Role of bone morphogenetic proteins in periodontal tissue engineering: Relatively unexplored horizon

Tissue engineering aims to reconstruct the natural target tissue by a combination of three key elements stem/progenitor cells (that will create the new tissue), signaling molecules (that instruct the cells to form the desired tissue) scaffold/extracellular matrix (to hold the cells). Regeneration of the periodontal tissues following destructive episodes of various forms of periodontitis is a formidable challenge to periodontologists. Bone morphogenic proteins have been considered as the most potent growth factors that can promote the bone regeneration. This review will emphasize on the unique nature of the tissue engineered bone morphogenic proteins molecules regarding their structure, classification, signaling mechanism, etc. which will further help in understanding their role and potential advances necessary to facilitate the process of regeneration in the field of periodontics.

Fabrication of Graphene Oxide Aerogel to Repair Neural Tissue

: The neural tissue engineering has been designed as a subset of tissue engineering for treating congenital malformations and accident injuries, particularly for individuals requiring tissue grafting. Such transplants, usually performed as autografting, can often not meet the requirements of an effective scaffold used in nerve tissue engineering. A novel neural tissue scaffold was introduced here to solve the problem concerning the reduced graphene oxide. The three-dimensional graphene oxide in the neural canal restricts the formation of fibroglandular tissues and facilities neural stem cell proliferation and growth. In these techniques, graphene oxide aerogel was initially made. Then, the freeze-drying process was used to fix the geometry of reduced graphene oxide hydrogels prepared using graphene oxide dispersion and ethylenediamine and gain aerogels. The X-ray diffraction patterns, FTIR and morphological related to samples were examined, followed by conducting in-vitro micropropagation and 4, 6-diamidino-2-phenylindol (DAPI) staining in fibroblast and P19 cultures. The results from immunofluorescence staining demonstrated the neural differentiation of P19 cells. It can be concluded that most cells attached to and differentiated on the scaffold surface and axons can penetrate randomly through them. Finally, the three-dimensional graphene oxide was proposed as an ideal alternative to be used in neural tissue engineering.

P029 HOW DOES THE MADRID APPROACH WORK

Aim The Madrid APPROACH is the combination of an absorbable mesh and a permanent retromuscular mesh for the treatment of the complex abdominal wall problems. It has been controversial because of the need of two different meshes. We present a clinic case to show the utility of this technique and how it allows rebuilding the inguinal ligament. Material and Methods 78 years old woman who underwent a right ilioinguinal and obturatriz lymphadenectomy due to a melanoma. Incisional hernia fixed in 2018 with a retromuscular polyester mesh. New incisional iliac hernia (L3) over the right iliac vessels, with an absence of inguinal ligament, right rectus atrophy, and the previous mesh being part of the sac. Surgery: incision over the previous scar. Wide dissection of the preperitoneal space, Retzius space and lateral to the cuadratus lumborum, retrodiafragmatic dissection, lateral transverse abdominus release, and cross-over to the retrorectal left space. Preperitoneal BioA mesh and an upper 40x40cm medium weight polipropilene mesh set to both Cooper ligaments. Results After two and a half months, a PET-TC showed the BioA mesh perfectly adapted to the abdominal wall and rebuilt a new inguinal ligament. Also intense FDG capitation of the mesh due to the high cellular metabolism. Two years later the patient has a continent abdominal wall, the follow up TC shows the disappearance of the absorbable mesh and the perfect abdominal wall rebuilt. Conclusions The BioA mesh acts like a tissue scaffold for new conjunctive tissue as we see the intense FDG captation. The Madrid APPROACH allows giving response to very complex abdominal wall problems.

Nano Iron Oxide-PCL Composite as an Improved Soft Tissue Scaffold

Iron oxide nanoparticles were employed to fabricate a soft tissue scaffold with enhanced physicochemical and biological characteristics. Growth promotion effect of L-lysine coated magnetite (Lys@Fe3O4) nanoparticles on the liver cell lines was proved previously. So, in the current experiment these nanoparticles were employed to fabricate a soft tissue scaffold with growth promoting effect on the liver cells. Lys@Fe3O4 nanoparticles were synthesized via co-precipitation reaction. Resulted particles were ~7 nm in diameter and various concentrations (3, 5, and 10 wt%) of these nanoparticles were used to fabricate nanocomposite PCL fibers. Electrospinning technique was employed and physicochemical characteristics of the resulted nanofibers were evaluated. Electron micrographs and EDX-mapping analysis showed that nanoparticles were well dispersed in the PCL fibers and no bead structure were formed. As expected, incorporation of Lys@Fe3O4 to the PCL nanofibers resulted in a reduction in hydrophobicity of the scaffold. Nanocomposite scaffolds were shown increased tensile strength with increasing concentration of employed nanoparticles. In contrast to PCL scaffold, nearly 150% increase in the cell viability was observed after 3-days exposure to the nanocomposite scaffolds. This study indicates that incorporation of magnetite nanoparticles in the PCL fibers make them more prone to cell attachment. However, incorporated nanoparticles can provide the attached cells with valuable iron element and consequently promote the cells growth rate. Based on the results, magnetite enriched PCL nanofibers could be introduced as a scaffold to enhance the biological performance for liver tissue engineering purposes.

The Use of Collagen with High Concentration in Cartilage Tissue Engineering by Means of 3D-Bioprinting

3D-bioprinting is a promising technology for a tissue scaffold fabrication in the case of damaged tissue/organ replacement. Collagen is one of the most appropriate hydrogel for the purpose, due to its exceptional biocompatibility. However, the use of collagen with conventionally low concentration makes bioprinting process difficult and does not provide its high accuracy. The purpose of the study was evaluation of suitability of collagen with high concentration in case of chondrocyte-laden scaffold fabrication via 3D-bioprinting for cartilage regeneration in vitro and in vivo. The results of the study showed that inherent porosity of 4% collagen was not enough for cell survival in the case of long-term incubation in vitro. With the beginning of the scaffold incubation, cell migration to the surface and out of the scaffold was observed. The residual cells died mostly within 4 weeks. As for in vivo study, in 2 weeks after implantation of the scaffold, a weak granulomatous inflammation was observed. In 6 weeks, a connective tissue was formed in the area of implantation. In the tissue, macrophages and groups of small cells with round nuclei were found. In accordance with morphological criteria, these cells could be considered as young chondrocytes. However, its amount was not enough to initiate the formation of cartilage.

Fabrication of Soft Tissue Scaffold-Mimicked Microelectrode Arrays Using Enzyme-Mediated Transfer Printing

Hydrogels are the ideal materials in the development of implanted bioactive neural interfaces because of the nerve tissue-mimicked physical and biological properties that can enhance neural interfacing compatibility. However, the integration of hydrogels and rigid/dehydrated electronic microstructure is challenging due to the non-reliable interfacial bonding, whereas hydrogels are not compatible with most conditions required for the micromachined fabrication process. Herein, we propose a new enzyme-mediated transfer printing process to design an adhesive biological hydrogel neural interface. The donor substrate was fabricated via photo-crosslinking of gelatin methacryloyl (GelMA) containing various conductive nanoparticles (NPs), including Ag nanowires (NWs), Pt NWs, and PEDOT:PSS, to form a stretchable conductive bioelectrode, called NP-doped GelMA. On the other hand, a receiver substrate composed of microbial transglutaminase-incorporated gelatin (mTG-Gln) enabled simultaneous temporally controlled gelation and covalent bond-enhanced adhesion to achieve one-step transfer printing of the prefabricated NP-doped GelMA features. The integrated hydrogel microelectrode arrays (MEA) were adhesive, and mechanically/structurally bio-compliant with stable conductivity. The devices were structurally stable in moisture to support the growth of neuronal cells. Despite that the introduction of AgNW and PEDOT:PSS NPs in the hydrogels needed further study to avoid cell toxicity, the PtNW-doped GelMA exhibited a comparable live cell density. This Gln-based MEA is expected to be the next-generation bioactive neural interface.

Characterization of Scleraxis and SRY-Box 9 from Adipose-Derived Stem Cells Culture Seeded with Enthesis Scaffold in Hypoxic Condition

The use of mesenchymal stem cells can add local improvements potential to enthesis tissue regeneration based on tropical activity through secretions of growth factors, cytokines, and vesicles (e.g. exosomes), collectively known as secretomes. This study aims to analyze secretomes characterization from adipose-derived mesenchymal stem cells seeded with enthesis tissue scaffold in hypoxic conditions and to analyze the influence of hypoxic environment to the characterization of secretomes. This is an in-vitro study using a Randomized Control Group Post-Test Only design. This study using Adipose Stem Cells (ASCs) were cultured in hypoxia (Oxygen 5%) and Normoxia (21%) condition. The scaffolds are fresh-frozen enthesis tissue and was seeded in the treatment group and compared to control. The evaluation of Scleraxis (Scx) and SRY-box (Sox9) was measured using ELISA on the 2nd, 4th, and 6th days. Comparison of Scx levels between each evaluation time showed a positive trend in a group with scaffold in hypoxia condition although it has no significant differences (p=0.085), with the highest level on day 6, that is 13,568 ng/ml. Conversely, the comparison of Sox9 showed significant differences (p=0.02) in a group with scaffold in hypoxia condition, with the highest level on day 4, that is 28,250 ng/ml. The use of enthesis scaffold seeded in adipose-derived mesenchymal stem cells in hypoxic conditions shows a positive trend as regenerative effort of injured enthesis tissue through Scleraxis and Sox9 secretomes induction.