Preclinical proof of principle for orally delivered Th17 antagonist miniproteins.

Interleukin (IL)-23 and IL-17 are well-validated therapeutic targets in autoinflammatory diseases. Antibodies targeting IL-23 and IL-17 have shown clinical efficacy but are limited by high costs, safety risks, lack of sustained efficacy, and poor patient convenience as they require parenteral administration. Here, we present designed miniproteins inhibiting IL-23R and IL-17 with antibody-like, low picomolar affinities at a fraction of the molecular size. The minibinders potently block cell signaling in vitro and are extremely stable, enabling oral administration and low-cost manufacturing. The orally administered IL-23R minibinder shows efficacy better than a clinical anti-IL-23 antibody in mouse colitis and has a favorable pharmacokinetics (PK) and biodistribution profile in rats. This work demonstrates that orally administered de novo-designed minibinders can reach a therapeutic target past the gut epithelial barrier. With high potency, gut stability, and straightforward manufacturability, de novo-designed minibinders are a promising modality for oral biologics.

Design of cell-type-specific hyperstable IL-4 mimetics via modular de novo scaffolds.

The interleukin-4 (IL-4) cytokine plays a critical role in modulating immune homeostasis. Although there is great interest in harnessing this cytokine as a therapeutic in natural or engineered formats, the clinical potential of native IL-4 is limited by its instability and pleiotropic actions. Here, we design IL-4 cytokine mimetics (denoted Neo-4) based on a de novo engineered IL-2 mimetic scaffold and demonstrate that these cytokines can recapitulate physiological functions of IL-4 in cellular and animal models. In contrast with natural IL-4, Neo-4 is hyperstable and signals exclusively through the type I IL-4 receptor complex, providing previously inaccessible insights into differential IL-4 signaling through type I versus type II receptors. Because of their hyperstability, our computationally designed mimetics can directly incorporate into sophisticated biomaterials that require heat processing, such as three-dimensional-printed scaffolds. Neo-4 should be broadly useful for interrogating IL-4 biology, and the design workflow will inform targeted cytokine therapeutic development.

Mechanistic computational modeling of monospecific and bispecific antibodies targeting interleukin-6/8 receptors.

The spread of cancer from organ to organ (metastasis) is responsible for the vast majority of cancer deaths; however, most current anti-cancer drugs are designed to arrest or reverse tumor growth without directly addressing disease spread. It was recently discovered that tumor cell-secreted interleukin-6 (IL-6) and interleukin-8 (IL-8) synergize to enhance cancer metastasis in a cell-density dependent manner, and blockade of the IL-6 and IL-8 receptors (IL-6R and IL-8R) with a novel bispecific antibody, BS1, significantly reduced metastatic burden in multiple preclinical mouse models of cancer. Bispecific antibodies (BsAbs), which combine two different antigen-binding sites into one molecule, are a promising modality for drug development due to their enhanced avidity and dual targeting effects. However, while BsAbs have tremendous therapeutic potential, elucidating the mechanisms underlying their binding and inhibition will be critical for maximizing the efficacy of new BsAb treatments. Here, we describe a quantitative, computational model of the BS1 BsAb, exhibiting how modeling multivalent binding provides key insights into antibody affinity and avidity effects and can guide therapeutic design. We present detailed simulations of the monovalent and bivalent binding interactions between different antibody constructs and the IL-6 and IL-8 receptors to establish how antibody properties and system conditions impact the formation of binary (antibody-receptor) and ternary (receptor-antibody-receptor) complexes. Model results demonstrate how the balance of these complex types drives receptor inhibition, providing important and generalizable predictions for effective therapeutic design.

Pan-histone deacetylase inhibitor vorinostat suppresses osteoclastic bone resorption through modulation of RANKL-evoked signaling and ameliorates ovariectomy-induced bone loss.

BACKGROUND: Estrogen deficiency-mediated hyperactive osteoclast represents the leading role during the onset of postmenopausal osteoporosis. The activation of a series of signaling cascades triggered by RANKL-RANK interaction is crucial mechanism underlying osteoclastogenesis. Vorinostat (SAHA) is a broad-spectrum pan-histone deacetylase inhibitor (HDACi) and its effect on osteoporosis remains elusive. METHODS: The effects of SAHA on osteoclast maturation and bone resorptive activity were evaluated using in vitro osteoclastogenesis assay. To investigate the effect of SAHA on the osteoclast gene networks during osteoclast differentiation, we performed high-throughput transcriptome sequencing. Molecular docking and the assessment of RANKL-induced signaling cascades were conducted to confirm the underlying regulatory mechanism of SAHA on the action of RANKL-activated osteoclasts. Finally, we took advantage of a mouse model of estrogen-deficient osteoporosis to explore the clinical potential of SAHA. RESULTS: We showed here that SAHA suppressed RANKL-induced osteoclast differentiation concentration-dependently and disrupted osteoclastic bone resorption in vitro. Mechanistically, SAHA specifically bound to the predicted binding site of RANKL and blunt the interaction between RANKL and RANK. Then, by interfering with downstream NF-κB and MAPK signaling pathway activation, SAHA negatively regulated the activity of NFATc1, thus resulting in a significant reduction of osteoclast-specific gene transcripts and functional osteoclast-related protein expression. Moreover, we found a significant anti-osteoporotic role of SAHA in ovariectomized mice, which was probably realized through the inhibition of osteoclast formation and hyperactivation. CONCLUSION: These data reveal a high affinity between SAHA and RANKL, which results in blockade of RANKL-RANK interaction and thereby interferes with RANKL-induced signaling cascades and osteoclastic bone resorption, supporting a novel strategy for SAHA application as a promising therapeutic agent for osteoporosis.

Melatonin rescues the mitochondrial function of bone marrow-derived mesenchymal stem cells and improves the repair of osteoporotic bone defect in ovariectomized rats.

Osteoporotic bone defects, a severe complication of osteoporosis, are distinguished by a delayed bone healing process and poor repair quality. While bone marrow-derived mesenchymal stem cells (BMMSCs) are the primary origin of bone-forming osteoblasts, their mitochondrial function is impaired, leading to inadequate bone regeneration in osteoporotic patients. Melatonin is well-known for its antioxidant properties and regulation on bone metabolism. The present study postulated that melatonin has the potential to enhance the repair of osteoporotic bone defects by restoring the mitochondrial function of BMMSCs. In vitro administration of melatonin at varying concentrations (0.01, 1, and 100 µM) demonstrated a significant dose-dependent improvement in the mitochondrial function of BMMSCs obtained from ovariectomized rats (OVX-BMMSCs), as indicated by an elevation in mitochondrial membrane potential, adenosine triphosphate synthesis and expression of mitochondrial respiratory chain factors. Melatonin reduced the level of mitochondrial superoxide by activating the silent information regulator type 1 (SIRT1) and its downstream antioxidant enzymes, particularly superoxide dismutase 2 (SOD2). The protective effects of melatonin were found to be nullified upon silencing of Sirt1 or Sod2, underscoring the crucial role of the SIRT1-SOD2 axis in the melatonin-induced enhancement of mitochondrial energy metabolism in OVX-BMMSCs. To achieve a sustained and localized release of melatonin, silk fibroin scaffolds loaded with melatonin (SF@MT) were fabricated. The study involved the surgical creation of bilateral femur defects in OVX rats, followed by the implantation of SF@MT scaffolds. The results indicated that the application of melatonin partially restored the mitochondrial energy metabolism and osteogenic differentiation of OVX-BMMSCs by reinstating mitochondrial redox homeostasis. These findings suggest that the localized administration of melatonin through bone implants holds potential as a therapeutic approach for addressing osteoporotic bone defects.

Heat stress-induced NO enhanced perylenequinone biosynthesis of Shiraia sp. via calcium signaling pathway.

Perylenequinones (PQs) are natural photosensitizing compounds used as photodynamic therapy, and heat stress (HS) is the main limiting factor of mycelial growth and secondary metabolism of fungi. This study aimed to unravel the impact of HS-induced Ca2+ and the calcium signaling pathway on PQ biosynthesis of Shiraia sp. Slf14(w). Meanwhile, the intricate interplay between HS-induced NO and Ca2+ and the calcium signaling pathway was investigated. The outcomes disclosed that Ca2+ and the calcium signaling pathway activated by HS could effectively enhance the production of PQs in Shiraia sp. Slf14(w). Further investigations elucidated the specific mechanism through which NO signaling molecules induced by HS act upon the Ca2+/CaM (calmodulin) signaling pathway, thus propelling PQ biosynthesis in Shiraia sp. Slf14(w). This was substantiated by decoding the downstream positioning of the CaM/CaN (calcineurin) pathway in relation to NO through comprehensive analyses encompassing transcript levels, enzyme assays, and the introduction of chemical agents. Concurrently, the engagement of Ca2+ and the calcium signaling pathway in heat shock signaling was also evidenced. The implications of our study underscore the pivotal role of HS-induced Ca2+ and the calcium signaling pathway, which not only participate in heat shock signal transduction but also play an instrumental role in promoting PQ biosynthesis. Consequently, our study not only enriches our comprehension of the mechanisms driving HS signaling transduction in fungi but also offers novel insights into the PQ synthesis paradigm within Shiraia sp. Slf14(w). KEY POINTS: • The calcium signaling pathway was proposed to participate in PQ biosynthesis under HS. • HS-induced NO was revealed to act upon the calcium signaling pathway for the first time.

Kyphoplasty is associated with reduced mortality risk for osteoporotic vertebral compression fractures: a systematic review and meta-analysis.

BACKGROUND: Vertebral augmentation, such as vertebroplasty (VP) or kyphoplasty (KP), has been utilized for decades to treat OVCFs; however, the precise impact of this procedure on reducing mortality risk remains a topic of controversy. This study aimed to explore the potential protective effects of vertebral augmentation on mortality in patients with osteoporotic vertebral compression fractures (OVCFs) using a large-scale meta-analysis. MATERIALS AND METHODS: Cochrane Library, Embase, MEDLINE, PubMed and Web of Science databases were employed for literature exploration until May 2023. The hazard ratios (HRs) and 95% confidence intervals (CIs) were utilized as a summary statistic via random-effect models. Statistical analysis was executed using Review Manager 5.3 software. RESULTS: After rigorous screening, a total of five studies with substantial sample sizes were included in the quantitative meta-analysis. The total number of participants included in the study was an 2,421,178, comprising of 42,934 cases of vertebral augmentation and 1,991,244 instances of non-operative management. The surgical intervention was found to be significantly associated with an 18% reduction in the risk of mortality (HR 0.82; 95% CI 0.78, 0.85). Subgroup analysis revealed a remarkable 71% reduction in mortality risk following surgical intervention during short-term follow-up (HR 0.29; 95% CI 0.26, 0.32). Furthermore, KP exhibited a superior and more credible decrease in the risk of mortality when compared to VP treatment. CONCLUSIONS: Based on a comprehensive analysis of large samples, vertebral augmentation has been shown to significantly reduce the mortality risk associated with OVCFs, particularly in the early stages following fractures. Furthermore, it has been demonstrated that KP is more reliable and effective than VP in terms of mitigating mortality risk.

Effect of basal metabolic rate on rheumatoid arthritis: a Mendelian randomization study.

PURPOSE: Basal metabolic rate (BMR) as one of the most basic and significant indicators of metabolism has been associated with human health. Previous studies showed that the development of rheumatoid arthritis (RA) is linked to BMR; however, the causal relationship between BMR and RA is unknown. Thus, we aimed to explore the causal relationship between BMR and RA as well as RA-related factors. METHODS: Mendelian randomization (MR) analysis was performed on collected genome-wide association studies information. The effect of horizontal pleiotropy was detected by MR-PRESSO and MR-Radial. Five MR analysis methods were applied, including inverse variance weighted, MR-Egger, weighted median, weighted mode, and simple mode. Four sensitivity analysis methods were used for the validation of the significant MR analysis results. A two-component mixture of regressions method was additionally used to validate single nucleotide polymorphisms and to verify results. RESULTS: Genetically, there is a causal effect of BMR on overall RA (odds ratio = 1.25, 95% confidence interval: 1.07-1.47, PIVW = .006), seropositive RA (odds ratio = 1.20, 95% confidence interval: 1.01-1.44, PIVW = .035), and seronegative RA (odds ratio = 1.36, 95% confidence interval: 1.04-1.78, PIVW = .023). Sensitivity analyses validated the robustness of the above associations. No evidence supported the effect of RA on BMR. Moreover, BMR showed no causal relationship with rheumatoid factor, C-reactive protein, erythrocyte sedimentation rate, interleukin-1ß, tumor necrosis factor-α, and matrix metallopeptidase 3. CONCLUSION: MR results implied the causal effect of BMR on RA and raised our attention to the importance of BMR in RA's pathology.

Lumbar lordosis and sacral slope do not differ in two types of postoperative lumbar disc re-herniation: a cross-sectional observational study.

BACKGROUND: To identify the differences of lumbar lordosis (LL) and sacral slope (SS) angles between two types of postoperative lumbar disc re-herniation, including the recurrence of same level and adjacent segment herniation (ASH). METHODS: We searched the medical records of lumbar disc herniation (LDH) patients with re-herniation with complete imaging data (n = 58) from January 1, 2013 to December 30, 2020 in our hospital. After matching for age and sex, 58 patients with LDH without re-herniation from the same period operated by the same treatment group in our hospital were served as a control group. Re-herniation patients were divided into two groups, same-level recurrent lumbar disc herniation group (rLDHG) and adjacent segment herniation group with or without recurrence (ASHG). The preoperative, postoperative and one month after operation LL and SS were measured on standing radiographs and compared with the control group by using t-test, ANOVA, and rank-sum test. Next, we calculated the odds ratios (ORs) by unconditional logistic regression, progressively adjusted for other confounding factors. RESULTS: Compared with the control group, the postoperative LL and SS were significantly lower in LDH patients with re-herniation. However, there were no differences in LL and SS between ASHG and rLDHG at any stage. After progressive adjustment for confounding factors, no matter what stage is, LL and SS remained unassociated with the two types of re-herniation. CONCLUSIONS: Low postoperative LL and SS angles are associated with degeneration of the remaining disc. Low LL and SS may be independent risk factors for re-herniation but cannot determine type of recurrence (same or adjacent disc level).

PI3K/AKT/mTORC1 signalling pathway regulates MMP9 gene activation via transcription factor NF-κB in mammary epithelial cells of dairy cows.

Matrix metalloproteinase 9 (MMP9) plays a pivotal role in mammary ductal morphogenesis, angiogenesis and glandular tissue architecture remodeling. However, the molecular mechanism of MMP9 expression in mammary epithelial cells of dairy cows remains unclear. This study aimed to explore the underlying mechanism of MMP9 expression. In this study, to determine whether the PI3K/AKT/mTORC1/NF-κB signalling pathway participates in the regulation of MMP9 expression, we treated mammary epithelial cells with specific pharmacological inhibitors of PI3K (LY294002), mTORC1 (Rapamycin) or NF-κB (Celastrol), respectively. Western blotting results indicated that LY294002, Rapamycin and Celastrol markedly decreased MMP9 expression and P65 nuclear translocation. Furthermore, we found that NF-κB (P65) overexpression resulted in elevated expression of MMP9 protein and activation of MMP9 promoter. In addition, we observed that Celastrol markedly decreases P65-overexpression-induced MMP9 promoter activity. Moreover, the results of the promoter assay indicated that the core regulation sequence for MMP9 promoter activation may be located at -420 ∼ -80 bp downstream from the transcription start site. These observations indicated that the PI3K/AKT/mTORC1 signalling pathway is involved in MMP9 expression by regulating MMP9 promoter activity via NF-κB in the mammary epithelial cells of dairy cows.

Bioactive prenylated c6-c3 derivatives from the roots of Illicium brevistylum.

Three new prenylated C6-C3 compounds (1-3), together with two known prenylated C6-C3 compounds (4-5) and one known C6-C3 derivative (6), were isolated from the roots of Illicium brevistylum A. C. Smith. The structures of 1-3 were elucidated by spectroscopic methods including 1D and 2D NMR, HRESIMS, CD experiments and ECD calculations. The structure of illibrefunone A (1) was confirmed by single-crystal X-ray diffraction analysis. All compounds were evaluated in terms of their anti-inflammatory potential on nitric oxide (NO) generation in lipopolysaccharide-stimulated murine RAW264.7 macrophages and murine BV2 microglial cells, antiviral activity against Coxsackievirus B3 (CVB3) and influenza virus A/Hanfang/359/95 (H3N2). Compounds 3 and 4 exhibited potent inhibitory effects on the production of NO in RAW 264.7 cells with IC50 values of 20.57 and 12.87 µM respectively, which were greater than those of dexamethasone (positive control). Compounds 1 and 4-6 exhibited weak activity against Coxsackievirus B3, with IC50 values ranging from 25.87 to 33.33 µM.

Spermidine protects cartilage from IL-1ß-mediated ferroptosis.

Rheumatoid arthritis is characterized by a burst of inflammation, the destruction of cartilage and the abundant release of inflammatory factors such as IL-1ß. Thus, the effect of IL-1ß on cartilage was examined in this study. IL-1ß could cause lipid peroxidation and disturbances in iron metabolism by increasing the expression of NCOA4 and decreasing the expression of FTH, which also induced ferritinophagy. In addition, the expression of the key antioxidant proteins SLC7A11 and GPX4 was inhibited by IL-1ß, resulting in ferroptosis in chondrocytes. Spermidine (SPD), a low-molecular-weight aliphatic nitrogen-containing compound that widely exists in animals, has been reported to be an antioxidant. In our study, we found that SPD could inhibit ferritinophagy and reverse the decrease in the expression of SLC7A11 and GPX4. Therefore, we uncovered one of the molecular mechanisms of cartilage destruction and inflammation and provide a potential polyamine for the treatment of RA.

A biphasic calcium phosphate/acylated methacrylate gelatin composite hydrogel promotes osteogenesis and bone repair.

PURPOSE/AIM: Bone defects caused by trauma, tumors, congenital malformation, or inflammation are very common in orthopedics. In recent years, mimicking the composition and structure of natural bone tissue has become a hot topic in biomaterial research, with the aim of developing an ideal biomaterial for bone defect transplantation. Here, the feasibility of a biphasic calcium phosphate (BCP)/acylated methacrylate gelatin (GelMA) composite hydrogel to repair bone defects was evaluated in vitro and in rats. MATERIALS AND METHODS: The biocompatibility of a biphasic calcium phosphate (BCP)/acylated methacrylate gelatin (GelMA) composite hydrogel was evaluated by cytoskeleton staining, live/dead cell staining and cell proliferation assays. The in vitro osteogenic activities of the composite hydrogel were evaluated by alkaline phosphatase and alizarin red staining, as well as osteogenic gene expression analysis at both transcript and protein levels. The in vivo bone repair activities were evaluated using the rat skull defect model. RESULTS: The BCP/GelMA composite hydrogel displayed excellent biocompatibility and promoted osteogenesis of bone marrow mesenchymal stem cells in vitro. In addition, the BCP/GelMA composite hydrogel markedly promoted new bone formation in the rat skull-defect model. CONCLUSIONS: BCP/GelMA composite hydrogel may be an effective artificial material for bone tissue engineering.

Prolactin regulates RANKL expression via signal transducer and activator of transcription 5a signaling in mammary epithelial cells of dairy cows.

Receptor of activated nuclear factor kappa B ligand (RANKL) is regulated by prolactin in the mammary gland. However, the intrinsic molecular mechanism is not well understood. Herein, mammary epithelial cells (MECs) of dairy cows were isolated to characterize the molecular mechanism of prolactin in vitro. We demonstrated that prolactin stimulation increased the expression of RANKL in MECs. Moreover, the expression of RANKL induced by prolactin was inhibited by the prolactin receptor or signal transducer and activator of transcription 5A (STAT5a) knockdown. Furthermore, prolactin markedly increased RANKL-Luciferase reporter activity in MECs. We identified a putative gamma-interferon activated site (GAS) in the region between residues -883 to -239 bp of the RANKL promoter. Subsequently, we found that the mutated GAS sequence failed to respond to prolactin stimulation. In addition, STAT5a knockdown markedly decreased prolactin-stimulated RANKL promoter activity. Western blot results revealed that RANKL overexpression markedly decreased the STAT5a phosphorylation level in MECs. These findings indicate that prolactin could regulate RANKL promoter activity via STAT5a, contributing to increased RANKL expression in MECs. RANKL may have a negative regulatory effect on STAT5a activity.

Transcriptome Changes Reveal the Toxic Mechanism of Cadmium and Lead Combined Exposure on Silk Production and Web-Weaving Behavior of Spider A. ventricosus.

The combined exposure of multiple metals imposes a substantial burden on the ecophysiological functions in organisms; however, the precise mechanism(s) remains largely unknown. Here, adult female A. ventricosus were exposed to single and combined exposure to cadmium (Cd) and lead (Pb) through the food chain. The aim was to explore the combined toxicity of these metals on silk production and web-weaving behavior at physiological, cellular morphological, and transcriptomic levels. The Cd and Pb combined exposure significantly inhibited the ability of silk production and web-weaving, including reduced silk fiber weight and diameter of single strands, lowered weaving position, induced nocturnal weaving, and increased instances of no-web, and showed a dose-response relationship on the Cd and Pb bioaccumulation. Concurrently, severe oxidative stress and degenerative changes in cells were observed. In addition, the combined pollution of Cd and Pb demonstrated synergistic effects, influenced by variations in concentration, on the enrichment of metals, inhibition of silk weight, oxidative damage, and cellular degeneration. At the transcriptome level, the upregulated ampullate spidroin genes and downregulated amino acid anabolic genes, upregulated Far genes and downregulated cytoskeleton-related TUBA genes, and overexpressed AChE and Glu genes may tend to present promising potential as biomarkers for silk protein synthesis, cellular degeneration, and neurotransmitter induction. This study offers an enormous capability for a comprehensive understanding of the eco-toxicological effects and mechanisms of multiheavy metals pollution.

Identification and characterization of a novel high-activity amylosucrase from Salinispirillum sp. LH10-3-1.

In this study, a novel high-activity amylosucrase from Salinispirillum sp. LH10-3-1 (SaAS) was identified and characterized. The recombinant enzyme was determined as a monomer with a molecular mass of 75 kDa. SaAS protein exhibited the maximum total and polymerization activities at pH 9.0 and maximum hydrolysis activity at pH 8.0. The optimum temperature for total, polymerization, and hydrolysis activities were 40, 40, and 45 °C, respectively. Under the optimal pH and temperature, SaAS had a specific activity of 108.2 U/mg. SaAS also showed excellent salt tolerance and could retain 77.4% of its original total activity at 4.0 M NaCl. The addition of Mg2+, Ba2+, and Ca2+ enhanced the total activity of SaAS. When the conversion of 0.1 M and 1.0 M sucrose was catalyzed at pH 9.0 and 40 °C for 24 h, the ratios of hydrolysis, polymerization, and isomerization reactions were 11.9:77.4:10.7 and 15.3:53.5:31.2, respectively. The α-arbutin yield of 60.3% was achieved from 20 mM sucrose and 5 mM hydroquinone catalyzed by SaAS. KEY POINTS: • A novel amylosucrase from Salinispirillum sp. LH10-3-1 (SaAS) was characterized. • SaAS has the highest specific enzyme activity among all known amylosucrase. • SaAS has hydrolysis, polymerization, isomerization, and glucosyltransferase activities.

Engineered bispecific antibodies targeting the interleukin-6 and -8 receptors potently inhibit cancer cell migration and tumor metastasis.

Simultaneous inhibition of interleukin-6 (IL-6) and interleukin-8 (IL-8) signaling diminishes cancer cell migration, and combination therapy has recently been shown to synergistically reduce metastatic burden in a preclinical model of triple-negative breast cancer. Here, we have engineered two novel bispecific antibodies that target the IL-6 and IL-8 receptors to concurrently block the signaling activity of both ligands. We demonstrate that a first-in-class bispecific antibody design has promising therapeutic potential, with enhanced selectivity and potency compared with monoclonal antibody and small-molecule drug combinations in both cellular and animal models of metastatic triple-negative breast cancer. Mechanistic characterization revealed that our engineered bispecific antibodies have no impact on cell viability, but profoundly reduce the migratory potential of cancer cells; hence they constitute a true anti-metastatic treatment. Moreover, we demonstrate that our antibodies can be readily combined with standard-of-care anti-proliferative drugs to develop effective anti-cancer regimens. Collectively, our work establishes an innovative metastasis-focused direction for cancer drug development.

Cellular senescence in skeletal disease: mechanisms and treatment.

The musculoskeletal system supports the movement of the entire body and provides blood production while acting as an endocrine organ. With aging, the balance of bone homeostasis is disrupted, leading to bone loss and degenerative diseases, such as osteoporosis, osteoarthritis, and intervertebral disc degeneration. Skeletal diseases have a profound impact on the motor and cognitive abilities of the elderly, thus creating a major challenge for both global health and the economy. Cellular senescence is caused by various genotoxic stressors and results in permanent cell cycle arrest, which is considered to be the underlying mechanism of aging. During aging, senescent cells (SnCs) tend to aggregate in the bone and trigger chronic inflammation by releasing senescence-associated secretory phenotypic factors. Multiple signalling pathways are involved in regulating cellular senescence in bone and bone marrow microenvironments. Targeted SnCs alleviate age-related degenerative diseases. However, the association between senescence and age-related diseases remains unclear. This review summarises the fundamental role of senescence in age-related skeletal diseases, highlights the signalling pathways that mediate senescence, and discusses potential therapeutic strategies for targeting SnCs.

Qualitative and quantitative diagnosis of intramuscular hemangioma subtypes: Diagnostic performance comparison of ESWAN and conventional MRI.

BACKGROUND: Preoperative identification of intramuscular hemangioma (IMH) subtypes (capillary hemangioma, cavernous hemangioma, and mixed hemangioma) is urgently necessary. Enhanced T2*-weighted angiography (ESWAN) is sensitive to vessels and metabolites and can be used to diagnose IMH subtypes. PURPOSE: To compare the diagnostic performances of ESWAN and conventional magnetic resonance imaging (MRI) for qualitative and quantitative diagnosis of IMH subtypes. MATERIAL AND METHODS: In total, 23 patients with IMHs were examined using conventional MRI and ESWAN. The signal intensity ratios (SIRs) of conventional MRI and ESWAN were measured. RESULTS: There was no significant difference for volume among the three subtypes (P = 0.124, P = 0.145). Various shapes and MRI signals were shown in the three subtypes of IMH. There was no significant difference for SIRs of conventional MRI (P = 0.558, P = 0.259, P = 0.385, P = 0.347). However, there was a significant difference for SIRs of ESWAN parameters (P = 0.050, P < 0.001, P = 0.005, P = 0.002). Capillary hemangiomas can be diagnosed when R2* SIR is <0.912 and intratumoral susceptibility signal (ITSS) percentage is <29.085%. Cavernous hemangiomas should be considered when R2* SIR is >0.912, ITSS percentage >35.226%, and phase SIR >2.536. In addition, mixed hemangiomas should be considered when T2* SIR is >0.662 and R2* SIR <1.618. CONCLUSION: Conventional MRI can only display the volume, shape, and signal of IMHs. 3D-MinIP imaging of ESWAN can show the veins and minor hemorrhage. SIRs of ESWAN parameters including T2* value, R2* value, phase value, and percentage of ITSS can be used to quantitatively diagnose capillary hemangiomas, cavernous hemangiomas, and mixed hemangiomas.

Thoracolumbar fascia injury in osteoporotic vertebral fracture: the important concomitant damage.

BACKGROUND: Thoracolumbar fascia injury (FI) is rarely discussed in osteoporotic vertebral fracture (OVF) patients in previous literature and it is usually neglected and treated as an unmeaning phenomenon. We aimed to evaluate the characteristics of the thoracolumbar fascia injury and further discuss its clinical significance in the treatment of kyphoplasty for osteoporotic vertebral fracture (OVF) patients. METHODS: Based on the presence or absence of FI, 223 OVF patients were divided into two groups. The demographics of patients with and without FI were compared. The visual analogue scale and Oswestry disability index scores were compared preoperatively and after PKP treatment between these groups. RESULTS: Thoracolumbar fascia injuries were observed in 27.8% of patients. Most FI showed a multi-level distribution pattern which involved a mean of 3.3 levels. Location of fractures, severity of fractures and severity of trauma were significantly different between patients with and without FI. In further comparison, severity of trauma was significantly different between patients with severe and non-severe FI. In patients with FI, VAS and ODI scores of 3 days and 1 month after PKP treatment were significantly worse compared to those without FI. It showed the same trend in VAS and ODI scores in patients with severe FI when compared to those patients with non-severe FI. CONCLUSIONS: FI is not rare in OVF patients and presents multiple levels of involvement. The more serious trauma suffered, the more severe thoracolumbar fascia injury presented. The presence of FI which was related to residual acute back pain significantly affected the effectiveness of PKP in treating OVFs. TRIAL REGISTRATION: retrospectively registered.