Chondrogenic differentiation of human bone marrow-derived mesenchymal stem cells in a simulated osteochondral environment is hydrogel dependent.

Hydrogels pose interesting features for cartilage regeneration strategies, such as the option for injectability and in situ gelation resulting in optimal filling of defects. We aimed to study different hydrogels for their capability to support chondrogenesis of human bone marrow-derived mesenchymal stem cells (hBMSCs). hBMSCs were encapsulated in alginate, alginate with hyaluronic acid (alginate/HA), fibrin or thermoresponsive HA grafted with poly(N-isopropyl acrylamide) side-chains (HA-pNIPAM). Glycosaminoglycan production and cartilage-related gene expression were significantly higher in hBMSC-alginate and hBMSC-fibrin constructs than in the other constructs. Supplementation of alginate with HA was not beneficial. hBMSC-alginate, hBMSC-fibrin and hBMSC-HA-pNIPAM constructs were placed in simulated defects in osteochondral biopsies and cultured in vitro for 28 d. Biopsies containing hBMSC-alginate and hBMSC-fibrin were implanted subcutaneously in nude mice for 12 weeks. hBMSC-alginate constructs had significantly higher cartilage-related gene expression after 28 d of culture as well as significantly more safranin-O positive repair tissue after 12 weeks in vivo than hBMSC-fibrin constructs. Although initial experiments with hBMSC-hydrogel constructs suggested comparable results of hBMSC-alginate, hBMSC-fibrin and hBMSC-HA-pNIPAM constructs, culture in the osteochondral biopsy model in vitro as well as in vivo revealed differences, suggests that chondrogenesis of hBMSCs in an osteochondral environment is hydrogel-dependent.

Statins and fibrates do not affect development of spontaneous cartilage damage in STR/Ort mice.

OBJECTIVE: Since statins and fibrates are capable of improving the metabolic profile of patients as well as decreasing inflammation, they are considered as potential drugs for preventing osteoarthritis (OA). The goal of the present study was to investigate the effect of these drugs in the STR/Ort spontaneous OA mouse model. DESIGN: Male STR/Ort mice received control diet or control diet containing two different dosages of simvastatin or fenofibrate or a combination of both. Mice were euthanized after 16 weeks of treatment at the age of 24 weeks. Serum analysis for metabolic and inflammatory markers, histologic OA grading and micro computed tomography (µCT) analysis of subchondral bone plate were performed. RESULTS: Simvastatin treatment did not have a statistically significant effect on any of the measured parameters. Fenofibrate treated mice gained less body weight (BW) and had lower serum amyloid A (SAA) levels, but higher Interleukin (IL)-1α and MIP1α than other mice. Mice treated with 200 mg/kg BW/day fenofibrate had less subchondral bone plate volume than control, but no statistically significant reduction in cartilage damage. In the combination treatment group, BW and SAA were lower than control. Overall, bodyweight, synovium membrane cell layers and SAA levels correlated to subchondral bone plate changes and subchondral bone plate changes correlated to cartilage damage. CONCLUSIONS: Statins and fibrates did not affect development of cartilage damage in the STR/Ort spontaneous OA mouse model. Fenofibrates however, had an effect on BW, serum inflammation markers and subchondral bone plate morphology.

Symptomatic and chondroprotective treatment with collagen derivatives in osteoarthritis: a systematic review.

OBJECTIVE: Osteoarthritis (OA) is one of the most prevalent musculoskeletal diseases. Collagen derivatives are candidates for disease-modifying OA drugs. This group of derivatives can be divided into undenatured collagen (UC), gelatine and collagen hydrolysate (CH). Collagen derivatives are marketed as having direct chondroprotective action and reducing complaints of OA. This review summarizes the evidence for the effectiveness of symptomatic and chondroprotective treatment with collagen derivatives in patients with OA. METHODS: Eligible randomised controlled trials (RCTs) and quasi-RCTs were identified by searching PubMed, Embase and the Cochrane Central Register of Controlled Trials until November 2011. Methodological quality was assessed using methods of the Cochrane Back Review Group. RESULTS: Eight studies were identified: six on CH, two on gelatine, and one on UC. The pooled mean difference based on three studies for pain reduction measured with the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index comparing CH with placebo was -0.49 (95% CI -1.10-0.12). However, some studies report significant between-group differences in pain when measured with a visual analogical scale (VAS) or other instruments, or when CH is compared with glucosamine sulphate. For disability no significant between-group mean differences were found when comparing CH with placebo. Gelatine compared with placebo and with alternative therapies was superior for the outcome pain. UC compared with glucosamine+chondroitin showed no significant between-group differences for pain and disability. The most reported adverse events of collagen derivatives were mild to moderate gastro-intestinal complaints. The overall quality of evidence was moderate to very low. CONCLUSIONS: There is insufficient evidence to recommend the generalized use of CHs in daily practice for the treatment of patients with OA. More independent high-quality studies are needed to confirm the therapeutic effects of collagen derivatives on OA complaints.

Effect of glucosamine sulphate on joint space narrowing, pain and function in patients with hip osteoarthritis; subgroup analyses of a randomized controlled trial.

OBJECTIVE: Recently we reported that glucosamine sulphate (GS) did not have an effect on the symptoms and progression of primary care patients with hip osteoarthritis (OA). The aim of this present study was to investigate whether there are subgroups of patients with hip OA for whom GS might be an effective therapy. METHOD: We randomized 222 patients with hip OA that met one of the American College of Rheumatology criteria to either 1500 mg of oral GS or placebo once daily for 2 years. Subgroup analyses were predefined for radiographic severity (Kellgren & Lawrence (KL)=1 vs >or=2) and for type of OA (localised vs generalised). Additional exploratory subgroup analyses focused on groups based on pain level, pain medication use, baseline joint space width (JSW), and concomitant knee OA at baseline. Primary outcome measures were Western Ontario MacMaster Universities (WOMAC) pain and function scores over 24 months, and joint space narrowing (JSN) after 24 months. RESULTS: In the predefined subgroups based on radiographic severity and type of OA, the outcomes WOMAC pain, function and JSN were similar for the GS and placebo group. CONCLUSION: GS was not significantly better than placebo in reducing symptoms and progression of hip OA in subgroups of patients.

In vivo imaging of cartilage degeneration using microCT-arthrography.

OBJECTIVE: In vivo imaging of cartilage degeneration in small animal models is nowadays practically impossible. In the present study, we investigated the use of micro-computed tomography (microCT) in combination with a negatively charged ionic iodine dimer (ioxaglate) for in vivo assessment of cartilage degeneration in a small animal model. METHODS: Cartilage degeneration was induced in the right knee of rats by injection of mono-iodoacetate (MIA). We imaged the rat knees with ioxaglate enhanced microCT-arthrography at 4, 16 and 44 days after MIA injection. Subsequently, microCT-arthrographic findings were evaluated and compared with quantitative histology of the patellar cartilage. RESULTS: In vivo microCT-arthrography clearly detected cartilage degeneration in the rat knee-joints, in which the ioxaglate diffused into the degenerated cartilage layer. Higher microCT-attenuation values and smaller total volumes of the cartilage layer were detected at longer time periods after MIA injection, which is quantitatively confirmed by histology. CONCLUSION: In vivo microCT-arthrography is a valuable tool for detection of minor cartilage alterations and distinguishes different stages of cartilage degeneration in a small animal model. Since microCT, at the same time, also visualizes osteophyte formation and changes in the underlying subchondral bone structures, the technique will be very useful for longitudinal overall assessment of the development of (osteo)arthritis and to study interventions in small animal models.

Fibroblast growth factor-2 in serum-free medium is a potent mitogen and reduces dedifferentiation of human ear chondrocytes in monolayer culture.

The loss of the differentiated phenotype (dedifferentiation) during the expansion culture of donor chondrocytes remains a large problem in cartilage tissue engineering. Dedifferentiated chondrocytes produce other matrix components and therefore the tissue produced will be of less suitable quality. Previously, the addition of fibroblast growth factor-2 (FGF2) to a serum-containing medium (SCM) during expansion culture was shown to have positive effects on the phenotype of articular chondrocytes. In the present study, we focused on a more defined, serum-free medium (SFM), to expand chondrocytes in monolayer culture for the purpose of cartilage tissue engineering. Adult human ear chondrocytes were expanded in serum-free medium supplemented with 100 ng/ml FGF2. Expansion culture in a conventional serum-containing medium (10% FCS) served as control. The cell yield during expansion culture in serum-free medium with FGF2 was significantly higher compared to serum-containing medium. In addition, chondrocytes expanded in the serum-free medium with FGF2 expressed a more differentiated phenotype at the end of monolayer culture, as indicated by higher gene expression ratios of collagen type II to collagen type I and aggrecan to versican. Also, a higher gene expression of Sox9 was found. Next, suspension in alginate and subsequent culture in vitro or subcutaneous implantation in nude mice was used to evaluate the capacity of the chondrocytes, expanded in either medium, to re-express the differentiated phenotype (redifferentiation) and to form cartilage. The observed beneficial effects of the serum-free medium with FGF2 on the chondrocyte phenotype at the end of monolayer culture were sustained on both transcriptional and extracellular level throughout both redifferentiation methods.