Search Results (1,361)

Heterotopic ossification (HO) refers to the pathological formation of bone in soft tissues, typically following trauma, surgical procedures, or as a result of genetic disorders. Notably, injuries to the central nervous system significantly increase the risk of HO, a condition referred to as neurogenic HO (NHO). This review outlines the cellular and molecular mechanisms driving HO, focusing on the inflammatory response, progenitor cell reprogramming, and current treatment strategies. HO is primarily fuelled by a prolonged and dysregulated inflammatory response, characterized by sustained expression of osteoinductive cytokines secreted by M1 macrophages. These cytokines promote the aberrant differentiation of fibro-adipogenic progenitor cells (FAPs) into osteoblasts, leading to ectopic mineralization. Additional factors such as hypoxia, BMP signalling, and mechanotransduction pathways further contribute to extracellular matrix (ECM) remodelling and osteogenic reprogramming of FAPs. In the context of NHO, neuroendocrine mediators enhance ectopic bone formation by influencing both local inflammation and progenitor cell fate decisions. Current treatment options such as nonsteroidal anti-inflammatory drugs (NSAIDs), radiation therapy, and surgical excision offer limited efficacy and are associated with significant risks. Novel therapeutic strategies targeting inflammation, neuropeptide signalling, and calcium metabolism may offer more effective approaches to preventing or mitigating HO progression. Full article

This study aimed to compare the performance of three hydroxyapatite–β-tricalcium phosphate (HA–β-TCP) collagen composite grafts in a canine model for extraction socket preservation. Eight mongrel dogs underwent atraumatic bilateral mandibular premolar extraction, and sockets were randomly grafted with HBC28 (20% high-crystalline HA, 80% β-TCP bovine collagen), HBC37 (30% HA, 70% β-TCP, bovine collagen), or HPC64 (60% HA, 40% β-TCP, porcine collagen). Grafts differed in their HA–β-TCP ratio and collagen origin and content. Animals were sacrificed at 4 and 12 weeks, and the healing sites were evaluated using micro-computed tomography (micro-CT) and histological analysis. At 12 weeks, all groups showed good socket maintenance with comparable new bone formation. However, histological analysis revealed that HBC28 had significantly higher residual graft volume, while HPC64 demonstrated more extensive graft resorption. Histomorphometric analysis confirmed these findings, with statistically significant differences in residual graft area and bone volume fraction. No inflammatory response or adverse tissue reactions were observed in any group. These results suggest that all three HA–β-TCP collagen composites are biocompatible and suitable for socket preservation, with varying resorption kinetics influenced by graft composition. Selection of graft material may thus be guided by the desired rate of replacement by new bone. Full article

Postmenopausal osteoporosis is estrogen-dependent and results in an imbalance between bone formation and resorption. The approved therapy is intended to reduce the risk and consequences of fractures, but still has a number of contraindications and associated adverse effects. Recently, oxytocin has been shown to have an anabolic effect on bone tissue, increasing the production of osteoblasts and inhibiting the activity of osteoclasts. Thus, this study aimed to examine the potential of oxytocin as a biomarker and therapeutic agent for postmenopausal osteoporosis. A PubMed search yielded 16 articles upon analysis of the inclusion and exclusion criteria. The results showed that, compared to women in the same age group without bone loss, those diagnosed with osteoporosis exhibited lower blood oxytocin levels, possibly related to a greater tendency towards fractures. The administration of oxytocin could be a promising strategy to enhance bone quality and, consequently, to reduce the incidence of fragility fractures; however, no human studies have been conducted regarding its use as a possible treatment. Thus, it is essential to increase the number of clinical trials in women with ovarian dysfunction and bone loss, in which oxytocin could become a viable therapeutic alternative. Full article

Background: The role of collagen membrane fixation during guided bone regeneration (GBR) remains debatable, particularly in post-extraction sockets with buccal defects and concomitant immediate implant placement. This study evaluated whether or not fixation with titanium pins improved regenerative outcomes. Methods: Six adult Beagle dogs received bilateral extractions of the fourth mandibular premolars. An implant was immediately placed in both the distal alveoli, and standardized buccal bone defects (5 mm height, 3–2 mm width) were prepared. All defects were filled with a slowly resorbing equine xenograft and covered by a resorbable pericardium membrane. At the test sites, the membrane was apically fixed with pins, while no fixation was applied to the control sites. After 3 months of healing, histomorphometric analyses were performed. Results: The vertical bone gain of the buccal crest was 3.2 mm in the test sites (pin group) and 2.9 mm in the control sites (no-pin) (p > 0.754). No significant difference was found in terms of bone-to-implant contact (BIC). However, residual graft particles were located significantly more coronally in the pin group compared to the no-pin group (p = 0.021). Morphometric analyses revealed similar new bone formation within the groups, but with higher amounts of residual xenograft and soft tissue in the pin group. Conclusions: Membrane fixation did not significantly enhance vertical bone gain, and although the slightly higher regeneration in the pin group (3.2 mm vs. 2.9 mm) may hold clinical relevance in esthetically sensitive areas and osseointegration, it appeared to limit coronal migration of the grafting material. Full article

This study evaluated the bone regeneration effect and mechanical properties of “Sticky bone”, a mixture of platelet-rich fibrin (PRF) and synthetic bone grafts (SBGs), in the repair of large femoral bone defects in rabbits. Eighteen New Zealand white rabbits were included and randomly divided into a Sticky bone group and an SBG alone group. Bone graft samples were collected and analyzed at 4, 8, and 12 weeks after surgery. Micro- computed tomography (CT) analysis showed that the amount of the Sticky bone group in the grayscale ranges of 255–140 (highly mineralized tissue or unabsorbed bone powder) and 140–90 (representing new cancellous bone) was higher than that of the SBG group at each time point and decreased with the number of weeks. The compression strength test showed that the average compression strength of the Sticky bone group reached 5.17 MPa at the 12th week, which was 1.62 times that of the intact bone (3.19 MPa) and was significantly better than that of the SBG group (about 4.12 MPa). This study also confirmed for the first time that the use of a new polyethylene terephthalate (PET) blood collection tube to prepare PRF can stably release key growth factors such as platelet-derived growth factor-BB (PDGF-BB) and vascular endothelial growth factor (VEGF), which are conducive to early bone vascularization and cell proliferation. In summary, Sticky bone has the potential to promote bone formation, enhance tissue integration and mechanical stability, and can be used as an effective alternative material for repairing large-scale bone defects in clinical practice in the future. Full article

Sarcomas are heterogeneous mesenchymal tumors, and their pharmacological treatment remains challenging due to the high toxicity and poor efficacy of current therapies. This study aimed to identify common overexpressed kinases in the four most frequent sarcoma subtypes to establish novel therapeutic targets. A bioinformatics approach using patient-derived gene expression data sets identified overexpressed kinases shared across these sarcoma types. Later, BUB1 was determined as the kinase consistently overexpressed across the osteosarcoma, liposarcoma, leiomyosarcoma, and synovial sarcoma. Moreover, the role of this kinase was further validated through molecular and functional assays, including pharmacological inhibition in cell lines derived from the four sarcoma subtypes. BUB1 inhibition reduced the phosphorylation of AKT and H2A proteins, precluded cell proliferation, and inhibited colony formation in sarcoma cells. Finally, overall survival analysis highlighted a strong correlation between high BUB1 expression and poorer survival rates in sarcoma patients. Altogether, these findings underscore the potential of BUB1 as a therapeutic target and prognostic marker in sarcomas. Targeted inhibition of BUB1 may provide a novel strategy to reduce tumor growth and improve outcomes for patients with bone and soft tissue sarcomas. Full article

Mycobacterium tuberculosis—an acid-fast staining bacterium—is a serious global health challenge that can have both short-term and long-term complications. Although the immune response helps trap the infection, it can also cause necrosis and calcification, leading to lung tissue damage. Calcification is a known outcome of chronic granuloma evolution in TB. Multiple pathways contribute to fibrosis and calcification; some examples are IL-1β, TGF-β, and TNF-α. Current antifibrotic drugs, such as nintedanib and pirfenidone, are effective but may increase the risk of latent tuberculosis reactivation in certain patients. Experimental therapies such as artemisinin derivatives have shown promise in preclinical TB fibrosis models, while cell-based therapies like bone marrow-derived mononuclear cells are also under early investigation for dual antifibrotic and immunomodulatory effects. This literature review will explore recent studies on the pathogenesis of M. tuberculosis, the mechanisms underlying calcification in granuloma formation, and subsequent complications of the disease process. Full article

Background/Objectives: Periodontitis is a chronic inflammation of the periodontium that induces damage in the periodontal ligaments and the surrounding alveolar bone. This study aimed to comparatively evaluate the clinical outcomes of two therapies used in the management of periodontal conditions, represented by scaling and root planing (SRP) alone and laser-assisted new attachment procedure (LANAP). Methods: Two quadrants of the oral cavity from each selected patient were randomly allocated to one of the treatment groups, SRP or LANAP. The periodontal status was documented in a periodontal chart at baseline, six weeks, and one year after treatment. SRP was performed in the first group of patients. The LANAP protocol was carried out on the patients belonging to the second group. Results: The outcomes of the study highlighted that LANAP leads to a reduction in periodontal disease signs (pocket depth, bleeding on probing, and gingival recession), contributing to the formation of new attachment tissues. LANAP shows more stability in maintaining the improvements achieved during six weeks, while SRP shows a slight deterioration in several parameters, particularly attachment loss, between six weeks and one year. The collected data at six-week and one-year follow-ups show improvements in periodontal health, thus improving oral health. Conclusions: Both minimally invasive periodontal procedures were effective, with LANAP demonstrating greater efficiency in patients with chronic periodontal disease, a greater reduction in pocket depth, and improved clinical outcomes compared to SRP alone. Full article

Bioactive glasses are known for their surface reactivity and ability to bond with bone tissue through the formation of hydroxyapatite. This study investigates the effects of substituting ultrapure water with natural geothermal waters from the Azores in the sol–gel synthesis of 45S5 and MgO-modified bioglasses. Using high-resolution X-ray photoelectron spectroscopy (XPS), we examined how the mineral composition of the waters influenced the chemical environment and network connectivity of the glass surface. The presence of trace ions, such as Mg²⁺, Sr²⁺, Zn²⁺, and B³⁺, altered the silicate structure, as evidenced by binding energy shifts and peak deconvolution in O 1s, Si 2p, P 2p, Ca 2p, and Na 1s spectra. Thermal treatment further promoted polymerization and reduced hydroxylation. Our findings suggest that mineral-rich waters act as functional agents, modulating the reactivity and structure of bioactive glass surfaces in eco-sustainable synthesis routes. Full article

Plasma-derived fibrin hydrogels are widely used in tissue engineering because of their excellent biological properties. Specifically, human plasma-derived fibrin hydrogels serve as 3D matrices for autologous skin graft production, skeletal muscle repair, and bone regeneration. Nevertheless, for advanced applications such as in vitro skin equivalents and engineered grafts, the intrinsic limitations of native fibrin hydrogels in terms of long-term mechanical stability and resistance to degradation need to be addressed to enhance the usefulness and application of these hydrogels in tissue engineering. In this study, we chemically modified plasma-derived fibrin by incorporating succinimidyl alginate (SA), a version of alginate chemically modified to introduce reactive succinimidyl groups. These NHS ester groups (N-hydroxysuccinimide esters), attached to the alginate backbone, are highly reactive toward the primary amine groups present in plasma proteins such as fibrinogen. When mixed with plasma, the NHS groups covalently bond to the amine groups in fibrin, forming stable amide linkages that reinforce the fibrin network during hydrogel formation. This chemical modification improved mechanical properties, reduces contraction, and enhanced the stability of the resulting hydrogels. Hydrogels were prepared with a final fibrinogen concentration of 1.2 mg/mL and SA concentrations of 0.5, 1, 2, and 3 mg/mL. The objective was to evaluate whether this modification could create a more stable matrix suitable for supporting skin tissue development. The mechanical and microstructure properties of these new hydrogels were evaluated, as were their biocompatibility and potential to create 3D skin models in vitro. Dermo-epidermal skin cultures with primary human fibroblast and keratinocyte cells on these matrices showed improved dermal stability and better tissue structure, particularly SA concentrations of 0.5 and 1 mg/mL, as confirmed by H&E (Hematoxylin and Eosin) staining and immunostaining assays. Overall, these results suggest that SA-functionalized fibrin hydrogels are promising candidates for creating more stable in vitro skin models and engineered skin grafts, as well as for other types of engineered tissues, potentially. Full article

Background/Objectives: Hypertension is a major contributor to cardiovascular diseases and is often intensified by psychological stress, which can also affect bone metabolism. Although both conditions independently compromise bone health, their combined impact—particularly under acute and chronic stress—remains unclear. This pilot study aimed to assess the effects of such stressors on bone structure in spontaneously hypertensive rats (SHRs). Methods: Forty male rats, both normotensive and SHRs, were randomly assigned to control, acute stress, or chronic stress groups. Acute stress involves a single 2 h physical restraint. Chronic stress was induced over 10 days using alternating stressors: agitation, forced swimming, physical restraint, cold exposure, and water deprivation. Tibial bones were analyzed by microcomputed tomography (micro-CT), and histology was performed using Hematoxylin and Eosin and Masson’s Trichrome stains. Results: Micro-CT showed increased trabecular bone volume in normotensive rats under chronic stress, whereas SHRs displayed impaired remodeling under both stress types. Histological analysis revealed preserved connective tissue overall but evident changes in growth plate structure among stressed rats. SHRs exhibited exacerbated trabecular formation and cartilage abnormalities, including necrotic zones. Conclusions: Both acute and chronic stress, especially in the context of hypertension, negatively affect bone remodeling and maturation. Despite the absence of overt inflammation, structural bone changes were evident, indicating potential long-term risks. These findings highlight the importance of further studies on stress–hypertension interactions in bone health as well as the exploration of therapeutic approaches to mitigate skeletal damage under such conditions. Full article

Magnesium (Mg²⁺) has gained oncologists’ attention due to its wide range of biological functions and frequent use as a complementary or integrative agent. This review outlines Mg’s actions, its complex role in carcinogenesis and tumor risk, and clinical issues. Mg²⁺ is essential in numerous biochemical processes, including adenosine triphosphate production, cellular signal transduction, DNA, RNA and protein synthesis, and bone formation. Pertinent full-text articles were thoroughly examined, and the most relevant ones were selected for inclusion in this review. There is conflicting scientific evidence about the relationship between Mg²⁺ changes and cancer risk, apart from colorectal cancer. Chronic Mg²⁺ deficiency leads to immune dysfunctions and enhanced baseline inflammation associated with oxidative stress related to various age-associated morbidities and cancer. On the other hand, Mg²⁺ deficiency is associated with drug or chemotherapy-related hypomagnesemia, postoperative pain, cachexia, opioid-induced constipation, normal tissue protection from radiation damage, and prevention of nephrotoxicity. A balanced diet usually provides sufficient Mg²⁺, but supplementation may be necessary in some clinical settings. Full article

Periodontitis is an inflammatory disease that affects the periodontal supporting tissues. Its cardinal clinical manifestations encompass gingival inflammation, periodontal pocket formation, and alveolar bone resorption. Urolithin A (UA), a gut microbiota-derived metabolite of ellagitannins, is known for its anti-inflammatory and osseous-protective properties. Nonetheless, the impact of UA on periodontitis remains unknown. To investigate the preventive effect of UA, we employed a lipopolysaccharide (LPS)-induced inflammation model in RAW 264.7 mouse macrophages, a receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation model, and a ligature-induced periodontitis model in mice. The expression of inflammatory factors (tumor necrosis factor-α, TNF-α; interleukin-6, IL-6) was analyzed to assess anti-inflammatory efficacy. Bone loss in mice with periodontitis was assessed through histological and imaging techniques, including haematoxylin and eosin staining to evaluate alveolar bone morphology, Masson’s trichrome staining to visualize collagen fiber distribution, and micro-computed tomography scanning to quantify bone structural parameters. Additionally, we investigated the underlying mechanisms by examining osteoclast activity through tartrate-resistant acid phosphatase staining and the expression levels of proteins RANKL and osteoprotegerin (OPG). We found that UA reduced IL-6 and TNF-α levels in vitro and in vivo, inhibited osteoclast differentiation, and decreased the RANKL/OPG ratio in periodontitis mice. Full article

Bone is a preferred site for disseminated tumor cells, yet the molecular mechanisms that prepare the skeletal microenvironment for metastatic colonization are only beginning to be understood. At the heart of this process are extracellular vesicles (EVs), nano-sized, lipid-encapsulated particles secreted by cancer cells and stromal components. This review consolidates current findings that position EVs as key architects of the bone-metastatic niche. We detail the biogenesis of EVs and their organotropic distribution, focusing on how integrin patterns and bone-specific ligands guide vesicle homing to mineralized tissues. We then outline the sequential establishment of the pre-metastatic niche, driven by EV-mediated processes including fibronectin deposition, stromal cell reprogramming, angiogenesis, neurogenesis, metabolic reconfiguration, and immune modulation, specifically, the expansion of myeloid-derived suppressor cells and impaired lymphocyte function. Within the bone microenvironment, tumor-derived EVs carrying microRNAs and proteins shift the balance toward osteoclastogenesis, inhibit osteoblast differentiation, and disrupt osteocyte signaling. These alterations promote osteolytic destruction or aberrant bone formation depending on tumor type. We also highlight cutting-edge imaging modalities and single-EV omics technologies that resolve EV heterogeneity and identify potential biomarkers detectable in plasma and urine. Finally, we explore therapeutic approaches targeting EVs, such as inhibition of nSMase2 or Rab27A, extracorporeal EV clearance, and delivery of engineered, bone-targeted vesicles, while addressing translational challenges and regulatory considerations. This review offers a roadmap for leveraging EV biology in predicting, preventing, and treating skeletal metastases by integrating advances across basic biology, bioengineering, and translational science. Full article

Mesenchymal stem cells (MSCs) represent a promising cell source for cartilage tissue engineering due to their chondrogenic potential. However, current differentiation protocols result in limited efficiency. This study assessed the combined effects of transforming growth factor-beta 3 (TGF-β3) and fibroblast growth factor-2 (FGF-2) on the morphology, proliferation, chondrogenic differentiation, chondrogenic gene expression, and cytokine profile of ovine bone marrow-derived MSCs (BM-MSCs). BM-MSCs were cultured under four conditions: control (αMEM) or αMEM supplemented with FGF-2, TGF-β3, or TGF-β3 + FGF-2. Morphological and proliferation analyses, Alcian blue staining in 2D and 3D, and real-time PCR for early (Chad, Comp, and Sox 5) and late (Agg, Col IX, Sox 9, and Fmod) chondrogenic markers were performed. Cytokine secretion profiles were analyzed using multiplex assay. TGF-β3 induced morphological changes indicative of early chondrogenesis, while FGF-2 enhanced proliferation. The combination of both cytokines led to a synergistic increase in cell proliferation, early and late chondrogenic gene expression, and glycosaminoglycans (GAG) deposition. Cytokine analysis revealed that TGF-β3 enhanced the immunomodulatory and angiogenic profile of BM-MSCs, whereas co-treatment with FGF-2 yielded a balanced and potentially regenerative secretome. Dual stimulation with TGF-β3 and FGF-2 significantly improves the chondrogenic differentiation of ovine BM-MSCs by enhancing both molecular and functional markers of cartilage formation. Full article