Perinatal Vaccination by Transamniotic Fetal mRNA Delivery: Immunization Against Human Cytomegalovirus in a Rodent Model.

PURPOSE: Gestational cytomegalovirus (CMV) infection is a prevalent disease with significant fetal and neonatal morbidity. MRNA vaccines have emerged as powerful options for postnatal immunization against infections. It has been shown that mRNA delivered into the amniotic fluid reaches the fetal circulation via the placenta. We investigated whether transamniotic mRNA delivery could be a viable strategy for perinatal CMV immunization, first utilizing a rodent model. METHODS: Pregnant Sprague Dawley dams underwent volume-matched intra-amniotic injections in all their fetuses (n = 103) of either human CMV (hCMV) envelope glycoprotein B (hCMV-gB) antigen mRNA encapsulated in lipopolyplex (mRNA group; n = 56), or of the same lipopolyplex without mRNA (controls; n = 47) on gestational day 17 (E17; term = E21-22). Term placentas were screened for host production of hCMV-gB by protein immunoblotting. Serum hCMV-gB IgG antibodies were measured at term, and 7 (P7) and 14 (P14) days after birth by ELISA. RESULTS: Overall fetal/neonatal survival was 86 % (89/103). Immunoblotting showed hCMV-gB presence in term mRNA placentas (p = 0.008 vs. controls). No hCMV-gB IgG was detected in the serum of term fetuses (4 days following transamniotic delivery). However, significantly increased serum hCMV-gB IgG levels were present in mRNA pups at P7 (p = 0.008) and P14 (p = 0.006) when controlled by mRNA-free injections (11-19 days after transamniotic administration). CONCLUSIONS: Transamniotic fetal mRNA delivery of a human cytomegalovirus antigen can induce a humoral immune response extending into the neonatal period in a healthy rat model. Fetal mRNA vaccination via the minimally invasive transamniotic route may become a practical strategy for the prevention of perinatal infections. LEVEL OF EVIDENCE: N/A (animal and laboratory study). TYPE OF STUDY: Animal and Laboratory Study.

Longitudinal Assessment of T1 Mapping Trends Disease in Pediatric Patients With Heart Transplant.

BACKGROUND: Surveillance for heart transplant rejection by endomyocardial biopsy is invasive and may yield false negatives. T1 and T2 mapping from cardiac magnetic resonance can demonstrate elevations with rejection. We sought to evaluate longitudinal changes in T1 and T2 mapping in pediatric patients with heart transplant. METHODS AND RESULTS: A cohort study was performed of pediatric patients with heart transplant who underwent concurrent endomyocardial biopsy and cardiac magnetic resonance with T1 and T2 mapping from December 2019 to July 2024. Segmental values were measured and subsegmental elevations (ie, hotspots) were identified. Subjects were categorized as either treated rejection or no rejection. Peak and mean T1 and T2 values and number of hotspots at/between each time point for patient dyads were compared between the groups. A total of 21 subjects (7 treated rejection, 14 no rejection) with 68 total encounters met inclusion criteria. Peak and mean T1 values were higher in treated rejection patients during the rejection period and decreased with treatment (peak, 1086 versus 1052; mean, 1028 versus 1021), such that at last follow-up when their rejection had resolved, there was no significant difference in values when compared with no rejection patients (peak, 1066; mean, 1016). The number of T1 hotspots decreased after rejection treatment (2 versus 1). There were no changes in peak or mean T2 values in the treated rejection group despite treatment, and peak and mean T2 values were similar to patients with no rejection through last follow-up. CONCLUSIONS: Elevated T1 values and hotspots observed during cardiac allograft rejection decline in response to treatment. Cardiac magnetic resonance may serve as a noninvasive monitoring tool for the development and resolution of rejection, as well as the effectiveness of rejection therapy.

Transamniotic Delivery of Surfactant Protein B mRNA in a Healthy Model.

INTRODUCTION: We sought to determine whether exogenous surfactant protein B (SPB) mRNA could be incorporated and translated by the fetal lung after simple transamniotic administration. METHODS: Fetuses (n = 149) of twelve time-dated dams underwent intra-amniotic injections of either human SPB (hSPB) mRNA encapsulated into lipopolyplex (mRNA, n = 99) or lipopolyplex without mRNA (control; n = 50) on gestational day 17 (E17, term = E21-22). Lungs were screened for hSPB by enzyme-linked immunosorbent assay daily until term. Phosphatidylcholine (PC) (a surrogate for surfactant production) was measured in the amniotic fluid by fluorometric assay. Statistical analysis included nonparametric Wilcoxon rank sum test. RESULTS: Significantly improved survival in the mRNA group compared to controls was observed at E18 (100% vs. 85.7%) and E20 (100% vs. 83.3%) (both p < 0.001). When controlled by mRNA-free injections, hSPB protein was detected in the mRNA group's lungs at E18, 19, and term (p = 0.002 to <0.001). Amniotic fluid PC levels were increased compared to control at term [285.9 (251.1, 363.9) µM versus 263.1 (222.8, 309.1) µM]; however, this did not reach significance (p = 0.33). CONCLUSIONS: Encapsulated exogenous SPB mRNA can be incorporated and translated by fetal lung cells following intra-amniotic injection in a healthy rat model. Transamniotic mRNA delivery could become a novel strategy for perinatal surfactant protein replacement.

Transamniotic Fetal Immunotherapy with Secretory IgA: A Potential Novel Ancillary Strategy for the Prevention of Necrotizing Enterocolitis.

INTRODUCTION: Secretory immunoglobulin-A (SIgA), which is not produced perinatally, binds bacteria enhancing mucosal immunity. Higher levels of intestinal bacteria bound by SIgA are protective against necrotizing enterocolitis. Transamniotic fetal immunotherapy (TRAFIT) has previously been used to deliver SIgA to the fetal digestive tract, however, with unclear functional impact. We sought to determine whether SIgA administered via TRAFIT could functionally bind intestinal bacteria postnatally. METHODS: Fetuses (n = 38) from 4 dams underwent intra-amniotic injections of human SIgA on gestational day 19 (E19; term = E22-E23). After spontaneous delivery, pups were survived for 1-2 days postnatally before intestinal contents were procured and submitted to flow cytometry. Specimens were stained for bacteria (Syto-GFP) and human SIgA (PE) to prevent cross-reactivity with maternal rat SIgA. RESULTS: Overall survival was 94.7% (36/38). SIgA-bacterial complexes were identified in all samples at all time points showing significantly higher positive PE events than unstained controls (p = 0.03-0.05). The proportion of bacteria bound by IgA decreased daily, from 45.6% to 29.9% bound at 4-6 days post-TRAFIT, respectively (overall p = 0.05). CONCLUSIONS: TRAFIT with secretory IgA leads to functionally IgA-bound bacteria into the postnatal period and may be a novel strategy for enhancing early mucosal immunity, potentially protecting the neonate against necrotizing enterocolitis.

Universal high-throughput image quantification of subcellular structure dynamics and spatial distributions within cells.

Image analysis of subcellular structures and biological processes relies on specific, context-dependent pipelines, which are labor-intensive, constrained by the intricacies of the specific biological system, and inaccessible to broader applications. Here we introduce the application of dispersion indices, a statistical tool traditionally employed by economists, to analyze the spatial distribution and heterogeneity of subcellular structures. This computationally efficient high-throughput approach, termed GRID (Generalized Readout of Image Dispersion), is highly generalizable, compatible with open-source image analysis software, and adaptable to diverse biological scenarios. GRID readily quantifies diverse structures and processes to include autophagic puncta, mitochondrial clustering, and microtubule dynamics. Further, GRID is versatile, applicable to both 2D cell cultures and 3D multicellular organoids, and suitable for high-throughput screening and performance metric measurements, such as half-maximal effective concentration (EC50) values. The approach enables mechanistic analysis of critical subcellular structure processes of relevance for diseases ranging from metabolic and neuronal diseases to cancer as well as a first-pass screening method for identifying biologically active agents for drug discovery. Statement of Significance: Current methods for image analysis in microscopy are tailored to specific biological contexts, which creates challenges in implementation and efficiency for researchers studying a diverse range of subcellular processes. Our application of dispersion indices, traditionally used in economics, offers a universal framework for high throughput quantification of biological structures, enabling easier and more consistent analysis across various biological contexts. By transforming pixel intensity and count into meaningful statistical measures, our method simplifies the quantification of subcellular structures such as autophagic puncta, microtubule dynamics, and mitochondrial clustering. This approach accelerates the quantitative analysis of sub-cellular processes in disease as well as imaged-based drug discovery. Classification: Bioengineering, Cell Biology, Applied Biological Sciences.

Fetal Vertebral Chondrostasis-Significance of Excessive Cartilage in Vertebral Bodies of Newborns.

INTRODUCTION: We describe an abnormality in fetal and neonatal vertebral bodies whose most conspicuous characteristic is an increase in cartilaginous matrix within cancellous osseous trabeculae. We have termed this finding fetal chondrostasis (FC). METHODS: We initiated a retrospective review of autopsy reports in which this condition had been prospectively diagnosed during a 36-year period. The Chalkley point counting method was applied to histologic sections of vertebral bodies to assess the relative components of cartilage, bone, and bone marrow. The results were compared to those of three control groups whose causes of death were prematurity, birth trauma, and infection. RESULTS: We found that on average, the cartilaginous content in the FC group was considerably greater in both preterm and term infants when compared to controls. FC seemed to evolve from diminished activity in the cartilaginous growth zone resulting in formation of excessively broad cartilaginous columns. These subsequently suffered from delayed resorption following their incorporation within cancellous bony trabeculae. CONCLUSION: Excess cartilage within cancellous bone of vertebral centra in newborns is merely one aspect of disturbed intrauterine osseous development but is seemingly more readily discernible than other features at this site. The most common clinical correlates for FC were multiple congenital anomalies, congenital heart disease, intrauterine growth retardation, prematurity, and certain maternal factors.

Five steps in performing machine learning for binary outcomes.

BACKGROUND: The use of machine learning (ML) in cardiovascular and thoracic surgery is evolving rapidly. Maximizing the capabilities of ML can help improve patient risk stratification and clinical decision making, improve accuracy of predictions, and improve resource utilization in cardiac surgery. The many nuances and intricacies of ML modeling need to be understood to appropriately implement these technologies in the clinical research setting. This primer provides an educational framework of ML for generating predicted probabilities in clinical research and illustrates it with a real-world clinical example. METHODS: We focus on modeling for binary classification and imbalanced classes, a common scenario in cardiothoracic surgery research. We present a 5-step strategy for successfully harnessing the power of ML and performing such analyses, and demonstrate our strategy using a real-world example based on data from the National Surgical Quality Improvement Program pediatric database. CONCLUSIONS: Collaboration among surgeons, care providers, statisticians, data scientists, and information technology professionals can help to maximize the impact of ML as a powerful tool in cardiac surgery.

Operative and nonoperative outcomes in patients with trisomy 13 and 18 with congenital heart disease.

Objective: To evaluate the short- and long-term outcomes of cardiac repair versus nonoperative management in patients with trisomy 13 and trisomy 18 with congenital heart disease. Methods: An institutional review board-approved, retrospective review was undertaken to identify all patients admitted with trisomy 13/18 and congenital heart disease. Patients were divided into 2 cohorts (operated vs nonoperated) and compared. Results: Between 1985 and 2023, 62 patients (34 operated and 28 nonoperated) with trisomy 13 (n = 9) and trisomy 18 (n = 53) were identified. The operated cohort was 74% girls, underwent mainly The Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery mortality category 1 procedures (n = 24 [71%]) at a median age of 2.5 months (interquartile range [IQR], 1.3-4.5 months). This compares with the nonoperative cohort where 64% (n = 18) would have undergone The Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery mortality category 1 procedures if surgery would have been elected. The most common diagnosis was ventricular septal defect. Postoperative median intensive care unit stay was 6.5 days (IQR, 3.7-15 days) with a total hospital length of stay of 15 days (IQR, 11-49 days). Thirty-day postoperative survival was 94%. There were 5 in-hospital deaths in the operated and 7 in the nonoperated cohort. Median follow-up was 15.4 months (IQR, 4.3-48.7 months) for the operated and 11.2 months (IQR, 1.2-48.3 months) for the nonoperated cohorts. One-year survival was 79% operated versus 51.5% nonoperated (P < .003). Nonoperative treatment had an increased risk of mortality (hazard ratio, 3.28; 95% CI, 1.46-7.4; P = .004). Conclusions: Controversy exists regarding the role of primary cardiac repair in patients with trisomy 13/18 and congenital heart disease. Cardiac repair can be performed safely with low early mortality and operated patients had higher long-term survival compared with nonoperated in our cohort.

Clinical and 2D/3D-Echo Cardiography Determinants of Mitral Valve Reoperation in Children With Congenital Mitral Valve Disease.

Background: Congenital mitral valve disease (CMVD) presents major challenges in its medical and surgical management. Objectives: The purpose of this study was to investigate the value of 3-dimensional echocardiography (3DE) and identify associations with MV reoperation in this setting. Methods: All children <18 years of age who underwent MV reconstruction for CMVD in 2002 to 2018 were included. Preoperative and postoperative 2-dimensional echocardiography (2DE) and 3DE data were collected. Competing risks and Cox regression analysis were used to identify independent associations with MV reoperation. Receiver operating characteristic and decision-tree analysis were implemented for comparison of 3DE vs 2DE. Results: A total of 206 children underwent MV reconstruction for CMVD (mitral stenosis, n = 105, mitral regurgitation [MR], n = 75; mixed disease, n = 26); 64 (31%) required MV reoperation. Variables independently associated with MV reoperation were age <1 year (HR: 2.65; 95% CI: 1.13-6.21), tethered leaflets (HR: 2.00; 95% CI: 1.05-3.82), ≥ moderate 2DE postoperative MR (HR: 4.26; 95% CI: 2.45-7.40), changes in 3D-effective orifice area (3D-EOA) and in 3D-vena contracta regurgitant area (3D-VCRA). Changes in 3D-EOA and 3D-VCRA were more strongly associated with MV reoperation than changes in mean gradients (area under the curve [AUC]: 0.847 vs AUC: 0.676, P = 0.006) and 2D-VCRA (AUC: 0.969 vs AUC: 0.720, P = 0.012), respectively. Decision-tree analysis found that a <30% increase in 3D-EOA had 80% accuracy (HR = 8.50; 95% CI: 2.9-25.1) and a <40% decrease in 3D-VCRA had 93% accuracy (HR: 22.50; 95% CI: 2.9-175) in discriminating MV reoperation for stenotic and regurgitant MV, respectively. Conclusions: Age <1 year, tethered leaflets, 2DE postoperative MR, changes in 3D-EOA and 3D-VCRA were all independently associated with MV reoperation. 3DE parameters showed a stronger association than 2DE. 3DE-based decision-tree algorithms may help prognostication and serve as a support tool for clinical decision-making.

Outcomes of Neonatal Cardiac Surgery: A European Congenital Heart Surgeons Association Study.

BACKGROUND: We evaluated outcomes of neonatal cardiac surgery at hospitals affiliated with the European Congenital Heart Surgeons Association (ECHSA). METHODS: All patients ≤30 days of life undergoing a cardiac surgical procedure during a 10-year period between January 2013 and December 2022 were selected from the ECHSA Congenital Database. Reoperations during the same hospitalization, percutaneous procedures, and noncardiac surgical procedures were excluded. We identified 12 benchmark operations. Primary outcomes were 30-day mortality and in-hospital mortality. Multivariable logistic regression analysis was performed to determine independent factors associated with higher mortality. Mortality between the first 5 years and second 5 years was also compared. RESULTS: The overall number of neonatal operations from 2013 to 2022 was 30,931, and 22,763 patients met the inclusion criteria of the study. The 4 most common procedures were arterial switch operation (3520 of 22,763 [15.5%]), aortic coarctation repair (3204 of 22,763 [14.1%]), shunt procedure (2351 of 22,763 [10.3%]), and Norwood operation (2115 of 22,763 [9.23%]). The 30-day mortality rate was as follows: overall population, 5.9% (1342 of 22,763); arterial switch, 3.13% (110 of 3520); Norwood operation, 16.0% (339 of 2115); and hybrid operation, 15.4% (94 of 609). In-hospital mortality rate was as follows: overall population, 9.1% (2074 of 22,763); arterial switch, 4.12% (145 of 3520); Norwood operation, 24.7% (523 of 2115); and hybrid operation, 30.5% (186 of 609). Multivariable analysis revealed that major factors impacting mortality were high-risk procedures (adjusted odds ratio, 2.74; 95% CI, 2.33-3.23; P < .001), and the need for extracorporeal membrane oxygenation (11.8; 95% CI, 9.9-14; P < .001). CONCLUSIONS: Neonatal cardiac surgery continues to pose a significant challenge, with notable mortality, particularly for neonates with functionally univentricular physiology. These data can serve as important benchmarks across Europe and offer insights regarding opportunities for improvement.

Predictive modeling of endocardial fibroelastosis recurrence in patients with congenital heart disease.

BACKGROUND: Endocardial fibroelastosis (EFE) is a major effector in the maldevelopment of the heart in patients with congenital heart disease. Despite successful surgical removal, EFE can redevelop, but the underlying cause of EFE recurrence remains unknown. This study aimed to identify hemodynamic predictors and genetic links to epithelial/endothelial-to-mesenchymal transition (EMT/EndMT) alterations for preoperative risk assessment. METHODS: We assessed the impact of preoperative hemodynamic parameters on EFE recurrence in a cohort of 92 patients with congenital heart disease who underwent left ventricular (LV) EFE resection between January 2010 and March 2021. Additionally, whole-exome sequencing in 18 patients was used to identify rare variants (minor allele frequency <10-5) in high-expression heart (HHE) genes related to cardiac EMT/EndMT and congenital heart disease. RESULTS: EFE recurred in 55.4% of patients, within a median of 2.2 years postsurgery. Multivariable analysis revealed specific hemodynamic parameters (mitral valve inflow and area, LV filling pressure, and aortic valve gradient and diameter) as predictors, forming a predictive model with an area under the receiver operating characteristic curve of 0.782. Furthermore, 89% of the patients exhibited damaging variants in HHE genes, with 38% linked to cardiac EMT/EndMT Gene Ontology processes and 22% associated with known congenital heart disease genes. Notably, HHE genes associated with cardiac EMT/EndMT were significantly associated with faster EFE recurrence in a multivariate analysis (hazard ratio, 3.56; 95% confidence interval, 1.24-10.17; P = .018). CONCLUSIONS: These findings established a predictive scoring system using preoperative hemodynamic parameters for EFE recurrence risk assessment. Alterations in HHE genes, particularly those linked to cardiac EMT/EndMT, exacerbate the risk of recurrence.

Odds of Attaining Orthopaedic Leadership Based on Race, Ethnicity, and Sex.

BACKGROUND: Despite widespread acceptance of the importance of diversity in leadership, systemic challenges in leadership attainment in orthopaedic surgery still exist for several groups. We hypothesize that women, underrepresented in medicine groups, and Asians have decreased odds of achieving program director and chairperson positions compared with peers. METHODS: Demographic data were collected from the Association of American Medical Colleges for faculty, program directors, and chairpersons in orthopaedic surgery. Odds ratios were calculated treating race, ethnicity, or sex as the predictor variables and attainment of a leadership position as the outcome, comparing the composition of program directors in 2020 and chairpersons in 2019 with faculty in 2019. RESULTS: Significantly decreased odds were found for women at 0.37 (0.264 to 0.51 [ P < 0.0001]) and the Other category at 0.16 (0.065 to 0.3864 [ P = 0.0001]) while significantly increased odds were found for White and Black/African American faculty at 1.32 (1.02 to 1.71 [ P = 0.0314]) and 1.95 (1.17 to 3.26 [ P = 0.011]), respectively, in holding program director positions. Significantly decreased odds of attaining chairpersonship were found for women at 0.17 (0.07 to 0.41 [ P = 0.0075]) and Asian faculty at 0.33 (0.14 to 0.75 [ P = 0.0062]) while White faculty demonstrated significantly increased odds at 2.43 (1.41 to 4.19 [ P = 0.0013]). CONCLUSIONS: Women showed markedly decreased odds of leadership attainment while Black/African American faculty had increased likelihood of becoming program directors but were not markedly more likely to become chairs. Asian faculty were less likely to become program directors and markedly less likely to become chairs. While decreased odds for women were expected based on current literature, decreased odds of Asians becoming chairs and an increased likelihood of Black/African American orthopaedic surgeons becoming program directors but not attaining the role of chairs at the same rate were novel findings, revealing concerning trends for these groups.

Transamniotic Stem Cell Therapy Modulates Uterine Natural Killer Cell Activity in the Hypoxia Model of Intrauterine Growth Restriction.

Intrauterine growth restriction (IUGR) pathophysiology is driven by abnormal uterine natural killer cell (uNK) activity leading to placental dysfunction. Transamniotic stem cell therapy (TRASCET) with mesenchymal stem cells (MSCs) can improve experimental IUGR by mechanisms not fully understood. We sought to examine TRASCET's effects in downstream products of uNKs in a model of IUGR: 15 Sprague-Dawley dams were exposed to alternating hypoxia (10.5% O2) from gestational day 15 (E15) until term (E21). Their fetuses (n = 189) were divided into four groups. One group remained untreated (n = 52), whereas three groups received volume-matched intraamniotic injections of either saline (sham, n = 44) or a suspension of amniotic fluid-derived MSCs, either in their native state (TRASCET, n = 50) or "primed" to an enhanced antiinflammatory phenotype (TRASCET-Primed, n = 43). Normal fetuses served as controls (n = 33). At term, various analyses were performed, including ELISA for surrogates of placental inflammation and uNK activity. Statistical comparisons included Bonferroni-adjusted criterion. Overall survival from hypoxia was 74% (140/189). Placental efficiency was lower in untreated and sham but normalized in both TRASCET groups (P < 0.01-0.47). Interleukin-17, a stimulator of uNKs, was elevated from normal in all groups (P < 0.01 for all). Interferon-gamma, released from activated uNKs, was elevated in all groups except sham but lower than the untreated in both TRASCET groups (P ≤ 0.01-0.06). Tumor necrosis factor-alpha, also produced by uNKs, was elevated in untreated and sham (P < 0.01 for both), but normalized by TRASCET (P = 0.05) and even lowered from normal in TRASCET-Primed (P < 0.01). Vascular endothelial growth factor, also released by uNKs, was elevated in untreated and sham but lower than normal in both TRASCET groups (P < 0.01 for all). We conclude that TRASCET with MSCs modulates the activity of placental uNKs in experimental IUGR, with distinct effects on their downstream products. This mechanistic insight may inform the development of novel strategies for the management of this disease.

Establishing Optimal Control Cohorts for Phase 1 Trials: Retrospective Analysis of Clinical and Biological Outcomes in Neonates and Infants Undergoing Two-Ventricle Repair.

Phase 1 trials are primarily conducted to evaluate the safety and feasibility of new interventions, usually without recruiting control patients. This retrospective study aims to characterize clinical and biological outcomes in historical and contemporary cases of neonates and infants undergoing two-ventricle repair to facilitate future secondary endpoint analyses for such trials. This retrospective study included neonates/infants (ages ≤ 6 months) who underwent two-ventricle repair between 2015 and 2021 using the same criteria as our phase 1 trial (n = 199). Patients were allocated into the ventricular septal defect (n = 61), the Tetralogy of Fallot (TOF, n = 88), and the transposition of the great arteries (n = 50) groups with an additional comparison between two eras (2015-2019 vs. 2020-2021). Patient characteristics and most variables assessed were different between the three diagnostic groups indicating the importance of diagnostic matching for secondary analyses. Although the era did not alter cerebral/somatic oxygenation, ventricular function, neuroimaging findings, and complication rates, we observed improvement of inotropic and/or vasoactive-inotropic scores in all groups during the more recent era. In 2020-2021, the age and the body weight at the operation were higher, and hospital stay was shorter in the TOF group, suggesting the possible impact of the pandemic. Results also indicated that matching altered characteristics such as age at operation that may limit the temporal effects and optimize secondary analyses. Using optimal contemporary cases and historical data based on this study will assist in developing a comprehensive study design for a future efficacy/effectiveness trial.

Comparative Effects on Fetal Hematopoiesis and Placental Inflammation From Mesenchymal and Hematopoietic Stem Cells as Agents of Transamniotic Stem Cell Therapy (TRASCET) in a Syngeneic Model of Intrauterine Growth Restriction.

PURPOSE: We compared transamniotic stem cell therapy (TRASCET) using either mesenchymal (MSCs) or hematopoietic (HSCs) stem cells on fetal hematopoiesis in a syngeneic model of intrauterine growth restriction (IUGR). METHODS: Lewis dams exposed to cycling hypoxia (10.5% O2) in late gestation had their fetuses (n = 83) either receiving no intervention (untreated; n = 9), or intra-amniotic injections of either HSCs (HSC; n = 34), MSCs primed to an enhanced anti-inflammatory phenotype (primed-MSC; n = 28), or saline (sham; n = 12). Normal controls (n = 18) were also studied. Complete peripheral blood counts and placental ELISA for inflammation and angiogenesis markers were performed at term. RESULTS: Overall survival from hypoxia was 41% (34/83). Red blood count (RBC), hematocrit (Hct) and hemoglobin levels (Hb) were all significantly decreased from normal in all hypoxia groups. TRASCET with primed-MSC had significantly higher RBC, Hct, and Hb levels than sham (p = 0.01-0.03, pairwise), though not than untreated (which had no surgical blood loss). The HSC group had only significantly higher Hb levels than sham (p = 0.005). TRASCET with primed-MSC had significantly lower levels of placental TNF-α than sham (p = 0.04), but not untreated. CONCLUSIONS: MCSs seem more effective than HSCs in enhancing hematopoiesis when used as donor cells for TRASCET in a syngeneic model of IUGR. LEVEL OF EVIDENCE: N/A (animal and laboratory study).

Prevalence and clinical implications of heightened plastic chemical exposure in pediatric patients undergoing cardiopulmonary bypass.

BACKGROUND: Phthalate chemicals are used to manufacture plastic medical products, including many components of cardiopulmonary bypass (CPB) circuits. We aimed to quantify iatrogenic phthalate exposure in pediatric patients undergoing cardiac surgery and examine the link between phthalate exposure and postoperative outcomes. STUDY DESIGN AND METHODS: The study included pediatric patients undergoing (n=122) unique cardiac surgeries at Children's National Hospital. For each patient, a single plasma sample was collected preoperatively and two additional samples were collected postoperatively upon return from the operating room and the morning after surgery. Concentrations of di(2-ethylhexyl) phthalate (DEHP) and its metabolites were quantified using ultra high-pressure liquid chromatography coupled to mass spectrometry. RESULTS: Patients were subdivided into three groups, according to surgical procedure: (1) cardiac surgery not requiring CPB support, (2) cardiac surgery requiring CPB with a crystalloid prime, and (3) cardiac surgery requiring CPB with red blood cells (RBCs) to prime the circuit. Phthalate metabolites were detected in all patients, and postoperative phthalate levels were highest in patients undergoing CPB with an RBC-based prime. Age-matched (<1 year) CPB patients with elevated phthalate exposure were more likely to experience postoperative complications. RBC washing was an effective strategy to reduce phthalate levels in CPB prime. DISCUSSION: Pediatric cardiac surgery patients are exposed to phthalate chemicals from plastic medical products, and the degree of exposure increases in the context of CPB with an RBC-based prime. Additional studies are warranted to measure the direct effect of phthalates on patient health outcomes and investigate mitigation strategies to reduce exposure.

Management Changes After Echocardiography Are Associated With Improved Outcomes in Critically Ill Children.

OBJECTIVES: To evaluate management changes and outcomes in critically ill children after formal echocardiography. DESIGN: Retrospective cohort study between January 1, 2011, and December 31, 2020. SETTING: Tertiary care children's hospital. PATIENTS: Patients from 1 to 18 years who had formal echocardiography within 72 hours of ICU admission and who were intubated and on vasoactive infusions at the time of the study. Patients were stratified into two cardiac function groups: 1) near-normal cardiac function and 2) depressed cardiac function. METHODS: Clinical variables were abstracted from the electronic medical record and placed in time sequence relative to echocardiography. Vasoactive and fluid management strategies in place before echocardiography were associated with markers of tissue perfusion and volume overload. Management changes after echocardiography were characterized and associated with outcomes. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Among patients eventually found to have depressed cardiac function, the use of vasoconstrictors was associated with worse lactate clearance and oxygen extraction ratio. Use of vasoconstrictors in this cohort was also associated with a more liberal fluid management strategy, evidence of increased lung water, and a worse Sp o2 /F io2 . An echocardiogram demonstrated depressed cardiac function was likely to be followed by management changes that favored inotropes and more conservative fluid administration. Patients with depressed cardiac function who were switched to inotropes were more likely to be extubated and to wean off vasoactive support compared with those patients who remained on vasoconstrictors. CONCLUSIONS: Among patients with depressed cardiac function, alterations in management strategy after echocardiography are associated with shortened duration of intensive care interventions.

Lower Extremity Growth according to AI Automated Femorotibial Length Measurement on Slot-Scanning Radiographs in Pediatric Patients.

Background Commonly used pediatric lower extremity growth standards are based on small, dated data sets. Artificial intelligence (AI) enables creation of updated growth standards. Purpose To train an AI model using standing slot-scanning radiographs in a racially diverse data set of pediatric patients to measure lower extremity length and to compare expected growth curves derived using AI measurements to those of the conventional Anderson-Green method. Materials and Methods This retrospective study included pediatric patients aged 0-21 years who underwent at least two slot-scanning radiographs in routine clinical care between August 2015 and February 2022. A Mask Region-based Convolutional Neural Network was trained to segment the femur and tibia on radiographs and measure total leg, femoral, and tibial length; accuracy was assessed with mean absolute error. AI measurements were used to create quantile polynomial regression femoral and tibial growth curves, which were compared with the growth curves of the Anderson-Green method for coverage based on the central 90% of the estimated growth distribution. Results In total, 1874 examinations in 523 patients (mean age, 12.7 years ± 2.8 [SD]; 349 female patients) were included; 40% of patients self-identified as White and not Hispanic or Latino, and the remaining 60% self-identified as belonging to a different racial or ethnic group. The AI measurement training, validation, and internal test sets included 114, 25, and 64 examinations, respectively. The mean absolute errors of AI measurements of the femur, tibia, and lower extremity in the test data set were 0.25, 0.27, and 0.33 cm, respectively. All 1874 examinations were used to generate growth curves. AI growth curves more accurately represented lower extremity growth in an external test set (n = 154 examinations) than the Anderson-Green method (90% coverage probability: 86.7% [95% CI: 82.9, 90.5] for AI model vs 73.4% [95% CI: 68.4, 78.3] for Anderson-Green method; χ2 test, P < .001). Conclusion Lower extremity growth curves derived from AI measurements on standing slot-scanning radiographs from a diverse pediatric data set enabled more accurate prediction of pediatric growth. © RSNA, 2024 Supplemental material is available for this article.

How Did Black and Hispanic Orthopaedic Applicants and Residents Compare to General Surgery Between 2015 and 2022?

BACKGROUND: Despite the heavy demand for and knowledge of the benefits of diversity, there is a persistent lack of racial, ethnic, and gender diversity in orthopaedic surgery. Since the implementation of diversity initiatives, data have shown that general surgery has been one of the top competitive surgical fields and has demonstrated growth in racial, ethnic, and gender diversity, making general surgery a good point of reference and comparison when analyzing racial and ethnic growth in orthopaedic surgery. QUESTIONS/PURPOSES: (1) What were the growth rates for Black and Hispanic orthopaedic residency applicants and residents between 2015 and 2022? (2) How did the growth rates of Black and Hispanic individuals in orthopaedic surgery compare with those of general surgery? (3) How did applicant recruitment and resident acceptance differ between Black and Hispanic people in orthopaedic surgery? METHODS: Applicant data were obtained from historical specialty-specific data from the Association of American Medical Colleges Electronic Residency Application Service Statistics database between 2018 and 2022, and resident data were obtained from the Accreditation Council of Graduate Medical Education Data Resource Book between 2015 and 2021. Between 2018 and 2022, the number of residency applicants totaled 216,677, with 17,912 Black residency applicants and 20,413 Hispanic residency applicants. Between 2015 and 2021, the number of active residents totaled 977,877, with 48,600 Black residents and 62,605 Hispanic residents. Because the applicant and resident data do not overlap throughout all years of observation, a sensitivity analysis of overlapping years (between 2018 and 2021) was conducted to ensure observed trends were consistent and valid throughout the study. All datasets obtained were used to establish the different racial and ethnic proportions of Black and Hispanic residency applicants and residents in four nonsurgical primary care specialties and four surgical subspecialties. A reference slope was created using data from the Association of American Medical Colleges and Accreditation Council of Graduate Medical Education to represent the growth rate for total residency applicants and residents, independently, across all residency specialties reported in each database. This slope was used for comparison among the resident and applicant growth rates for all eight selected specialties. Datapoints were placed into a scatterplot with regression lines, using slope equations to depict rate of growth and R 2 values to depict linear fit. Applicant growth corresponded to applicant recruitment and resident growth corresponded to resident acceptance. Chi-square tests were used to compare residents and residency applicants for the Black and Hispanic populations, separately. Two-way analysis of variance with a time-by-specialty interaction term (F-test) was conducted to determine differences between growth slopes. RESULTS: There was no difference in the growth rate of Black orthopaedic surgery applicants between 2018 and 2022, and there was no difference in the growth rate of Hispanic orthopaedic surgery applicants (R 2 = 0.43; p = 0.23 and R 2 = 0.63; p = 0.11, respectively). However, there was a very slight increase in the growth rate of Black orthopaedic surgery residents between 2015 and 2021, and a very slight increase in the growth rate of Hispanic orthopaedic surgery residents (R 2 = 0.73; p = 0.02 and R 2 = 0.79; p = 0.01, respectively). There were no differences in orthopaedic and general surgery rates of growth for Black applicants between 2018 and 2022 (0.004 applicants/year versus -0.001 applicants/year; p = 0.22), and no differences were found in orthopaedic and general surgery rates of growth for Black residents between 2015 and 2021 (0.003 residents/year versus 0.002 residents/year; p = 0.59). Likewise, Hispanic orthopaedic applicant growth rates did not differ between 2018 and 2022 from the rates of general surgery (0.004 applicants/year versus 0.005 applicants/year; p = 0.68), and there were no differences in orthopaedic and general surgery rates of growth for Hispanic residents (0.007 residents/year versus 0.01 residents/year; p = 0.35). Furthermore, growth rate comparisons between Black orthopaedic applicants and residents between 2018 and 2021 showed applicant growth was larger than resident growth, illustrating that the recruitment of Black applicants increased slightly more rapidly than resident acceptance. Growth rate comparisons between Hispanic applicants and residents showed a larger rate of resident growth, illustrating Hispanic resident acceptance increased slightly faster than applicant recruitment during that time. CONCLUSION: We found low acceptance of Black residents compared with the higher recruitment of Black applicants, as well as overall low proportions of Black and Hispanic applicants and residents. Future studies might explore the factors contributing to the higher acceptances of Hispanic orthopaedic residents than Black orthopaedic residents. CLINICAL RELEVANCE: We recommend that more emphasis should be placed on increasing Black and Hispanic representation at the department level to ensure cultural considerations remain at the forefront of applicant recruitment. Internal or external reviews of residency selection processes should be considered, and more immersive, longitudinal orthopaedic surgery clerkships and research mentorship experiences should be targeted toward Black and Hispanic students. Holistic reviews of applications and selection processes should be implemented to produce an increased racially and ethnically diverse applicant pool and a diverse residency work force, and implicit bias training should be implemented to address potential biases and diversity barriers that are present in residency programs and leadership.

Locally Directed Recombinant Adeno- Associated Virus-Mediated IGF-1 Gene Therapy Enhances Osteochondral Repair and Counteracts Early Osteoarthritis In Vivo.

BACKGROUND: Restoration of osteochondral defects is critical, because osteoarthritis (OA) can arise. HYPOTHESIS: Overexpression of insulin-like growth factor 1 (IGF-1) via recombinant adeno-associated viral (rAAV) vectors (rAAV-IGF-1) would improve osteochondral repair and reduce parameters of early perifocal OA in sheep after 6 months in vivo. STUDY DESIGN: Controlled laboratory study. METHODS: Osteochondral defects were created in the femoral trochlea of adult sheep and treated with rAAV-IGF-1 or rAAV-lacZ (control) (24 defects in 6 knees per group). After 6 months in vivo, osteochondral repair and perifocal OA were assessed by well-established macroscopic, histological, and immunohistochemical scoring systems as well as biochemical and micro-computed tomography evaluations. RESULTS: Application of rAAV-IGF-1 led to prolonged (6 months) IGF-1 overexpression without adverse effects, maintaining a significantly superior overall cartilage repair, together with significantly improved defect filling, extracellular matrix staining, cellular morphology, and surface architecture compared with rAAV-lacZ. Expression of type II collagen significantly increased and that of type I collagen significantly decreased. Subchondral bone repair and tidemark formation were significantly improved, and subchondral bone plate thickness and subarticular spongiosa mineral density returned to normal. The OA parameters of perifocal structure, cell cloning, and matrix staining were significantly better preserved upon rAAV-IGF-1 compared with rAAV-lacZ. Novel mechanistic associations between parameters of osteochondral repair and OA were identified. CONCLUSION: Local rAAV-mediated IGF-1 overexpression enhanced osteochondral repair and ameliorated parameters of perifocal early OA. CLINICAL RELEVANCE: IGF-1 gene therapy may be beneficial in repair of focal osteochondral defects and prevention of perifocal OA.