Accuracy of the American College of Surgeons Minimum Criteria for Full Trauma Team Activation for Children.

OBJECTIVE: Pediatric trauma centers use reports from emergency medical service providers to determine if a trauma team should be sent to the emergency department to prepare to care for the patient. Little scientific evidence supports the current American College of Surgeons (ACS) indicators for trauma team activation. The objective of this study was to determine the accuracy of the ACS Minimum Criteria for Full Trauma Team Activation for children as well as the accuracy of the modified criteria used at the local sites for trauma activation. METHODS: Emergency medical service providers who transported an injured child aged 15 years or younger to a pediatric trauma center in 1 of 3 cities were interviewed after emergency department arrival. Emergency medical service providers were asked if each of the activation indicators were present based on their evaluation. The need for full trauma team activation was determined through a medical record review using a published criterion standard definition. Undertriage and overtriage rates and positive likelihood ratios (+LRs) were calculated. RESULTS: Emergency medical service provider interviews were conducted and outcome data were obtained for 9483 children. There were 202 (2.1%) cases that met the criterion standard for need for trauma team activation. Based on the ACS Minimum Criteria, 299 (3.0%) cases should have received a trauma activation. The ACS Minimum Criteria undertriaged 44.1% and overtriaged 20% (+LR, 27.9; 95% confidence interval, 23.1-33.7). Based on the actual activation status using the local criteria, 238 cases received a full trauma activation, 45% were undertriaged, and 1.4% were overtriaged (+LR, 40.1; 95% confidence interval, 32.4-49.7). There was 97% agreement between the ACS Minimum Criteria and the actual local activation status at the receiving institution. CONCLUSIONS: The ACS Minimum Criteria for Full Trauma Team Activation for children have a high rate of undertriage. Changes that individual institutions have made to improve the accuracy of activations at their institutions seem to have had a limited effect on decreasing undertriage.

Imaging of Right Lower Quadrant Pain in Children and Adolescents: AJR Expert Panel Narrative Review.

Right lower quadrant (RLQ) pain is a common clinical presentation in children, and accurate clinical diagnosis remains challenging given that this nonspecific presentation is associated with numerous surgical and nonsurgical conditions. The broad differential diagnosis varies by patient age and sex. Important considerations in the selection of a diagnostic imaging strategy include the sequencing, performance, and cost of tests. This article provides a comprehensive narrative review of the diagnostic imaging of RLQ pain in children and adolescents, including a discussion of the complementary roles of ultrasound, CT, and MRI; description of key imaging findings based on available evidence; and presentation of salient differential diagnoses. Subspecialized pediatric emergency medicine and surgical perspectives are also provided as further clinical insight into this common, but often challenging, scenario. Finally, the current status of imaging of RLQ pain in children and adolescents is summarized on the basis of expert consensus.

Lipofibromatosis-like neural tumors: Report of a case and review of 73 reported cases.

Lipofibromatosis-like neural tumors (LPF-NTs) are a recently discovered group of spindle cell tumors defined by the presence of a lipofibromatosis-like pattern, CD34 and/or S100 reactivity, and frequent neurotrophic receptor tyrosine kinase 1 (NTRK1) gene rearrangements. As new cases emerge, the spectrum of features observed in LPF-NTs continues to evolve. Here we describe the case of an 11-year-old with LPF-NT with a dermatofibrosarcoma protuberans-like honeycomb pattern, CD34 and S100 co-expression, and an NTRK1 rearrangement. We also review the clinical and molecular features of the 73 cases of LPF-NT previously described in the literature.

Utilizing Near-Infrared Spectroscopy to Identify Pediatric Trauma Patients Needing Lifesaving Interventions: A Prospective Study.

OBJECTIVES: The aim of this study was to prospectively investigate the role of near-infrared spectroscopy (NIRS) in identifying pediatric trauma patients who required lifesaving interventions (LSIs). METHODS: Prospective cohort study of children age 0 to 18 years who activated the trauma team response between August 15, 2017, and February 12, 2019, at a large, urban pediatric emergency department (ED).The relationship between the lowest somatic NIRS saturation and the need for LSIs (based on published consensus definition) was investigated. Categorical variables were analyzed by χ 2 test, and continuous variables were analyzed by Student t test. RESULTS: A total of 148 pediatric trauma patients had somatic NIRS monitoring and met the inclusion criteria. Overall, 65.5% were male with a mean ± SD age of 10.9 ± 6.0 years. Injuries included 67.6% blunt trauma and 28.4% penetrating trauma with mortality of 3.4% (n = 5). Overall, the median lowest somatic NIRS value was 72% (interquartile range, 58%-88%; range, 15%-95%), and 43.9% of patients had a somatic NIRS value <70%. The median somatic NIRS duration recorded was 11 minutes (interquartile range, 7-17 minutes; range, 1-105 minutes). Overall, 36.5% of patients required a LSI including 53 who required a lifesaving procedure, 17 required blood products, and 17 required vasopressors. Among procedures, requiring a thoracostomy was significant.Pediatric trauma patients with a somatic NIRS value <70% had a significantly increased odds of requiring a LSI (odds ratio, 2.11; 95% confidence interval, 1.07-4.20). Somatic NIRS values <70% had a sensitivity and specificity of 56% and 63%, respectively. CONCLUSIONS: Pediatric trauma patients with somatic NIRS values <70% within 30 minutes of ED arrival have an increased odds of requiring LSIs. Among LSIs, pediatric trauma patients requiring thoracostomy was significant. The role of NIRS in incrementally improving the identification of critically injured children in the ED and prehospital setting should be evaluated in larger prospective multicenter studies.

Utilization and Adequacy of Telemedicine for Outpatient Pediatric Surgical Care.

INTRODUCTION: Telemedicine (TM) use accelerated out of necessity during the COVID-19 pandemic, but the utility of TM within the pediatric surgery population is unclear. This study measured utilization, adequacy, and disparities in uptake of TM in pediatric surgery during the COVID-19 pandemic. METHODS: Scheduled outpatient pediatric surgery clinic encounters at a large academic children's hospital from January 2020 through March 2021 were reviewed. Sub-group analysis examined post-operative (PO) visits after appendectomy and umbilical, epigastric, and inguinal hernia repairs. RESULTS: Of 9149 scheduled visits, 87.9% were in-person and 12.1% were TM. TM visits were scheduled for PO care (76.9%), new consultations (7.1%), and established patients (16.0%). Although TM visits were more frequently canceled or no shows (P < 0.001), most canceled TM visits were PO visits, of which 41.7% were canceled via electronic communication reporting the absence of any PO concerns. TM visits were adequate for accomplishing visit goals in 98.2%, 95.5%, and 96.2% of PO, new, and established patient visits, respectively. Patients utilizing TM visits were more frequently of white race, privately-insured, from less disadvantaged neighborhoods, and living a greater distance from clinic (P < 0.001 for all comparisons). CONCLUSIONS: TM was adequate for the majority of visits in which it was utilized, including the basic PO visits that occurred via TM. TM was used more by patients with greater travel and less by those of minority race, with public insurance, and from more disadvantaged neighborhoods. Future work is necessary to ensure broad access to this useful tool for all children requiring surgical care.

Assessment of MRI and Ultrasound Screening for Tethered Cord Syndrome in Patients Diagnosed With Esophageal Atresia/Tracheoesophageal Fistula.

INTRODUCTION: Infants with esophageal atresia and/or tracheoesophageal fistula (EA/TEF) undergo screening for tethered cord syndrome (TCS) via ultrasound and magnetic resonance imaging. Existing literature lacks data to guide optimal timing of screening and magnetic resonance imaging (MRI) is often delayed until 3-6 mo of age, when it is frequently forgotten. Detethering surgery has a high rate of success in patients with TCS and is often performed prophylactically due to potential irreversible deficits. This study aims to improve screening procedure for infants with EA/TEF. METHODS: A retrospective chart review was done of all EA/TEF patients treated over 6 y (n = 79). The study examined how often each imaging modality was performed and identified a TCS lesion, as well as age of screening/surgical intervention. RESULTS: Screening for TCS was done with MRI 58% of the time and US 15% of the time. However, 38% of patients did not undergo any screening. Out of the patients with TCS on MRI (n = 19, 41.3%), 73.7% had neurosurgery. Of patients who underwent ultrasound (US) (n = 12), nine patients also had MRI later: two reported TCS lesions and subsequently had neurosurgery. Surgical infection rates and complications were 0/14. CONCLUSIONS: MRI demonstrated a higher rate of detecting TCS lesions than US, and patients with TCS frequently had detethering. Patients with ≥3 VACTERL or vertebral anomalies had a higher incidence of TCS on MRI. Patients with vertebral anomalies reported false negative ultrasounds in two cases, suggesting the potential superiority of MRI screening in this subgroup. A third of children did not undergo any imaging and this will require a process improvement.

Utilizing Near-Infrared Spectroscopy (NIRS) to Identify Pediatric Trauma Patients Needing Lifesaving Interventions (LSIs): A Retrospective Study.

OBJECTIVES: The aim of this study was to investigate the role of near-infrared spectroscopy (NIRS) in identifying pediatric trauma patients who required lifesaving interventions (LSIs). METHODS: Retrospective chart review of children age 0 to 18 years who activated the trauma team response between January 1, 2015 and August 14, 2017, at a large, urban pediatric emergency department. The lowest somatic NIRS saturation and the need for LSIs (based on published consensus definition) were abstracted from the chart. χ2 and descriptive statistics were used for analysis. RESULTS: The charts of 84 pediatric trauma patients were reviewed. Overall, 80% were boys with a mean age of 10.4 years (SD, 6.2 years). Injuries included 56% blunt trauma and 36% penetrating trauma with mortality of 10.7% (n = 9). Overall, the median lowest NIRS value was 67% (interquartile range, 51-80%; range, 15%-95%) and 54.8% of the patients had a NIRS value less than 70%. The median somatic NIRS duration recorded was 12 minutes (interquartile range, 6-17 minutes; range, 1-59 minutes). Overall, 50% of patients required a LSI, including 39 who required a lifesaving procedure, 11 required blood products, and 14 required vasopressors. Pediatric trauma patients with NIRS less than 70% had a significantly increased odds of requiring a LSI (odds ratio, 2.67; 95% confidence interval, 1.10-6.47). NIRS less than 70% had a sensitivity and specificity of 67% and 57% respectively. CONCLUSIONS: Pediatric trauma patients with somatic NIRS less than 70% within 30 minutes of emergency department arrival are associated with the need for LSIs. Continuous NIRS monitoring in the pediatric trauma population should be evaluated prospectively.

Does Mechanism of Injury Predict Trauma Center Need for Children?

OBJECTIVE: To determine if the Mechanism of Injury Criteria of the Field Triage Decision Scheme (FTDS) are accurate for identifying children who need the resources of a trauma center. METHODS: EMS providers transporting any injured child ≤15 years, regardless of severity, to a pediatric trauma center in 3 midsized communities over 3 years were interviewed. Data collected through the interview included EMS observed physiologic condition, suspected anatomic injuries, and mechanism. Patients were then followed to determine if they needed the resources of a trauma center by reviewing their medical record after hospital discharge. Patients were considered to need a trauma center if they received an intervention included in a previously published consensus definition. Data were analyzed with descriptive statistics including positive likelihood ratios (+LR) and 95% confidence intervals (95%CI). RESULTS: 9,483 provider interviews were conducted and linked to hospital outcome data. Of those, 230 (2.4%) met the consensus definition for needing a trauma center. 1,572 enrolled patients were excluded from further analysis because they met the Physiologic or Anatomic Criteria of the FTDS. Of the remaining 7,911 cases, 62 met the consensus definition for needing a trauma center (TC). Taken as a whole, the Mechanism of Injury Criteria of the FTDS identified 14 of the remaining 62 children who needed the resources of a trauma center for a 77% under-triage rate. The mechanisms sustained were 36% fall (16 needed TC), 28% motor vehicle crash (MVC) (20 needed TC), 7% struck by a vehicle (10 needed TC), <1% motorcycle crash (none needed TC), and 29% had a mechanism not included in the FTDS (16 needed TC). Of those who sustained a mechanisms not listed in the FTDS, the most common mechanisms were sport related injuries not including falls (24% of 2,283 cases with a mechanism not included) and assault (13%). Among those who fell from a height greater than 10 feet, 4 needed a TC (+LR 5.9; 95%CI 2.8-12.6). Among those in a MVC, 41 were reported to have been ejected and none needed a TC, while 31 had reported meeting the intrusion criteria and 0 needed a TC. There were 32 reported as having a death in the same vehicle, and 2 needed a TC (+LR 7.42; 95%CI: 1.90-29.0). CONCLUSION: Over a quarter of the children who needed the resources of a trauma center were not identified using the Physiologic or Anatomic Criteria of the Field Triage Decision Scheme. The Mechanism of Injury Criteria did not apply to over a quarter of the mechanisms experienced by children transported by EMS for injury. Use of the Mechanism Criteria did not greatly enhance identification of children who need a trauma center. More work is needed to improve the tool used to assist EMS providers in the identification of children who need the resources of a trauma center.

Venous thromboembolism prophylaxis after pediatric trauma.

In recent years, there has been an increased focus on developing and validating venous thromboprophylaxis guidelines in the pediatric trauma population. We review the current literature regarding the incidence of and risk factors for venous thromboembolism (VTE) and the use of prophylaxis in the pediatric trauma population. Risk factors such as age, injury severity, central venous catheters, mental status, injury type, surgery, and comorbidities can lead to a higher incidence of VTE. Risk stratification tools have been developed to determine whether mechanical and/or pharmacologic prophylaxis should be implemented depending on the degree of VTE risk. When VTE risk is high, pharmacologic prophylaxis, such as with low molecular weight heparin, is often initiated. However, the timing and duration of VTE prophylaxis is dependent on patient factors including ambulatory status and contraindications such as bleeding. In addition, the utility of screening ultrasound for VTE surveillance has been evaluated and though they are not widely recommended, no formal guidelines exist. While more research has been done in recent years to assess the most appropriate type, timing, and duration of VTE prophylaxis, further studies are warranted to create optimal guidelines for decreasing the risk of VTE after pediatric trauma.

COVID-19 pre-procedural testing strategy and early outcomes at a large tertiary care children's hospital.

PURPOSE: With the emergence of the coronavirus disease-2019 (COVID-19) pandemic, institutions were tasked with developing individualized pre-procedural testing strategies that allowed for re-initiation of elective procedures within national and state guidelines. This report describes the experience of a single US children's hospital (Children's Wisconsin, CW) in developing a universal pre-procedural COVID-19 testing protocol and reports early outcomes. METHODS: The CW pre-procedural COVID-19 response began with the creation of a multi-disciplinary taskforce that sought to develop a strategy for universal pre-procedural COVID-19 testing which (1) maximized patient safety, (2) prevented in-hospital viral transmission, (3) conserved resources, and (4) allowed for resumption of procedural care within institutional capacity. RESULTS: Of 11,209 general anesthetics performed at CW from March 16, 2020 to October 31, 2020, 11,150 patients (99.5%) underwent pre-procedural COVID-19 testing. Overall, 1.4% of pre-procedural patients tested positive for COVID-19. By June 2020, CW was operating at near-normal procedural volume and there were no documented cases of in-hospital viral transmission. Only 0.5% of procedures were performed under augmented COVID-19 precautions (negative pressure environment and highest-level personal protective equipment). CONCLUSION: CW successfully developed a multi-disciplinary pre-procedural COVID-19 testing protocol that enabled resumption of near-normal procedural volume within three months while limiting in-hospital viral transmission and resource use.

Single-Immunoglobulin Interleukin-1-Related Receptor regulates vulnerability to TLR4-mediated necrotizing enterocolitis in a mouse model.

BackgroundThe mechanisms underlying aberrant activation of intestinal Toll-like receptor 4 (TLR4) signaling in necrotizing enterocolitis (NEC) remain unclear. In this study, we examined the role of single-immunoglobulin interleukin-1 receptor-related molecule (SIGIRR), an inhibitor of TLR signaling, in modulating experimental NEC vulnerability in mice.MethodsExperimental NEC was induced in neonatal wild-type and SIGIRR-/- mice using hypoxia, formula-feeding, and lipopolysaccharide administration. Intestinal TLR canonical signaling, inflammation, apoptosis, and severity of experimental NEC were examined at baseline and after NEC induction in mice.ResultsSIGIRR is developmentally regulated in the neonatal intestine with a restricted expression after birth and a gradual increase by day 8. At baseline, breast-fed SIGIRR-/- mouse pups exhibited low-grade inflammation and TLR pathway activation compared with SIGIRR+/+ pups. With experimental NEC, SIGIRR-/- mice had significantly more intestinal interleukin (IL)-1ß, KC (mouse homolog to IL-8), intercellular adhesion molecule-1 (ICAM-1), and interferon-beta (IFN-ß) expression in association with the amplified TLR pathway activation. Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining, cleaved caspase 3, and severity of intestinal injury with NEC were worse in SIGIRR-/- mice in comparison with SIGIRR+/+ mice.ConclusionSIGIRR is a negative regulator of TLR4 signaling in the developing intestine, and its insufficiency results in native intestinal TLR hyper-responsiveness conducive to the development of severe experimental NEC in mice.

Role of intestinal Hsp70 in barrier maintenance: contribution of milk to the induction of Hsp70.2.

BACKGROUND: Necrotizing enterocolitis (NEC) is a gastrointestinal disease of complex etiology resulting in devastating systemic inflammation and often death in premature newborns. We previously demonstrated that formula feeding inhibits ileal expression of heat shock protein-70 (Hsp70), a critical stress protein within the intestine. Barrier function for the premature intestine is critical. We sought to determine whether reduced Hsp70 protein expression increases neonatal intestinal permeability. METHODS: Young adult mouse colon cells (YAMC) were utilized to evaluate barrier function as well as intestine from Hsp70-/- pups (KO). Sections of intestine were analyzed by Western blot, immunohistochemistry, and real time PCR. YAMC cells were sub-lethally heated or treated with expressed milk (EM) to induce Hsp70. RESULTS: Immunostaining demonstrates co-localized Hsp70 and tight junction protein zona occludens-1 (ZO-1), suggesting physical interaction to protect tight junction function. The permeability of YAMC monolayers increases following oxidant injury and is partially blocked by Hsp70 induction either by prior heat stress or EM. RT-PCR analysis demonstrated that the Hsp70 isoforms, 70.1 and 70.3, predominate in WT pup; however, Hsp70.2 predominates in the KO pups. While Hsp70 is present in WT milk, it is not present in KO EM. Hsp70 associates with ZO-1 to maintain epithelial barrier function. CONCLUSION: Both induction of Hsp70 and exposure to EM prevent stress-induced increased permeability. Hsp70.2 is present in both WT and KO neonatal intestine, suggesting a crucial role in epithelial integrity. Induction of the Hsp70.2 isoform appears to be mediated by mother's milk. These results suggest that mother's milk feeding modulates Hsp70.2 expression and could attenuate injury leading to NEC. LEVEL OF EVIDENCE: Level III.

Intestinal alkaline phosphatase deficiency leads to dysbiosis and bacterial translocation in the newborn intestine.

BACKGROUND: Intestinal alkaline phosphatase (IAP) has been shown to help maintain intestinal homeostasis. Decreased expression of IAP has been linked with pediatric intestinal diseases associated with bacterial overgrowth and subsequent inflammation. We hypothesize that the absence of IAP leads to dysbiosis, with increased inflammation and permeability of the newborn intestine. METHODS: Sprague-Dawley heterozygote IAP cross-matches were bred. Pups were dam fed ad lib and euthanized at weaning. The microbiotas of terminal ileum (TI) and colon was determined by quantitative real-time polymerase chain reaction (qRT-PCR) of subphylum-specific bacterial 16S ribosomal RNA. RT-PCR was performed on TI for inflammatory cytokines. Intestinal permeability was quantified by fluorescein isothiocyanate-dextran permeability and bacterial translocation by qRT-PCR for bacterial 16S ribosomal RNA in mesenteric lymph nodes. Statistical analysis was done by chi-square analysis. RESULTS: All three genotypes had similar concentrations of bacteria in the TI and colon. However, IAP knockout (IAP-KO) had significantly decreased diversity of bacterial species in their colonic stool compared with heterozygous and wild-type (WT). IAP-KO pups had a nonstatistically significant 3.9-fold increased inducible nitric oxide synthase messenger RNA expression compared with WT (IAP-KO, 3.92 ± 1.36; WT, 1.0 ± 0.27; P = 0.03). IAP-KO also had significantly increased bacterial translocation to mesenteric lymph nodes occurred in IAP-KO (IAP-KO, 7625 RFU/g ± 3469; WT, 4957 RFU/g ± 1552; P = 0.04). Furthermore, IAP-KO had increased permeability (IAP-KO, 0.297 mg/mL ± 0.2; WT, 0.189 mg/mL ± 0.15 P = 0.07), but was not statistically significant. CONCLUSIONS: Deficiency of IAP in the newborn intestine is associated with dysbiosis and increased inflammation, permeability, and bacterial translocation.

Intestinal alkaline phosphatase: a summary of its role in clinical disease.

Over the past few years, there is increasing evidence implicating a novel role for Intestinal Alkaline Phosphatase (IAP) in mitigating inflammatory mediated disorders. IAP is an endogenous protein expressed by the intestinal epithelium that is believed to play a vital role in maintaining gut homeostasis. Loss of IAP expression or function is associated with increased intestinal inflammation, dysbiosis, bacterial translocation and subsequently systemic inflammation. As these events are a cornerstone of the pathophysiology of many diseases relevant to surgeons, we sought to review recent research in both animal and humans on IAP's physiologic function, mechanisms of action and current research in specific surgical diseases.

Intestinal alkaline phosphatase to treat necrotizing enterocolitis.

BACKGROUND: Intestinal alkaline phosphatase (IAP) activity is decreased in necrotizing enterocolitis (NEC), and IAP supplementation prevents NEC development. It is not known if IAP given after NEC onset can reverse the course of the disease. We hypothesized that enteral IAP given after NEC induction would not reverse intestinal injury. MATERIALS AND METHODS: NEC was induced in Sprague-Dawley pups by delivery preterm followed by formula feedings with lipopolysaccharide (LPS) and hypoxia exposure and continued up to 4 d. IAP was added to feeds on day 2 until being sacrificed on day 4. NEC severity was scored based on hematoxylin and eosin-stained terminal ileum sections, and AP activity was measured using a colorimetric assay. IAP and interleukin-6 expression were measured using real time polymerase chain reaction. RESULTS: NEC pups' alkaline phosphatase (AP) activity was decreased to 0.18 U/mg compared with controls of 0.57 U/mg (P < 0.01). Discontinuation of LPS and hypoxia after 2 d increased AP activity to 0.36 U/mg (P < 0.01). IAP supplementation in matched groups did not impact total AP activity or expression. Discontinuing LPS and hypoxia after NEC onset improved intestinal injury scores to 1.14 compared with continued stressors, score 2.25 (P < 0.01). IAP supplementation decreased interleukin-6 expression two-fold (P < 0.05), though did not reverse NEC intestinal damage (P = 0.5). CONCLUSIONS: This is the first work to demonstrate that removing the source of NEC improves intestinal damage and increases AP activity. When used as a rescue treatment, IAP decreased intestinal inflammation though did not impact injury making it likely that IAP is best used preventatively to those neonates at risk.

Inhibition of myeloperoxidase decreases vascular oxidative stress and increases vasodilatation in sickle cell disease mice.

Activated leukocytes and polymorphonuclear neutrophils (PMN) release myeloperoxidase (MPO), which binds to endothelial cells (EC), is translocated, and generates oxidants that scavenge nitric oxide (NO) and impair EC function. To determine whether MPO impairs EC function in sickle cell disease (SCD), control (AA) and SCD mice were treated with N-acetyl-lysyltyrosylcysteine-amide (KYC). SCD humans and mice have high plasma MPO and soluble L-selectin (sL-selectin). KYC had no effect on MPO but decreased plasma sL-selectin and malondialdehyde in SCD mice. MPO and 3-chlorotyrosine (3-ClTyr) were increased in SCD aortas. KYC decreased MPO and 3-ClTyr in SCD aortas to the levels in AA aortas. Vasodilatation in SCD mice was impaired. KYC increased vasodilatation in SCD mice more than 2-fold, to ∼60% of levels in AA mice. KYC inhibited MPO-dependent 3-ClTyr formation in EC proteins. SCD mice had high plasma alanine transaminase (ALT), which tended to decrease in KYC-treated SCD mice (P = 0.07). KYC increased MPO and XO/XDH and decreased 3-ClTyr and 3-nitrotyrosine (3-NO2Tyr) in SCD livers. These data support the hypothesis that SCD increases release of MPO, which generates oxidants that impair EC function and injure livers. Inhibiting MPO is an effective strategy for decreasing oxidative stress and liver injury and restoring EC function in SCD.

N-acetyl lysyltyrosylcysteine amide inhibits myeloperoxidase, a novel tripeptide inhibitor.

Myeloperoxidase (MPO) plays important roles in disease by increasing oxidative and nitrosative stress and oxidizing lipoproteins. Here we report N-acetyl lysyltyrosylcysteine amide (KYC) is an effective inhibitor of MPO activity. We show KYC inhibits MPO-mediated hypochlorous acid (HOCl) formation and nitration/oxidation of LDL. Disulfide is the major product of MPO-mediated KYC oxidation. KYC (≤4,000 µM) does not induce cytotoxicity in bovine aortic endothelial cells (BAECs). KYC inhibits HOCl generation by phorbol myristate acetate (PMA)-stimulated neutrophils and human promyelocytic leukemia (HL-60) cells but not superoxide generation by PMA-stimulated HL-60 cells. KYC inhibits MPO-mediated HOCl formation in BAEC culture and protects BAECs from MPO-induced injury. KYC inhibits MPO-mediated lipid peroxidation of LDL whereas tyrosine (Tyr) and tryptophan (Trp) enhance oxidation. KYC is unique as its isomers do not inhibit MPO activity, or are much less effective. Ultraviolet-visible spectral studies indicate KYC binds to the active site of MPO and reacts with compounds I and II. Docking studies show the Tyr of KYC rests just above the heme of MPO. Interestingly, KYC increases MPO-dependent H2O2 consumption. These data indicate KYC is a novel and specific inhibitor of MPO activity that is nontoxic to endothelial cell cultures. Accordingly, KYC may be useful for treating MPO-mediated vascular disease.

Intestinal alkaline phosphatase prevents the systemic inflammatory response associated with necrotizing enterocolitis.

BACKGROUND: Necrotizing enterocolitis (NEC) is the most common surgical emergency in neonates, with an incidence of 0.5-2.4 cases per 1000 live births and a mortality rate between 10% and 50%. Neonates affected by NEC develop a septic injury that is associated with increased risk of neurological impairment due to intraventricular bleeding and chronic lung disease. Intestinal alkaline phosphatase (IAP) is an endogenous protein that has been shown to inactivate the endotoxin lipopolysaccharide (LPS), and has recently been used successfully as an adjunct to treat sepsis in adult patients. We tested the hypothesis that systemic, exogenous IAP will mitigate the inflammatory response as measured by serum levels of proinflammatory cytokines in a rat model of NEC. METHODS: Newborn Sprague-Dawley rats were divided into groups. Control pups were dam fed. NEC was induced by feeding formula containing LPS and exposure to intermittent hypoxia. NEC pups were given intraperitoneal injections of 4 or 40 glycine units (U) of IAP or placebo twice daily. Intestine and serum was collected for cytokine analysis as well as measurement of alkaline phosphatase activity. RESULTS: Systemic IAP administration significantly increased serum alkaline phosphatase activity in a dose- and time-dependent fashion. The proinflammatory cytokines tumor necrosis factor α, interleukin 6, and interleukin 1ß were significantly increased in NEC rats versus controls on days 2 and 3. Importantly, treatment with 40 U systemic IAP decreased these proinflammatory cytokines back to near-control levels. CONCLUSIONS: Systemic IAP administration appears effective in mitigating the systemic inflammatory response associated with NEC, and may prove to be a valuable adjunctive treatment for NEC.