Osteoarthritis is a condition of joint failure characterized by many pathologic changes of joint-surrounding tissues. Many evidences suggest the role of both innate and adaptive immunity that interplay, resulting either in initiation or in progression of osteoarthritis. Adaptive immune cells, in particular T cells, have been demonstrated to play a role in the development of OA in animal models. However, the underlying mechanism is yet unclear. Our aim was to correlate the frequency and phenotype of tissue-infiltrating T cells in the synovial tissue and infrapatellar fat pad with radiographic grading. Our results show that CD8+ T cells are increased in osteoarthritic patients with higher radiographic grading. When peripheral blood CD8+ T cells were examined, we show that CD8+ T cells possess a significantly higher level of activation than its CD4+ T cell counterpart (P < 0.0001). Our results suggest a role for CD8+ T cells and recruitment of these activated circulating peripheral blood CD8+ T cells to the knee triggering local inflammation within the knee joint.

Objective.Osteoarthritis (OA) is a condition that features inflammation and immune responses of innate and adaptive immunity. The role of T cells in knee OA pathogenesis is still unclear. Our aim was to characterize T cell functions and their clonality in patients with knee OA in peripheral blood (PB) and infrapatellar fat pads (IPFP).Methods.We isolated T cells from PB and IPFP of patients with knee OA and PB of healthy individuals and determined soluble mediators produced from these cells. In addition, we performed a clonal analysis of activated CD8+ T cells and compared the T cell receptor β-variable gene chain (TRBV) usages between T cells in PB and IPFP of patients with knee OA.Results.Our results suggest that in patients with knee OA, circulating T cells possess a more “cytotoxic” profile or rather impaired cytokine production, but the knee microenvironment allows for these T cells to produce proinflammatory cytokines [interleukin (IL)-1β, IL-6, tumor necrosis factor], IL-17, and interferon-γ within IPFP. Activated CD8+ IPFP T cells carry different repertoire distribution from those present in PB of patients with knee OA. Shared TRBV usage of activated CD8+ IPFP T cells among the 3 patients with knee OA was also observed.Conclusion.Our study describes the nature of T cells in knee OA that may be due to “unhealthy” aging or other factors that drive healthy aging T cells into a state of imbalance, thus contributing to the pathogenesis of knee OA.

Background Silk fibroin (SF) can be processed into a hydrogel. SF/collagen hydrogel may be a suitable biomaterial for bone tissue engineering. Objectives To investigate in vitro biocompatibility and osteogenic potential of encapsulated rat bone marrow-derived mesenchymal stem cells (rat MSCs) in an injectable Thai SF/collagen hydrogel induced by oleic acid–poloxamer 188 surfactant mixture in an in vitro pilot study. Methods Rat MSCs were encapsulated in 3 groups of hydrogel scaffolds (SF, SF with 0.05% collagen [SF/0.05C], and SF with 0.1% collagen [SF/0.1C]) and cultured in a growth medium and an osteogenic induction medium. DNA, alkaline phosphatase (ALP) activity, and calcium were assayed at periodically for up to 5 weeks. After 6 weeks of culture the cells were analyzed by scanning electron microscopy and energy dispersive spectroscopy. Results Although SF hydrogel with collagen seems to have less efficiency to encapsulate rat MSCs, their plateau phase growth in all hydrogels was comparable. Inability to maintain cell viability as cell populations declined over 1–5 days was observed. Cell numbers then plateaued and were maintained until day 14 of culture. ALP activity and calcium content of rat MSCs in SF/collagen hydrogels were highest at day 21. An enhancing effect of collagen combined with the hydrogel was observed for proliferation and matrix formation; however, benefits of the combination on osteogenic differentiation and biomineralization are as yet unclear. Conclusion Rat MSCs in SF and SF/collagen hydrogels showed osteogenic differentiation. Accordingly, these hydrogels may serve as promising scaffolds for bone tissue engineering.

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Background A novel biodegradable scaffold including gelatin (G), chitooligosaccharide (COS), and demineralized bone matrix (DBM) could play a significant part in bone tissue engineering. The present study aimed to investigate the biological characteristics of composite scaffolds in combination of G, COS, and DBM for in vitro cell culture and in vivo animal bioassays. Methods Three-dimensional scaffolds from the mixture of G, COS, and DBM were fabricated into 3 groups, namely, G, GC, and GCD using a lyophilization technique. The scaffolds were cultured with mesenchymal stem cells (MSCs) for 4 weeks to determine biological responses such as cell attachment and cell proliferation, alkaline phosphatase (ALP) activity, calcium deposition, cell morphology, and cell surface elemental composition. For the in vivo bioassay, G, GC, and GCD, acellular scaffolds were implanted subcutaneously in 8-week-old male Wistar rats for 4 weeks and 8 weeks. The explants were assessed for new bone formation using hematoxylin and eosin (H&E) staining and von Kossa staining. Results The MSCs could attach and proliferate on all three groups of scaffolds. Interestingly, the ALP activity of MSCs reached the greatest value on day 7 after cultured on the scaffolds, whereas the calcium assay displayed the highest level of calcium in MSCs on day 28. Furthermore, weight percentages of calcium and phosphorus on the surface of MSCs after cultivation on the GCD scaffolds increased when compared to those on other scaffolds. The scanning electron microscopy images showed that MSCs attached and proliferated on the scaffold surface thoroughly over the cultivation time. Mineral crystal aggregation was evident in GC and greatly in GCD scaffolds. H&E staining illustrated that G, GC, and GCD scaffolds displayed osteoid after 4 weeks of implantation and von Kossa staining confirmed the mineralization at 8 weeks in G, GC, and GCD scaffolds. Conclusion The MSCs cultured in GCD scaffolds revealed greater osteogenic differentiation than those cultured in G and GC scaffolds. Additionally, the G, GC, and GCD scaffolds could promote in vivo ectopic bone formation in rat model. The GCD scaffolds exhibited maximum osteoinductive capability compared with others and may be potentially used for bone regeneration.

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Objectives: To correlate functional deficits after surgical treatment of displaced intraarticular calcaneal fractures (DIACFs) as measured through dynamic pedobarography with clinical and radiographic long-term results. Design: Retrospective single-center study. Setting: Level 1 trauma center. Patients: Sixty-five patients with unilateral DIACFs, reexamined at an average of 8.1 years after surgery. Intervention: Internal fixation of DIACF with lateral plate or percutaneous screws. Main Outcome Measurements: Dynamic pedobarography, AOFAS, Zwipp, SF-36 scores, Foot Function Index, Böhler angle, and articular congruity. Results: When compared with the uninjured side, pedobarography of the operated foot revealed a significantly increased contact area of the hindfoot and midfoot, with a decreased contact area under first/second metatarsal (MT) and first/second toe after DIACF. Maximum pressure and pressure time integral were significantly increased at the midfoot and lateral MT with a decrease under the hindfoot and first to second MT/toe. Midfoot pressure time integral correlated with the range of plantarflexion. Fracture classification correlated with MT 1 contact time. Hindfoot and MT contact times were negatively correlated with Böhler angle. Patients with the smallest side-to-side differences in pedobarogaphy had overall highest scores and significantly greater ankle/hindfoot range of motion at follow-up. Conclusions: Significant correlations were found between clinical and pedobarographic results. Increased contact areas and time at the midfoot indicating a lateral load shift correlated with inferior outcome and decreased subtalar motion. These results support the importance of reconstruction of the subtalar joint and overall bony morphology of the calcaneus with preservation of subtalar motion as necessary for global foot function. Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Background Anatomic variation and supernumerary contents in the superior peroneal tunnel, and the prominence of the retrotrochlear eminence and peroneal tubercle are related to peroneal tendon disorders. Objectives To investigate the prevalence, origin, and insertion of accessory peroneal muscles, the prominence of the retrotrochlear eminence and peroneal tubercle, and their association with peroneal tendon tears. Methods We examined 109 formalin-embalmed legs of cadavers from Thai donors. Accessory peroneal muscles and peroneal tendon tears were noted. Associations with peroneal tendon tears were evaluated using a χ2 test. Results We found 48 accessory peroneal muscles comprising 13 peroneus quartus (PQ), 33 peroneus digiti quinti (PDQ), and 2 unusual muscles. All PDQ originated from the PB tendon and inserted on various parts of the 5th toe. The PQ originated mostly from the PB muscle belly and less from the tendinous part with various insertions on the retrotrochlear eminence, peroneal tubercle, cuboid, and dorsolateral surface of the 5th metatarsal base. Two unusual accessory muscles were identified, 1 coexisting with the PQ. A PB tendon tear was found in 13% of specimens. We found no association between the peroneal tendon tears and the accessory peroneal muscles, or prominence of the retrotrochlear eminence or peroneal tubercle. Conclusions The prevalence of PQ, PDQ, and unusual accessory peroneal muscles was concordant with previous findings. We noted a new type of unusual accessory peroneal muscle coexisting with the PQ. No association was found between peroneal tendon tears and the PQ, PDQ, or prominence of the retrotrochlear eminence or peroneal tubercle.