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The image shows knee articular cartilage from a chondrocyte-specific Bmal1-knockout mouse. The tissue was stained with safranin O and fast green. Deletion of the transcription factor brain and muscle Arnt-like protein 1 (BMAL1, also known as aryl hydrocarbon receptor nuclear translocator-like protein 1), a core component of the circadian clock, results in the loss of circadian rhythm and leads to degeneration of knee cartilage. The circadian clock controls the rhythmic expression of several hundred genes in cartilage and its function can be affected by inflammation and ageing, both of which are risk factors for osteoarthritis. Studies of the circadian clock will help us better understand cartilage physiology in health and disease.
Image supplied by Dr Michal Dudek from the Faculty of Life Sciences, University of Manchester, Manchester, UK.
Current guidelines for the treatment of osteoarthritis involve exercise and lifestyle modifications as well as pharmaceutical therapeutics for effective pain management. Is this message reaching patients, and are they exercising enough?
Seropositive RA can present with two different types of autoantibodies that have distinct features: anti-citrullinated protein antibodies (ACPAs) and rheumatoid factors (RFs). With a single-cell approach, researchers provide evidence that the underlying B cell subsets of these autoantibody specificities develop in parallel by different mechanisms.
A variety of comorbidities of gout exist, but most of these associations are not causally linked. Mendelian randomization analysis of genome-wide association study data now suggests that iron overload might increase serum uric acid levels and hence the risk of gout flares.
The IL-23–IL-17 signalling pathway has paradoxical effects on bone remodelling in psoriatic arthritis and ankylosing spondylitis. In this Review, Gravallese and Schett examine the evidence for and outline the reasons behind this paradox.
Hand osteoarthritis (OA) is a heterogeneous and prevalent condition involving multiple joints. In this Review, the authors provide an update on the epidemiology, presentation and burden of hand OA, as well as on advances in imaging techniques, disease management and pathogenesis.
Our ability to interrogate the genetic and epigenetic processes that underpin disease are advancing rapidly. In this Review, Radstake and colleagues highlight insights gained into the pathogenesis of systemic sclerosis from the past 4 years of genetic and epigenetic research.
Environmental changes can sometimes be too rapid for genetic adaptation and result in a mismatch between our genetics and the environment. Osteoarthritis should be considered a mismatch disease owing to a rapid increase in prevalence that is associated with the modern lifestyle, diet and patterns of physical activity.