ABSTRACT
BACKGROUND: Intra-articular injections of hyaluronic acid-also called viscosupplementation (VS)-is frequently used for the symptomatic treatment of knee osteoarthritis, a painful and debilitating long-term disease, affecting an important fraction of elderly populations. Severity of knee osteoarthritis is generally described by Kellgren-Lawrence (KL) radiological classification. VS has been widely studied in many clinical trials; however, the results are rarely analyzed in detail according to KL grade. METHOD: A large, clinical, open-label study was performed in 2004-2007 on 1177 patients with knee osteoarthritis, each treated with VS consisting of 3 injections of Arthrum H 2% (LCA Pharmaceutical, Chartres, France). The characteristics of the patients at baseline included demographic profile, body mass index, KL grade, and clinical scores for pain and function using the Western Ontario and McMaster Universities index. Follow-up visits were at 3, 6, and 9 months after VS procedure. This large database was entirely reprocessed in 2019 to provide a separate analysis per KL grade, complemented by the assessment of the Outcome Measures in Rheumatoid Arthritis Clinical Trials-Osteoarthritis Research Society International rates (%) of responders to the treatment. The analysis was carried out for both intention-to-treat and per-protocol completer populations. RESULTS: A primary outcome in the intention-to-treat analysis, variations of the Western Ontario and McMaster Universities index pain subscore from inclusion to the end of the study were 19.8, 19.8, 17.8, and 14.2 for KL grade I to KL grade IV patients, respectively, on a 0 to 100 scale. In the per-protocol analysis, under the same conditions, the variations were 20.6, 19.9, 17.1, and 11.7. All results were significant (P < 0.001) and clinically relevant for each KL grade. Significant improvements were also observed for the Western Ontario and McMaster Universities index function subscore and for the other secondary outcomes. The Outcome Measures in Rheumatoid Arthritis Clinical Trials-Osteoarthritis Research Society International responders rate reached 72% to 82% for KL grade I through III patients at Month 6 and Month 9. For KL grade IV patients, the maximum rate reached was 47.7% at Month 6. There was evidence that KL grade is a critical parameter, particularly if KL grade IV is present. Other parameters such as gender, body mass index, and age were not identified as prognostic factors of response to VS based on χ2 and odds ratio (95% CI) testing. CONCLUSIONS: Detailed analysis by KL grade supports that VS treatment with Arthrum H 2% applies to a large variety of patients with knee osteoarthritis.
ABSTRACT
Development of the vertebrate forebrain and craniofacial structures are intimately linked processes, the coordinated growth of these tissues being required to ensure normal head formation. In this study, we identify five small subsets of progenitors expressing the transcription factor dbx1 in the cephalic region of developing mouse embryos at E8.5. Using genetic tracing we show that dbx1-expressing cells and their progeny have a modest contribution to the forebrain and face tissues. However, their genetic ablation triggers extensive and non cell-autonomous apoptosis as well as a decrease in proliferation in surrounding tissues, resulting in the progressive loss of most of the forebrain and frontonasal structures. Targeted ablation of the different subsets reveals that the very first dbx1-expressing progenitors are critically required for the survival of anterior neural tissues, the production and/or migration of cephalic neural crest cells and, ultimately, forebrain formation. In addition, we find that the other subsets, generated at slightly later stages, each play a specific function during head development and that their coordinated activity is required for accurate craniofacial morphogenesis. Our results demonstrate that dbx1-expressing cells have a unique function during head development, notably by controlling cell survival in a non cell-autonomous manner.