CARTILAGE DEFECTS AND OSTEOARTHRITIS
About 15% of the world's population is reportedly suffering from cartilage and joint damages such as degenerative arthritis and rheumatoid arthritis. As population aging progresses and as more young people start taking up active sports, the size of the problem is also growing.
The cartilage is a unique avascular, aneural tissue that does not regenerate easily once damaged. Chondral defects or damages to articular cartilages due to accidents, necrosis of subchondral bone tissue, or arthritis are some of the most common disorders nowadays. Various different types of treatments are currently in use, such as drug therapy, arthroscopy, and artificial joint surgery. However, they all fail to address the root cause. At present, complete treatment, or regeneration of damaged or defective cartilage is impossible and continuous drug administration or secondary surgeries are required in many cases. Even small cartilage lesions can severely affect the structure and function of articular cartilage and may predispose to the development of osteoarthritis (Alford and Cole, 2005). Osteoarthritis (OA) is by far one of the most common cause leading to adult orthopedic disability. Although it can occur in any synovial joint, it most commonly affects the knees, hips, and hands (Wolfstadt et al., 2015). OA affects all genders, ages and races, but is most common in elderly and obese individuals (Uth et al., 2014).
OA is a chronic, progressive, and irreversible degenerative joint disease, slowly induced in the bone, synovium and muscle by several processes including progressive cartilage deterioration, subchondral bone remodeling, loss of joint space, marginal osteophytosis, and loss of joint function (Wieland et al., 2005, Qi et al., 2012). OA generally develops progressively over several years, in response to the gradual failure of chondrocytes to repair damaged articular cartilage in synovial joints (Barry et al., 2013; Bijsma et al., 2011). Joints subjected to OA are unable to withstand normal mechanical stress owing to increased synthesis of tissue-destructive proteinases and apoptosis of chondrocytes, as well as generation of insufficient amounts of extracellular matrix (Bijsma et al., 2011).
Symptoms of the disease include neuropathic pain, stiffness, tenderness, depression, restless leg syndrome and sleep disorder (Kristjansson et al., 2014).
Also for OA, therapeutic tools and unconventional therapeutic methods, such as physical surgery for regeneration of damaged osteocytes, are lacking: conventional OA treatments (acetaminophen, NSAID and opiod analgesics) often result in complications such as limited activity and cannot slow or arrest OA progression. They rather help relieve pain and stiffness and maintain functional status. Surgery (arthroscopy, cartilage repair, marrow stimulation by microfracture, abrasion or drilling of the subchondral bone plate, total joint arthroplasty, and osteochondral grafting) is reserved as a last effort to manage OA symptoms in patients with refractory disease.
Because of these clinical features, treatment of OA requires innovative interventions such as non-stem cell based and stem cell based-therapies.

For first-generation non-stem cell therapy, cultured autologous chondrocyte implantation (ACI) has commonly been applied to treat cartilage defects, and encouraging clinical outcomes have been established (Counsel et al., 2015). ACI involves chondrocyte isolation from cartilage in non-weight bearing areas, expansion ex vivo, and implantation into defective areas in an injectable medium (Peterson et al., 2010) This first-generation therapy results in significant improvement in function, reduction in symptoms, and the regeneration of cartilage (Brittberg et al., 2010; Browne et al., 2005).
In recent years, this technique has been more widely applied as third-generation technique - owing to advancements that have improved efficiency - rather than injection as a cell suspension (Counsel et al., 2015). This advanced technique was named matrix-induced ACI (MACI) and involves the attachment or seeding of cultured autologous chondrocytes onto the surface of a biodegradable type I/III collagen membrane or the penetration of cultured autologous chondrocytes within a 3-dimensional scaffold or fleece (Marlovits et al., 2014). Some studies have reported positive outcomes following application of these techniques to knee and ankle lesions (Marlovits et al., 2014; Kon et al., 2011). The MACI requires less surgical time compared with ACI, develops less postoperative complications, and can be used to access difficult-to-reach defect sites (Marlovits et al., 2014).
However, these non-stem cell therapies require two invasive surgical procedures, one causing trauma in healthy articular cartilage, and have been limited to use for focal cartilage defects: generalized cartilage loss, as seen in OA, is not an indication for chondrocyte implantation (Brittberg et al., 1994). Also, this type of treatment cannot be applied to large lesions, nor is the efficacy satisfactory in patients over the age of 40 whose cellular activation levels are low. Loss of capacity to generate hyaline cartilage-like extracellular matrix due to chondrocyte de-differentiation and chondrocyte senescence is, therefore, a concern (Harrison et al., 2000). Moreover, autologous chondrocyte transplant is associated with morbidity of the cartilage sample removal, which needs intra-articular surgery, and with the limited tissue sample for culture. Chondrocytes in vitro expansion is necessary because relatively large quantities of healthy chondrocytes are required to fill up the defect site (Wu et al., 2013).


MESENCHYMAL STEM CELLS BASED APPROACH: EFFICACY
Techniques that cause multipotent adult mesenchymal stem cells (MSC) to differentiate into cells of the chondrogenic lineage have led to a variety of experimental strategies to investigate whether MSC - instead of chondrocytes- can be used for the regeneration and maintenance of articular cartilage.
Mesenchymal stem cells (MSC) are non-hematopoietic stromal cells that are able to differentiate into mesenchymal tissues such as bone, cartilage, muscle, ligament, tendon, and adipose, as well as in non-mesenchymal cell populations. MSC can be easily isolated from bone marrow, adipose tissue or other sources and can be rapidly expanded in culture. The International Society for Cellular Therapy has established minimal criteria for defining MSC, including the abilities to adhere to plastic under normal cell culture conditions, to express a set of cell surface antigens (CD105, CD73, and CD90) while not expressing antigens indicative of other cell lineages, and to differentiate into adipocytes, osteoblasts, and chondroblasts under specific conditions. Recent studies have shown that subcutaneous adipose tissue provides a clear advantage over other MSC sources due to the ease with which adipose tissue can be accessed (under local anesthesia and with minimum of patient discomfort) as well as to the ease of isolating stem cells from the harvested tissue. Moreover, stem cell frequency is significantly higher in adipose tissue than in bone marrow and the maintenance of the proliferating ability in culture seems to be superior in adipose-derived stem cells (ADSC) compared with bone marrow derived-MSC (Oedayrajsingh-Varma et al., 2006). ADSC have been shown to have immuno-suppressive and tissue regenerative capacities, to improve angiogenesis and prevent fibrosis. Moreover, ADSC can potently modulate immune responses, showing anti-inflammatory capacities, that can retard OA degeneration. The mechanisms underlying tissue regeneration and immune modulation by therapeutic doses of ADSC require further elucidation, particularly the extent to which the two processes intersect. The effect of ADSC involves trophic modulation by paracrine and autocrine activity; secretion of angiogenic, chemoattractant, and antiapoptotic factors; and specific anti-inflammatory effects through reduced T-cell activity and MHC suppression (Filomeno et al., 2012). Now it is largely recognized that, far from building new tissues at site of administration, ADSC exert immune-modulatory functions, secrete several bioactive molecules that inhibit apoptosis and stimulate angiogenesis and mitosis of tissue specific progenitors (Caplan et al., 2006; Park et al., 2010). Ultimately, thanks to ADSC extensive in vitro proliferative capacity, it is possible to produce the large numbers of cells needed for potential clinical applications, overcoming one the concerns of the expansion of chondrocytes for successful administration.
Therefore, MSC-based strategies should provide practical advantages for the patient with OA. These strategies include:
use of MSC as progenitor cells to engineer cartilage implants that can be used to repair chondral and osteochondral lesions, or use of MSC as trophic producers of bioactive factors to initiate endogenous regenerative activities in the OA joint (Noth et al., 2008).
In the future, targeted gene therapy might further enhance these activities of MSC.
Delivery of MSC might be attained by direct intra-articular injection or by graft of engineered constructs derived from cell seeded scaffolds; this latter approach could provide a three dimensional construct with mechanical properties that are congruous with the weight-bearing function of the joint.

Delivery of MSCs to Diseased Cartilage in Patients With Osteoarthritis. (A) Direct intra-articular injection of naive MSC. After harvest from an appropriate source, MSC can be delivered in suspension to the joint space, where they encounter all intra-articular tissues. (B) Matrix guided application of naive MSC. Restoration of the deep cartilage defects that occur in osteoarthritis might require MSC to be seeded into a biodegradable scaffold, which enables their controlled, local application to damaged areas of cartilage. From: Noth et al., 2008.
On these basisi, promising experimental and clinical data are beginning to emerge in support of the use of MSC for orthopaedics regenerative applications.
Several papers using animal models have been published.
In a recent paper, for example, intra-articular injection of scaffold-free Adipose Derived Stem Cells obtained from subcutaneous adipose tissue was shown as a viable approach for treating osteoarthritis in mature rabbits with unilateral anterior cruciate ligament transection. At 12 weeks after surgery, all knees showed radiological signs of osteoarthritis. At 12 weeks following surgery, the ADSC treated group was injected intra-articularly with a single dose of 1×106 cells suspended in 1 ml of medium. The control group received 1 ml of medium without cells and the sham-operated group received no treatment. The findings showed significant differences in the quality of cartilage between ADSC-injected group compared to control group, particularly at 20 weeks after surgery (Toghraie et al., 2012).
Desando and co-workers reported in Arthritis Research & Therapy that a single intra-articular delivery of ADSC attenuates progression of synovial activation and joint destruction in OA in an experimental rabbit model (Desando et al., 2013).

General opinion postulates that mesenchymal stem cells therapies for humans may have the potential to change the treatment of degenerative diseases and of severe traumatic injuries in the near future and initial clinical trials are promising for both safety and efficacy outcomes (Filomeno et al., 2012).

As stated before, recent MSC-based therapies for OA, in which a suspension of MSCs is injected, alone or in combination with other anti-inflammatory and pro-chondrogenic factors or with autologous platelet lysate (Centeno et al., 2011; Pak et al., 2013), into the osteoarthritic lesions have been developed (Whitworth et al., 2014).
Centeno et al. described six patients who received autologous MSC therapy for symptomatic carpometacarpal joint and hand OA and who were followed for 1 year post-treatment and matched with four untreated procedure candidates. Positive outcomes in the treatment group for both symptoms and function related to the OA were reported, compared with a reported worsening among the untreated controls. While these results should be interpreted with caution because of the small number of treated subjects and lack of placebo control and randomization, they set the base for further investigation of MSC therapy as an alternative to more invasive surgery in patients with OA of the hand (Centeno et al, 2014).
The same group had previously described a case study of a volunteer receiving a knee percutaneous injection of autologous ex vivo expanded MSC from bone marrow. At 24 weeks post-injection, the patient had statistically significant cartilage and meniscus growth on MRI, as well as increased range of motion and decreased modified VAS pain scores (Centeno et al., 2008).
Davatchi et al. assessed four patients aged 54, 55, 57, and 65 years with moderate to severe knee OA who received intra-articular injections of autologous bone marrow-derived MSC. After 6 months, walking time and pain scores improved in three patients. All patients showed improvement in the number of stairs they could climb and pain on VAS (Davatchi et al., 2011). A more recent follow up was published in 2015, and according to it, all parameters improved in transplant knees at 6 months (walking time, stair climbing, gelling pain, patella crepitus, flection contracture and the visual analogue score on pain), gradually started to deteriorate. However, at 5 years they were still better than at baseline (Davatchi et al., 2015).
Wakitani and his group transplanted autologous culture-expanded bone marrow MSC into nine full-thickness articular cartilage defects of the patello-femoral joints (including two kissing lesions) in the knees of three patients. Histology of the first patient, 12 months after transplantation, revealed that the defect had been repaired with fibrocartilaginous tissue. MRI of the second patient, 1 year after transplantation, revealed complete coverage of the defect, suggesting the efficacy of this approach (Wakitani et al., 2007).
Emamedin and coworkers treated six female volunteers with bone marrow derived MSC. During a one-year follow-up period, no local or systemic adverse events were found. Pain, functional status of the knee, and walking distance tended to be improved up to six months post-injection, after which pain appeared to be slightly increased and patients' walking abilities slightly decreased. Comparison of magnetic resonance images (MRI) at baseline and six months post-stem cell injection displayed an increase in cartilage thickness, extension of the repair tissue over the subchondral bone and a considerable decrease in the size of edematous subchondral patches in three out of six patients (Emamedin et al., 2012).
The same efficacy was demonstrated in a recent study by Jo and coworkers who performed intra-articular injection of autologous adipose tissue derived MSC (ADSC) for knee osteoarthritis in 18 patients with osteoarthritis of the knee. The phase I study consists of three dose-escalation cohorts; the low-dose (1.0 x 107 cells), mid-dose (5.0 x 107), and high-dose (1.0 x 107) group with three patients each. The phase II included nine patients receiving the high-dose. The primary outcomes were the safety and the Western Ontario and McMaster Universities Osteoarthritis index (WOMAC) at 6 months. Secondary outcomes included clinical, radiological, arthroscopic, and histological evaluations. There was no treatment-related adverse event. The WOMAC score improved at 6 months after injection in the high-dose group. The size of cartilage defect decreased while the volume of cartilage increased in the medial femoral and tibial condyles of the high-dose group. Arthroscopy showed that the size of cartilage defect decreased in the medial femoral and medial tibial condyles of the high-dose group. Histology demonstrated thick, hyaline-like cartilage regeneration (Jo et al., 2014).
Noth et al. has suggested that the direct intra-articular injection of MSCs might be effective only in the early stages of OA, when the defect is restricted to the cartilage layer. Later-stage OA often involves the bony component of the joint, and the presence of scaffolds suitable for the regeneration of subchondral bone is also an important factor (Noth et al., 2008).
Therefore, MSC can be, alternatively, implanted with a scaffold or encapsulated to enhance cell retention and survival (Wolfstadt et al., 2015). As stated before, apart from the choice of the appropriate cell type (for example, chondrocytes vs stem cells), cell therapy for orthopedic regenerative medicine, often involves the use of vehicles to support cells and scaffolds, becoming a kind of tissue engineering therapy.
The paradigm of a tissue engineering therapy approach is a biodegradable scaffold seeded with the appropriate cell population and bioactive factors, such that the scaffold is progressively replaced by neotissue formed in situ, which is histologically and functionally normal. The scaffold must initially bear the full mechanical load, but this must soon be gradually transferred to the ingrowing tissue to ensure the mechanical stimuli on the cells necessary for them to differentiate and produce and organize the extra cellular matrix. Scaffolds can provide three-dimensional, environmental cues that can dictate cell attachment, morphology, migration, proliferation, differentiation, and the orientation of matrix assembly. A part of this process may take place ex vivo, in bioreactors.
These three dimensional environments for cells have proved to be necessary to achieve in vitro significant extracellular matrix production (Garvin et al., 2003), and are also likely to make part of any successful in vivo strategy. A related approach used electrospun fibers embedded in a hydrogel to form a composite scaffold, demonstrating that the proportion of fibers determines both the initial mechanical properties and the chondrogenic response of MSC during culture (Coburn et al., 2013).
Many synthetic scaffolds commonly used in cartilage repair are fabricated using α-hydroxyl polyesters, including polyglycolic acid, poly-L-lactic acid, the copolymer poly-D-L-lacticoglycolic acid, and poly-ε-caprolactone (Noth et al., 2002; Teroda et al., 2005). The topography and material properties of these scaffolds are important in their ability to support MSC differentiation. Native biomaterials, including collagen type I, hyaluronan, chitosan and alginate, present a more natural microenvironment for MSC than synthetic scaffolds do. Collagen type I hydrogels have several advantages: these matrices are biodegradable, can be metabolized by MSC via the action of endogenous collagenases, elicit minimal, if any, inflammation, and surround the MSC in three dimensions. Moreover, the material properties of collagen hydrogels are similar to those of hyaline cartilage.
CARTISTEM® is a commercial product made of allogenic, unrelated, MSC from umbilical cord blood, ex vivo cultured and combined with sodium hyaluronate. It is used for treatment of articular cartilage defects of the knee as a result of ageing, trauma, or degenerative diseases, in patients with focal, full-thickness grade 3-4 articular cartilage defects of the knee (See, NCT01041001 and NCT01733186 on www.clinicaltrials.gov for FDA-approved clinical trials with CARTISTEM®).
Wakitani et al. reported on the use of transplanted bone marrow-derived MSC seeded with collagen type I hydrogels to repair cartilage defects in human knees with OA. Twenty-four patients with knee OA and articular cartilage defects in the medial femoral condyle were treated with MSC-loaded collagen gels covered with autologous periosteum. Forty-two weeks after transplantation, the defects were covered with white soft tissue, and some hyaline cartilage-like tissue was observed. The arthroscopic and histological grading scores were better in the cell-transplanted group than in the cell-free control group (Wakitani et al., 2002).
The same group transplanted MSCs seeded within collagen type I hydrogels to repair isolated, full thickness, cartilage defects in humans (Wakitani et al. 2004). Two patients with a patellar defect were treated with collagen gels containing MSCs, which were covered with a periosteal flap. Fibrocartilaginous filling of the defects was found after 1 year, and both patients showed significantly improved clinical outcomes in their respective follow-up after 1, 4, and 5 years.
This protocol was used to treat another patient with a full thickness cartilage defect in the weight bearing area of the medial femoral condyle. The patient's clinical symptoms had improved significantly 1 year after surgery. Histologically, the defect was filled with a hyaline like type of cartilage tissue that stained positively with safranin O, which indicated that the transplanted MSCs had differentiated into chondrocytes (Kuroda et al., 2007).
A recent paper by Kim and coworkers sums up that overall clinical outcomes of MSC implantation for knee OA are encouraging. However, patient age and lesion size are important factors that affect clinical outcomes; thus, these may serve as a basis for preoperative surgical decisions. Cutoff points exist for the risk of clinical failure in patients older than 60 years and those with a lesion size larger than 6.0 cm2 (Kim et al., 2015).

On the basis of these data, the therapeutic use of MSC for the regeneration of cartilage in patients with OA is feasible since:
independent radiological, arthroscopic, and histological measures consistently demonstrated that it decreased articular cartilage defects;
MSC treatment improved function and pain of the treated joint, without adverse events;
transplanted MSC maintain articular cartilage phenotype without hypertrophy, ossification and fibrogenesis (Noth et al., 2008);
even if MSCs obtained from the patient with OA differ functionally from those of healthy individuals, in terms of their chondrogenic capacity and longevity (the proliferative, chondrogenic and adipogenic capacities of MSC obtained from patients with OA are reportedly reduced (Murphy et al., 2002), perhaps due to their exposure to elevated levels of proinflammatory cytokines and/or anti-inflammatory drugs), researchers and clinicians should note that sufficient numbers of MSC with adequate chondrogenic differentiation potential can be isolated from patients with OA, irrespective of their age or the etiology of their disease (Im et al., 2006; Kafienah et al., 2007; Scharsthul et al., 2007).

BIOLOGICAL SAFETY OF MESENCHYMAL STEM CELLS FOR THE TREATMENT OF CARTILAGE DEFECTS
In a randomized, double-blind, controlled study, the safety of the intra-articular injection of human MSC into the knee, the ability of MSC to promote meniscus regeneration following partial meniscectomy, and the effects of MSC on osteoarthritic changes in the knee were investigated (Vangsness et al., 2014). A total of fifty-five patients were randomized to one of three treatment groups: Group A, in which patients received an injection of 50 × 10⁶ allogeneic mesenchymal stem cells; Group B, 150 × 10⁶ allogeneic mesenchymal stem cells; and the control group, a sodium hyaluronate (hyaluronic acid/hyaluronan) vehicle control. Clinical outcomes were measured at intervals through two years and included MRI. No ectopic tissue formation or clinically important safety issues were identified. There was significantly increased meniscal volume (defined a priori as a 15% threshold) determined by quantitative MRI in 24% of patients in Group A and 6% in Group B at twelve months post meniscectomy.
Absence of adverse events was confirmed also by Centeno and coworkers, who treated two groups of patients for various orthopedic conditions with culture-expanded, autologous, bone marrow-derived MSCs (group 1: n=50; group 2: n=290). Cells were cultured in monolayer culture flasks using an autologous platelet lysate technique and re-injected into peripheral joints or into intervertebral discs with use of c-arm fluoroscopy. Using both intensive high field MRI tracking and complications surveillance in 339 patients, no neoplastic complications were detected at any stem cell re-implantation site (mean follow up 435 ± 261 days) (Centeno et al., 2011).

These findings are consistent with other published reports (Pak et al., 2013) that show no evidence of malignant transformation in vivo, following implantation of MSC for orthopedic use.
In 2011, Wakitani published a retrospective paper in which 41 patients treated with autologous bone-marrow MSC to repair articular cartilage, between 1998 and 2008, were checked for tumors or infections between 5 and 137 months (average 75) of follow up: no abnormalities were found, confirming again the biological safety of the procedure (Wakitani et al., 2011).
Analogously, even if tumorigenic potential is especially worrisome, to date, any studies suggesting that ADSC have this ability are either inconclusive or have been retracted (Rubio et al., 2005; De la Fuente et al., 2010).
In a recent study culture-expanded human-derived ADSC were applied to immunosuppressed mice. At one year, animals were no different in weight nor life span from controls and showed no signs of tumorigenesis (MacIsaac et al., 2011).

FDA-APPROVED CLINICAL TRIALS ADMINISTERING ADSC FOR ORTHOPEDIC REGENERATION
ADSC have been approved by FDA for the conduction of more than 100 clinical trials for a variety of clinical conditions, ranging from dermo-aesthetics applications to severe diseases (www.clinicaltrial.gov). These are Phase I, Phase II and Phase III trials.
Since aims of Phase III trials are to confirm effectiveness, to monitor side effects, to compare it to commonly used treatments and collect information that will allow the experimental drug or treatment to be used safely, their approval means that – as we stated in the section before - the treatment’s overall safety has already been evaluated and that the use of these cells is generally regarded as safe.
Below is a selection of FDA-approved clinical trials aiming at assessing ADSC safety and efficacy in orthopedic regeneration (in particular, for osteoarthritis and cartilage defects):

1. NCT02090140: Microfracture versus Adipose Derived Stem Cells for the treatment of articular cartilage defects, sponsored by Standford University.
The purpose of this study is to compare two biologic methods for the treatment of articular cartilage defects in the knee. The first method, microfracture, is the standard of care and is routinely used to recruit cells from the subchondral bone marrow to the site of cartilage loss. The second method is the application of ADSC (isolated by arthroscopic resection of the infrapatellar fat pad) to the defect site. In theory, ADSC on a collagen scaffold should enable the delivery of more specific progenitor cells to the site of injury, resulting in better regeneration and integration of articular cartilage at the site of a defect as compared to the microfracture method. For outcomes measurement, the Knee Osteoarthritis Outcome Score (KOOS), a standard outcome questionnaire for the assessment of health-related quality of life, will be completed and cartilage composition will be assessed, 6, 12 and 24 months post-operatively, by means of a MRI scan.

2. NCT01947348: Safety and Clinical Effectiveness of A3 SVF in osteoarthritis, sponsored by Institute of Regenerative and Cellular Medicine.
To purpose of this prospective, non-randomized, clinical study is to determine if treatment with A3 (autologous, adipose, adult) SVF has an effect on pain and inflammation associated with osteoarthritis. Patients will be treated for osteoarthritis due to degeneration or chronic injury. They will be given autologous SVF extract derived by the A3 method mixed with activated platelets from a PRP (platelet rich plasma) preparation as direct injections to the effected joints. Outcomes will be tracked with WOMAC (Western Ontario and McMaster Universities Arthritis Index), AUSCAN (Australian Hand Osteoarthritis Index) scores, and a general blood panel in order to evaluate systemic effects.

3. NCT02357485: ADSC injections for pain management of osteoarthritis in the human knee joint, sponsored by Peter Fodor, Plastic Surgery Education and Research Foundation.
This safety and feasibility study used autologous ADSC, the stromal vascular fraction (SVF), to treat 8 osteoarthritic (OA) knees in 6 patients of grade I to III (K-L scale) with initial pain of 4 or greater on a 10 point scale, under IRB approved protocol. Evaluation of the safety of intra-articular injection of the stromal vascular fraction cells was the primary objective of the study. Adipose-derived stromal vascular cells were obtained through enzymatic disaggregation of lipoaspirate, resuspended in 3 ml of Lactated Ringer's Solution, and injected directly into the intra-articular space with a mean of 12 million viable nucleated SVF cells per knee.

4. NCT02219113: Effectiveness and safety of autologous ADRC for treatment of degenerative damage of knee articular cartilage, sponsored by Burnasyan Federal Medical Biophysical Center
Autologous adipose-derived regenerative cells (ADRC) extracted using Celution 800/CRS System (Cytori Therapeutics Inc) from a portion of the fat harvested from the patient's front abdominal wall are administered one-time intra-articularly. This is a single arm study with no control. All patients enrolled (suffering from degenerative damage of the knee articular cartilage) will receive cell therapy. Safety will be assessed as lack of adverse events and efficacy by monitoring of quality of life, knee pain intensity and changes in the knee joint function and structure (X-ray, MRI, ultrasonography).

5. NCT01585857: ADIPOA - Clinical study, sponsored by University Hospital, Montpellier.
This is a phase I, prospective, bi-centric, single-arm, open-label, dose-escalating clinical trial designed to evaluate the safety of a single intra-articular injection of autologous ADSC in the treatment of severe osteoarthritis of the knee joint on patients with moderate or severe osteoarthritis through record of serious adverse events. Secondary outcome is the study of the efficacy of a single injection of ADSC in patients with moderate or severe osteoarthritis of the knee.
The study evaluates safety and efficacy of ADSC in three different groups receiving, respectively, 2x106 ADSC as intra-articular injection (5 ml), 10x106 ADSC as intra-articular injection (5 ml), and 50 x 106 ADSC intra-articular injection (5 ml).

6. NCT02162693: Clinical trial of autologous Adipose Tissue-Derived Mesenchymal Progenitor Cells (MPCs) therapy for knee osteoarthritis, sponsored by Cellular Biomedicine Group Ltd.
Human adipose-derived mesenchymal progenitor cells (haMPCs) are obtained through a series of procedures: firstly, the fresh adipose tissue is digested with collagenase, filtered, centrifuged and then discard mature adipose cells to obtain adipose tissue-derived nuclear cells also called stromal vascular fraction cells (SVF). In the end, haMPCs are prepared after being purified and amplified to P2-P5 and are administered intra-articularly.

7. NCT01399749: Autologous mesenchymal stem cells versus chondrocytes for the repair of chondral knee defects (ASCROD), sponsored by Fundacion para la Investigacion Biomedica del Hospital Universitario la Paz.
The objective of our study is to compare the safety and effectiveness of the use of autologous cultured ADSC versus cultured autologous chondrocytes for the treatment of chondral knee lesions. Two groups will be treated: group 1 will receive implantation of autologous ADSC, 1 million per cm² lesion, covered by autologous periosteal membrane and group 2 will receive implantation of autologous chondrocytes, 1 million per cm² lesion, covered by autologous periosteal membrane. Primary outcome measures is the hyaline cartilage production for chondral knee lesions repair while secondary outcome measure will be a clinical, functional, histological and radiological evaluation. Systemic and local adverse events will also be assessed, especially if attributable to the implanted cells, in case of acute inflammatory events or of increase of pain.

8. NCT02241408: Outcomes data of Adipose Stem Cells to treat osteoarthritis, sponsored by StemGenex.
The purpose of this study is to determine the impact that the treatment with a cellular concentrate derived from an individual's own fat, known as the stromal vascular fraction (SVF), has on joint pain and functionality in people with osteoarthritis (OA). SVF contains components with "regenerative" properties, including stem cells that have shown promise for ameliorating specific disease conditions. This study is designed to evaluate joint pain and functionality changes in individuals with OA for up to 12 months following SVF treatment.

9. NCT01300598: Autologous adipose tissue derived mesenchymal stem cells transplantation in patient with degenerative arthritis, sponsored by RNL Bio Company Ltd.
The purpose of this study is to investigate the efficacy and safety of autologous transplantation of ADSC in patient with degenerative arthritis. It is a Phase I/ Phase II trial administering ADSC at three doses (1x107 cells/3ml, 5x107 cells/3ml, 1x108 cells/3ml) through intra-articular infusion. Primary outcome measures will be the assessment of the overall safety of RNL-JointStem® carrier using physical examinations, vital signs, treatment emergent adverse events (TEAEs), and the results of clinical lab tests: WOMAC (Western Ontario and McMaster Universities).

10. NCT01809769: Autologous adipose tissue derived mesenchymal progenitor cells therapy for patients with knee osteoarthritis, sponsored by Cellular Biomedicine Group Ltd.
This is a Phase I, prospective, placebo controlled, single-arm, dose-escalating clinical trial administering ADSC for knee osteoarthritis. Three injections each of 3 ml of ADSC will be administered. Time-points for intervention are: initial injection (1x106 cells/3ml); 1 months following initial injection (1x107 cells/3ml) and 3 months following initial injection (1x108 cells/3ml). This result in a total treatment duration of 3 months. Adipose (fat) tissue is removed by lipo-aspiration and is processed on-site to isolate the cells. The obtained cellular suspension is injected into the knee joint under ultrasound guidance. Primary outcome measures will be the WOMAC score (The Western Ontario and McMaster Universities Osteoarthritis Index). Secondary outcome measures will be recording of adverse events and serious adverse events.

11. NCT01885832: Safety and feasibility study of autologous stromal vascular fraction (SVF) cells for treatment of osteoarthritis, sponsored by Translational Biosciences.
The proposed study is a single center, unblinded, not randomized, phase I/II trial in which the patients will be treated with a single dose of autologous stromal vascular cells (SVF) isolated from 500 ml of adipose tissue extracted from the infraumbilical area. The cellular product will be administered via intra-articular injection into patients with moderate to severe osteoarthritis. Administration will be performed by injection into the synovial space. The dosing regimen will consist of two intra-articular injections of autologous SVF into the index knee. Total injection volume will be about 30 ml in two 15 ml aliquots via a 23 gauge needle inserted 1.5cm. deep into the intra-auricular space of the knee. The total number of SVF to be injected is 1x107 to 5x107. The purpose of this study will be to define the safety and efficacy of SVF therapy in improving joint function and the quality of life in patients with osteoarthritis of the knee.

12. NCT01856140: Treatment of tendon injury using mesenchymal stem cells (ALLO-ASC), sponsored by Seoul National University Hospital.
Main purpose of this Phase 0 study is to evaluate efficacy and safety of allogenic adipose-derived mesenchymal stem cells (ALLO-ASC) in treatment of tendon injury. ALLO-ASC will be administrated to the patients with lateral epicondylitis by ultrasonographic guided injection. Injection volume depends on the size of lesion on ultrasound examination. All injection will be done under ultrasound guidance. First the investigators will administrate 1 million cells/ml (Group 1 for 6 participants). After monitoring the safety of injection for 2 weeks (the investigators will use WHO recommendations for grading of acute and subacute toxic effects), the investigators can decide to increase the quantity as 10 million cells/ml (Group 2 for participants). The investigators will compare the efficacy difference as quantity increase.

13. NCT01739504: Autologous adipose-derived stromal cells delivered intra-articularly in patients with osteoarthritis, sponsored by Ageless Regenerative Institute.
This Phase I/II trial is an open-label, non-randomized, multi-center, patient sponsored study of Adipose-Derived Stem Cell (ASC) implantation performed intra-articularly to affected joints. The intent of this clinical study is to answer the questions: 1) Is the proposed treatment safe? and 2) Is treatment effective in improving the disease pathology of patients with diagnosed osteoarthritis? ASCs will be harvested from the patient's adipose-derived tissue. In addition, peripheral blood will be collected for isolation of platelet rich plasma. The adipose tissue is transferred to the laboratory for separation of the adipose tissue derived stem cells, which are then transferred for intra-articular administration in the patient's autologous platelet rich plasma.

14. NCT01663116: Cx611-0101, eASCs intravenous administration to refractory rheumatoid arthritis patients, sponsored by TiGenix S.A.U.
This Phase Ib/IIa study is designed as a multicenter, single blind, fixed dose escalation, with three treatment groups, controlled with placebo (randomization 3:1) whose target population are patients with rheumatoid arthritis refractory to at least two biologic. The primary objective of the study is to determine the safety, feasibility and tolerance, and to identify, if possible, the dose limiting toxicity (DLT) and the dose for future clinical trials on efficacy of the intravenous infusion of allogeneic adipose-derived mesenchymal cells eASCs for patients suffering rheumatoid arthritis (RA) under treatment with at least one non-biologic-Disease modifying antirheumatoid drug (DMARD) who have previously failed to treatment with at least two biologics. The secondary objective is to obtain information on the clinical and functional effects of the intravenous infusion of allogeneic eASCs in patients with RA and to explore pharmacodynamics parameters. 53 patients (i.e. patients having received at least one dose of study treatment) in three different cohorts are planned to be included in this clinical trial. Dose and intervals for the trial consist of the following active groups: a) first cohort: 1 million cells/kg administered at days 1, 8 and 15; b) second cohort: 2 million cells/kg administered at days 1, 8 and 15; c) third cohort: 4 million cells/kg administered at days 1, 8 and 15.

15. NCT01885819: Autologous adipose tissue stromal vascular fraction cells for rheumatoid arthritis, sponsored by Translational Biosciences.
Aim of this study is the assessment of the feasibility of non-expanded autologous adipose tissue derived stromal vascular fraction cells in Disease Modifying Anti-Rheumatic Drugs (DMARD)-resistant rheumatoid arthritis The proposed study will assess primarily safety and secondary efficacy endpoints of autologous stromal vascular fraction (SVF) cells administered to 20 patients with disease modifying anti-rheumatic drug (DMARD)-resistant Rheumatoid Arthritis (RA) who have been nonresponsive to at least one course of one DMARD selected from a group comprising of: gold salts, leflunomide, methotrexate, and hydroxychloroquine. The primary objective of safety will be defined as freedom from treatment associated adverse events for the period of one year. The secondary objective of efficacy will include evaluation at baseline and at months 1, 2, 3 and 6 of efficacy endpoints of CRP, ESR, anti-citrulline antibody, RF, quality of life questionnaire, 28-joint disease activity score (DAS28), European League against Rheumatism (EULAR) response criteria and immunological parameters.

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