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.

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.

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.

Adaptive divergence and genetic vulnerability of relict species under climate change: a case study of Pterocarya macroptera.

BACKGROUND AND AIMS: Understanding adaptive genetic variation and whether it can keep pace with predicted future climate change is critical in assessing the genetic vulnerability of species and developing conservation management strategies. The lack of information on adaptive genetic variation in relict species carrying abundant genetic resources hinders the assessment of genetic vulnerability. Using a landscape genomics approach, this study aimed to determine how adaptive genetic variation shapes population divergence and to predict the adaptive potential of Pterocarya macroptera (a vulnerable relict species in China) under future climate scenarios. METHODS: We applied restriction site-associated DNA sequencing (RAD-seq) to obtain 8244 single-nucleotide polymorphisms (SNPs) from 160 individuals across 28 populations. We examined the pattern of genetic diversity and divergence, and then identified outliers by genetic differentiation (FST) and genotype-environment association (GEA) methods. We further dissected the effect of geographical/environmental gradients on genetic variation. Finally, we predicted genetic vulnerability and adaptive risk under future climate scenarios. KEY RESULTS: We identified three genetic lineages within P. macroptera: the Qinling-Daba-Tianmu Mountains (QDT), Western Sichuan (WS) and Northwest Yunnan (NWY) lineages, which showed significant signals of isolation by distance (IBD) and isolation by environment (IBE). IBD and IBE explained 3.7-5.7 and 8.6-12.8 % of the genetic structure, respectively. The identified GEA SNP-related genes were involved in chemical defence and gene regulation and may exhibit higher genetic variation to adapt to the environment. Gradient forest analysis revealed that the genetic variation was mainly shaped by temperature-related variables, indicating its adaptation to local thermal environments. A limited adaptive potential was suggested by the high levels of genetic vulnerability in marginal populations. CONCLUSIONS: Environmental gradient mainly shaped the population differentiation of P. macroptera. Marginal populations may be at high risk of extinction, and thus proactive management measures, such as assisted gene flow, are required to ensure the survival of these populations.

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.

Recent advance in phytonanomedicine and mineral nanomedicine delivery system of the treatment for acute myeloid leukemia.

Acute myeloid leukemia (AML) is an invasive hematopoietic malignancy caused by excessive proliferation of myeloblasts. Classical chemotherapies and cell transplantation therapies have remarkable efficacy in AML treatment; however, 30-40% of patients relapsed or had refractory disease. The resistance of AML is closely related to its inherent cytogenetics or various gene mutations. Recently, phytonanomedicine are found to be effective against resistant AML cells and have become a research focus for nanotechnology development to improve their properties, such as increasing solubility, improving absorption, enhancing bioavailability, and maintaining sustained release and targeting. These novel phytonanomedicine and mineral nanomedicine, including nanocrystals, nanoemulsion, nanoparticles, nanoliposome, and nanomicelles, offer many advantages, such as flexible dosages or forms, multiple routes of administration, and curative effects. Therefore, we reviewed the application and progress of phytomedicine in AML treatment and discussed the limitations and future prospects. This review may provide a solid reference to guide future research on AML treatment.

Proximal tibia osteotomy with absorbable spacer combined with fibular osteotomy versus high tibial osteotomy for medial compartmental knee osteoarthritis.

PURPOSE: The study aimed to compare the perioperative complications, short-term clinical outcomes, patient-reported outcomes, and radiographic parameters of tibiofibular proximal osteotomy combined with absorbable spacer insertion (TPOASI) and open-wedge high tibial osteotomy (OWHTO) in a two year postoperative time period. METHODS: A total of 160 patients with Kellgren-Lawrence classification grade 3 medial compartmental knee OA were randomized to receive either TPOASI (n = 82) or OWHTO (n = 78). The primary and secondary outcomes were measured preoperatively, postoperatively, and at each follow-up examination. The primary outcomes were the between-group change in the Western Ontario and McMaster Universities Global score (WOMAC). Secondary measures included visual analog scale (VAS), radiographic parameters, American Knee Society Score (KSS), operation time, blood loss, length of incision, hospital stay, and relevant complications. Postoperative radiographic parameters, including the femorotibial angle (FTA), varus angle (VA), and joint line convergence angle (JLCA), were measured to evaluate the correction of varus deformity. RESULTS: No significant differences were found in the baseline data between the two groups. Both methods improved functional status and pain postoperatively. For primary outcomes of both groups, statistical difference was observed in WOMAC scores at the 6-month follow-up (P < 0.001). For secondary outcomes, no statistical difference was observed between the groups during the 2-year follow-up (P > 0.05). For TPOASI vs. OWHTO, the mean hospital stay (6.6 ± 1.3 days vs. 7.8 ± 2.1 days) was shorter (P < 0.001), and both blood loss (70.56 ± 35.58 vs. 174.00 ± 66.33 mL) and complication rate (3.7% vs. 12.8%) were significantly lower (P < 0.005 for both). CONCLUSIONS: Both approaches showed satisfactory functional outcomes and alleviated pain. However, TPOASI is a simple, feasible method with few complications, and it could be widely used.

Elevated lymphotoxin-α (TNFß) is associated with intervertebral disc degeneration.

BACKGROUND: Intervertebral disc degeneration (IVDD) is a primary cause of degenerative disc diseases; however, the mechanisms underlying the degeneration remain unclear. The immunoinflammatory response plays an important role in IVDD progression. The inflammatory cytokine lymphotoxin-α (LTα), formerly known as TNFß, is associated with various pathological conditions, while its role in the pathogenesis of IVDD remains elusive. METHODS: Real-time quantitative polymerase chain reaction (RT-qPCR), Western blotting (WB), and enzyme-linked immunosorbent assays were used to assess the levels of LTα in human nucleus pulposus (NP) tissues between degeneration and control groups. The plasma concentrations of LTα and C-reactive protein (CRP) were compared between healthy and IVDD patients. Rat primary NP cells were cultured and identified via immunofluorescence. Methyl-thiazolyl-tetrazolium assays and flow cytometry were used to evaluate the effects of LTα on rat NP cell viability. After NP cells were treated with LTα, degeneration-related molecules (Caspase-3, Caspase-1, matrix metalloproteinase (MMP) -3, aggrecan and type II collagen) were measured via RT-qPCR and WB. RESULTS: The levels of both the mRNA and protein of LTα in human degenerated NP tissue significantly increased. Plasma LTα and CRP did not differ between healthy controls and IVDD patients. Rat primary NP cells were cultured, and the purity of primary NP cells was > 90%. Cell experiments showed inversely proportional relationships among the LTα dose, treatment time, and cell viability. The optimal conditions (dose and time) for LTα treatment to induce rat NP cell degeneration were 5 µg/ml and 48 ~ 72 h. The apoptosis rate and the levels of Caspase-3, Caspase-1, and MMP-3 significantly increased after LTα treatment, while the levels of type II collagen and aggrecan were decreased, and the protein expression levels were consistent with their mRNA expression levels. CONCLUSIONS: This study demonstrated that elevated LTα is closely associated with IVDD and that LTα may induce NP cell apoptosis and reduce important extracellular matrix (ECM) proteins, which cause adverse effects on IVDD progress. Moreover, the optimal conditions for LTα treatment to induce NP cell degeneration were determined.

Tanshinone IIA regulates human AML cell proliferation, cell cycle, and apoptosis through miR-497-5p/AKT3 axis.

BACKGROUND: The roots of Salvia miltiorrhiza are used in traditional Chinese medicine (TCM) and have high medicinal value. Tanshinone IIA (Tan IIA) is the active ingredient of Salvia miltiorrhiza which can inhibit the growth of acute leukemia cell lines in vitro, although the mechanism remains unclear. METHODS: CCK-8 assays and BrdU stain were used to evaluate cell proliferation ability. Western blot analysis was used to detect protein expression. miR-497-5p expression level was detected by using qRT-PCR, and Annexin V-FITC/propidium iodide (PI) was used to detect cell apoptosis. RESULTS: Here we reported that Tan IIA could inhibit cell proliferation, induce cell cycle arrest, and promote cell apoptosis in acute myeloid leukemia (AML) cells. Thus, Tan IIA had the anti-cancer activity in AML cell lines, which was likely mediated by up-regulation of miR-497-5p expression. Our data further showed that in AML cells, the same effects were observed with overexpression of miR-497-5p by a miR-497-5p mimic. We demonstrated that Tan IIA could inhibit the expression of AKT3 by up-regulating the expression of miR-497-5p. We subsequently identified that AKT3 was the direct target of miR-497-5p, and that treatment with Tan IIA obviously reversed the effect of treatment with an miR-497-5p inhibitor under harsh conditions. In turn, PCNA expression was increased and cleaved Caspase-3 was suppressed, which contributed to the growth of AML cells. CONCLUSIONS: Our results showed that Tan IIA could inhibit cell proliferation in AML cells through miR-497-5p-mediated AKT3 downregulation pathway.

Proximal fibular osteotomy alleviates medial compartment knee osteoarthritis in a mouse model.

PURPOSE: The purpose of this study was to establish a mouse model of proximal fibular osteotomy (PFO), and to determine if PFO could delay degeneration of the medial compartment of the knee joint in a mouse model. METHODS: An animal model of destabilization of the medial meniscus (DMM) was used to induce post-traumatic knee osteoarthritis (OA). PFO was performed to examine the effectiveness of PFO on protection against medial compartment knee OA. Micro-CT was used to observe osteosclerosis development in the subchondral bone, and Safranin O-fast green staining was used to evaluate the progression of articular cartilage destruction. The condylar-plateau angle (CPA) and anatomical femorotibial angle (aFTA) were measured to determine whether knee alignment was changed after PFO. RESULTS: PFO treatment could decrease osteophyte formation and osteosclerosis development in the subchondral bone, as observed by micro-CT. The value of the ratio of trabecular bone volume to total volume (BV/TV) of DMM+PFO group was lower than that of DMM group. PFO also inhibited the progression of articular cartilage destruction. DMM + PFO group displayed decreased maximal and summed OA scores, as compared with DMM group. Moreover, the change of knee alignment was reduced by PFO, which might be the mechanism of PFO alleviating medial compartment knee OA. CONCLUSION: Our results indicated that PFO could alleviate medial compartment knee OA in a mouse model.

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.

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 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.

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.

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.

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.

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.

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.

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.

Effects of reaction environments on the structure and physicochemical properties of chitosan and its derivatives.

The structural transformation of chitosan caused by reaction environment is one of the main factors affecting its functional properties. Herein, the effects of homogeneous and heterogeneous reactions on the structure and properties of chitosan were investigated. The pretreatment of reaction increased the deacetylation degree (DD) of chitosan and resulted in its degradation. In contrast, the effect of alkali dissolution process on the above characteristics was less than 8 %. In addition, the modification of functional groups and alkaline reaction environment leaded to further degradation and deacetylation of chitosan. The alkali swelling increased the specific surface area of chitosan particles, but not completely destroy its internal structure to ensure the uniformity of reaction. Interestingly, the homogeneous modification of dissolved chitosan at lower temperature reduced the degree of substitution (DS) of its derivatives but made them exhibit self-assembly properties. This study provided theoretical basis for precise preparation and application of chitosan derivatives.