LINE-1 RNA triggers matrix formation in bone cells via a PKR-mediated inflammatory response.

Transposable elements (TEs) are mobile genetic modules of viral derivation that have been co-opted to become modulators of mammalian gene expression. TEs are a major source of endogenous dsRNAs, signaling molecules able to coordinate inflammatory responses in various physiological processes. Here, we provide evidence for a positive involvement of TEs in inflammation-driven bone repair and mineralization. In newly fractured mice bone, we observed an early transient upregulation of repeats occurring concurrently with the initiation of the inflammatory stage. In human bone biopsies, analysis revealed a significant correlation between repeats expression, mechanical stress and bone mineral density. We investigated a potential link between LINE-1 (L1) expression and bone mineralization by delivering a synthetic L1 RNA to osteoporotic patient-derived mesenchymal stem cells and observed a dsRNA-triggered protein kinase (PKR)-mediated stress response that led to strongly increased mineralization. This response was associated with a strong and transient inflammation, accompanied by a global translation attenuation induced by eIF2α phosphorylation. We demonstrated that L1 transfection reshaped the secretory profile of osteoblasts, triggering a paracrine activity that stimulated the mineralization of recipient cells.

Murine iPSC-Loaded Scaffold Grafts Improve Bone Regeneration in Critical-Size Bone Defects.

In certain situations, bones do not heal completely after fracturing. One of these situations is a critical-size bone defect where the bone cannot heal spontaneously. In such a case, complex fracture treatment over a long period of time is required, which carries a relevant risk of complications. The common methods used, such as autologous and allogeneic grafts, do not always lead to successful treatment results. Current approaches to increasing bone formation to bridge the gap include the application of stem cells on the fracture side. While most studies investigated the use of mesenchymal stromal cells, less evidence exists about induced pluripotent stem cells (iPSC). In this study, we investigated the potential of mouse iPSC-loaded scaffolds and decellularized scaffolds containing extracellular matrix from iPSCs for treating critical-size bone defects in a mouse model. In vitro differentiation followed by Alizarin Red staining and quantitative reverse transcription polymerase chain reaction confirmed the osteogenic differentiation potential of the iPSCs lines. Subsequently, an in vivo trial using a mouse model (n = 12) for critical-size bone defect was conducted, in which a PLGA/aCaP osteoconductive scaffold was transplanted into the bone defect for 9 weeks. Three groups (each n = 4) were defined as (1) osteoconductive scaffold only (control), (2) iPSC-derived extracellular matrix seeded on a scaffold and (3) iPSC seeded on a scaffold. Micro-CT and histological analysis show that iPSCs grafted onto an osteoconductive scaffold followed by induction of osteogenic differentiation resulted in significantly higher bone volume 9 weeks after implantation than an osteoconductive scaffold alone. Transplantation of iPSC-seeded PLGA/aCaP scaffolds may improve bone regeneration in critical-size bone defects in mice.

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, TCA-cycle intermediates are increasingly identified as promising makers for cellular ischemia and mitochondrial dysfunction during hemorrhagic shock (HS). 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 HS. METHODS: 52 male pigs (50 ± 5 kg) were randomized into two groups: Group IF (isolated fracture) was subject to a standardized femur shaft fracture. Group PT (polytrauma) was subject to a femur fracture, followed by blunt chest trauma, liver laceration and a pressure controlled hemorrhagic shock for 60 min. Resuscitation was performed with crystalloids. Fractures were stabilized by intramedullary nailing. Venous samples were collected at 6 timepoints (baseline, trauma, resuscitation, 2 h, 4 h and 6 h). Lipidomic analysis was performed via liquid chromatography coupled mass spectrometry. Measurements were collated with clinical markers and near-infrared spectrometry measurements (NIRS) 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) two-fold increase after HS in Group PT 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 HS. The more rapid normalization after resuscitation in comparison to acid base changes may warrant further investigation. STUDY TYPE: Experimental Animal Model. LEVEL OF EVIDENCE: N/A.

PRAMEL7 and CUL2 decrease NuRD stability to establish ground-state pluripotency.

Pluripotency is established in E4.5 preimplantation epiblast. Embryonic stem cells (ESCs) represent the immortalization of pluripotency, however, their gene expression signature only partially resembles that of developmental ground-state. Induced PRAMEL7 expression, a protein highly expressed in the ICM but lowly expressed in ESCs, reprograms developmentally advanced ESC+serum into ground-state pluripotency by inducing a gene expression signature close to developmental ground-state. However, how PRAMEL7 reprograms gene expression remains elusive. Here we show that PRAMEL7 associates with Cullin2 (CUL2) and this interaction is required to establish ground-state gene expression. PRAMEL7 recruits CUL2 to chromatin and targets regulators of repressive chromatin, including the NuRD complex, for proteasomal degradation. PRAMEL7 antagonizes NuRD-mediated repression of genes implicated in pluripotency by decreasing NuRD stability and promoter association in a CUL2-dependent manner. Our data link proteasome degradation pathways to ground-state gene expression, offering insights to generate in vitro models to reproduce the in vivo ground-state pluripotency.

Computational structure-based approach to study chimeric antigens using a new protein scaffold displaying foreign epitopes.

The identification and recombinant production of functional antigens and/or epitopes of pathogens represent a crucial step for the development of an effective protein-based vaccine. Many vaccine targets are outer membrane proteins anchored into the lipidic bilayer through an extended hydrophobic portion making their recombinant production challenging. Moreover, only the extracellular loops, and not the hydrophobic regions, are naturally exposed to the immune system. In this work, the Domain 3 (D3) from Group B Streptococcus (GBS) pilus 2a backbone protein has been identified and engineered to be used as a scaffold for the display of extracellular loops of two Neisseria gonorrhoeae membrane proteins (PorB.1b and OpaB). A computational structure-based approach has been applied to the design of both the scaffold and the model antigens. Once identified the best D3 engineerable site, several different chimeric D3 displaying PorB.1b and OpaB extracellular loops were produced as soluble proteins. Each molecule has been characterized in terms of solubility, stability, and ability to correctly display the foreign epitope. This antigen dissection strategy allowed the identification of most immunogenic extracellular loops of both PorB.1b and OpaB gonococcal antigens. The crystal structure of chimeric D3 displaying PorB.1b immunodominant loop has been obtained confirming that the engineerization did not alter the predicted native structure of this epitope. Taken together, the reported data suggest that D3 is a novel protein scaffold for epitope insertion and display, and a valid alternative to the production of whole membrane protein antigens. Finally, this work describes a generalized computational structure-based approach for the identification, design, and dissection of epitopes in target antigens through chimeric proteins.

Impact of a High-Fat Diet at a Young Age on Wound Healing in Mice.

As the prevalence of juvenile-onset obesity rises globally, the multitude of related health consequences gain significant importance. In this context, obesity is associated with impaired cutaneous wound healing. In experimental settings, mice are the most frequently used model for investigating the effect of high-fat diet (HFD) chow on wound healing in wild-type or genetically manipulated animals, e.g., diabetic ob/ob and db/db mice. However, these studies have mainly been performed on adult animals. Thus, in the present study, we introduced a mouse model for a juvenile onset of obesity. We exposed 4-week-old mice to an investigational feeding period of 9 weeks with an HFD compared to a regular diet (RD). At a mouse age of 13 weeks, we performed excisional and incisional wounding and measured the healing rate. Wound healing was examined by serial photographs with daily wound size measurements of the excisional wounds. Histology from incisional wounds was performed to quantify granulation tissue (thickness, quality) and angiogenesis (number of blood vessels per mm2). The expression of extracellular matrix proteins (collagen types I/III/IV, fibronectin 1, elastin), inflammatory cytokines (MIF, MIF-2, IL-6, TNF-α), myofibroblast differentiation (α-SMA) and macrophage polarization (CD11c, CD301b) in the incisional wounds were evaluated by RT-qPCR and by immunohistochemistry. There was a marked delay of wound closure in the HFD group with a decrease in granulation tissue quality and thickness. Additionally, inflammatory cytokines (MIF, IL-6, TNF-α) were significantly up-regulated in HFD- when compared to RD-fed mice measured at day 3. By contrast, MIF-2 and blood vessel expression were significantly reduced in the HFD animals, starting at day 1. No significant changes were observed in macrophage polarization, collagen expression, and levels of TGF-ß1 and PDGF-A. Our findings support that an early exposition to HFD resulted in juvenile obesity in mice with impaired wound repair mechanisms, which may be used as a murine model for obesity-related studies in the future.

Proof of concept for a single-dose Group B Streptococcus vaccine based on capsular polysaccharide conjugated to Qß virus-like particles.

A maternal vaccine to protect neonates against Group B Streptococcus invasive infection is an unmet medical need. Such a vaccine should ideally be offered during the third trimester of pregnancy and induce strong immune responses after a single dose to maximize the time for placental transfer of protective antibodies. A key target antigen is the capsular polysaccharide, an anti-phagocytic virulence factor that elicits protective antibodies when conjugated to carrier proteins. The most prevalent polysaccharide serotypes conjugated to tetanus or diphtheria toxoids have been tested in humans as monovalent and multivalent formulations, showing excellent safety profiles and immunogenicity. However, responses were suboptimal in unprimed individuals after a single shot, the ideal schedule for vaccination during the third trimester of pregnancy. In the present study, we obtained and optimized self-assembling virus-like particles conjugated to Group B Streptococcus capsular polysaccharides. The resulting glyco-nanoparticles elicited strong immune responses in mice already after one immunization, providing pre-clinical proof of concept for a single-dose vaccine.

The spinal cord injury-induced immune deficiency syndrome: results of the SCIentinel study.

Infections are prevalent after spinal cord injury (SCI), constitute the main cause of death and are a rehabilitation confounder associated with impaired recovery. We hypothesize that SCI causes an acquired lesion-dependent (neurogenic) immune suppression as an underlying mechanism to facilitate infections. The international prospective multicentre cohort study (SCIentinel; protocol registration DRKS00000122; n = 111 patients) was designed to distinguish neurogenic from general trauma-related effects on the immune system. Therefore, SCI patient groups differing by neurological level, i.e. high SCI [thoracic (Th)4 or higher]; low SCI (Th5 or lower) and severity (complete SCI; incomplete SCI), were compared with a reference group of vertebral fracture (VF) patients without SCI. The primary outcome was quantitative monocytic Human Leukocyte Antigen-DR expression (mHLA-DR, synonym MHC II), a validated marker for immune suppression in critically ill patients associated with infection susceptibility. mHLA-DR was assessed from Day 1 to 10 weeks after injury by applying standardized flow cytometry procedures. Secondary outcomes were leucocyte subpopulation counts, serum immunoglobulin levels and clinically defined infections. Linear mixed models with multiple imputation were applied to evaluate group differences of logarithmic-transformed parameters. Mean quantitative mHLA-DR [ln (antibodies/cell)] levels at the primary end point 84 h after injury indicated an immune suppressive state below the normative values of 9.62 in all groups, which further differed in its dimension by neurological level: high SCI [8.95 (98.3% confidence interval, CI: 8.63; 9.26), n = 41], low SCI [9.05 (98.3% CI: 8.73; 9.36), n = 29], and VF without SCI [9.25 (98.3% CI: 8.97; 9.53), n = 41, P = 0.003]. Post hoc analysis accounting for SCI severity revealed the strongest mHLA-DR decrease [8.79 (95% CI: 8.50; 9.08)] in the complete, high SCI group, further demonstrating delayed mHLA-DR recovery [9.08 (95% CI: 8.82; 9.38)] and showing a difference from the VF controls of -0.43 (95% CI: -0.66; -0.20) at 14 days. Complete, high SCI patients also revealed constantly lower serum immunoglobulin G [-0.27 (95% CI: -0.45; -0.10)] and immunoglobulin A [-0.25 (95% CI: -0.49; -0.01)] levels [ln (g/l × 1000)] up to 10 weeks after injury. Low mHLA-DR levels in the range of borderline immunoparalysis (below 9.21) were positively associated with the occurrence and earlier onset of infections, which is consistent with results from studies on stroke or major surgery. Spinal cord injured patients can acquire a secondary, neurogenic immune deficiency syndrome characterized by reduced mHLA-DR expression and relative hypogammaglobulinaemia (combined cellular and humoral immune deficiency). mHLA-DR expression provides a basis to stratify infection-risk in patients with SCI.

Lesional Antibody Synthesis and Complement Deposition Associate With De Novo Antineuronal Antibody Synthesis After Spinal Cord Injury.

BACKGROUND AND OBJECTIVES: Spinal cord injury (SCI) disrupts the fine-balanced interaction between the CNS and immune system and can cause maladaptive aberrant immune responses. The study examines emerging autoantibody synthesis after SCI with binding to conformational spinal cord epitopes and surface peptides located on the intact neuronal membrane. METHODS: This is a prospective longitudinal cohort study conducted in acute care and inpatient rehabilitation centers in conjunction with a neuropathologic case-control study in archival tissue samples ranging from acute injury (baseline) to several months thereafter (follow-up). In the cohort study, serum autoantibody binding was examined in a blinded manner using tissue-based assays (TBAs) and dorsal root ganglia (DRG) neuronal cultures. Groups with traumatic motor complete SCI vs motor incomplete SCI vs isolated vertebral fracture without SCI (controls) were compared. In the neuropathologic study, B cell infiltration and antibody synthesis at the spinal lesion site were examined by comparing SCI with neuropathologically unaltered cord tissue. In addition, the CSF in an individual patient was explored. RESULTS: Emerging autoantibody binding in both TBA and DRG assessments was restricted to an SCI patient subpopulation only (16%, 9/55 sera) while being absent in vertebral fracture controls (0%, 0/19 sera). Autoantibody binding to the spinal cord characteristically detected the substantia gelatinosa, a less-myelinated region of high synaptic density involved in sensory-motor integration and pain processing. Autoantibody binding was most frequent after motor complete SCI (grade American Spinal Injury Association impairment scale A/B, 22%, 8/37 sera) and was associated with neuropathic pain medication. In conjunction, the neuropathologic study demonstrated lesional spinal infiltration of B cells (CD20, CD79a) in 27% (6/22) of patients with SCI, the presence of plasma cells (CD138) in 9% (2/22). IgG and IgM antibody syntheses colocalized to areas of activated complement (C9neo) deposition. Longitudinal CSF analysis of an additional single patient demonstrated de novo (IgM) intrathecal antibody synthesis emerging with late reopening of the blood-spinal cord barrier. DISCUSSION: This study provides immunologic, neurobiological, and neuropathologic proof-of-principle for an antibody-mediated autoimmunity response emerging approximately 3 weeks after SCI in a patient subpopulation with a high demand of neuropathic pain medication. Emerging autoimmunity directed against specific spinal cord and neuronal epitopes suggests the existence of paratraumatic CNS autoimmune syndromes.

SAXS imaging reveals optimized osseointegration properties of bioengineered oriented 3D-PLGA/aCaP scaffolds in a critical size bone defect model.

Healing large bone defects remains challenging in orthopedic surgery and is often associated with poor outcomes and complications. A major issue with bioengineered constructs is achieving a continuous interface between host bone and graft to enhance biological processes and mechanical stability. In this study, we have developed a new bioengineering strategy to produce oriented biocompatible 3D PLGA/aCaP nanocomposites with enhanced osseointegration. Decellularized scaffolds -containing only extracellular matrix- or scaffolds seeded with adipose-derived mesenchymal stromal cells were tested in a mouse model for critical size bone defects. In parallel to micro-CT analysis, SAXS tensor tomography and 2D scanning SAXS were employed to determine the 3D arrangement and nanostructure within the critical-sized bone. Both newly developed scaffold types, seeded with cells or decellularized, showed high osseointegration, higher bone quality, increased alignment of collagen fibers and optimal alignment and size of hydroxyapatite minerals.

Post-traumatic growth in polytraumatized patients after 20+ years: a long-term follow-up study of 337 patients treated at a level 1 trauma center.

PURPOSE: There is limited research on the long-term psychiatric outcomes of polytraumatized patients. Existing studies focus mainly on the negative sequelae. Post-traumatic growth (PTG) describes positive personal development after severe physical or mental distress. In this study, we investigated post-traumatic growth in polytraumatized patients at least 20 years after trauma. METHODS: Patients treated for polytrauma at a German level 1 trauma center between 1971 and 1990, were contacted 20+ years later. A questionnaire with 37 questions from the stress-related growth scale (SRGS) and the post-traumatic growth inventory (PGI) was administered. PTG was quantified in five specific areas. PTG and patient demographics were then analyzed using logistic regression. RESULTS: Eligible questionnaires were returned by 337 patients. 96.5% of patients reported improvements regarding at least one of the 37 questions. Approximately, a third of patients noticed distinct improvements regarding their relationship to others (29.2%), appreciation of life (36.2%) and attitudes towards new possibilities (32.5%). Patient demographics were significant predictors for the development of PTG: Older (p < 0.001), female (p = 0.042) and married patients (p = 0.047) showed a greater expression of PTG. We also saw significantly more PTG in patients with higher injury severity (p = 0.033). CONCLUSION: 20 years after polytrauma, patients report improvements in their relationship with others, appreciation of life and attitude towards new possibilities. Women and married patients show higher expression of PTG. Furthermore, there is higher expression of PTG with higher age and injury severity. Post-traumatic growth should be identified and fostered in clinical practice. LEVEL OF EVIDENCE: III-prospective long-term follow-up study.

Self-assembling protein nanoparticles and virus like particles correctly display ß-barrel from meningococcal factor H-binding protein through genetic fusion.

Recombinant protein-based vaccines are a valid and safer alternative to traditional vaccines based on live-attenuated or killed pathogens. However, the immune response of subunit vaccines is generally lower compared to that elicited by traditional vaccines and usually requires the use of adjuvants. The use of self-assembling protein nanoparticles, as a platform for vaccine antigen presentation, is emerging as a promising approach to enhance the production of protective and functional antibodies. In this work we demonstrated the successful repetitive antigen display of the C-terminal ß-barrel domain of factor H binding protein, derived from serogroup B Meningococcus on the surface of different self-assembling nanoparticles using genetic fusion. Six nanoparticle scaffolds were tested, including virus-like particles with different sizes, geometries, and physicochemical properties. Combining computational and structure-based rational design we were able generate antigen-fused scaffolds that closely aligned with three-dimensional structure predictions. The chimeric nanoparticles were produced as recombinant proteins in Escherichia coli and evaluated for solubility, stability, self-assembly, and antigen accessibility using a variety of biophysical methods. Several scaffolds were identified as being suitable for genetic fusion with the ß-barrel from fHbp, including ferritin, a de novo designed aldolase from Thermotoga maritima, encapsulin, CP3 phage coat protein, and the Hepatitis B core antigen. In conclusion, a systematic screening of self-assembling nanoparticles has been applied for the repetitive surface display of a vaccine antigen. This work demonstrates the capacity of rational structure-based design to develop new chimeric nanoparticles and describes a strategy that can be utilized to discover new nanoparticle-based approaches in the search for vaccines against bacterial pathogens.

Effects of Occult Hypoperfusion on Local Circulation and Inflammation - An Analysis in a Standardized Polytrauma Model.

Introduction: Occult hypoperfusion (OH) is defined as persistent lactic acidosis despite normalization of vital parameters following trauma. The aim of this study was to analyze the association of occult hypoperfusion with local circulation and inflammation of injured soft tissue in a porcine polytrauma model. Methods: This experimental study was performed with male landrace pigs who suffered a standardized polytrauma, including a femoral fracture, blunt chest trauma, liver laceration and a mean arterial pressure (MAP) controlled hemorrhagic shock. One hour after induction of trauma, the animals were resuscitated with retrograde femoral nailing, liver packing and volume replacement. Animals were stratified into Group Norm (normalizing lactate levels after resuscitation) and Group occult hypoperfusion (OH) (persistent lactate levels above 2 mmol/l with normalizing vital parameters after resuscitation). Local circulation (oxygen saturation, hemoglobin amount, blood flow) was measured with optical sensors at the subcutaneous soft tissue at the fractured extremity as well as at the stomach and colon. Local inflammatory parameters [interleukin (IL) 6, 8, 10, and heat shock protein (HSP)] were analyzed in the subcutaneous tissue of the fractured extremity. Results: Group Norm (n = 19) and Group OH (n = 5) were comparable in baseline vital and laboratory parameters. The shock severity and total amount of blood loss were comparable among Group Norm and Group OH. Following resuscitation Group OH had significantly lower local relative hemoglobin amount at the injured soft tissue of the fractured extremity when compared with Group Norm (39.4, SD 5.3 vs. 63.9, SD 27.6 A.U., p = 0.031). The local oxygenation was significantly lower in Group OH compared to Group Norm (60.4, SD 4.6 vs. 75.8, SD 12.8, p = 0.049). Local IL-6 in the fatty tissue was significantly higher in Group OH (318.3, SD 326.6 [pg/ml]) when compared with Group Norm (73.9,SD 96.3[pg/ml], p = 0.03). The local circulation at the abdominal organs was comparable in both groups. Conclusion: OH is associated with decreased local circulation and increased local inflammation at the injured soft tissue of the extremity in polytrauma. OH might reflect the severity of local soft tissue injuries, and guide treatment strategies.

Occult hypoperfusion and changes of systemic lipid levels after severe trauma: an analysis in a standardized porcine polytrauma model.

BACKGROUND: Occult hypoperfusion describes the absence of sufficient microcirculation despite normal vital signs. It is known to be associated with prolonged elevation of serum lactate and later complications in severely injured patients. We hypothesized that changes in circulating lipids are related to responsiveness to resuscitation. The purpose of this study is investigating the relation between responsiveness to resuscitation and lipidomic course after poly trauma. METHODS: Twenty-five male pigs were exposed a combined injury of blunt chest trauma, liver laceration, controlled haemorrhagic shock, and femoral shaft fracture. After 1 h, animals received resuscitation and fracture stabilization. Venous blood was taken regularly and 233 specific lipids were analysed. Animals were divided into two groups based on serum lactate level at the end point as an indicator of responsiveness to resuscitation (<2 mmol/L: responder group (R group), ≧2 mmol/L: occult hypoperfusion group (OH group)). RESULTS: Eighteen animals met criteria for the R group, four animals for the OH group, and three animals died. Acylcarnitines showed a significant increase at 1 h compared to baseline in both groups. Six lipid subgroups showed a significant increase only in R group at 2 h. There was no significant change at other time points. CONCLUSIONS: Six lipid groups increased significantly only in the R group at 2 h, which may support the idea that they could serve as potential biomarkers to help us to detect the presence of occult hypoperfusion and insufficient resuscitation. We feel that further study is required to confirm the role and mechanism of lipid changes after trauma.

Healing after Trauma-New Knowledge and Procedures for the Benefit of Our Patients.

Severe trauma is still the leading cause of death and disability in the world [...].

Assessment of alternative techniques to quantify the effect of injury on soft tissue in closed ankle and pilon fractures.

INTRODUCTION: Local soft tissue status (STS) guides the timing for definitive surgical treatment strategies of fracture fixation around the ankle joint. The aim of this study was to assess different types of new technical devices in relation to the surgical treatment in closed ankle and pilon fractures. METHODS: This study was designed as a cohort study. Adult patients admitted between February 1, 2019 and December 31, 2020 presenting with closed ankle fracture requiring surgical treatment were eligible. The exclusion criteria were previous injuries to the lower extremity, acute deep venous thrombosis, skin diseases, and delayed presentation (admission >24 hours after injury). Moderate-energy trauma includes injuries sustained during team sports, biking, and running. The primary outcome was the assessment of the degree of soft tissue involvement following closed fractures by comparing different techniques focusing on the ankle region and including ankle and pilon fractures. The variables of interest included the circumference of soft tissue swelling around the ankle, determined within a 5-mm range in the area of the medial and lateral malleolus and the bone-skin distance on a plain radiograph, determined by the largest distance from the malleolus to the border of the soft-tissue shadow. STS assessment included optical measures of local perfusion (O2C, Lea Inc. Germany) and tactile measures of mechanical characteristics (Myoton® tensiometer AS, Estonia). Measurements of Group Temp (temporary stabilization) and Group Def (definitive surgery) were taken on admission and prior to the treatment strategy decision. The contralateral non-injured ankle served as a control. The quality of assessment tools was quantified by calculating the smallest detectable change (SDC). RESULTS: In total, 38 patients with a mean age of 40.4 (SD 17.8) years were included. The SDC was 3.2% (95%CI 2.5 to 3.8) for local blood flow and 1.1% (95%CI 0.4 to 1.7) for soft tissue stiffness. The circumference of the injured area at admission was significantly higher than that of the healthy site (28.2 [SD 3.4] cm versus 23.9 [SD 2.4] cm, p < 0.001). The local perfusion (blood flow 107.5 (SD 40.79 A.U. vs. 80.1 [SD 13.8] A.U., p = 0.009), and local dynamic stiffness of the skin (668.1 (SD 148.0) N/m vs 449.5 (SD 87.7) N/m, p < 0.001) were significantly higher at the injured site. In Group Temp, the local blood flow was significantly higher when compared with Group Def (109.6 [SD 39.8] vs. 94.5 [SD 13.0], p = 0.023). The dynamic stiffness of the soft tissue was significantly higher in Group Temp (679.4 N/m [SD 147.0] N/m vs. 573.0 N/m (SD 93.8) N/m, p < 0.001). The physical properties of STS were comparable among the fracture types. None of the included patients had local soft tissue complications. CONCLUSION: Closed fractures of the ankle and the pilon are associated with an increase in local circulation and local soft tissue stiffness and tension. These changes of the STS following injury can be quantified in a standardized and reproducible manner.

Thioflavin-modified molecularly imprinted hydrogel for fluorescent-based non-enzymatic glucose detection in wound exudate.

The concentration of glucose in the body's fluids is an important parameter that can indicate pathological conditions such as the progress of infected wounds. Several wearables and implantable detection approaches have been developed with high selectivity and sensitivity for glucose. However, all of them have drawbacks such as low stability, limited selectivity, and often require complex technology. In this work, we present a fluorescent-based cost-efficient imprinted hydrogel (MIH_GSH) capable of detecting glucose within 30 â€‹min. The imprinting approach allows us to improve the selectivity for glucose, overcoming the low specificity and limited binding efficiency at neutral pH of boronic acid-based detection mechanisms. The binding affinity determined for glucose-MIH_GSH was indeed 6-fold higher than the one determined for the non-imprinted hydrogel with a calculated imprinting factor of 1.7. The limit of detection of MIH_GSH for glucose in artificial wound exudate was calculated as 0.48 â€‹mM at pH 7.4 proving the suitability of the proposed approach to diagnose chronic wounds (ca. 1 â€‹mM). MIH_GSH was compared with a commercial colorimetric assay for the quantification of glucose in wound exudate specimens collected from hospitalized patients. The results obtained with the two methods were statistically similar confirming the robustness of our approach. Importantly, whereas with the colorimetric assay sample preparation was required to limit the interference of the sample background, the fluorescent signal of MIH_GSH was not affected even when used to measure glucose directly in bloody samples. The sensing mechanism here proposed can pave the way for the development of cost-efficient and wearable point-of-care tools capable of monitoring the glucose level in wound exudate enabling the quick assessment of chronic injuries.

The local soft tissue status and the prediction of local complications following fractures of the ankle region.

INTRODUCTION: Well-known risk factors (RF) for soft tissue complications following surgical treatment of fracture of the ankle region include diabetes, smoking, and the local soft tissue status. A weighted analysis might provide a risk profile that guides the surgical treatment strategy. The aim of this meta-analysis was to provide a risk profile for soft tissue complications following closed fractures of the ankle region. METHODS: This review provides a meta-analysis of studies that investigate potential risk factors for complications in fractures of the ankle region. INCLUSION CRITERIA: Original articles that were published between 2000 and 2020 in English or German language that calculated odds ratios (OR) of RF for soft tissue complications. Further, this study only includes articles that investigated fractures of the ankle region including pilon fracture, calcaneal fractures, and fractures of the malleoli. This study excluded articles that provide exploratory analyses, narrative reviews, and case reports. RF were stratified as patient specific systemic RF (PSS), patient specific local RF (PSL), and non-patient specific RF (NPS). PSS RF includes comorbidities, American society of anaesthesiology (ASA), requirement of medication, additional injuries, and smoking or substance abuse. PSL RF includes soft tissue status, wounds, and associated complications. NPS RF includes duration of surgery, staged procedure, or time to definitive surgery. Random effect (RE) models were utilized to summarize the effect measure (OR) for each group or specific RF. RESULTS: Out of 1352 unique articles, 34 were included for quantitative analyses. Out of 370 complications, the most commonly assessed RF were comorbidities (34.6%). Local soft tissue status accounted for 7.5% of all complications. The overall rate for complication was 10.9% (standard deviation, SD 8.7%). PSS RF had an OR of 1.04 (95%CI 1.01 to 1.06, p = 0.006), PSL an OR of 1.79 (95% 1.28 to 2.49, p = 0.0006), and NPS RF an OR of 1.01 (95%CI 0.97 to 1.05, p = 0.595). Additional injuries did not predict complications (OR 1.23, 95%CI 0.44 to 3.45, p = 0.516). The most predictive RF were open fracture (OR 3.47, 95%CI 1.64 to 7.34, p < 0.001), followed by local tissue damage (OR 3.05, 95%CI 1.23 to 40.92, p = 0.04), and diabetes (OR 2.3, 95%CI 1.1 to 4.79, p = 0.26). CONCLUSION: Among all RFs for regional soft tissue complications, the most predictive is the local soft tissue status, while additional injuries or NPS RF were less predictive. The soft tissue damage can be quantified and outweighs the cofactors described in previous publications. The soft tissue status appears to have a more important role in the decision making of the treatment strategy when compared with comorbidities such as diabetes.

Cellular activation status in femoral shaft fracture hematoma following different reaming techniques - A large animal model.

The local inflammatory impact of different reaming protocols in intramedullary nailing has been sparsely investigated. We examined the effect of different reaming protocols on fracture hematoma (FH) immunological characteristics in pigs. To do so, a standardized midshaft femur fracture was induced in adult male pigs. Fractures were treated with conventional reamed femoral nailing (group RFN, n = 6); unreamed femoral nailing (group UFN, n = 6); reaming with a Reamer Irrigator Aspirator device (group RIA, n = 12). Animals were observed for 6 h and FH was collected. FH-cell apoptosis and neutrophil receptor expression (Mac-1/CD11b and FcγRIII/CD16) were studied by flow cytometry and local temperature changes were analyzed. The study demonstrates that apoptosis-rates of FH-immune cells were significantly lower in group RIA (3.50 ± 0.53%) when compared with non-RIA groups: (group UFN 12.50 ± 5.22%, p = 0.028 UFN vs. RIA), (group RFN 13.30 ± 3.18%, p < 0.001, RFN vs. RIA). Further, RIA-FH showed lower neutrophil CD11b/CD16 expression when compared with RFN (mean difference of 43.0% median fluorescence intensity (MFI), p = 0.02; and mean difference of 35.3% MFI, p = 0.04, respectively). Finally, RIA induced a transient local hypothermia and hypothermia negatively correlated with both FH-immune cell apoptosis and neutrophil activation. In conclusion, immunologic changes observed in FH appear to be modified by certain reaming techniques. Irrigation during reaming was associated with transient local hypothermia, decreased apoptosis, and reduced neutrophil activation. Further study is warranted to examine whether the rinsing effect of RIA, specific tissue removal by reaming, or thermal effects predominantly determine local inflammatory changes during reaming.