Mubina A. Isani

Limiting chest computed tomography in the evaluation of pediatric thoracic trauma.

BACKGROUND Computed tomography (CT) of the chest (chest CT) is overused in blunt pediatric thoracic trauma. Chest CT adds to the diagnosis of thoracic injury but rarely changes patient management. We sought to identify a subset of blunt pediatric trauma patients who would benefit from a screening chest CT based on their admission chest x-ray (CXR) findings. We hypothesize that limiting chest CT to patients with an abnormal mediastinal silhouette identifies intrathoracic vascular injuries not otherwise seen on CXR. METHODS All blunt trauma activations that underwent an admission CXR at our Level 1 pediatric trauma center from 2005 to 2013 were retrospectively reviewed. Patients who had a chest CT were evaluated for added diagnoses and change in management after CT. RESULTS An admission CXR was performed in 1,035 patients. One hundred thirty-nine patients had a CT, and the diagnosis of intra-thoracic injury was added in 42% of patients. Chest CT significantly increased the diagnosis of contusion or atelectasis (30.3% vs 60.4%; p < 0.05), pneumothorax (7.2% vs 18.7%; p < 0.05), and other fractures (4.3% vs 10.8%; p < 0.05) on CXR compared to chest CT. Chest CT changed the management of only 4 patients (2.9%). Two patients underwent further radiologic evaluation that was negative for injury, one had a chest tube placed for an occult pneumothorax before exploratory laparotomy, and one patient had a thoracotomy for repair of aortic injury. Chest CT for select patients with an abnormal mediastinal silhouette on CXR would have decreased CT scans by 80% yet still identified patients with an intrathoracic vascular injury. CONCLUSIONS The use of chest CT should be limited to the identification of intrathoracic vascular injuries in the setting of an abnormal mediastinal silhouette on CXR. LEVEL OF EVIDENCE Therapeutic study, level IV; diagnostic study, level III.

Prolonged Absence of Mechanoluminal Stimulation in Human Intestine Alters the Transcriptome and Intestinal Stem Cell Niche

Background & Aims For patients with short-bowel syndrome, intestinal adaptation is required to achieve enteral independence. Although adaptation has been studied extensively in animal models, little is known about this process in human intestine. We hypothesized that analysis of matched specimens with and without luminal flow could identify new potential therapeutic pathways. Methods Fifteen paired human ileum samples were collected from children aged 2–20 months during ileostomy-reversal surgery after short-segment intestinal resection and diversion. The segment exposed to enteral feeding was denoted as fed, and the diverted segment was labeled as unfed. Morphometrics and cell differentiation were compared histologically. RNA Sequencing and Gene Ontology Enrichment Analysis identified over-represented and under-represented pathways. Immunofluorescence staining and Western blot evaluated proteins of interest. Paired data were compared with 1-tailed Wilcoxon rank-sum tests with a P value less than .05 considered significant. Results Unfed ileum contained shorter villi, shallower crypts, and fewer Paneth cells. Genes up-regulated by the absence of mechanoluminal stimulation were involved in digestion, metabolism, and transport. Messenger RNA expression of LGR5 was significantly higher in unfed intestine, accompanied by increased levels of phosphorylated signal transducer and activator of transcription 3 protein, and CCND1 and C-MYC messenger RNA. However, decreased proliferation and fewer LGR5+, OLFM4+, and SOX9+ intestinal stem cells (ISCs) were observed in unfed ileum. Conclusions Even with sufficient systemic caloric intake, human ileum responds to the chronic absence of mechanoluminal stimulation by up-regulating brush-border enzymes, transporters, structural genes, and ISC genes LGR5 and ASCL2. These data suggest that unfed intestine is primed to replenish the ISC population upon re-introduction of enteral feeding. Therefore, the elucidation of pathways involved in these processes may provide therapeutic targets for patients with intestinal failure. RNA sequencing data are available at Gene Expression Omnibus series GSE82147.

Lactobacillus murinus HF12 colonizes neonatal gut and protects rats from necrotizing enterocolitis

The use of lactobacilli in prevention of necrotizing enterocolitis (NEC) is hampered by insufficient knowledge about optimal species/strains and effects on intestinal bacterial populations. We therefore sought to identify lactobacilli naturally occurring in postnatal rats and examine their ability to colonize the neonatal intestine and protect from NEC. L. murinus, L. acidophilus, and L. johnsonii were found in 42, 20, and 1 out of 51 4-day old rats, respectively. Higher proportion of L. murinus in microbiota correlated with lower NEC scores. Inoculation with each of the three species during first feeding significantly augmented intestinal populations of lactobacilli four days later, indicating successful colonization. L. murinus, but not L. acidophilus or L. johnsonii, significantly protected against NEC. Thus, lactobacilli protect rats from NEC in a species- or strain-specific manner. Our results may help rationalizing probiotic therapy in NEC.

Inhibition of Fgf signaling in short bowel syndrome increases weight loss and epithelial proliferation

Background. Signaling by fibroblast growth factor is critical for epithelial proliferation, differentiation, and the development of many organs, including the intestine. Fibroblast growth factor 10 and fibroblast growth factor 2c are upregulated after massive bowel resection during intestinal adaptation. This pathway is conserved highly. We hypothesized that inhibition of fibroblast growth factor signaling would impair intestinal adaptation in the zebrafish model of short bowel syndrome and allow insight into the negative regulation of this pathway. Methods. Short bowel syndrome equivalent to a high jejunostomy was generated in adult male hsp70:dnfgfr1‐GFP zebrafish, wildtype fish exposed to tyrosine‐kinase inhibitor, and wildtype fish in absence of tyrosine‐kinase inhibitor. Heat shock in hsp70:dnfgfr1‐GFP fish decreases fgf 1 expression. Parameters including weight, proliferation, and differentiation were evaluated after harvest in experimental and control groups. Results. Although short bowel syndrome zebrafish lost more weight relative to sham zebrafish in both groups, heat shock fish with short bowel syndrome lost more weight compared with non‐heat shock fish with short bowel syndrome. In the non‐heat shock controls, the villus epithelial perimeter increased in short bowel syndrome compared with sham fish, but this did not occur in heat shock fish. Non‐heat shock fish with short bowel syndrome fish had significantly increased Bromodeoxyuridine(+) proliferative cells per hemivillus compared with non‐heat shock‐sham, while heat shock‐short bowel syndrome had a more substantial increase in Bromodeoxyuridine(+) cells compared with HS‐sham. Non‐heat shock‐short bowel syndrome demonstrated a significantly increased percentage of Alcian blue(+) goblet cells per hemivillus compared with non‐heat shock‐sham, while the heat shock‐short bowel syndrome demonstrated decreased Alcian blue(+) cells compared with non‐heat shock‐short bowel syndrome. In contrast, SU5402 inhibited epithelial proliferation while increasing weight loss. Conclusion. Inhibition of fibroblast growth factor‐1 signaling in short bowel syndrome decreases epithelial adaptation, increases Bromodeoxyuridine‐labeled cells at 2 weeks, and exacerbates weight loss while decreasing epithelial goblet cells.

Intestinal adaptation in proximal and distal segments: Two epithelial responses diverge after intestinal separation

Background. In short bowel syndrome, luminal factors influence adaptation in which the truncated intestine increases villus lengths and crypt depths to increase nutrient absorption. No study has evaluated the effect of adaptation within the distal intestine after intestinal separation. We evaluated multiple conditions, including Igf1r inhibition, in proximal and distal segments after intestinal resection to evaluate the epithelial effects of the absence of mechanoluminal stimulation. Methods. Short bowel syndrome was created in adult male zebrafish by performing a proximal stoma with ligation of the distal intestine. These zebrafish with short bowel syndrome were compared to sham‐operated zebrafish. Groups were treated with the Igf1r inhibitor NVP‐AEW541, DMSO, a vehicle control, or water for 2 weeks. Proximal and distal intestine were analyzed by hematoxylin and eosin for villus epithelial circumference, inner epithelial perimeter, and circumference. We evaluated BrdU+ cells, including costaining for &bgr;‐catenin, and the microbiome was evaluated for changes. Reverse transcription quantitative polymerase chain reaction was performed for &bgr;‐catenin, CyclinD1, Sox9a, Sox9b, and c‐Myc. Results. Proximal intestine demonstrated significantly increased adaptation compared to sham‐operated proximal intestine, whereas the distal intestine showed no adaptation in the absence of luminal flow. Addition of the Igf1r inhibitor resulted in decreased adaption in the distal intestine but an increase in distal proliferative cells and proximal &bgr;‐catenin expression. While some proximal proliferative cells in short bowel syndrome colocalized &bgr;‐catenin and BrdU, the distal proliferative cells did not co‐stain for &bgr;‐catenin. Sox9a increased in the distal limb after division but not after inhibition with the Igf1r inhibitor. There was no difference in alpha diversity or species richness of the microbiome between all groups. Conclusion. Luminal flow in conjunction with short bowel syndrome significantly increases intestinal adaption within the proximal intestine in which proliferative cells contain &bgr;‐catenin. Addition of an Igf1r inhibitor decreases adaptation in both proximal and distal limbs while increasing distal proliferative cells that do not colocalize &bgr;‐catenin. Igf1r inhibition abrogates the increase in distal Sox9a expression that otherwise occurs in short bowel syndrome. Mechanoluminal flow is an important stimulus for intestinal adaptation.

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

BACKGROUND With the advent of minimally invasive techniques, laparoscopic Ladds 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 Ladds procedure. METHODS We conducted a 5-y retrospective chart review of all patients who underwent Ladds 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 Ladds 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 Ladds 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 Ladds 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.

Soybean-derived recombinant human epidermal growth factor protects against experimental necrotizing enterocolitis

BACKGROUND Epidermal Growth Factor (EGF) reduces necrotizing enterocolitis (NEC). However, its high cost virtually prohibits clinical use. To reduce cost, soybean expressing human EGF was developed. Here we report effectiveness of soybean-derived EGF in experimental NEC. METHODS Newborn rats were subjected to the NEC-inducing regimen of formula feeding and hypoxia. Formula was supplemented with extract from EGF-expressing or empty soybeans. NEC pathology was determined microscopically. Localization of tight junction proteins JAM-A and ZO-1 was examined by immunofluorescence and levels of mucosal COX-2 and iNOS mRNAs by real time PCR. RESULTS Soybean extract amounts corresponding to 150μg/kg/day EGF caused considerable mortality, whereas those corresponding to 75μg/kg/day EGF were well tolerated. There was no significant difference in NEC scores between animals fed plain formula and formula supplemented with empty soybean extract. Soybean-EGF-supplemented formula at 75μg/kg/day EGF significantly decreased NEC, attenuated dissociation of JAM-A and ZO-1 proteins from tight junctions, and reduced intestinal expression of COX-2 and iNOS mRNAs. CONCLUSION Supplementation with soybean-expressed EGF significantly decreased NEC in the rat model. Soybean-expressed EGF may provide an economical solution for EGF administration and prophylaxis of clinical NEC.

Discussion of: “Hospital admission unnecessary for successful uncomplicated radiographic reduction of pediatric intussusception”

DR. RONALD SING (Charlotte, NC): As amatter of disclosure, I am not a pediatric surgeon. I have a pediatric hospital right next to me, so these go right there. I did have the opportunity to speak with four separate pediatric surgeons to get some background. Obviously, I was forced to do my own literature research review to catch up on this. So its very interesting, and I think that although this is not a novel concept, I do believe its good research and good science to confirm other findings, particularly looking at the resources that you have in your own institution, which becomes very important to make sure that your outcomes are the same as others, so I applaud you for following up and examining this particular topic. However, there are a couple of things as you talk about resources. Your facility is in an inner city area which is probably a pretty short time period of transport for the patients to have to return to the hospital. One of my questions is, what do you do in a more rural area where the child lives an hour away from the hospital, or two hours away from the hospital, which is not unexpected in my state of North Carolina? The two-to four-hour issue you began to clarify a little bit more, which is one of my questions. But does that twoor four-hour time period start from the time of the reduction or the completion of the reduction? And is two hours actually enough? Can we pick a number, either two or four hours? For us, that would be an important distinction for us to do that. You did clarify some questions I had about cost and charges which are obviously always difficult to do. Starting the protocol, which I really find interesting, was a surgeon or some pediatric surgical person present during the procedure, or were they home, and could this whole thing be done by