Periosteum-derived cells as an alternative to bone marrow cells for bone tissue engineering around dental implants. A histomorphometric study in beagle dogs

Regulatory effects of stress release from decellularized periosteum on proliferation, migration, and osteogenic differentiation of periosteum-derived cells

Bone injury is often associated with tears in the periosteum and changes in the internal stress microenvironment of the periosteum. In this study, we investigated the biological effects of periosteal prestress release on periosteum-derived cells (PDCs) and the potential mechanisms of endogenous stem cell recruitment. Decellularized periosteum with natural extracellular matrix (ECM) components was obtained by a combination of physical, chemical, and enzymatic decellularization. The decellularized periosteum removed immunogenicity while retaining the natural network structure and composition of the ECM. The Young's modulus has no significant difference between the periosteum before and after decellularization. The extracted PDCs were further composited with the decellularized periosteum and subjected to 20% stress release. It was found that the proliferative capacity of PDCs seeded on decellularized periosteum was significantly enhanced 6 h after stress release of the periosteum. The cell culture supernatant obtained after periosteal prestress release was able to significantly promote the migration ability of PDCs within 24 h. Enzyme-linked immunosorbnent assay (ELISA) experiments showed that the expression of stroma-derived factor-1α (SDF-1α) and vascular endothelial growth factor (VEGF) in the supernatant increased significantly after 3 h and 12 h of stress release, respectively. Furthermore, periosteal stress release promoted the high expression of osteogenic markers osteocalcin (OCN), osteopontin (OPN), and collagen type I of PDCs. The change in stress environment caused by the release of periosteal prestress was sensed by integrin β1, a mechanoreceptor on the membrane of PDCs, which further stimulated the expression of YAP in the nucleus. These investigations provided a novel method to evaluate the importance of mechanical stimulation in periosteum, which is also of great significance for the design and fabrication of artificial periosteum with mechanical regulation function.

Potential of periosteal cells in bone and cartilage regeneration: a systematic review

Introduction: The unavailability of adequate human primary cells presents multiple challenges in terms of bone and cartilage regeneration and disease modeling experiments in vitro. Periosteal cells (PCs), which represent promising skeletal stem cell sources, could be a promising strategy in tissue engineering. The present study aimed to summarize the characteristics of PCs to investigate the efficacy of these cells in bone and cartilage regeneration in different models, paying special attention to the comparison of bone marrow stromal cells (BMSCs). Methods: A comprehensive literature search was conducted in Embase, PubMed/MEDLINE, Web of Science, and Scopus for articles published in English until April 2023. Only original researches in which PCs were employed for bone or cartilage regeneration experiments were included. Results: A total of 9140 references were retrieved. After screening the results, 36 publications were considered to be eligible for inclusion in the present literature review. Overall, PCs demonstrated beneficial bone and cartilage regenerative efficacy compared to the bare scaffold since almost all included studies reported positive results. The 9 studies assessing the differences in bone formation capacity between PCs and BMSCs indicated that PCs exhibited stronger in vivo osteogenic differentiation capabilities compared to BMSCs, while the other study demonstrated stronger chondrogenic potential of BMSCs. Discussion: PCs demonstrated beneficial to bone regenerative efficacy compared to the bare scaffold with a low risk of most studies included. However, the cartilage formation capacity of BMSCs still needs to be investigated due to the limited research available and the certain risk of bias. PCs exhibited higher osteogenic capabilities compared to BMSCs in combination with various scaffolds in vivo with good evidence. Further researches are needed to elucidate the comparative benefits of cartilage regeneration. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023411522, CRD42023411522.

From Free Tissue Transfer to Hydrogels: A Brief Review of the Application of the Periosteum in Bone Regeneration

The periosteum is a thin layer of connective tissue covering bone. It is an essential component for bone development and fracture healing. There has been considerable research exploring the application of the periosteum in bone regeneration since the 19th century. An increasing number of studies are focusing on periosteal progenitor cells found within the periosteum and the use of hydrogels as scaffold materials for periosteum engineering and guided bone development. Here, we provide an overview of the research investigating the use of the periosteum for bone repair, with consideration given to the anatomy and function of the periosteum, the importance of the cambium layer, the culture of periosteal progenitor cells, periosteum-induced ossification, periosteal perfusion, periosteum engineering, scaffold vascularization, and hydrogel-based synthetic periostea.

Characterization and potential of periosteum-derived cells: an overview

As a thin fibrous layer covering the bone surface, the periosteum plays a significant role in bone physiology during growth, development and remodeling. Over the past several decades, the periosteum has received considerable scientific attention as a source of mesenchymal stem cells (MSCs). Periosteum-derived cells (PDCs) have emerged as a promising strategy for tissue engineering due to their chondrogenic, osteogenic and adipogenic differentiation capacities. Starting from the history of PDCs, the present review provides an overview of their characterization and the procedures used for their isolation. This study also summarizes the chondrogenic, osteogenic, and adipogenic abilities of PDCs, serving as a reference about their potential therapeutic applications in various clinical scenarios, with particular emphasis on the comparison with other common sources of MSCs. As techniques continue to develop, a comprehensive analysis of the characterization and regulation of PDCs can be conducted, further demonstrating their role in tissue engineering. PDCs present promising potentials in terms of their osteogenic, chondrogenic, and adipogenic capacities. Further studies should focus on exploring their utility under multiple clinical scenarios to confirm their comparative benefit over other commonly used sources of MSCs.

A systematic review of bone marrow stromal cells and periosteum-derived cells for bone regeneration

Bone marrow stromal cells (BMSCs) and periosteum-derived cells (PDCs) represent promising skeletal stem cell sources to treat critical-size bone defects. However, the large number of preclinical tests with a variety of in vivo data complicates the selection of cells for further clinical translation. This systematic review aims to analyze the in vivo bone-forming efficacy of BMSCs- and PDCs-based approaches in all published preclinical experiments until November 2020. For this purpose, four databases (PubMed, Embase, Cochrane Central Register of Controlled Trial, and Web of Science) were searched for eligible literature, which yielded a total of 94 full-text articles for systematic review. This review generated an evidence-based list of BMSC- or PDC-based approaches, which have been evaluated for bone formation in different animal models. Among them, 74 studies were included for pairwise and network meta-analysis. The results revealed that both PDC and BMSC had beneficial bone-forming efficacy compared to bare scaffold. In addition, BMSC- and PDC-based approaches had no significant difference regarding in vivo bone-forming efficacy. However, BMSC-based approach had a higher probability to be ranked better than PDC-based approach. Furthermore, the review discusses (i) the possible risk of bias of the in vivo evaluation of cell-based approaches, (ii) the difficulty in replication of such experiments due to frequent poor reporting of the methods and results, and (iii) the clinical relevance of the currently utilized BMSC- and PDC-based approaches. Systematic review registration: The study was prospectively registered in PROSPERO, Registration No. CRD42021270922.

Isolation of Mesenchymal Stem Cells from Human Alveolar Periosteum and Effects of Vitamin D on Osteogenic Activity of Periosteum-derived Cells

Mesenchymal stem cells (MSCs) are present in a variety of tissues and can be differentiated into numerous cell types, including osteoblasts. Among the dental sources of MSCs, the periosteum is an easily accessible tissue, which has been identified to contain MSCs in the cambium layer. However, this source has not yet been widely studied. Vitamin D3 and 1,25-(OH)2D3 have been demonstrated to stimulate in vitro differentiation of MSCs into osteoblasts. In addition, vitamin C facilitates collagen formation and bone cell growth. However, no study has yet investigated the effects of Vitamin D3 and Vitamin C on MSCs. Here, we present a method of isolating MSCs from human alveolar periosteum and examine the hypothesis that 1,25-(OH)2D3 may exert an osteoinductive effect on these cells. We also investigate the presence of MSCs in the human alveolar periosteum and assess stem cell adhesion and proliferation. To assess the ability of vitamin C (as a control) and various concentrations of 1,25-(OH)2D3 (10^-10, 10^-9, 10^-8, and 10^-7 M) to alter key mRNA biomarkers in isolated MSCs mRNA expression of alkaline phosphatase (ALP), bone sialoprotein (BSP), core binding factor alpha-1 (CBFA1), collagen-1, and osteocalcin (OCN) are measured using real-time polymerase chain reaction (RT-PCR).

Bone tissue engineering in oral peri-implant defects in preclinical in vivo research: A systematic review and meta-analysis

The regeneration and establishment of osseointegration within oral peri-implant bone defects remains a clinical challenge. Bone tissue engineering (BTE) is emerging as a promising alternative to autogenous and/or biomaterial-based bone grafting. The objective of this systematic review was to answer the focused question: in animal models, do cell-based BTE strategies enhance bone regeneration and/or implant osseointegration in experimental peri-implant defects, compared with grafting with autogenous bone or only biomaterial scaffolds? Electronic databases were searched for controlled animal studies reporting on peri-implant defects and implantation of mesenchymal stem cells (MSC) or other cells seeded on biomaterial scaffolds, following Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Random effects meta-analyses were performed for the outcomes histomorphometric bone area fraction (BA) and bone-to-implant contact (BIC). Nineteen studies reporting on large animal models (dogs and sheep) were included. Experimental defects were created surgically (16 studies) or via ligature-induced peri-implantitis (LIPI, three studies). In general, studies presented with an unclear to high risk of bias. In most studies, MSC were used in combination with alloplastic mineral phase or polymer scaffolds; no study directly compared cell-loaded scaffolds vs. autogenous bone. In three studies, cells were also modified by ex vivo gene transfer of osteoinductive factors. The meta-analyses indicated statistically significant benefits in favour of: (a) cell-loaded vs. cell-free scaffolds [weighted mean differences (WMD) of 10.73-12.30% BA and 11.77-15.15% BIC] in canine surgical defect and LIPI models; and (b) gene-modified vs. unmodified cells (WMD of 29.44% BA and 16.50% BIC) in canine LIPI models. Overall, heterogeneity in the meta-analyses was high (I² 70-88%); considerable variation was observed among studies regarding the nature of cells and scaffolds used. In summary, bone regeneration and osseointegration in peri-implant defects are enhanced by the addition of osteogenic cells to biomaterial scaffolds. Although the direction of treatment outcome is clearly in favour of BTE strategies, due to the limited magnitude of treatment effect observed, no conclusive statements regarding the clinical benefit of such procedures for oral indications can yet be made. Copyright © 2017 John Wiley & Sons, Ltd.

Live Tissue Imaging to Elucidate Mechanical Modulation of Stem Cell Niche Quiescence

The periosteum, a composite cellular connective tissue, bounds all nonarticular bone surfaces. Like Velcro, collagenous Sharpey's fibers anchor the periosteum in a prestressed state to the underlying bone. The periosteum provides a niche for mesenchymal stem cells. Periosteal lifting, as well as injury, causes cells residing in the periosteum (PDCs) to change from an immobile, quiescent state to a mobile, active state. The physical cues that activate PDCs to home to and heal injured areas remain a conundrum. An understanding of these cues is key to unlocking periosteum's remarkable regenerative power. We hypothesized that changes in periosteum's baseline stress state modulate the quiescence of its stem cell niche. We report, for the first time, a three-dimensional, high-resolution live tissue imaging protocol to observe and characterize ovine PDCs and their niche before and after release of the tissue's endogenous prestress. Loss of prestress results in abrupt shrinkage of the periosteal tissue. At the microscopic scale, loss of prestress results in significantly increased crimping of collagen of periosteum's fibrous layer and a threefold increase in the number of rounded nuclei in the cambium layer. Given the body of published data describing the relationships between stem cell and nucleus shape, structure and function, these observations are consistent with a role for mechanics in the modulation of periosteal niche quiescence. The quantitative characterization of periosteum as a stem cell niche represents a critical step for clinical translation of the periosteum and periosteum substitute-based implants for tissue defect healing. Stem Cells Translational Medicine 2017;6:285-292.

Efficacy of stem cells on the healing of peri-implant defects: systematic review of preclinical studies

This systematic review considers the evidence from animal studies evaluating the effectiveness of mesenchymal stem cells (MSC) in the treatment of intraoral peri-implant defects. MEDLINE, EMBASE, and LILACS databases were searched for quantitative preclinical controlled animal model studies that evaluated the effect of MSC on bone healing at intraoral peri-implant bone defects. The primary outcome was the amount of (re-)osseointegration reported as bone-to-implant contact in the defect area. The systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement guidelines. Ten studies met the inclusion criteria. Only one study induced peri-implant inflammation to produce peri-implant bone defects. In all others, defects were surgically created at implant installation. Differences in defect morphology were identified among the studies. Both xenogenous and autogenous MSC were used to treat peri-implant defects. These included bone marrow-derived MSC, periodontal ligament-derived MSC, umbilical cord MSC, bone marrow-derived mononuclear cells, and peripheral blood mononuclear cells. Meta-analysis was not possible because of heterogeneities in study designs. Nonetheless, in most studies, local MSC implantation was not associated with adverse effects and had a positive effect on bone healing around peri-implant defects. Combination of MSC with membranes and bioactive factors appears to provide improved treatment outcomes. In large animal models, intraoral use of MSC may provide beneficial effects on bone healing within peri-implant defects. The various degrees of success of MSC in peri-implant bone healing are likely to be related to the use of cells from various populations, tissues, and donor species. However, human safety and efficacy must be demonstrated before its clinical use can be considered.

Treatment of Peri-Implant Defects in the Rabbit's Tibia with Adipose or Bone Marrow-Derived Mesenchymal Stems Cells

BACKGROUND

Mesenchymal stem cell (MSC) treatment in conjunction with bone graft materials or space filler can be an alternative to autogenous bone grafts in the treatment of peri-implant bone defects.

PURPOSE

To evaluate the success of bone regeneration capacity of adipose-derived and bone marrow-derived MSCs for the treatment of peri-implant bone defects when applied with a beta-tricalcium phosphate/collagen-based scaffold.

MATERIAL AND METHODS

Forty implants were placed into the tibiae of 10 rabbits bilaterally. Surgical defects created around the implants were treated with one the following treatment modalities: 1) adipose-derived MSC transplanted scaffold + collagen membrane; 2) bone marrow-derived MSC transplanted scaffold + collagen membrane; 3) autogenous bone + collagen membrane; and 4) collagen membrane only. The bone regeneration capacity of each technique was determined by histomorphometry, micro-CT, and measuring the implant stability by resonance frequency analysis.

RESULTS

One limb of one rabbit was excluded because of fracture, and another limb was excluded because of infection. All parameters on 36 implants revealed that both sources of MSC can form equivalently new bone that is comparable with autogenous bone. The defects treated with membrane only had significantly less bone formation compared with other groups.

CONCLUSION

Both adipose-derived and bone marrow-derived MSC treatments are feasible alternatives to autogenous bone grafts in the treatment of peri-implant osseos defects.

Analysis of αSMA-labeled progenitor cell commitment identifies notch signaling as an important pathway in fracture healing

Fracture healing is a regenerative process that involves coordinated responses of many cell types, but characterization of the roles of specific cell populations in this process has been limited. We have identified alpha smooth muscle actin (αSMA) as a marker of a population of mesenchymal progenitor cells in the periosteum that contributes to osteochondral elements during fracture healing. Using a lineage tracing approach, we labeled αSMA-expressing cells, and characterized changes in the periosteal population during the early stages of fracture healing by histology, flow cytometry, and gene expression profiling. In response to fracture, the αSMA-labeled population expanded and began to differentiate toward the osteogenic and chondrogenic lineages. The frequency of mesenchymal progenitor cell markers such as Sca1 and PDGFRα increased after fracture. By 6 days after fracture, genes involved in matrix production and remodeling were elevated. In contrast, genes associated with muscle contraction and Notch signaling were downregulated after fracture. We confirmed that activating Notch signaling in αSMA-labeled cells inhibited differentiation into osteogenic and adipogenic lineages in vitro and ectopic bone formation in vivo. By characterizing changes in a selected αSMA-labeled progenitor cell population during fracture callus formation, we have shown that modulation of Notch signaling may determine osteogenic potential of αSMA-expressing progenitor cells during bone healing.

Application of stem-cell media to explant culture of human periosteum: An optimal approach for preparing osteogenic cell material

As part of our clinical tests on bone regeneration using cultured periosteal sheets, here, we prepared cultured periosteal sheets in two types of stem-cell culture media, STK1 and STK3. Human periosteum was expanded either in 1% human serum–supplemented STK1 for 28 days, in 1% human serum–supplemented STK1 for 14 days followed by 1% human serum–supplemented STK3 for 14 days (1% human serum–supplemented STK1+3), or in 10% fetal bovine serum–supplemented Medium 199 for 28 days (control). Cultured periosteal sheet diameter and DNA content were significantly higher, and the multilayer structure was prominent in 1% human serum–supplemented STK1 and 1% human serum–supplemented STK1+3. The messenger RNA of osteoblastic markers was significantly upregulated in 1% human serum–supplemented STK1+3. Osteopontin-immunopositive staining and mineralization were evident across a wide area of the cultured periosteal sheet in 1% human serum–supplemented STK1+3. Subcutaneous implantation in nude mice following expansion in 1% human serum–supplemented STK1+3 produced the highest cultured periosteal sheet osteogenic activity. Expansion in 1% human serum–supplemented STK1+3 successfully induced cultured periosteal sheet growth while retaining osteogenic potential, and subsequent osteoblastic induction promoted the production of homogeneous cell material.

Systematic review of pre-clinical models assessing implant integration in locally compromised sites and/or systemically compromised animals

OBJECTIVE

The aim was to systematically search the dental literature for pre-clinical models assessing implant integration in locally compromised sites (part 1) and systemically compromised animals (part 2), and to evaluate the quality of reporting of included publications.

METHODS

A Medline search (1966-2011) was performed, complimented by additional hand searching. The quality of reporting of the included publications was evaluated using the 20 items of the ARRIVE (Animals in Research In Vivo Experiments) guidelines.

RESULTS

One-hundred and seventy-six (part 1; mean ARRIVE score = 15.6 ± 2.4) and 104 (part 2; 16.2 ± 1.9) studies met the inclusion criteria. The overall mean score for all included studies amounted to 15.8 ± 2.2. Housing (38.3%), allocation of animals (37.9%), numbers analysed (50%) and adverse events (51.4%) of the ARRIVE guidelines were the least reported. Statistically significant differences in mean ARRIVE scores were found depending on the publication date (p < 0.05), with the highest score of 16.7 ± 1.6 for studies published within the last 2 years.

CONCLUSIONS

A large number of studies met the inclusion criteria. The ARRIVE scores revealed heterogeneity and missing information for selected items in more than 50% of the publications. The quality of reporting shifted towards better-reported pre-clinical trials within recent years.

Critical size defect regeneration using PEG-mediated BMP-2 gene delivery and the use of cell occlusive barrier membranes - the osteopromotive principle revisited

OBJECTIVE

The objective of this study was to investigate if osseous regeneration can be accelerated by involvement of periosteal tissue. Bone defect regeneration could be accelerated by the involvement of periosteal tissue if osteogenic cell signalling is maintained within the defect. It was questioned if local cell-mediated BMP-2 gene delivery makes a cell occlusive membrane dispensable during bone critical size defect regeneration.

METHODS

PEG matrix (degradation time 10 days) and PEG membrane (degradation time 120 days) were used in the pig calvarial model. Cylindrical (1 × 1 cm) critical size defects (CSD) (9 per animal; 20 animals) were filled with: (i) particulated autologous bone, covered with PEG membrane (group 1); (ii) HA/TCP, covered with PEG membrane (group 2); (iii) HA/TCP, mixed with PEG matrix (group 3); and (iv) HA/TCP mixed with BMP-2-transfected osteoblasts and PEG matrix (group 4). BMP-2/4 gene transfer: liposomal in vitro transfection of BMP-2/V5-tag fusion-protein. Quantitative histomorphometry (toluidine blue staining) after 2, 4 and 12 weeks assessed bone formation. Semiquantitative immunohistochemistry estimated the expression of BMP-2, V5-tag, Runx-2 and Sox9.

RESULTS

PEG matrix embedded BMP-2 expressing cells presented higher bone formation (P < 0.05) than HA/TCP + PEG matrix defect filling or PEG membrane covering (HA/TCP filling) after 12 weeks. Highest expression of BMP-2, Runx-2 and lowest expression of fibrous tissue marker Sox9 was seen in the BMP-2 group.

CONCLUSION

PEG matrix embedded BMP-2 expressing cells are capable to maintain osteogenic signalling and to accelerate osseous defect regeneration in absence of a cell occlusive membrane.

Concise review: the periosteum: tapping into a reservoir of clinically useful progenitor cells

Elucidation of the periosteum and its regenerative potential has become a hot topic in orthopedics. Yet few review articles address the unique features of periosteum-derived cells, particularly in light of translational therapies and engineering solutions inspired by the periosteum's remarkable regenerative capacity. This review strives to define periosteum-derived cells in light of cumulative research in the field; in addition, it addresses clinical translation of current insights, hurdles to advancement, and open questions in the field. First, we examine the periosteal niche and its inhabitant cells and the key characteristics of these cells in the context of mesenchymal stem cells and their relevance for clinical translation. We compare periosteum-derived cells with those derived from the marrow niche in in vivo studies, addressing commonalities as well as features unique to periosteum cells that make them potentially ideal candidates for clinical application. Thereafter, we review the differentiation and tissue-building properties of periosteum cells in vitro, evaluating their efficacy in comparison with marrow-derived cells. Finally, we address a new concept of banking periosteum and periosteum-derived cells as a novel alternative to currently available autogenic umbilical blood and perinatal tissue sources of stem cells for today's population of aging adults who were "born too early" to bank their own perinatal tissues. Elucidating similarities and differences inherent to multipotent cells from distinct tissue niches and their differentiation and tissue regeneration capacities will facilitate the use of such cells and their translation to regenerative medicine.

Repair of critical-size defects with autogenous periosteum-derived cells combined with bovine anorganic apatite/collagen: an experimental study in rat calvaria

The aim of this study was to evaluate the bone repair using autogenous periosteum-derived cells (PDC) and bovine anorganic apatite and collagen (HA-COL). PDC from Wistar rats (n=10) were seeded on HA-COL discs and subjected to osteoinduction during 6 days. Critical-size defects in rat calvarias were treated with blood clot (G1), autogenous bone (G2), HA-COL (G3) and HA-COL combined with PDC (G4) (n=40), and then analyzed 1 and 3 months after surgeries. Radiographic analysis exhibited no significant temporal change. G1 and G2 had discrete new marginal bone, but the radiopacity of graft materials in G2, G3 and G4 impaired the detection of osteogenesis. At 3 months, histopathological analysis showed the presence of ossification islets in G1, which was more evident in G2, homogeneous new bone around HA-COL in G3 and heterogeneous new bone around HA-COL in G4 in addition to moderate presence of foreign body cells in G3 and G4. Histomorphometric analysis showed no change in the volume density of xenograft (p>0.05) and bone volume density in G2 was twice greater than in G1 and G4 after 3 months (p<0.05), but similar to G3. The PDC did not increase bone formation in vivo, although the biomaterial alone showed biocompatibility and osteoconduction capacity.