Characterization, GFP gene Nucleofection, and allotransplantation in injured tendons of ovine amniotic fluid-derived stem cells

Hypoxia-Mimetic CoCl2 Agent Enhances Pro-Angiogenic Activities in Ovine Amniotic Epithelial Cells-Derived Conditioned Medium

Amniotic epithelial stem cells (AECs) are largely studied for their pro-regenerative properties. However, it remains undetermined if low oxygen (O₂) levels that AECs experience in vivo can be of value in maintaining their biological properties after isolation. To this aim, the present study has been designed to evaluate the effects of a hypoxia-mimetic agent, cobalt chloride (CoCl₂), on AECs’ stemness and angiogenic activities. First, a CoCl₂ dose-effect was performed to select the concentration able to induce hypoxia, through HIF-1α stabilization, without promoting any cytotoxicity effect assessed through the analysis of cell vitality, proliferation, and apoptotic-related events. Then, the identified CoCl₂ dose was evaluated on the expression and angiogenic properties of AECs’ stemness markers (OCT-4, NANOG, SOX-2) by analysing VEGF expression, angiogenic chemokines’ profiles, and AEC-derived conditioned media activity through an in vitro angiogenic xeno-assay. Results demonstrated that AECs are sensitive to the cytotoxicity effects of CoCl₂. The unique concentration leading to HIF-1α stabilization and nuclear translocation was 10 µM, preserving cell viability and proliferation up to 48 h. CoCl₂ exposure did not modulate stemness markers in AECs while progressively decreasing VEGF expression. On the contrary, CoCl₂ treatment promoted a significant short-term release of angiogenic chemokines in culture media (CM). The enrichment in bio-active factors was confirmed by the ability of CoCl₂-derived CM to induce HUVEC growth and the cells’ organization in tubule-like structures. These findings demonstrate that an appropriate dose of CoCl₂ can be adopted as a hypoxia-mimetic agent in AECs. The short-term, chemical-induced hypoxic condition can be targeted to enhance AECs’ pro-angiogenic properties by providing a novel approach for stem cell-free therapy protocols.

Mesenchymal Stem/Stromal Cells Derived from Human and Animal Perinatal Tissues-Origins, Characteristics, Signaling Pathways, and Clinical Trials

Mesenchymal stem/stromal cells (MSCs) are currently one of the most extensively researched fields due to their promising opportunity for use in regenerative medicine. There are many sources of MSCs, of which cells of perinatal origin appear to be an invaluable pool. Compared to embryonic stem cells, they are devoid of ethical conflicts because they are derived from tissues surrounding the fetus and can be safely recovered from medical waste after delivery. Additionally, perinatal MSCs exhibit better self-renewal and differentiation properties than those derived from adult tissues. It is important to consider the anatomy of perinatal tissues and the general description of MSCs, including their isolation, differentiation, and characterization of different types of perinatal MSCs from both animals and humans (placenta, umbilical cord, amniotic fluid). Ultimately, signaling pathways are essential to consider regarding the clinical applications of MSCs. It is important to consider the origin of these cells, referring to the anatomical structure of the organs of origin, when describing the general and specific characteristics of the different types of MSCs as well as the pathways involved in differentiation.

Differences in the biological properties of mesenchymal stromal cells from traumatic temporomandibular joint fibrous and bony ankylosis: a comparative study

The aim of this study was to compare the functional characteristics of mesenchymal stromal cells (MSCs) from a sheep model of traumatic temporomandibular joint (TMJ) fibrous and bony ankylosis. A sheep model of bilateral TMJ trauma-induced fibrous ankylosis on one side and bony ankylosis on the contralateral side was used. MSCs from fibrous ankylosed callus (FA-MSCs) or bony ankylosed callus (BA-MSCs) at weeks 1, 2, 4, and 8 after surgery were isolated and cultured. MSCs derived from the bone marrow of the mandibular condyle (BM-MSCs) were used as controls. The MSCs from the different sources were characterized morphologically, phenotypically, and functionally. Adherence and trilineage differentiation potential were presented in the ovine MSCs. These cell populations highly positively expressed MSC-associated specific markers, namely CD29, CD44, and CD166, but lacked CD31 and CD45 expressions. The BA-MSCs had higher clonogenic and proliferative potentials than the FA-MSCs. The BA-MSCs also showed higher osteogenic and chondrogenic potentials, but lower adipogenic capacity than the FA-MSCs. In addition, the BA-MSCs demonstrated higher chondrogenic, but lower osteogenic capacity than the BM-MSCs. Our study suggests that inhibition of the osteogenic and chondrogenic differentiations of MSCs might be a promising strategy for preventing bony ankylosis in the future.

In Vitro Innovation of Tendon Tissue Engineering Strategies

Tendinopathy is the term used to refer to tendon disorders. Spontaneous adult tendon healing results in scar tissue formation and fibrosis with suboptimal biomechanical properties, often resulting in poor and painful mobility. The biomechanical properties of the tissue are negatively affected. Adult tendons have a limited natural healing capacity, and often respond poorly to current treatments that frequently are focused on exercise, drug delivery, and surgical procedures. Therefore, it is of great importance to identify key molecular and cellular processes involved in the progression of tendinopathies to develop effective therapeutic strategies and drive the tissue toward regeneration. To treat tendon diseases and support tendon regeneration, cell-based therapy as well as tissue engineering approaches are considered options, though none can yet be considered conclusive in their reproduction of a safe and successful long-term solution for full microarchitecture and biomechanical tissue recovery. In vitro differentiation techniques are not yet fully validated. This review aims to compare different available tendon in vitro differentiation strategies to clarify the state of art regarding the differentiation process.

Tendon and Ligament Healing and Current Approaches to Tendon and Ligament Regeneration

Ligament and tendon injuries are common problems in orthopedics. There is a need for treatments that can expedite nonoperative healing or improve the efficacy of surgical repair or reconstruction of ligaments and tendons. Successful biologically-based attempts at repair and reconstruction would require a thorough understanding of normal tendon and ligament healing. The inflammatory, proliferative, and remodeling phases, and the cells involved in tendon and ligament healing will be reviewed. Then, current research efforts focusing on biologically-based treatments of ligament and tendon injuries will be summarized, with a focus on stem cells endogenous to tendons and ligaments. Statement of clinical significance: This paper details mechanisms of ligament and tendon healing, as well as attempts to apply stem cells to ligament and tendon healing. Understanding of these topics could lead to more efficacious therapies to treat ligament and tendon injuries. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:7-12, 2020.

In Vitro Effect of Estradiol and Progesterone on Ovine Amniotic Epithelial Cells

Amniotic epithelial cells (AECs), an emerging source of extrafoetal stem cells, have recently attracted attention for their great regenerative potential. Since AEC amplifications are accompanied by the loss of their native epithelial phenotype and by the progressive reduction of relevant biological properties, the issue to be addressed is the development of effective culture protocols. In this context, recently, it has been demonstrated that progesterone (P₄) supplementation during ovine AEC (oAEC) expansion could prevent the undesirable epithelial-mesenchymal transition (EMT). In contrast, there is no information to date on the role of the other pregnancy steroids in culture. With this aim, the present study has been designed to clarify the impact of estradiol (E₂), alone or in combination with P₄ (12.5 μM and 25 μM), during oAEC amplification. Steroid supplementations were assessed by testing oAEC proliferation, stemness, EMT, and osteogenic or chondrogenic plasticity. The results indicated that EMT can be prevented exclusively in the presence of high doses of P₄, while it occurred rapidly in cells exposed to E₂ as denoted by protein (cytokeratin-8 and alpha-SMA) and gene expression (vimentin and snail) profiles. Moreover, steroid exposure was able to influence highly oAEC plasticity. Particularly, P₄-treated cells displayed a precommitment towards osteogenic lineage, confirmed by the upregulation of OCN, RUNX2, and the greater deposition of calcium nodules. Conversely, P₄ exposure inhibited oAEC chondrogenic differentiation, which was induced in E₂-treated cells as confirmed by the upregulation of chondrogenesis-related genes (SOX9, ACAN, and COL2A1) and by the accumulation of Alcian blue-positive extracellular matrix. Simultaneously, E₂-treated cells remained unresponsive to osteogenic inductive stimuli. In conclusion, media supplementation with high doses of steroids may be adopted to modulate phenotype and plasticity during oAEC amplification. Relevantly, the osteo or chondro steroid-induced precommitment may open unprecedented cell-based therapies to face the unsolved orthopaedic issues related to osteochondral regeneration.

Placental Stem Cells from Domestic Animals: Translational Potential and Clinical Relevance

The field of regenerative medicine is moving toward clinical practice in veterinary science. In this context, placenta-derived stem cells isolated from domestic animals have covered a dual role, acting both as therapies for patients and as a valuable cell source for translational models. The biological properties of placenta-derived cells, comparable among mammals, make them attractive candidates for therapeutic approaches. In particular, stemness features, low immunogenicity, immunomodulatory activity, multilineage plasticity, and their successful capacity for long-term engraftment in different host tissues after autotransplantation, allo-transplantation, or xenotransplantation have been demonstrated. Their beneficial regenerative effects in domestic animals have been proven using preclinical studies as well as clinical trials starting to define the mechanisms involved. This is, in particular, for amniotic-derived cells that have been thoroughly studied to date. The regenerative role arises from a mutual tissue-specific cell differentiation and from the paracrine secretion of bioactive molecules that ultimately drive crucial repair processes in host tissues (e.g., anti-inflammatory, antifibrotic, angiogenic, and neurogenic factors). The knowledge acquired so far on the mechanisms of placenta-derived stem cells in animal models represent the proof of concept of their successful use in some therapeutic treatments such as for musculoskeletal disorders. In the next future, legislation in veterinary regenerative medicine will be a key element in order to certify those placenta-derived cell-based protocols that have already demonstrated their safety and efficacy using rigorous approaches and to improve the degree of standardization of cell-based treatments among veterinary clinicians.

Mesenchymal stem cells for tendon healing: what is on the horizon?

Tendon injuries are a noteworthy morbidity but at present there are few effective scientifically proven treatments. In recent decades, a number of new strategies including tissue engineering with mesenchymal stem cells (MSCs) have been proposed to enhance tendon healing. Although MSCs are an interesting and promising approach, many questions regarding their use in tendon repair remain unanswered. This descriptive overview of the literature of the last decade explores the in vivo studies on tendon healing, in small and large animal models, which used MSCs harvested from different tissues, and the state of the art in clinical applications. It was observed that there are still doubts about the optimum amount of MSCs to use and their source and the type of scaffolds to deliver the cells. Thus, further studies are needed to determine the best protocol for MSC use in tendon healing. Copyright © 2016 John Wiley & Sons, Ltd.

Tracking of autologous adipose tissue-derived mesenchymal stromal cells with in vivo magnetic resonance imaging and histology after intralesional treatment of artificial equine tendon lesions--a pilot study

BACKGROUND

Adipose tissue-derived mesenchymal stromal cells (AT-MSCs) are frequently used to treat equine tendinopathies. Up to now, knowledge about the fate of autologous AT-MSCs after intralesional injection into equine superficial digital flexor tendons (SDFTs) is very limited. The purpose of this study was to monitor the presence of intralesionally injected autologous AT-MSCs labelled with superparamagnetic iron oxide (SPIO) nanoparticles and green fluorescent protein (GFP) over a staggered period of 3 to 9 weeks with standing magnetic resonance imaging (MRI) and histology.

METHODS

Four adult warmblood horses received a unilateral injection of 10 × 10(6) autologous AT-MSCs into surgically created front-limb SDFT lesions. Administered AT-MSCs expressed lentivirally transduced reporter genes for GFP and were co-labelled with SPIO particles in three horses. The presence of AT-MSCs in SDFTs was evaluated by repeated examinations with standing low-field MRI in two horses and post-mortem in all horses with Prussian blue staining, fluorescence microscopy and with immunofluorescence and immunohistochemistry using anti-GFP antibodies at 3, 5, 7 and 9 weeks after treatment.

RESULTS

AT-MSCs labelled with SPIO particles were detectable in treated SDFTs during each MRI in T2*- and T1-weighted sequences until the end of the observation period. Post-mortem examinations revealed that all treated tendons contained high numbers of SPIO- and GFP-labelled cells.

CONCLUSIONS

Standing low-field MRI has the potential to track SPIO-labelled AT-MSCs successfully. Histology, fluorescence microscopy, immunofluorescence and immunohistochemistry are efficient tools to detect labelled AT-MSCs after intralesional injection into surgically created equine SDFT lesions. Intralesional injection of 10 × 10(6) AT-MSCs leads to the presence of high numbers of AT-MSCs in and around surgically created tendon lesions for up to 9 weeks. Integration of injected AT-MSCs into healing tendon tissue is an essential pathway after intralesional administration. Injection techniques have to be chosen deliberately to avoid reflux of the cell substrate injected. In vivo low-field MRI may be used as a non-invasive tool to monitor homing and engraftment of AT-MSCs in horses with tendinopathy of the SDFT.

M1 and M2 macrophage recruitment during tendon regeneration induced by amniotic epithelial cell allotransplantation in ovine

Recently, we have demonstrated that ovine amniotic epithelial cells (oAECs) allotransplanted into experimentally induced tendon lesions are able to stimulate tissue regeneration also by reducing leukocyte infiltration. Amongst leukocytes, macrophages (Mφ) M1 and M2 phenotype cells are known to mediate inflammatory and repairing processes, respectively. In this research it was investigated if, during tendon regeneration induced by AECs allotransplantation, M1Mφ and M2Mφ phenotype cells are recruited and differently distributed within the lesion site. Ovine AECs treated and untreated (Ctr) tendons were explanted at 7, 14, and 28 days and tissue microarchitecture was analyzed together with the distribution and quantification of leukocytes (CD45 positive), Mφ (CD68 pan positive), and M1Mφ (CD86, and IL12b) and M2Mφ (CD206, YM1 and IL10) phenotype related markers. In oAEC transplanted tendons CD45 and CD68 positive cells were always reduced in the lesion site. At day 14, oAEC treated tendons began to recover their microarchitecture, contextually a reduction of M1Mφ markers, mainly distributed close to oAECs, and an increase of M2Mφ markers was evidenced. CD206 positive cells were distributed near the regenerating areas. At day 28 oAECs treated tendons acquired a healthy-like structure with a reduction of M2Mφ. Differently, Ctr tendons maintained a disorganized morphology throughout the experimental time and constantly showed high values of M1Mφ markers. These findings indicate that M2Mφ recruitment could be correlated to tendon regeneration induced by oAECs allotransplantation. Moreover, these results demonstrate oAECs immunomodulatory role also in vivo and support novel insights into their allogeneic use underlying the resolution of tendon fibrosis.

Stem cell technology for tendon regeneration: current status, challenges, and future research directions

Tendon injuries are a common cause of physical disability. They present a clinical challenge to orthopedic surgeons because injured tendons respond poorly to current treatments without tissue regeneration and the time required for rehabilitation is long. New treatment options are required. Stem cell-based therapies offer great potential to promote tendon regeneration due to their high proliferative, synthetic, and immunomodulatory activities as well as their potential to differentiate to the target cell types and undergo genetic modification. In this review, I first recapped the challenges of tendon repair by reviewing the anatomy of tendon. Next, I discussed the advantages and limitations of using different types of stem cells compared to terminally differentiated cells for tendon tissue engineering. The safety and efficacy of application of stem cells and their modified counterparts for tendon tissue engineering were then summarized after a systematic literature search in PubMed. The challenges and future research directions to enhance, optimize, and standardize stem cell-based therapies for augmenting tendon repair were then discussed.

Isolation and morphological characterization of ovine amniotic fluid mesenchymal stem cells

Mesenchymal stem cells (MSCs) are one of the most promising cell populations for tissue engineering and regenerative medicine. Of utmost importance to MSC research is identification of MSC sources that are easily obtainable and stable. Several studies have shown that MSCs can be isolated from amniotic fluid. The sheep is one of the main types of farm animal, and it has many biophysical and biochemical similarities to humans. Here, we obtained MSCs from ovine amniotic fluid and determined the expansion capacity, surface and intracellular marker expression, karyotype, and multilineage differentiation ability of these ovine amniotic fluid mesenchymal stem cells (oAF-MSCs). Moreover, expression levels of differentiation markers were measured using reverse transcription-qPCR (RT-qPCR). Our phenotypic analysis shows that the isolated oAF-MSCs are indeed MSCs.

Gestational stage affects amniotic epithelial cells phenotype, methylation status, immunomodulatory and stemness properties

Stem cells isolated from amniotic epithelium (AECs) have shown great potential in cell-based regenerative therapies. Because of their fetal origin, these cells exhibit elevated proliferation rates and plasticity, as well as, immune tolerance and anti-inflammatory properties. These inherent attitudes make AECs well-suited for both allogenic and xenogenic cellular transplants in animal models. Since in human only at term amnion is easily obtainable after childbirth, limited information are so far available concerning the phenotypic and functional difference between AECs isolated from early and late amnia. To this regard, the sheep animal model offers an undoubted advantage in allowing the easy collection of both types of AECs in large quantity. The aim of this study was to determine the effect of gestational age on ovine AECs (oAECs) phenotype, immunomodulatory properties, global DNA methylation status and pluripotent differentiation ability towards mesodermic and ectodermic lineages. The immunomodulatory property of oAECs in inhibiting lymphocyte proliferation was mainly unaffected by gestational age. Conversely, gestation considerably affected the expression of surface markers, as well the expression and localization of pluripotency markers. In detail, with progression of gestation the mRNA expression of NANOG and SOX2 markers was reduced, while the ones of TERT and OCT4A was unaltered; but at the end of gestation NANOG, SOX2 and TERT proteins mainly localized outside the nuclear compartment. Regarding the differentiation ability, LPL (adipogenic-specific gene) mRNA content significantly increased in oAECs isolated from early amnia, while OCN (osteogenic-specific gene) and NEFM (neurogenic-specific gene) mRNA content significantly increased in oAECs isolated from late amnia, suggesting that gestational stage affected cell plasticity. Finally, the degree of global DNA methylation increased with gestational age. All these results indicate that gestational age is a key factor capable of influencing morphological and functional properties of oAECs, and thus probably affecting the outcome of cell transplantation therapies.

Stem cells from foetal adnexa and fluid in domestic animals: an update on their features and clinical application

Over the past decade, stem cell research has emerged as an area of major interest for its potential in regenerative medicine applications. This is in constant need of new cell sources to conceive regenerative medicine approaches for diseases that are still without therapy. Scientists drew the attention towards alternative sources such as foetal adnexa and fluid, as these sources possess many advantages: first of all, cells can be extracted from discarded foetal material and it is non-invasive and inexpensive for the patient; secondly, abundant stem cells can be obtained; and finally, these stem cell sources are free from ethical considerations. Cells derived from foetal adnexa and fluid preserve some of the characteristics of the primitive embryonic layers from which they originate. Many studies have demonstrated the differentiation potential in vitro and in vivo towards mesenchymal and non-mesenchymal cell types; in addition, the immune-modulatory properties make these cells a good candidate for allo- and xenotransplantation. Naturally occurring diseases in domestic animals can be more ideal as disease model of human genetic and acquired diseases and could help to define the potential therapeutic use efficiency and safety of stem cells therapies. This review offers an update on the state of the art of characterization of domestic animals' MSCs derived from foetal adnexa and fluid and on the latest findings in pre-clinical or clinical setting of the stem cell populations isolated from these sources.

Calcium sensing receptor expression in ovine amniotic fluid mesenchymal stem cells and the potential role of R-568 during osteogenic differentiation

Amniotic fluid-derived stem (AFS) cells have been identified as a promising source for cell therapy applications in bone traumatic and degenerative damage. Calcium Sensing Receptor (CaSR), a G protein-coupled receptor able to bind calcium ions, plays a physiological role in regulating bone metabolism. It is expressed in different kinds of cells, as well as in some stem cells. The bone CaSR could potentially be targeted by allosteric modulators, in particular by agonists such as calcimimetic R-568, which may potentially be helpful for the treatment of bone disease. The aim of our study was first to investigate the presence of CaSR in ovine Amniotic Fluid Mesenchymal Stem Cells (oAFMSCs) and then the potential role of calcimimetics in in vitro osteogenesis. oAFMSCs were isolated, characterized and analyzed to examine the possible presence of CaSR by western blotting and flow cytometry analysis. Once we had demonstrated CaSR expression, we worked out that 1 µM R-568 was the optimal and effective concentration by cell viability test (MTT), cell number, Alkaline Phosphatase (ALP) and Alizarin Red S (ARS) assays. Interestingly, we observed that basal diffuse CaSR expression in oAFMSCs increased at the membrane when cells were treated with R-568 (1 µM), potentially resulting in activation of the receptor. This was associated with significantly increased cell mineralization (ALP and ARS staining) and augmented intracellular calcium and Inositol trisphosphate (IP3) levels, thus demonstrating a potential role for calcimimetics during osteogenic differentiation. Calhex-231, a CaSR allosteric inhibitor, totally reversed R-568 induced mineralization. Taken together, our results demonstrate for the first time that CaSR is expressed in oAFMSCs and that calcimimetic R-568, possibly through CaSR activation, can significantly improve the osteogenic process. Hence, our study may provide useful information on the mechanisms regulating osteogenesis in oAFMSCs, perhaps prompting the use of calcimimetics in bone regenerative medicine.

In vitro fabrication of autologous living tissue-engineered vascular grafts based on prenatally harvested ovine amniotic fluid-derived stem cells

Amniotic fluid cells (AFCs) have been proposed as a valuable source for tissue engineering and regenerative medicine. However, before clinical implementation, rigorous evaluation of this cell source in clinically relevant animal models accepted by regulatory authorities is indispensable. Today, the ovine model represents one of the most accepted preclinical animal models, in particular for cardiovascular applications. Here, we investigate the isolation and use of autologous ovine AFCs as cell source for cardiovascular tissue engineering applications. Fetal fluids were aspirated in vivo from pregnant ewes (n = 9) and from explanted uteri post mortem at different gestational ages (n = 91). Amniotic non-allantoic fluid nature was evaluated biochemically and in vivo samples were compared with post mortem reference samples. Isolated cells revealed an immunohistochemical phenotype similar to ovine bone marrow-derived mesenchymal stem cells (MSCs) and showed expression of stem cell factors described for embryonic stem cells, such as NANOG and STAT-3. Isolated ovine amniotic fluid-derived MSCs were screened for numeric chromosomal aberrations and successfully differentiated into several mesodermal phenotypes. Myofibroblastic ovine AFC lineages were then successfully used for the in vitro fabrication of small- and large-diameter tissue-engineered vascular grafts (n = 10) and cardiovascular patches (n = 34), laying the foundation for the use of this relevant pre-clinical in vivo assessment model for future amniotic fluid cell-based therapeutic applications.

Synthetic bone substitute engineered with amniotic epithelial cells enhances bone regeneration after maxillary sinus augmentation

Background

Evidence has been provided that a cell-based therapy combined with the use of bioactive materials may significantly improve bone regeneration prior to dental implant, although the identification of an ideal source of progenitor/stem cells remains to be determined.

Aim

In the present research, the bone regenerative property of an emerging source of progenitor cells, the amniotic epithelial cells (AEC), loaded on a calcium-phosphate synthetic bone substitute, made by direct rapid prototyping (rPT) technique, was evaluated in an animal study.

Material And Methods

Two blocks of synthetic bone substitute (∼0.14 cm³), alone or engineered with 1×10⁶ ovine AEC (oAEC), were grafted bilaterally into maxillary sinuses of six adult sheep, an animal model chosen for its high translational value in dentistry. The sheep were then randomly divided into two groups and sacrificed at 45 and 90 days post implantation (p.i.). Tissue regeneration was evaluated in the sinus explants by micro-computer tomography (micro-CT), morphological, morphometric and biochemical analyses.

Results And Conclusions

The obtained data suggest that scaffold integration and bone deposition are positively influenced by allotransplantated oAEC. Sinus explants derived from sheep grafted with oAEC engineered scaffolds displayed a reduced fibrotic reaction, a limited inflammatory response and an accelerated process of angiogenesis. In addition, the presence of oAEC significantly stimulated osteogenesis either by enhancing bone deposition or making more extent the foci of bone nucleation. Besides the modulatory role played by oAEC in the crucial events successfully guiding tissue regeneration (angiogenesis, vascular endothelial growth factor expression and inflammation), data provided herein show that oAEC were also able to directly participate in the process of bone deposition, as suggested by the presence of oAEC entrapped within the newly deposited osteoid matrix and by their ability to switch-on the expression of a specific bone-related protein (osteocalcin, OCN) when transplanted into host tissues.

Role of amniotic fluid mesenchymal cells engineered on MgHA/collagen-based scaffold allotransplanted on an experimental animal study of sinus augmentation

OBJECTIVES

The present research has been performed to evaluate whether a commercial magnesium-enriched hydroxyapatite (MgHA)/collagen-based scaffold engineered with ovine amniotic fluid mesenchymal cells (oAFMC) could improve bone regeneration process in vivo.

MATERIALS AND METHODS

Bilateral sinus augmentation was performed on eight adult sheep in order to compare the tissue regeneration process at 45 and 90 days after implantation of the oAFMC-engineered scaffold (Test Group) or of the scaffold alone (Ctr Group). The process of tissue remodeling was analyzed through histological, immunohistochemical, and morphometric analyses by calculating the proliferation index (PI) of oAFMC loaded on the scaffold, the total vascular area (VA), and vascular endothelial growth factor (VEGF) expression levels within the grafted area.

RESULTS

MgHA/collagen-based scaffold showed high biocompatibility preserving the survival of oAFMC for 90 days in grafted sinuses. The use of oAFMC increased bone deposition and stimulated a more rapid angiogenic reaction, thus probably supporting the higher cell PI recorded in cell-treated sinuses. A significantly higher VEGF expression (Test vs. Ctr Group; p = 0.0004) and a larger total VA (p = 0.0006) were detected in the Test Group at 45 days after surgery. The PI was significantly higher (p = 0.027) at 45 days and became significantly lower at 90 days (p = 0.0007) in the Test Group sinuses, while the PI recorded in the Ctr Group continued to increase resulting to a significantly higher PI at day 90 (CTR day 45 vs. CTR day 90; p = 0.022).

CONCLUSIONS

The osteoinductive effect of a biomimetic commercial scaffold may be significantly improved by the presence of oAFMC.

CLINICAL RELEVANCE

The amniotic fluid mesenchymal cell (AFMC) may represent a novel, largely and easily accessible source of mesenchymal stem cells to develop cell-based therapy for maxillofacial surgery.