Periodontal tissue regeneration with PRP incorporated gelatin hydrogel sponges

Synthesis and Modification of Gelatin Methacryloyl (GelMA) with Antibacterial Quaternary Groups and Its Potential for Periodontal Applications

Gelatin methacryloyl (GelMA) hydrogels have been widely used for different biomedical applications due to their tunable physical characteristics and appropriate biological properties. In addition, GelMA could be modified with the addition of functional groups providing inherent antibacterial capabilities. Here, GelMA-based hydrogels were developed through the combination of a GelMA unmodified and modified polymer with quaternary ammonium groups (GelMAQ). The GelMAQ was synthesized from GelMA with a low degree of substitution of methacrylamide groups (DSMA) and grafted with glycidyltrimethylammonium chloride in the free amine groups of the lysine moieties present in the original gelatin. GelMAs with high DSMA and GelMAQ were combined 50/50% or 25/75% (w/w), respectively, and compared to controls GelMA and GelMA with added chlorhexidine (CHX) at 0.2%. The different hydrogels were characterized using 1H-NMR spectroscopy and swelling behavior and tested in (1) Porphyromonas gingivalis to evaluate their antibacterial properties and (2) human gingival fibroblast to evaluate their cell biocompatibility and regenerative properties. GelMA/GelMAQ 25/75% showed good antibacterial properties but also excellent biocompatibility and regenerative properties toward human fibroblasts in the wound healing assay. Taken together, these results suggest that the modification of GelMA with quaternary groups could facilitate periodontal tissue regeneration, with good biocompatibility and added antibacterial properties.

Tissue Engineering for Periodontal Ligament Regeneration: Biomechanical Specifications

The periodontal biomechanical environment is very difficult to investigate. By the complex geometry and composition of the periodontal ligament (PDL), its mechanical behavior is very dependent on the type of loading (compressive versus tensile loading; static versus cyclic loading; uniaxial versus multiaxial) and the location around the root (cervical, middle, or apical). These different aspects of the PDL make it difficult to develop a functional biomaterial to treat periodontal attachment due to periodontal diseases. This review aims to describe the structural and biomechanical properties of the PDL. Particular importance is placed in the close interrelationship that exists between structure and biomechanics: the PDL structural organization is specific to its biomechanical environment, and its biomechanical properties are specific to its structural arrangement. This balance between structure and biomechanics can be explained by a mechanosensitive periodontal cellular activity. These specifications have to be considered in the further tissue engineering strategies for the development of an efficient biomaterial for periodontal tissues regeneration.

Liquid platelet-rich fibrin promotes the regenerative potential of human periodontal ligament cells

OBJECTIVE

To compare the biological effect of PRP and liquid-PRF on human periodontal ligament cells (hPDLCs) in vitro.

METHODS

The liquid-PRF was processed with centrifugation at 700 g for 3 min, and PRP was processed according to Curasan's protocol. Migration and proliferation assay were performed by a scratch/Transwell assay and a CCK-8 assay, respectively. To investigate hPDLC differentiation, alkaline phosphatase (ALP) assay, Alizarin Red S staining, and gene expression level detection of Runx2, Col1a1, and OCN were conducted. Furthermore, cells cultured with lipopolysaccharide (LPS) to induce an inflammation condition were utilized to investigate the impact of liquid-PRF on inflammatory resolution.

RESULTS

Either PRP or liquid-PRF can promote proliferation, migration of hPDLCs, and osteogenic differentiation of hPDLCs. It was noteworthy that liquid-PRF demonstrated a significantly higher ability to promote the biological differentiation and mineralization of hPDLCs compared with PRP. Lastly, when hPDLCs were incubated with LPS, cells cultured with liquid-PRF showed significantly lower mRNA expression levels of inflammatory genes.

CONCLUSIONS

Liquid-PRF notably promoted hPDLC activity and attenuated the inflammatory state induced by LPS.

Bone Regeneration of Osteoporotic Vertebral Body Defects Using Platelet-Rich Plasma and Gelatin β-Tricalcium Phosphate Sponges

The objective of the present study was to investigate the effect of platelet-rich plasma (PRP) combined with gelatin β-tricalcium phosphate (β-TCP) sponge on bone generation in a lumbar vertebral body defect of ovariectomized rat. After creating critical-size defects in the center of the anterior vertebral body, the defects were filled with the following materials: (1) no material (control group), (2) gelatin β-TCP sponge with PRP (PRP sponge group), and (3) gelatin β-TCP sponge with phosphate-buffered saline (PBS sponge group). Microcomputed tomography and histological evaluation were performed immediately after surgery and at 4, 8, and 12 weeks to assess bone regeneration. Biomechanical test was also performed at postoperative week 12. In the PRP sponge group, both imaging and histological examination showed that visible osteogenesis was first induced and additional growth of bone tissue was observed in the transplanted sponge, compared with the PBS sponge group. There was no negative effect of either PRP sponge or PBS sponge transplantation on bone tissue generation around the periphery of the defect. Biomechanical test showed increased stiffness of the affected vertebral bodies in the PRP sponge group. These results indicate that PRP-impregnated gelatin β-TCP sponge is effective for facilitating bone regeneration in lumbar vertebral bone defect under osteoporotic condition. PRP combined with gelatin β-TCP sponges could be potentially useful for developing a new approach to vertebroplasty for osteoporotic vertebral fracture.

Blood derivatives awaken in regenerative medicine strategies to modulate wound healing

Blood components play key roles in the modulation of the wound healing process and, together with the provisional fibrin matrix ability to selectively bind bioactive molecules and control its spatial-temporal presentation, define the complex microenvironment that characterize this biological process. As a biomimetic approach, the use of blood derivatives in regenerative strategies has awakened as a source of multiple therapeutic biomolecules. Nevertheless, and despite their clinical relevance, blood derivatives have been showing inconsistent therapeutic results due to several factors, including proper control over their delivery mechanisms. Herein, we highlight recent trends on the use biomaterials to protect, sequester and deliver these pools of biomolecules in tissue engineering and regenerative medicine approaches. Particular emphasis is given to strategies that enable to control their spatiotemporal delivery and improve the selectivity of presentation profiles of the biomolecules derived from blood derivatives rich in platelets. Finally, we discussed possible directions for biomaterials design to potentiate the aimed regenerative effects of blood derivatives and achieve efficient therapies.

Contributions of Bioactive Molecules in Stem Cell-Based Periodontal Regeneration

Periodontal disease is a widespread disease, which without proper treatment, may lead to tooth loss in adults. Because stem cells from the inflammatory microenvironment created by periodontal disease exhibit impaired regeneration potential even under favorable conditions, it is difficult to obtain satisfactory therapeutic outcomes using traditional treatments, which only focus on the control of inflammation. Therefore, a new stem cell-based therapy known as cell aggregates/cell sheets technology has emerged. This approach provides sufficient numbers of stem cells with high viability for treating the defective site and offers new hope in the field of periodontal regeneration. However, it is not sufficient for regenerating periodontal tissues by delivering cell aggregates/cell sheets to the impaired microenvironment in order to suppress the function of resident cells. In the present review, we summarize some promising bioactive molecules that act as cellular signals, which recreate a favorable microenvironment for tissue regeneration, recruit endogenous cells into the defective site and enhance the viability of exogenous cells.

Engineered scaffolds and cell-based therapy for periodontal regeneration

BACKGROUND

The main objective of regenerative periodontal therapy is to completely restore the periodontal tissues lost. This review summarizes the most recent evidence in support of scaffold- and cell-based tissue engineering, which are expected to play a relevant role in next-generation periodontal regenerative therapy.

METHODS

A literature search (PubMed database) was performed to analyze more recently updated articles regarding periodontal regeneration, scaffolds and cell-based technologies.

RESULTS

Evidence supports the importance of scaffold physical cues to promote periodontal regeneration, including scaffold multicompartmentalization and micropatterning. The in situ delivery of biological mediators and/or cell populations, both stem cells and already differentiated cells, has shown promising in vivo efficacy.

CONCLUSIONS

Porous scaffolds are pivotal for clot stabilization, wound compartmentalization, cell homing and cell nutrients delivery. Given the revolutionary introduction of rapid prototyping technique and cell-based therapies, the fabrication of custom-made scaffolds is not far from being achieved.

Spatiotemporal characterization of hydration process of asymmetric polymeric wound dressings for decubitus ulcers

Pressure ulcers belong to the most chalenging clinical problems. As hydration level of such wounds is important for optimal healing, preparation of new wound dressing (WD) materials for pressure ulcers requires thorough in vitro evaluation as prerequisite to final in vivo testing. The aims of the study were to: (a) develop a simple method of preparation of asymmetric polymeric membrane, (b) to propose a set of in vitro methods for membrane characterization during hydration. A polyvinyl alcohol asymmetric membrane with homogeneous skin layer and porous spongy layer was developed with nonadhesive properties and ability to absorb and retain the water. Complementary methods, including magnetic resonance imaging, allowed quantitative assessment of spatiotemporal aspects of membrane hydration, that is, global water uptake; swelling; local hydration in terms of proton density mapping; spatial distribution of T₂ relaxation time; Young's modulus; piercing resistance. The proposed method of initial wound dressing evaluation seems to be promising to compare various WD formulations, to assess the time required to prepare WD membrane to be applied to the wound and to assess how long WD retains desired working properties. The developed asymmetric membrane seems to be a good candidate for further evaluation. It was found that: Young's modulus of hydrated membrane was comparable to those of human skin; asymmetrical structure was retained during the entire hydration period; each layer had its own distinct, hydration related, properties and their spatiotemporal evolution; relatively slow changes of membrane properties during the potential WD application time-span of several hours was observed. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 843-853, 2018.