Adipokine role in physiopathology of inflammatory and degenerative musculoskeletal diseases

Implications of obesity-mediated cellular dysfunction and adipocytokine signaling pathways in the pathogenesis of osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease characterized by cartilage degradation, bone sclerosis, and chronic low-grade inflammation. Aging and injury play key roles in OA pathogenesis by triggering the release of proinflammatory factors from adipose tissue and other sources. Obesity and aging impair the function of endoplasmic reticulum (ER) chaperones, leading to ER stress, protein misfolding, and cellular apoptosis. Obesity also induces mitochondrial dysfunction in OA through oxidative stress and disrupts mitochondrial dynamics, exacerbating chondrocyte damage. These factors contribute to inflammation, matrix imbalance, and chondrocyte apoptosis. Adipocytes, the primary source of adipokines, release inflammatory mediators that affect joint cells. Several adipocytokines have a central role in the regulation of many aspects of inflammation. Adiponectin and leptin are the two most abundant adipocytokines that are strongly associated with OA progression. This literature review suggests that adipokines activate many signaling pathways to exert downstream effects and play significant roles in obesity-induced OA. Understanding this rapidly growing family of mainly adipocyte-derived mediators and obesity-mediated cellular dysfunction may be important in the development of new therapies for obesity-associated OA management.

Do Obesity and Adipose Tissue Cytokines Influence the Response to Janus Kinase Inhibitors in Rheumatoid Arthritis?

Background: Obesity is a frequent comorbidity in rheumatoid arthritis (RA). This condition may lead these patients to have poorer disease control and a worse response to some of the available treatments. Objectives: We aim to analyze the role of body mass index (BMI) in the clinical response to Janus kinase inhibitors (JAKis) in patients with RA. We aim to perform an in-depth analysis of the pathophysiology of obesity by assessing serum adipokine levels, their potential influence in disease activity and their changes with treatment. Methods: This study involved 81 patients with RA treated with JAKis from Hospital La Paz and Hospital Reina Sofía. Patients were classified according to their BMI as normal weight and overweight/obesity. The clinical response to treatment was assessed by the Clinical Disease Activity Index (CDAI) and Disease Activity Score-28 (DAS28) 6 months after the initiation of JAKis. Serum adipokines (leptin and adiponectin) were determined using a commercial immunoassay kit in samples obtained before the initiation of JAKis and after 6 months of treatment. Results: Leptin levels showed a significant positive correlation with BMI at baseline (r = 0.59, p < 0.01) and at 6 months (r = 0.56, p < 0.01) in the whole cohort, but no correlation was found between BMI and adiponectin. No correlation between disease activity and BMI was found in the whole cohort at baseline and at 6 months measured by both the CDAI and DAS28. Fifty patients (61.7%) achieved low disease activity (LDA)/remission at 6 months, regardless their BMI, and no differences in serum adipokine levels were observed at baseline and at 6 months in patients who achieved LDA vs. no-LDA. Conclusions: In this study, we did not find an association between obesity and the extent of LDA in patients treated with JAKis; therefore, this mechanism of action could be suitable for overweight/obese patients with RA.

Molecular Assessment of Plasma Concentrations of Selected Adipokines and IL-8 in Horses with Back Pain and Comorbid Asthma-Based on Clinical Cases

Similarly, in humans and horses, thoracic and lumbosacral back pain cause more disability and work interruptions worldwide than any other disease. Given that there are few effective treatments for back pain in humans and animals, primary prevention strategies and a reduction in pain factors may be crucial. In the analysed data obtained for the horses studied, the pattern of changes in adipocytokine concentrations, including resistin, visfatin and leptin, was noted for those with back pain compared to the control animals. Concentrations of selected adipocytokines in horses from the back pain group were different in animals with a coexisting diagnosis of asthma and back dysfunction. Very few studies are available on adipokine concentrations in horses. No information was found in relation to back pain and asthma in these animals. In humans, correlations of back pain and asthma with concentrations of selected adipokines have been described.

Obesity, Metabolic Syndrome, and Osteoarthritis Require Integrative Understanding and Management

Osteoarthritis (OA) is a progressive chronic disease affecting the articular joints, leading to pain and disability. Unlike traditional views that primarily link OA to aging, recent understanding portrays it as a multifactorial degenerative disease of the entire joint. Emerging research highlights metabolic and immune dysregulation in OA pathogenesis, emphasizing the roles of obesity, dyslipidemia, and insulin resistance in altering joint homeostasis. Recent studies have increasingly focused on the complex role of white adipose tissue (WAT) in OA. WAT not only serves metabolic functions but also plays a critical role in systemic inflammation through the release of various adipokines. These adipokines, including leptin and adiponectin, have been implicated in exacerbating cartilage erosion and promoting inflammatory pathways within joint tissues. The overlapping global crises of obesity and metabolic syndrome have significantly impacted joint health. Obesity, now understood to contribute to mechanical joint overload and metabolic dysregulation, heightens the risk of developing OA, particularly in the knee. Metabolic syndrome compounds these risks by inducing chronic inflammation and altering macrophage activity within the joints. The multifaceted effects of obesity and metabolic syndrome extend beyond simple joint loading. These conditions disrupt normal joint function by modifying tissue composition, promoting inflammatory macrophage polarization, and impairing chondrocyte metabolism. These changes contribute to OA progression, highlighting the need for targeted therapeutic strategies that address both the mechanical and biochemical aspects of the disease. Recent advances in understanding the molecular pathways involved in OA suggest potential therapeutic targets. Interventions that modulate macrophage polarization, improve chondrocyte function, or normalize adipokine levels could serve as preventative or disease-modifying therapies. Exploring the role of diet, exercise, and pharmacological interventions in modulating these pathways offers promising avenues for reducing the burden of OA. Furthermore, such methods could prove cost-effective, avoiding the increase in access to healthcare.

Mendelian randomization analyses reveal no genetic causal effects of major adipokines on systemic lupus erythematosus

Epidemiological studies have shown that the levels of serum adipokine such as leptin and resistin are associated with the risk of developing systemic lupus erythematosus (SLE). Nevertheless, whether either leptin or resistin has causal impacts on the risk of SLE is still unknown. In this study, two-sample univariable MR analyses and multivariable MR analysis were performed to explore the causal relationships between adipokines and SLE. Additionally, the potential causal effects of SLE on major adipokines were evaluated using reverse MR analyses. The results of inverse-variance weighted (IVW), weighted median, weighted mode and MR‒Egger methods concordantly supported that major adipokines have no causal effects on the risk of SLE. In the multivariable MR IVW analysis with leptin and resistin as covariates, neither leptin (odds ratio (OR) = 3.093, P = 0.067) nor resistin (OR = 0.477, P = 0.311) was identified as an independent risk factor for SLE, which is in line with the univariable MR results. In conclusion, our analyses revealed no evidence to support that these three major adipokines are risk factors for SLE.

Psoriasis and Molecular Target Therapies: Evidence of Efficacy in Preventing Cardiovascular Comorbidities

Psoriasis is now considered a systemic disease, and several comorbidities have been described such as cardiovascular diseases, neurologic and psychiatric disorders, chronic inflammatory bowel disease, psoriatic arthritis, etc. Regarding cardiovascular comorbidities, major adverse cardiovascular events have been reported in psoriasis patients by multiple epidemiologic studies. Moreover, smoking, obesity, metabolic syndrome, hypertension, dyslipidemia, diabetes and reduced physical activity are associated with psoriasis, increasing cardiovascular risk. Consequently, several aspects should be considered when making the treatment decision. The aim of this review manuscript was to investigate the effectiveness and safety of biologic drugs acting on molecular mechanisms involved in the pathogenesis of psoriasis in preventing cardiovascular complications.

Concentrations of Selected Adipocytokines in the Blood Plasma in Proximal Suspensory Desmopathy of Horses, with a Focus on Their Physical Activity-A Pilot Study

Chronic tendon and ligament diseases are commonly encountered in both athletic humans and animals, especially horses. Distal limb diseases, including suspensory ligament (SL) pathology due to anatomical, histological, and biomechanical properties, can be considered a model for tendon and ligament pathologies in humans. The appropriate selection of therapy is often crucial in optimising the healing process. One decisive factor influencing the possibility of returning to pre-disease training levels appears to be the utilisation of physical activity, including controlled movement, during the rehabilitation process. In the pathogenesis of musculoskeletal diseases and rehabilitation, adipocytokines play diverse roles. However, it is unclear what significance they hold in horses and in specific disease entities as well as the consequences of their mutual interactions. Recent studies indicate that in the pathogenesis of diseases with varied aetiologies in humans, their value varies at different stages, resulting in a diverse response to treatment. The results of this study demonstrate lower resistin concentrations in the venous blood plasma of horses with proximal suspensory desmopathy (PSD), while higher levels were observed in regularly trained and paddocked animals. The horses investigated in this study showed higher concentrations of resistin and IL-8, particularly in paddocked horses as well as in the working group of horses. The results suggest that these concentrations, including resistin in blood plasma, may be clinically significant. This attempt to explore the aetiopathogenesis of the processes occurring in the area of the proximal attachment of the suspensory ligament may optimise the procedures for the treatment and rehabilitation of horses.

Periodontitis is associated with the increased levels of visfatin: a meta-analysis

OBJECTIVE

Periodontitis is a common inflammatory disease associated with systemic factors. Visfatin is a pleiotropic adipokine that exerts metabolic and immune functions. Studies have shown visfatin played roles in the development of periodontitis. The present study aims to compare the levels of visfatin in body fluids including serum, saliva, and gingival crevicular fluid (GCF) between periodontitis patients and healthy individuals, and to elucidate the alteration of visfatin levels after periodontal treatments.

MATERIALS AND METHODS

The database searched included Pubmed, Embase, Web of Science, and Cochrane Library. According to the Eligibility criteria, the records were screened and the eligible studies were included. The methodological qualities of the included case-controlled studies were assessed according to the Newcastle-Ottawa scale (NOS). The Methodological Index for Nonrandomized Studies (MINORS) was applied for assessing the qualities of the included clinical trials. The statistical analyses were processed using STATA 15.0.

RESULTS

Twenty-three studies were included in the statistical analyses. The meta-analysis showed significantly elevated visfatin levels of GCF, serum, and saliva in the periodontitis population compared with the controls (GCF: SMD = 5.201, 95% CI: 3.886-6.516, Z = 7.75, P < 0.05; Serum: SMD = 7.417, 95% CI: 3.068-11.767, Z = 3.34, P = P < 0.05; Saliva: SMD = 2.683, 95% CI: 1.202-4.163, Z = 3.34, P < 0.05). Visfatin levels of saliva serum and GCF were significantly decreased after periodontal treatment. (Saliva: SMD = -1.338, 95% CI: -2.289-0.487, Z = 39.77, P < 0.05; Serum: SMD = -2.890, 95% CI: -5.300-0.480, Z = 2.35, P < 0.05; GCF: SMD = -6.075, 95% CI: -11.032-1.117, Z = 2.40, P = 0.016; I 2 = 95.9%, P < 0.05).

CONCLUSIONS

Periodontitis elevated the visfatin levels in GCF, serum, and saliva. Additionally, GCF, serum, and saliva visfatin levels could be reduced after periodontal treatment.

Omentin-1 ameliorates the progress of osteoarthritis by promoting IL-4-dependent anti-inflammatory responses and M2 macrophage polarization

Osteoarthritis (OA) is a prevalent joint disease commonly associated with aging and obesity, which can lead to pain, stiffness, joint dysfunction, and disability. Omentin-1 (also called intelectin-1) is a newly discovered adipokine, which plays a protective role in suppressing the secretion of pro-inflammatory cytokines. Based on data from the Gene Expression Omnibus (GEO) dataset and clinical samples obtained at our institution revealed, determined that omentin-1 and IL-4 (an anti-inflammatory cytokine) levels were significantly lower in OA patients than in normal controls. Omentin-1 was shown to induce IL-4-depedent anti-inflammatory responses and M2 macrophage polarization in OA synovial fibroblasts via the PI3K, ERK, and AMPK pathways. Administering omentin-1 was shown to block cartilage degradation and bone erosion resulting from anterior cruciate ligament transection by inhibiting the production of pro-inflammatory cytokines and promoting M2 macrophage polarization in vivo. Our findings indicate omentin-1 as a promising therapeutic avenue for the treatment for OA.

Increased Expression of Adipokines in Patients With Frozen Shoulder

BACKGROUND

Adipokines represent a spectrum of bioactive molecules that could modulate fibroblastic and inflammatory processes. The role of adipokines in the pathogenesis of frozen shoulder (FS), a common musculoskeletal disorder characterized by chronic inflammation, remains obscure.

PURPOSE

To evaluate whether adipokines contribute to the pathogenic mechanisms of FS and to evaluate any potential correlation of adipokines with patients' symptoms.

STUDY DESIGN

Controlled laboratory study.

METHODS

Shoulder capsule specimens were obtained from 10 patients with FS and 10 patients with shoulder instability (control group). The specimens were dyed using hematoxylin and eosin and immunohistochemically assessed with antibodies targeting adipokines, collagen I, collagen III, and tumor necrosis factor α. Immunoreactivity was graded from "no" to "strong" in a blinded manner. Reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR) analysis was conducted. Before the surgery, patient-reported frequency of pain, severity of pain, stiffness, and shoulder range of motion were documented.

RESULTS

In comparison with the control group, patients with FS had significantly greater pain frequency, pain severity, and stiffness and more limited shoulder range of motion (P < .001). Hematoxylin and eosin- and Masson trichrome-stained samples from the FS group displayed hypercellularity and increased collagen fibers. Immunohistochemistry and RT-qPCR analyses indicated that expression of adipokines was significantly increased in FS capsules compared with the control group. The expression of collagen I, collagen III, and tumor necrosis factor α was also increased in FS capsules. No significant correlation was noted between adipokine expression and patient-reported outcomes in the control group, whereas in patients with FS, adiponectin expression was correlated with pain frequency (r = 0.78; P = .01) and stiffness (r = 0.73; P = .02). Visfatin was also correlated with pain frequency (r = 0.70; P = .02).

CONCLUSION/CLINICAL RELEVANCE

This study indicated a potential role for adipokines in the pathogenesis of FS and demonstrated a correlation between adipokine expression and patients' pain and stiffness.

The Role of BIA Analysis in Osteoporosis Risk Development: Hierarchical Clustering Approach

Osteoporosis is a common musculoskeletal disorder among the elderly and a chronic condition which, like many other chronic conditions, requires long-term clinical management. It is caused by many factors, including lifestyle and obesity. Bioelectrical impedance analysis (BIA) is a method to estimate body composition based on a weak electric current flow through the body. The measured voltage is used to calculate body bioelectrical impedance, divided into resistance and reactance, which can be used to estimate body parameters such as total body water (TBW), fat-free mass (FFM), fat mass (FM), and muscle mass (MM). This study aims to find the tendency of osteoporosis in obese subjects, presenting a method based on hierarchical clustering, which, using BIA parameters, can group patients who show homogeneous characteristics. Grouping similar patients into clusters can be helpful in the field of medicine to identify disorders, pathologies, or more generally, characteristics of significant importance. Another added value of the clustering process is the possibility to define cluster prototypes, i.e., imaginary patients who represent models of "states", which can be used together with clustering results to identify subjects with similar characteristics in a classification context. The results show that hierarchical clustering is a method that can be used to provide the detection of states and, consequently, supply a more personalized medicine approach. In addition, this method allowed us to elect BIA as a potential prognostic and diagnostic instrument in osteoporosis risk development.

Irisin as a Novel Biomarker of Subclinical Atherosclerosis, Cardiovascular Risk and Severe Disease in Axial Spondyloarthritis

Introduction

Patients with axial spondyloarthritis (axSpA) have a high disease burden mainly due to the rheumatic disease itself, and also exhibit accelerated atherosclerosis, that leads to a higher incidence of cardiovascular (CV) disease. Accordingly, the identification of biomarkers of CV risk and inflammation in axSpA patients is clinically relevant. In this sense, given the beneficial functions exerted by the adipomyokine irisin in processes related to CV disease and inflammation, our aim was to assess, for the first time, the role of irisin as a genetic and serological biomarker of subclinical atherosclerosis, CV risk and disease severity in axSpA patients.

Methods

A large cohort of 725 Spanish patients with axSpA was included. Subclinical atherosclerosis (presence of plaques and abnormal carotid intima-media thickness values) was evaluated by carotid ultrasound. Four irisin polymorphisms (rs16835198 G/T, rs3480 A/G, rs726344 G/A, and rs1570569 G/T) were genotyped by TaqMan probes. Additionally, serum irisin levels were determined by ELISA.

Results

Low irisin levels were linked to the presence of plaques (p=0.002) and atherogenic index values ≥4 (p=0.01). Serum irisin were positively correlated with C-peptide levels (p<0.001) and negatively correlated with visual analogue scale and Bath Ankylosing Spondylitis Metrology Index (p<0.05 in all the cases). Moreover, lower irisin levels were observed in patients with sacroiliitis and in those with a negative HLA-B27 status (p<0.001 and p=0.006, respectively), as well as in those treated with non-steroidal anti-inflammatory drugs and conventional disease-modifying antirheumatic drugs (p<0.001 and p=0.002, respectively). Interestingly, the TT genotype and the T allele of rs16835198 were less frequent in axSpA patients with ASDAS >2.1 (Odds Ratio (OR): 0.48 [0.28-0.83] and OR: 0.73 [0.57-0.92], respectively, p=0.01 in both cases). Additionally, the frequency of rs1570569 T allele was higher in these patients (OR: 1.46 [1.08-1.97], p=0.01). Furthermore, the GGGT haplotype was more frequent in patients with ASDAS values >2.1 (OR: 1.73 [1.13-2.66], p=0.01).

Conclusions

Our results indicate that low serum irisin levels could be indicators of the presence of subclinical atherosclerosis, high CV risk and more severe disease in axSpA patients. In addition, irisin may also constitute a genetic biomarker of disease activity in axSpA.

Cerebrospinal fluid and plasma metabolomics of acute endurance exercise

Metabolomics has emerged as a powerful new tool in precision medicine. No studies have yet been published on the metabolomic changes in cerebrospinal fluid (CSF) produced by acute endurance exercise. CSF and plasma were collected from 19 young active adults (13 males and 6 females) before and 60 min after a 90-min monitored outdoor run. The median age, BMI, and VO₂ max of subjects was 25 years (IQR 22-31), 23.2 kg/m² (IQR 21.7-24.5), and 47 ml/kg/min (IQR 38-51), respectively. Targeted, broad-spectrum metabolomics was performed by liquid chromatography, tandem mass spectrometry (LC-MS/MS). In the CSF, purines and pyrimidines accounted for 32% of the metabolic impact after acute endurance exercise. Branch chain amino acids, amino acid neurotransmitters, fatty acid oxidation, phospholipids, and Krebs cycle metabolites traceable to mitochondrial function accounted for another 52% of the changes. A narrow but important channel of metabolic communication was identified between the brain and body by correlation network analysis. By comparing these results to previous work in experimental animal models, we found that over 80% of the changes in the CSF correlated with a cascade of mitochondrial and metabolic changes produced by ATP signaling. ATP is released as a co-neurotransmitter and neuromodulator at every synapse studied to date. By regulating brain mitochondrial function, ATP release was identified as an early step in the kinetic cascade of layered benefits produced by endurance exercise.

Adipokine Signaling Pathways in Osteoarthritis

Osteoarthritis (OA) is a debilitating joint disease that affects millions of individuals. The pathogenesis of OA has not been fully elucidated. Obesity is a well-recognized risk factor for OA. Multiple studies have demonstrated adipokines play a key role in obesity-induced OA. Increasing evidence show that various adipokines may significantly affect the development or clinical course of OA by regulating the pro/anti-inflammatory and anabolic/catabolic balance, matrix remodeling, chondrocyte apoptosis and autophagy, and subchondral bone sclerosis. Several signaling pathways are involved but still have not been systematically investigated. In this article, we review the cellular and molecular mechanisms of adipokines in OA, and highlight the possible signaling pathways. The review suggested adipokines play important roles in obesity-induced OA, and exert downstream function via the activation of various signaling pathways. In addition, some pharmaceuticals targeting these pathways have been applied into ongoing clinical trials and showed encouraging results. However, these signaling pathways are complex and converge into a common network with each other. In the future work, more research is warranted to further investigate how this network works. Moreover, more high quality randomised controlled trials are needed in order to investigate the therapeutic effects of pharmaceuticals against these pathways for the treatment of OA. This review may help researchers to better understand the pathogenesis of OA, so as to provide new insight for future clinical practices and translational research.

Retrospective analysis of the relationship between bone mineral density and body composition in a health check-up Chinese population

PURPOSE

This study was designed to explore the relationship between bone mineral density (BMD) and body composition indicators in Chinese adults (≥50 years) in order to provide a scientific basis for optimal bone health management.

METHOD

Individuals ≥50 years old who received physical examinations and routine check-ups at the Health Management Research Institute of PLA General Hospital from September 2014 through March 2022 were included as research subjects in this study. Basic clinical and demographic information were recorded for all subjects, along with smoking and drinking status, height and body weight. A panel of routine blood chemistry and metabolite markers were measured, along with lean muscle mass and body fat mass using body composition bioelectrical impedance analysis (BIA). Body mass index (BMI), body fat percentage (BFP), skeletal muscle mass index (SMI), and bone mineral density (BMD) were calculated for all individuals. For comparative analysis, individuals were grouped based on their BMI, BFP, SMI and BMD T-score. Follow-up examinations were performed in a cohort of 1,608 individuals matched for age, sex, smoking and drinking history for ≥5 years.

RESULTS

In this large cross-sectional study, age, smoking, homocysteine (Hcy) and blood glucose levels were established as independent risk factors for osteoporosis. Multi-factor logistic regression analysis showed that age, sex, BMI, intact parathyroid hormone (iPTH), SMI, BFP, smoking, blood levels of inorganic phosphate (P) and K+ were all significantly associated with osteoporosis risk (P<0.05). A subset of these factors- BMI, SMI, BFP and K+, were determined to be protective. In the cohort followed for ≥5 years, SMI and BMD decreased while BFP and BMI increased significantly (P<0.001) over time.

CONCLUSION

Risk of osteoporosis may be reduced by increasing body weight, particularly lean muscle mass, while simultaneously controlling BFP.

Serum chemerin levels: A potential biomarker of joint inflammation in women with rheumatoid arthritis

Background

Chemerin has a potential role in perpetuating inflammation in autoimmune diseases. Nevertheless, to date, there is no conclusive information on whether high chemerin levels increase the severity of rheumatoid arthritis (RA). Therefore, this study evaluated whether serum chemerin is a biomarker of disease activity in RA patients.

Methods

Study design: cross-sectional. The assessment included clinical and laboratory characteristics, body mass index (BMI) and fat mass. The severity of the disease activity was identified according to the DAS28-CRP index as follows: A) RA with a DAS28-CRP≤2.9 (remission/mild activity) and B) RA with a DAS28-CRP>2.9 (moderate/severe activity). Serum chemerin concentrations were measured by ELISA, and ≥103 ng/mL was considered a high level. Logistic regression analysis was applied to determine whether high chemerin levels were associated with disease activity in RA after adjusting for confounders. Multiple regression analysis was performed to identify variables associated with chemerin levels.

Results

Of 210 RA patients, 89 (42%) subjects had moderate/severe disease activity and had higher serum chemerin levels than patients with low disease activity or remission (86 ± 34 vs 73± 27; p = 0.003). Serum chemerin correlated with the number of swollen joints (r = 0.15; p = 0.03), DAS28-CRP (r = 0.22; p = 0.002), and C-reactive protein levels (r = 0.14; p = 0.04), but no correlation was observed with BMI and fat mass. In the adjusted logistic regression analysis, high chemerin levels (≥103 ng/mL) were associated with an increased risk of moderate/severe disease activity (OR: 2.76, 95% CI 1.35–5.62; p = 0.005). In the multiple regression analysis, after adjusting for potential confounders, serum chemerin levels were associated with higher DAS28-CRP (p = 0.002).

Conclusions

Higher chemerin levels increased the risk of moderate and severe disease activity in RA. These results support the role of chemerin as a marker of inflammation in RA. Follow-up studies will identify if maintaining low chemerin levels can be used as a therapeutic target.