Animal models to assess the local and systemic effects of nailing: Review of the literature and considerations for future studies

Systemic acylcarnitine levels are affected in response to multiple injuries and hemorrhagic shock: An analysis of lipidomic changes in a standardized porcine model

INTRODUCTION

Along with recent advances in analytical technologies, tricarboxylic acid-cycle intermediates are increasingly identified as promising makers for cellular ischemia and mitochondrial dysfunction during hemorrhagic shock. For traumatized patients, the knowledge of the role of lipid oxidation substrates is sparse. In this study, we aimed to analyze the dynamics of systemic acylcarnitine (AcCa) release in a standardized polytrauma model with hemorrhagic shock.

METHODS

Fifty-two male pigs (50 ± 5 kg) were randomized into two groups: group isolated fracture was subject to a standardized femur shaft fracture, and group polytrauma was subject to a femur fracture, followed by blunt chest trauma, liver laceration, and a pressure-controlled hemorrhagic shock for 60 minutes. Resuscitation was performed with crystalloids. Fractures were stabilized by intramedullary nailing. Venous samples were collected at six time points (baseline, trauma, resuscitation, 2 hours, 4 hours, and 6 hours). Lipidomic analysis was performed via liquid chromatography coupled mass spectrometry. Measurements were collated with clinical markers and near-infrared spectrometry measurements of tissue perfusion. Longitudinal analyses were performed with linear mixed models, and Spearman's correlations were calculated. A p value of 0.05 was defined as threshold for statistical significance.

RESULTS

From a total of 303 distinct lipids, we identified two species of long-chain AcCas. Both showed a highly significant ( p < 0.001) twofold increase after hemorrhagic shock in group polytrauma that promptly normalized after resuscitation. This increase was associated with a significant decrease of the base excess ( p = 0.005), but recovery after resuscitation was faster. For both AcCas, there were significant correlations with decreased muscle tissue oxygen delivery ( p = 0.008, p = 0.003) and significant time-lagged correlations with the increase of creatine kinase ( p < 0.001, p < 0.001).

CONCLUSION

Our results point to plasma AcCas as a possible indicator for mitochondrial dysfunction and cellular ischemia in hemorrhagic shock. The more rapid normalization after resuscitation in comparison with acid base changes may warrant further investigation.

How to detect a polytrauma patient at risk of complications: A validation and database analysis of four published scales

Introduction

Early accurate assessment of the clinical status of severely injured patients is crucial for guiding the surgical treatment strategy. Several scales are available to differentiate between risk categories. They vary between expert recommendations and scores developed on the basis of patient data (level II). We compared four established scoring systems in regard to their predictive abilities for early (e.g., hemorrhage-induced mortality) versus late (Multiple Organ Failure (MOF), sepsis, late death) in-hospital complications.

Methods

A database from a level I trauma center was used. The inclusion criteria implied an injury severity score (ISS) of ≥16 points, primary admission, and a complete data set from admission to hospital-day 21. The following four scales were tested: the clinical grading scale (CGS; covers acidosis, shock, coagulation, and soft tissue injuries), the modified clinical grading scale (mCGS; covers CGS with modifications), the polytrauma grading score (PTGS; covers shock, coagulation, and ISS), and the early appropriate care protocol (EAC; covers acid–base changes). Admission values were selected from each scale and the following endpoints were compared: mortality, pneumonia, sepsis, death from hemorrhagic shock, and multiple organ failure.

Statistics

Shapiro-Wilk test for normal distribution, Pearson Chi square, odds ratios (OR) for all endpoints, 95% confidence intervals. Fitted, generalized linear models were used for prediction analysis. Krippendorff was used for comparison of CGS and mCGS. Alpha set at 0.05.

Results

In total, 3668 severely injured patients were included (mean age, 45.8±20 years; mean ISS, 28.2±15.1 points; incidence of pneumonia, 19.0%; incidence of sepsis, 14.9%; death from hem. shock, 4.1%; death from multiple organ failure (MOF), 1.9%; mortality rate, 26.8%). Our data show distinct differences in the prediction of complications, including mortality, for these scores (OR ranging from 0.5 to 9.1). The PTGS demonstrated the highest predictive value for any late complication (OR = 2.0), sepsis (OR = 2.6, p = 0.05), or pneumonia (OR = 2.0, p = 0.2). The EAC demonstrated good prediction for hemorrhage-induced early mortality (OR = 7.1, p<0.0001), but did not predict late complications (sepsis, OR = 0.8 and p = 0.52; pneumonia, OR = 1.1 and p = 0.7) CGS and mCGS are not comparable and should not be used interchangeably (Krippendorff α = 0.045).

Conclusion

Our data show that prediction of complications is more precise after using values that covers different physiological systems (coagulation, hemorrhage, acid–base changes, and soft tissue damage) when compared with using values of only one physiological system (e.g., acidosis). When acid–base changes alone were tested in terms of complications, they were predictive of complications within 72 hours but failed to predict late complications. These findings should be considered when performing early assessment of trauma patients or for the development of new scores.

Inhalative IL-10 treatment after bilateral femoral fractures affect pulmonary inflammation in mice

BACKGROUND

Musculoskeletal injuries induce systemic inflammation which often impairs lung function contributing to morbidity. IL-10 has been shown to have a beneficial effect on immune dysfunction and organ damage after different traumatic insults. We sought to investigate the effect of inhalative IL-10 administration on the systemic and pulmonary inflammatory response in a small animal model of bilateral femoral fracture.

MATERIALS AND METHODS

Male C57/BL6 mice (6 animals per group) were subjected to bilateral femoral fracture and intramedullary nailing followed by inhalative administration of either 50μL PBS (Fx group) or 50μg/kg recombinant mouse IL-10 dissolved in 50μL PBS (FxIL-10 group). All animals were sacrificed at 6, 24, or 72h after fracture induction. Blood samples were collected and analyzed for IL-6, IL-10, KC, and MCP-1 (CCL2) plasma concentrations by Bio-Plex Pro™ assays. Pulmonary infiltration by neutrophils was assessed by myeloperoxidase (MPO) activity (ELISA) and histological analysis of lung tissue. Pulmonary ICAM-1 expression (immunohistochemistry), and pulmonary IL-6 levels (ELISA) were determined.

RESULTS

Inhalative IL-10 administration showed a decrease in the pulmonary infiltration by neutrophils. A significant decrease in the expression of the adhesion molecule ICAM-1 after local IL-10 application was observed. In contrast, local IL-10 administration did not show a significant effect on the systemic inflammatory response.

CONCLUSION

Our findings suggest that inhalative IL-10 administration may beneficially modulate the pulmonary microenvironment, in which IL-10 effect on the local ICAM-1 expression seems to play a central role.