Spleen Organoid Units Generate Functional Human and Mouse Tissue-Engineered Spleen in a Murine Model.

Introduction: Splenectomy is common after trauma or hematologic disease, and alters immune protection against pathogens, which may lead to fulminant infection with high mortality. Yet the spleen has demonstrable regenerative capacity and cells might be recovered and reimplanted at the time of injury or excision to avoid these risks. Methods: Tissue-engineered spleen (TESp) was generated from ActinGFP mice (mTESp) or human donor spleen (hTESp) through implantation of spleen organoid units (spleen OU), in NOD/SCID mice with concurrent splenectomy, on a biodegradable scaffold. Explants were evaluated and blood smears were obtained to investigate the presence of target cells or Howell-Jolly bodies, which are erythrocyte sequelae of asplenia. Results: TESp was generated from mouse (mTESp) and human (hTESp) donor cells with essential splenic components: red and white pulp with trabeculae. mTESp and hTESp demonstrated green fluorescent protein- or lamin-positive costaining with proliferating cell nuclear antigen, CD4, and CD11c, identifying proliferative donor cells and key immune components of the spleen of donor origin. Animals with hTESp and mTESP combined with splenectomy had significantly fewer Howell-Jolly bodies on blood smears than controls. Conclusion: TESp from mouse and human donor cells can be generated by 4 weeks and contains donor immune cells identified by CD4 and CD11c. TESp reduces postsplenectomy erythrocyte inclusions, indicating possible function. Impact Statement Overwhelming postsplenectomy infection is rare but highly mortal. Tissue-engineered spleen (TESp) was generated from murine (mTESp) and human (hTESp) donors and appeared histologically similar to native spleen. Both mTESp and hTESp demonstrated proliferative cells of donor spleen origin. Importantly, functional cells were demonstrated on imaging with a corresponding reduction in the number of erythrocyte inclusions in blood smears that are typically identified in patients with asplenia and indicate a lack of clearance by functional spleen tissue. Taken together, these findings indicate that this approach might be clinically relevant as a future human therapy.

Screening for blunt cerebrovascular injuries in pediatric trauma patients.

BACKGROUND: Adult imaging for blunt cerebrovascular injuries (BCVI) is based on the Denver and Memphis screening criteria where CT angiogram (CTA) is performed for any one of the criteria being positive. These guidelines have been extrapolated to the pediatric population. We hypothesize that the current adult criteria applied to pediatrics lead to unnecessary CTA in pediatric trauma patients. STUDY DESIGN: At our center, a 9-year retrospective study revealed that strict adherence to the Denver and Memphis criteria would have resulted in 332 unnecessary CTAs out of 2795 trauma patients with only 0.3% positive for BCVI. We also conducted a retrospective chart review of 776,355 pediatric trauma patients in the National Trauma Data Bank (NTDB) from 2007 to 2014. Data collection included children between ages 0 and 18, ICD-9 search for blunt cerebrovascular injury, and ICD-9 codes that applied to both Denver and Memphis criteria. RESULTS: Of 776,355 pediatric trauma activations, 81,294 pediatric patients in the NTDB fit the Denver/Memphis criteria for screening CTA neck or angiography based on ICD-9 codes, while only 2136 patients suffered BCVI. Strict utilization of the Denver/Memphis criteria would have led to a negative CTA in 79,158 (97.4%) patients. Multivariate regression analysis indicates that patients with skull base fracture, cervical spine fractures, cervical spine fracture with cervical cord injury, traumatic jugular venous injury, and cranial nerve injury should be considered part of the screening criteria for BCVI. CONCLUSION: Our study suggests the Denver and Memphis criteria are inadequate screening criteria for CTA looking for BCVI in the pediatric blunt trauma population. New criteria are needed to adequately indicate the need for CT angiography in the pediatric trauma population. LEVEL OF EVIDENCE: IV.

Non-Operative Management is More Cost-Effective than Immediate Operation in Perforated Appendicitis Patients with Seven or More Days of Symptoms.

BACKGROUND: Management of perforated appendicitis in children remains controversial. Nonoperative (NO) and immediate operative (IO) strategies are used with varying outcomes. We hypothesized that IO intervention for patients with perforated appendicitis would be more cost-effective than NO management. METHODS: A retrospective chart review of all patients with appendicitis from 2012 to 2015 was performed. Patients with perforated appendicitis were defined by evidence of perforation on imaging. We excluded patients who presented with sepsis, organ failure, and ventriculoperitoneal shunts. NO management was determined by surgeon preference. Univariate and multivariate analyses were performed. RESULTS: IO was performed on 145 patients with perforated appendicitis, whereas 83 were treated with NO management. Compared to IO patients, NO patients incurred higher overall costs, greater length of stay, more readmissions, complications, peripherally inserted central venous catheter lines, interventional radiology drains, and unplanned clinic and emergency department visits (P < 0.0001 for all). Multivariate analysis adjusting for age, days of symptoms, admission C-reactive protein and white blood cell count revealed that NO management was independently associated with increased costs (OR 1.35, 1.12-1.62, 95% CI). Cost curves demonstrated that total cost for IO surpasses that of NO management when patients present with greater than 6.3 d of symptoms (P = 0.01). CONCLUSIONS: Our data suggest that IO is more cost-effective than NO management for patients with perforated appendicitis who present with less than 6.3 d of symptoms, after which point, NO management is more cost-effective. LEVEL OF EVIDENCE: IV.

Wnt signaling inhibition by monensin results in a period of Hippo pathway activation during intestinal adaptation in zebrafish.

Intestinal adaptation (IA) is a critical response to increase epithelial surface area after intestinal loss. Short bowel syndrome (SBS) may follow massive intestinal resection in human patients, particularly without adequate IA. We previously validated a model in zebrafish (ZF) that recapitulates key SBS pathophysiological features. Previous RNA sequencing in this model identified upregulation of genes in the Wnt and Hippo pathways. We therefore sought to identify the timeline of increasing cell proliferation and considered the signaling that might underpin the epithelial remodeling of IA in SBS. SBS was created in a ZF model as previously reported and compared with sham fish with and without exposure to monensin, an ionophore known to inhibit canonical Wnt signaling. Rescue of the monensin effects was attempted with a glycogen synthase kinase 3 inhibitor that activates wnt signaling, CHIR-99021. A timeline was constructed to identify peak cellular proliferation, and the Wnt and Hippo pathways were evaluated. Peak stem cell proliferation and morphological changes of adaptation were identified at 7 days. Wnt inhibition diminished IA at 2 wk and resulted in activation of genes of the Wnt/ß-catenin and Yes-associated protein (YAP)/Hippo pathway. Increased cytoplasmic YAP was observed in monensin-treated SBS fish. Genes of the WASP-interacting protein (WIP) pathway were elevated during Wnt blockade. In conclusion, cellular proliferation and morphological changes accompany SBS even in attempted Wnt blockade. Wnt/ß-catenin, YAP/Hippo pathway, and WIP pathway genes increase during early Wnt blockade. Further understanding of the effects of Wnt and YAP pathway signaling in proliferating stem cells might enrich our knowledge of targets to assist IA. NEW & NOTEWORTHY Intestinal adaptation is a critical response to increase epithelial surface area after large intestinal losses. Inhibition of Wnt/ß-catenin signaling impairs intestinal adaptation in a zebrafish model of short bowel syndrome. There is a subsequent upregulation in genes of the Yes-associated protein/Hippo and WIP pathway. These may be targets for future human therapies, as patients are salvaged by the compensation of increased intestinal epithelial surface area through successful intestinal adaptation.

Is less more? Laparoscopic versus open Ladd's procedure in children with malrotation.

BACKGROUND: With the advent of minimally invasive techniques, laparoscopic Ladd's procedure is increasingly used to treat children with malrotation, yet evidence regarding its safety and efficacy is lacking. We hypothesize that operative and postoperative outcomes with the open technique are superior to the laparoscopic Ladd's procedure. METHODS: We conducted a 5-y retrospective chart review of all patients who underwent Ladd's procedure at our institution from 2010-2015. Exclusion of patients included those with concomitant conditions, such as poor gut perfusion, significant reflux, tracheoesophageal fistula, failure to thrive requiring concomitant gastrostomy, and biliary atresia. Kruskal-Wallis and Mann-Whitney tests were used where appropriate. RESULTS: Between 2010 and 2015, of 130 patients who underwent Ladd's procedure, 77 met inclusion criteria. Sixty-two patients underwent initial open surgery, 15 patients underwent laparoscopy, seven of which were converted to open. Patients undergoing open surgery were younger compared to the laparoscopic groups. Thirty-three of the 77 malrotation patients (43%) presented with volvulus, 27 underwent open surgery, four had laparoscopic converted to open procedures, and two patients underwent laparoscopic Ladd's without incident. Laparoscopy resulted in increased operative time and clinic visits. Patients undergoing laparoscopic to open surgery had longer operative times, time to resume diet, and length of hospital stay. No difference was noted in complications among the groups. CONCLUSIONS: Although minimally invasive approaches are becoming increasingly used, no evidence supports laparoscopic superiority over open Ladd's procedure. We found that open surgery was associated with shorter operating times and fewer clinic visits. Furthermore, laparotomy remains the favored procedure for patients presenting with volvulus.

Evolving understanding of neonatal necrotizing enterocolitis.

PURPOSE OF REVIEW: Necrotizing enterocolitis (NEC) is a devastating disease that predominately affects premature neonates. The pathogenesis of NEC is multifactorial and poorly understood. Risk factors include low birth weight, formula-feeding, hypoxic/ischemic insults, and microbial dysbiosis. This review focuses on our current understanding of the diagnosis, management, and pathogenesis of NEC. RECENT FINDINGS: Recent findings identify specific mucosal cell types as potential therapeutic targets in NEC. Despite a broadly accepted view that bacterial colonization plays a key role in NEC, characteristics of bacterial populations associated with this disease remain elusive. The use of probiotics such as lactobacilli and bifidobacteria has been studied in numerous trials, but there is a lack of consensus regarding specific strains and dosing. Although growth factors found in breast milk such as epidermal growth factor and heparin-binding epidermal growth factor may be useful in disease prevention, developing new therapeutic interventions in NEC critically depends on better understanding of its pathogenesis. SUMMARY: NEC is a leading cause of morbidity and mortality in premature neonates. Recent data confirm that growth factors and certain bacteria may offer protection against NEC. Further studies are needed to better understand the complex pathogenesis of NEC.

Hospital admission unnecessary for successful uncomplicated radiographic reduction of pediatric intussusception.

PURPOSE: After radiologic reduction, patients with ileocolic intussusception are often admitted. We hypothesize that discharge of stable patients after 4 h of emergency department (ED) observation does not result in an increase of adverse outcomes. METHODS: We retrospectively reviewed pediatric patients with ileocolic intussusception between 2011 and 2016, managed with either 24-h inpatient or 4-h ED observation. Outcomes included length of stay, adverse outcomes, and total hospital charges. RESULTS: Fifty-one patients were managed with ED observation and 79 with inpatient observation. Recurrence rates, time to recurrence, and adverse outcomes were similar in both protocols. Total recurrence rates for ED observation was 15% versus 14% for inpatient observation. ED observation reduced time in the hospital by 26.8 h (4.9 versus 31.7 h). CONCLUSION: Discharging patients following uncomplicated hydrostatic reduction of ileocolic intussusception after a 4-h observation period does not result in an increase in adverse outcomes.