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Type 2 diabetes mellitus (T2DM) is increasingly being recognized as an independent risk factor for the onset and progression of osteoarthritis (OA). Extensive studies have focused on the contribution of obesity (excessive mechanical stress), comorbidity frequently found in T2DM, to cartilage destruction during OA development. However, a little is known about how diabetes-related inflammation may affect the local cartilage in a diabetic objective. In the present study, we were able to establish a T2DM rat model using a combination of a low dose of streptozotocin with high-fat and high-sugar diet. Although the cartilage integrity was comparable between the control and T2DM groups, the expression of matrix metalloproteinases-13 (MMP-13) was significantly upregulated in T2DM, indicating the initiation of an early cascade of cartilage degeneration. In parallel, an obvious alteration of subchondral bone remodeling (inhibition of bone formation) was observed, as evidenced by the reduction of osterix-expressing positive cells. Moreover, we demonstrated that the expression of intercellular adhesion molecule-1 (ICAM-1) in the serum and synovium of T2DM rats was elevated, accompanied by an increase of synovitis score. We also noticed that the number of F4/80-positive macrophage cells was significantly increased in the T2DM group. Mechanistically, the expression of ICAM-1 in fibroblast-like synoviocytes can be triggered by glucose and interleukin-1β, which are the two important factors within the joint of T2DM. Given that MMP-13 expression was significantly upregulated in the T2DM cartilage, and that ICAM-1-mediated filtration of macrophage was associated with synovitis, we propose that ICAM-1 is essential for triggering a vicious cycle of inflammation within the joint, which together subsequently drivers the cartilage degradation.

Fat flap transplantation is frequently performed in patients suffering from soft tissue defects resulting from disease or trauma. This study explored the feasibility of constructing vascularized fat flaps using rabbit adipose-derived stem cells (rASCs) and collagen scaffolds in a rabbit model. We evaluated rASCs proliferation, paracrine function, adipogenesis, vascularization, and CD54 expression, with or without HIF-1α transfection in vitro and in vivo. We observed that adipogenic differentiation potential was greater in rASCs with high CD54 expression (CD54+rASCs) than in those with low expression (CD54-rASCs), both in vitro and in vivo. HIF-1α overexpression not only augmented this effect, but also enhanced cell proliferation and paracrine function in vitro. We also demonstrated that HIF-1α-transfected CD54+rASCs showed enhanced paracrine function and adipogenic capacity, and that paracrine function increases expression of angiogenesis-related markers. Thus, CD54+rASCs overexpressing HIF-1α enhanced large volume vascularized fat flap regeneration in rabbits, suggesting CD54 may be an ideal candidate marker for ASCs adipogenic differentiation.

Supplemental Digital Content is available in the text, It has been suggested that microRNA-9 (miR-9) is associated with the development of knee osteoarthritis (OA). This study was aimed to investigate the association between the mechanism of miR-9 targeting nuclear factor kappa-B1 (NF-κB1) and the proliferation and apoptosis of knee OA chondrocytes. Cartilage samples were collected from 25 patients with knee OA and 10 traumatic amputees, and another 15 OA rat models, together with 15 rats without knee OA lesions were also established. MiR-9 expressions in both knee OA cartilage and normal cartilage samples were detected using quantitative real-time PCR. The expressions of related genes (NF-κB1, IL-6, and MMP-13) in the two groups were also detected. Dual luciferase reporter gene assay was employed to examine the effect of miR-9 on the luciferase activity of NF-κB1 3′UTR. Knee OA chondrocytes were transfected with miR-9 mimics, miR-9 inhibitor, and NF-κB1 siRNA, respectively, and changes in cellular proliferation and apoptosis were detected via MTT assay and flow cytometric analysis, respectively. Western blotting assay was used to detect the expressions of NF-κB1, interleukin-6 (IL-6), and matrix metalloproteinase-13 (MMP-13). According to results from human OA samples and rat OA models, miR-9 was significantly downregulated in knee OA cartilage tissues compared with normal cartilage tissues (P