scholarly journals Establishment and Evaluation of an In Vitro System for Biophysical Stimulation of Human Osteoblasts

Cells ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1995
Author(s):  
Martin Stephan ◽  
Julius Zimmermann ◽  
Annett Klinder ◽  
Franziska Sahm ◽  
Ursula van Rienen ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Bone Remodeling ◽  
Electric Fields ◽  
Metabolic Activity ◽  
In Vitro System ◽  
Human Osteoblasts ◽  
Capacitively Coupled ◽  
Procollagen Type ◽  
Bone Remodeling Markers

While several studies investigated the effects of mechanical or electrical stimulation on osseointegration and bone fracture healing, little is known about the molecular and cellular impact of combined biophysical stimulation on peri-implant osseointegration. Therefore, we established an in vitro system, capable of applying shear stress and electric fields simultaneously. Capacitively coupled electric fields were used for electrical stimulation, while roughened Ti6Al4V bodies conducted harmonically oscillating micromotions on collagen scaffolds seeded with human osteoblasts. Different variations of single and combined stimulation were applied for three days, while samples loaded with Ti6Al4V bodies and untreated samples served as control. Metabolic activity, expression of osteogenic markers and bone remodeling markers were investigated. While combined stimulation showed no substantial benefit compared to sole mechanical stimulation, we observed that 25 µm micromotions applied by roughened Ti6Al4V bodies led to a significant increase in gene expression of osteocalcin and tissue inhibitor of metalloprotease 1. Additionally, we found an increase in metabolic activity and expression of bone remodeling markers with reduced procollagen type 1 synthesis after 100 mVRMS electrical stimulation. We were able to trigger specific cellular behaviors using different biophysical stimuli. In future studies, different variations of electrical stimulation will be combined with interfacial micromotions.

scholarly journals Re-Differentiation Capacity of Human Chondrocytes in Vitro Following Electrical Stimulation with Capacitively Coupled Fields

2019 ◽  
Vol 8 (11) ◽  
pp. 1771 ◽  
Author(s):  
Simone Krueger ◽  
Sophie Achilles ◽  
Julius Zimmermann ◽  
Thomas Tischer ◽  
Rainer Bader ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Electric Fields ◽  
Ex Vivo ◽  
Human Chondrocytes ◽  
Capacitively Coupled ◽  
Differentiation Capacity ◽  
Cartilage Lesions ◽  
Gene And Protein Expression ◽  
Chondrocytic Differentiation

Treatment of cartilage lesions remains a clinical challenge. Therefore, biophysical stimuli like electric fields seem to be a promising tool for chondrocytic differentiation and treatment of cartilage lesions. In this in vitro study, we evaluated the effects of low intensity capacitively coupled electric fields with an alternating voltage of 100 mVRMS (corresponds to 5.2 × 10−5 mV/cm) or 1 VRMS (corresponds to 5.2 × 10−4 mV/cm) with 1 kHz, on human chondrocytes derived from osteoarthritic (OA) and non-degenerative hyaline cartilage. A reduction of metabolic activity after electrical stimulation was more pronounced in non-degenerative cells. In contrast, DNA contents in OA cells were significantly decreased after electrical stimulation. A difference between 100 mVRMS and 1 VRMS was not detected. However, a voltage-dependent influence on gene and protein expression was observed. Both cell types showed increased synthesis rates of collagen (Col) II, glycosaminoglycans (GAG), and Col I protein following stimulation with 100 mVRMS, whereas this increase was clearly higher in OA cells. Our results demonstrated the sensitization of chondrocytes by alternating electric fields, especially at 100 mVRMS, which has an impact on chondrocytic differentiation capacity. However, analysis of further electrical stimulation parameters should be done to induce optimal hyaline characteristics of ex vivo expanded human chondrocytes.

scholarly journals Establishment of a New Device for Electrical Stimulation of Non-Degenerative Cartilage Cells In Vitro

2021 ◽  
Vol 22 (1) ◽  
pp. 394
Author(s):  
Simone Krueger ◽  
Alexander Riess ◽  
Anika Jonitz-Heincke ◽  
Alina Weizel ◽  
Anika Seyfarth ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Electric Fields ◽  
Cartilage Tissue ◽  
Type I ◽  
Dependent Manner ◽  
New Device ◽  
Alternating Electric Fields ◽  
Cartilage Cells ◽  
Stimulation Of

In cell-based therapies for cartilage lesions, the main problem is still the formation of fibrous cartilage, caused by underlying de-differentiation processes ex vivo. Biophysical stimulation is a promising approach to optimize cell-based procedures and to adapt them more closely to physiological conditions. The occurrence of mechano-electrical transduction phenomena within cartilage tissue is physiological and based on streaming and diffusion potentials. The application of exogenous electric fields can be used to mimic endogenous fields and, thus, support the differentiation of chondrocytes in vitro. For this purpose, we have developed a new device for electrical stimulation of chondrocytes, which operates on the basis of capacitive coupling of alternating electric fields. The reusable and sterilizable stimulation device allows the simultaneous use of 12 cavities with independently applicable fields using only one main supply. The first parameter settings for the stimulation of human non-degenerative chondrocytes, seeded on collagen type I elastin-based scaffolds, were derived from numerical electric field simulations. Our first results suggest that applied alternating electric fields induce chondrogenic re-differentiation at the gene and especially at the protein level of human de-differentiated chondrocytes in a frequency-dependent manner. In future studies, further parameter optimizations will be performed to improve the differentiation capacity of human cartilage cells.

scholarly journals Alternating Electric Fields Modify the Function of Human Osteoblasts Growing on and in the Surroundings of Titanium Electrodes

2020 ◽  
Vol 21 (18) ◽  
pp. 6944
Author(s):  
Franziska Sahm ◽  
Josefin Ziebart ◽  
Anika Jonitz-Heincke ◽  
Doris Hansmann ◽  
Thomas Dauben ◽  
...  
Keyword(s):  
Gene Expression ◽  
Electrical Stimulation ◽  
Electric Fields ◽  
Collagen Type ◽  
Collagen Type I ◽  
Protein Accumulation ◽  
Type I ◽  
Human Osteoblasts ◽  
Alternating Electric Fields ◽  
The Impact

Endogenous electric fields created in bone tissue as a response to mechanical loading are known to influence the activity and differentiation of bone and precursor cells. Thus, electrical stimulation offers an adjunct therapy option for the promotion of bone regeneration. Understanding the influence of electric fields on bone cell function and the identification of suitable electrical stimulation parameters are crucial for the clinical success of stimulation therapy. Therefore, we investigated the impact of alternating electric fields on human osteoblasts that were seeded on titanium electrodes, which delivered the electrical stimulation. Moreover, osteoblasts were seeded on collagen-coated coverslips near the electrodes, representing the bone stock surrounding the implant. Next, 0.2 V, 1.4 V, or 2.8 V were applied to the in vitro system with 20 Hz frequency. After one, three, and seven days, the osteoblast morphology and expression of osteogenic genes were analysed. The actin organisation, as well as the proliferation, were not affected by the electrical stimulation. Changes in the gene expression and protein accumulation after electrical stimulation were voltage-dependent. After three days, the osteogenic gene expression and alkaline phosphatase activity were up to 2.35-fold higher following the electrical stimulation with 0.2 V and 1.4 V on electrodes and coverslips compared to controls. Furthermore, collagen type I mRNA, as well as the amount of the C-terminal propeptide of collagen type I were increased after the stimulation with 0.2 V and 1.4 V, while the higher electrical stimulation with 2.8 V led to decreased levels, especially on the electrodes.

Effect of electrical stimulation on biological cells by capacitive coupling – an efficient numerical study considering model uncertainties

2020 ◽  
Author(s):  
Julius Zimmermann ◽  
RIchard Altenkirch ◽  
Ursula van Rienen
Keyword(s):  
Electrical Stimulation ◽  
Cell Membrane ◽  
Electric Fields ◽  
Biological Samples ◽  
Numerical Study ◽  
Cell Activity ◽  
Cellular Level ◽  
Capacitive Coupling ◽  
Fe Method

Electrical stimulation of biological samples such as tissues and cell cultures attracts growing attention due to its capability of enhancing cell activity, proliferation and differentiation. <br>Eventually, profound knowledge of the underlying mechanisms paves the way for innovative therapeutic devices. <br>Capacitive coupling is one option of delivering electric fields to biological samples and has advantages with regard to biocompatibility.<br>However, the mechanism of interaction is not well understood.<br>Experimental findings could be related to voltage-gated channels, which are triggered by changes of the transmembrane potential (TMP).<br>Numerical simulations by the Finite Element method (FEM) provide a possibility to estimate the TMP.<br>For realistic simulations of <i>in vitro</i> electric stimulation experiments, a bridge from the mesoscopic level down to the cellular level has to be found.<br>A special challenge poses the ratio between the cell membrane (a few <i>nm</i>) and the general setup (some <i>cm</i>).<br>Hence, a full discretization of the cell membrane becomes prohibitively expensive for 3D simulations.<br>We suggest using an approximate FE method that makes 3D multi-scale simulations possible.<br>Starting from an established 2D model, the chosen method is characterized and applied to realistic <i>in vitro</i> situations.<br>A to date not investigated parameter dependency is included and tackled by means of Uncertainty Quantification (UQ) techniques.<br>It reveals a strong, frequency-dependent influence of uncertain parameters on the modeling result.<br><br>

scholarly journals Activation of Human Osteoblasts via Different Bovine Bone Substitute Materials With and Without Injectable Platelet Rich Fibrin in vitro

2021 ◽  
Vol 9 ◽  
Author(s):  
Solomiya Kyyak ◽  
Sebastian Blatt ◽  
Eik Schiegnitz ◽  
Diana Heimes ◽  
Henning Staedt ◽  
...  
Keyword(s):  
Metabolic Activity ◽  
Bone Substitute ◽  
Bone Morphogenetic Protein 2 ◽  
Bovine Bone ◽  
Human Osteoblasts ◽  
Time Points ◽  
Significant Difference ◽  
Bone Substitute Materials ◽  
Substitute Materials

IntroductionThe aim of the in vitro study was to compare the effect of four bovine bone substitute materials (XBSM) with and without injectable platelet-reach fibrin for viability and metabolic activity of human osteoblasts (HOB) as well as expression of alkaline phosphatase (ALP), bone morphogenetic protein 2 (BMP-2), and osteonectin (OCN).Materials and MethodsCerabone® (CB), Bio-Oss® (BO), Creos Xenogain® (CX) and MinerOss® X (MO) ± i-PRF were incubated with HOB. At day 3, 7, and 10, cell viability and metabolic activity as well as expression of ALP, OCN, and BMP-2, was examined.ResultsFor non-i-PRF groups, the highest values concerning viability were seen for CB at all time points. Pre-treatment with i-PRF increased viability in all groups with the highest values for CB-i-PRF after 3 and 7 and for CX-i-PRF after 10 days. For metabolic activity, the highest rate among non-i-PRF groups was seen for MO at day 3 and for CB at day 7 and 10. Here, i-PRF groups showed higher values than non-i-PRF groups (highest values: CB + i-PRF) at all time points. There was no difference in ALP-expression between groups. For OCN expression in non-i-PRF groups, CB showed the highest values after day 3, CX after day 7 and 10. Among i-PRF-groups, the highest values were seen for CX + i-PRF. At day 3, the highest BMP-2 expression was observed for CX. Here, for i-PRF groups, the highest increase was seen for CX + i-PRF at day 3. At day 7 and 10, there was no significant difference among groups.ConclusionXBSM sintered under high temperature showed increased HOB viability and metabolic activity through the whole period when compared to XBSM manufactured at lower temperatures. Overall, the combination of XBSM with i-PRF improved all cellular parameters, ALP and BMP-2 expression at earlier stages as well as OCN expression at later stages.

Effect of electrical stimulation on biological cells by capacitive coupling – an efficient numerical study considering model uncertainties

2020 ◽  
Author(s):  
Julius Zimmermann ◽  
RIchard Altenkirch ◽  
Ursula van Rienen
Keyword(s):  
Electrical Stimulation ◽  
Cell Membrane ◽  
Electric Fields ◽  
Biological Samples ◽  
Numerical Study ◽  
Cell Activity ◽  
Cellular Level ◽  
Capacitive Coupling ◽  
Fe Method

Electrical stimulation of biological samples such as tissues and cell cultures attracts growing attention due to its capability of enhancing cell activity, proliferation and differentiation. <br>Eventually, profound knowledge of the underlying mechanisms paves the way for innovative therapeutic devices. <br>Capacitive coupling is one option of delivering electric fields to biological samples and has advantages with regard to biocompatibility.<br>However, the mechanism of interaction is not well understood.<br>Experimental findings could be related to voltage-gated channels, which are triggered by changes of the transmembrane potential (TMP).<br>Numerical simulations by the Finite Element method (FEM) provide a possibility to estimate the TMP.<br>For realistic simulations of <i>in vitro</i> electric stimulation experiments, a bridge from the mesoscopic level down to the cellular level has to be found.<br>A special challenge poses the ratio between the cell membrane (a few <i>nm</i>) and the general setup (some <i>cm</i>).<br>Hence, a full discretization of the cell membrane becomes prohibitively expensive for 3D simulations.<br>We suggest using an approximate FE method that makes 3D multi-scale simulations possible.<br>Starting from an established 2D model, the chosen method is characterized and applied to realistic <i>in vitro</i> situations.<br>A to date not investigated parameter dependency is included and tackled by means of Uncertainty Quantification (UQ) techniques.<br>It reveals a strong, frequency-dependent influence of uncertain parameters on the modeling result.<br><br>

scholarly journals Promoting osseointegration with electrical stimulation: a review

2021 ◽  
Author(s):  
Emily Pettersen ◽  
Jenna Anderson ◽  
Max Ortiz-Catalan
Keyword(s):  
Electrical Stimulation ◽  
Electric Fields ◽  
Meta Analysis ◽  
Implant Surface ◽  
Power Sources ◽  
Stimulation Parameters ◽  
Bone Quantity ◽  
Major Factors

<p>Electrical stimulation has shown to be a promising approach for promoting osseointegration in bone-anchored implants, where osseointegration defines the biological bonding between an implant surface and bone tissue. Bone-anchored implants are used in the rehabilitation of hearing and limb loss, and extensively in edentulous patients. Inadequate osseointegration is one of the major factors of implant failure that could be prevented by accelerating or enhancing the osseointegration process by artificial means. In this article, we reviewed the efforts to enhance the biofunctionality at the implant-bone interface with electrical stimulation using various approaches such as different electrode configurations, power sources, and waveform-dependent stimulation parameters tested in different <i>in vitro</i> and <i>in vivo</i> models. We reviewed and compared studies from the last 45 years and found nonuniform protocols with disparities in cell type and animal model, implant location, experimental timeline, implant material, evaluation assays, and type of electrical stimulation. The reporting of stimulation parameters was also found to be inconsistent and incomplete throughout the literature. Studies using <i>in vitro</i> models showed that osteoblasts were sensitive to the magnitude of the electric field and duration of exposure, and such variables similarly affected bone quantity around implants in <i>in vivo </i>investigations. Most studies showed benefits of electrical stimulation in the underlying processes leading to osseointegration, and therefore we found the idea of promoting osseointegration by using electric fields to be supported by the available evidence. However, such an effect has not been demonstrated conclusively nor optimally in humans. We found that optimal stimulation parameters have not been thoroughly investigated and this remains an important step towards the clinical translation of this concept. In addition, there is a need for reporting standards to enable meta-analysis for evidence-based treatments.</p>

Promoting osseointegration with electrical stimulation: a review

2021 ◽  
Author(s):  
Emily Pettersen ◽  
Jenna Anderson ◽  
Max Ortiz-Catalan
Keyword(s):  
Electrical Stimulation ◽  
Electric Fields ◽  
Meta Analysis ◽  
Implant Surface ◽  
Power Sources ◽  
Stimulation Parameters ◽  
Bone Quantity ◽  
Major Factors

<p>Electrical stimulation has shown to be a promising approach for promoting osseointegration in bone-anchored implants, where osseointegration defines the biological bonding between an implant surface and bone tissue. Bone-anchored implants are used in the rehabilitation of hearing and limb loss, and extensively in edentulous patients. Inadequate osseointegration is one of the major factors of implant failure that could be prevented by accelerating or enhancing the osseointegration process by artificial means. In this article, we reviewed the efforts to enhance the biofunctionality at the implant-bone interface with electrical stimulation using various approaches such as different electrode configurations, power sources, and waveform-dependent stimulation parameters tested in different <i>in vitro</i> and <i>in vivo</i> models. We reviewed and compared studies from the last 45 years and found nonuniform protocols with disparities in cell type and animal model, implant location, experimental timeline, implant material, evaluation assays, and type of electrical stimulation. The reporting of stimulation parameters was also found to be inconsistent and incomplete throughout the literature. Studies using <i>in vitro</i> models showed that osteoblasts were sensitive to the magnitude of the electric field and duration of exposure, and such variables similarly affected bone quantity around implants in <i>in vivo </i>investigations. Most studies showed benefits of electrical stimulation in the underlying processes leading to osseointegration, and therefore we found the idea of promoting osseointegration by using electric fields to be supported by the available evidence. However, such an effect has not been demonstrated conclusively nor optimally in humans. We found that optimal stimulation parameters have not been thoroughly investigated and this remains an important step towards the clinical translation of this concept. In addition, there is a need for reporting standards to enable meta-analysis for evidence-based treatments.</p>

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