Efficacy and safety of a new heterologous fibrin biopolymer on socket bone healing after tooth extraction: An experimental pre-clinical study

AIM

To assess the efficacy of heterologous fibrin biopolymer (HFB) in promoting alveolar bone healing after tooth extraction in rats.

MATERIALS AND METHODS

The upper right incisors of 48 Wistar rats were extracted. Toothless sockets were filled with HFB (HFBG, n = 24) or blood clot (BCG, n = 24). The tooth extraction sites were subjected to micro-computed tomography (micro-CT), histological, histomorphometric and immunohistochemical (for Runt-related transcription factor 2/Runx2 and tartrate-resistant acid phosphatase/TRAP) analyses on days 0, 7, 14 and 42 after extraction.

RESULTS

Socket volume remained similar between days 0 and 14 (69 ± 5.4 mm3), except in the BCG on day 14, when it was 10% lower (p = .043). Although the number of Runx2+ osteoblasts was high and similar in both groups (34 × 102 cells/mm2), the HFBG showed lower inflammatory process and osteoclast activity than BCG at 7 days. On day 14, the number of Runx2+ osteoblasts remained high and similar to the previous period in both groups. However, osteoclast activity increased. This increase was 55% lower in the HFBG than BCG. In the BCG, the presence of an inflammatory process and larger and numerous osteoclasts on day 14 led to resorption of the alveolar bone ridge and newly formed bone. On day 42, numbers of Runx2+ osteoblast and TRAP+ osteoclasts decreased dramatically in both groups. Although the BCG exhibited a more mature cortical bone formation, it exhibited a higher socket reduction (28.3 ± 6.67%) and smaller bone volume (37 ± 5.8 mm3) compared with HFBG (socket reduction of 14.8 ± 7.14% and total bone volume of 46 ± 5.4 mm3).

CONCLUSIONS

HFB effectively suppresses osteoclast activity and reduces alveolar bone resorption compared with blood clot, thus preventing three-dimensional bone loss, particularly during the early healing period. HFB emerges as a promising biopharmaceutical material for enhancing healing processes after tooth extraction.

The use of commercial fibrin glue in dermal replacement material reduces angiogenic and lymphangiogenic gene and protein expression in vitro

BACKGROUND

Commercial fibrin glue is increasingly finding its way into clinical practice in surgeries to seal anastomosis, and initiate hemostasis or tissue repair. Human biological glue is also being discussed as a possible cell carrier. To date, there are only a few studies addressing the effects of fibrin glue on the cell-molecular level. This study examines the effects of fibrin glue on angiogenesis and lymphangiogenesis, as well as adipose-derived stem cells (ASCs) with a focus on gene and protein expression in scaffolds regularly used for tissue engineering approaches.

METHODS

Collagen-based dermal regeneration matrices (DRM) were seeded with human umbilical vein endothelial cells (HUVEC), human dermal lymphatic endothelial cells (LECs), or adipose-derived stem cells (ASC) and fixed with or without fibrin glue according to the experimental group. Cultures were maintained for 1 and 7 days. Finally, angiogenic and lymphangiogenic gene and protein expression were measured with special regard to subtypes of vascular endothelial growth factor (VEGF) and corresponding receptors using Multiplex-qPCR and ELISA assays. In addition, the hypoxia-induced factor 1-alpha (HIF1a) mediated intracellular signaling pathways were included in assessments to analyze a hypoxic encapsulating effect of fibrin polymers.

RESULTS

All cell types reacted to fibrin glue application with an alteration of gene and protein expression. In particular, vascular endothelial growth factor A (VEGFA), vascular endothelial growth factor B (VEGFB), vascular endothelial growth factor C (VEGFC), vascular endothelial growth receptor 1 (VEGFR1/FLT1), vascular endothelial growth receptor 2 (VEGFR2/KDR), vascular endothelial growth receptor 3 (VEGFR3/FLT4) and Prospero Homeobox 1 (PROX1) were depressed significantly depending on fibrin glue. Especially short-term fibrin effect led to a continuous downregulation of respective gene and protein expression in HUVECs, LECs, and ASCs.

CONCLUSION

Our findings demonstrate the impact of fibrin glue application in dermal regeneration with special regard to angiogenesis and lymphangiogenesis. In particular, a short fibrin treatment of 24 hours led to a decrease in gene and protein levels of LECS, HUVECs, and ASCs. In contrast, the long-term application showed less effect on gene and protein expressions. Therefore, this work demonstrated the negative effects of fibrin-treated cells in tissue engineering approaches and could affect wound healing during dermal regeneration.

Recent Developments and Current Applications of Organic Nanomaterials in Cartilage Repair

Regeneration of cartilage is difficult due to the unique microstructure, unique multizone organization, and avascular nature of cartilage tissue. The development of nanomaterials and nanofabrication technologies holds great promise for the repair and regeneration of injured or degenerated cartilage tissue. Nanomaterials have structural components smaller than 100 nm in at least one dimension and exhibit unique properties due to their nanoscale structure and high specific surface area. The unique properties of nanomaterials include, but are not limited to, increased chemical reactivity, mechanical strength, degradability, and biocompatibility. As an emerging nanomaterial, organic nanocomposites can mimic natural cartilage in terms of microstructure, physicochemical, mechanical, and biological properties. The integration of organic nanomaterials is expected to develop scaffolds that better mimic the extracellular matrix (ECM) environment of cartilage to enhance scaffold-cell interactions and improve the functionality of engineered tissue constructs. Next-generation hydrogel technology and bioprinting can be used not only for healing cartilage injury areas but also for extensive osteoarthritic degenerative changes within the joint. Although more challenges need to be solved before they can be translated into full-fledged commercial products, nano-organic composites remain very promising candidates for the future development of cartilage tissue engineering.

Medical Adhesives and Their Role in Laparoscopic Surgery—A Review of Literature

Laparoscopic surgery is undergoing rapid development. Replacing the traditional method of joining cut tissues with sutures or staples could greatly simplify and speed up laparoscopic procedures. This alternative could undoubtedly be adhesives. For decades, scientists have been working on a material to bond tissues together to create the best possible conditions for tissue regeneration. The results of research on tissue adhesives achieved over the past years show comparable treatment effects to traditional methods. Tissue adhesives are a good alternative to surgical sutures in wound closure. This article is a review of the most important groups of tissue adhesives including their properties and possible applications. Recent reports on the development of biological adhesives are also discussed.

Transplantation of bone marrow mesenchymal stem cells and fibrin glue into extraction socket in maxilla promoted bone regeneration in osteoporosis rat

AIMS

Bone defect repair in osteoporosis remains a tremendous challenge for clinicians due to increased bone metabolism resulted from estrogen deficiency. This study aims to investigate the effect of bone marrow mesenchymal stem cells (BMSCs) combined with fibrin glue (FG) in the extraction socket healing process of osteoporosis rats, as well as estimate the role of estrogen receptors (ERs) played in BMSCs differentiation in vitro and in the alveolar bone reconstruction process in vivo.

MAIN METHODS

Forty rats were randomly divided into four groups, under general anesthesia, three groups underwent bilateral ovariectomy(OVX) and one group with the sham operation. Three months later, the osteogenic ability of BMSCs, isolated from healthy and osteoporosis rats, respectively, was tested. The ERα and ERβ mRNA expression in BMSCs was also evaluated by RT-PCR analysis. In vivo experiment, Micro-CT detection, histological and immunofluorescent analysis, tissue PCR was conducted up to 2, 4 and 6 weeks after transplantation of BMSCs/FG to assess the newly formed bone in the extraction socket.

KEY FINDINGS

The BMSCs from osteoporosis rats displayed weaker osteogenic potential and lower ERs expression compared with the BMSCs from healthy rats. Newly formed bone tissue filled the socket defect in BMSCs/FG treated VOX rats after six weeks, which was comparable to the sham group, while reduced ERs expression was found in the regenerated bone of the OVX group.

SIGNIFICANCE

The BMSCs seeded within FG might provide an alternative therapeutic method for repairing the extraction socket defect in osteoporosis condition.

Development of Transient Recombinant Expression and Affinity Chromatography Systems for Human Fibrinogen

Fibrin forms the structural scaffold of blood clots and has great potential for biomaterial applications. Creating recombinant expression systems of fibrinogen, fibrin’s soluble precursor, would advance the ability to construct mutational libraries that would enable structure–function studies of fibrinogen and expand the utility of fibrin as a biomaterial. Despite these needs, recombinant fibrinogen expression systems, thus far, have relied on the time-consuming creation of stable cell lines. Here we present tests of a transient fibrinogen expression system that can rapidly generate yields of 8–12 mg/L using suspension HEK Expi293^TM cells. We report results from two different plasmid systems encoding the fibrinogen cDNAs and two different transfection reagents. In addition, we describe a novel, affinity-based approach to purifying fibrinogen from complex media such as human plasma. We show that using a high-affinity peptide which mimics fibrin’s knob ‘A’ sequence enables the purification of 50–75% of fibrinogen present in plasma. Having robust expression and purification systems of fibrinogen will enable future studies of basic fibrin(ogen) biology, while paving the way for the ubiquitous use of fibrin as a biomaterial.

Potential of Fibrin Glue and Mesenchymal Stem Cells (MSCs) to Regenerate Nerve Injuries: A Systematic Review

Cell-based therapy is a promising treatment to favor tissue healing through less invasive strategies. Mesenchymal stem cells (MSCs) highlighted as potential candidates due to their angiogenic, anti-apoptotic and immunomodulatory properties, in addition to their ability to differentiate into several specialized cell lines. Cells can be carried through a biological delivery system, such as fibrin glue, which acts as a temporary matrix that favors cell-matrix interactions and allows local and paracrine functions of MSCs. Thus, the aim of this systematic review was to evaluate the potential of fibrin glue combined with MSCs in nerve regeneration. The bibliographic search was performed in the PubMed/MEDLINE, Web of Science and Embase databases, using the descriptors ("fibrin sealant" OR "fibrin glue") AND "stem cells" AND "nerve regeneration", considering articles published until 2021. To compose this review, 13 in vivo studies were selected, according to the eligibility criteria. MSCs favored axonal regeneration, remyelination of nerve fibers, as well as promoted an increase in the number of myelinated fibers, myelin sheath thickness, number of axons and expression of growth factors, with significant improvement in motor function recovery. This systematic review showed clear evidence that fibrin glue combined with MSCs has the potential to regenerate nervous system lesions.

Effects of Therapy with Fibrin Glue combined with Mesenchymal Stem Cells (MSCs) on Bone Regeneration: A Systematic Review

Cell therapy strategies using mesenchymal stem cells (MSCs) carried in fibrin glue have shown promising results in regenerative medicine. MSCs are crucial for tissue healing because they have angiogenic, anti-apoptotic and immunomodulatory properties, in addition to the ability to differentiate into several specialized cell lines. Fibrin sealant or fibrin glue is a natural polymer involved in the coagulation process. Fibrin glue provides a temporary structure that favors angiogenesis, extracellular matrix deposition and cell-matrix interactions. Additionally, fibrin glue maintains the local and paracrine functions of MSCs, providing tissue regeneration through less invasive clinical procedures. Thus, the objective of this systematic review was to assess the potential of fibrin glue combined with MSCs in bone or cartilage regeneration. The bibliographic search was performed in the PubMed/MEDLINE, LILACS and Embase databases, using the descriptors (“fibrin sealant” OR “fibrin glue”) AND “stem cells” AND “bone regeneration”, considering articles published until 2021. In this case, 12 preclinical and five clinical studies were selected to compose this review, according to the eligibility criteria. In preclinical studies, fibrin glue loaded with MSCs, alone or associated with bone substitute, significantly favored bone defects regeneration compared to scaffold without cells. Similarly, fibrin glue loaded with MSCs presented considerable potential to regenerate joint cartilage injuries and multiple bone fractures, with significant improvement in clinical parameters and absence of postoperative complications. Therefore, there is clear evidence in the literature that fibrin glue loaded with MSCs, alone or combined with bone substitute, is a promising strategy for treating lesions in bone or cartilaginous tissue.

Recent advances in AFM-based biological characterization and applications at multiple levels

Atomic force microscopy (AFM) has found a wide range of bio-applications in the past few decades due to its ability to measure biological samples in natural environments at a high spatial resolution. AFM has become a key platform in biomedical, bioengineering and drug research fields, enabling mechanical and morphological characterization of live biological systems. Hence, we provide a comprehensive review on recent advances in the use of AFM for characterizing the biomechanical properties of multi-scale biological samples, ranging from molecule, cell to tissue levels. First, we present the fundamental principles of AFM and two AFM-based models for the characterization of biomechanical properties of biological samples, covering key AFM devices and AFM bioimaging as well as theoretical models for characterizing the elasticity and viscosity of biomaterials. Then, we elaborate on a series of new experimental findings through analysis of biomechanics. Finally, we discuss the future directions and challenges. It is envisioned that the AFM technique will enable many remarkable discoveries, and will have far-reaching impacts on bio-related studies and applications in the future.

The Use of Nanomaterials in Tissue Engineering for Cartilage Regeneration; Current Approaches and Future Perspectives

The repair and regeneration of articular cartilage represent important challenges for orthopedic investigators and surgeons worldwide due to its avascular, aneural structure, cellular arrangement, and dense extracellular structure. Although abundant efforts have been paid to provide tissue-engineered grafts, the use of therapeutically cell-based options for repairing cartilage remains unsolved in the clinic. Merging a clinical perspective with recent progress in nanotechnology can be helpful for developing efficient cartilage replacements. Nanomaterials, < 100 nm structural elements, can control different properties of materials by collecting them at nanometric sizes. The integration of nanomaterials holds promise in developing scaffolds that better simulate the extracellular matrix (ECM) environment of cartilage to enhance the interaction of scaffold with the cells and improve the functionality of the engineered-tissue construct. This technology not only can be used for the healing of focal defects but can also be used for extensive osteoarthritic degenerative alterations in the joint. In this review paper, we will emphasize the recent investigations of articular cartilage repair/regeneration via biomaterials. Also, the application of novel technologies and materials is discussed.

Stem-cell-based therapies to enhance peripheral nerve regeneration

Peripheral nerve injury remains a major cause of morbidity in trauma patients. Despite advances in microsurgical techniques and improved understanding of nerve regeneration, obtaining satisfactory outcomes after peripheral nerve injury remains a difficult clinical problem. There is a growing body of evidence in preclinical animal studies demonstrating the supportive role of stem cells in peripheral nerve regeneration after injury. The characteristics of both mesoderm-derived and ectoderm-derived stem cell types and their role in peripheral nerve regeneration are discussed, specifically focusing on the presentation of both foundational laboratory studies and translational applications. The current state of clinical translation is presented, with an emphasis on both ethical considerations of using stems cells in humans and current governmental regulatory policies. Current advancements in cell-based therapies represent a promising future with regard to supporting nerve regeneration and achieving significant functional recovery after debilitating nerve injuries.

Challenges for Natural Hydrogels in Tissue Engineering

Protein-based biopolymers derived from natural tissues possess a hierarchical structure in their native state. Strongly solvating, reducing and stabilizing agents, as well as heat, pressure, and enzymes are used to isolate protein-based biopolymers from their natural tissue, solubilize them in aqueous solution and convert them into injectable or preformed hydrogels for applications in tissue engineering and regenerative medicine. This review aims to highlight the need to investigate the nano-/micro-structure of hydrogels derived from the extracellular matrix proteins of natural tissues. Future work should focus on identifying the nature of secondary, tertiary, and higher order structure formation in protein-based hydrogels derived from natural tissues, quantifying their composition, and characterizing their binding pockets with cell surface receptors. These advances promise to lead to wide-spread use of protein-based hydrogels derived from natural tissues as injectable or preformed matrices for cell delivery in tissue engineering and regenerative medicine.