Human Lipoaspirate as Autologous Injectable Active Scaffold for One-Step Repair of Cartilage Defects

Role of micro‑fragmented adipose tissue in cartilage repair (Review)

Osteoarthritis (OA) is the most common degenerative joint disease, and one of the core factors in its development is articular cartilage damage. Due to the lack of vascular tissue in articular cartilage, if not treated in time, the damaged cartilage cannot regenerate spontaneously, thus leading to the occurrence of OA. Research has found that through a new type of fully enclosed device, lipogems®, micro-fragmented adipose tissue (MFAT) can be obtained by treating adipose tissue with mild mechanical force. MFAT does not require cell expansion, enzymatic treatment, or other major manipulations, and can maintain the complete stromal vascular niche. The present review discusses the latest research progress of the mechanism of MFAT in the repair of cartilage injury in OA, providing a new direction for the treatment of OA.

Micro-fragmented adipose tissue-An innovative therapeutic approach: A narrative review

Subcutaneous adipose tissue provides distinct advantages as a source of mesenchymal stem cells due to its accessibility and the ease of isolating stem cells. Human adipose stem cells, located in the stromal-vascular fraction, can be harvested using mechanical methods to produce microfragmented adipose tissue (MFAT). Local injections of MFAT have shown potential in promoting natural tissue regeneration. This review introduces the concept of MFAT, highlights its clinical applications, and explores its potential in regenerative medicine, offering insights into its role as an innovative therapeutic approach.

Microfragmented Adipose Tissue Associated With Collagen Membrane in the Treatment of Focal Knee Cartilage Defect

Focal articular cartilage defects are an important factor that leads to dysfunction of the knee joint. Several different surgical approaches have been tried, most of them showing poor results in the long term. The use of orthobiologics in the context of focal chondral lesion has emerged as a potential tool in the treatment of this condition. In this article, we present a surgical technique for the treatment of focal chondral lesions using a collagen membrane associated with microfragmented adipose tissue graft.

Does Secondary Mechanical Manipulation of Lipoaspirate Enhance the Vasculogenic Potential of Fat Grafts? A Systematic Review

BACKGROUND

Fat grafting is a highly versatile option in the reconstructive armamentarium but with unpredictable retention rates and outcomes. The primary outcome of this systematic review was to assess whether secondary mechanically processed lipoaspirate favorably enhances the vasculogenic potential of fat grafts when compared to unprocessed lipoaspirate or fat grafts prepared using centrifugation alone. The secondary outcome was to assess the evidence around graft retention and improved outcomes when comparing the aforementioned groups.

METHODS

A search on MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials was conducted up to February 2022. All human and animal research, which provided a cross-comparison between unprocessed, centrifuged, secondary mechanically fragmented (SMF) or secondary mechanically disrupted (SMD) fat grafts, was included.

RESULTS

Thirty-one full texts were included. Vasculogenic potential was assessed by quantification of angiogenic growth factors and cellular composition. Cellular composition of mesenchymal stem cells, perivascular stem cells, and endothelial progenitor cells was quantified by fluorescence activated cell sorting (FACS) analysis. Fat graft volume retention rates and fat grafting to aid wound healing were assessed. Although the presence of industry-funded studies and inadequate reporting of methodological data in some studies were sources of bias, data showed SMF grafts contain an enriched pericyte population with increased vascular endothelial growth factor (VEGF) secretion. Animal studies indicate that SMD grafts may increase rates of fat graft retention and wound closure compared to centrifuged grafts; however, clinical studies are yet to show similar results.

CONCLUSIONS

In this systematic review, we were able to conclude that the existing literature suggests mechanically processing fat, whether it be through fragmentation or disruption, improves vasculogenic potential by enhancing angiogenic growth factor and relevant vascular progenitor cell levels. Whilst in vivo animal studies are scarce, the review findings suggest that secondary mechanically processed fat enhances fat graft retention and can aid with wound healing. Further clinical studies are required to assess potential differences in human studies.

Tissue engineering and future directions in regenerative medicine for knee cartilage repair: a comprehensive review

This review evaluates the current landscape and future directions of regenerative medicine for knee cartilage repair, with a particular focus on tissue engineering strategies. In this context, scaffold-based approaches have emerged as promising solutions for cartilage regeneration. Synthetic scaffolds, while offering superior mechanical properties, often lack the biological cues necessary for effective tissue integration. Natural scaffolds, though biocompatible and biodegradable, frequently suffer from inadequate mechanical strength. Hybrid scaffolds, combining elements of both synthetic and natural materials, present a balanced approach, enhancing both mechanical support and biological functionality. Advances in decellularized extracellular matrix scaffolds have shown potential in promoting cell infiltration and integration with native tissues. Additionally, bioprinting technologies have enabled the creation of complex, bioactive scaffolds that closely mimic the zonal organization of native cartilage, providing an optimal environment for cell growth and differentiation. The review also explores the potential of gene therapy and gene editing techniques, including CRISPR-Cas9, to enhance cartilage repair by targeting specific genetic pathways involved in tissue regeneration. The integration of these advanced therapies with tissue engineering approaches holds promise for developing personalized and durable treatments for knee cartilage injuries and osteoarthritis. In conclusion, this review underscores the importance of continued multidisciplinary collaboration to advance these innovative therapies from bench to bedside and improve outcomes for patients with knee cartilage damage.

One-stage cartilage repair using the autologous matrix-induced chondrogenesis combined with simultaneous use of autologous adipose tissue graft and adipose tissue mesenchymal cells technique: clinical results and magnetic resonance imaging evaluation at five-year follow-up

PURPOSE

To evaluate medium-term outcomes of knee cartilage defects repair by autologous matrix-induced chondrogenesis combined with simultaneous use of autologous adipose tissue graft and adipose tissue mesenchymal cells, defined as LIPO-AMIC technique.

METHODS

The LIPO-AMIC technique has been used in ICRS degree III-IV knee defects. Eighteen patients have been prospectively evaluated during two and five years both clinically and by MRI.

RESULTS

Patients showed progressive significant improvement of all scores starting early at six months, and further increased values were noted till the last follow-up at 60 months. Mean subjective pre-operative IKDC score of 36.1 significantly increased to 86.4 at 24 months and to 87.2 at 60 months. Mean pre-operative Lysholm score of 44.4 reached 93.5 at two years and 93.5 at five years. MRI examination showed early subchondral lamina regrowth and progressive maturation of repair tissue and filling of defects. The mean total MOCART score showed that a significative improvement from two year follow-up (69.1 points) to last follow-up was 81.9 points (range, 30-100 points, SD 24). Complete filling of the defect at the level of the surrounding cartilage was found in 77.8%.

CONCLUSIONS

Adipose tissue can represent ideal source of MSCs since easiness of withdrawal and definite chondrogenic capacity. This study clearly demonstrated the LIPO-AMIC technique to be feasible for treatment of knee cartilage defects and to result in statistically significant progressive clinical, functional and pain improvement in all treated patients better than what reported for the AMIC standard technique, starting very early from the 6-month follow-up and maintaining the good clinical results more durably with stable results at mid-term follow-up.

Mid-term outcomes of microfragmented adipose tissue plus arthroscopic surgery for knee osteoarthritis: A randomized, active-control, multicenter clinical trial

BACKGROUND

Osteoarthritis (OA) is the most prevalent form of degenerative whole-joint disease. Before the final option of knee replacement, arthroscopic surgery was the most widely used joint-preserving surgical treatment. Emerging regenerative therapies, such as those involving platelet-rich plasma, mesenchymal stem cells, and microfragmented adipose tissue (MFAT), have been pushed to the forefront of treatment to prevent the progression of OA. Currently, MFAT has been successfully applied to treat different types of orthopedic diseases.

AIM

To assess the efficacy and safety of MFAT with arthroscopic surgery in patients with knee OA (KOA).

METHODS

A randomized, multicenter study was conducted between June 2017 and November 2022 in 10 hospitals in Zhejiang, China. Overall, 302 patients diagnosed with KOA (Kellgren-Lawrence grades 2-3) were randomized to the MFAT group (n = 151, were administered MFAT following arthroscopic surgery), or the control group (n = 151, were administered hyaluronic acid following arthroscopic surgery). The study outcomes were changes in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, the visual analog scale (VAS) score, the Lequesne index score, the Whole-Organ Magnetic Resonance Imaging Score (WORMS), and safety over a 24-mo period from baseline.

RESULTS

The changes in the WOMAC score (including the three subscale scores), VAS pain score, and Lequesne index score at the 24-mo mark were significantly different in the MFAT and control groups, as well as when comparing values at the posttreatment visit and those at baseline (P < 0.001). The MFAT group consistently demonstrated significant decreases in the WOMAC pain scores and VAS scores at all follow-ups compared to the control group (P < 0.05). Furthermore, the WOMAC stiffness score, WOMAC function score, and Lequesne index score differed significantly between the groups at 12 and 24 mo (P < 0.05). However, no significant between-group differences were observed in the WORMS at 24 mo (P = 0.367). No serious adverse events occurred in both groups.

CONCLUSION

The MFAT injection combined with arthroscopic surgery treatment group showed better mid-term clinical outcomes compared to the control group, suggesting its efficacy as a therapeutic approach for patients with KOA.

Autologous Adipose-Derived Tissue Stromal Vascular Fraction (AD-tSVF) for Knee Osteoarthritis

Adipose tissue contains adult mesenchymal stem cells that may modulate the metabolism when applied to other tissues. Stromal vascular fraction (SVF) can be isolated from adipose tissue mechanically and/or enzymatically. SVF was recently used to decrease the pain and improve the function of knee osteoarthritis (OA) patients. Primary and/or secondary OA causes inflammation and degeneration in joints, and regenerative approaches that may modify the natural course of the disease are limited. SVF may modulate inflammation and initiate regeneration in joint tissues by initiating a paracrine effect. Chemokines released from SVF may slow down degeneration and stimulate regeneration in joints. In this review, we overviewed articular joint cartilage structures and functions, OA, and macro-, micro-, and nano-fat isolation techniques. Mechanic and enzymatic SVF processing techniques were summarized. Clinical outcomes of adipose tissue derived tissue SVF (AD-tSVF) were evaluated. Medical devices that can mechanically isolate AD-tSVF were listed, and publications referring to such devices were summarized. Recent review manuscripts were also systematically evaluated and included. Transferring adipose tissues and cells has its roots in plastic, reconstructive, and aesthetic surgery. Micro- and nano-fat is also transferred to other organs and tissues to stimulate regeneration as it contains regenerative cells. Minimal manipulation of the adipose tissue is recently preferred to isolate the regenerative cells without disrupting them from their natural environment. The number of patients in the follow-up studies are recently increasing. The duration of follow up is also increasing with favorable outcomes from the short- to mid-term. There are however variations for mean age and the severity of knee OA patients between studies. Positive outcomes are related to the higher number of cells in the AD-tSVF. Repetition of injections and concomitant treatments such as combining the AD-tSVF with platelet rich plasma or hyaluronan are not solidified. Good results were obtained when combined with arthroscopic debridement and micro- or nano-fracture techniques for small-sized cartilage defects. The optimum pressure applied to the tissues and cells during filtration and purification of the AD-tSVF is not specified yet. Quantitative monitoring of articular joint cartilage regeneration by ultrasound, MR, and synovial fluid analysis as well as with second-look arthroscopy could improve our current knowledge on AD-tSVF treatment in knee OA. AD-tSVF isolation techniques and technologies have the potential to improve knee OA treatment. The duration of centrifugation, filtration, washing, and purification should however be standardized. Using gravity-only for isolation and filtration could be a reasonable approach to avoid possible complications of other methodologies.

Characterization of Microfragmented Adipose Tissue Architecture, Mesenchymal Stromal Cell Content and Release of Paracrine Mediators

The use of microfragmented adipose tissue (µFAT) for the treatment of musculoskeletal disorders, especially osteoarthritis (OA), is gaining popularity, following positive results reported in recent case series and clinical trials. Although these outcomes were postulated to rely on paracrine signals, to date, a thorough fingerprint of released molecules is largely missing. The purpose of this study was to first characterize both structure and cell content of unprocessed lipoaspirate (LA) and µFAT, and further identify and frame the array of signaling factors in the context of OA disease, by means of high throughput qRT-PCR for extracellular-vesicle (EV) embedded miRNAs and proteomics for tissue and secreted factors. Cell count showed reduction of blood cells in µFAT, confirmed by histological and flow cytometry analyses, that also showed a conserved presence of structural, endothelial and stromal components and pericytes. In the secretome, 376 and 381 EV-miRNAs in LA and µFAT, respectively, were identified. In particular, most abundant and µFAT upregulated EV-miRNAs were mainly recapitulating those already reported as ASC-EVs-specific, with crucial roles in cartilage protection and M2 macrophage polarization, while only a scarce presence of those related to blood cells emerged. Furthermore, secretome proteomic analysis revealed reduction in µFAT of acute phase factors driving OA progression. Taken together, these results suggest that processing of LA into µFAT allows for removal of blood elements and maintenance of tissue structure and stromal cell populations, and possibly the increase of OA-protective molecular features. Thus, microfragmentation represents a safe and efficient method for the application of adipose tissue properties in the frame of musculoskeletal disorders.

Autologous Microfragmented Adipose Tissue for the Treatment of Knee Osteoarthritis: Real-World Data at Two Years Follow-Up

The purpose of the present study was to assess, prospectively, the safety, clinical effectiveness, and feasibility of a single intra-articular injection of microfragmented adipose tissue in different stages of knee osteoarthritis (OA). The study included patients (aged 18−70 years), affected by OA (Kellgren−Lawrence I-IV). Unselected patients were evaluated before and prospectively after 6, 12, and 24 months from the injection. Visual analog scale (VAS) and knee injury and osteoarthritis outcome score (KOOS) were used for clinical evaluations. A total of 202 patients were eligible. The mean follow-up time in the cohort of patients was 24.5 ± 9.6 months. Total KOOS significantly improved from pre-operative baseline levels to 6-month follow-up (p < 0.001), and again between 6- and 12-month follow-ups (p < 0.001). The VAS showed a prompt reduction at 6 months (p < 0.001 vs. baseline), but then it increased again at 12 months compared to the 6-month assessment (p < 0.001), even though it remained lower than baseline (p < 0.001). At 24 months, patients with KL-IV demonstrated a lower improvement compared to baseline; patients that had undergone previous corticosteroid injections had a greater risk to further injection treatment. The collected clinical results suggest that MFAT may represent a safe and effective treatment for OA symptoms, offering a low-demanding and minimally invasive treatment.

Lipoaspirate Shows In Vitro Potential for Wound Healing

Mesenchymal stem cells (MSCs) are a promising therapy in wound healing, although extensive time and manipulation are necessary for their use. In our previous study on cartilage regeneration, we demonstrated that lipoaspirate acts as a natural scaffold for MSCs and gives rise to their spontaneous outgrowth, together with a paracrine effect on resident cells that overcome the limitations connected to MSC use. In this study, we aimed to investigate in vitro whether the microfragmented adipose tissue (lipoaspirate), obtained with Lipogems^® technology, could promote and accelerate wound healing. We showed the ability of resident cells to outgrow from the clusters of lipoaspirate encapsulated in a 3D collagen substrate as capability of repopulating a culture of human skin. Moreover, we demonstrated that the in vitro lipoaspirate paracrine effect on fibroblasts and keratinocytes proliferation, migration, and contraction rate is mediated by the release of trophic/reparative proteins. Finally, an analysis of the paracrine antibacterial effect of lipoaspirate proved its ability to secrete antibacterial factors and its ability to modulate their secretion in culture media based on a bacterial stimulus. The results suggest that lipoaspirate may be a promising approach in wound healing showing in vitro regenerative and antibacterial activities that could improve current therapeutic strategies.

Intra-Articular Injection of Autologous Microfat and Platelet-Rich Plasma in the Treatment of Knee Osteoarthritis: A Double-Blind Randomized Comparative Study

PURPOSE

To compare a single abdominal microfat (MF) injection mixed or not with platelet-rich plasma (PRP) Low Dose (LD) or High Dose (HD) in order to improve MRI parameters, alleviate pain and enhance functional capacity in knee osteoarthritis.

METHODS

Patients with symptomatic grade 2 to 4 knee osteoarthritis according to the International Cartilage Repair Society MRI classification were selected. They were prospectively assessed at baseline and at 3 and 6 months of follow-up. The primary endpoint was change in the maximum of value of cartilage relaxation time in T2 mapping sequences (T2max) at 3 months. Secondary endpoints were MRI grade severity and joint space assessment, Western Ontario and McMaster Universities Arthritis Index score, pain evaluation, knee range of motion, and patients' satisfaction. Adverse events were also collected. The complete cell counts and growth factors content of injected products were assessed to analyze their potential relationship with MRI and clinical outcomes.

RESULTS

Three groups of 10 patients received a single injection of 10 cc of a mix (1:1) containing MF-Saline, MF-PRP LD or MF-PRP HD. T2max did not change significantly over the time for any of the groups. All treatments significantly improved knee functional status and symptom relief at 3 and 6 months. All patients were responders in the MF/PRP HD at 3 months and significantly higher compared to MF/PRP LD. Half of the injected PRP in the MF/PRP LD group displayed red blood cell contamination of over 8%, which was correlated with an impairment of T2max.

CONCLUSION

A single intra-articular injection of MF with or without PRP is safe and may offer a significant clinical improvement in patients with osteoarthritis.

LEVEL OF EVIDENCE

2; randomized double-blind comparative parallel-group trial (RCT No.: NCT04352075).

Microfragmented adipose tissue is associated with improved ex vivo performance linked to HOXB7 and b-FGF expression

INTRODUCTION

Adipose tissue (AT) has become a source of mesenchymal stromal/stem cells (MSC) for regenerative medicine applications, in particular skeletal disorders. Several enzymatic or mechanical procedures have been proposed to process AT with the aim to isolate cells that can be locally implanted. How AT is processed may impact its properties. Thus, we compared AT processed by centrifugation (C-AT) to microfragmentation (MF-AT). Focusing on MF-AT, we subsequently assessed the impact of synovial fluid (SF) alone on both MF-AT and isolated AT-MSC to better understand their cartilage repair mechanisms.

MATERIALS AND METHODS

MF-AT and C-AT from the same donors were compared by histology and qRT-PCR immediately after isolation or as ex vivo cultures using a micro-tissue pellet system. The in vitro impact of SF on MF-AT and AT-MSC was assessed by histological staining and molecular analysis.

RESULTS

The main AT histological features (i.e., increased extracellular matrix and cellularity) of the freshly isolated or ex vivo-cultured MF-AT persisted compared to C-AT, which rapidly deteriorated during culture. Based on our previous studies of HOX genes in MSC, we investigated the involvement of Homeobox Protein HOX-B7 (HOXB7) and its target basic Fibroblast Growth Factor (bFGF) in the molecular mechanism underlying the improved performance of MF-AT. Indeed, both these biomarkers were more prominent in freshly isolated MF-AT compared to C-AT. SF alone preserved the AT histological features of MF-AT, together with HOXB7 and bFGF expression. Increased cell performance was also observed in isolated AT-MSC after SF treatment concomitant with enhanced HOXB7 expression, although there was no apparent association with bFGF.

CONCLUSIONS

Our findings show that MF has a positive effect on the maintenance of AT histology and may trigger the expression of trophic factors that improve tissue repair by processed AT.

New Trends in Injection-Based Therapy for Thumb-Base Osteoarthritis: Where Are We and where Are We Going?

Thumb-base osteoarthritis (TBOA) is a common condition, mostly affecting post-menopausal women, often inducing a significant impact on quality of life and hand functionality. Despite its high prevalence and disability, the therapeutic options in TBOA are still limited and few have been investigated. Among the pharmacological strategies for TBOA management, it would be worthwhile to mention the injection-based therapy. Unfortunately, its efficacy is still the subject of debate. Indeed, the 2018 update of the European League Against Rheumatism (EULAR) recommendations for the management of hand osteoarthritis (OA) stated that intra-articular (IA) injections of glucocorticoids should not generally be used, but may be considered in patients with painful interphalangeal joints, without any specific mention to the TBOA localization and to other widely used injections agents, such as hyaluronic acid (HA) and platelet-rich plasma (PRP). Even American College of Rheumatology (ACR) experts conditionally recommended against IA HA injections in patients with TBOA, while they conditionally encouraged IA glucocorticoids. However, the recommendations from international scientific societies don’t often reflect the clinical practice of physicians who routinely take care of TBOA patients; indeed, corticosteroid injections are a mainstay of therapy in OA, especially for patients with pain refractory to oral treatments and HA is considered as a safe and effective treatment. The discrepancy with the literature data is due to the great heterogeneity of the clinical trials published in this field: indeed, the studies differ for methodology and protocol design, outcome measures, treatment (different formulations of HA, steroids, PRP, and schedules) and times of follow-up. For these reasons, the current review will provide deep insight into the injection-based therapy for TBOA, with particular attention to the different employed agents, the variety of the schedule treatments, the most common injection techniques, and the obtained results in terms of efficacy and safety. In depth, we will discuss the available literature on corticosteroids and HA injections for TBOA and the emerging role of PRP and other injection agents for this condition. We will consider in our analysis not only randomized controlled trials (RCTs) but also recent pilot or retrospective studies trying to step forward to identify satisfactory management strategies for TBOA.

Autologous fat transplantation for the treatment of trapeziometacarpal joint osteoarthritis

Rhizarthrosis is a progressive and disabling pathology affecting the carpometacarpal joint. It's very common in elderly patients and typically affects postmenopausal women. The diagnosis of rhizarthrosis is mainly made by using different physical examination tests and by evaluating the type of pain and it's then confirmed by imaging. Over the last few years increasing attention has been devoted to the assessment of new treatment techniques for rhizarthrosis. In this context intra-articular injection of autologous fat grafting for cartilage regeneration has demonstrated promising results in experimental settings as an alternative to open surgery procedures. The aim of this study was therefore to sum up the evidences available so far on autologous fat grafting as an emerging treatment for patients affected by carpometacarpal rizarthrosis. An electronic literature research was carried out on Pubmed, Google Scholars and Cochrane Library using "fat grafting", "fat graft", "adipose", "fat transfer" and "lipoaspirate" as search terms. Authors believe autologous fat grafting is an interesting technique, that hand surgeon should keep in mind especially in early stages of rhizarthrosis were pain has not been solved with non-surgical treatment.

One-Year Outcomes of Intraarticular Fat Transplantation for Thumb Carpometacarpal Joint Osteoarthritis: Case Review of 99 Joints

BACKGROUND

This study aims to present a new therapeutic option for the treatment of thumb carpometacarpal joint osteoarthritis. Knowing that autologous fat may be beneficial for osteoarthritis through antiinflammatory and chondroprotective effects, the authors transplanted autologous adipose fat into the thumb carpometacarpal joint with the objective of postponing definite resection arthroplasty surgery.

METHODS

In this pilot study, the authors performed surgery on 99 joints. The study population consisted of patients with symptomatic and radiologically confirmed osteoarthritis of the thumb carpometacarpal joint. After harvesting abdominal adipose tissue, 1 to 2 ml of fat without physical or enzymatic manipulation were transplanted into the thumb carpometacarpal joint. Surgical outcome was quantified by use of the Michigan Hand Outcomes Questionnaire in addition to strength and pain measurements during a 12-month follow-up consultation. We conducted Friedman's analysis of variance to gauge the differences over time regarding Michigan Hand Outcomes Questionnaire and pain under stress.

RESULTS

From 2 weeks on, there was pain relief, both under stress and at rest. Friedman's analysis of variance revealed a significant change in pain under stress [chi-square (5) = 68.52; p < 0.001]. Postoperative Michigan Hand Outcomes Questionnaire Scores improved significantly over 12 months [chi-square (5) = 90.56; p < 0.001].

CONCLUSION

The authors' preliminary findings suggest that intraarticular autologous fat transplantation is a promising alternative treatment of carpometacarpal joint osteoarthritis of the thumb.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Therapeutic "Tool" in Reconstruction and Regeneration of Tissue Engineering for Osteochondral Repair

Repairing osteochondral defects to restore joint function is a major challenge in regenerative medicine. However, with recent advances in tissue engineering, the development of potential treatments is promising. In recent years, in addition to single-layer scaffolds, double-layer or multilayer scaffolds have been prepared to mimic the structure of articular cartilage and subchondral bone for osteochondral repair. Although there are a range of different cells such as umbilical cord stem cells, bone marrow mesenchyml stem cell, and others that can be used, the availability, ease of preparation, and the osteogenic and chondrogenic capacity of these cells are important factors that will influence its selection for tissue engineering. Furthermore, appropriate cell proliferation and differentiation of these cells is also key for the optimal repair of osteochondral defects. The development of bioreactors has enhanced methods to stimulate the proliferation and differentiation of cells. In this review, we summarize the recent advances in tissue engineering, including the development of layered scaffolds, cells, and bioreactors that have changed the approach towards the development of novel treatments for osteochondral repair.

Autologous Micro-Fragmented Adipose Tissue as Stem Cell-Based Natural Scaffold for Cartilage Defect Repair

Osteoarthritis (OA) poses a tough challenge worldwide. Adipose-derived stem cells (ASCs) have been proved to play a promising role in cartilage repair. However, enzymatic digestion, ex vivo culture and expansion, with significant senescence and decline in multipotency, limit their application. The present study was designed to obtain micro-fragmented adipose tissue (MFAT) through gentle mechanical force and determine the effect of this stem cell-based natural scaffold on repair of full-thickness cartilage defects. In this study, ASCs sprouted from MFAT were characterized by multi-differentiation induction and flow cytometry. Scratch and transwell migration assays were operated to determine whether MFAT could promote migration of chondrocytes in vitro. In a rat model, cartilage defects were created on the femoral groove and treated with intra-articular injection of MFAT or PBS for 6 weeks and 12 weeks (n = 12). At the time points, the degree of cartilage repair was evaluated by histological staining, immunohistochemistry and scoring, respectively. Two unoperated age-matched animals served as native controls. ASCs derived from MFAT possessed properties to differentiate into adipocytes, osteocytes and chondrocytes, with expression of mesenchymal stem cell markers (CD29, 44, 90) and no expression of hematopoietic markers (CD31, 34, 45). In addition, MFAT could significantly promote migration of chondrocytes. MFAT-treated defects showed improved macroscopic appearance and histological evaluation compared with PBS-treated defects at both time points. After 12 weeks of treatment, MFAT-treated defects displayed regular surface, high amount of hyaline cartilage, intact subchondral bone reconstruction and corresponding formation of type I, II, and VI collagen, which resembled the normal cartilage. This study demonstrates the efficacy of MFAT on cartilage repair in an animal model for the first time, and the utility of MFAT as a ready-to-use therapeutic alternative to traditional stem cell therapy.

Adipose-Derived Mesenchymal Stem Cells: A Promising Tool in the Treatment of Musculoskeletal Diseases

Chronic musculoskeletal (MSK) pain is one of the most common medical complaints worldwide and musculoskeletal injuries have an enormous social and economical impact. Current pharmacological and surgical treatments aim to relief pain and restore function; however, unsatiscactory outcomes are commonly reported. In order to find an accurate treatment to such pathologies, over the last years, there has been a significantly increasing interest in cellular therapies, such as adipose-derived mesenchymal stem cells (AMSCs). These cells represent a relatively new strategy in regenerative medicine, with many potential applications, especially regarding MSK disorders, and preclinical and clinical studies have demonstrated their efficacy in muscle, tendon, bone and cartilage regeneration. Nevertheless, several worries about their safety and side effects at long-term remain unsolved. This article aims to review the current state of AMSCs therapy in the treatment of several MSK diseases and their clinical applications in veterinary and human medicine.

Development of Autologous Platelet-Rich Plasma Mixed-Microfat as an Advanced Therapy Medicinal Product for Intra-Articular Injection of Radio-Carpal Osteoarthritis: From Validation Data to Preliminary Clinical Results

Wrist osteoarthritis (OA) is one of the most common conditions encountered by hand surgeons with limited efficacy of non-surgical treatments. The purpose of this study is to describe the Platelet-Rich Plasma (PRP) mixed-microfat biological characteristics of an experimental Advanced Therapy Medicinal Product (ATMP) needed for clinical trial authorization and describe the clinical results obtained from our first three patients 12 months after treatment (NCT03164122). Biological characterization of microfat, PRP and mixture were analysed in vitro according to validated methods. Patients with stage four OA according to the Kellgren Lawrence classification, with failure to conservative treatment and a persistent daily painful condition >40 mm according to the visual analog scale (VAS) were treated. Microfat-PRP ATMP is a product with high platelet purity, conserved viability of stromal vascular fraction cells, chondrogenic differentiation capacity in vitro and high secretion of IL-1Ra anti-inflammatory cytokine. For patients, the only side effect was pain at the adipose tissue harvesting sites. Potential efficacy was observed with a pain decrease of over 50% (per VAS score) and the achievement of minimal clinically important differences for DASH and PRWE functional scores at one year in all three patients. Microfat-PRP ATMP presented a good safety profile after an injection in wrist OA. Efficacy trials are necessary to assess whether this innovative strategy could delay the necessity to perform non-conservative surgery.

Intra-Articular Administration of Autologous Micro-Fragmented Adipose Tissue in Dogs with Spontaneous Osteoarthritis: Safety, Feasibility, and Clinical Outcomes

Similar to the disease affecting humans, osteoarthritis (OA) is a painful musculoskeletal condition affecting 20% of the adult canine population. Several solutions have been proposed, but the results achieved to date are far from being satisfactory. New approaches, such as intra-articular delivery of cells (including mesenchymal stromal cells), have been proposed. Among the many sources, the adipose tissue is considered very promising. We evaluated the safety, feasibility, and efficacy of a single intra-articular injection of autologous and micro-fragmented adipose tissue (MFAT) in 130 dogs with spontaneous OA. MFAT was obtained using a minimally invasive technique in a closed system and injected in the intra- and/or peri-articular space. Clinical outcomes were determined using orthopedic examination and owners' scores for up to 6 months. In 78% of the dogs, improvement in the orthopedic score was registered 1 month after treatment and continued gradually up to 6 months when 88% of the dogs improved, 11% did not change, and 1% worsened compared with baseline. Considering the owners' scores at 6 months, 92% of the dogs significantly improved, 6% improved only slightly, and 2% worsened compared with baseline. No local or systemic major adverse effects were recorded. The results of this study suggest that MFAT injection in dogs with OA is safe, feasible, and beneficial. The procedure is time sparing and cost-effective. Post injection cytological investigation, together with the clinical evidence, suggests a long-term pain control role of this treatment. The spontaneous OA dog model has a key role in developing successful treatments for translational medicine. Stem Cells Translational Medicine 2018;7:819-828.

A randomized, controlled study to evaluate the efficacy of intra-articular, autologous adipose tissue injections for the treatment of mild-to-moderate knee osteoarthritis compared to hyaluronic acid: a study protocol

BACKGROUND

Osteoarthritis (OA) is a highly debilitating joint disease that causes progressive, irreversible damage to articular cartilage. OA takes a massive toll on society that has grown in recent decades, but no therapy has been shown to halt or reverse the progression of the disease. The critical need for better treatments and increased interest cellular therapies has spawned a new generation of "minimally manipulated" cell treatments. Autologous adipose tissue injections are among the most controversial of these new treatments. Despite a lack of clinical evidence, adipose tissue injections are often marketed as "stem cell" injections with wide-ranging regenerative benefits. The purpose of this study is to estimate the effect size of the treatment by comparing the efficacy of autologous fat to hyaluronic acid (HA). As a secondary aim, we will test for preliminary evidence of efficacy of autologous fat vs. HA.

METHODS

This is a prospective, single-center, parallel-group, randomized, controlled trial. Participants (n = 54) will receive either a single intra-articular, ultrasound-guided injection of autologous adipose tissue or a single intra-articular, ultrasound-guided injection of HA (1:1 ratio). Outcome data will be obtained at baseline, week-6 and month-6. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain domain (WOMAC-A) will be used as the primary outcome measure. Secondary clinical outcome measures include WOMAC (full), clinical anchors (pain, function, and stiffness), and the 29-point Patient-Reported Outcomes Measurement Information System (PROMIS®) profile. We will also take synovial fluid samples and assess sway velocity using a force plate, as well as analyze excess/discard adipose tissue to gain a better understanding of how intra-articular adipose tissue injections influence the biochemical environment of the joint.

DISCUSSION

Given the widespread use of intra-articular fat injections in the United States, it is critical that randomized, controlled human studies evaluating efficacy and biological activity be performed. This study is the first step in addressing this unmet need, but it is not without limitations. The most notable limitations of this study are its small size and lack of blinding, which predisposes the study to both investigator and participant bias.

TRIAL REGISTRATION

NCT03242707 // HS-17-00365 // Registration Date (First Posted): August 8, 2018.

Concentrated adipose tissue infusion for the treatment of knee osteoarthritis: clinical and histological observations

PURPOSE

Osteoarthritis (OA) is characterized by articular cartilage degeneration and subchondral bone sclerosis. OA can benefit of non-surgical treatments with collagenase-isolated stromal vascular fraction (SVF) or cultured-expanded mesenchymal stem cells (ASCs). To avoid high manipulation of the lipoaspirate needed to obtain ASCs and SVF, we investigated whether articular infusions of autologous concentrated adipose tissue are an effective treatment for knee OA patients.

METHODS

The knee of 20 OA patients was intra-articularly injected with autologous concentrated adipose tissue, obtained after centrifugation of lipoaspirate. Patients' articular functionality and pain were evaluated by VAS and WOMAC scores at three, six and 18 months from infusion. The osteogenic and chondrogenic ability of ASCs contained in the injected adipose tissue was studied in in vitro primary osteoblast and chondrocyte cell cultures, also plated on 3D-bone scaffold. Knee articular biopsies of patients previously treated with adipose tissue were analyzed. Immunohistochemistry (IHC) and scanning electron microscopy (SEM) were performed to detect cell differentiation and tissue regeneration.

RESULTS

The treatment resulted safe, and all patients reported an improvement in terms of pain reduction and increase of function. According to the osteogenic or chondrogenic stimulation, ASCs expressed alkaline phosphatase or aggrecan, respectively. The presence of a layer of newly formed tissue was visualized by IHC staining and SEM. The biopsy of previously treated knee joints showed new tissue formation, starting from the bone side of the osteochondral lesion.

CONCLUSIONS

Overall our data indicate that adipose tissue infusion stimulates tissue regeneration and might be considered a safe treatment for knee OA.

Injections for Knee Osteoarthritis: Corticosteroids, Viscosupplementation, Platelet-Rich Plasma, and Autologous Stem Cells

This article reviews the benefits of corticosteroid, viscosupplementation, platelet-rich plasma, and autologous mesenchymal stem cell injections for the treatment of patients with knee osteoarthritis. Integrating injections into both clinical and surgical practices is complicated given existing health insurance reimbursement policies. This review describes the outcomes associated with these interventions and appropriate methods of navigating the existing reimbursement pathways to help providers implement these treatments into their practices.

Adipose Tissue and Mesenchymal Stem Cells: State of the Art and Lipogems® Technology Development

In the past few years, interest in adipose tissue as an ideal source of mesenchymal stem cells (MSCs) has increased. These cells are multipotent and may differentiate in vitro into several cellular lineages, such as adipocytes, chondrocytes, osteoblasts, and myoblasts. In addition, they secrete many bioactive molecules and thus are considered "mini-drugstores." MSCs are being used increasingly for many clinical applications, such as orthopedic, plastic, and reconstructive surgery. Adipose-derived MSCs are routinely obtained enzymatically from fat lipoaspirate as SVF and/or may undergo prolonged ex vivo expansion, with significant senescence and a decrease in multipotency, leading to unsatisfactory clinical results. Moreover, these techniques are hampered by complex regulatory issues. Therefore, an innovative technique (Lipogems®; Lipogems International SpA, Milan, Italy) was developed to obtain microfragmented adipose tissue with an intact stromal vascular niche and MSCs with a high regenerative capacity. The Lipogems® technology, patented in 2010 and clinically available since 2013, is an easy-to-use system designed to harvest, process, and inject refined fat tissue and is characterized by optimal handling ability and a great regenerative potential based on adipose-derived MSCs. In this novel technology, the adipose tissue is washed, emulsified, and rinsed and adipose cluster dimensions gradually are reduced to about 0.3 to 0.8 mm. In the resulting Lipogems® product, pericytes are retained within an intact stromal vascular niche and are ready to interact with the recipient tissue after transplantation, thereby becoming MSCs and starting the regenerative process. Lipogems® has been used in more than 7000 patients worldwide in aesthetic medicine and surgery, as well as in orthopedic and general surgery, with remarkable and promising results and seemingly no drawbacks. Now, several clinical trials are under way to support the initial encouraging outcomes. Lipogems® technology is emerging as a valid intraoperative system to obtain an optimal final product that may be used immediately for regenerative purposes.

Mesenchymal Stem Cells in Lipogems, a Reverse Story: from Clinical Practice to Basic Science

The idea that basic science should be the starting point for modern clinical approaches has been consolidated over the years, and emerged as the cornerstone of Molecular Medicine. Nevertheless, there is increasing concern over the low efficiency and inherent costs related to the translation of achievements from the bench to the bedside. These burdens are also perceived with respect to the effectiveness of translating basic discoveries in stem cell biology to the newly developing field of advanced cell therapy or Regenerative Medicine. As an alternative paradigm, past and recent history in Medical Science provides remarkable reverse stories in which clinical observations at the patient's bedside have fed major advances in basic research which, in turn, led to consistent progression in clinical practice. Within this context, we discuss our recently developed method and device, which forms the core of a system (Lipogems) for processing of human adipose tissue solely with the aid of mild mechanical forces to yield a microfractured tissue product.