Evaluation of an in vivo heterotopic model of osteogenic differentiation of equine bone marrow and muscle mesenchymal stem cells in fibrin glue scaffold

Reducing relapse and accelerating osteogenesis in rapid maxillary expansion using an injectable mesoporous bioactive glass/fibrin glue composite hydrogel

Rapid maxillary expansion (RME), as a common treatment for craniomaxillofacial deformity, faces the challenge of high relapse rates and unsatisfactory therapeutic effects. In this study, a standardized Sprague-Dawley (SD) rat RME model was first established with a modified expander as well as retainer design and optimized anterior maxillary expanding force of 100 g which exerted the most synchronized mobility of mid-palatal suture and incisors. Via the standardized model, the high relapse rate was proven to be attributed to insufficient osteogenesis in expanded suture, requiring long-term retainer wearing in clinical situations. To reduce the relapse rate, mesoporous bioactive glass/fibrin glue (MBG/FG) composite hydrogels were developed for an in situ minimal invasive injection that enhance osteogenesis in the expanded palate. The component of 1 wt% MBG was adopted for enhanced mechanical strength, matched degradation rate and ion dissolution, excellent in vitro biocompatibility and osteoinductivity. Effects of 1%MBG/FG composite hydrogel on osteogenesis in expanded mid-palatal sutures with/without retention were evaluated in the standardized model. The results demonstrated that injection of 1%MBG/FG composite hydrogel significantly promoted bone formation within the expanded mid-palatal suture, inhibited osteoclastogenesis and benefited the balance of bone remodeling towards osteogenesis. Combination of retainer and injectable biomaterial was demonstrated as a promising treatment to reduce relapse rate and enhance osteogenesis after RME. The model establishment and the composite hydrogel development in this article might provide new insight to other craniomaxillofacial deformity treatment and design of bone-repairing biomaterials with higher regenerative efficiency.

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A standardized rat RME model was established with optimized parameters.

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Sufficient osteogenesis was the prerequisite of reducing relapse ratio.

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Design of an injectable MBG/FG composite hydrogel for osteogenic enhancement.

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Combinatory treatment of injection and retention was developed for relapse reduction.

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.

Therapeutic mesenchymal stromal stem cells: Isolation, characterization and role in equine regenerative medicine and metabolic disorders

Mesenchymal stromal cells (MSC) have become a popular treatment modality in equine orthopaedics. Regenerative therapies are especially interesting for pathologies like complicated tendinopathies of the distal limb, osteoarthritis, osteochondritis dissecans (OCD) and more recently metabolic disorders. Main sources for MSC harvesting in the horse are bone marrow, adipose tissue and umbilical cord blood. While the acquisition of umbilical cord blood is fairly easy and non-invasive, extraction of bone marrow and adipose tissue requires more invasive techniques. Characterization of the stem cells as a result of any isolation method, is also a crucial step for the confirmation of the cells' stemness properties; thus, three main characteristics must be fulfilled by these cells, namely: adherence, expression of a series of well-defined differentiation clusters as well as pluripotency. EVs, resulting from the paracrine action of MSCs, also play a key role in the therapeutic mechanisms mediated by stem cells; MSC-EVs are thus largely implicated in the regulation of proliferation, maturation, polarization and migration of various target cells. Evidence that EVs alone represent a complex network 0involving different soluble factors and could then reflect biophysical characteristics of parent cells has fuelled the importance of developing highly specific techniques for their isolation and analysis. All these aspects related to the functional and technical understanding of MSCs will be discussed and summarized in this review.

Regenerative Medicine for Equine Musculoskeletal Diseases

Simple Summary

Lameness due to musculoskeletal disease is the most common diagnosis in equine veterinary practice. Many of these orthopaedic disorders are chronic problems, for which no clinically satisfactory treatment exists. Thus, high hopes are pinned on regenerative medicine, which aims to replace or regenerate cells, tissues, or organs to restore or establish normal function. Some regenerative medicine therapies have already made their way into equine clinical practice mainly to treat tendon injures, tendinopathies, cartilage injuries and degenerative joint disorders with promising but diverse results. This review summarises the current knowledge of commonly used regenerative medicine treatments and critically discusses their use.

Abstract

Musculoskeletal injuries and chronic degenerative diseases commonly affect both athletic and sedentary horses and can entail the end of their athletic careers. The ensuing repair processes frequently do not yield fully functional regeneration of the injured tissues but biomechanically inferior scar or replacement tissue, causing high reinjury rates, degenerative disease progression and chronic morbidity. Regenerative medicine is an emerging, rapidly evolving branch of translational medicine that aims to replace or regenerate cells, tissues, or organs to restore or establish normal function. It includes tissue engineering but also cell-based and cell-free stimulation of endogenous self-repair mechanisms. Some regenerative medicine therapies have made their way into equine clinical practice mainly to treat tendon injures, tendinopathies, cartilage injuries and degenerative joint disorders with promising results. However, the qualitative and quantitative spatiotemporal requirements for specific bioactive factors to trigger tissue regeneration in the injury response are still unknown, and consequently, therapeutic approaches and treatment results are diverse. To exploit the full potential of this burgeoning field of medicine, further research will be required and is ongoing. This review summarises the current knowledge of commonly used regenerative medicine treatments in equine patients and critically discusses their use.

Platelet-rich plasma enhances the repair capacity of muscle-derived mesenchymal stem cells to large humeral bone defect in rabbits

Mesenchymal stem cell-based therapy is a highly attractive strategy that promotes bone tissue regeneration. The aim of the present study was to evaluate the combination effect of muscle-derived mesenchymal stem cells (M-MSCs) and platelet-rich plasma (PRP) on bone repair capacity in rabbits with large humeral bone defect. Precise cylindrical bone defects of 10 mm diameter and 5 mm depth were established in rabbit humeral bones, which were unable to be repaired under natural conditions. The rabbits received treatment with M-MSCs/PRP gel, M-MSCs gel, or PRP gel, or no treatment. The bone tissue regeneration was evaluated at day 0-90 after surgery by HE morphological staining, Lane-Sandhu histopathological scoring, tetracycline detection, Gomori staining and micro-computed tomography. Beyond that, Transwell assay, CCK8 assay, Western blot analysis and ALP activity detection were performed in M-MSCs in vitro with or without PRP application to detect the molecular effects of PRP on M-MSCs. We found that the repair effect of M-MSCs group or PRP group was limited and the bone defects were not completely closed at post-operation 90 d. In contrast, M-MSCs/PRP group received obvious filling in the bone defects with a Lane-Sandhu evaluation score of 9. Tetracycline-labeled new bone area in M-MSCs/PRP group and new mineralized bone area were significantly larger than that in other groups. Micro-computed tomography result of M-MSCs/PRP group displayed complete recovery of humeral bone at post-operation 90 d. Further in vitro experiment revealed that PRP significantly induced migration, enhanced the growth, and promoted the expression of Cbfa-1 and Coll I in M-MSCs. In conclusion, PRP application significantly enhanced the regeneration capacity of M-MSCs in large bone defect via promoting the migration and proliferation of M-MSCs, and also inducing the osteogenic differentiation.

Journey into Bone Models: A Review

Bone is a complex tissue with a variety of functions, such as providing mechanical stability for locomotion, protection of the inner organs, mineral homeostasis and haematopoiesis. To fulfil these diverse roles in the human body, bone consists of a multitude of different cells and an extracellular matrix that is mechanically stable, yet flexible at the same time. Unlike most tissues, bone is under constant renewal facilitated by a coordinated interaction of bone-forming and bone-resorbing cells. It is thus challenging to recreate bone in its complexity in vitro and most current models rather focus on certain aspects of bone biology that are of relevance for the research question addressed. In addition, animal models are still regarded as the gold-standard in the context of bone biology and pathology, especially for the development of novel treatment strategies. However, species-specific differences impede the translation of findings from animal models to humans. The current review summarizes and discusses the latest developments in bone tissue engineering and organoid culture including suitable cell sources, extracellular matrices and microfluidic bioreactor systems. With available technology in mind, a best possible bone model will be hypothesized. Furthermore, the future need and application of such a complex model will be discussed.

[Construction of injectable tissue engineered adipose tissue with fibrin glue scaffold and human adipose-derived stem cells transfected by lentivirus vector expressing hepatocyte growth factor]

Objective

To discuss the possibility of constructing injectable tissue engineered adipose tissue, and to provide a new approach for repairing soft tissue defects.

Methods

Human adipose-derived stem cells (hADSCs) were extracted from the lipid part of human liposuction aspirate by enzymatic digestion and identified by morphological observation, flow cytometry, and adipogenic induction. The hADSCs underwent transfection by lentivirus vector expressing hepatocyte growth factor and green fluorescent protein (HGF-GFP-LVs) of different multiplicity of infection (MOI, 10, 30, 50, and 100), the transfection efficiency was calculated to determine the optimum MOI. The hADSCs transfected by HGF-GFP-LVs of optimal MOI and being adipogenic inducted were combined with injectable fibrin glue scaffold, and were injected subcutaneously into the right side of the low back of 10 T-cell deficiency BALB/c female nude mice (transfected group); non-HGF-GFP-LVs transfected hADSCs (being adipogenic inducted) combined with injectable fibrin glue scaffold were injected subcutaneously into the left side of the low back (untransfected group); and injectable fibrin glue scaffold were injected subcutaneously into the middle part of the neck (blank control group); 0.4 mL at each point. Twelve weeks later the mice were killed and the implants were taken out. Gross observation, wet weight measurement, HE staining, GFP fluorescence labeling, and immunofluorescence staining were performed to assess the in vivo adipogenic ability of the seed cells and the neovascularization of the grafts.

Results

The cultured cells were identified as hADSCs. Poor transfection efficiency was observed in MOI of 10 and 30, the transfection efficiency of MOI of 50 and 100 was more than 80%, so the optimum MOI was 50. Adipose tissue-like new-born tissues were found in the injection sites of the transfected and untransfected groups after 12 weeks of injection, and no new-born tissues was found in the blank control group. The wet-weight of new-born tissue in the transfected group [(32.30±4.06) mg] was significantly heavier than that of the untransfected group [(25.27±3.94) mg] ( t=3.929, P=0.001). The mature adipose cells in the transfected group [(126.93±5.36) cells/field] were significantly more than that in the untransfected group [(71.36±4.52) cells/field] ( t=30.700, P=0.000). Under fluorescence microscopy, some of the single cell adipocytes showed a network of green fluorescence, indicating the presence of GFP labeled exogenous hADSCs in the tissue. The vascular density of new-born tissue of the transfected group [(16.37±2.76)/field] was significantly higher than that of the untransfected group [(9.13±1.68)/field] ( t=8.678, P=0.000).

Conclusion

The hADSCs extracted from the lipid part after liposuction can be used as seed cells. After HGF-GFP-LVs transfection and adipose induction, the hADSCs combined with injectable fibrin glue scaffold can construct mature adipose tissue in vivo, which may stimulate angiogenesis, and improve retention rate of new-born tissue.

A review of fibrin and fibrin composites for bone tissue engineering

Tissue engineering has emerged as a new treatment approach for bone repair and regeneration seeking to address limitations associated with current therapies, such as autologous bone grafting. While many bone tissue engineering approaches have traditionally focused on synthetic materials (such as polymers or hydrogels), there has been a lot of excitement surrounding the use of natural materials due to their biologically inspired properties. Fibrin is a natural scaffold formed following tissue injury that initiates hemostasis and provides the initial matrix useful for cell adhesion, migration, proliferation, and differentiation. Fibrin has captured the interest of bone tissue engineers due to its excellent biocompatibility, controllable biodegradability, and ability to deliver cells and biomolecules. Fibrin is particularly appealing because its precursors, fibrinogen, and thrombin, which can be derived from the patient's own blood, enable the fabrication of completely autologous scaffolds. In this article, we highlight the unique properties of fibrin as a scaffolding material to treat bone defects. Moreover, we emphasize its role in bone tissue engineering nanocomposites where approaches further emulate the natural nanostructured features of bone when using fibrin and other nanomaterials. We also review the preparation methods of fibrin glue and then discuss a wide range of fibrin applications in bone tissue engineering. These include the delivery of cells and/or biomolecules to a defect site, distributing cells, and/or growth factors throughout other pre-formed scaffolds and enhancing the physical as well as biological properties of other biomaterials. Thoughts on the future direction of fibrin research for bone tissue engineering are also presented. In the future, the development of fibrin precursors as recombinant proteins will solve problems associated with using multiple or single-donor fibrin glue, and the combination of nanomaterials that allow for the incorporation of biomolecules with fibrin will significantly improve the efficacy of fibrin for numerous bone tissue engineering applications.

Amniotic fluid-derived stem cells mixed with platelet rich plasma for restoration of rat alveolar bone defect

Stem cells isolated from the amniotic fluid have been shown as a promising candidate for cell therapy and tissue engineering. However, the experimental and preclinical applications of amniotic fluid-derived stem cells (AFSCs) in the very field of maxillofacial bone tissue engineering are still limited. In this study, rat AFSCs were successfully harvested and characterized in vitro. The rat AFSCs showed typical fibroblastoid morphology, stable proliferation activity and multi-differentiation potential. Flow-cytometry analysis demonstrated that these cells were positive for CD29, CD44, and CD90, while negative for hematopoietic markers such as CD34 and CD45. The regenerative performance of AFSCs-premixed with platelet rich plasma (PRP) gel in restoration of alveolar bone defect was further investigated using a modified rat maxillary alveolar defect model. Micro-computer tomography and histological examination showed a superior regenerative capacity of AFSCs-premixed with PRP gel at both 4 and 8 weeks after operation comparing with control groups. Moreover, the implanted AFSCs can survive in the defect site and directly participate in the bone tissue regeneration. Taken together, these results indicated the feasibility of an AFSCs-based alveolar bone tissue engineering strategy for alveolar defect restoration.

Transplantation of tendon-derived stem cells pre-treated with connective tissue growth factor and ascorbic acid in vitro promoted better tendon repair in a patellar tendon window injury rat model

BACKGROUND AIMS

Treatment of tendon-derived stem cells (TDSCs) with connective tissue growth factor (CTGF) and ascorbic acid promoted their tenogenic differentiation. We investigated the effects of TDSCs pre-treated with CTGF and ascorbic acid on tendon repair in a patellar tendon window injury rat model.

METHODS

Green fluorescent protein-TDSCs (GFP-TDSCs) were pre-treated with or without CTGF and ascorbic acid for 2 weeks before transplantation. The patellar tendons of rats were injured and divided into three groups: fibrin glue-only group (control group), untreated and treated TDSC group. The rats were followed up until week 16.

RESULTS

The treated TDSCs accelerated and enhanced the quality of tendon repair compared with untreated TDSCs up to week 8, which was better than that in the controls up to week 16 as shown by histology, ultrasound imaging and biomechanical test. The fibrils in the treated TDSC group showed better alignment and larger size compared with those in the control group at week 8 (P = 0.004). There was lower risk of ectopic mineralization after transplantation of treated or untreated TDSCs (all P ≤ 0.050). The transplanted cells proliferated and could be detected in the window wound up to weeks 2 to 4 and week 8 for the untreated and treated TDSC groups, respectively.

CONCLUSIONS

The transplantation of TDSCs promoted tendon repair up to week 16, with CTGF and ascorbic acid pre-treatment showing the best results up to week 8. Pre-treatment of TDSCs with CTGF and ascorbic acid may be used to further enhance the rate and quality of tendon repair after injury.

Effect of collagen sponge and fibrin glue on bone repair

The ability of hemostatic agents to promote bone repair has been investigated using in vitro and in vivo models but, up to now, the results are inconclusive.

Osteoinduction of bone grafting materials for bone repair and regeneration

Regeneration of bone defects caused by trauma, infection, tumours or inherent genetic disorders is a clinical challenge that usually necessitates bone grafting materials. Autologous bone or autograft is still considered the clinical "gold standard" and the most effective method for bone regeneration. However, limited bone supply and donor site morbidity are the most important disadvantages of autografting. Improved biomaterials are needed to match the performance of autograft as this is still superior to that of synthetic bone grafts. Osteoinductive materials would be the perfect candidates for achieving this task. The aim of this article is to review the different groups of bone substitutes in terms of their most recently reported osteoinductive properties. The different factors influencing osteoinductivity by biomaterials as well as the mechanisms behind this phenomenon are also presented, showing that it is very limited compared to osteoinductivity shown by bone morphogenetic proteins (BMPs). Therefore, a new term to describe osteoinductivity by biomaterials is proposed. Different strategies for adding osteoinductivity (BMPs, stem cells) to bone substitutes are also discussed. The overall objective of this paper is to gather the current knowledge on osteoinductivity of bone grafting materials for the effective development of new graft substitutes that enhance bone regeneration.