Considering the Value of 3D Cultures for Enhancing the Understanding of Adhesion, Proliferation, and Osteogenesis on Titanium Dental Implants

Background: Individuals with pathologic conditions and restorative deficiencies might benefit from a combinatorial approach encompassing stem cells and dental implants; however, due to the various surface textures and coatings, the influence of titanium dental implants on cells exhibits extensive, wide variations. Three-dimensional (3D) cultures of stem cells on whole dental implants are superior in testing implant properties and were used to examine their capabilities thoroughly. Materials and methods: The surface micro-topography of five titanium dental implants manufactured by sandblasting with titanium, aluminum, corundum, or laser sintered and laser machined was compared in this study. After characterization, including particle size distribution and roughness, the adhesion, proliferation, and viability of adipose-derived stem cells (ADSCs) cultured on the whole-body implants were tested at three time points (one to seven days). Finally, the capacity of the implant to induce ADSCs' spontaneous osteoblastic differentiation was examined at the same time points, assessing the gene expression of collagen type 1 (coll-I), osteonectin (osn), alkaline phosphatase (alp), and osteocalcin (osc). Results: Laser-treated (Laser Mach and Laser Sint) implants exhibited the highest adhesion degree; however, limited proliferation was observed, except for Laser Sint implants, while viability differences were seen throughout the three time points, except for Ti Blast implants. Sandblasted surfaces (Al Blast, Cor Blast, and Ti Blast) outpaced the laser-treated ones, inducing higher amounts of coll-I, osn, and alp, but not osc. Among the sandblasted surfaces, Ti Blast showed moderate roughness and the highest superficial texture density, favoring the most significant spontaneous differentiation relative to all the other implant surfaces. Conclusions: The results indicate that 3D cultures of stem cells on whole-body titanium dental implants is a practical and physiologically appropriate way to test the biological characteristics of the implants, revealing peculiar differences in ADSCs' adhesion, proliferation, and activity toward osteogenic commitment in the absence of specific osteoinductive cues. In addition, the 3D method would allow researchers to test various implant surfaces more thoroughly. Integrating with preconditioned stem cells would inspire a more substantial combinatorial approach to promote a quicker recovery for patients with restorative impairments

Assessing the Efficacy of Whole-Body Titanium Dental Implant Surface Modifications in Inducing Adhesion, Proliferation, and Osteogenesis in Human Adipose Tissue Stem Cells

Abstract: Background: Although the influence of titanium implants’ micro-surface properties on tita- nium discs has been extensively investigated, the research has not taken into consideration their whole-body effect, which may be considered possible using a combinatorial approach. Methods: Five titanium dental implants with a similar moderate roughness and different surface textures were thor- oughly characterized. The cell adhesion and proliferation were assessed after adipose-tissue-derived stem cells (ADSCs) were seeded on whole-body implants. The implants’ inductive properties were assessed by evaluating the osteoblastic gene expression. Results: The surface micro-topography was analyzed, showing that hydroxyapatite (HA)-blasted and bland acid etching implants had the highest roughness and a lower number of surface particles. Cell adhesion was observed after 24 h on all the implants, with the highest score registered for the HA-blasted and bland acid etching implants. Cell proliferation was observed only on the laser-treated and double-acid-etched surfaces. The ADSCs ex- pressed collagen type I, osteonectin, and alkaline phosphatase on all the implant surfaces, with high levels on the HA-treated surfaces, which also triggered osteocalcin expression on day seven. Conclu- sions: The findings of this study show that the morphology and treatment of whole titanium dental implants, primarily HA-treated and bland acid etching implants, impact the adherence and activity of ADSCs in osteogenic differentiation in the absence of specific osteo-inductive signals

Considering the Value of 3D Cultures for Enhancing the Understanding of Adhesion, Proliferation, and Osteogenesis on Titanium Dental Implants

Background: Individuals with pathologic conditions and restorative deficiencies might benefit from a combinatorial approach encompassing stem cells and dental implants; however, due to the various surface textures and coatings, the influence of titanium dental implants on cells exhibits extensive, wide variations. Three-dimensional (3D) cultures of stem cells on whole dental implants are superior in testing implant properties and were used to examine their capabilities thoroughly. Materials and methods: The surface micro-topography of five titanium dental implants manufactured by sandblasting with titanium, aluminum, corundum, or laser sintered and laser machined was compared in this study. After characterization, including particle size distribution and roughness, the adhesion, proliferation, and viability of adipose-derived stem cells (ADSCs) cultured on the whole-body implants were tested at three time points (one to seven days). Finally, the capacity of the implant to induce ADSCs’ spontaneous osteoblastic differentiation was examined at the same time points, assessing the gene expression of collagen type 1 (coll-I), osteonectin (osn), alkaline phosphatase (alp), and osteocalcin (osc). Results: Laser-treated (Laser Mach and Laser Sint) implants exhibited the highest adhesion degree; however, limited proliferation was observed, except for Laser Sint implants, while viability differences were seen throughout the three time points, except for Ti Blast implants. Sandblasted surfaces (Al Blast, Cor Blast, and Ti Blast) outpaced the laser-treated ones, inducing higher amounts of coll-I, osn, and alp, but not osc. Among the sandblasted surfaces, Ti Blast showed moderate roughness and the highest superficial texture density, favoring the most significant spontaneous differentiation relative to all the other implant surfaces. Conclusions: The results indicate that 3D cultures of stem cells on whole-body titanium dental implants is a practical and physiologically appropriate way to test the biological characteristics of the implants, revealing peculiar differences in ADSCs’ adhesion, proliferation, and activity toward osteogenic commitment in the absence of specific osteoinductive cues. In addition, the 3D method would allow researchers to test various implant surfaces more thoroughly. Integrating with preconditioned stem cells would inspire a more substantial combinatorial approach to promote a quicker recovery for patients with restorative impairments

A worm gel-based 3D model to elucidate the paracrine interaction between multiple myeloma and mesenchymal stem cells

Multiple myeloma (MM) is a malignancy of terminally-differentiated plasma cells that develops mainly inside the bone marrow (BM) microenvironment. It is well known that autocrine and paracrine signals are responsible for the progression of this disease but the precise mechanism and contributions from single cell remain largely unknown. Mesenchymal stem cells (MSC) are an important cellular component of the BM: they support MM growth by increasing its survival and chemo-resistance, but little is known about the paracrine signaling pathways. Three-dimensional (3D) models of MM-MSC paracrine interactions are much more biologically-relevant than simple 2D models and are considered essential for detailed studies of MM pathogenesis. Herein we present a novel 3D co-culture model designed to mimic the paracrine interaction between MSC and MM cells. MSC were embedded within a previously characterized thermoresponsive block copolymer worm gel that can induce stasis in human pluripotent stem cells (hPSC) and then co-cultured with MM cells. Transcriptional phenotyping of co-cultured cells indicated the dysregulation of genes that code for known disease-relevant factors, and also revealed IL-6 and IL-10 as upstream regulators. Importantly, we have identified a synergistic paracrine signaling pathway between IL-6 and IL-10 that plays a critical role in sustaining MM cell proliferation. Our findings indicate that this 3D co-culture system is a useful model to investigate the paracrine interaction between MM cells and the BM microenvironment in vitro. This approach has revealed a new mechanism that promotes the proliferation of MM cells and suggested a new therapeutic target

ELASTIN-LIKE RECOMBINAMERS FOR MULTI-MODAL DRUG DELIVERY SYSTEMS

Elastin is a protein with a key role in most of mammalian tissues and it is widely expressed in the extracellular matrix present over myocardium, cartilage and skin. Its elastogenic activity relies on the main cellular components of the tissue network, for instance, endothelial cells, fibroblasts, chondrocytes, and keratinocytes [1]. Nevertheless, the human elastin is naturally synthesized in early age, leading to a drawback based on the low availability, due to the stop in the natural synthetic mechanism with ageing. A clever strategy to overcome such an issue is based on the development of genetically-engineered elastin-mimicking peptides fabrication, so-called elastin-like recombinamers (ELRs), thus balancing the low availability of natural elastin and tuning the biomaterial structuring and behaviour. Relevant advances in the field can derive from the investigation of the morphological, mechanical, in-vitro and delivery-related properties of ELRs-based systems, fabricated in the form of either hydrogel or microspheres. Different scaffold constructs are studied herein, i.e., microspheres, hydrogel and microsphere integrated hydrogel in order to assess their delivery suitability and thoroughly understand the hierarchical complex structuring of the elastin-like recombinamer self- assembly mechanisms. We used two ELRs (1-HRGD6-cyclooctyne, 2-REDV-N3) modified with the two different reactive groups needed to form hydrogels via a click reaction and functionalized with two different bioactive sequences RGD and REDV that would promote cell adhesion. In this study the most stable and optimal concentration ratio of ELRs based hollow spheres exhibited no reduction in cellular metabolic activity. The sacrificial template-based method allowed us to engineer hollow spheres with a first layer of the ELRs HRGD6-component followed by a second layer of the ELRs REDV-component, by means of copper free click-chemistry reaction. The ELRs hollow spheres-tethered ELRs hydrogel was prepared by adding the pre-fabricated ELRs hollow spheres. The hydrogel construct was characterized by rheology, NMR, and Synchrotron Radiation SAXS (SRSAXS). Hollow spheres were characterized by TEM, SEM, DLS and FT-IR. Drug upload and release were assessed by means of ELISA, confocal microscopy and all constructs were successfully tested for cell metabolic activity, revealing no cytotoxicity. ELR-based hollow microspheres were fabricated and successfully entrapped into an ELR- hydrogel matrix. Release studies have been performed, determining the ELRs platform suitability as drug delivery system

The Impact of Long-Term Exposure to Space Environment on Adult Mammalian Organisms: A Study on Mouse Thyroid and Testis

Hormonal changes in humans during spaceflight have been demonstrated but the underlying mechanisms are still unknown. To clarify this point thyroid and testis/epididymis, both regulated by anterior pituitary gland, have been analyzed on long-term space-exposed male C57BL/10 mice, either wild type or pleiotrophin transgenic, overexpressing osteoblast stimulating factor-1. Glands were submitted to morphological and functional analysis

Tuning the hydroxyl functionality of block copolymer worm gels modulates their thermoresponsive behavior

Partial replacement of a hydroxyl-functional steric stabilizer with a poly(ethylene glycol)-based stabilizer modulates the thermoresponsive behavior of block copolymer worm gels prepared via aqueous polymerization-induced self-assembly

Studi di proteomica funzionale atti a definire i meccanismi regolatori del fattore di trascrizione Oct-4A

La tesi affronta il problema della regolazione del fattore di trascrizione Oct-4A coinvolto nel mantenimento dello stato pluripotente indifferenziato e di self-renewal delle cellule staminali. In particolare si focalizza sulla ricerca di nuovi interattori molecolari potenzialmente coinvolti nella sua regolazion

Serine 111 phosphorylation regulates OCT4A protein subcellular distribution and degradation.

Embryonic stem cell self-renewal properties are attributed to critical amounts of OCT4A, but little is known about its post-translational regulation. Sequence analysis revealed that OCT4A contains five putative ERK1/2 phosphorylation sites. Consistent with the hypothesis that OCT4A is a putative ERK1/2 substrate, we demonstrate that OCT4A interacts with ERK1/2 by using both in vitro GST pulldown and in vivo co-immunoprecipitation assays. MS analysis identified phosphorylation of OCT4A at Ser-111. To investigate the possibility that ERK1/2 activation can enhance OCT4A degradation, we analyzed endogenous ubiquitination in cells transfected with FLAG-OCT4A alone or with constitutively active MEK1 (MEK1(CA)), and we observed that the extent of OCT4 ubiquitination was clearly increased when MEK1(CA) was coexpressed and that this increase was more evident after MG132 treatment. These results suggest an increase in OCT4A ubiquitination downstream of MEK1 activation, and this could account for the protein loss observed after FGF2 treatment and MEK1(CA) transfection. Understanding and controlling the mechanism by which stem cells balance self-renewal would substantially advance our knowledge of stem cells

A Flexible FPGA/DSP Board for GNSS Receivers Design

With the recent launch of the first Galileo test satellite GIOVE-A, Europe made the first really important step towards the so-called Global Navigation Satellite System, which is already represented by the GPS and the GLONASS systems. In this context, the co-operation of these systems from the receiver point of view is going to ask the market for providing a user terminal able to deal with different signals. To achieve this target, a possible way forward goes through the study of dedicated signal processing algorithms based on Software Radio Defined principles. The paper will introduce the FPGA+DSP platform developed at the Politecnico di Torino, pointing out the advancements on the architecture design. Some results in terms of signal tracking performance will be also presented and discussed