Le traumatisme crânien (TCC) léger et le multitraumatisme orthopédique comme facteurs de risque sur l’incidence d’ossification hétérotopique chez une population orthopédique : étude de dossiers

Essai doctoral présenté à la Faculté des arts et des sciences en vue de l'obtention du grade de Doctorat en psychologie - option psychologie clinique (D.Psy.)Contexte théorique : L’ossification hétérotopique (OH), une formation osseuse anormale dans les tissus extra-squelettiques, est une complication post-fracture isolée d’un membre (FIM) provoquant des altérations fonctionnelles importantes qui ne peut être prévenue cliniquement. Les traumatismes crâniens (TCC) modérés/sévères sont connus comme facteurs de risque d’OH chez les patients orthopédiques (PO). De récentes études ont étudié le développement d’OH chez les patients ayant un TCC léger concomitant d’une fracture, ajoutant le TCC léger comme facteur de risque d’OH. À notre connaissance, aucune étude n’a étudié le TCC léger (TCCL) concomitant et le multitraumatisme orthopédique (MO; présence simultanée de plus d’une fracture) comme facteurs liés au développement de l’OH. Objectif : L’objectif de cette étude était d’évaluer le TCC léger concomitant et le MO comme facteurs liés au développement d’OH chez une population orthopédique. Méthodes : Cette étude rétrospective de dossiers incluant des patients ayant une FMI ou un MO avec/sans TCC léger concomitant, recrutés dans deux projets antérieurs menés à l’Hôpital du Sacré-Cœur de Montréal (HSCM). Les patients ayant un TCC léger concomitant ont reçu leur diagnostic de TCC léger à l’urgence post-accident. Les participants orthopédiques retenus dans l’échantillon avaient obtenu un suivi de leur(s) fracture(s) d’au moins 45 jours post-accident. Une cohorte de patients orthopédiques avec/sans TCC léger concomitant, appariée selon l’âge, le sexe, le type de fracture et le nombre de fractures, a été utilisée pour contrôler le lien possible entre ces facteurs et le développement d’OH. La cueillette de données et l’appariement des participants ont été effectués par la chercheure principale. Une analyse des radiographies à environ trois mois post-trauma chez 121 patients orthopédiques a été effectuée par quatre spécialistes (une chercheure orthopédique [évaluateur 1] et trois médecins résidents [partageant la tâche de l’évaluateur 2]), afin d’évaluer les signes d’OH autour du site des fractures. Les évaluateurs ont utilisé la classification de Toom (2005) pour diagnostiquer l’OH sur radiographie. Résultats : L’échantillon comptait 121 patients (femmes = 58; âge moyen = 54,06) et a été divisé en quatre groupes (33 TCCL+FMI, 28TCCL+MO, 29FMI et 31MO) en fonction de la présence d’un TCC léger concomitant, puis de celle d’un multitraumatisme orthopédique. La présence d’OH était significativement plus élevée chez les 59 patients de l’échantillon ayant un multitraumatisme orthopédique (X² = 4,30, p = 0,0381), comparativement aux patients ayant un monotraumatisme orthopédique (avec ou sans TCC léger concomitant). La présence d’OH n’était pas significativement plus élevée chez les 61 patients de l’échantillon ayant subi un TCC léger concomitant d’un monotraumatisme ou d’un multitraumatisme orthopédique (X² = 0,08, p = 0,77). Conclusions : La présence d’OH chez les patients orthopédiques avec ou sans TCC léger concomitant de l’échantillon serait significativement associée à la présence d’un multitraumatisme orthopédique (de plusieurs fractures simultanées) et ce, en contrôlant statistiquement des facteurs connus comme pouvant influencer le développement de l’OH. Des études ultérieures portant sur les facteurs de risque et les mécanismes pathophysiologiques de complications (p. ex., l’OH) chez des patients ayant subi des blessures traumatiques seraient pertinentes pour permettre de mieux comprendre les risques d’OH.Theoretical background: Heterotopic ossification (HO), an abnormal bone formation in extra skeletal tissues, is a non-negligible complication that can occur following an isolated limb fracture (ILF) causing significant functional alterations and whose development cannot be prevented clinically. Moderate/severe traumatic brain or head injury (TBI) is known to be a risk factor for HO in polytrauma orthopedic (PO) patients (with multiple concurrent severe traumas). Recent studies have identified mild TBI as a risk factor for the development of HO in patients with isolated limb fracture (ILF). There are no studies to our knowledge that have investigated OH risks in patients who have sustained multiple orthopaedic injuries (MO) and concomitant mTBI. Objective: The objective of this study was to evaluate concomitant mild TBI and orthopedic multitrauma as factors related to the development of HO. Methods: This study was a retrospective chart review including patients with orthopedic monotrauma (one fracture) or orthopedic multitrauma (multiple fractures) with/without concomitant mild TBI recruited from two previous research projects conducted at a level 1 trauma hospital (Sacre-Cœur’s Hospital). Patients with concomitant mild TBI with one or more fractures were diagnosed with mild TBI in the Hospital emergency department using the Glasgow Coma Scale. Orthopedic patients included in this study had to have benefited from a 45-day medical follow-up after their fracture(s). Next, a cohort of patients with one or more fractures with/without concomitant mTBI, matched for age, sex, fracture type, and number of fractures, was used to control for the possible association between known HO risk factors and the development of HO (age, sex, injury type, number of fractures). Data collection and participant matching were performed by an expert evaluator. Radiographs examination of fractured bones at approximately 3 months postinjury in 121 orthopedic patients was performed by four specialists including an orthopedic surgeon/clinical researcher (performing the task of Assessor 1) and three orthopaedic surgeon residents (sharing the task of Assessor 2), to assess signs of HO around each patient's fracture site. The raters used a classification combining the Brooker and Della's Valle classifications proposed by Toom (2005) to diagnose signs of OH on radiography. Results: The complete sample consisted of 121 patients (women = 58; mean age = 54.06) which was subdivided into four groups (33 mTBI+OM, 28mTMI+ILF, 29ILF, and 31OM) according to the presence/absence of a concomitant mild TCC and the presence/absence of orthopedic multitrauma. The frequency of HO detection was significantly higher among the 59 OM patients with/without concomitant mild TBI (X² = 4.30, p = 0.04) relative to ILF patients with/without concomitant mild TBI. The frequency of HO detection did not statistically differ between orthopaedic patients who had sustained a concomitant mild TBI relative to orthopaedic patients without concomitant mild TBI (X² = 0.08, p = 0.77). Conclusions: These study findings suggest that patients with OM are significantly more at risk of exhibiting signs of HO than monotrauma orthopaedic patients. Further studies on the risk factors and pathophysiological mechanisms of HO in patients with traumatic injuries would be pertinent to further our understanding of HO risks

Structural and antimicrobial properties of human pre-elafin/trappin-2 and derived peptides against Pseudomonas aeruginosa

<p>Abstract</p> <p>Background</p> <p>Pre-elafin/trappin-2 is a human innate defense molecule initially described as a potent inhibitor of neutrophil elastase. The full-length protein as well as the N-terminal "cementoin" and C-terminal "elafin" domains were also shown to possess broad antimicrobial activity, namely against the opportunistic pathogen <it>P. aeruginosa</it>. The mode of action of these peptides has, however, yet to be fully elucidated. Both domains of pre-elafin/trappin-2 are polycationic, but only the structure of the elafin domain is currently known. The aim of the present study was to determine the secondary structures of the cementoin domain and to characterize the antibacterial properties of these peptides against <it>P. aeruginosa</it>.</p> <p>Results</p> <p>We show here that the cementoin domain adopts an α-helical conformation both by circular dichroism and nuclear magnetic resonance analyses in the presence of membrane mimetics, a characteristic shared with a large number of linear polycationic antimicrobial peptides. However, pre-elafin/trappin-2 and its domains display only weak lytic properties, as assessed by scanning electron micrography, outer and inner membrane depolarization studies with <it>P. aeruginosa </it>and leakage of liposome-entrapped calcein. Confocal microscopy of fluorescein-labeled pre-elafin/trappin-2 suggests that this protein possesses the ability to translocate across membranes. This correlates with the finding that pre-elafin/trappin-2 and elafin bind to DNA <it>in vitro </it>and attenuate the expression of some <it>P. aeruginosa </it>virulence factors, namely the biofilm formation and the secretion of pyoverdine.</p> <p>Conclusions</p> <p>The N-terminal cementoin domain adopts α-helical secondary structures in a membrane mimetic environment, which is common in antimicrobial peptides. However, unlike numerous linear polycationic antimicrobial peptides, membrane disruption does not appear to be the main function of either cementoin, elafin or full-length pre-elafin/trappin-2 against <it>P. aeruginosa</it>. Our results rather suggest that pre-elafin/trappin-2 and elafin, but not cementoin, possess the ability to modulate the expression of some <it>P.aeruginosa </it>virulence factors, possibly through acting on intracellular targets.</p

Moderate to severe acute pain disturbs motor cortex intracortical inhibition and facilitation in orthopedic trauma patients : a TMS study

Objective Primary motor (M1) cortical excitability alterations are involved in the development and maintenance of chronic pain. Less is known about M1-cortical excitability implications in the acute phase of an orthopedic trauma. This study aims to assess acute M1-cortical excitability in patients with an isolated upper limb fracture (IULF) in relation to pain intensity. Methods Eighty-four (56 IULF patients <14 days post-trauma and 28 healthy controls). IULF patients were divided into two subgroups according to pain intensity (mild versus moderate to severe pain). A single transcranial magnetic stimulation (TMS) session was performed over M1 to compare groups on resting motor threshold (rMT), short-intracortical inhibition (SICI), intracortical facilitation (ICF), and long-interval cortical inhibition (LICI). Results Reduced SICI and ICF were found in IULF patients with moderate to severe pain, whereas mild pain was not associated with M1 alterations. Age, sex, and time since the accident had no influence on TMS measures. Discussion These findings show altered M1 in the context of acute moderate to severe pain, suggesting early signs of altered GABAergic inhibitory and glutamatergic facilitatory activities

Effect of Hydrocortisone on Mortality and Organ Support in Patients With Severe COVID-19: The REMAP-CAP COVID-19 Corticosteroid Domain Randomized Clinical Trial.

Importance: Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited. Objective: To determine whether hydrocortisone improves outcome for patients with severe COVID-19. Design, Setting, and Participants: An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin. Between March 9 and June 17, 2020, 614 adult patients with suspected or confirmed COVID-19 were enrolled and randomized within at least 1 domain following admission to an intensive care unit (ICU) for respiratory or cardiovascular organ support at 121 sites in 8 countries. Of these, 403 were randomized to open-label interventions within the corticosteroid domain. The domain was halted after results from another trial were released. Follow-up ended August 12, 2020. Interventions: The corticosteroid domain randomized participants to a fixed 7-day course of intravenous hydrocortisone (50 mg or 100 mg every 6 hours) (n = 143), a shock-dependent course (50 mg every 6 hours when shock was clinically evident) (n = 152), or no hydrocortisone (n = 108). Main Outcomes and Measures: The primary end point was organ support-free days (days alive and free of ICU-based respiratory or cardiovascular support) within 21 days, where patients who died were assigned -1 day. The primary analysis was a bayesian cumulative logistic model that included all patients enrolled with severe COVID-19, adjusting for age, sex, site, region, time, assignment to interventions within other domains, and domain and intervention eligibility. Superiority was defined as the posterior probability of an odds ratio greater than 1 (threshold for trial conclusion of superiority >99%). Results: After excluding 19 participants who withdrew consent, there were 384 patients (mean age, 60 years; 29% female) randomized to the fixed-dose (n = 137), shock-dependent (n = 146), and no (n = 101) hydrocortisone groups; 379 (99%) completed the study and were included in the analysis. The mean age for the 3 groups ranged between 59.5 and 60.4 years; most patients were male (range, 70.6%-71.5%); mean body mass index ranged between 29.7 and 30.9; and patients receiving mechanical ventilation ranged between 50.0% and 63.5%. For the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively, the median organ support-free days were 0 (IQR, -1 to 15), 0 (IQR, -1 to 13), and 0 (-1 to 11) days (composed of 30%, 26%, and 33% mortality rates and 11.5, 9.5, and 6 median organ support-free days among survivors). The median adjusted odds ratio and bayesian probability of superiority were 1.43 (95% credible interval, 0.91-2.27) and 93% for fixed-dose hydrocortisone, respectively, and were 1.22 (95% credible interval, 0.76-1.94) and 80% for shock-dependent hydrocortisone compared with no hydrocortisone. Serious adverse events were reported in 4 (3%), 5 (3%), and 1 (1%) patients in the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively. Conclusions and Relevance: Among patients with severe COVID-19, treatment with a 7-day fixed-dose course of hydrocortisone or shock-dependent dosing of hydrocortisone, compared with no hydrocortisone, resulted in 93% and 80% probabilities of superiority with regard to the odds of improvement in organ support-free days within 21 days. However, the trial was stopped early and no treatment strategy met prespecified criteria for statistical superiority, precluding definitive conclusions. Trial Registration: ClinicalTrials.gov Identifier: NCT02735707

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P &lt; 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Étude du mode d'action antimicrobien de la pré-élafine contre Pseudomonas aeruginosa

Pseudomonas aeruginosa (Pa) est un pathogène opportuniste et constitue un facteur de morbidité et de mortalité important chez les patients atteints de fibrose kystique II est responsable d'infections pulmonaires chroniques. Sa capacité à se maintenir chez l'hôte et à causer des infections résulte de l'expression de nombreux facteurs de virulence. Le traitement à l'aide d'antibiotiques fonctionne pour une durée limitée selon la capacité de Pa à développer de la résistance. Il est donc impératif de trouver d'autres alternatives afin de traiter les patients atteints de ce type d'infections chroniques. Les peptides antibactériens sont une des avenues envisagées puisque leurs cibles sont différentes et qu'ils n'engendrent pas de résistance. Par contre, les modes d'action des peptides antibactériens comme la pré-élafine sont encore mal connus. La pré-élafine est une protéine humaine sécrétée notamment par les cellules épithéliales. Elle possède des propriétés inhibitrices contre certaines peptidases à serine ainsi que des propriétés antimicrobiennes contre différentes souches de levures et de bactéries, incluant Pa. Nous avons étudié le mode d'action antibactérien de la pré-élafine contre Pa à l'aide de différentes approches. Nous avons d'abord observé que toutes les souches de Pa ne sont pas affectées de la même manière par la pré-élafine. La souche PA33348 est particulièrement sensible. Nous avons montré que cette hypersensibilité résulte de l'inhibition spécifique par le domaine élafine d'une peptidase sécrétée par cette souche, la peptidase IV, ce qui, affecte la croissance et/ou la viabilité en milieu complexe. Nous avons également montré que la pré-élafine et chacun de ses deux domaines se lie aux membranes. Le domaine N-terminal, ou cementoïne, qui est polycationique se lie plus particulièrement aux membranes chargées négativement. À l'aide de différentes techniques dont le dichroïsme circulaire et la résonance magnétique nucléaire, nous avons montré que ce domaine est peu structuré en solution aqueuse, mais adopte une conformation en hélices a dans un environnement hydrophobe. Cette caractéristique est commune à un grand nombre de peptides antimicrobiens, la plupart ayant la capacité de détruire l'intégrité des membranes microbiennes. Toutefois, et contrairement à ces peptides, les domaines cementoïne, élafine et la pré-élafine ne possèdent qu'une faible activité lytique. Par contre, nos résultats suggèrent que la pré-élafine aurait la capacité de traverser les membranes biologiques sans causer de lyse. Bien que d'autres expériences soient nécessaires pour confirmer cette hypothèse de la translocation au travers des membranes de la pré-élafine, nous avons montré que in vitro le domaine élafine et la pré-élafine, mais non la cementoïne, peuvent se lier à l'ADN. De plus nous avons noté une corrélation entre cette caractéristique et le fait que ces deux peptides permettent de diminuer l'expression de plusieurs facteurs de virulence de Pa. En résumé, nos travaux ont contribué à mieux comprendre les mécanismes d'action de la pré-élafine contre Pa. Cette protéine pourrait devenir une solution dans le traitement des patients atteints de fibrose kystique. Des études à l'aide de modèles animaux seraient le moyen idéal de confirmer notre travail et poursuivre la recherche sur le potentiel thérapeutique de la pré-élafine ou de ses domaines

Human Pre-Elafin Inhibits a Pseudomonas aeruginosa-Secreted Peptidase and Prevents Its Proliferation in Complex Media▿

Pseudomonas aeruginosa is a life-threatening opportunist human pathogen frequently associated with lung inflammatory diseases, namely, cystic fibrosis. Like other species, this gram-negative bacteria is increasingly drug resistant. During the past decade, intensive research efforts have been focused on the identification of natural innate defense molecules with broad antimicrobial activities, collectively known as antimicrobial peptides. Human pre-elafin, best characterized as a potent inhibitor of neutrophil elastase with anti-inflammatory properties, was also shown to possess antimicrobial activity against both gram-positive and gram-negative bacteria, including P. aeruginosa. Its mode of action was, however, not known. Using full-length pre-elafin, each domain separately, and mutated variants of pre-elafin with attenuated antipeptidase activity toward neutrophil elastase, we report here that both pre-elafin domains contribute, through distinct mechanisms, to its antibacterial activity against Pseudomonas aeruginosa. Most importantly, we demonstrate that the whey acidic protein (WAP) domain specifically inhibits a secreted peptidase with the characteristics of arginyl peptidase (protease IV). This is the first demonstration that a human WAP-motif protein inhibits a secreted peptidase to prevent bacterial growth in vitro. Since several WAP-motif proteins from various species demonstrate antimicrobial function with variable activities toward bacterial species, we suggest that this mechanism may be more common than initially anticipated

Characterization of human pre-elafin mutants: full antipeptidase activity is essential to preserve lung tissue integrity in experimental emphysema

Pre-elafin is a tight-binding inhibitor of neutrophil elastase and myeloblastin; two enzymes thought to contribute to tissue damage in lung emphysema. Previous studies have established that pre-elafin is also an effective anti-inflammatory molecule. However, it is not clear whether both functions are linked to the antipeptidase activity of pre-elafin. As a first step toward elucidating the structure/function relationship of this protein, we describe here the construction and characterization of pre-elafin variants with attenuated antipeptidase potential. In these mutants, the P1′ methionine residue of the inhibitory loop is replaced by either a lysine (pre-elafinM25K) or a glycine (pre-elafinM25G) residue. Both mutated variants are stable and display biochemical properties undistinguishable from WT (wild-type) pre-elafin. However, compared with WT pre-elafin, their inhibitory constants are increased by one to four orders of magnitude toward neutrophil elastase, myeloblastin and pancreatic elastase, depending on the variants and enzymes tested. As suggested by molecular modelling, this attenuated inhibitory potential correlates with decreased van der Waals interactions between the variants and the enzymes S1′ subsite. In elastase-induced experimental emphysema in mice, only WT pre-elafin protected against tissue destruction, as assessed by the relative airspace enlargement measured using lung histopathological sections. Pre-elafin and both mutants prevented transient neutrophil alveolitis. However, even the modestly affected pre-elafinM25K mutant, as assayed in vitro with small synthetic substrates, was a poor inhibitor of the neutrophil elastase and myeloblastin elastolytic activity measured with insoluble elastin. We therefore conclude that full antipeptidase activity of pre-elafin is essential to protect against lung tissue lesions in this experimental model