Osteogenic and Chondrogenic Potential of Periosteum-Derived Mesenchymal Stromal Cells: Do They Hold the Key to the Future?

Functional Outcome Analysis of Autologous Stromal Vascular Fraction (SVF) (Sahaj Therapy®) Using Direct Sonication in Osteonecrosis of the Femoral Head (ONFH): A 6-Year Follow-Up Study

Introduction

We investigated the safety, efficacy, functional, and clinical outcomes of intra-osseous implantation of mechanically isolated, autologous stromal vascular fraction (SVF), an Australian patented direct ultrasonication technology (Sahaj Therapy®) in osteonecrosis of the femoral head (ONFH).

Materials and Methods

A total of 32 cases of ONFH were enrolled in the study after confirming with an MRI of the affected hip. All cases were treated with an intra-osseous autologous SVF implantation [4-5 cc with the cellular dosage of 8.0 × 107 cells with a viability of > 85% SVF cells] on the same surgical sitting. All the cases were followed up clinically, functionally, and radiologically at regular intervals. A comparison of mean HOOS scores at different follow-ups was done using Paired 't'-test. A P value of < 0.05 was considered significant.

Results

In our study, male preponderance was seen (53.1%). According to the modified Ficat and Arlet classification, the most common grade of ONFH was grade 2 [right: 25 hips and left: 25 hips]. There was a statistically significant improvement in the mean HOOS score of the right hip (n = 10) and left hip (n = 9) from preoperative time till 72 months (P < 0.05). The follow-up MRI of the affected hips shows improved osteogenesis without any further worsening of the contour of the femoral head. No adverse effects were seen in any of the study participants.

Conclusion

For individuals with ONFH, treated with intra-osseous autologous SVF implantation in the same surgical procedure is an innovative and promising treatment modality. Even after 6 years of follow-up, the study participants with ONFH have shown good clinical and functional outcomes with autologous SVF.

Evaluation of the regenerative capacity of stem cells combined with bone graft material and collagen matrix using a rabbit calvarial defect model

PURPOSE

The purpose of this study was to evaluate the regenerative capacity of stem cells combined with bone graft material and a collagen matrix in rabbit calvarial defect models according to the type and form of the scaffolds, which included type I collagen matrix and synthetic bone.

METHODS

Mesenchymal stem cells (MSCs) were obtained from the periosteum of participants. Four symmetrical 6-mm-diameter circular defects were made in New Zealand white rabbits using a trephine drill. The defects were grafted with (1) group 1: synthetic bone (β-tricalcium phosphate/hydroxyapatite [β-TCP/HA]) and 1×105 MSCs; (2) group 2: collagen matrix and 1×105 MSCs; (3) group 3: β-TCP/HA, collagen matrix covering β-TCP/HA, and 1×105 MSCs; or (4) group 4: β-TCP/HA, chipped collagen matrix mixed with β-TCP/HA, and 1×105 MSCs. Cellular viability and cell migration rates were analyzed.

RESULTS

Uneventful healing was achieved in all areas where the defects were made at 4 weeks, and no signs of infection were identified during the healing period or at the time of retrieval. New bone formation was more evident in groups 3 and 4 than in the other groups. A densitometric analysis of the calvarium at 8 weeks post-surgery showed the highest values in group 3.

CONCLUSIONS

This study showed that the highest regeneration was found when the stem cells were applied to synthetic bone along with a collagen matrix.

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.

Bi-allelic mutation in SEC16B alters collagen trafficking and increases ER stress

Osteogenesis imperfecta (OI) is a genetically and clinically heterogeneous disorder characterized by bone fragility and reduced bone mass generally caused by defects in type I collagen structure or defects in proteins interacting with collagen processing. We identified a homozygous missense mutation in SEC16B in a child with vertebral fractures, leg bowing, short stature, muscular hypotonia, and bone densitometric and histomorphometric features in keeping with OI with distinct ultrastructural features. In line with the putative function of SEC16B as a regulator of trafficking between the ER and the Golgi complex, we showed that patient fibroblasts accumulated type I procollagen in the ER and exhibited a general trafficking defect at the level of the ER. Consequently, patient fibroblasts exhibited ER stress, enhanced autophagosome formation, and higher levels of apoptosis. Transfection of wild-type SEC16B into patient cells rescued the collagen trafficking. Mechanistically, we show that the defect is a consequence of reduced SEC16B expression, rather than due to alterations in protein function. These data suggest SEC16B as a recessive candidate gene for OI.

The decisive early phase of bone regeneration

Bone has a remarkable endogenous regenerative capacity that enables scarless healing and restoration of its prior mechanical function, even under challenging conditions such as advanced age and metabolic or immunological degenerative diseases. However - despite much progress - a high number of bone injuries still heal with unsatisfactory outcomes. The mechanisms leading to impaired healing are heterogeneous, and involve exuberant and non-resolving immune reactions or overstrained mechanical conditions that affect the delicate regulation of the early initiation of scar-free healing. Every healing process begins phylogenetically with an inflammatory reaction, but its spatial and temporal intensity must be tightly controlled. Dysregulation of this inflammatory cascade directly affects the subsequent healing phases and hinders the healing progression. This Review discusses the complex processes underlying bone regeneration, focusing on the early healing phase and its highly dynamic environment, where vibrant changes in cellular and tissue composition alter the mechanical environment and thus affect the signalling pathways that orchestrate the healing process. Essential to scar-free healing is the interplay of various dynamic cascades that control timely resolution of local inflammation and tissue self-organization, while also providing sufficient local stability to initiate endogenous restoration. Various immunotherapy and mechanobiology-based therapy options are under investigation for promoting bone regeneration.

A New Osteogenic Membrane to Enhance Bone Healing: At the Crossroads between the Periosteum, the Induced Membrane, and the Diamond Concept

The lack of viability of massive bone allografts for critical-size bone defect treatment remains a challenge in orthopedic surgery. The literature has reviewed the advantages of a multi-combined treatment with the synergy of an osteoconductive extracellular matrix (ECM), osteogenic stem cells, and growth factors (GFs). Questions are still open about the need for ECM components, the influence of the decellularization process on the latter, the related potential loss of function, and the necessity of using pre-differentiated cells. In order to fill in this gap, a bone allograft surrounded by an osteogenic membrane made of a decellularized collagen matrix from human fascia lata and seeded with periosteal mesenchymal stem cells (PMSCs) was analyzed in terms of de-/recellularization, osteogenic properties, PMSC self-differentiation, and angiogenic potential. While the decellularization processes altered the ECM content differently, the main GF content was decreased in soft tissues but relatively increased in hard bone tissues. The spontaneous osteogenic differentiation was necessarily obtained through contact with a mineralized bone matrix. Trying to deepen the knowledge on the complex matrix-cell interplay could further propel these tissue engineering concepts and lead us to provide the biological elements that allow bone integration in vivo.

Strategies to Convert Cells into Hyaline Cartilage: Magic Spells for Adult Stem Cells

Damaged hyaline cartilage gradually decreases joint function and growing pain significantly reduces the quality of a patient’s life. The clinically approved procedure of autologous chondrocyte implantation (ACI) for treating knee cartilage lesions has several limits, including the absence of healthy articular cartilage tissues for cell isolation and difficulties related to the chondrocyte expansion in vitro. Today, various ACI modifications are being developed using autologous chondrocytes from alternative sources, such as the auricles, nose and ribs. Adult stem cells from different tissues are also of great interest due to their less traumatic material extraction and their innate abilities of active proliferation and chondrogenic differentiation. According to the different adult stem cell types and their origin, various strategies have been proposed for stem cell expansion and initiation of their chondrogenic differentiation. The current review presents the diversity in developing applied techniques based on autologous adult stem cell differentiation to hyaline cartilage tissue and targeted to articular cartilage damage therapy.