Limitations in a frataxin knockdown cell model for Friedreich ataxia in a high-throughput drug screen

<p>Abstract</p> <p>Background</p> <p>Pharmacological high-throughput screening (HTS) represents a powerful strategy for drug discovery in genetic diseases, particularly when the full spectrum of pathological dysfunctions remains unclear, such as in Friedreich ataxia (FRDA). FRDA, the most common recessive ataxia, results from a generalized deficiency of mitochondrial and cytosolic iron-sulfur cluster (ISC) proteins activity, due to a partial loss of frataxin function, a mitochondrial protein proposed to function as an iron-chaperone for ISC biosynthesis. In the absence of measurable catalytic function for frataxin, a cell-based assay is required for HTS assay.</p> <p>Methods</p> <p>Using a targeted ribozyme strategy in murine fibroblasts, we have developed a cellular model with strongly reduced levels of frataxin. We have used this model to screen the Prestwick Chemical Library, a collection of one thousand off-patent drugs, for potential molecules for FRDA.</p> <p>Results</p> <p>The frataxin deficient cell lines exhibit a proliferation defect, associated with an ISC enzyme deficit. Using the growth defect as end-point criteria, we screened the Prestwick Chemical Library. However no molecule presented a significant and reproducible effect on the proliferation rate of frataxin deficient cells. Moreover over numerous passages, the antisense ribozyme fibroblast cell lines revealed an increase in frataxin residual level associated with the normalization of ISC enzyme activities. However, the ribozyme cell lines and FRDA patient cells presented an increase in Mthfd2 transcript, a mitochondrial enzyme that was previously shown to be upregulated at very early stages of the pathogenesis in the cardiac mouse model.</p> <p>Conclusion</p> <p>Although no active hit has been identified, the present study demonstrates the feasibility of using a cell-based approach to HTS for FRDA. Furthermore, it highlights the difficulty in the development of a stable frataxin-deficient cell model, an essential condition for productive HTS in the future.</p

Evaluating trauma center structural performance: The experience of a Canadian provincial trauma system

Background: Indicators of structure, process, and outcome are required to evaluate the performance of trauma centers to improve the quality and efficiency of care. While periodic external accreditation visits are part of most trauma systems, a quantitative indicator of structural performance has yet to be proposed. The objective of this study was to develop and validate a trauma center structural performance indicator using accreditation report data. Materials and Methods: Analyses were based on accreditation reports completed during on-site visits in the Quebec trauma system (1994-2005). Qualitative report data was retrospectively transposed onto an evaluation grid and the weighted average of grid items was used to quantify performance. The indicator of structural performance was evaluated in terms of test-retest reliability (kappa statistic), discrimination between centers (coefficient of variation), content validity (correlation with accreditation decision, designation level, and patient volume) and forecasting (correlation between visits performed in 1994-1999 and 1998-2005). Results: Kappa statistics were >0.8 for 66 of the 73 (90%) grid items. Mean structural performance score over 59 trauma centers was 47.4 (95% CI: 43.6-51.1). Two centers were flagged as outliers and the coefficient of variation was 31.2% (95% CI: 25.5% to 37.6%), showing good discrimination. Correlation coefficients of associations with accreditation decision, designation level, and volume were all statistically significant (r = 0.61, -0.40, and 0.24, respectively). No correlation was observed over time (r = 0.03). Conclusion: This study demonstrates the feasibility of quantifying trauma center structural performance using accreditation reports. The proposed performance indicator shows good test-retest reliability, between-center discrimination, and construct validity. The observed variability in structural performance across centers and over-time underlines the importance of evaluating structural performance in trauma systems at regular intervals to drive quality improvement efforts

Road traffic accident-related thoracic trauma: Epidemiology, injury pattern, outcome, and impact on mortality?A multicenter observational study

Background Thoracic trauma is a major cause of death in trauma patients and road traffic accident (RTA)-related thoracic injuries have different characteristics than those with non-RTA related thoracic traumas, but this have been poorly described. The main objective was to investigate the epidemiology, injury pattern and outcome of patients suffering a significant RTA-related thoracic injury. Secondary objective was to investigate the influence of serious thoracic injuries on mortality, compared to other serious injuries. Methods We performed a multicenter observational study including patients of the Rhône RTA registry between 1997 and 2016 sustaining a moderate to lethal (Abbreviated Injury Scale, AIS?2) injury in any body region. A subgroup (AISThorax?2 group) included those with one or more AIS?2 thoracic injury. Descriptive statistics were performed for the main outcome and a multivariate logistic regression was computed for our secondary outcome. Results A total of 176,346 patients were included in the registry and 6,382 (3.6%) sustained a thoracic injury. Among those, median age [IQR] was 41 [25-58] years, and 68.9% were male. The highest incidence of thoracic injuries in female patients was in the 70-79 years age group, while this was observed in the 20-29 years age group among males. Most patients were car occupants (52.3%). Chest wall injuries were the most frequent thoracic injuries (62.1%), 52.4% of which were multiple rib fractures. Trauma brain injuries (TBI) were the most frequent concomitant injuries (29.1%). The frequency of MAISThorax = 2 injuries increased with age while that of MAISThorax = 3 injuries decreased. A total of 16.2% patients died. Serious (AIS?3) thoracic injuries (OR = 12.4, 95%CI [8.6;18.0]) were strongly associated with mortality but less than were TBI (OR = 27.9, 95%CI [21.3;36.7]). Conclusion Moderate to lethal RTA-related thoracic injuries were rare. Multiple ribs fractures, pulmonary contusions, and sternal fractures were the most frequent anatomical injuries. The incidence, injury pattern and mechanisms greatly vary across age groups

Characteristics of patients included and enrolled in studies on the prognostic value of serum biomarkers for prediction of postconcussion symptoms following a mild traumatic brain injury:A systematic review

Objective: Mild traumatic brain injury (mTBI) has been insufficiently researched and its definition remains elusive. Investigators are confronted by heterogeneity in patients, mechanism of injury and outcomes. Findings are thus often limited in generalizability and clinical application. Serum protein biomarkers are increasingly assessed to enhance prognostication of outcomes but their translation into clinical practice has yet to be achieved. A systematic review was performed to describe the adult populations included and enrolled in studies that evaluated the prognostic value of protein biomarkers to predict post-concussion symptoms following a mTBI. Data sources: Searches of MEDLINE, EMBASE, CENTRAL, CINAHL, Web of Science, PsycBITE, and PsycINFO up to October 2016. Data selection and extraction: Two reviewers independently screened for potentially eligible studies, extracted data and assessed the overall quality of evidence by outcome using the Grading of Recommendations Assessment, Development and Evaluation approach. Results: A total of 23,298 citations were obtained from which 166 manuscripts were reviewed. Thirty-six cohort studies (2,812 patients) having enrolled between 7 and 311 patients (median 89) fulfilled our inclusion criteria. Most studies excluded patients based on advanced age (n=10 (28%)), neurologic disorders (n=20 (56%)), psychiatric disorders (n=17 (47%)), substance abuse disorders (n=13 (36%)) or previous TBI (n=10 (28%)). Twenty-one studies (58%) used at least two of these exclusion criteria. The pooled mean age of included patients was 39.3 (SD 4.6) years old (34 studies). The criteria used to define a mTBI were inconsistent. The most frequently reported outcome was post-concussion syndrome (PCS) using the Rivermead Post-Concussion Symptoms Questionnaire (n=18 (50%)) with follow-ups ranging from 7 days to 5 years after the mTBI. Conclusions: Most studies have recruited samples that are not representative and generalizable to the mTBI population. These exclusion criteria limit the potential use and translation of promising serum protein biomarkers to predict post-concussion symptoms

Accuracy of a Prehospital Triage Protocol in Predicting In-Hospital Mortality and Severe Trauma Cases among Older Adults

Background: Prehospital trauma triage tools are not tailored to identify severely injured older adults. Our trauma triage protocol based on a three-tier trauma severity grading system (A, B, and C) has never been studied in this population. The objective was to assess its accuracy in predicting in-hospital mortality among older adults (&ge;65 years) and to compare it to younger patients. Methods: A retrospective multicenter cohort study, from 2011 to 2021. Consecutive adult trauma patients managed by a mobile medical team were prospectively graded A, B, or C according to the initial seriousness of their injuries. Accuracy was evaluated using sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios. Results: 8888 patients were included (14.1% were &ge;65 years). Overall, 10.1% were labeled Grade A (15.2% vs. 9.3% among older and younger adults, respectively), 21.9% Grade B (27.9% vs. 20.9%), and 68.0% Grade C (56.9% vs. 69.8%). In-hospital mortality was 7.1% and was significantly higher among older adults regardless of severity grade. Grade A showed lower sensitivity (50.5 (43.7; 57.2) vs. 74.6 (69.8; 79.1), p &lt; 0.0001) for predicting mortality among older adults compared to their younger counterparts. Similarly, Grade B was associated with lower sensitivity (89.5 (84.7; 93.3) vs. 97.2 (94.8; 98.60), p = 0.0003) and specificity (69.4 (66.3; 72.4) vs. 74.6 (73.6; 75.7], p = 0.001) among older adults. Conclusions: Our prehospital trauma triage protocol offers high sensitivity for predicting in-hospital mortality including older adults