Fate of mesenchymal stem cells transplanted to osteonecrosis of femoral head

The bone microenvironment: new insights into the role of stem cells and cell communication in bone regeneration

Mesenchymal stem cells (MSCs) play a crucial role in bone formation and remodeling. Intrinsic genetic factors and extrinsic environmental cues regulate their differentiation into osteoblasts. Within the bone microenvironment, a complex network of biochemical and biomechanical signals orchestrates bone homeostasis and regeneration. In addition, the crosstalk among MSCs, immune cells, and neighboring cells-mediated by extracellular vesicles and non-coding RNAs (such as circular RNAs and micro RNAs) -profoundly influences osteogenic differentiation and bone remodeling. Recent studies have explored specific signaling pathways that contribute to effective bone regeneration, highlighting the potential of manipulating the bone microenvironment to enhance MSC functionality. The integration of advanced biomaterials, gene editing techniques, and controlled delivery systems is paving the way for more targeted and efficient regenerative therapies. Furthermore, artificial intelligence could improve bone tissue engineering, optimize biomaterial design, and enable personalized treatment strategies. This review explores the latest advancements in bone regeneration, emphasizing the intricate interplay among stem cells, immune cells, and signaling molecules. By providing a comprehensive overview of these mechanisms and their clinical implications, we aim to shed light on future research directions in this rapidly evolving field.

Assessing the Impact of a Modified Core Decompression Technique on Early-Stage Avascular Necrosis of the Hip Using Bone Marrow Concentrate Adjuvant Therapy: A Retrospective Study

BACKGROUND

Osteonecrosis is characterized by the necrosis of trabecular bone and cells within the femoral head, which often results in the subchondral collapse and deformation of the articulating surface of the head. For the treatment of early stages of this condition, specifically Stage I and Stage II, bone marrow-derived stem cells have been employed effectively for several years. In our approach, we have utilized a modified technique to collect bone marrow aspirate, which has yielded favorable outcomes.

METHODS

In our study, we performed surgeries on 32 hips afflicted with early-stage osteonecrosis of the femoral head. Each patient underwent core decompression and the injection of bone marrow concentrate, guided by C-arm imaging in the operating theater. Evaluations were conducted using the Harris Hip Score and the Visual Analogue Scale (VAS), along with radiological assessments to track the progression of osteonecrosis stages before and after the surgical procedure.

RESULTS

The comparison of pre- and post-surgery data, including the Harris Hip Score, VAS, progression of osteonecrosis stages, and radiological findings, revealed significantly positive outcomes. Since May 2013, 32 hips, regardless of the etiology of avascular necrosis (AVN), have been treated with this procedure. Notably, only four patients with bilateral AVN progressed to Stage III in one hip, while the other hip remained stable. In the remaining patients, pain was alleviated, and none progressed to later stages. No complications were observed in this study.

CONCLUSION

This minimally invasive technique, characterized by its simplicity and lack of associated complications or donor site morbidity, has proven to be an effective joint-preserving surgical intervention for early stages of femoral head osteonecrosis (Stages 1 and 2).

COVID-19-Associated Bilateral Avascular Necrosis of Femoral Head in a Young Male Without Corticosteroid Exposure: A Case Report

Avascular necrosis (AVN), also known as osteonecrosis, ischemic bone necrosis, or aseptic necrosis, is a progressive bone disease marked by the deterioration of bone tissue due to compromised blood flow in the subchondral region. AVN is typically caused by disruptions in vascular supply, intravascular blockages, or pressure on blood vessels, leading to diminished circulation. This condition predominantly affects the long-bone epiphysis in weight-bearing joints, particularly impacting the femoral head. The ongoing global health challenge posed by the novel coronavirus disease (COVID-19) has raised awareness of its diverse clinical manifestations. While pulmonary dysfunction remains a hallmark, reports of AVN of the hip have emerged in association with COVID-19 infection. Despite existing literature documenting cases of unilateral and bilateral femoral head necrosis associated with COVID-19 infection, it is noteworthy that corticosteroid use has been identified as a significant contributing factor to the development of this condition. Here, we present a case of bilateral AVN of the femoral head in a young individual linked solely to COVID-19 infection. Existing case records show only a handful of instances where COVID-19 has led to avascular necrosis, all involving either older individuals or those with notable risk factors. What sets our case apart is that the patient is young and lacks any significant risk factors. This report aims to propose a credible connection between COVID-19 infection and femoral head osteonecrosis in young patients not exposed to steroid treatment.

The pandemic is gone but its consequences are here to stay: avascular necrosis following corticosteroids administration for severe COVID-19

BACKGROUND

In patients with COVID-19 infection and respiratory insufficiency, corticosteroid (CCS) administration is recommended. Among the wide range of complications and interactions, time-limited high-dose CCS administration might promote avascular necrosis (AVN) in a cumulative dose. This systematic review updated the current evidence and characterises the trend of AVN following time-limited high-dose CCS administration in patients who had severe COVID-19, discussing management strategies and outcomes.

METHODS

This systematic review was conducted according to the 2020 PRISMA statement. In October 2023, the following databases were accessed: PubMed, Web of Science, Google Scholar, and Scopus restricting the search to the years 2019 to 2023. All the clinical studies which investigated the association between time-limited high-dose CCS administration in patients with severe COVID-19 infection and AVN were accessed.

RESULTS

A total of 245 patients (9 studies) who experienced AVN following COVID-19 were included in the present investigation. 26% (63 of 245 included patients) were women. The mean age of the patients was 42.9 ± 17.7 years. Four studies focused on AVN of the hip and two on the knee, and the other studies included patients with AVN from mixed areas of the body (spine, pelvis, and shoulder). The mean time elapsed from COVID-19 infection to the development of symptomatic AVN was 79.4 ± 59.2 days (range, 14 to 166 days).

CONCLUSION

It is possible that even time-limited high-dose CCS administration in patients with severe COVID-19 infection increased the incidence of AVN. The mean time elapsed from COVID-19 infection to the development of symptomatic AVN was approximately 80 days. Given the high risk of bias in all the included studies, the quality of recommendations of the present investigation is low, and no reliable conclusion can be inferred.

Preclinical models for studying corticosteroid-induced osteonecrosis of the femoral head

Nontraumatic osteonecrosis of the femoral head (ONFH) is a refractory condition that commonly results in femoral head collapse and degenerative arthritis of the hip. In the early stages, surgical procedures for hip preservation, including core decompression (CD), have been developed to prevent progressive collapse of the femoral head. Optimization of bone regeneration and biological augmentation may further enhance the therapeutic efficacy of CD for ONFH. Thus, combining CD with cell-based therapy has recently been proposed. In fact, patients treated with cell-based therapy using autologous bone marrow concentrate demonstrate improved survivorship of the femoral head, compared with conventional CD alone. Preclinical research studies to investigate adjunctive therapies for CD often utilize the rabbit model of corticosteroid-induced ONFH. Mesenchymal stem cells (MSCs) are known to promote osteogenesis and angiogenesis, and decrease inflammation in bone. Local drug delivery systems have the potential to achieve targeted therapeutic effects by precisely controlling the drug release rate. Scaffolds can provide an osteoconductive structural framework to facilitate the repair of osteonecrotic bone tissue. We focused on the combination of both cell-based and scaffold-based therapies for bone tissue regeneration in ONFH. We hypothesized that combining CD and osteoconductive scaffolds would provide mechanical strength and structural cell guidance; and that combining CD and genetically modified (GM) MSCs to express relevant cytokines, chemokines, and growth factors would promote bone tissue repair. We developed GM MSCs that overexpress the anti-inflammatory, pro-reconstructive cytokines platelet-derived growth factor-BB to provide MSCs with additional benefits and investigated the efficacy of combinations of these GM MSCs and scaffolds for treatment of ONFH in skeletally mature male New Zealand white rabbits. In the future, the long-term safety, efficacy, durability, and cost-effectiveness of these and other biological and mechanical treatments must be demonstrated for the patients affected by ONFH.

Effect of three clinical therapies on cytokines modulation in the hip articular cartilage and bone improvement in rat early osteonecrosis of the femoral head

BACKGROUND

Extracorporeal shockwave therapy (ESWT) and adipose-derived mesenchymal stem cells (ADSCs) have been used clinically for the treatment of osteonecrosis of the femoral head (ONFH). The study elucidated that ESWT, ADSCs, and combination therapy modulated pro-inflammatory cytokines in the articular cartilage and subchondral bone of early rat ONFH.

METHODS

ESWT and ADSCs were prepared and isolated for treatment. Micro-CT, pathological analysis, and immunohistochemistry were performed and analysed.

RESULTS

After treatments, subchondral bone of ONFH was improved in trabecular bone volume (BV/TV) (p < 0.001), thickness (Tb.Th) (p < 0.01 and 0.001), and separation (Tb.Sp) (p < 0.001) and bone mineral density (BMD) (p < 0.001) using micro-CT analysis. The articular cartilage was protected and decreased apoptosis markers after all the treatments. The expression of IL33 (p < 0.001), IL5 (p < 0.001), IL6 (p < 0.001), and IL17A (p < 0.01) was significantly decreased in the ESWT, ADSCs, and Combination groups as compared with ONFH group. The IL33 receptor ST2 was significantly increased after treatment (p < 0.001) as compared with ONFH group. The Combination group (p < 0.01) decreased the expression of IL6 better than the ESWT and ADSCs groups.

CONCLUSION

ESWT, ADSCs and combination therapy significantly protected articular cartilage and subchondral bone of early rat ONFH by modulating the expression of pro-inflammatory cytokines including, IL33 and its receptor ST2, IL5, IL6, and IL17A.

Extracellular vesicles from human umbilical cord mesenchymal stem cells prevent steroid-induced avascular necrosis of the femoral head via the PI3K/AKT pathway

Extracellular vesicles (EVs) secreted by human umbilical cord mesenchymal stem cells (hucMSC) have excellent therapeutic potential for many diseases. The aim of this study was to define the role of hucMSC-EVs in the prevention and treatment of steroid-induced avascular necrosis of the femoral head (SANFH). After establishing the SANFH rat model, the effects of hucMSC-EVs were assessed by measuring the microstructure of the femoral head using HE staining, micro-computed tomography (micro-CT), and TUNEL staining. The administration of hucMSC-EVs caused a significant reduction to glucocorticoids (GCs)-induced osteoblast apoptosis and empty lacuna of the femoral head, while effectively improving the microstructure. HucMSC-EVs rescued the deactivation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway induced by GCs, and reversed the proliferation and migration of osteoblasts inhibited by GCs. In addition, hucMSC-EVs attenuated the inhibitory effects of GCs on rat osteoblast osteogenesis, angiogenesis of endothelial cells, and prevented osteoblast apoptosis. However, the promoting effects of hucMSC-EVs were abolished following the blockade of PI3K/AKT on osteoblasts. hucMSC-EVs were found to prevent glucocorticoid-induced femoral head necrosis in rats through the PI3K/AKT pathway.

Prognostic factors in the management of osteonecrosis of the femoral head: A systematic review

BACKGROUND

Several hip preserving techniques have been described for the management of osteonecrosis of the femoral head (ONFH). This systematic review identified prognostic factors in the treatment of ONFH that are associated with treatment failure and conversion to total hip arthroplasty (THA).

MATERIAL AND METHODS

This study followed the PRISMA guidelines. The literature search was conducted in November 2021. All clinical trials comparing two or more treatments for femoral head osteonecrosis were accessed. A multivariate analysis was performed to investigate the association between baseline characteristics and the surgical outcome. A multiple linear model regression analysis through the Pearson Product-Moment Correlation Coefficient (r) was used.

RESULTS

Data from 88 articles (6112 procedures) were retrieved. Female gender was associated with increased time to THA (P = 0.03) and reduced rate of THA (P = 0.03). Longer symptom duration before treatment was associated with shorter time to failure (P = 0.03). Increased pre-treatment VAS was associated with reduced time to failure (P = 0.03) and time to THA (P = 0.04). Reduced pre-treatment hip function was associated with increased rate of THA (P = 0.02) and failure (P = 0.005). Patient age and BMI, aetiology, time from surgery to full weight bearing and the side did not show evidence of a statistically significant association with the surgical outcome.

CONCLUSION

Male gender, longer symptom duration before treatment, higher VAS scores, and lower HHS scores were negative prognostic factors after treatment for osteonecrosis of the femoral head.

Engineering exosomes and biomaterial-assisted exosomes as therapeutic carriers for bone regeneration

Mesenchymal stem cell-based therapy has become an effective therapeutic approach for bone regeneration. However, there are still limitations in successful clinical translation. Recently, the secretome of mesenchymal stem cells, especially exosome, plays a critical role in promoting bone repair and regeneration. Exosomes are nanosized, lipid bilayer-enclosed structures carrying proteins, lipids, RNAs, metabolites, growth factors, and cytokines and have attracted great attention for their potential application in bone regenerative medicine. In addition, preconditioning of parental cells and exosome engineering can enhance the regenerative potential of exosomes for treating bone defects. Moreover, with recent advancements in various biomaterials to enhance the therapeutic functions of exosomes, biomaterial-assisted exosomes have become a promising strategy for bone regeneration. This review discusses different insights regarding the roles of exosomes in bone regeneration and summarizes the applications of engineering exosomes and biomaterial-assisted exosomes as safe and versatile bone regeneration agent delivery platforms. The current hurdles of transitioning exosomes from bench to bedside are also discussed.

Analysis of the potential biological mechanisms of Danyu Gukang Pill against osteonecrosis of the femoral head based on network pharmacology

BACKGROUND

Osteonecrosis of the femoral head (ONFH) is still a challenge for orthopedists worldwide and can lead to disability if patients are not treated effectively. Danyu Gukang Pill (DGP), a traditional Chinese medicine (TCM) formulation, is recognized to be effective against ONFH. Nevertheless, its molecular mechanisms remain to be clarified.

METHODS

The active ingredients of DGP were collected from the online databases according to oral bioavailability (OB) and drug-likeness (DL). The potential targets of DGP were retrieved from the TCMSP database, while the potential targets of ONFH were obtained from the GeneCards and NCBI databases. The functions and signaling pathways of the common targets of DGP and ONFH were enriched by GO and KEGG analyses. Subsequently, molecular docking and in vitro cell experiments were performed to further validate our findings.

RESULTS

In total, 244 active ingredients of DGP and their corresponding 317 targets were obtained, and 40 ONFH-related targets were predicted. Afterwards, 19 common targets of DGP and ONFH were obtained and used as potential targets for the treatment of ONFH. Finally, combined with network pharmacology analysis, molecular docking and in vitro cell experiments, our study first demonstrated that the treatment effect of DGP on ONFH might be closely related to the two targets, HIF1A (HIF-1α) and VEGFA, and the HIF-1 signaling pathway.

CONCLUSIONS

This study is the first to investigate the molecular mechanisms of DGP in the treatment of ONFH based on network pharmacology. The results showed that DGP might up-regulate the expression of HIF-1α and VEGFA by participating in the HIF-1 signaling pathway, thus playing an anti-ONFH role.

Autologous hematopoietic bone marrow and concentrated growth factor transplantation combined with core decompression in patients with avascular necrosis of the femoral head

The study aimed to assess the effectiveness of autologous hematopoietic bone marrow and concentrated growth factor (CGF) transplantation and core decompression in patients with avascular necrosis of the femoral head (ANFH). We performed a single-center prospective study on 31 patients with non-traumatic early-stage (stage I to III) ANFH based on the 1994 classification of the Association Research Circulation Osseous (ARCO). The patients were subjected to bone marrow aspiration from the posterior iliac crest, separation, and concentration of growth factors from the bone marrow aspirate, core decompression of the femoral head, and injection of hematopoietic bone marrow and CGFs into the necrotic lesion. Patients were evaluated using the visual analogue scale, the WOMAC questionnaire, and X-ray and MRI examinations of the hip joints before, at 2, 4, and 6 months after the intervention. Patients had a mean age of 33 years (range 20-44 years), 19 (61%) of them being male and 12 (39%) females. The presentation of the disease was bilateral in 21 patients and unilateral in 10 patients. The main cause of ANFH was steroid treatment. The mean VAS and WOMAC scores were 48.37 (SD: 14.67) out of 100, and the mean VAS pain score was 50.83 out of 100 (SD: 20.46), respectively, before transplant. This value significantly improved to 22.31 (SD 12.12) of 100, and the mean VAS pain score was 21.31 of 100 (SD: 20.46) (P=0.04). MRI showed a significant improvement (P=0.012). Our results suggest that autologous hematopoietic bone marrow and CGFs transplantation with core decompression have a beneficial effect in early-stage ANFH.

The potential effect of BMSCs with miR-27a in improving steroid-induced osteonecrosis of the femoral head

Steroid induced osteonecrosis of the femoral head (ONFH) frequently leads to femoral head collapse and subsequent hip arthritis. This study aimed to investigate the potential therapeutic mechanism of miR-27a on steroid-induced ONFH. Levels of IL-6, TNF-α, miR-27a, Runx2, PPAR-γ and ApoA5 were first examined in bone marrow tissues from steroid-induced ONFH and controls. Subsequently, we overexpressed or knocked down miR-27a in bone marrow mesenchymal stem cells (BMSCs) and detected cell proliferation, osteogenic differentiation, adipogenic differentiation. In addition, miR-27a mimics and BMSCs were injected into the established steroid-induced ONFH rats, and the osteoprotective effects of both were evaluated. Dual luciferase reporter was used to test the targeting effect of miR-27a-3p and PPARG. miR-27a and Runx2 were lowly expressed in steroid-induced ONFH, PPAR-γ and ApoA5 were highly expressed. Overexpression of miR-27a in BMSCs promoted cell proliferation and osteogenic differentiation, inhibited adipogenic differentiation. Furthermore, increasing miR-27a and BMSCs obviously reduced bone loss in steroid induced ONFH rats. The expressions of Runx2 in BMSCs and steroid-induced ONFH rats was significantly up-regulated, while IL-6, TNF-α, PPAR-γ and ApoA5 were down-regulated with miR-27a overexpression. Additionally, PPARG was the target of miR-27a-3p. The results of the present study reveal a role for miR-27a in promoting osteogenesis and may have a synergistic effect with BMSCs.

Mesenchymal stem cells for subchondral bone marrow lesions: From bench to bedside

Subchondral bone marrow lesions (BMLs) are areas of disease within subchondral bone that appear as T1 hypointense and T2 hyperintense ill-defined areas of bone marrow on magnetic resonance imaging. The most common bone marrow lesions include subchondral lesions related to osteoarthritis, osteochondral defects, and avascular necrosis. Emerging therapies include autologous biologic therapeutics, in particular mesenchymal stem cells (MSCs), to maintain and improve cartilage health; MSCs have become a potential treatment option for BMLs given the unmet need for disease modification. Active areas in the preclinical research of bone marrow lesions include the paracrine function of MSCs in pathways of angiogenesis and inflammation, and the use of bioactive scaffolds to optimize the environment for implanted MSCs by facilitating chondrogenesis and higher bone volumes. A review of the clinical data demonstrates improvements in pain and functional outcomes when patients with knee osteoarthritis were treated with MSCs, suggesting that BM-MSCs can be a safe and effective treatment for patients with painful knee osteoarthritis with or without bone marrow lesions. Preliminary data examining MSCs in osteochondral defects suggest they can be beneficial as a subchondral injection alone, or as a surgical augmentation. In patients with hip avascular necrosis, those with earlier stage disease have improved outcomes when core decompression is augmented with MSCs, whereas patients in later stages post-collapse have equivalent outcomes with or without MSC treatment. While the evidence for the use of MSCs in conditions with associated bone marrow lesions seems promising, there remains a need for continued investigation into this treatment as a viable treatment option.

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Common BMLs include osteoarthritis, osteochondral defects, and avascular necrosis.

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Patients with knee osteoarthritis treated with MSCs show improved pain and function.

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MSCs used as subchondral injection or surgical augmentation in osteochondral defects

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Improved outcomes of early hip avascular necrosis after core decompression with MSCs

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Additional preclinical and clinical evidence of MSCs as treatment for BMLs is needed.

Bone Marrow Mesenchymal Stem Cells Overexpressing HIF-1α Prevented the Progression of Glucocorticoid-Induced Avascular Osteonecrosis of Femoral Heads in Mice

Glucocorticoid (GC)-induced avascular osteonecrosis of femoral head (AOFH) is a devastating complication, and no cures are currently available for it. Previous studies have demonstrated that implantation of bone marrow mesenchymal stem cells (BMMSCs) may prevent the progression of pre-collapse AOFH. Based on previous observations, we hypothesized that GCs induce AOFH via the COX-2 (cyclooxygenase-2)-PGE-2 (prostaglandin E2)-HIF-1α (hypoxia-inducible factor-1α) axis, and that modification of BMMSCs may improve the efficacy of their implantation. BMMSCs isolated from wild-type (WT) mice were treated with dexamethasone (Dex) and the results showed that Dex repressed the expression of COX-2. Femoral head samples harvested from both WT and COX-2 knock-out (COX-2^-/-) mice were subjected to micro-computed tomography and histological examinations. Compared with their WT littermates, COX-2^-/- mice had larger trabecular separations, diminished microvasculature, and reduced HIF-1α expression in their femoral heads. In vitro angiogenesis assays with tube formation and fetal metatarsal sprouting demonstrated that Dex repressed angiogenesis and PGE-2 antagonized its effects. An AOFH model was successfully established in C57BL/6J mice. In vitro experiment showed that BMMSCs infected with Lentivirus encoding HIF-1α (Lenti-HIF-1α) resulted in a robust increase in the production of HIF-1α protein. Implantation of BMMSCs overexpressing HIF-1α into femoral heads of AOFH mice significantly reduced osteonecrotic areas and enhanced bone repair, thus largely preserving the structural integrity of femoral heads. Our studies provide strong rationales for early intervention with core decompression and implantation of modified BMMSCs for GC-induced AOFH, which may spare patients from expensive and difficult surgical procedures.

Evolutionary course of the femoral head osteonecrosis: Histopathological - radiologic characteristics and clinical staging systems

Osteonecrosis of the femoral head (ONFH) is a recalcitrant ischemic disorder, which could be classified into two major categories: traumatic and nontraumatic. Regardless of different risk factors, it has been testified that ONFH results from primitive vascular problems, leading to temporary or permanent loss of blood supply to bone tissue. Histopathological and microarchitectural alterations ensues, which is a gradual evolutionary process involving bone marrow and osteocyte necrosis, progressive destruction of subchondral bone, unsuccessful reparative process, and eventual articular collapse and degenerative arthritis. Based on the imaging features of ONFH, different classification systems have been developed to evaluate the severity and prognosis of the disease, which is pivotal for implementation of treatment strategy, especially the joint-preserving surgery. However, patients classified with the same severity stage, especially in the peri-collapse stage, sometimes responded differently after similar joint-preserving surgery. The unusual phenomenon may be attributed to the limitation of the current imaging classification systems, which might underestimate the disease severity, especially when referring to the early stages. In this review, we briefly summarize the etiology and pathogenesis of ONFH. The imaging features and staging classification systems of ONFH are also described. More importantly, we focus on histopathological and microstructural alterations of the femoral head, and provide an overview of their essential contribution to ONFH progression. Given the observation of discordance between imaging characteristics and histopathological alterations, a substantial amount of research on the relationship between imaging and histopathological features is required to further modify and revise the current wide-accepted classification systems.

Culture and characterization of various porcine integumentary-connective tissue-derived mesenchymal stromal cells to facilitate tissue adhesion to percutaneous metal implants

Background

Transdermal osseointegrated prosthesis have relatively high infection rates leading to implant revision or failure. A principle cause for this complication is the absence of a durable impervious biomechanical seal at the interface of the hard structure (implant) and adjacent soft tissues. This study explores the possibility of recapitulating an analogous cellular musculoskeletal-connective tissue interface, which is present at naturally occurring integumentary tissues where a hard structure exits the skin, such as the nail bed, hoof, and tooth.

Methods

Porcine mesenchymal stromal cells (pMSCs) were derived from nine different porcine integumentary and connective tissues: hoof-associated superficial flexor tendon, molar-associated periodontal ligament, Achilles tendon, adipose tissue and skin dermis from the hind limb and abdominal regions, bone marrow and muscle. For all nine pMSCs, the phenotype, multi-lineage differentiation potential and their adhesiveness to clinical grade titanium was characterized. Transcriptomic analysis of 11 common genes encoding cytoskeletal proteins VIM (Vimentin), cell–cell and cell–matrix adhesion genes (Vinculin, Integrin β1, Integrin β2, CD9, CD151), and for ECM genes (Collagen-1a1, Collagen-4a1, Fibronectin, Laminin-α5, Contactin-3) in early passaged cells was performed using qRT-PCR.

Results

All tissue-derived pMSCs were characterized as mesenchymal origin by adherence to plastic, expression of cell surface markers including CD29, CD44, CD90, and CD105, and lack of hematopoietic (CD11b) and endothelial (CD31) markers. All pMSCs differentiated into osteoblasts, adipocytes and chondrocytes, albeit at varying degrees, under specific culture conditions. Among the eleven adhesion genes evaluated, the cytoskeletal intermediate filament vimentin was found highly expressed in pMSC isolated from all tissues, followed by genes for the extracellular matrix proteins Fibronectin and Collagen-1a1. Expression of Vimentin was the highest in Achilles tendon, while Fibronectin and Col1agen-1a1 were highest in molar and hoof-associated superficial flexor tendon bone marrow, respectively. Achilles tendon ranked the highest in both multilineage differentiation and adhesion assessments to titanium metal.

Conclusions

These findings support further preclinical research of these tissue specific-derived MSCs in vivo in a transdermal osseointegration implant model.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02666-2.

Cell therapy for osteonecrosis of femoral head and joint preservation

Osteonecrosis of femoral head (ONFH) is a disease of the femoral head and can cause femoral head collapse and arthritis. This can lead to pain and gait disorders. ONFH has various risk factors, it is often progressive, and if untreated results in secondary osteo-arthritis. Biological therapy makes use of bone marrow concentrate, cultured osteoblast and mesenchymal stem cell (MSC) obtained from various sources. These are often used in conjunction with core decompression surgery. In this review article, we discuss the current status of cell therapy and its limitations. We also present the future development of biological approach to treat ONFH.

Protective Effect of Human Umbilical Cord Mesenchymal Stem Cells in Glucocorticoid-induced Osteonecrosis of Femoral Head

OBJECTIVE

To evaluate the effect of human umbilical cord mesenchymal stem cells (hUC-MSCs) on preventing rats from glucocorticoid-induced osteonecrosis of femoral head (GCONFH) in the early stage in vivo and to investigate the possible mechanism of hUC-MSCs in regulating the balance of osteogenesis and adipogenesis.

METHODS

All rats were randomly divided into 3 groups: control group (C group), model group (M group), and intervention group (I group). The model of GC-ONFH was developed by a sequential administration of lipopolysaccharide and methylprednisolone. The rats in the I group were treated with caudal vein injection of hUC-MSCs. Six weeks later, the blood samples were obtained to measure the activity of alkaline phosphatase (ALP) and the content of triglyceride (TG) in serum, and the femoral heads were harvested and observed by hematoxylin-eosin staining, Micro-CT, Western blot and real-time quantitative polymerase chain reaction.

RESULTS

After intervention of hUC-MSCs, the necrosis rate of femoral head decreased from 83% (10/12) to 33% (4/12), the rate of empty bone lacuna was significantly decreased, the activity of ALP increased significantly, the content of TG decreased significantly, the bone density increased obviously, the expression of RUNX2 and Col I increased significantly and the expression of PPARγ decreased significantly.

CONCLUSION

These results revealed that caudal vein injection of hUC-MSCs can effectively reduce the incidence of GC-ONFH in rats by increasing ALP activity and reducing TG content in serum, increasing bone mineral density, promoting the expression of RUNX2 and Col I, and inhibiting the expression of PPARγ.

Current Status on Canine Foetal Fluid and Adnexa Derived Mesenchymal Stem Cells

Effective standards of care treatment guidelines have been developed for many canine diseases. However, a subpopulation of patients is partially or completely refractory to these protocols, so their owners seek novel therapies such as treatments with MSCs. Although in dogs, as with human medicine, the most studied MSCs sources have been bone marrow and adipose tissue, in recent years, many researchers have drawn attention towards alternative sources, such as foetal adnexa and fluid, since they possess many advantages over bone marrow and adipose tissue. Foetal adnexa and fluid could be considered as discarded material; therefore, sampling is non-invasive, inexpensive and free from ethical considerations. Furthermore, MSCs derived from foetal adnexa and fluid preserve some of the characteristics of the primitive embryonic layers from which they originate and seem to present immune-modulatory properties that make them a good candidate for allo- and xenotransplantation. The aim of the present review is to offer an update on the state of the art on canine MSCs derived from foetal adnexa and fluid focusing on the findings in their clinical setting.

Failure and progression to total hip arthroplasty among the treatments for femoral head osteonecrosis: a Bayesian network meta-analysis

INTRODUCTION

Osteonecrosis of the femoral head (ONFH) often leads to secondary osteoarthritis and total hip arthroplasty.

SOURCE OF DATA

Recent published literatures.

AREAS OF AGREEMENT

There has been increasing focus on the early intervention in ONFH patients to preserve the native hip articulation, reduce pain and improve function.

AREAS OF CONTROVERSY

Efficacy of surgical strategies for ONFH is debated. Several clinical studies showed controversial results, and the best treatment has not yet been clarified.

GROWING POINTS

To provide an overview over current treatment options for ONFH compares their failure rates and conversion to total hip arthroplasty (THA) rates.

AREAS TIMELY FOR DEVELOPING RESEARCH

Core decompression (CD) augmented with autologous bone grafting plus the implantation of bone marrow concentrate can decrease the rate of failure and progression to THA rates compared to CD alone.

Core decompression isolated or combined with bone marrow-derived cell therapies for femoral head osteonecrosis

Objectives: The regenerative capabilities of bone marrow-derived cell therapies (BMCTs) have been employed in combination with core decompression (CD) in the management of osteonecrosis of the femoral head to prevent or delay the necessity of total hip arthroplasty (THA).Methods: The authors conducted a meta-analysis to compare the results of level of evidence I trials comparing CD with and without BMCTs.Results: Overall, 579 procedures were analyzed: 265 in the CD group and 263 in the CD + BMCTs group. Comparability concerning age and gender, drill size, etiology, and grade of OFNH was found (P > 0.1). At a mean follow up of 82.29 (24 to 360) months, the VAS scored favourably for the CD + BMCTs group (mean difference: -12.88; P < 0.0001), as well the rate of THA (odd ratio: -0.14; P < 0.0001). Time to failure (P = 0.4) and to THA (P = 0.9) was similar between the two groups, as was the rate of failure (P = 0.3).Conclusion: In patients with femoral head osteonecrosis, core decompression combined with BMCTs demonstrated reduced pain and lower rate of total hip arthroplasty compared to core decompression as an isolated procedure.

Culture-Expanded Autologous Adipose-Derived Mesenchymal Stem Cell Treatment for Osteonecrosis of the Femoral Head

Backgroud

Outcomes of traditional treatment for osteonecrosis of the femoral head (ONFH) are not always satisfactory. Hence, cell-supplementation therapy has been attempted to facilitate necrotic-tissue regeneration. Adipose-derived mesenchymal stem cell (ADMSC) transplantation is potentially advantageous over bone marrow-derived MSC implantation, but its outcomes for ONFH remain unclear. The aim of this study was to determine 2-year radiological and clinical outcomes of culture-expanded autologous ADMSC implantation for ONFH.

Methods

Eighteen hips with necrotic lesions involving ≥ 30% of the femoral head were included. ADMSCs were harvested by liposuction and culture expanded for 3 passages over 3 weeks. With a 6-mm single drilling, ADMSCs were implanted into the necrotic zone. All patients underwent magnetic resonance imaging (MRI), single-photon emission computed tomography/computed tomography (SPECT/CT) at screening and 6 months, 12 months, and 24 months postoperatively. The primary outcome was the change in the size of necrotic area on MRI. Secondary outcomes were changes in clinical scores and radioisotope uptake on SPECT/CT. Conversion total hip arthroplasty (THA) was defined as the endpoint.

Results

Preoperatively, the necrotic lesion extent was 63.0% (38.4%–96.7%) of the femoral head. The mean Harris hip score was 89.2, the University of California at Los Angeles (UCLA) score was 5.6, and Western Ontario and McMaster Universities Arthritis index (WOMAC) was 79.4. Three patients underwent THA and 1 patient died in an accident. Finally, 11 patients (14 hips) were available for ≥ 2-year follow-up. At the last follow-up, no surgery-related complications occurred, and 14 of 17 hips (82%) were able to perform daily activities without THA requirement. There was no significant decrease in lesion size between any 2 intervals on MRI. However, widening of high signal intensity bands on T2-weighted images inside the necrotic lesion was observed in 9 of 14 hips (64%); 11 of 14 hips (79%) showed increased vascularity on SPECT/CT at 2 years postoperatively. No significant differences were observed between preoperative and 24-month mean Harris hip score (89.2 vs. 88.6), WOMAC (79.4 vs. 75.7), and UCLA score (5.6 vs. 6.2).

Conclusions

Our outcomes suggest that culture-expanded ADMSC implantation is a viable option for ONFH treatment without adverse events.

Administration of mircoRNA-135b-reinforced exosomes derived from MSCs ameliorates glucocorticoid-induced osteonecrosis of femoral head (ONFH) in rats

Exosomes were found to exert a therapeutic effect in the treatment of osteonecrosis of the femoral head (ONFH), while miR-135b was shown to play an important role in the development of ONFH. In this study, we investigated the effects of concomitant administration of exosomes and miR-135b on the treatment of ONFH. A rat mode of ONFH was established. TEM, Western blotting and nanoparticle analysis were used to characterize the exosomes collected from human-induced pluripotent stem cell-derived mesenchymal stem cells (hiPS-MSC-Exos). Micro-CT was used to observe the trabecular bone structure of the femoral head. Real-time PCR, Western blot analysis, IHC assay, TUNEL assay, MTT assay and flow cytometry were performed to detect the effect of hiPS-MSC-Exos and miR-135b on cell apoptosis and the expression of PDCD4/caspase-3/OCN. Moreover, computational analysis and luciferase assay were conducted to identify the regulatory relationship between PDCD4 mRNA and miR-135b. The hiPS-MSC-Exos collected in this study displayed a spheroidal morphology with sizes ranging from 20 to 100 nm and a mean concentration of 1 × 1012 particles/mL. During the treatment of ONFH, the administration of hiPS-MSC-Exos and miR-135b alleviated the magnitude of bone loss. Furthermore, the treatment of MG-63 and U-2 cells with hiPS-MSC-Exos and miR-135b could promote cell proliferation and inhibit cell apoptosis. Moreover, PDCD4 mRNA was identified as a virtual target gene of miR-135b. HiPS-MSC-Exos exerted positive effects during the treatment of ONFH, and the administration of miR-135b could reinforce the effect of hiPS-MSC-Exos by inhibiting the expression of PDCD4.

Bone marrow mesenchymal stem cell-derived exosomes promote plasminogen activator inhibitor 1 expression in vascular cells in the local microenvironment during rabbit osteonecrosis of the femoral head

Background

Nontraumatic osteonecrosis of the femoral head (NONFH) is a highly disabling orthopedic disease in young individuals. Plasminogen activator inhibitor 1 (PAI-1) has been reported to be positively associated with NONFH. We aimed to investigate the dysregulating PAI-1 in bone marrow mesenchymal stem cells (BMMSCs) and vascular cells in rabbit steroid-induced NONFH.

Methods

To verify the hypothesis that BMMSCs could promote thrombus formation in a paracrine manner, we collected exosomes from glucocorticoid-treated BMMSCs (GB-Exo) to determine their regulatory effects on vascular cells. microRNA sequencing was conducted to find potential regulators in GB-Exo. Utilizing gain-of-function and knockdown approaches, we testified the regulatory effect of microRNA in exosomes.

Results

The expression of PAI-1 was significantly increased in the local microenvironment of the femoral head in the ONFH model. GB-Exo promoted PAI-1 expression in vascular smooth muscle cells and vascular endothelial cells. We also revealed that miR-451-5p in GB-Exo plays a crucial role for the elevated PAI-1. Moreover, we identified miR-133b-3p and tested its role as a potential inhibitor of PAI-1.

Conclusions

This study provided considerable evidence for BMMSC exosomal miR-mediated upregulation of the fibrinolytic regulator PAI-1 in vascular cells. The disruption of coagulation and low fibrinolysis in the femoral head will eventually lead to a disturbance in the microcirculation of NONFH. We believe that our findings could be of great significance for guiding clinical trials in the future.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-020-01991-2.

Bone Microvasculature: Stimulus for Tissue Function and Regeneration

Bone is a highly vascularized organ, providing structural support to the body, and its development, regeneration, and remodeling depend on the microvascular homeostasis. Loss or impairment of vascular function can develop diseases, such as large bone defects, avascular necrosis, osteoporosis, osteoarthritis, and osteopetrosis. In this review, we summarize how vasculature controls bone development and homeostasis in normal and disease cases. A better understanding of this process will facilitate the development of novel disease treatments that promote bone regeneration and remodeling. Specifically, approaches based on tissue engineering components, such as stem cells and growth factors, have demonstrated the capacity to induce bone microvasculature regeneration and mineralization. This knowledge will have relevant clinical implications for the treatment of bone disorders by developing novel pharmaceutical approaches and bone grafts. Finally, the tissue engineering approaches incorporating vascular components may widely be applied to treat other organ diseases by enhancing their regeneration capacity. Impact statement Bone vasculature is imperative in the process of bone development, regeneration, and remodeling. Alterations or disruption of the bone vasculature leads to loss of bone homeostasis and the development of bone diseases. In this study, we review the role of vasculature on bone diseases and how vascular tissue engineering strategies, with a detailed emphasis on the role of stem cells and growth factors, will contribute to bone therapeutics.

Mesenchymal stem cells-derived and siRNAs-encapsulated exosomes inhibit osteonecrosis of the femoral head

Osteonecrosis of the femoral head (ONFH) is a progressive, obstinate and disabling disease. At present, the treatment of ONFH is still a global medical problem. We aim to explore the role of bone mesenchymal stem cells (BMSCs)‐derived and siRNAs‐encapsulated exosomes (siRNAs‐encapsulated BMSCexos) in ONFH. We first isolated BMSCexos and screened siRNAs of 6 ONFH‐related genes for siRNAs‐encapsulated BMSCexo. The expression of these 6 ONFH‐related genes in dexamethasone (DXM)‐treated MC3T3‐E1 cell, cell model of ONFH, was detected by RT‐qPCR and Western blot analysis. And then, we performed CCK‐8 assay, angiogenesis assay and HE staining analysis to test the promotion role of the siRNAs‐encapsulated BMSCexo for angiogenesis during ONFH repair. The results suggest that the obtained particles were BMSCexos. The screened effective siRNAs could effectively knock down their expression in VECs. Moreover, siRNAs‐encapsulated BMSCexo could effectively knock down the expression of these genes in VECs. In addition, siRNAs‐encapsulated BMSCexo promote angiogenesis during ONFH repair. In conclusion, we found siRNAs‐encapsulated BMSCexos could promote ONFH repair by angiogenesis, and indicated exosome as the new siRNA carrier is of great significance to improve the efficiency of RNAi.

Autologous grafts in the treatment of avascular osteonecrosis of the femoral head

Background:

Osteonecrosis of the femoral head (ONFH) is a frequent orthopedic disease leading to destruction of the hip joint and disabling arthritis. Several procedures have been developed to treat the joint deterioration in case of osteonecrosis, trying to avoid or delay an intervention of total hip replacement, especially in young patients. The aim of this study was to analyze the use of autologous bone micrografts derived from cancellous bone in the management of avascular ONFH. The treatment described was implemented using the Rigenera® protocol to obtain autologous micrografts: small fragments of cancellous bone collected by femoral neck, disaggregated and injected in the necrotic area using an empty screw.

Materials and methods:

Twenty adult patients affected by avascular ONFH were enrolled in this study; all patients reported a preoperative intermittent coxo-arthrosis and limited function of intra and extra rotation of the hip. Inclusion criteria were an Oxford Hip Score between (OHS) 20 and 39, a Harris hip score (HHS) showing pre-operative poor results (lower than 70 points) and a stage II-IIIA and IIIB according with the classification proposed by the Association Research Circulation Osseous (ARCO).

Results:

Using an MRI evaluation, after six months, the authors observed a complete regression of necrotic area and the restoration of osseous structure. Clinical outcome has been evaluated at 6-12 and 24 months follow-up. At the final F.U. the HHS rised from poor to good results (mean value at final F.U of 84) while the OHS improved significantly already after 21 days from micrografts injection (mean 35.4 ± 7.5) with an increasing trend until to two-year final FU (mean 37.4 ± 9.5). The full recovery of daily and mild sport activities was reached after 20 and 90 days from intervention, respectively.

Conclusion:

The results of this study are suggestive for a new approach in the treatment of avascular ONFH assuming a process of bone regeneration based on a dual mechanism of action, biological and mechanical, induced by micrografts and injected using an empty screw as vehicle. (www.actabiomedica.it)

Effect of Allogeneic Cell-Based Tissue-Engineered Treatments in a Sheep Osteonecrosis Model

Osteonecrosis of the femoral head (ONFH) is defined as a tissue disorder and successive subchondral bone collapse resulting from an ischemic process, which may progress to hip osteoarthritis. Cell therapy with multipotent bone marrow mesenchymal stromal cells (BM-MSC) of autologous origin appears to be safe and has shown regenerative potential in previous preclinical and clinical studies. The use of allogeneic cells is far more challenging, but may be a promising alternative to use of autologous cells. Moreover, an optimized dosage of cells from an allogeneic source is needed to obtain off-the-shelf tissue engineering products (TEPs). The purpose of this study was to evaluate the efficacy of a TEP composed of undifferentiated ex vivo expanded BM-MSC of allogeneic origin, combined with bone matrix particles in variable doses. A comparative analysis of TEP's bone regenerative properties against its autologous counterpart was performed in an early-stage ONFH preclinical model in mature sheep. Allogeneic BM-MSC groups demonstrated bone regeneration capacity in osteonecrotic lesions equivalent to autologous BM-MSC groups 6 weeks after treatment. Likewise, stimulation of bone regeneration by a low cell dose of 0.5 × 10⁶ BM-MSC/cm³ was equivalent to that of a high cell dose, 5 × 10⁶ BM-MSC/cm³. Neither local nor systemic immunological reactions nor tumorigenesis were reported, strengthening the safety profile of allogeneic BM-MSC therapy in this model. Our results suggest that low-dose allogeneic BM-MSC is sufficient to promote bone regeneration in femoral head osteonecrotic lesions, and should be considered in translation of new allogeneic cell-based TEPs to human clinics. Impact statement Cell therapy and tissue engineering hold promise as novel regenerative therapies for musculoskeletal diseases, and particularly in bone regeneration strategies. In this article, we report the evaluation of the efficacy of an allogeneic cell-based tissue engineering product (TEP) in an early-stage osteonecrosis of the femoral head preclinical model in skeletally mature sheep. Moreover, we demonstrate its bone regeneration capacity and safety in vivo and its equivalence to autologous counterparts. These findings have important implications for the translation of new allogeneic cell-based TEPs to human clinics.

Therapeutic Applications of Genes and Gene-Engineered Mesenchymal Stem Cells for Femoral Head Necrosis

Osteonecrosis of the femoral head (ONFH) is a common and disabling joint disease. Although there is no clear consensus on the complex pathogenic mechanism of ONFH, trauma, abuse of glucocorticoids, and alcoholism are implicated in its etiology. The therapeutic strategies are still limited, and the clinical outcomes are not satisfactory. Mesenchymal stem cells (MSCs) have been shown to exert a positive impact on ONFH in preclinical experiments and clinical trials. The beneficial properties of MSCs are due, at least in part, to their ability to home to the injured tissue, secretion of paracrine signaling molecules, and multipotentiality. Nevertheless, the regenerative capacity of transplanted cells is impaired by the hostile environment of necrotic tissue in vivo, limiting their clinical efficacy. Recently, genetic engineering has been introduced as an attractive strategy to improve the regenerative properties of MSCs in the treatment of early-stage ONFH. This review summarizes the function of several genes used in the engineering of MSCs for the treatment of ONFH. Further, current challenges and future perspectives of genetic manipulation of MSCs are discussed. The notion of genetically engineered MSCs functioning as a "factory" that can produce a significant amount of multipotent and patient-specific therapeutic product is emphasized.

A Mini Review: Stem Cell Therapy for Osteonecrosis of the Femoral Head and Pharmacological Aspects

Osteonecrosis of the femoral head (ONFH) is a common disease that occurs frequently. Due to various etiologies, the blood supply directed to the femoral head is interrupted in patients with ONFH. This disease can result in degeneration and necrosis of the subchondral bone of the femoral head, which ultimately cause a collapse of the femoral head. Of note, ONFH can extremely affect the quality of living of patients with a high disability rate. Also, this disease often includes middle-aged and younger people. However, effective treatments of ONFH are still challenging in clinics. In recent years, stem cells have been profoundly studied and a relevant new technology has been developed rapidly and applied for regenerative medicine. A number of reports have demonstrated successful results of the treatment of ONFH by using stem cell transplantation. By the combination of minimally invasive hip decompression and injection of mesenchymal stem cells into the necrotic lesion, the retrospective analysis of patients treated revealed that significant pain relief was observed in 86% patients and they had no major complications after treatment. Thus, stem cell transplantation is anticipated to be applied as an innovative approach in the treatment of ONFH. This review will summarize results obtained from recent human and animal studies, which include the pathophysiological process of ONFH, current techniques and effects of using stem cells on the treatment of ONFH together with pharmacological aspects. Overall, the current evidence reveals the treatment of ONFH using stem cell technology as promising. Nonetheless, additional in-depth studies are necessary to better explore the application of this technology and seek more ideal approaches to minimize difficulties related to stem cells.

Peripheral Blood Stem Cell Therapy Does Not Improve Outcomes of Femoral Head Osteonecrosis With Cap-Shaped Separated Cartilage Defect

A combination treatment with porous tantalum rod implantation and intra-arterial infusion of peripheral blood stem cells (PBSCs) provides a promise for treating early and intermediate stages of osteonecrosis of the femoral head (ONFH). However, its clinical indications and application restrictions remain unclear. This study aims to determine the clinical, histological, and radiological outcomes of a combination treatment using mechanical support and a targeted intra-arterial infusion of PBSCs for painful ONFH with a cap-shaped separation (CSS) cartilage defect. Compared with the standard pain management (control group), this combination treatment did not improve the Harris Hip Score (HHS) at 36 months. Micro-CT and histologic analyses showed severe focal destruction in all CSS-ONFH femoral heads in both the combination and control groups. Femoral heads showed a higher percentage of bone lesions in the combination treatment group than in the control group. There was no significant difference in osteoclast number in the subchondral bone areas between the two groups. A high level of expression of inflammatory cytokines, including tumor necrosis factor-α and interleukin-1β, was detected in blood vessels around the subchondral bone in both groups. The RANKL/OPG (receptor activator of the nuclear factor-kB ligand/osteoprotegerin) ratio was also similar between the control and combination treatment groups. Our results indicate that this combination treatment is not an effective method for the treatment of patients with painful CSS-ONFH. Moreover, this combination treatment did not inhibit inflammatory osteoclastogenesis in patients with more advanced disease. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:269-276, 2020.

MicroRNA‑186‑5p mediates osteoblastic differentiation and cell viability by targeting CXCL13 in non‑traumatic osteonecrosis

MicroRNAs (miRs) serve varying and important roles in the pathogenesis of non‑traumatic osteonecrosis (ON). However, the role miR‑186‑5p serves in the pathogenesis of osteonecrosis remains unknown and the clinical outcome of ON is still uncertain. The aim of the present study was to determine the expression characteristics, biological function and molecular mechanisms of miR‑186‑5p, which is associated with cancer development and progression, in osteoblastic differentiation and cell viability. The results of the present study showed that the expression levels of miR‑186‑5p were significantly higher in clinical non‑traumatic ON compared with osteoarthritis samples (P=0.0001). An inverse association was observed between miR‑186‑5p and CXCL13 expression levels. Furthermore, miR‑186‑5p inhibited phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT) signaling, downregulated osteoblast‑specific markers and reduced the viability and differentiation of human mesenchymal stem cells from bone marrow (HMSC‑bm) through targeting CXCL13. Increasing expression of CXCL13 in HMSC‑bm cells partially restored miR‑186‑5p‑mediated inhibition. In conclusion, abrogation of PI3K/AKT signaling triggered by miR‑186‑5p/CXCL13 may contribute to ON pathogenesis. These results highlight the possible clinical value of miR‑186‑5p in treatment for non‑traumatic ON.

Cell Therapy: Effect of Locally Injected Mesenchymal Stromal Cells Derived from Bone Marrow or Adipose Tissue on Bone Regeneration of Rat Calvarial Defects

Treatment of large bone defects is a challenging clinical situation that may be benefited from cell therapies based on regenerative medicine. This study was conducted to evaluate the effect of local injection of bone marrow-derived mesenchymal stromal cells (BM-MSCs) or adipose tissue-derived MSCs (AT-MSCs) on the regeneration of rat calvarial defects. BM-MSCs and AT-MSCs were characterized based on their expression of specific surface markers; cell viability was evaluated after injection with a 21-G needle. Defects measuring 5 mm that were created in rat calvaria were injected with BM-MSCs, AT-MSCs, or vehicle-phosphate-buffered saline (Control) 2 weeks post-defect creation. Cells were tracked by bioluminescence, and 4 weeks post-injection, the newly formed bone was evaluated by µCT, histology, nanoindentation, and gene expression of bone markers. BM-MSCs and AT-MSCs exhibited the characteristics of MSCs and maintained their viability after passing through the 21-G needle. Injection of both BM-MSCs and AT-MSCs resulted in increased bone formation compared to that in Control and with similar mechanical properties as those of native bone. The expression of genes associated with bone formation was higher in the newly formed bone induced by BM-MSCs, whereas the expression of genes involved in bone resorption was higher in the AT-MSC group. Cell therapy based on local injection of BM-MSCs or AT-MSCs is effective in delivering cells that induced a significant improvement in bone healing. Despite differences observed in molecular cues between BM-MSCs and AT-MSCs, both cells had the ability to induce bone tissue formation at comparable amounts and properties. These results may drive new cell therapy approaches toward complete bone regeneration.

Bone marrow mesenchymal stem cells: Aging and tissue engineering applications to enhance bone healing

Bone has well documented natural healing capacity that normally is sufficient to repair fractures and other common injuries. However, the properties of bone change throughout life, and aging is accompanied by increased incidence of bone diseases and compromised fracture healing capacity, which necessitate effective therapies capable of enhancing bone regeneration. The therapeutic potential of adult mesenchymal stem cells (MSCs) for bone repair has been long proposed and examined. Actions of MSCs may include direct differentiation to become bone cells, attraction and recruitment of other cells, or creation of a regenerative environment via production of trophic growth factors. With systemic aging, MSCs also undergo functional decline, which has been well investigated in a number of recent studies. In this review, we first describe the changes in MSCs during aging and discuss how these alterations can affect bone regeneration. We next review current research findings on bone tissue engineering, which is considered a promising and viable therapeutic solution for structural and functional restoration of bone. In particular, the importance of MSCs and bioscaffolds is highlighted. Finally, potential approaches for the prevention of MSC aging and the rejuvenation of aged MSC are discussed.

Stem cell therapy for treating osteonecrosis of the femoral head: From clinical applications to related basic research

Osteonecrosis of the femoral head (ONFH) is a refractory disease that is associated with collapse of the femoral head, with a risk of hip arthroplasty in younger populations. Thus, there has been an increased focus on early interventions for ONFH that aim to preserve the native articulation. Stem cell therapy is a promising treatment, and an increasing number of recent studies have focused on this topic. Many clinical studies have reported positive outcomes of stem cell therapy for the treatment of ONFH. To improve the therapeutic effects of this approach, many related basic research studies have also been performed. However, some issues must be further explored, such as the appropriate patient selection procedure, the optimal stem cell selection protocol, the ideal injection number, and the safety of stem cell therapy. The purpose of this review is to summarize the available clinical studies and basic research related to stem cell therapy for ONFH.

The role of cell therapies and hip arthroscopy in the management of osteonecrosis: an update

The exact pathophysiology of osteonecrosis of the femoral head (ONFH) is still unknown. There is evidence to suggest that in ON there is decreased population and altered function of the mesenchymal stem cells (MSCs) of the femoral head. This could influence both the actual occurrence of ON itself and the repair process that follows. Hence, in such an environment it only is rational to consider the use of cell-based treatments to potentially regenerate lost or damaged bone. The aim of this review is to provide an up-to-date, evidence-based information in the use of cell therapies in the treatment of nontraumatic ONFH and the use of hip arthroscopy in the field.

Early-stage osteonecrosis of the femoral head: where are we and where are we going in year 2018?

Osteonecrosis of the femoral head (ONFH) is a devastating condition affecting relatively young patients whereby the femoral head is necrotic, resulting in significant pain, articular surface collapse, and eventual osteoarthritis. This condition has been highly associated with chronic steroid use, alcoholism, and hip trauma, as well as other less common conditions. Without intervention, this condition has a high likelihood of progressing and developing into end-stage osteoarthritis. Unfortunately, ONFH is difficult to diagnose on plain radiographs in the early stages of the disease, and often requires more advanced imaging modalities such as MRI in order to fully assess for early degeneration. Providers, therefore, must have a high index of suspicion when a younger patient presents with hip pain and negative X-rays. Unfortunately, in patients whose femoral heads have already collapsed, joint-preserving procedures are not effective, and total hip arthroplasty remains the most reliable long-term treatment. Multiple treatments have been pursued to address osteonecrosis in patients whose femoral head have not yet collapsed, but the results of these treatments are mixed. The most promising of these interventions to date is core decompression with the use of concentrated bone marrow aspirate to improve the healing potential of the femoral head. Further studies including randomized clinical trials are necessary in order to assess the effectiveness of this therapy, the best possible source of cells and the best method of implantation in order to further improve results in those with pre-collapse ONFH.

Prevention of glucocorticoid-associated osteonecrosis by intravenous administration of mesenchymal stem cells in a rabbit model

Background

Glucocorticoid-associated osteonecrosis is an intractable condition, making the establishment of preventative strategies of particular importance. Recently various studies using mesenchymal stem cells (MSC) have been conducted. Using a rabbit glucocorticoid-associated osteonecrosis model we administered green fluorescent protein (GFP)-labeled MSC intravenously to investigate their effect on osteonecrosis.

Methods

A rabbit osteonecrosis model in which methylprednisolone (MP) 20 mg/kg was injected into the gluteus of a Japanese white rabbit was used. Simultaneously with MP, MSC labeled with GFP (GFP-labeled MSC) were injected intravenously. Fourteen days later the animals were killed (MSC(+)/MP(+)/14d), femurs were extracted, and the prevalence of osteonecrosis was determined histopathologically. Also, animals were killed 3 days after simultaneous administration of GFP-labeled MSC and MP (MSC(+)/MP(+)/3d), and western blotting (WB) for GFP was performed of the femur, liver, kidney, lung, blood vessel, and vertebra, in addition to immunohistochemical study of femur. As a control for the histopathological study, animals were killed 14 days after MP administration and intravenous vehicle injection (MSC(−)/MP(+)/14d). For WB, animals were killed 3 days after intravenous GFP-labeled MSC administration and vehicle injection into the gluteus (MSC(+)/MP(−)/3d).

Results

In MSC(−)/MP(+)/14d osteonecrosis was found in 7 of 10 rabbits (70%), while in MSC(+)/MP(+)/14d, partial bone marrow necrosis was found in only 1 rabbit (12.5%); osteonecrosis was not found in 7 of 8 rabbits (p < 0.05). WB showed expression of GFP in the femur, not in the liver, kidney, lung, blood vessel, or vertebra, of MSC(+)/MP(+)/3d; expression of GFP-labeled MSC was absent in the femur of MSC(+)/MP(−)/3d. In the immunohistochemical study of MSC(+)/MP(+)/3d, homing of GFP-labeled MSC was noted perivascularly in the femur, but not in MSC(+)/MP(−)/3d.

Conclusions

With transvenous MSC administration a significant prophylactic effect against glucocorticoid-associated osteonecrosis was found. Direct administration of MSC to the site of tissue injury requires highly invasive surgery. In contrast, as shown here the simple and hardly invasive intravenous administration of MSC may succeed in preventing osteonecrosis.

Electronic supplementary material

The online version of this article (10.1186/s12891-017-1837-1) contains supplementary material, which is available to authorized users.

Autologous Stem Cells Combined Core Decompression for Treatment of Avascular Necrosis of the Femoral Head: A Systematic Meta-Analysis

OBJECTIVE

This study aims to systematically evaluate the efficacy and safety of core decompression combined transplantation of autologous bone marrow stem cells (CDBMSCs) for treatment of avascular necrosis of the femoral head (ANFH).

METHODS

Randomized controlled trials (RCTs) regarding effectiveness of core decompression combined transplantation of autologous bone marrow stem cells for treating ANFH were searched in 8 comprehensive databases prior to September 2016. The data analysis was performed by using the RevMan version 5.3.

RESULTS

A total of 11 studies with 507 participants were included. Results showed that CDBMSCs group was more effective than CD group in increasing Harris hip score, decreasing necrotic area of femoral head, collapse of femoral head, and conversion to total hip replacement incidence. In the subgroup analysis, the results did not change in different intervention measure substantially. In addition, the safety of CDBMSCs for ANFH is reliable.

CONCLUSION

Based on the systematic review, our findings suggest that core decompression combined transplantation of autologous bone marrow stem cells appeared to be more efficacious in the treatment at early stages of ANFH.

Core decompression and biotechnologies in the treatment of avascular necrosis of the femoral head

Avascular necrosis (AVN) of the femoral head (FH) causes 5% to 12% of total hip arthroplasties (THA). It especially affects active male adults between the third and fifth decades of life. The exact worldwide incidence is unknown. There are only few data related to each country, but most of it relates to the United States.Non-surgical management has a very limited role in the treatment of AVN of the FH and only in its earliest stages. Core decompression (CD) of the hip is the most common procedure used to treat the early stages of AVN of the FH. Recently, surgeons have considered combining CD with autologous bone-marrow cells, demineralised bone matrix or bone morphogenetic proteins or methods of angiogenic potential to enhance bone repair in the FH.Manuscripts were deemed eligible for our review if they evaluated treatment of early stage AVN of the FH with biotechnology implanted via CD. After application of eligibility criteria, we selected 19 reports for final analysis.The principal results showed that only by correctly mastering the therapeutic principles and adopting proper methods specifically oriented to different stages can the best therapeutic effect be achieved. Combining CD with biotechnology could result in a novel long-lasting hip- preserving treatment option.Furthermore, more refined clinical studies are needed to establish the effectiveness of biotechnology treatments in AVN of the FH. Cite this article: EFORT Open Rev 2017;2:41-50. DOI: 10.1302/2058-5241.2.150006.

Exosomes Secreted from Human-Induced Pluripotent Stem Cell-Derived Mesenchymal Stem Cells Prevent Osteonecrosis of the Femoral Head by Promoting Angiogenesis

Background: Local ischemia is the main pathological performance in osteonecrosis of the femoral head (ONFH). There is currently no effective therapy to promote angiogenesis in the femoral head. Recent studies revealed that exosomes secreted by induced pluripotent stem cell-derived mesenchymal stem cells (iPS-MSC-Exos) have great therapeutic potential in ischemic tissues, but whether they could promote angiogenesis in ONFH has not been reported, and little is known regarding the underlying mechanism.

Methods: iPS-MSC-Exos were intravenously injected to a steroid-induced rat osteonecrosis model. Samples of the femoral head were obtained 3 weeks after all the injections. The effects were assessed by measuring local angiogenesis and bone loss through histological and immunohistochemical (IHC) staining, micro-CT and three-dimensional microangiography. The effects of exosomes on endothelial cells were studied through evaluations of proliferation, migration and tube-forming analyses. The expression levels of angiogenic related PI3K/Akt signaling pathway of endothelial cells were evaluated following stimulation of iPS-MSC-Exos. The promoting effects of exosomes were re-evaluated following blockade of PI3K/Akt.

Results: The in vivo study revealed that administration of iPS-MSC-Exos significantly prevented bone loss, and increased microvessel density in the femoral head compared with control group. We found that iPS-MSC-Exos significantly enhanced the proliferation, migration and tube-forming capacities of endothelial cells in vitro. iPS-MSC-Exos could activate PI3K/Akt signaling pathway in endothelial cells. Moreover, the promoting effects of iPS-MSC-Exos were abolished after blockade of PI3K/Akt on endothelial cells.

Conclusions: Our findings suggest that transplantation of iPS-MSC-Exos exerts a preventative effect on ONFH by promoting local angiogenesis and preventing bone loss. The promoting effect might be attributed to activation of the PI3K/Akt signaling pathway on endothelial cells. The data provide the first evidence for the potential of iPS-MSC-Exos in treating ONFH.

Fate of bone marrow mesenchymal stromal cells following autologous transplantation in a rabbit model of osteonecrosis

BACKGROUND AIMS

Internalizing quantum dots (i-QDs) are a useful tool for tracking cells in vivo in models of tissue regeneration. We previously synthesized i-QDs by conjugating QDs with a unique internalizing antibody against a heat shock protein 70 family stress chaperone. In the present study, i-QDs were used to label rabbit mesenchymal stromal cells (MSCs) that were then transplanted into rabbits to assess differentiation potential in an osteonecrosis model.

METHODS

The i-QDs were taken up by bone marrow-derived MSCs collected from the iliac of 12-week-old Japanese white rabbits that were positive for cluster of differentiation (CD)81 and negative for CD34 and human leukocyte antigen DR. The average rate of i-QD internalization was 93.3%. At 4, 8, 12, and 24 weeks after transplantation, tissue repair was evaluated histologically and by epifluorescence and electron microscopy.

RESULTS

The i-QDs were detected at the margins of the drill holes and in the necrotized bone trabecular. There was significant colocalization of the i-QD signal in transplanted cells and markers of osteoblast and mineralization at 4, 8, and 12 weeks post-transplantation, while i-QDs were detected in areas of mineralization at 12 and 24 weeks post-transplantation. Moreover, i-QDs were observed in osteoblasts in regenerated tissue by electron microscopy, demonstrating that the tissue was derived from transplanted cells.

CONCLUSION

These results indicate that transplanted MSCs can differentiate into osteoblasts and induce tissue repair in an osteonecrosis model and can be tracked over the long term by i-QD labeling.

Long-Term Tracking of the Osteogenic Differentiation of Mouse BMSCs by Aggregation-Induced Emission Nanoparticles

Bone marrow-derived mesenchymal stem cells (BMSCs) have shown great potential for bone repair due to their strong proliferation ability and osteogenic capacity. To evaluate and improve the stem cell-based therapy, long-term tracking of stem cell differentiation into bone-forming osteoblasts is required. However, conventional fluorescent trackers such as fluorescent proteins, quantum dots, and fluorophores with aggregation-caused quenching (ACQ) characteristics have intrinsic limitations of possible interference with stem cell differentiation, heavy metal cytotoxicity, and self-quenching at a high labeling intensity. Herein, we developed aggregation-induced emission nanoparticles decorated with the Tat peptide (AIE-Tat NPs) for long-term tracking of the osteogenic differentiation of mouse BMSCs without interference of cell viability and differentiation ability. Compared with the ability of the commercial Qtracker 655 for tracking of only 6 passages of mouse BMSCs, AIE-Tat NPs have shown a much superior performance in long-term tracking for over 12 passages. Moreover, long-term tracking of the osteogenic differentiation process of mouse BMSCs was successfully conducted on the biocompatible hydroxyapatite scaffold, which is widely used in bone tissue engineering. Thus, AIE-Tat NPs have promising applications in tracking stem cell fate for bone repair.

Stem Cell Therapy for the Treatment of Hip Osteonecrosis: A 30-Year Review of Progress

Avascular necrosis of the femoral head is caused by a multitude of etiologic factors and is associated with collapse with a risk of hip arthroplasty in younger populations. A focus on early disease management with the use of stem cells was proposed as early as 1985 by the senior author (PH). We undertook a systematic review of the medical literature to examine the progress in cell therapy during the last 30 years for the treatment of early stage osteonecrosis.

Clinical outcomes of osteonecrosis of the femoral head after autologous bone marrow stem cell implantation: a meta-analysis of seven case-control studies

The purpose of this study was to evaluate the clinical outcomes of osteonecrosis of the femoral head after autologous bone marrow stem cell implantation. We searched the PubMed, Embase and Web of Science databases and included all case-control trials that reported on the clinical outcomes of osteonecrosis progression, incidence of total hip arthroplasty and improvement in Harris hip scores. Overall, seven case-control trials were included. Compared with the controls, patients treated with the bone marrow stem cells implantation treatment showed improved clinical outcomes with delayed osteonecrosis progression (odds ratio = 0.17, 95% CI: 0.09 - 0.32; p <0.001), a lower total hip arthroplasty incidence (odds ratio = 0.30, 95% CI: 0.12 - 0.72; p <0.01) and increased Harris hip scores (mean difference = 4.76, 95% CI: 1.24 - 8.28; p<0.01). The heterogeneity, publication bias, and sensitivity analyses showed no statistical difference significant differences between studies. Thus, our study suggests that autologous bone marrow stem cells implantation has a good therapeutic effect on osteonecrosis of the femoral, resulting in beneficial clinical outcomes. However, trials with larger sample sizes are needed to confirm these findings.

The role of "cell therapy" in osteonecrosis of the femoral head. A systematic review of the literature and meta-analysis of 7 studies

BACKGROUND AND PURPOSE

The value of core decrompression for treatment of osteonecrosis of the femoral head (ONFH) is unclear. We investigated by a literature review whether implantation of autologous bone marrow aspirate, containing high concentrations of pluripotent mesenchymal stem cells, into the core decompression track would improve the clinical and radiological results compared with the classical method of core decompression alone. The primary outcomes of interest were structural failure (collapse) of the femoral head and conversion to total hip replacement (THR).

PATIENTS AND METHODS

All randomized and non-randomized control trials comparing simple core decompression with autologous bone marrow cell implantation into the femoral head for the treatment of ONFH were considered eligible for inclusion. The methodological quality of the studies included was assessed independently by 2 reviewers using the Cochrane Collaboration tool for assessing risk of bias in randomized studies. Of 496 relevant citations identified, 7 studies formed the basis of this review.

RESULTS

The pooled estimate of effect size for structural failure of the femoral head favored the cell therapy group, as, in this treatment group, the odds of progression of the femoral head to the collapse stage were reduced by a factor of 5 compared to the CD group (odds ratio (OR) = 0.2, 95% CI: 0.08-0.6; p = 0.02). The respective summarized estimate of effect size yielded halved odds for conversion to THR in the cell therapy group compared to CD group (OR = 0.6, 95% CI: 0.3-1.02; p = 0.06).

INTERPRETATION

Our findings suggest that implantation of autologous mesenchymal stem cells (MSCs) into the core decompression track, particularly when employed at early (pre-collapse) stages of ONFH, would improve the survivorship of femoral heads and reduce the need for hip arthroplasty.

The Fate and Distribution of Autologous Bone Marrow Mesenchymal Stem Cells with Intra-Arterial Infusion in Osteonecrosis of the Femoral Head in Dogs

This study aimed to investigate if autologous bone marrow mesenchymal stem cells (MSCs) could treat osteonecrosis of the femoral head (ONFH) and what the fate and distribution of the cells are in dogs. Twelve Beagle dogs were randomly divided into two groups: MSCs group and SHAM operated group. After three weeks, dogs in MSCs group and SHAM operated group were intra-arterially injected with autologous MSCs and 0.9% normal saline, respectively. Eight weeks after treatment, the necrotic volume of the femoral heads was significantly reduced in MSCs group. Moreover, the trabecular bone volume was increased and the empty lacunae rate was decreased in MSCs group. In addition, the BrdU-positive MSCs were unevenly distributed in femoral heads and various vital organs. But no obvious abnormalities were observed. Furthermore, most of BrdU-positive MSCs in necrotic region expressed osteocalcin in MSCs group and a few expressed peroxisome proliferator-activated receptor-γ (PPAR-γ). Taken together, these data indicated that intra-arterially infused MSCs could migrate into the necrotic field of femoral heads and differentiate into osteoblasts, thus improving the necrosis of femoral heads. It suggests that intra-arterial infusion of autologous MSCs might be a feasible and relatively safe method for the treatment of femoral head necrosis.