In vitro electromagnetically stimulated SAOS-2 osteoblasts inside porous hydroxyapatite

The Use of Pulsed Electromagnetic Fields to Promote Bone Responses to Biomaterials In Vitro and In Vivo

Implantable biomaterials are extensively used to promote bone regeneration or support endosseous prosthesis in orthopedics and dentistry. Their use, however, would benefit from additional strategies to improve bone responses. Pulsed Electromagnetic Fields (PEMFs) have long been known to act on osteoblasts and bone, affecting their metabolism, in spite of our poor understanding of the underlying mechanisms. Hence, we have the hypothesis that PEMFs may also ameliorate cell responses to biomaterials, improving their growth, differentiation, and the expression of a mature phenotype and therefore increasing the tissue integration of the implanted devices and their clinical success. A broad range of settings used for PEMFs stimulation still represents a hurdle to better define treatment protocols and extensive research is needed to overcome this issue. The present review includes studies that investigated the effects of PEMFs on the response of bone cells to different classes of biomaterials and the reports that focused on in vivo investigations of biomaterials implanted in bone.

Model of Murine Ventricular Cardiac Tissue for In Vitro Kinematic-Dynamic Studies of Electromagnetic and β-Adrenergic Stimulation

In a model of murine ventricular cardiac tissue in vitro, we have studied the inotropic effects of electromagnetic stimulation (frequency, 75 Hz), isoproterenol administration (10 μM), and their combination. In particular, we have performed an image processing analysis to evaluate the kinematics and the dynamics of beating cardiac syncytia starting from the video registration of their contraction movement. We have found that the electromagnetic stimulation is able to counteract the β-adrenergic effect of isoproterenol and to elicit an antihypertrophic response.

Histological and micro-computed tomographic observations after maxillary sinus augmentation with porous hydroxyapatite alloplasts: a clinical case series

Background

It is important to visualize the phenomenon which occurs in actual clinical cases to decide the timing of implant placement subsequently after sinus graft. Although several clinical cases of bone augmentation using xenograft have been evaluated, the number of those reports which have described bone remodeling by alloplasty are not sufficient.

Findings

In the present report, to investigate bone remodeling histologically after maxillary sinus augmentation with porous hydroxyapatite alloplast, bone cores from the sinus floor of three female nonsmoking patients (aged 64–73 years) were collected 6 months after sinus lift surgery, embedded in methyl methacrylate resin, and prepared by conventional methods. Bone architecture and graft residues were evaluated by micro-computed tomography of the same specimens. Hematoxylin–eosin and Villanueva–Goldner staining revealed mature osteoblasts and multinucleated osteoclasts on the grafted sinus floor and surface of residual hydroxyapatite particles. The particulate interspace was partially filled with osteoid and calcified tissue and showed active vascularization.

Conclusion

The results suggested that bone regeneration and angiogenesis within and between porous hydroxyapatite particles were sufficiently found after 6 month histologically in the grafted sinus floor.

Electronic supplementary material

The online version of this article (doi:10.1186/s40064-016-1885-2) contains supplementary material, which is available to authorized users.

Biomineralization and biocompatibility studies of bone conductive scaffolds containing poly(3,4-ethylenedioxythiophene):poly(4-styrene sulfonate) (PEDOT:PSS)

Considering the well-known phenomenon of enhancing bone healing by applying electromagnetic stimulation, manufacturing conductive bone scaffolds is on demand to facilitate the delivery of electromagnetic stimulation to the injured region, which in turn significantly expedites the healing procedure in tissue engineering methods. For this purpose, hybrid conductive scaffolds composed of poly(3,4-ethylenedioxythiophene), poly(4-styrene sulfonate) (

PEDOT

PSS), gelatin (Gel), and bioactive glass (BaG) were produced employing freeze drying technique. Concentration of

PEDOT

PSS were optimized to design the most appropriate conductive scaffold in terms of biocompatibility and cell proliferation. More specifically, scaffolds with four different compositions of 0, 0.1, 0.3 and 0.6% (w/w)

PEDOT

PSS in the mixture of 10% (w/v) Gel and 30% (w/v) BaG were synthesized. Immersing the scaffolds in simulated body fluid (SBF), we evaluated the bioactivity of samples, and the biomineralization were studied in details using scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction analysis and Fourier transform infrared spectroscopy. By performing cytocompatibility analyses for 21 days using adult human mesenchymal stem cells, we concluded that the scaffolds with 0.3% (w/w)

PEDOT

PSS and conductivity of 170 μS/m has the optimized composition and further increasing the

PEDOT

PSS content has inverse effect on cell proliferation. Based on our finding, addition of this optimized amount of

PEDOT

PSS to our composition can increase the cell viability more than 4 times compared to a nonconductive composition.

Electro-magnetic field promotes osteogenic differentiation of BM-hMSCs through a selective action on Ca(2+)-related mechanisms

Exposure to Pulsed Electromagnetic Field (PEMF) has been shown to affect proliferation and differentiation of human mesenchymal stem cells derived from bone marrow stroma (BM-hMSC). These cells offer considerable promise in the field of regenerative medicine, but their clinical application is hampered by major limitations such as poor availability and the time required to differentiate up to a stage suitable for implantation. For this reason, several research efforts are focusing on identifying strategies to speed up the differentiation process. In this work we investigated the in vitro effect of PEMF on Ca²⁺-related mechanisms promoting the osteogenic differentiation of BM-hMSC. Cells were daily exposed to PEMF while subjected to osteogenic differentiation and various Ca²⁺-related mechanisms were monitored using multiple approaches for identifying functional and structural modifications related to this process. The results indicate that PEMF exposure promotes chemically induced osteogenesis by mechanisms that mainly interfere with some of the calcium-related osteogenic pathways, such as permeation and regulation of cytosolic concentration, leaving others, such as extracellular deposition, unaffected. The PEMF effect is primarily associated to early enhancement of intracellular calcium concentration, which is proposed here as a reliable hallmark of the osteogenic developmental stage.