Inflammatory Marker Changes Following Total Knee Arthroplasty for Rheumatoid Arthritis with Vancomycin-loaded Calcium Sulfate Bone Filling.

Rheumatoid arthritis (RA) patients undergoing total knee arthroplasty (TKA) face infection risk. The study evaluates vancomycin-loaded calcium sulfate bone as infection prevention. Patients with RA treated with TKA who had their femoral canal filled using either vancomycin-loaded calcium sulfate bone (experimental group [n = 35]) or the patient's own excised autologous bone (control group [n = 30]) at the Qingdao University Affiliated Hospital, Qingdao, China from January 1, 2017, to March 1, 2023, were retrospectively enrolled in this study. An experienced surgeon used midvastus approach. Surgeries included disinfection, antibiotics, and femoral filling. The age, gender, body mass index (BMI), comorbidities, and intraoperative details were extracted from the patient's medical records. Preoperation and postoperation markers (C-reactive protein [CRP], erythrocyte sedimentation rate [ESR]), pain scale (Visual Analog Scale [VAS]), infection rate, and Knee Society Score (KSS) were collected. Groups matched in age, gender, and BMI. No preoperative inflammatory marker differences were observed. However, compared to the control group, the postoperative inflammatory markers were significantly lower in the experimental group at 1-week postsurgery (CRP: 40.80 ± 23.17 vs. 60.80 ± 43.12 mg/L, p = 0.021; ESR: 72.06 ± 17.52 vs. 83.87 ± 21.52 mm/h, p = 0.012) and at 1-month postsurgery (CRP: 15.63 ± 6.56 vs. 21.17 ± 13.16 mg/L, p = 0.032; ESR: 25.25 ± 20.44 vs. 38.40 ± 25.26 mm/h, p = 0.024). There were no significant differences in the VAS (2.79 ± 0.90 vs. 2.70 ± 0.84 score, p = 0.689) and KSS (64.31 ± 17.88 vs. 66.57 ± 12.36) at 1-month postsurgery. Experimental group: zero infections; control group: only one infection. Administering vancomycin and calcium sulfate during TKA in RA patients reduces postoperative inflammation, but does not significantly affect infection risk; further research may be necessary for validation.

Research progress on macrophage polarization during osteoarthritis disease progression: a review.

Primary osteoarthritis (OA) is a prevalent degenerative joint disease that mostly affects the knee joint. It is a condition that occurs around the world. Because of the aging population and the increase in obesity prevalence, the incidence of primary OA is increasing each year. Joint replacement can completely subside the pain and minimize movement disorders caused by advanced OA, while nonsteroidal drugs and injection of sodium hyaluronate into the joint cavity can only partially relieve the pain; hence, it is critical to search for new methods to treat OA. Increasing lines of evidence show that primary OA is a chronic inflammatory disorder, with synovial inflammation as the main characteristic. Macrophages, as one of the immune cells, can be polarized to produce M1 (proinflammatory) and M2 (anti-inflammatory) types during synovial inflammation in OA. Following polarization, macrophages do not come in direct contact with chondrocytes; however, they affect chondrocyte metabolism through paracrine production of a significant quantity of inflammatory cytokines, matrix metalloproteinases, and growth factors and thus participate in inducing joint pain, cartilage injury, angiogenesis, and osteophyte formation. The main pathways that influence the polarization of macrophages are the Toll-like receptor and NF-κB pathways. The study of how macrophage polarization affects OA disease progression has gradually become one of the approaches to prevent and treat OA. Experimental studies have found that the treatment of macrophage polarization in primary OA can effectively relieve synovial inflammation and reduce cartilage damage. The present article summarizes the influence of inflammatory factors secreted by macrophages after polarization on OA disease progression, the main signaling pathways that induce macrophage differentiation, and the role of different polarized types of macrophages in OA; thus, providing a reference for preventing and treating primary OA.

Simultaneous bilateral open wedge high tibial osteotomy versus simultaneous bilateral unicompartmental knee arthroplasty in the treatment of bilateral medial knee osteoarthritis: a retrospective study of an average three-year follow-up.

OBJECTIVE: There is growing evidence that simultaneous bilateral open wedge high tibial osteotomy(SBOWHTO) and simultaneous bilateral unicompartmental knee arthroplasty(SBUKA) is an effective surgical treatment for bilateral medial knee osteoarthritis (MKOA). However, which intervention is more beneficial for bilateral MKOA patients remains unknown. Therefore, the aim of this study was to compare the effectiveness of these two strategies through early clinical outcomes, complication rates, and prosthetic survival. METHODS: The clinical data of 60 patients with bilateral MKOA admitted to the Affiliated Hospital of Qingdao University from January 2018 to December 2022 were retrospectively analyzed, and they were divided into SBOWHTO group (n = 28) and SBUKA group (n = 32) according to different treatment methods. Clinical relevant indexes, Hospital for Special Surgery (HSS) score, Knee Society Knee (KSS) score, range of motion(ROM), postoperative complications and prosthetic survival rate were compared between the two groups. RESULTS: Patients in the SBOWHTO group were followed up for 27 to 50 months, with an average of (37.18 ± 6.84) months. Patients in the SBUKA group were followed up for 24 to 59 months, with an average of (39.38 ± 9.74) months. There were no significant differences in postoperative KSS, HSS and ROM between SBOWHTO group and SBUKA group (p > 0.05). There was no significant difference in complication rate between the two groups (p = 0.721). There was no significant difference in prosthetic survival rate (p = 0.622) and prosthetic survival curve (χ2 = 0.546, p = 0.46) between the two groups. CONCLUSIONS: This study compared early clinical outcomes, complication rates, and prosthesis retention rates after SBOWHTO and SBUKA, and found that the early clinical benefits of SBOWHTO and SBUKA were comparable in patients with bilateral MKOA.

New insights on the phylogeny, evolutionary history, and ecological adaptation mechanism in cycle-cup oaks based on chloroplast genomes.

Cycle-cup oaks (Quercus section Cyclobalanopsis) are one of the principal components of forests in the tropical and subtropical climates of East and Southeast Asia. They have experienced relatively recent increases in the diversification rate, driven by changing climates and the Himalayan orogeny. However, the evolutionary history and adaptive mechanisms at the chloroplast genome level in cycle-cup oaks remain largely unknown. Therefore, we studied this problem by conducting chloroplast genomics on 50 of the ca. 90 species. Comparative genomics and other analyses showed that Quercus section Cyclobalanopsis had a highly conserved chloroplast genome structure. Highly divergent regions, such as the ndhF and ycf1 gene regions and the petN-psbM and rpoB-trnC-GCA intergenic spacer regions, provided potential molecular markers for subsequent analysis. The chloroplast phylogenomic tree indicated that Quercus section Cyclobalanopsis was not monophyletic, which mixed with the other two sections of subgenus Cerris. The reconstruction of ancestral aera inferred that Palaeotropics was the most likely ancestral range of Quercus section Cyclobalanopsis, and then dispersed to Sino-Japan and Sino-Himalaya. Positive selection analysis showed that the photosystem genes had the lowest ω values among the seven functional gene groups. And nine protein-coding genes containing sites for positive selection: ndhA, ndhD, ndhF, ndhH, rbcL, rpl32, accD, ycf1, and ycf2. This series of analyses together revealed the phylogeny, evolutionary history, and ecological adaptation mechanism of the chloroplast genome of Quercus section Cyclobalanopsis in the long river of earth history. These chloroplast genome data provide valuable information for deep insights into phylogenetic relationships and intraspecific diversity in Quercus.

Effect of body mass index on 30-day complication rate and implant survival rate after simultaneous bilateral unicompartmental knee arthroplasty: a multicentre retrospective study.

OBJECTIVE: The practice of simultaneous bilateral unicompartmental knee arthroplasty (SBUKA) remains a topic of debate, particularly in patients with obesity. Thus, the purpose of this study was to assess the impact of body mass index (BMI) on the 30-day complication rate and the survival rate of the implant following SBUKA. METHODS: We retrospectively examined the clinical records of 245 patients (490 knees) who underwent SBUKA at the Affiliated Hospital of Qingdao University and the Third Hospital of Hebei Medical University between January 2010 and December 2020. Patients were categorised based on their BMI at the time of surgery into four groups: normal weight (BMI 18.5 to 22.9 kg/m2), overweight (BMI 23.0 to 24.9 kg/m2), obese (BMI 25.0 to 29.9 kg/m2), and severely obese (BMI ≥30 kg/m2). Variables such as length of hospital stay, duration of surgery, and costs of hospitalisation were compared across all groups. Additionally, we recorded the 30-day postoperative complication rate and the time from surgery to any required revision. The Kaplan-Meier survival analysis was employed to evaluate and compare the implant survival rates. RESULTS: The follow-up period for the 245 patients ranged from 39 to 114 months, with an average of 77.05±18.71 months. The incidence of complications within 30 days post-surgery did not significantly differ across the groups (χ2 = 1.102, p = 0.777). The implant survival rates from the lowest to the highest BMI groups were 97.14%, 93.9%, 94.44%, and 96.43%, respectively. Both the rate of implant revision (χ2 =1.612, p = 0.657) and the survival curves of the implants (p = 0.639) showed no statistically significant differences among the groups. CONCLUSIONS: BMI did not influence the 30-day complication rate nor the survival rate of implants following SBUKA, suggesting that SBUKA should not be contraindicated based on BMI alone.

A clinical study based on bidirectional Mendelian randomization: Correlation between generalized anxiety disorder and weight-bearing joints osteoarthritis.

Objectives: Bidirectional Mendelian randomization (MR) combined with clinical case analysis was used to elucidate the relationship between generalized anxiety disorder (GAD) caused by mental overload and the risk of weight-bearing joint (hip/knee) osteoarthritis (OA). Methods: We performed MR analyses using publicly released genome-wide association study summary statistics to measure the causal effects between mental overload and weight-bearing joint OA risk. The primary MR analysis utilized the inverse-variance weighted (IVW) method, complemented by additional methods, including simple mode, weighted mode, MR-Egger regression, and weighted median. The leave-one-out method was used for sensitivity analysis. Concurrently, data from patients with OA (Kellgren-Lawrence grades III-IV) who needed total knee/hip arthroplasty were collected. Patient assessments were conducted utilizing the Western Ontario and McMaster Universities arthritis index, Penn State worry questionnaire, and visual analogue scale. Results: Genetically predisposed GAD did not correlate with the risk of weight-bearing joint OA (IVW odds ratio [OR] = 0.840, 95 % confidence interval = 0.128, 5.50, P = 0.855). In reverse MR analyses, we detected no causal effect of weight-bearing OA on GAD (IVW OR = 1.00, 95 % CI = 0.985, 1.03, P = 0.687). In the clinical case evaluation, weight overload joint OA and GAD were highly correlated. Conclusion: MR analysis indicated no bidirectional causal effect of GAD caused by mental overload on weight-bearing joint (hip or knee) OA. Clinical studies support the finding that GAD is highly correlated with weight-bearing joint OA. However, whether there is a causal relationship between GAD caused by mental overload and weight-overloading joint OA requires further investigation.

Transcriptome sequencing and bioinformatics analysis of gastrocnemius muscle in type 2 diabetes mellitus rats.

OBJECTIVE: Type 2 diabetes mellitus (T2DM) is one of the high risk factors for sarcopenia. However, the pathogenesis of diabetic sarcopenia has not been fully elucidated. This study obtained transcriptome profiles of gastrocnemius muscle in normal and T2DM rats based on high-throughput sequencing technology, which may provide new ideas for exploring the pathogenesis of diabetic sarcopenia. METHODS: Twelve adult male Sprague-Dawley rats were randomly divided into Control group and T2DM group, and gastrocnemius muscle tissue was retained for transcriptome sequencing and real-time quantitative polymerase chain reaction (qRT-PCR) 6 months later. Screening differentially expressed genes (DEGs), Cluster analysis, gene ontology (GO) functional annotation analysis and Kyoto Encyclopedia of Genes and Gnomes (KEGG) functional annotation and enrichment analysis were performed for DEGs. Six DEGs related to apoptosis were selected for qTR-PCR verification. RESULTS: Transcriptomic analysis showed that there were 1016 DEGs between the gastrocnemius muscle of T2DM and normal rats, among which 665 DEGs were up-regulated and 351 DEGs were down-regulated. GO analysis showed that the extracellular matrix organization was the most enriched in biological processes, with 26 DEGs. The extracellular matrix with 35 DEGs was the most abundant cellular component. The extracellular matrix structural constituent, with 26 DEGs, was the most enriched in molecular functions. The highest number of DEGs enriched in biological processes, cellular components and molecular functions were positive regulation of transcription by RNA polymerase II, nucleus and metal ion binding, respectively. There were 78, 230 and 89 DEGs respectively. KEGG pathway enrichment analysis showed that ECM-receptor interaction, PI3K-Akt signaling pathway and TGF-ß signaling pathway(p < 0.001) had higher enrichment degree and number of DEGs. qRT-PCR results showed that the fold change of Map3k14, Atf4, Pik3r1, Il3ra, Gadd45b and Bid were 1.95, 3.25, 2.97, 2.38, 0.43 and 3.6, respectively. The fold change of transcriptome sequencing were 3.45, 2.21, 2.59, 5.39, 0.49 and 2.78, respectively. The transcriptional trends obtained by qRT-PCR were consistent with those obtained by transcriptome sequencing. CONCLUSIONS: Transcriptomic analysis was used to obtain the "gene profiles" of gastrocnemius muscle of T2DM and normal rats. qRT-PCR verification showed that the genes related to apoptosis were differentially expressed. These DEGs and enrichment pathways may provide new ideas for exploring the pathogenesis of diabetic sarcopenia.

Single-cell RNA sequencing reveals different chondrocyte states in femoral cartilage between osteoarthritis and healthy individuals.

Background: Cartilage injury is the main pathological manifestation of osteoarthritis (OA). Healthy chondrocyte is a prerequisite for cartilage regeneration and repair. Differences between healthy and OA chondrocyte types and the role these types play in cartilage regeneration and OA progression are unclear. Method: This study conducted single-cell RNA sequencing (scRNA-seq) on the cartilage from normal distal femur of the knee (NC group) and OA femur (OA group) cartilage, the chondrocyte atlas was constructed, and the differences of cell subtypes between the two groups were compared. Pseudo-time and RNA velocity analysis were both performed to verify the possible differentiation sequence of cell subtypes. GO and KEGG pathway enrichment analysis were used to explore the potential functional characteristics of each cell subtype, and to predict the functional changes during cell differentiation. Differences in transcriptional regulation in subtypes were explored by single-cell regulatory network inference and clustering (SCENIC). The distribution of each cell subtype in cartilage tissue was identified by immunohistochemical staining (IHC). Result: A total of 75,104 cells were included, they were divided into 19 clusters and annotated as 11 chondrocyte subtypes, including two new chondrocyte subtypes: METRNL+ and PRG4+ subtype. METRNL+ is in an early stage during chondrocyte differentiation, and RegC-B is in an intermediate state before chondrocyte dedifferentiation. With cell differentiation, cell subtypes shift from genetic expression to extracellular matrix adhesion and collagen remodeling, and signal pathways shift from HIF-1 to Hippo. The 11 subtypes were finally classified as intrinsic chondrocytes, effector chondrocytes, abnormally differentiated chondrocytes and dedifferentiated chondrocytes. IHC was used to verify the presence and distribution of each chondrocyte subtype. Conclusion: This study screened two new chondrocyte subtypes, and a novel classification of each subtype was proposed. METRNL+ subtype is in an early stage during chondrocyte differentiation, and its transcriptomic characteristics and specific pathways provide a foundation for cartilage regeneration. EC-B, PRG4+ RegC-B, and FC are typical subtypes in the OA group, and the HippO-Taz pathway enriched by these cell subtypes may play a role in cartilage repair and OA progression. RegC-B is in the intermediate state before chondrocyte dedifferentiation, and its transcriptomic characteristics may provide a theoretical basis for intervening chondrocyte dedifferentiation.

Enhancing tendon-bone integration and healing with advanced multi-layer nanofiber-reinforced 3D scaffolds for acellular tendon complexes.

Advancements in tissue engineering are crucial for successfully healing tendon-bone connections, especially in situations like anterior cruciate ligament (ACL) restoration. This study presents a new and innovative three-dimensional scaffold, reinforced with nanofibers, that is specifically intended for acellular tendon complexes. The scaffold consists of a distinct layered arrangement comprising an acellular tendon core, a middle layer of polyurethane/type I collagen (PU/Col I) yarn, and an outside layer of poly (L-lactic acid)/bioactive glass (PLLA/BG) nanofiber membrane. Every layer is designed to fulfill specific yet harmonious purposes. The acellular tendon core is a solid structural base and a favorable environment for tendon cell functions, resulting in considerable tensile strength. The central PU/Col I yarn layer is vital in promoting the tendinogenic differentiation of stem cells derived from tendons and increasing the expression of critical tendinogenic factors. The external PLLA/BG nanofiber membrane fosters the process of bone marrow mesenchymal stem cells differentiating into bone cells and enhances the expression of markers associated with bone formation. Our scaffold's biocompatibility and multi-functional design were confirmed through extensive in vivo evaluations, such as histological staining and biomechanical analyses. These assessments combined showed notable enhancements in ACL repair and healing. This study emphasizes the promise of multi-layered nanofiber scaffolds in orthopedic tissue engineering and also introduces new possibilities for the creation of improved materials for regenerating the tendon-bone interface.

Transcriptomics reveals dynamic changes in the "gene profiles" of rat supraspinatus tendon at three different time points after diabetes induction.

OBJECTIVE: There is increasing evidence that type 2 diabetes mellitus (T2DM) is an independent risk factor for the occur of tendinopathy. Therefore, this study is the first to explore the dynamic changes of the "gene profile" of supraspinatus tendon in rats at different time points after T2DM induction through transcriptomics, providing potential molecular markers for exploring the pathogenesis of diabetic tendinopathy. METHODS: A total of 40 Sprague-Dawley rats were randomly divided into normal (NG, n = 10) and T2DM groups (T2DM, n = 30) and subdivided into three groups according to the duration of diabetes: T2DM-4w, T2DM-8w, and T2DM-12w groups; the duration was calculated from the time point of T2DM rat model establishment. The three comparison groups were set up in this study, T2DM-4w group vs. NG, T2DM-8w group vs. NG, and T2DM-12w group vs. NG. Differentially expressed genes (DEGs) in 3 comparison groups were screened. The intersection of the three comparison groups' DEGs was defined as key genes that changed consistently in the supraspinatus tendon after diabetes induction. Cluster analysis, gene ontology (GO) functional annotation analysis and Kyoto encyclopedia of genes and genomes (KEGG) functional annotation and enrichment analysis were performed for DEGs. RESULTS: T2DM-4w group vs. NG, T2DM-8w group vs. NG, and T2DM-12w group vs. NG detected 519 (251 up-regulated and 268 down-regulated), 459 (342 up-regulated and 117 down-regulated) and 328 (255 up-regulated and 73 down-regulated) DEGs, respectively. 103 key genes of sustained changes in the supraspinatus tendon following induction of diabetes, which are the first identified biomarkers of the supraspinatus tendon as it progresses through the course of diabetes.The GO analysis results showed that the most significant enrichment in biological processes was calcium ion transmembrane import into cytosol (3 DEGs). The most significant enrichment in cellular component was extracellular matrix (9 DEGs). The most significant enrichment in molecular function was glutamate-gated calcium ion channel activity (3 DEGs). The results of KEGG pathway enrichment analysis showed that there were 17 major pathways (p < 0.05) that diabetes affected supratinusculus tendinopathy, including cAMP signaling pathway and Calcium signaling pathway. CONCLUSIONS: Transcriptomics reveals dynamic changes in the"gene profiles"of rat supraspinatus tendon at three different time points after diabetes induction. The 103 DEGs identified in this study may provide potential molecular markers for exploring the pathogenesis of diabetic tendinopathy, and the 17 major pathways enriched in KEGG may provide new ideas for exploring the pathogenesis of diabetic tendinopathy.

The interval between staged bilateral total knee arthroplasties does not affect early complications of the second knee or long-term function of the first and second knees.

BACKGROUND: This study explored the optimal time interval between staged bilateral total knee arthroplasty (BTKA) to minimize early complications of the second TKA and maximise the long-term function of the first and second knees. METHODS: We retrospectively reviewed 266 patients who underwent staged BTKA between 2013 and 2018. Groups 1-4 had time intervals between BTKAs of 1-6, 6-12, 12-18, and 18-24 months, respectively. Demographics, postoperative complications within 90 days of the second TKA, Knee Society Score (KSS), and Western Ontario and McMaster Universities Arthritis Index (WOMAC) score were compared among the groups. RESULTS: In total, 54, 96, 75, and 41 patients were assigned to groups 1-4, respectively. Although group 1 had the highest overall complication rate (11.11%), there was no significant difference in the complication rate among the four groups. Also, no significant differences were found among the four groups in functional and patient-reported outcomes, in either the first or second knee at 5 years postoperatively, including KSS-knee, KSS-function, WOMAC-pain, WOMAC-stiffness, and WOMAC-physical function. The interval between BTKA did not influence complications or the function of the second knee. The TKA type (posterior-stabilised vs. medial-pivot) and age did not correlate significantly with any scores. CONCLUSIONS: There was no group difference in early complications of the second TKA, and postoperative function was equivalent between the two knees and did not vary by the interval between surgeries. The results of this study give surgeons and patients more choices. If patients cannot tolerate severe symptoms in the contralateral knee after the first TKA, the second TKA should be performed as early as possible. If knee joint function is not well recovered after the first TKA, and patients are anxious to undergo the second TKA, surgeons can advise patients to postpone the operation based on these results.

Different reference genomes determine different results: Comparing SNP calling in RAD-seq of Engelhardia roxburghiana using different reference genomes.

Advances in next-generation sequencing (NGS) have significantly reduced the cost and improved the efficiency of obtaining single nucleotide polymorphism (SNP) markers, particularly through restriction site-associated DNA sequencing (RAD-seq). Meanwhile, the progression in whole genome sequencing has led to the utilization of an increasing number of reference genomes in SNP calling processes. This study utilized RAD-seq data from 242 individuals of Engelhardia roxburghiana, a tropical tree of the walnut family (Juglandaceae), with SNP calling conducted using the STACKS pipeline. We aimed to compare both reference-based approaches, namely, employing a closely related species as the reference genome versus the species itself as the reference genome, to evaluate their respective merits and limitations. Our findings indicate a substantial discrepancy in the number of obtained SNPs between using a closely related species as opposed to the species itself as reference genomes, the former yielded approximately an order of magnitude fewer SNPs compared to the latter. While the missing rate of individuals and sites of the final SNPs obtained in the two scenarios showed no significant difference. The results showed that using the reference genome of the species itself tends to be prioritized in RAD-seq studies. However, if this is unavailable, considering closely related genomes is feasible due to their wide applicability and low missing rate as alternatives. This study contributes to enrich the understanding of the impact of SNP acquisition when utilizing different reference genomes.

Causal relationship between serum metabolites and juvenile idiopathic arthritis: a mendelian randomization study.

BACKGROUND: Juvenile Idiopathic Arthritis (JIA) is a condition that occurs when individuals under the age of 16 develop arthritis that lasts for more than six weeks, and the cause is unknown. The development of JIA may be linked to serum metabolites. Nevertheless, the association between JIA pathogenesis and serum metabolites is unclear, and there are discrepancies in the findings across studies. METHODS: In this research, the association between JIA in humans and 486 serum metabolites was assessed using genetic variation data and genome-wide association study. The identification of causal relationships was accomplished through the application of univariate Mendelian randomization (MR) analysis. Various statistical methods, including inverse variance weighted and MR-Egger, were applied to achieve this objective. To ensure that the findings from the MR analysis were trustworthy, a number of assessments were carried out. To ensure the accuracy of the obtained results, a range of techniques were utilised including the Cochran Q test, examination of the MR-Egger intercept, implementation of the leave-one-out strategy, and regression analysis of linkage disequilibrium scores. In order to identify the specific metabolic pathways associated with JIA, our primary objective was to perform pathway enrichment analysis using the Kyoto Encyclopedia of Genes and Genomes. RESULTS: Two-sample summary data MR analyses and sensitivity analyses showed that five metabolites were significantly causally associated with JIA, including two risk factors-kynurenine (odds ratio [OR]: 16.39, 95% confidence interval [CI]: 2.07-129.63, p = 5.11 × 10- 6) and linolenate (OR: 16.48, 95% CI: 1.32-206.22, p = 0.030)-and three protective factors-3-dehydrocarnitine (OR: 0.32, 95% CI: 0.14-0.72, p = 0.007), levulinate (4-oxovalerate) (OR: 0.40, 95% CI: 0.20-0.80, p = 0.010), and X-14,208 (phenylalanylserine) (OR: 0.68, 95% CI: 0.51-0.92, p = 0.010). Furthermore, seven metabolic pathways, including α-linolenic acid metabolism and pantothenate and CoA biosynthesis, are potentially associated with the onset and progression of JIA. CONCLUSION: Five serum metabolites, including kynurenine and 3-dehydrocarnitine, may be causally associated with JIA. These results provide a theoretical framework for developing effective JIA prevention and screening strategies.

Comparison of different degrees of varus deformity correction with open-wedge high tibial osteotomy: a retrospective study over 5 years.

OBJECTIVE: This study aims to investigate the clinical efficacy and complications associated with open-wedge high tibial osteotomy (OWHTO) in the treatment of medial compartment knee osteoarthritis. Additionally, the compensatory changes in the hip, patellofemoral, and ankle regions will be assessed through imaging. METHODS: A retrospective analysis of clinical data pertaining to 86 patients who underwent OWHTO at the Affiliated Hospital of Qingdao University from January 2015 to September 2018 was conducted. The weight-bearing line ratio (WBLR) was measured postoperatively, and patients were categorized into a normal group (50% < WBLR ≤ 62.5%, n = 67) and an overcorrection group (WBLR > 62.5%, n = 19). Various parameters, including hip-knee-ankle angle (HKA), medial proximal tibial angle (MPTA), lateral distal femoral angle (LDFA), joint line convergence angle (JLCA), and posterior tibial slope (PTS), were measured before surgery and at the last follow-up to assess lower limb line correction. The compensatory changes in adjacent joints were evaluated by measuring hip abductor angle (HAA), tibial plafond inclination (TPI), talus inclination angle (TIA), Carton-Deschamps index, lateral patellar tilt (LPT), lateral patellar shift (LPS), medial patellofemoral space, and lateral patellofemoral space in both groups. The American Hospital for Special Surgery (HSS) score and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) of the affected knee were assessed before surgery and at the last follow-up, and the incidence of complications in both groups was analyzed. RESULTS: Postoperative complications occurred in 26.32% (five cases) of the overcorrection group and 5.97% (four cases) of the normal group, with a statistically significant difference (χ2 = 4.548, p = 0.033). No significant differences were observed in HSS and WOMAC between the two groups at the last follow-up. HAA was - 2.44 ± 1.98° in the overcorrection group and - 1.16 ± 2.1° in the normal group, with a statistically significant difference (t = 2.32, p = 0.023). There were no significant differences in other imaging indexes. CONCLUSION: Overcorrection of varus deformity may not significantly impact clinical outcomes within 5 years post-OWHTO but may elevate the incidence of postoperative complications and lead to increased compensatory adduction of the hip.

Single-cell RNA sequencing reveals the impact of mechanical loading on knee tibial cartilage in osteoarthritis.

Articular cartilage degeneration is one of the major pathogenic alterations observed in knee osteoarthritis (KOA). Mechanical stress has been verified to contribute to KOA development. To gain insight into the pathogenic mechanism of KOA development, we investigated chondrocyte subsets under different mechanical loading conditions via single-cell RNA sequencing (scRNA-seq). Articular cartilage tissues from both high mechanical loading (named the OATL group) and low mechanical loading (named the OATN group) surfaces were obtained from the proximal tibia of KOA patients, and scRNA-seq was conducted. Chondrocyte subtypes, including a new subset, HTC-C (hypertrophic chondrocytes-C), and their functions, development and interactions among cell subsets were identified. Immunohistochemical staining was also conducted to verify the existence and location of each chondrocyte subset. Furthermore, differentially expressed genes (DEGs) and their functions between regions with high and low mechanical loading were identified. Based on Gene Ontology terms for the DEGs in each cell type, the characteristic of cartilage degeneration in the OATL region was clarified. Mitochondrial dysfunction may be involved in the KOA process in the OATN region.

Model Properties and Clinical Application in the Finite Element Analysis of Knee Joint: A Review.

The knee is the most complex joint in the human body, including bony structures like the femur, tibia, fibula, and patella, and soft tissues like menisci, ligaments, muscles, and tendons. Complex anatomical structures of the knee joint make it difficult to conduct precise biomechanical research and explore the mechanism of movement and injury. The finite element model (FEM), as an important engineering analysis technique, has been widely used in many fields of bioengineering research. The FEM has advantages in the biomechanical analysis of objects with complex structures. Researchers can use this technology to construct a human knee joint model and perform biomechanical analysis on it. At the same time, finite element analysis can effectively evaluate variables such as stress, strain, displacement, and rotation, helping to predict injury mechanisms and optimize surgical techniques, which make up for the shortcomings of traditional biomechanics experimental research. However, few papers introduce what material properties should be selected for each anatomic structure of knee FEM to meet different research purposes. Based on previous finite element studies of the knee joint, this paper summarizes various modeling strategies and applications, serving as a reference for constructing knee joint models and research design.

Identification of CD8+ T cell-related biomarkers and immune infiltration characteristic of rheumatoid arthritis.

Rheumatoid arthritis (RA) is an autoimmune rheumatic disease, which do not respond well to current treatment partially. Therefore, further in-depth elucidation of the molecular mechanism and pathogenesis of RA is urgently needed for the diagnosis, personalized therapy and drug development. Herein, we collected 111 RA samples from Gene Expression Omnibus (GEO) database, and conducted differentially expressed genes and GESA analysis. Abnormal activation and imbalance of immune cells in RA were observed. WGCNA was utilized to explore the gene modules and CD8+ T cell-related genes (CRGs) were chosen for KEGG and GO analysis. Besides, to explore biomarkers of RA in depth, machine learning algorithms and bioinformatics analysis were used, and we identified GDF15, IGLC1, and IGHM as diagnostic markers of RA, which was confirmed by clinical samples. Next, ssGSEA algorithms were adopted to investigate the differences in immune infiltration of 23 immune cell subsets between RA and healthy control group. Finally, optimal classification analysis based on consensus clustering combined with ssGSEA algorithms were conducted. GDF15 was revealed that to be positively correlated with mast cells and type 2 T helper cells, but negatively correlated with most other immune cells. On the other hand, IGHM and IGLC1 were negatively correlated with CD56dim natural killer cells, while positively associated with other immune cells. Finally, RA samples in subtype A exhibited a higher immune infiltration status. This study could provide guidance for individualized treatment of RA patients and provide new targets for drug design.

Untargeted metabolomics reveals dynamic changes in metabolic profiles of rat supraspinatus tendon at three different time points after diabetes induction.

Objective: To investigate the dynamic changes of metabolite composition in rat supraspinatus tendons at different stages of diabetes by untargeted metabolomics analysis. Methods: A total of 80 Sprague-Dawley rats were randomly divided into normal (NG, n = 20) and type 2 diabetes mellitus groups (T2DM, n = 60) and subdivided into three groups according to the duration of diabetes: T2DM-4w, T2DM-12w, and T2DM-24w groups; the duration was calculated from the time point of T2DM rat model establishment. The three comparison groups were set up in this study, T2DM-4w group vs. NG, T2DM-12w group vs. T2DM-4w group, and T2DM-24w group vs. T2DM-12w group. The metabolite profiles of supraspinatus tendon were obtained using tandem mass spectrometry. Metabolomics multivariate statistics were used for metabolic data analysis and differential metabolite (DEM) determination. The intersection of the three comparison groups' DEMs was defined as key metabolites that changed consistently in the supraspinatus tendon after diabetes induction; then, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis was performed. Results: T2DM-4w group vs. NG, T2DM-12w group vs. T2DM-4w group, and T2DM-24w group vs. T2DM-12w group detected 94 (86 up-regulated and 8 down-regulated), 36 (13 up-regulated and 23 down-regulated) and 86 (24 up-regulated and 62 down-regulated) DEMs, respectively. Seven key metabolites of sustained changes in the supraspinatus tendon following induction of diabetes include D-Lactic acid, xanthine, O-acetyl-L-carnitine, isoleucylproline, propoxycarbazone, uric acid, and cytidine, which are the first identified biomarkers of the supraspinatus tendon as it progresses through the course of diabetes. The results of KEGG pathway enrichment analysis showed that the main pathway of supraspinatus metabolism affected by diabetes (p < 0.05) was purine metabolism. The results of the KEGG metabolic pathway vs. DEMs correlation network graph revealed that uric acid and xanthine play a role in more metabolic pathways. Conclusion: Untargeted metabolomics revealed the dynamic changes of metabolite composition in rat supraspinatus tendons at different stages of diabetes, and the newly discovered seven metabolites, especially uric acid and xanthine, may provide novel research to elucidate the mechanism of diabetes-induced tendinopathy.

Single-cell RNA sequencing reveals differences between force application and bearing in ankle cartilage.

Chondrocytes are the major functional elements of articular cartilage. Force has been demonstrated to influence the structure and function of articular cartilage and chondrocytes. Therefore, it is necessary to evaluate chondrocytes under different force conditions to gain deep insight into chondrocyte function. Six cartilage tissues from the distal tibia (referred to as the AT group) and five cartilage tissues from the trochlear surface of the talus (referred to as the ATa group) were obtained from 6 donors who had experienced fatal accidents. Single-cell RNA sequencing was used on these samples. A total of 149,816 cells were analyzed. Nine chondrocyte subsets were ultimately identified. Pseudotime analyses, enrichment analyses, cell-cell interaction studies, and single-cell regulatory network inference and clustering were performed for each cell type, and the differences between the AT and ATa groups were analyzed. Immunohistochemical staining was used to verify the existence of each chondrocyte subset and its distribution. The results suggested that reactive oxygen species related processes were active in the force-applied region, while tissue repair processes were common in the force-bearing region. Although the number of prehypertrophic chondrocytes was small, these chondrocytes seemed to play an important role in the ankle.

Single-cell RNA sequencing reveals distinct chondrocyte states in femoral cartilage under weight-bearing load in Rheumatoid arthritis.

Introduction: Rheumatoid arthritis (RA) is a common autoimmune joint disease, the pathogenesis of which is still unclear. Cartilage damage is one of the main manifestations of the disease. Chondrocytes are the main functional component of articular cartilage, which is relevant to disease progression. Mechanical loading affects the structure and function of articular cartilage and chondrocytes, but the effect of weight bearing on chondrocytes in rheumatoid arthritis is still unclear. Methods: In this paper, single-cell RNA sequencing (scRNA-seq) was performed on collected cartilage from the weight-bearing region (Fb group) and non-weight-bearing region (Fnb group) of the femur, and the differences between the Fb and Fnb groups were analyzed by cell type annotation, pseudotime analysis, enrichment analysis, cell interactions, single-cell regulatory network inference and clustering (SCENIC) for each cell type. Results: A total of 87,542 cells were analyzed and divided into 9 clusters. Six chondrocyte subpopulations were finally identified by cellular annotation, and two new chondrocyte subtypes were annotated as immune-associated chondrocytes. The presence of each chondrocyte subpopulation and its distribution were verified using immunohistochemical staining (IHC). In this study, the atlas of femoral cartilage in knee rheumatoid arthritis and 2 new immune-related chondrocytes were validated using scRNA-seq and IHC, and chondrocytes in the weight-bearing and non-weight-bearing regions of the femur were compared. There might be a process of macrophage polarization transition in MCs in response to mechanical loading, as in macrophages. Conclusion: Two new immune-associated chondrocytes were identified. MCs have contrasting functions in different regions, which might provide insight into the role of immune and mechanical loading on chondrocytes in the development of knee rheumatoid osteoarthritis.