Study Design.Basic experiments in a mouse model of ossification of the posterior longitudinal ligament (OPLL).Objective.To assess the osteogenic potential of mesenchymal stem cells (MSCs) obtained from muscle and adipose tissue in Tiptoe-walking (ttw) mice, in which cervical OPLL compresses the spinal cord and causes motor and sensory dysfunction.Summary of Background Data.In humans, MSCs have been implicated in the pathogenesis of cervical OPLL. Cervical OPLL in ttw mice causes chronic compression of the spinal cord. Few studies have compared the MSC osteogenic potential with behavioral changes in an OPLL animal model.Methods.We compared the osteogenic potential and behavioral characteristics of MSCs from ttw mice (4 to 20 weeks old) with those from control wild-type mice (without hyperostosis). Ligament ossification was monitored by micro-computed tomography and pathology; tissues were double stained with fluorescent antibodies against markers for MSCs (CD45 and CD105), at 8 weeks. The Basso Mouse Scale was used to assess motor function, and heat and mechanical tests to assess sensory function. The osteogenic potential of adipose and muscle MSCs was assessed by Alizarin Red S absorbance, staining for osteogenic mineralization, and real-time quantitative polymerase chain reaction for osteogenesis-related genes.Results.Spinal-ligament ossification began in ttw mice at 8 weeks of age, and the ossified area increased with age. Immunofluorescence staining identified MSCs in the ossification area. The ttw mice became hyposensitive at 8 weeks of age, and Basso Mouse Scale scores showed motor-function deficits starting at 12 weeks of age. Alizarin Red S staining for mineralization showed a higher osteogenic potential in the adipose- and muscle-derived MSCs from ttw mice than from wild-type mice at 4, 8, and 20 weeks of age. Real-time quantitative polymerase chain reaction showed that ttw MSCs strongly expressed osteogenesis-related genes.Conclusion.MSCs derived from muscle and adipose tissue in ttw mice had a high osteogenic potential.Level of Evidence: N/A
Purpose: The purposes of this study were to examine population-based reference data for sex-and age-related differences between the 2011 revised Knee Society Score (KSS2011) and the Knee injury and Osteoarthritis Outcome Score (KOOS), to assess the correlation between those scores and radiographic knee osteoarthritis (OA), and to validate the use of the scores in a general Japanese population. Methods: This cross-sectional study included 963 volunteers (368 males, 595 females; mean age: 54.7 years). Participants were classified into five subgroups by age: under 40, 40s, 50s, 60s, and over 70 years old. The KSS2011 and KOOS were determined using self-administered questionnaires. Weight-bearing radiographs of the bilateral knee were taken and graded according to the Kellgren-Lawrence (KL) scale. The mean KSS2011 and KOOS were compared among age groups. Correlations between the severity of knee OA and each score were assessed using multiple regression analysis. Results: The overall KSS2011 tended to gradually decrease with age. Most subscales of the KSS2011 did not show sex-related differences. Similarly, the overall KOOS and all its subscales steadily decreased by approximately 20 points per decade with age. Most subscales of the KOOS were significantly decreased in females over 50. The KL grade was significantly related to both the overall KOOS (β = −0.42, p b 0.001) and KSS2011 (β = −0.13, p = 0.001), though the correlation to the KOOS was stronger. Conclusion: The overall KSS2011 and KOOS appear to decrease with age. In this population, the KOOS reflects the severity of knee OA better than the KSS2011.
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