Purpose: Substance P (SP) release and binding to NK-1 produces pain transmission. Pain from arthritis is expressed as both tenderness and as loss of function. Different arthritis pain models express pain differently. This study evaluated the relationship of dorsal root ganglion (DRG) SP expression to pain using both measures of tenderness and function in 3 different models of arthritis pain. Neurotoxins (NT) that prevent release of SP, such as onabotulinum toxin (BoNT/A), and those that deplete SP, such as vanilloids (VAN), can produce analgesia in these models. We correlated effects on SP expression in the DRG with analgesic responses. Methods: C57/Bl6 male mice received intra-articular (IA) carrageenan, Complete Freund's Adjuvant (CFA) or Collagenase (COL) to produce acute inflammatory, chronic inflammatory or chronic noninflammatory arthritis respectively. IA therapies were given at appropriate intervals before examination. Twelve-week-old mice were examined after arthritis induction. Evoked (tenderness) and spontaneous (functional) pain was quantitated. DRGs were harvested for immunohistochemistry (IHC) after pain assessment. SP expression was measured as % DRG neurons expressing SP. Results: Both Evoked and Spontaneous pain in arthritic and naïve mice

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also automatically selected and applied to max-flow/min-cut algorithm in graph-cut based method to find the region. We calculated dice similarity coefficient (DSC), sensitivity and specificity of femoral and tibial cartilages for analysis. Results: The devised scheme was performed successfully on all test cases. The running machine specification was Windows 7 64bit (OS), Intel i7-2600K (CPU) and 16GB (RAM). The average computation time was about 30 minutes for the atlas building procedure and 2 hours for the local adjustment procedure. Figure 1 shows one result of this atlas building procedure. The left image corresponds to the ground truth segmentation result. The nine smaller images in the right panel represent selected results following the registration. The segmented regions are color labeled and overlaid onto the MR images for better visualization. Figure 2 illustrates one example of the local adjustment procedure. The left image corresponds to the merged atlas based result, while the right image shows the final result following the local adjustment procedure. The analytical performance metrics of our program are shown in table 1. Conclusion: A fully automatic segmentation scheme for knee cartilage from MR images was developed and the performance of the scheme was evaluated with 40 test cases. The preliminary result is promising. We are continuing to further refine the algorithm and improve the performance.

Purpose: Mesenchymal stem cells (MSCs) enhance regeneration when locally delivered in pre-clinical models of osteoarthritis (OA). Their mechanism of action, however, is still poorly understood. Preliminary data show low engraftment of GFP-expressing syngeneic MSCs in mouse knee joints, consistent with published data using molecular techniques. We hypothesise that implanted cells undergo apoptosis or cell death. There is growing evidence that apoptotic MSCs exert an antiinflammatory effect, by release of immunosuppressive cytokines and, indirectly, through phagocytes. This study aims to investigate the immunomodulatory potential of apoptotic MSCs in vitro, to correlate with in vitro results in a mouse model of OA. Methods: Collagenase-induced OA (CIOA) was performed on C57BL/6 mice and 2x10 5 GFP-expressing MSCs were intra-articularly (IA)-delivered in the animals. Knee joints were harvested 3 days post-IA-injection and digested into a single cell suspension before sorting implanted GFPþ MSCs using the BD FACS Aria II. Retrieved cells were expanded in culture and characterised by cell surface markers and differentiation. Their immunosuppressive capacity was tested in vitro on murine lymphocytes and bone marrow-derived macrophages (BMDM). Apoptosis of MSCs was induced in vitro by treatment with Staurosporine (STS), while necrosis was produced by heat treatment (90 C, 5 min). Apoptosis was validated by pre-treating the cells with the pancaspase inhibitor Q-VD-OPH. All treatments were evaluated by flow cytometry using anti-Annexin V/Sytox Blue staining; activation of caspases was measured by FLICA assays. Apoptotic MSCs were co-cultured with activated murine splenocytes for 3 days. Suppression of proliferation was measured by quantification of Cell Trace Violet and expression of CD25. Conditioned media from apoptotic and necrotic MSCs were tested on LPS-activated BMDM and expression of pro-and anti-inflammatory molecules was assessed by ELISA (IL-6, IL-10, TGF-b, PGE2) and Griess assay (NO). Results: On average, 1.63% of the injected cells were successfully retrieved by cell sorting, with 82.1% sample purity. Sorted cells proliferated in culture retaining MSC-like morphology, expression of cell surface markers and differentiation potential. Retrieved cells have an increased immunosuppressive potential as observed on activated BMDMs and lymphocytes. STS successfully induced apoptosis, with activation of Caspase 3/7; Q-VD-OPH completely inhibited apoptosis, confirming the involvement of caspases. Necrotic, but most strikingly apoptotic MSCs, significantly prevented the proliferation and activation of murine splenocytes (Fig. 1). BMDM were also induced towards an anti-inflammatory phenotype, as shown by their secretory profile. Conclusions: MSCs can be administered and retrieved from murine knee joints and remain viable for characterisation. Retrieval yield is low, consistent with previous studies. IA-injected MSCs may contribute to local modulation of joint inflammation. Engrafted MSCs retrieved from the OA joint were ...

the secondary outcomes ICOAP intermittent and constant pain (statistically significant and clinically relevant differences between the groups at 3 months but not at 12 months follow-up), but not for the other outcomes (no differences between the groups at 3 months and at 12 months follow-up). No adverse events were reported during the study. Conclusions: At 3 months follow-up there was a statistical significant difference between the treatment groups in favor of the group allocated to exercise therapy on the primary outcomes HOOS pain and HOOS function and also in the secondary outcome ICOAP. At 12 months follow-up there were no statistical differences between the treatment groups.