scholarly journals Programable Active Fixator System for Systematic In Vivo Investigation of Bone Healing Processes

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 17
Author(s):  
Jan Barcik ◽  
Manuela Ernst ◽  
Constantin E. Dlaska ◽  
Ludmil Drenchev ◽  
Stephan Zeiter ◽  
...  
Keyword(s):  
Bone Healing ◽  
Weight Bearing ◽  
Control Unit ◽  
Force Sensor ◽  
Systematic Investigation ◽  
Autonomous Operation ◽  
Double Osteotomy ◽  
Implanted Devices ◽  
Healing Processes

This manuscript introduces a programable active bone fixator system that enables systematic investigation of bone healing processes in a sheep animal model. In contrast to previous systems, this solution combines the ability to precisely control the mechanical conditions acting within a fracture with continuous monitoring of the healing progression and autonomous operation of the system throughout the experiment. The active fixator system was implemented on a double osteotomy model that shields the experimental fracture from the influence of the animal’s functional loading. A force sensor was integrated into the fixator to continuously measure stiffness of the repair tissue as an indicator for healing progression. A dedicated control unit was developed that allows programing of different loading protocols which are later executed autonomously by the active fixator. To verify the feasibility of the system, it was implanted in two sheep with different loading protocols, mimicking immediate and delayed weight-bearing, respectively. The implanted devices operated according to the programmed protocols and delivered seamless data over the whole course of the experiment. The in vivo trial confirmed the feasibility of the system. Hence, it can be applied in further preclinical studies to better understand the influence of mechanical conditions on fracture healing.

scholarly journals Facilitation of Bone Healing Processes Based on the Developmental Function of Meox2 in Tooth Loss Lesion

2020 ◽  
Vol 21 (22) ◽  
pp. 8701
Author(s):  
Tae-Young Kim ◽  
Jae-Kyung Park ◽  
Yam Prasad Aryal ◽  
Eui-Seon Lee ◽  
Sanjiv Neupane ◽  
...  
Keyword(s):  
Bone Healing ◽  
Tooth Loss ◽  
Pathological Condition ◽  
Developmental Regulation ◽  
Homeobox Gene ◽  
Osteogenic Potential ◽  
Micro Computed Tomography ◽  
Periodontal Ligament Fibroblasts ◽  
Healing Processes

In the present study, we examined the bone healing capacity of Meox2, a homeobox gene that plays essential roles in the differentiation of a range of developing tissues, and identified its putative function in palatogenesis. We applied the knocking down of Meox2 in human periodontal ligament fibroblasts to examine the osteogenic potential of Meox2. Additionally, we applied in vivo periodontitis induced experiment to reveal the possible application of Meox2 knockdown for 1 and 2 weeks in bone healing processes. We examined the detailed histomorphological changes using Masson’s trichrome staining and micro-computed tomography evaluation. Moreover, we observed the localization patterns of various signaling molecules, including α-SMA, CK14, IL-1β, and MPO to examine the altered bone healing processes. Furthermore, we investigated the process of bone formation using immunohistochemistry of Osteocalcin and Runx2. On the basis of the results, we suggest that the knocking down of Meox2 via the activation of osteoblast and modulation of inflammation would be a plausible answer for bone regeneration as a gene therapy. Additionally, we propose that the purpose-dependent selection and application of developmental regulation genes are important for the functional regeneration of specific tissues and organs, where the pathological condition of tooth loss lesion would be.

scholarly journals Ibudilast Mitigates Delayed Bone Healing Caused by Lipopolysaccharide by Altering Osteoblast and Osteoclast Activity

2021 ◽  
Vol 22 (3) ◽  
pp. 1169
Author(s):  
Yuhan Chang ◽  
Chih-Chien Hu ◽  
Ying-Yu Wu ◽  
Steve W. N. Ueng ◽  
Chih-Hsiang Chang ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bone Formation ◽  
Cancellous Bone ◽  
Bone Healing ◽  
Bone Bridge ◽  
Cell Wall Components ◽  
Osteoclast Activity ◽  
Wall Components

Bacterial infection in orthopedic surgery is challenging because cell wall components released after bactericidal treatment can alter osteoblast and osteoclast activity and impair fracture stability. However, the precise effects and mechanisms whereby cell wall components impair bone healing are unclear. In this study, we characterized the effects of lipopolysaccharide (LPS) on bone healing and osteoclast and osteoblast activity in vitro and in vivo and evaluated the effects of ibudilast, an antagonist of toll-like receptor 4 (TLR4), on LPS-induced changes. In particular, micro-computed tomography was used to reconstruct femoral morphology and analyze callus bone content in a femoral defect mouse model. In the sham-treated group, significant bone bridge and cancellous bone formation were observed after surgery, however, LPS treatment delayed bone bridge and cancellous bone formation. LPS inhibited osteogenic factor-induced MC3T3-E1 cell differentiation, alkaline phosphatase (ALP) levels, calcium deposition, and osteopontin secretion and increased the activity of osteoclast-associated molecules, including cathepsin K and tartrate-resistant acid phosphatase in vitro. Finally, ibudilast blocked the LPS-induced inhibition of osteoblast activation and activation of osteoclast in vitro and attenuated LPS-induced delayed callus bone formation in vivo. Our results provide a basis for the development of a novel strategy for the treatment of bone infection.

scholarly journals OP0244 A PRECLINICAL TESTING TOOL: THE IN VITRO 3D FRACTURE GAP MODEL

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 154.1-154
Author(s):  
M. Pfeiffenberger ◽  
A. Damerau ◽  
P. Hoff ◽  
A. Lang ◽  
F. Buttgereit ◽  
...  
Keyword(s):  
Fracture Healing ◽  
Bone Healing ◽  
Inflammatory Markers ◽  
Initial Phase ◽  
Gap Model ◽  
Osteogenic Markers ◽  
Immunosuppressed Patients ◽  
The Impact

Background:Approximately 10% of fractures lead to significant fracture healing disorders, with a tendency to further increase due to the aging population. Of note, especially immunosuppressed patients with ongoing inflammation show difficulties in the correct course of fracture healing leading to fracture healing disorders. Most notably, invading immune cells and secreted cytokines are considered to provide an inflammatory microenvironment within the fracture gap, primarily during the initial phase of fracture healing. Current research has the focus on small animal models, facing the problem of translation towards the human system. In order to improve the therapy of fracture healing disorders, we have developed a human cell-basedin vitromodel to mimic the initial phase of fracture healing adequately. This model will be used for the development of new therapeutic strategies.Objectives:Our aim is to develop anin vitro3D fracture gap model (FG model) which mimics thein vivosituation in order to provide a reliable preclinical test system for fracture healing disorders.Methods:To assemble our FG model, we co-cultivated coagulated peripheral blood and primary human mesenchymal stromal cells (MSCs) mimicking the fracture hematoma (FH model) together with a scaffold-free bone-like construct mimicking the bony part of the fracture gap for 48 h under hypoxic conditions (n=3), in order to reflect thein vivosituation after fracture most adequately. To analyze the impact of the bone-like construct on thein vitroFH model with regard to its osteogenic induction capacity, we cultivated the fracture gap models in either medium with or without osteogenic supplements. To analyze the impact of Deferoxamine (DFO, known to foster fracture healing) on the FG model, we further treated our FG models with either 250 µmol DFO or left them untreated. After incubation and subsequent preparation of the fracture hematomas, we evaluated gene expression of osteogenic (RUNX2,SPP1), angiogenic (VEGF,IL8), inflammatory markers (IL6,IL8) and markers for the adaptation towards hypoxia (LDHA,PGK1) as well as secretion of cytokines/chemokines using quantitative PCR and multiplex suspension assay, respectively.Results:We found via histology that both the fracture hematoma model and the bone-like construct had close contact during the incubation, allowing the cells to interact with each other through direct cell-cell contact, signal molecules or metabolites. Additionally, we could show that the bone-like constructs induced the upregulation of osteogenic markers (RUNX2, SPP1) within the FH models irrespective of the supplementation of osteogenic supplements. Furthermore, we observed an upregulation of hypoxia-related, angiogenic and osteogenic markers (RUNX2,SPP1) under the influence of DFO, and the downregulation of inflammatory markers (IL6,IL8) as compared to the untreated control. The latter was also confirmed on protein level (e.g. IL-6 and IL-8). Within the bone-like constructs, we observed an upregulation of angiogenic markers (RNA-expression ofVEGF,IL8), even more pronounced under the treatment of DFO.Conclusion:In summary, our findings demonstrate that our establishedin vitroFG model provides all osteogenic cues to induce the initial bone healing process, which could be enhanced by the fracture-healing promoting substance DFO. Therefore, we conclude that our model is indeed able to mimic correctly the human fracture gap situation and is therefore suitable to study the influence and efficacy of potential therapeutics for the treatment of bone healing disorders in immunosuppressed patients with ongoing inflammation.Disclosure of Interests:Moritz Pfeiffenberger: None declared, Alexandra Damerau: None declared, Paula Hoff: None declared, Annemarie Lang: None declared, Frank Buttgereit Grant/research support from: Amgen, BMS, Celgene, Generic Assays, GSK, Hexal, Horizon, Lilly, medac, Mundipharma, Novartis, Pfizer, Roche, and Sanofi., Timo Gaber: None declared

scholarly journals Can Optimizing the Mechanical Environment Deliver a Clinically Significant Reduction in Fracture Healing Time?

Biomedicines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 691
Author(s):  
Jan Barcik ◽  
Devakara R. Epari
Keyword(s):  
Fracture Healing ◽  
Bone Healing ◽  
Mechanical Stimulation ◽  
Callus Formation ◽  
Weight Bearing ◽  
Healing Process ◽  
Healing Time ◽  
Mechanical Environment ◽  
Clinically Significant ◽  
The Impact

The impact of the local mechanical environment in the fracture gap on the bone healing process has been extensively investigated. Whilst it is widely accepted that mechanical stimulation is integral to callus formation and secondary bone healing, treatment strategies that aim to harness that potential are rare. In fact, the current clinical practice with an initially partial or non-weight-bearing approach appears to contradict the findings from animal experiments that early mechanical stimulation is critical. Therefore, we posed the question as to whether optimizing the mechanical environment over the course of healing can deliver a clinically significant reduction in fracture healing time. In reviewing the evidence from pre-clinical studies that investigate the influence of mechanics on bone healing, we formulate a hypothesis for the stimulation protocol which has the potential to shorten healing time. The protocol involves confining stimulation predominantly to the proliferative phase of healing and including adequate rest periods between applications of stimulation.

scholarly journals Ovarian Accumulation of Nanoemulsions: Impact of Mice Age and Particle Size

2021 ◽  
Vol 22 (15) ◽  
pp. 8283
Author(s):  
Eike Folker Busmann ◽  
Julia Kollan ◽  
Karsten Mäder ◽  
Henrike Lucas
Keyword(s):  
Particle Size ◽  
Ex Vivo ◽  
Reticuloendothelial System ◽  
Systematic Investigation ◽  
Measured Signal ◽  
Reproductive Aging ◽  
Sex Steroid Hormone ◽  
Adult Mice ◽  
Radiant Efficiency

Nanotechnology in the field of drug delivery comes with great benefits due to the unique physicochemical properties of newly developed nanocarriers. However, they may come as well with severe toxicological side effects because of unwanted accumulation in organs outside of their targeted site of actions. Several studies showed an unintended accumulation of various nanocarriers in female sex organs, especially in the ovaries. Some led to inflammation, fibrosis, or decreasing follicle numbers. However, none of these studies investigated ovarian accumulation in context to both reproductive aging and particle size. Besides the influences of particle size, the biodistribution profile may be altered as well by reproductive aging because of reduced capacities of the reticuloendothelial system (RES), changes in sex steroid hormone levels as well as altering ovarian stromal blood flow. This systematic investigation of the biodistribution of intravenously (i.v) injected nanoemulsions revealed significant dependencies on the two parameters particle size and age starting from juvenile prepubescent to senescent mice. Using fluorescent in vivo and ex vivo imaging, prepubescent mice showed nearly no accumulation of nanoemulsion in their uteri and ovaries, but high accumulations in the organs of the RES liver and spleen independently of the particle size. In fertile adult mice, the accumulation increased significantly in the ovaries with an increased particle size of the nanoemulsions by nearly doubling the portion of the average radiant efficiency (PARE) to ~10% of the total measured signal of all excised organs. With reproductive aging and hence loss of fertility in senescent mice, the accumulation decreased again to moderate levels, again independently of the particle size. In conclusion, the ovarian accumulation of these nanocarriers depended on both the age plus the particle size during maturity.

scholarly journals Zn-Containing Membranes for Guided Bone Regeneration in Dentistry

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1797
Author(s):  
Manuel Toledano ◽  
Marta Vallecillo-Rivas ◽  
María T. Osorio ◽  
Esther Muñoz-Soto ◽  
Manuel Toledano-Osorio ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bone Regeneration ◽  
Bone Healing ◽  
Bone Repair ◽  
Complex Modulus ◽  
Bacterial Colonization ◽  
Guided Bone Regeneration ◽  
M2 Macrophage

Barrier membranes are employed in guided bone regeneration (GBR) to facilitate bone in-growth. A bioactive and biomimetic Zn-doped membrane with the ability to participate in bone healing and regeneration is necessary. The aim of the present study is to state the effect of doping the membranes for GBR with zinc compounds in the improvement of bone regeneration. A literature search was conducted using electronic databases, such as PubMed, MEDLINE, DIMDI, Embase, Scopus and Web of Science. A narrative exploratory review was undertaken, focusing on the antibacterial effects, physicochemical and biological properties of Zn-loaded membranes. Bioactivity, bone formation and cytotoxicity were analyzed. Microstructure and mechanical properties of these membranes were also determined. Zn-doped membranes have inhibited in vivo and in vitro bacterial colonization. Zn-alloy and Zn-doped membranes attained good biocompatibility and were found to be non-toxic to cells. The Zn-doped matrices showed feasible mechanical properties, such as flexibility, strength, complex modulus and tan delta. Zn incorporation in polymeric membranes provided the highest regenerative efficiency for bone healing in experimental animals, potentiating osteogenesis, angiogenesis, biological activity and a balanced remodeling. Zn-loaded membranes doped with SiO2 nanoparticles have performed as bioactive modulators provoking an M2 macrophage increase and are a potential biomaterial for promoting bone repair. Zn-doped membranes have promoted pro-healing phenotypes.

Oxysterols enhance osteoblast differentiation in vitro and bone healing in vivo

2007 ◽  
Vol 25 (11) ◽  
pp. 1488-1497 ◽  
Author(s):  
Tara L. Aghaloo ◽  
Christopher M. Amantea ◽  
Catherine M. Cowan ◽  
Jennifer A. Richardson ◽  
Ben M. Wu ◽  
...  
Keyword(s):  
Bone Healing ◽  
Osteoblast Differentiation

scholarly journals [3H]proline incorporation and hydroxyproline concentration in articular cartilage during the development of osteoarthritis caused by immobilization. A study in vivo with rabbits

1981 ◽  
Vol 200 (2) ◽  
pp. 435-440 ◽  
Author(s):  
T Videman ◽  
I Eronen ◽  
T Candolin
Keyword(s):  
Total Protein ◽  
Collagen Synthesis ◽  
Weight Bearing ◽  
Specific Radioactivity ◽  
Collagen Content ◽  
Synthetic Activity ◽  
Synthesis Rate ◽  
Hydroxyproline Concentration ◽  
Proline Incorporation

Proline metabolism in vivo was studied during the development of immobilization osteoarthritis in rabbits. Collagen content was measured as the hydroxyproline concentration of the tissue in question. The incorporation of [3H]proline was used as the indicator for total protein synthesis; collagen synthesis rate was estimated from measurements of the specific radioactivity of hydroxyproline. Cartilage samples from knee and hip joints were analysed after 3, 7, 11, 18, 35 and 56 days of immobilization. The total protein and collagen synthesis rates of the immobilized legs increased and reached a maximum after 11-35 days. Although they decreased thereafter, these rates remained elevated to the end of the experiment. A slight increase in the synthetic activity of the non-immobilized contralateral legs was also detected after 7--18 days of immobilization. The isotope incorporation was markedly higher in tibial marginal tissue than in weight-bearing cartilage. In spite of the increased synthesis, no clear changes were found in the collagen content of the tissues studied during the experiment.

Mechanical Failure of Angle Locking Plates in Distal Comminuted Tibial Fractures

2016 ◽  
Vol 695 ◽  
pp. 118-122 ◽  
Author(s):  
Razvan Ene ◽  
Zsombor Panti ◽  
Mihai Nica ◽  
Marian Pleniceanu ◽  
Patricia Ene ◽  
...  
Keyword(s):  
Internal Fixation ◽  
Bone Healing ◽  
Tibial Fracture ◽  
Weight Bearing ◽  
Healing Process ◽  
Biomechanical Properties ◽  
Implant Failure ◽  
Locking Plates ◽  
Non Union ◽  
Tibial Pilon

Distal comminuted tibial fracture with or without intra-articular involvement is a very common injury of the lower limb, especially in younger patients due to high energy trauma. The anatomical and biomechanical properties of this segment of tibia, makes this pathology a major surgical challenge with a preserved clinical outcome. The aim of this study is to present different outcome of tibial fracture, treated with open reduction and internal fixation (ORIF) with titanium angle locking plates (ALP) and to underline the physiological and non-physiological bone healing effects on implants. In this study we included 48 patients with tibial pilon fracture who underwent to ORIF, applying ALP in the Orthopedics and Trauma department of the University Emergency Hospital in Bucharest. Due to preserved biomechanical properties of ALP and this anatomical region, weight bearing is not allowed till 6 to 8 weeks. Comminuted fracture of this part of tibia often have de-vascularized bony fragments which leads to delayed union or non-union. These complications often lead to implant failure, improper bone healing or non-union. Internal fixation with angle stable screws, offers a good stability of reduction in the early postoperative period. Titanium angle locking plates offers good anatomical reduction and stable fixation in the early period of healing process. Due to its rigid, fixed position of the screws in the plates, bone remodelling during healing process and early weight bearing, increases the mechanical failure of implant.Keywords: tibial pilon fractures, angle locking plates, implant failure.

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