Pathobiology of obesity and osteoarthritis: integrating biomechanics and inflammation

Effects of exergames on rehabilitation outcomes in patients with osteoarthritis. A systematic review

PURPOSE

To analyze the effects of exergames on rehabilitation outcomes in osteoarthritis (OA) patients.

MATERIALS AND METHODS

A systematic review was reported according to the PRISMA statement. Randomized controlled trials (RCTs) were searched in Pubmed, Scopus, WoS, CINAHL, and PEDro (inception to November 2023). Studies that applied non-immersive exergames and assessed physical, functional, cognitive, pain, and psychosocial outcomes were included. Comparisons were other exercise modalities and non-intervention. Methodological quality was assessed with PEDro scale, and risk of bias (RoB) was assessed with Cochrane RoB-2 tool.

RESULTS

Eight studies were included (total of participants = 401). The mean PEDro score was 6.1, and seven studies had high RoB. Seven studies involved knee OA and one cervical OA. The most frequent duration for interventions was four weeks. Exergames were more effective than controls in at least one outcome in all studies. The outcomes for which exergames were most effective were functional disability, postural balance, muscle strength, proprioception, gait, range of motion, pain, quality of life, depression, and kinesiophobia.

CONCLUSION

Non-immersive exergames constitute an effective strategy for optimizing several relevant outcomes in rehabilitation. However, more RCTs with high methodological quality are required to deepen the knowledge about the multidimensional effects of exergames in OA patients.

Efficacy of a new treatment algorithm for capsulitis of the fingers in rock climbers

Background

Although finger joint capsulitis has been described among the most frequent injuries in climbers, no clinical studies on treatment strategies and outcomes are available.

Study design

Prospective case series study.

Methods

Between 2015 and 2018 we prospectively treated 50 patients (38 male, 12 female) with a total number of 69 independent finger joint capsulitis according to a clinic specific treatment regimen and evaluated the outcome retrospectively. Therapy consisted of either conservative management, steroid injections, radiosynoviorthesis or a combination depending on the treatment regimen, prior therapy and timeline of symptoms. Outcomes were assessed using visual analogue scale (VAS), Buck-Gramcko score and a climbing specific outcome score with secondary patient recall.

Results

The proximal interphalangeal joint of the middle finger was the most commonly affected joint, and there was no correlation with osteoarthritis. All climbers returned to sport within 12 months. The majority were able to maintain their level of performance after injury and the difference in climbing level before and after injury was not statistically significant (p = 0.22). The total time spent climbing was significantly less after the injury than before the injury (p < 0.001). The Buck-Gramcko score showed excellent results. The overall functional outcome was good to very good with a mean score of 1.6 ± 0.7, as was the climbing specific score of 1.7 ± 0.9. Pain was significantly less after treatment than before (p < 0.001).

Conclusion

Good to very good functional and sport-specific outcomes were seen with the stage-specific treatment regimen presented, allowing all patients studied to resume climbing. A better understanding of the underlying pathogenesis is essential in order to better assess long-term progress.

Hck promotes IL-1β-induced extracellular matrix degradation, inflammation, and apoptosis in osteoarthritis via activation of the JAK-STAT3 signaling pathway

We investigated role of haematopoietic cell kinase (Hck) in osteoarthritis (OA) and to explore the underlying mechanisms driving its effects. An OA animal model was established and after OA induction, rats received intra-articular injections of lentivirus twice a week for four weeks. Rats were divided into four groups: control (healthy rats without OA), OA model (rats with induced OA), OA + Len-si-NC (OA rats treated with a non-targeting control lentivirus), and OA + Len-si-Hck (OA rats treated with lentivirus targeting Hck). Blood samples were collected, and serum cytokine levels were measured using ELISA. Afterward, the rats were sacrificed for histological analysis and TUNEL assay. In vitro, IL-1β-treated human chondrocytes were transfected with Hck, and the effects on cell viability, apoptosis, ECM degradation, and JAK-STAT3 signaling were assessed. Colivelin, a JAK-STAT3 agonist, was used to confirm the pathway's involvement. Results indicated increased Hck expression in the cartilage tissues of OA rats and in IL-1β-stimulated chondrocytes. Silencing Hck in vivo reduced IL-6 and TNF-α levels, apoptosis, and preserved cartilage structure. In vitro, Hck knockdown in IL-1β-treated chondrocytes resulted in enhanced cell viability, reduced apoptosis, and decreased ECM degradation. Notably, the expression of MMP3 and MMP13 was significantly lowered, while collagen II and aggrecan levels were restored. Additionally, Hck knockdown inhibited JAK-STAT3 activation, which was evident from reduced levels of phosphorylated JAK1 and STAT3. The addition of colivelin reversed these effects, confirming that Hck mediates its effects through the JAK-STAT3 pathway. Overall, our findings indicate that Hck is critical in OA progression by promoting inflammation, apoptosis, and ECM degradation through the JAK-STAT3 signaling pathway activation.

Cellular and molecular mechanisms underlying obesity in degenerative spine and joint diseases

Degenerative spine and joint diseases, including intervertebral disc degeneration (IDD), ossification of the spinal ligaments (OSL), and osteoarthritis (OA), are common musculoskeletal diseases that cause pain or disability to the patients. However, the pathogenesis of these musculoskeletal disorders is complex and has not been elucidated clearly to date. As a matter of fact, the spine and joints are not independent of other organs and tissues. Recently, accumulating evidence demonstrates the association between obesity and degenerative musculoskeletal diseases. Obesity is a common metabolic disease characterized by excessive adipose tissue or abnormal adipose distribution in the body. Excessive mechanical stress is regarded as a critical risk factor for obesity-related pathology. Additionally, obesity-related factors, mainly including lipid metabolism disorder, dysregulated pro-inflammatory adipokines and cytokines, are reported as plausible links between obesity and various human diseases. Importantly, these obesity-related factors are deeply involved in the regulation of cell phenotypes and cell fates, extracellular matrix (ECM) metabolism, and inflammation in the pathophysiological processes of degenerative spine and joint diseases. In this study, we systematically discuss the potential cellular and molecular mechanisms underlying obesity in these degenerative musculoskeletal diseases, and hope to provide novel insights for developing targeted therapeutic strategies.

A synoptic literature review of animal models for investigating the biomechanics of knee osteoarthritis

Osteoarthritis (OA) is a common chronic disease largely driven by mechanical factors, causing significant health and economic burdens worldwide. Early detection is challenging, making animal models a key tool for studying its onset and mechanically-relevant pathogenesis. This review evaluate current use of preclinical in vivo models and progressive measurement techniques for analysing biomechanical factors in the specific context of the clinical OA phenotypes. It categorizes preclinical in vivo models into naturally occurring, genetically modified, chemically-induced, surgically-induced, and non-invasive types, linking each to clinical phenotypes like chronic pain, inflammation, and mechanical overload. Specifically, we discriminate between mechanical and biological factors, give a new explanation of the mechanical overload OA phenotype and propose that it should be further subcategorized into two subtypes, post-traumatic and chronic overloading OA. This review then summarises the representative models and tools in biomechanical studies of OA. We highlight and identify how to develop a mechanical model without inflammatory sequelae and how to induce OA without significant experimental trauma and so enable the detection of changes indicative of early-stage OA in the absence of such sequelae. We propose that the most popular post-traumatic OA biomechanical models are not representative of all types of mechanical overloading OA and, in particular, identify a deficiency of current rodent models to represent the chronic overloading OA phenotype without requiring intraarticular surgery. We therefore pinpoint well standardized and reproducible chronic overloading models that are being developed to enable the study of early OA changes in non-trauma related, slowly-progressive OA. In particular, non-invasive models (repetitive small compression loading model and exercise model) and an extra-articular surgical model (osteotomy) are attractive ways to present the chronic natural course of primary OA. Use of these models and quantitative mechanical behaviour tools such as gait analysis and non-invasive imaging techniques show great promise in understanding the mechanical aspects of the onset and progression of OA in the context of chronic knee joint overloading. Further development of these models and the advanced characterisation tools will enable better replication of the human chronic overloading OA phenotype and thus facilitate mechanically-driven clinical questions to be answered.

Critical signaling molecules in the temporomandibular joint osteoarthritis under different magnitudes of mechanical stimulation

The mechanical stress environment in the temporomandibular joint (TMJ) is constantly changing due to daily mandibular movements. Therefore, TMJ tissues, such as condylar cartilage, the synovial membrane and discs, are influenced by different magnitudes of mechanical stimulation. Moderate mechanical stimulation is beneficial for maintaining homeostasis, whereas abnormal mechanical stimulation leads to degeneration and ultimately contributes to the development of temporomandibular joint osteoarthritis (TMJOA), which involves changes in critical signaling molecules. Under abnormal mechanical stimulation, compensatory molecules may prevent degenerative changes while decompensatory molecules aggravate. In this review, we summarize the critical signaling molecules that are stimulated by moderate or abnormal mechanical loading in TMJ tissues, mainly in condylar cartilage. Furthermore, we classify abnormal mechanical stimulation-induced molecules into compensatory or decompensatory molecules. Our aim is to understand the pathophysiological mechanism of TMJ dysfunction more deeply in the ever-changing mechanical environment, and then provide new ideas for discovering effective diagnostic and therapeutic targets in TMJOA.

Weight Gain in Midlife Women

PURPOSE OF REVIEW

To summarize the evidence and clinical implications of weight and body composition changes during midlife in women and provide an overview of weight gain prevention and management in this population.

RECENT FINDINGS

Aging-related changes such as decreased energy expenditure and physical activity are important culprits for weight gain in midlife women. The hormonal changes of menopause also influence body adiposity distribution and increase central adiposity. These body changes can have health consequences including the development of cardiometabolic diseases, osteoarthritis, cancer, worsening in cognition, mental health, and menopause symptoms. Midlife women experience changes related to aging, menopause, and lifestyle which favor weight gain. Clinical practice should focus on early counseling and anticipatory guidance on the importance of dietary changes and physical activity to attenuate this phenomenon. Future research should focus on the longitudinal relationship between weight trends in midlife and health consequences and mortality.

Injection of Autologous Adipose Stromal Vascular Fraction in Combination with Autologous Conditioned Plasma for the Treatment of Advanced Knee Osteoarthritis Significantly Improves Clinical Symptoms

(1) Background: Osteoarthritis (OA) is the most common joint disease in the world. It is chronic, systemic, progressive and disabling. Orthobiologics have the potential to positively alter the course of this disease. Therefore, the aim of this study is to evaluate the efficacy of SVF/ACP in the treatment of advanced osteoarthritis of the knee in an unfiltered patient population. We hypothesize that this therapy can improve the symptoms associated with osteoarthritis of the knee. We also hypothesize that there are patient-related factors that influence the efficacy of therapy. (2) Methods: Two hundred and thirteen patients with moderate to severe OA of the knee and SVF/ACP injection were recruited for this study. Patients were excluded if they did not provide informed consent or were not receiving SVF/ACP therapy. Pain, function, symptoms and quality of life were assessed using standardized scores (KOOS, WOMAC) before and after treatment. (3) Results: The VAS pain score was significantly reduced by at least 30% (p < 0.001). Knee function, as measured by the KOOS daily activity and sport scores, showed significant increases of 21% and 45%, respectively, at 6 months (p < 0.04). (4) Conclusions: Treatment of knee OA with SVF/ACP injection positively modifies the disease by significantly reducing pain and improving function.

Overweight among Medical Students of a Medical College

Introduction

Overweight and obesity are rapidly increasing worldwide, posing a significant global health challenge. Medical students are at a higher risk of developing obesity due to factors such as a sedentary lifestyle, inadequate physical activity, unhealthy eating patterns, elevated stress levels, and the extensive amount of information they need to learn. The aim of this study was to find out the prevalence of overweight among medical students of a medical college.

Methods

A descriptive cross-sectional study was conducted among medical students of a medical college from 5 October 2022 to 10 November 2022 after obtaining ethical approval from the Institutional Review Committee. Height in meters and weight in kilograms of students were measured to calculate body mass index. A convenience sampling method was used. The point estimate at a 95% Confidence Interval was calculated.

Results

Among 261 medical students, 43 (16.47%) (11.97-20.97, 95% Confidence Interval) were overweight. Among them, 32 (74.41%) males and 11 (25.58%) females were overweight respectively.

Conclusions

The prevalence of overweight among medical students is lower than in other studies done in similar settings.

Keywords

body mass index; obesity; overweight; prevalence.

Risk of metabolic abnormalities in osteoarthritis: a new perspective to understand its pathological mechanisms

Although aging has traditionally been viewed as the most important risk factor for osteoarthritis (OA), an increasing amount of epidemiological evidence has highlighted the association between metabolic abnormalities and OA, particularly in younger individuals. Metabolic abnormalities, such as obesity and type II diabetes, are strongly linked to OA, and they affect both weight-bearing and non-weight-bearing joints, thus suggesting that the pathogenesis of OA is more complicated than the mechanical stress induced by overweight. This review aims to explore the recent advances in research on the relationship between metabolic abnormalities and OA risk, including the impact of abnormal glucose and lipid metabolism, the potential pathogenesis and targeted therapeutic strategies.

Two Amnion-Derived Mesenchymal Stem-Cells Injections to Osteoarthritic Elbows in Dogs-Pilot Study

The aim of the study was to investigate the potential of cell-based regenerative therapy for elbow joints affected by osteoarthritis. Interest was focused on two intra-articular applications of amnion-derived mesenchymal stem cells (A-MSCs) to a group of different breeds of dogs with elbow osteoarthritis (13 joints). Two injections were performed 14 days apart. We evaluated synovial fluid biomarkers, such as IFN-γ, IL-6, IL-15, IL-10, MCP-1, TNF-α, and GM-CSF, by multiplex fluorescent micro-bead immunoassay in the treated group of elbows (n = 13) (day 0, day 14, and day 28) and in the control group of elbows (n = 9). Kinematic gait analysis determined the joint range of motion (ROM) before and after each A-MSCs application. Kinematic gait analysis was performed on day 0, day 14, and day 28. Kinematic gait analysis pointed out improvement in the average range of motion of elbow joints from day 0 (38.45 ± 5.74°), day 14 (41.7 ± 6.04°), and day 28 (44.78 ± 4.69°) with statistical significance (p < 0.05) in nine elbows. Correlation analyses proved statistical significance (p < 0.05) in associations between ROM (day 0, day 14, and day 28) and IFN-γ, IL-6, IL-15, MCP-1, TNF-α, and GM-CSF concentrations (day 0, day 14, and day 28). IFN-γ, IL-6, IL-15, MCP-1, GM-CSF, and TNF- α showed negative correlation with ROM at day 0, day 14, and day 28, while IL-10 demonstrated positive correlation with ROM. As a consequence of A-MSC application to the elbow joint, we detected a statistically significant (p < 0.05) decrease in concentration levels between day 0 and day 28 for IFN-γ, IL-6, and TNF-α and statistically significant increase for IL-10. Statistical significance (p < 0.05) was detected in TNF-α, IFN-γ, and GM-CSF concentrations between day 14 and the control group as well as at day 28 and the control group. IL-6 concentrations showed statistical significance (p < 0.05) between day 14 and the control group.

The effect of interactions between BMI and sustained depressive symptoms on knee osteoarthritis over 4 years: data from the osteoarthritis initiative

BACKGROUND

To assess the compound effects of BMI and sustained depressive symptoms on changes in knee structure, cartilage composition, and knee pain over 4 years using statistical interaction analyses.

METHODS

One thousand eight hundred forty-four individuals from the Osteoarthritis Initiative Database were analyzed at baseline and 4-year follow-up. Individuals were categorized according to their BMI and presence of depressive symptoms (based on the Center for Epidemiological Studies Depression Scale (threshold≥16)) at baseline and 4-year follow-up. 3 T MRI was used to quantify knee cartilage T₂ over 4 years, while radiographs were used to assess joint space narrowing (JSN). Mixed effects models examined the effect of BMI-depressive symptoms interactions on outcomes of cartilage T₂, JSN, and knee pain over 4-years.

RESULTS

The BMI-depressive symptoms interaction was significantly associated with knee pain (p < 0.001) changes over 4 years, but not with changes in cartilage T₂ (p = 0.27). In women, the BMI-depressive symptoms interaction was significantly associated with JSN (p = 0.01). In a group-based analysis, participants with obesity and depression had significantly greater 4-year changes in knee pain (coeff._{(obesity + depression vs. no_obesity + no_depression)} = 4.09, 95%CI = 3.60-4.58, p < 0.001), JSN (coeff. = 0.60, 95%CI = 0.44-0.77, p < 0.001), and cartilage T₂ (coeff. = 1.09, 95%CI = 0.68-1.49, p < 0.001) than participants without depression and normal BMI.

CONCLUSIONS

The compound effects of obesity and depression have greater impact on knee pain and JSN progression compared to what would be expected based on their individual effects.

Self-Reported Health of Severely Obese US Adults With Osteoarthritis

BACKGROUND

Severe obesity is associated with complications following arthroplasty, leading surgeons to increasingly counsel patients regarding weight loss. For patients seeking arthroplasty, learning that severe obesity may be a relative contraindication to surgery can create a challenging clinical interaction. We sought to describe the self-reported health of United States (US) adults who had severe obesity and osteoarthritis (OA) to better understand patient perspectives.

METHODS

The National Health and Nutrition Examination Survey, a nationally representative sample of the US population, was used to identify adult participants who had a body mass index (BMI) over 35 and an OA diagnosis. In total, 889 participants representing a US population of 9,604,722 were included. Self-reported health was dichotomized as poor to fair versus good to excellent. Analyses were weighted to produce national estimates. Associations between obesity severity and patient characteristics with self-reported health were assessed.

RESULTS

Of US adults with a BMI over 35 and OA diagnosis, 64% rated their health as good or better. For adults who had a BMI over 45, 55% still reported their health as good or better. The strongest predictors of self-reported health were measures of physical functioning. Only 37% of participants who had much difficulty walking a quarter mile rated their health as good or better compared to 86% without difficulty (P < .001).

CONCLUSION

Approximately two-thirds of patients who have severe obesity and OA do not perceive their health as compromised and consider decreased physical function as the primary driver of decreased health. This suggests that counseling about the association between obesity and overall health may improve shared decision making and that patient satisfaction metrics may be difficult to interpret in these clinical situations.

Impact of Leptin on the Expression Profile of Macrophages during Mechanical Strain In Vitro

Childhood obesity is a growing problem in industrial societies and associated with increased leptin levels in serum and salvia. Orthodontic treatment provokes pressure and tension zones within the periodontal ligament, where, in addition to fibroblasts, macrophages are exposed to these mechanical loadings. Given the increasing number of orthodontic patients with these conditions, insights into the effects of elevated leptin levels on the expression profile of macrophages during mechanical strain are of clinical interest. Therefore, the aim of this in vitro study was to assess the influence of leptin on the expression profile of macrophages during simulated orthodontic treatment. RAW264.7 macrophages were incubated with leptin and lipopolysaccharides (LPS) from Porphyromonas gingivalis (P. gingivalis) or with leptin and different types of mechanical strain (tensile, compressive strain). Expression of inflammatory mediators including tumor necrosis factor (TNF), Interleukin-1-B (IL1B), IL6, and prostaglandin endoperoxide synthase (PTGS2) was assessed by RT-qPCR, ELISAs, and immunoblot. Without additional mechanical loading, leptin increased Tnf, Il1b, Il6, and Ptgs2 mRNA in RAW264.7 macrophages by itself and after stimulation with LPS. However, in combination with tensile or compressive strain, leptin reduced the expression and secretion of these inflammatory factors. By itself and in combination with LPS from P. gingivalis, leptin has a pro-inflammatory effect. Both tensile and compressive strain lead to increased expression of inflammatory genes. In contrast to its effect under control conditions or after LPS treatment, leptin showed an anti-inflammatory phenotype after mechanical stress.

Changes in foot progression angle during gait reduce the knee adduction moment and do not increase hip moments in individuals with knee osteoarthritis

People with knee osteoarthritis who adopt a modified foot progression angle (FPA) during gait often benefit from a reduction in the knee adduction moment. It is unknown, however, whether changes in the FPA increase hip moments, a surrogate measure of hip loading, which will increase the mechanical demand on the joint. This study examined how altering the FPA affects hip moments. Individuals with knee osteoarthritis walked on an instrumented treadmill with their baseline gait, 10° toe-in gait, and 10° toe-out gait. A musculoskeletal modeling package was used to compute joint moments from the experimental data. Fifty participants were selected from a larger study who reduced their peak knee adduction moment with a modified FPA. In this group, participants reduced the first peak of the knee adduction moment by 7.6% with 10° toe-in gait and reduced the second peak by 11.0% with 10° toe-out gait. Modifying the FPA reduced the early-stance hip abduction moment, at the time of peak hip contact force, by 4.3% ± 1.3% for 10° toe-in gait (p = 0.005, d = 0.49) and by 4.6% ± 1.1% for 10° toe-out gait (p < 0.001, d = 0.59) without increasing the flexion and internal rotation moments (p > 0.15). Additionally, 74% of individuals reduced their total hip moment at time of peak hip contact force with a modified FPA. In summary, when adopting a FPA modification that reduced the knee adduction moment, participants, on average, did not increase surrogate measures of hip loading.

Animal Models of Temporomandibular Joint Osteoarthritis: Classification and Selection

Temporomandibular joint osteoarthritis (TMJOA) is a common degenerative joint disease that can cause severe pain and dysfunction. It has a serious impact on the quality of lives of patients. Since mechanism underlying the pathogenesis of TMJOA is not fully understood, the development of effective tools for early diagnosis and disease-modifying therapies has been hindered. Animal models play a key role in understanding the pathological process of diseases and evaluating new therapeutic interventions. Although some similarities in disease processes between animals and humans are known, no one animal model is sufficient for studying all characteristics of TMJOA, as each model has different translatability to human clinical conditions. For the past 4 decades, TMJOA animal models have been studied by numerous researchers and can be broadly divided into induced, naturally occurring, and genetically modified models. The induced models can be divided into invasive models (intra-articular injection and surgical induction) or non-invasive models (mechanical loading, high-fat diet, and sleep deprivation). Different types of animal models simulate different pathological expressions of TMJOA and have their unique characteristics. Currently, mice, rats, and rabbits are commonly used in the study of TMJOA. This review sought to provide a general description of current experimental models of TMJOA and assist researchers in selecting the most appropriate models for different kinds of research.

Prevention of Osteoarthritis Progression by Statins, Targeting Metabolic and Inflammatory Aspects: A Review

Background and purpose:

Several traditional risk factors of atherosclerosis such as age, obesity, and altered lipid metabolism are shared with osteoarthritis (OA). Metabolic abnormalities and atheromatous vascular disease are linked with systemic inflammation and progression of OA. Hence, treatment of OA with statins is expected to improve metabolic abnormalities and prevent OA progression. Many studies which have addressed this issue found inconsistent results. This review aims to elucidate the effect of statins in OA by summarizing the existing data.

Methods:

Potential studies in English language published in Medline/PubMed, Scopus and Google Scholar since 2000 were searched by using keywords such as osteoarthritis, statins, progression, treatment, prevalence, synovitis, pain. Fourteen papers were found to be relevant and were summarised.

Results:

Data regarding symptomatic effect of statins in OA are scarce and the results varied from no effect to a small improvement or even increased risk of pain in knee OA. However, most studies on the incidence and progression of OA found a significant decreased risk of incident OA, as well as reduced risk of radiographic progression in statin users vs. non-users. Factors such as patient adherence, duration of treatment, and higher cumulative statin doses were associated with greater efficacy.

Conclusion:

Existing data indicate a preventing effect of statin therapy on OA progression. However, unless a formal meta-analysis with weight analysis is made, a conclusion cannot be drawn.

Effects of long-term exercise and a high-fat diet on synovial fluid metabolomics and joint structural phenotypes in mice: an integrated network analysis

OBJECTIVE

To explore how systemic factors that modify knee osteoarthritis risk are connected to 'whole-joint' structural changes by evaluating the effects of high-fat diet and wheel running exercise on synovial fluid (SF) metabolomics.

METHODS

Male mice were fed a defined control or high-fat (60% kcal fat) diet from 6 to 52 weeks of age, and half the animals were housed with running wheels from 26 to 52 weeks of age (n = 9-13 per group). Joint tissue structure and osteoarthritis pathology were evaluated by histology and micro-computed tomography. Systemic metabolic and inflammatory changes were evaluated by body composition, glucose tolerance testing, and serum biomarkers. SF metabolites were analyzed by high performance-liquid chromatography mass spectrometry. We built correlation-based network models to evaluate the connectivity between systemic and local metabolic biomarkers and osteoarthritis structural pathology within each experimental group.

RESULTS

High-fat diet caused moderate osteoarthritis, including cartilage pathology, synovitis and increased subchondral bone density. In contrast, voluntary exercise had a negligible effect on these joint structure components. 1,412 SF metabolite features were detected, with high-fat sedentary mice being the most distinct. Diet and activity uniquely altered SF metabolites attributed to amino acids, lipids, and steroids. Notably, high-fat diet increased network connections to systemic biomarkers such as interleukin-1β and glucose intolerance. In contrast, exercise increased local joint-level network connections, especially among subchondral bone features and SF metabolites.

CONCLUSION

Network mapping showed that obesity strengthened SF metabolite links to blood glucose and inflammation, whereas exercise strengthened SF metabolite links to subchondral bone structure.

Putative neural consequences of captivity for elephants and cetaceans

The present review assesses the potential neural impact of impoverished, captive environments on large-brained mammals, with a focus on elephants and cetaceans. These species share several characteristics, including being large, wide-ranging, long-lived, cognitively sophisticated, highly social, and large-brained mammals. Although the impact of the captive environment on physical and behavioral health has been well-documented, relatively little attention has been paid to the brain itself. Here, we explore the potential neural consequences of living in captive environments, with a focus on three levels: (1) The effects of environmental impoverishment/enrichment on the brain, emphasizing the negative neural consequences of the captive/impoverished environment; (2) the neural consequences of stress on the brain, with an emphasis on corticolimbic structures; and (3) the neural underpinnings of stereotypies, often observed in captive animals, underscoring dysregulation of the basal ganglia and associated circuitry. To this end, we provide a substantive hypothesis about the negative impact of captivity on the brains of large mammals (e.g., cetaceans and elephants) and how these neural consequences are related to documented evidence for compromised physical and psychological well-being.

Impact of Leptin on Periodontal Ligament Fibroblasts during Mechanical Strain

Orthodontic treatment to correct dental malocclusions leads to the formation of pressure zones in the periodontal ligament resulting in a sterile inflammatory reaction, which is mediated by periodontal ligament fibroblasts (PDLF). Leptin levels are elevated in obesity and chronic inflammatory responses. In view of the increasing number of orthodontic patients with these conditions, insights into effects on orthodontic treatment are of distinct clinical relevance. A possible influence of leptin on the expression profile of PDLF during simulated orthodontic mechanical strain, however, has not yet been investigated. In this study, PDLF were exposed to mechanical strain with or without different leptin concentrations. The gene and protein expression of proinflammatory and bone-remodelling factors were analysed with RT-qPCR, Western-blot and ELISA. The functional analysis of PDLF-induced osteoclastogenesis was analysed by TRAP (tartrate-resistant acid phosphatase) staining in coculture with human macrophages. Pressure-induced increase of proinflammatory factors was additionally elevated with leptin treatment. PDLF significantly increased RANKL (receptor activator of NF-kB ligand) expression after compression, while osteoprotegerin was downregulated. An additional leptin effect was demonstrated for RANKL as well as for subsequent osteoclastogenesis in coculture after TRAP staining. Our results suggest that increased leptin concentrations, as present in obese patients, may influence orthodontic tooth movement. In particular, the increased expression of proinflammatory factors and RANKL as well as increased osteoclastogenesis can be assumed to accelerate bone resorption and thus the velocity of orthodontic tooth movement in the orthodontic treatment of obese patients.

Exploring the Crosstalk between Hydrostatic Pressure and Adipokines: An In Vitro Study on Human Osteoarthritic Chondrocytes

Obesity is a risk factor for osteoarthritis (OA) development and progression due to an altered biomechanical stress on cartilage and an increased release of inflammatory adipokines from adipose tissue. Evidence suggests an interplay between loading and adipokines in chondrocytes metabolism modulation. We investigated the role of loading, as hydrostatic pressure (HP), in regulating visfatin-induced effects in human OA chondrocytes. Chondrocytes were stimulated with visfatin (24 h) and exposed to high continuous HP (24 MPa, 3 h) in the presence of visfatin inhibitor (FK866, 4 h pre-incubation). Apoptosis and oxidative stress were detected by cytometry, B-cell lymphoma (BCL)2, metalloproteinases (MMPs), type II collagen (Col2a1), antioxidant enzymes, miRNA, cyclin D1 expressions by real-time PCR, and β-catenin protein by western blot. HP exposure or visfatin stimulus significantly induced apoptosis, superoxide anion production, and MMP-3, -13, antioxidant enzymes, and miRNA gene expression, while reducing Col2a1 and BCL2 mRNA. Both stimuli significantly reduced β-catenin protein and increased cyclin D1 gene expression. HP exposure exacerbated visfatin-induced effects, which were counteracted by FK866 pre-treatment. Our data underline the complex interplay between loading and visfatin in controlling chondrocytes' metabolism, contributing to explaining the role of obesity in OA etiopathogenesis, and confirming the importance of controlling body weight for disease treatment.

Dietary saturated fatty acid palmitate promotes cartilage lesions and activates the unfolded protein response pathway in mouse knee joints

Increased intake of dietary saturated fatty acids has been linked to obesity and the development of Osteoarthritis (OA). However, the mechanism by which these fats promote cartilage degradation and the development of OA is not clearly understood. Here, we report the effects of consumption of common dietary saturated and unsaturated fatty acids, palmitate and oleate, respectively, on body weight, metabolic factors, and knee articular cartilage in a mouse model of diet-induced obesity. Mice fed on a diet rich in saturated or unsaturated fatty acid gained an equal amount of weight; however, mice fed a palmitate diet, but not a control or oleate diet, exhibited more cartilage lesions and increased expression of 1) unfolded protein response (UPR)/endoplasmic reticulum (ER) stress markers including BIP, P-IRE1α, XBP1, ATF4, and CHOP; 2) apoptosis markers CC3 and C-PARP; and 3) negative cell survival regulators Nupr1 and TRB3, in knee articular cartilage. Palmitate-induced apoptosis was confirmed by TUNEL staining. Likewise, dietary palmitate was also increased the circulatory levels of classic proinflammatory cytokines, including IL-6 and TNF-α. Taken together, our results demonstrate that increased weight gain is not sufficient for the development of obesity-linked OA and suggest that dietary palmitate promotes UPR/ER stress and cartilage lesions in mouse knee joints. This study validates our previous in vitro findings and suggests that ER stress could be the critical metabolic factor contributing to the development of diet/obesity induced OA.

Hyperechoic and Low Morphological Changes in the Prefemoral Fat Pad in Individuals with Knee Osteoarthritis Based on Ultrasonographic Findings

Background:

To clarify the changes in the echo intensity (EI) in the prefemoral fat pad (PFP) and identify the relationship between the PFP and clinical features of knee osteoarthritis (OA).

Methods:

Twenty-six women with knee OA (mean age: 76 years) and 17 healthy women (mean age: 73 years) were enrolled. The Kellgren and Lawrence grading scale was used for the radiographic evaluation of knee OA. The EI of the PFP was measured as grayscale values. The change ratio of the anteroposterior PFP length during quadriceps contraction was measured. Knee range of motion and pain (100-mm visual analog scale) were evaluated.

Results:

The EI was significantly higher in the OA group than in the healthy group (P < 0.001). The change ratio of the PFP in the OA group was significantly lower than that in the healthy group (P < 0.001). The ranges of knee flexion and extension were correlated with the EI of the PFP (both P < 0.01) and the change ratio of the PFP (both P < 0.01). There was no significant correlation observed with knee pain.

Conclusion:

Hyperechoic changes and a decreased change ratio of the PFP were observed in the patients with knee OA. High EI and decreased morphological PFP changes were associated with decreased ranges of motion.

Obesity alters the collagen organization and mechanical properties of murine cartilage

Osteoarthritis is a debilitating disease characterized by cartilage degradation and altered cartilage mechanical properties. Furthermore, it is well established that obesity is a primary risk factor for osteoarthritis. The purpose of this study was to investigate the influence of obesity on the mechanical properties of murine knee cartilage. Two-month old wild type mice were fed either a normal diet or a high fat diet for 16 weeks. Atomic force microscopy-based nanoindentation was used to quantify the effective indentation modulus of medial femoral condyle cartilage. Osteoarthritis progression was graded using the OARSI system. Additionally, collagen organization was evaluated with picrosirius red staining imaged using polarized light microscopy. Significant differences between diet groups were assessed using t tests with p < 0.05. Following 16 weeks of a high fat diet, no significant differences in OARSI scoring were detected. However, we detected a significant difference in the effective indentation modulus between diet groups. The reduction in cartilage stiffness is likely the result of disrupted collagen organization in the superficial zone, as indicated by altered birefringence on polarized light microscopy. Collectively, these results suggest obesity is associated with changes in knee cartilage mechanical properties, which may be an early indicator of disease progression.

Protein intake and osteosarcopenic adiposity in Korean adults aged 50 years and older

Intake of plant-based protein and recommended protein intake are associated with a lower risk of osteosarcopenic adiposity (co-occurrence of osteopenia/osteoporosis, sarcopenia, and adiposity) in elderly Korean men.

INTRODUCTION

Osteosarcopenic adiposity (OSA) syndrome is defined as the concurrent presence of osteopenia/osteoporosis, sarcopenia, and adiposity and leads to negative functional and metabolic outcomes in late adulthood. This study aimed to investigate the association between OSA and protein intake in adults aged 50 or older.

METHODS

A population-based, cross-sectional survey was conducted using the Korea National Health and Nutrition Examination Survey 2008-2009 data and included 645 men and 706 women aged 50 or older. Subjects were classified into normal and OSA groups. Protein intake was analyzed using the 24-h recall method.

RESULTS

There was no significant difference in the intake of total protein and animal-based protein between normal and OSA groups. However, in males, the intake of plant-based protein (p = 0.0031) was significantly lower in the OSA group than that in the normal group. Further, the protein intake in the OSA group was 0.96 g/kg/day, which was significantly lower than that in the normal group (1.06 g/kg/day; p = 0.0203). After adjusting for confounding factors, men over 65 years old who consumed less than the recommended nutrient intake (RNI) of 0.91 g/kg/day had 5.82 times higher risk of OSA compared with subjects consuming protein equal to or greater than the RNI amount (95% CI 1.81-18.66).

CONCLUSION

In conclusion, a protein intake of RNI or more is associated with a lower risk of OSA in Korean elderly men.

Visfatin and Rheumatoid Arthritis: Pathogenetic Implications and Clinical Utility

Objective:

Analysis and generalization of data related to visfatin involvement in the pathogenesis of inflammation at various stages of rheumatoid arthritis.

Data Synthesis:

Visfatin is an adipocytokine which has also been identified in non-adipose tissues. It influences directly on the maturation of B cells, which are involved in autoantibody production and T cell activation. Visfatin can promote inflammation via regulation of pro-inflammatory cytokines including TNF, IL-1β and IL-6. The concentration of circulating visfatin in rheumatoid arthritis patients is higher compared to healthy individuals. Several studies suggest that visfatin level is associated with rheumatoid arthritis activity, and its elevation may precede clinical signs of the relapse. In murine collagen-induced arthritis, visfatin levels were also found to be elevated both in inflamed synovial cells and in joint vasculature. Visfatin blockers have been shown to confer fast and long-term attenuation of pathological processes; however, most of their effects are transient. Other factors responsible for hyperactivation of the immune system can participate in this process at a later stage. Treatment of rheumatoid arthritis with a combination of these blockers and inhibitors of other mediators of inflammation can potentially improve treatment outcomes compared to current therapeutic strategies. Recent advances in the treatment of experimental arthritis in mice as well as the application of emerging treatment strategies obtained from oncology for rheumatoid arthritis management could be a source of novel adipokine-mediated anti-rheumatic drugs.

Conclusion:

The ongoing surge of interest in anticytokine therapy makes further study of visfatin highly relevant as it may serve as a base for innovational RA treatment.

Osteosarcopenic Obesity Associated with Poor Physical Performance in the Elderly Chinese Community

Objective

The aims of this study were to investigate the association between osteosarcopenic obesity (OSO) and physical performance in Chinese elderly communities.

Methods

Our study population is comprised of residents of the Township Central Hospital in the suburban of Tianjin, China. Participants (n=303; percent body fat (PBF): ≥25% for men and ≥32% for women) were assessed using the direct segmental multi-frequency bioelectrical impedance analysis (BIA) for body composition. Sarcopenia was defined as the lower 20th percentile of appendicular skeletal muscle mass/height² (ASMI). A quantitative ultrasound scan of each participants’ calcaneus with a T score≤−1.0 was used to identify the prevalence of osteopenia/osteoporosis (OP). We divided people into four groups: obesity only (O), osteopenic obesity (OO), sarcopenic obesity (SO), and osteosarcopenic obesity (OSO). We assessed the physical performance by grip strength, 4-m walk test (WS) and timed up and go test (TUGT).

Results

A total of 303 participants had completed data (89 men, 214 women; mean age of 68.8±6.0 years). The prevalence of OSO was 10.2% (men: 15.70%, women: 7.9%). After multiple adjustments, WS was significantly declined in OSO group when compared with the O group in men (mean value 95% CI was 0.84 (0.69, 0.99)) and women (mean value 95% CI was 0.93 (0.84, 1.02)). TUGT was significantly poorer in men (mean value 95% CI was 13.3 (10.6, 15.9)) and women (mean value 95% CI was 12.4 (11.2, 13.7)) with OSO when compared with the O group. Furthermore, the OSO group in women also had a significantly poorer TUGT compared with the OO group. The result of grip strength decreased significantly in women SO and OSO groups when compared with the O group (mean value 95% CI was 16.4 (14.5, 18.2) and 16.1 (13.9, 18.3)). But the results of grip strength in men showed no significant differences in any of the group.

Conclusion

In Chinese community-dwelling elderly, slower WS and lower balance function were associated with OSO in men and women. Lower grip strength was associated with SO and OSO in women.

Metabolomic Signature of Amino Acids, Biogenic Amines and Lipids in Blood Serum of Patients with Severe Osteoarthritis

Metabolomic analysis is an emerging new diagnostic tool, which holds great potential for improving the understanding of osteoarthritis (OA)-caused metabolomic shifts associated with systemic inflammation and oxidative stress. The main aim of the study was to map the changes of amino acid, biogenic amine and complex lipid profiles in severe OA, where the shifts should be more eminent compared with early stages. The fasting serum of 70 knee and hip OA patients and 82 controls was assessed via a targeted approach using the AbsoluteIDQ™ p180 kit. Changes in the serum levels of amino acids, sphingomyelins, phoshatidylcholines and lysophosphatidylcholines of the OA patients compared with controls suggest systemic inflammation in severe OA patients. Furthermore, the decreased spermine to spermidine ratio indicates excessive oxidative stress to be associated with OA. Serum arginine level was positively correlated with radiographic severity of OA, potentially linking inflammation through NO synthesis to OA. Further, the level of glycine was negatively associated with the severity of OA, which might refer to glycine deficiency in severe OA. The current study demonstrates significant changes in the amino acid, biogenic amine and low-molecular weight lipid profiles of severe OA and provides new insights into the complex interplay between chronic inflammation, oxidative stress and OA.

Joint Fluid Proteome after Anterior Cruciate Ligament Rupture Reflects an Acute Posttraumatic Inflammatory and Chondrodegenerative State

OBJECTIVE

The purpose of this study was to evaluate changes in the synovial fluid proteome following acute anterior cruciate ligament (ACL) injury.

DESIGN

This study represents a secondary analysis of synovial fluid samples collected from the placebo group of a previous randomized trial. Arthrocentesis was performed twice on 6 patients with an isolated acute ACL tear at a mean of 6 and 14 days postinjury. Synovial fluid was analyzed by a highly multiplexed assay of 1129 proteins (SOMAscan version 3, SomaLogic, Inc., Boulder, CO). Pathway analysis using DAVID was performed; genes included met 3 criteria: significant change between the 2 study time points using a paired t test, significant change between the 2 study time points using a Mann-Whitney nonparametric test, and significant Benjamini post hoc analysis.

RESULTS

Fifteen analytes demonstrated significant increases between time points. Five of the 15 have been previously associated with the onset and/or severity of rheumatoid arthritis, including apoliopoprotein E and isoform E3, vascular cell adhesion protein 1, interleukin-34, and cell surface glycoprotein CD200 receptor 1. Chondrodegenerative enzymes and products of cartilage degeneration all increased over time following injury: MMP-1 (P = 0.08, standardized response mean [SRM] = 1.00), MMP-3 (P = 0.05, SRM = 0.90), ADAM12 (P = 0.03, SRM = 1.31), aggrecan (P = 0.08, SRM = 1.13), and CTX-II (P = 0.07, SRM = 0.56). Notable pathways that were differentially expressed following injury were the cytokine-cytokine receptor interaction and osteoclast differentiation pathways.

CONCLUSIONS

The proteomic results and pathway analysis demonstrated a pattern of cartilage degeneration, not only consistent with previous findings but also changes consistent with an inflammatory arthritogenic process post-ACL injury.

Correlation network analysis shows divergent effects of a long-term, high-fat diet and exercise on early stage osteoarthritis phenotypes in mice

BACKGROUND

Obesity increases knee osteoarthritis (OA) risk through metabolic, inflammatory, and biomechanical factors, but how these systemic and local mediators interact to drive OA pathology is not well understood. We tested the effect of voluntary running exercise after chronic diet-induced obesity on knee OA-related cartilage and bone pathology in mice. We then used a correlation-based network analysis to identify systemic and local factors associated with early-stage knee OA phenotypes among the different diet and exercise groups.

METHODS

Male C57BL/6J mice were fed a defined control (10% kcal fat) or high fat (HF) (60% kcal fat) diet from 6 to 37 weeks of age. At 25 weeks, one-half of the mice from each diet group were housed in cages with running wheels for the remainder of the study. Histology, micro computed tomography, and magnetic resonance imaging were used to evaluate changes in joint tissue structure and OA pathology. These local variables were then compared to systemic metabolic (body mass, body fat, and glucose tolerance), inflammatory (serum adipokines and inflammatory mediators), and functional (mechanical tactile sensitivity and grip strength) outcomes using a correlation-based network analysis. Diet and exercise effects were evaluated by two-way analysis of variance.

RESULTS

An HF diet increased the infrapatellar fat pad size and posterior joint osteophytes, and wheel running primarily altered the subchondral cortical and trabecular bone. Neither HF diet nor exercise altered average knee cartilage OA scores compared to control groups. However, the coefficient of variation was ≥25% for many outcomes, and some mice in both diet groups developed moderate OA (≥33% maximum score). This supported using correlation-based network analyses to identify systemic and local factors associated with early-stage knee OA phenotypes. In wheel-running cohorts, an HF diet reduced the network size compared to the control diet group despite similar running distances, suggesting that diet-induced obesity dampens the effects of exercise on systemic and local OA-related factors. Each of the 4 diet and activity groups showed mostly unique networks of local and systemic factors correlated with early-stage knee OA.

CONCLUSION

Despite minimal group-level effects of chronic diet-induced obesity and voluntary wheel running on knee OA pathology under the current test durations, diet and exercise substantially altered the relationships among systemic and local variables associated with early-stage knee OA. These results suggest that distinct pre-OA phenotypes may exist prior to the development of disease.

Rapid Progression of Knee Pain and Osteoarthritis Biomarkers Greatest for Patients with Combined Obesity and Depression: Data from the Osteoarthritis Initiative

OBJECTIVE

To compare the progression of biochemical biomarkers of osteoarthritis (OA), knee pain, and function between nonobese patients (NON), obese patients without depression (OBESE), and obese patients with comorbid depression (O + D).

DESIGN

Utilizing the FNIH OA Biomarkers Consortium dataset, we categorized knee OA patients into NON, OBESE, and O + D groups based on body mass index and Center for Epidemiological Studies-Depression (CES-D) scores. Subjective symptoms (Knee injury and Osteoarthritis Outcome Score Quality of Life subscale (KOOS QOL), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Pain and Physical Function scores, and the Short Form-12 (SF-12) Physical Component Score [PCS]) and objective measures of cartilage degradation and bone remodeling (urinary CTXII and CTXIα) were compared among groups at baseline and 2-year follow-up.

RESULTS

Of the 600 patients, 282 (47%) were NON, 285 (47.5%) OBESE, and 33 (5.5%) O + D. The O + D group had significantly worse pain and function both at baseline and 2-year follow-up (P < 0.001 for all comparisons) as evidenced by self-reported measures on KOOS QOL, WOMAC Pain, WOMAC Physical Function, and SF-12 PCS. The O + D group also demonstrated significant increases in CTXII (P = 0.01) and CTXIα (P = 0.005), whereas the NON and OBESE groups did not.

CONCLUSIONS

The combination of inferior knee pain, physical function, and significantly greater increases in biomarkers of cartilage degradation and bony remodelling suggest a more rapid progression for obese OA patients with comorbid depression. The link between systemic disease, inflammatory burden, and progressive cartilage degradation is in line with increasing concerns about a degenerative synovial environment in early osteoarthritic knees that progress to treatment failure with biologic restoration procedures.

Clinical evaluation of fully automated thigh muscle and adipose tissue segmentation using a U-Net deep learning architecture in context of osteoarthritic knee pain

OBJECTIVE

Segmentation of thigh muscle and adipose tissue is important for the understanding of musculoskeletal diseases such as osteoarthritis. Therefore, the purpose of this work is (a) to evaluate whether a fully automated approach provides accurate segmentation of muscles and adipose tissue cross-sectional areas (CSA) compared with manual segmentation and (b) to evaluate the validity of this method based on a previous clinical study.

MATERIALS AND METHODS

The segmentation method is based on U-Net architecture trained on 250 manually segmented thighs from the Osteoarthritis Initiative (OAI). The clinical evaluation is performed on a hold-out test set bilateral thighs of 48 subjects with unilateral knee pain.

RESULTS

The segmentation time of the method is < 1 s and demonstrated high agreement with the manual method (dice similarity coeffcient: 0.96 ± 0.01). In the clinical study, the automated method shows that similar to manual segmentation (- 5.7 ± 7.9%, p < 0.001, effect size: 0.69), painful knees display significantly lower quadriceps CSAs than contralateral painless knees (- 5.6 ± 7.6%, p < 0.001, effect size: 0.73).

DISCUSSION

Automated segmentation of thigh muscle and adipose tissues has high agreement with manual segmentations and can replicate the effect size seen in a clinical study on osteoarthritic pain.

Physical inactivity and knee osteoarthritis in guinea pigs

OBJECTIVE

To investigate whether and how a sedentary lifestyle contributes to knee osteoarthritis (OA) incidence and severity.

DESIGN

An experiment was conducted using Hartley guinea pigs, an established idiopathic knee OA model. To simulate a sedentary lifestyle, growing animals (n = 18) were housed for 22 weeks in small cages that restricted their mobility, while another group of animals (n = 17) received daily treadmill exercise to simulate moderate physical activity. After the experiment, histological assessments, biochemical assays, and mechanical testing were conducted to compare tibial articular cartilage structure, strength, and degree of OA degeneration between sedentary and physically active animals. Groups were also compared based on body weight and composition, as well as gut microbial community composition assessed using fecal 16S rRNA gene sequencing.

RESULTS

Prevalence of knee OA was similar between sedentary and physically active animals, but severity of the disease (cartilage lesion depth) was substantially greater in the sedentary group (P = 0.02). In addition, during the experiment, sedentary animals developed cartilage with lower aggrecan quantity (P = 0.03) and accumulated more body weight (P = 0.005) and visceral adiposity (P = 0.007). Groups did not differ greatly, however, in terms of cartilage thickness, collagen quantity, or stiffness, nor in terms of muscle weight, subcutaneous adiposity, or gut microbial community composition.

CONCLUSIONS

Our findings indicate that a sedentary lifestyle promotes the development of knee OA, particularly by enhancing disease severity rather than risk of onset, and this potentially occurs through multiple pathways including by engendering growth of functionally deficient joint tissues and the accumulation of excess body weight and adiposity.

Association of Systemic Inflammation and Fatigue in Osteoarthritis: 2007-2010 National Health and Nutrition Examination Survey

BACKGROUND/PURPOSE

Mechanistic insight into osteoarthritis fatigue is needed as clinical management of this condition is nonspecific. Systemic inflammation is associated with fatigue in other chronic diseases. The purpose of this study was to explore the relationship between systemic inflammation and fatigue in osteoarthritis, while controlling for covariates.

METHOD

This secondary analysis with a cross-sectional, multiyear retrospective design used data from the 2007-2010 National Health and Nutrition Examination Survey. Adults with self-reported osteoarthritis who participated in an examination at a mobile center and had no comorbidities associated with fatigue or systemic inflammation were included (n = 296). Complex sample analysis, independent samples t tests, and χ² tests of independence were used to explore differences between nonfatigued and fatigued adults with osteoarthritis. Adjusted hierarchical logistic regression models were used to calculate odds of fatigue as a function of two systemic inflammatory markers, C-reactive protein (CRP), and white blood cell (WBC) count.

RESULTS

Fatigued adults with osteoarthritis had significantly higher CRP levels and WBC counts compared to nonfatigued adults with osteoarthritis. In adjusted logistic regression models, increased CRP was associated with higher odds of fatigue when controlling for age, days affected by pain, depressive symptoms, sleep quantity, and body mass index (Odds ratio [OR] = 3.38, 95% CI [1.18, 9.69]). WBC count was not associated with higher odds of fatigue when controlling for these variables (OR = 1.10, 95% CI [0.92, 1.32]).

CONCLUSION

Systemic inflammation may have a relationship with fatigue in osteoarthritis. Future work is necessary to replicate these findings in more robust studies.

Gene expression, protein profiling, and chemotactic activity of infrapatellar fat pad mesenchymal stem cells in pathologies of the knee joint

The infrapatellar fat pad (IPFP) is a periarticular adipose knee tissue. This tissue contains a large number of mesenchymal stem cells (MSCs). In the present work, we wanted to study the IPFP MSCs and their relationship and differences in two groups, anterior cruciate ligament (ACL) ruptures knees and ostheoarthrosis (OA). The IPFP of 42 patients with OA or ACL rupture were analyzed. Isolation, primary culture, and a genetic and proteomic study of MSCs from IPFP were performed. Gene expression of IL-6, tumor necrosis factor (TNF), IL-8, HSPA1A (Hsp70), CXCL10, RANTES, MMP1, MMP3, TIMP1, and BMP7 was analyzed by real-time quantitative polymerase chain reaction (RT-qPCR). We analyzed MSCs from from 12 diferents patients in two cellular pools (6 from AO disease and 6 from ALC rupture to form two cell pool), for the iTRAQ Proteomic Assay. The conditional media were used in quantitative analysis of MSC soluble factors by Luminex and for de migration assay. A higher gene expression of IL-6, TNF, CXCL10, RANTES, and MMP1 and OPG in MSCs from OA versus ACL (p < 0.05) was observed. Conversely HSPA1A, TIMP1, and RANKL showed a significant lower expression in OA-MSCs (p < 0.05). In the secretome analysis, adipsin and visfantin levels in the supernatants from OA-MSCs were lower (p < 0.05) respect to ACL-MSCs. Also, the monocytic cells migrated two-folds in the presence of conditioned media from OA-MSCs patients versus patients with ACL-MSC. The infrapatellar pad should be considered as an adipose tissue capable of producing and excreting inflammatory mediators directly in the knee joint, influencing the development and progression of knee joint pathologies.

Fatty infiltration in the thigh muscles in knee osteoarthritis: a systematic review and meta-analysis

Knee osteoarthritis is a chronic degenerative joint disease, influenced by inflammatory, mechanical and metabolic processes. Current literature shows that thigh muscles of people with knee osteoarthritis can have increased infiltration of fat, both between and within the muscles (inter- and intramuscular fat). The fatty infiltration in the thigh in this population is correlated to systemic inflammation, poor physical function, and muscle impairment and leads to metabolic impairments and muscle disfunction. The objective of this study is to systematically review the literature comparing the amount of fatty infiltration between people with knee osteoarthritis and healthy controls. A literature search on the databases MEDLINE, Embase, CINAHL SPORTDiscuss, Web of Science and Scopus from insertion to December 2018, resulted in 1035 articles, from which 7 met inclusion/exclusion criteria and were included in the review. All included studies analyzed the difference in intermuscular fat and only one study analyzed intramuscular fat. A meta-analysis (random effects model) transforming data into standardized mean difference was performed for intermuscular fat (six studies). The meta-analysis showed a standardized mean difference of 0.39 (95% confidence interval from 0.25 to 0.53), showing that people with knee osteoarthritis have more intermuscular fat than healthy controls. The single study analyzing intramuscular fat shows that people with knee osteoarthritis have more intramuscular fat fraction than healthy controls. People with knee osteoarthritis have more fatty infiltration around the thigh than people with no knee osteoarthritis. That conclusion is stronger for intermuscular fat than intramuscular fat, based on the quality and number of studies analyzed.

Phosphorus Concentration in Knee Joint Structures of Patients Following Replacement Surgery

The aim of the study was to assess phosphorus (P) concentration in structures of the knee joint—including the tibial spongy bone, articular cartilage, meniscus, anterior cruciate ligament, and infrapatellar fat pad (Hoffa’s fat pad)—of patients following knee joint replacement. The study also aimed to assess the influence of selected biological and environmental factors on P concentration in studied parts of the knee joint. Phosphorus concentration was determined using inductively coupled plasma-atomic emission spectrometry (ICP-AES). Statistically significant differences in P concentration were found between different elements of the knee joint. The highest P concentration was measured in the spongy bone (72,746.68 mg kg⁻¹ dw) and the lowest in the Hoffa’s fat pad (1203.19 mg kg⁻¹ dw). P levels were unaffected by gender, age, BMI, place of residence, smoking, or alcohol consumption. Data on P concentration in the osteoarticular elements of the knee may be useful in the interpretation and evaluation of biochemical, morphological, and mechanical changes occurring in the body.

Biomarkers of inflammation - LBP and TLR- predict progression of knee osteoarthritis in the DOXY clinical trial

OBJECTIVE

To evaluate systemic inflammatory biomarkers in symptomatic knee osteoarthritis (OA) and their association with radiographic and biochemical OA progression.

METHODS

Lipopolysaccharide (LPS) binding protein (LBP), soluble Toll-like receptor 4 (sTLR4) and interleukin 6 (IL-6) were measured in plasma of 431 knee OA patients from the doxycycline (DOXY) trial at baseline and 18 months. Plasma lipopolysaccharide and lipopolysaccharide binding protein (LBP) were also measured at 12 months. As a biochemical indicator of disease activity and OA progression, urinary (u) C-telopeptide of Type II collagen (uCTX-II) was measured in samples collected at baseline and 18 months. Change over 16 months in radiographic tibiofemoral joint space width (JSW in mm) and joint space narrowing (JSN≥0.5 mm) were used to indicate radiographic OA progression. Change over 18 months for uCTX-II was used as a secondary outcome. Both univariate and multivariable regression analyses were performed to test the association between Z-score transformed biomarkers and outcomes.

RESULTS

Baseline LBP and time-integrated concentration (TIC) of LBP over 12 and 18 months were associated with worsening joint space width (JSW) (parameter estimates: -0.1 to -0.07) and JSN (OR: 1.32 to 1.42) adjusting for treatment group, age, body mass index (BMI) and corresponding baseline radiographic measures. Baseline sTLR4 and TIC over 18 months were associated with change in uCTX-II over 18 months (adjusted parameter estimates: 0.0017 to 0.0020). Results were not modified by treatment with doxycycline.

CONCLUSION

Plasma LBP and sTLR4 were associated with knee OA progression over 16-18 months. These results lend further support for a role of systemic low-grade inflammation in the pathogenesis of knee OA progression.

Trends in procedure type, patient characteristics, and outcomes among persons with knee osteoarthritis undergoing bariatric surgery, 2005-2014

OBJECTIVE

To evaluate trends in the utilization, clinical characteristics, and inpatient outcomes among persons with knee osteoarthritis undergoing bariatric surgery.

METHOD

We used the National Inpatient Sample (NIS) to examine trends of bariatric surgeries performed on adults with clinically documented knee osteoarthritis between 2005 and 2014. We abstracted hospital setting, procedure, demographic and clinical characteristics, and inpatient surgical outcomes from each discharge. We examined temporal trends using linear regression and Cochran-Armitage test for trend.

RESULTS

The utilization of bariatric surgery among persons with knee osteoarthritis from 2005 to 2014 remained consistent, with an annual total of about 3,300 procedures performed nationally. The most common procedure type changed from laparoscopic Roux-en-Y (65%) in 2005-2006 to laparoscopic sleeve gastrectomy (58%) in 2013-2014. The median age, proportion on Medicare, and age- and sex-adjusted prevalence of diabetes increased from 46 to 51 years, 7-23%, and 28-32%, respectively. From 2005 to 2014, the median adjusted costs, in 2017 USD, for laparoscopic and open Roux-en-Y surgeries decreased from $15,100 to $13,300 (p < 0.01) and $14,100 to $10,100 (p = 0.0001), respectively, whereas the costs of laparoscopic sleeve gastrectomy and laparoscopic banding did not change significantly. In-hospital mortality remained at 0.0-0.1% from 2005 to 2014.

CONCLUSION

Although growing evidence suggests that bariatric surgery is associated with improvements in osteoarthritis pain and functional status, the utilization of bariatric surgery among morbidly obese persons with knee osteoarthritis remained consistent from 2005 to 2014. Bariatric surgery in persons with knee osteoarthritis is generally safe, as inpatient complication and mortality rates remained low despite an increase in age and number of comorbidities.

Independent effects of dietary fat and sucrose content on chondrocyte metabolism and osteoarthritis pathology in mice

Obesity is one of the most significant risk factors for knee osteoarthritis. However, therapeutic strategies to prevent or treat obesity-associated osteoarthritis are limited because of uncertainty about the etiology of disease, particularly with regard to metabolic factors. High-fat-diet-induced obese mice have become a widely used model for testing hypotheses about how obesity increases the risk of osteoarthritis, but progress has been limited by variation in disease severity, with some reports concluding that dietary treatment alone is insufficient to induce osteoarthritis in mice. We hypothesized that increased sucrose content of typical low-fat control diets contributes to osteoarthritis pathology and thus alters outcomes when evaluating the effects of a high-fat diet. We tested this hypothesis in male C57BL/6J mice by comparing the effects of purified diets that independently varied sucrose or fat content from 6 to 26 weeks of age. Outcomes included osteoarthritis pathology, serum metabolites, and cartilage gene and protein changes associated with cellular metabolism and stress-response pathways. We found that the relative content of sucrose versus cornstarch in low-fat iso-caloric purified diets caused substantial differences in serum metabolites, joint pathology, and cartilage metabolic and stress-response pathways, despite no differences in body mass or body fat. We also found that higher dietary fat increased fatty acid metabolic enzymes in cartilage. The findings indicate that the choice of control diets should be carefully considered in mouse osteoarthritis studies. Our study also indicates that altered cartilage metabolism might be a contributing factor to how diet and obesity increase the risk of osteoarthritis.

Summary: The contribution of metabolic factors to obesity-associated knee osteoarthritis is uncertain. Here, we show how dietary fat and sucrose independently alter cartilage metabolic enzymes and osteoarthritis pathophysiology in mice.

Obesity and orthodontic treatment: is there any direct relationship?

Obesity is a wide-spread condition directly or indirectly connected with an increase in the prevalence of a variety of human diseases. It affects over 50% of the western overall population. In 2017, a thorough analysis of 204 studies on obesity and cancer revealed that the condition increases the risk of the following types of cancer: stomach, colon, rectal, bile duct, pancreatic, esophagus, breast, endometrial, ovarian, kidney and multiple myeloma. The first study aiming at establishing a connection between obesity and the rate of induced orthodontic tooth movement was conducted by Saloom et al; however, it could not effectively nor significantly reveal any direct influence or effect. Despite being identified during the first week, differences could not be explained and treatment time remained unchanged. In spite of lack of studies in the literature on the connection between obesity and the rate of induced tooth movement, in clinical practice, courses or specialized training, we should not have protocols changed nor adopt any measures or expect significant differences between normal-weight and obese individuals. It should be emphasized that unsuccessful cases or cases of root resorption associated with treatment should not be assigned to obesity, since scientific data is insufficient to do so.

Inflammatory pattern of the infrapatellar fat pad in dogs with canine cruciate ligament disease

BACKGROUND

Despite the importance of inflammation during the pathogenesis of cranial cruciate ligament disease (CCLD) in dogs and despite the latest knowledge suggesting a significant role of adipose tissue in osteoarthritis, the infrapatellar fat pad (IFP) was up to now mostly disregarded in veterinary investigations. In the present study, the inflammatory activity of the IFP, the main adipose structure within the stifle joint, was thoroughly investigated to evaluate its potential impact in the pathogenesis of this common disease of our canine companions. Samples of IFP, subcutaneous adipose tissue (ScAT) of the thigh and synovial fluid in both diseased (n = 36) and healthy control (n = 23) dogs were tested for their immune cell composition but also for interleukins (IL-1β, IL-6, IL-8, IL-10), degradative enzymes (MMP-1, MMP-3, MMP-13, TIMP-2, iNOS) and adipokines (leptin and adiponectin). Characterization of the immune cell composition was ascertained by fluorescence activated cell sorting. Gene expression and protein release of the inflammatory markers was determined by real RT-qPCR and ELISA.

RESULTS

IFPs of dogs with CCLD had a significantly increased immune cell count with T cells (CD3) as the most abundant immune cells. T cells and macrophages (CD14) were significantly increased compared to healthy controls or corresponding ScAT. In addition, IFPs of dogs with CCLD demonstrated a significant increase on gene as well as protein level of multiple inflammatory indicators (IL-1β, IL-6, MMP-1, MMP-13) compared to the other tissues. TNFα was only increased on gene expression. Adipokine analysis showed higher secretion of adiponectin and lower leptin secretion in IFP from dogs with CCLD than from controls. In the synovial fluid from dogs with CCLD concentrations of IL-1β, MMP-1, MMP-13 as well as leptin were significantly increased compared to the synovial fluid from healthy control dogs.

CONCLUSIONS

The present study indicates that the IFP is a potential contributory factor in the pathogenesis of CCLD, due to its inflammatory phenotype and the proximity within the stifle joint. To determine the extent of this possible inter-relationship, further studies need to be undertaken.

Engineered Coiled-Coil Protein for Delivery of Inverse Agonist for Osteoarthritis

Osteoarthritis (OA) results from degenerative and abnormal function of joints, with localized biochemistry playing a critical role in its onset and progression. As high levels of all- trans retinoic acid (ATRA) in synovial fluid have been identified as a contributive factor to OA, the synthesis of de novo antagonists for retinoic acid receptors (RARs) has been exploited to interrupt the mechanism of ATRA action. BMS493, a pan-RAR inverse agonist, has been reported as an effective inhibitor of ATRA signaling pathway; however, it is unstable and rapidly degrades under physiological conditions. We employed an engineered cartilage oligomeric matrix protein coiled-coil (C_cc^S) protein for the encapsulation, protection, and delivery of BMS493. In this study, we determine the binding affinity of C_cc^S to BMS493 and the stimulator, ATRA, via competitive binding assay, in which ATRA exhibits approximately 5-fold superior association with C_cc^S than BMS493. Interrogation of the structure of C_cc^S indicates that ATRA causes about 10% loss in helicity, while BMS493 did not impact the structure. Furthermore, C_cc^S self-assembles into nanofibers when bound to BMS493 or ATRA as expected, displaying 11-15 nm in diameter. Treatment of human articular chondrocytes in vitro reveals that C_cc^S·BMS493 demonstrates a marked improvement in efficacy in reducing the mRNA levels of matrix metalloproteinase-13 (MMP-13), one of the main proteases responsible for the degradation of the extracellular cartilage matrix compared to BMS493 alone in the presence of ATRA, interleukin-1 beta (IL-1β), or IL-1 β together with ATRA. These results support the feasibility of utilizing coiled-coil proteins as drug delivery vehicles for compounds of relatively limited bioavailability for the potential treatment of OA.

The Value of Phenotypes in Knee Osteoarthritis Research

Background:

Over the past decade, phenotypes have been used to help categorize knee osteoarthritis patients relative to being subject to disease, disease progression, and treatment response. A review of potential phenotype selection is now appropriate. The appeal of using phenotypes is that they most rely on simple physical examination, clinically routine imaging, and demographics. The purpose of this review is to describe the panoply of phenotypes that can be potentially used in osteoarthritis research.

Methods:

A search of PubMed was used singularly to review the literature on knee osteoarthritis phenotypes.

Results:

Four phenotype assembly groups were based on physical features and noninvasive imaging. Demographics included metabolic syndrome (dyslipidemia, hypertension, obesity, and diabetes). Mechanical characteristics included joint morphology, alignment, the effect of injury, and past and present history. Associated musculoskeletal disorder characteristics included multiple joint involvement, spine disorders, neuromuscular diseases, and osteoporosis. With the knee as an organ, tissue characteristics were used to focus on synovium, meniscus, articular cartilage, patella fat pad, bone sclerosis, bone cysts, and location of pain.

Discussion:

Many of these phenotype clusters require further validation studies. There is special emphasis on knee osteoarthritis phenotypes due to its predominance in osteoarthritic disorders and the variety of tissues in that joint. More research will be required to determine the most productive phenotypes for future studies.

Conclusion:

The selection and assignment of phenotypes will take on an increasing role in osteoarthritis research in the future.

FTO variant is not associated with osteoarthritis in the Chinese Han population: replication study for a genome-wide association study identified risk loci

BACKGROUND

Osteoarthritis is the most prevalent form of arthritis worldwide and is the major cause of pain and loss of function in elderly people. A signal of the fat mass and obesity-associated (FTO) gene had been reported in a genome-wide association study of osteoarthritis. The FTO polymorphism (rs8044769) might exert its effect on osteoarthritis through obesity, because it was reported as a body mass index-associated single-nucleotide polymorphism. And replication studies showed inconsistent results for this association. Our present study is to check the association of rs8044769 with osteoarthritis and body mass index in Chinese Han population.

METHODS

A case-control association study was conducted by using 890 osteoarthritis cases and 844 controls in Chinese Han population. rs8044769 was genotyped in all subjects. Allelic and genotypic frequencies were compared between osteoarthritis cases and control subjects. Associations between rs8044769 and body mass index, and body mass index and osteoarthritis were also assessed.

RESULTS

No significant difference was detected in genotype or allele distribution between osteoarthritis cases and controls (P > 0.05). Stratification by gender and body mass index revealed negative association between rs8044769 and osteoarthritis. We did not find any solid association between rs8044769 and higher body mass index. Meanwhile, we demonstrated that higher body mass index (body mass index ≥ 25) was associated with osteoarthritis.

CONCLUSION

Our present study suggested that rs8044769 was not associated with osteoarthritis susceptibility or higher body mass index, and higher body mass index was a risk factor for osteoarthritis in the Chinese Han population. We also proposed that stratification by clinical parameters was crucial to reduce false-positive result in OA association studies.

Biomechanics, obesity, and osteoarthritis. The role of adipokines: When the levee breaks

Osteoarthritis is a high-incidence painful and debilitating disease characterized by progressive degeneration of articular joints, which indicates a breakdown in joint homeostasis favoring catabolic processes. Biomechanical loading, associated with inflammatory and metabolic imbalances of joint, strongly contributes to the initiation and progression of the disease. Obesity is a primary risk factor for disease onset, and mechanical factors increased the risk for disease progression. Moreover, inflammatory mediators, in particular, adipose tissue-derived cytokines (better known as adipokines) play a critical role linking obesity and osteoarthritis. The present article summarizes the knowledge about the role of adipokines in cartilage and bone function, highlighting their contribution to the imbalance of joint homeostasis and, consequently, pathogenesis of osteoarthritis. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:594-604, 2018.

FABP4 as a biomarker for knee osteoarthritis

Aim: To explore the role of an adipokine-termed fatty acid-binding protein 4 (FABP4) in osteoarthritis (OA). Methods: Patients with primary knee OA and non-OA controls were included. Paired tissues including plasma, synovial fluid (SF), subcutaneous fat and infrapatellar fat pad (IPFP) were harvested during surgery. FABP4 concentration was determined by ELISA. Results: Plasma FABP4 increased significantly with OA stage (n = 263). OA patients (n = 38) had significantly higher plasma and SF FABP4 than non-OA patients (n = 29). FABP4 level of IPFP was positively correlated with SF FABP4. Conclusion: OA patients had significantly high systemic and local FABP4, and IPFP may be the main source of FABP4 in synovial cavity. FABP4 may be a promising biomarker for OA.