The effect of the pro-inflammatory cytokine tumor necrosis factor-alpha on human joint capsule myofibroblasts

Introduction: Previous studies have shown that the number of myoblastically differentiated fibroblasts known as myofibroblasts (MFs) is significantly increased in stiff joint capsules, indicating their crucial role in the pathogenesis of post-traumatic joint stiffness. Although the mode of MFs' function has been well defined for different diseases associated with tissue fibrosis, the underlying mechanisms of their regulation in the pathogenesis of post-traumatic joint capsule contracture are largely unknown. Methods: In this study, we examined the impact of the pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) on cellular functions of human joint capsule MFs. MFs were challenged with different concentrations of TNF-alpha with or without both its specifically inactivating antibody infliximab (IFX) and cyclooxygenase-2 (COX2) inhibitor diclofenac. Cell proliferation, gene expression of both alpha-smooth muscle actin (alpha-SMA) and collagen type I, the synthesis of prostaglandin derivates E(2), F(1A), and F(2A), as well as the ability to contract the extracellular matrix were assayed in monolayers and in a three-dimensional collagen gel contraction model. The a-SMA and COX2 protein expressions were evaluated by immunofluorescence staining and Western blot analysis. Results: The results indicate that TNF-alpha promotes cell viability and proliferation of MFs, but significantly inhibits the contraction of the extracellular matrix in a dose-dependent manner. This effect was associated with downregulation of a-SMA and collagen type I by TNF-alpha application. Furthermore, we found a significant time-dependent upregulation of prostaglandin E(2) synthesis upon TNF-alpha treatment. The effect of TNF-alpha on COX2-positive MFs could be specifically prevented by IFX and partially reduced by the COX2 inhibitor diclofenac. Conclusions: Our results provide evidence that TNF-alpha specifically modulates the function of MFs through regulation of prostaglandin E(2) synthesis and therefore may play a crucial role in the pathogenesis of joint capsule contractures

Exposure to radial extracorporeal shock waves modulates viability and gene expression of human skeletal muscle cells: a controlled in vitro study

Background: Recent clinical and animal studies have shown that extracorporeal shock wave therapy has a promoting influence on the healing process of musculoskeletal disorders. However, the underlying biological effects of extracorporeal shock wave therapy on human skeletal muscle cells have not yet been investigated. Methods: In this study, we investigated human skeletal muscle cells after exposure to radial extracorporeal shock waves in a standardized in vitro setup. Cells were isolated from muscle specimens taken from adult patients undergoing spine surgery. Primary muscle cells were exposed once or twice to radial extracorporeal shock waves in vitro with different energy flux densities. Cell viability and gene expression of the paired box protein 7 (Pax7), neural cell adhesion molecule (NCAM), and myogenic factor 5 (Myf5) and MyoD as muscle cell markers were compared to non-treated muscle cells that served as controls. Results: Isolated muscle cells were positive for the hallmark protein of satellite cells, Pax7, as well as for the muscle cell markers NCAM, MyoD, and Myf5. Exposure to radial extracorporeal shock waves at low energy flux densities enhanced cell viability, whereas higher energy flux densities had no further significant impact. Gene expression analyses of muscle specific genes (Pax7, NCAM, Myf5, and MyoD) demonstrated a significant increase after single exposure to the highest EFD (4 bar, 0.19 mJ/mm(2)) and after double exposure with the medium EFDs (2 and 3 bar;0.09 and 0.14 mJ/mm(2), respectively). Double exposure of the highest EFD, however, results in a significant down-regulation when compared to single exposure with this EFD. Conclusions: This is the first study demonstrating that radial extracorporal shock wave therapy has the potential to modulate the biological function of human skeletal muscle cells. Based on our experimental findings, we hypothesize that radial extracorporal shock wave therapy could be a promising therapeutic modality to improve the healing process of sports-related structural muscle injuries

Dexamethasone Inhibits the Pro-Angiogenic Potential of Primary Human Myoblasts

Tissue regeneration depends on the complex processes of angiogenesis, inflammation and wound healing. Regarding muscle tissue, glucocorticoids (GCs) inhibit pro-inflammatory signalling and angiogenesis and lead to muscle atrophy. Our hypothesis is that the synthetic GC dexamethasone (dex) impairs angiogenesis leading to muscle atrophy or inhibited muscle regeneration. Therefore, this study aims to elucidate the effect of dexamethasone on HUVECs under different conditions in mono- and co-culture with myoblasts to evaluate growth behavior and dex impact with regard to muscle atrophy and muscle regeneration. Viability assays, qPCR, immunofluorescence as well as ELISAs were performed on HUVECs, and human primary myoblasts seeded under different culture conditions. Our results show that dex had a higher impact on the tube formation when HUVECs were maintained with VEGF. Gene expression was not influenced by dex and was independent of cells growing in a 2D or 3D matrix. In co-culture CD31 expression was suppressed after incubation with dex and gene expression analysis revealed that dex enhanced expression of myogenic transcription factors, but repressed angiogenic factors. Moreover, dex inhibited the VEGF mediated pro angiogenic effect of myoblasts and inhibited expression of angiogenic inducers in the co-culture model. This is the first study describing a co-culture of human primary myoblast and HUVECs maintained under different conditions. Our results indicate that dex affects angiogenesis via inhibition of VEGF release at least in myoblasts, which could be responsible not only for the development of muscle atrophy after dex administration, but also for inhibition of muscle regeneration after vascular damage

Bilateral Pseudarthrosis of the Femoral Neck in a 25-Year-Old Male with Hereditary Hypophosphatemic Rickets

Hereditary hypophosphatemic rickets (HHR) is a rare disorder of renal phosphate wasting and the most common form of heritable rickets. Here, we report a case of an active 25-year-old male with HHR showing atraumatic bilateral femoral neck pseudarthrosis after 4 years of consecutive knee pain. A conservative therapy was administered, taking into account both the risks of surgical treatment and the little impairment even in the sport activities which the patient experienced

Early posttraumatic stress symptoms and levels of distress in trauma patients treated in the resuscitation room: an exploratory study.

Reiner I, Beutel ME, Winter P, Rommens PM, Kuhn S. Early posttraumatic stress symptoms and levels of distress in trauma patients treated in the resuscitation room: an exploratory study. Scandinavian journal of trauma, resuscitation and emergency medicine. 2021;29(1): 22.BACKGROUND: The aim of the present study was to investigate the incidence of psychological distress and posttraumatic stress symptoms in trauma patients who have been recruited from the resuscitation room. Further, we wanted to explore risk factors for posttraumatic stress symptoms, taking different accident types into account.; METHODS: Our sample consisted of 45 patients who have been treated in the resuscitation room and were interviewed within the first ten days after treatment. Type of accident, third party fault, previous mental health problems and pretraumatic stress were examined. Patients were interviewed with respect to their currently felt distress regarding the accident. Posttraumatic stress symptoms were measured with the German version of the Impact of Event Scale. Injury severity was assessed by means of the Injury Severity Score.; RESULTS: Our exploratory and cross-sectional project reveals that more severe injuries were associated with higher distress. However, posttraumatic stress symptoms were predicted by high distress and being involved in a car accident, but not by injury severity.; CONCLUSIONS: We identified two potential risk factors for the development of posttraumatic stress in trauma patients recruited from the resuscitation room: Being involved in a car accident and high distress.; TRIAL REGISTRATION: The project has been registered at the Study Center of Mental Disorders (SPE) at the University Medical Center Mainz (No: 92072014 )

Evaluation of Bone Sialoprotein Coating of Three-Dimensional Printed Calcium Phosphate Scaffolds in a Calvarial Defect Model in Mice

The bioactive coating of calcium phosphate cement (CPC) is a promising approach to enhance the bone-healing properties of bone substitutes. The purpose of this study was to evaluate whether coating CPCs with bone sialoprotein (BSP) results in increased bone formation. Forty-five female C57BL/6NRj mice with an average age of six weeks were divided into three groups. Either a BSP-coated or an uncoated three-dimensional plotted scaffold was implanted into a drilled 2.7-mm diameter calvarial defect, or the defect was left empty (control group; no CPC). Histological analyses revealed that BSP-coated scaffolds were better integrated into the local bone stock eight weeks after implantation. Bone volume/total volume (BV/TV) ratios and bone thickness at the bone⁻implant contact were analyzed via micro computed tomography (µCT) after eight weeks. BSP-coated scaffolds and uncoated CPC scaffolds increased bone thickness in comparison to the control (CPC + BSP: 691.1 ± 253.5 µm, CPC: 603.1 ± 164.4 µm, no CPC: 261.7 ± 37.8 µm, p < 0.01). Accordingly, BV/TV was enhanced in both scaffold groups (CPC + BSP: 1.3 ± 0.5%, CPC: 0.9 ± 0.5%, no CPC: 0.2 ± 0.3%, p < 0.01). The BSP coating showed a tendency towards an increased bone thickness (p = 0.18) and BV/TV (p = 0.18) in comparison to uncoated CPC scaffolds. However, a significant increase in bone formation through BSP coating was not found