Oxidative stress in secondary osteoarthritis: from cartilage destruction to clinical presentation?

Due to an increasing life expectance, osteoarthritis (OA) is one of the most common chronic diseases. Although strong efforts have been made to regenerate degenerated joint cartilage, OA is a progressive and irreversible disease up to date. Among other factors the dysbalance between free radical burden and cellular scavenging mechanisms defined as oxidative stress is a relevant part of OA pathogenesis. Here, only little data are available about the mediation and interaction between different joint compartments. The article provides a review of the current literature regarding the influence of oxidative stress on cellular aging, senescence and apoptosis in different joint compartments (cartilage, synovial tissue and subchondral bone). Free radical exposure is known to promote cellular senescence and apoptosis. Radical oxygen species (ROS) involvement in inflammation, fibrosis control and pain nociception has been proven. The data from literature indicates a link between free radical burden and OA pathogenesis mediating local tissue reactions between the joint compartments. Hence, oxidative stress is likely not only to promote cartilage destruction but also to be involved in inflammative transformation, promoting the transition from clinically silent cartilage destruction to apparent OA. ROS induced by exogenous factors such as overload, trauma, local intraarticular lesion and consecutive synovial inflammation cause cartilage degradation. In the affected joint, free radicals mediate disease progression. The interrelationship between oxidative stress and OA etiology might provide a novel approach to the comprehension and therefore modification of disease progression and symptom control

Development of a Core Set of Quality Criteria for Virtual Reality Applications Designed for Older Adults: Multistep Qualitative Study

BackgroundVirtual reality (VR) applications are gaining growing significance, particularly among older adults. These applications can provide valuable support to older adults by offering immersive VR content that positively influences various aspects of their daily lives, including activities of daily living. Furthermore, VR applications can contribute to the enhancement of cognitive and motor skills, ultimately leading to an improved quality of life for older individuals. Nevertheless, to ensure a positive impact, it is crucial to develop VR experiences that are tailored to the needs and preferences of the users. ObjectiveThis study aims to develop a core set of quality criteria and guidelines for the development of user-centered VR applications specifically designed for older adults (target group). MethodsThe multistep qualitative study design comprised several key stages, beginning with a systematic literature search. This was followed by a framework analysis aimed at identifying a core set of criteria. Subsequently, these criteria underwent validation through expert workshops. The outcomes achieved through this iterative process were organized and categorized into criteria, accompanied by explanations detailing the underlying categories or codes. ResultsThe quality criteria core set for older adults–friendly VR applications has been developed through an iterative process. It is divided into 2 distinct parts, each containing criteria categorized into specific areas. The first part includes the following categories: (1) quality assurance of medical/health content, (2) data protection provisions, (3) quality requirements, (4) consumer protection, and (5) interoperability. The second part includes the following categories: (1) graphic/quality, (2) 3D character/avatar, (3) providing in-game instructions and prompts, (4) interaction, (5) navigation, and (6) promotion of user motivation and loyalty to use. The results imply a differentiated scope as well as a differentiated granularity of the criteria. ConclusionsConsidering the ongoing advancement of VR technology and the diverse needs within the older adult demographic, it is essential to assess the quality criteria core set results on an individual basis

#fitspiration: a comparison of the sport-related social media usage and its impact on body image in young adults

Abstract Background Following and posting sport-related content on social media is wide-spread among young people. To date, little is known about the interdependence between sport-related social media use and the thereby perceived personal body image. Methods We conducted an online survey (N = 285) to examine how social media influences the sport-related body image. Results In general, social media are frequently used for sport (n = 136, 47.7%). Resistance training correlated significantly with several motives of sport-related use of social media, and thus, represents the strong online presence of athletic sports. Less correlations could be found in team or other sports. Regarding the perception of body image, it was found that the group of rejecting (negative) body image significantly correlated with the emulation of social media mediated sport-related beauty and body ideals (r = 0.63, p = 0.001), as well as with increased body dissatisfaction when viewing sport-related posts on social media (r = 0.590, p = 0.001). Perceived social pressure and comparison were found to be mediators of the prevailing influence of social media usage. Conclusions These results reveal the importance of taking a closer look at socially shaped beauty and body ideals, especially in sport-related contents, striving for more educational campaigns such as Body Positivity and, above all, filtering information. Finally, future research is needed to gain deeper insight into young persons’ usage behavior of social media and its impact on the individual’s body image. Trial Registration The study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Ethics Committee of University of the Federal Armed Forces Munich, Germany (01/24/2022)

Increased Ca2+ sensitivity of myofibrillar tension in ischaemic vs dilated cardiomyopathy

P>1. There is evidence that different aetiologies of heart failure, especially ischaemic vs dilated cardiomyopathy (ICM and DCM, respectively), may influence the prognosis of patients with this disease. Patients with ICM have a worse prognosis than those with DCM; the mechanisms underlying this difference have not yet been clarified. The aim of the present study was to investigate whether there are changes in myofibrillar function depending on the aetiology of human heart failure. 2. Ca2+-dependent tension (DT) and actomyosin ATPase acitivity (MYO) in Triton X-skinned fibre preparations of the left ventricular myocardium from patients with heart failure due to ICM (n = 5) and DCM (n = 5) were measured. Tension-dependent ATP consumption was calculated by the ratio of DT and MYO ('tension cost'). Non-failing myocardium (NF) from donor hearts, which could not be transplanted because of technical reasons, was evaluated as a control. 3. Although DT was reduced, the myofibrillar Ca2+ sensitivity of DT and MYO, as well as tension cost, were increased in preparations from ICM and DCM myocardium compared with NF. The Ca2+ sensitivity of DT and MYO was significantly increased in ICM compared with DCM preparations, resulting in more economic cross-bridge cycling in ICM than in DCM. 4. In conclusion, ICM is associated with an increased Ca2+ sensitivity of myofibrillar tension and ATPase activity accompanied by decreased tension cost compared with DCM. Thus, the worse prognosis associated with ICM does not seem to be due to differences in myofibrillar function

Total beta-adrenoceptor knockout slows conduction and reduces inducible arrhythmias in the mouse heart.

INTRODUCTION: Beta-adrenoceptors (β-AR) play an important role in the neurohumoral regulation of cardiac function. Three β-AR subtypes (β(1), β(2), β(3)) have been described so far. Total deficiency of these adrenoceptors (TKO) results in cardiac hypotrophy and negative inotropy. TKO represents a unique mouse model mimicking total unselective medical β-blocker therapy in men. Electrophysiological characteristics of TKO have not yet been investigated in an animal model. METHODS: In vivo electrophysiological studies using right heart catheterisation were performed in 10 TKO mice and 10 129SV wild type control mice (WT) at the age of 15 weeks. Standard surface ECG, intracardiac and electrophysiological parameters, and arrhythmia inducibility were analyzed. RESULTS: The surface ECG of TKO mice revealed a reduced heart rate (359.2±20.9 bpm vs. 461.1±33.3 bpm; p<0.001), prolonged P wave (17.5±3.0 ms vs. 15.1±1.2 ms; p = 0.019) and PQ time (40.8±2.4 ms vs. 37.3±3.0 ms; p = 0.013) compared to WT. Intracardiac ECG showed a significantly prolonged infra-Hisian conductance (HV-interval: 12.9±1.4 ms vs. 6.8±1.0 ms; p<0.001). Functional testing showed prolonged atrial and ventricular refractory periods in TKO (40.5±15.5 ms vs. 21.3±5.8 ms; p = 0.004; and 41.0±9.7 ms vs. 28.3±6.6 ms; p = 0.004, respectively). In TKO both the probability of induction of atrial fibrillation (12% vs. 24%; p<0.001) and of ventricular tachycardias (0% vs. 26%; p<0.001) were significantly reduced. CONCLUSION: TKO results in significant prolongations of cardiac conduction times and refractory periods. This was accompanied by a highly significant reduction of atrial and ventricular arrhythmias. Our finding confirms the importance of β-AR in arrhythmogenesis and the potential role of unspecific beta-receptor-blockade as therapeutic target