Sphingosine Prevents Rhinoviral Infections.

Rhinoviral infections cause approximately 50% of upper respiratory tract infections and novel treatment options are urgently required. We tested the effects of 10 µM to 20 µM sphingosine on the infection of cultured and freshly isolated human cells with minor and major group rhinovirus in vitro. We also performed in vivo studies on mice that were treated with an intranasal application of 10 µL of either a 10 µM or a 100 µM sphingosine prior and after infection with rhinovirus strains 1 and 2 and determined the infection of nasal epithelial cells in the presence or absence of sphingosine. Finally, we determined and characterized a direct binding of sphingosine to rhinovirus. Our data show that treating freshly isolated human nasal epithelial cells with sphingosine prevents infections with rhinovirus strains 2 (minor group) and 14 (major group). Nasal infection of mice with rhinovirus 1b and 2 is prevented by the intranasal application of sphingosine before or as long as 8 h after infection with rhinovirus. Nasal application of the same doses of sphingosine exerts no adverse effects on epithelial cells as determined by hemalaun and TUNEL stainings. The solvent, octylglucopyranoside, was without any effect in vitro and in vivo. Mechanistically, we demonstrate that the positively charged lipid sphingosine binds to negatively charged molecules in the virus, which seems to prevent the infection of epithelial cells. These findings indicate that exogenous sphingosine prevents infections with rhinoviruses, a finding that could be therapeutically exploited. In addition, we demonstrated that sphingosine has no obvious adverse effects on the nasal mucosa. Sphingosine prevents rhinoviral infections by a biophysical mode of action, suggesting that sphingosine could serve to prevent many viral infections of airways and epithelial cells in general. Future studies need to determine the molecular mechanisms of how sphingosine prevents rhinoviral infections and whether sphingosine also prevents infections with other viruses inducing respiratory tract infections. Furthermore, our studies do not provide detailed pharmacokinetics that are definitely required before the further development of sphingosine.

Are the non-weight bearing guidelines for the after treatment of calcaneal fractures still decisive? A Dutch survey among orthopaedic and trauma surgeons.

PURPOSE: The current rehabilitation for patients with surgically treated displaced intra-articular calcaneal fractures (DIACFs) consists of non-weightbearing for 8-12 weeks. The purpose of the present survey was to investigate the current pre-, peri- and post-operative practices among Dutch foot and ankle surgeons. Moreover, it aims to analyze whether surgeons comply to the Arbeitsgemeinschaft für Osteosynthesefragen (AO) guidelines and which decision criteria were used in the determination of the start of weightbearing. METHODS: A survey was distributed among Dutch trauma and orthopaedic surgeons to determine the most common practices in postoperative weightbearing in patients with DIACFs. RESULTS: 75 surgeons responded to the survey. 33% of the respondents adhered to the AO guidelines. 4% of the respondents strictly followed non-weightbearing guidelines, while 96% interpret the AO guidelines or their local protocol freely, in any frequency. When respondents tended to deviate from the AO guidelines or local protocol, a good patients' compliance to therapy was expected. 83% of the respondents started weightbearing on the fracture, based on reported patient complaints. 87% of the respondents did not see any relation between early weightbearing and the occurrence of complications, including loosening of osteosynthesis materials. CONCLUSION: This study demonstrates that there is limited consensus on the rehabilitation for DIACFs. Moreover, it shows that most surgeons are inclined to interpret the current (AO) guideline or their own local protocol freely. New guidelines, supported with well-founded literature, could help surgeons in a more appropriate daily practice in weightbearing for the rehabilitation of calcaneal fractures.

Ceramide levels in blood plasma correlate with major depressive disorder severity and its neutralization abrogates depressive behavior in mice.

Major depressive disorder (MDD) is a severe disease of unknown pathogenesis that will affect ∼10% of people during their lifetime. Therapy for MDD requires prolonged treatment and often fails, predicating a need for novel treatment strategies. Here, we report increased ceramide levels in the blood plasma of MDD patients and in murine stress-induced models of MDD. These blood plasma ceramide levels correlated with the severity of MDD in human patients and were independent of age, sex, or body mass index. In addition, intravenous injection of anti-ceramide antibodies or neutral ceramidase rapidly abrogated stress-induced MDD, and intravenous injection of blood plasma from mice with MDD induced depression-like behavior in untreated mice, which was abrogated by ex vivo preincubation of the plasma with anti-ceramide antibodies or ceramidase. Mechanistically, we demonstrate that ceramide accumulated in endothelial cells of the hippocampus of stressed mice, evidenced by the quantitative measurement of ceramide in purified hippocampus endothelial cells. We found ceramide inhibited the activity of phospholipase D (PLD) in endothelial cells in vitro and in the hippocampus in vivo and thereby decreased phosphatidic acid in the hippocampus. Finally, we show intravenous injection of PLD or phosphatidic acid abrogated MDD, indicating the significance of this pathway in MDD pathogenesis. Our data indicate that ceramide controls PLD activity and phosphatidic acid formation in hippocampal endothelial cells and thereby mediates MDD. We propose that neutralization of plasma ceramide could represent a rapid-acting targeted treatment for MDD.

Role of Tyrosine Nitrosylation in Stress-Induced Major Depressive Disorder: Mechanisms and Implications.

Major depressive disorder (MDD) has a lifetime prevalence of approximately 10% and is one of the most common diseases worldwide. Although many pathogenetic mechanisms of MDD have been proposed, molecular details and a unifying hypothesis of the pathogenesis of MDD remain to be defined. Here, we investigated whether tyrosine nitrosylation, which is caused by reaction of the C-atom 3 of the tyrosine phenol ring with peroxynitrate (ONOO-), plays a role in experimental MDD, because tyrosine nitrosylation may affect many cell functions altered in MDD. To this end, we induced stress through glucocorticoid application or chronic environmental unpredictable stress and determined tyrosine nitrosylation in the hippocampus through immuno-staining and ELISA. The role of catalases and peroxidases for tyrosine nitrosylation was measured using enzyme assays. We show that glucocorticoid- and chronic unpredictable environmental stress induced tyrosine nitrosylation in the hippocampus. Long-term treatment of stressed mice with the classical antidepressants amitriptyline or fluoxetine prevented tyrosine nitrosylation. Tyrosine nitrosylation was also prevented through i.v. application of anti-ceramide antibodies or recombinant ceramidase to neutralize or degrade, respectively, blood plasma ceramide that has been recently shown to induce experimental MDD. Finally, the application of phosphatidic acid, previously shown to be reduced in the hippocampus upon stress, also reverted stress-induced tyrosine nitrosylation. The inhibition of tyrosine nitrosylation by interfering with the formation of NO radicals at least partly restored normal behavior in stressed mice. These data suggest that tyrosine nitrosylation might contribute to the pathogenesis of MDD and targeting this process might contribute to the treatment of MDD.

Inhibition of acid sphingomyelinase by ambroxol prevents SARS-CoV-2 entry into epithelial cells.

The acid sphingomyelinase/ceramide system has been shown to be important for cellular infection with at least some viruses, for instance, rhinovirus or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Functional inhibition of the acid sphingomyelinase using tricyclic antidepressants prevented infection of epithelial cells, for instance with SARS-CoV-2. The structure of ambroxol, that is, trans-4-[(2,4-dibromanilin-6-yl)-methyamino]-cyclohexanol, a mucolytic drug applied by inhalation, suggests that the drug might inhibit the acid sphingomyelinase and thereby infection with SARS-CoV-2. To test this, we used vesicular stomatitis virus pseudoviral particles presenting SARS-CoV-2 spike protein on their surface (pp-VSV-SARS-CoV-2 spike), a bona fide system for mimicking SARS-CoV-2 entry into cells. Viral uptake and formation of ceramide localization were determined by fluorescence microscopy, activity of the acid sphingomyelinase by consumption of [14C]sphingomyelin and ceramide was quantified by a kinase method. We found that entry of pp-VSV-SARS-CoV-2 spike required activation of acid sphingomyelinase and release of ceramide, events that were all prevented by pretreatment with ambroxol. We also obtained nasal epithelial cells from human volunteers prior to and after inhalation of ambroxol. Inhalation of ambroxol reduced acid sphingomyelinase activity in nasal epithelial cells and prevented pp-VSV-SARS-CoV-2 spike-induced acid sphingomyelinase activation, ceramide release, and entry of pp-VSV-SARS-CoV-2 spike ex vivo. The addition of purified acid sphingomyelinase or C16 ceramide restored entry of pp-VSV-SARS-CoV-2 spike into ambroxol-treated epithelial cells. We propose that ambroxol might be suitable for clinical studies to prevent coronavirus disease 2019.

Interferon regulatory factor 8 regulates expression of acid ceramidase and infection susceptibility in cystic fibrosis.

Most patients with cystic fibrosis (CF) suffer from acute and chronic pulmonary infections with bacterial pathogens, which often determine their life quality and expectancy. Previous studies have demonstrated a downregulation of the acid ceramidase in CF epithelial cells resulting in an increase of ceramide and a decrease of sphingosine. Sphingosine kills many bacterial pathogens, and the downregulation of sphingosine seems to determine the infection susceptibility of cystic fibrosis mice and patients. It is presently unknown how deficiency of the cystic fibrosis transmembrane conductance regulator (CFTR) connects to a marked downregulation of the acid ceramidase in human and murine CF epithelial cells. Here, we employed quantitative PCR, western blot analysis, and enzyme activity measurements to study the role of IRF8 for acid ceramidase regulation. We report that genetic deficiency or functional inhibition of CFTR/Cftr results in an upregulation of interferon regulatory factor 8 (IRF8) and a concomitant downregulation of acid ceramidase expression with CF and an increase of ceramide and a reduction of sphingosine levels in tracheal and bronchial epithelial cells from both human individuals or mice. CRISPR/Cas9- or siRNA-mediated downregulation of IRF8 prevented changes of acid ceramidase, ceramide, and sphingosine in CF epithelial cells and restored resistance to Pseudomonas aeruginosa infections, which is one of the most important and common pathogens in lung infection of patients with CF. These studies indicate that CFTR deficiency causes a downregulation of acid ceramidase via upregulation of IRF8, which is a central pathway to control infection susceptibility of CF cells.

Molecular targets of endothelial phosphatidic acid regulating major depressive disorder.

Major depressive disorder (MDD) is a severe disease of unknown pathogenesis with a lifetime prevalence of ~10%. Therapy requires prolonged treatment that often fails. We have previously demonstrated that ceramide levels in the blood plasma of patients and in mice with experimental MDD are increased. Neutralization of blood plasma ceramide prevented experimental MDD in mice. Mechanistically, we demonstrated that blood plasma ceramide accumulated in endothelial cells of the hippocampus, inhibited phospholipase D (PLD) and thereby decreased phosphatidic acid in the hippocampus. Here, we demonstrate that phosphatidic acid binds to and controls the activity of phosphotyrosine phosphatase (PTP1B) in the hippocampus and thus determines tyrosine phosphorylation of a variety of cellular proteins including TrkB. Injection of PLD, phosphatidic acid, or inhibition of PTP1B abrogated MDD and normalized cellular tyrosine phosphorylation, including phosphorylation of TrkB and neurogenesis in the hippocampus. Most importantly, these treatments also rapidly normalized behavior of mice with experimental MDD. Since phosphatidic acid binds to and inhibits PTP1B, the lack of phosphatidic acid results in increased activity of PTP1B and thereby in reduced tyrosine phosphorylation of TrkB and other cellular proteins. Thus, our data indicate a novel pathogenetic mechanism of and a rapidly acting targeted treatment for MDD.

The Detrimental Impact of the COVID-19 Pandemic on Major Trauma Outcomes in the Netherlands: A Comprehensive Nationwide Study.

OBJECTIVE: To evaluate the impact of the COVID-19 pandemic on the outcome of major trauma patients in the Netherlands. SUMMARY BACKGROUND DATA: Major trauma patients highly rely on immediate access to specialized services, including ICUs, shortages caused by the impact of the COVID-19 pandemic may influence their outcome. METHODS: A multi-center observational cohort study, based on the Dutch National Trauma Registry was performed. Characteristics, resource usage, and outcome of major trauma patients (injury severity score ≥16) treated at all trauma-receiving hospitals during the first COVID-19 peak (March 23 through May 10) were compared with those treated from the same period in 2018 and 2019 (reference period). RESULTS: During the peak period, 520 major trauma patients were admitted, versus 570 on average in the pre-COVID-19 years. Significantly fewer patients were admitted to ICU facilities during the peak than during the reference period (49.6% vs 55.8%; P=0.016). Patients with less severe traumatic brain injuries in particular were less often admitted to the ICU during the peak (40.5% vs 52.5%; P=0.005). Moreover, this subgroup showed an increased mortality compared to the reference period (13.5% vs 7.7%; P=0.044). These results were confirmed using multivariable logistic regression analyses. In addition, a significant increase in observed versus predicted mortality was recorded for patients who had a priori predicted mortality of 50% to 75% (P=0.012). CONCLUSIONS: The COVID-19 peak had an adverse effect on trauma care as major trauma patients were less often admitted to ICU and specifically those with minor through moderate brain injury had higher mortality rates.

Are 3D-printed Models of Tibial Plateau Fractures a Useful Addition to Understanding Fractures for Junior Surgeons?

BACKGROUND: Tibial plateau fractures are often complex, and they can be challenging to treat. Classifying fractures is often part of the treatment process, but intra- and interobserver reliability of fracture classification systems often is inadequate to the task, and classifications that lack reliability can mislead providers and result in harm to patients. Three-dimensionally (3D)-printed models might help in this regard, but whether that is the case for the classification of tibial plateau fractures, and whether the utility of such models might vary by the experience of the individual classifying the fractures, is unknown. QUESTIONS/PURPOSES: (1) Does the overall interobserver agreement improve when fractures are classified with 3D-printed models compared with conventional radiology? (2) Does interobserver agreement vary among attending and consultant trauma surgeons, senior surgical residents, and junior surgical residents? (3) Do surgeons' and surgical residents' confidence and accuracy improve when tibial plateau fractures are classified with an additional 3D model compared with conventional radiology? METHODS: Between 2012 and 2020, 113 patients with tibial plateau fractures were treated at a Level 1 trauma center. Forty-four patients were excluded based on the presence of bone diseases (such as osteoporosis) and the absence of a CT scan. To increase the chance to detect an improvement or deterioration and to prevent observers from losing focus during the classification, we decided to include 40 patients with tibial plateau fractures. Nine trauma surgeons, eight senior surgical residents, and eight junior surgical residents-none of whom underwent any study-specific pretraining-classified these fractures according to three often-used classification systems (Schatzker, OA/OTA, and the Luo three-column concept), with and without 3D-printed models, and they indicated their overall confidence on a 10-point Likert scale, with 0 meaning not confident at all and 10 absolutely certainty. To set the gold standard, a panel of three experienced trauma surgeons who had special expertise in knee surgery and 10 years to 25 years of experience in practice also classified the fractures until consensus was reached. The Fleiss kappa was used to determine interobserver agreement for fracture classification. Differences in confidence in assessing fractures with and without the 3D-printed model were compared using a paired t-test. Accuracy was calculated by comparing the participants' observations with the gold standard. RESULTS: The overall interobserver agreement improved minimally for fracture classification according to two of three classification systems (Schatzker: κconv = 0.514 versus κ3Dprint = 0.539; p = 0.005; AO/OTA:κconv = 0.359 versus κ3Dprint = 0.372; p = 0.03). However, none of the classification systems, even when used by our most experienced group of trauma surgeons, achieved more than moderate interobserver agreement, meaning that a large proportion of fractures were misclassified by at least one observer. Overall, there was no improvement in self-assessed confidence in classifying fractures or accuracy with 3D-printed models; confidence was high (about 7 points on a 10-point scale) as rated by all observers, despite moderate or worse accuracy and interobserver agreement. CONCLUSION: Although 3D-printed models minimally improved the overall interobserver agreement for two of three classification systems, none of the classification systems achieved more than moderate interobserver agreement. This suggests that even with 3D-printed models, many fractures would be misclassified, which could result in misleading communication, inaccurate prognostic assessments, unclear research, and incorrect treatment choices. Therefore, we cannot recommend the use of 3D-printed models in practice and research for classification of tibial plateau fractures. LEVEL OF EVIDENCE: Level III, diagnostic study.

Prevalence of inflicted and neglectful femur shaft fractures in young children in national level I trauma centers.

BACKGROUND: The prevalence of inflicted femur fractures in young children varies (1.5-35.2%), but these data are based on small retrospective studies with high heterogeneity. Age and mobility of the child seem to be indicators of inflicted trauma. OBJECTIVE: This study describes other factors associated with inflicted and neglectful trauma that can be used to distinguish inflicted and neglectful from accidental femur fractures. MATERIALS AND METHODS: This retrospective study included children (0-6 years) who presented with an isolated femur fracture at 1 of the 11 level I trauma centers in the Netherlands between January 2010 and January 2016. Outcomes were classified based on the conclusions of the Child Abuse and Neglect teams or the court. Cases in which conclusions were unavailable and there was no clear accidental cause were reviewed by an expert panel. RESULTS: The study included 328 children; 295 (89.9%) cases were classified as accidental trauma. Inflicted trauma was found in 14 (4.3%), while 19 (5.8%) were cases of neglect. Indicators of inflicted trauma were age 0-5 months (29%, positive likelihood ratio [LR +] 8.35), 6-12 months (18%, LR + 5.98) and 18-23 months (14%, LR + 3.74). Indicators of neglect were age 6-11 months (18%, LR + 4.41) and age 18-23 months (8%, LR + 1.65). There was no difference in fracture morphology among groups. CONCLUSION: It is unlikely that an isolated femur fracture in ambulatory children age > 24 months is caused by inflicted trauma/neglect. Caution is advised in children younger than 24 months because that age is the main factor associated with inflicted trauma/neglect and inflicted femur fractures.

Sphingosine kills bacteria by binding to cardiolipin.

Sphingosine is a long-chain sphingoid base that has been shown to have bactericidal activity against many pathogens, including Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli We have previously demonstrated that sphingosine is present in nasal, tracheal, and bronchial epithelial cells and constitutes a central element of the defense of the airways against bacterial pathogens. Here, using assorted lipid-binding and cell biology assays, we demonstrate that exposing P. aeruginosa and S. aureus cells to sphingosine results in a very rapid, i.e. within minutes, permeabilization of the bacterial plasma membrane, resulting in leakiness of the bacterial cells, loss of ATP, and loss of bacterial metabolic activity. These alterations rapidly induced bacterial death. Mechanistically, we demonstrate that the presence of the protonated NH2 group in sphingosine, which is an amino-alcohol, is required for sphingosine's bactericidal activity. We also show that the protonated NH2 group of sphingosine binds to the highly negatively-charged lipid cardiolipin in bacterial plasma membranes. Of note, this binding was required for bacterial killing by sphingosine, as revealed by genetic experiments indicating that E. coli or P. aeruginosa strains that lack cardiolipin synthase are resistant to sphingosine, both in vitro and in vivo We propose that binding of sphingosine to cardiolipin clusters cardiolipin molecules in the plasma membrane of bacteria. This clustering results in the formation of gel-like or even crystal-like structures in the bacterial plasma membrane and thereby promotes rapid permeabilization of the plasma membrane and bacterial cell death.

Sphingosine prevents binding of SARS-CoV-2 spike to its cellular receptor ACE2.

Sphingosine has been shown to prevent and eliminate bacterial infections of the respiratory tract, but it is unknown whether sphingosine can be also employed to prevent viral infections. To test this hypothesis, we analyzed whether sphingosine regulates the infection of cultured and freshly isolated ex vivo human epithelial cells with pseudoviral particles expressing SARS-CoV-2 spike (pp-VSV-SARS-CoV-2 spike) that served as a bona fide system mimicking SARS-CoV-2 infection. We demonstrate that exogenously applied sphingosine suspended in 0.9% NaCl prevents cellular infection with pp-SARS-CoV-2 spike. Pretreatment of cultured Vero epithelial cells or freshly isolated human nasal epithelial cells with low concentrations of sphingosine prevented adhesion of and infection with pp-VSV-SARS-CoV-2 spike. Mechanistically, we demonstrate that sphingosine binds to ACE2, the cellular receptor of SARS-CoV-2, and prevents the interaction of the receptor-binding domain of the viral spike protein with ACE2. These data indicate that sphingosine prevents at least some viral infections by interfering with the interaction of the virus with its receptor. Our data also suggest that further preclinical and finally clinical examination of sphingosine is warranted for potential use as a prophylactic or early treatment for coronavirus disease-19.

Acid Ceramidase Rescues Cystic Fibrosis Mice from Pulmonary Infections.

Previous studies have shown that sphingosine kills a variety of pathogenic bacteria, including Pseudomonas aeruginosa and Staphylococcus aureus Sphingosine concentrations are decreased in airway epithelial cells of cystic fibrosis (CF) mice, and this defect has been linked to the infection susceptibility of these mice. Here, we tested whether the genetic overexpression of acid ceramidase rescues cystic fibrosis mice from pulmonary infections with P. aeruginosa We demonstrate that the transgenic overexpression of acid ceramidase in CF mice corresponds to the overexpression of acid ceramidase in bronchial and tracheal epithelial cells and normalizes ceramide and sphingosine levels in bronchial and tracheal epithelial cells. In addition, the expression of ß1-integrin, which is ectopically expressed on the luminal surface of airway epithelial cells in cystic fibrosis mice, an alteration that is very important for mediating pulmonary P. aeruginosa infections in cystic fibrosis, is normalized in cystic fibrosis airways upon the overexpression of acid ceramidase. Most importantly, the overexpression of acid ceramidase protects cystic fibrosis mice from pulmonary P. aeruginosa infections. Infection of CF mice or CF mice that inhaled sphingosine with P. aeruginosa or a P. aeruginosa mutant that is resistant to sphingosine indicates that sphingosine and not a metabolite kills P. aeruginosa upon pulmonary infection. These studies further support the use of acid ceramidase and its metabolite sphingosine as potential treatments of cystic fibrosis.

Antimicrobial Coating Prevents Ventilator-Associated Pneumonia in a 72 hour Large Animal Model.

BACKGROUND: The primary goal of this study was to demonstrate that endotracheal tubes coated with antimicrobial lipids plus mucolytic or antimicrobial lipids with antibiotics plus mucolytic would significantly reduce pneumonia in the lungs of pigs after 72 hours of continuous mechanical ventilation compared to uncoated controls. MATERIALS AND METHODS: Eighteen female pigs were mechanically ventilated for up to 72 hours through uncoated endotracheal tubes, endotracheal tubes coated with the antimicrobial lipid, octadecylamine, and the mucolytic, N-acetylcysteine, or tubes coated with octadecylamine, N-acetylcysteine, doxycycline, and levofloxacin (6 pigs per group). No exogenous bacteria were inoculated into the pigs, pneumonia resulted from the pigs' endogenous oral flora. Vital signs were recorded every 15 minutes and arterial blood gas measurements were obtained for the duration of the experiment. Pigs were sacrificed either after completion of 72 hours of mechanical ventilation or just prior to hypoxic arrest. Lungs, trachea, and endotracheal tubes were harvested for analysis to include bacterial counts of lung, trachea, and endotracheal tubes, lung wet and dry weights, and lung tissue for histology. RESULTS: Pigs ventilated with coated endotracheal tubes were less hypoxic, had less bacterial colonization of the lungs, and survived significantly longer than pigs ventilated with uncoated tubes. Octadecylamine-N-acetylcysteine-doxycycline-levofloxacin coated endotracheal tubes had less bacterial colonization than uncoated or octadecylamine-N-acetylcysteine coated tubes. CONCLUSION: Endotracheal tubes coated with antimicrobial lipids plus mucolytic and antimicrobial lipids with antibiotics plus mucolytic reduced bacterial colonization of pig lungs after prolonged mechanical ventilation and may be an effective strategy to reduce ventilator-associated pneumonia.

The Role of Acid Sphingomyelinase Inhibition in Repetitive Mild Traumatic Brain Injury.

BACKGROUND: Chronic traumatic encephalopathy is a consequence of repetitive mild traumatic brain injury (rmTBI). These injuries can result in psychiatric disorders that are treated with amitriptyline. Amitriptyline improves neuronal regeneration in major depression via inhibition of acid sphingomyelinase. We hypothesized that acid sphingomyelinase inhibition would preserve neuronal regeneration and decrease depressive symptoms following rmTBI in a murine model. METHODS: A murine model of rmTBI was established using a weight-drop method. Mice were subjected to mTBI every other day for 7 d. Mice received amitriptyline injection 2 h prior to each mTBI. After the final mTBI, mice underwent behavioral studies or biochemical analysis. Hippocampi were analyzed for markers of neurogenesis and phosphorylated tau aggregation. RESULTS: Mice that underwent rmTBI showed increased hippocampal phosphorylated tau aggregation 1 mo following rmTBI as well as decreased neuronal regeneration by bromodeoxyuridine uptake and doublecortin immunohistochemistry. Mice with either genetic deficiency or pharmacologic inhibition of acid sphingomyelinase demonstrated improved neuronal regeneration and decreased phosphorylated tau aggregation compared to untreated rmTBI mice. Behavioral testing showed rmTBI mice spent significantly more time in the dark and waiting to initiate feeding compared to sham mice. These behaviors were partially prevented by the inhibition of acid sphingomyelinase. CONCLUSIONS: We established a murine model of rmTBI that leads to tauopathy, depression, and impaired hippocampal neurogenesis. Inhibition of acid sphingomyelinase prevented the harmful neurologic and behavioral effects of rmTBI. These findings highlight an important opportunity to improve recovery or prevent neuropsychiatric decline in patients at risk for chronic traumatic encephalopathy.

Reliability of recommendations to reduce a fracture of the distal radius.

Background and purpose - It is unclear what degree of malalignment of a fracture of the distal radius benefits from reduction. This study addressed the following questions: (1) What is the interobserver reliability of surgeons concerning the recommendation for a reduction for dorsally displaced distal radius fractures? (2) Do expert-based criteria for reduction improve reliability or not?Methods - We sent out 2 surveys to a group of international hand and fracture surgeons. On the first survey, 80 surgeons viewed radiographs of 95 dorsally displaced (0° to 25°) fractures of the distal radius. The second survey randomized 68 participants to either receive or not receive expert-based criteria for when to reduce a fracture and then viewed 20 radiographs of fractures with dorsal angulation between 5° and 15°. All participants needed to indicate whether they would advise a reduction or not.Results - In the 1st study, the interrater reliability of advising a reduction was fair (kappa 0.31). Multivariable linear regression analyses indicated that each additional degree of dorsal angulation increased the chance of recommending a reduction by 3%. In the 2nd study, reading criteria for reduction did not increase interobserver reliability for recommending a reduction.Interpretation - There is notable variation in recommendations for reduction that is not accounted for by surgeon or patient factors and is not diminished by exposure to expert criteria. Surgeons should be aware of their biases and develop strategies to inform patients and share the decision regarding whether to reduce a fracture of the distal radius.

Therapeutic Inhaled Sphingosine for Treating Lung Infection in a Mouse Model of Critical Illness.

BACKGROUND/AIMS: Sphingosine, a sphingoid long chain base, is a natural lipid with antimicrobial properties. Recent animal studies have shown that preventive sphingosine inhalation can rescue susceptible mice, such as cystic fibrosis-, burn injured- or aged mice from bacterial pulmonary infection. While preventing lung infections in susceptible patients has obvious clinical merit, treatment strategies for an established infection are also direly needed, particularly in the times of rising antibiotic resistance. Here, we tested the potential of sphingosine in treating an established pulmonary infection. METHODS: We used a cecal ligation and puncture (CLP) model in male CF-1 mice and a Pseudomonas aeruginosa strain that was isolated from a septic patient (P. aeruginosa 762). We determined susceptibility to intranasal infection and ascertained when the pulmonary infection was established by continuous core body temperature monitoring. We quantified sphingosine levels in the tracheal epithelium by immunohistochemistry and studied the effects on sphingosine on bacterial membrane permeabilization and intracellular acidification using fluorescent probes. RESULTS: We firstdetermined that septic mice are highly susceptible to P. aeruginosa infection 2 days after indu-cing sepsis. Additionally, at this time, sphingosine levels in the tracheal epithelium are significantly reduced as compared to levels in healthy mice. Secondly, upon intranasal Pseudomonasinoculation, we ascertained that pulmonary infection was established as early as 2.5 h after inoculation as evidenced by a significant drop in core body temperature. Using these times of infection susceptibility and detection (2 days post CLP, 2.5h after inoculation) we treated with inhaled sphingosine and observed pulmonary bacterial loads reduced to levels found in infected healthy mice after inoculation and decreased infection-associated mortality. Further, our data demonstrate that sphingosine induces outer membrane permeabilization, disrupting the membrane potential and leading to intracellular acidification of the bacteria. CONCLUSION: Sphingosine shows efficacy in treating P. aeruginosa lung infections not only prophylactically, but also therapeutically.

Refining the criteria for immediate total-body CT after severe trauma.

OBJECTIVES: Initial trauma care could potentially be improved when conventional imaging and selective CT scanning is omitted and replaced by immediate total-body CT (iTBCT) scanning. Because of the potentially increased radiation exposure by this diagnostic approach, proper selection of the severely injured patients is mandatory. METHODS: In the REACT-2 trial, severe trauma patients were randomized to iTBCT or conventional imaging and selective CT based on predefined criteria regarding compromised vital parameters, clinical suspicion of severe injuries, or high-risk trauma mechanisms in five trauma centers. By logistic regression analysis with backward selection on the 15 study inclusion criteria, a revised set of criteria was derived and subsequently tested for prediction of severe injury and shifts in radiation exposure. RESULTS: In total, 1083 patients were enrolled with median ISS of 20 (IQR 9-29) and median GCS of 13 (IQR 3-15). Backward logistic regression resulted in a revised set consisting of nine original and one adjusted criteria. Positive predictive value improved from 76% (95% CI 74-79%) to 82% (95% CI 80-85%). Sensitivity decreased by 9% (95% CI 7-11%). The area under the receiver operating characteristics curve remained equal and was 0.80 (95% CI 0.77-0.83), original set 0.80 (95% CI 0.77-0.83). The revised set retains 8.78 mSv (95% CI 6.01-11.56) for 36% of the non-severely injured patients. CONCLUSIONS: Selection criteria for iTBCT can be reduced from 15 to 10 clinically criteria. This improves the positive predictive value for severe injury and reduces radiation exposure for less severely injured patients. KEY POINTS: • Selection criteria for iTBCT can be reduced to 10 clinically useful criteria. • This reduces radiation exposure in 36% of less severely injured patients. • Overall discriminative capacity for selection of severely injured patients remained equal.

Highest ambulatory speed using Lokomat gait training for individuals with a motor-complete spinal cord injury: a clinical pilot study.

BACKGROUND: Motor impairment and loss of ambulatory function are major consequences of a spinal cord injury (SCI). Exoskeletons are robotic devices that allow SCI patients with limited ambulatory function to walk. The mean walking speed of SCI patients using an exoskeleton is low: 0.26 m/s. Moreover, literature shows that a minimum speed of 0.59 m/s is required to replace wheelchairs in the community. OBJECTIVE: To investigate the highest ambulatory speed for SCI patients in a Lokomat. METHODS: This clinical pilot study took place in the Rehabilitation Center Kladruby, in Kladruby (Czech Republic). Six persons with motor-complete sub-acute SCI were recruited. Measurements were taken at baseline and directly after a 30 min Lokomat training. The highest achieved walking speed, vital parameters (respiratory frequency, heart rate, and blood pressure), visual analog scale for pain, and modified Ashworth scale for spasticity were recorded for each person. RESULTS: The highest reached walking speed in the Lokomat was on average 0.63 m/s (SD 0.03 m/s). No negative effects on the vital parameters, pain, or spasticity were observed. A significant decrease in pain after the Lokomat training was observed: 95% CI [0.336, 1.664] (p = 0.012). CONCLUSION: This study shows that it is possible for motor-complete SCI individuals to ambulate faster on a Lokomat (on average 0.63 m/s) than what is currently possible with over-ground exoskeletons. No negative effects were observed while ambulating on a Lokomat. Further research investigating walking speed in exoskeletons after SCI is recommended.

Telemedicine Based Remote Home Monitoring After Liver Transplantation: Results of a Randomized Prospective Trial.

OBJECTIVE: This study assesses the impact of a telemedicine-based home management program (THMP) on patient adherence, hospital readmissions, and quality of life (QOL) after liver transplantation (LT). SUMMARY OF BACKGROUND DATA: Telemedicine interventions represent an opportunity to personalize care and can lead to improved adherence and patient satisfaction. However, there is limited data on impact of these interventions on outcomes after LT. Therefore, we conducted the first randomized controlled trial (RCT) of a THMP compared to standard of care (SOC) after LT. METHODS: One hundred six consecutive LT recipients were randomized (1:1) to 1 of 2 posttransplant care strategies: SOC or THMP. The THMP included an electronic tablet and bluetooth devices to support daily text messages, education videos, and video FaceTime capability; data was cyber-delivered into our electronic medical record daily. Endpoints were THMP participation, 90-day hospital readmission rate, and QOL. RESULTS: One hundred patients completed the study with 50 enrolled in each arm. Participation and adherence with telemedicine was 86% for basic health sessions (vital sign recording), but only 45% for using messaging or FaceTime. The THMP group had a lower 90-day readmission rate compared to SOC (28% vs 58%; P = 0.004). The THMP cohort also showed improved QOL in regards to physical function (P = 0.02) and general health (P = 0.05) at 90 days. CONCLUSIONS: To our knowledge, this is the first RCT demonstrating the impact of THMP after LT. The magnitude of effect on LT outcomes, hospital readmissions, and QOL suggests that the adoption of telemedicine has great potential for other major operations.