The Spectrum of Sarcina Colonization in the Gastrointestinal Tract of Pediatric and Adolescent Patients.

Introduction. Sarcina organisms are rare, gram-positive, sugar-fermenting cocci, identifiable in tissues only by histologic examination or molecular testing. Since its discovery, the pathogenicity and relevance of Sarcina in the human gastrointestinal tract has remained ill-defined. A recent literature review of 66 reported examples demonstrated the potential for severe complications such as emphysematous gastritis and gastric perforation. In pediatrics, colonization is associated with mucosal alterations and/or gastrointestinal dysmotility/obstruction with variable outcomes, including death secondary to gastric perforation. Yet, the features of Sarcina colonization within the gastrointestinal tract of adolescents are poorly understood and rarely reported. Methods. We present the gastrointestinal histopathological findings and the complete history of 4 pediatric patients with Sarcina colonization at our institution. Additionally a literature review with focus in the keywords "Sarcina" and "gastrointestinal' was performed, and the clinical and histopathological features of all previously reported examples of Sarcina in the gastrointestinal tract of pediatric patients were summarized. Results. All 4 patients had delayed gastric emptying, 3 of them due to neurologic disease, and one with pyloric obstruction due to duodenal ulceration with Helicobacter gastritis. In the 3 patients with available esophageal biopsies, it was associated to esophagitis with increased intraepithelial eosinophils. Conclusion. The potential pathogenicity of Sarcina colonization in the gastrointestinal tract of pediatric patients needs to be reevaluated. Due to potential serious complications, the identification of these organisms in the gastrointestinal tract sample should be reported and warrants further evaluation for possible gastrointestinal dysmotility or other mucosal alterations.

Pelvic Neuroblastoma of the Pediatric Prostate.

Neuroblastoma accounts for a significant portion of childhood tumors and can present in a variety of ways. Pelvic neuroblastoma has been reported but few cases exist of neuroblastoma invading or originating from the bladder or prostate. We present a 4-year-old patient with pelvic neuroblastoma arising from the prostate and describe the medical and surgical management of this challenging case. While pelvic neuroblastoma may have an improved prognosis, this case demonstrates the challenging surgical decisions that accompany these patients to maintain quality of life while balancing oncologic efficacy of treatment.

Early Ventilator Management for Infants With Congenital Diaphragmatic Hernia: Impact of a Standardized Clinical Practice Guideline.

BACKGROUND: Infants with congenital diaphragmatic hernia (CDH) experience high morbidity and mortality due to pulmonary arterial hypertension and hypoplasia. Mechanical ventilation is a central component of CDH management. Our objective was to evaluate the impact of a standardized clinical practice guideline (implemented in January 2012) on ventilator management for infants with CDH, and associate management changes with short-term outcomes, specifically extracorporeal membrane oxygenation (ECMO) utilization and survival to discharge. METHODS: We conducted a retrospective pre-post study of 103 CDH infants admitted from January 2007-July 2021, divided pre- (n = 40) and post-guideline (n = 63). Clinical outcomes, ventilator settings, and blood gas values in the first 7 days of mechanical ventilation were compared between the pre- and post-guideline cohorts. RESULTS: Post-guideline, ECMO utilization decreased (11% vs 38%, p = 0.001) and survival to discharge improved (92% vs 68%, p = 0.001). More post-guideline patients remained on conventional mechanical ventilation without need for escalation to high-frequency ventilation or ECMO, and had higher pressures and PaCO2 with lower FiO2 and PaO2 (p < 0.05). CONCLUSIONS: Standardized ventilator management optimizing pressures for adequate lung expansion and minimizing oxygen toxicity improves outcomes for infants with CDH. LEVEL OF EVIDENCE: III.

Antibiotic therapy and necrotizing enterocolitis.

Antibiotic therapy remains a cornerstone of treatment of both medical and surgical presentations of necrotizing enterocolitis (NEC). However, guidelines regarding the administration of antibiotics for the treatment of NEC are lacking and practices vary amongst clinicians. Although the pathogenesis of NEC is unknown, there is consensus that the infant gastrointestinal microbiome contributes to the disease. The presumed connection between dysbiosis and NEC has prompted some to study whether early prophylactic enteral antibiotics can prevent NEC. Yet others have taken an opposing approach, studying whether perinatal antibiotic exposure increases the risk of NEC by inducing a state of dysbiosis. This narrative review summarizes what is known about antibiotics and their association with the infant microbiome and NEC, current antibiotic prescribing practices for infants with medical and surgical NEC, as well as potential strategies to further optimize the use of antibiotics in this population of infants.

Impact of a standardized management guideline for infants with CDH: A single-center experience.

BACKGROUND: Infants with congenital diaphragmatic hernia (CDH) are at high risk of death, even despite extracorporeal membrane oxygenation (ECMO) support. In January 2012 we implemented a standardized clinical practice guideline (CPG) to manage infants with CDH. We hypothesized that infants with CDH managed with CPG had better clinical outcomes, less ECMO utilization, and increased survival to discharge. METHODS: We conducted a retrospective pre-post study of infants with CDH admitted between January 2007 and July 2021 (n = 133). Patients were divided into Cohort 1, pre-CPG (January 2007 to December 2011, n = 54), and Cohort 2, post-CPG (January 2012 to July 2021, n = 79). RESULTS: More patients in Cohort 1 were small for gestational age than in Cohort 2. No other patient demographics were different between cohorts. Cohort 2 had significantly lower ECMO utilization as compared to Cohort 1 (18% vs 50%, p<0.001). Cohort 2 had significantly higher survival to discharge compared to Cohort 1 (85% vs 57%, p<0.001). Survival for ECMO-treated patients in Cohort 2 was significantly higher than in Cohort 1 (71% vs 26%, p = 0.005). In Cohort 1, 70% of the non-survivors were repaired, of which 81% were repaired on ECMO. In Cohort 2, 8% of the non-survivors were repaired, none on ECMO. Only 3% in Cohort 2 were discharged with pulmonary hypertension medication. CONCLUSIONS: A standardized CPG to manage patients with CDH decreased ECMO utilization and improved clinical outcomes including survival to discharge. Refinement of management strategies, implementation of new interventions, and meticulous care can improve outcomes in patients with CDH.

Utility of Postnatal Chest X-Ray in Newborns for the Evaluation of Prenatally Suspected Congenital Pulmonary Airway Malformation: A Single-Center Experience.

OBJECTIVE: The aim of the study is to assess the necessity of chest X-ray (CXR) during the newborn hospitalization for all patients with prenatally suspected congenital pulmonary airway malformation (CPAM). STUDY DESIGN: This is a retrospective chart review of all infants delivered with prenatally suspected CPAM at our high-risk delivery hospital from January 2013 through April 2020 (n = 44). Nonparametric tests assessed the association between postnatal CXR findings, prescribed follow-up timeline, and neonatal outcomes. RESULTS: Mean follow-up period recommended was 6.4 weeks regardless of CXR findings in the neonatal period (p = 0.81). Additionally, patients who required respiratory support at or after birth were not more likely to have a lesion identified on chest X-ray (odds ratio [OR] = 0.72, 95% confidence interval [CI], 0.18-2.64, p = 0.71). CONCLUSION: Neonatal hospital course and future follow-up plan of patients with prenatally suspected CPAM were not altered by information from the CXR obtained in the immediate neonatal period, suggesting that this CXR may not be necessary in the asymptomatic patient. KEY POINTS: · Immediate postnatal X-ray of prenatally diagnosed CPAM does not alter planned follow-up interval.. · Immediate postnatal X-ray does not alter surgical plan for CPAM.. · Postnatal X-ray is not absolutely required for asymptomatic newborns with CPAM..

Endotoxin Engages Mitochondrial Quality Control via an iNOS-Reactive Oxygen Species Signaling Pathway in Hepatocytes.

BACKGROUND: Organ injury and dysfunction in sepsis accounts for significant morbidity and mortality. Adaptive cellular responses in the setting of sepsis prevent injury and allow for organ recovery. We and others have shown that part of the adaptive response includes regulation of cellular respiration and maintenance of a healthy mitochondrial population. Herein, we hypothesized that endotoxin-induced changes in hepatocyte mitochondrial respiration and homeostasis are regulated by an inducible nitric oxide synthase/nitric oxide (iNOS/NO)-mitochondrial reactive oxygen species (mtROS) signaling axis, involving activation of the NRF2 signaling pathway. METHODS: Wild-type (C57Bl/6) or iNos-/- male mice were subjected to intraperitoneal lipopolysaccharide (LPS) injections to simulate endotoxemia. Individual mice were randomized to treatment with NO-releasing agent DPTA-NONOate, mtROS scavenger MitoTEMPO, or vehicle controls. Other mice were treated with scramble or Nrf2-specific siRNA via tail vein injection. Primary murine hepatocytes were utilized for in vitro studies with or without LPS stimulation. Oxygen consumption rates were measured to establish mitochondrial respiratory parameters. Western blotting, confocal microscopy with immunocytochemistry, and rtPCR were performed for analysis of iNOS as well as markers of both autophagy and mitochondrial biogenesis. RESULTS: LPS treatment inhibited aerobic respiration in vitro in wild-type but not iNos -/- cells. Experimental endotoxemia in vivo or in vitro induced iNOS protein and mtROS production. However, induction of mtROS was dependent on iNOS expression. Furthermore, LPS-induced hepatic autophagy/mitophagy and mitochondrial biogenesis were significantly attenuated in iNos -/- mice or cells with NO or mtROS scavenging. These responses were rescued in iNos -/- mice via delivery of NO both in vivo and in vitro. Conclusions. These data suggest that regulation of mitochondrial quality control following hepatocyte LPS exposure is dependent at least in part on a NO-mtROS signaling network. Further investigation to identify specific agents that modulate this process may facilitate the prevention of organ injury in sepsis.

Heme Oxygenase-2 Localizes to Mitochondria and Regulates Hypoxic Responses in Hepatocytes.

Hypoxia occurs as a part of multiple disease states, including hemorrhagic shock. Adaptive responses occur within the cell to limit the consequences of hypoxia. This includes changes in mitochondrial respiration, stress-induced cell signaling, and gene expression that is regulated by hypoxia inducible factor-1α (HIF-1α). Heme oxygenase-2 (HO-2) has been shown to be involved in oxygen sensing in several cell types. The purpose of these experiments was to test the hypothesis that HO-2 is a critical regulator of mitochondrial oxygen consumption and reactive oxygen species (ROS) production to influence hypoxia-adaptive responses such as HIF-1α protein levels and JNK signaling. Methods and Results. In vitro studies were performed in primary mouse hepatocytes. HO-2, but not HO-1, was expressed in mitochondria at baseline. Decreased oxygen consumption and increased mitochondrial ROS production in response to hypoxia were dependent upon HO-2 expression. HO-2 expression regulated HIF-1α and JNK signaling in a mitochondrial ROS-dependent manner. Furthermore, knockdown of HO-2 led to increased organ damage, systemic inflammation, tissue hypoxia, and shock in a murine model of hemorrhage and resuscitation. Conclusion. HO-2 signaling plays a role in hypoxic signaling and hemorrhagic shock. This pathway may be able to be harnessed for therapeutic effects.

Blue Light Enhances Bacterial Clearance and Reduces Organ Injury During Sepsis.

OBJECTIVES: The physiology of nearly all mammalian organisms are entrained by light and exhibit circadian rhythm. The data derived from animal studies show that light influences immunity, and these neurophysiologic pathways are maximally entrained by the blue spectrum. Here, we hypothesize that bright blue light reduces acute kidney injury by comparison with either bright red or standard, white fluorescent light in mice subjected to sepsis. To further translational relevance, we performed a pilot clinical trial of blue light therapy in human subjects with appendicitis. DESIGN: Laboratory animal research, pilot human feasibility trial. SETTING: University basic science laboratory and tertiary care hospital. SUBJECTS: Male C57BL/6J mice, adult (> 17 yr) patients with acute appendicitis. INTERVENTIONS: Mice underwent cecal ligation and puncture and were randomly assigned to a 24-hour photoperiod of bright blue, bright red, or ambient white fluorescent light. Subjects with appendicitis were randomized to receive postoperatively standard care or standard care plus high-illuminance blue light. MEASUREMENTS AND MAIN RESULTS: Exposure to bright blue light enhanced bacterial clearance from the peritoneum, reduced bacteremia and systemic inflammation, and attenuated the degree of acute kidney injury. The mechanism involved an elevation in cholinergic tone that augmented tissue expression of the nuclear orphan receptor REV-ERBα and occurred independent of alterations in melatonin or corticosterone concentrations. Clinically, exposure to blue light after appendectomy was feasible and reduced serum interleukin-6 and interleukin-10 concentrations. CONCLUSIONS: Modifying the spectrum of light may offer therapeutic utility in sepsis.

Surgical Site Infections and Associated Operative Characteristics.

Surgical site infection (SSI) contributes significantly to surgical morbidity. Patient factors and operative factors contribute to the risk of development of SSI. This review focuses on understanding operative characteristics that are associated with an increased risk of SSI. Much attention has been given to protocol care to reduce SSI, such as hair removal, skin preparation, and pre-operative antibiotic agents. Even with this, the appropriate antibiotic and re-dosing regimens often remain a challenge. Other operative factors such as blood loss/transfusion, emergency/urgent cases, duration of the operation, type of anesthesia, and resident involvement are also potentially modifiable to reduce the risk of SSI. Data are reviewed to highlight the increased risk associated with such factors. Strategies to reduce risk, such as operative care bundles, have significant promise to reduce the incidence of SSI for any given procedure.

Sepsis results in an altered renal metabolic and osmolyte profile.

BACKGROUND: Sepsis remains a major health-care burden and source of morbidity and mortality. Acute kidney injury and failure frequently accompanies severe sepsis and contributes to this burden. Despite a great deal of research, the exact mechanisms underlying renal failure in sepsis are poorly understood. This study aims to further understand metabolic changes in renal tissue during sepsis. MATERIALS AND METHODS: Experimental sepsis was induced by cecal ligation and puncture (CLP) in C57BL/6 mice. Serum and organs were harvested 8 h after CLP. Markers of renal function including serum creatinine, blood urea nitrogen, and cystatin C were measured. Whole kidneys were analyzed for a global biochemical profile via liquid chromatography/tandem mass spectrometry by Metabolon. RESULTS: CLP induced renal injury as evidenced by elevated serum creatinine, blood urea nitrogen, and cystatin C. Global energetic profile in sepsis showed an increase in glycolytic intermediates with decreased flux through the tricarboxylic acid (TCA) cycle. Multiple inflammatory markers were elevated in response to CLP. Levels of osmotic regulators varied, with an overall increase in pinitol, urea, and taurine in response to CLP. CONCLUSIONS: CLP resulted in dramatic changes in the renal macromolecular milieu. There appears to be an increased dependence on glycolysis and diminished flush through the TCA cycle. In addition, changes in renal osmolytes including pinitol, urea, and taurine were observed, perhaps uncovering an additional change with implications on renal function during sepsis.

Novel therapies for severe Clostridium difficile colitis.

PURPOSE OF REVIEW: Clostridium difficile infection (CDI) is becoming a large healthcare burden with increasing incidence, high recurrence rates, and associated morbidity and mortality. Disease severity varies from mild to severe and complicated presentations. Current mainstays of therapy in severe CDI include: fluid resuscitation, support of organ dysfunction, discontinuation of inciting agents, and antibiotic treatment. RECENT FINDINGS: Recent focus on the impact of the microbiome and targeted therapies to reconstitute biodiversity may provide alternative therapeutic modalities with higher success and lower recurrence rates. Newer antibiotics are under development, along with targeted immunotherapies that attempt to neutralize pathogenic toxins. Alternative surgical options from traditional subtotal colectomy may provide a less morbid surgical option for those requiring intervention. SUMMARY: With further understanding of the pathogenesis and shortcomings of current therapies, the future of management of CDI may include a multimodal approach focusing on microbiota and immunologic therapies that could result in improved cure with reduced recurrence.

Nitrate/Nitrite as Critical Mediators to Limit Oxidative Injury and Inflammation.

SIGNIFICANCE: Nitric oxide (NO) is a critical signaling molecule marked by complex chemistry and varied biological responses depending on the context of the redox environment. In the setting of inflammation, NO can not only contribute to tissue injury and be causative of oxidative damage but can also signal as an adaptive molecule to limit inflammatory signaling in multiple cell types and tissues. RECENT ADVANCES: An advance in our understanding of NO biology was the recognition of the nitrate-nitrite-NO axis, whereby nitrate (predominantly from dietary sources) could be converted to nitrite and nitrite could be reduced to NO. CRITICAL ISSUES: Intriguingly, the recognition of multiple enzymes that serve as nitrite reductases in the setting of hypoxia or ischemia established the concept of nitrite as a circulating endocrine reservoir of NO, with the selective release of NO at sites that were primed for this reaction. This review highlights the anti-inflammatory roles of nitrite in numerous clinical conditions, including ischemia/reperfusion, transplant, cardiac arrest, and vascular injury, and in gastrointestinal inflammation. FUTURE DIRECTIONS: These preclinical and clinical investigations set up further clinical trials and studies that elucidate the endogenous role this pathway plays in protection against inflammatory signaling.

Sirtuin 1 Agonist Minimizes Injury and Improves the Immune Response Following Traumatic Shock.

Survival from traumatic injury requires a coordinated and controlled inflammatory and immune response. Mitochondrial and metabolic responses to stress have been shown to play a role in these inflammatory and immune responses. We hypothesized that increases in mitochondrial biogenesis via a sirtuin 1 agonist would decrease tissue injury and partially ameliorate the immunosuppression seen following trauma. C57Bl/6 mice were subjected to a multiple trauma model. Mice were pretreated with either 100 mg/kg per day of the sirtuin 1 agonist, Srt1720, via oral gavage for 2 days prior to trauma and extended until the day the animals were killed, or they were pretreated with peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α) siRNA via hydrodynamic tail vein injection 48 h prior to trauma. Markers for mitochondrial function and biogenesis were measured in addition to splenocyte proliferative capacity and bacterial clearance. Srt1720 was noted to improve mitochondrial biogenesis, mitochondrial function, and complex IV activity following traumatic injury (P < 0.05), whereas knockdown of PGC1α resulted in exacerbation of mitochondrial dysfunction (P < 0.05). These changes in mitochondrial function were associated with altered severity of hepatic injury with significant reductions in serum alanine aminotransferase levels seen in mice treated with srt1720. Splenocyte proliferative capacity and intraperitoneal bacterial clearance were evaluated as markers for overall immune function following trauma-hemorrhage. Treatment with Srt1720 minimized the trauma-induced decreases in splenocyte proliferation (P < 0.05), whereas treatment with PGC1α siRNA led to diminished bacterial clearance. The PGC1α signaling pathway is an important regulator of mitochondrial function and biogenesis, which can potentially be harnessed to protect against hepatic injury and minimize the immunosuppression that is seen following trauma-hemorrhage.

Lipopolysaccaride induces autophagic signaling in macrophages via a TLR4, heme oxygenase-1 dependent pathway.

Toll-like receptor (TLR) signaling is an important part of the innate immune response. One of the downstream responses to TLR4 signaling upon lipopolysaccharide (LPS) stimulation is the induction of autophagy, which is a key response to multiple stressors. An additional adaptive signaling molecule that is involved in the response to stress is heme oxygenase-1 (HO-1). HO-1 signaling is essential to limit inflammation and restore homeostasis. We found that LPS induced autophagic signaling in macrophages via a TLR4, HO-1 dependent pathway in macrophages. These data add to the developing contribution of autophagic signaling as part of the inflammatory response.