Faculty Bibliography

BACKGROUND:Ultrasound-guided (US) transversus abdominis plane (TAP) block is commonly utilized as part of a multi-modal approach for postoperative pain management. This study seeks to determine whether laparoscopic-guided TAP blocks are as effective as US-guided TAP blocks among pediatric patients. METHOD/METHODS:In this prospective, randomized controlled trial, pediatric patients undergoing laparoscopic procedures were randomly assigned to one of two treatment arms: US-guided TAP block (US-arm) or laparoscopic-guided TAP block (LAP-arm). Primary outcome was PACU pain scores. Secondary outcomes included PACU opioid consumption, block completion time and block accuracy. RESULTS:Twenty-five patients were enrolled in each arm. In the LAP-arm, 59% of blocks were in the transversus abdominis plane compared to 74% of TAP blocks in the US-arm (p = 0.18). Blocks were completed faster in the LAP-arm (2.1 ± 1.9 vs. 7.9 ± 3.4 min, p<0.001). The average highest PACU pain score was 3.4 ± 3.1 for the LAP-arm and 4.3 ± 3.8 for the US-arm (p = 0.37). Overall PACU pain scores and opioid consumption were similar between the groups (1.2 ± 1.3 vs. 1.6 ± 1.6, p = 0.24; 2.2 ± 5.8 vs. 0.9 ± 1.4MME, p = 0.26). CONCLUSION/CONCLUSIONS:Laparoscopic TAP blocks have equivalent efficacy in post-operative pain scores, narcotic use, and tissue plane accuracy as compared to US-guided TAP blocks. They are also completed faster and may result in less operating room and general anesthetic time for the pediatric patient.

BACKGROUND/PURPOSE/OBJECTIVE:Intraluminal springs have recently been shown to lengthen segments of intestine in a process known as distraction enterogenesis. We hypothesized that biocompatible springs could be used to lengthen defunctionalized murine small intestine and would lead to identifiable intestinal adaptations at the molecular level. METHODS:Age and weight matched C57BL/6 mice underwent surgical insertion of nitinol spring-loaded capsules into a Roux limb of jejunum. Segment lengths were measured at initial spring placement and at euthanasia after 14 and 21 days. Histology and gene expression of the Roux limb were evaluated at scarification and compared to untreated control segments. RESULTS:Intestinal segments loaded with compressed springs lengthened an average of 240%, which was significantly longer than control segments loaded with either empty capsules or uncompressed springs. Muscularis thickening was greater in spring-treated mice compared to controls without springs. Crypt depth and Lgr5+ expression was greater in mice that received compressed spring treatments when compared to control groups. CONCLUSIONS:Insertion of a compressed nitinol spring into a Roux limb results in significant intestinal lengthening, smooth muscle thickening, and Lgr5+ expression in a mouse model. The ability to increase small bowel length in a defunctionalized murine model may be used to understand the mechanism of distraction enterogenesis.

BACKGROUND:Short gut syndrome, a condition characterized by inadequate absorption of nutrients owing to decreased bowel length, has minimal avenues for treatment. We have proposed spring-mediated distraction enterogenesis to lengthen bowel in porcine jejunum as a treatment for short gut. We aim to evaluate the extent of mesenteric neovascularization in segments of lengthened bowel via spring-mediated enterogenesis. METHODS:Female juvenile Yucatan pigs underwent laparotomy and insertion of gelatin-encapsulated compressed nitinol springs, held in place with plication sutures, into the jejunum. At surgery and sacrifice, macroscopic mesenteric blood vessels were counted between the plication sites. Histologic samples of the mesentery were obtained to evaluate microscopic vasculature. RESULTS:A statistically significant increase in macroscopic mesenteric blood vessels was seen after intestinal lengthening (before: 1.9 ± 0.7 vessels, after: 4.7 ± 1.2 vessels, p = 0.001). A statistical significance is also seen in the density of arterioles (control: 3.0 ± 3.0 vessels/mm, spring: 7.0 ± 9.0 vessels/mm, p = 0.01) and venules (control: 4.0 ± 3.0 vessels/mm, spring: 8.0 ± 8.0 vessels/mm, p = 0.003). CONCLUSION/CONCLUSIONS:Intestinal segments lengthened by intraluminal springs demonstrated total greater number of macroscopic vessels and microscopic blood vessels per length of mesentery as compared to control. This suggests local changes within the mesentery to recruit blood supply to growing intestine. LEVEL OF EVIDENCE/METHODS:N/A TYPE OF STUDY: Treatment study.

Pediatric firearm-related injuries pose a significant public health problem in the United States, yet the associated financial burden has not been well described. This is the first study examining national data on the cost of initial hospitalization for pediatric firearm-related injuries. In this retrospective review, the Healthcare Cost and Utilization Project Kids' Inpatient Database from the years 2003, 2006, 2009, and 2012 was used to identify all patients 18 years of age and under who were admitted with firearm-related injuries. We compared demographic and discharge-level data including injury severity score, hospital length of stay, income quartile, injury intent, and inflation-adjusted hospital costs across age groups (0-5, 6-9, 10-15, 16-18 years). There were approximately 4,753 pediatric firearm-related admissions each year, with a median hospitalization cost of $12,984 per patient. Annual initial hospitalization costs for pediatric firearm injuries were approximately $109 million during the study period. Pediatric firearm-related injuries predominately occured among older teenagers (74%, 16-18 years), males (89%), black individuals (55%), and those from the lowest income quartile (53%). We found significant cost variation based on patient race, income quartile, injury severity score, intent, hospital length of stay, disposition, and hospital region. Inflation-adjusted hospitalization costs have increased significantly over the study period (p < 0.001). Pediatric firearm-related injuries are a large financial burden to the United States healthcare system. There are significant variations in cost based on predictable factors like hospital length of stay and injury severity score; however, there are also substantial discrepancies based on hospital region, patient race, and income quartile that require further investigation.

PURPOSE/OBJECTIVE:One in 5000 newborns is diagnosed with Hirschsprung disease each year in the United States. The potential of employing neural crest stem cells to restore the enteric nervous system has been investigated. Skin-derived precursor cells (SKPs) are multipotent progenitor cells that can differentiate into neurons and gliocytes in vitro and generate enteric ganglion-like structures in rodents. Here we examined the behavior of human SKPs (hSKPs) after their transplantation into a large animal model of colonic aganglionosis. METHODS:Juvenile minipigs underwent a chemical denervation of the colon to establish an aganglionosis model. The hSKPs were generated from human foreskin and were cultured in neuroglial-selective medium. Cells were labeled with a fluorescent dye and were injected into the porcine aganglionic colon. After one week, transplanted hSKPs were assessed by immunofluorescence for markers of multipotency and neuroglial differentiation. RESULTS:In culture, hSKPs expressed nestin and S100b indicative of neuroglial precursors. After xenografting in pigs, hSKPs were identified in the myenteric and submucosal plexuses of the colons. The hSKPs expressed nestin and early neuroglial differentiation markers. CONCLUSIONS:Human SKPs transplanted into aganglionic colon demonstrated immunophenotypes of neuroglial progenitors, suggesting their potential use for Hirschsprung disease.

BACKGROUND:Per-oral endoscopic myotomy (POEM), a modern treatment for achalasia, has only recently emerged as an option for pediatric patients. Here we describe and characterize the success of POEM in children with achalasia. METHODS:A single-institution prospective cohort study was performed of patients <18 years old who underwent POEM from 2014 to 2019. Main outcomes were success at one year (Eckardt ≤3), procedure duration, complications, reintervention. RESULTS:The median age of patients (n = 21) was 13 years (range 2-17). Median procedure duration was 92 min (range 52-259) with case duration plateau of 87.4 min and learning rate of 15.5 cases. Intraoperative complications included capnoperitoneum requiring needle decompression and mucosotomy requiring additional clips. One patient experienced chest pain with small capnoperitoneum seen on chest radiography, and three patients had extraluminal carbon dioxide found incidentally on routine radiography. All were managed with observation. Pre- versus 1-month postprocedure Eckardt scores were significantly improved (7 ± 2 versus 1 ± 2, p < 0.0001, and median ± SD) with 100% symptomatic relief at one year. To achieve this, 13 patients required further dilation(s), one required laparoscopic Heller myotomy, and two required repeat POEM. CONCLUSIONS:POEM is a viable and safe treatment for pediatric patients with achalasia. We demonstrate improvement in symptoms and procedure proficiency with minimal intra- and postoperative complications. TYPE OF STUDY/METHODS:Prospective cohort study. LEVEL OF EVIDENCE/METHODS:Level II.

BACKGROUND:Neuroblastoma is the most common pediatric extracranial solid malignancy with limited effective treatment. We have shown that sustained-release, single drugs delivered locally through a silk-based biomaterial are effective in decreasing orthotopic neuroblastoma xenograft growth. We further optimized this approach and hypothesized that increasing doses of local chemotherapy or delivering 2 chemotherapeutic agents simultaneously inhibit additional tumor growth. METHODS:MYCN-amplified and non-MYCN-amplified neuroblastoma cells were treated with combinations of cisplatin, vincristine, doxorubicin, and etoposide to determine cytotoxicity and synergy. Drug-loaded silk material was created, and the amounts of drug released from the material over time were recorded. Murine orthotopic neuroblastoma xenografts were generated; tumors were implanted with single- or dual-agent chemotherapy-loaded silk. Ultrasound was used to monitor tumor growth, and tumor histology was evaluated. RESULTS:In vitro, vincristine/cisplatin combination was synergistic and significantly decreased cell viability relative to other combinations. Both drugs loaded into silk could be released effectively for over 2 weeks. Locally implanted vincristine/cisplatin silk induced increased tumor growth suppression compared with either agent alone in MYCN-amplified tumors (P < .05). The dose-dependent effect seen in MYCN-amplified tumors treated with combination therapy diminished at higher doses in non-MYCN-amplified tumors, with little benefit with doses >50 μg to 500 μg for vincristine-cisplatin, respectively. Tumor histology demonstrated tumor cell necrosis adjacent to drug-loaded silk material and presence of large cell neuroblastoma. CONCLUSION:Local delivery of sustained release chemotherapy can suppress tumor growth especially at high doses or with 2 synergistic drugs. Locally delivered dual therapy is a promising approach for future clinical testing.

Immunotherapy targeting GD2 is a primary treatment for patients with high-risk neuroblastoma. Dinutuximab is a monoclonal antibody with great clinical promise but is limited by side effects such as severe pain. Local delivery has emerged as a potential mechanism to deliver higher doses of therapeutics into the tumor bed, while limiting systemic toxicity. We aim to deliver dinutuximab locally in a lyophilized silk fibroin foam for the treatment of an orthotopic neuroblastoma mouse model. Dinutuximab-loaded silk fibroin foams were fabricated through lyophilization. In vitro release profile and bioactivity of the release through complement-dependent cytotoxicity were characterized. MYCN-amplified neuroblastoma cells (KELLY) were injected into the left gland of mice to generate an orthotopic neuroblastoma model. Once the tumor volume reached 100 mm³ , dinutuximab-, human IgG-, or buffer-loaded foams were implanted into the tumor and growth was monitored using high-resolution ultrasound. Post-resection histology was performed on tumors. Dinutuximab-loaded silk fibroin foams exhibited a burst release, with slow release thereafter in vitro with maintenance of bioactivity. The dinutuximab-loaded foam significantly inhibited xenograft tumor growth compared to IgG- and buffer-loaded foams. Histological analysis revealed the presence of dinutuximab within the tumor and neutrophils and macrophages infiltrating into dinutuximab-loaded silk foam. Tumors treated with local dinutuximab had decreased MYCN expression on histology compared to control or IgG-treated tumors. Silk fibroin foams offer a mechanism for local release of dinutuximab within the neuroblastoma tumor. This local delivery achieved a significant decrease in tumor growth rate in a mouse orthotopic tumor model.

Neuroblastoma is a deadly pediatric solid tumor with infrequent recurrent somatic mutations. Particularly, the pathophysiology of tumors without MYCN amplification remains poorly defined. Utilizing an unbiased approach, we performed gene set enrichment analysis of RNA-sequencing data from 498 patients with neuroblastoma and revealed a differentially overexpressed gene signature in MYCN nonamplified neuroblastomas with telomerase reverse transcriptase (TERT) gene overexpression and coordinated activation of oncogenic signaling pathways, including E2Fs, Wnt, Myc, and the DNA repair pathway. Promoter rearrangement of the TERT gene juxtaposes the coding sequence to strong enhancer elements, leading to TERT overexpression and poor prognosis in neuroblastoma, but TERT-associated oncogenic signaling remains unclear. ChIP-seq analysis of the human CLB-GA neuroblastoma cells harboring TERT rearrangement uncovered genome-wide chromatin co-occupancy of Brd4 and H3K27Ac and robust enrichment of H3K36me3 in TERT and multiple TERT-associated genes. Brd4 and cyclin-dependent kinases (CDK) had critical regulatory roles in the expression and chromatin activation of TERT and multiple TERT-associated genes. Epigenetically targeting Brd4 or CDKs with their respective inhibitors suppressed the expression of TERT and multiple TERT-associated genes in neuroblastoma with TERT overexpression or MYCN amplification. ChIP-seq and ChIP-qPCR provided evidence that the CDK inhibitor directly inhibited Brd4 recruitment to activate chromatin globally. Therefore, inhibiting Brd4 and CDK concurrently with AZD5153 and dinaciclib would be most effective in tumor growth suppression, which we demonstrated in neuroblastoma cell lines, primary human cells, and xenografts. In summary, we describe a unique mechanism in neuroblastoma with TERT overexpression and an epigenetically targeted novel therapeutic strategy. SIGNIFICANCE: Epigenetically cotargeting Brd4 and Cdks suppresses human neuroblastoma with TERT overexpression by inhibiting the TERT-associated gene expression networks.

During recent years, distraction enterogenesis has been extensively studied as a treatment for short bowel syndrome, which is the most common cause of intestinal failure. Although different strategies such as parenteral nutrition and surgical lengthening have been used to manage the difficulties that patients with SBS deal with, these treatments are associated with high complication rates. Distraction enterogenesis uses mechanical force to increase the length and stimulate growth of the small intestine. In this study we combine in vivo experiments with computational modeling to explore the biomechanics of spring dependent distraction enterogenesis. We hypothesize that the self-expanding spring provides mechanical force for elastic tissue lengthening and triggers cellular proliferation. The additional growth of the intestine suggests signaling between mechanical stress and tissue response. We developed a computational modeling platform to test the correlation of applied mechanical force and tissue growth. We further validated our computational models with experimental measurements using spring-mediated distraction enterogenesis in a porcine model. This modeling platform can incorporate patient biometrics to estimate an individual's tissue response to spring mediated distraction enterogenesis.