No association between telomere length and osteonecrosis of the femoral head

Causal relationship between telomere length and osteonecrosis: Bidirectional two-sample Mendelian randomization analysis

Recent mounting evidence suggests that shortening of telomere length (TL) is associated with impaired bone health; yet, a genetic causal relationship between TL and osteonecrosis remains uncertain. This study aimed to investigate the potential causal relationship between TL and osteonecrosis using bidirectional two-sample Mendelian randomization (MR). Genome-wide association study summary statistics for TL were sourced from the IEU Open genome-wide association study project, while osteonecrosis data were obtained from the FinnGen Biobank database. A range of MR methodologies-including inverse variance weighting, MR-Egger, weighted median, simple mode, and weighted mode-were utilized for analysis, along with the MR-Egger intercept method for horizontal pleiotropy assessment, and Cochran Q and leave-one-out methods for heterogeneity testing. The forward MR analysis indicated a significant causal relationship between TL and osteonecrosis, suggesting that genetically predicted shorter TL is associated with an elevated risk of developing osteonecrosis (OR = 0.611, 95% confidence interval 0.394-0.948, P = .028). The reverse MR analysis revealed no significant influence of osteonecrosis on TL (OR = 0.999, 95% confidence interval 0.994-1.005, P = .802). Analyses for heterogeneity and horizontal pleiotropy yielded robust results. Our study demonstrates that individuals with shorter TL have an increased risk of developing osteonecrosis, whereas osteonecrosis has no effect on TL.

Exosomal miR-150 derived from BMSCs inhibits TNF-α-mediated osteoblast apoptosis in osteonecrosis of the femoral head by GREM1/NF-κB signaling

Aim: The purpose of this study was to investigate the functions of exosomal miR-150 derived from bone marrow mesenchymal stem cells in osteonecrosis of the femoral head (ONFH). Materials & methods: Cell viability and apoptosis were detected using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and flow cytometry. Alizarin red staining was performed to detect calcium deposits. A rat model was established to assess the effects of exosomal miR-150 on ONFH in vivo. Results: Exosomes or exosomal miR-150 derived from bone marrow mesenchymal stem cells inhibited TNF-α-induced osteoblast apoptosis and promoted osteogenic differentiation and autophagy. Exosomal miR-150 suppressed apoptosis and induced autophagy in TNF-α-treated osteoblasts by regulating the GREM1/NF-κB axis. Exosomal miR-150 also improved the pathological features of ONFH in vivo. Conclusion: Exosomal miR-150 alleviates ONFH by mediating the GREM1/NF-κB axis. This study provides a potential therapeutic strategy for ONFH.

Upregulation of osteoprotegerin inhibits tert-butyl hydroperoxide-induced apoptosis of human chondrocytes

Necrosis of the femoral head (NFH) is an orthopedic disease characterized by a severe lack of blood supply to the femoral head and a marked increase in intraosseous pressure. NFH is associated with numerous factors, such as alcohol consumption and hormone levels. The present study focused on the expression levels of osteoprotegerin (OPG) in NFH and the effect of OPG overexpression on chondrocyte apoptosis. The results demonstrated that OPG expression was markedly decreased in the femoral head of patients with NFH compared with normal femoral heads. Lentivirus-mediated overexpression of OPG in human chondrocytes reversed the decrease in cell viability and the increase in reactive oxygen species production induced by an oxidative stress-inducing factor, tert-butyl hydroperoxide. Flow cytometry and TUNEL assays revealed that OPG overexpression inhibited the apoptosis of chondrocytes. In addition, it was revealed that OPG exerted its anti-apoptotic effect mainly by promoting Bcl-2 expression and Akt phosphorylation and inhibiting caspase-3 cleavage and Bax expression. The present study revealed that OPG may be an important regulator of NFH.