing through systemic or topical administration of reagents a feasible strategy to treat genetic diseases in a rational manner. Encapsulation of therapeutic agents in nanoparticles can improve intracellular delivery of therapeutic agents, provided that the nanoparticles are efficiently taken up within the target cells. In prior work we had established proof-of-principle that nanoparticles carrying gene editing reagents can mediate site-specific gene editing in fetal and adult animals in vivo that results in functional disease improvement in rodent models of β-thalassemia and cystic fibrosis. Modification of the surface of nanoparticles to include targeting molecules (e.g. antibodies) holds the promise of improving cellular uptake and specific cellular binding.

METHODS AND FINDINGS

To improve particle uptake for diseases of the airway, like cystic fibrosis, our group tested the impact of nanoparticle surface modification with cell surface marker antibodies on uptake in human bronchial epithelial cells in vitro. Binding kinetics of antibodies (Podoplanin, Muc 1, Surfactant Protein C, and Intracellular Adhesion Molecule-1 (ICAM)) were determined to select appropriate antibodies for cellular targeting. The best target-specific antibody among those screened was ICAM antibody. Surface conjugation of nanoparticles with antibodies against ICAM improved cellular uptake in bronchial epithelial cells up to 24-fold.

CONCLUSIONS

This is a first demonstration of improved nanoparticle uptake in epithelial cells using conjugation of target specific antibodies. Improved binding, uptake or specificity of particles delivered systemically or to the luminal surface of the airway would potentially improve efficacy, reduce the necessary dose and thus safety of administered therapeutic agents. Incremental improvement in the efficacy and safety of particle-based therapeutic strategies may allow genetic diseases such as cystic fibrosis to be cured on a fundamental genetic level before birth or shortly after birth.

A narrative review of in utero gene therapy: advances, challenges, and future considerations

The field of in utero gene therapy (IUGT) represents a crossroad of technologic advancements and medical ethical boundaries. Several strategies have been developed for IUGT focusing on either modifying endogenous genes, replacing missing genes, or modifying gene transcription products. The list of candidate diseases such as hemoglobinopathies, cystic fibrosis, lysosomal storage disorders continues to grow with new strategies being developed as our understanding of their respective underlying molecular pathogenesis increases. Treatment in utero has several distinct advantages to postnatal treatment. Biologic and physiologic phenomena enable the delivery of a higher effective dose, generation of immune tolerance, and the prevention of phenotypic onset for genetic diseases. Therapeutic technology for IUGT including CRISPR-Cas9 systems, zinc finger nucleases (ZFN), and peptide nucleic acids (PNAs) has already shown promise in animal models and early postnatal clinical trials. While the ability to detect fetal diagnoses has dramatically improved with developments in ultrasound and next-generation sequencing, treatment options remain experimental, with several translational gaps remaining prior to implementation in the clinical realm. Complicating this issue, the potential diseases targeted by this approach are often debilitating and would otherwise prove fatal if not treated in some manner. The leap from small animals to large animals, and subsequently, to humans will require further vigorous testing of safety and efficacy.

Nanoparticles for delivery of agents to fetal lungs

Fetal treatment of congenital lung disease, such as cystic fibrosis, surfactant protein syndromes, and congenital diaphragmatic hernia, has been made possible by improvements in prenatal diagnostic and interventional technology. Delivery of therapeutic agents to fetal lungs in nanoparticles improves cellular uptake. The efficacy and safety of nanoparticle-based fetal lung therapy depends on targeting of necessary cell populations. This study aimed to determine the relative distribution of nanoparticles of a variety of compositions and sizes in the lungs of fetal mice delivered through intravenous and intra-amniotic routes. Intravenous delivery of particles was more effective than intra-amniotic delivery for epithelial, endothelial and hematopoietic cells in the fetal lung. The most effective targeting of lung tissue was with 250nm Poly-Amine-co-Ester (PACE) particles accumulating in 50% and 44% of epithelial and endothelial cells. This study demonstrated that route of delivery and particle composition impacts relative cellular uptake in fetal lung, which will inform future studies in particle-based fetal therapy.

An Evidence-Based Guideline Supporting Restricted Opioid Prescription after Pediatric Appendectomy

BACKGROUND/PURPOSE

Surgeon overprescription of opioids is a modifiable contributor to the opioid epidemic. No clear guidelines exist for prescribing opioids to younger patients after surgery. We sought to determine postoperative opioid needs in pediatric/young adult patients after laparoscopic appendectomy.

METHODS

Patients 5-20 years old who underwent laparoscopic appendectomy were included for study. All consented patients underwent chart review and were additionally called for an attempted interview. Caregivers were queried on analgesic use and adequacy of pain relief. The main outcome measures were: quantity of opioid used, desire for an opioid, presence of pain ≥4/10, and need for follow-up/call owing to pain. All opioids were converted into morphine milligram equivalents (MME).

RESULTS

Seventy-three patients qualified for the study, 49 of whom completed a postoperative telephone interview. Of the interviewees, 83% did not use or desire an opioid and reported pain <4/10 after discharge. Five patients used an opioid upon discharge, and the average MME consumed was 23 (equivalent to 3 pills of 5 mg oxycodone). No zero-opioid patients had unanticipated follow-up for pain concerns.

CONCLUSIONS

After hospital discharge following laparoscopic appendectomy, most patients have adequate analgesia without opioids. Opioid prescriptions should be offered sparingly and for no more than 25 MME.

LEVEL OF EVIDENCE

Level II.

TYPE OF STUDY

Prognosis study.

Utility of Fetal Cardiac Axis and Cardiac Position Assessment in Predicting Neonatal Respiratory Morbidity in Fetal Congenital Lung Lesions

OBJECTIVES

To assess the diagnostic performance of the fetal cardiac axis (CA) and/or cardiac position (CP) versus the congenital pulmonary malformation volume ratio (CVR) in predicting any and severe neonatal respiratory morbidity in fetal congenital lung lesions.

METHODS

This work was an 11-year retrospective cohort study. The sensitivity, specificity, positive predictive value, and negative predictive value of CA and/or CP assessment in prediction of respiratory morbidity were calculated before 24 weeks' gestation and between 24 and 32 weeks and compared to CVR cutoffs obtained from the literature.

RESULTS

Fifty-three patients were included. CA and/or CP abnormalities were present in 45% and 38% of patients before 24 weeks and between 24 and 32 weeks and were significantly more common in left- versus right-sided lesions (60% versus 17%; P = .003). The sensitivity, specificity, positive predictive value, and negative predictive value of an abnormal CA and/or CP for any and severe respiratory morbidity were 0.67, 0.61, 0.33, and 0.86 and 0.8, 0.58, 0.17, and 0.97 before 24 weeks and 0.75, 0.73, 0.45, and 0.91 and 0.8, 0.67, 0.20, and 0.97 between 24 and 32 weeks, respectively. An abnormal CA and/or CP had higher sensitivity for any respiratory morbidity compared to the CVR at 0.5 and 0.8 cutoffs both before 24 weeks and between 24 and 32 weeks (P < .05).

CONCLUSIONS

An abnormal CA and/or CP before 24 weeks and between 24 and 32 weeks has higher sensitivity for the detection of any respiratory morbidity at birth compared to the CVR at both 0.5 and 0.8 cutoffs. A normal CA and CP have a high negative predictive value for excluding any respiratory morbidity at birth both before 24 weeks and between 24 and 32 weeks.

Routine postnatal chest x-ray and intensive care admission are unnecessary for a majority of infants with congenital lung malformations

BACKGROUND

Postnatal evaluation of prenatally identified congenital lung malformations (CLMs) often includes a chest x-ray (CXR) and neonatal intensive care unit (NICU) admission for observation. With current efforts aimed at prioritizing value and resource utilization, we sought to assess the utility of this practice in infants with known CLMs. We hypothesized that CXR and NICU admission are overused and could be deferred in the majority of cases.

METHODS

Clinical and radiographic data for infants with CLM from 2007 to 2016 were reviewed with IRB approval. Regression models were developed for respiratory support (RS), symptoms within 30 days of discharge (Sx30), and abnormal CXR. Predictors included initial symptoms (IS), birth weight (BW), gestational age (GA), cyst-volume-ratio (CVR) and abnormal CXR. Odds ratios (ORs) and ROC curves were generated for significant predictors (p < 0.05).

RESULTS

Fifty-eight infants were identified. Eight were excluded because birth or surgery occurred outside of our institution. Another four were excluded for requiring immediate surgery, leaving forty-six for full analysis. All infants underwent initial CXR and NICU admission, and 22 (47.8%) had an abnormal CXR. Higher CVR (OR = 6.69, p = 0.024) and lower BW (OR = 0.27, p = 0.028) both increased the odds of an abnormal CXR. Applying optimal ROC cutoffs for CVR and BW would have safely eliminated 21 of 46 CXRs, increasing CXR sensitivity from 48% to 68%. For RS and Sx30, no variable, including abnormal CXR, significantly predicted outcomes. Twenty-seven infants (59%) had a NICU stay of <24 h and only three patients (6.8%) developed Sx30.

CONCLUSIONS

Both CXR and NICU admission appear to be overused in infants with CLM. CXR result did not predict need for respiratory support or symptoms following discharge, and thus may not aid in the initial evaluation or in the prediction of future care needs. Using CVR and birth weight can guide CXR use and optimize its sensitivity. Need for NICU admission could not be predicted, but a majority of infants spent <24 h in the NICU without intervention, suggesting that NICU admission was likely not needed for all infants in this setting.

LEVEL OF EVIDENCE

Study of diagnostic test, Level II evidence.

Alginate microparticles loaded with basic fibroblast growth factor induce tissue coverage in a rat model of myelomeningocele

BACKGROUND/PURPOSE

We sought to develop a minimally invasive intra-amniotic therapy for prenatal treatment of myelomeningocele (MMC) in an established rat model.

METHODS

Time-dated pregnant rats were gavage-fed retinoic acid to induce MMC. Groups received intraamniotic injections at E17.5 with alginate particles loaded with fluorescent dye, basic fibroblast growth factor (Alg-HSA-bFGF), fluorescently tagged albumin (Alginate-BSA-TR), free bFGF, blank alginate particles (Alg-Blank), or PBS. Groups were analyzed at 3 h for specific particle binding or at term (E21) to determine MMC coverage.

RESULTS

Alginate microparticles demonstrated robust binding to the MMC defect 3 h after injection. Of those specimens analyzed at E21, 150 of 239 fetuses (62.8%) were viable. Moreover, 18 of 61 (30%) treated with Alg-HSA-bFGF showed evidence of soft tissue coverage compared to 0 of 24 noninjected (P = 0.0021), 0 of 13 PBS (P = 0.0297), and 0 of 42 free bFGF (P = P < 0.0001). Scaffolds of aggregated particles associated with disordered keratinized tissue were observed covering the defect in 2 of 18 (11%) Alg-BSA-TR and 3 of 19 (16%) Alg-Blank specimens.

CONCLUSIONS

Injection of microparticles loaded with bFGF resulted in significant soft tissue coverage of the MMC defect compared to controls. Alginate microparticles without growth factors might result in scaffold development over the fetal MMC.

TYPE OF STUDY

Basic science.

LEVEL OF EVIDENCE

N/A.

Opioid Prescribing Habits of General Versus Pediatric Surgeons After Uncomplicated Laparoscopic Appendectomy

BACKGROUND

Adolescents who use prescription opioids have an increased risk for future drug abuse and overdose, making them a high-risk population. Appendectomy is one of the most common surgical procedures in this age group, often requires opioid analgesia, and is performed by both pediatric and general surgeons. Prescription patterns comparing these two provider groups have not yet been evaluated; we hypothesize that general surgery providers prescribe more opioids for adolescent and young adult patients than do pediatric surgery providers.

METHODS

A retrospective chart review was conducted across a single health system consisting of four hospitals. All uncomplicated laparoscopic appendectomies performed between January 1, 2016 and August 14, 2017 on patients aged 7-20 were included for analysis. Any case coded for multiple procedures, identified as converted to open, or had a length of stay >48 h were excluded. The primary outcome measure was amount of opioid prescribed postoperatively. To standardize different formulations and types of analgesia prescribed, prescriptions were converted into oral morphine equivalents (OMEs). For reference, one 5 mg pill of oxycodone equals 7.5 OME. Linear regression was performed controlling for patient weight, gender, race, insurance status, provider type (pediatric versus general surgery), and provider level (resident, advanced practice provider, and attending).

RESULTS

A total of 336 pediatric laparoscopic appendectomies were analyzed, 148 by general surgeons and 188 by pediatric surgeons. Pediatric surgeons prescribed less opioid than general surgeons overall (59 OME versus 90 OME, P < 0.0001). For patients aged <13 y, there was no significant difference between pediatric (26 OME) and general (37 OME, P = 0.8921) surgeons. However, for the age group 13-20 y, pediatric surgeons prescribed 25% less opioid than general surgeons (90 OME versus 112.5 OME, P < 0.0001). Regression analysis demonstrated that being cared for by a general surgery service (+24.1 OME [95% confidence interval 9.8-38.3]) was associated with high prescribing, whereas having Medicaid was associated with lower prescription amounts (-16.4 OME [95% confidence interval -32.5 to -0.3]).

CONCLUSIONS

After an uncomplicated laparoscopic appendectomy, general surgeons prescribe significantly more opioid to adolescent patients than do pediatric surgeons, even when controlling for age and weight. One substantial and modifiable contributor of the opioid epidemic is the amount of opioid prescribed. The variability of prescribing habits to adolescents and young adults demonstrates a clear need for increased education and guidelines on this topic, especially for surgeons who do not frequently treat the younger and more vulnerable population.

In utero nanoparticle delivery for site-specific genome editing

Genetic diseases can be diagnosed early during pregnancy, but many monogenic disorders continue to cause considerable neonatal and pediatric morbidity and mortality. Early intervention through intrauterine gene editing, however, could correct the genetic defect, potentially allowing for normal organ development, functional disease improvement, or cure. Here we demonstrate safe intravenous and intra-amniotic administration of polymeric nanoparticles to fetal mouse tissues at selected gestational ages with no effect on survival or postnatal growth. In utero introduction of nanoparticles containing peptide nucleic acids (PNAs) and donor DNAs corrects a disease-causing mutation in the β-globin gene in a mouse model of human β-thalassemia, yielding sustained postnatal elevation of blood hemoglobin levels into the normal range, reduced reticulocyte counts, reversal of splenomegaly, and improved survival, with no detected off-target mutations in partially homologous loci. This work may provide the basis for a safe and versatile method of fetal gene editing for human monogenic disorders.

Complications in pediatric enteral and vascular access

Obtaining reliable enteral and vascular access constitutes a significant fraction of a pediatric surgeon׳s job. Multiple approaches are available. Given the complicated nature of this patient population multiple complications can also occur. This article discusses the various techniques and potential complications associated with short- and long-term enteral and vascular access.

Life-Long Transgene Expression in Skeletal Muscle Without Transduction of Satellite Cells Following Embryonic Myogenic Progenitor Transduction by Lentivirus Administered in Utero

Embryologic events in mammalian myogenesis remain to be fully defined. Recent evidence supports the presence of a common progenitor arising in the dermomyotome that gives rise to both embryologic and adult muscle and postnatal myogenic stem cells (satellite cells). In this study, we utilize the technique of early intra-amniotic gene transfer to target nascent muscle progenitors as they traverse the primitive streak before formation of the dermomyotome. This technique robustly transduced both epaxial and hypaxial muscle groups. Marker gene expression is observed in up to 100% muscle fibers in the lower extremities and is sustained for the lifetime of the mouse. We next analyzed transduced muscle for satellite cell transduction using highly sensitive methodology. Surprisingly, despite high levels of sustained transgene expression in muscle fibers, satellite cells lacked the marker transgene. Our data suggest that dermatomyotome is a heterogeneous structure and that not all myogenic progenitors of dermatomyotome give rise to satellite cells.

Developmental stage determines efficiency of gene transfer to muscle satellite cells by in utero delivery of adeno-associated virus vector serotype 2/9

Efficient gene transfer to muscle stem cells (satellite cells) has not been achieved despite broad transduction of skeletal muscle by systemically administered adeno-associated virus serotype 2/9 (AAV-9) in mice. We hypothesized that cellular migration during fetal development would make satellite cells accessible for gene transfer following in utero intravascular injection. We injected AAV-9 encoding green fluorescent protein (GFP) marker gene into the vascular space of mice ranging in ages from post-coital day 12 (E12) to postnatal day 1 (P1). Satellite cell transduction was examined using: immunohistochemistry and confocal microscopy, satellite cell migration assay, myofiber isolation and FACS analysis. GFP positive myofibers were detected in all mature skeletal muscle groups and up to 100% of the myofibers were transduced. We saw gestational variation in cardiac and skeletal muscle expression. E16 injection resulted in 27.7 ± 10.0% expression in satellite cells, which coincides with the timing of satellite cell migration, and poor satellite cell expression before and after satellite cell migration (E12 and P1). Our results demonstrate that efficient gene expression is achieved in differentiated myofibers and satellite cells after injection of AAV-9 in utero. These findings support the potential of prenatal gene transfer for muscle based treatment strategies.

Robust in vivo transduction of nervous system and neural stem cells by early gestational intra amniotic gene transfer using lentiviral vector

Presently, in vivo methods to efficiently and broadly transduce all major cell types throughout both the central (CNS) and peripheral adult nervous system (PNS) are lacking. In this study, we hypothesized that during early fetal development neural cell populations, including neural stem cells (NSCs), may be accessible for gene transfer via the open neural groove. To test this hypothesis, we injected lentiviral vectors encoding a green fluorescent protein (GFP) marker gene into the murine amniotic cavity at embryonic day 8. This method (i) efficiently and stably transduced the entire nervous system for at least 80% of the lifespan of the mice, (ii) transduced all major neural cell types, and (iii) transduced adult NSCs of the subventricular zone (SVZ) and subgranular zones (SGZs). This simple approach has broad applications for the study of gene function in nervous system development and adult NSCs and may have future clinical applications for treatment of genetic disorders of the nervous system.

The developmental stage determines the distribution and duration of gene expression after early intra-amniotic gene transfer using lentiviral vectors

Gene transfer after intra-amniotic injection has, in general, been of low efficiency and limited to epithelial cells in the skin, pulmonary and gastrointestinal system. We have recently shown that early gestational administration results in a more efficient gene transfer to developmentally accessible stem cell populations in the skin and eye. In this study we present a comprehensive analysis of patterns of tissue expression seen after early intra-amniotic gene transfer (IAGT) using lentiviral vectors. To assess the influence of developmental stage on tissue expression, injections were administered from the late head fold/early somite stage (E8) to E18. In early gestation (E8-10), green fluorescent protein (GFP) expression was observed in multiple organs, derived from all three germ layers. Remarkably, GFP expression was observed in tissues derived from mesoderm and neural ectoderm at E8, whereas expression was limited to only epithelial cells of ectoderm- and endoderm-derived organs after E11. The amount and duration of gene expression was much higher after IAGT at early gestational time points. The observed temporal patterns of gene expression correspond to the predicted developmental accessibility of organ-specific cell populations. This model may be useful for the analyses of mechanisms of genetic and/or developmental disease and for the development of prenatal gene therapy for specific disorders.

On the effect of covalently appended quinolones on termini of DNA duplexes

Quinolones are gyrase inhibitors that are widely used as antibiotics in the clinic. When covalently attached to oligonucleotides as 5'-acylamido substituents, quinolones were found to stabilize duplexes of oligonucleotides against thermal denaturation. For short duplexes, such as qu-T*GCGCA, where qu is a quinolone residue and T is a 5'-amino-5'-deoxythymidine residue, an increase in the UV melting point of up to 27.8 degrees C was measured. The stabilizing effect was demonstrated for all quinolones tested, namely nalidixic acid, oxolinic acid, pipemidic acid, cinoxacin, norfloxacin, and ofloxacin. The three-dimensional structure of (oa-T*GCGCA)2, where oa is an oxolinic acid residue, was solved by two-dimensional NMR spectroscopy and restrained molecular dynamics. In this complex, the oxolinic acid residues disrupt the terminal T1:A6 base pairs and stack on the G2:C5 base pairs. The displaced adenosine residues bind in the minor groove of the core duplex, while the thymidine residues pack against the oxolinic acid residues. The "molecular cap" thus formed fits tightly on the G:C base pairs, resulting in increased base-pairing fidelity, as demonstrated in UV melting experiments with the sequence oa-T*GGTTGAC and target strands containing a mismatched nucleobase. The structure of the "molecular cap" with its disrupted terminal base pair may also be helpful for modeling how quinolones block re-ligation of DNA strands in the active site of gyrases.