I-FABP as a Potential Marker for Intestinal Barrier Loss in Porcine Polytrauma

Polytrauma and concomitant hemorrhagic shock can lead to intestinal damage and subsequent multiple organ dysfunction syndrome. The intestinal fatty acid-binding protein (I-FABP) is expressed in the intestine and appears quickly in the circulation after intestinal epithelial cell damage. This porcine animal study investigates the I-FABP dynamics in plasma and urine after polytrauma. Furthermore, it evaluates to what extent I-FABP can also act as a marker of intestinal damage in a porcine polytrauma model. Eight pigs (Sus scrofa) were subjected to polytrauma which consisted of lung contusion, tibial fracture, liver laceration, and hemorrhagic shock followed by blood and fluid resuscitation and fracture fixation with an external fixator. Eight sham animals were identically instrumented but not injured. Afterwards, intensive care treatment including mechanical ventilation for 72 h followed. I-FABP levels in blood and urine were determined by ELISA. In addition, immunohistological staining for I-FABP, active caspase-3 and myeloperoxidase were performed after 72 h. Plasma and urine I-FABP levels were significantly increased shortly after trauma. I-FABP expression in intestinal tissue showed significantly lower expression in polytraumatized animals vs. sham. Caspase-3 and myeloperoxidase expression in the immunohistological examination were significantly higher in the jejunum and ileum of polytraumatized animals compared to sham animals. This study confirms a loss of intestinal barrier after polytrauma which is indicated by increased I-FABP levels in plasma and urine as well as decreased I-FABP levels in immunohistological staining of the intestine

Accumulation of advanced glycation end (AGEs) products in intensive care patients: an observational, prospective study

<p>Abstract</p> <p>Background</p> <p>Oxidative stress plays an important role in the course and eventual outcome in a majority of patients admitted to the intensive care unit (ICU). Markers to estimate oxidative stress are not readily available in a clinical setting. AGEs accumulation has been merely described in chronic conditions, but can also occur acutely due to oxidative stress. Since AGEs have emerged to be stable end products, these can be a marker of oxidative stress. Skin autofluorescence (AF) is a validated marker of tissue content of AGEs. We hypothesized that AGEs accumulate acutely in ICU patients.</p> <p>Methods</p> <p>We performed an observational prospective study in a medical surgical ICU in a university affiliated teaching hospital. All consecutively admitted ICU patients in a 2 month period were included. Skin AF was measured using an AGE reader in 35 consecutive ICU patients > 18 yrs. As a comparison, historical data of a control group (n = 231) were used. These were also used to calculate age-adjusted AF-levels (AF_adj). Values are expressed as median and interquartile range [P₂₅-P₇₅]. Differences between groups were tested by non parametric tests. P < 0.05 was considered statistically significant.</p> <p>Results</p> <p>AF_adjvalues were higher in ICU patients (0.33 [0.00 - 0.68]) than in controls (-0.07 [-0.29 - 0.24]; P < 0.001). No differences in skin AF_adjwere observed between acute or planned admissions, or presence of sepsis, nor was skin AF_adjrelated to severity of disease as estimated by APACHE-II score, length of ICU, hospital stay or mortality.</p> <p>Conclusion</p> <p>Acute AGE accumulation in ICU patients was shown in this study, although group size was small. This can possibly reflect oxidative stress in ICU patients. Further studies should reveal whether AGE-accumulation will be a useful parameter in ICU patients and whether skin AF has a predictive value for outcome, which was not shown in this small study.</p

Lokale Inflammation und ossäre Zell-Kommunikation nach Trauma : Untersuchungen im Klein-und Großtiermodell

Introduction: Based on the results of studies to date, it remains unclear whether concomitant injuries or fracture treatment techniques (osteosynthesis) have a significant effect on local inflammation after a severe trauma and thus cause complications of fracture healing in the form of pseudathroses. Therefore, this dissertation should investigate the specific influence of injuries and osteosynthesis techniques on the local inflammatory response in a clinically relevant polytrauma large animal model. In a second study, the effects of extracellular vesicles (EV) on fracture healing osteoblasts were investigated in a translational rat model, since EVs play a relevant role in the intercellular transport of inflammatory mediators and can thus influence their activity profile. Material and methods:The investigations in the large animal model included three groups: group monotrauma (isolated femur fracture), group polytrauma (femur fracture, thoracic trauma, liver laceration, hemorrhagic shock) and sham group (no trauma, only anesthesia/ventilation and catheterization). Depending on the group, the femur fracture was stabilized with an intramedullary nail or an external fixator. The total test duration was 72 h. Muscle and blood samples were taken at four time points (2, 24, 48 and 72 h post trauma) and cytokine concentration and expression as well as immune cell status were analyzed. Methods used were multiplex ELISAs, qRT-PCR and histological sections.In the rat model, a Krischner wire was first inserted intramedullary into the femur and then a femur fracture was induced by means of a blunt guillotine. Blood samples were collected after 3, 7 and 14 days and extracellular vesicles (EV) were isolated. Subsequently, primary osteoblasts were incubated with them and examined for viability and proliferation. In all approaches, EV-free plasma and plasma as a control were included. The analyses were performed by nanoparticle tracking analysis (NTA), immunohistological staining, newborn counts and a proliferation assay (MTT).Results:The comparison of the two supply strategies showed no significant difference for the local pro-inflammatory cytokine release in the musculature. However, intramedullary nailing in monotrauma compared to external fixation led to a significant IL-10 increase in muscle tissue (48 h after trauma, p< 0.05 and a significantly reduced infiltration of neutrophil granulocytes in adjacent muscle tissue (p = 0.041)). The fracture itself had a significant influence on the pro-inflammatory cytokine concentrations with significantly higher cytokine levels on the traumatized side (T-side) compared to the non-injured side (AT-side) (IL-6: 2 h p = 0.041, 24 h p = 0.0017; IL-8: 2 h p = 0.002, 24 h p = 0.029 and 48 h p = 0.008) in monotrauma. The severity of the overall trauma (mono- vs. polytrauma) also had a significant influence with increased local cytokine concentrations for monotrauma (2 h and 48 h mono- higher than polytrauma p = 0.003; p = 0.032). Furthermore, an increased immigration of neutrophil granulocytes into the muscle (mono vs. polytrauma 15.52 ± 5.39 vs. 8.23 ± 3.36 [neutrophil/visual field]; p = 0.013) after monotrauma was shown. After incubation with EV, primary osteoblasts took them up and processed them in the endoplamatic reticulum (ER). The results of the study shown here show that EV isolated from EV-free plasma contains molecules that promote the metabolism and proliferation of osteoblasts even over a long period of time after fracture. The full plasma used only showed a viability enhancing effect on osteoblasts after 14 days (p = 0.032), whereas EVs isolated from plasma significantly increased the viability of osteoblasts shortly after trauma induction and over a period of several days (3 d p = 0.038, 7 d p = 0.019 and 14 d p = 0.007). Discussion: Local inflammatory processes have a potential influence on fracture healing processes. In our study we were able to show that this local inflammatory reaction proceeds differently after polytrauma and monotrauma. The influence of the fracture treatment strategy also depends on the presence of mono- or polytrauma. Due to the systemic reaction in case of polytrauma, an inflammatory reaction comparable to the fracture side also occurs on the opposite side of the fracture. Furthermore, in polytrauma the supply strategy seems to play a subordinate role in the concentration of cytokines (IL-6, IL-8 and IL-10) in the muscle tissue on both the traumatized and non-traumatized side. Rather, it is influenced in particular by the concomitant injuries. A possible reason for this is the impaired activity of macrophages and neutrophilic granulocytes during trauma. In order to be able to evaluate the significance of care strategies in the context of a polytrauma in more detail, it is therefore necessary to identify more specific markers. The intramedullary nail reduces the number of locally recruited neutrophil granulocytes. In addition, pro-inflammatory (IL-6 and IL-8) cytokine transcription and anti-inflammatory (IL-10) protein concentration in muscle tissue close to the fracture are increased after monotrauma and treatment with an intramedullary nail. It could be postulated that due to the lack of concomitant injuries the recruitment of immune cells after monotrauma could be more targeted. The interaction between the inflammatory response and fracture (healing) could be significantly mediated by systemic EV, since the viability and proliferation of osteoblasts can be modified by EV. Due to this potential relevance of EV a potential use in the treatment of fracture healing disorders (e.g. pseudathrosis) is conceivable

Fracture healing and the underexposed role of extracellular vesicle-based crosstalk

The process of fracture healing is complex and requires an interaction of multiple organ systems. Cell-cell communication is known to be very important during this process. Extracellular vesicle (EVs) are small membranous vesicles generated from a variety of cells. Proteins, RNAs, small molecules and mitochondria DNA were found to be transported among cells through EVs. EV-based crosstalk represents a substantial cell-cell communication pattern, that can both interact with cells through molecular surfaces, and transfer molecules to cells. These interactions can assist in the synchronization of cellular functions among cells of the same kind, and coordinate the functions of different types of cells. After activation, platelets, neutrophils, macrophages, osteoblasts, osteoclasts, and mesenchymal stem cell (MSC) all secrete EVs, promoting the fracture healing process. Moreover, some studies have found evidence that EVs may be used for diagnosis and treatment of delayed fracture healing, and may be significantly involved in the pathophysiology of fracture healing disturbances. In this review, we summarize recent findings on: 1) EVs released by fracture healing-related cells, and 2) EV-mediated communications during fracture healing. We also highlight the potential applications of EVs in fracture healing. Lastly, the prospect of EVs for research and clinical use is discussed

Update on the role of endothelial cells in trauma

PURPOSE: This review gives an overview of physiological processes, mainly regarding vascular endothelial cells and their important role in hemostasis, information processing, and communication during trauma. An insight is given into molecules and cells involved in the first innate immune response through to the behavior of endothelial cells in developing trauma. The goal of this review is to show the overlap of crucial factors related to the endothelium and the development of trauma. METHODS: A systemic literature search was performed using Google scholar and PubMed. RESULTS: The results of the literature search showed that the endothelium, especially the vascular endothelium, is involved in various cellular and subcellular pathways of activation, suppression, and transfer of information. A variety of molecules and cells are orchestrated, subsequently the endothelium gets in contact with a traumatizing event. CONCLUSION: The endothelium is one of the first barriers that comes into contact with exo- and endogenous trauma-related signals and is a pivotal point in activating subsequent pathways and cascades by transfer of information

Trauma severity and its impact on local inflammation in extremity injury-insights from a combined trauma model in pigs

Background: Extremity fracture is frequently seen in multiple traumatized patients. Local post-traumatic inflammatory reactions as well as local and systemic interactions have been described in previous studies. However, trauma severity and its impact on the local immunologic reaction remains unclear. Therefore, fracture-associated local inflammation was investigated in a porcine model of isolated and combined trauma to gain information about the early inflammatory stages. Material and Methods: Polytrauma (PT) consisted of lung contusion, liver laceration, femur fracture, and controlled hemorrhage. Monotrauma (MT) consisted of femur fracture only. The fracture was operatively stabilized and animals were monitored under ICU-standard for 72 h. Blood, fracture hematoma (FH) as well as muscle samples were collected throughout the experimental period. Levels of local and systemic pro- and anti-inflammatory as well as angiogenetic cytokines were measured by ELISA. Results: Both groups showed a significant decrease in pro-inflammatory IL-6 in FH over time. However, concentrations in MT were significantly higher than in PT. The IL-8 concentrations initially decreased in FH, but recovered by the end of the observation period. These dynamics were only statistically significant in MT. Furthermore, concentrations measured in muscle tissue showed inverse kinetics compared to those in FH. The IL-10 did not present statistical resilient dynamics over time, although a slight increase in FH was seen by the end of the observation time in the MT group. Conclusions: Time-dependent dynamics of the local inflammatory response were observed. Trauma severity showed a significant impact, with lower values in pro- as well as angiogenetic mediators. Fracture repair could be altered by these trauma-related changes of the local immunologic milieu, which might serve as a possible explanation for the higher rates of delayed or non-union bone repair in polytraumatised patients

An Open-Source Object-Graph-Mapping Framework for Neo4j and Scala: Renesca

Part 2: Special Session on Privacy Aware Machine Learning for Health Data Science (PAML 2016)International audienceThe usage and application of graph databases is increasing. Many research problems are based on understanding relationships between data entities. This is where graph databases are powerful. Nevertheless, software developers model and think in object-oriented software. Combining both approaches leads to a paradigm mismatch. This mismatch can be addressed by using object graph mappers (OGM). OGM adapt graph databases for object-oriented code, to relieve the developer. Most graph database access frameworks only support table-based result outputs. This defeats one of the strongest purposes of using graph databases. In order to harness both the power of graph databases and object-oriented modeling (e.g. type-safety, inheritance, etc.) we propose an open-source framework with two libraries: (1) renesca, which is a graph database driver providing graph-query-results and change-tracking. (2) renesca-magic, a macro-based ER-modeling domain specific language (DSL). Both were tested in a graph-based application and lead to dramatic improvements in code size (factor 10) and extensibility of the code, with no significant effect on performance