Glycolipid Metabolite ß-Glucosylceramide Is a Neutrophil Extracellular Trap-Inducing Ligand of Mincle Released during Bacterial Infection and Inflammation.

Neutrophil extracellular traps (NETs) are implicated in host defense and inflammatory pathologies alike. A wide range of pathogen- and host-derived factors are known to induce NETs, yet the knowledge about specific receptor-ligand interactions in this response is limited. We previously reported that macrophage-inducible C-type lectin (Mincle) regulates NET formation. In this article, we identify glycosphingolipid ß-glucosylceramide (ß-GlcCer) as a specific NET-inducing ligand of Mincle. We found that purified ß-GlcCer induced NETs in mouse primary neutrophils in vitro and in vivo, and this effect was abrogated in Mincle deficiency. Cell-free ß-GlcCer accumulated in the lungs of pneumonic mice, which correlated with pulmonary NET formation in wild-type, but not in Mincle-/-, mice infected intranasally with Klebsiella pneumoniae Although leukocyte infiltration by ß-GlcCer administration in vivo did not require Mincle, NETs induced by this sphingolipid were important for bacterial clearance during Klebsiella infection. Mechanistically, ß-GlcCer did not activate reactive oxygen species formation in neutrophils but required autophagy and glycolysis for NET formation, because ATG4 inhibitor NSC185058, as well as glycolysis inhibitor 2-deoxy-d-glucose, abrogated ß-GlcCer-induced NETs. Forced autophagy activation by tamoxifen could overcome the inhibitory effect of glycolysis blockage on ß-GlcCer-mediated NET formation, suggesting that autophagy activation is sufficient to induce NETs in response to this metabolite in the absence of glycolysis. Finally, ß-GlcCer accumulated in the plasma of patients with systemic inflammatory response syndrome, and its levels correlated with the extent of systemic NET formation in these patients. Overall, our results posit ß-GlcCer as a potent NET-inducing ligand of Mincle with diagnostic and therapeutic potential in inflammatory disease settings.

M1 Macrophage Polarization Is Dependent on TRPC1-Mediated Calcium Entry.

Macrophage plasticity is essential for innate immunity, but in-depth signaling mechanism(s) regulating their functional phenotypes are ill-defined. Here we report that interferon (IFN) γ priming of naive macrophages induces store-mediated Ca2+ entry and inhibition of Ca2+ entry impairs polarization to M1 inflammatory phenotype. In vitro and in vivo functional analyses revealed ORAI1 to be a primary contributor to basal Ca2+ influx in macrophages, whereas IFNγ-induced Ca2+ influx was mediated by TRPC1. Deficiency of TRPC1 displayed abrogated IFNγ-induced M1 inflammatory mediators in macrophages. In a preclinical model of peritonitis by Klebsiella pneumoniae infection, macrophages showed increased Ca2+ influx, which was TRPC1 dependent. Macrophages from infected TRPC1-/- mice showed inhibited expression of M1-associated signature molecules. Furthermore, in human patients with systemic inflammatory response syndrome, the level of TRPC1 expression in circulating macrophages directly correlated with M1 inflammatory mediators. Overall, TRPC1-mediated Ca2+ influx is essential for the induction/shaping of macrophage polarization to M1 inflammatory phenotype.

Ten-year retrospective study of delayed diagnosis of injury in pediatric trauma patients at a level II trauma center.

BACKGROUND: Published rates of delayed diagnosis of injury (DDI) in pediatric trauma vary from 1.0% to 18%. The purpose of this study was to determine the long-term trend of DDI over 10 years, to identify risk factors associated with DDI, and to elucidate patterns of DDI. METHODS: All patients aged 14 and younger who were admitted to Parkview Hospital for major trauma between January 1, 1997 and December 31, 2006 were included (1100 patients). Data were collected from a trauma registry that is maintained of all trauma admissions. RESULTS: A total of 47 delayed diagnoses of injury were found in 44 patients for a rate of 4.0%. Patients with a DDI were more likely to have been intubated in the emergency department, transported by air, have an Injury Severity Score greater than 15, and have a Glasgow Coma Scale below 8 (P < 0.05). Mean intensive care unit and overall length of stay was longer in the DDI group. Missed injuries resulted in a change in therapy in 80% of cases. There were 5 missed intra-abdominal injuries, 4 of which required surgery. Three injuries were discovered upon outpatient follow-up. There was a trend for more missed upper extremity injuries in older patients and missed lower extremity injuries in younger patients. CONCLUSIONS: The rate of missed injuries remained relatively constant over the past 10 years at our institution. More severely injured patients are more likely to have missed injuries. Special attention to the lower extremities of the younger trauma patient may be warranted.

Discharging to a nursing home: not a terminal event--a follow-up study of senior motor vehicle crash patients.

Discharge to a nursing home (NH) because of chronic debilitating diseases or old age is generally a terminal event. The purpose of this study was to evaluate the NH outcome of senior citizens injured in motor vehicle crashes (MVC) discharged to a NH. From 2000 through 2004, 157 patients 75 years and older were admitted to the hospital for MVC. Of these, 32 patients were discharged to a NH, and these patients or their proxies were interviewed by telephone in June 2005 to request information as to driving status before and after the MVC, feeding, expression, and locomotion status, and/or date of death. After discharged from the NH, 72 per cent (23/32) of the patients lived at home, 52.2 per cent (12/23) among the drivers returned to drive, and those with functional impairments (excluding the five NH deaths and four still remaining in a NH) at the time of hospital discharge had 100 per cent or partial improvement in three functional independent measures at the time of the interview: 5 cases in feeding, 2 in expression, and 20 in locomotion. Eleven of the 20 individuals dependent or partially dependent in locomotion status were fully independent. The majority of the senior patients discharged to a NH after a MVC returned to a normal life by going back home, driving again, and regaining functional activities after NH discharge. Discharge to a NH for elderly MVC trauma patients may be regarded as a stepping-stone to independent living rather than a final resting place.

Pediatric trauma deaths: a three-part analysis from a nonacademic trauma center.

A three-part analysis was undertaken to assess pediatric trauma mortality in a nonacademic Level II trauma center at Parkview Hospital in Fort Wayne, Indiana. Part I was a comparison of Parkview trauma registry data collected from 1999 through 2003 with those of pediatric and adult trauma centers in Pennsylvania. The same methodology used in Pennsylvania was used for the initial evaluation of pediatric deaths from trauma in our trauma center. Part II was a formal in-depth analysis of all individual pediatric deaths as well as surgical cases with head, spleen, and liver injuries from the same time frame. Part III proposes a new methodology to calculate a risk-adjusted mortality rate based on the TRISS model for the evaluation of a trauma system. The use of specific mortality and surgical intervention rates was not an accurate reflection of trauma center outcome. The proposed risk-adjusted mortality rate calculation is perhaps an effective outcome measure to assess patient care in a trauma system.

Amish buggy injuries in the 21st century: A retrospective review from a rural level II trauma center.

Horse-drawn buggies are rarely used in modern society except among certain religious groups. Northeastern Indiana has one of the largest populations of one such group: the Amish. Although there are papers written about the incidence of buggy crashes, no paper has specifically addressed the specific types of injuries sustained when buggies collide with motorized vehicles. This paper reviews the types of injuries sustained when such events occur.