Adverse Tracheal Intubation Events in Critically Ill Underweight and Obese Children: Retrospective Study of the National Emergency Airway for Children Registry (2013-2020).

OBJECTIVES: Extremes of patient body mass index are associated with difficult intubation and increased morbidity in adults. We aimed to determine the association between being underweight or obese with adverse airway outcomes, including adverse tracheal intubation (TI)-associated events (TIAEs) and/or severe peri-intubation hypoxemia (pulse oximetry oxygen saturation < 80%) in critically ill children. DESIGN/SETTING: Retrospective cohort using the National Emergency Airway for Children registry dataset of 2013-2020. PATIENTS: Critically ill children, 0 to 17 years old, undergoing TI in PICUs. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Registry data from 24,342 patients who underwent TI between 2013 and 2020 were analyzed. Patients were categorized using the Centers for Disease Control and Prevention weight-for-age chart: normal weight (5th-84th percentile) 57.1%, underweight (< 5th percentile) 27.5%, overweight (85th to < 95th percentile) 7.2%, and obese (≥ 95th percentile) 8.2%. Underweight was most common in infants (34%); obesity was most common in children older than 8 years old (15.1%). Underweight patients more often had oxygenation and ventilation failure (34.0%, 36.2%, respectively) as the indication for TI and a history of difficult airway (16.7%). Apneic oxygenation was used more often in overweight and obese patients (19.1%, 19.6%) than in underweight or normal weight patients (14.1%, 17.1%; p < 0.001). TIAEs and/or hypoxemia occurred more often in underweight (27.1%) and obese (24.3%) patients ( p < 0.001). TI in underweight children was associated with greater odds of adverse airway outcome compared with normal weight children after adjusting for potential confounders (underweight: adjusted odds ratio [aOR], 1.09; 95% CI, 1.01-1.18; p = 0.016). Both underweight and obesity were associated with hypoxemia after adjusting for covariates and site clustering (underweight: aOR, 1.11; 95% CI, 1.02-1.21; p = 0.01 and obesity: aOR, 1.22; 95% CI, 1.07-1.39; p = 0.002). CONCLUSIONS: In underweight and obese children compared with normal weight children, procedures around the timing of TI are associated with greater odds of adverse airway events.

Implementation of a Critical Care Asthma Pathway in the PICU.

OBJECTIVES: Acute asthma management has improved significantly across hospitals in the United States due to implementation of standardized care pathways. Management of severe acute asthma in ICUs is less well studied, and variations in management may delay escalation and/or deescalation of therapies and increase length of stay. In order to standardize the management of severe acute asthma in our PICU, a nurse- and respiratory therapist-driven critical care asthma pathway was designed, implemented, and tested. DESIGN: Cross-sectional study of severe acute asthma at baseline followed by implementation of a critical care asthma pathway. SETTING: Twenty-six-bed urban quaternary PICU within a children's hospital. PATIENTS: Patients 24 months to 18 years old admitted to the PICU in status asthmaticus. Patients with severe bacterial infections, chronic lung disease, heart disease, or immune disorders were excluded. INTERVENTIONS: Implementation of a nurse- and respiratory therapist-driven respiratory scoring tool and critical care asthma pathway with explicit escalation/deescalation instructions. MEASUREMENTS AND MAIN RESULTS: Primary outcome was PICU length of stay. Secondary outcomes were time to resolution of symptoms and hospital length of stay. Compliance approached 90% for respiratory score documentation and critical care asthma pathway adherence. Severity of illness at admission and clinical baseline characteristics were comparable in both groups. Pre intervention, the median ICU length of stay was 2 days (interquartile range, 1-3 d) with an overall hospital length of stay of 4 days (interquartile range, 3-6 d) (n = 74). After implementation of the critical care asthma pathway, the ICU length of stay was 1 day (interquartile range, 1-2 d) (p = 0.0013; n = 78) with an overall length of stay of 3 days (interquartile range, 2-3.75 d) (p < 0.001). The time to resolution of symptoms was reduced from a median of 66.5 hours in the preintervention group to 21 hours in the postintervention compliant group (p = 0.036). CONCLUSIONS: The use of a structured critical care asthma pathway, driven by an ICU nurse and respiratory therapist, is associated with faster resolution of symptoms, decreased ICU, and overall hospital lengths of stay in children admitted to an ICU for severe acute asthma.

Impact of Failure of Noninvasive Ventilation on the Safety of Pediatric Tracheal Intubation.

OBJECTIVES: Noninvasive ventilation is widely used to avoid tracheal intubation in critically ill children. The objective of this study was to assess whether noninvasive ventilation failure was associated with severe tracheal intubation-associated events and severe oxygen desaturation during tracheal intubation. DESIGN: Prospective multicenter cohort study of consecutive intubated patients using the National Emergency Airway Registry for Children registry. SETTING: Thirteen PICUs (in 12 institutions) in the United States and Canada. PATIENTS: All patients undergoing tracheal intubation in participating sites were included. Noninvasive ventilation failure group included children with any use of high-flow nasal cannula, continuous positive airway pressure, or bilevel noninvasive ventilation in the 6 hours prior to tracheal intubation. Primary tracheal intubation group included children without exposure to noninvasive ventilation within 6 hours before tracheal intubation. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Severe tracheal intubation-associated events (cardiac arrest, esophageal intubation with delayed recognition, emesis with aspiration, hypotension requiring intervention, laryngospasm, pneumothorax, pneumomediastinum) and severe oxygen desaturation (< 70%) were recorded prospectively. The study included 956 tracheal intubation encounters; 424 tracheal intubations (44%) occurred after noninvasive ventilation failure, with a median of 13 hours (interquartile range, 4-38 hr) of noninvasive ventilation. Noninvasive ventilation failure group included more infants (47% vs 33%; p < 0.001) and patients with a respiratory diagnosis (56% vs 30%; p < 0.001). Noninvasive ventilation failure was not associated with severe tracheal intubation-associated events (5% vs 5% without noninvasive ventilation; p = 0.96) but was associated with severe desaturation (15% vs 9% without noninvasive ventilation; p = 0.005). After controlling for baseline differences, noninvasive ventilation failure was not independently associated with severe tracheal intubation-associated events (p = 0.35) or severe desaturation (p = 0.08). In the noninvasive ventilation failure group, higher FIO2 before tracheal intubation (≥ 70%) was associated with severe tracheal intubation-associated events. CONCLUSIONS: Critically ill children are frequently exposed to noninvasive ventilation before intubation. Noninvasive ventilation failure was not independently associated with severe tracheal intubation-associated events or severe oxygen desaturation compared to primary tracheal intubation.

Protein biomarkers for incident deep venous thrombosis in critically ill adolescents: An exploratory study.

BACKGROUND: There are no tests to identify critically ill children at high risk of deep venous thrombosis (DVT). In this exploratory study, we aimed to identify proteins that are associated with incident DVT in critically ill adolescents. PROCEDURE: Plasma samples were obtained from critically ill adolescents within 24 hours after initiation of cardiopulmonary support. The adolescents were followed with ultrasound to detect the development of DVT of the lower extremity and clinically for bleeding. Thrombin-antithrombin complex and prothrombin fragment 1+2 were measured using immunosorbent assays, whereas procoagulation and anticoagulation factors were measured using multiplex assays. Plasma samples were also analyzed using SOMAscan, an aptamer-based capture assay. The associations between DVT and the log-transformed level of the proteins were assessed using logistic regression adjusting for the presence of femoral venous catheter and severity of illness. Associations were expressed as odds ratio (OR) for every log-fold increase in level of the protein with 95% confidence interval (CI). RESULTS: Plasma from 59 critically ill adolescents, of whom 9 developed incident DVT, was analyzed. The median age of the adolescents was 15.1 years (interquartile range, 14.0-16.7 years). Higher levels of thrombin-antithrombin complex (OR: 31.54; 95% CI: 2.09-475.92) and lower levels of factor XIII (OR: 0.03; 95% CI: 0.002-0.44) were associated with DVT. CD36, MIC-1, and EpoR were marginally associated with DVT. Only factor XIII was associated with clinically relevant bleeding (OR: 0.27; 95% CI: 0.08-0.97). CONCLUSIONS: We identified candidate protein biomarkers for incident DVT. We plan to validate our findings in adequately powered studies.

Epidemiology of Clinically Relevant Bleeding in Critically Ill Adolescents.

OBJECTIVES: The epidemiology of clinically relevant bleeding in critically ill adolescents, particularly those who are at high risk of venous thromboembolism, is unclear. In preparation for a randomized clinical trial of pharmacologic prophylaxis against venous thromboembolism, we characterized the epidemiology of clinically relevant bleeding in critically ill adolescents. DESIGN: Post hoc analysis of data from a pediatric multicenter observational study of venous thromboembolism. SETTING: Six PICUs. PATIENTS: Adolescents 13-17 years old who received cardiac or pulmonary support for at least 48 hours were eligible. Those admitted with venous thromboembolism or receiving therapeutic anticoagulation were excluded. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Adolescents (n = 88) were followed daily for the development of any bleeding event. The severity of the event was categorized based on the definitions by the International Society on Thrombosis and Haemostasis. The frequency of clinically relevant bleeding was 29.5% (95% CI, 20.3-40.2%) or 3.7 events (95% CI, 2.5-5.4 events) per 100 patient-days. Adolescents with venous thromboembolism were more likely to develop clinically relevant bleeding (hazard ratio, 2.06; 95% CI, 1.08-3.94). Age was negatively associated with clinically relevant bleeding (hazard ratio for every 1-year increase in age: 0.68; 95% CI, 0.58-0.79). In contrast, predicted risk of mortality (hazard ratio for every 0.10 increase in risk: 1.35; 95% CI, 1.05-1.74) and admission for trauma or surgery (hazard ratio: 2.04; 95% CI, 1.21-3.44) were positively associated with clinically relevant bleeding. The association of clinically relevant bleeding with medications, interventions, or laboratory tests, including mechanical ventilation and pharmacologic prophylaxis with anticoagulation, did not reach statistical significance. Adolescents with clinically relevant bleeding stayed in the hospital longer than those without clinically relevant bleeding. CONCLUSIONS: Clinically relevant bleeding is common in critically ill adolescents who are at high risk of venous thromboembolism. Admission for trauma or surgery can be used to stratify the risk of clinically relevant bleeding in these adolescents.

Epidemiology of Lower Extremity Deep Venous Thrombosis in Critically Ill Adolescents.

OBJECTIVE: To determine the epidemiology of lower extremity deep venous thrombosis (DVT) in critically ill adolescents, which currently is unclear. STUDY DESIGN: We performed a multicenter, prospective, cohort study. Adolescents aged 13-17 years who were admitted to 6 pediatric intensive care units and were anticipated to receive cardiopulmonary support for at least 48 hours were eligible, unless they were admitted with DVT or pulmonary embolism or were receiving or anticipated to receive therapeutic anticoagulation. While patients were in the unit, serial sonograms of the lower extremities were performed, then centrally adjudicated. Bayesian statistics were used to leverage the similarities between adults and adolescents. RESULTS: A total of 88 adolescents were enrolled, from whom 184 lower extremity sonograms were performed. Of these, 9 adolescents developed DVT, with 1 having bilateral DVT. The frequency of DVT was 12.4% (95% credible interval: 6.1%, 20.1%), which ranged from 6.3% to 19.8% with a variability of 41.0% across units. All cases of DVT occurred in adolescents who received invasive mechanical ventilation (frequency: 16.5%; 95% credible interval 8.1%, 26.6%). DVT was associated with femoral central venous catheterization (OR 15.44; 95% credible interval 1.62, 69.05) and severe illness (OR for every 0.1 increase in risk of mortality 3.11; 95% credible interval 1.19, 6.85). DVT appears to be associated with prolonged days on support. CONCLUSIONS: Our findings highlight the similarities and differences in the epidemiology of DVT between adults and adolescents. They support the conduct and inform the design of a trial of pharmacologic prophylaxis in critically ill adolescents.

Safety of tracheal intubation in the presence of cardiac disease in paediatric ICUs.

IntroductionChildren with CHD and acquired heart disease have unique, high-risk physiology. They may have a higher risk of adverse tracheal-intubation-associated events, as compared with children with non-cardiac disease.Materials and methodsWe sought to evaluate the occurrence of adverse tracheal-intubation-associated events in children with cardiac disease compared to children with non-cardiac disease. A retrospective analysis of tracheal intubations from 38 international paediatric ICUs was performed using the National Emergency Airway Registry for Children (NEAR4KIDS) quality improvement registry. The primary outcome was the occurrence of any tracheal-intubation-associated event. Secondary outcomes included the occurrence of severe tracheal-intubation-associated events, multiple intubation attempts, and oxygen desaturation. RESULTS: A total of 8851 intubations were reported between July, 2012 and March, 2016. Cardiac patients were younger, more likely to have haemodynamic instability, and less likely to have respiratory failure as an indication. The overall frequency of tracheal-intubation-associated events was not different (cardiac: 17% versus non-cardiac: 16%, p=0.13), nor was the rate of severe tracheal-intubation-associated events (cardiac: 7% versus non-cardiac: 6%, p=0.11). Tracheal-intubation-associated cardiac arrest occurred more often in cardiac patients (2.80 versus 1.28%; p<0.001), even after adjusting for patient and provider differences (adjusted odds ratio 1.79; p=0.03). Multiple intubation attempts occurred less often in cardiac patients (p=0.04), and oxygen desaturations occurred more often, even after excluding patients with cyanotic heart disease. CONCLUSIONS: The overall incidence of adverse tracheal-intubation-associated events in cardiac patients was not different from that in non-cardiac patients. However, the presence of a cardiac diagnosis was associated with a higher occurrence of both tracheal-intubation-associated cardiac arrest and oxygen desaturation.

Effect of Location on Tracheal Intubation Safety in Cardiac Disease-Are Cardiac ICUs Safer?

OBJECTIVES: Evaluate differences in tracheal intubation-associated events and process variances (i.e., multiple intubation attempts and oxygen desaturation) between pediatric cardiac ICUs and noncardiac PICUs in children with underlying cardiac disease. DESIGN: Retrospective cohort study using a multicenter tracheal intubation quality improvement database (National Emergency Airway Registry for Children). SETTING: Thirty-six PICUs (five cardiac ICUs, 31 noncardiac ICUs) from July 2012 to March 2016. PATIENTS: Children with medical or surgical cardiac disease who underwent intubation in an ICU. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Our primary outcome was the rate of any adverse tracheal intubation-associated event. Secondary outcomes were severe tracheal intubation-associated events, multiple tracheal intubation attempt rates, and oxygen desaturation. There were 1,502 tracheal intubations in children with underlying cardiac disease (751 in cardiac ICUs, 751 in noncardiac ICUs) reported. Cardiac ICUs and noncardiac ICUs had similar proportions of patients with surgical cardiac disease. Patients undergoing intubation in cardiac ICUs were younger (median age, 1 mo [interquartile range, 0-6 mo]) compared with noncardiac ICUs (median 3 mo [interquartile range, 1-11 mo]; p < 0.001). Tracheal intubation-associated event rates were not different between cardiac ICUs and noncardiac ICUs (16% vs 19%; adjusted odds ratio, 0.74; 95% CI, 0.54-1.02; p = 0.069). However, in a sensitivity analysis comparing cardiac ICUs with mixed ICUs (i.e., ICUs caring for children with either general pediatric or cardiac diseases), cardiac ICUs had decreased odds of adverse events (adjusted odds ratio, 0.71; 95% CI, 0.52-0.97; p = 0.033). Rates of severe tracheal intubation-associated events and multiple attempts were similar. Desaturations occurred more often during intubation in cardiac ICUs (adjusted odds ratio, 1.61; 95% CI, 1.04-1.15; p = 0.002). CONCLUSIONS: In children with underlying cardiac disease, rates of adverse tracheal intubation-associated events were not lower in cardiac ICUs as compared to noncardiac ICUs, even after adjusting for differences in patient characteristics and care models.

Frequency of Desaturation and Association With Hemodynamic Adverse Events During Tracheal Intubations in PICUs.

OBJECTIVES: Oxygen desaturation during tracheal intubation is known to be associated with adverse ICU outcomes in critically ill children. We aimed to determine the occurrence and severity of desaturation during tracheal intubations and the association with adverse hemodynamic tracheal intubation-associated events. DESIGN: Retrospective cohort study as a part of the National Emergency Airway Registry for Children Network's quality improvement project from January 2012 to December 2014. SETTING: International PICUs. PATIENTS: Critically ill children younger than 18 years undergoing primary tracheal intubations in the ICUs. INTERVENTIONS: tracheal intubation processes of care and outcomes were prospectively collected using standardized operational definitions. We defined moderate desaturation as oxygen saturation less than 80% and severe desaturation as oxygen saturation less than 70% during tracheal intubation procedures in children with initial oxygen saturation greater than 90% after preoxygenation. Adverse hemodynamic tracheal intubation-associated event was defined as cardiac arrests, hypo or hypertension requiring intervention, and dysrhythmia. MEASUREMENTS AND MAIN RESULTS: A total of 5,498 primary tracheal intubations from 31 ICUs were reported. Moderate desaturation was observed in 19.3% associated with adverse hemodynamic tracheal intubation-associated events (9.8% among children with moderate desaturation vs 4.4% without desaturation; p < 0.001). Severe desaturation was observed in 12.9% of tracheal intubations, also significantly associated with hemodynamic tracheal intubation-associated events. After adjusting for patient, provider, and practice factors, the occurrence of moderate desaturation was independently associated with hemodynamic tracheal intubation-associated events: adjusted odds ratio 1.83 (95% CI, 1.34-2.51; p < 0.001). The occurrence of severe desaturation was also independently associated with hemodynamic tracheal intubation-associated events: adjusted odds ratio 2.16 (95% CI, 1.54-3.04; p < 0.001). Number of tracheal intubation attempts was also significantly associated with the frequency of moderate and severe desaturations (p < 0.001). CONCLUSIONS: In this large tracheal intubation quality improvement database, we found moderate and severe desaturation are reported among 19% and 13% of all tracheal intubation encounters. Moderate and severe desaturations were independently associated with the occurrence of adverse hemodynamic events. Future quality improvement interventions may focus to reduce desaturation events.

Trend and Outcomes of Video Laryngoscope Use Across PICUs.

OBJECTIVE: Video (indirect) laryngoscopy is used as a primary tracheal intubation device for difficult airways in emergency departments and in adult ICUs. The use and outcomes of video laryngoscopy compared with direct laryngoscopy has not been quantified in PICUs or cardiac ICUs. DESIGN: Retrospective review of prospectively collected observational data from a multicenter tracheal intubation database (National Emergency Airway Registry for Children) from July 2010 to June 2015. SETTING: Thirty-six PICUs/cardiac ICUs across the United States, Canada, Japan, New Zealand, and Singapore. PATIENTS: Any patient admitted to a PICU or a pediatric cardiac ICU and undergoing tracheal intubation. INTERVENTIONS: Use of direct laryngoscopy versus video laryngoscopy for tracheal intubation. MEASUREMENTS AND MAIN RESULTS: There were 8,875 tracheal intubations reported in the National Emergency Airway Registry for Children database, including 7,947 (89.5%) tracheal intubations performed using direct laryngoscopy and 928 (10.5%) tracheal intubations performed using video laryngoscopy. Wide variability in video laryngoscopy use exists across PICUs (median, 2.6%; range, 0-55%). Video laryngoscopy was more often used in older children (p < 0.001), in children with history of a difficult airway (p = 0.01), in children intubated for ventilatory failure (p < 0.001), and to facilitate the completion of an elective procedure (p = 0.048). After adjusting for patient-level covariates, a secular trend, and site-level variance, the use of video laryngoscopy significantly increased over a 5-year period compared with fiscal year 2011 (odds ratio, 6.7; 95% CI, 1.7-26.8 for fiscal year 2014 and odds ratio, 11.2; 95% CI, 3.2-38.9 for fiscal year 2015). The use of video laryngoscopy was independently associated with a lower occurrence of tracheal intubation adverse events (adjusted odds ratio, 0.57; 95% CI, 0.42-0.77; p < 0.001) but not with a lower occurrence of severe tracheal intubation adverse events (adjusted odds ratio, 0.86; 95% CI, 0.56-1.32; p = 0.49) or fewer multiple attempts at endotracheal intubation (adjusted odds ratio, 0.93; 95% CI, 0.71-1.22; p = 0.59). CONCLUSIONS: Using National Emergency Airway Registry for Children data, we described patient-centered adverse outcomes associated with video laryngoscopy compared with direct laryngoscopy for tracheal intubation in the largest reported international cohort of children to date. Data from this study may be used to design sufficiently powered prospective studies comparing patient-centered outcomes for video laryngoscopy versus direct laryngoscopy during endotracheal intubation.

Relationship Between Adverse Tracheal Intubation Associated Events and PICU Outcomes.

OBJECTIVE: Tracheal intubation in PICUs is a common procedure often associated with adverse events. The aim of this study is to evaluate the association between immediate events such as tracheal intubation associated events or desaturation and ICU outcomes: length of stay, duration of mechanical ventilation, and mortality. STUDY DESIGN: Prospective cohort study with 35 PICUs using a multicenter tracheal intubation quality improvement database (National Emergency Airway Registry for Children: NEAR4KIDS) from January 2013 to June 2015. Desaturation defined as Spo2 less than 80%. SETTING: PICUs participating in NEAR4KIDS. PATIENTS: All patients less than18 years of age undergoing primary tracheal intubations with ICU outcome data were analyzed. MEASUREMENTS AND MAIN RESULTS: Five thousand five hundred four tracheal intubation encounters with median 108 (interquartile range, 58-229) tracheal intubations per site. At least one tracheal intubation associated event was reported in 892 (16%), with 364 (6.6%) severe tracheal intubation associated events. Infants had a higher frequency of tracheal intubation associated event or desaturation than older patients (48% infants vs 34% for 1-7 yr and 18% for 8-17 yr). In univariate analysis, the occurrence of tracheal intubation associated event or desaturation was associated with a longer mechanical ventilation (5 vs 3 d; p < 0.001) and longer PICU stay (14 vs 11 d; p < 0.001) but not with PICU mortality. The occurrence of severe tracheal intubation associated events was associated with longer mechanical ventilation (5 vs 4 d; p < 0.003), longer PICU stay (15 vs 12 d; p < 0.035), and PICU mortality (19.9% vs 9.6%; p < 0.0001). In multivariable analyses, the occurrence of tracheal intubation associated event or desaturation was significantly associated with longer mechanical ventilation (+12%; 95% CI, 4-21%; p = 0.004), and severe tracheal intubation associated events were independently associated with increased PICU mortality (OR = 1.80; 95% CI, 1.24-2.60; p = 0.002), after adjusted for patient confounders. CONCLUSIONS: Adverse tracheal intubation associated events and desaturations are common and associated with longer mechanical ventilation in critically ill children. Severe tracheal intubation associated events are associated with higher ICU mortality. Potential interventions to decrease tracheal intubation associated events and oxygen desaturation, such as tracheal intubation checklist, use of apneic oxygenation, and video laryngoscopy, may need to be considered to improve ICU outcomes.

Pulmonary Alveolar Proteinosis in Association with Secondary Hemophagocytic Lymphohistiocytosis.

Pulmonary alveolar proteinosis (PAP) is a rare diffuse lung disease in the pediatric population. There are currently few cases documenting hemophagocytic lymphohistiocytosis as a cause for secondary PAP. We describe an ex-preterm child with secondary hemophagocytic lymphohistiocytosis, complicated by PAP and hypoxemic respiratory failure.

Control of serum glucose concentration in critical illness.

PURPOSE OF REVIEW: Hyperglycemia is a significant problem for children in the ICU. Use of tight glycemic control (TGC) to manage hyperglycemia remains controversial, especially given the potential risk of insulin-induced hypoglycemia. This review will address the latest evidence regarding TGC in critically ill children. RECENT FINDINGS: Two randomized controlled trials (RCT) involving primarily postoperative cardiac surgery patients demonstrated the feasibility and safety of TGC in pediatric patients. The trials, however, had discrepant results with regards to the benefit of TGC. There is also uncertainty about the generalizability of these results to nonpostoperative cardiac patients. There is only one published study addressing the long-term safety of TGC in children. In this study, hypoglycemia was not associated with adverse effects on neurocognitive development. In contrast, articles from adult studies demonstrate increased risk of death with hypoglycemia. SUMMARY: Although the clinical benefit of TGC in critically ill children is still unclear, TGC can be done safely in this population.

Design, synthesis, and biological evaluation of novel cRGD-paclitaxel conjugates for integrin-assisted drug delivery.

The efficacy of taxane-based antitumor therapy is limited by several drawbacks which result in a poor therapeutic index. Thus, the development of approaches that favor selective delivery of taxane drugs (e.g., paclitaxel, PTX) to the disease area represents a truly challenging goal. On the basis of the strategic role of integrins in tumor cell survival and tumor progression, as well as on integrin expression in tumors, novel molecular conjugates were prepared where PTX is covalently attached to either cyclic AbaRGD (Azabicycloalkane-RGD) or AmproRGD (Aminoproline-RGD) integrin-recognizing matrices via structurally diverse connections. Receptor-binding assays indicated satisfactory-to-excellent α(V)ß(3) binding capabilities for most conjugates, while in vitro growth inhibition assays on a panel of human tumor cell lines revealed outstanding cell sensitivity values. Among the nine conjugate ensemble, derivative 21, bearing a robust triazole ring connected to ethylene glycol units by an amide function and showing excellent cell sensitivity properties, was selected for in vivo studies in an ovarian carcinoma model xenografted in immunodeficient mice. Remarkable antitumor activity was attained, superior to that of PTX itself, which was associated with a marked induction of aberrant mitoses, consistent with the mechanism of action of spindle poisons. Overall, the novel cRGD-PTX conjugates disclosed here represent promising candidates for further advancement in the domain of targeted antitumor therapy.

Synthesis of Gd and (68)Ga complexes in conjugation with a conformationally optimized RGD sequence as potential MRI and PET tumor-imaging probes.

We report the synthesis of novel chelates of Gd and (68)Ga with DPTA, DOTA, HP-DOA3, as well as with AAZTA, a novel chelating agent developed by our research group. These chelating agents were appropriately conjugated, prior to metal complexation, with DB58, an RGD peptidomimetic, conformationally constrained on an azabicycloalkane scaffold and endowed with high affinity for integrin α(ν)ß(3) . Because α(ν)ß(3) is involved in neo-angiogenesis in solid tumors and is also directly expressed in cancer cells (e.g. glioblastomas, melanomas) and ovarian, breast, and prostate cancers, these constructs could prove useful as molecular imaging probes in cancer diagnosis by MRI or PET techniques. Molecular modeling, integrin binding assays, and relaxivity assessments allowed the selection of compounds suitable for multiple expression on dendrimeric or nanoparticulate structures. These results also led us to an exploratory investigation of (68)Ga complexation for the promising (68)Ga-PET technique; the AAZTA complex 15((68)Ga) exhibited uptake in a xenograft model of glioblastoma, suggesting potentially useful developments with new probes with improved affinity.

Milk fat globule epidermal growth factor 8 attenuates acute lung injury in mice after intestinal ischemia and reperfusion.

RATIONALE: Milk fat globule epidermal growth factor 8 (MFG-E8) is a potent opsonin for the clearance of apoptotic cells and is produced by mononuclear cells of immune competent organs including the spleen and lungs. It attenuates chronic and acute inflammation such as autoimmune glomerulonephritis and bacterial sepsis by enhancing apoptotic cell clearance. Ischemia-reperfusion (I/R) injury of the gut results in severe inflammation, apoptosis, and remote organ damage, including acute lung injury (ALI). OBJECTIVES: To determine whether MFG-E8 attenuates intestinal and pulmonary inflammation after gut I/R. METHODS: Wild-type (WT) and MFG-E8(-/-) mice underwent superior mesenteric artery occlusion for 90 minutes, followed by reperfusion for 4 hours. A group of WT mice was treated with 0.4 microg/20 g recombinant murine MFG-E8 (rmMFG-E8) at the beginning of reperfusion. Four hours after reperfusion, MFG-E8, cytokines, myeloperoxidase activity, apoptosis, and histopathology were assessed. A 24-hour survival study was conducted in rmMFG-E8- and vehicle-treated WT mice. MEASUREMENTS AND MAIN RESULTS: Mesenteric I/R caused severe widespread injury and inflammation of the small intestines and remote organs, including the lungs. MFG-E8 levels decreased in the spleen and lungs by 50 to 60%, suggesting impaired apoptotic cell clearance. Treatment with rmMFG-E8 significantly suppressed inflammation (TNF-alpha, IL-6, IL-1beta, and myeloperoxidase) and injury of the lungs, liver, and kidneys. MFG-E8-deficient mice suffered from greatly increased inflammation and potentiated ALI, whereas treatment with rmMFG-E8 significantly improved the survival in WT mice. CONCLUSIONS: MFG-E8 attenuates inflammation and ALI after gut I/R and may represent a novel therapeutic agent.

Immature dendritic cell-derived exosomes rescue septic animals via milk fat globule epidermal growth factor-factor VIII [corrected].

Sepsis, a highly lethal systemic inflammatory syndrome, is associated with increases of proinflammatory cytokines (e.g., TNF-alpha, HMGB1) and the accumulation of apoptotic cells that have the potential to be detrimental. Depending on the timing and tissue, prevention of apoptosis in sepsis is beneficial; however, thwarting the development of secondary necrosis through the active removal of apoptotic cells by phagocytosis may offer a novel anti-sepsis therapy. Immature dendritic cells (IDCs) release exosomes that contain milk fat globule EGF factor VIII (MFGE8), a protein required to opsonize apoptotic cells for phagocytosis. In an experimental sepsis model using cecal ligation and puncture, we found that MFGE8 levels decreased in the spleen and blood, which was associated with impaired apoptotic cell clearance. Administration of IDC-derived exosomes promoted phagocytosis of apoptotic cells and significantly reduced mortality. Treatment with recombinant MFGE8 was equally protective, whereas MFGE8-deficient mice suffered from increased mortality. IDC exosomes also attenuated the release of proinflammatory cytokines in septic rats. Liberation of HMGB1, a nuclear protein that contributes to inflammation upon release from unengulfed apoptotic cells, was prevented by MFGE8-mediated phagocytosis in vitro. We conclude that IDC-derived exosomes attenuate the acute systemic inflammatory response in sepsis by enhancing apoptotic cell clearance via MFGE8.

VX-166: a novel potent small molecule caspase inhibitor as a potential therapy for sepsis.

INTRODUCTION: Prevention of lymphocyte apoptosis by caspase inhibition has been proposed as a novel treatment approach in sepsis. However, it has not been clearly demonstrated that caspase inhibitors improve survival in sepsis models when dosed post-insult. Also, there are concerns that caspase inhibitors might suppress the immune response. Here we characterize VX-166, a broad caspase inhibitor, as a novel potential treatment for sepsis. METHODS: VX-166 was studied in a number of enzymatic and cellular assays. The compound was then tested in a murine model of endotoxic shock (lipopolysaccharide (LPS), 20 mg/kg IV) and a 10 d rat model of polymicrobial sepsis by caecal ligation and puncture (CLP). RESULTS: VX-166 showed potent anti-apoptotic activity in vitro and inhibited the release of interleukin (IL)-1beta and IL-18. In the LPS model, VX-166 administered 0, 4, 8 and 12 h post-LPS significantly improved survival in a dose-dependent fashion (P < 0.0028). In the CLP model, VX-166 continuously administered by mini-osmotic pump significantly improved survival when dosed 3 h after insult, (40% to 92%, P = 0.009). When dosed 8 h post-CLP, VX-166 improved survival from 40% to 66% (P = 0.19). Mode of action studies in the CLP model confirmed that VX-166 significantly inhibited thymic atrophy and lymphocyte apoptosis as determined by flow cytometry (P < 0.01). VX-166 reduced plasma endotoxin levels (P < 0.05), suggesting an improved clearance of bacteria from the bloodstream. Release of IL-1beta in vivo or T-cell activation in vitro were moderately affected. CONCLUSIONS: Our studies enhance the case for the use of caspase inhibitors in sepsis. VX-166 itself has promise as a therapy for the treatment of sepsis in man.

Ghrelin hyporesponsiveness contributes to age-related hyperinflammation in septic shock.

OBJECTIVE: To test the hypothesis that hyporesponsiveness to ghrelin due to reduced growth hormone (GH) contributes to the aging-related hyperinflammatory state in sepsis. SUMMARY BACKGROUND DATA: Sepsis and septic shock are a serious problem, particularly in the geriatric population. Ghrelin is an endogenous ligand for the GH secretagogue receptor 1a (GHSR1a, ie, ghrelin receptor). The decline in GH with age is directly associated with many adverse changes that occur with aging. However, the role of GH, ghrelin, and GHSR1a in the age-associated vulnerability to sepsis remains unknown. METHODS: Male Fischer 344 rats (young: 3 months; aged: 24 months) were used. Plasma GH levels, ghrelin receptor expression, and neuronal activity in the parasympathostimulatory nuclei of the brain stem in normal young and aged animals were measured. Endotoxemia was induced by intravenous injection of lipopolysaccharide (LPS, 15 mg/kg BW). RESULTS: While LPS-induced release of proinflammatory cytokines from macrophages isolated from aged rats decreased, LPS injection resulted in an in vivo hyperinflammatory state. GH levels were lower in aged rats, which was associated with lower expression of GHSR1a in the dorsal vagal complex and a decrease in parasympathostimulatory neuronal activity. GHSR1a antagonist elevated LPS-induced cytokine release in young rats. GH increased GHSR-1a expression in the dorsal vagal complex in aged rats. Coadministration of ghrelin and GH, but not ghrelin alone or GH alone, markedly reduced cytokine levels and organ injury after endotoxemia in aged rats, which was associated with significantly elevated parasympathostimulatory neuronal activity. CONCLUSIONS: These findings suggest that the reduced central (brain) responsiveness to ghrelin due to the decreased GH, plays a major role in producing the hyperinflammatory state, resulting in severe organ injuries and high mortality after endotoxemia in aged animals. Ghrelin and GH can be developed as a novel therapy for sepsis in the geriatric population.