Extracellular vesicles (EVs), including exosomes, microvesicles, and apoptotic bodies, play an important role in cellular communication during skeletal growth and homeostasis. Bioactive molecules carried by EVs are transported to neighboring and distant cells to trigger a series of signaling cascades influencing bone homeostasis. The bioactive activities of osteoclast-derived EVs include regulation of osteoclastogenesis and osteoclast–osteoblast communication. As osteoclast-derived EVs have the potential to regulate osteoclasts and osteoblasts, their application in osteoporosis and other bone metabolic disorders is currently under investigation. However, very few reviews of osteoclast-derived EVs in bone remodeling regulation have yet been published. This article aims to review recent advances in this field, summarizing a new regulator of osteoclastogenesis and osteoclast–osteoblast communication mediated by osteoclast-derived EVs. We will analyze the major challenges in the field and potential for the therapeutic application of EVs.
Osteoporosis is a metabolic bone disease characterized by a decrease in bone mass and degradation of the bone microstructure, which increases bone fragility and fracture risk. However, the molecular mechanisms of osteoporosis remain unclear. Long non-coding RNAs (lncRNAs) have become important epigenetic regulators controlling the expression of genes and affecting multiple biological processes. Accumulating evidence of the involvement of lncRNAs in bone remolding has increased understanding of the molecular mechanisms underlying osteoporosis. This review aims to summarize recent progress in the elucidation of the role of lncRNAs in bone remodeling, and how it contributes to osteoblast and osteoclast function. This knowledge will facilitate the understanding of lncRNA roles in bone biology and shed new light on the modulation and potential treatment of osteoporosis.
Background
At present, it is unclear which device (uncemented or cemented total hip arthroplasty [UTA or CTA, respectively]) is more suitable for the conversion of a failed proximal femoral nail anti-rotation (PFNA). The aim of this review was to assess the outcomes of failed PFNAs converted to a UTA or CTA device in elderly individuals with intertrochanteric femoral fractures (IFFs).
Methods
Two hundred fifty-eight elderly individuals (258 hips) with IFFs who underwent a conversion to a UTA or CTA device following failed PFNAs during 2007–2017 were retrospectively identified from the China Southern Medical Centre (CSMC) database. The primary endpoint was the Harris Hip Score (HHS); secondary endpoint was the key orthopaedic complication rate.
Results
The median follow-up was 65 months (60–69 months). Significant distinctions were observed (87.26 ± 16.62 for UTA vs. 89.32 ± 16.08 for CTA, p = 0.021; 86.61 ± 12.24 for symptomatic UTA vs. 88.68 ± 13.30 for symptomatic CTA, p = 0.026). A significant difference in the overall key orthopaedic complication rate was detected (40.8% [40/98] vs. 19.0% [19/100], p = 0.001). Apparent distinctions were detected in terms of the rate of revision, loosening, and periprosthetic fracture (11.2% for UTA vs 3.0% for CTA, p = 0.025; 13.2% for UTA vs 5.0% for CTA, p = 0.043; 10.2% for UTA vs 3.0% for CTA, p = 0.041, respectively).
Conclusion
For elderly individuals with IFFs who suffered a failed PFNA, CTA devices may have a noteworthy advantage in regard to the revision rate and the rate of key orthopaedic complications compared with UTA devices, and CTA revision should be performed as soon as possible, regardless of whether these individuals have symptoms.
In recent years, research on wound healing has become increasingly in-depth, but therapeutic effects are still not satisfactory. Occasionally, pathological tissue repair occurs. Influencing factors have been proposed, but finding the turning point between normal and pathological tissue repair is difficult. Therefore, we focused our attention on the most basic level of tissue repair: fibroblasts. Fibroblasts were once considered terminally differentiated cells that represent a single cell type, and their heterogeneity was not studied until recently. We believe that subpopulations of fibroblasts play different roles in tissue repair, resulting in different repair results, such as the formation of normal scars in physiological tissue repair and fibrosis or ulcers in pathological tissue repair. It is also proposed that scarless healing can be achieved by regulating fibroblast subpopulations.
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