Fetal bradycardia in open versus fetoscopic prenatal repair of spina bifida.

OBJECTIVE: To compare the occurrence of fetal bradycardia in open versus fetoscopic fetal spina bifida surgery. METHODS: This is a single-institution retrospective cohort study of patients undergoing open (n = 25) or fetoscopic (n = 26) spina bifida repair between 2017 and 2022. From October 2017 to June 2020, spina bifida repairs were performed via an open classical hysterotomy, and from November 2020 to June 2022 fetoscopic repairs were performed following transition to this technique. Fetal heart rate (FHR) in beats per minute (bpm) was recorded via echocardiography every 15 min during the procedure. Cohort characteristics, fetal bradycardia and maternal physiologic parameters were compared between the groups. RESULTS: Fetuses undergoing an open repair more frequently developed bradycardia defined as <110 bpm (32% vs. 3.8%, p = 0.008), and a trend was observed for FHR decreases more than 25 bpm from baseline (20% vs. 3.8%, p = 0.073). Profound bradycardia less than 80 bpm was rare, occurring in only three operations (two in open, one in fetoscopic repair) with two fetuses (one in each group) requiring emergency cesarean delivery. CONCLUSION: When compared to open fetal surgery, fetal bradycardia occurred less frequently in fetoscopic surgery despite a significantly greater anesthetic exposure and the use of the intraamniotic carbon dioxide insufflation.

Needle Fetal Thoracoscopy: A Technique to Assist with Ultrasound-Guided Placement of Challenging Thoracoamniotic Shunts.

INTRODUCTION: Fetal thoracoamniotic shunts are common lifesaving interventions but frequently require replacement. Needle fetal thoracoscopy is a technique that uses standard thoracoamniotic shunt introducer sheaths to permit direct visualization and even instrument manipulation during shunt deployment to facilitate optimal positioning and primary shunt function in the most challenging cases. CASE PRESENTATION: In this study, 5 patients who underwent needle fetal thoracoscopy-assisted thoracoamniotic shunt placement were reviewed. Three patients with large, macrocystic congenital pulmonary airway malformations (CPAMs) with evidence of worsening mediastinal shift and/or hydrops and 2 patients with large chylothorax with fetal hydrops were treated. Four cases had previous shunts that failed due to poor sonographic visualization during initial placement, cyst septations, shunt obstruction, or dislodgment. Needle fetal thoracoscopy was used to disrupt cyst walls and septations, clear hematoma, and confirm the optimal initial position of the shunt. In this series, 1 severe CPAM patient with a short cervix developed preterm labor postoperatively resulting in neonatal demise. The remaining 4 patients experienced resolution of hydrops and progressed to successful delivery with excellent neonatal outcomes. CONCLUSION: Needle fetal thoracoscopy is a procedure that may be selectively deployed in challenging thoracoamniotic shunt cases impacted by recurrent failure, poor sonographic windows, and challenging fetal positioning.

Ex-Utero Intrapartum Treatment-to-Airway for Obstructing Fetal Neck Masses: A Singular Methodology for Monochorionic and Dichorionic Twin Pregnancies.

Fetal airway obstruction in one twin of a diamniotic pregnancy presents unique challenges. Very few cases of ex-utero-intrapartum-treatment (EXIT) procedures for twin pregnancy have been reported and only in dichorionic pregnancies. We report a singular methodology for EXIT-to-airway procedures in two pregnancies involving monochorionic and dichorionic twins. Two cases of EXIT-to-airway in twin pregnancies were performed in 2018 and 2019 at a regional fetal treatment center. Case 1 involved a giant cervical teratoma in a monochorionic-diamniotic twin pregnancy with preterm labor at 29 weeks. Case 2 involved a dichorionic-diamniotic pregnancy with a large cervical lymphatic malformation with preterm labor at 36 weeks. In each case, the polyhydramnios caused the affected twin's amniotic sac to be the presenting sac for the surgical approach. Bronchoscopy and successful intubation was completed after 22 and 10 minutes of uteroplacental bypass, respectively. The bystander twins were delivered second without intubation and resuscitated without perinatal distress. EXIT-to-airway appears to be a reasonable option for twins including monochorionic pregnancies, via delivery of the affected twin first followed by delivery of the bystander twin. Thoughtful preparation and counseling by an experienced multidisciplinary team permits an EXIT-to-airway approach for twin pregnancies even in an emergent setting.

Nonparasitic Splenic Cysts in Children: Outcomes after Sclerotherapy or Surgical Resection as Initial Management.

Management of splenic cysts in children remains undefined. Sclerotherapy is an innovative, less invasive treatment. This study examined the safety and preliminary effectiveness of sclerotherapy for splenic cysts in children compared with those of surgical treatment. A retrospective review of pediatric patients treated for nonparasitic splenic cysts from 2007 to 2021 was performed at a single institution. Posttreatment outcomes for patients who underwent either expectant management, sclerotherapy, or surgery were reviewed. Thirty patients aged between 0 and 18 years met the inclusion criteria. Cysts in 3 of 8 patients who underwent sclerotherapy were either unresolved or recurred. Patients who underwent sclerotherapy and required surgery for residual symptomatic cyst had an initial cyst diameter of >8 cm. Symptoms resolved in 5 of 8 patients who underwent sclerotherapy, with a significantly reduced cyst size compared with that in patients with continued symptoms who underwent sclerotherapy (61.4% vs 7.0%, P = .01). Sclerotherapy is an effective treatment for splenic cysts, particularly those measuring <8 cm. However, surgical excision may be preferable for large cysts.

CD4 and IL-2 mediated NK cell responses after COVID-19 infection and mRNA vaccination in adults.

A detailed understanding of protective immunity against SARS-CoV-2 is incredibly important in fighting the pandemic. Central to protective immunity is the ability of the immune system to recall previous exposures. Although antibody and T cell immunity have gained considerable attention, the contribution of the NK cell compartment to immune recall and protection from SARS-CoV-2 has not been explored. In this study, we investigate the NK cell responses to stimulation with SARS-CoV-2 in previously exposed and non-exposed individuals. We show that NK cells demonstrate an enhanced CD4+ T cell dependent response when re-exposed to SARS-CoV-2 antigen. The enhanced response is dependent on T cells and correlates with the number of SARS-CoV-2 specific CD4 T cells. We find that IL-2 is a critical mediator of NK cell function. These findings suggest that NK cells contribute to the protective responses against SARS-CoV-2 through a cooperation with antigen-specific CD4 T cells and have significant implications on our understanding of protective immunity in SARS-CoV-2.

Selective Fetoscopic Laser Photocoagulation or Expectant Management for Stage I Twin-Twin Transfusion: A Cost-Effectiveness Analysis.

BACKGROUND: Selective fetoscopic laser photocoagulation (SFLP) is the preferred intervention for stage II-IV twin-twin transfusion syndrome (TTTS); however, there is no consensus on whether SFLP or expectant management (EM) is the preferred strategy to manage Quintero stage I TTTS. OBJECTIVE: The objective of this study is to estimate whether SFLP or EM is the cost-effective strategy for management of Quintero stage I TTTS. STUDY DESIGN: A decision-analysis (DA) model compared SFLP to EM for 1,000 pregnant people with monochorionic-diamniotic twins affected by stage I TTTS. All subjects were assumed to be appropriate candidates for either SFLP or EM. Probabilities, costs, and utilities were derived from the literature. The DA was conducted from a healthcare payor perspective, and the analytic horizon was over the course of an offspring's lifetime, with primary outcomes of survivorship (i.e., no intrauterine fetal demise or neonatal death) and long-term neurodevelopmental impairment. The model incorporated Markov processes with 4-week cycles throughout pregnancy. Incremental cost-effectiveness ratios (ICER) for each strategy were calculated and compared to estimate marginal cost effectiveness. An ICER of USD 100,000 per quality-adjusted life year was used to define the cost-effectiveness threshold. One-way sensitivity and Monte Carlo analyses (MCA), as well as microsimulations, were performed. RESULTS: For base-case estimates, SFLP was found to be cost-effective compared to EM in the management of stage I TTTS. In one-way sensitivity analysis, varying each variable along pre-specified ranges did not result in changes in the conclusion. MCA projects SFLP as the cost-effective strategy in 100% of runs. CONCLUSIONS: With base-case estimates, SFLP is estimated to be the cost-effective strategy for the treatment of Quintero stage I TTTS when compared with EM. This remained true across a wide range of inputs.

The interplay between prenatal liver growth and lung development in congenital diaphragmatic hernia.

Objective: Liver herniation is a known risk factor for increased severity in CDH and is associated with clinically significant pulmonary hypoplasia and pulmonary hypertension. Better studies are needed to understand the growth of the herniated liver compared to the liver that remains in the abdomen and how this liver growth then affects lung development. Serial hi-resolution fetal MRI enables characterization of liver growth throughout gestation and examination of macroscopic features that may regulate liver growth. Here, we hypothesized that the nature of liver herniation affects liver growth and, in turn, affects lung growth. Methods: Clinical data were retrospectively collected from consecutive cases of prenatally diagnosed isolated left-sided or right-sided CDH from June 2006 to August 2021. Only those cases with MRI lung volumetry for both mid-gestation and late-gestation time points were recruited for analysis. Cases with fetal chromosomal abnormalities and other major structural abnormalities were excluded. Fractional liver volume and liver growth was indexed to estimated fetal weight and compared to lung growth. Results: Data was collected from 28 fetuses with a left liver-down CDH (LLD), 37 left liver-up CDH (LLU) and 9 right liver-up CDH (RLU). Overall, RLU fetuses had greater overall and fractional (intra-thoracic vs. intra-abdominal) liver growth when compared to LLD and LLU fetuses. Additionally, intra-thoracic liver growth was consistently slower than intra-abdominal liver growth for either right- or left-sided CDH. When the liver was not herniated, a positive correlation was seen between liver growth and lung growth. However, when the liver was herniated above the diaphragm, this positive correlation was lost. Conclusion: Right-sided CDH fetuses exhibit greater liver growth compared to left-sided CDH. Liver herniation disrupts the normal positive correlation between liver and lung growth that is seen when the liver is entirely within the abdomen.

Cell necrosis, intrinsic apoptosis and senescence contribute to the progression of exencephaly to anencephaly in a mice model of congenital chranioschisis.

Exencephaly/anencephaly is one of the leading causes of neonatal mortality and the most extreme open neural tube defect with no current treatments and limited mechanistic understanding. We hypothesized that exencephaly leads to a local neurodegenerative process in the brain exposed to the amniotic fluid as well as diffuse degeneration in other encephalic areas and the spinal cord. To evaluate the consequences of in utero neural tissue exposure, brain and spinal cord samples from E17 exencephalic murine fetuses (maternal intraperitoneal administration of valproic acid at E8) were analyzed and compared to controls and saline-injected shams (n = 11/group). Expression of apoptosis and senescence genes (p53, p21, p16, Rbl2, Casp3, Casp9) was determined by qRT-PCR and protein expression analyzed by western blot. Apoptosis was measured by TUNEL assay and PI/AV flow cytometry. Valproic acid at E8 induced exencephaly in 22% of fetuses. At E17 the fetuses exhibited the characteristic absence of cranial bones. The brain structures from exencephalic fetuses demonstrated a loss of layers in cortical regions and a complete loss of structural organization in the olfactory bulb, hippocampus, dental gyrus and septal cortex. E17 fetuses had reduced expression of NeuN, GFAP and Oligodendrocytes in the brain with primed microglia. Intrinsic apoptotic activation (p53, Caspase9 and 3) was upregulated and active Caspase3 localized to the layer of brain exposed to the amniotic fluid. Senescence via p21-Rbl2 was increased in the brain and in the spinal cord at the lamina I-II of the somatosensory dorsal horn. The current study characterizes CNS alterations in murine exencephaly and demonstrates that degeneration due to intrinsic apoptosis and senescence occurs in the directly exposed brain but also remotely in the spinal cord.

A Newborn With Abdominal Pain.

A previously healthy 3-week-old boy presented with 5 hours of marked fussiness, abdominal distention, and poor feeding. He was afebrile and well perfused. His examination was remarkable for localized abdominal tenderness and distention. He was referred to the emergency department in which an abdominal radiograph revealed gaseous distention of the bowel with a paucity of gas in the pelvis. Complete blood cell count and urinalysis were unremarkable. His ongoing fussiness and abnormal physical examination prompted consultation with surgery and radiology. Our combined efforts ultimately established an unexpected diagnosis.

Extrinsic allospecific signals of hematopoietic origin dictate iNKT cell lineage-fate decisions during development.

Invariant NKT (iNKT) cells are critical to the maintenance of tolerance toward alloantigens encountered during postnatal life pointing to the existence of a process for self-education. However, the impact of developmentally encountered alloantigens in shaping the phenotype and function of iNKT cells has not been described. To better understand this process, the current report examined naïve iNKT cells as they matured in an allogeneic environment. Following the prenatal transfer of fetal hematopoietic cells between age-matched allogeneic murine fetuses, cell-extrinsic signals appeared to dictate allospecific patterns of Ly49 receptor expression and lineage diversity in developing iNKT cells. Regulation for this process arose from cells of hematopoietic origin requiring only rare exposure to facilitate broad changes in developing iNKT cells. These findings highlight surprisingly asymmetric allospecific alterations in iNKT cells as they develop and mature in an allogeneic environment and establish a new paradigm for study of the self-education of iNKT cells.

Tolerance to noninherited maternal antigens, reproductive microchimerism and regulatory T cell memory: 60 years after 'Evidence for actively acquired tolerance to Rh antigens'.

Compulsory exposure to genetically foreign maternal tissue imprints in offspring sustained tolerance to noninherited maternal antigens (NIMA). Immunological tolerance to NIMA was first described by Dr. Ray D. Owen for women genetically negative for erythrocyte rhesus (Rh) antigen with reduced sensitization from developmental Rh exposure by their mothers. Extending this analysis to HLA haplotypes has uncovered the exciting potential for therapeutically exploiting NIMA-specific tolerance naturally engrained in mammalian reproduction for improved clinical outcomes after allogeneic transplantation. Herein, we summarize emerging scientific concepts stemming from tolerance to NIMA that includes postnatal maintenance of microchimeric maternal origin cells in offspring, expanded accumulation of immune suppressive regulatory T cells with NIMA-specificity, along with teleological benefits and immunological consequences of NIMA-specific tolerance conserved across mammalian species.

Prenatal Allogeneic Tolerance in Mice Remains Stable Despite Potent Viral Immune Activation.

Transplanting stem cells before birth offers an unparalleled opportunity to initiate corrective treatment for numerous childhood diseases with minimal or no host conditioning. Although long-term engraftment has been demonstrated following in utero hematopoietic cellular transplantation during immune quiescence, it is unclear if prenatal tolerance becomes unstable with immune activation such as during a viral syndrome. Using a murine model of in utero hematopoietic cellular transplantation, the impact of an infection with lymphocytic choriomeningitis virus on prenatal allospecific tolerance was examined. The findings in this report illustrate that established mechanisms of donor-specific tolerance are strained during potent immune activation. Specifically, a transient reversal in the anergy of alloreactive lymphocytes is seen in parallel with the global immune response toward the virus. However, these changes return to baseline following resolution of the infection. Importantly, prenatal engraftment remains stable during and after immune activation. Collectively, these findings illustrate the robust nature of allospecific tolerance in prenatal mixed chimerism compared with models of postnatal chimerism and provides additional support for the prenatal approach to the treatment of congenital benign cellular disease.

Angiopoietin-1 improves endothelial progenitor cell-dependent neovascularization in diabetic wounds.

BACKGROUND: The diabetic phenotype of wound healing is in part characterized by impaired neovascularization and deficient endothelial progenitor cell (EPC) recruitment. Angiopoietin-1 (Ang-1) is a potent mobilizer of EPCs from the bone marrow (BM). A suggested mechanism for EPC mobilization from the BM is mediated by matrix metalloproteinase 9 (MMP-9) and stem cell factor (SCF). Taken together, we hypothesized that overexpression of Ang-1 in diabetic wounds will recruit EPCs and improve neovascularization and wound healing. METHODS: An endothelial lineage BM-labeled murine model of diabetes was developed to track BM-derived EPCs. FVBN mice were lethally irradiated and then reconstituted with BM from syngeneic Tie2/LacZ donor mice. Diabetes was induced with streptozotocin. Dorsal wounds in BM-transplanted mice were treated with Ad-Ang-1, Ad-GFP, or phosphate-buffered saline. At day 7 after injury, wounds were harvested and analyzed. A similar experiment was conducted in EPC mobilization deficient MMP-9 -/- mice to determine whether the effects of Ang-1 were EPC-dependent. RESULTS: Overexpression of Ang-1 resulted in greatly improved re-epithelialization, neovascularization, and EPC recruitment in diabetic BM-transplanted wounds at day 7. Ang-1 treatment resulted in increased serum levels of proMMP-9 and SCF but had no effect on vascular endothelial growth factor levels. According to our FACS results, peripheral blood EPC (CD34(+)/Cd133(+)/Flk1(+)) counts at day 3 after wounding showed impaired EPC mobilization in MMP-9 -/- mice compared with those of wild-type controls. EPC mobilization was rescued by SCF administration, validating this model for EPC-mobilization-deficient mechanistic studies. In MMP-9 -/- mice, Ad-Ang-1 accelerated re-epithelialization in a similar manner, but had no effect on neovascularization. CONCLUSION: Our results show that Ang-1 administration results in improved neovascularization which is dependent on EPC recruitment and has direct effects on wound re-epithelialization. These data may represent a novel strategy to correct the phenotype of impaired diabetic neovascularization and may improve diabetic wound healing.

Cross-Generational Reproductive Fitness Enforced by Microchimeric Maternal Cells.

Exposure to maternal tissue during in utero development imprints tolerance to immunologically foreign non-inherited maternal antigens (NIMA) that persists into adulthood. The biological advantage of this tolerance, conserved across mammalian species, remains unclear. Here, we show maternal cells that establish microchimerism in female offspring during development promote systemic accumulation of immune suppressive regulatory T cells (Tregs) with NIMA specificity. NIMA-specific Tregs expand during pregnancies sired by males expressing alloantigens with overlapping NIMA specificity, thereby averting fetal wastage triggered by prenatal infection and non-infectious disruptions of fetal tolerance. Therefore, exposure to NIMA selectively enhances reproductive success in second-generation females carrying embryos with overlapping paternally inherited antigens. These findings demonstrate that genetic fitness, canonically thought to be restricted to Mendelian inheritance, is enhanced in female placental mammals through vertically transferred maternal cells that promote conservation of NIMA and enforce cross-generational reproductive benefits.

Prenatal Allospecific NK Cell Tolerance Hinges on Instructive Allorecognition through the Activating Receptor during Development.

Little is known about how the prenatal interaction between NK cells and alloantigens shapes the developing NK cell repertoire toward tolerance or immunity. Specifically, the effect on NK cell education arising from developmental corecognition of alloantigens by activating and inhibitory receptors with shared specificity is uncharacterized. Using a murine prenatal transplantation model, we examined the manner in which this seemingly conflicting input affects NK cell licensing and repertoire formation in mixed hematopoietic chimeras. We found that prenatal NK cell tolerance arose from the elimination of phenotypically hostile NK cells that express an allospecific activating receptor without coexpressing any allospecific inhibitory receptors. Importantly, the checkpoint for the system appeared to occur centrally within the bone marrow during the final stage of NK cell maturation and hinged on the instructive recognition of allogeneic ligand by the activating receptor rather than through the inhibitory receptor as classically proposed. Residual nondeleted hostile NK cells expressing only the activating receptor exhibited an immature, anergic phenotype, but retained the capacity to upregulate inhibitory receptor expression in peripheral sites. However, the potential for this adaptive change to occur was lost in developmentally mature chimeras. Collectively, these findings illuminate the intrinsic process in which developmental allorecognition through the activating receptor regulates the emergence of durable NK cell tolerance and establishes a new paradigm to fundamentally guide future investigations of prenatal NK cell-allospecific education.

Differential patterns of prenatal ipsilateral and contralateral lung growth in cases of isolated left-sided congenital diaphragmatic hernia.

OBJECTIVE: The aim of this research was to compare the impact of varying degrees of visceral herniation on the growth rates of the contralateral and ipsilateral fetal lungs in cases of isolated left-sided congenital diaphragmatic hernia (CDH). METHODS: Data were retrieved from 58 fetuses with isolated left-sided CDH undergoing magnetic resonance imaging studies at both mid-gestation (20-30 weeks) and late-gestation (>30 weeks) time points. The growth of the right and left lungs (ΔLV-R and ΔLV-L) was calculated. The impact of the degree of visceral herniation on the growth disparity between the right and left lungs was then compared. RESULTS: Measurable growth occurred in both lungs between the mid-gestation and late-gestation time points in each group. The ΔLV-R exhibited a strong correlation with ΔLV-L. However, the right lung grew significantly faster than the left lung (ΔLV-R = 1.36 vs ΔLV-L = 0.17 mL/week, P < 0.001). A higher degree of visceral herniation appeared to decrease the growth rate disparity by progressive limitation of the growth of the right lung. CONCLUSION: The contralateral lung retains the potential to grow faster than the ipsilateral lung during the third trimester. A higher degree of visceral herniation places progressive limitations on contralateral lung growth thereby diminishing the growth rate disparity between the right and left lungs.

NK cell tolerance as the final endorsement of prenatal tolerance after in utero hematopoietic cellular transplantation.

The primary benefits of in utero hematopoietic cellular transplantation (IUHCT) arise from transplanting curative cells prior to the immunologic maturation of the fetus. However, this approach has been routinely successful only in the treatment of congenital immunodeficiency diseases that include an inherent NK cell deficiency despite the existence of normal maternal immunity in either setting. These observations raise the possibility that fetal NK cells function as an early barrier to allogeneic IUHCT. Herein, we summarize the findings of previous studies of prenatal NK cell allospecific tolerance in mice and in humans. Cumulatively, this new information reveals the complexity of the fetal immune response in the setting of rejection or tolerance and illustrates the role for fetal NK cells in the final endorsement of allospecific prenatal tolerance.

What does it take to be a successful pediatric surgeon-scientist?

BACKGROUND: The factors that contribute to success as a pediatric surgeon-scientist are not well defined. The purpose of this study is to define a group of NIH-funded pediatric surgeons, assess their academic productivity, and elucidate factors that have contributed to their success. METHODS: Pediatric surgeons were queried in the NIH report database to determine NIH funding awarded. Academic productivity was then assessed. An online survey was then targeted to NIH-funded pediatric surgeons. RESULTS: Since 1988, 83 pediatric surgeon-investigators have received major NIH funding. Currently, there are 37 pediatric surgeons with 43 NIH-sponsored awards. The mean h-index of this group of pediatric surgeons was 18 ± 1.1, mean number of publications (since 2001) was 21 ± 2.1, and both increase commensurate with academic rank. In response to the survey, 81% engaged in research during their surgical residency, and 48% were mentored by a pediatric surgeon-scientist. More than 60% of respondents had significant protected time and financial support. Factors felt to be most significant for academic success included mentorship, perseverance, and protected time. CONCLUSIONS: Mentorship, perseverance, institutional commitment to protected research time, and financial support are considered to be important to facilitate the successes of pediatric surgeon-scientists. These results will be useful to aspiring pediatric surgeon-scientists and departments wishing to develop a robust research program.

Expanded intrathoracic space in fetal cases of isolated congenital diaphragmatic hernia contributes to disparity between percent predicted lung volume and observed to expected total lung volume.

OBJECTIVE: The aim of this study was to determine whether fetal lung volume and visceral herniation are associated with changes in intrathoracic space in congenital diaphragmatic hernia(CDH). METHODS: We retrospectively examined the relationship between magnetic resonance imaging-derived measurements of intrathoracic space [predicted lung volume (PLV)] and residual lung volume or visceral herniation among isolated left-sided CDH fetuses. RESULTS: Data from fetal magnetic resonance imaging studies of 60 isolated left-sided CDH cases were analyzed. The median PLV of the CDH fetuses was found to be much greater than the expected total lung volume (eTLV) of a normal fetus at the same gestational age. Surprisingly, liver herniation and observed TLV(oTLV) were positively correlated with the PLV. Although the PPLV was consistently less than the o/eTLV, both indices were greater in survivors than in non-survivors, whereas no significant difference was seen in the PLV/eTLV ratio in regard to survivorship. CONCLUSION: The intrathoracic domain available for lungs and viscera is expanded in CDH fetuses and positively affected by the lung volume and the presence of liver herniation, leading to the difference in the PPLV and o/eTLV. Future study of intrathoracic space as it relates to the growth of the lung and herniated viscera is needed to better characterize the relationship between these parameters.