METTL3-mediated long non-coding RNA MIR99AHG methylation targets miR-4660 to promote bone marrow mesenchymal stem cell osteogenic differentiation.

Whether long non-coding RNA Mir-99a-Let-7c Cluster Host Gene (LncRNA MIR99AHG) is involved in osteoporosis (OP) remains vague, so we hereby center on its implication. Old C57BL/6J mice were injected with the silencing lentivirus of MIR99AHG and subjected to microCT analysis and immunohistochemistry on osteogenic cells. The osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) with or without transfection was determined by alkaline phosphatase (ALP) and Alizarin Red S staining. Total N(6)-methyladenosine (m6A) on the bone marrow mesenchymal stem cells (BMSCs) was quantified. The potential methylation site and the complementary binding sites with candidate microRNA (miR) were predicted via bioinformatic analyses, with the latter being confirmed via dual-luciferase reporter, RNA immunoprecipitation and RNA pull-down assays. Quantitative real-time PCR and Western blot were used for quantification assays. MIR99AHG was decreased during the osteogenic differentiation of BMSCs, where increased Osterix (OSX), Collagen, Type I, Alpha 1 (Col1A1), Osteocalcin (OCN) and RUNX Family Transcription Factor 2 (RUNX2) as well as more color-stained areas were found. Also, silencing MIR99AHG relieved the OP in mice and reduced the loss of osteogenic cells. M6A methylation in undifferentiated BMSCs was low and MIR99AHG overexpression abolished the effects of overexpressed METTL3 on promoting osteogenic differentiation. MiR-4660, which was downregulated in BMSCs without differentiation but increased during osteogenic differentiation, could bind with MIR99AHG. Furthermore, miR-4660 promoted osteogenic differentiation and reversed the effects of overexpressed MIR99AHG. The present study demonstrated that METTL3-mediated LncRNA MIR99AHG methylation enhanced the osteogenic differentiation of BMSCs via targeting miR-4660.

Objective Evaluation of Neurogenic Intermittent Claudication for Patients With Lumbar Spinal Stenosis Based on Plantar Pressure Analysis.

STUDY DESIGN: A cross-sectional study. OBJECTIVE: To quantify the severity of neurogenic intermittent claudication (NIC) for patients with lumbar spinal stenosis (LSS) based on the center of pressure trajectory. SUMMARY OF BACKGROUND DATA: NIC is one of the typical symptoms of LSS. So far, the severity level of NIC is mainly evaluated by the subjective description of patients, which might be biased by patients' background differences and thus lead to an ineffective diagnosis or inappropriate treatment for LSS. Therefore, it remains necessary to develop a reliable clinical technique for quantitative evaluation of NIC to achieve more effective therapy for LSS. MATERIALS AND METHODS: In the present study, the Footscan pressure system was used to detect the center of pressure trajectory. The real-time walking distance (rtWD) and the corresponding displacement of the medial-lateral center of pressure (ML-COP) were calculated based on the trajectory. The differences of ML-COP between LSS and control groups were analyzed using a one-way repeated measures analysis of variance. Regression and Pearson correlation analysis were used to investigate the correlation between rtWD and ML-COP, as well as the relation between the Oxford Claudication Score (OCS) and clinical evaluation indicators. RESULTS: The present study included 31 LSS patients and 31 healthy controls. There were no significant differences in demographic data between the two groups ( P >0.05). The results indicated that ML-COP would increase with the number of laps in the LSS group while not in the control group. Also, a linear relationship was identified between the ML-COP and rtWD for LSS patients ( R2 >0.80, P <0.05). Since the incremental rate of ML-COP for LSS patients was reflected by the regression coefficients of the linear regression analysis, thus the regression coefficients were defined as the claudication correlation coefficients (CCCs). In addition, it was indicated by the statistical analysis that there was a strong positive correlation between OCS and CCC ( r =0.96; P <0.001) and a medium negative correlation with final walking distance ( r =-0.67; P <0.001). It was also noticed that there was no significant correlation between the average ML-COP and OCS ( r =-0.03; P =0.864). CONCLUSIONS: The ML-COP of LSS patients would increase with the patients' walking distance. This incremental rate, characterized by the CCC, would be used as an effective indicator to quantify the severity level of the NIC for potentially more accurate and reliable diagnosis, evaluation, and treatment of LSS. LEVEL OF EVIDENCE: 3.

An overview of hydrogel-based intra-articular drug delivery for the treatment of osteoarthritis.

Drug administration by intra-articular injection is an emerging popular treatment for knee osteoarthritis (OA). This method of drug administration minimizes the toxic effects of the drugs administered systemically, and maximizes local effects. However, traditional oral drugs delivered via intra-articular injection are limited by the lack of sustained release. Injectable materials such as hydrogels or hydrogel microspheres have been extensively studied for their applications as intra-articular injection for the treatment of OA, which is attribute to their minimally invasive manner, extended drug retention time and high loading efficiency. In this review, we summarized hydrogel types and hydrogel characteristics for intra-articular injection, and the drugs, proteins and cells used in the injectable delivery systems. Through this review, we hope to inspire researchers to construct novel hydrogel-based delivery system for the intra-articular injection treatment of knee OA.

Gene signatures in osteoarthritic acetabular labrum using microarray analysis.

BACKGROUND: Osteoarthritis (OA) is the most common chronic joint disease. This study aimed to uncover underlying mechanisms of OA pathogenesis and explore the potential biomarkers of osteoarthritic acetabular labrum. METHODS: The microarray data GSE60762 was utilized, containing five OA acetabular labrum samples and three healthy control samples. Data were preprocessed by oligo package and the differentially expressed genes (DEGs) were identified using limma package with predefined criteria, followed by functional enrichment analysis by the GoFunction in R Bioconductor, and protein-protein interaction (PPI) network analysis. RESULTS: As a result, 141 DEGs (44 were up-regulated and 97 were down-regulated) were identified between OA and healthy acetabular labrum cells. Up-regulated genes including CDH2 and WNT5A were significantly enriched in intracellular signal transduction function, while down-regulated genes such as KDR, FLT1 and CDH5 were remarkably correlated with cardiovascular system development. FLT1, KDR, CDH2 and CDH5 were the striking nodes in the PPI network. CONCLUSION: CDH2, WNT5A, KDR, FLT1 and CDH5 might serve as the biomarkers of OA prognosis. Intracellular signal transduction and cardiovascular system development might play significant roles in the destruction of labrum during OA progression. However, more experimental validations are warranted to confirm our findings.

Tumor necrosis factor-like weak inducer of apoptosis regulates particle-induced inflammatory osteolysis via the p38 mitogen-activated protein kinase signaling pathway.

Periprosthetic osteolysis is the predominant cause of artificial joint loosening. Previous studies have demonstrated that p38 mitogen-activated protein kinase (p38 MAPK) may be involved in periprosthetic osteolysis. Tumor necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK) is a member of the TNF family and is a multifunctional cytokine, which regulates cellular proliferation, angiogenesis, inflammation and apoptosis via the p38 MAPK signaling pathway. The present study investigated the expression levels of TWEAK and p38 MAPK in periprosthetic interface membranes and in RAW264.7 monocyte/macrophage cells, which were treated with titanium (Ti) particle stimulation, with or without a p38 inhibitor (SB203580). This was performed to determine whether TWEAK was involved in the particle-induced inflammatory osteolysis via the p38 MAPK signaling pathway. The expression levels of TWEAK, p38 MAPK and phosphorylated (p-)p38 MAPK were evaluated in the periprosthetic interface membrane tissues and the RAW cells by reverse transcription-quantitative polymerase chain reaction and western blotting. The contents of interleukin-6 and monocyte chemoattractant protein-1 in the supernatant were measured by ELISA. The results demonstrated that the expression levels of TWEAK and p-p38 MAPK increased in the periprosthetic interface membrane tissues and the RAW cells stimulated with Ti particles, suggesting that TWEAK was involved in particle-induced inflammatory osteolysis via the p38 MAPK signaling pathway.

Secondary definitive surgery for multiple injuries from Wenchuan earthquake in China.

OBJECTIVE: To investigate the opportune time of secondary definitive surgery for patients with multiple injuries from earthquakes based on the acute physiology and chronic health evaluation II (APACHE II) score and the principles of damage control. METHODS: Twenty-one patients with critical earthquake injuries were treated with damage control strategies, followed by medical support and surgical intervention to restore their physical potential in the intensive care unit (ICU). Successive APACHE II scoring was adopted to evaluate the patients'physiological status, and then, internal fixation of fractures and other definitive operations were performed. RESULTS: All the patients were effectively treated with few complications, low deformity rate and no death. CONCLUSIONS: Appropriate evaluation of patients?physiological potential, right decision on surgical time and proper operative method can reduce the rates of complications, disability and death for patients with critical earthquake injuries.

[Definitive postponed surgery for the casualties with multiple injuries in the earthquake].

OBJECTIVE: To explore the treatment of casualties who suffered from multiple injuries in earthquake and had been treated by damage control (DC) immediately,and the definite postponed surgery time by way of APACHE II score. METHODS: From May to June 2008, 21 casualties who had undergone DC accepted further treatment of medicine and surgery, and recovered physical potentiality in the intensive care unit (ICU). APACHE II score was adopted to evaluate the casualties' physical potentiality. Then, internal fixation of intra-articular fractures and centrum fractures, alternation from external fixation to internal fixation, reconstruction of soft tissue was applied by stages according to the plan. RESULTS: All the patients were effectively cured after definite postponed surgery. There was less complication, low deformity ratio and no death happened. CONCLUSION: Timely evaluation of the casualties' physical potentiality, appropriate surgery time and exact surgery can reduce the casualties' complication, deformity rate and death rate.