Serum lncRNA ITGB2-AS1 and ICAM-1 as novel biomarkers for rheumatoid arthritis and osteoarthritis diagnosis.

BACKGROUND: The complete circulating long non-coding RNAs (lncRNAs) signature of rheumatoid arthritis (RA) and osteoarthritis (OA) is still uncovered. The lncRNA integrin subunit beta 2 (ITGB2)-anti-sense RNA 1 (ITGB2-AS1) affects ITGB2 expression; however, there is a gap in knowledge regarding its expression and clinical usefulness in RA and OA. This study investigated the potential of serum ITGB2-AS1 as a novel diagnostic biomarker and its correlation with ITGB2 expression and its ligand intercellular adhesion molecule-1 (ICAM-1), disease activity, and severity in RA and primary knee OA patients. SUBJECTS: Forty-three RA patients, 35 knee OA patients, and 22 healthy volunteers were included. RESULTS: Compared with healthy controls, serum ITGB2-AS1 expression was upregulated in RA patients but wasn't significantly altered in knee OA patients, whereas serum ICAM-1 protein levels were elevated in both diseases. ITGB2-AS1 showed discriminative potential for RA versus controls (AUC = 0.772), while ICAM-1 displayed diagnostic potential for both RA and knee OA versus controls (AUC = 0.804, 0.914, respectively) in receiver-operating characteristic analysis. In the multivariate analysis, serum ITGB2-AS1 and ICAM-1 were associated with the risk of developing RA, while only ICAM-1 was associated with the risk of developing knee OA. A panel combining ITGB2-AS1 and ICAM-1 showed profound diagnostic power for RA (AUC = 0.9, sensitivity = 86.05%, and specificity = 91.67%). Interestingly, serum ITGB2-AS1 positively correlated with disease activity (DAS28) in RA patients and with ITGB2 mRNA expression in both diseases, while ICAM-1 positively correlated with ITGB2 expression in knee OA patients. CONCLUSION: Our study portrays serum ITGB2-AS1 as a novel potential diagnostic biomarker of RA that correlates with disease activity. A predictive panel combining ITGB2-AS1 and ICAM-1 could have clinical utility in RA diagnosis. We also spotlight the association of ICAM-1 with knee OA diagnosis. The correlation of serum ITGB2-AS1 with ITGB2 expression in both diseases may be insightful for further mechanistic studies.

The volumes of amygdala subregions and peripheral programmed cell death protein-1 levels are associated with cognitive decline in individuals with knee osteoarthritis.

BACKGROUND: Persistent pain is a prominent symptom of knee osteoarthritis (KOA) and has been associated with cognitive decline in individuals with KOA. The amygdala, a complex structure consisting of nine subnuclei, and programmed cell death protein-1 (PD-1) levels play crucial roles in pain regulation and cognitive processing. This study aims to investigate the relationships among amygdala subregion volumes, cognitive function, and PD-1 levels to elucidate the underlying mechanism of cognitive decline in KOA. METHODS: In this cross-sectional study, we recruited 36 patients with KOA and 25 age/gender-matched healthy controls for neuropsychological tests, structural magnetic resonance imaging scanning, and measurement of serum PD-1 levels. We used the atlas provided by FreeSurfer software to automatically segment the amygdala subnuclei. Subsequently, we compared the volumes of amygdala subregions between groups and explored their correlation with clinical scores and PD-1 levels. RESULTS: Compared to healthy controls, individuals with KOA exhibited significantly lower scores on global cognition tasks, such as long-delay free recall, short-delay free recall, and immediate recall tasks. Moreover, they displayed decreased volumes in lateral nucleus basal nucleus paralaminar nucleus while showing increased volumes in accessory basal nucleus, central nucleus, medial nucleus, and cortical nucleus. Within the KOA group specifically, paralaminar volume was negatively correlated with immediate recall scores; pain scores were negatively correlated with global cognition; basal volume was negatively correlated with PD-1 levels. CONCLUSION: Our findings highlight those alterations in amygdala subregion volumes along with changes in serum PD-1 levels may contribute to observe cognitive decline among individuals suffering from KOA.

Vitamin D Deficiency after Anterior Cruciate Ligament Reconstruction Associates with Knee Osteoarthritis: A Retrospective Study.

BACKGROUND/OBJECTIVES: The objective of this study was to test the hypothesis that vitamin D deficiency (i.e., serum 25-hydroxyvitamin D (25(OH)D) ≤ 20 ng/mL) associates with the increased occurrence and shortened time to a knee osteoarthritis (OA) diagnosis after anterior cruciate ligament reconstruction (ACLR). METHODS: This study consisted of a retrospective, case-control design. The inclusion criteria consisted of (1) patients (≥18 y) who underwent arthroscopic ACLR with (cases; n = 28) and without (controls; n = 56) a subsequent knee OA diagnosis (≥90 d from the date of ACLR) and (2) with a documented serum 25(OH)D concentration after ACLR (and before a knee OA diagnosis for the cases). Controls were matched (2:1) to cases based on sex, age at ACLR, date of ACLR, and body mass index. After matching, patients were separated into two groups: (1) vitamin D deficient (serum 25(OH)D ≤ 20 ng/mL) or (2) non-vitamin D deficient (serum 25(OH)D > 20 ng/mL). Data were extracted from the medical records. RESULTS: Thirty-one percent (n = 26) of patients included were vitamin D deficient. Fifty percent (n = 13) of the vitamin D deficient and twenty-six percent (n = 15) of the non-vitamin D deficient patients were subsequently diagnosed with knee OA (p = 0.03). Time from ACLR to a knee OA diagnosis was significantly (p = 0.02) decreased in the vitamin D deficient (OA-free interval, 95% confidence interval [CI] = 7.9 to 10.9 y) compared to the non-vitamin D deficient group (OA-free interval, 95% CI = 10.5 to 12.5 y). CONCLUSIONS: Vitamin D deficiency after ACLR may serve as a prognostic biomarker for knee OA following ACLR.

The Maximum Threshold Value for HbA1c in Diabetic Patients Undergoing Elective Total Knee Arthroplasty.

OBJECTIVE: To establish an optimal preoperative HbA1c threshold that enhances surgical outcomes and minimises postoperative complications in diabetic patients undergoing elective total knee arthroplasty (TKA). STUDY DESIGN: Prospective cohort study. Place and Duration of the Study: Department of Orthopaedics, First People's Hospital of Lianyungang, China, from January 2021 to March 2024. METHODOLOGY: A total of 152 diabetic patients scheduled for elective TKA were included. Data on preoperative HbA1c levels were collected and analysed to assess their impact on postoperative outcomes using the Oxford Knee Score (OKS). Patients were divided into groups based on HbA1c levels and compared for functional and pain recovery one year postoperatively. Statistical analyses included binary and multivariate logistic regression, with an emphasis on the minimum clinically important difference for OKS. RESULTS: Patients with a preoperative HbA1c below 7.35mmol/L exhibited significantly better functional and pain recovery outcomes at one-year post-TKA. The receiver operating characteristic curve (ROC) analysis confirmed the predictive power of HbA1c, with an Area Under the Curve of 0.734 for functional improvement and 0.721 for pain improvement. CONCLUSION: The study identifies 7.35mmol/L as the optimal preoperative HbA1c threshold for diabetic patients undergoing elective TKA, with lower levels associated with improved functional and pain outcomes. Maintaining HbA1c below this level preoperatively can significantly enhance postoperative recovery and patient satisfaction. KEY WORDS: Diabetes mellitus, Total knee arthroplasty, Haemoglobin A1c, Oxford knee score.

Study of adiponectin gene (rs1501299) polymorphism and serum adiponectin level in patients with primary knee osteoarthritis.

BACKGROUND: We aimed to study, for the first time in the Egyptian population, the relationship between the serum adiponectin level in knee osteoarthritis (KOA) patients and its correlation with clinical, radiological, and ultrasonographic characteristics. Additionally, investigate the relationship between the adiponectin (ADIPOQ) gene rs1501299 (+ 276G/T) polymorphism and KOA susceptibility and severity. METHODS: This case-control study enrolled 40 patients with primary KOA and 40 matched controls. All patients underwent physical examination of the knee, pain assessment using the visual analogue scale (VAS), and functional evaluation by Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Severity of KOA was assessed by Kellgren Lawrence (KL) grading scale and ultrasonography grading systems. Serum adiponectin levels and adiponectin (ADIPOQ) gene single nucleotide polymorphism (SNP) (rs1501299) genotyping were done for all patients and controls. RESULTS: The study included 40 patients with primary symptomatic KOA and 40 controls with comparable age, sex, and body mass index. The genotype of the rs1501299 (+ 276G/T) polymorphism of the ADIPOQ gene was determined using TaqMan allelic discrimination. An enzyme-linked immunosorbent test was used to measure the level of serum adiponectin. The Western Ontario and McMaster Universities Osteoarthritis (WOMAC) score was used to assess functional capability, while the visual analogue scale was utilised to assess knee pain. Using the Kellgren-Lawrence (KL) grading method and global femoral cartilage (GFC) ultrasound grading, the severity of KOA was assessed. No significant differences between patients and controls as regards the genotype distributions and allele frequencies (p = 0.400, p = 0.507, respectively) of ADIPOQ gene rs1501299 (+ 276G/T) polymorphism. Furthermore, serum adiponectin level was significantly higher in the patients compared to healthy subjects (p < 0.001). Additionally, adiponectin level had a significant negative correlation with disease severity as evaluated by KL and GFC grading (r=-0.351, p = 0.027 and r=-0.397, p = 0.011, respectively). CONCLUSIONS: The ADIPOQ gene rs1501299 (+ 276G/T) polymorphism was not associated with KOA severity or vulnerability. The level of adiponectin considerably reduced as the severity of KOA rose, indicating that adiponectin may have a preventive effect in KOA.

Effect of moxibustion on plasma amino acid metabolism in rats with knee osteoarthritis. / è‰¾ç¸å¯¹è†å ³èŠ‚éª¨å ³èŠ‚ç‚Žå¤§é¼ è¡€æµ†æ°¨åŸºé ¸ä»£è°¢çš„å½±å“.

OBJECTIVES: To observe the effect of moxibustion at "Zusanli "(ST36) on the plasma amino acid metabolism in rats with knee osteoarthritis (KOA), and to explore the amino acid metabolism mechanism of moxibustion in repairing cartilage injury in KOA. METHODS: A total of 30 SD rats were randomly divided into normal, model and moxibustion groups, with 10 rats in each group. Rats in the model and moxibustion groups were injected with the mixture of L-cysteine and papain into bilateral knee joint cavity to make the KOA model. The moxibustion group received moxibustion at bilateral ST36 for 30 min, once daily for 30 days. At the end of the experiment, the swelling degree of knee joint was calculated, the mechanical pain threshold was measured by the Von Frey filament, the cartilage tissue injury was observed by HE staining, the matrix metalloproteinase-13 (MMP-13) content in the synovial tissue was detected by enzyme-linked immunosorbent assay (ELISA), and the differential amino acid metabolites in plasma were detected and screened by liquid chromatography-mass spectrometry (LC-MS). RESULTS: Compared with the normal group, the model group showed irregular cartilage surface, decreased number of chondrocytes, uneven distribution, and local clusters of chondrocytes；the contour of the tide line was blurred. The degree of joint swelling in the model group was higher than that in the normal group (P<0.01), the mechanical pain threshold was lower (P<0.01), and the content of MMP-13 in synovial tissue was higher (P<0.01). The contents of proline and tryptophan in the model group were down-regulated (P<0.01, P<0.05). Compared with the model group, the cartilage tissue damage and knee joint swelling were decreased(P<0.05), mechanical pain threshold was increased(P<0.05), MMP-13 content in synovial tissue and levels of glutamate and histidine expression were decreased (P<0.01, P<0.05). CONCLUSIONS: Moxibustion at ST36 significantly alleviated arthritis-related swelling and pain in KOA model rats, attenuated cartilage damage, and regulated levels of certain plasma amino acid metabolites. Moxibustion may regulate KOA cartilage synthesis and degradation through amino acid metabolic pathways such as proline, tryptophan, glutamate and histidine, exerting anti-inflammatory, analgesic, and protection of cartilage injury effects.

Identification of novel drug targets for osteoarthritis by integrating genetics and proteomes from blood.

BACKGROUND: Osteoarthritis (OA) is a degenerative osteoarticular disease, involving genetic predisposition. How the risk variants confer the risk of OA through their effects on proteins remains largely unknown. Therefore, we aimed to discover new and effective drug targets for OA and its subtypes. METHODS: A proteome-wide association study (PWAS) was performed based on OA and its subtypes genome-wide association studies (GWAS) summary datasets and the protein quantitative trait loci (pQTL) data. Subsequently, Mendelian randomization (MR) and colocalization analysis was conducted to estimate the associations between protein and OA risk. The replication analysis was performed in an independent dataset of human plasma pQTL data. RESULTS: The abundance of seven proteins was causally related to OA, two proteins to knee OA and six proteins to hip OA, respectively. We replicated 2 of these proteins using an independent pQTL dataset. With the further support of colocalization, and higher ECM1 level was causally associated with a higher risk of OA and hip OA. Higher PCSK1 level was causally associated with a lower risk of OA. And higher levels of ITIH1, EFEMP1, and ERLEC1 were associated with decreased risk of hip OA. CONCLUSION: Our study provides new insights into the genetic component of protein abundance in OA and a promising therapeutic target for future drug development.

Association between Low Serum Creatinine Levels and Knee Osteoarthritis in Koreans without Renal Insufficiency.

PURPOSE: This study aimed to investigate the correlation between serum creatinine levels and the presence and severity of radiographic knee osteoarthritis (OA) in individuals aged ≥50 years while adjusting for potential confounders. MATERIALS AND METHODS: Cross-sectional data from the 2009-2011 Korea National Health and Nutrition Examination Survey comprising 3428 individuals aged ≥50 years were utilized. The Kellgren-Lawrence (K-L) grading scale was used to assess the radiographic presence and severity of knee OA. Logistic regression and receiver operating characteristic analyses were used to investigate the association between serum creatinine levels and the presence of knee OA, whereas ordinal regression was used to assess the impact of creatinine levels on knee OA severity. RESULTS: The presence of radiographic knee OA conferred by low serum creatinine levels was found to be significant in both sexes [odds ratio (OR), 0.118; 95% confidence interval (CI), 0.045-0.314, p<0.001 for men; OR, 0.148; 95% CI, 0.040-0.549, p=0.004 for women]. Low serum creatinine was significantly associated with knee OA-graded K-L severity in each sex-based group [ß, -1.923; standard error, 0.478; p<0.001 for men and ß, -1.532; SE, 0.575; p=0.008 for women]. CONCLUSION: Low serum creatinine level was associated with a higher presence of knee OA in both men and women, and was also linked to the severity of the disease. These findings suggest that the serum creatinine level may be a potential biomarker for assessing the presence and severity of knee OA.

Association of serum and synovial adipokines (chemerin and resistin) with inflammatory markers and ultrasonographic evaluation scores in patients with knee joint osteoarthritis- a pilot study.

Chemerin and resistin are adipokines studied as potential markers for early diagnosis and disease severity in patients with knee osteoarthritis (KOA) Therefore, we aimed to investigate the associations serum and synovial levels of chemerin and resistin with inflammatory parameters and ultrasonographic scores (US) in KOA individuals. Serum was collected from 28 patients with KOA and synovial fluid was obtained from 16 of them. Another 31 age and sex matched cases with no joint disease were included as healthy controls. Concentrations of chemerin, resistin, interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-alpha) were determined with ELISA. Erythrocyte sedimentation rate (ESR), C-reactive protein, serum uric acid (UA) were measured in the patients group. Participants with KOA underwent US assessment using the Outcome Measures in Rheumatology (OMERACT) scores. Patients with KOA had statistically significant higher level of serum resistin than healthy controls [11.05 (3.78-24.13) ng/mL and 7.23 (3.83-12.19) respectively, p < 0.001]. A strong correlation was found between serum chemerin and ESR (r = 0.434, p = 0.021), uric acid (r = 0.573, p = 0.001) as well as the US (r=-0.872, p < 0.001). Serum resistin demonstrated significant association with TNF-alpha (r = 0.398, p = 0.044). In conclusion, both chemerin and resistin might contribute to inflammatory changes associated with KOA. Further studies are needed to elucidate their potential role in the pathogenesis of the disease.

Machine learning analysis of serum cholesterol's impact on knee osteoarthritis progression.

The controversy surrounding whether serum total cholesterol is a risk factor for the graded progression of knee osteoarthritis (KOA) has prompted this study to develop an authentic prediction model using a machine learning (ML) algorithm. The objective was to investigate whether serum total cholesterol plays a significant role in the progression of KOA. This cross-sectional study utilized data from the public database DRYAD. LASSO regression was employed to identify risk factors associated with the graded progression of KOA. Additionally, six ML algorithms were utilized in conjunction with clinical features and relevant variables to construct a prediction model. The significance and ranking of variables were carefully analyzed. The variables incorporated in the model include JBS3, Diabetes, Hypertension, HDL, TC, BMI, SES, and AGE. Serum total cholesterol emerged as a significant risk factor for the graded progression of KOA in all six ML algorithms used for importance ranking. XGBoost algorithm was based on the combined best performance of the training and validation sets. The ML algorithm enables predictive modeling of risk factors for the progression of the KOA K-L classification and confirms that serum total cholesterol is an important risk factor for the progression of KOA.

Association of Serum Biochemical Biomarker Profiles of Joint Tissue Inflammation and Cartilage Metabolism With Posttraumatic Osteoarthritis-Related Symptoms at 12 Months After ACLR.

BACKGROUND: Anterior cruciate ligament injury and anterior cruciate ligament reconstruction (ACLR) are risk factors for symptomatic posttraumatic osteoarthritis (PTOA). After ACLR, individuals demonstrate altered joint tissue metabolism indicative of increased inflammation and cartilage breakdown. Serum biomarker changes have been associated with tibiofemoral cartilage composition indicative of worse knee joint health but not with PTOA-related symptoms. PURPOSE/HYPOTHESIS: The purpose of this study was to determine associations between changes in serum biomarker profiles from the preoperative sample collection to 6 months after ACLR and clinically relevant knee PTOA symptoms at 12 months after ACLR. It was hypothesized that increases in biomarkers of inflammation, cartilage metabolism, and cartilage degradation would be associated with clinically relevant PTOA symptoms after ACLR. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: Individuals undergoing primary ACLR were included (N = 30). Serum samples collected preoperatively and 6 months after ACLR were processed to measure markers indicative of changes in inflammation (ie, monocyte chemoattract protein 1 [MCP-1]) and cartilage breakdown (ie, cartilage oligomeric matrix protein [COMP], matrix metalloproteinase 3, ratio of type II collagen breakdown to type II collagen synthesis). Knee injury and Osteoarthritis Outcome Score surveys were completed at 12 months after ACLR and used to identify participants with and without clinically relevant PTOA-related symptoms. K-means cluster analyses were used to determine serum biomarker profiles. One-way analyses of variance and logistic regressions were used to assess differences in Knee injury and Osteoarthritis Outcome Score subscale scores and clinically relevant PTOA-related symptoms between biomarker profiles. RESULTS: Two profiles were identified and characterized based on decreases (profile 1: 67% female; age, 21.4 ± 5.1 years; body mass index, 24.4 ± 2.4) and increases (profile 2: 33% female; age, 21.3 ± 3.2 years; body mass index, 23.4 ± 2.6) in sMCP-1 and sCOMP preoperatively to 6 months after ACLR. Participants with profile 2 did not demonstrate differences in knee pain, symptoms, activities of daily living, sports function, or quality of life at 12 months after ACLR compared to those with profile 1 (P = .56-.81; η2 = 0.002-0.012). No statistically significant associations were noted between biomarker profiles and clinically relevant PTOA-related symptoms (odds ratio, 1.30; 95% CI, 0.23-6.33). CONCLUSION: Serum biomarker changes in MCP-1 and sCOMP within the first 6 months after ACLR were not associated with clinically relevant PTOA-related symptoms.

Genetic insights into serum cathepsins as diagnostic and therapeutic targets in knee and hip osteoarthritis.

Osteoarthritis (OA) is a chronic disease due to the deterioration of cartilage structure and function, involving the progressive degradation of the cartilage extracellular matrix. Cathepsins, lysosomal cysteine proteases, play pivotal roles in various biological and pathological processes, particularly in protein degradation. Excess cathepsins levels are reported to contribute to the development of OA. However, the causal relationship between the cathepsin family and knee and hip OA remains uncertain. Therefore, this study utilized bidirectional Mendelian Randomization (MR) analyses to explore this causal association. Our results indicated that elevated serum levels of cathepsin O increase the overall risk of knee OA, while increased serum levels of cathepsin H enhance the risk of hip OA. Conversely, the reverse MR analyses did not reveal a reverse causal relationship between them. In summary, OA in different anatomical locations may genetically result from pathological elevations in different serum cathepsin isoforms, which could be utilized as diagnostic and therapeutic targets in clinical practice.

Dietary and serum antioxidant capacity is inversely associated with patients in osteoarthritis: a case-control study.

This study aimed to examine dietary antioxidant and serum antioxidant capacity in patients with knee osteoarthritis (OA). This case-control study consisted of 47 patients with OA (case group) and 30 healthy subjects (control group). The control and case group were matched age, gender, and body mass index (p > 0.05). A food frequency questionnaire was administered to participants, and dietary total antioxidant capacity (DTAC) was estimated using the ferric reducing antioxidant power method (FRAP). Participants' serum total antioxidant capacity (TAC) and total oxidant capacity (TOC) measurements were performed, and the oxidative stress index (OSI) was calculated. DTAC of case group was found to be lower than the control group (p < 0.05). The daily consumption of red meat and butter of the individuals in the case group was higher than that of the control group, and their fish consumption, dietary vitamin A and carotene intakes were found to be lower (p < 0.05). In addition, OA patients have TAC and OSI was also found to be significantly higher than in control group (p = 0.001 and p < 0.001). Since low dietary total antioxidant capacity and high serum total oxidant capacity, individuals with OA should pay more attention to their diet to increase serum antioxidant status.

Preoperative Laboratory Values Predicting Periprosthetic Joint Infection in Morbidly Obese Patients Undergoing Total Hip or Knee Arthroplasty.

BACKGROUND: Morbidly obese patients are an ever-growing high-risk population undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA) for end-stage osteoarthritis. This study sought to identify preoperative laboratory values that may serve as predictors of periprosthetic joint infection (PJI) in morbidly obese patients undergoing THA or TKA. METHODS: All morbidly obese patients with preoperative laboratory data before undergoing primary elective TKA or THA were identified using the Premier Healthcare Database. Patients who developed PJI within 90 days after surgery were compared with patients without PJI. Laboratory value thresholds were defined by clinical guidelines or primary literature. Univariate and multivariable regression analyses were utilized to assess the association between PJI and preoperative laboratory values, including total lymphocyte count, neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), monocyte-lymphocyte ratio (MLR), systemic immune-inflammation index (SII), albumin level, platelet count, albumin-globulin ratio, hemoglobin level, and hemoglobin A1c. RESULTS: Of the 6,780 patients identified (TKA: 76.67%; THA: 23.33%), 47 (0.69%) developed PJI within 90 days after surgery. The rate of PJI was 1.69% for patients with a hemoglobin level of <12 g/dL (for females) or <13 g/dL (for males), 2.14% for those with a platelet count of <142,000/µL or >417,000/µL, 1.11% for those with an NLR of >3.31, 1.69% for those with a PLR of >182.3, and 1.05% for those with an SII of >776.2. After accounting for potential confounding factors, we observed an association between PJI and an abnormal preoperative NLR (adjusted odds ratio [aOR]: 2.38, 95% confidence interval [CI]: 1.04 to 5.44, p = 0.039), PLR (aOR: 4.86, 95% CI: 2.15 to 10.95, p < 0.001), SII (aOR: 2.44, 95% CI: 1.09 to 5.44, p = 0.029), platelet count (aOR: 3.50, 95% CI: 1.11 to 10.99, p = 0.032), and hemoglobin level (aOR: 2.62, 95% CI: 1.06 to 6.50, p = 0.038). CONCLUSIONS: This study identified preoperative anemia, abnormal platelet count, and elevated NLR, PLR, and SII to be associated with an increased risk of PJI among patients with a body mass index of ≥40 kg/m 2 . These findings may help surgeons risk-stratify this high-risk patient population. LEVEL OF EVIDENCE: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Elevated proinflammatory cytokines in response to mechanical stimulus are associated with reduced knee loading 2 years after anterior cruciate ligament reconstruction.

BACKGROUND: The aim of this study was to test the hypothesis that proinflammatory cytokines correlate with knee loading mechanics during gait following a mechanical walking stimulus in subjects 2 years after anterior cruciate ligament reconstruction. Elevated systemic levels of proinflammatory cytokines can be sustained for years after injury. Considering roughly 50% of these patients progress to Osteoarthritis 10-15 years after injury, a better understanding of the role of proinflammatory cytokines such as tumor necrosis factor-α and Interleukin-1ß on Osteoarthritis risk is needed. METHODS: Serum proinflammatory cytokines concentrations were measured in 21 subjects 2 years after unilateral ACLR from blood drawn at rest and 3.5 h after 30 min of walking. An optoelectronic system and a force plate measured subjects' knee kinetics. Correlations were tested between inflammatory marker response and knee extension and knee adduction moments. FINDINGS: Changes in proinflammatory cytokines due to mechanical stimulus were correlated (R = 0.86) and showed substantial variation between subjects in both cytokines at 3.5 h post-walk. Knee loading correlated with 3.5-h changes in tumor necrosis factor-α concentration (Knee extension moment: R = -0.5, Knee adduction moment: R = -0.5) and Interleukin-1ß concentration (Knee extension moment: R = -0.44). However, no significant changes in concentrations were observed in tumor necrosis factor-α and Interleukin-1ß when comparing baseline and post walking stimulus conditions. INTERPRETATION: The significant associations between changes in serum proinflammatory markers following a mechanical stimulus and gait metrics in subjects at risk for developing Osteoarthritis underscore the importance of investigating the interaction between biomarkers and biomechanical factors in Osteoarthritis development.

Two-year post-distraction cartilage-related structural improvement is accompanied by increased serum full-length SIRT1.

BACKGROUND: Previously, fragments from Sirtuin 1 (SIRT1) were identified in preclinical and clinical samples to display an increase in serum levels for N-terminal (NT) SIRT1 vs. C-terminal (CT) SIRT1, indicative of early signs of OA. Here we tested NT/CT SIRT1 levels as well as a novel formulated sandwich assay to simultaneously detect both domains of SIRT1 in a manner that may inform us about the levels of full-length SIRT1 in the circulation (flSIRT1) of clinical cohorts undergoing knee joint distraction (KJD). METHODS: We employed an indirect ELISA assay to test NT- and CT-SIRT1 levels and calculated their ratio. Further, to test flSIRT1 we utilized novel antibodies (Ab), which were validated for site specificity and used in a sandwich ELISA method, wherein the CT-reactive served as capture Ab, and its NT-reactive served as primary detection Ab. This method was employed in human serum samples derived from a two-year longitudinal study of KJD patients. Two-year clinical and structural outcomes were correlated with serum levels of flSIRT1 compared to baseline. RESULTS: Assessing the cohort, exhibited a significant increase of NT/CT SIRT1 serum levels with increased osteophytes and PIIANP/CTX-II at baseline, while a contradictory increase in NT/CT SIRT1 was associated with less denuded bone, post-KJD. On the other hand, flSIRT1 exhibited an upward trend in serum level, accompanied by reduced denuded bone for 2-year adjusted values. Moreover, 2 year-adjusted flSIRT1 levels displayed a steeper linear regression for cartilage and bone-related structural improvement than those observed for NT/CT SIRT1. CONCLUSIONS: Our data support that increased flSIRT1 serum levels are a potential molecular endotype for cartilage-related structural improvement post-KJD, while NT/CT SIRT1 appears to correlate with osteophyte and PIIANP/CTX-II reduction at baseline, to potentially indicate baseline OA severity.

Circulating cytokines levels and osteoarthritis: A Mendelian randomization study.

BACKGROUND: Previous traditional observational studies have suggested the contribution of several cytokines and growth factors to the development of osteoarthritis (OA). This study aimed to determine the association of circulating cytokine and growth factor levels with OA. METHODS: We used two-sample Mendelian randomization (MR) to explore the causality between circulating cytokine and growth factor levels and OA [including knee or hip OA (K/HOA), knee OA (KOA), and hip OA (HOA)]. Summary level data for circulating cytokine and growth factor levels were sourced from a genome-wide association study (GWAS) involving 8,293 participants of Finnish ancestry. Single-nucleotide polymorphisms related to K/HOA (39,427 cases and 378,169 controls), KOA (24,955 cases and 378,169 controls), and HOA (15,704 cases and 378,169 controls) were obtained from a previous GWAS. The inverse variance weighted (IVW) method was primarily used for our MR analysis. For exposures to only one relevant SNP as IV, we used the Wald ratio as the major method to assess causal effects. We also conducted a series of sensitivity analyses to improve the robustness of the results. RESULTS: Circulating vascular endothelial growth factor levels were suggestively associated with an increased risk of K/HOA (odds ratio (OR) = 1.034; 95 % confidence interval (CI) = 1.013-1.055; P = 0.001), KOA (OR = 1.034; 95 % CI = 1.014-1.065; P = 0.002), and HOA (OR = 1.039; 95 % CI = 1.003-1.067; P = 0.034). Circulating interleukin (IL)-12p70 levels was suggestively associated with K/HOA (OR = 1.047; 95 % CI = 1.018-1.077; P = 0.001), KOA (OR = 1.058; 95 % CI = 1.022-1.095; P = 0.001), and HOA (OR = 1.044; 95 % CI = 1.000-1.091; P = 0.048). Circulating IL-18 levels were suggestively associated with HOA (OR = 1.068; 95 % CI = 1.014-1.125; P = 0.012). However, limited evidence exists to support causal genetic relationships between other circulating cytokines, growth factor levels and K/HOA, KOA, and HOA. CONCLUSIONS: Our MR analysis provides suggestive evidence of causal relationships between circulating cytokines and growth factors levels and OA, providing new insights into the etiology of OA.

Serum levels of hydroxylated metabolites of arachidonic acid cross-sectionally and longitudinally predict knee pain progression: an observational cohort study.

OBJECTIVE: To examine associations between serum oxylipins, which regulate tissue repair and pain signalling, and knee pain/radiographic osteoarthritis (OA) at baseline and knee pain at 3 year follow-up. METHOD: Baseline, and 3 year follow-up, knee pain phenotypes were assessed from 154 participants in the Knee Pain in the Community (KPIC) cohort study. Serum and radiographic Kellgren and Lawrence (KL) and Nottingham line drawing atlas OA scores were collected at baseline. Oxylipin levels were quantified using liquid chromatography coupled with mass spectrometry. Associations were measured by linear regression and receiver operating characteristics (ROC). RESULTS: Serum levels of 8,9-epoxyeicosatrienoic acid (EET) (ß(95% confidence intervals (CI)) = 1.809 (-0.71 to 2.91)), 14,15-dihydroxyeicosatrienoic acid (DHET) (ß(95%CI) = 0.827 (0.34-1.31)), and 12-hydroxyeicosatetraenoic acid (HETE) (ß(95%CI) = 4.090 (1.92-6.26)) and anandamide (ß(95%CI) = 3.060 (1.35-4.77)) were cross-sectionally associated with current self-reported knee pain scores (numerical rating scale (NRS) item 3, average pain). Serum levels of 9- (ß(95%CI) = 0.467 (0.18-0.75)) and 15-HETE (ß(95%CI) = 0.759 (0.29-1.22)), 14-hydroxydocosahexaenoic acid (ß(95%CI) = 0.483(0.24-0.73)), and the ratio of 8,9-EET:DHET (ß(95%CI) = 0.510(0.19-0.82)) were cross-sectionally associated with KL scores. Baseline serum concentrations of 8,9-EET (ß(95%CI) = 2.166 (0.89-3.44)), 5,6-DHET (ß(95%CI) = 152.179 (69.39-234.97)), and 5-HETE (ß(95%CI) = 1.724 (0.677-2.77) showed positive longitudinal associations with follow-up knee pain scores (NRS item 3, average pain). Combined serum 8,9-EET and 5-HETE concentration showed the strongest longitudinal association (ß(95%CI) = 1.156 (0.54-1.77) with pain scores at 3 years, and ROC curves distinguished between participants with no pain and high pain scores at follow-up (area under curve (95%CI) = 0.71 (0.61-0.82)). CONCLUSIONS: Serum levels of a combination of hydroxylated metabolites of arachidonic acid may have prognostic utility for knee pain, providing a potential novel approach to identify people who are more likely to have debilitating pain in the future.

Analysis of the Level of Adiponectin and Selected Cytokines in Patients with Knee Osteoarthritis.

Background and Objectives: Knee osteoarthritis (KOA) is a degenerative disease that is continuously targeting people of different ages, but especially the elderly population, the number of which tends to increase continuously at the global level. Apart from age, excess weight can influence the evolution of the disease, with obesity being associated with a weak inflammation stage and an imbalance between pro-inflammatory and anti-inflammatory cytokines. The present work aimed to analyze specific biomarkers, namely ACRP-30, IL-10, TNF-α, and IL-6, in knee synovial fluid, and correlate them with KOA patients' clinical data, radiographic changes, and functional and pain scores. Materials and Methods: 24 subjects with KOA and over 50 years of age participate in the present study. Synovial fluid was harvested using ultrasound guidance from the target knees of the enrolled KOA patients, and the levels of ACRP-30, IL-10, TNF-α, and IL-6 were measured using enzyme-linked immunosorbent assays (ELISA). All patients underwent a supine X-ray at the target knee and were classified using Kellgren-Lawrence (K-L) grading. The Western Ontario and McMaster University Osteoarthritis Index (WOMAC) was used to assess self-reported physical function, pain, and stiffness. Results: The obtained results highlighted a significant correlation between age and adiponectin level (p = 0.0451, r = -0.412). Also, the IL-10 values are lower in cases where the intensity of the pain is more pronounced (p = 0.0405, r = -0.421). In addition, analyzing the data by gender, it was observed that in the case of males, stiffness is more related to age (p = 0.0079, r = 0.7993), compared to women (p = 0.0203, r = 0.6223). In the case of women, the progression of the disease tends to increase more intensively the WOMAC score's total values (p = 0.00031, r = 0.8342), compared with men (p = 0.0289, r = 7013). Regarding interleukins and BMI, significant correlations were observed only in the case of men. Conclusions: A significant correlation between age and adiponectin, and adiponectin and IL-6, suggests that advanced age may contribute to adiponectin reduction. Comparing men with women, it was observed that men's age is more related to rigidity, and IL-6 and IL-10 are directly correlated to BMI; in addition, women seem to be more sensitive to pain and stiffness.

Fatty Acid Intake and Polyunsaturated Fatty Acid Biomarkers and Risk of Total Knee or Hip Arthroplasty Among Older Women in the Women's Health Initiative.

OBJECTIVE: The objective was to determine whether baseline fatty acid intake and erythrocyte omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) can predict risk of total hip arthroplasty (THA) and total knee arthroplasty (TKA) in older women. METHODS: This was a prospective analysis of 34,990 women in the Women's Health Initiative. Dietary fatty acids were estimated from food frequency questionnaires. Imputed erythrocyte PUFAs were available in a subcohort of 3,428 women. Arthroplasty (THA and TKA), used as a surrogate of severe osteoarthritis, was identified via linked Medicare data. Cox proportional hazards models were constructed to estimate risk of arthroplasty. RESULTS: Risk of THA was associated with higher intake of arachidonic acid, (multivariable hazard ratio [HR] quartile 4 [Q4] vs Q1: 1.16; 95% confidence interval [CI] 1.01-1.34; P = 0.03) and higher intake of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA; HR Q4 vs Q1: 1.20; 95% CI 1.05-1.39; P = 0.003). There was a linear trend (P = 0.04) for patients to have a higher risk of THA with higher erythrocyte EPA and DHA in body mass index-adjusted models; however, there was no significant difference in patients who had THAs by quartiles of erythrocyte EPA and DHA (P = 0.10). Dietary fatty acids and erythrocyte PUFAs were not significantly associated with risk of TKA. CONCLUSION: Higher baseline intakes of arachidonic acid and EPA and DHA were associated with a modestly higher risk of THA. No association was found between fatty acids and patients who had TKAs. Further research in populations with direct measures of osteoarthritis severity is needed to better understand the importance of PUFAs in modulating osteoarthritis and arthroplasty risk.