A comparative assessment of adipose-derived stem cells from subcutaneous and visceral fat as a potential cell source for knee osteoarthritis treatment

Mesenchymal Stromal Cells for Aging Cartilage Regeneration: A Review

Cartilage degeneration is a key feature of aging and osteoarthritis, characterized by the progressive deterioration of joint function, pain, and limited mobility. Current treatments focus on symptom relief, not cartilage regeneration. Mesenchymal stromal cells (MSCs) offer a promising therapeutic option due to their capability to differentiate into chondrocytes, modulate inflammation, and promote tissue regeneration. This review explores the potential of MSCs for cartilage regeneration, examining their biological properties, action mechanisms, and applications in preclinical and clinical settings. MSCs derived from bone marrow, adipose tissue, and other sources can self-renew and differentiate into multiple cell types. In aging cartilage, they aid in tissue regeneration by secreting growth factors and cytokines that enhance repair and modulate immune responses. Recent preclinical studies show that MSCs can restore cartilage integrity, reduce inflammation, and improve joint function, although clinical translation remains challenging due to limitations such as cell viability, scalability, and regulatory concerns. Advancements in MSC delivery, including scaffold-based approaches and engineered exosomes, may improve therapeutic effectiveness. Potential risks, such as tumorigenicity and immune rejection, are also discussed, emphasizing the need for optimized treatment protocols and large-scale clinical trials to develop effective, minimally invasive therapies for cartilage regeneration.

Differentiation of Human Mesenchymal Stem Cells into Corneal Epithelial Cells: Current Progress

The limited availability of corneal tissue grafts poses significant challenges in the treatment of corneal blindness. Novel treatment utilizes stem cell grafts transplanted from the healthy side of the cornea to the damaged side. However, this procedure is only possible for those who have one-sided corneal blindness. Human stem cells offer promising potential for corneal tissue engineering, providing an alternative solution. Among the different types of stem cells, mesenchymal stem cells (MSCs) stand out due to their abundance and ease of isolation. Human MSCs can be derived from bone marrow, adipose, and umbilical cord tissues. Differentiating MSC toward corneal tissue can be achieved through several methods including chemical induction and co-culture with adult corneal cells such as human limbal epithelial stem cells (LESCs) and human corneal epithelial cells (hTCEpi). Adipose-derived stem cells (ADSCs) are the most common type of MSC that has been studied for corneal differentiation. Corneal epithelial cells are the most common corneal cell type targeted by researchers for corneal differentiation. Chemical induction with small molecules, especially bone morphogenetic protein 4 (BMP4), all-trans retinoic acid (ATRA), and epidermal growth factor (EGF), has gained more popularity in corneal epithelial cell differentiation. This review highlights the current progress in utilizing MSCs for corneal differentiation studies, showcasing their potential to revolutionize treatments for corneal blindness.

Mutations in fibronectin dysregulate chondrogenesis in skeletal dysplasia

Fibronectin (FN) is an extracellular matrix glycoprotein essential for the development and function of major vertebrate organ systems. Mutations in FN result in an autosomal dominant skeletal dysplasia termed corner fracture-type spondylometaphyseal dysplasia (SMDCF). The precise pathomechanisms through which mutant FN induces impaired skeletal development remain elusive. Here, we have generated patient-derived induced pluripotent stem cells as a cell culture model for SMDCF to investigate the consequences of FN mutations on mesenchymal stem cells (MSCs) and their differentiation into cartilage-producing chondrocytes. In line with our previous data, FN mutations disrupted protein secretion from MSCs, causing a notable increase in intracellular FN and a significant decrease in extracellular FN levels. Analyses of plasma samples from SMDCF patients also showed reduced FN in circulation. FN and endoplasmic reticulum (ER) protein folding chaperones (BIP, HSP47) accumulated in MSCs within ribosome-covered cytosolic vesicles that emerged from the ER. Massive amounts of these vesicles were not cleared from the cytosol, and a smaller subset showed the presence of lysosomal markers. The accumulation of intracellular FN and ER proteins elevated cellular stress markers and altered mitochondrial structure. Bulk RNA sequencing revealed a specific transcriptomic dysregulation of the patient-derived cells relative to controls. Analysis of MSC differentiation into chondrocytes showed impaired mesenchymal condensation, reduced chondrogenic markers, and compromised cell proliferation in mutant cells. Moreover, FN mutant cells exhibited significantly lower transforming growth factor beta-1 (TGFβ1) expression, crucial for mesenchymal condensation. Exogenous FN or TGFβ1 supplementation effectively improved the MSC condensation and promoted chondrogenesis in FN mutant cells. These findings demonstrate the cellular consequences of FN mutations in SMDCF and explain the molecular pathways involved in the associated altered chondrogenesis.

Advancements in culture technology of adipose-derived stromal/stem cells: implications for diabetes and its complications

Stem cell-based therapies exhibit considerable promise in the treatment of diabetes and its complications. Extensive research has been dedicated to elucidate the characteristics and potential applications of adipose-derived stromal/stem cells (ASCs). Three-dimensional (3D) culture, characterized by rapid advancements, holds promise for efficacious treatment of diabetes and its complications. Notably, 3D cultured ASCs manifest enhanced cellular properties and functions compared to traditional monolayer-culture. In this review, the factors influencing the biological functions of ASCs during culture are summarized. Additionally, the effects of 3D cultured techniques on cellular properties compared to two-dimensional culture is described. Furthermore, the therapeutic potential of 3D cultured ASCs in diabetes and its complications are discussed to provide insights for future research.

Extracellular vesicles derived from mesenchymal stem cells mediate extracellular matrix remodeling in osteoarthritis through the transport of microRNA-29a

BACKGROUND

Knee osteoarthritis (KOA) is a common orthopedic condition with an uncertain etiology, possibly involving genetics and biomechanics. Factors like changes in chondrocyte microenvironment, oxidative stress, inflammation, and immune responses affect KOA development. Early-stage treatment options primarily target symptom relief. Mesenchymal stem cells (MSCs) show promise for treatment, despite challenges. Recent research highlights microRNAs (miRNAs) within MSC-released extracellular vesicles that can potentially promote cartilage regeneration and hinder KOA progression. This suggests exosomes (Exos) as a promising avenue for future treatment. While these findings emphasize the need for effective KOA progression management, further safety and efficacy validation for Exos is essential.

AIM

To explore miR-29a's role in KOA, we'll create miR-29a-loaded vesicles, testing for early treatment in rat models.

METHODS

Extraction of bone marrow MSC-derived extracellular vesicles, preparation of engineered vesicles loaded with miR-29a using ultrasonication, and identification using quantitative reverse transcription polymerase chain reaction; after establishing a rat model of KOA, rats were randomly divided into three groups: Blank control group injected with saline, normal extracellular vesicle group injected with normal extracellular vesicle suspension, and engineered extracellular vesicle group injected with engineered extracellular vesicle suspension. The three groups were subjected to general behavioral observation analysis, imaging evaluation, gross histological observation evaluation, histological detection, and immunohistochemical detection to compare and evaluate the progress of various forms of arthritis.

RESULTS

General behavioral observation results showed that the extracellular vesicle group and engineered extracellular vesicle group had better performance in all four indicators of pain, gait, joint mobility, and swelling compared to the blank control group. Additionally, the engineered extracellular vesicle group had better pain relief at 4 wk and better knee joint mobility at 8 wk compared to the normal extracellular vesicle group. Imaging examination results showed that the blank control group had the fastest progression of arthritis, the normal extracellular vesicle group had a relatively slower progression, and the engineered extracellular vesicle group had the slowest progression. Gross histological observation results showed that the blank control group had the most obvious signs of arthritis, the normal extracellular vesicle group showed signs of arthritis, and the engineered extracellular vesicle group showed no significant signs of arthritis. Using the Pelletier gross score evaluation, the engineered extracellular vesicle group had the slowest progression of arthritis. Results from two types of staining showed that the articular cartilage of rats in the normal extracellular vesicle and engineered extracellular vesicle groups was significantly better than that of the blank control group, and the engineered extracellular vesicle group had the best cartilage cell and joint surface condition. Immunohistochemical detection of type II collagen and proteoglycan showed that the extracellular matrix of cartilage cells in the normal extracellular vesicle and engineered extracellular vesicle groups was better than that of the blank control group. Compared to the normal extracellular vesicle group, the engineered extracellular vesicle group had a better regulatory effect on the extracellular matrix of cartilage cells.

CONCLUSION

Engineered Exos loaded with miR-29a can exert anti-inflammatory effects and maintain extracellular matrix stability, thereby protecting articular cartilage, and slowing the progression of KOA.

Impact of Adipose Tissue Depot Harvesting Site on the Multilineage Induction Capacity of Male Rat Adipose-Derived Mesenchymal Stem Cells: An In Vitro Study

Recently, substantial attention has been paid toward adipose-derived mesenchymal stem cells (AdMSCs) as a potential therapy in tissue engineering and regenerative medicine applications. Rat AdMSCs (r-AdMSCs) are frequently utilized. However, the influence of the adipose depot site on the multilineage differentiation potential of the r-AdMSCs is still ambiguous. Hence, the main objective of this study was to explore the influence of the adipose tissue harvesting location on the ability of r-AdMSCs to express the stem-cell-related markers and pluripotency genes, as well as their differentiation capacity, for the first time. Herein, we have isolated r-AdMSCs from the inguinal, epididymal, peri-renal, and back subcutaneous fats. Cells were compared in terms of their phenotype, immunophenotype, and expression of pluripotency genes using RT-PCR. Additionally, we investigated their potential for multilineage (adipogenic, osteogenic, and chondrogenic) induction using special stains confirmed by the expression of the related genes using RT-qPCR. All cells could positively express stem cell marker CD 90 and CD 105 with no significant in-between differences. However, they did not express the hematopoietic markers as CD 34 and CD 45. All cells could be induced successfully. However, epididymal and inguinal cells presented the highest capacity for adipogenic and osteogenic differentiation (21.36-fold and 11.63-fold for OPN, 29.69-fold and 26.68-fold for BMP2, and 37.67-fold and 22.35-fold for BSP, respectively, in epididymal and inguinal cells (p < 0.0001)). On the contrary, the subcutaneous cells exhibited a superior potential for chondrogenesis over the other sites (8.9-fold for CHM1 and 5.93-fold for ACAN, (p < 0.0001)). In conclusion, the adipose tissue harvesting site could influence the differentiation capacity of the isolated AdMSCs. To enhance the results of their employment in various regenerative cell-based therapies, it is thus vital to take the collection site selection into consideration.

Cartilage 3D bioprinting for rhinoplasty using adipose-derived stem cells as seed cells: Review and recent advances

Nasal deformities due to various causes affect the aesthetics and use of the nose, in which case rhinoplasty is necessary. However, the lack of cartilage for grafting has been a major problem and tissue engineering seems to be a promising solution. 3D bioprinting has become one of the most advanced tissue engineering methods. To construct ideal cartilage, bio-ink, seed cells, growth factors and other methods to promote chondrogenesis should be considered and weighed carefully. With continuous progress in the field, bio-ink choices are becoming increasingly abundant, from a single hydrogel to a combination of hydrogels with various characteristics, and more 3D bioprinting methods are also emerging. Adipose-derived stem cells (ADSCs) have become one of the most popular seed cells in cartilage 3D bioprinting, owing to their abundance, excellent proliferative potential, minimal morbidity during harvest and lack of ethical considerations limitations. In addition, the co-culture of ADSCs and chondrocytes is commonly used to achieve better chondrogenesis. To promote chondrogenic differentiation of ADSCs and construct ideal highly bionic tissue-engineered cartilage, researchers have used a variety of methods, including adding appropriate growth factors, applying biomechanical stimuli and reducing oxygen tension. According to the process and sequence of cartilage 3D bioprinting, this review summarizes and discusses the selection of hydrogel and seed cells (centered on ADSCs), the design of printing, and methods for inducing the chondrogenesis of ADSCs.

An observational study evaluating the efficacy of microfragmented adipose tissue in the treatment of osteoarthritis

Aim: Osteoarthritis (OA) prevalence is increased in ageing and obese populations. This prospective single-arm cohort study aimed to investigate the efficacy of autologous microfragmented adipose tissue treatment of severe knee or shoulder OA. Materials & methods: Participants received an intra-articular microfragmented adipose tissue injection to the affected joint(s). Multiple patient reported outcome measures (PROMS) were recorded from 0 to 52 weeks for 63 consecutive joints. Results: Compared with baseline, there were significant improvements in all PROMS from 2 to 12 weeks and maintained at 52 weeks. Regression analysis revealed an inverse correlation with BMI and change in PROMS for knee joints. Conclusion: Our observed findings suggest this approach represents a safe, effective treatment for moderate-to-severe knee and shoulder OA, although efficacy may be reduced with increasing obesity.

Cell-based therapies have disease-modifying effects on osteoarthritis in animal models. A systematic review by the ESSKA Orthobiologic Initiative. Part 1: adipose tissue-derived cell-based injectable therapies

PURPOSE

The aim of this systematic review was to determine if adipose tissue-derived cell-based injectable therapies can induce disease-modifying effects in joints affected by osteoarthritis (OA).

METHODS

A systematic review was performed on three electronic databases (PubMed, Web of Science, Embase) according to PRISMA guidelines. A synthesis of the results was performed investigating disease-modifying effects in preclinical studies comparing injectable adipose-derived products with OA controls or other products, different formulations or injection intervals, and the combination with other products. The risk of bias was assessed according to the SYRCLE's tool.

RESULTS

Seventy-one studies were included (2,086 animals) with an increasing publication trend over time. Expanded cells were used in 65 studies, 3 studies applied point of care products, and 3 studies investigated both approaches. Overall, 48 out of 51 studies (94%) reported better results with adipose-derived products compared to OA controls, with positive findings in 17 out of 20 studies (85%) in macroscopic, in 37 out of 40 studies (93%) in histological, and in 22 out of 23 studies (96%)  in immunohistochemical evaluations. Clinical and biomarker evaluations showed positive results in 14 studies out of 18 (78%) and 12 studies out of 14 (86%), while only 9 studies out of 17 (53%) of the imaging evaluations were able to detect differences versus controls. The risk of bias was low in 38% of items, unclear in 51%, and high in (11%).

CONCLUSION

The current preclinical models document consistent evidence of disease-modifying effects of adipose-derived cell-based therapies for the treatment of OA. The high heterogeneity of the published studies highlights the need for further targeted research to provide recommendations on the optimal methodologies for a more effective application of these injective therapies for the treatment of OA in clinical practice.

LEVEL OF EVIDENCE

II.

Preclinical studies and clinical trials on mesenchymal stem cell therapy for knee osteoarthritis: A systematic review on models and cell doses

AIM

To provide a systematic analysis of the study design in knee osteoarthritis (OA) preclinical studies, focusing on the characteristics of animal models and cell doses, and to compare these to the characteristics of clinical trials using mesenchymal stem cells (MSCs) for the treatment of knee OA.

METHOD

A systematic and comprehensive search was conducted using the PubMed, Web of Science, Ovid, and Embase electronic databases for research papers published in 2009-2020 on testing MSC treatment in OA animal models. The PubMed database and ClinicalTrials.gov website were used to search for published studies reporting clinical trials of MSC therapy for knee OA.

RESULTS

In total, 9234 articles and two additional records were retrieved, of which 120 studies comprising preclinical and clinical studies were included for analysis. Among the preclinical studies, rats were the most commonly used species for modeling knee OA, and anterior cruciate ligament transection was the most commonly used method for inducing OA. There was a correlation between the cell dose and body weight of the animal. In clinical trials, there was large variation in the dose of MSCs used to treat knee OA, ranging from 1 × 10⁶ to 200 × 10⁶ cells with an average of 37.91 × 10⁶ cells.

CONCLUSION

Mesenchymal stem cells have shown great potential in improving pain relief and tissue protection in both preclinical and clinical studies of knee OA. Further high-quality preclinical and clinical studies are needed to explore the dose effectiveness relationship of MSC therapy and to translate the findings from preclinical studies to humans.

Distinct Characteristics Between Perivascular and Subcutaneous Adipose-Derived Stem Cells

Adipose-derived stem cells (ADSCs) can differentiate into vascular lineages and participate in vascular remodeling. Perivascular ADSCs (PV-ADSCs) draw attention because of their unique location. The heterogeneity of subcutaneous (SUB) and abdominal ADSCs were well addressed, but PV-ADSCs' heterogeneity has not been investigated. In this study, we applied single-cell analysis to compare SUB-ADSCs and PV-ADSCs regarding their subpopulations, functions, and cell fates. We uncovered four subpopulations of PV-ADSCs (Dpp4+, Col4a2+/Icam1+, Clec11a+/Cpe+, and Sult1e1+ cells), among which the Clec11a+ subpopulation potentially participated in and regulated PV-ADSC differentiation toward a smooth muscle cell (SMC) phenotype. Distinct characteristics between PV-ADSCs and SUB-ADSCs were revealed.

Platelet-Derived Growth Factor-Functionalized Scaffolds for the Recruitment of Synovial Mesenchymal Stem Cells for Osteochondral Repair

Cartilage regeneration is still a challenge for clinicians because of avascularity, denervation, load-bearing, synovial movement, and the paucity of endogenous repair cells. We constructed a multilayered osteochondral bionic scaffold and examined its repair capacity using a rabbit osteochondral defect model. The cartilage phase and interface layer of the scaffold were prepared by freeze-drying, whereas the bone phase of the scaffold was prepared by high-temperature sintering. The three-phase osteochondral bionic scaffold was formed by joining the hydroxyapatite (HAp) and silk fibroin (SF) scaffolds using the repeated freeze-thaw method. Different groups of scaffolds were implanted into the rabbit osteochondral defect model, and their repair capacities were assessed using imaging and histological analyses. The cartilage phase and the interface layer of the scaffold had a pore size of 110.13 ± 29.38 and 96.53 ± 33.72 μm, respectively. All generated scaffolds exhibited a honeycomb porous structure. The polydopamine- (PDA-) modified scaffold released platelet-derived growth factor (PDGF) for 4 weeks continuously, reaching a cumulative release of 71.74 ± 5.38%. Synovial mesenchymal stem cells (SMSCs) adhered well to all scaffolds, but demonstrated the strongest proliferation ability in the HSPP (HAp-Silk-PDA-PDGF) group. Following scaffold-induced chondrogenic differentiation, SMSCs produced much chondrocyte extracellular matrix (ECM). In in vivo experiments, the HSPP group exhibited a significantly higher gross tissue morphology score and achieved cartilage regeneration at an earlier stage and a significantly better repair process compared with the other groups (P < 0.05). Histological analysis revealed that the new cartilage tissue in the experimental group had a better shape and almost filled the defect area, whereas the scaffold was nearly completely degraded. The new cartilage was effectively fused with the surrounding normal cartilage, and a substantial amount of chondrocyte ECM was formed. The SF/HAp three-layer osteochondral bionic scaffold exhibited favorable pore size, porosity, and drug sustained-release properties. It demonstrated good biocompatibility in vitro and encouraging repair effect at osteochondral defect site in vivo, thereby expected to enabling the repair and regeneration of osteochondral damage.

Infrapatellar Fat Pads-Derived Stem Cell Is a Favorable Cell Source for Articular Cartilage Tissue Engineering: An In Vitro and Ex Vivo Study Based on 3D Organized Self-Assembled Biomimetic Scaffold

OBJECTIVE

Adipose tissue-derived stem cells (ASCs) are a promising source of cells for articular cartilage regeneration. However, ASCs isolated from different adipose tissue depots have heterogeneous cell characterizations and differentiation potential when cultured in 3-dimensional (3D) niches.

DESIGN

We compared the chondrogenicity of ASCs isolated from infrapatellar fat pads (IPFPs) and subcutaneous fat pads (SCFPs) in 3D gelatin-based biomimetic matrix.

RESULTS

The IPFP-ASC-differentiated chondrocytes had higher ACAN, COL2A1, COL10, SOX6, SOX9, ChM-1, and MIA-3 mRNA levels and lower COL1A1 and VEGF levels than the SCFP-ASCs in 3D matrix. The difference in mRNA profile may have contributed to activation of the Akt, p38, RhoA, and JNK signaling pathways in the IPFP-ASCs. The chondrocytes differentiated from IPFP-ASCs had pronounced glycosaminoglycan and collagen type II production and a high chondroitin-6-sulfate/chondroitin-4-sulfate ratio with less polymerization of β-actin filaments. In an ex vivo mice model, magnetic resonance imaging revealed a shorter T2 relaxation time, indicating that more abundant extracellular matrix was secreted in the IPFP-ASC-matrix group. Histological examinations revealed that the IPFP-ASC matrix had higher chondrogenic efficacy of new cartilaginous tissue generation as evident in collagen type II and S-100 staining. Conclusion. ASCs isolated from IPFPs may be better candidates for cartilage regeneration, highlighting the translational potential of cartilage tissue engineering using the IPFP-ASC matrix technique.

Extracellular vesicle therapeutics from plasma and adipose tissue

Extracellular vesicles (EVs) are cell-released lipid-bilayer nanoparticles that contain biologically active cargo involved in physiological and pathological intercellular communication. In recent years, the therapeutic potential of EVs has been explored in various disease models. In particular, mesenchymal stromal cell-derived EVs have been shown to exert anti-inflammatory, anti-oxidant, anti-apoptotic, and pro-angiogenic properties in cardiovascular, metabolic and orthopedic conditions. However, a major drawback of EV-based therapeutics is scale-up issues due to extensive cell culture requirements and inefficient isolation protocols. An emerging alternative approach to time-consuming and costly cell culture expansion is to obtain therapeutic EVs directly from the body, for example, from plasma and adipose tissue. This review discusses isolation methods and therapeutic applications of plasma and adipose tissue-derived EVs, highlighting advantages and disadvantages compared to cell culture-derived ones.

Adipose-derived stromal cells for nonhealing wounds: Emerging opportunities and challenges

Wound healing complications affect thousands of people each year, thus constituting a profound economic and medical burden. Chronic wounds are a highly complex problem that usually affects elderly patients as well as patients with comorbidities such as diabetes, cancer (surgery, radiotherapy/chemotherapy) or autoimmune diseases. Currently available methods of their treatment are not fully effective, so new solutions are constantly being sought. Cell-based therapies seem to have great potential for use in stimulating wound healing. In recent years, much effort has been focused on characterizing of adipose-derived mesenchymal stromal cells (AD-MSCs) and evaluating their clinical use in regenerative medicine and other medical fields. These cells are easily obtained in large amounts from adipose tissue and show a high proregenerative potential, mainly through paracrine activities. In this review, the process of healing acute and nonhealing (chronic) wounds is detailed, with a special attention paid to the wounds of patients with diabetes and cancer. In addition, the methods and technical aspects of AD-MSCs isolation, culture and transplantation in chronic wounds are described, and the characteristics, genetic stability and role of AD-MSCs in wound healing are also summarized. The biological properties of AD-MSCs isolated from subcutaneous and visceral adipose tissue are compared. Additionally, methods to increase their therapeutic potential as well as factors that may affect their biological functions are summarized. Finally, their therapeutic potential in the treatment of diabetic and oncological wounds is also discussed.

Adipose Tissue-Derived Stem Cells: Immunomodulatory Effects and Therapeutic Potential

Adipose-derived stem cells (ASCs) can self-renew and differentiate along multiple cell lineages. ASCs are also potently anti-inflammatory due to their inherent ability to regulate the immune system by secreting anti-inflammatory cytokines and growth factors that play a crucial role in the pathology of many diseases, including multiple sclerosis, diabetes mellitus, Crohn's, SLE, and graft-versus-host disease. The immunomodulatory effects and mechanisms of action of ASCs on pathological conditions are reviewed here.

Are Stem Cells Derived from Synovium and Fat Pad Able to Treat Induced Knee Osteoarthritis in Rats?

Background

Osteoarthritis (OA) is a chronic disease and a significant cause of joint pain, tenderness, and limitation of motion. At present, no specific treatment is available, and mesenchymal stem cells (MSCs) have shown promising potentials in this regard. Herein, we aimed to evaluate the repairing potentials of stem cells derived from the synovium and fat pad in the treatment of OA.

Methods

Twenty-eight male rats (220 ± 20 g, aged 10-12 weeks), were randomly divided into four groups (n = 7): C1: nontreated group, C2: Hyalgan-treated group, E1: adipose tissue-derived stem cell-treated group, and E2: synovial membrane-based stem cell-treated group. Collagenase type II was injected into the left knee; after eight weeks, OA was developed. Then, stem cells were injected, and rats were followed for three months. Afterward, specimens and radiological images were investigated. p value ≤ 0.05 was set as statistically significant.

Results

Compared to the C1 group, the E1 and E2 groups showed significantly better results in all six pathological criteria as well as joint space width and osteophytes of medial tibial, medial femoral, and medial fabellar condyles (p ≤ 0.001). Similarly, compared to the C2 group, the E1 and E2 groups had better scores regarding surface, matrix, cell distribution, and cell population viability (p < 0.05). E2 showed considerably higher scores compared to C2 regarding subchondral bone and cartilage mineralization (p < 0.05). The joint space width was similar between the C2 and E groups.

Conclusion

Treatment of OA with MSCs, particularly synovial membrane-derived stem cells, not only prevented but also healed OA of the knee to some extent in comparison to the Hyalgan and nontreatment groups.

Multiple umbilical cord-derived MSCs administrations attenuate rat osteoarthritis progression via preserving articular cartilage superficial layer cells and inhibiting synovitis

Background/objectives

Articular cartilage erosion probably plays a substantial role in osteoarthritis (OA) initiation and development. Studies demonstrated that umbilical cord–derived mesenchymal stem cells (UCMSCs) could delay chondrocytes apoptosis and ameliorate OA progression in patients, but the detailed mechanisms are largely uncharacterised. In this study, we aimed to study the effects of UCMSCs on monosodium iodoacetate (MIA)–induced rat OA model, and explore the cellular mechanism of this effect.

Methods

Intra-articular injection of 0.3 ​mg MIA in 50 ​μL saline was performed on the left knee of the 200 ​g weight male Sprague-Dawley rat to induce rat knee OA. A single dose of 2.5 ​× ​10⁵ undifferentiated UCMSCs one day after MIA or three-time intra-articular injection of 2.5 ​× ​10⁵ UCMSCs on Days 1, 7 ​and 14 were given, respectively. Four weeks after MIA, joints were harvested and processed for paraffin sections. Safranine-O staining, haematoxylin and eosin staining ​and immunohistochemistry of MMP-13, ADAMTS-5, Col-2, CD68 ​and CD4 were performed to observe cartilage erosion and synovium. For in vitro ​studies, migration ability of cartilage superficial layer cells (SFCs) by UCMSCs were accessed by transwell assay. Furthermore, catabolism change of MIA-induced SFCs by UCMSCs was performed by real-rime polymerase chain reaction of Col-X and BCL-2 genes. CCK-8 assay was performed to check proliferation ability of SFCs by UCMSCs-conditioned media.

Result

In this study, we locally injected human UCMSCs, which is highly proliferative and noninvasively collectible, into MIA-induced rat knee OA. An important finding is on obviously ameliorated cartilage erosion and decreased OA Mankin score by repeated UCMSCs injection after MIA injection compared with single injection, both of which attenuated OA progression compared with vehicle. Interestingly, we observed significantly increased number of SFCs on the articular cartilage surface, probably related to elevated proliferation, mobilisation and inhibited catabolism marker: Col-X and BCL-2 gene expression of cultured SFCs by UCMSCs-conditioned media treatment in vitro. In addition to the change of unique SFCs, catabolism markers of ADAMTS-5 and MMP-13 were substantially upregulated in the whole cartilage layer chondrocytes as well. Strikingly, MIA-induced inflammatory cells infiltration, on both CD4+ Th cells and CD68+ macrophages, and hyperplasia of the synovium, which was alleviated by repeated UCMSCs injection.

Conclusion

Our study demonstrated a critical role of repeated UCMSCs dosing on preserving SFCs function, cartilage structure and inhibiting synovitis during OA progression, and thus provided mechanistic proof of evidence for the use of UCMSCs on OA patients in the future.

The translational potential of this article

UCMSCs are a relatively “young” stem cell, and noninvasively collectible. In our study, we clearly demonstrated that it could effectively delay OA progression, possibly through reserving SFCs function and inhibiting synovitis. Therefore, it could be a new promising therapeutic cell source for OA after further clinical trials.

The use of large animals to facilitate the process of MSC going from laboratory to patient-'bench to bedside'

Large animal models have been widely used to facilitate the translation of mesenchymal stem cells (MSC) from the laboratory to patient. MSC, with their multi-potent capacity, have been proposed to have therapeutic benefits in a number of pathological conditions. Laboratory studies allow the investigation of cellular and molecular interactions, while small animal models allow initial 'proof of concept' experiments. Large animals (dogs, pigs, sheep, goats and horses) are more similar physiologically and structurally to man. These models have allowed clinically relevant assessments of safety, efficacy and dosing of different MSC sources prior to clinical trials. In this review, we recapitulate the use of large animal models to facilitate the use of MSC to treat myocardial infarction-an example of one large animal model being considered the 'gold standard' for research and osteoarthritis-an example of the complexities of using different large animal models in a multifactorial disease. These examples show how large animals can provide a research platform that can be used to evaluate the value of cell-based therapies and facilitate the process of 'bench to bedside'.

Molecular Mechanisms Contributing to Mesenchymal Stromal Cell Aging

Mesenchymal stem/stromal cells (MSCs) are a reservoir for tissue homeostasis and repair that age during organismal aging. Beside the fundamental in vivo role of MSCs, they have also emerged in the last years as extremely promising therapeutic agents for a wide variety of clinical conditions. MSC use frequently requires in vitro expansion, thus exposing cells to replicative senescence. Aging of MSCs (both in vivo and in vitro) can affect not only their replicative potential, but also their properties, like immunomodulation and secretory profile, thus possibly compromising their therapeutic effect. It is therefore of critical importance to unveil the underlying mechanisms of MSC senescence and to define shared methods to assess MSC aging status. The present review will focus on current scientific knowledge about MSC aging mechanisms, control and effects, including possible anti-aging treatments.

Evolution of ASC Immunophenotypical Subsets During Expansion In Vitro

Adipose-derived stromal/stem cells (ASCs) are currently being considered for clinical use for a number of indications. In order to develop standardized clinical protocols, it is paramount to have a full characterization of the stem cell preparations. The surface marker expression of ASCs has previously been characterized in multiple studies. However, most of these studies have provided a cross-sectional description of ASCs in either earlier or later passages. In this study, we evaluate the dynamic changes of 15 different surface molecules during culture. Using multichromatic flow cytometry, ASCs from three different donors each in passages 1, 2, 4, 6, and 8 were analyzed for their co-expression of markers associated with mesenchymal stem cells, wound healing, immune regulation, ASC markers, and differentiation capacity, respectively. We confirmed that at an early stage, ASC displayed a high heterogeneity with a plethora of subpopulations, which by culturing became more homogeneous. After a few passages, virtually all ASCs expressed CD29, CD166 and CD201, in addition to canonical markers CD73, CD90, and CD105. However, even at passage 8, there were several predominant lineages that differed with respect to the expression of CD34, CD200 and CD271. Although the significance of remaining subpopulations still needs to be elucidated, our results underscore the necessity to fully characterize ASCs prior to clinical use.

The relationship between synovial inflammation, structural pathology, and pain in post-traumatic osteoarthritis: differential effect of stem cell and hyaluronan treatment

Background

Synovitis is implicated in the severity and progression of pain and structural pathology of osteoarthritis (OA). Increases in inflammatory or immune cell subpopulations including macrophages and lymphocytes have been reported in OA synovium, but how the particular subpopulations influence symptomatic or structural OA disease progression is unclear. Two therapies, hyaluronan (HA) and mesenchymal stem cells (MSCs), have demonstrated efficacy in some clinical settings: HA acting as device to improve joint function and provide pain relief, while MSCs may have immunomodulatory and disease-modifying effects. We used these agents to investigate whether changes in pain sensitization or structural damage were linked to modulation of the synovial inflammatory response in post-traumatic OA.

Methods

Skeletally mature C57BL6 male mice underwent medial-meniscal destabilisation (DMM) surgery followed by intra-articular injection of saline, a hyaluronan hexadecylamide derivative (Hymovis), bone marrow-derived stem cells (MSCs), or MSC + Hymovis. We quantified the progression of OA-related cartilage, subchondral bone and synovial histopathology, and associated pain sensitization (tactile allodynia). Synovial lymphocytes, monocyte/macrophages and their subpopulations were quantified by fluorescent-activated cell sorting (FACS), and the expression of key inflammatory mediators and catabolic enzyme genes quantified by real-time polymerase chain reaction (PCR).

Results

MSC but not Hymovis significantly reduced late-stage (12-week post-DMM) cartilage proteoglycan loss and structural damage. Allodynia was initially reduced by both treatments but significantly better at 8 and 12 weeks by Hymovis. Chondroprotection by MSCs was not associated with specific changes in synovial inflammatory cell populations but rather regulation of post-injury synovial Adamts4, Adamts5, Mmp3, and Mmp9 expression. Reduced acute post-injury allodynia with all treatments coincided with decreased synovial macrophage and T cell numbers, while longer-term effect on pain sensitization with Hymovis was associated with increased M2c macrophages.

Conclusions

This therapeutic study in mice demonstrated a poor correlation between cartilage, bone or synovium (histo)pathology, and pain sensitization. Changes in the specific synovial inflammatory cell subpopulations may be associated with chronic OA pain sensitization, and a novel target for symptomatic treatment.

Adipose-derived stem cells contribute to cardiovascular remodeling

Obesity is an independent risk factor for cardiovascular disease. Adipose tissue was initially thought to be involved in metabolism through paracrine. Recent researches discovered mesenchymal stem cells inside adipose tissue which could differentiate into vascular lineages in vitro and in vivo, participating vascular remodeling. However, there were few researches focusing on distinct characteristics and functions of adipose-derived stem cells (ADSCs) from different regions. This is the first comprehensive review demonstrating the variances of ADSCs from the perspective of their origins.

Influence of glucose and insulin in human adipogenic differentiation models with adipose-derived stem cells

Autologous fat grafting represents an attractive source for tissue engineering applications in the field of reconstructive medicine. However, in adipogenic differentiation protocols for human adipose-derived stem cells, the concentration of glucose and insulin varies considerably. With the intent to gain maximum tissue augmentation, we focused on the late phase of adipogenesis. In this study, we modified the differentiation protocol for adipose-derived stem cells by prolongation of the induction period and the application highly concentrated glucose and insulin. Human adipose-derived stem cells were isolated from subcutaneous depots and differentiated in a standard induction medium for the first two weeks, followed by two weeks with varying glucose and insulin concentrations. Morphological changes assessed using Oil-Red-O staining were examined for corresponding alterations in the expression of the adipogenic markers peroxisome proliferator-activated receptor gamma (PPARγ) and lipoprotein lipase (LPL). Furthermore, glucose and lactate levels in conditioned media were monitored over the period of differentiation. We found high-glucose media increasing the level of lipid accumulation and the size of single droplets whereas insulin significantly showed a dose-dependent negative effect on fat storage. However, whereas high glucose stimulated PPARγ transcription, expression levels in insulin-treated cells remained constant. Results permit assumptions that a high-glucose medium intensifies the degree of differentiation in mature adipocytes providing conditions to promote graft volume while we have identified highly concentrated insulin treatment as an inhibitor of lipid storage in the late adipogenic differentiation.

Contribution of adipocyte precursors in the phenotypic specificity of intra-articular adipose tissues in knee osteoarthritis patients

Background

Intra-articular adipose tissues (IAATs) are involved in osteoarthritis (OA) pathophysiology. We hypothesize that mesenchymal cells residing in IAATs may account for the specific inflammatory and metabolic patterns in OA patients.

Methods

Adipocyte precursors (preadipocytes and dedifferentiated fat cells (DFATc)) from IAATs (infrapatellar and suprapatellar fat pads) and autologous subcutaneous adipose tissues (SCATs) were isolated from knee OA patients. The ability of these precursors to differentiate into adipocytes was assessed by oil red O staining after 14 days of culture in adipogenic medium. The gene expression of adipocyte-related transcription factors (C/EBP-α and PPAR-γ) and development-related factors (EN1 and SFRP2) were analyzed. The inflammatory pattern was assessed by RT-qPCR and ELISA (interleukin 6 (IL-6), IL-8, Cox2, and prostaglandin E2 (PGE₂)) after a 24-h stimulation by IL-1β (1 ng/mL) and by conditioned medium from OA synovium.

Results

IAAT preadipocytes displayed a significantly higher ability to differentiate into adipocytes and expressed significantly more C/EBP-α mRNA than SCAT preadipocytes. IAAT preadipocytes expressed significantly less EN-1 and SFRP2 mRNA than SCAT preadipocytes. Unstimulated IAAT preadipocytes displayed a less inflammatory pattern (IL-6, IL-8, and Cox2/PGE₂) than SCAT preadipocytes. In contrast, the response of IAAT preadipocytes to an inflammatory stimulus (IL-1β and conditioned media of OA synovium) was exacerbated compared to that of SCAT preadipocytes. Similar results were obtained with DFATc.

Conclusion

IAAT adipocyte precursors from OA patients have a specific phenotype, which may account for the unique phenotype of OA IAATs. The exacerbated response of IAAT preadipocytes to inflammatory stimulation may contribute to OA pathophysiology.

Investigation of stemness and multipotency of equine adipose-derived mesenchymal stem cells (ASCs) from different fat sources in comparison with lipoma

BACKGROUND

Adipose tissue-derived mesenchymal stem cells (ASCs) offer a promising cell source for therapeutic applications in musculoskeletal disorders. The appropriate selection of ASCs from various fat depots for cell-based therapy is challenging. The present study aims to compare stemness and multipotency of ASCs derived from retroperitoneal (RP), subcutaneous (SC), and lipoma (LP) fat to assess their usefulness for clinical application.

METHODS

Equine ASCs from the three fat tissue sources were isolated and characterized. The cell viability, proliferation, and self-renewal were evaluated using MTT, sulforhodamine B, and colony forming unit (CFU) assays. Stem cell relative marker CD44, CD90, and CD105 and tumor marker CA9 and osteopontin (OPN) expression were quantified using RT-qPCR. Multipotency of ASCs for adipogenic, osteogenic, and chondrogenic differentiation was examined by quantifying Oil Red O and Alizarin Red S staining, alkaline phosphatase activity (ALP), and expression of differentiation relative markers. All data were statistically analyzed using ANOVA.

RESULTS

RP fat-derived ASCs showed a higher cell proliferation rate compared to SC and LP derived cells. In contrast, ASCs from lipoma displayed a lower proliferation rate and impaired CFU capacities. The expression of CD44, CD90, and CD105 was upregulated in RP and SC derived cells but not in LP cells. RP fat-derived cells displayed a higher adipogenic potential compared to SC and LP cells. Although ASCs from all fat sources showed enhanced ALP activity following osteogenic differentiation, SC fat-derived cells revealed upregulated ALP and bone morphogenetic protein-2 expression together with a higher calcium deposition. We found an enhanced chondrogenic potency of RP and SC fat-derived cells as shown by Alcian blue staining and upregulation of aggrecan (Aggre), cartilage oligomeric matrix protein precursor (COMP), and collagen 2a1 (Col2a1) expression compared to LP. The expression of OPN and CA9 was exclusively upregulated in the ASCs of LP.

CONCLUSIONS

The results provide evidence of variation in ASC performance not only between normal fat depots but also compared to LP cells which suggest a different molecular regulation controlling the cell fate. These data provided are useful when considering a source for cell replacement therapy in equine veterinary medicine.

Subcutaneous and Visceral Adipose-Derived Mesenchymal Stem Cells: Commonality and Diversity

Adipose-derived mesenchymal stem cells (ASCs) are considered to be a useful tool for regenerative medicine, owing to their capabilities in differentiation, self-renewal, and immunomodulation. These cells have become a focus in the clinical setting due to their abundance and easy isolation. However, ASCs from different depots are not well characterized. Here, we analyzed the functional similarities and differences of subcutaneous and visceral ASCs. Subcutaneous ASCs have an extraordinarily directed mode of motility and a highly dynamic focal adhesion turnover, even though they share similar surface markers, whereas visceral ASCs move in an undirected random pattern with more stable focal adhesions. Visceral ASCs have a higher potential to differentiate into adipogenic and osteogenic cells when compared to subcutaneous ASCs. In line with these observations, visceral ASCs demonstrate a more active sonic hedgehog pathway that is linked to a high expression of cilia/differentiation related genes. Moreover, visceral ASCs secrete higher levels of inflammatory cytokines interleukin-6, interleukin-8, and tumor necrosis factor α relative to subcutaneous ASCs. These findings highlight, that both ASC subpopulations share multiple cellular features, but significantly differ in their functions. The functional diversity of ASCs depends on their origin, cellular context and surrounding microenvironment within adipose tissues. The data provide important insight into the biology of ASCs, which might be useful in choosing the adequate ASC subpopulation for regenerative therapies.

Polyamine supplementation reduces DNA damage in adipose stem cells cultured in 3-D

According to previous research, natural polyamines exert a role in regulating cell committment and differentiation from stemness during skeletal development. In order to assess whether distinct polyamine patterns are associated with different skeletal cell types, primary cultures of stem cells, chondrocytes or osteoblasts were dedicated for HPLC analysis of intracellular polyamines. Spermine (SPM) and Spermidine (SPD) levels were higher in adipose derived stem cells (ASC) compared to mature skeletal cells, i.e. chondrocytes and osteoblasts, confirming the connection of polyamine content with stemness. To establish whether polyamines can protect ASC against oxidative DNA damage in a 3-D differentiation model, the level of γH2AX was measured by western blot, and found to correlate with age and BMI of patients. Addition of either polyamine to ASC was able to hinder DNA damage in the low micromolecular range, with marked reduction of γH2AX level at 10 µM SPM and 5 µM SPD. Molecular analysis of the mechanisms that might underlie the protective effect of polyamine supplementation evidences a possible involvement of autophagy. Altogether, these results support the idea that polyamines are able to manage both stem cell differentiation and cell oxidative damage, and therefore represent appealing tools for regenerative and cell based applications.

Heterogeneity in Adipose Stem Cells

Adipose stem cells (ASCs) are the basis of procedures intended for tissue regeneration. These cells are heterogeneous, owing to various factors, including the donor age, sex, body mass index, and clinical condition; the isolation procedure (liposuction or fat excision); the place from where the cells were sampled (body site and depth of each adipose depot); culture surface; type of medium (whether supplemented with fetal bovine serum or xeno-free), that affect the principal phenotypic features of ASCs. The features related to ASCs heterogeneity are relevant for the success of therapeutic procedures; these features include proliferation capacity, differentiation potential, immunophenotype, and the secretome. These are important characteristics for the success of regenerative tissue engineering, not only because of their effects upon the reconstruction and healing exerted by ASCs themselves, but also because of the paracrine signaling of ASCs and its impact on recipient tissues. Knowledge of sources of heterogeneity will be helpful in the standardization of ASCs-based procedures. New avenues of research could include evaluation of the effects of the use of more homo1geneous ASCs for specific purposes, the study of ASCs-recipient interactions in heterologous cell transplantation, and the characterization of epigenetic changes in ASCs, as well as investigations of the effect of the metabolome upon ASCs behavior in culture.

Bone Marrow-Derived and Adipose-Derived Mesenchymal Stem Cell Therapy in Primary Knee Osteoarthritis: A Narrative Review

Regenerative medicine in the context of musculoskeletal injury is a broad term that offers potential therapeutic solutions to restore or repair damaged tissue. The current focus in recent literature and clinical practice has been on cell based therapy. In particular, much attention has been centered on autologous bone marrow concentrate and adipose-derived mesenchymal stem cells (MSCs) for cartilage and tendon disorders. This article provides an overview of MSC-derived therapy and offers a comprehensive review of adipose- and bone marrow-derived MSC therapy in primary knee osteoarthritis. LEVEL OF EVIDENCE: IV.

Single-Cell Gene Expression Analysis and Evaluation of the Therapeutic Function of Murine Adipose-Derived Stromal Cells (ASCs) from the Subcutaneous and Visceral Compartment

Introduction

Adipose-derived stromal cells (ASCs) are a promising resource for wound healing and tissue regeneration because of their multipotent properties and cytokine secretion. ASCs are typically isolated from the subcutaneous fat compartment, but can also be obtained from visceral adipose tissue. The data on their equivalence diverges. The present study analyzes the cell-specific gene expression profiles and functional differences of ASCs derived from the subcutaneous (S-ASCs) and the visceral (V-ASCs) compartment.

Material and Methods

Subcutaneous and visceral ASCs were obtained from mouse inguinal fat and omentum. The transcriptional profiles of the ASCs were compared on single-cell level. S-ASCs and V-ASCs were then compared in a murine wound healing model to evaluate their regenerative functionality.

Results

On a single-cell level, S-ASCs and V-ASCs displayed distinct transcriptional profiles. Specifically, significant differences were detected in genes associated with neoangiogenesis and tissue remodeling (for example, Ccl2, Hif1α, Fgf7, and Igf). In addition, a different subpopulation ecology could be identified employing a cluster model. Nevertheless, both S-ASCs and V-ASCs induced accelerated healing rates and neoangiogenesis in a mouse wound healing model.

Conclusion

With similar therapeutic potential in vivo, the significantly different gene expression patterns of ASCs from the subcutaneous and visceral compartments suggest different signaling pathways underlying their efficacy. This study clearly demonstrates that review of transcriptional results in vivo is advisable to confirm the tentative effect of cell therapies.

Platelet-rich Plasma and Mesenchymal Stem Cells: Exciting, But … are we there Yet?

Joint conditions incapacitate free movement driving to a sedentary lifestyle, a major risk factor for chronic diseases. Regenerative procedures, involving the use of mesenchymal stem/stromal cells along with platelet-rich plasma (PRP), can help patients with these conditions. We describe the main characteristics of cellular products (bone marrow concentrate, stromal vascular fraction of adipose tissue, and mesenchymal stem/stromal cells derived from these tissues), and the potential benefits of combination with PRP in 3 scenarios: PRP lysates used during laboratory cell expansion; PRP to prime cellular products or the host tissue before cell implantation; PRP used as a vehicle for cell transplantation and to provide trophic signals. Clinical studies exploring the benefits of combination products are limited to case series and few controlled studies, involving either arthroscopy or percutaneous injections. Combination products are making their way to clinics but further experimental and clinical research is needed to establish protocols and indications.

Intra-articular injection of mesenchymal stem cells in treating knee osteoarthritis: a systematic review of animal studies

PURPOSE

Mesenchymal stem cells (MSCs) injection has emerged as a novel treatment for knee osteoarthritis (KOA) but with inconsistent results in the experimental studies. Thus, the purpose of the present study is to evaluate the preclinical animal studies of MSCs injection for KOA and to determine the evidence for a role for MSCs in further clinical trials.

METHODS

A systematic search of KOA animal studies published through Aug 2017 was conducted using the PubMed, Embase and Web of science. Criteria for eligibility were animal studies assessing the therapeutic effects of MSCs intra-articular injection to animals with KOA. The methodological quality of included studies was assessed by the SYRCLE tool for assessing risk of bias in animal intervention studies. Descriptive synthesis was performed. Evidence quality was evaluated based on the Confidence in the Evidence from Reviews of Qualitative research (CERQual) tool.

RESULTS

Twenty-three KOA animal studies were eligible for inclusion. According to the SYRCLE's tool, all included studies had high risk of bias. Between-study heterogeneity was substantial. The included studies varied in terms of species, modeling methods, MSCs origin, treatment timing, injections frequency, transplantation type and dose of MSCs. The following outcomes, gross morphology, histological analysis, immunohistochemical analysis, radiological evaluation or behavior analysis, were reported in the primary studies. For all outcomes, the evidence quality was low or very low.

CONCLUSIONS

We do not have absolute confidence to recommend use MSCs injection for KOA clinical trials. Based on the internal and external validity of current animal studies, high quality experimental studies and efforts for effective translation from preclinical studies to clinical trials are still required.

Combating Osteoarthritis through Stem Cell Therapies by Rejuvenating Cartilage: A Review

Knee osteoarthritis (OA) is a chronic degenerative disorder which could be distinguished by erosion of articular cartilage, pain, stiffness, and crepitus. Not only aging-associated alterations but also the metabolic factors such as hyperglycemia, dyslipidemia, and obesity affect articular tissues and may initiate or exacerbate the OA. The poor self-healing ability of articular cartilage due to limited regeneration in chondrocytes further adversely affects the osteoarthritic microenvironment. Traditional and current surgical treatment procedures for OA are limited and incapable to reverse the damage of articular cartilage. To overcome these limitations, cell-based therapies are currently being employed to repair and regenerate the structure and function of articular tissues. These therapies not only depend upon source and type of stem cells but also on environmental conditions, growth factors, and chemical and mechanical stimuli. Recently, the pluripotent and various multipotent mesenchymal stem cells have been employed for OA therapy, due to their differentiation potential towards chondrogenic lineage. Additionally, the stem cells have also been supplemented with growth factors to achieve higher healing response in osteoarthritic cartilage. In this review, we summarized the current status of stem cell therapies in OA pathophysiology and also highlighted the potential areas of further research needed in regenerative medicine.

Articular and subcutaneous adipose tissues of rheumatoid arthritis patients represent equal sources of immunoregulatory mesenchymal stem cells

Adipose-derived mesenchymal stem cells (ASCs) have immunoregulatory properties, but their activity is dependent on signals provided by the local microenvironment. It is likely that highly inflammatory milieu of rheumatoid joint affects ASCs activity. To test this hypothesis, the function of rheumatoid ASCs derived from articular adipose tissue (AT-ASCs) and ASCs derived from subcutaneous adipose tissue (Sc-ASCs) has been analysed. Articular adipose tissue (infrapatellar fat pad) and subcutaneous adipose tissue (from the site of skin closure with sutures) were obtained from rheumatoid arthritis (RA) patients undergoing total knee joint replacement surgery. ASCs were isolated accordingly to the routinely applied procedure, expanded and treated or not with IFNγ and TNF (10 ng/ml). To evaluate immunomodulatory properties of AT- and Sc-ASCs, co-cultures with peripheral blood mononuclear cells (PBMCs) from healthy donors have been set. Proliferation of activated PBMCs (³H-thymidine incorporation method), secretion of IL-10 and IL-17A in co-culture supernatants (specific ELISA tests) and T regulatory FoxP3⁺ cells (Tregs) percentage have been evaluated (flow cytometry). Performed experiments demonstrated that ASCs from both sources have comparable properties. They suppress proliferation of activated PBMCs to the similar extent, induce IL-10 secretion by resting PBMCs and moderately induce generation of FoxP3⁺ Treg cells. Interestingly, both AT-ASCs and Sc-ASCs cause increase of IL-17A secretion by activated PBMCs as well as induce up-regulation of IL-6 concentration in co-culture supernatants. We demonstrated that AT-ASCs and Sc-ASCs obtained from RA patients possess similar immunomodulatory properties despite different localization and distinct cytokine milieu of tissue of origin. Our results indicate that ASCs derived from rheumatoid adipose tissues are not strongly immunosuppressive in vitro and that they may contribute to the pathogenesis of RA due to IL-17A secretion enhancement.