Factors Influencing the Yield of Progenitor Cells in Bone Marrow Aspiration Concentrate-A Retrospective Analysis of 58 Patients

Optimizing bone marrow harvesting sites for enhanced mesenchymal stem cell yield and efficacy in knee osteoarthritis treatment

Knee osteoarthritis (OA) is a debilitating condition with limited long-term treatment options. The therapeutic potential of mesenchymal stem cells (MSCs), particularly those derived from bone marrow aspirate concentrate, has garnered attention for cartilage repair in OA. While the iliac crest is the traditional site for bone marrow harvesting (BMH), associated morbidity has prompted the exploration of alternative sites such as the proximal tibia, distal femur, and proximal humerus. This paper reviews the impact of different harvesting sites on mesenchymal stem cell (MSC) yield, viability, and regenerative potential, emphasizing their relevance in knee OA treatment. The iliac crest consistently offers the highest MSC yield, but alternative sites within the surgical field of knee procedures offer comparable MSC characteristics with reduced morbidity. The integration of harvesting techniques into existing knee surgeries, such as total knee arthroplasty, provides a less invasive approach while maintaining therapeutic efficacy. However, variability in MSC yield from these alternative sites underscores the need for further research to standardize techniques and optimize clinical outcomes. Future directions include large-scale comparative studies, advanced characterization of MSCs, and the development of personalized harvesting strategies. Ultimately, the findings suggest that optimizing the site of BMH can significantly influence the quality of MSC-based therapies for knee OA, enhancing their clinical utility and patient outcomes.

Bone marrow aspirate concentrate (BMAC) harvested in the axial and appendicular skeleton does not differ in progenitor cell count: A systematic review and meta-analysis

Introduction

Bone marrow aspirate concentrate (BMAC) is a reliable source of progenitor cells that facilitate healing, and it is typically harvested from the iliac crest. The purpose of this systematic review and meta-analysis was to compare total nucleated cell (TNC) count and the presence of colony-forming units (CFUs) in BMAC harvested from axial versus appendicular harvest sites.

Methods

In accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, PubMed, Embase, and Cochrane Library databases were searched in August 2024 for studies published after 2004. Studies were included if they evaluated cell counts within BMAC samples harvested from males and females of any age and were prospective. Studies that had no reported cell count within BMAC samples, had evaluations of biologic material other than BMAC, or were translational or cadaveric studies, as well as review articles or technical notes, were excluded. Patients were divided into two cohorts based on whether BMAC was harvested from their axial or appendicular skeleton.

Results

The initial search identified 2126 studies, of which 15 non-randomized prospective studies with a total of 583 patients were included. Each study had low risk of bias. In the axial skeleton, TNC counts ranged from 0.1-502 × 106 cells/mL, and CFU concentration ranged from 0 to 807 CFU/mL. In the appendicular skeleton, TNC counts ranged from 0.1-87 × 106 cells/mL and CFU counts ranged from 0 to 802.7 CFU/mL. No significant differences in TNC or CFU count in BMAC harvested from the axial versus appendicular skeleton were observed.

Conclusions

BMAC harvested from the axial and appendicular skeletons demonstrate significant variability in progenitor cell concentration. These findings suggest that harvesting at appendicular sites near the operative location allows the surgeon to extract sufficient quality BMAC as compared to harvest sites within the axial skeleton, such as the iliac crest.

Level of evidence

Level II, systematic review of level II studies.

"Cellularity as a predictive tool for mesenchymal stem cell concentration in bone marrow concentrates: Implications for regenerative medicine"

Background

Mesenchymal stem cells (MSCs) derived from bone marrow play an increasingly important role in regenerative medicine due to their capacity to promote tissue regeneration in various clinical contexts. Applications include the treatment of osteoarthritis, bone regeneration post-injury, and the management of conditions such as Crohn's disease, alopecia, and nervous system reconstruction. Accurate quantification of MSCs within Bone Marrow Concentrates (BMCs) is essential for ensuring the quality and efficacy of these cell therapy products in clinical settings.

Objective

This study aims to quantify the population of CD271+ and CD45- cells in BMCs prepared using the method we have selected and to provide a basis for comparing these results with other BMC products. Additionally, we seek to determine whether the total cell count in BMCs can serve as a reliable indicator of MSC numbers and if cellularity (the number of cells per ml) can predict a higher percentage of MSCs within the population.

Methods

Bone Marrow Aspirates (BMA) were collected from 41 patients undergoing knee or hip arthroplasty. Aspirates were processed using density gradient centrifugation and positive selection of CD271+ cells. Flow cytometry was applied to analyze cell subsets, and cell counts were determined with a NucleoCounter. The relationships between BMA cellularity (total cells per ml), MSC concentration (MSC count per ml), and MSC percentage (the proportion of MSCs within the total cell population) were assessed.

Results

The mean percentage of CD271+ CD45- cells in bone marrow samples was 0.03 % (SD 0.03 %). Cellularity varied significantly among samples, with a mean of 6 million cells/ml (SD 8.7 million cells/ml). A strong correlation was observed between BMC cellularity and MSC concentration (p < 0.05), although no correlation was found between cellularity and the MSC percentage.

Conclusion

Despite high variability in cellularity, the concentration of MSCs correlated strongly with BMC cellularity, suggesting that total cell counts can be used to estimate MSC numbers in BMCs. However, cellularity is not an indicator of a particularly high MSC content. This study supports the use of cell counts as a measure for estimating MSC concentration in BMCs. Future research should focus on establishing direct comparisons with other BMC products and exploring factors influencing cellularity and MSC percentages to enhance BMC quality for clinical applications.

Obese Patients Do Not Benefit from Bone Marrow Aspiration Concentrate Injection for Knee Osteoarthritis: A Prospective Cohort Study of 68 Patients

BACKGROUND

Bone marrow aspirate concentrate (BMAC) is considered one of the biological treatments for knee osteoarthritis (KOA). Patient selection remains a key factor to ensure that optimal treatment benefit and body mass index (BMI) are one of the key factors to be considered. This study aims to evaluate the influence of obesity on the duration of treatment benefit of BMAC for KOA.

METHODS

This prospective cohort study enrolled 68 patients who underwent a single BMAC injection for early stage KOA. The patients were categorized based on their BMI into normal, overweight, and obese groups. Visual Analog Scale (VAS) for pain and Knee Injury and Osteoarthritis Outcome Score (KOOS) were the outcomes analysed. The duration of treatment benefit is estimated by Kaplan-Meier survival analysis.

RESULTS

Sixty-eight patients (normal BMI = 43, overweight BMI = 15, obese BMI = 10) were enrolled in the study for analysis. While significant improvement in the outcome scores was noted compared to the baseline throughout the study period in the normal BMI and overweight group, the obese group returned to baseline parameters at 3 months follow-up. Patients in the normal BMI group demonstrated significant improvement in VAS (p < 0.001) and KOOS (p < 0.001) outcomes compared to the overweight and obese group. Survival analysis demonstrated a significant decline in the mean treatment benefit of 9.8 (95%CI [6.151-13.431], p = 0.027) months in normal BMI group to 6.6 (95%CI [3.473-9.727]) months and 4.1 (95%CI [2.760-5.440]) months in overweight and obese groups, respectively.

CONCLUSION

BMI is a significant factor that influences the benefit of BMAC injection for early knee OA. Hence, BMAC injection must be used with caution in individuals with high BMI.

Innovative Approaches in Knee Osteoarthritis Treatment: A Comprehensive Review of Bone Marrow-Derived Products

Knee osteoarthritis (OA) is a chronic articular disease characterized by the progressive degeneration of cartilage and bone tissue, leading to the appearance of subchondral cysts, osteophyte formation, and synovial inflammation. Conventional treatments consist of non-steroidal anti-inflammatory drugs (NSAIDs), analgesics, and glucocorticoids. However, the prolonged use of these drugs causes adverse effects. NSAIDs, for instance, are known to be nephrotoxic, increasing the damage to articular cartilage. New therapies capable of accelerating the process of tissue regeneration and repair are being discussed, such as the use of orthobiologics that are naturally found in the body and obtained through minimally invasive collection and/or laboratory manipulations. Bone marrow aspirate (BMA) and bone marrow aspirate concentrate (BMAC) are both rich in hematopoietic stem cells, mesenchymal stem cells (MSCs), and growth factors (GFs) that can be used in the healing process due to their anabolic and anti-inflammatory effects. The aim of this literature review is to assess the efficacy of BMA and BMAC in the treatment of knee OA based on the favorable results that researchers have obtained with the use of both orthobiologics envisaging an accelerated healing process and the prevention of OA progression.

Evolution and Innovations in Bone Marrow Cellular Therapy for Musculoskeletal Disorders: Tracing the Historical Trajectory and Contemporary Advances

Bone marrow cellular therapy has undergone a remarkable evolution, significantly impacting the treatment of musculoskeletal disorders. This review traces the historical trajectory from early mythological references to contemporary scientific advancements. The groundbreaking work of Friedenstein in 1968, identifying fibroblast colony-forming cells in bone marrow, laid the foundation for future studies. Caplan's subsequent identification of mesenchymal stem cells (MSCs) in 1991 highlighted their differentiation potential and immunomodulatory properties, establishing them as key players in regenerative medicine. Contemporary research has focused on refining techniques for isolating and applying bone marrow-derived MSCs. These cells have shown promise in treating conditions like osteonecrosis, osteoarthritis, and tendon injuries thanks to their ability to promote tissue repair, modulate immune responses, and enhance angiogenesis. Clinical studies have demonstrated significant improvements in pain relief, functional recovery, and tissue regeneration. Innovations such as the ACH classification system and advancements in bone marrow aspiration methods have standardized practices, improving the consistency and efficacy of these therapies. Recent clinical trials have validated the therapeutic potential of bone marrow-derived products, highlighting their advantages in both surgical and non-surgical applications. Studies have shown that MSCs can reduce inflammation, support bone healing, and enhance cartilage repair. However, challenges remain, including the need for rigorous characterization of cell populations and standardized reporting in clinical trials. Addressing these issues is crucial for advancing the field and ensuring the reliable application of these therapies. Looking ahead, future research should focus on integrating bone marrow-derived products with other regenerative techniques and exploring non-surgical interventions. The continued innovation and refinement of these therapies hold promise for revolutionizing the treatment of musculoskeletal disorders, offering improved patient outcomes, and advancing the boundaries of medical science.

Effect of Cellular Dosage of Bone Marrow Aspiration Concentrate on the Radiological Outcomes in Knee Osteoarthritis: A Phase I Dose-Escalation Study

INTRODUCTION

Knee osteoarthritis(KOA), a chronic degenerative disease, significantly impairs quality of life due to pain and mobility limitations. Traditional treatments focus on symptom management without addressing the underlying disease progression, leading to a growing interest in regenerative medicine approaches. Bone marrow aspirate concentrate (BMAC), rich in mesenchymal stem cells and growth factors, has shown potential for cartilage repair and symptom relief in KOA. Despite promising outcomes, the optimal BMAC dosage for knee OA treatment remains undetermined. This study aims to evaluate the radiological outcomes of varying BMAC dosages in knee OA treatment.

METHODS

This prospective controlled dose-escalation study involved 75 patients with early-stage knee OA, categorized into three groups based on BMAC dosage administered 10x106 cells (low-dose group), 50 × 106 cells (medium-dose group), or 100x106 cells (high-dose group). All the patients underwent a single intra-articular injection of BMAC and were monitored over a year. The primary outcomes include magnetic resonance observation of cartilage repair tissue (MOCART 2.0) score to assess the cartilage.

RESULTS

We noted significant improvement in the overall MOCART score (p = 0.027) and subchondral change sub-score (p = 0.048) and defect filling sub-score (p = 0.025) in the medium- and high-dose cohorts compared to the low-dose cohort at 1 year follow-up. Although we noted positive correlation between the clinical and radiological outcome (r = 0.43), we did not find any significant different in the clinical outcome between the treatment groups.

CONCLUSION

BMAC for OA knee resulted in significant improvement in the radiological scores compared to the baseline. Medium and high doses of BMAC result in significantly higher radiological scores compared to low-dose BMAC at 1 year. However, the radiological improvement did not translate into functional improvement, irrespective of the dosage administered at 1 year. Further research is necessary on the long-term outcomes to understand and optimize the dosing strategy based on clinico-radiological results.

Increased Cellular Dosage of Bone Marrow Aspiration Concentrate Does Not Translate to Increased Clinical Effectiveness in Knee Osteoarthritis: A Phase I Dose Escalation Study

INTRODUCTION

Knee osteoarthritis (KOA), a chronic degenerative disease, significantly impairs quality of life due to pain and mobility limitations. Traditional treatments focus on symptom management without addressing the underlying disease progression, leading to a growing interest in regenerative medicine approaches. Bone marrow aspirate concentrate (BMAC), rich in mesenchymal stem cells and growth factors, has shown potential for cartilage repair and symptom relief in KOA. Despite promising outcomes, the optimal BMAC dosage for knee OA treatment remains undetermined. This study aims to evaluate the clinical efficacy and safety of varying BMAC dosages in knee OA treatment.

METHODS

This prospective controlled dose-escalation study involved 75 patients with early-stage knee OA, categorized into three groups based on BMAC dosage administered 10 × 106 cells (low-dose group), 50 × 106 cells (medium-dose group), or 100 × 106 cells (high-dose group). All the patients underwent a single intra-articular injection of BMAC and were monitored over a year. The primary outcomes include Visual Analog Scale (VAS) for pain and the Knee Injury and Osteoarthritis Outcome Score (KOOS) for joint function recorded at baseline, 1, 3, 6, and 12 months post-intervention. Adverse events were also documented.

RESULTS

Significant clinical improvements in VAS and KOOS scores were noted across all groups at all time points compared to the baseline. However, these improvements did not significantly differ between dosage groups throughout the follow-up period. Adverse effects were minimal and primarily consisted of transient post-injection pain and effusion, with no dose-dependent increase in complications.

CONCLUSION

BMAC treatment for knee OA is safe and demonstrates potential for significant pain relief and functional improvement, irrespective of the dosage administered within the tested range. The lack of significant differences among varying dosages suggests a plateau in therapeutic efficacy beyond a certain threshold. Further research is necessary on the long-term outcomes to optimize the dosing strategy.

Bone Marrow Aspirate Concentrate for Treatment of Primary Knee Osteoarthritis: A Prospective, Single-Center, Non-randomized Study with 2-Year Follow-Up

INTRODUCTION

Knee osteoarthritis (OA) is a widespread, disabling condition with no intervention to fully restore cartilage or halt progression. Bone marrow aspirate concentrate (BMAC), an autologous product from bone marrow aspiration, has shown promise as a regenerative therapy due to its cell composition and chondrogenic effects. Our study aims to assess the functional outcomes, including pain, function, satisfaction, and complications post-BMAC injection in knee OA patients.

MATERIALS AND METHODS

In this prospective, single-center study, 63 patients with grade II-III knee OA (Kellgren-Lawrence (K-L) scale) unresponsive to conservative management underwent BMAC injection. The procedure involved bone marrow aspiration from the anterior iliac crest, processing to obtain a concentrate, followed by intra-articular injection. Patients were followed for 24 months, assessing outcomes using the Visual Analog Scale (VAS), International Knee Documentation Committee (IKDC) score, and MOCART 2.0 score.

RESULTS

The cohort, with a slight female predominance and predominantly aged 41-50 years, majorly comprised K-L grade III OA patients. BMAC treatment resulted in significant improvements in VAS pain scores, IKDC functional scores, and MOCART 2.0 scores over the 24-month follow-up.

CONCLUSION

BMAC injection provides significant improvement in both pain and functional outcomes at mid-term follow-up in patients with mild-to-moderate OA of the knee. Further high-quality, adequately powered, multi-center, prospective, double-blinded, randomized controlled trials with longer follow-up are necessary to justify the routine clinical use of BMAC for treatment of patients suffering with knee OA.

Exosomes for the Management of Low Back Pain: A Review of Current Clinical Evidence

Low back pain affects millions of people, creating an enormous financial burden on the global healthcare system. Traditional treatment modalities are short-lived and have shortcomings. Recently, orthobiologics, including extracellular vesicles or exosomes derived from mesenchymal stem cells, have markedly increased for managing musculoskeletal conditions. Here, the primary aim is to review the outcomes of clinical studies using extracellular vesicles or exosomes for treating low back pain. Numerous databases (Scopus, PubMed, Web of Science, Embase, and Google Scholar) were searched using terms for the intervention 'exosomes' and the treatment 'low back pain' for studies published in English to March 18, 2024. Articles utilizing exosomes for the management of low back pain were included. Articles not utilizing exosomes, not explicitly stating the presence of exosomes in their formulation, or not targeting low back pain were excluded. Two articles that met our pre-defined criteria were included in this review. The results showed that administering extracellular vesicles or exosomes is safe and potentially effective in patients suffering from low back pain. Yet, more sufficiently powered, multi-center, prospective, randomized, and non-randomized trials with longer follow-up are essential to assess the long-term safety and efficacy of extracellular vesicles or exosomes derived from various sources and to support its routine clinical use for managing low back pain.

Navigating the Therapeutic Landscape: A Comprehensive Review of Platelet-Rich Plasma and Bone Marrow Aspirate Concentrate in Knee Osteoarthritis

This comprehensive review provides an in-depth analysis of platelet-rich plasma (PRP) and bone marrow aspirate concentrate (BMAC) as potential treatments for knee osteoarthritis. It explores their mechanisms of action, clinical efficacy, safety considerations, and the importance of personalised treatment approaches. The review highlights promising findings regarding the ability of PRP and BMAC to alleviate symptoms, improve joint function, and potentially slow disease progression. It emphasises the need for further research into long-term outcomes, direct comparative studies, protocol standardisation, biomarker identification, and cost-effectiveness assessments to enhance clinical practice. While the review does not directly compare PRP and BMAC, it provides valuable insights into their respective roles in knee osteoarthritis management. The review aims to contribute to evidence-based advancements in regenerative therapies for knee osteoarthritis by addressing critical research priorities and refining treatment strategies.

Culture-expanded mesenchymal stromal cell therapy: does it work in knee osteoarthritis? A pathway to clinical success

Osteoarthritis (OA) is a degenerative multifactorial disease with concomitant structural, inflammatory, and metabolic changes that fluctuate in a temporal and patient-specific manner. This complexity has contributed to refractory responses to various treatments. MSCs have shown promise as multimodal therapeutics in mitigating OA symptoms and disease progression. Here, we evaluated 15 randomized controlled clinical trials (RCTs) and 11 nonrandomized RCTs using culture-expanded MSCs in the treatment of knee OA, and we found net positive effects of MSCs on mitigating pain and symptoms (improving function in 12/15 RCTs relative to baseline and in 11/15 RCTs relative to control groups at study endpoints) and on cartilage protection and/or repair (18/21 clinical studies). We examined MSC dose, tissue of origin, and autologous vs. allogeneic origins as well as patient clinical phenotype, endotype, age, sex and level of OA severity as key parameters in parsing MSC clinical effectiveness. The relatively small sample size of 610 patients limited the drawing of definitive conclusions. Nonetheless, we noted trends toward moderate to higher doses of MSCs in select OA patient clinical phenotypes mitigating pain and leading to structural improvements or cartilage preservation. Evidence from preclinical studies is supportive of MSC anti-inflammatory and immunomodulatory effects, but additional investigations on immunomodulatory, chondroprotective and other clinical mechanisms of action are needed. We hypothesize that MSC basal immunomodulatory "fitness" correlates with OA treatment efficacy, but this hypothesis needs to be validated in future studies. We conclude with a roadmap articulating the need to match an OA patient subset defined by molecular endotype and clinical phenotype with basally immunomodulatory "fit" or engineered-to-be-fit-for-OA MSCs in well-designed, data-intensive clinical trials to advance the field.